相干态与压缩态迭加的量子特性

基于量子力学基本理论,构造了一个由相干态与单模压缩态构成的新迭加态:|φ>=N(|α> eiψ|β>g);详细讨论了其压缩效应和光子数反聚束效应,发现该迭加态呈现出多样的量子特性.在按类似奇偶相干态的方式迭加时,迭加态具有奇偶相干态和压缩奇偶相干态的某些特性.作为特例,当压缩因子为0时,可以得到奇偶相干态和相干态.     

固相萃取-液相色谱测定复杂基质蔬菜中9种烟碱类残留

建立了韭菜、洋葱、大蒜等复杂基质蔬菜样品中呋虫胺、烯啶虫胺、氟啶虫酰胺、噻虫嗪、吡虫啉、噻虫胺、氯噻啉、啶虫脒、噻虫啉9种烟碱类农药残留的液相色谱检测方法.对比了几种常用溶剂的提取效率以及固相萃取材料对韭菜、洋葱样品中干扰基质的去除效果.研究结果表明,样品经微波处理后,用乙腈提取,Envi-Carb/PSA固相萃取柱净...     

核酸功能化稀土基纳米材料在生物检测中的应用

体内一些生物分子和离子的水平通常与细胞、组织、器官等结构和功能的变化相关,从而直接影响到疾病的预防、诊断和治疗,因此对体内这些物质的生物检测在医疗和健康领域具有重要的意义.基于稀土基纳米材料构建的纳米荧光探针具有灵敏度高、简单高效、抗干扰能力强等优点,在生物检测方面具有巨大的潜力.对稀土基纳米材料的核酸功能化能够进一步为纳米荧光探针提供更好的特异性识别能力和生物相容性,从而增强其在复杂样品中的生物检测能力.本综述总结了核酸功能化的稀土基纳米材料作为纳米荧光探针在生物检测领域的研究进展,简要介绍了其主要种类和性能、检测机理及检测物质,最后对该领域面临的挑战及未来的发展方向进行了展望.     

PET/PEN共混体系结构与性能研究进展

综述了国内外PET/PEN共混体系的研究进展,重点论述了PET/PEN共混体系的结晶性能相容性酯交换影响因素、结晶动力学,并对其应用前景做了展望.     

SOL-GEL法制备钛酸锶钡(BST)粉体

Ba1-x SrxTiO3 (BST) powders were fabricated by sol-gel process by using strontium carbonate for the substitution of strontium acetate. Barium acetate, strontium carbonate and titanium-tetrabutoxide were used as raw materials. The BST gel was studied by thermal analysis techniques, the physical structure of the BST powders was measured by XRD and the grain size was measured. The results showed that the powders possess a single perovskite phase after 700℃ and the ideal powder size even after 800℃ calcining. This indicated that the powder can be used for BST ceramics and the fabrication of the sol-gel derived BST can be carried out well by using carbonate as the starting materials.     

Determination of Active Ingredients of Hawthorn by Capillary Electrophoresis with Electrochemical Detection

A method based on capillary electrophoresis with electrochemical detection has been developed for the separa-tion and determination of epicatechin,kaempferol,chlorogenic acid,4-hydroxybenzoic acid,quercetin and proto-catechuic acid in hawthorn for the first time.The effects of working electrode potential,pH and concentration ofrunning buffer,separation voltage and injection time on CE-ED were investigated.Under the optimum conditions,the analytes could be separated in a 60 mmol·L~(-1) borate buffer(pH 8.7)within 21 min.A 300 μm diameter carbondisk electrode has a good response at 0.95 V(vs.SCE)for all analytes.The response was linear over three ordersof magnitude with detection limits(S/N=3)ranging from 3×10~(-8) to 2×10~(-7) g·mL~(-1) for the analytes.The methodhas been successfully applied to the analysis of real sample,with satisfactory results.     

