共查询到20条相似文献，搜索用时 31 毫秒
1.
The superconductor sample had periodic distribution of pinned region (with length ofL
p) and unpinned region (with length ofL−L
p) along the driving force direction. Numerical study on the influence of the distribution of pinning centers on pinning of
the two-dimensional vortex system showed that the critical depinning forceF
c, beyond which the vortex system begins to depin, increases with increase ofL
p, indicating that the homogeneity of pinning centers helps to enhance the critical electric current of a superconductor. We
found that the critical depinning forceF
c depends logarithmically onL/L
p.
Project supported by the Ministry of Science and Technology of China (NKBRSF-G19990646) and Zhejiang Proviace Foundation (199031). 相似文献
2.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｙｐｅＩＩｓｕｐｅｒｃｏｎｄｕｃｔｏｒｓｉｎａｓｕｆｆｉｃｉｅｎｔｌｙｓｔｒｏｎｇｍａｇｎｅｔｉｃｆｉｅｌｄｃｈａｎｇｅｔｏａｍｉｘｅｄｓｔａｔｅａｎｄａｖｏｒｔｅｘｌａｔｔｉｃｅ (ＶＬ)ｆｏｒｍｓ .Ｔｈｅｉｎｆｌｕｅｎｃｅｏｆｑｕｅｎｃｈｅｄｒａｎｄｏｍｐｉｎｎｉｎｇｓｏｎｔｈｅｖｏｒｔｅｘｌａｔｔｉｃｅｉｓａｓｕｂｊｅｃｔｏｆｌｏｎｇｓｔａｎｄｉｎｇｉｎｔｅｒｅｓｔ.Ｉｎａｐｐｌｉｃａ ｔｉｏｎｏｆｈｉｇｈ Ｔｃｓｕｐｅｒｃｏｎｄｕｃｔｏｒｓｉｎｓｔｒｏｎｇｍａｇ ｎｅ… 相似文献
3.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｂｕｒｉｅｄｐｉｐｅｌｉｎｅｃａｎｂｅｃｌａｓｓｉｆｉｅｄｉｎｔｏｔｈｒｅｅｄｉｆｆｅｒｅｎｔｔｙｐｅｓ .Ｄｕｅｔｏｔｈｅｄｉｆｆｅｒｅｎｃｅｏｆｔｈｅｒｅｌａｔｉｖｅｓｅｔｔｌｅｍｅｎｔｂｅｔｗｅｅｎｔｈｅｐｉｐｅａｎｄｔｈｅｓｏｉｌｃｌｏｓｅｔｏｉｔｓｔｗｏｓｉｄｅｓ ,ｔｈｅｖｅｒｔｉｃａｌｐｒｅｓｓｕｒｅｏｎｔｈｅｐｉｐｅｖａｒｉｅｓｄｉｆｆｅｒｅｎｔｌｙ .Ｗｈｅｎｔｈｅｆｉｌｌｉｓｈｉｇｈｅｎｏｕｇｈ ,ｔｈｅｖｅｒｔｉｃａｌｐｒｅｓｓｕｒｅｉｓｔｈｅｍｏｓｔ… 相似文献
4.
The properties of a two-dimensional vortex system with random columnar defects were studied by cooling the vortex system to
zero temperature. The vortex lattice became more and more disordered with increasing pinning strengthf
p. At smallf
p, a triangular vortex, lattice away from the pins was observed. The peak of structure factorS(G0) of the vortex lattice decreased with pinning strengthf
p, which accorded with the finding that the probability of vortex to be pinned increased withf
p. Some of our results agreed with experimental findings.
Project supported by the Ministry of Science and Technology of China (NKBRSF-G19990646) and Zhejiang Province Scientific Foundation
(199031). 相似文献
5.
《上海大学学报(英文版)》2007,11(1):58-58
Dynamic architecture of multi-agent systems (MAS) is important for critical systems. As the existing formal specifications of MAS cannot describe its dynamic architecture, a formal approach using $\piup$-calculus is presented, which is suited for the describing and analyzing of concurrent MAS with dynamic topology. $\piup$-calculus describes the belief-desire-intention (BDI) model that represents agent's mental states and provides many useful facilities to analyze MAS model such as deadlock, behavior equivalence, and model checking. To illustrate the favorable representation capability of $\piup$-calculus, an example of dynamic multi-agent systems in e-commerce is provided. Finally, by using an existing $\piup$-calculus supporting tool, MAS model and some key behaviors properties are analyzed and verified. 相似文献
6.
