具有高速同步功能的12.5Gbps 1:16 解复用器集成电路

A 12.5 Gbps 1:16 demultiplexer (DEMUX) integrated circuit is presented for multi-channel high-speed data transmission. A novel high-speed synchronizing technique is proposed and integrated in this DEMUX chip. Compared with conventional synchronizing techniques, the proposed method largely simplifies the system configuration. The experimental result demonstrates that the proposed circuit is effective in two-channel synchronization under a clock frequency of 12.5 GHz. The circuit is realized using 1 μ m GaAs heterojunction bipolar transistor technology with die area of 2.3 × 2.3 mm².     

Self-assembly deposition and luminescence properties of TiNbO5(-) and TiTaO5(-) nanosheets

Through a novel mechanical cleavage technology, TiNbO5(-) and TiTaO5(-) nanosheets were obtained by the exfoliation of the layered KTiTaO5 and KTiNbO5. Lamellar aggregates of the pre-prepared nanosheets accommodating Eu3+ ions have been fabricated by flocculation of colloidal nanosheet. A series of methods including X-ray diffraction (XRD), transmission electron microscopy (TEM) were used to analyze the structure of the as-obtained composites. The results indicated that the restacking nanosheets could form a uniform layered structure. Meanwhile, the Eu3+ ions could enter into the interlayer of the flocculated nanosheets. The Photoluminescence (PL) spectra were also employed to investigate the optical property of the hybrids. The characteristic emission from the composites either by exciting the nanosheet host with UV light or by directly exciting RE at a longer wavelength were studied in details.     

Luminescence properties of cubic HfO2-Sc2O3:Eu3+ nano-powders

The cubic nano-structured HfO2-Sc2O3:Eu3+ were successfully synthesized via a combustion process. Phase evolution of the synthesized powders was determined by X-ray diffraction measurements. Pure cubic phase of HfO2-Sc2O3 solid solution was obtained after being calcined at 800 degrees C for 2 h.The particle size and morphology were analyzed by TEM. The luminescence properties were also investigated. Photoluminescence spectra of Eu3+ doped HfO2-Sc2O3 nano-powders showed red emission at 613 nm which corresponds to the 5D0-7F2 transition of Eu3+ ion.     

大风地区支柱类设备风振响应研究综述

大风地区支柱类设备大幅风振引起的隔离开关开合困难及疲劳损伤、断裂问题,是目前亟需解决的一种影响变电站(换流站)安全稳定运行的灾害形式。文中根据不同支柱类设备风振破坏特征对变电站风振引起的灾害事故进行了分类。按照支柱类设备仿真分析、支柱类设备设计施工两方面阐述了国内外研究的现状,对比了结构整体的分析研究,分析了从静力角度对变电站支柱类设备模型进行计算的不足之处,指出了目前对支柱类开关设备的风振响应动力分析与测试研究存在的问题;并对大风区支柱类设备大幅风振引起的隔离开关开合困难及疲劳损伤、断裂问题的未来研究方向进行了展望。     

Preparation and Optical Properties of Transparent Eu3+:Y3Al5(1−x)Sc5xO12 Ceramics

Using a novel combustion method, Eu-doped Eu:yttrium aluminum garnet (YAG) and Eu:YSAG powders, and transparent Eu:YSAG ceramics were fabricated. The optical properties of these transparent ceramics have been measured, and a reduced peak splitting of Eu³⁺ for ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ was observed when 10 at.% Al³⁺ was substituted by Sc³⁺. The enhanced symmetry of the Eu sites in YAG lattice, which resulted from the expanded YSAG lattice by Sc³⁺ doping, is the main reason for the reduced peak splitting.     

