Boron-doped nanocrystalline diamond microelectrode arrays monitor cardiac action potentials.

Science.gov (United States)

Maybeck, Vanessa; Edgington, Robert; Bongrain, Alexandre; Welch, Joseph O; Scorsone, Emanuel; Bergonzo, Philippe; Jackman, Richard B; Offenhäusser, Andreas

2014-02-01

The expansion of diamond-based electronics in the area of biological interfacing has not been as thoroughly explored as applications in electrochemical sensing. However, the biocompatibility of diamond, large safe electrochemical window, stability, and tunable electronic properties provide opportunities to develop new devices for interfacing with electrogenic cells. Here, the fabrication of microelectrode arrays (MEAs) with boron-doped nanocrystalline diamond (BNCD) electrodes and their interfacing with cardiomyocyte-like HL-1 cells to detect cardiac action potentials are presented. A nonreductive means of structuring doped and undoped diamond on the same substrate is shown. The resulting BNCD electrodes show high stability under mechanical stress generated by the cells. It is shown that by fabricating the entire surface of the MEA with NCD, in patterns of conductive doped, and isolating undoped regions, signal detection may be improved up to four-fold over BNCD electrodes passivated with traditional isolators. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of cadmium doped lead–borate ...

Indian Academy of Sciences (India)

Unknown

Mater. Sci., Vol. 29, No. 1, February 2006, pp. 55–58. © Indian Academy of Sciences. 55. Synthesis and characterization of cadmium doped lead–borate glasses. A A ALEMI*, H SEDGHI†, A R MIRMOHSENI and V GOLSANAMLU. Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.

Development of Nano-crystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases

Energy Technology Data Exchange (ETDEWEB)

Xiao, Hai [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States); Lin, Jerry [Arizona State Univ., Tempe, AZ (United States); Romero, Van [New Mexico Institute of Mining and Technology, Socorro, NM (United States)

2012-03-01

This is a final technical report for the first project year from July 1, 2005 to Jan 31, 2012 for DoE/NETL funded project DE-FC26-05NT42439: Development of Nanocrystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases. This report summarizes the technical progresses and achievements towards the development of novel nanocrystalline doped ceramic material-enabled optical fiber sensors for in situ and real time monitoring the gas composition of flue or hot gas streams involved in fossil-fuel based power generation and hydrogen production.

The Formation of Lithiated Ti-Doped {alpha}-Fe{sub 2}O{sub 3} Nanocrystalline Particles by Mechanical Milling of Ti-Doped Lithium Spinel Ferrite

Energy Technology Data Exchange (ETDEWEB)

Widatallah, H. M., E-mail: hisham@ictp.trieste.it [Khartoum University, Department of Physics (Sudan); Gismelseed, A. M.; Bouziane, K. [Sultan Qaboos University, Department of Physics (Oman); Berry, F. J. [Open University, Department of Chemistry (United Kingdom); Al Rawas, A. D.; Al-Omari, I. A.; Yousif, A. A.; Elzain, M. E. [Sultan Qaboos University, Department of Physics (Oman)

2004-12-15

The milling of spinel-related Ti-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} for different times is studied with XRD, Moessbauer spectroscopy and magnetic measurements. Milling converts the material to Li-Ti-doped {alpha}-Fe{sub 2}O{sub 3} nanocrystalline particles via an intermediate {gamma}-LiFeO{sub 2}-related phase. The role played by the dopant Ti-ion in the process is emphasized.

Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

Directory of Open Access Journals (Sweden)

Milos Nesladek, Jiri J. Mares, Dominique Tromson, Christine Mer, Philippe Bergonzo, Pavel Hubik and Jozef Kristofik

2006-01-01

Full Text Available In this work, we report on superconductivity (SC found in thin B-doped nanocrystalline diamond films, prepared by the PE-CVD technique. The thickness of the films varies from about 100 to 400 nm, the films are grown on low-alkaline glass at substrate temperatures of about 500–700 °C. The SIMS measurements show that films can be heavily doped with boron in concentrations in the range of 3×1021 cm−3. The Raman spectra show Fano resonances, confirming the substitutional B-incorporation. The low temperature magnetotransport measurements reveal a positive magnetoresistance. The SC transition is observed at about Tc=1.66 K. A simple theory exploiting the concept of weak localization accounting for this transition is proposed.

Effect of cadmium doping on some properties of glass-insulated bismuth-based microwires

International Nuclear Information System (INIS)

Meglei, D.; Dyntu, M.

2011-01-01

Full text: According to the literature, semiconductor converters based on films and wire crystals are widely used in present-day microelectronics. However, the production of efficient semiconductor converters requires crystals of high structural perfection with a given composition and desired electrical and mechanical properties. In this work, we describe the study of the perfection of the microstructure and mechanical properties of glass-insulated microwires based on Bi doped with cadmium (Cd) and the technique of preparation of micro resistors suitable for instrumentation applications. Microscopic studies of ground, polished, and chemically etched microwires doped with cadmium showed that they have smooth cylindrical surfaces in the entire range of diameters. Sizes of defects in the form of micropores, microcracks, dislocations, and twins on their surface are much smaller than those of pure bismuth microwire. It is also found that the tendency to twinning and the number and size of surface defects decrease with decreasing diameters; at the same time, their homogeneity increases. The tensile strength of the studied microwires with glass insulation is high for all tested diameters and ranges within 33.274.1 kg/mm with respect to internal diameters of 5.6 21.2 m; in addition, they withstand a breaking force up to 130 g and more, whereas the samples of pure bismuth microwires withstood a force up to 80 g. It is also found that the tensile strength of cadmium doped microwires is significantly higher than that of undoped samples. The bending strength as a measure of elasticity was determined using a special installation according to the critical bending radius of the sample at which the sample integrity is violated. The results of bending tests showed that, with increasing diameter of the doped samples, the critical radius linearly increases; that is, in this case, the elasticity increases with decreasing diameter. Metallographic analysis revealed that cadmium in the

Increased charge storage capacity of titanium nitride electrodes by deposition of boron-doped nanocrystalline diamond films

DEFF Research Database (Denmark)

Meijs, Suzan; McDonald, Matthew; Sørensen, Søren

2015-01-01

The aim of this study was to investigate the feasibility of depositing a thin layer of boron-doped nanocrystalline diamond (B-NCD) on titanium nitride (TiN) coated electrodes and the effect this has on charge injection properties. The charge storage capacity increased by applying the B-NCD film...

Alcohol vapor sensing by cadmium-doped zinc oxide thick films based chemical sensor

Science.gov (United States)

Zargar, R. A.; Arora, M.; Chackrabarti, S.; Ahmad, S.; Kumar, J.; Hafiz, A. K.

2016-04-01

Cadmium-doped zinc oxide nanoparticles were derived by simple chemical co-precipitation route using zinc acetate dihydrate and cadmium acetate dihydrate as precursor materials. The thick films were casted from chemical co-precipitation route prepared nanoparticles by economic facile screen printing method. The structural, morphological, optical and electrical properties of the film were characterized relevant to alcohol vapor sensing application by powder XRD, SEM, UV-VIS and DC conductivity techniques. The response and sensitivity of alcohol (ethanol) vapor sensor are obtained from the recovery curves at optimum working temperature range from 20∘C to 50∘C. The result shows that maximum sensitivity of the sensor is observed at 25∘C operating temperature. On varying alcohol vapor concentration, minor variation in resistance has been observed. The sensing mechanism of sensor has been described in terms of physical adsorption and chemical absorption of alcohol vapors on cadmium-doped zinc oxide film surface and inside film lattice network through weak hydrogen bonding, respectively.

Electrical properties of cadmium telluride films doped with antimony

International Nuclear Information System (INIS)

Atdaev, B.S.; Garyagdyev, G.; Grin', V.F.; Noskov, A.I.

1989-01-01

Effect of cadmium telluride doping with antimony on electric and photoelectric properties is investigated. Temperature dependence of dark (σ d ) and photoconductivity (σ p ) during excitation from the range of proper absorption in the temperature range 77-300 K and spectral distribution of photoconductivity at 300 K are investigated. It is shown that in the process of doping antimony diffusses intensively over CdTe grain boundaries, decreasing potential barriers between them and due to diffusion into CdTe grains it changes their electrical properties. The acceptor character of antimony impurity can be caused by antimony diffusion into tellurium sublattice owing to proximity of their ionic and covalent radii

Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

Directory of Open Access Journals (Sweden)

Carmen Steluta Ciobanu

2012-01-01

Full Text Available The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO46(OH2 with 0≤x≤0.2 nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic 5D0→7F0 transition observed at 578 nm related to Eu3+ ions distributed on Ca2+ sites of the apatitic structure.

Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

International Nuclear Information System (INIS)

Ciobanu, C.S.; Iconaru, S.L.; Predoi, D.; Massuyeau, F.; Constantin, L.V.; Costescu, A.

2012-01-01

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca 10-x Eu x (PO 4 ) 6 (OH) 2 ) with 0>x>0.2 nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic 5 D 0 → 7 F 0 transition observed at 578 nm related to Eu 3+ ions distributed on Ca 2+ sites of the apatitic structure

Preparation of cadmium-doped ZnO thin films by SILAR and their ...

Indian Academy of Sciences (India)

Cadmium-doped zinc oxide (Cd : ZnO) thin films were deposited from sodium zincate bath .... of complex ion on the substrate followed by reaction of the .... Intensity (a.u.). 0. 500 .... trum confirmed the presence of Zn, O and Cd elements in the.

Synthesis and properties of nickel-doped nanocrystalline barium hexaferrite ceramic materials

Science.gov (United States)

Waqar, Moaz; Rafiq, Muhammad Asif; Mirza, Talha Ahmed; Khalid, Fazal Ahmad; Khaliq, Abdul; Anwar, Muhammad Sabieh; Saleem, Murtaza

2018-04-01

M-type barium hexaferrite ceramics have emerged as important materials both for technological and commercial applications. However, limited work has been reported regarding the investigation of nanocrystalline Ni-doped barium hexaferrites. In this study, nanocrystalline barium hexaferrite ceramics with the composition BaFe12- x Ni x O19 (where x = 0, 0.3 and 0.5) were synthesized by sol-gel method and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and precision impedance analyzer. All the synthesized samples had single magnetoplumbite phase having space group P63/mmc showing the successful substitution of Ni in BaFe12O19 without the formation of any impurity phase. Average grain size of undoped samples was around 120 nm which increased slightly with the addition of Ni. Saturation magnetization ( M s) and remnant magnetization ( M r) increased with the addition of Ni, however, coercivity ( H c) decreased with the increase in Ni from x = 0 to x = 0.5. Real and imaginary parts of permittivity decreased with the increasing frequency and increased with Ni content. Dielectric loss and conductivity showed slight variation with the increase in Ni concentration.

Structure and properties of YBa2Cu3O7-δ superconductor doped with bulk cadmium oxide

Directory of Open Access Journals (Sweden)

A Echresh

2010-09-01

Full Text Available In this paper, the Y1-xCdxBa2Cu3O7-δ superconductor with x=0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5 are prepared using the solid state method and the structure, electrical resistance, critical current density and critical temperature of it, have been studied. The results show that these doping do not affect so much on the structure and lattice parameters. The electrical resistance of samples increased with doping. A little amount of doping cadmium improve critical current density such that the sample x=0.1 has a maximum critical current density among the samples. The critical temperature with doping cadmium up to x=0.2 has little fluctuation and its variation can be ignored, but by increasing up to x=0.5 the critical temperature decreases gradually.

Boron Doped Nanocrystalline Diamond Films for Biosensing Applications

Directory of Open Access Journals (Sweden)

V. Petrák

2011-01-01

Full Text Available With the rise of antibiotic resistance of pathogenic bacteria there is an increased demand for monitoring the functionality of bacteria membranes, the disruption of which can be induced by peptide-lipid interactions. In this work we attempt to construct and disrupt supported lipid membranes (SLB on boron doped nanocrystalline diamond (B-NCD. Electrochemical Impedance Spectroscopy (EIS was used to study in situ changes related to lipid membrane formation and disruption by peptide-induced interactions. The observed impedance changes were minimal for oxidized B-NCD samples, but were still detectable in the low frequency part of the spectra. The sensitivity for the detection of membrane formation and disruption was significantly higher for hydrogenated B-NCD surfaces. Data modeling indicates large changes in the electrical charge when an electrical double layer is formed at the B-NCD/SLB interface, governed by ion absorption. By contrast, for oxidized B-NCD surfaces, these changes are negligible indicating little or no change in the surface band bending profile.

Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

DEFF Research Database (Denmark)

Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

2016-01-01

Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...... is a good candidate for improving the overall conversion efficiencies in oxide thermoelectric modules. Meanwhile, Sc-doped ZnCdO is robust in air at high temperatures, whereas other n-type materials, such as Al-doped ZnO, will experience rapid degradation of their electrical conductivity and ZT....

Atomistic modeling of La3+ doping segregation effect on nanocrystalline yttria-stabilized zirconia.

Science.gov (United States)

Zhang, Shenli; Sha, Haoyan; Castro, Ricardo H R; Faller, Roland

2018-05-16

The effect of La3+ doping on the structure and ionic conductivity change in nanocrystalline yttria-stabilized zirconia (YSZ) was studied using a combination of Monte Carlo and molecular dynamics simulations. The simulation revealed the segregation of La3+ at eight tilt grain boundary (GB) structures and predicted an average grain boundary (GB) energy decrease of 0.25 J m-2, which is close to the experimental values reported in the literature. Cation stabilization was found to be the main reason for the GB energy decrease, and energy fluctuations near the grain boundary are smoothed out with La3+ segregation. Both dynamic and energetic analysis on the Σ13(510)/[001] GB structure revealed La3+ doping hinders O2- diffusion in the GB region, where the diffusion coefficient monotonically decreases with increasing La3+ doping concentration. The effect was attributed to the increase in the site-dependent migration barriers for O2- hopping caused by segregated La3+, which also leads to anisotropic diffusion at the GB.

Surface modification of cadmium sulfide thin film honey comb nanostructures: Effect of in situ tin doping using chemical bath deposition

Energy Technology Data Exchange (ETDEWEB)

Wilson, K.C., E-mail: wilsonphy@gmail.com [Department of Physics, Govt. Polytechnic College Kothamangalam, Chelad P O, Ernakulam, Kerala 686681 (India); Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India); Basheer Ahamed, M. [Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India)

2016-01-15

Graphical abstract: - Highlights: • Novel honey comb like cadmium sulfide thin film nanostructures prepared using chemical bath deposition on glass substrates. • Honey comb nanostructure found in two layers: an ultra thin film at bottom and well inter connected with walls of < 25 nm thick on top; hence maximum surface area possible for CdS nanostructure. • Shell size of the nanostructures and energy band gaps were controlled also an enhanced persistent conductivity observed on Sn doping. - Abstract: Even though nanostructures possess large surface to volume ratio compared to their thin film counterpart, the complicated procedure that demands for the deposition on a substrate kept them back foot in device fabrication techniques. In this work, a honey comb like cadmium sulfide (CdS) thin films nanostructure are deposited on glass substrates using simple chemical bath deposition technique at 65 °C. Energy band gaps, film thickness and shell size of the honey comb nanostructures are successfully controlled using tin (Sn) doping and number of shells per unit area is found to be maximum for 5% Sn doped (in the reaction mixture) sample. X-ray diffraction and optical absorption analysis showed that cadmium sulfide and cadmium hydroxide coexist in the samples. TEM measurements showed that CdS nanostructures are embedded in cadmium hydroxide just like “plum pudding”. Persistent photoconductivity measurements of the samples are also carried out. The decay constants found to be increased with increases in Sn doping.

Influence of texture coefficient on surface morphology and sensing properties of W-doped nanocrystalline tin oxide thin films.

Science.gov (United States)

Kumar, Manjeet; Kumar, Akshay; Abhyankar, A C

2015-02-18

For the first time, a new facile approach based on simple and inexpensive chemical spray pyrolysis (CSP) technique is used to deposit Tungsten (W) doped nanocrystalline SnO2 thin films. The textural, optical, structural and sensing properties are investigated by GAXRD, UV spectroscopy, FESEM, AFM, and home-built sensing setup. The gas sensing results indicate that, as compared to pure SnO2, 1 wt % W-doping improves sensitivity along with better response (roughness values of 3.82 eV and 3.01 nm, respectively. Reduction in texture coefficient along highly dense (110) planes with concomitant increase along loosely packed (200) planes is found to have prominent effect on gas sensing properties of W-doped films.

Theoretical study of bismuth-doped cadmium telluride

Science.gov (United States)

Menendez-Proupin, E.; Rios-Gonzalez, J. A.; Pena, J. L.

Cadmium telluride heavily doped with bismuth has been proposed as an absorber with an intermediate band for solar cells. Increase in the photocurrent has been shown recently, although the overall cell efficiency has not improved. In this work, we study the electronic structure and the formation energies of the defects associated to bismuth impurities. We have performed electronic structure calculations within generalized density functional theory, using the exchange-correlation functional HSE(w) , where the range-separation parameter w has been tuned to reproduce the CdTe bandgap. Improving upon previous reports, we have included the spin-orbit interaction, which modifies the structure of the valence band and the energy levels of bismuth. We have found that interstitial Bi (Bii) tends to occupy Cd vacancies, cadmium substitution (BiCd) creates single donor level, while tellurium substitution (BiTe) is a shallow single acceptor. We investigate the interaction between these point defects and how can they be combined to create a partially filled intermediate band. Supported by FONDECYT Grant 1130437, CONACYT-SENER SUSTENTABILIDAD ENERGETICA/project CeMIE-Sol PY-207450/25 and PY-207450/26. JARG acknowledges CONACYT fellowship for research visit. Powered@NLHPC (ECM-02).

Synthesis and photocatalytic activity of mesoporous nanocrystalline Fe-doped titanium dioxide

KAUST Repository

Qamar, Mohd

2014-07-01

Synthesis of mesoporous nanocrystalline iron-doped titania following the sol-gel method is presented in this work. Samples with various molar ratios (0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10 and 20%) of Fe to Ti were prepared. The particle size was found to be in the range of ∼12 nm while mesopores were approximately near to ∼5.5 nm. The effect of Fe as doping element on titania properties, such as crystallite size, surface area, pore size, pore volume and d-spacing was investigated. Moreover, distribution of Fe in TiO2 matrix was determined by elemental mapping whereas change in absorption properties was evaluated by diffuse reflectance spectroscopy. It was observed that as the Fe content was increased, a partial phase transformation from anatase to rutile and pseudorutile took place. Effect of ultraviolet, ultraviolet-visible and visible radiations on the photocatalytic activity of these catalysts was studied by removal of Methyl Orange as model pollutant. As results, it was found that the photocatalytic activity of such catalysts depends strongly on Fe amount and type of radiation. © 2013 Elsevier B.V.

Resistance to protein adsorption and adhesion of fibroblasts on nanocrystalline diamond films: the role of topography and boron doping

Czech Academy of Sciences Publication Activity Database

Alcaide, M.; Papaioannou, S.; Taylor, Andrew; Fekete, Ladislav; Gurevich, L.; Zachar, V.; Pennisi, C.P.

2016-01-01

Roč. 27, č. 5 (2016), s. 90-1-12 ISSN 0957-4530 R&D Projects: GA MŠk LO1409 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568 Institutional support: RVO:68378271 Keywords : protein adsorption * fibroblasts adhesion * nanocrystalline diamond * boron doping * topography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.325, year: 2016

Doped nanocrystalline ZnO powders for non-linear resistor applications by spray pyrolysis method.

Science.gov (United States)

Hembram, Kaliyan; Vijay, R; Rao, Y S; Rao, T N

2009-07-01

Homogeneous and doped nanocrystalline ZnO powders (30-200 nm) were synthesized by spray pyrolysis technique. The spray pyrolysed powders were calcined in the temperature range of 500-750 degrees C. Formation of insulating pyrochlore phase started from 700 degrees C during the calcination itself. The calcined powders were compacted and sintered at different temperatures ranging from 900-1200 degrees C for 0.5-4 h. The densification behavior was found to be dependent on calcination temperature of the nanopowder. The resulting discs were found to have density (5.34-5.62 g/cc) in the range of 96-99% of theoretical density. The breakdown voltage value obtained for the nanopowder based non-linear resistor is 10.3 kV/cm with low leakage current density of 0.7 microA/cm2 and coefficient of nonlinearity as high as 193. The activation energy for grain growth of the doped ZnO nanopowder powders is 449.4 +/- 15 kJ/mol.

Photocatalytic behaviors and structural characterization of nanocrystalline Fe-doped TiO2 synthesized by mechanical alloying

International Nuclear Information System (INIS)

Kim, Dong Hyun; Hong, Hyun Seon; Kim, Sun Jae; Song, Jae Sung; Lee, Kyung Sub

2004-01-01

Nanocrystalline Fe-doped TiO 2 powders were synthesized by mechanical alloying (MA) with varying Fe contents from 0 up to 4.8 wt.% to shift the absorption threshold into the visible light region. The photocatalytic feasibility of the Fe-doped TiO 2 powder was evaluated by quantifying the visible light absorption capacity using ultraviolet and visible (UV-Vis) spectroscopy and photoluminescence spectroscopy. Effects of Fe additions on the crystal structures and the morphologies of the Fe-doped powders were also investigated as a function of the doping content using transmission electron microscopy-electron diffraction pattern (TEM-EDP), X-ray diffraction (XRD) and energy dispersive X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS). The UV-Vis study showed that the UV absorption for the Fe-doped powder moved to a longer wavelength (red shift) and the photoefficiency was enhanced. Based on the analysis of the photoluminescence spectra, the red shift was believed to be induced by localizing the dopant level near the valence band of TiO 2 . The UV-Vis absorption depended on the Fe concentration. TEM-EDP and XRD investigations showed that the Fe-doped powder had a rutile phase in which the added Fe atoms were dissolved. The rutile phase was composed of spherical particles and chestnut bur shaped particles, resulting in a larger surface area than the spherical P-25 powder

NanoCrystalline Cellulose isolated from oil palm empty fruit bunch and its potential in cadmium metal removal

Directory of Open Access Journals (Sweden)

Lim Yong Hui

2016-01-01

Full Text Available NanoCrystalline Cellulose (NCC was isolated via ultrasonic cavitation assisted acid hydrolysis method. Characterization was done using Dynamic Light Scattering (DLS together with Scanning Electron Microscope (SEM imaging to double prove the existence of NCC. DLS measures length of 236.6 nm with width of 34.40 nm, supported by SEM which showed NCC a rod-like shaped particle with large surface area and high porosity. It was then attempted for heavy metal cadmium ion (Cd2+ removal from aqueous solution. The pH implication to the rate of Cd2+ adsorption was investigated by varying the solution to pH 4, pH 7 and pH 10 over a duration of 120 minutes. The removal efficiency was analyzed using Atomic Absorption Spectroscopy (AAS resulting in pH 7 being the most favorable for Cd2+ removal.

Impedance spectroscopy studies of Silver Doped Cadmium Sulphide Nanocrystallites

Science.gov (United States)

Sivanand, R.; Chellammal, S.; Manivannan, S.

2018-02-01

Using co-precipitation method, cadmium sulphide (CdS) and silver doped cadmium sulphide (CdS;Ag) was prepared. By using energy-dispersive X-ray analysis (EDXA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyse the structural characterization of the prepared samples. The energy-dispersive X-ray analysis (EDXA) measurement is used to confirm, the presence of elements in prepared samples. There is no peaks of other impurity were detected. The average size of nanoparticles was calculated by scherrer formula. SEM photographs indicate that the nanopowders consist of well dispersed agglomerates of grains with a narrow size distribution, whereas the sizes of the individual particles are between 5 and 12 nm. The synthesized samples have been structurally analysed by X-ray diffraction method. The peaks in the XRD pattern are in good matches with the standard values of JCPDS file and other impurity peaks of crystalline phases were not detected. Scanning electron microscopy (SEM) measurement is used for the morphological studies. Electrical conductivity studies are analysed by Impedance spectroscopy measurement and also calculate the activation energies at low and high temperature for prepared samples.

Doped cadmium sulfide particles in polymer matrix: X-ray diffraction, optical reflectivity and photoconductivity study

Czech Academy of Sciences Publication Activity Database

Franc, Jiří; Nešpůrek, Stanislav; Makarova, Marina; Krtil, Petr

2008-01-01

Roč. 10, č. 3 (2008), s. 520-527 ISSN 1454-4164 R&D Projects: GA MPO FT-TA2/018 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40500505 Keywords : cadmium sulphide * doping * polymer binder * photoconductivity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.577, year: 2008

Optical, thermal and magnetic studies of pure and cobalt chloride doped L-alanine cadmium chloride

Energy Technology Data Exchange (ETDEWEB)

Benila, B.S., E-mail: benjane.benila@gmail.com [Department of Physics and Research Centre, Scott Christian College (Autonomous), Nagercoil 629 003 (India); Bright, K.C. [Department of Physics, St. John' s College, Anchal, Kollam 691 306 (India); Delphine, S. Mary [Department of Physics, Holy Cross College (Autonomous), Nagercoil 629 004 (India); Shabu, R. [Department of Physics and Research Centre, Scott Christian College (Autonomous), Nagercoil 629 003 (India)

2017-03-15

Single crystals of L-alanine cadmium chloride (LACC) and cobalt chloride (Co{sup 2+}) doped LACC have been grown by the slow evaporation solution growth technique. The grown crystals were subjected to various characterizations such as powder XRD, SXRD, FTIR, UV–vis, EDAX, TG/DTA, VSM, Dielectric and Second Harmonic Generation (SHG) measurements. The lattice parameters of the grown crystals were determined by single crystal X-ray analysis. EDAX analysis confirms the presence of Co{sup 2+} ion in the host material. The functional group and optical behavior of the crystals were identified from FTIR and UV-vis spectrum analysis. Electrical parameters such as dielectric constant, dielectric loss have been studied. The thermal stability of the compound was found out using TGA/DTA analysis. Second Harmonic Generation of the samples was confirmed by Kurtz-Perry powder technique. Magnetic properties of the crystals studied by VSM were also reported. The encouraging results show that the cobalt chloride doped LACC crystals have greater potential applications in optical devices. - Graphical abstract: Fig (a) and (b) shows the transparent, stable single crystals of pure and doped crystals were obtained using slow evaporation technique. The sizes of pure and doped crystals are 20×9×2 mm{sup 3} and 18×15×1 mm{sup 3} respectively. Fig (c) is the Hysteresis loop traced at room temperature for the pure and doped crystals explains the soft ferromagnetic nature of the doped crystal. The provision for changing the value of coercivity can be used for security, switching and sensing applications. - Highlights: • Defect free crystals of pure and Co{sup 2+} ion doped L-alanine cadmium chloride were grown. • The optical, dielectric and magnetic properties of pure crystals were enhanced by adding Co{sup 2+} ion. • High optical transmittance was obtained in the entire visible and IR region. • Addition of dopant to the pure crystal altered the coercivity. • Low dielectric

Mg Doping Effect on the Microstructural and Optical Properties of ZnO Nanocrystalline Films

Directory of Open Access Journals (Sweden)

San-Lin Young

2015-01-01

Full Text Available Transparent Zn1-xMgxO (x=0.01, 0.03, and 0.05 nanocrystalline films were prepared by sol-gel method followed by thermal annealing treatment of 700°C. Mg doping effect on the microstructural and optical properties of the Zn1-xMgxO films is investigated. From SEM images of all films, mean sizes of uniform spherical grains increase progressively. Pure wurtzite structure is obtained from the results of XRD. Grain sizes increase from 34.7 nm for x=0.01 and 37.9 nm for x=0.03 to 42.1 nm for x=0.05 deduced from the XRD patterns. The photoluminescence spectra of the films show a strong ultraviolet emission and a weak visible light emission peak. The enhancement of ultraviolet emission and reduction of visible emission are observed due to the increase of Mg doping concentration and the corresponding decrease of oxygen vacancy defects. Besides, the characteristics of the dark/photo currents with n-Zn1-xMgxO/n-Si heterojunction are studied for photodetector application.

Nanocrystalline hydroxyapatite doped with magnesium and zinc: Synthesis and characterization

Energy Technology Data Exchange (ETDEWEB)

Kalita, Samar J. [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States)]. E-mail: samar@mail.ucf.edu; Bhatt, Himesh A. [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States)

2007-05-16

During recent years, there have been efforts in developing nanocrystalline bioceramics, to enhance their mechanical and biological properties for use in tissue engineering applications. In this research, we made an attempt to synthesize nanocrystalline bioactive hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HAp) ceramic powder in the lower-end of nano-range (2-10 nm), using a simple low-temperature sol-gel technique and studied its densification behavior. We further studied the effects of metal ion dopants during synthesis on powder morphology, and the properties of the sintered structures. Calcium nitrate and triethyl phosphite were used as precursors for calcium and phosphorous, respectively, for sol-gel synthesis. Calculated quantities of magnesium oxide and zinc oxide were incorporated as dopants into amorphous dried powder, prior to calcination at 250-550 {sup o}C. The synthesized powders were analyzed for their phases using X-ray diffraction technique and characterized for powder morphology and particle size using transmission electron microscopy (TEM). TEM analysis showed that the average particle size of the synthesized powders were in the range of 2-10 nm. The synthesized nano-powders were uniaxially compacted and then sintered at 1250 {sup o}C and 1300 {sup o}C for 6 h, separately, in air. A maximum average sintered density of 3.29 g/cm{sup 3} was achieved in structures sintered at 1300 {sup o}C, developed from nano-powder doped with magnesium. Vickers hardness testing was performed to determine the hardness of the sintered structures. Uniaxial compression tests were performed to evaluate the mechanical properties. Bioactivity and biodegradation behavior of the sintered structures were assessed in simulated body fluid (SBF) and maintained in a dynamic state.

Dosimetric and kinetic parameters of lithium cadmium borate glasses doped with rare earth ions

Directory of Open Access Journals (Sweden)

J. Anjaiah

2014-10-01

Full Text Available Thermoluminescence (TL characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr3+, Nd3+, Sm3+ and Eu3+ Li2O–Cdo–B2O3 glasses have been studied in the temperature range 303–573 K; the pure glass has exhibited single TL peak at 466 K. When this glass is doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Eu3+ doped glasses. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that europium doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter.

Effect of annealing and impurity concentration on the TL characteristics of nanocrystalline Mn-doped CaF2

International Nuclear Information System (INIS)

Sahare, P.D.; Singh, Manveer; Kumar, Pratik

2015-01-01

Nanocrystalline samples of Mn-doped CaF 2 were synthesized by chemical coprecipitation method. The impurity concentration was varied in the range of 0.5–4.0 mol%. The structure of the synthesized material was confirmed using powder XRD analysis. TEM images of the nanoparticles show their size occurring mostly in the range of 35–40 nm, with clusters of some impurity phases formed on annealing of the material at higher temperatures. Detailed studies on TL showed that the structures of glow curves depend on Mn concentrations and annealing temperatures. Optimization of the concentration and annealing temperature showed that the sample (doped with 3.0 mol% and annealed at 673 K) has almost a single dosimetric glow peak appearing at around 492 K. EPR and PL spectra were further studied to understand the reasons for changes in the glow curve structures. All detailed studies on TL, PL and EPR showed that the changes in glow curve structures are caused not only by the stress connected with the difference in ionic radii of host Ca 2+ and the guest impurity Mn 3+ /Mn 2+ , but are also governed by other reasons, like diffusion of atmospheric oxygen and formation of impurity aggregates, such as, MnO 2 , Mn 3 O 4 , etc. This is true not only for nanocrystalline CaF 2 :Mn but could also be so for the bulk CaF 2 :Mn (TLD-400) and would thus help in understanding complex glow curve structure, high fading and the loss of reusability on annealing beyond 673 K. - Highlights: • Nanocrystalline material CaF 2 :Mn is prepared by simple coprecipitation method. • The material is studied by XRD, TEM, ESR, TL and PL techniques. • High impurity concentrations give rise to clusters causing material instability. • Changes in ESR and PL and glow curve structures are studied and explained. • Better characteristics than the bulk make the nanophosphor useful for dosimetry

Suppression of photo-leakage current in amorphous silicon thin-film transistors by n-doped nanocrystalline silicon

International Nuclear Information System (INIS)

Lin, Hung-Chien; Ho, King-Yuan; Hsu, Chih-Chieh; Yan, Jing-Yi; Ho, Jia-Chong

2011-01-01

The reduction of photo-leakage current of amorphous silicon thin-film transistors (a-Si TFTs) is investigated and is found to be successfully suppressed by the use of an n-doped nanocrystalline silicon layer (n+ nc-Si) as an ohmic contact layer. The shallow-level defects of n+ nc-Si can become trapping centres of photo-induced electrons as the a-Si TFT is operated under light illumination. A lower oxygen concentration during n+ nc-Si deposition can increase the creation of shallow-level defects and improve the contrast ratio of active matrix organic light-emitting diode panels.

Releasing cation diffusion in self-limited nanocrystalline defective ceria thin films

DEFF Research Database (Denmark)

Esposito, Vincenzo; Ni, D. W.; Gualandris, Fabrizio

2017-01-01

Acceptor-doped nanocrystalline cerium oxide thin films are mechanically constrained nano-domains, with film/substrate interfacial strain and chemical doping deadlock mass diffusion. In contrast, in this paper we show that chemical elements result in highly unstable thin films under chemical...

Monitoring of peptide induced disruption of artificial lipid membrane constructed on boron-doped nanocrystalline diamond by electrochemical impedance spectroscopy

Czech Academy of Sciences Publication Activity Database

Petrák, V.; Grieten, L.; Taylor, Andrew; Fendrych, František; Ledvina, Miroslav; Janssens, S. D.; Nesládek, M.; Haenen, K.; Wagner, P.

2011-01-01

Roč. 208, č. 9 (2011), s. 2099-2103 ISSN 1862-6300 R&D Projects : GA AV ČR KAN200100801; GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LD11076 Grant - others:European RD projects (XE) 238201-MATCON Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z10100520 Keywords : biosensor * boron-doped nanocrystalline diamond * electrochemical impedance spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.463, year: 2011

Synthesis, structural and property studies of Ni doped cadmium sulphide quantum dots stabilized in DETA matrix

International Nuclear Information System (INIS)

Mercy, A.; Jesper Anandhi, A.; Sakthi Murugesan, K.; Jayavel, R.; Kanagadurai, R.; Milton Boaz, B.

2014-01-01

Highlights: • Ni doped CdS nanoparticles are synthesized by chemical precipitation method. • X-ray diffractogram confirms the formation of CdS with dopant. • FTIR spectrum reveals that the nanosamples are encapsulated by DETA. • The UV-VIS absorption spectra shows strong blue shift. - Abstract: Pure and Nickel doped cadmium sulphide nanoparticles at pH value 10 with three different concentrations have been synthesized by chemical precipitation method. Diethylene triamine was used as stabilizing agent to control the particle size as quantum dots without any agglomeration. The synthesized samples were characterized with X-ray diffraction (XRD), High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Ultraviolet–Visible absorption spectroscopy (UV–VIS), Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) studies. The nano crystalline nature of the as prepared samples is confirmed using XRD analysis. The average size of Ni doped cadmium sulphide nanoparticles calculated from Debye Scherer formula was of the order of 1.5–3 nm and that of pure CdS nanoparticles was of the order of 6–7 nm. The same value of the particle size was confirmed by using Williamson Hall plot as well as Henglein’s formula. X-ray peak broadening analysis was carried out using Williamson–Hall plot. The surface morphology studies of the sample using HRSEM images show the formation of nanoclusters and the EDAX spectra confirms the presence of cadmium sulphide and nickel elements in the sample. TEM images establish the stabilization of CdS nanoparticles in DETA. The UV–VIS absorption spectra of the sample show blue shift in the absorption region due to the quantum confinement effect. FTIR studies have been carried out to establish the presence of bonding by capping agent in the Ni doped samples. The synthesized samples show photoluminescence in the spectral region from 350 to 550

Nanocrystalline Silicon Carrier Collectors for Silicon Heterojunction Solar Cells and Impact on Low-Temperature Device Characteristics

KAUST Repository

Nogay, Gizem

2016-09-26

Silicon heterojunction solar cells typically use stacks of hydrogenated intrinsic/doped amorphous silicon layers as carrier selective contacts. However, the use of these layers may cause parasitic optical absorption losses and moderate fill factor (FF) values due to a high contact resistivity. In this study, we show that the replacement of doped amorphous silicon with nanocrystalline silicon is beneficial for device performance. Optically, we observe an improved short-circuit current density when these layers are applied to the front side of the device. Electrically, we observe a lower contact resistivity, as well as higher FF. Importantly, our cell parameter analysis, performed in a temperature range from -100 to +80 °C, reveals that the use of hole-collecting p-type nanocrystalline layer suppresses the carrier transport barrier, maintaining FF s in the range of 70% at -100 °C, whereas it drops to 40% for standard amorphous doped layers. The same analysis also reveals a saturation onset of the open-circuit voltage at -100 °C using doped nanocrystalline layers, compared with saturation onset at -60 °C for doped amorphous layers. These findings hint at a reduced importance of the parasitic Schottky barrier at the interface between the transparent electrodes and the selective contact in the case of nanocrystalline layer implementation. © 2011-2012 IEEE.

Nanocrystalline Silicon Carrier Collectors for Silicon Heterojunction Solar Cells and Impact on Low-Temperature Device Characteristics

KAUST Repository

Nogay, Gizem; Seif, Johannes Peter; Riesen, Yannick; Tomasi, Andrea; Jeangros, Quentin; Wyrsch, Nicolas; Haug, Franz-Josef; De Wolf, Stefaan; Ballif, Christophe

2016-01-01

Silicon heterojunction solar cells typically use stacks of hydrogenated intrinsic/doped amorphous silicon layers as carrier selective contacts. However, the use of these layers may cause parasitic optical absorption losses and moderate fill factor (FF) values due to a high contact resistivity. In this study, we show that the replacement of doped amorphous silicon with nanocrystalline silicon is beneficial for device performance. Optically, we observe an improved short-circuit current density when these layers are applied to the front side of the device. Electrically, we observe a lower contact resistivity, as well as higher FF. Importantly, our cell parameter analysis, performed in a temperature range from -100 to +80 °C, reveals that the use of hole-collecting p-type nanocrystalline layer suppresses the carrier transport barrier, maintaining FF s in the range of 70% at -100 °C, whereas it drops to 40% for standard amorphous doped layers. The same analysis also reveals a saturation onset of the open-circuit voltage at -100 °C using doped nanocrystalline layers, compared with saturation onset at -60 °C for doped amorphous layers. These findings hint at a reduced importance of the parasitic Schottky barrier at the interface between the transparent electrodes and the selective contact in the case of nanocrystalline layer implementation. © 2011-2012 IEEE.

Effect of Gallium Doping on the Characteristic Properties of Polycrystalline Cadmium Telluride Thin Film

Science.gov (United States)

Ojo, A. A.; Dharmadasa, I. M.

2017-08-01

Ga-doped CdTe polycrystalline thin films were successfully electrodeposited on glass/fluorine doped tin oxide substrates from aqueous electrolytes containing cadmium nitrate (Cd(NO3)2·4H2O) and tellurium oxide (TeO2). The effects of different Ga-doping concentrations on the CdTe:Ga coupled with different post-growth treatments were studied by analysing the structural, optical, morphological and electronic properties of the deposited layers using x-ray diffraction (XRD), ultraviolet-visible spectrophotometry, scanning electron microscopy, photoelectrochemical cell measurement and direct-current conductivity test respectively. XRD results show diminishing (111)C CdTe peak above 20 ppm Ga-doping and the appearance of (301)M GaTe diffraction above 50 ppm Ga-doping indicating the formation of two phases; CdTe and GaTe. Although, reductions in the absorption edge slopes were observed above 20 ppm Ga-doping for the as-deposited CdTe:Ga layer, no obvious influence on the energy gap of CdTe films with Ga-doping were detected. Morphologically, reductions in grain size were observed at 50 ppm Ga-doping and above with high pinhole density within the layer. For the as-deposited CdTe:Ga layers, conduction type change from n- to p- were observed at 50 ppm, while the n-type conductivity were retained after post-growth treatment. Highest conductivity was observed at 20 ppm Ga-doping of CdTe. These results are systematically reported in this paper.

Fabrication of boron-doped nanocrystalline diamond nanoflowers based on 3D Cu(OH)2 dendritic architectures

International Nuclear Information System (INIS)

Sim, Huijun; Hong, Sukin; Lee, Seungkoo; Lim, Daesoon; Jin, Juneon; Hwang, Sungwoo

2012-01-01

Hot-filament chemical vapor deposition (HFCVD) was used to prepare boron-doped nanocrystalline diamond (BDND) nanoflowers on a Cu substrate with a Cu(OH) 2 dendritic architecture that had been formed by using electrostatic self-assembly (ESA) method with nanodiamond particles. The formation of diamond nanoflowers is controlled by the reaction time between the Cu(OH) 2 nanoflowers and the polymeric linker for the electrostatic attachment of nanodiamonds and by the deposition time for CVD diamond growth with a high nucleation density. Through analysis by field emission scanning electron microscopy (FESEM) and Raman spectroscopy, the optimal conditions for the synthesis of BDND nanoflowers are determined, and a possible explanation is provided.

Carbon doped ZnO: Synthesis, characterization and interpretation

International Nuclear Information System (INIS)

Mishra, D.K.; Mohapatra, J.; Sharma, M.K.; Chattarjee, R.; Singh, S.K.; Varma, Shikha; Behera, S.N.; Nayak, Sanjeev K.; Entel, P.

2013-01-01

A novel thermal plasma in-flight technique has been adopted to synthesize nanocrystalline ZnO and carbon doped nanocrystalline ZnO matrix. Transmission electron microscopy (TEM) studies on these samples show the average particle sizes to be around 32 nm for ZnO and for carbon doped ZnO. An enhancement of saturation magnetization in nanosized carbon doped ZnO matrix by a factor of 3.8 has been found in comparison to ZnO nanoparticles at room temperature. Raman measurement clearly indicates the presence of Zn–C complexes surrounded by ZnO matrix in carbon doped ZnO. This indicates that the ferromagnetic signature in carbon doped ZnO arises from the creation of defects or the development of oxy-carbon clusters, in the carbon doped ZnO system. Theoretical studies based on density functional theory also support the experimental analyses. - Highlights: ► Synthesis of nanocrystalline ZnO and carbon doped ZnO matrix by inflight thermal plasma reactor. ► Enhancement of ferromagnetism in nanosized carbon doped ZnO in comparison to ZnO nanoparticles. ► Raman measurement indicates the presence of Zn–C complexes surrounded by ZnO matrix. ► Ferromagnetic signature in carbon doped ZnO arises from the development of oxy-carbon clusters. ► DFT supports experimental evidence of ferromagnetism in C doped ZnO nanoparticles.

Effect of Aluminum Doping on the Nanocrystalline ZnS:Al3+ Films Fabricated on Heavily-Doped p-type Si(100) Substrates by Chemical Bath Deposition Method

Science.gov (United States)

Zhu, He-Jie; Liang, Yan; Gao, Xiao-Yong; Guo, Rui-Fang; Ji, Qiang-Min

2015-06-01

Intrinsic ZnS and aluminum-doped nanocrystalline ZnS (ZnS:Al3+) films with zinc-blende structure were fabricated on heavily-doped p-type Si(100) substrates by chemical bath deposition method. Influence of aluminum doping on the microstructure, and photoluminescent and electrical properties of the films, were intensively investigated. The average crystallite size of the films varying in the range of about 9.0 ˜ 35.0 nm initially increases and then decreases with aluminum doping contents, indicating that the crystallization of the films are initially enhanced and then weakened. The incorporation of Al3+ was confirmed from energy dispersive spectrometry and the induced microstrain in the films. Strong and stable visible emission band resulting from the defect-related light emission were observed for the intrinsic ZnS and ZnS:Al3+ films at room temperature. The photoluminescence related to the aluminum can annihilate due to the self-absorption of ZnS:Al3+ when the Al3+ content surpasses certain value. The variation of the resistivity of the films that initially reduces and then increases is mainly caused by the partial substitute for Zn2+ by Al3+ as well as the enhanced crystallization, and by the enhanced crystal boundary scattering, respectively.

Nanocrystalline hydroxyapatite doped with selenium oxyanions: A new material for potential biomedical applications

International Nuclear Information System (INIS)

Kolmas, Joanna; Oledzka, Ewa; Sobczak, Marcin; Nałęcz-Jawecki, Grzegorz

2014-01-01

Selenium-substituted hydroxyapatites containing selenate SeO 4 2− or selenite SeO 3 2− ions were synthesized using a wet precipitation method. The selenium content was determined by atomic absorbance spectrometry. The raw, unsintered powders were also characterized using powder X-ray diffraction, middle-range FT-IR spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopic microanalysis. The synthesized apatites were found to be pure and nanocrystalline with a crystal size similar to that in bone mineral. The incorporation of selenium oxyanions into the crystal lattice was confirmed. The toxicity of hydroxyapatites containing selenite or selenate ions was evaluated with a protozoan assay and bacterial luminescence test. - Highlights: • We synthesized and analyzed hydroxyapatites doped with selenium oxyanions. • We used various analytical methods, i.e. XRD, TEM, AAS and FT-IR. • We confirmed incorporation of SeO 3 2− and SeO 4 2− into the crystal lattice. • The toxicity of the materials was studied

Fabrication of boron-doped nanocrystalline diamond nanoflowers based on 3D Cu(OH){sub 2} dendritic architectures

Energy Technology Data Exchange (ETDEWEB)

Sim, Huijun; Hong, Sukin; Lee, Seungkoo; Lim, Daesoon; Jin, Juneon; Hwang, Sungwoo [Korea University, Seoul (Korea, Republic of)

2012-03-15

Hot-filament chemical vapor deposition (HFCVD) was used to prepare boron-doped nanocrystalline diamond (BDND) nanoflowers on a Cu substrate with a Cu(OH){sub 2} dendritic architecture that had been formed by using electrostatic self-assembly (ESA) method with nanodiamond particles. The formation of diamond nanoflowers is controlled by the reaction time between the Cu(OH){sub 2} nanoflowers and the polymeric linker for the electrostatic attachment of nanodiamonds and by the deposition time for CVD diamond growth with a high nucleation density. Through analysis by field emission scanning electron microscopy (FESEM) and Raman spectroscopy, the optimal conditions for the synthesis of BDND nanoflowers are determined, and a possible explanation is provided.

Anomalous behavior of B1g mode in highly transparent anatase nano-crystalline Nb-doped Titanium Dioxide (NTO thin films

Directory of Open Access Journals (Sweden)

Subodh K. Gautam

2015-12-01

Full Text Available The effect of Niobium doping and size of crystallites on highly transparent nano-crystalline Niobium doped Titanium Dioxide (NTO thin films with stable anatase phase are reported. The Nb doping concentration is varied within the solubility limit in TiO2 lattice. Films were annealed in controlled environment for improving the crystallinity and size of crystallites. Elemental and thickness analysis were carried out using Rutherford backscattering spectrometry and cross sectional field emission scanning electron microscopy. Structural characteristics reveal a substitutional incorporation of Nb+5 in the TiO2 lattice which inhibits the anatase crystallites growth with increasing the doping percentage. The micro-Raman (MR spectra of films with small size crystallites shows stiffening of about 4 cm−1 for the Eg(1 mode and is ascribed to phonon confinement and non-stoichiometry. In contrast, B1g mode exhibits a large anomalous softening of 20 cm−1 with asymmetrical broadening; which was not reported for the case of pure TiO2 crystallites. This anomalous behaviour is explained by contraction of the apical Ti-O bonds at the surface upon substitutional Nb5+ doping induced reduction of Ti4+ ions also known as hetero-coordination effect. The proposed hypotheses is manifested through studying the electronic structure and phonon dynamics by performing the near edge x-ray absorption fine structure (NEXAFS and temperature dependent MR down to liquid nitrogen temperature on pure and 2.5 at.% doped NTO films, respectively.

A study of the structure and crystallisation of nanocrystalline zirconia

International Nuclear Information System (INIS)

Tucker, M.

1999-12-01

Nanocrystalline zirconia, prepared via, calcination of the hydroxide, has been studied using a variety of experimental techniques. Two chemical routes, a precipitation and a sol-gel route, were used to prepare the hydroxide. Neutron and X-ray diffraction, EXAFS, NMR and SANS have been used to study the structure and crystallisation, during in-situ and ambient condition measurements. The structural information from the diffraction data has been complimented by the other techniques to provide information on the short, medium and longer range structure of nanocrystalline zirconia. Pure and yttrium doped samples were studied, this enabled the affects of doping and preparation routes to be investigated. The amorphous hydroxide was found to have a, monoclinic-like structure for all samples, independent of preparation route or yttrium content. The crystallisation temperature was lowest for the pure precipitation sample and was increased by the addition of yttrium or by preparation via, the sol-gel route. For the precipitation samples, in addition to the crystallisation temperature being raised, doping with yttrium also had an effect on the size of the crystallites obtained at high temperatures. Due to the different incorporation method of the yttrium into the sol-gel samples the effect on crystallite size and crystallisation temperature, as seen for the precipitation samples, were not evident for the sol-gel samples. The neutron and NMR data clearly show hydrogen remains in the samples well after crystallisation has become evident. The structural picture of nanocrystalline zirconia consisting of small crystallites surrounded by material containing, or terminated by, hydroxyl groups, is supported by all the results and methods used in this thesis. The in-situ and ambient conditions data is combined into a coherent growth picture of the nanocrystalline material from the hydroxide until at high enough temperatures the bulk or polycrystalline material is formed. (author)

Influence of rare earth (Nd{sup +3}) doping on structural and magnetic properties of nanocrystalline manganese-zinc ferrite

Energy Technology Data Exchange (ETDEWEB)

Naik, Pranav P., E-mail: drppn1987@gmail.com [Department of Physics, Goa University, Taleigao Plateau, Goa, 403206 (India); Tangsali, R.B. [Department of Physics, Goa University, Taleigao Plateau, Goa, 403206 (India); Meena, S.S.; Yusuf, S.M. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India)

2017-04-15

Ultrafine nanopowders of Mn{sub 0.6}Zn{sub 0.4}Fe{sub 2-x}Nd{sub x}O{sub 4} (x = 0, 0.04, 0.06, 0.08, and 0.1) were prepared using combustion method. The influence of Nd{sup +3} doping on structural parameters, morphological characteristics and magnetic properties were investigated. Formation of pure spinel phase was confirmed using X-ray powder diffraction (XRPD). Nd{sup +3} doping in Mn-Zn ferrite samples have shown remarkable influence on all the properties that were under investigation. An increase in lattice constant commensurate with increasing Nd{sup +3} concentrations was observed in the samples. The crystallite size calculated from XRPD data and grain size observed from Transmission Electron Microscope showed a proportionate decrement with increment in rare earth doping. An increase in mass density, X-ray density, particle strain and decrease in porosity were the other effects noticed on the samples as a result of Nd{sup +3} doping. The corresponding tetrahedral, octahedral bond lengths and bond angles estimated from XRPD data have also shown substantial influence of the Nd{sup +3} doping. Magnetic parameters namely saturation magnetization (M{sub S}) and net magnetic moment η{sub B}, estimated using vibrating sample magnetometer (VSM) were found to depend on the Nd{sup +3} doping. Mössbauer spectroscopy was employed to study the magnetic environment of Mössbauer active ions and detection of superparamagnetic behavior in nanocrystalline rare earth ferrite material. The isomer shift values obtained from Mössbauer spectra indicate the presence of Fe{sup +3} ions at tetrahedral site (A-site) and octahedral site (B-site), respectively. - Highlights: • Synthesis of Nd doped Mn-Zn ferrite nanoparticles using combustion method. • Successful doping of Nd{sup +3} at octahedral site in ferrite structure. • Existence of Fe{sup +3} oxidation state at both A-Site and B-site. • Enhanced saturation magnetization due to altered cation distribution by Nd doping

Enhanced photocatalytic activity of cadmium-doped Bi{sub 2}WO{sub 6} nanoparticles under simulated solar light

Energy Technology Data Exchange (ETDEWEB)

Song, Xu Chun, E-mail: songxuchunfj@163.com; Li, Wen Ting [Fujian Normal University, Department of Chemistry (China); Huang, Wan Zhen; Zhou, Huan [Zhejiang University of Technology, Research Center of Analysis and Measurement (China); Yin, Hao Yong [Hangzhou Dianzi University, Institute of Environmental Science and Engineering (China); Zheng, Yi Fan [Zhejiang University of Technology, Research Center of Analysis and Measurement (China)

2015-03-15

Novel cadmium-doped Bi{sub 2}WO{sub 6} nanoparticles with different Cd contents have been synthesized by a one-step route using ethylene glycol and water as solvents at 180 °C for 12 h. The as-synthesized samples were characterized in detailed by SEM, XRD, EDS, HRTEM, UV–Vis DRS, BET techniques, and so on. The results shown that with the increase of the Cd{sup 2+} addition, the crystal structure, lattice space, and absorption edge were not significantly changed and the calculated band gap value was 2.58 eV. However, the flower-like Bi{sub 2}WO{sub 6} sphere was gradually destroyed. Simultaneously, the surface area and photocurrent responses of the catalysts were greatly increased. Photocatalytic activity of the Cd-doped Bi{sub 2}WO{sub 6} samples was determined by monitoring the change of RhB concentration under simulated solar light. The results revealed that cadmium doping greatly improved the photocatalytic efficiency of Bi{sub 2}WO{sub 6}. The Bi{sub 2}WO{sub 6} sample with R{sub Cd} = 0.05 displayed the highest photocatalytic activity, and the degradation rate is about two times greater than pure Bi{sub 2}WO{sub 6}. Moreover, the Cd–Bi{sub 2}WO{sub 6} photocatalyst remained stable even after five consecutive cycles. A possible mechanism of photocatalytic activity enhancement on basis of the experimental results was proposed.

Nanocrystalline Mn-Mo-Ce Oxide Anode Doped Rare Earth Ce and Its Selective Electro-catalytic Performance

Directory of Open Access Journals (Sweden)

SHI Yan-hua

2017-09-01

Full Text Available The anode oxide of nanocrystalline Mn-Mo-Ce was prepared by anode electro-deposition technology, and its nanostructure and selective electro-catalytic performance were investigated using the SEM, EDS, XRD, HRTEM, electrochemical technology and oxygen evolution efficiency testing. Furthermore, the selective electro-catalytic mechanism of oxygen evolution and chlorine depression was discussed. The results show that the mesh-like nanostructure Mn-Mo-Ce oxide anode with little cerium doped is obtained, and the oxygen evolution efficiency for the anode in the seawater is 99.51%, which means a high efficiency for the selective electro-catalytic for the oxygen evolution. Due to the structural characteristics of γ-MnO2, the OH- ion is preferentially absorbed, while Cl- absorption is depressed. OH- accomplishes the oxygen evolution process during the valence transition electrocatalysis of Mn4+/Mn3+, completing the selective electro-catalysis process. Ce doping greatly increases the reaction activity, and promotes the absorption and discharge; the rising interplanar spacing between active (100 crystalline plane promotes OH- motion and the escape of newborn O2, so that the selective electro-catalytic property with high efficient oxygen evolution and chlorine depression is achieved from the nano morphology effect.

