Search Results - (Author, Cooperation:X. Qiu)

2018-05-15

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

2018-03-06

The American Society for Pharmacology and Experimental Therapeutics

0022-3565

1521-0103

Medicine

2018-09-27

Institute of Physics Publishing (IOP)

1748-0221

Physics

2018-03-29

The Company of Biologists

0950-1991

1477-9129

Biology

Chromatin & epigenetics

2012-07-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2013-09-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2015-11-07

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Basic Helix-Loop-Helix Transcription Factors/genetics ; Cyclic Nucleotide-Gated Cation Channels/genetics ; *Gene Expression Regulation, Developmental ; Genetic Loci ; Genetic Markers ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells/*metabolism ; Neurogenesis/*genetics ; Olfactory Mucosa/innervation ; Olfactory Receptor Neurons/*metabolism ; Receptors, Odorant/*genetics ; Sequence Analysis, RNA ; Single-Cell Analysis ; Smell/*genetics ; Transcriptome

2016-04-21

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Bacterial Proteins/*chemistry/*metabolism ; CRISPR-Associated Proteins/*chemistry/*metabolism ; CRISPR-Cas Systems ; Clustered Regularly Interspaced Short Palindromic Repeats/*genetics ; Crystallography, X-Ray ; Firmicutes/*enzymology ; Genetic Engineering ; Models, Molecular ; Nucleic Acid Conformation ; Protein Binding ; Protein Structure, Tertiary ; RNA Stability ; RNA, Bacterial/*chemistry/genetics/*metabolism ; RNA, Guide/chemistry/genetics/metabolism ; Substrate Specificity

2014-01-10

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Core Binding Factor Alpha 2 Subunit/metabolism ; Core Binding Factor beta Subunit/*chemistry/*metabolism ; Crystallography, X-Ray ; Cullin Proteins/*chemistry/*metabolism ; Humans ; Models, Molecular ; Molecular Sequence Data ; Multiprotein Complexes/chemistry/metabolism ; Protein Binding ; Protein Stability ; Protein Structure, Tertiary ; Suppressor of Cytokine Signaling Proteins ; Transcription Factors/chemistry/metabolism ; vif Gene Products, Human Immunodeficiency Virus/*chemistry/*metabolism

2014-08-30

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Animals ; Antibodies, Monoclonal/immunology/*therapeutic use ; Antibodies, Neutralizing/immunology/therapeutic use ; Antibodies, Viral/immunology/*therapeutic use ; Cross Reactions/immunology ; Ebolavirus/immunology ; Enzyme-Linked Immunosorbent Assay ; Female ; Guinea ; Guinea Pigs ; Hemorrhagic Fever, Ebola/blood/*drug therapy/immunology/virology ; *Immunization, Passive ; Macaca mulatta/immunology/virology ; Male ; Molecular Sequence Data ; Sequence Alignment ; Viral Envelope Proteins/chemistry/immunology ; Viremia/drug therapy/immunology/virology

2011-06-02

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Adolescent ; Adult ; Aged ; Antibodies, Viral/blood ; Base Sequence ; Blood/*virology ; Child ; Child, Preschool ; Complement System Proteins/immunology ; DNA Contamination ; DNA, Viral/blood ; Drug Contamination ; Fatigue Syndrome, Chronic/blood/immunology/*virology ; Female ; Humans ; Indicators and Reagents ; Leukemia Virus, Murine/genetics/isolation & purification ; Leukocytes, Mononuclear/*virology ; Male ; Middle Aged ; Molecular Sequence Data ; Polymerase Chain Reaction ; Retroviridae Infections/diagnosis/*virology ; Xenotropic murine leukemia virus-related virus/genetics/immunology/*isolation & ; purification ; Young Adult

