著者

阿久 沢昇 南部 隼外 萩原 学 千綿 司雄 岡本 龍也 今川 博

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 (ISSN:03715345)

巻号頁・発行日

vol.2008, no.233, pp.119-123, 2008

被引用文献数

5

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The resistivity of graphite cathode in alumina molten salt was determined along with electrolysis at 945°C. The resistivity decreased monotonically with the progress of the electrolysis and finally reached to a steady value. For HTT-2000 cathode graphite, the steady value was about 70% of that of the original one before electrolysis. The resistivity turned to increase from the steady value just after interruption of the electrolysis current. A characteristic 2-step curve was observed in the resistivity vs. time plot. It increased fairly steeply at first and then became almost constant at a value corresponding to 87-88 % of that of the original value. The resistivity again increased after the plateau and finally returned to the original value. Several experiments including SEM and X-ray diffraction measurements showed that the resistivity change is closely related to the intercalation and de-intercalation of sodium. For HTT-2400 and -2800 cathode graphite, sodium concentration fixed in the matrix after electrolysis was less than that of HTT-2000.

著者

阿久沢 昇 古茂田 朋寛 玉田 耕治 平山 貴啓 今川 博

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 = Carbons (ISSN:03715345)

巻号頁・発行日

no.249, pp.191-194, 2011-09-01

参考文献数

6

被引用文献数

2

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The effect of electrolysis temperature on the resistivity change of cathode graphite during and after electrolysis of alumina molten salt was investigated. The resistivity decreased along with electrolysis and increased after the electrolysis ended. For electrolysis at 910 and 920°C, ρ/ρ₀, the resistivity normalized by the original value, decreased to ~0.80 at first and then showed a plateau at ρ/ρ₀~0.40 during electrolysis. On the other hand, for electrolysis at 950 and 980°C, only a plateau at ρ/ρ₀~0.80 was observed. Formation of the stage 8 sodium-graphite intercalation compounds was confirmed for the phase with ρ/ρ₀~0.40, in contrast to the random stage structure for the phase with ρ/ρ₀~0.80. The SEM-EDX measurement of the phase with ρ/ρ₀~0.40 showed that sodium was detected not only in the vicinity of the surface but also the inner part of the cathode. The signal intensity of sodium was almost uniform in the cross section of cathode, indicative of sodium intercalation all over the graphite. The cathode was continuously kept at the electrolysis temperature for long time after interruption of electrolysis current until the resistivity showed a steady value. The resistivity determined after cooling to room temperature was larger than that before electrolysis.

著者

佐藤 慶明

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 (ISSN:03715345)

巻号頁・発行日

vol.2014, no.261, pp.29-31, 2014

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<i>sp</i>²炭素の2次元ハニカムネットワーク構造をもつグラフェンは,その特異的な π 電子物性が注目されるとともに,現在のナノ物性科学の重要な一端を担っている。特に,原子1層の厚さしかないグラフェンでは,表面に吸着した分子がグラフェンの π 電子状態を大きく変調させるゲスト種として働き,電子輸送特性など様々な電子物性の変化が顕れる。したがって,表面分子・グラフェン間に働くホスト–ゲスト相互作用のメカニズムを理解し制御することが重要となる。本学位論文では,ゲスト種として弱い電子アクセプターとしての性質と,三重項(<i>S</i>=1)磁性を併せ持つ酸素分子に着目した。グラフェンFET (Field-Effect Transistor)デバイスにおける電子輸送特性の測定実験を通して酸素吸着効果を系統的に検証し,圧力・温度条件による酸素吸着構造の変化に応じた,様々な電子的・磁気的変調効果がグラフェン電子物性に顕れることを明らかにした。また,吸着現象もグラフェンの電子状態の影響を強く受けており,外部電場等によりグラフェンの電子密度を変調させることで,酸素吸着の挙動を制御可能であることを示した。<br>本学位論文は全6章から構成されている。第1章で本研究の背景,目的,意義を述べた後,第2章で電子輸送ならびに電荷移動反応過程の考察に必要な理論的枠組みを提供した。第3章ではグラフェン電子輸送特性に対する室温下酸素吸着効果を電子散乱・電荷移動の2点に着目して議論した。電荷移動活性のフェルミ準位依存性を反映した酸素吸着挙動変化が観測されたことを踏まえ,電気化学反応機構の知見をベースとしたグラフェン上吸着キネティクスの理論的モデル構築を行い,グラフェン等の低次元物質に対する吸着の特殊性について指摘した。第4章では第3章の結果を発展させ,グラフェンをデバイス化したときに問題となる電荷分布の空間的不均一性が室温化学吸着に与える影響について実験・理論両側面から議論し,吸着分子の空間分布制御の可能性を示唆した。第5章では,液体窒素温度以下での低温における酸素吸着(物理吸着)効果について述べ,観測された異常な磁気抵抗振動と,グラフェン伝導電子–吸着固体酸素2次元スピン格子構造間の磁気的相互作用の関連について記述した。第6章では本研究における成果をまとめ,今後の展望について述べた。本稿では,学位論文の主要部である第3章から第5章にかけて説明する。

