Academic literature on the topic 'Carbonic nanoparticles'
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Journal articles on the topic "Carbonic nanoparticles"
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Demchenko, Alexander. "Excitons in Carbonic Nanostructures." C — Journal of Carbon Research 5, no. 4 (November 12, 2019): 71. http://dx.doi.org/10.3390/c5040071.
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Unexpectedly bright photoluminescence emission can be observed in materials incorporating inorganic carbon when their size is reduced from macro–micro to nano. At present, there is no consensus in its understanding, and many suggested explanations are not consistent with the broad range of experimental data. In this Review, I discuss the possible role of collective excitations (excitons) generated by resonance electronic interactions among the chromophore elements within these nanoparticles. The Förster-type resonance energy transfer (FRET) mechanism of energy migration within nanoparticles operates when the composing fluorophores are the localized electronic systems interacting at a distance. Meanwhile, the resonance interactions among closely located fluorophores may lead to delocalization of the excited states over many molecules resulting in Frenkel excitons. The H-aggregate-type quantum coherence originating from strong coupling among the transition dipoles of adjacent chromophores in a co-facial stacking arrangement and exciton transport to emissive traps are the basis of the presented model. It can explain most of the hitherto known experimental observations and must stimulate the progress towards their versatile applications.
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Lizoňová, Denisa, Monika Majerská, Vlastimil Král, Michal Pechar, Robert Pola, Marek Kovář, and František Štěpánek. "Antibody-pHPMA functionalised fluorescent silica nanoparticles for colorectal carcinoma targeting." RSC Advances 8, no. 39 (2018): 21679–89. http://dx.doi.org/10.1039/c8ra03487g.
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Clark, Andrew J., Devin T. Wiley, Jonathan E. Zuckerman, Paul Webster, Joseph Chao, James Lin, Yun Yen, and Mark E. Davis. "CRLX101 nanoparticles localize in human tumors and not in adjacent, nonneoplastic tissue after intravenous dosing." Proceedings of the National Academy of Sciences 113, no. 14 (March 21, 2016): 3850–54. http://dx.doi.org/10.1073/pnas.1603018113.
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Nanoparticle-based therapeutics are being used to treat patients with solid tumors. Whereas nanoparticles have been shown to preferentially accumulate in solid tumors of animal models, there is little evidence to prove that intact nanoparticles localize to solid tumors of humans when systemically administered. Here, tumor and adjacent, nonneoplastic tissue biopsies are obtained through endoscopic capture from patients with gastric, gastroesophageal, or esophageal cancer who are administered the nanoparticle CRLX101. Both the pre- and postdosing tissue samples adjacent to tumors show no definitive evidence of either the nanoparticle or its drug payload (camptothecin, CPT) contained within the nanoparticle. Similar results are obtained from the predosing tumor samples. However, in nine of nine patients that were evaluated, CPT is detected in the tumor tissue collected 24–48 h after CRLX101 administration. For five of these patients, evidence of the intact deposition of CRLX101 nanoparticles in the tumor tissue is obtained. Indications of CPT pharmacodynamics from tumor biomarkers such as carbonic anhydrase IX and topoisomerase I by immunohistochemistry show clear evidence of biological activity from the delivered CPT in the posttreatment tumors.
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Mikolajczak, Dorian J., and Beate Koksch. "Peptide–Gold Nanoparticle Conjugates as Artificial Carbonic Anhydrase Mimics." Catalysts 9, no. 11 (October 29, 2019): 903. http://dx.doi.org/10.3390/catal9110903.
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We herein describe the design and synthesis of a catalytically active peptide–gold nanoparticle conjugate (Pep-Au-NP) that binds Zn(II) within its peptide monolayer and develops carbonic anhydrase activity. Specifically, a modified variant of the β-sheet forming IHIHIQI-peptide (IHQ), which forms an interstrand 3-His Zn(II)-binding site, was used as a ligand for spherical gold nanoparticles (Au-NPs). The resulting immobilized peptide maintains its ability to form β-sheets, as determined by circular dichroism (CD)-spectroscopy and, thus, maintains its ability to form Zn(II)-binding sites. The addition of Zn(II)-ions to the peptide–gold nanoparticle conjugates (Au@IHQ-NP) resulted in significant improvements in rates of ester hydrolysis of 4-nitrophenyl acetate (4-NPA) and the hydration of CO2 compared to the unconjugated peptide variants. Recycling of the catalyst revealed that Au@IHQ-NP remains intact with at least 94% of its initial activity after five rounds of CO2 hydration. The herein reported results reveal that Pep-Au-NPs are able to perform reactions catalyzed by natural metalloenzymes and open up new possibilities for the implementation of these conjugates.
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Gößl, Dorothée, Helena Singer, Hsin-Yi Chiu, Alexandra Schmidt, Martina Lichtnecker, Hanna Engelke, and Thomas Bein. "Highly active enzymes immobilized in large pore colloidal mesoporous silica nanoparticles." New Journal of Chemistry 43, no. 4 (2019): 1671–80. http://dx.doi.org/10.1039/c8nj04585b.
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Alhumaydhi, Fahad A. "Green Synthesis of Gold Nanoparticles Using Extract of Pistacia chinensis and Their In Vitro and In Vivo Biological Activities." Journal of Nanomaterials 2022 (June 30, 2022): 1–11. http://dx.doi.org/10.1155/2022/5544475.
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The synthesis of metal nanoparticles by using plant extracts is previously explored in phytomedicines. Nanobiotechnology has many applications, including cosmetic, packing, coating, biomedicine, and enhanced biological activity. Keeping in view the importance of Pistacia chinensis, its gold nanoparticles (AuNPs) have been synthesized by the eco-friendless and cost-effective method. In this study, the synthesized nanoparticles were characterized by advanced techniques such as UV-visible spectroscopy, Fourier transform infrared (FT-IR), and atomic force microscope (AFM) analysis. The biological activities of these synthesized nanoparticles were examined in vitro by measuring the enzymatic inhibition potential on urease and carbonic anhydrase and in vivo by determining the analgesic and sedative activities. The UV spectrum indicated various peaks at the range of 530-550 nm, showing nanoparticles formation. The FT-IR spectroscopy of the extracts and AuNPs indicated the presence of NH, C═N, and N═O in the extract involved in the nanoparticles synthesis. The size of nanoparticles was determined by AFM analysis. The AFM showed that the nanoparticles range from 10 to 100 nm and are almost spherical in shape. The synthesized AuNPs exhibited significant urease inhibition potential with an IC50 value of 44.98. Similarly, the nanoparticles exhibited good carbonic anhydrase inhibition with an IC50 value of 53.54 against acetazolamide having IC50 0.13. Pistacia chinensis extract and its AuNPs exhibited excellent attenuation p < 0.01 in acetic acid-induced writhing model at a dose of 15 mg/kg. The synthesized nanoparticles showed a significant sedative effect p < 0.001 compared to the standard drug. This research work has developed a green method to synthesize nanoparticles by using Pistacia chinensis extract and directed the researcher to purify active phytochemicals from Pistacia chinensis involved in nanoparticles synthesized.
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Vinoba, Mari, Margandan Bhagiyalakshmi, Soon Kwan Jeong, Sung Chan Nam, and Yeoil Yoon. "Carbonic Anhydrase Immobilized on Encapsulated Magnetic Nanoparticles for CO2Sequestration." Chemistry - A European Journal 18, no. 38 (August 9, 2012): 12028–34. http://dx.doi.org/10.1002/chem.201201112.
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Cabaleiro-Lago, Celia, and Martin Lundqvist. "The Effect of Nanoparticles on the Structure and Enzymatic Activity of Human Carbonic Anhydrase I and II." Molecules 25, no. 19 (September 25, 2020): 4405. http://dx.doi.org/10.3390/molecules25194405.
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Human carbonic anhydrases (hCAs) belong to a well characterized group of metalloenzymes that catalyze the conversion of carbonic dioxide into bicarbonate. There are currently 15 known human isoforms of carbonic anhydrase with different functions and distribution in the body. This links to the relevance of hCA variants to several diseases such as glaucoma, epilepsy, mountain sickness, ulcers, osteoporosis, obesity and cancer. This review will focus on two of the human isoforms, hCA I and hCA II. Both are cytosolic enzymes with similar topology and 60% sequence homology but different catalytic efficiency and stability. Proteins in general adsorb on surfaces and this is also the case for hCA I and hCA II. The adsorption process can lead to alteration of the original function of the protein. However, if the function is preserved interesting biotechnological applications can be developed. This review will cover the knowledge about the interaction between hCAs and nanomaterials. We will highlight how the interaction may lead to conformational changes that render the enzyme inactive. Moreover, the importance of different factors on the final effect on hCAs, such as protein stability, protein hydrophobic or charged patches and chemistry of the nanoparticle surface will be discussed.
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Bugárová, Nikola, Zdenko Špitálsky, Matej Mičušík, Michal Bodík, Peter Šiffalovič, Martina Koneracká, Vlasta Závišová, et al. "A Multifunctional Graphene Oxide Platform for Targeting Cancer." Cancers 11, no. 6 (May 29, 2019): 753. http://dx.doi.org/10.3390/cancers11060753.
