WorldWideScience

Sample records for monodisperse nanoscale inorganic

  1. Organic inorganic hybrid coating (poly(methyl methacrylate)/monodisperse silica)

    Science.gov (United States)

    Rubio, E.; Almaral, J.; Ramírez-Bon, R.; Castaño, V.; Rodríguez, V.

    2005-04-01

    Polymethylmethacrylate-silica hybrid coatings were prepared from methyl methacrylate and monodisperse colloidal silica prepared by the Stöber method. The surfaces of the spheres were successfully modified by chemical reaction with 3-(trimethoxysilyl) propyl methacrylate (TMSPM) to compatibilise the organic and inorganic components of the precursor solution mixture. The coatings were deposited by dip-coating on glass substrates. They result with good properties of homogeneity, optical transparence, hardness and adhesion.

  2. Nanoscale Organic−Inorganic Hybrid Lubricants

    KAUST Repository

    Kim, Daniel; Archer, Lynden A.

    2011-01-01

    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona

  3. Nanoscale Organic−Inorganic Hybrid Lubricants

    KAUST Repository

    Kim, Daniel

    2011-03-15

    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona brush that stabilizes them against aggregation. When these hybrid particles are dispersed in poly-α-olefin (PAO) oligomers, they form homogeneous nanocomposite fluids at both low and high particle loadings. By varying the volume fraction of the SiO2 nanostructures in the PAO nanocomposites, we show that exceptionally stable hybrid lubricants can be created and that their mechanical properties can be tuned to span the spectrum from simple liquids to complex gels. We further show that these hybrid lubricants simultaneously exhibit lower interfacial friction coefficients, enhanced wear and mechanical properties, and superior thermal stability in comparison with either PAO or its nanocomposites created at low nanoparticle loadings. Profilometry and energy dispersive X-ray spectroscopic analysis of the wear track show that the enhanced wear characteristics in PAO-SiO2 composite lubricants originate from two sources: localization of the SiO2 particles into the wear track and extension of the elastohydrodynamic lubrication regime to Sommerfeld numbers more than an order of magnitude larger than for PAO. © 2011 American Chemical Society.

  4. Self-Templated Stepwise Synthesis of Monodispersed Nanoscale Metalated Covalent Organic Polymers for In Vivo Bioimaging and Photothermal Therapy.

    Science.gov (United States)

    Shi, Yanshu; Deng, Xiaoran; Bao, Shouxin; Liu, Bei; Liu, Bin; Ma, Ping'an; Cheng, Ziyong; Pang, Maolin; Lin, Jun

    2017-09-05

    Size- and shape-controlled growth of nanoscale microporous organic polymers (MOPs) is a big challenge scientists are confronted with; meanwhile, rendering these materials for in vivo biomedical applications is still scarce. In this study, a monodispersed nanometalated covalent organic polymer (MCOP, M=Fe, Gd) with sizes around 120 nm was prepared by a self-templated two-step solution-phase synthesis method. The metal ions (Fe 3+ , Gd 3+ ) played important roles in generating a small particle size and in the functionalization of the products during the reaction with p-phenylenediamine (Pa). The resultant Fe-Pa complex was used as a template for the subsequent formation of MCOP following the Schiff base reaction with 1,3,5-triformylphloroglucinol (Tp). A high tumor suppression efficiency for this Pa-based COP is reported for the first time. This study demonstrates the potential use of MCOP as a photothermal agent for photothermal therapy (PTT) and also provides an alternative route to fabricate nano-sized MCOPs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Charge transport in nanoscale "all-inorganic" networks of semiconductor nanorods linked by metal domains.

    Science.gov (United States)

    Lavieville, Romain; Zhang, Yang; Casu, Alberto; Genovese, Alessandro; Manna, Liberato; Di Fabrizio, Enzo; Krahne, Roman

    2012-04-24

    Charge transport across metal-semiconductor interfaces at the nanoscale is a crucial issue in nanoelectronics. Chains of semiconductor nanorods linked by Au particles represent an ideal model system in this respect, because the metal-semiconductor interface is an intrinsic feature of the nanosystem and does not manifest solely as the contact to the macroscopic external electrodes. Here we investigate charge transport mechanisms in all-inorganic hybrid metal-semiconductor networks fabricated via self-assembly in solution, in which CdSe nanorods were linked to each other by Au nanoparticles. Thermal annealing of our devices changed the morphology of the networks and resulted in the removal of small Au domains that were present on the lateral nanorod facets, and in ripening of the Au nanoparticles in the nanorod junctions with more homogeneous metal-semiconductor interfaces. In such thermally annealed devices the voltage dependence of the current at room temperature can be well described by a Schottky barrier lowering at a metal semiconductor contact under reverse bias, if the spherical shape of the gold nanoparticles is considered. In this case the natural logarithm of the current does not follow the square-root dependence of the voltage as in the bulk, but that of V(2/3). From our fitting with this model we extract the effective permittivity that agrees well with theoretical predictions for the permittivity near the surface of CdSe nanorods. Furthermore, the annealing improved the network conductance at cryogenic temperatures, which could be related to the reduction of the number of trap states.

  6. Highly Selective Synthesis of Catalytically Active Monodisperse Rhodium Nanocubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Grass, M.E.; Kuhn, J.N.; Tao, F.; Habas, S.E.; Huang, W.; Yang, P.; Somorjai, G.A.

    2009-02-21

    Synthesis of monodisperse and shape-controlled colloidal inorganic nanocrystals (NCs) is of increasing scientific interest and technological significance. Recently, shape control of Pt, Pd, Ag, Au, and Rh NCs has been obtained by tuning growth kinetics in various solution-phase approaches, including modified polyol methods, seeded growth by polyol reduction, thermolysis of organometallics, and micelle techniques. Control of reduction kinetics of the noble metal precursors and regulation of the relative growth rates of low-index planes (i.e. {l_brace}100{r_brace} and {l_brace}111{r_brace}) via selective adsorption of selected chemical species are two keys for achieving shape modification of noble metal NCs. One application for noble metal NCs of well-defined shape is in understanding how NC faceting (determines which crystallographic planes are exposed) affects catalytic performance. Rh NCs are used in many catalytic reactions, including hydrogenation, hydroformylation, hydrocarbonylation, and combustion reactions. Shape manipulation of Rh NCs may be important in understanding how faceting on the nanoscale affects catalytic properties, but such control is challenging and there are fewer reports on the shape control of Rh NCs compared to other noble metals. Xia and coworkers obtained Rh multipods exhibiting interesting surface plasmonic properties by a polyol approach. The Somorjai and Tilley groups synthesized crystalline Rh multipods, cubes, horns and cuboctahedra, via polyol seeded growth. Son and colleagues prepared catalytically active monodisperse oleylamine-capped tetrahedral Rh NCs for the hydrogenation of arenes via an organometallic route. More recently, the Somorjai group synthesized sizetunable monodisperse Rh NCs using a one-step polyol technique. In this Communication, we report the highly selective synthesis of catalytically active, monodisperse Rh nanocubes of < 10 nm by a seedless polyol method. In this approach, Br{sup -} ions from trimethyl

  7. Recent advances in porous nanoparticles for drug delivery in antitumoral applications: inorganic nanoparticles and nanoscale metal-organic frameworks.

    Science.gov (United States)

    Baeza, Alejandro; Ruiz-Molina, Daniel; Vallet-Regí, María

    2017-06-01

    Nanotechnology has provided new tools for addressing unmet clinical situations, especially in the oncology field. The development of smart nanocarriers able to deliver chemotherapeutic agents specifically to the diseased cells and to release them in a controlled way has offered a paramount advantage over conventional therapy. Areas covered: Among the different types of nanoparticle that can be employed for this purpose, inorganic porous materials have received significant attention in the last decade due to their unique properties such as high loading capacity, chemical and physical robustness, low toxicity and easy and cheap production in the laboratory. This review discuss the recent advances performed in the application of porous inorganic and metal-organic materials for antitumoral therapy, paying special attention to the application of mesoporous silica, porous silicon and metal-organic nanoparticles. Expert opinion: The use of porous inorganic nanoparticles as drug carriers for cancer therapy has the potential to improve the life expectancy of the patients affected by this disease. However, much work is needed to overcome their drawbacks, which are aggravated by their hard nature, exploiting the advantages offered by highly the ordered pore network of these materials.

  8. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.; Moganty, Surya S.; Archer, Lynden A.

    2010-01-01

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Aerosol fabrication methods for monodisperse nanoparticles

    Science.gov (United States)

    Jiang, Xingmao; Brinker, C Jeffrey

    2014-10-21

    Exemplary embodiments provide materials and methods for forming monodisperse particles. In one embodiment, the monodisperse particles can be formed by first spraying a nanoparticle-containing dispersion into aerosol droplets and then heating the aerosol droplets in the presence of a shell precursor to form core-shell particles. By removing either the shell layer or the nanoparticle core of the core-shell particles, monodisperse nanoparticles can be formed.

  11. Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

    Science.gov (United States)

    Vincent, Abhilash

    Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

  12. Synthetic routes to a nanoscale inorganic cluster [Ga13(μ3-OH)6(μ2-OH)18(H2O)](NO3)15 evaluated by solid-state 71Ga NMR

    International Nuclear Information System (INIS)

    Hammann, Blake A.; Marsh, David A.; Ma, Zayd L.; Wood, Suzannah R.; Eric West, Michael; Johnson, Darren W.; Hayes, Sophia E.

    2016-01-01

    Solid-state 71 Ga NMR was used to characterize a series of [Ga 13 (μ 3 -OH) 6 (μ 2 -OH) 18 (H 2 O)](NO 3 ) 15 “Ga 13 ” molecular clusters synthesized by multiple methods. These molecular clusters are precursors to thin film electronics and may be employed in energy applications. The synthetic routes provide varying levels of impurities in the solid phase, and these impurities often elude traditional characterization techniques such as powder X-ray diffraction and Raman spectroscopy. Solid-state NMR can provide a window into the gallium species even in amorphous phases. This information is vital in order to prevent the impurities from causing defect sites in the corresponding thin films upon gelation and condensation (polymerization) of the Ga 13 clusters. This work demonstrates the resolving power of solid-state NMR to evaluate structure and synthetic quality in the solid state, and the application of high-field NMR to study quadrupolar species, such as 71 Ga. - Graphical abstract: The various synthetic routes and 71 Ga solid-state NMR spectra of the nanoscale inorganic cluster [Ga 13 (μ 3 -OH) 6 (μ 2 -OH) 18 (H 2 O)](NO 3 ) 15 . - Highlights: • Solid-state 71 Ga NMR of hydroxo-aquo metal clusters and the impurities present. • High-field NMR capability allows for quadrupolar species, such as 71 Ga, to be routinely studied. • Efficient and environmentally friendly synthetic routes have been developed to prepare hydroxo-aquo metal clusters.

  13. Design of monodisperse and well-defined polypeptide-based polyvalent inhibitors of anthrax toxin.

    Science.gov (United States)

    Patke, Sanket; Boggara, Mohan; Maheshwari, Ronak; Srivastava, Sunit K; Arha, Manish; Douaisi, Marc; Martin, Jacob T; Harvey, Ian B; Brier, Matthew; Rosen, Tania; Mogridge, Jeremy; Kane, Ravi S

    2014-07-28

    The design of polyvalent molecules, presenting multiple copies of a specific ligand, represents a promising strategy to inhibit pathogens and toxins. The ability to control independently the valency and the spacing between ligands would be valuable for elucidating structure-activity relationships and for designing potent polyvalent molecules. To that end, we designed monodisperse polypeptide-based polyvalent inhibitors of anthrax toxin in which multiple copies of an inhibitory toxin-binding peptide were separated by flexible peptide linkers. By tuning the valency and linker length, we designed polyvalent inhibitors that were over four orders of magnitude more potent than the corresponding monovalent ligands. This strategy for the rational design of monodisperse polyvalent molecules may not only be broadly applicable for the inhibition of toxins and pathogens, but also for controlling the nanoscale organization of cellular receptors to regulate signaling and the fate of stem cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Monodisperse Magneto-Fluorescent Bifunctional Nanoprobes for Bioapplications

    Science.gov (United States)

    Zhang, Hongwang; Huang, Heng; Pralle, Arnd; Zeng, Hao

    2013-03-01

    We present the work on the synthesis of dye-doped monodisperse Fe/SiO2 core/shell nanoparticles as bifunctional probes for bioapplications. Magnetic nanoparticles (NP) have been widely studied as nano-probes for bio-imaging, sensing as well as for cancer therapy. Among all the NPs, Fe NPs have been the focus because they have very high magnetization. However, Fe NPs are usually not stable in ambient due to the fast surface oxidation of the NPs. On the other hand, dye molecules have long been used as probes for bio-imaging. But they are sensitive to environmental conditions. It requires passivation for both so that they can be stable for applications. In this work, monodisperse Fe NPs with sizes ranging from 13-20 nm have been synthesized through the chemical thermal-decomposition in a solution. Silica shells were then coated on the Fe NPs by a two-phase oil-in-water method. Dye molecules were first bonded to a silica precursor and then encapsulated into the silica shell during the coating process. The silica shells protect both the Fe NPs and dye molecules, which makes them as robust probes. The dye doped Fe/SiO2 core/shell NPs remain both highly magnetic and highly fluorescent. The stable dye doped Fe/SiO2NPs have been used as a dual functional probe for both magnetic heating and local nanoscale temperature sending, and their performance will be reported. Research supported by NSF DMR 0547036, DMR1104994.

  15. Production of Monodisperse Nanoparticles and Application of Discrete-Monodisperse Model in Plasma Reactors

    International Nuclear Information System (INIS)

    Kim, Dong-Joo; Kim, Kyo-Seon; Zhao, Qian-Qiu

    2003-01-01

    The particle growth in plasma reactor were investigated by using the discrete-monodisperse (D-M) model for various process conditions. The monodisperse large sized particle distribution predicted by the D-M model are in good agreement with the large sized particles by the discrete-sectional model and also in the experiments by Shiratani et al. (1996). Some fractions of the small size particles are in a neutral state or even charged positively, but most of the large sized monodisperse particles are charged negatively. As the mass generation rate of monomers increases, the large sized particles grow more quickly and the production rate of nanoparticles of 100nm by plasma reactor increases. As the initial electron concentration or the monomer diameter increases, it takes longer time for the large sized particles to grow up to 100nm, but the large sized particle concentration of 100nm increases and the resulting production rate of large sized particles of 100nm increases. As the residence time increases, the time for the large sized particles to grow up to 100nm decreases and the large sized particle concentration of 100nm increases and, as a result, the production rate of large sized particles of 100nm increases. We propose that the plasma reactor can be a good candidate to produce monodisperse nanoparticles

  16. Progress in Preparation of Monodisperse Polymer Microspheres

    Science.gov (United States)

    Zhang, Hongyan

    2017-12-01

    The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

  17. Nanoscale chirality in metal and semiconductor nanoparticles.

    Science.gov (United States)

    Kumar, Jatish; Thomas, K George; Liz-Marzán, Luis M

    2016-10-18

    The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided.

  18. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The start-up and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 and 103 kg/mole, and for three bidisperse polystyrene melts. The monodisperse melts show a maximum in the steady elongational viscosity vs. the elongational...

  19. The Generation And Properties Of Solid Monodisperse Aerosols Of ...

    African Journals Online (AJOL)

    A monodisperse aerosol generator (MAGE) was used to generate calibration or monodisperse aerosols containing stearic acid and carnauba wax. Some of the factors affecting the size of aerosol particles generated with the MAGE were determined. The factors include: temperature of operation of the MAGE, type and purity ...

  20. Monodisperse selenium-substituted hydroxyapatite: Controllable synthesis and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jianpeng [School of Civil Engineering, Xi' an University of Architecture and Technology, Shaanxi 710055 (China); Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Zheng, Xiaoyan; Li, Hui; Fan, Daidi [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Song, Zhanping [School of Civil Engineering, Xi' an University of Architecture and Technology, Shaanxi 710055 (China); Ma, Haixia [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China); Hua, Xiufu, E-mail: hua_xiufu@163.com [Department of Scientific Research and Development, Tsinghua University, Beijing 100084 (China); Hui, Junfeng, E-mail: huijunfeng@126.com [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an, 710069 (China)

    2017-04-01

    Hydroxyapatite (HA) is the major inorganic component of natural bone tissue. As an essential trace element, selenium involves in antioxidation and anticancer of human body. So far, ion-doped hydroxyapatites (HAs) are widely investigated owing to their great applications in field of biomaterial, biological labeling. In this paper, series of monodisperse HA doped with SeO{sub 3}{sup 2−} (SeHA) was successfully synthesized based on the liquid–solid–solution (LSS) strategy. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive spectrometer (EDS). The results indicated that the SeO{sub 3}{sup 2−} doping level of the Se/(P + Se) molar ratio of 0– 0.4 can be requisitely controlled, and the morphology of SeHA nanoparticles varied from nanorods to nanoneedles with increasing Se/(P + Se) molar ratio. Significantly, the as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells, showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone. - Highlights: • Series of SeO{sub 3}{sup 2−} doped HA nanorods or/and nanoneedles were successfully synthesized. • The morphology of the HA nanocrystals can be easily controlled by changing the Se/(P + Se) molar ratio. • The as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells. • Showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone.

  1. Monodisperse selenium-substituted hydroxyapatite: Controllable synthesis and biocompatibility

    International Nuclear Information System (INIS)

    Sun, Jianpeng; Zheng, Xiaoyan; Li, Hui; Fan, Daidi; Song, Zhanping; Ma, Haixia; Hua, Xiufu; Hui, Junfeng

    2017-01-01

    Hydroxyapatite (HA) is the major inorganic component of natural bone tissue. As an essential trace element, selenium involves in antioxidation and anticancer of human body. So far, ion-doped hydroxyapatites (HAs) are widely investigated owing to their great applications in field of biomaterial, biological labeling. In this paper, series of monodisperse HA doped with SeO 3 2− (SeHA) was successfully synthesized based on the liquid–solid–solution (LSS) strategy. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive spectrometer (EDS). The results indicated that the SeO 3 2− doping level of the Se/(P + Se) molar ratio of 0– 0.4 can be requisitely controlled, and the morphology of SeHA nanoparticles varied from nanorods to nanoneedles with increasing Se/(P + Se) molar ratio. Significantly, the as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells, showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone. - Highlights: • Series of SeO 3 2− doped HA nanorods or/and nanoneedles were successfully synthesized. • The morphology of the HA nanocrystals can be easily controlled by changing the Se/(P + Se) molar ratio. • The as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells. • Showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone

  2. Logarithmic Exchange Kinetics in Monodisperse Copolymeric Micelles

    Science.gov (United States)

    García Daza, Fabián A.; Bonet Avalos, Josep; Mackie, Allan D.

    2017-06-01

    Experimental measurements of the relaxation kinetics of copolymeric surfactant exchange for micellar systems unexpectedly show a peculiar logarithmic decay. Several authors use polydispersity as an explanation for this behavior. However, in coarse-grained simulations that preserve microscopic details of the surfactants, we find evidence of the same logarithmic behavior. Since we use a strictly monodisperse distribution of chain lengths such a relaxation process cannot be attributed to polydispersity, but has to be caused by an inherent physical process characteristic of this type of system. This is supported by the fact that the decay is specifically logarithmic and not a power law with an exponent inherited from the particular polydispersity distribution of the sample. We suggest that the degeneracy of the energy states of the hydrophobic block in the core, which is broken on leaving the micelle, can qualitatively explain the broad distribution of energy barriers, which gives rise to the observed nonexponential relaxation.

  3. Synthesis and characterization of monodispersed silver nanoparticles

    Science.gov (United States)

    Jegatha Christy, A.; Umadevi, M.

    2012-09-01

    Synthesis of silver nanoparticles (NPs) has become a fascinating and important field of applied chemical research. In this paper silver NPs were prepared using silver nitrate (AgNO3), gelatin, and cetyl trimethyl ammonium bromide (CTAB). The prepared silver NPs were exposed under the laser ablation. In our photochemical procedure, gelatin acts as a biopolymer and CTAB acts as a reducing agent. The appearance of surface plasmon band around 410 nm indicates the formation of silver NPs. The nature of the prepared silver NPs in the face-centered cubic (fcc) structure are confirmed by the peaks in the x-ray diffraction (XRD) pattern corresponding to (111), (200), (220) and (311) planes. Monodispersed, stable, spherical silver NPs with diameter about 10 nm were obtained and confirmed by high-resolution transmission electron microscope (HRTEM).

  4. Synthesis and characterization of monodispersed silver nanoparticles

    International Nuclear Information System (INIS)

    Christy, A Jegatha; Umadevi, M

    2012-01-01

    Synthesis of silver nanoparticles (NPs) has become a fascinating and important field of applied chemical research. In this paper silver NPs were prepared using silver nitrate (AgNO 3 ), gelatin, and cetyl trimethyl ammonium bromide (CTAB). The prepared silver NPs were exposed under the laser ablation. In our photochemical procedure, gelatin acts as a biopolymer and CTAB acts as a reducing agent. The appearance of surface plasmon band around 410 nm indicates the formation of silver NPs. The nature of the prepared silver NPs in the face-centered cubic (fcc) structure are confirmed by the peaks in the x-ray diffraction (XRD) pattern corresponding to (111), (200), (220) and (311) planes. Monodispersed, stable, spherical silver NPs with diameter about 10 nm were obtained and confirmed by high-resolution transmission electron microscope (HRTEM). (paper)

  5. Characterization of a monodispersed aerosol exposure system for beagle dogs

    International Nuclear Information System (INIS)

    Cannon, W.C.; Herring, J.P.; Craig, D.K.

    1978-01-01

    A monodispersed aerosol exposure system for dogs is described and data are presented on aerosol depositions in the exposure system which could affect the aerosol presented to the animals by reducing the concentration and changing the particle size distribution

  6. A general approach for monodisperse colloidal perovskites, Chemistry of Materials

    NARCIS (Netherlands)

    Demirors, A.F.; Imhof, A.

    2009-01-01

    We describe a novel general method for synthesizing monodisperse colloidal perovskite particles at room temperature by postsynthesis addition of metal hydroxides to amorphous titania colloids. In previous work, we used titania particles to synthesize homogenously mixed silica-titania composite

  7. Growth of monodisperse mesoscopic metal-oxide colloids under constant monomer supply

    Science.gov (United States)

    Nozawa, Koh; Delville, Marie-Hélène; Ushiki, Hideharu; Panizza, Pascal; Delville, Jean-Pierre

    2005-07-01

    In closed systems, control over the size of monodisperse metal-oxide colloids is generally limited to submicrometric dimensions. To overcome this difficulty, we explore the formation and growth of silica particles under constant monomer supply. The monomer source is externally driven by the progressive addition into the system of one of the precursors. Monodisperse spherical particles are produced up to a mesoscopic size. We analyze their growth versus the monomer addition rate at different temperatures. Our results show that in the presence of a continuous monomer addition, growth is limited by diffusion over the investigated temporal window. Using the temperature variation of the growth rate, we prove that rescaling leads to a data reduction onto a single master curve. Contrary to the growth process, the final particle’s size reached after the end of the reagent supply strongly depends on the addition rate. The variation of the final particle size versus addition rate can be deduced from an analogy with crystal formation in jet precipitation. Within this framework, and using the temperature dependences of both the particle growth law and the final size, we determine the value of the molecular heat of dissolution associated to the silica solubility. These observations support the fact that classical theories of phase-ordering dynamics can be extended to the synthesis of inorganic particles. The emergence of a master behavior in the presence of continuous monomer addition also suggests the extension of these theories to open systems.

  8. Microwave Synthesized Monodisperse CdS Spheres of Different Size and Color for Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Carlos A. Rodríguez-Castañeda

    2015-01-01

    Full Text Available Monodisperse CdS spheres of size of 40 to 140 nm were obtained by microwave heating from basic solutions. It is observed that larger CdS spheres were formed at lower solution pH (8.4–8.8 and smaller ones at higher solution pH (10.8–11.3. The color of CdS products changed with solution pH and reaction temperature; those synthesized at lower pH and temperature were of green-yellow color, whereas those formed at higher pH and temperature were of orange-yellow color. A good photovoltage was observed in CdS:poly(3-hexylthiophene solar cells with spherical CdS particles. This is due to the good dispersion of CdS nanoparticles in P3HT solution that led to a large interface area between the organic and inorganic semiconductors. Higher photocurrent density was obtained in green-yellow CdS particles of lower defect density. The efficient microwave chemistry accelerated the hydrolysis of thiourea in pH lower than 9 and produced monodisperse spherical CdS nanoparticles suitable for solar cell applications.

  9. A Convenient and Templated Method for the Fabrication of Monodisperse Micrometer Hollow Titania Spheres

    Directory of Open Access Journals (Sweden)

    Haibo Yao

    2013-01-01

    Full Text Available A simple and widely applicable methodology was presented to synthesize monodisperse micrometer hollow titania spheres (HTS based on the templating method. It was performed by using the preformed poly(styrene-acrylic acid (PSA as template spheres which was mixed with tetrabutyltitanate (TBOT in an ethanol solvent under steam treatment. The HTS which were obtained by the calcination of PSA/TiO2 composite core-shell spheres had a narrow particle size distribution and commendable surface topography characterized by SEM. The calcined HTS at 500°C displayed crystalline reflection peaks that were characteristic to the anatase phase by XRD. Moreover, some key influencing factors including TBOT concentration and reaction time were analyzed. As expected, the diameter of HTS could be readily controlled by altering the size of PSA template spheres. In addition, the approach was also applied to fabricate hollow zirconia spheres and other inorganic spheres.

  10. Dynamics at the nanoscale

    International Nuclear Information System (INIS)

    Stoneham, A.M.; Gavartin, J.L.

    2007-01-01

    However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

  11. Enabling complex nanoscale pattern customization using directed self-assembly.

    Science.gov (United States)

    Doerk, Gregory S; Cheng, Joy Y; Singh, Gurpreet; Rettner, Charles T; Pitera, Jed W; Balakrishnan, Srinivasan; Arellano, Noel; Sanders, Daniel P

    2014-12-16

    Block copolymer directed self-assembly is an attractive method to fabricate highly uniform nanoscale features for various technological applications, but the dense periodicity of block copolymer features limits the complexity of the resulting patterns and their potential utility. Therefore, customizability of nanoscale patterns has been a long-standing goal for using directed self-assembly in device fabrication. Here we show that a hybrid organic/inorganic chemical pattern serves as a guiding pattern for self-assembly as well as a self-aligned mask for pattern customization through cotransfer of aligned block copolymer features and an inorganic prepattern. As informed by a phenomenological model, deliberate process engineering is implemented to maintain global alignment of block copolymer features over arbitrarily shaped, 'masking' features incorporated into the chemical patterns. These hybrid chemical patterns with embedded customization information enable deterministic, complex two-dimensional nanoscale pattern customization through directed self-assembly.

  12. Programmed assembly of nanoscale structures using peptoids.

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jianhua (University of the Pacific, Stockton, CA); Russell, Scott (California State University, Stanislaus, Turlock, CA); Morishetti, Kiran (University of the Pacific, Stockton, CA); Robinson, David B.; Zuckermann, Ronald N. (Lawrence Berkeley National Laboratory, Berkeley, CA); Buffleben, George M.; Hjelm, Rex P. (Los Alamos National Laboratory, Los Alamos, NM); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM)

    2011-02-01

    Sequence-specific polymers are the basis of the most promising approaches to bottom-up programmed assembly of nanoscale materials. Examples include artificial peptides and nucleic acids. Another class is oligo(N-functional glycine)s, also known as peptoids, which permit greater sidegroup diversity and conformational control, and can be easier to synthesize and purify. We have developed a set of peptoids that can be used to make inorganic nanoparticles more compatible with biological sequence-specific polymers so that they can be incorporated into nucleic acid or other biologically based nanostructures. Peptoids offer degrees of modularity, versatility, and predictability that equal or exceed other sequence-specific polymers, allowing for rational design of oligomers for a specific purpose. This degree of control will be essential to the development of arbitrarily designed nanoscale structures.

  13. Optical properties of monodispersive FePt nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [Center for Sustainable Environmental Technologies, Iowa State University, Ames, IA 50011 (United States)

    2004-10-01

    The optical properties of monodispersive FePt nanoparticle films were investigated using spectroscopic ellipsometry in the energy range of 1.5 to 5.5 eV. The monodispersive FePt nanoparticle film was stabilized on a Si substrate by means of an organosilane coupling film, resulting in the formation of a (Si/SiO{sub 2}/APTS/FePt nanoparticles monolayer) structure. Multilayer optical models were employed to study the contribution of the FePt nanoparticles to the measured optical properties of the monodispersive FePt nanoparticle film, and to estimate the optical properties of the FePt nanoparticle layer. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Synthetic routes to a nanoscale inorganic cluster [Ga{sub 13}(μ{sub 3}-OH){sub 6}(μ{sub 2}-OH){sub 18}(H{sub 2}O)](NO{sub 3}){sub 15} evaluated by solid-state {sup 71}Ga NMR

    Energy Technology Data Exchange (ETDEWEB)

    Hammann, Blake A. [Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130 (United States); Marsh, David A. [Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403 (United States); Ma, Zayd L. [Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130 (United States); Wood, Suzannah R. [Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403 (United States); Eric West, Michael [Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130 (United States); Johnson, Darren W. [Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403 (United States); Hayes, Sophia E., E-mail: hayes@wustl.edu [Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130 (United States)

    2016-10-15

    Solid-state {sup 71}Ga NMR was used to characterize a series of [Ga{sub 13}(μ{sub 3}-OH){sub 6}(μ{sub 2}-OH){sub 18}(H{sub 2}O)](NO{sub 3}){sub 15} “Ga{sub 13}” molecular clusters synthesized by multiple methods. These molecular clusters are precursors to thin film electronics and may be employed in energy applications. The synthetic routes provide varying levels of impurities in the solid phase, and these impurities often elude traditional characterization techniques such as powder X-ray diffraction and Raman spectroscopy. Solid-state NMR can provide a window into the gallium species even in amorphous phases. This information is vital in order to prevent the impurities from causing defect sites in the corresponding thin films upon gelation and condensation (polymerization) of the Ga{sub 13} clusters. This work demonstrates the resolving power of solid-state NMR to evaluate structure and synthetic quality in the solid state, and the application of high-field NMR to study quadrupolar species, such as {sup 71}Ga. - Graphical abstract: The various synthetic routes and {sup 71}Ga solid-state NMR spectra of the nanoscale inorganic cluster [Ga{sub 13}(μ{sub 3}-OH){sub 6}(μ{sub 2}-OH){sub 18}(H{sub 2}O)](NO{sub 3}){sub 15}. - Highlights: • Solid-state {sup 71}Ga NMR of hydroxo-aquo metal clusters and the impurities present. • High-field NMR capability allows for quadrupolar species, such as {sup 71}Ga, to be routinely studied. • Efficient and environmentally friendly synthetic routes have been developed to prepare hydroxo-aquo metal clusters.

  15. Nanoscale Ionic Liquids

    Science.gov (United States)

    2006-11-01

    Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

  16. Spintronics in nanoscale devices

    CERN Document Server

    Hedin, Eric R

    2013-01-01

    By exploiting the novel properties of quantum dots and nanoscale Aharonov-Bohm rings together with the electronic and magnetic properties of various semiconductor materials and graphene, researchers have conducted numerous theoretical and computational modeling studies and experimental tests that show promising behavior for spintronics applications. Spin polarization and spin-filtering capabilities and the ability to manipulate the electron spin state through external magnetic or electric fields have demonstrated the promise of workable nanoscale devices for computing and memory applications.

  17. Segmented block copolymers with monodisperse aramide end-segments

    NARCIS (Netherlands)

    Araichimani, A.; Gaymans, R.J.

    2008-01-01

    Segmented block copolymers were synthesized using monodisperse diaramide (TT) as hard segments and PTMO with a molecular weight of 2 900 g · mol-1 as soft segments. The aramide: PTMO segment ratio was increased from 1:1 to 2:1 thereby changing the structure from a high molecular weight multi-block

  18. Engineering Platinum Alloy Electrocatalysts in Nanoscale for PEMFC Application

    Energy Technology Data Exchange (ETDEWEB)

    He, Ting [Idaho National Laboratory

    2016-03-01

    Fuel cells are expected to be a key next-generation energy source used for vehicles and homes, offering high energy conversion efficiency and minimal pollutant emissions. However, due to large overpotentials on anode and cathode, the efficiency is still much lower than theoretically predicted. During the past decades, considerable efforts have been made to investigate synergy effect of platinum alloyed with base metals. But, engineering the alloy particles in nanoscale has been a challenge. Most important challenges in developing nanostructured materials are the abilities to control size, monodispersity, microcomposition, and even morphology or self-assembly capability, so called Nanomaterials-by-Design, which requires interdisciplinary collaborations among computational modeling, chemical synthesis, nanoscale characterization as well as manufacturing processing. Electrocatalysts, particularly fuel cell catalysts, are dramatically different from heterogeneous catalysts because the surface area in micropores cannot be electrochemically controlled on the same time scale as more transport accessible surfaces. Therefore, electrocatalytic architectures need minimal microporous surface area while maximizing surfaces accessible through mesopores or macropores, and to "pin" the most active, highest performance physicochemical state of the materials even when exposed to thermodynamic forces, which would otherwise drive restructuring, crystallization, or densification of the nanoscale materials. In this presentation, results of engineering nanoscale platinum alloy particles down to 2 ~ 4 nm will be discussed. Based on nature of alloyed base metals, various synthesis technologies have been studied and developed to achieve capabilities of controlling particle size and particle microcomposition, namely, core-shell synthesis, microemulsion technique, thermal decomposition process, surface organometallic chemical method, etc. The results show that by careful engineering the

  19. Self-assembly of monodisperse starburst carbon spheres into hierarchically organized nanostructured supercapacitor electrodes.

    Science.gov (United States)

    Kim, Sung-Kon; Jung, Euiyeon; Goodman, Matthew D; Schweizer, Kenneth S; Tatsuda, Narihito; Yano, Kazuhisa; Braun, Paul V

    2015-05-06

    We report a three-dimensional (3D) porous carbon electrode containing both nanoscale and microscale porosity, which has been hierarchically organized to provide efficient ion and electron transport. The electrode organization is provided via the colloidal self-assembly of monodisperse starburst carbon spheres (MSCSs). The periodic close-packing of the MSCSs provides continuous pores inside the 3D structure that facilitate ion and electron transport (electrode electrical conductivity ∼0.35 S m(-1)), and the internal meso- and micropores of the MSCS provide a good specific capacitance. The capacitance of the 3D-ordered porous MSCS electrode is ∼58 F g(-1) at 0.58 A g(-1), 48% larger than that of disordered MSCS electrode at the same rate. At 1 A g(-1) the capacitance of the ordered electrode is 57 F g(-1) (95% of the 0.24 A g(-1) value), which is 64% greater than the capacitance of the disordered electrode at the same rate. The ordered electrode preserves 95% of its initial capacitance after 4000 charging/discharging cycles.

  20. A co-flow-focusing monodisperse microbubble generator

    KAUST Repository

    Zhang, Jiaming; Li, Erqiang; Thoroddsen, Sigurdur T

    2014-01-01

    We use a simple and inexpensive microfluidic device, which is based on microscope glass slides and two tapered glass capillaries, to produce monodisperse microbubbles. The innermost capillary used for transporting the gas is inserted into the second capillary, with its 2 μm sharp tip aligned with the center of the converging-diverging throat of the second capillary. This configuration provides a small and smooth gas flow rate, and a high velocity gradient at the tube outlet. Highly monodisperse microbubbles with diameters ranging from 3.5 to 60 microns have been successfully produced at a rate of up to 40 kHz. A simple scaling law, which is based on the capillary number and liquid-to-gas flow rate ratio, successfully predicts the bubble size. © 2014 IOP Publishing Ltd.

  1. A co-flow-focusing monodisperse microbubble generator

    KAUST Repository

    Zhang, Jiaming

    2014-02-14

    We use a simple and inexpensive microfluidic device, which is based on microscope glass slides and two tapered glass capillaries, to produce monodisperse microbubbles. The innermost capillary used for transporting the gas is inserted into the second capillary, with its 2 μm sharp tip aligned with the center of the converging-diverging throat of the second capillary. This configuration provides a small and smooth gas flow rate, and a high velocity gradient at the tube outlet. Highly monodisperse microbubbles with diameters ranging from 3.5 to 60 microns have been successfully produced at a rate of up to 40 kHz. A simple scaling law, which is based on the capillary number and liquid-to-gas flow rate ratio, successfully predicts the bubble size. © 2014 IOP Publishing Ltd.

  2. Synthesis of Monodisperse Iron Oxide Nanoparticles without Surfactants

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Yang

    2014-01-01

    Full Text Available Monodisperse iron oxide nanoparticles could be successfully synthesized with two kinds of precipitants through a precipitation method. As-prepared nanoparticles in the size around 10 nm with regular spherical-like shape were achieved by adjusting pH values. NaOH and NH3·H2O were used as two precipitants for comparison. The average size of nanoparticles with NH3·H2O precipitant got smaller and represented better dispersibility, while nanoparticles with NaOH precipitant represented better magnetic property. This work provided a simple method without using any organic solvents, organic metal salts, or surfactants which could easily obtain monodisperse nanoparticles with tunable morphology.

  3. Nanoscale thermal transport. II. 2003-2012

    Science.gov (United States)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ˜ 1 nm , the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and thermal

  4. Nanoscale thermal transport. II. 2003–2012

    International Nuclear Information System (INIS)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-01-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ∼1 nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and

  5. The self-assembly of monodisperse nanospheres within microtubes

    International Nuclear Information System (INIS)

    Zheng Yuebing; Juluri, Bala Krishna; Huang, Tony Jun

    2007-01-01

    Self-assembled monodisperse nanospheres within microtubes have been fabricated and characterized. In comparison with colloidal crystals formed on planar substrates, colloidal nanocrystals self-assembled in microtubes demonstrate high spatial symmetry in their optical transmission and reflection properties. The dynamic self-assembly process inside microtubes is investigated by combining temporal- and spatial-spectrophotometric measurements. The understanding of this process is achieved through both experimentally recorded reflection spectra and finite difference time domain (FDTD)-based simulation results

  6. Laboratory evaluation of a vibrating orifice monodisperse aerosol generator

    International Nuclear Information System (INIS)

    Everitt, N.M.; Snelling, K.W.

    1985-02-01

    The Berglund-Liu vibrating orifice aerosol generator is capable of producing monodisperse particles in the diameter range 5 to 50 μm. Experiments have been carried out to set up and evaluate such a generator for the preparation of standard liquid (olive oil) and solid (methylene blue) aerosols in the size range 8 to 13 μm. Modifications have been made to the apparatus to improve its performance and increase its particle output. (author)

  7. Hybrid thin films derived from UV-curable acrylate-modified waterborne polyurethane and monodispersed colloidal silica

    Directory of Open Access Journals (Sweden)

    C. H. Yang

    2012-01-01

    Full Text Available Hybrid thin films containing nano-sized inorganic domains were synthesized from UV-curable acrylate-modified waterborne polyurethane (WPU-AC and monodispersed colloidal silica with coupling agent. The coupling agent, 3-(trimethoxysilylpropyl methacrylate (MSMA, was bonded onto colloidal silica first, and then mixed with WPU-AC to form a precursor solution. This precursor was spin coated, dried and UV-cured to generate the hybrid films. The silica content in the hybrid thin films was varied from 0 to 30 wt%. Experimental results showed the aggregation of silica particles in the hybrid films. Thus, the silica domain in the hybrid films was varied from 30 to 50 nm by the different ratios of MSMAsilica to WPU-AC. The prepared hybrid films from the crosslinked WPU-AC/MSMA-silica showed much better thermal stability and mechanical properties than pure WPU-AC.

  8. Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica.

    Science.gov (United States)

    Malgras, Victor; Tominaka, Satoshi; Ryan, James W; Henzie, Joel; Takei, Toshiaki; Ohara, Koji; Yamauchi, Yusuke

    2016-10-13

    Hybrid organic-inorganic metal halide perovskites have fascinating electronic properties and have already been implemented in various devices. Although the behavior of bulk metal halide perovskites has been widely studied, the properties of perovskite nanocrystals are less well-understood because synthesizing them is still very challenging, in part because of stability. Here we demonstrate a simple and versatile method to grow monodisperse CH 3 NH 3 PbBr x I x-3 perovskite nanocrystals inside mesoporous silica templates. The size of the nanocrystal is governed by the pore size of the templates (3.3, 3.7, 4.2, 6.2, and 7.1 nm). In-depth structural analysis shows that the nanocrystals maintain the perovskite crystal structure, but it is slightly distorted. Quantum confinement was observed by tuning the size of the particles via the template. This approach provides an additional route to tune the optical bandgap of the nanocrystal. The level of quantum confinement was modeled taking into account the dimensions of the rod-shaped nanocrystals and their close packing inside the channels of the template. Photoluminescence measurements on CH 3 NH 3 PbBr clearly show a shift from green to blue as the pore size is decreased. Synthesizing perovskite nanostructures in templates improves their stability and enables tunable electronic properties via quantum confinement. These structures may be useful as reference materials for comparison with other perovskites, or as functional materials in all solid-state light-emitting diodes.

  9. Synthesis and characterization of titania-based monodisperse fluorescent europium nanoparticles for biolabeling

    International Nuclear Information System (INIS)

    Tan Mingqian; Wang Guilan; Ye Zhiqiang; Yuan Jingli

    2006-01-01

    Inorganic-organic hybrid titania-based nanoparticles covalently bound to a fluorescent Eu 3+ chelate of 4,4'-bis(1'',1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl) chlorosulfo-o-terphenyl (BHHCT-Eu 3+ ) were synthesized by a sol-gel technique. A conjugate of BHHCT with 3-[2-(2-aminoethylamino) ethylamino]propyl-trimethoxysilane (APTS) was used as a precursor for the nanoparticle preparation and monodisperse nanoparticles consisting of titania network and silica sub-network covalently bound to the Eu 3+ chelate were prepared by the copolymerization of APTS-BHHCT conjugate, titanium tetraisopropoxide (TTIP) and free APTS in EuCl 3 water-alcohol solution. The effects of reaction conditions on size and fluorescence lifetime of the nanoparticles were investigated. The characterizations by transmission electron microscopy and fluorometric methods indicate that the nanoparticles are near spherical and strongly fluorescent having a fluorescence quantum yield of 11.6% and a long fluorescence lifetime of ∼0.4 ms. The direct-introduced amino groups on the nanoparticle's surface by using free APTS in nanoparticle preparation facilitated the biolabeling process of the nanoparticles. The nanoparticle-labeled streptavidin (SA) was prepared and used in a sandwich-type time-resolved fluoroimmunoassay (TR-FIA) of human prostate-specific antigen (PSA) by using a 96-well microtiter plate as the solid phase carrier. The method gives a detection limit of 66 pg/ml for the PSA assay

  10. Ellipsometry at the nanoscale

    CERN Document Server

    Hingerl, Kurt

    2013-01-01

    This book presents and introduces ellipsometry in nanoscience and nanotechnology making a bridge between the classical and nanoscale optical behaviour of materials. It delineates the role of the non-destructive and non-invasive optical diagnostics of ellipsometry in improving science and technology of nanomaterials and related processes by illustrating its exploitation, ranging from fundamental studies of the physics and chemistry of nanostructures to the ultimate goal of turnkey manufacturing control. This book is written for a broad readership: materials scientists, researchers, engineers, as well as students and nanotechnology operators who want to deepen their knowledge about both basics and applications of ellipsometry to nanoscale phenomena. It starts as a general introduction for people curious to enter the fields of ellipsometry and polarimetry applied to nanomaterials and progresses to articles by experts on specific fields that span from plasmonics, optics, to semiconductors and flexible electronics...

  11. Morphologically and size uniform monodisperse particles and their shape-directed self-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Joshua E.; Bell, Howard Y.; Ye, Xingchen; Murray, Christopher Bruce

    2017-09-12

    Monodisperse particles having: a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology are disclosed. Due to their uniform size and shape, the monodisperse particles self assemble into superlattices. The particles may be luminescent particles such as down-converting phosphor particles and up-converting phosphors. The monodisperse particles of the invention have a rare earth-containing lattice which in one embodiment may be an yttrium-containing lattice or in another may be a lanthanide-containing lattice. The monodisperse particles may have different optical properties based on their composition, their size, and/or their morphology (or shape). Also disclosed is a combination of at least two types of monodisperse particles, where each type is a plurality of monodisperse particles having a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology; and where the types of monodisperse particles differ from one another by composition, by size, or by morphology. In a preferred embodiment, the types of monodisperse particles have the same composition but different morphologies. Methods of making and methods of using the monodisperse particles are disclosed.

  12. Nanoscale thermal transport

    Science.gov (United States)

    Cahill, David G.; Ford, Wayne K.; Goodson, Kenneth E.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Merlin, Roberto; Phillpot, Simon R.

    2003-01-01

    Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid-solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The

  13. Atomically Monodisperse Nickel Nanoclusters as Highly Active Electrocatalysts for Water Oxidation

    KAUST Repository

    Joya, Khurram

    2016-04-08

    Achieving water splitting at low overpotential with high oxygen evolution efficiency and stability is important for realizing solar to chemical energy conversion devices. Herein we report the synthesis, characterization and electrochemical evaluation of highly active nickel nanoclusters (Ni NCs) for water oxidation at low overpotential. These atomically precise and monodisperse Ni NCs are characterized by using UV-visible absorption spectroscopy, single crystal X-ray diffraction and mass spectrometry. The molecular formulae of these Ni NCs are found to be Ni4(PET)8 and Ni6(PET)12 and are highly active electrocatalysts for oxygen evolution without any pre-conditioning. Ni4(PET)8 are slightly better catalysts than Ni6(PET)12 and initiate the oxygen evolution at an amazingly low overpotential of ~1.51 V (vs RHE; η ≈ 280 mV). The peak oxygen evolution current density (J) of ~150 mA cm–2 at 2.0 V (vs. RHE) with a Tafel slope of 38 mV dec–1 is observed using Ni4(PET)8. These results are comparable to the state-of-the art RuO2 electrocatalyst, which is highly expensive and rare compared to Ni-based materials. Sustained oxygen generation for several hours with an applied current density of 20 mA cm–2 demonstrates the long-term stability and activity of these Ni NCs towards electrocatalytic water oxidation. This unique approach provides a facile method to prepare cost-effective, nanoscale and highly efficient electrocatalysts for water oxidation.

  14. Elongational viscosity of monodisperse and bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    The startup and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 kg/mole (PS52K) and 103 kg/mole (PS103K), and for three bidisperse polystyrene melts. The bidisperse melts consist of PS103K or PS52K and a monodisperse...... (closed loop proportional regulator) using the laser in such a way that the stretch rate at the neck is kept constant. The rheometer has been described in more detail in (A. Bach, H.K. Rasmussen and O. Hassager, Journal of Rheology, 47 (2003) 429). PS390K show a decrease in the steady viscosity as a power......-law function of the elongational rate (A. Bach, K. Almdal, H.K. Rasmussen and O. Hassager, Macromolecules 36 (2003) 5174). PS52K and PS103K show that the steady viscosity has a maximum that is respectively 100% and 50% above 3 times the zero-shear-rate viscosity. The bidisperse melts show a significant...

  15. Rocket Science at the Nanoscale.

    Science.gov (United States)

    Li, Jinxing; Rozen, Isaac; Wang, Joseph

    2016-06-28

    Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way for designing multifunctional and intelligent nanoscale machines. These multipurpose nanoscale shuttles can propel and function in complex real-life media, actively transporting and releasing therapeutic payloads and remediation agents for diverse biomedical and environmental applications. This review discusses the challenges of designing efficient MNRs and presents an overview of their propulsion behavior, fabrication methods, potential rocket fuels, navigation strategies, practical applications, and the future prospects of rocket science and technology at the nanoscale.

  16. Symposium GC: Nanoscale Charge Transport in Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bommisetty, Venkat [Univ. of South Dakota, Vermillion, SD (United States)

    2011-06-23

    This paper provides a summary only and table of contents of the sessions. Excitonic solar cells, including all-organic, hybrid organic-inorganic and dye-sensitized solar cells (DSSCs), offer strong potential for inexpensive and large-area solar energy conversion. Unlike traditional inorganic semiconductor solar cells, where all the charge generation and collection processes are well understood, these excitonic solar cells contain extremely disordered structures with complex interfaces which results in large variations in nanoscale electronic properties and has a strong influence on carrier generation, transport, dissociation and collection. Detailed understanding of these processes is important for fabrication of highly efficient solar cells. Efforts to improve efficiency are underway at a large number of research groups throughout the world focused on inorganic and organic semiconductors, photonics, photophysics, charge transport, nanoscience, ultrafast spectroscopy, photonics, semiconductor processing, device physics, device structures, interface structure etc. Rapid progress in this multidisciplinary area requires strong synergetic efforts among researchers from diverse backgrounds. Such effort can lead to novel methods for development of new materials with improved photon harvesting and interfacial treatments for improved carrier transport, process optimization to yield ordered nanoscale morphologies with well defined electronic structures.

  17. Nanostructural and magnetic studies of virtually monodispersed NiFe2O4 nanocrystals synthesized by a liquid–solid-solution assisted hydrothermal route

    International Nuclear Information System (INIS)

    Li Xinghua; Tan Guoguo; Chen Wei; Zhou Baofan; Xue Desheng; Peng Yong; Li, Fashen; Mellors, Nigel J.

    2012-01-01

    This study presents a comprehensively and systematically structural, chemical and magnetic characterization of ∼9.5 nm virtually monodispersed nickel ferrite (NiFe 2 O 4 ) nanoparticles prepared using a modified liquid–solid-solution (LSS) assisted hydrothermal method. Lattice-resolution scanning transmission electron microscope (STEM) and converged beam electron diffraction pattern (CBED) techniques are adapted to characterize the detailed spatial morphology and crystal structure of individual NiFe 2 O 4 particles at nano scale for the first time. It is found that each NiFe 2 O 4 nanoparticle is single crystal with an fcc structure. The morphology investigation reveals that the prepared NiFe 2 O 4 nanoparticles of which the surfaces are decorated by oleic acid are dispersed individually in hexane. The chemical composition of nickel ferrite nanoparticles is measured to be 1:2 atomic ratio of Ni:Fe, indicating a pure NiFe 2 O 4 composition. Magnetic measurements reveal that the as-synthesized nanocrystals displayed superparamagnetic behavior at room temperature and were ferromagnetic at 10 K. The nanoscale characterization and magnetic investigation of monodispersed NiFe 2 O 4 nanoparticles should be significant for its potential applications in the field of biomedicine and magnetic fluid using them as magnetic materials.

  18. Flow and Failure in Extension of Monodisperse Polymer Melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.

    is commonly referred to be of either brittle (e.g. cohesive type) or of liquid (e.g. necking type) nature. Here the focus will be on monodisperse polymers, to study numerically the sample flow dynamics in dual wind-up extensional rheometers. The computations are within the ideas of the microstructural......It is well known that failure or rupture phenomenon appears in the extension of polymer melts. These appear not only as failure in extension rheometers, but also as sharkskin, developments of holes in thin polymeric films etc. Sometime these ruptures appear spontaneous as well. The rupture...... 'interchain pressure' theory based on the molecular stress function constitutive model for the polymer melt flow. The purpose is twofold. Primarily to present to what extend the experimentally observed failure, appearing during or after (e.g. as a spontaneous failure) extension, can be explained within...

  19. Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

    International Nuclear Information System (INIS)

    Seto, Takafumi; Koga, Kenji; Akinaga, Hiroyuki; Takano, Fumiyoshi; Orii, Takaaki; Hirasawa, Makoto

    2006-01-01

    Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co-Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism

  20. Monodisperse Silver Nanoparticles Synthesized by a Microwave-Assisted Method

    International Nuclear Information System (INIS)

    Shao-Peng, Zhu; Shao-Chun, Tang; Xiang-Kang, Meng

    2009-01-01

    Silver nanoparticles with an average size of about 20 nm are synthesized in a colloidal solution with the aid of microwave irradiation. Neither additional reductant nor stabilizer is required in this microwave-assisted method. The color of the colloidal solution is found to be dark green, different from the characteristic yellow of silver colloidal solutions. The silver nanoparticles in the colloidal solution have a narrow size distribution and large yield quantity. UV-visible absorption spectroscopy analysis reveals that the as-synthesized monodisperse silver nanoparticles have exceptional optical properties. Raman spectroscopy measurements demonstrate that these silver nanoparticles exhibit a notable surface-enhanced Raman scattering ability. (cross-disciplinary physics and related areas of science and technology)

  1. Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Seto, Takafumi, E-mail: t.seto@aist.go.jp; Koga, Kenji; Akinaga, Hiroyuki; Takano, Fumiyoshi; Orii, Takaaki; Hirasawa, Makoto [National Institute of Advanced Industrial Science and Technology (AIST), Research Consortium for Synthetic Nano-Function Materials Project (SYNAF) (Japan)

    2006-08-15

    Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co-Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism.

  2. Template synthesis of highly crystalline and monodisperse iron oxide pigments of nanosize

    International Nuclear Information System (INIS)

    Sreeram, Kalarical Janardhanan; Indumathy, Ramasamy; Rajaram, Ananthanarayanan; Nair, Balachandran Unni; Ramasami, Thirumalachari

    2006-01-01

    Synthesis of highly crystalline and monodisperse iron oxide nanoparticles is reported. The separation of Fe centers through site-specific binding to a polysaccharide-alginate matrix enables the generation of particles with a monodisperse or narrow size distribution character, resulting in transparent pigments. Site-specific interactions coupled with gel like character of alginate is proposed as the mechanism behind generation of lower particle sizes. Alginate-Fe complexes developed were subjected to heat treatment to provide for crystalline character and development of hematite (α-Fe 2 O 3 ). Conditions most ideal for achieving monodispersity and lower sizes have been optimized and confirmed through microscopic and photon correlation spectroscopic measurements

  3. Nanoscale effects in interdiffusion

    International Nuclear Information System (INIS)

    Erdelyi, Z.; Langer, G.A.; Beke, D.L.; Csik, A.

