全文获取类型
收费全文 | 94篇 |
免费 | 9篇 |
国内免费 | 61篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 19篇 |
环保管理 | 12篇 |
综合类 | 89篇 |
基础理论 | 18篇 |
污染及防治 | 18篇 |
评价与监测 | 1篇 |
社会与环境 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 11篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 12篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 31 毫秒
141.
Reactively Compatibilized Cellulosic Polylactide Microcomposites 总被引:3,自引:0,他引:3
Birgit Braun John R. Dorgan Daniel M. Knauss 《Journal of Polymers and the Environment》2006,14(1):49-58
Poly(lactic acid) (PLA) possesses a suite of favorable material properties that are enabling its penetration into diverse
markets (e.g., as packaging material or textile fibers). In order to increase the range of applications for this material,
it is necessary to modify its properties and for certain applications, reduce its cost. The introduction of fibers into a
polymeric matrix is an established route towards property enhancement provided good dispersion and intimate interfacial adhesion
can be achieved. In addition, cellulosic microfibers are obtainable at low to moderate cost. In this study, reactive compatibilization
of cellulosic fibers with PLA is pursued. Hydroxyl groups available on the surface of cellulosic fibers are used to initiate
lactide polymerization. Various processing strategies are investigated: (1) blending preformed PLA with the fiber material,
(2) through a one-step process in which lactide is polymerized in the presence of the fibers alone, or (3) reactive compatibilization
in the presence of preformed high molecular weight polymer. The results show that materials prepared by simultaneous introduction
of lactide and preformed high molecular PLA at the beginning of the reaction possess superior mechanical properties compared
to composites made by either purely mechanical mixing or solely polymerization of lactide in the presence of fibers. The modulus
of materials containing 25% fibers which are prepared by reactive compatibilization of 30% preformed PLA and 70% lactide (30/70
P/L) improves by 53% compared to the homopolymer, whereas 36% reinforcement can be achieved upon purely mechanical mixing.
A further increase to 35% fiber loading leads to a reduction in modulus due to an excess in initiating groups. The same trend
was observed in systems containing 65% preformed PLA and 35% lactide (65/35 P/L) with an overall achievable reinforcement
that was slightly lower. 相似文献
142.
The floatability of seven plastics (POM, PVC, PET, PMMA, PC, PS and ABS) in the presence of methyl cellulose (MC) and separation of plastics mixtures were investigated in this paper. It was found that the seven plastics can be separated into three groups by using the wetting agent MC. Group one includes POM and PVC. They are depressed at very low MC concentrations. Group two, including PET, PMMA and PC, has an intermediate floatability. Group three (ABS and PS) has a high floatability. They are almost not depressed within the given MC concentration range. In order to understand the mechanism of selective flotation of plastics and the chemical conditioning process, surface chemical factors, such as wettability of plastics and surface tension of flotation medium, and gravity factors, such as particle density and shape, were studied. It was found that the depressing effect of MC on plastics is ascribed mainly to its adsorption on the plastics surfaces. The MC molecules absorbed on plastics expose some of their polar groups oriented towards the aqueous phase, hence making the plastics surfaces hydrophilic. In addition, flotation selectivity for the plastics is dominated not only by wettability of plastics, but also by particle size, density and shape. 相似文献
143.
酸析木素法处理造纸黑液的改进与应用 总被引:15,自引:0,他引:15
介绍了造纸黑液酸析木素法工艺的改进及治理工程。在常规酸析木素法的基础上,优化了各种工艺条件,提高了木素沉降、过滤效率,减少了木素过滤负荷,增加了均化的预处理功能。做为主设备的反应罐具有酸化、预热、絮凝、升温、沉降分层和固液分离等多种功能;反应罐中加热方式的改进,提高了热效率,减少了搅拌装置。 相似文献
144.
145.
