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Reactions of Laser Ablation-magnesium Plasma with Methanol Clusters

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Chemical Research in Chinese Universities 2006年第5期22卷 621-625页

作者： ZHANG Shu-dong KONG Xiang-he ZHU Xiang-jun WANG Yan jiang su-rong College of Physics and Engineering Qufu Normal University Qufu 273165 P. R. China

The laser ablation-molecular beam（LA-MB） method is useful for studying the reactions of metal ions with molecular clusters. Reactions of magnesium plasma with methanol clusters were studied by using this method. A specially designed reaction cell was used as a fast flow reactor operated under thermal conditions, and the reaction products were measured with a time-of-flight（TOF） mass spectrometer. surprisingly, several series of cluster ions with complex sizes and intensity distributions were obtained when the laser ablating was applied to different parts of the molecular beam. In the front part of the molecular beam, strong Mg^＋（CH3OH）n（ n = 0-5） and weak H^＋（CH3OH）n（ n = 0-5 ） cluster ions were observed with relatively small cluster sizes ; in the middle part of the molecular beam, the main cluster ions were H^＋（ CH3OH）n （ n = 6-17 ） and H^＋（ H2O） 2 （ CH3OH）n（ n = 6-17 ） with a relatively large cluster size and a weak intensity; in the back part of the molecular beam, two new series of cluster ions, MgO^＋（ H2O）（ CH3 OH）n（ n = 6-10 ） and MgOCH3^＋（ CH3OH）n（ n = 6-10）, were obtained and accompanied by weak H^＋（CH3OH）n（n = 4-7） and H^＋（ H2O）2 （CH3OH）n（ n = 3-6）. The formation mechanisms and speed characteristics of the cluster ions are discussed in this article.

关键词： Laser ablation-molecular beam Mg plasma Methanol cluster Ion-molecular cluster reaction Formation mechanism

Heat shock protein 27 regulates oxidative stress-induced apoptosis in cardiomyocytes:mechanisms via reactive oxygen species generation and Akt activation

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Chinese Medical Journal 2007年第24期120卷 2271-2277页

作者： LIU Li ZHANG Xiao-jin jiang su-rong DING Zheng-nian DING Guo-xian HUANG Jun CHENG Yun-lin Departments of Geriatrics First Affiliated Hospital of Nanjing Medical University Nanjing 210029 China Department of Anaesthesiology First Affiliated Hospital of Nanjing Medical University Nanjing 210029 China Department of Cardiology First Affiliated Hospital of Nanjing Medical University Nanjing 210029 China

Background Increased reactive oxygen species （ROS） formation, which in turn promotes cardiomyocytes apoptosis, is associated with the pathogenesis and progression of various cardiac diseases such as ischemia and heart failure. Recent studies have shown that over expression of heat shock protein 27 （Hsp27） confers resistance to cardiac ischemia/reperfusion injury. However, not much is known about the regulation of myocyte survival by Hsp27. Methods The rat cardiac cell line H9c2, with a stable overexpression of Hsp27, was established, with empty vector transfected H9c2 cells as controls. Following the cells challenged by Hydrogen Peroxide （H2O2）, lactate dehydrogenase （LDH） release, apoptosis, intracellular ROS, cell morphology, mitochondrial transmembrane potential and the activation of serine/threonine kinase Akt were determined. Results Along with marked suppression of H2O2-induced injury by Hsp27 overexpression in H9c2 cells, ROS generation and the loss of mitochondrial membrane potential were also significantly depressed. Furthermore, augmented Akt activation was observed in Hsp27 overexpressed H9c2 cells following H2O2 exposure. Conclusions Hsp27 inhibits oxidative stress-induced H9c2 damage and inhibition of ROS generation and the augmentation of Akt activation may be involved in the protective signaling.

关键词： heat shock protein 27 apoptosis superoxide mitochondrial potential Akt

Hybrid Block Diagonalization Precoding for Multi-User Weighted sum-Rate Maximization

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China Communications 2024年第8期21卷 127-141页

作者： su Xiaofeng jiang Yi Key Laboratory for Information Science of Electromagnetic Waves(MoE) Department of Communication Science and EngineeringFudan UniversityShanghai 200433China

This paper studies large-scale multi-input multi-output(MIMO)orthogonal frequency division multiplexing(OFDM)communications in a broadband frequency-selective channel,where a massive MIMO base station(BS)communicates with multiple users equipped with *** develop a hybrid precoding design to maximize the weighted sum-rate(WSR)of the users by optimizing the digital and the analog precoders *** the digital part,we employ block-diagonalization to eliminate inter-user interference and apply water-filling power allocation to maximize the *** the analog part,the optimization of the PSN is formulated as an unconstrained problem,which can be efficiently solved by a gradient descent *** results show that the proposed block-diagonal hybrid precoding algorithm can outperform the existing works.

关键词： block-diagonal gradient descent hybrid precoding iterative optimization MIMO-OFDM multi-user water-filling power allocation weighted sum-rate maximization

Bézier曲线到Wang-Ball曲线的转换矩阵及其应用

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计算机学报 2005年第1期28卷 75-80页

作者：蒋素荣王国瑾浙江大学计算机图像图形研究所杭州310027 浙江大学CAD&CG国家重点实验室杭州310027

Wang Ball曲线作为一种广义Ball曲线已经在参数曲线求值、升降阶计算中显示出极其有效的作用 .为了在几何设计中更好地发挥其作用 ,应当用简单的方法求出Bernstein基到Wang Ball基的转换矩阵 .该文借助于一个多项式的展开算法 ,给出了... 详细信息

Wang Ball曲线作为一种广义Ball曲线已经在参数曲线求值、升降阶计算中显示出极其有效的作用 .为了在几何设计中更好地发挥其作用 ,应当用简单的方法求出Bernstein基到Wang Ball基的转换矩阵 .该文借助于一个多项式的展开算法 ,给出了这个转换矩阵 ,即给出了B啨ｚｉｅｒ曲线到Ｗａｎｇ Ball曲线的转换公式 ,并应用它简捷地推导出n次Wang Ball曲线的中点离散公式 .

