中间与两极汇率制度演变趋势分析——基于两种分类方法的统计分析

"中空论"是近年来比较流行的汇率制度选择理论之一,文章分别采用Bubula and tker-Robe事实分类法和IMF官方事实分类法对147个样本国家1990-2001年和1999-2006年的汇率制度发展趋势进行统计分析,以期发现在现实中各国汇率制度选择是否存在"中空"的趋势。研究发现就147个国家的总体样本而言,中间汇率制度确有下降的趋势,但是相对比例仍然很高,"中空"的趋势并不明显,而不同类型的国家汇率制度演变趋势不同。

汇率制度选择理论的回顾与展望

汇率制度选择一直是国际金融领域备受关注的一个问题。文章对汇率制度选择的研究方法及视角进行了总结,并对传统的汇率制度选择理论和汇率制度的新进展进行了论述,进而对未来汇率制度选择的研究进行了展望。认为:由于存在"恐浮",应该依据实际实行的汇率制度而不是官方宣布的汇率制度进行研究;从动态角度进行汇率制度转换的研究也是很重要的发展方向;应该对中间与两极汇率制度进行统一的界定,建立支持或反对"中空论"的严格理论框架。

Assessing the range of blasting-induced cracks in the surrounding rock of deeply buried tunnels based on the unified strength theory

Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.

Advance in the research of sterilants against rodents

The advances in the application of sterilizing techniques against pest rodents in China are introduced in the paper. The development of chemosterilants, improvements of botanic sterilants, production of new steroid hormone sterilants, introduction of immunosterility and excellent properties of the sterilants are outlined. The 揝pace Occupation Theory?of sterile techniques is advanced after practice. The botanic sterilants with gossypol and trichosanthin as its main agents were screened and successfully applied in the large area control in the northern forest area of China. The safety of sterilants to non-target animals such as rats, rabbits, dogs, monkeys and chickens was summarized.

How to Determine the Upgrading Opportunities for Industries： Theory, Method and Policy

Industrial upgrading and transformation is important for China to transform its way of development. To accomplish this task effectively, we need to identify industries with potential comparative advantage. Using the latest data on international trade of products, this paper verifies the premise of heterogeneity of product space of the evolutionary theory of comparative advantage, and analyses the evolution of product space of China and most countries in the world. The paper makes predictions on China ＂s industries with potential comparative advantage in near terms using the product space theory, and carries out thorough discussion on the evolutionary track of industries under different proximity thresholds. The basic conclusion is that even as China＇s number of industries with comparative advantage is larger than the global average, its industrial upgrading capacity is limited, as it has fewer industries with potential comparative advantage and lower sustainability in the current sectors than the world average. China faces a dilemma in the process of industrial upgrading, as a rapid upgrading would cause a shock to current economic growth, and a slow one would not maintain sustainable growth. With limited industrial upgrading capacity, the best structure adjustment and upgrading strategy is to give full play to the advantage of China＇s industrial diversification and combination to achieve an inclusive upgrading.

Approximate Controllability of Neutral Functional Differential Systems with State-Dependent Delay

This paper deals with the approximate controllability of semilinear neutral functional differential systems with state-dependent delay. The fractional power theory and α-norm are used to discuss the problem so that the obtained results can apply to the systems involving derivatives of spatial variables. By methods of functional analysis and semigroup theory, sufficient conditions of approximate controllability are formulated and proved. Finally, an example is provided to illustrate the applications of the obtained results.