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Gunputh, Urvashi Fowdar. "Antibacterial properties of TiO2 nanotubes coated with nano-ZnO and nano-Ag." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/11155.
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TiO2 nanotubes grown on titanium alloy are known to increase the biocompatibility of the alloy when used in dental/orthopaedic implants. Furthermore, their nanotubular structures can act as antibacterial agent carrier and as a scaffold for tissue engineering with the aim of adding antibacterial properties to the implant. This study aims at fabricating an antibacterial and biocompatible nanocomposite coating on Ti-6Al-4V involving nano-ZnO and nano-Ag. Initially, TiO2 nanotubes were self-assembled on the polished surface of medical grade Ti-6Al-4V alloy discs using anodisation. First silver nanoparticles were chemically reduced from silver ammonia using delta-δ-gluconolactone for different duration on the nanotubes to form TiO2-Ag composite coating. Nano HA was added to the latter coating with the aim of reducing toxicity from silver, hence forming TiO2-Ag-HA coating. Secondly, nano-ZnO was thermo-chemically grown on the TiO2 nanotubes using zinc nitrate and hexamethylenetetramine. They were then annealed at 350-550 oC hence forming TiO2-ZnO. HA was grown on the latter coating by a biomimetic method whereby the coated discs were placed in a concentrated simulated body fluid at 37 oC forming TiO2-ZnO-HA. The stability of the 4 coatings, TiO2-Ag, TiO2-Ag-HA, TiO2-ZnO and TiO2-ZnO-HA were assessed using the dialysis method (n=3 each) and then exposed to S.aureus for 24 hours in BHI broth. Their antibacterial properties were assessed using different assays and microscopic imaging with respect to different controls (n=6 each for assays and n=3 for imaging). Their biocompatibility properties were assessed in the presence of primary human osteoblast cells in DMEM media with the help of biochemical assays, molecular gene expression and microscopic imaging (n=3). Both silver and zinc coated nanotubes showed significant level of antibacterial properties with silver coating being more bactericidal than the coating containing zinc. Nonetheless, the zinc oxide coatings were more biocompatible than the silver coating. Nano silver and zinc oxide containing composite coatings were successfully synthesised and tested in the presence of bacteria and human cells. The final conclusion was that nano-silver was still toxic and nano-ZnO coatings were more biocompatible.
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Bachmann, Andreas R. "Gestufte Cu-Oberflächen und Ag-Nano-Streifen atomare und elektronische Struktur /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=970380801.
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Zhang, Shuai. "Development and evaluation of Ag-PTFE based nano-composite coatings for medical devices." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/763804f7-52f4-4fae-bed7-3c58e21e24ad.
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Wesner, Daniel [Verfasser]. "Nano-Bio-Technologie : Nanopartikel, zelluläre Strukturen und Bindungsreaktionen / Daniel Wesner. Fakultät für Physik - AG Biophysik und angewandte Nanowissenschaften." Bielefeld : Universitätsbibliothek Bielefeld, Hochschulschriften, 2012. http://d-nb.info/1022747436/34.
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Veron, Olivier. "Etude des mécanismes de coloration de verres obtenue par échange ionique Ag+/Na+ et précipitation de nano agrégats métalliques." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00617160.
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L'objectif est d'étudier par la méthode d'échange ionique à l'argent de verres silicatés la coloration induite etla réalisation de guides d'ondes planaires. Deux méthodes de modélisation de l'échange ionique sont présentées pour évaluer les paramètres de l'échange qui sont le coefficient de diffusion, la forme du profil et la mobilité des ions. Cette technique purement thermique permet la réalisation de guides d'onde à gradient d'indice, l'ajout d'un champ électrique permet d'obtenir un profil à saut d'indice. Différentes compositions de verre sont étudiées dans le but de déterminer la variation d'indice induite par la polarisabilité de l'ion argent plus forte que les ions sodium ou lithium initialement présents dans les verres. A la suite de l'échange ionique, un recuit peut être effectué dans le but de précipiter l'argent en nanoparticules métalliques qui possèdent des propriétés d'absorption intéressantes permettant de colorer les verres : la résonance plasmon de surface (RPS). Le mécanisme de formation de ces nanoparticules dépend de la température et de l'effet redox de l'environnement. L'irradiation effectuée par un laser pulsé nanoseconde des verres échangés permet la précipitation locale des nanoagrégats d'argent à la surface des verres. L'irradiation pulsée en régime femtoseconde permet une interaction dans le volume du verre, soit avec des nanoparticules déjà présentes dans le but de modifier la couleur localement, soit avec des verres échangés dans lequel des défauts sont générés pour ensuite favoriser la formation de nanoparticules par recuit. La modélisation de la résonance plasmon de surface effectuée permet d'évaluer le mécanisme de croissance des nanoparticules dans les verres. Les méthodes de caractérisation utilisées sont la microscopie électronique à balayage, la microscopie électronique en transmission, la spectrophotométrie UV/Visible, la photoluminescence et la spectroscopie infrarouge à transformée de Fourier.
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Viefhues, Martina [Verfasser]. "Analysis and preparation of (bio)nanoobjects in nano-microfluidic devices / Martina Viefhues. Fakultät für Physik - AG Biophysik und angewandte Nanowissenschaften." Bielefeld : Universitätsbibliothek Bielefeld, Hochschulschriften, 2013. http://d-nb.info/1029760381/34.
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Medrano, Sandonas Leonardo Rafael. "Influencia del desorden sobre la estructura atómica y las propiedades electrónicas de nano-partículas mono-metálicas de Cu y Ag." Master's thesis, Universidad Nacional Mayor de San Marcos, 2012. https://hdl.handle.net/20.500.12672/12342.
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Estudia la influencia del desorden químico y estructural sobre la estructura atómica y las propiedades electrónicas de un conjunto de nano-partículas mono-metálicas de plata y cobre con un número de átomos constituyentes especiales (números mágicos icosaedrales) que varía de 13 a 5083 átomos. Las nano-partículas son formadas mediante simulaciones de dinámica molecular usando un potencial de Johnson, basado en el método del átomo incrustado, para el cobre y un potencial tight-hinding para la plata. Además, se estudia el efecto del desorden químico en las nano-partículas haciendo variar la energía de sitio del Hamiltoniano electrónico tipo tight-hinding según una distribución uniforme. El desorden estructural fue producido aumentando la velocidad del enfriamiento durante el proceso de formación de la nano-partícula.Tesis
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Cuba, Supanta Gustavo. "Influencia de la velocidad de enfriamiento sobre las propiedades estructurales y electrónicas de nano-hilos mono-metálicos de Ag y Cu." Master's thesis, Universidad Nacional Mayor de San Marcos, 2014. https://hdl.handle.net/20.500.12672/5786.
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Estudia la influencia de la velocidad de enfriamiento (cooling rate o freezing) sobre las propiedades estructurales y electrónicas de nano-hilos mono-metálicos de plata y cobre constituidos con un número desde 200 hasta 5880 átomos correspondientes a diámetros de 0.49 a 2.86 nm para la plata y de 0.43 a 2.53 nm para el cobre y una longitud de 16.34 y 14.46 nm respectivamente.Tesis
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Acharya, Danda Pani. "Atomic Manipulation and Tunneling Spectroscopy on Metal and Semiconductor Surfaces." View abstract, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3292889.
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Khodja, Walid. "Organisation de nano-matériaux inorganiques au sein de matrices supramoléculaires poreuses recyclables." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30016.
