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Studies on Electrochemical Property of LiFePO_4/C as Cathode material for Lithium Ion Batteries

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Chemical Research in Chinese Universities 2006年第1期22卷 73-75页

作者： HUANG xiao-wen SHI Peng-fei Faculty of Applied Chemistry Harbin Institute of Technology Harbin 150001 P.R. China College of material Science and Engineering Shandong University of Science and Technology Qingdao 266510 P. R. China

LiFePO4/C samples were prepared at different temperatures by adding sngar to the synthetic precursor. The samples were characterized by X-ray diffraction（XRD）. Their crystal phases show an olivine structure. Only the sample obtained at 700℃ has a larger discharge capacity, which has good electrochemical properties： its discharge specific capacity is 120. 3 mah/g at a current of 0. 05 ma, and its capacity fade is very low after 20 cycles. It is demonstrated that the best synthetic temperature should be 700℃.

关键词： Olivine Lithium ion battery Carbon-coated LiFePO4

S-wave resonance contributions to B(s)^0→ηc(2S)π^+π^-in the perturbative QCD factorization approach

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Chinese Physics C 2017年第8期41卷 47-52页

作者： Ai-Jun ma Ya Li Wen-fei Wang Zhen-Jun xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Institute of Theoretical Physics Shanxi UniversityTaiyuanShanxi 030006China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China

By employing the perturbative QCD（PQCD） factorization approach, we study the quasi-two-body B（s）^0→ηc（2S）π^＋π^- decays, where the pion pair comes from the S-wave resonance f0（X）. The Breit-Wigner formula for the f0（500） and f0（1500） resonances and the Flatt′e model for the f0（980） resonance are adopted to parameterize the time-like scalar form factors in the two-pion distribution amplitudes. As a comparison, Bugg＇s model is also used for the wide f0（500） in this work. For decay rates, we found the following PQCD predictions：（a）-B（Bs^0 →ηc（2S）f0（X）[π^＋π^-]s）= 2.67-1.08^＋1.78 ×10^-5 when the contributions from f0（980） and f0（1500） are all taken into account;（b）B（B0→η-c（2S）f0（500）[π^＋π^-]s） = 1.40（-0.56）（＋0.92） ×10^-6 in the Breit-Wigner model and 1.53（-0.61）^（＋0.97） ×10^-6 in Bugg＇s model.

关键词： PQCD factorization approach two-pion distribution amplitudes quasi-two-body decay

Extant primates and development of primatology in China: Publications, student training, and funding

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Zoological Research 2018年第4期39卷 249-254页

作者： Peng-fei Fan Chi ma School of Life Sciences Sun Yat-Sen University

China supports the richest non-human primate diversity in the northern hemisphere, providing an excellent opportunity for Chinese primatologists to take a leading role in advancing the study of primatology Primatology in China began to flourish after 1979. To date, Chinese primatologists have published more than 1 000 papers in journals indexed by the Chinese Science Citation Database and the Web of Science Core Collection, and universities and academic institutions have trained 107 PhD students and 370 masters students between 1984 and 2016. In total, the National Science Foundation of China has funded 129 primate projects （RMB 71.7 million） supporting 59 researchers from 28 organizations. However, previous research has also shown obvious species bias. Rhinopithecus roxellana, Rhinopithecus bieti, and macaca mulatta have received much greater research attention than other species. Researchers have also tended to continue to study the same species （55.2%） they studied during their PhD training. To promote the development of primatology in China, we suggest （1） the need for a comprehensive primatology textbook written in Chinese, （2） continued training of more PhD students, and （3） encouragement to study less well-known primate species.

