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排序方式: 共有95条查询结果,搜索用时 0 毫秒
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Large-scale separation of metallic and semiconducting single-walled carbon nanotubes 总被引:6,自引:0,他引:6
Maeda Y Kimura S Kanda M Hirashima Y Hasegawa T Wakahara T Lian Y Nakahodo T Tsuchiya T Akasaka T Lu J Zhang X Gao Z Yu Y Nagase S Kazaoui S Minami N Shimizu T Tokumoto H Saito R 《Journal of the American Chemical Society》2005,127(29):10287-10290
In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way. 相似文献
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Unsymmetrical oxamides are conveniently synthesized in good yields by a new trapping reaction of unstable carbamoyl lithiums with isocyanates. 相似文献
5.
Hirashima A Shinkai K Kuwano E Taniguchi E Eto M 《SAR and QSAR in environmental research》2000,11(1):45-54
The quantitative structure-activity relationship of 39 octopamine (OA) agonists and 12 antagonists against the thoracic nerve cord of the migratory locust, Locusta migratoria L. was analyzed using atom based rigid fit method or flexible fitting offered by PowerFit 1.0 from MicroSimulation. For OA agonists, the more similar to reference compound NC (24) the structure of test compound, the higher the activity, whereas for OA antagonists it was not the case. Antagonists may not interact with the same part of the membrane with which the agonists interact. Taken the part of the membrane with which the agonist interacts as the true receptor, the antagonist may well interact with an area surrounding the receptor including the ionophore. 相似文献
6.
Koichi Funazo Takayuki Hirashima Minoru Tanaka Toshiyuki Shono 《Fresenius' Journal of Analytical Chemistry》1982,311(1):27-29
Summary A method is described for the determination of sulphide ion in aqueous samples by gas chromatography. Sulphide is ethylated with diethyl sulphate and the resulting diethyl sulphide is extracted with chloroform and determined with a gas chromatograph equipped with a flame ionization or a flame photometric detector. In the case of a flame photometric detector, the detection limit for sulphide ion is 0.05 g/ml. Other anions commonly found with sulphide ion do not interfere. Sulphide ion in spring waters was analysed by this new method and for comparison also by colorimetry (methylene blue). The results revealed the reliability of the new method.
Bestimmung von Sulfidspuren durch Ethylierung und Gas-Chromatographie
Zusammenfassung Sulfid wird mit Diethylsulfat ethyliert, das gebildete Diethylsulfid mit Chloroform extrahiert und gaschromatographisch mit Hilfe eines Flammenionisationsoder eines flammenphotometrischen Detektors bestimmt. Die Nachweisgrenze beträgt 0,05 g S/ml für den FPD. Anionen, die üblicherweise mit Sulfid zusammen vorkommen, stören nicht. Das Verfahren wurde, im Vergleich mit der colorimetrischen Methylenblaumethode, auf Quellwasser angewendet. Es wurde gute Übereinstimmung der Ergebnisse erzielt.相似文献
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The passages of vapor flow and the returning liquid flow, are perfectly partitioned in a separate thermosyphon. Therefore the flooding limit can be eliminated, and practicability based on its construction is highly evaluated. In the present work, a container tube made of heat resisting glass, in which an electric heater is inserted, is selected as the heating section of the experimental equipment. Distilled water is used as the working fluid. The influence of the heater type, the diameter of evaporating section and the liquid fill charge on the heat transfer performance have been studied. The larger heat transfer coefficient is achieved in the case of the U type heater, the larger tube diameter and the less liquid fill charge of the evaporating section. The useful correlation equations of the heat transfer coefficient in the evaporator have been derived.
Experimentelle Untersuchung an einem Trennstrom-Thermosiphon
Zusammenfassung In einem Trennstrom-Thermosiphon sind die Strömungskanäle für die Dampfströmung und den Kondensatrücklauf vollkommen separiert. Die Flutgrenze kann deshalb unberücksichtigt bleiben. In dieser Untersuchung dient ein temperaturbeständiges Glasrohr mit innenliegender Heizung als Wärmequelle. Arbeitsmedium ist destilliertes Wasser. Untersucht wurden der Einfluß des Heizelementtyps, des Durchmessers der Verdampferstrecke und der Füllmenge auf das Wärmeüber-gangsverhalten. Das U-Typ Heizelement liefert bei größerem Rohrdurchmesser und geringerer Füllmenge in der Verdampferstrecke die höchsten Wärmeübergangskoeffizienten. Für diese wurden Korrelationsgleichungen aufgestellt.相似文献
10.
A. Venkateswara Rao Uzma K. H. Bangi Sunetra L. Dhere Hiroaki Imai Hiroshi Hirashima 《Journal of Sol-Gel Science and Technology》2011,57(1):95-100
The effect of iron acetylacetonate on the physico-chemical properties of waterglass based silica aerogels by ambient pressure
drying has been investigated. Doping the gels with iron acetylacetonat (FeAA) facilitates in the diminution of the density
of the aerogels. The well established silica network provides effective confinement of FeAA nanoparticles which resists the
collapse of silica network during ambient pressure drying. Therefore, in the present paper, the effects of FeAA on the physico-chemical
properties of the aerogels have been studied by varying the FeAA:Na2SiO3 molar ratio from 3 × 10−4 to 6 × 10−4. The aerogels were prepared via ambient pressure drying and characterized by the bulk density, thermal conductivity and water
contact angle. The aerogel’s surface morphology, elemental analysis and pore structure were characterized by means of EDAX
and FTIR, TEM and N2 adsorption- desorption analyzer. The high temperature hydrophobicity of these aerogels was checked by heating them in temperature
controlled furnace. Silica aerogels with low density ~0.050 g/cc have been obtained using the molar ratio of Na2SiO3:H2O:FeAA:Citric acid:TMCS at 1:146.67:3 × 10−4:0.54:9.46, respectively. EDAX and FTIR studies show that the iron species are entrapped in the mesoporous framework and not
took part in the bonding with silica. 相似文献