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L'inclusion de nanoparticules métalliques dans des réseaux supramoléculaires poreux a connu un essor très important au cours des dernières années. En effet ces matériaux hybrides combinent les propriétés liées aux réseaux supramoléculaires poreux, telles qu'une importante surface spécifique et une grande modulation chimique des pores, et celles qui sont intrinsèques aux nanoparticules métalliques, comme les propriétés catalytiques ou optiques. De ce fait, ces matériaux composites sont explorés dans les domaines de la catalyse ou de la détection. Les réseaux supramoléculaires poreux regroupent trois grandes familles de structures bien distinctes, selon les interactions qu'elles mettent en œuvre pour maintenir leur intégrité structurale. Nous distinguons en premier les réseaux construits par des liaisons de coordination, appelés MOF (" Metal Organic Framework "). Ces réseaux poreux ont été largement étudiés pour l'incorporation de nanoparticules métalliques avec diverses fonctionnalités à la clé. Les réseaux supramoléculaires obtenus par associations covalentes, nommés COF (" Covalent Organic Framework "), ont été relativement peu exploités pour la croissance in situ de nanoparticules métalliques. Enfin, les architectures supramoléculaires poreuses dont la cohésion structurale est assurée par des interactions faibles telles que la liaison Hydrogène, et qui sont connus sous le sigle HOF (" Hydrogen-bonded Open Framework "), n'ont, à notre connaissance, jamais été mis en œuvre comme support de croissance de nanoparticules métalliques. L'objectif de cette thèse a été donc d'explorer la possibilité d'utiliser les architectures supramoléculaires poreuses fondées sur la liaison Hydrogène, comme matrices pour la croissance contrôlée de nanoparticules de métaux nobles. La première partie de la thèse fut consacrée à l'élaboration de cristaux de dimensions sub-micrométriques d'une architecture poreuse supramoléculaire, développée dans l'équipe et connue sous le pseudonyme SPA-2 (" Supramoléculaire Porous Architecture "), grâce à des conditions opératoires solvo-thermales. Deux raisons ont motivé notre choix pour cette matrice : sa porosité (estimée à 53 %), ainsi que ses canaux décorés par des fonctions pyridyls. La deuxième partie de ces travaux de recherche a conduit à l'obtention du matériau hybride Au@SPA-2. La synthèse de ce matériau procède par une fonctionnalisation des nanocristaux de SPA-2 par des thiocyanates, suivie d'une imprégnation, puis d'une photo-réduction du précurseur moléculaire d'or photosensible (Me2SAuCl). La post-fonctionnalisation du SPA-2 permet une imprégnation efficace en or (5 à 10 % de la masse totale). L'exposition au rayonnement ultraviolet du matériau [Au-SCN]@SPA-2 permet de réduire le complexe d'or, puis de générer des nanoparticules. Pour notre système hybride, il est possible de contrôler la taille des nanoparticules d'or (de 1 à 25 nm) par la durée d'irradiation. Il s'agit de la première synthèse de nanoparticules métalliques au sein d'une matrice supramoléculaire poreuse fondée sur l'interaction Hydrogène, jamais rapportée à ce jour dans la littérature. La troisième partie des travaux a été centrée sur la synthèse du matériau hybride Ag@SPA-2, avec la même stratégie qui a été mise en œuvre pour l'or, à savoir le piégeage d'un précurseur d'argent photosensible (AgNO3) par un anion, ici un chlorure, localisé dans les canaux du SPA-2. Des nanoparticules d'argent sont obtenues dans les canaux de SPA-2 par photo-réduction, sous UV, du matériau AgCl@SPA-2. Les caractérisations de ce matériau hybride mettent en évidence des nanoparticules d'argent distribuées uniformément au sein des nanocristaux octaédriques de SPA-2. La matrice SPA-2 est recyclable. Par simple dissolution dans une eau légèrement acide, il est possible d'isoler les nanoparticules de métaux nobles des briques constitutives du réseau poreux SPA-2. À partir de la solution aqueuse, la matrice SPA-2 initiale est régénérée par cristallisationThe interest for imbedding metallic nanoparticles in porous supramolecular networks has grown considerably in recent years. Indeed, these hybrid materials combine the properties related to porous supramolecular networks, such as a controlled porosity, large specific surface area, versatile chemical modulation; and those that are intrinsic to metal nanoparticles, such as catalytic or optical properties. As a result, these composite materials are explored in the fields of catalysis or detection. Porous supramolecular networks consist in three large families of distinct compounds, according to the interactions that they implement to maintain their structural integrity. We first distinguish the networks built by coordination bonds, called MOF (" Metal Organic Framework "). These porous networks have been widely studied for the incorporation of metal nanoparticles with various functionalities. The supramolecular networks obtained by covalent associations, named COF (" Covalent Organic Framework "), have been relatively little explored for the in situ growth of metallic nanoparticles. Finally, porous supramolecular architectures whose structural cohesion is ensured by weak interactions such as Hydrogen bonds, known by the acronym HOF (" Hydrogen-bonded Open Framework "), have, to the best of our knowledge, never been reported as a growth support for metallic nanoparticles. The aim of this thesis was to explore the possibility of using the porous supramolecular architectures based on hydrogen bonds as matrices for the controlled growth of noble metal nanoparticles. The first part of the thesis was devoted to the development of sub-micrometric crystals of a supramolecular porous architecture developed in the team and known under the pseudonym SPA-2 (" Supramoléculaire Porous Architecture "). Two reasons motivated our choice for this matrix: its porosity (estimated at 53%), as well as its channels decorated by pyridyl functions. The second part of this research led to the conception of the Au@SPA-2 hybrid material. The synthesis of this material proceeds by functionalizing the nanocrystals of SPA-2 with thiocyanates, followed by impregnation, then by a photo-reduction of the photosensitive gold molecular precursor (Me2SAuCl). The post-functionalization of the SPA-2 allows an effective impregnation in gold (5 to 10% of the total mass). The ultraviolet radiation exposure of the [Au-SCN]@SPA-2 material makes it possible to reduce the gold complex and then to generate nanoparticles. For our hybrid system, it is possible to control the size of gold nanoparticles (from 1 to 25 nm) by the duration of irradiation. This is the first synthesis of metallic nanoparticles in a porous supramolecular matrix based on the Hydrogen interactions ever reported. The third part of our research work focused on the synthesis of the Ag@SPA-2 hybrid material, with the same strategy that has been implemented for gold, namely the trapping of a photosensitive silver precursor (AgNO3), by an anion, here a chloride, located in the channels of SPA-2 network. Silver nanoparticles were obtained by photo-reduction, under UV light, of the material AgCl@SPA-2. The characterizations of this hybrid material revealed silver nanoparticles distributed uniformly within SPA-2 crystals. The matrix SPA-2 is recyclable. By simply dissolving the hybrid materials (Au@SPA-2 or Ag@SPA-2) in a slightly acidic aqueous solution, it was possible to isolate the metal nanoparticles from the molecular components of the SPA-2 porous network. From this solution, the initial SPA-2 matrix was regenerated by crystallization
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Korshed, Peri. "The molecular mechanisms of the antimicrobial properties of laser processed nano-particles." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/the-molecular-mechanisms-of-the-antimicrobial-properties-of-laser-processed-nanoparticles(731afee1-17f3-4698-b182-b604fb48492f).html.
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Microbial resistance to the current available antibiotics is considered a global health problem, especially for the Multi-Drug Resistant pathogens (MDR) including methicillin resistant Staphylococcus aureus. Recently nanoparticles (NPs) have been involved in variety of antimicrobial applications due to their unique properties of antibacterial effects. However, the molecular mechanisms behind their antibacterial activity are still not fully understood. In this study, we produced silver Ag NPs (average size 27 nm) and silver-Titanium Ag-TiO2 NPs (average size 47 nm) using picosecond laser ablation. Our results showed that both laser NPs had obvious size-dependent antibacterial activity. The laser Ag NPs with a size of 19 nm and Ag-TiO2 NPs with a size 20 nm presented the highest bactericidal effect. The laser generated Ag and Ag-TiO2 NPs with concentrations 20, 30, 40, and 50 Î1⁄4g/ml showed strong antibacterial effect against three bacterial strains: E. coli, P. aeruginosa, and S. aureus, and induced the generation of reactive oxygen species (ROS), lead to cell membrane interruption, lipid peroxidation, DNA damages, glutathione depletion and the eventual cell death. Both types of laser NPs at two concentrations (2.5 and 20 Î1⁄4g/ml) showed low cytotoxicity to the in vitro cultured five types of human cells originated from the lung (A549), kidney (HEK293), Liver (HepG2), skin (HDFc) and blood vessel cells (hCAECs). The antibacterial activity of the laser generated Ag and Ag-TiO2 NPs had lasted for over one year depending on the degree of air exposure and storage conditions. Frequent air exposure increased particle oxidation and reduced the antibacterial durability of the laser generated Ag NPs. The laser generated Ag NPs had lower antibacterial activity when stored in cold compared to that stored at room temperature. The antibacterial activity of laser generated Ag and Ag-TiO2 NPs were also compared with four types of commercial based-silver wound dressings (Acticoat TM, Aquacel® Ag, Contreet ®Foam, and Urgotul® SSD) against E. coli to inform future application in this area. In conclusion, laser generated Ag and Ag-TiO2 NPs have strong bactericidal effect and low toxicity to human cells which could be a type of promising antibacterial agents for future hygiene and medical applications.
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Baraket, Mira. "Élaboration et caractérisation de revêtements nano-structurés à base de nitrure de chrome par pulvérisation cathodique magnétron en condition réactive : propriétés mécaniques et tribologiques." Besançon, 2008. http://www.theses.fr/2008BESA2049.
