检索结果-南通市图书馆

influence of Shallow and Deep Cryogenic Treatment on Tribological Behavior of En 19 Steel

在线全文

学校读者我要写书评

暂无评论

Journal of iron and Steel Research international 2011年第9期18卷 53-59页

作者： D Senthilkumar i Rajendran Department of Mechanical Engineering Dr Mahalingam College of Engineering and Technology

The influence of cryogenic treatment on the wear resistance of En 19 steel was studied. Furthermore, a comparative analysis on the effect of Deep Cryogenic Treatment （DCT, 196℃× 24 h）, Shallow Cryogenic Treatment （SCT -80℃ × 5 h） and Conventional Heat Treatment （CHT） was done through dry sliding wear testing. The microstructures of CHT, SCT and DCT samples were also examined through scanning electron microscopy. The results indicated that the wear resistance of shallow and deep cryogenically treated samples is higher when compared to that of conventionally treated samples. X-ray diffraction pattern revealed that the transformation of retained austenite into martensite is responsible for the wear resistance improvement.

关键词： steel wear cryogenic treatment automotive

Energy Decay in Thermoelasticity with Viscoelastic Damping of General Type

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2015年第2期31卷 331-344页

作者： Muhammad i.MUSTAFA King Fahd University of Petroleum and Minerals Department of Mathematics and Statistics

in this paper we consider an n-dimensional thermoelastic system with viscoelastic damping. We establish an explicit and general decay rate result without imposing restrictive assumptions on the behavior of the relaxation function at infinity. Our result allows a larger class of relaxation functions and generalizes previous results existing in the literature.

关键词： Thermoelasticity viscoelastic damping general decay convexity

THE DRAG EXERTED BY AN OBLATE ROTATiNG ATMOSPHERE ON AN ARTiFiCiAL SATELLiTE

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2002年第9期23卷 1016-1028页

作者： KH.i.Khalil National Research institute of Astronomy and Geophsics-Helwan Cairo Egypt

A theory is formulated for the motion of an artificial satellite under the joint effects of Earth oblateness and atmospheric drag. The Hamilton ' s equations of motion are derived including the zonal harmonics of the geopotential up to J4 and the drag accelerations. The atmospheric model is an oblate rotating model in which the atmospheric rotation lags behind that of the Earth as the increasing distance from the Earth. The drag free problem is first solved via two canonical transformations to eliminate in succession the short and long period terms. An operator D is then defined and used to formulate the drag acceleration in terms of the double primed variables expressing the solution of the drag-free problem.

关键词： oblateness the Hamiltonian Lie transform

Machines as readers: A solution to the copyright problem

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第11期6卷 1179-1187页

作者： SHAMOS Michael i. School of Computer Science Carnegie Mellon University Pittsburgh PA 15213 USA Department of Computer Science University of Hong Kong Hong Kong China

Copyright and its international complications have presented a significant barrier to the Universal Digital Library （UDL）＇s mission to digitize all the published works of mankind and make them available throughout the world. We discuss the effect of existing copyright treaties and various proposals, such as compulsory licensing and the public lending fight that would allow access to copyrighted works without requiring permission of their owners. We argue that these schemes are ineffective for purposes of the UDL. instead, making use of the international consensus that copyright does not protect facts, information or processes, we propose to scan works digitally to extract their intellectual content, and then generate by machine synthetic works that capture this content, and then translate the generated works automatically into multiple languages and distribute them free of copyright restriction.

关键词： Universal Digital Library (UDL) Copyright Digital rights management Compulsory license Berne convention Public lending right Synthetic documents Machine translation

Measurement of R at VEPP-2000

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第6期34卷 669-674页

作者： i.B.Logashenko Budker institute of Nuclear Physics Novosibirsk State University

The new e^＋e^- storage ring, VEPP-2000, is being commissioned at Budker institute of Nuclear Physics, Novosibirsk. Measurement of the total cross section e^＋e^- → hadrons in the whole VEPP-2000 energy range is one ... 详细信息

