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On the Effect of Ghost Force in the Quasicontinuum Method:Dynamic Problems in One Dimension

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Communications in Computational Physics 2014年第3期15卷 647-676页

作者： xiantao li Pingbing Ming Department of Mathematics the Pennsylvania State UniversityUniversity ParkPennsylvania16802USA LSEC Institute of Computational Mathematics and Scientific/Engineering ComputingAMSSChinese Academy of SciencesNo.55East Road Zhong-Guan-CunBeijing100190P.R.China

Numerical error caused by“ghost forces”in a quasicontinuum method is studied in the context of dynamic *** error in the discrete W^(1,∞)norm is analyzed for the time scale O(ε)and the time scale O(1)withεbeing th... 详细信息

关键词： Quasicontinuum methods ghost force dynamic problems

An Effective and Easy-to-Implement Boundary Condition for Molecular Dynamics Simulations

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Communications in Computational Physics 2019年第6期26卷 192-205页

作者： Cheng Yuan Jerry Zhijian Yang xiantao li School of Mathematics and Statistics Wuhan UniversityWuhanHubei 430072P.R.China Hubei Key Laboratory in Computational Mathematics(Wuhan University) WuhanHubei 430072P.R.China Department of Mathematics The Pennsylvania State UniversityUniversity ParkPA 16802USA.

This paper presents an absorbing boundary condition for molecular dynamics simulations of materials *** purpose of the boundary condition is to eliminates spurious reflections of phonons at the boundary and minimize the finite size *** contrast to other existing methods,our emphasis is placed on the ease of *** particular,we propose a method for which the implementation can be done within existing molecular dynamics code,and it is insensitive to lattice structure,the geometry and space dimension of the computational *** demonstrate the effectiveness,the results from two test problems are presented.

关键词： Molecular dynamics boundary conditions dislocation crack Krylov space

Midterm results of periprosthetic coiling embolization in high-risk patients

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Journal of Interventional Medicine 2019年第4期2卷 160-163页

作者： xiantao li Yanyan Huang Pingfan Guo Vascular Surgery Department The First Affiliated Hospital of Fujian Medical UniversityFuzhouChina

Background:With increasing interest in the prevention of typeⅡendoleaks(EⅡ),the aim of this study was to report midterm results on the intraoperative coiling embolization of the periprosthetic aneurysmal sac in patients at high-risk of EⅡ.Methods:A retrospective review study was conducted with 124 patients with infrarenal abdominal aortic aneurysm who accorded with the inclusion criteria,including 66 patients who underwent standard endovascular aortic aneurysm repair(Group A)and 58 patients who underwent aneurysmal sac coiling embolization(Group B).Baseline data and follow-up results were ***:A mean of 2.84±1.45 coils(range 1-9)were used in Group *** general incidence of an EⅡwas 15.32%(19/124)at a mean follow-up time of 46.60±15.14 months,with 22.7%(15/66)in Group A and 6.9%(4/58)in Group B(χ~2=5.62;P=0.018).Logistic multivariate analysis revealed that the independent risk factors of an EII were no sac embolization and a sac volume≥128 cm^*** Kaplan-Meier subgroup analysis showed no difference in regard to the rate of freedom from EⅡbetween the two groups either with a larger or smaller ***:These results suggest that periprosthetic coiling embolization in patients at high-risk of EⅡis safe and effective in the prevention of EⅡ.The preventive effect seemed to be weakened when the sac volumes were taken into consideration at midterm follow-up.

关键词： Aortic aneurysm Abdominal Radiology Interventional Endoleak Risk assessment

Heterogeneous Multiscale Methods: A Review

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Communications in Computational Physics 2007年第3期2卷 367-450页

作者： Weinan E Bjorn Engquist xiantao li Weiqing Ren Eric Vanden-Eijnden Department of Mathematics and Program in Applied and Computational Mathematics Princeton UniversityPrincetonNJ 08544USA Department of Mathematics The University of Texas at AustinAustinTX 78712USA Department of Mathematics Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Mathematics Courant Institute of Mathematical SciencesNew York UniversityNew YorkNY 10012USA.

This paper gives a systematic introduction to HMM,the heterogeneous multiscale methods,including the fundamental design principles behind the HMM philosophy and the main obstacles that have to be overcome when using HMM for a particular *** is illustrated by examples from several application areas,including complex fluids,micro-fluidics,solids,interface problems,stochastic problems,and statistically self-similar *** is given to the technical tools,such as the various constrained molecular dynamics,that have been developed,in order to apply HMM to these *** of mathematical results on the error analysis of HMM are *** review ends with a discussion on some of the problems that have to be solved in order to make HMM a more powerful tool.

关键词： Multi-scale modeling heterogeneous multi-scale method multi-physics models constrained micro-scale solver data estimation.

The Development of Chinese Cultivation of New Curriculum Reform

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International English Education Research 2015年第2期 36-37页

作者： li xiantao Canghai Senior Middle School Wuzhou Guangxi Zhuang Autonomous Region China

Chinese language teaching in new curriculum reform not only inherits and develops the old teaching mode, but also teaches the spirit of Chinese in the curriculum reform and cultivates the students＇ Chinese cultivation. This article mainly deals with the cultivation of Chinese self-restraint under the background of new curriculum reform, according to students＇ self - cultivation, emotion and rational interest.

