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Memoirs of the Muroran Institute of Technology No. 70
Get PDFapplication/pdf個々の収録アイテム
http://hdl.handle.net/10258/00010383
http://hdl.handle.net/10258/00010382
http://hdl.handle.net/10258/00010381
http://hdl.handle.net/10258/00010380
http://hdl.handle.net/10258/00010379
http://hdl.handle.net/10258/00010378
http://hdl.handle.net/10258/00010377
http://hdl.handle.net/10258/00010376
http://hdl.handle.net/10258/00010375
http://hdl.handle.net/10258/00010374
http://hdl.handle.net/10258/00010373
http://hdl.handle.net/10258/00010372
http://hdl.handle.net/10258/00010371othe
Chiastic Structure of Kamuyyukar "A Prince of Japanese" Influenced by Two Japanese Stories
Get PDF本稿では、2種類の和人の物語（前半は「三人兄妹」であり後半は「甲賀三郎譚」の展開である）に由来する、白沢ナベを話者としたカムイユカラ「和人の若殿の物語」に注目し、交差対句に基づく構造分析をおこなった。本稿の分析によれば、テキスト全体を範囲とする交差対句と、テキストの部分における交差対句の、双方をみいだすことができた。このことは、テキストにみとめられる交差対句が、アイヌ口承に付加された「形式」自体の伝承によるものではなく、テキストが編成された際に新たに付加されたものであることを示している。なお、テキスト全体の交差対句は主に異郷訪問譚の性質に起因し、部分にみとめられる交差対句については話者の心性に起因している。journal articl
Microstructure and Properties of SUS304 Stainless Steel Joints Brazed with Electrodeposited Ni-Cr-P Alloy Coatings
Get PDFapplication/pdfIn this study, an amorphous Ni-13.4Cr-11.6P (mass%) alloy coating with a thickness of 30 mu m was deposited on the surface of SUS304 stainless steel as a brazing filler metal to conduct brazing. The differential thermal analysis measurements indicate that the electrodeposited Ni-13.4Cr-11.6P alloy has a melting point of approximately 892 degrees C, which is almost consistent with that of the commercial BNi-7 filler metal. The microstructure, shear strength, and fracture mode of the brazed joint were investigated using an electron probe X-ray microanalyzer, a scanning electron microscope, an optical microscope, and a universal testing machine. The results showed that the brazed filler metal is filled between the SUS304 stainless steel plates without any flaws in the brazed seam. The P-containing phases, i.e., the Cr-P rich phase and the (Ni,Fe)(3)P phase, were formed in the brazed seam. The shear strength of the brazed joint obtained in this study is 59.0 MPa. The fracture occurs in the brazed filler zone, where the brittle P-containing phases are present. Galvanic current measurement results showed that the brazed Ni-13.4Cr-11.6P alloy coating has a better corrosion resistance than that of the brazed Ni-11P alloy coating, which can be attributed to the formation of a large amount of Ni-Fe solid solution and Cr-P rich phase in the top layer of the brazed Ni-13.4Cr-11.6P alloy coating.journal articl
表面プラズモン顕微鏡法による異方性媒質の特性評価
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf本研究では，光学的異方性を有する薄膜試料の顕微分析を可能とするナノプローブの開発を行い，これを用いて10-3 ~ 10-1 の範囲で複屈折を測定することに成功した. 開発したプローブでは集束表面プラズモン（高開口数の顕微鏡対物レンズを用いて集束させた光で励起した表面プラズモン）を利用しており，集束表面プラズモンの空間周波数応答から複屈折の測定を行う．具体的には，試料の複屈折によって，反射光空間周波数分布に生じる楕円状の光吸収パターンの方位と楕円率から，複屈折の大きさと光学軸の方位を求める．このプローブは，従来法に比べ極めて微小な領域における試料の複屈折を測定することができる．はじめに，この手法の妥当性を検証するため，光誘起複屈折を示す薄膜異方性試料の複屈折の大きさと進相軸の方位を，さまざまな条件下で測定した．実験では，アゾ系高分子（PAZO: poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene-sulfonamide]-1,2- ethanediyl sodium salt]）スピンコート薄膜を作製し，紫外光照射が引き起こすシス型からトランス型への遷移がもたらす複屈折を調べた．その結果，0.01 ~ 0.07の範囲で変化することを測定することができた．また，さまざまな偏向状態の紫外光を照射したときに，反射光の空間周波数分布に生じる楕円状の光吸収パターンの回転から，進相軸の方位の変化を確認することができた. また，大きな複屈折を示す試料の測定におけるプローブの適用性を確認するために，巨大複屈折を示すアゾ系高分子を合成し，これを薄膜化した試料の複屈折を測定し，その結果と従来からの偏光解析手法による測定結果との相関を確認した．