An immersible fiber-optic fluorometer

An immersible fiber-optic fluorometer is used to investigate the sea water composition and the phytoplankton content at various depths. Owing to the design features of its immersed part, the fluorometer is capable of making continuous measurements at a widely varying water illuminance. A procedure for calculating the basic structural components of the immersed module is described. Results of laboratory testing of the fluorometer are presented.     

A polarimetric interferential radiometer

A polarimetric interferential radiometer operating in the L band and the procedure for measuring a full set of Stokes polarization parameters are described. It is shown that the interference principle of operation of the measuring system is intended to obtain the Stokes-polarization and polarization-ellipse parameters. Some polarization parameters preliminarily measured in a 1410-to 1420-MHz frequency band for seawater radiation are given.     

Mobile laser meter of hydrosphere pressure variations

A device for measuring hydrosphere pressure variations at depths of down to 1000 m in the frequency range of 0–1000 Hz with an accuracy of 10–30 mPa is described.     

Laser NIR lifetime spectrometer with nanosecond time resolution

A laser lifetime spectrometer (fluorometer) for recording the luminescence kinetics in the range 950–1400 nm with a time resolution of 1 ns is described. The performance capabilities of the facility are demonstrated by an example of studying the near-IR luminescence of molecular singlet oxygen ¹O₂. The fluorometer allows measurements of quenched luminescence of ¹O₂ with a quantum yield of up to 6 × 10⁻⁹.     

Experimental study on free and submerged multi-jets

The flow characteristics of the hydraulic jump due to parallel jets are different from the classical jump emerging from a single gate. Due to the highly complex flow field at the downstream pool, deciding about the tailwater measuring location is a challenging issue affecting the flow measuring accuracy. Experiments are conducted herein, on different parallel jets’ configurations for both free and submerged flow conditions. To quantify the flow uniformity, for any downstream cross section, the associated momentum correction factors, β₂, were estimated for the free-flow condition. It is found that β₂-values depend significantly on the measuring location, and consequently the available conjugated depths relationship results in poor estimation when measuring location moves downstream. Employing Buckingham analysis, a general formula is proposed to calculate the momentum correction factors associated with the free hydraulic jump at different downstream measuring locations. The experimental results of this study indicated that such a formula enhances distinguishing between free and submerged flow conditions of the gates installed in parallel. Finally, a dimensionless stage-discharge formula is presented to predict the submerged flow rate through parallel gates of different gate openings and widths.     

A spectrometer for seeking exotic states of pionic atoms of xenon

The parameters of a spectrometer for searching for deeply bound pionic states of xenon are presented. The main component of the spectrometer is a multilayer semiconductor telescope based on high-purity germanium detectors. A technique for calibrating the spectrometer and measuring its energy resolution using reactions p(d, ³He)π⁰ and ¹⁴N(d, ³He)¹³C is described. The energy resolution of the setup is shown to be 0.85 MeV for ³He ions with an energy of ～360 MeV.     

Reliability of roughness measurements using contact stylus instruments with particular reference to results of recent research at the Physikalisch-Technische bundesanstalt

Even today international comparison measurements of surface roughness show differences of 40% and more, as they did more than 10 years ago. However, within the framework of the Deutscher Kalibrierdienst, differences occurring in comparison measurements do not exceed 5%. At the end of 1982, a project of the European Communities was started for the purpose of also carrying out comparison measurements yielding small differences. The prerequisites are the following: clearly defined surface roughness parameters including details of the measurement conditions required and calibration and testing of the contact stylus instruments before the comparison measurements are made.In recent years the contacting process, the interaction between stylus and surface, has been the subject of very thorough investigations at the Physikalisch-Technische Bundesanstalt. Elastic and plastic deformations of the surface were examined. The parameters of influence are the geometry of the stylus tip and of the surface under examination, the properties of the materials, the static and dynamic measuring forces and the rate of feed. Calculation methods for optimizing these parameters are stated in order to keep the resulting measurement errors as small as possible. A new contactless measuring method is described which is based on the evaluation of scanning electron microscopy stereo pairs. An error analysis makes precision measurements possible which up to now could not be carried out at all. Examples examined have shown that sometimes, particularly on finely ground surfaces, measurements with contact stylus instruments on surfaces with R_z values below 1 μm can be very significantly in error.     

