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排序方式: 共有641条查询结果,搜索用时 125 毫秒
601.
Dr. Hong Lu Tian-Tian Zhao Jin-Hua Bai Dan Ye Prof. Dr. Peng-Fei Xu Prof. Dr. Hao Wei 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23743-23749
Highly selective divergent coupling reactions of benzocyclobutenones and indoles, in which the chemoselectivity is controlled by catalysts, are reported herein. The substrates undergo C2(indole)–C8(benzocyclobutenone) coupling to produce benzylated indoles and benzo[b]carbazoles in the Ni- and Ru-catalyzed reactions. A completely different selectivity pattern C2(indole)–C2(benzocyclobutenone) coupling to form arylated indoles is observed in the Rh-catalyzed reaction. Preliminary mechanistic studies suggest C−H and C−C activations in the reaction pathway. Synthetic utility of this protocol is demonstrated by the selective synthesis of three different types of carbazoles from the representative products. 相似文献
602.
Hong-Liang Lu Zhang-Yi Xie Yang Geng Yuan Zhang Qing-Qing Sun Peng-Fei Wang Shi-Jin Ding David Wei Zhang 《Applied Physics A: Materials Science & Processing》2014,117(3):1479-1484
Growth and interfacial properties of atomic layer deposited Al0.7Ti0.3O y on Ge have been investigated as a potential high-k gate dielectric for future Ge-based metal oxide semiconductor devices. A sandwich structure of Al2O3/TiO2 stack is proposed for Al2O3/TiO2 intermixing and high-k/Ge interfacial passivation. The film thicknesses and interface microstructure are characterized by spectroscopy ellipsometry and high-resolution transmission electron microscopy. X-ray photoelectron spectrometry is used to analyze the chemical composition and bonding states, and to reveal the band alignment of high-k/Ge heterojunctions. Metal-oxide-capacitors are formed by depositing aluminum electrodes to perform capacitance–voltage measurements for electrical characteristics. All evidences show a positive prospect of employing atomic layer deposited Al0.7Ti0.3O y as high-k gate dielectric for future Ge-based devices. 相似文献
603.
采用轴对称多弛豫时间格子Boltzmann(LB)方法,研究了圆柱形封闭谐振腔中圆盘形样品的声悬浮过程.模拟结果表明,(001)模式下谐振腔的共振长度L=0.499λ,在谐振腔中心引入样品后共振漂移量δL≈-0.9,这与线性声学理论计算结果基本相符.声悬浮力的LB模拟过程包含了黏滞性效应和共振漂移效应,所获得的模拟结果与理论公式计算值在量值上一致,而且其在细节上更符合实验现象.此外,LB模拟还揭示出了声悬浮过程中的声压波形畸变、声流和声辐射压等非线性声学效应. 相似文献
604.
Peng-Fei Duan Wei-Long Duan Qiong-Si Fu Min Tang Pei-Hua Chen 《International Journal of Theoretical Physics》2014,53(12):4402-4406
We propose a scheme to prepare a two-qubit remote entangled state based on four-qubit cluster state in cavity quantum electrodynamics which involves the interaction of the atoms with the cavity. Through using four-particle cluster state as a quantum channel, we shown that the probability and fidelity of the successful remote state preparation can approach unit. In addition, our protocol only need single qubit measurement instead of the conventional Bell-state measurement, then it is quite simple but also very robust to the cavity decay and the influence of the thermal field. 相似文献
605.
Hai-Jing Cao Yan-Yan Zhu Peng-Fei Li 《International Journal of Theoretical Physics》2014,53(2):419-425
We present a weak blind signature scheme based on a genuinely entangled six qubits state. Different from classical blind signature schemes and current quantum signature schemes, our quantum weak blind signature scheme could guarantee not only the unconditionally security but also the anonymity of the message owner. To achieve that, quantum key distribution and one-time pad are adopted in our scheme. Our scheme has the characteristics of classical security and quantum security. 相似文献
606.
The P-wave charm-strange mesons Ds0(2317) and Ds1(2460) lie below the DK and D* K threshold respectively. They are extremely narrow because their strong decays violate the isospin symmetry. We study the possible heavy molecular states composed of a pair of excited charm strange mesons. As a byproduct, we also present the numerical results for the bottonium-like analogue. 相似文献
607.
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609.
采用粒子模拟,得到了阳极杆箍缩二极管阳极钨针上电子的空间分布和入射角分布,分析二极管工作状态得到了电子的能量分布.在此基础上建立阳极杆箍缩二极管的蒙特卡罗模型,模拟得到了阳极杆箍缩二极管的辐射能谱和X射线的平均能量,并与实验结果进行了比较.结果表明:09006炮光子平均能量为0.441 MeV,计算该能谱射线经过不同厚度铅衰减片后的剂量衰减情况,与叠片法PIN探测器所测的实验数据基本一致.
关键词:
阳极杆箍缩二极管
粒子模拟
蒙特卡罗方法
X射线能谱 相似文献
610.
针对Ni基单晶合金建立初始压入γ 相的γ /γ' 模型和初始压入γ'相的γ'/γ 模型, 采用分子动力学方法模拟金刚石压头压入两种模型的纳米压痕过程, 计算两种模型[001]晶向硬度. 采用中心对称参数分析两种模型(001)相界面错配位错对纳米压痕过程的影响. 结果显示: 弛豫后, 两种模型(001)相界面错配位错形式不同, 其中γ'/γ 模型(001)相界面错配位错以面角位错形式存在; 压入深度在0.930 nm 之前, 两种模型(001)相界面错配位错变化不大, 压入载荷-压入深度及硬度-压入深度曲线较符合; 压入深度在0.930 nm之后, γ'/γ 模型(001)相界面错配位错长大很多, 导致相同压入深度时γ'/γ 模型比γ /γ'模型压入载荷和硬度计算结果小; 压入深度在2.055 nm之后, γ /γ'模型(001)相界面错配位错对γ 相中位错进入γ'相有阻碍作用, 但仍有部分位错越过(001) 相界面进入γ' 相中, γ'/γ 模型(001)相界面处面角位错对γ' 相中位错进入γ 相有更明显的阻碍作用, 几乎无位错越过(001) 相界面进入γ 相中, 面角位错的强化作用更明显, 所以γ'/γ 模型比γ /γ'模型压入载荷上升速度快. 相似文献