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521.
本文探讨了森林生态系统中植物--土壤--大气CO2气体交换测定装置。本装置在草原生态系统植物群落光合作用测定装置基础上改进而来,适用于森林地带无交流电源,效能运输不便的地区,利用便携式CO2红外线分析仪和粉尘采样器替代气泵,具有经济,轻便,实用等特点。 相似文献
522.
陈子明 《城市环境与城市生态》1997,(2)
在工业企业噪声环境影响评价中,由于测点与测量时段选择的不妥,导致测量及预测值“以偏代全”的结果;本文提出了测点合理布设与测量,预测时段科学选择的原则,以使测量与预测结果能较好地符合项目建成前、后噪声环境实际状况。 相似文献
523.
影响高锰酸盐指数测定准确性的主要因素有样品酸度、蒸馏水水质、高锰酸钾溶液浓度、水浴加热温度和滴定时间。通过环境标准样品的分析试验,考察这5个因素对高锰酸盐指数的影响程度; 相似文献
524.
空气微生物研究方法进展与展望 总被引:8,自引:0,他引:8
着重论述了空气微生物气溶胶的研究方法,主要有培养基法和非培养基法。培养基法是传统的微生物研究方法,需要花费大量的时间和劳动力,只能够检测活的能够在培养基上生长的微生物,可以大致反映空气中的微生物气溶胶。非培养基法,主要是PCR法,具有敏感性高、快速、特异性强等特点,能够检测出环境样品中绝大多数的微生物,是一种微生物气溶胶检测的有效途径。最后指出实时持续的监测是将来空气微生物研究的努力方向和发展趋势。 相似文献
525.
二次风口的合理布设是实现炉膛内气体混合均匀、反应完全的有效措施之一,运用CFD技术进行二段往复炉排焚烧炉二次风口的辅助设计,借助PHOENICS软件模拟二次风口对炉内流场的影响。通过模拟发现,二次风口的布设可明显提高烟气的湍流程度.前后墙各设一排直径为0.04m的二次风口可以实现最佳的炉膛流场工况。 相似文献
526.
Hubert?ChansonEmail author Richard?Brown John?Ferris Ian?Ramsay Kevin?Warburton 《Environmental Fluid Mechanics》2005,5(6):553-575
In natural systems, mixing is driven by turbulence, but current knowledge is limited in estuarine zones where predictions
of contaminant dispersion are often inaccurate. A series of detailed field studies was conducted in a small sub-tropical creek
in eastern Australia. Hydrodynamic, physio-chemical and ecological measurements were conducted simultaneously to assess the
complexity of the estuarine zone, notably the interactions between turbulence and environment. The measurements were typically
performed at high frequency over a tidal cycle. The results provide an original data set to complement long-term monitoring
and a basis for a more detailed study of mixing in sub-tropical systems. Unlike many long-term observations, velocity and
water quality scalars were measured herein with sufficient spatial and temporal resolutions to determine quantities of interest
in the study of turbulence, while ecological indicators were sampled systematically and simultaneously. In particular the
results yielded contrasted outcomes, and the finding impacts on the selection process for key water quality indicators. 相似文献
527.
Yorianta?Sasaerila Regine?Gries Gerhard?Gries Grigori?Khaskin Skip?King Stephen?Takács Hardi?) 《Chemoecology》2003,13(2):89-93
Summary. During peak calling activity by male oil palm bunch
moths, Tirathaba mundella Walker (Lepidoptera: Pyralidae), their
hairpencils, wings or entire body were extracted in hexane. Gas
chromatographic-electroantennographic detection (GC-EAD) analyses of
hair pencil extracts revealed four compounds that consistently elicited
responses from female antennae. The NMR spectrum of isolated compound 1,
and mass spectra and retention indices of compounds 1–4 suggested that
they were (3S,6S)-2,2,6-trimethyl-6-vinyl-tetrahydro-pyran-3-ol (1),
4-hydroxy-3-methoxy-benzaldehyde (2, vanillin),
6,10,14-trimethyl-2-pentadecanone (3), and
6,10,14-trimethyl-2-pentadecanol (4). Comparative GC and GC-MS analyses
of hair pencils extract and synthetic standards confirmed these
structural assignments. Moreover, comparative chromatography of
synthetic and hairpencil-isolated 1 on a Cyclodex-B column (which
separated the four stereoisomers with baseline resolution) revealed that
male T. mundella produce the SS-stereoisomer (SS-1). In field cage
bioassay experiments in Palembang, Indonesia, synthetic SS-1 and
vanillin in combination, but not singly, attracted female T. mundella.
