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211.
CASS处理技术的原理和应用 总被引:1,自引:0,他引:1
介绍了CASS工艺的原理、特点、核心构筑物和设计、运行中应注意的主要问题以及常见故障的排除方法。 相似文献
212.
213.
Lance H. Gunderson 《Journal of the American Water Resources Association》1989,25(3):573-579
ABSTRACT: Four experiments were made to document and account for differences in evaporation data that were calculated using pans equipped with float-activated recorders and pans with hook gauge/rain gauge instrumentation. Paired in-pan comparisons indicated that evaporation differences were not due to the technique of measuring water level within the pan. Also, the recorder float-lag did not account for the differences. By sampling rainfall events, it was found that evaporation pans and standard (8 in. orifice) rain gauges record significantly different amounts of rain, which results in differences in calculated evaporation on rainy days. Monitoring networks with evaporation pans should have uniform instrumentation that accurately records rainfall into the pans for consistent results. 相似文献
214.
污水回用处理技术现状分析 总被引:22,自引:1,他引:22
概括地介绍了污水回用的国内外发展现状,水质标准以及处理技术,并对其效益作了简要分析。 相似文献
215.
Prenatal screening was carried out in Havana City, Cuba, as part of a National Medical Genetics Programme, in order to detect elevated alpha-fetoprotein concentration in maternal serum (MS-AFP). A total of 97 900 pregnant women between 15 and 19 weeks of pregnancy were tested from 1982 to 1985. A double-antibody-sandwich technique was used. 173 malformed fetuses were detected. Confirmation was by ultrasonography, elevated AFP values in a second serum sample and in amniotic fluid and acetylcholinesterase. No termination of a normal pregnancy occurred. The screening of all pregnancies is easy, economical and useful for detecting not only fetuses suffering from open Neural Tube Defects (NTDs) and other severe disorders but also pregnancies at risk of further complications. 相似文献
216.
DDT污染土壤的植物修复技术 总被引:2,自引:0,他引:2
本文报道用植草方法研究为DDT及其主要降解产物污染土壤的植物修复技术。在污染物的浓度为 0 .2 15mg/kg的土壤中 ,种植 10种草 3个月后DDT及其主要降解产物的总含量分别降低 19.6 %— 73.0 %。种植不同品种的草对土壤中污染物有不同的去除能力 ,其中以种植丹麦产的Taya草 (Per .ryegrass)与美国产的Titan草 (Tallfescue)为最强。用种植草的方法修复受DDT及其主要降解产物污染的土壤是一项可行的技术。在去除土壤中DDT的作用上 ,草的吸收是轻微的 ,只占原施药量的 0 .13%— 1.0 8% ,土壤中污染物消失的主要因素是土壤中生物降解作用的结果。 相似文献
217.
Trace metal levels in freshwater fish, sediment and water 总被引:1,自引:1,他引:1
Sandor Z Csengeri I Oncsik MB Alexis MN Zubcova E 《Environmental science and pollution research international》2001,8(4):265-268
The trace metal concentrations in water, sediment and aquatic organisms, such as fish, could indicate the level and tendency of the pollution. This is important not only for the protection of the environment, but for evaluation of the quality of fish meat either captured from natural waters or cultured in fishponds. The total trace metal concentrations in samples of fish from different regions of Hungary and from different species have been determined by using an X-ray fluorescence technique (EDXRF). Water, sediment and fish samples from fishpond systems with different feeding and stocking has also been analyzed. In the case of zinc contents, differences have been traced between the cultured and wild common carp. In the case of common carp reared under different feeding conditions, differences were also observed in the zinc concentration. The retention of the trace metals in the fish has been studied by measuring the levels in sediment, water and feed. The different retention can be explained by the different availability of zinc in the applied feeds, which can be related to the presence of different metal species in the feeds. 相似文献
218.
低温等离子体技术改善生物膜反应器载体表面性能的研究 总被引:4,自引:0,他引:4
通常,微生物及广为应用的多聚体型生物载体表面均带有有负电荷。两者间产生的静电斥力严重阻碍了载体表面生物膜的形成。为强化微生物的载体上附着,提出了载体表面电荷改性新技术;低温等离子体氧化-Fe离子沉积技术。研究了4种等离子体对4种聚合载体(PE、PP、PS和PVC)的氧化强度及Fe^3+在处理后载体上的沉积。实验表明,处理后的载体表面生物膜形成速度加快,生物量显著增加,这项新技术为开发生物膜反应器新 相似文献
219.
The timing of chemical signaling with urine in dominance fights of male lobsters (Homarus americanus) 总被引:2,自引:0,他引:2
Chemicals carried in the urine are a rich source of information about the identity, sex, aggressive motivation, and other
attributes of an animal. In agonistic interactions, animals should be careful about disclosing such information, since it
can be used by receivers to the disadvantage of the sender. By adjusting the timing of urine release, the signaler may still
influence the behavior of the receiver to its own benefit. Here we investigate the urine signaling of American lobsters (Homarus americanus), necessary for the maintenance of dominance, using a catheter technique with high temporal resolution. We hypothesize that
urine release in lobster fights is not continuous but restricted to moments that may elicit a reaction in the receiver beneficial
to the sender. We found that eventual winners signaled more readily in the initial phase of the fight. Eventual losers did
not show such initial urination. This suggests that a confident lobster may use urine signals to influence the behavior of
its opponent into giving up the fight at an early stage. For both winners and losers, urine release is linked to offensive
behavior and increases as the intensity of agonistic behavior increases. The coupling of urine release to offensive behaviors
appears to improve both the reliability and efficacy of the chemical signal. Releasing urine under the increasing risk of
inflicting injury during the fight provides a handicap that may ensure reliability of the threat signal. Furthermore, the
immediate coupling of urine components to offensive behavior may help to consolidate the receiver"s memory of the signaler"s
individual scent and thus facilitate future recognition of the dominant animal.
Received: 6 October 1999 / Accepted 28 August 2000 相似文献
220.