Study of 18-cm long single-sided AC-coupled silicon microstripdetectors

The SSC GEM silicon Central Tracker design incorporated 18-cm long single-sided AC-coupled silicon microstrip ladders. Compared to the 12-cm long ladders considered in the preliminary stages of the tracker design, the 18-cm long ladders have the advantage of reduced cost, channel count and overall power consumption, and led to a simplified tracker assembly. However, such long ships also present the challenge of maintaining satisfactory performance. The increased capacitance and series resistance contribute to lower signal-to-noise ratios, longer time walk, higher power consumption per channel and increased probability of crosstalk to neighboring channels. In this paper, an accurate method to calculate the geometric capacitance of the AC-coupled microstrips is presented and the calculated results are compared with measurements, SPICE simulations are performed to predict the noise, the extent of interstrip capacitive coupling and the dispersion of the detector signal due to the finite series resistance of the metal strips and the long length of the detector. The influence of the preamplifier current and the shaping time on the signal and noise levels is also presented. The study concludes that the 18-cm long ladders can successfully satisfy the performance goals of the GEM silicon Central Tracker     

Dexamethasone perfusion of the labyrinth plus intravenous dexamethasone for Ménière's disease

Recent clinical and laboratory evidence indicates that Meniere's disease is an immune-mediated disease. Dexamethasone perfusion of the inner ear through the round window plus intravenous dexamethasone often will stop the dizzy spells, reduce the fullness and low-frequency tinnitus, and sometimes improve the hearing in patients with Meniere's disease. The dexamethasone must act mostly on the endolymphatic sac and, to a lesser extent, on the stria vascularis and spiral ligament, the known targets of immune response in the inner ear, to reduce the endolymphatic hydrops and restore the fluid dynamics of the endolymph. Despite the good results with streptomycin perfusion, the number of patients with further hearing loss is large, so dexamethasone perfusion with intravenous dexamethasone should be tried first. The initial response to dexamethasone perfusion plus intravenous dexamethasone has been very good, with very little risk of further hearing loss, and it holds great promise for the future.     

Ethnic differences in the length of the menstrual cycle during the postmenarcheal period

In 1989, 125 African-American and 123 European-American girls aged 12-14 years were enrolled in a 2-year study in which they maintained a menstrual calendar, recording the date and amount of menstrual bleeding. Weight, exercise, and stress during the previous week were recorded at the start of each menstrual cycle. Although only minor ethnic differences were observed in expected cycle length (29.3 vs. 28.8 days for European-American and African-American girls, respectively), more prominent differences were observed in the between-subjects standard deviation of cycle length (2.9 vs. 2.2 days, respectively) and in the odds of having a cycle longer than 45 days (odds ratio=1.86, 95% confidence interval 1.17-2.97) for European-American compared with African-American girls. Low weight for height and high levels of exercise increased the probability of having a cycle longer than 45 days and decreased expected cycle length of 13- to 45-day cycles. Additional investigation of potential ethnic differences in menstrual cycle characteristics is warranted.     

在酸性介质中N-H伪酸Mannich反应机理的量子化学研究

用量子化学中的ＳＣＦ－ＭＯＡＭ１方法，全优化计算了以苯并唑酮为伪酸组分的（Ｎ－Ｈ酸）Ｍａｎｎｉｃｈ反应的反应物、过渡态和产物络合物的分子几何构型、电子结构和生成热。根据计算所得各反应的活化能，提出了该反应在酸性介质中的机理，即甲醛首先与苯并唑酮作用，其产物再与二甲胺作用生成Ｍａｎｎｉｃｈ碱，并就其缘由进行了讨论。     

聚合物复合材料填充剂的改性

在前人研究的基础之上，归纳总结了聚合物复合材料填充剂的种类，综述了对其进行表面改性的目的、条件、方法、工艺以及对改性结果的表征等。文章还分析了影响填充聚合物复合材料性能的因素，指出了今后发展的方向。     

一种多径环境下基于四阶累积量的阵列扩展测向方法

本文分析了基于四阶累积量的测向方法不能正确测量多径信号方向的原因，提出了一种多径环境下的基于四阶累积量的新型测向方法。该方法利用零点领处理方法抑制多径信号，然后采用四阶累积量进行阵列扩展测向。计算机模拟结果表明该方法在多径环境下具有良好的性能并且可能实现对足够多的信号进行测向。     

广播发射集散控制系统

本文介绍了广播发射台利用计算机技术、网络技术、遥控遥测技术、现代测试手段，对设备进行自动化控制与管理；实现设备技术指标自动测试，发射台无人值班、有人留守，建立机器的计算机档案制度，确保安全优质播出的方法和经验。     

Sequential discrete multilevel automated system for recording electron-diffraction patterns

This article considers a discrete sequential multilevel automated system for recording electron-diffraction patterns. A comparative analysis is presented, along with experimental results that make it possible to evaluate the effectiveness of the technical decisions on which the device is based. The general design of the system is presented. Translated from Izmeritel'naya Tekhnika No. 5, pp. 16–18, May, 1996.     

前轮毂旋转弯曲疲劳断裂分析

采用化学分析，金相检验，力学性能测试及扫描电镜分析方法对轿车前轮毂早期断裂原因进行了分析。结果表明，冷却不足使组织中出现网状及小块状铁素体，导致硬度偏低，加之磨削加工痕迹较粗是引起前轮毂早期断裂的原因。