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411.
环境行政管理:集中抑或分散   总被引:1,自引:0,他引:1  
随着我国环境保护形势的变化 ,环境行政管理体制已对其缺乏适应性 ,并存在诸多问题 ,应进行环境行政管理模式的改革。为此 ,笔者联系世界各国的管理模式进行了分析和探讨 ,认为在横向管理权力地相对集中 ,纵向管理权力地相对分散的同时 ,建立各部门、各地区之间的协调机构的管理模式将是一种理性的选择。  相似文献   
412.
为研究雷电脉冲电流在导体表面的分布情况,研制了巨磁阻(Giant Magneto Resisti ve,GMR)表面电流测量系统,利用该系统对平面薄铝板表面脉冲电流密度进行了测量研究。为验证测量结果,采用时域有限差分(FDTD)法和CST软件分别进行了相应的数值分析和仿真计算,取得与测量相一致的结果。在此基础上,对雷电流在弧面表面分布情况进行了探索性研究。  相似文献   
413.
云南省丽江大地震及其诱发的崩塌滑坡灾害特征   总被引:21,自引:1,他引:21  
1996年2月3日,云南省丽江县城以北40km发生7级强烈地震,这次地震在约12000km2范围内诱发了至少420处中小型崩塌和30处大中型滑坡,造成房屋倒塌、桥梁毁坏和公路堵塞。调查研究得出以下结论:(1)地震触发的崩塌滑坡分布在Ⅵ度区内,主要集中在主震震中东南部,接近表层构造断裂带和余震活动范围内;(2)崩塌主要发生在高陡斜坡的峡谷地带,滑坡多为复活型,部分为同发型和滞后型滑坡;(3)地形是控制崩塌滑坡分布位置的主导因素,崩塌多发生于大于60度斜坡中上部,滑坡发育于中缓斜坡(25°~45°);(4)滑坡影响区如遇充足的降雨可能进一步变形破坏,大量地裂隙孕育着新的崩塌滑坡,潜在危险性大。  相似文献   
414.
The widespread contamination of water systems with antibiotics and heavy metals has gained much attention. Intimately coupled visible -light-responsive photocatalysis and biodegradation (ICPB) provides a novel approach for removing such mixed pollutants. In ICPB, the photocatalysis products are biodegraded by a protected biofilm, leading to the mineralization of refractory organics. In the present study, the ICPB approach exhibited excellent photocatalytic activity and biodegradation, providing up to ∼1.27 times the degradation rate of sulfamethoxazole (SMX) and 1.16 times the Cr(VI) reduction rate of visible-light-induced photocatalysis . Three-dimensional fluorescence analysis demonstrated the synergistic ICPB effects of photocatalysis and biodegradation for removing SMX and reducing Cr(VI). In addition, the toxicity of the SMX intermediates and Cr(VI) in the ICPB process significantly decreased. The use of MoS2/CoS2 photocatalyst accelerated the separation of electrons and holes, with•O2 and h+ attacking SMX and e reducing Cr(VI), providing an effective means for enhancing the removal and mineralization of these mixed pollutants via the ICPB technique. The microbial community results demonstrate that bacteria that are conducive to pollutant removal are were enriched by the acclimation and ICPB operation processes, thus significantly improving the performance of the ICPB system.  相似文献   
415.
Environmental Science and Pollution Research - The microwave electrodeless lamp UV photocatalysis (MWUV) integrated with iron carbon micro-electrolysis (ME) was applied to degrade reactive...  相似文献   
416.
Cashew nut shell liquid (CNSL) is a natural aromatic oil consisting of a mixture of phenolic structures with a carboxyl group in ortho position and substituted in meta position with a hydrocarbon chain of 15 carbon atoms. The major component of CNSL is anacardic acid (90?%), which is easily decarboxylated to cardanol by distillation. The present work describes the synthesis of new biobased Mannich polyols for rigid polyurethane foams in two steps: synthesis of Mannich bases by reacting phenolic ring of cardanol with N-(2-hydroxyethyl)-1,3-oxazolidine followed by alkoxylation reactions. The polyols were characterized by wet methods (hydroxyl numbers, viscosity, acid value, density, water content, iodine value etc.), spectroscopic methods (FT-IR, 1H NMR and 13C NMR) and by Gel Permeation Chromatography. The Mannich polyols from cardanol are excellent replacements for petrochemical derived Mannich polyols based on nonyl phenol. Cardanol-based polyols were used successfully for the preparation of rigid polyurethane foams of good physical?Cmechanical and fireproofing properties.  相似文献   
417.
