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通风设计的最终目的,是要不确地选出矿井主要通风机.主要通风机选得是否适当对全矿井的安全生产及其技术经济效果有着长期的影响.通风机的风压是选择主通风机的重要参数,因此,通风机风压计算是否正确,乃是主通风机选型的关键因素之一.通风设计中有关通风机风压的计算,方法很不一致.究其原因,是对于矿井通风动 相似文献
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<正> 《煤矿安全》1982年第5期国外安全技术栏“长独头巷道的通风方法”一文,读后使人颇感我国煤矿掘进通风很有借鉴的价值。根据波兰《格洛基茨》矿井掘进603号平巷采用局扇并联加辅助伸缩风筒(见图1,Φ=0.6m,辅助风筒长度L_1=280m,总长度 L 约800m)的经验表明:能提高长独头巷道的供风量(见表1),促进安全生产,减 相似文献
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Spectral shifts and spectral intensities of partially coherent chirped Airy pulsed(PCCAP) beams propagating through oceanic turbulence are studied, where spectral properties of partially coherent chirped Gaussian pulsed(PCCGP) beams are also compared. The effects of optical parameters and oceanic turbulence parameters on spectral shifts at different observation positions are mainly discussed. It is shown that the spectral shift of PCCAP beam is richer than that of PCCGP beam, and there exists some critical positions for PCCAP beams where the spectral red-shift reaches its maximum. The spectral red-shift increases with increasing chirped parameter, correlation length or decreasing pulse duration. However, the increasing of spectral red-shift is accompanied by increasing dissipation rate of turbulence kinetic energy in unit mass liquid or decreasing relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. A physical explanation of rapid spectral transition is also made. 相似文献
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