さらに，開発したプローブを生体試料の微小複屈折測定に応用する検討を行った．ここでは，ニワトリの表皮や真皮など皮膚のさまざまな部位の複屈折測定を行い，表皮では ~ 0.008 ，真皮では ~ 0.03 の複屈折を示すことを確認した．また，この測定から，皮膚組織がもたらす強い光散乱も無視できることを確認できた．これによって，無標識でさまざまな病理診断が行える潜在性を示すことができ，たとえば，紫外光環境下での繊維芽細胞の複屈折を測定することで，皮膚日射病を診断できると考える．In this thesis, I have developed a nano-probe for the microscopic characterization of anisotropic samples specially in the form of thin films. The developed probe has been successfully tested to measure birefringence in the range of 10-3 ~ 10-1. The probe was developed with focused surface plasmon (interference of surface plasmons generated by coupling with convergent incident light from a high numerical aperture microscope objective). The birefringence of the sample caused the change in the propagation constant along the principal directions of the sample. Elliptical absorption pattern in the reflected spatial frequency distribution was observed on introduction of anisotropic sample as Kretschmann configuration. The ratio of the propagation constants along the principal directions yields the magnitude of birefringence while the orientation of the elliptical absorption pattern in the reflected spatial distribution denotes the fast axis of the sample. The developed probe is thus able to quantitatively characterize anisotropicity of samples in microscopic region. The detailed characteristics of the anisotropic samples in the form of thin films exhibiting photo-induced birefringence have been analyzed in terms of the magnitude of birefringence and the direction of fast axis. I examined azo-polymer PAZO poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzene-sulfonamide]-1,2-ethanediyl sodium salt] thin films produced by spin coating. The birefringence varies in the range of 0.01 - 0.07 with low density under the influence of ultra-violet radiation due to photo-isomerization (transition from the cis-state to the trans-state). The fast axis of the sample could be rotated with the change in polarization of the ultra-violet light. This could be further correlated with the change in orientation of elliptical absorption pattern at the reflected spatial frequency distribution. Further, to perform high birefringence measurement with the developed probe, I also synthesized gigantic birefringence azo-polymer (exhibiting photo-induced birefringence: Δn ∼ 0.4). I correlated the results with simple in-line polarimetric set-up. Also, I checked the applicability of the developed probe for determining very low birefringence of bio-samples. I analyzed various parts of the chicken skin samples like the epidermal and the dermal layers to observe the birefringence changes. It was found that the dermal layer of the skin showed Δn ∼ 0.03 while that of the epidermis showed Δn ∼ 0.008. Further I confirmed that the effect of scattering on near-field anisotropic characterization is negligible. Thus, this method can be used to characterize highly scattering samples like skin. I believe that the developed probe can find potential application towards disease detection, as most tissues within human body secrete collagen (possessing intrinsic birefringence). The increase of birefringence in such tissues can be used as a label free bio-marker. Potential example include detection of dermatoheliosis from the change in the quantitative birefringence of the fibroblasts in the ultra-violet environment.当アイテムは要旨のみの公開になっています（2021-12-9）thesi
Did de Saussure find 'de Saussure’s law'?
