Дисертації з теми "Nano Silver and Silver Ions"
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1
Das, Dipayan. "Application of nano silver and silver ions in preservation of mulberry leaves and their utilization in silkworm rearing system." Thesis, University of North Bengal, 2021. http://ir.nbu.ac.in/handle/123456789/4753.
Повний текст джерела
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Das, Dipayan. "Application of nano silver and silver ions in preservation of mulberry leaves and their utilization in silkworm rearing system." Thesis, University of North Bengal, 2021. http://ir.nbu.ac.in/handle/123456789/4752.
Повний текст джерела
3
Dhoubhadel, Mangal S. "Synthesis and Characterization of Ion Beam Assisted Silver Nanosystems in Silicon Based Materials for Enhanced Photocurrent Collection Efficiency." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc799502/.
Повний текст джерелаАнотація:
In recent years a great deal of interest has been focused on the synthesis of transitional metal (e.g. Ag, Cu, Fe, Au) nanosystems at the surface to sub-surface regions of Si and SiO2 matrices for fundamental understanding of their structures as well as for development of technological applications with enhanced electronic and optical properties. The applications of the metal nanoparticle or nanocluster (NC) systems range from plasmonics, photovoltaic devices, medical, and biosensors. In all of these applications; the size, shape and distribution of the metallic NCs in the silicon matrix play a key role. Low energy ion implantation followed by thermal annealing (in vacuum or gas environment) is one of the most suitable methods for synthesis of NCs at near surfaces to buried layers below the surfaces of the substrates. This technique can provide control over depth and concentration of the implanted ions in the host matrix. The implanted low energy metal ions initially amorphizes the Si substrates while being distributed at a shallow depth near the substrate surface. When subject to thermal annealing, the implanted ions agglomerate to form clusters of different sizes at different depths depending upon the fluence. However, for the heavier ions implanted with high fluences (~1×1016 - 1×1017 atoms/cm2), there lies challenges for accurately predicting the distribution of the implanted ions due to sputtering of the surface as well as redistribution of the implants within the host matrix. In this dissertation, we report the investigation of the saturation of the concentration of the implanted ion species in the depth profiles with low energies (< 80 keV) metal ions (Ag and Au) in Si (100), while studying the dynamic changes during the ion implantation. Multiple low energies (30-80 keV) Ag ions with different fluences were sequentially implanted into commercially available Si wafers in order to facilitate the formation of Ag NCs with a wide ion distributions range. The light absorption profile according to different sizes of NCs at the near-surface layers in Si were investigated. We have investigated the formation of Ag NCs in the Si matrix as a function of implantation and thermal annealing parameters. The absorbance of light is increased in Ag implanted Si with a significant increase in the current collection in I-V (current-voltage) photo switching measurements. The experimental photovoltaic cells fabricated with the Ag implanted Si samples were optically characterized under AM (air mass) 1.5 solar radiation conditions (~1.0 kW/m2). An enhancement in the charge collection were measured in the annealed samples, where prominent Ag NCs were formed in the Si matrix compared to the as-implanted samples with the amorphous layer. The characterization techniques such as Rutherford Backscattering Spectroscopy, XPS-depth profiling, transmission electron microscopy, optical absorption, and I-V (current-voltage) photo switching measurements were employed to understand the underlying science in the observed properties. The results of these investigations are discussed in this research.
4
Zhang, Li 1973. "Shockwave consolidation of nano silver powder into bulk nano structured silver." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100238.
Повний текст джерелаАнотація:
Bulk nanostructured silver components were fabricated from nano-sized powder using a shockwave consolidation technique. The grain size evolution during compaction, the mechanical properties of the bulk components, and the effect of surface finish on the mechanical behavior were studied. X-Ray diffraction, transmission electron microscopy (TEM), atomic force microscopy (AFM), microhardness, compression testing and shear punch testing at room temperature were used to characterize the materials. Upon consolidation, the average grain size calculated from image analysis of the TEM micrographs was 49+/-22 nm, showing the feasibility of maintaining a nanostructure upon dynamic consolidation. The hardness of the bulk nanostructured components was constant across the diameter with an average of 83+/-1 HV. Compression results showed strength about 390+/-10 MPa and ductility of 23+/-2%, which is well above strength level obtainable from strain hardened Ag components. The AFM results show that samples possessing a surface roughness of 267 nm exhibited a brittle behavior and a reduction in strength of 35% when compared to the smoother surfaces. Dimples were observed for the samples exhibiting plasticity, while an intergranular pattern was identified for the brittle materials. Fracture toughness of 0.2 MPa m was calculated, which confirms the strong relationship between fracture toughness and defects observed in nanomaterials.
5
Singh, Deirdre Mary. "Electroanalysis of chloride, bromide and silver ions." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363540.
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Toh, Her Shuang. "Electrochemistry of silver nanoparticles." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:7b9c8a2f-6599-446e-a0b3-cb33ca39e476.
Повний текст джерелаАнотація:
This thesis presents findings realising two main objectives. The first aim is to investigate the electrochemical detection of nanomaterials with an emphasis on silver nanoparticles. The second goal is to employ silver nanoparticles in electroanalysis to aid in the detection of other analytes. First, the detection of silver nanoparticles was demostrated through two different electrochemical methods, stripping voltammetry and 'nano-impacts'. For stripping voltammetry, the potential of metallic nanoparticles oxidation was quantified by various new analytical expressions for peak potential. For the novel method of 'nano-impacts', individual silver nanoparticles were successfully detected in an optically opaque suspension. Then, a comparison between the two techniques was achieved via the oxidation of silver nanoparticles with different capping agents. Strong capping agent effects was found for stripping voltammetry and one may markedly underestimate the amount of silver nanoparticle present on the electrode surface. The electrochemical sizing of nanoparticles via 'nano-impacts' remained unaffected by the capping agent effect. Amidst the study on the various types of capping agent, it was discovered that cetyltrimethylammonium bromide (CTAB) is electroactive due to the oxidation of its bromide content. This inspired the use of 'nano-impacts' to detect the presence of large CTAB micelles which self-assembled at concentrations above the critical micelle concentration. Next, various types of silver nanoparticles were applied to different electroanalytical systems to aid in the measurement of other analytes. (a) Small silver nuclei, remaining after the oxidative stripping of an electrode modified by silver nanoparticle suspension drop casting, allowed subsequent signal enhancement (at least a factor of three) in anodic stripping voltammetry of silver ions. (b) The thermodynamic favourable formation of silver halide complexes allowed the silver nanoparticle modified electrode to analyse the halide content of a solution. Hence, a proof-of-concept for an electrochemical sensor based on silver nanoparticle modified electrode for chloride ions was established. This might be applied to the pre-screening of cystic fibrosis, a genetic disease detrimental to many infants' lives. (c) Another key halide in human body, iodide ions, was also measured using a related concept. The level of iodide ions in synthetic human urine was determined. Last, the strong affinity of silver to thiol groups also warranted a study devoted to their interaction through electrochemical and spectroscopic measurements. It was found that there is no general mechanism for silver-thiol interaction and each thiol must be treated as a separate entity.
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Kanungo, Jyotirmayee. "Optical characterization of silver nano-wire metamaterials." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557635.
Повний текст джерелаАнотація:
Silver nanowires with diameters of a few tens of nanometers have gained a lot interest recently. An array of such nanowires within a dielectric host matrix are considered as an indefinite anisotropic metamaterial. These metamaterials exhibit negative refraction due to hyperbolic dispersion characteristics for extraordinary waves. The overall purpose of this research is to study the optical characteristics of such an indefinite system. First, an analytical formula was developed which describes the image formation due to a plane parallel slab of such a metamaterial for light emanating from a point source. The results of this analytic flat lens equation were compared with two- dimensional (2D) full wave simulations. One of the objectives of this work was to fabricate such delicate nanostructures. This was achieved by nano-porous alumina templates obtained following the novel two step anodization procedure. Afterwards an electrochemical plating technique was applied to deposit silver into the nano-channels forming a silver nanowire array. The inter-wire distance was only 60 nm so the metamaterial is considered as an effective medium for visible and infrared (IR) light. The optical characteristics of such a system were studied using angular resolved transmission measurements. In particular, a thorough analysis of the transmitted light was applied to determine the principal effective dielectric constants in the visible and IR range. In addition the equifrequency surfaces of the ordinary and extraordinary waves were mapped experimentally in a wave vector diagram for the first time. A comparison of the experimental results with Maxwell-Garnett effective medium theory showed a very good agreement and confirmed the original prediction that the silver nanowire arrays can be described as uniaxial indefinite metamaterials within visible and IR region.
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Babaahmadi, V., M. Ghanbarajjeh, T. Toliyat, and M. Montazer. "Photochemical reduction of silver nitrate to nano silver using stannous chloride, ctab and daylight irradiation." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20633.
Повний текст джерелаАнотація:
Silver nanoparticles (NPs) were synthesized and stabilized by a simple method in
aqueous solution, by the reduction of silver nitrate with stannous chloride (SnCl2.2H2O)
and cetyl trimethyl ammonium bromide (CTAB)through day light irradiation. Thereby,
the silver nanoparticles were colloidally stabilized by CTAB as a surfactant. The synthesis
of silver NPs with different size were possible by changing the reaction conditions
such as reagent ratio. The silver NPs were characterized by Dynamic Light Scattering
(DLS) and UV-visible spectroscopy. A very strong plasmon resonance peak at 400-500
nm in the UV-visible spectra is a clear consequence of the silver NPs production. The
synthesized silver NPs showed good stability by using CTAB.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20633
9
Torres, Urquidy Oscar Hernando. "Copper Resistant Bacteria Better Tolerate Commercially Available Antimicrobial Treatments Based in Silver and Silver-Copper Ions." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202734.
