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Perfect Matching in k-partite k-graphs and 3-uniform HM-bipartite Hypergraphs

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Acta Mathematicae Applicatae Sinica 2020年第3期36卷 636-641页

作者： Chun-qiu FAng Mei lu Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China

Let H=(V,E)be an n-balanced k-partite k-graph with partition classes V1,...,*** for every legal(k-1)-tuple f contained in V\V1 and for every legal(k-1)-tuple g contained in V\Vk such that f∪g■E(H),we have d(f)+d(g)≥n+*** this paper,we prove that under this condition H must have a perfect *** result of this paper is about the perfect matching in 3-uniform hm-bipartite *** G be a 3-uniform hm-bipartite hypergraph with one of whose sides V1 has the size n,the another side V2 has size 2 *** for all the legal 2-tuple f with|f∩V1|=1 and for all the legal 2-tuple g with|g∩V1|=0,we have d(f)≥n-2 and d(g)>n/2,then G has a perfect matching.

关键词： Perfect matching k-partite k-graph hm-bipartite hypergraph

Microstructures and mechanical properties of DZ125 directional solidified superalloy repaired by HIP technology

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Rare Metals 2023年第12期42卷 4264-4270页

作者： Si-Yu lu Zheng Zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China

DZ125 directional solidified superalloys show excellent bearing temperature ability and creep resistance and have been widely used to manufacture the advanced aviation engine blades ***,the high temperatures and stresses for longtime service would cause a loss of mechanical properties and service *** this paper,the damaged alloys were repaired using hot isostatic pressing combined with rejuvenation heat treatment technology,where the irregularγ'phases in damaged alloys are recovered to be cubic particles like original state and the creep cavities and casting porosities also reduce obviously compared with those in damaged *** restorable alloys exhibit apparently higher tensile properties and hardness than the alloys in damaged state,which is close or even more than those of original alloy,and their elongation and rupture life can satisfy criterion *** method can be easily extent to repair other damaged superalloys.

关键词： Directional solidified superalloy Hot isostatic pressing Microstructures Mechanical properties

Microstructure and Tribological Properties of In-situ Synthesized TiB_2- TiC /Ni Based Composite Coating by Laser Cladding

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材料热处理学报 2004年第05B期25卷 1000-1003页

作者： SUNRong-lu TAngYing YAngXian-jin LaserTechnologyInstituteofTianjinPolytechnicUniversity TianjinChina MaterialsScienceandEngineeringSchoolofTianjinUniversity TianjinChina LaserTechnologyInstituteofTianjinPolytechnicUniversity TianjinChina／／MaterialsScienceandEngineeringSchoolofTianjinUniversityTianjinChina

A TiB2 and TiC particles reinforced Ni based composites coating was prepared on TC4 alloy surface by chemical reaction among Ti, B and C elements using laser cladding technique. Microstructural analysis showed that the sizes of in-situ synthesized TiB2 and TiC particles ranged within 5~10um and l^2um, respectively, while both the two kinds of particles were uniformly distributed in the clad layer. The measurement of microhardness and wear and friction properties indicated that the microhardness of laser clad layer was HV900-1100, being three times of that of the TC4 alloy; the friction coefficient of the laser clad layer in air and in vacuum (10~5 Pa) ranged within 0.2-0.3 and 0.3-0.5, respectively; the wear rate in terms of mass loss was considerably lower than that of the TC4 alloy both in air and in vacuum environment.

关键词：激光包覆显微结构复合涂层磨损性能 TiB2-TiC/Ni

On the Estimation of Solutions for Some Linear Systems of Differential Equations

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Acta Mathematica Sinica,English Series 1998年第1期14卷 41-46页

作者： L. R. Awad E. M. El-Kholy sh. El-Bendary Universitat Hamburg Institut fur Angewandte Mathematik Bundesstraβe 55 20146 Hamburg Germany

In this paper we estimate the solutions of homogeneous linear system of differential equations with unbounded coefficients on the real line R. We also give a necessary and sufficient condition in order that the linear... 详细信息

关键词： Homogeneous linear Unbounded coefficient

On Li-Yau Heat Kernel Estimate

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Acta Mathematica Sinica,English Series 2021年第8期37卷 1205-1218页

作者： lu LI Zhen Lei ZHAng School of Mathematics Capital Normal UniversityBeijing 100048P.R.China

We present some improvements of the Li-Yau heat kernel estimate on a Riemannian manifold with Ricci curvature bounded *** a consequence we prove a gradient estimate to the heat kernel with an optimal leading term.

关键词： Heat kernel Li-Yau estimate gradient estimate

EXPERIMENTAL STUDY ON TURBULENT BOUNDARY LAYER CHARACTERISTICS OVER STREAMWISE RIBLETS

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Journal of Hydrodynamics 2004年第3期16卷 350-355页

作者： ZHAOZhi-yong DOngshou-ping DUYa-nan LaboratoryofFluidMeasurement UniversityofPetroleumBeijing102249China

Measurements of characteristics by means of a two-component Laser DopplerVelocimeter (LDV) were carried out in turbulent boundary layers over both a symmetric V-shapedribbed plate and a smooth one in a low speed wind tunnel. The present results clearly indicate thatthe logarithmic velocity profile over the riblets surface is shifted upward with a 30. 9% increasein the thickness of the viscous sublayer. Also a change in the log-law region is found. And themaximum value of streamwise velocity fluctuations is reduced by approximately 17%. The skewness andflatness factors do not show any change besides those in the region of y^+ shear stress over the riblets is reduced. Further more, in log-law region, theReynolds shear stress has a larger reduction of up to 18%.

