外墙保温材料在火灾中的燃烧现象小尺寸实验研究

利用外墙保温材料的小尺寸燃烧实验来研究外墙保温材料在火灾过程中的燃烧特性,分析总结外墙保温材料在火灾过程中的燃烧现象.建立外墙保温材料火灾实验模型,对外墙保温材料火灾实验的实验方法以及数据测定方式进行了介绍.采用不同阻燃性质的保温材料,研究阻燃成分阻止竖向燃烧的效果.观察不同的保温材料在燃烧过程中的点燃性能.根据材料的阻燃性能、点火位置、固定方式的不同,总结燃烧痕迹的变化规律.分析非阻燃材料在燃烧的过程中的熔滴生成,发现产生的熔滴对未燃保温材料的点燃现象.观察不同的保温材料在燃烧过程中的烟气生成及烟气层的形成.通过小尺寸火灾试验的方法来研究建筑外墙保温材料火灾的特性,提出使用阻燃型外墙保温材料的必要性.     

城市管道天然气在土壤中泄漏扩散实验研究

天然气在土壤中扩散行为的实验研究对埋地管道泄漏点的科学定位及泄漏事故的预防具有重要意义.采用全尺度气体泄漏实验系统,模拟真实埋地管道泄漏场景,对泄漏后的天然气在土壤中的扩散对流过程进行实验研究.基于自行研制的气体检测与数据采集系统和GasClam地下气体在线监测仪,分析天然气在土壤中的对流扩散规律.结果表明:埋地管道泄漏后天然气在土壤中的对流扩散过程可以分为4个阶段:孕育阶段、陡然增长阶段、缓慢增长阶段和稳定阶段,其浓度随泄漏时间的变化过程符合S型曲线特征.天然气扩散至检测点所需时间与距泄漏口距离呈现近似的幂指数关系.当检测点位于泄漏口附近区域时,泄漏压力起主导作用.当检测点位于远离泄漏口区域时,泄漏量起主导作用.     

埋地石油管道交流腐蚀风险等级评估

随着我国现代化进程的加快,管道建设与电力设施的建设呈现出高速发展的局面.然而,高压交流、直流电力设施对埋地管道存在着严重的干扰腐蚀情况.采用正交实验的方法,重点关注交流腐蚀对埋地管道的影响因素,并得出其相互间的数学关系,然后综合腐蚀机理以及正交实验结果,通过正交实验的筛选过程确定主要因素、次要因素以及影响较小的因素,选择合理的指标,运用故障树分析、专家咨询以及二手资料的分析法,并参考国内外的研究现状,全面吸收、归纳、重组、增删现有的评价指标,建立埋地管道交流腐蚀风险等级评估指标体系,运用模糊数学综合评价的方法全面系统的评估交流腐蚀风险等级,从而为埋地管道的安全管理提供可靠的数据.     

超细冷气溶胶抑制油气预混爆炸实验研究

大型油罐区火灾事故往往伴随着油气爆炸,对应急救援消防官兵生命安全带来威胁.具有可压缩性、流动性和弥散性特征的超细干粉冷气溶胶对泄漏可燃油气爆燃爆轰有抑制作用.采用三路进气20L球试验装置模拟油气-空气与超细干粉冷气溶胶预混点火燃爆过程,实验结果表明:超细干粉冷气溶胶具有物理和化学双重抑爆作用,随着抑爆剂用量的增大其最大爆炸压力和最大爆炸压力上升速率呈下降趋势,且爆炸感应期明显被滞后;抑爆过程油气爆炸指数快速下降后趋于稳定,抑爆效果与超细粉体本身特性、抑爆剂用量及油气点火时刻有关.该研究有助于优化油气环境的最佳抑爆条件,对大型储油罐区油气防火防爆防护和抑爆技术的应用具有积极意义.     

