Nobuo Takahashi

Publications (11)23.77 Total impact

• Article: Chemical Shift Changes and Line Narrowing in (13)C NMR Spectra of Hydrocarbon Clathrate Hydrates.

  Masato Kida, Hirotoshi Sakagami, Nobuo Takahashi, Jiro Nagao
  [show abstract] [hide abstract]
  ABSTRACT: The solid-state 13C NMR spectra of various guest hydrocarbons (methane, ethane, propane, adamantane) of clathrate hydrates were measured to elucidate local structural environments around hydrocarbon molecules isolated in guest-host frameworks of clathrate hydrates. Results show that, depending on the cage environment, trends in the 13C chemical shift and in the line width change as a function of temperature. Shielding around the carbons of the guest normal alkanes in looser cage environments tends to decrease with increasing temperature, although shielding in tighter cage environments tends to increase continuously with increasing temperature. Furthermore, the 13C NMR line widths suggest that the local structures, because of the reorientation of the guest alkanes in structure II, are more averaged than those in structure I. Differences between structures I and II tend to be remarkably large in the lower temperature range examined in this study. The 13C NMR spectra of adamantane guest molecules in structure H hydrate show that the local structures around adamantane guests trapped in structure H hydrate cages are averaged at the same level as the phase α solid adamantane.
  The Journal of Physical Chemistry A 04/2013; · 2.95 Impact Factor
• Source

  Available from: Akihiro Hachikubo

  Article: Molecular and isotopic characteristics of gas hydrate-bound hydrocarbons in southern and central Lake Baikal

  Akihiro Hachikubo, Oleg Khlystov, Alexey Krylov, Hirotoshi Sakagami, Hirotsugu Minami, Yutaka Nunokawa, Satoshi Yamashita, Nobuo Takahashi, Hitoshi Shoji, Shin’ya Nishio, Masato Kida, Takao Ebinuma, Gennadiy Kalmychkov, Jeffrey Poort
  [show abstract] [hide abstract]
  ABSTRACT: We investigated the molecular composition (methane, ethane, and propane) and stable isotope composition (methane and ethane) of hydrate-bound gas in sediments of Lake Baikal. Hydrate-bearing sediment cores were retrieved from eight gas seep sites, located in the southern and central Baikal basins. Empirical classification of the methane stable isotopes (δ13C and δD) for all the seep sites indicated the dominant microbial origin of methane via methyl-type fermentation; however, a mixture of thermogenic and microbial gases resulted in relatively high methane δ13C signatures at two sites where ethane δ13C indicated a typical thermogenic origin. At one of the sites in the southern Baikal basin, we found gas hydrates of enclathrated microbial ethane in which 13C and deuterium were both highly depleted (mean δ13C and δD of –61.6‰ V-PDB and –285.4‰ V-SMOW, respectively). To the best of our knowledge, this is the first report of C2 δ13C–δD classification for hydrate-bound gas in either freshwater or marine environments.
  Geo-Marine Letters 04/2012; 30(3):321-329. · 1.47 Impact Factor
• Article: 13C chemical shifts of propane molecules encaged in structure II clathrate hydrate.

  Masato Kida, Akira Hori, Hirotoshi Sakagami, Satoshi Takeya, Yasushi Kamata, Nobuo Takahashi, Takao Ebinuma, Hideo Narita
  [show abstract] [hide abstract]
  ABSTRACT: Experimental NMR measurements for (13)C chemical shifts of propane molecules encaged in 16-hedral cages of structure II clathrate hydrate were conducted to investigate the effects of guest-host interaction of pure propane clathrate on the (13)C chemical shifts of propane guests. Experimental (13)C NMR measurements revealed that the clathrate hydration of propane reverses the (13)C chemical shifts of methyl and methylene carbons in propane guests to gaseous propane at room temperature and atmospheric pressure or isolated propane, suggesting a change in magnetic environment around the propane guest by the clathrate hydration. Inversion of the (13)C chemical shifts of propane clathrate suggests that the deshielding effect of the water cage on the methyl carbons of the propane molecule encaged in the 16-hedral cage is greater than that on its methylene carbon.
  The Journal of Physical Chemistry A 02/2011; 115(5):643-7. · 2.95 Impact Factor
• Article: Dissociation behavior of methane--ethane mixed gas hydrate coexisting structures I and II.

