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   47篇
  免费   13篇
  国内免费   17篇
安全科学   13篇
废物处理   4篇
环保管理   8篇
综合类   28篇
基础理论   5篇
污染及防治   15篇
社会与环境   1篇
灾害及防治   3篇
  2023年   2篇
  2021年   3篇
  2019年   4篇
  2018年   3篇
  2017年   3篇
  2016年   1篇
  2015年   5篇
  2013年   6篇
  2012年   5篇
  2011年   8篇
  2010年   4篇
  2009年   5篇
  2008年   3篇
  2007年   3篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1995年   2篇
  1994年   2篇
  1984年   1篇
  1978年   1篇
排序方式: 共有77条查询结果,搜索用时 62 毫秒
31.
一种新型高铺展性水成膜泡沫的性质以及灭火性能研究   总被引:1,自引:0,他引:1  
介绍了一种自制的多组分水成膜泡沫溶液,并对该泡沫溶液的各种性能(表面张力,铺展性,灭火性能等)进行了表征,同时与传统的水成膜泡沫进行了对比.试验结果表明,该泡沫溶液的表面张力和界面张力很低.极低的表面和界面张力导致该泡沫在液体燃料表面具有很强的铺展性,能在极短的时间内在燃料表面铺展成一层液膜,使燃料表面迅速隔氧降温,从而达到迅速灭火的作用.在通过压缩空气泡沫系统进行灭火的试验中,不论泡沫浓度处于3%或6%,在液体流量较大的情况下,该泡沫对标准柴油火的熄灭时间都在3秒之内.另外,泡沫溶液的铺展性和所形成的泡沫的灭火性能的试验结果表明水成膜泡沫的灭火速率主要是由其在燃料表面形成水膜的速率决定,而形成水膜的速率主要是由泡沫溶液的铺展速率、即铺展性决定的.  相似文献   
32.
环烷烃/海水界面张力的研究   总被引:1,自引:0,他引:1  
作者已用滴体积法首次比较系统地测定了环已烷、环戊烷、甲基环已烷与海水的界面张力在不同温度(16 ̄36℃)和不同的海水盐度(0 ̄40)时之值,测定值相对误差约在0.5%以内。结果表明,在海水盐度恒定时,所研究的环烷烃/海水界面张力的温度系数为负值,而甲基环已烷/海水界面张力的温度系数为正值,这一异常现象有待今后作进一步理论探讨。环已烷、环戊烷与海水界面张力的盐度系数为正值,而甲基环已烷/海面水界面张  相似文献   
33.
用图论的方法研究了正烷烃,烷基苯及烷苯磺酸盐类表面活性剂分子的EACN值与分子结构间的关系。发现分子的EACN值与Wiener指数和极性数有良好的线性相关性。  相似文献   
34.
为了提高微细粉尘的除尘效果,将聚丙烯酰胺(PAM)与琥珀酸二辛酯磺酸钠(AOT)等进行复配,并分别测定了粉尘的沉降时间、溶液表面张力及其紫外吸收光谱。结果表明,AOT与PAM复配后,形成了新的物质,可降低溶液表面张力和粉尘沉降时间,从而提高微尘湿润效果。  相似文献   
35.
The immediate cost of shallow regolith landslides in New Zealand has been estimated to exceed US$33M annually. Since the majority of these landslides occur during prolonged wet conditions, or intense rainstorms, moisture conditions are a critical control. The nature, dynamics, and character of soil moisture conditions, and the piezometric response to rainfall, have been recorded within an ‘incipient’ landslide for more than 5 years. The study site, on pastoral hill country within the Lake Tutira catchment in northern Hawkes Bay, is typical of large areas of New Zealand episodically affected by extensive landsliding. Detailed continuous measurements show that both the soil moisture and piezometric response within the regolith are highly storm- and site-specific. The development of positive pore pressures is infrequent; they form only during intense rainstorms, and persist for a short time. The hydraulic response of the soil is primarily a function of storm characteristics, but this response can be modified by antecedent moisture conditions, topographic position, and heterogeneity of soil properties.  相似文献   
36.
宋丹丹  梁生康  王江涛 《环境化学》2011,30(8):1474-1479
通过摇瓶培养实验,考察了假丝酵母菌(Candida bombicola)ATCC 22214以葡萄糖和油酸双底物为碳源,采用一次加料培养和分批补料培养方式进行发酵制备槐糖脂的过程,并利用高效液相色谱/电喷雾飞行时间质谱联用仪确定了所产槐糖脂的结构,初步研究了其主要的理化性质.结果表明,一次加料培养中,该菌株生长稳定期的...  相似文献   
37.
通过测定液体与废白土粉末之间的接触角及液体与蜡之间的液液界面张力,对水基表面活性剂乳液的溶剂及配方进行了优选,得到最俊的水基表面活性剂乳液的组成为:质量分数0.2%的十二烷基苯磺酸钠十体积分数为2.5%的乙醇十体积分数为25%的混合烃(正己烷十苯,等体积)+体积分数为72.5%的水,实验证明,用该水基表面活性剂乳液处理废白土,蜡的回收率可达80%,同时不破坏白土的颗粒结构。  相似文献   
38.
唐庚  何张涵  王勇  王伟  王永军  段明 《化工环保》2012,40(3):315-321
以L-苯丙氨酸、长链烷基(C12/C14/C16/C18)酰氯和聚乙二醇单甲醚(MPEG,Mn=350,550,750,1 000 g/mol)为原料,合成了一系列新型非离子型表面活性剂N-长链碳酰基-L-苯丙氨酸单甲基聚乙二醇酯(Rn-L-MPEG),系统研究了表面张力、界面张力和土壤吸附性与其结构之间的关系。结果表明:随着MPEG分子量的增大,Rn-L-MPEG的表面张力逐渐下降;随着酰氯中烷基链的增长,Rn-L-MPEG的表面张力呈现增大趋势,系列表面活性剂中R12-L-MPEG1000具有最低的表面张力28.11 mN/m;Rn-L-MPEG的界面张力随分子结构变化的规律同表面张力;随着MPEG分子量的增大,Rn-L-MPEG的饱和吸附量逐渐增大,随着酰氯中烷基链的增长,Rn-L-MPEG的饱和吸附量呈现下降趋势。  相似文献   
39.
卢毅  陈家军  林婷 《环境科学》2010,31(1):205-210
醇类助溶剂单一使用及复配表面活性剂使用去除砂土中多氯联苯(PCBs)的关键是增溶和降低界面张力.通过降低界面张力实验和振荡增溶实验分析了醇类助溶剂单一使用对多氯联苯界面张力的降低作用和增溶作用,以及醇类复配Triton X-100使用时醇对Triton X-100降低界面张力和增溶PCBs的影响.结果表明,醇-PCBs油的界面张力与醇浓度、醇含碳原子数均呈负相关,甲醇、乙醇、异丙醇的最佳解吸浓度分别为70%、55%、40%,最佳解吸效率达90%以上;Triton X-100-PCBs油界面张力与Triton X-100浓度呈负相关,Triton X-100浓度低于3 000 mg/L时复配10%乙醇、10%异丙醇比单一Triton X-100振荡洗脱效率低,Triton X-100浓度在3 000~7 500 mg/L时3组差异不大,Triton X-100浓度为10 000 mg/L时单一、10%乙醇、10%异丙醇TritonX-100溶液解吸效率分别为80.9%、90.36%、89.36%.表明醇类单一使用对降低界面张力与增溶均有很好的效果,但需要其体积分数达40%以上;醇类复配Triton X-100时醇的存在弱化了Triton X-100增溶和降低界面张力的作用,乙醇与异丙醇弱化作用差异性不大,当Triton X-100浓度高于3 000 mg/L时,弱化作用不显著.  相似文献   
40.
Objective: To evaluate the influence of forward-facing child restraint systems’ (FFCRSs) side impact structure, such as side wings, on the head kinematics and response of a restrained, far- or center-seated 3-year-old anthropomorphic test device (ATD) in oblique sled tests.

