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11.
大地震在主破裂前往往行成地壳变形,高应力作用下进入峰值后的变形阶段,反映到地倾斜观测日均值曲线上,表现为固体潮形变趋势异常,这些异常能否指示远距离的地震,近年来不少研究者发现,远场前兆往往出现在对应力、应变变化反应灵敏的特殊构造部位。佳木斯台可能处于这种特殊的构造部位,对东北地区浅源地震短期前兆异常“场兆”的趋势性变化具有一定的意义。 相似文献
12.
《环境科学学报(英文版)》2023,35(4):459-469
A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation. It was demonstrated that Co3O4 phase was the main component in regulation. The combined results of X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of oxygen (O2-TPD), temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of ammonia/carbon dioxide (NH3/CO2-TPD) revealed that component regulation led to more oxygen vacancies and exposure of surface Co2+, lower surface basicity and optimized acidity, which were beneficial for adsorption of active oxygen species and activation of methane molecules, resulting in the excellent catalytic oxidation performance. Especially, the (3.5)LC-C (3.5 is Co-to-La molar ratio) showed the optimum activity and the T50 and T90 (the temperature at which the CH4 conversion rate was 50% and 90%, respectively) were 318 and 367°C, respectively. Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spectroscopy characterization, it was also found that the catalytic mechanism changes from the “Rideal-Eley” mechanism to the “Two-term” mechanism depending on the temperature windows in which the reaction takes place. Besides, the use of the “Flynn-Wall-Ozawa” model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy, further expanding the application scope of carbon-containing composites. 相似文献
13.
国内环境民间组织合法性初探 总被引:5,自引:0,他引:5
环境保护领域的"政府失灵"和"市场失灵"要求社会调整机制的引入.社会调整机制以市民社会理论和实践为基础,市民社会主要由保护公民权利和公民政治参与的民间组织构成.环境民间组织作为一类组织生存下去的首要问题是其合法性.本文从政治和法律两个方面,论述了国内环境民间组织的合法性及其不足,并对克服其合法性危机进行了有益思考,以期国内环境民间组织健康发展,弥补市场调整机制与政府调整机制在环境保护方面的不足. 相似文献
14.
随着国民经济的不断发展,工农业用水日益增长,但可供利用的水资源有限,使得供水与需水矛盾加剧。因此,对流域内或流域间的水库进行联合调度和管理,将有限的水资源统筹安排、挖掘潜力、充分发挥现有工程的效益、提高供水的保证程度即对水库实施优化调度很有现实意义。本文应用系统分析方法,建立了灌溉水库群优化调度的聚合分解(AD)模型,以保证在系统整体效益最优条件下得出各库的最佳运行策略,从而使水库的运行管理建立在科学的基础之上。 相似文献
15.
James V. Bonta Bruce Cleland 《Journal of the American Water Resources Association》2003,39(6):1481-1496
ABSTRACT: Quantifying natural variability, uncertainty, and risk with minimal data is one of the greatest challenges facing those engaged in water quality evaluations, such as development of total maximum daily loads (TMDL), because of regulatory, natural, and analytical constraints. Quantification of uncertainty and variability in natural systems is illustrated using duration curves (DCs), plots that illustrate the percent of time that a particular flow rate (FDC), concentration (CDC), or load rate (LDC; “TMDL”) is exceeded, and are constructed using simple derived distributions. Duration curves require different construction methods and interpretations, depending on whether there is a statistically significant correlation between concentration (C) and flow (Q), and on the sign of the C‐Q regression slope (positive or negative). Flow DCs computed from annual runoff data vary compared with an FDC developed using all data. Percent exceedance for DCs can correspond to risk; however, DCs are not composed of independent quantities. Confidence intervals of data about a regression line can be used to develop confidence limits for the CDC and LDC. An alternate expression to a fixed TMDL is suggested as the risk of a load rate being exceeded and lying between confidence limits. Averages over partial ranges of DCs are also suggested as an alternative expression of TMDLs. DCs can be used to quantify watershed response in terms of changes in exceedances, concentrations, and load rates after implementation of best management practices. 相似文献
16.
John H. Martin 《Journal of the American Water Resources Association》1997,33(4):741-753
ABSTRACT: On May 19, 1993, a jury in the U.S. District Court for the Western District of New York found Southview Farm and Richard H. Popp guilty of violating the Clean Water Act on five occasions. The violations were the result of storm water runoff from a site used for disposal of dairy cattle manure from an unpermitted concentrated animal feeding operation. The presiding District Court judge later dismissed the jury verdict, and subsequently a U.S. Court of Appeals for the Second Circuit reversed the dismissal. The Court of Appeals concluded that the discharges were not exempt as agricultural storm water discharges, and that the manure spreaders involved were point sources. Because the use of animal manures in crop production activities will result, unavoidably, in the discharge of some pollutants to adjacent surface waters, a rational and universally applicable basis is needed to determine when such discharges are point versus nonpoint source. Current statutes and regulations do not delineate clearly such a boundary. To address this lack of specificity, I propose that application rates be based on recommended crop nutrient needs. 相似文献
17.
18.
《中国安全科学学报》1996,(Z1)
中国科学技术协会五届二次全委会明年在京召开我会两名代表参加全会活动中国科协第五届全国委员会第二次会议将于1997年2月22日至24日在北京召开。我会副理事长、中国科协全国委员会委员程映雪教授作为正式代表,我会副秘书长、“中国安全科学学报”主编徐德蜀高... 相似文献
19.
More than 20000 handling manoeuvres in loading or unloading trailers in a large transportation company were observed. The aim of the study was to determine the frequency and nature of the incidents occurring whilst handling. The incidents were recorded and interpreted from a double perspective, namely as risk factors and as activity regulation factors. The study showed that on average, one incident occurred in every seven handling manoeuvres: 71% of them were related to the environment, and 29% to the activity. While numerous, the environment-related incidents were generally without consequences. In this respect, the activity incidents appeared more risky; also, the majority of these incidents occurred during the load positioning phase. The study also showed that loads are re-handled twice as often in unloading as in loading, the frequency of re-handlings varying widely from one handler to another. The reasons why so few of the observed incidents are reported in accident studies and their significance in the understanding of handling problems are discussed. 相似文献
20.
Frank A. Ward Thomas P Lynch 《Journal of the American Water Resources Association》1996,32(6):1127-1138
ABSTRACT: This paper presents an integrated optimal control model that optimizes economic performance of reservoir management in watersheds in which there are significant economic and hydrologic interdependencies. The model is solved using the General Algebraic Modeling System (GAMS). Results show that application of this model to New Mexico's Rio Chama basin can increase total system benefits over historical benefits by exploiting complementarities between hydroelectricity production, instream recreation, and downstream lake recreation. 相似文献