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Collective Excitation and Quantum Depletion of a Bose-Einstein Condensate in a Periodic Array of Quantum Wells

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Chinese Physics Letters 2014年第3期31卷 10-13页

作者： XUE Rui li wei-dong liANG Zhao-Xin Key Laboratory of Instrumentation Science and Dynamic Measurement North University of China Taiyuan 030051 National Key Laboratory for Electronic Measurement Technology North University of China Taiyuan 030051 Department of Physics North University of China Taiyuan 030051 Engineering Technology Research Center of Shanxi Province for Opto-Electronic Information and Instrument North University of China Taiyuan 030051 Institute of Theoretical Physics and Department of Physics Shanxi University Taiyuan 030006 Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016

With the help of a set of exact closed-form solutions to the stationary Gross–Pitaevskii （GP） equation, we calculate the collective excitation and quantum depletion of a weakly interacting Bose gas in the presence of a periodic array of quantum wells. The excitation spectrum （Bogoliubov spectrum） is obtained from the solution of the linearized time-dependent GP equation, which develops energy bands hωj（ p） periodic in quasi-momentum space. Moreover, we calculate the excitation strengths Zj（ p） relative to the density operator and then the dynamic structure factor S（ p,ω）. Accordingly, the analytical expressions of quantum depletion of the system are obtained. We find that the quantum depletion is enhanced when the interatomic interactions become larger and the potential is sufficiently deep. The conditions for the possible experimental realization of our scenario are also proposed.

关键词： Semiconductor quantum wells

Synthesis of 6E-Geranylgeraniol-19-oic Acid

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Chemical Research in Chinese Universities 2003年第3期19卷 294-296页

作者： li Shu hua PENG li Zeng li wei dong li Yu lin National Laboratory of Applied Organic Chemistry and Institute of Organic Chemistry Lanzhou UniversityLanzhou 730000P.R.China

The present paper deals with the facile synthesis of 6 E geranylgeraniol 19 oic acid(1), a naturally occuring alicyclic diterpene acid, by a Horner Wadsworth Emmons olefination of two readily available fragments 7 and 3.

关键词： Horner Wadsworth Emmons reaction 6E-Geranylgeraniol-19-oic acid Synthesis

Analysis of Electronic Structures for SmCo5 Compound

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Journal of Rare Earths 2004年第Z1期22卷 103-106页

作者： Zhang Changwen li Hua Guo Yongquan li wei dong Jianmin School of physics and Microelectronics Shandong University Jinan 250100 China School of physics and Microelectronics Shandong University Jinan 250100 China Institute of Functional Materials Central Iron &Steel Research Institute Beijing 100081 China Institute of Functional Materials Central Iron &Steel Research Institute Beijing 100081 China School of physics and Microelectronics Shandong University Jinan 250100 China

The spin-polarized MS-Xα method is employed to study the electronic structure and the magnetic property of the SmCo5 *** to the calculated results, the magnetic moment per Sm is 1.29μB in the SmCo5 compound, which agrees with that of *** analyzed result reveals that some negative exchange couplings occurring at six energy levels induce the distinct decrease of Curie temperature and the magnetic moment per *** valence electron numbers of 2.48, which are derived from the orbital hybridization from s, p, d and f functions between Sm and Co atoms, are transferred to Sm(5d0) ***, the exchange interactions between 3d ～ 5d electrons lead to the magnetic coupling between Sm and Co, which results in the long-range ferromagnetic-order inside the SmCo5 compound.

关键词： electronic structure atomic magnetic moment exchange coupling Curie temperature

Fermi-Decay Law of Bose-Einstein Condensate Trapped in an Anharmonic Potential

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Chinese Physics Letters 2012年第4期29卷 19-22页

作者： liU Yuan JIA Ya-Fei li wei-dong Institute of Theoretical Physics and Department of Physics Shanxi UniversityTaiyuan 030006

The Fermi-decay law of Bose Einstein condensate,which is trapped by a cigar-shaped anharmonic trap and subjected to a weak random perturbation,is investigated by numerically calculating quantum fidelity (Loschmidt echo),to reveal the coherence loss of the *** find that there are three indispensable factors,anharmonic trap,weak random perturbation and nonlinear interaction,in charging of the Fermi-decay *** anharmonic trap creates anharmonic oscillations,and the weak random perturbation causes coherence loss by disturbing their coherent oscillations,while the nonlinear interaction enhances the loss to the Fermi-decay *** on the Fermi-decay law,some suggestions are presented to prolong the coherent time during coherently manipulating condensates.

关键词： harmonic Fermi coherent

Time Dependence of Entropy Flux and Entropy Production of a Dissipative Dynamical System Driven by Non-Gaussian Noise

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Communications in Theoretical Physics 2008年第6期49卷 1561-1566页

作者： GUO Yong-Feng XU wei li dong-Xi XIE Wen-Xian Department of Applied Mathematics Northwestern Polytechnical University Xi＇an 710072 China

A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition of Shannon＇s information entropy, the exact time dependence of entropy flux and entropy production of the system is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculation can be used to interpret the interplay of the dissipative constant and non-Gaussian noise on the entropy flux and entropy production.

