220 results about "Measurement repeatability" patented technology

The invention relates to a measuring instrument for comprehensive performances of an RV (rot-vector) reducer and belongs to the technical field of precision testing and metering. The measuring instrument comprises two major parts, wherein a mechanical part mainly comprises a precision mounting support of the RV reducer, an input shaft system, an output shaft system, a torque motor, a shaft coupling, a torque sensor, a magnetic powder brake and a brake mounting support; a measuring and controlling part mainly comprises the torque motor, a controller, a driver, an encoder, a subdivision device, a DSI (digital speech interpolation) card, a data acquisition card and an industrial personal computer. The measuring instrument provided by the invention fills in the blank in testing tables for the comprehensive performances of the RV reducers at home and abroad, and has the advantages of reliable performances, good measurement repeability and accurate measured parameters.

The invention provides a device for testing the axial loading / unloading gas permeability of coal, comprising a gas pressurizer, a permeability test unit, an axial pressuring and unloading device and a gas collecting device, wherein the permeability test unit consists of a pressure chamber, a bleeder vent plate, a base, the base is provided with a gas inlet channel, a gas outlet channel is arranged at the top part of the pressure chamber and a piston pressure gauge is fixed on the top part; the permeability test device is arranged in the axial pressuring and unloading device which is composed of a lifting table, a triaxial shear instrument, a proving ring arranged at the upper part of the triaxial shear instrument, and the proving ring is provided with a strain dial gauge and a force-measurement dial gauge; the air tube of the gas pressuring device is connected with an air inlet of the base of the axial pressuring and unloading device; and the air header of the gas collecting device is connected with an air outlet at the upper part of the pressure chamber of the axial pressuring and unloading device. The device in the invention is suitable for permeability test for various coal body structures in particular to coal sample construction under the loading and unloading conditions, and has simple structure, convenient operation and good test repeatability.

The invention provides a protective heat flow meter method thermal conductivity coefficient measuring instrument for realizing the vacuum insulation and thickness measurement function. A test stack body of the measuring instrument comprises a hot plate and a cold plate, wherein a heating film is clamped between the hot plate and a hot plate fixed seat; and the cold plate is similar to the hot plate in structure. A vacuum system consists of a vacuum box, a vacuum pump, a sealing gasket and a sealing bottom plate; and the vacuum insulation function can be realized through the vacuum pump. A thickness measurement module consists of a displacement sensor capable of outputting an electric displacement signal; the displacement signal enters a controller and realizes the function of automatically measuring the thickness of a test piece; and the whole instrument is measured and controlled by a computer. The protective heat flow meter method thermal conductivity coefficient measuring instrument has the beneficial effects that the influence of environment on measurement stability is avoided through a vacuum chamber; meanwhile, the thickness of the test piece is automatically measured to avoid the personal error caused by manual measurement; and the measuring repeatability, the accuracy and the degree of automation of the instrument are improved. The protective heat flow meter method thermal conductivity coefficient measuring instrument can be widely applied to manufacturing enterprises of heat insulation and heat preservation materials, related quality inspection departments and units, institutes of higher learning, research institutes and other scientific research units.

The invention provides a device for measuring a thermal diffusivity. The device comprises an excitation light source, an optical control device, a vacuum heating furnace, a temperature controlling device, a temperature measuring device and a data acquiring and processing device, wherein the excitation light source generates excitation light beams; the optical control device is provided with an optical component group, a light beam mass spectrometer and an energy meter and regulates the energy of the excitation light beams through a replaceable optical element in the optical component group; a heating element for heating a sample is arranged in the vacuum heating furnace; the temperature controlling device is used for controlling the heating temperature of the vacuum heating furnace; the temperature measuring device amplifies a temperature rise signal of the sample measured by a detector through a pre-amplifier and transmits the amplified signal to the data acquiring and processing device; the data acquiring and processing device comprises a data acquiring system and a data processing system; the data acquiring system transmits all acquired data signals to the data processing system; and the data processing system analyzes and repeatedly and theoretically corrects the data signals. The device for measuring the thermal diffusivity designed by the invention has the advantages of reducing the measuring repeatability of the thermal diffusivity of a material to be less than 1 percent, lowering uncertainty of measurement, improving the level of thermal diffusivity measurement and laying foundations for the establishment of a standard thermal diffusivity device in China, the preparation of a standard thermal diffusivity substance and the establishment of a standard thermal diffusivity database.

