双奇核~(128)Ⅰ的高自旋态

利用重离子熔合蒸发反应124Sn(7Li,3n)布居了双奇核128I的激发态.基于标准在束γ谱学实验测量结果,扩展并更新了128I原有能级纲图.根据已有的高自旋态核结构知识,通过系统学比较和分析,指出了基于π(g7/2/d5/2)vh11/2组态的负宇称能级结构和πh11/2πh11/2组态的正宇称能级结构.     

A Study on System Availability Vs System Administration Efforts with Mathematical Models

Abstract: Two mathematical models are developed in this paper to study the effectiveness of system administration effortson the improvement of system availability, based on the assumption that there exists a transitional state for a computer sys-tem in operation before it is brought down by some hardware or software problems and with intensified system administra-tion efforts, it is possible to discover and fix the problems in time to bring the system back to normal state before it isdown. Markov chain is used to simulate the transition of system states. A conclusion is made that increasing system admin-istration efforts may be a cost-effective way to meet the requirements for moderate improvement on system availability, buthigher demand on this aspect still has to be met by advanced technologies.     

2009中国有效专利年度报告

基于2009年我国有效专利的统计数据,使用国内外分布、专利权人类型分布、维持年限、技术领域、地区分布等不同维度对当前有效专利进行分析研究,并对我国有效专利的主要特点进行总结.     

MCC: A Message and Command Correlation Method for Identifying New Interactive Protocols via Session Analyses

Traffic classification is critical to effective network management. However, more and more proprietary, encrypted, and dynamic protocols make traditional traffic classification methods less effective. A Message and Command Correlation (MCC) method was developed to identify interactive protocols (such as P2P file sharing protocols and Instant Messaging (IM) protocols) by session analyses. Unlike traditional packet-based classification approaches, this method exploits application session information by clustering packets into application messages which are used for further classification. The efficacy and accuracy of the MCC method was evaluated with real world traffic,including P2P file sharing protocols Thunder and BitTorrent, and IM protocols QQ and GTalk. The tests show that the false positive rate is less than 3% and the false negative rate is below 8%, and that MCC only needs to check 8.7% of the packets or 0.9% of the traffic. Therefore, this approach has great potential for accurately and quickly discovering new types of interactive application protocols.     

Preparation and characterization of microcapsule containing epoxy resin and its self-healing performance of anticorrosion covering material

Microencapsulated healing agents that possess adequate strength,long shelf-life,and excellent bonding to the host material are required for self-healing materials. The in situ encapsulation method is demonstrated over an order of magnitude size reduction for the preparation of urea-formaldehyde(UF) capsules filled with a healing agent,a mixture epoxy resin of the epoxy 711 and E-51. Capsules with diameters as small as about 100 μm are achieved under the agitation rate of 800 r min-1. The capsules possess a uniform UF shell wall(4 μm average thickness) . By using the analysis of scanning electronic microscope(SEM) ,thermal analysis(TG-DTA) and FTIR,the characteristics of the microcapsules were investigated respectively. Successful self-healing has been demonstrated for anticorrosion covering materials with microcapsules.     

Diameter-controlled growth of aligned single-walled carbon nanotubes on quartz using molecular nanoclusters as catalyst precursors

Molecular nanoclusters containing Fe and Mo atoms have been used as catalyst precursors for the growth of single-walled carbon nanotubes (SWNTs) on stable temperature (ST)-cut quartz substrates by chemical vapor deposition. Attribute to the uniform catalyst nanoparticles and the confinement effect of the crystalline substrates, well-aligned SWNTs with narrow diameter distribution have been synthesized. Atomic force microscopy measurements show that the mean diameter of the nanotubes obtained by thermal decomposition of ethanol at 900°C is 0.76 ± 0.16 nm, which is the smallest among all reported results for aligned SWNTs. The mean diameter of the nanotubes increases with growth temperature. In addition to using identical nanoclusters as the catalyst precursors, the avoidance of annealing treatment of catalyst precursors is also a key point for obtaining SWNTs with controlled diameters. Using these identical nanoclusters as catalyst precursors and carefully tuning the growth parameters make us closer to the ultimate goal of controlling the chirality of SWNTs.     

GSM Co-Channel and Adjacent Channel Interference Analysis and Optimization

Most current Global System for Mobile Communications (GSM) frequency planning methods evaluate the interference and assign frequencies based on measurement reports.Assigning the same or adjacent frequencies to cells close to each other will introduce co-channel and adjacent channel interference which will reduce network performance.Traditionally,man power is used to check and allocate new frequencies which is time consuming and the accuracy is not satisfactory.This paper presents an intelligent analysis met...     

板坯连铸二次冷却过程动态交互式仿真系统

连铸二次冷却过程控制水平的提高对提高连铸坯的质量和产量具有重要作用。为研究二次冷却设定控制算法,把铸流切片的生命周期模型与凝固传热模型相结合,对非线性热物性参数与凝固潜热进行处理,建立了二次冷却过程的动态仿真模型;并以此为基础研制了动态交互式仿真软件系统。系统由虚拟二次冷却对象、控制算法、监控操作、平台管理四个子系统组成;能够对板坯和方坯在非稳态浇铸工况下铸流的凝固过程进行仿真,得出暂态和稳态全过程的铸流内部温度场、凝固坯壳厚度、凝固终点位置、液相穴形状等的变化过程;给出二次冷却过程对输入与扰动信号的动态响应。系统在仿真过程中的人机交互、可移植性方面做了专门设计,为深入研究和优化二次冷却设定控制算法提供了有力的实验平台。仿真模型与仿真软件系统成功应用于某钢企二次冷却与轻压下设定控制系统的研制、测试与在线运行。     

Radar Sea Clutter Suppression and Target Indication with a Spatial Tracking Filter

It is an important issue to study sea clutter suppression because it could interfere with the detection of targets above the sea surface severely. Spatial spectrum analyses show that the majority of sea clutter has low-frequency characteristics, compared to the high-frequency characteristics of the targets. This paper proposes a frequency-based spatial tracking filter to suppress sea clutter to facilitate targets identification. Experimental results show that the signal-to-clutter ratio can increase by more...     

Encumbering the intramolecular π donation by using a bridge: A strategy for designing metal-free compounds to hydrogen activation

On the basis of the FLP (frustrated Lewis pair) principle, a new strategy has been proposed to construct the frustration in de- signing metal-free hydrogen activation compounds, by using FMO (frontier molecular orbital) analyses and quantum mechanics calculations. Unlike the known FLPs which use bulky substituents to prevent them from forming stable Lewis acid/base com- plexes, the new approach encumbers the intramolecular π donation from the electron donor to the acceptor (e.g. in BH2NH2) by using a CH2 br...