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Diagnosis of oncological diseases remains at the forefront of current medical research. Carbonic Anhydrase IX (CA IX) is a cell surface hypoxia-inducible enzyme functionally involved in adaptation to acidosis that is expressed in aggressive tumors; hence, it can be used as a tumor biomarker. Herein, we propose a nanoscale graphene oxide (GO) platform functionalized with magnetic nanoparticles and a monoclonal antibody specific to the CA IX marker. The GO platforms were prepared by a modified Hummers and Offeman method from exfoliated graphite after several centrifugation and ultrasonication cycles. The magnetic nanoparticles were prepared by a chemical precipitation method and subsequently modified. Basic characterization of GO, such as the degree of oxidation, nanoparticle size and exfoliation, were determined by physical and chemical analysis, including X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and atomic force microscopy (AFM). In addition, the size and properties of the poly-L-lysine-modified magnetic nanoparticles were characterized. The antibody specific to CA IX was linked via an amidic bond to the poly-L-lysine modified magnetic nanoparticles, which were conjugated to GO platform again via an amidic bond. The prepared GO-based platform with magnetic nanoparticles combined with a biosensing antibody element was used for a hypoxic cancer cell targeting study based on immunofluorescence.
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Duart, Marcelo Adriano, Oscar Endrigo Dorneles Rodrigues, and Sérgio Roberto Mortari. "Carbonic nanoparticles and C-S-H insertion into cementitious nanocomposite." International Journal of Advanced Engineering Research and Science 5, no. 5 (2018): 14–19. http://dx.doi.org/10.22161/ijaers.5.5.2.
Full textDissertations / Theses on the topic "Carbonic nanoparticles"
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Khelifa, Hocine. "Propriétés diélectriques des nanofluides : tenue diélectrique, électrisation statique, décharges partielles et décharges surfaciques." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0048.
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Cette thèse explore le développement, la préparation et la caractérisation des nanofluides (NFs) pour améliorer la performance diélectrique des liquides d'isolation couramment utilisés dans les transformateurs de puissance, y compris les esters synthétiques, les esters naturels et les huiles minérales en incorporant différents types de nanoparticules (NPs). Ces dernières sont conductrices (Fe3O4, C60, et Gr), semiconductrices (ZnO et CuO) et isolantes (Al2O3, ZrO2, SiO2 et MgO). L'étude vise à améliorer les propriétés diélectriques, notamment la tension de claquage en courant alternatif, la résistance aux décharges partielles, la tendance à la charge électrostatique et les caractéristiques de décharge de surface. Une analyse complète couvrant l'évolution historique, les techniques de préparation (méthodes en une ou deux étapes) et les mécanismes de stabilisation essentiels pour obtenir des nanofluides stables avec des propriétés diélectriques optimales est présentée. Les protocoles de préparation des NP, ainsi que les différents montages expérimentaux et les méthodes utilisées pour les caractériser sur le plan diélectrique, sont ensuite décrits. L'impact des caractéristiques des NPs, telles que le type, la taille, la concentration et le traitement de surface, sur les performances diélectriques des liquides de base est systématiquement évalué. Les données expérimentales sont ensuite analysées à l'aide d'outils statistiques tels que le test d'adéquation d'Anderson-Darling et l'analyse de probabilité de Weibull, et les tensions correspondant à des niveaux de risque de 1 %, 10 % et 50 % ont été déterminées. Les mécanismes impliqués dans l'amélioration/la détérioration de la tension de claquage en courant alternatif sont discutés. Les résultats expérimentaux indiquent que les nanofluides (NFs) améliorent de manière significative les propriétés diélectriques en réduisant l'activité de décharge partielle, la tendance à la charge électrostatique et la longueur d'arrêt des décharges de surface. Cette amélioration est obtenue en influençant la mobilité des charges dans les liquides. Les nanoparticules (NPs) conductrices et isolantes, en particulier Fe3O4 et Al2O3, présentent des avantages substantiels qui peuvent contribuer à atténuer les événements de rupture et à prolonger la longévité des équipements. En outre, l'interaction des nanoparticules aux interfaces solide-liquide affecte les comportements de décharge de surface, ce qui renforce le rôle des nanofluides dans l'amélioration de la durabilité de l'isolationThis thesis explores developing, preparing, and characterizing nanofluids (NFs) to enhance the dielectric performance of insulation liquids commonly used in power transformers, including synthetic esters, natural esters, and mineral oils by incorporating different types of nanoparticles (NPs). These later being conducting (Fe3O4, C60, Gr), semi-conducting (ZnO and CuO), and insulating (Al2O3, ZrO2, SiO2, and MgO). The study aims to improve dielectric properties, including the AC breakdown voltage, partial discharge (PD) resistance, electrostatic charging tendency, and surface discharge characteristics. A comprehensive analysis covering the historical evolution, preparation techniques (one-step and two-step methods), and stabilization mechanisms essential for achieving stable nanofluids with optimal dielectric properties is presented. The preparation protocols of NFs, as well as the various experimental set-ups and methods used to characterize them dielectrically, are then described. The impact of NP characteristics, such as the type, size, concentration, and surface treatment, on the dielectric performance of base liquids is systematically assessed. The experimental data are then analyzed using statistical tools such as the Anderson-Darling goodness-of-fit test and Weibull probability analysis, and the voltages corresponding to 1%, 10%, and 50% risk levels were determined. The involved mechanisms in the improvement/deterioration of AC breakdown voltage are discussed. The experimental results indicate that nanofluids (NFs) significantly enhance the dielectric properties by reducing partial discharge activity, the electrostatic charging tendency, and the stopping length of surface discharges. This improvement is achieved by influencing charge mobility within the liquids. Both conducting and insulating nanoparticles (NPs), particularly Fe3O4 and Al2O3, demonstrate substantial benefits, which can help mitigate breakdown events and extend equipment longevity. Additionally, the interaction of nanoparticles at solid-liquid interfaces affects surface discharge behaviors, further supporting the role of nanofluids in enhancing insulation durability
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Cornelio, Benedetta. "Nanoparticules de palladium comme catalyseurs : Conception, analyses et application pour la préparation de dérivés bisaryliques d'intérêt biologique." Thesis, Reims, 2014. http://www.theses.fr/2014REIMP203.
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Un grand nombre de 3,4-bisindolylmaléimides possède une activité inhibitrice des protéine-kinases. Les 3-isothiazolone-1,(1)-(di)oxydes pouvant être considérées comme des analogues de la maléimide, la fonctionalisation des 5-chloro- et 4,5-dichloro-3-isothiazolone 1,(1)-(di)oxydes par des réactions de couplage palladocatalysé de Suzuki-Miyaura, permet d'accéder aux analogues “thia” des 3,4-bisindolylmaléimides. La synthèse de sulfonamides primaires tels que les dérivés 4-(hétéro)aryl substitués du benzènesulfonamide comme inhibiteurs potentiels de l'anhydrase carbonique, a également été envisagée dans ce travail.Une collection de matériaux hybrides constitués de nanoparticules de palladium adsorbées sur des nanostructures de carbone a été préparée et testée dans des réactions de couplages palladocatalysés, comme catalyseurs en milieu hétérogène. Le plus efficace d'entre eux, associant des nanoparticules de palladium stabilisées par le dodécanethiol et adsorbées sur des nanotubes de carbones “multi-walled”, a été employé afin de préparer vingt-quatre nouveaux dérivés 4-(hétéro)aryl substitués du benzènesulfonamide. L'échec de l'utilisation de ce catalyseur dans les reactions de fonctionalisation des isothiazolone-1,(1)-(di)oxydes nous a contraints à employer un catalyseur plus conventionnel, le PdCl2(dppf)•CH2Cl2.Le dernier volet de ce projet visait à concevoir des catalyseurs à base de nanoparticules de palladium encapsulées dans des nanofibres de carbone “grafitisées” (nanoréacteurs). Une série de nanoréacteurs a pu être préparée et nous avons étudié l'effet du confinement généré à l'intérieur de la nanofibre, sur la réaction palladocatalysée de Suzuki-Miyaura3,4-bisindolylmaleimides possess an inhibitory activity against protein kinase. Because 3-isothiazolone-1,(1)-(di)oxide can be considered as maleimide analog, 5-chloro and 4,5-dichloro-3-isothiazolone-1,(1)-(di)oxide were functionalised using a palladium-catalysed Suzuki-Miyaura cross-coupling reaction achieving the “thia” analogs of 3,4-bisindolylmaleimides. We were also interested in the preparation primary sulfonamides such as 4-(hetero)aryl substituted benzenesulfonamides as carbonic anhydrases inhibitors.A series of hybrid materials comprising palladium nanoparticles adsorbed on carbon nanostructures has been prepared and tested as heterogeneous catalysts of palladium-mediated cross-coupling reactions. The best catalyst, resulting in palladium nanoparticles stabilised by dodecanethiol adsorbed on multi-walled carbon nanotubes, was employed in Suzuki-Miyaura reactions for the preparation of twenty-four new 4-(hetero)aryl substituted benzenesulfonamides. As this catalyst failed in the functionalisation of isothiazolone-1,(1)-(di)oxides, this latter was realised using a more conventional catalyst, PdCl2(dppf)•CH2Cl2.A last part of the project aimed to the conception of catalysts made of palladium nanoparticles encapsulated in graphitised carbon nanofibres (nanoreactors). We prepared a series of nanoreactors and we studied the effect of the confinement inside the nanofibre channel on the Suzuki-Miyaura cross-coupling reaction
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Ben, Sghaier Asma. "Hybrides polymer materials organic/inorganic nanoparticule." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1163.
