Ｄｉｓｔｒｉｂｕｔｅｄ ｓｔｏｒａｇｅ ａｌｇｏｒｉｔｈｍ ｗｉｔｈ ｈｉｇｈ ｐｅｒｆｏｒｍａｎｃｅ ｆｏｒ ｔｈｅ ＵＷＳＮ

为解决无人值守传感器网络的数据存储可靠性问题,提出了一种具有低通信成本和低访问成本的分布式存储算法.算法采用步数为cn的并行定向随机游走机制,将网络中的k个源数据包按照一定的接收概率分散存储到网络中所有的n个节点,在每个节点形成一个存储数据包.理论分析和实验结果表明,基于该算法的存储过程完成之后,即使有部分传感器节点损坏,Sink节点只要随机收集到k+ε,ε大于等于11个存储数据包,就能成功地计算出原来的k个源数据包.与具有代表性的基于LT码的算法相比,文中算法将存储每个源数据包的通信次数从约3nlnn降至约3n;将读取源数据包的节点访问次数从大于k+100降至约k+11.Ｔｏ　ｓｏｌｖｅ　ｔｈｅ　ｄａｔａ　ｓｔｏｒａｇｅ　ｒｅｌｉａｂｉｌｉｔｙ　ｐｒｏｂｌｅｍ　ｏｆ　ｔｈｅ　ｕｎａｔｔｅｎｄｅｄ　ｗｉｒｅｌｅｓｓ　ｓｅｎｓｏｒ　ｎｅｔｗｏｒｋ ｃｏｎｓｉｓｔｉｎｇ　ｏｆ　ｎ　ｓｅｎｓｏｒ　ｎｏｄｅｓ，ｔｈｉｓ　ｐａｐｅｒ　ｐｒｏｐｏｓｅｓ　ａ　ｎｅｗ　ｄｉｓｔｒｉｂｕｔｅｄ　ｓｔｏｒａｇｅ　ａｌｇｏｒｉｔｈｍ　ｂａｓｅｄ　ｏｎ　ｐａｒａｌｌｅｌ ｄｉｒｅｃｔｉｏｎａｌ　ｒａｎｄｏｍ　ｗａｌｋ　ｗｉｔｈ　ｌｅｎｇｔｈｃｎ．Ｔｈｅ　ｐｒｏｐｏｓｅｄ　ａｌｇｏｒｉｔｈｍ　ｄｉｓｓｅｍｉｎａｔｅｓ　ｅａｃｈ　ｏｆ　ｋｓｏｕｒｃｅ　ｄａｔａ　ｐａｃｋｅｔｓ ｉｎ　ｔｈｅ　ｎｅｔｗｏｒｋ　ａｃｃｏｒｄｉｎｇ　ｔｏ　ａ　ｇｉｖｅｎ　ｐｒｏｂａｂｉｌｉｔｙ　ａｎｄ　ｆｏｒｍｅｓ　ａ　ｓｔｏｒｅｄ　ｄａｔａ　ｐａｃｋｅｔ　ｉｎ　ｅｖｅｒｙ　ｎｏｄｅ．Ｓｉｍｕｌａｔｉｏｎ ｒｅｓｕｌｔｓ　ｓｈｏｗ　ｔｈａｔ，ａｆｔｅｒ　ｔｈｅ　ｓｔｏｒａｇｅ　ｐｒｏｃｅｓｓ　ｂａｓｅｄ　ｏｎ　ｔｈｅ　ｐｒｏｐｏｓｅｄ　ａｌｇｏｒｉｔｈｍ　ｉｓ　ｃｏｍｐｌｅｔｅｄ，ｅｖｅｎ　ｉｆ　ｓｏｍｅ ｓｔｏｒｅｄ　ｄａｔａ　ｐａｃｋｅｔｓ　ａｒｅ　ｍｉｓｓｉｎｇ，ｔｈｅ　ｄａｔａ　ｃｏｌｌｅｃｔｏｒ　ｎｏｄｅ　ｃａｎ　ｓｕｃｃｅｓｓｆｕｌｌｙ　ｒｅｃｏｖｅｒ　ｔｈｅ　ｋｓｏｕｒｃｅ　ｄａｔａ　ｐａｃｋｅｔｓ ｆｒｏｍ　ａｎｙ　ｓｕｒｖｉｖａｌ　ｋ＋ε，ε≥１１ｓｔｏｒｅｄ　ｄａｔａ　ｐａｃｋｅｔｓ．Ｃｏｍｐａｒｅｄ　ｗｉｔｈ　ｔｈｅ　ＬＴ　ｃｏｄｅｓ　ｂａｓｅｄ　ａｌｇｏｒｉｔｈｍ，ｔｈｅ ｐｒｏｐｏｓｅｄ　ａｌｇｏｒｉｔｈｍ　ｒｅｄｕｃｅｓ　Ｓｉｎｋ　ｎｏｄｅｓ　ｑｕｅｒｙ　ｃｏｓｔ　ｆｒｏｍ　ｋ＋１００ｔｏ　ｋ＋１１ａｎｄ　ｒｅｄｕｃｅｓ　ｔｈｅ　ｎｅｔｗｏｒｋｓ ｃｏｍｍｕｎｉｃａｔｉｏｎ　ｃｏｓｔ　ｆｒｏｍ　３ｎｌｎｎｔｏ　３ｎ

