最新刊期
卷 32 ， 期 1 ， 2024
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Thin-layer control error analysis and performance optimization of visible light anti-reflection film
摘要：To improve the imaging quality of optical lenses and eliminate the influence of stray light， an antireflective film with an average reflectance of less than 0.1% in the visible wavelength range was designed on a K9 glass substrate. Using electron beam evaporation as the preparation method， to address the issues of high sensitivity and large spectral changes in thin films， a mathematical model was established to stabilize the control of film thickness， reduce film thickness errors， improve preparation accuracy， and film formation stability. Environmental testing experiments were conducted on the antireflective film， in which the process parameters were continuously optimized and adjusted， with a focus on improving the hardness and water boiling resistance of the antireflective film. The experimental results show that the average reflectance of the prepared antireflective film is approximately 0.044% and the highest reflectance is 0.071 2% in the band range of 420-680 nm. Thus， problems caused by the poor mechanical properties and chemical stability of the antireflective film with MgF2 as the outer layer are overcome. Further， the developed film meets the requirements of low loss， stability， reliability， high strength， and repeatable preparation in engineering applications.关键词：thin film;electron beam evaporation coating;error control;mechanical properties;visible light;Reflectance- 439
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发布时间：2024-01-13 - 摘要：High-quality ghost imaging （GI） at low sampling rate is of great importance for scientific research and practical applications. Therefore， the reconstruction of high-quality images under low sampling rate conditions remains the focus of GI research. In this paper， a high-quality passive compressive ghost image reconstruction algorithm was proposed， called PCGI-LRC. Based on the assumption that the matrices stacked with nonlocal similar blocks of an image have low-rank and sparse singular values， a joint iterative solution of the least squares problem was demonstrated theoretically and experimentally and the low-rank approximation problem of the nonlocal similar blocks can achieve high-quality ghost images under low sampling rate conditions （6.25%-50%）. Moreover， the experimental results show that the proposed algorithm outperforms the GI based on sparse basis constraints （GI-SBC） and GI based on full variational constraints （GI-TVC） algorithms regarding peak signal-to-noise ratio （PSNR）， structural similarity coefficient （SSIM）， and visual observation. Information of the target is preserved while the reconstruction noise is suppressed； the PSNR is improved by more than 1.1 dB and the SSIM improvement is higher than 0.04 dB.关键词：ghost imaging;image reconstruction;image suppression;single pixel imaging
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发布时间：2024-01-13 - 摘要：A method for detecting electrospinning jets using coaxial laser assistance is proposed to address the challenges of small diameter， high speed， and difficult detection of electrospinning jets. Based on the principle of optical waveguide transmission， laser is transmitted through optical fibers to the exit of a coaxial needle and coupled with an electrospinning jet， which effectively enhances the contrast between the jet and the background. Combined with the image-processing technology， the evolutions of laser- and nonlaser-assisted electrospinning jet images were compared and analyzed. Based on this analysis， the optimal power range of the auxiliary laser was determined. The experimental results show that coaxial laser assistance can enhance jet detectability， and the most suitable laser power for jet detection is 4 mW. In the jet stabilization stage， the average visible lengths of the electrospinning jet with and without light assistance are 10.79 and 5.68 mm， respectively. Compared with nonlight assistance， the visible length of the electrospinning jet increased by 89.81% on average. For a small jet， the visible lengths of the jet with and without light assistance are 5.36 and 3.33 mm， respectively. The visual length of the jet with light assistance increased by 60.74%. Therefore， the introduction of coaxial laser can effectively improve the detectability of electrospinning jets and is a novel approach to the real-time detection for micro/nanospray printing jets.关键词：electrospinning;coaxial laser;laser assisted;jet detection
