一个测面仪的设计方案

一、问题的提出 牛顿曾要他的助手为他测量一下一个灯泡的体积,该助手不愧是位数学家,他拿起灯泡就开始测数。量呀量,牛顿转身时见了,眉头一皱道:“这样做太繁,取点水来倒入量筒,再把灯泡往水中一浸不就知道了吗?”物体可以用排水法得出它的体积,一个不规则的平面是否也可用一个装置、不用测量而直接读出其面积呢?

Determination of efficient superfinishing conditions for mirror surface finishing of titanium

To determine mirror surface finishing conditions and efficient and economical superfinishing conditions for pure titanium and titanium alloys, an abrasive film is used when superfinishing is performed under varying conditions. These conditions include the workpiece rotation speed, the oscillation speed, the contact pressure of the roller, the hardness of the roller, and the type of abrasive film. The superfinishing device is applied to polishing a thin and long cylindrical bar. A micro-finishing film and a lapping film were used as abrasive films. A1203 grains or SiC grains were used as abrasives. The surface roughness of a polished workpiece was measured using a stylus-type surface-roughness measuring instrument. As a result, the conditions to improve the polishing surface efficiently include high values for the workpiece rotation speed, oscillation speed and contact pressure. The roller hardness has no effect on the efficient polishing conditions. The mirror finish of a surface can be created using lapping film of 3 μm with Al2O3 grains after polishing to a steady surface roughness under the efficient polishing conditions.

Analysis of Equatorial Currents Observed by Eastern Indian Ocean Cruises in 2010 and 2011

Hydrographic and direct current measurements were made in the Eastern Equatorial Indian Ocean in May 2010 and April 2011 as part of the Eastern Indian Ocean Cruises(EIOC) organized by the South China Sea Institute of Oceanology(SCSIO).Analyses of the shipdrift Acoustic Doppler Current Profiler(ADCP) data indicate that the equatorial currents observed in May 2010 are characterized by a strongly eastward surface current(Wyrtki Jets,WJs) with a maximum velocity of 0.9 m s 1,while that observed in April 2011 is weak and without a consistent direction.The strongly eastward WJ transports the surface water eastward,resulting in a deeper upper mixed layer,as shown in the temperature and salinity profiles.However,it was found that the Equatorial Undercurrent(EUC) in the Eastern Indian Ocean is strong in April 2011 and weak in May 2010.The EUC was located approximately at the position of the thermocline,and it had higher salinity(up to approximately 35.5 psu) than the upper and lower waters.

Development of neutron moisture gauge in China

According to measuring mode (in-hopper,surface,transmitted and scattered neutron moisture gauge),this paper introduced the development and application of neutron moisture gauge in China since 1970s.

Research on intelligent ultrasonic thickness measurement system applied to large area of hull

For a ship in service,seawater corrosion is unavoidable. In order to ensure navigation safety and master the steel plate thickness in service ship,thickness of the ship steel plate must be tested periodically by a scientific method. After consideration of an actual situation of thickness measurement,the bearing mechanism of ultrasonic thickness meter probe has been designed on the basis of wall-climbing robot,and preliminary experiments have been carried out. The device is mainly used for thickness measurement of a large area of ship hull plate when the docking ship has been sandblasted. Efficiency and safety can be improved to finish thickness measurement by using the device.

Large Curved Surface Measurement

The measurement principle of large curved surface through theodolite industry survey system is introduced. Two methods are suggested with respect to the distribution range of curved surface error. The experiments show that the measurement precision can be up to 0.15 mm with relative precision of 3×10 -5 . Finally, something needed paying attention to and the application aspects on theodolite industry survey system are given.

Observations and Simulations of the Circulation and Mixing around the Andaman-Nicobar Submarine Ridge

Using data collected by an Acoustic Doppler Current Profiler （ADCP） on a research cruise in April 2010 in the eastern Indian Ocean, the vertical cun＇ent structures surrounding the Andaman-Nicobar Submarine Ridge （ANSR） are analyzed to investigate the hydrographic responses to the topography in this region. The results show that the topography of ANSR can induce internal waves around the submarine ridge that have a maximum current velocity of 1 m s 1 The spatial struc- ture of the turbulent kinetic energy （TKE） and shear in this region during 2010 is investigated using the high-resolution Princeton Ocean Model （POM） forced by the satellite-based Advanced Scatterometer （ASCAT） winds including the tide, The results show that the model successfully simulates the internal waves around the ANSR. Numerical experiments further indicate that both the topography and tide play an important role in the gen- eration of the internal waves in this region.