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Cette étude porte sur l’élaboration et la caractérisation des propriétés de revêtements nanostructurés à base de nitrure de chrome (CrN) en vue de leur application sur des outils de coupe et/ou de mise en forme. Les dépôts ont été élaborés par pulvérisation cathodique magnétron en conditions réactives à partir de cibles métalliques (Cr, Si et Ag) sur un porte substrat statique et rotatif polarisable en courant continu (DC) et en radio fréquence (RF). La première partie de l’étude porte sur l’influence des principaux paramètres d’élaboration (pression partielle d’azote, polarisation du substrat) sur les propriétés du CrN. L’effet de ces paramètres a été suivi principalement sur les propriétés mécaniques (dureté, module de Young, contraintes internes, etc. ) et structurables. Une attention particulière a ensuite été portée à l’influence de l’addition de silicium aux revêtements de CrN. Les caractéristiques chimiques, mécaniques, tribologiques et structurales des dépôts de type CrSiN ont été étudiées en fonction de la teneur en silicium des films (nano-dureté, module de Young, DRX, MET, etc. ). Une étude par XPS a permis de mettre en évidence la présence de liaisons Si-N et de la phase Si3N4 dans les revêtements présentant des taux de silicium supérieur à 1 % at. %. La résistance à l’oxydation à haute température a également été étudiée en fonction des conditions de dépôt. Finalement, des revêtements multicouches nanométriques CrN/Ag et CrSiN/Ag ont été élaborés avec des périodicités comprises entre 8 et 24 nm. L’épaisseur de la couche d’argent ainsi que l’épaisseur totale ont été maintenues constantes pour l’ensemble des dépôts, le seul paramètre variable étant l’épaisseur de la couche de nitrure. L’influence de l’épaisseur de cette couche (CrN ou CrSiN) sur les propriétés mécaniques, tribologiques et sur la résistance à l’oxydation des multicouches est alors présentée et discutéeThe present work deals with structural, mechanical and tribological characterization of nanostructured chromium nitride (CrN) based thin films for cutting tool applications. Coatings are deposited by DC reactive magnetron sputtering from metallic targets (Cr, Si and Ag) on static and rotating substrate holders with RF or DC bias. The influence pf plasma parameters (nitrogen partial pressure and substrate bias) on the mechanical properties of CrN is studied. In order to improve its mechanical properties, silicon is then introduced to CrN thanks to silicon coupons placed on the erosion track of Cr target or by cosputtering of Cr and Si targets; The fraction of silicon into the coatings is then increased in order to achieve the formation of NC-CrN/A-Si3N4 nanocomposite. Chemical, mechanical, tribological and structural properties are studied as a function of silicon content using GDOES, EPMA, nano and microindentation, pin on discs, scratch tests, XRD, SEM and TEM techniques. Si3N4 phase is detected from 1 at. % of silicon by XPS measurements. An increase of the hardness is observed while adding silicon to CrN with two maximum at 5 and 10 at. % of silicon. The resistance to oxidation at high temperature is also studied. To improve the tribological properties of the films, silver is introduced as a solid lubricant in a multilayer structure of CrN/Ag and CrSiN/Ag in the nanoscale range. Multilayers periodicity ranges from 8 to 24 nm. The silver nanolayer and the total coating thicknesses are maintained constant at 4 nm and 2 µm respectively for all the coatings. The nitride layer thickness is the only parameter that has been modified in the multilayer coatings. The influence of the thickness of CrN and CrSiN monolayers on the mechanical and tribological properties is presented and discussed. The resistance to oxidation at high temperatures of all coatings is also examined
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Hausner, Susann, Martin Franz-Xaver Wagner, and Guntram Wagner. "Microstructural Investigations of Low Temperature Joining of Q&P Steels Using Ag Nanoparticles in Combination with Sn and SnAg as Activating Material." MDPI AG, 2019. https://monarch.qucosa.de/id/qucosa%3A33164.
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Quenching and partitioning (Q&P) steels show a good balance between strength and ductility due to a special heat treatment that allows to adjust a microstructure of martensite with a fraction of stabilized retained austenite. The final heat treatment step is performed at low temperatures. Therefore, joining of Q&P steels is a big challenge. On the one hand, a low joining temperature is necessary in order not to influence the adjusted microstructure; on the other hand, high joint strengths are required. In this study, joining of Q&P steels with Ag nanoparticles is investigated. Due to the nano-effect, high-strength and temperature-resistant joints can be produced at low temperatures with nanoparticles, which meets the contradictory requirements for joining of Q&P steels. In addition to the Ag nanoparticles, activating materials (SnAg and Sn) are used at the interface to achieve an improved bonding to the steel substrate. The results show that the activating materials play an important role in the successful formation of joints. Only with the activating materials, can joints be produced. Due to the low joining temperature (max. 237 °C), the microstructure of the Q&P steel is hardly influenced.
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Kuo, Ying-Jeng, and 郭英傑. "Synthesis of Ag-Fe3O4 composite nano-particles." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/87441725318289026864.
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碩士中原大學
化學研究所
96
Synthesis of Ag-Fe3O4 magnetic nanoparticles is carried out by coprecipitation method. The size of Ag-Fe3O4 magnetic nanoparticles is controlled by changing solution’s concentration and different preserver. The component and microstructure of Ag-Fe3O4 magnetic nanoparticles was characterized by XRD, UV, TEM, and EDS. The superparamagne- tism of Ag-Fe3O4 magnetic nanoparticles s was confirmed with a VSM. Synthesis of Ag-Fe3O4 magnetic nanoparticles was accomplished in two methods. Method one is Chemical reduction and oxidation. Silver ions were used as oxidation agent to oxidize ions of Fe(II) to form a solution containing both Fe(II) and Fe(III) ions. After precipitation with ammonia hydroxide, magnetic nanoparticles containing silver metals were obtained. Method two is synthesis of Fe3O4 magnetic nanoparticles using the microwave hydrothermal or coprecipitation method, then Synthesis of Ag-Fe3O4 magnetic nanoparticles were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the coprecipitation method. Method two results in better efficiency than those of method one. The best size we obtained in this study is 10±5nm.
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Chieh, Lin-Jen, and 林仁傑. "The texture and rotation movements of Ag nano particles and nano films." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/m45d8a.
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碩士國立中山大學
材料科學研究所
95
Thermal evaporator was used to coat a layer of silver nano-particles and thin film on (100) plane of rock salt . The experiment content can be divide into three parts . In the first part , the (100) texture of Ag nano-film and the evolution of the microstructure during annealing were studied . Little change in microstructure was found during low temperature annealing . In the second part , the salt surface was treated with deionized water and chlorine to try to align the Ag nano-particles on its surface . The effect of annealing on the texture and the defects of the Ag nano-particles were analyzed . The stacking fault was found to form early in the nucleation stage . In the third part , Ag nano-particles were scattered on the (100) texture , Ag nano-film and their rotation was studied by annealing at different temperature . Most Ag nano-particles were confirmed to rotate to a parallel orientation relationship with the Ag nano-film .
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Pei-FangCai and 蔡佩芳. "Capacitive deionization of seawater effected by nano Ag and Ag@C on graphene." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w647tu.
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碩士國立成功大學
環境工程學系
102
Drinking water is becoming scarce. Seawater is an abundant source for drinking water; therefore, development of the capacitive deionization (CDI) method for desalination is merit. CDI has the advantages of low energy consumption (only 0.1-0.6 kWh/m3), reduced secondary pollution, simple operation, and low-cost. CDI can be applied not only in desalination, but also water softening, removal of metals from groundwater and wastewater. Characteristics of electrode materials (e. g., conductivity, specific surface area and hydrophilicity (wetting ability)).have a great impact on the CDI process. In this study, graphene (rGO), nano Ag /rGO and Ag@C/rGO were prepared and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectra, and cyclic voltammetry. After reduction, rGO possesses the wrinkle surface and becomes porous. The hydrophilic function groups of GO was also removed which lead to the hydrophobic rGO. The specific capacitance of rGO can be high as 140.46 F/g. In addition, the removal efficiency of NaCl can reach up to 15% in a NaCl solution. The particles size of the Ag@C is in the range of 70-110 nm determined by small angle X-ray scattering (SAXS) spectroscopy. Ag and a small amount of Ag2O are found in the Ag@C nanoparticles, which was obtained by component-fitted X-ray adsorption near edge structure (XANES) spectroscopy. To enhance antimicrobial activity and electrical conductivity, nano Ag and Ag@C were added to promote the performance of graphene electrodes. The conductivity of the porous structure of the electrodes are enhanced in the presence the dispersed nano Ag and Ag@C. The NaCl removal efficiency from seawater can be as high as 45% with the nano Ag and Ag@C/rGO electrodes. Notably, the regeneration can reach 90% in the very short contact time (5 mins). In summary, a very effective method for CDI with an ability of de-infection has been developed in the present work.
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Chuang, Wan-Chen, and 莊宛珍. "The fabrication and characterization of Ag/Fe and Ag/Co nano-dot arrays." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9j9ryc.
