ADSL实用化需注意的问题

（１）铜线性能对ＡＤＳＬ传输距离和质量有很大影响，其实际应用传输距离视线路质量和传输码速而定。市话用户铜线有直流特性和交流特性。直流特性包括环阻、线间绝缘、对地绝缘、不平衡电阻;交流特性有频率衰耗特性、阻抗、近（远）端串音、杂音、反射衰耗等。这些特性?..     

内馈电机斩波控制调速技术在水行业中的应用

本文介绍了内馈电机斩波控制调速技术的原理及其在两家自来水厂的应用和节能分析。     

智慧城市信息通信系统研究

总结了智慧城市的特征以及智慧城市信息通信系统中用到的关键技术。分析了智慧城市信息通信系统的架构,以及各个层次的解决方案。最后提出了智慧城市信息通信系统研究、建设中需要关注的问题。     

Fabrication and investigation of ferroelectric memristors with various synaptic plasticities

In the post-Moore era, neuromorphic computing has been mainly focused on breaking the von Neumann bottlenecks. Memristors have been proposed as a key part of neuromorphic computing architectures, and can be used to emulate the synaptic plasticities of the human brain. Ferroelectric memristors represent a breakthrough for memristive devices on account of their reliable nonvolatile storage, low write/read latency and tunable conductive states. However, among the reported ferroelectric memristors, the mechanisms of resistive switching are still under debate. In addition, there needs to be more research on emulation of the brain synapses using ferroelectric memristors. Herein, Cu/PbZr_0.52Ti_0.48O₃ (PZT)/Pt ferroelectric memristors have been fabricated. The devices are able to realize the transformation from threshold switching behavior to resistive switching behavior. The synaptic plasticities, including excitatory post-synaptic current, paired-pulse facilitation, paired-pulse depression and spike time-dependent plasticity, have been mimicked by the PZT devices. Furthermore, the mechanisms of PZT devices have been investigated by first-principles calculations based on the interface barrier and conductive filament models. This work may contribute to the application of ferroelectric memristors in neuromorphic computing systems.     

OADM的技术和应用

介绍了OADM的两种类型,包括各类OADM中采用的关键技术及其在光传送网中的应用特点。     

使用SiNx原位淀积方法生长的GaN外延膜中的应力研究

采用低压MOCVD系统,在生长过程中使用SiNx原位淀积的方法产生纳米掩模,并在纳米掩模上进行选区生长和侧向外延制备了GaN外延薄膜.使用拉曼光谱和光荧光的手段对GaN外延膜中的残余应力进行了研究.研究发现,用SiNx原位淀积出纳米掩模后,GaN生长将由二维向三维转变,直到完全合并为止.利用拉曼光谱和光荧光谱分别研究了薄膜中的残余应力,两者符合得很好;这种方法生长出的GaN薄膜的应力分布较传统的侧向外延更加均匀;并且从中发现随着生长过程中SiNx原位淀积时间的增加,生长在其上的GaN外延膜中的残余应力减小.这是因为,随着SiNx原位淀积时间的增加,SiNx纳米掩模的覆盖度也增大.因此侧向外延区的比例增大,残余应力随之减小.     

多线程异步I/O模型

提出了一种基于WIN32的多线程异步I／O模型,用于解决复杂的多路并发I／O问题,并说明了该模型的运行机制及优越性。     

用于降低高速CMOS图像传感器电荷转移时间的工艺技术

This paper proposes pixel process techniques to reduce the charge transfer time in high speed CMOS image sensors.These techniques increase the lateral conductivity of the photo-generated carriers in a pinned photodiode(PPD) and the voltage difference between the PPD and the floating diffusion(FD) node by controlling and optimizing the N doping concentration in the PPD and the threshold voltage of the reset transistor,respectively.The techniques shorten the charge transfer time from the PPD diode to the FD node effectively.The proposed process techniques do not need extra masks and do not cause harm to the fill factor.A sub array of 3264 pixels was designed and implemented in the 0.18 m CIS process with five implantation conditions splitting the N region in the PPD.The simulation and measured results demonstrate that the charge transfer time can be decreased by using the proposed techniques.Comparing the charge transfer time of the pixel with the different implantation conditions of the N region,the charge transfer time of 0.32 s is achieved and 31% of image lag was reduced by using the proposed process techniques.     

Electroluminescence of an n-ZnO/p-GaN Heterojunction under Forward and Reverse Biases

Electroluminescent characteristics of n-ZnO/p-GaN heterojunctions under forward and reverse biases are studied. Emissions at 389nm and 57Ohm are observed under forward bias. An unusual emission at 390ram appears under reverse bias, and is attributed to the recombination in the p-GaN side of the heterojunction. The yellow emission peaked at 57Ohm is suppressed under reverse bias. The light intensity exponentially depends on the reverse current. The emission under reverse bias is correlated to tunnelling carrier transport in the heterostructure. Our results also support that the well-known yellow band of GaN comes from the transitions between some near-conduction-band-edge states and deep localized acceptor states.     

Passively Q-Switched Nd:YVO_4 Laser Using a Gold Nanotriangle Saturable Absorber

A passively Q-switched Nd:YVO_4 laser at 1064 nm is demonstrated based on a gold nanotriangle saturable absorber(GNT SA).Under a pump power of 3.82 W,the maximum average output power of 218mW is achieved,corresponding to a slope efficiency of 12.9%.The minimum pulse width is 165ns and the maximum pulse repetition rate is 300kHz at the pump power of 3.48 W.Our results prove that the GNT SA is a promising saturable absorber for near-infrared lasers.