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551.
552.
Moon Seong Rang Min Goo Kang Seung Woo Park Jeong Jae Lee Ryung Hak Yoo 《Journal of the American Water Resources Association》2006,42(2):473-486
The main focus of this study was to compare the Grey model and several artificial neural network (ANN) models for real time flood forecasting, including a comparison of the models for various lead times (ranging from one to six hours). For hydrological applications, the Grey model has the advantage that it can easily be used in forecasting without assuming that forecast storm events exhibit the same stochastic characteristics as the storm events themselves. The major advantage of an ANN in rainfall‐runoff modeling is that there is no requirement for any prior assumptions regarding the processes involved. The Grey model and three ANN models were applied to a 2,509 km2 watershed in the Republic of Korea to compare the results for real time flood forecasting with from one to six hours of lead time. The fifth‐order Grey model and the ANN models with the optimal network architectures, represented by ANN1004 (34 input nodes, 21 hidden nodes, and 1 output node), ANN1010 (40 input nodes, 25 hidden nodes, and 1 output node), and ANN1004T (14 input nodes, 21 hidden nodes, and 1 output node), were adopted to evaluate the effects of time lags and differences between area mean and point rainfall. The Grey model and the ANN models, which provided reliable forecasts with one to six hours of lead time, were calibrated and their datasets validated. The results showed that the Grey model and the ANN1010 model achieved the highest level of performance in forecasting runoff for one to six lead hours. The ANN model architectures (ANN1004 and ANN1010) that used point rainfall data performed better than the model that used mean rainfall data (ANN1004T) in the real time forecasting. The selected models thus appear to be a useful tool for flood forecasting in Korea. 相似文献
553.
554.
2002年5月1日,《职业病防治法》正式实施。《职业病防治法》的立法宗旨和核心内容是保护劳动者的健康及其相关权益。劳动者职业卫生保护权利劳动者的职业卫生保护权利,是指劳动者在就业或者从事职业活动中为了保护自身健康不受职业病危害,有权作为或者不作为的行为,也包括要求用人单位作为或者不作为的行为。根据职业病防治法第三十六条规定,劳动者享有以下职业卫生保护权利: (一)接受职业卫生教育、培训的权利劳动者有权要求用人单位对其进行上 相似文献
555.
556.
红外光谱法测定粉尘中游离二氧化硅综述 总被引:1,自引:1,他引:0
全面地回顾了国内外红外光谱法测定粉尘中游离二氧化硅的研究成果。系统而重点地介绍了溴化钾压片法、粉尘滤膜样品重沉积和采样滤膜直接测定技术,分析了样品粒度、标准石英物质和矿物干扰物对测定结果的影响及干扰消除方法;还介绍了国外对红外光谱法与X-射线衍射法进行比较性研究的结果和动态,并得出结论。文章所列参考文献对本领域研究人员和基层检测人员具有很高的参考价值。 相似文献
557.
558.
邓民宪 《防灾减灾工程学报》1999,(2)
根据震害调查分析和试验研究结果,建立了由环境因素和管道结构参数组成的,对架空管道震害预测进行二级多因素模糊综合评判的方法。文中给出了计算、评价构成二级评判因素地震烈度、场地类型、工作状态和结构种类各档次正态模糊数范数ak的参数和对实际情况如何确定的方法。本文为面广量大的已建架空管道的震害预测工作提供了一套科学性强,方便实用的计算方法。 相似文献
559.
Effect of surfactants on solubilization and degradation of phenanthrene under thermophilic conditions 总被引:1,自引:0,他引:1
The bioavailability and biodegradation of polycyclic aromatic hydrocarbons (PAHs) can be increased through the addition of surfactants. Previous studies of this nature have been conducted under mesophilic conditions. Hence, the aim of the present study was to investigate the effects of synthetic surfactants and biosurfactants on solubilization and degradation of phenanthrene (PHE) in a series of batch solution experiments under thermophilic conditions. Tween 80, Triton X-100, and biosurfactants produced from Pseudomonas aeruginosa strain P-CG3 (P-CG3) and Pseudomonas aeruginosa ATCC 9027 (P. 9027) were used in this study. Surfactants effectively enhanced the solubility of PHE at 50 degrees C and the biosurfactant from P-CG3 was most effective with a 28-fold increase in apparent solubility of PHE at a concentration of 10 x critical micelle concentration (CMC) compared with the controls. However, addition of synthetic surfactants or biosurfactants inhibited the biodegradation of PHE in mineral salts medium by an isolate Bacillus sp. B-UM. Degradation of PHE diminished with increasing surfactant concentrations, and PHE degradation was completely inhibited for all the surfactants tested when the concentrations were greater than their respective CMC. The growth test suggested that Tween 80 and biosurfactants were degradable, but preferential utilization of these surfactants as substrates was not the mechanism for explaining the inhibition of PHE biodegradation. Because of the hydrophobic property of B-UM, degradation inhibition of PHE by surfactants was probably due to the reduction of direct contact between bacterial cells and PHE. 相似文献
560.
Cao Junji Lee Shungcheng Zheng Xiangdong Ho Kinfai Zhang Xiaoye Guo Hai Chow Judith C. Wang Hongbin 《Water, Air, & Soil Pollution: Focus》2003,3(2):213-229
In April 1998, two intense dust storms were generated in CentralAsia and transported eastward across East Asia (15 and 19 April). This article presents the chemical characterization ofHong Kong (HK) aerosols during the dust storms. During the 15 Aprildust storm, hourly respiratory suspended particles (RSP)(particle diameter smaller than 10 m) concentrationsmonitored at 7 sites in Hong Kong reached the peak valuessynchronously between 9 and 11 a.m. on 17 April, in which thehighest concentration was 267 g m-3. Analysis ofthe RSP samples showed that concentrations of crustalelements (Ba, Ca, Cd, Cr, Fe, Mg, K+) and anthropogenicspecies (As, Ni, Pb, Zn, NH4
+, NO3
-,SO4
2- and total carbon) were substantiallyenhanced. Enhancement of these species was more than afactor of 2 to 14 relative to the non dust period. The totalcarbon content was high, at 59 g m-3 (notincluding carbonate), and the enrichment factors of Asand Pb on 17 April were 122 and 117, respectively. Thisimplied that anthropogenic materials together with mineraldust were transported to HK from Mainland China. Based onmaterial balance calculations, mineral dust contributed41% to the observed RSP mass on 17 April, which was 2 times thatof the nondust sample (22%). From the 5-day backwardtrajectory analysis, this storm was transported directlyfrom Northwest China to HK. However, there was nocorresponding observation for the 19 April dust stormaerosol. Consequently, 15 April storm had stronger impact onHK's atmosphere than 19 April storm. Compared to the HK AirQuality Objective, 15 April dust storm did not cause seriousair pollution in HK. 相似文献