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发布时间：2024-01-13 - 摘要：Possible errors in baseline length and angle measurements are qualitatively and quantitatively analyzed to reduce errors in the dynamic monitoring of baseline measurements of the dual-antenna InSAR system that affect the baseline measurement accuracy. First， by establishing a systematic error model， the error source of the measurement system was identified. The error sensitivity was introduced to quantitatively estimate the error term and conduct sensitivity analysis of the error term for each degree of freedom， further generating quantitative synthesis results of the comprehensive error. A set of accuracy inversion error assignment cases was analyzed. The Monte Carlo method was used to verify the feasibility and robustness of the proposed method for accurate quantitative analysis allocation in a simulation closed-loop. The simulation analysis results show that when the accuracy of the position measurements is 300 μm （3σ）， and the accuracy of the triaxial angle measurements is 50'' （3σ）， the baseline length accuracy can reach 1 mm （1.6σ）， and the baseline angle accuracy is 2″ （1.6σ）. By using this method， the accuracy of baseline measurements can be obtained directly from the input of the measured environmental conditions. The inversion of the error assignments according to the sensitivity coefficient yields the optimal layout of the system. The results are valuable for effectively guiding scheme designs and analyzing the error distribution of the measurement system.关键词：interferometric synthetic aperture radar（InSAR）;baseline measurement;error model;sensitivity analysis
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发布时间：2024-01-13
Modern Applied Optics
- 摘要：During microlens array（MLA） photolithography exposure process， the number of photolithography points is considerably large， thus， judgement of the photolithography quality by human eyes with a high-magnification microscope is time-consuming and labor-intensive， resulting in high process cost. To solve this problem， an easily detected circular pattern was designed and a Yolov5 model for target detection in deep learning was introduced， which can replace manual eye inspection to a certain extent and complete the rapid judgement of photolithography quality. Based on the proposed method， the optimal interval of the level of energy density during laser scanning and the profile dip angle of the photoresist were analyzed under different photoresist thicknesses. At the same level of energy density during laser scanning， the distortion of photolithography pattern was judged considering circularity. Further， the photoresist thickness， laser power， and processing platform moving speed were selected as independent variables in the MLA photolithography process to evaluate processing quality parameters processing quality parameters， such as photolithography qualification rate， photoresist profile inclination angle， and photolithography circularity， is of great significance for engineering.关键词：maskless lithogrophy;microlens array;qualification rate;object detection
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发布时间：2024-01-13 - 摘要：As the probe alignment error influences measurement results of tooth profile deviations of arc cylindrical worms （ZC worm） on the gear measuring center， a probe alignment error correction method should be established. Based on the equation of toroidal enveloping cylindrical worm （ZC1 worm） tooth flank and the probe alignment error， an axial profile measurement error model for the ZC1 worm is established to correct the axial coordinates of the tooth profile measurement points. Then， the worm axial profile deviations were evaluated according to the accuracy standards. The effects of varying thread number， module， and reference circle diameter on the tooth profile measurement error were analyzed. The experimental results show that the probe alignment error has little effect on the tooth profile form deviation， while the maximum difference between the total profile deviations before and after the probe alignment error correction reduced from 1.2 μm to 0.2 μm； that between the profile form deviation measurements reduced from 0.5 μm to 0.3 μm； and that between the profile slope deviations reduced from 2.5 to 0.4 μm. The proposed probe alignment error correction method can effectively reduce the effect of probe alignment errors on worm profile deviation measurements of gear measurement centers.关键词：precision measurement;ZC worm;probe alignment;error correction;gear measurement center
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发布时间：2024-01-13 - 摘要：Aiming at the multidimensional， extensive range， and precision positioning requirements regarding micromanipulation and micro-assembly tasks， two degree-of-freedom （DOF） parallel positioning platforms with large strokes and no coupling are designed. A bridge-type mechanism was adopted to amplify the displacement of the built-in piezoelectric actuator， and combined with a composite decoupling structure to form a two-dimensional compliant driving mechanism. Crossed roller guides connected the moving stage with the driving mechanism and adjust the contact friction via preload screws， thus good stick-slip motion characteristics were realized. Then， a finite element method was used to establish the static model of the positioning stage， and the displacement amplification， stress， and inherent frequency were simulated and analyzed. Finally， an experimental test system was built to verify the output performance of the positioning platform. The results show that in the scanning drive mode， when the driving voltage is 150 V， the output displacements of the platform in the x- and y- directions are 63.84 and 62.61 μm， respectively. Further， the coupling ratios are 0.52% and 0.59%， and resolutions are 6.5 nm and 7.2 nm， respectively. In the stepping drive mode， when the driving voltage is 120 V， the single-step displacements of the platform in the x- and y- directions correspond to 47.31 and 47.20 μm， respectively. In addition， the coupling ratios are 0.69% and 0.73%； motion resolutions in x-forward， x-reverse， y-forward， and y-reverse are 0.49， 0.47， 0.47， and 0.42 μm， respectively； and the maximum vertical load is 50 N. The designed piezoelectric stick-slip positioning platform thus meets the required performance requirements.关键词：piezoelectric actuation;bridge mechanism;stick-slip motion;positioning platform