Application of laser scanning confocal microscope in micro-electro-mechanical system

研究了激光共焦扫描显微镜(LSCM)在微结构分析中的应用,综述了该项应用的优势。LSCM的高分辨率和光强调节功能,使其可用于大角度测量;与图像处理系统相结合,便于微结构的定性和定量分析;而全自动样片台沿X轴和Y轴的自动扫描实现了图像的拼接功能。实验结果表明:运用LSCM测量的斜面最大角度至少可以达到50°;在悬臂梁的形貌分析中,可获得清晰的三维形貌,同时通过二维定量分析精确测得其形变为3.145μm;在100×物镜下,运用拼接功能获得384μm×288μm的视场面积,解决了高放大倍数下,在单帧显微图像中无法获取所观测对象全貌的问题。LSCM在微结构分析中的应用弥补了其它形貌分析设备测量功能上的不足,提升了微机电系统的测试水平。An application of Laser Scanning Confocal Microscope (LSCM) in micro-structure analysis was discussed in order to enhance the analyzing and measuring levels of micro structure.LSCM could be used to measure large angle because of its high resolution and adjustable light intensity,and could analyze the micro structure by combining with picture disposal system qualitatively and quantitatively,also its full-automatic sample stand could automatically scan along X axis and Y axis to realize a picture mosaic.The experimental results indicate that the maximum slope angle measured by LSCM reaches at least 50°,and the clear three dimensional profile is obtained in the profile analysis of cantilever.Meanwhile,the deformation accurately measured by two dimensional quantitative analysis is 3.145 μm,and the field area is 384 μm×288 μm in mosaic function equipped with LSCM in 100× objective,which can solve the problem that the watched object's total shape in single frame micrographic image can not be obtained under high microscopic enlargement times.Experimental results show that the LSCM can make up for measuring functional deficiency of other profile analytic equipment and can improve the testing level of MEMS.厦门大学科技创新预研基金资助项目(No.Y07002

Low Computational Optimization Method in the Binary Vandermonde Coded Storage Systems

针对二进制范德蒙码的编码存储与译码重构过程,提出了一种降低相关编译码过程计算量的优化方法。该方法根据二进制编译码矩阵行向量中"1"的分布以及各向量之间"1"的相互位置关系,最终确定出二进制编译码矩阵所对应的各个校验块的计算次序,从而实现降低整个编码过程或译码过程计算量的目的。实验表明,该方法可以降低30%左右的相关计算量,同时,该优化方法可以推广应用到其他二进制编码存储系统中

Portable low-power-dissipation tag used for real-time positioning system and positioning method based on tag

