Applied Sciences

Published by MDPI
Online ISSN: 2076-3417
Two α-synuclein ligands, 3-methoxy-7-nitro-10H-phenothiazine (2a, Ki = 32.1 ± 1.3 nM) and 3-(2-fluoroethoxy)-7-nitro-10H-phenothiazine (2b, Ki = 49.0 ± 4.9 nM), were radiolabeled as potential PET imaging agents by respectively introducing (11)C and (18)F. The syntheses of [(11)C]2a and [(18)F]2b were accomplished in a good yield with high specific activity. Ex vivo biodistribution studies in rats revealed that both [(11)C]2a and [(18)F]2b crossed the blood-brain barrier (BBB) and demonstrated good brain uptake 5 min post-injection. MicroPET imaging of [(11)C]2a in a non-human primate (NHP) confirmed that the tracer was able to cross the BBB with rapid washout kinetics from brain regions of a healthy macaque. The initial studies suggested that further structural optimization of [(11)C]2a and [(18)F]2b is necessary in order to identify a highly specific positron emission tomography (PET) radioligand for in vivo imaging of α-synuclein aggregation in the central nervous system (CNS).
Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.
Oblivious transfer (OT) and bit commitment (BC) are two-party cryptographic protocols which play crucial roles in the construction of various cryptographic protocols. We propose three practical quantum cryptographic protocols in this paper. We first construct a practical quantum random oblivious transfer (R-OT) protocol based on the fact that non-orthogonal states cannot be reliably distinguished. Then, we construct a fault-tolerant one-out-of-two oblivious transfer ( O T 1 2 ) protocol based on the quantum R-OT protocol. Afterwards, we propose a quantum bit commitment (QBC) protocol which executes the fault-tolerant O T 1 2 several times. Mayers, Lo and Chau (MLC) no-go theorem proves that QBC protocol cannot be unconditionally secure. However, we find that computing the unitary transformation of no-go theorem attack needs so many resources that it is not realistically implementable. We give a definition of physical security for QBC protocols and prove that the practical QBC we proposed is physically secure and can be implemented in the real world.
We provide a critical review of the fundamental concepts of Kerr lens mode-locking (KLM), along with a detailed description of the experimental considerations involved in the realization of a mode-locked oscillator. In addition, we review recent developments that overcome inherent limitations and disadvantages in standard KLM lasers. Our review is aimed mainly at readers who wish to realize/maintain such an oscillator or for those who wish to better understand this major experimental tool.
We present numerical and analytical results for the reflection and transmission properties of matter wave solitons impinging on localized scattering potentials in one spatial dimension. Our mean field analysis identifies regimes where the solitons behave more like waves or more like particles as a result of the interplay between the dispersive wave propagation and the attractive interactions between the atoms. For a bright soliton propagating together with a dark soliton void in a two-species Bose-Einstein condensate of atoms with repulsive interactions, we find different reflection and transmission properties of the dark and the bright components.
For a real, meaningful pump-probe experiment with attosecond temporal resolution, an isolated attosecond pulse is in demand. In this vein we report the generation of an isolated ~ 148 attosecond pulse duration radiation pulse at 0.1 angstrom wavelength using current enhanced self-amplified spontaneous emission free electron laser. We consider the 10-GeV PAL-XFEL e-beam for enhanced self-amplified spontaneous emission (ESASE) scheme. In ESASE, X-ray SASE FEL is combined with a femtosecond laser system. An 800 nm wavelength, 5 fs FWHM carrier envelope phase stabilized laser was employed in ESASE scheme.
Ultrasonic guided wave testing is an essential technique in non-destructive testing for structural integrity of oil and gas pipelines. This technique, based on the pulse-echo method, is often used for the long-range detection of pipelines at any location. However, guided waves suffer from high attenuation when they propagate in attenuative material structures and multiple wave modes due to the excitation, which reduces the power of echo signals and induces corruption caused by coherent noise. In this paper, a developed hybrid coded excitation method that uses the convolution of a Barker code and Golay code pair is proposed and applied for an ultrasonic guided wave testing system to excite the torsional guided wave mode T(0,1) in a steel pipe. The proposed method combines the advantages of these two coding methods and increases the flexibility of code lengths. The performance is evaluated by signal to noise ratio and peak sidelobe level of the processed signal. Both theoretical simulations and experiments have investigated using the proposed codes composed of Barker codes and Golay code pairs of different lengths and combinations. The experimental results show the significant improvement of the signal to noise ratio and the peak sidelobe level due to the proposed hybrid code usage for the excitation of guided waves. The values are further improved to around 32 dB and around −24 dB, respectively. Overall, the proposed hybrid coded method for improving the echo SNR can benefit from guided wave testing to reduce coherent and random noise levels and many other potential applications.
Dispersion curves of the zero-order axisymmetric UGWs: (a) phase velocity, (b) group velocity and dispersion curves of the asymmetric UGWs: (c) phase velocity, (d) group velocity.
Normalized (a) axial, (b) circumferential and (c) radial displacement distributions of the L(0,1), F(n,1), L(0,2) and F(n,3) UGWs (1 ≤ n ≤ 4) at 110 kHz.
Effects of filter parameters: (a) Bf, (b) Bt, (c) Δf and (d) Br on SNRG and DCRG of the s thesized UGW signals processed by FBR-RC-SSP.
Experimental UGW signals before and after applying GS-SSP and FBR-RC-SSP (1 ≤ defect number ≤ 3, 60° ≤ α ≤ 300°).
Ultrasonic guided wave (UGW) nondestructive testing suffers from poor signal interpretation accuracy caused by the coherent noise that is related to dispersion, multi-mode and mode conversion. In order to split the L(0,2) UGW from the coherent noise, split-spectrum processing with raised cosine filters of constant frequency-to-bandwidth ratio (FBR-RC-SSP) is proposed. With the advantages of time domain resolution and frequency domain split, FBR-RC-SSP is studied based on time-frequency analysis using the chirplet transform, and the effects of filter parameters on signal-to-noise ratio gain (SNRG) and defect-to-coherent noise gain (DCRG) are explained. The excellent effects of eliminating the coherent noise and improving the signal resolution in FBR-RC-SSP are reported by the validation of synthesized, simulated and experimental UGW signals, of which the average SNRG and DCRG are 22.92% and 23.71% higher than those of traditional SSP using Gaussian filters, and it has the potential to locate and characterize defects in further UGW testing research.
Cylindrical pipe tests (constant heat flux). Nusselt numbers from different experimental data in Equations (40)-(45) as a function of the Peclet number.
Cylindrical pipe tests. Nusselt number values for the simulations performed for fluids with Pr = 0.025 and Pr = 0.01 with the KLW and Kays [13] models. The values are compared with the Kirillov [33] and Cheng [4] correlations.
Physical properties used in the simulation for Pr = 0.025 and 0.01.
Cylindrical pipe tests. Numerical comparison of the KLW and Kays [13] models with Kirillov [33] and Cheng [4] correlations for Pr = 0.025 and 0.01.
The study of turbulent heat transfer in liquid metal flows has gained interest because of applications in several industrial fields. The common assumption of similarity between the dynamical and thermal turbulence, namely, the Reynolds analogy, has been proven to be invalid for these fluids. Many methods have been proposed in order to overcome the difficulties encountered in a proper definition of the turbulent heat flux, such as global or local correlations for the turbulent Prandtl number and four parameter turbulence models. In this work we assess a four parameter logarithmic turbulence model for liquid metals based on the Reynolds Averaged Navier-Stokes (RAN) approach. Several simulation results considering fluids with P r = 0 . 01 and P r = 0 . 025 are reported in order to show the validity of this approach. The Kays turbulence model is also assessed and compared with integral heat transfer correlations for a wide range of Peclet numbers.
Density of PZT-BYS(x) ceramics sintered in an O2-rich atmosphere at different temperatures.
The evaluated values of g33 and d33 × g33 of PZT-BYS(x) ceramics as a function of Sb2O3 content at optimum sintered temperature.
