首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   156篇
  免费   5篇
  国内免费   2篇
安全科学   18篇
废物处理   2篇
环保管理   7篇
综合类   59篇
基础理论   13篇
污染及防治   26篇
评价与监测   21篇
社会与环境   16篇
灾害及防治   1篇
  2025年   2篇
  2023年   2篇
  2022年   4篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   2篇
  2017年   2篇
  2016年   1篇
  2015年   4篇
  2014年   4篇
  2013年   10篇
  2012年   6篇
  2011年   18篇
  2010年   7篇
  2009年   10篇
  2008年   12篇
  2007年   9篇
  2006年   9篇
  2005年   8篇
  2004年   6篇
  2003年   5篇
  2002年   1篇
  2001年   3篇
  2000年   4篇
  1999年   3篇
  1998年   7篇
  1997年   4篇
  1996年   5篇
  1994年   5篇
  1993年   2篇
  1992年   4篇
  1990年   1篇
排序方式: 共有163条查询结果,搜索用时 0 毫秒
1.
人民生活水平的提高使人民对室内环境的舒适程度提出了更高要求,室内装饰织物的用量迅速增加,室内装饰织物在燃烧时会释放出大量有毒物质和热量,对人及环境构成了巨大危害.因此,研究装饰织物的燃烧特性非常重要.笔者利用热重-差热(TG-DTA)分析仪对纯棉、棉麻和腈纶这几种典型的装饰织物在不同的氧气浓度(10%,15%,21%)和升温速率(10K/min,30K/min)条件下进行了热重分析(TG)和差热分析(DTA)实验,研究了它们的燃烧特性,并着重进行了不同氧浓度下的对比研究,发现试样的燃烧分为两个阶段.建立了以一级反应模型为主的动力学方程,并得出了各阶段的动力学参数、表观活化能和频率因子.  相似文献   
2.
Vacuum evaporation consists in the boiling of a liquid substrate at negative pressure, at a temperature lower than typical boiling temperature at atmospheric conditions. Condensed vapor represents the so called condensate, while the remaining substrate represents the concentrate.This technology is derived from other sectors and is mainly dedicated to the recovery of chemicals from industrial by-products, while it has not been widely implemented yet in the field of agricultural digestate treatment. The present paper relates on experimental tests performed in pilot-scale vacuum evaporation plants (0.100 and 0.025 m3), treating filtered digestate (liquid fraction of digestate filtered by a screw-press separator). Digestate was produced by a 1 MWe anaerobic digestion plant fed with swine manure, corn silage and other biomasses. Different system and process configurations were tested (single-stage and two-stage, with and without acidification) with the main objectives of assessing the technical feasibility and of optimizing process parameters for an eventual technology transfer to full scale systems.The inputs and outputs of the process were subject to characterization and mass and nutrients balances were determined.The vacuum evaporation process determined a relevant mass reduction of digestate.The single stage configuration determined the production of a concentrate, still in liquid phase, with a total solid (TS) mean concentration of 15.0%, representing, in terms of mass, 20.2% of the input; the remaining 79.8% was represented by condensate. The introduction of the second stage allowed to obtain a solid concentrate, characterized by a content of TS of 59.0% and representing 5.6% of initial mass.Nitrogen balance was influenced by digestate pH: in order to limit the stripping of ammonia and its transfer to condensate it was necessary to reduce the pH. At pH 5, 97.5% of total nitrogen remained in the concentrate. This product was characterized by very high concentrations of total Kjeldhal nitrogen (TKN), 55,000 mg/kg as average.Condensate, instead, represented 94.4% of input mass, containing 2.5% of TKN. This fraction could be discharged into surface water, after purification to meet the criteria imposed by Italian regulation. Most likely, condensate could be used as dilution water for digestion input, for cleaning floor and surfaces of animal housings or for crop irrigation.The research showed the great effectiveness of the vacuum evaporation process, especially in the two stage configuration with acidification. In fact, the concentration of nutrients in a small volume determines easier transportation and reduction of related management costs. In full scale plants energy consumption is estimated to be 5–8 kWhe/m3 of digestate and 350 kWht/m3 of evaporated water.  相似文献   
3.
通过实验研究了不同类型喷头对灭木垛火的影响。实验采用了ZSTX和ZSTP两种类型喷头,在不同的水压力下灭木垛火,通过实验现场观测和测得的烟气温度,烟气组分变化来分析对比灭火的效果和对烟气的影响。通过对比分析实验数据,可知ZSTX喷头在0.2MPa的水压力下可以实现灭火,ZSTP喷头在0.4MPa才可以实现灭火。喷淋实现灭火时产生的CO比只能实现控火产生的CO少。  相似文献   
4.
