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Journal of Materials Science & Technology 1995年第2期11卷 141-152页

作者： Mingshi SONG sizhu wu and xiuyun du(Research Institute of Polymeric Materials, Beijing University of Chemical Technology, Beijing, 100029, China) Beijing Univ of Chemical Technology Beijing China

An integral constitutive equation and a set of material functions for describing the strain history of polymer melts were formulated in terms of the Cauchy-Green and Finger tensors. A simple memory function and the dependence of ηo and τt on M3.4 were derived from the theory of non-linear viscoelasticity with constraints of entanglements for polymer melts and substituted into the Oldroye-Walters-Fredickson constitutive equation. An integral constitutive equation for polymer melts was consequently obtained. Some material functions of the constitutive equation related to certain 'test flow' are examined as follows : (1) simple steady shear flow; (2) steady elongation flow; (3) small-amplitude oscillatory shear flow; (4) stress growth upon the inception of steady shear elongation flow; (5) stress relaxation (modulus and compllance). These theoretical relations for simple steady shear flow were compared with experimental data from our laboratory and references for various polymer melts and concentrated solutions. A good agreement between the theory and experiment was achieved.

关键词： LDPE Material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Flow GR

Xiangshan Spirit Revisited and Emphasized

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China News Release 2024年第3期 60-62页

作者： wu xiuyun 不详

On March 25,1949,Mao Zedong(1893–1976)led the Central Committee of the Communist Party of China(CPC)to settle in Xiangshan,or Fragrant Hills,in the western suburb of Beiping(now Beijing).This made Xiangshan the headq... 详细信息

关键词： Hills sized Xiangshan

Highly selective growth of(6,5)single-walled carbon nanotubes from sigma phase alloy catalyst

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Nano Research 2024年第3期17卷 1999-2003页

作者： Liantao Xin Chen Ma Qianru wu Shaokang Liu Linhai Li xiuyun Zhang Liu Qian Maoshuai He Dong Li Fangqian Han Shulan Hao Lihu Feng Yahan Li Huaping Liu Lili Zhang Chang Liu Jin Zhang College of Chemistry and Molecular Engineering Qingdao University of Science and TechnologyQingdao 266042China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Physics Science and Technology Yangzhou UniversityYangzhou 225002China Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The chirality structure of a single-walled carbon nanotube(SWNT)strongly depends on the composition of catalyst used in the chemical vapor deposition *** this study,we develop a porous magnesia supported manganese-rhenium(MnRe/MgO)catalyst for chirality-selective synthesis of *** characterizations reveal that(6,5)tubes with a selectivity higher than 70%are grown from the Re-rich MnRe/MgO *** comparing the SWNT growth results with those of monometallic Mn or Re,the formation of sigma phase,an intermetallic compound occurring in transition-metal alloy systems,is revealed to be crucial for the dominant synthesis of(6,5)*** work not only extends the application of sigma phase alloy for catalytic synthesis of SWNTs,but also sheds lights on the growth of SWNTs with a high chirality selectivity.

关键词： single-walled carbon nanotubes sigma phase manganese-rhenium catalyst selective growth transition-metal alloy

Chronomodulated chemotherapy for locoregionally advanced nasopharyngeal carcinoma:A phase Ⅱ randomized controlled trial

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Radiation Medicine and Protection 2024年第1期5卷 43-48页

作者： Xiaoxiao Chen Feng Jin Weili wu Yuanyuan Li Jinhuan Long Xiuling Luo xiuyun Juan Li Pengxin Zhang Mang Zhang Department of Head and Neck Oncology Affiliated Cancer Hospital of Guizhou Medical UniversityGuiyang 550004China Departemnt of Oncology Affiliated Hospital of Guizhou Medical UniversityGuiyang 550001China