  Masato Kida, Yusuke Jin, Nobuo Takahashi, Jiro Nagao, Hideo Narita
  [show abstract] [hide abstract]
  ABSTRACT: Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II simultaneously convert to Ih during the dissociation, but the diffraction pattern at temperatures greater than 208 K showed different dissociation behavior between structures I and II. Although the diffraction peaks from structure II decreased during measurement at constant temperatures greater than 208 K, those from structure I increased at the initial step of dissociation and then disappeared. This anomalous behavior of the methane-ethane mixed gas hydrate coexisting structures I and II was examined by using the (13)C NMR technique. The (13)C NMR spectra revealed that the anomalous behavior results from the formation of ethane-rich structure I. The structure I hydrate formation was associated with the dissociation rate of the initial methane-ethane mixed gas hydrate.
  The Journal of Physical Chemistry A 09/2010; 114(35):9456-61. · 2.95 Impact Factor
• Source

  Available from: Akihiro Hachikubo

  Article: Lattice expansion of clathrate hydrates of methane mixtures and natural gas.

  Satoshi Takeya, Tsutomu Uchida, Yasushi Kamata, Jiro Nagao, Masato Kida, Hirotsugu Minami, Hirotoshi Sakagami, Akihiro Hachikubo, Nobuo Takahashi, Hitoshi Shoji, Oleg Khlystov, Mikhail Grachev, Valery Soloviev
  Angewandte Chemie International Edition 11/2005; 44(42):6928-31. · 13.45 Impact Factor
• Article: 補聴器がもたらす音の大きさの感覚特性　：　高調波歪との関係

  信雄 高橋, Nobuo Takahashi, ノブオ タカハシ
  [show abstract] [hide abstract]
  ABSTRACT: http://www.tulips.tsukuba.ac.jp/mylimedio/dl/page.do?issueid=411670&tocid=100057800&page=27-34
• Article: ＥＵ統合下におけるトゥールーズ大都市圏の構造変容

  伸夫 高橋, 章 手塚, 祐司 村山, 篤志 平, 公明 松村, 圭介 松井, 宏信 小田, Nobuo Takahashi, Akira Tezuka, Yuji Murayama, ノブオ タカハシ, アキラ テズカ, ユウジ ムラヤマ
  [show abstract] [hide abstract]
  ABSTRACT: これまで同様なタイトルのもとで、われわれの研究グループはリール大都市圏とリヨン大都市圏の構造変容について、それぞれの特徴を指摘してきた(高橋･手塚、2000;高橋伸夫ほか、2001)．トゥールズ大都市圏は、リール大都市圏やリヨン大都市圏とともに、フランスの周辺部に位置するという共通性を ... http://www.tulips.tsukuba.ac.jp/mylimedio/dl/page.do?issueid=578821&tocid=100033236&page=45-80
• Article: 水戸市中心市街地における商業地域構造と地域活性化

  純 兼子, 亜紀郎 山下, 健一 豊島, 珠州彦 高橋, 正樹 川瀬, 伸夫 高橋, Jun Kaneko, Akiro Yamashita, Kenichi Toyoshima, Shuhiko Takahashi, Masaki Kawase, Nobuo Takahashi, ジュン カネコ, アキロウ ヤマシタ, ケンイチ トヨシマ, シュウヒコ タカハシ, マサキ カワセ, ノブオ タカハシ
  [show abstract] [hide abstract]
  ABSTRACT: I はじめに 近年、中心市街地の活性化に関する議論が各分野でなされている。中心市街地は商業、業務、居住等の都市機能が集積し、文化や伝統を育む「まちの顔」ともいえる地域であり、にぎわいが欠かせない場所である。しかし近年、モータリゼーションへの対応の遅れや、商業を取り巻く環境の変化による商店街の衰退 ... http://www.tulips.tsukuba.ac.jp/mylimedio/dl/page.do?issueid=578823&tocid=100033415&page=1-31
• Article: オホーツク海のメタンハイドレート含有層における間隙水の地球化学