A standardized acquisition methodology assists operators to accurately replicate high resolution B-mode ultrasound images obtained over several spaced-apart examinations. The methodology utilizes a split-screen display in which the arterial ultrasound image from an earlier examination is displayed on one side of the screen while a real-time “live” ultrasound image from a current examination is displayed next to the earlier image on the opposite side of the screen. A computerized echo edge recognition and tracking methodology automatically identifies ultrasound echo boundaries of the intima-media complex and automatically extracts IMT and arterial dimension measurements, without introducing human measurement error. Measurement accuracy is enhanced by use of sub-pixel resolution for echo edge boundary definition. Utilizing this methodology, measurement of vascular dimensions, such as carotid arterial IMT and diameter, the coefficient of variation is substantially reduced to values approximating from about 1.0% to about 1.25%. Dynamic material properties of arterial structures are measured in a standardized region in accordance with a standardized methodology in order to promote measurement repeatability.

The invention discloses a test system for deformation measurement of a large spacecraft structure under a vacuum and low-temperature environment. The test system includes a vacuum and low-temperature container, a portal supporting mechanism, a low-temperature cantilever moving mechanism, photogrammetry CCD camera and protection cabin assemblies, a test piece supporting mechanism, a low-temperature reference meter, a temperature and air pressure control system, a motion control system, and a measurement data acquisition and processing system; two sets of photogrammetry CCD camera and protection cabin assemblies are symmetrically hung at two ends of the low-temperature cantilever moving mechanism, and 3m-rotation radius and + / -360-degree-reciprocating rotary movement photographing can be realized under the vacuum and low-temperature environment so as to realize the deformation measurement of the large spacecraft structure. With the test system of the invention adopted, the thermal deformation measurement of a certain 5m large umbrella antenna can be completed under a simulated space environment by using photogrammetric techniques, and the repeatability precision of the measurement of spatial point positions can achieve 20 microns.

The present invention relates to a CDSEM (scanning electron microscope) capable of evaluating and presenting the measurement repeatability as a tool with a high degree of accuracy without being influenced by fluctuations in micro-minute shape that tend to increase with the microminiaturization of semiconductor patterns, and to a method for evaluating accuracy of repeated measurement using the scanning electron microscope. There is provided a function whereby when measuring a plurality of times the same part to be measured, by making use of a micro-minute pattern shape such as the roughness included in the pattern, pattern matching with a roughness template image is performed to correct two-dimensional deviation in position of the part to be measured on an enlarged measurement image acquired, and then an enlarged measurement area image is extracted and acquired. This makes it possible to eliminate variation in measurements caused by the micro-minute pattern shape.

An electromagnetic detector for diagnostic - testing compatibility of vehicle internal electromagnetism has electric field probe and magnetic field probe as the two are connected to low noise amplifier respectively through adapter. The detector can be used to diagnose leakage of shielding shell and various components on electronic circuits as well as radiating emission of similar electromagnetic disturbance source, and can be connected to computer through EMI detection receiver.

