利用STM研究苝四羧酸分子间的作用机制     

刘春华  李亿保  谢云志  李勋  范小林 《赣南师范学院学报》2013,(6):32-35

通过对苝-3,4,9,10-四羧酸二酐(PTCDA)酸化,合成了苝-3,4,9,10-四羧酸(PTCA),采用红外、氢谱等方法对目标产物进行了表征.并且采用荧光光谱研究了产物的光学性质,结果表明:酸化后的PTCA表现出很强的荧光特性.为了进一步揭示分子作用机制,以高定向热解石墨HOPG(Highly Oriented Pyrolytic Graphite)为基底,利用扫描隧道显微镜(STM)研究了PTCA分子在固-液界面的二维(2D)自组装行为,实验结果表明了分子间的作用力来源于分子间的氢键和π-π堆积相互作用力.  相似文献   

Mapping intrinsic electromechanical responses at the nanoscale via sequential excitation scanning probe microscopy empowered by deep data     

Boyuan Huang  Ehsan Nasr Esfahani  Jiangyu Li 《国家科学评论(英文版)》2019,6(1):55

Ever-increasing hardware capabilities and computation powers have enabled acquisition and analysis of big scientific data at the nanoscale routine, though much of the data acquired often turn out to be redundant, noisy and/or irrelevant to the problems of interest, and it remains nontrivial to draw clear mechanistic insights from pure data analytics. In this work, we use scanning probe microscopy (SPM) as an example to demonstrate deep data methodology for nanosciences, transitioning from brute-force analytics such as data mining, correlation analysis and unsupervised classification to informed and/or targeted causative data analytics built on sound physical understanding. Three key ingredients of such deep data analytics are presented. A sequential excitation scanning probe microscopy (SE-SPM) technique is first developed to acquire high-quality, efficient and physically relevant data, which can be easily implemented on any standard atomic force microscope (AFM). Brute-force physical analysis is then carried out using a simple harmonic oscillator (SHO) model, enabling us to derive intrinsic electromechanical coupling of interest. Finally, principal component analysis (PCA) is carried out, which not only speeds up the analysis by four orders of magnitude, but also allows a clear physical interpretation of its modes in combination with SHO analysis. A rough piezoelectric material has been probed using such a strategy, enabling us to map its intrinsic electromechanical properties at the nanoscale with high fidelity, where conventional methods fail. The SE in combination with deep data methodology can be easily adapted for other SPM techniques to probe a wide range of functional phenomena at the nanoscale.  相似文献   

The virtual microscopy database—sharing digital microscope images for research and education          下载免费PDF全文

Lisa M. J. Lee  Haviva M. Goldman  Michael Hortsch 《Anatomical sciences education》2018,11(5):510-515

Over the last 20 years, virtual microscopy has become the predominant modus of teaching the structural organization of cells, tissues, and organs, replacing the use of optical microscopes and glass slides in a traditional histology or pathology laboratory setting. Although virtual microscopy image files can easily be duplicated, creating them requires not only quality histological glass slides but also an expensive whole slide microscopic scanner and massive data storage devices. These resources are not available to all educators and researchers, especially at new institutions in developing countries. This leaves many schools without access to virtual microscopy resources. The Virtual Microscopy Database (VMD) is a new resource established to address this problem. It is a virtual image file‐sharing website that allows researchers and educators easy access to a large repository of virtual histology and pathology image files. With the support from the American Association of Anatomists (Bethesda, MD) and MBF Bioscience Inc. (Williston, VT), registration and use of the VMD are currently free of charge. However, the VMD site is restricted to faculty and staff of research and educational institutions. Virtual Microscopy Database users can upload their own collection of virtual slide files, as well as view and download image files for their own non‐profit educational and research purposes that have been deposited by other VMD clients. Anat Sci Educ 11: 510–515. © 2018 American Association of Anatomists.  相似文献   

自组装单分子膜合成及其表征的研究进展     

周延辉 《广东轻工职业技术学院学报》2006,5(4):11-15

自组装分子膜的制备和表征是目前自组装研究领域的主要方向，此文总结了现阶段分子自组装膜的主要制备方法，并从扫描探针显微镜（SPM）、电化学、光谱学和接触角等方面综述了近几年来自组装单分子膜的表征方法的研究进展，概述自组装分子技术的现状及发展趋势。  相似文献   

数码显微互动教学促进新一轮生物学实验的创新     

林和  陈寅山  王娟 《实验技术与管理》2007,24(11):134-136

文章介绍生命科学院数码显微互动实验室的建设，探讨了数码显微互动技术进行生物学科基础教学实验的应用，有力地提高了实验教学效率与质量，激发了学生学习实验操作技能的积极性，学习效果显著提高，  相似文献   

