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排序方式: 共有237条查询结果,搜索用时 31 毫秒
101.
Tomokazu Ohya Aki Nakayama Yukio Shibata Takayuki Ban Yutaka Ohya Yasutaka Takahashi 《Journal of Sol-Gel Science and Technology》2003,26(1-3):799-802
Dip- or spin-coating and characterization of titania (TiO2) thin films from various aqueous solutions have been studied. The aqueous titanium solutions mainly used in this study were halogen- and chelate-free solutions with the concentrations up to 1.4 M derived from titanium isopropoxide (TIP) with tetramethylammonium hydroxide (TMAOH) or some alkylamines, while aqueous and alcoholic solutions containing titanium atoms stabilized chelating ligands were examined for comparison. The TiO2 films prepared from the TIP-TMAOH solution were already crystallized at 350°C to anatase form and those formed at 600°C had high transparency and refractive indices of 2.40. No carbon residue in the film prepared at 400°C was detected by XPS. The pure anatase form was sustained up to 850°C. Interestingly, it was found that the (004) preferentially oriented anatase films were obtained from TIP-lactic acid (LA) system until 700°C. The solutions containing citric acid (CA) or alkanolamines yielded anatase and rutile form fired at the temperatures equal to or higher than 600°C. Carbon residue was detected in the film fired at 400°C. The film thickness monotonically decreased from the upper to the bottom ends of the substrate. However, it was found that the thickness uniformity was drastically improved by an addition of sucrose to the aqueous solutions. The effects of the solution composition and polyhydroxy compounds on the crystal modifications of formed films and the film uniformity are discussed. 相似文献
102.
Aki Hayashi Hirokazu Nakayama Mitsutomo Tsuhako Taro Eguchi Nobuo Nakamura 《Journal of inclusion phenomena and macrocyclic chemistry》1999,34(4):401-412
Intercalation of ,-alkanediamines, NH2(CH2)
n
NH2 (n = 3–10), into layered aluminium dihydrogen triphosphate dihydrate, AlH2(P3(O10... 2H2O, was investigated by XRD, DTA-TG, elemental analysis, and solid-state 31P, 13C and 27Al NMR. ,-Alkanediamines are intercalated to form a monomolecular layer in the interlayer region, in which the alkanediamines incline at 57 ± 5° to the phosphate layers, whereas n-alkylamines form a bilayer structure with the same inclination angle. Two amino groups in an ,-alkanediamine molecule bridge the layered sheets of phosphates. 相似文献
103.
Terao J Watanabe H Ikumi A Kuniyasu H Kambe N 《Journal of the American Chemical Society》2002,124(16):4222-4223
A new method for the cross-coupling reaction of Grignard reagents with alkyl chlorides, bromides, and tosylates has been developed by the use of a nickel catalyst in the presence of a diene as an additive. This reaction proceeds efficiently at 0-25 degrees C in THF using primary and secondary alkyl and aryl Grignard reagents. Nickel complexes bearing no phosphine ligands, such as NiCl2, Ni(acac)2, and Ni(COD)2, afford the coupling products in good yields, whereas NiCl2(PPh3)2 and NiCl2(dppp) were less effective. 1,3-Butadiene shows the highest activity as an additive for the present coupling reaction. A plausible reaction pathway was proposed. 相似文献
104.
Yoshio Imai Kazuo Itoya Masami Kanamaru Masa‐Aki Kakimoto 《Journal of polymer science. Part A, Polymer chemistry》2002,40(11):1790-1795
New phenolic hydroxyl‐pendant aromatic polyimides were synthesized with the N‐silylated diamine method in two steps: the ring‐opening polyaddition of tetrakis(trimethylsilyl)‐substituted 4,4′‐diamino‐3,3′‐dihydroxybiphenyl to various aromatic tetracarboxylic dianhydrides, giving trimethylsiloxy‐pendant poly(amic acid) trimethylsilyl esters, and thermal imidization. The hydroxyl‐bearing polyimides were amorphous but insoluble in organic solvents. They had glass‐transition temperatures greater than 370 °C and temperatures of 10% weight loss greater than 415 °C in nitrogen. The hydroxyl‐pendant polypyromellitimide film had a high tensile strength and a high modulus of 310 MPa and 10 GPa, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1790–1795, 2002 相似文献
105.
Sigeo Aki 《Annals of the Institute of Statistical Mathematics》1981,33(1):1-14
Summary In this paper we investigate the effect of estimating the center of symmetry on a Cramér-von Mises type statistic for testing
the symmetry of a distribution function. The test statistic is defined by
whereF
n is the empirical distribution function andS[F
n] is an estimator of the center ofF which is consistent with the ordern
1/2 and has von Mises derivative. The asymptotic distribution ofnT
0[Fn] under the null hypothesis is obtained. The distribution depends on the distributionF and on the estimatorS[F
n].
The Institute of Statistical Mathematics 相似文献
106.
The insertion reaction of isocyanide into a C-S bond of dithioacetals is catalyzed by GaCl3 or TiCl4 to afford thioimidates containing an alpha-alkylthio group. Balanced thiophilicity of these Lewis acids is critical for efficient catalysis. 相似文献
107.
Shimada Y Goto T Kawamoto S Kiso T Katayama A Yamanaka Y Aki T Chiang KC Nakano T Goto S Chen CL Ohmori N Ono K Sato S 《Biomedical chromatography : BMC》2008,22(1):13-19
In organ transplantation, the development of a novel immunosuppressant free of the need for permanent administration and any serious side effects has eagerly been awaited. We have previously reported that an anti-histone H1 polyclonal antibody has immunosuppressant activity. Here we prepared an anti-histone H1 monoclonal antibody as an analytical tool to elucidate its mechanism of immunosuppression. The isotype of this monoclonal antibody was immunoglobulin M. A monoclonal antibody prepared for administration to organ transplantation model animals should not contain any allogenic proteins and should have high purity. Therefore, we conducted a two-step chromatography procedure, consisting of strong anion-exchange chromatography and gel filtration chromatography, to purify an anti-histone H1 monoclonal immunoglobulin M antibody from the serum-free culture supernatant of hybridomas. Consequently, we successfully purified the monoclonal antibody at 96%, a purification rate at which its administration to organ transplantation model animals is possible. 相似文献
108.
7-Acylaminocephalosporanic acid derivatives (1) were converted into 7-acylamino-3-methylenecepham-4-carboxylic acids (2) by treatment with chromium(II) salts in aqueous media. The esters (4a or 4b) of 7-acylamino-3-methylenecepham compounds were readily isomerized to the 3-methyl-3-cephem compounds (5a or 5b) under basic conditions. The reaction mechanism is discussed. 相似文献
109.
110.