The invention provides a detecting method of a vehicle GPS velocimeter, belonging to the field of measuring and surveying. The invention uses three light beam light shielding velocity measuring standard devices to directly and actually detect the velocity of a satellite GPS signal and calibrates a standard on the detecting spot; the velocity is memorized by a recording apparatus / a playback apparatus; the playback of the GPS signal in a laboratory is used for ensuring the high-precision vehicle GPS velocimeter to accurately detect the velocity in the laboratory with a special velocity value and trace to the source to the SI base unit of length and time. The invention depends on the GPS signal which is calibrated on the spot to be a quantity transmission object, combines the truth and the reliability of a road test with the convenience and the agility of laboratory simulation, completes the detection such as velocity error detection, repeat detection, and the like, with the high-precision vehicle GPS velocimeter in the laboratory, improves the accuracy and the reliability of detecting results, reduces complex and dangerous vehicle high-speed tests on the spot, is convenient and feasible, improves work efficiency and is easy popularization and application.

The invention provides a wireless low-power-consumption oil well indicator based on a Zigbee network. The wireless low-power-consumption oil well indicator based on the Zigbee network comprises an acceleration and load synchronous sampling unit, a Zigbee wireless transmission unit, an indicator diagram data storage unit, a solar charging unit, a CPU (central processing unit) acquisition control unit, a system parameter configuration unit and a power supply management unit, wherein the acceleration and load synchronous sampling unit consists of a load sensor, an acceleration sensor and an AD (analog to digital) acquisition and conversion chip. The indicator provided by the invention has the advantages that the field measurement repeatability is good, the reliability is high, the working efficiency is improved, the condition of an oil well can be known in real time, and the remote automatic testing and the remote automatic control of a well site are realized.

The invention provides a measuring device for a concrete permeation coefficient. The device comprises a water injecting chamber, a water inlet pipe, an overflow pipe, a water storage container, an upper annular tray, a lower annular tray, a support frame, a lifting mechanism, a permeating water collecting funnel, a permeating water guiding pipe, a weighting container and an intelligent measuring system, wherein the water injecting chamber is communicated with the water storage container through the water inlet pipe and the overflow pipe; the support frame is respectively fixedly connected with the lower annular tray on the upper side and the lifting mechanism on the lower side; the upper annular tray is fixedly connected with the lower edge of the water injecting chamber; a sealing cushion is arranged on the lower surface of the upper annular tray; the lower annular tray is fixedly connected with the upper end of the support frame; a sealing gasket is arranged on the upper surface of the lower annular tray; the permeating water collecting funnel is arranged in the support frame; the bottom of the permeating water collecting funnel is connected with the weighting container through the permeating water guiding pipe; the intelligent measuring system is used for calculating the permeation coefficient of a test piece according to a fixed formula based on the measured time, and corresponding permeating water quality. The measuring device provided by the invention has a simple structure, high measurement precision and high measurement repeatability; the measuring method is quick and convenient and is suitable for the measurement for the concrete permeation coefficient in any places; and the invention also provides a method for measuring the concrete permeation coefficient by adopting the measuring device.

The invention discloses a radial supporting and axial pre-tightening structure for dynamic balance measurement of a motor rotor provided with a bearing. The motor rotor is mounted on a rotor bearing radial support structure in a supported manner for radial support, a rotor bearing axial pre-tightening structure mounted on the rotor bearing radial support structure is used for axial pre-tightening, the rotor bearing radial support structure makes point contact with a cylindrical surface in the outer ring of the motor rotor bearing via tungsten steel bars in bar-shaped grooves of radial support frames at two sides, the rotor bearing axial pre-tightening structure comprises a baffle plate mounted at the outer side surfaces of the radial support frame at the bearing limiting side and an axial pre-tightening assembly mounted at the radial support frame at the bearing abutting side, the baffle plate limits the bearing at one end of the motor rotor in the axial direction, and the axial pre-tightening assembly pre-tightens the bearing at the other end of the motor rotor in the axial direction. The radial supporting and axial pre-tightening structure improves the consistency and stability of the pre-tightening state during dynamic balance measurement of the motor rotor provided with the bearing, the fluctuation degree of dynamic balance measurement of the motor rotor is reduced, and the repeatability and reproducibility of measurement are improved.

