HgCdTe薄膜的输运特性及其应力调控

窄禁带直接带隙半导体材料碲镉汞(Hg1–xCdxTe)是一种在红外探测与自旋轨道耦合效应基础研究方面都具有重要应用意义的材料.本文对单晶生长的体材料Hg0.851Cd0.149Te进行阳极氧化以形成表面反型层,将样品粘贴在压电陶瓷上减薄后进行磁输运测试,在压电陶瓷未加电压时观察到了明显的SdH振荡效应.对填充因子与磁场倒数进行线性拟合,获得样品反型层二维电子气的载流子浓度为ns=1.25×10^16m^-2.在不同磁场下,利用压电陶瓷对样品进行应力调控,观测到具有不同特征的现象,分析应是样品中存在二维电子气与体材料两个导电通道.零磁场下体材料主导的电阻的变化应来源于应力导致的带隙的改变;而高场下产生类振荡现象的原因应为应力导致的二维电子气能级的分裂.     

Double-Shelled C@MoS2 Structures Preloaded with Sulfur: An Additive Reservoir for Stable Lithium Metal Anodes

The growth of Li dendrites hinders the practical application of lithium metal anodes (LMAs). In this work, a hollow nanostructure, based on hierarchical MoS₂ coated hollow carbon particles preloaded with sulfur (C@MoS₂/S), was designed to modify the LMA. The C@MoS₂ hollow nanostructures serve as a good scaffold for repeated Li plating/stripping. More importantly, the encapsulated sulfur could gradually release lithium polysulfides during the Li plating/stripping, acting as an effective additive to promote the formation of a mosaic solid electrolyte interphase layer embedded with crystalline hybrid lithium-based components. These two factors together effectively suppress the growth of Li dendrites. The as-modified LMA shows a high Coulombic efficiency of 98 % over 500 cycles at the current density of 1 mA cm⁻². When matched with a LiFePO₄ cathode, the assembled full cell displays a highly improved cycle life of 300 cycles, implying the feasibility of the proposed LMA.     

AlGaN基宽禁带半导体光电材料与器件

AlGaN基材料是带隙可调的直接带隙宽禁带半导体材料,是制备紫外(UV)光电子器件的理想材料.经过数十年的研究,目前已经在异质衬底外延生长AlGaN基材料、高效掺杂等方面取得了巨大进展.以此为基础,AlGaN基紫外光电器件制备领域也得到长足发展.在本综述中,主要介绍了高质量AlGaN基材料的MOCVD外延生长方法、掺杂方法以及近年来在紫外发光、紫外探测器件方面取得的进展.     

等离子体破裂期间电流猝灭特征研究

等离子体破裂会对托卡马克装置的安全运行造成严重威胁.等离子体破裂期间电流猝灭速率与电磁负载的大小及逃逸电流平台的形成都密切相关.本文对HL-2A装置等离子体破裂进行了统计分析,统计选用等离子电流的两个衰减区间90%-10%和80%-20%.分析结果表明:HL-2A装置等离子体破裂有四种不同的电流猝灭波形,两个衰减区间最小电流猝灭时间的参数区分别为2.6 ms和2.2 ms,并且不同衰减区间下平均电流猝灭时间统计分布明显不同.     

Experimental and Numerical Investigation on Effects of the Steam Ingestion on the Aerodynamic Stability of an Axial Compressor

In order to investigate the influence of steam ingestion on the aerodynamic stability of a two-stage low-speed axial-flow compressor, multiphase flow numerical simulation and experiment were carried out. The total pressure ratio and stall margin of the compressor was decreased under steam ingestion. When the compressor worked at 40% and 53% of the nominal speed, the stall margin decreased, respectively, by 1.5% and 6.3%. The ingested steam reduced the inlet Mach number and increased the thickness of the boundary layer on the suction surface of the blade. The low-speed region around the trailing edge of the blade was increased, and the flow separation region of the boundary layer on the suction surface of the blade was expanded; thus, the compressor was more likely to enter the stall state. The higher the rotational speed, the more significant the negative influence of steam ingestion on the compressor stall margin. The entropy and temperature of air were increased by steam. The heat transfer between steam and air was continuous in compressor passages. The entropy of the air in the later stage was higher than that in the first stage; consequently, the flow loss in the second stage was more serious. Under the combined action of steam ingestion and counter-rotating bulk swirl distortion, the compressor stability margin loss was more obvious. When the rotor speed was 40% and 53% of the nominal speed, the stall margin decreased by 6.3% and 12.64%, respectively.     

A Magnetic Nanoparticle-Based Time-Resolved Fluoroimmunoassay for Determination of the Cytokeratin 19 Fragment in Human Serum

A sensitive, rapid and novel measurement method for cytokeratin 19 fragment (CYFRA 21–1) in human serum by magnetic particle-based time-resolved fluoroimmunoassay (TRFIA) is described. Built on a sandwich-type immunoassay format, analytes in samples were captured by one monoclonal antibody coating onto the surface of magnetic beads and “sandwiched” by another monoclonal antibody labeled with europium chelates. The coefficient variations of the method were lower than 7 %, and the recoveries were in the range of 90–110 % for serum samples. The lower limit of quantitation of the present method for CYFRA 21–1 was 0.78 ng/ml. The correlation coefficient of CYFRA 21–1 values obtained by our novel TRFIA and CLIA was 0.980. The present novel TRFIA demonstrated high sensitivity, wider effective detection range and excellent reproducibility for determination of CYFRA 21–1 can be useful for early screening and prognosis evaluation of patients with non-small cell lung cancer.