全文获取类型
收费全文 | 306篇 |
免费 | 7篇 |
国内免费 | 34篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 14篇 |
环保管理 | 26篇 |
综合类 | 108篇 |
基础理论 | 32篇 |
污染及防治 | 51篇 |
评价与监测 | 18篇 |
社会与环境 | 1篇 |
出版年
2023年 | 11篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 16篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 27篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 5篇 |
2009年 | 16篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
排序方式: 共有347条查询结果,搜索用时 812 毫秒
301.
A series of medium-scale experiments on vented hydrogen deflagration was carried out at the KIT test side in a chamber of 1 × 1 × 1 m3 size with different vent areas. The experimental program was divided in three series: (1) uniform hydrogen–air mixtures; (2) stratified hydrogen–air mixtures within the enclosure; (3) a layer deflagration of uniform mixture. Different uniform hydrogen–air mixtures from 7 to 18% hydrogen were tested with variable vent areas 0.01–1.0 m2. One test was done for rich mixture with 50% H2. To vary a gradient of concentration, all the experiments with a stratified hydrogen–air mixtures had about 4%H2 at the bottom and 10 to 25% H2 at the top of the enclosure. Measurement system consisted of a set of pressure sensors and thermocouples inside and outside the enclosure. Four cameras combined with a schlieren system (BOS) for visual observation of combustion process through transparent sidewalls were used. Four experiments were selected as benchmark experiments to compare them with four times larger scale FM Global tests (Bauwens et al., 2011) and to provide experimental data for further CFD modelling. The nature of external explosion leading to the multiple pressure peak structure was investigated in details. Current work addresses knowledge gaps regarding indoor hydrogen accumulations and vented deflagrations. The experiments carried out within this work attend to contribute the data for improved criteria for hydrogen–air mixture and enclosure parameters to avoid unacceptable explosion overpressure. Based on theoretical analysis and current experimental data a further vent sizing technology for hydrogen deflagrations in confined spaces should be developed, taking into account the peculiarities of hydrogen–air mixture deflagrations in presence of obstacles, concentration gradients of hydrogen–air mixtures, dimensions of a layer of flammable cloud, vent inertia, etc. 相似文献
302.
One of conservation transfer methods for such widely-used gases as natural gas and hydrogen is buried pipelines. Safety of these pipelines is of great importance due to potential risks posed by inefficiencies of the pipelines. Therefore, an accurate understanding of release and movement characteristics of the leaked gas, i.e. distribution and speed within soil, the release to the ground surface, the movement of hydrogen gas through the ground, gas underground diffusion, gas dispersion in atmosphere, and following consequences, are very important in order to determine underground dispersion risks. In the present study, consequences of gas leakage within soil were evaluated in two sub-models, i.e. near-field and far-field, and a comprehensive model was proposed in order to ensure safety of buried gas supply pipelines. Near-field model which is related to soil and ground and its output is the gas released at different points and times from ground surface and it was adopted as input of far-field sub-model which is dispersion model in atmosphere or an open space under the surface. Validation of near-field sub-model was performed by the experimental data obtained by Okamoto et al. (2014) on full-scale hydrogen leakage and then, possible scenarios for far-field sub-model were determined. 相似文献
303.
Analytical models or abacus are of importance to predict explosion effects in open and congested areas for industrial safety reasons. The goal of this work is to compare overpressure and flame speed values of small-scale deflagration experiments to predicted values from the TNO multi-energy (TNO ME) method and the Baker-Strehlow-Tang (BST) method. Experiments were performed in cylindrical congested volumes of hydrogen – air mixtures varying from 1.77 L to 7.07 L. The reactivity was controlled by the equivalence ratio of hydrogen-air mixtures, ranging from 0.5 to 2.5. The congestion was realized with varying numbers of grid layers and configurations. The influence of the obstacle density and the importance of the mixture reactivity to choose the strength index in order to predict the effects of an explosion has been highlighted for the TNO ME method. Predictive flame speed values from the BST method are in accordance with almost half of the experimental results and the method is conservative in most tested configurations. The use of the TNO ME method has been validated on a small-scale experiment to predict maximal overpressures generated by the deflagration of medium and large-scale H2/air clouds. 相似文献
304.
新型聚乙烯填料生物滴滤床净化硫化氢气体运行特性 总被引:6,自引:3,他引:3
研究高密度聚乙烯改良型拉西环填料按其不同规格分层填充后生物滴滤床去除硫化氢气体的运行特性.126d的长期运行试验结果表明,该反应器具有压降低、负荷沿塔高分布均匀的显著优点.在去除率90%时,气体停留时间最短为12s,入口负荷最大为110g/(m3·h),反应器最大去除负荷为84g/(m3·h).底层去除比率在37%~55%之间,负荷在2层填料间分布均匀.整个长期运行期间反应器压降一直低于280Pa/m,反冲周期大于2个月,长期运行底层未发生生物量积累,稳定运行时压降的变化可以作为反应器反冲的监控指标.故障恢复试验表明,反应器在停止供应气相基质6d后,去除率恢复到95%仅需1d,喷淋液pH的剧烈变化对于反应器具有明显的不良影响. 相似文献
305.
