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An effective thermal conductivity model for unsaturated compacted bentonites with consideration of bimodal shape of pore size distribution

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Science China(Technological Sciences) 2015年第2期58卷 369-380页

作者： chen yi feng WANG Min ZHOU Song HU Ran ZHOU Chuang Bing State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering (Ministry of Education) Wuhan University School of Civil Engineering and Architecture Nanchang University

An effective thermal conductivity model was proposed for unsaturated compacted bentonites with consideration of the bimodal shape of pore size distribution curves. The pores of soils were grouped into two dominant pore size modes corresponding to the intra- and inter-particle pores, and were simulated with randomly distributed spheroidal inclusions of different aspect ratios. With the assumption of preferential invasion of the wetting fluid （water） into pores of smaller sizes and by virtue of the analyt- ical solution to the inhomogeneous inclusion problem in heat conduction, the model was developed using the Mori-Tanaka （MT）, Ponte Castafieda-Willis （PCW） and self-consistent （SC） homogenization approaches for different considerations of the interactions between pores and the solid phase. The proposed model is functions of the thermal conductivities of the solid, liq- uid and gas phases, porosity, the degree of saturation, the aspect ratios of pores and/or soil particles, and the fraction of the smaller group of pores. The proposed model was validated against five sets of laboratory measurement data on the MX-80, FEBEX, KunigeI-V1 and GMZ01 bentonites, showing a good agreement between the model predictions and the laboratory measurements. The responses of the model with respect to the geometries of pores and solid particles were examined. Com- pared to series-parallel structural models, the proposed model may overall exhibit better performance if proper homogenization schemes are adopted, but as an advantage, the model has clearer physical mechanisms and a smaller number of parameters.

关键词： thermal conductivity homogenization schemes compacted bentonite unsaturated soil pore size distribution three-phase media

Valence electron structures dependences of structural stability and properties of REX_(3)(RE=rare earth;X=In,Tl)and RE(In,Co)3 alloys

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Chinese Physics B 2024年第11期33卷 331-339页

作者： Boyang Li Yongquan Guo yi-chen feng Xinze Wang Wei Liu School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China

Intermetallic compounds REIn3(RE=rare earth)have attracted much attention due to their unique characteristics:crystal field effect,Kondo effect,superconductivity,heavy fermion,and antiferromagnetism,and their cobalt diluted alloys exhibit the ferromagnetic half-metallic characteristics at room *** this study,an empirical electron theory(EET)is employed to investigate systemically the valence electronic structure,the thermal and magnetic properties of REX_(3) and their cobalt diluted alloys for revealing the mechanism of physical *** calculated bond length,melting point,and magnetic moment match the experimental ones very *** study reveals that structural stability and physical properties of REX_(3) and their cobalt dilute alloys are strongly related to their valence electron *** is suggested that the structural stability and cohesive energy depend upon the covalent electron,the melting point is modulated by covalent electron pair,and the magnetic moment is originated from 3d magnetic *** ferromagnetic characteristics of Co-diluted REIn3 alloys is originated from the introduction of strong ferromagnetic Co atom,but,a competition is caused between the electron transition from valence electron to magnetic electron on d orbit and its reversal electron transformation with increasing the content of cobalt,which results in the formations of diluted magnetic Gd(In,Co)3 alloy with minor amount of cobalt and strong magnetic Nd(In,Co)3 alloy with doping more Co atoms.

关键词： REX_(3) cobalt dilute alloy valence electron structures empirical electron theory moment

Amorphous and Crystallizable Thermoplastic Polyureas Synthesized through a One-pot Non-isocyanate Route

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Chinese Journal of Polymer Science 2019年第1期37卷 43-51,1-3页

作者： Jia-Long Ban Su-Qing Li chen-feng yi 赵京波 Zhi-Yuan Zhang Jun-ying Zhang Key Laboratory of Carbon Fiber and Functional Polymers (Beijing University of Chemical Technology) Ministry of Education College of Materials Science and Engineering Beijing University of Chemical Technology

A simple one-pot non-isocyanate route for synthesizing thermoplastic polyureas is presented. In situ urethanization was conducted from the ring-opening reaction of ethylene carbonate with poly(propylene glycol) bis(2-aminopropyl ether) and hexanediamine,m-xylylenediamine, or diethylene glycol bis(3-aminopropyl) ether at 100 °C for 6 h under normal pressure. Melt transurethane polycondensation was successively conducted at 170 °C under a reduced pressure of 399 Pa for different time periods. A series of nonisocyanate thermoplastic polyureas(NI-TPUreas) were prepared. The NI-TPUreas were characterized by gel permeation chromatography,FTIR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy,and tensile test. NI-TPUreas exhibited Mn of up to 1.67 × 104 g/mol, initial decomposition temperature over 290 °C, and tensile strength of up to 32 MPa. Several crystallizable NI-TPUreas exhibited Tm exceeding 98 °C. NI-TPUreas with good thermal and mechanical properties were prepared through a green and simple one-pot non-isocyanate route.