Get PDF本稿は，リトアニア語のアクセント移動規則である，「ソシュールの法則」のプライオリティーについて論じている．ソシュールは1896年に論文「リトアニア語のアクセント法」の中でこの法則を発表した．それ以来この法則は「ソシュールの法則」と呼ばれている．しかしA.レスキーンは1880年代にライプチッヒ大学の講義でこの法則を学生に教えていた．レスキーン門下の研究者らの著作にはこの法則を使ったものがあり，この法則のプライオリティーが問題になる．journal articl
Sakurai-Sugiura法を用いた光ファイバの分散特性の高速高精度解析に関する研究
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf光ファイバの断面構造設計には，自動最適化技術が不可欠である．構造最適化は，目的関数を最小化する構造変数の組み合わせを自動で探索することで実施する．構造探索時に目的関数を多数回計算するため，目的関数の算出に用いる分散特性の計算が高速でなければ，実用的な時間で最適化することが困難となる．例えば，群速度ならびに群速度分散であれば，電磁界解析により得られた伝搬定数を波長に関して 1 階微分， 2 階微分することで求まる．伝搬定数算出には，有限差分法や有限要素法に基づく市販の電磁界シミュレータが利用できる．通常は，百万程 度の自由度を有する一般化固有値問題に帰着させる有限要素解析(FEA)を行う．この求めた伝搬定数の微分値は，数値微分である差分法，固有値問題から導いた超越方程式を陰関数定理に基づき微分する方法で算出する．差分法は，複数の波長における位相速度値から多項式補間により微分値を計算するものであり，容易に計算できる．しかしながら，適切な差分間隔が，求める微分値よりも高次の微分値から定まるため，多数の位相速度計算値を用いて差分間隔を決定する必要がある．他方，陰関数定理に基づく方法では，行列式の微分を用いると計算時間が長くなり，左固有ベクトルを用いて超越方程式を導出すると 2 階微分に固有ベクトルの微分が必要となる．このように伝搬定数の微分値計算には，未だ課題が残されていた．一方，Trefftz法を電磁界解析に適用したMultipole Method(MM) は，波動関数を補間関数とするため高精度の位相速度値が求まることが期待でき，同程度の精度のFEAと比較すると，固有値問題の係数行列の次元が小さくなるため，Sakurai Sugiura法 (SSM) により高速に計算可能である．しかしながら，波動関数展開の展開次数を大きくすると電磁界解析精度が低下する問題があった．またSSMに起因するスプリアス解を含んだ位相定数が求まるので，スプリアス解を判別除去する必要がある．さらに MM では，円柱ならびに楕円柱を含む断面構造しか扱えなかった．本論文は，光ファイバの自動最適化設計を目的として，SSMを用いた光ファイバの高速高精度な分散特性解析法について取り纏めたものである．まず伝搬定数の微分値計算法として，SSMにより得た4行4列以下の一般化固有値問題から4次以下の代数方程式を導き，固有値を周波数に関する陽関数として表現し，自動微分を適用することで微分値を得る方法を開発した．またMMの問題点を解消するために，定式化を変更し，波動関数展開の展開次数の増加に伴う精度低下の軽減に成功した．さらにSSMの解に含まれるスプリアス解は，低計算コストである固有値の条件数により，判別除去できることを示した．従来のTrefftz法に課されていた形状の制約を取り除くため，ハイブリッドトレフツ有限要素法にSSMを適用する伝搬特性解析法を開発した．これらの妥当性と有用性は，円や楕円空孔，環状型空孔を有するホーリーファイバの数値解析例により示した．For optimizing profiles of optical fibers by solving an optimization problem with an objective function including propagation constants, group velocities, or group velocity dispersions, fast and precise numerical methods are required for computing these propagation characteristics. Trefftz methods including the transfer matrix method and the multipole method for computing propagation constants are attractive for designing simple profile of optical fibers due to the advantage of being inherent mesh-free nature and easy imposing the radiation-condition on the guided electromagnetic fields without artificial medium surrounding the cladding over the finite-element method and finite-difference time-domain method. However, four improvements of the Trefftz method were required: (1) there is no fast and precise scheme for computing the differential coefficients of degenerate and nondegenerate propagation constants computed by the Trefftz methods, (2) upper and lower limits of the Fourier-Bessel expansions for the wavefunctions employed in the Trefftz methods may be small for accurately approximating the fields in the complex profile, (3) the Trefftz methods employ the wave-functions for approximating electromagnetic wave fields cannot apply to complex profiles with inhomogeneous media, and (4) because the Sakurai-Sugiura method (SSM) inherently includes spurious solutions of the nonlinear eigenvalue-problem, the low coast criteria in computation for sorting the eigenvalues from results by the SS method was not known . This thesis presented solutions for overcoming above problems of Trefftz method analysis with the SSM solver as follows: (1) a fast and precise scheme to compute the differential coefficients of propagation constants for computing group velocities and group velocity dispersions by making up the explicit forms of eigenvalues from a generalized eigenvalue problem converted from a nonlinear eigenvalue problem given by the Trefftz methods employing the SSM, (2) a refined formulation of the multipole method for relaxing the upper and lower limitations of the number of Fourier-Bessel expansions of electromagnetic fields in optical fibers, (3) a solution based on the hybrid Trefftz finite element method employing the SSM as a nonlinear eigenvalue solver for analyzing complex profiles of photonic optical fibers, and (4) a criterion for selecting the spurious solutions from the eigenvalues computed by the SSM. Numerical results of step-index and holey fibers with circular, elliptic, and ring-shaped cylinders showed that developed solutions remove the problems of the Trefftz methods.doctoral thesi
