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QSAR Studies on PCDD/Fs by Kernel PLS

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Chemical Research in Chinese Universities 2008年第5期24卷 541-545页

作者： TANG kai-lin LI tong-hua CHEN kai Department of Chemistry Tongji University Shanghai 200092 P. R. China

QSPR models of PCDD/Fs were generated by means of kernel partial least squares. The molecular distance-edge vector method was used as descriptors to get model I for predicting PCDD/Fs retention behavior. The chlorinated positions were also used and model II was obtained. In studied cases, the predictive ability of the KPLS model is comparable or superior to those of PLS and ANN. The results indicate that KPLS can be used as an alternative powerful modeling tool for QSPR studies.

关键词： QSPR modeling Kernel partial least squares PCDD/Fs

Analysis of severe core damage accident progression for the heavy water reactor

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Nuclear Science and Techniques 2010年第4期21卷 251-256页

作者： tong Lili YUAN kai YUAN Jingtian CAO Xuewu School of Mechanical Engineering Shanghai Jiao Tong University' Shanghai 200240 China

In this study,the severe accident progression analysis of generic Canadian deuterium uranium reactor 6 was preliminarily provided using an integrated severe accident analysis *** selected accident sequences were multiple steam generator tube rupture and large break loss-of-coolant accidents because these led to severe core damage with an assumed unavailability for several critical safety *** progressions of severe accident included a set of failed safety systems normally operated at full power,and initiative events led to primary heat transport system inventory blow-down or boil *** core heat-up and melting,steam generator response,fuel channel and calandria vessel failure were *** results showed that the progression of a severe core damage accident induced by steam generator tube rupture or large break loss-of-coolant accidents in a CANDU reactor was slow due to heat sinks in the calandria vessel and vault.

关键词：重水反应堆损坏事故蒸汽发生器堆芯 CANDU堆严重事故热传输系统事故分析

Mechanical Property, Oxidation and Ablation Resistance of C/C–ZrB_2–ZrC–SiC Composite Fabricated by Polymer Infiltration and Pyrolysis with Preform of C_f/ZrB_2

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Journal of Materials Science & Technology 2017年第5期33卷 481-486页

作者： Dong Huang Mingyu Zhang Qizhong Huang Liping Wang kai tong College of Materials Science and Engineering Hunan University State Key Laboratory for Powder Metallurgy Central South University

CJC-ZrB2-ZrC-SiC composites were fabricated by polymer infiltration and pyrolysis （PIP） with a preform of G/ZrB2. The carbon fibers and the resin carbon were coated with ceramic layer after PIP in the com- posites. The composite presents a pseudo-plastic fracture due to deflection of cracks and pullout of fibers. The composite has a higher bending strength by this method in comparison with the conventional PIP process due to fewer heat treatment cycles. The static oxidation test shows that the mass loss of the composites is no more than 1% after 20 rain oxidation at 1100 ~C. The ＂core-shell＂ structure between ZrC-SiC ceramic and other phases plays a positive role in preventing the inward diffusion of oxygen. The ablation resistance of the C/C-ZrB2-ZrC-SiC composite samples was tested using a plasma generator. After ablation for 120 s, the mass and linear ablation rates of the composites are 4.65 mg cm-2 s-1 and 2.46 μm s-1, respectively. The short carbon layer shows a better ablation resistance than the nonwoven carbon fabric layer after the ceramic coating is peeled off because of its higher ceramic content.

关键词： C/C composite Ceramic-matrix composites High temperature corrosion

Transport induced dimer state from topological corner states

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Science China(Physics,Mechanics & Astronomy) 2021年第5期64卷 91-96页

作者： kai-tong Wang Yafei Ren Fuming Xu Yadong Wei Jian Wang College of Physics and Energy Shenzhen UniversityShenzhen 518060China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Opioelectronic Engineering.Shenzhen UniversiryShenzhen 518060China Department of Physics The University of Texas at AustinAustinTexas 78712USA College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Deparment of Physics University of Hong KongHong KongChina

Recently, a new type of second-order topological insulator has been theoretically proposed by introducing an in-plane Zeeman field into the Kane-Mele model in the two-dimensional honeycomb lattice. A pair of topological corner states arise at the corners with obtuse angles of an isolated diamond-shaped flake. To probe the corner states, we study their transport properties by attaching two leads to the system. Dressed by incoming electrons, the dynamic corner state is very different from its static *** tunneling through the dressed corner state can occur by tuning the in-plane Zeeman field. At the resonance, the pair of spatially well separated and highly localized corner states can form a dimer state, whose wavefunction extends almost the entire bulk of the diamond-shaped flake. By varying the Zeeman field strength, multiple resonant tunneling events are mediated by the same dimer state. This re-entrance effect can be understood by a simple model. These findings extend our understanding of dynamic aspects of the second-order topological corner states.

关键词： higher-order topological insulators multiple resonant tunneling in-plane Zeeman field two-dimensional honeycomb lattice

Adaptive semi-empirical model for non-contact atomic force microscopy

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Chinese Physics B 2022年第8期31卷 682-687页

作者： Xi Chen Jun-kai tong Zhi-Xin Hu Center for Joint Quantum Studies and Department of Physics Institute of ScienceTianjin UniversityTianjin 300350China State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China

Non-contact atomic force microscope is a powerful tool to investigate the surface topography with atomic *** we propose a new approach to estimate the interaction between its tips and samples,which combines a semi-empirical model with density functional theory(DFT)*** generated frequency shift images are consistent with the experiment for mapping organic molecules using CuCO,Cu,CuCl,and CuO_(x)*** approach achieves accuracy close to DFT calculation with much lower computational cost.

