Tao Hu

China Academy of Chinese Medical Sciences, Peping, Beijing, China

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Publications (80)237.35 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: [100] is believed to be a tough diffusion direction for Li(+) in LiFePO4, leading to the belief that the rate performance of [100]-oriented LiFePO4 is poor. Here we report the fabrication of 12-nm-thick [100]-oriented LiFePO4 nanoflakes by a simple one-pot solvothermal method. The nanoflakes exhibit unexpectedly excellent electrochemical performance, in stark contrast to what was previously believed. Such an exceptional result is attributed to a decreased thermodynamic transformation barrier height (Δμb) associated with increased active population.
    No preview · Article · Dec 2015 · Nano Letters
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    ABSTRACT: Structure and vibrational dynamics of T-terminated titanium carbide monosheets Ti2CT2 (T = O, F, OH) are studied by means of first-principles calculations to understand their inherent relation. Terminations modulate the crystal structures through the redistribution of valence electron density among the atoms in the monosheets, particularly Ti atoms. Phonon partial density of states analysis shows a clear feature of collaborative vibration, which reflects the covalent nature of bonds in the monosheets. Two metrics of covalency and cophonicity proposed very recently are adopted to quantitatively correlate the vibrational properties with the electro-structural characteristics of the system. A remarkable positive correlation between the covalency and vibrational dynamics specified as Raman shifts and IR wavenumbers is found. The bond-specific covalency metrics depend on not only the identity of terminations but also the thickness of the two-dimensional titanium carbides. For example, in the case of Ti3C2T2 with increased thickness, red shift in Raman shifts and IR wavenumbers occurs as a result of the decrease in covalency.
    No preview · Article · Dec 2015 · The Journal of Physical Chemistry A
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    ABSTRACT: Stacked two-dimensional titanium carbide is an emerging conductive material for electrochemical energy storage which requires an understanding of the intrinsic electronic conduction. Here we report the electronic conduction properties of stacked Ti3C2T2 (T = OH, O, F) with two distinct stacking sequences (Bernal and simple hexagonal). On the basis of first-principles calculations and energy band theory analysis, both stacking sequences give rise to metallic conduction with Ti 3d electrons contributing most to the conduction. The conduction is also significantly anisotropic due to the fact that the effective masses of carriers including electrons and holes are remarkably direction-dependent. Such an anisotropic electronic conduction is evidenced by the I−V curves of an individual Ti3C2T2 particulate, which demonstrates that the in-plane electrical conduction is at least one order of magnitude higher than that vertical to the basal plane.
    Full-text · Article · Nov 2015 · Scientific Reports
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    ABSTRACT: The conventional wisdom to tailor the properties of binary transition metal carbides by order-disorder phase transformation has been inapplicable for the machinable ternary carbides (MTCs) due to the absence of ordered phase in bulk sample. Here, the presence of an ordered phase with structural carbon vacancies in Nb4AlC3-x (x ≈ 0.3) ternary carbide is predicted by first-principles calculations, and experimentally identified for the first time by transmission electron microscopy and micro-Raman spectroscopy. Consistent with the first-principles prediction, the ordered phase, o-Nb4AlC3, crystalizes in P63/mcm with a = 5.423 Å, c = 24.146 Å. Coexistence of ordered (o-Nb4AlC3) and disordered (Nb4AlC3-x) phase brings about abundant domains with irregular shape in the bulk sample. Both heating and electron irradiation can induce the transformation from o-Nb4AlC3 to Nb4AlC3-x. Our findings may offer substantial insights into the roles of carbon vacancies in the structure stability and order-disorder phase transformation in MTCs.
    Full-text · Article · Sep 2015 · Scientific Reports
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    ABSTRACT: Binder-free MXene films comprising Ti3C2Tx nanoflakes in a face-to-face fashion, achieved by a simple dropping-mild baking approach, exhibit high gravimetric capacitances up to 499 F/g with excellent cyclability and rate performances. The entire electrodes including Ni-foam and MXene film show volumetric capacitances in the range of 84-226 F/cm3 depending on the loadings of MXene as active material.
