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measurement techniques for aspheric surface parameters

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Light(Advanced Manufacturing) 2023年第3期4卷 292-310页

作者： Qun Hao Yiming Liu Yao Hu Xin Tao Beijing Key Laboratory for Precision Optoelectronic measurement Instrument and Technology School of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China

Aspheric surfaces are widely used in advanced optical *** the aspheric surface parameters(ASPs)with high accuracy is vital for manufacturing and aligning optical aspheric *** paper provides a review of various techniques for measuring ASPs and discusses the advantages/disadvantages of these *** aim of this review is to contribute to advancements in the fabrication and testing of aspheric optical elements and their practical applications in diverse fields.

关键词： measurement technique Aspheric surface Parameter

THE ESTIMATE AND measurement OF LONGITUDINAL WAVE INTENSITY

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Acta Mechanica Sinica 1996年第3期12卷 251-262页

作者：明瑞森 Department of Architecture Zhejiang University Hangzhou 310027 China

Quasi-longitudinal waves are one type of structural waves, which are important at high frequencies. This paper studies the estimate theory and measurement technique of quasi-longitudinal waves, analyzes the bias error due to the effect of bending waves. In a two-dimensional quasi-longitudinal wave held, the intensity vector is the sum of the effective intensity vector and the intensity variation vector. Its axial component is proportional to two imaginary parts of cross spectral densities and in the measurement, it is measured by a pair of two-transducer arrays. In a one-dimensional quasi-longitudinal wave field, the intensity variation is zero, the intensity is proportional to only one imaginary part of a cross spectral density and it can be measured using a two-transducer array. If bending and quasi-longitudinal waves coexist and the contribution from bending waves cannot be eliminated or reduced to a certain extent, the measured quasi-longitudinal wave intensity will contain a large error. The results measured on the three-beam structure show that quasi-longitudinal wave intensity can be accurately measured using the intensity technique when bending waves are negligible in comparison with quasi-longitudinal waves.

关键词： quasi-longitudinal wave intensity power flow bias error measurement technique

On the Estimation of the Functional Size of Software from Requirements Specifications

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Journal of Computer Science & Technology 2007年第3期22卷 358-370页

作者： Nelly Condori-Fernández Silvia Abrahao Oscar Pastor Department of Information Systems and Computation Valencia University of TechnologyCamino de Vera s/n46020 ValenciaSpain

This paper introduces a measurement procedure, called RmFFP, which describes a set of operations for modelling and estimating the size of object-oriented software systems from high-level specifications using the OO-Method Requirement Model. OO-Method is an automatic software production method. The contribution of this work is to systematically define a set of rules that allows estimating the functional size at an early stage of the software production process, in accordance with COSMIC-FFP. To do this, we describe the design, the application, and the analysis of the proposed measurement procedure following the steps of a process model for software measurement. We also report initial results on the evaluation of RmFFP in terms of its reproducibility.

关键词： requirement specification product metrics measurement technique

Hydrodynamics research of wastewater treatment bioreactors

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Journal of Harbin Institute of Technology(New Series) 2009年第3期16卷 309-317页

作者：任南琪张冰周雪飞 School of Municipal and Environmental Engineering Harbin Institute of Technology State Key Laboratory of Pollution Control and Resource Reuse Research Tongji University

To optimize the design and improve the performance of wastewater treatment bioreactors,the review concerning the hydrodynamics explored by theoretical equations,process experiments,modeling of the hydrodynamics and flow field measurement is presented. Results of different kinds of experiments show that the hydrodynamic characteristics can affect sludge characteristics,mass transfer and reactor performance significantly. Along with the development of theoretical equations,turbulence models including large eddy simulation models and Reynolds-averaged Navier-Stokes (RANS) models are widely used at present. Standard and modified k-ε models are the most widely used eddy viscosity turbulence models for simulating flows in bioreactors. Numerical simulation of hydrodynamics is proved to be efficient for optimizing design and operation. The development of measurement techniques with high accuracy and low intrusion enables the flow filed in the bioreactors to be transparent. Integration of both numerical simulation and experimental measurement can describe the hydrodynamics very well.

关键词： wastewater treatment bioreactor hydrodynamics simulation measurement technique

measurement of Cavity Loss and Quasi-Fermi-Level Separation for Fabry-Pérot Semiconductor Lasers

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Journal of Semiconductors 2003年第8期24卷 789-793页

作者：韩春林刘瑞喜国伟华于丽娟黄永箴兰州大学物理科学与技术学院兰州730000 中国科学院半导体研究所北京100083

A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor *** the amplified spontaneous emission (ASE) spectrum,the gain spectrum and single pass ASE obtained by the Cassidy method are applied in the fitting *** a 1550nm quantum well InGaAsP ridge waveguide laser,the cavity loss of about ～24cm -1 is obtained.

关键词： semiconductor lasers measurement technique cavity loss

Traveling wave tube measurements for low-frequency properties of underwater acoustic materials

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Chinese Journal of Acoustics 2007年第4期26卷 301-312页

作者： LI Shui LUO Maqi FAN Jinliang SHEN Jianxing Hangzhou applied acoustics research institute Hangzhou Fuyang 311400

A traveling wave tube measurement technique for measurmg acoustic properties of underwater acoustic materials was developed. Water temperature and pressure environments of the ocean can be simulated in a water-filled tube, and the acoustic parameters of samples of underwater acoustic materials are measured in the range of low-frequency. A tested sample is located at central position of the tube. A pair of projectors is separately located at both ends of the tube. Using an active anechoic technique, the sound wave transmitting the tested sample is hardly reflected by the surface of secondary transducer. So the traveling sound field is built up in the tube. By separately calculating the transfer functions of every pair of double hydrophones in the sound fields from the both sides of the sample, its reflection coefficients and transmission coefficients are obtained. In the measurement system, the inside diameter of the tube is 0208 mm, the working frequency range is from 100 to 4000 Hz, the maximum pressure is 5 MPa. The reflection coefficients and transmission coefficients of a water layer and a stainless steel layer samples are measured actually and calculated theoretically. The results show that the measured values are in good agreement with the values calculated, and the measurement uncertainty is not greater than 1.5 dB.

关键词： transmission coefficients reflection coefficients temperature and pressure measurement technique traveling wave tube transfer functions measurement system stainless steel sound fields range of

Comparative studies in method for stratigraphical structure measurement of ice cores: Identification of cloudy bands

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Chinese Journal of Polar Science 2003年第1期14卷 73-80页

作者： MorimasaTakata HitoshiShoji AtsushiMiyamoto KimikoShimohara NationalInstituteofPolarResearch Kaga1-9-10Itabashi-kuTokyo173-8515Japan KitamiInstituteofTechnology Koencho165KitamiHokkaido090-8507Japan InstituteofLowTemperatureScience HokkaidoUniversityN19WSKita-kuSapporoHokkaido060-0819Japan

Cloudy bands are typical stratigraphic structure in deep ice core. Detailed recording of cloudy bands is important for dating of ice core since pair of series cloudy band and clear layer is corresponds to annual layer and it sometimes corresponds to volcanic ash layer. We developed two type scanners, transmitted light method and laser tomograph method for the stratigraphic study. measurements were carried out for NGRIP deep ice core, which containing many cloudy bands, using the two type scanners and digital camera. We discussed about the possibility of identification of cloudy bands by each method and about advantage and disadvantage of measurements and their results.

关键词： Ice core cloudy band physical structure laser tomograph measurement technique