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Processes of quasistatic and dynamic magnetization reversal have been studied for the case of planar 6 × 6 lattices of magnetic nanodipoles that possess a cubic crystallographic anisotropy. The response of the total magnetic moment to a magnetic-field pulse of various duration and polarization have been determined for different equilibrium configurations of the lattices. Along with the in-plane configurations of magnetic moments, configurations with one and two dipoles oriented perpendicular to the plane of the lattices have been considered. 相似文献
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The performed studies allowed us to obtain a composite with regulated structure formation at ?? ?? 0.06 vol % of copper and directed changes of the electrophysical properties in a dielectric using the explosion of a conductor. 相似文献
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A. Almazrouee S. Al-Faheed H. M. Shalaby 《Journal of Materials Engineering and Performance》2013,22(5):1436-1442
Cobalt-based alloys of the Stellite family are used as hardfacing for sealing surfaces of valves operating in desalination and power plants because of their excellent low friction and anti-galling properties in high-load sliding contact under the prevailing conditions. However, insufficient control of pressure and temperature during operation can degrade the integrity of the hardfaced material thus leading to its premature failure. This article presents a failure investigation carried out on the disk of a main stop gate valve that was used in a desalination plant. The disk was manufactured from X20 as a substrate material and a cobalt-based alloy for hardfacing. The cobalt-based hardfacing suffered from many surface and subsurface cracks that degraded its integrity. It was concluded that high-pressure steam flowing against the disk had tilted it and, thus, disturbed the alignment between the surfaces of the disk and the seat, leading to wear and large frictional heat that resulted in the degradation of the microstructure of the hardfacing layer and formation of the observed cracks. 相似文献
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M. A. Shamsutdinov V. N. Nazarov I. Yu. Lomakina 《The Physics of Metals and Metallography》2006,101(4):309-319
This paper is devoted to a theoretical investigation of the effect of an applied magnetic field and damping on the dynamics of magnetization-reversal nucleus represented by interacting domain walls (DWs) with opposite topological charges. It is shown that at initial amplitudes that are less than the amplitude of the critical nucleus of magnetization reversal, nonlinear vibrations of strongly interacting DWs are observed. In the presence of dissipation, the nonlinear vibrations are damped vibrations with a frequency that changes with time. At the initial amplitudes that are greater than the amplitude of the critical nucleus, the magnetization-reversal nucleus decays with the formation of a solitary domain. The motion of two interacting 180° DWs relative to their common immobile center in fields that are less than the Walker field is translational; in higher fields, it is oscillatory. It is shown that DW vibrations are accompanied by a periodic transformation of their structure from Bloch into Néel and vice versa with a frequency that depends on the field, damping, quality factor, and the initial amplitude of the magnetization-reversal nucleus. 相似文献
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PHILIP R. VAN LOOCKE 《连接科学》1991,3(4):367-380
We consider the network studied by Amit et al. (i.e. a network that is quite closely related to the Hopfield model). We show that it is possible to save a significant amount of connections if it is reinterpreted as a two-layer system. One of the layers can be interpreted as the basis layer and the other one as a meta-layer. This system is suited for the storage of orthogonal groundstates. However, an extension of the meta-layer allows one to store mixture-states (multicomponent states) as well. This bears a system in which taxonomies as well as looser associative links can be stored. Due to the topological properties of the mixture-states, the system can be provided with a learning rule according to which the memories reorganize in a way that is suited for some aspects of genetic psychology 相似文献
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目的解决镀镍层可焊性不良的问题,使得光电子器件外壳镀镍层可焊性满足回流焊要求,并且保存半年后可焊性不降低。方法以氨基磺酸镍为体系,考察温度、p H值、电流密度与沉积速率的关系,采用回流焊和浸润法对镀层可焊性进行表征,并考察镀层的质量、结合力及盐雾性能指标。结果镀液体系在比较宽泛的电流密度和温度范围内,都能得到可焊性优良的镀层,其沉积速率随电流密度的增大呈线性增加。浸润法和回流焊接试验表明,镀层可焊性满足要求。在稳态湿热(45℃,RH=95%)环境中48 h或恒温烘烤(150℃,1 h)后,镀层可焊性仍均满足要求。结论在电流密度1~5 A/dm2,p H值3.2~4.4,温度40~55℃的条件下能得到优良的可焊性镀层,满足回流焊对镀层可焊性的要求,并且放置半年后可焊性不降低。 相似文献
