铝掺杂氧化锌的合成及结构分析

采用共沉淀法合成了系列铝掺杂氧化锌粉体Zn1-xAlxO（0≤X≤0．028）．通过ICP-OES方法测得样品中的Al含量,并利用Rietveld方法对分别在1000和120012下煅烧获得的铝掺杂氧化锌Zn1—x AlxO（0≤X≤0．028）进行了结构分析．结果发现Zn1-xAlxO的晶胞参数a,c开始随铝掺杂浓度的提高明显减小,随后这种影响趋势逐渐降低,甚至随舢离子浓度进一步增加晶胞参数逐渐增大,由此确定铝在氧化锌中的固溶度,摩尔分数为2．2％,当铝掺杂过量时,铝更倾向于与氧化锌形成ZnAl2O4尖晶石化合物而不是取代Zn^2＋位置形成固溶体．研究还发现铝掺杂氧化锌的UV-Vis吸收光谱较纯氧化锌样品产生了明显的红移现象,这进一步确认了铝离子确实进入了氧化锌晶格形成了固溶体．     

适应新工科建设的“计算化学与应用”教学模式

以“学生为中心,教师为主导;理论为基础,实践为主线;育人为目的,能力为目标”作为基本原则,建立一种适应当代新工科建设的“计算化学与应用”新教学模式。形成优化的课程教学体系和科学有效的考核评价方法。通过“理论与实践、基础与前沿、学习与研究”相融合的教学组织模式,全面提升学生的研究能力和创新能力。所设计的新教学模式将计算机、化学、工程等多学科进行交叉和融合,凸显新工科特色。建立了符合新工科建设需求的创新型高素质人才培养模式,课程改革和建设取得了显著成效。     

基于铁(Ⅲ)-硝基-萨洛芬配合物的共振光散射光谱法测定油茶籽油和自来水中久效磷的含量

提出了基于铁(Ⅲ)-硝基-萨洛芬(I-N-Sal)配合物的共振光散射光谱法测定油茶籽油和自来水中久效磷含量的方法。分别取适量的5-硝基水杨醛和邻苯二胺的乙醇溶液,于40℃水浴回流0.5 h,然后在搅拌条件下加入一定量的九水合硝酸铁的乙醇溶液,反应4 h后,过滤、干燥得到深橙红色固体粉末。紫外-可见吸收光谱、傅里叶变换红外光谱、元素分析、核磁共振氢谱等表征结果显示,制备的产物为四齿席夫碱金属配合物,化学式为C₂₀H₁₂N₄O₆Fe。在弱碱性条件(pH 8.5)下将0.700μmol·L^-1制备的I-N-Sal配合物与久效磷静置反应20 min,形成复合物使体系在300 nm处产生强烈的共振光散射信号。结果表明：I-N-Sal配合物对久效磷表现出较好的选择性;久效磷浓度在0.100～1.100μmol·L^-1内与对应的共振光散射强度呈线性关系,检出限(3s/k)为30 nmol·L^-1;方法用于实际油茶籽油和自来水样品中久效磷的测定,所得...     

带圆开孔的弹性约束适度椭圆板的自由振动分析

采用弹性理论并结合边界摄动技术,对带中心圆孔的适度椭圆薄板的自由振动基频进行了分析．当薄板的内边界受弹性约束,外边界为自由,导出了自由振动基频的解析解．同时,利用ANSYS软件进行了数值模拟,通过经典边界条件下基频结果的对比,验证了基于本文理论解的计算结果的精确性．本方法可以有效用于处理具有曲线边界的薄板结构的自由振动问题．     

Spin-dependent thermoelectric effect and spin battery mechanism in triple quantum dots with Rashba spin-orbital interaction

We have studied spin-dependent thermoelectric transport through parallel triple quantum dots with Rashba spinorbital interaction(RSOI) embedded in an Aharonov-Bohm interferometer connected symmetrically to leads using nonequilibrium Green's function method in the linear response regime.Under the appropriate configuration of magnetic flux phase and RSOI phase,the spin figure of merit can be enhanced and is even larger than the charge figure of merit.In particular,the charge and spin thermopowers as functions of both the magnetic flux phase and the RSOI phase present quadruple-peak structures in the contour graphs.For some specific configuration of the two phases,the device can provide a mechanism that converts heat into a spin voltage when the charge thermopower vanishes while the spin thermopower is not zero,which is useful in realizing the thermal spin battery and inducing a pure spin current in the device.     