Objective:To validate the safety and efficacy of chronochemotherapy for locoregionally advanced nasopharyngeal carcinoma(NPC).Methods:Participants for this phase II randomized controlled trial were recruited from the Department of Head and Neck Oncology at the Affiliated Cancer Hospital of Guizhou Medical *** enrolled(128 in total,112 in the final analysis)between April 1,2017,and February 28,2018,were randomly divided into the chronochemotherapy and conventional chemotherapy *** the chronochemotherapy group,docetaxel was intravenously administered between 3:30 *** 4:30 *** day 1,followed by intravenous administration of cisplatin between 10:00 *** 10:00 *** day 1to day *** addition,5-fluorouracil was administered through a continuous intravenous pump between 10:00 *** 10:00 a.m.(2nd day)from day 1 to day *** the conventional chemotherapy group,docetaxel(on day 1),cisplatin(on day 2),and 5-fluorouracil(from day 1 to day 5,120 h in total)were administered without time-specific *** groups underwent intensitymodulated radiation therapy with 6-MV *** gross target volume(GTV)comprised the nasopharyngeal GTV and cervical lymph node *** primary endpoint was immune function,quantified by measuring dendritic cell and lymphocyte subsets,whereas the secondary endpoints were therapeutic efficacy and incidence of adverse *** Chi-square test was applied to compare total events between the groups,Mann-Whitney U test was used to compare the DC subsets and toxicities,and Wilcoxon signed-rank test was used to compare the continuous variables between the two ***:Chronochemotherapy preserved immune function,as evidenced by elevated levels of myeloid dendritic cells(P=0.394)and higher CD4/CD8 ratio(P?0.781).No significant difference in overall response rate,measured as the sum of complete and partial response rates,was observed between the groups(P=0.711).A reduction in the incidence of vomiting(P=

关键词： Nasopharyngeal carcinoma Chronochemotherapy Intensity-modulated radiotherapy Dendritic cells Adverse events Randomized controlled trial

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落叶松枯梢病在中国的适生性

生态学报 2024年第7期44卷 3027-3037页

作者：张秀芸伍文慧梁英梅北京林业大学省部共建森林培育与保护教育部重点实验室北京100083 北京林业大学博物馆北京100083

落叶松枯梢病(Neofusicoccum laricinum)是威胁落叶松人工林的检疫性林木病害。明确当前该病在中国的潜在适生区及其在未来对气候变化的响应,揭示影响该病害发生流行的主导环境变量,对落叶松枯梢病的早期预警及防治具有重要意义。基于... 详细信息

落叶松枯梢病(Neofusicoccum laricinum)是威胁落叶松人工林的检疫性林木病害。明确当前该病在中国的潜在适生区及其在未来对气候变化的响应,揭示影响该病害发生流行的主导环境变量,对落叶松枯梢病的早期预警及防治具有重要意义。基于落叶松枯梢病分布数据和环境数据,利用ENMTools、R和刀切法(Jack knife test)筛选分布点数据和环境因子,通过MaxEnt、ArcGIS、SDMTools等技术预测当前和未来气候条件下落叶松枯梢病在中国的潜在适生区,划分病害适生等级并计算各适生等级面积占比,绘制质心转移轨迹。结果表明:(1)建立的落叶松枯梢病在中国的潜在适生区预测模型具有高精确性和可信度(不同年份和不同气候模式下的AUC值均大于0.9);(2)影响落叶松枯梢病分布的主要环境变量为年平均气温、最暖季度降水量、年降水量和最暖季度平均温度;(3)当前气候模式下落叶松枯梢病在中国的潜在适生区面积占中国国土总面积的18.02%,中高适生区集中分布在中国辽宁东南部、吉林东部、黑龙江大部分地区、内蒙古东北部;(4)在三种不同气候条件下(ssp126、ssp245、ssp585),未来落叶松枯梢病在中国的潜在适生区面积与现代气候条件相比均有所减少,其质心由东北向华北、西南地区转移。落叶松枯梢病一旦发生将会造成不可逆的生态灾难和经济损失,因此本研究对落叶松枯梢病在中国的潜在适生区进行预测和分析,研究结果对合理区划落叶松枯梢病潜在入侵风险地、加强重点地区的检疫监测、及时制定有效的防治手段,以及对于发生区的监测和防治与未发生区的早期预警和监管具有重要意义。

关键词：落叶松枯梢病最大熵模型潜在适生区气候变化

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基于深度强化学习的老年肺癌发病风险预测研究

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中国数字医学 2024年第1期19卷 33-37页

作者：陈松景吴思竹中国医学科学院/北京协和医学院医学信息研究所北京100020

目的:采用深度强化学习方法构建老年肺癌发病风险预测模型,为有针对性地开展老年肺癌预防干预提供依据。方法:整合健康调查和基因突变数据,识别老年分层人群的肺癌发病危险因素,构建基于深度强化学习的老年肺癌发病风险预测模型。结果:6... 详细信息

