排序方式: 共有14条查询结果,搜索用时 15 毫秒
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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. 相似文献
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PET/PEN共混体系结构与性能研究进展 总被引:4,自引:0,他引:4
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. 相似文献
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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. 相似文献
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SOL-GEL法制备钛酸锶钡(BST)粉体 总被引:3,自引:0,他引:3
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. 相似文献
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Characterization of the N-polar GaN film grown on C-plane sapphire and misoriented C-plane sapphire substrates by MOCVD 下载免费PDF全文
Xiaotao Hu 《中国物理 B》2022,31(3):38103-038103
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. 相似文献
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亚氯酸盐-硫代硫酸盐非缓冲体系的动力学 总被引:11,自引:0,他引:11
研究了亚氯酸盐-硫代硫酸盐反应体系在非缓冲条件下的复杂动力学行为.结果发现,在开放体系中反应的pH值和Pt电位存在准周期振荡分叉和混合模式振荡分叉通向混沌的过程,且pH峰与Pt电位峰反相位.当与起始浓度比相对较小时,随着流速的逐渐升高,体系的pH值和Pt电位从简单的小振幅振荡(S)经过准周期振荡分叉到混沌,最后回到简单大振幅振荡(L);而当与起始浓度比相对较高时,随着流速的降低,体系的pH值和Pt电位出现LS1、LS2、LS3…LSn的混合模式振荡,并在每对(LSn、LSn+1)振荡区间发现了LSn、LSn+1随机出现的非周期振荡行为.运用硫价态变化的一般动力学模型,模拟出了反应体系的混合模式振荡及非周期振荡. 相似文献