The process of producing synthetic gas from waste plastics by steam reforming was investigated. To evaluate this process,
the steam reforming of the oils derived from low-density polyethylene and polystyrene were carried out using a laboratory-scale
fluidized bed of Ni-Al2O3 catalysts. The performance of gasification in terms of carbon conversion, gas yield, and gas compositions was examined. Although
oils derived from plastics contain many kinds of heavy hydrocarbons and aromatics, they were well gasified at temperatures
above 1023 K with a steam/carbon ratio of 3.5 and a weight hourly space velocity of 1 h−1. The hydrogen content of the product gas was very high at approximately 72 vol% for polyethylene-derived oil and 68 vol%
for polystyrene-derived oil. These compositions agreed well with the values calculated from chemical equilibrium. 相似文献
306.
Effect of ignition position on the run-up distance to DDT for hydrogen-air explosions 总被引:1,自引:0,他引:1
Robert Blanchard Detlef ArndtRainer Grätz Swen Scheider 《Journal of Loss Prevention in the Process Industries》2011,24(2):194-199
The method described in this paper enabled reliable and accurate positioning of an overdriven detonation by calculation of shock wave velocities (detonation and retonation) for hydrogen explosions in a closed 18 m long horizontal DN150 pipe. This enabled an empirical correlation between the ignition position and the run-up distance to DDT to be determined. It was shown that the initial ability of the flame to expand unobstructed and the piston-like effect of burnt gas expanding against the closed end of the tube contributed to initial flame acceleration and hence were able to affect the run-up distance to overdriven detonation. Flame speeds and rates of initial pressure rise were also used to explain how these two competing effects were able to produce a minimum in the run-up distance to DDT. The shortest run-up distance to DDT, relative to the ignition position, for this pipe and gas configuration was found when the ignition position was placed 5.6 pipe diameters (or 0.9 m) from the closed pipe end. The shortest run-up distance to DDT relative to the end of the pipe was recorded when the ignition source was placed 4.4 pipe diameters or 0.7 m from the pipe end. 相似文献
307.
Nanoparticles in mitigating gaseous emissions from liquid dairy manure stored under anaerobic condition 总被引:1,自引:0,他引:1
Niloy Chandra Sarker Shafiqur Rahman Md. Saidul Borhan Parthiban Rajasekaran Swadeshmukul Santr Ali Ozcan 《环境科学学报(英文版)》2019,31(2):26-36
A number of mitigation techniques exist to reduce the emissions of pollutant gases and greenhouse gases(GHGs) from anaerobic storage of livestock manure. Nanoparticle(NP)application is a promising mitigating treatment option for pollutant gases, but limited research is available on the mode of NP application and their effectiveness in gaseous emission reduction. In this study, zinc silica nanogel(ZnSNL), copper silica nanogel(CuSNL), and N-acetyl cysteine(NACL) coated zinc oxide quantum dot(Qdot) NPs were compared to a control lacking NPs. All three NPs tested significantly reduced gas production and concentrations compared to non-treated manure. Overall, cumulative gas volumes were reduced by 92.73%–95.83%, and concentrations reduced by 48.98%–99.75% for H_2S, and 20.24%–99.82% for GHGs. Thus, application of NPs is a potential treatment option for mitigating pollutant and GHG emissions from anaerobically stored manure. 相似文献
308.
Pierre-Franois Biard Annabelle Couvert Christophe Renner Jean-Pierre Levasseur 《Chemosphere》2009,77(2):182-187
Dimethyl disulphide (DMDS) removal was investigated in a compact scrubber (hydraulic residence time ≈20 ms), composed of a wire mesh packing structure where liquid and gas flow at co-current and high gas superficial velocity (>12 m s−1). In order to regenerate the scrubbing liquid and to maintain a driving force in the scrubber, ozone and hydrogen peroxide were added to water since they allow the generation of nonselective and highly reactive species, hydroxyl radicals HO. Three ways of reagent distribution were tested. The influence of several parameters (liquid flow rate(s), ozone flow rate, pH and reagent concentrations) was investigated. The best configuration was obtained when ozone is transferred in the scrubbing liquid before introduction at the top of the scrubber simultaneously with the hydrogen peroxide solution, allowing to generate hydroxyl radical in the scrubber. With this configuration, DMDS removal could be increased from 16% with water to 34% at the same gas and liquid flow rates in the scrubber showing the potentiality of advanced oxidation process. 相似文献
309.
310.
Stambuk-Giljanović N 《Environmental monitoring and assessment》2008,140(1-3):109-117
The objective of this paper is to study the hydrological characteristics and origin of the hydrogen sulphide spring water
from the Split spa in Southern Croatia in 1987, 1988 and 2003. This paper presents the results of monitoring the content of
chlorides and hydrogen sulphide as well as the temperature of the hydrogen sulphide spring water. Since the hydrogen sulphide
content during the dry periods significantly differs from the hydrogen sulphide content during rainy periods, this paper also
compares the results obtained for those two periods. Under the influence of great quantities of rainfall during cold periods
(winter and the beginning of spring) the ratio between seawater and surface water changes and thus the reduction of chlorides
and other minerals occurs. The lowered temperature also reduces hydrogen sulphide which can disappear completely. The concentration
of 12‰ chlorides (76–94.4% days/year) and 12 mg/L hydrogen sulphide (66.7–88.9% days/year) has been taken as a limit value
between water with a normal typical content and water in cold rainy periods. According to the monitoring results it can be
concluded that hydrogen sulphide spring water consists of seawater and hydrogencarbonate surface water with a fairly constant
content during dry periods while the hydrogencarbonate content increases during rainy periods. 相似文献