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211.
Zhaoyan Zhang 《Numerical Heat Transfer, Part A: Applications》2013,63(5):497-509
A numerical study of the short-pulsed laser-induced evaporation process is presented. For short-pulsed laser operation, the radiation penetration depths of most nonmetallic engineering materials are of the same order of magnitude as or of higher order of magnitude than the heat diffusion depth. Thus, the materials must be treated as semitransparent media during short-pulsed laser material processing. A quasi–one-dimensional model is developed to predict the two-dimensional heat conduction inside the solid. It is assumed that the conduction losses are normal to the surface and the ablation velocity is governed by an Arhennius equation. The model is solved using an integral method. The numerical simulations of the laser processing of ceramics are carried out. The results indicate that the radiation penetration depths of the materials make significant differences in the groove shape, heat losses, and the temperature field during short-pulsed laser operations. 相似文献
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张兆艳 《武汉理工大学学报》1998,(3)
用溶胶-凝胶法在浮法玻璃上镀制了含银的二氧化硅薄膜．用途射电镜、电子衍射和能谱仪研究了薄膜的微观结构和银的结合状态．讨论了镀膜玻璃的光谱特性． 相似文献
216.
Wanwan Li Jiao Liu Jingnan Wei Zhaoyan Yang Chunlei Ren Bingxiang Li 《Advanced functional materials》2023,33(17):2213485
Flexible conductive materials with intrinsic structural characteristics are currently in the spotlight of both fundamental science and advanced technological applications due to their functional preponderances such as the remarkable conductivity, excellent mechanical properties, and tunable physical and chemical properties, and so on. Typically, conductive hydrogel fibers (CHFs) are promising candidates owing to their unique characteristics including light weight, high length-to-diameter ratio, high deformability, and so on. Herein, a comprehensive overview of the cutting-edge advances the CHFs involving the architectural features, function characteristics, fabrication strategies, applications, and perspectives in flexible electronics are provided. The fundamental design principles and fabrication strategies are systematically introduced including the discontinuous fabrication (the capillary polymerization and the draw spinning) and the continuous fabrication (the wet spinning, the microfluidic spinning, 3D printing, and the electrospinning). In addition, their potential applications are crucially emphasized such as flexible energy harvesting devices, flexible energy storage devices, flexible smart sensors, and flexible biomedical electronics. This review concludes with a perspective on the challenges and opportunities of such attractive CHFs, allowing for better understanding of the fundamentals and the development of advanced conductive hydrogel materials. 相似文献
217.
Zhijie Li;Zhaoyan Zhang;Huifan Cheng;Shaoping Qian;Yuenong Liu; 《Polymer Composites》2024,45(12):11447-11458
Polypropylene carbonate (PPC) is a biodegradable polyester with excellent toughness and ductility that may be employed as carbon fixation materials in biomedicine, agriculture, and environmental engineering. However, relatively lower strength and poor dimensional stability hinder its extensive application. In this study, nanofibrillated cellulose (NFC) and chitosan (CS) were introduced as biobased reinforcements into PPC without compromising its biodegradability. Notably, the composites not only had improved strength but also enhanced toughness after the addition of NFC and CS. The tensile strength and Young's modulus were increased by 25% and 58% in the composites with 3 wt% NFC and 2 wt% CS additions compared to pure PPC. Interestingly, the PPC/NFC/CS composites exhibited superior dimensional stability and antibacterial property. Upon the addition of 3 wt% NFC and 2 wt% CS, the composites took 3 s recovering from 0° to 137°. Additionally, NFC and CS contribute to the hydrophilicity of PPC composites. These findings offer valuable insights into experimental data and preparation techniques to the utilization of PPC in engineering fields. 相似文献
218.
有效处理农村有机生活垃圾（rural organic household waste, ROW）对美化农村环境具有重要意义,在对其进行高浓度厌氧发酵时容易出现酸化和氨氮抑制现象,导致系统稳定性差。目前尚缺乏ROW不同共发酵底物和进料总固体（total solids,TS）浓度对厌氧发酵的影响研究。为提高厌氧发酵性能,减少环境保护压力,本文对ROW不同共发酵底物配比和不同进料浓度下厌氧共发酵特性进行研究,从而优化农村有机生活垃圾厌氧发酵工艺。文中对取自江苏徐州沛县的农村有机生活垃圾和江苏省农业科学院六合动物实验基地的猪粪（PM）、水稻秸秆（RC）进行厌氧共发酵。当发酵底物为ROW和PM时,甲烷产量随着进料总固体含量TS的升高而增加,最高为257.38mL/g VS;当发酵底物为ROW和RC,或者发酵底物为ROW、PM和RC时,进料TS质量分数从8%增加到12%时,甲烷产量随之增加,最高分别为339.59mL/g VS、322.16mL/g VS,当进料TS质量分数继续升高到15% 时,二者产量均出现降低且均低于其他实验组,分别为231.17mL/g VS、194.67mL/g VS。在本文所设置实验条件下,最优共发酵进料为：发酵底物为ROW和RC,生活垃圾与挥发性固体（VS）质量比为1∶1,进料TS质量分数为12%,甲烷产量为339.59mL/g VS。 相似文献
219.
针对双母线接线的母差保护,在母联死区发生故障时,因无法自动识别母线运行状态,导致故障跳闸缺乏选择性且实际故障母线切除时间长的问题,提出一种快速隔离母联死区故障的母线保护原理。新原理将母联断路器两侧CT同时接入母线保护,通过增加母联间隔比率差动,调整小差差流计算方法,使得故障时母线保护装置可自动识别母联断路器分合状态,并准确辨识故障位置,从而提高母联死区保护故障时故障切除的快速性和选择性。仿真结果表明：该方法实现了故障切除的快速性或最小范围隔离故障,提高了母线设备运行状态的自动化以及母线保护装置的智能化水平。 相似文献
220.
为了更简便地生成白噪声波,并探究生成白噪声波所需控制参数的变化规律,提出一种基于摇板造波机的白噪声波生成方法,研制了相应的转阀控制式摇板造波机实验平台,并建立了造波系统数学模型。通过求解数学模型,得到生成白噪声波所需的控制参数,探讨控制参数变化规律。进一步地,依据所求得的控制参数,开展了白噪声波浪生成实验,通过改变组成波波幅及频率,生成了能量谱密度不同的3种白噪声波。研究结果表明:白噪声波可分解为一系列等波幅不同频率的组成波,且生成白噪声波浪的平均能量谱密度与组成波波幅呈正相关变化。 相似文献