Повний текст джерелаАнотація:
In the current study, the antibacterial efficacy of zeolites containing silver or copper ions or a combination of these metals was assessed against several diverse copper resistant (CuR) and copper sensitive (CuS) strains of clinically relevant bacterial species. CuR Pseudomonas putida was significantly reduced in comparison to the unamended zeolite control. Unexpectedly, a CuS P. putida strain with no reported metal resistance appeared to be more resistant to the zeolite containing either Ag or Ag/Cu than the CuR strain. Contrary to expectations, after three and six hours of exposure, the CuS Escherichia coli displayed significantly more resistance to the Ag/Cu and Cu treatments than the reportedly CuR E. coli. All three reportedly CuR strains of Salmonella enterica exhibited resistance to Cu and Ag, as well as to the combination of the two metals after three and six hours of exposure. The reductions observed after 24 hours for all three CuR strains with Cu alone were still statistically significant compared to that of the CuS S. enterica strain. In addition, two of the CuR strains were more resistant to silver after 24 hours of exposure, suggesting a shared resistance mechanism such a copper efflux pump that also removes silver ions from the cell. Both the CuR and CuS strains of E. faecium were highly resistant to all of the treatments. In general, after comparison of all the resistances with all the treatments, E. faecium was the most resistant species, P. putida was the least resistant species, and the Salmonella strains were more resistant than E. coli in most cases.
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Rawson, C. Josephine. "Investigations of novel receptors for binding and sensing silver ions." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362120.
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11
Joo, Sung Chul. "Adhesion mechanisms of nano-particle silver to electronics packaging materials." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31730.
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Hu, Sijia. "Synthesis and Applications of Silver and Palladium Nano Metal Foams." Thesis, University of Missouri - Columbia, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13850738.
Повний текст джерелаАнотація:
Nanoporous metal foams (NMFs), a relatively new class of materials with low– density, high surface area and conductivity, have been studied recently in nano science. These materials can be engineered to benefit many fields and promise to enable new technologies in areas such as hydrogen storage, high power density battery, surface–enhanced Raman spectroscopy and supercapacitors. Herein a new developed method is presented to synthesis low–density, nanoporous metal foams of silver and palladium. This study mainly focuses on the synthesis process of NMFs of and it also provides some new applications that are useful in research and daily life.
Silver NMFs were produced by mixing silver nitrate mixed with ethylene glycol, ethanol, and a reducing agent, and heating at 150 W for 5min using a CEM microwave. Higher conversions for this process were obtained using either hydrazine or sodium borohydride as the acceptable reducing agent for this redox reaction. Palladium NMFs were synthesized in the same way in the condition of 150 °C with either hydrazine or sodium borohydride as the reducing agent.
Silver NMFs were applied in surface–enhanced Raman spectroscopy (SERS) as a substrate material. This material can enhance the detection of the rhodamine 6G (R6G), a model analyte. The limit of detection for rhodamine 6G was found to be 2 × 10–6 M with the help of this silver nanoporous structure. Palladium NMFs was found to degrade methyl orange (MO). An aqueous MO solution will turn nearly colorless after only 10 h of mixing with 0.03g of palladium NMFs at room temperature under dark condition. Different concentrations of MO solution were also studied to compare the reaction rates. This application is applicable to the treatment of liquid waste and water purification and is thus conductive to improving the environment.
13
Lei, Guangyin. "Synthesis of Nano-Silver Colloids and Their Anti-Microbial Effects." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31915.
Повний текст джерелаАнотація:
The antimicrobial effects of silver nanoparticles were studied. Silver nanoparticles were synthesized through wet chemistry method, and were dispersed in aqueous suspension. With nanoscale silica particles served as heterogeneous nucleation sites, silver nanoparticles were formed anchoring on the silica surface. Suspensions were found to be stable at high silver concentrations as well as over a broad pH range. By varying the processing conditions, diameter of the silver nanoparticles could be controlled between ~2 nm to ~25 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to reveal the formation and the corresponding morphology of the silver-silica coupling nanoparticles. Ultra-violet visible (UV-vis) scanning spectrophotometer was used to detecting the distinct absorption spectrum of silver nanoparticles. The antimicrobial activities of these silver-silica coupling nanoparticles were investigated. E. coli and S aureus were used as representatives of Gram-negative and Gram-positive bacteria, respectively. Bacteriological tests showed either bacterial growth inhibition or cell death occurred, corresponding to different concentrations of silver nanoparticles and the type of bacteria that were testing on. Fluorescent microscopic images were also provided to confirm the bacterial viability after several hoursâ treatment with silver nanoparticles.Master of Science
14
Kaganovskii, Yuri, Andrey A. Lipovskii, Emma Mogilko, Valentina Zhurikhina, and Michael Rosenbluh. "Kinetics of bulk nano-clustering in silver-doped glasses during reactive hydrogen diffusion: Kinetics of bulk nano-clustering in silver-doped glasses duringreactive hydrogen diffusion." Diffusion fundamentals 6 (2007) 42, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A13168.
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15
Landeen, Lee Kevin 1965. "Inactivation of Legionella pneumophila by copper-silver ions and free chlorine." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276997.
Повний текст джерелаАнотація:
Water disinfection systems utilizing electrolytically generated copper:silver ions (200:20 to 400:40 ug/L) and low levels of free chlorine (0.1 to 0.4 mg/L) were evaluated at room (21-23°C) and elevated (39-40°C) temperatures in filtered well water (pH 7.3) for their efficacy in inactivating Legionella pneumophila (ATCC 33155). A contact time of 24 hr was necessary for copper:silver (400:40 ug/L) to achieve a 3 log₁₀ reduction in bacterial numbers at room temperature. As the copper:silver concentration increased to 800:80 ug/L (K = 7.50 x 10⁻³ log₁₀ reduction/min), the inactivation rate significantly (p ≤ 0.05) increased. In water systems at room temperature with and without copper:silver (400:40 ug/L), the inactivation rates significantly increased as the free chlorine concentration increased from 0.1 mg/L (K = 0.397 log₁₀ reduction/min) to 0.4 mg/L (K = 1.047 log₁₀ reduction/min). All disinfection systems, regardless of temperature or free chlorine concentration, showed increased inactivation rates when 400:40 ug/L copper:silver was added; however, this trend was significant only at 0.4 mg/L free chlorine.
16
Chiou, Ipeng 1957. "Inactivation of Listeria monocytogenes by copper, silver ions and free chlorine." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277992.
Повний текст джерелаАнотація:
The antibacterial effect of electrolytically generated copper and silver separately and combined with free chlorine on Listeria monocytogenes was evaluated in filtered well water (FWW) and autoclaved dairy process water (ADPW). The inactivation rate (k = log10 reduction/minute) was determined. Slow bactericidal effects were observed in both FWW and ADPW after exposure to 400:40 or 800:80 mug/L copper and silver compared to 0.15 mg/L chlorine. At least five hours of exposure was required for a 6 log10 reduction in the bacterial numbers with copper and silver; however, with chlorine, the exposure time was reduced to less than one minute for the FWW. Addition of 0.15 mg/L chlorine to water containing copper and silver resulted in a significantly enhanced inactivation rate as compared to chlorine alone in both FWW and ADPW. In ADPW, chlorine with copper (400, 800 mug/L) resulted in an increased k value compared to chlorine alone and copper alone.
17
Bayat, M., and M. Khatibzadeh. "A Review On Green Methods for Synthesis of Silver Nano Particles." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35238.
Повний текст джерелаАнотація:
Metal nano particles are one of the most attractive aspects of nano materials in recent years. The reason
for this growing attraction is because of their special physical and chemical properties, which are more enhanced
from bulk material. Hence they find wide application in various fields like catalysis, photonics, optoelectronics,
information storage, antibacterial applications, etc. While considering metal nano particles,
electrical conductivity is one of the most important properties that can be used for humans’ benefit and
should be enhanced. Silver nano particles can be used in the electronics industry as conductive fillers because
of their unique properties such as high electrical and thermal conductivity, high resistance to oxidation.
It is impressive that eco friendly methods are being developed for synthesizing these nano particles,
using different kinds of plant extracts and water soluble component as capping agents, which results in different
forms of particle morphologies.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35238
18
Barton, Peter G. "Fabrication of Conductive Nanostructures by Femtosecond Laser Induced Reduction of Silver Ions." Thesis, Purdue University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10287501.
Повний текст джерелаАнотація:
Nanofabrication through multiphoton absorption has generated considerable interest because of its unique ability to generate 2D and 3D structures in a single laser-direct-write step as well as its ability to generate feature sizes well below the diffraction limited laser spot size. The majority of multiphoton fabrication has been used to create 3D structures of photopolymers which have applications in a wide variety of fields, but require additional post-processing steps to fabricate conductive structures. It has been shown that metal ions can also undergo multiphoton absorption, which reduces the metal ions to stable atoms/nanoparticles which are formed at the laser focal point. When the focus is located at the substrate surface, the reduced metal is deposited on the surface, which allows arbitrary 2D patterning as well as building up 3D structures from this first layer. Samples containing the metal ions can be prepared either in a liquid solution, or in a polymer film. The polymer film approach has the benefit of added support for the 3D metallic structures; however it is difficult to remove the polymer after fabrication to leave a free standing metallic structure. With the ion solution method, free standing metallic structures can be fabricated but need to be able to withstand surface tension forces when the remaining unexposed solution is washed away.