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碩士國立中興大學
材料科學與工程學系所
106
In this study, ion beam assisted deposition (IBAD) is used for preparing bilayers thin films. Nano-dot arrays were fabricated by using electron beam lithography and followed by Ar-ion etching techniques. We divide the experiment into two parts. The first part is Ag/Fe thin films and nano-dot arrays, and the second part is Ag/Co thin films and nano-dot arrays. Ag/Fe thin films exhibit smooth surfaces with an average roughness of Ra ~ 0.9 nm, as measured by AFM. It consist of polycrystalline f.c.c. Ag, f.c.c. Fe, and f.c.c Fe-Ag at the interface (average grain sizes ~ 4.5 nm) by XRD and TEM. This reference Ag/Fe thin film exhibits soft magnetic properties with a coercivity of Hc ~ 17.6 Oe, as measured by VSM. By The Ag/Fe nano-dot arrays present smilar of that Hc at 300 K, with Hc (T) increasing with cooling (Hc~ 97.7 Oe at 2 K). In addition, asymmetric hysteresis loops observed at temperatures below 100 K signify different domain reversal modes, in contrast to the reference film that presents symmetric hysteresis loops. Ag/Co thin films also exhibit smooth surfaces with an average roughness of Ra ~ 1.4 nm. It consist of polycrystalline f.c.c. Ag, h.c.p. Co, and f.c.c CoO (average grain sizes ~ 5.8 nm). The degree of oxidation of cobalt increases as the depth of the films. The reference Ag/Co thin film shows a hysteresis loop with a coercivity of Hc ~ 105.6 Oe. The VNA-FMR spectrum of the reference Ag/Co bilayers have two modes: the uniform mode as well as a PSSW (perpendicular standing spin wave) mode, whereas a third low frequency mode (due to interactions between nanodots) can be found in the Ag/Co nanodots.
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Lee, Hsien-Hsuen, and 李賢學. "Chemical reduction of nano-sized Ag and its applications." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/64840104963785450520.
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博士國立清華大學
化學工程學系
93
Nanosized Ag was synthesized by chemical reduction method with PVP (Polyvinylpyrrolidone) as the protective agent. The reduction reaction was carried out by formaldehyde in an alkaline environment. The PVP and the by-product could be removed after proper washing process. Under optimum condition, nano-Ag of 28nm having 5% residual PVP could be obtained. The first application was to use nano-Ag to get polymeric conductive adhesives. Nano-Ag will improve the conductivity of the paste with silver flake filling close to the percolation threshold. However, when the silver flake content was above the percolation threshold, the addition of nano-Ag will increase the resistivity due to the smaller contact area between flakes and these nano-Ag powders. If the paste was made from nano-Ag and PVAc (Polyvinyl acetate) only, the viscosity can be easily adjusted by water content and therefore it can be coated by either airbrush or spin coating. The second application was to use this nano-Ag in the ink-jet printing process to make conductive lines on both glass and polyimide film using a commercial printer (EPSON R210). Conducting Ag lines with a resistivity of 5.6×10-6��-cm could be obtained after soft baking followed by the heat treatment at 260℃ for 10 minutes. The electroplating of copper makes a dense deposition over 10 �慆 in thickness onto the silver lines that will reduce the resistance of the circuit. That could serve as an alternative method to make the printed circuit board (PCB), which avoids the tedious and expensive photolithography steps. One can make the prototype fast and easily. The last application investigated here is as an antibacterial reagent that helps the cloth (JIS white cotton cloth) to kill off the Staphylococcus aureus during the AATCC-100 (American Association of Textile Chemists and Colorists) test. Cotton fabrics contain nano-Ag of 105.3ppm at the start still remains about 71% of the nano-Ag after water wash for 20 times. The antibacterial effect is >99.99% and 99.4% respectively. It was also demonstrated that these nano-Ag powder could be dispersed uniformly into Nylon fibers by a series of procedures of praying, drying, re-pelleting and spinning, and thus offers great potential as a functional additive to the synthetic fibers.
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周欣穎. "Photoreduction of carbon dioxide via nano Ag/TiO2 catalysts." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/24533059599605202212.
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Chun-ChiTsai and 蔡俊吉. "Study on photocatalytic properties of nano-Ag/SrTiO3 composite." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/75378634641914251331.
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碩士國立成功大學
地球科學系碩博士班
101
In this study, SrTiO3 and nano-Ag/SrTiO3 thin films are deposited on Si substrates by RF magnetron sputtering system. The composite thin films include Ag(25nm)/SrTiO3, Ag(20nm)/SrTiO3, Ag(22nm)/SrTiO3, and Ag film/SrTiO3. The amount of Ag nanoparticles in the SrTiO3 film is Ag(25nm)/SrTiO3＜Ag(20nm)/SrTiO3＜Ag(22nm)/SrTiO3＜Ag film/SrTiO3 (from SEM observation). X-ray diffraction analysis shows the SrTiO3 film has a cubic crystalline structure, so do the composite thin films. However, the (110) diffraction peak shifts toward lower angles with the increasing amount of Ag nanoparticles. Moreover, the XPS results show that Ag+ existed in the SrTiO3 lattice for samples of Ag(22nm)/SrTiO3 and Ag film/SrTiO3. This phenomenon will cause lattice distortion and induce stress in the film, which is corresponding to the XRD results. The information of UV-visible spectroscopy indicates the band gap becomes smaller with adding nanoparticles in the SrTiO3 film, but the band gap is nearly the same for all the composite films. The photocatalytic result shows that SrTiO3 thin film has a good photocatalytic decomposition for methylene blue, however, it is a little bad for composite films. The reason of worse photocatalytic efficiency for composite films may be an inappropriate density distribution of Ag nanoparticles. This would be difficult for charge transfer, or electron-hole pairs can not be separated effectively during photocatalytic process. One more reason may be due to the lattice defect which is resulted from Ag+ ions entering the SrTiO3 structure. This would make the defects become trap-centers to capture electrons. And then a decrease of electron numbers will be occurred for photocatalytic reaction, therefore, the photocatalytic efficiency becomes worse.
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Chung, Cheng-en, and 鍾承恩. "Synthesis of Ag Micro/Nano Structure and Polyaniline/Ag Complexes by Simple Metallic Coordination System." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/98413259797312844750.
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碩士國立中山大學
材料與光電科學學系研究所
103
In this study, A method to synthesize silver nanowires at relatively low temperature is demonstrated by using bases to attract silver ions and help silver ions to reduce to silver in polyol process. Here different bases in polyol process are asisted to the growth of silver nanowires, where bases play a role of the coordinate ion which grasp silver ions. In this case, ethylene glycol(EG) reduce silver ions to silver seeds first, then adding polyvinylpyrrolidone(PVP) to prevent silver seeds aggregating, finally adding bases to coordinate silver ions to help silver nanowires growing. SEM images indicate the different structures of silver in different bases. And XRD datas prove no other silver compounds is generated in the experiment. Silver nanostructures can be determined by UV-vis spectra because the surface plasmon resonance. We can see the UV-vis spectra of silver nanowires at 350 nm, and silver nanoparticle at 410~440 nm. The TEM images show the growth process of silver after adding the bases. Because of the reductive ability of –NH and the ligand bond between lone pair of nitrogen and silver ions, we can obtain nano- and microstructure of silver with special morphologies by synthesizing polyaniline and Ag at the same time. We developed a simple self-assembly polymerization method for the synthesis of Polyaniline/Ag composite without doping any acid reagent. SEM images indicate that the morphology of Ag depended on concerntration of Ag is wire or sheet. And SEM images also show that the morphology of Ag is micro-particle when the system of polymerization is under rapid stirring. XRD images indicate that the peaks of polyanilne become lower as the amount of Ag+ increase, which means Ag+ inhibit the polymerization of polyaniline. XPS images indicate that the oxidation of –NH- to –N= proves the connection between Polyaniline and Ag+. By blending the polyaniline/silver composite with PEDOT/PSS. We can obtain a recyclable conductive film of PEDOT/PSS where the polyaniline and silver are dispersed. The conductivity of the PEDOT/PSS is about 1~100 S/cm which is contributed by polyaniline.
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Hsieh, Chi-Hsing, and 謝繼興. "Studies on Graphene Oxide-Ag and Conductive Polythiophene Nano-Composites." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/a68te2.
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碩士國立臺北科技大學
有機高分子研究所
100
The aim of this study is to prepare graphene oxide-Ag /conductive poly (3-4ethylenedioxythiophene) nano-composites. We blend graphene oxide before and after the surface attractive of nano Ag and poly(3-4ethylenedioxythiophene) - polystyrene sulfonic acid that synthesized. The dispersion of graphene in composites and conductivity were tested and discussed. The polythiophene derivatives we synthesized are monomer 3-4ethylenedioxythiophene、poly(3-4ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT:PSS) polymer. There are two parts about the surface modification of graphene, the first part of the Hummers method oxidized graphene (GO) ; second part of the nano Ag ion attract mechanism by chemical reduction of graphene oxide to make nano Ag ions to restore nano Ag and graphene. We blend graphene oxide before and after the surface attractive of nano Ag and poly(3-4ethylenedioxythiophene) - polystyrene sulfonic acid that synthesized. The dispersion of graphene in composites and conductivity were tested and discussed.The products were characterized by NMR、FT-IR、TGA、UV-vis、XRD、Raman、XPS、AFM、SEM、TEM、Milliohmmeter identification of samples of characteristics.
