高技术指标：2007年度33国(地区)技术竞争力报告

文中的高技术指标（High Tech Indicators,HTI）为佐治亚理工大学发布的沿用多年的指标。数据对
比的时间段分别为1993年、1996年、1999年、2002/3年和2007年。论文给出了33个国家（地区）当前的竞争
力指标——技术排名(Technological Standing, TS), 同时提供了四个表征未来竞争力前景的主要指标——国家
发展取向指标(National Orientation, NO)、社会经济基础指标(Socio-Economic Infrastructure, SE)、技术基础指
标(Technological Infrastructure, TI)与生产能力指标(Productive Capacity, PC)。论文无意在高技术指标的结果上
多加笔墨,但是也的确注意到,中国已经取代美国占据了技术排名的首位。这一结果反映了高技术指标的特
点,更重要的是,它反映了中国过去15年的惊人发展速度。     

Recent Advance in Non-Krylov Subspace Model Order Reduction of Interconnect Circuits

Model order reduction of interconnect circuits is an important technique to reduce the circuit complexity and improve the efficiency of post-layout verification process in the nanometer VLSI design. Existing works using the Krylov subspace method are very efficient, but the resulting models are less compact and lack global accuracy. Also, existing methods cannot handle interconnect circuits with large input and output ports. Recent advances in reduction techniques using non-Krylov subspace techniques such a...     

氧化钒簿膜电极在锂充电电池中的应用(英文)

鉴于氧化钒是应用于锂充电电池的最有希望的电极材料之一，采用等离子体增强化学气相沉积法（ＰＥＣＶＤ）和激光溅射沉积法（ＰＬＤ），制备了不同的氧化钒薄膜，并研究了它们的电化学性质。这些薄膜具备较高的充放电容量和优良的充放电稳定性。晶体和非晶体的Ｖ２Ｏ５薄膜都可以用ＰＬＤ方法在２００℃和不同的气氛下制备。这些薄膜的充电容量可达３８０ｍＡ·ｈ／ｇ。所制备的最稳定的薄膜是用ＰＥＣＶＤ方法得到的。这些薄膜的Ｏ／Ｖ比很接近Ｖ６Ｏ１３（厚度约为０．５ｕｍ）。它们的放电容量可达４０８ｍＡ．ｈ／ｇ或１２６５ｍＡｈ／ｃｍ３，其能量密度可达９６０．３Ｗ．ｈ／ｋｇ。即使经过４４００次的充放电后，这些薄膜的放电容量仍基本不变。因此，ＰＥＣＶＤ方法及其用它所制备的氧化钒薄膜将是锂充电电池工业很有希望的一种选择。     

Consistency Conditions for Cone-Beam CT Data Acquired with a Straight-Line Source Trajectory

A consistency condition is developed for computed tomography(CT) projection data acquired from a straight-line X-ray source trajectory.The condition states that integrals of normalized projection data along detector lines parallel to the X-ray path must be equal.The projection data is required to be untruncated only along the detector lines parallel to the X-ray path,a less restrictive requirement compared to Fourier conditions that necessitate completely untruncated data.The condition is implemented numeri...     

Rendering Grass Blowing in the Wind with Global Illumination

We have simulated a time varying wind field using the lattice Boltzmann model, and its effect on blades of grass with a simple mass-spring model. We present a global illumination model for multiple scattering of incident sun and sky illumination within the field of grass. We model the grass as a continuous distribution of infinitesimal colored scattering flakes and solve a system of differential equations for the radiance transport. We repeat this for a collection of grass bending directions and amounts, an...     

Dual-Energy Technique at Low Tube Voltages for Small Animal Imaging

We investigate the feasibility of dual-energy method for image contrast enhancement in small animal studies using a low kV X-ray radiographic system.A robust method for X-ray spectrum estimation from transmission measurements,based on expectation-maximization(EM) method,is applied to an X-ray specimen radiographic system for dual energy imaging of a mouse.From transmission measurements of two known attenuators at two different X-ray tube voltages,the X-ray energy spectra are reconstructed using the EM-based...     

Preface:Recent Developments in Semantic Web

<正>The World Wide Web (WWW) has revolutionized many aspects of society in the past two decades.Emerging applications of the World Wide Web have not only fostered industrial     

Emission-Based Scatter Correction in SPECT Imaging

Scatter correction in single photon emission computed tomography(SPECT) has been focused on either using multiple-window acquisition technique or the scatter modeling technique in iterative image reconstruction.We propose a technique that uses only the emission data for scatter correction in SPECT.We assume that the scatter data can be approximated by convolving the primary data with a scatter kernel followed by the normalization using the scatter-to-primary ratio(SPR).Since the emission data is the superpo...     

网络流量测量与CERNET流量监控系统的设计及实现

基于TCP/IP网络的SNMP管理协议,分析了网络流量测量的意义、方法和主要测量技术;针对大型骨干网流量监控和显示的需求,设计完成了CERNET动态流量监控系统,实现了网络流量数据获取,流量分析、实时监控和大屏幕显示播出的功能.     

电流变体单链的轴向应变对导电性质的影响

研究了由平均直径为２１０μｍ的玻璃球在硅油中加直流电场后形成的单链的导电行为，主要研究了链的轴向应变对其导电性质的影响。