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排序方式: 共有1439条查询结果,搜索用时 281 毫秒
1.
Naoto Takase Junpei Kuwabara Seong Jib Choi Takeshi Yasuda Liyuan Han Takaki Kanbara 《Journal of polymer science. Part A, Polymer chemistry》2015,53(4):536-542
The Pd‐catalyzed polycondensation of 4‐octylaniline with various dibromoarylenes was carried out under microwave heating. Microwave heating led to a decrease in the reaction time and an increase in the molecular weight of the polymers as compared to conventional heating. Microwave heating also allowed the catalyst loading to be reduced to 1 mol %, yielding polymerization results that were comparable to those under conventional heating and 5 mol % catalyst. Investigations regarding field‐effect transistors and organic photovoltaic cells using the obtained poly(arylamine) with azobenzene units revealed that increasing the molecular weight of the polymer led to improved device performance, including hole mobility and power conversion efficiency. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 536–542 相似文献
2.
Minoru Koyama Dr. Takafumi Kawakami Dr. Takashi Okazoe Prof. Dr. Kyoko Nozaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10913-10917
Methacrylic esters, represented by methyl methacrylate (MMA), are widely used as commodity chemicals. Here, the one-pot synthesis of methacrylic esters from acetone, a haloform and alcohols in the presence of an organic base is described. Using DBU as the organic base for the reaction of acetone, chloroform and methanol in acetonitrile afforded MMA in 66 % yield. When the solvent was replaced by benzonitrile, the product MMA was successfully purified by distillation. Applicability of this process to various alcohols was also investigated to show ethyl, phenyl, CF3CH2, and n-C6F13CH2CH2 esters were obtained in moderate yields. The use of bromoform instead of chloroform resulted in the improvement of the yield, for example, methyl and n-C6F13CH2CH2 esters up to 81 and 70 %, respectively. The reaction with deuterated starting materials acetone-d6 and MeOH-d4, with DBU in acetonitrile afforded deuterated MMA (MMA-d8) in 70 % yield. 相似文献
3.
Hiroyuki Saimoto Tomoyuki Onitsuka Satoko Okabe Minoru Morimoto 《Tetrahedron letters》2004,45(48):8777-8780
Treatment of 1,3-dihydroxyacetone and acrolein with aqueous KOH gave a tetrahydrofuran derivative, 1,4-dihydroxy-3,7-dioxabicyclo[3.3.0]octane, in 80% yield. Similarly, 6-alkyl substituted 1,4-dihydroxy-3,7-dioxabicyclo[3.3.0]octanes were obtained by reaction of 1,3-dihydroxyacetone with various α,β-unsaturated aldehydes. In the cases of long chain alkenals, the reaction was effectively accelerated in the presence of organic co-solvent. On the other hand, the corresponding tricyclic products were synthesized by reaction of 1,3-dihydroxyacetone with cyclic enones, such as 2-cyclopentenone and 2-cyclohexenone. This method was successfully applied to the reaction of a tetrulose in the absence of any protecting groups. 相似文献
4.
Yasushi Seike Ryoko Fukumori Yukiko Senga Hiroki Oka Kaoru Fujinaga Minoru Okumura 《Analytical sciences》2004,20(1):139-142
A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively. 相似文献
5.
Minoru Itoh 《Mathematische Zeitschrift》2004,246(1-2):125-154
6.
Sub-critical crack growth rates of soda-lime-silicate glass and less brittle glass with different fictive temperatures were compared using the DCDC method under both dry and humid atmospheres in order to investigate the origin of the unique mechanical features of the less brittle glass developed by Ito and his collaborators. In both dry and humid atmospheres, the crack velocity of the soda-lime-silicate glass was slower than that of the less brittle glass. For both glasses, the glass sample with higher fictive temperature showed a slower crack growth rate under both dry and humid atmospheres. These observations can be explained by the tendency for the plastic flow at the crack tip; the soda-lime-silicate glass is expected to show easier plastic flow under tension than the less brittle glass, and also the samples with higher fictive temperatures are expected to show easier plastic flow, leading to greater fracture toughness, KIC, and slower crack growth rate. 相似文献
7.
This paper presents a method of measuring a light field of a light source with high directional resolution using a mirrored
ball and a pinhole camera. The light field describes a spatial and directional distribution of radiances from the light source.
The directional distribution is expanded by a reflection on the mirrored ball, and the radiances are measured by a charge-coupled
device (CCD) camera with a pinhole lens. The light source is laterally moved by a robot arm to measure the directionally expanded
light field, and each pixel on a CCD can obtain the radiances from the light source through the pinhole lens with high directional
resolution. The light field is estimated from the pixel value and the position of each pixel using a ray tracing technique.
The light field of a krypton lamp was experimentally measured by the proposed method, and the accuracy of the measurement
was evaluated against the irradiances measured by a spectro-radiometer at sample points. 相似文献
8.
Kimihiko SatoTsutomu Kishimoto Minoru MorimotoHiroyuki Saimoto Yoshihiro Shigemasa 《Tetrahedron letters》2003,44(47):8623-8625
A simple method for the hydrolysis of acetals and ketals was accomplished in neutral water or aqueous media by hydrothermal treatment without using acidic reagents. The deacetalization reaction was effectively accelerated in the presence of calcium chloride. Because no acidic catalysts were employed, neutralization of the reaction mixture was not necessary after the reaction. This sequence was successfully applied to the hydrolysis of chitosan, a biodegradable polyaminosaccharide. 相似文献
9.
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