Electrical, optical and photoelectric properties of cadmium sulfide monocrystals doped by indium and irradiated by electrons

CERN Document Server

Davidyuk, G E; Manzhara, V S

2002-01-01

One studied effect of irradiation by E = 1.2 MeV energy and PHI = 2 x 10 sup 1 sup 7 cm sup - sup 2 dose fast electrons on electrical, optical and photoelectrical CdS single-crystals doped by In. On the basis of analysis of the experimental results one makes conclusions about decomposition and, in this case, indium atoms occurring in cation sublattice nodes are knocked out by cadmium atoms. In CdS:In irradiated specimens one detected new centres of slow recombination with occurrence of maximums of photoconductivity optical suppression within lambda sub M sub sub 1 = 0.75 mu m and lambda sub M sub sub 2 = 1.03 mu m range. It is assumed that complexes containing cadmium vacancies and indium atoms are responsible for recombination new centres

Visible active nanocrystalline N-doped anatase TiO{sub 2} particles for photocatalytic mineralization studies

Energy Technology Data Exchange (ETDEWEB)

Barkul, R.P. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Koli, V.B.; Shewale, V.B. [Department of Chemistry, Shivaji University, Kolhapur, 416 004, MS (India); Patil, M.K. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Delekar, S.D., E-mail: sddelekar7@rediffmail.com [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub–campus Osmanabad, 413 501, MS (India); Department of Chemistry, Shivaji University, Kolhapur, 416 004, MS (India); Department of Chemistry and Biochemistry, Florida State University, Tallahassee, 30306-4390, FL (United States)

2016-04-15

Nitrogen-doped TiO{sub 2} nanoparticles (N–TiO{sub 2} NPs) with anatase phase were synthesized by sol–gel method using a single precursor containing titanium (IV) terbutoxide, glacial acetic acid, sodium dodecyl sulphate, ammonia, and urea. X-ray diffraction (XRD) reveals the nanocrystalline nature with anatase phase of all the samples. The particle size of all samples was found in the range of 5–12 nm using transmission electron microscopy (TEM). UV–visible absorption measurements examined that the optical band gap of the doped samples decrease with increase in dopant concentration from 0.0 to 7.0 mol%. Field-emission scanning electron microscopy (FESEM) with energy dispersive atomic X-ray (EDAX) spectroscopy was employed to analyse the morphology and chemical composition of these N–TiO{sub 2} NPs. The photocatalytic activity of bare/doped TiO{sub 2} samples was demonstrated for the degradation of Rhodamine B (RhB) dye under direct sunlight irradiation. The photocatalytic degradation was monitored by measuring the kinetic parameters based on UV–visible spectroscopy as well as the chemical oxygen demand (COD) during the course of the reaction. The effect of dye concentration and pH of the solution on the photocatalytic degradation reaction in the presence of colloidal bare/doped TiO{sub 2} were also studied. The N–TiO{sub 2} catalyst, with a nitrogen concentration of 7.0 mol%, showed the highest activity for photocatalytic mineralization of dye at acidic or alkaline medium than neutral condition under solar light irradiation directly. - Highlights: • Nitrogen doped TiO{sub 2} nanoparticles where synthesized by using simple sol–gel method at room temperature. • N–TiO{sub 2} nanoparticles shows red shift. • Hydroxylation on the surface of TiO{sub 2} increase with increasing nitrogen concentration. • In presence of sunlight N–TiO{sub 2} shows enhancement in degradation of RhB dye.

Co+ -ion implantation induced doping of nanocrystalline CdS thin films: structural, optical, and vibrational properties

International Nuclear Information System (INIS)

Chandramohan, S.; Sarangi, S.N.; Majumder, S.; Som, T.; Kanjilal, A.; Sathyamoorthy, R.

2009-01-01

Full text: Transition metal (Mn, Fe, Co and Ni) doped CdS nanostructures and nanocrystalline thin films have attracted much attention due to their anticipated applications in magneto-optical, non-volatile memory and future spintronics devices. Introduction of impurities in substitutional positions is highly desirable for such applications. Ion implantation is known to provide many advantages over conventional methods for efficient doping and possibility of its seamless integration with device processing steps. It is not governed by equilibrium thermodynamics and offers the advantages of high spatial selectivity and to overcome the solubility limits. In this communication, we report on modifications of structural morphological, optical, and vibrational properties of 90 keV Co + -ion implanted CdS thin films grown by thermal evaporation. Co + -ion implantation was performed in the fluence range of 0.1-3.6x10 16 ions cm -2 These fluences correspond to Co concentration in the range of 0.34-10.8 at % at the peak position of profile. Implantation was done at an elevated temperature of 573 K in order to avoid amorphization and to enhance the solubility of Co ions in the CdS lattice. Films were characterized by glancing angle X-ray diffraction (GAXRD), atomic force microscopy (AFM), optical absorption, and micro-Raman spectroscopy. Implantation does not lead to any secondary phase formation either in the form of impurity or the metallic clusters. However, implantation improves the crystalline quality of the samples and leads to supersaturation of Co ions in the CdS lattice. Thus, nanocrystalline CdS thin films can be considered as a good radiation- resistant material, which can be employed for prolonged use in solar cells for space applications. The optical band gap is found to decrease systematically with increasing ion fluence from 2.39 to 2.28 eV. Implantation leads to agglomeration of grains and a systematic increase in the surface roughness. Both GAXRD and micro

Quantum transport in boron-doped nanocrystalline diamond

Czech Academy of Sciences Publication Activity Database

Mareš, Jiří J.; Hubík, Pavel; Krištofik, Jozef; Kindl, Dobroslav; Nesládek, Miloš

2008-01-01

Roč. 14, č. 7-8 (2008), s. 161-172 ISSN 0948-1907 R&D Projects: GA ČR GA202/07/0525; GA AV ČR IAA1010404; GA ČR(CZ) GA202/06/0040 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystalline diamond film * ballistic transport * superconductivity * Josephson’s effects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.483, year: 2008

Electrochromic devices based on wide band-gap nanocrystalline semiconductors functionalized with mononuclear charge transfer compounds

DEFF Research Database (Denmark)

Biancardo, M.; Argazzi, R.; Bignozzi, C.A.

2006-01-01

A series of ruthenium and iron mononuclear complexes were prepared and their spectroeletrochemical behavior characterized oil Optically Transparent Thin Layer Electrodes (OTTLE) and on Fluorine Doped SnO2 (FTO) conductive glasses coated with Sb-doped nanocrystalline SnO2. These systems display a ...

Oxygen reduction on nanocrystalline ruthenia-local structure effects

DEFF Research Database (Denmark)

Abbott, Daniel F.; Mukerjee, Sanjeev; Petrykin, Valery

2015-01-01

Nanocrystalline ruthenium dioxide and doped ruthenia of the composition Ru1-xMxO2 (M = Co, Ni, Zn) with 0 ≤ x ≤ 0.2 were prepared by the spray-freezing freeze-drying technique. The oxygen reduction activity and selectivity of the prepared materials were evaluated in alkaline media using the RRDE ...

Nanocrystalline hydroxyapatite doped with selenium oxyanions: A new material for potential biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Kolmas, Joanna, E-mail: joanna.kolmas@wum.edu.pl [Medical University of Warsaw, Faculty of Pharmacy, Department of Inorganic and Analytical Chemistry, ul. Banacha 1, 02-097 Warsaw (Poland); Oledzka, Ewa; Sobczak, Marcin [Medical University of Warsaw, Faculty of Pharmacy, Department of Inorganic and Analytical Chemistry, ul. Banacha 1, 02-097 Warsaw (Poland); Nałęcz-Jawecki, Grzegorz [Medical University of Warsaw, Faculty of Pharmacy, Department of Environmental Health Sciences, ul. Banacha 1, 02-097 Warsaw (Poland)

2014-06-01

Selenium-substituted hydroxyapatites containing selenate SeO{sub 4}{sup 2−} or selenite SeO{sub 3}{sup 2−} ions were synthesized using a wet precipitation method. The selenium content was determined by atomic absorbance spectrometry. The raw, unsintered powders were also characterized using powder X-ray diffraction, middle-range FT-IR spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopic microanalysis. The synthesized apatites were found to be pure and nanocrystalline with a crystal size similar to that in bone mineral. The incorporation of selenium oxyanions into the crystal lattice was confirmed. The toxicity of hydroxyapatites containing selenite or selenate ions was evaluated with a protozoan assay and bacterial luminescence test. - Highlights: • We synthesized and analyzed hydroxyapatites doped with selenium oxyanions. • We used various analytical methods, i.e. XRD, TEM, AAS and FT-IR. • We confirmed incorporation of SeO{sub 3}{sup 2−} and SeO{sub 4}{sup 2−} into the crystal lattice. • The toxicity of the materials was studied.

Structural Transformation upon Nitrogen Doping of Ultrananocrystalline Diamond Films by Microwave Plasma CVD

Directory of Open Access Journals (Sweden)

Chien-Chung Teng

2009-01-01

Full Text Available The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous and sp2/sp3 ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphous sp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films.

Fast response time alcohol gas sensor using nanocrystalline F

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 36; Issue 4. Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method. Sarbani Basu Yeong-Her Wang C Ghanshyam Pawan Kapur. Volume 36 Issue 4 August 2013 pp 521-533 ...

On the photo-luminescence properties of sol–gel derived undoped and Dy3+ ion doped nanocrystalline Scheelite type AMoO4 (A = Ca, Sr and Ba)

International Nuclear Information System (INIS)

Jena, Paramananda; Gupta, Santosh K.; Natarajan, V.; Padmaraj, O.; Satyanarayana, N.; Venkateswarlu, M.

2015-01-01

Nanocrystalline Scheelite type Dy doped AMoO 4 [where A = Ba, Sr and Ca] samples were prepared by acrylamide assisted sol–gel process and characterized by XRD, FT-Raman, FTIR, SEM and photoluminescence (PL). PL of undoped sample shows blue/green emission in CaMoO 4 and SrMoO 4 but multicolour visible emission leading to near white light in BaMoO 4 nanoparticles; the origin of which is explained. It was observed that on doping 0.5 mol% of Dy 3+ in molybdate samples complete energy transfer takes place in case of SrMoO 4 and BaMoO 4 , but host contributed substantially in Dy doped BaMoO 4 sample, resulting in biexponential decay. It was also observed that symmetry around Dy 3+ decreases as the size of alkaline earth ion increases. Due to combined blue, yellow and red colour emission in dysprosium doped sample; all samples showed near white light emission under UV and near UV excitation

Nanocrystalline spinel ferrites by solid state reaction route

Indian Academy of Sciences (India)

Wintec

Nanocrystalline spinel ferrites by solid state reaction route. T K KUNDU* and S MISHRA. Department of Physics, Visva-Bharati, Santiniketan 731 235, India. Abstract. Nanostructured NiFe2O4, MnFe2O4 and (NiZn)Fe2O4 were synthesized by aliovalent ion doping using conventional solid-state reaction route. With the ...

Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium

International Nuclear Information System (INIS)

Coccini, Teresa; Manzo, Luigi; Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura; Roda, Elisa

2011-01-01

Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with Cd (NP-Cd, 1 mg/animal) compared to soluble CdCl 2 (400 μg/animal), in Sprague Dawley rats treated intra-tracheally, 7 and 30 days after administration. NPs of silica containing Cd salt were prepared starting from commercial nano-size silica powder (HiSil T M T700 Degussa) with average pore size of 20 nm and surface area of 240 m 2 /g. Toxicogenomic analysis was performed by the DNA microarray technology (using Agilent Whole Rat Genome Microarray 4x44K) to evaluate changes in gene expression of the entire genome. These findings indicate that the whole genome analysis may represent a valuable approach to assess the whole spectrum of biological responses to cadmium containing nanomaterials.

Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium

Science.gov (United States)

Coccini, Teresa; Fabbri, Marco; Roda, Elisa; Grazia Sacco, Maria; Manzo, Luigi; Gribaldo, Laura

2011-07-01

Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with Cd (NP-Cd, 1 mg/animal) compared to soluble CdCl2 (400 μg/animal), in Sprague Dawley rats treated intra-tracheally, 7 and 30 days after administration. NPs of silica containing Cd salt were prepared starting from commercial nano-size silica powder (HiSil™ T700 Degussa) with average pore size of 20 nm and surface area of 240 m2/g. Toxicogenomic analysis was performed by the DNA microarray technology (using Agilent Whole Rat Genome Microarray 4×44K) to evaluate changes in gene expression of the entire genome. These findings indicate that the whole genome analysis may represent a valuable approach to assess the whole spectrum of biological responses to cadmium containing nanomaterials.

Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

Directory of Open Access Journals (Sweden)

Suvarna R. Bathe

2014-01-01

Full Text Available Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101 plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600 nm fiber diameter and nanocrystalline having size 40 nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3.

Effect of calcinations temperature on the luminescence intensity and fluorescent lifetime of Tb3+-doped hydroxyapatite (Tb-HA nanocrystallines

Directory of Open Access Journals (Sweden)

Hairong Yin

2017-06-01

Full Text Available Hydroxyapatite luminescent nanocrystallines doped with 6 mol.% Tb3+ (Tb-HA were prepared via chemical deposition method and calcined at different temperature, and the effects of calcinations temperature on the luminescence intensity and fluorescent lifetime were studied. TEM image of Tb-HA revealed that the shape of nanocrystallines changed from needle-like to short rod-like and sphere-like with the increase of calcinations temperature; while the particles sizes decreased from 190 nm to 110 nm. The crystallinity degree increased. The typical emission peaks attributed to Tb3+ ions were observed in emission spectra of 6 mol.% Tb-HA under 378 nm excitation. The luminescent intensity of Tb-HA, which showed the fluorescence quenching, firstly enhanced and then decreased at 700 °C; while the fluorescent lifetime increased firstly and then decreased after 600 °C. Furthermore, the ratio of intensity between 545 nm and 490 nm corresponding to electric-dipole and magnetic-dipole transition (IR: IO increases firstly and then decreases, which revealed that the proportion of substitute type and site of Ca2+ ions by Tb3+ ions were helpful to realize the substitute process and functional structure design.

Growth of boron doped hydrogenated nanocrystalline cubic silicon carbide (3C-SiC) films by Hot Wire-CVD

Energy Technology Data Exchange (ETDEWEB)

Pawbake, Amit [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Mayabadi, Azam; Waykar, Ravindra; Kulkarni, Rupali; Jadhavar, Ashok [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Waman, Vaishali [Modern College of Arts, Science and Commerce, Shivajinagar, Pune 411 005 (India); Parmar, Jayesh [Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 (India); Bhattacharyya, Somnath [Department of Metallurgical and Materials Engineering, IIT Madras, Chennai 600 036 (India); Ma, Yuan‐Ron [Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan (China); Devan, Rupesh; Pathan, Habib [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Jadkar, Sandesh, E-mail: sandesh@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-04-15

Highlights: • Boron doped nc-3C-SiC films prepared by HW-CVD using SiH{sub 4}/CH{sub 4}/B{sub 2}H{sub 6}. • 3C-Si-C films have preferred orientation in (1 1 1) direction. • Introduction of boron into SiC matrix retard the crystallanity in the film structure. • Film large number of SiC nanocrystallites embedded in the a-Si matrix. • Band gap values, E{sub Tauc} and E{sub 04} (E{sub 04} > E{sub Tauc}) decreases with increase in B{sub 2}H{sub 6} flow rate. - Abstract: Boron doped nanocrystalline cubic silicon carbide (3C-SiC) films have been prepared by HW-CVD using silane (SiH{sub 4})/methane (CH{sub 4})/diborane (B{sub 2}H{sub 6}) gas mixture. The influence of boron doping on structural, optical, morphological and electrical properties have been investigated. The formation of 3C-SiC films have been confirmed by low angle XRD, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy and high resolution-transmission electron microscopy (HR-TEM) analysis whereas effective boron doping in nc-3C-SiC have been confirmed by conductivity, charge carrier activation energy, and Hall measurements. Raman spectroscopy and HR-TEM analysis revealed that introduction of boron into the SiC matrix retards the crystallanity in the film structure. The field emission scanning electron microscopy (FE-SEM) and non contact atomic force microscopy (NC-AFM) results signify that 3C-SiC film contain well resolved, large number of silicon carbide (SiC) nanocrystallites embedded in the a-Si matrix having rms surface roughness ∼1.64 nm. Hydrogen content in doped films are found smaller than that of un-doped films. Optical band gap values, E{sub Tauc} and E{sub 04} decreases with increase in B{sub 2}H{sub 6} flow rate.

Enhanced magnetodielectric and multiferroic properties of Er-doped bismuth ferrite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, A.; Banerjee, M. [Department of Physics, National Institute of Technology, Durgapur 713209 (India); Basu, S., E-mail: soumen.basu@phy.nitdgp.ac.in [Department of Physics, National Institute of Technology, Durgapur 713209 (India); Mukadam, M.D.; Yusuf, S.M. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pal, M. [CSIR-Central Glass & Ceramic Research Institute, Kolkata 700032 (India)

2015-07-15

An enhancement in multiferroic properties has been achieved for chemically prepared BFO nanoparticles by doping with erbium (Er). XRD along with electron microscopy study reveals the phase purity and nanocrystalline nature of BFO. Enhancement of both the magnetic moment and resistivity is observed by virtue of Er doping. The observed enhanced magnetic moment is considered to be associated with smaller crystallite whereas increase of resistivity may be attributed to a decrease of oxygen vacancies. Doping also display an improvement of leakage behaviour and dielectric constant in nanocrystalline BFO, reflected in well-developed P-E loop. In addition, large enhancement in magnetodielectric coefficient is observed because of Er doping. Therefore, the results provide interesting approaches to improve the multiferroic properties of BFO, which has great implication towards its applications. - Highlights: • Synthesis of pure Er-doped BFO nanoparticles by chemical route. • Large increase in magnetic moment and resistivity due to Er doping. • Er doping produce well developed P-E loop and enhance polarization. • Drastic increase in dielectric constant as well as magnetodielectric coefficient observes because of Er doping.

Magnetic and Mössbauer studies of pure and Ti-doped YFeO _3 nanocrystalline particles prepared by mechanical milling and subsequent sintering

International Nuclear Information System (INIS)

Khalifa, N. O.; Widatallah, H. M.; Gismelseed, A. M.; Al-Mabsali, F. N.; Sofin, R. G. S.; Pekala, M.

2016-01-01

Single-phased nanocrystalline particles of pure and 10 % Ti "4"+-doped perovskite-related YFeO _3were prepared via mechanosynthesis at 450"∘C. This temperature is ∼150–350 "∘C lower than those at which the materials, in bulk form, are normally prepared. Rietveld refinements of the X-ray diffraction patterns reveal that the dopant Ti "4"+ ions prefer interstitial octahedral sites in the orthorhombic crystal lattice rather than those originally occupied by the expelled Fe "3"+ ions. Magnetic measurements show canted antiferromagnetism in both types of nanoparticles. Doping with Ti "4"+ lowers the Néel temperature of the YFeO _3 nanoparticles from ∼ 586 K to ∼ 521 K. The Ti "4"+-doped YFeO _3 nanoparticles exhibit enhanced magnetization and coercivity but less magnetic hyperfine fields relative to the un-doped nanoparticles. The "5"7Fe Mössbauer spectra show ∼ 15 % of the YFeO _3 nanoparticles and ∼22 of Ti "4"+-doped YFeO _3 ones to be superparamagnetic with blocking temperatures < 78 K. The broadened magnetic components in the "5"7Fe Mössbauer spectra suggest size-dependent hyperfine magnetic fields at the "5"7Fe nuclear sites and were associated with collective magnetic excitations. The "5"7Fe Mössbauer spectra show the local environments of the Fe "3"+ ions in the superparamagnetic nanoparticles to be more sensitive to the presence of the Ti "4"+ ions relative to those in the larger magnetic nanoparticles.

Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium

Energy Technology Data Exchange (ETDEWEB)

Coccini, Teresa; Manzo, Luigi [Toxicology Division, Salvatore Maugeri Foundation IRCCS, Pavia (Italy); Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura [European Commission, Joint Research Centre, IHCP- 21027 Ispra (Italy); Roda, Elisa [European Centre for Nanomedicine, University of Pavia, 27100 Pavia (Italy)

2011-07-06

Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with Cd (NP-Cd, 1 mg/animal) compared to soluble CdCl{sub 2} (400 {mu}g/animal), in Sprague Dawley rats treated intra-tracheally, 7 and 30 days after administration. NPs of silica containing Cd salt were prepared starting from commercial nano-size silica powder (HiSil{sup TM} T700 Degussa) with average pore size of 20 nm and surface area of 240 m{sup 2}/g. Toxicogenomic analysis was performed by the DNA microarray technology (using Agilent Whole Rat Genome Microarray 4x44K) to evaluate changes in gene expression of the entire genome. These findings indicate that the whole genome analysis may represent a valuable approach to assess the whole spectrum of biological responses to cadmium containing nanomaterials.

Photocatalytic characteristics for the nanocrystalline TiO{sub 2} on the Ag-doped CaAl{sub 2}O{sub 4}:(Eu,Nd) phosphor

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung-Sik, E-mail: jskim@uos.ac.kr; Sung, Hyun-Je; Kim, Bum-Joon

2015-04-15

Highlights: • The photocatalytic reactivity of the TiO{sub 2}-coated on the Ag-doped long-lasting phosphor (CaAl{sub 2}O{sub 4}:Eu{sup 2+},Nd{sup 3+}). • The photodecomposition of benzene gas under visible light irradiation. • The TiO{sub 2}-coated on the Ag-doped long-lasting phosphor showed much higher photocatalytic reactivity. • The light emitted from the long-lasting phosphors contributed to the photo generation of TiO{sub 2}. - Abstract: This study investigated the photocatalytic behavior of nanocrystalline TiO{sub 2} deposited on Ag-doped long-lasting phosphor (CaAl{sub 2}O{sub 4}:Eu{sup 2+},Nd{sup 3+}). The CaAl{sub 2}O{sub 4}:Eu{sup 2+},Nd{sup 3+} phosphor powders were prepared via conventional sintering using CaCO{sub 3}, Al{sub 2}O{sub 3}, Eu{sub 2}O{sub 3}, and Nd{sub 2}O{sub 3} as raw materials according to the appropriate molar ratios. Silver nanoparticles were loaded on the phosphor by mixing with an aqueous Ag-dispersion solution. Nanocrystalline TiO{sub 2} was deposited on Ag-doped CaAl{sub 2}O{sub 4}:Eu{sup 2+},Nd{sup 3+} powders via low-pressure chemical vapor deposition (LPCVD). The TiO{sub 2} coated on the phosphor was actively photo-reactive under irradiation with visible light and showed much faster benzene degradation than pure TiO{sub 2}, which is almost non-reactive. The coupling of TiO{sub 2} with phosphor may result in an energy band bending in the junction region, which then induces the TiO{sub 2} crystal at the interface to be photo-reactive under irradiation with visible light. In addition, the intermetallic compound of CaTiO{sub 3} that formed at the interface between TiO{sub 2} and the CaAl{sub 2}O{sub 4}:(Eu{sup 2+},Nd{sup 3+}) phosphor results in the formation of oxygen vacancies and additional electrons that promote the photodecomposition of benzene gas. The addition of Ag nanoparticles enhanced the photocatalytic reactivity of the TiO{sub 2}/CaAl{sub 2}O{sub 4}:Eu{sup 2+},Nd{sup 3+} phosphor. TiO{sub 2} on the Ag-doped

Electrodeposition of nanocrystalline CdSe thin films from dimethyl sulfoxide solution: Nucleation and growth mechanism, structural and optical studies

International Nuclear Information System (INIS)

Henriquez, R.; Badan, A.; Grez, P.; Munoz, E.; Vera, J.; Dalchiele, E.A.; Marotti, R.E.; Gomez, H.

2011-01-01

Highlights: → Electrodeposition of CdSe nanocrystalline semiconductor thin films. → Polycrystalline wurtzite structure with a slight (1010) preferred orientation. → Absorption edge shifts in the optical properties due to quantum confinement effects. - Abstract: Cadmium selenide (CdSe) nanocrystalline semiconductor thin films have been synthesized by electrodeposition at controlled potential based in the electrochemical reduction process of molecular selenium in dimethyl sulfoxide (DMSO) solution. The nucleation and growth mechanism of this process has been studied. The XRD pattern shows a characteristic polycrystalline hexagonal wurtzite structure with a slight (1 0 1 0) crystallographic preferred orientation. The crystallite size of nanocrystalline CdSe thin films can be simply controlled by the electrodeposition potential. A quantum size effect is deduced from the correlation between the band gap energy and the crystallite size.

Nanocrystalline SnO2:F Thin Films for Liquid Petroleum Gas Sensors

Directory of Open Access Journals (Sweden)

Sutichai Chaisitsak

2011-07-01

Full Text Available This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG sensors by doping with fluorine (F. Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer. The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO2 films was investigated. Atomic Force Microscopy (AFM and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO2 with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO2 was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection.

Host-Sensitized and Tunable Luminescence of GdNbO4:Ln3+ (Ln3+ = Eu3+/Tb3+/Tm3+) Nanocrystalline Phosphors with Abundant Color.

Science.gov (United States)

Liu, Xiaoming; Chen, Chen; Li, Shuailong; Dai, Yuhua; Guo, Huiqin; Tang, Xinghua; Xie, Yu; Yan, Liushui

2016-10-17

Up to now, GdNbO 4 has always been regarded as an essentially inert material in the visible region with excitation of UV light and electron beams. Nevertheless, here we demonstrate a new recreating blue emission of GdNbO 4 nanocrystalline phosphors with a quantum efficiency of 41.6% and host sensitized luminescence in GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors with abundant color in response to UV light and electron beams. The GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors were synthesized by a Pechini-type sol-gel process. With excitation of UV light and low-voltage electron beams, the obtained GdNbO 4 nanocrystalline phosphor presents a strong blue luminescence from 280 to 650 nm centered around 440 nm, and the GdNbO 4 :Ln 3+ nanocrystalline phosphors show both host emission and respective emission lines derived from the characterize f-f transitions of the doping Eu 3+ , Tb 3+ , and Tm 3+ ions. The luminescence color of GdNbO 4 :Ln 3+ nanocrystalline phosphors can be tuned from blue to green, red, blue-green, orange, pinkish, white, etc. by varying the doping species, concentration, and relative ratio of the codoping rare earth ions in GdNbO 4 host lattice. A single-phase white-light-emission has been realized in Eu 3+ /Tb 3+ /Tm 3+ triply doped GdNbO 4 nanocrystalline phosphors. The luminescence properties and mechanisms of GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) are updated.

Characterization of amorphous and nanocrystalline carbon films

International Nuclear Information System (INIS)

Chu, Paul K.; Li Liuhe

2006-01-01

Amorphous and nanocrystalline carbon films possess special chemical and physical properties such as high chemical inertness, diamond-like properties, and favorable tribological proprieties. The materials usually consist of graphite and diamond microstructures and thus possess properties that lie between the two. Amorphous and nanocrystalline carbon films can exist in different kinds of matrices and are usually doped with a large amount of hydrogen. Thus, carbon films can be classified as polymer-like, diamond-like, or graphite-like based on the main binding framework. In order to characterize the structure, either direct bonding characterization methods or the indirect bonding characterization methods are employed. Examples of techniques utilized to identify the chemical bonds and microstructure of amorphous and nanocrystalline carbon films include optical characterization methods such as Raman spectroscopy, Ultra-violet (UV) Raman spectroscopy, and infrared spectroscopy, electron spectroscopic and microscopic methods such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, transmission electron microscopy, and electron energy loss spectroscopy, surface morphology characterization techniques such as scanning probe microscopy (SPM) as well as other characterization methods such as X-ray reflectivity and nuclear magnetic resonance. In this review, the structures of various types of amorphous carbon films and common characterization techniques are described

Preparation of nanocrystalline Ni doped ZnS thin films by ammonia-free chemical bath deposition method and optical properties

Energy Technology Data Exchange (ETDEWEB)

Sahraei, Reza, E-mail: r.sahraei@ilam.ac.ir; Darafarin, Soraya

2014-05-01

Nanocrystalline Ni doped ZnS thin films were deposited on quartz, silicon, and glass substrates using chemical bath deposition method in a weak acidic solution containing ethylenediamine tetra acetic acid disodium salt (Na{sub 2}EDTA) as a complexing agent for zinc ions and thioacetamide (TAA) as a sulfide source at 80 °C. The films were characterized by energy-dispersive X-ray spectrometer (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectrophotometry, and photoluminescence (PL) spectroscopy. UV–vis transmission data showed that the films were transparent in the visible region. The X-ray diffraction analysis showed a cubic zinc blend structure. FE-SEM revealed a homogeneous morphology and dense nanostructures. The PL spectra of the ZnS:Ni films showed two characteristic bands, one broad band centered at 430 and another narrow band at 523 nm. Furthermore, concentration quenching effect on the photoluminescence intensity has been observed. - Highlights: • Nanocrystalline ZnS:Ni thin films were prepared by the chemical bath deposition method. • The size of ZnS:Ni nanocrystals was less than 10 nm showing quantum size effect. • SEM images demonstrated a dense and uniform surface that was free of pinholes. • The deposited films were highly transparent (>70%) in the visible region. • The PL spectra of ZnS:Ni thin films showed two emission peaks at 430 and 523 nm.

Magnetic and Mössbauer studies of pure and Ti-doped YFeO {sub 3} nanocrystalline particles prepared by mechanical milling and subsequent sintering

Energy Technology Data Exchange (ETDEWEB)

Khalifa, N. O. [University of Khartoum, Physics Department, Faculty of Science (Sudan); Widatallah, H. M., E-mail: hishammw@squ.edu.om; Gismelseed, A. M.; Al-Mabsali, F. N.; Sofin, R. G. S. [Sultan Qaboos University, Physics Department, College of Science (Oman); Pekala, M. [University of Warsaw, Chemistry Department (Poland)

2016-12-15

Single-phased nanocrystalline particles of pure and 10 % Ti {sup 4+}-doped perovskite-related YFeO {sub 3}were prepared via mechanosynthesis at 450{sup ∘}C. This temperature is ∼150–350 {sup ∘}C lower than those at which the materials, in bulk form, are normally prepared. Rietveld refinements of the X-ray diffraction patterns reveal that the dopant Ti {sup 4+} ions prefer interstitial octahedral sites in the orthorhombic crystal lattice rather than those originally occupied by the expelled Fe {sup 3+} ions. Magnetic measurements show canted antiferromagnetism in both types of nanoparticles. Doping with Ti {sup 4+} lowers the Néel temperature of the YFeO {sub 3} nanoparticles from ∼ 586 K to ∼ 521 K. The Ti {sup 4+}-doped YFeO {sub 3} nanoparticles exhibit enhanced magnetization and coercivity but less magnetic hyperfine fields relative to the un-doped nanoparticles. The {sup 57}Fe Mössbauer spectra show ∼ 15 % of the YFeO {sub 3} nanoparticles and ∼22 of Ti {sup 4+}-doped YFeO {sub 3} ones to be superparamagnetic with blocking temperatures < 78 K. The broadened magnetic components in the {sup 57}Fe Mössbauer spectra suggest size-dependent hyperfine magnetic fields at the {sup 57}Fe nuclear sites and were associated with collective magnetic excitations. The {sup 57}Fe Mössbauer spectra show the local environments of the Fe {sup 3+} ions in the superparamagnetic nanoparticles to be more sensitive to the presence of the Ti {sup 4+} ions relative to those in the larger magnetic nanoparticles.

Synthesis and antimicrobial activity of silver-doped hydroxyapatite nanoparticles.

Science.gov (United States)

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

2013-01-01

The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca(10-x)Ag(x)(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against gram-positive and gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures.

Viscoelastic optical nonlocality of doped cadmium oxide epsilon-near-zero thin films

Energy Technology Data Exchange (ETDEWEB)

Luk, Ting S.; De Ceglia, Domenico; Scalora, Michael; Vincenti, Maria A.; Campione, Salvatore; Kelley, Kyle; Maria, Jon-Paul; Keeler, Gordon A.

2017-08-01

Optical nonlocalities are elusive and hardly observable in traditional plasmonic materials like noble and alkali metals. Here we experimentally observe and theoretically model viscoelastic nonlocalities in the infrared optical response of a doped, cadmium oxide epsilon-near-zero thin film. The nonlocality is clearly detectable thanks to the low damping rate of conduction electrons and the virtual absence of interband transitions at infrared wavelengths. We describe the motion of conduction electrons using a hydrodynamic model for a viscoelastic fluid, and find excellent agreement with experimental results. The electrons’ elasticity blue-shifts the infrared plasmonic resonance associated with the main epsilon-near-zero mode, and triggers the onset of higher-order resonances due to the excitation of electron-pressure modes above the bulk plasma frequency. We also provide evidence of the existence of nonlocal damping, i.e., viscosity, in the motion of optically-excited conduction electrons using a combination of spectroscopic ellipsometry data and predictions based on the viscoelastic hydrodynamic model.

Optical and spectroscopic properties of neodymium doped cadmium-sodium borate glasses

Science.gov (United States)

Mohan, Shaweta; Thind, Kulwant Singh

2017-10-01

Neodymium doped cadmium sodium borate glasses having composition xCdO-(40-x) Na2CO3-59.5H3BO3-0.5Nd2O3; x = 10, 20 and 30 mol% were prepared by conventional melt-quenching technique. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. Conventional methods were used to determine the physical properties such as density, molar volume, refractive index, and rare earth ion concentration. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The calculated intensity parameters were further used to predict the radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the various fluorescent levels of Nd3+ ion in the prepared glass series. The effect of the compositional changes on the spectroscopic characteristics of Nd3+ ions have been studied and reported. The value of Ω2 is found to decrease with the decrease in the sodium content and the corresponding increase in the cadmium content. This can be ascribed to the changes in the asymmetry of the ligand field at the rare earth ion site and the change in rare earth oxygen (RE-O) covalency. Florescence spectra has been used to determine the peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σp) for the 4F3/2 → 4I9/2,4I11/2,4I13/2 transitions of the Nd3+ ion. The reasonably higher values of branching ratios and stimulated emission cross-section for the prepared glasses points towards the efficacy of these glasses as laser host materials. However, the glass with more sodium content is found to show better lasing properties.

Magnetic and frequency properties for nanocrystalline Fe-Ni alloys prepared by high-energy milling method

International Nuclear Information System (INIS)

Liu Yongsheng; Zhang Jincang; Yu, Liming; Jia Guangqiang; Jing Chao; Cao Shixun

2005-01-01

Fe-based nano-crystalline soft magnetic alloy with Ni-doping was fabricated successfully by high-energy milling. It was proved that a Fe-Ni solid solution is formed and the evaluated average grain size is about 20 nm. The effect of doping Ni on the frequency properties was systematically investigated. From the magnetic measurement results, it can be concluded that, the nickel doped decreases the resonance frequency of Fe-Ni alloy, but Ni doping enhances the frequency stability. The corresponding value of initial permeability as a function of Ni doping concentration was given at 10 kHz and the result indicates that the peak value of initial permeability shifts to the region of low Ni concentration for the samples milled for 72 h

Strategies for doped nanocrystalline silicon integration in silicon heterojunction solar cells

Czech Academy of Sciences Publication Activity Database

Seif, J.; Descoeudres, A.; Nogay, G.; Hänni, S.; de Nicolas, S.M.; Holm, N.; Geissbühler, J.; Hessler-Wyser, A.; Duchamp, M.; Dunin-Borkowski, R.E.; Ledinský, Martin; De Wolf, S.; Ballif, C.

2016-01-01

Roč. 6, č. 5 (2016), s. 1132-1140 ISSN 2156-3381 R&D Projects: GA MŠk LM2015087 Institutional support: RVO:68378271 Keywords : microcrystalline silicon * nanocrystalline silicon * silicon heterojunctions (SHJs) * solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.712, year: 2016

Substitutional Boron in Nanodiamond, Bucky-Diamond, and Nanocrystalline Diamond Grain Boundaries

Energy Technology Data Exchange (ETDEWEB)

Barnard, Amanda S.; Sternberg, Michael G.

2006-10-05

Although boron has been known for many years to be a successful dopant in bulk diamond, efficient doping of nanocrystalline diamond with boron is still being developed. In general, the location, configuration, and bonding structure of boron in nanodiamond is still unknown, including the fundamental question of whether it is located within grains or grain boundaries of thin films and whether it is within the core or at the surface of nanoparticles. Presented here are density functional tight-binding simulations examining the configuration, potential energy surface, and electronic charge of substitutional boron in various types of nanocrystalline diamond. The results predict that boron is likely to be positioned at the surface of isolated particles and at the grain boundary of thin-film samples.

Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles

Directory of Open Access Journals (Sweden)

Carmen Steluta Ciobanu

2013-01-01

Full Text Available The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca10−xAgx(PO46(OH2 nanoparticles (Ag:HAp-NPs for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures.

Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles

Science.gov (United States)

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

2013-01-01

The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca10−xAgx(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures. PMID:23509801

N-type doped nano-diamond in a first MEMS application

Energy Technology Data Exchange (ETDEWEB)

Dipalo, M.; Kusterer, J.; Janischowsky, K.; Kohn, E. [Dept. of Electron Devices and Circuits, University of Ulm, Albert Einstein Allee 45, 89081 Ulm (Germany)

2006-09-15

Nanocrystalline diamond is an interesting material for MEMS applications especially due to its outstanding mechanical, electrical and electrochemical properties. The current choice for doping is boron, resulting in p-type conduction. It has two difficulties: firstly, at high concentration (as needed for full activation) the lattice becomes highly stressed and may degrade the material's quality. Secondly, it contaminates the growth chamber, resulting in a memory effect. A recent alternative is n-type nitrogen doping, avoiding these disadvantages. However, nitrogen is mainly incorporated in the grain boundaries and thus inhomogeneously distributed. In turn this may limit the material's stability. Here we present a first trial to use nitrogen-doped nanocrystalline diamond (NCD), grown by hot filament CVD, in a water microjet as heater element. No stability problems were encountered even at high overdrive power. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Highly sensitive detection of urinary cadmium to assess personal exposure

Energy Technology Data Exchange (ETDEWEB)

Argun, Avni A.; Banks, Ashley M.; Merlen, Gwendolynne; Tempelman, Linda A. [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States); Becker, Michael F.; Schuelke, Thomas [Fraunhofer USA – CCL, 1449 Engineering Research Ct., East Lansing 48824, MI (United States); Dweik, Badawi M., E-mail: bdweik@ginerinc.com [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States)

2013-04-22

Highlights: ► An electrochemical sensor capable of detecting cadmium at parts-per-billion levels in urine. ► A novel fabrication method for Boron-Doped Diamond (BDD) ultramicroelectrode (UME) arrays. ► Unique combination of BDD UME arrays and a differential pulse voltammetry algorithm. ► High sensitivity, high reproducibility, and very low noise levels. ► Opportunity for portable operation to assess on-site personal exposure. -- Abstract: A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb{sup −1} cm{sup −2}) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.

Solid-state reaction kinetics and optical studies of cadmium doped magnesium hydrogen phosphate crystals

Science.gov (United States)

Verma, Madhu; Gupta, Rashmi; Singh, Harjinder; Bamzai, K. K.

2018-04-01

The growth of cadmium doped magnesium hydrogen phosphate was successfully carried out by using room temperature solution technique i.e., gel encapsulation technique. Grown crystals were confirmed by single crystal X-ray diffraction (XRD). The structure of the grown crystal belongs to orthorhombic crystal system and crystallizes in centrosymmetric space group. Kinetics of the decomposition of the grown crystals were studied by non-isothermal analysis. Thermo gravimetric / differential thermo analytical (TG/DTA) studies revealed that the grown crystal is stable upto 119 °C. The various steps involved in the thermal decomposition of the material have been analysed using Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova equations for evaluating various kinetic parameters. The optical studies shows that the grown crystals possess wide transmittance in the visible region and significant optical band gap of 5.5ev with cut off wavelength of 260 nm.

Doped titanium dioxide nanocrystalline powders with high photocatalytic activity

International Nuclear Information System (INIS)

Castro, A.L.; Nunes, M.R.; Carvalho, M.D.; Ferreira, L.P.; Jumas, J.-C.; Costa, F.M.; Florencio, M.H.

2009-01-01

Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with anatase structure were successfully synthesized through an hydrothermal route preceded by a precipitation doping step. Structural and morphological characterizations were performed by powder XRD and TEM. Thermodynamic stability studies allowed to conclude that the anatase structure is highly stable for all doped TiO 2 prepared compounds. The photocatalytic efficiency of the synthesized nanopowders was tested and the results showed an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 , whereas no photocatalytic activity was detected for the Fe:TiO 2 and Co:TiO 2 nanopowders. These results were correlated to the doping ions oxidation states, determined by Moessbauer spectroscopy and magnetization data. - Graphical abstract: Doped titanium dioxide nanopowders (M:TiO 2 ; M=Fe, Co, Nb, Sb) with highly stable anatase structure were successfully synthesized through an hydrothermal route. The photocatalytic efficiencies of the synthesized nanopowders were tested and the results show an appreciable enhancement in the photoactivity of the Sb:TiO 2 and Nb:TiO 2 .

Biominerals doped nanocrystalline nickel oxide as efficient humidity sensor: A green approach

International Nuclear Information System (INIS)

John Kennedy, L.; Magesan, P.; Judith Vijaya, J.; Umapathy, M.J.; Aruldoss, Udaya

2014-01-01

Graphical abstract: - Highlights: • A new resistive type of sensor was prepared by green synthesis. • The mineral oxide from seed part of Hygrophila spinosa T. Anders (HST) plant is chosen as a dopant in NiO. • The HST plant is found abundantly and commercially available in many countries. • The band gap of NH2 (Ni:HST of 0.5:0.5 weight ratio) sample is greater than prepared bulk NiO due to quantum effects. • The NH2 sample shows remarkable changes in the humidity sensing properties. - Abstract: The simple and green method is adopted for the preparation of biominerals (derived from the Hygrophila spinosa T. Anders plant seeds) doped nanocrystalline NiO. The prepared samples were subjected to instrumental analysis such as XRD, FT-IR, HR-SEM, EDX, UV–vis–DRS techniques. The surface area of all the samples was calculated from the Williamson–Hall's plot. The humidity sensitivity factor (S f ) of the prepared samples was evaluated by two probe dc electrical resistance method at different relative humidity levels. The change in the resistance was observed for the entire sensor samples except pure NiO (NH0). Compared to all the other composition, HST of 0.5% in NiO (NH2 sample) enhances the sensitivity factor (S f ) of about 90,000. The NH2 sample exhibited good linearity, reproducibility and response and recovery time about 210 ± 5 s and 232 ± 4 s, respectively. It is found that the sensitivity largely depends on composition, crystallite size and surface area

Thermoluminescence and optically stimulated luminescence properties of nanocrystalline Er3+ and Yb3+ doped Y3Al5O12 exposed to β-rays

International Nuclear Information System (INIS)

RodrIguez, R A; Rosa, E de la; Salas, P; Melendrez, R; Barboza-Flores, M

2005-01-01

The thermoluminescence (TL) and optically stimulated luminescence (OSL) characterization of Er 3+ and Yb 3+ doped Y 3 Al 5 O 12 nanocrystalline samples prepared by the precipitation process and exposed to β-rays are discussed. The TL as well as the OSL were two orders of magnitude higher in Er 3+ doped than in Yb 3+ specimens. The charge trapping and the radiative thermally stimulated recombination processes in Y 3 Al 5 O 12 : Er 3+ involve four trapping states at 166, 243, 342 and 424 deg. C, but just two trapping levels at 219 and 413 deg. C for Y 3 Al 5 O 12 : Yb 3+ at a heating rate of 10 deg. C s -1 . The photostimulation with 470 nm light causes in both phosphors a radiative recombination of the optically free charge carriers belonging to the same trapping states. The TL and the OSL as a function of radiation dose behaviour were linear in the 10-100 Gy dose range. The results provide evidence of the potential uses of these materials in radiation storage and dosimeter devices

Combustion synthesis of cadmium sulphide nanomaterials

Indian Academy of Sciences (India)

Anion-doped cadmium sulphide nanomaterials have been synthesized by using combustionmethod at normal atmospheric conditions. Oxidant/fuel ratios have been optimized in order to obtain CdS with best characteristics. Formation of CdS and size of crystallite were identified by X-ray diffraction and confirmed by ...

A novel single-step synthesis of N-doped TiO2 via a sonochemical method

International Nuclear Information System (INIS)

Wang, Xi-Kui; Wang, Chen; Guo, Wei-Lin; Wang, Jin-Gang

2011-01-01

Graphical abstract: The N-doped anatase TiO 2 nanoparticles were synthesized by sonochemical method. The as-prepared sample is characterized by XRD, TEM, XPS and UV-Vis DRS. The photocatalytic activity of the photocatalyst was evaluated by the photodegradation of an azo dye direct sky blue 5B. Highlights: → A novel singal-step sonochemical synthesis method for the preparation of anatase N-doped TiO 2 nanocrystalline at low temperature has been devoleped. → The as-prepared sample is characterized by XRD, TEM, XPS and UV-Vis DRS. → The photodegradation of azo dye direct sky blue 5 showed that the N-doped TiO 2 catalyst is of high visible-light photocatalytic activity. -- Abstract: A novel single-step synthetic method for the preparation of anatase N-doped TiO 2 nanocrystalline at low temperature has been devoleped. The N-doped anatase TiO 2 nanoparticles were synthesized by sonication of the solution of tetraisopropyl titanium and urea in water and isopropyl alcohol at 80 o C for 150 min. The as-prepared sample was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis absorption spectrum. The product structure depends on the reaction temperature and reaction time. The photocatalytic activity of the as-prepared photocatalyst was evaluated via the photodegradation of an azo dye direct sky blue 5B. The results show that the N-doped TiO 2 nanocrystalline prepared via sonication exhibit an excellent photocatalytic activity under UV light and simulated sunlight.

Synthesis and characterization of electrochemically deposited nanocrystalline CdTe thin films

Energy Technology Data Exchange (ETDEWEB)

Singh, Ragini Raj, E-mail: raginirajsingh@gmail.com [Department of Physics, Bhopal University, Bhopal-462026 (India); Department of Physical Electronics, Iby and Aladar Fleishman Faculty of Engineering, Tel-Aviv University, Tel-Aviv-69978 (Israel); Painuly, Diksha [Centre for Nanoscience and Nanotechnology, University of Kerala, Thiruanantpuram, Kerala (India); Pandey, R.K. [Department of Physics, Bhopal University, Bhopal-462026 (India)

2009-07-15

Electrodeposition is emerging as a method for the synthesis of semiconductor thin films and nanostructures. In this work we prepared the nanocrystalline CdTe thin films on indium tin oxide coated glass substrate from aqueous acidic bath at the deposition temperature 50 {+-} 1 deg. C. The films were grown potentiostatically from -0.60 V to -0.82 V with respect to saturated calomel reference electrode. The structural, compositional, morphological and optical properties were investigated using X-ray diffraction (XRD), energy dispersive analysis by X-rays (EDAX), atomic force microscopy (AFM), and UV-vis spectroscopy respectively and cyclic voltammetery. The structural and optical studies revealed that films are nanocrystalline in nature and possess cubic phase, also the films are preferentially oriented along the cubic (1 1 1) plane. The effect of cadmium composition on the deposited morphology was also investigated. The size dependent blue shift in the experimentally determined absorption edge has been compared with the theoretical predictions based on the effective mass approximation and tight binding approximation. It is shown that the experimentally determined absorption edges depart from the theoretically calculated values.

Influence of nitrogen dopants on N-doped TiO2 electrodes and their applications in dye-sensitized solar cells

International Nuclear Information System (INIS)

Guo Wei; Shen Yihua; Boschloo, Gerrit; Hagfeldt, Anders; Ma Tingli

2011-01-01

Highlights: → Three different types of nanocrystalline N-doped TiO 2 synthesized by several nitrogen dopants. → N-doped DSCs achieves a high conversion efficiency of 8.32%. → Ammonia acts as good nitrogen dopants. → Enhanced photocurrent of ca. 36% in N-doped DSCs. → Less charge are needed to get a high open-circuit voltage in N-doped films. - Abstract: Three different types of nanocrystalline, N-doped TiO 2 electrodes were synthesized using several nitrogen dopants through wet methods. The obtained nanocrystalline, N-doped TiO 2 electrodes possessed different crystallite sizes, surface areas, and N-doping amounts. Characterizations were performed to reveal the nitrogen-doping processes for the wet methods using ammonia, urea, and triethylamine as the nitrogen dopants. Additionally, a high conversion efficiency of 8.32% was achieved by the dye-sensitized solar cells, based on the N-doped TiO 2 electrodes. For instance, in comparison with the commercial P25 (5.76%) and pure anatase TiO 2 electrodes (7.14%), significant improvements (44% and 17%, respectively) in the efficiencies were obtained. The findings also indicated that the ammonia nitrogen dopant was more efficient than other two nitrogen dopants. The electron transports, electron lifetimes, and charge recombination in the dye-sensitized N-doped TiO 2 solar cells also differed from those in the pure TiO 2 -based dye-sensitized solar cells (DSCs). Specifically, an enhanced photocurrent of ca. 36% in N-doped DSCs resulted from the synergistic effects of the high dye uptake and the efficient electron transport. Moreover, the relationship between charge and voltage revealed that less charge was needed to get a high open-circuit voltage in the N-doping films.

Highly conducting p-type nanocrystalline silicon thin films preparation without additional hydrogen dilution

Science.gov (United States)

Patra, Chandralina; Das, Debajyoti

2018-04-01

Boron doped nanocrystalline silicon thin film has been successfully prepared at a low substrate temperature (250 °C) in planar inductively coupled RF (13.56 MHz) plasma CVD, without any additional hydrogen dilution. The effect of B2H6 flow rate on structural and electrical properties of the films has been studied. The p-type nc-Si:H films prepared at 5 ≤ B2H6 (sccm) ≤ 20 retains considerable amount of nanocrystallites (˜80 %) with high conductivity ˜101 S cm-1 and dominant crystallographic orientation which has been correlated with the associated increased ultra- nanocrystalline component in the network. Such properties together make the material significantly effective for utilization as p-type emitter layer in heterojunction nc-Si solar cells.

Characterization of nanocrystalline ZnO:Al films by sol-gel spin coating method

Energy Technology Data Exchange (ETDEWEB)

Gareso, P. L., E-mail: pgareso@gmail.com; Rauf, N., E-mail: pgareso@gmail.com; Juarlin, E., E-mail: pgareso@gmail.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Makassar 90245 (Indonesia); Sugianto,; Maddu, A. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bogor Institute of Culture, IPB Bogor (Indonesia)

2014-09-25

Nanocrystalline ZnO films doped with aluminium by sol-gel spin coating method have been investigated using optical transmittance UV-Vis and X-ray diffraction (X-RD) measurements. ZnO films were prepared using zinc acetate dehydrate (Zn(CH{sub 3}COO){sub 2}@@‡2H{sub 2}O), ethanol, and diethanolamine (DEA) as a starting material, solvent, and stabilizer, respectively. For doped films, AlCl{sub 3} was added to the mixture. The ZnO:Al films were deposited on a transparent conductive oxide (TCO) substrate using spin coating technique at room temperature with a rate of 3000 rpm in 30 sec. The deposited films were annealed at various temperatures from 400°C to 600°C during 60 minutes. The transmittance UV-Vis measurement results showed that after annealing at 400°C, the energy band gap profile of nanocrystalline ZnO:Al film was a blue shift. This indicated that the band gap of ZnO:Al increased after annealing due to the increase of crystalline size. As the annealing temperature increased the bandgap energy was a constant. In addition to this, there was a small oscillation occurring after annealing compared to the as–grown samples. In the case of X-RD measurements, the crystalinity of the films were amorphous before annealing, and after annealing the crystalinity became enhance. Also, X-RD results showed that structure of nanocrystalline ZnO:Al films were hexagonal polycrystalline with lattice parameters are a = 3.290 Å and c = 5.2531 Å.

Nanocrystalline ceramic materials

Science.gov (United States)

Siegel, Richard W.; Nieman, G. William; Weertman, Julia R.

1994-01-01

A method for preparing a treated nanocrystalline metallic material. The method of preparation includes providing a starting nanocrystalline metallic material with a grain size less than about 35 nm, compacting the starting nanocrystalline metallic material in an inert atmosphere and annealing the compacted metallic material at a temperature less than about one-half the melting point of the metallic material.

Superconductive B-doped nanocrystalline diamond thin films: Electrical transport and Raman spectra

Czech Academy of Sciences Publication Activity Database

Nesládek, M.; Tromson, D.; Mer, Ch.; Bergonzo, P.; Hubík, Pavel; Mareš, Jiří J.

2006-01-01

Roč. 88, č. 23 (2006), 232111/1-232111/3 ISSN 0003-6951 R&D Projects: GA ČR(CZ) GA202/06/0040 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystalline diamond * superconductivity * magnetoresistance * Raman spectroscopy * Fano resonance Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.977, year: 2006

Resolving the nanostructure of plasma-enhanced chemical vapor deposited nanocrystalline SiOx layers for application in solar cells

Science.gov (United States)

Klingsporn, M.; Kirner, S.; Villringer, C.; Abou-Ras, D.; Costina, I.; Lehmann, M.; Stannowski, B.

2016-06-01

Nanocrystalline silicon suboxides (nc-SiOx) have attracted attention during the past years for the use in thin-film silicon solar cells. We investigated the relationships between the nanostructure as well as the chemical, electrical, and optical properties of phosphorous, doped, nc-SiO0.8:H fabricated by plasma-enhanced chemical vapor deposition. The nanostructure was varied through the sample series by changing the deposition pressure from 533 to 1067 Pa. The samples were then characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, Raman spectroscopy, aberration-corrected high-resolution transmission electron microscopy, selected-area electron diffraction, and a specialized plasmon imaging method. We found that the material changed with increasing pressure from predominantly amorphous silicon monoxide to silicon dioxide containing nanocrystalline silicon. The nanostructure changed from amorphous silicon filaments to nanocrystalline silicon filaments, which were found to cause anisotropic electron transport.

Radiative recombination in doped indium phosphide crystals

International Nuclear Information System (INIS)

Negreskul, V.V.; Russu, E.V.; Radautsan, S.I.; Cheban, A.G.; AN Moldavskoj SSR, Kishinev. Inst. Prikladnoj Fiziki)

1975-01-01

Photoluminiscence spectra of nondoped n-InP and their change upon doping with silicon, cadmium, zinc and copper impurities were studied. The shortest wave band at 1.41 eV is connected with radiative electron transition from a shallow donor level (probably silicon) to valent zone, while the band with maximum at 1.37 - 1.39 eV is due to radiative electron transition to an acceptor level whose energy depends upon the nature and concentration of impurity implanted. The luminescence of Light-doped p-InP crystals enables to estimate the ionization energies of acceptor levels in cadmium (Esub(a)=0.043 eV) and zinc (Esub(a)=0.027 eV). Energies of acceptor levels (0.22 and 0.40 eV) due to copper impurity are determined. Intensity of edge emission in the specimens light-doped with silicon is higher than in the nondoped n-InP crystals

Ethanol dehydration on doped cadmium oxide

International Nuclear Information System (INIS)

Abd El-Salaam, K.M.

1975-01-01

The vapour phase catalytic dehydration of ethanol over Fe impregnated cadmium oxide was investigated between 200-450 0 C in atmospheric pressure. Electron transfer mechanisms involved in adsorption and catalytic dehydration reaction were investigated. The change in electrical conductivity of the catalyst resulting from calcination, adsorption and surface reaction processes were studied. Adsorption conductivity at low temperature ( 0 C) indicates that ethanol adsorbs as an electron donor. A mechanism of creation of interstitial Cd atoms responsible for the catalytic dehydration of ethanol on the catalyst surface was suggested. (orig.) [de

Optical and Electrical Properties of Tin-Doped Cadmium Oxide Films Prepared by Electron Beam Technique

Science.gov (United States)

Ali, H. M.; Mohamed, H. A.; Wakkad, M. M.; Hasaneen, M. F.

2009-04-01

Tin-doped cadmium oxide films were deposited by electron beam evaporation technique. The structural, optical and electrical properties of the films were characterized. The X-ray diffraction (XRD) study reveals that the films are polycrystalline in nature. As composition and structure change due to the dopant ratio and annealing temperature, the carrier concentration was varied around 1020 cm-3, and the mobility increased from less than 10 to 45 cm2 V-1 s-1. A transmittance value of ˜83% and a resistivity value of 4.4 ×10-4 Ω cm were achieved for (CdO)0.88(SnO2)0.12 film annealed at 350 °C for 15 min., whereas the maximum value of transmittance ˜93% and a resistivity value of 2.4 ×10-3 Ω cm were obtained at 350 °C for 30 min. The films exhibited direct band-to-band transitions, which corresponded to optical band gaps of 3.1-3.3 eV.

Diodes of nanocrystalline SiC on n-/n+-type epitaxial crystalline 6H-SiC

Science.gov (United States)

Zheng, Junding; Wei, Wensheng; Zhang, Chunxi; He, Mingchang; Li, Chang

2018-03-01

The diodes of nanocrystalline SiC on epitaxial crystalline (n-/n+)6H-SiC wafers were investigated, where the (n+)6H-SiC layer was treated as cathode. For the first unit, a heavily boron doped SiC film as anode was directly deposited by plasma enhanced chemical vapor deposition method on the wafer. As to the second one, an intrinsic SiC film was fabricated to insert between the wafer and the SiC anode. The third one included the SiC anode, an intrinsic SiC layer and a lightly phosphorus doped SiC film besides the wafer. Nanocrystallization in the yielded films was illustrated by means of X-ray diffraction, transmission electronic microscope and Raman spectrum respectively. Current vs. voltage traces of the obtained devices were checked to show as rectifying behaviors of semiconductor diodes, the conduction mechanisms were studied. Reverse recovery current waveforms were detected to analyze the recovery performance. The nanocrystalline SiC films in base region of the fabricated diodes are demonstrated as local regions for lifetime control of minority carriers to improve the reverse recovery properties.

