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高斯与平顶光束纳秒脉冲激光物质蒸发烧蚀动力学仿真研究

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物理学报 2024年第9期73卷 186-198页

作者：尹培琪许博坪刘颖华王屹山赵卫汤洁中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室西安710119 中国科学院大学北京100049

基于建立的纳秒脉冲激光与金属铝相互作用的二维轴对称模型,仿真研究了光束整形对纳秒脉冲激光烧蚀金属铝过程中蒸发烧蚀动力学的影响.结果表明:等离子体屏蔽对靶材的烧蚀特性具有显著影响,屏蔽效应主要体现在脉冲的中后期.对于3种激光... 详细信息

基于建立的纳秒脉冲激光与金属铝相互作用的二维轴对称模型,仿真研究了光束整形对纳秒脉冲激光烧蚀金属铝过程中蒸发烧蚀动力学的影响.结果表明:等离子体屏蔽对靶材的烧蚀特性具有显著影响,屏蔽效应主要体现在脉冲的中后期.对于3种激光轮廓,高斯光束的屏蔽效果最强,随着整形后的平顶光束直径的增大,屏蔽效果逐渐减弱.平顶光束与高斯光束作用下,靶材温度的二维空间分布较为不同.高斯光束作用时,靶材中心最先升温,随后温度沿径向和轴向扩散.由于平顶光束的能量分布更加均匀,因此一定径向范围内的靶材同时升温.光束整形对靶材的蒸发烧蚀动力学影响较大.对于高斯光束,靶材中心先烧蚀,随后产生径向烧蚀.由于整形后平顶光束的能量密度降低,因此靶面蒸发时间较高斯光束延后,并且一定径向范围内的靶材同时发生蒸发烧蚀.3种激光轮廓下,靶材的蒸发烧蚀形貌与光束的强度分布类似,其中高斯光束的烧蚀坑呈中间深两边浅的特点,平顶光束的烧蚀坑较为平坦.

关键词：光束整形激光与物质作用蒸发烧蚀等离子体屏蔽

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大气压氦气预电离直流辉光放电二维仿真研究

物理学报 2024年第1期73卷 227-240页

作者：刘在浩刘颖华许博坪尹培琪李静王屹山赵卫段忆翔汤洁中国科学院西安光学精密机械研究所瞬态光学与光子技术重点实验室西安710119 中国科学院大学北京100049 淮阴工学院数理学院淮安223003 四川大学机械工程学院分析仪器研究中心成都610064

基于二维流体模型,研究了大气压下预电离对短间隙和长间隙直流辉光放电的影响.对于两种放电,随着预电离的增强,带电粒子分布沿着放电方向逐渐向阴极偏移,使得阴极位降区不断收缩.从垂直放电方向来看,正柱区、负辉区和阴极位降区的宽度... 详细信息

基于二维流体模型,研究了大气压下预电离对短间隙和长间隙直流辉光放电的影响.对于两种放电,随着预电离的增强,带电粒子分布沿着放电方向逐渐向阴极偏移,使得阴极位降区不断收缩.从垂直放电方向来看,正柱区、负辉区和阴极位降区的宽度都不断增大,电子、离子密度的分布更加均匀.对于电场而言,随着预电离的增强,阴极位降区电场的纵向分量分布逐渐向阴极收缩,阴极附近的电场整体降低且分布更加均匀.电场的纵向分量分布逐渐减小,同时电场区域逐渐向壁面收缩.维持电压和放电功率都明显地降低.此外,随预电离的增加,短间隙放电中的压降始终集中在阴极位降区,而在长间隙放电中的压降由阴极位降区逐渐转移至正柱区.仿真结果表明,预电离能够有效增强放电均匀性,并降低放电维持电压和能量消耗.该工作对进一步优化电极配置和等离子体源的运行参数具有重要指导意义.

关键词：预电离流体模型直流辉光放电

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Immunologic mechanisms and treatment of acute coronary syndromes

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Chinese Medical Journal 2006年第24期119卷 2108-2113页

作者： liu ying LIAO Yu-hua CHENG Xiang Institute of Cardiology Union Hospital Tongji Medical College of Huazhong University of Sciences ＆ Technology Wuhan 430022 China

Acute coronary syndromes （ACS） consist of unstable angina pectoris, non-ST segment elevation myocardial infarction and ST segment elevation myocardial infarction. The pathogenic mechanism of ACS is most often based on thrombosis secondary to plaque rupture in atherosclerosis （AS）. Recent studies indicate that immune and inflammatory responses are associated with the plaque instability in AS.1 Here we review molecular and cellular immunologic processes linked to initiation and progression of ACS and discuss potential applications of immunosuppressant therapy and the possible beneficial immune effects of some cardiovascular medicines used commonly in ACS.