功率为16.9 dBm增益大于20 dB的InP DHBT W波段功率放大器

A two-stage MMIC power amplifier has been realized by use of a l-μm InP double heterojunction bipolar transistor(DHBT).The cascode structure,low-loss matching networks,and low-parasite cell units enhance the power gain.The optimum load impedance is determined from load-pull simulation.A coplanar waveguide transmission line is adopted for its ease of fabrication.The chip size is 1.5×1.7 mm~2 with the emitter area of 16×1μm×15μm in the output stage.Measurements show that small signal gain is more than 20 dB over 75.5-84.5 GHz and the saturated power is 16.9 dBm @ 79 GHz with gain of 15.2 dB.The high power gain makes it very suitable for medium power amplification.     

分散固相净化与气相色谱测定竹笋中21种农药残留

通过比较不同吸附剂对竹笋提取液的净化效果和对电子捕获检测器(electron capture detector,ECD)基线的影响,建立竹笋中21种有机氯和拟除虫菊酯类农药残留的气相色谱分析方法。竹笋样品用乙腈提取,加入无水硫酸镁、弗罗里硅土、N-丙基二乙胺(primary secondary amine,PSA)、强阳离子、石墨化炭黑进行分散固相净化,气相色谱-ECD测定。方法学结果表明,竹笋中21种有机氯和拟除虫菊酯农药具有良好的线性关系,检出限为0.079~1.77 μg/kg,定量限为0.26~5.89 μg/kg,经PSA净化平均回收率为92.97%,相对标准偏差为1.06%~6.07%。方法应用于我国竹笋主产区的质量安全风险监测,230个样品中,除了氰戊菊酯,其余农药均有不同程度的检出,其中检出率最高的是p,p′-滴滴伊(33.48%)、δ-六六六(26.52%)和氯氟氰菊酯(26.09%);检出含量和超标率最高的是噻嗪酮,为9 508.9 μg/kg和6.96%。     

多国规范平屋盖围护结构外表面设计风压对比研究

对比分析了中国GB 50009-2012、德国DIN 1055-4、美国ASCE/SEI 7-10、日本AIJ-2004、欧洲BS EN 1991-1-4:2005、加拿大NBC-2005、澳大利亚/新西兰AS/NZS 1170.2:2011、英国BS 6399-2:1997等规范中关于平屋盖围护结构外表面设计风压的有关规定。为便于比较,将各国规范风荷载标准值统一换算为外表面设计风压系数与基本风压乘积的形式。并且将外表面设计风压统一换算为与时距10min、重现期50a的基本风速相对应的值。针对外表面设计风压相关因素,对风向、风压分区、面积折减、建筑尺寸等进行了对比研究。最后,结合平屋盖风洞试验,探讨了外表面设计风压的具体取值建议。研究表明：平屋盖围护结构外表面设计风压的确定,建议考虑360°全风向;对屋盖边缘应进行风压分区,角部也应进行单独的风压分区;屋盖表面不同位置建议采用不同的面积折减公式;针对不同高度或宽高比建筑给定不同的外表面设计风压建议取值。     

集中式监控系统通讯协议的设计及实现

文章结合实际系统中一个通信协议的设计过程,较为详细地介绍了协议工程学的一般原理及方法,并结合工程实际详细阐释了在实例系统中这些原理和方法的应用。文章所选实例具有一定的代表意义,在各种实时监控、数据采集等系统工程中,该例所应用的一些协议工程学的基本原理及方法具有较广泛的指导作用。     

国内外保健食品管理法规标准比较研究(续完)

为给中国的保健食品管理提供借鉴 ,将中国大陆、澳大利亚、欧盟、日本、美国、中国台湾以及食品法典委员会 (CAC)有关保健 (功能 )食品或食品健康声称的法规、标准作为比较对象 ,重点分析和比较这些国家或地区在保健 (功能 )食品范畴、法律地位、产品成分、剂型、安全和功效要求等方面的异同 ,了解国外保健食品管理法规及标准建立的背景及科学依据。通过介绍各国或各地区针对保健 (功能 )食品或其标识、声称所建立的审批或审核机制 ,分析其管理模式的利弊 ,提出完善我国保健食品管理体系的意见和建议 ,为探讨今后进行国际协调的可能性提供技术依据。