最新刊期
期 2 ， 2023
- 摘要：The liquid crystal materials used for liquid crystal microwave communication devices are composed of high birefringence liquid crystal compounds， most of which have higher melting points， making the liquid crystal compositions have higher low temperature eutectic points， unfavorable for the development of microwave communication devices. In this paper， eight kinds of fluorinated ethyl triphenyldialkyne liquid crystal compounds were designed and synthesized， and configured them in a certain ratio to form a liquid crystal composition MA with a low-temperature co-melting point around -46 ℃. And we mixed them with several other liquid crystals and tested the dielectric properties of the liquid crystal compositions in the microwave frequency band （11~35 GHz） using the rectangular resonant cavity perturbation method， and obtained a dielectric constant value （Δεr） of 0.954 at 18 GHz， the maximum dielectric loss is （tanδεr max） 0.008 6， which meets the performance requirements of low melting point liquid crystal materials for microwave applications.关键词：triphenylene liquid crystal;low melting point;high birefringence;synthesis;dielectric properties in high frequency
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发布时间：2023-02-10 - 摘要：In recent years， graphene oxide/liquid crystal elastomer composites have received a lot of attention from scientists due to their stable and efficient photothermal properties. However， most researchers have focused on their photothermal response behavior and usage scenario， and have not systematically investigated the effects of the strength of external stimuli and the size of the composites themselves on their response performance. In this paper， graphene oxide/liquid crystal elastic composites with different liquid crystal molecular orientations were prepared by spin-coating a layer of graphene oxide on the prepared liquid crystal film with a fixed orientation， which can achieve the dual stimulation response of infrared light and temperature， and the response performance and deformation law were characterized and analyzed. The experimental results show that the graphene oxide/liquid crystal elastomer composite is an infrared-thermal responsive composite， which shows 2 different deformation laws due to different shearing modes. Based on this， the response properties of the composite under different intensity external field stimulation and the effect of different dimensions of the composite itself on the response properties of the composite are investigated. It is found that the response properties of type 1 composites are mainly affected by the width， and the response properties of type 2 composites are mainly affected by the length， which provides a basis for the application of graphene oxide/liquid crystal elastomer composites. Biomimetic photothermal actuators were prepared by this composite， implying great potential in the field of biomimicry.关键词：liquid crystal elastomer;graphene oxide;reversible deformation;response properties
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发布时间：2023-02-10 - 摘要：New solid-state lighting and display technologies have remarkble advantages of high brightness， high luminescence efficiency and environmentally friendly， which have become a technology with great application prospects for high-end lighting and display in the field of indoor and outdoor lighting， automotive headlights， laser TVs， etc. As the core material for fluorescent conversion lighting and display， the performance of green luminescent material undoubtedly determines the optical behavior of the device. However， under the operation of high-power density laser， the temperature of green luminescent material increases sharply， which leads to the decrease of quantum efficiency and luminescence attenuation， and seriously restricts the application of solid-state lighting and display technology. Therefore， different physical forms of green luminescent material came into being. In this paper， the latest research progress of green luminescent material for laser display is reviewed. The control strategies of the properties of green luminescent material， such as powder， ceramic， glass and film， in term of thermal stability， full width at half maximum（FWHM）， color gamut and chromaticity parameters are summarized systematically. Finally， the challenges of green luminescent material such as luminescence efficiency and device packaging are discussed， and the research progress of green luminescent material for lighting and display is prospected.关键词：Solid state lighting and display;Green luminescent materials;Luminescent thermal stability;Light quality;FWHM
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发布时间：2023-02-10 - 摘要：Liquid crystal display is the representative of semiconductor display technology and also the mainstream display technology at present and in the future. With the rise of 5G， AR/VR and other new markets， the display technology as the carrier of information technology will have a broader space for development. At the same time， the requirements of higher performance in color performance， response rate， flexibility， power consumption and lifetime are getting more and more urgent. The development of display technology depends on the innovation of material system. The systematic innovation of liquid crystal display materials is an important driving force for the innovation and development of display technology. The standardization can regulate market behavior and promote the establishment of the best order. It is an important bridge to promote the transformation of scientific and technological achievements into productive forces and a link to promote trade development. The standardization has played an important role in solidifying the innovative achievements of liquid crystal display materials， improving the quality stability， and normalizing the competition of market. In this paper， the industrial system and standard status of liquid crystal display materials are systematically sorted out， the standard system of liquid crystal display materials is scientifically planned， the ideas and suggestions for the construction of the standard system are given in combination with the problems and trends of the development of liquid crystal display standardization in China.关键词：liquid crystal display;Liquid Crystal Display Materials;Standard;Standard system