著者

脇坂 博之 三宅 肇 河原 豊

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 (ISSN:03715345)

巻号頁・発行日

vol.2006, no.224, pp.272-275, 2006-09-01 (Released:2010-06-28)

参考文献数

19

被引用文献数

3 6

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Microporous carbons were produced by carbonizing and activating bamboo (phyllostachys heterocycla). Carbon dioxide was used as an activating agent. Also the activated carbons were produced using bamboo carbons with less potassium fractions. The potassium fractions are mainly distributing in the middle lamella that connects the adjacent cell walls of bamboo. The micropore distribution became sharper for the carbon produced using bamboo carbon with smaller potassium fractions and controlling the yield of activated carbon no less than 70%. It seems that potassium fractions in the middle lamella will accelerate the activation reaction, and then the micropore distribution tends to be broader when the activation reaction reaches the middle lamella.

著者

Susumu Yoshimura

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

TANSO (ISSN:03715345)

巻号頁・発行日

vol.1992, no.151, pp.51-58, 1992-02-20 (Released:2010-06-28)

参考文献数

33

被引用文献数

2

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Since delocalized π electrons can move about throughout a crystal or molecule without distorting it, π-electron materials have many peculiar characteristics such as extremely high electron mobility and superpolarization. The π-electron cloud is also a fundamental reaction field for organic and biological materials.The Yoshimura π-Electron Materials Project will view the large space occupied by the freely-moving π electrons as domains of electron motion and materials transformation. The project will exploit and elucidate unique physical, chemical and biochemical phenomena which result from these domains. For this, the project will develop synthetic methods and processes for new organic and inorganic materials with extended π-electron systems and with high crystallinity. It will elucidate the mechanisms of superpolarization, high electron mobility and nonlinear phenomena. The project may propose new electronic devices based on unique features of π electrons. Other work will focus on selective and/or anomalous reactions in which the π-electron domains participate. This work may shed light on mechanisms of biocompatibility and proliferation on carbonacious materials in relation to electronic structures of the π-electron systems.

著者

H.A. Yu T. Kaneko S. Otani S. Yoshimura A. Oya

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

TANSO (ISSN:03715345)

巻号頁・発行日

vol.1997, no.178, pp.101-107, 1997-07-30 (Released:2010-06-28)

参考文献数

9

被引用文献数

3 4

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It was reported that a photovoltaic cell with carbonaceous film/n-type silicon (C/n-Si) was fabricated utilizing a process in which a carbonaceous film was deposited on an n-type silicon substrate by chemical vapor deposition (CVD) of 2, 5- dimethyl-p-benzoquinone at 500°C The purpose of this work is to study preparation and structure of the carbonaceous film. In this study, the carbonaceous films were made by CVD of 2, 5-dimethyl-p-benzoquinone on a quartz substrate at a temperature between 500 and 1000°C. The 2, 5-dimethyl-p-benzoquinone shows higher reaction activity for carbonization at low temperatures. At low CVD temperatures below 700°C, the carbonization reaction of 2, 5- dimethyl-p-benzoquinone was mainly caused by pyrolysis of its methyl and carbonyl groups. The carbonaceous film deposited at low temperatures below 700°C has a typical amorphous structure, and the one deposited above 700°C has a graphite-like lamellar structure oriented along the substrate.

著者

川村 和郎 天利 光宜 有賀 敦

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 (ISSN:03715345)

巻号頁・発行日

vol.1999, no.188, pp.133-137, 1999-07-30 (Released:2011-03-01)

参考文献数

7

被引用文献数

1 2

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Carbonization behavior and density dependence of bending strength were observed onwoods and resin-impregnated woods through heat treament. Soft and hard woods were selected as the samples to which furfuryl alcohol resin was applied. The bending strength of woods were the lowest at heat treatment temperature (HTT) of around 400·Z, which was the same tendency as that for furfuryl alcohol resin. The resin impregnation did not make bending strength increase but volume shrinkage reduce. The relationship, σ=apn was recognized between the bending strength (σ) and the bulk density (p) at each HTT for all the woods examined. Also, the relationship, σ =bpm existed for each wood heat-treated at various HTTs. The exponents n and m were estimated 1.3 and 8.5, respectively. The factors a and b were dependent on HTT.

著者

Shojun Hino

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

TANSO (ISSN:03715345)

巻号頁・発行日

vol.2000, no.191, pp.80-82, 2000-02-25 (Released:2011-07-05)

参考文献数

5