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31.
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对广铁集团范围内的铁路电力系统受灾情况进行了现场调研.通过对受灾资料归纳总结,对雪灾引起铁路供电系统停电故障的原因进行了分析,对铁路供电系统应对雪灾等自然灾害的措施进行了探讨. 相似文献
33.
在飞行模拟器中实现雪的实时模拟 总被引:6,自引:0,他引:6
基于粒子系统和空气动力学效应对下雪这一自然现象进行了实时仿真,建立了一个风的模型,把雪的运动看作风的运动和雪的自由落体的综合运动。根据雪粒子的自然属性和飞行模拟实际的视景需求,简化了数学计算,模拟了下雪这一特殊气象。最后对粒子间的碰撞做了简要介绍。 相似文献
34.
Jouni Pulliainen 《Remote sensing of environment》2006,101(2):257-269
The monitoring of snow water equivalent (SWE) and snow depth (SD) in boreal forests is investigated by applying space-borne microwave radiometer data and synoptic snow depth observations. A novel assimilation technique based on (forward) modelling of observed brightness temperatures as a function of snow pack characteristics is introduced. The assimilation technique is a Bayesian approach that weighs the space-borne data and the reference field on SD interpolated from discrete synoptic observations with their estimated statistical accuracy. The results obtained using SSM/I and AMSR-E data for northern Eurasia and Finland indicate that the employment of space-borne data using the assimilation technique improves the SD and SWE retrieval accuracy when compared with the use of values interpolated from synoptic observations. Moreover, the assimilation technique is shown to reduce systematic SWE/SD estimation errors evident in the inversion of space-borne radiometer data. 相似文献
35.
导电混凝土除冰化雪系统输入功率的有限元计算 总被引:7,自引:0,他引:7
用有限元程序成功地分析了导电混凝土除冰化雪系统.通过对除冰时的分析,验证了方法的正确性,同时得到了除冰时间与输入功率的关系,进而确定了除冰时所需的最小功率.通过对除雪时的分析,得到了经济合理的除雪方式及最小输入功率,为导电混凝土的制作和该系统的工程应用提供了坚实的理论基础. 相似文献
36.
Alexander Tesar Jozef Melcer 《International journal for numerical methods in engineering》2007,69(7):1446-1459
Dynamic identification and optimization of bionics shell roofs subjected to the snow skidding is dealt with in present paper. The optimization control of structural geometry in order to induce the aimed snow skidding with reduction of dead weight snow loads is aimed. Theoretical, numerical and experimental in situ assessments based on wave approaches of the problem are presented. Structural application in situ on attractive shell roof made of laminated wood with optimization control suggested is presented. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
37.
2008年冰雪灾害造成广西电力设施大面积损坏,分析其原因,指出供输电线路重冰区导线局部应力大于导线瞬时破坏应力,是造成大范围断线倒杆的原因。以实例简介了供电线路大电流融冰技术。通过灾后反思,提出了重新建立和完善分层次电网、分层次电源、国防后备电源的建议。 相似文献
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Xiaoning Lei Weiwei Li Jianjiang Lu Yanbin Tong Shanman Li 《Water and Environment Journal》2015,29(2):252-258
Polycyclic aromatic hydrocarbon (PAH) in snow samples collected from Mount Nanshan (Xinjiang, China) was investigated for eight stations. Fourteen PAHs were detected in these samples. The total PAH concentration ranged from 70.15 ng/L to 155.67 ng/L, with an average of 113.02 ng/L. Human carcinogens, such as fluoranthene, chrysene, benzo(a)pyrene, dibenzo(a,h)anthracene, indeno(1,2,3‐cd)pyrene and benzo(ghi)perylene in snow were assessed based on risk quotient. Preliminary assessment showed that these PAHs posed a moderate risk. Component analysis showed that the PAHs found in the snow samples were mainly three‐ring PAHs, which comprised 34.51–90.81% of the total PAHs. Phenanthrene, fluorene and anthracene accounted for 35.08, 11.90 and 11.13% of the total PAHs, respectively. The ΣPAH content increased with the increasing altitude, and the highest concentration of 155.67 ng/L was observed in snow samples from the N7 station, which was located near the top of the mountain. This high PAH concentration in N7 was possibly due to more frequent human activities in the area and long‐distance transportation of PAHs. Isomer ratios were used to determine the possible sources of PAHs in the samples. The results indicate that coal and biomass combustion made a larger contribution than emissions from petroleum consumption. It is therefore of utmost importance to develop new fuels taking the place of coal and to achieve as complete as possible for the burning of carbon‐containing materials. 相似文献