关键词： hadrons pion form factor cross section muon magnetic moment

Modified Nonlinear Model of Arcsin-Electrodynamics

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2016年第7期65卷 59-65页

作者： S.i.Kruglov Department of Chemical and Physical Sciences University of Toronto

A new modified model of nonlinear arcsin-electrodynamics with two parameters is proposed and *** obtain the corrections to the Coulomb law. The effect of vacuum birefringence takes place when the external constant magnetic field is present. We calculate indices of refraction for two perpendicular polarizations of electromagnetic waves and estimate bounds on the parameter γ from the BMV and PVLAS experiments. it is shown that the electric field of a point-like charge is finite at the origin. We calculate the finite static electric energy of point-like particles and demonstrate that the electron mass can have the pure electromagnetic nature. The symmetrical Belinfante energy-momentum tensor and dilatation current are found. We show that the dilatation symmetry and dual symmetry are broken in the model suggested. We have investigated the gauge covariant quantization of the nonlinear electrodynamics fields as well as the gauge fixing approach based on Dirac's brackets.

关键词： vacuum birefringence energy-momentum tensor static electric energy dilatation current dual symmetry quantization Dirac's brackets

Simulation Environments: Challenges for Advancement

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 1993年第4期4卷 12-24页

作者： Tuncer i.ren Department of Computer Science University of OttawaOttawaOn KIN 6N5.Canada

A brief review of the basic terminology on simulation, simulation life-cycle activities such as model-based activities, behavior-oriented activities, and quality assurance activities is given. Then, the challenges and opportunities for the advancement of the state-of-the-art in simulation environments are discussed under the following headings: modelling environments, simulation environments, mixed simulation environments, and comprehensive simulation environments.

关键词： Modelling environments Simulation environments Mixed simulation environments Comprehensive simulation environments.

＂Could charm （＆ τ） transitions be the ＇poor princess＇ providing a deeper understanding of fundamental dynamics ？＂ or：＂Finding novel forces＂

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2015年第3期10卷 1-28页

作者： ikaros i. Bigi Department of Physics University of Notre Dame du Lac Notre Dame IN 46556 USA

We know that our Universe is composed of only - 4.5% ＂known＂ matter; therefore, our understanding is incomplete. This can be seen directly in the case of neutrino oscillations （without even considering potential other universes）. Charm quarks have had considerable impact on our under- standing of known matter, and quantum chromodynamics （QCD） is the only local quantum field theory to describe strong forces. it is possible to learn novel lessons concerning strong dynamics by measuring rates around the thresholds of [Q^-Q] states with Q = b, c. Furthermore, these states provide us with gateways towards new dynamics （ND）, where we must transition from ＂accuracy＂ to ＂precision＂ eras. Finally, we can make connections with τ transitions and, perhaps, with dark matter. Charm dynamics acts as a bridge between the worlds of light- and heavy-flavor hadrons （namely, beauty hadrons）, and finding regional asymmetries in many-body final states may prove to be a ＂game changer＂. There are several different approaches to achieving these goals： for exam- ple, experiments such as the Super Tau-Charm Factory, Super Beauty Factory, and the Super Z~ Factory act as gatekeepers - and deeper thinking regarding symmetries.

关键词： CKM matrix HQE & OPE CPV in △C≠ 0 ≠ △B &τ decays

Operators of quantum theory of Dirac's free field

维普期刊数据库评论

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 Physics C 2024年第12期48卷 73-106页

作者： ion i.Cotaescu West University of Timişoara V.Pârvan Ave.4RO-300223 TimişoaraRomania

The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[***.J.C 82,1073(2022)].This approach is generalized here,associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation,acting on mode *** framework allows an effective quantization procedure,giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators,the Pauli-Lubanski and position operators,or other spin-type operators proposed to *** attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing *** principal operators of this type,including the usual coordinate operator,are derived here for the first *** an application,it is shown that an apparatus measuring these new observables may prepare and detect oneparticle wave packets moving uniformly without Zitterbewegung or spin dynamics,spreading in time normally as any other relativistic or even non-relativistic wave packet.

关键词： Dirac theory integral operators Pryce's operators integral representations canonical quantization propagation