The invention discloses a packaging device for applying a constant pre-stress on a fiber grating sensor. The device comprises a base, an adjustable workbench, a fiber clamping mechanism, a pre-stress adjustment device and a stationary mounting plate. The adjustable workbench, the pre-stress adjustment device and the stationary mounting plate are arranged on the base. The pre-stress adjustment device is arranged on one side of the base, and the stationary mounting plate is arranged on the other side of the base. The adjustable workbench is arranged between the pre-stress adjustment device and the stationary mounting plate. An optical fiber is placed on the adjustable workbench. One end of the optical fiber passes through the fiber clamping mechanism to be positioned on the pre-stress adjustment device, and the other end of the optical fiber passes through the fiber clamping mechanism to be positioned on the stationary mounting plate. The device is simple in structure, small in size, low in cost, convenient in operation, and stable and reliable in running. The pre-stress of the device is continuously adjustable. By means of the device, a constant pre-stress is applied onto the optical fiber, so that the measurement accuracy, the measurement repeatability and the measurement consistency of the fiber grating sensor are improved.

The invention provides a device and a method for double-barrelled angle measurement. The device comprises two autocollimators, two autocollimator adjusting supports, a rotary table which is connected with one of the autocollimator adjusting supports through a connecting arm, a pedestal which fixes the other autocollimator adjusting support through a vertical arm, a main shaft, a multidimensional adjusting support, and a bearing seat. The vertical arm is perpendicular to the pedestal. The main shaft is disposed on a center of the rotary table and runs through the rotary table, and is fixed together with the pedestal. The multidimensional adjusting support is fixed right above the main shaft. The bearing seat is fixed right above the multidimensional adjusting support. Combining the double-barrelled test device with the double-barrelled angle measurement method, optical dihedral angles, light beam slip angles, and angle absolute values can be measured. The device and the method are non-contact measurement, the operation process is simple and efficient, with good measuring repeatability and high precision, and repeatability precision can reach 1''. The device and the method can reduce impact of a side-erect placement face and placement precision, and equipment cost is low.

A confocal axial scanning device and a confocal axial scanning method based on a reflection type liquid crystal spatial light modulator relate to a confocal microscope and a scanning method of the confocal microscope, which solve the problems that in an existing axial scanning device and a method, the device is complex in structure and a sample is poor in repeatability of measurement due to the fact that defocus of a measured object is achieved by means of a lens or movement of the measured object along an axial direction. By means of the confocal axial scanning device, the reflection type liquid crystal spatial light modulator is added between a polarization beam splitter and the lens of the existing device, an axial scanning mechanism in a traditional confocal axial scanning device is eliminated simultaneously, and the reflection type liquid crystal spatial light modulator is utilized to replace the axial scanning mechanism. The confocal axial scanning method adopts a mode of utilizing a computer to directly modulate a phase gray-scale figure to adjust wavefront of a light wave in front of the lens so that zoom is achieved, and axial scanning to the measured object can be achieved without axially moving the measurement lens and the measured object. The confocal axial scanning device and the confocal axial scanning method based on the reflection type liquid crystal spatial light modulator are applied to the confocal microscope and the scanning method of the confocal microscope.

The invention discloses a spectrum self-correction photometer and a measuring method thereof. The spectrum self-correction photometer comprises a light entrance, an optical spectroscope, a spectrometer and a silicon photovoltaic cell with a color filter, wherein light to be measured is divided into at least two beams by the optical spectroscope according to a set proportion; one part of beams is received by the spectrometer, the other part of beams is received by the silicon photovoltaic cell, and the light to be measured is simultaneously measured by the beams. The spectrum self-correction photometer of the invention can greatly reduce errors brought by the mismatch of the spectrum, has less reliance on the spectrum of the light to be measured, overcomes the problems brought by inconsistent special spectrum power distribution of a light source to be measured, time-varying luminescence, and the like, has relative smaller system measuring error and random error and high measuring repetitiveness and is calibrated by utilizing an absolute spectrum radiometer as a standard source so that the absolute magnitude transmission chain of an optical radiation degree is very short. The spectrum self-correction photometer has higher precision and reliable absolute magnitude value and can be applied to various optical radiation measuring systems for measuring a plurality of important optical radiation parameters.