关键词： information entropy entropy flux and entropy production non-Gaussian noise Fokker-Planck equation

Optimizations for High Performance Network Virtualization

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Journal of Computer Science & Technology 2016年第1期31卷 107-116页

作者： Fan-Fu Zhou Ru-Hui Ma Jian li li-Xia Chen wei-dong Qiu Hai-Bing Guan Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai 200240 China

The increasing requirements of intensive interoperaterbility among the distributed nodes desiderate the high performance network connections, owing to the substantial growth of cloud computing and datacenters. Network I/O virtualization aggregates the network resource and separates it into manageable parts for particular servers or devices, which provides effective consolidation and elastic management with high agility, flexibility and scalability as well as reduced cost and cabling. However, both network I/O virtualization aggregation and the increasing network speed incur higher traffic density, which generates a heavy system stress for I/O data moving and I/O event processing. Consequently, many researchers have dedicated to enhancing the system performance and alleviating the system overhead for high performance networking virtualizatiou. This paper first elaborates the mainstreaming I/O virtualization methodologies, including device emulation, split-driver model and hardware assisted model. Then, the paper discusses and compares their specific advantages in addition to performance bottlenecks in practical utilities. This paper mainly focuses on the comprehensive survey of state- of-the-art approaches for performance optimizations and improvements as well as the portability management for network I/O virtualization. The approaches include various novel data delivery schemes, overhead mitigations for interrupt processing and adequate resource allocations for dynamic network states. Finally, we highlight the diversity of I/O virtualization besides the performance improvements in network virtualization infrastructure.

关键词： network virtualization single root I/O virtualization (SR-IOV) virtual machine monitor (VMM)

Thermodynamic study on the interaction between anti-tumor drug tegafur and human serum albumin

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Chinese Chemical Letters 2007年第7期18卷 891-894页

作者： lin wei li dong dong Wang De Zhi Sun Min liu You Ying Di Hua Chao Yan College of Chemistry and Chemical Engineering Liaocheng University Liaocheng 252059 China

The changes of thermodynamic properties of the system on interaction between tegafur and human serum albumin （HSA） and the changes of secondary structure units of HSA in the system at 298.15 K have been investigated by the Nano-Watt-Scale isothermal titration calorimetry （ITC）, the Langmuirs binding model and the circular dichroism （CD） spectrometry.

关键词： Tegafur Human serum albumin Isothermal titration calorimetry Circular dichroism

Source Apportionment of Heavy Metals in Soils Using Multivariate Statistics and Geostatistics

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Pedosphere 2013年第4期23卷 437-444页

作者： QU Ming-Kai li wei-dong ZHANG Chuan-Rong WANG Shan-Qin YANG Yong HE li-Yuan Department of Resource and Environmental Information College of Resources and Environment Huazhong Agricultural University Department of Geography and Center for Environmental Sciences and Engineering University of Connecticut

The main objectives of this study were to introduce an integrated method for effectively identifying soil heavy metal pollution sources and apportioning their contributions, and apply it to a case study. The method combines the principal component analysis/absolute principal component scores (PCA/APCS) receptor model and geostatistics. The case study was conducted in an area of 31 km2 in the urban-rural transition zone of Wuhan, a metropolis of central China. 124 topsoil samples were collected for measuring the concentrations of eight heavy metal elements (Mn, Cu, Zn, Pb, Cd, Cr, Ni and Co). PCA results revealed that three major factors were responsible for soil heavy metal pollution, which were initially identified as "steel production", "agronomic input" and "coal consumption". The APCS technique, combined with multiple linear regression analysis, was then applied for source apportionment. Steel production appeared to be the main source for Ni, Co, Cd, Zn and Mn, agronomic input for Cu, and coal consumption for Pb and Cr. Geostatistical interpolation using ordinary kriging was finally used to map the spatial distributions of the contributions of pollution sources and further confirm the result interpretations. The introduced method appears to be an effective tool in soil pollution source apportionment and identification, and might provide valuable reference information for pollution control and environmental management.

关键词： pollution source receptor model source identification steel production

Histological and Ultrastructural Observation Reveals Significant Cellular Differences between Agrobacterium Transformed Embryogenic and Non-embryogenic Calli of Cotton

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Journal of Integrative Plant Biology 2009年第5期51卷 456-465页

作者： Hai-Hong Shang Chuan-liang liu Chao-Jun Zhang Feng-lian li wei-dong Hong Fu-Guang li Key Laboratory of Cotton Genetic Improvement Ministry of Agriculture Chinese Cotton Research Institute Chinese Agricultural Academy of Sciences Anyang 455004 China

Over the past few decades genetic engineering has been applied to improve cotton breeding. Agrobacterium medicated transformation is nowadays widely used as an efficient approach to introduce exogenous genes into cotton for genetically modified organisms. However, it still needs to be improved for better transformation efficiency and higher embryogenic callus induction ratios. To research further the difference of mechanisms for morphogenesis between embryogenic callus and non-embryogenic callus, we carried out a systematical study on the histological and cellular ultrastructure of Agrobacterium transformed calli. Results showed that the embryogenic callus developed nodule-like structures, which were formed by small, tightly packed, hemispherical cells. The surface of some embryogenic callus was covered with a fibrilar-like structure named extracellular matrix. The cells of embryogenic calli had similar morphological characteristics. Organelles of embryogenic callus cells were located near the nucleus, and chloroplasts degraded to proplastid-like structures with some starch grains. In contrast, the non-embryogenic calli were covered by oval or sphere cells or small clusters of cells. It was observed that cells had vacuolation of cytoplasm and plastids with a well organized endomembrane system. This study aims to understand the mechanisms of embryogenic callus morphogenesis and to improve the efficiency of cotton transformation in future.

关键词： cell organization pattern chloroplasts embryogenic callus Gossypiurn hirsutum histological structure transformation ultrastructure