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   144篇
  免费   9篇
  国内免费   18篇
化学   109篇
晶体学   1篇
力学   11篇
综合类   2篇
数学   3篇
物理学   45篇
  2022年   8篇
  2021年   5篇
  2020年   12篇
  2019年   3篇
  2018年   5篇
  2017年   2篇
  2016年   8篇
  2015年   2篇
  2014年   2篇
  2013年   12篇
  2012年   7篇
  2011年   14篇
  2010年   10篇
  2009年   7篇
  2008年   6篇
  2007年   14篇
  2006年   5篇
  2005年   9篇
  2004年   6篇
  2003年   3篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1999年   6篇
  1998年   1篇
  1997年   3篇
  1996年   1篇
  1995年   3篇
  1994年   1篇
  1993年   5篇
  1992年   2篇
  1990年   1篇
  1986年   1篇
  1984年   1篇
排序方式: 共有171条查询结果,搜索用时 15 毫秒
11.
用激光诱导击穿光谱快速分析油漆中的重金属含量   总被引:5,自引:1,他引:5       下载免费PDF全文
 将电光调Q Nd:YAG激光脉冲聚焦于油漆样品表面以产生激光诱导等离子体。等离子体的光辐射经过一组透镜收集进入单色仪并由光电倍增管探测。通过对等离子体辐射光谱的研究,能够实现对油漆样品中重金属元素含量的快速定性分析。实验分析了多种市售油漆中重金属元素Pb, Cu, Cr, Mn的含量。实验表明:对于同一种类的油漆样品,在相同检测条件下,重金属元素的特征光谱线强度与元素质量分数成正比,因此利用激光诱导击穿光谱来快速分析油漆中重金属元素含量是完全可行的。  相似文献   
12.
Abstract

Marine fouling can be a serious problem in the shipping industry, since it increases the surface roughness of the hull and hence its frictional resistance to its movement through water. Antifouling paint can be defined as preventing the attachment of marine organisms onto surfaces. However, the most commonly used antifouling coating which is the tributyltin-based self-polishing copolymer causes the severe pollution of marine environment. Ammonium salt-based paints include tertiary amines as biocides which have effective biocidal and biodegradable properties without accumulation in the sea environment. However, ammonium salt-based coatings were too sensitive to seawater and became swollen. In this study, polyurethane-acrylic copolymers were synthesized by radical polymerization. These hybrid materials were found to form core–shell structures in aqueous media. Synthesis and properties of copolymers were investigated by Fourier transform-infrared spectrometer, proton-nuclear magnetic resonance, transmission electron microscopy, and dynamic light scattering. The polishing rate of self-polishing copolymer was determined from the reduction in dry film thickness after artificial seawater immersion under a dynamic condition.  相似文献   
13.
Pressure-sensitive paint (PSP) is a relatively new aerodynamic measurement tool with the unique capability of providing a field measurement of pressure over a test surface. An introductory review of this technology is presented, which is confined to the application of the PSP method to aircraft development wind tunnel testing. This is at present the primary application area and thus the focus of research on the use of the method, and is the authors' own area of research. Described are PSP fundamentals, the various elements comprising PSP technology, and current limitations and considerations in applying this technology. Experimental results are presented to illustrate the present capability of the method. The few publications currently available on this subject in the open literature are also referenced.  相似文献   
14.
云纹干涉制栅新技术   总被引:4,自引:0,他引:4  
亢一澜  贾有权 《实验力学》1992,7(4):387-390
本文介绍了两种新的光栅复制技术,它们具有快速、高质量、低成本、操作简单、使用方便、不需特殊仪器等特点.该技术从我国一般力学实验室条件出发,解决了试件栅制作困难,其中漆栅方法可极大地缩短云纹干涉方法的实验周期,该技术也为光栅测试技术的广泛应用提供了方便.  相似文献   
15.
以三氯化钌、2—2联吡啶为主要原料,甲基丙烯酸甲酯为基质,制备了钌联吡啶/聚甲基丙烯酸甲酯发光温敏漆,并对其温度猝灭特性进行了研究。扫描电镜观察发现钌联吡啶为规则的层状六边形结构;差热-热重测试表明钌联吡啶在320℃发生分解。紫外吸收光谱分析发现,温敏漆的适合激发光波长区间为410~500nm。荧光光谱测试结果表明温敏...  相似文献   
16.
