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Chinese Journal of.Chemistry 2012年第1期30卷 109-114页

作者： f.thalla Magda f. Chemistry Department Faculty of ScienceAlexandria UniversityP.O.426 IbrahimiaAlexandria 21321Egypt

Kinetics of.the reaction of.2-chloro-3,5-dinitrobenzotrif.ouride with aniline were studied in toluene, metha- nol-toluene binary solvents, benzene and chlorof.rm. The reaction in toluene exhibits third-order kinetics consistent with aggregates of.aniline. Thermodynamic parameters AH#, AS# and AG# are calculated and discussed f.r the reaction of.2-chloro-3,5-dinitrobenzotrif.ouride with aniline in methanol-toluene. Molecular complexes between aniline and the substrate are rejected spectrophotometricaly. The mechanism is studied and compared with the reac- tion in presence of.pyridine. It shows an amine dependence and f.rmation of.homo and/or hetero mixed aggregates between aniline and pyridine i.e. dimer mechanism.

关键词： kinetics 2-chloro-3,5-dinitrobenzotrif.ouride methanol-toluene

Multiscale stochastic f.nite element method on random f.eld modeling of.geotechnical problems- a f.st computing procedure

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f.ontiers of.Structural and Civil Engineering 2015年第2期9卷 107-113页

作者： Xi f. XU School of.Civil Engineering Beo'ing Jiaotong University Beijing 100044 China

The Green-f.nction-based multiscale stochastic f.nite element method (MSf.M) has been f.rmulated based on the stochastic variational principle. In this study a f.st computing procedure based on the MSf.M is developed to solve random f.eld geotechnical problems with a typical coef.icient of.variance less than 1. A unique f.st computing advantage of.the procedure enables computation perf.rmed only on those locations of.interest, theref.re saving a lot of.computation. The numerical example on soil settlement shows that the procedure achieves signif.cant computing ef.iciency compared with Monte Carlo method.

关键词： multiscale f.nite element settlement perturbation random f.eld geotechnical

Early stages of.non-classic crystal growth

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Science China Chemistry 2011年第12期54卷 1867-1876页

作者： GREER Heather f. EaStChem School of ChemistryUniversity of St Andrews

Investigation of.early stages of.crystal growth revealed that crystal growth in some systems may not f.llow the classic *** the early stages of.inorganic crystal growth,precursor molecules and/or nanocrystallites may aggregate into large and disordered particles with the assistance of.some polymers or *** crystallization of.these aggregates would then take place to f.rm shells with high crystallinity and density,f.llowed by an extension of.the crystallization f.om surf.ce to *** so-called reversed crystal growth mechanism has been f.und in crystallization of.several inorganic compounds including zeolites,perovskites,metals and metal oxides,and will be identif.ed in more material *** establishment of.this new crystal growth route gave us more f.eedom to control the morphology of.crystals and to understand the f.rmation mechanism of.many natural *** article gives a brief.review of.the recent research in this f.eld by f.aturing some typical examples of.the reversed crystal growth.

关键词： reversed crystal growth hollow crystals core-shell particles electron microscopy

f.rtif.cation Challenges and Needs

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Biomedical and Environmental Sciences 2001年第1期14卷 98-103页

作者： RODOLf. f. f.ORENTINO President Philippine Association of Nutrition Philippines

Experience in many parts of.the developing world has shown that f.od f.rtif.cation of.ers a cost_ef.ective and sustainable solution to the problem of.micronutrient malnutrition. Building on the advances in science and technology and backed by studies on the economic benef.ts of.f.rtif.cation programs, governments and industry are beginning to respond positively to the call of.nutrition advocates to adopt f.rtif.cation as a long_term strategy. On the other hand, f.rmidable challenges still remain in many countries in Asia, constraining the widespread adoption of.this strategy. The science and technology community needs to provide adequate scientif.c and technological inf.rmation as basis f.r planning and decision making. The government f.ces the challenge of.providing the enabling environment f.r all stakeholders to cooperate in the f.rtif.cation ef.ort. Industry f.ces the challenge of.adapting its production system to the requirements of.f.rtif.cation in order that they can contribute to social objectives while pursuing their economic objectives. The international and bilateral aid agencies need to seek tried and innovative ways to support the multiple players of.f.od f.rtif.cation, as these players in turn f.ce the challenges that conf.ont them.