关键词： Non-isocyanate route Thermoplastic polyureas One-pot method Sustainable synthesis Transurethane polycondensation

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神威太湖之光上分子动力学模拟的性能优化

软件学报 2021年第9期32卷 2945-2962页

作者：田卓陈一峯北京大学信息科学与技术学院北京100871

“神威·太湖之光”国产超级计算机的特点是适用于高通量计算系统,此类系统往往存储器访问延迟,网络延迟较长.在实际应用中,有一大类问题是时间演化的模拟问题,往往需要高频状态迭代,每次迭代需要通信.此类应用问题的典型代表是分子动... 详细信息

“神威·太湖之光”国产超级计算机的特点是适用于高通量计算系统,此类系统往往存储器访问延迟,网络延迟较长.在实际应用中,有一大类问题是时间演化的模拟问题,往往需要高频状态迭代,每次迭代需要通信.此类应用问题的典型代表是分子动力学模拟,分子的性质依赖于时间演化,导致状态相关的时间尺度上难以并行化.实际应用中,全原子模型需要模拟超过μs时间尺度,每一步的物理时间为1fs-2.5fs,这意味着所需时间步个数超过1012个.众核处理器中,不同核心访存时需较长的“排队”等待,造成访存延迟.另外,网卡通信延迟以及较长的数据通路会带来网络延迟,由此导致在长延迟的众核处理器上进行一次有效的模拟几乎是不可能的.解决此类问题的主要挑战是提高迭代频率,即每秒执行尽可能多的迭代步.针对神威高性能芯片处理器的体系结构特点,以分子动力学模拟为例,研究了一系列优化策略以提高迭代频率:(1)单核通信与片上核间同步相结合,降低通信成本;(2)共享内存等待与从核同步相结合,优化异构体系结构中的核间同步;(3)改变计算模式,减少核间数据关联和依赖关系;(4)数据传输与计算重叠,掩盖访存延迟;(5)规则化问题,以提高访存凝聚性.

关键词：神威太湖之光分子动力学迭代异构同步

Endolymphatic sac papillary tumor： a case report

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Chinese Medical Journal 2011年第22期124卷 3828-3829页

作者： YU Shun-jiang chen yi-dong GAO feng QIU Xiao-guang CHANG Hong Department of Radiation Oncology Beijing Shijitan Hospital ＆ Peking University No. 9 Clinical College Beijing 100038 China

Endolymphatic sac papillary tumor （ELST） is an extremely rare and aggressive tumor characterized by hearing loss and temporal bone destruction. A case with clinical, imaging, pathologic and treatment data is reported and relevant literature is reviewed. A 25-year-old woman, with ELST underwent craniotomy for tumor subtotal resection, and the diagnosis was confirmed by pathologic examination. Postoperative radiotherapy consisted of 50.4 Gy/28 f was given accordingly. The patient is currently alive with no signs of tumor recurrence locally and no radiation side-effects observed after one year follow-up. Complete resection is impossible in most cases, local resection, adjuvant radiotherapy may provide favored local control. A long-term follow-up is highly advocated in consideration of its slow development course.

关键词： endolymphatic sac papillary tumor temporal bone surgery radiotherapy

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拉萨河鱼类调查及保护

水生生物学报 2010年第2期34卷 278-285页

作者：陈锋陈毅峰中国科学院水生生物研究所武汉430072 中国科学院研究生院北京100049

拉萨河是雅鲁藏布江最大的支流,其鱼类区系为隶属于裂腹鱼亚科、条鳅亚科和科的13种鱼类以及裂腹鱼属的一个自然杂交种。最近十几年,由于人类活动的影响,导致了大量的外来鱼类进入拉萨河水体。文章介绍了2004年至2006年对拉萨河鱼类进... 详细信息

拉萨河是雅鲁藏布江最大的支流,其鱼类区系为隶属于裂腹鱼亚科、条鳅亚科和科的13种鱼类以及裂腹鱼属的一个自然杂交种。最近十几年,由于人类活动的影响,导致了大量的外来鱼类进入拉萨河水体。文章介绍了2004年至2006年对拉萨河鱼类进行采样调查的情况。目前在拉萨河,鱼类组成包括以往记录的14种鱼类:拉萨裂腹鱼Schizothorax waltoni(Regan)、异齿裂腹鱼S.o'connori(Lloyd)、巨须裂腹鱼***(Regan)、双须叶须鱼Ptychobarbus dipogon(Regan)、尖裸鲤Oxygymnocypris stewartii(Lloyd)、拉萨裸裂尻鱼Schizopygopsis younghusbandi younghusbandi Regan、异齿裂腹鱼和拉萨裂腹鱼的一个自然杂交种、异尾高原鳅Triplophysa stewartii(Hora)、细尾高原鳅***(Herzenstein)、西藏高原鳅***(Regan)、东方高原鳅***(Herzenstein)、斯氏高原鳅***(Steindachner)、短尾高原鳅***(Herzenstein)、黑斑原Glyptosternum maculatum(Regan);8种外来鱼类:鲫Carassius auratus(Linnaeus)、麦穗鱼Pseudorasbora parva(Temminck et Schlegel)、泥鳅Misgurnus anguillicaudatus(Cantor)、黄黝鱼Hypseleotris swinhonis(Gunther)、鲤Cyprinus(C.)caupio Linnaeus、草鱼Ctenopharyngodon idellus(Cuvier et Valenciennes)、银鲫Carassius auratus gibelio(Bloch)、鲇Silurus asotus Linnaeus;2个未定种。调查结果表明拉萨河鱼类资源面临的两个主要问题是过度捕捞导致鱼类资源的减少和小型化以及外来鱼类入侵。文章针对这些情况作了分析和探讨,并对土著鱼类的保护与合理利用提出了一些建议:合理捕捞、严格禁渔期、控制外来鱼类、保护栖息地等。