密度比和吹风比对透平静叶气膜冷却的影响   总被引:3,自引:0,他引:3  
燃气轮机中冷却空气和高温燃气的密度比和吹风比是影响透平叶片气膜冷却性能重要因素。本文采用压力敏感漆技术,对燃气轮机第一级静叶栅气膜冷却的冷却性能进行了实验研究。实验中测量了静叶栅在不同密度比(1.5/1.0)和不同吹风比条件下的冷却效率。密度比的改变射流的出口动量,造成射流出口的流动特征发生变化,从而影响冷却效率,影响...  相似文献   
17.
Abstract: This article presents a review of the published articles related to the novel application of spectroscopy and microscopy methods in paint and coatings quality evaluation. Traditional and simple techniques have been used in paint and coating industry for many years and proven to be effective. However, the paint and coating industry faces new formulations with nontraditional applications. Therefore, the industry needs to adjust itself with the current sophisticated production and testing methods. There are a number of modern microscopy and spectroscopy techniques that can be utilized in the paint and coating industry for a better understanding of the product quality and/or application performance. This, in particular, is highly applicable in modern and nontraditional applications such as nanotechnology and smart coatings. Though importance of spectroscopy and microscopy methods is being increasingly recognized in the industry, there is no current comprehensive review available to highlight the need for novel application of these techniques in surface coatings evaluations.  相似文献   
18.
A novel methacrylate monomer bearing 5,10,15,20‐tetraphenylporphyrinato palladium(II) (PdTPP) (monomer 1a ) was synthesized and copolymerized with isobutyl methacrylate (IBM) and 2,2,2‐trifluoroethyl methacrylate (TFEM) to give poly (IBM‐co‐TFEM) bearing PdTPP (copolymer 2a ) as a dye‐conjugated oxygen‐permeable polymer for pressure‐sensitive paint applications. The introduction of PdTPP into copolymer 2a was confirmed by UV–vis spectroscopy and extended X‐ray absorption fine structure analysis. The Stern–Volmer plots of the copolymer 2a and a mixture of PdTPP and poly(IBM‐co‐TFEM) both showed downward curvature, unlike that of the platinum complex analogue (copolymer 2b ) previously reported. The plots were successfully fitted with a two‐site model to give two distinct Stern–Volmer constants (KSV1 and KSV2) and the partition ratio f1. Interestingly, the f1 values for the copolymer 2a were almost constant at about 0.98, whereas those of the mixture of PdTPP and poly(IBM‐co‐TFEM) increased from 0.889 to 0.967 as the temperature was increased. This finding suggests that there are two distinct microheterogeneities, one temperature‐dependent and the other temperature‐independent, in the mixture of PdTPP and poly(IBM‐co‐TFEM). The dye‐conjugation approach effectively eliminates the temperature‐dependent, but not the temperature‐independent microheterogeneity. The luminescence decays of copolymers 2a and 2b and the corresponding mixtures in the absence of oxygen indicated that the temperature‐dependent microheterogeneity involves an oxygen diffusion process, whereas the temperature‐independent one appears to be inherent nature in PdTPP. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 663–670, 2010  相似文献   
19.
Monitoring of Paint Drying Process by Digital Speckle Correlation   总被引:1,自引:0,他引:1  
The state of drying paint is monitored from the dynamic behaviors of the speckle pattern arising from laser illumination of the region inspected. Temporal variation of the peak height of the cross-correlation function between successive frames taken with a fixed interval is plotted until the peak maintains a stationary maximum value. We used a speckle pattern in the diffraction field for monitoring of a single region and that in the image field for simultaneous monitoring of various regions. Both the normal and the phase-only algorithms were compared for cross-correlation computation. The former showed more distinct variation of peak height.  相似文献   
20.
Modern oil paints, introduced at the beginning of the 20th century, differ from those classically used in antiquity in their chemical and compositional features. The main ingredients were still traditional drying oils, often used in mixtures with less expensive oils and added with several classes of additives. Consequently, detailed lipid profiling, together with the study of lipid degradation processes, is essential for the knowledge and the conservation of paint materials used in modern and contemporary art.  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