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Meng, Yun Chung, and 鍾孟雲. "A Study of Parameters and Suspension Stability of Nano-Au/Ag Colloid by Electric Spark Discharge Method and Application of Nano-Ag to Restrain Aspergillus Niger." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/er9y75.
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碩士國立臺北科技大學
電機工程系所
104
In this study, the electric spark discharge method is used to fabricate the nano-Au colloid by the micro-electrical discharge machine. In the deionized water, the arc wore down the surface of the electrodes under the circumstances of standard temperature and pressure and it is done without adding any other chemical materials. The nano-Au particles is gained. Analyzed by UV-Visible Spectroscopy, Zetasizer, Scanning Electron Microscope and Energy Dispersive X-ray Analysis, the nano-Au colloid fabricated in the discharge pulse time of 10-10us and optimal PID has highest concentration and best suspension stability. Comparing the method of magnetic stirring and sonication to make the nano-Au and nano-Ag to suspend in the DW, the nano character of the sonication method is better than the other because of the analysis of the precision instrument. In the experiment of Precipitation Research, the nano-Au and nano-Ag can stabilize in 520nm and 392nm of surface plasmon resonance after a few days. Comparing the nano-Au fabricated by electrical discharge machine and micro-electrical discharge machine, the Zeta of the latter is lower than the former which means it has better suspension stability. This study also make the little exploration of nano-Ag restraining the growth of the Aspergillus Niger. By observing the Aspergillus Niger in the MEA and 3M Petrifilm, the higher of the concentration of the nano-Ag, the lower of the number of the Aspergillus Niger. It is discovered that the nano-Ag can stop the Aspergillus Niger to grow.
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Bachmann, Andreas R. "Gestufte Cu-Oberflächen und Ag-Nano-Streifen: atomare und elektronische Struktur." Doctoral thesis, 2002. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2002111519.
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I. Atomare Struktur Mittels Rastertunnelmikroskopie und Beugung langsamer Elektronen wird die atomare Struktur von vizinalen Cu(111)-Oberflächen untersucht. Der mittlere Stufenabstand auf den untersuchten Oberflächen deckt einen Bereich von ca. 1.0-2.5nm ab. Auf allen diesen Oberflächen wird ein regelmäßiges Stufenarray gefunden.Es wird gezeigt, dass das System Ag/Cu(223) ein gutes Beispiel für den Effekt der Selbstorganisation auf Kristalloberflächen darstellt. Durch die Ag-Adsorption im Bereich von 0-1ML wird eine periodische Facettierung der Cu(223)-Oberfläche induziert. Die Gleichgewichtsstruktur setzt sich aus Ag-bedeckten Facetten zusammen, die mit reinen Cu-Streifen alternieren. Die Breite der Cu- und der Ag-Streifen kann in einem Bereich von 3-30nm über die Ag-Bedeckung kontinuierlich eingestellt werden. II. Elektronische Struktur Mittels winkelaufgelöster Photoelektronen-Spektroskopie mit Synchrotron-Strahlung wird der Einfluss von Stufen auf den Oberflächenzustand von vizinalen Cu(111)-Oberflächen untersucht. Veränderungen bzgl. der Bindungsenergie werden im Rahmen eines eindimensionalen Kronig-Penny-Modells interpretiert. Als Ursache für das Kippen der Ausbreitungsebene bei einer kritischen Terrassenbreite (~1.7nm) wird die Überlagerung des Oberflächenzustands mit Volumenzuständen und dem damit verbundenen Übergang zur Oberflächenresonanz diskutiert. Bei dem System Ag/Cu(223) wird der Oberflächenzustand innerhalb der Cu-Streifen zum einen durch die Ag-Streifen lateral begrenzt, zum anderen ändert sich der mittlere Stufenabstand innerhalb der Cu-Streifen. Die hierbei gewonnenen Ergebnisse können im Vergleich mit den Ergebnissen diskutiert werden, die an den sauberen vizinalen Oberflächen gewonnen wurden. Mit größer werdender Bedeckung bildet sich ein neuer Zustand, dessen Ursprung in den Ag-Streifen liegt. Die beiden Zustände können in ihrer energetischen Lage und in ihrem Dispersionsverhalten unterschieden werden.
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Wei-KangHsieh and 謝濰岡. "Investigation of thermal treatment for ZnO photodetector with Ag nano-interlayer." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/97922299881154848416.
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Pai, Chien-Jung, and 白倩榕. "The Fabrication and Antibacterial Activity of PEO/ Ag/ TiO2 Nano-fibrous Membrane." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/42k436.
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碩士國立臺北科技大學
有機高分子研究所
98
Poly(ethylene oxide) (PEO) is a green material of white-color, odorless and pollution-free. With the Characteristic of environmental compatibility, the complete degradation, water-solubility and the safety and convenience of usage, PEO has been attentioned and studied by the whole world and becoming a high value polymer material. PEO is soluble in organic solvent with low toxicity like ethanol to form polymer solution. and afterward, it could be fabricated nano-fibrous membranes by electrospinning. The first step of this experiment was to prepare PEO/ TiO2 composite nano fibrous membranes with diffirent weight percentage of nano titanium dioxide powders by electrospinning. The morphology of fibrous membranes was investigated by the SEM and the results showed that its average diameters were in the range of 635nm~867nm. The EDS results showed the featuring peak of Ti. The spectra of FTIR showed the Ti-O-C featuring peak was rised with the increasing of TiO2 concentration. The membranes with 4 wt% of TiO2 had the best mechanical properties. As to obtain the thermal properties of PEO/ TiO2 membranes, the decomposition temperature of membranes and its relationship to the weight loss were examined by TGA. In addition, the variation in Tm and Tc were analyzed with DSC. The Tm and Tc of PEO polymer had little doing with the addition of TiO2 which was taken account of the low thermal collapse temperature. Furthermore, the characteristics of inhibition of bacteria growth and UV cut of PEO fibrous membranes would be achieved by adding TiO2. From the experimental results, it showed that both were rised with the increasing of TiO2 concentration. The second step of this experiment was to add nano silver solution into PEO/ TiO2 polymer solution to produce PEO/ Ag/ TiO2 nano-fibrous membranes by electrospinning. The results of SEM showed that its average diameters were in the range of 425nm~530nm, and showed the featuring peak of Ag in the results of EDS. From the data of ATR-FTIR test, it was concluded that neither new groups were made nor phenomenon of displacement was happened. Also, the results of DMA showed that the mechanical properties of membranes were all rised by adding Ag. The thermal properties were analyzed by DSC and TGA which showed the rise of Td and the decline of enthalpy with Ag nano particle. As for the effect of antibacterial, it showed higher than 99% of inhibiting in the growth of staphylococcus aureus and klemsiella pneumoniae.
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Cheng, Wan-Chun, and 鄭婉君. "The Antibacterial Activity of PVA/Ag/TiO2 Nano-fiber membranes via eletrospinning." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/u5u868.
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碩士國立臺北科技大學
有機高分子研究所
102
In this study, nano-fiber membrane was prepared by electrospinning method, the substrate is polyvinyl alcohol, a water-soluble polyvinyl alcohol is harmless, while titanium dioxide has antibacterial, non-toxic, deodorization, hydrophilicity and other characteristics can be an ideal environment spun fibers, expect by this study to make more extensive use of polyvinyl alcohol fiber. During the manufacturing process of polyvinyl alcohol by the use of a solvent is not a burden on the environment. Adding different proportions of nano titanium dioxide as a function of material prepared PVA / TiO2 fiber composite film, and then by adding an aqueous solution of silver nanoparticles prepared PVA / Ag / TiO2 fiber composite film. The morphology of fibrous membranes was investigated by the SEM and the results showed that its average diameters were in the range of 150nm~270nm. The EDS results showed the featuring peak of Ti and Ag. The XRD analysis showed TiO2 and Ag peak. The spectra of FTIR analysis of its surface features functional groups and found no other peaks appeared, and there is no shift phenomenon characteristic peak, so adding inferred nano-titanium dioxide and nano silver aqueous solution of polyvinyl alcohol does not destroy the original the chemical structure and physical blending. DSC and TGA thermal properties of the analytical results, with the addition of TiO2 powder to enhance the pyrolysis temperature increases. The UV / Visible resistance test, found that as the amount of TiO2 powder to increase its potential with enhanced UV resistance. The antibacterial effect, increases the amount of TiO2 powder, antibacterial effect is an increasing trend, and found that nano silver antimicrobial solution so that the rate of increase and achieve sterilization effect. These results show that adding the appropriate amount of aqueous nano silver solution, can enhance the photocatalytic efficiency and excellent antibacterial properties.
