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51.
Yoshihiro Kudo Ryo Fujihara Toshiaki Ohtake Shoichi Katsuta Yasuyuki Takeda 《Analytical sciences》2008,24(8):999-1003
The ion-pair formation constants {K(j)(0): j = MA (metal salt), MLA} of NaO(2)CCF(3) (Na(+)tfa(-)) and its ion-pair complexes (MLA) in water (w) were determined potentiometrically at 25 degrees C and an ionic strength (I) of zero. 15-Crown-5 (15C5), 18-crown-6 ethers (18C6), and their mono-benzo derivatives were used as crown ethers (L). The extraction of Natfa by these four L from w into 1,2-dichloroethane was done at 25 degrees C, and then the extraction constants (K(ex)) for NaLtfa were calculated by using the K(j) values, which were estimated from the corresponding K(j)(0) ones at I of the w-phases, and other equilibrium constants. Also, the distribution constants (K(D,MLA)) of NaLtfa between the two phases were obtained from a thermodynamic cycle expressing K(ex). An interaction of w-molecules with NaLA was considered using a relation of log K(D,MLA) with log K(D,L), derived from the Scatchard-Hildebrand equation, where K(D,L) denotes the distribution constant of L between the two phases. The interaction increased in the order of NaL (picrate) < free L = NaLMO(4) (M = Mn, Re) < NaLtfa for L = 15C5 and 18C6. 相似文献
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54.
Shinji?KoganezawaEmail author Yuta?Katsuta Renguo?Lu Hiroshi?Tani Norio?Tagawa 《Rheologica Acta》2017,56(5):477-486
Viscoelastic (VE) materials are widely used in daily life. For the effective utilization of VE materials, it is necessary to know their viscoelasticity with accuracy over a wide range of frequencies, especially for high frequencies. Currently, the viscoelasticity of solid-state materials is directly measured only in the low-frequency range; for high frequencies, it is estimated based on the time-temperature superposition (TTS) principle. However, it is generally recognized that the TTS principle is suitable only for estimating the viscoelasticity of rheologically simple materials for temperatures within a limited range that is higher than the glass-transition temperature. In this paper, we propose a device that can directly measure the shear modulus and tan δ values of solid-state VE materials at high frequencies. We also propose a method for compensating for the shear deformation mode resonance of VE materials based on the mass of the moving part, to gain a more accurate understanding of viscoelasticity in the high-frequency range, and discuss the causes of errors in the compensation method. Finally, we report the VE properties of natural rubber (NR 65 IRHD) measured using the developed device and compensation method, and compare the measured results with those obtained using commercial VE measurement equipment. 相似文献
55.
Yoshitomi Morizawa Hiroji Oda Koichiro Oshima Hitosi Nozaki 《Tetrahedron letters》1984,25(11):1163-1166
Addition of PhMe2SiMgMe, (PhMe2Si)2Zn, or PhMe2SiAlEt2 to allenes proceeds in the presence of various transition-metal catalysts. Whereas copper catalyzed silylmagnesation of 1,2-cyclononadiene gives 1-dimethyl-phenylsilyl-1-cyclononene exclusively, palladium catalyzed silylalumination affords 3-dimethylphenylsilyl-1-cyclononene preferentially with high degrees of regioselectivity. 相似文献
56.
Shoichi Katsuta Hayato Tachibana Yasuyuki Takeda 《Journal of solution chemistry》2001,30(12):1121-1124
Subject Index
Subject Index to Volume 30 相似文献57.
Hiroji Katsuta Rex B. McLellan Kazuo Furukawa 《Journal of Physics and Chemistry of Solids》1982,43(6):533-538
The permeability and diffusivity of hydrogen in molybdenum was measured by the time-lag method using molybdenum membranes prepared by electron beam melting and cleaned by argon ion etching. Measurements were also made on membranes prepared in this manner and subsequently coated with palladium. The inconsistencies in the previous data, a consequence of surface effects, have been clarified. The activation energy for H-diffusion in Mo is 10.6 KJ/mol. 相似文献
58.