A comparison between the present work and recently reported piezoelectric ceramic materials for energy-harvesting applications.
Variation of (a) d 33 and k p ; (b) ε 33 T and grain size as a function of Sb 2 O 3 contents of PZT–BYS(x) ceramics. 
The ferroelectric, dielectric and piezoelectric properties of the PZT-BYS(x) ceramics at the optimum sintering temperature.
The effects of doping antimony oxides (Sb2O3/Sb2O5) on the ferroelectric/piezoelectric and energy-harvesting properties of 0.99Pb(Zr0.53Ti0.47)O3-0.01BiYO3 (PZT-BY) have been studied. The feasibility of doping Sb2O3 and Sb2O5 into the PZT-BY ceramics has also been compared by considering factors such as sintering condition, grain size, density, and electrical properties etc. This work discusses a detailed experimental observation using Sb2O3, because Sb2O5 is relatively expensive and does not follow the stoichiometric reaction mechanism when doped in PZT-BY. The Sb2O3-doped specimens were well sintered by oxygen-rich sintering and reached a maximum density of 99.1% of the theoretical value. X-ray diffraction (XRD) analysis showed a complete solid solution for all the specimens. Scanning electron microscope (SEM) observation revealed that the addition of Sb2O3 inhibits grain growth, and exhibits a denser and finer microstructure. The 0.1 moles of Sb2O3-doped ceramic shows a sharp decrease in the dielectric constant (σ33T = 690), while the piezoelectric charge constant (d33) and electromechanical coupling factor (kp) maintained high values of 350 pC/N and 66.0% respectively. The relatively higher value of d33 and lower σ33T of the 0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y0.9Sb0.1)O3 ceramic resulted in an optimum value of piezoelectric voltage constant (g33 = 57.4 × 10⁻³ Vm/N) and a high figure of merit (d33 × g33 = 20075 × 10⁻¹⁵ m²/N). These values are high compared to recently reported works. Therefore, Sb2O3-doped PZT-BY ceramic could be a promising candidate material for the future study of power-harvesting devices.
Flow diagram of the exclusion and research steps.
The relative periodontitis and caries risk scores after 4 weeks of dexamethasone treatment. (**: Wilcoxon signed-rank test significance level at 0.01; CR-score, relative caries risk score; PR-score, relative periodontitis risk score).
Demographic information and qualitative changes in the oral bacterial species of the oral lichen planus patients before and after the treatment with dexamethasone gargle.
Absolute quantitative changes in the oral microbial species of oral lichen planus patients before and after treatment with dexamethasone gargle.
Few studies have already been performed to assess oral bacteria during steroid therapy for oral lichen planus (OLP). Thus, the aim of our study was to analyze the effect of dexamethasone mouthrinse treatment on the oral bacteria of OLP patients. This prospective study was conducted on patients who were diagnosed with OLP and treated with 0.05% dexamethasone mouthrinse twice per day for 4 weeks. Using unstimulated saliva of the patients before and after treatment, the qualitative and quantitative changes in oral bacteria were analyzed using quantitative real-time polymerase chain reaction (qPCR). The qPCR results were analyzed using Wilcoxon signed-rank test to the quantitative changes with dexamethasone mouthrinse. The statistical significance was considered at a level of 0.05. In total, 20 patients were enrolled in this study, wherein all were noted to show improved symptoms of OLP. Fifteen patients (75%) had a qualitative change in the oral microbial species and an improved relative periodontitis risk score (from 26.1 ± 10.7 to 20.9 ± 9.2; p = 0.008). However, quantitative changes in all species were determined to be not statistically different before and after the treatment. Most OLP patients had a changed microbial community composition after 0.05% dexamethasone mouthrinse for 4 weeks. In particular, the composition of the periodontopathic bacteria was improved after the treatment.
Thickness of the interfacial IMC layers (IMLs) aged at 150 °C. (a): Thickness of Cu6Sn5 + Cu3Sn layer; (b): Thickness of Cu3Sn layer; (c): The computing process of IMC layer's thickness.
Thickness of IMC layers in the interface of solder/Cu during the aging process.
EDS results of spot A and spot B.
In this study, the effect of appropriate Nd addition on improving the high-temperature reliability of Sn-3.8Ag-0.7Cu (SAC387)/Cu solder joint after aging treatment was investigated. The interfacial microstructure of solder joint was refined with proper addition of Nd. This phenomenon could be explained as the adsorbing-hindering effect of surface-active Nd atoms which blocked the growth of brittle intermetallic compounds (IMCs) in the solder joint. Theoretical analysis indicated that 0.05 wt. % addition of Nd could distinctly decrease the growth constant of Cu6Sn5 IMCs and slightly decrease the growth constant of Cu3Sn IMCs respectively. The shear force of SAC387-0.05Nd/Cu solder joint was evidently improved compared with the origin solder joint. In addition, SAC387-0.05Nd/Cu solder joint maintained excellent mechanical property compared with SAC387/Cu solder joint even after 1440 h aging treatment.
OM Microstructure of (a) SAC0307 solder; (b) SAC0307-0.05Pr solder; (c) aged SAC0307 solder at 150 • C for 840 h; (d) aged SAC0307-0.05Pr solder at 150 • C for 840 h, (e) SEM image of aged SAC0307-0.05Pr solder at 150 • C for 840 h.
EDS analyzed results of related IMCs formed in the aged SAC0307-0.05Pr solder.
Detailed thickness change with aged time at the interfaces of solders/Cu.
The evolution of interfacial morphology and shear strengths of the joints soldered with Sn-0.3Ag-0.7Cu (SAC0307) and SAC0307-0.05Pr aged at 150 °C for different times (h; up to 840 h) were investigated. The experiments showed the electronic joint soldered with SAC0307-0.05Pr has a much higher shear strength than that soldered with SAC0307 after each period of the aging process. This contributes to the doping of Pr atoms, “vitamins in alloys”, which tend to be adsorbed on the grain surface of interfacial Cu6Sn5 IMCs, inhibiting the growth of IMCs. Theoretical analysis indicates that doping 0.05 wt.% Pr can evidently lower the growth constant of Cu6Sn5 (DCu6), while the growth constant of Cu3Sn (DCu3) decreased slightly. In addition, the electronic joint soldered with SAC0307-0.05Pr still has better ductility than that soldered with SAC0307, even after a 840-h aging process.
Schematic diagram of the experimental setup.
Instruments used: (a) AM-THz source with Gunn diode and attached horn antenna, (b) AM-THz source and lens holder, (c) Sensor PCB, and (d) Sensor PCB holder with linear motor.
Position determination is an important manufacturing process in many modern industries. The objective of this paper is to present an affordable measurement system that can replace optical position measurement with a laser beam in an opaque environment that prevents the laser beam from penetrating through the fog of gases or other materials that are opaque to optical light. THz waves are a good example of replacing a laser beam, as shown in this article. It is known that THz rays can penetrate fabrics, wood, Styrofoam, etc. The triangulation method using an amplitude modulated THz source proved to be a cost-effective solution for position determination in opaque environments.
Cell viability (%) of extracts of calcium alginate (at 100% v/v) and calcium alginate/CNFs films (at 100% and 10% v/v), culture medium (negative control), and 1000 µM zinc chloride cytotoxic solution (positive control) in human keratinocyte HaCaT cells. Only significant statistical differences were found with the negative control. *** p > 0.001; ns: not significant.
