检索结果-南通市图书馆

Glass transition: from interaction potential changes to the corresponding structural and relaxation responses along the path of reaching the final equilibrium

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china chemistry 2018年第1期61卷 46-53页

作者： Guangcui Yuan charles c.Han center for Neutron research National Institute of Standards and Technology USA Department of Polymer Engineering The University of Akron Institute for Advanced Study Shenzhen University

Glass transition involves a many-body interaction and relaxation process. The split of relaxation spectrum and the extremely slow dynamics bring into considerations of non-linearity and non-equilibrium. Some of our recent findings in two measurable colloidal systems are reviewed, one with a simple attractive interparticle potential and the other with a competitive(repulsive vs. attractive)inter-particle interaction. With an approach from interaction potential changes to the corresponding structural and relaxation responses, along the path of reaching the final equilibrium, we illustrate some interesting physics in glass formation process. Also,some reviews on the popular glass transition theories are made to remind readers to avoid artifacts and misinterpretations.

关键词： glass transition slow dynamics polymer colloid

Molecular characterization and phylogenetic relationships of LMW-GS genes from c,N,U and Ss genomes among Aegilops species

在线全文

学校读者我要写书评

暂无评论

Molecular characterization and phylogenetic relationships of...

Hydrodynamics of the interceptor on a 2-D flat plate by cFD and experiments

中国作物学会50周年庆祝会暨2011年学术年会

作者： Shunli Wang~(1,2),Di chen ~(1,2),xixi Shen ~(1,2),Zitong Yu~1,Ting Zhang~1,Shanshan Jiang~1,Yueming Yan~(1,3) 1 Key Laboratory of Genetics and Biotechnology,college of Life Science,capital Normal University,100048 Beijing,china

In this work,9 novel LMW-GS genes(6 LMW-m and 3 LMW-i type) from 4 diploid and 1 tetraploid Aegilops species were amplified and cloned by allelic-specific *** of the deduced amino acid sequences showed that 7 and 2 LMW-GS had 9 and 7 cysteines,*** LMW-m type subunits genes had an extra cysteine at the c-terminalⅢ,which could form intermolecular disulphide bonds to extend

关键词： Aegilops species LMW-GS genes N-terminal domain conserved cysteines Phylogeny

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2015年第6期27卷 919-933页

作者： MANSOOrI M. FErNANDES A.c. Department of Naval and Ocean Engineering Federal University of Rio de Janeiro

Nowadays, the use of interceptor by both partial and total dynamic lift crafts is quite common. In this article, a lot of evidence is given regarding the effectiveness of interceptor. The interceptor, when placed at the stern region, changes the pressure distribution around the craft. Its presence affects drag force, lifting force and the position of pressure＇s center leading to a new trim. This study focuses on hydrodynamic effects of interceptors on a 2-D fiat plate based on both computational fluid dynamic （cFD） and experimental approaches. The reynolds average Navier-Stokes （rANS） equations are used to model the flow around a fixed flat plate with an interceptor at different heights and attack angles. Based on finite volume method and SIMPLE algorithm which uses static structures, this model can be analyzed and the rANS results can be compared with the experimental data obtained in the current channel of the laboratory of waves and current of cOPPE/UFrJ （LOc in Portuguese acronym）. According to the results, the increase of pressure at the end of the flat plate was proportional to the interceptor height. In addition, the existence of interceptors can significantly increase the lift force coefficient at high angles of attack also proportional to the interceptor height. The presence of interceptor at the end of the fiat plate increased both the lift coefficient and the drag coefficient but hydrodynamic drag did not grow as fast as the lift coefficient did. The lift coefficient increased much more. Furthermore, the results showed that the interceptor effectiveness is proportional to the boundary layer thickness at the end of the fiat plate. As the interceptor was inside the boundary layer alterations of flow speed led to changes in boundary layer thickness, directly affecting interceptor＇s efficiency. Optimum choice of interceptor height had a great effect on its efficiency, and in choosing it the flow speed and length of the boat must be taken into consideration.

