混沌序列与一类基于移位寄存器的非线性序列的性能比较

混沌序列与一类基于移位寄存器的非线性序列非线性前馈逻辑(Non-Linear Feed-ForwardLogic,NLFFL)序列都具有非线性、宽带类噪声、大的码族、长的周期且容易产生的特性,通过对它们在产生方式、相关性能、多址性能以及抗相关攻击能力等方面进行分析和仿真研究,说明混沌序列与该类非线性序列在性能上总体相当,但对于短周期序列(N1023),混沌序列的抗相关攻击、抗干扰能力更强,因此更具有实用价值。     

Transmission performance of 10-Gb/s 1550-nm transmitters using semiconductor optical amplifiers as booster amplifiers

We have demonstrated the transmission performance of 10-Gb/s transmitters based on LiNbO/sub 3/ modulator using semiconductor optical amplifiers (SOAs) as booster amplifiers. Utilizing the negative chirp converted in SOAs and self-phase modulation induced by high optical power, we can successfully transmit 10-Gb/s optical signals over 80 km through the standard single-mode fiber with the transmitter using SOAs as booster amplifiers. SOAs can be used for booster amplifiers with a careful adjustment of the operating conditions. In order to further understand an SOA's characteristics as a booster amplifier, we model SOAs and other subsystems to verify the experimental results. Based on the good agreement between the experimental and simulation results, we can find the appropriate parameters of input signals for SOAs, such as extinction ratio, rising/falling time, and chirp parameter to maximize output dynamic range and available maximum output power (P/sub o,max/).     

A printer model using signal processing techniques

An accurate printer model that is efficient enough to be used by halftoning algorithms is proposed. The proposed signal processing model (SPM) utilizes a physical model to train adaptive linear combiners (ALCs), after which the average exposure of each subpixel for any input pattern can be calculated using the optimized weight vector. The SPM can be used to model multi-level halftoning and resolution enhancement, as well as traditional halftoning. The SPM is comprised of a single ALC layer followed by a peak-to-average ratio (PAR) correction layer, which serves to produce a PAR of less than 1.5 in the modeled exposure. The PCN (PAR correction network) employs one ALC/pixel and exploits the physics governing the characteristics of exposure in small regions. A relatively small number of training patterns suffices to train the SPM.     

Virtual fine delay line using one-stage inverter delay

A virtual fine delay line (VFDL) using only two ring oscillators and counters can cover a wide frequency operation range clock without adding any additional delay line stage. The proposed ring oscillator can easily make a unit delay as a one-stage inverter. The VFDL achieves fine resolution of less than 60 ps and small circuit area with two clock cycles lock-in time.     

互调干扰信号的特征识别

在复杂电磁信号环境中,实际存在为数不少的互调干扰信号,对这类信号的有效分析识别,是无线电监测工作需要重点关注解决的难题。对互调干扰信号在幅度特征和频谱峰值特征两个方面的特性进行了分析,给出了互调干扰信号识别的思路。     

一种使用一维电磁带隙结构的高性能Ka频段四次谐波混频器

介绍了一种全集成微带四次谐波混频器,该混频器采用了一种新型电磁带隙结构,可获得很低的变频损耗指标.阐述了一般的谐波混频理论,并用谐波平衡软件对整个电路进行优化仿真.实测得到射频在34~36GHz的频带内,固定中频为100MHz,该混频器最小变频损耗7.67dB,最大变频损耗<10dB.     

Inside Front Cover: The Elastic Properties and Plastic Behavior of Two‐Dimensional Polymer Structures Fabricated by Laser Interference Lithography (Adv. Funct. Mater. 10/2006)

The probing of the micromechanical properties within a two‐dimensional polymer structure with sixfold symmetry fabricated via interference lithography reveals a nonuniform spatial distribution in the elastic modulus “imprinted” with an interference pattern in work reported by Tsukruk, Thomas, and co‐workers on p. 1324. The image prepared by M. Lemieux and T. Gorishnyy shows how the interference pattern is formed by three laser beams and is transferred to the solid polymer structure. The elastic and plastic properties within a two‐dimensional polymer (SU8) structure with sixfold symmetry fabricated via interference lithography are presented. There is a nonuniform spatial distribution in the elastic modulus, with a higher elastic modulus obtained for nodes (brightest regions in the laser interference pattern) and a lower elastic modulus for beams (darkest regions in the laser interference pattern) of the photopatterned films. We suggest that such a nonuniformity and unusual plastic behavior are related to the variable material properties “imprinted” by the interference pattern.     

一种新的分布式QoS控制动态资源调配算法

该文提出了一种新的分布式环境下用于QoS控制的基于模糊逻辑的动态资源调配(Fuzzy logic based Dynamic Resource Allocation,FDRA)算法。分布式环境采用集中式带宽代理(Bandwidth Brokers, BB))与分布式BB相结合的控制模式。分布式BB基于滑动窗口和滑动指针机制,在分配资源不足时向集中式BB请求追加资源,在占用资源高于需求一定阈值时滞后释放部分追加资源。追加资源块和释放资源块的大小分别由集中式BB和分布式BB根据当前网络负荷状态,采用模糊逻辑确定。模糊逻辑算法引入新的基于数据源特性的隶属度函数生成方法,提高决策的有效性。仿真结果证明,该文提出的算法性能优于已有文献的算法。     

Holstein 分子晶体模型能带结构的温度依赖性

研究了温度对Holstein分子晶体模型能带结构的影响,结果表明固体的能带宽度和禁带宽度都与电子和热声子相互作用以及热膨胀密切相关.对一维Li原子品格链,在所选定的参数下,1s和2s的能带宽度随着温度的增加而变窄,两带之间的禁带宽度变宽,这些结果与实验结果在定性上是一致的.显然,研究能带结构的温度依赖性对于理解固体的光学和输运性质都是十分重要的.     

High efficiency red phosphorescent organic light-emitting diodes using a spirobenzofluorene type phosphine oxide as a host material

High efficiency red phosphorescent organic light-emitting diodes have been developed using a spirobenzofluorene type phosphine oxide (SPPO2) as a host material. The SPPO2 had a high glass transition temperature of 119 °C and a smooth surface morphology with a surface roughness less than 1 nm. The red device with the SPPO2 as a host showed a quantum efficiency of 14.3% with a current efficiency of 20.4 cd/A.