The World Health Organization has called for new effective and affordable alternative antimicrobial materials for the prevention and treatment of microbial infections. In this regard, calcium alginate has previously been shown to possess antiviral activity against the enveloped double-stranded DNA herpes simplex virus type 1. However, non-enveloped viruses are more resistant to inactivation than enveloped ones. Thus, the viral inhibition capacity of calcium alginate and the effect of adding a low amount of carbon nanofibers (0.1% w/w) were explored here against a non-enveloped double-stranded DNA virus model for the first time. The results of this study showed that neat calcium alginate films partly inactivated this type of non-enveloped virus and that including that extremely low percentage of carbon nanofibers (CNFs) significantly enhanced its antiviral activity. These calcium alginate/CNFs composite materials also showed antibacterial properties against the Gram-positive Staphylococcus aureus bacterial model and no cytotoxic effects in human keratinocyte HaCaT cells. Since alginate-based materials have also shown antiviral activity against four types of enveloped positive-sense single-stranded RNA viruses similar to SARS-CoV-2 in previous studies, these novel calcium alginate/carbon nanofibers composites are promising as broad-spectrum antimicrobial biomaterials for the current COVID-19 pandemic.
Temporal dependence of the photoinduced OD change (∆OD) at 70 K (closed black circles). The excitation conditions are 1.56 eV, E || stack polarization, and 7.00 × 10 15 photons/cm 2. The probe photon energy is 0.27 eV with the E ⊥ stack polarization direction. The thin red line indicates the results of the fitting analysis using function (1). The pink, blue, and green dashed lines represent the temporal dependences of each component of fitting function (1).
Over the past two decades (EDO-TTF)2PF6 (EDO-TTF = 4,5-ethylenedioxytetrathiafulvalene), which exhibits a metal–insulator (M–I) phase transition with charge–ordering (CO), has been investigated energetically because of attractive characteristics that include ultrafast and massive photoinduced spectral and structural changes. In contrast, while its crystal structure has much in common with the (EDO-TTF)2PF6 crystal, the organic alloy system of [(EDO-TTF)0.89(MeEDO-TTF)0.11]2PF6 (MeEDO-TTF = 4,5-ethylenedioxy-4′-methyltetrathiafulvalene) exhibits a quite different type of M–I phase transition that is attributed to Peierls instability. Here, an optical study of the static absorption spectra and the time-resolved changes in the absorption spectra of [(EDO-TTF)0.89(MeEDO-TTF)0.11]2PF6 are reported. The observed absorption spectra related to the electronic structure are highly anisotropic. With a reduction in temperature (T), the opening of a small optical gap and a small shift in the center frequency of the C=C stretching mode are observed along with the M–I phase transition. Additionally, photoinduced transient states have been assigned based on their relaxation processes and transient intramolecular vibrational spectra. Reflecting small valence and structural changes and weak donor–anion interactions, a photoinduced transient state that is similar to the thermal-equilibrium high-T metallic phase appears more rapidly in the alloy system than that in (EDO-TTF)2PF6.
This paper presents a Ku-band transmit and receive IC in 0.13 µm CMOS technology for mobile satellite communication beamforming systems. A Ku-band transmit and receive IC is composed of a bi-directional amplifier, a 6-bit phase shifter, and a 6-bit digital step attenuator. The precise trimming bits are implemented in the phase shifter (2.8°) and digital step attenuator (0.5 and 1 dB) for the amplitude and phase error correction. The phase variation range of the phase shifter is 360° with a phase resolution of 5.625°. The attenuation range of 31.5 dB with an amplitude resolution of 0.5 dB is achieved. The gain of 2~5 dB and the input/output return losses of >10 dB are achieved from 12 to 16 GHz. The chip size is 2.5 × 1.5 mm2 including bonding pads. The DC power consumption is 216 mW.
Typical schematic view of PDD calculation for a linear accelerator photon beam in a water phantom. The different parts of the head Linac and the voxels used to score the dose within the box are shown.
Comparison of Geant4-simulated (based on IAEA phase space file) and experimental PDD data for a 6 MV photon beam (field size of 3 × 3 cm 2 ) within water.
Geant4-simulated PDD of adipose, cortical bone, fat, lung and muscle tissues for a 10 × 10 cm 2 field size of a 6 MV photon beam.
Buildup factor for adipose tissue as a function of: (left side) photon energy for fixed depths between 0.5 and 40 mfp and (right side) depth for a fixed photon energy between 0.15 and 15 MeV.
Nowadays, the use of tissue mimicking material (TMM) is widespread in both diagnostic and therapeutic medicine, as well as for quality assurance and control. For example, patient exposure evaluation during therapeutic tests has been commonly measured using TMMs. However, only a few materials have been developed for research use at the megavoltage photon energy encountered in medical radiology. In this paper, we extended our previous work to cover the photon energy range of 0.15–15 MeV for five human tissues (adipose, cortical bone, fat, lung and muscle). As a selection criterion for TMM, other than the attenuation coefficient, we introduced the computation of the buildup factor (BUF) for a given couple of energy and depth based on the geometric progression fitting method. Hence, we developed a C++ program able to compute BUF for depths up to 40 mean free path. Moreover, we simulated the percentage depth dose (PDD) of a 6 MV photon beam through each tissue and their equivalent materials using the Geant4 Monte Carlo toolkit (version 10.5). After the comparison of a set of parameters (mass attenuation and mass energy absorption coefficients, BUF, equivalent and effective atomic numbers, electron density, superficial and maximal dose and dose at 10 and 20 cm depths), we found that SB3 (a mixture of epoxy and calcium carbonate) and MS15 (a mixture of epoxy, phenol, polyethylene and aluminum oxide) accurately imitate cortical bone and muscle tissues, respectively. AP6 (a mixture of epoxy, phenol, polyethylene and teflon), glycerol trioleate and LN1 (a mixture of polyurethane and aluminum oxide) are also suitable TMMs for adipose, fat and lung tissues, respectively. Therefore, this work can be useful to physician researchers in dosimetry and radiological diagnosis.
Interstage matching: (a) AC equivalent circuit of the amplifier; (b) first interstage matching at 42 GHz; (c) second interstage matching at 26 GHz.
Chip micrograph of the full Ka-band amplifier.
Design parameter values of the full Ka-band amplifier.
Performance comparison with previous CMOS-based Ka-band amplifiers.
This paper presents a CMOS wideband amplifier operating in the full Ka-band, with a low gain variation. An inductive neutralization is applied to the amplifier to compensate for the gain roll-off in the high-frequency region. Neutralization inductance is carefully determined considering the tradeoff between stability and gain. To achieve a low gain variation over the full Ka-band, the amplifier employs the frequency staggering technique in which impedance matching for three gain stages is performed at different frequencies of 26, 34, and 42 GHz. The experimental results show that a peak gain of 13.2 dB is achieved at 39.2 GHz. The 3 dB bandwidth is from 23.5 to 41.7 GHz, which fully covers the Ka-band. Especially, the gain ripple of the amplifier is only 13 ± 0.2 dB over a wide bandwidth from 26.2 to 40.2 GHz. The input and output return loss values are better than −10 dB from 26.3 to 40.1 GHz and from 25.3 to 50 GHz, respectively. The DC power consumption is 18.6 mW.
For a long time, Chlorhexidine digluconate (CHX) has been considered the most used mouth-rinse for reducing plaque and gingivitis. Sea4® Encias is a new seawater-based mouth rinse with a similar action to CHX. Its prolonged use produces fewer side effects. This study compared the effects of two oral rinses: Chlorhexidine 0.20% and Sea 4® Encias (seawater) for reducing plaque and gingivitis indices. This double-blind crossover study recruited and monitored 93 volunteer dental students, hygienists and doctors from the Universidad Católica de Murcia (UCAM), for 1 month, and compared the efficacy of Chlorhexidine 0.20% (Group A); Sea4® Encías (Group B); and a placebo saline solution (Group C) mouth-rinses for reducing plaque and gingivitis indices. Plaque and gingival inflammation (Löe and Silness test) were evaluated at baseline and after each study stage. Group A reduced plaque growth and gingivitis significantly compared with Groups B and C; Group B was more effective than Group C. The mean P.I. decreased similarly in groups A and B. However, Group A showed the statistically significant value compared with other groups. Group A and group B, showed greater reduction in Gingival Indexes compared with group C. The Sea4 mouthwash showed better inhibitory activity on plaque (1.32 ± 0.22) compared with CHX (1.97 ± 0.34) and saline (2.78 ± 0.11). Sea4 Encias and Chlorhexidine 0.20% mouth-rinses significantly reduce plaque growth and G.I. compared with saline mouth-rinse; Sea4 Encías mouth-rinse is more effective against plaque regrowth than Chlorhexidine in this pilot study.