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Hung, Ming-Chean, and 洪銘謙. "The study for depositing nano-Ag particles on activated carbon fiber fabrics." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/57662827520266573188.
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碩士逢甲大學
材料科學所
96
This study uses the newest activated carbon material, activated carbon fiber fabric (ACFF) No. FAW1001 & FAW1502 made by Challenge Carbon Company, to support nano-Ag particles. We treated ACFF for 0.5 hr, 1.5 hr, and 2.5 hr with 1 M and 5 M nitrate acid at 80 ℃, then immersed it for 1 hr in 0.001 M nitrate silver solution in a vacuum, utilizing the principle to ion change or to oxidize/reduce. We made silver ion uniform bending on ACFF and dry at 120 ℃ for 24 hr, then heat- treated at 400 ℃ in a furnace. The silver ion bond was transition to covalent bond after high temperature strain, so we obtained ACFF support nano-Ag particles well mixed. With use of FE-SEM one can observe nano-Ag particles well mixed on ACFF after high temperature treatment, particle size averaging 10~30nm. Two we can find that treated ACFF’s time increase with 1 M and 5 M nitrate acid at 80 ℃. The ACFF’s surface become smooth. It cause nano-Ag particles to heat aggregate become big particles. Big particle size averaging 50~60nm. The measurement of high resolution surface area and porosimetry analyzer (BET), found the depositing nano-Ag particles on ACFF’s t-polt micropore area value was 55.8%(1MEA-Ag) and 64.0%(5MEA-Ag) of ACFF’s t-polt micropore area value.The main reason was nano-Ag particles clogged the ACFF’s micropore due to the value decrease.This thesis involves the commercial problem, the detailed content has already been deleted.
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Chang, Hsiang-Chun, and 張翔鈞. "Surface Plasmonic Waves on Ag Surfaces Excited with Asymmetric Nano-Groove Structure." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/60129107310786005392.
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碩士國立中正大學
物理系研究所
104
We excited surface plasmonic waves by illuminating a focused 532nm laser beam from below on to groove structures which are fabricated with electron beam lithography(EBL) and oblique deposition of 100nm Ag on a PMMa film covered ITO glass substrate. We characterize the propagation of surface plasmonic waves with Near-field scanning optical microscopy(NSOM). We discovered that the surface plasmonic waves intensity distribution varies with groove width in a asymmetric fashion, which provides a possible method to control the propagation direction of surface plasmonic waves.
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Ji, Yi-jen, and 紀一真. "The rotation process and interfaces of the nano NiO and Ag grains." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/76069583572867936411.
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碩士國立中山大學
材料與光電科學學系研究所
98
A nanofilm rotation method is developed to study the rotation of nanograins and the formation of various low energy interfaces. Epitaxial NiO and Ag nanofilms are prepared by ion beam sputtering onto the (100), (110), (111) and (112) surfaces of NaCl single crystal. By overlapping of the above films with an angle difference, and annealing at relatively low temperatures the nanograins are induced to rotate till a stable interface is reached. The rotation process and the stable interfaces are determined by transmission electron microscopy. Many new interfaces between mixed planes are found, and their orientation relationships and structures are analyzed. The rotation speed increase with temperature and is fast above 200oC.
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Hung, Sung-Wei, and 洪松慰. "Syntheses and Characterization of Multi-functional N-doped Nano-ZnO Visible Light Photocatalyst and ZnO-Ag Nano-composite Particles." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/nwa54g.
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碩士國立臺北科技大學
材料科學與工程研究所
95
In this study, N-doped ZnO nanoparticles with rod-like and tetrapod-like morphologies were synthesized on a mass scale using the DC thermal plasma approach. The N-doped ZnO nanoparticle has a strong absorption below 420 nm and significant absorption in the visible range from 450 to 650 nm. Ag nano-colloids were prepared by chemical reduction with the presence of citrate ion, which modified the surface properties of Ag nanoparticle. After complete mixing, the Ag nanoparticles can adhere to the surface of N-doped ZnO nanoparticle to form ZnO-Ag nano-composite particles (NCPs) due to the attraction between the positively charged ZnO surface and the negatively charged Ag surface. The experimental results indicate that ZnO-Ag composite has semicoherent interface boundary. The amount of Ag nanoparticles absorbed on the surface of N-doped ZnO nanoparticle, is related to the surface charge density of the N-doped ZnO nanoparticle. Citrate ions play the role of selective absorption site on N-doped ZnO nanoparticle surface. Although decomposition efficiency of methylene blue (MB) under UV irradiation does not appear to differ from each other, ZnO with a higher N-doped concentration has better decomposition performance under visible light illumination. This is due to that oxygen vacancies prolong the recombination of electron and hole. The decomposition performance of methylene blue (MB) by ZnO-Ag NCPs significantly exceeded that by N-doped ZnO nanoparticles under UV irradiation, because the Ag nanoparticles act as electron traps, which enhances electron-hole separation. However, there is almost no difference in methylene blue (MB) decomposition efficiency between the ZnO-Ag NCPs and the N-doped ZnO nanoparticles under visible light. The Ag nanoparticles behave incompletely equivalent under UV irradiation and visible light due to the surface plasmon resonance absorption of Ag nanoparticles, which is only induced by visible light. Ag nanoparticles can decompose methylene blue (MB) during illumination with visible light. Increasing the N-dopant concentration of ZnO nanoparticles improves anti-bacterial performance because oxygen vacancies prolong the recombination of electron and hole. The anti-bacterial performance of N-doped ZnO nanoparticles under visible light is better than that of commercial ZnO nanoparticles. The N-doped ZnO nanoparticles exhibit additionally the intrinsic photocatalytic activity for anti-bacterial performance. N-doped ZnO nanoparticles modified with a coating of Ag nano-dots on their surface perform as well as N-doped ZnO nanoparticles do, during 3 hours of illumination with visible light with a wavelength of 543 nm. However, the performance of ZnO-Ag NCPs is improved by approximately two orders of magnitude in the dark. Mildew resistance tests indicate N-doped ZnO nanoparticles has excellent performance of zero-level.
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Yang, Wen-han, and 楊雯涵. "Study of E. coli Removal by a Novel Nano Ag Impregnated Disinfection Material." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/mtmrtx.
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碩士逢甲大學
環境工程與科學所
100
Silver is well-known for its strong bactericidal properties against a broad range of microorganisms and without harmful disinfection by-products formation. In this study, a nano-silver impregnated media (NAg-ball) was used to replace the regular disinfectants to inactive E. coli in water. Using of NAg-ball has the advantages of high flexible to raw water quality, easy operation and low maintenance required, and the high potential applying on water supply especially in the mountain area to improve and assure water-use safety. From the tests of Toxicity Characteristic Leaching procedure (TCLP) and submerged in different pH conditions a few metal release from Nag-ball, but the release amount still does not exceed the regulations and standards set by the government. After 24 h of contact with one piece of NAg-ball, about 99 % removal of E. coli from the one liter of water sample with an initial bacteria loading of 103 - 105 CFU/ml was observed. After 28 day repetitive use, the inactivation of NAg-ball was down to 83%, however, then immediately back to 94% by a surface cleaning done on NAg-ball. A periodical surface cleaning would be therefore suggested to maintain the high inactivation lasting of NAg-ball. it is found that no significant difference on the bactericidal efficiency of two different water temperature (14℃ and 33℃) conditions. From the results of dosage test, the optimal dosage is 1:2 (1 piece of ball : 2 liter of water sample volume ) for the 10 L and 1:5 for 50 L in the lab scale test and 1:20 for 500 L field scale. It is clearly found that a less ball dosage with much treated water volume indicating the synergy effect is activated by more NAg-ball additions. Therefore, lower dosage shall be expected to treat the same load of E. coli for further larger scale water. In summary, the NAg-ball has a good bactericidal effect on E. coli, and it is easy, flexible to operate.
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Tsai, Tsung-Lun, and 蔡宗倫. "Characterization of nano-triangular Ag adsorptive photocatalyst and its disinfection for aquatic pathogens." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/32214823876217791794.
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碩士國立臺灣海洋大學
機械與機電工程學系
102
The increases in catalytic photolysis efficiency of the surface modified ATO (anodic titanium oxide) by doped nitrogen or/and adsorbed triagular silver nanoparticles were attributed to the greater light absorbance than that of the ATO. In addition to the enhanced inherent ATO absorbance at 378.5 nm in as much as the surface-plasmon enhancement of the band emission, additional light absorbance peak occurred at the wavelength around 578 nm was contributed by the triangular Ag nanoparticles adsorbed on N-doped TiO2. All surface modified ATO catalysts exhibited stronger removal effect under the irradiation LED (a combination of two wavelengths at 375 nm plus 450 nm). The Streptococcus iniae (S. iniae) cells reduced from 107 CFU/mL to 104 CFU/mL under the LED exposure for 4 hours, which was about three powers of exponent reduction. Even for a short time of one hour, the number of Tetrahymena corlissi (T. corlissi) decreased drastically from 104 number/mL to 0 number/mL under the LED exposure, which was about four powers of exponent reduction.
