Chinese Version Light学术出版中心
Latest Issue
Issue 3 ， 2003
-
Present status of research on space optical remote sensors at CIOMP
Abstract：This paper is to review our space optical remote sensor(SORS) technologies including optical materials, optics fabrication and coating, optical testing, system assembly and final testing, and space environment simulation experiment conducted in our institute. The primary parts of the fabrication and testing facilities and results are described in detail.Keywords：space optics;optical remote sensing;optical material;optical fabrication and inspection;optical system assembly and testing- 84
- |
- 11
- |
- 0
Published：2020-08-12 -
Precision nanometrology of a large area microstructured metrology surface
Abstract：The authors have been working on a newsurface encoder for detecting multi-degree-of-freedom(MDOF) translational and tilt motionsof precision stages[1]. The surface encoder con-sists of two fundamental elements: a sinusoidalmicrostructured metrology surface, which is re-ferred to as the angle grid, and a two-dimension-al (2D) slope sensor[2-3].- 39
- |
- 6
- |
- 0
Published：2020-08-12 -
Wireless networked microsensor and its embedding system
Abstract：The classification and architectures of wireless networked microsensors, and the architec-tures of two wireless microsensors with Bluetooth, RF-MEMS antenna and embedding system in par-tucular, are discussed in detail. The technical requirements for wireless networked microsensors andassociated key techniques, including adaptive brequency-hopped spread spectrum and self-configura-tion Bluetooth networking, are discussed with emphasis on stability and reliability of wireless commu-nication and wireless networking schemes including real-time connectivity to internet. A wireless net-worked microsensor can be designed with an embedding system to achieve environmental monitoringand transfer of measurements through wireless network communication. Low-level drivers, schedulersand Bluetooth high-level protocols can be designed by selecting appropriate 32 bits embedded processorand clinus operating system. The whole design and operating process of a wireless netwokred mi-crosensor and its embedding system are illustrated with a wireless remote image surveillance systemused as typical example.Keywords：wireless microsensor;networking;embedded system;bluetooth- 69
- |
- 6
- |
- 1
Published：2020-08-12 -
2-photon 3-D microfabrication technology and its experimental system
Abstract：The 2-photon 3D microfabrication technology employs the 2-photon excitation locally induced between the femtosecond laser and the material to achieve 3D shaping through point to point scan. For the probability of two-photon excitation is in direct proportion to the squared intensity of laser, both the femtosecond laser with extremely high pulse intensity and the microscope with high numerical aperture become critical components in the system, and therefore much detail information is provided on this particular aspect. Some preliminary experimental results obtained with the machining system are presented as well.Keywords：two-photon excitation;photoploymerization;femtosecond laser;three-dimensional microdevice- 62
- |
- 6
- |
- 16
Published：2020-08-12 -
Novel micromachined patch antenna for mobile communication
Abstract：The rapid development of wireless communications worldwide results in a huge demand forminiaturized antenna with excellent performance to send and receive wireless signals to and from com-munication devices. Microstrip patch antennas are used in a variety of applications for their salient fea-tures. By sandwiching a layer of Teflon between the silicon wafer and the ground plane, the novel mi-cromachined shortened stacked patch antenna printed on high-index wafer has superior performance o-ver those of traditional design, while its bandwidth has been increased by as much as 8.6 %, and itslength of patch has been miniaturized to only an eighth wavelength. The radiation patterns show thateven if the antenna is on a ground plane of approximately the size of a handset phone circuit board,most of the radiation is directed away from the user's head, and the wide beamwidth can ensure wideangular coverage. The antenna micromachined in a silicon wafer can also be integrated with Si andGaAs IC without affecting any of the circuit requirements.Keywords：mobile communication;RF-MEMS;microstrip antenna;micromachining- 30
- |
- 5
- |
- 0
Published：2020-08-12 -
Laser profilometer
Abstract：The laser profilometer based on the Michelson interferometry principle, has its platform driven by a stepper motor for fast rough position and expansion of measuring range, and by piezoelectric ceramic for precision positioning with a repetitive positioning accuracy of 10 nm. A common path interference system, which is not sensitive to mechanical vibration and temperature drift, is used in the measuring optical path. The laser profilometer has a measuring range of 20 mm×20 mm×0.4 mm, a longitudinal resolution of 0.32 μm, and a lateral resolution of 0.5 μm.Keywords：profilometer;piezoelectric ceramic;laser interferometry- 84
- |
- 7
- |
- 8
Published：2020-08-12 -
Deep aspheric testing based on phase-shift electronic Moir? patterns