Relationship between near-surface morphological traits of familiar plants and their ability for sediment retention in a dry-hot valley北大核心CSCD

To explore the sediment interception capacity of plants and its relationship with the surface morphological traits of plants, we used laboratory simulations and off-site flume experiments to study the ability for sediment retention of six familiar species: Leucaena leucocephala (LL), Melia azedarach (MA), Dodonaea viscosa (DV), Coriaria sinica (CS), Heteropogon contortus (HC), and Eulaliopsis binata (EB) aver two growth periods in the dry-hot river valley of the Jinsha River. We analyzed the relationship between near-surface morphological traits of individuals of six species and their ability for sediment retention. Our study resulted in three main observations. (1) In the flume experiment, three-month seedlings and one-year old seedlings of the six species showed different abilities for sediment retention. In the three-month seedlings, the ability for sediment retention of CS was the highest, followed by MA and LL, whereas it was the lowest in HC and EB. However, in one-year old seedlings, the ability for sediment retention of CS was the highest, but the ability for sediment retention of HC and EB was better than those of MA and LL. Hence, the ability for sediment retention of the six species fluctuated between different growth periods. (2) The three-month old and one-year old seedlings of all six species showed different near-surface morphological traits. (3) The sediment mass was significantly and positively correlated with near-surface leaf areas, crown lengths, crown widths, stem dry matter densities at the intersection volume, and above-ground biomass, but significantly and negatively correlated with the angle between stem and ground, indicating that these latter are the main near-surface morphological traits able to affect sediment retention. In addition, the sediment mass was also correlated (positively and negatively) with the stem epidermal crack number, stem dry matter content, leaf dry matter content at the intersection volume, and dry mass per unit volume of the intersection volume, which could also reflect the ability of sediment retention. We conclude that in the areas where plant measures are used to control soil erosion and intercept sediment, the key, above-mentioned plant morphological factors should be taken into account in order to select the optimal plant species. © 2018 Science Press. All rights reserved.     

草甘膦对雄性大鼠睾酮合成的影响

探讨草甘膦亚慢性染毒对雄性大鼠睾酮合成的影响。雄性SD大鼠按体重随机分为对照组(0 mg·kg~(-1))、低剂量组(50 mg·kg~(-1))、中剂量组(200 mg·kg~(-1))和高剂量组(800 mg·kg~(-1)),连续灌胃染毒,第4、8和12周时分别处死一批动物,采集血液和脏器。放射免疫分析法检测大鼠血清中卵泡刺激素(follicle stimulating hormone,FSH)、黄体生成素(luteinizing hormone,LH)、睾酮(testosterone,T)、雌二醇(estradiol,E2)水平; HE染色法(苏木精-伊红染色法)观察睾丸病理学变化;免疫组化法检测3β-羟基类固醇脱氢酶(3beta-hydroxysteroid dehydrogenase,3β-HSD)、类固醇激素合成急性调节蛋白(steroid synthesis of acute regulatory protein,St AR)、细胞色素P450胆固醇侧链裂解酶(cytochrome P450 cholesterol side chain lyase,P450scc)和17β-羟基类固醇脱氢酶(17beta-hydroxysteroid dehydrogenase,17β-HSD)蛋白表达水平。随染毒剂量和时间的增加,大鼠血清FSH和T水平呈下降趋势,第12周高剂量组FSH水平明显低于对照组(P0.05),第8周和第12周高剂量组T水平明显低于对照组(P0.05),LH和E2水平各组间无统计学差异(P0.05)。组织病理学可见中、高剂量组睾丸生精小管、生精细胞、间质区结构被破坏。随草甘膦染毒剂量的增加,St AR和P450scc蛋白表达水平与对照组相比显著下降(P0.05),3β-HSD和17β-HSD蛋白表达水平在各组间无差异(P0.05)。草甘膦能降低血清T水平,抑制T合成相关蛋白St AR和P450scc的表达,干扰T的合成过程,具有雄性生殖毒性作用。     

