基于织物结构特征和小波变换的快速疵点检测

给出了一种利用小波为分析工具,基于织物采样图像进行疵点检测的新方法.首先对织物疵点图片进行了奇偶行列采样抽取,得到奇偶两幅子图像并使得图像的总数据变为原来的二分之一,然后再进行小波变换.在进行小波变换时,采用邻域插值,使得紧支撑小波滤波器的系数序列得到缩短,并可以由原来的滤波器系数计算出缩短后的滤波器系数.实验结果表明该方法可以在保证检测效果准确性的同时,大幅减少数据计算量、提升检测速度.     

基于信令降频码方法的信令寻径式光纤交换机的研究

信令寻径式高速光纤交换机需要使用大量"串/并"转换器件提取信令来实现对信道的控制,这使得交换机的底板面积十分庞大,无法检测BGA封装焊接质量;针对以上问题,提出了一种使用特殊的降频码对信令进行编码,成倍地降低信令的频率,采用普通的FPGA器件即可提取信令,取代了大量占线的"串/并"转换器件,减少了PCB面积和降低了成本;并在此基础上给出了高速光纤交换机的解决方案;目前,基于信令降频码方法的信令寻径式光纤交换机已经调试成功,性能稳定,运行状态良好。     

Adaptive robust posture control of a parallel manipulator driven by pneumatic muscles

Rather severe parametric uncertainties and uncertain nonlinearities exist in the dynamic modeling of a parallel manipulator driven by pneumatic muscles. Those uncertainties not only come from the time-varying friction forces and the static force modeling errors of pneumatic muscles but also from the inherent complex nonlinearities and unknown disturbances of the parallel manipulator. In this paper, a discontinuous projection-based adaptive robust control strategy is adopted to compensate for both the parametric uncertainties and uncertain nonlinearities of a three-pneumatic-muscles-driven parallel manipulator to achieve precise posture trajectory tracking control. The resulting controller effectively handles the effects of various parameter variations and the hard-to-model nonlinearities such as the friction forces of the pneumatic muscles. Simulation and experimental results are obtained to illustrate the effectiveness of the proposed adaptive robust controller.     

Amine Coordinated Electron-Rich Palladium Nanoparticles for Electrochemical Hydrogenation of Benzaldehyde

Electrocatalytic hydrogenation (ECH) is a burgeoning strategy for the sustainable utilization of hydrogen. However, how to effectively suppress the competitive hydrogen evolution reaction (HER) is a big challenge to ECH catalysis. In this study, amine (NH₂ R)-coordinated Pd nanoparticles loaded on carbon felt (Pd@CF) as a catalyst is successfully synthesized by a one-step solvothermal reduction method using oleylamine as the reducing agent. An exceptional ECH reactivity on benzaldehyde is achieved on the optimal Pd@CF catalyst in terms of a high conversion (89.7%) and selectivity toward benzyl alcohol (89.8%) at −0.4 V in 60 min. Notably, the Faradaic efficiency for producing benzyl alcohol is up to 90.2%, much higher than that catalyzed by Pd@CF-without N-group (41.1%) and thecommercial Pd/C (20.9%). The excellent ECH performance of Pd@CF can be attributed to the enriched electrons on Pd surface resulted from the introduction of NH₂ R groups, which strengthens both the adsorption of benzaldehyde and the adsorbed hydrogen (H_ads) on Pd, preventing the combination of H_ads to form H₂, that is, inhibiting the HER. This study gives a new insight into design principles of highly efficient electrocatalysts for the hydrogenation of unsaturated aldehydes molecules.     

Privacy Preserving distributed smart grid system based on Hyperledger Fabric and Wireguard

Smart grid has drawn a lot of attention and investment in recent years, which not only helps the modern generation and distribution of traditional power but also highly widens the application of renewable energy sources. However, the main challenges in the application of smart grid are 1. the privacy preservation of users' information and 2. the trustful transmission channel among peers. In order to solve these problems, VPN and blockchain can be considered since they have some features perfectly suitable for these situations. In this paper, we propose a smart grid system based on WireGuard and Hyperledger Fabric to solve the problems mentioned above. And we also implement the whole system and give a view by web application. What's more, all the functionalities are displayed and tested, including building a smart device simulator, deploying data visualization and making some performance evaluations about transactions and WireGuard communication. Experiment results show that the introduction of WireGuard into network infrastructure does not cause too much loss of bandwidth and delay, but it ensures a certain degree of communication security. And Fabric provides the consistency and traceability of transactions in smart grid system.     

Semi-supervised transformable architecture search for feature distillation

Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,...     

Effect of Sintering Temperature on Magnetic and Electrical Properties of GdBaCo<Subscript>2</Subscript><Emphasis Type="Italic">O</Emphasis><Subscript>5 + <Emphasis Type="Italic">δ</Emphasis></Subscript>

In this study, we report the results of an investigation into the sintering temperature dependence of magnetic and transport properties for GdBaCo₂ O _{5 + δ} synthesized through a sol-gel method. The lowering of sintering temperature leads to the increase of oxygen content and the reduction of grain size. The increase of oxygen content results in the enhancement of magnetic interactions and the weakening of Coulomb repulsion effect, while the reduction of grain size improves the magnetoresistance effect. Metal-insulator transition accompanied with spin-state transition is observed in all samples.     

La<Subscript>1−x</Subscript>Ag<Subscript>x</Subscript>FeO<Subscript>3</Subscript>/halloysites nanocomposite with enhanced visible light photocatalytic performance

La_1?xAg_xFeO₃/halloysites nanotubes (HNTs) nanocomposite was synthesized by sol–gel method. It was characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectroscopy and UV–visible diffused reflectance spectroscopy measurements. The photo-activity of the La_1?xAg_xFeO₃/HNTs nanocomposite was evaluated via degradation of methylene blue (MB) under visible-light irradiation. The results showed that the HNTs with unique pore structure favored the adsorption of organic molecules. Adequate Ag⁺ doping improved the absorption ability for visible light. The La_0.95Ag_0.05FeO₃/HNTs demonstrated the best photocatalytic performance, which achieved as high as 99 % for MB degradation exposed 2 h irradiation. However,further increasing of Ag⁺ doping gradually reduced the photocatalytic activity. The nanocomposite catalyst showed outstanding recyclability after eight cycles which still remained up to 90 %.     

超声换能器检测方法的研究

超声检测技术广泛使用在无损检测领域中,而换能器是超声工程中极其重要的技术和分支领域。超声换能器是一种电声能量转换器件,是超声检测技术中的关键,直接影响无损检测结果的可靠性,本文阐述了超声换能器的原理和测量接触换能器的检测方法,分析了A型换能器脉冲回波灵敏度校准的不确定度。