The carbon nanotube (CNT) cold cathode is an attractive choice for millimeter and terahertz vacuum electronic devices owning to its unique instant switch-on and high emission current density. A novel, dual-gridded, field emission architecture based on a CNT cold cathode is proposed here. CNTs are synthesized directly on the cathode surface. The first separating grid is attached to the CNT cathode surface to shape the CNT cathode array. The second separating grid is responsible for controlled extraction of electrons from the CNT emitters. The cathode surface electric field distribution has been improved drastically compared to conventional planar devices. Furthermore, a high-compression-ratio, dual-gridded, CNT-based electron gun has been designed to further increase the current density, and a 21 kV/50 mA electron beam has been obtained with beam transparency of nearly 100%, along with a compression ratio of 39. A 0.22 THz disk-loaded waveguide backward wave oscillator (BWO) based on this electron gun architecture has been realized theoretically with output power of 32 W. The results indicate that higher output power and higher frequency terahertz BWOs can be made using advanced, nanomaterial-based cold cathodes.
Fitted curves of the highest normalized mass sensitivity and optimum design of normalized layer thickness for the first order mode sensor with the CFEC/Mn:0.24PIN-0.46PMN-0.30PT structure in the range of 25-55°C.
Elastic constants of the CFEC for the CFs along the x-axis and y-axis.
it was found that the changing trend of the highest normalized
Optimum design parameters of normalized layer thickness (h/λ) opt and corresponding
TCF and normalized mass sensitivity S f m λ for a sensor operating in the first order mode with the CFs in CFEC waveguide along the x-axis.
Love wave sensors have attracted significant interest due to their high sensitivity and low attenuation. Love mode acoustic dispersion relation, highest normalized mass sensitivity, optimum normalized waveguide layer thickness, and temperature coefficients of frequency (TCF) were theoretically studied for the carbon fiber epoxy composites (CFEC)/Mn:0.24PIN-0.46PMN-0.30PT structure sensor. The highest normalized mass sensitivity exhibits a decreasing trend as the temperature increases from 25 °C to 55 °C. TCF can be improved by increasing the normalized layer thickness (h/λ); however, the temperature dependence of normalized mass sensitivity decreases. For the carbon fibers (CFs) in the CFEC waveguide along the propagation direction of Love wave, the device has a relatively small TCF of −10.92 ppm/°C at h/λ = 0.4001, where the normalized mass sensitivity is approximately 1.5 times that of a typical fused quartz/ST-quartz configuration device. The theoretical results imply that good temperature stability and high measurement precision were obtained from the device in the system CFEC/Mn:0.24PIN-0.46PMN-0.30PT with the CFs in the CFEC along the propagation direction of Love wave (x-axis). The ideal waveguide material requires a small elastic constant c44; however, the ideal piezoelectric substrate requires large elastic constants c44E and c66E.
Microphotograph of the S/C/X-band 4-bit GaN digital step attenuator MMIC and test module.
Measured (a) S21, and (b) normalized attenuation of the GaN digital step attenuator MMIC.
Component values of T-type resistive attenuators.
Performance comparison of the relevant digital control step attenuators.
In this paper, a 4-bit digital step attenuator using 0.25 μm GaN HEMT technology for wideband radar systems is presented. A switched-path attenuator topology with resistive T-type attenuators and double-pole double-throw (DPDT) switches was used to achieve both low insertion loss and phase/amplitude error. The measured insertion loss of the reference state is 2.8–8.3 dB at DC-12 GHz. The input and output return loss are less than 12 dB at DC-12 GHz. An attenuation coverage of 30 dB with a least significant bit of 2 dB was achieved at DC-12 GHz. A root mean square (RMS) amplitude error of 1dB and a phase error of 8.5° were achieved, respectively. The attenuator chip size is 2.45 mm × 1.75 mm including pads. To the best of the authors’ knowledge, this is the first demonstration of a GaN-based digital step attenuator.
A novel, inverter-based, fully differential, body-driven, rail-to-rail, input stage topology is proposed in this paper. The input stage exploits a replica bias control loop to set the common mode current and a common mode feed-forward strategy to set its output common mode voltage. This novel cell is used to build an ultralow voltage (ULV), ultralow-power (ULP), two-stage, unbuffered operational amplifier. A dual path compensation strategy is exploited to improve the frequency response of the circuit. The amplifier has been designed in a commercial 130 nm CMOS technology from STMicroelectronics and is able to operate with a nominal supply voltage of 0.3 V and a power consumption as low as 11.4 nW, while showing about 65 dB gain, a gain bandwidth product around 3.6 kHz with a 50 pF load capacitance and a common mode rejection ratio (CMRR) in excess of 60 dB. Transistor-level simulations show that the proposed circuit outperforms most of the state of the art amplifiers in terms of the main figures of merit. The results of extensive parametric and Monte Carlo simulations have demonstrated the robustness of the proposed circuit to PVT and mismatch variations.
(a) Drag coefficient, C D , vs. Reynolds number, Re, for the three experimental conditions. Data points are colored according to M. Previously published models are provided for comparison. Error bars correspond to a 95% confidence interval (±2 standard deviations). (b) Approximate fluid flow characteristics at supersonic, high subsonic, and low subsonic microsphere velocities. Black lines represent the extents of the recirculation region, while blue lines represent streamlines. A detached bow shock is present in the supersonic condition. Steady flow features are depicted because Re values for nearly all microsphere flights studied in this work fall below the 270-300 range when the onset of unsteady vortex shedding occurs for spheres.
Drag coefficient, C D , vs. Reynolds number, Re, at 1.2 < M < 4 for the three supersonic experimental conditions are displayed with the data of Kane [12], Wegener and Ashkenas [13], Aroesty [14], and Bailey and Hiatt [15]. The shaded region indicates the Carlson-Hoglund model's range for 1.2 < M < 4. Data points are colored according to the M/ √ Re flow regime metric from 0.1 to 0.7, where increasing values correspond to increasingly rarefied conditions. Data points in black with M/ √ Re < 0.1 belong to the slip-flow regime.
The acceleration of microparticles to supersonic velocities is required for microscopic ballistic testing, a method for understanding material characteristics under extreme dynamic conditions, and for projectile gene and drug delivery, a needle-free administration technique. However, precise aerodynamic effects upon supersonic microsphere motion at sub-300 Reynolds numbers have not been quantified. We derive drag coefficients for microspheres traveling in air at subsonic, transonic, and supersonic velocities from the measured trajectories of microspheres launched by laser-induced projectile acceleration. Moreover, the observed drag effects on microspheres in atmospheric (760 Torr) and reduced pressure (76 Torr) are compared with existing empirical data and drag coefficient models. We find that the existing models adequately predict the drag coefficient for subsonic microspheres, while rarefaction effects cause a discrepancy between the model and empirical data in the supersonic regime. These results will improve microsphere flight modeling for high-precision microscopic ballistic testing and projectile gene and drug delivery.
Maximum distance from TS with a 250 kVA transformer to SU when PTL wires are of different cross-sections.
Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.
In this paper, the effects of different tempering temperatures on a recently developed ultrahigh-strength steel with 0.4 wt.% carbon content were studied. The steel is designed to be used in press-hardening for different wear applications, which require high surface hardness (650 HV/58 HRC). Hot-rolled steel sheet from a hot strip mill was austenitized, water quenched and subjected to 2-h tempering at different temperatures ranging from 150 °C to 400 °C. Mechanical properties, microstructure, dislocation densities, and fracture surfaces of the steels were characterized. Tensile strength greater than 2200 MPa and hardness above 650 HV/58 HRC were measured for the as-quenched variant. Tempering decreased the tensile strength and hardness, but yield strength increased with low-temperature tempering (150 °C and 200 °C). Charpy-V impact toughness improved with low-temperature tempering, but tempered martensite embrittlement at 300 °C and 400 °C decreased the impact toughness at −40 °C. Dislocation densities as estimated using X-ray diffraction showed a linear decrease with increasing tempering temperature. Retained austenite was present in the water quenched and low-temperature tempered samples, but no retained austenite was found in samples subjected to tempering at 300 °C or higher. The substantial changes in the microstructure of the steels caused by the tempering are discussed.
