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911.
混凝土结构火灾损伤检测技术研究 总被引:3,自引:0,他引:3
对混凝土在火灾条件下的热像平均温升、抗压强度、超声波速和损伤深度进行了检测,获得了混凝土热像平均温升、抗压强度、超声波速和损伤深度随着温度变化的规律,并对影响混凝土热像平均温升和超声波速的因素进行了分析,为混凝土结构火灾损伤程度的现场检测提供了一种科学的技术方法。 相似文献
912.
913.
考察了Cu2+、Cd2+、Ni2+、Fe2+4种重金属离子对2-氯酚(2-CP)厌氧降解速率的影响,并通过描述金属离子抑制作用的修正方程对实验进行拟合,研究了其动力学特征.结果表明,在0~500mg/L投加浓度范围内,Fe2+对2-CP的厌氧降解过程基本不抑制,Ni2+、Cu2+、Cd2+则存在明显抑制,抑制程度Cu2+﹥Ni2+﹥Cd2+.相同的抑制强度下,抑制浓度CIP-Cu﹤CIP-Ni﹤CIP-Cd.修正方程能较好地表征金属离子的抑制作用与该离子对降解速率的最大抑制浓度(I*)以及投加浓度之间的定量关系.由该方程拟合结果可得到Cu2+、Cd2+、Ni2+对25mg/L 2-CP降解的I*值分别为458.7,1693.5,1528.5mg/L,I*及指数m值的大小表明金属离子对2-CP厌氧降解的抑制Cu2+﹥Ni2+﹥Cd2+. 相似文献
914.
915.
Qingyun CHANG Jingwen ZHANG Xin DU Jingjun MA Jingci LI 《Frontiers of Environmental Science & Engineering》2010,4(2):187-195
A simple and efficient liquid-phase microextraction (LPME) technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction (USAE-SFODME) combined with flame atomic absorption spectrometry, for the extraction and determination of trace copper in water samples. 1-(2-Pyridylazo)-2-naphthol (PAN) was used as chelating agent. Microextraction efficiency factors (including extraction solvent type, extraction volume, time, temperature, and pH), the amount of the chelating agent, and salt effect were investigated and optimized. Under the optimum extraction conditions, figures of merit of the proposed method were evaluated. The calibration graph was linear in the range of 20–600 mg·L−1 with a detection limit of 0.76 mg·L−1. The relative standard deviation (R.S.D) for ten replicate measurements of 20 and 400 mg·L−1 of copper was 3.83% and 2.65%, respectively. Finally, the proposed method was applied to tap water, river water, and sea water, and accuracy was assessed through the analysis of certified reference water or recovery experiments. 相似文献
916.
Ståle Liljedal Geir Rudolfsen Ivar Folstad 《Behavioral ecology and sociobiology》2008,62(11):1805-1811
In postcopulatory sexual selection both sperm competition and cryptic female choice are considered to be important selective
agents, but their relative importance for male fertilization success has received little attention. We tested whether sperm
quality, male spawning coloration, male heterozygosity, and genetic overlap with the female explained a male’s fertilization
success in controlled in vitro fertilization competition trials between equal numbers of sperm from pairs of male Arctic charr
(Salvelinus alpinus), an external fertilizer. Offspring were genotyped to determine each males’ share of paternity. The velocity of a male’s
sperm relative to the velocity of the competing male’s sperm was the best predictor of male fertilization success. Yet, sperm
velocity was not related to spawning coloration or male heterozygosity. In fact, the most brightly colored male in a pair
had the lowest fertilization probability. This could result from cryptic female choice for pale males, but might rather be
a result of paler males producing more competitive sperm than more colored males. Furthermore, the more microsatellite alleles
a male shared with the female relative to the competing male, the higher fertilization success he had. We argue that this
latter may be an effect of assortative cryptic female choice, which might prevent hybridization with sympatric Arctic charr
morphs or one form of kin selection. 相似文献
917.