    2007-01-01

    Complete text of publication follows. Diffusion on the nano/atomic scales in multilayers, thin films has many challenging features even if the role of structural defects can be neglected and 'only' the effects related to the nano/atomic scale raise. The most basic equations to describe the diffusion are Fick's equations. It is important to emphasize that the diffusion coefficient in Fick's equations is in general composition independent and Fick's classical equations do not include the stress effects, which can have important influence onto the diffusion especially on the nano/atomic scale. We illustrate that the continuum descriptions of the diffusion cannot be applied automatically on such short distances, the classical continuum approximations (Fick's laws) cannot describe correctly the atomic movements. They predict faster kinetics than the atomistic models and the interface shift is always proportional to the square root of the time. However, the kinetics can be even linear on the nano/atomic scale. We have shown from computer simulations that Fick's laws violate on the nanoscale either in completely or restricted miscible systems. This is strongly related to the discrete character of the system on the nanoscale and to the highly neglected fact in the literature that the diffusion coefficients depend on the composition. As will be seen the composition dependence of D is very important and has very significant influence on the diffusion kinetics on the nano/atomic scales. It originates from the fact that usually the diffusion coefficients are different in an A and in a B matrix. Consequently in case of a real interface, which is not atomically sharp, i.e. there is a more or less intermixed region between the pure A and B matrixes, the diffusion coefficient changes continuously while e.g. an A atom diffuses from the pure A matrix into the pure B. This feature can be also called diffusion asymmetry. We have also illustrated that in this case not only the

  4. Nanoscale technology in biological systems

    CERN Document Server

    Greco, Ralph S; Smith, R Lane

    2004-01-01

    Reviewing recent accomplishments in the field of nanobiology Nanoscale Technology in Biological Systems introduces the application of nanoscale matrices to human biology. It focuses on the applications of nanotechnology fabrication to biomedical devices and discusses new physical methods for cell isolation and manipulation and intracellular communication at the molecular level. It also explores the application of nanobiology to cardiovascular diseases, oncology, transplantation, and a range of related disciplines. This book build a strong background in nanotechnology and nanobiology ideal for

  5. Friction laws at the nanoscale.

    Science.gov (United States)

    Mo, Yifei; Turner, Kevin T; Szlufarska, Izabela

    2009-02-26

    Macroscopic laws of friction do not generally apply to nanoscale contacts. Although continuum mechanics models have been predicted to break down at the nanoscale, they continue to be applied for lack of a better theory. An understanding of how friction force depends on applied load and contact area at these scales is essential for the design of miniaturized devices with optimal mechanical performance. Here we use large-scale molecular dynamics simulations with realistic force fields to establish friction laws in dry nanoscale contacts. We show that friction force depends linearly on the number of atoms that chemically interact across the contact. By defining the contact area as being proportional to this number of interacting atoms, we show that the macroscopically observed linear relationship between friction force and contact area can be extended to the nanoscale. Our model predicts that as the adhesion between the contacting surfaces is reduced, a transition takes place from nonlinear to linear dependence of friction force on load. This transition is consistent with the results of several nanoscale friction experiments. We demonstrate that the breakdown of continuum mechanics can be understood as a result of the rough (multi-asperity) nature of the contact, and show that roughness theories of friction can be applied at the nanoscale.

  6. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert; Herrera, Rafael; Archer, Lynden A.; Giannelis, Emmanuel P.

    2008-01-01

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  7. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  8. Monodispersed Zinc Oxide Nanoparticle-Dye Dyads and Triads

    Energy Technology Data Exchange (ETDEWEB)

    Gladfelter, Wayne L. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry; Blank, David A. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry; Mann, Kent R. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry

    2017-06-22

    events at a fundamental level. This was combined with the synthesis of a broad range of sensitizers that provide systematic variation of the energetics, excited state dynamics, structure and interfacial bonding. The key is that the monodisperse nature and high dispersibility of the ZnO NCs made these experiments reproducible; in essence, the measurements were on discrete molecular species rather than on the complicated mixtures that resulted from the typical fabrication of functional photovoltaic cells. The monodispersed nature of the NCs also allowed the use of quantum confinement to investigate the role of donor/acceptor energetic alignment in chemically identical systems. The results added significantly to our basic understanding of energy and charge transfer events at molecule-semiconductor interfaces and will help the R&D community realize zinc oxide's full potential in solar cell applications.

  9. Mechanical Designs for Inorganic Stretchable Circuits in Soft Electronics.

    Science.gov (United States)

    Wang, Shuodao; Huang, Yonggang; Rogers, John A

    2015-09-01

    Mechanical concepts and designs in inorganic circuits for different levels of stretchability are reviewed in this paper, through discussions of the underlying mechanics and material theories, fabrication procedures for the constituent microscale/nanoscale devices, and experimental characterization. All of the designs reported here adopt heterogeneous structures of rigid and brittle inorganic materials on soft and elastic elastomeric substrates, with mechanical design layouts that isolate large deformations to the elastomer, thereby avoiding potentially destructive plastic strains in the brittle materials. The overall stiffnesses of the electronics, their stretchability, and curvilinear shapes can be designed to match the mechanical properties of biological tissues. The result is a class of soft stretchable electronic systems that are compatible with traditional high-performance inorganic semiconductor technologies. These systems afford promising options for applications in portable biomedical and health-monitoring devices. Mechanics theories and modeling play a key role in understanding the underlining physics and optimization of these systems.

  10. Nanoscale waveguiding methods

    Directory of Open Access Journals (Sweden)

    Wang Chia-Jean

    2007-01-01

    Full Text Available AbstractWhile 32 nm lithography technology is on the horizon for integrated circuit (IC fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.

  11. Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

    KAUST Repository

    Li, Erqiang; Zhang, Jiaming; Thoroddsen, Sigurdur T

    2013-01-01

    of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions

  12. Application of monodisperse fibers and discs to evaluation of the aerodynamic particle sizer

    International Nuclear Information System (INIS)

    Hoover, M.D.; Lipowicz, P.J.; Hanson, R.W.; Yeh, H.C.; Casalnuovo, S.A.

    1988-01-01

    Monodisperse fibers, μm in width and lengths of 5, 10, 20, and 40 μm, as well as monodisperse discs, 2 4 8, or 12 μm in diameter, were prepared using an integrated circuit microchip fabrication technique. Particles were silicon dioxide with thickness of 1 μm. Examination of the particles using a scanning electron microscope showed that they were uniform in shape, with well-defined edges. The particles were suspended in distilled water and aerosolized with a Lovelace nebullizer. The monodisperse particles were used to evaluate the TSI Aerodynamic Particle Sizer (APS). Carbon fibers that were monodisperse in diameter (count median diameter 3.42 μm, geometric standard deviation 1.06) and polydisperse in length (count median length = 28 μm, geometric standard deviation 2.2) were also used. The APS was found to be insensitive to fiber length and only weakly sensitive to disc diameter. (author)

  13. Facile and Scalable Synthesis of Monodispersed Spherical Capsules with a Mesoporous Shell

    KAUST Repository

    Qi, Genggeng

    2010-05-11

    Monodispersed HMSs with tunable particle size and shell thickness were successfully synthesized using relatively concentrated polystyrene latex templates and a silica precursor in a weakly basic ethanol/water mixture. The particle size of the capsules can vary from 100 nm to micrometers. These highly engineered monodispersed capsules synthesized by a facile and scalable process may find applications in drug delivery, catalysis, separationm or as biological and chemical microreactors. © 2010 American Chemical Society.

  14. Facile Synthesis of Monodisperse Gold Nanocrystals Using Virola oleifera

    Science.gov (United States)

    Milaneze, Bárbara A.; Oliveira, Jairo P.; Augusto, Ingrid; Keijok, Wanderson J.; Côrrea, Andressa S.; Ferreira, Débora M.; Nunes, Otalíbio C.; Gonçalves, Rita de Cássia R.; Kitagawa, Rodrigo R.; Celante, Vinícius G.; da Silva, André Romero; Pereira, Ana Claudia H.; Endringer, Denise C.; Schuenck, Ricardo P.; Guimarães, Marco C. C.

    2016-10-01

    The development of new routes and strategies for nanotechnology applications that only employ green synthesis has inspired investigators to devise natural systems. Among these systems, the synthesis of gold nanoparticles using plant extracts has been actively developed as an alternative, efficient, cost-effective, and environmentally safe method for producing nanoparticles, and this approach is also suitable for large-scale synthesis. This study reports reproducible and completely natural gold nanocrystals that were synthesized using Virola oleifera extract. V. oleifera resin is rich in epicatechin, ferulic acid, gallic acid, and flavonoids (i.e., quercetin and eriodictyol). These gold nanoparticles play three roles. First, these nanoparticles exhibit remarkable stability based on their zeta potential. Second, these nanoparticles are functionalized with flavonoids, and third, an efficient, economical, and environmentally friendly mechanism can be employed to produce green nanoparticles with organic compounds on the surface. Our model is capable of reducing the resin of V. oleifera, which creates stability and opens a new avenue for biological applications. This method does not require painstaking conditions or hazardous agents and is a rapid, efficient, and green approach for the fabrication of monodisperse gold nanoparticles.

  15. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    International Nuclear Information System (INIS)

    Cao Feng; Li Dongxu

    2010-01-01

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe 3+ , which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  16. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao Feng; Li Dongxu, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

    2010-03-15

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe{sup 3+}, which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  17. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

    2008-09-01

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  18. Layered inorganic solids

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří; Morris, R. E.; Nachtigall, P.; Roth, Wieslaw Jerzy

    2014-01-01

    Roč. 43, č. 27 (2014), s. 10274-10275 ISSN 1477-9226 Institutional support: RVO:61388955 Keywords : layered inorganic solids * physical chemistry * catalysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.197, year: 2014

  19. Inorganic Coatings Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The inorganic Coatings Lab provides expertise to Navy and Joint Service platforms acquisition IPTs to aid in materials and processing choices which balance up-front...

  20. Inorganic and geological materials

    International Nuclear Information System (INIS)

    Dinnin, J.I.

    1975-01-01

    Recently described methods for applied inorganic analysis are reviewed from an interdisciplinary standpoint. Abstracts and periodical literature up to Nov. 1974, are included for consideration. The following areas of interest are covered: general reviews of inorganic analytical techniques; analytical techniques, areas of application, and analysis of individual elements. Selected books, monographs, and review articles on the analytical chemistry of the elements are listed. (416 references.) (U.S.)

  1. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2010-07-27

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  2. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; Meerwall, Ernst von; Vaia, Richard A.; Rodriguez, Robert; Giannelis, Emmanuel P.

    2010-01-01

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  3. Nanoscale hydroxyapatite particles for bone tissue engineering.

    Science.gov (United States)

    Zhou, Hongjian; Lee, Jaebeom

    2011-07-01

    Hydroxyapatite (HAp) exhibits excellent biocompatibility with soft tissues such as skin, muscle and gums, making it an ideal candidate for orthopedic and dental implants or components of implants. Synthetic HAp has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. However, the low mechanical strength of normal HAp ceramics generally restricts its use to low load-bearing applications. Recent advancements in nanoscience and nanotechnology have reignited investigation of nanoscale HAp formation in order to clearly define the small-scale properties of HAp. It has been suggested that nano-HAp may be an ideal biomaterial due to its good biocompatibility and bone integration ability. HAp biomedical material development has benefited significantly from advancements in nanotechnology. This feature article looks afresh at nano-HAp particles, highlighting the importance of size, crystal morphology control, and composites with other inorganic particles for biomedical material development. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Self assembly of organic nanostructures and dielectrophoretic assembly of inorganic nanowires.

    Science.gov (United States)

    Dholakia, Geetha; Kuo, Steven; Allen, E. L.

    2007-03-01

    Self assembly techniques enable the organization of organic molecules into nanostructures. Currently engineering strategies for efficient assembly and routine integration of inorganic nanoscale objects into functional devices is very limited. AC Dielectrophoresis is an efficient technique to manipulate inorganic nanomaterials into higher dimensional structures. We used an alumina template based sol-gel synthesis method for the growth of various metal oxide nanowires with typical diameters of 100-150 nm, ranging in length from 3-10 μm. Here we report the dielectrophoretic assembly of TiO2 nanowires, an important material for photocatalysis and photovoltaics, onto interdigitated devices. Self assembly in organic nanostructures and its dependence on structure and stereochemistry of the molecule and dielectrophoretic field dependence in the assembly of inorganic nanowires will be compared and contrasted. Tunneling spectroscopy and DOS of these nanoscale systems will also be discussed.

  5. Sensing at the nanoscale

    Science.gov (United States)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  6. Nanoscale phase change memory materials.

    Science.gov (United States)

    Caldwell, Marissa A; Jeyasingh, Rakesh Gnana David; Wong, H-S Philip; Milliron, Delia J

    2012-08-07

    Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.

  7. Controlled synthesis and magnetic properties of monodispersed ceria nanoparticles

    Directory of Open Access Journals (Sweden)

    Sumeet Kumar

    2015-02-01

    Full Text Available In the present study, monodispersed CeO2 nanoparticles (NPs of size 8.5 ± 1.0, 11.4 ± 1.0 and 15.4 ± 1.0 nm were synthesized using the sol-gel method. Size-dependent structural, optical and magnetic properties of as-prepared samples were investigated by X-ray diffraction (XRD, field emission scanning electron microscope (FE-SEM, high resolution transmission electron microscopy (HR-TEM, ultra-violet visible (UV-VIS spectroscopy, Raman spectroscopy and vibrating sample magnetometer (VSM measurements. The value of optical band gap is calculated for each particle size. The decrease in the value of optical band gap with increase of particle size may be attributed to the quantum confinement, which causes to produce localized states created by the oxygen vacancies due to the conversion of Ce4+ into Ce3+ at higher calcination temperature. The Raman spectra showed a peak at ∼461 cm-1 for the particle size 8.5 nm, which is attributed to the 1LO phonon mode. The shift in the Raman peak could be due to lattice strain developed due to variation in particle size. Weak ferromagnetism at room temperature is observed for each particle size. The values of saturation magnetization (Ms, coercivity (Hc and retentivity (Mr are increased with increase of particle size. The increase of Ms and Mr for larger particle size may be explained by increase of density of oxygen vacancies at higher calcination temperature. The latter causes high concentrations of Ce3+ ions activate more coupling between the individual magnetic moments of the Ce ions, leading to an increase of Ms value with the particle size. Moreover, the oxygen vacancies may also produce magnetic moment by polarizing spins of f electrons of cerium (Ce ions located around oxygen vacancies, which causes ferromagnetism in pure CeO2 samples.

  8. Formation of monodisperse mesoporous silica microparticles via spray-drying.

    Science.gov (United States)

    Waldron, Kathryn; Wu, Winston Duo; Wu, Zhangxiong; Liu, Wenjie; Selomulya, Cordelia; Zhao, Dongyuan; Chen, Xiao Dong

    2014-03-15

    In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Solid-state NMR of inorganic semiconductors.

    Science.gov (United States)

    Yesinowski, James P

    2012-01-01

    Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

  10. NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

    Science.gov (United States)

    This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

  11. Nanoscale Electrochemical Sensing and Processing in Microreactors

    NARCIS (Netherlands)

    Odijk, Mathieu; van den Berg, Albert

    2018-01-01

    In this review, we summarize recent advances in nanoscale electrochemistry, including the use of nanoparticles, carbon nanomaterials, and nanowires. Exciting developments are reported for nanoscale redox cycling devices, which can chemically amplify signal readout. We also discuss promising

  12. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  13. Inorganic liquid scintillator

    International Nuclear Information System (INIS)

    Pavlicek, Z.; Barta, C.; Jursova, L.

    1986-01-01

    An inorganic liquid scintillator is designed which contains 1 to 30 wt.% of an inorganic molecular compound as the basic active component; the compound contains a cation with an atomic number higher than 47 and a halogen anion. The basic inorganic component is dissolved in water or in an organic solvent in form of non-dissociated molecules or self-complexes in which the bond is preserved between the cation and anion components. The light yield from these scintillators ranges between 70 and 150% of the light yield of a standard organic scintillator based on toluene. They are advantageous in that that they allow to increase the water content in the sample to up to 100%. (M.D.)

  14. Nanoscale organic ferroelectric resistive switches

    NARCIS (Netherlands)

    Khikhlovskyi, V.; Wang, R.; Breemen, A.J.J.M. van; Gelinck, G.H.; Janssen, R.A.J.; Kemerink, M.

    2014-01-01

    Organic ferroelectric resistive switches function by grace of nanoscale phase separation in a blend of a semiconducting and a ferroelectric polymer that is sandwiched between metallic electrodes. In this work, various scanning probe techniques are combined with numerical modeling to unravel their

  15. Nanoscale Characterization for the Classroom

    International Nuclear Information System (INIS)

    Carroll, D.L.

    1999-01-01

    This report describes the development of a semester course in 'nano-scale characterization'. The interdisciplinary course is opened to both advanced undergraduate and graduate students with a standard undergraduate preparation in Materials Science, Chemistry, or Physics. The approach is formal rather than the typical 'research seminar' and has a laboratory component

  16. Thorium inorganic gels

    International Nuclear Information System (INIS)

    Genet, M.; Brandel, V.

    1988-01-01

    The optimum pH and concentration values of thorium salts and oxoacids or oxoacid salts which lead to transparent and stable inorganic gels have been determined. The isotherm drying process of the gel at 50 0 C leads successively to a partly dehydrated gel, then, to the formation of an unusual liquid phase and, finally to a dry amorphous solid phase which is still transparent. This kind of transparent inorganic gels and amorphous phase can be used as matrices for spectroscopic studies [fr

  17. Syringe-vacuum microfluidics: A portable technique to create monodisperse emulsions.

    Science.gov (United States)

    Abate, Adam R; Weitz, David A

    2011-03-16

    We present a simple method for creating monodisperse emulsions with microfluidic devices. Unlike conventional approaches that require bulky pumps, control computers, and expertise with device physics to operate devices, our method requires only the microfluidic device and a hand-operated syringe. The fluids needed for the emulsion are loaded into the device inlets, while the syringe is used to create a vacuum at the device outlet; this sucks the fluids through the channels, generating the drops. By controlling the hydrodynamic resistances of the channels using hydrodynamic resistors and valves, we are able to control the properties of the drops. This provides a simple and highly portable method for creating monodisperse emulsions.

  18. Ultrasound-driven Megahertz Faraday Waves for Generation of Monodisperse Micro Droplets and Applications

    Science.gov (United States)

    Tsai, Chen S.; Mao, Rong W.; Lin, Shih K.; Tsai, Shirley C.; Boss, Gerry; Brenner, Matt; Smaldone, Gerry; Mahon, Sari; Shahverdi, Kaveh; Zhu, Yun

    Our theoretical findings on instability of Faraday waves at megahertz (MHz) drive frequency and realization of silicon-based MHz multiple-Fourier horn ultrasonic nozzles (MFHUNs) together have enabled generation of mono-disperse droplets of controllable diameter (2.5-6.0 μm) at very low electrical drive power (generator has imminent application to pulmonary (inhalation) drug delivery and other potential applications. Here an update of advances on analysis and design of the MHz MFHUNs and the underlying physical mechanism for generation of mono-disperse micro droplets, and the nebulizer platform for application to detoxification of cyanide poisoning are presented.

  19. Emulsifier-free emulsion polymerization produces highly charged, monodisperse particles for near infrared photonic crystals.

    Science.gov (United States)

    Reese, Chad E; Asher, Sanford A

    2002-04-01

    We have developed emulsifier-free, emulsion polymerization recipes for the synthesis of highly charged, monodisperse latex particles of diameters between 500 and 1100 nm. These latexes consist of poly[styrene-(co-2-hydroxyethyl methacrylate)] spherical particles whose surfaces are functionalized with sulfate and carboxylic acid groups. These highly charged, monodisperse particles readily self-assemble into robust, three-dimensionally ordered crystalline colloidal array photonic crystals that Bragg diffract light in the near infrared spectral region. By altering the particle number density, the diffraction wavelength can be tuned from approximately 1000 to approximately 4000 nm.

  20. Organic-Inorganic Composites of Semiconductor Nanocrystals for Efficient Excitonics.

    Science.gov (United States)

    Guzelturk, Burak; Demir, Hilmi Volkan

    2015-06-18

    Nanocomposites of colloidal semiconductor nanocrystals integrated into conjugated polymers are the key to soft-material hybrid optoelectronics, combining advantages of both plastics and particles. Synergic combination of the favorable properties in the hybrids of colloidal nanocrystals and conjugated polymers offers enhanced performance and new functionalities in light-generation and light-harvesting applications, where controlling and mastering the excitonic interactions at the nanoscale are essential. In this Perspective, we highlight and critically consider the excitonic interactions in the organic-inorganic nanocomposites to achieve highly efficient exciton transfer through rational design of the nanocomposites. The use of strong excitonic interactions in optoelectronic devices can trigger efficiency breakthroughs in hybrid optoelectronics.

  1. Investigation of nanoscale reinforcement into textile polymers

    Science.gov (United States)

    Khan, Mujibur Rahman

    A dual inclusion strategy for textile polymers has been investigated to increase elastic energy storage capacity of fibers used in high velocity impact applications. Commercial fibers such as Spectra and Dyneema are made from ultra high molecular weight polyethylene (UHMWPE). Dynamic elastic energy of these fibers is still low therefore limiting their wholesale application without a secondary metallic or ceramic component. The idea in this investigation is to develop methodologies so that the elastic energy of polyethylene based fibers can be increased by several folds. This would allow manufacturing of an all-fabric system for high impact applications. The dual inclusion consists of a polymer phase and a nanoscale inorganic phase to polyethylene. The polymer phase was nylon-6 and the inorganic phase was carbon nanotubes (CNTs). Nylon-6 was blended as a minor phase into UHMWPE and was chosen because of its large fracture strain -- almost one order higher than that of UHMWPE. On the other hand, CNTs with their very high strength, modulus, and aspect ratio, contributed to sharing of load and sliding of polymer interfaces as they aligned during extrusion and strain hardening processes. A solution spinning process was developed to produce UHMWPE filaments reinforced with CNTs and nylon-6. The procedure involved dispersing of CNTs into paraffin oil through sonication followed by dissolving polymers into paraffin-CNT solution using a homogenizer. The admixture was fed into a single screw extruder for melt mixing and extrusion through an orifice. The extrudate was rinsed via a hexane bath, stabilized through a heater, and then drawn into a filament winder with controlled stretching. In the next step, the as produced filaments were strain-hardened through repeated loading unloading cycles under tension. Neat and reinforced filaments were characterized through DSC (Differential Scanning Calorimetry), XRD (X-ray Diffraction), Raman Spectroscopy, SEM (Scanning Electron

  2. Systems engineering at the nanoscale

    Science.gov (United States)

    Benkoski, Jason J.; Breidenich, Jennifer L.; Wei, Michael C.; Clatterbaughi, Guy V.; Keng, Pei Yuin; Pyun, Jeffrey

    2012-06-01

    Nanomaterials have provided some of the greatest leaps in technology over the past twenty years, but their relatively early stage of maturity presents challenges for their incorporation into engineered systems. Perhaps even more challenging is the fact that the underlying physics at the nanoscale often run counter to our physical intuition. The current state of nanotechnology today includes nanoscale materials and devices developed to function as components of systems, as well as theoretical visions for "nanosystems," which are systems in which all components are based on nanotechnology. Although examples will be given to show that nanomaterials have indeed matured into applications in medical, space, and military systems, no complete nanosystem has yet been realized. This discussion will therefore focus on systems in which nanotechnology plays a central role. Using self-assembled magnetic artificial cilia as an example, we will discuss how systems engineering concepts apply to nanotechnology.

  3. Creating nanoscale emulsions using condensation.

    Science.gov (United States)

    Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

    2017-11-08

    Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.

  4. Advanced Polymeric and Organic–Inorganic Membranes for Pressure-Driven Processes

    KAUST Repository

    Le, Ngoc Lieu

    2017-02-13

    The state-of-the-art of membranes for reverse osmosis, nanofiltration, and gas separation is shortly reviewed, taking in account the most representative examples currently in application. Emphasis is also done on recent developments of advanced polymeric and organic–inorganic materials for pressure-driven processes. Many of the more recent membranes are not only polymeric but also contain an inorganic phase. Tailoring innovative materials with organic and inorganic phases coexisting in a nanoscale with multifunctionalization is an appealing approach to control at the same time diffusivity and gas solubility. Other advanced materials that are now being considered for membrane development are organic or organic–inorganic self-assemblies, metal-organic frameworks, and different forms of carbon fillers.

  5. Advanced Polymeric and Organic–Inorganic Membranes for Pressure-Driven Processes

    KAUST Repository

    Le, Ngoc Lieu; Phuoc, Duong; Nunes, Suzana Pereira

    2017-01-01

    The state-of-the-art of membranes for reverse osmosis, nanofiltration, and gas separation is shortly reviewed, taking in account the most representative examples currently in application. Emphasis is also done on recent developments of advanced polymeric and organic–inorganic materials for pressure-driven processes. Many of the more recent membranes are not only polymeric but also contain an inorganic phase. Tailoring innovative materials with organic and inorganic phases coexisting in a nanoscale with multifunctionalization is an appealing approach to control at the same time diffusivity and gas solubility. Other advanced materials that are now being considered for membrane development are organic or organic–inorganic self-assemblies, metal-organic frameworks, and different forms of carbon fillers.

  6. Dissecting the structure of surface stabilizer on the dispersion of inorganic nanoparticles in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yong; Yu, Zongzhi; Zheng, Junping, E-mail: jpzheng@tju.edu.cn [Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering (China)

    2017-03-15

    Dispersing inorganic nanoparticles in aqueous solutions is a key requirement for a great variety of products and processes, including carriers in drug delivery or fillers in polymers. To be highly functional in the final product, inorganic particles are required to be finely dispersed in nanoscale. In this study, silica was selected as a representative inorganic particle. Surface stabilizers with different chain length and charged group were designed to reveal the influence of electrostatic and van der Waals forces between silica and stabilizer on the dispersion of silica particles in aqueous medium. Results showed surface stabilizer with longer alkyl chain and charged group exerted best ability to deaggregate silica, leading to a hydrodynamic size of 51.1 nm. Surface stabilizer designing with rational structure is a promising solution for deagglomerating and reducing process time and energy. Giving the designability and adaptability of surface stabilizer, this method is of potential for dispersion of other inorganic nanoparticles.

  7. Dissecting the structure of surface stabilizer on the dispersion of inorganic nanoparticles in aqueous medium

    Science.gov (United States)

    Ding, Yong; Yu, Zongzhi; Zheng, Junping

    2017-03-01

    Dispersing inorganic nanoparticles in aqueous solutions is a key requirement for a great variety of products and processes, including carriers in drug delivery or fillers in polymers. To be highly functional in the final product, inorganic particles are required to be finely dispersed in nanoscale. In this study, silica was selected as a representative inorganic particle. Surface stabilizers with different chain length and charged group were designed to reveal the influence of electrostatic and van der Waals forces between silica and stabilizer on the dispersion of silica particles in aqueous medium. Results showed surface stabilizer with longer alkyl chain and charged group exerted best ability to deaggregate silica, leading to a hydrodynamic size of 51.1 nm. Surface stabilizer designing with rational structure is a promising solution for deagglomerating and reducing process time and energy. Giving the designability and adaptability of surface stabilizer, this method is of potential for dispersion of other inorganic nanoparticles.

  8. Inorganic Constituents in Coal

    Directory of Open Access Journals (Sweden)

    Rađenović A.

    2006-02-01

    Full Text Available Coal contains not only organic matter but also small amounts of inorganic constituents. More thanone hundred different minerals and virtually every element in the periodic table have been foundin coal. Commonly found group minerals in coal are: major (quartz, pyrite, clays and carbonates,minor, and trace minerals. Coal includes a lot of elements of low mass fraction of the orderof w=0.01 or 0.001 %. They are trace elements connected with organic matter or minerals comprisedin coal. The fractions of trace elements usually decrease when the rank of coal increases.Fractions of the inorganic elements are different, depending on the coal bed and basin. A varietyof analytical methods and techniques can be used to determine the mass fractions, mode ofoccurrence, and distribution of organic constituents in coal. There are many different instrumentalmethods for analysis of coal and coal products but atomic absorption spectroscopy – AAS is theone most commonly used. Fraction and mode of occurrence are one of the main factors that haveinfluence on transformation and separation of inorganic constituents during coal conversion.Coal, as an important world energy source and component for non-fuels usage, will be continuouslyand widely used in the future due to its relatively abundant reserves. However, there is aconflict between the requirements for increased use of coal on the one hand and less pollution onthe other. It’s known that the environmental impacts, due to either coal mining or coal usage, canbe: air, water and land pollution. Although, minor components, inorganic constituents can exert asignificant influence on the economic value, utilization, and environmental impact of the coal.

  9. Inorganic Analytical Chemistry

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    The book is a treatise on inorganic analytical reactions in aqueous solution. It covers about half of the elements in the periodic table, i.e. the most important ones : H, Li, B, C, N, O, Na, Mg, Al, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, I, Ba, W,...

  10. Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

    Indian Academy of Sciences (India)

    Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres. K C BARICK and D BAHADUR*. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay,. Mumbai 400 076, India. Abstract. The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 ...

  11. Tri-block copolymers with mono-disperse crystallizable diamide segments: synthesis, analysis and rheological properties

    NARCIS (Netherlands)

    Araichimani, A.; Gaymans, R.J.

    2008-01-01

    Tri-block copolymers with polyether mid-segments and mono-disperse amide end segments were synthesized, analyzed and some properties studied. The end segment was an aromatic diamide (diaramide, TΦB). The polyether mid-segment was a difunctional poly(tetramethylene oxide) (PTMO, 1000 and 2900 g/mol).

  12. Hydrophilic segmented block copolymers based on poly(ethylene oxide) and monodisperse amide segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2007-01-01

    Segmented block copolymers based on poly(ethylene oxide) (PEO) flexible segments and monodisperse crystallizable bisester tetra-amide segments were made via a polycondensation reaction. The molecular weight of the PEO segments varied from 600 to 4600 g/mol and a bisester tetra-amide segment (T6T6T)

  13. Room temperature vortex fluidic synthesis of monodispersed amorphous proto-vaterite.

    Science.gov (United States)

    Peng, Wenhong; Chen, Xianjue; Zhu, Shenmin; Guo, Cuiping; Raston, Colin L

    2014-10-11

    Monodispersed particles of amorphous calcium carbonate (ACC) 90 to 200 nm in diameter are accessible at room temperature in ethylene glycol and water using a vortex fluidic device (VFD). The ACC material is stable for at least two weeks under ambient conditions.

  14. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids.

    Science.gov (United States)

    Pal, Nabanita; Bhaumik, Asim

    2013-03-01

    With the discovery of MCM-41 by Mobil researchers in 1992 the journey of the research on mesoporous materials started and in the 21st century this area of scientific investigation have extended into numerous branches, many of which contribute significantly in emerging areas like catalysis, energy, environment and biomedical research. As a consequence thousands of publications came out in large varieties of national and international journals. In this review, we have tried to summarize the published works on various synthetic pathways and formation mechanisms of different mesoporous materials viz. inorganic, organic-inorganic hybrid and purely organic solids via soft templating pathways. Generation of nanoscale porosity in a solid material usually requires participation of organic template (more specifically surfactants and their supramolecular assemblies) called structure-directing agent (SDA) in the bottom-up chemical reaction process. Different techniques employed for the syntheses of inorganic mesoporous solids, like silicas, metal doped silicas, transition and non-transition metal oxides, mixed oxides, metallophosphates, organic-inorganic hybrids as well as purely organic mesoporous materials like carbons, polymers etc. using surfactants are depicted schematically and elaborately in this paper. Moreover, some of the frontline applications of these mesoporous solids, which are directly related to their functionality, composition and surface properties are discussed at the appropriate places. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Tunable multicolor and enhanced red emission of monodisperse CaF2:Yb3+/Ho3+ microspheres via Mn2+ doping

    Science.gov (United States)

    Wang, Rui; Yuan, Maohui; Zhang, Chaofan; Wang, Hongyan; Xu, Xiaojun

    2018-05-01

    Transition metal ions (e.g. Mn2+) and lanthanide co-doped upconversion (UC) materials have attracted wide attention in recent years due to their promising application in multicolor display. Here, we report the hydrothermal synthesis and characterization of Mn2+ doped monodisperse CaF2:Yb3+/Ho3+ microspheres. The results of X-ray diffraction (XRD) revealed that Mn2+ doping does not change the cubic phase of CaF2 material but will lead to diffraction peaks shifting slightly towards higher angle due to the substitution of larger Ca2+ by the relatively smaller Mn2+. Under the excitation of 980 nm continuous wave (CW) laser, these microspheres exhibit green-yellow-red tuning colors and remarkable enhancement of both red to green ratio (R/G) and red to blue ratio (R/B) when increasing Mn2+ concentration from 0 to 30 mol%. The energy migration process between Ho3+ and Mn2+ was proposed and supported by time-decay and power dependence measurements of Ho3+ UC emission. These upconversion materials may have potential applications in optical devices, color display, nanoscale lasers and biomedical imaging.

  16. Inorganic chemistry and medicine

    International Nuclear Information System (INIS)

    Sadler, P.J.; Guo, Z.

    1999-01-01

    Inorganic chemistry is beginning to have a major impact on medicine. Not only does it offer the prospect of the discovery of truly novel drugs and diagnostic agents, but it promises to make a major contribution to our understanding of the mechanism of action of organic drugs too. Most of this article is concerned with recent developments in medicinal coordination chemistry. The role of metal organic compounds of platinum, titanium, ruthenium, gallium, bismuth, gold, gadolinium, technetium, silver, cobalt in the treatment or diagnosis of common diseases are briefly are examined

  17. Molecular and Nanoscale Engineering of High Efficiency Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jenekhe, Samson A. [Univ. of Washington, Seattle, WA (United States); Ginger, David S. [Univ. of Washington, Seattle, WA (United States); Cao, Guozhong [Univ. of Washington, Seattle, WA (United States)

    2016-01-15

    We combined the synthesis of new polymers and organic-inorganic hybrid materials with new experimental characterization tools to investigate bulk heterojunction (BHJ) polymer solar cells and hybrid organic-inorganic solar cells during the 2007-2010 period (phase I) of this project. We showed that the bulk morphology of polymer/fullerene blend solar cells could be controlled by using either self-assembled polymer semiconductor nanowires or diblock poly(3-alkylthiophenes) as the light-absorbing and hole transport component. We developed new characterization tools in-house, including photoinduced absorption (PIA) spectroscopy, time-resolved electrostatic force microscopy (TR-EFM) and conductive and photoconductive atomic force microscopy (c-AFM and pc-AFM), and used them to investigate charge transfer and recombination dynamics in polymer/fullerene BHJ solar cells, hybrid polymer-nanocrystal (PbSe) devices, and dye-sensitized solar cells (DSSCs); we thus showed in detail how the bulk photovoltaic properties are connected to the nanoscale structure of the BHJ polymer solar cells. We created various oxide semiconductor (ZnO, TiO2) nanostructures by solution processing routes, including hierarchical aggregates and nanorods/nanotubes, and showed that the nanostructured photoanodes resulted in substantially enhanced light-harvesting and charge transport, leading to enhanced power conversion efficiency of dye-sensitized solar cells.

  18. High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

    Science.gov (United States)

    Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

    2014-04-01

    A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 μm diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 μm for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was

  19. Molecular energy dissipation in nanoscale networks of Dentin Matrix Protein 1 is strongly dependent on ion valence

    Science.gov (United States)

    Adams, J; Fantner, G E; Fisher, L W; Hansma, P K

    2008-01-01

    The fracture resistance of biomineralized tissues such as bone, dentin, and abalone is greatly enhanced through the nanoscale interactions of stiff inorganic mineral components with soft organic adhesive components. A proper understanding of the interactions that occur within the organic component, and between the organic and inorganic components, is therefore critical for a complete understanding of the mechanics of these tissues. In this paper, we use Atomic Force Microscope (AFM) force spectroscopy and dynamic force spectroscopy to explore the effect of ionic interactions within a nanoscale system consisting of networks of Dentin Matrix Protein 1 (DMP1) (a component of both bone and dentin organic matrix), a mica surface, and an AFM tip. We find that DMP1 is capable of dissipating large amounts of energy through an ion-mediated mechanism, and that the effectiveness increases with increasing ion valence. PMID:18843380

  20. Molecular energy dissipation in nanoscale networks of dentin matrix protein 1 is strongly dependent on ion valence

    International Nuclear Information System (INIS)

    Adams, J; Fantner, G E; Hansma, P K; Fisher, L W

    2008-01-01

    The fracture resistance of biomineralized tissues such as bone, dentin, and abalone is greatly enhanced through the nanoscale interactions of stiff inorganic mineral components with soft organic adhesive components. A proper understanding of the interactions that occur within the organic component, and between the organic and inorganic components, is therefore critical for a complete understanding of the mechanics of these tissues. In this paper, we use atomic force microscope (AFM) force spectroscopy and dynamic force spectroscopy to explore the effect of ionic interactions within a nanoscale system consisting of networks of dentin matrix protein 1 (DMP1) (a component of both bone and dentin organic matrix), a mica surface and an AFM tip. We find that DMP1 is capable of dissipating large amounts of energy through an ion-mediated mechanism, and that the effectiveness increases with increasing ion valence

  1. Molecular energy dissipation in nanoscale networks of dentin matrix protein 1 is strongly dependent on ion valence

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J; Fantner, G E; Hansma, P K [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Fisher, L W [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD 20892 (United States)], E-mail: adams@physics.ucsb.edu, E-mail: fantner@physics.ucsb.edu, E-mail: lfisher@dir.nidcr.nih.gov, E-mail: prasant@physics.ucsb.edu

    2008-09-24

    The fracture resistance of biomineralized tissues such as bone, dentin, and abalone is greatly enhanced through the nanoscale interactions of stiff inorganic mineral components with soft organic adhesive components. A proper understanding of the interactions that occur within the organic component, and between the organic and inorganic components, is therefore critical for a complete understanding of the mechanics of these tissues. In this paper, we use atomic force microscope (AFM) force spectroscopy and dynamic force spectroscopy to explore the effect of ionic interactions within a nanoscale system consisting of networks of dentin matrix protein 1 (DMP1) (a component of both bone and dentin organic matrix), a mica surface and an AFM tip. We find that DMP1 is capable of dissipating large amounts of energy through an ion-mediated mechanism, and that the effectiveness increases with increasing ion valence.

  2. Tube Formation in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Yan Chenglin

    2008-01-01

    Full Text Available Abstract The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities.

  3. Impact of biogenic nanoscale metals Fe, Cu, Zn and Se on reproductive LV chickens

    International Nuclear Information System (INIS)

    Nguyen, Quy Khiem; Nguyen, Van Kien; Nguyen, Khac Thinh; Nguyen, Duy Dieu; Nguyen, Hoai Chau; Tran, Xuan Tin; Nguyen, Huu Cuong; Phung, Duc Tien

    2015-01-01

    Using biogenic nanoscale metals (Fe, Cu, ZnO, Se) to supplement into diet premix of reproductive LV (a Vietnamese Luong Phuong chicken breed) chickens resulted in certain improvement of poultry farming. The experimental data obtained showed that the farming indices depend mainly on the quantity of nanocrystalline metals which replaced the inorganic mineral component in the feed premix. All four experimental groups with different quantities of the replacement nano component grew and developed normally with livability reaching 91 to 94%, hen’s bodyweight at 38 weeks of age and egg weight ranged from 2.53–2.60 kg/hen and 50.86–51.55 g/egg, respectively. All these farming indices together with laying rate, egg productivity and chick hatchability peaked at group 5 with 25% of nanoscale metals compared to the standard inorganic mineral supplement, while feed consumption was lowest. The results also confirmed that nanocrystalline metals Fe, Cu, ZnO and Se supplemented to chicken feed were able to decrease inorganic minerals in the diet premixes at least four times, allowing animals to more effectively absorb feed minerals, consequently decreasing environmental pollution risks. (paper)

  4. Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

    KAUST Repository

    Li, Erqiang

    2013-12-16

    Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology. Polydimethylsiloxane soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions. The advantages of our method lie in a simple manufacturing procedure, inexpensive processing equipment and flexibility in the surface modification of the designed microfluidic devices. Different types of devices have been designed and tested and the experimental results demonstrated their robustness for preparing monodisperse single, double, triple and multi-component emulsions. © 2014 IOP Publishing Ltd.

  5. Self-diffusion in monodisperse three-dimensional magnetic fluids by molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dobroserdova, A.B. [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); Kantorovich, S.S., E-mail: alla.dobroserdova@urfu.ru [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); University of Vienna, Sensengasse 8, Vienna (Austria)

    2017-06-01

    In the present work we study the self-diffusion behaviour in the three-dimensional monodisperse magnetic fluids using the Molecular Dynamics Simulation and Density Functional Theory. The peculiarity of computer simulation is to study two different systems: dipolar and soft sphere ones. In the theoretical method, it is important to choose the approximation for the main structures, which are chains. We compare the theoretical results and the computer simulation data for the self-diffusion coefficient as a function of the particle volume fraction and magnetic dipole-dipole interaction parameter and find the qualitative and quantitative agreement to be good. - Highlights: • The paper deals with the study of the self-diffusion in monodisperse three-dimensional magnetic fluids. • The theoretical approach contains the free energy density functional minimization. • Computer simulations are performed by the molecular dynamics method. • We have a good qualitative and quantitative agreement between the theoretical results and computer simulation data.

  6. Fabrication of monodisperse magnetic nanoparticles released in solution using a block copolymer template

    Science.gov (United States)

    Morcrette, Mélissa; Ortiz, Guillermo; Tallegas, Salomé; Joisten, Hélène; Tiron, Raluca; Baron, Thierry; Hou, Yanxia; Lequien, Stéphane; Bsiesy, Ahmad; Dieny, Bernard

    2017-07-01

    This paper describes a fabrication process of monodisperse magnetic nanoparticles released in solution, based on combined ‘top-down’ and ‘bottom-up’ approaches. The process involves the use of a self-assembled PS-PMMA block copolymer formed on a sacrificial layer. Such an approach was so far mostly explored for the preparation of patterned magnetic media for ultrahigh density magnetic storage. It is here extended to the preparation of released monodisperse nanoparticles for biomedical applications. A special sacrificial layer had to be developed compatible with the copolymer self-organization. The resulting nanoparticles exhibit very narrow size dispersion (≈7%) and can be good candidates as contrast agents for medical imaging i.e. magnetic resonance imaging or magnetic particle imaging. The approach provides a great freedom in the choice of the particles shapes and compositions. In particular, they can be made of biocompatible magnetic material.

  7. Fabrication of monodisperse magnetic nanoparticles released in solution using a block copolymer template

    International Nuclear Information System (INIS)

    Morcrette, Mélissa; Ortiz, Guillermo; Joisten, Hélène; Dieny, Bernard; Tallegas, Salomé; Baron, Thierry; Bsiesy, Ahmad; Tiron, Raluca; Hou, Yanxia; Lequien, Stéphane

    2017-01-01

    This paper describes a fabrication process of monodisperse magnetic nanoparticles released in solution, based on combined ‘top-down’ and ‘bottom-up’ approaches. The process involves the use of a self-assembled PS-PMMA block copolymer formed on a sacrificial layer. Such an approach was so far mostly explored for the preparation of patterned magnetic media for ultrahigh density magnetic storage. It is here extended to the preparation of released monodisperse nanoparticles for biomedical applications. A special sacrificial layer had to be developed compatible with the copolymer self-organization. The resulting nanoparticles exhibit very narrow size dispersion (≈7%) and can be good candidates as contrast agents for medical imaging i.e. magnetic resonance imaging or magnetic particle imaging. The approach provides a great freedom in the choice of the particles shapes and compositions. In particular, they can be made of biocompatible magnetic material. (paper)

  8. Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-03-24

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than

  9. Harnessing microbial subsurface metal reduction activities to synthesize nanoscale cobalt ferrite with enhanced magnetic properties

    International Nuclear Information System (INIS)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-01-01

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe 2 O 4 ) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of ∼ 10 6 erg cm -3 can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than Fe into the structure

  10. In-site synthesis of monodisperse, oleylamine-capped Ag nanoparticles through microemulsion approach

    Science.gov (United States)

    Chen, Shun; Ju, Yanyun; Guo, Yi; Xiong, Chuanxi; Dong, Lijie

    2017-03-01

    Ag NPs were in-site synthesized through microemulsion method by reducing silver acetate with oleylamine-mediated at 70 °C with highly monodisperse and narrow size from 10 to 20 nm. The synthesis of Ag NPs was aided by oleylamine and the role of oleylamine was researched. This in-site synthesis approach to Ag NPs was reproducibility and high yield more than 80% with stable store about 6 months.

  11. In-site synthesis of monodisperse, oleylamine-capped Ag nanoparticles through microemulsion approach

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shun; Ju, Yanyun [Wuhan University of Technology, School of Materials Science and Engineering (China); Guo, Yi [Wuhan University of Technology, Center for Materials Research and Analysis (China); Xiong, Chuanxi; Dong, Lijie, E-mail: dong@whut.edu.cn [Wuhan University of Technology, School of Materials Science and Engineering (China)

    2017-03-15

    Ag NPs were in-site synthesized through microemulsion method by reducing silver acetate with oleylamine-mediated at 70 °C with highly monodisperse and narrow size from 10 to 20 nm. The synthesis of Ag NPs was aided by oleylamine and the role of oleylamine was researched. This in-site synthesis approach to Ag NPs was reproducibility and high yield more than 80% with stable store about 6 months.

  12. Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape.

    Science.gov (United States)

    Lu, Lehui; Ai, Kelong; Ozaki, Yukihiro

    2008-02-05

    We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

  13. Aqueous dispersion of monodisperse magnetic iron oxide nanocrystals through phase transfer

    International Nuclear Information System (INIS)

    Yu, William W; Chang, Emmanuel; Sayes, Christie M; Drezek, Rebekah; Colvin, Vicki L

    2006-01-01

    A facile method was developed for completely transferring high quality monodisperse iron oxide nanocrystals from organic solvents to water. The as-prepared aqueous dispersions of iron oxide nanocrystals were extremely stable and could be functionalized for bioconjugation with biomolecules. These iron oxide nanocrystals showed negligible cytotoxicity to human breast cancer cells (SK-BR-3) and human dermal fibroblast cells. This method is general and versatile for many organic solvent-synthesized nanoparticles, including fluorescent semiconductor nanocrystals

  14. Preparation of monodisperse porous silica particles using poly(glycidyl methacrylate) microspheres as a template

    Czech Academy of Sciences Publication Activity Database

    Grama, Silvia; Horák, Daniel

    2015-01-01

    Roč. 64, Suppl. 1 (2015), S11-S17 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : microspheres * monodisperse * silica Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64%20Suppl%201/64_S11.pdf

  15. Temperature dependence of exchange anisotropy in monodisperse cobalt nanoparticles with a cobalt oxide shell

    International Nuclear Information System (INIS)

    Spasova, M.; Wiedwald, U.; Farle, M.; Radetic, T.; Dahmen, U.; Hilgendorff, M.; Giersig, M.

    2004-01-01

    Exchange anisotropy was studied by SQUID magnetometry on an array of monodisperse colloidal nanoparticles consisting of a 7-8 nm diameter FCC Co core covered with a 2-2.5 nm thick FCC CoO shell. Temperature-dependent measurements of the exchange bias field show that the exchange anisotropy vanishes when a magnetic field was applied during cooling below 150 K. The suppression of exchange anisotropy is due to uncompensated interfacial antiferromagnetic spins

  16. Monodisperse microbeads of hypercrosslinked polystyrene for liquid and supercritical fluid chromatography

    Science.gov (United States)

    Tsyurupa, M. P.; Blinnikova, Z. K.; Il'in, M. M.; Davankov, V. A.; Parenago, O. O.; Pokrovskii, O. I.; Usovich, O. I.

    2015-11-01

    Monodisperse styrene-divinylbenzene (1 wt %) copolymer microbeads are obtained via the elaborate method of high-productivity precipitation polymerization. The crosslinking of this copolymer with chloromethyl methyl ether in the presence of Friedel-Crafts catalyst yields porous hypercrosslinked polymers with degrees of crosslinking that range from 200 to 500%. Microbead sorbents are shown to be suited for selective stationary phases for high-performance liquid chromatography and supercritical fluid chromatography.

  17. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    Energy Technology Data Exchange (ETDEWEB)

    Wen Li [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Lin Zhonghua [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Gu Pingying [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Zhou Jianzhang [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Yao Bingxing [Xiamen University, School of Life Sciences (China); Chen Guoliang; Fu Jinkun, E-mail: wenli_1976@163.co [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China)

    2009-02-15

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 {sup o}C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 {+-} 0.8 nm size were formed by using Bacillus megatherium D01.

  18. Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

    International Nuclear Information System (INIS)

    Shen, Shou-Cang; Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai; Tan, Reginald B.H.

    2011-01-01

    Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: → Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. → Strong positive charge was created by aminopropyl-modification. → Capability for immobilization of negatively charged protein was enhanced. → Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by 13 C and 29 Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

  19. Synthesis of monodisperse silver nanoparticles for ink-jet printed flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhiliang; Zhang Xingye; Xin Zhiqing; Deng Mengmeng; Wen Yongqiang; Song Yanlin, E-mail: zhangxy@iccas.ac.cn, E-mail: ylsong@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Lab of Organic Solids, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-21

    In this study, monodisperse silver nanoparticles were synthesized with a new reduction system consisting of adipoyl hydrazide and dextrose at ambient temperature. By this facile and rapid approach, high concentration monodisperse silver nanoparticles were obtained on a large scale at low protectant/AgNO{sub 3} mass ratio which was highly beneficial to low cost and high conductivity. Based on the synthesized monodisperse silver nanoparticles, conductive inks were prepared with water, ethanol and ethylene glycol as solvents, and were expected to be more environmentally friendly. A series of electrocircuits were fabricated by ink-jet printing silver nanoparticle ink on paper substrate with a commercial printer, and they had low resistivity in the range of 9.18 x 10{sup -8}-8.76 x 10{sup -8} {Omega} m after thermal treatment at 160 {sup 0}C for 30 min, which was about five times that of bulk silver (1.586 x 10{sup -8} {Omega} m). Moreover, a radio frequency identification (RFID) antenna was fabricated by ink-jet printing, and 6 m wireless identification was realized after an Alien higgs-3 chip was mounted on the printed antenna by the flip-chip method. These flexible electrocircuits produced by ink-jet printing would have enormous potential for low cost electrodes and sensor devices.

  20. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    International Nuclear Information System (INIS)

    Wen Li; Lin Zhonghua; Gu Pingying; Zhou Jianzhang; Yao Bingxing; Chen Guoliang; Fu Jinkun

    2009-01-01

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 o C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

  1. Synthesis of monodisperse silver nanoparticles for ink-jet printed flexible electronics

    International Nuclear Information System (INIS)

    Zhang Zhiliang; Zhang Xingye; Xin Zhiqing; Deng Mengmeng; Wen Yongqiang; Song Yanlin

    2011-01-01

    In this study, monodisperse silver nanoparticles were synthesized with a new reduction system consisting of adipoyl hydrazide and dextrose at ambient temperature. By this facile and rapid approach, high concentration monodisperse silver nanoparticles were obtained on a large scale at low protectant/AgNO 3 mass ratio which was highly beneficial to low cost and high conductivity. Based on the synthesized monodisperse silver nanoparticles, conductive inks were prepared with water, ethanol and ethylene glycol as solvents, and were expected to be more environmentally friendly. A series of electrocircuits were fabricated by ink-jet printing silver nanoparticle ink on paper substrate with a commercial printer, and they had low resistivity in the range of 9.18 x 10 -8 -8.76 x 10 -8 Ω m after thermal treatment at 160 0 C for 30 min, which was about five times that of bulk silver (1.586 x 10 -8 Ω m). Moreover, a radio frequency identification (RFID) antenna was fabricated by ink-jet printing, and 6 m wireless identification was realized after an Alien higgs-3 chip was mounted on the printed antenna by the flip-chip method. These flexible electrocircuits produced by ink-jet printing would have enormous potential for low cost electrodes and sensor devices.

  2. Optimization of a simple technique for preparation of monodisperse poly(lactide-co-glycolide) nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Fuminori, E-mail: fuminoito@spice.ocn.ne.jp [Tokyo Metropolitan University, Department of Applied Chemistry, Graduate School of Urban Environmental Sciences (Japan)

    2016-09-15

    In this study, we report the optimization of a solvent evaporation technique for preparing monodisperse poly-(lactide-co-glycolide) (PLGA) nanospheres, from a mixture of solvents composed of ethanol and PVA solution. Various experimental conditions were investigated in order to control the particle size and size distribution of the nanospheres. In addition, nanospheres containing rifampicin (RFP, an antituberculosis drug), were prepared using PLGA of various molecular weights, to study the effects of RFP as a model hydrophobic drug. The results showed that a higher micro-homogenizer stirring rate facilitated the preparation of monodisperse PLGA nanospheres with a low coefficient of variation (~20 %), with sizes below 200 nm. Increasing the PLGA concentration from 0.1 to 0.5 g resulted in an increase in the size of the obtained nanospheres from 130 to 174 nm. The molecular weight of PLGA had little effect on the particle sizes and particle size distributions of the nanospheres. However, the drug loading efficiencies of the obtained RFP/PLGA nanospheres decreased when the molecular weight of PLGA was increased. Based on these experiments, an optimized technique was established for the preparation of monodisperse PLGA nanospheres, using the method developed by the authors.Graphical Abstract.

  3. Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Shou-Cang, E-mail: shen_shoucang@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Tan, Reginald B.H., E-mail: reginald_tan@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Department of Chemical and Biomolecular Engineering, The National University of Singapore, 4 Engineering Drive 4, Singapore 117576 (Singapore)

    2011-10-15

    Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: {yields} Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. {yields} Strong positive charge was created by aminopropyl-modification. {yields} Capability for immobilization of negatively charged protein was enhanced. {yields} Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by {sup 13}C and {sup 29}Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

  4. Synthesis of highly monodisperse particles composed of a magnetic core and fluorescent shell.

    Science.gov (United States)

    Nagao, Daisuke; Yokoyama, Mikio; Yamauchi, Noriko; Matsumoto, Hideki; Kobayashi, Yoshio; Konno, Mikio

    2008-09-02

    Highly monodisperse particles composed of a magnetic silica core and fluorescent polymer shell were synthesized with a combined technique of heterocoagulation and soap-free emulsion polymerization. Prior to heterocoagulation, monodisperse, submicrometer-sized silica particles were prepared with the Stober method, and magnetic nanoparticles were prepared with a modified Massart method in which a cationic silane coupling agent of N-trimethoxysilylpropyl- N, N, N-trimethylammonium chloride was added just after coprecipitation of Fe (2+) and Fe (3+). The silica particles with negative surface potential were heterocoagulated with the magnetic nanoparticles with positive surface potential. The magnetic silica particles obtained with the heterocoagulation were treated with sodium silicate to modify their surfaces with silica. In the formation of a fluorescent polymer shell onto the silica-coated magnetic silica cores, an amphoteric initiator of 2,2'-azobis[ N-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057) was used to control the colloidal stability of the magnetic cores during the polymer coating. The polymerization of St in the presence of a hydrophobic fluorophore of pyrene could coat the cores with fluorescent polymer shells, resulting in monodisperse particles with a magnetic silica core and fluorescent polymer shell. Measurements of zeta potential for the composite particles in different pH values indicated that the composite particles had an amphoteric property originating from VA-057 initiator.