关键词： laser doppler velocimeter (LDV) stream-wise riblets turbulent boundarylayer turbulence fluctuations characteristics

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某市医疗机构丙泊酚临床使用与管理现状分析

中国新药与临床杂志 2025年第1期44卷 13-17页

作者：侯立丽朱亚捷周益众彭楠卢泽昌邵蓉上海市卫生健康委员会监督所中国药科大学国际医药商学院中国药科大学国家药物政策与医药产业经济研究中心

目的分析某市医疗机构丙泊酚临床使用与管理现状，为规范丙泊酚的临床使用管理提供合理建议。方法通过文献回顾和专家咨询，开展问卷调查，收集166家医疗机构的丙泊酚使用和管理现状，并对医疗机构建立丙泊酚管理制度与其丙泊酚管理... 详细信息

目的分析某市医疗机构丙泊酚临床使用与管理现状，为规范丙泊酚的临床使用管理提供合理建议。方法通过文献回顾和专家咨询，开展问卷调查，收集166家医疗机构的丙泊酚使用和管理现状，并对医疗机构建立丙泊酚管理制度与其丙泊酚管理现状间的相关性进行Fisher精确检验。结果丙泊酚临床使用和管理过程中最主要的风险是缺乏针对丙泊酚的管理制度，医疗机构建立丙泊酚管理制度与其高警示标识管理、储存设备加锁、建立使用记录单、余液处理、丙泊酚使用管理培训、定期抽查等管理现状方面存在显著差异（P<0.01）。结论缺乏针对性的管理制度是医疗机构在临床使用和管理丙泊酚过程中面临的最大挑战。应制定并实施统一的丙泊酚管理制度，进一步对包括用药记录、药品回收、处方/调剂权限、追溯系统在内的高风险环节实施强化管理。

关键词：丙泊酚临床使用医疗机构医疗监管

Factors influencing utilization and satisfaction with external breast prosthesis in patients with mastectomy:A systematic review

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International Journal of Nursing Sciences 2015年第2期2卷 218-224页

作者： Ya-nan Liang Bo Xu Cancer Hospital Chinese Academy of Medical Sciences Beijing 100021China

Purpose:The aim of this study is to describe and analyse the factors which influence utilization of EBPs among breast cancer patients worldwide and particularly in ***:Literature searches were conducted in Wanfang,CNKI,and PubMed databses in order to identify relevant articles published in both Chinese and English up to October *** phrase“external breast prosthesis”in Chinese was used to search titles,abstracts,and key words to find articles in Wanfang and CNKI electronic *** and related terms for external breast prosthesis were combined and used for searches performed in *** references were subsequently extracted from the bibliographies of all included articles and *** analysis was applied in this study rather than ***:The number of relevant studies published in other countries is five times greater than the literature published in China,with most articles written by Australian *** on the existing references,reconstruction,comfort,appearance,cost,mental status,and supportive information were the main factors influencing choice of treatment options by ***:Six main factors influencing EBP use worldwide were *** the number of breast cancer cases per year is increasing at a much higher rate in China relative to the average number globally,relevant studies on Chinese patients are ***,further studies should be undertaken in China in order to develop effective service modalities in order to improve quality of life of patients.

关键词： External prosthesis Utilization Satisfaction Systematic review

消费周期的持久性研究——基于城镇居民消费结构的视角

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湘潭大学学报（哲学社会科学版） 2012年第3期36卷 69-75页

作者：鲁旭赵楠中国人民大学经济学院北京100872

以Hansen(1999)提出的Grid-Bootstrap技术为基础,通过构造统计无偏的中值估计量(Median UnbiasedEstimator)对我国城镇居民消费周期的持久性进行实证研究,结果表明:第一,八大类消费周期之间或是各消费周期与总消费周期相比,均呈现出迥... 详细信息

以Hansen(1999)提出的Grid-Bootstrap技术为基础,通过构造统计无偏的中值估计量(Median UnbiasedEstimator)对我国城镇居民消费周期的持久性进行实证研究,结果表明:第一,八大类消费周期之间或是各消费周期与总消费周期相比,均呈现出迥异的持久性特征。第二,将各类消费周期持久性按顺序排列,排序结果与西方研究中关于耐用品消费持久性较低、非耐用品消费持久性较高这一结论存在一定差距。第三,与西方国家相比,我国各类消费周期的持久性普遍偏低。上述结论不仅丰富了消费周期的典型特征,还可为相关当局制定拉动内需政策提供参考依据。

关键词：消费周期持久性 Grid-Bootstrap技术