So far, silver nanowires with resistivity on the order of bulk silver have been fabricated, as well as a few small 3D structures. This research focuses on the surfactant assisted multiphoton reduction of silver ions in a liquid solution. The experimental setup consists of a Coherent Micra 10 Ultrafast laser with 30fs pulse length, 80MHz repetition rate, and a wavelength centered at 800nm. This beam is focused into the sample using a 100x objective with a N.A. of 1.49. Silver structures such as nanowires and grid patterns have been produced with minimum linewidth of 180nm. Silver nanowires with resistivity down to 6x bulk silver have been fabricated. Three-dimensional structures have also been fabricated with up to a 10µm height at a thickness of 500nm. This method can fabricate structures with the possible applications in plasmonic metamaterials, photonic crystals, MEMS/NEMS and micro/nanocircuitry.
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Cobbs, Ashley L. "Detection of Barium and Strontium Ions in Water Utilizing Functionalized Silver Nanoparticles." Ohio University Honors Tutorial College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1588098171596986.
Повний текст джерела
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Davies, K. M. "Effect of silver ions on gene expression during ripening and senescence in tomato." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233642.
Повний текст джерела
21
Kaganovskii, Yuri, Andrey A. Lipovskii, Emma Mogilko, Valentina Zhurikhina, and Michael Rosenbluh. "Kinetics of bulk nano-clustering in silver-doped glasses during reactive hydrogen diffusion." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193695.
Повний текст джерела
22
McCoppin, Jared Ray. "FABRICATION AND MASS TRANSPORT ANALYSIS OF TAPE CAST NANO-SILVER HIGH TEMPERATURE SOLDER." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1389285958.
Повний текст джерела
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Mirmohammadi, Seyed Aliakbar. "Study of Heat Transfer Performance of Silver Nanofluid at Nano- and Macro-Scale." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20796.
Повний текст джерелаАнотація:
Nanoscale solid particles dispersed in a host fluid are called nanofluids, which have attracted a vast attention in recent decades. Despite the diverse range of studies accomplished on nanofluids, there are still some secrets about them, which should be revealed by further in-depth studies. Hence, the present dissertation focuses on some important parameters that can affect the thermal performance of the nanofluids. Initially, this thesis presents a new data processing method for calculating more reliable thermophysical properties of liquids using Green-Kubo Method based molecular dynamics (MD) simulation. Equilibrium molecular dynamics simulation of water is first performed using three common water models. A new approach for analysing the simulation data is then developed to obtain statistically meaningful thermophysical properties such as thermal conductivity and viscosity. The proposed approach can ensure the repeatability and reliability of the calculated thermophysical properties of the liquid. Then, a guideline is developed that can suggest an appropriate simulation box size for a target standard deviation at different temperatures and water models. Several numerical and theoretical models have been proposed to predict the thermophysical behaviour of the nanofluids. However, most of these models were not able to predict accurately the thermal conductivity and viscosity for a variety of particle shapes or sizes. In the present paper, using the Green-Kubo Method based molecular dynamics simulations, new correlations for predicting the thermophysical properties of nanofluids are developed based on the particle shape, concentration, and fluid temperature. Silver nanofluids with various nanoparticle shapes including sphere, cube, cylinder and rectangular prisms were under investigation. The relative thermal conductivity and relative viscosity predicted by the proposed correlations are within a mean deviation of 2% and 5%, respectively, as compared with the experimental results from this study and available literature. The proposed correlations will be useful tools for engineers in designing the nanofluid for different applications. Hydraulic and thermal (hydrothermal) analysis of the silver nanofluid has been also investigated in this study. This is an important matter in thermal applications where working fluid is in motion. Two main parameters of the nanofluid flow, namely heat transfer coefficient and pressure drop in a double pipe heat exchanger are investigated using computational fluid dynamics (CFD). The results are validated against available experimental data in the literature. Finally, two correlations are developed for Nu number and friction factor of the nanofluids with different particle shapes, volume concentrations, Prandtl numbers, and flow rates in laminar regime.
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Ha, Hung M. "Micro- and Nano-Scale Corrosion in Iron-Based Bulk Metallic Glass Sam 1651 and Silver-cored MP35N Lt Composite." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1260391940.
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Damm, Josefin. "Silver i luktfria kläder : en stinkande lösning." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20820.
Повний текст джерелаАнотація:
Genom ökad användning på träningskläder har antibakteriella behandlingar blivit allt vanligare för den allmänna konsumenten. Dessa plagg marknadsförs ofta som antibakte-riella eller luktfria, men det som inte framgår är vilka ämnen som används för att uppnå den luktfria effekten. Vanligt förekommande är de behandlingar som är baserade på oorganiska silversalter. Medan leverantörerna av dessa produkter argumenterar för, argumenterar många miljövetare och forskare på bakterier emot antibakteriella produk-ter då dessa kan ha en skadlig inverkan på vår miljö och hälsa. Rapporten syftar till att ge större kunskap kring miljö- och hälsopåverkan vid användandet av textiler behandlade med silversalter samt till att analysera konsumenters inställning till antibakteriella kläder samt deras användar- och tvättvanor för träningskläder. Rapporten söker svar på om fördelarna med dessa silversaltbaserade antibakteriella behandlingar överväger nackde-larna. Insamlad teori inom området har sammanställts för att sedan testas mot empirin i form av intervjuer, enkätundersökning och användartest. De antibakteriella behandling-arna verkar oftast genom controlled-release principen vilken innebär att tillförsel av fukt krävs för att de verksamma antibakteriella ämnena ska aktiveras och förgöra eller hämma bakterietillväxten på tyget. Tester har visat att varje gång ett behandlat plagg tvättas läcker en del av de bakteriedödande silverjonerna ut i vårt allmänna avlopp och en del hamnar på övriga textilier i tvättmaskinen. En del av silverjonerna förenar sig i avloppsvattnet med svaveljoner och bildar den svårlösliga föreningen silversulfid. Silver i jonform är mycket giftigt för vattenlevande organismer och kan orsaka skadliga lång-tidseffekter på vattenmiljö och lätt bioackumuleras. Forskare har undersökt hur användaren av plagg behandlade med silverjoner påverkas. De drar som slutsats av studien att hudens naturliga bakterieflora och mikroklimat förblir nästintill opåverkade och klassar därför den antibakteriella textilen som användarsäker. Ytterligare forskning har dock visat att bakterier har förmåga att utveckla resistens mot silver på samma sätt som mot antibiotika. Ökad användning av silver i konsumentprodukter skulle därför kunna bidra till en ökad spridning av antibiotikaresistens. Ett säljargument som används av flera marknadsaktörer är den minskade energi- och vattenförbrukningen i användar-fasen, då konsumenten inte behöver tvätta ett antibakteriellt plagg lika ofta som ett obehandlat. För att ta reda på om argumentet stöds i praktiken genomfördes en enkät-undersökning. Utifrån enkätsvaren framgår det tydligt att dessa behandlingar varken påverkar användar- eller tvättvanor och inte heller är något som efterfrågas av konsu-menten i första hand vid inköp av träningskläder. Ett användartest genomfördes för att undersöka om den antibakteriella behandlingen gör någon märkbar skillnad för använ-daren, genom att minska den dåliga odören på plagget. Slutsatsen drogs att det inte är någon markant skillnad på ett behandlat respektive obehandlat träningsplagg. Baserat på de teoretiska fakta om silverjoners negativa påverkan på miljö och människors hälsa, främst i form av risk för utveckling av resistenta bakterier, samt grundat på de empiriska resultaten från användartest och enkät så dras slutsatsen att fördelarna inte överväger nackdelarna med dessa behandlingar och det rekommenderas starkt att inte använda någon antibakteriell behandling innehållande silversalter.Through increased use on sport clothing, antibacterial treatments have become increas-ingly common for the general consumer. These are often marketed as antibacterial and odor-free, but what is not clear is what kind of substances that are used to achieve the odor-free effect. Usually these are based on inorganic silver salts. While suppliers of antibacterial products advocates these, many scientists in environmental science and bacteriological research discourage to the use as they may have an adverse impact on our environment and health. The report aims to provide greater knowledge about environmental and health impacts from the use of fabrics treated with silver salts, and to analyze consumer’s attitude to antibacterial clothes and their patterns of behavior and laundry habits for sport clothes. The report seeks to answer if the benefits of these silver salt-based antibacterial treatments outweigh the disadvantages. Collected theory in the field was compiled and then tested against empirical data in the form of inter-views, survey and consumer test. Laboratory tests have shown that each time a treated garment is washed some of the antimicrobial silver ions leaks into our public sewage and some sticks to other textiles in the washing machine. Some of the silver ions combine in the wastewater with sulfur ions to form the insoluble compound silver sulfide. Silver in ionic form is highly toxic to aquatic organisms and can cause long term adverse effects on aquatic life and easily bioaccumulate. Researchers have examined how users of garments treated with silver ions are affected. They draw as conclusion from the study that the skin's natural bacterial flora and micro-climate will remain unaffected and, therefore, categorizes the antibacterial fabrics as safe for the consumer. Further re-search has shown that bacteria have the ability to develop resistance to silver in the same way as to antibiotics. Increased use of silver in consumer products could therefore contribute to a greater spread of antibiotic resistance. A common sales argument used by many market participants is the reduced energy and water consumption in the con-sumer phase, where consumers do not need to wash antibacterial clothes as often as untreated. To find out if the argument is supported in practice, a survey was conducted. Based on the survey responses, it is clear that these treatments do not affect the con-sumer’s behavior in use or washing habits and is not demanded primarily by the consumer for the purchase of sport clothes. A consumer test was conducted to investi-gate whether the antibacterial treatment make any noticeable difference to the user, by reducing the bad odor in the clothes. It was concluded that there is no marked differ-ence in the treated and untreated sport clothes. Based on the theoretical facts about silver ions negative impact on the environment and human health, especially involving the risk of development of resistant bacteria, and based on the empirical results from consumer test and survey, it is concluded that the benefits of silver salt-based treat-ments do not outweigh the disadvantages and it is highly recommended to not use any antibacterial treatment containing silver salts.Program: Textil produktutveckling med entreprenörs- och affärsinriktning
26
Do, Dang Giap, Thi Kim Thuy Dang, Thi Huyen Trang Nguyen, Thi Duoc Nguyen, Trong Tuan Tran, and Duc Hieu Duong. "Effects of nano silver on the growth of banana (Musa spp.) cultured in vitro." Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A33343.
