扫描探针显微镜在机械教学中的应用

介绍扫描探针显微镜教学演示软件。该软件将CAI技术和SPM技术结合在一起，主要运用文字说明，静态图像，三维动画，模拟仿真等方法，对SPM的初学者进行了SPM的原理介绍和使用培训，可以大大缩短他们的学习时间，并能使其在较短的时间内对SPM有个较为深入和全面的了解。     

掏空效应还是支持效应?大股东影响公司战略的经济效果——基于中国医药制造企业前向一体化和多元化选择的实证分析

本文以中国医药制造上市公司九年数据为样本,实证分析了股权结构影响公司战略选择的经济效果。结果表明:在医药制造公司中,实施前向一体化战略对公司绩效没有显著的正面或负面影响,而实施多元化战略对公司绩效存在显著的负面影响,这说明在公司选择扩张投资时,前向一体化战略与多元化战略相比更为理性;同时,股权集中度提高会促进公司实施前向一体化战略,但会制约公司实施多元化战略,这说明当存在大股东且股权集中时,大股东会监督经理使其实施对公司来说更理性的战略。本文的结论是,大股东在影响公司战略选择时,支持效应会大于掏空效应。     

The Million Book Project at Bibliotheca Alexandrina

INTRODUCTION The Bibliotheca Alexandrina (BA) has develop- ed a workflow for turning printed books into digital books. The process starts with selection of books to be digitized, which is done mainly by BA’s Library Service Department. Books metadata is entered into the Digital Lab database. Metadata entry is followed by three core phases: scanning phase, in which the digital copy is generated; processing phase, in which image enhancement is performed; and OCR phase, in which text i…     

Surface settlement caused by twin-parallel shield tunnelling in sandy cobble strata

City metro tunnels are usually constructed as twin-parallel tunnels and their adjacent construction may lead to surface deformation, affecting the surface environment and the safety of the tunnels. Due to its strong dispersion, sandy cobble strata can be easily disturbed by shield tunneling. Based on the project of the Chengdu Metro Line 1, field and model tests were carried out to study the surface settlement caused by shield tunneling in sandy cobble strata by measuring surface settlement curves, ground loss ratios and construction influence zones. The discrete element method (DEM) was used to study the factors affecting the formation of ground arches in sandy cobble strata at the microscopic level. Results show that the shape of the surface settlement curve in sandy cobble strata is different from that in soft soil. The buried depth and clear spacing of the two tunnels had a significant impact on the formation of ground arches.     

Integration of virtual microscopy podcasts in the histology discipline in osteopathic medical school: Learning outcomes

Virtual microscopy podcasts (VMPs) are narrative recordings of digital histology images. This study evaluated the outcomes of integrating the VMPs into teaching histology to osteopathic medical students. The hypothesis was that incorporating virtual microscopy podcasts as supplementary histology resources to the curriculum would have a positive impact on student performance and satisfaction. Sixty-one podcasts of dynamic microscopic images were created using screen recordings of the digital slides. The VMPs were integrated as supplementary histology resources in multiple courses during the first and second years of the medical curriculum for three classes, a total of 477 osteopathic medical students. A voluntary and anonymous survey was obtained from the students using a questionnaire that included two open-ended questions. The overall performance of the three classes on the histology content of the preclinical course examinations was compared to historical controls of the previous two classes that did not have access to the VMPs. Most students indicated that the podcasts enabled more efficient study time and improved their confidence in the histology content on examinations. The findings indicated a positive association between podcast viewing and efficient study time utilization and class performance. The class average scores of the three consecutive cohorts that used the VMPs progressively increased by 7.69%, 14.88%, and 14.91% compared to the controls. A summary of students' feedback and academic performance supported that integration of the VMPs into Histology teaching improved the learning experience. The findings align with previous studies on the effectiveness of multimedia-based teaching in histology laboratory modules.     