1089-7550

AIP Digital Archive

Physics

We have successfully fabricated epitaxially grown YBa2Cu3O7/PrBa2Cu3O7 (YBCO/PBCO) multilayer thin films on SrTiO3 and LaAlO3 substrates by dc/rf magnetron sputtering. The thicknesses of YBCO and PBCO varied from 1 to 8 unit cells. Satellite peaks in x-ray diffraction patterns clearly indicate the formation of periodic modulation structures of different wavelengths. At a certain thickness of the YBCO layer, the zero resistance transition temperature Tc0 decreased with the increase of the PBCO layer thickness. In contrast, Tc0 increased with the increase of the YBCO layer thickness at a constant PBCO layer thickness.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The voltage V versus current I of a high-quality YBa2Cu3O7−x thin film with zero-resistance temperature equal to 90.8 K was measured at temperatures near Tc (85, 87, and 90 K, respectively) under different magnetic fields (0–7 T). A significant result is that the critical-current density of the film reached 1.37×104 A/cm2 (zero field) even at 90 K, implying that strong pinning centers exist in our sample. However, a small applied magnetic field will diminish the critical-current densities remarkably. The pinning-force densities are found to follow Kramer's scaling law in both perpendicular and parallel directions of the magnetic fields to the c axis of the film. A possible influence of thermally activated flux creep on the pinning mechanism is confirmed.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The critical current density Jc(B,T) of epitaxial YBa2Cu3O7−x (YBCO) thin films on LaAlO3 was measured under different applied magnetic fields (0–7 T) with the temperature ranging from 65 to 79 K. At 65 K, the zero-field critical current density of the best film was 5.8×106 A/cm2; even at magnetic fields up to 7 T, Jc could reach as high as 1×106 A/cm2. Strong anisotropy was observed at 79 K. The anisotropy behavior diminished with the decrease of temperature. Experimental results showed that Jc was proportional to (Tc−T)3/2 ; this was in accordance with the theoretical explanation by the Josephson junction model for granular superconductors.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

A new suppression mechanism of turbulent transport, characteristic of the synergism between safety factor and shear flows, is proposed to explain the internal transport barriers (ITBs) observed in neutral-beam-heated tokamak discharges with reversed magnetic shear. It is shown that the evolution of turbulent transport with the strength of the suppression mechanism reproduces the basic features of the formation and development of ITBs observed in experiments. In addition, the present analyses predict the possibility of global ion and electron heat transport barriers. © 2002 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

The trapped electron dynamics is considered in general tokamak magnetic field with positive or reversed shear. Starting from the continuity, energy-evolution, and motion equations of the trapped electron fluid and the definition of Lagrangian invariant, the Lagrangian invariants hidden in the dynamics are strictly found: L=ln[(n/B)c1(T/B2/3)c2], where c1 and c2 are dimensionless changeable parameters and c1∝c2. It yields n/B=const and T3/2/B=const. Further, based on them it is shown that 〈n〉ψq(ψ)=const and 〈T3/2〉ψq(ψ)=const. The former invariant qualitatively fits the experimental data in many tokamaks; the latter may be used to explain the steady-state hollow T-profile (the corresponding hollow j-profile) observed in reversed shear tokamak plasmas. © 2001 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

In this article, a model for anomalous ion heating, a dynamo current-sustained edge toroidal field, and a sawtooth oscillation during the relaxation in the reversed-field pinch (RFP) plasma is presented. The dynamo (α), the turbulent resistivity (β) and viscosity (χ), dependent on the magnetohydrodynamics (MHD) fluctuations, are incorporated into the model. Turbulent viscous dissipation of the fluctuation energy is proposed as the mechanism of the anomalous ion heating. This is a straightforward corollary of the turbulent viscosity heating of ions in that the temperature of the heavier ions is higher than that of the lighter ions and that the ion temperature increases with the MHD fluctuation level. Correspondingly, the turbulent resistivity heats electrons anomalously. It is shown that the dynamo current, generated by the back-transfer of fluctuating magnetic field helicity to mean magnetic field, sustains the RFP magnetic configuration. In the edge the total current density is approximately equal to the dynamo current density, while at the core the dynamo current opposes the applied electric-field-driven current, flattening the current profile. Provided the α dynamo has a periodic behavior in time, the physical quantities of the RFP plasma have a sawtooth time dependence. The local poloidal current density in the edge increases during the sawtooth crash and peaks at the end of the crash, as do the ion and electron temperatures. In contrast, the toroidal current density at the core decreases during the crash and arrives at its minimum at the end of the crash. Qualitatively, the conclusions drawn from the present model are in good agreement with many of the experimental results [Scime et al., Phys. Rev. Lett. 68, 2165 (1992); Ji et al., ibid. 73, 668 (1994)] and the numerical simulations. © 1996 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

