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1.
本文结合人民银行电视会议备份系统的建设.介绍了利用卫星组播技术实现电视会议系统备份的经验.希望能对读者提供一定的参考和借鉴作用。 相似文献
2.
通过赝势平面波法(CASTEP)及全电势线性缀加平面波法(FLAPW),以bcc-Fe为对象,研究第一性原理计算立方结构Fe基磁性材料弹性系数的方法,分析影响计算立方结构Fe基磁性材料弹性系数准确度的各项因素. 结果表明,在第一性原理弹性系数计算中,晶格常数是决定弹性系数计算准确度的关键因素;势函数的选择也会影响计算准确度. 使用全电势基矢的FLAPW法可以得到更为精准的弹性系数计算结果. 计算得到bcc-Fe的弹性系数C11,C12,C44分别为246 GPa,121 GPa,113 GPa,与实验值基本一致. 利用本方法,计算了新型Fe-Ga磁致伸缩材料的弹性系数C11,C12,C44分别为207 GPa,166 GPa及108 GPa.
关键词:
弹性系数
磁致伸缩材料
赝势平面波法
全电势线性缀加平面波法 相似文献
3.
VSAT卫星通信技术在上世纪90年代得到快速的发展,广泛地用于计算机通信网络的建设。2000年后,随着我国地面通信条件的改善,VSAT卫星通信系统由于其固有的特点,如覆盖范围广、通信与地理位置无关和可在一 相似文献
4.
“电机学”研究型课堂教学方案的探讨 总被引:3,自引:1,他引:2
本文探讨了"电机学"课程研究型教学方案.该方案内容涉及课程特点的分析、教材资源的配置、教学内容的设计、教学措施的研究和教学效果的评估五个方面.其教学目标是营造和谐的课堂教学氛围,追求教与学的相互协调.该方案已在教学实践中得到应用,取得了良好的成效. 相似文献
5.
The formation energies and electronic structures of Ni-rich Ni-Mn-Ga alloys have been investigated by firstprinciples calculations using the pseudopotential plane wave method based on density functional theory. The results show that the alloying Ni prefers to occupy the Mn site directly in Ni9Mn3Ga4 and to occupy the Mn site and drive the displaced Mn atom to the Ga site in NigMn4Ga3, which is in accordance with the experimental result. According to the lattice constants and the density of states analyses, these site preference behaviours are closely related to the smaller lattice distortion and the lower-energy electronic structure when the excess Ni occupies the Mn site. The effect of Ni alloying on martensitic transformation is discussed and the enhancement of martensitic transformation temperature by Ni alloying is estimated by the calculated formation energy difference between austenite and martensite phases. 相似文献
6.
First principles study on the magnetocrystalline anisotropy of Fe--Ga magnetostrictive alloys 下载免费PDF全文
This paper investigates the electronic structure and
magnetocrystalline anisotropy of Fe--Ga magnetostrictive material by
means of the full potential-linearized augmented plane-wave method
within the generalized gradient approximation. The 3d-orbit
splitting of Fe atoms in D03, B2-like and L12 crystalline
structures of Fe--Ga is calculated with consideration of the crystal
field as well as the spin--orbit coupling effect. Because of the
frozen orbital angular momenta of the 3d-orbit for Fe atoms in Fe--Ga
magnetostrictive alloys and the spin--orbit coupling, the
distribution of the electron cloud is not isotropic, which leads to
the anisotropy of exchange interaction between the different atoms.
A method on estimating the magnetocrystalline anisotropy of Fe--Ga
alloys by means of calculating orbit-projected density of states for
Fe atoms is performed. The anisotropic distribution of the electron
cloud of Fe atoms in these three crystalline structures of Fe--Ga is
studied based on the above method showing the highest magnetic
anisotropy for B2-like structure. This qualitative method comes
closer to physical reality with a vivid physical view, which can
evaluate the anisotropy of electron cloud for 3d transition atoms
directly. The calculated results are in good agreement with both the
previous theoretical computation and the tested value on the
magnetic anisotropy constant, which confirms that the electron cloud
anisotropy of Fe atoms could well characterize the
magnetocrystalline anisotropy of Fe--Ga magnetostrictive material. 相似文献
7.
中国金融卫星通信网是由中国人民银行组建的、由金融清算总中心负责管理运行的网络,是为全国银行系统及其他金融机构提供广域网服务的通信网络。自1989年国务院批准建设中国金融卫星通信网、1991年正式开通以来,经过8年建设,已经具有一定的规模。目前已建有两个卫星主站和648个卫星小站,覆盖了全国600多个城市及部分县。目前金融卫星通信网主要为全国电子联行(EIS)业务提供服务。 相似文献
8.
徐惠彬 《信息安全与通信保密》2006,(9):123-125
网络层加密手段作为保护通信安全的一种重要手段,越来越受到用户的重视和喜欢。文章没有从原理、设计等角度来分析网络层加密手段,而是从一个用户更加关心的问题来分析如何部署网络层加密产品,提出了几种主要的部署方式,供大家参考和交流。 相似文献
9.
采用区熔法制备了Ni50550.5Mn2424Ga25525.5取向晶体,在底部、中部和顶部各切取一块样品进行相变应变测试.在中部样品中获得了高达14%的相变应变,应变随加热冷却循环次数的增加而逐步降低,第9次和第10次相变时应变为08%.在底部和顶部样品中,降温过程的应变随温度的变化呈现先收缩后膨胀或先膨胀后收缩的现象,我们认为这是由于样品中高度择优取向的马氏体变体竞争的结果所致.
关键词:
NiMnGa
取向晶体
相变应变 相似文献
10.