基于模糊控制的恒电位仪在核电站应用

介绍了恒电位仪在核电领域的应用现状,提出了设计基于模糊算法的恒电位仪,给出了模糊算法的隶属函数模型和分布图,并根据该算法研制在国内某核电厂实际应用的恒电位仪,根据现场反馈,新恒电位仪的稳定性和可靠性得以提高。     

电流型电化学传感器恒电位仪电路的研究

电流型电化学传感器在与目标气体发生反应的同时,还会与其他氧化性气体发生反应,影响测量值。针对上述问题,根据恒电位仪工作原理,利用高精度基准电压源、直流负反馈电路及参比电极电路研究了一种恒电位仪电路,为传感器工作电极提供一个恒定电位,提高传感器的选择性。同时对工作电极相对于参比电极的电压与给定电位的关系进行实验,获取了控制电位的性能指标。实验验证了该电路具有给定电位稳定（相列误差不大于0．2％）、控制电位精度高（相对误差不大于0．3％）、易于实现等特点。     

适用于阴极防腐保护的一种新型恒电位仪

提出一种适用于油气集输管线阴极防腐保护恒电位仪的新型功率变换器,对其工作原理作了详细讨论,结合具体应用实例阐述一种简单实用的脉冲频率控制方法,给出了该恒电位仪的有关实验波形和输出外特性曲线.研制结果表明,采用零电流功率开关有利于降低开关损耗和提高变换器的容量与效率.     

智能电子电位仪通过技术鉴定

由南京航空学院506教研室和南京铁路分局东机务段协作研制的智能电子电位仪于1989年12月8日在东机务段通过技术鉴定。南京航空学院科研处处长和南京铁路分局总工程师等出席了会议。该仪器用于进口ND-5型内燃机车电控柜的检测。能对多个测试点电位进行自动测量、     

微机控制自动电位滴定仪的研制——ZDJ—4型自动电位滴定仪的设计和性能

一、ZDJ—4型自动电位滴定仪的特点: 该仪器是多功能的滴定系统,能满足各种类型电位滴定的容量分析要求,除能进行自动滴定、空白滴定和手动滴定外,还具有一般离子计的基本功能,如斜率标定、直读浓度、一次添加和电位测定等。该机由于采用了性能优越的双高阻电位仪和高精度的滴定管,故具有输入阻抗高,电位稳定性好、控制精度高和重现性好等特点。(计算机系统和     

电化学检测中流动式实时HGR显示程序设计

微型计算机已被用于电分析实验过程的控制以及数据的采集与处理。为了监控实验进程,人们往往希望能够实时地将采集到的数据展现在显示器的屏幕上。在线性扫描伏安测定等实验中,电位扫描范围一般是预定的有限值,因而电流随电位(或时间)变化的全貌可在屏幕上完整地显示出来。然而在某些测量中由于持续时间较长,要使电流(或电位)～时间曲线完整地显示在屏幕上便有困难。在研制金属渗氢测量系统时我们通过 Apple     

便携式AChE传感器系统的开发与研究

酶传感器体积小、适合野外分析,在环境污染检测、食品农药残留快速分析中具有重要的应用价值。本文基于酶抑制分析原理,构建了一套便携式AChE酶传感器系统。整个系统由恒电位仪采集数据,通过基于ARM7的系统板控制恒电位仪,采用丝网印刷工艺印制电极。在基于μClinux嵌入式系统应用软件的控制下,实现酶传感器检测农药的功能。整个系统提供了良好的控制界面,实验结果显示对硫磷检测限可低于2×10-9(2ppb)。     

BH-1型便携式旋桨流速仪的研制

介绍了一种新型BH-1型便携式旋桨流速仪,主要由自主研制的流速传感器、手持式主机及微机数据回放处理软件三部分组成.其传感器采用新颖的导流筒和导流罩结构设计,增加了系统的抗干扰能力,有效提高了测量准确性.应用单片机技术实现了数据的实时检测与处理,多路存储以及瞬时测量流量功能.通过静态试验标定,表明该流速仪测量范围(O.04～4)m/s,非线性误差为0.874%.该流速仪结构新颖、使用轻巧方便、稳定可靠,已广泛应用于国家海洋局对陆源人海排污口排污监测和海洋环境管理工作中.     

