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231.
Jun Wang Tianjin Zhang Hongying Xia Junhuai Xiang Wenkui Li Shuwang Duo 《Journal of Sol-Gel Science and Technology》2008,47(1):102-106
Compositionally graded Ba1−x
Sr
x
TiO3 (BST) (0 ≤ x ≤ 0.4) thin films were fabricated on Pt/Ti/SiO2/Si and YSZ/Pt/Ti/SiO2/Si substrates by a modified sol–gel technique. The YSZ buffer layer was prepared by RF magnetron sputtering. The microstructure
of the graded BST films was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force
microscopy (AFM). The results showed that all the films have uniform and crack-free surface with a perovskite structure. The
graded BST film with an YSZ buffer layer has larger dielectric constant and lower dielectric loss. The leakage current density
of the graded BST film with an YSZ buffer layer lowers two orders than the film without buffer layer. The improved electric
properties of the graded films with an YSZ buffer layer was attributed to the YSZ buffer layer act as an excellent seeding
layer to enhance the graded BST film growth. 相似文献
232.
Jing Miao Guohua Chen Congjie Gao Cunguo Lin Duo Wang Mingkun Sun 《Journal of membrane science》2006,280(1-2):478-484
N,O-carboxymethyl chitosan (NOCC) composite nanofiltration membranes having a polysulfone (PS) UF membrane as the substrate were prepared using a method of coating and cross-linking, in which a glutaraldehyde (GA) aqueous solution was used as the cross-linking agent. Attenuated total reflection infrared spectroscopy (ATR-IR) was employed to characterize the resulting membrane. The effects of the composition of the casting solution of the active layer, the concentration of the cross-linking agent, and the membrane preparation techniques on the performance of the composite membrane were investigated. At 13–15 °C and 0.40 MPa the rejections of the resulting membrane to Na2SO4 and NaCl solutions (1000 mg L−1) were 92.7 and 30.2%, respectively, and the permeate fluxes were 3.0 and 5.1 kg m−2 h−1, respectively. The rejection of this kind of membrane to the electrolyte solutions decreased in the order of Na2SO4, NaCl, MgSO4, and MgCl2. This suggests that the membrane active layer acquires a negative surface charge distribution by the adsorption of anions from the electrolyte solution and this charge distribution mainly determines the membrane performance. 相似文献
233.
Yuan Gong Xin‐Yi Huang Jian‐Fei Liu Dong Pei Wen‐Da Duan Xia Zhang Xiao Sun Duo‐Long Di 《Journal of separation science》2020,43(14):2949-2958
An efficient combination strategy based on high‐speed shear dispersing emulsifier technique and high‐performance countercurrent chromatography was developed for on‐line extraction and isolation of carotenoids from the fruits of Lycium barbarum. In this work, the high‐speed shear dispersing emulsifier technique has been employed to extract crude extracts using the upper phase of high‐performance countercurrent chromatography solvent system composed of n‐hexane?dichloromethane?acetonitrile (10:4:6.5, v/v) as the extraction solvent. At the separation stage, the high‐performance counter‐current chromatography process adopts elution–extrusion mode and the upper phase of the solvent system as stationary phase (reverse‐phase mode). As a result, three compounds including zeaxanthin, zeaxanthin monopalmitate, and zeaxanthin dipalmitate with purities of 89, 90, and 93% were successfully obtained in one extraction‐separation operation within 120 min. The targeted compounds were analyzed and identified by high‐performance liquid chromatography, mass spectrometry, and NMR spectroscopy. The results indicated that the present on‐line combination method could serve as a simple, rapid, and effective way to achieve weak polar and unstable compounds from natural products. 相似文献
234.
Yaohui Lv Hong Liu Zhen wang Lujiang Hao Jing Liu Yangmin Wang Guojun Du Duo Liu Jie Zhan Jiyang Wang 《先进技术聚合物》2008,19(11):1455-1460
Silver nanoparticles were covalently coated on a glass surface by overnight exposure of the glass substrate to nanoparticle solutions, using 3‐aminopropyltriethoxysilane (APTES) as a coupling agent. Washing and air‐drying yield a uniformly coated glass substrate, which can be used as a material capable of killing harmful microorganisms in food industry. Nanoparticles are stable on the glass surface and are not washed away by water; they even remain on the glass surface under short‐term ultrasonic irradiation. The morphology of silver nanoparticles on the glass substrate was characterized by scanning electron microscope (SEM). The existence of Ag nanoparticles on the substrate was also confirmed by ultraviolet‐visible (UV–Vis) spectroscopy. Fourier transform infrared (FT‐IR) measurement shows that the connection is based on covalent bonds between silver nanoparticle surface/APTES molecules. Combining the effects of low cost and effectiveness in prohibiting the growth of Escherichia coli, such materials are expected to be used as antibacterial coatings, which may have large potential applications in food industry. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
235.
