共查询到20条相似文献,搜索用时 24 毫秒
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Baidakova M. V. Germanov N. A. Golyandin S. N. Kompan M. E. Mochalov S. V. Nashchekin A. V. Nevedomskii V. N. Pul’nev S. A. Rabchinskii M. K. Ulin V. P. Ulin N. V. 《Technical Physics》2019,64(6):884-892
Technical Physics - It was shown that the interaction of silver cations in alkaline aqueous solutions with various kinds of silicates, regardless of their chemical and aggregation state, leads to... 相似文献
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O. V. Istomina S. K. Evstropiev E. V. Kolobkova A. O. Trofimov 《Optics and Spectroscopy》2018,124(6):774-778
Photolysis of Chicago Sky Blue diazo dye in aqueous solutions and films containing zinc and silver oxides is studied. The presence of zinc and silver nitrates in aqueous solutions of this dye considerably increase the rate of its photolysis under UV irradiation. ZnO and ZnO:Ag oxide films and composite coatings with zinc and silver nitrates also considerably affect the photolysis of Chicago Sky Blue diazo dye. 相似文献
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Evgenia Vaganova Cornelia Damm Gunter Israel Shlomo Yitzchaik 《Journal of fluorescence》2002,12(2):219-224
We have found that photoinduced pyridine ring cleavage-closure occurs in polymeric viscous solution, because in certain polymer solutions, pyridine can serve as a photo-modulated crosslinker. We suggest this reaction as a way to control a polymer's optical properties. Irradiation of the system: poly(4-vinyl pyridine)/pyridine/water with 250-nm wavelength range leads to the appearance of a new absorption band centered at 360 nm, new red-shifted emission, and HOMO-LUMO band gap changes. The subsequent irradiation with 360 nm (the new absorption band maximum) leads to reversion almost to the initial stage. A main active product of the photoreaction is aldehyde enamine, which has two active groups: primary amine and aldehyde, which can associate with the polymer molecules to form a physical crosslinked supramolecular structure. We evaluated the activation energy of the pyridine ring cleavage and back reaction depending on the polymer/pyridine/water ratio and by changing the polymer structure. The activation energy of pyridine's ring cleavage in viscous polymeric solutions is in the range of 0.6–3.2 Kcal/mol. The activation energy of the back reaction is significantly lower and is in the range of 0.05–0.15Kcal/mole. 相似文献
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采用柠檬酸三钠化学还原法制备球形Ag纳米粒子溶胶,并用高压球形氙灯对球形Ag纳米粒子溶胶进行光诱导实验.利用透射电子显微镜、紫外-可见吸收光谱研究了不同光照时间下的银胶纳米粒子的光谱特性和表面形貌,并以结晶紫为探针分子测量了银胶纳米粒子的表面增强喇曼散射光谱.实验结果表明:随着光照时间的增多,Ag纳米粒子溶胶颜色变化显著;紫外-可见吸收光谱吸收峰从单一峰渐渐显示出多个峰;透射电子显微镜图显示Ag纳米粒子由球形逐渐转变成片状三角形银纳米粒子、截角的片状三角形银纳米粒子;表面增强喇曼散射的增强效应随着光照时间的变化先逐渐增大,然后逐渐减小. 相似文献
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Dzhimak S. S. Shashkov D. I. Malyshko V. V. Moiseev A. V. Kopytov G. F. 《Russian Physics Journal》2021,64(6):1033-1038
Russian Physics Journal - A study was carried out of the effect of 10-fold cyclic freezing (down to –37°C) on the formation of nanostructures containing silver on the surfaces of a... 相似文献
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Mazing D. S. Korepanov O. A. Aleksandrova O. A. Moshnikov V. A. 《Optics and Spectroscopy》2018,125(5):773-776
Optics and Spectroscopy - Colloidal quantum dots (QDs) of AgInS2 and CuInS2 and corresponding core–shell structures were synthesized in aqueous solution using L-Glutathione and sodium citrate... 相似文献
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The surface-enhanced Raman scatterihg (SERS) spectra of human gallstones is investigated. Complicated Raman bands were due to multiple components that include bilirubin, bilirubinate salts, cholesterol, fatty salts and proteins. The results suggest that besides bilirubin and cholesterol, fatty salts and proteins may play an important role in the formation of gallstone. The experimental data supply an useful information for the research of the formation mechanism of gallstones. 相似文献
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Investigation of Surface-Enhanced Raman Spectra of Human Gallstones on Colloidal Silver 总被引:1,自引:0,他引:1
LIU Gang XING Da TAN Shici 《Chinese Journal of Lasers》2000,9(5):439-444
1 Introduction Gallstoneisacommonandfrequently occurringdisease .Atpresent ,therearenoeffectivedrugstotreatthedisease .Thetreatmentofgallstonesusuallycomprisestheremovalofbothgallstonesandgallbladderbysurgery .Gallstonescanbeclassifiedintothreetypesdepen… 相似文献
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Clyde Midelet Martinus H. V. Werts 《Particle & Particle Systems Characterization》2020,37(10):2000187
