检索结果-南通市图书馆

Chinese Chemical Letters 1996年第4期7卷 385-386页

作者： Zhou X.Z. Xie w.H. Xu S.S. Department of Chemisty Nankai University Tianjin 300071

Me2GeGeMe2)[(η￣5-C_5H_4)Fe(CO)]_2(μ-CO)_2, 1 undergoes a novel reaction between its Ge-Ge and Fe-Fe bonds, forming a rearrangement product with a new cyclic structure,[Me_2Ge(η￣5- C_5H_4)Fe(CO)_2]_2, 2, which was...

关键词：

Effect of wall temperature modulation on the heat transfer characteristics of droplet-train flow inside a rectangular microchannel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第3期28卷 685-697页

作者： Vivekanand S.V.B.,raju V.r.K. Department of Mechanical Engineering National Institute of TechnologyWarangalTelangana 506004India

The numerical studies of water–oil two-phase slug flow inside a two-dimensional vertical microchannel subjected to modulated wall temperature boundary conditions have been discussed in the present *** researchers have contributed their efforts in exploring the characteristics of Taylor flows inside microchannel under constant wall heat flux or isothermal wall ***,there is no study available in the literature which discusses the impact of modulated thermal wall boundary conditions on the heat transfer behavior of slug flows inside ***,to bridge this gap,an effort has been made to understand the heat transfer characteristics of the flow under sinusoidal wall temperature ***,a single phase flow and heat transfer study was performed in microchannels,and the results of the fully developed velocity profile and heat transfer rate were validated with benchmark analytical *** an optimal selection of the combination of sinusoidal thermal wall boundary conditions has been made for the two-phase slug flow ***,the effects of amplitude(0 bεb 0.03)and frequency(0 bωb 750πrad·s-1)of the sinusoidal wall temperature profile on the heat transfer have been studied using the optimal combination of the wall boundary *** results of the numerical study using modulated temperature conditions on channel walls showed a significant improvement in the heat transfer over liquid-only flow by approximately 50%as well as over two-phase flow without wall temperature *** non-dimensional temperature contours obtained for different cases of temperature modulation clearly explain the root cause of such improvement in the heat ***,the results based on the hydrodynamics of the flow have also been reported in terms of variation of droplet shapes and film *** influence of Capillary number on the film thickness as well as heat transfer rates has also been *** addition,the measured fil

关键词： Heat transfer Microchannel Modulation Surface tension Taylor flow

PArTIAL FErrErS MATrICES

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 1994年第3期9卷 279-289页

作者： r．A．Brualdi 李乔 1. Department of Mathematics University of Wisconsin 53706 Madison Wisconsin U.S.A. 2. Department of Mathematics University of Science and Technology of China 230026 Hefei

we introduce a class of n×n matrices of 0's and l's which can be regarded as generalizations of the classical Ferrets boards of rook theory. Assuming the matrices are fully indecomposable, we determine the minimum permanent and the minimum numberof l's as a function of n. we also characterize these matrices in terms of weighted,top-rooted trees.

关键词： Ferrers board fully indecomposable matrix permanent.

Near-bed hydrodynamics associated with the entrainment of coarse particles at different protrusion heights

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2022年第6期34卷 1067-1080页

作者： Yushu Xie Bruce w.Melville Asaad Y.Shamseldin Colin N.whittaker Yifan Yang Department of Civil and Environmental Engineering The University of AucklandAucklandNew Zealand School of Engineering The University of WaikatoHamiltonNew Zealand

This paper presents an investigation of near-bed hydrodynamics for a protruding coarse particle over a regular roughened *** laboratory experiments were undertaken at the threshold flow condition,which induced dislodgement of the protruding *** different protrusion heights,the experimental results show that the protruding particle substantially changed the spatial distributions of time-averaged velocities,turbulent kinetic energy,and reynolds shear stress when compared with those obtained from a flat rough *** spatial distribution pattern of the flow characteristics shows a reasonable degree of similarity at different protrusion heights examined in this *** the target particle,a zone of low reynolds shear stress was *** analysis was conducted along the main flow direction,at an elevation close to the top of the target particle.A prevalence of sweep(Quadrant 4)and outwards interaction(Quadrant 1)events were associated with the dislodgement of the protruding *** findings imply that the drag force related to strong streamwise velocities may play a more significant role in protruding particle entrainment than the shear stress.