  5. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T. [Sandia National Laboratories, Albuquerque, NM (United States)] [and others

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  6. Inorganic Halogen Oxidizer Research

    Science.gov (United States)

    1979-02-16

    Inorganic Chemistry. Vol. 14. No. 9. 1975 Karl 0. Christ¢ (21) L. J. Basile . P. LaBonvillk. J. R. Ferraro, and J. M. Williams. J. Claim. (38) K. 0. Chriae. E... basils of a nonplanar structure of symmetry CI, are revised for six fundamental frequencies. Imalredetle either the 1:2 adduct N 2F4.2SbF5 or the 1:3...8217 in mT are 7 2.1 for B, facility. We aba thank L. K. White and R. L. Belford 111.0 for C, 55.0 for N, and 17100 for F, and the atomic aniso- trop’c

  7. Modern Trends in Inorganic Chemistry

    Indian Academy of Sciences (India)

    Administrator

    The series of symposia on 'Modern Trends in Inorganic Chemistry' (MTIC), which began in 1985 at the Indian Association for Cultivation of Science, Calcutta has evolved into a forum for the Inorganic Chemistry fraternity of the country to meet every two years and discuss the current status and future projections of research in.

  8. Nanoscale biophysics of the cell

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2018-01-01

    Macroscopic cellular structures and functions are generally investigated using biological and biochemical approaches. But these methods are no longer adequate when one needs to penetrate deep into the small-scale structures and understand their functions. The cell is found to hold various physical structures, molecular machines, and processes that require physical and mathematical approaches to understand and indeed manipulate them. Disorders in general cellular compartments, perturbations in single molecular structures, drug distribution therein, and target specific drug-binding, etc. are mostly physical phenomena. This book will show how biophysics has revolutionized our way of addressing the science and technology of nanoscale structures of cells, and also describes the potential for manipulating the events that occur in them.

  9. Nanoscale cryptography: opportunities and challenges.

    Science.gov (United States)

    Masoumi, Massoud; Shi, Weidong; Xu, Lei

    2015-01-01

    While most of the electronics industry is dependent on the ever-decreasing size of lithographic transistors, this scaling cannot continue indefinitely. To improve the performance of the integrated circuits, new emerging and paradigms are needed. In recent years, nanoelectronics has become one of the most important and exciting forefront in science and engineering. It shows a great promise for providing us in the near future with many breakthroughs that change the direction of technological advances in a wide range of applications. In this paper, we discuss the contribution that nanotechnology may offer to the evolution of cryptographic hardware and embedded systems and demonstrate how nanoscale devices can be used for constructing security primitives. Using a custom set of design automation tools, it is demonstrated that relative to a conventional 45-nm CMOS system, performance gains can be obtained up to two orders of magnitude reduction in area and up to 50 % improvement in speed.

  10. Nanoscale Mixing of Soft Solids

    International Nuclear Information System (INIS)

    Choi, Soo-Hyung; Lee, Sangwoo; Soto, Haidy E.; Lodge, Timothy P.; Bates, Frank S.

    2011-01-01

    Assessing the state of mixing on the molecular scale in soft solids is challenging. Concentrated solutions of micelles formed by self-assembly of polystyrene-block-poly(ethylene-alt-propylene) (PS-PEP) diblock copolymers in squalane (C 30 H 62 ) adopt a body-centered cubic (bcc) lattice, with glassy PS cores. Utilizing small-angle neutron scattering (SANS) and isotopic labeling ( 1 H and 2 H (D) polystyrene blocks) in a contrast-matching solvent (a mixture of squalane and perdeuterated squalane), we demonstrate quantitatively the remarkable fact that a commercial mixer can create completely random mixtures of micelles with either normal, PS(H), or deuterium-labeled, PS(D), cores on a well-defined bcc lattice. The resulting SANS intensity is quantitatively modeled by the form factor of a single spherical core. These results demonstrate both the possibility of achieving complete nanoscale mixing in a soft solid and the use of SANS to quantify the randomness.

  11. Size and Crystallinity in Protein-Templated Inorganic Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, Craig C.; Uchida, Masaki; Reichhardt, Courtney; Harrington, Richard; Kang, Sebyung; Klem, Michael T.; Parise, John B.; Douglas, Trevor (SBU); (Montana)

    2010-12-01

    Protein cages such as ferritins and virus capsids have been used as containers to synthesize a wide variety of protein-templated inorganic nanoparticles. While identification of the inorganic crystal phase has been successful in some cases, very little is known about the detailed nanoscale structure of the inorganic component. We have used pair distribution function analysis of total X-ray scattering to measure the crystalline domain size in nanoparticles of ferrihydrite, {gamma}-Fe{sub 2}O{sub 3}, Mn{sub 3}O{sub 4}, CoPt, and FePt grown inside 24-meric ferritin cages from H. sapiens and P. furiosus. The material properties of these protein-templated nanoparticles are influenced by processes at a variety of length scales: the chemistry of the material determines the precise arrangement of atoms at very short distances, while the interior volume of the protein cage constrains the maximum nanoparticle size attainable. At intermediate length scales, the size of coherent crystalline domains appears to be constrained by the arrangement of crystal nucleation sites on the interior of the cage. On the basis of these observations, some potential synthetic strategies for the control of crystalline domain size in protein-templated nanoparticles are suggested.

  12. Inorganic Fullerene-Like Nanoparticles and Inorganic Nanotubes

    Directory of Open Access Journals (Sweden)

    Reshef Tenne

    2014-11-01

    Full Text Available Fullerene-like nanoparticles (inorganic fullerenes; IF and nanotubes of inorganic layered compounds (inorganic nanotubes; INT combine low dimensionality and nanosize, enhancing the performance of corresponding bulk counterparts in their already known applications, as well as opening new fields of their own [1]. This issue gathers articles from the diverse area of materials science and is devoted to fullerene-like nanoparticles and nanotubes of layered sulfides and boron nitride and collects the most current results obtained at the interface between fundamental research and engineering.[...

  13. Nanoscale science and nanotechnology education in Africa ...

    African Journals Online (AJOL)

    Nanoscale science and nanotechnology education in Africa: importance and ... field with its footing in chemistry, physics, molecular biology and engineering. ... career/business/development opportunities, risks and policy challenges that would ...

  14. Patterning high explosives at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Nafday, Omkar A.; Pitchimani, Rajasekar; Weeks, Brandon L. [Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409 (United States); Haaheim, Jason [NanoInk Inc., 8025 Lamon Ave., Skokie, IL 60077 (United States)

    2006-10-15

    For the first time, we have shown that spin coating and Dip pen nanolithography (DPN trademark) are simple methods of preparing energetic materials such as PETN and HMX on the nanoscale, requiring no heating of the energetic material. Nanoscale patterning has been demonstrated by the DPN method while continuous thin films were produced using the spin coating method. Results are presented for preparing continuous PETN thin films of nanometer thickness by the spin coating method and for controlling the architecture of arbitrary nanoscale patterns of PETN and HMX by the DPN method. These methods are simple for patterning energetic materials and can be extended beyond PETN and HMX, opening the door for fundamental studies at the nanoscale. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  15. Quantum Transport Simulations of Nanoscale Materials

    KAUST Repository

    Obodo, Tobechukwu Joshua

    2016-01-01

    -performance supercomputers allow us to control and exploit their microscopic properties at the atomic scale, hence making it possible to design novel nanoscale molecular devices with interesting features (e.g switches, rectifiers, negative differential conductance, and high

  16. Nanoscale drug delivery for targeted chemotherapy.

    Science.gov (United States)

    Xin, Yong; Huang, Qian; Tang, Jian-Qin; Hou, Xiao-Yang; Zhang, Pei; Zhang, Long Zhen; Jiang, Guan

    2016-08-28

    Despite significant improvements in diagnostic methods and innovations in therapies for specific cancers, effective treatments for neoplastic diseases still represent major challenges. Nanotechnology as an emerging technology has been widely used in many fields and also provides a new opportunity for the targeted delivery of cancer drugs. Nanoscale delivery of chemotherapy drugs to the tumor site is highly desirable. Recent studies have shown that nanoscale drug delivery systems not only have the ability to destroy cancer cells but may also be carriers for chemotherapy drugs. Some studies have demonstrated that delivery of chemotherapy via nanoscale carriers has greater therapeutic benefit than either treatment modality alone. In this review, novel approaches to nanoscale delivery of chemotherapy are described and recent progress in this field is discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Cancer risk from inorganics

    International Nuclear Information System (INIS)

    Swierenga, S.H.; Gilman, J.P.; McLean, J.R.

    1987-01-01

    Inorganic metals and minerals for which there is evidence of carcinogenicity are identified. The risk of cancer from contact with them in the work place, the general environment, and under conditions of clinical (medical) exposure is discussed. The evidence indicates that minerals and metals most often influence cancer development through their action as cocarcinogens. The relationship between the physical form of mineral fibers, smoking and carcinogenic risk is emphasized. Metals are categorized as established (As, Be, Cr, Ni), suspected (Cd, Pb) and possible carcinogens, based on the existing in vitro, animal experimental and human epidemiological data. Cancer risk and possible modes of action of elements in each class are discussed. Views on mechanisms that may be responsible for the carcinogenicity of metals are updated and analysed. Some specific examples of cancer risks associated with the clinical use of potentially carcinogenic metals and from radioactive pharmaceuticals used in therapy and diagnosis are presented. Questions are raised as to the effectiveness of conventional dosimetry in accurately measuring risk from radiopharmaceuticals. 302 references

  18. Nanoscale thermal transport. II. 2003–2012

    OpenAIRE

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2013-01-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of th...

  19. Fast heat flux modulation at the nanoscale

    OpenAIRE

    van Zwol, P. J.; Joulain, K.; Abdallah, P. Ben; Greffet, J. J.; Chevrier, J.

    2011-01-01

    We introduce a new concept for electrically controlled heat flux modulation. A flux contrast larger than 10 dB is expected with switching time on the order of tens of nanoseconds. Heat flux modulation is based on the interplay between radiative heat transfer at the nanoscale and phase change materials. Such large contrasts are not obtainable in solids, or in far field. As such this opens up new horizons for temperature modulation and actuation at the nanoscale.

  20. Inorganic chemistry of earliest sediments

    International Nuclear Information System (INIS)

    Ochiai, E.I.

    1983-01-01

    A number of inorganic elements are now known to be essential to organisms. Chemical evolutionary processes involving carbon, hydrogen, nitrogen and oxygen have been studied intensively and extensively, but the other essential elements have been rather neglected in the studies of chemical and biological evolution. This article attempts to assess the significance of inorganic chemistry in chemical and biological evolutionary processes on the earth. Emphasis is placed on the catalytic effects of inorganic elements and compounds, and also on possible studies on the earliest sediments, especially banded iron formation and stratabound copper from the inorganic point of view in the hope of shedding some light on the evolution of the environment and the biological effects on it. (orig./WL)

  1. Passive films at the nanoscale

    International Nuclear Information System (INIS)

    Maurice, Vincent; Marcus, Philippe

    2012-01-01

    Highlights: ► Nanoscale data on growth, structure and local properties of passive films reviewed. ► Preferential role of defects of passive films on the corrosion resistance emphasized. ► Effect of grain boundaries on local electronic properties shown by new data. ► Use of atomistic modeling to test mechanistic hypotheses illustrated. - Abstract: The nanometer scale chemical and structural aspects of ultrathin oxide passive films providing self-protection against corrosion to metals and alloys in aqueous environments are reviewed. Data on the nucleation and growth of 2D anodic oxide films, details on the atomic structure and nanostructure of 3D passive films, the preferential role of surface step edges in dissolution in the passive state and the preferential role of grain boundaries of the passive films in passivity breakdown are presented. Future perspectives are discussed, and exemplified by new data obtained on the relationship between the nanostructure of oxide passive films and their local electronic properties. Atomistic corrosion modeling by ab initio density functional theory (DFT) is illustrated by the example of interactions of chloride ions with hydroxylated oxide surfaces, including the role of surface step edges. Data obtained on well-defined substrate surfaces with surface analytical techniques are emphasized.

  2. Essentials of inorganic materials synthesis

    CERN Document Server

    Rao, C N R

    2015-01-01

    This compact handbook describes all the important methods of synthesis employed today for synthesizing inorganic materials. Some features: Focuses on modern inorganic materials with applications in nanotechnology, energy materials, and sustainability Synthesis is a crucial component of materials science and technology; this book provides a simple introduction as well as an updated description of methods Written in a very simple style, providing references to the literature to get details of the methods of preparation when required

  3. A review of organic and inorganic biomaterials for neural interfaces.

    Science.gov (United States)

    Fattahi, Pouria; Yang, Guang; Kim, Gloria; Abidian, Mohammad Reza

    2014-03-26

    Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.

  4. Force chains in monodisperse spherical particle assemblies: Three-dimensional measurements using neutrons

    Science.gov (United States)

    Wensrich, C. M.; Kisi, E. H.; Luzin, V.; Garbe, U.; Kirstein, O.; Smith, A. L.; Zhang, J. F.

    2014-10-01

    The full triaxial stress state within individual particles in a monodisperse spherical granular assembly has been measured. This was made possible by neutron imaging and computed tomography combined with neutron diffraction strain measurement techniques and associated stress reconstruction. The assembly in question consists of 549 precision steel ball bearings under an applied axial load of 85 MPa in a cylindrical die. Clear evidence of force chains was observed in terms of both the shape of the probability distribution function for normal stresses and the network formed by highly loaded particles. An extensive analysis of the source and magnitude of uncertainty in these measurements is also presented.

  5. High Performance Affinity Chromatography of Antithrombin III Based on Monodisperse Poly (glycidyl methacrylate) Beads

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new approach for the separation of antithrombin III with high performance affinity chromatography (HPAC) was described. A novel monodisperse,non-porous,cross-linked poly (glycidyl methacrylate) beads (PGMA) were used as the affinity support. With the water-soluble carbodiimide,heparin was linked covalently to amino-PGMA-beads,which was prepared by amination of PGMA. The adsorbent obtained exhibits high binding activity to antithrombin III (ATIII),good resolution and excellent mechanical properties and can be used under high flow rate.

  6. Synthesis of Monodisperse CdSe QDs using Controlled Growth Temperatures

    International Nuclear Information System (INIS)

    Noor Razinah Rahmat; Akrajas Ali Umar; Muhammad Yahya; Muhamad Mat Salleh; Mohammad Hafizuddin Jumali

    2011-01-01

    The effect of growth temperatures on size of CdSe quantum dots (QDs) has been investigated. CdSe QDs were synthesized using thermolysis of organometallics precursor route using wet chemical method. The growth temperature was varied from 260-310 degree Celsius with growth period fixed at 60 s. As the growth temperature increased, the monodispersed CdSe QDs with diameter in the range 3-7 nm were obtained. Both absorption and PL spectra of the QDs revealed a strong red-shift supporting the increment size of QDs with the rise of growth temperature. (author)

  7. The Synthesis, Characterization and Catalytic Reaction Studies of Monodisperse Platinum Nanoparticles in Mesoporous Oxide Materials

    Energy Technology Data Exchange (ETDEWEB)

    Rioux, Robert M. [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    A catalyst design program was implemented in which Pt nanoparticles, either of monodisperse size and/or shape were synthesized, characterized and studied in a number of hydrocarbon conversion reactions. The novel preparation of these materials enables exquisite control over their physical and chemical properties that could be controlled (and therefore rationally tuned) during synthesis. The ability to synthesize rather than prepare catalysts followed by thorough characterization enable accurate structure-function relationships to be elucidated. This thesis emphasizes all three aspects of catalyst design: synthesis, characterization and reactivity studies. The precise control of metal nanoparticle size, surface structure and composition may enable the development of highly active and selective heterogeneous catalysts.

  8. Can a droplet break up under flow without elongating? Fragmentation of smectic monodisperse droplets

    Science.gov (United States)

    Courbin, L.; Engl, W.; Panizza, P.

    2004-06-01

    We study the fragmentation under shear flow of smectic monodisperse droplets at high volume fraction. Using small angle light scattering and optical microscopy, we reveal the existence of a break-up mechanism for which the droplets burst into daughter droplets of the same size. Surprisingly, this fragmentation process, which is strain controlled and occurs homogeneously in the cell, does not require any transient elongation of the droplets. Systematic experiments as a function of the initial droplet size and the applied shear rate show that the rupture is triggered by an instability of the inner droplet structure.

  9. Note: A simple vibrating orifice monodisperse droplet generator using a hard drive actuator arm

    Energy Technology Data Exchange (ETDEWEB)

    Kosch, Sebastian, E-mail: skosch@mie.utoronto.ca, E-mail: ashgriz@mie.utoronto.ca; Ashgriz, Nasser, E-mail: skosch@mie.utoronto.ca, E-mail: ashgriz@mie.utoronto.ca [Department of Industrial and Mechanical Engineering, University of Toronto, Toronto, Ontario M5S 3G8 (Canada)

    2015-04-15

    We propose that the rotary voice coil actuators found in magnetic hard drives are fit to supercede loudspeakers as expedient vibration sources in the laboratory setting. A specific use case is the excitation of a liquid jet to induce controlled breakup into monodisperse droplets. Like loudspeakers, which are typically used for prototyping such devices, hard drive actuators are cheap and ubiquitous, but they are less unwieldy and supply greater amplitudes without producing noise. Frequencies between 0 and 17 kHz, and likely beyond, can be reproduced reliably. No machining tools or amplifying electronics are needed for the construction and operation of the presented droplet generator.

  10. Nanoscale Molecules Under Thermodynamic Control:" Digestive Ripening" or " Nanomachining"

    Energy Technology Data Exchange (ETDEWEB)

    Klabunde, Kenneth J. [Kansas State Univ., Manhattan, KS (United States)

    2015-06-04

    Overall Research Goals and Specific Objectives: Nanoscale materials are becoming ubiquitous in science and engineering, and are found widely in nature. However, their formation processes and uniquely high chemical reactivities are not understood well, indeed are often mysterious. Over recent years, a number of research teams have described nanoparticle synthesis, and aging, thermal treatment, or etching times have been mentioned. We have used the terms “digestive ripening” and “nanomachining” and have suggested that thermodynamics plays an important part in the size adjustment to monodisperse arrays being formed. Since there is scant theoretical understanding of digestive ripening, the overall goal in our research is to learn what experimental parameters (ligand used, temperature, solvent, time) are most important, how to control nanoparticle size and shape after initial crude nanoparticles have been synthesized, and gain better understanding of the chemical mechanism details. Specific objectives for the past twentynine months since the grant began have been to (1) Secure and train personnel;as of 2011, a postdoc Deepa Jose, female from the Indian Institute of Science in Bangalore, India; Yijun Sun, a second year graduate student, female from China; and Jessica Changstrom, female from the USA, GK12 fellow (program for enhancing teaching ability) are actively carrying out research. (2) Find out what happens to sulfur bound hydrogen of thiol when it interacts with gold nanoparticles. Our findings are discussed in detail later. (3) Determine the effect of particle size, shape, and temperature on dodecyl thiol assited digestive ripening of gold nanoparticles. See our discussions later. (4) To understand in detail the ligand interaction in molecular clusters and nanoparticles (5) Determine the effect of chain length of amines on Au nanoparticle size under digestive ripening conditions (carbon chain length varied from 4-18). (6) Determine the catalytic activity

  11. Nanoscale ferroelectrics and multiferroics key processes and characterization issues, and nanoscale effects

    CERN Document Server

    Alguero, Miguel

    2016-01-01

    This book reviews the key issues in processing and characterization of nanoscale ferroelectrics and multiferroics, and provides a comprehensive description of their properties, with an emphasis in differentiating size effects of extrinsic ones like boundary or interface effects. Recently described nanoscale novel phenomena are also addressed. Organized into three parts it addresses key issues in processing (nanostructuring), characterization (of the nanostructured materials) and nanoscale effects. Taking full advantage of the synergies between nanoscale ferroelectrics and multiferroics, it covers materials nanostructured at all levels, from ceramic technologies like ferroelectric nanopowders, bulk nanostructured ceramics and thick films, and magnetoelectric nanocomposites, to thin films, either polycrystalline layer heterostructures or epitaxial systems, and to nanoscale free standing objects with specific geometries, such as nanowires and tubes at different levels of development. The book is developed from t...

  12. Fracture and Toughening of Composites of Polymers and Nanoscale Inorganic and Organic Fillers

    National Research Council Canada - National Science Library

    Chung, Neal

    2001-01-01

    The objectives of the project were to investigate the mechanical properties and particularly the fracture mechanisms of a number of nanocomposites, and to discover possible approaches to their toughening...

  13. Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

    1999-01-01

    Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

  14. Monodispersed macroporous architecture of nickel-oxide film as an anode material for thin-film lithium-ion batteries

    International Nuclear Information System (INIS)

    Wu, Mao-Sung; Lin, Ya-Ping

    2011-01-01

    A nickel-oxide film with monodispersed open macropores was prepared on a stainless-steel substrate by electrophoretic deposition of a polystyrene-sphere monolayer followed by anodic electrodeposition of nickel oxy-hydroxide. The deposited films convert to cubic nickel oxide after annealing at 400 o C for 1 h. Galvanostatic charge and discharge results indicate that the nickel-oxide film with monodispersed open macropores is capable of delivering a higher capacity than the bare nickel-oxide film, especially in high-rate charge and discharge processes. The lithiation capacity of macroporous nickel oxide reaches 1620 mA h g -1 at 1 C current discharge and decreases to 990 mA h g -1 at 15 C current discharge. The presence of monodispersed open macropores in the nickel-oxide film might facilitate the electrolyte penetration, diffusion, and migration. Electrochemical reactions between nickel oxide and lithium ions are therefore markedly improved by this tailored film architecture.

  15. On the relationship between the dynamic behavior and nanoscale staggered structure of the bone

    Science.gov (United States)

    Qwamizadeh, Mahan; Zhang, Zuoqi; Zhou, Kun; Zhang, Yong Wei

    2015-05-01

    Bone, a typical load-bearing biological material, composed of ordinary base materials such as organic protein and inorganic mineral arranged in a hierarchical architecture, exhibits extraordinary mechanical properties. Up to now, most of previous studies focused on its mechanical properties under static loading. However, failure of the bone occurs often under dynamic loading. An interesting question is: Are the structural sizes and layouts of the bone related or even adapted to the functionalities demanded by its dynamic performance? In the present work, systematic finite element analysis was performed on the dynamic response of nanoscale bone structures under dynamic loading. It was found that for a fixed mineral volume fraction and unit cell area, there exists a nanoscale staggered structure at some specific feature size and layout which exhibits the fastest attenuation of stress waves. Remarkably, these specific feature sizes and layouts are in excellent agreement with those experimentally observed in the bone at the same scale, indicating that the structural size and layout of the bone at the nanoscale are evolutionarily adapted to its dynamic behavior. The present work points out the importance of dynamic effect on the biological evolution of load-bearing biological materials.

  16. Characterization of Monodispersed Iron Oxide Nanocrystals by XAS and MCD measurement

    International Nuclear Information System (INIS)

    Kim, J.-Y.; Noh, H.-J.; Park, B.-G.; Kim, T.-Y.; Park, J.-H.; Hyeon, T.; Park, J.; Kang, E.

    2004-01-01

    Full text: Nanoparticles have attracted so much attention because of their potential technological applications and abundance of scientifically interesting issues. In particular, magnetic nanoparticles are considered to be applicable to various magnetic devices such as terabit memory, ferrofluids, magnetocaloric refrigeration systems, blood cells, etc. With the development of nano-technology, variation of physical properties as a function of particle size is one of the most important issues, but has been rarely explored because of difficulty of the size control in synthesizing nanoparticles. Recently, some of us successfully synthesized high crystalline and monodisperse maghemite nanoparticles without a size selection process and research in this field seems to be promoted by one step. In this report, we present a systematic characterization of the monodispersed nanocrystalline γ - Fe 2 O 3 with the diameter of 13, 8 and 4 nm by measuring the x-ray absorption spectroscopy (XAS) and the x-ray magnetic circular dichroism(XMCD) spectra on Fe L edge. The spectra of the 4 nm nanoparticles are very similar to those of maghemite (γ - Fe 2 O 3 ). However, the spectra become close to those of magnetite (Fe 3 O 4 ) as the particle size becomes 8 and 13 nm. Considering that the maghemite and magnetite have the same spinel structure with different Fe vacancies, these results can be explained that the surface of nanoparticles has more vacancies than the core part, indicating that surface disorder increases as the particle size decreases

  17. An alternative route towards monodisperse CdS quantum dots for hybrid solar cells

    International Nuclear Information System (INIS)

    Cao, Fengfeng; Wang, Hao; Xia, Zhouhui; Dai, Xiao; Cong, Shan; Dong, Chao; Sun, Baoquan; Lou, Yanhui; Sun, Yinghui; Zhao, Jie; Zou, Guifu

    2015-01-01

    Monodisperse CdS quantum dots (QDs) are synthesized by thermal decomposition of organic complexes in the system of the cost-effective commercial 0 # diesel at 200 °C. The prepared CdS QDs have a good dispersion and high crystallization. When the CdS QDs are doped into the blends of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6, 6)C61 (PCBM) for hybrid solar cells (HSCs), the HSCs achieve about 25% increase of power conversion efficiency in comparison to the reference device without the CdS QDs. The improvement of the cell performance mainly attributes to the increased short-circuit current density arising from the absorption enhancement in the wavelength range of 350–550 nm by introducing the synthesized CdS QDs into the P3HT: PCBM active layer. - Highlights: • Monodisperse CdS quantum dots. • A cost-effective route to synthesize crystalline CdS quantum dots. • CdS quantum dots based hybrid solar cells with power conversion efficiency enhancement

  18. An alternative route towards monodisperse CdS quantum dots for hybrid solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Fengfeng; Wang, Hao [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Xia, Zhouhui [Institute of Functional Nano and Soft Materials, Soochow University, Suzhou 215123 (China); Dai, Xiao; Cong, Shan [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Dong, Chao [Department of Chemistry and Biology, University of New Mexico, ABQ 87120 (United States); Sun, Baoquan [Institute of Functional Nano and Soft Materials, Soochow University, Suzhou 215123 (China); Lou, Yanhui, E-mail: yhlou@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Sun, Yinghui; Zhao, Jie [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Zou, Guifu, E-mail: zouguifu@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China)

    2015-01-15

    Monodisperse CdS quantum dots (QDs) are synthesized by thermal decomposition of organic complexes in the system of the cost-effective commercial 0{sup #} diesel at 200 °C. The prepared CdS QDs have a good dispersion and high crystallization. When the CdS QDs are doped into the blends of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6, 6)C61 (PCBM) for hybrid solar cells (HSCs), the HSCs achieve about 25% increase of power conversion efficiency in comparison to the reference device without the CdS QDs. The improvement of the cell performance mainly attributes to the increased short-circuit current density arising from the absorption enhancement in the wavelength range of 350–550 nm by introducing the synthesized CdS QDs into the P3HT: PCBM active layer. - Highlights: • Monodisperse CdS quantum dots. • A cost-effective route to synthesize crystalline CdS quantum dots. • CdS quantum dots based hybrid solar cells with power conversion efficiency enhancement.

  19. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  20. Lock and Key Colloids through Polymerization-Induced Buckling of Monodispersed Silicon Oil Droplets

    Science.gov (United States)

    Sacanna, Stefano; Irvine, William T. M.; Chaikin, Paul M.; Pine, David J.

    2010-03-01

    Colloidal particles can spontaneously associate into larger structured aggregates when driven by selective and directional interactions. Colloidal organization can be programmed by engineering shapes and interactions of basic building blocks in a manner similar to molecular self-assembly. Examples of successful strategies that allow non-trivial assembly of particles include template-directed patterning, capillary forces and, most commonly, the functionalization of the particle surfaces with ``sticky patches'' of biological or synthetic molecules. The level of complexity of the realizable assemblies, increases when particles with well defined shape anisotropies are used. In particular depletion forces and specific surface treatments in combination with non spherical particles have proven to be powerful tools to self-assembly complex microstructures. We describe a simple, high yield, synthetic pathway to fabricate monodisperse hybrid silica spheres with well defined cavities. Because the particle morphologies are reproducible and tunable with precision, the resulting particles can be used as basic building blocks in the assembly of larger monodisperse clusters. This is demonstrated using depletion to drive the self-assembly.

  1. Linear theory on temporal instability of megahertz faraday waves for monodisperse microdroplet ejection.

    Science.gov (United States)

    Tsai, Shirley C; Tsai, Chen S

    2013-08-01

    A linear theory on temporal instability of megahertz Faraday waves for monodisperse microdroplet ejection based on mass conservation and linearized Navier-Stokes equations is presented using the most recently observed micrometer- sized droplet ejection from a millimeter-sized spherical water ball as a specific example. The theory is verified in the experiments utilizing silicon-based multiple-Fourier horn ultrasonic nozzles at megahertz frequency to facilitate temporal instability of the Faraday waves. Specifically, the linear theory not only correctly predicted the Faraday wave frequency and onset threshold of Faraday instability, the effect of viscosity, the dynamics of droplet ejection, but also established the first theoretical formula for the size of the ejected droplets, namely, the droplet diameter equals four-tenths of the Faraday wavelength involved. The high rate of increase in Faraday wave amplitude at megahertz drive frequency subsequent to onset threshold, together with enhanced excitation displacement on the nozzle end face, facilitated by the megahertz multiple Fourier horns in resonance, led to high-rate ejection of micrometer- sized monodisperse droplets (>10(7) droplets/s) at low electrical drive power (<;1 W) with short initiation time (<;0.05 s). This is in stark contrast to the Rayleigh-Plateau instability of a liquid jet, which ejects one droplet at a time. The measured diameters of the droplets ranging from 2.2 to 4.6 μm at 2 to 1 MHz drive frequency fall within the optimum particle size range for pulmonary drug delivery.

  2. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2013-12-23

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  3. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; von Meerwall, Ernst D.; Koerner, Hilmar; Vaia, Richard A.; Fernandes, Nikhil J.; Giannelis, Emmanuel P.

    2013-01-01

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  4. Self-assembly of inorganic nanoparticles: Ab ovo

    Science.gov (United States)

    Kotov, Nicholas A.

    2017-09-01

    There are numerous remarkable studies related to the self-organization of polymers, coordination compounds, microscale particles, biomolecules, macroscale particles, surfactants, and reactive molecules on surfaces. The focus of this paper is on the self-organization of nanoscale inorganic particles or simply nanoparticles (NPs). Although there are fascinating and profound discoveries made with other self-assembling structures, the ones involving NPs deserve particular attention because they (a) are omnipresent in Nature; (b) have relevance to numerous disciplines (physics, chemistry, biology, astronomy, Earth sciences, and others); (c) embrace most of the features, geometries, and intricacies observed for the self-organization of other chemical species; (d) offer new tools for studies of self-organization phenomena; and (e) have a large economic impact, extending from energy and construction industries, to optoelectronics, biomedical technologies, and food safety. Despite the overall success of the field it is necessary to step back from its multiple ongoing research venues and consider two questions: What is self-assembly of nanoparticles? and Why do we need to study it? The reason to bring them up is to achieve greater scientific depth in the understanding of these omnipresent phenomena and, perhaps, deepen their multifaceted impact. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  5. Preparation of inorganic hydrophobic catalysts

    International Nuclear Information System (INIS)

    Yang, Yong; Wang, Heyi; Du, Yang

    2009-04-01

    In order to catalyse the oxidation of tritium gas, two inorganic hydrophobic catalysts are prepared. Under room temperature, the catalysed oxidation ratio of 0.3%-1% (V/V) hydrogen gas in air is higher than 95%. Pt-II inorganic hydrophobic catalysts has obviously better catalysing ability than Pt-PTFE and lower ability than Pt-SDB in H 2 -HTO isotopic exchange, because the pressure resistence of Pt-II is much higher than Pt-SDB, it can be used to the CECE cell of heavy water detritium system. (authors)

  6. Nanoscale phase-change materials and devices

    International Nuclear Information System (INIS)

    Zheng, Qinghui; Wang, Yuxi; Zhu, Jia

    2017-01-01

    Phase-change materials (PCMs) that can reversibly transit between crystalline and amorphous phases have been widely used for data-storage and other functional devices. As PCMs scale down to nanoscale, the properties and transition procedures can vary, bringing both challenges and opportunities in scalability. This article describes the physical structures, properties and applications of nanoscale phase-change materials and devices. The limitations and performance of scaling properties in phase-change materials and the recent progress and challenges in phase-change devices are presented. At the end, some emerging applications related to phase-change materials are also introduced. (topical review)

  7. Atomic nanoscale technology in the nuclear industry

    CERN Document Server

    Woo, Taeho

    2011-01-01

    Developments at the nanoscale are leading to new possibilities and challenges for nuclear applications in areas ranging from medicine to international commerce to atomic power production/waste treatment. Progress in nanotech is helping the nuclear industry slash the cost of energy production. It also continues to improve application reliability and safety measures, which remain a critical concern, especially since the reactor disasters in Japan. Exploring the new wide-ranging landscape of nuclear function, Atomic Nanoscale Technology in the Nuclear Industry details the breakthroughs in nanosca

  8. Nanoscale phase-change materials and devices

    Science.gov (United States)

    Zheng, Qinghui; Wang, Yuxi; Zhu, Jia

    2017-06-01

    Phase-change materials (PCMs) that can reversibly transit between crystalline and amorphous phases have been widely used for data-storage and other functional devices. As PCMs scale down to nanoscale, the properties and transition procedures can vary, bringing both challenges and opportunities in scalability. This article describes the physical structures, properties and applications of nanoscale phase-change materials and devices. The limitations and performance of scaling properties in phase-change materials and the recent progress and challenges in phase-change devices are presented. At the end, some emerging applications related to phase-change materials are also introduced.

  9. Molecular modeling of inorganic compounds

    National Research Council Canada - National Science Library

    Comba, Peter; Hambley, Trevor W; Martin, Bodo

    2009-01-01

    ... mechanics to inorganic and coordination compounds. Initially, simple metal complexes were modeled, but recently the field has been extended to include organometallic compounds, catalysis and the interaction of metal ions with biological macromolecules. The application of molecular mechanics to coordination compounds is complicated by the numbe...

  10. Inorganic nanomedicine--part 1.

    Science.gov (United States)

    Sekhon, Bhupinder S; Kamboj, Seema R

    2010-08-01

    Inorganic nanomedicine refers to the use of inorganic or hybrid nanomaterials and nanosized objects to achieve innovative medical breakthroughs for drug and gene discovery and delivery, discovery of biomarkers, and molecular diagnostics. Potential uses for fluorescent quantum dots include cell labeling, biosensing, in vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. Biocompatible quantum dot conjugates have been used successfully for sentinel lymph node mapping, tumor targeting, tumor angiogenesis imaging, and metastatic cell tracking. Magnetic nanowires applications include biosensing and construction of nucleic acids sensors. Magnetic cell therapy is used for the repair of blood vessels. Magnetic nanoparticles (MNPs) are important for magnetic resonance imaging, drug delivery, cell labeling, and tracking. Superparamagnetic iron oxide nanoparticles are used for hyperthermic treatment of tumors. Multifunctional MNPs applications include drug and gene delivery, medical imaging, and targeted drug delivery. MNPs could have a vital role in developing techniques to simultaneously diagnose, monitor, and treat a wide range of common diseases and injuries. From the clinical editor: This review serves as an update about the current state of inorganic nanomedicine. The use of inorganic/hybrid nanomaterials and nanosized objects has already resulted in innovative medical breakthroughs for drug/gene discovery and delivery, discovery of biomarkers and molecular diagnostics, and is likely to remain one of the most prolific fields of nanomedicine. 2010 Elsevier Inc. All rights reserved.

  11. James Moir as Inorganic Chemist

    African Journals Online (AJOL)

    NICO

    KEYWORDS. Inorganic chemistry, gold, atomic theory, history of chemistry. .... Figure 2 (a) shows Moir's model for the C atom, where the black circles represent the ..... Na filled the hole in the F atom, both becoming ions even in the crystal state ...

  12. Determining Inorganic and Organic Carbon.

    Science.gov (United States)

    Koistinen, Jaana; Sjöblom, Mervi; Spilling, Kristian

    2017-11-21

    Carbon is the element which makes up the major fraction of lipids and carbohydrates, which could be used for making biofuel. It is therefore important to provide enough carbon and also follow the flow into particulate organic carbon and potential loss to dissolved organic forms of carbon. Here we present methods for determining dissolved inorganic carbon, dissolved organic carbon, and particulate organic carbon.

  13. Dynamics of polyelectrolyte adsorption and colloidal flocculation upon mixing studied using mono-dispersed polystyrene latex particles

    NARCIS (Netherlands)

    Feng, Lili; Cohen Stuart, Martien; Adachi, Yasuhisa

    2015-01-01

    The dynamic behavior of polyelectrolytes just after their encounter with the surface of bare colloidal particles is analyzed, using the flocculation properties of mono-dispersed polystyrene latex (PSL) particles. Applying a Standardized Colloid Mixing (SCM) approach, effects of ionic strength and

  14. Rapid Synthesis of Highly Monodisperse Au x Ag 1− x Alloy Nanoparticles via a Half-Seeding Approach

    KAUST Repository

    Chng, Ting Ting; Polavarapu, Lakshminarayana; Xu, Qing Hua; Ji, Wei; Zeng, Hua Chun

    2011-01-01

    Gold-silver alloy AuxAg1-x is an important class of functional materials promising new applications across a wide array of technological fields. In this paper, we report a fast and facile synthetic protocol for preparation of highly monodisperse Aux

  15. Plasma-assisted synthesis of monodispersed and robust Ruthenium ultrafine nanocatalysts for organosilane oxidation and oxygen evolution reactions

    NARCIS (Netherlands)

    Gnanakumar, E.S.; Ng, W.; Filiz, B.C.; Rothenberg, G.; Wang, S.; Xu, H.; Pastor-Pérez, L.; Pastor-Blas, M.M.; Sepúlveda-Escribano, A.; Yan, N.; Shiju, N.R.

    2017-01-01

    We report a facile and general approach for preparing ultrafine ruthenium nanocatalysts by using a plasma-assisted synthesis at <100 °C. The resulting Ru nanoparticles are monodispersed (typical size 2 nm) and remain that way upon loading onto carbon and TiO2 supports. This gives robust catalysts

  16. Dynamic structural disorder in supported nanoscale catalysts

    International Nuclear Information System (INIS)

    Rehr, J. J.; Vila, F. D.

    2014-01-01

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale

  17. Benchtop Nanoscale Patterning Using Soft Lithography

    Science.gov (United States)

    Meenakshi, Viswanathan; Babayan, Yelizaveta; Odom, Teri W.

    2007-01-01

    This paper outlines several benchtop nanoscale patterning experiments that can be incorporated into undergraduate laboratories or advanced high school chemistry curricula. The experiments, supplemented by an online video lab manual, are based on soft lithographic techniques such as replica molding, micro-molding in capillaries, and micro-contact…

  18. Dynamic structural disorder in supported nanoscale catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rehr, J. J.; Vila, F. D. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States)

    2014-04-07

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale.

  19. Traceable nanoscale measurement at NML-SIRIM

    International Nuclear Information System (INIS)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-01-01

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  20. Traceable nanoscale measurement at NML-SIRIM

    Science.gov (United States)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-06-01

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  1. Enhanced nanoscale friction on fluorinated graphene.

    Science.gov (United States)

    Kwon, Sangku; Ko, Jae-Hyeon; Jeon, Ki-Joon; Kim, Yong-Hyun; Park, Jeong Young

    2012-12-12

    Atomically thin graphene is an ideal model system for studying nanoscale friction due to its intrinsic two-dimensional (2D) anisotropy. Furthermore, modulating its tribological properties could be an important milestone for graphene-based micro- and nanomechanical devices. Here, we report unexpectedly enhanced nanoscale friction on chemically modified graphene and a relevant theoretical analysis associated with flexural phonons. Ultrahigh vacuum friction force microscopy measurements show that nanoscale friction on the graphene surface increases by a factor of 6 after fluorination of the surface, while the adhesion force is slightly reduced. Density functional theory calculations show that the out-of-plane bending stiffness of graphene increases up to 4-fold after fluorination. Thus, the less compliant F-graphene exhibits more friction. This indicates that the mechanics of tip-to-graphene nanoscale friction would be characteristically different from that of conventional solid-on-solid contact and would be dominated by the out-of-plane bending stiffness of the chemically modified graphene. We propose that damping via flexural phonons could be a main source for frictional energy dissipation in 2D systems such as graphene.

  2. Neuromorphic computing with nanoscale spintronic oscillators.

    Science.gov (United States)

    Torrejon, Jacob; Riou, Mathieu; Araujo, Flavio Abreu; Tsunegi, Sumito; Khalsa, Guru; Querlioz, Damien; Bortolotti, Paolo; Cros, Vincent; Yakushiji, Kay; Fukushima, Akio; Kubota, Hitoshi; Yuasa, Shinji; Stiles, Mark D; Grollier, Julie

    2017-07-26

    Neurons in the brain behave as nonlinear oscillators, which develop rhythmic activity and interact to process information. Taking inspiration from this behaviour to realize high-density, low-power neuromorphic computing will require very large numbers of nanoscale nonlinear oscillators. A simple estimation indicates that to fit 10 8 oscillators organized in a two-dimensional array inside a chip the size of a thumb, the lateral dimension of each oscillator must be smaller than one micrometre. However, nanoscale devices tend to be noisy and to lack the stability that is required to process data in a reliable way. For this reason, despite multiple theoretical proposals and several candidates, including memristive and superconducting oscillators, a proof of concept of neuromorphic computing using nanoscale oscillators has yet to be demonstrated. Here we show experimentally that a nanoscale spintronic oscillator (a magnetic tunnel junction) can be used to achieve spoken-digit recognition with an accuracy similar to that of state-of-the-art neural networks. We also determine the regime of magnetization dynamics that leads to the greatest performance. These results, combined with the ability of the spintronic oscillators to interact with each other, and their long lifetime and low energy consumption, open up a path to fast, parallel, on-chip computation based on networks of oscillators.

  3. Inelastic transport theory for nanoscale systems

    DEFF Research Database (Denmark)

    Frederiksen, Thomas

    2007-01-01

    This thesis describes theoretical and numerical investigations of inelastic scat- tering and energy dissipation in electron transport through nanoscale sys- tems. A computational scheme, based on a combination of density functional theory (DFT) and nonequilibrium Green’s functions (NEGF), has been...

  4. Effects of nanoscale contacts to graphene

    NARCIS (Netherlands)

    Franklin, A.D.; Han, S.-J.; Bol, A.A.; Haensch, W.

    2011-01-01

    Understanding and optimizing transport between metal contacts and graphene is one of the foremost challenges for graphene devices. In this letter, we present the first results on the effects of reducing contact dimensions to the nanoscale in single-layer graphene transistors. Using noninvasive

  5. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...

  6. Selective nanoscale growth of lattice mismatched materials

    Science.gov (United States)

    Lee, Seung-Chang; Brueck, Steven R. J.

    2017-06-20

    Exemplary embodiments provide materials and methods of forming high-quality semiconductor devices using lattice-mismatched materials. In one embodiment, a composite film including one or more substantially-single-particle-thick nanoparticle layers can be deposited over a substrate as a nanoscale selective growth mask for epitaxially growing lattice-mismatched materials over the substrate.

  7. Nanoscale thermal transport: Theoretical method and application

    Science.gov (United States)

    Zeng, Yu-Jia; Liu, Yue-Yang; Zhou, Wu-Xing; Chen, Ke-Qiu

    2018-03-01

    With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very important issue. In addition, the heat generated by the electronic devices mostly diffuses to the air in the form of waste heat, which makes the thermoelectric energy conversion also an important issue for nowadays. In recent years, the thermal transport properties in nanoscale systems have attracted increasing attention in both experiments and theoretical calculations. In this review, we will discuss various theoretical simulation methods for investigating thermal transport properties and take a glance at several interesting thermal transport phenomena in nanoscale systems. Our emphasizes will lie on the advantage and limitation of calculational method, and the application of nanoscale thermal transport and thermoelectric property. Project supported by the Nation Key Research and Development Program of China (Grant No. 2017YFB0701602) and the National Natural Science Foundation of China (Grant No. 11674092).

  8. Traceable nanoscale measurement at NML-SIRIM

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Ahmad M.; Abdul Hapip, A. I. [National Metrology Laboratory SIRIM Berhad (NML-SIRIM), Lot PT 4803, Bandar Baru Salak Tinggi, 43900 Sepang (Malaysia)

    2012-06-29

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  9. Hybrid polymer-inorganic photovoltaic cells

    NARCIS (Netherlands)

    Beek, W.J.E.; Janssen, R.A.J.; Merhari, L.

    2009-01-01

    Composite materials made from organic conjugated polymers and inorganic semiconductors such as metal oxides attract considerable interest for photovoltaic applications. Hybrid polymer-inorganic solar cells offer the opportunity to combine the beneficial properties of the two materials in charge

  10. DNA-imprinted polymer nanoparticles with monodispersity and prescribed DNA-strand patterns

    Science.gov (United States)

    Trinh, Tuan; Liao, Chenyi; Toader, Violeta; Barłóg, Maciej; Bazzi, Hassan S.; Li, Jianing; Sleiman, Hanadi F.

    2018-02-01

    As colloidal self-assembly increasingly approaches the complexity of natural systems, an ongoing challenge is to generate non-centrosymmetric structures. For example, patchy, Janus or living crystallization particles have significantly advanced the area of polymer assembly. It has remained difficult, however, to devise polymer particles that associate in a directional manner, with controlled valency and recognition motifs. Here, we present a method to transfer DNA patterns from a DNA cage to a polymeric nanoparticle encapsulated inside the cage in three dimensions. The resulting DNA-imprinted particles (DIPs), which are 'moulded' on the inside of the DNA cage, consist of a monodisperse crosslinked polymer core with a predetermined pattern of different DNA strands covalently 'printed' on their exterior, and further assemble with programmability and directionality. The number, orientation and sequence of DNA strands grafted onto the polymeric core can be controlled during the process, and the strands are addressable independently of each other.

  11. Nonthermal plasma synthesis of size-controlled, monodisperse, freestanding germanium nanocrystals

    International Nuclear Information System (INIS)

    Gresback, Ryan; Holman, Zachary; Kortshagen, Uwe

    2007-01-01

    Germanium nanocrystals may be of interest for a variety of electronic and optoelectronic applications including photovoltaics, primarily due to the tunability of their band gap from the infrared into the visible range of the spectrum. This letter discusses the synthesis of monodisperse germanium nanocrystals via a nonthermal plasma approach which allows for precise control of the nanocrystal size. Germanium crystals are synthesized from germanium tetrachloride and hydrogen entrained in an argon background gas. The crystal size can be varied between 4 and 50 nm by changing the residence times of crystals in the plasma between ∼30 and 440 ms. Adjusting the plasma power enables one to synthesize fully amorphous or fully crystalline particles with otherwise similar properties

  12. Monodisperse, submicrometer-scale platinum colloidal spheres with high electrocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lixue; Wang, Liang; Guo, Shaojun; Zhai, Junfeng; Dong, Shaojun; Wang, Erkang [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 130022 Jilin, Changchun (China)

    2009-02-15

    Monodisperse, submicrometer-scale platinum (Pt) colloidal spheres were prepared through a simple direct chemical reduction of p-phenylenediamine (PPD)-chloroplatinic acid (H{sub 2}PtCl{sub 6}) coordination polymer colloids. It was found that the prepared Pt colloids had the similar size and morphology with their coordination polymer precursors, and the prepared Pt colloids with rough surfaces were three-dimensional (3D) structured assemblies of high-density small Pt nanoparticles. The electrochemical experiments confirmed that the prepared Pt colloids possessed a high electrocatalytic activity towards mainly four-electron reduction of dioxygen to water, making the prepared Pt colloids potential candidates for the efficient cathode material in fuel cells. (author)

  13. Synthesis of Monodisperse Walnut-Like SnO2 Spheres and Their Photocatalytic Performances

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2015-01-01

    Full Text Available Novel walnut-like SnO2 spheres have been synthesized using a one-step hydrothermal reaction with SnCl2·2H2O and KOH as raw materials. The morphology, microstructure, and optical properties of the products were characterized by X-ray powder diffraction (XRD, Raman spectrum, scanning electron microscopy (SEM, transmission electron microscopy (TEM, selected area electron diffraction (SAED, and ultraviolet-visible (UV-Vis absorption spectroscopy. The detailed studies revealed that these synthesized spheres are highly monodisperse and have a uniform size of approximately 250 nm. Photocatalytic activity of the prepared SnO2 spheres was evaluated by the degradation of methylene orange. The synthesized SnO2 spheres exhibited excellent photocatalytic degradation. In addition, a possible formation mechanism of the walnut-like nanostructures was proposed based on reaction time-dependent experiments.

  14. Synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity

    Science.gov (United States)

    Bindhu, M. R.; Umadevi, M.

    2013-01-01

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri.

  15. Monodispersed ZIF-8 particles with enhanced performance for CO2 adsorption and heterogeneous catalysis

    Science.gov (United States)

    Guan, Yebin; Shi, Juanjuan; Xia, Ming; Zhang, Jun; Pang, Zhenfeng; Marchetti, Alessandro; Wang, Xiaohong; Cai, Jingsong; Kong, Xueqian

    2017-11-01

    Monodispersed zeolitic imidazolate frameworks (ZIFs) were prepared with a simple method using dimethylsulfoxide (DMSO) as solvent. This method yields ZIF-8 nanoparticles with a narrow particle size distribution of 90-110 nm and the dispersion is highly stable against agglomeration. These particles have larger nanosized porosity and enhanced CO2 adsorption capability compared to ZIF-8 prepared with different solvents such as methanol or N, N-dimethyl formamide. Their uniform size and surface chemistry also lead to superior performance in the Knoevenagel condensation reactions. The ZIF-8 nanoparticles possess high thermal stability up to 550 °C and the preparation steps are easy for scaling up which are favorable for industrial applications.

  16. Growth of monodisperse nanocrystals of cerium oxide during synthesis and annealing

    International Nuclear Information System (INIS)

    Ghosh, Swapankumar; Divya, Damodaran; Remani, Kottayilpadi C.; Sreeremya, Thadathil S.

    2010-01-01

    Monodisperse cerium oxide nanocrystals have been successfully synthesised using simple ammonia precipitation technique from cerium(III) nitrate solution at different temperatures in the range 35-80 o C. The activation energy for growth of CeO 2 nanocrystals during the precipitation is calculated as 11.54 kJ/mol using Arrhenius plot. Average crystal diameter was obtained from XRD analysis, HR-TEM and light scattering (PCS). The analysis of size data from HR-TEM images and PCS clearly indicated the formation of highly crystalline CeO 2 particles in narrow size range. CeO 2 nanocrystals precipitated at 35 o C were further annealed at temperatures in the range 300-700 o C. The activation energy for crystal growth during annealing is also calculated and is close to the reported values. An effort is made to predict the mechanism of crystal growth during the precipitation and annealing.

  17. Microwave Synthesis of Nearly Monodisperse Core/Multishell Quantum Dots with Cell Imaging Applications

    Directory of Open Access Journals (Sweden)

    Xu Hengyi

    2010-01-01

    Full Text Available Abstract We report in this article the microwave synthesis of relatively monodisperse, highly crystalline CdSe quantum dots (QDs overcoated with Cd0.5Zn0.5S/ZnS multishells. The as-prepared QDs exhibited narrow photoluminescence bandwidth as the consequence of homogeneous size distribution and uniform crystallinity, which was confirmed by transmission electron microscopy. A high photoluminescence quantum yield up to 80% was measured for the core/multishell nanocrystals. Finally, the resulting CdSe/Cd0.5Zn0.5S/ZnS core/multishell QDs have been successfully applied to the labeling and imaging of breast cancer cells (SK-BR3.

  18. Microscopy evidence of the face-centered cubic arrangement of monodisperse polystyrene nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hui [School of Science, Beijing Jiaotong University, Beijing 100044 (China)]. E-mail: zhanghui14305@sohu.com; Duan Renguan [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li Fan [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Tang Qing [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080 (China); Li Wenchao [Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2007-07-01

    This paper reports a scanning electron microscopy (SEM) investigation of polystyrene artificial opal achieved through self-assembly of monodisperse polystyrene nanospheres with a diameter of 250 nm from colloidal suspension after being ambient dried. A detailed analysis of the SEM images verifies that the face-centered cubic (fcc) phase is the most stable one for the polystyrene opal prepared. This finding provides a strong support for, by using polystyrene opal as template, fabricating a photonic crystal with inverse fcc structure of full band gap if the refractive index contrast is higher than 2.8 and the filling fraction of the high index materials is between 0.2 and 0.3.

  19. Microscopy evidence of the face-centered cubic arrangement of monodisperse polystyrene nanospheres

    International Nuclear Information System (INIS)

    Zhang Hui; Duan Renguan; Li Fan; Tang Qing; Li Wenchao

    2007-01-01

    This paper reports a scanning electron microscopy (SEM) investigation of polystyrene artificial opal achieved through self-assembly of monodisperse polystyrene nanospheres with a diameter of 250 nm from colloidal suspension after being ambient dried. A detailed analysis of the SEM images verifies that the face-centered cubic (fcc) phase is the most stable one for the polystyrene opal prepared. This finding provides a strong support for, by using polystyrene opal as template, fabricating a photonic crystal with inverse fcc structure of full band gap if the refractive index contrast is higher than 2.8 and the filling fraction of the high index materials is between 0.2 and 0.3

  20. A novel approach for preparation of micrometer-sized, monodisperse dimple and hemispherical polystyrene particles.

    Science.gov (United States)

    Tanaka, Takuya; Komatsu, Yoshifumi; Fujibayashi, Teruhisa; Minami, Hideto; Okubo, Masayoshi

    2010-03-16

    Micrometer-sized, monodisperse dimple and hemispherical polystyrene (PS) particles were successfully prepared by heating (55-70 degrees C) of spherical PS particles dispersed in methanol/water media (40/60 to 80/20, w/w) in the presence of decane droplets, and subsequent cooling down to room temperature. Decane was absorbed by the PS particles during the heating process. Decane-absorbed PS particles phase-separated into PS and decane phases in the inside during the cooling process, and eventually dimple and/or hemispherical particles were formed by removal of the decane phase from phase-separated PS/decane particles by evaporation. The size of the dimple, which is determined by the volume of decane phase-separated from decane-absorbed PS particles during the cooling process, increased with increases in the heating temperature and the methanol content.

  1. Measurement and interpretation of growth and evaporation of monodispersed droplets in a shock tube

    Science.gov (United States)

    Peters, F.; Paikert, B.

    1994-01-01

    A special gasdynamic shock tube process in combination with a Mie light scattering method is used to study growth and subsequent evaporation of monodispersed droplets carried in argon or air. The droplets are generated by homogeneous nucleation and observed in the micrometer range (0.15-6 micrometer radius). Droplet concentrations range from 10-1000/cu mm. Four different substances, i.e. water, n-propanol, methanol and n-hexane are tested for a wide range of properties. A model covering the entire range between large (Kn much greater than 1) and small Knudsen numbers (K much less than 1) is applied to interpret the experimental data. Excellent agreement is found.