Synthesis of cadmium oxide doped ZnO nanostructures using electrochemical deposition

International Nuclear Information System (INIS)

Singh, Trilok; Pandya, D.K.; Singh, R.

2011-01-01

Research highlights: → Ternary ZnCdO alloy semiconductor nanostructures were grown using electrochemical deposition. → X-ray diffraction measurements showed that the nanostructures were of wurtzite structure and possessed a compressive stress along the c-axis direction. → The cut-off wavelength shifted from blue to red on account of the Cd incorporation in the ZnO and the average transmittance decreased by ∼31%. → The bandgap tuning for 4-16 at% Cd in the initial solution was achieved in the range of 3.08-3.32 eV (up to 0.24 eV). - Abstract: Ternary ZnCdO alloy semiconductor nanostructures were grown using electrochemical deposition. Crystalline nanostructures/nanorods with cadmium concentration ranging from 4 to 16 at% in the initial solution were electrodeposited on tin doped indium oxide (ITO) conducting glass substrates at a constant cathodic potential -0.9 V and subsequently annealed in air at 300 deg. C. X-ray diffraction measurements showed that the nanostructures were of wurtzite structure and possessed a compressive stress along the c-axis direction. The elemental composition of nanostructures was confirmed by energy dispersive spectroscopy (EDS). ZnO nanostructures were found to be highly transparent and had an average transmittance of 85% in the visible range of the spectrum. After the incorporation of Cd content into ZnO the average transmittance decreased and the bandgap tuning was also achieved.

Chemical Bath Deposition of PbS:Hg2+ Nanocrystalline Thin Films

Directory of Open Access Journals (Sweden)

R. Palomino-Merino

2013-01-01

Full Text Available Nanocrystalline PbS thin films were prepared by Chemical Bath Deposition (CBD at 40 ± 2°C onto glass substrates and their structural and optical properties modified by in-situ doping with Hg. The morphological changes of the layers were analyzed using SEM and the X-rays spectra showing growth on the zinc blende (ZB face. The grain size determined by using X-rays spectra for undoped samples was found to be ~36 nm, whereas with the doped sample was 32–20 nm. Optical absorption spectra were used to calculate the Eg, showing a shift in the range 1.4–2.4 eV. Raman spectroscopy exhibited an absorption band ~135 cm−1 displaying only a PbS ZB structure.

Nanocrystalline solids

International Nuclear Information System (INIS)

Gleiter, H.

1991-01-01

Nanocrystalline solids are polycrystals, the crystal size of which is a few (typically 1 to 10) nanometres so that 50% or more of the solid consists of incoherent interfaces between crystals of different orientations. Solids consisting primarily of internal interfaces represent a separate class of atomic structures because the atomic arrangement formed in the core of an interface is known to be an arrangement of minimum energy in the potential field of the two adjacent crystal lattices with different crystallographic orientations on either side of the boundary core. These boundary conditions result in atomic structures in the interfacial cores which cannot be formed elsewhere (e.g. in glasses or perfect crystals). Nanocrystalline solids are of interest for the following four reasons: (1) Nanocrystalline solids exhibit an atomic structure which differs from that of the two known solid states: the crystalline (with long-range order) and the glassy (with short-range order). (2) The properties of nanocrystalline solids differ (in some cases by several orders of magnitude) from those of glasses and/or crystals with the same chemical composition, which suggests that they may be utilized technologically in the future. (3) Nanocrystalline solids seem to permit the alloying of conventionally immiscible components. (4) If small (1 to 10 nm diameter) solid droplets with a glassy structure are consolidated (instead of small crystals), a new type of glass, called nanoglass, is obtained. Such glasses seem to differ structurally from conventional glasses. (orig.)

Synthesis of cadmium tungstate films via sol-gel processing

Energy Technology Data Exchange (ETDEWEB)

Lennstrom, Kirk; Limmer, Steven J.; Cao Guozhong

2003-06-23

Cadmium tungstate is a scintillator material with excellent intrinsic photoluminescent properties. It is highly resistant to gamma radiation, has an almost non-existent afterglow and is highly efficient. Cadmium tungstate is also non-hydroscopic, unlike the more prevalent thallium-doped alkali halide scintillators. In order to create thin films of cadmium tungstate with precise stoichiometric control, a sol-gel processing technique has been applied to produce this material for the first time. In addition to lower processing temperatures, sol-gel-derived cadmium tungstate is cheaper and easier than other technologies, particularly for thin films. Furthermore, it has the potential to produce nanostructured materials with good optical quality. X-Ray diffraction results of sol-gel-derived materials fired at various temperatures imply crystallization of cadmium tungstate without the intermediate formation of either tungsten oxide or cadmium oxide. Scanning electron microscopy analysis shows the formation of nano-sized particles prior to heat treatment, which form meso-sized particles after the heat treatment. Photoluminesce analysis indicates emission of derived films at 480 nm, which agrees with other published data. Finally, the efficiency of derived films was approximately 6%{+-}1.8%.

Properties of Nitrogen-Doped Zinc Telluride Films for Back Contact to Cadmium Telluride Photovoltaics

Science.gov (United States)

Shimpi, Tushar M.; Drayton, Jennifer; Swanson, Drew E.; Sampath, Walajabad S.

2017-08-01

Zinc telluride (ZnTe) films have been deposited onto uncoated glass superstrates by reactive radiofrequency (RF) sputtering with different amounts of nitrogen introduced into the process gas, and the structural and electronic transport properties of the resulting nitrogen-doped ZnTe (ZnTe:N) films characterized. Based on transmission and x-ray diffraction measurements, it was observed that the crystalline quality of the ZnTe:N films decreased with increasing nitrogen in the deposition process. The bulk carrier concentration of the ZnTe:N films determined from Hall-effect measurements showed a slight decrease at 4% nitrogen flow rate. The effect of ZnTe:N films as back contact to cadmium telluride (CdTe) solar cells was also investigated. ZnTe:N films were deposited before or after CdCl2 passivation on CdTe/CdS samples. Small-area devices were characterized for their electronic properties. Glancing-angle x-ray diffraction measurements and energy-dispersive spectroscopy analysis confirmed substantial loss of zinc from the samples where CdCl2 passivation was carried out after ZnTe:N film deposition.

Non-destructive local determination of doping additions and main components in single crystals

International Nuclear Information System (INIS)

Ehksperiandova, L.P.; Blank, A.B.; Kukhtina, N.N.; Afanasiadi, L.I.

1994-01-01

Procedures for local non-destructive determination of elements in optical and scintillation single crystals are developed. They are applied for determination of the main components (in cadmium tungstate) and doping additions (tellurium in zinc selenide, europium in gadolinium silicate). The metrological characteristics of the developed micro-analysis methods are estimated. Segregation of the main components and doping additions in the objects under consideration are investigated. Tellurium is found to be distributed uniformly on the cross-sections of bulk zinc selenide single crystals. The segregation of europium along gadolinium silicate ingots is almost absent. On the cross-section surface of cadmium tungstate single crystals the microregions are found characterized by the prevailing contents of cadmium or tungsten

Physical properties of Fe doped Mn3O4 thin films synthesized by SILAR method and their antibacterial performance against E. coli

Directory of Open Access Journals (Sweden)

M.R. Belkhedkar

2016-09-01

Full Text Available Nanocrystalline Fe doped Mn3O4 thin films were deposited by successive ionic layer adsorption and reaction method onto glass substrates. The X-ray diffraction study revealed that Fe doped Mn3O4 films are nanocrystalline in nature. The morphological investigations were carried out by using field emission scanning electron and atomic force microscopy studies. The optical absorption measurements showed that Mn3O4 films exhibit direct band gap energy of the order of 2.78 eV and it increased to 2.89 eV as the percentage of Fe doping in it increases from 0 to 8 wt.%. The room temperature electrical resistivity of Mn3O4 increases from 1.84 × 103 to 2.64 × 104 Ω cm as Fe doping increases from 0 to 8 wt.%. The SILAR grown Mn3O4 showed antibacterial performance against Escherichia coli bacteria which improved remarkably with doping.

Study of hybrid solar cells made of multilayer nanocrystalline titania and poly(3-octylthiophene) or poly-(3-(2-methylhex-2-yl)-oxy-carbonyldithiophene)

DEFF Research Database (Denmark)

Antoniadou, Maria; Stathatos, Elias; Boukos, Nikolaos

2009-01-01

Hybrid solar cells have been constructed by using nanocrystalline titania and hole-transporting polymers. Titania was deposited on fluorine-doped tin-oxide transparent electrodes in three layers: a blocking layer and two nanostructured layers, giving densely packed or open structures. Open...

Upconversion and pump saturation mechanisms in Er3+/Yb3+ co-doped Y2Ti2O7 nanocrystals

International Nuclear Information System (INIS)

Wang, Fengxiao; Song, Feng; Zhang, Gong; Han, Yingdong; Li, Qiong; Tian, Jianguo; Ming, Chengguo

2014-01-01

The Er 3+ /Yb 3+ co-doped Y 2 Ti 2 O 7 nanocrystals were synthesized by the sol–gel method. X-ray diffraction, transmission electronic microscopy, and photoluminescence spectra were measured to verify the Y 2 Ti 2 O 7 nanocrystalline produced in the sample annealed at 800 °C. The anomalous slopes of the fitted line in the log-log plots for upconversion emissions and the pump-saturation effect of near-infrared emission were observed in the nanocrystalline samples. A theoretical model of practical Er 3+ /Yb 3+ co-doped system based on the rate equations were put forward and explained the experimental phenomena well

Rise time spectroscopy in cadmium telluride detectors

International Nuclear Information System (INIS)

Scharager, Claude; Siffert, Paul; Carnet, Bernard; Le Meur, Roger.

1980-11-01

By a simultaneous analysis of rise time and pulse amplitude distributions of the signals issued from various cadmium telluride detectors, it is possible to obtain informations about surface and bulk trapping, field distribution within the detectors, as well as charge collection and transport properties. These investigations have been performed on both pure and chlorine doped and materials for various surfaces preparation conditions [fr

Photocatalytic removal of NO and HCHO over nanocrystalline Zn2SnO4 microcubes for indoor air purification

International Nuclear Information System (INIS)

Ai Zhihui; Lee Shuncheng; Huang Yu; Ho Wingkei; Zhang Lizhi

2010-01-01

Nanocrystalline Zn 2 SnO 4 microcubes were hydrothermally synthesized and systematically characterized by XRD, SEM, TEM, XPS, N 2 adsorption-desorption, and UV-vis DRS analysis. The resulting Zn 2 SnO 4 microcubes with the edge size ranging from 0.8 to 1.2 μm were composed of numerous nanoparticles with size of 10-20 nm, and their optical band gap energy was estimated to be 3.25 eV from the UV-vis diffuse reflectance spectra. On degradation of nitrogen monoxide (NO) and formaldehyde (HCHO) at typical concentrations for indoor air quality, these nanocrystalline Zn 2 SnO 4 microcubes exhibited superior photocatalytic activity to the hydrothermally synthesized ZnO, SnO 2 , and Degussa TiO 2 P25, as well as C doped TiO 2 under UV-vis light irradiation. This enhanced photocatalytic activity of the nanocrystalline Zn 2 SnO 4 microcubes was attributed to their bigger surface areas, smaller particle size, special porous structures, and special electronic configuration. The nanocrystalline Zn 2 SnO 4 microcubes were chemically stable as there was no obvious deactivation during the multiple photocatalytic reactions. This work presents a promising approach for scaling-up industrial production of Zn 2 SnO 4 nanostructures and suggests that the synthesized nanocrystalline Zn 2 SnO 4 microcubes are promising photocatalysts for indoor air purification.

Structural, Optical and Ethanol Sensing Properties of Dy-Doped SnO2 Nanoparticles

Science.gov (United States)

Shaikh, F. I.; Chikhale, L. P.; Nadargi, D. Y.; Mulla, I. S.; Suryavanshi, S. S.

2018-04-01

We report a facile co-precipitation synthesis of dysprosium (Dy3+) doped tin oxide (SnO2) thick films and their use as gas sensors. The doping percentage (Dy3+) was varied from 1 mol.% to 4 mol.% with the step of 1 mol.%. As-produced material with varying doping levels were sintered in air; and by using a screen printing technique, their thick films were developed. Prior to sensing performance investigations, the films were examined for structural, morphological and compositional properties using x-ray diffraction, a field emission scanning electron microscope, a transmission electron microscope, selected area electron diffraction, energy dispersive analysis by x-rays, Fourier transform infrared spectroscopy and Raman spectroscopic techniques. The structural analyses revealed formation of single phase nanocrystalline material with tetragonal rutile structure of SnO2. The morphological analyses confirmed the nanocrystalline porous morphology of as-developed material. Elemental analysis defined the composition of material in accordance with the doping concentration. The produced sensor material exhibited good response towards different reducing gases (acetone, ethanol, LPG, and ammonia) at different operating temperatures. The present study confirms that the Dy3+ doping in SnO2 enhances the response towards ethanol with reduction in operating temperature. Particularly, 3 mol.% Dy3+ doped sensor exhibited the highest response (˜ 92%) at an operating temperature of 300°C with better selectivity, fast response (˜ 13 s) and recovery (˜ 22 s) towards ethanol.

Characterization of boron doped nanocrystalline diamonds

International Nuclear Information System (INIS)

Peterlevitz, A C; Manne, G M; Sampaio, M A; Quispe, J C R; Pasquetto, M P; Iannini, R F; Ceragioli, H J; Baranauskas, V

2008-01-01

Nanostructured diamond doped with boron was prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, hydrogen and argon mixture. The reduction of the diamond grains to the nanoscale was produced by secondary nucleation and defects induced by argon and boron atoms via surface reactions during chemical vapour deposition. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains, while morphological investigations using field electron scanning microscopy show that the size of the grains ranges from 20 to 100 nm. The lowest threshold fields achieved were in the 1.6 to 2.4 V/μm range

Chemical bath deposition of CdS thin films doped with Zn and Cu

Indian Academy of Sciences (India)

Abstract. Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ... Cadmium sulfide; chemical bath deposition; doping; optical window. 1. ..... at low temperature (10 K), finding similar trends than.

Effect of noble metal doping on the structural properties of lanthanum cobaltite

International Nuclear Information System (INIS)

Dharmadhikari, Dipti V.; Athawal, Anjali A.

2016-01-01

Pristine and Noble metal (Ag and Pd) doped lanthanum cobaltite samples have been synthesised by Hydrothermal method. Lanthanum in the A-Site and Co at B-site of Lanthanum cobaltite (LaCoO 3 ) perovskites were partially doped by silver and palladium (4%). Crystal structure analysis revealed that the hydrothermal synthesis led to the formation of pure nanocrystalline perovskite structure. Morphological analysis of the samples shows that the noble metal doping affects the morphology of the samples. Pristine sample shows spherical to oval shaped particles while the doping results in the formation of irregular shaped, spherical and rod shaped particles. Silver doping results in the agglomeration of particles. The particles were observed to be fused with each other to form rod shaped structures in case of palladium doped samples. (author)

Role of grain size in superconducting boron-doped nanocrystalline diamond thin films grown by CVD

Czech Academy of Sciences Publication Activity Database

Zhang, G.; Janssens, S.D.; Vanacken, J.; Timmermans, M.; Vacík, Jiří; Ataklti, G.W.; Decelle, W.; Gillijns, W.; Goderis, B.; Haenen, K.; Wagner, P.; Moshchalkov, V.V.

2011-01-01

Roč. 84, č. 21 (2011), 214517/1-214517/10 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10480505 Keywords : Nanocrystalline diamond * Superconducting transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

Optical and structural characterization of KBr crystals doped cadmium bromide (CdBr2)

International Nuclear Information System (INIS)

Bensouici, A.; Plaza, J.L.; Dieguez, E.; Halimi, O.; Guerbous, L.; Sebais, M.

2010-01-01

In this paper we demonstrate the presence of CdBr 2 and cadmium aggregates in KBr matrix during Czochralski growth of KBr crystals. The chemical decomposition of CdBr 2 due to high temperature of crystallisation and reformation of cadmium bromide seems to be responsible for this effect.

Thermally Stable Nanocrystalline Steel

Science.gov (United States)

Hulme-Smith, Christopher Neil; Ooi, Shgh Woei; Bhadeshia, Harshad K. D. H.

2017-10-01

Two novel nanocrystalline steels were designed to withstand elevated temperatures without catastrophic microstructural changes. In the most successful alloy, a large quantity of nickel was added to stabilize austenite and allow a reduction in the carbon content. A 50 kg cast of the novel alloy was produced and used to verify the formation of nanocrystalline bainite. Synchrotron X-ray diffractometry using in situ heating showed that austenite was able to survive more than 1 hour at 773 K (500 °C) and subsequent cooling to ambient temperature. This is the first reported nanocrystalline steel with high-temperature capability.

Structural, optical and magnetic characterization of Ru doped ZnO nanorods

International Nuclear Information System (INIS)

Kumar, Sanjeev; Kaur, Palvinder; Chen, C.L.; Thangavel, R.; Dong, C.L.; Ho, Y.K.; Lee, J.F.; Chan, T.S.; Chen, T.K.; Mok, B.H.; Rao, S.M.; Wu, M.K.

2014-01-01

Graphical abstract: Ruthenium (Ru = 0%, 1% and 2%) doped nano-crystalline zinc oxide (ZnO) nanorods were synthesized by using well-known sol–gel technique. X-ray diffraction (XRD) results show that Ru (0%, 1% and 2%) doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). Williamson and Hall plot reveal that in the nanoscale dimensions, incorporation of Ru induced the tensile strain in ZnO host matrix. Photoluminescence (PL) and Raman studies of Ru doped ZnO nanorods show the formation of singly ionized oxygen vacancies which may account for the observed room temperature ferromagnetism (RTFM) in 2% Ru doped ZnO. X-ray absorption spectroscopy (XAS) reveals that Ru replace the Zn atoms in the host lattice and maintain the crystal symmetry with slightly lattice distortion. Highlights: • Ru doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). • PL and Raman studies show the formation of singly ionized oxygen vacancies in 2% Ru doped ZnO. • XAS reveals that Ru replace the Zn atoms in the host lattice with slightly lattice distortion. • Doping of Ru in ZnO nanostructures gives rise to RTFM ordering. -- Abstract: Ruthenium (Ru = 0%, 1% and 2%) doped nano-crystalline zinc oxide (ZnO) nanorods were synthesized by using well-known sol–gel technique. X-ray diffraction (XRD) results show that Ru (0%, 1% and 2%) doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). Williamson and Hall plot reveal that in the nanoscale dimensions, incorporation of Ru induced the tensile strain in ZnO host matrix. Photoluminescence (PL) and Raman studies of Ru doped ZnO nanorods show the formation of singly ionized oxygen vacancies which may account for the observed room temperature ferromagnetism (RTFM) in 2% Ru doped ZnO. X-ray absorption spectroscopy (XAS) reveals that Ru replace the Zn atoms in the host lattice and maintain the crystal symmetry with slightly lattice

Synthesis of Nanocrystalline SnO2 Modified TiO2:a Material for Carbon Monoxide Gas Sensor

Directory of Open Access Journals (Sweden)

A. B. BODADE

2008-11-01

Full Text Available Nanocrystalline SnO2 doped TiO2 having average crystallite size of 45-50 nm were synthesized by the sol-gel method and studied for gas sensing behavior to reducing gases like CO, liquefied petroleum gas (LPG, NH3 and H2. The material characterization was done by using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and scanning electron microscope (SEM. The sensitivity measurements were carried out as a function of different operating temperature in SnO2 doped TiO2. The 15 wt.% SnO2 doped TiO2 based CO sensor shows better sensitivity at an operating temperature 240°C Incorporation of 0.5 wt% Pd improved the sensitivity, selectivity, response time and reduced the operating temperature from 240°C to 200°C for CO sensor.

Doping properties of cadmium-rich arsenic-doped CdTe single crystals: Evidence of metastable AX behavior

Science.gov (United States)

Nagaoka, Akira; Kuciauskas, Darius; Scarpulla, Michael A.

2017-12-01

Cd-rich composition and group-V element doping are of interest for simultaneously maximizing the hole concentration and minority carrier lifetime in CdTe, but the critical details concerning point defects are not yet fully established. Herein, we report on the properties of arsenic doped CdTe single crystals grown from Cd solvent by the travelling heater method. The photoluminescence spectra and activation energy of 74 ± 2 meV derived from the temperature-dependent Hall effect are consistent with AsTe as the dominant acceptor. Doping in the 1016 to 1017/cm3 range is achieved for measured As concentrations between 1016 and 1020/cm3 with the highest doping efficiency of 40% occurring near 1017 As/cm3. We observe persistent photoconductivity, a hallmark of light-induced metastable configuration changes consistent with AX behavior. Additionally, quenching experiments reveal at least two mechanisms of increased p-type doping in the dark, one decaying over 2-3 weeks and the other persisting for at least 2 months. These results provide essential insights for the application of As-doped CdTe in thin film solar cells.

Enhancement of the power factor in two-phase silicon-boron nanocrystalline alloys

Energy Technology Data Exchange (ETDEWEB)

Narducci, Dario; Lorenzi, Bruno [Department of Materials Science, University of Milano Bicocca, Milan (Italy); Zianni, Xanthippe [Department of Aircraft Technologies, Technological Educational Institution of Sterea Ellada, Psachna (Greece); Department of Microelectronics, IAMPPNM, NCSR Demokritos, Athens (Greece); Neophytou, Neophytos [Institute for Microelectronics, TUV, Vienna (Austria); School of Engineering, University of Warwick, Coventry (United Kingdom); Frabboni, Stefano [Department of FIM, University of Modena and Reggio Emilia, Modena (Italy); CNR-Institute of Nanoscience-S3, Modena (Italy); Gazzadi, Gian Carlo [CNR-Institute of Nanoscience-S3, Modena (Italy); Roncaglia, Alberto; Suriano, Francesco [IMM-CNR, Bologna (Italy)

2014-06-15

In previous publications it was shown that the precipitation of silicon boride around grain boundaries may lead to an increase of the power factor in nanocrystalline silicon. Such an effect was further explained by computational analyses showing that the formation of an interphase at the grain boundaries along with high boron densities can actually lead to a concurrent increase of the electrical conductivity σ and of the Seebeck coefficient S. In this communication we report recent evidence of the key elements ruling such an unexpected effect. Nanocrystalline silicon films deposited onto a variety of substrates were doped to nominal boron densities in excess of 10{sup 20} cm{sup -3} and were annealed up to 1000 C to promote boride precipitation. Thermoelectric properties were measured and compared with their microstructure. A concurrent increase of σ and S with the carrier density was found only upon formation of an interphase. Its dependency on the film microstructure and on the deposition and processing conditions will be discussed. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Photocatalytic properties of nanocrystalline TiO2 thin film with Ag additions

International Nuclear Information System (INIS)

Chang, C.-C.; Lin, C.-K.; Chan, C.-C.; Hsu, C.-S.; Chen, C.-Y.

2006-01-01

In the present study, nanocrystalline TiO 2 /Ag composite thin films were prepared by a sol-gel spin coating technique. While, by introducing polystyrene (PS) microspheres, porous TiO 2 /Ag films were obtained after calcining at a temperature of 500 o C. The as-prepared TiO 2 and TiO 2 /Ag thin films were characterized by X-ray diffractometry, and scanning electron microscopy to reveal the structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methylene blue under UV irradiation. After 500 o C calcination, the microstructure of PS-TiO 2 film without Ag addition exhibited a sponge-like microstructure while significant sintering effect was noticed with Ag additions and the films exhibited a porous microstructure. Meanwhile, coalescence of nanocrystalline anatase-phase TiO 2 can be observed with respect to the sharpening of XRD diffraction peaks. The photodegradation of porous TiO 2 doped with 1 mol% Ag exhibited the best photocatalytic efficiency where 72% methylene blue can be decomposed after UV exposure for 12 h

Spectroscopic and radiative properties study of Nd3+ doped cadmium-phosphate glasses

International Nuclear Information System (INIS)

Mahmoud, K.H.

2010-01-01

A spectroscopic investigation is performed on Nd 3+ doped cadmium-phosphate glasses. The Judd-Ofelt analysis is applied to the glass system in order to evaluate their potential as both glass laser and amplifier materials. The phenomenological Judd-Ofelt parameters Ω (2) , Ω (4) , and Ω (6) are determined, their values are 4.80x10 -20 , 6.18x10 -20 , and 7.14x10 -20 cm -2 , respectively. The quality factor for glass system is 0.86. Predicted radiative decay rates and branching ratios of transitions from Nd 3+4 F 3/2 state to the 4 I J manifolds are determined and analyzed. The calculated lifetime of the 4 F 3/2 metastable state of Nd 3+ is 31 μs. The results showed that 4 F 3/2 to 4 I 11/2 transition, with fluorescence at 1056 nm, has the most potential for laser application. Photoluminescence up-conversion under excitation at 488 nm laser light exhibits three emission bands of Nd 3+ ions at 541 (green), 601 (orange), and 677 nm (red). These emission bands are assigned to 4 G 7/2 → 4 I 9/2 , 4 G 7/2 → 4 I 11/2 , and 4 G 7/2 → 4 I 13/2 transitions, respectively. Analysis of luminescence spectra enhances the use of glass system in optical displays, lasers, and optical memory devices.

Structural properties of silver doped hydroxyapatite and their biocompatibility

International Nuclear Information System (INIS)

Ciobanu, C.S.; Iconaru, S.L.; Pasuk, I.; Vasile, B.S.; Lupu, A.R.; Hermenean, A.; Dinischiotu, A.; Predoi, D.

2013-01-01

The aim of this study was to obtain a novel hydroxyapatite-based material with high biocompatibility. The structural properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The X-ray diffraction studies revealed the characteristic peaks of hydroxyapatite in each sample. Other phases or impurities were not observed. The scanning electron microscopy observations suggest that the doping components have no influence on the surface morphology of the samples, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O) and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) and X-ray Photoelectron Spectroscopy analyses. Nanocrystalline silver doped HAp stimulated viability and potentiated the activation of murine macrophages. - Highlights: ► A simple and low cost methodology to obtain Ag:HAp powders was described in this paper. ► Nanocrystalline Ag:HAp with different x Ag from can be obtained at 100 °C by co-precipitation. ► The study aims to understand the effects of Ag:HAp NPs with different x Ag on macrophage cells

Simultaneous determination of oxygen and cadmium in cadmium and cadmium compounds

International Nuclear Information System (INIS)

Imaeda, K.; Kuriki, T.; Ohsawa, K.; Ishii, Y.

1977-01-01

Cadmium and its compounds were analysed for oxygen and cadmium by a modification of the Schutze-Unterzaucher method. Oxygen in some compounds such as cadmium oxide, nitrate and sulphate could not be determined by the usual method. The method of adding carbon was employed for the determination of total oxygen. Total oxygen could be determined by the addition of 5 mg of carbon to a sample boat and heating at 950 0 . The determination was also carried out by addition of naphthalene (2 mg). It was found that the cadmium powder and cadmium flake used contained ca. 1 and 0.15% oxygen, respectively. Oxygen and cadmium in cadmium and its compounds were simultaneously determined by the addition of 2 mg of naphthalene. Cadmium was determined colorimetrically by use of glyoxal-bis-(2-hydroxyanil). Oxygen and cadmium in the samples could be determined simultaneously with an average error of -0.02 and -0.22%, respectively. (author)

Optical and structural characterization of KBr crystals doped cadmium bromide (CdBr{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Bensouici, A., E-mail: bensouicia@yahoo.f [Laboratory of Crystallography (Saint Lucia), Department of Physics, Mentouri-Constantine University, Constantine (Algeria); Plaza, J.L., E-mail: joseluis.plaza@uam.e [Crystal Growth Laboratory (CGL), Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Madrid (Spain); Dieguez, E. [Crystal Growth Laboratory (CGL), Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Madrid (Spain); Halimi, O. [Laboratory of Crystallography (Saint Lucia), Department of Physics, Mentouri-Constantine University, Constantine (Algeria); Guerbous, L. [Centre de recherche nucleaire d' Alger (CRNA), Alger 16000 (Algeria); Sebais, M. [Laboratory of Crystallography (Saint Lucia), Department of Physics, Mentouri-Constantine University, Constantine (Algeria)

2010-04-15

In this paper we demonstrate the presence of CdBr{sub 2} and cadmium aggregates in KBr matrix during Czochralski growth of KBr crystals. The chemical decomposition of CdBr{sub 2} due to high temperature of crystallisation and reformation of cadmium bromide seems to be responsible for this effect.

Epitaxially grown zinc-blende structured Mn doped ZnO nanoshell on ZnS nanoparticles

International Nuclear Information System (INIS)

Limaye, Mukta V.; Singh, Shashi B.; Date, Sadgopal K.; Gholap, R.S.; Kulkarni, Sulabha K.

2009-01-01

Zinc oxide in the bulk as well as in the nanocrystalline form is thermodynamically stable in the wurtzite structure. However, zinc oxide in the zinc-blende structure is more useful than that in the wurtzite structure due to its superior electronic properties as well as possibility of efficient doping. Therefore, zinc oxide shell is grown epitaxially on zinc sulphide core nanoparticles having zinc-blende structure. It is shown that doping of manganese could be achieved in zinc oxide nanoshell with zinc-blende structure

Ag-doped CdO nanocatalysts: Preparation, characterization and catechol oxidase activity

Science.gov (United States)

El-Kemary, Maged; El-Mehasseb, Ibrahim; El-Shamy, Hany

2018-06-01

Silver doped cadmium oxide (Ag/CdO) nanoparticles with an average size of 41 nm have been successfully synthesized via thermal decomposition and liquid impregnation technique. The structural characterization has been performed by using several spectroscopic techniques, e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier-transform infrared (FT-IR). The catechol oxidase has been studied by UV-visible absorption spectroscopy and fourier-transform infrared as well as the mechanism has been assured by cyclic voltammetry and fluorescence spectroscopy. The results indicate that the oxidation does not occur in the presence of unsupported cadmium oxide particles by silver and in the same time, the catechol oxidase activity of silver doped CdO nanoparticles were improved by about three orders of magnitude than silver ions.

Structural, electrical and optical studies of SILAR deposited cadmium oxide thin films: Annealing effect

International Nuclear Information System (INIS)

Salunkhe, R.R.; Dhawale, D.S.; Gujar, T.P.; Lokhande, C.D.

2009-01-01

Successive ionic layer adsorption and reaction (SILAR) method has been successfully employed for the deposition of cadmium oxide (CdO) thin films. The films were annealed at 623 K for 2 h in an air and changes in the structural, electrical and optical properties were studied. From the X-ray diffraction patterns, it was found that after annealing, H 2 O vapors from as-deposited Cd(O 2 ) 0.88 (OH) 0.24 were removed and pure cubic cadmium oxide was obtained. The as-deposited film consists of nanocrystalline grains of average diameter about 20-30 nm with uniform coverage of the substrate surface, whereas for the annealed film randomly oriented morphology with slight increase in the crystallite size has been observed. The electrical resistivity showed the semiconducting nature with room temperature electrical resistivity decreased from 10 -2 to 10 -3 Ω cm after annealing. The decrease in the band gap energy from 3.3 to 2.7 eV was observed after the annealing

Combustion synthesis and photoluminescence in novel red emitting yttrium gadolinium pyrosilicate nanocrystalline phosphor

Energy Technology Data Exchange (ETDEWEB)

Hedaoo, V.P., E-mail: vraikwar@rediffmail.com [Department of Physics, R. J. College, Ghatkopar, Mumbai, MS 400086 (India); Bhatkar, V.B. [Department of Physics, Shri Shivaji Science College, Amravati, MS 444602 (India); Omanwar, S.K. [Department of Physics, SGB Amravati University, Amravati, MS 444602 (India)

2016-07-05

Yttrium Gadolinium Pyrosilicate Y{sub 2-x}Gd{sub x}Si{sub 2}O{sub 7}:Eu{sup 3+} (x = 0.05, 0.10, 0.15) phosphor powder was prepared by facile and time efficient modified combustion method for the first time. The phosphor was characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence excitation (PLE) and emission (PL) spectroscopy and color chromaticity coordinates. XRD revealed the monoclinic crystal structure with space group P1¯. The crystallite size was calculated by Williamson-Hall (W–H) analysis. Nanoplates-like morphology was observed in FESEM analysis with size in the range 50–80 nm. TEM images confirmed the particle size and shape. Upon excitation by 254 nm UV light, the phosphor showed the characteristic red emission peaks at 589 nm and 613 nm corresponding to {sup 5}D{sub 0} → {sup 7}F{sub 1} and {sup 5}D{sub 0} → {sup 7}F{sub 2} transitions respectively. It was observed that the nanocrystalline phosphor Y{sub 2-x}Gd{sub x}Si{sub 2}O{sub 7}:Eu{sup 3+}can be tuned to emit orange to red color by adjusting the ratio Y/Gd. This phosphor thus can be a potential candidate as orange to red color emitting tunable nanocrystalline phosphor for optical devices. - Highlights: • A novel Yttrium Gadolinium Pyrosilicate doped with Eu{sup 3+} is reported. • Facile and time efficient modified combustion method is used. • The nanocrystalline structure was shown by X-ray diffraction, W–H analysis. • FESEM and TEM images confirmed the nanocrystalline structure. • The reported phosphor can be tuned from orange to red by varying Y/Gd ratio.

Infrared luminescence and thermoluminescence of lithium borate glasses doped with Sm3+ ions

Directory of Open Access Journals (Sweden)

Anjaiah J.

2015-03-01

Full Text Available Thermoluminescence (TL characteristics of X-ray irradiated pure and doped with Sm3+ ions Li2O-MO-B2O3 (where MO=ZnO, CaO, CdO glasses have been studied in the temperature range of 303 to 573 K. All the pure glasses exhibited single TL peaks at 382 K, 424 K and 466 K. When these glasses were doped with Sm3+ ions no additional peaks have been observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve was found to be maximum for Sm3+ doped glasses mixed with cadmium oxide as a modifier. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen’s formulae. The possible use of these glasses in radiation dosimetry has been described. The results clearly showed that samarium doped cadmium borate glass has a potential to be considered as a thermoluminescence dosimeter.

Nanocrystalline diamond films for biomedical applications

DEFF Research Database (Denmark)

Pennisi, Cristian Pablo; Alcaide, Maria

2014-01-01

Nanocrystalline diamond films, which comprise the so called nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD), represent a class of biomaterials possessing outstanding mechanical, tribological, and electrical properties, which include high surface smoothness, high corrosion...... performance of nanocrystalline diamond films is reviewed from an application-specific perspective, covering topics such as enhancement of cellular adhesion, anti-fouling coatings, non-thrombogenic surfaces, micropatterning of cells and proteins, and immobilization of biomolecules for bioassays. In order...

Strength and structure of nanocrystalline titanium

International Nuclear Information System (INIS)

Noskova, N.I.; Pereturina, I.A.; Elkina, O.A.; Stolyarov, V.V.

2004-01-01

Investigation results on strength and plasticity of nanocrystalline titanium VT-1 are presented. Specific features of plastic deformation on tension of this material specimens in an electron microscope column are studied in situ. It is shown that nanocrystalline titanium strength and plasticity at room temperature are dependent on the structure and nanograin size. It is revealed that deformation processes in nanocrystalline titanium are characterized by activation of deformation rotational modes and microtwinning [ru

Studying Structural, Optical, Electrical, and Sensing Properties of Nanocrystalline SnO2:Cu Films Prepared by Sol-Gel Method for CO Gas Sensor Application at Low Temperature

Science.gov (United States)

Al-Jawad, Selma M. H.; Elttayf, Abdulhussain K.; Saber, Amel S.

Nanocrystalline SnO2 and SnO2:Cu thin films derived from SnCl2ṡ2H2O precursors have been prepared on glass substrates using sol-gel dip-coating technique. The deposited film was 300±20nm thick and the films were annealed in air at 500∘C for 1h. Structural, optical and sensing properties of the films were studied under different preparation conditions, such as Cu-doping concentration of 2%, 4% and 6wt.%. X-ray diffraction studies show the polycrystalline nature with tetragonal rutile structure of SnO2 and Cu:SnO2 thin films. The films have highly preferred orientation along (110). The crystallite size of the prepared samples reduced with increasing Cu-doping concentrations and the addition of Cu as dopants changed the structural properties of the thin films. Surface morphology was determined through scanning electron microscopy and atomic force microscopy. Results show that the particle size decreased as doping concentration increased. The films have moderate optical transmission (up to 82.4% at 800nm), and the transmittance, absorption coefficient and energy gap at different Cu-doping concentration were measured and calculated. Results show that Cu-doping decreased the transmittance and energy gap whereas it increased the absorption coefficient. Two peaks were noted with Cu-doping concentration of 0-6wt.%; the first peak was positioned exactly at 320nm ultraviolet emission and the second was positioned at 430-480nm. Moreover, emission bands were noticed in the photoluminescence spectra of Cu:SnO2. The electrical properties of SnO2 films include DC electrical conductivity, showing that the films have two activation energies, namely, Ea1 and Ea2, which increase as Cu-doping concentration increases. Cudoped nanocrystalline SnO2 gas-sensing material has better sensitivity to CO gas compared with pure SnO2.

Bulk and nanocrystalline electron doped Gd0.15Ca0.85MnO3: Synthesis and magnetic characterization

Science.gov (United States)

Dhal, Lakshman; Chattarpal; Nirmala, R.; Santhosh, P. N.; Kumary, T. Geetha; Nigam, A. K.

2014-09-01

Polycrystalline Gd0.15Ca0.85MnO3 sample was prepared by solid state reaction method and nanocrystalline samples of different grain sizes of the same were prepared by sol-gel method. Phase purity and composition were verified by room temperature X-ray diffraction and SEM-EDAX analysis. Magnetization data of bulk Gd0.15Ca0.85MnO3 in 5 kOe field shows a peak at 119 K (TN) suggesting an antiferromagnetic transition. Nanocrystalline Gd0.15Ca0.85MnO3 sample ( 54 nm size) also shows a cusp at 107 K and a broad thermal hysteresis between field cooled cooling (FCC) and field cooled warming (FCW) data around this temperature. This thermal hysteresis suggests possible crystal structural transition. Field variation of magnetization of bulk Gd0.15Ca0.85MnO3 at 5 K shows a tendency to saturate, but yields a magnetic moment value of only 1.12 μB/f.u. in 70 kOe. The value of magnetization of nanocrystalline sample at 5 K in 70 kOe field is slightly larger and is 1.38 μB/f.u. which is probably due to the surface moments of the nanoparticle samples. Both the samples show Curie-Weiss-like behaviour in their paramagnetic state.

Comparative investigation on cation-cation (Al-Sn) and cation-anion (Al-F) co-doping in RF sputtered ZnO thin films: Mechanistic insight

Energy Technology Data Exchange (ETDEWEB)

Mallick, Arindam; Basak, Durga, E-mail: sspdb@iacs.res.in

2017-07-15

Highlights: • Comparative study on Al, Al-Sn and Al-F doped ZnO films has been carried out. • High transparent Al-F co-doped film shows three times enhanced carrier density. • Al-F co-doped film shows larger carrier relaxation time. • Al-Sn co-doped films shows carrier transport dominated by impurity scattering. • Al-F co-doped ZnO film can be applied as transparent electrode. - Abstract: Herein, we report a comparative mechanistic study on cation-cation (Al-Sn) and cation-anion (Al-F) co-doped nanocrystalline ZnO thin films grown on glass substrate by RF sputtering technique. Through detailed analyses of crystal structure, surface morphology, microstructure, UV-VIS-NIR transmission-reflection and electrical transport property, the inherent characteristics of the co-doped films were revealed and compared. All the nanocrystalline films retain the hexagonal wurtzite structure of ZnO and show transparency above 90% in the visible and NIR region. As opposed to expectation, Al-Sn (ATZO) co-doped film show no enhanced carrier concentration consistent with the probable formation of SnO{sub 2} clusters supported by the X-ray photoelectron spectroscopy study. Most interestingly, it has been found that Al-F (AFZO) co-doped film shows three times enhanced carrier concentration as compared to Al doped and Al-Sn co-doped films attaining a value of ∼9 × 10{sup 20} cm{sup −3} due to the respective cation and anion substitution. The carrier relaxation time increases in AFZO while it decreases significantly for ATZO film consistent with the concurrence of the impurity scattering in the latter.

Effect of doping concentration on the structural, morphological, optical and electrical properties of Mn-doped CdO thin films

Directory of Open Access Journals (Sweden)

Manjula N.

2015-12-01

Full Text Available Thin films of manganese-doped cadmium oxide (CdO:Mn with different Mn-doping levels (0, 1, 2, 3 and 4 at.% were deposited on glass substrates by employing an inexpensive, simplified spray technique using a perfume atomizer at 375 °C. The influence of Mn incorporation on the structural, morphological, optical and electrical properties of CdO films has been studied. All the films exhibit cubic crystal structure with a (1 1 1 preferential orientation. Mn-doping causes a slight shift of the (1 1 1 diffraction peak towards higher angle. The crystallite size of the films is found to decrease from 34.63 nm to 17.68 nm with an increase in Mn doping concentration. The CdO:Mn film coated with 1 at.% Mn exhibit a high transparency of nearly 90 % which decreases for higher doping concentration. The optical band gap decreases with an increase in Mn doping concentration. All the films have electrical resistivity of the order of 10−4 Ω·cm.

Characteristic analysis on the physical properties of nanostructured Mg-doped CdO thin films—Doping concentration effect

Directory of Open Access Journals (Sweden)

K. Usharani

2015-06-01

Full Text Available Highly conductive and transparent magnesium-doped cadmium oxide (CdO:Mg thin films have been deposited on suitably cleaned glass substrates maintained at 375 °C by spray pyrolysis technique using perfume atomizer. The magnesium content in the films is varied from 0 to 8 at% in steps of 2 at%. The effect of Mg doping on the structural, morphological, optical and electrical properties of the CdO thin films has been studied. All the films exhibited cubic structure with a preferential orientation along the (1 1 1 plane irrespective of the Mg doping level. SEM analysis showed that the film morphology modifies from spherical shaped grains to closely packed cauliflower shaped nanostructures with Mg doping. Except for the film coated with 2 at% Mg dopant, all the other doped films exhibited a blue shift in the optical band gap. Electrical studies revealed that the CdO:Mg film coated with 8 at% Mg dopant had a minimum resistivity of 0.0853×101 Ω-cm.

Structural and physical properties of antibacterial Ag-doped nano-hydroxyapatite synthesized at 100°C

Science.gov (United States)

Ciobanu, Carmen Steluta; Massuyeau, Florian; Constantin, Liliana Violeta; Predoi, Daniela

2011-12-01

Synthesis of nanosized particle of Ag-doped hydroxyapatite with antibacterial properties is in the great interest in the development of new biomedical applications. In this article, we propose a method for synthesized the Ag-doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionized water. Other phase or impurities were not observed. Silver-doped hydroxyapatite nanoparticles (Ag:HAp) were performed by setting the atomic ratio of Ag/[Ag + Ca] at 20% and [Ca + Ag]/P as 1.67. The X-ray diffraction studies demonstrate that powders made by co-precipitation at 100°C exhibit the apatite characteristics with good crystal structure and no new phase or impurity is found. The scanning electron microscopy (SEM) observations suggest that these materials present a little different morphology, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O), and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) analysis. FT-IR and FT-Raman spectroscopies revealed that the presence of the various vibrational modes corresponds to phosphates and hydroxyl groups. The strain of Staphylococcus aureus was used to evaluate the antibacterial activity of the Ca10- x Ag x (PO4)6(OH)2 ( x = 0 and 0.2). In vitro bacterial adhesion study indicated a significant difference between HAp ( x = 0) and Ag:HAp ( x = 0.2). The Ag:Hap nanopowder showed higher inhibition.

Solid state consolidation nanocrystalline copper-tungsten using cold spray

Energy Technology Data Exchange (ETDEWEB)

Hall, Aaron Christopher [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sarobol, Pylin [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Argibay, Nicolas [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Clark, Blythe [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Diantonio, Christopher [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

It is well known that nanostructured metals can exhibit significantly improved properties compared to metals with conventional grain size. Unfortunately, nanocrystalline metals typically are not thermodynamically stable and exhibit rapid grain growth at moderate temperatures. This severely limits their processing and use, making them impractical for most engineering applications. Recent work has shown that a number of thermodynamically stable nanocrystalline metal alloys exist. These alloys have been prepared as powders using severe plastic deformation (e.g. ball milling) processes. Consolidation of these powders without compromise of their nanocrystalline microstructure is a critical step to enabling their use as engineering materials. We demonstrate solid-state consolidation of ball milled copper-tantalum nanocrystalline metal powder using cold spray. Unfortunately, the nanocrystalline copper-tantalum powder that was consolidated did not contain the thermodynamically stable copper-tantalum nanostructure. Nevertheless, this does this demonstrates a pathway to preparation of bulk thermodynamically stable nanocrystalline copper-tantalum. Furthermore, it demonstrates a pathway to additive manufacturing (3D printing) of nanocrystalline copper-tantalum. Additive manufacturing of thermodynamically stable nanocrystalline metals is attractive because it enables maximum flexibility and efficiency in the use of these unique materials.

Visible sub-band gap photoelectron emission from nitrogen doped and undoped polycrystalline diamond films

Energy Technology Data Exchange (ETDEWEB)

Elfimchev, S., E-mail: sergeyel@tx.technion.ac.il; Chandran, M.; Akhvlediani, R.; Hoffman, A.

2017-07-15

Highlights: • Nitrogen related centers in diamond film are mainly responsible for visible sub-band-gap photoelectron emission. • The influence of film thickness and substrate on the measured photoelectron emission yields was not found. • Nanocrystalline diamonds have low electron emission yields most likely because of high amount of defects. • Visible sub-band gap photoelectron emission may increase with temperature due to electron trapping/detrapping processes. - Abstract: In this study the origin of visible sub-band gap photoelectron emission (PEE) from polycrystalline diamond films is investigated. The PEE yields as a function of temperature were studied in the wavelengths range of 360–520 nm. Based on the comparison of electron emission yields from diamond films deposited on silicon and molybdenum substrates, with different thicknesses and nitrogen doping levels, we suggested that photoelectrons are generated from nitrogen related centers in diamond. Our results show that diamond film thickness and substrate material have no significant influence on the PEE yield. We found that nanocrystalline diamond films have low electron emission yields, compared to microcrystalline diamond, due to the presence of high amount of defects in the former, which trap excited electrons before escaping into the vacuum. However, the low PEE yield of nanocrystalline diamond films was found to increase with temperature. The phenomenon was explained by the trap assisted photon enhanced thermionic emission (ta-PETE) model. According to the ta-PETE model, photoelectrons are trapped by shallow traps, followed by thermal excitation at elevated temperatures and escape into the vacuum. Activation energies of trap levels were estimated for undoped nanocrystalline, undoped microcrystalline and N-doped diamond films using the Richardson-Dushman equation, which gives 0.13, 0.39 and 0.04 eV, respectively. Such low activation energy of trap levels makes the ta-PETE process very

Cadmium carcinogenesis

International Nuclear Information System (INIS)

Waalkes, Michael P.

2003-01-01

Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis

Cadmium carcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Waalkes, Michael P

2003-12-10

Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis.

Antimony doped cadmium selenium nanobelts with enhanced electrical and optoelectrical properties

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lijie [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Yu, Hongfei; Cao, Wei; Dong, Youqing; Zou, Chao; Yang, Yun [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Huang, Shaoming, E-mail: smhuang@wzu.edu.cn [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Dai, Ning [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Zhu, Da-Ming, E-mail: ZhuD@umkc.edu [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); University of Missouri-Kansas City, Kansas City, MO 64110 (United States)

2014-07-01

Intrinsic and Sb-doped CdSe nanobelts (NBs) were synthesized via a thermal evaporation technique. The electrical transport properties of field effect transistors (FETs) fabricated using the NBs were investigated. The results indicate that the Sb-doped NBs behave as n-type semiconductors with improved electrical conductivity (10⁻¹ to 100 S/cm) compared with the intrinsic CdSe. Photodetectors made of single NB were also fabricated and investigated. The results show that Sb-doped NB photodetectors exhibit much higher responsivity (1.5 × 10⁴ A/W) and external quantum efficiency (1.2 × 10⁵) but lower on/off current ratio (~253) and longer response time (≤40 ms). Furthermore, both electrical transport and optoelectrical properties of the as-synthesized CdSe NBs can be tuned by changing the doping concentration. The results indicate that the as-synthesized NBs are excellent building blocks for constructing electronic and optoelectronic devices.

Bilirubin adsorption on nanocrystalline titania films

International Nuclear Information System (INIS)

Yang Zhengpeng; Si Shihui; Fung Yingsing

2007-01-01

Bilirubin produced from hemoglobin metabolism and normally conjugated with albumin is a kind of lipophilic endotoxin, and can cause various diseases when its concentration is high. Bilirubin adsorption on the nanocrystalline TiO 2 films was investigated using quartz crystal microbalance, UV-vis and IR techniques, and factors affecting its adsorption such as pH, bilirubin concentration, solution ionic strength, temperature and thickness of TiO 2 films were discussed. The amount of adsorption and parameters for the adsorption kinetics were estimated from the frequency measurements of quartz crystal microbalance. A fresh surface of the nanocrystalline TiO 2 films could be photochemically regenerated because holes and hydroxyl radicals were generated by irradiating the nanocrystalline TiO 2 films with UV light, which could oxidize and decompose organic materials, and the nanocrystalline TiO 2 films can be easily regenerated when it is used as adsorbent for the removal of bilirubin

Cadmium and Cadmium/Zinc Ratios and Tobacco-Related Morbidities

Science.gov (United States)

Richter, Patricia; Faroon, Obaid; Pappas, R. Steven

2017-01-01

Metals are one of five major categories of carcinogenic or toxic constituents in tobacco and tobacco smoke. Cadmium is highly volatile and a higher percentage of the total tobacco cadmium content is efficiently transferred to mainstream tobacco smoke than many other toxic metals in tobacco. Inhaled cadmium bioaccumulates in the lungs and is distributed beyond the lungs to other tissues, with a total body biological half-life of one to two decades. Chronic cadmium exposure through tobacco use elevates blood and urine cadmium concentrations. Cadmium is a carcinogen, and an inducer of proinflammatory immune responses. Elevated exposure to cadmium is associated with reduced pulmonary function, obstructive lung disease, bronchogenic carcinoma, cardiovascular diseases including myocardial infarction, peripheral arterial disease, prostate cancer, cervical cancer, pancreatic cancer, and various oral pathologies. Cadmium and zinc have a toxicologically inverse relationship. Zinc is an essential element and is reportedly antagonistic to some manifestations of cadmium toxicity. This review summarizes associations between blood, urine, and tissue cadmium concentrations with emphasis on cadmium exposure due to tobacco use and several disease states. Available data about zinc and cadmium/zinc ratios and tobacco-related diseases is summarized from studies reporting smoking status. Collectively, data suggest that blood, urine, and tissue cadmium and cadmium/zinc ratios are often significantly different between smokers and nonsmokers and they are also different in smokers for several diseases and cancers. Additional biomonitoring data such as blood or serum and urine zinc and cadmium levels and cadmium/zinc ratios in smokers may provide further insight into the development and progression of diseases of the lung, cardiovascular system, and possibly other organs. PMID:28961214

Cadmium and Cadmium/Zinc Ratios and Tobacco-Related Morbidities.

Science.gov (United States)

Richter, Patricia; Faroon, Obaid; Pappas, R Steven

2017-09-29

Metals are one of five major categories of carcinogenic or toxic constituents in tobacco and tobacco smoke. Cadmium is highly volatile and a higher percentage of the total tobacco cadmium content is efficiently transferred to mainstream tobacco smoke than many other toxic metals in tobacco. Inhaled cadmium bioaccumulates in the lungs and is distributed beyond the lungs to other tissues, with a total body biological half-life of one to two decades. Chronic cadmium exposure through tobacco use elevates blood and urine cadmium concentrations. Cadmium is a carcinogen, and an inducer of proinflammatory immune responses. Elevated exposure to cadmium is associated with reduced pulmonary function, obstructive lung disease, bronchogenic carcinoma, cardiovascular diseases including myocardial infarction, peripheral arterial disease, prostate cancer, cervical cancer, pancreatic cancer, and various oral pathologies. Cadmium and zinc have a toxicologically inverse relationship. Zinc is an essential element and is reportedly antagonistic to some manifestations of cadmium toxicity. This review summarizes associations between blood, urine, and tissue cadmium concentrations with emphasis on cadmium exposure due to tobacco use and several disease states. Available data about zinc and cadmium/zinc ratios and tobacco-related diseases is summarized from studies reporting smoking status. Collectively, data suggest that blood, urine, and tissue cadmium and cadmium/zinc ratios are often significantly different between smokers and nonsmokers and they are also different in smokers for several diseases and cancers. Additional biomonitoring data such as blood or serum and urine zinc and cadmium levels and cadmium/zinc ratios in smokers may provide further insight into the development and progression of diseases of the lung, cardiovascular system, and possibly other organs.

Electronic transport in mixed-phase hydrogenated amorphous/nanocrystalline silicon thin films

Science.gov (United States)

Wienkes, Lee Raymond

Interest in mixed-phase silicon thin film materials, composed of an amorphous semiconductor matrix in which nanocrystalline inclusions are embedded, stems in part from potential technological applications, including photovoltaic and thin film transistor technologies. Conventional mixed-phase silicon films are produced in a single plasma reactor, where the conditions of the plasma must be precisely tuned, limiting the ability to adjust the film and nanoparticle parameters independently. The films presented in this thesis are deposited using a novel dual-plasma co-deposition approach in which the nanoparticles are produced separately in an upstream reactor and then injected into a secondary reactor where an amorphous silicon film is being grown. The degree of crystallinity and grain sizes of the films are evaluated using Raman spectroscopy and X-ray diffraction respectively. I describe detailed electronic measurements which reveal three distinct conduction mechanisms in n-type doped mixed-phase amorphous/nanocrystalline silicon thin films over a range of nanocrystallite concentrations and temperatures, covering the transition from fully amorphous to ~30% nanocrystalline. As the temperature is varied from 470 to 10 K, we observe activated conduction, multiphonon hopping (MPH) and Mott variable range hopping (VRH) as the nanocrystal content is increased. The transition from MPH to Mott-VRH hopping around 100K is ascribed to the freeze out of the phonon modes. A conduction model involving the parallel contributions of these three distinct conduction mechanisms is shown to describe both the conductivity and the reduced activation energy data to a high accuracy. Additional support is provided by measurements of thermal equilibration effects and noise spectroscopy, both done above room temperature (>300 K). This thesis provides a clear link between measurement and theory in these complex materials.

Study of sterilization-treatment in pure and N- doped carbon thin films synthesized by inductively coupled plasma assisted pulsed-DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Javid, Amjed [Center for Advanced Plasma Surface Technology (CAPST), NU-SKKU Joint Institute for Plasma Nano-Materials (IPNM), Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Textile Processing, National Textile University, Faisalabad 37610 (Pakistan); Kumar, Manish, E-mail: manishk@skku.edu [Center for Advanced Plasma Surface Technology (CAPST), NU-SKKU Joint Institute for Plasma Nano-Materials (IPNM), Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Han, Jeon Geon, E-mail: hanjg@skku.edu [Center for Advanced Plasma Surface Technology (CAPST), NU-SKKU Joint Institute for Plasma Nano-Materials (IPNM), Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2017-01-15

Highlights: • Pure and N-doped nanocrystallie carbon films are synthesized by ICP assisted pulsed DC plasma process. • ICP power induces the increase in average graphitic crystallite size from 4.86 nm to 6.42 nm. • Beneficial role of ICP source assistance to achieve high sputtering throughput (deposition rate ∼55 nm/min). • Post-sterilization electron-transport study shows N-doped carbon films having promising stability. - Abstract: Electrically-conductive nanocrystalline carbon films, having non-toxic and non-immunogenic characteristics, are promising candidates for reusable medical devices. Here, the pure and N- doped nanocrystalline carbon films are deposited by the assistance of inductively coupled plasma (ICP) in an unbalanced facing target pulsed-DC magnetron sputtering process. Through the optical emission spectroscopy study, the role of ICP assistance and N-doping on the reactive components/radicals during the synthesis is presented. The N-doping enhances the three fold bonding configurations by increasing the ionization and energies of the plasma species. Whereas, the ICP addition increases the plasma density to control the deposition rate and film structure. As a result, sputtering-throughput (deposition rate: 31–55 nm/min), electrical resistivity (4–72 Ωcm) and water contact angle (45.12°–54°) are significantly tailored. Electric transport study across the surface microchannel confirms the superiority of N-doped carbon films for sterilization stability over the undoped carbon films.

