Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22008
C. Mason, S. Vivekanandhan, M. Misra, A. Mohanty
A novel switchgrass (Panicum virgatum) extract mediated green process was demonstrated for the synthesis of silver nanoparticles from silver nitrate solution at ambient temperature. UV-visible spectroscopic analysis indicates the rapid reduction of silver (Ag+) ions by swithgrass extract. The silver nanoparticles began to form at 15 min and the reduction reaction was completed within 2 hours. Synthesized silver nanoparticles were subjected to x-ray diffraction (XRD) for structural characterization, which confirms the FCC symmetry of silver nanoparticles with the lattice parameter of 4.0962 ?. The particle size of bio-synthesized silver nanoparticles was identified through transmission electron microscopic (TEM) analysis and found to be in the range of 20 - 40 nm.
{"title":"Switchgrass (Panicum virgatum) Extract Mediated Green Synthesis of Silver Nanoparticles","authors":"C. Mason, S. Vivekanandhan, M. Misra, A. Mohanty","doi":"10.4236/WJNSE.2012.22008","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22008","url":null,"abstract":"A novel switchgrass (Panicum virgatum) extract mediated green process was demonstrated for the synthesis of silver nanoparticles from silver nitrate solution at ambient temperature. UV-visible spectroscopic analysis indicates the rapid reduction of silver (Ag+) ions by swithgrass extract. The silver nanoparticles began to form at 15 min and the reduction reaction was completed within 2 hours. Synthesized silver nanoparticles were subjected to x-ray diffraction (XRD) for structural characterization, which confirms the FCC symmetry of silver nanoparticles with the lattice parameter of 4.0962 ?. The particle size of bio-synthesized silver nanoparticles was identified through transmission electron microscopic (TEM) analysis and found to be in the range of 20 - 40 nm.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4236/WJNSE.2012.22008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22011
P. Feng, P. Ghosh
In this paper, we propose multi-fin FET design techniques targeted for RF applications. Overlap and underlap design configuration in a base FinFET are compared first and then multi-fin device (consisting of transistor unit up to 50) is studied to develop design limitations and to evaluate their effects on the device performance. We have also investigated the impact of the number of fins (up to 50) in multi-fin structure and resulting RF parameters. Our results show that as the number of fin increases, underlap design compromises RF performance and short channel effects. The results provide technical understanding that is necessary to realize new opportunities for RF and analog mixed-signal design with nanoscale FinFETs.
{"title":"Design Consideration in the Development of Multi-Fin FETs for RF Applications","authors":"P. Feng, P. Ghosh","doi":"10.4236/WJNSE.2012.22011","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22011","url":null,"abstract":"In this paper, we propose multi-fin FET design techniques targeted for RF applications. Overlap and underlap design configuration in a base FinFET are compared first and then multi-fin device (consisting of transistor unit up to 50) is studied to develop design limitations and to evaluate their effects on the device performance. We have also investigated the impact of the number of fins (up to 50) in multi-fin structure and resulting RF parameters. Our results show that as the number of fin increases, underlap design compromises RF performance and short channel effects. The results provide technical understanding that is necessary to realize new opportunities for RF and analog mixed-signal design with nanoscale FinFETs.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22007
Weina Cui, Si-yu Ni, Shunan Shan, Xingping Zhou
The modification of NaYF4:Yb,Er(Tm) nanoparticles synthesized in the presence of an ionic surfactant is critical to their application in biological fields for better solubility and biocompatibility. In this work, NaYF4:Yb,Er(Tm) was transformed from insoluble, inactive to hydrophilic, biocompatible via ligand exchange modification with polyacrylic acid (PAA). Ligand exchange was carried out at room temperature when a colloidal solution of NaYF4:Yb,Er(Tm) in tetrahydrofuran (THF) was treated with excess PAA. The PAA modified NaYF4:Yb,Er(Tm) nanoparticles got better surface properties but with declined inner up-conversion fluorescence. Generally, coating an analogous layer of material outside the core nanoparticles can improve the optical properties of the core. Accordingly, NaYF4:Yb,Er(Tm)/NaYF4 nanoparticles were synthesized before PAA modification to avoid the optical intensity decaying. The result of fluorescence test proved that the water soluble NaYF4:Yb,Er(Tm)/NaYF4/PAA nanocomposites had a sound up-conversion property compared with that of NaYF4:Yb,Er(Tm)/PAA. Furthermore, the up-conversion fluorescence property of the nanocomposite varied with the doping ratio of Er(Tm) to Yb and the possible mechanism for this change was also discussed.
