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41.
共掺Tb,Gd偏硅酸钙(CaSiO3)的发光性质 总被引:5,自引:0,他引:5
采用高温固要反就法合成出单掺Tb和共掺杂Tb,Gd的CaSiO3多晶粉末样品,研究了其发光性质。在365mm下激发CaSiO3:Tb在可见光区具有由^5D4-^7F6跃迁引起的蓝光发射和由^5D4-^7F5跃迁引起的绿光发射,随着Tb^3 离子浓度的增加^5D3能级发生猝灭而增加^5D4能级的发射。共掺杂样品由于Gd^3 离子的加入,极大的提高了Tb^3 的发光强度,由于能级匹配,Gd^3 离子通过无辐射共振能量传递敏化Tb^3 的变化。 相似文献
42.
The behaviour of organic matter in the process of soft soil stabilization using cement 总被引:1,自引:1,他引:0
In some projects where cement is used to stabilize soft soil foundations, it is found that the organic matter influences the
stabilization effect. As a consequence, extra admixtures are added to accelerate the reactions of cement and improve the stabilization
effect. In this study, different kinds of extra admixtures were used with cement to stabilize a soft soil with a high organic
content. Direct shear and unconfined compression tests were undertaken and the mechanical indices in different conditions
obtained. The total amount and components of the organic matter in every sample were also determined. The results show that
the addition of extra admixtures improves the properties of cement-stabilized soils and that different extra admixtures play
a different role.
相似文献
43.
侧向测井曲线分辨率匹配方法及其在松辽盆地的应用 总被引:4,自引:1,他引:3
对于松辽盆地中的一些较薄的致密砂岩储层,常规测井曲线,尤其是电阻率测井曲线,因为它们的纵向分辨率较低,往往会降低薄储层含油饱和度的计算精度。为此,探讨了应用“分辨率匹配”方法,将低分辨率的曲线提高为具有较高分辨率的曲线。并利用地层界面处的测井曲线变化率来提取实际的综合响应函数,而不是直接使用测井仪器的响应函数,因此使提高分辨率的处理更符合实际。最后给出了将深浅侧向电阻率测井曲线的分辨率提高到微球形聚焦测井分辨率的应用实例。 相似文献
44.
研究了金铜精矿压氧浸出后高铜低铁料液中铜铁的萃取分离。利用P507萃取浸出液中的铁,0.01 mol/L硫酸洗涤有机相,6.0 mol/L盐酸反萃,萃铁后液以Na2CO3沉铜,硫酸溶解该沉淀后,可送铜的精练。铜铁分离系数为1 030,铜回收率可达96.26%。 相似文献
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47.
In order to improve the carrying capacity and reduce the temperature rise in high speed and precise spindle systems, a combined surface radial sleeve bearing using the interfacial slip technique was discussed. An extended Reynolds equation was derived based on the modified slip length model considering the limiting shear stress. By means of the finite differential methods, the characteristic analysis and optimization of the slip region of the combined surface sleeve bearing were carried out, and it has been proved that there is still a considerable large load support in a parallel sliding gap. Comparing with the general journal bearing, the load capacity and end leakage rate of the combined surface sleeve bearing can be increased greatly and the load capacity can be increased by 1.75 times. The attitude angle, friction drag, temperature rise of the combined bearing can be decreased distinctly and the temperature rise can be decreased by 92.4%. 相似文献
48.
拟线性近似方法是Zhdanov在研究电磁散射正反演问题的过程中提出的一种近似方法。由于稳定电流场的积分方程与电磁散射的积分方程具有相似性,所以可以利用拟线性近似方法来研究稳定电流场的问题。能否用简便可行的方法求出参数是决定这种方法有效性的关键。针对稳定电流场的特点,本文重点探讨了在几种常见的简单地电模型中参数的变化规律。研究结果表明,对于在直流电法勘探中常见的情况,参数可以认为是位置的慢变函数,并且可以用比较简便的方法求得。这个研究结果为利用拟线性近似方法实现稳定电流场的快速反演打下了基础。 相似文献
49.
Effects of Bi and rare earth metal on the microstructure and properties of Zn-based high-temperature solder
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A novel Zn-based high-temperature solder was developed to join copper/steel at moderate temperature. The effects of Bi and rare earth metal on the microstructures, wettability of solders as well as the mechanical properties of solder joints were investigated. The results indicated that with the addition of Bi into Zn-Cu-Sn (ZCS) alloy, significant improvement in wettability is realized. When the content of Bi element is 1.5 wt. % in the solder, the spreading area researched over 200 mm2. Further more, with the addition of RE, refined primary ε-CuZn5 phases were formed and the shear strength of the solder joint was largely improved. 相似文献
50.
Wanling Shen Jun Yang Shenhui Li Wei Hu Jun Xu Hailu Zhang Qin Zou Lei Chen Feng Deng 《Microporous and mesoporous materials》2010,127(1-2):73-81
The phase transition process from a hexagonal to a lamellar mesostructured aluminophosphate was studied by multinuclear solid-state NMR techniques in combination with low-angle XRD and elemental analysis measurements. The XRD result showed that after hydrothermal treatment for 9 h, the initial hexagonal phase began to transform to a lamellar phase. It was also found by NMR that some initially formed aluminophosphate was hydrolyzed during the earliest 2 h of the hydrothermal treatment, and the inorganic aluminophosphate framework became more and more condensed during the phase transition. The organic surfactant mainly has a gauche conformation in the hexagonal phase, whereas it mainly has a trans conformation in the lamellar phase and is packed more compactly. The Br? anion is found to be involved in the phase transition and likely enters into the interface to compensate the lost of negative charges that generated by the condensation of the aluminophosphate. Finally, a mechanism for the phase transition is proposed. 相似文献