关键词： semi-empirical model atomic force microscopy density functional theory functionalized tips

Evolution of individual quantum Hall edge states in the presence of disorder

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Frontiers of physics 2018年第4期13卷 129-137页

作者： kai-tong Wang Fuming Xu Yanxia Xing Hong-Kang Zhao 1School of Physics Beijing Institute of Technology Beijing 100081 China Shenzhen Key Laboratory of Advanced Thin Films and Applications College of Physics and Energy Shenzhen University Shenzhen 518060 China Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing 100081 China

By using the Bloch eigenmode matching approach, we numerically study the evolution of individual quantum Hall edge states with respect to disorder. As demonstrated by the two-parameter renormal- ization group flow of the Hall and Thouless conductances, quantum Hall edge states with high Chern number n are completely different from that of the n = 1 case. Two categories of individual edge modes are evaluated in a quantum Hall system with high Chern number. Edge states from the lowest Landau level have similar eigenfunctions that are well localized at the system edge and independent of the Fermi energy. On the other hand, at fixed Fermi energy, the edge state from higher Landau levels exhibit larger expansion, which results in less stable quantum Hall states at high Fermi energies. By presenting the local current density distribution, the effect of disorder on eigenmode-resolved edge states is distinctly demonstrated.

关键词： quantum Hall edge states Landau level quantum phase transition

Transport features of topological corner states in honeycomb lattice with multihollow structure

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Frontiers of physics 2022年第4期17卷 83-89页

作者： kai-tong Wang Fuming Xu Bin Wang Yunjin Yu Yadong Wei School of Physics and Engineering Henan University of Science and TechnologyLuoyang 471023China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

Higher-order topological phase in 2-dimensional(2D)systems is characterized by in-gap corner states,which are hard to detect and *** numerically investigate transport properties of topological corner states in 2D honeycomb lattice,where the second-order topological phase is induced by an in-plane Zeeman field in the conventional Kane–Mele *** engineering multihollow structures with appropriate boundaries in honeycomb lattice,multiple corner states emerge,which greatly increases the probability to observe them.A typical two-probe setup is built to study the transport features of a diamond-shaped system with multihollow *** results reveal the existence of global resonant states in bulk insulator,which corresponds to the resonant tunneling of multiple corner states and occupies the entire scattering ***,based on the well separated energy levels of multiple corner states,a single-electron source is constructed.

关键词： second-order topological insulator Kane–Mele model global resonant state single-electron source

Capability of TMPA products to simulate streamflow in upper Yellow and Yangtze River basins on Tibetan Plateau

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Water Science and Engineering 2014年第3期7卷 237-249页

作者： Zhen-chun HAO kai tong Xiao-li LIU Lei-lei ZHANG State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of Sciences

Due to the high elevation, complex terrain, severe weather, and inaccessibility, direct meteorological observations do not exist over large portions of the Tibetan Plateau, especially the western part of it. Satellite rainfall estimates have been very important sources for precipitation information, particularly in rain gauge-sparse regions. In this study, Tropical Rainfall Measuring Mission （TRMM） Multi-satellite Precipitation Analysis （TMPA） products 3B42, RTV5V6, and RTV7 were evaluated for their applicability to the upper Yellow and Yangtze River basins on the Tibetan Plateau. Moreover, the capability of the TMPA products to simulate streamflow was also investigated using the Variable Infiltration Capacity （VIC） semi-distributed hydrological model. Results show that 3B42 performs better than RTVSV6 and RTV7, based on verification of the China Meteorological Administration （CMA） observational precipitation data. RTVSV6 can roughly capture the spatial precipitation pattern but overestimation exists throughout the entire study region. The anticipated improvements of RTV7 relative to RTVSV6 have not been realized in this study. Our results suggest that RTV7 significantly overestimates the precipitation over the two river basins, though it can capture the seasonal cycle features of precipitation. 3B42 shows the best performance in streamflow simulation of the abovementioned satellite products. Although involved in gauge adjustment at a monthly scale, 3B42 is capable of daily streamflow simulation. RTV5V6 and RTV7 have no capability to simulate streamflow in the upper Yellow and Yangtze River basins.

关键词： TMPA CMA precipitation data VIC hydrological model streamflow simulation upper Yellow and Yangtze River basins

PREPARATION OF POLYIMIDE-BaTiO3 HYBRID FILMS BY A DISPERSION PROCESS AND THEIR MICROSTRUCTURE

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Chinese Journal of Polymer Science 2001年第1期19卷 13-17页

作者： Yue-sheng Li Yue-jin tong kai Jing Meng-xian Ding State Key Laboratory of Polymer Physics and Chemistry PCLCC*** Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China State Key Laboratory of Polymer Physics and Chemistry PCLCC*** Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China State Key Laboratory of Polymer Physics and Chemistry PCLCC*** Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China State Key Laboratory of Polymer Physics and Chemistry PCLCC*** Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China

Barium titanate (BaTiO3) powders with particle sizes of 30 similar to 50 nm were prepared from barium stearate, titanium alkoxides and stearic acid by stearic acid-gel method. Dispersing the agglomerate of BaTiO3 nanoparticles into poly(amic acid) solution followed by curing led to the formation of polyimide hybrid films. The hybrid films were transparent and well distributed with BaTiO3 nanoparticles when the BaTiO3 content was less than 1 wt%. Highly loaded hybrid film containing 30 wit % BaTiO3 was tough, had a smooth surface and possessed much higher dielectric and piezoelectric constants than the parent polyimide.

关键词： polyimide barium titanate nanocomposite hybrid film