In this paper, a model for the kinetic Alfvén wave (KAW) in the presence of fusion alphas is established. The finite-β (relative to low β) and alpha particle effects on KAW are investigated. In this model, ion sound, transit time magnetic pumping (TTMP), the response of alpha particles (alphas), and those effects considered by preceding authors are included. In cylindrical geometry, a set of three second-order differential equations in r for the perturbed fields Er, E⊥, and E(parallel) is numerically solved. A dispersion relation of the Alfvén wave in the fusion tokamak plasma is derived. The mode conversion and the energy deposition are qualitatively discussed on the basis of this relation. Both the analytical and numerical analyses indicate that (i) no matter whether m (poloidal mode number) is positive [N. Ding et al., Phys. Plasmas 2, 1529 (1995)] or negative (mainly studied in the present paper), the alphas do not affect the compressional Alfvén wave, but they do affect the KAW evidently; (ii) for m〈0, it is preferable to choose the frequency ω of the injected wave so that the inequality ω(approximately-greater-than)(Pm±1/Rm±1)−1ω*αm holds for optimal power absorption. The energy deposition at the resonant position close to the interior of the fusion tokamak plasma in taking account of the effects of ion sound and TTMP is less than that without taking account of these effects. But for the same β value, at the position adjacent to the edge the contrary is the case. For a certain resonant position, as the β value increases, the energy deposition decreases. © 1996 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

The effects of energetic ions on the electric field structure and the energy deposition of kinetic Alfvén wave (KAW) in a tokamak plasma are considered. A cylindrical geometry is adopted and a linearized kinetic model including the bulk plasma and the energetic ions is established. These effects of fusion alpha particles (abbreviated, alphas) in deuterium–tritium (D–T) tokamak plasmas are numerically analyzed. The energetic ions tend to alter the wave structure and the energy deposition. The absorption of the kinetic Alfvén wave by the bulk plasma depends sensitively on both the velocity distribution of alphas and the spatial profile of the alpha particle density, as well as on the frequency of the injected wave. Numerical results of the wave structure and the power absorption are given for the parameters of D–T plasmas. The present studies lead to the following discoveries: (1) The slowing-down alpha particle distribution reduces the KAWs energy deposition and the Maxwellian alphas have hardly any influence over it; (2) the more the (slowing-down) alphas near the resonant layer, the more heavily they prevent the KAWs power absorption by the bulk plasma; (3) the lower frequency of the injected wave within the range of KAWs continuum, the more heavily the KAWs structure and power absorption by the bulk plasma are affected by alpha particles; and (4) the energy deposition decreases rapidly as the total number of alphas increases. © 1995 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

In the well-known reversed shear discharges, it is observed that the ion thermal diffusivity (χi) falls below the standard neoclassical value (χineo), i.e., χi〈χineo. In this paper, local turbulent ion thermal pinch (χit〈0) is proposed as a candidate for interpreting the experimental results from χi=χineo+χit〈χineo. To test the idea, the two-fluid theory, developed by Weiland and the Chalmers group [J. Weiland et al., Nucl. Fusion 29, 1810 (1989); H. Nordman et al., ibid 30, 983 (1990)], is used in the reversed magnetic shear tokamak plasma to study the drift mode and associated ion heat transport. The theory is extended here to include both the radial electrical field shear (dEr/dr) and electron fluid velocity (Ve) in the sheared coordinate system. Remarkably different from B−1dEr/dr, k⋅Ve directly includes the safety factor q as well as the E×B velocity VE itself, where k is the magnetic configuration-dependent wave vector. As a result, the synergetic effects of B−1dEr/dr and k⋅Ve, especially those of k⋅Ve, lead to the local turbulent ion heat pinch in the negative and weak magnetic shear region because of the wave-particle resonance. The impact of B−1dEr/dr and k⋅Ve on the growth rate and ion heat pinch is numerically investigated. Qualitatively, the present results are in good agreement with the experimental trends. © 2001 American Institute of Physics.

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