Benzene oxidation at diamond electrodes: comparison of microcrystalline and nanocrystalline diamonds.

Science.gov (United States)

Pleskov, Yu V; Krotova, M D; Elkin, V V; Varnin, V P; Teremetskaya, I G; Saveliev, A V; Ralchenko, V G

2012-08-27

A comparative study of benzene oxidation at boron-doped diamond (BDD) and nitrogenated nanocrystalline diamond (NCD) anodes in 0.5 M K(2)SO(4) aqueous solution is conducted by using cyclic voltammetry and electrochemical impedance spectroscopy. It is shown by measurements of differential capacitance and anodic current that during the benzene oxidation at the BDD electrode, adsorption of a reaction intermediate occurs, which partially blocks the electrode surface and lowers the anodic current. At the NCD electrode, benzene is oxidized concurrently with oxygen evolution, a (quinoid) intermediate being adsorbed at the electrode. The adsorption and the electrode surface blocking are reflected in the impedance-frequency and impedance-potential complex-plane plots. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gene expression profiling in rat kidney after intratracheal exposure to cadmium-doped nanoparticles

Science.gov (United States)

Coccini, Teresa; Roda, Elisa; Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura; Manzo, Luigi

2012-08-01

While nephrotoxicity of cadmium is well documented, very limited information exists on renal effects of exposure to cadmium-containing nanomaterials. In this work, "omics" methodologies have been used to assess the action of cadmium-containing silica nanoparticles (Cd-SiNPs) in the kidney of Sprague-Dawley rats exposed intratracheally. Groups of animals received a single dose of Cd-SiNPs (1 mg/rat), CdCl2 (400 μg/rat) or 0.1 ml saline (control). Renal gene expression was evaluated 7 and 30 days post exposure by DNA microarray technology using the Agilent Whole Rat Genome Microarray 4x44K. Gene modulating effects were observed in kidney at both time periods after treatment with Cd-SiNPs. The number of differentially expressed genes being 139 and 153 at the post exposure days 7 and 30, respectively. Renal gene expression changes were also observed in the kidney of CdCl2-treated rats with a total of 253 and 70 probes modulated at 7 and 30 days, respectively. Analysis of renal gene expression profiles at day 7 indicated in both Cd-SiNP and CdCl2 groups downregulation of several cluster genes linked to immune function, oxidative stress, and inflammation processes. Differing from day 7, the majority of cluster gene categories modified by nanoparticles in kidney 30 days after dosing were genes implicated in cell regulation and apoptosis. Modest renal gene expression changes were observed at day 30 in rats treated with CdCl2. These results indicate that kidney may be a susceptible target for subtle long-lasting molecular alterations produced by cadmium nanoparticles locally instilled in the lung.

Gene expression profiling in rat kidney after intratracheal exposure to cadmium-doped nanoparticles

International Nuclear Information System (INIS)

Coccini, Teresa; Roda, Elisa; Fabbri, Marco; Sacco, Maria Grazia; Gribaldo, Laura; Manzo, Luigi

2012-01-01

While nephrotoxicity of cadmium is well documented, very limited information exists on renal effects of exposure to cadmium-containing nanomaterials. In this work, “omics” methodologies have been used to assess the action of cadmium-containing silica nanoparticles (Cd-SiNPs) in the kidney of Sprague-Dawley rats exposed intratracheally. Groups of animals received a single dose of Cd-SiNPs (1 mg/rat), CdCl 2 (400 μg/rat) or 0.1 ml saline (control). Renal gene expression was evaluated 7 and 30 days post exposure by DNA microarray technology using the Agilent Whole Rat Genome Microarray 4x44K. Gene modulating effects were observed in kidney at both time periods after treatment with Cd-SiNPs. The number of differentially expressed genes being 139 and 153 at the post exposure days 7 and 30, respectively. Renal gene expression changes were also observed in the kidney of CdCl 2 -treated rats with a total of 253 and 70 probes modulated at 7 and 30 days, respectively. Analysis of renal gene expression profiles at day 7 indicated in both Cd-SiNP and CdCl 2 groups downregulation of several cluster genes linked to immune function, oxidative stress, and inflammation processes. Differing from day 7, the majority of cluster gene categories modified by nanoparticles in kidney 30 days after dosing were genes implicated in cell regulation and apoptosis. Modest renal gene expression changes were observed at day 30 in rats treated with CdCl 2 . These results indicate that kidney may be a susceptible target for subtle long-lasting molecular alterations produced by cadmium nanoparticles locally instilled in the lung.

Synthesis and characterization of Fe doped cadmium selenide thin films by spray pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Yadav, Abhijit A., E-mail: aay_physics@yahoo.co.in [Thin Film Physics Laboratory, Department of Physics, Electronics and Photonics, Rajarshi Shahu Mahavidyalaya, Latur 413 512, Maharashtra (India)

2012-12-05

Highlights: Black-Right-Pointing-Pointer Simple and inexpensive method to dope trivalent Fe in CdSe thin films. Black-Right-Pointing-Pointer Fe doped CdSe thin films are highly photosensitive. Black-Right-Pointing-Pointer AFM analysis shows uniform deposition of film over the entire substrate surface. Black-Right-Pointing-Pointer The band gap energy decreases from 1.74 to 1.65 eV with Fe doping. Black-Right-Pointing-Pointer Film resistivity decreases to 6.76 Multiplication-Sign 10{sup 4} {Omega}-cm with Fe doping in CdSe thin films. - Abstract: Undoped and Fe doped CdSe thin films have been deposited onto the amorphous and fluorine doped tin oxide coated glass substrates by spray pyrolysis. The Fe doping concentration has been optimized by photoelectrochemical (PEC) characterization technique. The structural, surface morphological, compositional, optical and electrical properties of undoped and Fe doped CdSe thin films have been studied. X-ray diffraction study reveals that the as deposited CdSe films possess hexagonal crystal structure with preferential orientation along (1 0 0) plane. AFM analysis shows uniform deposition of the film over the entire substrate surface with minimum surface roughness of 7.90 nm. Direct allowed type of transition with band gap decreasing from 1.74 to 1.65 eV with Fe doping has been observed. The activation energy of the films has been found to be in the range of 0.14-0.19 eV at low temperature and 0.27-0.44 eV at high temperature. Semi-conducting behavior has been observed from resistivity measurements. The thermoelectric power measurements reveal that the films are of n type.

Nanocrystalline hydroxyapatite doped with selenium oxyanions: a new material for potential biomedical applications.

Science.gov (United States)

Kolmas, Joanna; Oledzka, Ewa; Sobczak, Marcin; Nałęcz-Jawecki, Grzegorz

2014-06-01

Selenium-substituted hydroxyapatites containing selenate SeO4(2-) or selenite SeO3(2-) ions were synthesized using a wet precipitation method. The selenium content was determined by atomic absorbance spectrometry. The raw, unsintered powders were also characterized using powder X-ray diffraction, middle-range FT-IR spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopic microanalysis. The synthesized apatites were found to be pure and nanocrystalline with a crystal size similar to that in bone mineral. The incorporation of selenium oxyanions into the crystal lattice was confirmed. The toxicity of hydroxyapatites containing selenite or selenate ions was evaluated with a protozoan assay and bacterial luminescence test. Copyright © 2014 Elsevier B.V. All rights reserved.

Visible and infrared photoluminescence from erbium-doped silicon nanocrystals produced by rf sputtering

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, M.F.; Alpuim, P. [Departamento de Fisica, Universidade do Minho, Braga (Portugal); Losurdo, M. [Plasma Chemistry Research Center, CNR, Bari (Italy); Monteiro, T.; Soares, M.J.; Peres, M. [Departamento de Fisica, Universidade de Aveiro, Aveiro (Portugal); Stepikova, M. [Institute for Physics of Microstructures RAS, 603600 Nizhnij Novgorod GSP-105 (Russian Federation)

2007-06-15

Erbium-doped low-dimensional Si films with different microstructures were deposited by reactive magnetron sputtering on glass substrates by varying the hydrogen flow rate during deposition. Amorphous, micro- and nanocrystalline samples, consisting of Si nanocrystalls embedded in silicon-based matrices with different structures, were achieved with optical properties in the visible and IR depending on nanocrystalline fraction and matrix structure and chemical composition. Structural characterization was performed by X-ray diffraction in the grazing incidence geometry and Raman spectroscopy. The chemical composition was studied using RBS/ERD techniques. Spectroscopic ellipsometry was combined with the previous techniques to further resolve the film microstructure and composition. In particular, the distribution along the film thickness of the volume fractions of nanocrystalline/amorphous silicon and SiO{sub x} phases has been obtained. In this contribution we discuss visible and infrared photoluminescence as a function of sample microstructure and of the oxygen/hydrogen concentration ratio present in the matrix. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electrical and mechanical behavior of polymethyl methacrylate/cadmium sulphide composites

Science.gov (United States)

Kaur, Rajdeep; Samra, Kawaljeet Singh

2018-06-01

In the present investigation, electrical and mechanical behavior of cadmium sulphide (CdS) doped polymethyl methacrylate (PMMA) have been studied using different techniques. Dip casting technique was used for preparing free standing films of pristine and CdS doped PMMA at different compositions (i.e. 1 and 5 wt%). Optical absorbance as a function of wavelength was studied, by UV-visible spectroscopy, to find the impact of CdS doping on the optical band gap of synthesized PMMA/CdS composite. DC and AC conductivities were measured as a function of dopant concentration and temperature. Considerable increase in electrical conductivity was observed with the increase of CdS contents in polymer matrix. Overall electrical conduction mechanism in PMMA/CdS composites was attributed to movement of electrons through the uniformly distributed CdS aggregates within the matrix of PMMA. Mechanical properties, such as Young's modulus, tensile strength, elongation and ductility, of PMMA/CdS composites were determined and relevant responsible phenomena were discussed.

Mn doping in ZnO nanoparticles: effects investigated by positron lifetime and Doppler broadening studies

Energy Technology Data Exchange (ETDEWEB)

Roy, B.; Karmakar, B.; Pal, M. [Department of Physics, University of Burdwan, Golapbag, Burdwan (India); Nambissan, P.M.G. [Saha Institute of Nuclear Physics, Kolkata (India)

2009-11-15

Positron lifetime and Doppler broadening measurements in nanocrystalline zinc oxide (ZnO) indicated the negatively charged trivacancy-type defects V{sub Zn+O+Zn} as the predominant positron trapping sites within the nanocrystallites. They got converted to neutral divacancies (V{sub Zn+O}) on doping with manganese (Mn). Further doping resulted in the reduction of the size of the nanocrystallites. At still increased doping concentrations, a new phase ZnMn{sub 2}O{sub 4} was formed. It had a normal spinel structure with positron trapping centers at some of the tetrahedral and octahedral sites. X-ray diffraction and transmission electron micro-scopy studies confirmed these findings. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Enhancing the photocatalytic activity of nanocrystalline TiO2 by co-doping with fluorine and yttrium

International Nuclear Information System (INIS)

Zhang, Huarong; Miao, Guashuai; Ma, Xingping; Wang, Bei; Zheng, Haiwu

2014-01-01

Highlights: • (F, Y)-codoped TiO 2 nanoparticles were prepared by a simple sol–gel method. • The highest photocatalytic activity (15 times of that over the pure TiO 2 ) was exhibited in the codoped TiO 2 with 0.05% Y doping level. • The Y doping induced oxygen vancancies played a duel role on the photocatalyic activity of the codoped TiO 2 . • The photocatalytic reactive oxygen species are critical to the photocatalytic degradation processes. - Abstract: Fluorine and yttrium codoped TiO 2 nanoparticles were prepared using a simple sol–gel method. The products were characterized with various spectroscopic and analytical techniques to determine their structural, morphological, optical absorption and photocatalytic properties. The results reveal that neither F nor Y doping causes obvious absorption edge shift in TiO 2 . Photoluminescence (PL) emission spectra present that the PL signal is enhanced, suggesting a decrease of photo-generated charge carrier separation efficiency, after the F or Y doping. The synergistic action by the F and Y doping leads to the highest photocatalytic activity for the degradation of methylene blue solution in the 0.05% (F, Y)-codoped sample (15 times of that over the pure TiO 2 ). With the increase of Y doping level, the photocatalytic performance in the codoped samples increases firstly and then decreases. The photocatalytic activity variations after the F and Y doping were interpreted by the formation of photocatalytic reactive oxygen species induced by the dopings

Structural and Mössbauer studies of nanocrystalline Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} particles prepared by mechanical milling

Energy Technology Data Exchange (ETDEWEB)

Widatallah, H. M., E-mail: hishammw@squ.edu.om; Al-Mabsali, F. N.; Al-Hajri, F. S. [Sultan Qaboos University, Physics Department, College of Science (Oman); Khalifa, N. O. [University of Khartoum, Physics Department, Faculty of Science (Sudan); Gismelseed, A. M.; Al-Rawas, A. D.; Elzain, M.; Yousif, A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

2016-12-15

The structure and magnetic properties of spinel-related Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} nanocrystalline particles of the composition Li{sub 0.5}Fe{sub 2.25}Mn{sub 0.1875}O{sub 4}, prepared by milling a pristine sample for different times, were investigated. The average crystallite and particle size, respectively, decreased form ∼40 nm to ∼10 nm and ∼2.5 μm to ∼10 nm with increasing milling time from 0 h to 70 h. Rietveld refinement of the XRD data of the non-milled sample show the Mn{sup 4+} dopant ions to substitute for Fe{sup 3+} at the octahedral B-sites of the spinel-related structure. The Mössbauer spectra of the milled ferrites indicate that more particles turn superparamagnetic with increasing milling time. The Mössbauer data collected at 78 K suggest that while in the non-milled sample the Mn{sup 4+} ions substitute for Fe{sup 3+} at the octahedral B-sites, this is reversed as milling proceeds with doped Mn{sup 4+} ions, balancing Fe{sup 3+} vacancies and possibly Li{sup +} ions progressively migrate to the tetrahedral A-sites. This is supported by the slight increase observed in the magnetization of the milled samples relative to that of the non-milled one. The magnetic data suggest that in addition to the increasing superparamagentic component of the milled particles, thermal spin reversal and/or spin canting effects are possible at the surface layers of the nanoparticles.

Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

International Nuclear Information System (INIS)

Mengui, U.A.; Campos, R.A.; Alves, K.A.; Antunes, E.F.; Hamanaka, M.H.M.O.; Corat, E.J.; Baldan, M.R.

2015-01-01

Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films

Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

Energy Technology Data Exchange (ETDEWEB)

Mengui, U.A., E-mail: ursulamengui@gmail.com [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Campos, R.A.; Alves, K.A.; Antunes, E.F. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Hamanaka, M.H.M.O. [Centro de Tecnologia da Informação Renato Archer, Divisão de Superfícies de Interação e Displays, Rodovia D. Pedro I (SP 65) km 143.6, CP 6162, CEP 13089-500, Campinas, SP (Brazil); Corat, E.J.; Baldan, M.R. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil)

2015-04-15

Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films.

Red shifts of the Eg(1) Raman mode of nanocrystalline TiO2:Er monoliths grown by sol-gel process

Science.gov (United States)

Palomino-Merino, R.; Trejo-Garcia, P.; Portillo-Moreno, O.; Jiménez-Sandoval, S.; Tomás, S. A.; Zelaya-Angel, O.; Lozada-Morales, R.; Castaño, V. M.

2015-08-01

Nanocrystalline monoliths of Er doped TiO2 were prepared by the sol-gel technique, by controlling the Er-doping levels into the TiO2 precursor solution. As-prepared and annealed in air samples showed the anatase TiO2 phase. The average diameter of the nanoparticles ranged from 19 to 2.6 nm as the nominal concentration of Er varies from 0% to 7%, as revealed by EDS analysis in an electron microscope. Photo Acoustic Spectroscopy (PAS) allowed calculate the forbidden band gap, evidencing an absorption edge at around 300 nm, attributed to TiO2 and evidence of electronic transitions or Er3+. The Raman spectra, corresponding to the anatase phase, show the main phonon mode Eg(1) band position at 144 cm-1 with a red shift for the annealing samples.

Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping

KAUST Repository

Wang, Feng

2010-02-25

Doping is a widely applied technological process in materials science that involves incorporating atoms or ions of appropriate elements into host lattices to yield hybrid materials with desirable properties and functions. For nanocrystalline materials, doping is of fundamental importance in stabilizing a specific crystallographic phase, modifying electronic properties, modulating magnetism as well as tuning emission properties. Here we describe a material system in which doping influences the growth process to give simultaneous control over the crystallographic phase, size and optical emission properties of the resulting nanocrystals. We show that NaYF 4 nanocrystals can be rationally tuned in size (down to ten nanometres), phase (cubic or hexagonal) and upconversion emission colour (green to blue) through use of trivalent lanthanide dopant ions introduced at precisely defined concentrations. We use first-principles calculations to confirm that the influence of lanthanide doping on crystal phase and size arises from a strong dependence on the size and dipole polarizability of the substitutional dopant ion. Our results suggest that the doping-induced structural and size transition, demonstrated here in NaYF 4 upconversion nanocrystals, could be extended to other lanthanide-doped nanocrystal systems for applications ranging from luminescent biological labels to volumetric three-dimensional displays. © 2010 Macmillan Publishers Limited. All rights reserved.

Growth of Bi doped cadmium zinc telluride single crystals by Bridgman oscillation method and its structural, optical, and electrical analyses

International Nuclear Information System (INIS)

Carcelen, V.; Rodriguez-Fernandez, J.; Dieguez, E.; Hidalgo, P.

2010-01-01

The II-VI compound semiconductor cadmium zinc telluride (CZT) is very useful for room temperature radiation detection applications. In the present research, we have successfully grown Bi doped CZT single crystals with two different zinc concentrations (8 and 14 at. %) by the Bridgman oscillation method, in which one experiment has been carried out with a platinum (Pt) tube as the ampoule support. Pt also acts as a cold finger and reduces the growth velocity and enhances crystalline perfection. The grown single crystals have been studied with different analysis methods. The stoichiometry was confirmed by energy dispersive by x-ray and inductively coupled plasma mass spectroscopy analyses and it was found there is no incorporation of impurities in the grown crystal. The presence of Cd and Te vacancies was determined by cathodoluminescence studies. Electrical properties were assessed by I-V analysis and indicated higher resistive value (8.53x10 8 Ω cm) for the crystal grown with higher zinc concentration (with Cd excess) compare to the other (3.71x10 5 Ω cm).

Study of high mobility carriers in Ni-doped CdO films

Indian Academy of Sciences (India)

Cadmium oxide (CdO) doped with different amounts of nickel ion thin films have been prepared on silicon and glass .... glass substrate have [111] energetically preferred orientation growth, which is ... Bragg angle of the considered (111) reflection. ... boundaries. .... (figure 3), which means that the grain or crystallite bound-.

Magnetic study of Fe-doped CdSe nanomaterials

International Nuclear Information System (INIS)

Das, Sayantani; Banerjee, Sourish; Sinha, T. P.

2016-01-01

Nanoparticles of pure and iron (50 %) doped cadmium selenide (CdSe) have been synthesized by soft chemical route. EDAX analysis supports the inclusion of Fe into CdSe nanoparticles. The average particle size of pure and doped CdSe is found to be ∼50 nm from scanning electron microscopy (SEM). Magnetization of the samples are measured under the field cooled (FC) and zero field cooled (ZFC) modes in the temperature range from 5K to 300K applying a magnetic field of 500Oe. Field dependent magnetization (M-H) measurement indicates presence of room temperature (RT) paramagnetism and low temperature (5K) ferromagnetism of the sample.

Size dependence of elastic mechanical properties of nanocrystalline aluminum

Energy Technology Data Exchange (ETDEWEB)

Xu, Wenwu; Dávila, Lilian P., E-mail: ldavila@ucmerced.edu

2017-04-24

The effect of grain size on the elastic mechanical properties of nanocrystalline pure metal Al is quantified by molecular dynamics simulation method. In this work, the largest nanocrystalline Al sample has a mean grain size of 29.6 nm and contains over 100 millions atoms in the modeling system. The simulation results show that the elastic properties including elastic modulus and ultimate tensile strength of nanocrystalline Al are relatively insensitive to the variation of mean grain size above 13 nm yet they become distinctly grain size dependent below 13 nm. Moreover, at a grain size <13 nm, the elastic modulus decreases monotonically with decreasing grain size while the ultimate tensile strength of nanocrystalline Al initially decreases with the decrease of the grain size down to 9 nm and then increases with further reduction of grain size. The increase of ultimate tensile strength below 9 nm is believed to be a result of an extended elasticity in the ultrafine grain size nanocrystalline Al. This study can facilitate the prediction of varied mechanical properties for similar nanocrystalline materials and even guide testing and fabrication schemes of such materials.

Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx

International Nuclear Information System (INIS)

Sarah C. Larson; Vicki H. Grassian

2006-01-01

Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the catalytic activity. The reactions of nitrogen dioxides (NO x ) and ammonia (NH 3 ) on nanocrystalline NaY and CuY were investigated using FT-IR spectroscopy. Significant conversion of NO 2 was observed at room temperature in the presence of NH 3 as monitored by FT-IR spectroscopy. Copper-exchanged nanocrystalline NaY was more active for NO 2 reduction with NH 3 relative to nanocrystalline NaY

Metal ion analysis in contaminated water samples using anodic stripping voltammetry and a nanocrystalline diamond thin-film electrode

International Nuclear Information System (INIS)

Sonthalia, Prerna; McGaw, Elizabeth; Show, Yoshiyuki; Swain, Greg M.

2004-01-01

Boron-doped nanocrystalline diamond thin-film electrodes were employed for the detection and quantification of Ag (I), Cu (II), Pb (II), Cd (II), and Zn (II) in several contaminated water samples using anodic stripping voltammetric (ASV). Diamond is an alternate electrode that possesses many of the same attributes as Hg and, therefore, appears to be a viable material for this electroanalytical measurement. The nanocrystalline form has been found to perform slightly better than the more conventional microcrystalline form of diamond in this application. Differential pulse voltammetry (DPASV) was used to detect these metal ions in lake water, well water, tap water, wastewater treatment sludge, and soil. The electrochemical results were compared with data from inductively coupled plasma mass spectrometric (ICP-MS) and or atomic absorption spectrometric (AAS) measurements of the same samples. Diamond is shown to function well in this electroanalytical application, providing a wide linear dynamic range, a low limit of quantitation, excellent response precision, and good response accuracy. For the analysis of Pb (II), bare diamond provided a response nearly identical to that obtained with a Hg-coated glassy carbon electrode

Structure and thermal stability of nanocrystalline materials

Indian Academy of Sciences (India)

In addition, study of the thermal stability of nanocrystalline materials against significant grain growth is both scientific and technological interest. A sharp increase in grain size (to micron levels) during consolidation of nanocrystalline powders to obtain fully dense materials may consequently result in the loss of some unique ...

Synthesis and characterization of nano-crystalline Ce_1-xGd _xO_2-x/2 (x = 0-0.30) solid solutions

DEFF Research Database (Denmark)

Jadhav, L. D.; Chourashiya, M. G.; Jamale, A. P.

2010-01-01

glycine-nitrate process (GNP) has been presented. Evolution of structural and morphological properties of nano-powders as a function of heat treatment has also been studied. The prepared samples were characterized using TG-DTA, FT-IR, Raman spectroscopy, XRD, SEM, etc. In addition, the effect of Gd......In recent years, doped ceria is an established and promising candidate as solid electrolyte for intermediate temperature solid oxide fuel cell (IT-SOFC). In this investigation, synthesis and characterizations of nano-crystalline Gd doped ceria, (Ce1-xGdxO2-x/2, where x = 0-0.3), prepared using...... of sintered samples was observed to hinder with an increase in Gd content....

Review: Plasma-enhanced chemical vapor deposition of nanocrystalline diamond

Directory of Open Access Journals (Sweden)

Katsuyuki Okada

2007-01-01

Full Text Available Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma.

Isolation, identification and cadmium adsorption of a high cadmium ...

African Journals Online (AJOL)

GREGORY

2010-09-27

Sep 27, 2010 ... 1School of Minerals Processing and Bioengineering, Central South University, Changsha, ... Cadmium is a non-essential ... (1994) reported that cadmium might interact ... uptake of cadmium, lead and mercury (Svecova et al.,.

Yttria-doped zirconia as solid electrolyte for fuel-cell applications

Energy Technology Data Exchange (ETDEWEB)

Butz, Benjamin

2009-11-27

7.3-10 mol% yttria-doped zirconia (YDZ) was studied with emphasis on its long-term stability as solid electrolyte. The decomposition of common 8.5YDZ (950 C) was detected by analytical TEM. As second issue, the microstructural and chemical properties of nanocrystalline 7.3YDZ thin films were investigated. Metastable t''-YDZ was found to precipitate in nanoscaled regions in YDZ up to 10 mol% yttria. Furthermore, a revised boundary of the c+t phase field, in which YDZ decomposes, is presented. (orig.)

Yttria-doped zirconia as solid electrolyte for fuel-cell applications

Energy Technology Data Exchange (ETDEWEB)

Butz, Benjamin

2009-11-27

7.3-10 mol% yttria-doped zirconia (YDZ) was studied with emphasis on its long-term stability as solid electrolyte. The decomposition of common 8.5YDZ (950 C) was detected by analytical TEM. As second issue, the microstructural and chemical properties of nanocrystalline 7.3YDZ thin films were investigated. Metastable t''-YDZ was found to precipitate in nanoscaled regions in YDZ up to 10 mol% yttria. Furthermore, a revised boundary of the c+t phase field, in which YDZ decomposes, is presented. (orig.)

Structure and photoluminescence of Mn-passivated nanocrystalline ZnO:S thin films

International Nuclear Information System (INIS)

Tong, Y.H.; Tang, Q.X.; Liu, Y.C.; Shao, C.L.; Xu, C.S.; Liu, Y.X.

2005-01-01

Mn-passivated nanocrystalline ZnO:S thin films were fabricated by thermally oxidizing Mn-doped ZnS (ZnS:Mn) films prepared by electron beam evaporation. Mn was introduced to passivate the surface defects of ZnO and to improve the optical properties. X-ray diffraction (XRD) and photoluminescence (PL) spectra at 81.9 K indicated the S content in ZnO thin film gradually decreased with increasing annealing temperature. The fitted result of the temperature-dependent PL spectra in the range from 81.9 to 302.2 K showed that S dopant could broaden the optical band gap energy of ZnO. Room temperature PL spectra confirmed that the ultraviolet peak shifted to lower energy with the decrease of S content in the thin film because of the Burstein-Moss effect

Possible observation of the Berezinskii-Kosterlitz-Thouless transition in boron-doped diamond films

Science.gov (United States)

Coleman, Christopher; Bhattacharyya, Somnath

2017-11-01

The occurrence of the Berezinskii-Kosterlitz-Thouless (BKT) transition is investigated in heavily boron-doped nanocrystalline diamond films through a combination of current-voltage and resistance measurements. We observe transport features suggesting a robust BKT transition along with transport features related to vortex pinning in nanocrystalline diamond films with smaller grain size. The vortex core energy determined through analysis of the resistance temperature curves was found to be anti-correlated to the BKT transition temperatures. It is also observed that the higher BKT temperature is related to an increased vortex-antivortex binding energy derived from the activated transport regions. Further, the magnetic field induced superconductor insulator transition shows the possibility of the charge glass state. The consequences of granularity such as localization and vortex pinning can lead to tuneable BKT temperatures and strongly affects the field induced insulating state.

Mechanochemical Synthesis of Nanocrystalline CdS in a Laboratory and Industrial Mill

Directory of Open Access Journals (Sweden)

Eberhard Gock

2004-12-01

Full Text Available Nanocrystalline materials have been of interest of more than 20 years and this interest is still increasing. The preparation and characterization of different chalcogenides have attracted a considerable attention due to their important nonlinear properties, luminiscent properties and other important physical and chemical properties. The main cause is in their unusual properties based on the high concentration of atoms in interfacial structures and the relatively simple ways of their preparation. Nanoparticles of semiconductors have many potential applications in the area of advanced materials. These materials can be synthesized via solid state reactions where the recovery degree can be strongly enhanced by the intervention of mechanical activation. Mechanochemical synthesis belongs among the synthesis route which can effectively control and regulate the course of solid state reactions.This paper describes structural and surface properties of cadmium sulphide nanoparticles synthesized in a planetary mill and in an eccentric vibratory mill. The main aim of this paper was to illustrate the potential of this technique for the large-scale production of CdS nanopowder.CdS nanoparticles were successfully synthesized by the mechanochemical route from the cadmium acetate and natrium sulphide. Structure properties of the as-prepared products were characterized by X-ray powder diffraction. X-ray diffraction patterns reveal the crystalline nature of CdS nanoparticles. Hexagonal ƒ¿-CdS greenockite together with cubic hawleyite ƒÀ-CdS are present among the products of mechanochemical synthesis. The methods of SEM, particle size analysis and low temperature nitrogen sorption were used to analyze the surface composition. The SEM measurements show the aggregates of small nanocrystals in which particle sizes of 5-9 nm were estimated by ScherrerLs formula.The cadmium sulphide nanoparticles are obtained in the simple step, making the process attractive for

The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli

2007-01-01

Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems

The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

Energy Technology Data Exchange (ETDEWEB)

Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Korin, Eli [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)

2007-07-15

Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems.

Bimodal microstructure and deformation of cryomilled bulk nanocrystalline Al-7.5Mg alloy

International Nuclear Information System (INIS)

Lee, Z.; Witkin, D.B.; Radmilovic, V.; Lavernia, E.J.; Nutt, S.R.

2005-01-01

The microstructure, mechanical properties and deformation response of bimodal structured nanocrystalline Al-7.5Mg alloy were investigated. Grain refinement was achieved by cryomilling of atomized Al-7.5Mg powders, and then cryomilled nanocrystalline powders blended with 15 and 30% unmilled coarse-grained powders were consolidated by hot isostatic pressing followed by extrusion to produce bulk nanocrystalline alloys. Bimodal bulk nanocrystalline Al-7.5Mg alloys, which were comprised of nanocrystalline grains separated by coarse-grain regions, show balanced mechanical properties of enhanced yield and ultimate strength and reasonable ductility and toughness compared to comparable conventional alloys and nanocrystalline metals. The investigation of tensile and hardness test suggests unusual deformation mechanisms and interactions between ductile coarse-grain bands and nanocrystalline regions

Infrared absorption study of hydrogen incorporation in thick nanocrystalline diamond films

International Nuclear Information System (INIS)

Tang, C.J.; Neves, A.J.; Carmo, M.C.

2005-01-01

We present an infrared (IR) optical absorbance study of hydrogen incorporation in nanocrystalline diamond films. The thick nanocrystalline diamond films were synthesized by microwave plasma-assisted chemical vapor deposition and a high growth rate about 3.0 μm/h was achieved. The morphology, phase quality, and hydrogen incorporation were assessed by means of scanning electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Large amount of hydrogen bonded to nanocrystalline diamond is clearly evidenced by the huge CH stretching band in the FTIR spectrum. The mechanism of hydrogen incorporation is discussed in light of the growth mechanism of nanocrystalline diamond. This suggests the potential of nanocrystalline diamond for IR electro-optical device applications

[Investigation of urinary cadmium reference of general population in two rural high background areas of soil cadmium and non-cadmium-polluted in China].

Science.gov (United States)

Han, Jingxiu; Li, Qiujuan; Yao, Dancheng; Zheng, Jiangang; Zhang, Wenli; Shang, Qi

2014-09-01

To study the reference of urinary. cadmium of the general population in rural high background areas of soil cadmium and non-cadmium contaminated in China. In rural high background areas of soil cadmium and non-cadmium contaminated, randomly selected non-occupational-cadmium exposed population 1134 people (male 519, female 615) with each gender and age groups, questionnaire surveyed and collected random urine. Urinary cadmium and urinary creatinine (Cr) concentration were tested, excluding urinary Cr 3 g/L. Analyze the impact factors of urinary cadmium and calculated 95% quantile (P,95 ) of urinary cadmium after correction by urinary Cr. Female median urinary cadmium was significantly higher than men, male smokers median urinary cadmium was significantly higher than male non-smokers (P 30 year-old. According to gender, and 15 -30, 30 years old, analysis the upper limit of cadmium in urine. The 95% upper limit of urinary cadmium of 30 year-old female (12.24 microg/gCr) was significantly higher than other populations ( population exceeded the upper limit (5 microg/gCr) of the occupational cadmium poisoning diagnostic criteria in China (GBZ 17-2002). In the two rural high background areas of soil cadmium and non-cadmium polluted , urinary cadmium reference of non-cadmium-occupational-exposed male is <9.0 microg/gCr, and female <13.0 microg/gCr.

FEM numerical analysis of excimer laser induced modification in alternating multi-layers of amorphous and nano-crystalline silicon films

International Nuclear Information System (INIS)

Conde, J.C.; Martín, E.; Stefanov, S.; Alpuim, P.; Chiussi, S.

2012-01-01

Highlights: ► nc-Si:H is a material with growing importance for a large-area of nano-electronic, photovoltaic or biomedical devices. ► UV-ELA technique causes a rapid heating that provokes the H 2 desorption from the Si surface and bulk material. ► Next, diffusion of P doped nc-Si films and eventually, for high energy densities would be possible to reach the melting point. ► These multilayer structures consisting of thin alternating a-Si:H(10 nm) and n-doped nc-Si:H(60 nm) films deposited on SiO 2 . ► To optimize parameters involved in this processing, FEM numerical analysis of multilayer structures have been performed. ► The numerical results are compared with exhaustive characterization of the experimental results. - Abstract: UV excimer laser annealing (UV-ELA) is an alternative annealing process that, during the last few years, has gained enormous importance for the CMOS nano-electronic technologies, with the ability to provide films and alloys with electrical and optical properties to fit the desired device performance. The UV-ELA of amorphous (a-) and/or doped nano-crystalline (nc-) silicon films is based on the rapid (nanoseconds) formation of temperature profiles caused by laser radiation that is absorbed in the material and lead to crystallisation, diffusion in solid or even in liquid phase. To achieve the desired temperature profiles and to optimize the parameters involved in the processing of hydrogenated nanocrystalline silicon (nc-Si:H) films with the UV-ELA, a numerical analysis by finite element method (FEM) of a multilayer structure has been performed. The multilayer structures, consisting of thin alternating a-Si:H(10 nm) and n-doped nc-Si:H(60 nm) layers, deposited on a glass substrate, has also been experimentally analyzed. Temperature profiles caused by 193 nm radiation with 25 ns pulse length and energy densities ranging from 50 mJ/cm 2 to 400 mJ/cm 2 have been calculated. Numerical results allowed us to estimate the dehydrogenation

Nanostructured rare earth doped Nb2O5: Structural, optical properties and their correlation with photonic applications

International Nuclear Information System (INIS)

Pereira, Rafael Ramiro; Aquino, Felipe Thomaz; Ferrier, Alban; Goldner, Philippe; Gonçalves, Rogéria R.

2016-01-01

In the present work, we report on a systematic study on structural and spectroscopic properties Eu 3+ and Er 3+ -doped Nb 2 O 5 prepared by sol–gel method. The Eu 3+ ions were used as structural probe to determine the symmetry sites occupied by lanthanide ions. The Eu 3+ -doped Nb 2 O 5 nanocrystalline powders were annealed at different temperatures to verify how the different Nb 2 O 5 crystalline phases affect the structure and the luminescence properties. Er 3+ -doped Nb 2 O 5 was prepared showing an intense NIR luminescence, and, visible luminescence on the green and red, deriving from upconversion process. The synthetized materials can find widespread applicability in photonics as red luminophor for white LED (with tricolor), optical amplifiers and upconverter materials. - Highlights: • Vis and NIR emission from nanostructured lanthanide doped Nb 2 O 5 . • Eu 3+ -doped Nb 2 O 5 as Red luminophor. • Multicolor tunability of intense upconversion emission from lanthanide doped Nb 2 O 5 . • Potential application as biological markers. • Broad band NIR emission.

Phosphates nanoparticles doped with zinc and manganese for sunscreens

Energy Technology Data Exchange (ETDEWEB)

Araujo, T.S. de, E-mail: tatiana.araujo@ifs.edu.br [Departamento de Fisica, Universidade Federal de Sergipe, Sergipe (Brazil); Instituto Federal de Ciencias e Tecnologia de Sergipe, Sergipe (Brazil); Souza, S.O. de [Departamento de Fisica, Universidade Federal de Sergipe, Sergipe (Brazil); Miyakawa, W. [Divisao de Fotonica - Instituto de Estudos Avancados, Sao Jose dos Campos (Brazil); Sousa, E.M.B. de [Centro de Desenvolvimento de Tecnologia Nuclear - CDTN/CNEN, Minas Gerais (Brazil)

2010-12-01

The crescent number of skin cancer worldwide gives impulse to the development of sunscreen that can both prevent skin cancer and also permit gradual tanning. In this work, the synthesis of hydroxyapatite and tricalcium phosphate nanocrystalline powders was investigated in order to obtain materials with optical properties and appropriate size for sunscreen. Pure, Zn{sup 2+}-doped and Mn{sup 2+}-doped hydroxyapatite (HAP) and tricalcium phosphate ({beta}-TCP) were produced by the wet precipitation process using diammonium phosphate, calcium nitrate, ammonium hydroxide, zinc nitrate and manganese nitrate as reagents. The pure and doped HAP precipitates were calcined at 500 deg. C for 1 h, while the {beta}-TCP (pure and doped) were calcined at 800 deg. C for 2 h. The powder samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDX), atomic force microscopy (AFM) and ultraviolet (UV)-vis spectroscopy. XRD and EDX showed the formation of the expected materials (HAP and {beta}-TCP) without toxic components. AFM micrographs showed aggregated ellipsoidal particles with dimensions smaller than 120 nm. Optical absorption spectra showed that the calcium phosphate produced in this work absorbs in the UV region. The obtained materials presented structural, morphological and optical properties that allow their use as the active centers in sunscreens.

Phosphates nanoparticles doped with zinc and manganese for sunscreens

International Nuclear Information System (INIS)

Araujo, T.S. de; Souza, S.O. de; Miyakawa, W.; Sousa, E.M.B. de

2010-01-01

The crescent number of skin cancer worldwide gives impulse to the development of sunscreen that can both prevent skin cancer and also permit gradual tanning. In this work, the synthesis of hydroxyapatite and tricalcium phosphate nanocrystalline powders was investigated in order to obtain materials with optical properties and appropriate size for sunscreen. Pure, Zn 2+ -doped and Mn 2+ -doped hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) were produced by the wet precipitation process using diammonium phosphate, calcium nitrate, ammonium hydroxide, zinc nitrate and manganese nitrate as reagents. The pure and doped HAP precipitates were calcined at 500 deg. C for 1 h, while the β-TCP (pure and doped) were calcined at 800 deg. C for 2 h. The powder samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDX), atomic force microscopy (AFM) and ultraviolet (UV)-vis spectroscopy. XRD and EDX showed the formation of the expected materials (HAP and β-TCP) without toxic components. AFM micrographs showed aggregated ellipsoidal particles with dimensions smaller than 120 nm. Optical absorption spectra showed that the calcium phosphate produced in this work absorbs in the UV region. The obtained materials presented structural, morphological and optical properties that allow their use as the active centers in sunscreens.

Sol–gel glass-ceramics comprising rare-earth doped SnO2 and LaF3 nanocrystals: an efficient simultaneous UV and IR to visible converter

International Nuclear Information System (INIS)

Yanes, A. C.; Castillo, J. del; Méndez-Ramos, J.; Rodríguez, V. D.

2011-01-01

We report a novel class of nanostructured glass-ceramics comprising two co-existing rare-earth doped nanocrystalline phases, SnO 2 semiconductor nanocrystal (quantum dot), and LaF 3 , presenting sizes at around 4.6 and 9.8 nm, respectively, embedded into a silica glass matrix for an efficient simultaneous UV and IR to visible photon conversion. On one hand, the wide and strong UV absorption by SnO 2 quantum dot and subsequent efficient energy transfer to Eu 3+ and, on the other hand, the also very efficient IR to visible up-conversion with the pair Yb 3+ –Er 3+ partitioned into low phonon LaF 3 nanocrystalline environment, yield to visible emissions with application in improving the spectral response of photovoltaic solar cells.Graphical AbstractWe report a novel class of nanostructured glass-ceramics comprising two co-existing rare-earth doped nanocrystalline phases, SnO 2 semiconductor nanocrystal (quantum dot) and LaF 3 , presenting sizes at around 4.6 and 9.8 nm, respectively, embedded into a silica glass matrix for an efficient simultaneous UV and IR to visible photon conversion. On one hand, the wide and strong UV absorption by SnO 2 quantum dot and subsequent efficient energy transfer to Eu 3+ and, on the other hand, the also very efficient IR to visible up-conversion with the pair Yb 3+ –Er 3+ partitioned into low phonon LaF 3 nanocrystalline environment, yield to visible emissions with application in improving the spectral response of photovoltaic solar cells.

Bulk and nanocrystalline electron doped Gd{sub 0.15}Ca{sub 0.85}MnO{sub 3}: Synthesis and magnetic characterization

Energy Technology Data Exchange (ETDEWEB)

Dhal, Lakshman; Chattarpal [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Nirmala, R., E-mail: nirmala@iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Santhosh, P.N. [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Kumary, T. Geetha [CMPD, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Mumbai 400 005 (India)

2014-09-01

Polycrystalline Gd{sub 0.15}Ca{sub 0.85}MnO{sub 3} sample was prepared by solid state reaction method and nanocrystalline samples of different grain sizes of the same were prepared by sol–gel method. Phase purity and composition were verified by room temperature X-ray diffraction and SEM-EDAX analysis. Magnetization data of bulk Gd{sub 0.15}Ca{sub 0.85}MnO{sub 3} in 5 kOe field shows a peak at ∼119 K (T{sub N}) suggesting an antiferromagnetic transition. Nanocrystalline Gd{sub 0.15}Ca{sub 0.85}MnO{sub 3} sample (∼54 nm size) also shows a cusp at ∼107 K and a broad thermal hysteresis between field cooled cooling (FCC) and field cooled warming (FCW) data around this temperature. This thermal hysteresis suggests possible crystal structural transition. Field variation of magnetization of bulk Gd{sub 0.15}Ca{sub 0.85}MnO{sub 3} at 5 K shows a tendency to saturate, but yields a magnetic moment value of only ∼1.12 μ{sub B}/f.u. in 70 kOe. The value of magnetization of nanocrystalline sample at 5 K in 70 kOe field is slightly larger and is ∼1.38 μ{sub B}/f.u. which is probably due to the surface moments of the nanoparticle samples. Both the samples show Curie–Weiss-like behaviour in their paramagnetic state.

Optically transparent boron-doped nanocrystalline diamond films for spectroelectrochemical measurements on different substrates

International Nuclear Information System (INIS)

Sobaszek, M.; Bogdanowicz, R.; Pluciński, J.; Siuzdak, K.; Skowroński, Ł.

2016-01-01

Fabrication process of optically transparent boron nanocrystalline diamond (B- NCD) electrode on silicon and quartz substrate was shown. The B-NCD films were deposited on the substrates using Microwave Plasma Assisted Chemical Vapor Deposition (MWPACVD) at glass substrate temperature of 475 °C. A homogenous, continuous and polycrystalline surface morphology with high sp 3 content in B-NCD films and film thickness depending from substrate in the range of 60-300 nm was obtained. The high refraction index and transparency in visible (VIS) wavelength range was achieved. Moreover, cyclic voltammograms (CV) were recorded to determine reaction reversibility at the B-NCD electrode. CV measurements in aqueous media consisting of 1 mM K 3 [Fe(CN) 6 ] in 0.5 M Na 2 SO 4 demonstrated relatively fast kinetics expressed by a redox peak splitting below 503 mV for B-NCD/silicon and 110 mv for B-NCD/quartz

Magnetism and structure of Cu{sub 2}O{sub 1+x} and 3d-doped TiO{sub 2-x} nanopowders

Energy Technology Data Exchange (ETDEWEB)

Yermakov, A.Ye. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation)]. E-mail: yermakov@imp.uran.ru; Uimin, M.A. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Mysik, A.A. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Vykhodets, V.B. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Kurennykh, T.E. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Sokolov, V.I. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Gaviko, V.S. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Schegoleva, N.N. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Gruzdev, N.B. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation)

2007-03-15

The structural features and magnetic properties of non-stoichiometric nanocrystalline semiconductors Cu{sub 2}O{sub 1+x} and TiO{sub 2-x} doped with 3d-metals were investigated. The nanopowders were obtained by gas-phase synthesis in the oxygen contained argon atmosphere. For nanocrystalline samples Cu{sub 2}O{sub 1+x} with oxygen concentration more than stoichiometry (x>0) magnetic hysteresis properties up to temperatures above room temperature (RT) were discovered. In the case of oxygen deficit in TiO{sub 2-x} on the condition that rutile or anatase structure remains, the magnetic moment value grows and the magnetization curves at RT become nonlinear. On doping TiO{sub 2-x} with cobalt, the magnetic moment value increases without indications of magnetic ordering at RT. In the optical absorption spectra of Cu{sub 2}O{sub 1+x} nanopowders at 77K, the peaks in the range of wavelengths 480 and 460nm were revealed, which are close to peaks at n=1 of the blue and indigo exciton series for Cu{sub 2}O single crystal.

The effect of Sm-doping on optical properties of LaB6 nanoparticles

International Nuclear Information System (INIS)

Chao, Luomeng; Bao, Lihong; Shi, Junjie; Wei, Wei; Tegus, O.; Zhang, Zhidong

2015-01-01

Highlights: • Nanoparticles of Sm-doped LaB 6 have been prepared by solid state reaction. • All samples exhibit high absorbance in NIR range and UV range. • The increase of Sm-doping amount shifts the position of minimum absorptance value. • The optical properties of Sm-doped LaB 6 were interpreted by DFT theory. - Abstract: Nanocrystalline particles of LaB 6 , SmB 6 and Sm-doped LaB 6 have been prepared by a solid-state reaction in order to investigate the optical properties of ternary rare-earth hexaborides. The sizes of prepared nanoparticles range from dozens to more than 200 nm, as confirmed by XRD, SEM and TEM examinations. The optical property concerning the absorption spectra was tested with ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectrum. All samples exhibit high absorbance in NIR range and UV range. The increase of Sm-doping amount shifts the position of minimum absorptance value of LaB 6 to the long-wave direction. Density functional theory (DFT) is employed to interpret the optical properties of Sm-doped LaB 6 , and results indicate that Sm 4f states change the DOS at near Fermi surface of LaB 6 after Sm doping and the reduced number of conduction electrons results into the change of absorption spectra

Dynamic of cadmium accumulation in the internal organs of rats after exposure to cadmium chloride and cadmium sulphide nanoparticules of various sizes

Directory of Open Access Journals (Sweden)

Apykhtina O.L.

2017-06-01

Full Text Available The article presents the results of study of cadmium accumulation in the internal organs of Wistar rats after prolonged intraperitoneal administration of cadmium chloride and cadmium sulphide nanoparticles of 4-6 nm and 9-11 nm in size in a dose of 0.08 mg /kg/day calculated as cadmium. Toxic effects were evaluated after 30 injections (1.5 months, 60 injections (3 months, and 1.5 months after the exposure has been ceased. The results of the study showed that the most intensive accumulation of cadmium was observed in the kidneys and liver of experimental animals, which is due to the peculiarities of the toxicokinetics and the route of administration of cadmium compounds. In the kidneys, spleen and thymus of animals exposed to cadmium sulphide nanoparticles, a greater concentration of cadmium than in the organs of animals exposed to cadmium chloride was found. Cadmium accumulated more intensively in the spleen after exposure to larger nanoparticles, than in the kidneys and thymus. In the liver, heart, aorta and brain significant accumulation was observed after cadmium chloride exposure.

Cadmium and renal cancer

International Nuclear Information System (INIS)

Il'yasova, Dora; Schwartz, Gary G.

2005-01-01

Background: Rates of renal cancer have increased steadily during the past two decades, and these increases are not explicable solely by advances in imaging modalities. Cadmium, a widespread environmental pollutant, is a carcinogen that accumulates in the kidney cortex and is a cause of end-stage renal disease. Several observations suggest that cadmium may be a cause of renal cancer. Methods: We performed a systematic review of the literature on cadmium and renal cancer using MEDLINE for the years 1966-2003. We reviewed seven epidemiological and eleven clinical studies. Results: Despite different methodologies, three large epidemiologic studies indicate that occupational exposure to cadmium is associated with increased risk renal cancer, with odds ratios varying from 1.2 to 5.0. Six of seven studies that compared the cadmium content of kidneys from patients with kidney cancer to that of patients without kidney cancer found lower concentrations of cadmium in renal cancer tissues. Conclusions: Exposure to cadmium appears to be associated with renal cancer, although this conclusion is tempered by the inability of studies to assess cumulative cadmium exposure from all sources including smoking and diet. The paradoxical findings of lower cadmium content in kidney tissues from patients with renal cancer may be caused by dilution of cadmium in rapidly dividing cells. This and other methodological problems limit the interpretation of studies of cadmium in clinical samples. Whether cadmium is a cause of renal cancer may be answered more definitively by future studies that employ biomarkers of cadmium exposure, such as cadmium levels in blood and urine

Quantum effect on the energy levels of Eu2+ doped K2Ca2(SO4)3 nanoparticles.

Science.gov (United States)

Salah, Numan; Habib, Sami S; Khan, Zishan H

2010-09-01

Quantum confinement effect on the energy levels of Eu(2+) doped K(2)Ca(2)(SO(4))(3) nanoparticles has been observed. The broad photoluminescence (PL) emission band of Eu(2+) doped K(2)Ca(2)(SO(4))(3) microcrystalline sample observed at ∼436 nm is found to split into two narrow well resolved bands, located at 422 and 445 nm in the nanostructure form of this material. This has been attributed to the reduction in the crystal field strength of the nanomaterials, which results in widening the energy band gap and splitting the broad 4f(6)5d energy level of Eu(2+). Energy band gap values of the micro and nanocrystalline K(2)Ca(2)(SO(4))(3) samples were also determined by measuring the UV-visible absorption spectra. These values are 3.34 and 3.44 eV for the micro and nanocrystalline samples, respectively. These remarkable results suggest that activators having wide emission bands might be subjected to weak crystal strength via nanostructure materials to modify their electronic transitions. This might prove a powerful technique for producing new-advanced materials for use in the fields of solid state lasers and optoelectronic devises.

Synthesis and electrochemical properties of Ti-doped DLC films by a hybrid PVD/PECVD process

Science.gov (United States)

Jo, Yeong Ju; Zhang, Teng Fei; Son, Myoung Jun; Kim, Kwang Ho

2018-03-01

Low electrical conductivity and poor adhesion to metallic substrates are the main drawbacks of diamond-like carbon (DLC) films when used in electrode applications. In this study, Ti-doped DLC films with various Ti contents were synthesized on metal Ti substrates by a hybrid PVD/PECVD process, where PECVD was used for deposition of DLC films and PVD was used for Ti doping. The effects of the Ti doping ratio on the microstructure, adhesion strength, and electrical and electrochemical properties of the DLC films were systematically investigated. An increase in the Ti content led to increased surface roughness and a higher sp2/sp3 ratio of the Ti-DLC films. Ti atoms existed as amorphous-phase Ti carbide when the Ti doping ratio was less than 2.8 at.%, while the nanocrystalline TiC phase was formed in DLC films when the Ti doping ratio was exceeded 4.0 at.%. The adhesion strength, electrical resistivity, electrochemical activity and reversibility of the DLC films were greatly improved by Ti doping. The influence of Ti doping ratio on the electrical and electrochemical properties of the DLC films were also investigated and the best performance was obtained at a Ti content of 2.8 at.%.

Relative Humidity Sensing Properties Of Cu2O Doped ZnO Nanocomposite

International Nuclear Information System (INIS)

Pandey, N. K.; Tiwari, K.; Tripathi, A.; Roy, A.; Rai, A.; Awasthi, P.

2009-01-01

In this paper we report application of Cu 2 O doped ZnO composite prepared by solid state reaction route as humidity sensor. Pellet samples of ZnO-Cu 2 O nanocrystalline powders with 2, 5 and 10 weight% of Cu 2 O in ZnO have been prepared. Pellets have been annealed at temperatures of 200-500 deg. C and exposed to humidity. It is observed that as relative humidity increases, resistance of the pellet decreases for the humidity from 10% to 90%. Sample with 5% of Cu 2 O doped in ZnO and annealed at 500 deg. C shows best results with sensitivity of 1.50 MΩ/%RH. In this case the hysteresis is low and the reproducibility high, making it the suitable candidate for humidity sensing.

Spectroscopic investigations of nanostructured LiNbO3 doped with Eu3+

International Nuclear Information System (INIS)

Hreniak, D.; Speghini, A.; Bettinelli, M.; Strek, W.

2006-01-01

Structural and optical properties of the sol-gel derived nanocrystalline lithium niobate (LiNbO 3 ) powders doped with Eu 3+ ions have been studied. In particular, the influence of the sizes of nanoparticles controlled by temperature on the structural and luminescence properties has been investigated. Emission bands corresponding to 5 D emission became more resolved with increasing nanocrystal size and changed to a typical Eu 3+ :LiNbO 3 single crystal spectrum for nanocrystals having an average size of more than 40 nm. Nonlinear optical properties of nanostructured LiNbO 3 have been confirmed by simple observation of second harmonic generation effect (SHG). The possibility of using nanostructured LiNbO 3 doped with rare-earth ions as self-doubling elements in integrated optoelectronic devices has been discussed

Room temperature ferromagnetism of nanocrystalline Nd1.90Ni0.10O3-δ

Science.gov (United States)

Sarkar, B. J.; Mandal, J.; Dalal, M.; Bandyopadhyay, A.; Chakrabarti, P. K.

2018-05-01

Nanocrystalline sample of Ni2+ doped neodymium oxide (Nd1.90Ni0.10O3-δ, NNO) is synthesized by co-precipitation method. Analysis of X-ray diffraction (XRD) pattern by Rietveld refinement method confirms the desired phase of NNO and complete substitution of Ni2+ ions in the Nd2O3 lattice. Analyses of transmission electron microscopy (TEM) and Raman spectroscopy of NNO recorded at room temperature (RT) also substantiate this fact. Besides, no traces of impurities are found in the analyses of XRD, TEM and Raman data. Room temperature hysteresis loop of NNO suggests the presence of weak ferromagnetism (FM) in low field region ( 600 mT), but in high field region paramagnetism of the host is more prominent. Magnetization vs. temperature ( M- T) curve in the entire temperature range (300-5 K) is analyzed successfully by a combined equation generated from three-dimensional (3D) spin wave model and Curie-Weiss law, which suggests the presence of mixed paramagnetic phase together with ferromagnetic phase in the doped sample. The onset of magnetic ordering is analyzed by oxygen vacancy mediated F-center exchange (FCE) coupling mechanism.

Development of quantitative analysis for cadmium, lead and chromium in aluminum alloys by using x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Yamashita, Satoshi; Kurusu, Kazuhiko; Kudou, Aiko

2009-01-01

A highly reliable quantitative analysis for cadmium, lead and chromium in aluminum alloys was developed. Standard samples were made by doping cadmium, lead and chromium into several aluminum alloys, and the composition of standard samples were determined by inductively coupled plasma optical emission spectrometry and gravimetric method. The calibration curves for these standard samples by using WD-XRF and ED-XRF exhibited linear correlation. Slope of calibration curves for Al-Cu alloy and Al-Zn-Mg alloy were smaller than other alloy's one, because of the effect by coexistent elements. Then, all calibration curves agreed with each other by performing correction with α-coefficient method. (author)

Thermoluminescence properties of undoped and Tb3+ and Ce3+ doped YAG nanophosphor under UV-, X- and β-ray irradiation

International Nuclear Information System (INIS)

Rosa, E. de la; Rodriguez, R.A.; Melendrez, R.; Salas, P.; Diaz-Torres, L.A.; Barboza-Flores, M.