关键词： acute coronary syndrome immunity stents glucocorticosteroids rapamycin

Re-reddening on Strip Surface After Water Cooling

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Journal of Iron and Steel Research International 2007年第3期14卷 26-29,55页

作者： ZHI ying liu Xiang-hua WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

After water cooling, there is a big temperature difference between the center and the surface of strip, which leads to the heat transfer from the center to the surface, and the surface temperature can rise in a short time. The finite element method was used to simulate the phenomena of re-reddening on the surface of strip and to analyze the temperature field of hot roiled strip during laminar cooling, and the periodical variation curve of the cooling rate was obtained during water cooling and subsequent re-reddening. The results show that the critical line of the cooling rate is at 1/3 of the half-thickness from the strip surface. The regression model of the relation of rereddening temperature, time, and distance from the surface was obtained in the re-reddening region. Re-reddening regularity on the surface of strip under the condition of different thickness and cooling rate was also studied.

关键词： temperature field re-reddening laminar cooling cooling rate hot rolled strip finite element method

Morphological stability analysis of vesicles with mechanical-electrical coupling effects

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Acta Mechanica Sinica 2010年第1期26卷 5-11页

作者： Lingtian Gao ying liu ~ Qing hua Qin Xi Qiao Feng Applied Mechanics Lab Department of Engineering Mechanics Tsinghua University 100084 Beijing China Institute of Mechanics Beijing Jiaotong University 100044 Beijing China Department of Engineering The Australian National UniversityCanberra ACT 0200 Australia

Using a recently established liquid crystal model for vesicles, we present a theoretical method to analyze the morphological stability of liquid crystal vesicles in an electric field. The coupled mechanical-electrical effects associated with elastic bending, osmotic pressure, surface tension, Max- well pressure, as well as flexoelectric and dielectric proper- ties of the membrane are taken into account. The first and second variations of the free energy are derived in a com- pact form by virtue of the surface variational principle. The former leads to the shape equation of a vesicle embedded in an electric field, and the latter allows us to examine the stabil- ity of a given vesicle morphology. As an illustrative exam- ple, we analyze the stability of a spherical vesicle under a uniform electric field. This study is helpful for understanding and revealing the morphological evolution mechanisms of vesicles in electric fields and some associated phenomena of cells.

关键词： Vesicle Cell membrane - Stability Mechanical-electrical coupling

Analysis of Essential Oils from Flower-buds, Leaves and Stems of Filipendula palmata(Pall.) Maxim.

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Chemical Research in Chinese Universities 2005年第6期21卷 658-662页

作者： WU Yin MENG Xiang-ying liu Xiao-hua BAO Yong-li WANG Shu-ping LI Yu-xin Institute of Genetics and Cytology Northeast Normal University Changchun 130024 P. R. China

The essential oils of the flower-buds, leaves and stems of Filipendula palmata（ Pall. ） Maxim. were analyzed by GC and GC-MS. Thirty-three, forty-seven and forty-seven compounds in the flower-buds, leaves and stems were identified, respectively. Methyl salicylate exists in a great amount which is up to 70. 10% in the flower-buds. Its amount is also high in other two parts. The data obtained show that it may be one of the main natural mosquito-expelling and pain-alleviating components in the three parts. The flower-buds are the main active part with the mosquito-expelling function.

