共查询到20条相似文献,搜索用时 406 毫秒
1.
提出了一种用于拉曼光谱测试的碳纤维截面和剖面样品的制备方法,采用拉曼光谱分别对国产JHT55、P278F和日本东丽T800S碳纤维的截面和剖面做成像扫描,通过比较碳纤维在各个维度上的石墨化程度,系统分析了其径向、轴向以及赤道方向的均一化程度。结果表明,3种T800级碳纤维均存在皮芯结构,轴向、赤道方向也有一定程度的不均匀性,东丽T800S整体的均一化程度远优于两种国产碳纤维。高度均质化是东丽T800S性能优于国产T800级碳纤维的重要原因。 相似文献
2.
3.
安全教育在高校实验教学中占有重要地位,国内很多高校开设了形式多样的安全教育课程,但多以文字形式为主,对学生而言相对枯燥,记忆不深刻,效果有限。为有效提高学生安全防范意识和能力,我们结合化学安全教育的特点,利用已有的物理化学实验,设计了一个立体化的典型安全教育实验,使之能适用于广泛的用途。 相似文献
4.
研究配合物的几何电子构型、阐明配位键的本质是配位化学中重要的理论组成部分。本文在回顾配位化学基本的成键理论基础上,介绍几例近年来具有教科书级别的国内高水平原创工作,重点阐述具有独特芳香性、低氧化态、高配位数以及锕系金属的新型金属配合物的电子结构和成键特点,对丰富和拓展配位化学的基本理论具有重要意义。 相似文献
5.
Jerzy Golimowski Agnieszka Tykarska 《Fresenius' Journal of Analytical Chemistry》1994,349(8-9):620-624
Methods of sampling an preparation of waste and compost samples for analysis are described. A voltammetric method has been used for the determination of the contents of toxic heavy metals (one of the most important criterion for compost quality evaluation) in domestic waste and in compost produced from it. A novel method was proposed for the UV mineralisation of water extracts obtained during leaching of waste and compost samples. Copper, lead, zinc and cadmium were determined in wet-digested samples of domestic waste, compost and its extracts by anodic stripping voltammetry. Nickel and cobalt were determined by adsorption voltammetry. The determination of five metals in one sample over a wide range of concentrations and the low cost of the apparatus used are the main advantages of the analytical method described. This has been shown by the determination of the metals in fractions of domestic waste, in compost produced of that waste and in compost mixed with sewage sludge. Special attention has been paid to investigations of the mobilisation of metals from waste and compost during the leaching test. 相似文献
6.
Paoletti Luigi Diociaiuti Marco Gianfagna Antonio Viviano Giuseppe 《Mikrochimica acta》1994,114(1):397-404
Fuel oil combustion in power plants, domestic heating systems and diesel engines, causes the emission in the environment of particles with a typical structure and composition: the cenospheres.These particles are produced during the microdrop fuel oil combustion, when air and fuel are injected into the combustion chamber; they have a spheroidal morphology and a spongy structure.Cenospheres are constituted by an amorphous component rich in C, S, Si, Fe and Al; phases composed by microcrystals of sulphates, oxides and pure metallic elements or their alloys, are frequently present in the cenospheres.These crystalline phases are important from environmental and toxicological points of view both because they are composed of heavy metals, and because they can play an important role in heterogeneous catalysis.We started to study these crystalline phases by analytical electron microscopy techniques and electron energy loss spectrometry to define and characterise their structure and composition. 相似文献
7.
8.
科学进步离不开科研仪器技术的发展, 科研仪器自主研制已成为我国促进技术创新的强劲动力和人才培养的重要平台. 飞船发射、航母制造、北斗导航等高科技重大突破离不开我国自行研制的高端科研仪器, 科技创新已成为当今各国提高综合国力的战略支撑. 每年我国对科研仪器的市场需求很大, 但进口仪器占比70%, 部分高端仪器更是100%依赖进口. 由于高、精、尖科研仪器的核心技术、关键零部件被国外封锁, 导致我国研发的高端科研仪器丧失国际竞争力. 针对上述现象, 通过对国产科研仪器目前现状分析, 就如何加强国家创新引导力来加快推进国产科研仪器高质量发展, 从而提升在国际市场的竞争力, 最终实现"进口替代"进行探讨. 相似文献
9.
手性和螺旋是生命体系中对生物功能起着重要作用的两大元素。近年来,由于螺旋状配合物特别是手性螺旋配合物被陆续发现在不对称催化、分子识别、手性拆分、非线性光学材料等方面存在较大的应用价值而备受化学家的关注。该文主要针对国内外已报道的手性螺旋配合物的组装方式进行分类总结,概括了手性螺旋配合物的主要构筑途径,包括:氢键作用、配位作用、π-π堆积以及亲银作用。 相似文献
10.
11.
Díaz-Ortiz A de la Hoz A Alcázar J Carrillo JR Herrero MA Fontana A Muñoz Jde M Prieto P de Cózar A 《Combinatorial chemistry & high throughput screening》2011,14(2):109-116
Organic reactions performed in the absence of solvent in domestic ovens without appropriate temperature control are generally considered as not reproducible, particularly when different instruments are used. For this reason, reproducibility has historically been one of the major issues associated with Microwave-Assisted Organic Synthesis (MAOS) especially when domestic ovens are involved. The lack of reproducibility limits the general applicability and the scale up of these reactions. In this work several solvent-free reactions previously carried out in domestic ovens have been translated into a single-mode microwave reactor and then scaled up in a multimode oven. The results show that most of these reactions, although not considered as reproducible, can be easily updated and applied in microwave reactors using temperature-controlled conditions. Furthermore, computational calculations can assist to explain and/or predict whether a reaction will be reproducible or not. 相似文献
12.
