Zhaohui Zhang

Zhaohui Zhang
University of Science and Technology Beijing | USTB · Department of Instrumentation Science

Doctor of Philosophy

About

52
Publications
1,808
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
152
Citations

Publications

Publications (52)
Article
The terahertz (THz) region has much appeal for differentiating between hydrate systems and for physically characterizing pharmaceutical drug materials. The present study employs THz absorption spectroscopy to investigate the effect of heating on dehydration and hydration in α-lactose monohydrate. Distinctive THz absorption spectra were observed fol...
Article
Internet of Things (IoT) is a highly integrated and comprehensive information technology that is currently a research hotspot. However, it presents many challenges; e.g., the use of multiple products in one IoT can lead to incompatible communication. It is imperative to solve the problem of communication protocol heterogeneity. In this study, a mul...
Article
Nuclear energy is a clean and popular form of energy, but leakage and loss of nuclear material pose a threat to public safety. Radiation detection in public spaces is a key part of nuclear security. Common security cameras equipped with complementary metal oxide semiconductor (CMOS) sensors can help with radiation detection. Previous work with thes...
Article
Gait recognition is a biometric identification method that can be realized under long-distance and no-contact conditions. Its applications in criminal investigations and security inspections are thus broad. Most existing gait recognition methods adopted the gait energy image (GEI) for feature extraction. However, the GEI method ignores the dynamic...
Article
Terahertz (THz) time-domain spectroscopy provides a direct and nondestructive method for measuring the dielectric properties of materials directly from the phase delay of coherent electromagnetic radiation propagating through the sample. In cases when crystals are embedded within an inert polymeric pellet, the Landau, Lifshitz, and Looyenga (LLL) e...
Article
Full-text available
In this paper, we present the application of transmissive terahertz (THz) time-domain spectroscopy for determining molecular polarizability for three widely applied solvents: water, ethanol, and acetone. Molecular polarizabilities of those solvents are obtained from the refractive index by using the Lorentz-Lorenz equation. The measured THz molecul...
Article
Full-text available
Terahertz (THz) transmission spectroscopy is widely used to obtain spectra of materials by measuring the electric field of a THz pulse in the time domain. However, time-domain waveforms are easily influenced by the surface roughness, which generates random noise and reduces the detection reliability. In this paper, we target the problem of roughnes...
Article
Full-text available
Given the condition that protein conformation and activity are highly susceptible to environment factors such as temperature and pH, evaluation of protein conformation and activity is urgently needed in many fields. For example, most protein drugs need a stable and proper environment during production, storage and transportation, and it’s an enormo...
Article
Nuclear technology is being promoted and applied worldwide but poses a certain threat to public safety, thus necessitating nuclear radiation detection. In addition to the use of dedicated instruments, the use of surveillance cameras with complementary metal oxide semiconductor (CMOS) sensors is a promising direction for nuclear radiation detection....
Article
NaI(Tl) spectrometry is widely used in many areas for gamma-ray detection. It can be used for both activity measurement and isotope identification. However, the light generation of NaI(Tl) and photomultiplier tube (PMT) is sensitive to temperature changes, which lead to spectrum shift. Several calibration methods have been proposed, but they are co...
Article
Abandoned objects in a road can be a potential threat to urban traffic. In this article we present a new threat degree analysis method of abandoned objects, which is based on dynamic multifeature fusion to detect the abandoned objects and analyze the threat degree automatically. The image sequence is acquired with a visible sensor installed at over...
Article
With simulation of absorption spectra in THz region based on quantum-chemical calculation, the THz absorption features of target materials can be assigned with theoretical normal vibration modes. This is necessary for deeply understanding the origin of THz absorption spectra. The reliabilities of simulation results mainly depend on the initial stru...
Conference Paper
This paper proposed an embedded system to acquire and storage images periodically based on STM32 and transmit images with GPRS to monitoring center. Monitoring center can also send command to acquisition terminals over GPRS. Acquisition terminals are based on STM32 characterized by low energy consumption and high performance. Experiments showed acq...
