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991.
本文提出了一个由液体密度和正常沸点下蒸发焓数据推算物质临界参数的新方法。本方法所需数据为:液体密度、ZRA值及正常沸点下蒸发焓。采用本文方法对有代表性的近100种有机物和16种无机物的Pc和Tc值进行了估算,结果表明本文方法稳定、可靠。 相似文献
992.
Novel self-curable cathodically depositable coatings were developed from glycidyl functional epoxy ester-acrylic graft co-polymer (EEAG) without using any external crosslinking agents. The EEAG-amine adducts (EEAGAs) were prepared by reacting EEAG with varying amount of diethanolamine (DEoA) which are neutralized with acid and dispersed in deionised water to give stable dispersion for cathodic electrodeposition (CED) coatings. The dispersions were cathodically electrodeposited on phosphated steel panels and thermally cured to give uniform coating. The coatings were evaluated for different mechanical, chemical and corrosion resistance properties. The coatings were evaluated for their thermal properties using thermo gravimetric analysis (TGA). The final properties of the coatings were found to be affected by the amount of amine reacted with epoxy. The coating films showed good overall performance properties for their use in coating industry. 相似文献
993.
研究了增容剂苯乙烯-丁二烯二嵌段共聚物,苯乙烯-乙烯/丙烯二嵌段共聚物和苯乙烯-乙烯/丁烯-苯乙烯三嵌段共聚物对LDPE/PS共混物分散相粒径尺寸的影响,结果表明,在增容剂用量约3%时,分散相的粒径尺寸接近最小值,进一步增加增容剂的用量,粒径尺寸没明显的变化;增容剂中苯乙烯嵌段和橡胶嵌段之间的溶度参数差越大,分子间排斥作用越大,分散相的粒径越小。 相似文献
994.
Cognitive radios such as intelligent phones and Bluetooth devices have been considered essential goods in next-generation communication systems.Such devices will have to share the same frequency band owing to the limited bandwidth resource.To improve spectrum efciency,we formulate multi-channel power allocation as a market competitive equilibrium(CE)problem,and prove that its solution exists and is unique under the condition of weak interference.We then propose two distributed power allocation algorithms achieving CE,namely the fast convergent power allocation algorithm(FCPAA)and the social-fairness-aware FCPAA(SFAF).Theoretical analysis and simulation results demonstrate that the proposed algorithms lead to better system performance in terms of the guaranteed interference temperature constraint using the price mechanism instead of a strategy based on the Nash equilibrium.Moreover,it is shown that the FCPAA maximizes total utility,and converges more quickly than the method addressed in prior research with the help of improved round-robin rules.However,the FCPAA cannot ensure the same social fairness among secondary users as the SFAF scheme in both the non-fading channel and Rayleigh fading channel;the SFAF balances the individual utility by adjusting each user’s budget at the expense of a small quantity of system total throughput. 相似文献
995.
The survivability is usually critical for wireless sensor networks,which are often deployed in the unattended harsh environment.Lots of technical schemes to improve the survivability depend on the redundant resources of the sensor networks.The amount of resources is usually determined by the node density during the deployment phase.For the random deployment and random node failures,the quantitative relation between the survivability and the node density is studied.Based on the conditional survivability,the node density to meet the required survivability level is presented.Finally,the survivability for unpredictable failures and the optimal node density to maximize the price–performance ratio are also discussed. 相似文献
996.
Software systems can be represented as complex networks and their artificial nature can be investigated with approaches developed in network analysis.Influence maximization has been successfully applied on software networks to identify the important nodes that have the maximum influence on the other parts.However,research is open to study the effects of network fabric on the influence behavior of the highly influential nodes.In this paper,we construct class dependence graph(CDG)networks based on eight practical Java software systems,and apply the procedure of influence maximization to study empirically the correlations between the characteristics of maximum influence and the degree distributions in the software networks.We demonstrate that the artificial nature of CDG networks is reflected partly from the scale free behavior:the in-degree distribution follows power law,and the out-degree distribution is lognormal.For the influence behavior,the expected influence spread of the maximum influence set identified by the greedy method correlates significantly with the degree distributions.In addition,the identified influence set contains influential classes that are complex in both the number of methods and the lines of code(LOC).For the applications in software engineering,the results provide possibilities of new approaches in designing optimization procedures of software systems. 相似文献
997.
LIAO Kai CUI XiaoXin LIAO Nan MA KaiSheng WU Di WEI Wei LI Rui YU DunShan 《中国科学:信息科学(英文版)》2014,(4):269-281
With the technology scaling down, low power dissipation has become one of the research focuses in the field of integrated circuit design. Various types of adiabatic logics have been invented for low-power applications. However, the expanding leakage current degrades the performance of conventional adiabatic logics. In this article, a novel improved complementary pass-transistor adiabatic logic (ICPAL) based on fin-type field- effect transistor (FinFET) devices with ultra-low power dissipation has been presented. The proposed ICPAL takes full advantage of different FinFET operating modes, that is, shorted-gate mode, independent-gate mode, and low-power mode, to make a tremendous reduction in power dissipation. For explication and verification, the power dissipation of different ICPAL standard cells has been investigated and compared with other types of adiabatic circuits based on FinFETs. The results show that the ICPAL circuits have ultra-low power dissipation in a wide range of clock frequencies(30-800 MHz) under the condition of similar number of transistors, and the average reduction in power dissipation is about 23.1%, 75.0%, and 50.0% relative to 2N-2N2P, improved pass- transistor adiabatic logic, and complimentary pass-transistor adiabatic logic, respectively. Furthermore, ICPAL supports a better pre-evaluation of system power dissipation in VLSI design and has an intrinsic characteristic for the resistance to some types of side channel attacks. 相似文献
998.
介绍贵港地区电网基于软分区的三级自动电压控制(AVC)系统,并对该系统的三级控制原理及区域变电站的控制规则进行说明。 相似文献
999.
根据厂区所使用的调节阀自身具备的功能以及生产工艺需求,选择合适的(三断)保位方案,分析了所选择方案的工作原理及优、缺点及适用条件. 相似文献
1000.