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HFC网络中上行信道三种协议的比较 总被引:1,自引:0,他引:1
讨论了基于HFC(混合光纤同轴电缆)网络上行多址接入信道的数据通信,比较了几种适于HFC中MAC(媒体输入控制)层上行数据流的协议,包括分布式协议R-ALOHA,集中式协议U-niLNK以及一种新的协议PCUP(流水线循环上行流协议)最后得出PCUP协议比较适合HFC网中的双向交互式业务的结论。 相似文献
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本文引入了功率电子学计算机辅助分析与设计(CAD/CAA)中的一种分等级建模与仿真方法,以高功率因数交流-直流(AC-DC)变换器对对象,综合几种建模技术,并借助通用电路分析软件包PSPICE,实现了三种等级的建模与仿真。结果表明,它是一种实用而有效的功率电子电路分析和设计方案。 相似文献
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本文引入了功率电子学计算机辅助分析与设计(CAD/CAA)中的一种分等级建模与仿真方法.以高功率因数交流一直流(AC-DC)变换器为对象,综合几种建模技术,并借助通用电路分析软件包PSPICE,实现了三种等级的建模与仿真.结果表明,它是一种实用而有效的功率电子电路分析和设计方案. 相似文献
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本文分析了正交频分复用(OFDM)-码分多址(CDMA)技术的特点,介绍了几种具体的应用方案,并指出OFDM-CDMA技术是适合于高速、大容量数字移动通信系统的一种较佳技术。 相似文献
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分析了微带天线RCS(雷达散射截面)缩减的物理机制,对典型的RCS缩减技术进行了综述,评论了几种计算微带天线RCS的理论方法,指出了微带天线RCS研究中值得探索的若干问题。 相似文献
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转速控制方式光盘的转速控制方式主要有CAV(恒定角速度)、CLV(恒定线速度)、ZCLV(分区恒定线速度)等几种,这些转速控制方式,都同光盘的记录格式有密切关系。CAV方式,其主轴电机的转速相对于整个光盘都是恒定的,记录重放频率也是恒定的。这种方式由... 相似文献
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CMP平坦化工艺技术的发展应用与设备前景 总被引:3,自引:1,他引:2
谢中生 《电子工业专用设备》1997,26(1):12-14
简要介绍化学机械抛光(CMP)的发展应用、美国半导体工业协会蓝图目标,以及几种CMP工艺设备市场预测 相似文献
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介绍数字传输链路的误码性能指标、检测分类及方法,重点阐述并比较了在线测试中的循环冗余校验(CRC)、帧同步码校验、奇偶(P码)校验,以及编码规律破坏校验,最后介绍了几种2Mb/s在线测试仪表 相似文献
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半导体材料研究的新进展 总被引:7,自引:0,他引:7
首先对作为现代信息社会的核心和基础的半导体材料在国民经济建设、社会可持续发展以及国家安全中的战略地位和作用进行了分析,进而介绍几种重要半导体材料如,硅材料、GaAs和InP单晶材料、半导体超晶格和量子阱材料、一维量子线、零维量子点半导体微结构材料、宽带隙半导体材料、光学微腔和光子晶体材料、量子比特构造和量子计算机用材料等目前达到的水平和器件应用概况及其发展趋势作了概述.最后,提出了发展我国半导体材料的建议.本文未涉及II-VI族宽禁带与II-VI族窄禁带红外半导体材料、高效太阳电池材料Cu(In,Ga)Se.CuIn(Se,S)等以及发展迅速的有机半导体材料等. 相似文献
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Soft polymer materials, which are similar to human tissues, have played critical roles in modern interdisciplinary research. Compared with conventional methods, 3D printing allows rapid prototyping and mass customization and is ideal for processing soft polymer materials. However, 3D printing of soft polymer materials is still in the early stages of development and is facing many challenges including limited printable materials, low printing resolution and speed, and poor functionalities. The present review aims to summarize the ideas to address these challenges. It focuses on three points: 1) how to develop printable materials and make unprintable materials printable, 2) how to choose suitable methods and improve printing resolution, and 3) how to directly construct functional structures/systems with 3D printing. After a brief introduction on this topic, the mainstream 3D printing technologies for printing soft polymer materials are reviewed, with an emphasis on improving printing resolution and speed, choosing suitable printing techniques, developing printable materials, and printing multiple materials. Moreover, the state‐of‐the‐art advancements in multimaterial 3D printing of soft polymer materials are summarized. Furthermore, the revolutions brought about by 3D printing of soft polymer materials for applications similar to biology are highlighted. Finally, viewpoints and future perspectives for this emerging field are discussed. 相似文献
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AWG器件是目前光通信元器件中重要的研究课题,而材料是决定AWG性能的基础。本文主要分析了硅基材料、聚合物和磷化铟基等材料在AWG制作技术中的材料特性与应用特点,同时展示了AWG在光通信领域中的应用前景。 相似文献
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Circularly polarized luminescence (CPL) materials have received increasing attention in recent years. Amongst various CPL materials, circularly polarized phosphorescence (CPP) materials featuring long life-time represent a novel research frontier and exhibit promising applications in various fields. Herein, the state-of-the-art advances of CPP materials are systematically summarized, as classified into transition metal complexes, organic small molecules, polymers, and organic/inorganic hybrid materials. Besides, the recent applications of CPP materials in organic light-emitting diodes and encryption display are also summarized. Furthermore, the current challenges and future perspectives are put forward. It is expected that this review will offer more inspirations for the future rational design of advanced CPP materials, thus further promoting their future practical applications. 相似文献
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Hae Un Kim Taehyun Kim Chanhyuk Kim Minjun Kim Taiho Park 《Advanced functional materials》2023,33(1):2208082
Organic light-emitting materials in the near-infrared (NIR) region are important to realize next-generation lightweight and wearable applications in bioimaging, photodynamic therapy, and telecommunications. Inorganic and organometallic light-emitting materials are expensive and toxic; thus, the development of purely organic light-emitting materials is essential. However, the development of highly efficient NIR light-emitting materials made of organic materials is still in its infancy. Therefore, this review outlines molecular design strategies for developing organic small-molecule NIR light-emitting materials with high emission efficiency that can overcome the energy-gap law to be applied to next-generation wearable devices. After briefly reviewing the basic knowledge required for the NIR emission of organic molecules, representative high-efficiency molecules reported over the past 5 years are classified according to their core moieties, and their molecular design, physical properties, and luminescence characteristics are analyzed. Further, the perspective and outlook regarding the development of next-generation high-efficiency NIR organic light-emitting materials are provided. 相似文献