Abstract：The resolutions of CCD camera and digital computer are limited by Nyquist frequency whendeep aspheric wavefronts are tested using phase-shifting technique. A new powerful technique basedon parallel generations of three phase-shift patterns through electronic multiplication with computer-generated graftings and low pass filtering, is proposed for measuring wavefronts with large departuresfrom a reference sphere such as those encountered during testing of steep aspheric surfaces. The phasedistribution of aspheric surfaces is obtained using a three-step phase-shifting algorithm.Keywords：Fringe analysis;moire patterns;compensating testing- 38
- |
- 5
- |
- 0
Published：2020-08-12 -
Comparison of genetic algorithm based evaluation of roundness with evaluation of roundness based on least squared method
Abstract：The evaluation of roundness based on genetic algorithm method(GAM) is compared with the evaluation of roundness based on least square method(LSM) with their advantages and drawbacks discussed in detail using the model proposed, which features bounds control data to simulated the maximum inscribed and maximum circumscribed circles defined under minimum zone conditions, and randonly produced data to simulate the randomness and uncertainties of test points under actual conditions. The computational results show that the accuracy of GAM is better than that of LSM.Keywords：genetic algorithm-based method (GAM);least squared method (LSM);circularity- 56
- |
- 7
- |
- 4
Published：2020-08-12 -
Power supply to infrared diode in ESG
Abstract：An AC power supply was designed to improve the stability and accuracy of ESG. The structure of constant power supply circuits is briefed, and the design of AC power supply circuits is emphatically described in detail with simulation results and actual measurements given. The tested results show that at a normal atmospheric temperature, the constant current accuracy of the designed power supply circuit can go up to 0.8%.Keywords：ESG;infrared diode;AC;power supply;PSPICE- 51
- |
- 6
- |
- 0
Published：2020-08-12 -
How to define noise and associated performance parameters for infrared detector and infrared focal plane array detectors
Abstract：Different opinions are presented on the definition of noise and associated performance parameters for infrared detectors and infrared focal plane array detectors in Chinese National Standards GB/T 13584 and GB/T 17444. Without background radiance and signal irradiance level given, the definition of noise in the Chinese National standard can easily lead to fuzzy conceptions of noise and associated performance parameters. When the signal is very strong, the photon noise predominates, signal to noise ratio is not directly proportional to signal level, and care must be exercised in deriving NEP and D* from signal to noise ratio. When the signal is weak, and the photon noise can be ignored, it is very simple to derive NEP and D* from signal to noise ratio.Keywords：infrared detector;infrared focal plane array detector;property parameters of detector- 63
- |
- 8
- |
- 10
Published：2020-08-12 -
Causes for hysteresis and nonlinearity of piezoelectric ceramic actuators
Abstract：The displacement mechanisms of electrostrictive effect, inverse piezoelectric effect and ferroelectric effect are systematically analysed in a microcosmic way, and the results of analyses indicate that the displacement mechanisms of these three effects are totally different; the displacement of piezoelectric ceramic actuators is mainly due to inverse piezoelectric effect and ferroelectric effect; the contribution of electrostrictive effect to the displacement is so little that it can be neglected; pure inverse piezoelectric effect is linear, while ferroelectric effect is hysteretic and nonlinear. It is pointed out that the non 180皌urn of ferroelectric domain and its incomplete reversibility are the essential causes for nonlinearity and hysteresis of piezoelectric ceramic actuators respectively. The influences of driving voltage amplitude, driving voltage frequency, number of driving voltage cycles, and walfer thickness on the hysteresis and nonlinearity of piezoelectric ceramic actuators are studied through expeirments.Keywords：actuators;piezoelectric ceramics;hysteresis;nonlinearity- 43
- |
- 7
- |
- 21
Published：2020-08-12 -
Subdivision control technique in synchronic radiation beam position monitoring system
Abstract：The PWM subdivision driving technique based on a single chip machine control is used to achieve the high-precision movement and location of the detection and adjustment mechanism. The application of different currents to the two-phase windings of the stepper motor causes the constant amplitude uniform rotation of resultant current vector to realize the 32 subdivision microstep driving. The nonlinear error of stepper motor windings results in the nonuniformity of step angle after subdivision, and the maximum error goes up to 24.8%. After the error is corrected by lagrange polynominal fitting, the subdivision accuracy is improved, and the maximum error is 8.1%.Keywords：stepper motor;PWM;subdivision driving- 90
- |
- 8
- |
- 3
Published：2020-08-12 -
Experimental study on the displacement mechanism of a hopping locamotion mechanism
Abstract：The displacement mechanism of a new hopping locomotion mechanism driven by small vibratory motors is detailed. The joint application of the periodical centripetal force generated by the rotation of the ecentric inside the motor and the intermittent friction with the working surface brings about the hopping locomotion of the mechanism. The combined operation of the two motors located in different positions makes the linear movement and rotation of the mechanism at adjustable speeds possible. It is verified through a series of experiments that the hopping locomotion mechanism can freely move in a 2D plane.Keywords：hopping;friction;eccentricity- 63
