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111.
112.
In view of an excellent agreement between the recently determinedv
μ-hadron couplings and predictions of the standard model, the basic question discussed is how far its neutral current predictions
can be mimiced in going either from the isodoublet to an isotriplet (or an even higher isospin) left-handed representation
or from SU
L
(2) × U(1) toG × U(1), whereG is a simple group of rank two. This question is addressed with reference to a sufficiently broad class of schemes. Their
most distinctive properties are: in the higher isospin scheme, neutrino couplings are precisely in the form obtainable with
standard l.h. representation; the higher g.g. scheme isL+R type in which, to each light fermion of evenRU parity, a superheavy fermion of the same charge and oddRU parity is associated, parity conservation forbidding their mixing. Reasons for excluding theL-type andG
2 higher g.g. schemes are given. Their neutral current predictions are compared with those of the standard model. A higher
isospin representation can mimic the predictions of the standard model in inclusive and semi-inclusivev
μ-hadron reactions but is conclusively discriminated from the isodoublet representation by elasticv
μ
(−
p scattering. TheG × U(1) scheme can mimic standard model neutrino sector but is conclusively discriminated from minimal scheme by parity violating
effects. 相似文献
113.
114.
电流引线是室温电源电缆与低温磁体之间的电连接部件.高温超导材料在液氮温度下具有零电阻率和低热导率的特性,用它做成的电流引线可以大大减小低温系统的热负荷,从而减少制冷设备投资及系统运行费.高温超导电流引线可以分为阻性换热器段和高温超导段两部分(其中还包括各部件间的连接部分).高温超导段的分流器设计关系到冷端热负荷大小以及超导段失超后的安全问题.为了研究国际热核聚变试验堆(ITER)电流引线高安全性能,专门设计、试验了68kA引线的1/90实验样品.本文通过对比全CuBe(cu-2%Be)分流器、全不锈钢分流器和二元分流器的失冷故障(LOFA)实验结果,证明二元分流器能够克服安全性和冷端漏热矛盾,可以满足ITER高安全性的要求. 相似文献
115.
N. Aksel M. Scholle C. Fetecau 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(5):815-831
Analytical expressions for the velocity fields corresponding to the motions of an Oldroyd-B fluid due to oscillations of an
infinite flat plate as well as those induced by an oscillating pressure gradient and pressure jumps are determined by means
of the Fourier sine transform. The corresponding solutions for a Maxwell and a Newtonian fluid appear as limiting cases of
the solutions established here. Relevant physical properties of the flows and their dependence on material and geometry parameters
are discussed.
(Received: August 16, 2005; revised: December 19, 2005) 相似文献
116.
紧凑型回旋加速器作为重离子医学专用装置同步加速器的注入器,其引出系统设计所用的磁场为TOSCA模型计算磁场。通过单粒子轨道计算确定引出系统的元件类型及基本参数;通过多粒子跟踪确定最终的元件参数和束流参数。为了提高引出效率,改善引出束流品质,在引出位置磁场梯度较大的位置,安放了一块C型磁铁,以改善此处的磁场梯度。同时,为了消除此C型磁铁对主磁场的影响,在此区域安放了一对线圈。计算结果表明引出系统的设计能够保证引出束流的强度和品质符合同步加速器的要求。 相似文献
117.
Sensitivity of the tunneling current to electron energy is calculated in the context of scanning tunneling microscopy for the vacuum case by using an appropriate parameter. In addition, a mathematical relationship between this parameter and the phase associated with the involved Schrödinger wavefunctions is obtained. 相似文献
118.
文章研究一个带有贝努利反馈且系统服务台经常遭受启动故障的重新访问排队系统模型,利用线性算子半群理论,通过对描述其系统行为的偏微分方程组的研究,证明了该模型所描述的系统所确定的算子是闭稠定耗散算子,生成C0压缩半群,从而得到系统的适定性.在证明1是算子的预解点时,采用了共轭方法. 相似文献
119.
P. Mun F. C. Fonseca R. Muccillo R. F. Jardim 《Physica C: Superconductivity and its Applications》2003,390(4):363-373
A systematic study of the magnetic hysteresis in transport properties of polycrystalline YBa2Cu3O7−δ–Ag compounds has been made based on two kinds of measurements at 77 K and under applied magnetic fields up to 30 mT: critical current density Jc(Ba) and magnetoresistance R(Ba). The R(Ba) curves show a minimum in their decreasing branch occurring at B=Bmin which was found to be both the excitation current Iex and the maximum applied magnetic field Bam dependent. In addition, for a certain value of Bam>5 mT, we have observed that Bmin increases with increasing Iex and reaches a saturation value. The Jc(Ba) curves show a maximum in decreasing applied magnetic fields occurring at B=Bmax. We have also found that Bmax increases with increasing Bam and reaches a saturation value. The minimum in the R(Ba) and the maximum in Jc(Ba) curves were found to be related to the trapped flux within the grains. All the experimental results are discussed within the context of the flux dynamics and transport mechanisms in these high-Tc materials. 相似文献
120.