Single-particle plasmon resonance spectroscopy of phase transition in vanadium dioxide

We demonstrate thermally controlled plasmon resonance modulation of single gold nanoparticles on vanadium dioxide thin films by performing dark-field spectroscopy measurements at different temperatures. The plasmon resonance of the nanoparticles exhibits a significant blueshift in the visible range when the vanadium dioxide film undergoes its insulator-to-metal phase transition around 67 °C. More importantly, the resonance shift shows a clear hysteresis, mirroring the behavior of the vanadium dioxide film. At a fixed wavelength, the scattering intensity of Au particles also shows a hysteretic behavior decorated with an overshoot before (after) the insulator-metal (metal-insulator) phase transition of the vanadium dioxide film, suggesting that the nanoparticle is probing local variations in the phase transition.     

A cascade reaction consisting of Pictet-Spengler-type cyclization and Smiles rearrangement: application to the synthesis of novel pyrrole-fused dihydropteridines

[reaction: see text] Tandem Pictet-Spengler-type cyclization and Smiles rearrangement have been discovered in the synthesis of pyrimidine-fused heterocycles. The reaction of 4-chloro-5-pyrrol-1-ylpyrimidine amino aldehyde with an amine under an acidic condition yielded the Pictet-Spengler-type cyclization product diazepine, which readily underwent Smiles rearrangement to give a novel pyrrolo[1,2-f]pteridine derivative.     

超声在固体火箭发动机无损检测中的应用

在固体火箭发动机的研制中，无损检测技术非常重要。本文介绍了一些主要的超声检测方法及其应用。脉冲多次反射法用于检测固体火箭发动机壳体与衬层之间的粘结质量。特性参数和扫频超声法以多层介质理论为基础，用于检测固体火箭发动机的深层粘结质量。     

Positive Radial Solutions of Some Nonlinear Partial Differential Equations

We consider Dirichlet boundary value problems for a class of nonlinear ordinary differential equations motivated by the study of radial solutions of equations which are perturbations of the p-Laplacian.     

一种基于HTTP的Internet文件存储系统的设计和实现

利用网络进行文件管理，尤其是利用范围最广的Internet网络进行存储管理，能极大地方便和满足用户文件存储管理的需要．论述了一种基于HTTP的Internet文件存储系统的设计和实现．     

抛物方程时间连续有限元全离散格式的超收敛性

利用张量积分解和时间方向单元正交分解,证明了线性抛物型方程的时间连续全离散有限元在单元节点和内部的特征点的超收敛性.并用连续有限元计算了非线性Schrodinger方程,验证了能量的守恒性.计算结果与理论相吻合.     

2-氟-6-氯甲苯氨氧化法制备2-氟-6-氯苯腈初探

以2—氟—6—氯甲苯(CFT)为原料，采用氨氧化法一步制得了2—氟—6—氯苯睛．通过实验筛选到以钒、磷为主要成分的5组分F52号催化剂．使用该催化剂进行2—氟—6—氯甲苯氨氧化反应的最佳工艺条件：温度为380℃，反应物摩尔比n(CFT)：n(NH3)：n(空气)＝1：6：25．在此条件下，2—氟—6—氯甲苯的转化率为98．99％，2—氟—6—氯苯睛的产率(摩尔)为71．47％，选择性为72．20％．经气相色谱分析，产品纯度高于99％．     

一般波包在均匀场中的运动

求出了一般波包的中心和宽度在一维均匀场中的变化规律，波包的中心遵循经典粒子的运动规律，宽度的平方则以时间的二次函数增长，但动量空间的相应波包却保持其宽度不变，特别是平面波在运动过程中仍保持为平面波，对Gauss波包，求出了波函数随时间变化的显式，验证了一般结论。     

Riboflavin Sensitized Photopolymer Materials for Holographic Storage

Riboflavin is employed as the photosensitizer of a novel photopolymer material for holographic recording. This material has a broad absorption spectrum range （more than 200nm） due to the addition of this dye. The experimental results show that our material has high diffraction efficiency and large refractive index modulation. The maximum diffraction efficiency of the photopolymer is about 56%. The digital data pages are stored in this medium and the reconstructed data page has a good fidelity, with the bit-error-ratio of about 1.8 × 10^-4. It is found that the photopolymer material is suitable for high-density volume holographic digital storage.