不斉マイケル付加反応に用いる糖型 γ-アミノ有機分子触媒の開発
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf医薬品を含む多くの生物活性化合物は光学活性物質であり, その鏡像異性体は異なる生体内活性を示すことが多いため, 有効な一方の鏡像異性体を高立体選択的に合成するための不斉合成反応，特に不斉触媒を用いる触媒的不斉合成反応の開発は創薬分野や様々な光学活性機能性分子を創製するために重要である.その不斉触媒の中で，金属を含有しない有機分子触媒は空気中で安定であり取り扱いやすく安価であるという利点などを有するため, 次世代の環境調和型触媒として現在活発な研究開発が行なわれている.著者は, 新規多点認識型有機分子触媒としてこれまでその機能性の検討がなされていなかった糖型γ—アミノアアルコールとγ—アミノエーテルに着目し，その不斉触媒としての機能解明を不斉マイケル付加反応に適用することにより試みた. 適用する不斉マイケル付加反応は炭素—炭素結合形成反応として，さらに四級不斉中心の構築にも有用であることから各種医薬品や複雑な生物活性化合物を合成するための鍵反応として汎用されている。新規有機分子触媒として糖型γ—アミノアアルコールおよびγ—アミノエーテル有機分子触媒を容易に入手可能なキシロースから数工程を経て創製し, γ—アミノアアルコールおよびγ—アミノエーテル触媒の不斉触媒活性をß-ケトエステル類とニトロスチレン類との不斉マイケル付加反応に適用し検討した．その結果として, γ—アミノアアルコールおよびγ—アミノエーテル触媒が本反応において不斉触媒活性を示し，優れた化学収率と良好な光学収率で光学活性マイケル付加生成物を与えることを見出した. 得られた生成物は，創薬のための様々な生物活性化合物の合成中間体として有用であり，この合成中間体から新薬候補化合物を創製できることが期待される．本研究において著者は，「その分子中に基質との共有結合部位と水素結合部位，さらには反応のエナンチオ選択性の制御に有効な糖構造部位を併せもつ新規多点認識機能を発現する糖型γ—アミノアルコールおよびγ—アミノエーテル有機分子触媒」を開発することに成功し, それらが創薬に有効な不斉マイケル付加反応において良好な不斉触媒活性を示すことを明らかにした. 開発した本糖型触媒は，他の有用な不斉触媒反応においても触媒機能を示すことが期待され，さらに，本反応によって得られる化合物は様々な医薬品をはじめとする生物活性化合物の合成中間体として有用であることから，本研究の成果は, 新薬創製を指向した合成開発研究に大きく貢献できると期待される.A lot of biologically active compounds, including drugs, are optically active and often only one of the enantiomer shows a high biologically activity. Therefore, it is important to develop a synthetic methodology for providing only necessary enantiomer. As the methodology, catalytic asymmetric synthesis, in which the use of a low amount of a chiral catalyst theoretically enables infinite production of optically active compounds, is the most efficient in the synthetic organic chemistry field. Moreover, this methodology is also important in terms of energy saving and environmental friendliness. The chiral catalysts used in catalytic asymmetric syntheses can be divided into two categories of organometallic catalyst and metal-free organocatalyst. Particularly, organocatalyst is stable in air, nontoxic, easy to handle, and inexpensive, so they are being focused on as next-generation, environmentally friendly catalysts. Author focused γ-amino alcohol as an organocatalyst. In contrast to β-amino alcohol as an organocatalyst, the utility of γ-amino alcohol was not much explored even though it is expected to have a high potential functionality as an organocatalyst similar to β-amino alcohol. As a compound, author selected a sugar based γ-amino alcohol and its derivative fixing 1,2-O-isopropylidene-D-xylofuranose structure as a backbone. This catalyst is expected to work as multipoint recognition catalyst having basic site, covalent and non-covalent hydrogen bonding sites in the single molecule. Proposed γ-amino alcohol contains an amino group acting as basic or covalent site and hydroxyl group acting as a non-covalent hydrogen bonding site and also sugar backbone acting as steric influence site for controlling stereoselective reaction course. Furthermore, this γ-amino alcohol can be easily prepared from commercially available D-xylose by few steps. As a reaction for providing the utility of the γ-amino alcohol, asymmetric Michael addition of β-keto esters with nitroolefins was selected. The Michael adducts from this reaction contain both quaternary and tertiary chiral carbon centers in the structure and the adducts work as an important synthetic precursor of the synthesis of many biologically active compounds including pharmaceuticals such as platencin (antibiotic). Author tried this reaction of β-keto esters with nitroolefins using sugar based γ-amino alcohol and γ-amino silyl ether organocatalysts at first time. As a result, the both catalysts were showed good catalytic activity in this reaction and the desired chiral Michael adducts was obtained in good chemical yields, diastereoselectivities and enantioselectivities. In this study, author revealed that the new explored sugar type γ-amino organocatalyst showed satisfactory catalytic activities in the Michael addition. It is expected that these results should be able to greatly contribute the development of new drug and its related compounds.doctoral thesi