2007-01-01

The thermoluminescence (TL) properties of undoped, Ce 3+ and Tb 3+ doped Y 3 Al 5 O 12 (YAG) nanocrystals under UV-, X- and β-rays irradiation is reported. The TL signal of undoped and doped samples indicates a high sensitivity to UV-, X- and β-ray irradiation. The introduction of the doping ions induces changes in the trapping processes and the TL efficiency. The results show that both undoped and doped YAG nanocrystalline phosphor present good TL efficiency as well as good dose response which qualify them as a potential UV-, X- and β-ray dosimeter. A linear response under X-ray irradiation is observed for low doses level in the 0.02-1.02 μGy range and for relatively high doses level of β-ray irradiation in the range from 10 to 600 Gy

Improvement of cadmium phytoremediation after soil inoculation with a cadmium-resistant Micrococcus sp.

Science.gov (United States)

Sangthong, Chirawee; Setkit, Kunchaya; Prapagdee, Benjaphorn

2016-01-01

Cadmium-resistant Micrococcus sp. TISTR2221, a plant growth-promoting bacterium, has stimulatory effects on the root lengths of Zea mays L. seedlings under toxic cadmium conditions compared to uninoculated seedlings. The performance of Micrococcus sp. TISTR2221 on promoting growth and cadmium accumulation in Z. mays L. was investigated in a pot experiment. The results indicated that Micrococcus sp. TISTR2221significantly promoted the root length, shoot length, and dry biomass of Z. mays L. transplanted in both uncontaminated and cadmium-contaminated soils. Micrococcus sp. TISTR2221 significantly increased cadmium accumulation in the roots and shoots of Z. mays L. compared to uninoculated plants. At the beginning of the planting period, cadmium accumulated mainly in the shoots. With a prolonged duration of cultivation, cadmium content increased in the roots. As expected, little cadmium was found in maize grains. Soil cadmium was significantly reduced with time, and the highest percentage of cadmium removal was found in the bacterial-inoculated Z. mays L. after transplantation for 6 weeks. We conclude that Micrococcus sp. TISTR2221 is a potent bioaugmenting agent, facilitating cadmium phytoextraction in Z. mays L.

Biofabrication of morphology improved cadmium sulfide nanoparticles using Shewanella oneidensis bacterial cells and ionic liquid: For toxicity against brain cancer cell lines.

Science.gov (United States)

Wang, Li; Chen, Siyuan; Ding, Yiming; Zhu, Qiang; Zhang, Nijia; Yu, Shuqing

2018-01-01

The present work determines the anticancer activity of bio-mediated synthesized cadmium sulfide nanoparticles using the ionic liquid and bacterial cells (Shewanella oneidensis). Bacterial cells have been exposed to be important resources that hold huge potential as ecofriendly, cost-effective, evading toxic of dangerous chemicals and the alternative of conventional physiochemical synthesis. The Shewanella oneidensis is an important kind of metal reducing bacterium, known as its special anaerobic respiratory and sulfate reducing capacity. The crystalline nature, phase purity and surface morphology of biosynthesized cadmium sulfide nanoparticles were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive spectroscopy and Transmission electron microscopy. The use of imidazolium based ionic liquids as soft templating agent for controlling self-assembly and crystal growth direction of metal sulfide nanoparticles has also advanced as an important method. The microscopic techniques showed that the nanoparticles are designed on the nano form and have an excellent spherical morphology, due to the self-assembled mechanism of ionic liquid assistance. The antitumor efficiency of the cadmium sulfide nanoparticles was investigated against brain cancer cell lines using rat glioma cell lines. The effectively improved nano-crystalline and morphological structure of CdS nanoparticles in the presence of IL exhibit excellent cytotoxicity and dispersion ability on the cell shape is completely spread out showing a nice toxic environment against cancer cells. The cytotoxicity effect of cadmium sulfide nanoparticles was discussed with a diagrammatic representation. Copyright © 2017. Published by Elsevier B.V.

Cadmium accumulation by Axonopus compressus (Sw.) P. Beauv and Cyperus rotundas Linn growing in cadmium solution and cadmium-zinc contaminated soil

OpenAIRE

Paitip Thiravetyan; Vibol Sao; Woranan Nakbanpote

2007-01-01

This research investigated the phyto-remediation potentials of Cyperus rotundas Linn (Nutgrass) and Axonopus compressus (Sw.) P. Beauv (Carpetgrass) for cadmium removal from cadmium solution andcadmium-zinc contaminated soil. Plants growth in the solution showed that cadmium decreased the relative growth rate of both grasses. However, the amount of cadmium accumulated in shoot and root was increasedwith the increase in cadmium concentration and exposure time. Growth in fertile soil mixed with...

Nanocrystalline permanent magnets with enhanced properties

International Nuclear Information System (INIS)

Leonowicz, M.

2002-01-01

Parameters of permanent magnets result from the combination of intrinsic properties such as saturation magnetization, magnetic exchange, and magnetocrystalline energy, as well as microstructural parameters such as phase structure, grain size, and orientation. Reduction of grain size into nanocrystalline regime (∼ 50 nm) leads to the enhanced remanence which derives from ferromagnetic exchange coupling between highly refined grains. In this study the fundamental phenomena, quantities, and structure parameters, which define nanophase permanent magnets are presented and discussed. The theoretical considerations are confronted with experimental data for nanocrystalline Sm-Fe-N type permanent magnets. (author)

Nanodiamond Films for Applications in Electrochemical Systems

Directory of Open Access Journals (Sweden)

A. F. Azevedo

2012-01-01

Full Text Available The purpose of the present paper is to give an overview on the current development status of nanocrystalline diamond electrodes for electrochemical applications. Firstly, we describe a brief comparison between the general properties of nanocrystalline diamond (undoped and boron-doped and boron-doped microcrystalline diamond films. This is followed by a summary of the nanodiamond preparation methods. Finally, we present a discussion about the undoped and boron-doped nanocrystalline diamond and their characteristics, electrochemical properties, and practical applications.

Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

Czech Academy of Sciences Publication Activity Database

Nesládek, M.; Mareš, Jiří J.; Tromson, D.; Mer, Ch.; Bergonzo, P.; Hubík, Pavel; Krištofik, Jozef

2006-01-01

Roč. 7, Suppl. 1 (2006), S41-S44 ISSN 1468-6996 R&D Projects: GA ČR(CZ) GA202/06/0040 Institutional research plan: CEZ:AV0Z10100521 Keywords : superconductivity * electrical transport * doping * CVD diamond Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2006

Structural morphology, upconversion luminescence and optical thermometric sensing behavior of Y2O3:Er(3+)/Yb(3+) nano-crystalline phosphor.

Science.gov (United States)

Joshi, C; Dwivedi, A; Rai, S B

2014-08-14

Infrared-to-visible upconverting rare earths Er(3+)/Yb(3+) co-doped Y2O3 nano-crystalline phosphor samples have been prepared by solution combustion method followed by post-heat treatment at higher temperatures. A slight increase in average crystallite size has been found on calcinations verified by X-ray analysis. Transmission electron microscopy (TEM) confirms the nano-crystalline nature of the as-prepared and calcinated samples. Fourier transform infrared (FTIR) analysis shows the structural changes in as-prepared and calcinated samples. Upconversion and downconversion emission recorded using 976 and 532 nm laser sources clearly demonstrates a better luminescence properties in the calcinated samples as compared to as-prepared sample. Upconversion emission has been quantified in terms of standard chromaticity diagram (CIE) showing a shift in overall upconversion emission of as-prepared and calcinated samples. Temperature sensing behaviour of this material has also been investigated by measurement of fluorescence intensity ratio (FIR) of various signals in green emission in the temperature range of 315 to 555 K under 976 nm laser excitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Thermodynamic and experimental study on phase stability in nanocrystalline alloys

International Nuclear Information System (INIS)

Xu Wenwu; Song Xiaoyan; Lu Nianduan; Huang Chuan

2010-01-01

Nanocrystalline alloys exhibit apparently different phase transformation characteristics in comparison to the conventional polycrystalline alloys. The special phase stability and phase transformation behavior, as well as the essential mechanisms of the nanocrystalline alloys, were described quantitatively in a nanothermodynamic point of view. By introducing the relationship between the excess volume at the grain boundary and the nanograin size, the Gibbs free energy was determined distinctly as a function of temperature and the nanograin size. Accordingly, the grain-size-dependence of the phase stability and phase transformation characteristics of the nanocrystalline alloy were calculated systematically, and the correlations between the phase constitution, the phase transformation temperature and the critical nanograin size were predicted. A series of experiments was performed to investigate the phase transformations at room temperature and high temperatures using the nanocrystalline Sm 2 Co 17 alloy as an example. The phase constitution and phase transformation sequence found in nanocrystalline Sm 2 Co 17 alloys with various grain-size levels agree well with the calculations by the nanothermodynamic model.

Cadmium accumulation by Axonopus compressus (Sw. P. Beauv and Cyperus rotundas Linn growing in cadmium solution and cadmium-zinc contaminated soil

Directory of Open Access Journals (Sweden)

Paitip Thiravetyan

2007-05-01

Full Text Available This research investigated the phyto-remediation potentials of Cyperus rotundas Linn (Nutgrass and Axonopus compressus (Sw. P. Beauv (Carpetgrass for cadmium removal from cadmium solution andcadmium-zinc contaminated soil. Plants growth in the solution showed that cadmium decreased the relative growth rate of both grasses. However, the amount of cadmium accumulated in shoot and root was increasedwith the increase in cadmium concentration and exposure time. Growth in fertile soil mixed with Cd-contaminated zinc silicate residue (65% Si, 19% Ca, 2% Zn, 1% Mg and 0.03% Cd at the ratio of 50:50 (w/wfor 30 days showed that C. rotundas Linn accumulated cadmium in root and shoot to 2,178 and 1,144 mg kg-1 dry weight, respectively. A. compressus (Sw. P. Beauv accumulated cadmium in root and shoot to 1,965and 669 mg kg-1 dry weight, respectively. Scanning electron microscope connected to energy-dispersive X-ray spectroscopy suggested that the mechanism of cadmium accumulation by both grasses involved thecadmium precipitation in the stable form of cadmium silicate, which indicated that C. rotundas Linn and A. compressus (Sw. P. Beauv could be grown to prevent soil erosion and to remediate cadmium-contaminatedsoil.

Cadmium, an environmental poison

Energy Technology Data Exchange (ETDEWEB)

Oestergaard, A K

1974-04-15

In recent years, industrial employment of cadmium has increased considerably. Cadmium is now present in the environment and has caused acute and chronic poisoning. Inhalation of cadmium vapor or dust causes pulmonary damage while the kidney is the critical organ in absorption of cadmium. The element accumulates in the kidney and causes tubular damage or 200 ppm in the renal cortex. In animal experiments, cadmium may cause raised blood pressure, sterility and malignant tumors. On account of the pronounced tendency of cadmium to accumulate and its toxicity, it is important to trace sources and to reduce exposure of the population. 62 references.

Tailoring and patterning the grain size of nanocrystalline alloys

International Nuclear Information System (INIS)

Detor, Andrew J.; Schuh, Christopher A.

2007-01-01

Nanocrystalline alloys that exhibit grain boundary segregation can access thermodynamically stable or metastable states with the average grain size dictated by the alloying addition. Here we consider nanocrystalline Ni-W alloys and demonstrate that the W content controls the grain size over a very broad range: ∼2-140 nm as compared with ∼2-20 nm in previous work on strongly segregating systems. This trend is attributed to a relatively weak tendency for W segregation to the grain boundaries. Based upon this observation, we introduce a new synthesis technique allowing for precise composition control during the electrodeposition of Ni-W alloys, which, in turn, leads to precise control of the nanocrystalline grain size. This technique offers new possibilities for understanding the structure-property relationships of nanocrystalline solids, such as the breakdown of Hall-Petch strength scaling, and also opens the door to a new class of customizable materials incorporating patterned nanostructures

Protein-modified nanocrystalline diamond thin films for biosensor applications.

Science.gov (United States)

Härtl, Andreas; Schmich, Evelyn; Garrido, Jose A; Hernando, Jorge; Catharino, Silvia C R; Walter, Stefan; Feulner, Peter; Kromka, Alexander; Steinmüller, Doris; Stutzmann, Martin

2004-10-01

Diamond exhibits several special properties, for example good biocompatibility and a large electrochemical potential window, that make it particularly suitable for biofunctionalization and biosensing. Here we show that proteins can be attached covalently to nanocrystalline diamond thin films. Moreover, we show that, although the biomolecules are immobilized at the surface, they are still fully functional and active. Hydrogen-terminated nanocrystalline diamond films were modified by using a photochemical process to generate a surface layer of amino groups, to which proteins were covalently attached. We used green fluorescent protein to reveal the successful coupling directly. After functionalization of nanocrystalline diamond electrodes with the enzyme catalase, a direct electron transfer between the enzyme's redox centre and the diamond electrode was detected. Moreover, the modified electrode was found to be sensitive to hydrogen peroxide. Because of its dual role as a substrate for biofunctionalization and as an electrode, nanocrystalline diamond is a very promising candidate for future biosensor applications.

Cadmium and the kidney.

OpenAIRE

Friberg, L

1984-01-01

The paper is a review of certain aspects of importance of cadmium and the kidney regarding the assessment of risks and understanding of mechanisms of action. The review discusses the following topics: history and etiology of cadmium-induced kidney dysfunction and related disorders; cadmium metabolism, metallothionein and kidney dysfunction; cadmium in urine as indicator of body burden, exposure and kidney dysfunction; cadmium levels in kidney and liver as indicators of kidney dysfunction; cha...

Cadmium

NARCIS (Netherlands)

Meulenbelt, Jan

2017-01-01

Together with zinc and mercury, cadmium belongs to group IIb of the periodic table. It can be found in rocks, soil, water, coal, zinc ore, lead ore, and copper ore. In the environment, cadmium is present predominantly as the oxide or as the chloride, sulfide, or sulfate salt. It has no recognizable

In vitro corrosion, cytotoxicity and hemocompatibility of bulk nanocrystalline pure iron

International Nuclear Information System (INIS)

Nie, F L; Zheng, Y F; Wei, S C; Hu, C; Yang, G

2010-01-01

Bulk nanocrystalline pure iron rods were fabricated by the equal channel angular pressure (ECAP) technique up to eight passes. The microstructure and grain size distribution, natural immersion and electrochemical corrosion in simulated body fluid, cellular responses and hemocompatibility were investigated in this study. The results indicate that nanocrystalline pure iron after severe plastic deformation (SPD) would sustain durable span duration and exhibit much stronger corrosion resistance than that of the microcrystalline pure iron. The interaction of different cell lines reveals that the nanocrystalline pure iron stimulates better proliferation of fibroblast cells and preferable promotion of endothelialization, while inhibits effectively the viability of vascular smooth muscle cells (VSMCs). The burst of red cells and adhesion of the platelets were also substantially suppressed on contact with the nanocrystalline pure iron in blood circulation. A clear size-dependent behavior from the grain nature deduced by the gradual refinement microstructures was given and well-behaved in vitro biocompatibility of nanocrystalline pure iron was concluded.

Magnetic properties of nanocrystalline pyrrhotite prepared by high-energy milling

DEFF Research Database (Denmark)

Balaz, P.; Godocikova, E.; Alacova, A.

2004-01-01

The nanocrystalline pyrrhotite was prepared by high-energy milling of lead sulphide with elemental Fe acting as reducing element. X-ray diffractometry, Mossbauer spectroscopy and VSM magnetometry were used to determine the properties of nanocrystalline iron sulphide prepared by the corresponding...... mechanochemical reaction. Pyrrhotite Fe1-xS together with the residual Fe metal were identified by the X-ray diffractometry. The kinetic studies performed by Mossbauer spectroscopy and VSM magnetometry allowed us to follow in more details the progress of the nanocrystalline magnetic phase formation during...

Theoretical study on recoilless fractions of simple cubic monatomic nanocrystalline particles

International Nuclear Information System (INIS)

Huang Jianping; Wang Luya

2002-01-01

Recoilless fractions of simple cubic monatomic nanocrystalline particles are calculated by using displacement-displacement Green's function. The numerical results show that the recoilless fractions on the surface of monatomic nanocrystalline particles are smaller than those in the inner, and they decrease when the particle size increase, the recoilless fractions of whole monatomic nanocrystalline particles increase when the particle size increase. These effects are more evident when the temperature is higher

Effect of Li2O-doping of nanocrystalline CoO/Fe2O3 on isopropanol conversion

International Nuclear Information System (INIS)

El-Shobaky, Hala G.; Ali, Suzan A.H.; Hassan, Neven A.

2007-01-01

The catalytic conversion of isopropanol was carried out over pure and Li 2 O-doped (0.75-4.5 mol%) cobalt ferrite prepared by heating Fe/Co mixed hydroxides at 400 and 600 deg. C. The techniques employed were XRD, N 2 adsorption at -196 deg. C and conversion of isopropanol at 200-400 deg. C using a flow method. The results showed that Li 2 O-doping and increasing the heating temperature of the system investigated from 400 to 600 deg. C stimulated CoFe 2 O 4 formation also. Pure and variously doped solids were moderately crystallized CoFe 2 O 4 phase having a crystallite size varying between 5 and 15 nm. The S BET of various solids was found to decrease by increasing their calcination temperature and also by doping with 4.5 mol% Li 2 O. However, this treatment, resulted in a significant increase in their catalytic activities which much increased by doping. The presence of 1.5 mol% Li 2 O brought about an increase in the catalytic activity, measured at 300 deg. C, of 97% and 63% for the solids being calcined at 400 and 600 deg. C, respectively. All solids investigated behaved as dehydrogenation catalysts (having selectivities to acetone formation above 95%). The doping process did not alter the mechanism of dehydrogenation of isopropanol, but increased the concentration of active sites involved in the catalyzed reaction

Preparation, structural and luminescent properties of nanocrystalline ZnO films doped Ag by close space sublimation method

Science.gov (United States)

Khomchenko, Viktoriya; Mazin, Mikhail; Sopinskyy, Mykola; Lytvyn, Oksana; Dan'ko, Viktor; Piryatinskii, Yurii; Demydiuk, Pavlo

2018-05-01

The simple way for silver doping of ZnO films is presented. The ZnO films were prepared by reactive rf-magnetron sputtering on silicon and sapphire substrates. Ag doping is carried out by sublimation of the Ag source located at close space at atmospheric pressure in air. Then the ZnO and ZnO-Ag films were annealed in wet media. The microstructure and optical properties of the films were compared and studied by atomic force microscopy (AFM), X-ray diffraction (XRD), photoluminescence (PL) and cathodoluminescence (CL). XRD results indicated that all the ZnO films have a polycrystalline hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. The annealing and Ag doping promote increasing grain's sizes and modification of grain size distribution. The effect of substrate temperature, substrate type, Ag doping and post-growth annealing of the films was studied by PL spectroscopy. The effect of Ag doping was obvious and identical for all the films, namely the wide visible bands of PL spectra are suppressed by Ag doping. The intensity of ultraviolet band increased 15 times as compared to their reference films on sapphire substrate. The ultraviolet/visible emission ratio was 20. The full width at half maximum (FWHM) for a 380 nm band was 14 nm, which is comparable with that of epitaxial ZnO. The data implies the high quality of ZnO-Ag films. Possible mechanisms to enhance UV emission are discussed.

Ni-doped (CeO2−δ)–YSZ mesoarchitectured with nanocrystalline framework: the effect of thermal treatment on structure, surface chemistry and catalytic properties in the partial oxidation of methane (CPOM)

International Nuclear Information System (INIS)

Somacescu, Simona; Florea, Mihaela; Osiceanu, Petre; Calderon-Moreno, Jose Maria; Ghica, Corneliu; Serra, Jose Manuel

2015-01-01

Ni-doped (CeO 2−δ )–YSZ (5 mol% Ni oxide, 10 mol% ceria) mesoarchitectures (MA) with nanocrystalline framework have been synthesized by an original, facile and cheap approach based on Triton X100 nonionic surfactant as template and water as solvent at a strong basic pH value. Following the hydrothermal treatment under autogenous pressure (∼18 bars), Ni, Ce, Y, and Zr were well ordered as MA with nanocrystalline framework, assuring thermal stability. A comprehensive investigation of structure, texture, morphology, and surface chemistry was performed by means of a variety of complementary techniques (X-Ray Diffraction, XRD; Raman Spectroscopy, RS; Brunauer—Emmett—Teller, BET; Temperature—Programmed Reduction, TPR; Transmission Electron Microscopy, TEM and DF-STEM; X-ray Photoelectron Spectroscopy, XPS; Catalytic activity and selectivity). N 2 sorption measurements highlighted that the mesoporous structure is formed at 600 °C and remains stable at 800 °C. At 900 °C, the MA collapses, favoring the formation of macropores. The XRD and Raman Spectroscopy of all samples showed the presence of a pure, single phase with fluorite-type structure. At 900 °C, an increased tetragonal distortion of the cubic lattice was observed. The surface chemistry probed by XPS exhibits a mixture of oxidation states (Ce 3+  + Ce 4+ ) with high percentage of Ce 3+ valence state ∼35 % and (Ni 3+ and Ni 2+ ) oxidation states induced by the thermal treatment. These nanoparticles assembled into MA show high stability and selectivity over time in catalytic partial oxidation of methane (CPOM). These promising performances suggest an interesting prospect for introduction as anode within IT-SOFC assemblies.Graphical Abstract

Thermoluminescent properties of ZnS:Mn nanocrystalline powders

International Nuclear Information System (INIS)

Ortiz-Hernández, Arturo Agustín; Méndez García, Víctor Hugo; Pérez Arrieta, María Leticia; Ortega Sígala, José Juan

2015-01-01

Thermoluminescent ZnS nanocrystals doped with Mn 2+ ions were synthesized by chemical co-precipitation method. From X-ray diffraction studies it was observed that the synthesized nanoparticles have cubic zinc blende structure with average sizes of about 40–50 nm. Morphology was analyzed by TEM. Photoluminescence studies showed two transitions, one of them close to 396 nm and other close to 598 nm, which is enhanced with increasing dopant concentration, this behavior was also observed in the cathodoluminescence spectrum. The thermoluminescence gamma dose-response has linear behavior over dose range 5–100 mGy, the glow curve structure shows two glow peaks at 436 K and at 518 K that were taken into account to calculate the kinetic parameters using the Computerized Glow Curve Deconvolution procedure. - Highlights: • Nanocrystals in powder of ZnS:Mn were synthesized using the co-precipitation method. • The integrated TL spectra has a linear behavior on the dose range 5–100 mGy of γ-radiation. • The kinetic parameters were obtained by the CGCD procedure. • Results support the possible use of nanocrystalline ZnS:Mn as a new γ-dose nanoTLD

Ultra-nanocrystalline diamond nanowires with enhanced electrochemical properties

International Nuclear Information System (INIS)

Shalini, Jayakumar; Lin, Yi-Chieh; Chang, Ting-Hsun; Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Lin, I.-Nan; Lee, Chi-Young; Tai, Nyan-Hwa

2013-01-01

The effects of N 2 incorporation in Ar/CH 4 plasma on the electrochemical properties and microstructure of ultra-nanocrystalline diamond (UNCD) films are reported. While the electrical conductivity of the films increased monotonously with increasing N 2 content (up to 25%) in the plasma, the electrochemical behavior was optimized for UNCD films grown in (Ar–10% N 2 )/CH 4 plasma. Transmission electron microscopy showed that the main factor resulting in high conductivity in the films was the formation of needle-like nanodiamond grains and the induction graphite layer encapsulating these grains. The electrochemical process for N 2 -incorporated UNCD films can readily be activated due to the presence of nanographite along the grain boundaries of the films. The formation of needle-like diamond grains was presumably due to the presence of CN species that adhered to the existing nanodiamond clusters, which suppressed radial growth of the nanodiamond crystals, promoting anisotropic growth and the formation of needle-like nanodiamond. The N 2 -incorporated UNCD films outperformed other electrochemical electrode materials, such as boron-doped diamond and glassy carbon, in that the UNCD electrodes could sense dopamine, urea, and ascorbic acid simultaneously in the same mixture with clear resolution

Flux of Cadmium through Euphausiids

International Nuclear Information System (INIS)

Benayoun, G.; Fowler, S.W.; Oregioni, B.

1976-01-01

Flux of the heavy metal cadmium through the euphausiid Meganyctiphanes norvegica was examined. Radiotracer experiments showed that cadmium can be accumulated either directly from water or through the food chain. When comparing equilibrium cadmium concentration factors based on stable element measurements with those obtained from radiotracer experiments, it is evident that exchange between cadmium in the water and that in euphausiid tissue is a relatively slow process, indicating that, in the long term, ingestion of cadmium will probably be the more important route for the accumulation of this metal. Approximately 10% of cadmium ingested by euphausiids was incorporated into internal tissues when the food source was radioactive Artemia. After 1 month cadmium, accumulated directly from water, was found to be most concentrated in the viscera with lesser amounts in eyes, exoskeleton and muscle, respectively. Use of a simple model, based on the assumption that cadmium taken in by the organism must equal cadmium released plus that accumulated in tissue, allowed assessment of the relative importance of various metabolic parameters in controlling the cadmium flux through euphausiids. Fecal pellets, due to their relatively high rate of production and high cadmium content, accounted for 84% of the total cadmium flux through M. norvegica. Comparisons of stable cadmium concentrations in natural euphausiid food and the organism's resultant fecal pellets indicate that the cadmium concentration in ingested material was increased nearly 5-fold during its passage through the euphausiid. From comparisons of all routes by which cadmium can be released from M. norvegica to the water column, it is concluded that fecal pellet deposition represents the principal mechanism effecting the downward vertical transport of cadmium by this species. (author)

Preparation of Fluorine-Doped TiO2 Photocatalysts with Controlled Crystalline Structure

Directory of Open Access Journals (Sweden)

N. Todorova

2008-01-01

Full Text Available Nanocrystalline F-doped TiO2 powders were prepared by sol-gel route. The thermal behavior of the powders was recorded by DTA/TG technique. The crystalline phase of the fluorinated TiO2 powders was determined by X-ray diffraction technique. It was demonstrated that F-doping using CF3COOH favors the formation of rutile along with anatase phase even at low temperature. Moreover, the rutile's phase content increases with the increase of the quantity of the fluorine precursor in the starting solution. The surface area of the powders and the pore size distribution were studied by N2 adsorption-desorption using BET and BJH methods. X-ray photoelectron spectroscopy (XPS revealed that the fluorine is presented in the TiO2 powders mainly as metal fluoride in quantities ∼16 at %. The F-doped TiO2 showed a red-shift absorption in UV-vis region which was attributed to the increased content of rutile phase in the powders. The powders exhibited enhanced photocatalytic activity in decomposition of acetone.

Synthesis of nanocrystalline fluorinated hydroxyapatite

Indian Academy of Sciences (India)

Fluorinated hydroxyapatite; nanocrystalline; microwave synthesis; dissolution. ... HA by the presence of other ions such as carbonate, magnesium, fluoride, etc. ... Fourier transform infrared spectroscopy (FT–IR) and laser Raman spectroscopy.

FEM numerical analysis of excimer laser induced modification in alternating multi-layers of amorphous and nano-crystalline silicon films

Energy Technology Data Exchange (ETDEWEB)

Conde, J.C., E-mail: jconde@uvigo.es [Dpto. Fisica Aplicada, Universidade de Vigo, Rua Maxwell s/n, Campus Universitario Lagoas Marcosende, Vigo (Spain); Martin, E. [Dpto. Mecanica, Maquinas, Motores Termicos y Fluidos, Universidade de Vigo, Rua Maxwell s/n, Campus Universitario Lagoas Marcosende, Vigo (Spain); Stefanov, S. [Dpto. Fisica Aplicada, Universidade de Vigo, Rua Maxwell s/n, Campus Universitario Lagoas Marcosende, Vigo (Spain); Alpuim, P. [Departamento de Fisica, Universidade do Minho, 4800-058 Guimaraes (Portugal); Chiussi, S. [Dpto. Fisica Aplicada, Universidade de Vigo, Rua Maxwell s/n, Campus Universitario Lagoas Marcosende, Vigo (Spain)

2012-09-15

Highlights: Black-Right-Pointing-Pointer nc-Si:H is a material with growing importance for a large-area of nano-electronic, photovoltaic or biomedical devices. Black-Right-Pointing-Pointer UV-ELA technique causes a rapid heating that provokes the H{sub 2} desorption from the Si surface and bulk material. Black-Right-Pointing-Pointer Next, diffusion of P doped nc-Si films and eventually, for high energy densities would be possible to reach the melting point. Black-Right-Pointing-Pointer These multilayer structures consisting of thin alternating a-Si:H(10 nm) and n-doped nc-Si:H(60 nm) films deposited on SiO{sub 2}. Black-Right-Pointing-Pointer To optimize parameters involved in this processing, FEM numerical analysis of multilayer structures have been performed. Black-Right-Pointing-Pointer The numerical results are compared with exhaustive characterization of the experimental results. - Abstract: UV excimer laser annealing (UV-ELA) is an alternative annealing process that, during the last few years, has gained enormous importance for the CMOS nano-electronic technologies, with the ability to provide films and alloys with electrical and optical properties to fit the desired device performance. The UV-ELA of amorphous (a-) and/or doped nano-crystalline (nc-) silicon films is based on the rapid (nanoseconds) formation of temperature profiles caused by laser radiation that is absorbed in the material and lead to crystallisation, diffusion in solid or even in liquid phase. To achieve the desired temperature profiles and to optimize the parameters involved in the processing of hydrogenated nanocrystalline silicon (nc-Si:H) films with the UV-ELA, a numerical analysis by finite element method (FEM) of a multilayer structure has been performed. The multilayer structures, consisting of thin alternating a-Si:H(10 nm) and n-doped nc-Si:H(60 nm) layers, deposited on a glass substrate, has also been experimentally analyzed. Temperature profiles caused by 193 nm radiation with 25

Synthesis of nanocrystalline LaF3 doped silica glasses by hydrofluoric acid catalyzed sol–gel process

International Nuclear Information System (INIS)

Nagayama, Shuhei; Kajihara, Koichi; Kanamura, Kiyoshi

2012-01-01

Highlights: ► Silica glasses doped by LaF 3 nanocrystals are obtained by HF-catalyzed sol–gel method. ► The processing time (∼1 week) is much shorter than that of previous studies. ► The uptake of SiF groups in the glass matrix greatly reduces the SiOH concentration. ► Effects of sintering conditions and properties of Er 3+ -doped samples are presented. - Abstract: Silica glasses doped with LaF 3 nanocrystals were prepared by HF-catalyzed sol–gel method. HF was used both as fluorine source and as catalyst of the sol–gel reaction, making it possible to shorten the processing time with reducing the concentration of SiOH groups to ∼10 18 cm −3 . The resultant glasses are transparent at visible spectral range, and the optical loss at the ultraviolet absorption edge is dominated by the Rayleigh scattering from LaF 3 crystallites. The size of LaF 3 crystallites increases with an increase in the sintering temperature and time, and is smaller than ∼40 nm in samples showing good visible transparency. Green upconversion photoluminescence is observed in an Er 3+ -doped sample under excitation at 980 nm.

Calcium enhances cadmium tolerance and decreases cadmium ...

African Journals Online (AJOL)

We aimed at characterizing mechanisms controlling cadmium accumulation in lettuce, which is a food crop showing one of the highest capacities to accumulate this toxic compound. In this study, plants from three lettuce varieties were grown for eight days on media supplemented or not with cadmium (15 μM CdCl2) and ...

Magnetic and dielectric study of Fe-doped CdSe nanoparticles

Science.gov (United States)

Das, Sayantani; Banerjee, Sourish; Bandyopadhyay, Sudipta; Sinha, Tripurari Prasad

2018-01-01

Nanoparticles of cadmium selenide (CdSe) and Fe (5% and 10%) doped CdSe have been synthesized by soft chemical route and found to have cubic structure. The magnetic field dependent magnetization measurement of the doped samples indicates the presence of anti-ferromagnetic order. The temperature dependent magnetization (M-T) measurement under zero field cooled and field cooled conditions has also ruled out the presence of ferromagnetic component in the samples at room temperature as well as low temperature. In order to estimate the anti-ferromagnetic coupling among the doped Fe atoms, an M-T measurement at 500 Oe has been carried out, and the Curie-Weiss temperature θ of the samples has been estimated from the inverse of susceptibility versus temperature plots. The dielectric relaxation peaks are observed in the spectra of imaginary part of dielectric constant. The temperature dependent relaxation time is found to obey the Arrhenius law having activation energy 0.4 eV for Fe doped samples. The frequency dependent conductivity spectra are found to obey the power law. [Figure not available: see fulltext.

A facile and fast approach for the synthesis of doped nanoparticles using a microfluidic device

International Nuclear Information System (INIS)

Singh, Akanksha; Limaye, Mukta; Singh, Shashi; Kulkarni, Sulabha; Lalla, Niranjan Prasad; Malek, Chantal Khan

2008-01-01

The microfluidic approach emerges as a new and promising technology for the synthesis of nanomaterials. A microreactor allows a variety of reaction conditions to be quickly scanned without consuming large amounts of raw material. In this study, we investigated the synthesis of water soluble 1-thioglycerol-capped Mn-doped ZnS nanocrystalline semiconductor nanoparticles (TG-capped ZnS:Mn) via a microfluidic approach. This is the first report for the successful doping of Mn in a ZnS semiconductor at room temperature as well as at 80 deg. C using a microreactor. Transmission electron microscopy and x-ray diffraction analysis show that the average particle size of Mn-doped ZnS nanoparticles is ∼3.0 nm with a zinc-blende structure. Photoluminescence, x-ray photoelectron spectroscopy, atomic absorption spectroscopy and electron paramagnetic resonance studies were carried out to confirm that the Mn 2+ dopants are present in the ZnS nanoparticles

Size-mediated cytotoxicity of nanocrystalline titanium dioxide, pure and zinc-doped hydroxyapatite nanoparticles in human hepatoma cells

International Nuclear Information System (INIS)

Devanand Venkatasubbu, G.; Ramasamy, S.; Avadhani, G. S.; Palanikumar, L.; Kumar, J.

2012-01-01

Nanoparticles are highly used in biological applications including nanomedicine. In this present study, the interaction of HepG2 hepatocellular carcinoma cells (HCC) with hydroxyapatite (HAp), zinc-doped hydroxyapatite, and titanium dioxide (TiO 2 ) nanoparticles were investigated. Hydroxyapatite, zinc-doped hydroxyapatite and titanium dioxide nanoparticles were prepared by wet precipitation method. They were subjected to isochronal annealing at different temperatures. Particle morphology and size distribution were characterized by X-ray diffraction and transmission electron microscope. The nanoparticles were co-cultured with HepG2 cells. MTT assay was employed to evaluate the proliferation of tumor cells. The DNA damaging effect of HAp, Zn-doped HAp, and TiO 2 nanoparticles in human hepatoma cells (HepG2) were evaluated using DNA fragmentation studies. The results showed that in HepG2 cells, the anti-tumor activity strongly depend on the size of nanoparticles in HCC cells. Cell cycle arrest analysis for HAp, zinc-doped HAp, and TiO 2 nanoparticles revealed the influence of HAp, zinc-doped HAp, and titanium dioxide nanoparticles on the apoptosis of HepG2 cells. The results imply that the novel nano nature effect plays an important role in the biomedicinal application of nanoparticles.

Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis

International Nuclear Information System (INIS)

Hartner, Sonja; Schulz, Christof; Wiggers, Hartmut; Ali, Moazzam; Winterer, Markus

2009-01-01

Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis.

Science.gov (United States)

Hartner, Sonja; Ali, Moazzam; Schulz, Christof; Winterer, Markus; Wiggers, Hartmut

2009-11-04

Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

Effect of Low Concentration Sn Doping on Optical Properties of CdS Films Grown by CBD Technique

Directory of Open Access Journals (Sweden)

Mohd Sabri Mohd Ghazali

2011-09-01

Full Text Available Thin and transparent films of doped cadmium sulfide (CdS were obtained on commercial glass substrates by Chemical Bath Deposition (CBD technique. The films were doped with low concentration of Sn, and annealed in air at 300 °C for 45 min. The morphological characterization of the films with different amounts of dopant was made using SEM and EDAX analysis. Optical properties of the films were evaluated by measuring transmittance using the UV-vis spectrophotometer. A comparison of the results revealed that lower concentration of Sn doping improves transmittance of CdS films and makes them suitable for application as window layer of CdTe/CIGS solar cells.

New route to the fabrication of nanocrystalline diamond films

International Nuclear Information System (INIS)

Varshney, Deepak; Morell, Gerardo; Palomino, Javier; Resto, Oscar; Gil, Jennifer; Weiner, Brad R.

2014-01-01

Nanocrystalline diamond (NCD) thin films offer applications in various fields, but the existing synthetic approaches are cumbersome and destructive. A major breakthrough has been achieved by our group in the direction of a non-destructive, scalable, and economic process of NCD thin-film fabrication. Here, we report a cheap precursor for the growth of nanocrystalline diamond in the form of paraffin wax. We show that NCD thin films can be fabricated on a copper support by using simple, commonplace paraffin wax under reaction conditions of Hot Filament Chemical Vapor Deposition (HFCVD). Surprisingly, even the presence of any catalyst or seeding that has been conventionally used in the state-of-the-art is not required. The structure of the obtained films was analyzed by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy and electron energy-loss spectroscopy recorded at the carbon K-edge region confirm the presence of nanocrystalline diamond. The process is a significant step towards cost-effective and non-cumbersome fabrication of nanocrystalline diamond thin films for commercial production

Ni-doped (CeO{sub 2−δ})–YSZ mesoarchitectured with nanocrystalline framework: the effect of thermal treatment on structure, surface chemistry and catalytic properties in the partial oxidation of methane (CPOM)

Energy Technology Data Exchange (ETDEWEB)

Somacescu, Simona, E-mail: ssimona@icf.ro [Romanian Academy, “Ilie Murgulescu” Institute of Physical Chemistry (Romania); Florea, Mihaela [University of Bucharest, Department of Organic Chemistry, Biochemistry and Catalysis, Faculty of Chemistry (Romania); Osiceanu, Petre; Calderon-Moreno, Jose Maria [Romanian Academy, “Ilie Murgulescu” Institute of Physical Chemistry (Romania); Ghica, Corneliu [National Institute of Materials Physics (Romania); Serra, Jose Manuel [Universidad Politécnica de Valencia - Consejo Superior de Investigaciones Científicas, Instituto de Tecnología Química (Spain)

2015-11-15

Ni-doped (CeO{sub 2−δ})–YSZ (5 mol% Ni oxide, 10 mol% ceria) mesoarchitectures (MA) with nanocrystalline framework have been synthesized by an original, facile and cheap approach based on Triton X100 nonionic surfactant as template and water as solvent at a strong basic pH value. Following the hydrothermal treatment under autogenous pressure (∼18 bars), Ni, Ce, Y, and Zr were well ordered as MA with nanocrystalline framework, assuring thermal stability. A comprehensive investigation of structure, texture, morphology, and surface chemistry was performed by means of a variety of complementary techniques (X-Ray Diffraction, XRD; Raman Spectroscopy, RS; Brunauer—Emmett—Teller, BET; Temperature—Programmed Reduction, TPR; Transmission Electron Microscopy, TEM and DF-STEM; X-ray Photoelectron Spectroscopy, XPS; Catalytic activity and selectivity). N{sub 2} sorption measurements highlighted that the mesoporous structure is formed at 600 °C and remains stable at 800 °C. At 900 °C, the MA collapses, favoring the formation of macropores. The XRD and Raman Spectroscopy of all samples showed the presence of a pure, single phase with fluorite-type structure. At 900 °C, an increased tetragonal distortion of the cubic lattice was observed. The surface chemistry probed by XPS exhibits a mixture of oxidation states (Ce{sup 3+} + Ce{sup 4+}) with high percentage of Ce{sup 3+} valence state ∼35 % and (Ni{sup 3+} and Ni{sup 2+}) oxidation states induced by the thermal treatment. These nanoparticles assembled into MA show high stability and selectivity over time in catalytic partial oxidation of methane (CPOM). These promising performances suggest an interesting prospect for introduction as anode within IT-SOFC assemblies.Graphical Abstract.

Effects of cadmium electrode properties on nickel-cadmium cell performance

International Nuclear Information System (INIS)

Zimmerman, A.H.

1986-01-01

Tests have been conducted on a number of nickel-cadmium cells that have exhibited a variety of performance problems, ranging from high voltages and pressures during overcharge to low capacity. The performance problems that have been specifically linked to the cadmium electrode are primarily related to two areas, poor sinter and the buildup of excessive pressure during overcharge. A number of specific nickel-cadmium cell and cadmium electrode characterists have been studied in this work to determine what the effects of poor sinter are, and to determine what factors are important in causing excessive pressures during overcharge in cells that otherwise appear normal. Several of the tests appear suitable for screening cells and electrodes for such problems

Nanostructured rare earth doped Nb{sub 2}O{sub 5}: Structural, optical properties and their correlation with photonic applications

Energy Technology Data Exchange (ETDEWEB)

Pereira, Rafael Ramiro; Aquino, Felipe Thomaz [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP CEP 14040-901 (Brazil); Ferrier, Alban [PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris (France); Goldner, Philippe [PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France); Gonçalves, Rogéria R., E-mail: rrgoncalves@ffclrp.usp.br [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP CEP 14040-901 (Brazil)

2016-02-15

In the present work, we report on a systematic study on structural and spectroscopic properties Eu{sup 3+} and Er{sup 3+}-doped Nb{sub 2}O{sub 5} prepared by sol–gel method. The Eu{sup 3+} ions were used as structural probe to determine the symmetry sites occupied by lanthanide ions. The Eu{sup 3+}-doped Nb{sub 2}O{sub 5} nanocrystalline powders were annealed at different temperatures to verify how the different Nb{sub 2}O{sub 5} crystalline phases affect the structure and the luminescence properties. Er{sup 3+}-doped Nb{sub 2}O{sub 5} was prepared showing an intense NIR luminescence, and, visible luminescence on the green and red, deriving from upconversion process. The synthetized materials can find widespread applicability in photonics as red luminophor for white LED (with tricolor), optical amplifiers and upconverter materials. - Highlights: • Vis and NIR emission from nanostructured lanthanide doped Nb{sub 2}O{sub 5}. • Eu{sup 3+}-doped Nb{sub 2}O{sub 5} as Red luminophor. • Multicolor tunability of intense upconversion emission from lanthanide doped Nb{sub 2}O{sub 5}. • Potential application as biological markers. • Broad band NIR emission.

Nanocrystalline Al-based alloys - lightweight materials with attractive mechanical properties

International Nuclear Information System (INIS)

Latuch, J; Cieslak, G; Dimitrov, H; Krasnowski, M; Kulik, T

2009-01-01

In this study, several ways of bulk nanocrystalline Al-based alloys' production by high-pressure compaction of powders were explored. The effect of chemical composition and compaction parameters on the structure, quality and mechanical properties of the bulk samples was studied. Bulk nanocrystalline Al-Mm-Ni-(Fe,Co) alloys were prepared by ball-milling of amorphous ribbons followed by consolidation. The maximum microhardness (540 HV0.1) was achieved for the samples compacted at 275 deg. C under 7.7 GPa (which resulted in an amorphous bulk) and nanocrystallised at 235 deg. C for 20 min. Another group of the produced materials were bulk nanocrystalline Al-Si-(Ni,Fe)-Mm alloys obtained by ball-milling of nanocrystalline ribbons and consolidation. The hardness of these samples achieved the value five times higher (350HV) than that of commercial 4xxx series Al alloys. Nanocrystalline Al-based alloys were also prepared by mechanical alloying followed by hot-pressing. In this group of materials, there were Al-Fe alloys containing 50-85 at.% of Al and ternary or quaternary Al-Fe-(Ti, Si, Ni, Mg, B) alloys. Microhardness of these alloys was in the range of 613 - 1235 HV0.2, depending on the composition.

Study of sub band gap absorption of Sn doped CdSe thin films

International Nuclear Information System (INIS)

Kaur, Jagdish; Rani, Mamta; Tripathi, S. K.

2014-01-01

The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively

Study of sub band gap absorption of Sn doped CdSe thin films

Energy Technology Data Exchange (ETDEWEB)

Kaur, Jagdish; Rani, Mamta [Department of Physics, Panjab University, Chandigarh- 160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Panjab University, Chandigarh- 160014 (India)

2014-04-24

The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively.

Photo catalytic degradation of nitrobenzene using nanocrystalline TiO2 photo catalyst doped with Zn ions

International Nuclear Information System (INIS)

Reynoso S, E. A.; Perez S, S.; Reyes C, A. P.; Castro R, C. L.; Felix N, R. M.; Lin H, S. W.; Paraguay D, F.; Alonso N, G.

2013-01-01

Photo catalysis is a method widely used in the degradation of organic pollutants of the environment. The development of new materials is very important to improve the photo catalytic properties and to find new applications for TiO 2 as a photo catalyst. In this article we reported the synthesis of a photo catalyst based on TiO 2 doped with Zn 2+ ions highly efficient in the degradation of nitrobenzene. The results of photo catalytic activity experiments showed that the Zn 2+ doped TiO 2 is more active that un-doped TiO 2 catalyst with an efficiency of 99% for the nitrobenzene degradation at 120 min with an apparent rate constant of 35 x 10 -3 min -1 . For the characterization of photo catalyst X-ray diffraction, transmission electron microscopy and Raman spectroscopy were used. (Author)

Physical properties and characterization of Ag doped CdS thin films

International Nuclear Information System (INIS)

Shah, N.A.; Nazir, A.; Mahmood, W.; Syed, W.A.A.; Butt, S.; Ali, Z.; Maqsood, A.

2012-01-01

Highlights: ► CdS thin films were grown. ► By ion exchange, Ag was doped. ► Physical properties were investigated. - Abstract: Thin films of cadmium sulfide with very well defined preferential orientation and relatively high absorption coefficient were fabricated by thermal evaporation technique. The research is focused to the fabrication and characterization of the compositional data of CdS thin films obtained by using X-ray diffraction, scanning electron microscope along with energy dispersive X-ray spectroscopy. The optical properties were studied by using a UV-VIS-NIR spectrophotometer. The effects of silver-doping by ion exchange process on the properties of as-deposited CdS thin films have been investigated.

Molecular basis of cadmium toxicity

Energy Technology Data Exchange (ETDEWEB)

Nath, R; Prasad, R; Palinal, V K; Chopra, R K

1984-01-01

Cadmium has been shown to manifest its toxicity in human and animals by mainly accumulating in almost all of the organs. The kidney is the main target organ where it is concentrated mainly in the cortex. Environmental exposure of cadmium occurs via food, occupational industries, terrestrial and aquatic ecosystem. At molecular level, cadmium interferes with the utilization of essential metals e.g. Ca, Zn, Se, Cr and Fe and deficiencies of these essential metals including protein and vitamins, exaggerate cadmium toxicity, due to its increased absorption through the gut and greater retention in different organs as metallothionein (Cd-Mt). Cadmium transport, across the intestinal and renal brush border membrane vesicles, is carrier mediated and it competes with zinc and calcium. It has been postulated that cadmium shares the same transport system. Cadmium inhibits protein synthesis, carbohydrate metabolism and drug metabolizing enzymes in liver of animals. Chronic environmental exposure of cadmium produces hypertension in experimental animals. Functional changes accompanying cadmium nephropathy include low molecular weight proteinuria which is of tubular origin associated with excess excretion of proteins such as beta 2 microglobulin, metallothionein and high molecular weight proteinuria of glomerular origin (excretion of proteins such as albumin IgG, transferrin etc.). Recent data has shown that metallothionein is more nephrotoxic to animals. Cadmium is also toxic to central nervous system. It causes an alterations of cellular functions in lungs. Cadmium affects both humoral and cell mediated immune response in animals. Cadmium induces metallothionein in liver and kidney but under certain nutritional deficiencies like protein-calorie malnutrition and calcium deficiency, enhanced induction and greater accumulation of cadmium metallothionein has been observed.

NATO Advanced Research Workshop on Properties and Applications of Nanocrystalline Alloys from Amorphous Precursors

CERN Document Server

Idzikowski, Bogdan; Miglierini, Marcel

2005-01-01

Metallic (magnetic and non-magnetic) nanocrystalline materials have been known for over ten years but only recent developments in the research into those complex alloys and their metastable amorphous precursors have created a need to summarize the most important accomplishments in the field. This book is a collection of articles on various aspects of metallic nanocrystalline materials, and an attempt to address this above need. The main focus of the papers is put on the new issues that emerge in the studies of nanocrystalline materials, and, in particular, on (i) new compositions of the alloys, (ii) properties of conventional nanocrystalline materials, (iii) modeling and simulations, (iv) preparation methods, (v) experimental techniques of measurements, and (vi) different modern applications. Interesting phenomena of the physics of nanocrystalline materials are a consequence of the effects induced by the nanocrystalline structure. They include interface physics, the influence of the grain boundaries, the aver...

Dielectric response and room temperature ferromagnetism in Cr doped anatase TiO2 nanoparticles

Science.gov (United States)

Naseem, Swaleha; Khan, Wasi; Khan, Shakeel; Husain, Shahid; Ahmad, Abid

2018-02-01

In the present work, nanocrystalline samples of Ti1-xCrxO2 (x = 0, 0.02, 0.04, 0.06 and 0.08) were synthesized in anatase phase through simple and cost effective acid modified sol gel method. The influence of Cr doping on thermal, microstructural, electrical and magnetic properties was investigated in TiO2 host matrix. The surface morphology has revealed less agglomeration and considerable reduction in particle size in case of Cr doped TiO2 as compared to undoped TiO2 nanoparticles (NPs). Energy dispersive x-ray spectroscopy (EDS), Raman and X-ray photoelectron spectroscopy (XPS) established high purity, appropriate stoichiometry and oxidation states of the compositions. The dielectric properties of the nanoparticles were altered by the doping concentration, applied frequency as well as temperature variation. The variation in dielectric constant (ε‧), dielectric loss (δ) and ac conductivity as a function of frequency and temperature at different doping concentration of Cr were interpreted in the light of Maxwell Wagner theory, space charge polarization mechanism and drift mobility of charge carriers. Both undoped and Cr doped TiO2 samples exhibit room temperature ferromagnetism (RTFM) that remarkably influenced by means of the Cr content. The significant enhancement in the magnetization was observed at 4% Cr doping. However, decrease in magnetization for higher doping signify antiferromagnetic interactions between Cr ions or superexchange mechanism. These results reveal that the oxygen vacancies play a crucial role to initiate the RTFM. Therefore, the present investigation suggests the potential applications of Cr doped TiO2 nanoparticles for spintronics application.

Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

Energy Technology Data Exchange (ETDEWEB)

Poffo, C.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.b [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Souza, S.M.; Triches, D.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Biasi, R.S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)

2011-04-01

Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 {sup o}C the heat transfer is controlled by crystalline component.

Photoacoustic study of nanocrystalline silicon produced by mechanical grinding

International Nuclear Information System (INIS)

Poffo, C.M.; Lima, J.C. de; Souza, S.M.; Triches, D.M.; Grandi, T.A.; Biasi, R.S. de

2011-01-01

Mechanical grinding (MG) was used to produce nanocrystalline silicon and its thermal and transport properties were investigated by photoacoustic absorption spectroscopy (PAS). The experimental results suggest that in as-milled nanocrystalline silicon for 10 h the heat transfer through the crystalline and interfacial components is similar, and after annealed at 470 o C the heat transfer is controlled by crystalline component.

Reversal of exchange bias in nanocrystalline antiferromagnetic-ferromagnetic bilayers

International Nuclear Information System (INIS)

Prados, C; Pina, E; Hernando, A; Montone, A

2002-01-01

The sign of the exchange bias in field cooled nanocrystalline antiferromagnetic-ferromagnetic bilayers (Co-O and Ni-O/permalloy) is reversed at temperatures approaching the antiferromagnetic (AFM) blocking temperature. A similar phenomenon is observed after magnetic training processes at similar temperatures. These effects can be explained assuming that the boundaries of nanocrystalline grains in AFM layers exhibit lower transition temperatures than grain cores

Investigation of the optoelectronic behavior of Pb-doped CdO nanostructures

Science.gov (United States)

Eskandari, Abdollah; Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

2018-03-01

Un- and lead (Pb)-doped cadmium oxide (CdO) semiconductor nanostructures were synthesized by a sonochemical method to study their physical properties. The obtained X-ray diffraction (XRD) patterns indicated cubic CdO crystalline structures for all samples and showed that the crystallite size of CdO increases with Pb addition. Scanning electron microscopy (SEM) images of the nanostructures illustrated agglomerated oak-like particles for the Pb-doped CdO nanostructures. Furthermore, optical studies suggested that the emission band gap energy of the CdO nanostructures lies in the range of 2.27-2.38 eV and crystalline defects increase by incorporation of Pb atoms in the CdO crystalline lattice. In addition, electrical experiments declared that the n-type electrical nature of the un- and Pb-doped CdO nanostructures and the minimum of Pb atoms lead to a high carrier concentration.

Characterization of photoluminescent europium doped yttrium oxide thin-films prepared by metallorganic chemical vapor deposition

International Nuclear Information System (INIS)

McKittrick, J.; Bacalski, C.F.; Hirata, G.A.; Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M.

1998-01-01

Europium doped yttrium oxide, (Y 1-x Eu x ) 2 O 3 , thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y 2 O 3 , grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y 2 O 3 :Eu 3+ was observed in x-ray diffraction for deposition temperatures ≥600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra

Cadmium-containing waste and recycling possibilities

International Nuclear Information System (INIS)

Wiegand, V.; Rauhut, A.

1981-01-01

To begin with, the processes of cadmium production from zinc ores in smelting plants or from intermediates of other metal works are described. A considerable amount of the cadmium is obtained in the recycling process in zinc, lead, and copper works. The way of the cadmium-containing intermediaries, processing, enrichment, and disposal of cadmium waste are described. Uses of cadmium and its compounds are mentioned, and cadmium consumption in the years 1973-1977 in West Germany is presented in a table. Further chapters discuss the production and the way of waste during production and processing of cadmium-containing products, the problem of cadmium in household refuse and waste incineration plants, and the problem of cadmium emissions. (IHOE) [de

Low-temperature magnetoresistance study of electrical transport in N- and B-doped ultrananocrystalline and nanocrystalline diamond films

Czech Academy of Sciences Publication Activity Database

Nesládek, M.; Tromson, D.; Bergonzo, P.; Hubík, Pavel; Mareš, Jiří J.; Krištofik, Jozef; Kindl, Dobroslav; Williams, O.A.; Gruen, D.

2006-01-01

Roč. 15, - (2006), s. 607-613 ISSN 0925-9635 R&D Projects: GA AV ČR(CZ) IAA1010404; GA ČR(CZ) GA202/06/0040 Institutional research plan: CEZ:AV0Z10100521 Keywords : U-NCD * NCD * doping * low-temperature doping * weak localisation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.935, year: 2006

Influence of film thickness and Fe doping on LPG sensing properties of Mn3O4 thin film grown by SILAR method

Science.gov (United States)

Belkhedkar, M. R.; Ubale, A. U.

2018-05-01

Nanocrystalline Fe doped and undoped Mn3O4 thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method onto glass substrates using MnCl2 and NaOH as cationic and anionic precursors. The grazing incidence X-ray diffraction (GIXRD) and field emission scanning electron microscopy (FESEM)) have been carried out to analyze structural and surface morphological properties of the films. The LPG sensing performance of Mn3O4thin films have been studied by varying temperature, concentration of LPG, thickness of the film and doping percentage of Fe. The LPG response of the Mn3O4thin films were found to be enhances with film thickness and decreases with increased Fe doping (0 to 8 wt. %) at 573 K temperature.

