Author Affiliations
Abstract
1 School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
2 Zhuhai Huafa Properties Co., Ltd, Zhuhai 519030, China
Phase-change material (PCM) is widely used in thermal management due to their unique thermal behavior. However, related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level, which results in a gap to real applications. Here, we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material (TRM) based on PCM and reduced graphene oxide (rGO) aerogel to ordinary concrete walls (CWs). The design is evaluated in detail by combining experiments and finite element analysis. It is found that, TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification. The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m2. In addition, the larger the change of thermal conductivity before and after phase change of TRM is, the more effective it is for regulating temperature difference in two directions. The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.
phase change composites controllable thermal rectification building applications Journal of Semiconductors
2024, 45(2): 022301
1 上海理工大学光子芯片研究院,上海 200093
2 上海理工大学光电信息与计算机工程学院,上海 200093
近年来,受生物神经系统结构和功能的启发,神经形态计算引起广泛兴趣。忆阻器可以通过其电荷或磁通量调节电导,与人脑突触作用机制相似,是神经形态计算最有前途的候选器件之一。提出一种基于飞秒激光加工氧化石墨烯基忆阻器的方法,通过调整器件两端扫描电压,实现了极性可控的电阻开关:低电压下,器件表现出单极性电阻开关特性,在150个循环扫描中呈现高度稳定性,且功耗仅有0.75 nW;高电压下,器件呈现双极性开关特性。伴随测试次数的增加,器件整体电导逐步增加,同时分别讨论了两种电压下器件的开关机制。
极性可控 激光加工 氧化石墨烯 忆阻器 激光与光电子学进展
2024, 61(3): 0323002
Author Affiliations
Abstract
1 School of Physics and Optoelectronics and Hunan Institute of Advanced Sensing and Information Technology, Xiangtan University, Xiangtan 411105, China
2 College of Physics and Technology & Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Guilin 541004, China
3 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S10 2TN, UK
4 National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
Palladium (Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics and optoelectronics. However, the synthesis of large-scale uniform PdS and PdS2 nanofilms (NFs) remains an enormous challenge. In this work, 2-inch wafer-scale PdS and PdS2 NFs with excellent stability can be controllably prepared via chemical vapor deposition combined with electron beam evaporation technique. The thickness of the pre-deposited Pd film and the sulfurization temperature are critical for the precise synthesis of PdS and PdS2 NFs. A corresponding growth mechanism has been proposed based on our experimental results and Gibbs free energy calculations. The electrical transport properties of PdS and PdS2 NFs were explored by conductive atomic force microscopy. Our findings have achieved the controllable growth of PdS and PdS2 NFs, which may provide a pathway to facilitate PdS and PdS2 based applications for next-generation high performance optoelectronic devices.
PdS PdS2 nanofilms controllable growth chemical vapor deposition electron beam evaporation Journal of Semiconductors
2023, 44(12): 122001
山西大学资源与环境工程研究所, 国家环境保护废弃资源高效利用重点实验室, 太原 030006
碳酸钙有不同的晶体特征, 使其在各个领域发挥不同的作用, 对碳酸钙晶型、形貌和尺寸的控制是无机材料制备的研究热点。以电石渣为原料制备纳米碳酸钙能够实现变废为宝, 是含钙固废综合利用的研究方向之一。因此在电石渣制备纳米碳酸钙过程中同步实现晶型、形貌的调控, 能够将低附加值的电石渣固废转化为高附加值的纳米碳酸钙产品, 具有良好的环境效应和经济效益。本文总结了电石渣制备纳米碳酸钙的方法, 重点讨论了制备过程中晶型和形貌控制方面的研究进展。结果表明, 在碳酸钙晶体成核和生长的过程中, 控制工艺条件可以通过影响过饱和度进一步实现对晶型和形貌的调控, 且不同种类的添加剂作用机理也不尽相同。热力学、动力学作为控制结晶各过程平衡的基础, 可以用来解释各影响因素的作用机理。
纳米碳酸钙 电石渣 晶型 形貌 可控制备 热力学 动力学 nano calcium carbonate calcium carbide slag crystal structure morphology controllable preparation thermodynamics kinetics
红外与激光工程
2023, 52(2): 20220371
强激光与粒子束
2023, 35(2): 023007
1 武汉大学物理科学与技术学院, 人工微结构教育部重点实验室, 武汉 430072
2 武汉科技大学省部共建耐火材料与冶金国家重点实验室, 武汉 430081
飞秒激光因脉冲持续时间短、峰值功率高、聚焦区域小等特性, 在透明介质中能有效产生多光子非线性吸收选择性改变透明介质内部空间结构, 从而使材料表现出很多优异性能, 近些年备受关注。本文主要以飞秒激光对玻璃的改性为基础, 阐述了飞秒激光诱导析晶及可控定向析晶的基本原理, 综述了近年来利用飞秒激光技术在氧化物玻璃内实现LaBGeO5、LiNbO3和Ba2TiSi2O4等几种典型二阶非线性光学晶体可控析出的研究现状, 分析了其在倍频光波导等领域的应用前景。
二阶非线性 光学晶体 飞秒激光 可控析晶 second-order nonlinear optical crystals femtosecond laser controllable crystallization