壁面—射流(WALL—JET)色谱电化学检测器的研制

本文报告了一种色谱电化学检测器的研制及初步应用。检测系统包括TP—801单板计算机、基于D/A转换的极化电压波形发生器、恒电位系统和壁面—射流电化学池(Wall—Jet Electrochemical Cell)。能用于流动体系中各种电化学测量和研究,并与高效液相色谱联用测定了医用维生素C药片和注射剂中抗坏血酸的含量,表明性能良好。     

核电厂棒电源系统停堆功能的接口设计

为解决核电工程项目中因系统接口不明晰而可能造成的安全风险及工程进度延误等问题,以第三代国产化核电堆型CAP1400示范工程为例,着重解决了与棒电源系统实现停堆功能相关的接口问题。简要介绍了核电厂棒电源系统的基本结构和功能需求,给出了CAP1400数字化仪控系统的总体结构,并重点描述了棒电源系统(RDPS)、多样化驱动系统(DAS)、主交流电源系统(ECS)、电厂控制系统(PLS)、地震自动停堆系统(ESS),包括仪控系统的层级分布、接口功能实现原理及设计特点等。总结了第三代核电堆型CAP1400棒电源系统停堆功能的多样性和冗余性等特点。该设计保证了RDPS停堆功能的安全、可靠运行,并为后续核电项目的接口设计及管理提供参考。     

工业过程的一类时变模型的建立与控制方法研究

电渣重熔过程是典型的时变系统。电渣重熔炉冶炼质量高的原因在于过程熔速控制均匀。本文通过现场运行数据采集与仿真分析，详细解析了电渣重熔炉过程中诸多参数之间的相互关系，提出并实现了电渣重熔炉的时变系统模型，并成功的应用于邢台机械轧辊集团铸钢分厂美国康萨克15吨电渣炉技改项目上。通过现场6个月的实际运行，控制效果良好，部分参数甚至优于原控制系统。     

A microfluidic erythrocyte sedimentation rate analyzer using rouleaux formation kinetics

Red blood cell aggregation is an intrinsic property of red blood cells that form reversible stacked structures, also called rouleaux, under low shear rates. Erythrocyte sedimentation rate (ESR), commonly performed in clinics, is an indirect inflammation screener and a prognostic test for diseases. We have recently developed a microfluidic system for rapid measurement of ESR from 40 µl whole blood employing the aggregation dynamics. In this work, we propose the use of an aggregation inducer, dextran polyglucose, for the preparation of multiple blood samples with differing aggregation dynamics. Using these samples, we characterized the performance of the system with three aggregation indices and under varying experimental conditions. Additionally, using the same underlying principle, we improved the system for ESR measurement using both venipuncture and fingerprick whole blood samples depending on the user needs. The results demonstrate that the system performs equally well with both samples, which validates the compatibility of the system for both laboratory and point-of-care applications where venous and capillary blood are the primary samples, respectively. The detailed characterization presented in this study legitimates the feasibility of the system for ultrafast and facile measurement of ESR in clinics and diverse off-laboratory settings.     

A formal characterization of epsilon serializability

Epsilon serializability (ESR) is a generalization of classic serializability (SR). In this paper, we provide a precise characterization of ESR when queries that may view inconsistent data run concurrently with consistent update transactions. Our first goal is to understand the behavior of queries in the presence of conflicts and to show how ESR in fact is a generalization of SR. So, using the ACTA framework, we formally express the intertransaction conflicts that are recognized by ESR and through that define ESR, analogous to the manner in which conflict-based serializability is defined. Secondly, expressions are derived for the amount of inconsistency (in a data item) viewed by a query and its effects on the results of a query. These inconsistencies arise from concurrent updates allowed by ESR. Thirdly, in order to maintain the inconsistencies within bounds associated with each query, the expressions are used to determine the preconditions that operations have to satisfy. The results of a query, and the errors in it, depend on what a query does with the (possibly inconsistent) data viewed by it. One of the important byproducts of this work is the identification of different types of queries which lend themselves to an analysis of the effects of data inconsistency on the results of the query     

Data semantics for improving retrieval performance of digital newsvideo systems

We propose a novel four-step hybrid approach for retrieval and composition of video newscasts based on information contained in different metadata sets. In the first step, we use conventional retrieval techniques to isolate video segments from the data universe using segment metadata. In the second step, retrieved segments are clustered into potential news items using a dynamic technique sensitive to the information contained in the segments. In the third step, we apply a transitive search technique to increase the recall of the retrieval system. In the final step, we increase recall performance by identifying segments possessing creation-time relationships. A quantitative analysis of the performance of the process on a newscast composition shows an increase in recall by 59 percent over the conventional keyword-based search technique used in the first step     

Kriging代理模型在对地观测卫星系统优化中的应用

结构优化是对地观测卫星系统(Earth observation satellite system,EOSS)性能提高的关键,但其覆盖性能难以解析计算.为实现EOSS优化,提出了仿真优化的求解思路:构建Kriging代理模型对仿真数据进行拟合,采用代理模型最优和最大化期望提高相结合的机制选择更新点,并定义单位距离的函数改进对更新点进行过滤;提出了改进广义模式搜索算法求解代理模型,搜索步采用遗传算法和序列二次规划算法实现,筛选步采用不完全动态筛选.最后,通过仿真实例和对比实验验证了本文方法的有效性.     