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La chimie d'interface du diazonium a progressé au cours des dernières années et s'est pratiquement impliquée dans tous les domaines de la science et technologie des matériaux. L’utilisation des sels de diazonium est justifiée par le fait qu’ils adhèrent aux surfaces avec de fortes énergies de liaison, en particulier sur le carbone sp², ce qui en fait d’excellents agents de couplage pour les polymères aux surfaces. Dans ce contexte, nous avons travaillé sur deux types de nanohybrides de nanotubes de carbone (NTC) : NTC-polytriazole (NTC-PTAz) et NTC-colorant. Le nanohybride NTC-PTAz a été synthétisé par polymérisation « click » en surface. Pour ce faire, les NTCs ont été greffés de groupes 4-azidophényle à partir du sel de diazonium correspondant. Le NTC modifié (NTC-N3) a servi de support pour une polymérisation confinée en surface de type polyaddition générant ainsi le nanohybride NTC-PTAz. Ce matériau a été caractérisé par ATG, XPS, IR et Raman. Ses applications potentielles sont dans le développent d’adsorbants de métaux lourds, l’immobilisation de nanocatalyseurs ou pour le stockage des gaz. La seconde partie de la thèse est plus étoffée et porte sur les nanotubes de carbone greffés de colorants diazotés Rouge Neutre (NR), Azure A (AA) et Rouge Congo (CR). L’analyse fine de ces matériaux a révélé une très forte adhésion des colorants aux NTCs et les couches superficielles ont des épaisseurs de 2 à 6 nm, sont homogènes et continues. Les NTC-colorant ont été incorporés dans des matrices élastomères de type EVA pour la réalisation d’actionneurs opto-thermiques implantés dans des pads pour non-voyant. Dans les matrices EVA, les NTCs greffés de colorants servent à capter la lumière et induire un changement de forme dans le pad qui soit palpable par le non voyant (250 µm). Les matrices EVA renforcées de nos nanotubes greffés de colorants ont été réalisées et testées par analyse mécanique dynamique. Les composites NTC/colorant-EVA sont flexibles et prometteurs pour le développement de nouveaux types des pads tactiles pour les non-voyants. Les nanohybrides NTC-NR ont servi comme capteurs chémo-résistifs pour la reconnaissance moléculaire de l’acétone.Dans une dernière application, le nanohybride CNT-CR a été étudié en tant qu’électrocatalyseur pour l’oxydation directe du méthanol. Des résultats intéressants ont été obtenus avec ces nanohybrides mais des améliorations significatives (rapport 3) des propriétés électrocatalytiques ont été obtenues avec des CNT-CR décorés avec des nanoparticules d'or. Le système électrocatalytique nouvellement conçu pourrait être considéré pour différentes applications prometteuses, notamment les capteurs, les biocapteurs, les catalyseurs hétérogènes pour les piles à combustible. Pour résumer, les nanohybrides à base de CNT nouvellement conçus présentent des performances uniques attribuées à la polyvalence de la chimie d'interface du diazonium pour la fixation efficace de couches moléculaires et macromoléculaires fonctionnelles. Les nanohybrides novateurs servent de blocs de construction pour la conception de matériaux nanocomposites à hautes performances potentiellement utiles dans les nouveaux défis socio-économiques tels que l’environnement, la biomédecine et l’énergieDiazonium interface chemistry has progressed over the last few years and practically involved in all areas of materials science and engineering. The rationale for employing diazonium salts is that they attach to surfaces with remarkable bond energies, particularly on sp² carbon materials, making them an ideal coupling agent for polymers to surfaces In this context, novel CNT-polytriazole (CNT-PTAz) and CNT-dye nanohybrids were designed and thoroughly characterized. First, CNT-PTAz nanohybrid was prepared by click polymerization: multiwalled carbon nanotubes (CNTs) were modified with azidophenyl groups (CNT-N3) from 4-azidobenzenediazonium precursor and served as nanoscale platform for the surface confined polyaddition. The CNT-PTAz nanohybrid was characterized by TGA, XPS, IR, and Raman. The robust CNT-PTAz is robust and has potential in developing heavy metal adsorbents, nanosupport for catalysts or for gas storage. In the second major part, we grafted CNT with diazotized Neutral red (NR), Azure A (AA) and Congo Red (CR) dyes by simple, spontaneous reaction of the diazonium salts and CNTs in water, at RT. A thorough investigation of the nanohybrids showed that the adhesion is strong (CNT-dye C-C bond energy higher than 150 kJ/mol), and the layer is uniform. These nanohybrids further served to reinforce ethylene-vinyl acetate (EVA) an elastomeric matrix. The reinforced matrix is flexible and serves as optothermal actuators where the grafted dye catches the light to induce mechanical changes in the matrix monitored by dynamic mechanical analysis. CNT/dye-reinforced EVA is a promising flexible composite for developing new types of visual-aid tablet for visually impaired people. The versatile CNT-dye nanohybrids are also unique chemiresistive gas sensors for the molecular recognition of acetone vapours. In a final application, CNT-CR nanohybrid was investigated as an electrocatalyst for the Direct Oxidation of Methanol. Interesting results were obtained with these nanohybrids but significant improvements (3-fold) of the electrocatalytic properties were achieved with CNT-CR decorated with gold nanoparticles. The newly designed electrocatalytic system could be regarded for different promising applications most likely as for sensors, biosensors, heterogeneous catalysts for fuel cells and for nanotechnology To summarize, newly designed CNT-based nanohybrids have unique performances ascribed to the versatility of the diazonium interface chemistry in efficiently attaching functional molecular and macromolecular layers. The novel nanohybrids serve as building blocks for designing high performance nanocomposite materials relevant to challenging timely social economic issues, namely environment, biomedicine and energy
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Mucha, Sebastian. "Synthesis, characterisation, modelling, and applications of carbon quantum dots of various shapes." Electronic Thesis or Diss., Université de Montpellier (2022-....), 2023. http://www.theses.fr/2023UMONS045.
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La découverte de l'émission de lumière à température ambiante provenant d'impuretés carbonées en 2004 a déclenché des recherches intensives sur les boite quantiques de carbone (CD). Les CD sont considérés comme des alternatives aux nanostructures luminescentes contenant des métaux lourds. Elles peuvent être produites à faible coût, présentent une faible cytotoxicité, une fluorescence excitée à un photon (OPEF) efficace et réglable, une et photorésistance élevée. Néanmoins, leur fluorescence excitée à deux photons (TPEF) et l'absorption à deux photons (TPA), ainsi que les stratégies de modifications chimiques permettant de varier OPEF et TPEF nécessitent une meilleur compréhension.Dans ce travail de these trois nouveaux types de CD sont synthétisées et caractérisées.Une attention particulière est portée à: 1) l'élaboration de nouvelles procédures de synthèse et de purification des CD, 2) la caractérisation structurale des précurseurs moléculaires etdes CD, 3) les études sur les propriétés d'absorption et de fluorescence dans les régimes àun et deux photons, 4) l'évaluation du potentiel d'application des CD dans les essais biochimiques, 5) la compréhension de leurs relations structure-propriété. Le mémoire se compose de quatre sections principales. La première décrit les boites polymériques (PD) dérivés de l’acétone (fractions hydrophiles et hydrophobes), produites (en grande quantité, de l’ordre de gramme) par une nouvelle méthode (une réaction aldolique médiée parune base). Ces PD possèdent une morphologie quasi-sphérique (chaines de polymères enchevêtrées), mais de compositions (le rapport de groupes hydroxyle et carbonyle et des chaînes aliphatiques) différentes. Leur OPEF est de bleu verdâtre et dépend de la longueur d’onde de l'excitation. Nous considérons que l'émission provient de l'ensemble des sous-fluorophores avec un effet de réticulation amélioré. La deuxième section traite spécifiquement les PD hydrophiles, de TPEF vert intense et une forte performance TPA dans la première fenêtre biologique. Ils ne présentent ni photoblanchiment, ni cytotoxicité, ne modifient pas la structure des protéines secondaires, et leurs signaux OPEF et TPEF des PD semblent être améliorés dans l’environnement protéique. Elles peuvent donc être utilisés comme agents sélectifs et efficaces dans le sondage réversible et non destructif des albumines dans des conditions physiologiques simulées. La troisième section décrit de boites de carbone à base d'acide folique (FA CND), synthétisées par traitement hydrothermal de molécules FA. Dopées à l'azote, de structures internes hétérogènes (constituées de domaines de carbone hybridisés sp2 ou sp3), riches en groupes polaires (par exemple carboxyles et hydroxyles), elles présentent en milieu aqueux des OPEF et TPEF de couleur bleu intense; leur spectre TPA couvre la région rouge/NIR. Ces FA CND ont été appliqués à la bioimagerie des figures de la myéline. La quatrième section concerne les CND dérivés du phloroglucinol (PG). Nous avons élaboré des protocoles de synthèse (basés sur des méthodes de décomposition solvothermique et thermique) de trois fractions de PG CND, émettant en bleu, vert et jaune. Les CND PG ont une structure hétérogène (avec des domaines de carbone sp2 et sp3), riche en groupes oxygénés. Leur signaux OPEF et TPEF, monochromatiques et intenses (accordables dans la gamme de couleurs bleu-orange) sont sensibles aux liaisons hydrogène entre les CND et les molécules de solvant. Les CND PG sont aussi des absorbeurs efficaces à deux photons dans la large gamme de longueurs d'onde. Nous avons identifié deux stratégies chimiques pour ajuster la couleur de l'émission de PG CND: i) variantions de la présence des groupes oxygénés avec les domaines π conjugués et ii) modification du réseau de liaisons hydrogène.Nous sommes convaincus que cette recherche doctorale constitue une pièce essentielledu puzzle dans le développement ultérieur des CD en tant qu'émetteurs OPEF et TPEFThe discovery of room-temperature light emission from carbogenic impurities in 2004 triggered intensive research on carbon dots (CDs). CDs are considered innocuous alternatives for heavy metal-containing luminescent nanostructures. They possess low