Scanning Electrode System for Surface Studies

Abstract

The construction of a scanning electrode system is described. The system is designed to measure chemical and electrical parameters above surfaces. It was tested with scanning reference and scanning pH electrodes on a steel coupon which contains a weld, several artificial corrosion pits of different depths and diameters, and an artificial crack of varying depth. The apparatus is computer controlled; the program for control of the apparatus is provided. A stationary electrode is utilized with a moved examined surface (a coupon). The apparatus is capable of determining surface dimensions of pits, but not pit depths. The artificial pits and crack were shown to be anodic locations. The solution above the pits and crack was more acidic than the solution above the remainder of the coupon.     

The Mollyusk-07 self-contained vertical acoustic-hydrophysical measuring system

The Mollyusk-07 self-contained vertical acoustic-hydrophysical measuring system has been designed for experimental studies of the mode structure of internal waves and low-frequency sounds that propagate in shelf zones of seas and oceans. The Mollyusk-07 is capable of synchronously measuring the variations in the sound pressure over a 10- to 5000-Hz frequency band and water temperatures with a resolution of up to 0.006°C at eight depths, as well as the absolute values of the flow velocity at one of the depths; it also monitors the positions of the upper and middle hydrophones along the depth. The Mollyusk-07 is intended to be installed at depths of up to 100 m beneath the sea surface by the anchor separated by an acoustic release. The program control over the measurement and data acquisition modes is realized in the system. The self-sufficiency of operation in the sea is at least 7 days. In 2007, the Mollyusk-07 passed tests on the shelves of the seas of Japan and Okhotsk.     

Damage identification in composite materials using ultrasonic based Lamb wave method

The paper presents an ultrasonic based Lamb waves propagation method for identifying and measuring the damage location in a material for SHM. The present work determines the experimental and analytical effects of various parameters on the sensitivity of damage detection and a methodology is proposed for estimating and measuring the location of damage in the test specimens. An experimental setup is used for generating A_o Lamb waves by calibrating ultrasonic pulse generation for optimal value of the parameters. The experiment is performed on two carbon fiber reinforced plastic bars in both undamaged and damaged state, where the two damaged states are (1) having a cut partway through the bar, perpendicular to the long axis of the bar and (2) having a circular hole. The Lamb wave propagation parameters are calibrated using the ultrasonic pulse generator test setup and the method was compared with direct measured values of ultrasonic instrument.     

Computer vision algorithms for measurement and inspection of spur gears

Precision measurement of gears plays a vital role in gear measurement and inspection. The current methods of gear measurement are either time consuming or expensive. In addition, no single measurement method is available and capable of accurately measuring all gear parameters while significantly reducing the measurement time. The aim of this paper is to utilize the computer vision technology to develop a non-contact and rapid measurement system capable of measuring and inspecting most of spur gear parameters with an appropriate accuracy. A vision system has been established and used to capture images for gears to be measured or inspected. A software (named GearVision) has been especially developed in-house using Microsoft Visual C++ to analyze the captured images and to perform the measurement and inspection processes. The introduced vision system has been calibrated for metric units then it was verified by measuring two sample gears and comparing the calculated parameters with the actual values of gear parameters. The maximum differences between the calculated parameters and the design values were ±0.101 mm for a spur gear with 156 mm outside diameter. For small gears, higher accuracy could be obtained and as well as small difference.     

霍尔器件参数测试系统

提出了一种基于微控制器的霍尔器件参数测试系统设计方案.描述了总体设计方案,并详细介绍了硬件部分的可调电压源和数据采集部分.给出了系统软件设计思想及部分参数的测试结果.该霍尔器件参数测试系统可以快速准确地测量霍尔器件的各项电参数和磁参数,并且具有测试和筛选功能,操作界面友好,使用方便.     

A time-of-flight mass spectrometer for monitoring the inhalational anesthesia concentration in the real-time mode

The use of a medical mass spectrometer for measuring the concentration of the gas mixture components in the breathing circuit of an inhalational anesthesia machine in the real-time mode is described. The resolution of the mass spectrometer is M/ΔM = 200, and the detection threshold in terms of the partial pressure of the analyzed gases is 2 × 10^?12 mbar. The mass spectrometer is capable of measuring the volumetric content of CO₂, O₂, and inhalational anesthetic sevoflurane. The respiratory coefficient (CO₂/O₂) was measured during anesthesia to estimate the patient’s stress reaction to a surgical injury.     

