Input-output properties of the Page-Hinkley detector

We consider the stochastic input-output properties of a simple non-linear dynamical system, the so-called Page-Hinkley detector, playing a key role in change detection, and also in queuing theory. We show that for L-mixing inputs with negative expectation the output process of this system is L-mixing. The result is applied to get an upper bound for the false alarm rate. The proof is then adapted to get a similar result for the case of random i.i.d. inputs. Possible extensions and open problems are given in the discussion.     

极值系统的在线辨识与稳态优化控制方法研究

研究一种基于非线性环节直接表示的ＳＩＳＯＨａｍｍｅｒｓｔｅｉｎ模型参数辨识方法，针对非线性环节呈极值特性的情况，研究一种由在线辨识得到的非线性环节的参数估计值进行稳态优化的控制方法。仿真结果验证了该方法的有效性。     

“技术”与“情感”的共存——以图书馆建筑设计为例

通过对新近落成的三个北美图书馆设计理念的分析。该文着重阐述在公共图书馆设计中为平衡技术理性与情感满足的三条路径,以及使建筑适应特定环境所采纳的不同处理方法。     

二苯并[b,f]-1,4-氧杂吖庚分子在银胶体系中的表面增强因子的计算

根据在银胶体系中测得刺激剂二苯并[b,f]-1,4-氧杂吖庚因(CR)的表面增强喇曼散射(SERS)光谱的强度,推算出CR分子的表面增强因子可达6.9×10~5,在此实验条件下,其检出限为5.0×10~(-6)mol/L。     

变频器的控制方式及选型应用

对变频器的常用控制方式进行了比较,分析了各种控制方式的优缺点,为工程技术人员更好选择与使用变频器提供了借鉴和参考。     

On the ‘reaction in chain’ in the thermoelectric conversion of energy through thermocouples: Theoretical implications of the phenomenon

It is shown, experimentally, that in certain initial conditions of temperature, and for certain parameters, a ‘reaction in chain’ may start in a thermocouple, and produce a ‘permanent regime’, through which heat from a single course is converted into electrical energy. It is shown, theoretically, that the phenomenon occurs when compensation of heat losses due to thermal conduction, through Peltier and Thomson heat is realized, so that the efficiency is affected only by the Joule effect, and may attain much higher values than through conventional operation of these thermoelectric devices, conventional peration requiring two heat sources, a hot and a cold one.     

大功率InGaAsP/GaAs量子阱半导体激光器的直流和1/f噪声性质

对大功率InGaAsP/GaAs量子阱(QW)半导体激光器(LD)的直流(DC)特性和小注入下的低频噪声(LFN)特性进行了实验研究.DC检测发现,V-J和I dV/dI-I可以对LD的电流泄漏作出判断.LFN检测发现,小注入下的1/f低频电压噪声幅值Bv(I)∝I<'βv>.理论分析和老化实验均表明,电流指数βv与载流子输运和电流泄漏机制之间有很好的相关性,存在电流泄漏和无辐射复合的器件其|βv|较小,可靠性较差.     

Low Voltage CMOS LC VCO with Switched Self‐Biasing

This paper presents a switched self‐biasing and a tail current‐shaping technique to suppress the 1/f noise from a tail current source in differential cross‐coupled inductance‐capacitance (LC) voltage‐controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 µm CMOS process. The measured phase noise is ‐117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.     

Quasi-analytical study of the energy levels in double quantum wells

In this work we develop an analytical expression to the eigenvalue equation for the double quantum well (DQW), to describe the energy gap between resonant levels. The calculation of the energy gap does not involve the evaluation of the wavefunctions for the DQW nor the transfer or tunneling integrals in contrast to how it is usually done.     

基于单片机PIC16F873的光伏供电系统展示板的设计

在能源需求逐步增大、环境污染持续严重的今天,太阳能的利用已经成为各国争相发展的一个热点,同时,中国政府也一直在加强这一领域科学知识的宣传和普及。为此,设计了一种离线式光伏供电系统展示板,其本身就是一个典型的光伏供电系统,主要包括电源管理、系统控制和系统显示等。文中介绍了展示板系统各个部分的功能和软硬件实现方法。通过太阳辐射量等效为标准太阳辐射强度日照小时数的方法,设计了系统中太阳能电池板和蓄电池容量,最后做出实物。