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排序方式: 共有109条查询结果,搜索用时 15 毫秒
1.
Takakazu Yamamoto Kouichi ShiraishiMahmut Abla Isao YamaguchiL.“Bert” Groenendaal 《Polymer》2002,43(3):711-719
Neutral and non-doped poly(3,4-ethylenedioxythiophene), PEDOTh(Ni), and its hexyl derivative, PEDOTh-C6(Ni), have been prepared by organometallic dehalogenation polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene and its hexyl derivative with a zerovalent nickel complex. PEDOTh-C6(Ni) was soluble in organic solvents and 1H NMR data indicated that it had an Mn of 11,000. MALDI-TOF mass analysis of PEDOTh(Ni) gave Mn and Mw of about 1700 and 2400, respectively. PEDOTh-C6(Ni) showed a UV-Vis absorption peak at 546 nm in CHCl3. Electrochemical oxidation of PEDOTh-C6(Ni) started at about −0.40 V vs Ag+/Ag and gave a peak at 0.20 V vs Ag+/Ag. Chemical and electrochemical oxidation (or p-doping) of PEDOTh-C6(Ni), both in solutions and in a solid state, led to weakening of the original π-π∗ peaks and rise of new peak(s) in a region of 800-1500 nm. The p-doping of PEDOTh-C6(Ni) caused not only a decrease in the intensity of 1H NMR signals of the bridging ethylene hydrogens but also a decrease in that of the hexyl side chain, suggesting a strong interaction of the p-dopant with the side chain. NMR data of poly(3-methoxythiophene-2,5-diyl) also supported an assumption that p-doping brings about a severe change in electronic state of the substituent attached to the polythiophene main chain. PEDOTh(Ni) had a density of 1.71 g cm−3; the molecular packing mode of PEDOTh(Ni) is discussed based on the density of the polymer and its XRD data. 相似文献
2.
Takaki Kanbara Takakazu Yamamoto Hiroyuki Ikawa Tomohiko Tagawa Hisao Imai 《Journal of Materials Science》1989,24(5):1552-1558
Porous and electrically conducting carbon-clay composites were prepared by firing mixtures of carbon powder (0 to 20 wt%) and clay minerals. They showed porosity of 50 to 65% and had high mechanical strength (compressive strength = 130 to 400 kg cm–2) as well as high resistance against thermal oxidation in air. Their electrical conductivity, , increased with increasing carbon content levelling off at about 20 wt% of carbon content to give a value of about 2 S cm–1. Formation of carbon chains is considered to be responsible for the electrical conduction in the composite, and a model to correlate the electrical conductivity with the carbon content has been proposed by modifying a model previously proposed by Scarisbrick. 相似文献
3.
Dr. Daisuke Okuno Dr. Noriho Sakamoto Dr. Mohammed S. O. Tagod Yoshiko Akiyama Dr. Sakiko Moriyama Dr. Takuto Miyamura Dr. Atsuko Hara Dr. Takashi Kido Dr. Hiroshi Ishimoto Prof. Yuji Ishimatsu Prof. Takashi Tanaka Prof. Jun Ishihara Prof. Kohsuke Takeda Prof. Yoshimasa Tanaka Prof. Hiroshi Mukae 《ChemMedChem》2021,16(16):2515-2523
Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is causally related to fibrotic diseases, including idiopathic pulmonary fibrosis. The identification of Compounds that interfere with the HSP47-collagen interaction is essential for the development of relevant therapeutics. Herein, we prepared human HSP47 as a soluble fusion protein expressed in E. coli and established an assay system for HSP47 inhibitor screening. We screened a natural and synthetic Compound library established at Nagasaki University. Among 1023 Compounds, 13 exhibited inhibitory activity against human HSP47, of which three inhibited its function in a dose-dependent manner. Epigallocatechin-3-O-gallate, one of these three Compounds, is a typical polyphenol Compound derived from tea leaves. Structurally related Compounds were synthesized and examined for their activity, revealing a hydroxyl group at A-ring position 5 as important for its activity. The present findings provide valuable insight for the development of natural product-derived therapeutics for fibrotic diseases, including idiopathic pulmonary fibrosis. 相似文献
4.
A -conjugated polymer, poly(pyridine-2,5-diyl) (PPy) was investigated as a support for CuCl2 in the synthesis of dimethyl carbonate by oxidative carbonylation of methanol. The PPy–CuCl2 adduct had high catalytic activity which was comparable to that of the homogeneous CuCl2 catalyst. The adduct caused corrosion of stainless-steel vessels only to minor extent, compared with the homogeneous CuCl2 catalyst. This PPy–CuCl2 catalyst was easily recycled by filtration and showed a similar catalytic activity in the third time use. The presence of the -conjugated system in PPy, through which electrons can move, may bring about the high catalytic activity for the oxidative carbonylation of methanol, which involves Cu(II)/Cu(I) redox processes. 相似文献
5.