cytotoxicity, efficient (and tuneable) one-photon excited fluorescence (OPEF), high photoresistance, and low-cost production. Nevertheless, their two-photon excited fluorescence (TPEF) and the corresponding two-photon absorption (TPA) must be better characterized. In addition, the chemical tuning strategies for both OPEF and TPEF were not fully understood yet. These aspects limit the application potential of CDs.To pursue the PhD project, three types of novel CDs are considered. We investigate those CDs with particular attention paid to 1) elaboration of new synthesis and purification procedures, 2) structural characterization of molecular precursors and CDs, 3) studies on absorption and fluorescence properties in one- and two-photon regimes, 4) examination of their application potential in biochemical assays, and 5) understanding of their structure-property relations.The PhD work is divided into four main parts.The first section describes acetone-derived polymer dots (PDs) (hydrophilic and hydrophobic fractions). They were produced by a new gram-scale method via base-mediated aldol reaction. All PDs reveal quasi-spherical morphology and polymeric design. However, they differ in the contribution of hydroxyl and carbonyl groups, and aliphatic chains. PDs exhibit greenish-blue OPEF with an excitation-dependent trend. We consider that emission arises from the ensemble of sub-fluorophores with the crosslink-enhanced effect.In the second part, we focus on hydrophilic PDs. They demonstrate an intense green TPEF and a strong TPA performance in the first biological window. They show no cytotoxic effects nor photobleaching. Interactions between serum albumins and PDs are then explored. Both OPEF and TPEF signals of PDs appear to be enhanced in the proteinous environment. Meanwhile, PDs do not change the secondary protein structure. Finally, we confirm that PDs can be used as selective and efficient agents in reversible and non-destructive probing of albumins in simulated physiological conditions.The third section reports on folic acid-based carbon nanodots (FA CNDs). These nanostructures were synthesized through the hydrothermal treatment of FA molecules. Nitrogen-doped FA CNDs possess heterogeneous internal structures, consisting of sp2-/sp3-hybridized carbon domains. They are rich in polar groups (e.g. carboxyls and hydroxyls). FA CNDs exhibit efficient blue OPEF and TPEF in aqueous media; their TPA spectrum covers the red/NIR region. Finally, FA CNDs are applied in the bioimaging of myelin figures in cooperation with other scientists.The fourth section is addressed to phloroglucinol-derived (PG) CNDs. We elaborated protocols to produce three fractions of PG CNDs using solvothermal and thermal decomposition methods. PG CNDs have a heterogeneous design (with sp2- and sp3-carbon domains) which is rich in oxygenous groups. PG CNDs provide monochromatic and intense OPEF and TPEF signals (tuneable in the blue-orange colour range) - responsive to hydrogen bonds between CNDs and solvent molecules. PG CNDs appear to be also effective two-photon absorbers in the wide wavelength range. Finally, we recognize two chemical strategies to tune the emission of PG CNDs: i) the contribution of oxygenous groups with the conjugated π-domains andii) the hydrogen-bond network.We are convinced that this PhD research is an essential piece of the puzzle in the further development of CDs as OPEF and TPEF emitters
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Dichiara, Anthony. "Etude chronologique de la formation de nanotube de carbone par CVD d'aérosol à l'aide de diagnostics in situ : des premiers instants à la fin de la croissance." Phd thesis, Ecole Centrale Paris, 2012. http://tel.archives-ouvertes.fr/tel-00763604.
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Dans le vaste domaine des nanosciences et nanotechnologies, les nanotubes de carbone (NTC) suscitent un intérêt particulier en raison de leur structure originale qui leur confère des propriétés exceptionnelles. Alors que le nombre d'applications ainsi que la quantité de NTC produite ne cessent d'augmenter chaque année, il est essentiel de comprendre les mécanismes régissant la formation de ces nanomatériaux afin de contrôler leur structure et leur organisation, optimiser les rendements, diminuer les risques sanitaires et environnementaux et améliorer les performances des matériaux et composants sous-jacents. Parmi les techniques de synthèse répertoriées, la CVD d'aérosol (Chemical Vapor Deposition) développée au laboratoire MSSMat, permet la croissance continue de NTC multi-feuillets de haute qualité sur divers substrats par l'injection simultanée de sources carbonées liquide (xylène) et gazeuse (acétylène) et de précurseur catalytique (ferrocène) dans un réacteur porté à une température comprise entre 400 et 1000°C. L'objectif de cette étude a consisté à examiner les différentes étapes de la formation des NTC dès l'injection des précurseurs jusqu'à la fin de la croissance. Grâce une nouvelle approche expérimentale faisant intervenir plusieurs diagnostics in situ couplés à des modèles numériques, nous avons pu suivre l'évolution des différents réactifs et produits lors de synthèses dans des conditions thermodynamiques (flux de gaz et températures) et chimiques (concentrations des différents précurseurs) variées. De fait, après avoir examiné l'évolution spatiale des gouttelettes formées lors de l'injection, la germination des nanoparticules en phase gazeuse a été étudiée par incandescence induite par laser (L2I) et spectroscopie de plasma induit par laser (LIPS). Une relation entre la taille de ces particules et celle des NTC a ainsi pu être mise en évidence. Les réactions chimiques pendant la synthèse ont ensuite été analysées par spectrométrie de masse et chromatographie en phase gazeuse. Différents mécanismes réactionnels ont ainsi pu être identifiés en fonction des sources de carbone utilisées, alors que l'effet de l'hydrogène sur la croissance, soit accélérateur ou soit inhibiteur selon les conditions, a été étudié. Les rôles du substrat ont par ailleurs été examinés en comparant la croissance et la morphologie des NTC obtenus sur différentes surfaces telles que des plaques de quartz, des fibres de carbone ou des micro-particules d'alumine, de carbure de silicium, de carbure de titane et de graphène de formes variées. L'effet catalytique de certains substrats ou mélanges de substrats sur la croissance des NTC a d'ailleurs été mis en évidence, de même que l'importance du rapport surface/volume des substrats sur les rendements massiques des NTC. La cinétique de croissance des NTC a finalement été étudiée et différents mécanismes à l'origine de la désactivation des catalyseurs ont été identifiés. Enfin, les différentes nanostructures hybrides issues de la croissance de NTC sur différents substrats ont servi à concevoir des matériaux composites multi-fonctionnels à hautes-performances dont les propriétés électriques, thermiques et mécaniques ont été analysées.
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Gautier, Maxime. "Etude de la formation de nanoparticules de carbone au cours de la décomposition thermique d'hydrocarbures : application à la coproduction de noir de carbone et d'hydrogène par craquage thermique du méthane par voie plasma." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM061/document.
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Cette thèse s’inscrit dans le cadre du développement d’un procédé de décarbonation directe du méthane par voie plasma pour la coproduction de noir de carbone et d’hydrogène. Ce procédé est particulièrement intéressant dans la contexte d'un mix électrique faiblement carboné en offrant une solution pour diminuer drastiquement les émissions des procédés actuels de production de noir de carbone et d’hydrogène qui comptent parmi les procédés actuels les plus polluants en termes d'émissions de CO2. A court terme, la viabilité économique de ce procédé passe par la valorisation simultanée de ces deux produits : noir de carbone et hydrogène. À plus long terme, il pourrait représenter une réelle alternative à la capture et le stockage du CO2.Cette étude a pour but de proposer des méthodes numériques fiables et robustes afin de mieux comprendre, contrôler, voire optimiser les caractéristiques morphologiques des noirs de carbone issus de ce procédé, caractéristiques qui jouent un rôle primordial sur la qualité et les applications des noirs de carbone. Elle traite ainsi de l’évolution de systèmes carbonés en partant du combustible sous sa forme moléculaire jusqu’à la formation de nanoparticules puis de microstructures solides et aborde les phénomènes de nucléation, de croissance chimique, de croissance par coagulation, de maturation et d’agrégation.Des outils et des méthodes numériques ont ainsi pu être développés afin de simuler la formation de particules solides au sein d’un écoulement fluide. Ceux-ci purent être implémentés avec succès à un code CFD. Enfin des simulations numériques du procédé en question ont été réalisées en intégrant les phénomènes de transferts thermiques et de turbulence spécifiques aux plasmas thermiquesThis thesis takes part of the development of a direct decarbonation process of methane by plasma to produce both carbon black and hydrogen. This process is particularly interesting in an electrical mix context with low carbon emission. It proffers a solution to reduce drastically CO2 emissions rejected by the current carbon black and hydrogen ways of production, which are ones of the most polluting industrial processes.This study aims to develop reliable and robust numerical methods for a better understanding and a greater control of the morphologic features of the carbon black generated. These features play a key role in the quality and applications of the carbon black produced. This research retraces the evolution of the carbon structure from the molecules of the fuel to the formation of nanoparticles and solid microstructures. It tackles different phenomenon such as: nucleation, chemical growth, coagulation, maturity and aggregation.Numerical tools and methods were developed thereby and enable to simulate carbon particle formation. They were successfully implemented in a commercial CFD software. Eventually numerical simulation of the plasma process were performed, integrating heat transfers and turbulence
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Larue, Camille. "Impact de nanoparticules de TiO2 et de nanotubes de carbone sur les végétaux." Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00765312.
