共查询到20条相似文献,搜索用时 109 毫秒
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介绍了定向爆破拆除复杂环境下45m高砖烟囱工程实例。通过适当地提高爆破切口高度,并采取加固爆破切口以下的烟囱壁等措施,解决了无烟囱倒塌足够长度和烟囱后坐的技术问题。同时选择了合理的爆破参数和有效的安全防护措施,使爆破取得了圆满成功。 相似文献
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介绍了用定向爆破拆除复杂环境下结构体破损的砖烟囱.为防止烟囱在爆破时发生后座和散架,确保烟囱在倒塌过程中不发生偏移,根据烟囱的周围环境和结构特点,选择了合理的爆破切口长度,对破损的支撑体部分采取了加固措施,对爆破切口采用对称微差爆破,取得了良好的爆破效果. 相似文献
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Keshavarz MH Motamedoshariati H Pouretedal HR Tehrani MK Semnani A 《Journal of hazardous materials》2007,145(1-2):109-112
A new method is described to predict shock sensitivity of C(a)H(b)N(c)O(d) explosives without using any experimental data. It can determine shock sensitivity based on small-scale gap test as the pressure required to initiate material pressed to 90%, 95% and 98% of theoretical maximum density. Three essential parameters would be needed in the new scheme which contain a+b/2-d, the existence of alpha-C-H linkage in nitroaromatic compounds or NNO(2) functional group and difference of the number of amino and nitro groups attached to aromatic ring. Predicted shock sensitivities in some well-known explosives have a root mean square (rms) deviation of 3.97, 4.02 and 5.89kbar of experiment to initiate pressure of material pressed to 90%, 95% and 98% of theoretical maximum density, respectively. 相似文献
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Guo H Chen J Li X Zhuang S 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(9):1834-1843
By the Riemann method, a coupled wave model is derived for the ordinary-to-ordinary (OO) and extraordinary-to-extraordinary (EE) Bragg diffraction of a Gaussian beam by overlapping holographic gratings in a uniaxial crystal. The computer simulation is used to discuss the relations among the diffraction efficiency, the index modulation, the wavelength sensitivity, the angular sensitivity, and the the widths of the recording and reading beams. The characteristics of EE and OO diffraction in a uniaxial crystal are found to be remarkably different. The simulation shows that EE diffraction may exhibit far higher diffraction efficiency than does OO diffraction for very low index modulation with the same hologram size, for example, nearly 90% when the size is 8.2 x 10(-5). 相似文献
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Shock compaction of silicon carbide powder 总被引:1,自引:0,他引:1
Ken-Ichi Kondo Sinji Soga Akira Sawaoka Masatada Araki 《Journal of Materials Science》1985,20(3):1033-1048
A series of shock compaction experiments on SiC powder were carried out over a wide range of shock pressures and shock temperatures up to 30 GPa and 3400 K. Large changes in some physical properties and a variety of unique microstructures were observed in the shock-treated samples with changes in impact conditions. For an iron plate impactor, the optimum impact condition, which depends on the initial density, is 2.5 km sec–1 for 70% initial density and 2.0 km sec–1 for 50%. The best-sintered compact of SiC with 97% density and micro-Vicker's hardness of 2700 kg mm–2 was obtained under optimum conditions. Good compacts with high relative density and high strength exhibit the disruptive effects of the shock wave, which are indicated by microstrain increase and crystallite size reduction. The skin model is presented here in order to estimate the heterogeneous shock state which is realized under and after shock loading of the initial powder aggregates. 相似文献
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为研究乳化炸药储存稳定性及其破乳机理,通过乳胶基质储存试验,采用显微照相法观测乳化炸药储存过程中乳状液的变化,采用甲醛还原法测定乳胶基质析晶量随时间的变化,并对硝酸铵的结晶进行理论分析。结果表明,乳化剂是影响乳化炸药储存稳定性的关键因素,提出了炸药乳状液破乳机理;析晶量随时间的关系也表明乳化剂是影响乳胶基质存储稳定性的重要因素。认为使用高分子乳化剂增强油膜厚度和抑制硝酸铵析晶是提高乳化炸药稳定性的有效方法,同时将研究结果与工业生产实际相结合,对得到的结论进行了检验。通过本文的研究,达到了深入认识影响乳化炸药储存稳定性的因素以及破乳机理的目的。 相似文献
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Flexible mechanosensors with a high sensitivity and fast response speed may advance the wearable and implantable applications of healthcare devices,such as real-time heart rate,pulse,and respiration monitoring.In this paper,we introduce a novel flexible electronic eardrum (EE) based on single-walled carbon nanotubes,polyethylene,and polydimethylsiloxane with micro-structured pyramid arrays.The EE device shows a high sensitivity,high signal-to-noise ratio (approximately 55 dB),and fast response time (76.9 μs) in detecting and recording sound within a frequency domain of 20-13,000 Hz.The mechanism for sound detection is investigated and the sensitivity is determined using the micro-structure,thickness,and strain state.We also demonstrated that the device is able to distinguish human voices.This unprecedented performance of the flexible electronic eardrum has implications for many applications such as implantable acoustical bioelectronics and personal voice recognition. 相似文献