荧光式光纤温度计

<正> 谈到光纤温度计,往往会联想到光纤红外线放射温度计。它是将物质表面放射出的红外线,通过光纤导线使热电堆和半导体元件受光,然后,再换算成温度的非接触式温度计。而本文将介绍的光纤温度计与红外放射温度计相比,其结构正相反,是光源装在测量器主体内部,通过光纤缆线将光照射到装在纤维缆线前端的感温部分,测返回光强度减     

消耗型光纤辐射温度计的新动向

在指出测量熔融金属温度的重要性及采用消耗型热电偶测量铁液、钢水温度存在问题的基础上，重点介绍了消耗型光纤辐射温度计的工作原理、结构及其优点，文末还介绍了消耗型光纤辐射温度计在连铸及高炉的应用情况。     

辐射温度计内调焦系统象方孔径角变化规律

探讨了辐射温度计内调焦系统象方孔径角的变化规律,并以WDH-Ⅲ型小目标光电温度计为例,介绍了该光学系统的应用结果:温度在测量距离从0.5m变化到2.0m的情况下,仪表示值误差为测量值的0.1%。     

一种基于紫外激发荧光寿命测量的光纤温度计

描述了一种基于紫外激发荧光寿命测量的荧光光纤温度计的原理，并对实现过程中遇到的诸如光源与光纤的耦合，光纤探头结构，光电转换电路设计及小信号放大电路噪声抑制等问题进行分析和讨论。     

压力式温度计应用实例

文章经过比较提出了在工程设计中如何应用压力式温度计。     

一种数字温度计的设计方法

介绍一种由热敏电阻和ＥＰＲＯＭ构成的数字温度计的设计方法，这种温度结构简单，使用方便，具有广泛的应用前景。     

液晶温度计的色电转换技术及其应用

提出了利用光纤实现液晶温度计色电转换的技术方法，讨论系统设计并分析了实验结果。简要介绍了基在生物医学研究（血气无创测量）方面的应用。     

基于Pt1000铂电阻的高精度手持温度计研制

针对石油化工行业，尤其是油品的存储和交接过程中，精确测量温度的需求，论述了一种高精度手持式温度计的设计。该设计方案的感温元件使用Pt1000铂电阻和自主研发的嵌入式测量系统。详细讲解了温度计的测量原理和软硬件的设计方案，并给出了一种温度计环温补偿的软件算法。     

辐射温度计光学系统的设计

本文讨论了辐射温度计的视场和温度分辨率与光学系统的两个参数f'和F值的关系.对于非调焦系统,光学系统参数主要由视场决定;温度分辨率由仪表放大器的灵敏度决定.对于调焦系统,光学系统参数可由视场和温度分辨率共同决定.文中给出了辐射温度计光学系统设计的一般方法.     

锗比色温度计及其在热处理炉温度控制中的应用

本文描述了一种采用锗光电二极管做探测器,组合棱镜分光光学的新型比色温度计的设计。温度计使用中温黑体炉标定,并最终应用于空心铜导线生产线热处理炉的温度监控。     

Hydrodynamic focusing with a microlithographic manifold: controlling the vertical position of a focused sample

A microfluidic manifold has been designed, fabricated, and tested that hydrodynamically focuses a sample into the center of a microchannel and provides control over the vertical position of the sample via the flow-rates of the focusing fluids. To characterize the focusing action, a mixing experiment was performed in which the sample fluid and focusing fluid contained different fluorescent dyes. By sweeping the ratio of the rate of the top focusing fluid to the rate of the bottom focusing fluid, the sample was positioned first near the top of the microchannel and then translated downward in steps to the bottom of the microchannel. Images were obtained with confocal microscopy, and the presumptive concentration distributions were computed using multiphysics software. The simulations were shown by direct visual comparison with the experimental images to accurately predict the distributions of fluids in our device. In order to quantitatively compare the two data sets, the images and simulations were analyzed using a simple center-of-mass measurement, and according to this measurement, the simulations accurately predicted the vertical position the focused sample.     

Three-dimensional hydrodynamic flow focusing of dye,particles and cells in a microfluidic device by employing two bends of opposite curvature

This work relates to three-dimensional (3D) hydrodynamic flow focusing, wherein sample is encapsulated by sheath fluid in all the directions, making it a preferred method for particle focusing. Given the complex phenomenon involved in achieving 3D hydrodynamic focusing, we have been able to demonstrate a relatively simple microdevice for achieving this objective. In this work, a novel approach for 3D focusing utilizing two bends of opposite curvature in microchannel is proposed and demonstrated through experiments and numerical simulations. The proposed microdevice is fabricated on a single layer of polydimethylsiloxane and a single sheath inlet is used, thereby simplifying the 3D focusing mechanism and reducing the requirements of cost enhancing accessories. The mechanism underlying particle focusing is examined in detail. This microdevice provides several distinct advantages over other designs mentioned in the literature.     

Parametric study of acoustic focusing of particles in a micro-channel in the perspective to improve micro-PIV measurements

In this study, we propose a new technique to bring most of the particles in a horizontal plane at mid-height of a micro-channel in order to improve the quality of the micro-PIV measurements. The basic principle is to create a stationary acoustic wave along the channel height so that the resulting acoustic force moves the particles toward the pressure node. A parametric study has been carried out without mean flow to characterize the motion of the particles toward the nodal-plane. We found that focusing speed grows with the acoustic pressure amplitude, with the concentration of particles in the suspension and with the particles diameter. We also led a preliminary investigation of acoustic focusing together with a mean stationary flow. We still observed an important focusing of particles for low freestream velocities. Nevertheless, acoustic focusing is inefficient beyond a given critical freestream velocity U ₀ for a given set of acoustic parameters and a given type of particles. It was also shown that other phenomena, like clumps formation, can be observed without mean flow if the acoustic focusing lasts long enough.     

