Fabrication of high-performance InGaAsN ridge waveguide lasers with pulsed anodic oxidation

We have demonstrated high-performance InGaAsN triple-quantum-well ridge waveguide (RWG) lasers fabricated using pulsed anodic oxidation. The lowest threshold current density of 675 A/cm/sup 2/ was obtained from a P-side-down bonded InGaAsN laser, with cavity length of 1600 /spl mu/m and contact ridge width of 10 /spl mu/m. The emission wavelength is 1295.1 nm. The transparency current density from a batch of unbonded InGaAsN RWG lasers was 397 A/cm/sup 2/ (equivalent to 132 A/cm/sup 2/ per well). High characteristic temperature of 138 K was also achieved from the bonded 10/spl times/1600-/spl mu/m/sup 2/ InGaAsN laser.     

改进决策树算法的应用研究

针对ID3算法倾向于取值较多的属性的特点,同时为避免特定领域主观属性影响分类结果,提出了一种改进的决策树算法。该方法利用决策树算法构造决策树,通过对分类结果中主客观属性进行标记并逻辑运算,最终得到较客观的决策信息,并进行实验验证。     

Generation of wavelength-switched optical pulse from a fiber ringlaser with an F-P semiconductor modulator and a HiBi fiber loop mirror

A simple configuration to perform wavelength switching in an actively mode-locked fiber ring laser is demonstrated. A Fabry-Perot laser diode was used as a modulator and a HiBi fiber loop mirror was used as a periodic multichannel wavelength filter in the cavity. By setting the channel spacing of nm can be achieved by tuning the fiber loop mirror filter. In the wavelength-switched process, the modulation frequency was not required to be changed     

Influence of metal layer on the transmitted spectra of SPR-based optical fiber sensor

For the surface plasmon resonance (SPR)-based optical fiber sensor with four-layer configuration (fiber core/metal/sensing layer/sample), the effects of different metals, different models (Lorentz-Drude model and Drude model) for the same metal, the thickness of metal layer, and the refractive index (RI) of sample on the transmitted spectra are investigated. The calculated results show that the real part of the refractive index of metal layer has the greatest effects on the sharp degree of the transmitted dip. Moreover, the dispersion function under four-layer configuration can be used to understand the relationship between the resonance wavelength and the thickness of metal layer.     

A comparative study of self-heating effect of nMOSFETs fabricated on SGOI and SGSOAN substrates

In this work, for the first time, the electrical and thermal characteristics of strained Si/SiGe nanoscale n type metal–oxide–silicon field-effect transistors (MOSFETs) with silicon-on-aluminum nitride (SOAN) substrate are investigated by ISE TCAD. This novel structure is named as SGSOAN nMOSFET. A comparative study of self-heating effect (SHE) of nMOSFETs fabricated on SGOI and SGSOAN are presented in this paper. Numerical study results show that this novel SGSOAN structure can greatly eliminate excessive self-heating in devices, which gives a more promising application for SGOI to work at high temperature.     

A 1.2-V 19.2-mW 10-bit 30-MS/s pipelined ADC in 0.13-μm CMOS

A 10-bit 30-MS/s pipelined analog-to-digital converter(ADC) is presented.For the sake of lower power and area,the pipelined stages are scaled in current and area,and op amps are shared between the successive stages. The ADC is realized in the 0.13-μm 1-poly 8-copper mixed signal CMOS process operating at 1.2-V supply voltage. Design approaches are discussed to overcome the challenges associated with this choice of process and supply voltage, such as limited dynamic range,poor analog characteristic device...     

Multiuser MIMO OFDM Based TDD/TDMA for Next Generation Wireless Communication Systems

Multiple-input multiple-output (MIMO) wireless technology in combination with orthogonal frequency division multiplexing (MIMO OFDM) is an attractive air-interface solution for next-generation wireless local area networks (WLANs), wireless metropolitan area networks (WMANs), and fourth-generation mobile cellular wireless systems. In this paper, one multiuser MIMO OFDM systems with TDD/TDMA was proposed for next-generation wireless mobile communications, i.e., TDD/TDMA 4G, which can avoid or alleviate the specific limitations of existing techniques designed for multiuser MIMO OFDM systems in broadband wireless mobile channel scenarios, i.e., bad performance and extreme complexity of multiuser detectors for rank-deficient multiuser MIMO OFDM systems with CDMA as access modes, extreme challenges of spatial MIMO channel estimators in rank-deficient MIMO OFDM systems, and exponential growth complexity of optimal sub-carrier allocations for OFDMA-based MIMO OFDM systems. Furthermore, inspired from the Steiner channel estimation method in multi-user CDMA uplink wireless channels, we proposed a new design scheme of training sequence in time domain to conduct channel estimation. Training sequences of different transmit antennas can be simply obtained by truncating the circular extension of one basic training sequence, and the pilot matrix assembled by these training sequences is one circular matrix with good reversibility. A novel eigenmode transmission was also given in this paper, and data symbols encoded by space–time codes can be steered to these eigenmodes similar to MIMO wireless communication systems with single-carrier transmission. At the same time,, an improved water-filling scheme was also described for determining the optimal transmit powers for orthogonal eigenmodes. The classical water-filling strategy is firstly adopted to determine the optimal power allocation and correspondent bit numbers for every eigenmode, followed by a residual power reallocation to further determine the additional bit numbers carried by every eigenmode. Compared with classical water-filling schemes, it can also obtain larger throughputs via residual power allocation. At last, three typical implementation schemes of multiuser MIMO OFDM with TDMA, CDMA and OFDMA, i.e., TDD/TDMA 4G, VSF-OFCDM and FuTURE B3G TDD, were tested by numerical simulations. Results indicated that the proposed multiuser MIMO OFDM system schemes with TDD/TDMA, i.e., TDD/TDMA 4G, can achieve comparable system performance and throughputs with low complexity and radio resource overhead to that of DoCoMo MIMO VSF-OFCDM and FuTURE B3G TDD.     

台达机电产品在塑料薄膜生产线上的应用

本文主要介绍了台达机电产品(触摸屏、PLC、变频器、温控器等)在塑料薄膜生产线上的应用。该控制系统结合台达HMI、PLC、和变频器等自动化产品,操作界面友好简单,实现了设备的技术升级与高效节能。系统运行证明:台达产品稳定可靠,控制效率高,值得业界同行借鉴和推广。     

基于工频变压器的独立逆变电源设计

提出一种基于工频变压器的逆变电源设计方案.该控制电路采用U3988控制器,输出PWM波形来控制逆变电路功率管,同时U3988内部具有各种电路保护作用,可使逆变电源数字化,简化电路;与无工频变压器逆变电路相比,该电路设计采用工频变压器起到隔离保护的作用,使电路具有系统可靠性功能.实验结果表明,对于传统逆变器,该设计方案不仅省去额外保护电路使电路结构简单明了,还可以使系统从无法保障稳定性到具有可靠稳定性.     

舰载机有限可修复备件库存模型

为在舰载机可修复备件库存管理中保持合理的库存及必要的订货补充,提出有限可修复备件库存模型。分析舰载机有限可修复备件维修供应模式;基于储存理论,研究连续采购模型,给出适用于Vari-Metric理论的有限可修复备件适用性修改方法;研究有限可修复备件批量采购模型,给出批量采购的最优订购点和最优订购量,并进行实例分析。结果表明：该方法有较高的理论参考价值,对提高舰载机备件供应保障能力具有积极意义。