Повний текст джерелаАнотація:
Nano silver has positive effects on the growth and development of in vitro plants. In this study, shoots of in vitro banana with 1 cm in length were cut off the tip which was cultured in Murashige and Skoog (MS) medium supplemented with 30 g.L-1 sucrose, 15% coconut water (v/v), 5 mg. L-1 6-Benzyladenine (BA), 8 g.L-1 agar and nano silver (1, 3, 5, 7 ppm). After twenty days cultured, shoots in the medium supplemented with 1 ppm nano silver have grown well with 8.4 times multiplication and total chlorophyll content (2.05 mg.g-1), three-fold higher than in the control experiment. All new shoot samples were cultivated in a new medium with same component and supplemented with 1 mg.L-1 active charcoal to study root formation. The results showed that the best medium for root development was the one with 3 ppm nano silver. In this treatment, the height of shoots, number of leaves, number of roots, root length, fresh weight, dry weight and total chlorophyll content were 2.90 cm, 4.40 leaves per explant, 7.10 roots per explant, 7.7 cm per explant, 1.47 g per explant, 0.136 g and 3.17 mg.g-1, respectively. In vitro healthy seedlings with equal size were grown in nurseries. Different concentrations of nano silver (5, 10, 15 ppm) were sprayed on once a week. After 30 days, the highest quality result was observed at concentration 5 ppm with shoot of 4.86 cm in length, 5.20 leaves per shoot, 4.60 roots per explant, root of 4.87 cm in length and 3.07 g per explant in fresh weight.Nano bạc có tác động tích cực lên quá trình sinh trưởng và phát triển của một số loài thực vật nuôi cấy in vitro. Trong nghiên cứu này, chồi non in vitro có chiều cao 1 cm đã cắt bỏ đỉnh được nuôi cấy trên môi trường MS có bổ sung 30 g/L đường, 15% nước dừa (v/v), 5 mg/L BA, 8 g/L agar và nano bạc ở nồng độ 1, 3, 5, 7 ppm. Sau 20 ngày nuôi cấy, mẫu cấy phát triển tốt trên môi trường bổ sung nano bạc nồng độ 1 ppm với hệ số nhân chồi 8,4 lần, hàm lượng chlorophyll tổng số đạt 2,05 mg/g, cao gấp ba lần so với mẫu đối chứng. Mẫu cấy được chuyền sang môi trường mới có thành phần tương tự và bổ sung thêm 1 mg/L than hoạt tính để khảo sát sự tạo rễ. Kết quả cho thấy mẫu cấy trên môi trường có nồng độ nano bạc 3 ppm phát triển tốt nhất với chiều cao cây 2,90 cm/mẫu; số lá 4,40/ mẫu; số rễ 7,10/ mẫu; chiều dài rễ 7,7 cm/mẫu; khối lượng tươi 1,47 g/mẫu, khối lượng khô 0,136 g/mẫu và hàm lượng chlorophyll tổng đạt 3,17 mg/g. Những cây con in vitro phát triển tốt được trồng ngoài vườn ươm. Các dung dịch nano bạc có nồng độ 5, 10, 15 ppm được dùng để phun lên cây 1 lần/tuần. Sau 30 ngày, kết quả cao nhất ghi nhận ở dung dịch có nồng độ 5 ppm với chiều cao chồi đạt 4,86 cm, 5,20 lá/chồi, 4,60 rễ/mẫu, chiều dài rễ đạt 4,87 cm và khối lượng tươi đạt 3,07 g/mẫu.
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Wu, Ting-Hsien, and 吳侹賢. "Research Sterilization Effect of Nano Silver Ion." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/81614527895882733120.
Повний текст джерелаАнотація:
碩士吳鳳技術學院
光機電暨材料研究所
97
Kaolin contains essential zeolite components SiO2 and Al2O3. This study synthesized A-type zeolite by using kaolin as a raw material. The kaolin was activated by transforming it from crystalline to amorphous state, then the denatured kaolin was added to an alkaline solution, transformed it to A-type zeolite. The ion exchange method was used for preparing Ag-carrying zeolite antimicrobial. A plate count method was used for the antibacterial test after the antimicrobial has been added to an incubation solution and incubated for 72hr. The antibacterial rate show that 3 % of antimicrobial is enough to kill almost all the bacteria.
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Palui, Arnab. "Investigation of ion dynamics in mixed network former glasses." Thesis, 2019. http://hdl.handle.net/10821/8246.
Повний текст джерелаАнотація:
The work of this thesis is mainly based on the study of structure and ion dynamics of
several new ion conducting glasses and to correlate the macroscopic ion transport
properties to the glass network structure and the microscopic lengths. The organization
of the thesis is as follows
Chapter 1 of this thesis deals with the literature review in the field of glasses. A
brief introduction to glasses is presented and their exotic features are discussed. The
network structures of different type of glasses are briefly discussed. Several theoretical
models and concepts used to explain and understand the ion dynamics are pointed out.
Finally the scope of the thesis is presented.
In chapter 2 a brief description of the preparation technique of glasses and glassnanocomposites
and various experimental methods used to characterize them are
presented. In the initial part of the chapter the structural characterization such as
density, x-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission
electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and
Fourier transform infrared (FTIR) spectroscopy techniques are discussed. In the later
part, electrical characterization techniques used to study the ion dynamics are presented.
In Chapter 3 the structural and electrical properties of xAgI-(1-x)(0.3Ag2O-
0.7(0.5SeO2-0.5MoO3)) glasses have been investigated. The structural characterizations of
these glasses have been carried out using XRD, FTIR spectroscopy etc. and the thermal
study has been done using Differential Scanning Calorimeter. The Ag+ ion dynamics in
the glasses has been investigated in a broad frequency range from 10Hz – 2MHz and in
wide temperature range. The dc conductivity and the microscopic lengths obtained from
the linear response theory have been correlated to the glass network structure.
Chapter 4 deals with the study of mixed former effect and dynamics of Ag+ ions
of xAgI-(1-x)(0.3Ag2O-0.7(ySeO2-(1-y)MoO3)) glasses. The glass formation has been
confirmed using XRD. The thermodynamic properties of these glasses have been
explored using DSC. The modification of the glass network structure has been analyzed
using deconvolution of the FTIR spectra. The ionic conductivity of these glasses has been
compared to that of the undoped silver selenomolybdate glasses. The study of relaxation dynamics in these glasses has been performed in the framework of the conductivity and the electric modulus formalism. The characteristic lengths obtained from the
conductivity and dielectric spectra have been correlated to the modification of the glass
network structure.
In chapter 5 the study of mixed former effect and ion dynamics in silver ion
conducting mixed network former glasses of composition yAg2O-(1-y)(xSeO2-(1-y))TeO2
are presented in wide composition and temperature ranges. The glass network
structures and structural modification depending on composition has been investigated
using FTIR spectroscopy. The ion dynamics in these mixed former glasses has been
studied using the conductivity formalism as a function of frequency and temperature.
The correlation of ion transport properties to the microscopic length scales and the glass
network structure has been established.
In chapter 6 the Ag+ ion dynamics in xAgI-(1-x)(yAg2O-(1-y)(0.5SeO2-O.5TeO2))
mixed network former glasses for different modifier content is presented. The thermal
properties of these glasses have been studied using DSC. The relative concentrations of
different network structural units have been determined from the de-convolution of the
FTIR spectra. The ac conductivity has been investigated taking the contribution of the
electrode-sample interface. The length scales of ion dynamics, such as characteristic
mean square displacement and spatial extent of sub-diffusive motion of silver ions have been determined from the ac conductivity and dielectric spectra respectively in the framework of linear response theory. A direct correlation between the ion dynamics and the characteristic length scales and the glass network structure has been established for different compositions of the selenium-tellurite glasses. In Chapter 7 the summary of the thesis is presented. The possible future research in continuation of this work is also highlighted.Research was carried out under the supervision of Prof. Aswini Ghosh of Solid State Division under SPS [School of Physical Sciences]
Research was conducted under DST grant and IACS fellowship
29
Man-Yu, Lin, and 林滿玉. "Investigation of Silver Nano Structures." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/43538726543664996786.
