Development and characteristics analysis of recessed-gate MOS HEMT

An AlGaN/GaN recessed-gate MOSHEMT was fabricated on a sapphire substrate. The device, which has a gate length of 1 μm and a source-drain distance of 4 μm, exhibits a maximum drain current density of 684 mA/mm at Vgs = 4 V with an extrinsic transconductance of 219 mS/mm. This is 24.3% higher than the transconductance of conventional AlGaN/GaN HEMTs. The cut-off frequency and the maximum frequency of oscillation are 9.2 GHz and 14.1 GHz, respectively. Furthermore, the gate leakage current is two orders of magnitude lower than for the conventional Schottky contact device.     

Design and fabrication of a planar patch-clamp substrate using a silicon-on-insulator wafer

noise.     

Particular electrical quality of a-plane GaN films grown on r-plane sapphire by metal-organic chemical vapor deposition

Nonpolar (11(2)0) a-plane GaN films have been grown by low-pressure metal-organic vapor deposition on r-plane (1(1)02) sapphire substrate. The structural and electrical properties of the a-plane GaN films are investigated by high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and van der Pauw Hall measurement.It is found that the Hall voltage shows more anisotropy than that of the c-plane samples; furthermore, the mobility changes with the degree of the van der Pauw square diagonal to the c direction, which shows significant electrical anisotropy. Further research indicates that electron mobility is strongly influenced by edge dislocations.     

多绞屏蔽线处理及焊接工艺

介绍了屏蔽线的分类及结构组成;分别以线束中含有少量屏蔽线和多股屏蔽线为例,通过分步说明和图例示范,阐述了两大类情况下,各种屏蔽线的处理方法;并对各种处理方法的应用场合和实际特点给予了重点说明;最后,结合实际工作经验,对多绞屏蔽线处理过程中的常见问题及注意事项进行了归纳和总结.     

Phthalocyanine‐Based 2D Conjugated Metal‐Organic Framework Nanosheets for High‐Performance Micro‐Supercapacitors

2D conjugated metal‐organic frameworks (2D c‐MOFs) are emerging as a novel class of conductive redox‐active materials for electrochemical energy storage. However, developing 2D c‐MOFs as flexible thin‐film electrodes have been largely limited, due to the lack of capability of solution‐processing and integration into nanodevices arising from the rigid powder samples by solvothermal synthesis. Here, the synthesis of phthalocyanine‐based 2D c‐MOF (Ni₂[CuPc(NH)₈]) nanosheets through ball milling mechanical exfoliation method are reported. The nanosheets feature with average lateral size of ≈160 nm and mean thickness of ≈7 nm (≈10 layers), and exhibit high crystallinity and chemical stability as well as a p‐type semiconducting behavior with mobility of ≈1.5 cm² V^?1 s^?1 at room temperature. Benefiting from the ultrathin feature, the nanosheets allow high utilization of active sites and facile solution‐processability. Thus, micro‐supercapacitor (MSC) devices are fabricated mixing Ni₂[CuPc(NH)₈] nanosheets with exfoliated graphene, which display outstanding cycling stability and a high areal capacitance up to 18.9 mF cm^?2; the performance surpasses most of the reported conducting polymers‐based and 2D materials‐based MSCs.     

激光诱导银纳米颗粒薄膜和微结构

利用可见激光诱导化学沉积方法在玻璃基底上制备纳米银薄膜和微结构。玻璃样品池中装满柠檬酸钠和硝酸银的混合透明溶液,当一束可见连续激光正入射样品池一段时间后,在辐照区域的玻璃内壁上便可以形成一层光亮的银膜。银膜沉积的速度受到激光功率密度、激光波长、辐照时间以及混合溶液的浓度等条件的影响。利用X射线衍射、原子力显微镜和拉曼光谱仪等手段对制备的薄膜的成分、表面形貌和拉曼活性等性质进行了表征和分析。利用此方法制备的银膜具有良好的表面增强拉曼散射活性。同时,利用双光束干涉的方法在玻璃基底上诱导出不同周期的银纳米颗粒光栅。     

独创性与可理解性——基于信息论美学的建筑创作

运用信息论美学的方法,揭示建筑设计与美学的本质,意在提高建筑创作质量,丰富建筑设计途径指出信息论建筑美学要求建筑设计创新信息的规模与频率适度,使独创性与可理解性有机结合,受众才可能领悟建筑师的设计创意,并引起审美共鸣.适度的创新信息和层级分布是建筑创作的核心.     

广州城市交通系统与土地利用协调研究

改革开放以来,广州城市交通系统与土地利用特点发生了巨大变化,两者之间的不协调客观存在,协调好两者关系必须以交通系统建设引导土地利用台理开发、确定好与交通系统相协调的城市空间布局战略、选择适宜高密度集中开发模式的公共交通模式,并对交通与土地利用规划进行一体化编制。     

多桩型复合地基设计及工程应用

通过对某高层框架结构多桩型复合地基设计,讨论了多桩型复合地基的承载力和沉降计算方法,对两种桩型联合应用的设计方案选择进行了分析,并对最终复合地基的承载力及地基变形进行了计算。计算结果与现场实测一致,满足工程精度要求。说明在某些工程地质条件下联合运用两种不同性状的桩型,可以获得更加合理的地基处理效果。     

浅谈直埋热力管道设计计算及安装构造的要点

本文就直埋热力管道的强度设计计算方法及安装构造要点作简单的介绍,从直埋管道的破坏方式、强度验算及稳定验算等方面分析了直埋管道的失效方式及进行应力验算的方法,并就防止薄弱部件的破坏提出具体的设计方法。