Millimeter-wave asymmetric Fabry-Perot modulators

We have designed, fabricated, and characterized GaAs-AlGaAs (λ=864 nm) asymmetric Fabry-Perot modulators with ≈37 GHz modulation frequency response, comparable to the fastest waveguide modulators. The modulation response saturates at high optical powers due to saturation of the excitonic absorption and heating effects, but the frequency response is independent of the incident optical intensity, since it depends only on the RC time constant, and not on the carrier transit time. The device design takes advantage of the fact that the quantum-confined Stark effect is more pronounced at some distance from the absorption edge to achieve a modulator with ⩾20 dB contrast and ≈3 dB insertion loss for ±2 V operating voltage, but only 21 fF capacitance. The DC bias used to move the operating point off the absorption edge has the additional benefits of improving the linearity and chirp of the device, as well as the saturation intensity. Here we present measurements of the modulation and photocurrent responses of the modulators, calculate the RC and transit times for the device, analyze the saturation mechanisms, and discuss the linearity and chirp of the device from the perspective of a high-speed digital optical communications system     

冶金能源信息库管理与能耗分析系统的研究

研究了通过计算机建立冶金能源信息库管理与能耗分析系统的相关问题。     

Molecular forces between membranes displaying neutral glycosphingolipids: evidence for carbohydrate attraction

The surface force apparatus was used to determine the fundamental forces governing the adhesion between mixed bilayer membranes comprising lactosyl ceramide (LacCer) and di-tridecanoyl-phosphatidyl choline. Forces between membranes were quantified as a function of the glycolipid surface densities, which ranged from 0 to 30 mol %. Control measurements of the forces between pure phosphatidylcholine membranes and mixed bilayers of lactosyl ceramide with phosphocholine showed that the steric thickness of the carbohydrate headgroups increased from 19 to 25 A when the glycolipid density increased from 10 to 20 mol %. The layer compressibility also decreased with increasing carbohydrate coverage, but the corresponding adhesion between lactosyl ceramide-containing membranes increased with increasing amounts of glycosphingolipid in them. The nonspecific van der Waals forces accounted for the attraction measured in the control experiments and that between identical 10 mol % LacCer bilayers. However, the increase in the adhesion with increasing glycolipid density was 2-4 times greater than predicted by Lifschitz theory. Additionally, the forces measured during separation of membranes containing 20 and 30 mol % glycosphingolipid indicated that the headgroups bind and rearrange during bilayer detachment. The interactions between the carbohydrates are weak and apparently dynamic, and they generate an additional density-dependent intermembrane attraction that is on the order of the van der Waals force.     

开发计算机管理信息系统推动设备供应管理现代化

本文介绍了我国冶金大型钢铁联合企业设备供应管理系统计算机应用开发过程及研制方法，并分析了取得的经济效益和在国内的推广价值。     

多路红外防盗报警器

介绍一种利用热释红外线传感器探头作为探测器的多路防盗报警器.该报警器能够自动完成交直流供电转换,具有灵敏度高、电压适用范围宽、准确可靠等特点,并配有多种声光报警方式.给出了该报警器的基本原理和方框图。     

Calculation of the energy loss of fast multicharged ions in solids

The application of a classical approach to the energy loss calculation for fast multicharged ions in solids provides energy losses or kinetic energy electrons and for inner shell holes separately. The calculated total energy losses differ from the tabulated data by less than 20%.     

Guaranteeing the skill level of specialists in the nuclear industry under conditions of the restructuring and dissolution of the USSR

Abstracts of report.     

SiH4＋CH4激光等离子体动力学时空特性

采用时间，空间分辨的等离子体光辐射诊断技术，研究了脉冲ＴＥＡＣＯ２激光诱发ＳｉＨ４＋ＣＨ４击穿产生的等离子体膨胀过程，得到不同空间位置，不同实验条件下等离子体发光的时间特性，证明了ＳｉＨ４＋ＣＨ４气体击穿产生爆燃波而后诱发激波是等离子体中基本宏观动力学过程，并在实验上分析了激波对等离体内化学反应的影响，为激光等离子体合成ＳｉＣ粉末微观反应动力学过程的研究提供了参考数据。