Recent developments in intelligent biomedical polymers

Intelligent polymers or stimuli-responsive polymers may exhibit distinct transitions in physical-chemical properties, including conformation, polarity, phase structure and chemical composition in response to changes in environmental stimuli. Due to their unique 'intelligent' characteristics, stimuli-sensitive polymers have found a wide variety of applications in biomedical and nanotechnological fields. This review focuses on the recent developments in biomedical application of intelligent polymer systems, such as intelligent hydrogel systems, intelligent drug delivery systems and intelligent molecular recognition systems. Also, the possible future directions for the application of these intelligent polymer systems in the biomedical field are presented.

分散式控制和管理的UUV体系结构模型研究

针对传统的分层式体系结构在UUV 控制系统开发设计、维护和升级过程中所遇到的困难，首先分析了集中式控制和管理方法的不足和原因。在此基础上，借鉴自主计算的思想，提出了分散控制和管理的体系结构。这种方法把系统中每个独立的功能模块都抽象成为具有相同模型的控制基元，称之为“自主基元”，然后通过自主基元层次式、嵌套式的组织，构成完整的系统。分析表明，这种方法能够缩短控制系统的开发周期，也降低了维护和升级的难度。

AUV水下对接关键技术研究

对国内外主要AUV水下对接系统进行了研究,从对接方式、对接传感器、控制策略、流体干扰和对接失误对策五个方面阐述了AUV水下对接系统的方法、技术现状以及发展趋势.

A comprehensive comparison of fuel options for fuel cell vehicles in China

Fuel cell vehicles (FCVs) offer the potential of ultra-low emissions combined with high efficiency. Proton exchange membrane (PEM) fuel cells being developed for vehicles require hydrogen as a fuel. Due to the various pathways of hydrogen generation, both onboard and off-board, the question about which fuel option is the most competitive for fuel cell vehicles is of great current interest. In this paper, a life-cycle assessment (LCA) model was made to conduct a comprehensive study of the energy, environmental, and economic (3E) impacts of FCVs from well to wheel (WTW). In view of the special energy structure of China and the timeframe, 10 vehicle/fuel systems are chosen as the study projects. The results show that methanol is the most suitable fuel to serve as the ideal hydrogen source for fuel cell vehicles in the timeframe and geographic regions of this study. On the other hand, gasoline and pure hydrogen can also play a role in short-term and regional applications, especially for local demonstrations of FCV fleets. (c) 2004 Elsevier B.V All rights reserved.