德摩根一致代数的度量化

我们给出了德摩根一致代数可伪度量化的一个充分必要条件。     

Uniformity in radon exhalation from construction materials using can technique

The uniformity in radon exhalation rates for 46 tiles of granite, marble and ceramic used as construction materials were determined using “Can Technique” employing CR-39 nuclear track detectors (NTDs). On each tile, two sealed cans, each enclosing one NTD fixed at the center of the tile surface area covered by the can, were mounted at two different locations of each individual tiles. The track production rates on the NTDs representing radon exhalation rates were measured. The radon exhalation rates from the surface of individual tiles showed uniform exhalations within the calculated uncertainties of the measured values. This makes Can Technique an alternative simple method to measure radon exhalation rates. Calibration required to convert track production rates into radon exhalation rates for the used can and NTD was done using an active technique. The correlation between the measurements by the two techniques shows a good linear correlation coefficient (0.83).     

SiH_4－O_2体系LPCVD SiO_2薄膜的工艺及其应用

本文研究了ＳｉＨ４—Ｏ２体系ＬＰＣＶＤＳｉＯ２的工艺及设备。为了得到厚度均匀性好的薄膜，改进了反应气体的进气方式和装片舟的结构，获得了每炉１００片、直径为１００ｍｍ的硅片的膜厚不均匀性≤士５％的结果。     

Sampling and metrology

The result of a measurement refers in principle only to the amount of substance actually contributing to the analytical signal. However, an appropriate definition of the measurand must include a specification of the system for which the result of the measurement should apply. All systems being inherently heterogeneous, representativity assumes importance for the metrological quality of a measurement, and the process needed to ascertain representativity is sampling. The contribution from this characteristic must be included when expressing the uncertainty of the reported value of the measurand. Representative sampling of systems that are infinite or non-uniform was developed by Pierre Gy in his Theory of Sampling. Finite systems can achieve uniformity by mechanical treatment and mixing; the heterogeneity of these systems can be characterized by a sampling constant, expressed in units of weight, for each particular species being determined. Examples of the contribution of sampling to the uncertainty of analytical results are discussed for some biological materials. Presented at the 2nd International Conference on Metrology – Trends and Applications in Calibration and Testing Laboratories, November 4–6, 2003, Eilat, Israel.     

基于大功率LED扩展光源的均匀光斑光辐射模拟器设计

基于边缘光线原理和光学扩展量守恒思想,结合复合抛物面聚光器和轴对称自由曲面透镜,设计并研制了大功率发光二极管扩展光源的反射/折射准直器.运用Tracepro软件对系统进行光束追迹模拟仿真和实验,研制出均匀光斑的光辐射模拟器.模拟器输出发散角为±12°光束,测量距离出射面50cm处光屏的光斑,在尺寸为14cm×14cm的光照范围内,测得光斑水平方向中心线上的光度均匀度优于4.1%,竖直方向中心线上的光度均匀度优于3.8%.     

多边形棒状透镜出端辐射均匀性的研究

研究了用多角形棒状透镜产生高均匀性正方形和圆形照明的最佳结构参量.结果表明,对于正方形棒状透镜,输出端的照明均匀性随透镜的长度振荡变化,在某些特定长度达到极小值.对于圆形照明面积,比较了从三角到八角的六种多边形.利用三角形积分透镜可以获得最佳的照明均匀性,但光能利用率相对较低,六角形积分透镜可同时获得较高的照明均匀性和光能利用率.     

LPCVD制备二氧化硅薄膜工艺研究

采用TEOS源LPCVD法制备了SiO2薄膜,采用膜厚仪对薄膜的厚度进行测试.通过不同条件下SiO2薄膜的厚度变化,讨论了TEOS源温度、反应压力及反应温度等工艺条件对淀积速率和均匀性的影响.结果表明,在40℃,50 Pa左右,淀积速率随TEOS源温度、反应压力基本呈线性增大.通过多次试验改进,提出了SiO2膜淀积的典...     

钨化学气相淀积工艺方块电阻均匀性的研究

钨化学气相淀积因为其在接触孔/通孔填充中出色的台阶覆盖能力而在半导体工业中被广泛应用,在量产中经常会出现监控片的方块电阻均匀性超规格。本文主要研究了加热器、气体输送、氟化铝、机械传片定位、真空微漏等因素对方块电阻均匀性的影响,特别周期性等离子清洗产生的氟化铝对晶圆边缘的抑制反应是影响腔体维护频率的主要原因,并提出改善均匀性的有效办法。     

声源分布和超声频率对清洗声场均匀性的优化*

驻波和换能器指向性等影响声场均匀性,造成清洗死角,影响清洗效果。采用COMSOL仿真软件建立了单个换能器位于底部的三维模型,通过染色法实验结果验证模型的有效性。研究了换能器同时位于底部和侧面、多排换能器位于底部时的声场,用声压幅值相对标准差来量化均匀性,发现该两种换能器分布方式能够有效优化声场均匀性。通过调节频率研究频率对声场的影响,进一步优化声场均匀性。对声源分布的确定、频率的选择以满足声场均匀化需求有指导意义。     

Design of thermal imprinting system with uniform residual thickness

A new thermal imprinting system for the printed circuit boards (PCBs) with both large areas and fine conducting lines was developed adopting hot airs with a high pressure. Several small nickel stamps were used to cover the large area, and the stamps were replicated from an electroforming process, in addition, a vacuum jig was utilized to avoid bubbles captured in resins or imprinted interfaces. Stefan’s equation was used to estimate residual thicknesses of the imprinted resins, and effects of imprinting conditions on the residual thickness were investigated from numerical analyses to confirm process profiles and specifications of the developed equipment. The results show that the developed imprinting system can remarkably improve the uniformity of the residual thickness after imprinting, as compared with those of the conventional press, in spite of the thickness difference between the used stamps.