Results 41 to 50 of about 14,863 (167)

Modification of the Optical Polarization in High Al-Content AlGaN [PDF]

open access: yes, 2016
相比于传统紫外光源(如汞灯和氙灯),AlGaN半导体紫外光电子器件具有无汞污染、波长可调、体积小、集成性好、耐高温、抗辐射以及能耗低、寿命长等优点,在工业、农业、国防和医疗卫生等领域都有着广阔的应用前景和巨大的市场需求。然而,由于高Al组分AlGaN材料中存在诸多问题,例如外延生长困难、p型掺杂率低、发光偏振特性独特等等,导致深紫外波段器件的发光效率普遍较低,制约了深紫外发光器件的发展与应用。本论文采用第一性原理的计算模拟方法,围绕AlGaN材料中的光学偏振特性及其调控开展了系统的研究工作 ...
季桂林
core  

Multiple pregnancy with complete hydatidiform mole and coexisting normal fetus: systematic review and meta‐analysis of clinical outcomes from non‐randomized studies

open access: yesUltrasound in Obstetrics &Gynecology, Volume 67, Issue 3, Page 272-282, March 2026.
ABSTRACT Objective Complete hydatidiform mole and coexisting normal fetus (CHMCF) is a rare condition for which there is significant heterogeneity in diagnosis, counseling and management of complications. The objective of this study was to summarize the prevalence of clinical outcomes in reported cases of CHMCF.
N. Salmeri   +8 more
wiley   +1 more source

In Situ MOF Pyrolysis Construction of Hierarchical Porous Co‐Nanoparticles/Carbon Cloth Composites for Enhanced Electromagnetic Wave Shielding and Absorption

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT The development of high‐performance electromagnetic protection materials integrating broadband absorption and effective shielding capabilities is hindered by challenges in simultaneously optimizing multiple electromagnetic properties through conventional material designs.
Changlong Du   +9 more
wiley   +1 more source

正直流电压下油纸绝缘针板电极局放流注仿真研究

open access: yesGaoya dianqi, 2018
为了更好地研究直流电压下油纸绝缘系统针板电极局部放电的电荷分布特性,文中基于流体动力学扩散—漂移方程和双极电荷传输方程搭建仿真模型用以模拟空间电荷的分布,研究了电荷产生的和流注发展的过程与放电特性,得到了局部放电过程中电荷,电场和电势的发展趋势。研究表明:油纸绝缘针板电极的局放过程分为流注击穿油隙与电荷在纸板上积累两个阶段,油隙的击穿过程中,流注头部的电场强度与净电荷密度会不断增加,形成自持放电;当流注到达绝缘纸板表面并在纸面积累电荷,将形成屏蔽层,导致流注的电场分布与电荷分布减弱,逐渐形成零电场区域 ...
姚竣严   +4 more
doaj  

Application of colloidal dispersion gels in-depth conformance improvement in polymer flooding development of Daqing oilfield(胶态分散凝胶深度调剖技术在大庆油田聚驱开发中的应用)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2002
介绍了大庆油田应用胶态分散凝胶深度调剖技术的凝胶成胶机理、影响成胶的因素、凝胶在多孔介质中的渗流特征及现场试验效果.室内岩芯模拟研究及现场典型井试验表明,流动凝胶在多孔介质中可流动,在单井注入15000~20000 m3流动凝胶体系过程中,注入压力逐渐升高,可以实现深度调剖,更好地提高聚合物驱采收率.
XIEChao-yang(谢朝阳)   +5 more
doaj   +1 more source

Gravity‐Driven Inclination Sensor Based on Liquid Metal Interface Migration in Anisotropic Microchannels for Information Transmission and Continuous Surface Topography Scanning

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT With the continuous advancement of materials science and technology, the rare metal gallium has increasingly emerged as a promising alternative to the toxic metal mercury. Although existing research has predominantly focused on the high electrical conductivity and excellent deformability of liquid metal (LM), its intrinsic fluidic property ...
Feifan Guo   +6 more
wiley   +1 more source

Development and Optimization of a Cylindrical Laminated Methanol Steam Reforming Microreactor with Porous Metal as Catalyst Support [PDF]

open access: yes, 2016
摘要 以低碳醇为燃料的制氢微反应器可为燃料电池等微小型电子装置提供安全可靠的在线氢源,从而引起世界各国研究者的广泛关注。本文以多孔金属材料为载体,设计制造了一种新型层叠式柱形甲醇水蒸气重整制氢微反应器,可获得较佳的制氢效果。论文主要研究内容如下: (1)载体结构甲醇水蒸气重整制氢微反应器设计 利用Solidworks软件设计了一种新型层叠式柱形甲醇水蒸气重整制氢微反应器。其中蒸发腔设计栅板结构,可有效增强反应溶液的汽化效果以及重整腔入口流体分布的均匀性。载体板采用多孔金属材料,降低加工成本 ...
张军鹏
core  

F‐Mediated Precise Control Over Amorphous/Crystalline Fe/Ni‐Based Phosphides Heterostructure for Efficient Oxygen Evolution Reaction

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT Transition metal‐based amorphous/crystalline (a/c) heterostructured catalysts have garnered significant attention due to their exceptional activity, stability, and cost‐effectiveness. However, the precise synergistic regulation of interfacial composition and phase states remains challenging.
Haoran Li   +3 more
wiley   +1 more source

搏动性体外循环的脑电图观察——附16例分析

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 1982
体外循环应用于心内直视手术已有20多年的历史。但目前通用的体外循环机是以恒流血液注入动脉,不符合正常的循环生理。因此,要提高心脏手术的水平,需寻找一种更接近生理的灌注技术。根据人类心脏产生的血流灌注是一种搏动性灌注的原理,我们把我院研制的助搏器应用于体外循环手术,目的是使血流变为搏动性 ...
林志华
doaj  

Home - About - Disclaimer - Privacy