关键词：广义Ball曲线 Bézier曲线离散转换矩阵

Primordial black holes and curvature perturbations from false vacuum islands

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： rong-Gen Cai Yu-Shi Hao Shao-jiang Wang School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific Center for Theoretical Physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions will accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island with thus acquired density contrast of a super-horizon size will evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow large enough to exceed the threshold of gravitational collapse,primordial black holes will form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,we revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions with fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations

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A Quantitative Seismic Topographic Effect Prediction Method Based upon BP Neural Network Algorithm and FEM Simulation

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Journal of Earth Science 2024年第4期35卷 1355-1366页

作者： Qifeng jiang Mianshui rong Wei Wei Tingting Chen Shandong Seismic Hazard Prevention Center Shandong Earthquake AgencyJinan250014China Shandong Institute of Earthquake Engineering Jinan250021China Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education Beijing University of TechnologyBeijing100124China Publicity and Education Center Shandong Earthquake AgencyJinan250014China Shandong Earthquake Station Shandong Earthquake AgencyJinan250014China

Topography can strongly affect ground motion,and studies of the quantification of hill surfaces’topographic effect are relatively *** this paper,a new quantitative seismic topographic effect prediction method based upon the BP neural network algorithm and three-dimensional finite element method(FEM)was *** FEM simulation results were compared with seismic records and the results show that the PGA and response spectra have a tendency to increase with increasing elevation,but the correlation between PGA amplification factors and slope is not obvious for low *** BP neural network models were established for the prediction of amplification factors of PGA and response *** kinds of input variables’combinations which are convenient to achieve are proposed in this paper for the prediction of amplification factors of PGA and response spectra,*** absolute values of prediction errors can be mostly within 0.1 for PGA amplification factors,and they can be mostly within 0.2 for response spectra’s amplification *** input variables’combination can achieve better prediction performance while the other one has better expandability of the predictive ***,the BP models only employ one hidden layer with about a hundred nodes,which makes it efficient for training.

关键词： seismic topographic effect finite element method BP neural network algorithm earthquake disaster prevention

Shock-induced chemical reaction characteristics of PTFE-Al-Bi_(2)O_(3)reactive materials

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Defence Technology（防务技术） 2024年第6期36卷 1-12页

作者： Chunlan jiang rong Hu Jingbo Zhang Zaicheng Wang Liang Mao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

A ternary system of PTFE/Al/Bi_(2)O_(3)is constructed by incorporating PTFE-based reactive material and thermite for enhancing the energy release of the PTFE-based reactive *** effects of Bi_(2)O_(3)in the PTFE/Al/Bi_(2)O_(3)on both mechanical properties and the energy release were investigated through various tests such as thermogravimetry-differential scanning calorimetry,adiabatic oxygen bomb test and split Hopkinson pressure bar *** microstructure observed through scanning electron microscope and Xray diffraction results are used to analyze the ignition and reaction mechanism of PTFE/Al/Bi_(2)O_(3).The results indicate that the PTFE/Al/Bi_(2)O_(3)are capable of triggering the exothermic reaction of molten PTFE/Bi_(2)O_(3)and Al/Bi_(2)O_(3)over the PTFE/Al reactive materials,thereby promoting *** excessive aluminum in the ternary system is beneficial for increasing energy *** ignition of shock-induced chemical reactions in PTFE/Al/Bi_(2)O_(3)is closely related to the material *** dominant mechanism for hot-spot generation under Split Hopkinson Pressure Bar test is the frictional temperature rise at the microcrack after failure.

关键词： PTFE/Al/Bi_(2)O_(3) Shock-induced chemical reaction Energy release

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang rong Liu Jing-Yuan Liu Wen-Wei jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

用割角多边形产生Bernstein-Bézier曲线的更小包围域

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浙江大学学报（工学版） 2007年第6期41卷 941-944页

作者：章仁江王国瑾蒋素荣浙江大学计算机图像图形研究所南京航空航天大学数学系江苏南京210016

基于Bézier曲线的控制多边形，介绍了割角多边形的概念．割角多边形的顶点可以由控制多边形的顶点快速递推得到，其几何意义是对控制多边形进行一系列的中点割角过程．进而提出了利用割角多边形来逼近Bern—stein-Bézier多项式曲线的... 详细信息

基于Bézier曲线的控制多边形，介绍了割角多边形的概念．割角多边形的顶点可以由控制多边形的顶点快速递推得到，其几何意义是对控制多边形进行一系列的中点割角过程．进而提出了利用割角多边形来逼近Bern—stein-Bézier多项式曲线的新方法．当Bernstein-Bézier多项式曲线的次数为4～8时，分别导出了利用割角多边形逼近多项式曲线的精确界，此界值比利用控制多边形和拟控制多边形逼近Bernstein-Bézier多项式曲线所得的界值大为减小，极大地缩小了曲线的包围域，显著提高了逼近精度，节省了计算时间．

关键词：图形软件求交测试包围域 Bernstein—Bézier曲线割角多边形