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961.
962.
963.
Hongjie Xie Xiaobing Zhou Jan M.H. Hendrickx Enrique R. Vivoni Huade Guan Yong Q. Tian Eric E. Small 《Journal of the American Water Resources Association》2006,42(1):237-256
This study examines NEXRAD Stage III product (hourly, cell size 4 km by 4 km) for its ability in estimating precipitation in central New Mexico, a semiarid area. A comparison between Stage III and a network of gauge precipitation estimates during 1995 to 2001 indicates that Stage III (1) overestimates the hourly conditional mean (CM) precipitation by 33 percent in the monsoon season and 55 percent in the nonmonsoon season; (2) overestimates the hourly CM precipitation for concurrent radar‐gauge pairs (nonzero value) by 13 percent in the monsoon season and 6 percent in the nonmonsoon season; (3) overestimates the seasonal precipitation accumulation by 11 to 88 percent in monsoon season and underestimates by 18 to 89 percent in the nonmonsoon season; and (4) either overestimates annual precipitation accumulation up to 28.2 percent or underestimates it up to 11.9 percent. A truncation of 57 to 72 percent of the total rainfall hours is observed in the Stage III data in the nonmonsoon season, which may be the main cause for both the underestimation of the radar rainfall accumulation and the lower conditional probability of radar rainfall detection in the nonmonsoon season. The study results indicate that the truncation caused loss of small rainfall amounts (events) is not effectively corrected by the real‐time rain gauge calibration that can adjust the rainfall rates but cannot recover the truncated small rainfall events. However, the truncation error in the monsoon season may be suppressed due to the larger rainfall rate and/or combined effect of overestimates by bright band and hail contaminations, virga, advection, etc. In general, improvement in NEXRAD performance since the monsoon season in 1998 is observed, which is consistent with the systematic improvement in the NEXRAD network. 相似文献
964.
Chao Qin Shaogui Yang Cheng Sun Manjun Zhan Rongjun Wang Huanxing Cai Jia Zhou 《Frontiers of Environmental Science & Engineering in China》2010,4(3):321-328
A solution of atrazine in a TiO2 suspension, an endocrine disruptor in natural water, was tentatively treated by microwave-assisted photocatalytic technique.
The effects of mannitol, oxygen, humic acid, and hydrogen dioxide on the photodegradation rate were explored. The results
could be deduced as follows: the photocatalytic degradation of atrazine fits the pseudo-first-order kinetic well with k = 0.0328 s−1, and ·OH was identified as the dominant reactant. Photodegradation of atrazine was hindered in the presence of humic acid,
and the retardation effect increased as the concentration of humic acid increased. H2O2 displayed a significant negative influence on atrazine photocatalysis efficiency. Based on intermediates identified with
gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography-mass spectrometry (LC-MS/MS) techniques, the main degradation
routes of atrazine are proposed. 相似文献
965.
Xiaodong Wang Boqiang Qin Guang Gao Yongping Wang Xiangming Tang Timothy Otten 《环境科学学报(英文版)》2010,22(10):1491-1499
To evaluate the response of phytoplankton from Lake Taihu to di erent types of nutrients, the phytoplankton responses were
measured after adding inorganic nitrogen (N) and phosphorus (P) or decomposed algal scum (Microcystis spp.) into the lake water.
Both types of nutrients promoted an increase in phytoplankton biomass as determined by chlorophyll a and algal wet weight. The
addition of decomposed algal scum resulted in a significantly greater phytoplankton response than the addition of inorganic N and P
alone. The dissolved inorganic N and P in the inorganic nutrient treatment were found not limit phytoplankton growth. The higher algal
biomass obtained in the treatment with decomposed algal scum indicated the importance of other organic nutrients besides N and P
such as trace elements, as well as the importance of the form of N since the levels of ammonia nitrogen (NH4
+-N) from the decomposed
algal treatment were actually higher than that of the inorganic N and P addition. Microcystis spp. (Cyanobacteria), Scenedesmus spp.
