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61.
A. Kasgöz K. Yoshimura T. Misono Y. Abe 《Journal of Sol-Gel Science and Technology》1994,1(2):185-191
The preparation of SiO2-TiO2 thin films by the sol-gel method using silicic acid and titanium tetrachloride as starting materials was studied. The homogeneous sols were obtained by the condensation reaction of silicic acid with titanium tetrachloride in methanol-tetrahydrofuran. The dipcoating of slide glasses and silicon wafers followed by heat treatment gave oxide thin films of 88–93% transmittance, 3000–4500 Å thickness, and 1.45–1.80 refractive index, depending on heat-treatment temperature and TiO2 content. FT-IR measurement showed that the Si-O-Ti bond is formed even in the sol and films. The variations of film thickness and refractive index on transformation from the gels into the oxides were found to be quite low. 相似文献
62.
Hashizaki K Taguchi H Itoh C Sakai H Abe M Saito Y Ogawa N 《Chemical & pharmaceutical bulletin》2005,53(1):27-31
Poly(ethylene glycol)-grafted liposomes (PEG-liposomes) were prepared from dipalmitoylphosphatidylcholine (DPPC) with various amounts of distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (DSPE-PEG) with PEG molecular weights of 1000, 2000, 3000 and 5000. The effects of DSPE-PEG concentration on the permeability of PEG-liposomes were investigated using carboxyfluorescein (CF). In the gel state, the CF leakage from PEG-liposomes was decreased with increasing mole fractions of DSPE-PEG for all PEG molecular weights. In the liquid-crystalline state, the CF leakage from PEG-liposomes containing DSPE-PEG1000 gradually increased with increasing mole fractions of DSPE-PEG, while that of PEG-liposomes whose molecular weight in PEG units was above 2000 rapidly decreased by the addition of DSPE-PEG. Furthermore, no effect of PEG molecular weight on CF leakage was observed. The relationship between the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) (or 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH)) and the mole fraction of DSPE-PEG for PEG-liposomes was also investigated. No significant changes in fluorescence polarization of DPH for liposomal bilayer membranes was observed in the gel and liquid-crystalline states due to the addition of DSPE-PEG, while that of TMA-DPH was decreased compared with that of liposomes without DSPE-PEG in both states. 相似文献
63.
Imabayashi S Mita T Kakiuchi T 《Langmuir : the ACS journal of surfaces and colloids》2005,21(6):2474-2479
The effect of charge-inverting modification of single surface lysine residue on the electron transfer (ET) reaction of horse heart cytochrome c (cyt c) is examined for 12 different types of mono-4-chloro-2,5-dinitrobenzoic acid substituted cyt c (mCDNPc) adsorbed on a Au(111) electrode modified with a self-assembled monolayer (SAM) of 7-mercapto-heptanoic acid (MHA). A negative shift in the redox potential by 10-35 mV as compared to that of native cyt c and a monolayer coverage in the range of 13-17 pmol cm(-2) are observed for electroactive mCDNPc's. The magnitude of the decrease in the ET rate constant (k(et)) of mCDNPc's compared with that of native cyt c depends on the position of the CDNP substitution. For mCDNPc's in which the modified lysine residue is outside of the interaction domain of cyt c with the SAM, the ratio of the k(et) of mCDNPc to that of native cyt c is correlated to the change in the dipole moment vector of cyt c due to the CDNP modification. This correlation suggests that the dipole moment of cyt c determines its orientation of adsorption on the SAM of MHA and significantly affects the rate of the ET. The CDNP modification of lysine residues at the interaction domain significantly decreases the rate, demonstrating the importance of the local charge environment in determining the rate of ET. 相似文献
64.
The dispersive component
s
d
of the surface free energy of glass fibers and its interaction energy with alkanes, benzene, 1-nitropropane, ethyleneglycol, glycerol, formamide, and water were quantitatively determined by the tensiometric method within two liquids. The values of nondispersive interaction energy I
SL
p
were found to be a linear function of the square root of the nondispersive component of the surface free energy of liquids. This suggests that the nondispersive interaction energy may be represented by the geometric mean of the nondispersive component of the surface free energy of a solid and a liquid. The slope gave the nondispersive component
s
p
of the surface free energy. The
s
p
values are 33 and 14 mJ/m2 for the untreated and aminosilane-treated fibers, respectively, suggesting that organophilic character has developed on the surface after aminosilane treatment. The
s
p
value was almost similar after the treatment, probably because of the polar characteristics of amino groups. 相似文献
65.