Summary Dehalogenation polycondensations of 2,7-dibromo-9,10-dihydrophenanthrene with isolated zero-valent nickel complex and electrochemically generated zero-valent nickel complex afford -conjugated poly(9,10-dihydrophenanthrene-2,7-diyl). The electrochemically synthesized polymer is obtained as a thin film on electrode, and shows a reversible electrochemically doping-undoping cycle in an oxidation region. The polymer has essentially the same -conjugation system as that of poly(p-phenylene). 相似文献
6.
An advanced coded imaging system is described, and some results of phantom experiments are presented. The advanced method uses a pair of coherent codes (+ 1 and -1 codes) and has many advantages compared with conventional ones. One of the greatest advantages is that there are no sidelobes in the focal plane and only a few in other planes. Therefore, when an object can be regarded as two-dimensional, it is perfectly reconstructed with high detecting efficiency, and this is successfully simulated by a thyroid phantom with 99mTc. Moreover, this system has an ability to reconstruct tomograms, which is also shown by using ring phantoms piled on one another with some cold spots in their shells. From these experimental results it may be concluded that the new system is useful for practical applications, for example, to nuclear medicine. 相似文献
7.
Kazufumi Tsujimoto Toshinobu Sasa Kenji Nishihara Takakazu Takizuka Hideki Takano 《Progress in Nuclear Energy》2000,37(1-4):339-344
The accelerator-driven transmutation system has been studied at the Japan Atomic Energy Research Institute. This system is a hydrid system which consists of a high intensity accelerator, a spallation target and a subcritical core region. In the conceptual design study, two types of system concepts, sodium cooled and lead-bismuth cooled system, are being studied. In this study, we fucus on our lead-bismuth cooled accelerator-driven transmutation system to investigate basic characteristics. The fuel compositions were optimized for efficient transmutation of minor actinide. The transmutation of long-lived fission products was also considered. 相似文献
8.
This paper presents an autonomous wheelchair system with the capability of self-location and obstacle avoidance. The wheelchair
is equipped with two TV cameras that are used for self-location and obstacle avoidance, respectively. In this system, the
fluorescent ceiling lights are chosen as landmarks since they can be easily detected and do not require an additional installation.
A recognition procedure of landmarks is described by which the desired landmark images in the navigational environment can
be retrieved. A self-location technique using ceiling light landmarks is proposed. Using this self-location function, the
wheelchair can locate itself in a world coordinate system. The path planning based on landmark and the method of generating
a control scheme are presented so that the wheelchair is capable of navigating along any path from start position to goal
position. A low cost and high-speed vision system for the detection and avoidance of obstacle is developed and the principal
of obstacle avoidance is introduced. A number of navigation experiments are conducted for the wheelchair in an indoor environment.
The experimental results indicate the effectiveness of the wheelchair system. 相似文献
9.
研究了在不同条件下以NiCl2(bpy)为催化剂的对-二溴苯与间-二溴苯间的共缩聚反应。利用该反应可以合成出数均分子量为2400的一系列共聚物,而且部分试样在有机溶剂中具有良好的溶解性。红外光谱和紫外光谱分析表明:在共聚物中存在着对苯撑与间苯撑结构单元。DSC、TGA和X-ray分析表明:随着共聚物中间苯撑结构单元的增加,聚苯撑共聚物的玻璃化转移温度、粘流温度和结晶度降低。共聚物的四氢呋喃溶液的荧光光谱分析表明:发射光谱的最大值处于373-376nm处。而同一试样的膜,该值位移到405-436nm处。 相似文献
10.
Summary
The reactions of α,ω-diyne, HC≡C(CH2)mC≡CH (m = 6 and 8), with 3,3'-diaminobenzidine and with 3,3'-diamino-4,4'-dihydroxybiphenyl in the presence of RU3(CO)12-PPh3 catalyst give the corresponding poly(alkylenebenzoxazole)s and poly(alkylenebenzimidazole)s, respectively. The former polymers
obtained from the equimolar reaction of the monomers are partly soluble in polar organic solvents such as DMF, DMSO, and NMP,
while the poly(benzimidazole)s are soluble in these solvents. GPC measurement shows the molecular weights of the polymers,
M
n of 4.8−14.1×103 and M
w of 6.4−19.7×103.
Received: 24 November 1998/Revised version: 21 December 1998/Accepted: 24 December 1998 相似文献