  尚嗣 南, Alexey Krylov, 寛敏 坂上, 晶弘 八久保, 欣二 百武, 仁 戸丸, 真人 木田, 信夫 高橋, 仁 庄子, Tatiana MATVEEVA, [......], Anatoly OBZHIROV, Jeffrey POORT, Hirotsugu MINAMI, Hirotoshi Sakagami, Akihiro Hachikubo, Kinji Hyakutake, Hitoshi TOMARU, Masato Kida, Nobuo Takahashi, Hitoshi Shoji
  [show abstract] [hide abstract]
  ABSTRACT: Differences in seepage activity among three gas-seepage structures including hydrate-bearing sites at the Derugin Basin, NE Sakhalin Island, Russia were investigated. Chemical analyses of pore-water geochemistry, water-content distribution and stable isotopes were conducted to describe the complicated geochemical seepage environments involving a flux of free-gas and/or gas-saturated water. Traces of deep ascending fluid were not found in the hydrate-containing Hieroglyph seep, but were suggested in the lower parts of cores from the CHAOS and Kitami seeps based on the presence of abnormally heavy deuterium.
• Source

  Available from: Akihiro Hachikubo

  Article: Coexistence of structure I and II gas hydrates in Lake Baikal suggesting gas sources from microbial and thermogenic origin

  Masato Kida, Oleg Khlystov, Tamara Zemskaya, Nobuo Takahashi, Hirotsugu Minami, Hirotoshi Sakagami, Alexey Krylov, Akihiro Hachikubo, Satoshi Yamashita, Hitoshi Shoji, Jeffrey Poort, Lieven Naudts
  [show abstract] [hide abstract]
  ABSTRACT: 1] We report the field observation of hydrate deposits of different crystal structures in the same cores of a mud volcano in the Kukuy Canyon. We link those deposits to chemical fractionation during gas hydrate crystallization. Gas composition and crystallographic analyses of hydrate samples reveal involvement of two distinct gas source types in gas hydrate formation at present or in the past: microbial (methane) and thermogenic (methane and ethane) gas types. The clathrate structure II, observed for the first time in fresh water sediments, is believed to be formed by higher mixing of thermogenic gas. Citation: Kida, M., et al. (2006), Coexistence of structure I and II gas hydrates in Lake Baikal suggesting gas sources from microbial and thermogenic origin, Geophys. Res. Lett., 33, L24603, doi:10.1029/2006GL028296.
• Article: 陰イオン交換樹脂による亜鉛とカドミウムの分離, 定量亜鉛地金中のカドミウムの微量定量法

  力 松尾, 信夫 高橋, ツトム マツオ, ノブオ タカハシ, Tsutomu Matsuo, Nobuo Takahashi
  [show abstract] [hide abstract]
  ABSTRACT: Optimum conditions for the separation of cadmium from zinc by an anion exchanger (Dowex 1 -X8, 50-100mesh) were studied.　In the hydrochloric acid solutions ranging from 0.04 to 0.05 M, cadmium ions were completely taken up by the anion exchanger through the formation of [CdCl_4]~(2-), while zinc ions remained in the solution. Under these conditions, the separation of cadmium ions could be accomplished even at a molar ratio of zinc to cadmium of 2000 : 1. The adsorbed cadmium was eluted with deionized water and then titrimetrically determined with 1/1000 M EDTA solution. Thus, a minute quantity of cadmium in high purity zinc metals (>99.999%) can be determined by this procedure.