《借贷关系与乡村变动——民国时期华北乡村借贷之研究》简评

近年来,区域社会经济史的研究已成为一股强劲的中外学术潮流,李金铮新著<借贷关系与乡村变动--民国时期华北乡村借贷之研究>(河北大学出版社2000年出版),就是其中一部填补学术空白之作.

福建女性社会地位的变迁:1990-2000

本文利用第二期中国妇女社会地位抽样调查资料,通过与第一期抽查结果的动态比较以及与全国平均水平的横向对比,描述福建省女性社会地位的积极变化,分析福建女性社会地位发展中还存在的问题,并提出进一步提高福建女性社会地位的主要对策。

试论客观性原则

试论客观性原则ＯｎｔｈｅＯｂｊｅｃｔｉｖｉｔｙＰｒｉｎｃｉｐｌｅ□文／肖斌代敏会计人员从事会计工作，必须遵循一定的规范或规则，我们称之为会计基本原则。客观性原则作为评价会计信息质量特征的重要要求，归之为会计基本原则之一。何为客观性原则？我们一般认为：...

Variation Dynamics of Total Nitrogen and Nicotine of Burley Tobacco at Various Growing Stages under Different Nitrogen Nutrition Levels

[Objective] This study aimed to investigate the variation dynamics of total nitrogen and nicotine of burtey tobacco at various growing stages under different ni- trogen nutrition levels to provide reference for optimizing fertilization technologies for burley tobacco. [Method] Fresh burley tobacco leaves were collected at various growing stages and dried to measure the content of total nitrogen, protein and nico- tine by using INTEGRAL automated chemical analyzer and analyze the correlation with nitrogen application level. [Result] Regardless of the nitrogen application level, the content of total nitrogen and protein showed a downward trend since root ex- tending stage and reached the minimum at mature stage; the content of nicotine showed an upward trend since early vigorous growing stage and increased to the maximum at mature stage; the content of total nitrogen, protein and nicotine all in- creased after air curing; the content of total nitrogen, protein and nicotine showed positive correlation with nitrogen application level, while total nitrogen/nicotine was negatively correlated. The results indicate that nitrogen level is closely related to the total nitrogen and nicotine of burley tobacco at growing period and post-air curing, rational application of nitrogen is an important measure to regulate the content of total nitrogen and nicotine of tobacco. [Conclusion] This study provides scientific ba- sis for rational fertilization of burley tobacco.

Volatility forecasting in Chinese nonferrous metals futures market

This paper seeks to model and forecast the Chinese nonferrous metals futures market volatility and allows new insights into the time-varying volatility of realized volatility and leverage effects using high-frequency data.The LHAR-CJ model is extended and the empirical research on copper and aluminum futures in Shanghai Futures Exchange suggests the dynamic dependencies and time-varying volatility of realized volatility,which are captured by long memory HAR-GARCH model.Besides,the findings also show the significant weekly leverage effects in Chinese nonferrous metals futures market volatility.Finally,in-sample and out-of-sample forecasts are investigated,and the results show that the LHAR-CJ-G model,considering time-varyingvolatility of realized volatility and leverage effects,effectively improves the explanatory power as well as out-of sample predictive performance.

Analysis of the Mode of the Periodically Time-varying Vibration Systems

By Liapunov reducibility theorem, the periodically time-varying vibration system can be transformed to a linear time-invariant system. Based on the dynamic characteristics of the linear time-invariant system, the mode of the periodically time-varying vibration system has been discussed. The paper defines the mode and analyzes its characteristics. It can be found that the mode of the periodically time-varying system is periodically time-varing but has such characteristics as orthogonality. Finally, a method is given to solve the mode. By solving the eigenvalues and the eigenvectors of the state transition matrix in one period, the periodically time-varying mode can be obtained.

Regional Innovation Policies for High-Technology Firms： The Importance of the Cluster Life Cycle

The present work makes an in-depth analysis of an aspect not yet sufficiently examined by the studies into regional innovation systems, relating to why the policy makers must adopt regional innovation policies in accordance with the development cycle of the active clusters in the territory. The analysis carried out in the course of the work contributes towards understanding the validity of an evolutionary-type development model for which the regional innovation policies for the growth of high-tech firms should dynamically change in relation to the various cluster stages. The development model proposed provides a framework for the policy makers in order to state more efficiently through time the regional innovation strategies.

Quantum Transport through a Rigidly Connected Double Quantum-Dot Shuttle

We design a double quantum-dot （QD） shuttle （DQDS） model including two rigidly connected QDs that are softly linked to two leads via deformable organic materiaJs. Based on the full quantum mechanical approaches we explore the influences on the electron transport induced by the electrical and mechanical degrees of freedom. First of a/l the modified rate equations of the DQDS are derived theoretically and then a numerical investigation on the quantum transport through the DQDS is performed. For the classical DQDS, the time-dependent evolutions of the electron- occupation probabilities and the currents flowing through the DQDS show the periodic oscillations with their periods determined by the oscillation period of the DQDS. Both the mechanical oscillation amplitude and the interdot coupling can play crucial roles in adjusting the peak shapes of the currents and the probabilities. For the quantum DQDS, the current and electron-occupation probabilities of the DQDS evolve into a stationary state as time goes on, with no periodical oscillations observed. As a consequence, the sharp differences of the time-dependent properties between the c/assica/ and quantum DQDS systems are clearly demonstrated, which should be greatly helpful in designing new nanoelectromechanical devices. Also, this work is of great significance to understanding the kind of rigidly connected QD shuttle systems that have more than two QDs.