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Search Results: 1 - 10 of 45478 matches for " Ya-Jing Peng "
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Quantum interference effect in electron tunneling through a quantum-dot-ring spin valve
Ma Jing-Min,Zhao Jia,Zhang Kai-Cheng,Peng Ya-Jing
Nanoscale Research Letters , 2011,
Abstract: Spin-dependent transport through a quantum-dot (QD) ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR) as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively. PACS numbers:
Influence of microwave treatment on grinding and dissociation characteristics of vanadium titano-magnetite
Jun-peng Wang,Tao Jiang,Ya-jing Liu,Xiang-xin Xue
- , 2019, DOI: https://doi.org/10.1007/s12613-019-1720-1
Abstract: The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite (VTM) ore were investigated using scanning electron microscopy (SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves’ selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics.
Ultrafast multiplex CARS investigation of vibrational characteristics in chloroform and PMMA

Wang Ying-Hui,Peng Ya-Jing,He Xing,Song Yun-Fei,Yang Yan-Qiang,

中国物理 B , 2009,
Abstract: This paper demonstrates the femtosecond time-resolved coherent anti-Stokes Raman scattering by using folded BOXCARS geometry where an ultrashort broadband coherent white light continuum was used as Stokes pulse, and carries out the non-contact detection at long distance. The CARS signal is so easy to be detected that it can be seen even by nude eye. The C--H bonds of chloroform or PMMA were detected and the vibration modes belonging to the side chain and the main chain in PMMA were also compared. Their vibrational characteristics involved decay process and quantum beating were discussed. This modified CARS experimental technique could make up the deficiency of traditional CARS technique.
Theoretical investigation on near-infrared and visible absorption spectra of nanometallic aluminium with oxide coating in nanoenergetic materials: size and shape effects

Peng Ya-Jing,Zhang Shu-Ping,Wang Ying-Hui,Yang Yan-Qiang,

中国物理 B , 2008,
Abstract: The effects of metal core dimension, oxide shell thickness and ellipsoid aspect ratio of Al--Alcore-shell nanoparticle, optical absorption, interband transition, nanoenergetic materialProject supported by the National Natural Science Foundation of China (Grant No 20573028).7865, 7830E, 7820DThe effects of metal core dimension, oxide shell thickness and ellipsoid aspect ratio of Al--Alcore-shell nanoparticle, optical absorption, interband transition, nanoenergetic materialProject supported by the National Natural Science Foundation of China (Grant No 20573028).7865, 7830E, 7820DThe effects of metal core dimension, oxide shell thickness and ellipsoid aspect ratio of Al--Alcore-shell nanoparticle, optical absorption, interband transition, nanoenergetic materialProject supported by the National Natural Science Foundation of China (Grant No 20573028).7865, 7830E, 7820DThe effects of metal core dimension, oxide shell thickness and ellipsoid aspect ratio of Al--Al$_{2}$O$_{3}$ core-shell nanoparticles on the near-infrared and visible absorption spectra of nanocomposite Al--Al$_{2}$O$_{3}$/nitrocellulose(NC) film are investigated by numerical calculations. Both the size-dependent interband transitions and frequency-dependent free electron damping of the nanometallic aluminium are taken into account in the calculations. Oxidation effect of nanoaluminium is also analysed. It is shown that oxidation may enhance but may also reduce the optical absorption, depending on the excited light energy and initial dimension of nanoparticle. Metal core size and excited light energy dominate the absorption characteristic. The absorption ability of ellipsoidal nanoparticles is larger than that of spheroidal nanoparticles and increases by the square index as the aspect ratio increases. These calculations will provide some significant theoretical guidance for the preparation and laser ignition of nanoenergetic materials.
Activated Scavenger Receptor A Promotes Glial Internalization of Aβ
He Zhang, Ya-jing Su, Wei-wei Zhou, Shao-wei Wang, Peng-xin Xu, Xiao-lin Yu, Rui-tian Liu
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0094197
Abstract: Beta-amyloid (Aβ) aggregates have a pivotal role in pathological processing of Alzheimer’s disease (AD). The clearance of Aβ monomer or aggregates is a causal strategy for AD treatment. Microglia and astrocytes are the main macrophages that exert critical neuroprotective roles in the brain. They may effectively clear the toxic accumulation of Aβ at the initial stage of AD, however, their functions are attenuated because of glial overactivation. In this study, we first showed that heptapeptide XD4 activates the class A scavenger receptor (SR-A) on the glia by increasing the binding of Aβ to SR-A, thereby promoting glial phagocytosis of Aβ oligomer in microglia and astrocytes and triggering intracellular mitogen-activated protein kinase (MAPK) signaling cascades. Moreover, XD4 enhances the internalization of Aβ monomers to microglia and astrocytes through macropinocytosis or SR-A-mediated phagocytosis. Furthermore, XD4 significantly inhibits Aβ oligomer-induced cytotoxicity to glial cells and decreases the production of proinflammatory cytokines, such as TNF-α and IL-1β, in vitro and in vivo. Our findings may provide a novel strategy for AD treatment by activating SR-A.
Phase Behavior of Sphere-Forming Triblock Copolymers in Films  [PDF]
Hong-Ge Tan, Qing-Gong Song, Xin-Huan Yang, Ya-Jing Deng
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.23023
Abstract: The self-assembly of sphere-forming triblock copolymers confined between two thin homogeneous surfaces is investigated based on mean-field dynamic density functional theory. The morphologies deviating from the bulk sphere-forming phase are revealed, including cylinders oriented perpendicular to the surface, cylinders oriented parallel to the surface, perforated lamellae and lamellae by varying film thickness and surface field strength. The phase diagram of surface reconstruction is also constructed. By comparing the present phase diagram with the other relevant phase diagram for the cylinder-forming triblock copolymer film, the difference between the sphere-forming and the cylinder-forming triblock copolymer thin film is discussed.
Partial equilibrium approximations in Apoptosis
Ya-Jing Huang,Wen-An Yong
Quantitative Biology , 2012,
Abstract: Apoptosis is one of the most basic biological processes. In apoptosis, tens of species are involved in many biochemical reactions with times scales of widely differing orders of magnitude. By the law of mass action, the process is mathematically described with a large and stiff system of ODEs (ordinary differential equations). The goal of this work is to simplify such systems of ODEs with the PEA (partial equilibrium approximation) method. In doing so, we propose a general framework of the PEA method together with some conditions, under which the PEA method can be justified rigorously. The main condition is the principle of detailed balance for fast reactions as a whole. With the justified method as a tool, we made many attempts via numerical tests to simplify the Fas-signaling pathway model due to Hua et al. (2005) and found that nine of reactions therein can be well regarded as relatively fast. This paper reports our simplification of Hua at el.'s model with the PEA method based on the fastness of the nine reactions, together with numerical results which confirm the reliability of our simplified model.
Myosin Light-Chain Kinase Is Necessary for Membrane Homeostasis in Cochlear Inner Hair Cells
Guang-Jie Zhu, Fang Wang, Chen Chen, Lin Xu, Wen-Cheng Zhang, Chi Fan, Ya-Jing Peng, Jie Chen, Wei-Qi He, Shi-Ying Guo, Jian Zuo, Xia Gao, Min-Sheng Zhu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034894
Abstract: The structural homeostasis of the cochlear hair cell membrane is critical for all aspects of sensory transduction, but the regulation of its maintenance is not well understood. In this report, we analyzed the cochlear hair cells of mice with specific deletion of myosin light chain kinase (MLCK) in inner hair cells. MLCK-deficient mice showed impaired hearing, with a 5- to 14-dB rise in the auditory brainstem response (ABR) thresholds to clicks and tones of different frequencies and a significant decrease in the amplitude of the ABR waves. The mutant inner hair cells produced several ball-like structures around the hair bundles in vivo, indicating impaired membrane stability. Inner hair cells isolated from the knockout mice consistently displayed less resistance to hypoosmotic solution and less membrane F-actin. Myosin light-chain phosphorylation was also reduced in the mutated inner hair cells. Our results suggest that MLCK is necessary for maintaining the membrane stability of inner hair cells.
Period doubling motion in vertically vibrated granular beds