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发布时间：2024-01-13 - 摘要：To improve the environmental adaptability of a piezoelectric vibration energy harvester， a magnetically-coupled tunable piezoelectric vibration energy harvester （PVEH） is proposed. The coupling action between the active magnet on the actuator and the passive magnet on the combined transducer and transversal spring was used to realize the unidirectional limiting excitation of the piezoelectric vibrator. Through modeling and simulation analyses of the energy harvester and magnetic pair， influences of the structural parameters of the energy harvester on the corresponding output performance could be determined. On this basis， the energy harvester prototype was developed by selecting a better magnet diameter via experimental research. The influence laws of the energy harvester's longitudinal mass m1， transversal mass m2， transversal magnet spacing Lx， longitudinal magnet spacing Ly， vertical magnet spacing Lz， and load resistance on the output performance were also obtained. The results show that two order resonant frequencies f1 and f2 cause the output voltage to peak to Un1 and Un2， respectively. Moreover， adjusting m1， m2， Lx， Ly， and Lz will affect f1， f2， Un1， and Un2. Therefore， the effective frequency band and output voltage of the energy harvester can be increased when appropriate structural parameters are selected for the energy harvester. When other conditions are given， there is an optimal load resistance of 2 200 kΩ that increases the output power to 0.122 mW. Therefore， the effective frequency band and output voltage of the energy harvester can be improved by selecting suitable structural parameters and distance between magnets. The results provide good reference value for enhancing the reliability and frequency adaptability of the PVEH.关键词：piezoelectric;adjustable frequency;magnetic coupling;combination transducer;energy recovery
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发布时间：2024-01-13 - 摘要：Yttrium aluminum garnet （YAG） crystals are widely used for manufacturing solid-state lasers， and ultraprecision grinding is critical for machining hard and brittle material parts， such as YAG crystals. The investigation of microdeformation and brittle-to-ductile transition mechanisms of hard and brittle material-machined surfaces is necessary for ultraprecision grinding. Based on the elastic-plastic contact theory and indentation fracture mechanics， a model for predicting the critical depth of brittle-to-ductile transitions was established to achieve low-damage grinding of YAG crystals and obtain high-quality surfaces. The deformation process of the material surface under the action of a single abrasive scratch was analyzed， considering the elastic recovery of the material and the size effect of micromechanical properties. The critical depth of the brittle-to-ductile transition of the YAG crystal is 66.7 nm. The proposed prediction model of the critical depth of the brittle-to-ductile transition was verified by ultraprecision grinding of YAG crystals with grinding wheels of different grain sizes. In addition， the grit-cutting depths of different grain-size grinding wheels under the corresponding process conditions were calculated. The results show that when the grit-cutting depth is more extended than the critical depth of the brittle-to-ductile transition， the surface material of the YAG crystal is removed in a brittle manner， and the grinding surface is severely damaged. However， when the grit-cutting depth is less than the critical depth of the brittle-to-ductile transition， the grinding surface material is removed in a ductile manner， high-quality grinding surface can be obtained， and the machined surface roughness can reach 1 nm. The proposed model for predicting the critical depth of the brittle-to-ductile transition provides theoretical guidance for low-damage ultraprecision grinding of YAG crystals.关键词：YAG crystal;nano-indentation;nano-scratch;brittle-to-ductile transition;ultra-precision grinding
