The vibrational mode structure of a golf ball

In this paper, we report the discrete frequencies at which golf balls can vibrate, the mode patterns of these vibrations and how these modes can be excited. There are two broad classes of modes: those that radiate sound waves and those that do not. Both silent and acoustic modes are excited by tangential (i.e. spin-producing) impact forces; only acoustic modes are excited by radial impact forces. Exact analytical results for a homogeneous ball core are compared with finite element numerical results for both a core and a model two-piece ball. Correspondences are readily established for the important low-frequency modes, and the good agreement suggests the validity of these results for real golf balls. The results potentially provide the basis for a rapid, simple and non-destructive method of measuring the effective high-frequency elastic shear modulae of balls (and ball cores) as well as a method for 'tuning' the performance of balls for specific clubs. Some of these aspects are explored further in our companion paper in this issue.     

Ensuring technical competency for management of research-focused organizations

Does a national research-focused organization need a technically competent leader? This study provides preliminary answers to that question using a natural experiment underway at the Department of Energy (DOE): a leader with significant high-level management experience superior to that of his predecessors, but no relevant technical experience was appointed to run the vast scientific research operation. The following hypothesis is proposed: A major risk of allowing technically-unqualified leadership is that an amateur can be more easily manipulated by special interests against the best interests of the nation. The hypothesis is tested by technically analyzing three case studies on proposals from the Secretary of Energy. The results show 1) requests for budget cuts undermining DOE's mission, 2) requests for redundant studies wasting DOE resources, and 3) counter-productive recommendations derived from a misrepresentation of the studies' results, which indicate technical competence is important for DOE leadership. These preliminary results indicate technical competency is important for leaders running organizations that oversee research. Finally, a potential policy safe guard to the risks of extreme technical incompetence is provided, which can be applied to either independent- or politically-appointed bureaucrats.     

现代教学环境设施建设与管理策略初探

在教育信息化、数字化新技术广泛深入高校课堂教学的今天,现代教学环境建设已成普及之势。本文结合我校现代教学环境建设过程中出现的一些问题,对教学环境设施如何更好地建设和管理策略提出了一些建设性的探究思路。     

泛在知识环境下的图书馆

介绍基于数字图书馆普及所产生的泛在知识环境的背景和特点,分析泛在知识环境下的新型知识发布和交流模型(知识链),认为图书馆需要重新定位,泛在知识环境下的图书馆应该成为“知识社区”。     

儒学的"天人合一"与人类生存环境保护

“天人合一”作为儒学传统的价值观念,其基本要求是保持人与自然的平衡与和谐.从现代化的历史需要出发,超越传统,重新审视、改造与利用这一观念,对于当今合理地开发与利用自然资源,保护和改善人类生存环境具有积极意义.     

我国女排在第28届奥运会排球赛上后排进攻技术运用现状的分析

主要采用录像统计法、文献资料法、比较分析法等，通过对我国女排在第28届奥运会排球赛上和第9届世界杯女排赛上后排进攻的运用现况进行统计分析，找到了中国女排后排进攻运用上存在的问题，为中国女排在今后的训练上提供参考和帮助。     

奥林匹克运动实践中的危机倾向

现代奥林匹克运动在取得巨大成就的同时，也面临许多难以解决的问题，潜伏着严重的危机，主要是：政治干扰，民族问题，由于职业选手参赛而引发的信仰危机和参赛条件的不平等，商业化与奥林匹克理想的矛盾，商业化加大地区间体育发展的差距及其对奥运会正常赛事的干预。     

The Greek elementary “What Is Happening In this Class?” (G-EWIHIC): A three-phase multi-sample mixed-methods study

Students’ perceptions of their classroom psycho-social climate (CPSC) have been found to relate significantly to students’ learning outcomes. The What Is Happening In this Class? (WIHIC) being one of most prominent instruments in measuring these perceptions. The purpose of the present study was to thoroughly examine the structure of preadolescents’ perceptions of the CPSC, through an elaborate mixed-methods three-phase design, in the Greek elementary school context. The study included semi-structured interviews with students and teachers, and two large-scale administrations of the qualitatively adapted WIHIC version. Both qualitative and quantitative results supported the seven-subscale structure of the instrument and identified potential issues with the conceptual content of two of the subscales. Quantitative findings also supported the theoretical second-order factorial structure of the instrument, but with different subscale allocation. The advantages of mixed-methodology in the cross-cultural examination of student’s perceptions of the learning environment and implications for research are discussed.     

历史时期长江流域农业生态变迁述论

历史时期长江流域气候、水土和森林植被等生态环境要素的变迁,与人类活动尤其是以稻空大点作生产为中心的农业活动有密切关系。一方面生态环境制约着稻作农业的发展变化,另一方面,农业活动对生态环境具有不同程度的影响。宋元以来,南方地区以围湖造田、丘陵山地开垦为主的大规模农业经济开发,对长江流域生态环境诸要素的负面作用逐步加大,导致水土流失、河湖淤塞和水旱灾害频发,农业生产和民众生活也因此受到很大危害。近现代长江流域经济开发进一步扩张,河湖淤废、森林破坏有增无减,而且水土环境的化学污染越来越严重。长江流域是中国稻作文明的发源地和主要的稻米产区,研究长江流域生态环境诸因素变迁与稻作农业发展的关系,对于保护区域生态环境,指导当地农业可持续发展,具有重要学术意义。     

加强大学生政治参与的思考

培养大学生理性政治参与意识,端正大学生政治参与动机,提高大学生政治参与能力,破解大学生政治参与难题,实现大学生的有序、理性的政治参与对于增强大学生的政治责任感、归属感,加快我国政治发展、推动社会全面进步具有重要的意义。