Yasuyuki Takeda Kiyokazu End
Daisuke Yoshiyama Katsusige Watanabe Naoaki Fukada Shoichi Katsuta 《Journal of Molecular Liquids》2007,130(1-3):21-28
The constants of overall extraction equilibrium (Kex) and partition (KD,MLA) for various diluents and aqueous ion-pair formation (KMLA) of alkali metal (Li–Cs) picrate (MA) 1:1:1 complexes (MLA) with benzo-18-crown-6 (B18C6) and its open-ring analogue 1,2-bis[2-(2-methoxyethoxy)ethoxy]benzene (AC·B18C6) were determined at 25 °C, L being B18C6 or AC·B18C6; the distribution constants of AC·B18C6 were measured at 25 °C. The partition behavior of AC·B18C6 and the MLA complexes closely obeys regular solution theory, omitting chloroform; the molar volumes and the solubility parameters of AC·B18C6 and the MLA complexes were determined. The extraction selectivities of AC·B18C6 and B18C6 for the alkali metal picrates increase in the order Li < Na < Cs < K or Rb < or ≈ Rb or K and Li Na < Cs < Rb < K, respectively. The extraction selectivity of B18C6 for neighboring alkali metal ions in the periodic table is superior to that of AC·B18C6. The macrocyclic effect on the extraction-ability and -selectivity was quantitatively elucidated by the four fundamental equilibrium constants. 相似文献
59.
Dr. Naoya Oku Atsumi Hasada Kenji Kimura Dr. Hideharu Honoki Prof. Dr. Ryo Katsuta Prof. Dr. Arata Yajima Prof. Dr. Tomoo Nukada Prof. Dr. Ken Ishigami Prof. Dr. Yasuhiro Igarashi 《化学:亚洲杂志》2021,16(11):1493-1498
Ether lipids are a minor group of glycerolipids but widespread in nature, playing a vital function as membrane lipids, signalling molecules, or buoyant material. We have discovered sulfoquinovosylchimyl alcohol ( 1 ), a sulfonate-substituted glyceroglycolipid, from a lake ball-forming green alga Aegagropilopsis moravica (family Pithophoraceae), with the guidance of antimicrobial activity. The structure of 1 , including absolute configurations of all sterogenic centers, was established by extensive NMR analysis, chemical degradation studies, and finally by total synthesis. Lipid 1 is an ether variant of a lyso-form of sulfoquinovosyldiacylglycerol, a chloroplast-specific membrane lipid, and thus represents a new lipid class, sulfoquinovosylglyceryl ether. A high occurrence of mobile life form in the family Pithophoraceae and a unique behaviour of chloroplasts reported in closely related Aegagropila linnaei, the famous lake-ball alga, implies a possible role of lipid 1 or its acyl derivatives in ecological adaptation to dysphotic niches. 相似文献
60.
A reflection non-contact ultrasonic microscope system working both in amplitude and phase difference modes at 2 MHz has been developed using an air-coupled concave transducer made of piezoelectric polymer films of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)]. The transducer is composed of three 95 μm-thick P(VDF/TrFE) films stacked together, each of which is activated electrically in parallel by a driving source. The transducer has a wide aperture angle of 140° and a focal length of 10 mm. The measured two-way transducer insertion loss is 80 dB at 1.83 MHz. Despite 20 dB higher insertion loss than that estimated from Mason’s equivalent circuit, we have obtained clear amplitude acoustic images of a coin with transverse resolution of 150 μm, and clear phase difference acoustic images of the rough surface of a paper currency bill with depth resolution of sub-micrometer. Using two planar transducers of P(VDF/TrFE), we have also successfully measured in through-transmission mode the sound velocity and absorption of a 3 mm-thick silicone-rubber plate. The present study proves that, owing to its low acoustic impedance and flexibility, P(VDF/TrFE) piezoelectric film is very useful for high frequency acoustic imaging in air in the MHz range. 相似文献