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Field-Free Molecular Orientation Induced by Nonresonant Square Laser Pulses

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Chinese Physics Letters 2011年第4期28卷 83-86页

作者： xu Shu-Wu HUANG Yun-Xia ji Xian-ming School of Science Nantong UniversityNantong 226007

We propose a scheme to achieve field-free molecular orientation by a nonresonant square laser *** CO molecules as an example,we show that,differing from the conventional Gaussian pulse,field-free molecular orientation excited by square pulses can be realized in both nonadiabatic and adiabatic *** also show that the maximum degree of the molecular orientation can be further enhanced by separating one square pulse into two time delayed subpulses and by applying the second subpulse at the beginning of the rotational wave packet rephrasing created by the first subpulse and the optimal intensity ratio between the two subpulses is about I_(1)/I_(2)=1:1.5.

关键词： pulse separating Pulse

Sharp Upper and Lower Bounds for the Laplacian Spectral Radius and the Spectral Radius of Graphs

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 289-296页

作者： ji-ming Guo Department of Applied Mathematics China University of Petroleum Dongying 257061 China

In this paper, sharp upper bounds for the Laplacian spectral radius and the spectral radius of graphs are given, respectively. We show that some known bounds can be obtained from our bounds. For a bipartite graph G, w... 详细信息

关键词： Graph Laplacian spectral radius spectral radius upper (lower) bound bipartite graph eigen-vector

Dispersive Property of Mode Grüneisen Parameter:Corundum andα-Quartz as Examples

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Chinese Physics Letters 1999年第4期16卷 249-250页

作者： xu ji-an Institute of Earth Sciences Academia SinicaNankang P.O.Box 1-55TaipeiTaiwan

The dispersive property of the mode Grüneisen parameter in solids is found *** a property should appear in a reciprocal relationship to the mode *** phenomenon is also confirmed experimentally in the cases of corundu... 详细信息

关键词： Grüneisen property Quartz

Confirming the 115.5-day periodicity in the X-ray light curve of ULX NGC 5408 X-1

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Research in Astronomy and Astrophysics 2012年第12期12卷 1597-1602页

作者： xu Han Tao An Jun-Yi Wang ji-ming Lin ming-jie Xie Hai-Guang xu Xiao-Yu Hong Sandor Frey Key Laboratory of Cognitive Radio & Information Processing Ministry of Education Guilin University of Electronic Technology Guilin 541004 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China School of Mathematics and Computational Science Xiangtan University Xiangtan 411105China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing 210008 China Department of Physics Shanghai Jiao Tong University Shanghai 200240 China FOMI Satellite Geodetic Observatory EO. Box 585 H-1592 Budapest Hungary

The Swift/XRT light curve of the ultraluminous X-ray source NGC 5408 X-1 was re-analyzed with two new numerical approaches, the Weighted Wavelet Ztransform and CLEANest, and the results are different from previous studies. Both techniques detected a prominent periodicity with a time scale of 115.5 ± 1.5 days, in excellent agreement with the detection of the same periodicity first reported by Strohmayer . Monte Carlo simulations were employed to test the statisitical confidence of the 115.5-day periodicity, yielding a statistical significance of 〉 99.98% （or 〉 3.8σ）. The robust detection of the 115.5-day quasi-periodic oscillations, if they are due to the orbital motion of the binary, would infer a mass of a few thousand M⊙ for the central black hole, implying there is an intermediate-mass black hole in NGC 5408 X-1.

关键词： methods: statistical - galaxies: individual (NGC 5408) - stars: oscil- lations

SbCl_3 Catalyzed Solventless Synthesis of Bis(indolyl)alkanes under Grinding

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Chemical Research in Chinese Universities 2009年第6期25卷 941-944页

作者： ZHANG ji-ming xu Rui-ping TIAN Yan ZHOU jian-hua School of Chemical Engineering Shandong Institute of Light Industry Jinan 250353 P. R. China School of Chemistry and Chemical Engineering Shandong University Jinan 250100 P. R. China

A clean and efficient method for the synthesis of bis（indolyl）alkanes with antimony trichloride（SbCl3） as the catalyst under solvent-free grinding conditions is described. This method provides several advantages, ... 详细信息

关键词： Bis(indolyl)alkane Indole SbCl3 Grinding

机器学习预测肱骨近端骨折钢板内固定后继发性螺钉切出的风险

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中国组织工程研究 2025年第15期29卷 3179-3187页

作者：徐大星涂泽松纪木强许伟鹏牛维广州中医药大学广东省广州市510006 佛山市中医院三水医院骨科广东省佛山市528100 佛山市中医院骨科广东省佛山市528000 广东省中医院关节外科广东省广州市510120

背景:继发性螺钉切出关节面是肱骨近端骨折锁定钢板内固定术后的主要并发症之一,切出的螺钉会磨损关节盂和引起肩峰撞击,影响肩关节功能。因此,准确的风险预测有积极的临床意义。目的:通过机器学习方法筛选肱骨近端骨折钢板内固定后继... 详细信息