Article
According to ISA100.11a standard, a new gateway access method based on application layer was proposed in this paper which realized the communication between wireless sensor networks and Ethernet. It was C/S structure and completed on the Linux operating development platform. The system mainly contained four modules: Ethernet interface module, data...
Article
Full-text available
The qualitative and quantitative analysis of amino acids by terahertz (THz) refractive index spectra is discussed. The frequency band of anomalous dispersion emerging in the spectra is unique for the amino acids, L-glutamine (Gln) and L-histidine (His). The refractive indices of the amino acids were found to be linearly proportional to the concentr...
Article
In this paper, we used terahertz time-domain spectroscopy (THz-TDS) over a range of 0.3–2.5 THz to investigate the formation of solid-state cocrystals of amino acids, formed by grinding mixtures of two different kinds of amino acids. For comparison, we prepared dual-layer samples, combined by pressing two single-component pellets together without g...
Article
Using THz-TDS to extract the absorption spectrum of a sample is an important branch of various THz applications. Basically, we believe that the THz radiation scatters from sample particles, leading to an obvious baseline increasing with frequencies in its absorption spectrum. The baseline will affect the measurement accuracy due to ambiguous height...
Article
The present paper discusses the Lambert-Beer' s law application in the terahertz spectrum, studies the single amino acid tablet sample (glutamine) and two kinds of amino acids mixture tablet (threonine and cystine) under the condition of different concentrations. Absorbance and absorption coefficient was analyzed in the description of the terahertz...
Article
Identification of specific materials is one of the most promising THz applications. It is commonly achieved by comparing the experimental peak central frequencies of the transmission or absorption spectra with a database for known materials while neglecting the linewidths. However, due to the restriction of the signal-to-noise ratio, only a narrow...
Conference Paper
According to the characteristics of small and medium-sized greenhouse environmental monitoring, this paper proposes a solution to remote greenhouse environmental monitoring which is based on GSM technology and RF. The system constitutes the regional environmental information monitoring network and close communication platform based on radio frequen...
Article
Using THz-TDS to detect the THz temporal pulse and calculate the absorption spectrum of the sample is the main access to qualitative and quantitative analysis. The shape and the amplitude of the THz absorption spectra are not only related to the sample, but also closely related to the length of the chosen THz pulse in the calculation, which was dis...
Conference Paper
The baseline of THz absorption spectrum caused by particle scattering is critical to quantitative analysis.By mitigating scattering effects using Kaushik’s approach,the accuracy of calculated component concentrations of a mixture sample was improved.
Conference Paper
Obtaining accurate terahertz absorption spectra is critical to quantitative analysis. By correcting the spectra of amino acids using Kaushik’s approach, the accuracy of calculated component concentrations of a mixture sample was improved.
Conference Paper
Wireless based data acquisition solutions are widely used in many fields like structure monitoring, transportation or environmental studies. This paper presents a General Packet Radio Service (GPRS) based remote data acquisition and forecasting system, which monitors the geological disasters along the natural gas pipeline under the ground. The fiel...
Article
The terahertz absorption spectrum has a complex nonlinear relationship with sample thickness, which is normally measured mechanically with limited accuracy. As a result, the terahertz absorption spectrum is usually determined incorrectly. In this paper, an iterative algorithm is proposed to accurately determine sample thickness. This algorithm is i...
Article
Terahertz (THz) absorption spectra have been applied to measure the compositions of amino acid samples. Because the concentration information about a specific composition is involved in its spectrum, keeping the spectrum length and dynamic range as wide as possible is essential for precise measurements. It is well known that a spectrum is always co...
Article
Extracting absorption spectrum in THz band is one of the important aspects in THz applications. Sample's absorption coefficient has a complex nonlinear relationship with its thickness. However, as it is not convenient to measure the thickness directly, absorption spectrum is usually determined incorrectly. Based on the method proposed by Duvillaret...