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发布时间：2023-02-10
Material Physics
- 摘要：In order to meet the requirements of filtering performance and multi-parameter optimization of liquid crystal tunable filter （LCTF）， an optimal design method of Lyot type LCTF based on the artificial immune algorithm （IA） is proposed in this paper. This method takes the basic spectral performance of Lyot type LCTF such as optical transmittance， full width at half maximum （FWHM） of the transmitted main peak， and sidelobe suppression （SLS） in cut-off region as the evaluation function，which aims to find optimal configuration of liquid crystal cells’ thickness and driving voltages of LCTF based on global range constrained by specific evaluation function. The simulation results show that compared with the traditional Lyot type LCTF， the side lobe suppression effect of the optimized LCTF by IA algorithm is increased by 73.42% and the overall filtering effect is improved by 13.90%. At the same time， this method can realize the intelligent regulation of the filter performance only by adjusting the weight ratio of parameters in the evaluation function to meet the requirements of different application scenarios. The most attractive advantage of this design method is that it can avoid the serious dependence of the traditional filters on the linear accuracy of device thickness. Moreover， it is not only more flexible in selection of liquid crystal cells thickness and numbers， but also can improve the spectral response time and optical transmittance， which ensures the high efficiency，development practicality and economy.关键词：liquid crystal;lyot tunable filter;artificial immune algorithm;optimal design;intelligent regulation
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发布时间：2023-02-10
Device Physics and Device Preparation
- 摘要：This paper demonstrates an AC full color display device with opposite polarities hybrid integrated by micro-LED and OLED， which can make the brightness and light efficiency between different color sub-pixels more uniform. Besides， it has various advantages of high luminous efficiency， long lifetime and high pixel density. In addition， we propose a customized driving scheme for the display devices. The new display device can improve the brightness and light effect inhomogeneity of the traditional single element display devices. The proposed display scheme can solve the driving problem that the traditional driving scheme is not suitable for the reverse parallel structure of AC display devices.关键词：micro-LED;OLED;opposite polarities;display driver
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发布时间：2023-02-10
Driving and Controlling
- 摘要：In order to overcome some defects of traditional methods and the insufficiency of single feature extraction information， while further improving the fusion of infrared and visible images， a method with strong adaptability to different types of features is sought. A non-subsampled contourlet transform （NSCT） infrared-visible image fusion method based on multi-judgment and weighted least squares optimization （WLS） is proposed. Firstly， NSCT is used to decompose the image at multiple scales to obtain the low-frequency and high-frequency subbands of the image. Secondly， the low-frequency sub-band selects local squared entropy and sum-modified laplacian （SML） to complement each other， which extracts a small amount of detailed information under guaranteed good contrast. The high-frequency subbands fully considers the importance of the underlying features， and selects phase consistency （PC）， the local weighted sum-modified Laplacian （WSML） and the local weighted energy （WLE） to complement each other to fuse the detail layer. They are optimized by WLS， and the fused image details are more natural and more suitable for human visual perception. Finally， the inverse transform is performed on the fused low-frequency and high-frequency subbands to obtain a fused image. Through the experimental verification of images with different types of characteristics， experimental results show that the proposed method has subjectively significant targets， clear backgrounds and better visual effects in comparison with other fusion methods. Under the average gradient （AG）， information entropy （IE）， spatial frequency （SF）， and mutual information （MI） of the four objective evaluation indicators， on the premise that MI is relatively good， the other three indicators are in the best position，especially for uniformly illuminated camp images， AG and SF are improved by 6. 9% and 4. 8% in comparison with the best values， thus validating the proposed method effectiveness.关键词：image fusion;multi-judgment;Non-subsampled Contourlet transform;Weighted least squares optimization;human visual perception
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发布时间：2023-02-10 - 摘要：At present， there is little work in the field of dehazing that introduces prior information into data-driven deep learning methods， and most dehazing networks based on deep learning usually have high requirements on computer memory and computing power. To solve the above problems， this paper proposes a multi-scale fusion dehazing network for high-frequency information alignment （HFMS-Net）. The network framework adoptes a cycyle pattern： for the generator， residual connections are introduced at different depths of the lightweight convolutional neural network to make full use of the intermediate layer features of the network to achieve multi-scale feature fusion； for the discriminator， the network needs to extract texture information on its input to approximate the high-frequency information between the dehazed image and the hazy image， making the data-driven network more physically interpretable. Compared with PFDN， HFMS-Net achieves superior performance with about 1/5 of the memory footprint under the same setting， and the PSNR and SSIM are improved by 0.71 and 0.016， respectively. Through a large number of comparative experiments and ablation experiments， it is proved that the dehazing performance of this network has a certain improvement compared with the existing algorithms， and higher fidelity to texture information.关键词：multi-scale fusion;High-Frequency information alignment;Generative Adversarial Networks