Integrating relational and object-oriented database systems using a metaclass concept

This paper presents a specific approach of integrating a relational database system into a federated database system. The underlying database integration process consist of three steps: first, the external database systems have to be connected to the integrated database system environment and the external data models have to be mapped into a canonical data model. This step is often called syntactic transformation including structural enrichment and leads to component schemas for each external DBMS. Second, the resulting schemas from the first step are used to construct export schemas which are then integrated into global, individual schemas or views in the third step. In this paper we focus on the first step for relational databases, i.e., the connection of a relational database system and the mapping of the relational model into a canonical data model. We take POSTGRES as the relational database system and the object-oriented federated database system VODAK as the integration platform which provides the open, object-oriented data model as the canonical data model for the integration. We show different variations of mapping the relational model. By exploiting the metaclass concept provided by VML, the modelling language of VODAK, we show how to tailor VML such that the canonical data model meets the requirements of integrating POSTGRES into the global database system VODAK in an efficient way.     

On the Multiple Implementation of Abstract Data Types Within a Computation

A fundamental step in the software design process is the selection of a refinement (implementation) for a data abstraction. This step traditionally involves investigating the expected performance of a system under different refinements of an abstraction and then selecting a single alternative which minimizes some performance cost metric. In this paper we reformulate this design step to allow different refinements of the same data abstraction within a computation. This reformulation reflects the fact that the implementation appropriate for a data abstraction is dependent on the behavior exhibited by the objects of the abstraction. Since this behavior can vary among the objects of a computation, a single refinement is often inappropriate. Accordingly, three frameworks are presented for understanding and representing variations in the behavior of objects and, thus, the potential for multiple implementations. The three frameworks are based upon: 1) a static partitioning of objects into disjoint implementation classes; 2) static partitioning of classes into implementation regions; and 3) dynamic partitioning of classes into implementation regions. These frameworks and analytic tools useful in investigating expected performance under multiple implementations are described in detail.     

电渣重熔炉计算机控制系统设计与实现

电渣重熔炉是电渣重熔过程的典型设备。我国在90年代引进的康萨克电渣炉的控制系统存在一定的不足之处。文章通过分析其控制系统原理及潜在的问题,提出了新的控制系统方案,并成功应用于邢台机械轧辊集团铸钢分厂的电渣炉技改项目上。通过现场6个月的实际运行,控制效果良好,部分参数甚至优于原控制系统,从而说明新的控制方案是可行而有效的。     

Inertially Aided Visual Odometry for Miniature Air Vehicles in GPS-denied Environments

Unmanned miniature air vehicles (MAVs) have recently become a focus of much research, due to their potential utility in a number of information gathering applications. MAVs currently carry inertial sensor packages that allow them to perform basic flight maneuvers reliably in a completely autonomous manner. However, MAV navigation requires knowledge of location that is currently available only through GPS sensors, which depend on an external infrastructure and are thus prone to reliability issues. Vision-based methods such as Visual Odometry (VO) have been developed that are capable of estimating MAV pose purely from vision, and thus have the potential to provide an autonomous alternative to GPS for MAV navigation. Because VO estimates pose by combining relative pose estimates, constraining relative pose error is the key element of any Visual Odometry system. In this paper, we present a system that fuses measurements from an MAV inertial navigation system (INS) with a novel VO framework based on direct image registration. We use the inertial sensors in the measurement step of the Extended Kalman Filter to determine the direction of gravity, and hence provide error-bounded measurements of certain portions of the aircraft pose. Because of the relative nature of VO measurements, we use VO in the EKF prediction step. To allow VO to be used as a prediction, we develop a novel linear approximation to the direct image registration procedure that allows us to propagate the covariance matrix at each time step. We present offline results obtained from our pose estimation system using actual MAV flight data. We show that fusion of VO and INS measurements greatly improves the accuracy of pose estimation and reduces the drift compared to unaided VO during medium-length (tens of seconds) periods of GPS dropout.