Characterization of the N-polar GaN film grown on C-plane sapphire and misoriented C-plane sapphire substrates by MOCVD

Gallium nitride (GaN) thin film of the nitrogen polarity (N-polar) was grown on C-plane sapphire and misoriented C-plane sapphire substrates respectively by metal-organic chemical vapor deposition (MOCVD). The misorientation angle is off-axis from C-plane toward M-plane of the substrates, and the angle is 2° and 4° respectively. The nitrogen polarity was confirmed by examining the images of the scanning electron microscope before and after the wet etching in potassium hydroxide (KOH) solution. The morphology was studied by the optical microscope and atomic force microscope. The crystalline quality was characterized by the x-ray diffraction. The lateral coherence length, the tilt angle, the vertical coherence length, and the vertical lattice-strain were acquired using the pseudo-Voigt function to fit the x-ray diffraction curves and then calculating with four empirical formulae. The lateral coherence length increases with the misorientation angle, because higher step density and shorter distance between adjacent steps can lead to larger lateral coherence length. The tilt angle increases with the misorientation angle, which means that the misoriented substrate can degrade the identity of crystal orientation of the N-polar GaN film. The vertical lattice-strain decreases with the misorientation angle. The vertical coherence length does not change a lot as the misorientation angle increases and this value of all samples is close to the nominal thickness of the N-polar GaN layer. This study helps to understand the influence of the misorientation angle of misoriented C-plane sapphire on the morphology, the crystalline quality, and the microstructure of N-polar GaN films.     

Demonstration of Quantum Entanglement Control Using Nuclear Magnetic Resonance

With the two forms of the quantum entanglement control, the quantum entanglement swapping and preservation are demonstrated in a three-qubit nuclear magnetic resonance quantum computer. The pseudopure state is prepared to represent the quantum entangled states through macroscopic signals. Entanglement swapping is directly realized by a swap operation. By controlling the interactions between the system and its environment,we can preserve an initial entangled state for a longer time. The experimental results are in agreement with the experiment.     

基于表面优先型相变过程构建TiO_2(B)/锐钛矿异相结纳米纤维及其光催化性能（英文）

近年来,随着光催化研究的逐渐深入,人们发现有效的电荷分离往往是提高半导体光催化材料活性的关键步骤.其中,在多晶相半导体材料中构建异相结结构是提高其活性的最有效途径之一.在TiO_2四种稳定晶相中,Ti O2(B)是发现最晚且研究较少的,并且目前对它的研究主要集中于锂离子电池方面,而在光催化领域中研究较少.然而,该材料特殊的晶相结构带来的各向异性和较大的比表面积都表明其在光催化领域同样具有潜在应用前景.本文通过三步合成法,包括水热过程、离子交换、退火过程,研究了TiO_2(B)向锐钛矿转变的相变过程,同时构建了具有TiO_2(B)/锐钛矿异相结结构的纳米线.在材料退火过程中,通过X射线衍射(XRD)和表面灵敏的紫外拉曼光谱(UV-Raman)分别监测了样品体相和表面相的晶相结构变化过程.发现了XRD与UV-Raman结果的不同步性.同时,通过对样品扫描电镜和透射电镜的形貌表征可知,TiO_2(B)纳米线在退火过程中部分结构发生坍塌,且逐渐转化成锐钛矿相,而相变过程很可能首先发生在坍塌结构处.高分辨电镜结果表明,纳米线中同时存在着TiO_2(B)结构和锐钛矿结构,并形成很好的异相结.根据相结构变化和形貌观察结果,我们推测TiO_2(B)向锐钛矿转变过程为表面优先型的相变过程,即材料表面相先于体相先发生相变过程,由此得到的材料表面相含有较多的锐钛矿,而体相中含有较多的TiO_2(B).为了验证构建的异相结材料的光催化活性,采用光催化产氢和降解污染物双重反应对样品进行了表征.结果发现,单独的TiO_2(B)材料活性较锐钛矿材料相差较多,但其混相结构能较大幅度地提高光催化活性.其中,通过逐渐退火过程形成的体相为24%的TiO_2(B)、表面为100%的锐钛矿相的催化剂活性最高,其产氢活性可达4.82 mmol/(h?g),降解污染物反应速率常数为0.0402 min~(-1).采用光电流测试、电化学阻抗和荧光光谱表征了材料在光催化过程中的载流子动力学行为.结果表明,最优活性的催化剂中体相的异相结结构对光生电荷的分离、传输都起到良好地促进作用,而表面的锐钛矿相主要负责高活性的表面反应,二者共同对高活性的光催化反应起到推动作用.