The embodiment of the application provides a scanning device and a laser radar. The scanning device comprises a light source, a polarizer, a liquid crystal structure and an electrical structure; the light source emits a laser beam to the liquid crystal structure; the liquid crystal structure receives the laser beam, and reflects the laser beam through a reflecting plane of the liquid crystal structure, the reflected laser beam forms a light spot on a tested object plane, and the liquid crystal structure is located in an electric field. When the laser radar with the scanning device is used forperforming scanning measurement on to-be-tested object plane, the electrical structure forms the electric field by applying the voltage in the preset rule. on the liquid crystal structure; since the liquid crystal structure has a certain mobility, an internal molecule of the liquid crystal structure can produce corresponding deflection when the voltage is applied to the liquid crystal structure, the refractive rate of the liquid crystal structure reflecting plane is changed, thereby changing an exit direction of the laser beam after passing through the reflecting plane, and then changing the location of the light spot on the tested object plane, and realizing the scanning on the tested object plane. The device is higher in precision and has measurement repeatability, control flexibility and stability.

The invention belongs to the technical field of permanent magnet material property measurement and discloses a device for measuring temperature properties of a permanent magnet and a permanent magnet material in an open circuit, comprising a sample box (2), a temperature detection and processing unit (3), an induction voltage generating unit (4), an induction voltage detecting and processing unit (5), a sample drawing and controlling unit (6), a temperature realizing unit (7) and a computer controlling and processing unit (8). The invention further provides a method for measuring the temperature properties of the permanent magnet and the permanent magnet material in the open circuit. The device and the method disclosed by the invention have the beneficial effects that the shape of a sample to be detected is not limited, an application range is wide, the automatic measurement can be realized, the measurement repeatability is good and the measurement accuracy is high, so that the device and the method disclosed by the invention are particularly suitable for measuring the permanent magnet material with smaller measured temperature coefficient.

The invention provides a high-precision 3 mm-waveband single-side-band noise coefficient spread spectrum measurement device and method. The device comprises a down converter module, a microwave and local oscillator combining module, a control interface module and a power module. The down converter module is used for achieving input matching, subsection filtering and down converting of 3 mm signals. The microwave and local oscillator combining module comprises a YTO (YIG tuned oscillator) and a drive and control circuit and is used for generating a combined scanning local oscillator signal source. The control interface module is used for achieving information interaction of a microwave noise coefficient analyzer host and a local spread spectrum measurement device through a USB intelligent interface bus. The power module is used for providing various power sources needed by the local spread spectrum measurement device. By the adoption of the device and method, the problems that the system is huge, the measurement accuracy is poor, the measurement repeatability and consistency cannot be guaranteed easily, the purchase and maintenance cost is high and operation is difficult in an existing 3 mm-waveband noise coefficient testing scheme are solved.

The invention discloses an electro-optic crystal Z axis deviation angle measurement device and a measurement method. The device comprises a laser (101), a microscope objective (102), a pin hole (103), an adjustable diaphragm (104), a collimating lens (105), a polarizer (106), a reflector (107), a beam splitting cube (108), an optical screen (109), a first lens (110), a to-be-measured crystal (111), a second lens (112), an analyzer (113), an imaging lens (114), a detector (115) and a computer processing system (116) which are placed in sequence along an optical path, wherein the polarizer (106) and the analyzer (113) have vertical polarized directions; the first lens (110) and the second lens (112) are strictly conjugate; and the beam splitting cube (108), the reflector (107), the to-be-measured crystal (111) and the optical screen (109) form a Michelson interference system. a Michelson interference principle is used for realizing precise crystal positioning, image matching algorithm is adopted for realizing melatope center calculation, and precise electro-optic crystal Z axis deviation angle measurement can be completed. Compared with other devices and methods, the device and the method of the invention have the advantages of high measurement precision, simple measurement method, small measurement system errors and good measurement repetition.