本发明公开了一种用于实时定位系统的便携式低功耗标签及其定位方法，该标签包括电源管理电路、数据处理控制电路、射频网络匹配电路、低噪声功率放大电路、第一射频收发通道转换电路、第二射频收发通道转换电路以及带通滤波电路。电源管理电路为整个标签系统进行供电。数据处理控制电路用于实现定位信息的处理；射频网络匹配电路用于实现定位信息交互；低噪声功率放大电路用于实现射频信号的功率放大；第一、第二射频收发通道转换电路用于实现射频发射、接收信号通道的转换；带通滤波电路用于实现射频信号的滤波处理。本发明功耗低、尺寸小，十分轻便，具有可穿戴性，方便定位人员携带，满足多场合的定位需求

Passivation Behavior of Aluminum Alloy during Electrochemical Machining and Its Effects on the Machining Performance

本文研究与分析了铝合金电解加工过程的钝化行为，探讨了加工电压、电流密度、加工间隙及电解液成分等因素对电解加工性能的影响. 研究表明，在试验温度（23 ± 1）oC下，铝合金在NaNO3和NaF复合电解液体系（钝化电解液）存在钝化现象，钝化降低了电解加工的电流效率，并使电流效率随电流密度发生较大变化. 同时，钝化也使间隙特征曲线负移. 而在相同浓度NaCl和NaF复合电解液体系（活化电解液）电解加工，可在很宽的电位范围内保持活性溶解. 在钝化电解液中，电解加工表面更加平整.The passivation behavior of aluminum alloy during electrochemical machining was investigated and discussed. The effects of processing voltage, current density, space of electrodes and electrolyte composition on electrochemical machining performance were explored. The results indicate that the electrochemical machining aluminum alloy in the composite electrolyte system containing NaNO3 and NaF existed passivation phenomenon. Passivation action decreaseed the current efficiency and made it varied greatly with the current density. Also the passivation shifted the interspace characteristic curve of electrode notably to a negative direction. There was not passivation phenomenon in the composite electrolyte system containing the same concentrations of NaCl and NaF for the electrochemical machining of aluminum alloy. It kept active dissolution in a wide range of potential. More uniform machining surface could be obtained in passive electrolyte.国家自然科学基金项目 (No. 21263017，No. 91023047) 及轻合金加工国防科技重点学科实验室基金和江西省工业支撑项目基金资助作者联系地址：南昌航空大学 轻合金加工国防重点学科实验室，材料科学与工程学院，江西 南昌 330063Author's Address: School of Material Science & Engineering, Nanchang Hangkong University, National Defense Key Laboratory of Light Alloys Processing Science and Technology, Nanchang 330063, China通讯作者E-mail：[email protected]

固态发酵预处理木屑对其制备成型燃料的影响

We pretreated sawdust（Castanopsis fissa Rehd.et Wils） by solid state fermentation（SSF） with Phanerochaete chrysosporium, and then compressed it into pellets with the moisture content of 15% and the pressure of 98 MPa, to solve the problem of low density

Effect of pretreatment by solid-state fermentation of sawdust on the pelletization and pellet＇s properties

We pretreated sawdust（Castanopsis fissa Rehd.et Wils） by solid state fermentation（SSF） with Phanerochaete chrysosporium, and then compressed it into pellets with the moisture content of 15% and the pressure of 98 MPa, to solve the problem of low density

大连极紫外相干光源

先进光源的发展在前沿科学研究中发挥的作用越来越重要。近十年来,飞速发展的自由电子激光技术为科学家们提供了探索未知世界、发现新科学规律和实现技术变革的重要工具。建成的大连极紫外(EUV)相干光源的运行波段为50~150nm,单脉冲能量大于100μJ,且可提供10-12 s和10-13 s量级的超快激光脉冲,是我国第一台自由电子激光用户装置,并且是国际上唯一运行在极紫外波段的自由电子激光用户装置,在世界范围内为用户提供具有高峰值亮度和超短脉冲的极紫外激光。大连EUV相干光源是由国家自然科学基金委资助、由中国科学院大连化学物理研究所和上海应用物理研究所共同承担的重大科学仪器研制项目,目标是打造一个以先进极紫外光源为核心、主要用于能源基础科学研究的光子科学平台