(a) XRD spectra of Si0.5Ge0.5 and Ge films grown on Si (001); (b) The SAED and lowmagnification TEM image of the Si0.5Ge0.5 film grown on Si (001); (c,d) are AFM images of Si0.5Ge0.5 and Ge films, respectively; (e,f) shows the typical etch pits distribution of the Si1−xGex thin films (x from 0.5 to 1), with TDD of 10 3 -10 4 /cm 2 level. The films were etched by Secco etchant. All films are 200 nm thick and grown at 200 °C.
Single-crystalline Si1−xGex thin films on Si (100) with low threading dislocation density (TDD) are highly desired for semiconductor industrials. It is challenging to suppress the TDD since there is a large mismatch (4.2%) between Ge and Si—it typically needs 106–107/cm2 TDD for strain relaxation, which could, however, cause device leakage under high voltage. Here, we grew Si1−xGex (x = 0.5–1) films on Si (001) by low temperature molecular beam epitaxy (LT-MBE) at 200 °C, which is much lower than the typical temperature of 450–600 °C. Encouragingly, the Si1−xGex thin films grown by LT-MBE have shown a dramatically reduced TDD down to the 103–104/cm2 level. Using transmission electron microscopy (TEM) with atomic resolution, we discovered a non-typical strain relaxation mechanism for epitaxial films grown by LT-MBE. There are multiple-layered structures being introduced along out-of-plane-direction during film growth, effectively relaxing the large strain through local shearing and subsequently leading to an order of magnitude lower TDD. We presented a model for the non-typical strain relaxation mechanism for Si1−xGex films grown on Si (001) by LT-MBE.
Electrochemical corrosion of thermo-mechanically processed (TMP) and recrystallized Fe−30Mn−5Al−0.5C twinning-induced plasticity (TWIP) steels containing 30 wt.% Mn was studied in a 1.0 wt.% NaCl electrolyte solution. The alkaline nature of the corrosion products containing manganese oxide (MnO) increases the dissolution kinetics of the TWIP steel in acid media, obtaining Mn2+ cations in solution, and producing the hydrogen evolution reaction (HER). X-ray photoelectron spectroscopy (XPS) surface analysis revealed an increased Al2O3 content of 91% in the passive layer of the recrystallized TWIP steel specimen, while in contrast only a 43% Al2O3 was found on the TMP specimen. Additionally, the chemical composition of the surface oxide layer as well as the TWIP alloy microstructure was analyzed by optical microscopy (OM) and scanning electron microscopy (SEM). The results indicate an enhanced corrosion attack for the TMP high-Mn TWIP steel.
Optical images of samples: (a) Mg-0.5Ca-0.5Gd; (b) Mg-0.5Ca-1Gd; (c) M (d) Mg-0.5Ca-2Gd; (e) Mg-0.5Ca-3Gd.
XRD pattern of Mg-0.5Ca-xGd samples.
Magnesium and Mg-based master alloy weight percentages [41,42].
Initial materials masses used formetal charges in order to obtain the experimental samples.
Lattice parameters of Mg-0.5Ca-xGd alloy phases.
The subject of Mg-based biodegradable materials, used for medical applications, has been extensively studied throughout the years. It is a known fact that alloying Mg with biocompatible and non-toxic elements improves the biodegradability of the alloys that are being used in the field of surgical applications. The aim of this research is to investigate the aspects concerning the microstructure, electrochemical response (corrosion resistance) and in vitro cytocompatibility of a new experimental Mg-based biodegradable alloy—Mg–0.5%Ca with controlled addition of Gd as follows: 0.5, 1.0, 1.5, 2.0 and 3.0 wt.%—in order to establish improved biocompatibility with the human hard and soft tissues at a stable biodegradable rate. For this purpose, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), light microscopy (LM) and X-ray diffraction (XRD) were used for determining the microstructure and chemical composition of the studied alloy and the linear polarization resistance (LPR) method was used to calculate the corrosion rate for the biodegradability rate assessment. The cellular response was evaluated using the 3-(4,5-dimethyltiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test followed by fluorescence microscopy observation. The research led to the discovery of a dendritic α-Mg solid solution, as well as a lamellar Mg2Ca and a Mg5Gd intermetallic compound. The in vivo tests revealed 73–80% viability of the cells registered at 3 days and between 77 and 100% for 5 days, a fact that leads us to believe that the experimental studied alloys do not have a cytotoxic character and are suitable for medical applications.
Some properties of the samples used in the wear tests.
Wear rate values for samples under various applied loads. 
SEM images of samples under a normal load of 90 N at sliding speed of 0.188 m/s. (a,b) Al-5Si-1Cu-0.5Mg alloy, (c,d) SiCp/Al-5Si-1Cu-0.5Mg composites before T6 treatment and (e,f) after T6 treatment.
SEM images of SiCp/Al-5Si-1Cu-0.5Mg composites after T6 heat treatment under normal loads of (a) 15 N, (b) 30 N, (c) 60 N; (d) edging morphology of the as-cast Al-5Si-1Cu-0.5Mg pin sample at 90 N. 
This paper investigated the influence of heat treatment (T6) on the dry sliding wear behavior of SiCp/Al-5Si-1Cu-0.5Mg composite that was fabricated by electromagnetic stirring method. The wear rates and friction coefficients were measured using a pin-on-disc tribometer under loads of 15-90 N at dry sliding speeds of 100 r/min, 200 r/min, and 300 r/min, over a sliding time of 15 min. The worn surfaces and debris were examined using a scanning electron microscope and was analyzed with an energy dispersive spectrometer. The experimental results revealed that SiCp/Al-5Si-1Cu-0.5Mg alloy treated with T6 exhibited lower wear rate and friction coefficient than the other investigated alloys. As the applied load increased, the wear rate and friction coefficient increased. While, the wear rate and friction coefficient decreased with the sliding speed increasing. The morphology of the eutectic silicon was spheroidal after the T6 heat treatment. SiCp particles and Al2Cu phase can be considered as the main raisons for improving the wear behavior. Abrasion and oxidation were the wear mechanisms at low load levels. However, the wear mechanisms at high load levels were plastic deformation and delamination.
A miniaturized 150 kV DC photocathode gun is developed at Peking University to generate electron beam which can be manipulated in temporal and spatial distribution as requirements freely. To measure the bunch length which is an important temporal parameter of the low energy electron beam from the DC photocathode gun, a 1.3 GHz medium-β disk-loaded deflecting cavity is adopted. In this paper we present the design of the deflecting cavity which involves the microwave design including the geometry optimization and the separation of the orthogonal dipole modes as well as the power coupling, the mechanical design including the determination of the cavity wall thickness and the tuning as well as brazing structure, and the thermodynamic analysis. Particle tracking simulation shows that the best resolution of 190 fs can be achieved for the 150 keV electron beam by using the deflecting cavity. Its fabrication is completed and the RF measurements are carried out with a vector network analyzer. It is shown the measured values of the RF physical parameters are in good agreement with the simulation design ones.
Wire arc additive manufacturing (WAAM) system.
Microstructure of the as-deposition WAAM alloys. (a-c) The microstructure near PZ of WAAM alloy of 1#, 10# and 17#; (d-f) the microstructure in HAZ of WAAM alloy of 1#, 10# and 17#; (g-i) the microstructure in the ACZ of WAAM alloy of 1#, 10# and 17#; (j-l) the microstructure amplification structure in the ACZ of WAAM alloy of 1#, 10# and 17#.