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Tang, Tsung-Yeh, and 湯宗曄. "Preparation and photocatalytic activity of Ag2O nps and Ag2O/Ag-ZnO nano-composites." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/48145774380481253382.
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Wu, Jia-Shin, and 吳嘉信. "The application of Cu-Ag nano/submicron composite particles in microelectronic interconnections and bonding." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/y7mjz5.
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碩士國立中興大學
材料科學與工程學系所
101
The combination of excellent electrical conductivity (only 6 % less than that of Ag) and low cost makes copper a good selection for interconnect materials. Taking the advantage of the drastically reduced sintering temperature of nano-sized particles (NPs), copper NPs attract considerable attention and have been regarded as a promising material for circuit fabrication. However, rapid oxidation of Cu NPs is a fatal demerit. In order to improve the oxidation resistance, Cu-Ag composite particles with nano-size or submicron size are developed for the bonding and interconnect applications in this study. The first part of this study is to achieve Cu to Cu bonding using the pastes with CucoreAgshell NPs synthesized by the successive reduction method. Optimal conditions for solvent formula, bonding temperature and load are suggested. Under the bonding pressure of 10MPa at 250oC, the shear strength of the joints thus produced reaches 23MPa. To cut the cost and realize mass production, the second part of this thesis develops Cu@Ag core-shell submicron particles (SMPs) using commercial copper oxide particles. A low temperature two-phase reduction method has been successfully developed, which can transform copper oxide particles to copper particles efficiently (at 250oC for 30 minutes) without aggregation and coarsening. Subjected to an electroless deposition of Ag, Cu@Ag core-shell SMPs can be prepared. The TGA analysis suggests that those Ag coated Cu particles show an excellent anti-oxidation ability and possess an oxidation temperature of about 100oC higher than that of Cu particles. Under a reductive atmosphere, the pastes mixed with Cu@Ag SMPs and Ag SMPs obtained from one-step spray pyrolysis can turn into conductive films with the electrical resistivity of 1.1X10-5 Ω‧cm.
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CHANG, CHIA-CHI, and 張佳奇. "Thermal Conductivity of Epoxy Composites With Ag Particles Doped Al2O3 Micro/nano Fibrous Fillers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/60210962430892487244.
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碩士國立高雄應用科技大學
化學工程與材料工程系博碩士班
104
As the development of electronic components in the direction of miniaturization, high-power, and high integration, it requires more and higher performance, so the waste heat generated by the operation of components, need to be ruled out quickly, otherwise it will reduce the performance of electronic components. High thermal conductivity polymer composite materials with high thermal conductivity and high-performance are the most widely used in electronic components. This study is using electrospinning method to prepare high thermal conductivity micron network Al2O3-Ag fillers, and applied to enhance thermal conductivity of Al2O3-Ag/epoxy composites. Commonly, to enhance thermal conductivity of polymer matrix composite via a large amount of thermal conductivity powders loading in matrix (ex: AlN). From the images of SEM, indicated the Al2O3-Ag fillers with 1-D micron network structure and high aspect ratio (> 50), and identified as cubic system Ag and rhombohedral system Al2O3 by XRD and TEM. From the spectra of FT-IR, confirmed the material surface grafted with siloxane. By a four-point probe tester detected the volume resistivity value, confirmed the Al2O3-Ag/epoxy composites is non-conductive material. The Al2O3-Ag/epoxy composites using a thermal conductivity meter (Hot-Disk) to detect the heat transfer coefficient, was prepared the Al2O3-Ag fiber and modified Al2O3-Ag fibrous fillers, as 50 wt% addition amount of epoxy composite, the thermal conductivity were 0.77, 0.60 W/mK, respectively. And had 285% and 200% enhancement in thermal conductivity, respectively. This conclusion can be observed the filler which were modified has the better thermal conductivity, by using SEM observe the surface morphology of cross section can be found within the composites material is modified through the addition of materials and organic substrates interface significantly reduced, which can be attributed to the additional material bonded with an epoxy resin. DMA detects storage modulus and glass transition temperature, in addition to silane internal substrate material can effectively inhibit crack growth and storage modulus increases, but because of this situation hinders the crosslinked epoxy resin.
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Bachmann, Andreas R. [Verfasser]. "Gestufte Cu-Oberflächen und Ag-Nano-Streifen : atomare und elektronische Struktur / von Andreas R. Bachmann." 2002. http://d-nb.info/970380801/34.
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Hsu, Chun-Kuo, and 徐俊國. "A study of adsorption dynamic model of nano Au, Ag, Chitosan coated activated carbon filters." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/a6rqqn.
Full textAbstract:
碩士國立臺北科技大學
環境規劃與管理研究所
102
There are many advantages and disadvantages of filters technologies of removal air pollutants in the market. The study focuses on gaseous pollutants such as Formaldehyde (HCHO), Volatile Organic Compounds, VOC (C3H6), Carbon monoxide (CO) and bioaerosol (Bacteria and fungi) . To take activated carbon filters added nano gold (Au)- silver (Ag) , nano Ag and chitosan , tested removal efficiency and adsorption capacity by experimental studies. Moreover ,To be compared with the field studies and experiment studies. The study simulated and discuss air pollutants by used pseudo-first-order model and pseudo-second-order model , in order to achieve appropriate simulation. The experimental results showed that the removal efficiency of HCHO was increased by 16.33% when chitosan added , but not obvious on VOCs and CO. The removal efficiency of both HCHO and CO were increased by 20% and 7.11% when nano Au-Ag added in activated carbon filter. The parking lot studies showed the removal efficiency of CO was increased by 7.48% when nano Au-Ag added in activated carbon filter. The removal efficiency of Bacteria was increased by 19.57% , Fungi was increased by 17.1% when nano Ag added in activated carbon filter, the removal efficiency of Bacteria was increased by 35% when chitosan added. The kindergarten (KG) studies the removal efficiency of HCHO was increased by 9.02% when nano Au-Ag added in activated carbon filter. The removal efficiency of HCHO was increased by 42% when chitosan added in activated carbon filter. Adsorption dynamic model results HCHO 、 C3H6 and CO coincided pseudo-second-order model, it is effectively increased HCHO ,C3H6, CO adsorption capacity by added nano Au-Ag and nano Ag.
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Der-LiYeh and 葉德立. "The plasmonic properties of dome-shape nano-rod antenna arrays with Au/Ag/Au multilayers." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/09068309512232726321.
Full textAbstract:
碩士國立成功大學
光電科學與工程學系
102
A theoretical study of the optical properties of metallic dome-shape nano-rod antenna is presented. Such nano-rod antenna exhibits localized surface plasmon resonances under normal incidence. A longitudinal Fabry-Perot like resonant mode can be excited in the array structure. The shape sharpness results in mixing effect but overall contributes to the field enhancement. Additional metal film substrate can serve as an imaging plane to tune the resonant wavelength and enhance the field confinement. Our finding will serve as a guideline for future sensing applications using such nano-rod arrays.
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LI, JIA-HONG, and 李佳鴻. "Optical Properties of SiO2 Nanosphere Opal Photonic Crystals Decorated with Self-assembled Ag Nano Chains." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97469206356768158820.
Full textAbstract:
碩士國立中正大學
物理系研究所
104
We decorated nano particles of different metal structure on SiO2 nano-spheres on the top layer of SiO2 opal photonic crystals using glancing angle deposition (GLAD) method ,then we annealed the metal films to allow the metal to agglomerate forming chain structure.We investigated their effect on the optical properties of the opal. Keyword:opal, Ag chain structure, Fluorescence, Enhancement of fluorescence.
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Huang, Sheng-jie, and 黃聖絜. "A Study on Fabrication and Functional Properties of Polyurethane/ Nano Ag@ Coir Charcoal Composite Films." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/87959203190645863252.
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Zhang, Jia-Rong, and 張家榮. "Study of Blending Ag Nano Particles in the Active Layer of the Organic Solar Cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/38829255595851755786.
Full textAbstract:
碩士明志科技大學
化學工程研究所
101
In recent years, the rapid development of organic solar cells and have good results, which has low temperature process, simple process, easy to manufacture large area, low cost, light weight and flexible, etc., but its biggest drawback is inefficient, so the main purpose of this study to explore the process parameters and blending silver nanoparticles to enhance the efficiency of the photoelectric effect of battery. In this experiment, P3HT and PCBM as the active layer of the body, P3HT absorption in the visible range with a high degree of absorption for Donor materials; PCBM has good electron transport properties, can miscible with P3HT, and the HOMO and LUMO energy levels are more match with P3HT. The experimental investigate the effect of change to a different annealing temperature and P3HT/PCBM ratio, and decided to optimum preparation conditions of organic solar cells. Experimental results show that the organic active layer after annealing treatment, to obtain a better crystallinity, which will be more regularly arranged of molecules; when P3HT/PCBM ratio at 1:0.8, the annealing temperature of 120˚C absorption in the visible range of the active layer has the best absorption. Due to the charge transport is low rate on organic polymer material, this study blended nano inorganic particles ways to improve the charge mobility. Literature has mentioned nanosilver has surface plasmon resonance properties, therefore this experiment optional inorganic silver particles. Experimental results show that the unblended silver battery it’s photoelectric conversion efficiency was 0.43%, while the blend of silver nano-particles it’s the photoelectric conversion efficiency is improved to 0.77%.
