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861.
862.
Simon L. Axelsen Alan Shapiro Evgeni Fedorovich Han van Dop 《Environmental Fluid Mechanics》2010,10(4):387-414
An analytical model for katabatic flow induced by cold strip of finite width in the cross-slope direction but of infinite
extent in the downslope direction is presented. The fluid is assumed to have a constant (eddy) viscosity, and the Coriolis
force is neglected. A numerical simulation has been used to verify the model, which is shown to revert to the classical Prandtl
model if the strip width goes to infinity. The effects of the strip width and slope angle on the katabatic flow are studied.
The buoyancy and downslope velocity reach maximum values at the centre of the strip, and spread outwards in the cross-slope
direction. The downslope wind maximum weakens for narrow strips and shallow slopes. In contrast to the Prandtl solution, which
shows a counter flow above the wind maximum, our model predicts the counter flow to occur outside the strip. The cross-slope
variation in the surface forcing induces cross-slope and slope-normal velocities, which are manifested in vortices at the
strip edges. Below the wind maximum, the fluid above the cooling surface descends and moves toward the strip edge where it
is detrained from the strip region. Replenishment of fluid into the strip region takes place above the wind maximum. 相似文献
863.
零价铁还原降解活性染料 总被引:17,自引:0,他引:17
在分别通氮气,不通氮气和曝气的情况下,在水溶液中用零价铁还原降解活性染料。实验发现:在不同的氛围中,活性染料的降解程度不同,其降解程度为:暴气〉不通氮气〉通氮气。在不同通氮 和曝气的条件下,活性染料的降解过程中有黄色絮状沉淀生成,经红外光谱鉴定为三聚氯氰的取代产物。 相似文献
864.
本文通过对江西省吉水县坡地资源现状、特点的分析,从未利用坡地、利用不充分坡地、利用不合理坡地3方面对吉水县坡地资源进行了潜力分析,并提出了开发利用坡地资源的途径 相似文献
865.
Hu Liu Theodore G. Cleveland Keh Han Wang 《Journal of the American Water Resources Association》1999,35(1):167-176
ABSTRACT: One hundred and sixty-two rainfall-induced soil erosion tests were conducted to assist in predicting soil loss and subsequent increase in total suspended solids leaving a highway construction site during a rainfall event. A rainfall simulator and a water flume were constructed for the tests. Soil shear strength, compressive strength, rainfall intensity, and soil bed slope were treated as variables during the experiments. The soil with a higher shear strength resisted soil erosion better than lower strength soils. Soil loss was nearly independent of shear strength at low rainfall intensity but at high intensities, the shear strength was more important in resisting soil loss. Lower soil loss can be expected for cohesive soils if the compressive strength is high. 相似文献
866.
867.
868.
Advanced reburning (AR) is effective for nitrogen oxides (NOx) reduction, which integrates the basic reburning (BR) with the injection of nitrogen agents and additive compounds. The basic reburning of poplar, cornstalk, wheat-straw and peanut shell, is studied on a boiler simulator facility (BSF). The influence of operating parameters and the synergistic effect of the injection of ammonia, urea or/and sodium carbonate on NOx reduction are investigated. The results show that an efficiency of 54–67% NOx reduction could be achieved during the basic reburning process under the optimum operating conditions and the efficiency would be increased if nitrogen agent is injected with the over-fire air or into the burnout zone. Further, co-injection of sodium carbonate with the nitrogen agent could make the NOx reduction process more thorough. On the whole, 85–92% NOx reduction could be achieved during the advanced reburning process with a reburning fuel heat input of 15–20%. 相似文献
869.
本文首先概论了纤维(织物)阻燃技术,其次重点讨论了两种含磷本质阻燃PA纤维,一种是由含磷羟基羧酸或含磷二元羧酸与己二胺及己二酸共缩聚而后纺丝制得.另一种是用螺环磷酰氯与PA66及PA6纤维反应制得,后者具膨胀性。最后是综述了纤维(织物)阻燃技术的最新进展,包括新型表面改性技术及纳米技术等。 相似文献
870.
韩笑 《中国个体防护装备》2010,(1):6-6
<正>美国劳工部职业安全与卫生管理局近日发布了G/TBT/N/USA/216/Add.1号补遗。该局拟修订现行危险信息标准,以符合联合国全球化学品统一分类及标签系统,相信修订提案能够改善向雇主和雇员提供的关于化学危 相似文献