Повний текст джерелаАнотація:
碩士國立清華大學
材料科學工程學系
91
The formation of silver metal nanodots including Ag@HT, Ag@DT and Ag@ODT nanodots has been investigated. By using a liquid-liquid two-phase method, the size of Ag@DT nanodots is close to 4 nm. The size of Ag@ODT nanodots is smaller with wider distribution. The size and size distribution of Ag@HT nanodots are even larger and wider, respectively. Two-dimensional ordered superlattices of the nanodots were formed on carbon films coated on transmission electron microscopy (TEM) copper grids by evaporating a drop of the dispersion in toluene. To fabricate self-assembled metal nanodots, some specifications must be met. First, the quantity of alkanethiol (0.15 ml of dodecanethiol) is important because it permits the non-aggregation of dots and the arrangement in ordered arrays. When Br was substituted by S, the organization in self-assembled arrays is improved. The link between dots is stronger with S so that the prevention of aggregation of nanodots is more effective. Second, the organic solvent (toluene) is selected to realize the rapid drying of the nanodots solution on the substrate. The drying must not be too fast or too slow because the evaporation rate determines the quality of the ordered structures. The silver nanodots were investigated by UV-visible absorption spectroscopy and TEM. A shift of the maximum absorption peak position of the UV-visible spectra occurred for different dot sizes. The results indicated that large thiol-capped silver nanodots led to a red shift in UV-visible absorption spectroscopy; small thiol-capped silver nanodots resulted in a blue shift. The TEM images show consistent results with that of the UV-visible spectra. In addition, the UV-visible spectra of the Ag@DT nanodot colloids obtained show that the system is more monodisperse than those of the Ag@HT and Ag@ODT nanodot colloids, and can remain stable for several weeks. Thermogravimetric analyses were carried out for Ag@HT, Ag@DT and Ag@ODT nanodots. The mass decrease started at about 140, 180, and 225℃ for Ag@HT, Ag@DT and Ag@ODT nanodots, respectively. The results indicate that the outer- shell with longer chain (as octadecyl-thiol) is thermally more stable than that of shorter chain (as hexyl-thiol). For Ag nanodots, grating peaks have been observed in the X-ray diffraction spectra. This behavior appears for multi-layer characterized by linear structures. Moreover, the first peak of diffraction can be used to estimate the distance between layers. Hexagonal networks were formed on carbon films and on Si(001). Solutions containing different concentrations of nanodots were developed to form networks. Good suspension capability, an appropriate concentration of silver nanodots and moisture content are essential to form superior networks. A simple method was used to synthesize silver disks. The rods and disks were found to form and grow to several micro-meters. The rods tend to orient with respect to each other by 60° or 120° if the rods are long enough (at least 500 nm). In addition, for silver disks to form, it seems advantageous to mix with DI water. Replacing ethanol with DI water altogether appears to improve the shapes of silver-disk. Furthermore, the reaction time is shorter than that of solvent with just ethanol.
30
Huang, Yung-Han, and 黃勇翰. "Preparation of Silver Nano-particles From the Reduction Processes of Silver Chloride." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/7n3qfc.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
材料科學與工程研究所
100
This study is to investigate the possibility and effect of using recycled silver chloride , adding to ammonium hydroxide by chemical reduction method at room temperature to prepare and generate metal nanoparticles with different concentrations of surfactant and reducing agent , so that discussing such as particle size, shape, optical properties, and so on. Preliminary to analysis and judge by the UV-visible spectrometer instrument, then particle size analysis, SEM, TEM and EDS to find and research the characteristic of the particles. Analysis showed that throw the UV-visible spectrometer, the concentration of the 0.05 mm and 0.1 mM precursors can not be generated to silver nano-particles. At the same precursor concentration, absorption strength is lower with high surfactant concentration. By the particle size analysis, the average particle size is larger with low reducing agent concentration under the other parameters fixed and larger with high surfactant concentration under the other parameters fixed. Through SEM images, the silver nano-particles prepared from chemical reduction processes are almost irregular-shaped, a few ball-shaped and bar-shaped. EDS analysis show there have naon-particles containing silver element. The nano-particles of B3C1 parameter are less aggregated but uniformly dispersed, and silver ingredient accounted is up to 95% and is the best parameter set.
31
Han, Ming-Yu, and 韓鳴宇. "The study of recovery silver Nano-particles from the scrap with conductive silver paste." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/n5yrcp.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
材料科學與工程研究所
101
According to the lack of noble metal resource becomes a serious problem now; recycle is a good way to get noble metal such as gold, silver, platinum and etc. In this study, we recycle silver resource from conductive silver paste which is the main conductor of electricity in the membrane of keyboard. In this research, we want to get silver nanoparticles from this membrane; chemical reduction is a cheap and easy method to get silver Nano-particles. After thermal treatment at 600℃, almost all polymers are removed. Add nitrate into the silver crap then the solution becomes silver nitrate. By using chemical precipitation method, this research can get the silver chloride precipitation from the reactant including silver nitrate and chloride. This study uses different molar concentration of Ag(NH3)2+, NaBH4 and CTAB to find a proper proportion preparing silver nanoparticles. This study analyses the final product by using XRD, SEM, UV-Vis, EDS, and ICP-AES. The XRD result shows that this research can successfully get silver nanoparticles with crystal structure from conductive silver paste. The result of UV-visible spectrometer shows that a characteristic absorbance peak around 400 nm in wavelength can be found. The particle size is around 70nm when the molar ratio of NaBH4 / Ag is 1.5 and the molar concentration of CTAB is 20mM. The conversion rate is above 99%.
32
Chang, Tieh-Ming, and 張鐵明. "FDTD simulation of nano imaging with silver nano rod structure." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/68127858152127808964.
Повний текст джерелаАнотація:
碩士國立臺灣大學
物理研究所
94
Silver nanorods have an excellent localization of the transmitted wave; especially the localized spot has a space below the bottom of the nanorods. In this dissertation, the near field distribution of silver nanorods is investigated. The numerical method knows as finite difference time domain (FDTD) is introduced into near field optics. The effects of various radius, lengths, gaps and separations of silver nanorod array are investigated. Results of the calculation provide a direct theoretical basis for the relation between the localization of surface Plasmon and the enhance of near field. The near field distribution of nano hexagonal rod, and the parallel nanorod array are studies systematically using our FDTD method. It is found that the image is highly dependent on the spacing and radius of nanorods. Results of single nanorod show similar near field distribution to an electrical dipole. Due to the boundary condition at the interface, the polarized incident wave enhance the field at boundary of the nanorod. The influence of nanorods on contrast is studied with FDTD method as well. Silver nanorods have an excellent effect on localizing the transmitted wave, especially, the enhancements below the bottom of the nanorods. In this dissertation, a systematic apparoach to studying the near-field distributions, from a single nanorod to an array of nanorods, is carried out. The three-dimensional finite difference time domain (3D FDTD) which is a well known and powerful numerical method is used to simulate the interactions of the optical waves with the silver nanorods. The near-field distribution of a single nanorod is similar to an electrical dipole. The effects of radius variation, lengths of nanorods, gaps and spacings in the silver nanorod array are investigated. It is found that the image formed from the transmitted wave is highly dependent on the spacing and radius of nanorods. According to the relation between the localization of surface plasmon and the enhancement of near field, the optimal criteria can be obtained in constructing optical nanolithographic sturcutures.
33
Su, Yu-Ting, and 蘇瑜婷. "Detection of Copper Ions Using Copper/Silver Nanoclusters." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/70890253207905955663.
Повний текст джерелаАнотація:
碩士國立臺灣大學
化學研究所
98
This thesis focuses on devoloping a simple and homogeneous fluorescence assay—comprising 3-mercaptopropionic acid (MPA) with DNA-Cu/Ag nanoclusters (NCs) in aqueous solution—for the detection of Cu2+ ions. The sensing mechanism is based on the suppression of MPA induced fluorescence quenching of the DNA-Cu/Ag NCs by Cu2+. MPA-induced fluorescence quenching is due to changes in the DNA conformation as a result of the interactions between MPA and Cu/Ag clusters. The MPA-induced fluorescence quenching followed a typical characteristic of a Stern-Volmer plot and followed a static quenching mechanism. The presence of Cu2+ resulted in the oxidation of MPA to form disulfide, leading to suppression of the MPA-induced fluorescence quenching. The fluorescence of the DNA-Cu/Ag NCs in the presence of MPA increased upon increasing the concentration of Cu2+ over the range 5-200 nM. The DNA-Cu/Ag NC probe provided the limit of detection at a signal-to-noise of 3 of 2.7 nM for Cu2+ ions, with high selectivity (at least 2300-folds over tested metal ions). The practicality of this approach has been validated by the analyses of Montana soil and water samples (3 replicate measurements), showing the potential of the probe for detection of Cu2+ ions in environmental samples.
34
Tseng, Kuo-Wei, and 曾國瑋. "Germicidal Effects of Nano Silver Filter on Bioaerosols." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52815746773307573783.
Повний текст джерелаАнотація:
碩士國立臺灣大學
環境工程學研究所
94
The study evaluates filtration efficiency and germicidal effects of nano silver filter on bioaerosols. The experiment used a Collison nebulizer was used to generate Escherichia coli (E. coli), Bacillus. Subtilis (B. subtilis), endospores, yeast cells of Candida famata (C. famata) var. flareri, and spores of Penicillum citrinum (P. citrinum) and in the experimental system. After loading process, the bioaerosols were washed out of the test filter and then cultivated for counting. The experimental factors are microorganism species, relative humidity (30, 50, 70%), loading time (5－90 min), decay time (0－180 min) and type of filter (nonwoven filter and Ag-coated filter). The experimental data revealed that filtration efficiency with nano silver filter of bioaerosols of E. coli, B. subtilis, C. famata, and P. citrinum at relative humidity of 50% were around 38.6, 29.9, 41.8, and 49.8% respectively. The germicidal effect of nano silver is E. coli > C. famata > B. subtilis > P. citrinum. The germicidal effect of E. coli is excellent (99%) when relative humidity is below 50 percent. Moreover, the nano silver filter has the better removal and germicidal efficiency in the high relative humidity (70%) for non-spore bioaerosols (E. coli and C. famata) than spore bioa erosols. The decay test showed that the survival rate decreased significant when E. coli and C. famata bioaerosols were intercepted on nano silver filter. In other words, we don’t need to worry that bioaerosols’ survival on nano silver filter.