目的:采用深度强化学习方法构建老年肺癌发病风险预测模型,为有针对性地开展老年肺癌预防干预提供依据。方法:整合健康调查和基因突变数据,识别老年分层人群的肺癌发病危险因素,构建基于深度强化学习的老年肺癌发病风险预测模型。结果:60岁以上男性和女性在戒烟超过5年后,肺癌发病风险都有显著下降,其中60岁以上男性携带C>A/G>T突变组肺癌发病率下降最明显,下降率为38.6%。结论:基于深度强化学习的老年肺癌发病风险预测研究可为老年肺癌预防干预和早诊早治提供理论支撑。

关键词：深度强化学习老年肺癌发病风险预测分析

影响地铁车辆段杂散电流分布及其对临近埋地钢质油气管道干扰的关键因素

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腐蚀与防护 2024年第5期45卷 73-81页

作者：吴广春于洋王修云赵芸黎安科工程技术研究院(北京)有限公司北京102200 国家管网集团联合管道有限责任公司西部分公司乌鲁木齐分公司乌鲁木齐830000 北京科技大学北京100083

为了系统性地明晰影响地铁车辆段杂散电流分布及其对临近埋地管道干扰的关键因素,选取国内某地铁车辆段及其临近的埋地管道为研究对象,采用GPS同步测量的方式监测三种工况下车辆段轨道、管道的电位和电流参数,对比分析了影响车辆段杂散... 详细信息

为了系统性地明晰影响地铁车辆段杂散电流分布及其对临近埋地管道干扰的关键因素,选取国内某地铁车辆段及其临近的埋地管道为研究对象,采用GPS同步测量的方式监测三种工况下车辆段轨道、管道的电位和电流参数,对比分析了影响车辆段杂散电流分布和管道干扰的主要因素,同时介绍了相应的代表性优化改进措施。结果表明:自动消弧装置反向导通、二极管支路和库内轨道接地方式是影响车辆段内杂散电流分布的三个主要因素,综合考虑三种因素才能实现对车辆段杂散电流干扰的有效缓解。

关键词：地铁车辆段杂散电流干扰关键因素埋地油气管道

Dynamics of Polymeric Fluids：Part Ⅱ The Molecular Theory of Die Swell： Correlation of Ultimate Die Swelling Effect to the Molecular Parameters and the Operational Variables

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Journal of Materials Science & Technology 2006年第5期22卷 664-676页

作者： Mingshi SONG Qiang XU Guixian HU sizhu wu Key Laboratory of Science and Technology of Controlled Chemical Reactions Beijing University of Chemical TechnologyBeijing 100029 China

A general expression for the correlation of the simple shear （tanφ） to the molecular parameters and the shear rate （·↑γ） was deduced. It shows that the simple shear （tanφ） may be resolved into free recoil （recoverable strain） and viscous heating （unrecoverable strain）. The magnitudes of the simple shears for recoil （tanφE） and （tanφv） for viscous heating not only depended on the molecular parameters and the operational variables, but also on the exponential fractions of the recoverable （1--↑W·↑γ） and unrecoverable （-↑W·↑γ） conformations for recoil and viscous heating. Therefore the magnitudes of the simple shears （tanφE） for recoil and （tanφv） for viscous heating are, respectively, expressed as the partition function to the （1--↑W·↑γ）th power and the partition function to the （-↑W·↑γ）th power. Thus correlations of the total recoil and the ultimately recoverable strains to the molecular parameters [n′, α, η0, GN^0 and （1--↑W·↑γ）] and the operational variables （·↑γ, （L/D） and tr） were deduced respectively, which show that at very different shear rates （0≤·↑γ≤∞） the polymeric liquids may exhibit a very different viscoelastic behaviors. After introducing the uniform two-dimensional extension, the definition of swelling ratio and the ratio of L to D [De=（L/D）], two expressions for the ultimate die swelling effect and the ultimate extrudate swelling ratio BEVT5 to the molecular parameters [n′, α, η0, GN^0 and （1--↑W·↑γ）] and the operational variables （·↑γ, （L/D） and tr） were obtained. The two correlation expressions were verified by the experimental data of high-density polyethylene （HDPE） which shows that the two correlation expressions can be used to predict the correlations of the ultimate extrudate swelling behaviors of polymeric liquids to the molecular parameters and the operational variables.

