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81.
Hiromichi Sagitani Yoshie Hayashi Michio Ochiai 《Journal of the American Oil Chemists' Society》1989,66(1):146-152
The synthesis and solution properties of a homologous series of polyglycerol dodecyl ethers (R12Gn) are described. The phase behavior, surface tension, cloud point and HLB value (hydrophile lipophile balance) of these surfactants
in aqueous solutions and in mixed solutions of water/oil have been investigated and compared with values for polyoxyethylene
dodecyl ether (R12EOn). The surface tension measurements showed that R12Gn have sufficiently low values of surface tension and critical micellization concentration (cmc) to serve as useful nonionic
surfactants. The mesophases appearing in the R12Gn systems were more stable in a high temperature range than the mesophases of the R12EOn systems. The cloud point and HLB data indicated that addition of one glycerol group was equivalent to the addition of three
oxyethylene units, as far as the hydrophilic property was concerned. The phase diagrams of the R12Gn/dodecane/water systems showed that the solubilizing and emulsifying powers of R12Gn were greater than those of R12EOn. It is concluded that the polyglycerol chain can be even more useful as the hydrophilic part of nonionic surfactants than
the conventional oxyethylene chain. 相似文献
82.
The synthesis/hydrolysis of wax esters was studied in an aqueous solution using purified rat pancreatic lipase, porcine pancreatic
carboxylester lipase, and Pseudomonas fluorescens lipase. The equilibrium between wax ester synthesis and hydrolysis favored ester formation at neutral pH. The synthesizing
activities were measured using free fatty acid or triacylglycerol as the acyl donor and an equimolar amount of long-chain
alcohol as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with these lipases,
was ester was synthesized, in a dose- and time-dependent manner, and the apparent equilibrium ratio of palmityl oleate/free
oleic acid was about 0.9/0.1. These lipases catalyzed the hydrolysis of palmityl oleate emulsified with gum arabic, and the
apparent equilibrium ratio of palmityl oleate/free oleic acid was also about 0.9/0.1. The apparent equilibrium ratio of wax
ester/free fatty acid catalyzed by lipase depended on incubation pH and fatty alcohol chain length. When equimolar amounts
of trioleoylglycerol and fatty acyl alcohol were incubated with pancreatic lipase, carboxylester lipase, or P. fluorescens lipase, wax esters were synthesized dose-dependently. These results suggest that lipases can catalyze the synthesis of wax
esters from free fatty acids or through degradation of triacylglycerol in an aqueous medium. 相似文献
83.
Hiromichi Shimada Nobuyuki Matsubayashi Toshio Sato Yuji Yoshimura Motoyasu Imamura Takashi Kameoka Akio Nishijima 《Catalysis Letters》1993,20(1-2):81-86
The dispersion of molybdenum sulfide catalysts was characterized based on the lateral dimensions of MoS2 crystallites estimated by EXAFS. A new index ofN(Mo)/N(S), instead ofN(Mo), was used to estimate the average MoS2 size to minimize the contribution of the coexisting oxide or oxisulfide phase in the catalysts. EXAFS showed some advantages over other techniques, such as TEM or XPS. 相似文献
84.
Hiromichi Shimada Nobuyuki Matsubayashi Motoyasu Imamura Toshio Sato Akio Nishijima 《Catalysis Letters》1996,39(1-2):125-128
Non-destructive depth profiling analysis with high surface sensitivity was performed by XPS with synchrotron radiation excitation. Comparison of the measured atomic ratios with the simulated ones revealed the presence of a thin Al- and Na-rich overlayer at the external surface of NaY particles. For HY zeolite particles, a gradual decrease in the Al/Si ratio from the external surface to the bulk was observed. 相似文献
85.