A parallel dynamic passive valveless micropump was designed, which consists of three layers-valve, diaphragm and electromagnetic coil. The valve was wetly etched in a silicon wafer, the diaphragm was a PDMS （polydimethyl siloxane） film spun on a silicon wafer with embedded permanent magnet posts, and the coil was electroplated on a silicon substrate. Under the actuation of the magnetic field generated by coils, the flexible diaphragm could be displaced upwards and downwards. After analyzing magnetic and mechanical characteristic of the flexible membrane and direction-dependence of the nozzle, a micropump was designed. And the relative length （L/d） of the micropump nozzle was taken 4. A 7 × 7 array of permanent magnetic posts was embedded in the PDMS film. Two diaphragms worked in an anti-step mode, which could relieve the liquid shock and increase the discharge of the micropump. The ANSYS and Matlab were adopted to analyze the actuation effect of the coil and the flow characteristic of the micropump. Results show that when actuated under a 0.3 A, 100 Hz current, the displacement of the diaphragm is more than 30 μm, and the discharge of the micropump is about 6 μL/s. 相似文献
7.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｐｏｔｅｎｔｉａｌｕｓｅｒｏｆｃｏｒｅｃｏｌｌｅｃｔｉｏｎｆａｌｌｓｉｎｔｏｔｈｒｅｅｍａｉｎｇｒｏｕｐｓ:ｐｌａｎｔｂｒｅｅｄｅｒｓｗｈｏｗｉｓｈｔｏｆｉｎｄａｎｄｕｔｉｌｉｚｅｇｅｒｍｐｌａｓｍ ;ｇｅｒｍｐｌａｓｍｓｐｅｃｉａｌ ｉｓｔｓｗｈｏｗｉｓｈｔｏｓｔｕｄｙｇｅｒｍｐｌａｓｍｏｒｇｅｎｅｔｉｃｖａｒｉ ａｔｉｏｎ ;ｃｕｒａｔｏｒｓｗｈｏｒｅｑｕｉｒｅａｓｓｉｓｔａｎｃｅｗｉｔｈｇｅｒｍ ｐｌａｓｍｍａｎａｇｅｍｅｎｔ (Ｍａｃｋａｙ ,1 995) .Ｇｅｒｍ ｐｌａｓ… 相似文献
8.
9.
为了解不同空调风机的内流机制,采用数值分析和PIV实验研究相结合的方法对空调用贯流风机和轴流风机内部复杂的旋涡流动现象进行了研究。结果表明:空调壁挂机用贯流风机内部偏心涡沿轴向具有明显的三维分布特性,偏心涡径向位置沿轴向几乎没有变化,其周向位置沿轴向不断改变。贯流风机偏心涡卷吸区域随负载提高而增强。高负载时,偏心涡更加靠近叶轮中心和蜗壳方向。空调室外机用开式斜流风轮的叶尖涡产生于距叶片前缘1/4区域,靠近吸力面。叶尖涡随风轮转速的提高而增强,并沿着与风轮旋向相反的方向朝下游发展。 相似文献
10.
Let G=(V, E)be a simple graph without isolated vertices. For positive integer κ, a 3-valued function f:V → {-1, 0, 1} is said to be a minus total k-subdominating function(MTκSF)if ∑u∈N(u)f(u)≥ 1 for at least κ vertices v in G, where N(v)is the open neighborhood of v. The minus total κ-subdomination number γ-κt(G)equals the minimum weight of an MTkSF on G. In this paper, the values on the minus total κ-subdomination number of some special graphs are investigated. Several lower bounds on γ-κt of general graphs and trees are obtained. 相似文献
11.
In this work, we made progress on the problem that lr(○×)lp(○×)lq is a Banach algebra under schur product. Our results extend Tonge's results. We also obtained estimates for the norm of the random quadralinear form A:lMr×lNp×lKq×lHs→ C, defined by: A(ei, ej, ek, es)=aijks, where the (aijks)'s are uniformly bounded, independent, mean zero random variables. We proved that under some conditions lr(○×)lp(○×)lq (○×)ls is not a Banach algebra under schur product. 相似文献
12.
超导体具有零电阻特性、完全抗磁性、通量量子化等优点,但受限于物理实验环境与材料自身特性,其临界温度测试一直是超导实验中的难点。对公开超导数据集进行研究分析,以期发现其临界温度与物理特性及化学元素组成之间的关系,进而构建能够辅助预测超导体临界温度的模型,降低实测获得临界温度的难度。结合数据挖掘领域的相关性分析与多元线性回归分析等理论,分别基于超导临界温度实验的物理属性数据及元素构成数据构建预测模型,为通过数据驱动实验获取其它超导体临界温度提供了有益尝试。通过对两个模型进行对比,结果表明,基于元素的预测模型效果略优于基于属性的预测模型。 相似文献
13.
采用二维有限元数值方法分析了焊接热影响区粗晶区（ＣＧＨＡＺ）中局部硬化区（ＬＨＺ）的作用。当含有ＬＨＺ时，大大提高了ＬＨＺ内的应力并引起应变在ＬＨＺ和基体界面处产生不连续分布。ＬＨＺ的形状强烈影响ＬＨＺ内部的应力，在细长ＬＨＺ内几乎整体均呈现高应力分布，而块状ＬＨＺ仅在边缘区域出现应力集中。即使ＬＨＺ含量相同，随ＬＨＺ细长比的增大，ＬＨＺ内峰值应力及高应力区面积增加，说明细长ＬＨＺ容易在低应力水平下诱发断裂。这一结果在高强钢焊接热影响区ＣＴＯＤ试验中得到证实。含细长ＭＡ组元的ＣＧＨＡＺ在低得多的ＣＴＯＤ水平下发生断裂，因此控制ＭＡ组元的形状能够大大改善ＣＧＨＡＺ的韧性。 相似文献
14.
