Distributed Transaction Guarantee Mechanism for In-Memory Data Grid

在线事务处理（online transaction processing，OLTP）应用面临并发量和数据量持续增长的问题，并且高并发读写操作使得后台数据库成为瓶颈。内存数据网格（in-memory data grid，IMDG）是基于内存的新型分布式数据访问平台，是解决系统数据库写操作瓶颈的有效技术途径之一。然而内存数据网格中数据访问操作涉及的数据分布是不可预知的，需要提供分布式事务保障。针对内存数据网格的系统特点，提出了一种分布式事务保障机制，设计实现了事务处理模型、请求处理和数据定位方法以及事务保障协议，并规范化地定义了客户端与服务器端以及服务器端之间的操作接口。在事务处理基准测试TPC-W上的实验结果表明，新机制可以提高在线事务应用的处理速度，并具备良好的扩展性。 Online transaction processing (OLTP) Web applications face the continuous growth of concurrent users and data size. The high concurrent read and write operations make databases become the bottleneck. In-memory data grid (IMDG) is a new distributed data access platform based on memory, and an effective technical approach to elimi-nate the bottleneck of write operation in the database. However data distribution involved in data access operation of IMDG is unpredictable. A distributed transaction guarantee mechanism is necessary. For the IMDG system character-istics, this paper gives a distributed transaction guarantee mechanism, designs and implements a distributed transac-tion processing model, the way to do request processing and data accessing and the transaction guarantee protocol, and normalizes the application programming interface (API) between clients and servers. The experimental results on TPC-W show that the mechanism can improve the OTLP speed and support good scalability.Online transaction processing (OLTP) Web applications face the continuous growth of concurrent users and data size. The high concurrent read and write operations make databases become the bottleneck. In-memory data grid (IMDG) is a new distributed data access platform based on memory, and an effective technical approach to elimi-nate the bottleneck of write operation in the database. However data distribution involved in data access operation of IMDG is unpredictable. A distributed transaction guarantee mechanism is necessary. For the IMDG system character-istics, this paper gives a distributed transaction guarantee mechanism, designs and implements a distributed transac-tion processing model, the way to do request processing and data accessing and the transaction guarantee protocol, and normalizes the application programming interface (API) between clients and servers. The experimental results on TPC-W show that the mechanism can improve the OTLP speed and support good scalability

支持透明集成的数据缓存机制

　　数据缓存是提升动态Web应用性能的重要手段,传统数据缓存方案主要进行数据查询缓存,通常需要开发人员对应用程序进行大量修改并负责缓存失效维护,导致缓存方案的部署成本和维护成本过高.本文提出一种新的数据缓存机制EasyCache,支持缓存数据的自动加载,兼容常用的标准数据访问接口及SQL语法,并提供数据一致性保障策略.开发人员无需修改应用程序即可完成EasyCache的集成.TPC-W基准测试结果表明系统性能得到显著提升,在单表数据规模增加以及并发用户规模增加等情况下,系统响应速度可提高10倍,吞吐率提高近1倍

Mechanism of Self discharge Performance Improvement in the Ni-MH Batteries with NaOH Electrolyte

以NaOH电解液代替KOH能够明显改善MH/N i电池的自放电性能和高温(60℃)充电效率.电化学阻抗和循环伏安测试表明,NaOH电解液的作用可能是改变了H原子于负极表面的吸(脱)附行为,并在一定程度上抑制了负极的析氢过程,从而改善了电池的自放电性能.The self-discharge performance and charge efficiency at 60 ℃ for Ni-MH battery can be markedly enhanced by using NaOH electrolyte instead of KOH electrolyte.Both the results of electrochemical impedance spectroscopy and cyclic voltammetry tests indicate that the separation of H_2 from the negative electrode may be partly blocked in the former because of the change of the adsorption/desorption behavior of H on the surface of the negative electrode,thus results in an improvement of self-discharge performance of the battery.作者联系地址：郑州轻工业学院材料与化工学院,郑州轻工业学院材料与化工学院,郑州轻工业学院材料与化工学院,郑州轻工业学院材料与化工学院 河南郑州450002,河南郑州450002,河南郑州450002,河南郑州450002Author's Address: *,XIA Tong-chi,DONG Hui-chao,WEI Yan-weiDepartment of Material and Chemical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,Henan,Chin

