淀积条件对GDa—SiNx薄膜电学特性的影响

本文讨论了用辉光放电法制备氮化硅薄膜时衬底温度、射频功率和气体流量比对薄膜的电导率、介电常数和击穿强度的影响。通过优化生长条件，制备了优质非晶氮化硅薄膜，其介电常数为７．５、击穿强度为５．５ＭＶ／ｃｍ、电导率为１０－１３（Ωｃｍ）－１。     

单光子时间分辨在线谱仪系统中的接口电路

本文介绍单光子时间分辨在线谱仪系统中的多道分析器与IBM PC/XT微型计算机接口的工作原理及控制程序。     

石油系油浆与煤系闪蒸油的焦化性能——I．热解条件的影响

通过偏光显微镜观察了石油系油浆（LH）与煤系闪蒸油（SN）焦化后所得焦块的光学结构。结果表明，在较宽条件下两种原料单独焦化均得不到取向度高的流线型结构。将两种原料以一定比例混合后先热解丙焦化所得焦块的光学结构明显好于二者混合后直接焦化所得焦块的光学结构，其中LH和SN以3：2的重量比混合后在440℃、1MPa下热解3．5h然后再在530℃、1MPa下焦化8h所得焦块为具有较高取向度的流线型结构，适合于作为针状焦的起始原料。     

Flammability and thermal stability studies of ABS/Montmorillonite nanocomposite

Acrylonitrile–butadiene–styrene (ABS)/montmorillonite nanocomposites have been prepared using a direct melt intercalation technique by blending ABS and organophilic clay of two different particle sizes: OMTa (5 µm) and OMTb (38 µm). Their structure and flammability properties were characterized by X‐ray diffraction, high resolution electronic microscopy (HREM), thermogravimetric analysis (TGA) and cone calorimeter experiments. The results of HREM showed that ABS/5 wt% OMTa nanocomposite was a kind of intercalated–delaminated structure, while ABS/5 wt% OMTb nanocomposite was mainly an intercalated structure. The nanocomposites showed a lower heat release rate peak and higher thermal stability than the original ABS by TGA and cone calorimeter experiments. Also, the intercalated nanocomposite was more effective than an exfoliated–intercalated nanocomposite in fire retardancy. Copyright © 2003 Society of Chemical Industry     

MOS RF reliability subject to dynamic voltage stress-modeling and analysis

Dynamic stress on MOSFETs with 900-MHz inverter-like waveforms as well as static (or dc) stress were evaluated experimentally. It showed that the degradation due to dynamic stress is less than that of dc stress for our test transistors. A compact model is used to evaluate the degradation in radio frequency performances, such as transconductance, cutoff frequency, linearity, and noise figure. A class-AB power amplifier is presented as an example to demonstrate the effect of dynamic stress on RF circuit performance.     

Response of simulated propellant and explosives to projectile impact—II. Fragmentation

This paper is the second of a series concerned with the penetration and perforation phenomena in two types of propellant and explosive simulant, named Propergol, due to the impact at normal incidence of both blunt and conically-tipped steel strikers. The collision results in fragmentation, plug formation and generation of a cloud of debris that includes particles of measurable dimensions traveling with significant velocities. Both the fragment size and area as well as the ejecta mass are determined experimentally as a function of Propergol specimen thickness and impact velocity or energy. The cumulative number of fragments as a function of size for the Propergol is uniformly found to be a bi-linear semi-logarithmic relationship with the bifurcation occurring at the mean crystal radius. Individual crystals and the crater generated are examined by means of a scanning electron microscope.

A phenomenological model of the fragmentation process is constructed, based on an assumed spherical shape of the fragments and the bi-linear fragment distribution, using energy methods. This is combined with a perforation analysis that considers the process to be sequentially composed of initial indentation, fragmentation, and sliding and deflection of the Propergol disks. An evaluation of this model providing fragment volumes as a function of impact velocity is compared with experimental results and found to be in good agreement.     

艰难兴大业踏雪寻梅来——访香港著名企业家沈家燊

序：“为什么我的眼里常含泪水，因为我对这土地爱的深沉。”每次读到艾青的这句诗，我都攀不住在想诗人到底有着怎样的情节．而这情节又是怎棒化成澎湃的激情？当面对沈家柴先生那闪烁着光芒，自信、执着、激情四射的眼神时，我缝于找到了答案：正是对一个国家、一座城市拥有了不移信念、不倦热情、不衰挚爱，他才有了面对错综复杂矛盾时的坦荡胸怀，才会有了风雨兼程的无怨无悔。沈家集为这句诗做出了最生动的逄释，他以自己的方式在津洁大地上刻写着人生的价值，他将心和力奉献给了天津。     

A Shortcut Method for Estimating the HETP of Structured Packed Distillation Columns at Elevated Pressure

A shortcut model is developed for predicting the HETP of a structured packed distillation column operating at elevated pressure. The proposed model incorporates the geometrical parameters of the packing, physical properties of the vapor and liquid phases, and the hydrodynamics of the two‐phase flow. The proposed model is tested and validated by comparing the predicted results with the present experimental data and some published HETP data. The results show that the proposed model can predict the experimental data with a deviation smaller than 20 %.     

CFD Simulation of Liquid Film Flow on Inclined Plates

A two‐phase flow CFD model using the volume of fluid (VOF) method is presented for predicting the hydrodynamics of falling film flow on inclined plates, corresponding to the surface texture of structured packing. Using the proposed CFD model the influence of the solid surface microstructure, liquid properties and gas flow rate on the flow behavior was investigated. From the simulated results it was shown that under the condition of no gas flow the liquid flow patterns are dependent on the microstructure of the plates, and proper microstructuring of the solid surface will improve the formation of a continuous liquid film. It was also found that liquid properties, especially surface tension, play an important role in determining the thin‐film pattern. However, there are very different liquid film patterns under the action of gas flow. Thinner liquid films break easily, but thicker liquid films can remain continuous even at higher gas flow rates, which demonstrates that all factors affecting the liquid film thickness will affect the liquid film patterns under conditions of counter‐current two‐phase flow.     

Ultrasonic thin-walled tube wave structure for sensing devices

Theoretical and experimental investigations of thin-walled tube acoustic wave devices for gravimetric sensing applications are presented. Integrated sensor configurations have been demonstrated by employing a sol-gel processed thin piezoelectric lead zirconate titanate (PZT) film. This was coated coaxially on stainless steel tubes and interdigital transducers (IDT) fabricated as the transmitter and receiver on the curved tube surfaces. We have observed tube waves along both the axial and circumferential directions between 1 and 6.6 MHz. We have also analyzed the mass sensitivities of different modes propagating along the tubes and shown that high mass sensitivity can be achieved by keeping the tube wall thin