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1.
随着锂离子电池(LIBs)在便携式电子设备和电动汽车领域的广泛应用,未来势必会产生大量的废弃LIBs,如果处理不当,将会带来安全隐患;此外,电池的大量生产会消耗许多稀缺贵金属资源。由此可见,废弃的LIBs对环境保护和资源回收都造成了巨大压力。鉴于环境、资源、安全和回收问题,废旧LIBs的回收迫在眉睫。本文对LIBs阴极材料的回收路线进行了详细描述,列举了当前主要的阴极材料回收方法,包括湿法冶金、直接再生、火法冶金和机械化学法。其中机械化学法因具有安全清洁,反应效率高,能耗低等优点在众多的回收方法中脱颖而出,故重点综述了机械化学法回收废旧LiCoO(2 LCO), LiNixCoyMnzO(2 LNCM)和LiFePO(4 LFP)等阴极材料的研究进展。本文为回收废旧LIBs阴极材料提供了安全有效的思路,有助于推动机械化学法回收阴极材料向工业化发展。  相似文献   

2.
Describes factors that led the author to move his field of interest from laboratory social psychology to the emerging field of environmental psychology. Environmental psychology is defined as the attempt to establish empirical and theoretical relationships between the behavior and experience of the person and the built environment. The writer points up his dissatisfaction with the laboratory approach and the need to find a new methodology focused on complex environmental problems. Five methodological requirements for research in environmental psychology are described: the absolute integrity of person-physical-setting events; the distinction between behavior system reactions and psychological system reactions; a content orientation to problems; the time orientation of environmental psychology; and a context orientation in the analysis of problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
In addition to many types of extra cellular matrix (ECM) in vivo, cells are stimulated by many types of vitamins, hormones, growth factors, etc. In this paper the effects of L-ascorbic acid 2-phosphate (Asc-2P) and dexamethasone (Dex) on proliferation and differentiation of human periodontal ligament fibroblast (HPLF) using polyelectrolyte complex (PEC) as a matrix in vitro will be discussed. The PEC was composed of chitosan as a polycation, with carboxymethyl (CPEC) or sulfated chitin (SPEC). Asc-2P (0.2 mM) inhibited the growth of HPLF on CPEC, but promoted the growth on SPEC. Moreover, the aggregation of HPLF on CPEC was inhibited by Asc-2P, but that on SPEC was induced in the presence of Asc-2P and Dex. Although Asc-2P reduced an increase in alkaline phosphatase (ALPase) activity of HPLF on CPEC as well, it induced a twofold increase in ALPase activities on SPEC and TCD. Furthermore, in the medium containing Asc-2P and 100 mM of Dex, cell growth was inhibited, but ALPase activity was promoted on both SPEC and TCD to form many aggregates on SPEC. ALPase activity increased by twofold over that of HPLF cultured in the medium containing only Asc-2P. Therefore, it is suggested that the cell functions of HPLF are controlled by the combination of PEC and additives.  相似文献   

4.
挥发性有机污染物(VOCs)大量排放导致的人体健康和环境问题已引起广泛关注,如何高效环保地去除VOCs一直是催化化工行业领域的热点和难题之一.光催化氧化技术(PCO)被认为是有效的环境污染物治理方法之一.TiO2作为研究时间最长的光催化剂,具有成本效益高、稳定性好和光催化降解能力强等优点.然而,无法利用可见光和光激发电荷载流子分离效率低等瓶颈问题始终制约着其进一步发展.通过改性来克服TiO2固有限制和提高TiO2光催化氧化降解VOCs能力势在必行,立足于TiO2光催化去除VOCs的基本原理,面向影响光催化反应的关键因素,从掺杂、半导体复合、缺陷工程、晶面工程、载体吸附和形貌调控等几个方面出发对近年TiO2基材料设计及其在光催化降解VOCs领域应用的研究进行了系统的归纳和总结,并对如何进一步改进基于TiO2的光催化氧化VOCs技术提出展望.  相似文献   

5.
Development in sensitive watersheds continues to pose environmental problems for receiving waters. One contributor to this long-term pollution is building and other construction materials. However, the long-term effect of many building materials on the environment has not been quantified due to limited testing of these materials prior to sales and installation. Laboratory “leach” testing of commercially available roofing materials by this research group indicated that the potential for release (primarily nutrients, lighter hydrocarbons, pesticides, and metals) is substantial. Testing of metals’ release from aged roofing panels also has shown that the potential for pollutant release still exists after 60?years. The data missing from a complete evaluation of many roofing materials is behavior over the lifespan of the material, including the critical period of initial exposure. The 2?years of runoff data from a pilot-scale testing of these materials indicated substantial concerns regarding zinc from uncoated galvanized metals and copper from treated woods in this early part of the materials’ lifespan, plus the potential for long-term nutrient releases in the runoff from several roofing types.  相似文献   