Murine strain differences and the effects of zinc on cadmium concentrations in tissues after acute cadmium exposure

Energy Technology Data Exchange (ETDEWEB)

King, L.M. [ARS USDA, Germplasm and Gamete Physiology Lab., Beltsville, MD (United States); Anderson, M.B. [Dept. of Anatomy, Tulane Univ. School of Medicine, New Orleans, LA (United States); Sikka, S.C. [Dept. of Urology, Tulane Univ. School of Medicine, New Orleans, LA (United States); George, W.J. [Dept. of Pharmacology, Tulane Univ. School of Medicine, New Orleans, LA (United States)

1998-10-01

The role of strain differences in cadmium tissue distribution was studied using sensitive (129/J) and resistant (A/J) mice. These murine strains have previously been shown to differ in their susceptibility to cadmium-induced testicular toxicity. Cadmium concentration was measured in testis, epididymis, seminal vesicle, liver, and kidney at 24 h after cadmium chloride exposure (4, 10, and 20 {mu}mol/kg CdCl{sub 2}). The 129/J mice exhibited a significant increase in cadmium concentration in testis, epididymis, and seminal vesicle at all cadmium doses used, compared to A/J mice. However, cadmium concentrations in liver and kidney were not different between the strains, at any dose, indicating that cadmium uptake is similar in these organs at 24 h. These murine strains demonstrate similar hepatic and renal cadmium uptake but significantly different cadmium accumulation in the reproductive organs at 24 h. The mechanism of the protective effect of zinc on cadmium toxicity was studied by assessing the impact of zinc acetate (ZnAc) treatment on cadmium concentrations in 129/J mice after 24 h. Zinc pretreatment (250 {mu}mol/kg ZnAc), given 24 h prior to 20 {mu}mol/kg CdCl{sub 2} administration, significantly decreased the amount of cadmium in the testis, epididymis, and seminal vesicle of 129/J mice, and significantly increased the cadmium content of the liver after 24 h. Cadmium levels in the kidney were unaffected at this time. Zinc pretreatment also prevented the cadmium-induced decrease in testicular sperm concentration and epididymal sperm motility seen in 129/J mice. These findings suggest that the differences in the two murine strains may be attributed partly to the differential accumulation of cadmium in murine gonads. This may be caused by strain differences in the specificity of cadmium transport mechanisms. The protective role of zinc in cadmium-induced testicular toxicity in the sensitive strain may be due to an interference in the cadmium uptake by susceptible

Ferromagnetism appears in nitrogen implanted nanocrystalline diamond films

Energy Technology Data Exchange (ETDEWEB)

Remes, Zdenek [Institute of Physics ASCR v.v.i., Cukrovarnicka 10, 162 00 Prague 6 (Czech Republic); Sun, Shih-Jye, E-mail: sjs@nuk.edu.tw [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China); Varga, Marian [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China); Chou, Hsiung [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Hsu, Hua-Shu [Department of Applied Physics, National Pingtung University of Education, Pingtung 900, Taiwan (China); Kromka, Alexander [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China); Horak, Pavel [Nuclear Physics Institute, 250 68 Rez (Czech Republic)

2015-11-15

The nanocrystalline diamond films turn to be ferromagnetic after implanting various nitrogen doses on them. Through this research, we confirm that the room-temperature ferromagnetism of the implanted samples is derived from the measurements of magnetic circular dichroism (MCD) and superconducting quantum interference device (SQUID). Samples with larger crystalline grains as well as higher implanted doses present more robust ferromagnetic signals at room temperature. Raman spectra indicate that the small grain-sized samples are much more disordered than the large grain-sized ones. We propose that a slightly large saturated ferromagnetism could be observed at low temperature, because the increased localization effects have a significant impact on more disordered structure. - Highlights: • Nitrogen implanted nanocrystalline diamond films exhibit ferromagnetism at room temperature. • Nitrogen implants made a Raman deviation from the typical nanocrystalline diamond films. • The ferromagnetism induced from the structure distortion is dominant at low temperature.

Nanocrystalline Aluminum Truss Cores for Lightweight Sandwich Structures

Science.gov (United States)

Schaedler, Tobias A.; Chan, Lisa J.; Clough, Eric C.; Stilke, Morgan A.; Hundley, Jacob M.; Masur, Lawrence J.

2017-12-01

Substitution of conventional honeycomb composite sandwich structures with lighter alternatives has the potential to reduce the mass of future vehicles. Here we demonstrate nanocrystalline aluminum-manganese truss cores that achieve 2-4 times higher strength than aluminum alloy 5056 honeycombs of the same density. The scalable fabrication approach starts with additive manufacturing of polymer templates, followed by electrodeposition of nanocrystalline Al-Mn alloy, removal of the polymer, and facesheet integration. This facilitates curved and net-shaped sandwich structures, as well as co-curing of the facesheets, which eliminates the need for extra adhesive. The nanocrystalline Al-Mn alloy thin-film material exhibits high strength and ductility and can be converted into a three-dimensional hollow truss structure with this approach. Ultra-lightweight sandwich structures are of interest for a range of applications in aerospace, such as fairings, wings, and flaps, as well as for the automotive and sports industries.

Syntheses of nanocrystalline BaTiO3 and their optical properties

Science.gov (United States)

Yu, J.; Chu, J.; Zhang, M.

Stoichiometric and titanium-excess nanocrystalline barium titanates were synthesized using a hydrothermal process at various hydrothermal temperatures and with further heat treatment at 500 °C and 900 °C. Owing to the different process conditions, the excess titanium exists in different states and configurations within the nanocrystalline BaTiO3 matrix; this was demonstrated by X-ray diffraction, Raman scattering, and photoluminescence. In these nanocrystalline BaTiO3, the 590, 571, 543 and 694 nm light emission bands were observed; mechanisms leading to such emissions were also discussed.

Electrochemistry of Inorganic Nanocrystalline Electrode Materials for Lithium Batteries

Directory of Open Access Journals (Sweden)

C. W. Kwon

2003-01-01

much different from that of traditional crystalline ones because of their significant ‘surface effects’. In connection with that, the nanocrystalline cathode materials are reported to have an enhanced electrochemical activity when the first significative electrochemical step is insertion of Li ions (discharge process. The “electrochemical grafting” concept will be given as a plausible explanation. As illustrative examples, electrochemical behaviors of nanocrystalline manganese oxydes are presented.

Cadmium in Sweden - environmental risks

Energy Technology Data Exchange (ETDEWEB)

Parkman, H; Iverfeldt, Aa [Swedish Environmental Research Inst. (Sweden); Borg, H; Lithner, G [Stockholm Univ. (Sweden). Inst. for Applied Environmental Research

1998-03-01

This report aims at assessing possible effects of cadmium in the Swedish environment. Swedish soils and soft freshwater systems are, due to a generally poor buffering capacity, severely affected by acidification. In addition, the low salinity in the Baltic Sea imply a naturally poor organism structure, with some important organisms living close to their limit of physiological tolerance. Cadmium in soils is mobilized at low pH, and the availability and toxicity of cadmium in marine systems are enhanced at low salinity. The Swedish environment is therefore extra vulnerable to cadmium pollution. The average concentrations of cadmium in the forest mor layers, agricultural soils, and fresh-waters in Sweden are enhanced compared to `back-ground concentrations`, with a general increasing trend from the north to the south-west, indicating strong impact of atmospheric deposition of cadmium originating from the central parts of Europe. In Swedish sea water, total cadmium concentrations, and the fraction of bio-available `free` cadmium, generally increases with decreasing salinity. Decreased emissions of cadmium to the environment have led to decreasing atmospheric deposition during the last decade. The net accumulation of cadmium in the forest mor layer has stopped, and even started to decrease. In northern Sweden, this is due to the decreased deposition, but in southern Sweden the main reason is increased leakage of cadmium from the topsoil as a consequence of acidification. As a result, cadmium in the Swedish environments is undergoing an extended redistribution between different soil compartments, and from the soils to the aquatic systems. 90 refs, 23 figs, 2 tabs. With 3 page summary in Swedish

Determination of cadmium selenide nonstoichiometry

International Nuclear Information System (INIS)

Brezhnev, V.Yu.; Kharif, Ya.L.; Kovtunenko, P.V.

1986-01-01

Physicochemical method of determination of cadmium selenide nonstoichiometry is developed. The method nature consists in the fact, that under definite conditions dissolved cadmium is extracted from crystals to a vapor phase and then is determined in it using the photocolorimetric method. Cadmium solubility in CdSe crystal is calculated from known CdSe mass and amount of separated cadmium. The lower boundary of determined contents constitutes 1x10 -5 % mol at sample of cadmium selenide 10 g

High-pressure structural behaviour of nanocrystalline Ge

International Nuclear Information System (INIS)

Wang, H; Liu, J F; He, Y; Wang, Y; Chen, W; Jiang, J Z; Olsen, J Staun; Gerward, L

2007-01-01

The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transition remains constant. Simplified models for the high-pressure structural behaviour are presented, based on the assumption that a large fraction of the atoms reside in grain boundary regions of the nanocrystalline material. The interface structure plays a significant role in affecting the transition pressure and the bulk modulus

Studies on phase evolution and electrical conductivity of barium doped gadolinium aluminate

International Nuclear Information System (INIS)

Sinha, Amit; Sharma, B.P.; Gopalan, P.

2012-01-01

Highlights: ► Barium doped GdAlO 3 compositions were prepared from citrate gel derived powders. ► The solid solubility of barium in GdAlO 3 was less than 4 mol%. ► The un-dissolved barium precipitated in the form of BaAl 2 O 4 phase. ► The conductivity of Ba-doped GdAlO 3 increased with increasing amounts of Ba. ► In Gd 1−x Ba x AlO 3−δ system, specimen with x = 0.02 exhibited maximum conductivity. - Abstract: The phase evolution and electrical conductivity of barium doped GdAlO 3 samples have been investigated. The Ba- doped compositions of GdAlO 3 were prepared through citrate gel process. Analysis of the phases was carried out using X-ray diffraction (XRD). The morphology of the calcined powders was studied by scanning electron microscopy. The electrical conductivity of Gd 1−x Ba x AlO 3−δ (x = 0–0.04) was measured using ac impedance spectroscopy as a function of temperature ranging from 300 to 1000 °C under air. The solid solubility of barium in GdAlO 3 was found to be less than 4 mol%. The undissolved barium precipitated in the form of BaAl 2 O 4 phase. The barium doped GdAlO 3 powders obtained after calcination at 1000 °C was found to be porous agglomerate composed of nanocrystalline grains. The total electrical conductivity of Ba-doped GdAlO 3 increased with increasing amounts of barium up to 2 mol% doping.

Electron beam induced green luminescence and degradation study of CaS:Ce nanocrystalline phosphors for FED applications

Energy Technology Data Exchange (ETDEWEB)

Kumar, Vinay, E-mail: vinaykdhiman@yahoo.com [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa); Mishra, Varun [Department of Physics, Lovely Professional University, Phagwara 144 402, Punjab (India); Biggs, M.M.; Nagpure, I.M.; Ntwaeaborwa, O.M.; Terblans, J.J. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa); Swart, H.C., E-mail: swarthc.sci@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa)

2010-01-01

Green luminescence and degradation of Ce{sup 3+} doped CaS nanocrystalline phosphors were studied with a 2 keV, 10 {mu}A electron beam in an O{sub 2} environment. The nanophosphors were synthesized by the co-precipitation method. The samples were characterized using X-ray diffraction, Transmission electron microscopy, Scanning electron microscopy/electron dispersive X-ray spectroscopy and Photoluminescence (PL) spectroscopy. Cubic CaS with an average particle size of 42 {+-} 2 nm was obtained. PL emission was observed at 507 nm and a shoulder at 560 nm with an excitation wavelength of 460 nm. Auger electron spectroscopy and Cathodoluminescence (CL) were used to monitor the changes in the surface composition of the CaS:Ce{sup 3+} nanocrystalline phosphors during electron bombardment in an O{sub 2} environment. The effect of different oxygen pressures ranging from 1 x 10{sup -8} to 1 x 10{sup -6} Torr on the CL intensity was also investigated. A CaSO{sub 4} layer was observed on the surface after the electron beam degradation. The CL intensity was found to decrease up to 30% of its original intensity at 1 x 10{sup -6} Torr oxygen pressure after an electron dose of 50 C/cm{sup 2}. The formation of oxygen defects during electron bombardment may also be responsible for the decrease in CL intensity.

Electron beam induced green luminescence and degradation study of CaS:Ce nanocrystalline phosphors for FED applications

International Nuclear Information System (INIS)

Kumar, Vinay; Mishra, Varun; Biggs, M.M.; Nagpure, I.M.; Ntwaeaborwa, O.M.; Terblans, J.J.; Swart, H.C.

2010-01-01

Green luminescence and degradation of Ce 3+ doped CaS nanocrystalline phosphors were studied with a 2 keV, 10 μA electron beam in an O 2 environment. The nanophosphors were synthesized by the co-precipitation method. The samples were characterized using X-ray diffraction, Transmission electron microscopy, Scanning electron microscopy/electron dispersive X-ray spectroscopy and Photoluminescence (PL) spectroscopy. Cubic CaS with an average particle size of 42 ± 2 nm was obtained. PL emission was observed at 507 nm and a shoulder at 560 nm with an excitation wavelength of 460 nm. Auger electron spectroscopy and Cathodoluminescence (CL) were used to monitor the changes in the surface composition of the CaS:Ce 3+ nanocrystalline phosphors during electron bombardment in an O 2 environment. The effect of different oxygen pressures ranging from 1 x 10 -8 to 1 x 10 -6 Torr on the CL intensity was also investigated. A CaSO 4 layer was observed on the surface after the electron beam degradation. The CL intensity was found to decrease up to 30% of its original intensity at 1 x 10 -6 Torr oxygen pressure after an electron dose of 50 C/cm 2 . The formation of oxygen defects during electron bombardment may also be responsible for the decrease in CL intensity.

Effect of grain size on corrosion of nanocrystalline copper in NaOH solution

International Nuclear Information System (INIS)

Luo Wei; Xu Yimin; Wang Qiming; Shi Peizhen; Yan Mi

2010-01-01

Research highlights: → Coppers display an active-passive-transpassive behaviour with duplex passive film. → Grain size variation has little effect on the overall corrosion behaviour of Cu. → Little effect on corrosion may be due to duplex passivation in NaOH solution. → Bulk nanocrystalline Cu show bamboo-like flake corrosion structure. - Abstract: Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1 M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92 nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active-passive-transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples.

Structural, optical and magnetic properties of nanocrystalline Co-doped ZnO thin films grown by sol-gel

Energy Technology Data Exchange (ETDEWEB)

Kayani, Zohra Nazir; Shah, Iqra; Zulfiqar, Bareera; Sabah, Aneeqa [Lahore College for Women Univ., Lahore (Pakistan); Riaz, Saira; Naseem, Shahzad [Univ. of the Punjab, Lahore (Pakistan). Centre of Excellence in Solid State Physics

2018-04-01

Cobalt-doped ZnO thin films have been deposited using a sol-gel route by changing the number of coats on the substrate from 6 to 18. This project deals with various film thicknesses by increasing the number of deposited coats. The effect of thickness on structural, magnetic, surface morphology and optical properties of Co-doped ZnO thin film was studied. The crystal structure of the Co-doped ZnO films was investigated by X-ray diffraction. The films have polycrystalline wurtzite hexagonal structures. A Co{sup 2+} ion takes the place of a Zn{sup 2+} ion in the lattice without creating any distortion in its hexagonal wurtzite structure. An examination of the optical transmission spectra showed that the energy band gap of the Co-doped ZnO films increased from 3.87 to 3.97 eV with an increase in the number of coatings on the substrate. Ferromagnetic behaviour was confirmed by measurements using a vibrating sample magnetometer. The surface morphology of thin films was assessed by scanning electron microscope. The grain size on the surface of thin films increased with an increase in the number of coats.

Mechanochemical synthesis of nanocrystalline Fe and Fe–B magnetic alloys

International Nuclear Information System (INIS)

Mohammadi, Majid; Ghasemi, Ali; Tavoosi, Majid

2016-01-01

Mechanochemical synthesis and magnetic characterization of nanocrystalline Fe and Fe–B magnetic alloys was the goal of this study. In this regard, different Fe_2O_3–B_2O_3 powder mixtures with sufficient amount of CaH_2 were milled in a planetary ball mill in order to produce nanocrystalline Fe, Fe_9_5B_5 and Fe_8_5B_1_5 alloys. The produced samples were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The results showed that, nanocrystalline Fe, Fe_9_5B_5 and Fe_8_5B_1_5 alloys can be successfully synthesized by the reduction reaction of Fe_2O_3 and B_2O_3 with CaH_2 during mechanical alloying. The structure of produced Fe_9_5B_5 and Fe_8_5B_1_5 alloys was a combination of Fe and Fe_2B phases with average crystallite sizes of about 15 and 10 nm, respectively. The produced nanocrystalline alloys exhibited soft magnetic properties with the coercivity and saturation of magnetization in the range of 170–240 Oe and 9–28 emu/g, respectively. Increasing the boron content has a destructive effect on soft magnetic properties of Fe–B alloys. - Highlights: • We study the mechanochemical synthesis of nanocrystalline boron, Fe and Fe–B alloys. • We study the reduction reaction of B_2O_3–CaH_2 during milling. • We study the reduction reaction of Fe_2O_3–CaH_2 during milling. • We study the reduction reaction of Fe_2O_3–B_2O_3–CaH_2 during milling. • We study the effect of B on magnetic properties of nanocrystalline Fe–B alloys.

Relation between dietary cadmium intake and biomarkers of cadmium exposure in premenopausal women accounting for body iron stores

Directory of Open Access Journals (Sweden)

Julin Bettina

2011-12-01

Full Text Available Abstract Background Cadmium is a widespread environmental pollutant with adverse effects on kidneys and bone, but with insufficiently elucidated public health consequences such as risk of end-stage renal diseases, fractures and cancer. Urinary cadmium is considered a valid biomarker of lifetime kidney accumulation from overall cadmium exposure and thus used in the assessment of cadmium-induced health effects. We aimed to assess the relationship between dietary cadmium intake assessed by analyses of duplicate food portions and cadmium concentrations in urine and blood, taking the toxicokinetics of cadmium into consideration. Methods In a sample of 57 non-smoking Swedish women aged 20-50 years, we assessed Pearson's correlation coefficients between: 1 Dietary intake of cadmium assessed by analyses of cadmium in duplicate food portions collected during four consecutive days and cadmium concentrations in urine, 2 Partial correlations between the duplicate food portions and urinary and blood cadmium concentrations, respectively, and 3 Model-predicted urinary cadmium concentration predicted from the dietary intake using a one-compartment toxicokinetic model (with individual data on age, weight and gastrointestinal cadmium absorption and urinary cadmium concentration. Results The mean concentration of cadmium in urine was 0.18 (+/- s.d.0.12 μg/g creatinine and the model-predicted urinary cadmium concentration was 0.19 (+/- s.d.0.15 μg/g creatinine. The partial Pearson correlations between analyzed dietary cadmium intake and urinary cadmium or blood concentrations were r = 0.43 and 0.42, respectively. The correlation between diet and urinary cadmium increased to r = 0.54 when using a one-compartment model with individual gastrointestinal cadmium absorption coefficients based on the women's iron status. Conclusions Our results indicate that measured dietary cadmium intake can reasonably well predict biomarkers of both long-term kidney accumulation

[Investigation of urinary cadmium characteristics of the general population in three non-cadmium-polluted rural areas in China].

Science.gov (United States)

Han, Jingxiu; Hu, Ji; Sun, Hong; Jing, Qiqing; Wang, Xiaofeng; Lou, Xiaoming; Ding, Zhen; Chen, Xiaodong; Zhang, Wenli; Shang, Qi

2014-11-01

To investigate the characteristics of urinary cadmium of the non-occupational-cadmium-exposed population in non-cadmium contaminated rural area in China. Randomly selected non-occupational cadmium exposed population 2548 people (male 1290, female 1258) with each gender and age groups, questionnaire surveyed and collected random urine. Urinary cadmium and urinary creatinine (Cr) concentration were tested, excluding urinary Cr 3 g/L. Analyze the impact factors of urinary cadmium and calculated 95% quantile (P95) of urinary cadmium after correction by urinary Cr. Urinary cadmium increased with age and showed an upward trend. The urinary cadmium of the population of ≥ 30 years old was significantly higher than that of populations (China (GB Z17-2002). The urinary cadmium reference value of non-occupational-cadmium-exposed populations is China, but for smoking women over 30 year-old it needs more research to explore.

Nanocrystalline La1-xSrxCo1-yFe yO3 perovskites fabricated by the micro-emulsion route for high frequency response devices fabrications

KAUST Repository

Azhar Khan, Muhammad

2014-09-01

Nanocrystalline La1-xSrxCo1-yFe yO3 (x=0.00-0.60) perovskites were fabricated by a cheap economic route (i.e. micro-emulsion method) and characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). TGA analysis showed ~35% weight loss. The crystallite size determined by XRD and SEM ranged from 30 to 80 nm and ~30 to 50 nm, respectively. The dielectric behavior was evaluated in the range of 1.0×106 Hz to 3.0×10 9 Hz at 298 K, the dielectric parameters resulting appreciably enhanced by co-doping with Sr and Fe. The maximum dielectric parameters (ε′=103.35, ε″=58.92 and tan δ=0.57) were observed for La0.4Sr0.6Co0.4Fe0.6O 3 at 15×106 Hz. Results suggest the potential use of these nanocrystalline perovskites in GHz-operated microwave devices. © 2014 Elsevier Ltd and Techna Group S.r.l.

Synthesis of Mesoporous Nanocrystalline Zirconia by Surfactant-Assisted Hydrothermal Approach.

Science.gov (United States)

Nath, Soumav; Biswas, Ashik; Kour, Prachi P; Sarma, Loka S; Sur, Ujjal Kumar; Ankamwar, Balaprasad G

2018-08-01

In this paper, we have reported the chemical synthesis of thermally stable mesoporous nanocrystalline zirconia with high surface area using a surfactant-assisted hydrothermal approach. We have employed different type of surfactants such as CTAB, SDS and Triton X-100 in our synthesis. The synthesized nanocrystalline zirconia multistructures exhibit various morphologies such as rod, mortar-pestle with different particle sizes. We have characterized the zirconia multistructures by X-ray diffraction study, Field emission scanning electron microscopy, Attenuated total refection infrared spectroscopy, UV-Vis spectroscopy and photoluminescence spectroscopy. The thermal stability of as synthesized zirconia multistructures was studied by thermo gravimetric analysis, which shows the high thermal stability of nanocrystalline zirconia around 900 °C temperature.

Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

OpenAIRE

Idris, Jamaliah; Christian, Chukwuekezie; Gaius, Eyu

2013-01-01

Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC) and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis par...

Accumulation and recovery of defects in ion-irradiated nanocrystalline gold

Energy Technology Data Exchange (ETDEWEB)

Chimi, Y. E-mail: chimi@popsvr.tokai.jaeri.go.jp; Iwase, A.; Ishikawa, N.; Kobiyama, M.; Inami, T.; Okuda, S

2001-09-01

Effects of 60 MeV {sup 12}C ion irradiation on nanocrystalline gold (nano-Au) are studied. The experimental results show that the irradiation-produced defects in nano-Au are thermally unstable because of the existence of a large volume fraction of grain boundaries. This suggests a possibility of the use of nanocrystalline materials as irradiation-resistant materials.

Optical characterization of Eu3+ and Tb3+ ions doped cadmium lithium alumino fluoro boro tellurite glasses.

Science.gov (United States)

Raju, K Vemasevana; Sailaja, S; Raju, C Nageswara; Reddy, B Sudhakar

2011-06-01

This article reports on the development and spectral results of Eu(3+) and Tb(3+) ions doped cadmium lithium alumino fluoro boro tellurite (CLiAFBT) glasses in the following composition. 40TeO2-30B2O3-10CdO-10Li2O-10AlF3 (Hostglass) (40-x)TeO2-30B2O3-10CdO-10Li2O-10AlF3-xEu2O3 (40-x)TeO2-30B2O3-10CdO-10Li2O-10AlF3-xTb4O7 where x=0.25, 0.50, 0.75, 1.0, 1.25 mol%. Glass amorphous nature and thermal properties have been studied using the XRD and DSC profiles. From the emission spectra of Eu(3+):glasses, five emission transitions have been observed at 578 nm, 592 nm, 612 nm, 653 nm, 701 nm and are assigned to the transitions (5)D(0)→(7)F(0), (7)F(1,)(7)F(2), (7)F(3) and (7)F(4), respectively, with λ(exci)=392 nm ((7)F(0)→(5)L(6)). In case of Tb(3+):glasses, four emission transitions ((5)D(4)→(7)F(6,)(7)F(5), (7)F(4) and (7)F(3)) are observed at 488 nm, 543 nm, 584 nm and 614 nm, respectively, with λ(exci)=376 nm. Decay curves and energy level diagrams have been plotted to evaluate the life times and to analyze the emission mechanism. Copyright © 2011 Elsevier B.V. All rights reserved.

Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

Directory of Open Access Journals (Sweden)

Dian Siswanto

2013-05-01

Full Text Available The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N, Cd soils (Cds, and Cd soils each amended with 1% w/w of coir pith (CP, coir pith modified with sodium hydroxide (CPm and corncob (CC under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatments under high cadmium contaminated soil followed the order: Cds > CPm ≥ CP ≥ CC. These transpirations directly influenced cadmium accumulation in shoots and husks of rice plants. The CC and CP seemed to work to reduce the cadmium uptake by rice plants indicated by accumulated cadmium in the husk that were 2.47 and 7.38 mg Cd kg-1 dry weight, respectively. Overall, transpiration tended to drive cadmium accumulation in plants for rice grown in high cadmium contaminated soil. The more that plants uptake cadmium, the lower cadmium that remains in the soil.

Synthesis and characterization of sol–gel derived ZnS : Mn ...

Indian Academy of Sciences (India)

Unknown

The films were then (in less than ~ 10 s) transferred to an oven preset at the ... (5 at.%) nanocrystalline ZnS film. Figure 3. d{ln(αhν)}/d(hν) vs hν plots for (a) undoped and. (b) Mn2+ doped nanocrystalline ZnS film (α in cm–1, hν in eV). Figure 1. .... 2⋅8 nm and 2⋅12 nm in case of undoped and doped ZnS nanocrystalline ...

A phenomenological variational multiscale constitutive model for intergranular failure in nanocrystalline materials

KAUST Repository

Siddiq, A.; El Sayed, Tamer S.

2013-01-01

We present a variational multiscale constitutive model that accounts for intergranular failure in nanocrystalline fcc metals due to void growth and coalescence in the grain boundary region. Following previous work by the authors, a nanocrystalline

Biologically inspired rosette nanotubes and nanocrystalline hydroxyapatite hydrogel nanocomposites as improved bone substitutes

International Nuclear Information System (INIS)

Zhang Lijie; Webster, Thomas J; Rodriguez, Jose; Raez, Jose; Myles, Andrew J; Fenniri, Hicham

2009-01-01

Today, bone diseases such as bone fractures, osteoporosis and bone cancer represent a common and significant public health problem. The design of biomimetic bone tissue engineering materials that could restore and improve damaged bone tissues provides exciting opportunities to solve the numerous problems associated with traditional orthopedic implants. Therefore, the objective of this in vitro study was to create a biomimetic orthopedic hydrogel nanocomposite based on the self-assembly properties of helical rosette nanotubes (HRNs), the osteoconductive properties of nanocrystalline hydroxyapatite (HA), and the biocompatible properties of hydrogels (specifically, poly(2-hydroxyethyl methacrylate), pHEMA). HRNs are self-assembled nanomaterials that are formed from synthetic DNA base analogs in water to mimic the helical nanostructure of collagen in bone. In this study, different geometries of nanocrystalline HA were controlled by either hydrothermal or sintering methods. 2 and 10 wt% nanocrystalline HA particles were well dispersed into HRN hydrogels using ultrasonication. The nanocrystalline HA and nanocrystalline HA/HRN hydrogels were characterized by x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Mechanical testing studies revealed that the well dispersed nanocrystalline HA in HRN hydrogels possessed improved mechanical properties compared to hydrogel controls. In addition, the results of this study provided the first evidence that the combination of either 2 or 10 wt% nanocrystalline HA and 0.01 mg ml -1 HRNs in hydrogels greatly increased osteoblast (bone-forming cell) adhesion up to 236% compared to hydrogel controls. Moreover, this study showed that HRNs stimulated HA nucleation and mineralization along their main axis in a way that is very reminiscent of the HA/collagen assembly pattern in natural bone. In summary, the presently observed excellent properties of the biomimetic nanocrystalline HA/HRN hydrogel composites

Zinc and cadmium monosalicylates

International Nuclear Information System (INIS)

Kharitonov, Yu.Ya.; Tujebakhova, Z.K.

1984-01-01

Zinc and cadmium monosalicylates of the composition MSal, where M-Zn or Cd, Sal - twice deprotonated residue of salicylic acid O-HOC 6 H 4 COOH (H 2 Sal), are singled out and characterized. When studying thermograms, thermogravigrams, IR absorption spectra, roentgenograms of cadmium salicylate compounds (Cd(OC 6 H 4 COO) and products of their thepmal transformations, the processes of thermal decomposition of the compounds have been characterized. The process of cadmium monosalicylate decomposition takes place in one stage. Complete loss of salicylate acido group occurs in the range of 320-460 deg. At this decomposition stage cadmium oxide is formed. A supposition is made that cadmium complex has tetrahedral configuration, at that, each salicylate group plays the role of tetradentate-bridge ligand. The compound evidently has a polymer structure

Microstructure characterization and cation distribution of nanocrystalline cobalt ferrite

Energy Technology Data Exchange (ETDEWEB)

Abbas, Y.M., E-mail: ymabbas@live.com [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Mansour, S.A.; Ibrahim, M.H. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Ali, Shehab E., E-mail: shehab_physics@yahoo.com [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt)

2011-11-15

Nanocrystalline cobalt ferrite has been synthesized using two different methods: ceramic and co-precipitation techniques. The nanocrystalline ferrite phase has been formed after 3 h of sintering at 1000 deg. C. The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction and the Rietveld method. The refinement result showed that the type of the cationic distribution over the tetrahedral and octahedral sites in the nanocrystalline lattice is partially an inverse spinel. The transmission electronic microscope analysis confirmed the X-ray results. The magnetic properties of the samples were characterized using a vibrating sample magnetometer. - Highlights: > The refinement result showed that the cationic distribution over the sites in the lattice is partially an inverse spinel. > The transmission electronic microscope analysis confirmed the X-ray results. > The magnetic properties of the samples were characterized using a vibrating sample magnetometer.

Structure and properties of nanocrystalline soft magnetic composite materials with silicon polymer matrix

International Nuclear Information System (INIS)

Dobrzanski, L.A.; Nowosielski, R.; Konieczny, J.; PrzybyI, A.; WysIocki, J.

2005-01-01

The paper concerns investigation of nanocrystalline composites technology preparation. The composites in the form of rings with rectangular transverse section, and with polymer matrix and nanocrystalline metallic powders fulfillment were made, for obtaining good ferromagnetic properties. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses strips in an as-quenched state. Generally for investigation, Co matrix alloys with the silicon polymer were used. Magnetic properties in the form of hysteresis loop by rings method were measured. Generally composite cores showed lower soft ferromagnetic properties than winded cores of nanocrystalline strips, but composite cores showed interesting mechanical properties. Furthermore, the structure of strips and powders on properties of composites were investigated

Ultraviolet photosensitivity of sulfur-doped micro- and nano-crystalline diamond

International Nuclear Information System (INIS)

Mendoza, Frank; Makarov, Vladimir; Hidalgo, Arturo; Weiner, Brad; Morell, Gerardo

2011-01-01

The room-temperature photosensitivity of sulfur-doped micro- (MCD), submicro- (SMCD) and nano- (NCD) crystalline diamond films synthesized by hot-filament chemical vapor deposition was studied. The structure and composition of these diamond materials were characterized by Raman spectroscopy, scanning electron microscopy and X-ray diffraction. The UV sensitivity and response time were studied for the three types of diamond materials using a steady state broad UV excitation source and two pulsed UV laser radiations. It was found that they have high sensitivity in the UV region, as high as 10 9 sec -1 mV -1 range, linear response in a broad spectral range below 320 nm, photocurrents around ∼10 -5 A, and short response time better than 100 ns, which is independent of fluency intensity. A phenomenological model was applied to help understand the role of defects and dopant concentration on the materials' photosensitivity

Silver film on nanocrystalline TiO{sub 2} support: Photocatalytic and antimicrobial ability

Energy Technology Data Exchange (ETDEWEB)

Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Tomašević-Ilić, Tijana D., E-mail: tommashev@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Zarubica, Aleksandra R., E-mail: zarubica2000@yahoo.com [Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš (Serbia); Dimitrijević, Suzana, E-mail: suzana@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Budimir, Milica D., E-mail: mickbudimir@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Vranješ, Mila R., E-mail: mila@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Šaponjić, Zoran V., E-mail: saponjic@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

2014-12-15

Highlights: • Simple photocatalytic rout for deposition of Ag on nanocrystalline TiO{sub 2} films. • High antibactericidal efficiency of deposited Ag on TiO{sub 2} support. • Improved photocatalytic performance of TiO{sub 2} films in the presence of deposited Ag. - Abstract: Nanocrystalline TiO{sub 2} films were prepared on glass slides by the dip coating technique using colloidal solutions consisting of 4.5 nm particles as a precursor. Photoirradiation of nanocrystalline TiO{sub 2} film modified with alanine that covalently binds to the surface of TiO{sub 2} and at the same time chelate silver ions induced formation of metallic silver film. Optical and morphological properties of thin silver films on nanocrystalline TiO{sub 2} support were studied by absorption spectroscopy and atomic force microscopy. Improvement of photocatalytic performance of nanocrystalline TiO{sub 2} films after deposition of silver was observed in degradation reaction of crystal violet. Antimicrobial ability of deposited silver films on nanocrystalline TiO{sub 2} support was tested in dark as a function of time against Escherichia coli, Staphylococcus aureus, and Candida albicans. The silver films ensured maximum cells reduction of both bacteria, while the fungi reduction reached satisfactory 98.45% after 24 h of contact.

DFT Calculations using WIEN2K to determine oxygen defect structure of rare earth doped ceria

CERN Document Server

Khalife, Ali Rida

2014-01-01

We perform density functional calculations using the program WIEN2K in order to study oxygen vacancies in rare earth doped ceria. The calculation for all rare earth elements were prepared, however only those foe Cadmium and Europium were performed due to lack of time. Also a short description of my stay at CERN was presented

Direct Coating of Nanocrystalline Diamond on Steel

Science.gov (United States)

Tsugawa, Kazuo; Kawaki, Shyunsuke; Ishihara, Masatou; Hasegawa, Masataka

2012-09-01

Nanocrystalline diamond films have been successfully deposited on stainless steel substrates without any substrate pretreatments to promote diamond nucleation, including the formation of interlayers. A low-temperature growth technique, 400 °C or lower, in microwave plasma chemical vapor deposition using a surface-wave plasma has cleared up problems in diamond growth on ferrous materials, such as the surface graphitization, long incubation time, substrate softening, and poor adhesion. The deposited nanocrystalline diamond films on stainless steel exhibit good adhesion and tribological properties, such as a high wear resistance, a low friction coefficient, and a low aggression strength, at room temperature in air without lubrication.

Cadmium in blood and hypertension

Energy Technology Data Exchange (ETDEWEB)

Eum, Ki-Do; Lee, Mi-Sun [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of); Paek, Domyung [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of)], E-mail: paekdm@snu.ac.kr

2008-12-15

Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 {mu}g/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 {mu}g/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.

Cadmium in blood and hypertension

International Nuclear Information System (INIS)

Eum, Ki-Do; Lee, Mi-Sun; Paek, Domyung

2008-01-01

Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 μg/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 μg/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population

Cadmium induces cadmium-tolerant gene expression in the filamentous fungus Trichoderma harzianum.

Science.gov (United States)

Cacciola, Santa O; Puglisi, Ivana; Faedda, Roberto; Sanzaro, Vincenzo; Pane, Antonella; Lo Piero, Angela R; Evoli, Maria; Petrone, Goffredo

2015-11-01

The filamentous fungus Trichoderma harzianum, strain IMI 393899, was able to grow in the presence of the heavy metals cadmium and mercury. The main objective of this research was to study the molecular mechanisms underlying the tolerance of the fungus T. harzianum to cadmium. The suppression subtractive hybridization (SSH) method was used for the characterization of the genes of T. harzianum implicated in cadmium tolerance compared with those expressed in the response to the stress induced by mercury. Finally, the effects of cadmium exposure were also validated by measuring the expression levels of the putative genes coding for a glucose transporter, a plasma membrane ATPase, a Cd(2+)/Zn(2+) transporter protein and a two-component system sensor histidine kinase YcbA, by real-time-PCR. By using the aforementioned SSH strategy, it was possible to identify 108 differentially expressed genes of the strain IMI 393899 of T. harzianum grown in a mineral substrate with the addition of cadmium. The expressed sequence tags identified by SSH technique were encoding different genes that may be involved in different biological processes, including those associated to primary and secondary metabolism, intracellular transport, transcription factors, cell defence, signal transduction, DNA metabolism, cell growth and protein synthesis. Finally, the results show that in the mechanism of tolerance to cadmium a possible signal transduction pathway could activate a Cd(2+)/Zn(2+) transporter protein and/or a plasma membrane ATPase that could be involved in the compartmentalization of cadmium inside the cell.

Inter- and intra-agglomerate fracture in nanocrystalline nickel.

Science.gov (United States)

Shan, Zhiwei; Knapp, J A; Follstaedt, D M; Stach, E A; Wiezorek, J M K; Mao, S X

2008-03-14

In situ tensile straining transmission electron microscopy tests have been carried out on nanocrystalline Ni. Grain agglomerates (GAs) were found to form very frequently and rapidly ahead of an advancing crack with sizes much larger than the initial average grain size. High-resolution electron microscopy indicated that the GAs most probably consist of nanograins separated by low-angle grain boundaries. Furthermore, both inter- and intra-GA fractures were observed. The observations suggest that these newly formed GAs may play an important role in the formation of the dimpled fracture surfaces of nanocrystalline materials.

Correlation of thermodynamics and grain growth kinetics in nanocrystalline metals

International Nuclear Information System (INIS)

Song Xiaoyan; Zhang Jiuxing; Li Lingmei; Yang Keyong; Liu Guoquan

2006-01-01

We investigated the correlation of thermodynamics and grain growth kinetics of nanocrystalline metals both theoretically and experimentally. A model was developed to describe the thermodynamic properties of nanograin boundaries, which could give reliable predictions in the destabilization characteristics of nanograin structures and the slowing down of grain growth kinetics at a constant temperature. Both the temperature-varying and isothermal nanograin growth behaviors in pure nanocrystalline Co were studied to verify the thermodynamic predictions. The experimental results showing that discontinuous nanograin growth takes place at a certain temperature and grain growth rate decreases monotonically with time confirm our thermodynamics-based description of nanograin growth characteristics. Therefore, we propose a thermodynamic viewpoint to explain the deviation of grain growth kinetics in nanocrystalline metals from those of polycrystalline materials

Fabrication and structure of bulk nanocrystalline Al-Si-Ni-mishmetal alloys

International Nuclear Information System (INIS)

Latuch, Jerzy; Cieslak, Grzegorz; Kulik, Tadeusz

2007-01-01

Al-based alloys of structure consisting of nanosized Al crystals, embedded in an amorphous matrix, are interesting for their excellent mechanical properties, exceeding those of the commercial crystalline Al-based alloys. Recently discovered nanocrystalline Al alloys containing silicon (Si), rare earth metal (RE) and late transition metal (Ni), combine high tensile strength and good wear resistance. The aim of this work was to manufacture bulk nanocrystalline alloys from Al-Si-Ni-mishmetal (Mm) system. Bulk nanostructured Al 91-x Si x Ni 7 Mm 2 (x = 10, 11.6, 13 at.%) alloys were produced by ball milling of nanocrystalline ribbons followed by high pressure hot isostating compaction

Structural, magnetic and dielectric investigations in antimony doped nano-phased nickel-zinc ferrites

Energy Technology Data Exchange (ETDEWEB)

Lakshmi, Ch.S. [Department of Physics, Regency Institute of Technology, Adivipolam Yanam 533464, Pondicherry (India); Sridhar, Ch.S.L.N. [Department of Physics, Vignana Bharathi Institute of Technology, Aushapur(v) Ghatkesar (M), Hyderabad 501301, Telangana (India); Govindraj, G. [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V.Nagar, Kalapet, Pondicherry 605014 (India); Bangarraju, S. [Department of Physics, Andhra University, Visakhapatnam 530003, Andhrapradesh (India); Potukuchi, D.M., E-mail: potukuchidm@yahoo.com [Department of Physics, University College of Engineering, Jawaharlal Nehru Technological University:Kakinada, Kakinada 533003 (India)

2015-02-15

Nanocrystalline Ni–Zn–Sb ferrites synthesized by hydrothermal method are reported. Influence of Sb{sup 5+} ions on structural, magnetic and dielectric properties of ferrites is studied. Phase identification, lattice parameter and crystallite size studies are carried out using by X-ray diffraction (XRD). Addition of dopant resulted for decrease in lattice parameter. Crystallite size gets reduced from 62 nm to 38 nm with doping of Antimony. Crystallite size and porosity exhibit similar trends with doping. Morphological study is carried out by Field Emission Scanning Electron Microscopy (FESEM). Strong FTIR absorption bands at 400–600 cm{sup −1} confirm the formation of ferrite structure. Increase of porosity is attributed to the grain size. Doping with Antimony results for decrease in saturation magnetization and increase in coercivity. An initial increase of saturation magnetization for x=0.1 is attributed to the unusually high density. Reversed trend of coercivity with crystallite size are observed. Higher value of dielectric constant ε′(ω) is attributed to the formation of excess of Fe{sup 2+} ions caused by aliovalent doping of Sb{sup 5+} ions. Variation of dielectric constant infers hopping type of conductivity mechanism. The dielectric loss factor tanδ attains lower values of ∼10{sup −2}. High ac resistivity ρ(ω) of 10{sup 8} Ω cm is witnessed for antimony doped ferrites. Higher saturation magnetization and enhanced dielectric response directs for a possible utility as microwave oscillators and switches.

EXAFS and XRD studies of nanocrystalline cerium oxide: the effect of preparation method on the microstructure

International Nuclear Information System (INIS)

Savin, S.L.P.; Chadwick, A.V.; Smith, M.E.; O'Dell, L.A.

2007-01-01

There is considerable interest in nanocrystalline materials due to their unusual properties, such as enhanced ionic conductivity in the case of nanocrystalline ionic solids. This has potential commercial applications, particularly for oxide ion conductors. However, a detailed knowledge of the microstructure is important in fully understanding the novel properties exhibited by nanocrystalline materials. The final microstructure of a material is dependent on the preparation method used, for example, sol-gel and ball-milling methods are commonly used in the preparation of nanocrystalline oxides. Additionally, there is a problem in maintaining the materials in nanocrystalline form when they are subjected to elevated temperatures. We have been exploring strategies to restrict the growth of nanocrystalline oxides and have found that adding a small amount of an inert material, e.g. SiO 2 or Al 2 O 3 , is particularly effective. We will report XRD and EXAFS studies of nanocrystalline ceria prepared by sol-gel, sol-gel pinned and ball-milling methods and the effect of preparation method on the final microstructure. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Effects of cadmium and mycorrhizal fungi on growth, fitness, and cadmium accumulation in flax (Linum usitatissimum; Linaceae).

Science.gov (United States)

Hancock, Laura M S; Ernst, Charlotte L; Charneskie, Rebecca; Ruane, Lauren G

2012-09-01

Agricultural soils have become contaminated with a variety of heavy metals, including cadmium. The degree to which soil contaminants affect plants may depend on symbiotic relationships between plant roots and soil microorganisms. We examined (1) whether mycorrhizal fungi counteract the potentially negative effects of cadmium on the growth and fitness of flax (Linum usitatissimum) and (2) whether mycorrhizal fungi affect the accumulation of cadmium within plant parts. Two flax cultivars (Linott and Omega) were grown in three soil cadmium environments (0, 5, and 15 ppm). Within each cadmium environment, plants were grown in either the presence or absence of mycorrhizal fungi. Upon senescence, we measured growth and fitness and quantified the concentration of cadmium within plants. Soil cadmium significantly decreased plant fitness, but did not affect plant growth. Mycorrhizal fungi, which were able to colonize roots of plants growing in all cadmium levels, significantly increased plant growth and fitness. Although mycorrhizal fungi counteracted the negative effects of cadmium on fruit and seed production, they also enhanced the concentration of cadmium within roots, fruits, and seeds. The degree to which soil cadmium affects plant fitness and the accumulation of cadmium within plants depended on the ability of plants to form symbiotic relationships with mycorrhizal fungi. The use of mycorrhizal fungi in contaminated agricultural soils may offset the negative effects of metals on the quantity of seeds produced, but exacerbate the accumulation of these metals in our food supply.

Photo catalytic degradation of nitrobenzene using nanocrystalline TiO{sub 2} photo catalyst doped with Zn ions

Energy Technology Data Exchange (ETDEWEB)

Reynoso S, E. A.; Perez S, S.; Reyes C, A. P.; Castro R, C. L.; Felix N, R. M.; Lin H, S. W. [Instituto Tecnologico de Tijuana, Centro de Graduados e Investigacion, Apdo. Postal 1166, 22000 Tijuana, Baja California (Mexico); Paraguay D, F. [Centro de Investigacion en Materiales Avanzados, Apdo. Postal 311109, Chihuahua (Mexico); Alonso N, G. [UNAM, Centro de Nanociencias y Nanotecnologia, Carretera Tijuana-Ensenada Km 107, Apdo. Postal 356, 22800 Ensenada, Baja California (Mexico)

2013-07-01

Photo catalysis is a method widely used in the degradation of organic pollutants of the environment. The development of new materials is very important to improve the photo catalytic properties and to find new applications for TiO{sub 2} as a photo catalyst. In this article we reported the synthesis of a photo catalyst based on TiO{sub 2} doped with Zn{sup 2+} ions highly efficient in the degradation of nitrobenzene. The results of photo catalytic activity experiments showed that the Zn{sup 2+} doped TiO{sub 2} is more active that un-doped TiO{sub 2} catalyst with an efficiency of 99% for the nitrobenzene degradation at 120 min with an apparent rate constant of 35 x 10{sup -3} min{sup -1}. For the characterization of photo catalyst X-ray diffraction, transmission electron microscopy and Raman spectroscopy were used. (Author)

Sputtered tungsten-based ternary and quaternary layers for nanocrystalline diamond deposition.

Science.gov (United States)

Walock, Michael J; Rahil, Issam; Zou, Yujiao; Imhoff, Luc; Catledge, Shane A; Nouveau, Corinne; Stanishevsky, Andrei V

2012-06-01

Many of today's demanding applications require thin-film coatings with high hardness, toughness, and thermal stability. In many cases, coating thickness in the range 2-20 microm and low surface roughness are required. Diamond films meet many of the stated requirements, but their crystalline nature leads to a high surface roughness. Nanocrystalline diamond offers a smoother surface, but significant surface modification of the substrate is necessary for successful nanocrystalline diamond deposition and adhesion. A hybrid hard and tough material may be required for either the desired applications, or as a basis for nanocrystalline diamond film growth. One possibility is a composite system based on carbides or nitrides. Many binary carbides and nitrides offer one or more mentioned properties. By combining these binary compounds in a ternary or quaternary nanocrystalline system, we can tailor the material for a desired combination of properties. Here, we describe the results on the structural and mechanical properties of the coating systems composed of tungsten-chromium-carbide and/or nitride. These WC-Cr-(N) coatings are deposited using magnetron sputtering. The growth of adherent nanocrystalline diamond films by microwave plasma chemical vapor deposition has been demonstrated on these coatings. The WC-Cr-(N) and WC-Cr-(N)-NCD coatings are characterized with atomic force microscopy and SEM, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and nanoindentation.

Nanocrystalline and ultrafine grain copper obtained by mechanical attrition

Directory of Open Access Journals (Sweden)

Rodolfo Rodríguez Baracaldo

2010-01-01

Full Text Available This article presents a method for the sample preparation and characterisation of bulk copper having grain size lower than 1 μm (ultra-fine grain and lower than 100 nm grain size (nanocrystalline. Copper is initially manufactured by a milling/alloying me- chanical method thereby obtaining a powder having a nanocrystalline structure which is then consolidated through a process of warm compaction at high pressure. Microstructural characterisation of bulk copper samples showed the evolution of grain size during all stages involved in obtaining it. The results led to determining the necessary conditions for achieving a wide range of grain sizes. Mechanical characterisation indicated an increase in microhardness to values of around 3.40 GPa for unconsolida- ted nanocrystalline powder. Compressivee strength was increased by reducing the grain size, thereby obtaining an elastic limit of 650 MPa for consolidated copper having a ~ 62 nm grain size.

Creep behavior of a nanocrystalline Fe-B-Si alloy

International Nuclear Information System (INIS)

Xiao, M.; Kong, Q.P.

1997-01-01

The research of nanocrystalline materials has attracted much attention in the world. In recent years, there have been several studies on their creep behavior. Among these, the authors have studied the tensile creep of a nanocrystalline Ni-P alloy (28 nm) at temperatures around 0.5 Tm (Tm is the melting point). The samples were prepared by the method of crystallization of amorphous ribbon. Based on the data of stress exponent and activation energy, they suggested that the creep was controlled by boundary diffusion; while the creep of the same alloy with a larger grain size (257 nm) was controlled by a different mechanism. In the present paper, the authors extend the research to the creep of a nanocrystalline Fe-B-Si alloy. The samples are also prepared by crystallization of amorphous ribbon. The samples such prepared have an advantage that the interfaces are naturally formed without artificial compaction and porosity

Microstructure characterization and cation distribution of nanocrystalline cobalt ferrite

International Nuclear Information System (INIS)

Abbas, Y.M.; Mansour, S.A.; Ibrahim, M.H.; Ali, Shehab E.

2011-01-01

Nanocrystalline cobalt ferrite has been synthesized using two different methods: ceramic and co-precipitation techniques. The nanocrystalline ferrite phase has been formed after 3 h of sintering at 1000 deg. C. The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction and the Rietveld method. The refinement result showed that the type of the cationic distribution over the tetrahedral and octahedral sites in the nanocrystalline lattice is partially an inverse spinel. The transmission electronic microscope analysis confirmed the X-ray results. The magnetic properties of the samples were characterized using a vibrating sample magnetometer. - Highlights: → The refinement result showed that the cationic distribution over the sites in the lattice is partially an inverse spinel. → The transmission electronic microscope analysis confirmed the X-ray results. → The magnetic properties of the samples were characterized using a vibrating sample magnetometer.

Strain rate sensitivity studies on bulk nanocrystalline aluminium by nanoindentation

Energy Technology Data Exchange (ETDEWEB)

Varam, Sreedevi; Rajulapati, Koteswararao V., E-mail: kvrse@uohyd.ernet.in; Bhanu Sankara Rao, K.

2014-02-05

Nanocrystalline aluminium powder synthesized using high energy ball milling process was characterized by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The studies indicated the powder having an average grain size of ∼42 nm. The consolidation of the powder was carried out by high-pressure compaction using a uni-axial press at room temperature by applying a pressure of 1.5 GPa. The cold compacted bulk sample having a density of ∼98% was subjected to nanoindentation which showed an average hardness and elastic modulus values of 1.67 ± 0.09 GPa and 83 ± 8 GPa respectively at a peak force of 8000 μN and a strain rate of 10{sup −2} s{sup −1}. Achieving good strength along with good ductility is challenging in nanocrystalline metals. When enough sample sizes are not available to measure ductility and other mechanical properties as per ASTM standards, as is the case with nanocrystalline materials, nanoindentation is a very promising technique to evaluate strain rate sensitivity. Strain rate sensitivity is a good measure of ductility and in the present work it is measured by performing indentation at various loads with varying loading rates. Strain rate sensitivity values of 0.024–0.054 are obtained for nanocrystalline Al which are high over conventional coarse grained Al. In addition, Scanning Probe Microscopy (SPM) image of the indent shows that there is some plastically flown region around the indent suggesting that this nanocrystalline aluminium is ductile.

Size-dependent deformation behavior of nanocrystalline graphene sheets

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhi [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Huang, Yuhong [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, Shaanxi (China); Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Sun, Yunjin [Faculty of Food Science and Engineering, Beijing University of Agriculture, Beijing Key Laboratory of Agricultural Product Detection and Control of Spoilage Organisms and Pesticide Residue, Beijing Laboratory of Food Quality and Safety, Beijing 102206 (China); Xu, Kewei, E-mail: kwxu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Department of Physics and Opt-electronic Engineering, Xi’an University of Arts and Science, Xi’an 710065, Shaanxi (China); Chu, Paul K., E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-08-15

Highlights: • MD simulation is conducted to study the deformation of nanocrystalline graphene. • Unexpectedly, the elastic modulus decreases with the grain size considerably. • But the fracture stress and strain are nearly insensitive to the grain size. • A composite model with grain domains and GBs as two components is suggested. - Abstract: Molecular dynamics (MD) simulation is conducted to study the deformation behavior of nanocrystalline graphene sheets. It is found that the graphene sheets have almost constant fracture stress and strain, but decreased elastic modulus with grain size. The results are different from the size-dependent strength observed in nanocrystalline metals. Structurally, the grain boundaries (GBs) become a principal component in two-dimensional materials with nano-grains and the bond length in GBs tends to be homogeneously distributed. This is almost the same for all the samples. Hence, the fracture stress and strain are almost size independent. As a low-elastic-modulus component, the GBs increase with reducing grain size and the elastic modulus decreases accordingly. A composite model is proposed to elucidate the deformation behavior.

Mechanochemical synthesis of nanocrystalline Fe and Fe–B magnetic alloys

Energy Technology Data Exchange (ETDEWEB)

Mohammadi, Majid; Ghasemi, Ali, E-mail: ali13912001@yahoo.com; Tavoosi, Majid

2016-12-01

Mechanochemical synthesis and magnetic characterization of nanocrystalline Fe and Fe–B magnetic alloys was the goal of this study. In this regard, different Fe{sub 2}O{sub 3}–B{sub 2}O{sub 3} powder mixtures with sufficient amount of CaH{sub 2} were milled in a planetary ball mill in order to produce nanocrystalline Fe, Fe{sub 95}B{sub 5} and Fe{sub 85}B{sub 15} alloys. The produced samples were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The results showed that, nanocrystalline Fe, Fe{sub 95}B{sub 5} and Fe{sub 85}B{sub 15} alloys can be successfully synthesized by the reduction reaction of Fe{sub 2}O{sub 3} and B{sub 2}O{sub 3} with CaH{sub 2} during mechanical alloying. The structure of produced Fe{sub 95}B{sub 5} and Fe{sub 85}B{sub 15} alloys was a combination of Fe and Fe{sub 2}B phases with average crystallite sizes of about 15 and 10 nm, respectively. The produced nanocrystalline alloys exhibited soft magnetic properties with the coercivity and saturation of magnetization in the range of 170–240 Oe and 9–28 emu/g, respectively. Increasing the boron content has a destructive effect on soft magnetic properties of Fe–B alloys. - Highlights: • We study the mechanochemical synthesis of nanocrystalline boron, Fe and Fe–B alloys. • We study the reduction reaction of B{sub 2}O{sub 3}–CaH{sub 2} during milling. • We study the reduction reaction of Fe{sub 2}O{sub 3}–CaH{sub 2} during milling. • We study the reduction reaction of Fe{sub 2}O{sub 3}–B{sub 2}O{sub 3}–CaH{sub 2} during milling. • We study the effect of B on magnetic properties of nanocrystalline Fe–B alloys.

Microporous MOFs Engaged in the Formation of Nitrogen-Doped Mesoporous Carbon Nanosheets for High-Rate Supercapacitors.

Science.gov (United States)

Hou, Ya-Nan; Zhao, Zongbin; Yu, Zhengfa; Zhang, Su; Li, Shaofeng; Yang, Juan; Zhang, Han; Liu, Chang; Wang, Zhiyu; Qiu, Jieshan

2018-02-21

Nitrogen-doped mesoporous carbon nanosheets (NMCS) have been fabricated from zinc-based microporous metal-organic frameworks (ZIF-8) by pyrolysis in a molten salt medium. The as-prepared NMCS exhibit significantly improved specific capacitance (NMCS-8: 232 F g -1 at 0.5 A g -1 ) and capacitance retention ratio (75.9 % at 50 A g -1 ) compared with the micropore-dominant nitrogen-doped porous carbon polyhedrons (NPCP-5: 178 F g -1 at 0.5 A g -1 , 15.9 % at 20 A g -1 ) obtained by direct pyrolysis of nanocrystalline ZIF-8. The excellent capacitive performance and high rate performance of the NMCS can be attributed to their unique combination of structure and composition, that is, the two-dimensional and hierarchically porous structure provides a short ion-transport pathway and facilitates the supply of electrolyte ions, and the nitrogen-doped polar surface improves the interface wettability when used as an electrode. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rare-earth doped gadolinia based phosphors for potential multicolor and white light emitting deep UV LEDs.