Improving particle detection sensitivity of a microfluidic resistive pulse sensor by a novel electrokinetic flow focusing method

A novel and simple method of improving the particle detection sensitivity of a microfluidic resistive pulse sensor was presented in this paper. This novel electrokinetic flow focusing method utilizes a focusing solution (with high resistivity) flowing from the upstream focusing channel to the downstream focusing channel. The focusing solution in the sensing gate works like a virtual insulation wall that greatly narrows the gate and thus improves the detection sensitivity. An equation was derived to relate the magnitude of the output signal to the resistivity and the width of the focusing solution. The width of the focused particle solution under different voltages was numerically predicted. The results show that the magnitude of output signal increases with the decrease in the width of the focused particle stream. More importantly, the detection sensitivity can be improved by decreasing the space occupied by the focusing solution in the upstream and downstream channels as much as possible. Detection of 1 μm particle with a sensing gate of 30 × 40 × 10 μm (width × length × height) was successfully achieved. The proposed method is simple and advantageous in detecting smaller particles without fabricating a small sensing gate.     

Can you make a computer understand and produce art?

Although artificial intelligence techniques have been successfully applied to reproduce many rational features of human behaviour, a great barrier has been encountered in simulating human activities where intuition and emotion are involved. Art making and viewing are processes where typically rational and mechanical aspects interact with aesthetic and cognitive criteria. Can you make a computer understand and autonomously produce art? The main purpose of this paper is to present the most relevant approaches in the study of art perception and creation via computer, focusing on the results achieved in artistic computer graphics.     

Edge focusing

Edge detection in a gray-scale image at a fine resolution typically yields noise and unnecessary detail, whereas edge detection at a coarse resolution distorts edge contours. We show that ``edge focusing', i.e., a coarse-to-fine tracking in a continuous manner, combines high positional accuracy with good noise-reduction. This is of vital interest in several applications. Junctions of different kinds are in this way restored with high precision, which is a basic requirement when performing (projective) geometric analysis of an image for the purpose of restoring the three-dimensional scene. Segmentation of a scene using geometric clues like parallelism, etc., is also facilitated by the algorithm, since unnecessary detail has been filtered away. There are indications that an extension of the focusing algorithm can classify edges, to some extent, into the categories diffuse and nondiffuse (for example diffuse illumination edges). The edge focusing algorithm contains two parameters, namely the coarseness of the resolution in the blurred image from where we start the focusing procedure, and a threshold on the gradient magnitude at this coarse level. The latter parameter seems less critical for the behavior of the algorithm and is not present in the focusing part, i.e., at finer resolutions. The step length of the scale parameter in the focusing scheme has been chosen so that edge elements do not move more than one pixel per focusing step.     

Multicultural Crisis Communication: Towards a Social Constructionist Perspective

Crisis communication is a field dominated by case studies and is lacking of systematic knowledge and theoretical framework analysis. Functionalist and objectivist perspectives have dominated the field even though there are exceptions. This may be one reason why multicultural approaches to crisis communication, increasingly relevant in contemporary society, are very few and undeveloped. The aim in the article is to give a critical analysis of research that has been done on crisis communication as well as intercultural public relations and develop a different theoretical framework. We propose the use of ethnicity, focusing collective cultural identity as dynamic, relational and situational in crisis theory and practice. Ethnic differences seem to escalate during crises. Media use and access are also discussed. A Swedish survey shows, among other things, that people with a foreign background read mainstream newspapers more seldom than average Swedes, but that the access to Internet and mobile phones is very high. Based on a social constructionist epistemology, the article ends with four proposals for future research and practice in multicultural crisis communication: (1) audience‐orientation – focusing sense‐making, (2) a proactive and interactive approach – focusing dialogue, (3) a community‐focused approach – focusing a long‐range pre‐crisis perspective and, (4) an ethnicity‐approach towards intercultural communication.     

桩柱周期分布的平板中SH波的传播特性分析及其在聚焦透镜设计中的应用研究

本文首先建立求解水平剪切波(即SH波)在桩柱周期分布的板中传播的理论模型,计算其带隙结构,并与有限元仿真的结果进行对比,验证该理论模型的准确性.在此基础上,应用此模型研究桩柱高度对最低阶水平剪切波(即SH0)的影响,发现随着桩柱高度的增加,SH0的相速度降低.基于桩柱高度与相速度的敏感特性,设计了一款可实现SH0聚焦的透镜,并进行相关的仿真分析,研究该透镜的适用范围和聚焦效果.研究结果表明,该透镜聚焦位置准确,聚焦能量高,且在不改变结构的情况下在一定频率范围内均可实现聚焦功能,从而为能量收集、超声医学、无损检测、吸声降噪等应用提供新的思路.     

Issues and approaches of automatic focusing algorithms for intelligent robot eye-in-hand system

The new, fast, automatic focusing algorithms, namely Energy Maximization and Histogram Variance Maximization, for computer vision systems have been presented in this article. These two focusing algorithms have greatly reduced the arithmetical operations needed to perform an automatic focusing operation. Experimental evaluations and comparisons to previously developed algorithms have been performed and the results presented. The improved performance in accuracy and speed of our new algorithms will certainly benefit applications such as distance measurement, target tracking, and scene analysis by the use of computer vision techniques.