1.3μm自组织InGaAs/InAs/GaAs量子点激光器分子束外延生长

报道了分子束外延生长的1.3μm多层InGaAs/InAs/GaAs自组织量子点及其室温连续激射激光器.室温带边发射峰的半高宽小于35meV,表明量子点大小比较均匀.原子力显微镜图像显示,量子点密度可以控制在(1～7)×1010cm-2范围之内,而面密度处于4×1010cm-2时有良好的光致发光谱性能.含有三到五层1. 3μm量子点的激光器成功实现了室温连续激射.     

一种用于超高频RFID阅读器的正交下变频混频器的分析与设计

分析了共用跨导级的正交下变频混频器的性能,包括电压转换增益、线性度、噪声系数和镜象抑制比,分析表明其在电流开关模式下比传统的Gilbert混频器对具有更好的性能.设计并优化了一个基于共用跨导级结构的用于超高频RFID阅读器的正交下变频混频器.在915MHz频段上,该混频器测得12.5dB的转换增益,10dBm的IIP3 ,58dBm的IIP2和17.6dB的SSB噪声系数.芯片采用0.18μm 1P6M RF CMOS工艺实现,在1.8V的电源电压下仅消耗3mA电流.     

信息安全中的数字水印技术

随着信息网络的日新月异,信息的合法使用和保护成为当前重要的热门话题.文中针对日益引起人们关注的数字水印技术,详细讨论了信息隐藏中数字水印技术的概念、基本特征、通用模型等.总结概括了这种技术的发展以及研究状况,在此基础上,提出进一步发展和研究的方向.     

激光测距机测程指标的拟定及测试方法

根据激光测距机对漫反向目标的测距方程,分析了激光测距机测程与背景噪声之间的关系,并对目前普遍存在的激光测距机测程指标与其实际测程不符的问题进行了深入探讨,最终给出了拟定及测定激光测距机测程的一种新的有效方法。     

IP网络建设中的传输承载模式研究

从传输网络与所承载的IP网络间的关联角度出发,分析了IP网络和光传输网络间的联接模式和典型处理方式,提出了光传输网络接口和通道配置的要求和方法。     

汽车电压调节器低频振荡电路的设计

针对汽车电压调节器,设计了一种受温度和电源电压变化影响很小的低频振荡器。通过采用正温度系数电流和负温度系数电流相互叠加,形成2阶补偿,以更加稳定的电流对电容进行充放电。在该振荡电路中,引入一个简单的参考电压电路,使电容充放电的电压随充放电电流的微小变化而变化,以实现电压对电流变化的补偿,从而更加有效地提高振荡器频率的稳定性。基于CSMC 40VBCD工艺,采用Spectre进行仿真,在5V电源电压、-40℃～160℃温度范围内,其频率最大误差小于0.96%;在4～6V电源电压下,温度为0℃时,其频率最大误差小于1.33%。     

Room-Temperature Mechanical Properties and Slow Crack Growth Behavior of Mg2Si Thermoelectric Materials

Mg₂Si is of interest as a thermoelectric (TE) material in part due to its low materials cost, lack of toxic components, and low mass density. However, harvesting of waste heat subjects TE materials to a range of mechanical and thermal stresses. To understand and model the material??s response to such stresses, the mechanical properties of the TE material must be known. The Mg₂Si specimens included in this study were powder processed and then sintered via pulsed electrical current sintering. The elastic moduli (Young??s modulus, shear modulus, and Poisson??s ratio) were measured using resonant ultrasound spectroscopy, while the hardness and fracture toughness were examined using Vickers indentation. Also, the Vickers indentation crack lengths were measured as a function of time in room air to determine the susceptibility of Mg₂Si to slow crack growth.     

System View与MAX+PLUSⅡ互补作用分析

讨论了在通信实验中广泛应用的两EDA软件,SystemView与MAX+PLUSⅡ,分别论述了它们的特点和设计流程。作为对比,在实例中,分别用这两种软件解决相同通信问题,以期在具体的实现过程中,找到它们的区别与互补之处,从而更好的为通信实验服务。最后提出了对于通信实验应用EDA软件的相关建议。     

A New Strategy to Effectively Suppress the Initial Capacity Fading of Iron Oxides by Reacting with LiBH4

In this work, a new facile and scalable strategy to effectively suppress the initial capacity fading of iron oxides is demonstrated by reacting with lithium borohydride (LiBH₄) to form a B‐containing nanocomposite. Multielement, multiphase B‐containing iron oxide nanocomposites are successfully prepared by ball‐milling Fe₂O₃ with LiBH₄, followed by a thermochemical reaction at 25–350 °C. The resulting products exhibit a remarkably superior electrochemical performance as anode materials for Li‐ion batteries (LIBs), including a high reversible capacity, good rate capability, and long cycling durability. When cycling is conducted at 100 mA g^?1, the sample prepared from Fe₂O₃–0.2LiBH₄ delivers an initial discharge capacity of 1387 mAh g^?1. After 200 cycles, the reversible capacity remains at 1148 mAh g^?1, which is significantly higher than that of pristine Fe₂O₃ (525 mAh g^?1) and Fe₃O₄ (552 mAh g^?1). At 2000 mA g^?1, a reversible capacity as high as 660 mAh g^?1 is obtained for the B‐containing nanocomposite. The remarkably improved electrochemical lithium storage performance can mainly be attributed to the enhanced surface reactivity, increased Li⁺ ion diffusivity, stabilized solid‐electrolyte interphase (SEI) film, and depressed particle pulverization and fracture, as measured by a series of compositional, structural, and electrochemical techniques.     

包含双层半导体和金属纳米晶MOS电容的存储特性

制备了包含双层半导体和金属纳米晶的MOS电容结构,研究了其在非挥发性存储器领域的应用。利用真空电子束蒸发技术,在二氧化硅介质中得到了半导体硅纳米晶和金属镍纳米晶。与包含单层纳米晶的MOS电容相比,这种包含双层异质纳米晶的MOS电容显示出更大的存储能力,且保留性能得到改善。说明顶层的金属纳米晶作为一层额外的电荷俘获层可以通过直接隧穿机制进一步延长保留时间和提高平带电压漂移量。