(Chlorophyta) and Synechocystis spp. (Cyanobacteria) were the dominant taxa in the control, inorganic N and P treatment, and the
decomposed algal scum treatment, respectively. Microcystis never bloomed in response to both types of nutrient additions indicating
that the bloom propagation is not solely related to nutrient additions, but may be related to the absence of selective grazing from
zooplankton. 相似文献
966.
代琴 《安全.健康和环境》2010,10(4):25-27
针对屋顶太阳能热水器的安全隐患、产生原因进行了分析,提出相应的防护措施,避免设备、人员受到危害。 相似文献
967.
陆上石油天然气钻井是一个多工种、多工序、立体交叉、连续作业的系统工程。在钻井施工的各个阶段和各个环节中,特殊作业繁多,安令管理难度大,事故发生率相对较高,存在着不同程度、形式各异的风险,是石油行业中的一个高危作业。其中最易发生的事故有:机械伤害、物体打击、起重伤害、高处坠落、触电、中毒等人身伤害事故,特别是一旦发生井喷失控和火灾爆炸事故,将严重危及人民群众的生命安全. 相似文献
968.
随着环境监测机构实验室认可这项工作的深入开展,作为质量管理体系文件化直接产物的质量档案工作被推向了质量管理体系运行和认证的前沿,结合实验室资质评审工作,阐述了环境监测机构建立与管理质量控制档案的重要性:介绍了环境监测机构质量控制档案收集的内容和范围;论述了质量控制档案在环境监测机构质量体系运行、实验室认可、实验室内质量考核、实验室分析工作中的重要作用。 相似文献
969.
Preparation of organically functionalized silica gel as adsorbent for
copper ion adsorption 总被引:1,自引:0,他引:1
A novel adsorbent (AMPS-silica) was synthesized by bounding AMPS (2-acrylamido-2-methylpropanesulfonic acid) onto silica
surface, which functioned with
-methacryloxypropyltrimethoxysilane reagent. The adsorbent was characterized by nitrogen adsorption/
desorption measurement, thermogravimetric analysis (TGA) and potentiometric titration analysis. The TGA result indicated that
the surface modification reactions introduced some organic functional groups onto the surface of silica. The surface area of AMPSsilica
was 389.7 m2/g. The adsorbent was examined for copper ion removal in series of batch adsorption experiments. Results showed
that the adsorption of Cu2+ onto AMPS-silica was pH dependent, and the adsorption capacity increased with increasing pH from 2 to 6.
The adsorption kinetics showed that Cu2+ adsorption was fast and the data fitted well with a pseudo second- order kinetic model. The
adsorption of Cu2+ onto AMPS-silica obeyed both Freundlich and Langmuir isotherms, with r2 = 0.993 and r2 = 0.984, respectively.
The maximum Cu2+ adsorption capacity was 19.9 mg/g. The involved mechanism might be the adsorption through metal binding with
organic functional groups such as carboxyl, amino and sulfonic groups. Cu2+ loaded on AMPS-silica could be desorbed in HNO3
solution, and the adsorption properties remain stable after three adsorption-desorption cycles. 相似文献
970.
全球汞污染回顾与分析 总被引:7,自引:0,他引:7
回顾全球所经历的主要汞污染事件,引述国外科研工作者对全球汞污染与汞排放的调查和研究成果,重点介绍金矿开采对环境的污染与危害,揭示造成亚马逊流域汞污染的深层根源。分析今后全球防止汞污染的主要措施:一是主要工业化国家将进一步研究和改善工业领域相关行业的工艺技术水平,趋向无汞产品和无汞工艺,以减少自身的汞污染与排放;其二,发达国家陆续立法禁止汞的自由贸易和出口。发达国家对汞的出口限制将促使发展中国家相关行业(特别是小金矿)采取汞的替代工艺,从而减少全球性汞污染与排放。 相似文献