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2005 年 第 5 期
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Design and simulation of a tuning fork micromachined gyroscope with slide film damping
摘要：A novel tuning fork micromachined gyroscope, based on slide-film damping, is presented. The electrostatic driving gyroscope consists of two driving masses each of which supports one sensitive mass. The angular rate is sensed by the differential capacitances consisted of movable bar electrodes and fixed bar electrodes located on the glass wafer. The gyroscope can operate at atmospheric pressure with slide film damping in the driving and sensing directions, eliminate vacuum packaging and restrain cross-axis acceleration signal. The results of design and simulation show that the driving and sensing mode frequencies are 3 106 Hz and 3 175 Hz,respectively, and the Q-values in driving and sensitive modes are 1 721 and 1 450 respectively. The design resolution is 0.025°/s.关键词：micromachined gyroscope;slide film damping;design simulation- 32
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发布时间：2020-08-12 -
Organic optoelectronics:materials,devices and applicati
摘要：The interest in organic materials for optoelectronic devices has been growing rapidly in the last two decades. This growth has been propelled by the exciting advances in organic thin films for displays, low-cost electronic circuits, etc. An increasing number of products employing organic electronic devices have become commercialized, which has stimulated the age of organic optoelectronics. This paper reviews the recent progress in organic optoelectronic technology. First, organic light emitting electroluminescent materials are introduced. Next, the three kinds of most important organic optoelectronic devices are summarized, including light emitting diode, organic photovoltaic cell, and photodetectors. The various applications of these devices are also reviewed and discussed in detail. Finally, the market and future development of optoelectronic devices are also demonstrated.关键词：organic optoelectronics;material;device;application;overview- 82
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发布时间：2020-08-12 -
Performance of a serial-connection multi-chamber piezoelectric micropump
摘要：The concept and structure of serial-connection multi-chamber (SCMC) micropumps with cantilever valves is introduced. The SCMC micropump, which can be manufactured using conventional production techniques and materials, has a multi-layer circular planar structure. The border-upon piezoelectric actuators of a SCMC micropump work in anti-phase, as a result the pumping performance is similar to that of several single-chamber pumps running in series. The theoretical analysis shows that the pumping performance of a SCMC micropump depends not only on the characteristic and geometrical parameters of the piezoelectric actuators, but also on the number of pump chambers. Both flowrate and pressure of a SCMC pump can be enhanced to a certain extent. Four piezoelectric micropumps with different chambers were fabricated and tested. The testing results show that the enhancing extents of the flowrate and pressure of a SCMC piezoelectric micropump are different. The maximum flowrate and pressure of the four-chamber pump achieved are 2.5 times and 3.6 times those of the single-chamber pump achieved.关键词：micropump;piezoelectric actuator;multi-chamber;cantilever valve- 32
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发布时间：2020-08-12 -
Magnetic-fluid microelectromechanical light modulator
摘要：A new microfluidic microelectromechanical light modulator using a magnetic fluid is introduced. The optical reflection from the device is modulated by applying an electric current into an electrode, which is enclosed by ferromagnetic thin films as in an inductive head for a magnetic data storage device. The magnetic field produced by the current exerts a magnetic force on the magnetic fluid and drives the fluid to cover the cell surface. The surface tension of the fluid provides a restoring force when the field is reduced. The actuation of the fluid is completed in about 12 ms for both thin-to-thick and thick-to-thin fluid film switchings by magnetic forces and surface tension forces, respectively. It was observed that the switching speed was almost independent of the driving current, and no considerable thermal effect were observed when driven by a current up to 100 mA.关键词：MEMS;microfluidic;magnetic fluid;light modulator;display;flat-panel display- 38
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发布时间：2020-08-12 -
Design on hopping locomotion mechanism
摘要：A new type of locomotion mechanism is introduced in this paper. With vibrating motors used in controling the movement of the hopping locomotion mechanism, the simple hopping locomotion mechanism had two motors, when the current went through the vertical motor, the vertical motor would vibrate to cause the mechanism to go forward, and when the current went through the horizontal motor, the mechanism will go around itself. A spring was added to the mechanism to change the natural frequency of the mechanism, when the frequency of the motor was equal to the natural frequency of the mechanism, the mechanism would hop resonantly. With the resonant hopping, the load of the mechanism was greatly enlarged, and some sensors could be added to the mechanism. Optical sensors were used to detect the infrared source, the current that went through the sensors related to the distance between the infrared light. Three optical sensors was put on the left, right and the front the mechanism, when the mechanism detect the special infrared source, it would turn itself to the light, and go forward to the light. The experiments of the mechanism shown that the mechanism could work well on different surfaces freely, and the resonant hopping locomotion mechanism with infrared sensors could move to the special light by automatic regulation. Experimental results and theoretical studies demonstrate that the innovative design for hopping locomotion mechanism is superior.关键词：robot hopping locomotion mechanism;friction;infrared sensor;resonance- 33
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发布时间：2020-08-12 -
Waveguide electro-optic modulators based on self-assembled material systems