不斉ヘテロ ディールス・アルダー反応に用いる新規有機分子触媒複合系の開発
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf医薬品をはじめとする多くの生物活性化合物は光学活性物質であり, その鏡像異性体は薬と毒のような，互いに異なる生体内作用を示すことが多い。そのため，有効な一方の鏡像異性体を高立体選択的に合成するための不斉合成反応の開発，特に不斉触媒を用いる触媒的不斉合成反応の開発は，新薬やキラル機能性分子を創製するために重要である。その不斉触媒の中で，金属を含有しない有機分子触媒は毒性が無く，空気中で安定であり取り扱いやすく安価であるなどの利点を有するため, 次世代の環境調和型触媒として現在活発な研究開発が行なわれている. 光学活性スピロインダノール類は，抗がん，抗 HIVや抗マラリヤ活性などの多彩な生物活性を示すことから，現在そのスピロインダノール骨格を構築するための有機合成反応の開発が活発に行われている。著者は，その合成反応として触媒的不斉ヘテロ ディールス・アルダー反応に着目し，その反応に有効な有機分子触媒複合系を開発することを目的として本研究を行った。著者は，有機分子触媒複合系として，β—アミノアルコールおよびβ—アミノシリルエーテルをそれぞれ触媒とし，アミノ酸を助触媒とするイサチン類とエノン類との不斉ヘテロ ディールス・アルダー反応を検討した。その結果，触媒としてはその分子中に第１級アミノ基や第１級水酸基，またシロキシ基をもつシンプルなキラルβ—アミノアルコールまたおよびβ—アミノシリルエーテルが，また助触媒としてはアミノ基に保護基したα—アミノ酸が本反応中で複合的に触媒活性機能を発現し，優れた化学収率とジアステレオ選択性およびエナンチオ選択性で目的のキラルイサチン誘導体が得られることが明らかとなった。本研究において著者は，光学活性スピロインダノール類の合成に有効な不斉ヘテロ ディールス・アルダー反応に用いる新規有機分子触媒複合系を開発することに成功した。開発した本触媒系は，他の創薬のために有用な不斉触媒反応においても触媒機能を示すことが期待され，さらに，本反応によって得られる光学活性スピロインダノール類は抗がん作用や他の様々な生物活性化合物の合成中間体としても有用であることから，本研究の成果は, 新薬創製を指向した合成開発研究に大きく貢献できると期待される.Many biologically active compounds, including pharmaceuticals, are optically active and often only one of the enantiomer shows a high biologically activity. Therefore, it is important to develop the synthetic methodology for providing only necessary enantiomer. As the methodology, catalytic asymmetric synthesis, in which the use of a low amount of a chiral catalyst theoretically enables infinite production of optically active compounds, is the most efficient in the synthetic organic chemistry field. Moreover, this methodology is also important in terms of energy saving and environmental friendliness. The chiral catalysts used in catalytic asymmetric syntheses can be divided into two categories of organometallic catalyst and metal-free organocatalyst. Particularly, organocatalyst is stable in air, nontoxic, easy to handle, and inexpensive, so they are being focused on as next-generation, environmentally friendly catalysts. Spirooxindoles are considered to be promising scaffolds in drug discovery. The structure of spirooxindoles is contained in many compounds having pharmacological activities such as contraceptive, anti-HIV, anticancer, antituberculosis, antimalarial, and antiproliferative drugs. Therefore, the development of an effective strategy for the preparation of highly optically pure spirooxindoles is a significantly challenging task in research. The hetero Diels–Alder (HDA) reaction is a versatile tool for effectively forming heterocyclic compounds. Especially, the catalytic asymmetric version of this reaction is the most efficient and convenient method for constructing a chiral heterocyclic skeleton, which acts as a precursor for many biologically active compounds and drugs. In this class of HDA reactions, the reaction of isatins with enones is one of the superior organic transformations for providing unique chiral spirooxindoles containing quaternary chiral carbon center on the structure. Author tried to explore new catalysts component system for this reaction using isatins as diene and enones as dienophile. As a result, author developed simple two catalysts component system consisting of primary β-amino alcohol or γ-amino silyl ether as catalysts and N-protected amino acid as a co-catalyst for the asymmetric HDA reaction of isatins with enones for the first time. These dual component systems showed efficient catalytic activities to afford the chiral spirooxindoles that are efficient synthetic intermediates for many biologically active compounds and drug discovery, in good to excellent chemical yields and with enough stereoselectivities. In this study, author revealed that the new explored catalysts component system showed excellent catalytic activity to the asymmetric HDA reaction of isatins with enones. It is expected that this results should be able to greatly contribute the development of new drugs and its related compounds.doctoral thesi