    Full-text · Article · Jul 2015 · Chemical Communications
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    ABSTRACT: The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plants at 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4 sigma significance with six years of running. The measurement of antineutrino spectrum will also lead to the precise determination of three out of the six oscillation parameters to an accuracy of better than 1\%. Neutrino burst from a typical core-collapse supernova at 10 kpc would lead to ~5000 inverse-beta-decay events and ~2000 all-flavor neutrino-proton elastic scattering events in JUNO. Detection of DSNB would provide valuable information on the cosmic star-formation rate and the average core-collapsed neutrino energy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400 events per year, significantly improving the statistics of existing geoneutrino samples. The JUNO detector is sensitive to several exotic searches, e.g. proton decay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe.
    Full-text · Article · Jul 2015
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    ABSTRACT: An attenuated Bacillus anthracis vaccine strain for human use, A16R, was obtained in China after ultraviolet radiation treatment and continuous subculture of the wild-type strain A16. A16R can synthesize the exotoxin, but without a capsule. We sequenced and annotated the A16R genome to encourage the use of this strain. The genome sequencing of the wild-type strain A16 is underway and the genomic comparison between the two strains will help to illustrate the attenuating mechanism of the A16R vaccine strain. Copyright © 2015. Published by Elsevier B.V.
    Preview · Article · Jun 2015 · Journal of Biotechnology
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    ABSTRACT: Neisseria meningitidis can cause severe and fulminant diseases such as meningitis. Meningococcal capsular polysaccharide (PS) is a key virulence determinant that is not able to induce immunological memory. Conjugation of PS to a carrier protein can significantly increase the immunogenicity of PS and induce immunological memory. Due to the classically described carrier-induced epitopic suppression (CIES) mechanisms, a strong immune response against the carrier protein could suppress the immune response to PS after coadministration of free carrier protein with the conjugate vaccine. However, it was not clear whether suppressing or enhancing the protein-specific immunogenicity could improve the PS-specific immunogenicity of the conjugate vaccine. Thus, moderate PEGylation, extensive PEGylation and oligomerization were used to regulate the immunogenicity of tetanus toxoid (TT) in the conjugate vaccine (PS-TT). Moderate PEGylation led to a 2.7-fold increase in the PS-specific IgG titers elicited by PS-TT. In contrast, extensive PEGylation and oligomerization of TT led to 1.4-fold and 1.6-fold decrease in the PS-specific IgG titers elicited by PS-TT, respectively. The PS-specific immunogenicity of PS-TT can be increased by moderate PEGylation through mild suppression of the TT-specific immunogenicity. The PS-specific immunogenicity of PS-TT was decreased through significant suppression or enhancement of the TT-specific immunogenicity. Thus, our study contributes to understand the CIES mechanisms and improve the PS-specific immunogenicity of a meningococcal PS conjugate vaccine. Copyright © 2015. Published by Elsevier Ltd.
    No preview · Article · May 2015 · Vaccine
  • Ling Wu · Shaoyang Ji · Tao Hu
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    ABSTRACT: Human growth hormone (hGH) has been used to treat children with short stature, renal failure and Turner's Syndrome. However, clinical application of hGH suffers from its short plasma half-life and low bioavailability. PEGylation and albumin binding are two of the most effective approaches to prolong the plasma half-life of hGH. However, the steric shielding effects of polyethylene glycol (PEG) and albumin can drastically decrease the bioactivity of hGH, which is opposite to the increased pharmacokinetics (PK). In the present study, a long-acting hGH with markedly improved pharmacological profile was rationally designed and prepared by N-terminal modification of hGH with pseudo bifunctional PEG-hexadecane, using PEG (3.5 kDa or 10 kDa) as the linker. PEGylation and albumin binding with hexadecane can increase the hydrodynamic volume and decrease the immunogenicity of hGH, thereby markedly increasing the PK of hGH. Since N-terminus is far from the bioactive domain of hGH, N-terminal modification of hGH can minimize the steric shielding effects on the bioactive domain of hGH. Hexadecane-bound albumin can be slowly released from hGH during the in vivo circulation, which can slowly restore the bioactivity of hGH. Thus, the high bioactivity of PEG-hexadecane modified hGH (hGH-PEG-HD) was synergistically achieved by N-terminal modification with pseudo bifunctional PEG-hexadecane and slow-release of albumin. The high pharmacodynamics (PD) of hGH-PEG-HD was due to the synergistic effect of the high bioactivity and the overall increased PK.