{"title":"A Method to Improve the Up-Conversion Fluorescence of Polymer Modified NaYF4:Yb,Er(Tm) Nanocomposites","authors":"Weina Cui, Si-yu Ni, Shunan Shan, Xingping Zhou","doi":"10.4236/WJNSE.2012.22007","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22007","url":null,"abstract":"The modification of NaYF4:Yb,Er(Tm) nanoparticles synthesized in the presence of an ionic surfactant is critical to their application in biological fields for better solubility and biocompatibility. In this work, NaYF4:Yb,Er(Tm) was transformed from insoluble, inactive to hydrophilic, biocompatible via ligand exchange modification with polyacrylic acid (PAA). Ligand exchange was carried out at room temperature when a colloidal solution of NaYF4:Yb,Er(Tm) in tetrahydrofuran (THF) was treated with excess PAA. The PAA modified NaYF4:Yb,Er(Tm) nanoparticles got better surface properties but with declined inner up-conversion fluorescence. Generally, coating an analogous layer of material outside the core nanoparticles can improve the optical properties of the core. Accordingly, NaYF4:Yb,Er(Tm)/NaYF4 nanoparticles were synthesized before PAA modification to avoid the optical intensity decaying. The result of fluorescence test proved that the water soluble NaYF4:Yb,Er(Tm)/NaYF4/PAA nanocomposites had a sound up-conversion property compared with that of NaYF4:Yb,Er(Tm)/PAA. Furthermore, the up-conversion fluorescence property of the nanocomposite varied with the doping ratio of Er(Tm) to Yb and the possible mechanism for this change was also discussed.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22014
Masahito Ban, Fusako Sasaki
The crystalline fullerene C60 particles were formed and immobilized on poly(dimethylsiloxane) (PDMS) substrates under the various discharge conditions by an ink-jet method, and investigated for the reactive oxygen species (ROS) generation property under visible light irradiation. The particles were synthesized by discharging a toluene solution dissolved C60 and poly(methyl methacrylate) (PMMA) with the ink-jet spotting system. The ROS generation was evaluated by comparisons of the fluorescence intensities measured for the formed particles under green laser irradiation and in a dark room using fluorescent dyes, 2’,7’-dichlorofluorescein diacetate and dihydroethidium. The results of transmission electron microscope (TEM) observation showed that the formed particles consisted of crystalline C60. The optimal ink-jet discharge conditions for synthesizing the particles to generate more ROS were found. In the case of the optimal conditions, the structure in which the needle-like particles were three-dimensionally formed was confirmed. The surface area of the crystalline C60 particles was calculated using the SEM observation results, and it was suggested that when the needle-like finer particles were three-dimensionally formed under the optimal conditions, increasing the surface area lead to an increase in the ROS generation amount.
