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論文
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Tazaki, Kazue ; Ishida, Hideki ; 田崎, 和江 ; 石田, 秀樹
概要:
金沢大学理工研究域地球社会基盤学系
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| 2.
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Tazaki, Kazue ; Zhou, Guoping ; Makaino, Koji ; 田崎, 和江 ; 周, 国平 ; 馬飼野, 光治
概要:
金沢大学理工研究域地球社会基盤学系<br />デイーゼルエンジン車の排気ガスを一日2回直接受けたスイセンを採取し, XRF, SEM-EDX, TEMで観察および分析を行った.排気ガスに汚染されたスイセンの葉は黒色に変色し,気孔の内部及び周
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辺には,Sを含む多量の微粒子が被覆し, Al, Si, Cl, Ca, K, Feの増加も認められた.これらの結果は,ディーゼルエンジンの排気ガスが植物の光合成などの生理作用に,短期間で大きく影響を及ぼすことを明らかにした.<br />Polluted narcissuses by exhaust emissions derived from a diesel engine twice a day were investigated by XRF, SEM-EDX and TEM analyses. Polluted narcissus was characterized by no flower, deformed leave and the change of color from green to yellow and black. S was increased about 6 times. About 33% of S-coated carbonaceous soots was retained through breath holes by narcissus, causing the normal breath and photosynthesis of narcissus damaged. This could be a major factor of narcissus growing abnormally during a short period (2 months).
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| 3.
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田崎, 和江 ; Tazaki, Kazue
概要:
金沢大学理工研究域地球社会基盤学系<br />地球上に広く分布する微細な炭素粒子は,環境の変化に最も敏感に対応する物質の一つである.その炭素の起源,微細形態,結晶成長の過程,化学結合,分布などを明かにし,炭素物質を評価するうえで,電子線を用
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いた手法が有効である.ここには,様々な炭素物質について,その目的に応じた有効な分析方法の実例を示した.走査型(SEM)および透過型電子顕微鏡(TEM)による観察は,炭素物質の微細形態,結晶成長過程,結晶度を知るのに適している.バクテリアなどを含む有機物が濃集した非晶質の炭素は,続成作用により,高結晶度のグラファイトヘと変化する.初期の炭素物質は,球粒,管,フレーク,薄膜,シート,リボン状などさまざまな形態をとり,最も成長した結晶であるグラファイトは,六角板状のバウムクーヘン状構造をとる.炭素の分布を知るには,エレクトロンマイクロプローブ(EPMA)やオージェ(Auger)による元素濃度分布図が有効である.オージェは,導電性物質の蒸着を必要としないので,岩石中のカーボンの存在を薄片の状態で検出することが可能である.高い導電性を持つことで知られているワイオミング産のSybille Monzosyeniteに,オージェ分析を適用し,鉱物境界に高濃度の炭素が存在することが,高導電性の要因の一つであることを明かにした.また,オージェは導電性物質の蒸着なしで,オングストロームのオーダの最表面分析が可能である.フーリエ赤外線分析(FT-IR)は,炭素の化学結合や水分子との結合状態を知ることができる.グラファイトは,その結晶度の違いによりOHやC-C結合の吸収の程度が異なる例として,片麻岩中の低結晶度の炭素から水分が抜け,次に酸素が抜けてグラファイトヘと変化するプロセスを示した.また,電子線走査化学分析器(ESCA)による炭素(1S)の高分解能分析は,様々な炭素結合の種類とその量比を知るのに有効である.この方法により,深海底堆積物中の海緑石に含まれる炭素が,COO,C-O,C-Cそしてグラファイトといった異なる炭素結合により構成されていることを明かにした.この結果は,海緑石が有機物起源であり,その後,無機化すること,有機炭素と無機炭素の境界は明瞭ではないことなどを示している.さらに,重イオン加速器(RILAC)は,炭素が表面吸着しているか,または結晶構造に組み込まれているかの判断に有効である.例えば都市ガスのすすの分析は,金属やSiO_2といった標準試料と比べ,炭素が結晶性の構造を待つことを示した.同時に,この方法は,酸素と水素の存在状態の差異も明瞭に表わすことができる.重イオン加速器は,大気からもたらされた汚染物質の炭素と物質本来の結晶構造中の炭素原子との区別に有効である.<br />Very fine carbon particulates formed by both inorganic and biological processes in the Earth have the most sensitive response to global change. Various electron microtechniques are usufu1 to reveal the micromorphology, texture, growing processes, crystalinity, chemical bond and the distribution of carbon materials. In this article useful methods for evaluation of carbon in various carbon materials are introduced. Amorphous organic carbon naturally and artificially transforms into high crystalline graphite. SEM and TEM observations reveal that precursor carbon materials are composed of spherules, tubular, fiakes, thin films ,fla tsheets, and ribbon texture. Bacteri aand nannobacteria may play a prorninent catalyzing role in the precipitatio onf carbon materia]s. Hexagonal onion-like texture is the most stable form ofcarbon durin ggraphitizatio n,EPMA and Auger can be used for carbon elernentary rnapping. Auger-spectrometer depth profiling and carbon content rnap applied to Sybille Monzosyenite having high electrical conductivity revealed a high concentration of carbon on grain boundaries of the minerals. Chemical bonding of carbon and hydrogen can be analyzed by FT-IR method. FT-IR spectra showing different intensity