Methods: Sled tests were conducted utilizing an FFCRS with large side wings and with the side wings removed. The CRS were attached via LATCH on 2 different vehicle seat fixtures—a small SUV rear bench seat and minivan rear bucket seat—secured to the sled carriage at 20° from lateral. Four tests were conducted on each vehicle seat fixture, 2 for each FFCRS configuration. A Q3s dummy was positioned in FFCRS according to the CRS owner's manual and FMVSS 213 procedures. The tests were conducted using the proposed FMVSS 213 side impact pulse. Three-dimensional motion cameras collected head excursion data. Relevant data collected during testing included the ATD head excursions, head accelerations, LATCH belt loads, and neck loads.

Results: Results indicate that side wings have little influence on head excursions and ATD response. The median lateral head excursion was 435 mm with side wings and 443 mm without side wings. The primary differences in head response were observed between the 2 vehicle seat fixtures due to the vehicle seat head restraint design. The bench seat integrated head restraint forced a tether routing path over the head restraint. Due to the lateral crash forces, the tether moved laterally off the head restraint reducing tension and increasing head excursion (477 mm median). In contrast, when the tether was routed through the bucket seat's adjustable head restraint, it maintained a tight attachment and helped control head excursion (393 mm median).

Conclusion: This testing illustrated relevant side impact crash circumstances where side wings do not provide the desired head containment for a 3-year-old ATD seated far-side or center in FFCRS. The head appears to roll out of the FFCRS even in the presence of side wings, which may expose the occupant to potential head impact injuries. We postulate that in a center or far-side seating configuration, the absence of door structure immediately adjacent to the CRS facilitates the rotation and tipping of the FFCRS toward the impact side and the roll-out of the head around the side wing structure. Results suggest that other prevention measures, in the form of alternative side impact structure design, FFCRS vehicle attachment, or shared protection between the FFCRS and the vehicle, may be necessary to protect children in oblique side impact crashes.  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