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171.
针对某转膛自动机身管衬套定位键断裂的问题,通过分析其工作原理和断裂表现,并考虑到转膛体衬套、身管以及炮箱对身管衬套的影响,给出身管衬套定位键断裂的原因。在对身管衬套进行一定简化与假设的基础上,建立身管衬套的三维模型,采用有限元分析方法计算身管衬套的强度,找出需加强的薄弱部分并对身管衬套的结构进行修改,再进行有限元分析。对比理论分析与试验,结果表明修改后的身管衬套可满足要求。 相似文献
172.
173.
为检验发射药的撞击强度,建立了一种新型的模拟实验装置,用来模拟发射药在自动武器或火炮膛内高温、高压的发射环境,计算分析了实验装置的膛压和影响发射药速度的因素,得出了具有一定价值的结论。 相似文献
174.
175.
The origin of magnetoconductance (MC) in organic light-emitting diodes under bipolar injection conditions was investigated using devices containing pristine Super-Yellow poly(phenylene vinylene) (SY-PPV) or SY-PPV:phenyl-C61-butyric acid methyl ester (PCBM) (x wt%) blends as the active layers. In pristine SY-PPV device, it was found that the low-field component of MC was always larger than the high-field component. Additionally, the low-field component increased and then saturated with increasing the electrical stressing time, whereas the high-field component remained unchanged. These behaviors were analyzed using empirical formula (containing a Lorentzian and a non-Lorentzian function), which suggested that the dominant mechanism in the MC response was hyperfine mixing between single and triplet polaron pairs that occurred on trap sites. The specific role of these traps, providing interaction sites for hyperfine mixing, was confirmed by controlling the lifetime of the trapped polaron-pairs states by doping the active layer with PCBM. 相似文献
176.
177.
Evidence is presented that two competing failure mechanisms exist in the Si-SiO2 system with one mechanism dominating at low dose rates and the other at high. Much lower dose failures than expected were
discovered at low dose rates (<0.1 rad(Si)/s) and very low dose rates (∼0.001 rad(Si)/s) in commercial SGS 4007 CMOS devices.
These failure doses plotted versus dose rate have a bell-shaped curve, rather than the expected straight line (decreasing
with increasing dose rate), indicating that a different failure mechanism is dominant at low dose rates than at high. 相似文献
178.
R. A. B. Devine 《Journal of Electronic Materials》1990,19(11):1299-1301
It is demonstrated that the results of refractive index, infra-red absorption and electron spin resonance measurements on
low temperature PECVD silicon dioxide films are con-sistent with a network structure composed of densified, amorphous SiO2 and micro-scopes. The density of the amorphous SiO2 is suggested to be greater than that of un-densified SiO2 by about 10%. Approximately 5% of the deposited film volume is argued to consist of micropores High temperature annealing
relaxes the dense state of the amorphous SiO2 and collapses the volume occupied by the micropores. 相似文献
179.
180.
The defects induced by inductively coupled plasma reactive ion etching (ICP-RIE) on a Si-doped gallium nitride (GaN:Si) surface have been analyzed. According to the capacitance analysis, the interfacial states density after the ICP-etching process may be higher than 5.4 × 1012 eV−1 cm−2, compared to around 1.5 × 1011 eV−1 cm−2 of non-ICP-treated samples. After the ICP-etching process, three kinds of interfacial states density are observed and characterized at different annealing parameters. After the annealing process, the ICP-induced defects could be reduced more than one order of magnitude in both N2 and H2 ambient. The H2 ambient shows a better behavior in removing ICP-induced defects at a temperature around 500 °C, and the interfacial states density around 2.2 × 1011 eV−1 cm−2can be achieved. At a temperature higher than 600 °C, the N2 ambient provides a much more stable interfacial states behavior than the H2 ambient. 相似文献