{"title":"Formation of Photosensitizing Crystalline C 60 Particles by Ink-Jet Method","authors":"Masahito Ban, Fusako Sasaki","doi":"10.4236/WJNSE.2012.22014","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22014","url":null,"abstract":"The crystalline fullerene C60 particles were formed and immobilized on poly(dimethylsiloxane) (PDMS) substrates under the various discharge conditions by an ink-jet method, and investigated for the reactive oxygen species (ROS) generation property under visible light irradiation. The particles were synthesized by discharging a toluene solution dissolved C60 and poly(methyl methacrylate) (PMMA) with the ink-jet spotting system. The ROS generation was evaluated by comparisons of the fluorescence intensities measured for the formed particles under green laser irradiation and in a dark room using fluorescent dyes, 2’,7’-dichlorofluorescein diacetate and dihydroethidium. The results of transmission electron microscope (TEM) observation showed that the formed particles consisted of crystalline C60. The optimal ink-jet discharge conditions for synthesizing the particles to generate more ROS were found. In the case of the optimal conditions, the structure in which the needle-like particles were three-dimensionally formed was confirmed. The surface area of the crystalline C60 particles was calculated using the SEM observation results, and it was suggested that when the needle-like finer particles were three-dimensionally formed under the optimal conditions, increasing the surface area lead to an increase in the ROS generation amount.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22010
M. Sacilotti, D. Chaumont, C. C. Mota, T. C. Vasconcelos, F. Nunes, M. Pompelli, S. Morelhão, A. Gomes
To copy natural photosynthesis process we need to understand and explain the physics underneath its first step mechanism, which is “how to separate electrical charges under attraction”. But this Nature’s nanotechnological creation is not yet available to the scientific community. We present a new interpretation for the artificial and natural photosynthetic mechanism, concerning the electrical charges separation and the spent energy to promote the process. Interface (e–, h+) recombination and emission is applied to explain the photosynthetic mechanisms. This interpretation is based on energy bands relative position, the staggered one, which under illumination promotes (e–, h+) charges separation through the action of an interface electric field and energy consumption at the interface of both A/B generic materials. Energy band bending is responsible by the interface electric field (and the driving force) for the charges separation. This electric field can be as high or above that for p-n semiconductor junctions (104 - 105 V/cm). This physical effect is not considered by most of the researches. Without an electric field and without spending energy to separate electrical charges, any other existing model violates physical laws. The staggered energy band type is the only energetic configuration that permits charges separation under illumination and energy loss to perform the process. Application to natural photosynthesis and artificial photovoltaic material and their energetic configurations are discussed. Examples for A/B being III-V/III-V, TiO2/materials and II-VI/II-VI staggered energy band gap pairs are presented. In the proposed quantum mechanism, plants are able to eliminate most of the 79% of the absorbed visible light, according to the published reflection and transmission data. Moreover, the proposed mechanism can be applied to explain green fluorescent protein - GFP, charge transfer states - CTS and Fluorescent Resonance Energy Transfer - FRET. As recent literature experimental results propose photosynthesis as a quantum controlled mechanism, our proposition goes forward this direction.
{"title":"Interface Recombination & Emission Applied to Explain Photosynthetic Mechanisms for (e-, h+) Charges' Separation","authors":"M. Sacilotti, D. Chaumont, C. C. Mota, T. C. Vasconcelos, F. Nunes, M. Pompelli, S. Morelhão, A. Gomes","doi":"10.4236/WJNSE.2012.22010","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22010","url":null,"abstract":"To copy natural photosynthesis process we need to understand and explain the physics underneath its first step mechanism, which is “how to separate electrical charges under attraction”. But this Nature’s nanotechnological creation is not yet available to the scientific community. We present a new interpretation for the artificial and natural photosynthetic mechanism, concerning the electrical charges separation and the spent energy to promote the process. Interface (e–, h+) recombination and emission is applied to explain the photosynthetic mechanisms. This interpretation is based on energy bands relative position, the staggered one, which under illumination promotes (e–, h+) charges separation through the action of an interface electric field and energy consumption at the interface of both A/B generic materials. Energy band bending is responsible by the interface electric field (and the driving force) for the