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溶胶-凝胶法制备掺镧钛酸钡薄膜及其光学性质研究 总被引:1,自引:0,他引:1
以硝酸镧、醋酸钡、钛酸四丁酯为原料,采用溶胶一凝胶旋涂法制备掺La的钛酸钡薄膜,研究薄膜的晶体结构、表面形貌、紫外-可见光吸收性能及光学带隙。研究结果表明,纯钛酸钡和掺La钛酸钡薄膜均为单一四方钙钛矿结构,La3+的引入可以使钛酸钡薄膜在可见光区的透过率和光学带隙有一定程度下降,而退火温度对掺镧钛酸钡薄膜光学带隙基本无... 相似文献
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为了确保抑制高速电路中同步开关噪声(SSN)的微波光子晶体(EBG)结构在兼顾带隙特性的同时,还具有良好的信号完整性,采用枝条绕转单元贴片的方法设计出一种新型EBG结构。利用HFSS软件对新型EBG结构抑制SSN的特性进行建模仿真,并制备刻蚀有新型EBG结构的4层印制电路板,用安捷伦矢量网络分析仪对其禁带特性进行测试,实验结果与仿真结果吻合良好。通过眼图对新型EBG结构进行的仿真分析显示,新结构的信号完整性良好。 相似文献
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Dongsheng Xie Yue Zhang Xiyue Yuan Youle Li Fei Huang Yong Cao Chunhui Duan 《Advanced functional materials》2023,33(11):2212601
Semitransparent organic solar cells (ST-OSCs) have attracted increasing attention due to their promising prospect in building-integrated photovoltaics. Generally, efficient ST-OSCs with good average visible transmittance (AVT) can be realized by developing active layer materials with light absorption far from the visible light range. Herein, the development of ultrawide bandgap polymer donors with near-ultraviolet absorption, paired with near-infrared acceptors, is proposed to achieve high-performance ST-OSCs. The key points for the design of ultrawide bandgap polymers include constructing donor–donor type conjugated skeleton, suppressing the quinoidal resonance effect, and minimizing the twist of conjugated skeleton via noncovalent conformational locks. As a proof of concept, a polymer named PBOF with an optical bandgap of 2.20 eV is synthesized, which exhibited largely reduced overlap with the human eye photopic response spectrum and afforded a power conversion efficiency (PCE) of 16.40% in opaque device. As a result, ST-OSCs with a PCE over 10% and an AVT over 30% are achieved without optical modulation. Moreover, colorful ST-OSCs with visual aesthetics can be achieved by tuning the donor/acceptor weight ratio in active layer benefiting from the ultrawide bandgap nature of PBOF. This study demonstrates the great potential of ultrawide bandgap polymers for efficient colorful ST-OSCs. 相似文献
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Isolation enhancement between tightly spaced compact unidirectional patch‐antennas on multilayer EBG surfaces 下载免费PDF全文
In this article, ultracompact unidirectional patch antennas are used in different two‐antenna systems for biomedical applications at 5.2 GHz. Multilayer mushroom type electromagnetic bandgap (EBG) structures are designed as slow‐wave medium to reduce the size of the individual patch antennas to 0.1λ0 by 0.18λ0. Various techniques are investigated herein to improve antenna isolation for an enhanced Multiple‐Input Multiple‐Output (MIMO) performance. First, the coupling between 0.3λ0‐spaced antennas is verified to occur dominantly through radiation and near‐field coupling between the patches rather than through substrate‐bound modes. Second, various configurations are proposed to suppress antenna coupling. These approaches include reorientation of the antennas and employment of parasitic radiators between the patches. A novel design is presented in which a unidirectional parasitic slot radiator on an EBG reflector is inserted between the antennas to decouple them. Measurement results confirm efficacy of these approaches in mitigating antenna coupling by more than 11 dB in the operating bandwidth of the antennas. The compact patch antennas maintain efficiency values of higher than 70%. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:30–38, 2015. 相似文献
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文章利用全矢量平面波法分析了二维三角结构空芯光子晶体光纤平面内和平面外存在的光子带隙的结构图.重点分析了课题组拉制的空芯光子晶体光纤,计算出了存在光子带隙的波长范围,发现在1550nm的光纤通讯窗口也存在光子带隙.通过理论计算这种光纤,发现随着包层的空气填充率、包层与空气孔两介质的相对折射率差的增大,带隙宽度也将随之增大.最后,说明了如何制备宽带隙的光子晶体光纤. 相似文献
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设计了一种改进的带隙基准电压源,通过采用分段电流补偿的方法,实现了低压高精度供电。研究基于TSMC 0.35μm CMOS 3V工艺基础,重点考虑主要工作温度区域输出电压随温度变化的精度问题。仿真结果表明,该电路可提供低至500mV的低压,实现了高阶电流补偿,在-40℃~+100℃温度范围内其温漂系数仅为3.7ppm/℃,在芯片主要工作温度范围内,输出基准电压最大偏差小于8μV,低频时电源抑制比为-70dB。 相似文献
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闭环曲率补偿的低电源电压带隙基准源 总被引:1,自引:0,他引:1
A new low-voltage CMOS bandgap reference (BGR) that achieves high temperature stability is proposed. It feeds back the output voltage to the curvature compensation circuit that constitutes a closed loop circuit to cancel the logarithmic term of voltage VBE. Meanwhile a low voltage amplifier with the 0.5 μm low threshold technology is designed for the BGR. A high temperature stability BGR circuit is fabricated in the CSMC 0.5μm CMOS technology. The measured result shows that the BGR can operate down to 1 V, while the temperature coefficient and line regulation are only 9 ppm/℃ and 1.2 mV/V, respectively. 相似文献