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321.
本研究将氢化物发生(HG)与流动注射分析(FIA)相结合产生PbH_4,采用火焰原子吸收(FAAS)检测铅,灵敏度比FAAS提高了2.5倍,水样加标回收率为91.7~97.8%,相对标准偏差1.6~2.4%之间,分析速度150样次/小时。 相似文献
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Sexual selection is a process that operates through intrasexual competition and intersexual choice for reproduction in both
sexes. Here, we report our work on a polygamous moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), aiming to infer the form and nature of precopulatory sexual selection in males and females.
We show that, although a number of traits measured in each sex are correlated with mating success, the primary selection trait
in females appears to be abdominal thickness and that in males is aedeagus length. As the female’s abdominal thickness is
a reliable signal about the number and developmental stage of eggs, males who select females with thicker abdomens for mating
will gain reproductive benefit, i.e., fertilizing more mature eggs. For females, earlier maturation of their eggs makes the
females more likely to achieve mating earlier in an uncertain world where there is no guarantee that they will find more males
in the future. Sexual selection appears to be the important force behind the evolution of fast egg maturation in females.
We show that, under a male-biased sex ratio, more than 20% of mating fails within a few minutes after the aedeagus has penetrated
into the female’s genitalia, suggesting that females can assess the features of the male aedeagus before allowing insemination
to occur. Dissection and examination of both sexes suggest that a longer aedeagus enhances mating and fertilization efficiency
in this species, supporting the notion that sexual selection is a primary force in the evolution of genital variance. 相似文献
325.
A laboratory study was performed to assess the biodegradation of lube oil in bio-reactor with 304# stainless steel as a biofilm carrier.Among 164 oil degrading bacterial cultures isolated from oil contaminated soil samples, Commaonas acidovorans Pxl, Bacillus sp.Px2, Pseudomonas sp. Px3 were selected to prepare a mixed consortium for the study based on the efficiency of lube oil utilization.The percentage of oil degraded by the mixed bacterial consortium decreased slightly from 99% to 97.2% as the concentration of lube oil was increased from 2000 to 10,000 mg/L. The degradation of TDOC (total dissolved organic carbon) showed a similar tendency compared with lube oil removal, which indicated that the intermediates in degradation process hardly accumulated. Selected mixed bacterial consortium showed their edge compared to activated sludge. Scanning electron microscopy (SEM) photos showed that biofilms on stainless steel were robust and with a dimensional framework constructed by EPS (extracellular polymeric substances),which could promote the biodegradation of hydrocarbons. The increase of biofilm followed first-order kinetics with rate of 0.216 μg glucose/(cm~2·day) in logarithm phase. With analysis of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) combined with removal of lube oil and TDOC, mixed bacterial consortium could degrade benzene and its derivatives, aromatic ring organic matters with a percentage over 97%. 相似文献
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Haifeng Wang Ran Xu Fengting Li Junlian Qiao Bingru Zhang State Key Laboratory of Pollution Control Resource Reuse College of Environmental Science Engineering Tongji University Shanghai China. 《环境科学学报(英文版)》2010,(3)
A laboratory study was performed to assess the biodegradation of lube oil in bio-reactor with 304# stainless steel as a biofilm carrier. Among 164 oil degrading bacterial cultures isolated from oil contaminated soil samples, Commaonas acidovorans Px1, Bacillus sp. Px2, Pseudomonas sp. Px3 were selected to prepare a mixed consortium for the study based on the efficiency of lube oil utilization. The percentage of oil degraded by the mixed bacterial consortium decreased slightly from 99% to 97.2% as the concentration of lube oil was increased from 2000 to 10,000 mg/L. The degradation of TDOC (total dissolved organic carbon) showed a similar tendency compared with lube oil removal, which indicated that the intermediates in degradation process hardly accumulated. Selected mixed bacterial consortium showed their edge compared to activated sludge. Scanning electron microscopy (SEM) photos showed that biofilms on stainless steel were robust and with a dimensional framework constructed by EPS (extracellular polymeric substances), which could promote the biodegradation of hydrocarbons. The increase of biofilm followed first-order kinetics with rate of 0.216 μg glucose/(cm2·day) in logarithm phase. With analysis of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) combined with removal of lube oil and TDOC, mixed bacterial consortium could degrade benzene and its derivatives, aromatic ring organic matters with a percentage over 97%. 相似文献
329.
威海市土地利用规划对生态环境的影响 总被引:1,自引:0,他引:1
新一轮土地利用总体规划修编(2006年-2020年)要求深入分析资源供给、环境容量等限制因素,研究土地利用方式、空间布局对生态环境的影响,提出环境友好型土地利用模式;研究提出有利于环境保护和生态建设的土地利用调控指标和空间管制措施。本文在分析了威海市土地利用现状特点、生态环境状况的基础上,分析了威海市土地利用环境承载力,探讨土地利用规划对生态环境的影响,对合理调整土地利用结构和布局,科学地安排土地利用规划有着十分重要的意义。 相似文献
330.
太湖地区太阳辐射与水温的变化特征及其对叶绿素a的影响 总被引:8,自引:1,他引:7
基于中国科学院太湖湖泊生态系统研究站1993年以来的常规监测资料,利用比较与数理统计相关分析方法对太湖地区的太阳辐射和水温变化特征及其对水体叶绿索a浓度的影响进行分析.结果显示,太湖地区太阳总辐射、光合有效辐射、光合有效辐射占总辐射的比例及水温总体上都呈上升的趋势.其中,光合有效辐射的增长速率大于总辐射的增长速率,年际水温增长率春季秋季>夏季.太阳辐射及水温的年内变化呈夏季大,春秋季次之,冬季最小的特征.此外,太阳辐射和水温与叶绿素a呈显著正相关关系(P<0.01),太阳辐射特别是光合有效辐射和水温的增加为藻类的大量生长和水华暴发提供了良好的物理条件,太湖蓝藻水华初始暴发时间有逐年前移的趋势且水华持续时间逐年增加. 相似文献