A method was developed for simultaneous determination of 5'-monophosphate nucleotides, adenosine 5'-monophosphate, cytidine 5'-monophosphate, guanosine 5'-monophosphate, inosine 5'-monophosphate, and uridine 5'-monophosphate in infant formulas by high-performance liquid chromatography-mass spectrometry equipped with electrospray ionization source. The complete chromatographic separation of five nucleotides was achieved through a Symmetry C(18) column, after a binary gradient elution with water containing 0.1% formic acid and acetonitrile as mobile phase. The multi-reaction monitoring mode was applied for tandem mass spectrometry analysis. The established method was further validated by determining the linearity (R(2) > 0.999), recovery (92.0-105.0%), and precision (relative standard deviation ≤6.97%). To verify the applicability of the method, thirty commercially available infant formulas were randomly purchased from the supermarkets in Hangzhou, China, and then analyzed. The results showed that the developed method is validated, sensitive, and reliable for quantitation of nucleotides in infant formulas. 相似文献
236.
通过两步法先在泡沫镍(nickel foam,NF)上原位生长Co金属有机骨架(Co metal-organic framework,Co-MOF)纳米片阵列,再浸入不同浓度Ni2+离子溶液刻蚀Co-MOF纳米片,在NF表面得到NiCo水滑石(NiCo layered double hydroxide,NiCo-LDH)。NiCo-LDH/NF继承了Co-MOF纳米片结构形成一级纳米片阵列,并在一级纳米片表面形成次级纳米片褶皱。在2 mmol Ni(NO3)2·6H2O溶液中刻蚀得到的NiCo-LDH/NF表现出高容量、高倍率性能,在电流密度为5 mA·cm-2时比电容为7 764.5 mF·cm-2,电流密度为20 mA·cm-2时比电容为6 098.2 mF·cm-2,容量保持率为78.5%,在20 A·g-1电流密度下经过5 000次长循环后,容量保持率为85.9%。与活性炭组装的混合电容器达到38.9 Wh·kg-1的最大能量密度和8 000.0 W·kg-1的最大功率密度。 相似文献
237.
The first total synthesis of paecilodepsipeptide A is reported.A convergent,flexible strategy employing peptide chemistry and culminating in macrolactamisation is described.The previously reported structure of compound is confirmed. 相似文献
238.
Hui Huang Jian‐Fang Gao Ling‐Hua Cao Duo‐Zhi Wang Jian‐Bin Zhang Shu‐Bao Zhou Yu‐Qiang Zhou 《中国化学会会志》2009,56(2):419-424
A series of novel thioglycoside derivatives containing 4(3H)‐quinazolinone was designed and synthesized from 2‐chloromethyl‐quinazolin‐4(3H)‐ones and 1‐thioglycose. Several 2‐chloromethyl‐quinazolin‐4(3H)‐ones were synthesized on refluxing with 2‐(chloroacetylamino)‐benzoic acid and arylamines in acetonitrile. All of the novel compounds were characterized by IR, 1H NMR spectra and elemental analysis. The structures of compounds 7b, 8b and 8c have been determined by X‐ray diffraction analysis. 相似文献
239.
Two novel complexes [Cu L 2(MeOH)] ( 1 )and [Ag2 L (H L )2(MeOH)] ( 2 ) ( L = 5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐carboxylic acid) were synthesized and characterized by elemental analysis, IR and X‐ray diffraction. Complex 1 is a mononuclear structure; the molecules were assembled into an infinite 2–D supramolecular by the C–H···O weak interactions. Complex 2 is a centrosymmetric dinuclear structure with bis(unidentate) carboxylato co‐ordination mode, and the molecules were assembled into 2–D layers by C–H···O and O–H···O weak interactions. 相似文献
240.
离子选择性电极测定溶液中Br-时去除Cl-的干扰 总被引:2,自引:0,他引:2
本文研究了用离子选择性电极法测定溶液中的Br-时,共存离子Cl-在5.0×10-5~1.0×10-2mol/L浓度范围内的干扰情况。同时,应用Matlab建立线性回归方程用于实际分析,取得满意结果。 相似文献