背景:继发性螺钉切出关节面是肱骨近端骨折锁定钢板内固定术后的主要并发症之一,切出的螺钉会磨损关节盂和引起肩峰撞击,影响肩关节功能。因此,准确的风险预测有积极的临床意义。目的:通过机器学习方法筛选肱骨近端骨折钢板内固定后继发性螺钉切出的风险因素,开发并验证风险预测模型,便于临床医生早期甄别并干预高风险患者。方法:收集2013年6月至2022年6月接受锁定钢板内固定治疗的214例肱骨近端骨折患者的临床资料作为训练组建立模型,将同一时间段另一医院收治的同类患者61例纳入外部验证组。按照患者术后是否出现继发性螺钉切出,分为螺钉切出组和螺钉维持组。训练组利用随机森林、支持向量机、逻辑回归3种机器学习算法构建预测模型;采用递归特征消除法、10折交叉验证重抽样作为变量的筛选方法,并将3种模型准确度最高时纳入变量的交集作为与螺钉切出高度相关的可靠风险变量。通过R语言软件构建动态预测模型,以网页计算器形式展示,并对模型进行内、外部验证。模型内部检验采用Bootstrap法重抽样1000次,使用受试者工作特征曲线下面积、校准曲线、临床决策曲线评价模型的区分度、校准能力及临床应用价值。通过Youden指数确定预测模型的最佳风险分界值,据此将外部验证组患者分为高、低风险组,根据模型风险预测能力的准确度来评价其稳定性和外延性。结果与结论:①机器学习算法筛选出继发性螺钉切出高度相关的4个风险变量,分别为肱骨近端内侧柱皮质支撑、三角肌结节指数、骨折类型及术后复位情况;②构建的风险预测模型表现出良好的区分度和准确度[曲线下面积=0.874,95%置信区间(0.827,0.922)],校准曲线显示模型预测风险和实际发生风险有较好的一致性;③临床决策曲线提示风险阈值概率在0.1-0.75范围内时,模型具有较好的临床适用性;④风险概率为26%是模型风险分层的最佳阈值,外部验证组利用模型风险分层预测螺钉切出的总正确率为84%;⑤结果说明该风险预测模型准确度和外延性较好,可为指导临床治疗提供依据。

关键词：肱骨近端骨折继发性螺钉切出机器学习影响因素风险预测模型

Magnetoelectroelastic fields in rotating multiferroic composite cylindrical structures

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 319-326页

作者： ji YING Hui-ming WANG Department of Mechanical Engineering Zhejiang University Hangzhou 310027 China Department of Mechanics Zhejiang University Hangzhou 310027 China

An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the nu-merical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable.

关键词： Analytical solution Multiferroic composite Rotating hollow cylinder State space method

Displaced orbits generated by solar sails for the hyperbolic and degenerated cases

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Acta Mechanica Sinica 2012年第1期28卷 211-220页

作者： ming xu Shi-jie xu Department of Aerospace Engineering School of AstronauticsBeihang University100191 BeijingChina

Displaced non-Keplerian orbits above planetary bodies can be achieved by orientating the solar sail normal to the sun line. The dynamical systems techniques are employed to analyze the nonlinear dynamics of a displaced orbit and different topologies of equilibria are yielded from the basic configurations of Hill＇s region, which have a saddlenode bifurcation point at the degenerated case. The solar sail near hyperbolic or degenerated equilibrium is quite unstable. Therefore, a controller preserving Hamiltonian structure is presented to stabilize the solar sail near hyperbolic or degenerated equilibrium, and to generate the stable Lissajous orbits that stay stable inside the stabilizing region of the controller. The main contribution of this paper is that the controller preserving Hamiltonian structure not only changes the instability of the equilibrium, but also makes the modified elliptic equilibrium become unique for the controlled system. The allocation law of the controller on the sail＇s attitude and lightness number is obtained, which verifies that the controller is realizable.

关键词： Solar sail Displaced orbit Stable Lissajous orbits Hyperbolic equilibrium Degenerated equilibrium

Thermodynamic properties of two-dimensional charged spin-1/2 Fermi gases

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Chinese Physics B 2022年第6期31卷 254-259页

作者： jia-Ying Yang xu Liu ji-Hong Qin Huai-ming Guo Department of Physics University of Science and Technology BeijingBeijing 100083China Institute of Theoretical Physics University of Science and Technology BeijingBeijing 100083China Department of Physics Beihang UniversityBeijing 100191China

Based on the mean-field theory,we investigate the thermodynamic properties of the two-dimensional(2D)charged spin-1/2 Fermi ***′factor g is introduced to measure the strength of the paramagnetic *** is a competition between diamagnetism and paramagnetism in the *** larger the Lande′factor,the smaller the entropy and specific *** tends to increase the entropy,while paramagnetism leads to the decrease of the *** find that there exists a critical value of Lande′factor for the transition point due to the *** entropy of the system increases with the magnetic field when g0.58,the entropy first decreases with the magnetic field,then reaches a minimum value,and finally increases *** the entropy and specific heat increase with the temperature,and no phase transition *** specific heat tends to a constant value at the hightemperature limit,and it approaches to zero at very low temperatures,which have been proved by the analytical calculation.

关键词： Fermi gas entropy specific heat Landéfactor