Mechanical Model on Brittle Crack Initiation and Propagation

A mechanical model is presented in this paper to describe the initiating and propagating of brittle cracks. Two criteria have been deduced from the model to determine the effects of such factors as local stress state, surface and grain boundary energies as well as local grain boundary orientation on the initiating and propagating of both intergranular and transgranular brittle cracks. By which the role of adding B in Ni3Al base alloys to improve their ductility,temper and hydrogen embrittlements in steels and other alloys as well as the random feature of brittle crack initiation could be explained     

Position-sensitive superheated-liquid-droplet neutron dosimeter

The one-dimensional (1D) position-sensitive superheated-liquid-droplet dosimeter (SLDD) has been fabricated and tested in the laboratory. The 1D SLDD is fabricated from a 9.525-mm OD, 6.35-mm ID, 20-cm long, Plexiglas-walled tube filled with a mixture of superheated-liquid Freon droplets and host medium glycerol. Washer-shaped piezoelectric acoustic transducers are positioned at both ends of the tube; they determine the number and positions of the acoustic events when the superheated-liquid droplets evaporate upon neutron irradiation. The SLDD is irradiated with the ¹³⁷Cs and ⁶⁰Co γ-sources, as well as ²⁵²Cf neutron source to test for its radiation response and spatial resolution. The SLDD based on the Freon-134a superheated-liquid droplets operating at 20°C and 1 atm is found to be ideal for measuring absorbed neutron dose. This study also proves that the positions of the radiation-induced nucleation acoustic events can be linearly determined from the differences in the transmission times received by the acoustic transducers on the 1D SLDD. The spatial resolution of the neutron depth-dose is 1 mm due the finite response time (1 μs) of the piezoelectric acoustic transducers.     

Cd-ZSM-5沸石催化剂的制备、表征和芳构化催化性能

采用离子交换、浸渍和混合三种方法制备镉改性ZSM-5沸石催化剂,考察了改性方法和镉含量对催化剂的表面酸性和Cd状态以及芳构化性能的影响。结果表明,加入镉降低了B酸性,Cd~(2+)与沸石结合形成了L_(1612)酸中心,其生成量取决于改性方法和Cd含量,并与芳构化活性提高有直接关系。     

非线性干涉滤光片开关特性及逻辑功能

应用干涉滤光片作为一种光学双稳器件,演示了光学逻辑开关功能。     

APPLICATION OF COMPUTER NUMERICAL METHOD IN PORE STRUCTURE CALCULATION

This paper compares the results Of calculat-ing pore structure and graphing differential and integralpore size distribution by hand and Computer,and presents thatlagrangian interpolation uesd by calculating pore structure issuitable and reliable.     

乘累加运算器的高性能解决方案

在设计数字信号处理器时我们经常要设计高性能的乘累加运算器，文章详细分析了乘累加运算器的结构，提出了其高性能设计方案并采用标准单元进行了实现，同时提出了DCT运算单元的高性能解决方案。     

LDD方法在提高电路工作电压中的应用研究

研究了利用轻掺杂漏结构来制作高电源电压器件的工艺方法。分析了ＬＤＤ结构参数对器件击穿特性的影响，并结合实验结果对Ｎ＾－区的注入剂量，长度及引入的串联电阻进行了优化设计。     

NMOS器件两次沟道注入杂质分布和阈电压计算

分别考虑了深浅两次沟道区注入杂质在氧化扩散过程中对表面浓度的贡献。对两次注入杂质的扩散分别提取了扩散系数的氧化增强系数、氧化衰减系数和有效杂地系数，给出了表面浓度与工艺参数之间的模拟关系式，以峰值浓度为强反型条件计算了开启电压，文章还给出了开启电压、氧化条件、不同注入组合之间的关系式。     

地面油管漏失定量测试方法探讨

对油管漏失进行定量测试的方法确定具体漏失位置。方法运用双频道回声探仪探测动液面的原理和工作方法，根据油管漏失形成的死油坏在测试曲线上出现特殊波位置判断油管漏失位置。结果：经过７０多井次的现场试验，该方法具有较高的准确性和可靠性。结论：利用特殊波可以有效监测油管漏失，并具有推广使用价值。     

深亚微米MOSFET衬底电流的模拟与分析

利用器件模拟手段对深亚微米ＭＯＳＦＥＴ的衬底电流进行了研究和分析，给出了有效的道长度，栅氧厚度，源漏结深，衬底掺杂浓度以及电源电压对深亚微米ＭＯＳＦＥＴ衬底电流的影响，发现电源电压对深亚微米ＭＯＳＦＥＴ的衬底电流有着强烈的影响，热载流子效应随电源电压的降低而迅速减小，当电源电压降低到一定程度时，热载流子效应不再成为影响深亚微米ＭＯＳ电路可靠性的主要问题。