Jiang Ze-Hui,Liu Xin-Ying,Peng Ya-Jing,Li Jian-Wei,

物理学报 , 2005,
Abstract: Experiments are performed to investigate the impact interaction between granular bed and container bottom, where the container is vertically vibrated. It is observed that the impact strength, controlled by the normalized vibration acceleration, undergoes a series of period doubling bifurcations, typically in the sequence of period-doubling, period-quadrupling, chaos, period-tripling, period-sextupling, chaos, period-quadrupling, period-octupling, and chaos. A condensed state of particles at the bottom of the container is observed, in which the particles are densely compacted and move as a bulk block in the vertical direction. Based on a completely inelastic bouncing ball model, a possible explanation for the bifurcation phenomena is presented.
Thermal dynamic analysis of picosecond and nanosecond single pulse laser flash-heating of Al/NC nanoenergetic composites

Peng Ya-Jing,Liu Yu-Qiang,Wang Ying-Hui,Zhang Shu-Ping,Yang Yan-Qiang,

物理学报 , 2009,
Abstract: Thermal dynamic process of single pulse laser-induced reaction is theoretically analyzed for a novel system of composite energetic materials containing nanometallic particles. The instantaneous power density of laser energy absorbed by nanometallic particles dispersed in a matrix is exactly deduced. The process of absorbing pulse laser energy for nanometallic aluminum particles embedded in nitrocellulose (Al/NC) thin film and the heat propagation process of hot spot accompanying exothermic chemical reaction are simulated numerically based on thermal decomposition mechanism. The reaction diameters are calculated for different concentrations of Al/NC thin films flashed by 100ps, 10ns and 25ns single pulse laser with the reaction threshold intensities having been obtained from experiment, respectively. Calculation results are compared with the experiment data, which shows that the thermal decomposition mechanism generally corresponds to the reaction processes of 10ns and 25ns pulse laser but does not correspond to that of the 100ps pulse laser.
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