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Diffusion of an Extra Ga Atom in GaAs（001）（2×4） Rich-As Surface

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Chinese Journal of Chemical Physics 2008年第1期21卷 69-75页

作者： kun li Bi-cai Pan College of Physics and Engineering Qufu Normal University Qufu 273165 China Hefei National Laborator7 for Physical Sciences at Microscale Department of Physics University ofScience and Technology of China Hefei 230026 China

The potential energy surface for the migration of an extra Ga atom on the GaAs（001） β2（2×4） surfuce was mapped out by performing calculations at the level of analytical bond-order potential. Based on this calculations, we found some lower-energy sites for the adsorption of an extra Ga atom in the surface, which were in agreement with the experimental data. Moreover, many possible pathways for an extra Ga atom diffusing in this surface were revealed. According to the relative energies of the possible pathways, the individual Ga adatoms preferably keep their diffusion in two pathways parallel to the As dimers. This result can be understood using the strain caused by the diffusing Ga atom in the pathways. In addition, the simulated kinetic processes of the extra Ga atom diffusing in different pathways at finite temperatures support the prediction from our calculated potential energy surface.

关键词： Surface Adsorption Diffusion of an atom Molecular-dynamics simulation

Estimates on the eigenvalues of complex nonlocal Sturm-liouville problems

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Applied Mathematics(A Journal of Chinese Universities) 2023年第1期38卷 100-110页

作者： SUN Fu li kun School of Statistics and Data Science Qufu Normal UniversityQufu 273165China School of Mathematical Sciences Qufu Normal UniversityQufu 273165China School of Mathematics and Statistics Shandong UniversityWeihai 264209China

The present paper deals with the eigenvalues of complex nonlocal Sturm-liouville boundary value *** bounds of the real and imaginary parts of eigenvalues for the nonlocal Sturm-liouville differential equation involving complex nonlocal potential terms associated with nonlocal boundary conditions are obtained in terms of the integrable conditions of coefficients and the real part of the eigenvalues.

关键词： Sturm-liouville problem nonlocal potential complex valued coefficient non-real eigenvalue

The Eulerian-Lagrangian Method with Accurate Numerical Integration

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Advances in Applied Mathematics and Mechanics 2012年第2期4卷 156-174页

作者： kun li LMAM&School of Mathematical Sciences Peking UniversityBeijing 100080China

This paper is devoted to the study of the Eulerian-Lagrangian method(ELM)for convection-diffusion equations on unstructured grids with or without accurate numerical *** first propose an efficient and accurate algorithm to calculate the integrals in the Eulerian-Lagrangian *** approach is based on an algorithm for finding the intersection of two non-matching *** has optimal algorithmic complexity and runs fast enough to make time-dependent velocity fields *** evaluation of the integrals leads to increased precision and the unconditional *** demonstrate by numerical examples that the ELM with our proposed algorithm for accurate numerical integration has the following two features:first it is much more accurate and more stable than the ones with traditional numerical integration techniques and secondly the overall cost of the proposed method is comparable with the traditional ones.

关键词： Eulerian-Lagrangian method intersection of non-matching grids exact integration

Facies-constrained prestack seismic probabilistic inversion driven by rock physics

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Science China Earth Sciences 2020年第6期63卷 822-840页

作者： kun li Xingyao YIN Zhaoyun ZONG School of Geosciences China University of Petroleum(East China)Qingdao 266580China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

Seismic Rock physics plays a bridge role between the rock moduli and physical properties of the hydrocarbon *** seismic inversion is an important method for the quantitative characterization of elasticity,physical properties,lithology and fluid properties of subsurface *** this paper,a high order approximation of rock physics model for clastic rocks is established and one seismic AVO reflection equation characterized by the high order approximation(Jacobian and Hessian matrix)of rock moduli is ***,the contribution of porosity,shale content and fluid saturation to AVO reflectivity is *** feasibility of the proposed AVO equation is discussed in the direct estimation of rock physical *** the basis of this,one probabilistic AVO inversion based on differential evolution-Markov chain Monte Carlo stochastic model is proposed on the premise that the model parameters obey Gaussian mixture probability prior *** stochastic model has both the global optimization characteristics of the differential evolution algorithm and the uncertainty analysis ability of Markov chain Monte Carlo *** the cross parallel of multiple Markov chains,multiple stochastic solutions of the model parameters can be obtained simultaneously,and the posterior probability density distribution of the model parameters can be simulated *** posterior mean is treated as the optimal solution of the model to be ***,the variance and confidence interval are utilized to evaluate the uncertainties of the estimated results,so as to realize the simultaneous estimation of reservoir elasticity,physical properties,discrete lithofacies and dry rock *** validity of the proposed approach is verified by theoretical tests and one real application case in eastern China.