- |
- 9
- |
- 0
Published：2020-08-12 -
Use of pre-embedded parts to improve the performance of carbon fibre framework
Abstract：The use of pre-embedded parts to improve the performance of carbon fibre framework is discussed by summarizing the major characteristics of carbon fibre and presenting the structure of several pre embedded parts. A carbon fibre framework with overall dimensions of 1 200 mm?790 mm?695 mm and mass of 41 kg has been designed and fabricated, and subjected to both sine and random vibration tests. The results show that the carbon fibre framework can withstand an acceleration of 20.4 g.Keywords：carbon fiber;pre-embedded part;vibration test- 76
- |
- 6
- |
- 7
Published：2020-08-12 -
Use of excimer to correct compound myopic astigmatism
Abstract：With the relationship between the coordinate used to construct the model and the coordinate used to control excimer laser beams established by the astigmatic axis, a cornea ablation model was constructed using the sphere and the cylinder for correction of refractive errors of compound myopic astigmatism. The 33 eyes with compound myopic astigmatism has a mean sphere of -6.00?2.14 D, a mean spherical equivalent refraction of -6.43?2.18 D, a mean cylinder of -0.86?0.41 D, and a mean uncorrected visual acuity of 0.12?0.08 before LASIK operation using the model, and had a mean sphere of -0.22?0.74 D, a mean spherical equivalent refraction of -0.43?0.85 D, a mean cylinder of -0.42?0.62 D, and a mean uncorrected visual acuity of 0.88?0.18 one day after LASIK operation using the model. Practice proved the mathematic cornea ablation model is safe and effective for correction of compound myopic astigmatism.Keywords：compound myopic astigmatism;corneal;mathematical model;LASIK- 44
- |
- 7
- |
- 10
Published：2020-08-12 -
Factors affecting the zenith blind spot of an altitude-azimuth optoelectronic telescope
Abstract：The formation of the zenith blind spot of an altitude-azimuth optoelectronic telescope is analysed using a conventional algebraic method, and the results indicate that the scope of the zenith blind spot is determined by the maximum azimuth angular velocity of the tracking gimbal and the flight altitude and flight speed of the target. The analysis made in the astronomical sperical coordinates shows that the limit on the maximum azimuth angular velocity of the tracking gimbal is the primary cause for the zenith blind spot of an alitude azimuth optoelectronic telescope. Specific data were obtained by tracking targets with different declinations at latitude 60皀orth, and it is verified by comparing the varations of azimuth and pitch angular velocities near the zenith that the maijor factor affecting the zenith blind spot is the azimuth angular velocity of the tracking gimbal.Keywords：altitude-azimuth form;Tracking servo system;zenith blind spot- 73
- |
- 9
- |
- 2
Published：2020-08-12 -
Design of the wedge leveller
Abstract：For the purpose of precision levelling and accuracy maintenance under big vertical load and azimuth torque, a wedge leveller has been designed against 4 criteria based on its operating requirements, so that the static friction counteracts the azimuth torque, the increased wedge area carries the big vertical load, and the high transmission ratio and self locking of the wedge screw mechanism can be used to achieve precision levelling and accuracy maintenance. The levelling accuracy of the wedge leveller designed is 1″ when the vertical load is 15 t, the azimuth torque is 10,000 N.m, and the levelling angle is not less than 1°.Keywords：leveller;incline stiffness;friction- 50
- |
- 5
- |
- 3
Published：2020-08-12 -
Geometric degradation produced during DCT compression of images with high spatial redundancy
Abstract：The objective image quality evaluation of DCT(discrete cosine transform) compressed images is usually achieved using MSE(mean square error) and PSNR(peak signal to noise ratio) with the geometric degradation of images out of consideration, which is the very key to the optical measurement system based on position information. DCT compression experiemnts made with two images with high spatial redundancy show that MSE and PSNR do not change much under 4?4 processing block and 1:2 compression ratio, but there is a geometric degradation of 1 or 2 pixels; considering the total error of the optical measurement system is generally only 1 or 2 pixels, a change in position of more than 1 pixel resulting from DCT compression will have a significant influence on the accuracy of the measurement system. A good deal of attention should, therefore, be paid to geometric degradation during DCT compression.Keywords：DCT compression;MSE;PSNR;image geometric degradation- 61
- |
- 6
- |
- 0
Published：2020-08-12 -
Edge detection based on fuzzy inference
Abstract：The presence of an edge can be judged from the sudden changes in the image intensity by following the IF THEN fuzzy inference rules while impulse noises are suppressed. Experimental results show that image edges can be properly by following a few fuzzy inference rules.Keywords：edge detection;fuzzy inference;image processing- 56
- |
- 8
- |
- 6
Published：2020-08-12
Loading...
0