目的 以绿色天然材料为原料,制备高效CO2缓蚀剂.方法 以植物乳杆菌为改性工具,采用生物法对纤维素纳米纤维进行改性,制备功能化的纳米材料.采用红外光谱对产物结构进行表征,使用失重测试和电化学测试相结合对碳钢在饱和CO2盐溶液中的缓蚀性能进行评价.结果 功能化的纤维素纳米纤维对碳钢的腐蚀具有明显的抑制作用.失重测试证实,当添加浓度达到10?4时,缓蚀效率可达到88.6%.极化曲线测试表明,改性后纳米缓蚀剂的作用机制属于混合抑制型,对阴极电荷的传递过程和阳极溶解过程均产生抑制作用,且纳米粒子在高过电位下会发生脱附.不同时间的电化学阻抗谱测试表明,纳米缓蚀剂的缓蚀作用在溶液中达到稳定的时间约8 h,明显长于传统的缓蚀剂.结论 功能化的纤维素纳米纤维是一种缓蚀性能优异的新型纳米缓蚀剂,它独特的组成结构使其能在金属表面吸附成膜.这种特殊的改性方法为缓蚀剂的绿色安全生产提供了新的思路. 相似文献
146.
垃圾堆肥接种固氮菌对堆肥含氮量的影响 总被引:9,自引:0,他引:9
探索了垃圾堆肥混合接种自生固氮菌和纤维素分解菌对堆肥含氮量的影响。实验证明,在固氮菌的作用下,堆肥的含氮量有一定提高,纤维素分解菌对固氮菌的生长有一定协同效应。 相似文献
147.
设计了一种适合于白腐菌Phanerochaete Chrysosporium处理漂白废水的活性炭-化学纤维固定膜反应器,探讨了菌膜生长时的营养条件和废水组成对处理效果的影响。在适宜的工艺条件下,废水的脱色率达60~90%,CODcr去除率在50%以上。 相似文献
148.
Zirconium-based materials are efficient adsorbent for aqueous phosphate removal. However, current zirconium-based materials still show unsatisfied performance on adsorption capacity and selectivity. Here, we demonstrate a zirconium hydroxide encapsulated in quaternized cellulose (QC–Zr) for the selective phosphate removal. Zirconium hydroxide nanoparticles were simultaneously generated in situ with the QC framework and firmly anchored in the three-dimensional (3D) cross-linked cellulose chains. The maximum P adsorption capacity of QC–Zr was 83.6 mg P/g. Furthermore, the QC–Zr shows high P adsorption performance in a wide pH range, generally due to the electrostatic effects of quaternized cellulose. The enhanced adsorption of P was also achieved in the presence of competing anions (including Cl?, NO3?, , ) and humic acid (HA) even at a molar ratio up to 20 levels. The column adsorption capacity of QC–Zr reached 4000 bed volumes (BV) at EBCT = 0.5 min as the P concentration decreased from 2.5 to 0.5 mg/L. Mechanism study revealed that both –N+(CH3)3 groups and zirconium hydroxide were involved in phosphate adsorption via electrostatic interactions between –N+(CH3)3 and phosphate, and the formation of zirconium hydrogen phosphate (Zr(HPO4)x). The 31P nuclear magnetic resonance (NMR) study implied that P surface–precipitated and inner–sphere complexed with zirconium hydroxide at a ratio of 3:1. 相似文献
149.
150.
采用相转化法将类脂包埋到醋酸纤维素(CA)中,制备出了具有对水中低剂量亲脂性有机污染物高效吸附去除的平板膜.以扫描电子显微镜观察了复合材料的结构形貌和表面特征.利用机械搅拌方式和超声方式对类脂进行分散的实验表明,超声对类脂的均匀分散具有强化作用.同时考察了铸膜温度(室温、0℃)对类脂分散的效果,表明低温有助于形成小的脂滴.另外,通过复合膜的红外谱图证实,类脂和CA属于物理混合,不会改变类脂的分子结构,从而不会影响类脂对亲脂性有机污染物的吸附性能.通过荧光分析法分析复合膜在正己烷溶剂中的稳定情况,表明类脂已被完好地包埋到膜中,因而在去除有机污染物的过程中不会从复合膜中渗出. 相似文献