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821.
利用衍生化气相色谱法对黄磷诱发氧化苯酚降解产物进行了研究,在磷酸存在下,以甲醇作酯类衍行生试剂,分别和SE-52和HP-17石英毛细管双柱结合GC-MS进行分离定性定量,黄磷诱发氧化苯酚降解产物以羧酸为主,在反应温度50℃时,表现为一级反应特征,速率常数(K):0.077min^-1,半衰期(t1/2):9.0min。 相似文献
822.
味精废水中重金属及金属污染对处理利用的影响 总被引:1,自引:0,他引:1
本文应用等离子光谱(ICP)测试三个厂家味精生产废水中21种金属元素的水平,其中金属元素的总水平分别达19192mg.l^-1,3190mg.l^-1和3161mg.l^-1,对照国内外有关的四项水质标准,三厂家味精生产废水中存在着Fe,Zn等多种重金属或其他金属元素严重超标现象,味精生产废水对青芋存在急性毒性,24,48,72和96h的半致死味精废水浓度LC50分别为6.9%,3.2%,2.5% 相似文献
823.
Female choice on the basis of male traits has been described in an array of taxa but has rarely been demonstrated in reptiles. In the sand lizard (Lacerta agilis), and possibly in other non-territorial reptiles, a male's contribution to a female's fitness is restricted to his genes. In order to choose males of high genetic quality, females have to trade the fitness gain against the costs of active choice. In a Swedish population of sand lizards, long-lived males sired offspring with higher embryonic survival compared to offspring sired by short-lived males. In spite of this female sand lizards did not mate selectively with older and/or larger males. There appeared to be mo reliable cues to male longevity; age-specific male body size was highly variable. Furthermore, estimates of male nuptial coloration did not covary with ectoparasite load and, hence, females cannot use male coloration as a cue to heritable resistance to pathogenic parasite effects. When cues to male genetic quality are poor, or inaccurate, and males make no parental investment, we predict that female choice will be rare. Sand lizard females mating with many partners lay clutches with higher hatching success. Thus, females may obtain good genes for their young by multiple mating, thereby avoiding costs associated with mate choice. 相似文献
824.
添加不同化合态结合的铜离子对其在黄土中吸持及形态的影响 总被引:4,自引:0,他引:4
分别以CuSO4和Cu(NO3)2为吸持质,研究了添加不同化合态结合的铜离子在黄土中的等温吸持及形态分布规律。结果表明:黄土吸持铜离子以碳酸盐结合态为主。当铜离子初始浓度较低时,添加不同化合态结合的铜离子对其在黄土中的吸持及碳酸盐结合态没有明显影响;当铜离子初始浓度超过一定值时,添加不同化合态结合的铜离子对其在黄土中的吸持及碳酸盐结合态的影响随铜离子初始浓度的增加而明显增大。添加不同化合态结合的铜离子,其持有量和碳酸盐结合态含量均随土壤浓度的增大而减小。当铜离子初始浓度较低时,添加不同化合态结合的铜离子对其在黄土中的吸持量及碳酸盐结合态含量随土壤浓度的变化影响不大;当铜离子初始浓度超过一定值时,相同初始浓度条件下CuSO4较Cu(NO3)2会造成更大幅度的变化。 相似文献
825.
采用钙镁试剂 (CLG) 示波计时电位法 ,分别在中性和碱性条件下直接检测天然水中的无机单核铝 [Ali]和总单核铝 [Ala]浓度 .并用该法测定了酸消化水样中的总铝 [AlT],由 [Ala]-[Ali]间接得到有机单核铝 [Alo],[AlT]-[Ala]得到酸溶态铝 [Alr],从而实现了水中五种Al形态的电化学测定 .实验结果表明 :在pH9 0的 0 5mol·1 - 1KCl+ 0 1mol·1 - 1Na2 B4 O7缓冲溶液中 ,CLG切口为Ep1=-0 75V ,加入铝后出现新切口 ,Ep2 =-0 90V ,检测线性范围为 8× 1 0 - 6— 4× 1 0 - 5mol·1 - 1,检测下限为 6× 1 0 - 7mol·1 - 1,在 3× 1 0 - 5mol·1 - 1Al时 ,相对标准偏差为 4 8% (n =1 0 ) .在中性条件下测定的是无机单核铝 ,而在碱性条件下则是总单核铝 (包括无机单核铝和有机单核铝两部分 ) . 相似文献
826.