流速对河道系统截留氮、磷的影响 总被引:3,自引:1,他引:2
为有效阻控太湖湖西地区小流域河流中的氮、磷进入太湖,对比了不同流速下河道对河流上覆水和间隙水中NH4+-N,NO3--N,NO2--N和可溶磷的截留情况,同时通过实验室模拟河道探讨了不同流速下氮、磷截留的机理. 结果表明,河道系统本身不太稳定,在有外界条件(如其他河流的汇入)作用下可以引起一系列的变化. 流速对河道中NH4+-N,NO3--N,NO2--N和可溶磷的截留有较大影响,在保证初始条件和外部条件相同的前提下,快速流(流速为1.00 cm/min)对氮、磷的截留量最小,中速流(流速为0.35 cm/min)次之,慢速流(流速为0.17 cm/min)对氮、磷的截留量最大. 在整个过程中流速对氮的截留基本上是先增加再略有下降,而对磷的截留是先增加再逐渐趋于平稳. 相似文献
918.
地壳垂直形变场与强震关系研究 总被引:2,自引:0,他引:2
根据不同时期的地壳垂直形变速度,研究了中国大陆地壳的垂直演变特征,结合1965~2005年中国大陆地区M≥7级的大震,研究了垂直形变演变与强震活跃时间段和相对平静时段的关系。并且依据1951~1990年中国大陆垂直形变速率图计算分析了垂直形变速率梯度,研究了高梯度带与大震的分布关系。中国大陆垂直形变速度的演变表明,在中国大陆出现NWW向的上升带和下降带相间分布,而且以上升为主,西部呈现“南升北降”等形变特点时,中国大陆的大震活动也相对活跃,当大面积下降变化为主,尤其是青藏高原表现为下降时,大震相对平静。M≥7级的地震绝大多数发生在水准网控制的高梯度带上,发生在不同高梯度带的交汇部位,转折部位、或者局部变化较突出的附近地带。 相似文献
919.
Thermo-kinetic modelling of dust explosions 总被引:1,自引:0,他引:1
The guidelines for protection and mitigation against hazard coming from dust explosion require the knowledge and then the evaluation either experimentally or theoretically of the thermo-kinetic parameters (i.e. KSt, Pmax). We developed a numerical tool for the evaluation of the thermo-kinetic parameters of dust explosion. This model is based on the simulations of the combustion reaction by means of a detailed reaction mechanism assuming that the pyrolysis/devolatilization step is very fast and then gas combustion is controlling dust explosion. The model allows then the determination of the most conservative values of KSt, Sl, Pmax. In the present paper we calculated the deflagration index and the laminar burning velocity for dusts utilized in various process industries (i.e. cornstarch, polyethylene, cellulose) as function of dust concentration. The obtained data were successfully compared with the available experimental results. 相似文献
920.
Shin-ichi Sakai Yukio Noma Akiko Kida 《Journal of Material Cycles and Waste Management》2007,9(2):151-158
The Japanese Government introduced the Law on Recycling of End-of-Life Vehicles (ELV Recycling Law) in 2002. This law requires
manufacturers to retrieve chlorofluorocarbons (CFCs), airbags, and automobile shredder residue (ASR) from ELVs and to properly
recycle the remaining materials. This framework is compared with European ELV directives. Pilot-scale incineration plant testing
has revealed a greater formation of by-product persistent organic pollutants (POPs) during the primary combustion of ASR compared
to normal municipal solid waste. This may be attributed to the abundance of chlorine, Cu, and Fe in ASR, as Cu and Fe have
been found to catalyze the formation of POPs under certain conditions. However, most by-product POPs were destroyed by the
secondary combustion, and almost all were removed after flue gas treatment. The direct melting system is a shaft-type gasification
and melting technology that has proved effective in many municipal solid waste applications. This system can be applied to
ASR recycling for effective decomposition of brominated flame retardants and polybrominated dioxins. 相似文献