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Dans le contexte du développement exponentiel des nanotechnologies, les nanomatériaux sont susceptibles de se disséminer dans l'environnement. Les végétaux sont un élément sensible des écosystèmes car ils constituent une interface entre l'eau, le sol et l'air et se situent à la base de la chaine trophique. Cette étude avait pour but d'évaluer l'impact des nanoparticules de TiO2 et des nanotubes de carbone sur les végétaux, et plus particulièrement sur le blé et le colza. L'accent a également était mis sur la caractérisation des nanomatériaux employés. Nous avons mis en évidence l'accumulation racinaire et le transfert vers les feuilles des nanoparticules de TiO2 et des NTC dans le blé et le colza après une exposition en hydroponie. Les nanoparticules de TiO2 sont également accumulées dans les plantes lors d'une exposition racinaire sur sol ou encore lors d'une exposition par voie aérienne. Les nanoparticules de TiO2 s'accumulent dans les végétaux à hauteur de quelques dizaines voire centaines de mg Ti/kg MS, leur phase cristalline n'est pas modifiée et ces nanoparticules ne se dissolvent pas lors de leur transfert dans le végétal. Les NTC s'accumulent en plus faible quantité (centaines de µg NTC/kg MS) et il semble qu'ils soient altérés par le contact avec le végétal. Ces nanomatériaux affectent peu le développement des végétaux. Sur huit tests réalisés, seule l'élongation racinaire s'est révélée être un critère sensible, avec une induction de l'élongation pour les NPs et les NTC présentant le plus faible diamètre nominal. Enfin, une nette influence du diamètre nominal des nanomatériaux a pu être mise en évidence, contrôlant ainsi leur internalisation, leur transfert et leurs effets biologiques sur les végétaux.
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Bonnin, Maëlle. "Diversité structurale des agrégats de carbone et d'hydrogène, implications pour les porteurs des bandes aromatiques infrarouges." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS156/document.
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L’émission IR de nombreuses lignes de visée dans le milieu interstellaire (ISM) présente des bandes d’émission appelées AIBs, habituellement attribuées aux hydrocarbures aromatiques polycyliques (PAHs). Identifier les porteurs des AIBs permettrait une meilleure compréhension de l’évolution de la matière carbonée dans l’ISM. Le but est ici de pouvoir comparer les AIBs avec des spectres IR théoriques et expérimentaux de nanoparticules hydrocarbonées. Le travail réalisé ici a porté sur l’analyse structurale de ces systèmes. Des systèmes moléculaires désordonnés contenant de 24 à 60 atomes de carbone sont générés par des simulations Monte Carlo par échange de répliques à l’aide du potentiel réactif empirique AIREBO. Après minimisation de leur énergie potentielle, les structures ainsi créées sont caractérisées à l’aide de divers paramètres d’ordre. L’évolution de l’organisation structurale est analysée en fonction de la taille et de la composition chimique (rapport C/H) des systèmes. Les structures obtenues présentent une grande diversité. L’étude statistique des différents paramètres d’ordre permet de mettre en évidence des tendances. La forme globale prise par les agrégats dépend de leur taille. Les atomes d'hydrogène, souvent périphériques sur les structures de type cage, favorisent un degré d'organisation plus fort. Le calcul des spectres IR de ces structures sera réalisé dans le futur. Pour obtenir des spectres expérimentaux de nanoparticules hydrocarbonées en phase gaseuse, le développement du spectromètre en émission IR FIREFLY a été poursuivi et FIREFLY a été couplé avec une source de nanoparticules. Ces développements permettront bientôt de mesurer les spectres expérimentaux des systèmes d’intérêtThe mid-IR emission of many lines of sight in the Interstellar Medium (ISM) displays Aromatic Infrared Bands (AIBs) commonly attributed to Polycyclic Aromatic Hydrocarbons (PAHs). Identifying AIB carriers would allow for a clearer view of carbon matter evolution in the ISM. We intend to compare AIBs with theoretically derived and expermentally obtained IR spectra of hydrocarbon nanoparticles. The work done here focused on the structural analysis of such systems. Disordered molecular systems containing 24 to 60 C-atoms are generated by multi-tempering Monte Carlo simulations using the empirical potential AIREBO. After quenching the potential energy, the created structures are characterized with various order parameters. The evolution of the structural organization is analyzed as a function size and chemical composition (C/H ratio) of the systems. Generated structures display a great diversity, The statistical study of the order parameters shows tendancies. The global shape of the clusters depends on their size. H-atoms, often found on the edges of cage-like structures, favour a higher degree of organization. The calculation of IR spectra for those structures will be done in the future. To obtain experimental spectra of gas-phase hydrocarbon nanoparticles, the development of the IR emission spectrometer FIREFLY was continued. FIREFLY was coupled with a source of nanoparticles. Thoses developments will soon allow to measure experimental spectra of the molecular systems of interest
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Pana, Cristina. "Development of new carbon hybrid materials for Li+ and Na+ ion batteries applications." Thesis, Mulhouse, 2018. http://www.theses.fr/2018MULH0541.
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Au cours des dernières années, de nombreuses recherches se sont concentrées sur les batteries afin de satisfaire leur demande croissante pour de nombreuses applications. Les matériaux hybrides métal/carbone ont fait l'objet d'une grande attention en tant qu'anodes pour les batteries ioniques Li et Na en raison de leur capacité plus élevée par rapport aux anodes graphite/carbone dur. Cependant, l'expansion de la taille des NPs métalliques et la forte capacité irréversible pendant le 1ercycle sont les principaux inconvénients à surmonter et représentent l'objectif principal de cette thèse. Trois types d'hybrides ont été étudiés (C@Sn et C@SiO2pour les LIBs, et C@Sb pour les NIBs) et des voies de synthèse originales ont été développées qui ont permis d'obtenir des matériaux avec des NPs petites et homogènes distribuées dans le réseau de carbone. Plusieurs paramètres expérimentaux ont été optimisés, conduisant à une vaste palette de matériaux avec des porosités, des structures et des granulométries différentes. La température et la charge de particules se sont avérées être les principaux paramètres affectant la porosité et la taille des particules ainsi que les performances électrochimiques. L'augmentation de la température et de la charge de NPs ont conduit à une porosité plus faible qui a permis de diminuer la capacité irréversible et d'améliorer la capacité réversible. En même temps, le cycle à long terme a été affecté négativement en raison de la formation de particules non confinées et agglomérées. Un compromis entre la charge de carbone/porosité/structure a été déterminé pour chaque système et les mécanismes électrochimiques traités sur la base d'analyses post-mortemDuring the last years a lot of research has been focused on batteries to satisfy their increasing demand for a broad application. Metal-based/carbon hybrid materials received great attention as anodes for Li and Na ion batteries due to their higher capacity compared to graphite/hard carbons anodes. However, the metal particle size expansion and the high irreversible capacity during cycling are the main inconvenients to be overcome and represent the main goal of this thesis. Three type of hybrids were studied(C@Sn and C@SiO2for LIBs, and C@Sb for NIBs) and original synthesis pathways were developed which allowed to obtain materials with small and homogeneous distributed particles in the carbon network. Several experimental parameters were tuned leading to a large pallet of materials exhibiting different porosities, structures and particle size/distribution. The temperature and the particle loading were found to be the main parameters affecting the porosity and the particle size and further the electrochemical performances. The increase of both temperature and particle loading lead to smaller porosity which successfully allowed to diminish the irreversible capacity and to improve the reversible capacity. In the same time, the long-term cycling was negatively affected due to the formation of un-confined and agglomerated particles. The extent of particle agglomeration and consequently of capacity fading was found to depend on the type of metal and synthesis route. A compromise between the carbon loading/porosity/structure was determined for each system and the electrochemical mechanisms addressed based on post-mortem analyses
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Louisia, Stéphane. "Synthèse de catalyseurs bimétalliques supportés sur nanotubes de carbone dopés pour pile à combustible PEM." Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/17815/7/louisia.pdf.
