常温袋除尘在电石炉除尘工程的研究与应用

新华结晶硅有限公司2×10 000kVA电石炉除尘项目是一项污染治理项目,该项目结合内蒙古当地的气象条件,利用较少的投资,解决了困扰多年的电石炉烟尘污染问题,同时回收的粉尘又有较高的利用价值,取得了较好的经济效益.     

小型露天采石场爆破作业安全评价方法的探讨

应用安全检查表、事故树、作业条件危险性分析等方法对露天小型采石场爆破作业进行了分析评价,找出了导致爆破作业事故发生的可能因素及可采用的预防途径,为小型露天爆破作业事故的预防提供有益参考.     

溶解乙炔站爆炸半径估算及防火、防爆措施

介绍了国内溶解乙炔的生产工艺流程,对溶解乙炔站可能引起的火灾、爆炸原因进行了分析,估算生产过程中乙炔的爆炸半径.根据爆炸半径,提出防火、防爆措施,为溶解乙炔站的选址及设计提供技术支持.     

地铁自动检票闸机对人员疏散的影响分析

本文采用计算机仿真技术,建立了地铁车站的疏散模型,获得了每个时刘的人员分布状态,找到了不利于人员疏散的”瓶颈”位置。同时指出了现有地铁站台疏散时间的计算方法的不足之处。通过模拟详细分析了地铁自动检票闸机对人员疏散的影响,模拟结果显示,地铁自动检票闸机的存在,降低了人员疏散的效率,在研制疏散预案以及现场指挥时需要审慎地考虑闸机的影响。文末就此提出了一些合理建议。     

MODIS林火识别算法的验证分析

利用中国境内9起森林火灾事件对MODIS火点识别的理论算法进行验证分析．结果表明：MODIS火点识别的理论算法在中国境内是基本通用的．但受地域和季节变化的影响．应用时可能会遗漏个别低温闷烧的热点;利用火点亮温偏离统计均值标准差的关系来确定阁值．可以避免火点的遗漏;林火点在CH21和CH22上的值比较接近。一般有CH21-CH22〈20K。而噪声点在两个波段上的亮温差异比较大。根据以上知识．提出了改进MODIS林火热点识别算法的建议。     

Removal of heavy metals from a contaminated soil using tartaric acid

This study reports the feasibility of remediation of a heavy metal （HM） contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinetics of riM dissolution/desorption and to predict equilibrium concentrations of HMs in soil leachate. The changes of HMs in different fractions before and after tartaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartaric acid was effective for removal of riMs from the contaminated soil, attaining 50%-60% of Cd, 40%-50% of Pb, 40%-50% of Cu and 20%-30% of Zn in the pH range of 3.5-4.0 within 24 h. Mass transfer coefficients for cadmium （Cd） and lead （Pb） were much higher than those for copper （Cu） and zinc （Zn）. Sequential fractionations of treated and untreated soil samples showed that tartaric acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fraciton were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is needed before the method can be practically used for in situ remediation of contaminated sites.     

Ecological effects of crude oil residues on the functional diversity of soil microorganisms in three weed rhizospheres

Ecological effects of crude oil residues on weed rhizospheres are still vague. The quantitative and diversity changes and metabolic responses of soil-bacterial communities in common dandelion （Taraxacum officinale）, jerusalem artichoke （Silphiurn perfoliatum L.） and evening primrose （A colypha australis L.） rhizospheric soils were thus examined using the method of carbon source utilization. The results indicated that there were various toxic effects of crude oil residues on the growth and reproduction of soil bacteria, but the weed rhizospheres could mitigate the toxic effects. Total heterotrophic counting colony-forming units （CFUs） in the rhizospheric soils were significantly higher than those in the non-rhizospheric soils. The culturable soil-bacterial CFUs in the jerusalem artichoke （S. perfoliatum） rhizosphere polluted with 0.50 kg/pot of crude oil residues were almost twice as much as those with 0.25 kg/pot and without the addition of crude oil residues. The addition of crude oil residues increased the difference in substrate evenness, substrate richness, and substrate diversity between non-rhizospheric and rhizospheric soils of T. officinale and A. australis, but there was no significant （p〉0.05） difference in the Shannon＇s diversity index between non-rhizospheric and rhizospheric soils of S. perfoliatum. The rhizospheric response of weed species to crude oil residues suggested that S. perfoliatum may be a potential weed species for the effective plant-microorganism bioremediation of contaminated soils by crude oil residues.     

Effects of cerium on growth and physiological mechanism in plants under enhanced ultraviolet-B radiation

Effect of cerium （Ce^3＋） on the growth, photosynthesis and antioxidant enzyme system in rape seedlings （Brassica juncea L.） exposed to two levels of UV-B radiation （T1： 0.15 W/m^2 and T2：0.35 W/m^2） was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44. 1%（T1） and 21.4%-49.3% （T2）, compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6%（T1） and 20.3%-42.6% （T2）. For Ce＋UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3%（Ce＋T1） and 10.8%-28.4%, 7.0%-27.8%（Ce＋T2）, lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9%（T1） and 20.9%- 56.9%（T2）, whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase（SOD）, catalase （CAT） and peroxidase （POD） by 6.9%, 22.8%, 21.5%, 9.5%（T1） and 36.6%, 122.3%, 103.5%, 208.9%（T2）, respectively. The reduction of the photosynthetic parameters in Ce＋UV-B treatments was lessened to 3.2%-13.8%（Ce＋T1） and 4.9%-27.6%（Ce＋T2）, and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6%（Ce＋T1） and 30.1%, 116.7%, 75.4%（Ce＋T2）. These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to TI level of UV-B radiation is superior to T2 level.     

新媒体对旅游地生命周期的非线性影响——基于SEIR信息传播模型

旅游地生命周期理论是旅游地理学的经典理论.它可以较好地判断旅游地的发展阶段,并在一定程度上预测其发展趋势,为制定针对性的发展战略提供理论依据.但在新媒体的影响下,出现许多"网红"旅游地,其发展变化趋势与传统旅游地生命周期具有许多不同.综合运用SEIR模型和广告预算模型,通过模拟游客量,描述了新媒体对旅游地生命周期的非线性影响,并选择青海茶卡盐湖、重庆洪崖洞、西安永兴坊为例验证模型的有效性.综合所有模拟结果,得出以下结论:旅游地生命周期在新媒体影响下可能演变为"二次增长型"、"传统S型"、"先增后降型"、"短期波动型"4种形态,其具体形态变化取决于游客的信息传播意愿和旅游意愿以及旅游地发展阶段.研究结果对旅游地生命周期理论进行了有效的补充,同时可以为信息时代旅游景区的发展提供实践指导.     

“T”型地铁换乘站多点火灾工况下综合火灾危险性研究

为探究大型地铁站多线路火灾场景中的综合危险性,采用火灾动力学软件FDS构建“T”型换乘站全尺寸模型,对不同火源位置、不同火源功率以及是否开启地铁排烟风机等12组工况进行数值模拟;采用性能化方法确定可用疏散时间,并通过综合火灾风险评估方法计算各工况总安全指数。结果表明:1号线站厅层和2号线站台层双点火灾为最不利火灾场景;1号线站台层和2号线站厅层双点火灾为相对安全火灾场景;火源功率的增大会增加地铁火灾危险性,但不同火源位置工况中的安全指数变化趋势相似;排烟模式开启前,1号线站厅层火灾会导致较大的火灾危险性;排烟模式开启后,地铁总安全指数显著上升且安全指数变化趋势改变,此时2号线站台层火灾会导致较大的火灾危险性。