不同类型石英玻璃的振动能量损耗特性对比分析

石英玻璃相对于金属、晶体、陶瓷等大多数固体材料具有更小的机械振动能量损耗,是许多精密测量器件的首选材料。本文测试对比了四种类型(Ⅰ类、Ⅱ类、Ⅲ类和Ⅳ类)石英玻璃的振动能量损耗特性,从材料化学组分和结构缺陷方面分析了石英玻璃本征损耗的影响因素及作用机理。结果表明:Ⅰ类和Ⅱ类石英玻璃的本征损耗显著大于Ⅲ类和Ⅳ类石英玻璃,主要是由金属杂质含量高和气泡等级低造成的;羟基含量不是影响石英玻璃本征损耗的主要因素;表面损耗是石英玻璃器件振动能量损耗的主要来源之一,可以通过湿法刻蚀消除。     

配电网单相接地故障检测技术分析

在整个电力系统中,在单相接地方面发生的故障就占据了配电网故障整体的绝大部分,而电力系统本身的安全性以及可靠性,基本上只取决于电力系统结构中中性点的实际工作方式。而在我国,电压处于6kv到35kv的中电压系统普遍采用中性点不进行接地处理的不接地系统,本文就实际分析,对各种接线方法之间差异性进行了较为详细的比较研究。     

Synthesis and photoluminescence properties of novel red-emitting Ca14Mg2(SiO4)8:Eu3+/Sm3+ phosphors

Novel red-emitting Eu3+, Sm3+ singly doped and co-doped Ca14Mg2(SiO4)8 phosphors were prepared by conventional solid- state reaction. Powder X-ray diffraction patterns were employed to confirm phase pu...     

机械手喷号机在CSP生产线上的应用

针对邯钢CSP线的特点,为适应生产的需要,CSP生产线引进了机械手喷号机。文中主要介绍了机械手喷号机的结构原理、应用过程和应用效果。     

CSP连铸机结晶器振动台的维护与改造

介绍了邯钢CSP连铸机结晶器振动台振动机构的原理及特性,针对振动台设计的不足,对振动台振动液压缸的位置传感器内置形式及扇形段锁紧夹安装布置进行了改造及优化,为连铸机振动台的设计、改造,取得了较好效果.     

Luminescent properties of blue long-lasting phosphorescence phosphors Sr6Al18Si2O37：Eu2＋,RE3＋

A series of novel blue long-lasting phosphorescence phosphors Sr6A118Si2037：Eu^2＋,RE^3＋ （RE3＋=Ho^3＋, Gd^3＋, Dy^3＋ and Pr^3＋） were prepared by the conventional high-temperature solid-state reaction in a reductive atmosphere. Their properties were systemati- cally investigated utilizing X-ray diffraction （XRD）, photoluminescence, phosphorescence and thermoluminescence （TL） spectra. The phosphors emitted blue light that was related to the emission of E~＋ due to 5d-4f transition. Bright blue long-lasting phosphorescence （LLP） could be observed after the excitation source was switched off. For the optimized sample, the blue long-lasting phosphores- cence could last for nearly 4 h in the light perception of the dark-adapted human eye （0.32 mcd/m2）. The effects of RE3＋ ions on phosphorescence properties of the phosphors were studied, and the results showed that the co-doping of RE^3＋ ions greatly enhanced the intensity of the peak around 315 K which was related to the long lasting phosphorescence of the phosphors at room temperature and consequently improved the performance of the blue phosphorescence such as intensity and persistent time.     

Luminescence properties of a new yellow long-lasting phosphorescence phosphor NaAlSiO_4:Eu~(2+),Ho~(3+)

A new aluminosilicate long-lasting phosphor with composition of NaAlSiO4:Eu2+,Ho3+ was synthesized and investigated. Under UV light excitation, the phosphor emitted yellow light corresponding to the characteristic emission of Eu2+ due to 5d-4f transition. Bright yellow phosphorescence sustaining for more than 30 min was observed after ceasing the excitation. The phosphorescence intensity decay obeyed a t–1 decay law, indicating a tunneling electron-hole recombination process in the phosphor. Four peaks appeared in the thermoluminescence curve and the ones at 322 and 370 K were thought to account for the long lasting phosphorescence at room temperature. The Ho3+ ion incorporated into the phosphor did not give any light but dramatically increased the intensities of both photoluminescence and phosphorescence via promoting defect levels in the phosphor.