  2. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    Science.gov (United States)

    Wen, Li; Lin, Zhonghua; Gu, Pingying; Zhou, Jianzhang; Yao, Bingxing; Chen, Guoliang; Fu, Jinkun

    2009-02-01

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 °C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

  3. Synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity.

    Science.gov (United States)

    Bindhu, M R; Umadevi, M

    2013-01-15

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Production and characterization of monodisperse uranium particles for nuclear safeguards applications

    International Nuclear Information System (INIS)

    Knott, Alexander

    2016-01-01

    Environmental sampling is a very effective measure to detect undeclared nuclear activities. Generally, samples are taken as swipe samples on cotton. These swipes contain minute quantities of particulates which have an inherent signature of their production and release scenario. These inspection samples are assessed for their morphology, elemental composition and their isotopic vectors. Mass spectrometry plays a crucial role in determining the isotopic ratios of uranium. Method validation and instrument calibration with well-characterized quality control (QC)-materials, reference materials (RMs) and certified reference materials (CRMs) ensures reliable data output. Currently, the availability of suitable well defined microparticles containing uranium and plutonium reference materials is very limited. Primarily, metals, oxides and various uranium and plutonium containing solutions are commercially available. Therefore, the IAEA's Safeguards Analytical Services (SGAS) cooperates with the Institute of Nuclear Waste Management and Reactor Safety (IEK-6) at the Forschungszentrum Juelich GmbH in a joint task entitled ''Production of Particle Reference Materials''. The work presented in this thesis has been partially funded by the IAEA, Forschungszentrum Juelich GmbH and the Federal Ministry of Economic Affairs and Energy (BMWi) through the ''Joint Program on the Technical Development and Further Improvement of IAEA Safeguards between the Government of the Federal Republic of Germany and the IAEA''. The first step towards monodisperse microparticles was the development of pure uranium oxide particles made from certified reference materials. The focus of the dissertation is (1) the implementation of a working setup to produce monodisperse uranium oxide particles and (2) the characterization of these particles towards the application as QC-material. Monodisperse uranium oxide particles were produced by spray pyrolysis. It was demonstrated that the particle size can be

  5. One-pot template-free synthesis of monodisperse hollow hydrogel microspheres and their resulting properties.

    Science.gov (United States)

    Lim, Hyung-Seok; Kwon, Eunji; Lee, Moonjoo; Moo Lee, Young; Suh, Kyung-Do

    2013-08-01

    Monodisperse poly(methacrylic acid/ethyleneglycoldimethacrylate) (MAA/EGDMA) hollow microcapsules, which exhibit pH-responsive behavior, are prepared by diffusion of cationic surfactants and hydrophobic interaction. During the association of the negatively charged hydrogel microspheres and an oppositely charged surfactant (cetyltrimethylammonium bromide, CTA(+)B), the hydrophobic polymer-surfactant complexes that form are separated from the internal water; consequently, a hollow structure can be formed. Confocal laser scanning microscopy, UV spectro-scopy and zeta potential are employed to study the formation of the hollow structure during the diffusion of the cationic surfactant. The controlled release behavior of methylene blue as a model drug from the as-prepared poly(MAA/EGDMA) microcapsules with a hollow structure is investigated under different pH conditions. The hollow structure can be retained, even during repetitive pH changes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Parameterizing the competition between homogeneous and heterogeneous freezing in cirrus cloud formation – monodisperse ice nuclei

    Directory of Open Access Journals (Sweden)

    D. Barahona

    2009-01-01

    Full Text Available We present a parameterization of cirrus cloud formation that computes the ice crystal number and size distribution under the presence of homogeneous and heterogeneous freezing. The parameterization is very simple to apply and is derived from the analytical solution of the cloud parcel equations, assuming that the ice nuclei population is monodisperse and chemically homogeneous. In addition to the ice distribution, an analytical expression is provided for the limiting ice nuclei number concentration that suppresses ice formation from homogeneous freezing. The parameterization is evaluated against a detailed numerical parcel model, and reproduces numerical simulations over a wide range of conditions with an average error of 6±33%. The parameterization also compares favorably against other formulations that require some form of numerical integration.

  7. XAFS studies of monodisperse Au nanoclusters formation in the etching process

    International Nuclear Information System (INIS)

    Yang, Lina; Huang, Ting; Liu, Wei; Bao, Jie; Huang, Yuanyuan; Cao, Yuanjie; Yao, Tao; Sun, Zhihu; Wei, Shiqiang

    2016-01-01

    Understanding the formation mechanism of gold nanoclusters is essential to the development of their synthetic chemistry. Here, by using x-ray absorption fine-structure (XAFS) spectroscopy, UV-Vis and MS spectra, the formation process of monodisperse Au 13 nanoclusters is investigated. We find that a critical step involving the formation of smaller Au 8 -Au 11 metastable intermediate clusters induced by the HCl + HSR etching of the polydisperse Au n precursor clusters occurs firstly. Then these intermediate species undergo a size-growth to Au 13 cores, followed by a slow structure rearrangement to reach the final stable structure. This work enriches the understanding of cluster formation chemistry and may guide the way towards the design and the controllable synthesis of nanoclusters. (paper)

  8. Straightforward and robust synthesis of monodisperse surface-functionalized gold nanoclusters

    Directory of Open Access Journals (Sweden)

    Silvia Varela-Aramburu

    2016-09-01

    Full Text Available Gold nanoclusters are small (1–3 nm nanoparticles with a high surface area that are useful for biomedical studies and drug delivery. The synthesis of small, surface-functionalized gold nanoclusters is greatly dependent on the reaction conditions. Here, we describe a straightforward, efficient and robust room temperature one-pot synthesis of 2 nm gold nanoclusters using thioglucose as a reducing and stabilizing agent, which was discovered by serendipity. The resultant monodisperse gold nanoclusters are more stable than those generated using some other common methods. The carboxylic acid contained in the stabilizing agent on the cluster surface serves as anchor for nanocluster functionalization. Alternatively, the addition of thiols serves to functionalize the nanoclusters. The resulting non-cytotoxic nanoclusters are taken up by cells and constitute a tuneable platform for biomedical applications including drug delivery.

  9. Experimental mixture design as a tool for the synthesis of antimicrobial selective molecularly imprinted monodisperse microbeads.

    Science.gov (United States)

    Benito-Peña, Elena; Navarro-Villoslada, Fernando; Carrasco, Sergio; Jockusch, Steffen; Ottaviani, M Francesca; Moreno-Bondi, Maria C

    2015-05-27

    The effect of the cross-linker on the shape and size of molecular imprinted polymer (MIP) beads prepared by precipitation polymerization has been evaluated using a chemometric approach. Molecularly imprinted microspheres for the selective recognition of fluoroquinolone antimicrobials were prepared in a one-step precipitation polymerization procedure using enrofloxacin (ENR) as the template molecule, methacrylic acid as functional monomer, 2-hydroxyethyl methacrylate as hydrophilic comonomer, and acetonitrile as the porogen. The type and amount of cross-linker, namely ethylene glycol dimethacrylate, divinylbenzene or trimethylolpropane trimethacrylate, to obtain monodispersed MIP spherical beads in the micrometer range was optimized using a simplex lattice design. Particle size and morphology were assessed by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption measurements. Electron paramagnetic resonance spectroscopy in conjunction with a nitroxide as spin probe revealed information about the microviscosity and polarity of the binding sites in imprinted and nonimprinted polymer beads.

  10. Photoelectrochemical performance of DSSC with monodisperse and polydisperse ZnO SPs

    Energy Technology Data Exchange (ETDEWEB)

    Wahyuono, Ruri Agung, E-mail: r-agung-w@ep.its.ac.id; Risanti, Doty D., E-mail: r-agung-w@ep.its.ac.id [Department of Engineering Physics, Institut Teknologi Sepuluh Nopember (Indonesia); Shirosaki, Tomohiro; Nagaoka, Shoji [Kumamoto Industrial Research Institute (Japan); Takafuji, Makoto; Ihara, Hirotaka [Department of Applied Chemistry and Biochemistry, Kumamoto University (Japan)

    2014-02-24

    Zinc oxide, ZnO, is one of oxide semiconductors being used in DSSC. ZnO is promising material for having fairly higher energy band gap and much higher bulk electron mobility than that of anatase TiO{sub 2}, the most widely used semiconductor for DSSC photoelectrode. This study introduces the synthesis of ZnO by precipitation method. The synthesis involves ZnAc dihydrate and diethylene glycol (DEG) for the chemicals. Various size of ZnO spherical particles (SPs) are obtained in polydisperse and monodisperse particles. Monolayer and bilayer DSSCs are fabricated in sandwich structure and sensitized with N719 dye for 3 and 5 hours. Monolayer DSSC using monodisperse particles (422 nm) is able to generate highest conversion efficiency of 0.569% (V{sub oc} = 541.3 mV, J{sub sc} = 1.92 mA/cm{sup 2}, and fill factor of 54.78%). Bilayer DSSC, i.e. combined 422 - 185 nm ZnO layer, can optimize the photocurrent action spectra in UV regime leading to high conversion efficiency of 0.568 (V{sub oc} = 568.2 mV, J{sub sc} = 2.22 mA/cm{sup 2}, and fill factor of 47.25%). The longer sensitizing time does not always produce better conversion efficiency since it can induce the dissolution of Zn atoms and formation of Zn{sup 2+} - dye resisting the electron transport from dye to ZnO photoelectrode.

  11. Highly sensitive glucose sensor based on monodisperse palladium nickel/activated carbon nanocomposites.

    Science.gov (United States)

    Koskun, Yağmur; Şavk, Aysun; Şen, Betül; Şen, Fatih

    2018-06-20

    Glucose enzyme biosensors have been used for a variety of applications such as medical diagnosis, bioprocess engineering, beverage industry and environmental scanning etc. and there is still a growing interest in glucose sensors. For this purpose, addressed herein, as a novel glucose sensor, highly sensitive activated carbon (AC) decorated monodisperse nickel and palladium alloy nanocomposites modified glassy carbon electrode (Ni-Pd@AC/GCE NCs) have been synthesized by in-situ reduction technique. Raman Spectroscopy (RS), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), cyclic voltammetry (CV) and chronoamperometry (CA) were used for the characterization of the prepared non-enzymatic glucose sensor. The characteristic sensor properties of the Ni-Pd@AC/GCE electrode were compared with Ni-Pd NCs/GCE, Ni@AC/GCE and Pd@AC/GCE and the results demonstrate that the AC is very effective in the enhancement of the electrocatalytic properties of sensor. In addition, the Ni-Pd@AC/GCE nanocomposites showed a very low detection limit of 0.014 μM, a wide linear range of 0.01 mM-1 mM and a very high sensitivity of 90 mA mM -1  cm -2 . Furthermore, the recommended sensor offer the various advantageous such as facile preparation, fast response time, high selectivity and sensitivity. Lastly, monodisperse Ni-Pd@AC/GCE was utilized to detect glucose in real sample species. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Production of monodispersed Oil-in Water Emulsion Using Crossflow-Type Silicon Microchannel Plate

    Energy Technology Data Exchange (ETDEWEB)

    Kawakatsu, Takahiro.; Komori, Hideaki.; Yonemoto, Toshikuni. [Tohoku University, Miyagi (Japan). Chemical Engineering Department; Nakajima, Mitsutoshi.; Kikuchi, Yuji. [National Food Research Institute, Ibaraki (Japan)

    1999-04-01

    A novel method for continuous productin of monodispersed oil-in-water (O/W) emulsion is developed using acrossflow-type silicaon microchannel plate. On the single crystal silicon plate, a liquid flow path for continuous phase was made, and at each side of th wall of the path an array of regular-sized slits was precisely fabricated. A flat glass plate was tightly attached on the microchannel plate to cover the top of the slits to form the array of microchannels. Regular-sized oil (triolein) droplets were generated by squeezing the oil through the microchannels into the continuous-phase water (0.3 wt% sodium lauryl sulfate solutin) flowing in the liquid path. Oil droplet size is significantly dependent on the microchannel structure, which is identified with the microchannel width, height, and the length of the terrace (a flat area at the microchannel outlet). Three types of microchannel plates having different microchannel structures generate monodispersed emulsions of different average droplet sizes, 16,20, and 48 {mu}m at the watr flow rate of 1.4x10{sup -2}mL{center_dot}min{sup -1}. For the microchannel plate which generates large droplets of 48 {mu}m, increasing the flow rate causes decreasing droplet size. However, for the microchannel plate which generates small droplets of 16 or 20 {mu}m, the size is not affected by the flow rate within the range from 1.4x10{sup -2}to 2.4 mL{center_dot}min{sup -1}. In every case, the droplet size distribution is narrow, and the geometric standard deviation is 1.03 or less. (author)

  13. Controlled synthesis of monodisperse gold nanorods with different aspect ratios in the presence of aromatic additives

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun; Wang, Feihu [Shanghai Jiao Tong University, School of Pharmacy (China); Guo, Yuan [University of Leeds, School of Chemistry and Astbury Centre for Structural Molecular Biology (United Kingdom); Chen, Rongjun, E-mail: rongjun.chen@imperial.ac.uk [Imperial College London, Department of Chemical Engineering (United Kingdom); Shen, Yuanyuan; Guo, Aijie; Liu, Jieying; Zhang, Xiao [Shanghai Jiao Tong University, School of Pharmacy (China); Zhou, Dejian, E-mail: d.zhou@leeds.ac.uk [University of Leeds, School of Chemistry and Astbury Centre for Structural Molecular Biology (United Kingdom); Guo, Shengrong, E-mail: srguo@sjtu.edu.cn [Shanghai Jiao Tong University, School of Pharmacy (China)

    2014-12-15

    This paper reports the synthesis of monodisperse gold nanorods (GNRs) via a simple seeded growth approach in the presence of different aromatic additives, such as 7-bromo-3-hydroxy-2-naphthoic acid (7-BrHNA), 3-hydroxy-2-naphthoic acid (HNA), 5-bromosalicylic acid (5-BrSA), salicylic acid (SA), or phenol (PhOH). Effects of the aromatic additives and hydrochloric acid (HCl) on the structure and optical properties of the synthesized GNRs were investigated. The longitudinal surface plasmon resonance (LSPR) peak wavelength of the resulting GNRs was found to be dependent on the aromatic additive in the following sequence: 5-BrSA (778 nm) > 7-BrHNA (706 nm) > SA (688 nm) > HNA (676 nm) > PhOH (638 nm) without the addition of HCl, but this was changed to 7-BrHNA (920 nm) > SA (890 nm) > HNA (872 nm) > PhOH (858 nm) > 5-BrSA (816 nm) or 7-BrHNA (1,005 nm) > PhOH (995 nm) > SA (990 nm) > HNA (980 nm) > 5-BrSA (815 nm) with the addition of HCl or HNO{sub 3}, respectively. The LSPR peak wavelength was increased with the increasing concentration of 7-BrHNA without HCl addition; however, there was a maximum LSPR peak wavelength when HCl was added. Interestingly, the LSPR peak wavelength was also increased with the amount of HCl added. The results presented here thus established a simple approach to synthesize monodisperse GNRs of different LSPR wavelengths.

  14. Nanoscale hotspots due to nonequilibrium thermal transport

    International Nuclear Information System (INIS)

    Sinha, Sanjiv; Goodson, Kenneth E.

    2004-01-01

    Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

  15. Superhydrophobic hybrid inorganic-organic thiol-ene surfaces fabricated via spray-deposition and photopolymerization.

    Science.gov (United States)

    Sparks, Bradley J; Hoff, Ethan F T; Xiong, Li; Goetz, James T; Patton, Derek L

    2013-03-13

    We report a simple and versatile method for the fabrication of superhydrophobic inorganic-organic thiol-ene coatings via sequential spray-deposition and photopolymerization under ambient conditions. The coatings are obtained by spray-deposition of UV-curable hybrid inorganic-organic thiol-ene resins consisting of pentaerythritol tetra(3-mercaptopropionate) (PETMP), triallyl isocyanurate (TTT), 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (TMTVSi), and hydrophobic fumed silica nanoparticles. The spray-deposition process and nanoparticle agglomeration/dispersion provide surfaces with hierarchical morphologies exhibiting both micro- and nanoscale roughness. The wetting behavior, dependent on the concentration of TMTVSi and hydrophobic silica nanoparticles, can be varied over a broad range to ultimately provide coatings with high static water contact angles (>150°), low contact angle hysteresis, and low roll off angles (spray-deposition and UV-cure process on a variety of substrate surfaces including glass, paper, stone, and cotton fabric.

  16. PREFACE: Nanoscale science and technology

    Science.gov (United States)

    Bellucci, Stefano

    2008-11-01

    , nanopowders) were discussed. Ab initio simulations on the atomic and electronic structure of single-walled BN nanotubes and nanoarches were illustrated by Yu F Zhukovskii. M B Muradov talked about nanoparticles of cadmium selenide and cadmium sulfide, which yield one of the perspective materials for application to solar cell elements, high-speed computing systems, catalyses and biomarkers in medicine. In the presentation, the process of transformation of nanoparticles cadmium of sulfide to nanoparticles of cadmium selenide by an ionic exchange from solutions of electrolytes was considered. The size of particles was controlled by the quantity of growth cycles. After manufacturing, the structures were investigated by atomic force microscope (AFM). Structures CdS:polymer transformed into CdSe:polymer with the help of ion-exchange. For the realization of the process of ionic exchange, solutions were prepared containing bivalent ions of selenium as follows: NaBH4 and Se in a weight parity 2:1 added in water 4NaBH4+2Se+7H2O→2NaHSe+Na2B4O7+14H2 In the prepared solution nanostructures CdS:polymer were immersed. Time of endurance was 2 h. After an ionic exchange the obtained structures were investigated by means of EDAX on a chemical composition. Results of analyses have shown that atoms of sulfur are completely replaced by selenium. The band gap of nanoparticles in comparison with initial samples is displaced in the long-wave area. It is connected with the fact that the width of the band gap of bulk crystals CdSe (1.74 eV) is smaller than the band gap of CdS (2.42 eV). Optical microscopy with spatial resolution beyond the diffraction limit obtained by using near field techniques was the subject of S Prato's talk. Scanning near field optical microscopy (SNOM) has developed into a powerful tool to investigate local optical properties that depend on heterogeneity of materials at nanoscale and to study nanoenvironment of biosystems. Crucial topics in SNOM are: force sensitivity and

  17. Insights into biogenic and chemical production of inorganic nanomaterials and nanostructures.

    Science.gov (United States)

    Faramarzi, Mohammad Ali; Sadighi, Armin

    2013-03-01

    The synthesis of inorganic nanomaterials and nanostructures by the means of diverse physical, chemical, and biological principles has been developed in recent decades. The nanoscale materials and structures creation continue to be an active area of researches due to the exciting properties of the resulting nanomaterials and their innovative applications. Despite physical and chemical approaches which have been used for a long time to produce nanomaterials, biological resources as green candidates that can replace old production methods have been focused in recent years to generate various inorganic nanoparticles (NPs) or other nanoscale structures. Cost-effective, eco-friendly, energy efficient, and nontoxic produced nanomaterials using diverse biological entities have been received increasing attention in the last two decades in contrast to physical and chemical methods owe using toxic solvents, generate unwanted by-products, and high energy consumption which restrict the popularity of these ways employed in nanometric science and engineering. In this review, the biosynthesis of gold, silver, gold-silver alloy, magnetic, semiconductor nanocrystals, silica, zirconia, titania, palladium, bismuth, selenium, antimony sulfide, and platinum NPs, using bacteria, actinomycetes, fungi, yeasts, plant extracts and also informational bio-macromolecules including proteins, polypeptides, DNA, and RNA have been reported extensively to mention the current status of the biological inorganic nanomaterial production. In other hand, two well-known wet chemical techniques, namely chemical reduction and sol-gel methods, used to produce various types of nanocrystalline powders, metal oxides, and hybrid organic-inorganic nanomaterials have presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Nanoscale Coloristic Pigments: Upper Limits on Releases from Pigmented Plastic during Environmental Aging, In Food Contact, and by Leaching

    DEFF Research Database (Denmark)

    Neubauer, Nicole; Scifo, Lorette; Navratilova, Jana

    2017-01-01

    The life cycle of nanoscale pigments in plastics may cause environmental or human exposure by various release scenarios. We investigated spontaneous and induced release with mechanical stress during/after simulated sunlight and rain degradation of polyethylene (PE) with organic and inorganic pigm...... investigated scenarios, with upper limits of 10 mg/m2 or 1600 particles/mL. This is the first holistic confirmation that pigment nanomaterials remain strongly contained in a plastic that has low diffusion and high persistence such as the polyolefin High Density Polyethylene (HDPE)....

  19. Inorganic, coordination and organometallic compounds

    International Nuclear Information System (INIS)

    Jursik, F.

    1978-01-01

    Separation of cations and anions of inorganic, coordination and metalloorganic compounds by the method of liquid column chromatography is considered. Common scheme of multicomponent cation mixture is suggesteed. Separation conditions, adsrbents, eluents, pH value solution concenstration, elution rate are also suggested. Separation of rare earth elements Cs, Be, Cd, Te, Th, U, Mo, Re, V, Ru, Zr, In compounds is considered as an example of liquid column chromatography application. Data on column chromatography application are summarized in a table

  20. General and Robust Strategies for Multifunctional Organic-Inorganic Nanocompositesvia Direct Growth of Monodisperse Nanocrystals Intimately and Permanently Connected with Polymers

    Science.gov (United States)

    2016-04-21

    cells: from complex nanostructure to planar heterojunction ”, Journal of Materials Chemistry A, 2, 5994 (2014). (featured on Cover of Journal of...naphthalenide solution. Trifluoroacetic acid (TFA, 99%), Yttrium(III) oxide (Y2O3, 99.99%), Ytterbium(III) oxide (Yb2O3, 99.9%), Erbium(III) oxide ...Er2O3, ≥99.99%) and Thulium(III) oxide (Tm2O3, 99.9%) were purchased from Sigma-Aldrich and used as received. Gold(III) chloride trihydrate (HAuCl4·3H2O

  1. Metal Fe3+ ions assisted synthesis of highly monodisperse Ag/SiO2 nanohybrids and their antibacterial activity

    International Nuclear Information System (INIS)

    Zhang, Nianchun; Xue, Feng; Yu, Xiang; Zhou, Huihua; Ding, Enyong

    2013-01-01

    Graphical abstract: TEM images of the Ag/SiO 2 -2 nanohybrids. The homogeneous and more mono-disperse Ag nanoparticles deposit on SiO 2 spheres. Through this method, Ag nanoparticles are easily formed on the surface of SiO 2 compared to other methods. Highlights: ► We prepared homogeneous and mono-dispersed Ag/SiO 2 -2 nanohybrids by adding Fe 3+ ions. ► The Ag/SiO 2 -2 nanohybrids had core(SiO 2 )-shell(Ag) structure. ► The Ag/SiO 2 -2 nanohybrids exhibited excellent antibacterial activity against bacteria. ► The reaction temperature was lower and the yield of Ag/SiO 2 -2 nanohybrids were higher. - Abstract: Highly monodispersed Ag/SiO 2 nanohybrids with excellent antibacterial property were synthesized by using DMF as a reducing agent and employing an additional redox potential of metal Fe 3+ ion as a catalytic agent. The obtained Ag/SiO 2 -2 nanohybrids of about 240 nm were highly monodispersity and uniformity by adding trace Fe 3+ ions into the reaction which Ag + reacted with N,N-dimethyl formamide (DMF) at 70 °C. Compared to the conventional techniques, which need long time and high temperature for silica coating of Ag nanoparticles, this new method was capable of synthesizing monodispersed, uniform, high yield Ag/SiO 2 nanohybrids. The electron was transferred from the Fe 2+ ion to the Ag + ion to accelerate the nucleation of silver nanoparticles. The chemical structures, morphologies and properties of the Ag/SiO 2 nanohybrids were characterized by X-ray diffraction (XRD), (High-resolution, Scanning transmission) transmission electron microscopy (TEM, HRTEM and STEM), and X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy (UV–vis) and test of antibacterial. The results demonstrated that the silver nanoparticles supported on the surface of SiO 2 spheres in Ag/SiO 2 -2 nanohybrids structure, the Ag nanoparticles were homogeneous and monodispersed. The results also indicated that the Ag/SiO 2 -2 nanohybrid had excellent antibacterial.

  2. Nanoscale microstructural characterization of a nanobainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Timokhina, I.B., E-mail: ilana.timokhina@eng.monash.edu.au [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia); Beladi, H. [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia); Xiong, X.Y. [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Adachi, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Hodgson, P.D. [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia)

    2011-08-15

    A 0.79 C-1.5 Si-1.98 Mn-0.98 Cr-0.24 Mo-1.06 Al-1.58 Co (wt.%) steel was isothermally heat treated at 200 deg. C for 10 days and 350 deg. C for 1 day to form a nanoscale bainitic microstructure consisting of nanobainitic ferrite laths with high dislocation density and retained austenite films. The microstructures of the samples were characterized by transmission electron microscopy and atom probe tomography. Despite the formation of nanoscale bainite with a high volume fraction of retained austenite in both steels, the ductility of both steels was surprisingly low. It is believed that this was associated with the formation of carbon-depleted retained austenite after isothermal transformation at 200 deg. C due to the formation of high number of Fe-C clusters and particles in the bainitic ferrite laths and carbon-enriched austenite after isothermal transformation at 350 deg. C.

  3. Bulk nanoscale materials in steel products

    International Nuclear Information System (INIS)

    Chehab, B; Wang, X; Masse, J-P; Zurob, H; Embury, D; Bouaziz, O

    2010-01-01

    Although a number of nanoscale metallic materials exhibit interesting mechanical properties the fabrication paths are often complex and difficult to apply to bulk structural materials. However a number of steels which exhibit combinations of plasticity and phase transitions can be deformed to produce ultra high strength levels in the range 1 to 3 GPa. The resultant high stored energy and complex microstructures allow new nanoscale structures to be produced by combinations of recovery and recrystallisation. The resultant structures exhibit totally new combinations of strength and ductility to be achieved. In specific cases this also enables both the nature of the grain boundary structure and the spatial variation in structure to be controlled. In this presentation both the detailed microstructural features and their relation to the strength, work-hardening capacity and ductility will be discussed for a number of martensitic and austenitic steels.

  4. Hybrid, Nanoscale Phospholipid/Block Copolymer Vesicles

    Directory of Open Access Journals (Sweden)

    Bo Liedberg

    2013-09-01

    Full Text Available Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles (GUVs via electroformation. Here, we are interested in exploring the self-assembly and properties of the analogous nanoscale hybrid vesicles (ca. 100 nm in diameter of the same composition prepared by film-hydration and extrusion. We show that the self-assembly and content-release behavior of nanoscale polybutadiene-b-poly(ethylene oxide (PB-PEO/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC hybrid phospholipid/block copolymer vesicles can be tuned by the mixing ratio of the amphiphiles. In brief, these hybrids may provide alternative tools for drug delivery purposes and molecular imaging/sensing applications and clearly open up new avenues for further investigation.

  5. Scanning nanoscale multiprobes for conductivity measurements

    DEFF Research Database (Denmark)

    Bøggild, Peter; Hansen, Torben Mikael; Kuhn, Oliver

    2000-01-01

    We report fabrication and measurements with two- and four-point probes with nanoscale dimensions, for high spatial resolution conductivity measurements on surfaces and thin films. By combination of conventional microfabrication and additive three-dimensional nanolithography, we have obtained...... electrode spacings down to 200 nm. At the tips of four silicon oxide microcantilevers, narrow carbon tips are grown in converging directions and subsequently coated with a conducting layer. The probe is placed in contact with a conducting surface, whereby the electrode resistance can be determined....... The nanoelectrodes withstand considerable contact force before breaking. The probe offers a unique possibility to position the voltage sensors, as well as the source and drain electrodes in areas of nanoscale dimensions. ©2000 American Institute of Physics....

  6. Infochemistry Information Processing at the Nanoscale

    CERN Document Server

    Szacilowski, Konrad

    2012-01-01

    Infochemistry: Information Processing at the Nanoscale, defines a new field of science, and describes the processes, systems and devices at the interface between chemistry and information sciences. The book is devoted to the application of molecular species and nanostructures to advanced information processing. It includes the design and synthesis of suitable materials and nanostructures, their characterization, and finally applications of molecular species and nanostructures for information storage and processing purposes. Divided into twelve chapters; the first three chapters serve as an int

  7. Fourth International Conference on Nanoscale Magnetism

    CERN Document Server

    Aktas, Bekir; Advances in Nanoscale Magnetism

    2009-01-01

    The book aims to provide an overview of recent progress in the understanding of magnetic properties in nanoscale through recent results of various theoretical and experimental investigations. The papers describe a wide range of physical aspects, together with theoretical and experimental methods. It is of central interest to researchers and specialists in magnetism and magnetic materials science, both in academic and industrial research, as well as advanced students.

  8. DOE - BES Nanoscale Science Research Centers (NSRCs)

    Energy Technology Data Exchange (ETDEWEB)

    Beecher, Cathy Jo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-14

    These are slides from a powerpoint shown to guests during tours of Center for Integrated Nanotechnologies (CINT) at Los Alamos National Laboratory. It shows the five DOE-BES nanoscale science research centers (NSRCs), which are located at different national laboratories throughout the country. Then it goes into detail specifically about the Center for Integrated Nanotechnologies at LANL, including statistics on its user community and CINT's New Mexico industrial users.

  9. Nanoscale Science, Engineering and Technology Research Directions

    Energy Technology Data Exchange (ETDEWEB)

    Lowndes, D. H.; Alivisatos, A. P.; Alper, M.; Averback, R. S.; Jacob Barhen, J.; Eastman, J. A.; Imre, D.; Lowndes, D. H.; McNulty, I.; Michalske, T. A.; Ho, K-M; Nozik, A. J.; Russell, T. P.; Valentin, R. A.; Welch, D. O.; Barhen, J.; Agnew, S. R.; Bellon, P.; Blair, J.; Boatner, L. A.; Braiman, Y.; Budai, J. D.; Crabtree, G. W.; Feldman, L. C.; Flynn, C. P.; Geohegan, D. B.; George, E. P.; Greenbaum, E.; Grigoropoulos, C.; Haynes, T. E.; Heberlein, J.; Hichman, J.; Holland, O. W.; Honda, S.; Horton, J. A.; Hu, M. Z.-C.; Jesson, D. E.; Joy, D. C.; Krauss, A.; Kwok, W.-K.; Larson, B. C.; Larson, D. J.; Likharev, K.; Liu, C. T.; Majumdar, A.; Maziasz, P. J.; Meldrum, A.; Miller, J. C.; Modine, F. A.; Pennycook, S. J.; Pharr, G. M.; Phillpot, S.; Price, D. L.; Protopopescu, V.; Poker, D. B.; Pui, D.; Ramsey, J. M.; Rao, N.; Reichl, L.; Roberto, J.; Saboungi, M-L; Simpson, M.; Strieffer, S.; Thundat, T.; Wambsganss, M.; Wendleken, J.; White, C. W.; Wilemski, G.; Withrow, S. P.; Wolf, D.; Zhu, J. H.; Zuhr, R. A.; Zunger, A.; Lowe, S.

    1999-01-01

    This report describes important future research directions in nanoscale science, engineering and technology. It was prepared in connection with an anticipated national research initiative on nanotechnology for the twenty-first century. The research directions described are not expected to be inclusive but illustrate the wide range of research opportunities and challenges that could be undertaken through the national laboratories and their major national scientific user facilities with the support of universities and industry.

  10. Nanoscale-Agglomerate-Mediated Heterogeneous Nucleation.

    Science.gov (United States)

    Cha, Hyeongyun; Wu, Alex; Kim, Moon-Kyung; Saigusa, Kosuke; Liu, Aihua; Miljkovic, Nenad

    2017-12-13

    Water vapor condensation on hydrophobic surfaces has received much attention due to its ability to rapidly shed water droplets and enhance heat transfer, anti-icing, water harvesting, energy harvesting, and self-cleaning performance. However, the mechanism of heterogeneous nucleation on hydrophobic surfaces remains poorly understood and is attributed to defects in the hydrophobic coating exposing the high surface energy substrate. Here, we observe the formation of high surface energy nanoscale agglomerates on hydrophobic coatings after condensation/evaporation cycles in ambient conditions. To investigate the deposition dynamics, we studied the nanoscale agglomerates as a function of condensation/evaporation cycles via optical and field emission scanning electron microscopy (FESEM), microgoniometric contact angle measurements, nucleation statistics, and energy dispersive X-ray spectroscopy (EDS). The FESEM and EDS results indicated that the nanoscale agglomerates stem from absorption of sulfuric acid based aerosol particles inside the droplet and adsorption of volatile organic compounds such as methanethiol (CH 3 SH), dimethyl disulfide (CH 3 SSCH), and dimethyl trisulfide (CH 3 SSSCH 3 ) on the liquid-vapor interface during water vapor condensation, which act as preferential sites for heterogeneous nucleation after evaporation. The insights gained from this study elucidate fundamental aspects governing the behavior of both short- and long-term heterogeneous nucleation on hydrophobic surfaces, suggest previously unexplored microfabrication and air purification techniques, and present insights into the challenges facing the development of durable dropwise condensing surfaces.

  11. Nanoscale piezoelectric vibration energy harvester design

    Science.gov (United States)

    Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin

    2017-09-01

    Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs) can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton's principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  12. Static electric field enhancement in nanoscale structures

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, Bruno, E-mail: bruno.lepetit@irsamc.ups-tlse.fr; Lemoine, Didier, E-mail: didier.lemoine@irsamc.ups-tlse.fr [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse (France); CNRS, UMR 5589, F-31062 Toulouse (France); Márquez-Mijares, Maykel, E-mail: mmarquez@instec.cu [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse (France); CNRS, UMR 5589, F-31062 Toulouse (France); Instituto Superior de Tecnologías y Ciencias Aplicadas, Avenida Salvador Allende 1110, Quinta de los Molinos, La Habana (Cuba)

    2016-08-28

    We study the effect of local atomic- and nano-scale protrusions on field emission and, in particular, on the local field enhancement which plays a key role as known from the Fowler-Nordheim model of electronic emission. We study atomic size defects which consist of right angle steps forming an infinite length staircase on a tungsten surface. This structure is embedded in a 1 GV/m ambient electrostatic field. We perform calculations based upon density functional theory in order to characterize the total and induced electronic densities as well as the local electrostatic fields taking into account the detailed atomic structure of the metal. We show how the results must be processed to become comparable with those of a simple homogeneous tungsten sheet electrostatic model. We also describe an innovative procedure to extrapolate our results to nanoscale defects of larger sizes, which relies on the microscopic findings to guide, tune, and improve the homogeneous metal model, thus gaining predictive power. Furthermore, we evidence analytical power laws for the field enhancement characterization. The main physics-wise outcome of this analysis is that limited field enhancement is to be expected from atomic- and nano-scale defects.

  13. Tribological characteristics of monodispersed cerium borate nanospheres in biodegradable rapeseed oil lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Boshui, Chen, E-mail: boshuichen@163.com; Kecheng, Gu; Jianhua, Fang; Jiang, Wu; Jiu, Wang; Nan, Zhang

    2015-10-30

    Graphical abstract: - Highlights: • Monodispersed stearic acid-capped cerium borate composite nanoparticles were prepared by hydrothermal method. Their morphologies, element compositions, size distributions, crystal and chemical structures, hydrophobic characteristics were also characterized. • The surface-capped cerium borate nanoparticles exhibited excellent dispersing stability in rapeseed oil. As new lubricating additives, they were also outstanding in enhancing friction-reducing and anti-wear capacities of rapeseed oil in biodegradable rapeseed oil. The results presented in this paper would be of important significance for developing green lubricants and lubricant additives. • The prominent tribological performances of SA/CeBO{sub 3} in rapeseed oil were investigated and attributed to the formation of a composite boundary lubrication film mainly composed of lubricous tribochemical species on the tribo-surfaces. - Abstract: Stearic acid-capped cerium borate composite nanoparticles, abbreviated as SA/CeBO{sub 3}, were prepared by hydrothermal method. The morphologies, element compositions, size distributions, crystal and chemical structures, hydrophobic characteristics, of SA/CeBO{sub 3} were characterized by scanning electron microscope, energy dispersive X-ray spectrometer, dynamic laser particle size analyzer, X-ray diffraction, and Fourier transform infrared spectrometer, respectively. The friction and wear performances of SA/CeBO{sub 3} as a lubricating additive in a rapeseed oil were evaluated on a four-ball tribo-tester. The tribochemical characteristics of the worn surfaces were investigated by X-ray photoelectron spectroscopy. The results showed that the hydrophobic SA/CeBO{sub 3} were monodispersed nanospheres with an average diameter of 8 nm, and exhibited excellent dispersing stability in rapeseed oil. Meanwhile, SA/CeBO{sub 3} nanospheres were outstanding in enhancing friction-reducing and anti-wear capacities of rapeseed oil. The prominent

  14. Synthesis and optoelectronic properties of a monodispersed macrocycle oligomer consisting of three triarylamine units

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Qinggang, E-mail: gangq0172@163.com [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, College of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Pukou District, Nanjing 210044 (China); Qian, Haiyan, E-mail: qianhaiy@163.com [College of Material Science and Technology, Nanjing University of Technology, 5 Xinmofan Road, Nanjing 210009 (China); Zhou, Yonghui; Li, Jun; Xiao, Huining [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, College of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Pukou District, Nanjing 210044 (China)

    2012-08-15

    A monodispersed macrocyclic oligomer constructed by three triarylmine units ((TPAT){sub 3}) was designed and readily synthesized from the monomer of 3-(4 Prime -(phenyl(4 Double-Prime -methylphenyl)amino)-phenyl)pentan-3-ol (TPAT) by means of a simple Friedel-Crafts alkylation reaction. The structure of the resultant macrocycle was examined using FT-IR, NMR and MALDI-TOF mass spectroscopy. Compared with 1,10-bis(di-4-tolylaminophenyl) cyclohexane (TAPC) and tri-p-tolylamine (TTA), (TPAT){sub 3} possesses the three-dimensional chair conformation and the higher T{sub g}. In the photoluminescence (PL) spectrum of (TPAT){sub 3} film, there are no excimer emission peaks in the range of 400-550 nm region as those of TAPC and TTA. Besides an EL peak at 386 nm, the single-layer device occured only the 438 nm excimer emission peak, whose intensity increased with the excitation voltage increase. Using 1,3,5-Tris(N-phenylbenzimidazol-2-yl)-benzene (TPBI) as the electron-transporting layer, the resulting double-layer device ITO/(TPAT){sub 3} (40 nm)/TPBI (40 nm)/Mg:Ag (10:1; 50 nm)/Ag (100 nm) only exhibited a 438 nm maximum symmetrical emission peak under an excitation voltage of 14 V. However, as the applied voltage was increased from 14 V to 19 V, the intensity of the symmetrical curve with a 468 nm peak from exciplex emission gets stronger and stronger. In fact, the resultant emission curve was asymmetrical, due to the overlap of two symmetrical curves with 438 nm and 468 nm peaks, respectively. The maximum luminance and luminous efficiency are 2240 cd m{sup -2} at 18.8 V and 1.73 cd A{sup -1} at 1878 cd m{sup -2} (13.9 V). Highlights: Black-Right-Pointing-Pointer The monodispersed macrocyclic oligomer constructed by three triarylamine units was synthesized and characterized. Black-Right-Pointing-Pointer The PL of (TPAT){sub 3} film does not emerge TAPC and TTA's emission peaks of over 400 nm region. Black-Right-Pointing-Pointer The 438 nm emission peak was found from

  15. Preparation and characterization of monodisperse large-porous silica microspheres as the matrix for protein separation.

    Science.gov (United States)

    Xia, Hongjun; Wan, Guangping; Zhao, Junlong; Liu, Jiawei; Bai, Quan

    2016-11-04

    High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (P GMA-EDMA ) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species. Then the low molecular weight species diffused into the functionalized P GMA-EDMA microspheres by induction force of the amino groups to form polymer/silica hybrid microspheres. Finally, the organic polymer templates were removed by calcination, and the large-porous silica microspheres were obtained. The compositions, morphology, size distribution, specific surface area and pore size distribution of the porous silica microspheres were characterized by infrared analyzer, scanning-electron microscopy, dynamic laser scattering, the mercury intrusion method and thermal gravimetric analysis, respectively. The results show that the agglomeration of the hybrid microspheres can be overcome when the templates were functionalized with TEPA as amination reagent, and the yield of 95.7% of the monodisperse large-porous silica microspheres can be achieved with high concentration of polymer templates. The resulting large-porous silica microspheres were modified with octadecyltrichlorosilane (ODS) and the chromatographic evaluation was performed by separating the proteins and the digest of BSA. The baseline separation of seven kinds of protein standards was achieved, and the column delivered a better performance when separating BSA digests

  16. Generation and stabilization of whey-based monodisperse naoemulsions using ultra-high pressure homogenization and small amphipathic co-emulsifier combinations

    Science.gov (United States)

    Ultra-high-pressure homogenization (UHPH) was used to generate monodisperse stable peanut oil nanoemulsions within a desired nanosize range (whey protein concentrate (WPC), sodium dodecyl sulfate, Triton X-100 (X100), and zwitterionic sulfobetaine-base...

  17. Thermal modelling of normal distributed nanoparticles through thickness in an inorganic material matrix

    Science.gov (United States)

    Latré, S.; Desplentere, F.; De Pooter, S.; Seveno, D.

    2017-10-01

    Nanoscale materials showing superior thermal properties have raised the interest of the building industry. By adding these materials to conventional construction materials, it is possible to decrease the total thermal conductivity by almost one order of magnitude. This conductivity is mainly influenced by the dispersion quality within the matrix material. At the industrial scale, the main challenge is to control this dispersion to reduce or even eliminate thermal bridges. This allows to reach an industrially relevant process to balance out the high material cost and their superior thermal insulation properties. Therefore, a methodology is required to measure and describe these nanoscale distributions within the inorganic matrix material. These distributions are either random or normally distributed through thickness within the matrix material. We show that the influence of these distributions is meaningful and modifies the thermal conductivity of the building material. Hence, this strategy will generate a thermal model allowing to predict the thermal behavior of the nanoscale particles and their distributions. This thermal model will be validated by the hot wire technique. For the moment, a good correlation is found between the numerical results and experimental data for a randomly distributed form of nanoparticles in all directions.

  18. Monodisperse gold-palladium alloy nanoparticles and their composition-controlled catalysis in formic acid dehydrogenation under mild conditions.

    Science.gov (United States)

    Metin, Önder; Sun, Xiaolian; Sun, Shouheng

    2013-02-07

    Monodisperse 4 nm AuPd alloy nanoparticles with controlled composition were synthesized by co-reduction of hydrogen tetrachloroaurate(III) hydrate and palladium(II) acetylacetonate with a borane-morpholine complex in oleylamine. These NPs showed high activity (TOF = 230 h(-1)) and stability in catalyzing formic acid dehydrogenation and hydrogen production in water at 50 °C without any additives.

  19. Generation of monodisperse cell-sized microdroplets using a centrifuge-based axisymmetric co-flowing microfluidic device.

    Science.gov (United States)

    Yamashita, Hitoyoshi; Morita, Masamune; Sugiura, Haruka; Fujiwara, Kei; Onoe, Hiroaki; Takinoue, Masahiro

    2015-04-01

    We report an easy-to-use generation method of biologically compatible monodisperse water-in-oil microdroplets using a glass-capillary-based microfluidic device in a tabletop mini-centrifuge. This device does not require complicated microfabrication; furthermore, only a small sample volume is required in experiments. Therefore, we believe that this method will assist biochemical and cell-biological experiments. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  20. Nomenclature on an inorganic compound

    International Nuclear Information System (INIS)

    1998-10-01

    This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

  1. Facile Synthesis of Monodispersed Polysulfide Spheres for Building Structural Colors with High Color Visibility and Broad Viewing Angle.

    Science.gov (United States)

    Li, Feihu; Tang, Bingtao; Wu, Suli; Zhang, Shufen

    2017-01-01

    The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light-absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3-trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large-scale and high-quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Nonlinear Stress Relaxation of ``Quasi-monodisperse'' Miscible Blends of cis-Polyisoprene and Poly(ptert-butylstyrene)

    Science.gov (United States)

    Watanabe, Hiroshi; Matsumiya, Yumi

    Viscoelastic relaxation was examined for entangled miscible blends of cis-polyisoprene (PI) and poly(ptert-butylstyrene) (PtBS). The terminal relaxation times of PI and PtBS therein, τPI and τPtBS, changed with the composition wPI and the molecular weights MPI and MPtBS. This ratio became unity when the wPI, MPI, and MPtBS values were chosen adequately. For example, in a blend with wPI = 0.75, MPI = 321k, and MPtBS = 91k at T = 40ûC, τPI/τPtBS = 1 and M/Me = 55 and 8.3 for PI and PtBS. Under small strains, this blend exhibited sharp, single-step terminal relaxation as similar to monodisperse homopolymers, thereby behaving as a ``quasi-monodisperse'' material. Under large step strains, the blend exhibited moderate nonlinear damping known as the type-A damping for entangled monodisperse homopolymers. Nevertheless, PI had M/Me = 55 in that blend, and homopolymers having such a large M/Me ratio exhibit very strong type-C damping. Thus, as compared to homopolymers, the nonlinearity was suppressed in the PI/PtBS blend having the large M/Me ratio. This suppression is discussed in relation to the slow Rouse retraction of the coexisting PtBS chains (having M/Me = 8.3 in the blend).

  3. Production of monodisperse respirable aerosols of 241AmO2 and evaluation of in vitro dissolution

    International Nuclear Information System (INIS)

    Boyd, H.A.; Raabe, O.G.; Peterson, P.K.

    1974-01-01

    A method is described for production of monodisperse (sigma//sub g/ less than 1.2) particles of 241 AmO 2 for use in inhalation experiments with dogs and rodents. The effects of physical and chemical factors on the production of polydisperse aerosols of 241 AmO 2 were studied and evaluated. The best aerosol was achieved when a suspension of americium hydroxide with 2.5 mg Am/ml at pH = 7.3 was aerosolized and passed through two heating columns in succession, the first at 300 0 C and the second at 1050 0 C. The particles were roughly spherical and had densities near 8 gm/cm 3 ; the aerosol AMAD and sigma/sub g/ were about 1.5 μm and 1.7, respectively. Monodisperse particles were separated and collected with the Lovelace Aerosol Particle Separator (LAPS) and subsequently suspended in deionized water with pH adjusted to 10.2 with NH 3 for nebulization to produce monodisperse aerosols for inhalation exposures. Particles collected on filters during inhalation experiments were used for evaluation of in vitro dissolution rates with two systems and various forms of a lung fluid simulant. The important role of phosphate ions in such dissolution systems was demonstrated, suggesting the potential for the equally important role of free phosphate in retarding dissolution of AmO 2 particles in the lung. (U.S.)

  4. Synthesis, characterization and magnetic properties of highly monodispersed PtNi nanoparticles

    International Nuclear Information System (INIS)

    Du, Juan-Juan; Yang, Yi; Zhang, Rong-Hua; Zhou, Xin-Wen

    2015-01-01

    In this paper, we report the controlled-synthesis of PtNi nanoparticles through galvanic displacement reaction and chemical reduction. The size, composition and morphology of the products are characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), energy dispersed X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses. The structure and composition of the PtNi nanoparticles can be controlled by adjusting the synthetic conditions. The possible formation mechanism is obtained from the academic analysis and experimental studies. The results of the magnetic measurement illustrate that the PtNi nanoparticles show a superparamagnetic behavior with a blocking temperature (T B ) about 8.0 K. - Highlights: • Highly monodispersed PtNi nanoparticles were synthesized by galvanic displacement reaction. • The formation of Pt nanocrystals was the foremost step because of its self-catalysis effect. • The PtNi nanoparticles show a superparamagnetic behavior with a T B about 8.0 K

  5. Production and characterization of monodisperse uranium particles for nuclear safeguards applications

    Energy Technology Data Exchange (ETDEWEB)

    Knott, Alexander

    2016-07-01

    Environmental sampling is a very effective measure to detect undeclared nuclear activities. Generally, samples are taken as swipe samples on cotton. These swipes contain minute quantities of particulates which have an inherent signature of their production and release scenario. These inspection samples are assessed for their morphology, elemental composition and their isotopic vectors. Mass spectrometry plays a crucial role in determining the isotopic ratios of uranium. Method validation and instrument calibration with well-characterized quality control (QC)-materials, reference materials (RMs) and certified reference materials (CRMs) ensures reliable data output. Currently, the availability of suitable well defined microparticles containing uranium and plutonium reference materials is very limited. Primarily, metals, oxides and various uranium and plutonium containing solutions are commercially available. Therefore, the IAEA's Safeguards Analytical Services (SGAS) cooperates with the Institute of Nuclear Waste Management and Reactor Safety (IEK-6) at the Forschungszentrum Juelich GmbH in a joint task entitled ''Production of Particle Reference Materials''. The work presented in this thesis has been partially funded by the IAEA, Forschungszentrum Juelich GmbH and the Federal Ministry of Economic Affairs and Energy (BMWi) through the ''Joint Program on the Technical Development and Further Improvement of IAEA Safeguards between the Government of the Federal Republic of Germany and the IAEA''. The first step towards monodisperse microparticles was the development of pure uranium oxide particles made from certified reference materials. The focus of the dissertation is (1) the implementation of a working setup to produce monodisperse uranium oxide particles and (2) the characterization of these particles towards the application as QC-material. Monodisperse uranium oxide particles were produced by spray pyrolysis. It was

  6. A new method for preparing mono-dispersed nanoparticles using magnetized water

    Science.gov (United States)

    Nakhaei Pour, Ali; Gholizadeh, Mostafa; Housaindokht, Mohammadreza; Moosavi, Fatemeh; Monhemi, Hasan

    2017-04-01

    We studied the use of magnetized water on the size of the nanoparticles. Magnetized water found to reduce the diameter of the nanoparticles during a homogeneous precipitation process, which is a combination of nucleation and nuclei growth processes. We found that the modified water, which demonstrated different physical properties especially on the surface tension and viscosity, significantly influenced the both processes. Therefore, the nucleation process was initially prolonged in the homogeneous precipitation process due to the lower critical size of nucleus and higher rate of nucleation, and consequently formed smaller particles and a larger number of particles. Furthermore, the growth rate of nanoparticles was hindered owing to the higher viscosity of the water and restriction in the mass transport process. As a result, the precipitated particles with the magnetized water were eventually structured smaller particle diameter compared to the bulk. The presented method in here indicated a low cost, straightforward, and feasible technique for industrial application. In addition, this method could open a new promising perspective on nanomaterial synthesis in order to facilitate the production of monodispersed nanoparticles. Molecular dynamic confirmed that surface tension decreased as the external magnetic field was applied. Moreover, the density profile illustrated that the average number of hydrogen atoms is greater than oxygen atoms.

  7. Synthesis of Monodisperse Nanocrystals via Microreaction: Open-to-Air Synthesis with Oleylamine as a Coligand

    Directory of Open Access Journals (Sweden)

    Yang Hongwei

    2009-01-01

    Full Text Available Abstract Microreaction provides a controllable tool to synthesize CdSe nanocrystals (NCs in an accelerated fashion. However, the surface traps created during the fast growth usually result in low photoluminescence (PL efficiency for the formed products. Herein, the reproducible synthesis of highly luminescent CdSe NCs directly in open air was reported, with a microreactor as the controllable reaction tool. Spectra investigation elucidated that applying OLA both in Se and Cd stock solutions could advantageously promote the diffusion between the two precursors, resulting in narrow full-width-at-half maximum (FWHM of PL (26 nm. Meanwhile, the addition of OLA in the source solution was demonstrated helpful to improve the reactivity of Cd monomer. In this case, the focus of size distribution was accomplished during the early reaction stage. Furthermore, if the volume percentage (vol.% of OLA in the precursors exceeded a threshold of 37.5%, the resulted CdSe NCs demonstrated long-term fixing of size distribution up to 300 s. The observed phenomena facilitated the preparation of a size series of monodisperse CdSe NCs merely by the variation of residence time. With the volume percentage of OLA as 37.5% in the source solution, a 78 nm tuning of PL spectra (from 507 to 585 was obtained through the variation of residence time from 2 s to 160 s, while maintaining narrow FMWH of PL (26–31 nm and high QY of PL (35–55%.

  8. Magnetically Triggered Monodispersed Nanocomposite Fabricated by Microfluidic Approach for Drug Delivery

    KAUST Repository

    Yassine, Omar; Li, Erqiang; Alfadhel, Ahmed; Zaher, A.; Kavaldzhiev, Mincho; Thoroddsen, Sigurdur T; Kosel, Jü rgen

    2016-01-01

    Responsive microgel poly(N-isopropylacrylamide) or PNIPAM is a gel that can swell or shrink in response to external stimuli (temperature, pH, etc.). In this work, a nanocomposite gel is developed consisting of PNIPAM and magnetic iron oxide nanobeads for controlled release of liquids (like drugs) upon exposure to an alternating magnetic field. Microparticles of the nanocomposite are fabricated efficiently with a monodisperse size distribution and a diameter ranging from 20 to 500  µ m at a rate of up to 1 kHz using a simple and inexpensive microfluidic system. The nanocomposite is heated through magnetic losses, which is exploited for a remotely stimulated liquid release. The efficiency of the microparticles for controlled drug release applications is tested with a solution of Rhodamine B as a liquid drug model. In continuous and pulsatile mode, a release of 7% and 80% was achieved, respectively. Compared to external thermal actuation that heats the entire surrounding or embedded heaters that need complex fabrication steps, the magnetic actuation provides localized heating and is easy to implement with our microfluidic fabrication method.

  9. Growth of monodisperse nanocrystals of cerium oxide during synthesis and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Swapankumar, E-mail: swapankumar.ghosh2@mail.dcu.ie; Divya, Damodaran [National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR) (India); Remani, Kottayilpadi C. [Sree Neelakanda Government Sanskrit College, Department of Chemistry (India); Sreeremya, Thadathil S. [National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR) (India)

    2010-06-15

    Monodisperse cerium oxide nanocrystals have been successfully synthesised using simple ammonia precipitation technique from cerium(III) nitrate solution at different temperatures in the range 35-80 {sup o}C. The activation energy for growth of CeO{sub 2} nanocrystals during the precipitation is calculated as 11.54 kJ/mol using Arrhenius plot. Average crystal diameter was obtained from XRD analysis, HR-TEM and light scattering (PCS). The analysis of size data from HR-TEM images and PCS clearly indicated the formation of highly crystalline CeO{sub 2} particles in narrow size range. CeO{sub 2} nanocrystals precipitated at 35 {sup o}C were further annealed at temperatures in the range 300-700 {sup o}C. The activation energy for crystal growth during annealing is also calculated and is close to the reported values. An effort is made to predict the mechanism of crystal growth during the precipitation and annealing.

