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31.
32.
Chirped fiber grating was used in dispersion compensator. We tried to use the same phase mask to write fiber grating of different wavelength with two methods to reduce the price of the fiber grating. 相似文献
33.
Tetraalkyltin complexes, SnR4 (R = Me, Et, Pr, Bu) could react with Pt/HY at 193, 243, 273 and 333 K, respectively. The reactions occurred on the surface of the zeolite and the organotin grafted zeolites were characterized in detail. The framework and the microporous structure of the grafted Pt/HY zeolites were retained. However, the modified zeolites showed better size selectivity in the absorption of hydrocarbons. 相似文献
34.
The growth mechanism of the peritectic η phase involving the peritectic reaction and peritectic transformation in Cu-70%Sn alloy was investigated under directional
solidification. The results show that a major growth mechanism in thickening of the peritectic η-layer is not the peritectic reaction but the peritectic transformation. The transformation temperature and isothermal time
play crucial roles in determining the volume fraction and the thickness of the peritectic η phase. With the increase of the temperature and isothermal time, the volume fraction of the peritectic η phase increases. The regressed data show that the relationship between the thickness of η phase (Δx) and the transformation temperature (T) meets the following equation In Δx=6.5−1673 1 / T. Additionally, there exists a relationship between the thickness of the η phase (Δx) and the isothermal time (t) at the 9 mm solidification distance below the peritectic reaction interface, Δx=0.72t
1/2, which is consistent with the theoretical model.
Supported by the National Science Foundation of China (Grant No. 50395102) 相似文献
35.
36.
本文报道了一种测角单晶NMR探头。该探头采用单线圃双调谐电路,工作频率在90MHz-110 MHz连续可调,可进行交叉极化大功率去耦实验。文中提出了一种简单而有效的测角装置,可使单晶绕三个互相垂直轴转动实现单晶的NMR测量。作为典型的应用例子,本文利用该探头实现了单晶DGO(2NH2CH2COOH·H2C2O4)屏蔽张量的测量。 相似文献
37.
平衡规划问题的熵函数方法及其在混合交通流中的应用 总被引:1,自引:0,他引:1
将参变极值问题的极大熵函数方法应用到求解平衡规划问题中,通过先验分布信息和Kullback熵概念,给出了平衡规划问题基于Kullback熵表示的熵函数求解方法,并将平衡规划的极大熵函数方法应用于求解混合交通平衡分配问题. 相似文献
38.
Xun Fu Danmei Wu Xiaodong Zhou Huaqiang Shi Zhengshui Hu 《Journal of nanoparticle research》2007,9(4):675-681
Hollow spherical molybdenum disulfide has been successfully synthesized via a solvothermal method using Cyanex 301 as sulfur
source and modification agent. The hollow spheres are characterized by transmission electron microscopy, scanning electron
microscopy, X-ray diffraction and Energy-Dispersive X-ray analysis. The influences of reaction conditions are also discussed
while a mechanism is proposed to explain the formation of the peculiar morphology. 相似文献
39.
SnO2 was added to high-permeability MnZn ferrites and MnZn ferrites for high-frequency power supplies. The effects of the SnO2 addition were studied. Sn4+ ions can dissolve into the spinel lattice and form stable Fe2+–Sn4+ pairs and hence can compensate the magneto-crystalline anisotropy constant K1 and improve the initial permeability effectively. The initial permeability of ferrites is also improved as abnormal grain growth caused by ion vacancy is controlled with SnO2 doping. In addition, the SnO2 doping also leads to a decrease in the relative loss factor and an increase in density. The power loss and minimum power loss temperature decrease with SnO2 doping. 相似文献
40.
S.G. Li G. Fu I. Reading S.B. Tor N.H. Loh P. Chaturvedi S.F. Yoon K. Youcef-Toumi 《Applied Physics A: Materials Science & Processing》2007,89(3):721-728
Micro powder injection molding (μPIM) is one of the potential processes for the mass production of metallic microstructures
and micro components. Here, μPIM is the miniaturization of conventional PIM, which involves four processing steps: mixing,
injection molding, debinding and sintering. This paper looks into the feasibility and effectiveness of μPIM as a key mass
production process for the fabrication of metallic micro components. For it to be an effective re-production process, it is
imperative to examine how well parts can be duplicated/fabricated from a master mold. In this work, the dimensional variation
of high-aspect-ratio micro-pillars arrays, in particular the dimensional shrinkage, global warpage, and surface roughness
at each stage of the μPIM process for a range of molding pressures, are quantified and compared in detail. The sensitivity
of the dimensional variation of the microstructures to the packing pressure is reported. The mechanism behind the dimensional
variation is analyzed.
PACS 81.20.Ev; 81.20.Hy; 81.70.Fy; 07.60.Ly; 81.05.-t 相似文献