通用竞争战略研究方法论的历史反思——一个基于博弈与约束优化建模的新研究架构

本文从独特的方法论视角回顾了通用竞争战略实证研究的历史,首次关注了其中的Palepu战略识别假设和战略数理解析的研究,分析了制约其发展的关键方法论问题;评述了近期战略解析建模研究的突破性进展及相关实证研究的进展的新方法论涵义,发现了反传统的理论建构性研究所面临的机遇,预测了通用战略建模、Palepu战略识别假设的解析验证和相关实证研究可能成为研究前沿。最后,提出了一个跨战略管理、财务管理和博弈论-约束优化三个领域的新研究架构设想。     

Resonance strategies for the belting style: Results of a single female subject study

This study explores resonance strategies used for the belting style and associated vocal fold vibratory patterns, for the vowels /e/, /a/, /i/, and /u/ on G4 and B4-flat. Acoustic spectra of belted vowels and their unoptimized, "speech-like" equivalents were compared. Vocal fold vibratory patterns were quantified using electroglottography. Results show that /a/ is inherently suitable for belting and requires no adjustment. For /e/, F2-H5 tuning was observed. For /i/, F1 was detuned from H1, enhancing also H2. For /u/, both F1 and F2 were raised to accomplish F2-H3 tuning. These results show that the loud, bright sound of the belting style is achieved by the implementation of resonance strategies that enhance higher harmonics. Electroglottography revealed that resonance strategies also result in raising the closed quotient (CQ) above 52%, an apparent threshold value for belting.     

A modified Newton direction for unconstrained optimization

In this article, a modification on Newton's direction for solving problems of unconstrained optimization is presented. As it is known, a major disadvantage of Newton's method is its slowness or non-convergence for the initial point not being close to optima's neighbourhood. The proposed method generally guarantees the decrement of the norm of the gradient or the value of the objective function at every iteration, contributing to the efficiency of Newton's method. The quadratic convergence of the proposed iterative scheme and the enlargement of the radius of convergence area are proved. The proposed algorithm has been implemented and tested on several well-known test functions.     

Making sense of shape: An analysis of children's written responses

In this study, we examine a large set of student responses to a constructed-response geometry item on the National Assessment of Educational Progress (NAEP) administered in 1992 and 1996. The item asks students to name the similarities and differences between a parallelogram and a rectangle of equal area presented side by side on a grid. Through categorization of student work utilizing the constant comparison method [Lincoln, Y. S., & Guba, E. G. (1985). Naturalistic Inquiry, Beverly Hills, CA: Sage Publications], we identified two distinct categories of responses. The first group of responses indicates that students view the two figures as the same based on flexible prototypes while the second group indicates students view the two figures as distinct shapes based on inflexible prototypes. The research uncovers responses that show evidence of students’ development of a dynamic figural concept in which student understanding is based on sense-making that involves mentally manipulating the shapes. In addition, the research highlights the richness of the evidence obtained from constructed-response items administered as part of standardized assessments.     

把握物理化学研究前沿,完善科学基金重点项目领域立项与管理工作

通过分析日本学术振兴会调研中有关物理化学的光谱学、界面化学和理论化学研究的发展趋势, 总结我国大陆地区科学基金资助的部分重点项目研究领域及其研究进展, 旨在提出今后国家自然科学基金物理化学重点研究领域资助的策略及思考.     

基于便利收益的商品期货套期保值策略研究

依据便利收益是商品现货与期货长期均衡关系的主要影响因素,研究商品便利收益对商品期货套期保值策略的影响。通过求解最大化期望效用的套期保值决策模型,得到了最优套期保值比率的封闭解,并且提出了以便利收益为修正因子的ECT-GARCH模型,同时选取2005年01月到2013年10月期间沪铝现货和期货数据进行实证分析。研究发现:便利收益的波动性与套期保值比率呈负相关,在套期保值比率估计精度和套期保值绩效方面,ECT-GARCH模型均优于B-GARCH模型和ECM-GARCH模型。     

第十一届全国周培源大学生力学竞赛"理论设计与操作"团体赛冠军队设计方案

本文主要介绍了清华大学代表队在第十一届全国周培源大学生力学竞赛"理论设计与操作"团体赛中的解题思路、操作过程和设计方案,简要总结了此次参赛的经验和教训。     

Innovative determination of polar organophosphonate pesticides based on high‐resolution Orbitrap mass spectrometry

The determination of compounds showing a very low molecular weight (i.e. < 200 Da) can be complicated when low‐resolution mass spectrometry is used in the selected‐reaction monitoring mode, since the possible number of product ions is reduced and the obtained reactions are not selective enough to overcome background noise and/or matrix interferences. In this study, the use of high‐resolution mass spectrometry based on Exactive Orbitrap was applied for the determination of a group of polar organophosphonate pesticides and transformation products (TPs), which show the aforementioned features, in agricultural soils. Namely, glyphosate, glufosinate, ethephon and their TPs, aminomethyl phosphonic acid (AMPA), 3‐methylphosphinicopropionic acid, N‐acetyl‐glufosinate and 2‐hydroxyethylphosphonic acid were analyzed. The [M‐H]^‐ ions 168.00564, 180.04202, 142.96593, 110.00016, 151.01547, 222.05259 and 124.99982 were used, respectively, for the detection and identification of the compounds. Confirmation was carried out by using accurate mass measurements of ion fragments for each compound, from neutral losses of CO₂, H₂O and H₂CO (formaldehyde). Furthermore, the recently reported tool, relative isotopic mass defect (RΔm), was also used to support the confirmation protocol. The optimized method was fully validated at low levels, including the estimation of a not commonly used parameter: the limit of confirmation (LOC). This LOC is expressed as the lowest concentration of compound that can be confirmed using a fragment or the RΔm, and it ranged from 10 to 50 µg kg^?1 for all compounds. All the data was obtained in a single injection. Finally, the method was applied to real soil samples, and glyphosate and AMPA were found at 265 µg kg^?1 and 105 µg kg^?1, respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

基于因子分析的元认知外语教学策略研究

从心理学、第二语言习得理论出发,研究了场独立与场依存认知风格的外语学习者特点,应用因子分析数学模型,进行了培养元认知策略意识及发展双重认知风格等教学策略的教学实验,仿真实验表明了该方法的实用性和有效性.