  10. Morphology controlled synthesis of monodisperse cobalt hydroxide for supercapacitor with high performance and long cycle life

    Science.gov (United States)

    Tang, Yongfu; Liu, Yanyan; Yu, Shengxue; Mu, Shichun; Xiao, Shaohua; Zhao, Yufeng; Gao, Faming

    2014-06-01

    A facile hydrothermal process with hexadecyltrimethyl ammonium bromide (CTAB) as the soft template is proposed to tune the morphology and size of cobalt hydroxide (Co(OH)2). Monodisperse β-phase Co(OH)2 nanowires with uniform size are obtained by controlling the CTAB content and the reaction time. Due to the uniform well-defined morphology and stable structure, the Co(OH)2 nanowires material exhibits high capacitive performance and long cycle life. The specific capacitance of the Co(OH)2 nanowires electrode is 358 F g-1 at 0.5 A g-1, and even 325 F g-1 at 10 A g-1. The specific capacitance retention is 86.3% after 5000 charge-discharge cycles at 2 A g-1. Moreover, the asymmetric supercapacitor is assembled with Co(OH)2 nanowires and nitrite acid treated activated carbon (NTAC), which shows an energy density of 13.6 Wh kg-1 at the power density of 153 W kg-1 under a high voltage of 1.6 V, and 13.1 Wh kg-1 even at the power density of 1.88 kW kg-1.

  11. Investigation of Monodisperse Dendrimeric Polysaccharide Nanoparticle Dispersions Using Small Angle Neutron Scattering

    Science.gov (United States)

    Atkinson, John; Nickels, Jonathan; Papp-Szabo, Erzsi; Katsaras, John; Dutcher, John

    2015-03-01

    Phytoglycogen is a highly branched polysaccharide that is very similar to the energy storage molecule glycogen. We have isolated monodisperse phytoglycogen nanoparticles from corn and these particles are attractive for applications in the cosmetic, food and beverage, and biomedical industries. Many of these promising applications are due to the special interaction between the nanoparticles and water, which results in: (1) high solubility; (2) low viscosity and high stability in aqueous dispersions; and (3) a remarkable capacity to sequester and retain water. Our rheology measurements indicate that the nanoparticles behave like hard spheres in water, with the viscosity diverging for concentrations >25% (w/w). Because of this, aqueous suspensions of phytoglycogen provide an ideal platform for detailed testing of theories of colloidal glasses and jamming. To further explore the interaction of the phytoglycogen particles and water, we have performed small angle neutron scattering (SANS) measurements on the Extended Q-Range SANS (EQ-SANS) diffractometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Measurements performed on phytoglycogen dispersions in mixtures of hydrogenated and deuterated water have allowed us to determine the particle size and average particle spacing as a function of the phytoglycogen concentration in the limits of dilute and concentrated dispersions.

  12. Bulk synthesis of monodisperse magnetic FeNi3 nanopowders by flow levitation method.

    Science.gov (United States)

    Chen, Shanjun; Chen, Yan; Kang, Xiaoli; Li, Song; Tian, Yonghong; Wu, Weidong; Tang, Yongjian

    2013-10-01

    In this work, a novel bulk synthesis method for monodisperse FeNi3 nanoparticles was developed by flow levitation method (FL). The Fe and Ni vapours ascending from the high temperature levitated droplet was condensed by cryogenic Ar gas under atmospheric pressure. X-ray diffraction was used to identify and characterize the crystal phase of prepared powders exhibiting a FeNi3 phase. The morphology and size of nanopowders were observed by transmission electron microscopy (TEM). The chemical composition of the nanoparticles was determined with energy dispersive spectrometer (EDS). The results indicated that the FeNi3 permalloy powders are nearly spherical-shaped with diameter about 50-200 nm. Measurement of the magnetic property of nanopowders by a superconducting quantum interference device (SQUID, Quantum Design MPMS-7) showed a symmetric hysteresis loop of ferromagnetic behavior with coercivity of 220 Oe and saturation magnetization of 107.17 emu/g, at 293 K. At 5 K, the obtained saturation magnetization of the sample was 102.16 emu/g. The production rate of FeNi3 nanoparticles was estimated to be about 6 g/h. This method has great potential in mass production of FeNi3 nannoparticles.

  13. Monodispersed MnO nanoparticles with epitaxial Mn{sub 3}O{sub 4} shells

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, A E; Rodriguez, G F [Department of Physics, University of California, San Diego La Jolla, CA 92093 (United States); Hong, J I; Fullerton, E E [Center for Magnetic Recording Research, University of California-San Diego La Jolla, CA 92093 (United States); An, K; Hyeon, T [National Creative Research Initiative Center for Oxide Nanocrystalline Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Agarwal, N; Smith, D J [School of Materials and Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

    2008-07-07

    We report the microstructural and magnetic properties of monodispersed nanoparticles (NPs) of antiferromagnetic MnO (T{sub N} = 118 K), with epitaxial ferrimagnetic Mn{sub 3}O{sub 4} (T{sub C} = 43 K) shells. Above T{sub C}, an unusually large magnetization is present, produced by the uncompensated spins (UCSs) on the surface of the MnO particles. These spins impart a net anisotropy to the MnO particles that is approximately three orders of magnitude larger than the bulk value. As a result, an anomalously high blocking temperature is exhibited by the MnO particles, and finite coercivity and exchange bias are present above T{sub C}. When field cooled below T{sub C}, a strong exchange bias was established in the Mn{sub 3}O{sub 4} shells as a result of high net anisotropy of the MnO particles. A large coercivity was also observed. Models of several aspects of the behaviour of this unusual system emphasized the essential role of the UCSs on the surfaces of the MnO NPs.

  14. Magnetically Triggered Monodispersed Nanocomposite Fabricated by Microfluidic Approach for Drug Delivery

    Directory of Open Access Journals (Sweden)

    O. Yassine

    2016-01-01

    Full Text Available Responsive microgel poly(N-isopropylacrylamide or PNIPAM is a gel that can swell or shrink in response to external stimuli (temperature, pH, etc.. In this work, a nanocomposite gel is developed consisting of PNIPAM and magnetic iron oxide nanobeads for controlled release of liquids (like drugs upon exposure to an alternating magnetic field. Microparticles of the nanocomposite are fabricated efficiently with a monodisperse size distribution and a diameter ranging from 20 to 500 µm at a rate of up to 1 kHz using a simple and inexpensive microfluidic system. The nanocomposite is heated through magnetic losses, which is exploited for a remotely stimulated liquid release. The efficiency of the microparticles for controlled drug release applications is tested with a solution of Rhodamine B as a liquid drug model. In continuous and pulsatile mode, a release of 7% and 80% was achieved, respectively. Compared to external thermal actuation that heats the entire surrounding or embedded heaters that need complex fabrication steps, the magnetic actuation provides localized heating and is easy to implement with our microfluidic fabrication method.

  15. Retention studies in rats exposed to monodisperse aerosols of /sup 198/Au labeled carnauba wax particles

    Energy Technology Data Exchange (ETDEWEB)

    Tarroni, G.; Bassi, P.; Belvisi, M.B.; Bianco, A.

    1981-01-01

    Rats were exposed to monodisperse carnauba wax aerosols labeled with colloidal /sup 198/Au and the retained activity was followed both in vivo and in the lungs of serially sacrified animals. In vitro and in vivo tests have shown low leaching rates of the label. The deposited activity could then be followed without correction for particle solubility. The activity in vivo shows a three-exponential decay, characterized by half-times of a few hours, one day, and one month corresponding to the clearance of the material deposited respectively in the extrathoracic airways, in the tracheo-bronchial, and in the alveolar regions. A correlation was found between long term cleared activity and particle size but no correlation was found between particle size and clearance half times in the size range investigated. Statistical evaluation of the activity vs time in vivo and in excised lungs has shown that the long term retained activity pertains to the alveolar region and, if a large number of animals is not used, more accurate data of pulmonary clearance can be obtained by in vivo measurements than by serial sacrifices.

  16. Dosimetry of 239Pu in dogs that inhaled monodisperse aerosols of 239PuO2

    International Nuclear Information System (INIS)

    Guilmette, R.A.; Muggenburg, B.A.; Hahn, F.F.; Mewhinney, J.A.; Seiler, F.A.; Boecker, B.B.; McClellan, R.O.

    1987-01-01

    Existing data from human exposure cases and experimental animal studies on the fate and dosimetry of inhaled insoluble Pu particles are inadequate to provide a comprehensive description and evaluation of the tissues at risk from the alpha radiations of Pu. To improve our knowledge of the dosimetry of inhaled insoluble 239 PuO 2 , this paper describes the uptake and retention of 239 Pu in the tissues of dogs that received single inhalation exposures to monodisperse aerosols of 239 PuO 2 . These data include times through 3 years after exposure. Using analytical functions fitted to each tissue data set, 1100-day radiation doses were calculated for lung, liver, skeleton, kidney, spleen, and tracheobronchial, mediastinal, sternal, hepatic, mandibular, and retropharyngeal lymph nodes. The dosimetry results suggest that the lung and lymph nodes associated with lymphatic drainage of the respiratory tract are the principal sites of alpha irradiation. However, the doses for the different respiratory tract lymph nodes vary by a factor of 2000, suggesting that assuming equivalent doses to respiratory tract lymph nodes is not appropriate. Other tissues receive radiation doses also but at levels one to three orders of magnitude less than the lung. Particle size dependence on uptake and retention was noted for the skeleton, mediastinal lymph nodes, hepatic lymph nodes, retropharyngeal lymph nodes, and mandibular lymph nodes

  17. Preparation of monodisperse microbubbles using an integrated embedded capillary T-junction with electrohydrodynamic focusing.

    Science.gov (United States)

    Parhizkar, Maryam; Stride, Eleanor; Edirisinghe, Mohan

    2014-07-21

    This work investigates the generation of monodisperse microbubbles using a microfluidic setup combined with electrohydrodynamic processing. A basic T-junction microfluidic device was modified by applying an electrical potential difference across the outlet channel. A model glycerol air system was selected for the experiments. In order to investigate the influence of the electric field strength on bubble formation, the applied voltage was increased systematically up to 21 kV. The effect of solution viscosity and electrical conductivity was also investigated. It was found that with increasing electrical potential difference, the size of the microbubbles reduced to ~25% of the capillary diameter whilst their size distribution remained narrow (polydispersity index ~1%). A critical value of 12 kV was found above which no further significant reduction in the size of the microbubbles was observed. The findings suggest that the size of the bubbles formed in the T-junction (i.e. in the absence of the electric field) is strongly influenced by the viscosity of the solution. The eventual size of bubbles produced by the composite device, however, was only weakly dependent upon viscosity. Further experiments, in which the solution electrical conductivity was varied by the addition of a salt indicated that this had a much stronger influence upon bubble size.

  18. Magnetically Triggered Monodispersed Nanocomposite Fabricated by Microfluidic Approach for Drug Delivery

    KAUST Repository

    Yassine, Omar

    2016-01-01

    Responsive microgel poly(N-isopropylacrylamide) or PNIPAM is a gel that can swell or shrink in response to external stimuli (temperature, pH, etc.). In this work, a nanocomposite gel is developed consisting of PNIPAM and magnetic iron oxide nanobeads for controlled release of liquids (like drugs) upon exposure to an alternating magnetic field. Microparticles of the nanocomposite are fabricated efficiently with a monodisperse size distribution and a diameter ranging from 20 to 500  µ m at a rate of up to 1 kHz using a simple and inexpensive microfluidic system. The nanocomposite is heated through magnetic losses, which is exploited for a remotely stimulated liquid release. The efficiency of the microparticles for controlled drug release applications is tested with a solution of Rhodamine B as a liquid drug model. In continuous and pulsatile mode, a release of 7% and 80% was achieved, respectively. Compared to external thermal actuation that heats the entire surrounding or embedded heaters that need complex fabrication steps, the magnetic actuation provides localized heating and is easy to implement with our microfluidic fabrication method.

  19. Undecylprodigiosin conjugated monodisperse gold nanoparticles efficiently cause apoptosis in colon cancer cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Nikodinovic-Runic, Jasmina; Mojic, Marija; Kang, Yijin; Maksimovic-Ivanic, Danijela; Mijatovic, Sanja; Vasiljevic, Branka; Stamenkovic, Vojislav R.; Senerovic, Lidija

    2014-01-01

    Bacterial pigment undecylprodigiosin (UP) was produced using Streptomyces sp. JS520 and conjugated to monodisperse gold nanoparticles (UP-Au). Both UP and UP-Au showed cytocidal activity towards melanoma (A375), lung carcinoma (A549), breast cancer (MCF-7) and colon cancer (HCT-116) cells, inducing apoptosis with IC50 values ranging from 0.4 to 4 mu g ml(-1). Unconjugated UP had a tendency to lose its activity over time and to change biophysical characteristics over pH. The loss of the pigment potency was overcome by conjugation with gold nanoparticles. UP-Au exhibited high stability over pH 3.8 to 7.4 and its activity remained unaffected in time. Nano-packing changed the mechanism of UP toxicity by converting the intracellular signals from a mitochondrial dependent to a mitochondrial independent apoptotic process. The availability of nonpyrogenic UP in high amounts, together with specific anticancer activity and improved stability in the complex with gold nanoparticles, presents a novel platform for further development of UP-Au complexes as an anticancer drug suitable for clinical applications.

  20. Monodispersed porous flowerlike PtAu nanocrystals as effective electrocatalysts for ethanol oxidation

    Science.gov (United States)

    Li, Shumin; Xu, Hui; Xiong, Zhiping; Zhang, Ke; Wang, Caiqin; Yan, Bo; Guo, Jun; Du, Yukou

    2017-11-01

    Designing and tuning the bimetallic nanoparticles with desirable morphology and structure can embody them with greatly enhanced electrocatalytic activity and stability towards liquid fuel oxidation. We herein reported a facile one-pot method for the controlled synthesis of monodispersed binary PtAu nanoflowers with abundant exposed surface area. Owing to its fantastic structure, synergistic and electronic effect, such as-prepared PtAu nanoflowers exhibited outstandingly high electrocatalytic activity with the mass activity of 6482 mA mg-1 towards ethanol oxidation, which is 28.3 times higher than that of commercial Pt/C (227 mA mg-1). More interesting, the present PtAu nanoflower catalysts are more stable for the ethanol oxidation reaction in the alkaline with lower current density decay and retained a much higher current density after successive CVs of 500 cycles than that of commercial Pt/C. This work may open a new way for maximizing the catalytic performance of electrocatalysts towards ethanol oxidation by synthesizing shape-controlled alloy nanoparticles with more surface active sites to enhance the performances of direct fuel cells reaction, chemical conversion, and beyond.

  1. A novel method for the synthesis of monodisperse gold-coated silica nanoparticles

    International Nuclear Information System (INIS)

    English, Michael D.; Waclawik, Eric R.

    2012-01-01

    Monodisperse silica nanoparticles were synthesised by the well-known Stober protocol, then dispersed in acetonitrile (ACN) and subsequently added to a bisacetonitrile gold(I) coordination complex ([Au(MeCN) 2 ] + ) in ACN. The silica hydroxyl groups were deprotonated in the presence of ACN, generating a formal negative charge on the siloxy groups. This allowed the [Au(MeCN) 2 ] + complex to undergo ligand exchange with the silica nanoparticles and form a surface coordination complex with reduction to metallic gold (Au 0 ) proceeding by an inner sphere mechanism. The residual [Au(MeCN) 2 ] + complex was allowed to react with water, disproportionating into Au 0 and Au(III), respectively, with the Au 0 adding to the reduced gold already bound on the silica surface. The so-formed metallic gold seed surface was found to be suitable for the conventional reduction of Au(III) to Au 0 by ascorbic acid (ASC). This process generated a thin and uniform gold coating on the silica nanoparticles. The silica NPs batches synthesised were in a size range from 45 to 460 nm. Of these silica NP batches, the size range from 400 to 480 nm were used for the gold-coating experiments.

  2. Synthetic Polymers at Interfaces: Monodisperse Emulsions Multiple Emulsions and Liquid Marbles

    Science.gov (United States)

    Sun, Guanqing

    The adsorption of polymeric materials at interfaces is an energetically favorable process which is investigated in much diversified fields, such as emulsions, bubbles, foams, liquid marbles. Pickering emulsion, which is emulsion stabilized by solid particles has been investigated for over one century and preparation of Pickering emulsion with narrow size distribution is crucial for both the theoretical study of the stabilization mechanism and practical application, such as templated fabrication of colloidosomes. The precise control over the size and functionality of polymer latices allows the preparation of monodisperse Pickering emulsions with desired sizes through SPG membrane emulsification at rather rapid rate compared to microfludic production. Double or multiple emulsions have long been investigated but its rapid destabilization has always been a major obstacle in applying them into practical applications. The modern living polymerization techniques allow us to prepare polymers with designed structure of block copolymers which makes it possible to prepare ultra-stable multiple emulsions. The precise tuning of the ratio of hydrophobic part over the hydrophilic can unveil the stabilization mechanism. Liquid marble is a new type of materials of which liquid droplets are coated by dry particles. The coating of an outer layer of dry particles renders the liquid droplets non-sticky at solid surface which is useful in transportation of small amount of liquid without leakage at extreme low friction force. The property of liquid marbles relies largely on the stabilizers and the drying condition of polymeric latices is shown to have great influence on the property of liquid marbles. Firstly, an introduction to the interfacial and colloidal science with special attention to topics on emulsions, multiple emulsion and liquid marbles is given in Chapter 1. The unique features of an interface and a discussion on the definition of colloids are introduced prior to the

  3. Quantitation of MRI sensitivity to quasi-monodisperse microbubble contrast agents for spatially resolved manometry.

    Science.gov (United States)

    Bencsik, Martin; Al-Rwaili, Amgad; Morris, Robert; Fairhurst, David J; Mundell, Victoria; Cave, Gareth; McKendry, Jonathan; Evans, Stephen

    2013-11-01

    The direct in-vivo measurement of fluid pressure cannot be achieved with MRI unless it is done with the contribution of a contrast agent. No such contrast agents are currently available commercially, whilst those demonstrated previously only produced qualitative results due to their broad size distribution. Our aim is to quantitate then model the MR sensitivity to the presence of quasi-monodisperse microbubble populations. Lipid stabilised microbubble populations with mean radius 1.2 ± 0.8 μm have been produced by mechanical agitation. Contrast agents with increasing volume fraction of bubbles up to 4% were formed and the contribution the bubbles bring to the relaxation rate was quantitated. A periodic pressure change was also continuously applied to the same contrast agent, until MR signal changes were only due to bubble radius change and not due to a change in bubble density. The MR data compared favourably with the prediction of an improved numerical simulation. An excellent MR sensitivity of 23 % bar(-1) has been demonstrated. This work opens up the possibility of generating microbubble preparations tailored to specific applications with optimised MR sensitivity, in particular MRI based in-vivo manometry. Copyright © 2012 Wiley Periodicals, Inc.

  4. Repetitive heterocoagulation of oppositely charged particles for enhancement of magnetic nanoparticle loading into monodisperse silica particles.

    Science.gov (United States)

    Matsumoto, Hideki; Nagao, Daisuke; Konno, Mikio

    2010-03-16

    Oppositely charged particles were repetitively heterocoagulated to fabricate highly monodisperse magnetic silica particles with high loading of magnetic nanoparticles. Positively charged magnetic nanoparticles prepared by surface modification with N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TSA) were used to heterocoagulate with silica particles under basic conditions to give rise to negative silica surface charge and prevent the oxidation of the magnetic nanoparticles. The resultant particles of silica core homogeneously coated with the magnetic nanoparticles were further coated with thin silica layer with sodium silicate in order to enhance colloidal stability and avoid desorption of the magnetic nanoparticles from the silica cores. Five repetitions of the heterocoagulation and the silica coating could increase saturation magnetization of the magnetic silica particles to 27.7 emu/g, keeping the coefficient of variation of particle sizes (C(V)) less than 6.5%. Highly homogeneous loading of the magnetic component was confirmed by measuring Fe-to-Si atomic ratios of individual particles with energy dispersive X-ray spectroscopy.

  5. Recent developments in inorganically filled carbon nanotubes: successes and challenges

    Directory of Open Access Journals (Sweden)

    Ujjal K Gautam, Pedro M F J Costa, Yoshio Bando, Xiaosheng Fang, Liang Li, Masataka Imura and Dmitri Golberg

    2010-01-01

    Full Text Available Carbon nanotubes (CNTs are a unique class of nanomaterials that can be imagined as rolled graphene sheets. The inner hollow of a CNT provides an extremely small, one-dimensional space for storage of materials. In the last decade, enormous effort has been spent to produce filled CNTs that combine the properties of both the host CNT and the guest filling material. CNTs filled with various inorganic materials such as metals, alloys, semiconductors and insulators have been obtained using different synthesis approaches including capillary filling and chemical vapor deposition. Recently, several potential applications have emerged for these materials, such as the measurement of temperature at the nanoscale, nano-spot welding, and the storage and delivery of extremely small quantities of materials. A clear distinction between this class of materials and other nanostructures is the existence of an enormous interfacial area between the CNT and the filling matter. Theoretical investigations have shown that the lattice mismatch and strong exchange interaction of CNTs with the guest material across the interface should result in reordering of the guest crystal structure and passivation of the surface dangling bonds and thus yielding new and interesting physical properties. Despite preliminary successes, there remain many challenges in realizing applications of CNTs filled with inorganic materials, such as a comprehensive understanding of their growth and physical properties and control of their structural parameters. In this article, we overview research on filled CNT nanomaterials with special emphasis on recent progress and key achievements. We also discuss the future scope and the key challenges emerging out of a decade of intensive research on these fascinating materials.

  6. Environmental, Health, and Safety Research Needs for Engineered Nanoscale Materials

    National Research Council Canada - National Science Library

    Alderson, Norris; Alexander, Catherine; Merzbacher, Celia; Chernicoff, William; Middendorf, Paul; Beck, Nancy; Chow, Flora; Poster, Dianne; Danello, Mary Ann; Barrera, Enriqueta

    2006-01-01

    ...) research and information needs related to understanding and management of potential risks of engineered nanoscale materials that may be used, for example, in commercial or consumer products, medical...

  7. Heat-resistant inorganic binders.

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich,

    2017-04-01

    Full Text Available The authors consider some aspects of production of inorganic heat-resistant composite materials in which new classes of inorganic binders - the basic salts of various metals – are applied. The possibility to use hydroxochlorides and hydroxonitrates of aluminum, zirconium, chromium and a number of other metals as the binder has been shown. The main products of the thermal decomposition of all types of binders discussed in this paper are nano-dispersed highly refractory oxides. Increased pressure in the manufacture of these materials shifts the position of the minimum of the dependence «production strength – production temperature» in the direction of low temperatures. This effect is caused by decreased film thickness of the binder located between filler particles and hence by increased rate of transfer of the matter to the interface and by facilitated sintering process. Materials based on the systems containing chromium and some other elements in transitional oxidation states are colour. For this reason, they have the worst thermal conductivity under the same heat resistance compared to colorless materials.

  8. Investigations of inorganic and hybrid inorganic-organic nanostructures

    Science.gov (United States)

    Kam, Kinson Chihang

    This thesis focuses on the exploratory synthesis and characterization of inorganic and hybrid inorganic-organic nanomaterials. In particular, nanostructures of semiconducting nitrides and oxides, and hybrid systems of nanowire-polymer composites and framework materials, are investigated. These materials are characterized by a variety of techniques for structure, composition, morphology, surface area, optical properties, and electrical properties. In the study of inorganic nanomaterials, gallium nitride (GaN), indium oxide (In2O3), and vanadium dioxide (VO2) nanostructures were synthesized using different strategies and their physical properties were examined. GaN nanostructures were obtained from various synthetic routes. Solid-state ammonolysis of metastable gamma-Ga2O 3 nanoparticles was found to be particularly successful; they achieved high surface areas and photoluminescent study showed a blue shift in emission as a result of surface and size defects. Similarly, In2O3 nanostructures were obtained by carbon-assisted solid-state syntheses. The sub-oxidic species, which are generated via a self-catalyzed vapor-liquid-solid mechanism, resulted in 1D nanostructures including nanowires, nanotrees, and nanobouquets upon oxidation. On the other hand, hydrothermal methods were used to obtain VO2 nanorods. After post-thermal treatment, infrared spectroscopy demonstrated that these nanorods exhibit a thermochromic transition with temperature that is higher by ˜10°C compared to the parent material. The thermochromic behavior indicated a semiconductor-to-metal transition associated with a structural transformation from monoclinic to rutile. The hybrid systems, on the other hand, enabled their properties to be tunable. In nanowire-polymer composites, zinc oxide (ZnO) and silver (Ag) nanowires were synthesized and incorporated into polyaniline (PANI) and polypyrrole (PPy) via in-situ and ex-situ polymerization method. The electrical properties of these composites are

  9. Simulation of capillary bridges between nanoscale particles.

    Science.gov (United States)

    Dörmann, Michael; Schmid, Hans-Joachim

    2014-02-04

    Capillary forces are very important as they exceed in general other adhesion forces. But at the same time the exact calculation of these forces is very complex, so often assumptions and approximations are used. Previous research was done with regard to micrometer sized particles, but the behavior of nanoscale particles is different. Hence, the results for micrometer sized particles cannot be directly transferred when considering nanoscale particles. Therefore, a simulation method was developed to calculate numerically the shape of a rotationally symmetrical capillary bridge between two spherical particles or a particle and a plate. The capillary bridge in the gap between the particles is formed due to capillary condensation and is in thermodynamic equilibrium with the gas phase. Hence the Kelvin equation and the Young-Laplace equation can be used to calculate the profile of the capillary bridge, depending on the relative humidity of the surrounding air. The bridge profile consists of several elements that are determined consecutively and interpolated linearly. After the shape is determined, the volume and force, divided into capillary pressure force and surface tension force, can be calculated. The validation of this numerical model will be shown by comparison with several different analytical calculations for micrometer-sized particles. Furthermore, it is demonstrated that two often used approximations, (1) the toroidal approximation and (2) the use of an effective radius, cannot be used for nanoscale particles without remarkable mistake. It will be discussed how the capillary force and its components depend on different parameters, like particle size, relative humidity, contact angle, and distance, respectively. The rupture of a capillary bridge due to particle separation will also be presented.

  10. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun

    2011-01-01

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  11. Probing nanoscale ferroelectricity by ultraviolet Raman spectroscopy.

    Science.gov (United States)

    Tenne, D A; Bruchhausen, A; Lanzillotti-Kimura, N D; Fainstein, A; Katiyar, R S; Cantarero, A; Soukiassian, A; Vaithyanathan, V; Haeni, J H; Tian, W; Schlom, D G; Choi, K J; Kim, D M; Eom, C B; Sun, H P; Pan, X Q; Li, Y L; Chen, L Q; Jia, Q X; Nakhmanson, S M; Rabe, K M; Xi, X X

    2006-09-15

    We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (Tc) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO3 layers adjacent to them. Tc was tuned by approximately 500 kelvin by varying the thicknesses of the BaTiO3 and SrTiO3 layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.

  12. Synthesis, dynamics and photophysics of nanoscale systems

    Science.gov (United States)

    Mirkovic, Tihana

    The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained

  13. Micro- and nanoscale phenomena in tribology

    CERN Document Server

    Chung, Yip-Wah

    2011-01-01

    Drawn from presentations at a recent National Science Foundation Summer Institute on Nanomechanics, Nanomaterials, and Micro/Nanomanufacturing, Micro- and Nanoscale Phenomena in Tribology explores the convergence of the multiple science and engineering disciplines involved in tribology and the connection from the macro to nano world. Written by specialists from computation, materials science, mechanical engineering, surface physics, and chemistry, each chapter provides up-to-date coverage of both basic and advanced topics and includes extensive references for further study.After discussing the

  14. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  15. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Science.gov (United States)

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2014-07-22

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  16. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Science.gov (United States)

    Bond, Tiziana C; Miles, Robin; Davidson, James; Liu, Gang Logan

    2015-11-03

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  17. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Science.gov (United States)

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2015-07-14

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  18. Synthesis, characterization and magnetic properties of monodisperse Ni, Zn-ferrite nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sanjeev, E-mail: sanjeevkumar.dubey2@gmail.com [University of Petroleum and Energy Studies, Dehradun, Uttarakhand (India); Kumar, Pankaj [University of Petroleum and Energy Studies, Dehradun, Uttarakhand (India); Singh, Vaishali [University School of Basic and Applied Science (India); Kumar Mandal, Uttam [University of Chemical Technology, GGS Indraprastha University, Sector 16, Dwarka, Delhi 110403 (India); Kumar Kotnala, Ravinder [National Physical laboratory, New Delhi 110012 (India)

    2015-04-01

    Synthesization of monodisperse Ni, Zn-ferrite (Ni{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4}, x=1, 0.8, 0.6, 0.5, 0.4, 0.2, 0.0) nanocrystals has been achieved by the inverse microemulsion method using CTAB as surfactant and kerosene as an oil phase. The detailed characterization of the synthesized nanocrystals and measurement of the magnetic properties has been done by techniques like X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM), Fourier transform infrared spectroscopy (FITR) and Vibrating Sample Magnetometer (VSM) respectively. The relationship between the structure and composition of the nanocrystals with magnetic properties has been investigated. The nanocrystals size is found to be in the range 1–5 nm. The effect of Zn substitution on size and magnetic properties has been studied. It has been observed that magnetism changed from ferromagnetic at X= 0 to super paramagnetic to paramagnetic at X=1 as Zn concentration increased. The Curie temperature is found to decrease with an increase in Zn concentration. - Highlights: • Reverse microemulsion route is very facile route for synthesis of Ni{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} ferrite. • Presence of Zn changes the structural and magnetic properties of the Zn substituted NiFe{sub 2}O{sub 4.} • The lattice constant increases with the increase in Zn substitution. • The curie temperature decreases with Zn concentration appreciably. • Magnetic behavior varies from ferromagnetic at x=0 to superparamagnetic to paramagnetic at x=1.

  19. Ambiguity assessment of small-angle scattering curves from monodisperse systems.

    Science.gov (United States)

    Petoukhov, Maxim V; Svergun, Dmitri I

    2015-05-01

    A novel approach is presented for an a priori assessment of the ambiguity associated with spherically averaged single-particle scattering. The approach is of broad interest to the structural biology community, allowing the rapid and model-independent assessment of the inherent non-uniqueness of three-dimensional shape reconstruction from scattering experiments on solutions of biological macromolecules. One-dimensional scattering curves recorded from monodisperse systems are nowadays routinely utilized to generate low-resolution particle shapes, but the potential ambiguity of such reconstructions remains a major issue. At present, the (non)uniqueness can only be assessed by a posteriori comparison and averaging of repetitive Monte Carlo-based shape-determination runs. The new a priori ambiguity measure is based on the number of distinct shape categories compatible with a given data set. For this purpose, a comprehensive library of over 14,000 shape topologies has been generated containing up to seven beads closely packed on a hexagonal grid. The computed scattering curves rescaled to keep only the shape topology rather than the overall size information provide a `scattering map' of this set of shapes. For a given scattering data set, one rapidly obtains the number of neighbours in the map and the associated shape topologies such that in addition to providing a quantitative ambiguity measure the algorithm may also serve as an alternative shape-analysis tool. The approach has been validated in model calculations on geometrical bodies and its usefulness is further demonstrated on a number of experimental X-ray scattering data sets from proteins in solution. A quantitative ambiguity score (a-score) is introduced to provide immediate and convenient guidance to the user on the uniqueness of the ab initio shape reconstruction from the given data set.

  20. Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yan-yu [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Yang, Hui, E-mail: 549456369@qq.com [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Tao [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Chuang [Department of Highway & Bridge, Shaanxi Railway Institute, Weinan 714000 (China)

    2016-11-25

    Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag{sup +} (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO{sub 3}) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO{sub 3} concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV–vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10–16 nm. FTIR analysis revealed that biological macromolecules with groups of −NH{sub 2}, −OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications. - Highlights: • Monodisperse silver nanoparticles were first prepared by a green synthetical way through Ginkgo Biloba leaf extract. • The synthesized AgNPs is of high crystallinity, stable and good dispersion with smaller sizes between 10–16 nm. • The achieved AgNPs exhibits good antibacterial activities. • The biosynthesis method is advantageous for its cost effectiveness, availability, portability, nontoxic and environmentally benign.

  1. Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

    International Nuclear Information System (INIS)

    Ren, Yan-yu; Yang, Hui; Wang, Tao; Wang, Chuang

    2016-01-01

    Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag + (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO 3 ) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO 3 concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV–vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10–16 nm. FTIR analysis revealed that biological macromolecules with groups of −NH 2 , −OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications. - Highlights: • Monodisperse silver nanoparticles were first prepared by a green synthetical way through Ginkgo Biloba leaf extract. • The synthesized AgNPs is of high crystallinity, stable and good dispersion with smaller sizes between 10–16 nm. • The achieved AgNPs exhibits good antibacterial activities. • The biosynthesis method is advantageous for its cost effectiveness, availability, portability, nontoxic and environmentally benign.

  2. Medicinal Uses of Inorganic Compounds - 2

    Indian Academy of Sciences (India)

    In the first part of this article, we described medicinal uses of inorganic compounds relating to cancer care, infection and diabetic control, neurological, cardiovascular and in- flammatory diseases. This article contains further infor- mation on the medicinal uses of inorganic compounds as therapeutic and diagnostic in ...

  3. Recent Advances in Bio-inorganic Chemistry

    Indian Academy of Sciences (India)

    Unknown

    Bio-inorganic chemistry has developed rapidly in recent years. A number of laboratories in India have made significant contributions to this area. The motivation in bringing out this special issue on Bio-inorganic. Chemistry is to highlight the recent work emerging from India in this important and fascinating interdisci-.

  4. Attachment of inorganic moieties onto aliphatic polyurethanes

    Directory of Open Access Journals (Sweden)

    Eliane Ayres

    2007-06-01

    Full Text Available Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU having different macromolecular architectures. Polyurethanes were synthesized using a polyether diol and dicyclohexylmethane 4,4' diisocyanate (H12-MDI. Polyurethanes having carboxylic acid groups were also produced by introducing 2,2- bis (hydroxymethyl propionic acid in the polymerization process. Inorganic functionalities were inserted into polyurethanes by reacting isocyanate end capped chains with aminopropyltriethoxysilane followed by tetraethoxysilane. PU having carboxylic acid groups yielded transparent samples after the incorporation of inorganic entities, as an evidence of smaller and better dispersed inorganic entities in the polymer network. FTIR and swelling measurements showed that polyurethanes having carboxylic acid groups had inorganic domains less packed, condensed and cross-linked when compared to polyurethanes with no carboxylic acid groups. Results also suggested that the progressive incorporation of inorganic moieties in both types of polyurethanes occurred in regions previously activated with inorganic functionalities, instead of by the creation of new domains. The temperatures of thermal decomposition and glass transition were also shifted to higher temperatures when inorganic functionalities were incorporated into polyurethanes.

  5. Uptake of inorganic contaminants by pteridophytes

    International Nuclear Information System (INIS)

    Zheng Jiemin; Chen Ziyuan; Tang Shirong; Guangzhou Univ., Guangzhou; Ding Bingyang

    2005-01-01

    The review covers results at home and abroad in terms of uptake of inorganic contaminants by pteridophytes, and suggests pteridophytes' significance in phytoremediation; the mechanisms related to uptake of inorganic contaminants by pteridophytes and some methods and means used for research on the mechanism are also introduced; the authors' viewpoints on future development trends are presented in this paper. (authors)

  6. Ultrasound exfoliation of inorganic analogues of graphene

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Henych, Jiří; Slušná, Michaela; Ecorchard, Petra

    2014-01-01

    Roč. 9, APR (2014), s. 1-14 ISSN 1556-276X R&D Projects: GA ČR(CZ) GA14-05146S Institutional support: RVO:61388980 Keywords : Ultrasound * Exfoliation * Graphene inorganic analogues Subject RIV: CA - Inorganic Chemistry Impact factor: 2.779, year: 2014

  7. Visualizing copper assisted graphene growth in nanoscale

    Science.gov (United States)

    Rosmi, Mohamad Saufi; Yusop, Mohd Zamri; Kalita, Golap; Yaakob, Yazid; Takahashi, Chisato; Tanemura, Masaki

    2014-01-01

    Control synthesis of high quality large-area graphene on transition metals (TMs) by chemical vapor deposition (CVD) is the most fascinating approach for practical device applications. Interaction of carbon atoms and TMs is quite critical to obtain graphene with precise layer number, crystal size and structure. Here, we reveal a solid phase reaction process to achieve Cu assisted graphene growth in nanoscale by in-situ transmission electron microscope (TEM). Significant structural transformation of amorphous carbon nanofiber (CNF) coated with Cu is observed with an applied potential in a two probe system. The coated Cu particle recrystallize and agglomerate toward the cathode with applied potential due to joule heating and large thermal gradient. Consequently, the amorphous carbon start crystallizing and forming sp2 hybridized carbon to form graphene sheet from the tip of Cu surface. We observed structural deformation and breaking of the graphene nanoribbon with a higher applied potential, attributing to saturated current flow and induced Joule heating. The observed graphene formation in nanoscale by the in-situ TEM process can be significant to understand carbon atoms and Cu interaction. PMID:25523645

  8. Catalysis at the nanoscale may change selectivity.

    Science.gov (United States)

    Costentin, Cyrille; Savéant, Jean-Michel

    2016-10-18

    Among the many virtues ascribed to catalytic nanoparticles, the prospect that the passage from the macro- to the nanoscale may change product selectivity attracts increasing attention. To date, why such effects may exist lacks explanation. Guided by recent experimental reports, we propose that the effects may result from the coupling between the chemical steps in which the reactant, intermediates, and products are involved and transport of these species toward the catalytic surface. Considering as a thought experiment the competitive formation of hydrogen and formate upon reduction of hydrogenocarbonate ions on metals like palladium or platinum, a model is developed that allows one to identify the governing parameters and predict the effect of nanoscaling on selectivity. The model leads to a master equation relating product selectivity and thickness of the diffusion layer. The latter parameter varies considerably upon passing from the macro- to the nanoscale, thus predicting considerable variations of product selectivity. These are subtle effects in the sense that the same mechanism might exhibit a reverse variation of the selectivity if the set of parameter values were different. An expression is given that allows one to predict the direction of the effect. There has been a tendency to assign the catalytic effects of nanoscaling to chemical reactivity changes of the active surface. Such factors might be important in some circumstances. We, however, insist on the likely role of short-distance transport on product selectivity, which could have been thought, at first sight, as the exclusive domain of chemical factors.

  9. Computer simulations for the nano-scale

    International Nuclear Information System (INIS)

    Stich, I.

    2007-01-01

    A review of methods for computations for the nano-scale is presented. The paper should provide a convenient starting point into computations for the nano-scale as well as a more in depth presentation for those already working in the field of atomic/molecular-scale modeling. The argument is divided in chapters covering the methods for description of the (i) electrons, (ii) ions, and (iii) techniques for efficient solving of the underlying equations. A fairly broad view is taken covering the Hartree-Fock approximation, density functional techniques and quantum Monte-Carlo techniques for electrons. The customary quantum chemistry methods, such as post Hartree-Fock techniques, are only briefly mentioned. Description of both classical and quantum ions is presented. The techniques cover Ehrenfest, Born-Oppenheimer, and Car-Parrinello dynamics. The strong and weak points of both principal and technical nature are analyzed. In the second part we introduce a number of applications to demonstrate the different approximations and techniques introduced in the first part. They cover a wide range of applications such as non-simple liquids, surfaces, molecule-surface interactions, applications in nano technology, etc. These more in depth presentations, while certainly not exhaustive, should provide information on technical aspects of the simulations, typical parameters used, and ways of analysis of the huge amounts of data generated in these large-scale supercomputer simulations. (author)

  10. Nanoscale Science and Engineering in Romania

    International Nuclear Information System (INIS)

    Dascalu, Dan; Topa, Vladimir; Kleps, Irina

    2001-01-01

    In spite of difficult working conditions and with very low financial support, many groups from Romania are involved in emerging fields, such as the nanoscale science and technology. Until the last years, this activity was developed without a central coordination and without many interactions between these research groups. In the year 2000, some of the institutes and universities active in the nanotechnology field in Romania founded the MICRONANOTECH network. The aim of this paper is to emphasize the main activities and results of the Romanian groups working in this novel domain. Most of the groups are deal with the nanomaterial technology and only few of them have activities in nanostructure science and engineering, in new concepts and device modeling and technology. This paper describes the nanotechnology research development in two of the most significant institutes from Romania: Centre for Nanotechnologies from National Institute for Research and Development in Microtehnologies (IMT-Bucharest) and from National Institute for Research and Development in Materials Physics (INCD-FM), Magurele. The Romanian research results in nanotechnology field were presented in numerous papers presented in international conferences or published in national and international journals. They are also presented in patents, international awards and fellowships. The research effort and financial support are outlined. Some future trends of the Romanian nanoscale science and technology research are also described

  11. Nanomaterial Case Studies: Nanoscale Titanium Dioxide in ...

    Science.gov (United States)

    EPA announced the availability of the final report, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen. This report is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: (1) as an agent for removing arsenic from drinking water; and (2) as an active ingredient in topical sunscreen. These case studies are organized around a comprehensive environmental assessment (CEA) framework that combines a product life cycle perspective with the risk assessment paradigm. They are intended to help identify what may need to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. These “case studies” do not represent completed or even preliminary assessments, nor are they intended to serve as a basis for risk management decisions in the near term on these specific uses of nano TiO2. Rather, the intent is to use this document in developing the scientific and technical information needed for future assessment efforts.

  12. Improving Neural Recording Technology at the Nanoscale

    Science.gov (United States)

    Ferguson, John Eric

    Neural recording electrodes are widely used to study normal brain function (e.g., learning, memory, and sensation) and abnormal brain function (e.g., epilepsy, addiction, and depression) and to interface with the nervous system for neuroprosthetics. With a deep understanding of the electrode interface at the nanoscale and the use of novel nanofabrication processes, neural recording electrodes can be designed that surpass previous limits and enable new applications. In this thesis, I will discuss three projects. In the first project, we created an ultralow-impedance electrode coating by controlling the nanoscale texture of electrode surfaces. In the second project, we developed a novel nanowire electrode for long-term intracellular recordings. In the third project, we created a means of wirelessly communicating with ultra-miniature, implantable neural recording devices. The techniques developed for these projects offer significant improvements in the quality of neural recordings. They can also open the door to new types of experiments and medical devices, which can lead to a better understanding of the brain and can enable novel and improved tools for clinical applications.

  13. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  14. Frontier in nanoscale flows fractional calculus and analytical methods

    CERN Document Server

    Lewis, Roland; Liu, Hong-yan

    2014-01-01

    This ebook covers the basic properties of nanoscale flows, and various analytical and numerical methods for nanoscale flows and environmental flows. This ebook is a good reference not only for audience of the journal, but also for various communities in mathematics, nanotechnology and environmental science.

  15. Development of cement material using inorganic additives

    International Nuclear Information System (INIS)

    Toyohara, Masumitsu; Satou, Tatsuaki; Wada, Mikio; Ishii, Tomoharu; Matsuo, Kazuaki.

    1997-01-01

    Inorganic admixtures to enhance the fluidity of cement material was developed. These admixtures turned into easy to immobilize the miscellaneous radioactive waste using cement material. It was found that the ζ potential of cement particles was directly proportional to the content of the inorganic admixtures in cement paste and the particles of cement were dispersed at the high ζ potential. The condensed sodium phosphate, which was the main component of the inorganic admixtures, retarded the dissolution of Ca 2+ ion from the cement, and generated the colloids by incorporating dissolved Ca 2+ ion. The cement material containing the inorganic admixtures was found to have the same mechanical strength and adsorption potential of radionuclides in comparison to normal cement materials. It was confirmed that the cement material containing the inorganic admixture was effectively filled gaps of miscellaneous radioactive waste. (author)

  16. Welcome to Inorganics: A New Open Access, Inclusive Forum for Inorganic Chemistry

    Directory of Open Access Journals (Sweden)

    Duncan H. Gregory

    2013-06-01

    Full Text Available One of the beauties of inorganic chemistry is its sheer diversity. Just as chemistry sits at the centre of the sciences, inorganic chemistry sits at the centre of chemistry itself. Inorganic chemists are fortunate in having the entire periodic table at their disposal, providing a palette for the creation of a multitude of rich and diverse compounds and materials from the simplest salts to the most complex of molecular species. It follows that the language of inorganic chemistry can thus be a demanding one, accommodating sub-disciplines with very different perspectives and frames of reference. One could argue that it is the unequivocal breadth of inorganic chemistry that empowers inorganic chemists to work at the interfaces, not just between the traditional Inorganic-Organic-Physical boundaries of the discipline, but in the regions where chemistry borders the other physical and life sciences, engineering and socio-economics. [...

  17. Surface modification of gas diffusion layers by inorganic nanomaterials for performance enhancement of proton exchange membrane fuel cells at low RH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cindrella, L. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, 7001 E Williams Field Rd., Mesa, AZ 85212 (United States); Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015 (India); Kannan, A.M. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, 7001 E Williams Field Rd., Mesa, AZ 85212 (United States); Ahmad, R.; Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States)

    2009-08-15

    Prompted by our earlier study that fumed silica on gas diffusion layer (GDL) favored a performance improvement of the single fuel cell at lower RH conditions, the present study has been carried out with inorganic oxides in the nanoscale such as TiO{sub 2}, Al{sub 2}O{sub 3}, commercially available mixed oxides, hydrophilic silica and aerosil silica. The structure of each of the oxide coating on the GDL surface has resulted in refinement with graded pore dimension as seen from the Hg porosimetry data. The fuel cell evaluation at various RH conditions (50-100%) revealed that the performance of all the inorganic oxides loaded GDL is very high compared to that of pristine GDL. The results confirm our earlier observation that inorganic oxides on GDL bring about structural refinement favorable for the transport of gases, and their water retaining capacity enable a high performance of the fuel cell even at low RH conditions. (author)

  18. Macrocyclic receptors immobilized to monodisperse porous polymer particles by chemical grafting and physical impregnation for strontium capture: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yang [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); Du, Yi [Department of Chemical Engineering, Laboratory for Advanced Materials, Tsinghua University, Beijing (China); Lv, Dachao [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); Ye, Gang, E-mail: yegang@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China); Wang, Jianchen [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing (China)

    2014-06-01

    Graphical abstract: Macrocyclic receptors grafted to monodisperse porous polymer particles for Sr(II) capture. - Highlights: • Synthesis of novel selective Sr adsorbent grafted with macrocyclic receptors. • New monodisperse porous polymer particles used to promote Sr adsorption. • Comparative study and discussion on adsorption behaviour and mechanism. • A chromatographic process proposed for Sr separation in simulated HLLW. - Abstract: Separation of strontium is of great significance for radioactive waste treatment and environmental remediation after nuclear accidents. In this work, a novel class of adsorbent (Crown-g-MPPPs) was synthesized by chemical grafting a macrocyclic ether receptor to monodisperse porous polymer particles (MPPPs) for strontium adsorption. Meanwhile, a counterpart material (Crown@MPPPs) with the receptor molecules immobilized to the MPPPs substrate by physical impregnation was prepared. To investigate how the immobilization manner and distribution of the receptors influence the adsorption ability, a comparative study on the adsorption behaviour of the two materials towards Sr(II) in HNO{sub 3} media was accomplished. Due to the shorter diffusion path and covalently-bonded structure, Crown-g-MPPPs showed faster adsorption kinetics and better stability for cycle use. While Crown@MPPPs had the advantages of facile synthesis and higher adsorption capacity, owing to the absence of conformational constraint to form complexation with Sr(II). Kinetic functions (Lagergren pseudo-first-order/pseudo-second-order functions) and adsorption isotherm models (Langmuir/Freundlich models) were used to fit the experimental data and examine the adsorption mechanism. On this basis, a chromatographic process was proposed by using Crown@MPPPs for an effective separation of Sr(II) (91%) in simulated high level liquid waste (HLLW)

  19. Bio-inspired routes for synthesizing efficient nanoscale platinum electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jennifer N. [Univ. of California, San Diego, CA (United States); Wang, Joseph [Univ. of California, San Diego, CA (United States)

    2014-08-31

    The overall objective of the proposed research is to use fundamental advances in bionanotechnology to design powerful platinum nanocrystal electrocatalysts for fuel cell applications. The new economically-viable, environmentally-friendly, bottom-up biochemical synthetic strategy will produce platinum nanocrystals with tailored size, shape and crystal orientation, hence leading to a maximum electrochemical reactivity. There are five specific aims to the proposed bio-inspired strategy for synthesizing efficient electrocatalytic platinum nanocrystals: (1) isolate peptides that both selectively bind particular crystal faces of platinum and promote the nucleation and growth of particular nanocrystal morphologies, (2) pattern nanoscale 2-dimensional arrays of platinum nucleating peptides from DNA scaffolds, (3) investigate the combined use of substrate patterned peptides and soluble peptides on nanocrystal morphology and growth (4) synthesize platinum crystals on planar and large-area carbon electrode supports, and (5) perform detailed characterization of the electrocatalytic behavior as a function of catalyst size, shape and morphology. Project Description and Impact: This bio-inspired collaborative research effort will address key challenges in designing powerful electrocatalysts for fuel cell applications by employing nucleic acid scaffolds in combination with peptides to perform specific, environmentally-friendly, simultaneous bottom-up biochemical synthesis and patterned assembly of highly uniform and efficient platinum nanocrystal catalysts. Bulk synthesis of nanoparticles usually produces a range of sizes, accessible catalytic sites, crystal morphologies, and orientations, all of which lead to inconsistent catalytic activities. In contrast, biological systems routinely demonstrate exquisite control over inorganic syntheses at neutral pH and ambient temperature and pressures. Because the orientation and arrangement of the templating biomolecules can be precisely

  20. High performance of visible-NIR broad spectral photocurrent application of monodisperse PbSe nanocubes decorated on rGO sheets

    Science.gov (United States)

    Ghorban Shiravizadeh, A.; Elahi, S. M.; Sebt, S. A.; Yousefi, Ramin

    2018-02-01

    In this work, the photoresponse performance of monodisperse PbSe nanocubes in the range of visible and near-infrared (NIR) (400-1500 nm) regions was enhanced by reduced graphene oxide (rGO). A simple cost-effective method is presented to synthesize monodisperse PbSe nanocubes (NCs) that are decorated on the rGO sheets. By the addition of PbSe/rGO nanocomposites with different rGO concentrations, pristine PbSe NCs were synthesized with the same method. Microscopy images showed that the size of NCs was smaller than the exciton Bohr radius (46 nm) of PbSe bulk. Therefore, the UV-Vis-IR spectroscopy result revealed that the PbSe/rGO samples had absorption peaks in the NIR region around 1650 nm and showed a blue shift compared to the absorption peak of the PbSe bulk. J-V measurements of the samples indicated that monodisperse PbSe/rGO nanocomposites had a higher resistance than the other samples under dark condition. On the other hand, the resistance of the monodisperse PbSe/rGO nanocomposites decreased under different light source illuminations while the resistance of the other samples was increased under illumination. Photodetector measurements indicated that the monodisperse morphology of the PbSe NCs enhanced the photoresponse speed and photocurrent intensity. In addition, responsivity (R) and detectivity (D*) of the samples were higher in the NIR region.

  1. Comparative DNA isolation behaviours of silica and polymer based sorbents in batch fashion: monodisperse silica microspheres with bimodal pore size distribution as a new sorbent for DNA isolation.

    Science.gov (United States)

    Günal, Gülçin; Kip, Çiğdem; Eda Öğüt, S; İlhan, Hasan; Kibar, Güneş; Tuncel, Ali

    2018-02-01

    Monodisperse silica microspheres with bimodal pore-size distribution were proposed as a high performance sorbent for DNA isolation in batch fashion under equilibrium conditions. The proposed sorbent including both macroporous and mesoporous compartments was synthesized 5.1 μm in-size, by a "staged shape templated hydrolysis and condensation method". Hydrophilic polymer based sorbents were also obtained in the form of monodisperse-macroporous microspheres ca 5.5 μm in size, with different functionalities, by a developed "multi-stage microsuspension copolymerization" technique. The batch DNA isolation performance of proposed material was comparatively investigated using polymer based sorbents with similar morphologies. Among all sorbents tried, the best DNA isolation performance was achieved with the monodisperse silica microspheres with bimodal pore size distribution. The collocation of interconnected mesoporous and macroporous compartments within the monodisperse silica microspheres provided a high surface area and reduced the intraparticular mass transfer resistance and made easier both the adsorption and desorption of DNA. Among the polymer based sorbents, higher DNA isolation yields were achieved with the monodisperse-macroporous polymer microspheres carrying trimethoxysilyl and quaternary ammonium functionalities. However, batch DNA isolation performances of polymer based sorbents were significantly lower with respect to the silica microspheres.

  2. Synthesis of Monodispersed Gold Nanoparticles with Exceptional Colloidal Stability with Grafted Polyethylene Glycol-g-polyvinyl Alcohol

    Directory of Open Access Journals (Sweden)

    Alaaldin M. Alkilany

    2015-01-01

    Full Text Available Herein, we report the synthesis of spherical gold nanoparticles with tunable core size (23–79 nm in the presence of polyethylene glycol-g-polyvinyl alcohol (PEG-g-PVA grafted copolymer as a reducing, capping, and stabilizing agent in a one-step protocol. The resulted PEG-g-PVA-capped gold nanoparticles are monodispersed with an exceptional colloidal stability against salt addition, repeated centrifugation, and extensive dialysis. The effect of various synthesis parameters and the kinetic/mechanism of the nanoparticle formation are discussed.

  3. Impact electrochemistry on screen-printed electrodes for the detection of monodispersed silver nanoparticles of sizes 10-107 nm.

    Science.gov (United States)

    Nasir, Muhammad Zafir Mohamad; Pumera, Martin

    2016-10-12

    Impact electrochemistry provides a useful alternative technique for the detection of silver nanoparticles in solutions. The combined use of impact electrochemistry on screen-printed electrodes (SPEs) for the successful detection of silver nanoparticles provides an avenue for future on-site, point-of-care detection devices to be made for environmental, medicinal and biological uses. Here we discuss the use of screen-printed electrodes for the detection of well-defined monodispersed silver nanoparticles of sizes 10, 20, 40, 80, and 107 nm.

  4. Control of friction at the nanoscale

    Science.gov (United States)

    Barhen, Jacob; Braiman, Yehuda Y.; Protopopescu, Vladimir

    2010-04-06

    Methods and apparatus are described for control of friction at the nanoscale. A method of controlling frictional dynamics of a plurality of particles using non-Lipschitzian control includes determining an attribute of the plurality of particles; calculating an attribute deviation by subtracting the attribute of the plurality of particles from a target attribute; calculating a non-Lipschitzian feedback control term by raising the attribute deviation to a fractionary power .xi.=(2m+1)/(2n+1) where n=1, 2, 3 . . . and m=0, 1, 2, 3 . . . , with m strictly less than n and then multiplying by a control amplitude; and imposing the non-Lipschitzian feedback control term globally on each of the plurality of particles; imposing causes a subsequent magnitude of the attribute deviation to be reduced.

