采用AT89c52的乱序键盘设计

The password keyboard as a kind of input device that is essential to bank and other financial departments,it must have high credibility,safety,and the function of keeping secret.Disorder keyboard is a developed kind on the basis of the traditional password keyboard,which increased some new functions and characteristics,for example,there is LED on the surface of the keys,and the numbers displayed on the keys are random,also a certain angle of view is restricted.Outside of a certain angle,the number LED displayed on the keyboard is impossible to be seen.Even other people can see the keys that the customer pressed,but because when the customer finished inputting the password,the key numbers will be re-arranged again,so,the customer unnecessarily worried about that other people would take his password.     

Optimal predictor for a singular random process

An optimal predictor is developed for a singular random process generated by a known system driven by a white noise sequence. The properties of the predictor are compared with those of the optimal predictor for a nonsingular random process.     

Hyperparameter estimation for satellite image restoration using a MCMC maximum-likelihood method

The satellite image deconvolution problem is ill-posed and must be regularized. Herein, we use an edge-preserving regularization model using a ? function, involving two hyperparameters. Our goal is to estimate the optimal parameters in order to automatically reconstruct images. We propose to use the maximum-likelihood estimator (MLE), applied to the observed image. We need sampling from prior and posterior distributions. Since the convolution prevents use of standard samplers, we have developed a modified Geman-Yang algorithm, using an auxiliary variable and a cosine transform. We present a Markov chain Monte Carlo maximum-likelihood (MCMCML) technique which is able to simultaneously achieve the estimation and the reconstruction.     

DRYING OF GRANULAR PARTICLES IN A MULTISTAGE INCLINED FLUIDIZED BED WITH MECHANICAL VIBRATION

A mathematical model for the drying rate of granular particles in a multistage inclined fluidized bed(IFB) is presented from the standpoint of simultaneous heat and mass transfer, with taking the effect of mechanical vibration added vertically into consideration.

Steady-state distributions for the temperatures and concentrations of the particles and the heating gas, and for the moisture content of the particles are numerically calculated based on the present model. The calculated results show fairly good agreement with the experimental data, which were obtained from the drying experiments of brick particles in a three-stage IFB using comparatively low temperature air(40-60°C) as the heating gas.

It has been found within the range of the experimental conditions employed that, the mechanical vibration added vertically enhances the over-all drying rate of the particles and its effect can be considered equivalent to an increase in the air velocity.     

核电厂管系振动鉴定

本文介绍了核电厂管道振动鉴定概况,讨论了目前使用的管系振动的鉴定方法,给出了鉴定准则。     

100m高烟囱拆除爆破冲击振动测试与分析

在新乡电厂百米钢筋混凝土烟囱爆破拆除工程中,布置了不同方向的两条测线共9个测点,量测了爆破和烟囱倒塌触地引起的地面质点振速和主振频率。从实测数据的分析认识到:烟囱顶部落地产生的冲击力最大,线状震源正前方测点的振速比其侧向测点的振速要大;烟囱倒塌触地产生的振动是各段筒体所产生的振动的叠加,它与各分段体的质量、位置高度、材质强度等因素有关;高大建(构)筑物落地冲击地振动的频率一般比爆破引起的地振动的频率要低;铺设缓冲材料、分段爆破等措施可减小触地冲击引起的地面振动强度。此外,利用实测数据进行拟合,得出了适用于描述本工程烟囱倒塌触地冲击地振动衰减规律的经验公式。     

应用频率-初速法测试推算单桩承载力须解决的几个关键问题

本文对当前频率 -初速法应用中存在的一些问题阐述了作者的看法并着重探讨桩振初速度V0的计算方法、W0 的正确单位、如何使桩 -土体系明显震动、怎样从激振曲线中突出及分离出桩振曲线 ,从而获得正确的桩振频率f0 和首波峰 -峰值Ad、动静对比系数 βv 的选取     

后桥壳的可靠性优化设计

该文讨论了后桥壳的可靠性优化设计问题.在基本随机变量的概率特性已知的情况下,应用随机摄动法和约束随机方向法对后桥壳进行可靠性优化设计,并编制了实用的计算机程序,可以迅速准确地得到后桥壳的可靠性设计参数.     

带有集中质量的分布质量弹性转动横振精确解

求得了带有集中质量的分布质量弹性转轴系统横向自由振动的频率方程和振型函数的精确解析表达式，及其与不转动轴系统自由振动的频率方程和振型函数及转动角速度之间的精确解析关系     

Spreading Codes Generator for Wireless CDMA Networks

The prime characteristic of spread spectrum modulated signals is that their bandwidth is greater than the information rate. In this way a redundancy is introduced that allows the severe levels of inteference inherent in the transmission of digital information over radio and satellite links to be overcome. Current spread spectrum applications are primarily in military communications; nevertheless, there is growing interest in this technique for third generation mobile radio networks (UMTS, FPLTS, etc.) with open discussion regarding the practicality of using a multiple access system based on spread spectrum techniques (CDMA). However, in order to support as many users in the same bandwidth as other multiple access techniques such as TDMA or FDMA, it is important how to generate large families of sequences that present low cross-correlation. The aim of this paper is to describe a spreading codes generator that can produce a large number of PN sequences with good properties of auto- and cross-correlation. Moreover, the codes generated shows high unpredictability and good statistical behaviour. This also allows the implementation of some features that are common on military networks such as message privacy (increasingly important in commercial networks) without additional cost. The structure presented shows itself to be advantageous for high speed generation of codes at a low cost, low power consumption (allowing longer life for batteries), small size and simplicity of implementation, essential ingredients for commercial equipment. Another attractive feature is its structural parallelism, useful in VLSI implementations. All of these features render it potentially suitable for the implementation of channel bandwidth sharing systems in future wireless personal communications networks.