16kbit 非易失铁电 RAM 芯片 FM25C160 及其应用

FM25C160是美国Ramtorn公司生产的非易失性铁电介质读写存储器FRAM。文中介绍了该芯片的性能特点、管脚定义、内部结构和工作原理。给出了FM25C160和AT89C52单片机所构成的具有掉电保护和写保护功能的应用系统，同时给出了对FM25C160芯片进行读写操作的应用程序。     

一种新型的X.25网络—分组无线数据网络

本文介绍了一种新型的Ｘ．２５网络－分组无线数据网，并介绍了其构成方式及应用范围。     

THE SIZE OF PLASTIC ZONES AND FATIGUE CRACK GROWTH BEHAVIOUR OF THREE FORMS OF A Ti–6Al–2.5Mo–1.5Cr ALLOY

The effect of microstructure on the fatigue properties of Ti–6Al–2.5Mo–1.5Cr alloy was investigated. The experimental results for both the fatigue crack initiation and propagation behaviour, as well as the dynamic fracture toughness ( K _Id ) showed clearly that a lamellar microstructure is superior to two other structures. It was found that, as in the case of steels, the initiation and subsequent growth of cracks in the titanium specimens with a sharp notch may also occur on loading levels below the threshold values of the K factor (Δ K _th ) determined for long fatigue cracks. In addition, measurements by interferential-contrast of the plastic zone size on the surface of specimens revealed that the different rate of crack growth at identical values of Δ K in individual structural states can roughly be correlated with the size of the plastic zone. A general relationship between the fatigue crack growth rate and plastic zone size, the modulus of elasticity and the role of crack tip shielding is discussed.     

Optimal periodic inspection of a deterioration process with sequential condition states

The condition of components subject to visual inspections is often evaluated on a discrete scale. If at each inspection a decision is made to do nothing or to perform preventive or corrective maintenance, the proposed decision model allows us to determine the optimal time between periodic inspections, such that the expected average costs per unit of time are minimized. The model which describes the uncertain condition over time is based on a Markov process with sequential phases. The key quantities involved in the model are the probabilities of having to perform either preventive or corrective maintenance before or after an inspection. The costs functions for two scenarios are presented: a scenario in which failure is immediately detected without the need to perform an inspection and a scenario in which failure is only detected by inspection of the object. Analytical results for a special case and algorithmic results for a broad class of Markov processes are derived. The model is illustrated using an application to the periodic inspection of road bridges.     

On Solving Periodically Perturbed Nonconservative Systems with a One-Parameter Embedding

The paper is concerned with solving the periodically perturbed nonconservative systems, which will be differentiably imbedded into an one-parameter family of operators. The solution of the systems is then found by continuing the solution curve of operator homotopy. When the Newton-Kantorovich's procedure is applied to the corresponding operator equations, an efficient algorithm is derived. Furthermore, the suitable condition on the optimum step size of the parameter is provided for assuring that the approximation solution will converge to the unique solution of the nonlinear periodically boundary value problem. Finally, the theoretical results are in excellent agreement with the numerical examples. Received August 14, 2001; revised December 19, 2001 Published online: November 18, 2002     

基于TMS320DSC25的网络摄像机

首先从大环境下介绍产品的市场前景,再从现有的视频压缩编码及可采用的硬件结构来选择最合适的能实现手机监看功能的网络摄像机的压缩算法和硬件结构.并提出采用以MPEG-4为视频压缩编码、TMS320DSC25为硬件核心的一种能实现手机监控的网络摄像机的硬件架构.本网络摄像机是将前端摄像机、个人电脑、网络服务器的功能整合在一起,为无线终端用户提供视频服务,实现远程多点监控.     

铸态Al63Cu25Fe12的热处理及相分析

按照原子比Al63 Cu2 5Fe12 配料 ,在真空感应炉中熔炼制备AlCuFe准晶材料样品。通过对铸态Al63 Cu2 5Fe12 的不同温度的热处理得出不同的处理温度对其内部相的转变情况 ,发现随着温度的升高 ,铸态Al63 Cu2 5Fe12 向准晶相的转变越来越充分 ,成分趋于单一化     

Synthesis, Characterization and Photocatalytic Activity of Titania Loaded Cd-MCM-41

Catalysts consisting of cadmium incorporated into MCM-41 mesoporous molecular sieves (Cd-MCM-41) with Si/Cd = 80 have been synthesized by the hydrothermal method using cadmium acetate as the source of cadmium. This was then loaded with titania via the sol-gel method to explore the photoactivity in UV light. These two materials were characterized by various physicochemical techniques such as N₂ physisorption, O₂ chemisorption, diffuse reflectance UV-vis, X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS). The pore size of the Cd-MCM-41 was higher and the BET surface area was lower than those commonly found in our siliceous MCM-41. This is due to the partial pore breakage, as recorded by pore size distribution analysis. The oxygen chemisorption results shows that the dispersion of cadmium is quite high, and decreased after loading of titania. The XRD patterns of Cd-MCM-41 and 25%TiO₂/Cd-MCM-41 are similar to those of siliceous MCM-41; however, the intensity of the d ₁₀₀ peak is decreased and the unit-cell parameter increased with titania loading. Raman spectra could not detect any peaks, whereas peaks were detected at 144, 397, 518 and 641 cm_-1 with loading of titania, these peaks being associated with the anatase phase of titania. The surface composition and binding energy of the Cd 3d_5/2 peak for Cd-MCM-41 and 25%TiO₂/Cd-MCM-41 was analyzed by XPS and showed considerable infusion of cadmium ions on to the surface upon loading of titania. The Cd/Si surface atomic ratio measured by XPS increases 10 times with loading of titania on Cd-MCM-41, indicating that the two separate surface electronic levels such as Cd-O-Si and Cd-O-Ti were found for 25%TiO₂/Cd-MCM-41. The 25%TiO₂/Cd-MCM-41 showed higher activity than 25%TiO₂/MCM-41 for photocatalytic degradation of formic acid. The activity results are compared with the pure titania based on the transformation per site of Ti.     

光电耦合器4N25非线性与线性应用

根据光电耦合器4N25的传输特性,从它的电路工作状态出发,介绍了非线性与线性应用.     

An n1.618 lower bound on the time to simulate one queue or two pushdown stores by one tape

To simulate two pushdown stores, or one queue, on-line by a one-head tape unit requires Ω(n^1.618) time.