Science.gov (United States)

Bedekar, Vinila; Dutta, Dimple P; Mohapatra, M; Godbole, S V; Ghildiyal, R; Tyagi, A K

2009-03-25

Gadolinium oxide host and europium/dysprosium/terbium doped gadolinium oxide nanoparticles were synthesized using the sonochemical technique. Gadolinium oxide nanocrystals were also co-doped with total 2 mol% of Eu(3+)/Dy(3+),Eu(3+)/Tb(3+),Dy(3+)/Tb(3+), and also Eu(3+)/Dy(3+)/Tb(3+) ions, by the same method. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) techniques. The size of the particles ranged from 15 to 30 nm. The triple doped samples showed multicolor emission on single wavelength excitation. The photoluminescence results were correlated with the lifetime data to get an insight into the luminescence and energy transfer processes taking place in the system. On excitation at 247 nm, the novel nanocrystalline Gd(2)O(3):RE (RE = Dy, Tb) phosphor resulted in having very impressive CIE chromaticity coordinates of x = 0.315 and y = 0.316, and a correlated color temperature of 6508 K, which is very close to standard daylight.

Cadmium Alternatives

Science.gov (United States)

2012-08-01

carcinogenic, leachable Trivalent and non- chrome passivates generally struggle with conductivity Major Differences in Trivalent vs. Hexavalent Passivates...for Change Cadmium passivated with hexavalent chromium has been in use for many decades Cadmium is toxic, and is classified as a priority...Executive Orders 13514 & 13423 DoD initiatives – Young memo (April 2009) DFAR restricting use of hexavalent chromium Allows the use of hexavalent

Investigation of microstructure thermal evolution in nanocrystalline Cu

International Nuclear Information System (INIS)

Zhou Kai; Li Hui; Pang Jinbiao; Wang Zhu

2011-01-01

The microstructure of nanocrystalline Cu prepared by compacting nanoparticles (50-60 nm in diameter) under high pressures has been studied by means of positron lifetime spectroscopy and X-ray diffraction. These nanoparticles were produced by two different methods. We found that there are order regions interior to the grains and disorder regions at the grain boundaries with a wide distribution of interatomic distances. The mean grain sizes of the nanocrystalline Cu samples decrease after being annealed at 900 o C and increase during aging at 180 o C, which are observed by X-ray diffraction, revealing that the atoms exchange between the two regions. The positron lifetime results clearly indicate that the vacancy clusters formed in the annealing process are unstable and decomposed at the aging time below 6 hours. In addition, the partially oxidized surfaces of the nanoparticles hinder grain growth when the samples age at 180 o C, and the vacancy clusters inside the disorder regions, which are related to Cu 2 O, need longer aging time to decompose. The disorder regions remain after the heat treatment in this work, in spite of the grain growth, which will be good for the samples keeping the properties of nanocrystalline material. -- Research highlights: → We use a digital positron lifetime spectrometer correlated with XRD to study the microstructure evolution of nanocrystalline Cu during thermal treatment. → An atomic scale microstructure of grain boundary is characterized. Further, the surface oxidation of the nanoparticles is considered. → The disorder regions remain after the heat treatment in this work, in spite of grain growth.

Critical currents and fields of disordered nanocrystalline superconductors

International Nuclear Information System (INIS)

Yavary, H.; Shahzamanian, M.A.; Rabbani, H.

2007-01-01

Full text: There is an enormous effort directed at increasing the upper critical field of the superconducting materials because this upper critical field provides a fundamental limit to the maximum field a magnet system can produce. High-energy particle accelerators and medical resonance imaging body scanners are limited by the for NbTi (10 T). Gigahertz class nuclear-magnetic-resonance and high field laboratory magnets are limited by for Nb 3 Sn (23 T) [1]. However, the values of critical current density are too low for industrial use, possibly because of degraded or nonsuperconducting phases, such as MoS 2 or Mo 2 S 3 , at the grain boundaries or because the pinning site density is not high enough. It has long been known that decreasing the grain size of low-temperature superconducting (LTS) materials, such as Nb 3 Sn, increases the density of flux pinning sites and hence. Nanocrystalline materials are characterized by ultrafine grains and a high density of grain boundaries [2]. Hence nanocrystalline materials can exhibit unusual physical, chemical, and mechanical properties with respect to conventional polycrystalline materials. The purpose of this paper is to investigate the structure of currents and fields in disordered nanocrystalline superconducting materials by the use of quasiclassical many body techniques. The Keldish Greens functions are used to calculate the current density of the system. Since the disorder and microstructure of these nanocrystalline materials are on a sufficiently short length scale as to increase both the density of pinning site and the upper critical field. (authors)

Ultrafast Terahertz Conductivity of Photoexcited Nanocrystalline Silicon

DEFF Research Database (Denmark)

Cooke, David; MacDonald, A. Nicole; Hryciw, Aaron

2007-01-01

The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described by a class...... in the silicon nanocrystal films is dominated by trapping at the Si/SiO2 interface states, occurring on a 1–100 ps time scale depending on particle size and hydrogen passivation......The ultrafast transient ac conductivity of nanocrystalline silicon films is investigated using time-resolved terahertz spectroscopy. While epitaxial silicon on sapphire exhibits a free carrier Drude response, silicon nanocrystals embedded in glass show a response that is best described...

Effect of doping on all TMC vertical heterointerfaces

Science.gov (United States)

Nair, Salil; Joy, Jolly; Patel, K. D.; Pataniya, Pratik; Solanki, G. K.; Pathak, V. M.; Sumesh, C. K.

2018-05-01

The present work reports the growth and basic characterizations of GeSePbx (x=0, 0.02, 0.04) layered mono chalcogenide single crystal substrates for preparation of heterojunction devices. These crystals are grown by Direct Vapour Transport (DVT) Technique [1,2]. Heterojunction interfaces on these substrates are prepared using thermal evaporation of nanocrystalline SnSe thin films having 5kÅ thickness. The electrical characterizations reveal the rectifying behavior of the devices based on which its ideality factor, barrier height, saturation current, series resistance etc. have been determined using thermionic emission model [3,4]. The device parameters have been determined and analyzed by three different methods viz. LnI-V, Cheung's method and Norde method [5]. The variation in the device parameters in light of doping is reported in the present work.

Method of mechanochemical synthesis for the production of nanocrystalline Nb-Al alloys

International Nuclear Information System (INIS)

Portnoj, V.K.; Tret'yakov, K.V.; Logacheva, A.I.; Logunov, A.V.; Razumovskij, I.M.

2004-01-01

Using X-ray diffraction and DS analyses the process of solid phase synthesis on cooperative comminution of components (Nb, Al, Cr) in a planetary ball mill is investigated. Powder nanocrystalline Nb 3 Al base alloys of various compositions with simultaneous introduction of chromium are synthesized. High power milling results in block size of ∼ 20 nm. It is shown that final chromium dissolution and partial decomposition of Nb(Al) supersaturated solid solutions proceed after heating up to 1100 deg C only. With the help of doping with niobium by the method of mechanical alloying, a two-phase alloy Nb 3 Al + Nb 2 Al having been produced by arc melting, is corrected by composition and transferred to the two-phase region of Nb 3 Al + Nb(Al). It is revealed that the process of niobium aluminide phase formation during mechanochemical synthesis and the process of mechanical activation of Nb-Al system intermetallics enriched with niobium always proceed through formation of supersaturated solid solutions. The mechanism of the process is probably associated with stacking faults formation due to deformation [ru

Cadmium exposure in the Swedish environment

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

This report gives a thorough description of cadmium in the Swedish environment. It comprises three parts: Cadmium in Sweden - environmental risks;, Cadmium in goods - contribution to environmental exposure;, and Cadmium in fertilizers, soil, crops and foods - the Swedish situation. Separate abstracts have been prepared for all three parts

Transformation of Goethite to Hematite Nanocrystallines by High Energy Ball Milling

Directory of Open Access Journals (Sweden)

O. M. Lemine

2014-01-01

Full Text Available α-Fe2O3 nanocrystallines were prepared by direct transformation via high energy ball milling treatment for α-FeOOH powder. X-ray diffraction, Rietveld analysis, TEM, and vibrating sample magnetometer (VSM are used to characterize the samples obtained after several milling times. Phase identification using Rietveld analysis showed that the goethite is transformed to hematite nanocrystalline after 40 hours of milling. HRTEM confirm that the obtained phase is mostly a single-crystal structure. This result suggested that the mechanochemical reaction is an efficient way to prepare some iron oxides nanocrystallines from raw materials which are abundant in the nature. The mechanism of the formation of hematite is discussed in text.

A comparative study of humidity sensing and photocatalytic applications of pure and nickel (Ni)-doped WO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Ramkumar, S. [Bannari Amman Institute of Technology, Department of Physics, Erode, Tamilnadu (India); Rajarajan, G. [Vidhya Mandhir Institute of Technology, Department of Physics, Erode, Tamilnadu (India)

2017-06-15

Nanocrystalline of pristine and nickel (Ni)-doped tungsten trioxide (WO{sub 3}) thin films was deposited by chemical bath deposition method. The concentrations of Ni ions were varied from 0 to 10 wt%. In order to improve the crystallinity of the films were annealed at 600 C for 2 h in the ambient atmosphere. X-ray diffraction results reveal that the WO{sub 3} doped with nickel crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0951). AFM micrographs reveal that average grain size of about 27-39 nm for pure and Ni-doped WO{sub 3} thin films. In addition, the band gap of the Ni-doped WO{sub 3} nanostructures is facilely tunable by controlling the Ni contents. The humidity sensor setup was fabricated and measured for pure and Ni-doped WO{sub 3} thin film sensor with various level of RH (10-90%). The Ni-doped WO{sub 3} sensor showed fast response and high sensitivity than pure WO{sub 3}. The photocatalytic activities of the films were evaluated by degradation of methyl orange, methylene blue and phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of WO{sub 3} nanostructures could be remarkably enhanced by doping the Ni impurity. (orig.)

Effects of Different Dietary Cadmium Levels on Growth and Tissue Cadmium Content in Juvenile Parrotfish,

Directory of Open Access Journals (Sweden)

Okorie E. Okorie

2014-01-01

Full Text Available This feeding trial was carried out to evaluate the effects of different dietary cadmium levels on growth and tissue cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using cadmium chloride (CdCl2 as the cadmium source. Fifteen fish averaging 5.5±0.06 g (mean±SD were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 (C0, 21.0 (C21, 40.7 (C41, 83.5 (C83, 162 (C162, 1,387 (C1,387 and 2,743 (C2,743 mg cadmium/kg diet. At the end of sixteen weeks of feeding trial, weight gain (WG, specific growth rate (SGR and feed efficiency (FE of fish fed C21 were significantly higher than those of fish fed C83, C162, C1,387 and C2,743 (p<0.05. Weight gain, SGR and FE of fish fed C0, C21 and C41 were significantly higher than those of fish fed C162, C1,387 and C2,743. Protein efficiency ratio of fish fed C0, C21 and C41 were significantly higher than those of fish fed C1,387 and C2,743. Average survival of fish fed C0, C21, C41 and C162 were significantly higher than that of fish fed C2,743. Tissue cadmium concentrations increased with cadmium content of diets. Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver cadmium concentrations of fish fed C0, C21, C41 and C83 were significantly lower than those of fish fed C162, C1,387 and C2,743. Based on the ANOVA results of growth performance and tissue cadmium concentrations the safe dietary cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet.

Hot pressing of nanocrystalline tantalum using high frequency induction heating and pulse plasma sintering

Science.gov (United States)

Jakubowicz, J.; Adamek, G.; Sopata, M.; Koper, J. K.; Siwak, P.

2017-12-01

The paper presents the results of nanocrystalline powder tantalum consolidation using hot pressing. The authors used two different heating techniques during hot pressing: high-frequency induction heating (HFIH) and pulse plasma sintering (PPS). A comparison of the structure, microstructure, mechanical properties and corrosion resistance of the bulk nanocrystalline tantalum obtained in both techniques was performed. The nanocrystalline powder was made to start from the microcrystalline one using the high-energy ball milling process. The nanocrystalline powder was hot-pressed at 1000 °C, whereas, for comparison, the microcrystalline powder was hot pressed up to 1500 °C for proper consolidation. The authors found that during hot pressing, the powder partially reacts with the graphite die covered by boron nitride, which facilitated punches and powder displacement in the die during densification. Tantalum carbide and boride in the nanocrystalline material was found, which can improve the mechanical properties. The hardness of the HFIH and PPS nanocrystalline tantalum was as high as 625 and 615 HV, respectively. The microstructure was more uniform in the PPS nanomaterial. The corrosion resistance in both cases deteriorated, in comparison to the microcrystalline material, while the PPS material corrosion resistance was slightly better than that of the HFIH one.

Cadmium plating replacements

Energy Technology Data Exchange (ETDEWEB)

Nelson, M.J.; Groshart, E.C.

1995-03-01

The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

Defects and properties of cadmium oxide based transparent conductors

International Nuclear Information System (INIS)

Yu, Kin Man; Detert, D. M.; Dubon, O. D.; Chen, Guibin; Zhu, Wei; Liu, Chaoping; Grankowska, S.; Hsu, L.; Walukiewicz, Wladek

2016-01-01

Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10 20 /cm 3 and mobility in the range of 40–100 cm 2 /V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O 2 partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10 −4 to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10 21  cm −3 and electron mobility higher than 120 cm 2 /V s can be achieved. Thermal annealing of doped CdO films in N 2 ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited by a background acceptor concentration of

Defects and properties of cadmium oxide based transparent conductors

Energy Technology Data Exchange (ETDEWEB)

Yu, Kin Man, E-mail: kinmanyu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Detert, D. M.; Dubon, O. D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Chen, Guibin [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department and Jiangsu Key Laboratory for Chemistry of Low Dimensional Materials, Huaiyin Normal University, Jiangsu 223300 (China); Zhu, Wei [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics and The Center for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026 (China); Liu, Chaoping [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Grankowska, S. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Experimental Physics (IEP UW), Warsaw University, Warsaw (Poland); Hsu, L. [Department of Postsecondary Teaching and Learning, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Walukiewicz, Wladek [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2016-05-14

Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10{sup 20}/cm{sup 3} and mobility in the range of 40–100 cm{sup 2}/V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O{sub 2} partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10{sup −4} to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10{sup 21 }cm{sup −3} and electron mobility higher than 120 cm{sup 2}/V s can be achieved. Thermal annealing of doped CdO films in N{sub 2} ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited

Texture-dependent twin formation in nanocrystalline thin Pd films

International Nuclear Information System (INIS)

Wang, B.; Idrissi, H.; Shi, H.; Colla, M.S.; Michotte, S.; Raskin, J.P.; Pardoen, T.; Schryvers, D.

2012-01-01

Nanocrystalline Pd films were produced by electron-beam evaporation and sputter deposition. The electron-beam-evaporated films reveal randomly oriented nanograins with a relatively high density of growth twins, unexpected in view of the high stacking fault energy of Pd. In contrast, sputter-deposited films show a clear 〈1 1 1〉 crystallographic textured nanostructure without twins. These results provide insightful information to guide the generation of microstructures with enhanced strength/ductility balance in high stacking fault energy nanocrystalline metallic thin films.

Topological characterization of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites

Science.gov (United States)

Bhat, A. H.; Dasan, Y. K.; Khan, Ihsan Ullah; Ahmad, Faiz; Ayoub, Muhammad

2016-11-01

This study was conducted to evaluate the morphological and barrier properties of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites. Nanocrystalline cellulose was isolated from waste oil palm empty fruit bunch fiber using Sulphuric acid hydrolysis. Chemical modifications of nanocrystalline cellulose was performed to allow good compatibilization between fiber and the polymer matrices and also to improve dispersion of fillers. Bionanocomposite materials were produced from these nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) using solvent casting and evaporation techniques. The properties of extracted nanocrystalline cellulose were examined using FT-IR spectroscopy, X-ray diffractometer, TEM and AFM. Besides that, the properties of bionanocomposites were examined through FESEM and oxygen permeability properties analysis. Better barrier and morphological properties were obtained for nanocrystalline cellulose reinforced bionanocomposites than for neat polymer blend.

Mechanisms of cadmium induced genomic instability

Energy Technology Data Exchange (ETDEWEB)

Filipic, Metka, E-mail: metka.filipic@nib.si [National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, Ljubljana (Slovenia)

2012-05-01

Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

Mechanisms of cadmium induced genomic instability

International Nuclear Information System (INIS)

Filipič, Metka

2012-01-01

Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

Structural, optical and photovoltaic properties of P3HT and Mn-doped CdS quantum dots based bulk hetrojunction hybrid layers

Science.gov (United States)

Jabeen, Uzma; Adhikari, Tham; Pathak, Dinesh; Shah, Syed Mujtaba; Nunzi, Jean-Michel

2018-04-01

Cadmium sulphide (CdS) and Mn-doped CdS nanocrystals were synthesized by co-precipitation method. The nanocrystals were characterized by Fluorescence, Fourier Transformed Infra-red Spectrometer (FTIR), UV-Visible, X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), Field Emission Scanning Electron Microscope (FESEM), and High Resolution Transmission Electron Microscope (HRTEM). A considerable blue shift of absorption band with respect to the cadmium sulphide was observed by the Mn concentration (0.5 M) in the doped sample with decreasing the size of nanocrystals. Other reason for this may be Mn doping. Subsequently the band gap was altered from 2.11 to 2.21 eV due to quantum confinement effect. Scanning electron microscope supplemented with EDAX was operated to find grain size and chemical composition of the synthesized nanomaterials. The PL spectrum of Mn-doped CdS nanocrystals displays three PL bands the first one, within the range of 500 nm and the second band at 537 nm, and the third one around 713 nm is labelled red band emission due to attributed to a 4T1→6A1 transition within the 3d shell of divalent manganese. XRD analysis showed that the material was in cubic crystalline state. A comparative study of surfaces of un-doped and metal doped CdS nanocrystals were investigated using X-ray Photoelectron Spectroscopy (XPS). The synthesized nanomaterial in combination with polymer, poly (3-hexyl thiophene) was operated in the construction of photovoltaic cells. The photovoltaic devices with CdS nanocrystals exhibited power conversion efficiency of 0.34% without annealing and 0.38% with annealing. However, the power conversion efficiency was enhanced by a factor of 0.35 without annealing and 0.42 with annealing with corporation of Mn impurity in CdS lattice. Atomic Force Microscopy was employed for morphology and packing behavior of blend of nanocrystals with organic polymer.

Electrodeposition and characterization of nanocrystalline CoNiFe films

Energy Technology Data Exchange (ETDEWEB)

Chen, Y.; Wang, Q.P. [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Cai, C. [School of Chemistry and chemical engineering, Ningxia University, Yinchuan 750021 (China); Yuan, Y.N. [Department of Materials and Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Cao, F.H. [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang, Z., E-mail: eaglezzy@zjuem.zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang, J.Q. [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); State Key Laboratory for Corrosion and Protection of Metals, Shenyang 110016 (China)

2012-02-29

Nanocrystalline Co{sub 45}Ni{sub 10}Fe{sub 24} films have been fabricated using cyclic voltammetry technique from the solutions containing sulfate, then characterized by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometer. Meanwhile, Electrochemical Impedance Spectroscopy technique has been employed to probe into the nucleation/growth behavior of Co{sub 45}Ni{sub 10}Fe{sub 24} films. The results show that, the obtained Co{sub 45}Ni{sub 10}Fe{sub 24} film possesses low coercivity of 973.3 A/m and high saturation magnetic flux density of 1.59 Multiplication-Sign 10{sup 5} A/m. Under the experimental conditions, the nucleation/growth process of Co{sub 45}Ni{sub 10}Fe{sub 24} films is mainly under activation control. With the increase of the applied cathodic potential bias, the charge transfer resistance for CoNiFe deposition decreases exponentially. - Highlights: Black-Right-Pointing-Pointer Nanocrystalline Co{sub 45}Ni{sub 10}Fe{sub 24} film is obtained using cyclic voltammetry technique. Black-Right-Pointing-Pointer Nanocrystalline Co{sub 45}Ni{sub 10}Fe{sub 24} possesses low coercivity of 973.3 A/m. Black-Right-Pointing-Pointer Nanocrystalline Co{sub 45}Ni{sub 10}Fe{sub 24} possesses high saturation magnetic flux density. Black-Right-Pointing-Pointer The nucleation/growth process of CoNiFe films is mainly under activation control. Black-Right-Pointing-Pointer The charge transfer resistance for CoNiFe deposition decreases exponentially.

Radiation influence on properties of nanocrystalline alloy

International Nuclear Information System (INIS)

Holkova, D.; Sitek, J.; Novak, P.; Dekan, J.

2016-01-01

Our work is focused on the studied of structural changes amorphous and nanocrystalline alloys after irradiation with electrons. For the analysis of these alloy we use two spectroscopic methods: Moessbauer spectroscopy and XRD. Measurements of nanocrystalline (Fe 3 Ni 1 ) 81 Nb 7 B 12 samples before and after electrons irradiation by means of Moessbauer spectroscopy and XRD showed that the electrons causes changes in magnetic structure which is reflected changes of direction of net magnetic moment. Structural changes occurs in the frame of error indicated by both spectroscopic methods. We can confirm that this kind alloys a resistive again electrons irradiation up to doses of 4 MGy. We observed in this frame only beginning of the radiation damage. (authors)

A computation model for the corrosion resistance of nanocrystalline zirconium metal

International Nuclear Information System (INIS)

Zhang Xiyan; Shi Minghua; Liu Nianfu; Wei Yiming; Li Cong; Qiu Shaoyu; Zhang Qiang; Zhang Pengcheng

2007-01-01

In this paper a computation model of corrosion rate-grain size of nanocrystalline and ultra-fine zirconium has been presented. The model is based on the Wagner's theory and the electron theory of solids. The conductivity, electronic mean free path and grain size of metal were considered. By this model, the corrosion rate of zirconium metal under different temperature was computed. The results show that the corrosion weight gain and rate constant of nanocrystalline zirconium is lower than that of zirconium with coarse grain size. And the corrosion rate constant and weight gain of nanocrystalline zirconium metal decrease with the decrease of grain size. So the refinement of grain size can remarkably improve the corrosion resistance of zirconium metal. (authors)

Coexistence of short- and long-range ferromagnetic order in nanocrystalline Fe2Mn1−xCuxAl (x=0.0, 0.1 and 0.3) synthesized by high-energy ball milling

International Nuclear Information System (INIS)

Thanh, Tran Dang; Nanto, Dwi; Tuyen, Ngo Thi Uyen; Nan, Wen-Zhe; Yu, YiKyung; Tartakovsky, Daniel M.; Yu, S.C.

2015-01-01

In this work, we prepared nanocrystalline Fe 2 Mn 1−x Cu x Al (x=0.0, 0.1 and 0.3) powders by the high energy ball milling technique, and then studied their critical properties. Our analysis reveals that the increase of Cu-doping concentration (up to x=0.3) in these powders leads to a gradual increase of the ferromagnetic–paramagnetic transition temperature from 406 to 452 K. The Banerjee criterion suggests that all the samples considered undergo a second-order phase transition. A modified Arrott plot and scaling analysis indicate that the critical exponents (β=0.419 and 0.442, γ=1.082 and 1.116 for x=0.0 and 0.1, respectively) are located in between those expected for the 3D-Heisenberg and the mean-field models; the values of β=0.495 and γ=1.046 for x=0.3 sample are very close to those of the mean-field model. These features reveal the coexistence of the short- and long-range ferromagnetic order in the nanocrystalline Fe 2 Mn 1−x Cu x Al powders. Particularly, as the concentration of Cu increases, values of the critical exponent shift towards those of the mean-field model. Such results prove the Cu doping favors establishing a long-range ferromagnetic order. - Highlights: • Fe 2 Mn 1−x Cu x Al nanocrystals were prepared by a high energy ball milling method. • A coexistence of the short- and long-range FM order in the nanocrystals. • Cu doping favors establishing a long-range FM order in the nanocrystals. • All the ΔS m (T, H) data are followed a universal master curve

Rare earths (Ce, Eu, Tb) doped Y2Si2O7 phosphors for white LED

International Nuclear Information System (INIS)

Sokolnicki, Jerzy

2013-01-01

Nanocrystalline yttrium pyrosilicate Y 2 Si 2 O 7 (YPS) singly, doubly or triply doped with Ce 3+ , Eu 3+ , Tb 3+ was obtained by the reaction of nanostructured Y 2 O 3 :Ln 3+ and colloidal SiO 2 at high temperatures. X-ray diffraction analysis confirmed the formation of a single phase of α-YPS at 1200 °C. Two series of YPS samples doped with Eu 3+ or Eu 3+ /Tb 3+ were obtained by applying the reducing atmosphere (75%N 2 +25%H 2 ) at different temperatures. The luminescence and excitation spectra are reported. The singly Eu 3+ doped YPS emit from both Eu 3+ and Eu 2+ ions, with the spectral position and width of the Eu 2+ emission different in both series. The presence of Eu 2+ in the samples was confirmed by electron paramagnetic resonance (EPR) spectra. A broadband emission of Eu 2+ (380–650 nm), combined with the red emission of Eu 3+ is perceived by the naked eye as white light. Co-doping of YPS:Eu 3+ with Tb 3+ results in enhancement of the green component of the emission, and well-balanced white luminescence. The colour of this emission is tunable, and it is possible to get Commission International de I'Eclairage (CIE) chromaticity coordinates of (0.327, 0.327), colour-rendering index (CRI) of 85, and quantum efficiency (QE) of 71%. These phosphors are efficiently excited in the wavelength range of 300–420 nm, which perfectly matches a near UV-emitting InGaN chip. It was shown that for triply (Ce 3+ , Eu 3+ and Tb 3+ ) doped samples the three emissions from the particular activators can be generated using one excitation wavelength. The white light resulting from the superposition of the blue (Ce 3+ ), green (Tb 3+ ) and red (Eu 3+ ) emissions can be obtained by varying the concentration of the active ions and the treating atmosphere, i.e. reducing or oxidising. Eu 2+ was not detected in the triply doped samples, and hence line emissions mostly exhibit CRI values equal to or below 30. - Highlights: ► Nanocrystalline Y 2 Si 2 O 7 was obtained by the

High-pressure X-ray diffraction study of bulk- and nanocrystalline GaN

DEFF Research Database (Denmark)

Jorgensen, J.E.; Jakobsen, J.M.; Jiang, Jianzhong

2003-01-01

Bulk- and nanocrystalline GaN have been studied by high-pressure energy-dispersive X-ray diffraction. Pressure-induced structural phase transitions from the wurtzite to the NaCl phase were observed in both materials. The transition pressure was found to be 40 GPa for the bulk-crystalline GaN, while...... the wurtzite phase was retained up to 60 GPa in the case of nanocrystalline GaN. The bulk moduli for the wurtzite phases were determined to be 187 ( 7) and 319 ( 10) GPa for the bulk- and nanocrystalline phases, respectively, while the respective NaCl phases were found to have very similar bulk moduli [ 208...

Cadmium in the biofuel system

International Nuclear Information System (INIS)

Aabyhammar, T.; Fahlin, M.; Holmroos, S.

1993-12-01

Removal of biofuel depletes the soil of important nutrients. Investigations are being made of possibilities to return most of these nutrients by spreading the ashes remaining after combustion in the forest or on field. Return of ashes implies that both beneficial and harmful substances are returned. This study has been conducted to illustrate that the return of cadmium implies the greatest risk for negative influences. The occurrence, utilization, emissions and effects of cadmium are discussed. The behaviour of cadmium in soil is discussed in detail. Flows and quantities of cadmium in Swedish society are reviewed. Flows and quantities of both total and plant available cadmium in the entire forest and arable areas of Sweden are given. A scenario for a bioenergy system of max 100 TWh is discussed. The cadmium flow in different biofuels and forest raw products, and anticipated amounts of ashes and cadmium concentrations, are calculated. Power production from biofuels is surveyed. Possibilities to clean ashes have been examined in laboratory experiments. Ashes and trace elements occurring as a result of the gasification of biofuels are reviewed. Strategies for handling ashes are discussed. Proposals on continued inputs in both the biological and technical sciences are made. 146 refs, 23 figs, 38 tabs

Research Update: Phonon engineering of nanocrystalline silicon thermoelectrics

Directory of Open Access Journals (Sweden)

Junichiro Shiomi

2016-10-01

Full Text Available Nanocrystalline silicon thermoelectrics can be a solution to improve the cost-effectiveness of thermoelectric technology from both material and integration viewpoints. While their figure-of-merit is still developing, recent advances in theoretical/numerical calculations, property measurements, and structural synthesis/fabrication have opened up possibilities to develop the materials based on fundamental physics of phonon transport. Here, this is demonstrated by reviewing a series of works on nanocrystalline silicon materials using calculations of multiscale phonon transport, measurements of interfacial heat conduction, and synthesis from nanoparticles. Integration of these approaches allows us to engineer phonon transport to improve the thermoelectric performance by introducing local silicon-oxide structures.

Solvothermal synthesis of nanorods of ZnO, N-doped ZnO and CdO

International Nuclear Information System (INIS)

Varghese, Neenu; Panchakarla, L.S.; Hanapi, M.; Govindaraj, A.; Rao, C.N.R.

2007-01-01

ZnO nanorods with diameters in the 80-800 nm range are readily synthesized by the reaction of zinc acetate, ethanol and ethylenediamine under solvothermal conditions. The best products are obtained at 330 deg. C with a slow heating rate. Addition of the surfactant Triton -X 100 gave nanorods of uniform (300 nm) diameter. By adding a small amount of liquid NH 3 to the reaction mixture, N-doped ZnO nanorods, with distinct spectroscopic features are obtained. CdO nanorods of 80 nm diameter have been prepared under solvothermal conditions using a mixture of cadmium cupferronate, ethylenediamine and ethanol at 330 deg. C. Similarly, Zn 1-x Cd x O nanorods of a 70 nm diameter are obtained under solvothermal conditions starting with a mixture of zinc acetate, cadmium cupferronate, ethanol and ethylenediamine

Uptake and distribution of cadmium in corn

International Nuclear Information System (INIS)

Peel, J.W.; Vetter, R.J.; Christian, J.E.; Kessler, W.V.; McFee, W.W.

1978-01-01

The uptake and distribution of cadmium in corn (Zea mays) treated at various time intervals after planting and sampled at various times after treatment were measured. Cadmium was found to accumulate in all parts sampled. As shown in field studies, stems and leaves generally concentrated more cadmium than did husks, cobs, kernels, silks, or tassels. Samples of stems and leaves from corn treated 23 days after planting and sampled 5 days later exhibited higher concentrations of cadmium than samples taken 25, 45, 65, or 85 days after treatment. Concentrations generally decreased with time. Greenhouse studies showed that corn exposed to cadmium for the longest period of time accumulated the greatest total cadmium. The highest cadmium concentrations were found in the base or lowest leaves sampled 45 days after planting; this suggests a useful technique for quick screening corn crops for cadmium pollution

Separation of intra- and intergranular magnetotransport properties in nanocrystalline diamond films on the metallic side of the metal-insulator transition

International Nuclear Information System (INIS)

Janssens, S D; Pobedinskas, P; Ruttens, B; D'Haen, J; Nesladek, M; Haenen, K; Wagner, P; Vacik, J; Petrakova, V

2011-01-01

A systematic study on the morphology and electronic properties of thin heavily boron-doped nanocrystalline diamond (NCD) films is presented. The films have nominally the same thickness (∼150 nm) and are grown with a fixed B/C ratio (5000 ppm) but with different C/H ratios (0.5-5%) in the gas phase. The morphology of the films is investigated by x-ray diffraction and atomic force microscopy measurements, which confirm that lower C/H ratios lead to a larger average grain size. Magnetotransport measurements reveal a decrease in resistivity and a large increase in mobility, approaching the values obtained for single-crystal diamond as the average grain size of the films increases. In all films, the temperature dependence of resistivity decreases with larger grains and the charge carrier density and mobility are thermally activated. It is possible to separate the intra- and intergrain contributions for resistivity and mobility, which indicates that in these complex systems Matthiessen's rule is followed. The concentration of active charge carriers is reduced when the boron-doped NCD is grown with a lower C/H ratio. This is due to lower boron incorporation, which is confirmed by neutron depth profiling.

Biological indicators of cadmium exposure and toxicity

Energy Technology Data Exchange (ETDEWEB)

Shaikh, Z A; Smith, L M

1986-01-01

The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatine, beta 2-microglobulin, alpha 1-anti-trypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose, beta 2-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and beta 2-microglubulin may be used together to assess cadmium exposure and toxicity. 66 references.

Effect of p-layer properties on nanocrystalline absorber layer and thin film silicon solar cells

International Nuclear Information System (INIS)

Chowdhury, Amartya; Adhikary, Koel; Mukhopadhyay, Sumita; Ray, Swati

2008-01-01

The influence of the p-layer on the crystallinity of the absorber layer and nanocrystalline silicon thin film solar cells has been studied. Boron doped Si : H p-layers of different crystallinities have been prepared under different power pressure conditions using the plasma enhanced chemical vapour deposition method. The crystalline volume fraction of p-layers increases with the increase in deposition power. Optical absorption of the p-layer reduces as the crystalline volume fraction increases. Structural studies at the p/i interface have been done by Raman scattering studies. The crystalline volume fraction of the i-layer increases as that of the p-layer increases, the effect being more prominent near the p/i interface. Grain sizes of the absorber layer decrease from 9.2 to 7.2 nm and the density of crystallites increases as the crystalline volume fraction of the p-layer increases and its grain size decreases. With increasing crystalline volume fraction of the p-layer solar cell efficiency increases

The effect of annealing on structural, optical and photosensitive properties of electrodeposited cadmium selenide thin films

Directory of Open Access Journals (Sweden)

Somnath Mahato

2017-06-01

Full Text Available Cadmium selenide (CdSe thin films have been deposited on indium tin oxide coated glass substrate by simple electrodeposition method. X-ray Diffraction (XRD studies identify that the as-deposited CdSe films are highly oriented to [002] direction and they belong to nanocrystalline hexagonal phase. The films are changed to polycrystalline structure after annealing in air for temperatures up to 450 °C and begin to degrade afterwards with the occurrence of oxidation and porosity. CdSe completely ceases to exist at higher annealing temperatures. CdSe films exhibit a maximum absorbance in the violet to blue-green region of an optical spectrum. The absorbance increases while the band gap decreases with increasing annealing temperature. Surface morphology also shows that the increase of the annealing temperature caused the grain growth. In addition, a number of distinct crystals is formed on top of the film surface. Electrical characteristics show that the films are photosensitive with a maximum sensitivity at 350 °C.

Microstructure characterization of nanocrystalline TiC synthesized by mechanical alloying

International Nuclear Information System (INIS)

Ghosh, B.; Pradhan, S.K.

2010-01-01

Nanocrystalline TiC is produced by mechanical milling the stoichiometric mixture of α-Ti and graphite powders at room temperature under argon atmosphere within 35 min of milling through a self-propagating combustion reaction. Microstructure characterization of the unmilled and ball-milled samples was done by both X-ray diffraction and electron microscopy. It reveals the fact that initially graphite layers were oriented along and in the course of milling, thin graphite layers were distributed evenly among the grain boundaries of α-Ti particles. Both α-Ti and TiC lattices contain stacking faults of different kinds. The grain size distribution obtained from the Rietveld's method and electron microscopy studies ensure that nanocrystalline TiC particles with almost uniform size (∼13 nm) can be prepared by mechanical alloying technique. The result obtained from X-ray analysis corroborates well with the microstructure characterization of nanocrystalline TiC by electron microscopy.

Thermal stability of grain boundaries in nanocrystalline Zn studied by positron lifetime spectroscopy

International Nuclear Information System (INIS)

Zhou Kai; Li Hui; Pang Jinbiao; Wang Zhu

2012-01-01

Nanocrystalline Zn prepared by compacting nanoparticles with mean grain size about 55 nm at 15 MPa has been studied by positron lifetime spectroscopy. For the bulk Zn sample, the vacancy defect is annealed out at about 350 °C, but for the nanocrystalline Zn sample, the vacancy cluster in grain boundaries is quite difficult to be annealed out even at very high temperature (410 °C). In the grain boundaries of nanocrystalline Zn, the small free volume defect (not larger than divacancy) is dominant according to the high relative intensity for the short positron lifetime (τ 1 ). The oxide (ZnO) inside the grain boundaries has been found having an effect to hinder the decrease of average positron lifetime (τ av ), which probably indicates that the oxide stabilizes the microstructure of the grain boundaries. This stabilization is very important for the nanocrystalline materials using as radiation resistant materials.

Enhanced photovoltaic performance of dye-sensitized solar cells based on NaYF4:Yb(3+), Er(3+)-incorporated nanocrystalline TiO2 electrodes.

Science.gov (United States)

Zhu, Guang; Wang, Hongyan; Zhang, Quanxin; Zhang, Li

2015-08-01

Near infrared to visible up-conversion of light by rare earth ion-doped phosphors (NaYF4:Yb(3+), Er(3+)) that convert multiple photons of lower energy to higher energy photons offer new possibilities for improved performance of photovoltaic devices. Here, up-conversion phosphor NaYF4:Yb(3+), Er(3+) doped nanocrystalline TiO2 films are designed and used as a electrode for dye-sensitized solar cells, and the photovoltaic performance of DSSCs based on composite electrodes are investigated. The results show the cell with NaYF4:Yb(3+), Er(3+) achieves a power conversion efficiency of 7.65% under one sun illumination (AM 1.5G, 100mWcm(-2)), which is an increase of 14% compared to the cell without NaYF4:Yb(3+), Er(3+) (6.71%). The performance improvement is attributed to the dual effects of enhanced light harvesting from extended light absorption range and increased light scattering, and lower electron transfer resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

Magnetic behavior of nanocrystalline nickel ferrite

International Nuclear Information System (INIS)

Nathani, H.; Gubbala, S.; Misra, R.D.K.

2005-01-01

In the previous papers [R.D.K. Misra, A. Kale, R.S. Srivatsava, O. Senkov, Mater. Sci. Technol. 19 (2003) 826; R.D.K. Misra, A. Kale, B. Hooi, J.Th. DeHosson, Mater. Sci. Technol. 19 (2003) 1617; A. Kale, S. Gubbala, R.D.K. Misra, J. Magn. Magn. Mater. 277 (2004) 350; S. Gubbala, H. Nathani, K. Koizol, R.D.K. Misra, Phys. B 348 (2004) 317; R.D.K. Misra, S. Gubbala, A. Kale, W.F. Egelhoff, Mater. Sci. Eng. B. 111 (2004) 164], we reported the synthesis, structural characterization and magnetic behavior of nanocrystalline ferrites of inverse and mixed spinel structure made by reverse micelle technique that enabled a narrow particle size distribution to be obtained. In the present paper, the reverse micelle approach has been extended to synthesize nanocrystalline ferrites with varying surface roughness of 8-18 A (the surface roughness was measured by atomic force microscopy) and the magnetic behavior studied by SQUID magnetometer. Two different kinds of measurement were performed: (a) zero-field cooling (ZFC) and field cooling (FC) magnetization versus temperature measurements and (b) magnetization as a function of applied field. The analysis of magnetic measurement suggests significant influence of surface roughness of particles on the magnetic behavior. While the superparamagnetic behavior is retained by the nanocrystalline ferrites of different surface roughness at 300 K, the hysteresis loop at 2 K becomes non-squared and the coercivity increases with increase in surface roughness. This behavior is discussed in terms of broken bonds and degree of surface spin disorder

Direct examination of cadmium bonding in rat tissues dosed with mine wastes and cadmium-containing solutions

International Nuclear Information System (INIS)

Diacomanolis, V.; Ng, J. C.; Sadler, R.; Harris, H. H.; Nomura, M.; Noller, B. N.

2010-01-01

Direct examination by XANES and EXAFS of metal bonding in tissue can be demonstrated by examining cadmium uptake and bonding in animal tissue maintained at cryogenic temperatures. XANES at the K-edge of cadmium were collected at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Rats fed with 1g mine waste containing 8-400 mg/kg cadmium per 200g body weight (b.w.) or dosed by oral gavage with either cadmium chloride solution alone (at 6 mg/kg b.w.) or in combination with other salts (As, Cu or Zn), 5 days/week for 6 weeks, had 0.1-7.5 and 8-86 mg/kg cadmium in the liver or kidney, respectively. Rats given intraperitoneally (ip) or intravenously (iv) 1-4 times with 1 mg/kg b.w. cadmium solution had 30-120 mg/kg cadmium in the liver or kidney. Tissues from rats were kept and transferred at cryogenic temperature and XANES were recorded at 20 K. The spectra for rat liver samples suggested conjugation of cadmium with glutathione or association with the sulfide bond (Cd-S) of proteins and peptides. EXAFS of rat liver fed by Cd and Zn solutions showed that Cd was clearly bound to S ligands with an inter-atomic distance of 2.54 A ring for Cd-S that was similar to cadmium sulfide with an inter-atomic distance of 2.52 A ring for Cd-S. Liver or kidney of rats fed with mine wastes did not give an edge in the XANES spectra indicating little uptake of cadmium by the animals. Longer and higher dosing regimen may be required in order to observe the same Cd-S bond in the rat tissue from mine wastes, including confirmation by EXAFS.

XRD and HREM studies of nanocrystalline Cu and Pd

International Nuclear Information System (INIS)

Nieman, G.W.; Weertmen, J.R.; Siegel, R.W.

1991-01-01

Consolidated powders of nanocrystalline Cu and Pd have been studied by x-ray diffraction (XRD) and high resolution electron microscopy (HREM) as part of an investigation of the mechanical behavior of nanocrystalline pure metals. XRD line broadening measurements were made to estimate rain size, qualitative grain size distribution and average long range strains in a number of samples. Mean grain sized range from 4-60 nm and have qualitatively narrow grain size distributions. Long range lattice strains are of the order of 0.2-3% in consolidated samples. These strains apparently persist and even increase in Cu samples after annealing at 0.35 Tm (498K) for 2h, accompanied by an apparent increase in grain size of ≥2x. Grain size, grain size distribution width and internal strains vary somewhat among samples produced under apparently identical processing conditions. HREM studies show that twins, stacking faults and low-index facets are abundant in as-consolidated nanocrystalline Cu samples. In this paper methodology, results and analysis of XRD and HREM experiments are presented

Formation of local nanocrystalline structure in a boron steel induced by electropulsing

International Nuclear Information System (INIS)

Ma, Bingdong; Zhao, Yuguang; Ma, Jun; Guo, Haichao; Yang, Qing

2013-01-01

Highlights: ► The local NC structures in the uniform size of ∼15 nm were obtained by electropulsing. ► The NC structures were made up of γ-Fe without any other phases coexisting. ► The reduction in nucleation barrier of the γ-Fe helped form the local γ-Fe NC structure. ► The steel consisting of the lath martensitic and the γ-Fe nanocrystalline structure exhibits high mechanical properties. - Abstract: Nanocrystalline γ-Fe was obtained locally in a cold-rolled boron steel as a result of transient high-energy electropulsing. The nano-grains of γ-Fe were uniformly about 15 nm in size. No phases other than γ-Fe have been found in the nanocrystalline structure. It is believed that the pulse current enhances the nucleation rate of γ-Fe phase during the phase transformation from α-Fe to γ-Fe, resulting in the formation of local nanostructure. Moreover, in this study the steel consisting of the lath martensitic and the γ-Fe nanocrystalline structure exhibits high mechanical properties.

Cadmium colours: composition and properties

International Nuclear Information System (INIS)

Paulus, J.; Knuutinen, U.

2004-01-01

The composition and the properties of cadmium aquarelle colours are discussed. The examined colours were 24 different aquarelle cadmium colours from six different manufacturers. The colours ranged from light, bright yellows to dark, deep-red tones. The aim of this research was to find out if the pigments contain cadmium salts: sulphides and/or selenides. This information will help in choosing watercolours in conservation processes. Today, aquarelle colours not containing cadmium pigments are being sold as cadmium colours; thus their properties might be different from actual cadmium colours. The aim of the research was to verify that the colour samples contained cadmium pigments and to estimate their compositions and ageing properties. Element analyses were performed from colour samples using micro-chemical tests and X-ray fluorescence measurements. Thin-layer chromatography was used for analysing gum Arabic as a possible binding medium in the chosen colour samples. Through ageing tests, the resistance of the colour samples to the exposure to light, heat and humidity was studied. Visible-light spectroscopy was used in determining the hues and hue changes of the aquarelle colour samples. The spectrophotometer used the CIE L * a * b * tone colour measuring system. From the colour measurements the changes in the lightness/darkness, the redness, the yellowness and the saturation of the samples were examined. (orig.)

Direct separation of short range order in intermixed nanocrystalline and amorphous phases

International Nuclear Information System (INIS)

Frenkel, Anatoly I.; Kolobov, Alexander V.; Robinson, Ian K.; Cross, Julie O.; Maeda, Yoshihito; Bouldin, Charles E.

2002-01-01

Diffraction anomalous fine-structure (DAFS) and extended x-ray absorption fine-structure (EXAFS) measurements were combined to determine short range order (SRO) about a single atomic type in a sample of mixed amorphous and nanocrystalline phases of germanium. EXAFS yields information about the SRO of all Ge atoms in the sample, while DAFS determines the SRO of only the ordered fraction. We determine that the first-shell distance distribution is bimodal; the nanocrystalline distance is the same as the bulk crystal, to within 0.01(2) A ring , but the mean amorphous Ge-Ge bond length is expanded by 0.076(19) Angstrom. This approach can be applied to many systems of mixed amorphous and nanocrystalline phases

Cadmium toxcity in the pregnant rat

International Nuclear Information System (INIS)

Martin, P.G.; Hitchcock, B.B.; King, J.F.

1978-01-01

Iron-deficient and normal pregnant rats were assigned to groups that either received a dose of cadmium (0.025, 0.050, or 0.100 mmole) plus 8 μCi of /sup 115m/Cd on day 18 of gestation or served as a nondosed group. Animals were either sacrificed 3 days after the dosing or allowed to litter (nondosed and 0.100 mmole cadmium groups only); pups and dams were sacrificed at 14 days of age. Viability of iron-deficient dams and fetuses and pups from iron-deficient dams was affected by the 0.100 mmole cadmium dose to a greater degree than was that in comparable normal animals. Although calculated amounts of cadmium deposited in the dam's liver, kidney, blood, tibia, and fetuses were greater in iron-deficient than in normal animals at all doses, differences were not significant except in the amount of cadmium accumulated in the placenta at the highest cadmium doses. Total deposition in the placentas/litter was similar for normal and iron-deficient groups at each dose level. The decreased viability may have been due to the dam's decreased food intake; blockage of nutrients, especially minerals, by cadmium--protein complexes in the placenta; or hormonal interruptions of pregnancy by steroid--cadmium complexes

Cadmium - a case of mistaken identity

Energy Technology Data Exchange (ETDEWEB)

Taylor, D

1984-05-01

New evidence is presented which describes the impact of cadmium in the environment. Cadmium is a persistent material, although its compounds may undergo a range of chemical changes in the environment. In soluble form cadmium and its compounds are toxic at relatively low concentrations to aquatic animals although their bioconcentrations in such animals is in general low, and there is no evidence of biomagnification. In insoluble form cadmium and its compounds are relatively non-toxic to aquatic animals and are unlikely to be bioconcentrated. As such, cadmium is similar to most other heavy metals. Recent studies indicate that cadmium is not implicated in Itai-Itai disease and does not appear to cause hypertension or cancer. In addition, the accepted critical level in the kidney may have been underestimated. Thus, the hazard to man appears to be considerably less than the original estimates. In view of these data, there seems little justification in treating cadmium in any way differently from the other metals and hence no reason for retaining it on the Black List of the international conventions. 19 references.

The Graphene/l-Cysteine/Gold-Modified Electrode for the Differential Pulse Stripping Voltammetry Detection of Trace Levels of Cadmium

Directory of Open Access Journals (Sweden)

Yu Song

2016-06-01

Full Text Available Cadmium(II is a common water pollutant with high toxicity. It is of significant importance for detecting aqueous contaminants accurately, as these contaminants are harmful to human health and environment. This paper describes the fabrication, characterization, and application of an environment-friendly graphene (Gr/l-cysteine/gold electrode to detect trace levels of cadmium (Cd by differential pulse stripping voltammetry (DPSV. The influence of hydrogen overflow was decreased and the current response was enhanced because the modified graphene extended the potential range of the electrode. The Gr/l-cysteine/gold electrode showed high electrochemical conductivity, producing a marked increase in anodic peak currents (vs. the glass carbon electrode (GCE and boron-doped diamond (BDD electrode. The calculated detection limits are 1.15, 0.30, and 1.42 µg/L, and the sensitivities go up to 0.18, 21.69, and 152.0 nA·mm−2·µg−1·L for, respectively, the BDD electrode, the GCE, and the Gr/l-cysteine/gold electrode. It was shown that the Gr/l-cysteine/gold-modified electrode is an effective means for obtaining highly selective and sensitive electrodes to detect trace levels of cadmium.

Health hazards of environmental cadmium pollution

Energy Technology Data Exchange (ETDEWEB)

Nordberg, G F

1974-01-01

Cadmium, a metal widely used in industrial processes, has been recognized to be a highly toxic and dangerous environmental pollutant. In this study the author describes the sources and occurrence of cadmium, and the intake by human beings. He states that present standards for daily intake do not allow sufficient safety margins. The fate and known effects of cadmium in human beings are summarized; some effects associated with cadmium are renal (kidney) damage, anemia, hypertension, and liver damage. Cadmium was identified as the main cause of the Itai-Itai disease in Japan, and epidemiological studies from various areas of Japan are presented. 64 references, 9 figures, 5 tables.

Surface Properties of a Nanocrystalline Fe-Ni-Nb-B Alloy After Neutron Irradiation

Science.gov (United States)

Pavùk, Milan; Sitek, Jozef; Sedlačková, Katarína

2014-09-01

The effect of neutron radiation on the surface properties of the nanocrystalline (Fe0.25Ni0.75)81Nb7B12 alloy was studied. Firstly, amorphous (Fe0.25Ni0.75)81Nb7B12 ribbon was brought by controlled annealing to the nanocrystalline state. After annealing, the samples of the nanocrystalline ribbon were irradiated in a nuclear reactor with neutron fluences of 1×1016cm-2 and 1 × 1017cm-2 . By utilizing the magnetic force microscopy (MFM), topography and a magnetic domain structure were recorded at the surface of the ribbon-shaped samples before and after irradiation with neutrons. The results indicate that in terms of surface the nanocrystalline (Fe0.25Ni0.75)81Nb7B12 alloy is radiation-resistant up to a neutron fluence of 1 × 1017cm-2 . The changes in topography observed for both irradiated samples are discussed

Cadmium removal by Lemna minor and Spirodela polyrhiza.

Science.gov (United States)

Chaudhuri, Devaleena; Majumder, Arunabha; Misra, Amal K; Bandyopadhyay, Kaushik

2014-01-01

The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5,1.0,1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42-78% and 52-75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bioconcentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator.

Influence of cobalt doping on structural and magnetic properties of BiFeO3 nanoparticles

Science.gov (United States)

Khan, U.; Adeela, N.; Javed, K.; Riaz, S.; Ali, H.; Iqbal, M.; Han, X. F.; Naseem, S.

2015-11-01

Nanocrystalline cobalt-doped bismuth ferrites with general formula of BiFe1- δ Co δ O3 (0 ≤ δ ≤ 0.1) have been synthesized using solution evaporation method. Structure and phase identification was performed with X-ray diffraction (XRD) technique. The results confirm the formation of rhombohedral-distorted Perovskite structure with R3c symmetry. A decrease in lattice parameters and an increase in X-ray density have been observed with increasing cobalt concentration in BiFeO3. Particle size determined by transmission electron microscope was in good agreement with XRD, i.e., 39 nm. Room-temperature coercivity and saturation magnetization of nanoparticles were increased up to 7.5 % of cobalt doping. Low-temperature magnetic measurements of selected sample showed increasing behavior in saturation magnetization, coercivity, effective magnetic moments, and anisotropy constant. An increase in coercivity with decrease in temperature followed theoretical model of Kneller's law, while modified Bloch's model was employed for saturation magnetization in temperature range of 5-300 K.

Cadmium Exposure is Associated with the Prevalence of Dyslipidemia

Directory of Open Access Journals (Sweden)

Zhou Zhou

2016-11-01

Full Text Available Background: Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the prevalence of dyslipidemia, we examined the associations between blood cadmium concentration and the prevalence of dyslipidemia in workers occupationally exposed to cadmium in China. Methods: A cross-sectional survey on demographic data, blood cadmium level and lipid profile in cadmium exposed workers from seven cadmium smelting factories in central and southwestern China was conducted. We measured blood cadmium concentration and lipid components of 1489 cadmium exposed workers. The prevalence of dyslipidemia was compared across blood cadmium quartiles. Associations between the blood cadmium concentrations and the prevalence of dyslipidemia were assessed using confounder adjusted linear and logistic regressions. Results: The blood cadmium concentration was 3.61±0.84µg/L ( mean ±SD. The prevalence of dyslipidemia in this occupational population was 66.3%. Mean blood cadmium concentration of workers with dyslipedemia was significantly higher than that of workers without dyslipidemia (p Conclusion: Elevated blood cadmium concentration is associated with prevalence of dyslipidemia. Cadmium exposure could alter lipid metabolism in humans. It is imperative to control cadmium exposure of occupational population in cadmium related industries and reduce adverse health effects.

Paramagnetic centers in nanocrystalline TiC/C system

International Nuclear Information System (INIS)

Guskos, N.; Bodziony, T.; Maryniak, M.; Typek, J.; Biedunkiewicz, A.

2008-01-01

Electron paramagnetic resonance is applied to study the defect centers in nanocrystalline titanium carbide dispersed in carbon matrix (TiC x /C) synthesized by the non-hydrolytic sol-gel process. The presence of Ti 3+ paramagnetic centers is identified below 120 K along with a minor contribution from localized defect spins coupled with the conduction electron system in the carbon matrix. The temperature dependence of the resonance intensity of the latter signal indicates weak antiferromagnetic interactions. The presence of paramagnetic centers connected with trivalent titanium is suggested to be the result of chemical disorder, which can be further related to the observed anomalous behavior of conductivity, hardness, and corrosion resistance of nanocrystalline TiC x /C

Production of nanocrystalline metal powders via combustion reaction synthesis

Science.gov (United States)

Frye, John G.; Weil, Kenneth Scott; Lavender, Curt A.; Kim, Jin Yong

2017-10-31

Nanocrystalline metal powders comprising tungsten, molybdenum, rhenium and/or niobium can be synthesized using a combustion reaction. Methods for synthesizing the nanocrystalline metal powders are characterized by forming a combustion synthesis solution by dissolving in water an oxidizer, a fuel, and a base-soluble, ammonium precursor of tungsten, molybdenum, rhenium, or niobium in amounts that yield a stoichiometric burn when combusted. The combustion synthesis solution is then heated to a temperature sufficient to substantially remove water and to initiate a self-sustaining combustion reaction. The resulting powder can be subsequently reduced to metal form by heating in a reducing gas environment.

Cadmium Exposure is Associated with the Prevalence of Dyslipidemia.

Science.gov (United States)

Zhou, Zhou; Lu, Yong-Hui; Pi, Hui-Feng; Gao, Peng; Li, Min; Zhang, Lei; Pei, Li-Ping; Mei, Xiang; Liu, Lin; Zhao, Qi; Qin, Qi-Zhong; Chen, Yu; Jiang, Yue-Ming; Zhang, Zhao-Hui; Yu, Zheng-Ping

2016-01-01

Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the prevalence of dyslipidemia, we examined the associations between blood cadmium concentration and the prevalence of dyslipidemia in workers occupationally exposed to cadmium in China. A cross-sectional survey on demographic data, blood cadmium level and lipid profile in cadmium exposed workers from seven cadmium smelting factories in central and southwestern China was conducted. We measured blood cadmium concentration and lipid components of 1489 cadmium exposed workers. The prevalence of dyslipidemia was compared across blood cadmium quartiles. Associations between the blood cadmium concentrations and the prevalence of dyslipidemia were assessed using confounder adjusted linear and logistic regressions. The blood cadmium concentration was 3.61±0.84µg/L ( mean ±SD). The prevalence of dyslipidemia in this occupational population was 66.3%. Mean blood cadmium concentration of workers with dyslipedemia was significantly higher than that of workers without dyslipidemia (p dyslipidemia increased dose-dependently with elevations in blood cadmium concentrations (p for trend dyslipidemia across the increasing blood cadmium quartiles were 1.21(1.16-1.55), 1.56(1.11-1.87), 1.79(1.26-2.25) respectively (referencing to 1.00; p for trend dyslipidemia remained unchanged (all p for trend dyslipidemia. Cadmium exposure could alter lipid metabolism in humans. It is imperative to control cadmium exposure of occupational population in cadmium related industries and reduce adverse health effects. © 2016 The

Preparation of manganese doped cadmium sulfide nanoparticles in zincblende phase and their magnetic properties.