Mechanical properties of the T6-treated WAAM alloy.
Chemical composition of raw materials and substrates (wt %).
Process parameters.
In order to improve the forming efficiency of Al–7Si–0.6Mg fabricated by wire and arc additive manufacturing process (WAAM), wire with a diameter of 1.6 mm was selected as the raw material. The effect of heat input on the formability, microstructure, and properties of the WAAM alloy was investigated, and the forming model was established. The WAAM alloys were characterized by electronic universal testing, scanning electron microscopy, energy spectrum analysis, and metallographic microscopy. The results show that Al–7Si–0.6Mg alloy has a large processing window under the cold metal transfer (CMT) process, and it can be well formed with a large range of heat input. The secondary dendrite arm spacing and Fe-phase in the as-deposited alloy gradually increase with an increase in heat input, and slight overburning occurs in the heat affected zone at higher heat inputs. After solid solution and aging treatment (T6 heat treatment), the size of α-Al grain and eutectic silicon grain increases with the increase of heat input. Little anisotropy in the mechanical properties is observed except at higher heat inputs. The tensile strength is 354.5 MPa ± 7.5 MPa, yield strength is 310 MPa ± 5.5 MPa, and elongation is 6.3 ± 0.7%.
Experimental response at RT (symbols) plotted as R (blue) and G (black) peaks, together with the reconstructed spectra after parameter determination by iterative analysis (continuous lines), for: (A) planar and (B) thickness resonance modes of a thickness-poled, thin disk of BNBT6 (t = 1.91 mm and D = 10.60 mm); and for a shear resonance of a thickness-poled, thin plate of BNBT6 (9.53 × 9.43 mm): (C) with t = 0.89, with strong coupling of modes and not fitted for parameters determination; and (D) with t = 0.83 mm, virtually uncoupled. The regression factor of the reconstructed to the experimental spectra (R 2 ) is shown for each analyzed resonance. 
Sensitivity analysis for the real part of the elastic constants. Each curve shows the evolution of a resonance using the conductivity G. Each parameter is changed over a range ±50% from the initial value. 
Thermal evolution of the imaginary part of the elastic, dielectric, and piezoelectric parameters. Parameters related with the thickness mode (high sensitivity) are represented in red. Those related with the radial modes are represented in black, and those related with the complex resonances C 1 and C 2 in blue. 
(Bi0.5Na0.5)0.94Ba0.06TiO3 dense ceramics were obtained from autocombustion sol-gel synthesized nanopowders and sintered at 1050 °C for 1-2 h for the study of the electromechanical anisotropy. Measurement of the complex impedance spectrum was carried out on thin ceramic disks, thickness-poled, as a function of the temperature from 16 °C up to the vanishing of the electromechanical resonances at the ferroelectric to relaxor transition near 100 °C. The spectrum comprises the fundamental radial extensional mode and three overtones of this, together with the fundamental thickness extensional mode, coupled with other complex modes. Thermal evolution of the spectrum shows anisotropic behavior. Piezoelectric, elastic, and dielectric material coefficients, including all losses, were determined from iterative analysis of the complex impedance curves at the planar, thickness, and shear virtually monomodal resonances of disks and shear plates, thickness-poled. d33 was measured quasi-statically at 100 Hz. This set of data was used as the initial condition for the optimization of the numerical calculation by finite elements of the full spectrum of the disk, from 100 kHz to 1.9 MHz, to determine the thermal evolution of the material coefficients. An appropriate measurement strategy to study electromechanical anisotropy of piezoelectric ceramics has been developed.
TiO 2 anatase (001) surface has been indicated for many years as a potential system for water dissociation and hydrogen production. Surface reconstruction periodicity of TiO 2 anatase (001) in water is revised on the basis of the new water induced reconstruction model that accounts for dissociative water adsorption in the first monolayer and self-assembling of surface hydroxyls. The study has been performed in the context of first principles total energy calculations on the basis of state of the art Density Functional Theory. Different surface periodical structures have been studied and compared in terms of residual surface stress and surface reactivity. While a preference seems to emerge for the (2 × 3) surface reconstruction, there are indications that this configuration might not occur spontaneously in bulk water.
XRD patterns of TiO 2 , Fe 3 O 4 and Fe 3 O 4 @TiO 2 .
Raman spectra in the range of 100-800 cm −1 for TiO 2 and Fe 3 O 4 @TiO 2 .
FESEM images. (a) Fe 3 O 4 ; (b) TiO 2 ; (c) Fe 3 O 4 @TiO 2 .
Photocatalytic degradation of AR73 by (a) Fe 3 O 4 @TiO 2 and (b) TiO 2 ; (c) the rate of degradation of AR73 by Fe 3 O 4 @TiO 2 and TiO 2 in a dark reaction time of 25 min and irradiation time of 24 min; (d) magnetically adsorbed Fe 3 O 4 @TiO 2 .
Water pollution can be treated through the photocatalytic reaction of TiO2 or TiO2 compounds. A solvothermal method was used to prepare Fe3O4 and Fe3O4@TiO2 composite photocatalyst with (001) high-energy facets exposed in the anatase phase. TiO2 and Fe3O4@TiO2 were characterized by field emission scanning electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, X-ray diffraction spectroscopy and Raman spectroscopy. It was found that the composite Fe3O4@TiO2 can reduce the band gap and maintain a certain proportion of (001) high-energy facet exposure. The band gaps of Fe3O4@TiO2 and TiO2 are 2.5 eV and 2.9 eV, respectively. The exposure percentages of (001) facets of Fe3O4@TiO2 and TiO2 are about 25.2% and 12.1%, respectively. Fe3O4@TiO2 was used for photocatalytic degradation of Acid Red 73, and it was found that Fe3O4@TiO2 could improve the efficiency of photocatalytic degradation of Acid Red 73. The photocatalytic degradation rates of Fe3O4@TiO2 and TiO2 at 24 min were 93.56% and 74.47%, respectively. The cycle experiment of photocatalytic degradation of Acid Red 73 by Fe3O4@TiO2 showed that at the fifth cycle, the rate of dye degradation decreased to 77.05%, but the rate of dye degradation can reach more than 90% after self-cleaning treatment. The photocatalytic degradation mechanism is explained by the energy band theory and the first-order kinetic equation model.
Schematic diagram of the c-ZrO2(001)/α-Al2O3(11 02) interfacial shear simulation. The red, pink, and blue spheres represent O, Al, and Zr atoms, respectively. To better demonstrate the system, the model has been duplicated in the horizontal direction.
The energy Φ as a function of the shear displacement δ of the c-ZrO2(001)/α-Al2O3 (11 02) interface models.
The evolution of the atomic structures at the c-ZrO2(001)/α-Al2O3(11 02) interfaces during the shearing process: (a) O-<11 01>, (b) O-<112 0>, (c) 2O-<11 01>, (d) 2O-<112 0>, (e) Zr-<11 01>, and (f) Zr-<112 0>. The red, grey, and green spheres represent O, Al, and Zr atoms, respectively.
The ideal mechanical shear properties and sliding characteristics of c-ZrO2(001)/α-Al2O3(11¯02) interfaces are examined through simulated shear deformations using first-principles calculations. We investigate three types of interface models, abbreviated as O-, 2O-, and Zr- models, when shear displacements are applied along the <11¯01> and <112¯0> directions of their Al2O3 lattice. The theoretical shear strength and unstable stacking energy of the ZrO2/Al2O3 interfaces are discussed. In the process of the ZrO2/Al2O3 interfacial shear deformation, we find that the sliding of the ZrO2 atomic layers, accompanied by the shifting of Zr atoms and Al atoms near the interface, plays a dominant role; in addition, the ZrO2/Al2O3 interfaces fail within the ZrO2 atomic layer. Among the three models, the O- model exhibits the strongest shear resistance; whereas the Zr- model is the most prone to slip. Furthermore, their tensile and shear strengths are compared; moreover, their potential applications are provided.
