总体城市设计产生背景、实施障碍与实施路径

改革开放以来我国城市建设在城市形态和空间方面所存在的城市整体面貌趋同、城市公共空间不足及封闭社区蔓延等问题成为总体城市设计产生的现实背景和动力。在市场经济条件下总体城市设计的目标实现存在着矛盾与障碍,形成独立系统、融入现有规划体系、调整开发与管理模式成为总体城市设计可能的实施路径。     

基于PCI总线的超声射频数据传输系统

为将超声射频数据传输至计算机,在计算机平台下重建超声图像,设计了一个基于PCI总线的超声射频数据传输系统。系统选用PCI9054芯片桥接PCI总线和本地总线,由2片FIFO构成外部缓冲区,PCI总线申请、芯片间的逻辑控制采用CPLD实现,驱动程序用WinDriver驱动开发工具开发。当PCI总线以DMA方式传输超声射频数据时,传输速率高达80MB/s,超声射频数据能够无损、实时地传输至计算机。     

大气波导的形成及其对雷达探测的影响

电磁波在海洋大气条件下传播时可产生大气波导现象。文章分析大气波导的形成以及对电磁波传播的影响,分析大气折射的存在条件,电磁波在大气波导中传播所受到的制约,总结出大气波导对雷达探测的影响。     

多业务并行ATM交换机智能输入端口控制器的研究

本文提出了一种基于多业务并行ＡＴＭ 交换机的智能输入端口控制器。主要功能是为新到达的单播和多播信元在并行多级互连网（ＭＩＮ）中寻找到一条能够成功建立连接的路径。目的是降低信元在并行多级互连网中的阻塞概率,提高交换机的吞吐量     

移动梦网:辉煌与转型

短信成就了移动梦网,移动梦网更进一步促进了短信的大发展。两者的结合促成了i-mode在中国的成功移植,盘活了互联网产业。初步建立了小额支付平台,开中国电信运营业商业模式创新先河。通过对以前问题的整治。移动梦网将面临着一系列的问题,如寻找杀手级应用,商业模式的完善,以及重塑管理环境等。     

A general approach for analysis and application of discretemultiwavelet transforms

This paper proposes a general paradigm for the analysis and application of discrete multiwavelet transforms, particularly to image compression. First, we establish the concept of an equivalent scalar (wavelet) filter bank system in which we present an equivalent and sufficient representation of a multiwavelet system of multiplicity r in terms of a set of r equivalent scalar filter banks. This relationship motivates a new measure called the good multifilter properties (GMPs), which define the desirable filter characteristics of the equivalent scalar filters. We then relate the notion of GMPs directly to the matrix filters as necessary eigenvector properties for the refinement masks of a given multiwavelet system. Second, we propose a generalized, efficient, and nonredundant framework for multiwavelet initialization by designing appropriate preanalysis and post-synthesis multirate filtering techniques. Finally, our simulations verified that both orthogonal and biorthogonal multiwavelets that possess GMPs and employ the proposed initialization technique can perform better than the popular scalar wavelets such as Daubechies'D8 wavelet and the D(9/7) wavelet, and some of these multiwavelets achieved this with lower computational complexity     

1.3 /spl mu/m InGaAsN vertical cavity surface emitting lasers grown by MOCVD

The first InGaAsN VCSELs grown by MOCVD with CW lasing wavelength longer than 1.3 /spl mu/m are reported. The devices were of conventional p-i-n structure with doped DBR mirrors. CW lasing up to 65/spl deg/C was observed, with a maximum output power at room temperature of 0.8 mW for multimode devices and nearly 0.3 mW for single-mode devices.     

Dual-metal gate CMOS technology with ultrathin silicon nitride gatedielectric

We report the first demonstration of a dual-metal gate complementary metal oxide semiconductor (CMOS) technology using titanium (Ti) and molybdenum (Mo) as the gate electrodes for the N-metal oxide semiconductor field effect transistors (N-MOSFETs) and P-metal oxide semiconductor field effect transistors (P-MOSFETs), respectively. The gate dielectric stack consists of a silicon oxy-nitride interfacial layer and a silicon nitride (Si₃N₄) dielectric layer formed by a rapid-thermal chemical vapor deposition (RTCVD) process. C-V characteristics show negligible gate depletion. Carrier mobilities comparable to that predicted by the universal mobility model for silicon dioxide (SiO₂) are observed     

Engineered Elastomer Substrates for Guided Assembly of Complex 3D Mesostructures by Spatially Nonuniform Compressive Buckling

Approaches capable of creating 3D mesostructures in advanced materials (device‐grade semiconductors, electroactive polymers, etc.) are of increasing interest in modern materials research. A versatile set of approaches exploits transformation of planar precursors into 3D architectures through the action of compressive forces associated with release of prestrain in a supporting elastomer substrate. Although a diverse set of 3D structures can be realized in nearly any class of material in this way, all previously reported demonstrations lack the ability to vary the degree of compression imparted to different regions of the 2D precursor, thus constraining the diversity of 3D geometries. This paper presents a set of ideas in materials and mechanics in which elastomeric substrates with engineered distributions of thickness yield desired strain distributions for targeted control over resultant 3D mesostructures geometries. This approach is compatible with a broad range of advanced functional materials from device‐grade semiconductors to commercially available thin films, over length scales from tens of micrometers to several millimeters. A wide range of 3D structures can be produced in this way, some of which have direct relevance to applications in tunable optics and stretchable electronics.