PTC型BaTiO3陶瓷的孪晶和孪晶界

用透射电镜和高分辨电镜观察研究了PTC型BaTiO_3陶瓷的孪晶和孪晶界结构,并提出了可能的{111}孪晶及孪晶界的原子结构模型。结果表明,{111}孪晶形成氧八面体共面的共格倾斜孪晶界,在孪晶界处可能存在一定量的A空位且原子密度要低于孪晶体内。同时还发现两种其它特征的孪晶现象。     

定量~(13)C-NMR谱表征蔗渣碱木素结构

从蔗渣纸浆黑液中制出纯蔗渣碱木素，然后测定其定量13C-NMR谱．图谱分析表明，蔗渣碱木素主要由紫丁香基，愈创木基和对羟苯基三种丙烷结构单元组成，其中未绩合的紫丁香基、愈创木基和对羟羊基含量比为2.2：1．0：1．4．蔗渣碱术素结构单元间主要以β-O－4烷基芳基醚键连接，也有一定量的非环状α-醚键存在．蔗渣碱木素中，相当部分对香豆酸类结构并非通过酯键而是通过醚键或碳双键连接于芳核上．     

Modeling of photocatalytic oxidation of VOCs in a packed bed reactor under continuous and discontinuous illuminations

In this paper, a mathematical model is presented to describe the photocatalytic degradation of VOCs in a packed bed reactor. Here, the adsorption of VOCs on the wall of the reactor is taken into account and the diffusion of VOCs in the axial direction is neglected. First-order kinetics is used to describe the photocatalytic oxidation of VOCs. The analytical solution of the present model is obtained by traveling wave method. The solution shows that the reactor performance is totally dependent on the inlet concentration of VOCs when the time is large enough. The present model is validated through the experimental result of the photocatalytic oxidation of trichloroethylene in a packed bed and the predicted results accord well with the experimental data. The influence of flow rate and inlet concentration on the performance of the reactor is discussed in detail. High flow rate offers high reaction rate and low conversion efficiency. The different inlet conditions and different reaction patterns are also investigated. The model would be useful to estimate the rate constant and help to the design of the reactor.     

基于Modbus/TCP协议实现人机界面与下位机通信

在以通用伺服电机控制系统为下位机的基础上,开发了以实时内核μC/OS-II、DSP、CPLD控制模块为核心的软硬件平台。通过移植uIP协议栈到DSP,在通信应用层上将Modbus帧嵌入到TCP帧中,简单可靠地实现了Modbus/TCP协议。同时将Modbus/TCP协议与μC/OS-II实时内核进行整合,更好地保证了系统调度的实时性。     

桌面虚拟化技术在多媒体教室管理中的应用

本文分析了多媒体教室管理的现状,提出通过桌面虚拟化技术解决日常管理中存在的管理难度大、维护人员多、管理效率低等问题,努力提高多媒体教室管理的集中化、安全性和高效率。     

Accommodation and convergence in integral imaging 3D display

In this paper, we analyze the visual fatigue of integral imaging three‐dimensional (3D) display by studying the accommodation and convergence when viewing the integral imaging 3D images. The theoretical analyses show that there is no inconsistency between the accommodation and convergence distances, which means that the integral imaging 3D display has no visual fatigue. Experiments are implemented, and the results finally demonstrate the rationality of the theoretical analyses. These analyses can be quite beneficial for researchers to better understand the performances and promote the practical applications of the integral imaging 3D display.     

Maximum error-bounded Piecewise Linear Representation for online stream approximation

Given a time series data stream, the generation of error-bounded Piecewise Linear Representation (error-bounded PLR) is to construct a number of consecutive line segments to approximate the stream, such that the approximation error does not exceed a prescribed error bound. In this work, we consider the error bound in \(L_\infty \) norm as approximation criterion, which constrains the approximation error on each corresponding data point, and aim on designing algorithms to generate the minimal number of segments. In the literature, the optimal approximation algorithms are effectively designed based on transformed space other than time-value space, while desirable optimal solutions based on original time domain (i.e., time-value space) are still lacked. In this article, we proposed two linear-time algorithms to construct error-bounded PLR for data stream based on time domain, which are named OptimalPLR and GreedyPLR, respectively. The OptimalPLR is an optimal algorithm that generates minimal number of line segments for the stream approximation, and the GreedyPLR is an alternative solution for the requirements of high efficiency and resource-constrained environment. In order to evaluate the superiority of OptimalPLR, we theoretically analyzed and compared OptimalPLR with the state-of-art optimal solution in transformed space, which also achieves linear complexity. We successfully proved the theoretical equivalence between time-value space and such transformed space, and also discovered the superiority of OptimalPLR on processing efficiency in practice. The extensive results of empirical evaluation support and demonstrate the effectiveness and efficiency of our proposed algorithms.     

低碳经济时代企业的社会责任

阐述了低碳经济与企业社会责任的含义,分析了企业社会责任与企业竞争力的关系,提出了在发展低碳经济过程中企业应当承担的社会责任。     

WSN中面向非均匀形状事件的动态检测方案

高效且准确地事件检测与跟踪是无线传感器网络研究的热点问题之一,现有的事件检测方案无法实现对形状不定的区域事件的检测与跟踪,为了解决这一问题,提出了一种改进的动态事件检测和跟踪方案.首先,该方案利用事件质心确定事件的具体位置,然后,考虑了节点的读数强度及该读数与事件质心的距离,提出节点动量概念以引导事件融合和分割检测.仿真实验结果表明,该方案可在各传感器结点中分布式运行,延迟低,能效高,在各种条件下均有很高的准确度.不论事件大小和事件数量如何,它始终可以确定正确的事件数量,给出正确的事件形状.