of OH and C-C absorbed bands are related with the degree of crystalinity of graphite in rocks. The result suggests that graphite occurred by dehydration and reduction of organic materials, ESCA is usufu1 method to know various carbon binding. High resolution of C_ls spectra of micro ESCA can discriminate various carbon chemical binding, such as COO, C-O, C-C, and graphite. ESCA spectra of glauconite in deep sea sediments showed various ratios of COO, C-O, C-C and graphite, suggesting organic origin of glauconite. The result also suggests that there are no clear boundary between organic and inorganic carbon. RILAC method can be used for evaluation of atmospheric contamination of carbon from structural carbon. RILAC spectra of soot showed characteristic recoiled carbon, oxygen and hydrogen ions with standards of purity for metalic plate and Si0_2.
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| 4.
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Tazaki, Kazue ; 田崎, 和江
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金沢大学理工研究域地球社会基盤学系<br />Because of increasing population, human activity has become a dominant process modifying the eart
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h environment. Understanding the new environmental stresses includes study of interface processes on macro- and micro-scales. Application of electron microscopy to the study of sulfides and sulfate complexes in atmospheric dust, in acidic river sediment, in sewage sludge and in water solution, provide unique information on the interaction between bacteria and human activities in close-to-environmental conditions. Microorganisms exhibit great powers of trace metal accumulation and immolization. They may be frequently encountered in extreme metal contaminated environment both natural and man-made. The sulfides leading to the formation of sulfide minerals were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) equipped with energy-dispersive X-ray analysis (EDX). For example: 1 Atmospheric sulfide minerals in air dust, 2 Sulfides precipitation with bacteria in polluted mining river sediment, 3 Sulfide mineralization in sludge, 4 Experimental sulfide mineralization in 9 K medium. Atmosphere oxidation rate of SO2 is largely balanced by exchange across the hydrosphere-biosphere-land surface interfaces. Fluctuating volcanic emissions or Chinese loess may have profound influence. SEM-EDX observation indicated that the air dust and acid rain-water contained gypsum, barite and sulfur films which may be due to contributions from volcanic eruption. TEM observation showed bacteria with S-rich thin films in dust of rain-water suggesting interaction between polluted S-rich precipitation and bacterial activity in atmospheric environment. The study of acidic river sediment indicates the enormous influence of the biosphere in maintaining river chemistry of sulfate complexes and sulfides. The electron microscopic techniques enable us to examine the reactive surface at the micron scale, the surface where reaction occurs, that control so many of the basic biogeochemical processes. Micro-scopic study showed that all biomass contains a significant quantity of metallic constituents, and mineralization in living and dead biodebris may contribute to sulfides transport from the hydrosphere into sediment. The bacterial cell walls are remarkable in their ability to fix metals and provide sites for nucleation and growth of Mn, Fe, Cu and Zn minerals. The sulfate complexes and sulfides in sludge in Lake Nakaumi were investigated, including study on the formation of minerals and uptake of metals by bacteria or plant. SEM-EDX observation showed that pyrite, pyrrhotite and gypsum were formed on the top of surface sludge. The aggregate of framboidal pyrite