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排序方式: 共有297条查询结果,搜索用时 31 毫秒
71.
Chutiparn Lertvachirapaiboon Itaru Kiyokawa Kazunari Shinbo Keizo Kato 《Analytical letters》2019,52(12):1939-1950
Silver nanoprisms (AgNPrs) have unique optical phenomena due to their localized surface plasmon resonance that results in the extinction of light from the visible to the near-infrared spectral region. In this study, we propose the colorimetric determination of silver nanoprisms in microchannels using a smartphone camera. Image acquisition was performed by capturing an image of the colloidal solution of the silver nanoprisms in the microchannel using the transmitted light. Red, green, and blue chromaticity levels were extracted from the recorded images for further quantification of the silver nanoprisms. This technique was employed for the detection and colorimetric determination of hydrogen peroxide (H2O2). Good linearity between the change in the green chromaticity level and concentration of hydrogen peroxide was observed for values from 10 to 300?μM with an R2 value of 0.9670. We anticipate that the developed methodology for the quantification of silver nanoprisms and hydrogen peroxide by monitoring the change in color in the images of transmitted light will enhance the development of simple, rapid, and reliable detection systems for quality control in the production of silver nanoprisms as well as in chemical sensor applications. 相似文献
72.
Shuntaro Mataka Kazufumi Takahashi Masashi Tashiro Wei-Hua Lin Shin-Ichi Iwasaki Tetsuo Tsutsui Shogo Saito Shinji Akiyama Tadashi Yonemitsu 《Journal of heterocyclic chemistry》1989,26(1):215-219
Reversible color change of 4,6,7-tri(alkoxy-substituted phenyl)-1,2,5-thiadiazolo[3,4-c]pyridines 5 in the solid state was observed: on grinding, yellow crystals of 5 became an orange amorphous solid which, on heating or washing with an appropriate solvent, gave the original yellow crystals. 相似文献
73.
Makoto Ohki Haruo Sakurai Shogo Kozaki 《International Journal of Infrared and Millimeter Waves》1997,18(10):2031-2045
This paper is described for T-matrix analysis of the electromagnetic wave diffraction from a Fourier grating that the boundary
value problem is treated by applying the extended boundary condition. The rigorous form of the expression of matrix elements
is presented in the term of Bessel functions of the first kind. The error of power conservation versus the truncated number
has been examined for mode number. Diffraction efficiencies versus groove depth and wavelength for a second or third harmonic
wave of Fourier grating have been discussed. Numerical results are in good agreement with those obtained from other method
and experimental values. Reasonable numerical results are presented for a groove depth per period of the Fourier grating less
than 0.25. 相似文献
74.
Masahiro Hayashi Shogo Tawada Yoshihiro Kubota Yoshihiro Sugi Jong Ho Kim 《Reaction Kinetics and Catalysis Letters》2004,83(2):329-335
Although extensive isomerization of 4,4'-diisopropylbiphenyl (4,4'-DIPB) occurred at 300oC over H-mordenite, high selectivity for 4,4'-DIPB among DIPB isomers was observed over silica-modified H-mordenite. This
is due to the prevention of the isomerization of 4,4'-DIPB by the deactivation of external acid sites.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
75.
N-Isobutylidenemethylamine reacted with dimethyl methoxymethylenemalonate to afford the N-alkylation product 3a exclusively. Exchanging the N-substituent of the Schiff's base from methyl to t-butyl altered the course of the reaction, allowing Michael addition to take place predominantly. The Michael adduct 4c on reaction with hydrazinoalkanols 6a,b, 6c,d and 6e gave tetrahydropyrazolo[5,1-b]oxazoles 9a,b , tetrahydro-pyrazolo[5,1-b][1,3]oxazines 9c,d and hexahydropyrazolo[5,1-b][1,3]oxazepine 9e , respectively. 相似文献
76.
A convenient and environmentally-friendly synthetic method of olefins via deacylation reaction is described. The reaction gives olefins by condensation of aldehydes with a variety of 1,3-dicarbonyl compounds in the presence of anhydrous potassium carbonate at room temperature in high yields (70-90%) in one step. The synthetic potential of this strategy can be used as an alternative procedure to the Wittig, Wittig-Horner reactions. The stereochemistry of the resulted olefins was determined by NOE experiment with correct radio frequency and X-ray analysis. The E/Z selectivity of the deacylation reaction depends on the α-substituents of the 1,3-dicarbonyl compounds. 相似文献
77.
Haruyuki Okamura Shogo Toda Masahiro Tsunooka Masamitsu Shirai 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):3055-3062
Photocrosslinkable systems with thermally cleavable properties based on blends of poly(vinyl phenol) (PVP) and diepoxides were investigated. Thermally cleavable diepoxides as crosslinkers were prepared and characterized. As a thermally cleavable linkage, a tertiary ester moiety was incorporated into the crosslinker molecule. PVP/crosslinker blended films containing photoacid generators (PAGs) became insoluble in solvents after UV irradiation and subsequent post‐exposure‐bake (PEB) treatment. With a rise in the PEB temperature, the insoluble fraction of the irradiated films increased, passed through a maximum value, decreased, and increased again at elevated baking temperatures. The insolubilization profiles of the irradiated films were complicated and strongly dependent on the type of PAG used, the structure of the crosslinkers, and the PVP/crosslinker ratio. A mechanism for the thermal degradation was studied with Fourier transform infrared spectroscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3055–3062, 2002 相似文献
78.
It was found that a degree of the binding of alkylphenols to N-alkylacrylamide gel increased transitionally to induce the volume phase transition of gel. Binding isotherms of nonylphenol (n-Ph), propylphenol (p-Ph), ethylphenol (e-Ph), methylphenol (m-Ph), and phenol (Ph) to N-isopropylacrylamide (NIPA), N,N-diethylacrylamide (DEA), N,N-dimethylacrylamide (DMA), and acrylamide (AM) gels were examined. Two types of binding, the site binding at beta < 1 and the multimolecular binding at beta > 1, were observed, where beta was a degree of binding to a monomeric unit of the chain. The former binding was analyzed with the Hill equation applicable to the cooperative binding and the latter binding with the Brunauer-Emmett-Teller (BET) equation applicable to the multilayer adsorption. The binding constant, K, and the Hill coefficient, N, decreased and increased, respectively, in the order of DEA, NIPA, and DMA gels in the case where the binding alkylphenol was the same. The K value increased in the order of Ph, m-Ph, e-Ph, p-Ph, and n-Ph that bound to the same type of gel. The N value was found to change little with the type of binding alkylphenol. The complexes of N-alkylamide with alkylphenol were condensed to form the ordered nanostructures that were observed as broad scattering peaks in small-angle X-ray scattering experiments. The fluorescence excimer emission was observed for the phenol-binding DMA gel, which corresponded to the condensed state of phenol. 相似文献
79.