The comparison of several current references and a design of high precision CMOS current reference

本文介绍并分析了几种典型的电流源结构,并设计了一种具有良好稳定性和高精度的CMOS基准电流源。在高精度的基准电流源电路中使用了带隙电路,使电路获得一个不受电源电压、温度和工艺参数影响的基准电压,然后通过电压—电流转换电路获得稳定的基准电流。HSPICE的仿真结果表明:当温度从-55℃到125℃变化时,电流输出仅变化了0.004。This paper compared several typical current references and designed a CMOS current reference circuit with good stability and high precision. The use of bandgap circuit in the high precision current reference circuit produces a voltage reference which isn't affected by supply voltage, temperature and technology characteristics. The voltage reference is transformed into current reference by voltage to current transformation circuit. The HSPICE simulation results show that the circuit can provide an output current reference with a variation 0.004over a temperature range from -55 to 125℃

A Flux Control System Based on Single Chip

介绍一种以PIC16F876为核心的流量控制系统,通过单片机与计算机通讯,实现远距离的自动控制,控制系统经使用效果良好。文章给出了系统设计原理、单片机程序流程图和硬件电路。This paper presents a flux control system based on the single chip PIC16F876.The system realizes the long distance auto control by the communication between single chip and computer.The result has been proved to be good.The design principle of the system,flow chart of single chip and the related circuits are introduced in detail

LED Color Analysis

主要对蓝光、绿光、白光lEd的色度特性进行分析,首先通过单色仪,分别测得蓝光、绿光、白光lEd的相对光谱功率分布并以色度学理论为基础,计算出光源主波长、色纯度、色温和显色指数.计算结果表明:蓝光lEd和绿光lEd主波长随标准光源的不同变化不大,色纯度比较高,分别在0.64和0.87左右,一般显色指数为-29和-14,显色性很差,不适合用来做照明光源.白光lEd主波长随标准光源的不同变化较大,色纯度相当低,接近0,一般显色指数为82,显色性很好,完全符合照明光源的要求.In order to study the color characteristics of light-emitting diode,the characteristics of blue,green and white LED colors are analyzed.Firstly,the spectral power distribution of blue,green,white LED is respectively measured by using the monochromator,and then on the basis of the theory chroma,the main light source wavelength,color purity,color temperature and color rendering index are calculated.The results show that blue LED and green LED dominant wavelengths change little with different standard light sources,and the color purities are relatively high,at 0.64 and 0.87,respectively,the general color-rendering is very poor for the index of-29 and-14,so these blue and green LED are not suitable to be used as lighting source.White LED dominant wavelength largely change with different standard light sources,and color purity is relatively low,near 0,color rendering is good for the general color-rendering index of 82, so white LED is in full conformance with the lighting requirements

The development and in vitro experiment study of a bio-type root canal filling sealer using calcium phosphate cemen

[中文文摘]目的:以磷酸钙骨水泥为原料制备一种生物型纳米根管封闭剂,并对其理化性质、显影效果及对感染根管优势菌的体外抑菌能力进行研究。方法:根据ISO 6876:2001(E)口腔生物材料标准,测定其流动性、凝固时间和晶粒大小,测定不同显影剂比例的材料的显影效果。采用NCCLs推荐的厌氧菌药物敏感试验,用琼脂稀释法研究其对内氏放线菌、厌氧消化链球菌、牙龈卟啉单胞菌、牙髓卟啉单胞菌和具核梭杆菌的体外抑菌效果。应用染色渗漏法测定20颗离体牙的封闭效果,并与氧化锌丁香油糊剂进行比较。采用SPSS12.0软件包对数据进行t检验。结果:调和后的新型纳米根管封闭剂固化后的终产物为羟基磷灰石,晶粒大小为279nm,具有较好的流动性,可操作时间大于30min,凝固时间为(1.0±0.5)h(可调控)。其显影效果良好。MIC≤0.156～0.312。试验组染色渗漏深度显著小于氧化锌丁香油糊剂组(P<0.01)。结论:制备的材料符合新型纳米根管封闭剂的要求。[英文文摘]PURPOSE: The purpose of this study is to develop a novel root canal filling sealers based on calcium phosphate cement (CPC), and to evaluate its physical-chemical properties and in vitro antibacterial activity on the predominant bacteria infecting root canal. METHODS: The fluidity and the setting time of the sealer were tested according to ISO 6876:2001(E) standards. The crystal size of the final product was determined. Its opacification with different composition were measured. The in vitro antibacterial property of the sealer was tested according to the Antimicrobial Susceptibility Testing of Anaerobes recommended by National Committee for Clinical Laboratory Standards (NCCLs).The involved bacteria included Actinomyces naeslundii(A. naeslundii),Peptostreptococcus anaerobius(P anaerobius), Porphyromonas gingivalis (P. gingivalis), Porphyromonas endodpntalis (P. endodpntalis) and Fusobacterium nucleatum (Fnucleatum).Twenty single - rooted human extracted teeth were selected to evaluate the sealing ability using dye microleakage technology. Dye penetration was measured and the results were statistically analyzed using SPSS12.0 software package. RESULTS: The new root canal filling sealer was primarily composed of hydroxyapatite in 279nm after setting. Its liquidity was suitable, the operating time was over 30 minutes, and the controlled setting time was (1.0±0.5) hours. The opacification was acceptable. MIC≤0.156- 0.312. The dye penetration was significant different between two filling types (P<0.01). CONCLUSIONS: The new root canal filling sealer is an ideal root canal filling sealer.厦门科技局资助厦门科技发展课题(2002-60-5

