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991.
The adsorption and micellar behavior of diethylene glycol mono-n-tetradecyl ether (C14E2), sodium 3,6,9,12-tetraoxaoctacosanoate (TOOCNa), and their mixture at a 1:1 molar ratio have been studied by film balance, Brewster angle microscopy (BAM), and surface tensiometry at different temperatures. The monolayers of pure C14E2 and its mixture with TOOCNa show a first-order phase transition with a conspicuous cusp point in their respective adsorption isotherms. This is further confirmed by the observation of bright two-dimensional condensed phase domains visualized by BAM just after the appearance of the phase transition. It is interesting to note here that for C14E2, condensed domains are observed up to 19 degrees C, while in the mixed system, they are observed up to 22 degrees C. To understand why in the mixed system the domains are observed at higher temperatures than for pure C14E2, we have measured the temperature dependency of the equilibrium surface tension at > or = cmc (gammacmc) values of both the pure and the mixed systems. The gammacmc values of pure C14E2 remain almost constant, while those of pure TOOCNa and its mixture with C14E2 decrease appreciably with increasing temperature. It is concluded that higher degree of dehydration of the ethylene oxide (EO) chain reduces the head-group size of TOOCNa, which outweighs the combined effect of the repulsive interactions between the head-groups and the thermal motion of the adsorbed molecules. Furthermore, C14E2 being inserted into the TOOCNa monolayer reduces the electrostatic repulsions between the charged heads, and consequently, the adsorbed monolayers attain closer molecular packing. As a result, the gammacmc values of both pure TOOCNa and its mixture with C14E2 decrease with increasing temperature. This facilitates the formation of condensed domains in the mixed system at higher temperatures, whereas none of the individual members can show any indicative feature of phase transition under the same experimental conditions. 相似文献
992.
The determination of psilocybin was carried out by reversed-phase liquid chromatography (HPLC) with fluorescence (FL) detection. Psilocybin was labeled with 5-dimethylaminonaphthalene-1-[N-(2-aminoethyl)]sulfonamide (DNS-ED) at 60 °C for 4 h in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the activation reagent. The resulting derivative was separated on a Mightysil RP-18 GP column (150 mm × 4.6 mm, i.d. 3 μm) with the mixture of 50 mM ammonium acetate (AcONH4) and CH3CN, and detected at 539 nm (excitation at 321 nm). The structure of the derivative was identified by HPLC-ESI-MS. A good linear relation of the calibration curve of psilocybin was observed under the proposed conditions for labeling, separation and detection. The quantification limit was 4.4 ng in 1 mg dried mushroom. The proposed procedure was successfully used for the determination of psilocybin in real samples. The contents of psilocybin in six magic mushrooms by the proposed HPLC-FL method were less than 20.0 ng in 1 mg dried samples. 相似文献
993.
Biodegradation of bisphenol a by fungi 总被引:1,自引:0,他引:1
Chai W Handa Y Suzuki M Saito M Kato N Horiuchi CA 《Applied biochemistry and biotechnology》2005,120(3):175-182
The biologic degradation of 2,2-bis(4-hydroxyphenyl)propane (bisphenol A [BPA]; 1) was studied with 26 fungi. An initial BPA concentration of 40 ppm in an aqueous solution was degraded in the dark for 14 d. Among the 26 strains tested, 11 degraded BPA at 50% or more. Furthermore, four strains (F. sporotrichioides NFRI-1012, F. moniliforme 2-2, A. terreus MT-13, and E. nidulans MT-98) were more effective for degradation of BPA. 相似文献
994.
Mukai T Yoshio M Kato T Yoshizawa M Ohno H 《Chemical communications (Cambridge, England)》2005,(10):1333-1335
Two types of thermotropic smectic phase and of anisotropic ion conduction were observed in an amphiphilic ionic liquid, N-ethyl-N'-dodecylimidazolium dodecyl sulfonate/lithium tetrafluoroborate mixture. 相似文献
995.
A novel neutral trinuclear Cu(II) complex of a Schiff base ligand derived from D-glucose has been synthesised and structurally characterised, which exhibits excellent alcohol binding affinity and activates the C-Cl bond of chloroform in the presence of primary amine. 相似文献
996.
Poggio M Steeves GM Myers RC Kato Y Gossard AC Awschalom DD 《Physical review letters》2003,91(20):207602
The shaping of nuclear spin polarization profiles and the induction of nuclear resonances are demonstrated within a parabolic quantum well using an externally applied gate voltage. Voltage control of the electron and hole wave functions results in nanometer-scale sheets of polarized nuclei positioned along the growth direction of the well. Applying rf voltages across the gates induces resonant spin transitions of selected isotopes. This depolarizing effect depends strongly on the separation of electrons and holes, suggesting that a highly localized mechanism accounts for the observed behavior. 相似文献
997.