35
Lin, ShinJie, and 林欣潔. "Fabrication of Nano-silver Antimicrobial Film by Entrapment." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/01430907289193011582.
Повний текст джерелаАнотація:
碩士輔仁大學
食品科學系
96
The aims of this study focused on fabrication of antimicrobial film used in active packaging by entrapping silver nanoparticles on surface modified polyolefin film. Low density polyethylene (LDPE), used as a vehicle for nano-Ag, was modified by UV/O3/TiO2 process. Subsequently, polyvinylpyrrolidone (PVP), a nano particle stabilizer, was then applied to the LDPE to form a matrix for silver nanoparticles produced through reduction of ions using ascorbic acid. Active packaging material was analyzed by FT–IR and contact angle for surface modification and degree of PVP attachment. Formation of polar functional groups (such as –C=O) was found on LDPE surface after 6 hr UV/O3/TiO2 treatment, and the contact angle of the polyolefin film was noticed decreasing from 105.04o to 84.86o. The amount of PVP incorporated on LDPE was determined by ATR-FTIR, and found the optimal PVP incorporation at 1% concentration for 3 hr incubation. Particle size distribution determined by Dynamic Laser Scattering analyzer (DLS) showed particles size distribution of PVP and PVP–Ag complex ranging 4–6 nm and 150–170 nm, respectively, this indicated the interaction between PVP and silver ions. Moreover, the sizes of PVP-Ag complex decreased to 70–90 nm after reduction. Surface image analyzed by AFM and SEM revealed 50-100 nm silver nanoparticles immobilized on the LDPE surface. Silver nanoparticles film demonstrated antimicrobial activity against Eschericia coli ATCC 8739, cell numbers were reduced from 104 to 102 cfu/ml in 24 hr, however, no significant antimicrobial activities against yeast (Saccharomyces cerevisiae) and spore forming bacteria (Bacillus substilits). In the repeated use test, active film showed effectively to inhibit the growth of E. coli, but yeast. Active packaging film of immobilized nano-Ag functions to suppress gram negative bacteria (E. coli), further studies of the effect of nano-Ag immobilized on film against microorganism, and the stability of immobilized nano-Ag are taken into account.
36
Chen, Yi-Chin, and 陳怡錦. "Preparation and Characterization of Nano-silver Doped Sericite." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/85768806828895545604.
Повний текст джерелаАнотація:
碩士中原大學
化學研究所
95
ABSTRACT In this study, we applied the natural sericite as the basic material. Because the sericite is native to Taiwan, and it has large aspect ratio and high cation exchange capacity. When aspect ratio is bigger than the cation exchange equivalent capacity, it indicates that the active groups per unit area are more. Therefore we the first purified and modified the sericite, then the silver ions were reduced to silver atom, and inserted into the interlayer of the basic material, as the organic/inorganic nanocomposites. We also discuss its conductive, antibacterial, and the thermal properties etc. Because of the modification of purified sericite is carried out by the silver mirror reaction (Electroless Plating or Chemical reduction method) and ion-exchange method, the silver ion is intercalated into the interlayer of the sericite which is inconductible with the cation exchange ions, then followed by the reduction reaction by applying the redcuing agents like glucose or NaBH4 etc, which cause the reduction of silver ion to silver atom. This made the sericite become conductive. We also added the modifier like Lonzaine CS, as the compatibilizers between sericite and the epoxy resin, it makes sericite - epoxy resin with remarkable conductive nanocomposites. In this work, there are some instruments are applied for the structure identification and thermal property measurement, such as XRD, TGA, ICP-AES, SEM, TEM and DMA. Experimental results show that the sericite - epoxy resin nanocomposites can be applied in the special painting, the seal material, anti-static electricity and against electromagnetic wave and so on in the future. In the antibacterial application, the conductive sericite provides the remarkable antibacterial effect, which can be used in the antibacterial product market in the future.
37
Chou, Meng-Tai, and 周孟泰. "Synthesis and AEM characterization of silver nano-belt." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/88583967179600490343.
Повний текст джерелаАнотація:
碩士國立東華大學
材料科學與工程學系
99
Without the addition of any capping agents, silver nano-belt arrays were successfully synthesized on top of ITO glass through the reduction/oxidation reactions in an aqueous silver nitrate solution using indium metal as the reduction agent. Depending on the processing variables, besides the nano-belts, pure silver products with different morphologies, including rod-like, wire-like, plate-like, as well as equiaxed particles with various shapes, were also obtained. The synthesized silver nano-belts are all elongated along the closed-packed <011>fcc direction, and bounded by two large faces parallel to {111}fcc and the two small edges consisting of {111}fcc and {100}fcc facets, as confirmed by TEM observations. Cross-section TEM observations further showed that multiple {111}fcc twin boundaries, oriented parallel to the belt faces and extending throughout the whole length of a belt, are always present within the synthesized nano-belts. Selected area electron diffraction study showed that the crystal domains across such twin boundaries usually do not follow the strict {111}fcc twin law, but have ~1 rotation deviation with respect the <011>fcc growth direction of nano-belts. This leaves only one true coherent close-packed <011>fcc direction on such twin boundaries, and therefore results into <011>fcc directional growth of silver nano-belts as reported here. The synthesized silver nano-belts were most likely grown from the multiple twinned nano-particles of < 10 nm, as observed in high resolution TEM, under low to medium Ag-supersaturation conditions.
38
Lai, Yen-An, and 賴彥安. "Photocatlytic Reaction in Heterostructured ZnO Nano-Particles／Silver Nano-Wires Composites." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/57249982853633315158.
Повний текст джерелаАнотація:
碩士中原大學
奈米科技碩士學位學程
103
Zinc oxide (ZnO) is one of the most popular semiconductor materials in recent years. In this study, we synthesized zinc oxide nano-particles (ZnO NPs) by the typical sol-gel method with ultrasonic treatment to avoid particle aggregation In the first part of this thesis, we discussed how the molecular weights (NW) of polyvinyl pyrrolidone (PVP), which was used as a protecting agent in the synthesis, affect the ZnO NPs size and the oxygen vacancies in ZnO structure. We characterized the ZnO NPs by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), photoluminescence (PL), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Raman spectroscopy, etc. Next, we chose PVP MW ~ 8K to synthesize the optimized ZnO NPs. Then we combined ZnO NPs and silver nano-wires (Ag NWs) into heterostructured nano-composites with a UV light treatment. In this step, we also characterized the samples by TEM, SEM, PL, UV-vis, EDS, XRD, etc. The last as well as main purpose of this thesis is to study the photo-catalysis reaction with our ZnO / Ag nano-composites. The degradation of the organic pollutant methyl blue (MB) was used to evaluate the photo-catalytic efficiency. We compared the photo-catalytic efficiency of the pure ZnO samples synthesized by different PVP molar weights and the ZnO/Ag nano-composites.
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Li, Hong-Rui, and 李泓瑞. "Preparation of micro/nano silver coordination complex fibers by microfluidic method and reduction to pure silver." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/p5hn8z.
Повний текст джерелаАнотація:
碩士國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
106
In this study, a microfluidic chip with microchannel was fabricated using acrylic (PMMA) as substrate and CO2laser engraving/cutting technique. Then, the silver coordination complex fibers was prepared by micro-fluid synthesis method, and finally the silver coordination compound fibers were reduced to pure silver particles using the nitric acid oxidation method. The use of CO2 laser engraving machine can not only accurately control the size of the microchannel, but also has the advantages of rapid preparation, simple process, repeatable and batch preparation of microfluidic chips. When too many reactants are accumulated in the microchannel, the microfluidic chips can be disassembled and cleaned to make the chips reusable, reducing the experimental cost and consumable. The micro/nano-silver complex fibers were prepared by using a simple microfluidic method to reduce silver nitrate (AgNO3) using L-cysteine as a reducing/protecting agent. The diameter of micro/nano-silver complex fibers were approximately 200 to 400 nm, and the length exceeded 10 μm confirmed by scanning electron microscopy (SEM). The -SH group belonging to L-cysteine was observed by Fourier infrared spectroscopy (FTIR), while the -SH group was not observed in the silver complex compound fiber, confirming the existence of Ag-S covalent bond. The prepared silver coordination complex fibers were added into dilute nitric acid solution, stirred, and filtered. The filtrate was added with dilute hydrochloric acid to precipitate, and the precipitate was collected and dried. The spherical particles identified as silver chloride with face-centered cubic structure by X-ray diffraction (XRD). The silver chloride particles were added to a solution of ammonia and hydazine hydrate solution for reduction. The product was identified by XRD as a face-centered cubic spherical silver metal (Fm3̅m, 225). This study can accurately and easily prepare microfluidic chips and effectively replace traditional methods for preparing microfluidic chips. The microfluidic method can effectively prepare silver coordination complex fibers by controlling the molar ratio, the flow rate and the pH, and can be reduced to metal silver particles by the nitric acid oxidation method.
40
Cheng, Tien-Hsin, and 鄭恬欣. "Antimicrobial Ability of Electrospun Nano-silver Incorporated Film and the Release of Silver in Food Simulants." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/9acm3c.