  5. Designing pseudocubic perovskites with enhanced nanoscale polarization

    Energy Technology Data Exchange (ETDEWEB)

    Levin, I. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Laws, W. J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Wang, D. [Department of Materials Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom; Reaney, I. M. [Department of Materials Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom

    2017-11-20

    A crystal-chemical framework has been proposed for the design of pseudocubic perovskites with nanoscale ferroelectric order, and its applicability has been demonstrated using a series of representative solid solutions that combined ferroelectric (K0.5Bi0.5TiO3, BaTiO3, and PbTiO3) and antiferroelectric (Nd-substituted BiFeO3) end members. The pseudocubic structures obtained in these systems exhibited distortions that were coherent on a scale ranging from sub-nanometer to tens of nanometers, but, in all cases, the macroscopic distortion remained unresolvable even if using high-resolution X-ray powder diffraction. Different coherence lengths for the local atomic displacements account for the distinctly different dielectric, ferroelectric, and electromechanical properties exhibited by the samples. The guidelines identified provide a rationale for chemically tuning the coherence length to obtain the desired functional response.

  6. Energy Conversion at Micro and Nanoscale

    International Nuclear Information System (INIS)

    Gammaitoni, Luca

    2014-01-01

    Energy management is considered a task of strategic importance in contemporary society. It is a common fact that the most successful economies of the planet are the economies that can transform and use large quantities of energy. In this talk we will discuss the role of energy with specific attention to the processes that happens at micro and nanoscale. The description of energy conversion processes at these scales requires approaches that go way beyond the standard equilibrium termodynamics of macroscopic systems. In this talk we will address from a fundamental point of view the physics of the dissipation of energy and will focus our attention to the energy transformation processes that take place in the modern micro and nano information and communication devices

  7. Nanoscale surface characterization using laser interference microscopy

    Science.gov (United States)

    Ignatyev, Pavel S.; Skrynnik, Andrey A.; Melnik, Yury A.

    2018-03-01

    Nanoscale surface characterization is one of the most significant parts of modern materials development and application. The modern microscopes are expensive and complicated tools, and its use for industrial tasks is limited due to laborious sample preparation, measurement procedures, and low operation speed. The laser modulation interference microscopy method (MIM) for real-time quantitative and qualitative analysis of glass, metals, ceramics, and various coatings has a spatial resolution of 0.1 nm for vertical and up to 100 nm for lateral. It is proposed as an alternative to traditional scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods. It is demonstrated that in the cases of roughness metrology for super smooth (Ra >1 nm) surfaces the application of a laser interference microscopy techniques is more optimal than conventional SEM and AFM. The comparison of semiconductor test structure for lateral dimensions measurements obtained with SEM and AFM and white light interferometer also demonstrates the advantages of MIM technique.

  8. Nanoscale device physics science and engineering fundamentals

    CERN Document Server

    Tiwari, Sandip

    2017-01-01

    Nanoscale devices are distinguishable from the larger microscale devices in their specific dependence on physical phenomena and effects that are central to their operation. The size change manifests itself through changes in importance of the phenomena and effects that become dominant and the changes in scale of underlying energetics and response. Examples of these include classical effects such as single electron effects, quantum effects such as the states accessible as well as their properties; ensemble effects ranging from consequences of the laws of numbers to changes in properties arising from different magnitudes of the inter-actions, and others. These interactions, with the limits placed on size, make not just electronic, but also magnetic, optical and mechanical behavior interesting, important and useful. Connecting these properties to the behavior of devices is the focus of this textbook. Description of the book series: This collection of four textbooks in the Electroscience series span the undergrad...

  9. Nanoscale spin sensing in artificial cell membranes

    International Nuclear Information System (INIS)

    Simpson David

    2014-01-01

    The use of the nitrogen-vacancy (NV) centre in diamond as a single spin sensor or magnetometer has attracted considerable interest in recent years because of its unique combination of sensitivity, nanoscale resolution, and optical initialisation and readout at room temperature. Nanodiamonds in particular hold great promise as an optical magnetometer probe for bio applications. In this work we employ nanodiamonds containing single NV spins to detect freely diffusing Mn2+ ions by detecting changes in the transverse relaxation time (T2) of the single spin probe. We also report the detection of gadolinium spin labels present in an artificial cell membrane by measuring changes in the longitudinal relaxation time (T1) of the probe. (author)

  10. Quantum Transport Simulations of Nanoscale Materials

    KAUST Repository

    Obodo, Tobechukwu Joshua

    2016-01-07

    Nanoscale materials have many potential advantages because of their quantum confinement, cost and producibility by low-temperature chemical methods. Advancement of theoretical methods as well as the availability of modern high-performance supercomputers allow us to control and exploit their microscopic properties at the atomic scale, hence making it possible to design novel nanoscale molecular devices with interesting features (e.g switches, rectifiers, negative differential conductance, and high magnetoresistance). In this thesis, state-of-the-art theoretical calculations have been performed for the quantum transport properties of nano-structured materials within the framework of Density Functional Theory (DFT) and the Nonequilibrium Green\\'s Function (NEGF) formalism. The switching behavior of a dithiolated phenylene-vinylene oligomer sandwiched between Au(111) electrodes is investigated. The molecule presents a configurational bistability, which can be exploited in constructing molecular memories, switches, and sensors. We find that protonation of the terminating thiol groups is at the origin of the change in conductance. H bonding at the thiol group weakens the S-Au bond, and thus lowers the conductance. Our results allow us to re-interpret the experimental data originally attributing the conductance reduction to H dissociation. Also examined is current-induced migration of atoms in nanoscale devices that plays an important role for device operation and breakdown. We studied the migration of adatoms and defects in graphene and carbon nanotubes under finite bias. We demonstrate that current-induced forces within DFT are non-conservative, which so far has only been shown for model systems, and can lower migration barrier heights. Further, we investigated the quantum transport behavior of an experimentally observed diblock molecule by varying the amounts of phenyl (donor) and pyrimidinyl (acceptor) rings under finite bias. We show that a tandem configuration of

  11. Nanoscale decomposition of Nb-Ru-O

    Science.gov (United States)

    Music, Denis; Geyer, Richard W.; Chen, Yen-Ting

    2016-11-01

    A correlative theoretical and experimental methodology has been employed to explore the decomposition of amorphous Nb-Ru-O at elevated temperatures. Density functional theory based molecular dynamics simulations reveal that amorphous Nb-Ru-O is structurally modified within 10 ps at 800 K giving rise to an increase in the planar metal - oxygen and metal - metal population and hence formation of large clusters, which signifies atomic segregation. The driving force for this atomic segregation process is 0.5 eV/atom. This is validated by diffraction experiments and transmission electron microscopy of sputter-synthesized Nb-Ru-O thin films. Room temperature samples are amorphous, while at 800 K nanoscale rutile RuO2 grains, self-organized in an amorphous Nb-O matrix, are observed, which is consistent with our theoretical predictions. This amorphous/crystalline interplay may be of importance for next generation of thermoelectric devices.

  12. Managing Temperature Effects in Nanoscale Adaptive Systems

    CERN Document Server

    Wolpert, David

    2012-01-01

    This book discusses new techniques for detecting, controlling, and exploiting the impacts of temperature variations on nanoscale circuits and systems.  It provides a holistic discussion of temperature management, including physical phenomena (reversal of the MOSFET temperature dependence) that have recently become problematic, along with circuit techniques for detecting, controlling, and adapting to these phenomena. A detailed discussion is also included of the general aspects of thermal-aware system design and management of temperature-induced faults. A new sensor system is described that can determine the temperature dependence as well as the operating temperature to improve system reliability.  A new method is presented to control a circuit’s temperature dependence by individually tuning pull-up and pull-down networks to their temperature-insensitive operating points. This method extends the range of supply voltages that can be made temperature-insensitive, achieving insensitivity at nominal voltage fo...

  13. System reduction for nanoscale IC design

    CERN Document Server

    2017-01-01

    This book describes the computational challenges posed by the progression toward nanoscale electronic devices and increasingly short design cycles in the microelectronics industry, and proposes methods of model reduction which facilitate circuit and device simulation for specific tasks in the design cycle. The goal is to develop and compare methods for system reduction in the design of high dimensional nanoelectronic ICs, and to test these methods in the practice of semiconductor development. Six chapters describe the challenges for numerical simulation of nanoelectronic circuits and suggest model reduction methods for constituting equations. These include linear and nonlinear differential equations tailored to circuit equations and drift diffusion equations for semiconductor devices. The performance of these methods is illustrated with numerical experiments using real-world data. Readers will benefit from an up-to-date overview of the latest model reduction methods in computational nanoelectronics.

  14. Transformative piezoelectric enhancement of P(VDF-TrFE) synergistically driven by nanoscale dimensional reduction and thermal treatment.

    Science.gov (United States)

    Ico, G; Myung, A; Kim, B S; Myung, N V; Nam, J

    2018-02-08

    Despite the significant potential of organic piezoelectric materials in the electro-mechanical or mechano-electrical applications that require light and flexible material properties, the intrinsically low piezoelectric performance as compared to traditional inorganic materials has limited their full utilization. In this study, we demonstrate that dimensional reduction of poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) at the nanoscale by electrospinning, combined with an appropriate thermal treatment, induces a transformative enhancement in piezoelectric performance. Specifically, the piezoelectric coefficient (d 33 ) reached up to -108 pm V -1 , approaching that of inorganic counterparts. Electrospun mats composed of thermo-treated 30 nm nanofibers with a thickness of 15 μm produced a consistent peak-to-peak voltage of 38.5 V and a power output of 74.1 μW at a strain of 0.26% while sustaining energy production over 10k repeated actuations. The exceptional piezoelectric performance was realized by the enhancement of piezoelectric dipole alignment and the materialization of flexoelectricity, both from the synergistic effects of dimensional reduction and thermal treatment. Our findings suggest that dimensionally controlled and thermally treated electrospun P(VDF-TrFE) nanofibers provide an opportunity to exploit their flexibility and durability for mechanically challenging applications while matching the piezoelectric performance of brittle, inorganic piezoelectric materials.

  15. Nanoscale Dewetting Transition in Protein Complex Folding

    Science.gov (United States)

    Hua, Lan; Huang, Xuhui; Liu, Pu; Zhou, Ruhong; Berne, Bruce J.

    2011-01-01

    In a previous study, a surprising drying transition was observed to take place inside the nanoscale hydrophobic channel in the tetramer of the protein melittin. The goal of this paper is to determine if there are other protein complexes capable of displaying a dewetting transition during their final stage of folding. We searched the entire protein data bank (PDB) for all possible candidates, including protein tetramers, dimers, and two-domain proteins, and then performed the molecular dynamics (MD) simulations on the top candidates identified by a simple hydrophobic scoring function based on aligned hydrophobic surface areas. Our large scale MD simulations found several more proteins, including three tetramers, six dimers, and two two-domain proteins, which display a nanoscale dewetting transition in their final stage of folding. Even though the scoring function alone is not sufficient (i.e., a high score is necessary but not sufficient) in identifying the dewetting candidates, it does provide useful insights into the features of complex interfaces needed for dewetting. All top candidates have two features in common: (1) large aligned (matched) hydrophobic areas between two corresponding surfaces, and (2) large connected hydrophobic areas on the same surface. We have also studied the effect on dewetting of different water models and different treatments of the long-range electrostatic interactions (cutoff vs PME), and found the dewetting phenomena is fairly robust. This work presents a few proteins other than melittin tetramer for further experimental studies of the role of dewetting in the end stages of protein folding. PMID:17608515

  16. Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, G.A.

    2009-09-14

    The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In

  17. Monodispersed fabrication and dielectric studies on ethylenediamine passivated α-manganese dioxide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, A. Martin [Research and Development Centre, Bharathiar University, Coimbatore, Tamilnadu (India); Kumar, R. Thilak, E-mail: manojthilak@yahoo.com [Periyar Arts College, Cuddalore-607001, Tamilnadu (India)

    2016-09-15

    Highlights: • Monodispersed ethylenediamine (EDA) passivated α-MnO{sub 2} nanorods were fabricated by inexpensive wet chemical method. • FTIR analysis indicated that surface passivation is strongly influenced by the introduction of the organic ligand. • XRD and HR-SEM revealed the structure and morphology of the fabricated α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. • Dielectric studies pointed out that the fabricated α-MnO{sub 2} is semiconducting in nature with resistivity, ρ = 1.46 to 5.76 × 10{sup 3} Ωcm. • The optical energy gap for the fabricated α-MnO{sub 2} nanorods is found to be around 1.37 eV. - Abstract: In this present work, pure α-MnO{sub 2} nanorods were fabricated by the reduction of 0.2 m/L of KMnO{sub 4} with 0.2 m/L of Na{sub 2}S{sub 2}O{sub 3}·5H{sub 2}O and by passivating with the organic ligand Ethylenediamine (EDA). The structural, functional, morphological and chemical composition of the nanorods were investigated by X-Ray Diffractometer (XRD), Fourier Transform Infrared Spectrometer (FTIR), High Resolution Scanning Electron Microscope (HR-SEM) and Energy Dispersive X-Ray Spectrometry (EDX). The XRD analysis indicated high crystalline nature of the product and FTIR confirmed the contribution of the organic ligand in surface passivation. HR-SEM image revealed the morphology of the α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. EDX confirmed the presence of Mn and O in the material. UV–visible spectrophotometery was used to determine the absorption behavior of the nanorods and an indirect band gap of 1.37 eV was acquired by Taucplot. Dielectric studies were carried out using Broadband Dielectric Spectrometer(BDS) and the resistivity was found to be around the semiconductor range (ρ = 1.46 to 5.76 × 10{sup 3} Ωcm).

  18. Inorganic biomaterials structure, properties and applications

    CERN Document Server

    Zhang, Xiang C

    2014-01-01

    This book provides a practical guide to the use and applications of inorganic biomaterials. It begins by introducing the concept of inorganic biomaterials, which includes bioceramics and bioglass. This concept is further extended to hybrid biomaterials consisting of inorganic and organic materials to mimic natural biomaterials. The book goes on to provide the reader with information on biocompatibility, bioactivity and bioresorbability. The concept of the latter is important because of the increasing role resorbable biomaterials are playing in implant applications. The book also introduces a n

  19. Inorganic elements in sugar samples

    Energy Technology Data Exchange (ETDEWEB)

    Salles, Paulo M.B. de; Campos, Tarcisio P.R. de, E-mail: pauladesalles@yahoo.com.br, E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Menezes, Maria Angela de B.C., E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Sugar is considered a safe food ingredient; however, it can be contaminated by organic elements since its planting until its production process. Thus, this study aims at checking the presence of inorganic elements in samples of crystal, refined and brown sugar available for consumption in Brazil. The applied technique was neutron activation analysis, the k{sub 0} method, using the TRIGA MARK - IPR-R1 reactor located at CDTN/CNEN, in Belo Horizonte. It was identified the presence of elements such as, Au, Br, Co, Cr, Hf, K, Na, Sb, Sc and Zn in the samples of crystal/refined sugar and the presence of As, Au, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Sb, Sc, Sm, Sr, Th and Zn in the brown sugar samples. The applied technique was appropriate to this study because it was not necessary to put the samples in solution, essential condition in order to apply other techniques, avoiding contaminations and sample losses, besides allowing a multi elementary detection in different sugar samples. (author)

  20. Inorganic elements in sugar samples

    International Nuclear Information System (INIS)

    Salles, Paulo M.B. de; Campos, Tarcisio P.R. de

    2013-01-01

    Sugar is considered a safe food ingredient; however, it can be contaminated by organic elements since its planting until its production process. Thus, this study aims at checking the presence of inorganic elements in samples of crystal, refined and brown sugar available for consumption in Brazil. The applied technique was neutron activation analysis, the k 0 method, using the TRIGA MARK - IPR-R1 reactor located at CDTN/CNEN, in Belo Horizonte. It was identified the presence of elements such as, Au, Br, Co, Cr, Hf, K, Na, Sb, Sc and Zn in the samples of crystal/refined sugar and the presence of As, Au, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Sb, Sc, Sm, Sr, Th and Zn in the brown sugar samples. The applied technique was appropriate to this study because it was not necessary to put the samples in solution, essential condition in order to apply other techniques, avoiding contaminations and sample losses, besides allowing a multi elementary detection in different sugar samples. (author)

  1. The quest for inorganic fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.; Ganteför, Gerd, E-mail: gerd.gantefoer@uni-konstanz.de, E-mail: ydkim91@skku.edu [Department of Physics, University of Konstanz, D-78457 Konstanz (Germany); Park, Eun Ji; Kim, Young Dok, E-mail: gerd.gantefoer@uni-konstanz.de, E-mail: ydkim91@skku.edu [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Seo, Hyun Ook [Center for Free-Electron Laser Science/DESY, D-22607 Hamburg (Germany); Idrobo, Juan-Carlos [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Pennycook, Stephen J. [Department of Materials Science and Engineering, National University of Singapore, Singapore 117575 (Singapore)

    2015-10-07

    Experimental results of the search for inorganic fullerenes are presented. Mo{sub n}S{sub m}{sup −} and W{sub n}S{sub m}{sup −} clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. The species in the first maximum at low mass are known to be platelets. Here, the structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy, and scanning tunneling microcopy. All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Accordingly, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.

  2. Inorganic chemically active adsorbents (ICAAs)

    Energy Technology Data Exchange (ETDEWEB)

    Ally, M.R. [Oak Ridge National Lab., TN (United States); Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  3. Preparation of monodisperse curcumin-imprinted polymer by precipitation polymerization and its application for the extraction of curcuminoids from Curcuma longa L.

    Science.gov (United States)

    Kitabatake, Tomoko; Tabo, Hiromi; Matsunaga, Hisami; Haginaka, Jun

    2013-08-01

    A monodisperse molecularly imprinted polymer (MIP) for curcumin was first prepared by precipitation polymerization using methacrylamide (MAM) and 4-vinylpyridine as functional co-monomers, divinylbenzene as a crosslinker, and a mixture of acetonitrile and toluene as a porogen. The use of MAM as the co-monomer resulted in the formation of a monodisperse MIP and non-imprinted polymer (NIP). MIP and NIP, respectively, were monodispersed with a narrow particle size distribution (3.3 ± 0.09 and 3.5 ± 0.10 μm). In addition to shape recognition, hydrophobic and hydrogen-bonding interactions affected the retention and molecular-recognition of curcumin on the MIP. The MIP for curcumin could extract curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) in Curcuma longa L.

  4. Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    H Nikukar

    2014-05-01

    We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis.  Keywords:  Mesenchymal, Nanoscale, Stem Cells.

  5. The Architectural Designs of a Nanoscale Computing Model

    Directory of Open Access Journals (Sweden)

    Mary M. Eshaghian-Wilner

    2004-08-01

    Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.

  6. Biomedical inorganic polymers bioactivity and applications of natural and synthetic polymeric inorganic molecules

    CERN Document Server

    Müller, Werner E G; Schröder, Heinz C; Schroder, Heinz C

    2014-01-01

    In recent years, inorganic polymers have attracted much attention in nano-biomedicine, in particular in the area of regenerative medicine and drug delivery. This growing interest in inorganic polymers has been further accelerated by the development of new synthetic and analytical methods in the field of nanotechnology and nanochemistry. Examples for biomedical inorganic polymers that had been proven to exhibit biomedical effects and/or have been applied in preclinical or clinical trials are polysilicate / silica glass (such as naturally formed "biosilica" and synthetic "bioglass") and inorganic polyphosphate. Some members of the mentioned biomedical inorganic polymers have already been applied e.g. as "bioglass" for bone repair and bone tissue engineering, or they are used in food processing and in dental care (inorganic polyphosphates). However, there are a number of further biological and medicinal properties of these polymers, which have been elucidated in the last few years but not yet been applied for tr...

  7. Integrative self-assembly of functional hybrid nanoconstructs by inorganic wrapping of single biomolecules, biomolecule arrays and organic supramolecular assemblies.

    Science.gov (United States)

    Patil, Avinash J; Li, Mei; Mann, Stephen

    2013-08-21

    Synthesis of functional hybrid nanoscale objects has been a core focus of the rapidly progressing field of nanomaterials science. In particular, there has been significant interest in the integration of evolutionally optimized biological systems such as proteins, DNA, virus particles and cells with functional inorganic building blocks to construct mesoscopic architectures and nanostructured materials. However, in many cases the fragile nature of the biomolecules seriously constrains their potential applications. As a consequence, there is an on-going quest for the development of novel strategies to modulate the thermal and chemical stabilities, and performance of biomolecules under adverse conditions. This feature article highlights new methods of "inorganic molecular wrapping" of single or multiple protein molecules, individual double-stranded DNA helices, lipid bilayer vesicles and self-assembled organic dye superstructures using inorganic building blocks to produce bio-inorganic nanoconstructs with core-shell type structures. We show that spatial isolation of the functional biological nanostructures as "armour-plated" enzyme molecules or polynucleotide strands not only maintains their intact structure and biochemical properties, but also enables the fabrication of novel hybrid nanomaterials for potential applications in diverse areas of bionanotechnology.

  8. Integrative self-assembly of functional hybrid nanoconstructs by inorganic wrapping of single biomolecules, biomolecule arrays and organic supramolecular assemblies

    Science.gov (United States)

    Patil, Avinash J.; Li, Mei; Mann, Stephen

    2013-07-01

    Synthesis of functional hybrid nanoscale objects has been a core focus of the rapidly progressing field of nanomaterials science. In particular, there has been significant interest in the integration of evolutionally optimized biological systems such as proteins, DNA, virus particles and cells with functional inorganic building blocks to construct mesoscopic architectures and nanostructured materials. However, in many cases the fragile nature of the biomolecules seriously constrains their potential applications. As a consequence, there is an on-going quest for the development of novel strategies to modulate the thermal and chemical stabilities, and performance of biomolecules under adverse conditions. This feature article highlights new methods of ``inorganic molecular wrapping'' of single or multiple protein molecules, individual double-stranded DNA helices, lipid bilayer vesicles and self-assembled organic dye superstructures using inorganic building blocks to produce bio-inorganic nanoconstructs with core-shell type structures. We show that spatial isolation of the functional biological nanostructures as ``armour-plated'' enzyme molecules or polynucleotide strands not only maintains their intact structure and biochemical properties, but also enables the fabrication of novel hybrid nanomaterials for potential applications in diverse areas of bionanotechnology.

  9. Room-temperature ductile inorganic semiconductor

    Science.gov (United States)

    Shi, Xun; Chen, Hongyi; Hao, Feng; Liu, Ruiheng; Wang, Tuo; Qiu, Pengfei; Burkhardt, Ulrich; Grin, Yuri; Chen, Lidong

    2018-05-01

    Ductility is common in metals and metal-based alloys, but is rarely observed in inorganic semiconductors and ceramic insulators. In particular, room-temperature ductile inorganic semiconductors were not known until now. Here, we report an inorganic α-Ag2S semiconductor that exhibits extraordinary metal-like ductility with high plastic deformation strains at room temperature. Analysis of the chemical bonding reveals systems of planes with relatively weak atomic interactions in the crystal structure. In combination with irregularly distributed silver-silver and sulfur-silver bonds due to the silver diffusion, they suppress the cleavage of the material, and thus result in unprecedented ductility. This work opens up the possibility of searching for ductile inorganic semiconductors/ceramics for flexible electronic devices.

  10. High surface area monodispersed Fe3O4 nanoparticles alone and on physical exfoliated graphite for improved supercapacitors

    Science.gov (United States)

    Sarno, Maria; Ponticorvo, Eleonora; Cirillo, Claudia

    2016-12-01

    Highly conductive, unsophisticated and easy to be obtained physical exfoliated graphite (PHG) supporting well dispersed magnetite, Fe3O4/PHG nanocomposite, has been prepared by a one-step chemical strategy and physico-chemical characterized. The nanocomposite, favoured by the a-polar nanoparticles (NPs) capping, results in a self-assembled monolayer of monodispersed Fe3O4, covering perfectly the hydrophobic surfaces of PHG. The nanocomposite as an electrode material was fabricated into a supercapacitor and characterized by cyclic voltammetry (CV) and galvanostatic charge-discharge measurements. It shows, after a suitable annealing, significant electrochemical properties (capacitance value of 787 F/g at 0.5 A g-1 and a Fe3O4/PHG weight ratio of 0.31) and good cycling stability (retention 91% after 30,000 cycles). Highly monodispersed very fine Fe3O4 NPs, covered by organic chains, have been also synthesized. The high surface area Fe3O4 NPs, after washing to leave a low content of organic chains able to avoid aggregation without excessively affecting the electrical properties of the material, exhibit remarkable pseudocapacitive activities, including the highest specific capacitance over reported for Fe3O4 (300 F/g at 0.5 A g-1).

  11. Seedless Synthesis of Monodispersed Gold Nanorods with Remarkably High Yield: Synergistic Effect of Template Modification and Growth Kinetics Regulation.

    Science.gov (United States)

    Liu, Kang; Bu, Yanru; Zheng, Yuanhui; Jiang, Xuchuan; Yu, Aibing; Wang, Huanting

    2017-03-08

    Gold nanorods (AuNRs) are versatile materials due to their broadly tunable optical properties associated with their anisotropic feature. Conventional seed-mediated synthesis is, however, not only limited by the operational complexity and over-sensitivity towards subtle changes of experimental conditions but also suffers from low yield (≈15 %). A facile seedless method is reported to overcome these challenges. Monodispersed AuNRs with high yield (≈100 %) and highly adjustable longitudinal surface plasmon resonance (LSPR) are reproducibly synthesized. The parameters that influence the AuNRs growth were thoroughly investigated in terms of growth kinetics and soft-template regulation, offering a better understanding of the template-based mechanism. The facile synthesis, broad tunability of LSRP, high reproducibility, high yield, and ease of scale-up make this method promising for the future mass production of monodispersed AuNRs for applications in catalysis, sensing, and biomedicine. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Response of three instruments devoted to surface-area for monodisperse and polydisperse aerosols in molecular and transition regimes

    International Nuclear Information System (INIS)

    Bau, Sebastien; Witschger, Olivier; Gensdarmes, Francois; Thomas, Dominique

    2011-01-01

    An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment. Indeed, our understanding of the hazards, the actual exposures in the workplace and the limits of engineering controls and personal protective equipment with regard to NP are still under development. Several studies have already identified surface-area as an important determinant of low solubility nanoparticles toxicity. As a consequence, the concept that surface-area could be a relevant metric for characterizing exposure to low solubility airborne NP has been proposed [1]. To provide NP surface-area concentration, some direct-reading instruments have been designed, based on diffusion charging. The actual available instruments providing airborne NP surface-area concentration are studied in this work: LQ1-DC (Matter Engineering), AeroTrak T M 9000 (TSI) and NSAM (TSI model 3550). Their performances regarding monodisperse carbon NP have been investigated by Bau et al.. This work aims at completing the instruments characterization regarding monodisperse NP of other chemical composition (aluminium, copper, silver) and studying their performances against polydisperse aerosols of NP.

  13. Facile preparation and visible light photocatalytic activity of CdIn2S4 monodispersed spherical particles

    International Nuclear Information System (INIS)

    Mu Jin; Wei Qinglian; Yao Pingping; Zhao Xueling; Kang Shizhao; Li Xiangqing

    2012-01-01

    Highlights: ► CdIn 2 S 4 monodispersed spherical particles were prepared by a soft solution method. ► Mercaptoacetic acid was used as capping agent to hinder the fast crystal growth. ► Thioacetamide as sulfur source resulted in the slow growth of particles. ► CdIn 2 S 4 spheres showed high visible light photocatalytic activity. - Abstract: We developed a facile method to prepare CdIn 2 S 4 monodispersed spherical particles by using mercaptoacetic acid as capping agent and thioacetamide as sulfur source. The results indicated that the size and morphology of CdIn 2 S 4 particles were related to reaction time. The CdIn 2 S 4 spherical particles with an average size of about 236 nm and a narrow size distribution were formed after reacting for 7 h. The photocatalytic activity of as-synthesized CdIn 2 S 4 spherical particles was evaluated by the photocatalytic degradation of methyl orange under visible light illumination. The results showed that the photocatalytic activity increased with prolonging reaction time in the preparation of CdIn 2 S 4 spherical particles. The CdIn 2 S 4 spherical particles prepared after reacting for 7 h exhibited a 98% degradation efficiency of methyl orange after 15 min visible light irradiation.

  14. Synthesis of monodisperse silica microspheres and modification with diazoresin for mixed-mode ultra high performance liquid chromatography separations.

    Science.gov (United States)

    Cong, Hailin; Yu, Bing; Tian, Chao; Zhang, Shuai; Yuan, Hua

    2017-11-01

    Monodisperse silica particles with average diameters of 1.9-2.9 μm were synthesized by a modified Stöber method, in which tetraethyl orthosilicate was continuously supplied to the reaction mixture containing KCl electrolyte, water, ethanol, and ammonia. The obtained silica particles were modified by self-assembly with positively charged photosensitive diazoresin on the surface. After treatment with ultraviolet light, the ionic bonding between silica and diazoresin was converted into covalent bonding through a unique photochemistry reaction of diazoresin. Depending on the chemical structure of diazoresin and mobile phase composition, the diazoresin-modified silica stationary phase showed different separation mechanisms, including reversed phase and hydrophilic interactions. Therefore, a variety of baseline separation of benzene analogues and organic acids was achieved by using the diazoresin-modified silica particles as packing materials in ultra high performance liquid chromatography. According to the π-π interactional difference between carbon rings of fullerenes and benzene rings of diazoresin, C 60 and C 70 were also well separated by ultra-high performance liquid chromatography. Because it has a small size, the ∼2.5 μm monodisperse diazoresin-modified silica stationary phase shows ultra-high efficiency compared with the commercial C 18 -silica high-performance liquid chromatography stationary phase with average diameters of ∼5 μm. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Arvind [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India); Singh, Vidya Nand; Mehta, Bodh Raj [Thin Film Laboratory, Department of Physics, Indian Institute of Technology, Delhi Hauz Khas, New Delhi 110016 (India); Khare, Sunil Kumar, E-mail: skhare@rocketmail.com [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

    2011-08-30

    Highlights: {yields} An efficient process wherein remediated manganese is synthesized into nanoparticles. {yields} A microbial process for manganese nanoparticle synthesis from metal waste streams. {yields} Nanoparticles characterized as monodispersed, spherical and 4.62 {+-} 0.14 nm sized MnO{sub 2}. -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 {+-} 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

  16. Microfluidic preparation and self diffusion PFG-NMR analysis of monodisperse water-in-oil-in-water double emulsions.

    Science.gov (United States)

    Hughes, Eric; Maan, Abid Aslam; Acquistapace, Simone; Burbidge, Adam; Johns, Michael L; Gunes, Deniz Z; Clausen, Pascal; Syrbe, Axel; Hugo, Julien; Schroen, Karin; Miralles, Vincent; Atkins, Tim; Gray, Richard; Homewood, Philip; Zick, Klaus

    2013-01-01

    Monodisperse water-in-oil-in-water (WOW) double emulsions have been prepared using microfluidic glass devices designed and built primarily from off the shelf components. The systems were easy to assemble and use. They were capable of producing double emulsions with an outer droplet size from 100 to 40 μm. Depending on how the devices were operated, double emulsions containing either single or multiple water droplets could be produced. Pulsed-field gradient self-diffusion NMR experiments have been performed on the monodisperse water-in-oil-in-water double emulsions to obtain information on the inner water droplet diameter and the distribution of the water in the different phases of the double emulsion. This has been achieved by applying regularization methods to the self-diffusion data. Using these methods the stability of the double emulsions to osmotic pressure imbalance has been followed by observing the change in the size of the inner water droplets over time. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Self-charging of 198Au-labeled monodisperse gold aerosols studied with a miniature electrical mobility spectrometer

    International Nuclear Information System (INIS)

    Yeh, H.C.; Newton, G.J.; Raabe, O.G.; Boor, D.R.

    1976-01-01

    Knowledge of the electrostatic character of an aerosol may be essential in assessing its potential inhalation hazard. In inhalation studies with radioactive aerosols, the aerosol charge state may change in the course of transport due to the emission of α, β or γ radiations. This paper describes an experimental study of the self-charging of 198 Au-labeled aerosols of monodisperse gold spheres by β emission. A miniature aerosol electrical mobility spectrometer, suitable for use in inhalation studies with radioactive aerosols, was developed and used in this study. This device is relatively inexpensive, easy to manufacture and its contamination by radioactive material has been minimized. Using polystyrene latex spheres, ranging in diameter from 0.176 to 1.18 μm, the spectrometer was calibrated with flow rates ranging from 400 to 4800 ml/min. Experiments with two sizes of 198 Au-labeled monodisperse gold aerosols were performed. Results indicate that the radioactivity of an aerosol can cause self-charging and affect the charge distribution. (author)

  18. Controllable synthesis and upconversion emission of ultrasmall near-monodisperse lanthanide-doped Sr2LaF7 nanocrystals

    International Nuclear Information System (INIS)

    Mao, Yifu; Ma, Mo; Gong, Lunjun; Xu, Changfu; Ren, Guozhong; Yang, Qibin

    2014-01-01

    Highlights: • Apropos NaOH content facilitates the growth of pure phase Sr 2 LaF 7 NCs. • Yb 3+ doping is favorable to the formation of Sr 2 LaF 7 NCs with uniform size. • Ultrasmall near-monodispersed Sr 2 LaF 7 NCs(sub-10 nm) were synthesized for the first time. • Intense multicolor upconversion can be obtained by properly lanthanide doping. - Abstract: Fluorite phase Sr 2 LaF 7 nanocrystals (NCs) were synthesized via solvothermal method using oleic acid as capping ligands. The effects of preparing conditions on the phase structure, crystal size, morphology, and upconversion (UC) emission properties of the products were studied. The results reveal that just apropos NaOH content facilitates the growth of near-monodispersed pure phase Sr 2 LaF 7 NCs, and Yb 3+ doping is favorable to the formation of pure Sr 2 LaF 7 phase with more uniform size distribution. The average crystalline size of the products can be controlled less than 10 nm. Following appropriate lanthanide ions doping, the NCs show intense blue, yellow, and white-color UC emission under the excitation of a 980 nm laser. The energy transfer UC mechanisms for the fluorescent intensity were also investigated

  19. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao; Dou, Jian; Chen, Luwei; Lin, Jianyi; Zeng, Hua Chun

    2012-01-01

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao

    2012-03-20

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

    International Nuclear Information System (INIS)

    Sinha, Arvind; Singh, Vidya Nand; Mehta, Bodh Raj; Khare, Sunil Kumar

    2011-01-01

    Highlights: → An efficient process wherein remediated manganese is synthesized into nanoparticles. → A microbial process for manganese nanoparticle synthesis from metal waste streams. → Nanoparticles characterized as monodispersed, spherical and 4.62 ± 0.14 nm sized MnO 2 . -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 ± 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

  2. Response of three instruments devoted to surface-area for monodisperse and polydisperse aerosols in molecular and transition regimes

    Energy Technology Data Exchange (ETDEWEB)

    Bau, Sebastien; Witschger, Olivier [Institut National de Recherche et de Securite (INRS), Laboratoire de Metrologie des Aerosols, Rue du Morvan, CS 60027, 54519 Vandoeuvre Cedex (France); Gensdarmes, Francois [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Physique et de Metrologie des Aerosols, BP 68, 91192 Gif-sur-Yvette (France); Thomas, Dominique, E-mail: sebastien.bau@inrs.fr [Laboratoire Reactions et Genie des Procedes (LRGP), groupe SAFE, 1 rue Grandville, BP 20041, 54001 Nancy Cedex (France)

    2011-07-06

    An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment. Indeed, our understanding of the hazards, the actual exposures in the workplace and the limits of engineering controls and personal protective equipment with regard to NP are still under development. Several studies have already identified surface-area as an important determinant of low solubility nanoparticles toxicity. As a consequence, the concept that surface-area could be a relevant metric for characterizing exposure to low solubility airborne NP has been proposed [1]. To provide NP surface-area concentration, some direct-reading instruments have been designed, based on diffusion charging. The actual available instruments providing airborne NP surface-area concentration are studied in this work: LQ1-DC (Matter Engineering), AeroTrak{sup TM} 9000 (TSI) and NSAM (TSI model 3550). Their performances regarding monodisperse carbon NP have been investigated by Bau et al.. This work aims at completing the instruments characterization regarding monodisperse NP of other chemical composition (aluminium, copper, silver) and studying their performances against polydisperse aerosols of NP.

  3. Inorganic nanolayers: structure, preparation, and biomedical applications.

    Science.gov (United States)

    Saifullah, Bullo; Hussein, Mohd Zobir B

    2015-01-01

    Hydrotalcite-like compounds are two-dimensional inorganic nanolayers also known as clay minerals or anionic clays or layered double hydroxides/layered hydroxy salts, and have emerged as a single type of material with numerous biomedical applications, such as drug delivery, gene delivery, cosmetics, and biosensing. Inorganic nanolayers are promising materials due to their fascinating properties, such as ease of preparation, ability to intercalate different type of anions (inorganic, organic, biomolecules, and even genes), high thermal stability, delivery of intercalated anions in a sustained manner, high biocompatibility, and easy biodegradation. Inorganic nanolayers have been the focus for researchers over the last decade, resulting in widening application horizons, especially in the field of biomedical science. These nanolayers have been widely applied in drug and gene delivery. They have also been applied in biosensing technology, and most recently in bioimaging science. The suitability of inorganic nanolayers for application in drug delivery, gene delivery, biosensing technology, and bioimaging science makes them ideal materials to be applied for theranostic purposes. In this paper, we review the structure, methods of preparation, and latest advances made by inorganic nanolayers in such biomedical applications as drug delivery, gene delivery, biosensing, and bioimaging.

  4. Salicylate-spectrophotometric determination of inorganic monochloramine

    International Nuclear Information System (INIS)

    Tao Hui; Chen Zhonglin; Li Xing; Yang Yanling; Li Guibai

    2008-01-01

    On the basis of classical Berthelot reaction, a simple salicylate-spectrophotometric method was developed for quantitative determination of inorganic monochloramine in water samples. With the catalysis of disodium pentacyanonitrosylferrate(III), inorganic monochloramine reacts with salicylate in equimolar to produce indophenol compound which has an intense absorption at 703 nm. Parameters that influence method performance, such as pH, dosage of salicylate and nitroprussiate and reaction time, were modified to enhance the method performance. By using this method, inorganic monochloramine can be distinguished from organic chloramines and other inorganic chlorine species, such as free chlorine, dichloramine, and trichloramine. The molar absorptivities of the final products formed by these compounds are below ±3% of inorganic monochloramine, because of the α-N in them have only one exchangeable hydrogen atom, and cannot react with salicylate to produce the indophenol compound. The upper concentrations of typical ions that do not interfere with the inorganic monochloramine determination are also tested to be much higher than that mostly encountered in actual water treatment. Case study demonstrates that the results obtained from this method are lower than DPD-titrimetric method because the organic chloramines formed by chlorination of organic nitrogenous compounds give no response in the newly established method. And the result measured by salicylate-spectrophotometric method is coincident with theoretical calculation

  5. Inorganic nanostructure-organic polymer heterostructures useful for thermoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    See, Kevin C.; Urban, Jeffrey J.; Segalman, Rachel A.; Coates, Nelson E.; Yee, Shannon K.

    2017-11-28

    The present invention provides for an inorganic nanostructure-organic polymer heterostructure, useful as a thermoelectric composite material, comprising (a) an inorganic nanostructure, and (b) an electrically conductive organic polymer disposed on the inorganic nanostructure. Both the inorganic nanostructure and the electrically conductive organic polymer are solution-processable.

  6. Methods for Introducing Inorganic Polymer Concepts throughout the Undergraduate Curriculum

    Science.gov (United States)

    de Lill, Daniel T.; Carraher, Charles E., Jr.

    2017-01-01

    Inorganic polymers can be introduced in a variety of undergraduate courses to discuss concepts related to polymer chemistry. Inorganic polymers such as silicates and polysiloxanes are simple materials that can be incorporated into an introductory or descriptive inorganic course. Polymers based on inorganic carbon, including diamond and graphite,…

  7. The synthesis and properties of nanoscale ionic materials

    KAUST Repository

    Rodriguez, Robert Salgado; Herrer, Rafael; Bourlinos, Athanasios B.; Li, Ruipeng; Amassian, Aram; Archer, Lynden A.; Giannelis, Emmanuel P.

    2010-01-01

    In this article we discuss the effect of constituents on structure, flow, and thermal properties of nanoscale ionic materials (NIMs). NIMs are a new class of nanohybrids consisting of a nanometer-sized core, a charged corona covalently attached

  8. Quantum dynamics in nanoscale magnets in dissipative environments

    NARCIS (Netherlands)

    Miyashita, S; Saito, K; Kobayashi, H.; de Raedt, H.A.

    2000-01-01

    In discrete energy structure of nanoscale magnets, nonadiabatic transitions at avoided level crossings lead to fundamental processes of dynamics of magnetizations. The thermal environment causes dissipative effects on these processes. In this paper we review the features of the nonadiabatic

  9. Democratization of Nanoscale Imaging and Sensing Tools Using Photonics.

    Science.gov (United States)

    McLeod, Euan; Wei, Qingshan; Ozcan, Aydogan

    2015-07-07

    Providing means for researchers and citizen scientists in the developing world to perform advanced measurements with nanoscale precision can help to accelerate the rate of discovery and invention as well as improve higher education and the training of the next generation of scientists and engineers worldwide. Here, we review some of the recent progress toward making optical nanoscale measurement tools more cost-effective, field-portable, and accessible to a significantly larger group of researchers and educators. We divide our review into two main sections: label-based nanoscale imaging and sensing tools, which primarily involve fluorescent approaches, and label-free nanoscale measurement tools, which include light scattering sensors, interferometric methods, photonic crystal sensors, and plasmonic sensors. For each of these areas, we have primarily focused on approaches that have either demonstrated operation outside of a traditional laboratory setting, including for example integration with mobile phones, or exhibited the potential for such operation in the near future.

  10. Dopant atoms as quantum components in silicon nanoscale devices

    Science.gov (United States)

    Zhao, Xiaosong; Han, Weihua; Wang, Hao; Ma, Liuhong; Li, Xiaoming; Zhang, Wang; Yan, Wei; Yang, Fuhua

    2018-06-01

    Recent progress in nanoscale fabrication allows many fundamental studies of the few dopant atoms in various semiconductor nanostructures. Since the size of nanoscale devices has touched the limit of the nature, a single dopant atom may dominate the performance of the device. Besides, the quantum computing considered as a future choice beyond Moore's law also utilizes dopant atoms as functional units. Therefore, the dopant atoms will play a significant role in the future novel nanoscale devices. This review focuses on the study of few dopant atoms as quantum components in silicon nanoscale device. The control of the number of dopant atoms and unique quantum transport characteristics induced by dopant atoms are presented. It can be predicted that the development of nanoelectronics based on dopant atoms will pave the way for new possibilities in quantum electronics. Project supported by National Key R&D Program of China (No. 2016YFA0200503).

  11. Abstractocyte: A Visual Tool for Exploring Nanoscale Astroglial Cells

    KAUST Repository

    Mohammed, Haneen

    2017-01-01

    This thesis presents the design and implementation of Abstractocyte, a system for the visual analysis of astrocytes, and their relation to neurons, in nanoscale volumes of brain tissue. Astrocytes are glial cells, i.e., non-neuronal cells

  12. Geometrical tuning of nanoscale split-ring resonators

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Kristensen, Anders; Xiao, Sanshui

    2010-01-01

    We investigate the capacitance tuning of nanoscale split-ring resonators. An LC-model predicts a simple dependence of resonance frequency on slit aspect ratio. Experimental and numerical data follow the predictions of the LC-model....

  13. Nanoscale Test Strips for Multiplexed Blood Analysis, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of our nanoscale test strips, or nanostrips, is to provide rapid, low-cost, powerful multiplexed analyses in a diminutive form so that whole body health...

  14. Interfacial and transport properties of nanoconstrained inorganic and organic materials

    Science.gov (United States)

    Kocherlakota, Lakshmi Suhasini

    Nanoscale constraints impact the material properties of both organic and inorganic systems. The systems specifically studied here are (i) nanoconstrained polymeric systems, poly(l-trimethylsilyl-1-propyne) (PTMSP) and poly(ethylene oxide) (PEO) relevant to gas separation membranes (ii) Zwitterionic polymers poly(sulfobetaine methacrylate)(pSBMA), poly(carboxybetaine acrylamide) (pCBAA), and poly(oligo(ethylene glycol) methyl methacrylate) (PEGMA) brushes critical for reducing bio-fouling (iii) Surface properties of N-layer graphene sheets. Interfacial constraints in ultrathin poly(l-trimethylsilyl-1-propyne) (PTMSP) membranes yielded gas permeabilities and CO2/helium selectivities that exceed bulk PTMSP membrane transport properties by up to three-fold for membranes of submicrometer thickness. Indicative of a free volume increase, a molecular energetic mobility analysis (involving intrinsic friction analysis) revealed enhanced methyl side group mobilities in thin PTMSP membranes with maximum permeation, compared to bulk films. Aging studies conducted over the timescales relevant to the conducted experiments signify that the free volume states in the thin film membranes are highly unstable in the presence of sorbing gases such as CO2. To maintain this high free volume configuration of polymer while improving the temporal stability an "inverse" architecture to conventional polymer nanocomposites was investigated, in which the polymer phase of PTMSP and PEO were interfacially and dimensionally constrained in nanoporous anodic aluminum oxide (AAO) membranes. While with this architecture the benefits of nanocomposite and ultrathin film membranes of PTMSP could be reproduced and improved upon, also the temporal stability could be enhanced substantially. The PEO-AAO nanocomposite membranes also revealed improved gas selectivity properties of CO2 over helium. In the thermal transition studies of zwitterionic pSBMA brushes a reversible critical transition temperature of 60

  15. Quantum Materials at the Nanoscale - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Stephen Lance [Univ. of Illinois, Urbana, IL (United States). Dept. of Physics

    2016-01-11

    The central aim of the Quantum Materials at the Nanoscale (QMN) cluster was to understand and control collective behavior involving the interplay of spins, orbitals, and charges, which governs many scientifically interesting and technologically important phenomena in numerous complex materials. Because these phenomena involve various competing interactions, and influence properties on many different length and energy scales in complex materials, tackling this important area of study motivated a collaborative effort that combined the diverse capabilities of QMN cluster experimentalists, the essential theoretical analysis provided by QMN cluster theorists, and the outstanding facilities and staff of the FSMRL. During the funding period 2007-2014, the DOE cluster grant for the Quantum Materials at the Nanoscale (QMN) cluster supported, at various times, 15 different faculty members (14 in Physics and 1 in Materials Science and Engineering), 7 postdoctoral research associates, and 57 physics and materials science PhD students. 41 of these PhD students have since graduated and have gone on to a variety of advanced technical positions at universities, industries, and national labs: 25 obtained postdoctoral positions at universities (14), industrial labs (2 at IBM), DOE national facilities (3 at Argonne National Laboratory, 1 at Brookhaven National Lab, 1 at Lawrence Berkeley National Lab, and 1 at Sandia National Lab), and other federal facilities (2 at NIST); 13 took various industrial positions, including positions at Intel (5), Quantum Design (1), Lasque Industries (1), Amazon (1), Bloomberg (1), and J.P. Morgan (1). Thus, the QMN grant provided the essential support for training a large number of technically advanced personnel who have now entered key national facilities, industries, and institutions. Additionally, during the period 2007-2015, the QMN cluster produced 159 publications (see pages 14-23), including 23 papers published in Physical Review Letters; 16

  16. Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rajendra Bordia

    2009-07-31

    The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and

  17. Single molecules and single nanoparticles as windows to the nanoscale

    Science.gov (United States)

    Caldarola, Martín; Orrit, Michel

    2018-05-01

    Since the first optical detection of single molecules, they have been used as nanometersized optical sensors to explore the physical properties of materials and light-matter interaction at the nanoscale. Understanding nanoscale properties of materials is fundamental for the development of new technology that requires precise control of atoms and molecules when the quantum nature of matter cannot be ignored. In the following lines, we illustrate this journey into nanoscience with some experiments from our group.

  18. Nanoscale volcanoes: accretion of matter at ion-sculpted nanopores.

    Science.gov (United States)

    Mitsui, Toshiyuki; Stein, Derek; Kim, Young-Rok; Hoogerheide, David; Golovchenko, J A

    2006-01-27

    We demonstrate the formation of nanoscale volcano-like structures induced by ion-beam irradiation of nanoscale pores in freestanding silicon nitride membranes. Accreted matter is delivered to the volcanoes from micrometer distances along the surface. Volcano formation accompanies nanopore shrinking and depends on geometrical factors and the presence of a conducting layer on the membrane's back surface. We argue that surface electric fields play an important role in accounting for the experimental observations.

  19. Self-assembled organic-inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles.

    Science.gov (United States)

    Denadai, Angelo M L; De Sousa, Frederico B; Passos, Joel J; Guatimosim, Fernando C; Barbosa, Kirla D; Burgos, Ana E; de Oliveira, Fernando Castro; da Silva, Jeann C; Neves, Bernardo R A; Mohallem, Nelcy D S; Sinisterra, Rubén D

    2012-01-01

    Organic-inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr(3+) and Cr(2)O(7) (2-) ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/βCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer-Emmett-Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn.

  20. Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

    Directory of Open Access Journals (Sweden)

    Ângelo M. L. Denadai

    2012-11-01

    Full Text Available Organic–inorganic magnetic hybrid materials (MHMs combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn were used as an adsorbent system for Cr3+ and Cr2O72− ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/βCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer–Emmett–Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions from aqueous solutions compared to that of Fe-Ni/Zn.

  1. Crystallisation and structural studies of monodisperse nylon oligomers and related polymers

    International Nuclear Information System (INIS)

    Sikorski, P.T.

    2001-11-01

    Using electron and X-ray diffraction data, together with computerised molecular modeling, the structures of monodisperse nylon oligomers and related polymers have been investigated. Structural changes on heating were also studied. The molecules were crystallised from solution and their morphologies examined using optical and transmission electron microscopy. Lath-like lamellar crystals of the polyester poly-β-propiolactone were crystallised isothermally. The interpretation of the diffraction data with the use of molecular modeling led to the discovery of the new crystalline structure, the γ-structure. In the γ-structure, the polyester chain is in an all-trans conformation and the structure consists of a two-chain, basal-faced, orthorhombic unit cell. The setting angles, with respect to the a axis, are ± 51.5 deg for the corner and centre chains, respectively. The lamellae are 5 nm in thickness and the chains run orthogonal to the lamellar surface. The general fold direction is along the a-axis (long axis of the crystal) and the chain folds successively in the [110] and [11-bar0] directions. Three different nylon 4 6 oligomers were crystallised from solution using a range of crystallisation methods. The 4- and 8-amide molecules were found to form three-dimensional crystals, in which the crystal thickness was much greater than the molecular length. The structure was found to be different from the nylon 4 6 polymer reported previously. It was found that the type of hydrogen-bonded sheet formed by these molecules can influence the way in which these sheets stack to form crystals. In addition, a study of the 9-amide molecule showed that a particular type of hydrogen-bonded sheet, a-sheet, is preferred for nylon 4 6. This discovery suggests that an amide unit is found in the fold in the chain-folded nylon 4 6 polymer crystals, to allow the a-sheets to be formed. It is not a consequence of a need to form a stress-free fold. In the regular adjacent re-entry chain

  2. Nanoscale tissue engineering: spatial control over cell-materials interactions

    Science.gov (United States)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G.; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two- and three-dimensional studies (2- and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. PMID:21451238

  3. Monolithic integration of nanoscale tensile specimens and MEMS structures

    International Nuclear Information System (INIS)

    Yilmaz, Mehmet; Kysar, Jeffrey W

    2013-01-01

    Nanoscale materials often have stochastic material properties due to a random distribution of material defects and an insufficient number of defects to ensure a consistent average mechanical response. Current methods to measure the mechanical properties employ MEMS-based actuators. The nanoscale specimens are typically mounted manually onto the load platform, so the boundary conditions have random variations, complicating the experimental measurement of the intrinsic stochasticity of the material properties. Here we show methods for monolithic integration of a nanoscale specimen co-fabricated with the loading platform. The nanoscale specimen is gold with dimensions of ∼40 nm thickness, 350 ± 50 nm width, and 7 μm length and the loading platform is an interdigitated electrode electrostatic actuator. The experiment is performed in a scanning electron microscope and digital image correlation is employed to measure displacements to determine stress and strain. The ultimate tensile strength of the nanocrystalline nanoscale specimen approaches 1 GPa, consistent with measurements made by other nanometer scale sample characterization methods on other material samples at the nanometer scale, as well as gold samples at the nanometer scale. The batch-compatible microfabrication method can be used to create nominally identical nanoscale specimens and boundary conditions for a broad range of materials. (paper)

  4. Nanoscale tissue engineering: spatial control over cell-materials interactions

    International Nuclear Information System (INIS)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Khademhosseini, Ali; Jabbari, Esmaiel

    2011-01-01

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment. (topical review)

  5. Hybrid Organic-Inorganic Bridged Silsesquioxane Nanoparticles for Cancer Nanomedicine

    KAUST Repository

    Fatieiev, Yevhen

    2017-10-01

    It is well established that cancer is one of the leading causes of death globally. Its complete eradication requires early detection and intensive drug treatment. In many cases it might also require surgery. Unfortunately, current medicine is still more focused on cancer treatment rather than elimination of its reason. The mechanism of tumor emergence and development is quite complicated, although, we are constantly advancing in this field. Nanomedicine is envisioned as the silver bullet against cancer. Thus, nanoscale systems with therapeutic and diagnostic modalities can simultaneously perform several functions: accurate detection of tumor site, precise targeting, and controlled drug release inside abnormal cells and tissues while being nontoxic to healthy ones. Moreover, surface modification of such nanoparticles allows them to be invisible to the immune system and have longer blood circulating time. The performed research in this dissertation is completely based on hybrid organicinorganic bridged silsesquioxane (also known as organosilica) nanomaterials, therefore comprising "soft" organic/bioorganic part which can imitate certain biorelevant structures and facilitates successful escape from the immune system for more efficient accumulation in cancer cells, while "hard" inorganic part serves as a rigid and stable basis for the creation of cargo nanocarriers and imaging agents. This dissertation discusses the 5 critical points of safe biodegradable nanoplatforms, delivery of large biomolecules, and cytotoxicity regarding the shape of nanoparticles. As a result novel fluorescent biodegradable oxamide-based organosilica nanoparticles were developed, light-triggered surface charge reversal for large biomolecule delivery was applied with hollow bridged silsesquioxane nanomaterials, and biocompatibility of periodic mesoporous organosilicas with different morphologies was studied. Furthermore, the current achievements and future perspectives of mesoporous silica

  6. Hybrid Organic-Inorganic Bridged Silsesquioxane Nanoparticles for Cancer Nanomedicine

    KAUST Repository

    Fatieiev, Yevhen

    2017-01-01

    It is well established that cancer is one of the leading causes of death globally. Its complete eradication requires early detection and intensive drug treatment. In many cases it might also require surgery. Unfortunately, current medicine is still more focused on cancer treatment rather than elimination of its reason. The mechanism of tumor emergence and development is quite complicated, although, we are constantly advancing in this field. Nanomedicine is envisioned as the silver bullet against cancer. Thus, nanoscale systems with therapeutic and diagnostic modalities can simultaneously perform several functions: accurate detection of tumor site, precise targeting, and controlled drug release inside abnormal cells and tissues while being nontoxic to healthy ones. Moreover, surface modification of such nanoparticles allows them to be invisible to the immune system and have longer blood circulating time. The performed research in this dissertation is completely based on hybrid organicinorganic bridged silsesquioxane (also known as organosilica) nanomaterials, therefore comprising "soft" organic/bioorganic part which can imitate certain biorelevant structures and facilitates successful escape from the immune system for more efficient accumulation in cancer cells, while "hard" inorganic part serves as a rigid and stable basis for the creation of cargo nanocarriers and imaging agents. This dissertation discusses the 5 critical points of safe biodegradable nanoplatforms, delivery of large biomolecules, and cytotoxicity regarding the shape of nanoparticles. As a result novel fluorescent biodegradable oxamide-based organosilica nanoparticles were developed, light-triggered surface charge reversal for large biomolecule delivery was applied with hollow bridged silsesquioxane nanomaterials, and biocompatibility of periodic mesoporous organosilicas with different morphologies was studied. Furthermore, the current achievements and future perspectives of mesoporous silica

  7. Isolation of nanoscale exosomes using viscoelastic effect

    Science.gov (United States)

    Hu, Guoqing; Liu, Chao

    2017-11-01

    Exosomes, molecular cargos secreted by almost all mammalian cells, are considered as promising biomarkers to identify many diseases including cancers. However, the small size of exosomes (30-200 nm) poses serious challenges on their isolation from the complex media containing a variety of extracellular vesicles (EVs) of different sizes, especially in small sample volumes. Here we develop a viscoelasticity-based microfluidic system to directly separate exosomes from cell culture media or serum in a continuous, size-dependent, and label-free manner. Using a small amount of biocompatible polymer as the additive into the media to control the viscoelastic forces exerted on EVs, we are able to achieve a high separation purity (>90%) and recovery (>80%) of exosomes. The size cutoff in viscoelasticity-based microfluidics can be easily controlled using different PEO concentrations. Based on this size-dependent viscoelastic separation strategy, we envision the handling of diverse nanoscale objects, such as gold nanoparticles, DNA origami structures, and quantum dots. This work was supported financially by National Natural Science Foundation of China (11572334, 91543125).