charges separation. This electric field can be as high or above that for p-n semiconductor junctions (104 - 105 V/cm). This physical effect is not considered by most of the researches. Without an electric field and without spending energy to separate electrical charges, any other existing model violates physical laws. The staggered energy band type is the only energetic configuration that permits charges separation under illumination and energy loss to perform the process. Application to natural photosynthesis and artificial photovoltaic material and their energetic configurations are discussed. Examples for A/B being III-V/III-V, TiO2/materials and II-VI/II-VI staggered energy band gap pairs are presented. In the proposed quantum mechanism, plants are able to eliminate most of the 79% of the absorbed visible light, according to the published reflection and transmission data. Moreover, the proposed mechanism can be applied to explain green fluorescent protein - GFP, charge transfer states - CTS and Fluorescent Resonance Energy Transfer - FRET. As recent literature experimental results propose photosynthesis as a quantum controlled mechanism, our proposition goes forward this direction.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-22DOI: 10.4236/WJNSE.2012.22012
M. Matsuoka, S. Isotani, R. Mansano, W. Sucasaire, R. Pinto, J. Mittani, K. Ogata, N. Kuratani
Thin carbon nitride (CNx) films were synthesized on silicon substrates by reactive RF magnetron sputtering of a graphite target in mixed N2/Ar discharges and the N2 gas fraction in the discharge gas, F N, varied from 0.5 to 1.0. The atomic bonding configuration and chemical composition in the CNx films were examined using X-ray photoelectron spectroscopy (XPS) and the degree of structural disorder was studied using Raman spectroscopy. An increase in the nitrogen content in the film from 19 to 26 at% was observed at FN = 0.8 and found to influence the film properties; normality tests suggested that the data obtained at FN = 0.8 are not experimental errors. The interpretation of XPS spectra might not be always straightforward and hence the detailed and quantitative comparison of the XPS data with the information acquired by Raman spectroscopy enabled us to interpret the decomposed peaks in the N 1s and C 1s XPS spectra. Two N 1s XPS peaks at 398.3 and 399.8 eV (peaks N1 and N2, respectively) were assigned to a sum of pyridine-like nitrogen and -C≡N bond, and to a sum of pyrrole-like nitrogen and threefold nitrogen, respectively. Further, the peaks N1 and N2 were found to correlate with C 1s XPS peaks at 288.2 and 286.3 eV, respectively; the peak at 288.2 eV might include a contribution of sp3 carbon.
{"title":"X-Ray Photoelectron Spectroscopy and Raman Spectroscopy Studies on Thin Carbon Nitride Films Deposited by Reactive RF Magnetron Sputtering","authors":"M. Matsuoka, S. Isotani, R. Mansano, W. Sucasaire, R. Pinto, J. Mittani, K. Ogata, N. Kuratani","doi":"10.4236/WJNSE.2012.22012","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.22012","url":null,"abstract":"Thin carbon nitride (CNx) films were synthesized on silicon substrates by reactive RF magnetron sputtering of a graphite target in mixed N2/Ar discharges and the N2 gas fraction in the discharge gas, F N, varied from 0.5 to 1.0. The atomic bonding configuration and chemical composition in the CNx films were examined using X-ray photoelectron spectroscopy (XPS) and the degree of structural disorder was studied using Raman spectroscopy. An increase in the nitrogen content in the film from 19 to 26 at% was observed at FN = 0.8 and found to influence the film properties; normality tests suggested that the data obtained at FN = 0.8 are not experimental errors. The interpretation of XPS spectra might not be always straightforward and hence the detailed and quantitative comparison of the XPS data with the information acquired by Raman spectroscopy enabled us to interpret the decomposed peaks in the N 1s and C 1s XPS spectra. Two N 1s XPS peaks at 398.3 and 399.8 eV (peaks N1 and N2, respectively) were assigned to a sum of pyridine-like nitrogen and -C≡N bond, and to a sum of pyrrole-like nitrogen and threefold nitrogen, respectively. Further, the peaks N1 and N2 were found to correlate with C 1s XPS peaks at 288.2 and 286.3 eV, respectively; the peak at 288.2 eV might include a contribution of sp3 carbon.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4236/WJNSE.2012.22012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-28DOI: 10.4236/WJNSE.2012.21001
F. Besahraoui, L. Chahed, Y. Bouizem, J. Sib
The enhanced optical absorption measured by Constant Photocurrent Method (CPM) of hydrogenated nanocrystalline silicon thin films is due mainly to bulk and/or surface light scattering effects. A new numerical method is presented to calculate both true optical absorption and scattering coefficient from CPM absorption spectra of nanotextured nano-crystalline silicon films. Bulk and surface light scattering contributions can be unified through the correlation obtained between the scattering coefficient and surface roughness obtained using our method.
