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991.
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
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993.
当前,IT技术及应用正处于向云计算、虚拟化和大数据转型的重要时期,恰当地运用这些新技术,将使我们的工作如同快马加鞭。因此,我们愿意积极探索应用各种IT新技术。 相似文献
994.
随着国内预拌混凝土行业的发展,混凝土企业高层越来越意识到搅拌站信息化管理的必要性,各种混凝土搅拌站ERP软件在国内得到了迅速的发展,通过这种软件的信息化管理,后台数据库每天都会产生大量的生产数据。为了避免搅拌站之间的恶性竞争,混凝土行业协会和政府部门需要对某个区域乃至整个行业的搅拌站的生产运营情况有实时的了解,以便对其进行监管,最终促进行业的公平竞争。本文结合国内混凝土行业自身的特点,阐述了混凝土行业海量数据协同的总体构想和数学模型,之后从多维度论述了基于JCS多级缓存的海量数据协同模块的设计,最后,采用Socket的方式最终实现了Server端与Client端的一对多的数据通信。 相似文献
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996.
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998.
At room temperature atom transfer radical polymerization (ATRP) of N-vinylpyrrolidone (NVP) was carried out using 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra-azacyclo-tetradecane (Me6Cyclam) as ligand in 1,4-dioxane/isopropanol mixture. Methyl 2-chloropropionate (MCP) and copper(I) chloride were used as initiator and catalyst, respectively. The polymerization of NVP via ATRP could be mediated by the addition of CuCl2. The resultant poly(N-vinylpyrrolidone) (PNVP) has high conversion of up to 65% in 3 h, a controlled molecular weight close to the theoretical values and narrow molecular weight distribution between 1.2 and 1.3. The living nature of the ATRP for NVP was confirmed by the experiments of PNVP chain extension. With PNVP-Cl as macroinitiator and N-methacryloyl-N′-(α-naphthyl)thiourea (MANTU) as a hydrophobic monomer, novel fluorescent amphiphilic copolymers poly(N-vinylpyrrolidone)-b-poly(N-methacryloyl-N′-(α-naphthyl)thiourea) (PNVP-b-PMANTU) were synthesized by ATRP. PNVP-b-PMANTU copolymers were characterized by 1H NMR, GPC-MALLS and fluorescence measurements. The results revealed that PNVP-b-PMANTU presented a blocky architecture. 相似文献
999.
The kinetic experiments of Fischer-Tropsch synthesis (FTS) over an industrial Fe-Cu-K catalyst are carried out in a micro-fixed-bed reactor under the conditions as follows: temperature of 493-542 K, pressure of 10.9-30.9 bar, H2/CO feed ratio of 0.98-2.99, and space velocity of 4000-10?000 h−1. The effects of secondary reactions of olefins are investigated by co-feeding C2H4 and C3H6. A detailed kinetics model taking into account the increasingly proven evidence of the olefin re-adsorption mechanism is then proposed. In this model, different sites are assumed for FTS reactions and water gas shift (WGS) reaction, respectively. Rate expressions for FTS reactions are based on the carbide polymerisation mechanism, in which olefin re-adsorption is considered to be a reverse step of olefin desorption reaction. Rate expression for WGS reaction is based on the formate mechanism. An integral reactor model considering both FTS and WGS kinetics is used to describe the reaction system, and the simultaneous estimation of kinetic parameters is conducted with non-linear regression procedure. The optimal model shows that the rate determining steps in FTS reactions proceed via the desorption of hydrocarbon products and the adsorption of CO and the slowest step in WGS reaction is the desorption of gaseous carbon dioxide via formate intermediate species. The activation energies of FTS reactions and WGS reaction are in good agreement with literature values. 相似文献
1000.
关于木素生物降解酶类活力测定问题的讨论 总被引:3,自引:0,他引:3
由于木素结构和生物降解过程复杂多样,全面测定一个菌株的木素降解活力也比较困难,目前已发现三类主要参与木素降解的酶类(LIP、MnP、漆酶),但至今很少有国际上公认的酶活力测定方法,也未见到能把某一菌株木素降解酶类的活力与其在木质纤维材料中降解木素的能力定量关联的报导。本文综合评述了几类主要的木素降解酶类活力测定方法的作用机制和存在的问题,指出一个菌株的木素降解活力是由它的生理特性和总体代谢能力共同决定的,仅由一类或几类酶活力的表现水平难以对其作出确切的评价,从这个角度出发进行研究才能更客现他认识菌株的木素降解活力. 相似文献