关键词： Developing Countries f.od Industry f.od f.rtif.ed Asia f.od Technology Humans Nutrition Disorders Public Health

Precise correction to parameter ρ in the littlest Higgs model

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Chinese Physics C 2008年第2期32卷 100-103页

作者： f.rshid Tabbakh f. f.rnoudi School of.Nuclear Science Institute of Nuclear Science and Technology Atomic Energy Organization of Iran Northern Kargar Av. Tehran Iran

In this paper tree-level violation of.weak isospin parameter, ρ in the f.ame of.the littlest Higgs model is studied. The potentially large deviation f.om the standard model prediction f.r the ρ in terms of.the littlest Higgs model parameters is calculated. The maximum value f.r ρ f.r f.=1 TeV, c = 0.05, c＇ = 0.05 and v＇ = 1.5 GeV is ρ = 1.2973 which means a large enhancement than the SM.

关键词： the littlest Higgs model custodial symmetry violation

High Strain Rate Superplasticity in a Micro-grained Al-Mg-Sc Alloy with Predominant High Angle Grain Boundaries

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Journal of.Materials Science & Technology 2012年第11期28卷 1025-1030页

作者： f. C. Liu Z.Y. Ma f. C. Zhang Shenyang National Laboratory f.r Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China State Key Laboratory of.Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004China

f.iction stir processing （f.P） was applied to extruded AI-Mg-Sc alloy to produce f.ne-grained microstructure with a grain size of.2.2μm. Electron backscatter dif.raction （EBSD） result showed that the grain boundary misorientation distribution was very close to a random grain assembly f.r randomly oriented cubes. Super- plastic investigations in the temperature range of.425-500 ℃ and strain rate range of.1x100^-2-1x10 s^-1 showed that a maximum elongation of.1500% was achieved at 475 ℃ and a high strain rate of.1x100^-2-1x10 s^-1. The f.P AI-Mg-Sc exhibited enhanced superplastic def.rmation kinetics compared to that predicted by the constitutive relationship f.r superplasticity in f.ne-grained aluminum alloys. The origin f.r enhanced superplas- tic def.rmation kinetics in the f.P alloy can be attributed to its high f.action of.high angle grain boundaries （HAGBs）. The analyses of.the superplastic data and scanning electron microscopy （SEM） examinations on the surf.ces of.def.rmed specimens indicated that grain boundary sliding is the main superplastic def.rmation mechanism f.r the f.P AI-Mg-Sc alloy.

关键词： Superplasticity f.iction stir processing Aluminum Microstructure f.iction stir welding

Topsoil as Af.ected by Dung Deposition Under Resting Places of.Red Howler Monkey (Alouatta seniculus)

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Pedosphere 2008年第6期18卷 691-698页

作者： S. POUVELLE f. f.ER J. f. PONGE Musum National d'Histoire Naturelle CNRS UMR 7179 4 avenue du Petit-Chateau

The short-term inf.uence of.dung deposition and the f.rther redistribution of.dung by dung beetles were studied under a resting place of.the red howler monkey （Alouatta seniculus） living in tropical ralnf.rests of.South America. Monkey dung was experimentally clumped on the f.eld in a place used by troops of.howler monkeys f.r resting in the Nouragues Reserve Station, f.ench Guiana. Dung-treated plots were sampled serially over three weeks and compared with controls located in their immediate vicinity. The composition of.the soil matrix （top 10 cm） was studied in successive microlayers using an optical method. Under the inf.uence of.dung beetle activity, the topsoil became more homogeneous by losing its litter, its content in earthworm f.eces increased in the course of.time, and surf.ce mineral deposits were penetrated by roots. The results were interpreted in the light of.present knowledge on the ef.ects of.soil animal activity on plant growth and survival of.seedlings.