A systematic characterization of a series of La@C n by temperature-dependent electron spin resonance (ESR) in solution was performed. The anisotropic ESR parameters of theg-factor, the hyperfine coupling tensor, and nuclear quadrupole interaction were determined by a quantitative analysis of the linewidth on the basis of the hydrodynamics in solution. As a result, it was found that the electronic structure of all La@C n was stabilized by an intramolecular charge transfer and can be described as La3+@C n 3? . An interesting feature of the spin dynamics beyond the hydrodynamics in solution was deduced for La@C80-I and La@C84-II. 相似文献
998.
High-resolution electron microscopy of individual metallofullerene molecules on the dipole orientations in peapods 总被引:1,自引:0,他引:1
K. Suenaga T. Okazaki K. Hirahara S. Bandow H. Kato A. Taninaka H. Shinohara S. Iijima 《Applied Physics A: Materials Science & Processing》2003,76(4):445-447
Electron microscopy with atomic sensitivity enables us to obtain a direct image of the intra-molecular structure of metallofullerenes
encapsulated inside single-walled carbon nanotubes. By a comparison of high-resolution images with a simulation to extract
the relative atom positions for encaged metal atoms in each molecule, the distribution of the molecular orientations and interactions
between adjacent molecules in metallofullerene peapods have been statistically analyzed. The results are suggestive of strong
interactions between fullerene–fullerene and fullerene–tube in peapods at room temperature.
Received: 10 October 2002 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +81-298/61-6310, E-mail: suenaga-kazu@aist.go.jp 相似文献
999.
An algorithm for implementing the approximation of the leading irreducible representation of the SU(3) group is expounded for a microscopic Hamiltonian involving the potential energy of nucleon-nucleon interaction. An effective Hamiltonian is constructed that reproduces the results of calculations with nucleon-nucleon potentials used in the theory of light nuclei. It is shown that, in many respects, the structure of the effective Hamiltonian is similar to the structure of the Hamiltonian of a triaxial rotor and that, for the wave functions in the Elliott scheme, one can go over to a space where linear combinations of Wigner D functions appear to be the transforms of these functions, but where their normalization requires dedicated calculations. 相似文献
1000.
Kobayashi K Ohtsu H Wada T Kato T Tanaka K 《Journal of the American Chemical Society》2003,125(22):6729-6739
The ruthenium oxyl radical complex, [Ru(II)(trpy)(Bu(2)SQ)O(.-)] (trpy = 2,2':6',2"-terpyridine, Bu(2)SQ = 3,5-di-tert-butyl-1,2-benzosemiquinone) was prepared for the first time by the double deprotonation of the aqua ligand of [Ru(III)(trpy)(Bu(2)SQ)(OH(2))](ClO(4))(2). [Ru(III)(trpy)(Bu(2)SQ)(OH(2))](ClO(4))(2) is reversibly converted to [Ru(III)(trpy)(Bu(2)SQ)(OH-)](+) upon dissociation of the aqua proton (pK(a) 5.5). Deprotonation of the hydroxo proton gave rise to intramolecular electron transfer from the resultant O(2-) to Ru-dioxolene. The resultant [Ru(II)(trpy)(Bu(2)SQ)O(.-)] showed antiferromagnetic behavior with a Ru(II)-semiquinone moiety and oxyl radical, the latter of which was characterized by a spin trapping technique. The most characteristic structural feature of [Ru(II)(trpy)(Bu(2)SQ)O(.-)] is a long Ru-O bond length (2.042(6) A) as the first terminal metal-O bond with a single bond length. To elucidate the substituent effect of a quinone ligand, [Ru(III)(trpy)(4ClSQ)(OH(2))](ClO(4))(2) (4ClSQ = 4-chloro-1,2-benzosemiquinone) was prepared and we compared the deprotonation behavior of the aqua ligand with that of [Ru(III)(trpy)(Bu(2)SQ)(OH(2))](ClO(4))(2). Deprotonation of the aqua ligand of [Ru(III)(trpy)(4ClSQ)(OH(2))](ClO(4))(2) induced intramolecular electron transfer from OH- to the [Ru(III)(4ClSQ)] moiety affording [Ru(II)(trpy)(4ClSQ)(OH.)]+, which then probably changed to [Ru(II)(trpy)(4ClSQ)O(.-)]. The antiferromagnetic interactions (J values) between Ru(II)-semiquinone and the oxyl radical for [Ru(II)(trpy)(Bu(2)SQ)O(.-)] and for [Ru(II)(trpy)(4ClSQ)O(.-)] were 2J = -0.67 cm(-1) and -1.97 cm(-1), respectively. 相似文献