gradually grew in diatom shell which composed of S and Fe, suggesting the processes of sulfide mineral formations related with organisms. The sewage sludge is a valuable source of N, P, and heavy metallic elements (e. g. , Cu, Fe, Mn, Zn) and organic matter. Such metals are of environmental concern due to their potential effects on plant uptake and growth. Jarosite used in the laboratory study was produced from a mixture of 9 K medium and Thiobacillus ferroxidans for a period of several days. SEM-EDX observation with XRD showed that jarosite was formed after 3 days and ammoniojarosite was formed after 7 days from the experimental solution. If T. ferroxidans is present, jarosite can be formed at room temperature by aerating solutions of FeSO4, and K2SO4 at pH 2 within few days. Elemental sulfur interacted with the metal-loaded bacterial cells, affected both the eventual earth science and crystal habit of the metal sulfides, and formed a variety of crystalline metal sulfides. Observation of sulfate complexe changes is unique opportunity to better manage all our earth environment.
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| 5.
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Watanabe, Chihiro ; Monzen, Ryoichi ; Tazaki, Kazue
概要:
金沢大学大学院自然科学研究科機能創成システム<br />The effects of addition of Zr and Ag on the mechanical properties of a Cu-0.5 wt%Cr alloy ha
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ve been investigated. The addition of 0.15 wt%Zr enhances the strength and resistance to stress relaxation of the Cu-Cr alloy. The increase in strength is caused by both the decrease in inter-precipitate spacing of Cr precipitates and the precipitation of Cu5Zr phase. The stress relaxation resistance is improved by the preferentially forming Cu5Zr precipitates on dislocations, in addition to Cr precipitates on dislocations. The addition of 0.1 wt%Ag to the Cu-Cr and Cu-Cr-Zr alloys improves the strength, stress relaxation resistance and bend formability of these alloys. The increase in strength and stress relaxation resistance is ascribed to the decrease in inter-precipitate spacing of Cr precipitates and the suppression of recovery during aging, and to the Ag-atom-drag effect on dislocation motion. The better bend formability of the Ag-added alloys is explained in terms of the larger post-uniform elongation of the alloys. © 2007 Springer Science+Business Media, LLC.
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| 6.
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Watanabe, Chihiro ; Monzen, Ryoichi ; Tazaki, Kazue
概要:
金沢大学大学院自然科学研究科機能創成システム<br />The effects of addition of Zr and Ag on the mechanical properties of a Cu-0.5 wt%Cr alloy ha
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ve been investigated. The addition of 0.15 wt%Zr enhances the strength and resistance to stress relaxation of the Cu-Cr alloy. The increase in strength is caused by both the decrease in inter-precipitate spacing of Cr precipitates and the precipitation of Cu5Zr phase. The stress relaxation resistance is improved by the preferentially forming Cu5Zr precipitates on dislocations, in addition to Cr precipitates on dislocations. The addition of 0.1 wt%Ag to the Cu-Cr and Cu-Cr-Zr alloys improves the strength, stress relaxation resistance and bend formability of these alloys. The increase in strength and stress relaxation resistance is ascribed to the decrease in inter-precipitate spacing of Cr precipitates and the suppression of recovery during aging, and to the Ag-atom-drag effect on dislocation motion. The better bend formability of the Ag-added alloys is explained in terms of the larger post-uniform elongation of the alloys. © 2007 Springer Science+Business Media, LLC.
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| 7.