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Les recherches menées dans le domaine des piles à combustibles à membrane échangeuse de protons (PEMFCs) depuis le début des années 1980 ont permis de considérablement améliorer leurs performances. Deux principaux verrous persistent néanmoins au niveau des catalyseurs : le coût et la stabilité. En effet, pour obtenir de bonnes performances, il faut que la couche active cathodique soit relativement chargée en métaux nobles, comme le platine, ce qui a un coût important. En plus d’être couteux, les catalyseurs utilisés commercialement sont sujets à différents phénomènes de dégradation, notamment l’oxydation du support carboné. Les travaux décrits dans cette thèse visent à produire des catalyseurs bimétalliques supportés sur des nanotubes de carbones dopés, afin de préparer des structures actives pour la Réaction de Réduction de l’Oxygène (ORR) et résistantes dans les conditions de fonctionnement des PEMFCs. La première étape a été la synthèse de nanotubes de carbone dopés à l’azote (N-CNT) ou au soufre (S-CNT). Différents traitements et fonctionnalisations ont été testés pour faciliter le dépôt et la dispersion de nanoparticules métalliques à la surface des nanotubes, faciliter l’intégration du catalyseur dans la couche active et ralentir le phénomène d’oxydation du carbone. Des nanoparticules bimétalliques PtCo et PtNi ont été préparées en utilisant une méthode de synthèse originale utilisant un liquide ionique comme stabilisant. Tous les catalyseurs ainsi synthétisés ont présenté des surfaces électro-actives (ECSA) élevées et de bonnes activités pour l’ORR. Les plus pertinents ont été étudiés en mono-cellules de 25 cm². Ils présentent de meilleurs résultats aux tests de dégradation accélérés du support carboné, comparés à une référence commercial PtCo supporté sur noir de carbone. Une diminution du chargement en platine de la couche active cathodique de 0,4 mgPt/cm² à 0,2 mgPt/cm² a permis d’améliorer les performances de la mono-cellule en diminuant notamment les limitations dûes au transport de matière dans la couche active.
Books on the topic "Carbonic nanoparticles"
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(Pharmacist), Montanari Stefano, ed. Nanopathology: The health impact of nanoparticles. Singapore: Pan Stanford Pub., 2008.
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Kenneth, Donaldson. The toxicology of carbon nanotubes. New York: Cambridge University Press, 2012.
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Carbon Nanotubes and Nanoparticles. Taylor & Francis Group, 2021.
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Carbon Nanotubes and Nanoparticles. Taylor & Francis Group, 2019.
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Haghi, A. K., Soney C. George, Miguel A. Esteso, Ana Cristina Faria Ribeiro, and Ann Rose Abraham. Optical and Molecular Physics: Theoretical Principles and Experimental Methods. Apple Academic Press, Incorporated, 2021.
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Haghi, A. K., Soney C. George, Miguel A. Esteso, Ana Cristina Faria Ribeiro, and Ann Rose Abraham. Optical and Molecular Physics: Theoretical Principles and Experimental Methods. Apple Academic Press, Incorporated, 2021.
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Haghi, A. K., Soney C. George, Miguel A. Esteso, Ana Cristina Faria Ribeiro, and Ann Rose Abraham. Optical and Molecular Physics. Taylor & Francis Group, 2021.
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Optical and Molecular Physics: Theoretical Principles and Experimental Methods. Apple Academic Press, Incorporated, 2021.
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Optical and Molecular Physics: Theoretical Principles and Experimental Methods. Apple Academic Press, Incorporated, 2023.
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Kodolov, Vladimir I., A. K. Haghi, Suresh C. Ameta, and Alexander V. Vakhrushev. Carbon Nanotubes and Nanoparticles: Current and Potential Applications. Apple Academic Press, Incorporated, 2019.
Find full textBook chapters on the topic "Carbonic nanoparticles"
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Manera, M. G., A. Colombelli, D. Lospinoso, S. Rella, and R. Rella. "Suitably Functionalised Gold Nanoparticles as Heavy Metals Sensors Transducers Based on Carbonic Anhydras." In Lecture Notes in Electrical Engineering, 138–46. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08136-1_22.
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Aguiló-Aguayo, Noemí, and Zhenyu Liu. "Carbon-Coated Nanoparticles." In Carbon Nanomaterials Sourcebook, 401–28. Boca Raton : Taylor & Francis Group, 2016. | “A CRC title.” |: CRC Press, 2018. http://dx.doi.org/10.1201/9781315371337-18.
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Schrand, Amanda M., Jay Johnson, Liming Dai, Saber M. Hussain, John J. Schlager, Lin Zhu, Yiling Hong, and Eiji Ōsawa. "Cytotoxicity and Genotoxicity of Carbon Nanomaterials." In Safety of Nanoparticles, 159–87. New York, NY: Springer New York, 2008. http://dx.doi.org/10.1007/978-0-387-78608-7_8.
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Arnault, J. C. "Nanodiamonds: From Synthesis and Purification to Deposition Techniques, Hybrids Fabrication and Applications." In Carbon Nanoparticles and Nanostructures, 1–45. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_1.
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Coffinier, Yannick, Rabah Boukherroub, and Sabine Szunerits. "Carbon-Based Nanostructures for Matrix-Free Mass Spectrometry." In Carbon Nanoparticles and Nanostructures, 331–56. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_10.
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Ma, Yao, Nianjun Yang, and Xin Jiang. "One-Dimensional Carbon Nanostructures: Low-Temperature Chemical Vapor Synthesis and Applications." In Carbon Nanoparticles and Nanostructures, 47–76. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_2.
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Zhang, Minfang, and Masako Yudasaka. "Carbon Nanohorns and Their High Potential in Biological Applications." In Carbon Nanoparticles and Nanostructures, 77–107. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_3.
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Hui, Yuen Yung, Chi-An Cheng, Oliver Y. Chen, and Huan-Cheng Chang. "Bioimaging and Quantum Sensing Using NV Centers in Diamond Nanoparticles." In Carbon Nanoparticles and Nanostructures, 109–37. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_4.
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Komatsu, Naoki, and Li Zhao. "Polyglycerol-Functionalized Nanoparticles for Biomedical Imaging." In Carbon Nanoparticles and Nanostructures, 139–59. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_5.
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Dong, Yongqiang, Jianhua Cai, and Yuwu Chi. "Carbon Based Dots and Their Luminescent Properties and Analytical Applications." In Carbon Nanoparticles and Nanostructures, 161–238. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28782-9_6.
Full textConference papers on the topic "Carbonic nanoparticles"
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Raj, Navneet, and T. Varun Pal. "Enhancing Efficiency of HCl Based Stimulating Fluids by Creating In-Situ Carbonic Acid Using Nickel Nanoparticles." In International Petroleum Technology Conference. International Petroleum Technology Conference, 2014. http://dx.doi.org/10.2523/iptc-17814-ms.
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Zhu, Youyi, Peng Yu, and Jian Fan. "Study on Nanoparticle Stabilized Emulsions for Chemical Flooding Enhanced Oil Recovery." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21456-ms.
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Abstract Chemical flooding is one of enhanced oil recovery (EOR) methods. The primary mechanism of EOR of chemical flooding is interfacial tension reduction, mobility ratio improvement and wettability changes. Recent studies showed that enhancing emulsification performance was beneficial to improve oil displacement efficiency. The formation of Pickering emulsion by nanoparticles could greatly improve the emulsifying performance. Using nanoparticles stabilized emulsions for chemical EOR application is a novel method. In this study, six different types of nanoparticles were selected, including hydrophilic nano silica, modified nano silica, carbon nanotubes and bentonite, etc. The nanoparticle combine with petroleum sulfonate could form a stable emulsion. Particle wettability were measured by using contact angle measurement (OCA20). Emulsifying intensity index was measured for different nanoparticle-stabilized emulsions. The mechanisms of nanoparticle-stabilized emulsions and relationship between emulsion stability have been investigated. The influence of dispersant on nanoparticle-stabilized emulsions also has been investigated. Nanoparticles mainly play a role in improving the stability of emulsions while surfactant play a major role in enhancing the emulsifying dispersion. The wettability of solid particles was one of the most important factors that affects the stability of emulsions. Partial hydrophobic nanoparticles were much easier to form stable emulsions than hydrophilic nanoparticles. Nanoparticles could form a three-dimensional network structure, thereby the stability of the emulsion was improved. Use of surfactant to disperse nanoparticles could further improve the emulsion stability. Finally, three nanoparticles stabilized emulsion formulations were developed for chemical flooding EOR. Nanoparticle-stabilized emulsions could improve oil displacement efficiency in chemical combination flooding. This research was used to optimize chemical combination flooding formulation and has a guidance function for application of nanoparticles in chemical flooding EOR.
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Hosseini, Mahmoud Reza, and Nader Jalili. "Molecular Dynamics Investigation of Carbon Diffusivity in Metal Nanoparticles During CVD-Based Nanotube Fabrication Process." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15222.
