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991.
通过对总变电站6k V系统备用电源自动投入装置误动作进行分析,指出存在的缺陷,提出相应的改进措施,试验及现场运行表明这些措施是可靠有效的。 相似文献
992.
993.
介绍功能主义设计和设计硬点的思想,提出以功能驱动的硬点结构设计方法,并通过此方法对进气系统的结构设计进行分析。着重分析空气滤清器在客车上的布置和进气系统管路的设计,得到相应的设计准则和设计硬点,为进气系统设计提供了思路方法和理论依据。 相似文献
994.
The conductivity mechanism for a carbon black (CB) filled high-density polyethylene (HDPE) compound was investigated in this work. From the experimental results obtained, it can be seen that the relation between electrical current density (J) and applied voltage across the sample (V) coincides with Simmons's equation (i.e., the electrical resistivity of the compound decreases with the applied voltage, especially at the critical voltage). The minimum electrical resistivity occurs near the glass transition temperature (Tg) of HDPE (198 K). It can be concluded that electron tunneling is an important mechanism and a dominant transport process in the HDPE/CB composite. A new model of carbon black dispersion in the matrix was established, and the resistivity was calculated by using percolation and quantum mechanical theories. © 1996 John Wiley & Sons, Inc. 相似文献
995.
Kuo-Ming Luo 《Propellants, Explosives, Pyrotechnics》1996,21(4):206-214
The kinetic parameter of energetic materials with four components, i.e. lead thiocyanate, antimony sulfide, potassium chlorate, and trinitrotoluene, (PSKT), was analyzed with differential thermal analysis (DTA) technique. Kinetic parameter equations were derived for estimating a general nth-order decomposition reaction from a single DTA curve. Three categories, for n < 1, n = 1, and n ≠ 1 were derived. Three kinetic parameters, namely, activation energy E, reaction order n, and pre-exponential factor A can be calculated directly without any iteration from the characteristic temperatures To, Til, Tm, and Te that are the decomposition starting point, first inflection point, peak maximum point and end point on the DTA curve, respectively. The stability and compatibility of PSKT energetic material can be judged from experimental characteristic temperatures and calculated kinetic parameters. The effect factors of characteristic temperature and kinetic parameters were evaluated by means of Yates' algorithm. 相似文献
996.
997.
Minli Wei Jia Li Huili Yan Tao Luo Jiang Huang Yangyang Yuan Liaoliao Hu Liping Zheng 《International journal of molecular sciences》2022,23(1)
Post-translational modifications (PTMs) have been confirmed to be involved in multiple female reproductive events, but their role in physiological ovarian aging is far from elucidated. In this study, mice aged 3, 12 or 17 months (3M, 12M, 17M) were selected as physiological ovarian aging models. The expression of female reproductive function-related genes, the global profiles of PTMs, and the level of histone modifications and related regulatory enzymes were examined during physiological ovarian aging in the mice by quantitative real-time PCR and western blot, respectively. The results showed that the global protein expression of Kbhb (lysineβ-hydroxybutyryllysine), Khib (lysine 2-hydroxyisobutyryllysine), Kglu (lysineglutaryllysine), Kmal (lysinemalonyllysine), Ksucc (lysinesuccinyllysine), Kcr (lysinecrotonyllysine), Kbu (lysinebutyryllysine), Kpr (lysinepropionyllysine), SUMO1 (SUMO1 modification), ub (ubiquitination), P-Typ (phosphorylation), and 3-nitro-Tyr (nitro-tyrosine) increased significantly as mice aged. Moreover, the modification level of Kme2 (lysinedi-methyllysine) and Kac (lysineacetyllysine) was the highest in the 3M mice and the lowest in 12M mice. In addition, only trimethylation of histone lysine was up-regulated progressively and significantly with increasing age (p < 0.001), H4 ubiquitination was obviously higher in the 12M and 17M mice than 3M (p < 0.001), whereas the modification of Kpr (lysinepropionylation) and O-GlcNA in 17M was significantly decreased compared with the level in 3M mice (p < 0.05, p < 0.01). Furthermore, the expression levels of the TIP60, P300, PRDM9, KMT5B, and KMT5C genes encoding PTM regulators were up-regulated in 17M compared to 3M female mice (p < 0.05). These findings indicate that altered related regulatory enzymes and PTMs are associated with physiological ovarian aging in mice, which is expected to provide useful insights for the delay of ovarian aging and the diagnosis and treatment of female infertility. 相似文献
998.
圆锥壳-折板结构在航空舱体装备结构中十分常见,作为航空装备重大核心精密科学仪器设备的承载体,舱体结构强度设计问题尤为关键.本文以圆锥壳-折板结构为对象,对其动力学特性展开分析.通过仿真计算,得到圆锥壳-折板结构在随机振动下的响应结果,并且建立材料参数与动力学响应之间的响应面函数.进一步利用Spearman秩相关系数,进行灵敏度分析,筛选出圆锥壳与折板结构中影响舱体结构动强度的主要因素.最后得到各个主要因素对于响应面动力学响应的影响规律曲线. 相似文献
999.
The drilling operation in the roof bolting process,especially in hard rock,generates excessive respirable coal and quartz dusts,which could expose the roof bolt... 相似文献