Rui Yang 《Chinese Education & Society》2014,47(1):27-43
The educational exchange relationship between developed and developing (not accidentally non-Western) countries has always been characterized by imbalances and asymmetries. Accordingly, the traditional forms of North-South relationships have been between donors and recipients. International educational exchange between developed and developing countries needs to be located in a historical context of colonialism, and many constraints continue to pose barriers to genuine partnership. Today, neocolonialism is the relationship that developing countries have to deal with. The present international educational equation has certain institutional and intellectual "centers" that give direction, provide models, produce research, and in general function as the pinnacles of the academic system. At the opposite end of the spectrum are universities that are peripheral in the sense that they copy development from abroad, produce little that is original, and are generally not at the frontiers of knowledge. Educational institutions located in developing countries are strongly dependent on the institutions located in the centers.
Meanwhile, the contemporary academic world is becoming increasingly multipolarized. A critical mass of non-Western scholarship is emerging, and beginning to force a reconsideration of traditional concepts and theories. The latest work in research fields is done at many more centers of scholarship than before. China, a giant periphery, as some scholars describe it, is especially noticeable and should be treated seriously, with its massive investment on research and development. Based on long-standing observation of the Chinese higher education system, this article explores the maintenance of international links in Mainland Chinese universities, set in an international context. It ends with some critical comments and constructive suggestions, with particular regard to the genuine collaboration and reciprocity in international educational exchange between the best institutions in the developed countries and their Chinese peers. 相似文献
15.
ＩＮＴＲＯＤＵＣＴＩＯＮＭｕｃｈａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｒｅｃｅｎｔｌｙｔｏｔｈｅｓｔｕｄｙｏｆｓｐｉｎｐｏｌａｒｉｚｅｄｔｕｎｎｅｌｉｎｇｉｎｊｕｎｃｔｉｏｎｓｏｆｔｗｏｆｅｒｒｏｍａｇｎｅｔｓｓｅｐａｒａｔｅｄｂｙａｎｏｎｍａｇｎｅｔｉｃｔｕｎｎｅｌｉｎｇｂａｒｒｉｅｒ(Ｙａｏｉｅｔａｌ.,1993;Ｎｏｗａｋｅｔａｌ.,1992;Ｓｕｅｚａｗａｅｔａｌ.,1992;ＬｅＣｌａｉｒｅｔａｌ.,1994;Ｐｌａｓｋｅｔｔｅｔａｌ.,1994;Ｍｉｙａｚａｋｉｅｔａｌ.,1995;Ｔｅｚｕｋａｅｔａｌ.,1996).Ａｓｉｇｎｉ… 相似文献
16.
Let Γd2nbe the set of trees with a given diameter d having a perfect matching,where 2n is the number of vertex.For a tree T in Γd2n,let Pd+1be a diameter of T and q = d m,where m is the number of the edges of perfect matching inPd+1.It can be found that the trees with minimal energy in Γd2nfor four cases q = d 2,d 3,d 4,[d2],and two remarks aregiven about the trees with minimal energy in Γd2nfor2d 33q d 5 and [d2] + 1 q2d 33 1. 相似文献
17.
研究了Ag掺杂对Y—Ba—Cu-O系超导体临界温度Tc、临界电流密度Jc的影响，给出了改善Y—Ba—Cu-O系超导体临界电流密度Jc和其机械加工性能的途径，为其实际应用进行了有益的探索． 相似文献
18.
文章给出了转动参照系平面与水平面成任意角时有质负载弹簧匀速转动情况下弹簧中的应力分布及弹簧长度的公式,根据公式编写程序,绘图直观反映弹簧自身质量m、劲度系数七、旋转角速度ω和转动参照系平面与水平面的夹角θ等因素的影响． 相似文献
19.
不同光照强度对薇甘菊幼苗生长和形态的影响 总被引：13，自引：0，他引：13
比较了生长在不同光照强度下的薇甘菊 (Mikainamicrantha) 幼苗的生长型。结果表明 :苗高、节间长、比叶面积、叶面积比、总叶面积、净同化速率、支持结构生物量比、根生物量比和根冠比随着光照强度的变化而改变 ;然而 ,比茎长、比叶柄长、总生物量、相对生长速率和叶片生物量比却保持相对的稳定。说明薇甘菊幼苗对不同的光强梯度具有不同的可塑性和适应性。 相似文献
20.
配电系统在计算机机房运行过程中起着至关重要的作用,随着金融企业中心机房运行时间越来越长,机房的基础环境设施也逐步进入更新改造期,而其中的机房配电系统改造又成为整个机房改造的核心与关键。 相似文献