关键词： students' self- cultivation emotion rational interest

Application Strategy of Panoramic Technology in Environmental Field Investigation

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Journal of Electronic Research and Application 2022年第3期6卷 20-25页

作者： Bin Zhang lin Zhu xiantao li Beijing Zhongqi Jingcheng Environmental Technology Co. Ltd.Beijing 100086China

In order to improve the efficiency and quality of environmental field investigation,as well as realize real-time image data information sharing between the field environment and the investigation center,this paper first analyzes the application advantages of panoramic technology,followed by the types of panoramic technology,and finally takes the UAV panoramic technology as an example to demonstrate the application process of panoramic technology in environmental field investigation for the reference of relevant personnel.

关键词： UAV panoramic technology Environmental investigation Sphere panorama

Regeneration of waste sintered Nd-Fe-B magnets to fabricate anisotropic bonded magnets

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Journal of Rare Earths 2015年第7期33卷 736-739页

作者：李现涛岳明 ZAKOTNIK Miha 刘卫强张东涛左铁镛 College of Materials Science and Engineering Beijing University of Technology

The waste sintered Nd-Fe-B magnets were regenerated as magnetic powders via manually crushing （MC） or hydrogen decrepitation （HD） to fabricate anisotropic bonded magnets. Effect of size distribution on the magnetic properties of the regenerated magnetic MC and HD powders was investigated. For the MC powders, as the particle size decreased, the remanence （Br） increased first, and then decreased again, while the coercivity （Hci） dropped monotonically. The powders with particle size in the range of 200-450μm possessed the best magnetic properties ofBr of 1.22 T and Hci of 875.6 kAJm. The corresponding bonded magnet exhibited magnetic properties ofBr of 0.838 T, Hci of 940.9 kA/m, and （BH）max of 91.4 kJ/m^3, respectively. On the other hand, the liD powders with particle size range of 200-450 μm bore the best magnetic properties Of Br of 1.24 T and Hci of 860.4 kA/m. Compared with magnetic properties of the waste magnet, the powders retained 93.9% of Br and 70.0% of Hci, respectively. The bonded magnet produced from HD powders possessed Br of 0.9 T, Hci of 841.4 kA/m, and （BH）max of 111.6 kJ/m^3, indicating its good potential in practical applications.

关键词： regeneration Nd-Fe-B magnet scraps hydrogen decrepitation anisotropic bonded magnets rare earths

Effects of nifedipine on outward Kv currents in N2A cells

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Effects of nifedipine on outward Kv currents in N2A cells

基于自适应鲁棒控制提升快速反射镜的抗扰能力

中国生理学会第24届全国会员代表大会暨生理学学术大会

作者： xiantao li Ximu Hu Xiaoqing li Xiaoyue Qiu Pengfei Ma Kai li 中南民族大学生命科学学院

It is well known that nifedipine inhibits L-type Ca2+channels expressed throughout the cardiovascular ***-dependent K+（Kv）channels belong to the same supergene family as Ca2+and Na+channels;therefore,these channels could be one of the targets of *** studies suggested that there existed macroscopic Kv currents in mouse neuroblastoma N2A *** the study here,whole-cell recording was performed to examine the actions of nifedipine on outward Kv currents in N2A *** to nifedipine,in a concentration-dependent manner,potently reduced the peak and steady-state currents through Kv *** depression in both the amplitude and the decay rate of Kv currents,with an increase in depolarization,suggested that it was a voltage-dependent *** activation and inactivation experiments were conducted to determine the exact causes of the inhibitory *** to nifedipine did not affect the half-maximum activation potential（V1/2）.For steady-state inactivation,the half-maximum inactivation potential（V1/2）was–45.0 m V and shifted right to–32.5 m V with a statistical difference and the time constants of recovery from inactivation were also altered by nifedipine,suggesting that the depression was correlated with the inactivation gate.

关键词： Nifedipine N2A cells Kv currents

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中国激光 2019年第9期46卷 196-203页

作者：王正玺张葆李贤涛中国科学院长春光学精密机械与物理研究所航空光学成像与测量重点实验室吉林长春130033 中国科学院大学北京100049

航空光电稳定平台广泛采用快速反射镜进行视轴稳定,航空环境中的各种扰动,尤其是振动会影响快速反射镜的稳定性能。针对传统的抗扰方法[如比例-积分-微分控制器(PID)、干扰观测器(DOB)等]抑制扰动效果不明显的问题,提出一种基于自适应... 详细信息

航空光电稳定平台广泛采用快速反射镜进行视轴稳定,航空环境中的各种扰动,尤其是振动会影响快速反射镜的稳定性能。针对传统的抗扰方法[如比例-积分-微分控制器(PID)、干扰观测器(DOB)等]抑制扰动效果不明显的问题,提出一种基于自适应鲁棒控制(ARC)方法的快速反射镜抗扰策略。实验测试发现,引入ARC以后,快速反射镜在振动环境中的稳态均方根误差值相比于PID降低约80%,相比于DOB降低约60%,表明ARC对于提升快速反射镜的抗扰能力和稳定性能具有显著效果,具有较大的工程应用价值。

关键词：机器视觉快速反射镜扰动干扰观测器自适应鲁棒控制