特纳10-AU现场荧光仪吸收光谱测定套件的研发及应用

针对天然水体中溶解有机物吸收和荧光无法同时测定的问题,对特纳10-AU现场荧光仪进行了改进。通过对仪器样品室的改造,利用反射镜改变光路,设置衰减片和降低光电倍增管电压控制光通量,在不破坏原有仪器结构下实现其吸收光谱测定功能。改进后的仪器测定重铬酸钾和高锰酸钾水溶液的灵敏度较Cary100紫外可见分光光度计分别高约1倍和0．5倍,相对标准偏差分别为3．93％、2．12％（n=7）。实现了腐殖酸水溶液的吸收和荧光的同时测定,检出限分别为0．306mg／L和0．0104mg／L。实验证明改进后的10-AU现场荧光仪可用于水体中溶解有机物吸收光谱的测定,操作简便,测定结果可靠。     

A set of measuring microwave resonators

An universal set of broadband high-Q measuring resonators operating in a frequency band of 0.6–180 GHz is described. The resonators may be used for physical investigations, measuring parameters of different media, and in spectroscopy, holography, radio-astronomy, communication engineering, and physical electronics. The microwave resonators with a mechanical frequency tuning range of 1/2 octave and higher and a loaded Q-factor of no less than 10⁵ are created, and there is a possibility of electronic frequency adjustments in them.     

轻武器光学瞄具的视差参数测试

在对传统的视差测量方法进行充分研究的基础上,提出了基于自动调焦技术的轻武器光学瞄具的视差参数测试方法。介绍了自动调焦技术的工作原理及其系统组成框图;根据轻武器瞄具性能指标的具体要求,结合自动调焦技术设计了一套轻武器瞄具的视差参数测试系统,并介绍了被测瞄具放入该测试系统前后的自动调焦过程;最终通过求取视度之差得到视差。根据轻武器瞄具光学系统的实际测试要求进行了5次测试实验,并对这5次实验数据进行了分析。结果表明:视差测试精度为0.0296m-1,达到了轻武器光学瞄具技术指标0.1m-1的要求,保证了测量精度。     

Surface finish prediction models for precision grinding of silicon

Conventional grinding of silicon substrates results in poor surface quality unless they are machined in ductile mode on expensive ultra-precision machine tools. However, precision grinding can be used to generate massive ductile surfaces on silicon so that the polishing time can be reduced immensely and surface quality improved. However, precision grinding has to be planned with reliability in advance and the process has to be performed with high rates of reproducibility. Therefore, this work reports the empirical models developed for surface parameters R _a, R _max, and R _t with precision grinding parameters, depths of cut, feed rates, and spindle speeds using conventional numerical control machine tools with Box–Behnken design. Second-order models are developed for the surface parameters in relation to the grinding parameters. Analysis of variance is used to show the parameters as well as their interactions that influence the roughness models. The models are capable of navigating the design space. Also, the results show large amounts of ductile streaks at depth of cut of 20?μm, feed rate of 6.25?mm/min, and spindle speed of 70,000?rpm with a 43-nm R _a. Optimization experiments by desirability function generate 37-nm R _a, 400-nm R _max, and 880-nm R _t with massive ductile surfaces.     

Cutting force analysis in reaming of ZL102 aluminium cast alloys by PCD reamer

The cutting forces are studied for the reaming of casting aluminium alloy ZL102 (ZAlSi12) using a four-flute PCD reamer on DMG DMU 50 linear five-axis CNC machine. Kistler Dynamometer is used to measure the cutting force (X-, Y- and Z-axes) and torque. Three-coordinate measuring machine is used for measuring cylindricity of machined hole. The cutting force signatures are diagnosed by using Fast Fourier Transform (FFT) algorithm. FFT analysis suggests that fundamental frequency is only determined by cutting speed. The frequency for the thrust signal of cutting force is zero which illustrates that the thrust is constant when cutting speed and cutting feed are fixed. The relationship between the cutting force and cutting parameter are investigated by using FFT filtering. High value of cutting feed and the low cutting speed provide the higher thrust. The optimized machining parameters are provided relative to cutting force (Fx and Fy) and the cylindricity of reamed holes.     

Single Photon Counting With Synchronously Pumped Dye Laser Excitation

ABSTRACT

This article reviews the advances that have been made in the technique of pulse fluorometry with time-correlated single photon counting detection brought about by the introduction of mode-locked synchronously pumped dye laser excitation. High repetition rates and small pulse width permit high data collection rates and excellent time-resolution. A modern pulse fluorometer which allows efficient measurement of fluorescence decay curves as well as automated measurement of time-resolved fluorescence spectra and of fluorescence anisotropy decays is described in detail.