检索结果-南通市图书馆

Phase Homogeneity and crystal Structure of Sb_(88)Te_(12) Synthesized by Melt-quench Method

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 441-446页

作者： c.Rangasami Department of Physics Erode Sengunthar Engineering College

Phase homogeneity and crystal structure of SbsaTe12 alloy synthesized by melt-quench method have been analyzed using X-ray diffraction （XRD） and Raman spectroscopy. Rietveld refinement of crystal structure of Sb8sTe12 has revealed the formation of SbsTe3 and Sb phases respectively with 11R and A7 structures （space group is R3m）. Phase fractions of the phases SbsTe3 and Sb have been determined to be 44.44% and 55.56% respectively. Raman spectrum of SbssTe12 has showed a highest intensity peak at 156 cm-1 and another peak at 151.1 cm-1, which correspond to Alg modes of SbsTe3 and element Sb, respectively. Analysis of Raman spectrum has substantiated the results obtained from structure refinement regarding the presence of two different phases.

关键词： SbssTe12 alloy Melt-quench method XRD Rietveld refinement Raman spectroscopy Multiphase formation

POSITRON LIFETIME STUDY OF THERMALLY INDUcED MIcROSTRUcTURAL cHANGES IN NISTARI SILK FIBER

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2003年第3期21卷 325-332页

作者： c.Ranganathaiah Department of Studies in Physics University of Mysore Manasagangotri Mysore-570 006 India

Positron lifetime measurements have been made in natural polymer-Nistari silk fibers as a function of isochronalannealing temperature in the range of 27℃ to 280℃. The variations in the positron results indicate the structural changesoccurring in the Nistari silk fibers and determine the glass transition temperature as 170℃. Activation energies weremeasured separately for the crystalline and amorphous regions indicating the versatility of the technique. These values areclose to the N--H bond dissociation energy, suggesting N--H bond dissociation as the most probable process occurringduring thermal treatment As an extension of the positron results, the molecular weight of the Nistari silk fibers wasdetermined to be 10.7×10~5 based on free volume, which lies within the range suggested for the silk fibers. There seems to bean indication that cross-linking changes the spiral structure of cotton fibers to network type. However, this needs to be validated by other techniques.

关键词： Nistari silk fiber Positronium Free volume Molecular weight Activation energy

ON BOUNDARY TREATMENT FOR THE NUMERIcAL SOLUTION OF THE INcOMPRESSIBLE NAVIER-STOKES EQUATIONS WITH FINITE DIFFERENcE METHODS

在线全文

学校读者我要写书评

暂无评论

Journal of computational Mathematics 1996年第2期14卷 135-142页

作者： Huang L c 中科院计算数学与科学工程计算所北京

The cross section calculation of 112Sn(α,γ)116Te reaction with different nuclear models at the astrophysical energy range

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2017年第8期28卷 103-109页

作者： c. Yalcin Department of Physics Kocaeli University 41380 UmuttepeKocaeli Turkey

The theoretical cross section calculations for the astrophysical p process are needed because most of the related reactions are technically very difficult to be measured in the laboratory. Even if the reaction was measured,most of the measured reactions have been carried out at the higher energy range from the astrophysical ***, almost all cross sections needed for p process simulation have to be theoretically calculated or extrapolated to the astrophysical energies.^(112)Sn(α,γ)^(116)Te is an important reaction for the p process nucleosynthesis. The theoretical cross section of ^(112)Sn(α,γ)^(116)Te reaction was investigated for different global optical model potentials,level density, and strength function models at the astrophysically interested energies. Astrophysical S factors were calculated and compared with experimental data available in the EXFOR database. The calculation with the optical model potential of the dispersive model by Demetriou et al., and the back-shifted Fermi gas level density model and Brink-Axel Lorentzian strength function model best served to reproduce experimental results at an astrophysically relevant energy region. The reaction rates were calculated with these model parameters at the p process temperature and compared with the current version of the reaction rate library Reaclib and Starlib.