6.
The factors involved in analytical quality relate to definition of quality, creation of quality, and control of quality, and errors arise from external and internal sources as well as from permanent and variable factors. Further, the two main types of error are classified as systematic and random errors. Internal quality control (IQC) systems can only operate on the variable factors which are related to batch-to-batch variations (external factors) and to the performance in the laboratory (internal factors). In creating an adequate internal control system, several problems are faced: (i) quality of control materials, (ii) types and frequency of possible errors, (iii) number and types of control materials, (iv) number of replicates of the control, (v) probability of error detection, (vi) probability of false rejection, (vii) consequences of reject signals, (viii) trouble-shooting systems, and (ix) prevention of errors among many other conditions. Gaussian distributions of control results are assumed and the statistical control rules are evaluated in relation to probability of false rejections, Pfr, and probability of error detection, Ped, for the different rules. Combinations of low Pfr and high Ped are obtained by combining results from e.g. four measurements of the same control sample by use of mean and range rules. Further, it is not possible to establish a common control system which can be used for all quantities and analytical procedures; on the contrary, each procedure should have its particular efficient IQC system. These aspects are discussed and a number of guidelines for statistical control rules and problem related internal quality control are presented.  相似文献   

7.
The configuration of blastoderm-heart cell aggregates after cell sorting depended largely on the proportion of each cell type initially present in the culture. In heterotypic aggregates, blastoderm cells were always found to partially or completely surround heart cells with both cell types retaining their characteristic morphology. Specialized junctions (e.g. desmosomes) developed only between cells of the same type. These observations suggest that blastoderm cells are unable to recognize and form stable contacts with heart cells.  相似文献   

8.
The energy challenge is central to the most important strategic problems facing the United States and the world. It is increasingly clear that even large-scale deployments of the best technologies available today cannot meet the rising energy demands of a growing world population. Achieving a secure and sustainable energy future will require full utilization of, and substantial improvements in, a comprehensive portfolio of energy systems and technologies. This goal is complicated by several factors. First, energy strategies are inextricably linked to national security and health issues. Second, in developing and deploying energy technologies, it is vital to consider not only environmental issues, such as global climate change, but also economic considerations, which strongly influence both public and political views on energy policy. Third, a significant and sustained effort in basic and applied research and development (R&D) will be required to deliver the innovations needed to ensure a desirable energy future. Innovations in materials science and engineering are especially needed to overcome the limits of essentially all energy technologies. A wealth of historical evidence demonstrates that such innovations are also the key to economic prosperity. From the development of the earliest cities around flint-trading centers, to the Industrial Revolution, to today’s silicon-based global economy, the advantage goes to those who lead in exploiting materials. I view our challenge by considering the rate of innovation and the transition of discovery to the marketplace as the relationship among R&D investment, a skilled and talented workforce, business innovations, and the activities of competitors. Most disturbing in analyzing this relationship is the need for trained workers in science, technology, engineering, and mathematics (STEM). To develop the STEM workforce needed for innovation, we need sustainable, positive change in STEM education at all levels from preschool through postgraduate. Materials sciences can be a significant magnet in attracting students to STEM areas, and a focused effort is needed to ensure that it is included in STEM programs. From this effort will come the next generation of materials scientists and the innovations that will enable us to overcome the energy challenge.  相似文献   

9.
The energy challenge is central to the most important strategic problems facing the United States and the world. It is increasingly clear that even large-scale deployments of the best technologies available today cannot meet the rising energy demands of a growing world population. Achieving a secure and sustainable energy future will require full utilization of, and substantial improvements in, a comprehensive portfolio of energy systems and technologies. This goal is complicated by several factors. First, energy strategies are inextricably linked to national security and health issues. Second, in developing and deploying energy technologies, it is vital to consider not only environmental issues, such as global climate change, but also economic considerations, which strongly influence both public and political views on energy policy. Third, a significant and sustained effort in basic and applied research and development (R&D) will be required to deliver the innovations needed to ensure a desirable energy future. Innovations in materials science and engineering are especially needed to overcome the limits of essentially all energy technologies. A wealth of historical evidence demonstrates that such innovations are also the key to economic prosperity. From the development of the earliest cities around flint-trading centers, to the Industrial Revolution, to today’s silicon-based global economy, the advantage goes to those who lead in exploiting materials. I view our challenge by considering the rate of innovation and the transition of discovery to the marketplace as the relationship among R&D investment, a skilled and talented workforce, business innovations, and the activities of competitors. Most disturbing in analyzing this relationship is the need for trained workers in science, technology, engineering, and mathematics (STEM). To develop the STEM workforce needed for innovation, we need sustainable, positive change in STEM education at all levels from preschool through postgraduate. Materials sciences can be a significant magnet in attracting students to STEM areas, and a focused effort is needed to ensure that it is included in STEM programs. From this effort will come the next generation of materials scientists and the innovations that will enable us to overcome the energy challenge.  相似文献   