活性污泥对重金属离子混合物的生物吸附 总被引:20,自引:3,他引:20
采用城市污水处理厂产生的活性污泥研究了影响污泥吸附Zn^2 ,Cu^2 和Cd^2 三种重金属离子的主要因素,在实验条件下,温度对污泥吸附重金属的影响并不显著,而体系Ph值和吸附时间等的影响较为重要,活性污泥对Cu^2 的吸附符合Langmuir模型,Zn^2 则与Freundlich模型的符合程度优于Langmuir模型,Cu^2 的吸附与两个模型的符合程度一致,另外,活性污泥对Cu^2 离子的吸附性能明显高于其他离子,但在实验中未发现不同金属离子之间存在明显吸附抑制或促进。 相似文献
827.
Summary. Phytotoxic activity of single and combined application of water soluble and volatile compounds of Cistus ladanifer on germination and early root growth of subterranean clover was investigated. Total germination, lag and speed of germination
were both inhibited and stimulated, with the activity of volatiles on total germination depending upon the presence of water
solubles. Antagonism between water solubles and volatiles was always found, resulting in a reduction of inhibition or a shift
from inhibition to stimulation. It is suggested that the simultaneous presence of water solubles and volatiles might result
in changes of the chemical nature of metabolites released by C. ladanifer. Early root growth was always inhibited but only by water solubles, and no interaction was found. The ecological implications
of these results are discussed in terms of the exhaustion of competitors seedbanks by a two-step process in which germination
is less inhibited or even stimulated by water solubles and volatiles, followed by a stronger and volatiles-independent inhibition
of early root growth.
Received 13 June 2001; accepted 13 Dezember 2001. 相似文献
828.
Summary. Analysis of South-East Asian troidine swallowtails revealed high variability in the content of aristolochic acids among individuals.
The presence or absence of these compounds depends on the Aristolochia species available as food plant for the larvae. Only one plant species (Aristolochia philippinensis) contained a high concentration of aristolochic acids, while other species from various localities contained none or only
marginal amounts. Whether aristolochic acids have a distinct function in chemical defense of these swallowtails is still an
open question.
Received 11 December 2000; accepted 4 August 2001. 相似文献
829.
Summary. Colonies of two species of Metapone (M. madagascarica, M. new species.) were collected in Madagascar and established in laboratory nests. It could be demonstrated that both species
are specialist predators of termites (Cryptotermes kirbyi). During hunting the ants sting the termites and thereby paralyze and preserve the prey alive. In this way prey can be stored
in the ant nest for extended periods. During foraging and colony emigrations the ants lay chemical trails with poison gland
secretions. Among the seven compounds identified in the venom only methyl pyrrole-2-carboxylate elicits trail following behavior
in both Metapone species.
Received 11 February 2002, accepted 23 February 2002. 相似文献
830.
Byron K. Williams 《Environmental and Ecological Statistics》2001,8(3):269-288
Wildlife management is limited by uncontrolled and often unrecognized environmental variation, by limited capabilities to observe and control animal populations, and by a lack of understanding about the biological processes driving population dynamics. In this paper I describe a comprehensive framework for management that includes multiple models and likelihood values to account for structural uncertainty, along with stochastic factors to account for environmental variation, random sampling, and partial controllability. Adaptive optimization is developed in terms of the optimal control of incompletely understood populations, with the expected value of perfect information measuring the potential for improving control through learning. The framework for optimal adaptive control is generalized by including partial observability and non-adaptive, sample-based updating of model likelihoods. Passive adaptive management is derived as a special case of constrained adaptive optimization, representing a potentially efficient suboptimal alternative that nonetheless accounts for structural uncertainty. 相似文献