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71.
郑丹  田娟  张熙贵  夏保佳 《化学世界》2008,49(2):113-116,120
分析了研究和发展微型质子交换膜燃料电池(μPEMFC)的重要意义和应用前景,介绍了基于多孔硅及MEMS技术的μPEMFC最新研究动态,讨论了μPEMFC的结构设计、加工过程及性能,提出了μPEMFC仍存在的问题及其技术发展对策。  相似文献   
72.
Three new polymeric aromatic lithium sulfonylimides were used as salts in high molecular weight poly(ethylene oxide) (PEO) electrolytes. Their conductivity and electrochemical stability behaviors were investigated. The electrolytes with lithium poly[4,4′‐(hexafluoroisopropylidene)diphenoxy]sulfonylimide (LiPHFIPSI) showed a better conductive performance compared with the other two lithium salts. The best conductivity was obtained for PEO/LiPHFIPSI EO/Li = 16 (1.90 × 10?4 S/cm at 60°C). Thermal analysis indicated that the salts effectively decreased the crystallinity of PEO. Moreover, the electrolytes also had good electrochemical stability and their oxidative potential was to 5.5 V versus Li/Li+. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1802–1805, 2002  相似文献   
73.
74.
BACKGROUND: Defects in the skull have presented difficult reconstructive problems. Recently glass-ionomer cement and preformed. implants have been used to repair bony defects in the skull base and in cranio-facial surgery. Three patients are reported to illustrate possible applications for this new material. METHODS: Ionocap cement and Ionoroc-skull standardized implants have been used. The cement is available as a two component blister pack. When mixed and blended a gel is produced which can be worked for approximately 5 min before hardening. It can then be contoured and drilled to the required shape. The resultant material is biocompatible and biostable, is non-toxic and permanently bonds to bone with no increase in temperature or shrinkage. RESULTS: The material has been used to fill the temporal defect left by transplantation of the temporalis muscle for oral reconstruction, the anterior and lateral walls of the maxilla and following craniofacial resection, the posterior wall of the frontal sinus and anterior skull base. CONCLUSIONS: Three patients with different reconstructive problems have been presented to illustrate the use of an alloplastic material that has a tensile strength similar to bone and firmly adheres to it. The material was found to be safe and easy to use. All three patients have now been followed for 12 months with no adverse affects.  相似文献   
75.
In a complex social, political, economic, technological, and/or environmental context, corporate, military, government, and other organizations are often faced with collective decision-making situations. The rationale for group decision exercises is that the judgment of many will usually prove superior to the judgment of one. However, it has been shown that collective decision exercises are often highly dependent on matters of perspective, values and opinion, all of which - being essentially subjective in nature - are beyond the reach of existing formal decision technology. Furthermore, it can be expected that many collective decision exercises - particularly those of strategic import - will not lend themselves to the quantitative analysis instruments that have long dominated the management and decision science repertoire. This does not, however, mean that they must remain entirely and forever outside the bounds of scientific rationality. The ordering protocols which are currently available do not have enough technical mechanics to be relied upon to bring us to any satisfying resolution of a priori disputation. Hence, we propose an a priori ordering reference model that might support consensus-building in a multiple stakeholders context. In order to detect whether the subjective arguments are products of proper reasons or merely instances of raw rhetoric and to suggest how any logical or syntactical flaws might best be repaired, we propose logical ordering facilities and protocols for integrating procedural and instrumental provisions for a group-decision process with two lines of technical innovation: the superimpositional ordering function and the logical ordering support facilities.  相似文献   
76.
介绍了高温超导红外探测器电极材料的选择和制备。选用先蒸、后蒸金,再合金化的电极工艺。芯片装配成器件后,器件性能稳定,膜层牢固,接触电阻小。  相似文献   
77.
Quinine and quinidine are reported to potentiate the behavioural effects of serotonergic agents and monoamine uptake inhibitors. We have therefore investigated the presynaptic actions of quinine and quinidine on monoamine uptake and release in rat brain tissue in vitro. Quinidine evoked the release of [3H]5-HT, [3H]noradrenaline and [3H]dopamine from pre-loaded rat brain slices in a concentration dependent manner with EC50 values of 175, 486 and 150 microM, respectively. Quinine induced [3H]monoamine release with similar potencies. Both quinine and quinidine also inhibited the active uptake of [3H]5-HT, [3H]noradrenaline and [3H]dopamine into rat brain synaptosomes with IC50 values in the range 0.13-12.4 microM. The potency of each drug to inhibit [3H]5-HT uptake was significantly higher than that for [3H]noradrenaline or [3H]dopamine. The relative potency of quinidine compared to quinine was more marked in the case of [3H]5-HT (58-fold) than for [3H]noradrenaline (3-fold) or [3H]dopamine (4-fold). The inhibition of [3H]5-HT uptake by quinine and quinidine was competitive in nature and corresponded with the potencies of these drugs to inhibit [3H]paroxetine binding. No correlation was observed between the potencies of quinine and quinidine to induce the release of [3H]monoamines and to inhibit their uptake, suggesting that these effects are mediated by two distinct mechanisms. We conclude that the presynaptic actions of quinine and quinidine on monoamine uptake and release may be implicated in their potentiation of the effects of serotonergic agents and uptake blockers.  相似文献   
78.
本文介绍了ConcurrentC语言在一分布式系统上的实现。该实现使用了不同于预编译法的编译器的构造方法,同时将Concurrent C语言中的进程实现为UNIX进程中的用户级线索,是ConcurrentC语言在分布式系统上的一种高效实现。  相似文献   
79.
In this paper,we address the need for better hands-on learning materials in computing education and the need for integrating mobile computing education into computing curricular.We propose an innovative learning approach that uses state-of-the-art mobile computing technologies and devices to design a highly accessible and real-world relevant hands-on labware for computing education.The labware employs a modular design such that the learning materials can both be combined together into a single course of mobile program development and be integrated into the related computing courses as building blocks.The labware will help students understand the concepts,improve their problem solving skills,and prepare them for the mobile computing industrial workforce.The pilot modules of the labware have been presented to undergraduate students and have received positive feedbacks.  相似文献   
80.
文章介绍了波形数字化仪的原理、结构、工作方式及特点,并针对其校准技术进行了深入的研究。通过多功能校准源、示波器及测试系统数字模块实现波形数字化仪模块的精确校准,解决了波形数字化仪模块的校准问题。校准结果表明,该校准装置及校准方法能够满足集成电路测试系统任意波形发生器的校准要求。  相似文献   
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