关键词： Prestack seismic inversion Seismic rock physics Physical properties estimation Bayesian inference Probabilistic mixture model Markov chain Monte Carlo

Feeling Hot and Cold:Thermal Sensation in Drosophila

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Neuroscience Bulletin 2017年第3期33卷 317-322页

作者： kun li Zhefeng Gong Department of Neurobiology Key Laboratory of Medical Neurobiology of the Ministry of Health of ChinaZhejiang University School of MedicineHangzhou 310058China

Sensing environmental temperature is crucial for animal *** model animal,Drosophila melanogaster,can be investigated with a large number of genetic tools,which have greatly facilitated studies of the cellular and molecular mechanisms of thermal *** the molecular level,a group of proteins,including Transient Receptor Potential channels and ionotropic receptors,have been characterized as potential thermal sensors in both larval and adult *** the cellular and circuit levels,peripheral and central thermosensory neurons have been *** interestingly,thermal information has been found to be specifically encoded by specific central *** this short review,we mainly survey the progress in understanding the molecular mechanisms of thermosensation and the neuronal mechanisms of thermal information processing in the brain of *** recent temperature-related findings such as its impact on neurosecretion and thermotactic behavior in Drosophila are also introduced.

关键词： Drosophila Temperature Thermal sensation

13-18岁青少年颈椎关节突关节发育特征的数字化三维形态分析

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中国组织工程研究 2025年第21期29卷 4486-4491页

作者：李贵花和雨洁史君李琨张少杰刘路李志军王星内蒙古自治区监狱管理局第一医院内蒙古自治区呼和浩特市010000 内蒙古医科大学基础医学院解剖学教研室内蒙古自治区呼和浩特市010110 内蒙古医科大学基础医学院生理学教研室内蒙古自治区呼和浩特市010110 内蒙古医科大学基础医学院数字医学中心内蒙古自治区呼和浩特市010110

背景:颈椎关节突关节作为颈椎后柱的重要解剖结构,在颈部活动、应力传导以及维持颈椎稳定性中发挥重要的作用。近年来通过解剖学和生物力学研究表明,颈椎关节突关节不对称可引起关节突关节的退变,颈椎关节突关节的退变可能是引起青年人... 详细信息

背景:颈椎关节突关节作为颈椎后柱的重要解剖结构,在颈部活动、应力传导以及维持颈椎稳定性中发挥重要的作用。近年来通过解剖学和生物力学研究表明,颈椎关节突关节不对称可引起关节突关节的退变,颈椎关节突关节的退变可能是引起青年人颈椎退变的主要原因。现有研究多集中在成人,国内对于学龄前儿童、学龄期儿童也有报道,而对于青少年颈椎小关节形态相关参数鲜有报道。目的:通过三维重建青少年颈椎关节突关节,测量其相关形态参数,并与儿童和成年人进行比较分析,探讨颈椎小关节形态发育的增龄变化规律,为临床颈椎小关节源性颈椎病的诊治和预防提供理论依据。方法:选择13-18岁青少年62例,行颈椎螺旋CT扫描后三维重建,要求无骨质破坏、肿瘤、畸形、骨折等,椎骨形态结构未发生改变,既往无脊柱相关手术,监护人对试验方案知情同意。按年龄分组,A组年龄为13-14岁,B组年龄为15-16岁,C组年龄为17-18岁。对各组青少年进行C_2-C_7关节突关节相关形态测量及统计分析。结果与结论:(1)3组关节突关节面高和关节面宽在随椎序的变化中,分别呈递减和递增趋势,下关节突关节面的高和宽均大于上关节面的相应指标;(2)关节突关节内高在3组年龄中,最小值均位于C5,且与年龄呈正相关变化;(3)关节突关节面间隙在3组中,A组C_(4-5)、B组C_(3-4)和C组C_(4-5)明显大于各组其余间隙;A、B组除C_(4-5)外,其余无显著性差异;C组除C_(2-3)其余椎序间关节面间隙均明显大于A、B组;(4)提示颈椎关节突关节面的形态随椎序的增加,逐渐由圆形过渡到椭圆形;在组间比较中,关节面高较关节面宽受年龄影响明显;各节段下关节面的面积均大于上关节面的面积,仅在C_(4-5)和C_(5-6)形态和面积有显著性差异;加之关节突关节内高最小值均位于C5,关节突关节面间隙明显增宽处也主要位于C_(3-4)和C(_4-5),因此颈椎失稳多发生于中位节段。