    No preview · Article · Apr 2015 · Molecular Pharmaceutics
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    ABSTRACT: We present a comparative study on the static and dynamical properties of bare Ti3C2 and T-terminated Ti3C2T2 (T = O, F, OH) monosheets using density functional theory calculations. First, the crystal structures are optimized to be of trigonal configurations (P3[combining macron]m1), which are thermodynamically and dynamically stable. It is demonstrated that the terminations modulate the crystal structures through valence electron density redistribution of the atoms, particularly surface Ti (Ti2) in the monosheets. Second, lattice dynamical properties including phonon dispersion and partial density of states (PDOS) are investigated. Phonon PDOS analysis shows a clear collaborative feature in the vibrations, reflecting the covalent nature of corresponding bonds in the monosheets. In the bare Ti3C2 monosheet, there is a phonon band gap between 400 and 500 cm(-1), while it disappears in Ti3C2O2 and Ti3C2(OH)2 as the vibrations associated with the terminal atoms (O and OH) bridge the gap. Third, both Raman (Eg and A1g) and infrared-active (Eu and A2u) vibrational modes are predicted and conclusively assigned. A comparative study indicates that the terminal atoms remarkably influence the vibrational frequencies. Generally, the terminal atoms weaken the vibrations in which surface Ti atoms are involved while strengthening the out-of-plane vibration of C atoms. Temperature-dependent micro Raman measurements agree with the theoretical prediction if the complexity in the experimentally obtained lamellae for the Raman study is taken into account.
    Full-text · Article · Mar 2015 · Physical Chemistry Chemical Physics
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    ABSTRACT: Meningococcal disease is a fatal illness of sudden onset caused by Neisseria meningitides. Meningococcal capsular polysaccharide (CPS) is a major virulence factor that generally does not induce immunological memory. Conjugation with a carrier protein can significantly increase the immunogenicity of CPS and induce immunological memory. However, it is highly desired to optimize the CPS-specific immunogenicity of the conjugate vaccine. Although adjuvant has been widely used to improve the immunogenicity of antigens, co-administration and conjugation of adjuvant with the conjugate vaccine has rarely been investigated. As a stimulator of humoral and cellular immunity, β-glucan can activate macrophages and trigger intracellular processes to secrete cytokines initiating inflammatory reactions. In the present study, a conjugate vaccine (CPS-TT) was generated by conjugation of tetanus toxoid (TT) with meningococcal group Y CPS. CPS-TT was further conjugated with β-glucan to generate CPS-TT-G. Immunization with CPS-TT-G led to an 8.2-fold increase in the CPS-specific IgG titers as compared with CPS-TT. Presumably, conjugation of β-glucan ensured the two components to simultaneously reach the antigen presenting cells and stimulate the immune response. In contrast, co-administration of β-glucan suppressed the CPS-specific immunogenicity of CPS-TT. Thus, conjugation of β-glucan is an effective strategy to markedly improve the CPS-specific immunogenicity of the conjugate vaccine. Copyright © 2015. Published by Elsevier Ltd.
    No preview · Article · Feb 2015 · Vaccine
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    ABSTRACT: Due to its high twin boundary energy, the absence of Σ3{112} in covalently bonded TiC has been theoretically adjudged. Here, we report the observation of TiC twin boundaries that consist of Σ3{112} and Σ3{111} steps in a faceted and inclined manner. The twin interface in the transition region is not flat, wherein periodic contrasts resulting from overlapped twins were identified. Based on the microstructural analyses, a formation mechanism for the energy-expensive Σ3{112} and inclined twin boundaries is elaborated.
    Full-text · Article · Feb 2015 · Journal of the American Ceramic Society
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    ABSTRACT: High-Tc superconductors confined to two dimension exhibit novel physical phenomena, such as superconductor-insulator transition. In the Bi2Sr2CaCu2O8+x (Bi2212) model system, despite extensive studies, the intrinsic superconducting properties at the thinness limit have been difficult to determine. Here, we report a method to fabricate high quality single-crystal Bi2212 films down to half-unit-cell thickness in the form of graphene/Bi2212 van der Waals heterostructure, in which sharp superconducting transitions are observed. The heterostructure also exhibits a nonlinear current-voltage characteristic due to the Dirac nature of the graphene band structure. More interestingly, although the critical temperature remains essentially the same with reduced thickness of Bi2212, the slope of the normal state T-linear resistivity varies by a factor of 4-5, and the sheet resistance increases by three orders of magnitude, indicating a surprising decoupling of the normal state resistance and superconductivity. The developed technique is versatile, applicable to investigate other two-dimensional (2D) superconducting materials.