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发布时间：2024-01-13 - 摘要：To reduce the volume of ships， aircraft， and other engines， oblique pipe welding is used instead of elbow connection， and the end position in the pipeline system plays an important role in the welding alignment. First， the pipe axis was obtained by determining the seed cylinder and designing a nonlinear optimization algorithm. Then， the pipeline axis was obtained through diffusion reconstruction of the high-precision seed cylinder. Following this， the pipe edge was searched using the double curvature threshold search method， and the whole pixel coordinates of the end-face edge point of the pipe were obtained. Next， the subpixel coordinates of the end-face edge were obtained via elliptic fitting of the whole pixel coordinates extracted from the end face combined with the ray intersection method， avoiding the effect of the ambient light source on the subpixel coordinates calculated using the interpolation method. Finally， the spatial projection plane was reconstructed using the point-by-point least squares method and the minimal residual spatial ellipse was realized on the plane. The center of the elliptical circle of the space was the end of the pipe， and the projection plane was the plane where the end face was located， enabling accurate measurement of the head position. The experimental results show that the measurement accuracy of this method reaches 0.05 mm， and the angle measurement error is less than 0.1°， basically meeting the accuracy requirements of the head position measurement of an inclined pipeline， and presenting good guiding significance for the assembly of such pipelines.关键词：spatial projection plane;pipeline;endpoint pose measurement;end face reconstruction
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发布时间：2024-01-13
Micro/Nano Technology and Fine Mechanics
- 摘要：The large field optical telescope is an important equipment for the search of medium-high orbit targets. However， stellar targets also appear in the search images. Thus， the identification and suppression of stellar targets is a necessary step in the detection of medium-high orbit targets. Considering the influence of the sky area near the galactic plane， difference in exposure time， and cloudy occlusion， the variation in the star field density within the image is very large. The traditional star identification method has limitations in the calculation accuracy and real-time performance， which leads to the occurrence of false alarm of stars and calculation timeout. To solve these problems， this study proposes a method of star identification and suppression based on the relative invariance of inertia coordinates in time domain. First， the mathematical transformation relationship between the horizon coordinate system and the inertial coordinate system is derived， and the star identification model is constructed accordingly. Then， the time domain relative invariance of the inertial coordinates of the stellar target is quantitatively analyzed under different static system errors. Finally， the star identification and suppression algorithm was verified via simulation and experiment. As a result， the maximum relative difference in the inertial coordinates of stars is 0.51" （right longitude） and 0.16" （declination） when the time interval is 10" and the static system error is 10". Thus， the time domain relative invariance meets the requirements regarding star identification， and the corresponding process is completely independent of star field density. The proposed method was also verified considering 100 measurement images of medium-altitude orbit objects， and no false alarm of stars and missing detection phenomenon of medium-altitude orbit objects were observed.关键词：target detection;identification and suppression of stars;search of GEO and MEO;inertial coordinate system
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发布时间：2024-01-13 - 摘要：A detection method integrating visual saliency and group decision making was proposed with the aim of achieving efficient and high-precision detection of hole features in aircraft parts in complex environments. First， an image enhancement step was incorporated into the classical frequency-tuned （FT） saliency detection algorithm， and each pixel was assigned a weight based on the center of the maximum saliency region. This improved method was used for hole region segmentation. Second， a novel mathematical morphological edge detection algorithm with multi-scale and multi-structural elements was designed. This algorithm was combined with contour thinning to extract hole contours. Finally， the centroid positions of the contour points were obtained using the Meanshift algorithm and a new model based on group decision making was established for calculating the hole radius， thus obtaining key geometric parameters of the hole features. The results show that the improved visual saliency feature detection algorithm generates higher-resolution saliency maps that highlight hole features more prominently. This novel mathematical morphological edge detection algorithm obtains simplified and reliable contour points. It also exhibits a high robustness under complex conditions， including uneven lighting， various types of hole defects， and interference from the hole interior. This method can still perform hole detection successfully even with a noise density of up to 30%， and the errors in the coordinates of the center and the radius are less than 0.012 mm. The average detection time is only 0.236 s. It can accurately and robustly detect hole features in aircraft parts in complex environments.关键词：aircraft part;hole feature detection;saliency detection;mathematical morphology;group decision making
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发布时间：2024-01-13
Information Sciences
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176855 Email：gxjmgc@ciomp.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
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