Polymeric N‐allyl vinylpyridinium salts as addition–fragmentation type initiators for cationic polymerization

Polymeric allyl pyridinium salts were synthesized from styrene and 4‐vinyl pyridine copolymers by quaternization and counteranion exchange reactions. The initiation capability of these copolymers, in conjunction with a photochemical free radical source such as benzoin, via an addition –fragmentation mechanism in the cationic polymerization of cyclohexene oxide is investigated. © 2001 Society of Chemical Industry     

宏观事故总量发展趋势的规律探索及模型研究

为研究现代技术管理条件下宏观事故总量发展趋势的规律,选取企业、行业及国家层面的典型宏观事故统计量随时间的变化关系为研究对象,以数学建模的分析模式对比其中规律,并借助马尔萨斯人口学指数规律模型对机理进行描述和解释.结论表明:在一定时间区域内,国家、行业及企业各层面宏观事故总量y的发展随时间x呈指数递减趋势,其回归函数通式可用y=ae^rx表示,且各回归曲线的判定系数R²值证实指数规律相关关系显著.宏观事故总量的发展趋势可能呈现出分段现象,各段存在明显边界的同时,各自仍保持稳定的指数递减规律变化.利用这一规律,通过确定某一宏观事故总量发展趋势的回归函数的方法,可对未来一段时间内的该宏观事故总量值进行预测.     

Heuristics based server consolidation with residual resource defragmentation in cloud data centers

Server Consolidation is one of the foremost concerns associated with the effective management of a Cloud Data Center as it has the potential to accomplish significant reduction in the overall cost and energy consumption. Most of the existing works on Server Consolidation have focused only on reducing the number of active physical servers (PMs) using Virtual Machine (VM) Live Migration. But, along with reducing the number of active PMs, if a consolidation approach reduces residual resource fragmentation, the residual resources can be efficiently used for new VM allocations, or VM reallocations, and some future migrations can also be reduced. None of the existing works have explicitly focused on reducing residual resource fragmentation along with reducing the number of active PMs to the best of our knowledge. We propose RFAware Server Consolidation, a heuristics based server consolidation approach which performs residual resource defragmentation along with reducing the number of active PMs in cloud data centers.     

Impact of regulatory rules on economic performance of PV power plants

The rapid growth of Renewable Energy Sources (RES) power plants connected to the grid has introduced new problems related to the safe and reliable operation of the electricity network from transmission to distribution sectors. New regulatory rules can promote RES producers to make a commitment on the energy amount that is likely to be supplied to the network. The present paper concerns the analysis of the energy production of a PV power plant from the economic point of view, with reference to the presence of regulatory rules. Costs of penalty and value of energy are compared, in order to evaluate the economic efficiency of the plant. Use of auxiliary energy storage devices is investigated, with the aim to determine the relevant dimensions that increase the economic efficiency of the PV plant. A software instrument that implements these algorithms is described and applied to a case study.     

无线传感器网络中一种高效的能量汇报融合机制

通过对telosb节点能耗规律的分析,建立能量预测模型（EFM）采用差介阈值融合汇报机制（DTARM）能够显著减少能量数据汇报次数,提高数据收集效率,降低能耗。实验表明：预测模型的预测成功率为70％-85％,采用差分-阈值融合汇报机制后能使节点的寿命延长5％-11％。     

Google map的数据管理和表现机制的讨论研究

Google作为全球最大的搜索引擎,将GoogleMap加入其服务范围内,它集成了全球不同分辨率的遥感图像。Ajax技术改变了传统的客户端与服务器端进行交互的方式,进一步提高了GoogleMap的友好交互界面,增强了其服务质量。     

基于聚类和模糊神经网络的装备维修费用预测

在对装备使用维修费用分析的基础上,利用聚类和模糊神经网络理论,建立了时间序列对象的预测模型,并应用于装备使用维修费用的预测研究,从而探讨了一条适合装备使用维修费用预测的新途径。通过对某型装备使用维修费用的预测分析,证实了本模型的科学性与正确性。     

焦炭强度指标间关系探讨

焦炭的冷态强度测定周期较短?成本低廉,而热态性能测定周期相对较长?成本昂贵。因此,利用焦炭冷态强度预测热态性能,不但对指导焦化生产具有一定的意义,而且利用各强度指标间的关系可以检验实际测量数据是否存在异常值。     

One‐step synthesis of triarm block copolymers via simultaneous reversible‐addition fragmentation chain transfer and ring‐opening polymerization

One‐step synthesis of star copolymers by reversible addition–fragmentation chain transfer (RAFT) and ring‐opening polymerization (ROP) by using a novel dual initiator is reported. Triarm block copolymers comprising one polystyrene (or polyacrylamide) arm and two poly(β‐butyrolactone) arms were synthesized in one‐step by simultaneous RAFT polymerization of styrene (St) (or acrylamide, designated as AAm) and ROP of β‐butyrolactone (BL) in the presence of a novel trifunctional initiator, 1,2‐propanediol ethyl xanthogenate (RAFT‐ROP agent). This dual initiator was obtained through the reaction of 3‐chloro‐1,2‐propanediol with the potassium salt of ethyl xanthogenate. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one‐step polymerization reaction were evaluated. The characterization of the products was achieved using Fourier‐transform infrared spectroscopy (FTIR), ¹H‐nuclear magnetic resonance (¹H‐NMR), ¹³C‐nuclear magnetic resonance (¹³C‐NMR), Gas chromatography–mass spectrometry (GC–MS), gel‐permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (γ) techniques. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

纵筋板轧制技术的研究现状与展望

纵筋板是在钢板的某一表面上均布纵向凸筋的一类异型钢板,其轧制过程是兼有板带和型钢变形特征的成形过程,局部具有严重畸变。本文介绍了纵筋板及其主要用途,以及国内外学者对纵筋板轧制理论和实验研究的现状。总结了筋底压下率、轧制温度、坯料厚度、轧制力以及板宽等因素对成筋率的影响。同时,对纵筋板研究与应用的前景进行了展望。