Characteristics of pressure fluctuations and fine coal preparation in gas-vibro fluidized bed

To improve the separation efficiency of air dense medium fluidized beds for dry coal preparation, a gas-vibro fluidized bed has been proposed in which magnetic powder is used as the heavy medium. Pressure fluctuations in the gas-vibro fluidized bed were investigated using time- and frequency-domain analysis methods. The relationship between pressure fluctuations, bubble behavior, and separation efficiency was established. The low amplitude of the standard deviation, the power spectral density (PSD), the incoherent-output PSD, and the high amplitude of the coherent-output PSD, which corresponds to the bubble behavior in the bed, were improved for coal preparation. The coal ash content was reduced from 42.55% to 16.54% by using the gas-vibro fluidized bed.     

秦山三期核电工程反应堆地段节理裂隙模拟

以秦山三期核电工程反应堆地段作为研究对象 ,针对节理裂隙在岩体中的分布具有随机性的特点 ,运用随机方法对其分布规律进行了研究。根据实测的节理裂隙产状、间距及迹线长度 ,推断节理裂隙概率分布特征。同时充分考虑到节理裂隙分布的不均匀性和方向性等特点 ,采用非平稳态随机过程模拟节理裂隙间距 ,通过 Monte- Carlo方法得到等效的节理裂隙网络。根据统计和拟合的结果 ,对反应堆地段岩体的节理裂隙进行了评价。     

点态化Fuzzy幂群的转移定理

从F uz zy点的角度来研究F uz zy幂群,建立F uz zy幂群的转移定理,然后通过转移定理将分明幂群的许多概念和结论直接转到F uz zy幂群,揭示了F uz zy幂群与分明幂群的关系。     

Advance Technologies in Biodegradable Flexible Solid-State Supercapacitors: A Mini Review on Clean and Sustainable Energy

In the recent times research towards solid state supercapacitors (SSS) have increased drastically due to the promising performance in futuristic technologies particularly in portable and flexible electronics like smart watches, smart fabrics, foldable smartphones and tablets. Also, when compared to supercapacitors using liquid electrolyte, solid electrolyte has several advantages like high energy density, safety, high cycle life, flexible form factor, and less environmental impact. The crucial factor determining the sustainability of a technology is the eco-friendliness since the natural resources are being exploited in a wide scale. Numerous studies have focused on biodegradable materials for supercapacitor electrodes, electrolytes, and other inactive components. Making use of these biodegradable materials to design a SSS enables the technology to sustain for a very long time since biodegradable materials are not only environment friendly but also, they show relatively high performance. This review focuses on recent progress of different biodegradable electrodes, and electrolytes along with their properties, electrochemical performance and biodegradable capabilities for SSS have been analyzed and provides a concise summary enabling readers to understand the importance of biodegradable materials and to narrow down the research in a more rational way.     

Use of ultrasound irradiation during acid etching of the 2024 aluminum alloy: Effect on corrosion resistance after anodization

While aluminum alloys are widely used in industrial applications, their protection by anodization as surface treatment always requires a preparation step by alkaline or acid etching. In this paper, use of ultrasound during the acid etching step on the 2024 aluminum alloy was investigated. Etching rate, calculated as of weight loss, was measured under ultrasound irradiation, and compared to silent conditions. The etched surface was characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS) and X-Ray Diffraction (XRD). Surface treatment was performed up to the final anodization step samples, and their final properties were evaluated as a function of various pre-treatments, including acid etching under ultrasound. The main evaluation concerned anticorrosion properties through electrochemical tests: polarization measurements and electrochemical impedance spectroscopy (EIS) in NaCl solution. Finally, use of ultrasound irradiation during acid preparation induced a beneficial effect on the corrosion performance of the anodic layer.     

波前功率谱密度(PSD)测量滤波器的设计

在采用波前功率谱密度评价大口径光学元件时,由于测得的原始数据受到测量系统引入的各种噪音和外界干扰的作用,会使检测准确度下降.对比引入带通滤波技术,对原始数据的有效滤波,减小带外的噪音分量和频谱混叠现象的影响.分别设计了无限脉冲响应带通滤波器和有限脉冲响应带通滤波器,通过模拟分析比较了两者的性能,得出在波前波前功率谱密度用于评价大口径光学元件的面形质量时,采用有限脉冲响应滤波器可以得到更高的测量准确度.     

Acoustic emission monitoring during laser shock cleaning of silicon wafers

A laser shock cleaning is a new dry cleaning methodology for the effective removal of submicron sized particles from solid surfaces. This technique uses a plasma shock wave produced by laser-induced air breakdown, which has applied to remove nano-scale silica particles from silicon wafer surfaces in this work. In order to characterize the laser shock cleaning process, acoustic waves generated during the shock process are measured in real time by a wide-band microphone and analyzed in the change of process parameters such as laser power density and gas species. It was found that the acoustic intensity is closely correlated with the shock wave intensity. From acoustic analysis, it is seen that acoustic intensity became stronger as incident laser power density increased. In addition, Ar gas has been found to be more effective to enhance the acoustic intensity, which allows higher cleaning performance compared with air or N₂ gas.     

聚合物电解质在染料敏化太阳能电池中的应用进展

染料敏化太阳能电池(DSSC)由于成本低、污染小、制备工艺简单而受到广泛关注。电解质在其中起到桥梁的作用,能促使染料再生、输运空穴,从而完成整个光电循环过程,是DSSC重要的组成部分。本文简要介绍了DSSC的基本结构和工作原理,指出了传统液态电解质存在的问题,综述了近年来以聚合物为基体制备的新型固态聚合物电解质、凝胶聚合物电解质以及多孔聚合物电解质在DSSC中的应用,最后对聚合物电解质在染料敏化太阳能电池中的发展做出了展望。