摘要：Fabrication and characterization of electro-optic modulators based on the novel organic electro-optic materials composed of self-assembled superlattices (SAS) were presented, both wet-dipping self-assembly and vapor phase deposition approaches were discussed. Prototype waveguide electro-optic modulators were fabricated using SAS films integrated with low-loss polymeric materials functioning as partial guiding and cladding layers.Promising electro-optic thin film materials including DTPT and PEPCOOH grown from the vapor phase were used for fabrication and test of electro-optic prototype modulators. Finally,the EO coefficient of tens of pm/V was obtained,which can sufficiently support high-speed and small size EO modulators.关键词：electro-optical modulator;waveguide modulator;self-assembled material;superlattice;vapour deposition- 28
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发布时间：2020-08-12 -
Optimization of structural parameters for spatial flexible redundant manipulators with maximum ratio of load to mass
摘要：Optimization of structural parameters aimed at improving the load carrying capacity of spatial flexible redundant manipulators is presented in this paper. In order to increase the ratio of load to mass of robots, the cross-sectional parameters and constructional parameters are optimized respectively. The cross-sectional and configurational parameters are optimized simultaneously. The numerical simulation of a 4R spatial manipulator is performed. The results show that the load capacity of robots has been greatly improved through the optimization strategies proposed in this paper.关键词：flexible manipulator;structural parameter;ratio of load to mass;optimal design- 45
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发布时间：2020-08-12 -
Experimental research and analysis of three-finger micro-tweezers
摘要：A new type of three-finger micro-tweezer driven by electro-static force was developed for stable manipulation and assembly of micro devices. The whole system consists of micro-tweezers and a specially designed high frequency AC power supply. The free end of the fingers closes and opens with the increase and decrease of the voltage. The tweezers can grasp and manipulate micro objects at size from 30~100 μm. A quantitative simulation method based on boundarx element method(BEM) and equation of energy conservation is introduced to analyze the non-linear behaviors of the tweezer closure. The simulation results agree well with the experimental data.关键词：three-finger micro-tweezer;particulation;manipulation;simulation- 33
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发布时间：2020-08-12 -
Adaptive segmentation of digital mammograms through reinforcement learning
摘要：An approach based on reinfocement learning for the automated segmentation is presented. The approach consists of two modules:segmentation module and learning module. The segmentation module uses the region-growing algorithm combined with the smooth filtering and the morphological filtering to segment mammograms. The learning module uses the segmentation output as the feedback to learn to select the optimal parameter settings of the segmentation algorithm according to the image properties using reinforcement learning techniques. The approach can adapt itself to various kinds of mammograms through training and therefore obviates the tedious and error-prone tuning of parameter settings manually. Quantitative test results show that the approach is accurate for several kinds of mammograms. Compared to previously proposed approaches,the approach is more adaptable to different mammograms.关键词：adaptive image segmentation;digital mammography;reinforcement learning- 64
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发布时间：2020-08-12 -
Calibration of line structured light vision system based on camera’s projective center
摘要：Based on the characteristics of line structured light sensor, a speedy method for the calibration was established. With the coplanar reference target, the spacial pose between camera and optical plane can be calibrated by using of the camera's projective center and the light's information in the camera's image surface. Without striction to the movement of the coplanar reference target and assistant adjustment equipment, this calibration method can be implemented. This method has been used and decreased the cost of calibration equipment, simplified the calibration procedure, improved calibration efficiency. Using experiment, the sensor can attain relative accuracy about 0.5％, which indicates the rationality and effectivity of this method.关键词：line structured light sensor;vision system;coplanar reference target;calibration;light plane- 39
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发布时间：2020-08-12 -
An algorithm of image segmentation for overlapping grain image
摘要：Aiming at measurement of granularity size of nonmetal grain, an algorithm of image segmentation and parameter calculation for microscopic overlapping grain image was studied. This algorithm presents some new attributes of graph sequence from discrete attribute of graph,and consequently achieves the geometrical characteristics from input graph, and the new graph sequence in favor of image segmentation is recombined. The conception that image edge denoted with "twin-point" is put forward, base on geometrical characters of point, image edge is transformed into serial edge, and on recombined serial image edge, based on direction vector definition of line and some additional restricted conditions, the segmentation twin-points are searched with, thus image segmentation is accomplished. Serial image edge is transformed into twin-point pattern, to realize calculation of area and granularity size of nonmetal grain. The inkling and uncertainty on selection of structure element which base on mathematical morphology are avoided in this algorithm, and image segmentation and parameter calculation are realized without changing grain's self statistical characters.关键词：image segmentation;twin-point;serial edge- 44
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发布时间：2020-08-12 -
Effects of fabricated error on transmission performance of double layer frequency selective surface configuration
