Formation of lanthanum beryllate real structure under different crystallization conditions

The aim of this paper is to characterize the major structural defects of lanthanum beryllate single crystals grown by the Czochralski method, including those doped with rare-earth elements, and to reveal their relationship to specific properties of the crystal structure of La₂Be₂O₅ and with their crystallization conditions. As a basic method for research, we used transmission X-ray topography. It was established that the defect state of La₂Be₂O₅ crystals prepared by this method can be caused by different types of dislocations and their ordered assemblies, solid-phase inclusions of crucible metal and eutectically co-crystallizing phases, as well as by face growth sectors with elevated content of dopant. We show a possibility for growing single crystals of doped lanthanum beryllate having a minimum quantity of structural defects that could be suitable for manufacture of high quality laser rods.     

低能X射线吸收法测量泡沫材料密度

文章介绍为适应惯性约束聚变(ICF)靶材料研究而发展的一种密度测量方法。通过测量X射线经靶材料吸收前后的强度变化,可较为精确地计算出待测样品的密度。用于泡沫材料密度测量的X射线源是特制的激发源。     

Sm-EDTMP稳定常数的测定及其在血浆模型中的平衡组分

为了解153 Sm EDTMP 在血液中的平衡组分,采用电位滴定法测定了 EDTMP 的质子化常数和 Sm EDTMP的稳定常数。EDTMP的质子化常数为:lgβ2 =22.69±0.02,lgβ3 =30.54±0.03,lgβ4 =36.93±0.02,lgβ5=42.15±0.01,lgβ6 =45.02±0.03,lgβ7 =46.14±0.02;Sm EDTMP的稳定常数为: lg KSmL=22.62±0.02,lg KSmLH=29.93±0.02,lg KSmLH2 =36.18±0.03。在生理pH条件下,EDTMP主要以LH3 形式存在, Sm EDTMP 主要以 SmLH 形式存在。血浆模型中,在生理 pH 条件下, Sm 主要以带负电荷的SmLH和SmL形式存在,Sm EDTMP通过人体肾脏排泄;在低 pH(pH<6)条件下,以 Sm 柠檬酸组分存在,表明153Sm EDTMP在人体中肝摄取很低。同时,平衡组分中游离 Sm3+ 含量很低,说明 Sm EDTMP有很高的血浆稳定性,不用加入过量配体来防止标记物解离。EDTMP在血浆模型中主要以 LH3 形式存在,没有出现EDTMP的钙配合物组分,说明配体EDTMP不会使患者血钙明显降低。     

Preparation and photoluminescence of surface N-doped ZnO nanocrystal

ZnO nanoparticles doped with nitrogen on surface were prepared by calcinating pure ZnO nanoparticles at 550 and 600 °C in NH₃ atmosphere. Uniform N-doped ZnO nanocrystal was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and XPS. A Strong violet photoluminescence (PL) at 400nm was observed at room temperature when excited with 300 nm light, and the emission peak increases with the increase of nitrogen atoms concentration. The violet PL originated from the electron transition from shallow donor levels of oxygen vacancies and doping nitrogen atoms to the top of valence band level.     

基于图像测量技术的装配间隙在线测量研究

装配间隙的在线检测是产品装配时经常遇到的问题,其测量精度应在0.02 mm以内。介绍了一种基于图像测量技术的在线测量方案,将间隙通过光学系统在CCD摄像机中成的像经由图像采集卡采集后送交图像测量软件处理和分析,由测量软件给出结果,并对该方案的测量误差做了分析。实验结果表明:测量误差在0.015mm以内,满足装配需要。     

高流速下钯上氢氘的排代研究

在钯氘化物上进行了高流速下氢氘的排代实验。结果表明，氘的排代效率随排代时间的增大而增加；与低压、低流速相比，高流速下排代压力的增加部分弥补了流速增大对氢氘交换速率的影响，因此仍可以得到较高的氘回收率。     

Expansion of Plasma of Electrically Exploding Single Copper Wire Under 4.5kA～9.5kA/Wire

Abstract The experimental system for electrically exploding single metal wire has been de-signed and manufactured. Expansion of the dense plasma column formed from an electricallyexploding Cu wire of diameter 30 μm has been studied with a high-speed photographer to obtainthe time-dependent radius (R-t) curve. The experimental results demonstrate that the mean ex-pansion rate of the dense plasma column is 1.94 μm/ns, 2.6 μm/ns and 3.75 μm/ns according tothe peak pulse current 4.5 kA, 7 kA and 9.5 kA respectively. The results can be beneficial to givinga profound understanding of the early stage of wire-array Z-pinch physics and to improvement ontheir design.     

固态继电器在加热器中的应用设计

介绍了固态继电器(SSR)的基本原理,以SSR为核心,采用定时器、单片机和PID调节器等控制SSR的方法进行了定时开关控制器、程控烘箱和玻璃退火炉的调功加热设计。简要分析了SSR的热设计,并讨论了在SSR的应用过程中影响其性能可靠性的相关因素以及抗干扰问题。     

应用GM（1,1）模型研究高压脉冲电容器的长期贮存寿命

根据高压脉冲电容器电容量变化缓慢、实验数据较少等特点,使用GM(1,1)模型及残差修正GM(1,1)模型分别对其电容量的变化进行了预测,与实际测试值相比具有较高的精度。并使用基本GM(1,1)模型对该电容器的寿命进行了估计和分析。     

深次临界装置α本征值l算方法比较研究

编制了用3种方法独立计算a本征值的计算程序,并分析了深次临界情况下a本征值计算遇到困难的原因。计算结果表明:改进的直接法计算范围宽、精度高,是解决深次临界情况下a本征值计算困难的有效途径。