{"title":"New Numerical Method to Calculate the True Optical Absorption of Hydrogenated Nanocrystalline Silicon Thin Films","authors":"F. Besahraoui, L. Chahed, Y. Bouizem, J. Sib","doi":"10.4236/WJNSE.2012.21001","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.21001","url":null,"abstract":"The enhanced optical absorption measured by Constant Photocurrent Method (CPM) of hydrogenated nanocrystalline silicon thin films is due mainly to bulk and/or surface light scattering effects. A new numerical method is presented to calculate both true optical absorption and scattering coefficient from CPM absorption spectra of nanotextured nano-crystalline silicon films. Bulk and surface light scattering contributions can be unified through the correlation obtained between the scattering coefficient and surface roughness obtained using our method.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-28DOI: 10.4236/WJNSE.2012.21004
H. K. Chitte, N. Bhat, N. Karmakar, D. Kothari, G. N. Shinde
Silver nanoparticles were synthesized by chemical reduction method. The Ag nanoparticles (AgNP) were characterized using UV-Vis spectroscopy which shows an absorption band at 420 nm confirming the formation of nanoparticles. For any practical application of the silver nanoparticles it is necessary to stabilize it which can be done by making a composite. In the present studies three polymers were chosen such that AgNP could be put to some practical use. Polyvinyl Alcohol (PVA), Polypyrrole (Ppy) and Carboxymethyl cellulose (CMC) are important for use in textiles, electronics and food/drug technologies respectively. Polymeric composites of PVA, PPy, and CMC were prepared by mixing the aqueous solutions of the respective polymers and the colloidal suspension of preformed silver nanoparticles. Various compositions containing 1% to 5% of Ag nanoparticles were prepared. Thin films of these composites were characterized by UV-Vis spectroscopy, X-ray diffraction and Scanning electron microscopy. X-ray diffraction showed the presence of the peaks at 2θ values of 38.1°, 44.2°, 64.4 and 78.2° corresponding to cubic phase of silver metal. SEM photographs revealed the presence of Ag nanoparticles of sizes varying from 40 to 80 nm. The electrical conductivity of these materials was studied using the four probe method. The conductivity was found to increase from 10–6 for control samples to 10–3 S/cm after the formation of the nanocomposites.
{"title":"Synthesis and Characterization of Polymeric Composites Embeded with Silver Nanoparticles","authors":"H. K. Chitte, N. Bhat, N. Karmakar, D. Kothari, G. N. Shinde","doi":"10.4236/WJNSE.2012.21004","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.21004","url":null,"abstract":"Silver nanoparticles were synthesized by chemical reduction method. The Ag nanoparticles (AgNP) were characterized using UV-Vis spectroscopy which shows an absorption band at 420 nm confirming the formation of nanoparticles. For any practical application of the silver nanoparticles it is necessary to stabilize it which can be done by making a composite. In the present studies three polymers were chosen such that AgNP could be put to some practical use. Polyvinyl Alcohol (PVA), Polypyrrole (Ppy) and Carboxymethyl cellulose (CMC) are important for use in textiles, electronics and food/drug technologies respectively. Polymeric composites of PVA, PPy, and CMC were prepared by mixing the aqueous solutions of the respective polymers and the colloidal suspension of preformed silver nanoparticles. Various compositions containing 1% to 5% of Ag nanoparticles were prepared. Thin films of these composites were characterized by UV-Vis spectroscopy, X-ray diffraction and Scanning electron microscopy. X-ray diffraction showed the presence of the peaks at 2θ values of 38.1°, 44.2°, 64.4 and 78.2° corresponding to cubic phase of silver metal. SEM photographs revealed the presence of Ag nanoparticles of sizes varying from 40 to 80 nm. The electrical conductivity of these materials was studied using the four probe method. The conductivity was found to increase from 10–6 for control samples to 10–3 S/cm after the formation of the nanocomposites.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4236/WJNSE.2012.21004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-28DOI: 10.4236/WJNSE.2012.21006
A. Aly, E. Zeidan, A. A. Alshennawy, Aly A. El-Masry, Wahid A. Wasel
Composites formed by adding nano-scale particles to a polymer matrix results in improving electrical, mechanical, and thermal properties of the composite. Good tribological properties can be obtained for polymers filled with nano-scale fillers compared to that filled with micro-scale particles. The friction and wear resistance of these composites is found to increase with increasing filler concentration. It is also possible to use multi-functional fillers to develop high performance composites which cannot be achieved by using a single filler.
