Estimation and Optimization of the Principal H-Maser Parameters

The scale along the coordinate axes in the equations of motion hitherto used for an H-maser (in relative units) is shown to depend on Q as the quality factor for an H-maser. This hinders both analysis of the operation of the H-maser and optimization of its parameters. The modified equations of motion proposed here do not have that shortcoming. We determine the atomic flux into the bulb that gives the H-maser the best metrological characteristics.     

Signal Integrity: Fault Modeling and Testing in High-Speed SoCs

As we approach 100 nm technology the interconnect issues are becoming one of the main concerns in the testing of gigahertz system-on-chips. Voltage distortion (noise) and delay violations (skew) contribute to the signal integrity loss and ultimately functional error, performance degradation and reliability problems. In this paper, we first define a model for integrity faults on the high-speed interconnects. Then, we present a BIST-based test methodology that includes two special cells to detect and measure noise and skew occurring on the interconnects of the gigahertz system-on-chips. Using an inexpensive test architecture the integrity information accumulated by these special cells can be scanned out for final test and reliability analysis.     

金属换热器选用经济分析

本文以系统节能和提高综合经济效益的观点，分析了金属换热器传热系数的影响因素及提高途径；气流阻力与动力消耗；传热面积与投资的定量关系。为正确选用不同结构金属换热器及其性能提供了依据。     

像增强型夜视系统的图像信息传递

在分析了像增强夜视系统信息传递的基础上，指出像增强器输出端荧光屏至人眼的图像传递过程，构成了像增强夜视系统信息传递量的限制．提出了采用系统信息传递量作为夜视系统设计与评价的方法，利用这种方法可以发现在像增强器增益足以补偿光谱选道衰减的条件下，采用彩色像增强可以大幅度增加夜视系统传输的信息量．     

Biodegradation of monoaromatic hydrocarbons in aquifer columns amended with hydrogen peroxide and nitrate

The ability of indigenous microorganisms to degrade benzene, toluene, ethylbenzene and xylenes (BTEX) in laboratory scale flow-through aquifer columns was tested separately with hydrogen peroxide (110 mg/l) and nitrate (330 mg/l as NO₃⁻) amendments to air-saturated influent nutrient solution. The continuous removal of individual components from all columns relative to the sterile controls provided evidence for biodegradation. In the presence of hydrogen peroxide, the indigeneous microorganisms degraded benzene and toluene (> 95%), meta- plus para-xylene (80%) and ortho-xylene (70%). Nitrate addition resulted in 90% removal of toluene and 25% removal of ortho-xylene. However, benzene, ethylbenzene, meta- and para-xylene concentrations were not significantly reduced after 42 days of operation. Following this experiment, low dissolved oxygen (< 1 mg/l) conditions were initiated with the nitrate-amended column influent in order to mimic contaminated groundwater conditions distal from a nutrient injection well. Toluene continued to be effectively degraded (> 90%), and more than 25% of the benzene, 40% of the ethylbenzene, 50% of the meta- plus para-xylenes and 60% of the ortho-xylene were removed after several months of operation.     

Modeling of Diffusion in Capillary Porous Materials During the Drying Process

This paper presents a model of heterogenous diffusion in capillary porous materials during the process of drying. The governing heat and mass transfer equations have been established using the liquid as well as vapor flow. Two models have been presented. Model 1 does not consider the heat conduction while the model 2 has been established by considering the conduction. The developed models and the numerical solutions of the resulting differential equations can take into account the moisture and temperature dependent thermophysical properties of the product. All equations have been established in spherical coordinates but the programme written for the purpose of calculations can be used for other geometries also. Numerical calculations have been performed for gas concrete and tiles using model 1, while model 2 has been used for gas concrete only because of the lack of data for thermophysical properties of the tile. For gas concrete it was seen that conduction has only marginal effect on the drying process and the numerical predictions of the drying process were reasonably accurate.     

氢电弧等离子体法制备的纳米镍铈粒子的催化特性

利用氢电弧等离子法制备具有储氢特性纳米镍铈粒子，并在气相苯加氢反应中研究了其催化特性，发现其催化活性与储氢特性及表面层中ＮｉＣｅ合金存在有关，且具有高的选择性和热稳定性，这与纳米粒子独特的结构及铈的加入有关。     

工艺因素对金属封装外引线弯曲疲劳的影响

考察了金属封装外壳制造工艺对外引线弯曲疲劳的影响,发现电镀镍是导致外引线弯曲次数明显减少的最主要工艺步骤,且随镀镍层厚度的增加,弯曲次数减少。此外还讨论了外引线的氢含量和晶粒度对引线抗疲劳能力的影响。     

化肥厂合成气及重整氢真空变压吸附制取高纯度氢气

从设计、生产操作和经济效益3个方面阐述了以化肥厂合成气及重氢为原料，通过真空变压吸附（VPSA）装置制取高纯度氢的过程。工业应用结果表明，该制氢工艺是一项操作简便灵活，制氢费用较低的工艺路线。VPSA装置技术和设计上的特点能够保证大的操作弹性、高的产品氢纯度和较高的氢气回收率。在36％－51％的低限负荷下，通过适当调整吸附时间，可获得纯度99％的氢气产品，89％－92％的氢气回收率。     

Skeletal Isomerization and Inter—molecular Hydrogen Transfer Reactions in Catalytic Cracking

Bimolecular hydrogen transfer and skeletal isomerization the important secondary reac-tions among catalytic cracking reactions,which affect product yield distribution and product quality,Catalyst properties and operating parameters have great impact on bimolecular hydrogen transfer and skeletal isomerization reactions .Bimolecular hydrogen transfer activity and skeletal isomrization activity of USY-containing catalysts are higher thn that of ZSM-5-containing catalyst.Coke deposition on the active sites of catalyst may suppress bimolecular hydrogen transfer activity and skeletal isomer-ization activity of catlys in different degrees.Short raction time causes a decrease of hydrogen trans-fer reaction,but and increase of skeletal isomerization reaction compared to cracking reaction in catalytic cracking process.