http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : KUN'ICHI MIYAZAWA (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
GROWTH RATE MEASUREMENT OF C60 FULLERENE NANOWHISKERS
KAYOKO HOTTA,KUN’ICHI MIYAZAWA 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.5
The growth rate of C60 fullerene nanowhiskers (C60NWs) prepared by the liquid–liquid interfacial precipitation method is measured and the growth mechanism is discussed. The growth of C60NWs is investigated from the data obtained at the growth temperatures of 5, 10, 15 and 20°C. It is found that the convection of the solution scarcely influences the growth rate, suggesting that a surface reaction of C60 molecules dominates the growth process. The activation energy of C60NWs' growth is estimated at about 52.8 kJ/mol from their initial stage of growth. This activation energy is much greater than that of C60 diffusion in solutions found in the literature. This result suggests that the desolvation process of C60 on the whisker surface governs the growth of C60NWs.
-
ORGANIC-METAL-DOPED FULLERENE NANOWHISKERS
TOSHIO SASAKI,KUN'ICHI MIYAZAWA 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.5
Two types of ferrocene(Fc)-doped C60 nanowhiskers [C60/Fc NWs and C60/ferrocene pyrrolidine-C60(C60-Fc) NWs] were prepared by the liquid–liquid interfacial precipitation method using toluene solution of C60 and Fc or C60-Fc and isopropyl alcohol (IPA). The morphology of C60 precipitates was remarkably changed by the addition of Fc or C60-Fc to the C60 toluene solution. The scanning TEM mapping analysis of C60/Fc NWs showed that the intensity of ferrocene is high at the edge, indicating that ferrocene covers the outside surface of the NWs. In the case of C60/C60-Fc NWs, however, the scanning TEM mapping analysis showed that C60-Fc disperses well in the NWs.
-
Kinetically controlled fabrication of C60 1-dimensional crystals.
Cha, Seung I,Miyazawa, Kun'ichi,Kim, Yun K,Lee, Dong Y,Kim, Je-Deok American Scientific Publishers 2011 Journal of Nanoscience and Nanotechnology Vol.11 No.4
<P>Considering the current application of fullerenes in the field of organic semiconductor devices, the highly crystalline or single crystal fullerene nanostructures with controlled shape and size contains some breakthrough for improved efficiency. Recently, fullerene 1-dimensional nanostructures, including nanowhiskers and nanotubes, become attractive kind of materials since the development of liquid-liquid interface precipitation (LLIP) process. The LLIP process has critical advantage; the fabrication of highly crystalline, even single crystal, fullerene 1-dimensional nanostructures with simple apparatus. However, the fabrication fullerene 1-dimensional structures by LLIP process requires long process time from one day to several days. In order to overcome this drawback, a modified process from conventional LLIP process is suggested. In the modified LLIP process, the nucleation step and growth step were divided. For the nucleation step, saturated fullerene solution is mixed with small amount of alcohols such as 2-propanol or ethanol. For the controlled growth step, the fullerenes in the nucleated solution are precipitated by addition of alcohol, which is injected to the bottom of the solution with controlled flow rate. In this modified process, the shape of the precipitated fullerene crystals is critically dependent on the nucleation steps and the size is dependent on the precipitation rate. By combination of proper nucleation step and growth rate, a well defined fullerene 1-dimensional structures, of 200-500 nm width and of hundreds microm length can be fabricated within two hours. In addition, by controlling injection rate and degree of supersaturation, several types of 1-dimensional structures including micro-tubes can be prepared and, by changing solvent and alcohol, several shape of C60 crystals including polyhedral particles and plates can be prepared.</P>
-
HIGH YIELD PREPARATION OF FULLERENE NANOWHISKERS AND NANOTUBES BY THE SOLUTION ROUTE
CHERRY L. RINGOR,KUN'ICHI MIYAZAWA 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.5
The effect of ultraviolet, visible and near-infrared irradiation on the yield and morphology of single crystalline C60 fullerene nanowhiskers (FNWs) and nanotubes (FNTs) was investigated in an effort to produce large-scale quantities of FNWs and FNTs. These fullerene nanomaterials were synthesized by the liquid–liquid interfacial precipitation method using pyridine and isopropyl alcohol (IPA) as solvents. The C60–pyridine solution was illuminated using different wavelengths for 24 h at ambient pressure and temperature before addition of IPA. High yields (30–38 mg/L) were obtained upon irradiation using wavelengths in the ultraviolet region in accordance with the increased photoabsorption signal of solid C60 and C60 dissolved in pyridine acquired by a UV-VIS-NIR spectrophotometer. However, elevated yields (21–27 mg/L) were also obtained in the 600–800 nm regions, where C60 absorption is particularly weak. Such an enhanced yield of FNTs and FNWs is probably related to the reported rise in transient absorption of the triplet excited state of C60 in the 740 nm region formed by the decay of the photoexcited singlet C60 through intersystem crossing. The formation of photopolymerized fullerene nanofibers was also observed by Raman spectroscopy, it is attributed to ultraviolet and visible light irradiation. SEM and TEM observations suggest that preparation of FNWs and FNTs by irradiation using different wavelengths of light does not produce apparent morphological transformations on the surface of these fullerene materials.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