关键词： Entrainment particle protrusion flow structure shear stress quadrant analysis

Genetic-algorithm-based artificial intelligence control of a turbulent boundary layer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2021年第12期37卷 1739-1747页

作者： Jianing Yu Dewei Fan Bernd.r.Noack Yu Zhou Center for Turbulence Control Harbin Institute of Technology(Shenzhen)Shenzhen 518055China School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

An artificial intelligence(AI)open-loop control system is developed to manipulate a turbulent boundary layer(TBL)over a flat plate,with a view to reducing friction *** system comprises six synthetic jets,two wall-wire sensors,and genetic algorithm for the unsupervised learning of optimal control *** of the synthetic jets through rectangular streamwise slits can be independently controlled in terms of its exit velocity,frequency and actuation *** are conducted at a momentum-thickness-based reynolds number re_(θ)of *** local drag reduction downstream of the synthetic jets may reach 48%under conventional open-loop *** local drag reduction rises to 60%,with an extended effective drag reduction area,under the AI control that finds optimized non-uniform *** results point to the significant potential of AI in the control of a TBL given distributed actuation.

关键词： Turbulent boundary layer Active drag reduction Artificial intelligence

Laboratory Models for the Study of the Peri-implantation Period

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 1991年第1期4卷 48-55页

作者： STANLEY r.GLASSEr Department of Cell Biology and the Center for Population research and Studies in reproductive Biology Baylor College of Medicine Houston

The greatest risks to mammalian pregnancy occur during the peri-implantation period (passage through the uterotubal junction, blastulation, zona shedding, embryonic signaling and recognition, blastocyst attachment, postattachment events initiating placentation). Conventional markers and screening methods do not provide the means to clarify the relationship between exposure of a reproductively competent woman to a xenobiotic compound and the specific error in the functional expression of an embryogenetic process identified by impairment or deletion of that process. Laboratory models which provide the flexibility of in vitro culture methods and allow integration of cellular and molecular techniques have identified cell-specific, stage-specific markers that could focus on the mechanism of xenobiotic action. In vitro models have been used to define postattachment trophoblast cell differentiation. Trophoblast specific peptide hormones prove to be valid markers of established pregnancy. They provide no assessment of the risk to the embryo during the peri-implantation period. The relationship between developmental time of exposure and risk is discussed in terms of trophoblast differentiation.

关键词： Laboratory Models for the Study of the Peri-implantation Period

Transition States in Protein Folding

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2010年第2期7卷 283-300页

作者： Thomas r.weikl Max Planck Institute of Colloids and Interfaces Department of Theory and Bio-Systems14424 PotsdamGermany

The folding dynamics of small single-domain proteins is a current focus ofsimulations and experiments. Many of these proteins are ‘two-state folders’, i.e. pro-teins that fold rather directly from the denatured state to the native state, without pop-ulating metastable intermediate states. A central question is how to characterize theinstable, partially folded conformations of two-state proteins, in particular the rate-limiting transition-state conformations between the denatured and the native *** partially folded conformations are short-lived and cannot be observed directlyin experiments. However, experimental data from detailed mutational analyses of thefolding dynamics provide indirect access to transition states. The interpretation ofthese data, in particular the reconstruction of transition-state conformations, requiressimulation and modeling. The traditional interpretation of the mutational data aimsto reconstruct the degree of structure formation of individual residues in the transitionstate, while a novel interpretation aims at degrees of structure formation of cooperativesubstructures such as α-helices and β-hairpins. By splitting up mutation-induced freeenergies into secondary and tertiary structural components, the novel interpretationresolves some of the inconsistencies of the traditional interpretation.