(a,b) are SEM images of the as-grown ZnO thin films on quartz glass and sapphire (001) substrates annealed at 600 • C for 1 h, respectively. (c,d) are their cross-section SEM images, respectively. (e,f) are their corresponding AFM images, respectively.
Ultraviolet-visible (UV-Vis) transmittance spectra of the as-received ZnO thin films grown on the (a) quartz glass and (b) sapphire (001) substrates, respectively.
Oxygen-related XPS characteristic parameters for the as-grown ZnO thin films on quartz glass and sapphire (001) substrates annealed at 600 • C for 1 h.
In this work, we reported a comparative study of ZnO thin films grown on quartz glass and sapphire (001) substrates through magnetron sputtering and high-temperature annealing. Firstly, the ZnO thin films were deposited on the quartz glass and sapphire (001) substrates in the same conditions by magnetron sputtering. Afterwards, the sputtered ZnO thin films underwent an annealing process at 600 °C for 1 h in an air atmosphere to improve the quality of the films. X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectra, photoluminescence spectra, and Raman spectra were used to investigate the structural, morphological, electrical, and optical properties of the both as-received ZnO thin films. The ZnO thin films grown on the quartz glass substrates possess a full width of half maximum value of 0.271° for the (002) plane, a surface root mean square value of 0.50 nm and O vacancies/defects of 4.40% in the total XPS O 1s peak. The comparative investigation reveals that the whole properties of the ZnO thin films grown on the quartz glass substrates are comparable to those grown on the sapphire (001) substrates. Consequently, ZnO thin films with high quality grown on the quartz glass substrates can be achieved by means of magnetron sputtering and high-temperature annealing at 600 °C.
Single neutral silicon-vacancy ( SiV 0 ) color centers under H-, O-, or N-terminated diamond (001) surfaces were investigated using density functional theory. The formation energy calculation indicated that it is generally easier for SiV 0 to be embedded in an O-terminated diamond (001) surface as compared with H- and N-terminated surfaces, which were effected above the fifth C layer. The effects of the surface termination species on inner diamond atoms decay to be negligible below the fifth C layer. The binding energy results indicated that SiV centers exhibited rather high energetic stability once formed. Additionally, it was revealed that these three surface-terminating species had contracting or expanding effects on inner surface atoms. The calculation for density of states showed that the N-terminated diamond (001) surface served as a suitable medium for single SiV 0 to function as a single-photon source.
Well logging is a significant procedure that assists geophysicists and geologists with making predictions regarding boreholes and efficiently utilizing and optimizing the drilling process. The current study area is positioned in the Punjab Territory of Pakistan, and the geographic coordinates are 30020′10 N and 70043′30 E. The objective of the current research work was to interpret the subsurface structure and reservoir characteristics of the Kabirwala area Tola (01) well, which is located in the Punjab platform, Central Indus Basin, utilizing 2D seismic and well log data. Formation evaluation for hydrocarbon potential using the reservoir properties is performed in this study. For the marked zone of interest, the study also focuses on evaluating the average water saturation, average total porosity, average effective porosity, and net pay thickness. The results of the study show a spotted horizon stone with respect to time and depth as follows: Dunghan formation, 0.9 s and 1080.46 m; Cretaceous Samana Suk formation, 0.96 s and 1174.05 m; Datta formation, 1.08 s and 1400 m; and Warcha formation, 1.24 s and 1810 m. Based on the interpretation of well logs, the purpose of petrophysical analysis was to identify hydrocarbon-bearing zones in the study area. Gamma ray, spontaneous potential, resistivity, neutron, and density log data were utilized. The high zone present in the east–west part of the contour maps may be a possible location of hydrocarbon entrapment, which is further confirmed by the presence of the Tola-01 well.
Clinical status of LCL161 for cancer treatment.
Clinical status of birinapant (TL32711) for cancer treatment.
Inhibitor of apoptosis proteins (IAPs) are suggested as therapeutic targets for cancer treatment. Smac/DIABLO is a natural IAP antagonist in cells; therefore, Smac mimetics have been developed for cancer treatment in the past decade. In this article, we review the anti-cancer potency and novel molecular targets of LCL161, birinapant, and GDC-0152. Preclinical studies demonstrated that Smac mimetics not only induce apoptosis but also arrest cell cycle, induce necroptosis, and induce immune storm in vitro and in vivo. The safety and tolerance of Smac mimetics are evaluated in phase 1 and phase 2 clinical trials. In addition, the combination of Smac mimetics and chemotherapeutic compounds was reported to improve anti-cancer effects. Interestingly, the novel anti-cancer molecular mechanism of action of Smac mimetics was reported in recent studies, suggesting that many unknown functions of Smac mimetics still need to be revealed. Exploring these currently unknown signaling pathways is important to provide hints for the modification and combination therapy of further compounds.
The ever-growing number of applications for satellites is being compromised by their poor direct positioning precision. Existing orthoimages, such as enhanced thematic mapper (ETM+) orthoimages, can provide georeferences or improve the geo-referencing accuracy of satellite images, such ZY-1-02C images that have unsatisfactory positioning precision, thus enhancing their processing efficiency and application. In this paper, a feasible image matching approach using multi-source satellite images is proposed on the basis of an experiment carried out with ZY-1-02C Level 1 images and ETM+ orthoimages. The proposed approach overcame differences in rotation angle, scale, and translation between images. The rotation and scale variances were evaluated on the basis of rational polynomial coefficients. The translation vectors were generated after blocking the overall phase correlation. Then, normalized cross-correlation and least-squares matching were applied for matching. Finally, the gross errors of the corresponding points were eliminated by local statistic vectors in a TIN structure. Experimental results showed a matching precision of less than two pixels (root-mean-square error), and comparison results indicated that the proposed method outperforms Scale-Invariant Feature Transform (SIFT), Speeded Up Robust Features (SURF), and Affine-Scale Invariant Feature Transform (A-SIFT) in terms of reliability and efficiency.
In this paper, the authors describe a conformance testing system for SGSF-064-1, the communication protocol between electric vehicles and conductive DC (direct current) chargers in Korea. Since the SGSF-064-1 is based on CAN (controller area network), the testing system was developed by CANoe. The DC charger known as EVSE (electric vehicle supply equipment) is the system being tested and the developed system implemented in PC (personal computer). The developed system performs as a tester to ensure that the DC chargers from various manufactures can conform to the communication protocol in SGSF-064-1. The testing system contains four testing modes which also consist of several test cases.
The prediction of internal combustion engine performance and emissions in real driving conditions is getting more and more important due to the upcoming stricter regulations. This work aims at introducing and validating a new transient simulation methodology of an ICE coupled to a hybrid architecture vehicle, getting closer to real-time calculations. A one-dimensional computational fluid dynamic software has been used and suitably coupled to a vehicle dynamics model in a user function framework integrated within a Simulink® environment. A six-cylinder diesel engine has been modeled by means of the 1D tool and cylinder-out emissions have been compared to experimental data. The measurements available have been used also to calibrate the combustion model. The developed 1D engine model has been then used to perform driving cycle simulations considering the vehicle dynamics and the coupling with the energy storage unit in the hybrid mode. The map-based approach along with the vehicle simulation tool has also been used to perform the same simulation and the two results are compared to evaluate the accuracy of each approach. In this framework, to achieve the best simulation performance in terms of computational time over simulated time ratio, the 1D engine model has been used in a configuration with a very coarse mesh. Results have shown that despite the high mesh spacing used the accuracy of the wave dynamics prediction was not affected in a significant way, whereas a remarkable speed-up factor was achieved. This means that a crank angle resolution approach to the vehicle simulation is a viable and accurate strategy to predict the engine emission during any driving cycle with a computation effort compatible with the tight schedule of a design process.