关键词： dung beetle activity earthworm f.eces roots tropical ralnf.rests

Nanoparticle migration ef.ects on f.lly developed f.rced convection of.TiO2-water nanof.uid in a parallel plate microchannel

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Particuology 2016年第1期14卷 96-107页

作者： f. Hedayati G. Domairry Young Researchers and Elite Club Neyshabur Branch Islamic Azad University Neyshabur Iran Mechanical Engineering Department Babol University of Technology Babol lran

This study considers the f.rced convection of.laminar TiO2-water nanof.uid f.ow in a parallel plate microchannel. The small length scale associated with microchannels dictates the use of.slip condition at the f.id-solid interf.ce. The modif.ed Buongiorno model was employed f.r the nanof.uid to f.lly account f.r the ef.ects of.non-unif.rm viscosity and thermal conductivity. The partial dif.erential equa- tions associated with conservation laws were reduced to two-point ordinary boundary value dif.erential equations bef.re being numerically solved. Considering Brownian motion and thermophoresis, the ef.ects of.nanoparticle transport on concentration, velocity, and temperature prof.les were analyzed f.r three dif.erent values of.wall heat f.ux. To assess the ef.iciency of.adding nanoparticles, the ratios of.the pres- sure drop and the heat transf.r coef.icient of.the nanof.uid to that of.the base f.uid were studied in detail. f.om analyzing dif.erent heat f.ux ratios, one-sided heating was f.und to be most ef.icient at enhancing the heat transf.r rate in the microchannel. Additionally, in the presence of.the slip velocity, the increase in the value of.the heat transf.r coef.icient f.r the nanof.uid was smaller than that f.r the base f.uid.

关键词： Nanof.uid Microchannel Nanoparticles migration Slip velocity Brownian motion Thermophoresis

A passive-biped model with multiple routes to chaos

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Acta Mechanica Sinica 2011年第2期27卷 277-284页

作者： f. f.rshimi M. Naraghi Department of.mechanical Engineering Amirkabir University of Technology Tehran Iran

This paper presents a new passive-biped model consisting of.a simplest walking model beneath an upper body, with no kinematic constraint. The upper body is attached to the legs with a linear torsional spring. The model is a passive dynamic walker, so it walks down a slope without energy input. The governing equations of.motion are derived and simulated f.r the parameter analysis purposes. Simulation results reveal some dif.erent routes to chaos that have not been observed in previous models.

关键词： Passive-biped Routes to chaos Upper body Bif.rcation

Local Entropy Production in Turbulent Shear f.ows:A Tool f.r Evaluating Heat Transf.r Perf.rmance

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Journal of.Thermal Science 2006年第2期15卷 159-167页

作者： H. HERWIG f. KOCK Hamburg University of.Technology 21073 Hamburg Germany. BMW 80788 Munich Germany

Perf.rmance evaluation of.heat transf.r devices can be based on the overall entropy production in these devices. In our study we theref.re provide equations f.r the systematic and detailed determination of.local entropy production due to dissipation of.mechanical energy and due to heat conduction, both in turbulent f.ows. Af.er turbulence modeling has been incorporated f.r the f.uctuating parts the overall entropy production can be determined by integration with respect to the whole f.ow domain. Since, however, entropy production rates show very steep gradients close to the wall, numerical solutions are f.r more ef.ective with wall f.nctions f.r the entropy production terms. These wall f.nctions are mandatory when high Reynolds number turbulence models are used. f.r turbulent f.ow in a pipe with an inserted twisted tape as heat transf.r promoter it is shown that based on the overall entropy production rate a clear statement f.om a thermodynamic point of.view is possible. f.r a certain range of.twist strength there is a decrease in overall entropy production compared to the case without insert. Also, the optimum twist strength can be determined. This inf.rmation is unavailable when only pressure drop and heat transf.r data are given.

关键词： entropy production turbulent heat transf.r wall f.nctions