10.
从冷镀锌钢管给水管材的问题引出了现代新型的给水管材,并从管材的耐温耐压、线膨胀系数、导热性、抗水锤能力、价格、安装等多方面进行了比较分类,并对各种管材在建筑中的应用范围进行了归纳和总结。  相似文献   

11.
中国的地下空间工程规模越来越大。如何使地下空间工程在开挖、建造和服役期间最大限度的保持安全和稳定,是目前乃至将来必须重视的重要课题。在分析地下空间工程面临的主要问题的基础上,提出了地下空间工程服役安全的3个关键科学问题:多场耦合作用下结构体材料损伤劣化规律;循环动载作用下结构体的动态疲劳损伤特性;支护与围岩的相互作用。总结和评述了在此方面的相关研究工作和最新进展。最后从宏观上指出了地下空间工程未来的发展趋势和需要重点关注和加强的基础性研究工作。   相似文献   

12.
Although the effect of biodiversity on ecosystem functioning has become a major focus in ecology, its significance in a fluctuating environment is still poorly understood. According to the insurance hypothesis, biodiversity insures ecosystems against declines in their functioning because many species provide greater guarantees that some will maintain functioning even if others fail. Here we examine this hypothesis theoretically. We develop a general stochastic dynamic model to assess the effects of species richness on the expected temporal mean and variance of ecosystem processes such as productivity, based on individual species' productivity responses to environmental fluctuations. Our model shows two major insurance effects of species richness on ecosystem productivity: (i) a buffering effect, i.e., a reduction in the temporal variance of productivity, and (ii) a performance-enhancing effect, i.e., an increase in the temporal mean of productivity. The strength of these insurance effects is determined by three factors: (i) the way ecosystem productivity is determined by individual species responses to environmental fluctuations, (ii) the degree of asynchronicity of these responses, and (iii) the detailed form of these responses. In particular, the greater the variance of the species responses, the lower the species richness at which the temporal mean of the ecosystem process saturates and the ecosystem becomes redundant. These results provide a strong theoretical foundation for the insurance hypothesis, which proves to be a fundamental principle for understanding the long-term effects of biodiversity on ecosystem processes.  相似文献   

13.
以特级矾土、矾土刚玉、SiO2微粉、Al2O3微粉和水泥为主要原料,研究了颗粒形状、骨料与粉料的比例、微粉、水泥用量等对浇注料流动性的影响。结果表明:1)接近球形的颗粒可提高浇注料的流动性;2)当变化骨料与粉料的比例时,在实验范围内,随粉料含量增加,浇注料流动性提高;3)刚玉颗粒和细粉对浇注料流动性基本没有影响;4)浇注料流动性主要受微粉的影响。变化微粉和水泥的比时,随水泥含量增加,浇注料流动性降低;SiO2微粉比Al2O3微粉更有利于提高浇注料的流动性。  相似文献   

14.
Effects of a recent founder event on genetic diversity in wild populations of the fire ant Solenopsis invicta were studied, with particular attention given to the genetic sex-determining system. Diploid males are far more common relative to haploid males in introduced populations than in native populations of fire ants, and queens that produce diploid males account for a significantly larger proportion of the mated queens in introduced than in native populations. Differences between native and introduced populations in attributes of the mating systems (i.e., queen mating frequency or level of inbreeding) can be excluded as factors contributing to these different levels of diploid male production. Thus, we conclude that diploid males have increased in frequency in introduced populations because of a loss of allelic diversity at the sex-determining locus (loci). This loss of sex alleles has generated a substantial increase in the estimated segregational genetic load associated with production of sterile diploid males in introduced populations over the load in native populations. The loss of allelic diversity in the sex-determining system in introduced S. invicta is paralleled by a loss of electrophoretically detectable rare alleles at protein-encoding loci. Such concordance between these different types of markers is predicted because each of the many sex alleles present in the native populations is expected to be rare. Estimates of expected heterozygosity (Hexp) based on 76 electrophoretic loci do not differ significantly between the native and introduced fire ant populations, illustrating the lack of sensitivity of this measure for detecting many types of bottlenecks.  相似文献   

