CMTD晶体的二维核叠层生长现象

在用原子力显微镜对有机非线性光学晶体CdHg(SCN)4(H6C2OS)2(CMTD)的研究过程中,发现了一种单二维核叠层生长现象,即整个晶体由一个二维核叠层生长丘发展而成.这种生长现象无法用经典的二维核模型解释,于是给出另一种二维核生长模型--二维核叠层模型(terraced nuclear model).二维核叠层模型是传统二维核晶体生长模型的补充.     

电刺激小脑顶核治疗脑梗死的临床观察及护理

探讨和观察电刺激小脑顶核治疗脑梗死的疗效。方法 :96例脑梗死患者随机分为治疗组和对照组各 48例 ,治疗组患者在常规药物综合性治疗的基础上 ,同时接受电刺激小脑顶核治疗 ,治疗 1 0d后 ,观察其疗效。结果 :治疗组有效率为 94% ,对照组有效率 87%。两组比较差异具有显著性。结论 :常规药物加电刺激小脑顶核治疗脑梗死有明显疗效 ,有利于患者神经功能的早期康复     

Die ersten Bor(III)-di(organosulfonyl)amide: Ein neuartiger B(OS)2N-Sechsring und zwei Aminoboran-Strukturen mit langen B–N-Bindungen

Polysulfonylamines. XCIX. The First Boron(III) Di(organosulfonyl)amides: A Novel B(OS)₂N Six-Membered Ring and Two Aminoborane Structures with Long B–N Bonds Ph₂B[N(SO₂Me)₂] ( 1 ) and the benzo-1,3,2-dioxaboroles C₆H₄O₂BN(SO₂R)₂, where R = Ph ( 2 a ) or Me ( 2 b ), were prepared by treating the appropriate bromoboranes with Me₃SiN(SO₂Me)₂ and/or AgN(SO₂R)₂. Their crystal and molecular structures were determined by low-temperature X-ray diffraction ( 1 : monoclinic, space group P2₁/n; 2 a : monoclinic, P2₁/c; 2 b : triclinic, P 1, structure marred by disorder of one MeSO₂ group). The B atom of 1 features a distorted tetrahedral coordination formed by the ipso-C atoms of the Ph groups and two O atoms of the 1,5-chelating (MeSO₂)₂N⁷ anion (B–O 156.5, 157.7 pm). The resulting six-membered B(OS)₂N ring adopts a boat conformation, B and N lying out of the plane of the other four atoms. In the chelate ligand, which is severely distorted from the common pseudo-C₂ symmetry of the discrete anion, extremely long S–O(B) bonds (151.2, 151.7 pm) are compensated by short N–S bonds (156.1, 156.8 pm). Molecules 2 a and 2 b have aminoborane structures with trigonal-planar coordinations at B and N, unusually long B–N distances suggesting single bonds [ 2 a : 147.6(3), 2 b : 146.3(5) pm], and fairly short N–S bonds ( 2 a : av. 167.4, 2 b : av. 170.4 pm). In 2 a the O₂B plane is twisted by 70.9° vs. the NS₂ plane, whereas the O₂B–NS₂ moiety of 2 b is approximately coplanar (twist-angle ca. 9°).     

基于ARM的指纹采集仪的设计与实现

指纹采集仪是一个涉及多个功能模块和技术参数的指纹识别仪器。以Samsung公司的嵌入式32位ARM器件S3C2440为主控CPU,结合大容量SDRAM,NAND Flash,彩色LCD,USB,Windows CE操作系统,设计了指纹采集的硬件和软件系统,采集到指纹图像并分析采集结果,该系统满足采集范围广,体积小,功耗小,储存能力强,成本低等设计要求,并且采用窗口式显示形式,便于仪器的调试,系统灵活性强。为实现指纹识别软件提供了功能强大的硬件基础,对研究速度快,性价比高的嵌入式指纹平台具有重要的参考价值。     

A semantic hierarchy for intuitionistic logic

Brouwer’s views on the foundations of mathematics have inspired the study of intuitionistic logic, including the study of the intuitionistic propositional calculus and its extensions. The theory of these systems has become an independent branch of logic with connections to lattice theory, topology, modal logic, and other areas. This paper aims to present a modern account of semantics for intuitionistic propositional systems. The guiding idea is that of a hierarchy of semantics, organized by increasing generality: from the least general Kripke semantics on through Beth semantics, topological semantics, Dragalin semantics, and finally to the most general algebraic semantics. While the Kripke, topological, and algebraic semantics have been extensively studied, the Beth and Dragalin semantics have received less attention. We bring Beth and Dragalin semantics to the fore, relating them to the concept of a nucleus from pointfree topology, which provides a unifying perspective on the semantic hierarchy.     

分区操作系统下的BIT软件的设计

针对原有的自测试软件在分区操作系统下不能被分区内应直接使用的问题,本文提出了一种分层的BIT软件的实现方法解决该问题。分区操作系统是新一代综合化航电系统的基础,提供时间分区和空间分区机制,保证综合后的应用不会相互影响。分区操作系统带来了软件结构的变化,应用软件运行在用户态,而自测试软件通常由于需要操作硬件运行在系统态,原有的自测试软件不能满足要求。     

交换机应用软件升级对操作系统的补充

介绍S1240程控电话交换机在应用程序软件升级中，对操怍系统的支持和朴充。     

STLite/OS20嵌入式实时操作系统原理及其应用

STLite/OS20是用于数字电视机顶盒中的嵌入式操作系统,具有实时、多任务等特点.介绍了该操作系统的内核、存储器管理和分区、分配策略、多任务调度及任务间通过信号量和消息处理进行通信的机制、中断管理等.     

基于DMCU的可移动多媒体平台设计

基于骏亿DMCU板开发的多媒体系统，采用多线程方式。通过DMCU板的GPIO扩展了USB通讯模块，利用义统ET44M210板实现与电脑高速通信，可以很方便的下栽视音频文件及将信息实时反馈。用户可以从本地（DMCU板）程序界面选择要使用的多媒体功能，同时在运行上位机程序时能对平台内多媒体文件进行更新和控制。平台的信息（如摄像头采集图像）也可以实时发放回上位机。     

Novel Peak‐to‐Average Power Ratio Reduction Methods for OFDM/OQAM Systems

The tone reservation method is one of the most effective pre‐distortion methods for peak‐to‐average power ratio reduction in orthogonal frequency division multiplexing (OFDM) systems. Its direct application to OFDM systems with offset quadrature amplitude modulation (OQAM) is, however, not effective. In this paper, two novel TR‐based methods are proposed, specifically designed for OFDM/OQAM systems by taking into consideration the overlapping nature of OQAM signals. These two methods have different approaches to the generation of the peak‐cancelling signal. The first one (overlapped scaling tone reservation) generates the peak‐cancelling signal using a least squares approximation algorithm with possible adjacent symbol overlap; the second one (multi‐kernel tone reservation) generates the peak‐cancelling signal by using multiple impulse‐like time domain kernels. It is shown by simulation that, when used in OFDM/OQAM systems, the proposed methods can provide better performance than the direct application of the existing controlled clipping tone reservation method, and even outperform the multi‐block tone reservation method.