ARM-Linux的底层IO操作的实现研究

随着嵌入式应用的迅猛发展,各种不同的设备广泛应用于嵌入式系统中,通过设置相应的寄存器可以控制设备的工作方式,因此了解嵌入式操作系统在相关平台上的IO操作的实现,对于在嵌入式系统中应用各种设备是至关重要的,本文研究了基于ARM平台S3C2410的嵌入式Linux操作系统的IO操作的实现。     

Effect of Hydrogen on Corrosion and Stress Corrosion Cracking of AZ91 Alloy in Aqueous Solutions

The effect of hydrogen on the corrosion and stress corrosion cracking of the magnesium AZ91 alloy has been investigated in aqueous solutions.Hydrogen produced by corrosion in water diffuses into,and reacts with the Mg matrix to form hydride.Some of the hydrogen accumulates at hydride/Mg matrix(or secondary phase) interfaces as a consequence of slow hydride formation and the incompatibility of the hydride with the Mg matrix(or secondary phase),and combines to form molecular hydrogen.This leads to the development of a local pressure at the hydride/Mg matrix(or secondary phase)interface.The expansion stress caused by hydride formation and the local hydrogen pressure due to its accumulation result in brittle fracture of hydride.These two combined effects promote both the corrosion rate of the AZ91 alloy,and crack initiation and propagation even in the absence of an external load.Hydrogen absorption leads to a dramatic deterioration in the mechanical properties of the AZ91 alloy,indicating that hydrogen embrittlement is responsible for transgulanar stress corrosion cracking in aqueous solutions.     

组成对R2O-CaO-ZnO-Al2O3-SiO2系统分相的影响

通过大量的配方实验和OM,TEM观察,系统研究了R2O－CaO-ZnO-Al2O3-SiO2系统分相与组成间的相互关系,研究结果表明,K2O比Na2O更有利于系统的分相,用Na2O等摩尔取代K2O时,分相区向低铝高硅区收缩,此外,系统分相区大小还明显受到ZnO,CaO相对含量的影响,高锌系统具有更为宽广的分相区,Al2O3对R2O－CaO-ZnO-Al2O3-SiO2系统分相影响呈现出明显的反常现象,在ZnO含量为0．55mol的系统中,当R2O由0．10mol K2O 0.10mol Na2O共同引入时,分相区大小和分相结构尺度都呈现出明显的铝反常现象,而R2O仅由0.20mol K2O引入时,仅分相结构尺度呈现出明显的铝反常现象,反常点的Al2O3含量约为6．20mol%,在一定的热处理条件下,适当增加SiO2的含量有利于系统分相,但当SiO2的含量过高时,分相将由连通结构逐渐转变为孤立相分布于连续基质相中的液滴状结构,甚至消失。     

新型数据管理系统研究进展与趋势

随着各类新型计算技术和新兴应用领域的浮现,传统数据库技术面临新的挑战,正在从适用常规应用的单一处理方法逐步转为面向各类特殊应用的多种数据处理方式.分析并展望了新型数据管理系统的研究进展和趋势,涵盖分布式数据库、图数据库、流数据库、时空数据库和众包数据库等多个领域.具体而言：分布式数据管理技术是支持可扩展的海量数据处理的关键技术;以社交网络为代表的大规模图结构数据的处理需求带来了图数据库技术的发展;流数据管理技术用来应对数据动态变化的管理需求;时空数据库主要用于支持移动对象管理;对多源、异构而且劣质数据源的集成需求催生出新型的众包数据库技术.最后讨论了新型数据库管理系统的未来发展趋势.     

Moving Objects with Transportation Modes: A Survey

Journal of Computer Science and Technology - In this article, we survey the main achievements of moving objects with transportation modes that span the past decade. As an important kind of human...     

Reverse Furthest Neighbors Query in Road Networks

Given a road network G = (V,E), where V (E) denotes the set of vertices(edges) in G, a set of points of interest P and a query point q residing in G, the reverse furthest neighbors (Rfn _R ) query in road networks fetches a set of points p ∈ P that take q as their furthest neighbor compared with all points in P ∪ {q}. This is the monochromatic Rfn _R (Mrfn _R ) query. Another interesting version of Rfn _R query is the bichromatic reverse furthest neighbor (Brfn _R ) query. Given two sets of points P and Q, and a query point q ∈ Q, a Brfn _R query fetches a set of points p ∈ P that take q as their furthest neighbor compared with all points in Q. This paper presents efficient algorithms for both Mrfn _R and Brfn _R queries, which utilize landmarks and partitioning-based techniques. Experiments on real datasets confirm the efficiency and scalability of proposed algorithms.     

Research on gain scheduling controller of the networked control system with long delay

This paper addresses the stabilization and optimization problem of networked control systems (NCSs) with long time delays and parameter scheduling. According to the actual network conditions, the network time delay is divided into the fixed time delay and the random time delay. Then, the stabilization controller and the gain scheduling controller are constructed, where the stabilizing control parameters are obtained with cone complementary linearization (CCL) approach and the optimizing control parameters are solved with estimation of distribution algorithm (EDA). Simulation results demonstrate the effectiveness of the proposed methods.     

Study on degradation of methyl orange using pelagite as photocatalyst

Pelagite of East Pacific Ocean as a low-price, very high reserve photocatalyst, has been successfully used for the first time to realize total degradation and decoloration of methyl orange within 120 min through photocatalysis. The photocatalysis and degradation performance of pelagite for methyl orange under the effect of various factors has been studied. Results show that pelagite has satisfactory photocatalysis effect in degradation of organic compounds.     

基于快速鲁棒相关和粒子滤波器的图像拼接方法

为了在没有预处理和人工干预的情况下自动完成图像拼接，结合快速鲁棒相关与粒子滤波器，提出一种新的图像拼接方法。该方法利用快速鲁棒相关技术所提供的被拼接图像相对位置，作为基于仿射模型粒子滤波器的预测值；使用该预测值，粒子滤波器可简单而有效地估计出图像拼接所需的准确配准参数。实验结果表明：该方法在获得图像配准的全局解的同时，满足鲁棒性、实时性和准确性的要求。     

核糖核酸生产工业化及其在临床上应用的探讨

通过物理化学等方法将微生物中核糖核酸提取出来,并进一步提纯,达到医用水平;对提取工业化及其在临床上的应用作了一定的探讨。