关键词：核反应模型天体物理学截面计算能量范围光学模型势模型参数计算函数模型能级密度

Some studies on transient behaviours of sheath formation in dusty plasma with the effect of adiabatically heated electrons and ions

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2017年第9期19卷 35-40页

作者： G c DAS Gyan Darshan Academy VIP RoadGuwahati-781022India

Based on quasipotential analysis, a plasma sheath is studied through the derivation of the Sagdeev potential equation in dusty plasma coexisting with adiabatically heated electrons and ions. Salient features as to the existence of sheaths are shown by solving the Sagdeev potential equation through the Runge–Kutta method, with appropriate consideration of adiabatically heated electrons and ions in the dynamical system. It has been shown that adiabatic heating of plasma sets a limit to the critical dust speed depending on the densities and Mach number, and it is believed that its role is very important to the sheath. One present problem is the contraction of the sheath region whereby dust grains levitated into the sheath lead to a crystallization similar to the formation of nebulons and are compressed to a larger chunk of the dust cloud by shrinking of the sheath. Our overall observations advance knowledge of sheath formation and are expected to be of interest in astroplasmas.

关键词： sheath heated dynamical Kutta Runge derivation shrinking coexisting grains compressed

在线全文

学校读者我要写书评

暂无评论

小规模家禽养殖生物安全改进策略

中国家禽 2009年第24期31卷 45-46页

作者： E.G.Bleich P.pagani N.Honhold 苏扬联合国粮食与农业组织

H5N1高致病性禽流感病毒肆虐全球十多年来，发生禽流感的国家越来越多，并陆续入侵无高致病性禽流感的国家。许多国家，大多数疫情发生在由庭院散养和小规模商业生产组成的小规模家禽养殖业。尽管如此，与大型集约化养禽相比，小规模养... 详细信息

H5N1高致病性禽流感病毒肆虐全球十多年来，发生禽流感的国家越来越多，并陆续入侵无高致病性禽流感的国家。许多国家，大多数疫情发生在由庭院散养和小规模商业生产组成的小规模家禽养殖业。尽管如此，与大型集约化养禽相比，小规模养禽模式更多样且受疫病侵扰的实际几率更低，至少某些国家是这样。

关键词：家禽养殖业小规模高致病性禽流感病毒生物安全 H5N1 疫情发生集约化养禽

风之王者 2011pagani HUAYRA

在线全文

学校读者我要写书评

暂无评论

汽车与运动 2011年第3期 20-23页

作者：李晓非 pagani

7年的等待终于没有白费,pagani为我们带来了安第斯山脉的＂风之王者＂。在无数的谍照及吊人胃口的预览视频公布后,Pagarnj全新的超级跑车Huayr终于登场亮相。

关键词：安第斯山脉超级跑车胃口

Theoretical Model of Steel continuous casting Technology

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2009年第1期16卷 12-16页

作者： c Gheorghies I crudu c Teletin c Spanu Faculty of Science Dunarea de JosUniversity of GalatiRO800008Romania Faculty of Mechanical Engineering Dunarea de JosUniversity of GalatiRO800008Romania

A theoretical model adapted for studying steel continuous casting technology was proposed. The model based on system theory contained input/output, command, and control parameters. The process was divided .into five stages, i. e. , tundish, mold, guiding system, guiding-drawing system, and guiding-drawing-soft reduction system. The model can be used to describe the physicochemical processes, thermal processes, chemical processes, and characteristics of the cast material according to the above-mentioned stages. It can also be applied to other metallurgical technologies and even to other industries （chemistry, food, etc. ）.

关键词： steel casting technology system theory modeling

Evidence-based guidelines for greener,healthier,more resilient neighbourhoods:Introducing the 3–30–300 rule

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2023年第3期34卷 821-830页

作者： cecil c.Konijnendijk Nature Based Solutions Institute BarcelonaSpain

The important contributions of urban trees and green spaces to for example,climate moderation and public health have been *** paper discusses guidelines and norms that promote the benefi ts of viewing green,living amongst green,and having easy access to green spaces for recreational *** trees and other vegetation in sight from one’s home,place of work,or school has important mental health and performance benefi *** tree canopy cover is positively associated with cooling and other aspects of climate *** public green spaces in proximity to one’s home stimulates regular use of these areas and results in positive impacts on mental,physical,and social *** analyzing existing guidelines and rules for urban green space planning and provision,a new,comprehensive guideline is presented,known as the‘3–30–300 rule’for urban *** guideline aims to provide equitable access to trees and green spaces and their benefi ts by setting the thresholds of having at least 3 well-established trees in view from every home,school,and place of work,no less than a 30%tree canopy in every neighbourhood;and no more than 300 m to the nearest public green space from every *** implementation of this new guideline is discussed,as well as the advantages and disadvantages of using this evidence-based but also clear and simple rules.

关键词： climate adaptation Guidelines Public health Trees Urban forestry