Article
The key point to measure a sample and to carry out its absorption spectrum is that the whole test process is completed in very stable situations. Although the distributed setup of THz-TDS is flexible to implement kinds of experiments, slightly displacements of mirrors may occur in the system. A typical kind of disturbance exists in the system due t...
Article
Quantitative measurement based on THz absorption spectrum is of great importance in THz applications. Several researchers have worked on it and gained some achievements, but most of them explored pure component or no more than 2-component s samples. In this paper, a mixture sample consisting of Glutamine, Histidine and Threonine is investigated in...
Article
Full-text available
An underpinning software is devoted to THz spectrum analyzing and 3-D imaging. The paper describes the software's outline, structure, functions and some of considerations. Users in LAN (local area network) can access it and implement some basic and advanced works such as files operation, echoes cutting, spectrum calculation, baseline cancelling, pe...
Article
To address the problem of poor robustness of pupil tracking in infrared images for gaze tracking systems, this paper presents a particle filter algorithm for pupil tracking based on pseudo-color map. This paper also presents a concept of triple-channel pseudo-color map (TCPCM) by use of the phenomena of bright and dark pupil and leads it into pupil...
Article
For several common drawbacks of existing gaze tracking systems using single camera and single light source: Low accuracy, restricted head movement and tedious calibration, this paper presents a novel gaze tracking method based on pupil center cornea reflection (PCCR) technique. Pupil location for gaze tracking has been well investigated and all met...
Article
In this paper, image multi-scale edge detection based on anti-symmetrical biorthogonal wavelet reconstruction is given detailedly in theory, namely convolution operation property of the anti-symmetrical biorthogonal wavelet transform, is deduced and its differential operator function is analyzed. Then, an algorithm of wavelet decomposition in which...
Article
Parallel flatness pattern recognition based on a binary tree hierarchical back propagation (BP) model and Legendre orthodoxy polynomial decomposition was presented aiming at the illegibility in physical meaning and poorness in robust stability of traditional flatness defect pattern recognition by the least squares method (LSM) proximity algorithm a...
Article
To improve the hot rolled strip quality and operational stability, a novel tensionmeter based on lever principle is developed which inspects latent waves and provides real references for flatness control in hot rolling process. The contact-type tensionmeter including two segmented rolls can get the transverse tension distribution along the strip wi...
Article
In order to overcome the weakness of traditional flatness defect pattern recognition by least squares method (LSM) proximity algorithm which is illegible on physical meaning and poor robust stability, as long as the low accuracy of common BP neuron network, a novel parallel flatness defect pattern recognition model based on binary tree hierarchical...
Conference Paper
Pipeline transportation, as it is low cost, steady supply and high efficiency, is widely used nowadays. However, pipelines might be damaged by natural power or human activities. Thus, pipeline status monitoring, including transmogrification, corrosion, flaw and crack, shows up more and more important. This paper presents a method using magnetic fie...
Conference Paper
For the purpose of better application, the nonlinear correction of the transducer is very important. In this paper, the nonlinear correction system for the thermal resistance transducer is researched to realize the nonlinear correction. The system consists of five parts including the thermal resistance transducer, the amplifying circuit, AD convert...
Article
This paper presents a novel application of MEMS accelerometer in target classification by means of advanced information processing. The detection system based on MEMS accelerometer is small in size, light in weight, has low power consumption and low cost, and can work under severe circumstances for many different applications. In order to extract f...
Conference Paper
This paper researches acoustic signals of typical vehicle targets in order to extract features and to recognize vehicle targets. As a data fusion method, the technique of artificial neural networks combined with genetic algorithm (ANNCGA) is applied for recognition of acoustic signals that belong to different kinds of vehicle targets. The technique...

Network

Cited By