12千兆赫,NF为1.8分贝的低噪声GaAsFET

据报导三菱电机的MGF-1403型是频率为12千兆赫,最低噪声系数NF_(min)为1.8分贝,功率增益高达10.5分贝的低噪声GaAsFET.同样频率下的最大有用增益MAG达14分贝.在卫星广播上使用.甚至可用在更高的Ku带(12.4—17.6千兆赫).18千兆     

中国陆相油气的形成和运移(Ⅱ)

本文(Ⅰ)着重研究了中国陆相湖盆沉积物中有机质向油气演化的过程.本文(Ⅱ)阐明了现代青海湖沉积物埋藏初期及早期成岩作用过程中有机质的演化特征.其结果表明陆相有机质大量开始向石油转化的深度随不同地区、不同时代、不同类型的有机质而异.最后,运用特征有机化合物、稀有气体同位素等资料,结合构造发展史阐述我国陆相油气运移的类型、规模和途径.指出近油源短距离是陆相油气运移的基本特征.     

我国正负术历史

九章算术大約在公元一世紀編集成书,其中已著录正负术,这是我国古代数学上的光輝成就。正負术的产生有它在数学本身內在的发展,但为什么我国很早就熟悉了正負术,这和我国古代天文学的发展有关。东汉元和二年(85),我国天文学家创制的四分曆中,明白的記載了正負术的方法。它說: “強正弱负也。其強弱相減,同名相去;异名从之,从強进少为弱,从弱退少为強。”四分曆在計算太阳的視位置度数时,以不滿整度数部分用少、半、太来区别。少是1/4,半是2/4,太是3/4。比“少”多一些的叫少强,比“少”少一些的叫少弱。它們间的关系是:     

基于共前缀连续长度码的测试数据的压缩和解压方法

为减少测试数据存储量。提出了一种省略FDR码前缀的变一变长度压缩码．称之为共前缀连续长度码CPRL（Co—Prefixal Run Length）。压缩过程分两步，先对测试集差分运算．然后采用CPRL码编码差分向量。它的解压体系结构由一个解码器和循环扫描寄存器CSR（Cyclical Scan Register）组成。针对ISCAS-89基准电路硬故障集的实验结果表明，该方法是一种非常高效的压缩方法。     

业务疏导技术在WDM网络及OPS网络中的应用

在波分复用(WDM)光网络中,可使用业务疏导(Traffic Grooming)技术来提高网络性能,降低网络成本.详细阐述了WDM光网络中业务疏导的基本概念及主要目标,并对国内外研究现状进行了总结.最后介绍了OPS光交换网络中使用的业务疏导技术.     

煤渣式友爱

有的人伤害了对方,完全是出于一种自我保护意识,而且这种意识人皆有之,通常是为了使自己不受伤害,又无路可走,才出此下策。     

双向有线电视网多业务QoS保障机制实现方法

一概述 经过20多年的建设和发展，我国有线电视网络作为国家重要的信息化基础设施，已成为世界上用户规模最大的有线电视网络。到2006年，多个省市完成了数字电视整体转换，有线数字电视用户总量达到千万户。有线电视数字化后，有线电视向双向化、多功能的方向发展．部分网络公司率先实现了基于有线电视网络开展宽带数据接入、视频点播等双向化、多功能业务。     

Chemical Oxidation of La2CuO4 Epitaxial Thin Films Grown by Pulsed Laser Deposition

Chemical oxidation is used to induce superconductivity in La2CuO4 expitaxial thin films fabricated by pulsed laser deposition technique. Details about the influence of oxidation time on structural, surface morphology, Raman spectra, and electrical properties have been investigated. The results convince that successful uptake of oxygen occurs in the oxidized films, and the content of the inserted oxygen increases with increasing oxidation interval. The possible mechanism for the excess oxygen insertion into the film is also discussed.     

A Base-Emitter Self-Aligned Multi-Finger Sil-xGex/Si Power Heterojunction Bipolar Transistor

With a crystal orientation dependent on the etch rate of Si in KOH-based solution, a base-emitter self-Migned large-area multi-finger configuration power SiGe heterojunction bipolar transistor （HBT） device （with an emitter area of about 880μm^2） is fabricated with 2μm double-mesa technology. The maximum dc current gain is 226.1. The collector-emitter junction breakdown voltage BVcEo is 10 V and the collector-base junction breakdown voltage BVcBo is 16 V with collector doping concentration of 1 × 10^17 cm^-3 and thickness of 400nm. The device exhibited a maximum oscillation frequency fmax of 35.5 GHz and a cut-off frequency fT of 24.9 GHz at a dc bias point of Ic = 70 mA and the voltage between collector and emitter is VCE = 3 V. Load pull measurements in class-A operation of the SiGe HBT are performed at 1.9 GHz with input power ranging from OdBm to 21 dBm. A maximum output power of 29.9dBm （about 977mW） is obtained at an input power of 18.SdBm with a gain of 11.47dB. Compared to a non-self-aligned SiGe HBT with the same heterostructure and process, fmax and fT are improved by about 83.9% and 38.3%, respectively.     

Measuring Grüneisen Parameter of Lead by High Pressure-Jump Method

Using the technology of pressure jump, variations of temperature associated with pressure from 2.4 GPa to 4.6 GPa are measured for lead. The Grfuneisen parameter is calculated from the thermodynamic relation γ =（Ks/T）（aT/aP）s, in which substitution of △T/△P for aT/aP at median pressure is strictly justified. The correction of temperature change is carried out by analysing the experimental data, which makes the process more approaching to an adiabatic condition. The calculated values of △T/ △ P and γ gradually decrease with the increasing pressure. The decrease trend is consistent with the previous work. The γ values in the range of 2-3 GPa are averagely higher than the results of Ramakrishnan et al., indicating the effect of temperature correction. The improved method is promising for measurements of Grfineisen parameter to higher pressure range.