关键词：青少年颈椎关节突关节数字化形态三维重建

The existence of traveling wave solutions in an integro-difference competition-cooperation system

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International Journal of Biomathematics 2018年第1期11卷 203-224页

作者： kun li Xiong li School of Mathematics and Computational ScienceHunan First Normal University Changsha 510205 P. R. China School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education Beijing 100875 P. R. China

In this paper, we are devoted to establishing the existence of traveling wave solutions in an integro-difference competition-cooperation system with partial monotonieity by using Schauder＇s fixed point theorem, the cross-iteration and the upper and lower solutions method. To illustrate our result, we present an application to integrodifference competition-cooperation system with a special kernel by constructing a pair of upper and lower solutions, while the verification of upper and lower solutions is nontrivial.

关键词： Integro-difference competition-cooperation system traveling wave solution Schauder's fixed point theorem cross-iteration scheme upper and lower solutions.

Role of hydrogen in the dissociation of CH4 on different graphene by DFT study

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Chinese Journal of Aeronautics 2022年第6期35卷 407-419页

作者： kun li Hejun li Ni li Qiang SONG Lehua QI State Key Laboratory of Solidification Processing Carbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

The effect of hydrogen on the growth mechanism of pyrocarbon has attracted much attention. The influence of hydrogen on the dissociation from CH4to C2H2on pristine graphene,N-doped graphene and vacancy graphene have been investigated by using density functional *** are two kinds of heterogeneous reaction pathways when the hydrogen is involved, i.e., dehydrogenation reactions and H-abstraction reactions. The transition state calculations were performed to acquire the reaction pathways on each substrate after obtaining the most stable adsorption configurations of the reactants and products. The results indicate that the adsorptions of reactants are not affected by hydrogen. The dehydrogenation reactions are more favored on vacancy graphene, and the H-abstraction reactions are more favored on the pristine graphene and N-doped graphene. The dehydrogenation reactions on the vacancy graphene are most favored among all these reactions in favor of the deposition of pyrocarbon. The dehydrogenation reactions on these three substrates are affected by hydrogen.

关键词： Abstraction Dehydrogenation DFT Graphene Hydrogen Methane

Stagnant low-energy ions in the near cusp region observed by Cluster

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Science China Earth Sciences 2017年第7期60卷 1299-1309页

作者： li kun WEI Yong WAN WeiXing Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Lunar and Planetary Science Laboratory Macao University of Science and Technology-Partner Laboratory of Key Laboratory of Lunar and Deep Space Exploration Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences

Measuring the low-energy ions in the Earth's magnetotail lobes is difficult, because a spacecraft becomes positively charged in a sunlit and tenuous plasma environment. Recent studies have introduced a new method, making use of the positive electric potential on the Cluster spacecraft, to measure the low-energy ions(less than a few tens of electronvolts) in the polar caps/magnetotail lobes in the years 2001–2010. With the measured velocities, we are able to study the trajectories of these low-energy ions. Particle tracing has been used in previous studies, confirming that ions of ionospheric origin are the dominant contributor to the ion population in the Earth's magnetotail lobes. In this work, we continue to study the source of low-energy ions measured in the lobes. We found that not all of the low-energy ions in the lobes come directly from the ionosphere. Particle tracing infers that some of the low-energy ions start to move tailward from the cusp/near-cusp region with a zero parallel velocity. In the following, we refer to these low-energy ions as stagnant low-energy ions. On the other hand, the in situ measurements by Cluster show a population of low-energy ions in the cusp/near-cusp region with pitch angles near 90°(i.e., no significant parallel velocity).The locations of stagnant low-energy ions are determined by particle tracing and in situ measurements. Similar ion energies and spatial distributions determined by these two methods confirm the presence of the stagnant low-energy ion population.

关键词： Ionospheric outflow Low-energy ion Potential energy balance Ion stagnation