Cam Van T. Do Mai Huong T. Pham Thanh Yen T. Pham Cuc T. Dinh Thu Uyen T. Bui Thuan Dang Tran Van Tuyen Nguyen 《Current Opinion in Green and Sustainable Chemistry》2022
Domestic wastewaters are produced in huge volumes and abundant with carbon, nitrogen and phosphorous, which are a promising source of nutrients for production of microalgae. Microalgae-based bioremediation of domestic wastewater offers various advantages over traditional treatment approaches because the process consumes CO2, completely removes nitrogen and phosphorous for production of green biomass and oxygen. Moreover, the abundance of biochemical compositions (e.g., lipids, proteins, carbohydrates, bioactive compounds) of microalgae biomass is superior to terrestrial plant biomass in refining to multi-products having variety of commercial values. In this review, the most dominant microalgae used for simultaneous removal of pollutants and production of biomass and metabolites from domestic wastewater are presented. Biorefinery of microalgae biomass produced from domestic wastewater for production of multiple products is also explored. Finally, challenges and perspectives of successful microalgae-based bioremediation of domestic wastewater toward the biorefinery are briefly discussed. 相似文献
13.
Prof. Dr. Bartolo Gabriele Dr. Raffaella Mancuso Dr. Lucia Veltri 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5056-5094
Indanes and indenes are among the most important carbocycles. Many indane and indene derivatives have shown important pharmacological activities, and the indane and indene nuclei are structural motifs present in several natural products of biological relevance. In spite of their importance, only a few reviews on their preparation methods have appeared so far in the literature, the most recent ones being published about ten years ago. The present Review is aimed at filling this gap, presenting some of the most important and innovative approaches to indanes and indenes that have been published in the course of the last ten years (coverage: from 2005 to May, 2015). 相似文献
14.
15.
大气臭氧层破坏和CFCs替代物 总被引:15,自引:0,他引:15
CFCs 是与国民经济发展有关的重要化学材料。因为CFCs 破坏大气臭氧层,要限制它的使用并努力寻找它的替代物。研究和发展CFCs 替代物是有机氟化学的一个重要课题。 相似文献
16.
苯并菲盘状液晶是一类新型的有机电子学材料.该类材料多数以空穴传输功能为主,能传输电子的n-型材料较少.氮杂苯并菲是与苯并菲衍生物非常相似的一种杂环化合物,材料结构中引入了氮原子,吸电子能力得到增强,是潜在的n-型有机半导体材料,具有重要的应用价值.本文系统回顾了氮杂苯并菲类盘状液晶材料的研究进展,分类讨论了材料的分子结构,其中包括二、四、六氮杂苯并菲,以及它们的合成方法和物理化学性能,论述了材料在光电子领域的最新使用进展,并在此基础上,对该类液晶材料作为n-型有机半导体在光电子器件领域的应用前景进行了展望. 相似文献
17.
M. O. Pereira C. Calza M. J. Anjos R. T. Lopes F. G. Araújo 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):707-709
Summary The Paraíba do Sul River is located in a strategic region between the most important urban and industrial centers of Brazil.
In the last years, an increase in the water pollution has been reported, caused by the untreated domestic sewerage of the
inhabitants, effluents discharged by various industries, mining activities and sand extraction from the riverbed. This work
used total reflection X-ray fluorescence with synchrotron radiation (SRTXRF) to determine metals in the bioavailable and residual
fractions from the surface sediments. The metals identified were Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Ba and Pb. 相似文献
18.
G protein-coupled receptors (GPCRs) represent one of the most important categories of membrane proteins that play important roles in signaling pathways. GPCRs transduce the extracellular stimuli into intracellular second messengers via their coupling to specific class of heterotrimeric GTP-binding proteins (G proteins) and the subsequent regulation of a diverse variety of effectors. Understanding the coupling specificity of GPCRs is critical for further comprehending their function, and is of tremendous clinical significance because GPCRs are the most successful drug targets. This minireview addresses the computational approaches that have been created for the prediction of coupling specificity of GPCRs and highlights the perspective of bioinformatics strategies that may be used to tackle this important task. In addition, some of the important resources of this field are also provided. 相似文献
19.
Samuel C. Perry Sotirios Mavrikis Ling Wang Carlos Ponce de León 《Current Opinion in Electrochemistry》2021
Hydrogen peroxide (H2O2)is an important chemical with multiple uses across domestic and industrial settings. With a global need for wider adoption of green synthetic methods, there has been a growing interest in the electrochemical synthesis of H2O2 from oxygen reduction or water oxidation. State-of-the-art catalyst and reactor developments are beginning to advance to a stage where electrochemical synthesis is discussed as a viable alternative to current industrial methods. In this review, we highlight some of the most promising candidates for H2O2 electrosynthesis technologies and what further advancements are needed before the electrochemical route could challenge the ubiquitous anthraquinone process. 相似文献
20.
甲壳素/壳聚糖在环境治理上的应用 总被引:4,自引:0,他引:4
天然高分子化合物甲壳素、壳聚糖具有原料丰富、无毒、易于生物降解等优点,国内外众多学者对它的开发应用展开研究,本文综述了甲壳素、壳聚糖及其衍生物对环境污染物的去除,介绍了它在环境治理尤其是废水处理中的研究和应用情况。 相似文献