TR-PIV Analysis of Turbulent Wake of Hydrofoil with Beveled Trailing Edge

The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS （turbulence integral length scale） of the turbulent wake of hydrofoil with blunt trailing edge is calculated from TR-PIV （time-resolved particle image velocimetry） data. The temporal auto-correlation method based on Taylor hypothesis and spatial correlation method are used to get the TILS information of the turbulent wake of hydrofoil, respectively The comparison of results by two methods indicates that the spatial correlation method is independent on Taylor hypothesis and suitable to strong turbulence and non-isotropic turbulence.

Liquid-level Measurement with Fiber-optic Low Coherence Interferometer: Micrometer-resolution Approach

According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-optic low coherence interferometer in Michelson configuration. The wave front of the reflected light beam is well enough to form an interferogram with a beam reflected from an optic mirror mounted on a stepping scanning-motor. The central peak of the interferogram is read as a measure of the liquid level. Experimental results show that this noncontact method can reach a resolution of ±1.25 μm in the measurement range of 86 mm.

Laboratory Evaluation of the Stiffness Modulus of a Modified Bituminous Concrete with PR PLAST Sahara

Uneven roads surface can be observed on bituminous pavements. This is due to moving loads and climate conditions. If the observed deformations exceed the elastic limit, important damages can occur, so new materials are used to improve the stiffness modulus of bituminous mixtures. To achieve this, a modified bituminous concrete by addition of the PR PLAST Sahara （produced by PR industries and PLAST for Plastic） mainly used in arid region has been studied. The use of this additive at various percentages 0.1, 0.3, 0.6 and 0.9 by weight of bituminous concrete has been investigated to determine its stiffness modulus. An experimental design using the Taguchi tables has been elaborated to reduce the number of tests. Marshall and NAT （Nottingham asphalt tester） tests have been carried out, and a mathematical model of the stiffness modulus has been proposed.

Variations of CO2 Mixing Ratios in the Air near the Ground in the European Territory of Russia

The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk （55.1° N, 36.9° E, 183 m above the sea level） located at a distance of 105 km to the south-west of Moscow are presented. Proposed is a method of experimental data filtering allowing one to separate natural and anthropogenic variations of CO2 concentrations. It is shown that minimal concentrations of CO2 registered in Obninsk and at the continental stations of GAW WMO characterize not only the ＂regional background＂ but also coincide with the data from GAW WMO background stations located in the oceanic regions. In this connection, one can assume that the excess in measured CO2 concentration over its minimal values, making about 5-6 ppm, is connected with an anthropogenic emission, and the continent should be considered as an anthropogenic source of C02.

Development of Online Machining and Measurement System in Die and Mold Manufacturing： Concept and Fundamental Experiments

The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.

Effects of Precipitation on Sonic Anemometer Measurements of Turbulent Fluxes in the Atmospheric Surface Layer

Effects caused by precipitation on the measurements of three-dimensional sonic anemometer are analyzed based on a field observational experiment conducted in Maoming, Guangdong Province, China. Obvious fluctuations induced by precipitation are observed for the outputs of sonic anemometer-derived temperature and wind velocity components. A technique of turbulence spectra and cospectra normalized in the framework of similarity theory is utilized to validate the measured variables and calculated fluxes. It is found that the sensitivity of sonic anemometer-derived temperature to precipitation is significant, compared with that of the wind velocity components. The spectra of wind velocity and cospectra of momentum flux resemble the standard universal shape with the slopes of the spectra and cospectra at the inertial subrange, following the-2/3 and-4/3 power law, respectively, even under the condition of heavy rain. Contaminated by precipitation, however, the spectra of temperature and cospectra of sensible heat flux do not exhibit a universal shape and have obvious frequency loss at the inertial subrange. From the physical structure and working principle of sonic anemometer, a possible explanation is proposed to describe this difference, which is found to be related to the variations of precipitation particles. Corrections for errors of sonic anemometer-derived temperature under precipitation is needed, which is still under exploration.

Quasi-Dammann grating with proportional intensity of array spots for surface hardening of metal

For surface hardening of metal,a quasi-Dammann grating (QDG) is proposed and fabricated to generate array spots with proportional-intensity distribution.To get uniformly hardened band distribution and improve the wear resistance of the sample surface,a three-order QDG is designed to produce array spots with enhanced intensity in the edge.The design and fabrication of the QDG are described in detail.The surface profile of the fabricated grating was measured,which shows that the fabrication error is less than 2%.The laser beam intensity distribution shaped by the QDG was tested by a laser beam analyzer to verify the validity of the QDG.The application of the QDG in the laser surface hardening of metal was experimentally investigated,and the results show that the hardness distribution of the modified layer and the wear resistance of the sample surface are improved significantly by using the QDG.