Повний текст джерелаАнотація:
碩士國立宜蘭大學
食品科學系碩士班
104
Silver nanoparticles (AgNPs) have a large surface area to-volume ratio, favoring interaction with microbial cell, and exhibtd excellent antimicrobial ability. However, the cytotoxicity induced by AgNPs was mediated through reactive oxygen species (ROS). Therefore, the control of AgNPs migration to foods is an important issue for AgNPs containing antimicrobialantimicrobial film. In this work, in situ synthesis of silver nanoparticles (AgNPs) was reducted from silver nitrate in the nylon6 solution and was then immobilized by electrospinning on polypropylene (PP) to form a AgNPs-nylon6/PP antimicrobial composite film. The structure of the electrospun fibers was studied by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The formation and crystallization patternsof AgNPs were investigated by UV/VIS spectrophotometer and X-ray diffraction (XRD), respectively. The antimicrobial properties of AgNPs-nylon6/PP films under various electrospun solution and operating parameters were investigated and the reduction in the release of silver nanoparticles in food stimulants was also evaluated. The results revealed that the color of nylon6 solution became yellow-green when AgNO3 was added, and its UV/VIS spectra exhibited an absorption band at 410 nm and 425 nm, which were typical surface plasmon polariton resonances of two forms of AgNPs presence. Formic acid/acetic acid ratio at 4:1 was the desirable in situ synthesis conditions for the preparation of silver nanoparticles. The beaded fibers were generated by electrospinning as the nylon6 concentration was lower than 18% because of its low viscosity. Homogeneous fiber networks were generated as nylon6 concentration was higher than 18% (viscosity ≥ 1298 cp). High specific surface area (15-19 m2/g) and 66-213 nm diameter of electrospun fibers were obtained. The 2-5 nm AgNPs, which were face-centered cubic crystal structure with (111) plane contribute to antimicrobial ability, were uniformly distributed on fibers. The 4% AgNPs-nylon6/PP composite (electrospun from 4% AgNO3 in nylon6 solution for 30 minutes) formed a 3 μm thickness electrospun coating and inhibited E. coli growth within 48 hrs and the accumulative release amount of silver ions reached 0.60 μg/mL after 48 hrs immersion in TSB. The accumulative release amount of silver ions reached 0.88 μg/mL by increasing electrospinning time to 60 minutes, which exhibited strong antimicrobial activity against S. aureus. In food simulants, the accumulative release amount of silver ions at 25℃ was higher than that at 4℃. The highest release amount, release ratio and release exponent (n) Higuchi’s square-root equation were observed in 3% acetic acid within these simulants, which kinetic constant (k) was 0.00465. However, all of the exponent values in food simulants were less than 0.5, which revealed that the Fickian diffusion could explain the slow release of silver ions in food simulants The electrospun nanofiber with high specific surface increased the release ratio and resulted in the saving of antimicrobial agent dosage under the premise with antimicrobial effect, which created the possibility to reduce the amount of released silver. The results of this study suggest that electrospun coating is a suitable candidate for inclusion in antimicrobial food packaging.
41
Chou, Tzu-Ling, and 周紫綾. "Development of chromogenic sensors for copper and silver ions." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/94053975591690728901.
Повний текст джерелаАнотація:
碩士靜宜大學
應用化學系
103
This work describes the synthesis of two Schiff bases based on an 8-formyl-7-hydroxy-4-methylcoumarin framework, (E)-7-hydroxy-8-((2-hydroxyphenylimino)methyl)-4-methylcoumarin (9) and (E)-7-hydroxy-8-((3-hydroxynaphthalen-2-ylimino)methyl) -4-methylcoumarin (10) and were determined by 1H NMR, 13C NMR and HRMS. The Schiff bases, obtained by condensation of amines and aldehydes, can be applied in the detection of metal ions. Receptors 9 and 10 can detect Cu2+ and indicate its presence by visible color change. In addition, they undergo a photochemical reaction in the presence of Ag+ which also produces a color change. In a mixed solvent system (DMSO/H2O 3 : 7), the color of receptor 9 will change from pale yellow to golden yellow in the presence of Cu2+, while receptor 10 changes from colorless to yellow. By spectroscopic evidence including Job's plots, we have shown receptors 9 and 10 interact with Cu2+ in a 2 : 1 ratio. In a mixed solvent system (CH3OH/H2O 3 : 7) and at low concentration (2 × 10-6 M), receptors 9 and receptor 10 in the presence of Ag+ will undergo a photochemical reaction producing a visible color change from colorless to purple.
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Jian, Zih-Jie, and 簡子傑. "Synthesis of Nano Silver Paste for Ink-jet Printing." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/28858140617141429416.
Повний текст джерелаАнотація:
碩士大同大學
材料工程學系(所)
96
Silver paste has been widely used for thin-film circuit fabrication process, especially for thin-film transistor and flat panel display. The usage of silver paste in traditional semiconductor fabrication process is including screen-printing, coating, and UV-curing. It was denounced with the consuming of time and cost. Ink-jet technology is a noncontact, quiet, and computerized high-speed technique. By using this technology, we can efficiently use the material to make lower cost and more environmentally-friendly. The purpose of this research is to develop an ink-jet printable nano silver paste which can be printed on glass substrate and form a well-adhesion conducting wire. The research points are the synthesis of printable silver paste and the patterning ability of it on glass substrate. The higher concentration and lower particle size is on purpose to synthesis in order to get better electric conductivity. Viscosity and surface tension is adjusted for the piezoelectric printing head to make printable paste. Finally, the nano silver paste is printing on different substrates to examine the properties of adhesion and electric conductivity. The result indicate that tannic acid is not only considered as a reducer but also effect dispersion, viscosity and surface tension of silver ink. Silver particles can be totally reduced from AgNO3 when 15.79g/L tannic acid is added. A well shape and adhesion of silver conducting wire which has 100μm width and 6.7 x 10-6Ω/cm2 sheet resistance can be printed on SnCl2 treated glass.
43
Chen, Shin-Jyi, and 陳信吉. "Preparation of Silver Nano-particles by Thermal Evaporation Method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/26002906797393270752.
Повний текст джерелаАнотація:
碩士南台科技大學
電機工程系
94
This thesis is to study on the preparation of silver nano-particles by thermal evaporation method, and control the size of particles with various inert gas pressure. The advantages include those high yield, high purity. low cost, and simple control of particle size by adjustment of inert gas pressure. It is revealed that inert gas pressure plays important role on the preparation of nano-particles. The morphology, structure, composition, and optical properties of nano-particles are studied by Ultraviolet-Visible spectrophotometer (UV/Vis spectrophotometer), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Eventually, the electrical properties of nano-particles was investigated by using four point probe meter. A serial of sample can be analyzed to understand the special phenomenon. According to the experimental results, the particle size became smaller with increasing inert gas pressure. Nevertheless, the particle size has a critical value at specific pressure, which is the stable condition to grow the smallest particle size. But, the inert gas pressure exceeded specific pressure, the particle size can’t be continue to became smallest one, and the condition of growth is unstable. The absorption spectra of the particles exhibit red shift when the size of particles become smaller. The silver nano-particles are clearly confirmed by X-ray diffraction and TEM analysis. The electrical properties of nano-particles at the range of temperature from 250K to 300K has a fluctuational phenomenon .
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Wei, Wei-Chiang, and 魏維瑲. "Investigation of Silver Nano-fluid Heat Pipe Thermal Performance." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/57791777209481708059.
Повний текст джерелаАнотація:
博士淡江大學
機械與機電工程學系博士班
96
The purpose of this thesis is to study the effects of silver nano-fluids on grooved heat pipe and sintered heat pipe thermal performance. The nano-fluid used in this study is an aqueous solution of 10 nm and 35nm diameter silver nanoparticles. The experiment was performed to measure the temperature distribution and compare the heat pipe thermal resistance using nano-fluid and DI-water. The experimental result of grooved heat pipe showed that thermal resistance decreased 10%~80% compared to DI-water at an input power of 30~60W. And the measured results also show that the thermal resistances of the heat pipe decrease as the silver nanoparticle size and concentration increase. The experimental result of sintered heat pipe, the nano-fluids filled heat pipe temperature distribution demonstrated that the temperature difference decreased 0.56~0.65℃ compared to DI-water at an input power of 30~50W. And the nano-fluid as working medium in heat pipe can up to 70W and is higher than pure water about 20W. In addition, the characteristics of silver nano-fluid concentrations and sizes on copper plate surface wettability were investigated. The experimental results presented that the surface wettability changed with the nano-fluid concentrations and particle sizes. The most significant finding was that the nanoparticle composition percentage, nano-porous layer distribution and particle concentration were influenced mainly by the contact angle. The fundamental mechanisms (effective thermal conductivity, surface wettability and convective heat transfer) of enhanced heat transfer for heat pipes have taken the first step to investigate. The results showed that surface wettability enhancement can be mainly mechanism in improved the heat pipe thermal performance. Due to a significant increase in wettability, thus leading to the capillary force, critical heat flux and condensation enhancement.
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LIN, KE-TING, and 林科町. "Preparation and characterization of nano silver/chitosan composite membranes." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/43398665036885742972.
Повний текст джерелаАнотація:
碩士大葉大學
生物產業科技學系
95
Chitosan salts were prepared by reacting chitosan with hydrochloride, nitric acid, and acetic acid, respectively. Chitosan salt aqueous solutions with concentration 0.5, 0.75, and 1.0 % (w/v) were further prepared and reacted with silver nitrate as well as glutaraldehyde. Solution casting method was used to prepare films. These films showed moisture absorptivity in a range between 16 and 29 %. The FESEM indicated that the size of a majority of the silver compound particles which were dispersed in the films ranged between 6 and 74 nm. Silver compound particles which dispersed in chitosan nitrate salt films had smaller average size than that which dispersed in chitosan hydrochloride salt films. The FTIR spectroscopy revealed that chitosan was crosslinked by glutaraldehyde. In contact angle measurement results, crosslined films had larger contact angle than that whitout crosslinked. Evaluation of tensile strength of films these were conducted using an rheometer. It was found that films with glutaraldehyde had higher tensile strength than that without glutaraldehyde. Elongation was increased with increasing the salt concentration, but decreased with increasing the glutaraldehyde content. From the impedance analysis results, it was found that the conductivity of membranes can be up to 1.2×10-3 S/cm.