  8. Personalized Nanomedicine: A Revolution at the Nanoscale

    Directory of Open Access Journals (Sweden)

    Cristina Fornaguera

    2017-10-01

    Full Text Available Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines.

  9. Nanoscale Test Strips for Multiplexed Blood Analysis

    Science.gov (United States)

    Chan, Eugene

    2015-01-01

    A critical component of the DNA Medicine Institute's Reusable Handheld Electrolyte and Lab Technology for Humans (rHEALTH) sensor are nanoscale test strips, or nanostrips, that enable multiplexed blood analysis. Nanostrips are conceptually similar to the standard urinalysis test strip, but the strips are shrunk down a billionfold to the microscale. Each nanostrip can have several sensor pads that fluoresce in response to different targets in a sample. The strips carry identification tags that permit differentiation of a specific panel from hundreds of other nanostrip panels during a single measurement session. In Phase I of the project, the company fabricated, tested, and demonstrated functional parathyroid hormone and vitamin D nanostrips for bone metabolism, and thrombin aptamer and immunoglobulin G antibody nanostrips. In Phase II, numerous nanostrips were developed to address key space flight-based medical needs: assessment of bone metabolism, immune response, cardiac status, liver metabolism, and lipid profiles. This unique approach holds genuine promise for space-based portable biodiagnostics and for point-of-care (POC) health monitoring and diagnostics here on Earth.

  10. Surface Effects on Nanoscale Gas Flows

    Science.gov (United States)

    Beskok, Ali; Barisik, Murat

    2010-11-01

    3D MD simulations of linear Couette flow of argon gas confined within nano-scale channels are performed in the slip, transition and free molecular flow regimes. The velocity and density profiles show deviations from the kinetic theory based predictions in the near wall region that typically extends three molecular diameters (s) from each surface. Utilizing the Irwin-Kirkwood theorem, stress tensor components for argon gas confined in nano-channels are investigated. Outside the 3s region, three normal stress components are identical, and equal to pressure predicted using the ideal gas law, while the shear stress is a constant. Within the 3s region, the normal stresses become anisotropic and the shear stress shows deviations from its bulk value due to the surface virial effects. Utilizing the kinetic theory and MD predicted shear stress values, the tangential momentum accommodation coefficient for argon gas interacting with FCC structured walls (100) plane facing the fluid is calculated to be 0.75; this value is independent of the Knudsen number. Results show emergence of the 3s region as an additional characteristic length scale in nano-confined gas flows.

  11. Modeling Bloch oscillations in nanoscale Josephson junctions

    Science.gov (United States)

    Vora, Heli; Kautz, R. L.; Nam, S. W.; Aumentado, J.

    2018-01-01

    Bloch oscillations in nanoscale Josephson junctions with a Coulomb charging energy comparable to the Josephson coupling energy are explored within the context of a model previously considered by Geigenmüller and Schön that includes Zener tunneling and treats quasiparticle tunneling as an explicit shot-noise process. The dynamics of the junction quasicharge are investigated numerically using both Monte Carlo and ensemble approaches to calculate voltage-current characteristics in the presence of microwaves. We examine in detail the origin of harmonic and subharmonic Bloch steps at dc biases I = (n/m)2ef induced by microwaves of frequency f and consider the optimum parameters for the observation of harmonic (m = 1) steps. We also demonstrate that the GS model allows a detailed semiquantitative fit to experimental voltage-current characteristics previously obtained at the Chalmers University of Technology, confirming and strengthening the interpretation of the observed microwave-induced steps in terms of Bloch oscillations. PMID:29577106

  12. Personalized Nanomedicine: A Revolution at the Nanoscale

    Science.gov (United States)

    García-Celma, Maria José

    2017-01-01

    Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines. PMID:29023366

  13. Personalized Nanomedicine: A Revolution at the Nanoscale.

    Science.gov (United States)

    Fornaguera, Cristina; García-Celma, Maria José

    2017-10-12

    Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines.

  14. Nanomaterial Case Studies: Nanoscale Titanium Dioxide ...

    Science.gov (United States)

    This draft document presents two case studies of nanoscale titanium dioxide (nano-TiO2) used (1) to remove arsenic from drinking water and (2) as an active ingredient in topical sunscreen. The draft case studies are organized around a comprehensive environmental assessment approach that combines a product life cycle framework with the risk assessment paradigm. The document does not draw conclusions about potential risks. Rather, the case studies are intended to help identify what needs to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. This draft document is part of a process that will inform the development of EPA’s research strategy to support nanomaterial risk assessments. The complex properties of various nanomaterials make evaluating them in the abstract or with generalizations difficult if not impossible. Thus, this document focuses on two specific uses of nano-TiO2, as a drinking water treatment and as topical sunscreen. These case studies do not represent completed or even preliminary assessments; rather, they present the structure for identifying and prioritizing research needed to support future assessments.

  15. Foundation Coursework in Undergraduate Inorganic Chemistry: Results from a National Survey of Inorganic Chemistry Faculty

    Science.gov (United States)

    Raker, Jeffrey R.; Reisner, Barbara A.; Smith, Sheila R.; Stewart, Joanne L.; Crane, Johanna L.; Pesterfield, Les; Sobel, Sabrina G.

    2015-01-01

    A national survey of inorganic chemists explored the self-reported topics covered in foundation-level courses in inorganic chemistry at the postsecondary level; the American Chemical Society's Committee on Professional Training defines a foundation course as one at the conclusion of which, "a student should have mastered the vocabulary,…

  16. Toxicity of inhaled 238PuO2 in Beagle dogs: A. Monodisperse 1.5 μm AMAD particles. B. Monodisperse 3.0 μm particles. XV

    International Nuclear Information System (INIS)

    Mewhinney, J.A.; Gillett, N.A.; Muggenburg, B.A.; Hahn, F.F.; Diel, J.H.; Mauderly, J.L.; Boecker, B.B.; McClellan, R.O.

    1988-01-01

    Beagle dogs inhaled one of two sizes of monodisperse aerosols of 238 PuO 2 that resulted in graded levels of 238 Pu in the lung. All dogs are being studied for their life span. One hundred and thirty-seven dogs that had initial lung burdens ranging from 0.01 to 1.5 μCi 238 Pu/kg body weight (0.37 to 56 kBq/kg) have died, 8 with radiation pneumonitis and pulmonary fibrosis, 8 with lung tumors, 88 with bone tumors, 10 with liver tumors, and 25 of miscellaneous causes. Eighteen control dogs have died. Observations are being continued on 8 exposed and 6 control dogs alive at 4577-5274 days after exposure. (author)

  17. Toxicity of inhaled {sup 238}PuO{sub 2} in Beagle dogs: A. Monodisperse 1.5 {mu}m AMAD particles. B. Monodisperse 3.0 {mu}m particles. XV

    Energy Technology Data Exchange (ETDEWEB)

    Mewhinney, J A; Gillett, N A; Muggenburg, B A; Hahn, F F; Diel, J H; Mauderly, J L; Boecker, B B; McClellan, R O

    1988-12-01

    Beagle dogs inhaled one of two sizes of monodisperse aerosols of {sup 238}PuO{sub 2} that resulted in graded levels of {sup 238}Pu in the lung. All dogs are being studied for their life span. One hundred and thirty-seven dogs that had initial lung burdens ranging from 0.01 to 1.5 {mu}Ci {sup 238}Pu/kg body weight (0.37 to 56 kBq/kg) have died, 8 with radiation pneumonitis and pulmonary fibrosis, 8 with lung tumors, 88 with bone tumors, 10 with liver tumors, and 25 of miscellaneous causes. Eighteen control dogs have died. Observations are being continued on 8 exposed and 6 control dogs alive at 4577-5274 days after exposure. (author)

  18. Nanoscale Coloristic Pigments: Upper Limits on Releases from Pigmented Plastic during Environmental Aging, In Food Contact, and by Leaching

    DEFF Research Database (Denmark)

    Neubauer, Nicole; Scifo, Lorette; Navratilova, Jana

    2017-01-01

    The life cycle of nanoscale pigments in plastics may cause environmental or human exposure by various release scenarios. We investigated spontaneous and induced release with mechanical stress during/after simulated sunlight and rain degradation of polyethylene (PE) with organic and inorganic...... pigments. Additionally, primary leaching in food contact and secondary leaching from nanocomposite fragments with an increased surface into environmental media was examined. Standardized protocols/methods for release sampling, detection, and characterization of release rate and form were applied......: Transformation of the bulk material was analyzed by Scanning Electron Microscopy (SEM), X-ray-tomography and Fourier-Transform Infrared spectroscopy (FTIR); releases were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), single-particle-ICP-MS (sp-ICP-MS), Transmission Electron Microscopy (TEM...

  19. Influence of the vibration source location on the modes of jet disintegration in the priller and on monodispersity of the finished product

    OpenAIRE

    Skydanenko, Maksym; Kononenko, Mykola; Kurdes, Yuliia

    2017-01-01

    Influence of the vibration source location on the modes of liquid jets disintegration and obtaining monodisperse droplets and granules of the finished product is theoretically grounded and experimentally confirmed. The experiment was conducted on an experimental stand of industrial granulation equipment.

  20. Monodisperse Water-in-Oil-in-Water (W/O/W Double Emulsion Droplets as Uniform Compartments for High-Throughput Analysis via Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Jing Yan

    2013-12-01

    Full Text Available Here we report the application of monodisperse double emulsion droplets, produced in a single step within partially hydrophilic/partially hydrophobic microfluidic devices, as defined containers for quantitative flow cytometric analysis. Samples with varying fluorophore concentrations were generated, and a clear correlation between dye concentration and fluorescence signals was observed.

  1. Synthesis and Magnetic Properties of Nearly Monodisperse CoFe2O4Nanoparticles Through a Simple Hydrothermal Condition

    Directory of Open Access Journals (Sweden)

    Li Xing-Hua

    2010-01-01

    Full Text Available Abstract Nearly monodisperse cobalt ferrite (CoFe2O4 nanoparticles without any size-selection process have been prepared through an alluring method in an oleylamine/ethanol/water system. Well-defined nanospheres with an average size of 5.5 nm have been synthesized using metal chloride as the law materials and oleic amine as the capping agent, through a general liquid–solid-solution (LSS process. Magnetic measurement indicates that the particles exhibit a very high coercivity at 10 K and perform superparamagnetism at room temperature which is further illuminated by ZFC/FC curves. These superparamagnetic cobalt ferrite nanomaterials are considered to have potential application in the fields of biomedicine. The synthesis method is possible to be a general approach for the preparation of other pure binary and ternary compounds.

  2. Preparation of size-tunable, highly monodisperse PVP-protected Pt-nanoparticles by seed-mediated growth

    International Nuclear Information System (INIS)

    Koebel, Matthias M.; Jones, Louis C.; Somorjai, Gabor A.

    2008-01-01

    We demonstrate a preparative method which produces highly monodisperse Pt-nanoparticles of tunable size without the external addition of seed particles. Hexachloroplatinic acid is dosed slowly to an ethylene glycol solution at 120 o C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrrolidone (PVP). Slow addition of the Pt-salt will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8 nm. The amount of added hexachloroplatinic acid precursor controls the size of the final nanoparticle product. TEM was used to determine size and morphology and to confirm the crystalline nature of the nanoparticles. Good reproducibility of the technique was demonstrated. Above 7 nm, the particle shape and morphology changes suddenly indicating a change in the deposition selectivity of the Pt-precursor from (100) towards (111) crystal faces and breaking up of larger particles into smaller entities.

  3. Facile preparation of monodisperse, impurity-free, and antioxidation copper nanoparticles on a large scale for application in conductive ink.

    Science.gov (United States)

    Zhang, Yu; Zhu, Pengli; Li, Gang; Zhao, Tao; Fu, Xianzhu; Sun, Rong; Zhou, Feng; Wong, Ching-ping

    2014-01-08

    Monodisperse copper nanoparticles with high purity and antioxidation properties are synthesized quickly (only 5 min) on a large scale (multigram amounts) by a modified polyol process using slightly soluble Cu(OH)2 as the precursor, L-ascorbic acid as the reductant, and PEG-2000 as the protectant. The resulting copper nanoparticles have a size distribution of 135 ± 30 nm and do not suffer significant oxidation even after being stored for 30 days under ambient conditions. The copper nanoparticles can be well-dispersed in an oil-based ink, which can be silk-screen printed onto flexible substrates and then converted into conductive patterns after heat treatment. An optimal electrical resistivity of 15.8 μΩ cm is achieved, which is only 10 times larger than that of bulk copper. The synthesized copper nanoparticles could be considered as a cheap and effective material for printed electronics.

  4. Direct electron transfer of Cytochrome c at mono-dispersed and negatively charged perylene-graphene matrix.

    Science.gov (United States)

    Zhang, Nan; Lv, Xiangyu; Ma, Weiguang; Hu, Yuwei; Li, Fenghua; Han, Dongxue; Niu, Li

    2013-03-30

    Mono-dispersed 3,4,9,10-perylene tetracarboxylic acid (PTCA) functionalized graphene sheets (PTCA-graphene) were fabricated by a chemical route and dispersed well in aqueous solution. PTCA-graphene with plenty of -COOH groups as electrostatic absorbing sites were beneficial to the loading of Cytochrome c (Cyt c). Cyt c, which was tightly immobilized on the PTCA-graphene modified glassy carbon electrode, maintained its natural conformation. Direct electron transfer of Cyt c and the electro-catalytic activity towards the reduction of H2O2 were also achieved. It has been substantiated that PTCA-graphene is a preferable biocompatible matrix for Cyt c. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. NOx formation from the combustion of monodisperse n-heptane sprays doped with fuel-nitrogen additives

    Science.gov (United States)

    Sarv, Hamid; Cernansky, Nicholas P.

    1989-01-01

    A series of experiments with simulated synthetic fuels were conducted in order to investigate the effect of droplet size on the conversion of fuel-nitrogen to NOx. Pyridine and pyrrole were added to n-heptane as nitrogen-containing additives and burned as monodisperse fuel droplets under various operating conditions in a spray combustion facility. The experimental results indicate that under stoichiometric and fuel-rich conditions, reducing the droplet size increases the efficiency of fuel-N conversion to NOx. This observation is associated with improved oxidation of the pyrolysis fragments of the additive by better oxygen penetration through the droplet flame zone. The dominant reactions by which fuel-N is transformed to NOx were also considered analytically by a premixed laminar flame code. The calculations are compared to the small droplet size results.

  6. Preparation of submicrometer monodispersed magnetic silica particles using a novel water in oil microemulsion: properties and application for enzyme immobilization.

    Science.gov (United States)

    Tuttolomondo, Maria Victoria; Villanueva, Maria Emilia; Alvarez, Gisela Solange; Desimone, Martín Federico; Díaz, Luis Eduardo

    2013-10-01

    The synthesis of monodispersed magnetic silica nanoparticles (MSN) is described using a water-in-oil reverse microemulsion system that does not require the use of co-surfactants. Sodium silicate, Tween 20 as a neutral surfactant and 1-butanol as the organic phase were used. There are several advantages of the proposed method including a saturation magnetization value of 10 emu/g for the particles obtained, uniformity of size and that they are easily functionalized to bind urease covalently. Moreover, the intra-day, inter-day and long-term stability results confirm that the procedure was successful and the enzyme-linked MSNs were stable over repeated uses and storage retaining more than 75% activity after 4 months.

  7. Intercalation compounds involving inorganic layered structures

    Directory of Open Access Journals (Sweden)

    CONSTANTINO VERA R. L.

    2000-01-01

    Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

  8. Industrial inorganic chemistry. 2. rev. ed.

    International Nuclear Information System (INIS)

    Buechner, W.; Schliebs, R.; Winter, G.; Buechel, K.H.

    1986-01-01

    Inorganic chemistry is a branch of considerable economic and technical importance. Apart from supplying the market with metals, fertilizers, building materials, pigments and glass it is one of the major suppliers of process materials to the organic chemical industry. Many modern products of other industrial sectors (video tapes, optical fibers or silicon chips) could not have been developed and manufactured without the achievements of industrial inorganic chemistry. The publication is the first of its kind to give a compact description of the inorganic chemistry sector. A clearly arranged survey facilitates access to production processes, economic aspects, ecological implications, energy consumption and raw material consumption as well as to many other data and facts. Due to its clear arrangement and the combination of technical and economic facts the book is a valuable source of information. (orig./EF) [de

  9. Inorganic Nanoparticles for Multimodal Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Magdalena Swierczewska

    2011-01-01

    Full Text Available Multimodal molecular imaging can offer a synergistic improvement of diagnostic ability over a single imaging modality. Recent development of hybrid imaging systems has profoundly impacted the pool of available multimodal imaging probes. In particular, much interest has been focused on biocompatible, inorganic nanoparticle-based multimodal probes. Inorganic nanoparticles offer exceptional advantages to the field of multimodal imaging owing to their unique characteristics, such as nanometer dimensions, tunable imaging properties, and multifunctionality. Nanoparticles mainly based on iron oxide, quantum dots, gold, and silica have been applied to various imaging modalities to characterize and image specific biologic processes on a molecular level. A combination of nanoparticles and other materials such as biomolecules, polymers, and radiometals continue to increase functionality for in vivo multimodal imaging and therapeutic agents. In this review, we discuss the unique concepts, characteristics, and applications of the various multimodal imaging probes based on inorganic nanoparticles.

  10. Inorganic matter characterization in vegetable biomass feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Garcia, F.; Martinez-Alonso, A.; Fernandez Llorenta, M.; Tascon, J.M.D. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2002-06-01

    A combination of techniques was used to characterize the inorganic constituents of four types of vegetable biomass: apple pulp, olive cake, olive tree pruning and thistle. Two methods were used to selectively eliminate organic matter: low-temperature oxidation in an oxygen plasma, and medium-temperature oxidation in air. Inorganic species present in the residues were identified by X-ray diffraction and FT-IR spectroscopy. The combination of these techniques allowed one to detect SiO{sub 2}, CaCO{sub 3} and various other Ca-, Mg-, Na- and K-containing phases as inorganic constituents of the studied biomass residues. It is concluded that the oxygen plasma treatment produces sulphates and nitrates that were not present in the starting material. Medium-temperature oxidation does not produce these artificial species but induces some thermal transformations in the mineral constituents of biomass, so that each technique has its own advantages and disadvantages. 27 refs., 6 figs., 3 tabs.

  11. Rapid Synthesis of Highly Monodisperse Au x Ag 1− x Alloy Nanoparticles via a Half-Seeding Approach

    KAUST Repository

    Chng, Ting Ting

    2011-05-03

    Gold-silver alloy AuxAg1-x is an important class of functional materials promising new applications across a wide array of technological fields. In this paper, we report a fast and facile synthetic protocol for preparation of highly monodisperse AuxAg1-x alloy nanoparticles in the size range of 3-6 nm. The precursors employed in this work are M(I)-alkanethiolates (M = Au and Ag), which can be easily prepared by mixing common chemicals such as HAuCl4 or AgNO3 with alkanethiols at room temperature. In this half-seeding approach, one of the M(I)-alkanethiolates is first heated and reduced in oleylamine solvent, and freshly formed metal clusters will then act as premature seeds on which both the first and second metals (from M(I)-alkanethiolates, M = Au and Ag) can grow accordingly without additional nucleation and thus achieve high monodispersity for product alloy nanoparticles. Unlike in other prevailing methods, both Au and Ag elements present in these solid precursors are in the same monovalent state and have identical supramolecular structures, which may lead to a more homogeneous reduction and complete interdiffusion at elevated reaction temperatures. When the M(I)-alkanethiolates are reduced to metallic forms, the detached alkanethiolate ligands will serve as capping agent to control the growth. More importantly, composition, particle size, and optical properties of AuxAg1-x alloy nanoparticles can be conveniently tuned with this approach. The optical limiting properties of the prepared particles have also been investigated at 532 and 1064 nm using 7 ns laser pulses, which reveals that the as-prepared alloy nanoparticles exhibit outstanding broadband optical limiting properties with low thresholds. © 2011 American Chemical Society.

  12. Synthesis and characterization of monodisperse, mesoporous, and magnetic sub-micron particles doped with a near-infrared fluorescent dye

    International Nuclear Information System (INIS)

    Le Guevel, Xavier; Nooney, Robert; McDonagh, Colette; MacCraith, Brian D.

    2011-01-01

    Recently, multifunctional silica nanoparticles have been investigated extensively for their potential use in biomedical applications. We have prepared sub-micron monodisperse and stable multifunctional mesoporous silica particles with a high level of magnetization and fluorescence in the near infrared region using an one-pot synthesis technique. Commercial magnetite nanocrystals and a conjugated-NIR-dye were incorporated inside the particles during the silica condensation reaction. The particles were then coated with polyethyleneglycol to stop aggregation. X-ray diffraction, N 2 adsorption analysis, TEM, fluorescence and absorbance measurements were used to structurally characterize the particles. These mesoporous silica spheres have a large surface area (1978 m 2 /g) with 3.40 nm pore diameter and a high fluorescence in the near infrared region at λ=700 nm. To explore the potential of these particles for drug delivery applications, the pore accessibility to hydrophobic drugs was simulated by successfully trapping a hydrophobic ruthenium dye complex inside the particle with an estimated concentration of 3 wt%. Fluorescence imaging confirmed the presence of both NIR dye and the post-grafted ruthenium dye complex inside the particles. These particles moved at approximately 150 μm/s under the influence of a magnetic field, hence demonstrating the multifunctionality and potential for biomedical applications in targeting and imaging. - Graphical Abstract: Hydrophobic fluorescent Ruthenium complex has been loaded into the mesopores as a surrogate drug to simulate drug delivery and to enhance the multifunctionality of the magnetic NIR emitting particles. Highlights: → Monodisperse magnetic mesoporous silica particles emitting in the near infrared region are obtained in one-pot synthesis. → We prove the capacity of such particles to uptake hydrophobic dye to mimic drug loading. → Loaded fluorescent particles can be moved under a magnetic field in a microfluidic

  13. Nanoscale Metal Oxide Semiconductors for Gas Sensing

    Science.gov (United States)

    Hunter, Gary W.; Evans, Laura; Xu, Jennifer C.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.

    2011-01-01

    A report describes the fabrication and testing of nanoscale metal oxide semiconductors (MOSs) for gas and chemical sensing. This document examines the relationship between processing approaches and resulting sensor behavior. This is a core question related to a range of applications of nanotechnology and a number of different synthesis methods are discussed: thermal evaporation- condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed, providing a processing overview to developers of nanotechnology- based systems. The results of a significant amount of testing and comparison are also described. A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. The TECsynthesized single-crystal nanowires offer uniform crystal surfaces, resistance to sintering, and their synthesis may be done apart from the substrate. The TECproduced nanowire response is very low, even at the operating temperature of 200 C. In contrast, the electrospun polycrystalline nanofiber response is high, suggesting that junction potentials are superior to a continuous surface depletion layer as a transduction mechanism for chemisorption. Using a catalyst deposited upon the surface in the form of nanoparticles yields dramatic gains in sensitivity for both nanostructured, one-dimensional forms. For the nanowire materials, the response magnitude and response rate uniformly increase with increasing operating temperature. Such changes are interpreted in terms of accelerated surface diffusional processes, yielding greater access to chemisorbed oxygen species and faster dissociative chemisorption, respectively. Regardless of operating temperature, sensitivity of the nanofibers is a factor of 10 to 100 greater than that of nanowires with the same catalyst for the same test condition. In summary, nanostructure appears critical to governing the reactivity, as measured by electrical

  14. Engineered inorganic core/shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mélinon, Patrice, E-mail: patrice.melinon@univ-lyon1.fr [Institut Lumière matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Léon Brillouin, 43 Boulevard du 11 Novembre 1918, F 69622 Villeurbanne (France); Begin-Colin, Sylvie [IPCMS et OMNT, 23 rue du Loess BP 43, 67034 STRASBOURG Cedex 2 (France); Duvail, Jean Luc [IMN UMR 6502 et OMNT Campus Sciences : 2 rue de la Houssinire, BP32229, 44322 Nantes Cedex3 (France); Gauffre, Fabienne [SPM et OMNT : Institut des sciences chimiques de Rennes - UMR 6226, 263 Avenue du General Leclerc, CS 74205, 35042 RENNES Cedex (France); Boime, Nathalie Herlin [IRAMIS-NIMBE, Laboratoire Francis Perrin (CEA CNRS URA 2453) et OMNT, Bat 522, CEA Saclay, 91191 Gif sur Yvette Cedex (France); Ledoux, Gilles [Institut Lumière Matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Alfred Kastler 43 Boulevard du 11 Novembre 1918 F 69622 Villeurbanne (France); Plain, Jérôme [Universit de technologie de Troyes LNIO-ICD, CNRS et OMNT 12 rue Marie Curie - CS 42060 - 10004 Troyes cedex (France); Reiss, Peter [CEA Grenoble, INAC-SPrAM, UMR 5819 CEA-CNRS-UJF et OMNT, Grenoble cedex 9 (France); Silly, Fabien [CEA, IRAMIS, SPEC, TITANS, CNRS 2464 et OMNT, F-91191 Gif sur Yvette (France); Warot-Fonrose, Bénédicte [CEMES-CNRS, Université de Toulouse et OMNT, 29 rue Jeanne Marvig F 31055 Toulouse (France)

    2014-10-20

    It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

  15. Near-infrared light-responsive inorganic nanomaterials for photothermal therapy

    Directory of Open Access Journals (Sweden)

    Zhihong Bao

    2016-06-01

    Full Text Available Novel nanomaterials and advanced nanotechnologies prompt the fast development of new protocols for biomedical application. The unique light-to-heat conversion property of nanoscale materials can be utilized to produce novel and effective therapeutics for cancer treatment. In particular, near-infrared (NIR photothermal therapy (PTT has gained popularity and very quickly developed in recent years due to minimally invasive treatments for patients. This review summarizes the current state-of-the-art in the development of inorganic nanocomposites for photothermal cancer therapy. The current states of the design, synthesis, the cellular uptake behavior, the cellular cytotoxicity and both in vivo and in vitro nanoparticle assisted photothermal treatments of inorganic photothermal therapy agents (PTA are described. Finally, the perspective and challenges of PTT development are presented and some proposals are suggested for its further development and exploration. This summary should provide improved understanding of cancer treatment with photothermal nanomaterials and push nanoscience and nanotechnology one step at a time toward clinical applications.

  16. Development of Inorganic Solar Cells by Nanotechnology

    Institute of Scientific and Technical Information of China (English)

    Yafei Zhang; Huijuan Geng; Zhihua Zhou; Jiang Wu; Zhiming Wang; Yaozhong Zhang; Zhongli Li; Liying Zhang; Zhi Yang; Huey Liang Hwang

    2012-01-01

    Inorganic solar cells, as durable photovoltaic devices for harvesting electric energy from sun light,have received tremendous attention due to the fear of exhausting the earth’s energy resources and damaging the living environment due to greenhouse gases. Some recent developments in nanotechnology have opened up new avenues for more relevant inorganic solar cells produced by new photovoltaic conversion concepts and effective solar energy harvesting nanostructures. In this review, the multiple exciton generation effect solar cells, hot carrier solar cells, one dimensional material constructed asymmetrical schottky barrier arrays, noble nanoparticle induced plasmonic enhancement, and light trapping nanostructured semiconductor solar cells are highlighted.

  17. Separation of fission products using inorganic exchangers

    International Nuclear Information System (INIS)

    Murthy, T.S.; Balasubramanian, K.R.; Rao, K.L.N.; Venkatachalam, R.; Varma, R.N.

    1981-01-01

    This paper describes the separation of long lived fission products like caesium-137, strontium-90 using inorganic exchangers ammonium phosphomolybdate and zirconium antimonate. A revised flow sheet is proposed for the sequential separation of these isotopes using the above two compounds. This is a modification of the earlier scheme developed which involved the use of four inorganic exchangers namely ammonium phosphomolybdate, manganese dioxide, zirconium antimonate and polyantimonic acid. The elution of the adsorbed elements like cerium, strontium, and sodium has been studied and it has been possible to elute these using different eluting agents. (author)

  18. Chronic inorganic mercury induced peripheral neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Chu, C.-C.; Huang, C.-C.; Ryu, S.-J. [Chang Gung Memorial Hospital and Chang Gung University, Dept. of Neurology, Tapei (Taiwan, Province of China); Wu, T.-N. [Executive Yuan, Dept. of Health, Surveillance and Quarantine Service, Taipei (Taiwan, Province of China)

    1998-12-01

    We report the clinical features, electrophysiological studies, and morphometric analysis of sural nerve pathology in a patient with polyneuropathy due to inorganic mercury intoxication. He developed slowly progressive generalized paralysis of all limbs after 3 months ingestion of herb drugs which contained mercuric sulfate. Electrophysiologic studies revealed axonal polyneuropathy involving both motor and sensory fibers. Sural nerve biopsy demonstrated axonal degeneration with demyelination and a predominant loss of large myelinated fibers. His muscle strength showed only mild improvement after 2 years` follow-up. We concluded that inorganic mercury exposure may induce severe axonal sensorimotor polyneuropathy in humans and that neurological deficits may persist in severe cases. (au) 21 refs.

  19. Impact of nanoscale topography on genomics and proteomics of adherent bacteria.

    Science.gov (United States)

    Rizzello, Loris; Sorce, Barbara; Sabella, Stefania; Vecchio, Giuseppe; Galeone, Antonio; Brunetti, Virgilio; Cingolani, Roberto; Pompa, Pier Paolo

    2011-03-22

    Bacterial adhesion onto inorganic/nanoengineered surfaces is a key issue in biotechnology and medicine, because it is one of the first necessary steps to determine a general pathogenic event. Understanding the molecular mechanisms of bacteria-surface interaction represents a milestone for planning a new generation of devices with unanimously certified antibacterial characteristics. Here, we show how highly controlled nanostructured substrates impact the bacterial behavior in terms of morphological, genomic, and proteomic response. We observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that type-1 fimbriae typically disappear in Escherichia coli adherent onto nanostructured substrates, as opposed to bacteria onto reference glass or flat gold surfaces. A genetic variation of the fimbrial operon regulation was consistently identified by real time qPCR in bacteria interacting with the nanorough substrates. To gain a deeper insight into the molecular basis of the interaction mechanisms, we explored the entire proteomic profile of E. coli by 2D-DIGE, finding significant changes in the bacteria adherent onto the nanorough substrates, such as regulations of proteins involved in stress processes and defense mechanisms. We thus demonstrated that a pure physical stimulus, that is, a nanoscale variation of surface topography, may play per se a significant role in determining the morphological, genetic, and proteomic profile of bacteria. These data suggest that in depth investigations of the molecular processes of microorganisms adhering to surfaces are of great importance for the design of innovative biomaterials with active biological functionalities.

  20. Simple inorganic complexes but intricate hydrogen bonding ...

    Indian Academy of Sciences (India)

    Administrator

    We are interested in obtaining single crystals of metal-opda complexes because their crystal structures would show complex hydrogen bonding network due to the presence of. –NH2 groups in the opda ligand (hydrogen bonding donor sites) and inorganic anions having mostly oxo groups (hydrogen bonding acceptor sites) ...

  1. Medicinal Uses of Inorganic Compounds - 1

    Indian Academy of Sciences (India)

    Worldwide sales of inorganic drugs are growing rapidly. Although about 26 elements in the periodic table are considered essential for mammalian life, both ... Lithium like alcohol can influence mood. Lithium drugs such as lithium carbonate Li2C03. , are used for the treatment of manic-depressive disorders, most likely ...

  2. Corrosion performance of inorganic coatings in seawater

    NARCIS (Netherlands)

    Zhang, X.; Buter, S.J.; Ferrari, G.M.; Westing, E. van; Kowalski, L.

    2011-01-01

    Inorganic coatings are widely used to protect carbon steel hydraulic cylinder rods from wear and corrosion in aggressive offshore environment. Different types of lay-ers such as Ni/Cr, Al2O3, Cr2O3, TiO2, and Inconel 625 layers were applied to the carbon steels by plasma, High Velocity Oxygen Fuel

  3. Inorganic mass spectrometry of solid samples

    International Nuclear Information System (INIS)

    Adams, F.; Vertes, A.

    1990-01-01

    In this review some recent developments in the field of inorganic mass spectrometry of solids are described with special emphasis on the actual state of understanding of the ionization processes. It concentrates on the common characteristics of methods such as spark source-, laser-, secondary ion-, inductively coupled plasma- and glow discharge mass spectrometry. (orig.)

  4. INORGANIC ELEMENTS AND DISTRIBUTION OF EASTERN OYSTERS.

    Science.gov (United States)

    Fisher, William S. In press. Inorganic Elements and Distribution of Eastern Oysters (Abstract). To be presented at the 96th Annual Meeting (Aquaculture 2004) of the National Shellfisheries Association, 1-5 March 2004, Honolulu, HI. 1 p. (ERL,GB R962). For over a century w...

  5. Serum Calcium, Inorganic Phosphates and some Haematological ...

    African Journals Online (AJOL)

    Objectives: Sickle cell disease has long been associated with bone deformities and pain. Mineral salts such as calcium and inorganic phosphate are critical in bone formation and metabolism. This investigation was designed to study the serum concentration of these minerals as well as some haematological parameters in ...

  6. Studies on inorganic exchanger: zirconium antimonate

    International Nuclear Information System (INIS)

    Dash, A.; Balasubramanian, K.R.

    1992-01-01

    The inorganic exchanger zirconium antimonate has been prepared and its characteristics evaluated. A method has been developed for the separation of 90 Sr and 144 Ce from fission products solution using this exchanger. (author). 23 refs., 18 f igs., 9 tabs

  7. Phytochemical, inorganic and proximate composition-guided ...

    African Journals Online (AJOL)

    Sterols, glycosides and anthraquinone were absent in all samples. The inorganic composition result showed relatively high concentration of potassium (very high for seed), calcium (for bark and leaf), magnesium and sulphur in Avocado samples. The Avocado seed contained relatively high content of moisture, carbohydrate ...

  8. Microbiological disproportionation of inorganic sulfur compounds

    DEFF Research Database (Denmark)

    Finster, Kai

    2008-01-01

    The disproportionation of inorganic sulfur intermediates at moderate temperatures (0-80 °C) is a microbiologically catalyzed chemolithotrophic process in which compounds like elemental sulfur, thiosulfate, and sulfite serve as both electron donor and acceptor, and generate hydrogen sulfide and su...

  9. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  10. Thermoelectric efficiency of nanoscale devices in the linear regime

    Science.gov (United States)

    Bevilacqua, G.; Grosso, G.; Menichetti, G.; Pastori Parravicini, G.

    2016-12-01

    We study quantum transport through two-terminal nanoscale devices in contact with two particle reservoirs at different temperatures and chemical potentials. We discuss the general expressions controlling the electric charge current, heat currents, and the efficiency of energy transmutation in steady conditions in the linear regime. With focus in the parameter domain where the electron system acts as a power generator, we elaborate workable expressions for optimal efficiency and thermoelectric parameters of nanoscale devices. The general concepts are set at work in the paradigmatic cases of Lorentzian resonances and antiresonances, and the encompassing Fano transmission function: the treatments are fully analytic, in terms of the trigamma functions and Bernoulli numbers. From the general curves here reported describing transport through the above model transmission functions, useful guidelines for optimal efficiency and thermopower can be inferred for engineering nanoscale devices in energy regions where they show similar transmission functions.

  11. Nanoscale shape-memory alloys for ultrahigh mechanical damping.

    Science.gov (United States)

    San Juan, Jose; Nó, Maria L; Schuh, Christopher A

    2009-07-01

    Shape memory alloys undergo reversible transformations between two distinct phases in response to changes in temperature or applied stress. The creation and motion of the internal interfaces between these phases during such transformations dissipates energy, making these alloys effective mechanical damping materials. Although it has been shown that reversible phase transformations can occur in nanoscale volumes, it is not known whether these transformations have a sample size dependence. Here, we demonstrate that the two phases responsible for shape memory in Cu-Al-Ni alloys are more stable in nanoscale pillars than they are in the bulk. As a result, the pillars show a damping figure of merit that is substantially higher than any previously reported value for a bulk material, making them attractive for damping applications in nanoscale and microscale devices.

  12. Study of nanoscale structural biology using advanced particle beam microscopy

    Science.gov (United States)

    Boseman, Adam J.

    This work investigates developmental and structural biology at the nanoscale using current advancements in particle beam microscopy. Typically the examination of micro- and nanoscale features is performed using scanning electron microscopy (SEM), but in order to decrease surface charging, and increase resolution, an obscuring conductive layer is applied to the sample surface. As magnification increases, this layer begins to limit the ability to identify nanoscale surface structures. A new technology, Helium Ion Microscopy (HIM), is used to examine uncoated surface structures on the cuticle of wild type and mutant fruit flies. Corneal nanostructures observed with HIM are further investigated by FIB/SEM to provide detailed three dimensional information about internal events occurring during early structural development. These techniques are also used to reconstruct a mosquito germarium in order to characterize unknown events in early oogenesis. Findings from these studies, and many more like them, will soon unravel many of the mysteries surrounding the world of developmental biology.

  13. Influence of Organic and Inorganic Sources of Fertilizer on Growth ...

    African Journals Online (AJOL)

    Influence of Organic and Inorganic Sources of Fertilizer on Growth and Leaf Yield of Kale ... Journal of Agriculture, Science and Technology ... fertilizer gave leaf yields comparable to those applied with exclusively inorganic sources of fertilizer.

  14. Light-matter interaction physics and engineering at the nanoscale

    CERN Document Server

    Weiner, John

    2013-01-01

    This book draws together the essential elements of classical electrodynamics, surface wave physics, plasmonic materials, and circuit theory of electrical engineering to provide insight into the essential physics of nanoscale light-matter interaction and to provide design methodology for practical nanoscale plasmonic devices. A chapter on classical and quantal radiation also highlights the similarities (and differences) between the classical fields of Maxwell's equations and the wave functions of Schrodinger's equation. The aim of this chapter is to provide a semiclassical picture of atomic absorption and emission of radiation, lending credence and physical plausibility to the "rules" of standard wave-mechanical calculations.

  15. Topology optimization for nano-scale heat transfer

    DEFF Research Database (Denmark)

    Evgrafov, Anton; Maute, Kurt; Yang, Ronggui

    2009-01-01

    We consider the problem of optimal design of nano-scale heat conducting systems using topology optimization techniques. At such small scales the empirical Fourier's law of heat conduction no longer captures the underlying physical phenomena because the mean-free path of the heat carriers, phonons...... in our case, becomes comparable with, or even larger than, the feature sizes of considered material distributions. A more accurate model at nano-scales is given by kinetic theory, which provides a compromise between the inaccurate Fourier's law and precise, but too computationally expensive, atomistic...

  16. Quantitative nanoscale surface voltage measurement on organic semiconductor blends

    International Nuclear Information System (INIS)

    Cuenat, Alexandre; Muñiz-Piniella, Andrés; Muñoz-Rojo, Miguel; Murphy, Craig E; Tsoi, Wing C

    2012-01-01

    We report on the validation of a method based on Kelvin probe force microscopy (KPFM) able to measure the different phases and the relative work function of polymer blend heterojunctions at the nanoscale. The method does not necessitate complex ultra-high vacuum setup. The quantitative information that can be extracted from the topography and the Kelvin probe measurements is critically analysed. Surface voltage difference can be observed at the nanoscale on poly(3-hexyl-thiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blends and dependence on the annealing condition and the regio-regularity of P3HT is observed. (paper)

  17. Multiple simultaneous fabrication of molecular nanowires using nanoscale electrocrystallization

    International Nuclear Information System (INIS)

    Hasegawa, Hiroyuki; Ueda, Rieko; Kubota, Tohru; Mashiko, Shinro

    2006-01-01

    We carried out a multiple simultaneous fabrication based on the nanoscale electrocrystallization to simultaneously construct molecular nanowires at two or more positions. This substrate-independent nanoscale electrocrystallization process enables nanowires fabrication at specific positions using AC. We also succeeded in multiple fabrications only at each gap between the electrode tips. We found that π-stack was formed along the long axis of the nanowires obtained by analyzing the selected-area electron diffraction. We believe this technique has the potential for expansion to the novel low-cost and energy-saving fabrication of high-performance nanodevices

  18. Toxicity of inhaled 238PuO2 in beagle dogs. A. Monodisperse 1.5 μm 238PuO2. B. Monodisperse 3.0 μm 238PuO2 particles. III

    International Nuclear Information System (INIS)

    Lustgarten, C.S.; Mewhinney, J.A.; Hobbs, C.H.; Halliwell, W.H.; Jones, R.K.; Mauderly, J.L.; McClellan, R.O.; Mo, T.; Pickrell, J.A.

    1976-01-01

    To obtain essential information on the importance of the homogeneity or non-homogeneity of the radiation dose to lung (the hot particle question), Beagle dogs have been exposed to monodisperse aerosols (sigma/sub g/ 238 PuO 2 of either 1.5 μm or 3.0 μm aerodynamic diameter (AD). By using monodisperse particles of these two sizes, the average dose to lung is held constant for a given initial lung burden, but the local alpha dose around the two sizes of particles varies by a factor of about ten. All exposures have been completed with 72 days exposed to each of the two particle sizes of 238 PuO 2 (total of 144 dogs) resulting in graded initial lung burdens which range from .005 to 2.2 μCi/kg of body weight. Twenty-four dogs exposed to the diluent aerosol are serving as controls. The animals will be studied over their total life span. Two exposed dogs have died from pulmonary injury: Dog 710C (with an initial lung burden of 2.0 μCi/kg) died at 631 days after inhalation of 3.0 μm AD aerosol. The cause of death was radiation pneumonitis and pulmonary fibrosis, Dog 746B (with an initial lung burden of 1.3 μCi/kg) died at 791 days after inhalation of 1.5 μm AD aerosol. Death was attributed to intrapulmonic hemorrhage resulting from a degenerative vasculitis. One control dog (721A) was euthanized at 820 days after exposure due to a meningitis and encephalomalacia that caused a severe central nervous system disorder that made the dog difficult to handle.A leukopenia in exposed dogs to date has occurred earlier and to a greater degree in dogs exposed to 3.0 μm AD particles than in dogs that recevied 1.5 μm AD particles. One hundred forty-two exposed and 23 control dogs are surviving at 175 to 1024 days after exposure

  19. 78 FR 24241 - Nanoscale Science, Engineering, and Technology Subcommittee; Committee on Technology, National...

    Science.gov (United States)

    2013-04-24

    ... OFFICE OF SCIENCE AND TECHNOLOGY POLICY Nanoscale Science, Engineering, and Technology.... SUMMARY: The National Nanotechnology Coordination Office (NNCO), on behalf of the Nanoscale Science, Engineering, and Technology (NSET) Subcommittee of the Committee on Technology, National Science and...

  20. 77 FR 13159 - Nanoscale Science, Engineering, and Technology Subcommittee of the Committee on Technology...

    Science.gov (United States)

    2012-03-05

    ... OFFICE OF SCIENCE AND TECHNOLOGY POLICY Nanoscale Science, Engineering, and Technology... public meeting. SUMMARY: The National Nanotechnology Coordination Office (NNCO), on behalf of the Nanoscale Science, Engineering, and Technology (NSET) Subcommittee of the Committee on Technology, National...

  1. 77 FR 56681 - Nanoscale Science, Engineering, and Technology Subcommittee; Committee on Technology, National...

    Science.gov (United States)

    2012-09-13

    ... OFFICE OF SCIENCE AND TECHNOLOGY POLICY Nanoscale Science, Engineering, and Technology...: Notice of webinar. SUMMARY: The National Nanotechnology Coordination Office (NNCO), on behalf of the Nanoscale Science, Engineering, and Technology (NSET) Subcommittee of the Committee on Technology, National...

  2. 77 FR 61448 - Nanoscale Science, Engineering and Technology Subcommittee Committee on Technology, National...

    Science.gov (United States)

    2012-10-09

    ... OFFICE OF SCIENCE AND TECHNOLOGY POLICY Nanoscale Science, Engineering and Technology Subcommittee...: The National Nanotechnology Coordination Office (NNCO), on behalf of the Nanoscale Science, Engineering, and Technology (NSET) Subcommittee of the Committee on Technology, National Science and...

  3. Review of progress in soil inorganic carbon research

    Science.gov (United States)

    Bai, S. G.; Jiao, Y.; Yang, W. Z.; Gu, P.; Yang, J.; Liu, L. J.

    2017-12-01

    Soil inorganic carbon is one of the main carbon banks in the near-surface environment, and is the main form of soil carbon library in arid and semi-arid regions, which plays an important role in the global carbon cycle. This paper mainly focuses on the inorganic dynamic process of soil inorganic carbon in soil environment in arid and semi-arid regions, and summarized the composition and source of soil inorganic carbon, influence factors and soil carbon sequestration.

  4. Quantitative method for determination of body inorganic iodine

    International Nuclear Information System (INIS)

    Filatov, A.A.; Tatsievskij, V.A.

    1991-01-01

    An original method of quantitation of body inorganic iodine, based upon a simultaneous administration of a known dose of stable and radioactive iodine with subsequent radiometry of the thyroid was proposed. The calculation is based upon the principle of the dilution of radiactive iodine in human inorganic iodine space. The method permits quantitation of the amount of inorganic iodine with regard to individual features of inorganic space. The method is characterized by simplicity and is not invasive for a patient

  5. Inorganic component of saliva during fasting and after fast break

    OpenAIRE

    Samad, Rasmidar

    2016-01-01

    Oral health is closely related to salivary components. Saliva consists of water, inorganic and organic materials. Fasting changes one???s meal and drinking time that in turn can affect the environment in oral cavity, including inorganic componenet of saliva. The purpose of this study is to determine the inorganic component of saliva during fasting and after fast break.

  6. First report on soapnut extract-mediated synthesis of sulphur-substituted nanoscale NdFeB permanent magnets and their characterization

    Science.gov (United States)

    Jayapala Rao, G. V. S.; Prasad, T. N. V. K. V.; Shameer, Syed; Arun, T.; Purnachandra Rao, M.

    2017-10-01

    Biosynthesis of nanoscale materials has its own advantages over other physical and chemical methods. Using soapnut extract as reducing and stabilizing agent for the synthesis of inorganic nanoscale materials is novel and has not been exploited to its potential so far. Herein, we report for the first time on the effects of sulphur substitution on soapnut extract-mediated synthesis of nanoscale NdFeB (S-NdFeB) permanent magnetic powders (Nd 15%, Fe 77.5%, B 7.5% and S with molar ratios: 0.1, 0.2, 0.3, 0.4, and 0.5). To synthesize, a 10 ml of 10% soapnut extract was added to 90 ml of respective chemical composition and heated to 60 °C for 30 min and aged for 24 h. The dried powder was sintered at 500 °C for 1 h. The characterization of the as-prepared nanoscale S-NdFeB magnetic materials was done using the techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS for size and zeta potential measurements) and vibrating sample magnetometer (VSM)-hysteresis loop studies. The results revealed that particles were highly stable (with a negative zeta potential of 25.7 mV) with irregular and spherical shape (with measured hydrodynamic diameter 6.7 and 63.5 nm). The tetragonal structures of the formed powders were revealed by XRD micrographs. Hysteresis loop studies clearly indicate the effect of S concentration on the enhanced magnetization of the materials.

  7. Final Report for Fractionation and Separation of Polydisperse Nanoparticles into Distinct Monodisperse Fractions Using CO2 Expanded Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Chistopher Roberts

    2007-08-31

    The overall objective of this project was to facilitate efficient fractionation and separation of polydisperse metal nanoparticle populations into distinct monodisperse fractions using the tunable solvent properties of gas expanded liquids. Specifically, the dispersibility of ligand-stabilized nanoparticles in an organic solution was controlled by altering the ligand-solvent interaction (solvation) by the addition of carbon dioxide (CO{sub 2}) gas as an antisolvent (thereby tailoring the bulk solvent strength) in a custom high pressure apparatus developed in our lab. This was accomplished by adjusting the CO{sub 2} pressure over the liquid dispersion, resulting in a simple means of tuning the nanoparticle precipitation by size. Overall, this work utilized the highly tunable solvent properties of organic/CO{sub 2} solvent mixtures to selectively size-separate dispersions of polydisperse nanoparticles (ranging from 1 to 20 nm in size) into monodisperse fractions ({+-}1nm). Specifically, three primary tasks were performed to meet the overall objective. Task 1 involved the investigation of the effects of various operating parameters (such as temperature, pressure, ligand length and ligand type) on the efficiency of separation and fractionation of Ag nanoparticles. In addition, a thermodynamic interaction energy model was developed to predict the dispersibility of different sized nanoparticles in the gas expanded liquids at various conditions. Task 2 involved the extension of the experimental procedures identified in task 1 to the separation of other metal particles used in catalysis such as Au as well as other materials such as semiconductor particles (e.g. CdSe). Task 3 involved using the optimal conditions identified in tasks 1 and 2 to scale up the process to handle sample sizes of greater than 1 g. An experimental system was designed to allow nanoparticles of increasingly smaller sizes to be precipitated sequentially in a vertical series of high pressure vessels by

  8. Cationic nanoparticles induce nanoscale disruption in living cell plasma membranes.

    Science.gov (United States)

    Chen, Jiumei; Hessler, Jessica A; Putchakayala, Krishna; Panama, Brian K; Khan, Damian P; Hong, Seungpyo; Mullen, Douglas G; Dimaggio, Stassi C; Som, Abhigyan; Tew, Gregory N; Lopatin, Anatoli N; Baker, James R; Holl, Mark M Banaszak; Orr, Bradford G

    2009-08-13

    It has long been recognized that cationic nanoparticles induce cell membrane permeability. Recently, it has been found that cationic nanoparticles induce the formation and/or growth of nanoscale holes in supported lipid bilayers. In this paper, we show that noncytotoxic concentrations of cationic nanoparticles induce 30-2000 pA currents in 293A (human embryonic kidney) and KB (human epidermoid carcinoma) cells, consistent with a nanoscale defect such as a single hole or group of holes in the cell membrane ranging from 1 to 350 nm(2) in total area. Other forms of nanoscale defects, including the nanoparticle porating agents adsorbing onto or intercalating into the lipid bilayer, are also consistent; although the size of the defect must increase to account for any reduction in ion conduction, as compared to a water channel. An individual defect forming event takes 1-100 ms, while membrane resealing may occur over tens of seconds. Patch-clamp data provide direct evidence for the formation of nanoscale defects in living cell membranes. The cationic polymer data are compared and contrasted with patch-clamp data obtained for an amphiphilic phenylene ethynylene antimicrobial oligomer (AMO-3), a small molecule that is proposed to make well-defined 3.4 nm holes in lipid bilayers. Here, we observe data that are consistent with AMO-3 making approximately 3 nm holes in living cell membranes.

  9. Direct Probing of Polarization Charge at Nanoscale Level

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Owoong [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Seol, Daehee [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Lee, Dongkyu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Han, Hee [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Lindfors-Vrejoiu, Ionela [Univ. of Cologne (Germany). Physics Inst.; Lee, Woo [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Jesse, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Lee, Ho Nyung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Kalinin, Sergei V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Alexe, Marin [Univ. of Warwick, Coventry (United Kingdom). Dept. of Physics; Kim, Yunseok [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering

    2017-11-14

    Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long-term development of reducing the sizes of devices, the preparation of ferroelectric materials and devices is entering the nanometer-scale regime. In order to evaluate the ferroelectricity, there is a need to investigate the polarization charge at the nanoscale. Nonetheless, it is generally accepted that the detection of polarization charges using a conventional conductive atomic force microscopy (CAFM) without a top electrode is not feasible because the nanometer-scale radius of an atomic force microscopy (AFM) tip yields a very low signal-to-noise ratio. But, the detection is unrelated to the radius of an AFM tip and, in fact, a matter of the switched area. In this work, the direct probing of the polarization charge at the nanoscale is demonstrated using the positive-up-negative-down method based on the conventional CAFM approach without additional corrections or circuits to reduce the parasitic capacitance. The polarization charge densities of 73.7 and 119.0 µC cm-2 are successfully probed in ferroelectric nanocapacitors and thin films, respectively. The results we obtained show the feasibility of the evaluation of polarization charge at the nanoscale and provide a new guideline for evaluating the ferroelectricity at the nanoscale.