Optical spectroscopic techniques (e.g., extinction, scattering, and fluorescence spectroscopies) are important for the analysis of colloidal solutions of nanoparticles (NPs). They are routinely applied to plasmonic and quantum-dot NP samples assuming that these contain a single population of particles with modest size and shape dispersity. However, these spectroscopic techniques become less effective when the sample is a mixture of particles with different sizes, shapes, or composition. Here, an original microfluidic method is proposed for the optical spectroscopic analysis of colloidal NP solutions that combines periodic trapping of NPs by dielectrophoresis (DEP) with in situ optical extinction spectroscopy. The periodic trapping leads to modulation of the continuously monitored optical spectrum depending on the DEP properties of the NPs. DEP-modulated spectroscopy is demonstrated using colloidal gold NPs as small as 40 nm diameter. It is found that the DEP modulation is significantly enhanced when employing suitable microfluidic flow over a multielectrode array. Finally, it is shown that the method can identify and characterize the NP species simultaneously present in a mixture of 40 and 80 nm gold NPs, opening the way toward optical spectroscopic analysis of higher complexity NP mixtures through the combination of the DEP-modulated spectroscopy with chemometric methods. 相似文献
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Balogh Lajos Valluzzi Regina Laverdure Kenneth S. Gido Samuel P. Hagnauer Gary L. Tomalia Donald A. 《Journal of nanoparticle research》1999,1(3):353-368
Structural types of dendrimer nanocomposites have been studied and the respective formation mechanisms have been described, with illustration of nanocomposites formed from poly(amidoamine) PAMAM dendrimers and zerovalent metals, such as gold and silver. Structure of {(Au(0))n–PAMAM} and {(Ag(0))n–PAMAM} gold and silver dendrimer nanocomposites was found to be the function of the dendrimer structure and surface groups as well as the formation mechanism and the chemistry involved. Three different types of single nanocomposite architectures have been identified, such as internal (I), external (E) and mixed (M) type nanocomposites. Both the organic and inorganic phase could form nanosized pseudo-continuous phases while the other components are dispersed at the molecular or atomic level either in the interior or on the surface of the template/container. Single units of these nanocomposites may be used as building blocks in the synthesis of nanostructured materials. 相似文献
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SERS活性体系中光吸收带电磁和化学增强机制归属的认证研究方炎王四海(首都师范大学综合技术研究所,北京100037)AssignmentofEMandCTEnhancementsonOpticalAbsorptionSpectraofColoidal... 相似文献
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本文通过湿法化学还原法合成了平均粒径为4.42nm、标准差为0.98nm的球形银纳米颗粒,并研究了在不同反应时间后获得的银纳米颗粒对PVP和Alq3的荧光猝灭效应。通过深入研究发现,PVP的荧光猝灭效应主要由于其分子链上的酮基与Ag颗粒之间发生了静电吸附,进而导致处在激发态的PVP分子与银颗粒之间产生电子或者能量转移(即非辐射弛豫),猝灭了PVP的荧光发光;而Alq3的荧光猝灭效应则主要归因于银纳米颗粒的欧姆损耗。通过采用时域有限差分法进行模拟发现,溶液中随机分布的银纳米颗粒,不仅能够吸收激发电磁波,削弱激发场强度,而且能够吸收荧光分子辐射的电磁波,进而猝灭了Alq3分子的荧光效应。这些研究成果将有利于了解金属纳米颗粒与PVP及Alq3分子荧光发光之间的关系,为调控荧光发光提供指导。 相似文献
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V. V. Sapunov 《Journal of Applied Spectroscopy》2001,68(5):727-735
For solutions of the complexes of phthalocyanine (PhC) with magnesium (Mg-PhC) and of tetrachloromethyl-PhC with zinc (Zn-PhCCh) in mixtures of glycerin with dimethyl formamide (DMF) and for Zn-PhCCh in toluene and DMF it has been found that the electron absorption spectra substantially depend on the substance concentration. It is shown that these changes are attributable to the association of the molecules of pigments. The number of molecules in the associates and the equilibrium constants for this association are determined. The formation of the trimers of Mg-PhC in binary solutions and the dimers of Zn-PhCCh in toluene, DNF, and binary solutions has been established. It has been found that on association the Q absorption bands of the pigments shift to shorter wavelengths as compared to the bands of the monomers. For the Mg-PhC trimers, the shift is = 1410 cm–1, while for the Zn-PhCCh dimers it is 990 cm–1 in toluene, 930 cm–1 in DMF, and 925 cm–1 in the mixture of DMF with glycerin. It is concluded that the structure of the trimers and dimers is of the type of a stack in which molecules are arranged in parallel one above the other at a distance of 3.5 to 4.0 Å between the planes of the molecules. In association, the fluorescence intensity of the pigments decreases substantially (the decrease corresponds to the decrease in the concentration of the monomer molecules of phthalocyanines), with the fluorescence spectra remaining unchanged. Consequently, the associates of the pigments do not display pronounced fluorescence. 相似文献
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Halimah Mohamed. K ;Mahmoud Goodarz Naseri ;Amir Reza Sadrolhosseini ;Arash Dehzangi ;Ahmad Kamalianfar ;Elias B Saion ;Reza Zamiri ;Hossein Abastabar Ahangar ;Burhanuddin Y. Majlis 《中国物理快报》2014,(7):193-196
A laser ablation technique is applied for synthesis of silver nanoparticles in different concentrations of polyvinyl alcohol (PVA) aqueous solution. The ablation of high pure silver plate in the solution is carried out by a nanosecond Q-switched Nd:YAG pulsed laser. X-ray diffraction and transmission electron microscopy are implemented to explore the particles sizes. The effects of PYA concentrations on the absorbance of the silver nanoparticles are studied as well, by using a UV-vis spectrophotometer. The preparation process is carried out for deionized water as a reference sample. The comparison of the obtained results with the reference sample shows that the formation efficiency of nanoparticles in PYA is much higher and the sizes of particles are also smaller. 相似文献