Evaluation of virtual microscopy in medical histology teaching

Histology stands as a major discipline in the life science curricula, and the practice of teaching it is based on theoretical didactic strategies along with practical training. Traditionally, students achieve practical competence in this subject by learning optical microscopy. Today, students can use newer information and communication technologies in the study of digital microscopic images. A virtual microscopy program was recently introduced at Ghent University. Since little empirical evidence is available concerning the impact of virtual microscopy (VM) versus optical microscopy (OM) on the acquisition of histology knowledge, this study was set up in the Faculty of Medicine and Health Sciences. A pretest‐post test and cross‐over design was adopted. In the first phase, the experiment yielded two groups in a total population of 199 students, Group 1 performing the practical sessions with OM versus Group 2 performing the same sessions with VM. In the second phase, the research subjects switched conditions. The prior knowledge level of all research subjects was assessed with a pretest. Knowledge acquisition was measured with a post test after each phase (T1 and T2). Analysis of covariance was carried out to study the differential gain in knowledge at T1 and T2, considering the possible differences in prior knowledge at the start of the study. The results pointed to non‐significant differences at T1 and at T2. This supports the assumption that the acquisition of the histology knowledge is independent of the microscopy representation mode (VM versus OM) of the learning material. The conclusion that VM is equivalent to OM offers new directions in view of ongoing innovations in medical education technology. Anat Sci Educ 6: 307–315. © 2013 American Association of Anatomists.     

HistoViewer: An interactive e‐learning platform facilitating group and peer group learning

Understanding tissue architecture and the morphological characteristics of cells is a central prerequisite to comprehending the basis of physiological tissue function in healthy individuals and relating this to disease states. Traditionally, medical curricula include courses where students examine glass slides of cytological or tissue samples under a light microscope. However, it is challenging to implement group and peer group learning in these courses and to give students sufficient time to study specimens. An increasing number of medical schools have thus started to implement digital slide viewers, so‐called virtual microscopes, in histology and histopathology. These websites are mostly based on standard commercial software and offer limited adaptation to the special needs of first‐year students. An e‐learning platform has therefore been developed for use in cytology and histology courses. This virtual microscopy tool is coupled to a central database in which students can label and store the positions of individual structures for later repetition. As learning in pairs and peer groups has been shown to provide a high learning outcome, identified structures can be shared and discussed with students' peers or faculty via a built‐in communication module. This website has the possibility of opening an arbitrary number of frames which all can actively be moved and changed in magnification to enable the comparison of specimens and thus encourage a more global understanding of related tissues. HistoViewer is thus suggested as an e‐learning tool combining several modern teaching concepts. © 2013 American Association of Anatomists.     

Development and evaluation of an interactive electronic laboratory manual for cooperative learning of medical histology

This article describes the development of an interactive computer‐based laboratory manual, created to facilitate the teaching and learning of medical histology. The overarching goal of developing the manual is to facilitate self‐directed group interactivities that actively engage students during laboratory sessions. The design of the manual includes guided instruction for students to navigate virtual slides, exercises for students to monitor learning, and cases to provide clinical relevance. At the end of the laboratory activities, student groups can generate a laboratory report that may be used to provide formative feedback. The instructional value of the manual was evaluated by a questionnaire containing both closed‐ended and open‐ended items. Closed‐ended items using a five‐point Likert‐scale assessed the format and navigation, instructional contents, group process, and learning process. Open‐ended items assessed student's perception on the effectiveness of the manual in facilitating their learning. After implementation for two consecutive years, student evaluation of the manual was highly positive and indicated that it facilitated their learning by reinforcing and clarifying classroom sessions, improved their understanding, facilitated active and cooperative learning, and supported self‐monitoring of their learning. Anat Sci Educ 6: 342–350. © 2013 American Association of Anatomists.     

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

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.     

铁磁－非磁性杂质－铁磁隧道结磁电阻效应

基于波函数匹配方法,研究了铁磁-非磁性杂质-铁磁系统的隧道结磁电阻,结果表明,在一定条件下两铁磁结之间分子场的存在导致了准束缚态的形成。当电子入射能量接近准束缚态能级时共振隧穿发生,在其电导中出现一个峰值。非磁性杂质和两铁磁体中的电子有效质量对微分电导有明显的影响,包括影响电导的幅度和共振峰的位置。