关键词： Filipendula palmata( Pall. ) Maxim. Essential oil GC-MS

Hydrochemical Characteristics and Evolution of Underground Brine in Lop Nur,Northwestern China

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 786-800页

作者： BO ying liu Chenglin JIAO Pengcheng LU Fenglin ZHANG hua MNR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

Lop Nur is located at the eastmost end of the Tarim Basin in Xinjiang,Northwestern *** study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur,based on analytical data from 429 water samples(mainly brine).It is found that in the NE-SW direction,from the periphery to the Luobei sub-depression,while the hydrochemical type varies from the sodium sulfate subtype(S)to the magnesium sulfate subtype(M),the corresponding brine in the phase diagram transfers from the thenardite phase(Then)area,through the bloedite phase(Blo),epsomite phase(Eps),picromerite phase(Picro),finally reaching the sylvite phase(Syl)*** for the degree of evolution,the sequence is the peripheryying glauberite brineying clastic brine *** is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude,as well as the changes in local water circulation in recent *** and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic *** strontium isotopic composition indicates that the Lop Nur brine primarily originates from surface water;however,deep recharge may also be involved in the evolution of the brine,according to previous noble gas *** is confirmed that the brine in Lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's *** on chemical compositions of brine from drillhole LDK01 and previous lithological studies,the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration-dilution periods.

关键词： brine evolution isotope enrichment potassium Lop Nur

Caprylic Acid Improves Lipid Metabolism, Suppresses the Inflammatory Response and Activates the ABCA1/p-JAK2/pSTAT3 Signaling Pathway in C57BL/6J Mice and RAW264.7 Cells

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Biomedical and Environmental Sciences 2022年第2期35卷 95-106页

作者： ZHANG Xin Sheng ZHANG Peng liu ying hua XU Qing ZHANG Yong LI Hui Zi liu Lu liu Yu Meng YANG Xue Yan XUE Chang Yong Department of Nutrition the First Medical Center of PLA General HospitalBeijing 100853China Guizhou Crops of Chinese Armed Police Force Guiyang 550001GuizhouChina Department of Nutrition PLA Rocket Force Characteristic Medical CenterBeijing 100088China

Objective This study aimed to investigate the effects of caprylic acid(C8:0)on lipid metabolism and inflammation,and examine the mechanisms underlying these effects in mice and *** Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a highfat diet(HFD)without or with 2%C8:0,palmitic acid(C16:0)or eicosapentaenoic acid(EPA).RAW246.7 cells were randomly divided into five groups:normal,lipopolysaccharide(LPS),LPS+C8:0,LPS+EPA and LPS+*** serum lipid profiles,inflammatory biomolecules,and ABCA1 and JAK2/STAT3 mRNA and protein expression were *** C8:0 decreased TC and LDL-C,and increased the HDL-C/LDL-C ratio after injection of *** LPS,it decreased TC in mice(P<0.05).Moreover,C8:0 decreased the inflammatory response after LPS treatment in both mice and cells(P<0.05).Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD,C16:0 and EPA,and resulted in lower TNF-α,NF-κB mRNA expression than that with HFD(P<0.05).In RAW 264.7 cells,C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group,and higher protein expression of ABCA1,p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups(P<0.05).Conclusion Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response,and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.

关键词： Caprylic acid Inflammatory cytokine ATP binding cassette transporter A1 Janus kinase 2 Signal transducer and activator of transcription 3

Solidification crack characteristics and sensitivity of peritectic steel

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Journal of Iron and Steel Research International 2024年第7期31卷 1668-1679页

作者： Ya-qiang Li Jian-hua liu Zi-ming Wang ying-ying Li Yang He Xiao-wei Li Department of Automotive Engineering Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Hebei Special Vehicle Modification Technology Innovation Center Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Institute of Engineering Technology University of Science and Technology BeijingBeijing 100083China School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhou 213164JiangsuChina

The characteristics and sensitivity of solidification cracks in peritectic steels were investigated using directional solidifi-cation *** cracks were observed in both hypoperitectic steels(12CrlMoV,15CrMo)and hyper-peritectic steel(20CrMo)during solidification at growth velocities of 15,50,and 80 pm/*** the dendritic boundaries,sulphide precipitates were found,promoting crack *** on the statistical analysis of interdendritic cracks in peritectic steels,the area ratio(RA)of interdendritic cracks in a directional solidification structure was proposed to evaluate the crack sensitivity of peritectic ***,the crack sensitivities of peritectic steels(12CrlMoV,15CrMo,and 20CrMo)were tested,evaluated,and compared with the surface crack rates of three types of steels produced from a steel *** results demonstrated that RA was in good agreement with that of the steel plant,and the crack sensitivity of 12CrlMoV steel was the strongest,followed by that of 15CrMo and 20CrMo ***,RA can be used to evaluate the crack sensitivity of peritectic steel.

关键词： Peritectic steel-Directional solidification Growth velocity Dendritic structure Solidification crack Crack sensitivity