1,1,1,2,3,3,3-Heptafluoropropane (R227ea) is a good refrigerant that reduces greenhouse effects and ozone depletion. In practical applications, we usually have to know the compressed liquid densities at different temperatures and pressures. However, the measurement requires a series of complex apparatus and operations, wasting too much manpower and resources. To solve these problems, here, Song and Mason equation, support vector machine (SVM), and artificial neural networks (ANNs) were used to develop theoretical and machine learning models, respectively, in order to predict the compressed liquid densities of R227ea with only the inputs of temperatures and pressures. Results show that compared with the Song and Mason equation, appropriate machine learning models trained with precise experimental samples have better predicted results, with lower root mean square errors (RMSEs) (e.g., the RMSE of the SVM trained with data provided by Fedele et al. [1] is 0.11, while the RMSE of the Song and Mason equation is 196.26). Compared to advanced conventional measurements, knowledge-based machine learning models are proved to be more time-saving and user-friendly.
The first and last snapshots in the first simulations systems (a); the most populated structures of L-Phes and D-Phes in the first simulations (b). Tail groups of DMPC membrane were omitted for the clarity.
The last snapshots of the third type of simulations of L-(left) and D-Phes (right). Water molecules and ions were omitted for the clarity. Charged and three-phenylalanine residues are shown by licorice model. Orange balls show phosphorus atoms of DMPC membrane. Green and yellow balls represent the sodium and chloride ions, respectively. Appl. Sci. 2019, 9, x FOR PEER REVIEW 9 of 16
Secondary structure profiles during the third type of simulations (MD3). Secondary structure profiles during the third type of simulations (MD3).
Information of simulation systems.
Average tilt angle in the last 100 ns simulations (MD3).
L-phenylseptin (L-Phes) and D-phenylseptin (D-Phes) are amphibian antimicrobial peptides isolated from the skin secretion of Hypsiboas punctatus. In the N-termini, L-Phes and D-Phes contain three consecutive phenylalanine residues, l-Phe-l-Phe-l-Phe and l-Phe-d-Phe-l-Phe, respectively. They are known to exhibit antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Xanthomonas axonopodis pv. Glycines. However, their mechanism of action and the role of the D-amino acid residue have not been elucidated yet. In this study, the interactions of both peptides with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were investigated by means of quartz crystal microbalance, circular dichroism, vibrational circular dichroism, 31P solid-state NMR, and molecular dynamics simulation. Both peptides have similar binding constants to the DMPC lipid bilayers, in the order of 106 M−1, and form an α-helix structure in the DMPC lipid bilayers. Both the peptides induce similar changes in the dynamics of DMPC lipids. Thus, in spite of the difference in the conformations caused by the chirality at the N-terminus, the peptides showed similar behavior in the membrane-bound state, experimentally and computationally.
The use of natural rubber to resist bitumen is usually prone to degradation and aging. One method to overcome this problem is the addition of antioxidants. This study aims to determine the effect of the addition of antioxidants 1,2-dihydro-2,2,4-trimethyl-quinoline (TMQ) on natural rubber modified asphalt crepe rubber and its performance in short-term and long-term aging conditions. The modified rubber asphalt mixture’s manufacture begins by melting the crepe rubber at 200 °C before being mixed in asphalt at 165 °C. Addition of antioxidant TMQ during the stirring process of the mixture of asphalt and melted rubber. The crepe rubber content was 8, 10, and 12% w/w, while the TMQ content was 1, 2, and 3% w/w of the total sample weight. The modified asphalt samples’ characterization included penetration, softening point, weight loss after a rolling thin film oven test (RTFOT), penetration after RTFOT, and Marshall test. Review of the performance of asphalt under short-term aging conditions using a dynamic shear rheometer (DSR). Evaluation of asphalt performance under long-term aging conditions using Fourier-transform infrared spectroscopy (FTIR). The results showed that the fact that the best-modified asphalt product was the addition of 10% crepe rubber and 2% TMQ. The best-modified asphalt characteristics have penetration 68.70 dmm, softening point 55.45 °C, weight loss only 0.0579%, penetration after RTFOT 59.60, Marshall stability 1403.96 kg with optimum asphalt content of 5.50%, and rutting factor (G*/Sinδ) 6.91 kPa and 16.1 kPa before and after RTFOT. Overall, the modified crepe rubber asphalt can improve the performance of the asphalt in terms of durability. Simultaneously, the antioxidant TMQ works very well in increasing the resistance of bitumen to aging in the conditions of short-term aging and long-term aging.
Charge and discharge curves of graphite negative electrode in (a) PLD310, (b)
Raman spectra of (a) PC, (b) DCE, (c) PC/DCE = 3:1 (molar ratio), (d) PC/LiPF6 =
Physical properties of electrolyte solutions. DCE: 1,2-dichloroethane; PC: propylene carbonate.
In concentrated propylene carbonate (PC)-based electrolyte solutions, reversible lithium intercalation and de-intercalation occur at graphite negative electrodes because of the low solvation number. However, concentrated electrolyte solutions have low ionic conductivity due to their high viscosity, which leads to poor electrochemical performance in lithium-ion batteries. Therefore, we investigated the effect of the addition of 1,2-dichloroethane (DCE), a co-solvent with low electron-donating ability, on the electrochemical properties of graphite in a concentrated PC-based electrolyte solution. An effective solid electrolyte interphase (SEI) was formed, and lithium intercalation into graphite occurred in the concentrated PC-based electrolyte solutions containing various amounts of DCE, while the reversible capacity improved. Raman spectroscopy results confirmed that the solvation structure of the lithium ions, which allows for effective SEI formation, was maintained despite the decrease in the total molality of LiPF6 by the addition of DCE. These results suggest that the addition of a co-solvent with low electron-donating ability is an effective strategy for improving the electrochemical performance in concentrated electrolyte solutions.
Scheme 9. I2/CuCl2 mediated catalysis for the construction of thiadiazoles (53).
Scheme 9. I 2 /CuCl 2 mediated catalysis for the construction of thiadiazoles (53).
Scheme 10. Synthesis of acrylamide derivatives of thiadiazoles (59).
The 1,2,3-thiadiazole moiety occupies a significant and prominent position among privileged heterocyclic templates in the field of medicine, pharmacology and pharmaceutics due to its broad spectrum of biological activities. The 1,2,3-thiadiazole hybrid structures showed myriad biomedical activities such as antifungal, antiviral, insecticidal, antiamoebic, anticancer and plant activators, etc. In the present review, various synthetic transformations and approaches are highlighted to furnish 1,2,3-thiadiazole scaffolds along with different pharmaceutical and pharmacological activities by virtue of the presence of the 1,2,3-thiadiazole framework on the basis of structure–activity relationship (SAR). The discussion in this review article will attract the attention of synthetic and medicinal researchers to explore 1,2,3-thiadiazole structural motifs for future therapeutic agents.
Commonly used antimicrobial agents with hydrazide-hydrazone scaffold.
The antimicrobial activity assay results for compounds 2-16.
The RM0 values of the synthesized 4-methyl-1,2,3-thiadiazole-5-carbooxylic acid deriva- tives (2-6 and 8-16).
Bacterial infections, especially those caused by strains resistant to commonly used antibiotics and chemotherapeutics, are still a current threat to public health. Therefore, the search for new molecules with potential antimicrobial activity is an important research goal. In this article, we present the synthesis and evaluation of the in vitro antimicrobial activity of a series of 15 new derivatives of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid. The potential antimicrobial effect of the new compounds was observed mainly against Gram-positive bacteria. Compound 15, with the 5-nitro-2-furoyl moiety, showed the highest bioactivity: minimum inhibitory concentration (MIC) = 1.95–15.62 µg/mL and minimum bactericidal concentration (MBC)/MIC = 1–4 µg/mL.
Top-cited authors
Danial Jahed Armaghani
  • University of Technology Sydney
Panagiotis G. Asteris
  • School of Pedagogical & Technological Education
Jian Zhou
  • Central South University
Francesco Tornabene
  • Università del Salento
Hoang Nguyen
  • Hanoi University of Mining and Geology