Two-Stage Polyhydroxyalkanoates (PHA) Production from Cheese Whey Using Acetobacter pasteurianus C1 and Bacillus sp. CYR1
Get PDFapplication/pdfCheese whey (CW) can be an excellent carbon source for polyhydroxyalkanoates (PHA)-producing bacteria. Most studies have used CW, which contains high amounts of lactose, however, there are no reports using raw CW, which has a relatively low amount of lactose. Therefore, in the present study, PHA production was evaluated in a two-stage process using the CW that contains low amounts of lactose. In first stage, the carbon source existing in CW was converted into acetic acid using the bacteria, Acetobacter pasteurianus C1, which was isolated from food waste. In the second stage, acetic acid produced in the first stage was converted into PHA using the bacteria, Bacillus sp. CYR-1. Under the condition of without the pretreatment of CW, acetic acid produced from CW was diluted at different folds and used for the production of PHA. Strain CYR-1 incubated with 10-fold diluted CW containing 5.7 g/L of acetic acid showed the higher PHA production (240.6 mg/L), whereas strain CYR-1 incubated with four-fold diluted CW containing 12.3 g/L of acetic acid showed 126 mg/L of PHA. After removing the excess protein present in CW, PHA production was further enhanced by 3.26 times (411 mg/L) at a four-fold dilution containing 11.3 g/L of acetic acid. Based on Fourier transform infrared spectroscopy (FT-IR), and H-1 and C-13 nuclear magnetic resonance (NMR) analyses, it was confirmed that the PHA produced from the two-stage process is poly-beta-hydroxybutyrate (PHB). All bands appearing in the FT-IR spectrum and the chemical shifts of NMR nearly matched with those of standard PHB. Based on these studies, we concluded that a two-stage process using Acetobacter pasteurianus C1 and Bacillus sp. CYR-1 would be applicable for the production of PHB using CW containing a low amount of lactose.journal articl
Evaluation of photocatalysis of Au supported ZnO prepared by the spray pyrolysis method
No full textapplication/pdfEnvironmental pollution by organic dyes used in industry is a serious problem in developing countries. Environmentally friendly treatment methods are being studied because conventional methods require chemical or additional decomposition treatment. In particular, oxidation via a photocatalyst is a promising alternative due to its chemical and physical stabilities and low cost. However, electron-hole recombination limits the photocatalytic activity in semiconductor photocatalysts such as ZnO and TiO2. This study investigates control of electron-hole recombination of the photocatalyst by loading Au on ZnO (Au/ZnO). Using the Ultrasonic Spray Pyrolysis (USP) method, Au/ZnO particle generation is easily achieved under various conditions. XRD analysis confirms the crystal peaks of ZnO and Au. The EDX mapping and STEM images of the particles show that the Au crystals are well dispersed in the inner and outer portions of ZnO. The photocatalytic decomposition rate of organic dye (Rhodamine-B) is faster than that of ZnO in all Au/ZnO particles, and the best photocatalytic activity occurs in particles with 0.1 mass% Au supported on ZnO particles. In addition, optimal photolysis activity occurs in 100 mL of 5 mg/L RhB aqueous solution and 10 mg dose of Au/ZnO particles. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.journal articl