一种新的时变大系统递阶控制求解方法

研究了一种新的大系统求解方法,利用Taylor级数的性质,将大系统时变递阶控制问题 转化为代数方程的求解问题.该方法简单,易于编成计算机程序.算例表明了它的有效性.     

A comparative study on coronary angiography and exercise ECG testing

42 patients with chronic urinary retention caused by BPH were treated by means of Mesh-like tubular stent placing from August 1993 to August 1994. The mesh-like tubular stent was made of nickel titanium alloy in sizes of 2.0 x 1.5 cm, 2.5 x 1.5 cm, 3.0 x 1.5 cm respectively. Under direct vision the stent was placed with the deployment tool. The desirable position of the stent is 0.3-0.5 cm proximal to the internal urethral orifice, 0.5 cm distal to the verumontanum. In 38 patients followed up for 1-6 months, 34 were succesful with an effective rate of 80%. IPSS, PUFR, RUV after 1, 3, 6 months of placement were 8.5 +/- 4.4, 6.8 +/- 3.5, 7.1 +/- 5.2; 12.5 +/- 6.0 ml/s, 14.0 +/- 5.2 ml/s, 14.4 +/- 8.1 ml/s; 43 +/- 11.5 ml, 47.4 +/- 13.3 ml, 44.5 +/- 15.7 ml respectively. Four stents were taken away transurethrally in the unsuccessful cases. The results indicat that there are no serious complications except for shorttime hematuria, fever, and bladder irritation. The success depends chiefly upon exactly meassuring the length of prostatic urethra, selecting the rational size of the stent, and correctly placing the stent.     

双面肖特基势垒型GaAs粒子探测器的电特性研究

研究了有源面积为９ｍｍ２的双面肖特基势垒ＧａＡｓ粒子探测器的电特性。器件工艺简单，结构新颖，反向耐压高于３００Ｖ，反向漏电流密度低（９１ｎＡ／ｍｍ２），该器件能经受能量为１．５ＭｅＶ、剂量为１０００ｋＧｙ的电子照射，电特性正常，是一种抗辐照的粒子探测器。     

锻钢退火炉消烟除尘技术改造

介绍了锡钢集团公司锻压分厂车底式热处理退火炉消烟除尘综合治理改造情况。包括烧嘴重新选型、配置，增设空气预热器及重油加热系统，并将下排烟改为地上排烟。改造的主要目的是消烟除尘，提高产品退火质量，提高炉子装备水平及节省燃油消耗。改造后运行结果基本达到了预定目标。     

TiO_2对ZrO_2－NiCr金属陶瓷烧结特性和相稳定性的影响

本文研究了ＴｉＯ２掺入对ＣａＯ稳定ＺｒＯ２（简称ＣａＳＺ－ＮｉＣｒ）金属陶瓷烧结特性的影响，测定了ＣａＳＺ－ＮｉＣｒ－ＴｉＯ２金属陶瓷烧结样品的密度和显微硬度，结果表明，ＴｉＯ２的掺入能提高ＣａＳＺ－ＮＩＣｒ金属陶瓷的烧结密度和显微硬度，对ＣａＳＺ－ＮｉＣｒ金属陶瓷有助烧结作用．金相观察表明，ＴｉＯ３的掺入改变了ＮｉＣｒ相在金属陶瓷中的形貌，说明了ＮｉＣｒ与ＣａＳＺ的浸润性有一定的改善．ＸＲＤ和ＥＰＭＡ分析结果显示，ＴｉＯ２偏聚在ＮｉＣｒ金属相中，不影响ＣａＳＺ的稳定性．     

微机硬件环境与安全

微机硬件的运行环境和硬件安全是计算机网络信息系统能够正常运行的基础,硬件的运行环境和安全直接影响着网络信息系统的安全。而来自于环境干扰、设备自然损坏、自然灾害等因素给微型计算机带来了安全威胁。本文介绍了微机运行的硬件的环境要求、硬件的安全威胁,并提出了用来实现信息安全的硬件安全技术方法。     

Information analysis of single photon emission computed tomography with count losses

An analysis is presented of the information transfer from emitter-space to detector-space in single photon emission computed tomography (SPECT) systems. The analysis takes into account the fact that count loss side information is generally not available at the detector. Side information corresponds to the number gamma-rays lost deleted due to lack of interaction with the detector data. It is shown that the information transfer depends on the structure of the likelihood function of the emitter locations associated with the detector data. This likelihood function is the average of a set of ideal-detection likelihood functions, each matched to a particular set of possible deleted gamma-ray paths. A lower bound is derived for the information gain due to incorporating the count loss side information at the detector. This is shown to be significant when the mean emission rate is small or when the gamma-ray deletion probability is strongly dependent on emitter location. Numerical evaluations of the mutual information, with and without side information, associated with information-optimal apertures and uniform parallel-hole collimators are presented.     

Data stream classification with novel class detection: a review,comparison and challenges

Knowledge and Information Systems - Developing effective and efficient data stream classifiers is challenging for the machine learning community because of the dynamic nature of data streams. As a...     

基于ZigBee的温室监测系统的低功耗设计

针对传统温室大棚有线监测系统存在施工复杂、线路多和维护难等缺陷,提出了一种基于ZigBee无线传感网络技术的低功耗温室监测系统的设计方案;通过对系统各部分的能耗进行分析,结合实际情况对传感器节点采用低功耗设计策略;硬件设计上采用低功耗射频芯片和智能开关芯片,软件编写上采用事件驱动方法延长节点休眠时间;该系统能够准确采集温室内光照度、空气温湿度、土壤水分和二氧化碳浓度等环境信息,并具有低功耗、低成本和易扩展等特点;测试结果验证了该方案的可行性。     

IEEE 1394b VersaPHY的IP核设计与实现

文章提出了VersaPHY的IP核的实现方案;根据VersaPHY协议,分析了VersaPHY的标签、数据包和寄存器,完成了VersaPHY的IP核设计;在Altera QuartusⅡ开发平台上,结合Verilog HDL语言和其自带的IP CORE实现了VP-Label寻址的数据包(读请求包、读响应包、写请求包、写响应包)的接收和发送;最后借助于QuartusⅡ集成开发环境提供的SignalTapⅡ逻辑分析仪进行验证,结果表明,该系统可以实现不同速度(100Mb/s、200Mb/s、400Mb/s、800Mb/s)的VersaPHY的数据包的传输,工作稳定可靠,满足实际应用需求。