四角晶相HfO2(001)表面原子和电子结构研究

采用基于第一性原理的密度泛函理论研究了四角晶相二氧化铪(t-HfO₂)体相及 其(001)表面的原子几何与电子结构.理论计算结果表明，t-HfO₂(001)表面不会 产生重构现象.与体相电子结构相比, t-HfO₂(001)表面态密度明显高于体相态 密度.其次，表面原子的态密度更靠近费米能级(E_F)，价带往低能量处移动，并 有表面态产生.计算结果表明了t-HfO₂表面禁带宽度明显低于体相的禁带宽度. t-HfO₂(001)的表面态产生以及表面禁带宽度减小是由于Hf原子与O原子的配位 数减少，表面原子周围的环境发生变化而引起的. 关键词： 密度泛函理论 2(001)')" href="#">t-HfO₂(001) 表面电子结构     

Photoinduced Intramolecular Charge Transfer in Donor-acceptor Dyad and Donor-bridge-acceptor Triad

在fullerene-PBTDP-TPA三体体系中的光诱导的分子内电荷转移的实验基础上,分别利用密度泛函理论和含时密度泛函理论以及结合二维、三维实空分析方法对fullerene、PBTDP-TPA二体以及fullerene-PBTDP-TPA三体的基态和激发态的性质进行了理论研究．二维定点表象揭示了激发情况下电子和空穴的相干情况．三维跃迁矩阵展示了跃迁偶极矩的方向和强度,而且三维电荷差密度给出了光诱导的分子内电荷转移的方向和结果．同时,用二维和三维表象的方法对fullerene-PBTDP-TPA三体中光诱导的分子内电荷转移过程进行了验证,揭示了在给予者-桥-接收者三体分子体系中分子内激发时电荷转移的机制．除此之外,还发现直接从给予者到接收者超交换的分子内电荷转移极大地促进了给予者-桥-接收者三体分子体系内的电荷转移．     

Z箍缩丝阵负载区域的似稳态磁场分布

 将负载区域的电流（丝阵电流、阴极板电流、阳极板电流和回流柱电流）离散成电流线或电流面等电流微元,根据毕奥-萨伐尔定律,计算所有电流微元在指定场点的磁场,再通过叠加给出该点的总磁场。研究结果发现:在丝阵外围区域,仅由丝阵电流所产生的磁场偏离无限长直导线磁场公式的值,但全部电流所产生的总磁场与公式给出的值很接近。同时,研究了不同负载结构参数下的磁场分布,结果表明：增加丝根数有助于减小单根丝表面的局部磁场,改善丝阵外围磁场分布的均匀性。     

One-step synthesis ofα,β-unsaturated arylsulfones by a novel multicomponent reaction of aromatic aldehydes,chloroacetonitrile, benzenesulfinic acid sodium salt

A new and green method for the synthesis of α,β-unsaturated arylsulfones had been achieved through the condensation of aromatic aldehydes,chloroacetonitrile,benzenesulfinic acid sodium salt in the presence of l-butyl-3-methyl imidazolium hydroxide([bmim]OH) in EtOH under reflux.The ionic liquid was recovered and recycled for subsequent reactions.The advantages of this protocol were non-toxic,easy work-up and good yields.     

Why calcium inhibits magnesium-dependent enzyme phosphoserine phosphatase? A theoretical study

Mechanisms for the formation of the Schiff base from acetaldehyde and butylamine, glycine and phosphatidylethanolamine based on Dmol3/DFT calculations were realized. For the case of phosphatidylethanolamine, calculations were done under periodic boundary conditions, in an amine-phospholipid monolayer model with two molecules of phosphatidylethanolamine by cell. All models contained explicit aqueous solvent. In the three cases, a neutral amino group is used to model the nucleophilic attack on the carbonyl group of acetaldehyde, and water molecules form hydrogen bond networks. These networks were involved in the reactions by performing as proton-transfer carriers, important in some steps of reactions, and stabilizing reaction intermediates. In all the studied reactions, they take place in two steps, namely: (1) formation of a carbinolamine and (2) its dehydration to the Schiff base, being the dehydration the rate-determining step of the process, consistent with available experimental evidence for similar reactions. The main difference between the studied reactions is found in the value for relative free energy for the intermediates and transition states in the second step; these values are lower in the cases of glycine and phosphatidylethanolamine in comparison with butylamine, due the influence of their molecular environments. Based on the results, the aminophospholipid surface environment and carboxylic group of glycine may boost Schiff base formation via a neighboring catalyst effect.     

部分相干径向偏振光束传输中相干性研究

根据广义惠更斯理论及相干偏振统一理论, 研究部分相干径向偏振光束在自由空间中传输时, 不同参考点处复相干度随传输距离的变化规律. 研究表明, 部分相干径向偏振光束在自由空间中传输, 不同参考点处, 复相干度模值随距离的变化规律有所差别. 当参考点位于原点时, 随着传输距离增大, μ_xx模值及μ_xy模值分布形式不变, 分布范围增大; 当参考点位于x轴上时, μ_xx模值由单峰值向三峰两谷对称形式演化, μ_xy模值由单侧两峰向四峰四谷对称形式演化, 完成演化所需传输距离与参考点距离x轴中心的远近有关, 参考点距离x轴中心越近, 完成演化所需的传输距离越短; 当参考点位于y轴时, 随着距离增大, μ_xx模值分布形式不变, 分布范围增大, μ_xy模值由上侧两峰向四峰四谷对称形式演化, 演化所需传输距离与参考点距y轴中心远近有关, 参考点距y轴中心越近, 完成演化所需的传输距离越短; 当参考点位于其他位置时(非特殊位置), μ_xx模值及μ_xy 模值分布规律, 遵从各自参考点在x轴, y轴上的分布规律的结合即参考点位于其他位置时, μ_xx模值及μ_xy模值分别随距离变化逐渐演化成三峰结构、四峰结构.     

压印光刻中的两步对正技术

压印光刻中套刻需要粗、精两级对正.实验采用一对斜纹结构光栅作为对正标记.利用物镜组观察光栅标记图像的边界特征进行粗对正,其准确度在精对正信号的捕捉范围内;利用光电接收器件阵列组合接收光栅莫尔信号,在莫尔信号的线区进行精对正.由于线性区的斜率大, 精对正过程中得到相应x,y方向的对正误差信号灵敏度高,利用高灵敏度对正误差信号作为控制系统的驱动信号,对承片台进行驱动定位,实现精对正.最终使X,Y方向上的重复对正准确度分别达到了± 21 nm(± 3σ)和±24 nm(± 3σ).     

Synthesis and properties of Au-Fe3O4 and Ag-Fe3O4 heterodimeric nanoparticles

Monodisperse Au-Fe 3 O 4 heterodimeric nanoparticles (NPs) were prepared by injecting precursors into a hot reaction solution.The size of Au and Fe 3 O 4 particles can be controlled by changing the injection temperature.UV-Vis spectra show that the surface plasma resonance band of Au-Fe 3 O 4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size.The as-prepared heterodimeric Au-Fe 3 O 4 NPs exhibited superparamagnetic properties at room temperature.The Ag-Fe 3 O 4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO 3 as precursor instead of HAuCl 4.It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.