荧光波长对双光子荧光共焦成像分辨率的影响     

白建平  赵文丽  肖华层 《南阳师范学院学报》2004,3(6):24-26

导出了共焦双光子荧光显微镜探测光强随荧光波长变化的解析表达式。研究了不同荧光波长对双光子荧光共焦显微镜横向、纵向分辨率和光斑强度的影响。结果指出，随着荧光波长与入射波长的比值的增加，横向和纵向分辨率降低，双光子荧光成像的分辨率高于单光子荧光成像的分辨率。  相似文献   

激光扫瞄共聚焦显微技术实验教学的思考   总被引：1，自引：1，他引：1  

刘继红  汪成楚 《实验技术与管理》2006,23(1):86-87

开设激光共聚焦技术实验课，通过仪器演示和实验操作，帮助学生理解课堂的理论教学内容，了解和掌握这门新技术，为他们在未来科研工作中利用该技术进行科学研究奠定基础。  相似文献   

Distribution characteristics of minerals and elements in chromite ore processing residue     

李国成  肖凯 《天津大学学报(英文版)》2012,18(1):52-56

In this paper,environmental scanning electron microscopy (ESEM) is applied to characterizing the mineral and element distribution of chromite ore processing residue (COPR).The test results show that Cr-bearing brownmillerite occurs in the rim of COPR particle,while hydroandradite with Cr(Ⅵ) in its structure presents inside the COPR particle.Periclase and calcite occur in the interstitial area.Element analyses show that Ca,Fe and Al are distributed throughout the COPR particle,and Mg exists mostly in the interstitial area or on the particle surface.A lower content of Cr is evenly distributed in the COPR particle,while slightly higher concentration of Cr occurs inside the particle.It is suggested that it will take a relatively longer time for Cr to migrate out of COPR,especially for hexavalent chromium,so the leaching time and the particle size may be two important factors to affect the release of Cr(Ⅵ).  相似文献   

亚波长金属扫描探针的场型结构及其透射特性     

曾夏辉 《闽江学院学报》2012,33(2):44-48

利用时谐电磁场理论和时域有限差分数值方法分析了亚波长金属扫描探针电磁场模式的场型结构和空间分布及透射特性等主要的传输性质,导出了亚波长金属探针内球横电模和球横磁模各电磁场分量的解析表达,运用数值求解获得的精确本征值,得到了金属探针内几个低阶模在球横截面内的场型结构．时域有限差分数值模拟研究结果表明,时谐电磁场的空间分布在亚波长金属探针内呈现准周期性振荡变化,并且在传输径向坐标上会出现一个最大值,最大值的位置随光波波长发生改变,研究结果还表明,在亚波长探针内刻蚀可以更好地激发和引导表面等离子体激元波到达出射孔径端口,提高亚波长空心锥的透射率和增强光学仪器的空间分辨率．  相似文献   

More technology,better learning resources,better learning? Lessons from adopting virtual microscopy in undergraduate medical education     

Laura Helle  Markus Nivala  Pauliina Kronqvist 《Anatomical sciences education》2013,6(2):73-80

The adoption of virtual microscopy at the University of Turku, Finland, created a unique real‐world laboratory for exploring ways of reforming the learning environment. The purpose of this study was to evaluate the students' reactions and the impact of a set of measures designed to boost an experimental group's understanding of abnormal histology through an emphasis on knowledge of normal cells and tissues. The set of measures included (1) digital resources to review normal structures and an entrance examination for enforcement, (2) digital course slides highlighting normal and abnormal tissues, and (3) self‐diagnostic quizzes. The performance of historical controls was used as a baseline, as previous students had never been exposed to the above‐mentioned measures. The students' understanding of normal histology was assessed in the beginning of the module to determine the impact of the first set of measures, whereas that of abnormal histology was assessed at the end of the module to determine the impact of the whole set of measures. The students' reactions to the instructional measures were assessed by course evaluation data. Additionally, four students were interviewed. Results confirmed that the experimental group significantly outperformed the historical controls in understanding normal histology. The students held favorable opinions on the idea of emphasizing normal structures. However, with regards to abnormal histology, the historical controls outperformed the experimental group. In conclusion, allowing students access to high‐quality digitized materials and boosting prerequisite skills are clearly not sufficient to boost final competence. Instead, the solution may lie in making students externally accountable for their learning throughout their training. Anat Sci Educ 6: 73–80. © 2012 American Association of Anatomists.  相似文献