15.
Until recently public health was primarily focused toward the solution of urgent problems of sanitation and the contagious diseases. It was concerned with the many problems of environmental sanitation, such as providing safe milk and water supplies and providing adequate means of disposing of waste. It was concerned also with a wide range of problems related to the control of diphtheria, smallpox, typhoid, malaria, and other contagious diseases. This article reports on the status of public health today. The Committee on Social Science in Public Health has identified several specific action possibilities which seem most likely to yield significant, long-range results in achieving these objectives, and these objectives are outlined in this article. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
铀矿山尾矿库周边地下水在铀矿的风化、淋滤、渗漏等作用下,给地下水和人类带来长期的健康隐患。可渗透反应墙(PRB)作为一种原位修复技术,具有无动力运行、环境影响小和成本低等优点,已经在地下水污染修复中得到了应用。羟基磷灰石(HAP)因具有成本低、原料广泛、生物相容性等优点,成为去除地下水中铀废水的最具潜力介质材料。综述了羟基磷灰石在处理含铀废水中的影响因素,主要包括羟基磷灰石制备方法、改性方法,对含铀废水去除影响研究。并对羟基磷灰石除铀进行机理分析,包括羟基磷灰石形貌、铀溶液pH、共存阴离子等对铀的去除影响。羟基磷灰石(HAP)因具有成本低、原料广泛、生物相容性等优点,成为去除地下水铀的最具潜力介质材料。  相似文献   

17.
Pretreatment of ores to improve energy efficacy of grinding has been explored for decades. However, many of these techniques are still at developmental stages and a review has been presented in this paper to discuss the research journey and problems associated with commercialization of these techniques. This review reveals that a variety of stress-generating techniques have been used to treat the composition and morphology of particles to improve the grinding process. Grinding additives are used commercially successful technology while microwave pretreatment also has been successfully piloted. Newly developed techniques such as ultrasonics and electric disintegration have shown potential for success but the cost economics of these processes is still not as attractive as desired. Incipient techniques based on bio-milling, shock waves, and nuclear hold promise for the future. It is also expected that the technological advances around information technology, instrumentation, and energy science will help to solve techno-economic challenges associated with commercialization of the known technologies. Demand for energy-efficient grinding pretreatment methods will grow in the future considering the depletion of high-grade resources and stringent environmental constraints related to reject disposal.  相似文献   

18.
冯琦  王强  彭锋 《中国冶金》2018,28(6):71-74
不锈钢生产会产生大量的不锈钢除尘灰和酸洗污泥等含镍、铬固体废弃物,如若处理不当,不仅会导致大量镍、铬等资源的浪费,而且会造成严重的环境污染。目前,含镍、铬不锈钢尘泥资源化利用途径虽然较多,但无论是回收其中有价金属元素,还是生产水泥、陶粒、化工颜料和肥料等资源化利用,都存在一定的局限性。因此,展望未来不锈钢尘泥的资源化利用应以直接返生产工序循环利用为重点研究和发展方向。  相似文献   

19.
It is increasingly accepted that a broad range of drugs and environmental factors can give rise to lupus syndromes and other types of connective tissue disease syndromes. This chapter reviews the drugs and environmental agents reported during this past year. Considerable research efforts are now focused on understanding the possible mechanisms, particular specificities of the antibody responses, new patterns of antibody responses, and biochemical pathways. These potentially important contributors to the expression of disease are reviewed.  相似文献   

20.
Matrix metalloproteinases (MMPs) belong to the key enzymes of the proteolytic destruction of cartilage matrix during chronic rheumatic diseases. Our work focused on the inhibitory potential of the hydroxamate Ro 31-4724 on the activity of MMP-proteoglycanases as well as on the viability, morphology and proteoglycan metabolism of interleukin-1 (IL-1)-treated bovine articular cartilage explants. The in vitro activity of MMP-proteoglycanases as well as the release of proteoglycans from IL-1-treated cartilage explants were significantly and concentration-dependently inhibited by Ro 31-4724 tested at concentrations ranging from 1 nmol/l to 10 mumol/l. Histopathological evaluation of sections from cartilage explants treated with this drug revealed no microscopically discernible alterations, and did not show any cytotoxic effects of Ro 31-4724. In addition, Ro 31-4724 had no effect on the rate of proteoglycan biosynthesis by IL-1-treated cartilage explants and increased the percentage of newly synthesized proteoglycans to form macromolecular aggregates. In conclusion, Ro 31-4724 displayed MMP-proteoglycanase inhibitory activity both in vitro and ex vivo and proved to be not harmful to the morphology, viability and proteoglycan biosynthesis of bovine articular cartilage explants.  相似文献   

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