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发布时间：2023-02-10 - 摘要：In the imaging process， the remote sensing images are easily affected by clouds and haze weather， and forms foggy images. At the same time， when the data are downloaded， they are affected by various factors （such as transmission and reception errors， signals disturbed by random changes in the ionosphere and troposphere， etc.） making the image information lost or doped with noise. This paper proposes a dehazing algorithm for monochrome remote sensing images based on matrix restoration and dark channel theory for foggy monochrome remote sensing images with information loss. Combined with the matrix restoration based on ADMM（Alternating Direction Method of Multipliers） and dark channel theory， the restoration of remote sensing fog map under the condition of information loss is effectively realized. By combining subjective evaluation and objective evaluation， the algorithm in this paper is compared with the classical algorithm. The results show that the results obtained by the algorithm in this paper are more intuitive and visually effective， and compared with the fog map with 30% information loss， the six scenes have better visual effects. The average information entropy is improved by 1.665 2， the average peak signal-to-noise ratio is improved by 11.702 9， and the average structural similarity is improved by 0.814 6. The objective evaluation index results are excellent. Further experiments are carried out in the case of different proportions of information loss， and the results show that the clear restoration and dehazing image can still be obtained even when a large amount of information is lost.关键词：image dehazing;Monochrome remote sensing image;ADMM;Dark channel theory
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发布时间：2023-02-10 - 摘要：Aiming at the problems of inaccurate segmentation of image target edges and inconsistent segmentation of different types of targets by the DeepLabv3+ model， a semantic segmentation algorithm based on the fusion of class feature attention mechanism is proposed. The algorithm firstly designs a class feature attention module on the encoding end of the DeepLabv3+ model to enhance the correlation between categories， so as to better extract and process semantic information of different categories. Secondly， the multi-level parallel spatial pyramid pooling structure is used to enhance the correlation between spaces so as to better extract contextual information at different scales of images. Finally， at the decoding end， the characteristics of the channel attention module are used to recalibrate the multi-layer fusion features， and the redundant information is suppressed to strengthen the salient features to improve the representation ability of the network. The effectiveness and generalization experiments of the improved model are carried out on the Pascal Voc2012 and Cityscapes datasets， and the average intersection ratios reach 81.34% and 76.27%， respectively.The image edge segmentations in this paper are more detailed， the categories are clearer， and are significantly better than the compared algorithms.关键词：multi-scale feature fusion;Class feature;attention mechanism;semantic segmentation;DeepLabv3+
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发布时间：2023-02-10 - 摘要：Aiming at the problems of unreasonable facial semantic information and inconsistency of facial contours in the restored face image in the deep learning network for face image inpainting， a face image inpainting network guided by face structure information is proposed. Firstly， the encoder-decoder network technology is used to build a face structure sketch generation network， and skip connections and residual blocks with dilated convolution are added to the generator of the structure sketch generation network to generate the structure sketch of the region to be repaired. Secondly， when a face inpainting network is builted， an attention mechanism is introduced into the inpainting network generator， so that the inpainting network pays more attention to the area to be repaired during the inpainting process， and uses the generated face structure sketch as a guide to realize the face image vivid inpainting of facial semantic structure and texture information. Finally， the feature matching loss is introduced into the loss function of the structure sketch generation network for the model training， so as to constrain the generator to generate results more similar to the real structure sketch. In the loss function of the repair network， the perceptual loss and style loss are combined for the model training， therefore， the facial contour structure and color texture of the face image in the area to be repaired can be better reconstructed， so that the repaired image is closer to the real image. The comparative experimental results show that in the face image dataset， the repair performance of the network model designed in this paper has a high improvement.关键词：Face inpating;encoder-decoder;Dilated convolution;Skip connections;attention mechanism
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发布时间：2023-02-10 - 摘要：In the computer vision applications， the tracking algorithms based on the Siamese networks have improved in speed and accuracy compared with the traditional target tracking algorithms， but they are greatly affected by interference factors such as occlusion and deformation. Based on these， the existing target tracking methods and technologies based on Siamese networks are summarized and analyzed， they mainly include the introduction of fully convolutional Siamese neural network method， regression method and online update method in Siamese networks， and the improvements of the target tracking algorithms based on three methods are reviewed. The research progress and development status of Siamese networks in target tracking applications in recent years are introduced in detail. Then， the VOT2017 and LaSOT datasets are used for experimental comparison， and the performances of various tracking algorithms based on Siamese neural networks are compared. At the end， the development trend of the target tracking methods based on Siamese neural networks is prospected.关键词：computer vision;target tracking;siamese networks;deep learning
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发布时间：2023-02-10
Image Processing
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