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21.
In order to confirm the existence of regions I and II in aqueous solutions of butoxyethanol(BE), the concentration and temperature
dependences of enthalpies of mixing of aqueous BE solutions with some organic solvents were measured. It has been found that
the increments of apparent enthalpies of mixing per mole of water with respect to the mole fraction of BE change irregularly
at a certain concentration. This concentration nearly corresponds to the reported boundary between regions I and II. Although
similar behavior has also been observed in aqueous solutions of iso-butoxyethanol, aqueous solutions oftert-butoxyethanol have shown no anomalous behaviors.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
22.
Hiromichi Fujioka 《Tetrahedron letters》2010,51(15):1945-2017
The first asymmetric total syntheses of the (+)- and (−)-cryptocaryones are described. Removal of the acetal unit of the enone acetal 5, which was obtained in our previous study from the cyclohexadiene acetal 3, afforded the enone acetal 8 in a one-pot procedure. The acylation of 8 with cinnamoyl chloride and subsequent hydrolysis of the resulting acetal gave the lactol 11. Its oxidation with NIS and tetra-n-butylammonium iodide (TBAI) finally furnished the natural (+)-cryptocaryone 2. The same procedure from ent-3 afforded the unnatural one 1. 相似文献
23.
Fujioka H Nakahara K Hirose H Hirano K Oki T Kita Y 《Chemical communications (Cambridge, England)》2011,47(3):1060-1062
A novel and rapid approach to chiral mono- or di-substituted spiroketals based on remote asymmetric induction by intramolecular iodoetherification of ene or diene ketals has been developed. This strategy concisely offers 5,5- and 5,6-spiroketals including the natural insect pheromone of the wasp. 相似文献
24.
A specific, sensitive and accurate quantitative analysis of testosterone propionate in human plasma was developed using gas chromatography-mass spectrometry-selected-ion monitoring. For the calculation of testosterone propionate in plasma, peak height ratios were measured by selected-ion monitoring performed on the molecular ions of the trifluoroacetyl derivative of testosterone propionate (m/z 440) and testosterone propionate-19,19,19-d3 (m/z 443). The sensitivity of the method was judged from the lower limit of the detection of the mass spectrometer which was at 20 pg. The inter-assay coefficients of variation and relative error at a concentration of 1.31 ng/ml of plasma were 5.47% and -2.3%, respectively. The method described was applied to the determination of plasma concentrations of testosterone propionate-19,19,19-d3 following an intramuscular dose of testosterone propionate-19,19,19-d3 in a healthy male volunteer. 相似文献
25.
T. Shinohara K. Sasaki H. Onodera M. Fujioka I. Kawasuji H. Watanabe 《Physics letters. A》1978,66(5):410-412
The charge densities of the 4s electrons in Fe2+ and Fe3+ ions in the ionic compound, NiO, were measured from an internal conversion experiment and compared with some predicted values on the basis of different theoretical methods. 相似文献
26.
Brownian dynamics simulations of shear flows are carried out for various suspensions of ellipsoids interacting via the Gay-Berne
potential. In this simulation all the systems of the suspension are in a liquid crystalline phase at rest. In a shear flow
they exhibit various motions of the director depending on the shear rate: the continuous rotation, the intermittent rotation,
the wagging-like oscillation, and the aligning. The director is almost always out of the vorticity plane when it rotates,
that is the kayaking. The number density of the system and the inter-particle potential intensity significantly affect the
shear rate dependence of orientation. In particular, the continuous rotation of director is maintained to higher shear rates
for the system with a stronger potential. Furthermore, the rheological properties are examined. The shear-thinning in viscosity
is observed, but the negative first normal difference is not obtained. 相似文献
27.
Y. Kamii I. Waki H. Fujioka M. Oshima H. Miki M. Okuyama 《Applied Surface Science》2002,190(1-4):348-351
Electrical characteristics of Mg-doped p-GaN activated with Ni catalytic layers have been investigated by means of temperature-dependent Hall effect measurements. It has been revealed that the Ni layer on GaN enhances activation of the acceptor in the whole annealing temperature range. This enhancement is remarkable especially at temperatures below 500 °C and can be attributed to the catalytic effect for the hydrogen desorption. We have found that the donor concentrations in the samples activated with the Ni catalysts are also higher than those activated without Ni. This is probably due to the catalytic effect of Ni for the nitrogen desorption. In addition, it has been found that the ionization energies of the Mg acceptors in GaN activated with the Ni layer are decreased from 170 to 118 meV as the acceptor concentration increases. 相似文献
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