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61.
CROWNPAK CR(+) column, which is powerful for the separation of amino acid enantiomers, must be used at a column temperature below 50°C and a mobile phase containing less than 15% methanol, because the chiral crown ether moiety of the stationary phase is dynamically coated on an ODS matrix. The second peak of the enantiomers of alanine-β-naphthylamide (Ala-β-NA) appeared at 204 min (k2=148) by using ordinary mobile phase, that is, a mixture of 10 mM perchloric acid and 15% methanol. In this study, enantiomer separations of Ala-β-NA and 1-(1-naphthyl)ethylamine (1-NEA), both of which are hydrophobic amino compounds, were investigated through the modification of the mobile phase. Addition of crown ether, cyclodextrins (CDs), cations, etc., affected the stability of the complex between an analyte and the chiral moiety, leading to fast separation. The second peak of the enantiomers of Ala-β-NA appeared at 68 min (k2=49) through the addition of 10 mM β-CD, or at 61 min (k2=44) using potassium dihydrophosphate as a buffer component. This method was applied for the optical purity testing of
-Ala-β-NA, which is used as one of the chiral derivatization reagents for carboxylic compounds. Validations such as reproducibility and linearity were also demonstrated and this method was found to be sufficient as a quality control method for the optical purity testing of
-Ala-β-NA. As little as 0.05%
-form in
-Ala-β-NA could be determined. 相似文献
62.
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65.
Mayumi B. Takeyama Atsushi Noya Shozo Kambara Yuichiro Hayasaka Hideaki Machida Kazuya Masu 《Applied Surface Science》2009,256(4):1222-1226
We have prepared thin Zr-B films at low temperatures as a new material applicable to an extremely thin barrier against Cu diffusion in Si-ULSI metallization. The obtained Zr-B films mainly consist of the ZrB2 phase with a nanocrystalline texture on SiO2 and a fiber texture on Cu. The resistivity of the Zr-B films depends on the substrate of SiO2 or Cu. The constituent ratio of B/Zr is almost 2, though the contaminants of oxygen, nitrogen, and carbon are incorporated in the film. The nanocrystalline structure of the Zr-B film on SiO2 is stable due to annealing at temperatures up to 500 °C for 30 min. We applied the 3-nm thick Zr-B film to a diffusion barrier between Cu and SiO2, and the stable barrier properties were confirmed. We can demonstrate that the thin Zr-B film is a promising candidate for thin film application to a metallization material in Si-ULSIs. 相似文献
66.
M. Okumura N. Nakai H. Nakamura N. Hayashi S. Yamada M. Machida 《Physica C: Superconductivity and its Applications》2009,469(15-20):932-935
In order to explore a superconducting mechanism on iron-based superconductors, we numerically study a two-band minimal model considering two degenerate dxz and dyz orbitals on Fe atom. We perform exact diagonalization on a two-band and two-leg square ladder totally composed of 10 lattice sites, which is computationally equivalent to 4-leg 20-sites square-Hubbard-ladder. Consequently, we find that a robust pairing occurs in a wide parameter range when the intra-orbital repulsive interaction becomes smaller than the inter-orbital one. Moreover, the obtained binding energy can grow into much larger value than that obtained in the single band Hubbard model depending on the parameter range. 相似文献
67.
A new geranylated aromatic compound, 5-[(2'E)-3',7'-dimethyl-2',6'-octadienyl]-4-hydroxy-6-methoxy-1-isoindolinone (1), was isolated from the fruiting bodies of the mushroom Hericium erinaceum (Bull.: Fr.) Pers. (Hericiaceae) together with three known sterols, 5alpha,6alpha-epoxy-(22E)-ergosta-8(14),22-diene-3beta,7alpha-diol (2), (22E)-ergosta-7,9(11),22-triene-3beta,5alpha,6beta-triol (3) and (22E)-ergosta-7,22-diene-3beta,5alpha,6alpha,9alpha-tetrol (4). The structure of the new compound was elucidated on the basis of spectral data. 相似文献
68.
Hideo Inaba Fujio Komatsu Akihiko Horibe Naoto Haruki Akito Machida 《Heat and Mass Transfer》2008,44(11):1305-1313
This paper describes heat and mass transfer characteristics of organic sorbent coated on heat transfer surface of a fin-tube
heat exchanger. The experiments in which the moist air was passed into the heat exchanger coated with sorption material were
conducted under various conditions of air flow rate (0.5–1.0 m/s) and the temperature of brine (14–20°C) that was the heat
transfer fluid to cool the air flow in the dehumidifying process. It is found that the sorption rate of vapor is affected
by the air flow rate and the brine temperature. Meanwhile, the attempt of clarifying the sorption mechanism is also conducted.
Finally the average mass transfer coefficient of the organic sorbent coated on heat transfer surface of a fin-tube heat exchanger
is non-dimensionalzed as a function of Reynolds number and non-dimensional temperature, and it is found that the effect of
non-dimensional temperature on them is larger than Reynolds number . 相似文献
69.
Five new monoterpene glycosides, ovatolactone 7-O-(6'-O-p-hydroxybenzoyl)-beta-D-glucopyranoside, ovatic acid methyl ester 7-O-(6'-O-p-hydroxybenzoyl)-beta-D-glucopyranoside, 7-O-p-hydroxybenzoylovatol 1-O-(6'-O-p-hydroxybenzoyl)-beta-D-glucopyranoside, 6'-O-p-hydroxybenzoylcatalposide and (2E,6R)-2,6-dimethyl-8-hydroxy-2-octenoic acid 8-O-[6'-O-(E)-p-coumaroyl]-beta-D-glucopyranoside were isolated from the fallen leaves of Catalpa ovata G. Don. Their structures were determined by extensive spectroscopic studies and syntheses. 相似文献
70.
The use of dielectric barrier discharge (DBD) plasmas has become a practical way to carry out surface treatment where precise control of the plasma parameters, such as rotational and vibrational temperatures (Trot and Tvib), is required. As the Tvib of an atmospheric pressure plasma jet appears to be the most important parameter related to the improvement of surface treatments, in this work, we analysed two methods to increase the values of Tvib in a DBD plasma jet device. One of the methods is to reduce the exit size (ø) of the DBD reactor, which results in an increase in the measured Tvib values, due to an increase in the pressure inside the reactor. The other method is to change the gas flow rate (GFR) used to produce the plasma jets. This leads to a Tvib reduction when the GFR is increased in the case of using helium or nitrogen as the working gas, but the opposite happens (an increase in the Tvib values) when argon is used, with different phenomena causing the variation of Tvib in each situation. 相似文献