关键词： Gibbon Snub-nosed monkey Leafmonkey macaque Slow Iories

Brake Orbits of First Order Convex Hamiltonian Systems with Particular Anisotropic Growth

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Acta mathematica Sinica,English Series 2020年第2期36卷 171-178页

作者： xiao fei ZHANG Chun Gen LIU School of mathematics and Statistics Shanxi Datong UniversityDatong 037009P.R.China School of mathematics and Information Science Guangzhou UniversityGuangzhou 510006P.R.China

Combining the dual least action principle with Mountain-pass lemma,we obtain the existence of brake orbits for first-order convex Hamiltonian systems with particular anisotropic growth.

关键词： Hamiltonian system brake orbit anisotropic grow th Mountain-pass lemma

Ince-Strutt Stability Charts for Ship Parametric Roll Resonance in Irregular Waves

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China Ocean Engineering 2017年第4期31卷 447-457页

作者： ZHANG xiao YANG He-zhen xiao fei XU Pei-ji National Key Laboratory on Ship Vibration &Noise China Ship Development and Design Center State Key Laboratory of Ocean Engineering School of Naval Architecture.Ocean and Civil EngineeringShanghai Jiao Tong University School of Civil and Environmental Engineering Nanyang Technological University

Ince-Strutt stability chart of ship parametric roll resonance in irregular waves is conducted and utilized for the exploration of the parametric roll resonance in irregular waves. Ship parametric roll resonance will lead to large amplitude roll motion and even wreck. Firstly, the equation describing the parametric roll resonance in irregular waves is derived according to Grim’s effective theory and the corresponding Ince-Strutt stability charts are obtained. Secondly, the differences of stability charts for the parametric roll resonance in irregular and regular waves are compared. Thirdly, wave phases and peak periods are taken into consideration to obtain a more realistic sea condition. The influence of random wave phases should be taken into consideration when the analyzed points are located near the instability boundary. Stability charts for different wave peak periods are various. Stability charts are helpful for the parameter determination in design stage to better adapt to sailing condition. Last, ship variables are analyzed according to stability charts by a statistical approach. The increase of the metacentric height will help improve ship stability.

关键词： parametric instability parametric rolling multi-frequency irregular waves Ince-Strutt stability chart

Asymptotic inference for AR(1) panel data

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Applied mathematics(A Journal of Chinese Universities) 2020年第3期35卷 265-280页

作者： SHEN Jian-fei PANG Tian-xiao School of mathematical Sciences Zhejiang UniversityHangzhou 310027China

A general asymptotic theory is given for the panel data AR(1) model with time series independent in different cross sections. The theory covers the cases of stationary process, local to unity process, unit root process, mildly integrated, mildly explosive and explosive processes. It is assumed that the cross-sectional dimension and time-series dimension are respectively N and T. The results in this paper illustrate that whichever the process is, with an appropriate regularization, the least squares estimator of the autoregressive coefficient converges in distribution to a normal distribution with rate at least O(N-1/3). Since the variance is the key to characterize the normal distribution, it is important to discuss the variance of the least squares estimator. We will show that when the autoregressive coefficient ρ satisfies |ρ| 1. ρ = 1 is the critical point where the convergence rate changes radically. The transition process is studied by assuming ρ depending on T and going to 1. An interesting phenomenon discovered in this paper is that, in the explosive case, the least squares estimator of the autoregressive coefficient has a standard normal limiting distribution in the panel data case while it may not has a limiting distribution in the univariate time series case.

关键词： AR(1)model Least squares estimator Limiting distribution Non-stationray Panel data

Information and knowledge behind data from underground rock grouting

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1326-1339页

作者： fei xiao Qian Liu Zhiye Zhao Department of Civil Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016China School of Civil and Environmental Engineering Nanyang Technological University50 Nanyang Avenue639798Singapore

Data related to the pre-grouting work of a large underground project are systematically analyzed to reveal the mechanism behind,to shed some light on the execution of practical grouting,and to enrich the theory of engineering *** is generally taken as an effective way for controlling nonignorable water seepage during underground rock *** various models have been developed to guide grouting design or to specify criteria for grouting stop,it does not change the fact that grouting is still highly ***,explanation of the current situation due to grouting complexity is given through step-by-step data analysis,where the impact on grouting parameters from the geological and hydrogeological conditions is investigated,and the grouting features of two tunnels located at the same depth below the sea surface are compared and ***,the data from individual grout hole are used to construct the regional geological conditions via inverse *** is found that grouting of fractured rock masses is accompanied with great uncertainty,and field grouting data can contribute significantly to a better understanding of the regional geological conditions around an underground tunnel or rock cavern.