The invention relates to a fluid viscosity (rheological property) measuring instrument which comprises a cascading motor (1), an air bearing (2), a velocity sensor (3), a support (4), a measuring head rotor (5), an outer cylinder (6), a calculation and display unit (7) and a gas source (8). The velocity attenuation of the measuring head rotor (5) in the fluid to be measured has the corresponding relation with the viscosity of the fluid to be measured, and the viscosity of the fluid to be measured can be worked out according to the corresponding relation by detecting the rotating speed of the measuring head rotor (5) at any two corresponding moments. The fluid viscosity (rheological property) measuring instrument has the characteristics of wide measurement range, high measurement accuracy, good measurement repeatability, high measurement speed and the like.

The invention discloses a water comprehensive characterization method for oil-containing sludge. According to the conventional measurement method, the measurement time is long, the efficiency is low and the operation is complicated, samples cannot be repeatedly tested, and toxic and organic chemical solvents are used in a measurement process. According to the water comprehensive characterization method, an oil-containing sludge sample with a certain weight is directly and flatly arranged at the bottom of an experiment container; temperature is controlled by a dynamic stability control (DSC) temperature control program; the oil-containing sludge is measured by a differential scanning calorimety, so that heat flow of crystallization and melting of emulsified water in the oil-containing sludge at different temperatures can be obtained; the stability and the salt content of the emulsified water in the oil-containing sludge can be quantitatively judged according to a DSC curve; the water content and the water drop distribution of the oil-containing sludge sample are quantitatively calculated according to the DSC curve and a formula. The water comprehensive characterization method can quickly obtain information such as the stability of the oil sludge, the water content, the water drop distribution and the salt content, and is high in measurement repeatability and low in measurement cost.

The invention discloses an uncertainty determination method of a spacecraft total leak rate test result. The method comprises the following steps of: determining an uncertainty source; determining uncertainty component introduced by a system effect; determining uncertainty component introduced by measurement repeatability; determining synthesis standard uncertainty; and determining expansion uncertainty. By the system, the uncertainty caused by the system effect and the uncertainty caused by the measurement repeatability are firstly evaluated, and the synthesis standard uncertainty and the expansion uncertainty are obtained according to the test result by utilizing an uncertainty basic theory. Direct basis is provided for reliability evaluation of the spacecraft total leak rate test result.

The invention discloses an apparatus for measuring angle of divergence between a normal of light passing surface of electro-optical crystal and Z axis. The measuring apparatus includes a laser, a first lens, a space filter, a second lens, a polarizer, a third lens, a beam splitter, a digital optoelectronic inner focus autocollimator, a fourth lens, an analyzer, an imaging lens, a detector and a computer processing system. According to the invention, the theory of conoscopic interference is adopted to detect a to-be-measured electro-optical crystal in a non-contact and damage-free manner, such that the apparatus ensures no introduction of scratches on the surface of the to-be-measured electro-optical crystal in the course of the measured, and is suitable for detecting electro-optical crystals having large caliber. Also, according to the invention, the digital optoelectronic inner focus autocollimator is adopted to calibrate and detect the direction of the optical axis of a light beam, such that the apparatus guarantees that a detecting light beam is incident in the perpendicular direction to the to-be-measured electro-optical crystal, and the apparatus has the advantages of high measurement precision, excellent measurement repetitiveness and wide application value.