Masafumi Takesue Kenji Shimoyama Sachiko Murakami Yukiya Hakuta Hiromichi Hayashi Richard L. Smith Jr. 《The Journal of Supercritical Fluids》2007,43(2):214
Phase formation of Mn-doped zinc silicate (Zn2SiO4:Mn2+, ZSM) in high-temperature and high-pressure water was studied by in situ observations with a hydrothermal diamond anvil cell (HDAC). Precursor was prepared with zinc oxalate dihydrate, manganese oxalate, and silica, where the Zn/Mn/Si molar ratio was 192/8/120 to 199/1/120. Conditions of particle formation were at temperatures up to 650 °C and at pressures up to 1250 MPa. Precursors dissolved at temperatures of 145–203 °C and needle-like particles formed through homogeneous nucleation at temperatures from 357 to 374 °C, close to the critical point of water. The needle-like particles grew at growth rates of 0.5–3.8 μm/s and were identified to be ZSM as evident from their green luminescence. ZSM synthesized in supercritical water (400 °C for 180 min) by batch reactions had comparable luminescence with that of ZSM produced by solid-state reaction (1200 °C for 240 min) using the same precursor. The key finding in this work is that the precursors can be made to dissolve in near-critical water and that this allows ZSM to form via a homogeneous nucleation process. 相似文献
86.
87.
Muhammad AGUNG Shinfuku NOMURA Shinobu MUKASA Hiromichi TOYOTA Otsuka KAZUHIKO Hidekazu GOTO 《等离子体科学和技术》2017,19(5)
The objectives of this research were to understand the process of converting toluene into phenol in a one-step process directly from a water–toluene mixture using the plasma in-liquid method.Experiments were conducted using 27.12 MHz radio frequency(RF) in-liquid plasma to decompose a solution of 30% toluene. Based on the experimental results as evaluated using gas chromatography–mass spectrometry(GC–MS), along with additional analysis by the Gaussian calculation, density functional theory(DFT) hybrid exchange–correlational functional(B3LYP)and 6-311 G basis, the phenol generated from toluene was quantified including any by-products.In the experiment, it was found that OH radicals from water molecules produced using RF inliquid plasma play a significant role in the chemical reaction with toluene. The experimental results suggest that phenol can be directly produced from a water–toluene mixture. The maximum phenol yields were 0.0013% and 0.0038% for irradiation times of 30s and 60s,respectively, at 120 W. 相似文献
88.
Teruyasu Mizoguchi Hiromichi Ohta Hak‐Sung Lee Nobuaki Takahashi Yuichi Ikuhara 《Advanced functional materials》2011,21(12):2258-2263
By combining state‐of‐the‐art microscopy, spectrosccopy, and first‐principles calculations, atomic‐scale intermixing behavior at heterointerfaces in SrTiO3‐based superlattices is investigated. It is found that Nb is confined to a unit‐cell thickness without intermixing, whereas Ba diffuses only to the adjoining Nb‐doped SrTiO3 layer. It is revealed that the intermixing behaviors at the heterointerfaces are determined by not only the migration energy, but also by the vacancy‐formation energy and the Fermi energy of each layer. Based on these results, we find a method to control the atomic‐scale intermixing at the nonpolar heterointerfaces and clearly demonstrate the property improvements obtained by constructing an abrupt heterointerface. 相似文献
89.
Drying of sintered spheres of coarse glass beads with a wide sintering range in superheated steam under vacuum was studied. In samples with sintered angles of 7.5° –27°, the experimental normalized drying rates in superheated steam at pressures of 7.3-7.9mmHg were smaller than those for 56.0-767.6 mmHg in the vicinity of the critical moisture cotents for 56.0-767.6GmmHg. As reported in an earlier paper, there were 相似文献
90.
The application of thermal microscopes to the measurement of local thermal properties has drawn considerable scientific interest. We report on the application of a thermal microscope to the measurement of thermal effusivity for films comprising alumina deposited on a substrate, which were fabricated by an electrophoretic deposition method. The measured data was analyzed to consider the undulations on the sample surface The thermal effusivity of these samples was approximately 1×103 Js?0.5m?2K?1; this value is smaller than that for dense alumina because the alumina grain makes contact with a point. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20227 相似文献