  10. Charge transport in nanoscale vertical organic semiconductor pillar devices

    NARCIS (Netherlands)

    Wilbers, J.G.E.; Xu, B.; Bobbert, P.A.; de Jong, M.P.; van der Wiel, W.G.

    2017-01-01

    We report charge transport measurements in nanoscale vertical pillar structures incorporating ultrathin layers of the organic semiconductor poly(3-hexylthiophene) (P3HT). P3HT layers with thickness down to 5 nm are gently top-contacted using wedging transfer, yielding highly reproducible, robust

  11. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.; Ghoneim, Mohamed T.; Fahad, Hossain M.; Rojas, Jhonathan Prieto; Hussain, Aftab M.; Hussain, Muhammad Mustafa

    2014-01-01

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show

  12. Nanomaterial Case Studies: Nanoscale Titanium Dioxide (External Review Draft)

    Science.gov (United States)

    This draft document presents two case studies of nanoscale titanium dioxide (nano-TiO2) used (1) to remove arsenic from drinking water and (2) as an active ingredient in topical sunscreen. The draft case studies are organized around a comprehensive environmental asses...

  13. Generation and manipulation of monodispersed ferrofluid emulsions: the effect of a uniform magnetic field in flow-focusing and T-junction configurations.

    Science.gov (United States)

    Tan, Say Hwa; Nguyen, Nam-Trung

    2011-09-01

    This paper demonstrates the use of magnetically controlled microfluidic devices to produce monodispersed ferrofluid emulsions. By applying a uniform magnetic field on flow-focusing and T-junction configurations, the size of the ferrofluid emulsions can be actively controlled. The influences of the flow rates, the orientation, and the polarity of the magnetic field on the size of ferrofluid emulsions produced in both flow-focusing and T-junction configurations are compared and discussed.

  14. Characterizing the inorganic/organic interface in cancer bone metastasis

    Science.gov (United States)

    Wu, Fei

    Bone metastasis frequently occurs in patients with advanced breast cancer and remains a major source of mortality. At the molecular level, bone is a nanocomposite composed of inorganic bone mineral deposited within an organic extracellular matrix (ECM). Although the exact mechanisms of bone metastasis remain unclear, the nanoscale materials properties of bone mineral have been implicated in this process. Bone apatite is closely related to synthetic hydroxyapatite (HAP, Ca10(PO4)6(OH)2) in terms of structural and mechanical properties. Additionally, although the primary protein content of bone is collagen I, the glycoprotein fibronectin (Fn) is essential in maintaining the overall integrity of the bone matrix. Importantly, in vivo, neither breast cancer cells nor normal bone cells interact directly with the bone mineral but rather with the protein film adsorbed onto the mineral surface. Therefore, we hypothesized that breast cancer cell functions were regulated by differential fibronectin adsorption onto hydroxyapatite, which led to pathological remodeling of the bone matrix and sustained bone metastasis. Three model systems containing HAP and Fn were developed for this thesis. In model system I, a library of synthetic HAP nanoparticles were utilized to investigate the effect of mineral size, shape, and crystallinity on Fn conformation, using Forster resonance energy transfer (FRET) spectroscopy. In model system II, Fn-functionalized large geologic HAP crystals were used instead of HAP nanoparticles to avoid cellular uptake when investigating subsequent cell functions. Overall our FRET analysis (models I and II) revealed that Fn conformation depended on size, surface chemistry, and roughness of underlying HAP. When breast cancer cells were seeded on the Fn-coated HAP crystal facets (model II), our data indicated high secretion levels of proangiogenic and proinflammatory factors associated with the presence of unfolded Fn conformations, likely caused by differential

  15. Radwaste issues belong in the inorganic classroom

    International Nuclear Information System (INIS)

    Williams, D.H.

    1991-01-01

    The safe isolation of high level radioactive wastes is a matter of significant importance. This material is derived primarily from spent nuclear fuel and defense weapon production. Every element on the periodic chart is represented. The majority are metallic elements. Over the thousands of years that they are to be isolated the primary chemistry will be oxidation. The mobility and fate of particular inner and outer transition element ions become very important. For that, one must understand their hydrolytic nature, their complexing tendencies and the solubilities of various compounds. This topic could easily serve as a centerpiece for an inorganic chemistry course. At the very least, it demands the attention of every teacher of inorganic chemistry and consideration by those whose research is directed to tangible problems. The discussion includes notes on the abundance and lifetimes of particular radioisotopes. The positive student responses to this approach are also shared

  16. The quest for the ideal inorganic scintillator

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Weber, M.J.; Bourret-Courchesne, E.; Klintenberg, M.K.

    2002-01-01

    The past half century has witnessed the discovery of many new inorganic scintillator materials and numerous advances in our understanding of the basic physical processes governing the transformation of ionizing radiation into scintillation light. Whereas scintillators are available with a good combination of physical properties, none provides the desired combination of stopping power, light output, and decay time. A review of the numerous scintillation mechanisms of known inorganic scintillators reveals why none of them is both bright and fast. The mechanisms of radiative recombination in wide-bandgap direct semiconductors, however, remain relatively unexploited for scintillators. We describe how suitably doped semiconductor scintillators could provide a combination of high light output, short decay time, and linearity of response that approach fundamental limits

  17. Molten salt battery having inorganic paper separator

    Science.gov (United States)

    Walker, Jr., Robert D.

    1977-01-01

    A high temperature secondary battery comprises an anode containing lithium, a cathode containing a chalcogen or chalcogenide, a molten salt electrolyte containing lithium ions, and a separator comprising a porous sheet comprising a homogenous mixture of 2-20 wt.% chrysotile asbestos fibers and the remainder inorganic material non-reactive with the battery components. The non-reactive material is present as fibers, powder, or a fiber-powder mixture.

  18. Inorganic Materials Division annual report, 1975

    International Nuclear Information System (INIS)

    Duba, A.; Hornady, B.

    1976-01-01

    This compilation lists abstracts of papers, internal reports, and talks presented during 1975 at national and international meetings by members of the Geoscience and Engineering Section, Inorganic Materials Division, Chemistry and Materials Science Department, Lawrence Livermore Laboratory. Titles of talks at university and local meetings are also listed when available. The subjects range from the in situ retorting of coal to the temperature profile of the moon. A subject classification is included

  19. Organic-Inorganic Hybrid Hollow Mesoporous Organosilica Nanoparticles for Efficient Ultrasound-Based Imaging and Controlled Drug Release

    Directory of Open Access Journals (Sweden)

    Xiaoqin Qian

    2014-01-01

    Full Text Available A novel anticancer drug delivery system with contrast-enhanced ultrasound-imaging performance was synthesized by a typical hard-templating method using monodispersed silica nanoparticles as the templates, which was based on unique molecularly organic/inorganic hybrid hollow periodic mesoporous organosilicas (HPMOs. The highly dispersed HPMOs show the uniform spherical morphology, large hollow interior, and well-defined mesoporous structures, which are very beneficial for ultrasound-based theranostics. The obtained HPMOs exhibit excellent performances in contrast-enhanced ultrasonography both in vitro and in vivo and can be used for the real-time determination of the progress of lesion tissues during the chemotherapeutic process. Importantly, hydrophobic paclitaxel- (PTX- loaded HPMOs combined with ultrasound irradiation show fast ultrasound responsiveness for controlled drug release and higher in vitro and in vivo tumor inhibition rates compared with free PTX and PTX-loaded HPMOs, which is due to the enhanced ultrasound-triggered drug release and ultrasound-induced cavitation effect. Therefore, the achieved novel HPMOs-based nanoparticle systems will find broad application potentials in clinically ultrasound-based imaging and auxiliary tumor chemotherapy.

  20. Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

    Science.gov (United States)

    Shi, Weidong; Song, Shuyan; Zhang, Hongjie

    2013-07-07

    Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

  1. Inorganic particle analysis of dental impression elastomers.

    Science.gov (United States)

    Carlo, Hugo Lemes; Fonseca, Rodrigo Borges; Soares, Carlos José; Correr, Américo Bortolazzo; Correr-Sobrinho, Lourenço; Sinhoreti, Mário Alexandre Coelho

    2010-01-01

    The aim of this study was to determine quantitatively and qualitatively the inorganic particle fraction of commercially available dental elastomers. The inorganic volumetric fraction of two addition silicones (Reprosil Putty/Fluid and Flexitime Easy Putty/Fluid), three condensation silicones (Clonage Putty/Fluid, Optosil Confort/Xantopren VL and Silon APS Putty/Fluid), one polyether (Impregum Soft Light Body) and one polysulfide (Permlastic Light Body) was accessed by weighing a previously determined mass of each material in water before and after burning samples at 600 ºC, during 3 h. Unsettled material samples were soaked in acetone and chloroform for removal of the organic portion. The remaining filler particles were sputter-coated with gold evaluation of their morphology and size, under scanning electron microscopy (SEM). Flexitime Easy Putty was the material with the highest results for volumetric particle fraction, while Impregum Soft had the lowest values. Silon 2 APS Fluid presented the lowest mean filler size values, while Clonage Putty had the highest values. SEM micrographs of the inorganic particles showed several morphologies - lathe-cut, spherical, spherical-like, sticks, and sticks mixed to lathe-cut powder. The results of this study revealed differences in particle characteristics among the elastometic materials that could lead to different results when testing mechanical properties.

  2. Human proton coupled folic acid transporter is a monodisperse oligomer in the lauryl maltose neopentyl glycol solubilized state.

    Science.gov (United States)

    Aduri, Nanda G; Ernst, Heidi A; Prabhala, Bala K; Bhatt, Shweta; Boesen, Thomas; Gajhede, Michael; Mirza, Osman

    2018-01-08

    The human proton coupled folic acid transporter PCFT is the major import route for dietary folates. Mutations in the gene encoding PCFT cause hereditary folic acid malabsorption, which manifests itself by compromised folate absorption from the intestine and also in impaired folate transport into the central nervous system. Since its recent discovery, PCFT has been the subject of numerous biochemical studies aiming at understanding its structure and mechanism. One major focus has been its oligomeric state, with some reports supporting oligomers and others a monomer. Here, we report the overexpression and purification of recombinant PCFT. Following detergent screening, n-Dodecyl β-D-maltoside (DDM) and lauryl maltose neopentyl glycol (LMNG) were chosen for further work as they exhibited the most optimal solubilization. We found that purified detergent solubilized PCFT was able to bind folic acid, thus indicating a functionally active protein. Size exclusion chromatography showed that PCFT in DDM was polydisperse; the LMNG preparation was clearly monodisperse but with shorter retention time than the major DDM peak. To assess the oligomeric state negative stain electron microscopy was performed which showed a particle with the size of a PCFT dimer. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

    Science.gov (United States)

    Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

    2017-01-01

    Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

  4. Insights into magnetic interactions in a monodisperse Gd{sub 12}Fe{sub 14} metal cluster

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xiu-Ying; Zhang, Hui; Liu, Pengxin; Du, Ming-Hao; Han, Ying-Zi; Wei, Rong-Jia; Kong, Xiang-Jian; Long, La-Sheng; Zheng, Lan-Sun [Collaborative Innovation Center of Chemistry for Energy Materials, State Key Lab. of Physical Chemistry of Solid Surface and Dept. of Chemistry, College of Chemistry and Chemical Engineering, Xiamen Univ. (China); Wang, Zhenxing; Ouyang, Zhong-Wen [Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan (China); Zhuang, Gui-Lin [College of Chemcal Engineering, Zhejiang University of Technology, Hangzhou (China)

    2017-09-11

    The largest Ln-Fe metal cluster [Gd{sub 12}Fe{sub 14}(μ{sub 3}-OH){sub 12}(μ{sub 4}-OH){sub 6}(μ{sub 4}-O){sub 12}(TEOA){sub 6}(CH{sub 3}COO){sub 16}(H{sub 2} O){sub 8}].(CH{sub 3}COO){sub 2}(CH{sub 3}CN){sub 2}.(H{sub 2}O){sub 20} (1) and the core-shell monodisperse metal cluster of 1 a rate at SiO{sub 2} (1 a=[Gd{sub 12}Fe{sub 14}(μ{sub 3}-OH){sub 12}(μ{sub 4}-OH){sub 6}(μ{sub 4}-O){sub 12}(TEOA){sub 6}(CH{sub 3}COO){sub 16} (H{sub 2}O){sub 8}]{sup 2+}) were prepared. Experimental and theoretical studies on the magnetic properties of 1 and 1 a rate at SiO{sub 2} reveal that encapsulation of one cluster into one silica nanosphere not only effectively decreases intermolecular magnetic interactions but also significantly increases the zero-field splitting effect of the outer layer Fe{sup 3+} ions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Facile synthesis of monodisperse superparamagnetic Fe{sub 3}O{sub 4}/PMMA composite nanospheres with high magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Lan Fang; Liu Kexia; Jiang Wen; Zeng Xiaobo; Wu Yao; Gu Zhongwei, E-mail: Yaowu_amanda@126.com, E-mail: zwgu@scu.edu.cn [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

    2011-06-03

    Monodisperse superparamagnetic Fe{sub 3}O{sub 4}/polymethyl methacrylate (PMMA) composite nanospheres with high saturation magnetization were successfully prepared by a facile novel miniemulsion polymerization method. The ferrofluid, MMA monomer and surfactants were co-sonicated and emulsified to form stable miniemulsion for polymerization. The samples were characterized by DLS, TEM, FTIR, XRD, TGA and VSM. The diameter of the Fe{sub 3}O{sub 4}/PMMA composite nanospheres by DLS was close to 90 nm with corresponding polydispersity index (PDI) as small as 0.099, which indicated that the nanospheres have excellent homogeneity in aqueous medium. The TEM results implied that the Fe{sub 3}O{sub 4}/PMMA composite nanospheres had a perfect core-shell structure with about 3 nm thin PMMA shells, and the core was composed of many homogeneous and closely packed Fe{sub 3}O{sub 4} nanoparticles. VSM and TGA showed that the Fe{sub 3}O{sub 4}/PMMA composite nanospheres with at least 65% high magnetite content were superparamagnetic, and the saturation magnetization was as high as around 39 emu g{sup -1} (total mass), which was only decreased by 17% compared with the initial bare Fe{sub 3}O{sub 4} nanoparticles.

  6. Cluster synthesis of monodisperse rutile-TiO2 nanoparticles and dielectric TiO2-vinylidene fluoride oligomer nanocomposites

    International Nuclear Information System (INIS)

    Balasubramanian, Balamurugan; Kraemer, Kristin L; Valloppilly, Shah R; Ducharme, Stephen; Sellmyer, David J

    2011-01-01

    The embedding of oxide nanoparticles in polymer matrices produces a greatly enhanced dielectric response by combining the high dielectric strength and low loss of suitable host polymers with the high electric polarizability of nanoparticles. The fabrication of oxide-polymer nanocomposites with well-controlled distributions of nanoparticles is, however, challenging due to the thermodynamic and kinetic barriers between the polymer matrix and nanoparticle fillers. In the present study, monodisperse TiO 2 nanoparticles having an average particle size of 14.4 nm and predominant rutile phase were produced using a cluster-deposition technique without high-temperature thermal annealing and subsequently coated with uniform vinylidene fluoride oligomer (VDFO) molecules using a thermal evaporation source, prior to deposition as TiO 2 -VDFO nanocomposite films on suitable substrates. The molecular coatings on TiO 2 nanoparticles serve two purposes, namely to prevent the TiO 2 nanoparticles from contacting each other and to couple the nanoparticle polarization to the matrix. Parallel-plate capacitors made of TiO 2 -VDFO nanocomposite film as the dielectric exhibit minimum dielectric dispersion and low dielectric loss. Dielectric measurements also show an enhanced effective dielectric constant in TiO 2 -VDFO nanocomposites as compared to that of pure VDFO. This study demonstrates for the first time a unique electroactive particle coating in the form of a ferroelectric VDFO that has high-temperature stability as compared to conventionally used polymers for fabricating dielectric oxide-polymer nanocomposites.

  7. A posteriori determination of the useful data range for small-angle scattering experiments on dilute monodisperse systems.

    Science.gov (United States)

    Konarev, Petr V; Svergun, Dmitri I

    2015-05-01

    Small-angle X-ray and neutron scattering (SAXS and SANS) experiments on solutions provide rapidly decaying scattering curves, often with a poor signal-to-noise ratio, especially at higher angles. On modern instruments, the noise is partially compensated for by oversampling, thanks to the fact that the angular increment in the data is small compared with that needed to describe adequately the local behaviour and features of the scattering curve. Given a (noisy) experimental data set, an important question arises as to which part of the data still contains useful information and should be taken into account for the interpretation and model building. Here, it is demonstrated that, for monodisperse systems, the useful experimental data range is defined by the number of meaningful Shannon channels that can be determined from the data set. An algorithm to determine this number and thus the data range is developed, and it is tested on a number of simulated data sets with various noise levels and with different degrees of oversampling, corresponding to typical SAXS/SANS experiments. The method is implemented in a computer program and examples of its application to analyse the experimental data recorded under various conditions are presented. The program can be employed to discard experimental data containing no useful information in automated pipelines, in modelling procedures, and for data deposition or publication. The software is freely accessible to academic users.

  8. Preparation and unique electrical behaviors of monodispersed hybrid nanorattles of metal nanocores with hairy electroactive polymer shells.

    Science.gov (United States)

    Cai, Tao; Zhang, Bin; Chen, Yu; Wang, Cheng; Zhu, Chun Xiang; Neoh, Koon-Gee; Kang, En-Tang

    2014-03-03

    A versatile template-assisted strategy for the preparation of monodispersed rattle-type hybrid nanospheres, encapsulating a movable Au nanocore in the hollow cavity of a hairy electroactive polymer shell (Au@air@PTEMA-g-P3HT hybrid nanorattles; PTEMA: poly(2-(thiophen-3-yl)ethyl methacrylate; P3HT: poly(3-hexylthiophene), was reported. The Au@silica core-shell nanoparticles, prepared by the modified Stöber sol-gel process on Au nanoparticle seeds, were used as templates for the synthesis of Au@silica@PTEMA core-double shell nanospheres. Subsequent oxidative graft polymerization of 3-hexylthiophene from the exterior surface of the Au@silica@PTEMA core-double shell nanospheres allowed the tailoring of surface functionality with electroactive P3HT brushes (Au@silica@PTEMA-g-P3HT nanospheres). The Au@air@ PTEMA-g-P3HT hybrid nanorattles were obtained after etching of the silica interlayer by HF. The as-prepared nanorattles were dispersed into an electrically insulating polystyrene matrix and for the first time used to fabricate nonvolatile memory devices. As a result, unique electrical behaviors, including insulator behavior, write-once-read-many-times and rewritable memory effects, and conductor behavior as well, were observed in the Al/Au@air@PTEMA-g-P3HT+PS/ITO (ITO: indium-tin oxide) sandwich thin-film devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Evaluation of {sup 211}At-labelled monodisperse polymer particles in vivo: comparison of different specific activities

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R.H.; Hoff, Per; Alstad, Jorolf [Oslo Univ., Chemistry Dept., Oslo (Norway); Varaas, Tone; De Vos, L.N.; Nustad, Kjell [Norwegian Radium Hospital, Central Lab., Oslo (Norway); Vergote, I.B. [Norwegian Radium Hospital, Gynecologic Oncology Dept., Oslo (Norway)

    1996-09-01

    The {alpha}-particle emitter {sup 211}At was covalently coupled to 1.8 {mu}m aminated monodisperse polymer particles (MDPP) and used to irradiate the intraperitoneal cavity in mice with disseminated tumour cells. Specific activity has previously been shown to influence the therapeutic efficacy of {alpha}-particle emitting compounds and the therapeutic efficacy of {sup 211}At-MDPP with various specific activity was therefore investigated. Groups of mice (10 animals per group) were treated with intraperitoneal injections of 100 kBq of {sup 211}At-MDPP with specific activities of 0.19, 0.55, 1.7, 5.0, 15, and 45 MBq/mg. A significantly prolonged survival was observed in the treated groups compared to the control group (from 19 to 26 days vs. 12 days, median). The difference in survival between the {sup 211}At-MDPP treated groups was not significant, but some animals with short survival were observed in the groups that had received the 0.19, 15 and 45 MBq/mg preparations. K13 monoclonal antibody values, which are an indicator of tumour growth, were high in some animals in the 15 and 45 MBq/mg groups (day 7 values). (author).

  10. Fabrication and characterisation of ligand-functionalised ultrapure monodispersed metal nanoparticle nanoassemblies employing advanced gas deposition technique

    Science.gov (United States)

    Geremariam Welearegay, Tesfalem; Cindemir, Umut; Österlund, Lars; Ionescu, Radu

    2018-02-01

    Here, we report for the first time the fabrication of ligand-functionalised ultrapure monodispersed metal nanoparticles (Au, Cu, and Pt) from their pure metal precursors using the advanced gas deposition technique. The experimental conditions during nanoparticle formation were adjusted in order to obtain ultrafine isolated nanoparticles on different substrates. The morphology and surface analysis of the as-deposited metal nanoparticles were investigated using scanning electron microscopy, x-ray diffraction and Fourier transform infra-red spectroscopy, which demonstrated the formation of highly ordered pure crystalline nanoparticles with a relatively uniform size distribution of ∼10 nm (Au), ∼4 nm (Cu) and ∼3 nm (Pt), respectively. A broad range of organic ligands containing thiol or amine functional groups were attached to the nanoparticles to form continuous networks of nanoparticle-ligand nanoassemblies, which were characterised by scanning electron microscopy and x-ray photoelectron spectroscopy. The electrical resistance of the functional nanoassemblies deposited in the gap spacing of two microfabricated parallel Au electrodes patterned on silicon substrates ranged between tens of kΩ and tens of MΩ, which is suitable for use in many applications including (bio)chemical sensors, surface-enhanced Raman spectroscopy and molecular electronic rectifiers.

  11. Enhanced visible light photocatalytic properties of Fe-doped TiO2 nanorod clusters and monodispersed nanoparticles

    International Nuclear Information System (INIS)

    Liu, Y.; Wei, J.H.; Xiong, R.; Pan, C.X.; Shi, J.

    2011-01-01

    In order to get photocatalysts with desired morphologies and enhanced visible light responses, the Fe-doped TiO 2 nanorod clusters and monodispersed nanoparticles were prepared by modified hydrothermal and solvothermal method, respectively. The microstructures and morphologies of TiO 2 crystals can be controlled by restraining the hydrolytic reaction rates. The Fe-doped photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy (UV-vis), N 2 adsorption-desorption measurement (BET), and photoluminescence spectroscopy (PL). The refinements of the microstructures and morphologies result in the enhancement of the specific surface areas. The Fe 3+ -dopants in TiO 2 lattices not only lead to the significantly extending of the optical responses from UV to visible region but also diminish the recombination rates of the electrons and holes. The photocatalytic activities were evaluated by photocatalytic decomposition of formaldehyde in air under visible light illumination. Compared with P25 (TiO 2 ) and N-doped TiO 2 nanoparticles, the Fe-doped photocatalysts show high photocatalytic activities under visible light.

  12. Macrocyclic receptors immobilized to monodisperse porous polymer particles by chemical grafting and physical impregnation for strontium capture: a comparative study.

    Science.gov (United States)

    Song, Yang; Du, Yi; Lv, Dachao; Ye, Gang; Wang, Jianchen

    2014-06-15

    Separation of strontium is of great significance for radioactive waste treatment and environmental remediation after nuclear accidents. In this work, a novel class of adsorbent (Crown-g-MPPPs) was synthesized by chemical grafting a macrocyclic ether receptor to monodisperse porous polymer particles (MPPPs) for strontium adsorption. Meanwhile, a counterpart material (Crown@MPPPs) with the receptor molecules immobilized to the MPPPs substrate by physical impregnation was prepared. To investigate how the immobilization manner and distribution of the receptors influence the adsorption ability, a comparative study on the adsorption behaviour of the two materials towards Sr(II) in HNO3 media was accomplished. Due to the shorter diffusion path and covalently-bonded structure, Crown-g-MPPPs showed faster adsorption kinetics and better stability for cycle use. While Crown@MPPPs had the advantages of facile synthesis and higher adsorption capacity, owing to the absence of conformational constraint to form complexation with Sr(II). Kinetic functions (Lagergren pseudo-first-order/pseudo-second-order functions) and adsorption isotherm models (Langmuir/Freundlich models) were used to fit the experimental data and examine the adsorption mechanism. On this basis, a chromatographic process was proposed by using Crown@MPPPs for an effective separation of Sr(II) (91%) in simulated high level liquid waste (HLLW). Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Monodisperse Pt atoms anchored on N-doped graphene as efficient catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin; Sui, Yanhui; Duan, Ting; Meng, Changgong; Han, Yu

    2015-01-01

    We performed first-principles based calculations to investigate the electronic structure and the potential catalytic performance of Pt atoms monodispersed on N-doped graphene in CO oxidation. We showed that N-doping can introduce localized defect states in the vicinity of the Fermi level of graphene which will effectively stabilize the deposited Pt atoms. The binding energy of a single Pt atom onto a stable cluster of 3 pyridinic N (PtN3) is up to -4.47 eV, making the diffusion and aggregation of anchored Pt atoms difficult. Both the reaction thermodynamics and kinetics suggest that CO oxidation over PtN3 would proceed through the Langmuir-Hinshelwood mechanism. The reaction barriers for the formation and dissociation of the peroxide-like intermediate are determined to be as low as 0.01 and 0.08 eV, respectively, while that for the regeneration is only 0.15 eV, proving the potential high catalytic performance of PtN3 in CO oxidation, especially at low temperatures. The Pt-d states that are up-shifted by the Pt-N interaction account for the enhanced activation of O2 and the efficient formation and dissociation of the peroxide-like intermediate.

  14. Droplet size effects on NO/x/ formation in a one-dimensional monodisperse spray combustion system

    Science.gov (United States)

    Sarv, H.; Nizami, A. A.; Cernansky, N. P.

    1982-01-01

    A one-dimensional monodisperse aerosol spray combustion facility is described and experimental results of post flame NO/NO(x) emissions are presented. Four different hydrocarbon fuels were studied: isopropanol, methanol, n-heptane, and n-octane. The results indicate an optimum droplet size in the range of 48-58 microns for minimizing NO/NO(x) production for all of the test fuels. This NO(x) behavior is associated with droplet interactions and the transition from diffusive type of spray burning to that of a prevaporized and premixed case. Decreasing the droplet size results in a trend of increasing droplet interactions, which suppresses temperatures and reduces NO(x). This trend continues until prevaporization effects begin to dominate and the system tends towards the premixed limit. The occurrence of the minimum NO(x) point at different droplet diameters for the different fuels appears to be governed by the extent of prevaporization of the fuel in the spray, and is consistent with theoretical calculations based on each fuel's physical properties.

  15. Preparation and characterization of monodisperse microcapsules with alginate and bentonite via external gelation technique encapsulating Pseudomonas putida Rs-198.

    Science.gov (United States)

    Li, Xuan; Wu, Zhansheng; He, Yanhui; Ye, Bang-Ce; Wang, Jun

    2017-10-01

    This paper evaluated the external gelation technique for preparing microcapsules. The microcapsules were consisted of Pseudomonas putida Rs-198 (Rs-198) core and sodium alginate (NaAlg)-bentonite (Bent) shell. Different emulsification rotation speeds and core/shell ratios were used to prepare the microcapsules of each formulation. The near-spherical microcapsules were monodisperse with a mean diameter of 25-100 μm and wrinkled surfaces. Fourier transform infrared spectrophotometry (FTIR) and thermogravimetric analysis (TGA) revealed the physical mixture of the wall material and the superior thermal stability of the microcapsules. Percentage yield, water content, and encapsulation efficiency were evaluated and correlated with the changes in emulsification rotation speed and core/shell ratio. In vitro release experiments demonstrated that 60% of the bacteria were released from the NaAlg-Bent microcapsules within three days. Considerably better survival was observed for encapsulated cells compared to free cells, especially in pH 4.0 and 10.0. In summary, the desired properties of microcapsules can be obtained by external gelation technique and the microcapsules on the bacteria had a good protective effect.

  16. Establishing the interfacial nano-structure and elemental composition of homeopathic medicines based on inorganic salts: a scientific approach.

    Science.gov (United States)

    Temgire, Mayur Kiran; Suresh, Akkihebbal Krishnamurthy; Kane, Shantaram Govind; Bellare, Jayesh Ramesh

    2016-05-01

    Extremely dilute systems arise in homeopathy, which uses dilution factors 10(60), 10(400) and also higher. These amounts to potencies of 30c, 200c or more, those are far beyond Avogadro's number. There is extreme skepticism among scientists about the possibility of presence of starting materials due to these high dilutions. This has led modern scientists to believe homeopathy may be at its best a placebo effect. However, our recent studies on 30c and 200c metal based homeopathic medicines clearly revealed the presence of nanoparticles of starting metals, which were found to be retained due to the manufacturing processes involved, as published earlier.(9,10) Here, we use HR-TEM and STEM techniques to study medicines arising from inorganic salts as starting materials. We show that the inorganic starting materials are present as nano-scale particles in the medicines even at 1 M potency (having a large dilution factor of 10(2000)). Thus this study has extended our physicochemical studies of metal based medicines to inorganic based medicines, and also to higher dilution. Further, we show that the particles develop a coat of silica: these particles were seen embedded in a meso-microporous silicate layer through interfacial encapsulation. Similar silicate coatings were also seen in metal based medicines. Thus, metal and inorganic salt based homeopathic medicines retain the starting material as nanoparticles encapsulated within a silicate coating. On the basis of these studies, we propose a universal microstructural hypothesis that all types of homeopathic medicines consist of silicate coated nano-structures dispersed in the solvent. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  17. Analytical TEM investigations of nanoscale magnetic materials

    International Nuclear Information System (INIS)

    Meingast, A.

    2015-01-01

    Analytical transmission electron microscopy has been applied within this thesis to investigate several novel approaches to design and fabricate nanoscale magnetic materials. As the size of the features of interest rank in the sub-nanometer range, it is necessary to employ techniques with a resolution – both spatial and analytical – well below this magnitude. Only at this performance level it is possible to examine material properties, necessary for the further tailoring of materials. Within this work two key aspects have been covered: First, analytical TEM (transmission electron microscopy) investigations were carried out to get insight into novel magnetic materials with high detail. Second, new analytical and imaging possibilities enabled with the commissioning of the new ASTEM (Austrian scanning transmission electron microscope) were explored. The aberration corrected TITAN® microscope (© FEI Company) allows resolving features in scanning transmission mode (STEM) with 70 pm distance. Thereby, direct imaging of light elements in STEM mode by using the annular bright field method becomes possible. Facilitated through high beam currents within the electron probe, an increased acquisition speed of analytical signals is possible. For energy dispersive X-ray spectroscopy (EDXS) a new four detector disc geometry around the specimen was implemented, which increases the accessible collection angle. With the integration of the latest generation of image filter and electron spectrometer (GIF QuantumERS), electron energy loss spectroscopy (EELS) is boosted through the high acquisition speed and the dual spectroscopy mode. The high acquisition speed allows to record up to 1000 spectra per second and the possibility to record atomically resolved EELS maps is at hand. Hereby it is important to avoid beam damage and alteration of the material during imaging and analysis. With the simultaneous acquisition of the low and the high loss spectral region, an extended range for

  18. Trends in nanoscale mechanics mechanics of carbon nanotubes, graphene, nanocomposites and molecular dynamics

    CERN Document Server

    2014-01-01

    This book contains a collection of the state-of-the-art reviews written by the leading researchers in the areas of nanoscale mechanics, molecular dynamics, nanoscale modeling of nanocomposites and mechanics of carbon nanotubes. No other book has reviews of the recent discoveries such as a nanoscale analog of the Pauli’s principle, i.e., effect of the spatial exclusion of electrons or the SEE effect, a new Registry Matrix Analysis for the nanoscale interfacial sliding and new data on the effective viscosity of interfacial electrons in nanoscale stiction at the interfaces. This volume is also an exceptional resource on the well tested nanoscale modeling of carbon nanotubes and nanocomposites, new nanoscale effects, unique evaluations of the effective thickness of carbon nanotubes under different loads, new data on which size of carbon nanotubes is safer and many other topics. Extensive bibliography concerning all these topics is included along with the lucid short reviews. Numerous illustrations are provided...

  19. Toxicity of inhaled 239PuO2 in Beagle dogs. A. Monodisperse 0.75 μm AD particles. B. Monodisperse 1.5 μm AD particles. C. Monodisperse 3.0 μm AD particles. II

    International Nuclear Information System (INIS)

    Muggenburg, B.A.; Guilmette, R.A.; Hahn, F.F.; McClellan, R.O.; Mauderly, J.L.; Mewhinney, J.A.; Pickrell, J.A.; Boecker, B.B.

    1978-01-01

    Studies on the metabolism, dosimetry and biological effects of inhaled particles of 239 PuO 2 have been initiated in Beagle dogs. To obtain information on the relative importance of homogeneity of radiation doses to the lung, dogs have been exposed to particles of monodisperse aerosols (sigma/sub g/ 239 PuO 2 ; 40 dogs to the 0.75 μm AD particles, 72 dogs to the 1.5 μm AD particles and 60 dogs to the 3.0 μm AD particles. The exposures have resulted in graded ILB's, which range from 0.0002 to 2.6 μCi/kg body weight. Twenty-nine dogs were exposed to the aerosol diluent and serve as controls. Five dogs have died 336 to 561 days after exposure in the 1.5 μm AD study. Four dogs have died 116 to 589 days after exposure in the 3.0 μm AD study. These dogs had radiation pneumonitis and pulmonary fibrosis at death. The remaining dogs have survived up to 634 days after exposure. It is anticipated that the other dogs planned for these studies will be exposed over the next 12 months

  20. Toxicity of inhaled 239PuO2 in Beagle dogs. A. Monodisperse 0.75 μm AMAD particles. B. Monodisperse 1.5 μm AMAD particles. C. Monodisperse 3.0 μm AMAD particles. V

    International Nuclear Information System (INIS)

    Muggenburg, B.A.; Guilmette, R.A.; Hahn, F.F.; Boecker, B.B.; McClellan, R.O.; Mauderly, J.L.; Pickrell, J.A.

    1982-01-01

    Studies on the metabolism, dosimetry and biological effects of inhaled particles of 239 PuO 2 in Beagle dogs are in progress. To obtain information on the relative importance of homogeneity versus nonhomogeneity of radiation doses to the lung, dogs have been exposed to monodisperse aerosols of 239 PuO 2 of 0.75, 1.5 or 3.0 μm activity median aerodynamic diameter (AMAD). The exposures have resulted in graded initial lung burdens ranging from 0.0002 to 2.6 μCi 239 Pu per kilogram body weight. Other dogs were exposed to the aerosol diluent to serve as controls. Ten dogs have died in the study with 0.75 μm AMAD particles, 40 dogs have died in the study with 1.5 μm AMAD particles and 35 dogs have died in the study with 3.0 μm AMAD particles of 239 PuO 2 . Dogs have died with radiation pneumonitis and pulmonary fibrosis and carcinomas of the lung. The remaining dogs have survived up to 2100 days after inhalation exposure and are being observed for the remainder of their life span

  1. Toxicity of inhaled 239PuO2 in Beagle dogs: A. Monodisperse 0.75-μm AMAD particles. B. Monodisperse 1.5-μm AMAD particles. C. Monodisperse 3.0--μm AMAD particles. XI

    International Nuclear Information System (INIS)

    Muggenburg, B.A.; Guilmette, R.A.; Hahn, F.F.; Boecker, B.B.; McClellan, R.O.

    1988-01-01

    Beagle dogs were exposed to monodisperse aerosols of 239 PuO 2 of 0.75, 1.5, or 30 μm activity median aerodynamic diameter (AMAD) to obtain information on the relative importance of homogeneity of alpha irradiation doses to the lung in producing biological effects. The dogs' initial pulmonary burdens (IPB) ranged from 0.0002-2.0 μCi (0.0074 to 74 kBq) 239 Pu/kg of body mass. Thirty-six dogs were exposed to the aerosol diluent as controls. Forty-two of 48 dogs exposed to 0.75 μm AMAD particles have died; 67 of 96 have died in the study involving 1.5 μm AMAD particles; and 62 of 72 have died in the study involving the 3.0 μm AMAD particles. Seven of 36 control dogs have died. Most dogs exposed to 239 Pu that have failed to survive have died with radiation pneumonitis and fibrosis and/or lung cancer. Surviving dogs have lived up to 4300 days after exposure. The data obtained to date indicate that the degree of uniformity of dose to the lung does not significantly modify the risk of lung cancer. (author)

  2. EDITORIAL: Big science at the nanoscale Big science at the nanoscale

    Science.gov (United States)

    Reed, Mark

    2009-10-01

    In 1990, the journal Nanotechnology was the first academic publication dedicated to disseminating the results of research in what was then a new field of scientific endeavour. To celebrate the 20th volume of Nanotechnology, we are publishing a special issue of top research papers covering all aspects of this multidisciplinary science, including biology, electronics and photonics, quantum phenomena, sensing and actuating, patterning and fabrication, material synthesis and the properties of nanomaterials. In the early 1980s, scanning probe microscopes brought the concepts of matter and interactions at the nanoscale into visual reality, and hastened a flurry of activity in the burgeoning new field of nanoscience. Twenty years on and nanotechnology has truly come of age. The ramifications are pervasive throughout daily life in communication, health care and entertainment technology. For example, DVDs have now consigned videotapes to the ark and mobile phones are as prevalent as house keys, and these technologies already look set to be superseded by internet phones and Blu-Ray discs. Nanotechnology has been in the unique position of following the explosive growth of this discipline from its outset. The surge of activity in the field is notable in the number of papers published by the journal each year, which has skyrocketed. The journal is now published weekly, publishing over 1400 articles a year. What is more, the quality of these articles is also constantly improving; the average number of citations to articles within two years of publication, quantified by the ISI impact factor, continues to increase every year. The rate of activity in the field shows no signs of slowing down, as is evident from the wealth of great research published each week. The aim of the 20th volume special issue is to present some of the very best and most recent research in many of the wide-ranging fields covered by the journal, a celebration of the present state of play in nanotechnology and

  3. EDITORIAL: Mastering matter at the nanoscale Mastering matter at the nanoscale

    Science.gov (United States)

    Forchel, Alfred

    2009-10-01

    In the early 1980s, the development of scanning probe techniques gave scientists a titillating view of surfaces with nanometre resolution, igniting activity in research at the nanoscale. Images at unprecedented resolution were unveiled with the aid of various types of nanosized tips, including the scanning tunnelling (Binnig G, Rohrer H, Gerber C and Weibel E 1982 Appl. Phys. Lett. 40 178-80) the atomic force (Binnig G, Quate C F and Gerber C 1986 Phys. Rev. Lett. 56 930-3) and the near-field scanning microscopes (Dürig U, Pohl D W and Rohner F 1986 J. Appl. Phys. 59 3318-27). From the magnitude of tunnelling currents between conductive surfaces and van der Waals forces between dielectrics to the non-propagating evanescent fields at illuminated surfaces, a range of signal responses were harnessed enabling conductive, dielectric and even biological systems to be imaged. But it may be argued that it was the ability to manipulate matter at the nanoscale that really empowered nanotechnology. From the inception of the scanning probe revolution, these probes used to image nanostructures were also discovered to be remarkable tools for the manipulation of nanoparticles. Insights into the mechanism behind such processes were reported by a team of researchers at UCLA over ten years ago in 1998 (Baur C et al 1998 Nanotechnology 9 360-4). In addition, lithography and etching methods of patterning continue to evolve into ever more sophisticated techniques for exerting design over the structure of matter at the nanoscale. These so-called top-down methods, such as photolithography, electron-beam lithography and nanoimprint lithography, now provide control over features with a resolution of a few nanometres. Bottom-up fabrication techniques that exploit the self-assembly of constituents into desired structures have also stimulated extensive research. These techniques, such as the electrochemically assembled quantum-dot arrays reported by a team of US reasearchers over ten years

  4. Energy efficiency in nanoscale synthesis using nanosecond plasmas.

    Science.gov (United States)

    Pai, David Z; Ken Ostrikov, Kostya; Kumar, Shailesh; Lacoste, Deanna A; Levchenko, Igor; Laux, Christophe O

    2013-01-01

    We report a nanoscale synthesis technique using nanosecond-duration plasma discharges. Voltage pulses 12.5 kV in amplitude and 40 ns in duration were applied repetitively at 30 kHz across molybdenum electrodes in open ambient air, generating a nanosecond spark discharge that synthesized well-defined MoO₃ nanoscale architectures (i.e. flakes, dots, walls, porous networks) upon polyamide and copper substrates. No nitrides were formed. The energy cost was as low as 75 eV per atom incorporated into a nanostructure, suggesting a dramatic reduction compared to other techniques using atmospheric pressure plasmas. These findings show that highly efficient synthesis at atmospheric pressure without catalysts or external substrate heating can be achieved in a simple fashion using nanosecond discharges.

  5. Common Principles of Molecular Electronics and Nanoscale Electrochemistry.

    Science.gov (United States)

    Bueno, Paulo Roberto

    2018-05-24

    The merging of nanoscale electronics and electrochemistry can potentially modernize the way electronic devices are currently engineered or constructed. It is well known that the greatest challenges will involve not only miniaturizing and improving the performance of mobile devices, but also manufacturing reliable electrical vehicles, and engineering more efficient solar panels and energy storage systems. These are just a few examples of how technological innovation is dependent on both electrochemical and electronic elements. This paper offers a conceptual discussion of this central topic, with particular focus on the impact that uniting physical and chemical concepts at a nanoscale could have on the future development of electroanalytical devices. The specific example to which this article refers pertains to molecular diagnostics, i.e., devices that employ physical and electrochemical concepts to diagnose diseases.

  6. Nanoscale and submicron fatigue crack growth in nickel microbeams

    International Nuclear Information System (INIS)

    Yang, Y.; Yao, N.; Imasogie, B.; Soboyejo, W.O.

    2007-01-01

    This paper presents a novel edge-notched microbeam technique for the study of short fatigue crack growth. The technique is used to study submicron and nanoscale fatigue in LIGA Ni thin films with columnar microstructures. The edge-notched microbeams were fabricated within LIGA Ni thin films, using focused ion beam (FIB) techniques. The microbeams were then cyclically deformed to failure at a stress ratio of 0.1. Different slip-band structures were observed below the nanoscale notches. Cyclic deformation resulted in the formation of primary slip bands below the notch. Subsequent crack growth then occurred by the unzipping of fatigue cracks along intersecting slip bands. The effects of the primary slip bands were idealized using dislocation-based models. These were used to estimate the intrinsic fatigue threshold and the fatigue endurance limit. The estimates from the model are shown to be consistent with experimental data from prior stress-life experiments and current/prior fatigue threshold estimates

  7. Nanoscale synthesis and characterization of graphene-based objects

    Directory of Open Access Journals (Sweden)

    Daisuke Fujita

    2011-01-01

    Full Text Available Graphene-based nano-objects such as nanotrenches, nanowires, nanobelts and nanoscale superstructures have been grown by surface segregation and precipitation on carbon-doped mono- and polycrystalline nickel substrates in ultrahigh vacuum. The dominant morphologies of the nano-objects were nanowire and nanosheet. Nucleation of graphene sheets occurred at surface defects such as step edges and resulted in the directional growth of nanowires. Surface analysis by scanning tunneling microscopy (STM has clarified the structure and functionality of the novel nano-objects at atomic resolution. Nanobelts were detected consisting of bilayer graphene sheets with a nanoscale width and a length of several microns. Moiré patterns and one-dimensional reconstruction were observed on multilayer graphite terraces. As a useful functionality, application to repairable high-resolution STM probes is demonstrated.

  8. Highly repeatable nanoscale phase coexistence in vanadium dioxide films

    Science.gov (United States)

    Huffman, T. J.; Lahneman, D. J.; Wang, S. L.; Slusar, T.; Kim, Bong-Jun; Kim, Hyun-Tak; Qazilbash, M. M.

    2018-02-01

    It is generally believed that in first-order phase transitions in materials with imperfections, the formation of phase domains must be affected to some extent by stochastic (probabilistic) processes. The stochasticity would lead to unreliable performance in nanoscale devices that have the potential to exploit the transformation of physical properties in a phase transition. Here we show that stochasticity at nanometer length scales is completely suppressed in the thermally driven metal-insulator transition (MIT) in sputtered vanadium dioxide (V O2 ) films. The nucleation and growth of domain patterns of metallic and insulating phases occur in a strikingly reproducible way. The completely deterministic nature of domain formation and growth in films with imperfections is a fundamental and unexpected finding about the kinetics of this material. Moreover, it opens the door for realizing reliable nanoscale devices based on the MIT in V O2 and similar phase-change materials.

  9. Brillouin gain enhancement in nano-scale photonic waveguide

    Science.gov (United States)

    Nouri Jouybari, Soodabeh

    2018-05-01

    The enhancement of stimulated Brillouin scattering in nano-scale waveguides has a great contribution in the improvement of the photonic devices technology. The key factors in Brillouin gain are the electrostriction force and radiation pressure generated by optical waves in the waveguide. In this article, we have proposed a new scheme of nano-scale waveguide in which the Brillouin gain is considerably improved compared to the previously-reported schemes. The role of radiation pressure in the Brillouin gain was much higher than the role of the electrostriction force. The Brillouin gain strongly depends on the structural parameters of the waveguide and the maximum value of 12127 W-1 m-1 is obtained for the Brillouin gain.

  10. Nanoscale semiconducting silicon as a nutritional food additive

    International Nuclear Information System (INIS)

    Canham, L T

    2007-01-01

    Very high surface area silicon powders can be realized by high energy milling or electrochemical etching techniques. Such nanoscale silicon structures, whilst biodegradable in the human gastrointestinal tract, are shown to be remarkably stable in most foodstuffs and beverages. The potential for using silicon to improve the shelf life and bioavailability of specific nutrients in functional foods is highlighted. Published drug delivery data implies that the nanoentrapment of hydrophobic nutrients will significantly improve their dissolution kinetics, through a combined effect of nanostructuring and solid state modification. Nutrients loaded to date include vitamins, fish oils, lycopene and coenzyme Q10. In addition, there is growing published evidence that optimized release of orthosilicic acid, the biodegradation product of semiconducting silicon in the gut, offers beneficial effects with regard bone health. The utility of nanoscale silicon in the nutritional field shows early promise and is worthy of much further study

  11. Modeling of nanoscale liquid mixture transport by density functional hydrodynamics

    Science.gov (United States)

    Dinariev, Oleg Yu.; Evseev, Nikolay V.

    2017-06-01

    Modeling of multiphase compositional hydrodynamics at nanoscale is performed by means of density functional hydrodynamics (DFH). DFH is the method based on density functional theory and continuum mechanics. This method has been developed by the authors over 20 years and used for modeling in various multiphase hydrodynamic applications. In this paper, DFH was further extended to encompass phenomena inherent in liquids at nanoscale. The new DFH extension is based on the introduction of external potentials for chemical components. These potentials are localized in the vicinity of solid surfaces and take account of the van der Waals forces. A set of numerical examples, including disjoining pressure, film precursors, anomalous rheology, liquid in contact with heterogeneous surface, capillary condensation, and forward and reverse osmosis, is presented to demonstrate modeling capabilities.

  12. Ion concentration in micro and nanoscale electrospray emitters.

    Science.gov (United States)

    Yuill, Elizabeth M; Baker, Lane A

    2018-06-01

    Solution-phase ion transport during electrospray has been characterized for nanopipettes, or glass capillaries pulled to nanoscale tip dimensions, and micron-sized electrospray ionization emitters. Direct visualization of charged fluorophores during the electrospray process is used to evaluate impacts of emitter size, ionic strength, analyte size, and pressure-driven flow on heterogeneous ion transport during electrospray. Mass spectrometric measurements of positively- and negatively-charged proteins were taken for micron-sized and nanopipette emitters under low ionic strength conditions to further illustrate a discrepancy in solution-driven transport of charged analytes. A fundamental understanding of analyte electromigration during electrospray, which is not always considered, is expected to provide control over selective analyte depletion and enrichment, and can be harnessed for sample cleanup. Graphical abstract Fluorescence micrographs of ion migration in nanoscale pipettes while solution is electrosprayed.

  13. Nanoscale semiconducting silicon as a nutritional food additive

    Energy Technology Data Exchange (ETDEWEB)

    Canham, L T [pSiNutria Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ (United Kingdom)

    2007-05-09

    Very high surface area silicon powders can be realized by high energy milling or electrochemical etching techniques. Such nanoscale silicon structures, whilst biodegradable in the human gastrointestinal tract, are shown to be remarkably stable in most foodstuffs and beverages. The potential for using silicon to improve the shelf life and bioavailability of specific nutrients in functional foods is highlighted. Published drug delivery data implies that the nanoentrapment of hydrophobic nutrients will significantly improve their dissolution kinetics, through a combined effect of nanostructuring and solid state modification. Nutrients loaded to date include vitamins, fish oils, lycopene and coenzyme Q10. In addition, there is growing published evidence that optimized release of orthosilicic acid, the biodegradation product of semiconducting silicon in the gut, offers beneficial effects with regard bone health. The utility of nanoscale silicon in the nutritional field shows early promise and is worthy of much further study.

  14. Nanoscale Rheology and Anisotropic Diffusion Using Single Gold Nanorod Probes

    Science.gov (United States)

    Molaei, Mehdi; Atefi, Ehsan; Crocker, John C.

    2018-03-01

    The complex rotational and translational Brownian motion of anisotropic particles depends on their shape and the viscoelasticity of their surroundings. Because of their strong optical scattering and chemical versatility, gold nanorods would seem to provide the ultimate probes of rheology at the nanoscale, but the suitably accurate orientational tracking required to compute rheology has not been demonstrated. Here we image single gold nanorods with a laser-illuminated dark-field microscope and use optical polarization to determine their three-dimensional orientation to better than one degree. We convert the rotational diffusion of single nanorods in viscoelastic polyethylene glycol solutions to rheology and obtain excellent agreement with bulk measurements. Extensions of earlier models of anisotropic translational diffusion to three dimensions and viscoelastic fluids give excellent agreement with the observed motion of single nanorods. We find that nanorod tracking provides a uniquely capable approach to microrheology and provides a powerful tool for probing nanoscale dynamics and structure in a range of soft materials.

  15. Nanoscale roughness contact in a slider-disk interface.

    Science.gov (United States)

    Hua, Wei; Liu, Bo; Yu, Shengkai; Zhou, Weidong

    2009-07-15

    The nanoscale roughness contact between molecularly smooth surfaces of a slider-disk interface in a hard disk drive is analyzed, and the lubricant behavior at very high shear rate is presented. A new contact model is developed to study the nanoscale roughness contact behavior by classifying various forms of contact into slider-lubricant contact, slider-disk elastic contact and plastic contact. The contact pressure and the contact probabilities of the three types of contact are investigated. The new contact model is employed to explain and provide insight to an interesting experimental result found in a thermal protrusion slider. The protrusion budget for head surfing in the lubricant, which is the ideal state for contact recording, is also discussed.

  16. Nanoscale roughness contact in a slider-disk interface

    International Nuclear Information System (INIS)

    Hua Wei; Liu Bo; Yu Shengkai; Zhou Weidong

    2009-01-01

    The nanoscale roughness contact between molecularly smooth surfaces of a slider-disk interface in a hard disk drive is analyzed, and the lubricant behavior at very high shear rate is presented. A new contact model is developed to study the nanoscale roughness contact behavior by classifying various forms of contact into slider-lubricant contact, slider-disk elastic contact and plastic contact. The contact pressure and the contact probabilities of the three types of contact are investigated. The new contact model is employed to explain and provide insight to an interesting experimental result found in a thermal protrusion slider. The protrusion budget for head surfing in the lubricant, which is the ideal state for contact recording, is also discussed.

  17. Negative pressure characteristics of an evaporating meniscus at nanoscale

    Directory of Open Access Journals (Sweden)

    Maroo Shalabh

    2011-01-01

    Full Text Available Abstract This study aims at understanding the characteristics of negative liquid pressures at the nanoscale using molecular dynamics simulation. A nano-meniscus is formed by placing liquid argon on a platinum wall between two nano-channels filled with the same liquid. Evaporation is simulated in the meniscus by increasing the temperature of the platinum wall for two different cases. Non-evaporating films are obtained at the center of the meniscus. The liquid film in the non-evaporating and adjacent regions is found to be under high absolute negative pressures. Cavitation cannot occur in these regions as the capillary height is smaller than the critical cavitation radius. Factors which determine the critical film thickness for rupture are discussed. Thus, high negative liquid pressures can be stable at the nanoscale, and utilized to create passive pumping devices as well as significantly enhance heat transfer rates.

  18. Adhesion Dynamics in Probing Micro- and Nanoscale Thin Solid Films

    Directory of Open Access Journals (Sweden)

    Xiaoling He

    2008-01-01

    Full Text Available This study focuses on modeling the probe dynamics in scratching and indenting thin solid films at micro- and nanoscales. The model identifies bifurcation conditions that define the stick-slip oscillation patterns of the tip. It is found that the local energy fluctuations as a function of the inelastic deformation, defect formation, material properties, and contact parameters determine the oscillation behavior. The transient variation of the localized function makes the response nonlinear at the adhesion junction. By quantifying the relation between the bifurcation parameters and the oscillation behavior, this model gives a realistic representation of the complex adhesion dynamics. Specifically, the model establishes the link between the stick-slip behavior and the inelastic deformation and the local potentials. This model justifies the experimental observations and the molecular dynamics simulation of the adhesion and friction dynamics in both the micro- and nanoscale contact.

  19. Magnetic field processing of inorganic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kunerth, D.C.; Peterson, E.S. [Idaho National Engineering Laboratory, Idaho Falls, ID (United States)

    1995-05-01

    The purpose of this project is to investigate, understand, and demonstrate the use of magnetic field processing (MFP) to modify the properties of inorganic-based polymers and to develop the basic technical knowledge required for industrial implementation. Polyphosphazene membranes for chemical separation applications are being emphasized by this project. Previous work demonstrated that magnetic fields, appropriately applied during processing, can be used to beneficially modify membrane morphology. MFP membranes have significantly increased flux capabilities while maintaining the same chemical selectivity as the unprocessed membranes.

  20. Studies on inorganic exchangers - polyantimonic acid

    International Nuclear Information System (INIS)

    Murthy, T.S.; Balasubramanian, K.R.; Ananthakrishnan, M.; Ramani, K.S.; Varma, R.N.

    1976-01-01

    From the detailed experimental investigations carried out, it may be mentioned that the inorganic exchanger polyantimonic acid could be used for effectively separating strontium from fission product waste solutions free from caesium and zirconium at acidities of the order of 2M or so. After thorough washing of the column with 2M HNO 3 acid to remove any residual activity unadsorbed, the strontium can be eluted with a mixture of 1M AgNO 3 +6M HNO 3 at room temperature. The column after regeneration and conditioning can be used for further adsorption and elution up to a maximum of 6 cycles without much deterioration in column characteristics. (author)