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排序方式: 共有89条查询结果,搜索用时 15 毫秒
51.
Mujahid Mustaqeem Pi-Tai Chou Saqib Kamal Naveed Ahmad Jia-Yu Lin Yu-Jung Lu Xing-Hao Lee Kung-Hsuan Lin Kuang-Lieh Lu Yang-Fang Chen 《Advanced functional materials》2023,33(19):2213587
Spin optoelectronics is an indispensable key for the future development of spintronics. In conventional spin light emitting diodes (LEDs), spin-polarized carrier pairs are injected electrically into the light emitting layer and create circularly polarized light (CPL). Generally, spin-polarized carriers are accomplished using ferromagnetic contacts or applying an external magnetic field, which will produce several drawbacks, including low temperature operation, low spin-polarized carriers injection efficiency, etc. To circumvent the existing shortcomings, here, an alternative approach is proposed and achieves spin-polarized LEDs at room temperature based on quantum dots (QDs)/chiral metal-organic framework heterojunction without using ferromagnetic contacts or magnetic fields. The spin-polarized injected layer composed of self-assembled monolayer (SAM)/Chiral-MOF ([Sr(9,10-adc)(DMAc)2]n)) film, which produces spin-polarized holes with spin orientation, determining the polarization and strength of circularly polarized electroluminescence (CP-EL). The spin-QLED emits CP-EL at a rate of 12.24% efficiency, which provides an excellent alternative to generate new functionality for conventional QLEDs. The approach is anticipated to be very useful, enabling to offer a general methodology for generating not yet realized spin optoelectronic devices. 相似文献
52.
重庆地区地基承载力的确定——《工程地质勘察规范》(DBJ50-043-2005)讲座之四 总被引:1,自引:1,他引:0
<正>引言地基承载力的确定是地基勘察评价的关键内容之一。新颁布的重庆市工程建设标准《工程地质勘察规范》(DBJ50-043-2005)(以下简称本标准)在地基承载力确定方 相似文献
53.
<正>引言岩土性质指标的确定是工程地质勘察评价的核心内容之一,新颁布的重庆市工程建设标准《工程地质勘察规范》(DBJ50-043-2005)(以下简称本标准)用专章对此进行了规定,在岩土样最小试验数据量、单指标统计、双指标统计、 相似文献
54.
Polarization-Dependent Optimization of Fiber-Coupled Terahertz Time-Domain Spectroscopy System 下载免费PDF全文
The optimization of the fiber-coupled terahertz time-domain spectroscopy (THz-TDS) system is performed by changing the polarization of the optical excitation pulse centered at 1550 nm. InGaAs/InAlAs multilayer structures based photoconductive antennas are used in TDS setup as both the emitter and receiver. The experimental results demonstrate that not only the THz signal power but also the temporal waveform vary with the rotation of the exciting pulse polarization. Maximum output power of the emitter is obtained when the polarization of the pump pulse is perpendicular to the edge of the metal electrodes. At this moment the THz waveform is close to a single-cycled pulse. However, double THz pulses could be recorded when the pump laser polarization is parallel to the electrodes. Laser pulse splitting induced by the birefringence of the optical fiber may attribute to the polarization-dependent performance of the fiber-coupled THz-TDS system. 相似文献
55.
对HEVC整像素运动估计算法进行优化,目的是在保持编码视频压缩后码流率和解码视频图像质量基本不变的同时,降低编码耗时。首先,统计了不同视频序列的进行帧间预测时整像素运动估计的搜索步长的分布。进而根据统计结果,改进了不同搜索步长下的分支搜索模板。同时调整了整像素运动估计的提前终止条件。最终比较了测试视频序列优化前后编码输出的YUV分量、码流和耗时。实验结果表明,对于class E(1 920×1 080)视频序列,在编码后视频质量的客观值(YUV分量)最多下降0.182 2 d B,比特率最多上升0.40%,耗时最少下降1.25%。 相似文献
56.
目的 优化枇杷核抗性淀粉的最佳制备条件,并对枇杷核抗性淀粉的结构特征和理化性质进行探究,以期得到枇杷果核再利用的可行性。方法 选用淀粉乳浓度、超声功率、酶添加量、酶解时间为主要条件,通过压热超声酶解法制备枇杷核抗性淀粉;采用扫描电镜、X-射线衍射分析、傅里叶红外变换光谱研究不同品种枇杷核淀粉与抗性淀粉的颗粒结构和理化性质。结果 最佳制备条件:淀粉悬浮液浓度30%、超声提取功率设定180 W、普鲁兰酶添加量25 U/g、酶解时间10 h,在此条件下,枇杷核抗性淀粉得率为12.457%。枇杷淀粉颗粒近椭圆型,抗性淀粉形状变为块状堆叠。枇杷淀粉均呈现C型晶体特征,抗性淀粉均为B型晶体特征。抗性淀粉的红外光谱图在3000-4000 cm-1之间的吸收峰变窄、多,其他区域与淀粉的光谱基本一致。结论 优化后的方法制备效率稳定,在此条件下制备的枇杷核抗性淀粉,形态结构与理化性质良好,可以为枇杷核综合利用提供依据。 相似文献
57.