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Wu, Wei-De, and 吳韋德. "Study of Ga-doped ZnO thin film with Ag nano-particles apply on pulse sensor." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/994fv3.
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Xu, Jia-Yao, and 許嘉堯. "The rotational movement and coalescence of Au、Ag and Pt nano-grains on NiO (100) plane." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/umwq3t.
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Zhange, Xin-Ru, and 張心如. "A Study on Functional Properties of PA 6/Nano-Ag Composite Prepared by In-Situ Polymerization." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/dh35tj.
Full textAbstract:
碩士國立臺北科技大學
有機高分子研究所
99
In this study, the nano-silver solution were added during the process of PA 6 (Polyamide 6, Nylon 6) in situ polymerization to prepare composite with anti-bacteria function. It was in the course of synthesizing ε-caprolactam (CPL) to form PA 6, the nano-silver solution with various ratio were added. Such PA 6/nano-Ag composite were prepared by purification and vacuum drying procedure. The effect on the mechanical, thermal, chemical, physical and anti-bacteria function properties of PA 6/nano-Ag composite with various loading of nano-silver solution were investigated. The technique used in composite preparation taking the PA 6 as the matrix, the nano-Ag as the functional additive, preparing a functional nano composite with impurity, to synthesis different ratio of 0.5, 1.0, 1.5, 2.0, 2.5 wt% addition content composite masterbatch. Properties tests will be divided in to two parts, basic and functional test. Basic tests included mechanical properties of tensile test, thermal properties of thermal gravimetric analysis(TGA) and differential scanning calorimeter(DSC) analysis, physical properties of relative viscometer, scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis, chemical properties of Fourier transform infrared spectroscopy. Functional test included AATCC 90 anti-bacteria test. The mechanical properties showed the addition of nano-silver solution will reduce the toughness of composite, as the matter of 2.5wt% addition will reduce maximum loading stress and fracture elongation by 26.38% and 24.17%. At thermal properties part, the reduction of initial decomposition temperature and melting point mach with the downward trend. The physical properties showed the addition of nano-silver solution will reduce the relative viscosity of composite. SEM observations show that the addition will not cause significant surface differences. EDS analysis showed the nano-silver content distributed on the surface evenly. The data of FTIR analysis showed neither new group was made nor phenomenon of displacement was happened as predicted. The anti-bacteria properties can be observed the anti-bacteria function of composite increased with addition of nano-silver solution, it reaches effect of the AATCC100 bacteria-inhibitory standard with 2.0 wt% loaded.
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KUAN, CHAO, and 趙冠翔. "Electrochemical etch of p-Si(100) dispersed with nano-Ag particles in the NH4F/H2O2 solution." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/24392306941916113793.
Full textAbstract:
碩士國立中央大學
機械工程研究所碩士在職專班
97
The aim of this work was to prepare porous silicon(PS) by electrochemical etch of p-type silicon (100) coated with nano-Ag particles in an aqueous solution of ammonium fluoride mixed with hydrogen peroxide. DC potentiodynamic polarization was conducted and the anodic polarization curves were analyzed to find the optimal potentials for potentiostatic preparation of the PS. The results displayed that deep holes were produced electrochemically on the silicon dispersed with nano-Ag particles in the solution containing ammonium fluoride and hydrogen peroxide. The corrosion potential shifts to active direction and the etching rate increases with increasing the reaction temperature and the concentration of hydrogen peroxide. The optimal temperature to obtain porous silicon was at 60℃ to obtain the highest depth. The activation energy is estimated to be 48.4 KJ/mol for the etching system by the Arrhenius plot.
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Luo, Yi-Chia, and 羅苡嘉. "CO Oxidation on Au-Ag Alloy Nano-Catalysts and the Kinetic Study under H2-Rich Atmosphere." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/54110714105093910904.
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碩士國立臺灣大學
化學研究所
95
The first part in this thesis, we demonstrated surface functionalized mesoporous SBA-15 thin film as supporting host to confine the gold and silver alloy nanoparticles. We then show its PROX activity is surprisingly high. Proton exchange membrane fuel cells (PEMFC) have been extensively studied in the past decade. Pure hydrogen source is the ideal fuel for mobile energy systems. However, the Pt anode catalysts would be significantly poisoned by traces of CO in reformed gases. To fulfill the high purification requirement, the preferential oxidation of CO (PROX) appears as the most promising approach and the lowest cost technique. In general, the premise for good PROX performance is to choose a catalyst with more oxidation activity for CO than for H2. Recently we found that Au-Ag alloy catalyst showed a relatively high activity and selectivity. In the second part of this thesis, Au-Ag alloy catalyst supported on MCM-41 was used for kinetic measurements of CO oxidation under H2-rich atmosphere. For this catalyst, it not only performs high CO conversion and CO2 selectivity, but also shows satisfactory stability. Many characterization techniques were used to study the catalyst system, such as nitrogen adsorption, TEM, XRD, EXAFS (X-ray absorption fine structure spectroscopy), and UV-Vis spectroscopy. Especially, EXAFS was employed to determine the coordination number and the degree of alloying formation.
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Klyatskina, E., C. Cancellieri, M. Chodi, L. Jeurgens, B. Straumal, and J. Janczak-Rusch. "Effect of Ge addition in the thermal stability and microstructure Ag/Ge/AlN nano-multilayer system." 2017. https://ul.qucosa.de/id/qucosa%3A31731.
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Luo, Yi-Chia. "CO Oxidation on Au-Ag Alloy Nano-Catalysts and the Kinetic Study under H2-Rich Atmosphere." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2307200720103600.
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Jheng, Chian-fang, and 鄭千芳. "The study on preparation and the characterization of nano-composite Ag/TiO2 photocalayst by sol-gel method." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/52487026428069564089.
Full textAbstract:
碩士國立雲林科技大學
工業化學與災害防治研究所
93
In this study, nano-composite Ag/TiO2 phototcatalyst has been prepared by sol-gel method with addition of silver. The effect of different Ag/TiO2 molar ratios and annealed temperature on the properties of nano-composite photocatalyst material has been discussed. The samples were characterized by various analytical techniques, such as Thermogravimetric Analysis(TGA), UV-Visible Diffuse Reflectance Spectroscopy(UV-Visible), X-Ray Diffraction(XRD), low temperature N2 adsorption(BET), Transmission Electron Microscope(TEM) and Scanning Electron Microscope(SEM). The photocatalytic activity of the prepared sample was evaluated by photolysis solid–liquid phase of methylene blue and the solid-gas phase of aldehyde and anti-bacterial activity. The result of TGA reveals that the steady state temperature is 500℃ for titania, but the nano-composite Ag/TiO2 improves the steady state temperature up to 600℃. The result of XRD reveals that nano-composite Ag/TiO2 shows a significance of phase transition from anatase to rutile in comparison with pure titania. The temperature change for phase transition from 600℃(TiO2) to 700℃(Ag/TiO2) indicates that silver loading is capable of inhibiting phase transition. Moreover, the result of UV visible analysis shows that the addition of silver cause no change on the band gap energy of TiO2. From TEM and SEM micrographs, the grain size of TiO2 at 500℃ is approximately 15~20nm. however, the grain size of Ag/TiO2 at the same temperature is approximately 10~15nm. Therefore, it is understood that silver loading inhibits the growth of TiO2 crystal size. The specific surface area of 44.714m2/g for TiO2 was determined from the BET analysis, the result reveals that an applicable amount of silver loading will increase specific surface area, but in excess it will decrease specific surface area. Thus 2%Ag/TiO2 is preferred which gives the best specific surface areas of 63.24m2/g. The solid-liquid phase photocatalytic reaction of nano-composite 2%Ag/TiO2 photocatalyst under UV light exposure for 420 min demonstrated nearly 90% degradation of methyl blue. Under a similar condition the solid-gas phase photocatalytic reaction of nano-composite 2%Ag/TiO2 photocatalyst was exposed for 240 min and demonstrated nearly 92% degradation of acetaldehyde. On anti-bacterial test it was found that 2%Ag/TiO2 nano-composite material have good anti-bacterial properties. From all of the test results, it is clear that the silver loading TiO2 is able to increase the photocatalytic activity and have good anti-bacterial properties.