基于Fluent对压缩空气泡沫在长距离管道中的流动特性进行了数值模拟研究,将压缩空气泡沫近似为弥散流,采用Saplart-Allmaras模型模拟了不同管径下压缩空气泡沫以及不同泡沫原液浓度的AFFF泡沫在长距离管道内的流动及压降变化。模拟结果表明,随着距离变化,各管径管道内压降均呈现线性变化,且随着压缩空气泡沫的流动,压降线性增大。管道管径对管内压降变化具有显著影响,管道直径越小,管道内压降越大;泡沫原液浓度对压降的影响较小,且压缩空气泡沫在长距离输送中的压力随距离线性衰减。将模拟结果与长距离输送的试验结果进行了对比,误差在10%以内。  相似文献   
5.
    
There is a clear difference between exiting data on the measured flammability limits of hydrogen-air mixture. The non-uniformity of concentration distribution of hydrogen in air is a contributor to deviations of the upper flammability limit (UFL) and the lower flammability limit (LFL) measured in different experiments. This paper presents a numerical model to simulate the gas mixing process from start to stability, to predict the concentration distribution, and to research the influence of concentration distribution of hydrogen in air on measured UFLs and LFLs. The commercial software package Fluent was used to carry out the numerical simulation for the concentration distribution of hydrogen in air in the vessels with length-to-diameter ratios (L: D) of 1:1, 3:1, 5:1 and 7:1 respectively. Based on the numerical simulation and analysis, the influence of concentration distribution on measured flammability limits was demonstrated for hydrogen in air in the vessel. It is found that the deviations of measured flammability limits of hydrogen in air are the minimum in the vessel with length-to-diameter ratio of 1:1, and augment with the augmentation of vessel length-to-diameter ratio. Moreover, it is presented that the deviations of measured flammability limits of hydrogen in the center of the vessel are lower than that in the top and the bottom.  相似文献   
6.
在实测数据的基础上,以邻苯二甲酸酯(PAEs)的各类影响因素为自变量,PAEs浓度为因变量,采用Back-propagation(BP)神经网络建立儿童卧室内PAEs浓度预测模型.结果表明,该模型的预测效果较理想,其中,STD比值均>0.5,NMB均接近0,EMR均<19%.以室内环境与儿童健康(CCHH)课题组天津地...  相似文献   
7.
高温热表面油液蒸发的时变性热质传递模型与实验研究   总被引:1,自引:0,他引:1  
针对高温热表面油液蒸发热质传递过程的时变性,考虑这一过程中的对流传质传热,建立了热环境作用下油液蒸发的热质传递模型方程,通过无量纲变换,求得空间浓度分布和温度场随时间的变化规律。以庚烷为试验对象,对高温热表面油液蒸发过程进行了实验研究。理论分析与实验表明:庚烷蒸发过程中,刘易斯数大于1,传热速率大于传质速率;蒸发导致的质量损失与时间平方根的成正比,与液面的面积成正比,且与质量扩散系数的平方根成正比,饱和蒸气浓度越大,蒸发速率也越大。油液蒸发计算结果与试验结果基本一致,表明了模型的有效性。  相似文献   
8.
药厂、啤酒厂等有机废水厌氧处理试验研究   总被引:2,自引:0,他引:2  
针对几种高浓度有机废水进行厌氧处理试验,取得参数,为生产性试验提供有价值的参数。  相似文献   
9.
The current research provides guidance on the prevention and mitigation of dust explosion using a Quantitative Risk Management Framework (QRMF). Using concepts drawn from previous studies, the framework consists of three main steps: (i) a new combined safety management protocol, (ii) the use of DESC (Dust Explosion Simulation Code) and FTA (Fault Tree Analysis) to assess explosion consequences and likelihood, respectively, and (iii) application of the hierarchy of controls (inherent, engineered and procedural safety). QRMF assessment of an industrial case study showed that the original process was at high risk. DESC simulations and Probit equations determined the destructive percentages. FTAs revealed high probabilities of explosion occurrence; in addition, detailed individual and societal risks calculations were made, before and after the framework was applied. Based on the hierarchy of controls technique, the framework showed significant risk reduction to the point where the residual risk was acceptable for the process.  相似文献   
10.
系统介绍用计算机辅助确定矿井外因火灾位置方法的原理,给出该方法的具体步骤,剖析其定性分析、定量分析和定量分析结果评价三大步骤中的各技术关键,并借助一个实例验证了该方法实用的可行性  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号