In-plane anisotropy in two-dimensional electron gas at LaAlO_3/SrTiO_3(110) interface

A systematic study of the two-dimensional electron gas at La AlO_3/SrTiO_3(110) interface reveals an anisotropy along two specific directions, [001] and 1ī0. The anisotropy becomes distinct for the interface prepared under high oxygen pressure with low carrier density. Angular dependence of magnetoresistance shows that the electron confinement is stronger along the 1ī0 direction. Gate-tunable magnetoresistance reveals a clear in-plane anisotropy of the spin–orbit coupling,and the spin relaxation mechanism along both directions belongs to D'yakonov–Perel'(DP) scenario. Moreover, in-plane anisotropic superconductivity is observed for the sample with high carrier density, the superconducting transition temperature is lower but the upper critical field is higher along the 1ī0 direction. This in-plane anisotropy could be ascribed to the anisotropic band structure along the two crystallographic directions.     

铁基超导体NdFeAsO0.82F0.18的涡旋晶格融化

在涡旋弹性理论和Lindemann判据的框架下,基于两个Lindemann系数的假设,研究了当磁场方向与各向异性轴垂直时铁基超导的涡旋晶格的融化相变.同时给出了未考虑和考虑层状钉扎势的情况下系统在两个方向的热涨落,以及相关的涡旋晶格融化线.     

Viscoelastic BISQ Model for Low-Permeability Sandstone with Clay

A modified BISQ （Blot/Squirt） model for wave propagation in low-permeability sandstone is developed by introducing the viscoelastic mechanism of a porous skeleton into Dvorkin＇s model. The linear viscoelasticity of the Kelvin Voigt constitutive law is employed to describe the stress-strain relation of a solid frame with clay while the ultrasonic waves propagate through the fluid-saturated sandstone. The phase velocity and attenuation of two p-waves are given based on the present BISQ model. The comparisons between numerical results and experimental data indicate that our viscoelastic model is more realistic and feasible for wave propagation in the low-permeability sandstone, especially with clay, than traditional BISQ models.     

单分散性CdSe纳米晶的合成——成核及其生长过程

 在氩气保护下,用三辛基亚磷酸和油酸分别作为Se和Cd的配位体,在260～300 ℃的十八烯溶液中合成了尺寸可控的CdSe纳米晶。该纳米晶不用进行进一步的提纯和尺寸分离就具有单分散性,其量子尺寸限域效应非常明显——吸收光谱的第一吸收峰峰位随着纳米晶的长大而发生红移;该纳米晶质量很高,具有很强的发光能力,其发射光谱对称的形状和合理的Stokes频移（13 nm）显示,该纳米晶的发光完全出自带隙,没有来自缺陷的发光。此外,实验结果表明,通过改变三辛基亚磷酸的浓度可以调节成核和生长的快慢,从而可以在不同的反应时间得到不同尺寸的单分散性CdSe纳米晶。     

Electronic transport through a periodic array of quantum-dot rings

Using the tight-binding approximation and the transfer matrix method, this paper studies the electronic transport properties through a periodic array of quantum-dot (QD) rings threaded by a magnetic flux. It demonstrates that the even--odd parity of the QD number in a single ring and the number of the QD rings in the array play a crucial role in the electron transmission. For a single QD ring, the resonance and antiresonance transmission depend not only on the applied magnetic flux but also on the difference between the number of QDs on the two arms of the ring. For an array of QD rings, the transmission properties are related not only to the even--odd parity of the number $N_{0}$ of QDs in the single ring but also to the even--odd parity of the ring number $N$ in the array. When the incident electron energy is aligned with the site energy, for the array of $N$ rings with $N_{0}={\rm odd}$ the antiresonance transmission cannot occur but the resonance transmission may occur and the transmission spectrum has $N$ resonance peaks ($N-1$ resonance peaks) in a period for $N={\rm odd}$ (for $N={\rm even}$). For the array of $N$ rings with $N_{0}={\rm even}$ the transmission properties depend on the flux threading the ring and the QD number on one arm of the ring. These results may be helpful in designing QD devices.