    Full-text · Article · Dec 2014 · Nature Communications
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    ABSTRACT: The interplay between unconventional superconductivity and the ordering of charge/spin density wave is one of the most vital issues in both condensed matter physics and material science. The Ti-based compound BaTi2As2O, which can be seen as the parent phase of superconducting BaTi2Sb2O, has a layered structure with a space group P4/mmm, similar to that of cuprate and iron-based superconductors. This material exhibits a charge density wave (CDW) ordering transition revealed by an anomaly at around 200 K in transport measurements. Here, we report the synthesis and systematical study of the physical properties in Cr-doped BaTi2-xCrxAs2O (x = 0-0.154) and demonstrate that the transition temperature of the CDW ordering is suppressed gradually by the doped Cr element. The magnetization measurements confirm the evolution of the CDW ordering transition. These observed behaviors are similar to that observed in iron-based superconductors, but no superconductivity emerges down to 2 K. In addition, the first-principles calculations are also carried out for well-understanding the nature of experimental observations.
    Full-text · Article · Dec 2014 · Inorganic Chemistry
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    ABSTRACT: The search for exotic materials with a linear Dirac-like dispersion in the electronic structure is one of the most challenging tasks of the condensed matter community and materials science. Revealing the nature of the interplay between such a Dirac-like and superconducting states is a crucial issue for the study of fundamental physics. Here we report the experimental observations of a large linear magnetoresistance (MR) in the Ca-intercalated graphite superconductor ${\mathrm{CaC}}_{6}$. A large nonsaturating MR with a magnitude as high as 244% is observed at low temperature under a magnetic field of 9 T. The magnetic field $(B)$ dependence of MR shows a linear behavior above 3 T at low temperature, which deviates from the classical ${B}^{2}$ behavior, pointing to the existence of an intrinsic linear Dirac-like state. The presence of such a low-energy Dirac-like dispersion in energy band structure is confirmed qualitatively by performing first-principles calculations. These findings may pave an avenue for potential applications in magnetoelectronic sensors and for further studying the interplay between the linear Dirac-like and superconducting states in exotic materials.
    Full-text · Article · Dec 2014 · Physical Review B
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    ABSTRACT: In this work, we study the response of single layer Thick GEM (THGEM) detector to p/${\pi^+}$ at E3 line of Beijing Test Beam Facility. In our experiment, the drift gap of THGEM Detector is 4mm, and the working gas is Ar/3% iso. Result shows at the momentum 500MeV/c to 1000MeV/c, detection efficiency for p is from 93% to 99% in a relatively lower gain($\sim$2000), while the detection efficiency for ${\pi^+}$ is slightly lower than that for p, which is from 82% to 88%. Meanwhile, simple Geant4 simulations have been done, and results of beam test are almost consistent with it. We preliminarily study the feasibility of THGEM detectors as sampling elements for Digital Hadronic Calorimeter(DHCAL), which may provide related reference for THGEM possibly applied in Circular Electron Positron Collider(CEPC) HCAL.
    Full-text · Article · Nov 2014
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    ABSTRACT: High-purity germanium detectors are well suited to analysis the radioactivity of samples. In order to reduce the environmental background, low-activity lead and oxygen free copper are installed outside of the probe to shield gammas, outmost is a plastic scintillator to veto the cosmic rays, and an anti-Compton detector can improve the Peak-to-Compton ratio. Using the GEANT4 tools and taking into account a detailed description of the detector, we optimize the sizes of the detectors to reach the design indexes. A group of experimental data from a HPGe spectrometer in using were used to compare with the simulation. As to new HPGe Detector simulation, considering the different thickness of BGO crystals and anti-coincidence efficiency, the simulation results show that the optimal thickness is 5.5cm, and the Peak-to-Compton ratio of 40K is raised to 1000 when the anti-coincidence efficiency is 0.85. As the background simulation, 15 cm oxygen-free copper plus 10 cm lead can reduce the environmental gamma rays to 0.0024 cps/100 cm3 Ge (50keV~2.8MeV), which is about 10-5 of environmental background.