摘要：Based on the experimental results, in which the fabricated error of the double layer frequency selective surface (FSS) leads to the transmission loss and the resonant frequency leaves away the design resonant frequency, the inter-layer separation distance (ISD) and the unit cell aligning error (UAE) were used as main variables to study the transmission performance attenuation of the double layer FSS configuration. The numerical analysis model for ISD and UAE was established and also was used to simulate the ring unit cell FSS transmission performance by the finite element and periodic moment methods. The double layer ring aperture FSS configuration designed was used as the numerical model. As a result of the numerical analysis, it is shown that both ISD and UAE produce insertion transmission loss (ITL) and insertion phase distortion (IPD) directly. Furthermore, ISD results in more loss of the amplitude of the transmitted signal for the FSS than UAE. It is significant for the designer of the multiplayer FSS to assign the fabricated error of the FSS dielectric layers. The UAE introduces the insertion phase variation badly.关键词：double layer frequency selective surface;inter-layer separation distance;insertion transmission loss;insertion phase delay- 31
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发布时间：2020-08-12 -
Experimental investigation of laser-produced-plasma EUV source based on liquid target
摘要：A laser-produced plasma(LPP) source was built using liquid as target and a Nd:YAG laser as the irradiation laser, and the LPP source's radiation with ethanol and acetone target respectively was measured by an AXUV100 silicon photodiode combined with a McPHERSON model 247 grazing incidence monochromator of the resolution Δλ≤0.075 nm and the wavelength scanning interval 0.5 nm. Both ethanol and acetone target LPP source had EUV emission at 11~20 nm wavelength. The comparison between the spectra of the two kinds of target materials shows that all the two kinds of target source's spectra are the result of oxygen ions' transitions under current source's parameters, but the spectrum intensity from different target sources is different. The spectra intensity from the ethanol target is higher than that from the acetone target. In addition, the target liquid is forced into the vacuum chamber by the background pressure supported by the connected external high pressure gas, and the influence of the background pressure on the source's intensity is investigated.关键词：laser-produced plasma;spectrum;spectral measurement;soft X-ray;EUV source;liquid target Optics and Precision Engineering Vol.13 No.5 QI Li-hong;et al:Experimental investigation of laser-produced-plasma ……- 48
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发布时间：2020-08-12 -
Axial intensity in a fiber-optic confocal microscope
摘要：A fiber-optic confocal microscope has been analyzed by Fourier optics.It is found that the detected light intensity has three parts,each of which is depennted on the coupled lens,the detective lens,and the part comprised of the fiber and the microprobe.The simulated results show that the less the value of the parameter A is,which is dependent on the fiber and microprobe,the higher the axial resolution of the system is. For the case,as A→∞, the axial resolution is zero,which is corresponding to the conventional microscope.as A≤1,the axial resolution changes slightly,and is close to the optimal value,which is corresponding to the perfect confocal microscope.when the reflective loss takes place at the end of fiber,the contrast of axial intensity will decrease.All that will help the design of endoscope with confocal microscope at cellular level.关键词：confocal microscope;point spread function(PSF);single-mode fiber;object function;axial intensity- 34
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发布时间：2020-08-12 -
Experimental research on dual polarized laser optical feedback microscope
摘要：The principle of laser optical feedback microscope was presented and demonstrated. Three methods to advance the vertical resolution of laser optical feedback microscope were experimentally studied. The first one is to detect the two polarized lights’ intensities separately with a Wollaston prism instead of to detect the whole light’s intensity. The second is that both of the two orthogonally polarized lights of a birefringent dual frequency laser are fed back. The third one is that only one of the orthogonally polarized lights is fed back. The experimental results show that the modes competition between orthogonally polarized lights can be used to improve the vertical resolution of laser optical feedback microscope effectively.关键词：laser optical feedback;vertical resolution;modes competition;microscope- 54
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发布时间：2020-08-12 -
Manufacturing and testing of X-ray imaging components with high precision
摘要：In the latest 20 years, X-ray imaging technology has developed rapidly in order to meet the needs of X-ray photo-etching,spatial exploration technology, high-energy physics, procedure diagnosis of ICF,etc. Since refractive indices of materials in the X-ray region are lower than 1, and X-ray is strongly absorbed by materials, the characteristics of X-ray increase greatly difficulty to obtain X-ray image. Conventional imaging methods are hardly suitable to X-ray range. In general, grazing reflective imaging and coding aperture imaging methods have been adopted more and more.We have designed a non-coaxial grazing reflective X-ray microscope which is composed of four spherical mirrors, in order to satisfy the requirement of the diagnosis of inertial confinement fusion (ICF). The four mirrors have the same radius of curvature. The radius of each mirror is 29 000 mm and the aperture is 30 mm×15 mm. Allowable tolerance of the radius is ≤0.2% and one of surface roughness (rms) is ≤0.6 nm. Evidently it is very difficult to fabricate and test such mirrors. In order to obtain eligible mirrors, we choose 18 mirror roughcasts and array them on a round disk according to format. The combined manufacturing method can ensure high accordant quality. The fabricated mirrors are tested by both templet and double round aperture methods. Radius errors of the mirrors is about 53 mm. The surface roughness (rms) of the mirrors is inspected by the relative interferometric equipment (WYKO) and atomic force microscope. Before and after coating the measured surface roughness is averagely 0.52 nm and 0.4 nm, respectively.关键词：X-ray imaging;quality evaluation;manufacturing and testing;nanometer precision;nanometer component- 55
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发布时间：2020-08-12
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