关键词：拉萨河鱼类资源外来鱼类保护

排水通道分布式布设下双层地基平面应变固结分析

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工程力学 2020年第1期37卷 135-144页

作者：陈征张峰陈益峰胡少伟梅国雄武汉大学水资源与水电工程科学国家重点实验室湖北武汉430072 武汉大学水工岩石力学教育部重点实验室湖北武汉430072 中建海峡建设发展有限公司科技与设计管理部福建福州350015 南京水利科学研究院材料结构研究所江苏南京210024 广西大学土木建筑工程学院广西南宁530004

传统排水固结法处理地基过程中,通常采用全面布设水平排水通道来加速地基土固结。为经济且高效地利用水平排水通道,提出了条形分布式排水理念,变排水通道全面布设为分布布设。根据平面应变假设,建立了分布式排水边界下双层地基二维固结... 详细信息

传统排水固结法处理地基过程中,通常采用全面布设水平排水通道来加速地基土固结。为经济且高效地利用水平排水通道,提出了条形分布式排水理念,变排水通道全面布设为分布布设。根据平面应变假设,建立了分布式排水边界下双层地基二维固结模型,并通过边界转换法、积分变换法和局部离散法给出了相应的半解析解。在通过数值法验证了半解析解正确性的基础上,探讨了条形水平排水通道几何参数和地基土物理参数对分布式排水边界下地基固结效率的影响。研究表明:通过合理的选取排水通道几何参数既可以有效地降低过量排水通道造成的资源浪费,又可以在固结后期达到与全面布设排水通道几乎相同的固结效率;双层地基下层土体物理参数相较于上层土体对分布式排水通道下地基土固结效率的影响较小,工程设计中应优先考虑上层土体的物理力学性质来合理选择分布式排水通道的几何参数。

关键词：分布式排水通道双层地基平面应变固结边界转换法半解析解

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孔安国在汉代《尚书》学传播中地位和作用

北方论丛 2010年第1期 99-102页

作者：陈以凤山东大学历史文化学院山东济南250100

汉代《尚书》有今文和古文两个传授系统。孔安国为《尚书》博士,曾授业弟子倪宽,与西汉时期今文《尚书》学的兴盛有密切关系。同时他还整理、认读孔壁古文《尚书》,上献朝廷,并初步训解,传授弟子与后人,开创了古文《尚书》学派。故孔安... 详细信息

汉代《尚书》有今文和古文两个传授系统。孔安国为《尚书》博士,曾授业弟子倪宽,与西汉时期今文《尚书》学的兴盛有密切关系。同时他还整理、认读孔壁古文《尚书》,上献朝廷,并初步训解,传授弟子与后人,开创了古文《尚书》学派。故孔安国兼通今、古文《尚书》学,对两家之兴均有发起之功,为汉代《尚书》学的发展作出了重要的贡献。

关键词：孔安国今文《尚书》学古文《尚书》学

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现代旅游发展竞争元素分析

西北大学学报（自然科学版） 2012年第5期42卷 857-860页

作者：陈锋仪西安外国语大学旅游学院人文地理研究所陕西西安710061

目的提升旅游业的竞争质量。方法对现代旅游发展竞争元素运用提炼方法进行分析。结果现代旅游的竞争,已经从传统的企业之间的局部竞争转向政府、企业、社区居民全面介入的全面竞争。这种局面的出现来源于3个方面的原因,一是旅游业提升... 详细信息

目的提升旅游业的竞争质量。方法对现代旅游发展竞争元素运用提炼方法进行分析。结果现代旅游的竞争,已经从传统的企业之间的局部竞争转向政府、企业、社区居民全面介入的全面竞争。这种局面的出现来源于3个方面的原因,一是旅游业提升城市质量的功能深受政府的青睐,政府的角色扮演从幕后走向台前;二是旅游者的小众化以及个性化追求,迫使企业必须借助社会的力量才能够获得进步;三是由于不愿意看到自身利益受到侵害,并可以从中获得更大的利益,社区居民旅游投资人形象正在确立。结论参与者身份的变化,旅游业的竞争元素中势必出现新的元素,提炼出这些新的竞争元素,才能提升旅游业的竞争质量。

关键词：现代旅游竞争元素