SS-1 plus vanillin were as effective as male T. mundella in attracting
females. Compounds 3 and 4 did not enhance the blend's attractiveness.
Received October 11 2002; accepted March 14, 2003.
R1D="
Correspondence to: Gerhard Gries, email: gries@sfu.ca 相似文献
528.
二硫代氨基甲酸盐型除油剂的性能研究 总被引:3,自引:0,他引:3
分别用二乙胺、乙二胺、三乙烯四胺与CS2 反应 ,合成了三种二硫代氨基甲酸盐 ,试验了其除油性能 .结果表明 ,三 ( 1 ,2 亚乙基 )四氨基四 (二硫代甲酸钠 )对含有一定量Fe2 + 的油田污水有较好的除油效果 .每升污水中加入 1 0mg除油剂 ,就能在1 5min内将污水中的油含量降至 1 0mg·l- 1.通过改变二硫代氨基甲酸盐的浓度、污水中Fe2 + 的浓度、搅拌速度、氨基的结构 ,发现多官能团的二硫代氨基甲酸盐 ,在较低的搅拌速度下 ,除油效果较好 . 相似文献
529.
Laboratory experiments have been carried out to investigate the effects of a sloping wall headland on the flow characteristics and the associated concentration distributions from a point source around the headland. A semi-conical headland with a slope of 1:2 was set up in a flow basin, 4.8 m long and 3.8 m wide. In this paper, the experimental results of a steady shallow-water current are reported. Three dimensional flow velocities in the basin were measured using Sontek-ADV instrument. The dye concentration levels in the basin were measured by two fluorometers. The experimental results showed a large-scale re-circulation region behind the semi-conical headland. The peak turbulence energy, at about 53% of the local kinetic flow energy, coincides with the region of high velocity gradient. Significant vertical flows were observed around the area near the downhill slope of the headland, with a maximum ratio of vertical to horizontal velocities being about 22%. Such relatively significant vertical scouring velocities, coupled with strong turbulence energy and high horizontal velocity gradients in the same region, could cause severe bed erosion. The experimental results have also been compared with the predicted results of a depth-averaged numerical model. The predicted eddy structure and the concentration distribution in the re-circulation area were found to compare favourably with the experimental results. However, the discrepancies in the flow velocities and the concentration levels near the headland were apparent. It was observed that the dye concentration continued to spread in the cross-stream direction after passing the headland, whereas only a limited extent of the lateral spreading was predicted by the numerical model further downstream of the headland. 相似文献
530.
对转入除草剂抗性基因bar及来自病毒TuMV的/VIa基因的不结球白菜纯合株系二代进行了田问生物学性状调查,结果表明,转基因白菜的植物学性状与其未转基因对照材料相比,无明显差别;但在涉及其生存竞争力的一些生物学性状,如发芽势、花粉活力、种子库存力等方面,比对照材料弱,其经济性状也比对照稍差.获得的转基因性状——除草剂抗性,能稳定遗传,并在田间很好表达;NIa基因介导的TuMV抗性在露地开放栽培条件下,不能很好表达,转基因株染病较重.对产生以上现象的原因进行了分析讨论.图3表5参16 相似文献