关键词： Protein folding transition-state theory molecular dynamics mutational analysis

PrEDICTION OF THE MIXING ENTHALPIES OF BINArY LIQUID ALLOYS BY MOLECULAr INTErACTION VOLUME MODEL

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 336-340页

作者： H.w. Yang D.P. Tao Z.H. Zhou Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology Kunming 650093 China

The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model （MIVM）, which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted va... 详细信息

关键词： Molecular interaction volume model Mixing enthalpy Liquid alloys Prediction

Application of IITM-rANS3D to free-fall water entry of prismatic and non-prismatic finite wedges

在线全文

学校读者我要写书评

暂无评论

水动力学研究与进展B辑:英文版 2023年第3期35卷 417-430页

作者： Shaswat Saincher Kshitij Srivastava r.Vijayakumar V.Sriram Center for Maritime Experiments to Maritime Experience(ME2ME) Indian Institute of Technology MadrasChennaiIndia Department of Ocean Engineering Indian Institute of Technology MadrasChennaiIndia

High-speed watercraft and ships undergo coupled motions which make the front portion of the hull exit and violently re-enter *** induces short-term slamming loads that may compromise the structural integrity of the *** slamming of the bow can be modeled as straight wedges of different deadrise angles(DrAs)falling into water from different *** advent of computational fluid dynamics has allowed the problem of wedge-slamming to be simulated using the full Navier-Stokes equations thus complementing the pioneering studies based on ***,most researchers are opting to use commercial software to simulate the wedge-impact problem as it allows access to overset meshing algorithms which are robust in modeling the wedge as a moving *** boundary methods(EBMs)offer some advantages over overset meshing in that the mesh only needs to be generated once and Cartesian mesh-based solvers can be ***,the application of EBMs to wedge-impact has been limited in the literature and merits further *** this context,we investigate the applicability of the fast-fictitious-domain(FFD)based embedded boundary treatment to simulate the violent water-entry of *** extend our in-house Navier-Stokes model IITM-rANS3D to handle floating bodies through integration of a rigid-body dynamics solver and an algorithm to embed three-dimensional stereolithography(STL)geometries as solids over a Cartesian *** proposed algorithm is extensively benchmarked against variable DrA wedge-slamming experiments reported in the literature as well as constant DrA wedge-slamming experiments performed *** good agreement is reported in terms of the time-history of hydrodynamic impact pressures measured at various locations on the hull as well as the wedge motion responses thus demonstrating the suitability of FFD for simulating the coupled hydrodynamics of slamming for simplified hull geometries.

关键词： wedge water entry slamming fast-fictitious-domain IITM-rANS3D experiments

Fabrication of anatase titanium dioxide nanotubes by electroless deposition using polycarbonate for separate casting 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

Nano-Micro Letters 2010年第1期2卷 26-30页

作者： M.Boehme G.Fu E.Ionescu w.Ensinger Department of Materials Science Darmstadt University of Technology

Titanium dioxide nanotubes(TNTs)were prepared by electroless deposition using ion track etched polycarbonate *** ion tracks were prepared to the desired diameter of the TNTs outer *** dioxide nanotubes with a diameter of minimum 80 nm having a wall thickness of minimum 10 nm can be fabricated using this *** achieve nanotubes with thin walls and small surface roughness the tubes were generated by a several steps procedure under aqueous conditions at nearly room *** presented approach will process open end nanotubes with well defined outer diameter and wall *** this method TNT arrays up to 109 tubes per cm2having a tube length up to 30μm can be produced,single tubes are also *** structural properties of the grown TNTs were investigated by using various analytical techniques,*** electron microscopy(SEM),energy dispersive X-ray fluoresence spectrometer(EDX),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XrD),raman spectroscopy and Photoluminescence.

关键词： Electroless deposition Ion track template Nanotubes Titanium dioxide Anatase