关键词： interceptor craft 2-D fiat plate lifting coefficient reynolds average Navier-Stokes (rANS) pressure distribution,computational fluid dynamic drag

Blood pressure-related white matter microstructural disintegrity and associated cognitive function impairment in asymptomatic adults

在线全文

学校读者我要写书评

暂无评论

Stroke & Vascular Neurology 2023年第5期8卷 358-367页

作者： Julián N Acosta Stefan P Haider cyprien rivier Audrey c Leasure Kevin N Sheth Guido J Falcone Seyedmehdi Payabvash Department of Neurology Yale School of MedicineNew HavenConnecticutUSA Department of radiology and Biomedical Imaging Yale School of MedicineNew HavenConnecticutUSA Department of Otorhinolaryngology Ludwig Maximilians University MunichMunchenGermany

Background and objectives We aimed to investigate the white matter(WM)microstructural/cytostructural disintegrity patterns related to higher systolic blood pressure(SBP),and whether they mediate SBP effects on cognitive performance in middle-aged *** Using the UK Biobank study of community-dwelling volunteers aged 40-69 years,we included participants without a history of stroke,dementia,demyelinating disease or traumatic brain *** investigated the association of SBP with MrI diffusion metrics:fractional anisotropy(FA),mean diffusivity(MD),intracellular volume fraction(a measure of neurite density),isotropic(free)water volume fraction(ISOVF)and orientation dispersion across WM ***,we determined whether WM diffusion metrics mediated the effects of SBP on cognitive *** We analysed 31363 participants-mean age of 63.8 years(SD:7.7),and 16523(53%)*** SBP was associated with lower FA and neurite density,but higher MD and *** different WM tracts,diffusion metrics of the internal capsule anterior limb,external capsule,superior and posterior corona radiata were most affected by higher *** seven cognitive metrics,SBP levels were only associated with‘fluid intelligence’(adjusted praged FA of external capsule,internal capsule anterior limb and superior cerebellar peduncle mediated 13%,9%and 13%of SBP effects on fluid intelligence,while the averaged MD of external capsule,internal capsule anterior and posterior limbs,and superior corona radiata mediated 5%,7%,7%and 6%of SBP effects on fluid intelligence,*** Among asymptomatic adults,higher SBP is associated with pervasive WM microstructure disintegrity,partially due to reduced neuronal count,which appears to mediate SBP adverse effects on fluid *** metrics of select WM tracts,which are most reflective of SBP-related parenchymal damage and cognitive impairment,may serve as imaging biomarkers to

关键词： capsule Blood impairment

Numerical analysis of straight and curved underground pipeline performance after rehabilitation by cured-in-place method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2020年第1期5卷 30-42页

作者： K.J.Shou c.c.Huang Department of civil Engineering Chung Hsing University250Kuo Kuang RoadTaichungTaiwanRepublic of China Department of Civil EngineeringChung Hsing University250Kuo Kuang RoadTaichungTaiwanRepublic of China

Underground pipelines are prone to damage by corrosion in Taiwan due to the humid climate and the aging and overuse of ***-dig technologies are necessary,as the cities in Taiwan are highly *** methods,including the cured-in-place pipe(cIPP)method,provide an alternative to the new no-dig installation methods,which are comparatively more *** this study,the numerical analysis software ABAQUS was used to simulate straight-line and curved underground pipelines damaged by *** calibration by small-scale physical modeling in the laboratory,numerical models were applied to the analysis of the mechanical behavior of straight-line and curved underground *** analyze the performance of the cIPP rehabilitation method,different scenarios for straight-line and curved pipelines were *** included before-and after-rehabilitation,different internal pressures and surface loading conditions,and different liner deformabilities and pipe-liner interface *** results suggest that the cIPP method can reinforce damaged pipes by reducing stress concentration and differential displacement near the corrosion ***,proper liner thickness,liner material properties,and pipe-liner interface strength are essential for well-designed cIPP rehabilitation.

