GaAs FET功率放大器温度补偿的设计

介绍了GaAs FET功率放大器温度补偿的基本原理,分析了GaAs FET功率放大器的增益随温度变化的原因,并给出了解决方法。此方法还可移植到其他类似需要温度补偿的放大器中。     

Measurements of neutron energy spectra of 9Be(d,n)10B reaction with a thick beryllium target

Novel measurements of the neutron energy spectra of the 9Be(d,n)10B reaction with a thick beryllium target are performed using a fast neutron time-of-flight(TOF)spectrometer for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The neutron contributions from the 9Be(d,n)10B reaction are distributed relatively independently for the ground state and the first,second,and third excited states of 10B.The branching ratios of the 9Be(d,n)10B reaction for the different excited states of 10B are obtained for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The branching ratio of the 9Be(d,n)10B reaction for the third excited state decreases with increase in the incident deuteron energy,and the branching ratios for the ground state and the second excited state increase with increase in the neutron emission angle.     

超声无铆静力学性能强化试验与机制研究*

无铆连接是一种薄板材料连接新技术,可在无需预成孔和表面预处理情况下,实现同种、异种、多层薄板材料高效连接,但由于无铆接头静力学性能较低,极大地限制了该连接技术的推广与发展。为解决这一难题,本文选用5A06铝合金与TA1钛合金进行同种金属无铆铆接,并在此基础上进行了超声金属焊接复合实验,基于静拉伸测试和扫描电镜分析,探究超声焊对无铆接头力学性能的强化机制。试验结果表明：超声焊可有效提升无铆接头力学性能,特别是对于铝合金无铆接头;超声焊使得铝合金板塑性提高,钛合金板则得到硬化;超声焊后无铆接头的受力形式发生改变,从颈部受力变为先焊合区受力再颈部受力,这是超声焊复合强化的根本原因;超声焊可使铝合金无铆接头内部形成一定深度的固相焊,使铝合金接头力学性能得到大幅提升;TA1钛合金无铆接头内部固相焊较浅,力学性能提升相对较低。     

Electroplating Cobalt Films on Silicon Nanostructures for Sensing Molecules

In this study, we electroplated Co and Cu on nano-spiked silicon substrates that were treated with femtosecond laser irradiations. With energy-dispersive X-ray (EDX) analysis by a scanning electron microscope (SEM), it was found that both Co and Cu are primarily coated on the spike surfaces without changing the morphology of the nanospikes. We also found that nanoscale bridges were formed, connecting the Co-coated silicon spikes. The formation of these bridges was studied and optimized through a series of time-controlled electroplating and oxidizing processes. The bridges are related to the oxidation of Co in the air. When it is irradiated with visible light, this special structure has shown a capability of interactions with carbon monoxide and carbon dioxide molecules. The electroplated cobalt may be used for gas sensors.     

Defect engineering for high-selection-performance of NO reduction to NH3 over CeO2（111） surface: A DFT study

To reduce the greenhouse effect caused by the surgery of nitrogen-oxides concentration in the atmosphere and develop a future energy carrier of renewables, it is very critical to develop more efficient,controllable, and highly sensitive catalytic materials. In our work, we proposed that nitric oxide（NO）, as a supplement to N₂ for the synthesis of ammonia, which is equipped with a lower barrier. And the study highlighted the potential of CeO₂（111） nanosheets with La doping a...     

内变量和伪弹性的热力学模型

在固体相变中经常出现滞后,需要内变量以描述滞后现象。对记忆合金单晶拉伸实验,所需内变量是奥氏体和马氏体区域的界面数。本文首先讨论有关的实验结果,然后给出以此内变量为基础的热力学模型。     

MARLOWE-固体中两体碰撞的模拟计算程序及其应用

MARLOWE是一个基于两体碰撞近似模拟各类结构的固体中原子级联过程的通用计算机程序。本文简单介绍了该程序的理论基础、所采用的近似、特点及其适用的范围。文中还概述了我们用这一程序研究的部分物理工作。     

Solubility and optical activity of Bi12SiO20 crystals

In this paper the solubility and optical activity of Bi₁₂SiO₂₀ (BSO) single crystals grown in aqueous NaOH under hydrothermal conditions were reported. BSO was found to have a positive solubility coefficient from 350 to 400 °C in 0.5–3 M NaOH, as well as a positive dependence on mineralizer concentration. The reason why additional SiO₂ should be introduced in the mineralizer to grow high quality BSO was analyzed. High quality and colorless BSO crystals were grown using 4 M NaOH as a mineralizer and additional 3 wt% SiO₂ introduced in the mineralizer. Results showed that the optical activity of hydrothermal colorless BSO was superior to that of BSO grown by the Czochralski (Cz) method.     

New Quinoxaline-Based Blue Emitters:Molecular Structures,Aggregation-Induced Enhanced Emission Characteristics and OLED Application

Three new deep blue light emitters,bearing quinoxaline with different substituents(biphenyl/pyrene)at the 1-or 2-position,were synthesized by a Pd-catalysed cou...