内蒙古典型草原土壤及其水文过程对灌丛化的响应

基于野外观测和室内试验相结合的方法,研究了内蒙古典型草原小叶锦鸡儿灌丛化过程对土壤和土壤水文过程的影响,旨在为干旱半干旱区环境保护和恢复提供理论基础。结果表明,斑块尺度上,灌丛斑块土壤有机质和全氮含量分别是草地斑块的1.54倍和1.16倍;灌丛斑块平均沙粒、粉粒和粘粒含量是草地斑块的0.87倍、1.34倍和1.35倍;灌丛斑块土壤容重是草地斑块的0.97倍;灌丛斑块钙积层上表面出现深度是草地斑块的1.27倍。地形等自然条件也是形成土壤异质性的重要因子,坡面尺度上,灌丛和草地斑块土壤有机质、全氮、土壤容重、土壤钙积层上表面出现深度呈自坡顶向坡下方向增加的趋势。染色示踪实验表明,灌丛斑块土壤剖面湿润锋和土壤水分入渗速率分别是草地斑块的1.36倍和5.16倍,草地斑块0~10cm土层对水分的响应较敏感,而灌丛斑块25 cm以下土层对水分的响应较敏感。研究认为,灌丛化过程增强了土壤空间异质性,灌丛斑块能将土壤水分快速输送并存储于深层土壤中,灌丛斑块是土壤养分和水分富集区,灌木植物的定居和发展过程与土壤形态之间形成了正反馈。     

开展安全质量标准化提升企业安全管理水平

介绍了公司安全质量标准化试点工作的开展情况,总结了试点工作收到的效果,并对下一步如何更深入地开展安全质量标准化,提升企业安全管理水平进行了阐述.     

典型草原抗风蚀能力的实验研究

为了了解人为干扰对典型草原抗风蚀能力的影响,采用风洞实验的方法对不同干扰条件下典型草原原状土的抗风蚀能力进行了研究.不同时间禁牧草原的风洞实验结果表明,禁牧典型草原的风蚀量和风蚀率都明显低于自由放牧草原,而且,在相同风速下,禁牧时间越长,侵蚀率及侵蚀量越小;草原开垦后,土壤的侵蚀率和侵蚀量远远高于典型草原,而且风速越大,相差越大;草原土壤侵蚀率随风速的增加而增加,但受草原土壤可侵蚀量的限制.另外,人工模拟干扰实验表明,典型草原土壤的侵蚀率与干扰程度呈直线相关关系.结果说明:放牧及耕作会使典型草原的抗风蚀能力明显降低,而禁牧可以有效提高其抗风蚀能力.在典型草原区,实行禁牧是遏制草原退化的有效措施.     

Simulated Limnological Effects of the Shasta Lake Temperature Control Device

We estimated the effects of a temperature control device (TCD) on a suite of thermodynamic and limnological attributes for a large storage reservoir, Shasta Lake, in northern California. Shasta Dam was constructed in 1945 with a fixed-elevation penstock. The TCD was installed in 1997 to improve downstream temperatures for endangered salmonids by releasing epilimnetic waters in the winter/spring and hypolimnetic waters in the summer/fall. We calibrated a two-dimensional hydrodynamic reservoir water quality model, CE-QUAL-W2, and applied a structured design-of-experiment simulation procedure to predict the principal limnological effects of the TCD under a variety of environmental scenarios. Calibration goodness-of-fit ranged from good to poor depending on the constituent simulated, with an R ² of 0.9 for water temperature but 0.3 for phytoplankton. Although the chemical and thermal characteristics of the discharge changed markedly, the reservoir's characteristics remained relatively unchanged. Simulations showed the TCD causing an earlier onset and shorter duration of summer stratification, but no dramatic affect on Shasta's nutrient composition. Peak in-reservoir phytoplankton production may begin earlier and be stronger in the fall with the TCD, while outfall phytoplankton concentrations may be much greater in the spring. Many model predictions differed from our a priori expectations that had been shaped by an intensive, but limited-duration, data collection effort. Hydrologic and meteorological variables, most notably reservoir carryover storage at the beginning of the calendar year, influenced model predictions much more strongly than the TCD. Model results indicate that greater control over reservoir limnology and release quality may be gained by carefully managing reservoir volume through the year than with the TCD alone. RID=" ID=" Author to whom correspondence should be addressed. e-mail: John_Bartholow@USGS.gov