The invention discloses a method for rapidly measuring the content of trace methylbenzene in benzene based on a Raman spectrum. The method comprises the following steps: preparing training samples by using benzene and methylbenzene, wherein the benzene in the training samples contains different contents of methylbenzene; measuring the Raman spectrums of the training samples; pretreating the Raman spectrums; selecting the Raman spectrums at methylbenzene characteristic peak wave bands, and establishing a quantitative calibration model of methylbenzene contents and Raman spectrum intensities by a linear regression method. According to the method, the Raman spectrum of the sample which is to be measured and has the unknown methylbenzene content is measured; the Raman spectrum is pretreated; the Raman spectrum at the methylbenzene characteristic peak wave bands is input into the quantitative calibration model, so that the predicted value of the methylbenzene content of the sample to be measured can be obtained. The method is simple and convenient to operate, high in detection speed, clean and environment-friendly, has higher measurement accuracy and better measuring repeatability, and is especially suitable for real-time and online detection for the content of the trace methylbenzene impurity in the industrial benzene production process.

The invention discloses a pavement water-seepage standard device and a pavement water-seepage coefficient measurement method, and overcomes the deficiencies that measurement standards of a conventional pavement water-seepage meter are deficient, and a measurement value cannot trace to a source. The device comprises a water-seepage container (10), monitors (30), a timer (40) and a controller (50); the monitors (30) are used for monitoring a volume change of a liquid in the water-seepage container (10); the timer (40) is used for recording the water-seepage time corresponding to the volume change; the controller (50) is used for calculating to obtain a water-seepage coefficient according to the volume change and the water-seepage time. The pavement water-seepage standard device and the pavement water-seepage coefficient measurement method greatly improve the standardization degree of the pavement water-seepage meter, realize full automation of the water-seepage coefficient measurement process, have rapid response and high accuracy, can realize verification and calibration of water-seepage coefficient measurement errors, measurement repeatability and other key measurement parameters, and can trace to the source of the quantity value of the pavement water-seepage meter on the significance of metrology.

The invention discloses a high-repeatability quasi-distributed sensing system based on a CP-phi(OTDR) and an implementation method of the system and belongs to the field of optical fiber sensing measurement technologies. The system comprises a laser module, a coupler, an optical signal modulation module, a signal detection module, an optical circulator and a to-be-detected sensing optical fiber, wherein the optical signal modulation module modulates an optical signal into N positive and negative chirped pulse optical signals located in the same frequency band or different frequency bands, thesignal detection module generates a beat frequency signal by use of a reflected optical signal and a local oscillation optical signal input by the coupler, the signal detection module inputs the beatfrequency signal into a signal demodulation module for demodulation and output, and disturbance information of the reflected optical signal is obtained. Through the system, measurement repeatability is improved by N times while a high spatial resolution is guaranteed, double-channel detection is not needed, only a single channel is needed, and therefore the complexity of the system is lowered.

The invention provides a small-angle block gauge which is suitable for a working angle of less than 1 degree and meets the calibration and the small-angle detection of a small-angle measuring instrument. The small-angle block gauge comprises an angle block gauge base fixed above an installation base plate; two installation surfaces are spaced at the same side surface of the angle block gauge basein the vertical direction; an upper reflector is installed in the upper installation surface; a lower reflector is installed in the lower installation surface; a transmission refractor is arranged before the upper and the lower reflectors; and the transmission refractor is also fixed above the installation base plate. The small-angle block gauge has the advantages of novel structure, convenience for installation, stable performance, high degree of accuracy, good repeatability of measurement and easiness for the reproduction of angle; and the small-angle block gauge is applied to the measurement and the calibration of the small-angle measuring instrument and can effectively avoid the problem of the alignment of an optical shaft during the conversion of a measuring surface so that the installation complexity of the angle block gauge is reduced.

An optical beam profiler using a spatial light modulator and photodetector. In an embodiment, the spatial light modulator is a two-dimensional (2-D) small tilt digital micromirror device. The profiler features fast speed, digital controls, low polarization sensitivity, and high measurement repeatability. The 2-D multi-pixel device-based profiler allows the use of several beam profile measurement concepts including moving knife edge, scanning slit, moving pinhole, variable aperture, and 2-D photodiode array. The proposed digital optical beam profiler can be implemented with any type of digitally operated 2-D spatial light modulator device such as using liquid crystals, magneto-optics, multiple quantum wells, electro-optic polymers, and photonic crystals.