目的探究不同处理方式对蔬菜中拟除虫菊酯类农药残留的影响。方法分别于2016年10月、2017年1月、2月在济南市农贸市场随机抽样采集根茎类,叶菜类,果菜类,薯芋类蔬菜样品共34份,将样品粉碎后提取拟除虫菊酯,采用酶联免疫吸附法(enzyme linked immunosorbent assay,简称ELISA)检测蔬菜中拟除虫菊酯残留量。随后,分别通过碱水溶液浸泡、洗涤剂清洗的方法处理样品,检测处理后蔬菜中拟除虫菊酯残留量,评价不同处理方法对蔬菜中拟除虫菊酯类残留的影响。结果 34份蔬菜中拟除虫菊酯检出率为100%;蔬菜中拟除虫菊酯类农药的残留量随着采样时间的不同而发生变化,秋季残留量较高,冬季残留量较低;碱处理和洗涤剂洗涤对蔬菜中拟除虫菊酯无明显去除效果。结论拟除虫菊酯类农药普遍存在与蔬菜中,且经碱处理和洗涤剂处理均无法有效去除蔬菜中此类农药残留。 相似文献
58.
针对塔里木油田泛哈拉哈塘区块侧钻井在奥陶系桑塔木组钻进期间的井壁失稳问题,通过实验分析井壁失稳的机理为该区块岩性属硬脆性泥岩,层理和裂隙发育,钻井液滤液的渗入导致填充物水化分散;新井眼周围失去原有的力学平衡,形成应力坍塌;钻井液受CO32-/HCO3-污染导致性能恶化。以及影响井壁失稳的
因素有:井斜角、钻井液浸泡时间和钻井液密度。并针对该区块桑塔木组侧钻期间的复杂特点和影响井壁失稳的因素从造斜点的选择、工程措施、钻井液措施和碳酸根碳酸氢根污染的处理等方面提出合理的应对措施,对在桑塔木组侧钻期间的安全钻进具有指导意义。 相似文献
59.
Kuwano N Jia-Yu Tajima R Koga S Tsukamoto S Ohno Y 《Journal of electron microscopy》2004,53(5):541-544
The application of a focused ion beam (FIB) mill equipped with a microsampling unit to a tin-plated specimen was reported briefly. Tin-plating has a serious problem: Whiskers are liable to grow on the surface of tinplates. In order to clarify the mechanism of the whisker growth, detail characterisation is conducted using transmission electron microscopy (TEM). However, it is difficult to prepare specimens for TEM observation without the influences of mechanical damages. It was demonstrated that FIB etching was successfully used to observe a three-dimensional microstructure by scanning ion microscopy (FIB-imaging) and to prepare thin films for TEM observation. The observation has revealed the formation of precipitates of Ni(3)Sn(4) that is considered to be strongly related to the whisker growth. 相似文献
60.
Xin-E Shi Yue-Feng Li Long Jia Hong-Lei Ji Zi-Yi Song Jia Cheng Guo-Fang Wu Cheng-Chuang Song Qiang-Ling Zhang Jia-Yu Zhu Gong-She Yang 《International journal of molecular sciences》2014,15(5):8526-8538
MicroRNAs (miRNAs), a class of small non-coding RNAs, have emerged as novel and potent regulators of adipogenesis. However, few miRNAs have been fully investigated in porcine adipogenesis, given the fact that pig is not only an apropos model of human obesity research, but also a staple meat source of human diet. In this study, we showed that miRNA-199a-5p is highly expressed in porcine subcutaneous fat deposits compared to several other tissue types and organs measured alongside. Overexpression of miR-199a-5p in porcine preadipocytes significantly promoted cell proliferation while attenuating the lipid deposition in porcine adipocytes. By target gene prediction and experimental validation, we demonstrated that caveolin-1 (Cav-1) may be a bona fide target of miR-199a-5p in porcine adipocytes, accounting for some of miR-199a-5p’s functions. Taken together, our data established a role of miR-199a-5p in porcine preadipocyte proliferation and differentiation, which is at least partially played by downregulating Cav-1. 相似文献