关键词： Straight-line pipeline curved pipeline No-Dig rehabilitation cured-in-place-pipe Soil-pipe interaction

W形六角铁氧体BaFe_(18)O_(27)电子结构与导电性的第一性原理研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

物理学报 2011年第10期60卷 542-548页

作者：李忠虎李林朱林东北大学理学院物理系沈阳110819 朝鲜理科大学物理系

采用基于第一性原理的GGA+U方法研究了BaFe18O27的晶体结构和基态电子结构.以实验数据为初始结构的离子弛豫显示,由于稳定结构中离子半径的差异和2d位Fe的存在,位于BaO层中6h位的O离子脱离了实验结构中原胞的"表面"位置,产生畸变.计算... 详细信息

采用基于第一性原理的GGA+U方法研究了BaFe18O27的晶体结构和基态电子结构.以实验数据为初始结构的离子弛豫显示,由于稳定结构中离子半径的差异和2d位Fe的存在,位于BaO层中6h位的O离子脱离了实验结构中原胞的"表面"位置,产生畸变.计算得到晶体磁矩为28μB/f.u.,与实验相符.电子态密度及能带计算表明该材料具有微弱的半金属特性,而且与c轴平行方向和垂直方向的能带色散关系有着很大不同,6g位Fe在该材料的输运特性中起着关键作用,它们形成一种"导电层",导致垂直电导率和平行电导率出现非常大的差异.

关键词：第一性原理 W形六角铁氧体电子结构导电性

在线全文

学校读者我要写书评

暂无评论

古生代末大变暖

Science Bulletin 2023年第21期68卷 2523-2526页

作者：宋海军 christopher r.Scotese State Key Laboratory of Biogeology and Environmental Geology School of Earth SciencesChina University of GeosciencesWuhan 430074China Department of Earth and Planetary Sciences Northwestern UniversityEvanston IL 60208USA

According to the recent global mean surface temperature curve[1],the temperature continued to rise over a period of 45 million years at the end of the *** global mean temperature increased from 11.7°c at 295 Ma at the beginning of the Permian to 32.7°c at 250 Ma at the beginning of the Triassic,a warming of21°c,one of the most dramatic warmings in the Phanerozoic(Fig.1a),which is referred to in this paper as the end-Paleozoic great warming(EPGW).Another significant warming event occurred in the mid-cretaceous,when the global average temperature rose by 8.8 c in 8 million years,reaching 28.2°c.

关键词： warming Paleozoic Permian

Dependence of flow strength and deformation mechanisms in common wrought and die cast magnesium alloys on orientation,strain rate and temperature

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2013年第4期1卷 275-282页

作者： S.xu W.r.Tyson r.Eagleson r.Zavadil Z.Liu P.-L.Mao c.-Y.Wang S.I.Hill A.A.Luo canmetMATErIALS Natural Resources Canada183 Longwood Road SouthHamiltonON L8P 0A1Canada School of Material Science and Engineering Shenyang University of Technology111 Shenliao West RoadShenyang 110870PR China University of Dayton research Institute 300 College ParkDaytonOH 45469-0133USA General Motors research&Development center WarrenMI 48090USA

The controlling plastic deformation mechanisms(*** or twinning)and the structural crash performance of Mg alloys are strongly influenced by loading mode,texture and *** paper summarizes the main results from an experimental program to assess these effects for commercial Mg alloy extrusions(AM30 and AZ31),sheet(AZ31),and high pressure die castings(HPDc,AM50 and AM60).Uniaxial tensile and compressive tests were performed over a wide range of strain rate and temperature(i.e.0.00075–2800 s^(−1) and 100℃ to−150℃)using conventional servo-hydraulic and high-strain-rate universal test machines and a split-Hopkinson-bar(SHB)*** primarily-slip-dominant deformation,the true stress–strain curves showed approximate power-law behavior,and the effects of strain rate and temperature on yield strength could be approximately described by constitutive equations linearly dependent on the rate parameter,Tln(5.3×10^(7)/ɛ˙)where T is test temperature in Kelvin andɛ˙is strain rate in s^(−1).In primarily-twin-dominant deformation,the effects of strain rate and temperature on yield and initial flow stress were negligible or small from quasi-static to 2800 s^(−1) owing to the athermal characteristics of mechanical twinning;the effects may become more pronounced with exhaustion of twinning and increasing proportion of slip.

关键词： constitutive equation Effects of strain rate and temperature Effects of orientation crashworthiness Magnesium alloy

The regulatory effects of SrEBP-1c on IrS-1 in L6 myotubes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The regulatory effects of SREBP-1c on IRS-1 in L6 myotubes