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In this paper, molecular dynamics technique is utilized to investigate carbon molecules diffusivity into iron oxide nanoparticles such as FeO and Fe2O3. Such nanoparticles can be used during carbon nanotube (CNT) synthesis process in a chemical vapor deposition (CVD) system. Several simulations are conducted in the atmospheric pressure condition and for different temperatures ranging from 500 to 1100°C, which is common range for multi-walled and single-walled CNT (MWCNT and SWCNT) fabrication. The mean square displacement (MSD) diagrams and their corresponding diffusivity of the carbon molecules into the nanoparticles are then plotted. The results are compared with those obtained after adding silicon molecular structure to the each nanoparticle as substrate. The results From NPT/NVE (pressure constant-temperature constant/velocity constant-energy constant) simulations show that for each nanoparticle, the diffusivity increases as higher temperatures considered in the simulation. However, the corresponding diffusivity rate doesn't necessarily increase. In the diffusivity diagrams, three distinctive temperature regions are observed. In the temperature regions where MWCNT and SWCNT are commonly produced, decreasing in diffusivity rate is observed, while in transition region where CNTs change from multi-walled to single-walled, the diffusivity increases for both simulated metal nanoparticles. Finally, by investigating and comparing diffusivity diagrams of each nanoparticle, before and after adding silicon as substrate, it is observed that the effects of silicon layer decreases the amount of carbon molecules diffusivity. This decrease is more considerable in higher temperatures. The obtained information from this study helps to understand the growth rate and formation mechanism of MWCNT/SWCNT and their relationship with carbon diffusivity in metal nanoparticles in great detail which are important keys in controlling nanotube properties.
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Alfakher, Ahmad M., and David A. DiCarlo. "Reduced Carbon Dioxide Mobility in Experimental Core Flood Using Surface Coated Silica Nanoparticles as a Foaming Agent." In Offshore Technology Conference. OTC, 2023. http://dx.doi.org/10.4043/32382-ms.
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Abstract Carbon dioxide (CO2) is the most used solvent in enhanced oil recovery (EOR), as it can have a high displacement efficiency in favorable conditions. Its disadvantages are relatively low sweep efficiencies caused by a viscosity and density that is lower than the fluid it displaces. Surface-coated silica nanoparticles create in-situ CO2 foam, which has a more favorable mobility ratio and therefore better sweep. These nanoparticles can also be used in carbon capture and storage (CCS) applications in injecting CO2 foam into brine aquifers. This paper presents the results of core flood experiments that aimed to study surface coated silica nanoparticles as an in-situ CO2 foaming agent. In these experiments, pressure drop was measured across the core as a whole and in five individual sections. The core was placed vertically, and liquid CO2 was pumped at the top of the core. Surface coated silica nanoparticles suspended in the brine is used in some of the floods and compared to a control flood that had no nanoparticles. In these experiments, pressure drops in nanoparticle cases were a multiple of 5-10 those in the control cases. In addition, total core pressure drops in nanoparticle cases increased as the core got more saturated with CO2, and the increase was observed sequentially in each section as it got invaded by CO2.The mobility of CO2 was reduced by an order of magnitude on average compared to the control. The CO2 moved slower through the core and breakthrough was delayed in the nanoparticle case. The study provides quantitative nanoparticle CO2foam mobility measurements and calculations, compared to those in control cases. Properties calculated from this study can be used to improve both EOR and CCS applications of CO2 flooding by scaling the results to the reservoir scale.
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Cody, Jonathan W., and Sungwon S. Kim. "Effects of Annealing Parameters on Nickel Catalyst Nanoparticle Size for Carbon Nanotube Synthesis Applications." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65514.
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The properties of carbon nanotubes are dependent, in part, on the size of the catalyst metal nanoparticles from which the carbon nanotubes are grown. Annealing is a common technique for forming the catalyst nanoparticles from deposited films. While there is ample work connecting catalyst film properties or catalyst nanoparticle properties to carbon nanotube growth outcomes, the control of catalyst nanoparticle size by means other than the variation of initial film thickness is less explored. This work develops an empirical correlation for the control of nickel nanoparticle equivalent diameter by modification of anneal plateau temperature and anneal plateau time, thereby providing an additional avenue of control for catalyst properties. It has been hypothesized that the size of catalyst nanoparticles can be predetermined by appropriate selection of the initial catalyst film thickness, plateau temperature, and plateau time of the annealing process. To this end, buffer layers of 50 nm titanium, followed by 20 nm aluminum, were deposited onto silicon substrates via electron beam evaporation. Nickel catalyst layers were then deposited with thicknesses of either 5, 10, or 20 nm. Samples of each of the three nickel layer thicknesses were annealed in an ambient air environment at different combinations of 500, 600, 700, 800, and 900 °C plateau temperature and 5, 10, and 15 minute plateau time. Representative time-temperature curves corresponding to each plateau temperature were also acquired. The end result was a set of 45 samples, each with a unique combination of initial nickel film thickness, anneal plateau temperature, and anneal plateau time. Resulting nanoparticles were characterized by atomic force microscopy, and distributions of nanoparticle equivalent diameter were collected via a watershed algorithm implemented by the Gwyddion software package. Comparison of the 45 parameter combinations revealed a wide range of nanoparticle sizes. In most cases, comparable equivalent diameters were obtained from a variety of parameter combinations. Thus, results provide multiple options for achieving the same nanoparticle diameter, for use in cases where additional restraints are present. To facilitate such decisions, a correlation was developed that connected catalyst nanoparticle diameter to the three process parameters of initial catalyst film thickness, anneal plateau temperature, and anneal plateau time. For example, a given initial Ni film thickness can be annealed to a specified nanoparticle size by selecting anneal plateau temperature and plateau time per the correlation, provided that comparable buffer layers were chosen. This correlation provides a more robust array of options for specification of catalyst nanoparticle size and final carbon nanotube properties for a specific application.
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Chen, J. Y., J. Cho, and I. M. Daniel. "Processing and Characterization of Carbon Fiber/Epoxy Composites Reinforced With Graphite Nanoplatelets." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41212.
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The epoxy matrix in carbon fiber/epoxy composites was modified with graphite nanoplatelets to improve the matrix dominated mechanical properties of the composite. A prepreg-autoclave process was developed for preparation of nanoparticle-reinforced fiber composites. The in-plane shear modulus and longitudinal compressive strength were enhanced. The compressive strength of the composite was increased by 43% and 44%, and the in-plane shear modulus was improved by 7% and 15% for 3 wt% and 5 wt% of nanoparticle loadings, respectively. This mechanical enhancement is mainly attributed to the reinforcement of matrix phase by the nanoparticles. However, the substantially improved compressive strength is attributed in large part to the reduced waviness of the fibers in the uni-weave perform caused by the nanoparticles between layers.
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Hess, Kieran, and Amy S. Fleischer. "The Influence of Nanoparticle Type on the Viscosity of Nanoenhanced Energy Storage Materials." In ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ipack2015-48082.
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The use of nanoparticles to improve the thermal properties of low thermal conductivity phase change materials is of significant interest. However, the addition of nanoparticles to a base fluid is known to result in an increase in viscosity. An increase in viscosity can suppress convective currents, reducing overall heat transfer thus it necessary to quantify the impact of nanoparticle addition on the viscosity of a PCM. In this work nanoparticle enhanced phase change mateirals are synthesized using paraffin and three different types of nanoparticles: exfoliated graphite nanoplatelets (xGNP), multi-walled carbon nanotubes (MWCNT) and herringbone graphite nanofibers (HGNF). The particles are loaded at rates between 0.0024wt% to 0.1wt%. The viscosity is analyzed at temperatures between 60 and 100°C. The influence of temperature, nanoparticle type and nanoparticle loading level on viscosity are presented and discussed. The results show that for xGNP and HGNF within the operating condition studied here that there is no impact of the nanoparticle addition on the viscosity of the base material. However, the addition of MWCNT is found to increase the viscosity of the base fluid with the impact increasing with loading level.
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Zhou, Yingke, Robert Pasquarelli, Joe Berry, David Ginley, and Ryan O’Hayre. "Improving PEM Fuel Cell Catalysts Using Nitrogen-Doped Carbon Supports." In ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/fuelcell2008-65172.
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This study experimentally examines the effect of nitrogen doping on the activity of Pt/C catalyst systems. The investigation was accomplished through the development of geometrically well-defined model catalytic systems consisting of tunable assemblies of Pt catalyst nanoparticles deposited onto both N-doped and undoped highly-oriented pyrolytic graphite (HOPG) substrates. N-doping was achieved via ion beam implantation, and Pt was electrodeposited from solutions of H2PtCl6 in aqueous HClO4. Morphology from scanning electron microscopy (SEM) and catalytic activity measurement from aqueous electrochemical analysis were utilized to examine the N-doping effects. The results strongly support the theory that doping nitrogen into a graphite support significantly affects both the morphology and behavior of the overlying Pt nanoparticles. In particular, nitrogen-doping was observed to cause a significant decrease in the average Pt nanoparticle size, an increase in the Pt nanoparticle dispersion, and a significant increase in catalytic activity for both methanol oxidation and oxygen reduction.
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Mahdi, Tanjheel H., Mohammad E. Islam, Mahesh V. Hosur, Alfred Tcherbi-Narteh, and S. Jeelani. "Characterization of Mechanical and Viscoelastic Properties of SC-15 Epoxy Nanocomposites Reinforced With Multi-Walled Carbon Nanotubes, Nanoclay and Binary Nanoparticles." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36176.