关键词： Die swell Viscoelastic recoil Entanglement

飞秒激光打印倾斜微结构在固液界面的变形研究(特邀)

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中国激光 2024年第12期51卷 422-430页

作者：祁乔乔李鑫凯胡海健陈超张晨初张亚超吴思竹劳召欣合肥工业大学仪器科学与光电工程学院测量理论与精密仪器安徽省重点实验室安徽合肥230009 合肥工业大学材料科学与工程学院材料物理及新能源材料与器件系安徽合肥230009 合肥工业大学机械工程学院安徽合肥230009

在微纳制造过程中,固液耦合界面的毛细力牵引行为可能会影响微结构的稳定性,导致结构变形或倒塌。本课题组基于飞秒激光双光子打印、显影后溶剂蒸发诱导毛细力牵引过程,对单个和双倾斜微板结构在毛细力下的变形行为进行研究。通过建立... 详细信息

在微纳制造过程中,固液耦合界面的毛细力牵引行为可能会影响微结构的稳定性,导致结构变形或倒塌。本课题组基于飞秒激光双光子打印、显影后溶剂蒸发诱导毛细力牵引过程,对单个和双倾斜微板结构在毛细力下的变形行为进行研究。通过建立固液耦合界面下倾斜微板的毛细力作用模型,综合研究了倾斜角度、微板高度和结构间距对毛细力牵引下微结构形态(内组装、倾斜和外倒塌)的影响。结果表明:固液耦合界面下结构在毛细力作用下的变形行为主要取决于结构所受毛细力(内、外毛细力)和自身支撑力之间的竞争关系。理论分析、实验结果和仿真模拟表明,在高纵横比倾斜微结构阵列中,可以通过邻近结构的耦合设计来避免不对称毛细力诱导下的微结构坍塌。本工作对涉及固液耦合情况的倾斜型、高纵横比微纳米结构的加工制造具有重要的参考意义。

关键词：飞秒激光双光子聚合倾斜微结构固液耦合界面毛细力

Dynamics of Polymeric Fluids 1. The Molecular Theory of Die Swell:A Set of Equation on Swelling Ratio in Extrudates

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Journal of Materials Science & Technology 2006年第1期22卷 93-107页

作者： Mingshi SONG Guixian HU Zhihong YANG Qiang xu sizhu wu Key Laboratory of Science and Technology of Controlled Chemical Reactions Beijing University of Chemical TechnologyBeijing 100029 China

The structural model of the multiple-transient networks and the mechanism of the multiple-reptation entangled chains due to the dynamic reorganization in the entangled sites were extensively applied on the die swell of polymeric liquids in the steady simple shear flow. The total （recoverable and unrecoverable） viscoelastic free energy of deformation and flow, the constitutive equation and the expression of the simple shear （tanψ） were deduced from the conformational probability distribution function of the entangled polymer chains. It found that：（1） the magnitudes of simple shear （tanψ） depended not only on the free recoil （or recoverable strain） but also on the viscous heating （or unrecoverable strain）; （2） the total recoil may be resolved into the instantaneous and delayed recoil. Based on these facts, the functions of the partition and two experiential fractions of the recoverable （1-Wγ） and the unrecoverable （Wγ） conformations for the recoil and viscous heating of polymeric liquids were defined correspondingly. Then the correlation of the instantaneously and ultimately （or total） recoverable strains to the （N1/T12）w and the fraction of trans-form conformation was obtained. After introducing the condition of uniform two-dimensional extension （αx=αy=α, αz=α^-2） and the swell ratio （B=α）, two sets of equations on the instantaneous and ultimate swelling ratios （BE, BEVT） were obtained, and a method to determine the fraction of the recoverable transform conformation were proposed, The equations of BE and BE5 were verified by the experimental data of HDPE （high denisity polyethylene） at two different high temperatures. It shows that the molecular theory of die swell can be used to predict the correlation of the swelling to the （NI/TI2）w and the fraction of trans-form conformation.

关键词： Die swell Entanglement Viscoelastic recoil