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An analytical expression is constructed to estimate the influence of a surface electric charge on the drift velocity caused by the propagation of a wave packet on a horizontal surface of an ideal fluid. It has been shown that the surface electric charge affects the drift most effectively if the wavenumber of the carrier wave is equal to the inverse value of the capillary constant. Common regularities of the drift motion are established. 相似文献
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Fukumoto M. Matsumura Y. Hayashi S. Sakamoto K. Kasama A. Tanaka R. Narita T. 《Oxidation of Metals》2003,60(3-4):335-346
To protect Nb–5Mo–15W alloy against high-temperature oxidation a novel coating was developed involving electroplating of a Re–Ni film, followed by pack cementation with Cr and Al. The coating consisted of a duplex-layer structure, an inner (Re–Cr) or Re(Cr) layer and an outer Cr(Al) or NiAl layer. The Re–Ni film containing more than 70at.%Re, developed in the present investigation, is more useful than the conventional low Re–Ni film. The inner (Re–Cr) and Re(Cr) layer acts as a diffusion barrier between the Nb–5Mo–15W alloy substrate and the outer -Cr(Al) or -NiAl layer, which forms a protective -Al2O3 scale. The coated Nb–5Mo–15W alloy was oxidized in air at 1373K for up to 360ks, showing very good oxidation resistance. 相似文献
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A. E. Korneev V. N. Lovchev I. L. Kharina D. F. Gutsev 《Protection of Metals and Physical Chemistry of Surfaces》2017,53(7):1235-1239
Results of an investigation of the morphology of cracks that form during the operation in the weld joint of a heat-carrier drum with the steam-generator housing of nuclear-power plant with a VVER-1000 unit are given. The reasons for the formation of cracks are the compound-stress state of weld units, the corrosive effect of the heat carrier, and the operating temperature. Crack formation proceeds according to the delayed stress corrosion cracking on the internal surface of metal upon contact with the corrosion medium. The features of crack formation and propagation mechanism should be considered during remedial measures that are aimed at the maintenance of the reliability of the weld joint of a drum with the steam-generator housing of VVER-1000 units. 相似文献
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一、中国循环经济的内涵
我国循环经济的内涵可概括为:对社会生产和再生产活动中的资源流动方式实施了"减量化、再利用、再循环和无害化"管理调控的,具有较高生态效率的新的经济发展模式. 相似文献
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This paper proposes ISCL, Integrated Service CAD and Life cycle simulator. ISCL plays the role of CAD/CAE tools for product design in Product Service Systems (PSSs) design. In ISCL, the service CAD supports systematic generation of alternative PSSs based on service modeling, and the life cycle simulator analyzes their economic and environmental performances. The current study applies ISCL to the design of a PSS that includes functional upgrading service of a product, whose life cycle costs are sensitive to both its functional obsolescence and physical deterioration. Performances of alternative PSSs are investigated under different market and technology conditions. 相似文献
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《International Journal of Machine Tool Design and Research》1986,26(2):85-97
This paper shows how the cost of an existing foundation for a large machine can be minimized by optimizing the parameters which define its shape whilst maintaining the required stiffness. The parameters considered include the thickness of the concrete in the machine pit and the platform, the cross-sectional area and the amount of reinforcement in the piles, the number of piles and the spacing between them. The foundation is optimized using two- and three-dimensional models. Both these models have been optimized for different loading conditions and varying stiffnesses.A non-linear unconstrained optimization technique combined with the finite element method has been used to obtain the optimal designs. 相似文献
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M. A. Borich V. V. Smagin A. P. Tankeyev 《The Physics of Metals and Metallography》2014,115(8):737-743
Specific features of the heat capacity, magnetization, and magnetic susceptibility of a chiral magnet caused by the magnon contribution have been studied. It has been shown that the local heat capacity and the magnetization are functions of the coordinates and that their behavior depends on the magnitude of an applied magnetic field. The temperature dependences of these quantities have been investigated. The results of the approximate analytical calculations and numerical calculations have been compared between themselves. 相似文献