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Mechanical and viscoelastic properties of polymer nanocomposites reinforced with carboxyl functionalized multiwalled carbon nanotubes (COOH-MWCNT), montmorillonite nanoclays (MMT) and MWCNT/MMT binary nanoparticle were investigated. In this study, 0.3 wt. % of COOH-MWCNT, 2 wt. % of MMT and 0.1 wt. % COOH-MWCNT/2 wt. % MMT binary nanoparticles by weight of epoxy were incorporated to modify SC-15 epoxy resin system. The nanocomposites were subjected to flexure test, dynamic mechanical and thermomechanical analyses. Morphological study was conducted with scanning electron microscope. Addition of each of the nanoparticles in epoxy showed significant improvement in mechanical and viscoelastic properties compared to those of control ones. But, best results were obtained for addition of 0.1% MWCNT/2% MMT binary nanoparticles in epoxy. Nanocomposites modified with binary nanoparticles exhibited about 20% increase in storage modulus as well as 25° C increase in glass transition temperature. Flexural modulus for binary nanoparticle modified composites depicted about 30% improvement compared to control ones. Thus, improvement of mechanical and viscoelastic properties was achieved by incorporating binary nanoparticles to epoxy nanocomposites. The increase in properties was attributed to synergistic effect of MWCNTs and nanoclay in chemically interacting with each other and epoxy resin as well as in arresting and delaying the crack growth once initiated.
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O’Hayre, Ryan, Yingke Zhou, Robert Pasquarelli, Joe Berry, and David Ginley. "Enhancement of Pt-Based Catalysts via N-Doped Carbon Supports." In ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53078.
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This study experimentally examines the enhancement of carbon supported Pt-based catalysts systems via nitrogen doping. It has been reported that nitrogen-containing carbons promote significant enhancement in Pt/C catalyst activity and durability with respect to the methanol oxidation and oxygen reduction reactions. In order to systematically investigate the effect of N-doping, in this work we have developed geometrically well-defined model catalytic systems consisting of tunable assemblies of Pt catalyst nanoparticles deposited onto both N-doped and undoped highly-oriented pyrolytic graphite (HOPG) substrates. N-doping was achieved via ion beam implantation, and Pt was electrodeposited from solutions of H2PtCl6 in aqueous HClO4. Morphology from scanning electron microscopy (SEM) and catalytic activity measurement from aqueous electrochemical analysis were utilized to examine the N-doping effects. The results strongly support the theory that doping nitrogen into a graphite support significantly affects both the morphology and behavior of the overlying Pt nanoparticles. In particular, nitrogen-doping was observed to cause a significant decrease in the average Pt nanoparticle size, an increase in the Pt nanoparticle dispersion, and a significant increase in catalytic activity for both methanol oxidation and oxygen reduction.
Reports on the topic "Carbonic nanoparticles"
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Chefetz, Benny, Baoshan Xing, and Yona Chen. Interactions of engineered nanoparticles with dissolved organic matter (DOM) and organic contaminants in water. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7699863.bard.
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Background: Engineered carbon nanotubes (CNTs) are expected to be increasingly released into the environment with the rapid increase in their production and use. The discharged CNTs may interact with coexisting contaminants and subsequently change environmental behaviors and ecological effects of both the CNTs themselves and the contaminants. Dissolved organic matter (DOM) plays a critical role in the transport of CNTs in the aquatic environment, affecting both CNT's surface properties through adsorption, and its colloidal stability in solution. Therefore, CNT-bound DOM complexes may interact with coexisting contaminants, thus affecting their environmental fate. With increasing production and use of CNTs, there is an increasing risk that humans could be exposed to CNTs mainly through ingestion and inhalation. Since CNTs can be carriers of contaminants due to their high adsorption affinity and capacity, the distribution of these nanoparticles in the environment holds a potential environmental and health risk. Project objectives: The overall goal of this project was to gain a better understanding of the environmental behavior of engineered nanoparticles with DOM and organic pollutant in aqueous systems. The scope of this study includes: characterizing various types of engineered nanoparticles and their interaction with DOM; binding studies of organic contaminants by nanoparticles and DOM-nanoparticle complexes; and examining interactions in DOM-nanoparticles-contaminant systems. Major conclusions, solutions and achievements: DOM has a pronounced effect on colloidal stability of CNTs in solution and on their surface chemistry and reactivity toward associated contaminants. The structure and chemical makeup of both CNTs and DOM determine their interactions and nature of formed complexes. CNTs, contaminants and DOM can co-occur in the aquatic environment. The occurrence of co-contaminants, as well as of co-introduction of DOM, was found to suppress the adsorption of organic contaminants to CNTs through both competition over adsorption sites and direct interactions in solution. Furthermore, the release of residual contaminants from CNTs could be enhanced by biomolecules found in the digestive as well as the respiratory tracts, thus increasing the bioaccessibility of adsorbed contaminants and possibly the overall toxicity of contaminant-associated CNTs. Contaminant desorption could be promoted by both solubilization and sorptive competition by biological surfactants. Scientific and agricultural implications: The information gained in the current project may assist in predicting the transport and fate of both CNTs and associated contaminants in the natural environment. Furthermore, the results imply a serious health risk from contaminant-associated CNTs.
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Lu, Dengwei, Enjie Tang, Supeng Yin, Yizeng Sun, Yuquan Yuan, Tingjie Yin, Zeyu Yang, and Fan Zhang. Intraoperative strategies in identification and functional protection of parathyroid gland for patients with thyroidectomy: A network meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, November 2022. http://dx.doi.org/10.37766/inplasy2022.11.0109.
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Review question / Objective: To assess the roles of intraoperative visualization of parathyroid glands (IVPG) strategies including autofluorescence (AF), indocyanine green (ICG) fluorescence and carbon nanoparticles (CN) in identification and functional protection of parathyroid glands (PGs). Condition being studied: The IVPG strategy is essential for intraoperative identification and functional protection of PGs in patients undergoing thyroid surgery. Recent studies have revealed that autofluorescence (AF), indocyanine green (ICG) fluorescence, and carbon nanoparticles (CN) contribute to reducing the incidence of postoperative hypocalcemia by improving PGs identification(6-8). However, different IVPGs have respective superiority and inferiority in clinical application. Thus, this network meta-analysis aimed to systematically analyze the significance of IVPG strategy in identifying PGs and protecting their function.
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Tse, Stephen D. Encapsulating Reactive Nanoparticles in Carbon Nanotubes Using Flame-Based Synthesis. Fort Belvoir, VA: Defense Technical Information Center, December 2008. http://dx.doi.org/10.21236/ada500573.
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Michelsen, Hope A., Peter O. Witze, and Thomas B. Settersten. Development of detection techniques and diagnostics for airborne carbon nanoparticles. Office of Scientific and Technical Information (OSTI), November 2003. http://dx.doi.org/10.2172/918338.
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Michelsen, Hope Andrea. Development of Detection Techniques and Diagnostics for Airborne Carbon Nanoparticles. Office of Scientific and Technical Information (OSTI), November 2003. http://dx.doi.org/10.2172/820205.
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Meduri, Kavita. Carbon-Supported Transition Metal Nanoparticles for Catalytic and Electromagnetic Applications. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.6523.
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Panchapakesan, Balaji. Applications of Nanoparticles/Nanowires and Carbon Nanotubes for Breast Cancer Research. Fort Belvoir, VA: Defense Technical Information Center, September 2004. http://dx.doi.org/10.21236/ada431597.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova, and Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.
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Ivanova, Radostina, Momtchil Dimotrov, Daniela Kovacheva, Boyko Tsyntsarski, Ivanka Spassova, Nikolay Velinov, Daniela Paneva, and Tanya Tsoncheva. Zinc Ferrite Nanoparticles Hosted in Activated Carbon from Waste Biomass as Catalyst for Methanol Decomposition. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, March 2021. http://dx.doi.org/10.7546/crabs.2021.03.05.
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Wongpakdeea, Thinnapong, Karin Crenshaw, Hery Figueroa Wong, Duangjai Nacapricha, and Bruce McCord. Advancements in Analytical Techniques for Rapid Identification of Gunshot Residue and Low Explosives through Electrochemical Detection and Surface-Enhanced Raman Spectroscopy. Florida International University, 2024. https://doi.org/10.25148/gfjcsr.2024.7.
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This research focuses on developing two analytical methods for forensic investigations using electrochemical detection and surface-enhanced Raman spectroscopy. For electrochemical analysis, screen-printed carbon electrodes are used to detect metals and nitrate/nitrite compounds commonly found in gunshot residue. Gold electrodeposition and copper modification enhance sensitivity and catalytic activity, respectively. Additionally, a screen-printed gold electrode modified with gold nanoparticles enables surface-enhanced Raman spectroscopy, requiring only a single drop of sample solution. Testing includes various compounds relevant to forensic identification, with Origin software used for data analysis. These techniques provide rapid and precise onsite examination of gunshot residue and low explosives, eliminating the need for benchtop instruments. Overall, these advancements enhance forensic inquiries and contribute to the ongoing progress of forensic science, aiding law enforcement agencies worldwide in seeking justice.