{"title":"Friction and Wear of Polymer Composites Filled by Nano-Particles: A Review","authors":"A. Aly, E. Zeidan, A. A. Alshennawy, Aly A. El-Masry, Wahid A. Wasel","doi":"10.4236/WJNSE.2012.21006","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.21006","url":null,"abstract":"Composites formed by adding nano-scale particles to a polymer matrix results in improving electrical, mechanical, and thermal properties of the composite. Good tribological properties can be obtained for polymers filled with nano-scale fillers compared to that filled with micro-scale particles. The friction and wear resistance of these composites is found to increase with increasing filler concentration. It is also possible to use multi-functional fillers to develop high performance composites which cannot be achieved by using a single filler.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4236/WJNSE.2012.21006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-28DOI: 10.4236/WJNSE.2012.21003
R. Singh, K. Gupta, A. Pandey, A. Pandey
Eu+++ and Tb+++ doped Y2O3 nanoparticles have been synthesized by hydrothermal process using yttrium oxo-isopropoxide Y5O(OPri)13 as precursor (OPri = isopropxy). X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoparticle size analyzer and photoluminescence (PL) spectroscopy have been used to characterize these powders. The as synthesized powders gave very sharp peak in the X-ray diffraction suggesting crystalline particles with average particle size between 28 - 51 nm for Eu+++ doped Y2O3 nanoparticles and 43 - 51 nm for Tb+++ doped Y2O3 nanoparticles annealed at 300℃ for 3 h, 4 h and 5 h, which could be unique in comparison to other reports. Transmission electron micrograph investigation of the particles shows single dispersed particles along with agglomerates. The ratio of intensities of transitions in the europium and terbium emission spectrum have been used as structural probe to indicate the local environment around Eu+++ and Tb+++ in the Y2O3 particles.
{"title":"Synthesis and Characterization of Eu +++ Doped Y 2 O 3 (Red Phosphor) and Tb +++ Doped Y 2 O 3 (Green Phosphor) by Hydrothermal Processes","authors":"R. Singh, K. Gupta, A. Pandey, A. Pandey","doi":"10.4236/WJNSE.2012.21003","DOIUrl":"https://doi.org/10.4236/WJNSE.2012.21003","url":null,"abstract":"Eu+++ and Tb+++ doped Y2O3 nanoparticles have been synthesized by hydrothermal process using yttrium oxo-isopropoxide Y5O(OPri)13 as precursor (OPri = isopropxy). X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoparticle size analyzer and photoluminescence (PL) spectroscopy have been used to characterize these powders. The as synthesized powders gave very sharp peak in the X-ray diffraction suggesting crystalline particles with average particle size between 28 - 51 nm for Eu+++ doped Y2O3 nanoparticles and 43 - 51 nm for Tb+++ doped Y2O3 nanoparticles annealed at 300℃ for 3 h, 4 h and 5 h, which could be unique in comparison to other reports. Transmission electron micrograph investigation of the particles shows single dispersed particles along with agglomerates. The ratio of intensities of transitions in the europium and terbium emission spectrum have been used as structural probe to indicate the local environment around Eu+++ and Tb+++ in the Y2O3 particles.","PeriodicalId":66816,"journal":{"name":"纳米科学与工程(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70876052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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