Paterno-Buchi coupling, photochemical [2 + 2] cycloaddition, of carbonyl compounds 2a-f with 2-siloxyfurans 1a-d has been investigated in detail. The stereoselective formations of exo-oxetanes 3 and 4 were observed in high yields. The regioselectivity (double-bond selection, 3 vs 4) was found to be largely dependent upon the carbonyls, the substituents at the furan ring, and the excited state of the carbonyls (singlet vs triplet). The photoreaction of aldehydes 2a-c gave bicyclic exo-oxetanes 3 and 4 at regio-random, independent upon their excited states and the substituents at furan ring. However, the photoreaction of the triplet state of ketones 2d-f was found to give regioselectively exo-oxetanes 4, except for the 4-methyl-2-siloxyfurane 1d case. The singlet-excited state of acetone 2f gave both oxetanes 3 and 4 at regio-random. For the singlet-state photochemistry, the approach direction of the electrophilic oxygen of the excited carbonyls to the furan ring is proposed to be an important factor for the exo-stereoselection. The Griesbeck model can rationalize the regio- and exo-selective formation of oxetanes in the triplet-state photoreaction. 相似文献
66.
Yusuke Kaminaga Takahiro Yamada Hisanori Yamane 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):i57-i58
A new quaternary oxide, calcium yttrium stannate, Ca0.8Y2.4Sn0.8O6, is isostructural with Mg3TeO6 (trigonal, R). The empirical formula can be expressed as (Ca0.2667Y0.7333)6(Y0.4Sn0.6)SnO12. The Ca/Y site has a distorted coordination octahedron of O atoms, with Ca/Y—O distances ranging from 2.227 (3) to 2.350 (3) Å, while the octahedra of O atoms that coordinate to the Sn and Y/Sn sites are nearly regular, with an Sn—O distance of 2.066 (2) Å and a Y/Sn—O distance of 2.147 (3) Å. 相似文献
67.
68.
Tomihiro Nishiyama Takahiro Nishikawa Fukiko Yamada 《Journal of heterocyclic chemistry》1989,26(6):1687-1690
The stereochemical properties of two 2-methyl-3-phenyl-1,3-oxazolidines and two of its 5-methyl substituted and four of its 2,5-dimethyl substituted derivatives have been investigated by pmr and cmr methods. The compounds of 2,5-dimethyl-3-phenyl-1,3-oxazolidines exist in isomeric cis and trans forms at the two methyl groups on the heterocyclic ring. 相似文献
69.
Three acyclic polythioethers containing 2-thienyl units at both ends were synthesized and the effect of substituent on the extraction of copper(II) was studied. The methyl groups in the terminal thiophene ring have imparted an appreciable degree of increase in the percent extraction of copper(II), while the introduction of chlorine atoms into the 2-thienyl unit resulted in the reverse effect. Among the counter dye anions examined, tetrabromophenolphthalein ethylester was the best one for copper(II) extraction. The composition of extracted species was evaluated to be 122 (Cu(II)/polythioether/dye anion). Quantitative extraction of copper(I) was attained as complexes with various triphenylmethane dyes, i.e., bromocresol green, bromothymol blue, bromo-phenol blue and pyrogallol red. Copper(I) in organic phase was completely back-extracted with 2 mole/l sulfuric acid containing 10% hydrogen peroxide. 相似文献
70.
Abe K Akagi T Anthony PL Antonov R Arnold RG Averett T Band HR Bauer JM Borel H Bosted PE Breton V Button-Shafer J Chen JP Chupp TE Clendenin J Comptour C Coulter KP Court G Crabb D Daoudi M Day D Dietrich FS Dunne J Dutz H Erbacher R Fellbaum J Feltham A Fonvieille H Frlez E Garvey D Gearhart R Gomez J Grenier P Griffioen KA Hoibraten S Hughes EW Hyde-Wright C Johnson JR Kawall D Klein A Kuhn SE Kuriki M Lindgren R Liu TJ Lombard-Nelsen RM Marroncle J Maruyama T Maruyama XK McCarthy J Meyer W 《Physical review letters》1995,74(3):346-350