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CHEN, YU-NING, and 陳禹寧. "Synthesis, Characterization and Applications of Nano-silver Containing Polystyrene." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/92mq64.
Повний текст джерелаАнотація:
碩士輔仁大學
化學系
106
A nanosilver-containing polystyrene is synthesized by free radical polymerization following by SN2 reaction. Aggregation of silver is restrained from the entanglements of polymer chains that gives rise to uniformed particle size distribution, NMR and FT-IR confirm the chemical structures of polymers. XPS and TEM prove the bonding of S-Ag and particle size distribution of the silver-containing polystyrene. Application of these size-containing polymers to the degradation kinetics study of methylene blue, rate constant (kd) achives 2.29×10-2 min-1, which is 3.4 times faster than that of other similar researches. Additionally, these silver-containing polymers also demonstrate superior sterilization effect on bacterias such as E. coli and Xanthomonas campestris pv.campestris.
47
Liu, Pai-Chung, and 劉百銓. "Manufacturing and Application of Nano-silver wires and rods." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/tt5jx6.
Повний текст джерелаАнотація:
博士淡江大學
機械與機電工程學系博士班
106
In this study, nano silver rods were prepared by silver chloride/silver cluster seed crystal synthesis method and UV exposure and the prepared silver nanorods glycol solution was applied to the conductive ink and photo curable resin coating. The photocurable resin mixed nano silver rod is dip coated on the spider silk, and a spindle lens is formed at the oleophilic end of the spider silk, and the photonic nano jet characteristics of the spindle lens are observed by RGB laser irradiation, in order to overcome the problem of diffraction limit that the optical microscope is hard to avoid. This study proposes a process for fabricating nano-silver crystal seeds and silver nanowires / nanorods that were prepared by seed synthesis method The formed spider silk spindle is used to observe and study the photonic nanojet characteristics in order to overcome the problem of diffraction limit that the optical microscope is hard to avoid. It also proposes a renewal Orange II degradation method by a film of silver chloride and silver nanorods glycol solution. In this process, UV-irradiated silver chloride nanoparticles are added to ethylene glycol solution containing polyvinyl pyrrolidone (PVP) and silver nitrate at 160 C. With the seed crystal synthesis method, this process yielded a solution containing silver nanowires with high aspect ratio (AR) in the ambient, and using a reciprocating piston cylinder to impact the silver nanowires solution at room temperature to obtain a low aspect ratio silver nanorods, In the process of destruction and re-growth, a series of TEM images are recorded to illustrate the growth mechanism of the nano-flag and the nano-silver rod, and demonstrate the theory of percolation. The photonic nanojet characteristics of the spider silk spindle coating with photosensitive resin and nanorods mixed solution at red light (wavelength 617 nm) on a penetration thickness of 3 μm approach the diffraction limit. The silver chloride and nano-bar silver film has complete decolorization effect on the photocatalytic degradation of Orange II azo dye under ultraviolet and visible light irradiation.
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Peng, Yuhsien, and 彭御賢. "A Study on Synthesis of Micro/Nano Silver-Copper Core-Shell Powder with an Electric Conductivity of Silver." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/19308869912870564627.
Повний текст джерелаАнотація:
博士大葉大學
環境工程學系碩士班
100
The purpose of this study is to fabricate the silver-copper core-shell powders with a comparable electric conductivity of silver. Silver-copper core-shell powders are copper powders coated with a thin layer of silver which have sizes less than 10 μm. They have the potential of replacing silver powders and can provide a new price-competitive material for electronic industry. In this study, the silver-copper core-shell powders were synthesized by the silver-copper co-reduction method and the copper electroless plating silver method. In the silver-copper co-reduction method, reducing agents, molar ratios of metal–to-reducing agent, and adding points of the silver sulfate solution were chosen as the primary factors to fabricate silver-copper core-shell powders. The synthetic powders obtained by the silver-copper co-reduction method do not have silver-copper core-shell structure after analyzing by SEM. Also, its electric conductivity is too poor to be measured by the electric conductivity test. Therefore, powders which fabricated by silver-copper co-reduction method can not reach the goal of this research. In the copper electroless plating silver method, silver-copper core-shell powders were fabricated in two stages. Pure copper powders were produced in the first stage and its optimal conditions which concluded by the Taguchi robust design method were: 21.5 kg of copper sulphate and 18.91 kg of phosphate were dissolved into 150 liters pure water at 70 ℃ and 300 RPM. The obtained copper powders have a average size of 7.36 μm. In the second stage, the obtained Cu powders will be subjected to electroless plating method to produce silver-copper core-shell powders. The optimal procedure found in this study were: (1) 2.53 g of Cu powders and 0.08 g of sodium citrate were dissolved into 100 ml pure water for copper powders dispersion, and (2) 1.17 g of silver sulphate and 0.065 g of sodium citrate were dissolved into 250 ml pure water for silver-salt solution, and (3) the silver-salt solution was fast added into copper dispersion under 1000 RPM for 10 min. The obtained optimal powders have a silver-copper core-shell structure which can be proved by using SEM and ESCA. Also, these powders have the same volume resistivity (1.43×10-4 Ω．cm) as pure silver powders when they are analyzed by electric conductivity test. The anti-oxidation property (0.1465 Wt%/min) of these powders is found to be significantly slower than pure copper (0.5745 Wt%/min) by TGA. To conclude, the silver-copper core-shell powders with an electric conductivity of silver and good anti-oxidation properties can be successfully synthesized by the copper electroless plating silver method. The advantage is that their production costs are much cheaper than pure silver powders. Thus, they are suitable to replace silver in electronic conductivity material.
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shieh, Yi jiun, and 謝宜君. "Synthesis and Chacracterization of nano-silver wires/graphene composite materials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/99232621260551263810.
Повний текст джерелаАнотація:
碩士明新科技大學
化學工程與材料科技系碩士班
103
Graphene is the thinnest and hardest nano-materials. Graphene have unique structure and excellent properties which has a wide range of applications in optoelectronics, gas sensors, capacitor, transparent conductive touch panel, composite and hydrogen storage materials. Metal silver has excellent electrical and thermal conductivity. Nano silver wires (NSWs) with high aspect ratio interlace into the network structure then will increase the conductivity. It is anticipated that replace ITO to use as multi-point touch panel material. In conventional, hydrothermal method was used to synthesis NSWs that need more than 2 hr procedure time. It has time-consuming and complex procedure problems. In this thesis, graphene were synthesized on copper foil by thermal chemical vapor deposition. Wrinkled surface of copper due to copper were deposited on a rotating drum and then peel off to form a rolled foil. The optimal copper substrate electropolishing pretreatment parameters were investigated and then a high quality graphene were obtained. The results show that a high quality graphene can be obtained by copper substrate with 60 min electropolishing pretreatment time, and using PEG/H3PO4 ratio of 1：3. NSWs was rapid synthesize by microwave polyol method. The results show that 0.07 M PtCl2, 0.2 M PVP were added into 0.4 M AgNO3 at 160℃ ,with 2 min reaction time , under 500W power. The high quality nano silver wires were obainted. The NSWs were coated on graphene/ITO to prepare a composite. The addition amount of NSW and procedure parameters was studied to improve the conductivity and transmittance of composite. The optimal results show that 1 mg NSWs were dipping into 3 mL Ethanol, with 5000 rpm spin coating on graphene. Resistance and transmittance of NSWs/graphene composite are 30.55 Ω/□, and 95.47% respectively. It is apparent improvement characteristic properties of graphene thin films.
50
Jia-WeiFang and 方家為. "A study of fabricating silver nano-net via surface migration." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/91545527572616789849.
Повний текст джерелаАнотація:
碩士國立成功大學
微電子工程研究所
102
In this thesis, the surface migration of silver nanowires (NWs) was observed and the annealing temperature and dwell time required for NW fusion are investigated. Rapid thermal annealing (RTA) system and high-temperature quartz tube furnace were used this study. When the Ag NWs are treated at elevated temperatures, the Ag atoms at the NWs will migrate and leads to deformation, the overlapped NWs could fused together and forms Ag nano–net. Resistivity and transparency of the Ag nano-net embedded transparent conductive films are studied. This experiment can be divided into two parts. In the first part, two different annealing systems were used to anneal uniformly distributed Ag NWs to form Ag nano-net by linking or fusing the NWs together. Surface migration of Ag NWs after the annealing is also explored. In the second part, I sputtered transparent conductive films with or without Ag nano-net embedded to study thier resistivity and transparency. The results show that Ag atoms will migrate toward low energy surface (111) during the annealing. The adhesion between Ag NWs and the substrate can greatly affect Ag’s surface migration. The surface migration of Ag NWs will distort the shape of the NWs, the overlapped area of the NWs fused together and forms Ag nano-net. This study investigates heating system, temperature and dwell time that suitable to from Ag nano-net as a function of NW density.(RTA,500℃,3min for rarefaction and high-temperature quartz tube furnace,250℃,10min for dense) The resistivity and transmittance results of Ag nano-net embedded AZO films show that NWs fuse together or not does not affects their transmittance, however, the resistivity of the AZO film with fused Ag nano-net embedded has much lower resistivity than those without. Finally, transmittance of 80% with resistance of 9.513 × 10-3Ω-cm AZO film has been fabricated in our lab.