    Preview · Article · Oct 2014 · Chinese Physics C
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    ABSTRACT: Epitaxial BaTiO3(BTO)/LaAlO3(LAO) heterostructure films were fabricated on TiO2-teminated SrTiO3(STO) substrates by pulsed laser deposition. The oxygen pressure effects during the growth of ferroelectric BTO overlayers on top of the LAO/STO structures with two dimensional electron gas (2DEG) were investigated. An obvious influence on the crystalline structure and microstructural characteristics was observed via X-ray diffractometry and atomic force microscopy. In addition, the interfacial sheet resistance measurements were carried out for those heterostructures with and without BTO overlayers. The results indicate that the LAO/STO interface is insulating state above oxygen pressure of 2.5 Pa, which could however be tuned to conducting state through integrating ferroelectric BTO film into the LAO/STO 2DEG system.
    No preview · Article · Sep 2014 · Ceramics International
  • Ling Wu · Shaoyang Ji · Lijuan Shen · Tao Hu
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    ABSTRACT: Human growth hormone (hGH) suffers from a short plasma half-life of ~15 min, necessitating frequent injections to maintain its physiological effect. PEGylation, conjugation of polyethylene glycol (PEG) is an effective strategy to prolong the plasma half-life of hGH. However, PEGylation can significantly decrease the bioactivity of hGH. Thus, a new PEGylation approach is desired to improve the pharmacokinetics (PK) and pharmacodynamics (PD) of the PEGylated hGH. In the present study, two N-terminally mono-PEGylated hGHs were prepared using aldehyde chemistry. Phenyl amide and ethyl moieties were used as the linkers between PEG and hGH, respectively. The hydrodynamic volume, proteolytic sensitivity and immunogenicity of the PEGylated hGH with phenyl amide linker (hGH-phenyl-PEG) were lower than those of the one with propyl linker (hGH-prop-PEG). In addition, hGH-phenyl-PEG showed a higher in vitro bioactivity and better PK and PD than hGH-prop-PEG. The better PK of hGH-phenyl-PEG was mainly due to its lower proteolytic sensitivity and low immunogenicity. The better PD of hGH-phenyl-PEG was mainly due to its higher in vitro bioactivity. Thus, the phenyl amide linker can improve the overall pharmacological profiles of the PEGylated hGH. Our study is expected to advance the development of long-acting protein biotherapeutics with high therapeutic efficacy.
    No preview · Article · Aug 2014 · Molecular Pharmaceutics
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    ABSTRACT: The transport properties, phase diagram, and dopant distribution are investigated in systematically Nd doped CaFe_2As_2 single crystals. Coexistence of two superconducting (SC) phases with different critical transition temperature (T_c) is observed. The low-T_c phase emerges as x >= 0.031, and the T_c value increases to its maximum value of about 20 K at x = 0.083, the maximum doping level in our study. As x >= 0.060, the high-T_c phase with a T_c value of about 40 K is observed. The structure transition (STr) from tetragonal to orthorhombic phase vanishes suddenly around x = 0.060, where a new STr from tetragonal to collapsed tetragonal phase begins to turn up. Compared to the low-T_c phase, the end point of SC transition of the high-T_c phase is more sensitive to the magnetic field, showing a characteristic of Josephson weak-link behavior. Possible scenarios about this system are discussed based on our observations. We also find that the non-uniform SC properties cannot be attributed to the heterogeneous Nd distribution on the micro scale, as revealed by the detailed energy dispersive X-ray spectroscopy (EDS) measurements.
    Preview · Article · Aug 2014 · New Journal of Physics

Publication Stats

458 Citations
237.35 Total Impact Points

Institutions

  • 2015
    • China Academy of Chinese Medical Sciences
      Peping, Beijing, China
  • 2009-2015
    • Beijing Genomics Institute
      Bao'an, Guangdong, China
  • 2002-2015
    • Chinese Academy of Sciences
      • • State Key Laboratory of Biochemical Engineering
      • • Institute of Process Engineering
      Peping, Beijing, China
  • 2013-2014
    • Shanghai Institute of Microsystem And Information Technology
      Shanghai, Shanghai Shi, China
  • 2012-2014
    • Dalian University of Technology
      • School of Materials Science and Engineering
      Lü-ta-shih, Liaoning, China
  • 2010-2014
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 2012-2013
    • University of Science and Technology of China
      Luchow, Anhui Sheng, China
  • 2011-2012
    • Southwest University in Chongqing
      Pehpei, Chongqing Shi, China
  • 2010-2012
    • Institute of physics china
      Peping, Beijing, China
  • 2006-2011
    • Albert Einstein College of Medicine
      • • Department of Physiology & Biophysics
      • • Department of Biochemistry
      New York, New York, United States