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61.
Hun Xue 《Materials Letters》2007,61(2):347-350
Macroporous nanocrystalline zinc ferrite with single spinel-phase was prepared by a facile self-propagating combustion method using zinc nitrate, iron nitrate and glycine. The as-prepared ZnFe2O4 were characterized by X-ray diffraction (XRD) analysis, N2 adsorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectrum (EDS). The magnetic properties of the prepared ZnFe2O4 were also studied. 相似文献
62.
简述轴承工作性质,巴氏合金应用与相组成的基本情况。论述汽轮机转子在两个电厂长期运行后,由于轴颈发生的不正常摩擦损伤,在大修改造中由无损检查、机械加工揭示出轴颈存在严重的渗巴氏合金现象,低熔点金属Sn、Sb与Cu向转子材料晶界的深层渗入最终导致了3根大型在投转子的严重开裂与报废。图11表2 相似文献
63.
64.
Parthasarathy P. Tirumalai Meng Lee Michael S. Schlansker 《The Journal of supercomputing》1991,5(2-3):119-136
Modulo scheduling theory can be applied successfully to overlap Fortran DO loops on pipelined computers issuing multiple operations per cycle both with and without special loop architectural support. This paper shows that a broader class of loops—REPEAT-UNTIL, WHILE, and loops with more than one exit, in which the trip count is not known beforehand—can also be overlapped efficiently on multiple-issue pipelined machines. The approach is described with respect to a specific machine model, but it can be extended to other models. Special features in the architecture, as well as compiler representations for accelerating these loop constructs, are discussed. Performance results are presented for a few select examples.An earlier version of this paper was presented at Supercomputing '90. 相似文献
65.
为了研究带电粒子光学系统的光学特性,需要知道系统中磁场的空间分布。实际磁场往往不具有严格的平面对称性质,一些作者曾就这类磁场的空间展开做过不少工作。但他们的工作是在柱坐标系统中进行的,适用于诸如回旋加速器、双向聚焦磁分析器、环形磁β谱仪等一类装置的磁场分析。对于大型同位素电磁分离器(calutron)那样一类装置,其磁场分布需要 相似文献
66.
67.
将信道传输容量动态分配技术应用于数字用户环路复用设备中,可用效地解决复用设备线路复用率和话音传输质量之间的矛盾,从而使复用设备具有最佳的传输效果。本文介绍了一种性能优良的统计复用信道的数字用户环路复用设备。 相似文献
68.
The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam)
were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m3 of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m3 and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m3 and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m3 and 2.3 kA/m for solid polycrystalline nickel. 相似文献
69.
自调Q掺饵光纤激光器 总被引:1,自引:0,他引:1
研制出一种结构新颖的掺饵光纤激光器,该激光器利用线性光纤环形镜和半导体激光器芯片的背向反射镜组成谐振腔。采用半导体激光器芯片作为饱和吸收体,在9mW的泵浦功率下,该激光器实现了自调Q脉冲输出。输出光脉冲宽度为12μs,脉冲峰值功率约为22mW,脉冲序列的重复周期约为65μs。 相似文献
70.
Variation of magnetic critical current density (J
mc) and transport critical current density (J
tc) in high magnetic fields at liquid helium temperature were investigated on Sm-Ba-Cu-O: Ag
x
(x=0.0, 0.2, 0.4, and 0.6) superconducting samples prepared by the coprecipitation technique.T
c
and crystallographic parameters remain unaffected by Ag addition. However, bothJ
mc andJ
tc were found to increase on Ag addition. The volume pinning force (F
p) also increased with increase in Ag concentration, resulting in stronger flux line sheer. Microwave-induced d.c. voltage measurement shows a significant reduction of the total number of weak links between the superconducting grains with increasing concentration of Ag, which creates stronger pinning potentials between the boundary of the superconducting intergrains. Hence, the volume pinning force is greatly enhanced by Ag addition, leading to flux line lattice movement which is responsible for highJ
mc andJ
tc. 相似文献