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Watanabe, Chihiro ; Nishijima, Fumiya ; Monzen, Ryoichi ; Tazaki, Kazue
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金沢大学大学院自然科学研究科機能創成システム<br />The effects of P and Cr addition and two-step aging on the microstructure and mechanical pro
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perties of a Cu-4wt%Ni-0.95wt%Si alloy have been examined. The addition of 0.02wt%P improves both strength and elongation because it suppresses discontinuous precipitation reaction. The Cr addition to the Cu-Ni-Si-P alloy decreases greatly the grain size, resulting in an increase in elongation. Two-step aging, pre-aging at 300 or 350°C and subsequent second-step aging at 450°C, causes an increase in strength without reducing elongation. The increase in strength is attributable to the decrease in inter-precipitate spacing by the two-step aging. The two-step aged Cu-4wt%Ni-0.95wt%Si-0.02wt%P-0.02wt%Cr alloy attains a tensile strength of 830MPa, an elongation of 13% and an electrical conductivity of 35%IACS.
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| 8.
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Tazaki, Kazue ; Asada, Ryuji
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金沢大学大学院自然科学研究科環境動態<br />Mercury is a toxic substance that is widely distributed throughout the hydrosphere, biosphere, a
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nd lithosphere. Mine waste environments and mine waters support a wide diversity of microbial life. The microbial ecology of environments where mine waters are polluted with heavy metals is poorly understood. Here, we describe the features of bacteria in mercury-contaminated gold panning ponds in a small-scale gold mine (Geita) near Lake Victoria, Tanzania using energy filtering transmission electron microscopy (EF-TEM) and scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy (STEM-EDX). Most bacteria in the panning pond showed thick exopolysaccharides (EPSs), and many clay minerals attached onto the surface of EPSs. The clay minerals and EPSs might act as protective layers for the bacteria against toxic materials. The clay minerals were composed of smectite, halloysite, and kaolinite associated with calcite and goethite. Scanning electron microscopy equipped with energy dispersive X-ray spectroscopy indicated that the bulk soil samples contained abundant Si, Al, K, Ca, and Fe with heavy metals such as Au, Ti, and Ag. The results indicate that Hg pollution from panning ponds is caused by not only volatilization of Hg from Au-Hg amalgams, but Hg is also released into the air as dust mixed with dry fine clays, suggesting high long-term environmental risks. Mercury-resistant bacteria associated with clay minerals may have a significant effect on the weathering processes of the ore during long-term bioremediation. The clay mineral complexes on the surface of bacterial cell walls are a stimulator for Hg-resistant bacterial growth in mud ponds contaminated with the Au-Hg materials. 全文公開200809
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| 9.
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Nonaka, Tsuguhiro ; Ismail, Nasir ; Tazaki, Kazue ; Mori, Tadahiro
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Determination of microbial corrosion is very important to anticipate the remaining service life of the concrete structur
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es in order to avoid the recurrence of structures collapse or failures. The behaviors of Fe-ions and formation of Fe-rich layer were studied. Fe-ions started to migrate to carbonated zone during carbonation process. When surface pH decreased by microbial corrosion process, Fe-ions accumulated and concentrated locally forming Fe-layer at areas between corroded and sound zones. Results show that Fe-layer depth is more than the depth of corrosion. Calculation of Fe-layer formation rates as a mean to determine the corrosion rate with certain factor of safety is proposed. コンクリートの微生物腐食を表す指標として, 腐食部分の先端に見られるFe層の存在理由とその意義を室内実験と現場調査により明示する. ICPでのFeイオンの分析から, 炭酸化と微生物腐食によるpHの低下によって, 腐食先端にFeイオンが集積することがわかった. この挙動は現場調査結果からも確かめられた. さらに腐食深さとFe層の位置には比例関係が見られた. 微生物腐食速度の決定にFe層の追跡が有効と考えられる.
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| 10.
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Tazaki, Kazue ; Morikawa, Toshikazu ; Watanabe, Hiroaki ; Asada, Ryuji ; Okuno, Masayuki
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出版者照会後に全文公開<br />Microbial formation, Bio-imogolite, Fibrous network structure, Bacterial cell wall, Cohesion, Electron microscope
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