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1.
Straight-chain aliphatic terr-amine N-oxides were found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields.The process for epoxidation by employing tri-n-butylamine N-oxide gave the best result in the reagent survey. 相似文献
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Zhihua Wang Jinshu Li Xiaole Liu Jianming Yang Xiaoquan Lu 《Analytical and bioanalytical chemistry》2013,405(8):2525-2533
A sensitive amperometric sensor for norfloxacin (NF) was introduced. The receptor layer was prepared by molecularly imprinted photopolymerization of acrylamide and trimethylolpropane trimethacrylate on the surface of a gold electrode. The binding mechanism of the molecularly imprinted polymer was explored by ultraviolet (UV) and infrared (IR) spectroscopy. The chemosensor was characterized by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance (EI), and scanning electron microscopy (SEM). The electrode prepared by photopolymerization has a better recognition ability to template molecules than that of electropolymerization and NIP. Some parameters affecting sensor response were optimized. Norfloxacin was detected by measurements of an amperometric i–t curve. The linear relationships between current and logarithmic concentration are obtained from 1.0?×?10?9 to 1.0?×?10?3?mol?L?1. The detection limit of the sensor was 1.0?×?10?10?mol?L?1. The proposed method is sensitive, simple, and cheap, and is applied to detect NF in human urine successfully. Figure
Amperometric i-t curves of MIPs electrode 相似文献
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以两个形状杂化分子(Shape Hybrid Molecules)为目标分子, 研究了它们在气液界面上形成Langmuir膜的过程和Langmuir-Blodgett (LB)膜的聚集态结构. 杂化分子是由Wells-Dawson型磷钨氧簇(Polyoxometalates, POMs)和T8型的倍半硅氧烷簇(Polyhedral Oligosilsesquioxane, POSS), 通过对苯二甲酸有机连接链(OL)用共价键构筑的具有杂化性质和哑铃形状的簇-簇杂化分子(POM-OL-POSS). 这两种杂化分子的差别在于POSS段中, 外围有机基团的尺寸不同. 在实验中, 采用Langmuir和LB膜技术, 了解POSS外围的七个取代基变化导致的分子尺寸变化对Langmuir膜形成过程和LB膜结构的影响. 采用Langmuir技术测定了表面压-平均分子面积(π-A)等温曲线和π-A循环等温曲线, 跟踪并研究了这两个杂化分子在水表面上形成Langmuir膜的过程. 实验结果表明, 两个杂化分子都表现出良好的两亲性, 从气相变化到固相的过程中, 杂化分子经历了从分散到集中的过程. 将这些膜转移到基片上, 得到单层的LB膜, 再利用原子力显微镜(AFM)和透射电子显微镜(TEM)研究了LB膜的表面形貌和聚集态结构. 由于POM段中含有钨和钒金属, 可以直接用TEM观察聚集态结构, 发现了在气-液和液-固相转变过程中, LB膜中杂化分子的聚集态结构都呈现涨落特征, 一种凝聚态物理中由相转变导致结构涨落的重要物理现象. 本研究获得的结果能够帮助我们以及这个领域的研究者们继续优化杂化分子的结构, 进一步构筑具有有序结构的膜和本体材料. 相似文献
4.
The acoustical wave propagator technique is applied to study the time-domain dynamic stress concentration in a two-dimensional flexible plate with a sharp change of section. As a wave packet approaches the plate discontinuity where the sharp change of thickness is introduced, the spatial interference patterns in the displacement of the plate and internal stresses vary with time. The constructive interference of stresses is referred to as time-domain stress concentration. The superposition of wave fronts of incident and reflected wave packets is used to explain the spatial distribution of the interference patterns. The increase of dynamic stress near the vicinity of the discontinuity boundary of the plate is studied as a function of time and the thickness ratio of the plates. 相似文献
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In situ variable temperature XRD (VT-XRD) measurements on the transformation of nano-precursors to LaNiO phases are presented. Experimental results showed that LaNiO3 and La2NiO4 phases were formed at ca. 700 °C via the reaction of La2O3 and NiO (from the initial nano-precursors), where a relatively low temperature of 700 °C was found for the synthesis of La2NiO4. The formation of La3Ni2O7 at higher temperature (up to 1150 °C) appeared to proceed through a further reaction of La2NiO4 with unreacted NiO, whilst the formation of La4Ni3O10 (at 1075 °C) proceeded via a further decomposition of LaNiO3. Although phase pure La3Ni2O7 and La4Ni3O10 were not directly obtained under the processing conditions herein, the results of this study allow for a better understanding of formation pathways, particularly for the higher order La-Ni-O phases. 相似文献
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Nonlinear Dynamics - In this paper, we investigate a general integrable three-component coupled nonlocal nonlinear Schrödinger system with the parity-time symmetry. The general Nth Darboux... 相似文献
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In this work, we propose a simple, sensitive and reliable assay for melamine in raw milk with dopamine-stabilized silver nanoparticles (AgNPs) as a colorimetric reader. Dopamine can reduce Ag(+) and functionalize the produced AgNPs to form monodispersed AgNPs. The coexisting melamine in reaction solution could bind dopamine through Michael addition and Schiff base reactions, which leads to the aggregation of AgNPs and induces a colorimetric response. The one-step assay is simple, rapid and highly sensitive. The color-change is quantitatively correlated with the concentration of melamine in the range of 10 ppb to 1.26 ppm, which is below the safety limit in China (1.0 ppm) and EU (2.0 ppm). The coexisting substances including phenylalanine, dl-leucine, l-glutamate, sulfanilic acid, Mg(2+), galactose, lysine, urea and glucose do not affect the determination of melamine. The colorimetric sensor can be used for rapid monitoring of raw milk quality. 相似文献
9.
Xiaole Weng Paul Boldrin Isaac Abrahams Suela Kellici 《Journal of solid state chemistry》2008,181(5):1123-1132
A new direct route for the “bottom up” syntheses of phases in the Lan+1NinO3n+1 series (n=1, 2, 3 and ∞) has been achieved via single-step heat treatments of nanosized co-crystallized precursors. The co-crystallized precursors were prepared using a continuous hydrothermal flow synthesis system that uses a superheated water flow at ca. 400 °C and 24.1 MPa to produce nanoparticulate slurries. Overall, a significant reduction in time and number of steps for the syntheses of La3Ni2O7 and La4Ni3O10 was achieved compared with more conventional synthesis methods, which typically require multiple homogenization and reheating steps over several days. 相似文献
10.
"Microfluidic drifting"--implementing three-dimensional hydrodynamic focusing with a single-layer planar microfluidic device 总被引:2,自引:0,他引:2
We introduce a novel fluid manipulation technique named "microfluidic drifting" to enable three-dimensional (3D) hydrodynamic focusing with a simple single-layer planar microfluidic device. 相似文献