关键词： Field grouting data Water seepage Rock grouting Inverse modelling Data analytics Geological conditions

Dynamics of bright soliton in a spin–orbit coupled spin-1 Bose–Einstein condensate

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Chinese Physics B 2021年第6期30卷 164-168页

作者： Hui Guo Xu Qiu Yan ma Hai-Feng Jiang xiao-fei Zhang Key Laboratory of Time and Frequency Primary Standards National Time Service CenterChinese Academy of Sciences(CAS)Xi'an 710600China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Economics and management Chongqing Normal UniversityChongqing 401331China CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics University of Science and Technology of ChinaShanghai 201315China

We have investigated the dynamics of bright solitons in a spin–orbit coupled spin-1 Bose–Einstein condensate analytically and numerically. By using the hyperbolic sine function as the trial function to describe a plane wave bright soliton with a single finite momentum, we have derived the motion equations of soliton's spin and center of mass, and obtained its exact analytical solutions. Our results show that the spin–orbit coupling couples the soliton's spin with its center-of-mass motion, the spin oscillations induced by the exchange of atoms between components result in the periodical oscillation of center-of-mass, and the motion of center of mass of soliton can be viewed as a superposition of periodical and linear motions. Our analytical results have also been confirmed by the direct numerical simulations of Gross–Pitaevskii equations.

关键词： Bose–Einstein condensate spin–orbit coupling soliton

Growth traits and nitrogen assimilation-associated physiological parameters of wheat(Triticum aestivum L.) under low and high N conditions

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Journal of Integrative Agriculture 2015年第7期14卷 1295-1308页

作者： ZHANG fei-fei GAO Si ZHAO Yuan-yuan ZHAO xiao-lei LIU xiao-man xiao Kai College of Agronomy Agricultural University of Hebei

In this study, 14 wheat cultivars with contrasting yield and N use efficiency （NUE） were used to investigate the agronomic and NUE-related traits, and the N assimilation-associated enzyme activities under low and high N conditions. Under deficient-N, the cultivars with high N uptake efficiency （UpE） and high N utilization efficiency （UtE） exhibited higher plant biomass, yields, and N contents than those with medium and low NUEs. The high UpE cultivars accumulated more N than other NUE type cultivars. Under sufficient-N, the tested cultivars showed similar patterns in biomass, yield, and N content to those under deficient-N, but the varietal variations in above traits were smaller. In addition, the high UpE cultivars displayed much more of root biomass and larger of root length, surface area, and volume than other NUE type cultivars, indicating that the root morphological traits under N deprivation are closely associated with the plant biomass through its improvement of the N acquisition. The high UtE cultivars showed higher activities of nitrate reductase （NR）, nitrite reductase （NIR）, and gluta- mine synthetase （GS） at stages of seediling, heading and filling than other NUE type cultivars under both low and high N conditions. Moreover, the high UpE and UtE cultivars also displayed higher photosynthetic rate under deficient-N than the medium and low NUE cultivars. Together, our results indicated that the tested wheat cultivars possess dramatically genetic variations in biomass, yield, and NUE. The root morphological traits and the N assimilation enzymatic acitivities play critical roles in regulating N accumulation and internal N translocation under the N-starvation stress, respectively. They can be used as morphological and biochemical references for evaluation of UpE and UtE in wheat.

关键词： wheat (Triticum aestivum L.) low and high N biomass yield nitrogen use efficiency root morphological traits,N assimilzation-associated enzyme photosynthetic rate