为了研究车载接地问题,研制了可迅速安装和撤收的便携式接地模块。以多个接地模块组成十字型和一字型组合接地装置,模块之间用多芯铜绞线相连。利用接地实验系统对组合接地装置进行试验,同时对实验系统建模,采用时域有限差分法进行数值分析。通过对一字型和十字型接地装置进行实验研究及数值分析,得出两种组合接地装置的优劣。  相似文献   
418.
太阳能电池生产废水处理工程设计   总被引:1,自引:1,他引:0  
太阳能电池作为一种清洁能源,应用越来越广泛,然而其生产废水中因含有大量F-及酸碱物质,腐蚀性强,治理困难。采用石灰乳+CaCl2+PAC混凝沉淀工艺处理太阳能电池生产废水。工程设计规模为浓含氟废水7 m3/d、稀含氟废水200 m3/d、酸碱性废水200 m3/d、含IPA废水1 m3/d,经过3个多月的调试运行,出水中ρ(COD)≤500 mg/L,ρ(BOD5)≤300 mg/L,ρ(SS)≤400 mg/L,pH保持在6~9,ρ(F-)≤20 mg/L,达到GB 8978—1996《污水综合排放标准》三级标准。废水处理工艺紧凑,处理效果好、运行稳定、具有推广价值。  相似文献   
419.
含雄黄的中成药中砷的生物可给性及其初步风险评价   总被引:1,自引:0,他引:1  
为研究含雄黄中成药中砷的含量状况,探明其中砷对人体的健康风险,选取含雄黄的中成药为研究对象,分析其中砷含量;通过人工胃肠体外模拟系统研究中成药中砷的生物可给性,并在此基础上进行初步的人体健康风险评价。结果显示,含雄黄中成药样品中砷全量为9.9×102~8.8×104mg·kg-1。中成药砷的生物可给性在胃阶段为0.20%~2.17%,小肠阶段为0.26%~2.43%。以WHO每日允许摄入量(ADI)为标准的健康风险评价结果表明,若以砷全量衡量,所有含雄黄中成药均对人体健康具有巨大风险;若以小肠阶段可给砷含量评价,砷日摄入量与ADI比值范围为1.48%~879.68%,约70%含雄黄的中成药的可给砷含量仍足以威胁人体健康。  相似文献   
420.
A study was undertaken for the prediction of runoff flow from 0.8 ha field-sized agricultural watershed in South Korea using Soil and Water Assessment Tool (SWAT) sub-daily. The SWAT model with sub-daily configuration predicted flow from the watershed within the range of acceptable accuracy. The SWAT sub-daily simulations were carried out for a total of 18 rainfall events, 9 each for calibration and validation. Overall trend and extent of matching simulated flow for the rainfall events in 2007-2008 with measured data during the calibration process were coefficient of determination (R2) value of 0.88 and Nash and Sutcliffe Efficiency (ENS) value of 0.88. For validation, R2 and ENS values were 0.9 and 0.84, respectively. Whereas R2 and ENS values for simulation results using daily rainfall data were 0.79 and -0.01, respectively, that were observed to be out of acceptable limits for the model simulation. The importance of higher time resolution (hourly) precipitation records for flow simulation were evaluated by comparing R2 and ENS with 15 min, 2 h, 6 h and 12 h precipitation data, which resulted in lower statistics with increases in time resolution of precipitation data. The SWAT sub-daily sensitivity analysis was performed with the consideration of hydraulic parameter and was found as in the rank order of CN2 (curve number), ESCO (soil evaporation compensation factor), GW_DELAY (ground water delay time), ALPHA_BF ( base flow alpha factor), GWQMN ( a threshold minimum depth of water in the shallow aquifer required for return flow to occur) , REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur) , LAT_TIME (lateral flow travel time) respectively. These sensitive parameters were evaluated at 10% higher and lower values of the parameters, corresponding to 70.5% higher and 23.2% lower in simulated flow out from the SWAT model. From the results obtained in this study, hourly precipitation record for SWAT sub-daily with Green-Ampt infiltration method was proven to be efficient for runoff estimation at field sized watershed with higher accuracies that could be efficiently used to develop site-specific Best Management Practices (BMPs) considering rainfall intensity, rather than simply using daily rainfall data.  相似文献   
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