类泛素蛋白及其中文命名

泛素家族包括泛素及类泛素蛋白,约20种成员蛋白.近年来,泛素家族领域取得了迅猛发展,并已与生物学及医学研究的各个领域相互交叉.泛素家族介导的蛋白质降解和细胞自噬机制的发现分别于2004和2016年获得诺贝尔奖.但是,类泛素蛋白并没有统一规范的中文译名. 2018年4月9日在苏州召开的《泛素家族介导的蛋白质降解和细胞自噬》专著的编委会上,部分作者讨论了类泛素蛋白的中文命名问题,并在随后的\"泛素家族、自噬与疾病\"(Ubiquitinfamily,autophagy anddiseases)苏州会议上提出了类泛素蛋白中文翻译草案,此草案在参加该会议的国内学者及海外华人学者间取得了高度共识.冷泉港亚洲\"泛素家族、自噬与疾病\"苏州会议是由美国冷泉港实验室主办、两年一度、面向全球的英文会议.该会议在海内外华人学者中具有广泛影响,因此,参会华人学者的意见具有一定的代表性.本文介绍了10个类别的类泛素蛋白的中文命名,系统总结了它们的结构特点,并比较了参与各种类泛素化修饰的酶和它们的生物学功能.文章由45名从事该领域研究的专家合作撰写,其中包括中国工程院院士1名,相关学者4名,长江学者3名,国家杰出青年科学基金获得者18名和美国知名高校华人教授4名.他们绝大多数是参加编写即将由科学出版社出版的专著《泛素家族介导的蛋白质降解和细胞自噬》的专家

Design of a Fully Differential CMOS Switched-capacitor Integrator for Temperature Sense IC

设计了一种应用于温度传感芯片的全差分开关电容积分器.在温度传感芯片中,Δ-Σ调制器接收温度传感模块输出电压信号,并将模拟的电压信号转换成对应的数字信号.全差分开关电容积分器是Δ-Σ调制器中最核心的元件,它把接收到的温度传感器模块输出的模拟信号转换为数字信号.在开关电容积分器的实际设计中,存在MOS开关的导通电阻和电荷注入、时钟溃通、采样尖峰等非理想因素.本文对这些非理想因素做了详细的分析,设计了一种全差分的开关电容积分器,可以抵消开关电容中电荷注入和时钟溃通带来的电压误差.同时,本文设计了一种全差分共源共栅放大器,可以很好的满足积分器的要求,从而提高整个系统的性能.A fully differential CMOS switched-capacitor integrator for temperature sense IC is proposed and analyzed.In the temperature sense IC,Δ-ΣA/D modulator receives the voltage signal from the temperature sensor,and transforms the analog signal to digital signal.Fully differential CMOS switched-capacitor integrator is the main part of the Δ-ΣA/D modulator.It can realize to transform the analog signal received from the temperature sensor to digital.In the practical design process,there are some non-ideal elements with switched-capacitor integrator,such as non-zero Ron,charge injection error,sampling spike and clock feed-through,etc.All of these non-ideal elements were analyzed in this paper and a fully differential was then presented,which can reduce the charge injection error of MOS switches,clock feed-through and non-ideal performance of operational amplifier.The realization of fully differential folded-cascode operational amplifier can improve the performance of the integrator by which the high performance of the whole system can be achieved

An Improved Bandgap Voltage Reference with High PSRR

设计了一种具有良好稳定性和高精度的带隙基准电压源电路。通过启动电路和提高电源抑制比电路的加入,使得带隙基准电压具有较高的电源电压抑制比和较小的温度系数。HSPICE仿真结果表明,在电源电压V_(DD)=3．3V时,在-55℃～125℃的温度范围内,电路得到一个温度系数仅为17×10~(-6)/℃,电源抑制比(PSRR)为79dB的带隙基准电压输出。A bandgap voltage reference circuit with good stability and high accuracy is designed in this pa- per.The inclusion of the start up circuit and PSRR enhancement circuit enables it to achieve a low temperature coefficient and high PSRR.The HSPICE simulation results show that the circuit can obtain a stable output volt- age with a PSRR of 79 and a temperature coefficient of 17×10~(-6)/℃over the temperature range from-55 to 125℃when the supply voltage is 3.3 V

Application Research in Production of Vacuum Insulation Panel with Electric Capacity Micro-vacuum Sensor

介绍一种基于电容式微型真空传感器的真空度检测系统。系统利用PIC系列单片机对真空绝热板真空度进行实时测量,试验数据表明精度可达10-2Pa,完全满足测量的要求。The paper introduced a vacuum measurement system,which was based on the capacitance micro-vacuum sensor.This system used PIC series microcontroller unit carried on the real-time measurement to the vacuum degree of the vacuum insulation panel.According to the date of our experiments,the precision of the measure of vacuum d-egree can reach to 10-2 Pa,and it satisfies the measurement perfectly