3-RSS与3-RUU同轴驱动布局并联机器人工作空间的对比分析研究

3自由度并联机器人控制简单，结构紧凑，便于设计和研究。为了探究并联机器人关节配置对工作空间大小的影响，以3-RSS与3-RUU两个Tau变种构型并联机器人为研究对象，分别用球铰和虎克铰进行分析，求解了3-RSS与3-RUU同轴驱动布局并联机器人的工作空间。首先，建立机器人简化模型，对其正向运动学进行求解；接着，分析了球铰与虎克铰的运动范围，以此作为关节的约束条件，求解了3-RSS和3-RUU同轴驱动布局并联机器人的三维工作空间，得出工作空间的边界。分析结果表明，同等尺寸大小的3-RUU同轴驱动布局并联机器人比3-RSS同轴驱动布局并联机器人具有更大的工作空间。为后续不同并联机器人的关节选型和工作空间的研究提供了理论和技术的支持

Effects of Oxidation Methods on the Stability of CoOOH Conductive Network in Foam Nickel Electrodes

应用化学氧化(CO)和电化学氧化法(EO)于发泡式镍电极中引入CoOOH导电网络.循环伏安和X射线衍射法研究其还原氧化行为.实验表明,由化学氧化法制备的CoOOH(CO),其电化学还原氧化反应的可逆性优于CoOOH(EO);当镍电极的电位被强制性降低时,前者的结构能够保持稳定.因此,金属氢化物-镍电池经过强制性过放电储存后,于镍电极中引入CoOOH(CO)导电网络的电池容量保持率达到97.7%,而引入CoOOH(EO)导电网络的电池仅为81.4%.Two kinds of the cobalt oxyhydroxide conductive networks in foam nickel electrodes were prepared by different methods i.e.the electrochemical-oxidation(EO) and chemical-oxidation(CO) and which redox behaviors were studied by using cyclic voltammetry and X-ray diffraction measurements.The results show that the CoOOH(CO) has better redox reversibility than CoOOH(EO) and the structure of the former can be kept when nickel electrodes are subjected to a negative potential.Thus,98.7% capacity retention is demonstrated on nickel/metal-hydride batteries with CoOOH(CO) conductive network after being imposed over-discharge state storage;on the contrary,only 83.3% capacity retention is found on the batteries with CoOOH(EO) conductive network.作者联系地址：郑州轻工业学院材料与化工学院,郑州轻工业学院材料与化工学院,郑州轻工业学院材料与化工学院 河南郑州450002,河南郑州450002,河南郑州450002Author's Address: Department of Material and Chemical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,Chin

Fe/Nb多层膜中离子辐照效应研究(英文)

采用磁控溅射技术在Si衬底上沉积Si/[Fe(10 nm)/Nb(4 nm)/Fe(4 nm)/Nb(4 nm)]2/ [Fe(4nm)/Nb(4 nm)]4多层膜。用2 MeV的Xe离子在室温下辐照多层膜。采用俄歇深度剖析、X射线衍射和振动样品磁强计分析辐照引起的多层膜元素分布、结构及磁性变化。AES深度剖析谱显示当辐照注量达到1 .0×1014ions/cm2时,多层膜界面两侧元素开始混合;当辐照注量达到2 .0×1016ions/cm2时,多层膜层状结构消失,Fe层与Nb层几乎完全混合。XRD谱显示,当辐照注量达到1 .0×1014ions/cm2时, Nb的衍射峰和Fe的各衍射峰的峰位相对于标准卡片向小角方向偏移,这说明辐照引起Nb基和Fe基FeNb固溶体相的形成;当辐照注量大于1 .0×1015ions/cm2时,辐照引起非晶相的出现。VSM测试显示,多层膜的磁性随着结构的变化而变化。在此实验基础上,对离子辐照引起界面混合现象的机理进行了探讨