大电流监测信号提取的光收发及信号处理

近年来,大电流的监测成了人们十分关心的问题,这是由于大电流有强磁、高压、电流大等一系列的直接监测所不能克服的问题。这就需要把高压大电流的强电信号,经过提取后变成能在实验室中直接观测的弱电信号。为此,如何从高压大电流的信号中提取出随实时信号变化而实时变化的小信号就变成了一个关键问题。详细介绍了监测信号提取的光收发电路原理和后续信号处理电路,分析了各部分的作用,给出了必要的分析结果。     

Formation of low-resistivity poly-Si and SiNx films by Cat-CVD for ULSI application

In this paper, bulk-Si metal–oxide–semiconductor field effect transistors (MOSFETs) are fabricated using the catalytic chemical vapor deposition (Cat-CVD) method as an alternative technology to the conventional high-temperature thermal chemical vapor deposition. Particularly, formation of low-resistivity phosphorus (P)-doped poly-Si films is attempted by using Cat-CVD-deposited amorphous silicon (a-Si) films and successive rapid thermal annealing (RTA) of them. Even after RTA processes, neither peeling nor bubbling are observed, since hydrogen contents in Cat-CVD a-Si films can be as low as 1.1%. Both the crystallization and low resistivity of 0.004 Ω·cm are realized by RTA at 1000 °C for only 5 s. It is also revealed that Cat-CVD SiN_x films prepared at 250 °C show excellent oxidation resistance, when the thickness of films is larger than approximately 10 nm for wet O₂ oxidation at 1100 °C. It is found that the thickness required to stop oxygen penetration is equivalent to that for thermal CVD SiN_x prepared at 750 °C. Finally, complementary MOSFETs (CMOSs) of single-crystalline Si were fabricated by using Cat-CVD poly-Si for gate electrodes and SiN_x films for masks of local oxidation of silicon (LOCOS). At 3.3 V operation, less than 1.0 pA μm⁻¹ of OFF leakage current and ON/OFF ratio of 10⁷–10⁸ are realized, i.e. the devices can operate similarly to conventional thermal CVD process.     

高功率双工旋转场移相器

旋转场移相器具有移相精度高(均方根误差可小于1°)和温度稳定性好等特点,通过改进射频传输结构,可大大提高他的功率容量。利用旋转场移相器的互易特性和铁氧体圆极化器的非互易特性,设计出高功率双工旋转场移相器。其双工特性可将收/发信号分开,实现移相器和环行器的双重功能,用于天线的收发通道等场合时,可省去一个高功率环行器,结构紧凑。分析了双工旋转场移相器的工作原理,阐述了高功率应用下的设计方法,推导出了管状铁氧体的相移量计算公式,按此方法设计了实用的器件,并给出了试验数据。     

Phase equilibria of quasi-binary systems consisting of multicomponent polymers 1 and 2. IV: Poly(ethylene oxide)/poly(propylene oxide) systems

To confirm the reliability of the theory of phase equibria of multicomponent polymer 1/multicomponent polymer 2 systems (i.e. quasi-binary systems) and the method of computer experiment based on this theory (Brit. Polym. J., 23 (1990)285; 23 (1990)299; Polym. Int., 29 (1992)219), could point curves (CPC), two-phase volume ratios ( R ) and critical solution points (CSP) have been determined experimentally for the quasi-binary mixtures of poly(ethylene oxide) (M¯_w = 647, M¯_w/M¯_n = 1.15; M¯_w and M¯_n, the weight-average and numberaverage molecular weights, respectively) and poly(propylene oxide) (M¯_w = 2028, M¯_w/M¯_n = 1.08; and M_w = 2987, M_w/M_n = 1.13). The hydroxyl end groups of both polymers were methoxylated in advance by the Cooper & Booth method (Polymer, 18 (1977)164). The thermodynamic interaction parameter between both polymers, χ₁₂, and the concentration dependence parameters for the above quasi-binary systems were determined by the method proposed in a previous paper (Brit. Polym. J., 23 (1990)299). CPC, R and CSP values calculated on the basis of the theory are in good agreement with the values determined experimentally.     

锆钡镧铝氟化物玻璃的分相研究

本文综述了氟化物玻璃中的分相研究。在前人研究基础上应用透射电镜，X射线能谱，电子能量损失谱及X射线衍射，差热分析等研究了锆钡镧铝氟化物玻璃中的液-液分相，发现此种现象普遍存在于该类玻璃之中。对玻璃成分与分相形貌及微观结构之间的关系、对析出晶相种类及分相与析晶的相互影响进行了研究。提出欲降低氟化物玻璃的光损耗，分相与析晶一样是不容忽视的因素。     

不用专门相移装置的三维面形测量

提出一种不需要专用相移装置实现相移，主要利用数字图像处理技术实现三维面形测量的方法，研究结果表明，用原干涉图像及1幅以上的移值条纹图主可能实现物体三维面形的测量。     

Experimental investigation of the normal spectral emissivity and other thermophysical properties of pulse-heated Ni-Ti and Au-Ni alloys into the liquid phase

1. Introduction Metal working industry needs accurate thermo- physical properties of liquid metals and alloys as input data for different simulation routines to im- prove the performance of their products. Within this paper we continue the systematic investigation of the dependence of emissivity of binary alloys on the relative concentration of the constituent elements (for a previous paper see [1]). 2. Experimental method A fast ohmic pulse heating technique is applied to heat metallic wire-s…     

Phase Composition of Oxide Scales during Reheating in Hot Rolling of Low Carbon Steel

Low carbon steel was oxidized over the temperature range 1000‐1250°C in O₂‐CO₂‐H₂O‐N₂, O₂‐H₂O‐N₂, and O₂‐CO₂‐N₂ gas mixtures. Oxidation times were 12‐120 min. and the scales were 50‐2000 μm thick. The variations of these parameters were chosen to elucidate the phase composition of oxide scales under conditions similar to those of reheating furnaces in hot strip mills, using either thin slab casting or conventional casting and rolling technology. Two types of scales have been observed which are influenced by the furnace atmosphere, oxidation time, and temperature. The first type is a crystalline scale with an irregular outer surface, composed mostly of wustite (FeO), and a negligible amount of magnetite (Fe₃O₄). The second type is the classical three‐layer scale, composed of wustite (FeO), magnetite (Fe₃O₄), and hematite (Fe₂O₃). In general, the experiments showed that an increase in oxidation time decreased the percentage of wustite while the percentages of magnetite and hematite increased. A rise in oxygen concentration in the gas mixture increased the percentages of magnetite and hematite, confirming earlier experimental findings. In water vapour‐free atmospheres O₂‐CO₂‐N₂, the oxide scales had a low percentage of wustite, and high percentage of magnetite and hematite. Carbon dioxide showed a small influence at 1100°C, and a negligible one at 1250°C.