基于STL格式的三维重建技术

基于STL格式的三维重建是目前反求工程中研究的重要范畴，它是一个多学科交叉的研究领域，是计算机图形学、计算机可视化和图像处理在工程技术中的重要应用．现有的三维重建技术大致可分为两类：基于表面的方法和基于体元的方法．但对于存在凹环和分支等复杂轮廓的情况，重建结果很不理想．所以有必要在他们的基础上进一步研究较优的重建算法．     

Synthesis and structures of two novel indolo[3,2-b] carbazole derivatives

Indolocarbazole derivatives have already been reported to be good organic semiconductor candidates. The knowledge of the relationship between the structure and packing of molecules in crystal is indispensable in design of high performance organic semiconductor materials. Two new indolocarbazole derivatives, 2,8-dibromo-5,11-di-[4-(isoindole-1,3-dione-2-yl)butyl]indolo[3,2-b]carbazole (I) and 2,8,6,12-tetrabromo-5,11-di-(4-chlorobutyl)indolo[3,2-b]carbazole (II) have been synthesized and the crystal structures have been studied. The dichloromethane solvate of (I), C₄₂H₃₂Br₂N₄O₄ · 2CH₂Cl₂, is monoclinic, space groups P2₁/n. Unit cell parameters are a = 11.6847(2), b = 12.6942(2), c = 13.7899(2) Å, β = 91.8220(10)°. Unlike other indolo[3,2-b]carbazole derivatives, there is no any π–π stacking between the indolocarbazole backbone of two adjacent molecules in the crystal. Since the isoindole-1,3-dione-2-yl is introduced in 5- and 11-positions in the molecule, the intermolecular short contacts mainly localize in between the pendant groups of the neighboring indolocarbazole molecules. The compound (II) is also monoclinic with P2₁/c space groups. Unit cell parameters are a = 4.6427(9), b = 11.425(2), c = 24.511(4) Å, β = 93.47(1)°. In contrast with compound (I), the molecules of (II) possess strong face-to-face π–π stacking. The crystal structures were studied in detail. It is concluded that linear pedant groups benefit to co-facial π–π interaction. Additionally, the molecule electronic spectra were studied by quantum chemistry theoretical calculation.     

非水体系中甲醇在粗糙铂电极上解离吸附的表面增强拉曼 光谱研究

利用共焦显微拉曼系统和表面增强拉曼散射(SERS)效应研究了非水体系中甲醇在粗糙铂电极上的解离吸附过程。结果表明：甲醇在粗糙铂电极上解离吸附后产生了毒性中间物CO,在较负的电位区间内,H与CO共吸附于电极表面并影响CO的吸附行为,随电位正移,ν~P~t~-~C的变化可以用电化学Stark效应进行解释,而ν~C~~O的变化则是由于电化学Stark效应和CO偶极耦合的共同作用所引起的。     

激光打孔对氮化铝绝缘性能的影响

氮化铝陶瓷具有优良的绝缘和导热性能,是传导冷却超导电力装置绝缘与导热连接件的首选,激光切割是对其进行加工的最有效方法,但激光切割可能对其绝缘性能产生影响,进而影响超导电力装置的安全运行。基于此,通过对激光打孔前后氮化铝基片孔周区域绝缘电阻的测量、金相结构和扫描电镜成分的比较,分析了激光打孔对氮化铝绝缘性能的影响,并总结了选用氮化铝基片作为超导电力装置电流引线的绝缘与导热垫片应注意的问题。     

基于周期极化KTiOPO4晶体的高亮度纠缠源研制

量子纠缠是量子信息领域的核心资源,目前利用β型硼酸钡(BBO)晶体参量下转换制备的纠缠光子对的亮度较低,它直接制约了量子通信的最远距离,已无法满足星地实用化量子通信的发展需求.利用周期极化KTiOPO4晶体,采用准相位匹配技术设计产生了一种后选择的纠缠源,测得的符合计数达到了16×103s-1 mW-1,极化对比度达到27∶1,在亮度上比基于BBO的量子纠缠光源提高了一个数量级以上.这一高亮度的纠缠源可以广泛应用于量子密钥分发、量子隐形传态以及量子计算等新兴量子信息领域,为实现全球化量子通信提供了有力的保障.     

An improved boundary element-free method （IBEFM） for two-dimensional potential problems

The interpolating moving least-squares (IMLS) method is discussed first in this paper. And the formulae of the IMLS method obtained by Lancaster are revised. Then on the basis of the boundary element-free method (BEFM), combining the boundary integral equation (BIE) method with the IMLS method, the improved boundary element-free method (IBEFM) for two-dimensional potential problems is presented, and the corresponding formulae of the IBEFM are obtained. In the BEFM, boundary conditions are applied directly, but the shape function in the MLS does not satisfy the property of the Kronecker δ function. This is a problem of the BEFM, and must be solved theoretically. In the IMLS method, when the shape function satisfies the property of the Kronecker δ function, then the boundary conditions, in the meshless method based on the IMLS method, can be applied directly. Then the IBEFM, based on the IMLS method, is a direct meshless boundary integral equation method in which the basic unknown quantity is the real solution of the nodal variables, and the boundary conditions can be applied directly and easily, thus it gives a greater computational precision. Some numerical examples are presented to demonstrate the method.     

Monte Carlo方法研究低能电子束曝光沉积能分布规律

建立一个描述低能电子在多元多层介质中散射的物理模型,运用MonteCarlo方法模拟低能电子在靶体胶衬底中的复杂散射过程,在此基础上通过大量计算研究入射束能、胶层厚度、衬底材料等不同曝光条件对抗蚀剂沉积能密度分布的影响,获得沉积能分布规律:适量的低束能、薄胶层、低原子序数衬底可以使前散射电子对胶中沉积能密度分布的贡献增大、背散射电子的贡献减小,从而提高曝光分辨率. 关键词： 电子束曝光 MonteCarlo方法 低能电子散射 能量沉积     

我国核电站人－机－环境的安全性及失误的预防

本文从人－机－环境的有机性、系统性出发，以我国核电站建设与运行的实践，以大量事例阐明了我国核电的安全原理与目标，分析了选址的安全性，强调了“粉Ｃ设计、精心施工”，“安全第一、质量第一”方针的贯彻，论证了高质量人员培训、严格的操作规程，这些是预防人因失误、保证核电站安全的关键．     

离子交换富集-导数火焰原子吸收法测定自来水中Cu,Fe和Zn

本文研究了用 2 0 1× 7阳离子交换树脂对自来水中的微量元素进行交换富集 ,采用微量脉冲进样 导数火焰原子吸收法测定富集后溶液中的Cu ,Fe和Zn ,该方法灵敏度分别为 0 2 9,0 5 9和 0 0 6 μg·L- 1 ,精密度分别为 4 2 8% ,1 95 %和 2 2 8% ,检测限分别为 1 2 8,5 85和 0 6 8μg·L- 1 ,回收率分别为 91 13% ,10 1 34%和99 84 % ,本方法大大减少了需样量 ,简便快速 ,灵敏度高。