Effect of Different Substrate Temperature on Phosphorus-Doped ZnO Thin Films Prepared by PLD on Sapphire Substrates

Phosphorus-doped ZnO （ZnO：P） thin films are deposited on a c-plane sapphire in oxygen at 350℃, 450℃, 550℃ and 650℃, respectively, by pulsed laser deposition （PLD）, then all the ZnO：P samples are annealed at 650℃ in oxygen with a pressure of 1 × 10^5 Pa. X-ray diffraction measurements indicate that the crystalline quality of the ZnO：P thin films is improved with the increasing substrate temperature from 350℃ to 550℃. With a further increase of the deposition temperature, the crystalline quality of the ZnO：P sample is degraded. The measurements of low-temperature photoluminescence spectra demonstrate that the samples deposited at the substrate temperatures of 350℃ and 450℃ show a strong acceptor-bound exciton （A^0X） emission. The electrical properties of ZnO：P films strongly depend on the deposition temperature. The ZnO：P samples deposited at 350℃ and 450℃ exhibit p-type conductivity. The p-type ZnO：P film deposited at 450℃ shows a resistivity of 1.846Ω·cm and a relatively high hole concentration of 5.100 × 10^17 cm^-3 at room temperature.     

超分子螯合树脂--杯[4]芳烃接枝纤维素的设计、合成与吸附性能

通过纤维素多乙烯多胺衍生物2a~2c与1,3-二环氧丙基杯[4]芳烃3反应,合成了螯合树脂杯芳烃接枝纤维素4a~4c,用红外、元素分析和SEM等对其结构和形貌进行了表征.通过含氮量推算出新螯合树脂4a~4c中每个纤维素单元的杯芳烃接枝取代度分别为0.75、0.82和0.87.金属阳离子吸附性能实验表明,杯芳烃单元的引入在吸附过程中有重要作用,该螯合树脂结合了杯芳烃和纤维素的各自吸附性能优势,不仅吸附容量较高,而且表现出高的选择性吸附能力.树脂4b和4c对Ni2+离子表现出很高的吸附选择性,4a~4c的Ni2+饱和吸附容量分别达到2.96 mmol/g、2.93 mmol/g和2.66 mmol/g.在pH<4的强酸性条件下树脂的吸附能力迅速下降.该树脂用10%的氨水解吸附后有较好的重复使用性.     

A high-fidelity memory scheme for quantum data buses

A novel quantum memory scheme is proposed for quantum data buses in scalable quantum computers by using adjustable interaction. Our investigation focuses on a hybrid quantum system including coupled flux qubits and a nitrogen–vacancy center ensemble. In our scheme, the transmission and storage(retrieval) of quantum state are performed in two separated steps, which can be controlled by adjusting the coupling strength between the computing unit and the quantum memory. The scheme can be used not only to reduce the time of quantum state transmission, but also to increase the robustness of the system with respect to detuning caused by magnetic noises. In comparison with the previous memory scheme, about 80% of the transmission time is saved. Moreover, it is exemplified that in our scheme the fidelity could achieve 0.99 even when there exists detuning, while the one in the previous scheme is 0.75.     

Iterative filtered ghost imaging

It is generally believed that, in ghost imaging, there has to be a compromise between resolution and visibility. Here we propose and demonstrate an iterative filtered ghost imaging scheme whereby a super-resolution image of a grayscale object is achieved, while at the same time the signal-to-noise ratio (SNR) and visibility are greatly improved, without adding complexity. The dependence of the SNR, visibility, and resolution on the number of iterations is also investigated and discussed. Moreover, with the use of compressed sensing the sampling number can be reduced to less than 1% of the Nyquist limit, while maintaining image quality with a resolution that can exceed the Rayleigh diffraction bound by more than a factor of 10.     

张量对称类上诱导算子的y-数值半径(英文)

本文研究了诱导矩阵K(A)的y-数值半径ry(K(A))、y-可分数值半径ryχ(K(A))与范数A2、广义矩阵函数dχG(A)之间的关系问题.利用ry(K(A))及ryχ(K(A))的概念,得到了ry(K(A))、ryχ(K(A))、‖A‖2、dGχ(A)它们之间的两个不等式.     

2种苯并吡喃类查尔酮天然产物的全合成

2种苯并吡喃类查尔酮天然产物的全合成;全合成;苯并吡喃类查尔酮;三羟基苯乙酮;柠檬醛;苯甲醛     

分支定界法及其自组织异步并行实现

在讨论分支定界法的并行计算的基础上，就分支定界法求解分段线性规划问题提出了一种具有自组织功能的并行计算过程，并给出了能提高并行效率的异步并行计算的实施方案．     

再论最近邻判别分析

一、引言: 设(X,θ)为在R~d×{1,…,M}中取值的随机向量,称X为指标变量,θ为类别变量。假定X的值已知,据此要对与其匹配的θ值进行判定,这就是判别分析问题。在(X,θ)的分布未知的情况下,为进行判别,除利用X的当前观察值外,还要借助于历史知识。设(X_i,θ_i),i=1,…,n,是(X,θ)的一组iid样本,常称为训练样本。此时我们考虑的问题是,利用(X_i,θ_i),i=1,…,n及X值对θ进行判别。假定在R~d中引进了某一距离函数p(x,     

智能平台下考虑主体心理行为的医疗服务供需匹配方法

基于智能平台的新兴医疗服务模式,可以有效缓解患者“看病难”问题。本文针对智能平台下医疗服务供需双方匹配的现实问题,提出了一种考虑主体心理行为的决策方法。在该方法中,考虑了医疗服务过程中主体的期望和犹豫不确定的心理特征。首先,比较双方主体在不同指标下的期望水平和评价信息之间的差距,计算得到双方差异度,并通过集结运算分别获得了双方满意度;在此基础上,分别以医疗服务供需双方的满意度最大为目标,构建了智能平台下医疗服务供需匹配的多目标优化模型,通过模型求解可得到最优匹配结果;最后,通过算例分析说明了本文提出方法的可行性和有效性。     

A New Method for High-Resolution NMR Spectra in Inhomogeneous Fields with Efficient Solvent Suppression

High-resolution nuclear magnetic resonance （NMR） is one of the most powerful tools for analyzing molecular structures and dynamics. Magnetic field homogeneity is required for conventional high-resolution spectra. However, there are many chemical and/or biological circumstances where the spatial homogeneities of the magnetic fields are degraded. Intense solvent signal is another obstacle for obtaining high-resolution spectra, especially in in vivo and in situ NMR spectroscopy. In this paper, a new pulse sequence based on intermolecular multiple quantum coherence （iMQC） was reported. This sequence can effectively remove the effect of magnetic field inhomogeneity and suppress the solvent signal. It can recover the spectral information such as chemical shifts, coupling constants, multiplet patterns, and relative peak areas in inhomogeneous fields. Theoretical analyses and experimental verifications are presented to demonstrate the feasibility of this method.