Science.gov (United States)

Nakaya, Masafumi; Tanaka, Itaru; Muramatsu, Atsushi

2012-12-01

In this study, the random dope of Mn into CdS nanoparticles in zincblende phase has been carried out under the mild reaction condition. The resulting nanoparticles were characterized by energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffractometer (XRD), UV-Vis spectrometer, PL spectrometer, and SQUID. EDX showed that the compositions of Mn doped CdS nanoparticles were readily controlled. TEM showed the particle sizes were not significantly affected by the compositions, retaining to be ca. 3 nm with a narrow size distribution. UV-Vis and PL spectra of the resulting nanoparticles showed the intra-Mn level may be affected by the quantum size effect. SQUID measurement showed that the resulting nanoparticles showed diamagnetism, paramagnetism and superparamagnetism dependent on Mn content.

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

Science.gov (United States)

Neogi, S. K.; Karmakar, R.; Misra, A. K.; Banerjee, A.; Das, D.; Bandyopadhyay, S.

2013-11-01

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn1-xMnxO samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol-gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO3) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ1 and τ2 are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. Single phase structure has been observed up to 6 at% of Mn doping. Impurity phase has been developed above 6 at% of Mn doping. Antiferromagnetic and paramagnetic interactions are present in the samples. Defect parameters show sharp fall as Mn concentration above 6 at%. The magnetic and defect properties are modified by the formation of impurity phase.

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

International Nuclear Information System (INIS)

Neogi, S.K.; Karmakar, R.; Misra, A.K.; Banerjee, A.; Das, D.; Bandyopadhyay, S.

2013-01-01

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn 1−x Mn x O samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol–gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO 3 ) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ 1 and τ 2 are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. - highlights: • Single phase structure has been observed up to 6 at% of Mn doping. • Impurity phase has been developed above 6 at% of Mn doping. • Antiferromagnetic and paramagnetic interactions are present in the samples. • Defect parameters show sharp fall as Mn concentration above 6 at%. • The magnetic and defect properties are modified by the formation of impurity phase

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

Energy Technology Data Exchange (ETDEWEB)

Neogi, S.K.; Karmakar, R. [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); Misra, A.K. [UGC DAE Consortium for Scientific Research, Salt Lake, Kolkata 700064 (India); Banerjee, A. [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); CRNN, University of Calcutta, JD 2, Sector III, Salt Lake, Kolkata 700098 (India); Das, D. [UGC DAE Consortium for Scientific Research, Salt Lake, Kolkata 700064 (India); Bandyopadhyay, S., E-mail: sbaphy@caluniv.ac.in [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); CRNN, University of Calcutta, JD 2, Sector III, Salt Lake, Kolkata 700098 (India)

2013-11-15

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn{sub 1−x}Mn{sub x}O samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol–gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO{sub 3}) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ{sub 1} and τ{sub 2} are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. - highlights: • Single phase structure has been observed up to 6 at% of Mn doping. • Impurity phase has been developed above 6 at% of Mn doping. • Antiferromagnetic and paramagnetic interactions are present in the samples. • Defect parameters show sharp fall as Mn concentration above 6 at%. • The magnetic and defect properties are modified by the formation of impurity phase.

Effects of oxide distributed in grain boundaries on microstructure stability of nanocrystalline metals

Science.gov (United States)

Zhou, Kai; Li, Hui; Biao Pang, Jin; Wang, Zhu

2013-06-01

Nanocrystalline copper and zinc prepared by high-pressure compaction method have been studied by positron lifetime spectroscopy associated with X-ray diffraction. For nanocrystalline Cu, mean grain sizes of the samples decrease after being annealed at 900 °C and increase during aging at 180 °C, revealing that the atoms exchange between the two regions. The positron lifetime results indicate that the vacancy clusters formed in the annealing process are unstable and decomposed at the aging time below 6 hours. In addition, the partially oxidized surfaces of the nanoparticles hinder the grain growth during the ageing at 180 °C, and the vacancy clusters inside the disorder regions which are related to Cu2O need longer aging time to decompose. In the case of nanocrystalline Zn, the open volume defect (not larger than divacancy) is dominant according to the high relative intensity for the short positron lifetime (τ1). The oxide (ZnO) inside the grain boundaries has been found having an effect to hinder the decrease of average positron lifetime (τav) during the annealing, which probably indicates that the oxide stabilizes the microstructure of the grain boundaries. For both nanocrystalline copper and zinc, the oxides in grain boundaries enhance the thermal stability of the microstucture, in spite of their different crystal structures. This effect is very important for the nanocrystalline materials using as radiation resistant materials.

Effects of oxide distributed in grain boundaries on microstructure stability of nanocrystalline metals

International Nuclear Information System (INIS)

Zhou Kai; Li Hui; Pang Jinbiao; Wang Zhu

2013-01-01

Nanocrystalline copper and zinc prepared by high-pressure compaction method have been studied by positron lifetime spectroscopy associated with X-ray diffraction. For nanocrystalline Cu, mean grain sizes of the samples decrease after being annealed at 900 °C and increase during aging at 180 °C, revealing that the atoms exchange between the two regions. The positron lifetime results indicate that the vacancy clusters formed in the annealing process are unstable and decomposed at the aging time below 6 hours. In addition, the partially oxidized surfaces of the nanoparticles hinder the grain growth during the ageing at 180 °C, and the vacancy clusters inside the disorder regions which are related to Cu 2 O need longer aging time to decompose. In the case of nanocrystalline Zn, the open volume defect (not larger than divacancy) is dominant according to the high relative intensity for the short positron lifetime (τ 1 ). The oxide (ZnO) inside the grain boundaries has been found having an effect to hinder the decrease of average positron lifetime (τ av ) during the annealing, which probably indicates that the oxide stabilizes the microstructure of the grain boundaries. For both nanocrystalline copper and zinc, the oxides in grain boundaries enhance the thermal stability of the microstucture, in spite of their different crystal structures. This effect is very important for the nanocrystalline materials using as radiation resistant materials.

Reviews of the environmental effects of pollutants: IV. Cadmium

International Nuclear Information System (INIS)

Hammons, A.S.; Huff, J.E.; Braunstein, H.M.; Drury, J.S.; Shriner, C.R.; Lewis, E.B.; Whitfield, B.L.; Towill, L.E.

1978-06-01

This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 μg per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels

Reviews of the environmental effects of pollutants: IV. Cadmium

Energy Technology Data Exchange (ETDEWEB)

Hammons, A.S.; Huff, J.E.; Braunstein, H.M.; Drury, J.S.; Shriner, C.R.; Lewis, E.B.; Whitfield, B.L.; Towill, L.E.

1978-06-01

This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 ..mu..g per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels.

Nanocrystalline magnetite thin films grown by dual ion-beam sputtering

International Nuclear Information System (INIS)

Prieto, Pilar; Ruiz, Patricia; Ferrer, Isabel J.; Figuera, Juan de la; Marco, José F.

2015-01-01

Highlights: • We have grown tensile and compressive strained nanocrystalline magnetite thin films by dual ion beam sputtering. • The magnetic and thermoelectric properties can be controlled by the deposition conditions. • The magnetic anisotropy depends on the crystalline grain size. • The thermoelectric properties depend on the type of strain induced in the films. • In plane uniaxial magnetic anisotropy develops in magnetite thin films with grain sizes ⩽20 nm. - Abstract: We have explored the influence of an ion-assisted beam in the thermoelectric and magnetic properties of nanocrystalline magnetite thin films grown by ion-beam sputtering. The microstructure has been investigated by XRD. Tensile and compressive strained thin films have been obtained as a function of the parameters of the ion-assisted beam. The evolution of the in-plane magnetic anisotropy was attributed to crystalline grain size. In some films, magneto-optical Kerr effect measurements reveal the existence of uniaxial magnetic anisotropy induced by the deposition process related with a small grain size (⩽20 nm). Isotropic magnetic properties have observed in nanocrystalline magnetite thin film having larger grain sizes. The largest power factor of all the films prepared (0.47 μW/K 2 cm), obtained from a Seebeck coefficient of −80 μV/K and an electrical resistivity of 13 mΩ cm, is obtained in a nanocrystalline magnetite thin film with an expanded out-of-plane lattice and with a grain size ≈30 nm

Cadmium-induced fetal toxicity in the rat

International Nuclear Information System (INIS)

Levin, A.A.

1980-01-01

Cadmium, a heavy metal environment contaminant, induces fetal death and placental necrosis in the Wistar rat. This study investigated fetal, maternal, and placental responses to cadmium intoxication. Subcutaneous injection of CdCl 2 to dams on day 18 of pregnancy produced a high incidence of fetal death (75%) and placental necrosis. Death in the fetus was produced despite limited fetal accumulations of cadmium. Distribution studies using 109 Cd-labeled CdCl 2 demonstrated that less than 0.1% of the injected dose was associated with the fetus. To determine if fetuses were sensitive to these low levels of cadmium, direct injections of CdCl 2 into fetuses were performed in utero. Direct injections produced fetal accumulations 8-fold greater than those following maternal injections. The 8-fold greater fetal accumulations following direct injection were associated with only a 12% fetal mortality compared to the 75% mortality following maternal injections. The data indicated that the fetal toxicity of cadmium following maternal injections was not the result of direct effects of cadmium on the fetus. In conclusion, cadmium-induced fetal death was not the result of direct effects of cadmium on the fetus but may have been induced by placental cellular injury resulting from high accumulations of cadmium in the placenta. A vascular response to placental injury, leading to decreased utero-placental bood flow and cadmium-induced alterations in trophoblastic function, resulted in fetal death

Cadmium in Salix. A study to show the capacity of Salix to remove cadmium from farmland

International Nuclear Information System (INIS)

Oestman, G.

1994-01-01

The aim of this report has been to show the ability of Salix to take up cadmium and how the uptake varies between different types of soil. The information that the results are based on has been obtained from analyses of soil and Salix. The samples were taken at five sites in the district around Lake Maelaren. Two or three stands were taken at each place. The factors studied were the pH, the organic matter content, and the concentration of cadmium in the soil. Salix has a good ability, relative to other crops, to remove cadmium from arable land. The cadmium uptake is 35 times higher with Salix than with straw or energy grass. Salix uptake of cadmium varies between 3 and 14% of the cadmium content in the soil that is accessible to plants. The present annual increase of cadmium in arable land is 1 g/ha, whereas the removal in a Salix plantation is 21 g Cd/ha, yr at an annual growth of 10 tonnes DM. If the Cd uptake is the same each year, then a total of 420 g Cd/ha is removed when Salix is grown over a 20-year period. This is a very large part of the topsoil's total cadmium content, which is 550 g/ha on average in Sweden. The investigation reveals no clear relationship between the Cd concentration in Salix and the concentration of Cd in the soil, the organic matter content or the pH. 22 refs, 4 figs, 2 tabs

Use of cadmium in solution in the EL 4 reactor moderator irreversible fixing of cadmium on the metallic surfaces; Utilisation du cadmium en solution dans le moderateur du reacteur EL 4 - fixation irreversible du cadmium sur les surfaces metalliques

Energy Technology Data Exchange (ETDEWEB)

Croix, O; Paoli, O; Lecomte, J; Dolle, L; Gallic, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

In the framework of research into the poisoning of the EL-4 reactor by cadmium sulphate, measurements have been made by two different methods of the residual amounts of cadmium liable to be fixed irreversibly on the surfaces in contact with the heavy water. A marked influence of the pH has been noticed. The mechanism of the irreversible fixing is compatible with the hypothesis of an ion-exchange in the surface oxide layer. In a sufficiently wide range of pH the cadmium thus fixed causes very little residual poisoning. The stability of the cadmium sulphate solutions is however rather low in the conditions of poisoning. (authors) [French] Dans le cadre des etudes sur l'empoisonnement du reacteur EL-4 par le sulfate de cadmium, les quantites residuelles de cadmium susceptibles de se fixer irreversiblement sur les parois que mouillerait l'eau lourde, ont ete mesurees experimentalement par deux methodes differentes. On observe une influence nette du pH. Le mecanisme de la fixation irreversible est compatible avec l'hypothese d'un echange d'ions dans la pellicule d'oxyde superficielle. Dans des limites suffisamment larges de pH, la cadmium ainsi fixe n'occasionne pas d'empoisonnement residuel important. La stabilite des solutions de sulfate de cadmium dans les conditions de l'empoisonnement est cependant mediocre. (auteurs)

Cadmium incorporation by the marine copepod Pseudodiaptomus coronatus

International Nuclear Information System (INIS)

Sick, L.V.; Baptist, G.J.

1979-01-01

Pseudodiaptomus coronatus, after exposure to phytoplankton and cadmium in concentrations like those in temperate, coastal environments, incorporated 109 Cd at higher rates from ambient water than from phytoplankton food. When ambient stable cadmium concentrations were increased from 0.03 to 1.00 μg.liter -1 , cadmium concentration by phytoplankton cells increased and the rate of cell ingestion by P. coronatus decreased. This inverse relation between the accumulation of cadmium in phytoplankton cells and the animal's ingestion rate resulted in relatively small net increases in the cadmium accumulated from phytoplankton by copepods. Rates of stable cadmium ingestion for P. coronatus ranged from 0.18 to 0.38 ng.mg animal dry wt -1 .h -1 , depending on the initial algal cell density and the ambient cadmium concentration. For cadmium concentrations of 0.03 to 1.00 μg.liter -1 , percentage assimilation efficiencies ranged from 13.20 to 68.40. Both rates of cadmium ingestion and assimilation efficiencies were higher than published values for carnivorous zooplankton

Vibrational thermodynamics of Fe90Zr7B3 nanocrystalline alloy from nuclear inelastic scattering

DEFF Research Database (Denmark)

Stankov, S.; Miglierini, M.; Chumakov, A. I.

2010-01-01

Recently we determined the iron-partial density of vibrational states (DOS) of nanocrystalline Fe(90)Zr(7)B(3) (Nanoperm), synthesized by crystallization of an amorphous precursor, for various stages of nanocrystallization separating the DOS of the nanograins from that of the interfaces [S. Stank......, vibrational entropy, and lattice specific heat as the material transforms from amorphous, through nanocrystalline, to fully crystallized state. The reported results shed new light on the previously observed anomalies in the vibrational thermodynamics of nanocrystalline materials....

Growth of doped Pb S:Co{sup 2+} nano crystals by chemical bath

Energy Technology Data Exchange (ETDEWEB)

Portillo M, O.; Gutierrez P, R.; Chavez P, M.; Marquez S, M. N.; Hernandez T, G.; Lazcano H, M.; Moreno R, A. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Laboratorio de Ciencia de Materiales, Apdo. Postal 1067, 72001 Puebla, Pue. (Mexico); Palomino M, R. [Universidad Autonoma de Puebla, Facultad de Ciencias Fisico-Matematicas, Posgrado en Fisica Aplicada, 72001 Puebla, Pue. (Mexico); Rubio R, E., E-mail: osporti@yahoo.com.mx [Universidad Autonoma de Puebla, Centro Universitario de Vinculacion y Transferencia de Tecnologia, 72001 Puebla, Pue. (Mexico)

2016-11-01

Nanocrystalline Pb S films grown by chemical bath at T = 40 ± 2 degrees Celsius onto glass slides were modified by in situ Co{sup 2+} -doping and their structural and optical properties were examined. By Ft-IR spectra, a sharp stretching mode can be seen at ∼1384 cm{sup -1} due to the vibration mode of CO{sup 2/3} ions. X-ray diffraction patterns shown the growth on the zinc blende crystalline face. The grain size was determined by using X-rays diffractograms and was found at ∼28 nm and ∼13 - 25 nm for undoped and doped samples, respectively. Optical absorption spectra was used for calculating the energy band gap, and displayed a shift in the ∼1.21 - 2.21 eV range, associated with quantum confinement effect. Raman peaks at ∼210, 271 and 451 cm{sup -1}, corresponding to a 1LO phonon mode, a two-phonon process, and a 2LO phonon mode respectively were also recorded. The surface and grain size of the films were measured by atomic force microscopy studies. (Author)

Synthesis, characterization, and analysis of enhanced photocatalytic activity of Zr-doped TiO2 nanostructured powders under UV light

Science.gov (United States)

Sekhar, M. Chandra; Purusottam Reddy, B.; Mallikarjuna, K.; Shanmugam, Gnanendra; Ahn, Chang-Hoi; Park, Si-Hyun

2018-01-01

Zr-doped and pure TiO2 nanoparticles (NPs) were synthesized using a simple inexpensive sol-gel method. X-ray powder diffractometry and Fourier transform infrared spectrometry revealed the presence of anatase-phase TiO2 NPs. Scanning electron microscopy and transmission electron microscopy revealed that the average nanocrystalline size of approximately 15 nm. The photocatalytic activities of these materials were evaluated using Rhodamine B (Rh B) as an organic contaminant. The photocatalytic activity of pure and Zr-doped TiO2 NPs (with at% 4, 8, 12 and 16) was measured in terms of the degradation of Rh B under UV light. The antibacterial activities of pure and Zr-doped (with 8 at%) TiO2 NPs were evaluated against Bacillus subtillis, Escherichia coli, and Pseudomonas aeruginosa. A maximum inhibition zone (19 mm) was observed for pure TiO2 NPs, against Bacillus subtillis and Pseudomonas aeruginosa, while Zr-doped TiO2 (8 at%) exhibited a lesser inhibition zone (18 mm) against the same Bacillus subtillis and Pseudomonas aeruginosa (18 mm). However, Zr-doped TiO2 (8 at%) NPs exhibited a greater inhibition zone against Escherichia coli (17 mm), while the activity of pure TiO2 NPs against Escherichia coli (15 mm) was retarded. Thus, pure TiO2 NPs and Zr-doped TiO2 (8 at%) NPs have competent activities and can be used as antibacterial agents against different bacteria.

Engineering of giant magnetoimpedance effect of amorphous and nanocrystalline microwires

Directory of Open Access Journals (Sweden)

V. Zhukova

2016-12-01

Full Text Available We present our studies of the factors affecting soft magnetic properties and giant magnetoimpedance effect in thin amorphous and nanocrystalline microwires. We showed that the magnetoelastic anisotropy is one of the most important parameters that determine magnetic softness and GMI effect of glass-coated microwires  and annealing can be very effective for manipulation the magnetic properties of amorphous ferromagnetic glass-coated microwires. Considerable magnetic softening and increasing of the GMI effect is observed in Fe-rich nanocrystalline FINEMET-type glass-coated microwires after the nanocrystallization.

Atomic-scale simulations of the mechanical deformation of nanocrystalline metals

DEFF Research Database (Denmark)

Schiøtz, Jakob; Vegge, Tejs; Di Tolla, Francesco

1999-01-01

that the main deformation mode is sliding in the grain boundaries through a large number of uncorrelated events, where a few atoms (or a few tens of atoms) slide with respect to each other. Little dislocation activity is seen in the grain interiors. The localization of the deformation to the grain boundaries......Nanocrystalline metals, i.e., metals in which the grain size is in the nanometer range, have a range of technologically interesting properties including increased hardness and yield strength. We present atomic-scale simulations of the plastic behavior of nanocrystalline copper. The simulations show...

Formation of nanocrystalline MgB sub 2 under high pressure

CERN Document Server

Sun, L; Kikegawa, T; Cao, L; Zhan, Z; Wu, Q; Wu, X; Wang, W

2002-01-01

The microstructural features of MgB sub 2 at ambient pressure and high pressure have been investigated by means of in situ synchrotron radiation x-ray diffraction and transmission electron microscopy (TEM). The x-ray diffraction measurements indicated that nanocrystalline MgB sub 2 formed in the pressure range of 26.3-30.2 GPa. TEM investigations reveal complex structure domains with evident lattice distortion in the relevant samples. The superconductivity of nanocrystalline MgB sub 2 was measured and compared with that of the starting sample of MgB sub 2.

Study on Europium-Doped Hydroxyapatite Nanoparticles by Fourier Transform Infrared Spectroscopy and Their Antimicrobial Properties

Directory of Open Access Journals (Sweden)

Simona-Liliana Iconaru

2013-01-01

Full Text Available Fourier transform infrared spectroscopy (FT-IR analysis was conducted on europium-doped hydroxyapatite, Ca10-xEux(PO46(OH2 nanocrystalline powders (Eu:HAp with 0≤xEu≤0.2. Antimicrobial studies were also performed for the first time on Eu:HAp. The antimicrobial properties of Eu:HAp nanoparticles with 0≤xEu≤0.2 on Gram-negative (E. coli ATCC 25922, Pseudomonas aeruginosa 1397 and Gram-positive (Staphylococcus aureus 0364, Enterococcus faecalis ATCC 29212 bacteria systems and a species of fungus (Candida albicans ATCC 10231 were reported. Our study demonstrates that the antimicrobial activity of Eu:HAp nanoparticles is dependent on the europium concentration.

Influence of Ag doping concentration on structural and optical properties of CdS thin film

International Nuclear Information System (INIS)

Kumar, Pragati; Saxena, Nupur; Gupta, Vinay; Agarwal, Avinash

2015-01-01

This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag 2 O or Ag 2 S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration

Influence of Ag doping concentration on structural and optical properties of CdS thin film

Energy Technology Data Exchange (ETDEWEB)

Kumar, Pragati, E-mail: pkumar.phy@gmail.com [Department of Physics, Bareilly College, Bareilly, 243 005, Uttar Pradesh (India); Department of Physics and Astrophysics, University of Delhi, Delhi, 110 007 (India); Saxena, Nupur; Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi, 110 007 (India); Agarwal, Avinash [Department of Physics, Bareilly College, Bareilly, 243 005, Uttar Pradesh (India)

2015-05-15

This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag{sub 2}O or Ag{sub 2}S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration.

Nanocrystalline electrodeposited Ni-Mo-C cathodes for hydrogen production

International Nuclear Information System (INIS)

Hashimoto, K.; Sasaki, T.; Meguro, S.; Asami, K.

2004-01-01

Tailoring active nickel alloy cathodes for hydrogen evolution in a hot concentrated hydroxide solution was attempted by electrodeposition. The carbon addition to Ni-Mo alloys decreased the nanocrystalline grain size and remarkably enhanced the activity for hydrogen evolution, changing the mechanism of hydrogen evolution. The Tafel slope of hydrogen evolution was about 35 mV per decade. This suggested that the rate-determining step is desorption of adsorbed hydrogen atoms by recombination. As was distinct from the binary Ni-Mo alloys, after open circuit immersion, the overpotential, that is, the activity of nanocrystalline Ni-Mo-C alloys for hydrogen evolution was not changed, indicating the sufficient durability in the practical electrolysis

p-type doping efficiency in CdTe: Influence of second phase formation

Science.gov (United States)

McCoy, Jedidiah J.; Swain, Santosh K.; Sieber, John R.; Diercks, David R.; Gorman, Brian P.; Lynn, Kelvin G.

2018-04-01

Cadmium telluride (CdTe) high purity, bulk, crystal ingots doped with phosphorus were grown by the vertical Bridgman melt growth technique to understand and improve dopant solubility and activation. Large net carrier densities have been reproducibly obtained from as-grown ingots, indicating successful incorporation of dopants into the lattice. However, net carrier density values are orders of magnitude lower than the solubility of P in CdTe as reported in literature, 1018/cm3 to 1019/cm3 [J. H. Greenberg, J. Cryst. Growth 161, 1-11 (1996) and R. B. Hall and H. H. Woodbury, J. Appl. Phys. 39(12), 5361-5365 (1968)], despite comparable starting charge dopant densities. Growth conditions, such as melt stoichiometry and post growth cooling, are shown to have significant impacts on dopant solubility. This study demonstrates that a significant portion of the dopant becomes incorporated into second phase defects as compounds of cadmium and phosphorous, such as cadmium phosphide, which inhibits dopant incorporation into the lattice and limits maximum attainable net carrier density in bulk crystals. Here, we present an extensive study on the characteristics of these second phase defects in relation to their composition and formation kinetics while providing a pathway to minimize their formation and enhance solubility.

An investigation into the room temperature mechanical properties of nanocrystalline austenitic stainless steels

International Nuclear Information System (INIS)

Eskandari, Mostafa; Zarei-Hanzaki, Abbas; Abedi, Hamid Reza

2013-01-01

Highlights: ► Strength of nanocrystalline specimens follows a trend of a remarkable rise along with a small drop in ductility in comparison to the coarse-grained one. ► Universal correlation of linear type (UTS = mτ max ) between shear punch test data and the tensile strength may be unreliable for the nanocrystalline materials. ► Actual relation between the maximum shear and ultimate tensile strength follows an empirical formula of UTS=0.013τ max 2 -25.62τ max +13049. -- Abstract: The present work has been conducted to evaluate the mechanical properties of nanostructured 316L and 301 austenitic stainless steels. The nanocrystalline structures were produced through martensite treatment which includes cold rolling followed by annealing treatment. The effect of equivalent rolling strain and annealing parameters on the room temperature mechanical behavior of the experimental alloys have been studied using the shear punch testing technique. The standard uniaxial tension tests were also carried out to adapt the related correlation factors. The microstructures and the volume fraction of phases were characterized by transmission electron microscopy and feritscopy methods, respectively. The results indicate that the strength of nanocrystalline specimens remarkably increases, but the ductility in comparison to the coarse-grained one slightly decreases. In addition the strength of nanocrystalline specimens has been increased by decreasing the annealing temperature and increasing the equivalent rolling strain. The analysis of the load–displacement data has also disclosed that the universal correlation of linear type (UTS = mτ max ) between shear punch test data and the tensile strength is somehow unreliable for the nanocrystalline materials. The results suggest that the actual relation between the maximum shear strength and ultimate tensile strength follows a second order equation of type UTS=aτ max 2 -bτ max +c.

Patterned hydrophobic and hydrophilic surfaces of ultra-smooth nanocrystalline diamond layers

Energy Technology Data Exchange (ETDEWEB)

Mertens, M., E-mail: michael.mertens@uni-ulm.de [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Mohr, M.; Brühne, K.; Fecht, H.J. [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Łojkowski, M.; Święszkowski, W. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Łojkowski, W. [Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw (Poland)

2016-12-30

Highlights: • Hydrophobic and hydrophilic properties on fluorine-, hydrogen- and oxygen- terminated ultra-nanocrystalline diamond films. • Micropatterned - multi-terminated layers with both hydrophobic and hydrophilic areas on one sample. • Visualization of multi-terminated surfaces by e.g. SEM and LFM. • Roughness and friction investigations on different terminated surfaces. • Smooth and biocompatible surfaces with same roughness regardless of hydrophobicity for microbiological investigations. - Abstract: In this work, we show that ultra nanocrystalline diamond (UNCD) surfaces have been modified to add them hydrophobic and hydrophilic properties. The nanocrystalline diamond films were deposited using the hot filament chemical vapor deposition (HFCVD) technique. This allows growing diamond on different substrates which can be even 3D or structured. Silicon and, for optical applications, transparent quartz glass are the preferred substrates for UNCD layers growth. Fluorine termination leads to strong hydrophobic properties as indicated by a high contact angle for water of more than 100°. Hydrogen termination shows lesser hydrophobic behavior. Hydrophilic characteristics has been realised with oxygen termination. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) measurements confirm the oxygen and fluorine- termination on the nanocrystalline diamond surface. Further, by micropatterning using photolithography, multi-terminated layers have been created with both hydrophobic and hydrophilic areas. In addition, we have shown that retermination is achieved, and the properties of the surface have been changed from hydrophobic to hydrophilic and vice versa. Micro- roughness and stress in the grown film influences slightly the wetting angle as well. The opportunity to realize local differences in hydrophobicity on nanocrystalline diamond layers, in any size or geometry, offers interesting applications for example in

Coexistence of short- and long-range ferromagnetic order in nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al (x=0.0, 0.1 and 0.3) synthesized by high-energy ball milling

Energy Technology Data Exchange (ETDEWEB)

Thanh, Tran Dang, E-mail: thanhxraylab@yahoo.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Nanto, Dwi [Physics Education, Syarif Hidayatullah States Islamic University, Jakarta 15412 (Indonesia); Tuyen, Ngo Thi Uyen [Department of Natural Science, Nha Trang Pedagogic College, Nguyen Chanh, Nha Trang, Khanh Hoa (Viet Nam); Nan, Wen-Zhe [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Yu, YiKyung [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Tartakovsky, Daniel M., E-mail: dmt@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Yu, S.C., E-mail: scyu@cbnu.ac.kr [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi (Viet Nam)

2015-11-15

In this work, we prepared nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al (x=0.0, 0.1 and 0.3) powders by the high energy ball milling technique, and then studied their critical properties. Our analysis reveals that the increase of Cu-doping concentration (up to x=0.3) in these powders leads to a gradual increase of the ferromagnetic–paramagnetic transition temperature from 406 to 452 K. The Banerjee criterion suggests that all the samples considered undergo a second-order phase transition. A modified Arrott plot and scaling analysis indicate that the critical exponents (β=0.419 and 0.442, γ=1.082 and 1.116 for x=0.0 and 0.1, respectively) are located in between those expected for the 3D-Heisenberg and the mean-field models; the values of β=0.495 and γ=1.046 for x=0.3 sample are very close to those of the mean-field model. These features reveal the coexistence of the short- and long-range ferromagnetic order in the nanocrystalline Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al powders. Particularly, as the concentration of Cu increases, values of the critical exponent shift towards those of the mean-field model. Such results prove the Cu doping favors establishing a long-range ferromagnetic order. - Highlights: • Fe{sub 2}Mn{sub 1−x}Cu{sub x}Al nanocrystals were prepared by a high energy ball milling method. • A coexistence of the short- and long-range FM order in the nanocrystals. • Cu doping favors establishing a long-range FM order in the nanocrystals. • All the ΔS{sub m}(T, H) data are followed a universal master curve.

An association between urinary cadmium and urinary stone disease in persons living in cadmium-contaminated villages in northwestern Thailand: A population study

International Nuclear Information System (INIS)

Swaddiwudhipong, Witaya; Mahasakpan, Pranee; Limpatanachote, Pisit; Krintratun, Somyot

2011-01-01

Excessive urinary calcium excretion is the major risk of urinary stone formation. Very few population studies have been performed to determine the relationship between environmental cadmium exposure and urinary stone disease. This population-based study examined an association between urinary cadmium excretion, a good biomarker of long-term cadmium exposure, and prevalence of urinary stones in persons aged 15 years and older, who lived in the 12 cadmium-contaminated villages in the Mae Sot District, Tak Province, northwestern Thailand. A total of 6748 persons were interviewed and screened for urinary cadmium and urinary stone disease in 2009. To test a correlation between urinary excretion of cadmium and calcium, we measured urinary calcium content in 1492 persons, who lived in 3 villages randomly selected from the 12 contaminated villages. The rate of urinary stones significantly increased from 4.3% among persons in the lowest quartile of urinary cadmium to 11.3% in the highest quartile. An increase in stone prevalence with increasing urinary cadmium levels was similarly observed in both genders. Multiple logistic regression analysis revealed a positive association between urinary cadmium levels and stone prevalence, after adjusting for other co-variables. The urinary calcium excretion significantly increased with increasing urinary cadmium levels in both genders, after adjusting for other co-variables. Elevated calciuria induced by cadmium might increase the risk of urinary stone formation in this environmentally exposed population. - Research highlights: → Excessive calciuria is the major risk of urinary stone formation. → We examine cadmium-exposed persons for urinary cadmium, calcium, and stones. → The rate of urinary stones increases with increasing urinary cadmium. → Urinary calcium excretion increases with increasing urinary cadmium. → Elevated calciuria induced by cadmium may increase the risk of urinary stones.

Influence of grain boundaries on elasticity and thermal conductivity of nanocrystalline diamond films

International Nuclear Information System (INIS)

Mohr, Markus; Daccache, Layal; Horvat, Sebastian; Brühne, Kai; Jacob, Timo; Fecht, Hans-Jörg

2017-01-01

Diamond combines several outstanding material properties such as the highest thermal conductivity and highest elastic moduli of all materials. This makes diamond an interesting candidate for a multitude of applications. Nonetheless, nanocrystalline diamond films, layers and coatings, usually show properties different to those of single crystalline diamond. This is usually attributed to the larger volume fraction of the grain boundaries with atomic structure different from the single crystal. In this work we measured Young's modulus and thermal conductivity of nanocrystalline diamond films with average grain sizes ranging from 6 to 15 nm. The measured thermal conductivities are modeled considering the thermal boundary conductance between grains as well as a grain size effect on the phonon mean free path. We make a comparison between elastic modulus and thermal boundary conductance of the grain boundaries G_k for different nanocrystalline diamond films. We conclude that the grain boundaries thermal boundary conductance G_k is a measure of the cohesive energy of the grain boundaries and therefore also of the elastic modulus of the nanocrystalline diamond films.

Structure and high photocatalytic activity of (N, Ta)-doped TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Le, N. T. H.; Lam, V. D.; Manh, D. H.; Hong, L. V. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Thanh, T. D., E-mail: thanhxraylab@yahoo.com, E-mail: scyu@cbnu.ac.kr [Institute of Materials Science, Vietnam Academy of Science and Technology, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Pham, V.-T. [Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Synchrotron SOLEIL, L' Orme des Merisiers, Boîte Postale, 48, 91192 Gif-sur-Yvette Cedex (France); Phan, T. L.; Yu, S. C., E-mail: thanhxraylab@yahoo.com, E-mail: scyu@cbnu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Anh, T. X. [Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi (Viet Nam); Le, T. K. C. [Institut des Sciences Moleculaires d' Orsay, CNRS, Univ Paris-Sud, 91405 Orsay Cedex (France); Thammajak, N. [Synchrotron Light Research Institute, 111 University Avenue, Muang, Nakhon Ratchasima 30000 (Thailand)

2016-10-14

A hydrothermal method was used to prepare three nano-crystalline samples of TiO{sub 2} (S1), N-doped TiO{sub 2} (S2), and (N, Ta)-codoped TiO{sub 2} (S3) with average crystallite sizes (D) of 13–25 nm. X-ray diffraction studies confirmed a single phase of the samples with a tetragonal/anatase structure. A slight increase in the lattice parameters was observed when N and/or Ta dopants were doped into the TiO{sub 2} host lattice. Detailed analyses of extended X-ray absorption spectra indicated that N- and/or Ta-doping into TiO{sub 2} nanoparticles influenced the co-ordination number and radial distance (R) of Ti ions in the anatase structure. Concerning their absorption spectra, (N, Ta)-doping narrowed the band gap (E{sub g}) of TiO{sub 2} from 3.03 eV for S1 through 2.94 eV for S2 to 2.85 eV for S3. Such results revealed the applicability of these nanoparticles in the photocatalytic field working in the ultraviolet (UV)-visible region. Among these, photocatalytic activity of S3 was the strongest. By using S3 as a catalyst powder, the degradation efficiency of methylene blue solution was about 99% and 93% after irradiation of UV-visible light for 75 min and visible-light for 180 min, respectively.

Isolation of bacterial cellulose nanocrystalline from pineapple peel waste: Optimization of acid concentration in the hydrolysis method

Science.gov (United States)

Anwar, Budiman; Rosyid, Nurul Huda; Effendi, Devi Bentia; Nandiyanto, Asep Bayu Dani; Mudzakir, Ahmad; Hidayat, Topik

2016-02-01

Isolation of needle-shaped bacterial cellulose nanocrystalline with a diameter of 16-64 nm, a fiber length of 258-806 nm, and a degree of crystallinity of 64% from pineapple peel waste using an acid hydrolysis process was investigated. Experimental showed that selective concentration of acid played important roles in isolating the bacterial cellulose nanocrystalline from the cellulose source. To achieve the successful isolation of bacterial cellulose nanocrystalline, various acid concentrations were tested. To confirm the effect of acid concentration on the successful isolation process, the reaction conditions were fixed at a temperature of 50°C, a hydrolysis time of 30 minutes, and a bacterial cellulose-to-acid ratio of 1:50. Pineapple peel waste was used as a model for a cellulose source because to the best of our knowledge, there is no report on the use of this raw material for producing bacterial cellulose nanocrystalline. In fact, this material can be used as an alternative for ecofriendly and cost-free cellulose sources. Therefore, understanding in how to isolate bacterial cellulose nanocrystalline from pineapple peel waste has the potential for large-scale production of inexpensive cellulose nanocrystalline.

Formation of ZnO Nanocrystalline via Facile Non-Hydrolytic Route

International Nuclear Information System (INIS)

Ooi, M. D. Johan; Aziz, A. Abdul; Abdullah, M. J.

2011-01-01

Zinc oxide (ZnO) nanocrystalline were synthesized via oxidizing Zn powder in non-aqueous solvent with addition of Diethanolamine (DEA) as a stabilizing agent. The influence of DEA on the structural, optical properties and the formation of ZnO nanocrystalline were studied. The synthesized ZnO were polycrystalline in structures where sample without the addition of DEA shows high intensity peak of (002) phase compared with sample in the presence of DEA which preferred to grow in (101) direction. SEM micrograph displays the morphology of ZnO nanocrystalline for both of the samples which shows micron size and non-uniform particles for sample without DEA whereas for sample with DEA exhibit smaller size (∼110 nm) and nearly spherical in shape despite of some agglomeration occurs at the interparticle separation. The photoluminescence (PL) spectra shows UV emission peak for both of the samples where sample with the absence of DEA possess lower intensity of UV emission peak compared to samples with DEA which demonstrate stronger intensity despite of having very weak visible secondary emission peak at 530 nm.

Grain size dependent electrical studies on nanocrystalline SnO2

International Nuclear Information System (INIS)

Bose, A. Chandra; Thangadurai, P.; Ramasamy, S.

2006-01-01

Nanocrystalline tin oxide (n-SnO 2 ) with different grain sizes were synthesized by chemical precipitation method. Size variation was achieved by changing the hydrolysis processing time. Structural phases of the nanocrystalline SnO 2 were identified by X-ray diffraction (XRD). The grain sizes of the prepared n-SnO 2 were found to be in the range 5-20 nm which were estimated using the Scherrer formula and they were confirmed by transmission electron microscopy (TEM) measurements. The electrical properties of nanocrystalline SnO 2 were studied using impedance spectroscopy. The impedance spectroscopy results showed that, in the temperature range between 25 and 650 deg. C, the conductivity has contributions from two different mechanisms, which are attributed to different conduction mechanisms in the grain and the grain boundary regions. This is because of the different relaxation times available for the conduction species in those regions. However, for the temperatures above 300 deg. C, there is no much difference between these two different relaxation times. The Arrhenius plots gave the activation energies for the conduction process in all the samples

Grain size refinement in nanocrystalline Hitperm-type glass-coated microwires

International Nuclear Information System (INIS)

Talaat, A.; Val, J.J. del; Zhukova, V.; Ipatov, M.; Klein, P.; Varga, R.; González, J.; Churyukanova, M.; Zhukov, A.

2016-01-01

We present a new-Fe 38.5 Co 38.5 B 18 Mo 4 Cu 1 Hitperm glass-coated microwires obtained by Taylor-Ulitovsky technique with nanocrystalline structure consisting of about 23 nm of BCC α-FeCo and an amorphous precursors in as-prepared samples. Annealing resulted in a considerable decrease of such nano-grains down to (11 nm). Obtained results are discussed in terms of the stress diffusion of limited crystalline growth and the chemical composition. Rectangular hysteresis loops have been observed on all annealed samples that are necessary conditions to obtain fast domain wall propagation. An enhancement of the domain wall velocity as well as mobility after annealing has been obtained due to the structural relaxation of such grains with positive magnetostriction. These structure benefits found in the nanocrystalline Hitperm glass-coated microwires are promising for developing optimal magnetic properties. - Highlights: • Grains size refinement upon annealing. • Enhancement of the domain wall velocity as well as mobility after annealing. • Nanocrystalline structure in as-prepared microwires.

Light trapping of crystalline Si solar cells by use of nanocrystalline Si layer plus pyramidal texture

Energy Technology Data Exchange (ETDEWEB)

Imamura, Kentaro; Nonaka, Takaaki; Onitsuka, Yuya; Irishika, Daichi; Kobayashi, Hikaru, E-mail: h.kobayashi@sanken.osaka-u.ac.jp

2017-02-15

Highlights: • Ultralow reflectivity Si wafers with light trapping effect can be obtained by forming a nanocrystalline Si layer on pyramidal textured Si surfaces. • Surface passivation using phosphosilicate glass improved minority carrier lifetime of the nanocrystalline Si layer/Si structure. • A high photocurrent density of 40.1 mA/cm{sup 2}, and a high conversion efficiency of 18.5% were achieved. - Abstract: The surface structure chemical transfer (SSCT) method has been applied to fabrication of single crystalline Si solar cells with 170 μm thickness. The SSCT method, which simply involves immersion of Si wafers in H{sub 2}O{sub 2} plus HF solutions and contact of Pt catalyst with Si taking only ∼30 s for 6 in. wafers, can decrease the reflectivity to less than 3% by the formation of a nanocrystalline Si layer. However, the reflectivity of the nanocrystalline Si layer/flat Si surface/rear Ag electrode structure in the wavelength region longer than 1000 nm is high because of insufficient absorption of incident light. The reflectivity in the long wavelength region is greatly decreased by the formation of the nanocrystalline Si layer on pyramidal textured Si surfaces due to an increase in the optical path length. Deposition of phosphosilicate glass (PSG) on the nanocrystalline Si layer for formation of pn-junction does not change the ultralow reflectivity because the surface region of the nanocrystalline Si layer possesses a refractive index of 1.4 which is nearly the same as that of PSG of 1.4–1.5. The PSG layer is found to passivate the nanocrystalline Si layer, which is evident from an increase in the minority carrier lifetime from 12 to 44 μs. Hydrogen treatment at 450 °C further increases the minority carrier lifetime approximately to a doubled value. The solar cells with the nanocrystalline Si layer/pyramidal Si substrate/boron-diffused back surface field/Ag rear electrode> structure show a high conversion efficiency of 18

Cadmium induced changes in cell organelles: An ultrastructural study using cadmium sensitive and resistant muntjac fibroblast cell lines

Energy Technology Data Exchange (ETDEWEB)

Ord, M.J.; Chibber, R.; Bouffler, S.D.

1988-09-01

A detailed electron microscopy study of cadmium sensitive and resistant muntjac fibroblast cell lines has identified a wide range of intracellular damage following exposure to cadmium. Damaged organelles included cell membrane, mitochondria, Golgi cisternae and tubular network, chromatin, nucleoli, microfilaments and ribosomes. Although cell membrane damage was generally the earliest indication of adverse cadmium action, particularly with continuous cadmium exposures, cells could tolerate extensive membrane loss. Mitochondrial distortion and some damage to Golgi was also tolerated. The turning point at which cadmium became lethal was generally marked by a cascade of events which included damage to both nuclear and cytoplasmic components. These results for fibroblasts are discussed and compared with damage reported in other types of cells.

Self-composite comprised of nanocrystalline diamond and a non-diamond component useful for thermoelectric applications

Science.gov (United States)

Gruen, Dieter M [Downers Grove, IL

2009-08-11

One provides nanocrystalline diamond material that comprises a plurality of substantially ordered diamond crystallites that are sized no larger than about 10 nanometers. One then disposes a non-diamond component within the nanocrystalline diamond material. By one approach this non-diamond component comprises an electrical conductor that is formed at the grain boundaries that separate the diamond crystallites from one another. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also preserving the thermal conductivity behavior of the nanocrystalline diamond material.

Detecting spin polarization of nano-crystalline manganese doped zinc oxide thin film using circular polarized light

Energy Technology Data Exchange (ETDEWEB)

El-Sayed, H.M., E-mail: h_m_elsaid@hotmail.com

2016-02-01

The presence of spin polarization in Mn-doped ZnO thin film is very important for spintronic applications. Spin polarization was detected using simple method. This method depends on measuring the optical transmittance using circular polarized light in visible and near infra-red region. It was found that, there is a difference in the optical energy gap of the film for circular left and circular polarized light. For temperatures > 310 K the difference in energy gap is vanished. This result is confirmed by measuring the magnetic hysteresis of the film. This work introduces a promising method for measuring the ferromagnetism in diluted magnetic semiconductors. - Highlights: • Highly oriented c-axis of Mn-ZnO thin film doped with nitrogen is prepared. • The optical energy gap depends on the state of circularly polarized light. • The presence of spin polarization is confirmed using simple optical method. • Magnetic measurements are consistent with the results of the optical method.

Molecular and cellular mechanisms of cadmium carcinogenesis

International Nuclear Information System (INIS)

Waisberg, Michael; Joseph, Pius; Hale, Beverley; Beyersmann, Detmar

2003-01-01

Cadmium is a heavy metal, which is widely used in industry, affecting human health through occupational and environmental exposure. In mammals, it exerts multiple toxic effects and has been classified as a human carcinogen by the International Agency for Research on Cancer. Cadmium affects cell proliferation, differentiation, apoptosis and other cellular activities. Cd 2+ does not catalyze Fenton-type reactions because it does not accept or donate electrons under physiological conditions, and it is only weakly genotoxic. Hence, indirect mechanisms are implicated in the carcinogenicity of cadmium. In this review multiple mechanisms are discussed, such as modulation of gene expression and signal transduction, interference with enzymes of the cellular antioxidant system and generation of reactive oxygen species (ROS), inhibition of DNA repair and DNA methylation, role in apoptosis and disruption of E-cadherin-mediated cell-cell adhesion. Cadmium affects both gene transcription and translation. The major mechanisms of gene induction by cadmium known so far are modulation of cellular signal transduction pathways by enhancement of protein phosphorylation and activation of transcription and translation factors. Cadmium interferes with antioxidant defense mechanisms and stimulates the production of reactive oxygen species, which may act as signaling molecules in the induction of gene expression and apoptosis. The inhibition of DNA repair processes by cadmium represents a mechanism by which cadmium enhances the genotoxicity of other agents and may contribute to the tumor initiation by this metal. The disruption of E-cadherin-mediated cell-cell adhesion by cadmium probably further stimulates the development of tumors. It becomes clear that there exist multiple mechanisms which contribute to the carcinogenicity of cadmium, although the relative weights of these contributions are difficult to estimate

Cadmium in the bioenergy system - a synthesis

International Nuclear Information System (INIS)

Ahlfont, K.

1997-12-01

Cadmium is a toxic metal without any known positive biological effects. Both emissions and atmospheric deposition of cadmium have decreased radically in Sweden during recent years. In Sweden, about 150 tonnes of cadmium was supplied to the technosphere in 1990, mostly originating from NiCd batteries. More than 100 tonnes of cadmium accumulated in the technosphere. Mankind takes up cadmium from water, food and particulate atmospheric pollution. Even small amounts may be injurious in the long-term since the half-life in the kidneys is 30 years. Cadmium in biofuel and ashes are generally a cause of discussion. Ashes from biofuel constitute a nutrient resource that should be returned to the soil. A possible risk with spreading ashes is the spreading of heavy metals, and then foremost cadmium, which is among the heavy metals that forest soils are considered to tolerate the least. Several studies on cadmium in the bioenergy system have been made, both within the Research Programme for Recycling of Wood-ash, and within Vattenfall's Bioenergy Project. The present report is intended to provide a picture of the current state of knowledge and to review plans for the future With a 3 page summary in English. 51 refs, 1 fig, 3 tabs

Association of urinary cadmium and myocardial infarction

International Nuclear Information System (INIS)

Everett, Charles J.; Frithsen, Ivar L.

2008-01-01

We conducted a cross-sectional analysis of individuals 45-79 years old in the National Health and Nutrition Examination Survey III (1988-1994) (NHANES III). Myocardial infarction was determined by electrocardiogram (ECG). Our sample included 4912 participants, which when weighted represented 52,234,055 Americans. We performed adjusted logistic regressions with the Framingham risk score, pack-years of smoking, race-ethnicity, and family history of heart attack, and diabetes as covariates. Urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.86 (95% CI 1.26-2.75) compared to urinary cadmium <0.43 μg/g creatinine. This result supports the hypothesis that cadmium is associated with coronary heart disease. When logistic regressions were done by gender, women, but not men, showed a significant association of urinary cadmium with myocardial infarction. Women with urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.80 (95% CI 1.06-3.04) compared to urinary cadmium <0.43 μg/g creatinine. When the analysis was restricted to never smokers (N=2187) urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.85 (95% CI 1.10-3.14) compared to urinary cadmium <0.43 μg/g creatinine

Cadmium action in synapses in the brain

International Nuclear Information System (INIS)

Minami, Akira; Takeda, Atsushi; Nishibaba, Daisuke; Tekefuta, Sachiyo; Oku, Naoto

2001-01-01

Chronic exposure to cadmium causes central nervous system disorders, e.g., olfactory dysfunction. To clarify cadmium toxicity in synaptic neurotransmission in the brain, the movement and action of cadmium in the synapses was examined using in vivo microdialysis. One and 24 h after injection of 109 CdCl 2 into the amygdala of rats, 109 Cd release into the extracellular space was facilitated by stimulation with high K + , suggesting that cadmium taken up in amygdalar neurons is released into the synaptic clefts in a calcium- and impulse-dependent manner. To examine the action of cadmium in the synapses, the amygdala was perfused with artificial cerebrospinal fluid containing 10-30 μM CdCl 2 . The release of excitatory neurotransmitters, i.e., glutamate and aspartate, into the extracellular space was decreased during perfusion with cadmium, while the release of inhibitory neurotransmitters, i.e., glycine and γ-amino butyric acid (GABA), into the extracellular space was increased during the period. These results suggest that cadmium released from the amygdalar neuron terminals affects the degree and balance of excitation-inhibition in synaptic neurotransmission. (author)

Ultrafine Nanocrystalline CeO2@C-Containing NaAlH4 with Fast Kinetics and Good Reversibility for Hydrogen Storage.

Science.gov (United States)

Zhang, Xin; Liu, Yongfeng; Wang, Ke; Li, You; Gao, Mingxia; Pan, Hongge

2015-12-21

A nanocrystalline CeO2@C-containing NaAlH4 composite is successfully synthesized in situ by hydrogenating a NaH-Al mixture doped with CeO2@C. Compared with NaAlH4 , the as-prepared CeO2@C-containing NaAlH4 composite, with a minor amount of excess Al, exhibits significantly improved hydrogen storage properties. The dehydrogenation onset temperature of the hydrogenated [NaH-Al-7 wt % CeO2@C]-0.04Al sample is 77 °C lower than that of the pristine sample because of a reduced kinetic barrier. More importantly, the dehydrogenated sample absorbs ∼4.7 wt % hydrogen within 35 min at 100°C and 10 MPa of hydrogen. Compositional and structural analyses reveal that CeO2 is converted to CeH2 during ball milling and that the newly formed CeH2 works with the excess of Al to synergistically improve the hydrogen storage properties of NaAlH4. Our findings will aid in the rational design of novel catalyst-doped complex hydride systems with low operating temperatures, fast kinetics, and long-term cyclability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distribution of cadmium between calcium carbonate and solution, 2

International Nuclear Information System (INIS)

Kitano, Yasushi; Kanamori, Nobuko; Fujiyoshi, Ryoko

1978-01-01

The distribution coefficient of cadmium between calcite and solution has been measured in the calcium bicarbonate solution containing cadmium and chloride ions, which forms complexes with cadmium ions. It has been confirmed experimentally that cadmium carbonate is present as a solid solution between calcitic calcium carbonate and cadmium carbonate in the carbonate precipitate formed in the solution system. However, the constant value of the thermodynamic distribution coefficient of cadmium between calcite and solution has not been obtained experimentally in the calcium bicarbonate solution containing cadmium and chloride ions. It may have been caused by the very specific behavior of cadmium ions, but the exact reason remains unsolved and must be studied. (Kobatake, H.)

Synthesis and luminescence properties of nanocrystalline LiF:Mg,Cu,P phosphor

Energy Technology Data Exchange (ETDEWEB)

Sahare, P.D., E-mail: pdsahare@physics.du.ac.i [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Bakare, J.S. [SSGM College of Engineering, Amravati University, Shegaon 444 203, Maharashtra (India); Dhole, S.D. [Department of Physics, University of Pune, Ganeshkhind, Pune 411 007 (India); Ingale, N.B. [Department of Physics, Professor Ram Meghe Institute of Technology and Research, Badnera-Amravati 444 605, Maharashtra (India); Rupasov, A.A. [P. N. Lebedev Physical Institute, Russian Academy of Sciences, Leninsky pr-t 53, Moscow (Russian Federation)

2010-02-15

Nanocrystalline LiF:Mg,Cu,P phosphor material of different shapes and sizes (microcrystalline cubic shape, nanorod shape and nanocrystalline cubical shaped) have been prepared by the chemical co-precipitation method. Thermoluminescence (TL) and other dosimetric characteristics of the phosphor are studied and presented here. The formation of the materials was confirmed by the X-ray diffraction (XRD). Its shapes and sizes were also observed using scanning electron microscope (SEM). The TL glow curve of the microcrystalline powder shows a prominent single peak at 408 K along with another peak of lesser intensity at around 638 K. On the contrary, the nanocrystalline rod shaped particles show a peak of low intensity at 401 K and a prominent peak around 700 K while the nanocrystalline particles in cubical shapes again show two peaks, one at around 407 K and the other at around 617 K, of which the lower temperature (407 K) peak is more prominent. The glow curve structure changes at very high doses (100 kRad) and some new peaks appear at around 525 and 637 K also the first peak appearing at around 401 K becomes prominent. The observed changes in TL due to the change in the shape and sizes of the nanophosphor have been reported. The PL has also been studied and various excitation and emission peaks observed due to the presence of various impurities are explained. The observed results have been explained in the light of asymmetrical crystal field effects due to asymmetrical shapes of the nanocrystalline phosphor. The comparison of these properties with the microcrystalline material prepared by the same co-precipitation method is also done.

Formation of nanocrystalline TiC from titanium and different carbon sources by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Jia Haoling [Key Lab of Liquid Structure and Heredity of Materials, Jingshi Road 73, Jinan 250061, Shandong (China); Zhang Zhonghua [Key Lab of Liquid Structure and Heredity of Materials, Jingshi Road 73, Jinan 250061, Shandong (China)], E-mail: zh_zhang@sdu.edu.cn; Qi Zhen [Key Lab of Liquid Structure and Heredity of Materials, Jingshi Road 73, Jinan 250061, Shandong (China); Liu Guodong [School of Materials Science and Engineering, Shandong University, Jingshi Road 73, Jinan 250061 (China); Bian Xiufang [Key Lab of Liquid Structure and Heredity of Materials, Jingshi Road 73, Jinan 250061, Shandong (China)

2009-03-20

In this paper, the formation of nanocrystalline TiC from titanium powders and different carbon resources by mechanical alloying (MA) has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The experimental results show that nanocrystalline TiC can be synthesized from Ti powders and different carbon resources (activated carbon, carbon fibres or carbon nanotubes) by MA at room temperature. Titanium and different carbon resources have a significant effect on the Ti-C reaction and the formation of TiC during MA. Moreover, the formation of nanocrystalline TiC is governed by a gradual diffusion reaction mechanism during MA, regardless of different carbon resources.

Effect of iron content on permeability and power loss characteristics ...

Indian Academy of Sciences (India)

Administrator

have been measured by vibrating sample magnetometer (VSM). The permeability of cadmium doped lithium ferrites exhibited higher values than zinc doped lithium ferrites. The power loss of cadmium doped lithium ferrites is lesser as compared to zinc doped lithium ferrites in the frequency range of 50–5000 kHz and at flux.

Powder-based synthesis of nanocrystalline material components for structural application. Final report

Energy Technology Data Exchange (ETDEWEB)

Ilyuschenko, A.F.; Ivashko, V.S.; Okovity, V.A. [Powder Metallurgy Research Inst., Minsk (Belarus)] [and others

1998-12-01

Hydroxiapate spray coatings and substrates for implant production as well as multilayered metal ceramic coatings from nanocrystalline materials are a subject of the investigation. The work aims at the improvement of quality of said objects. This study has investigated the processes of hydroxiapatite powder production. Sizes, shapes and relief of initial HA powder surface are analyzed using SEM and TEM. Modes of HA plasma spraying on a substrate from titanium and associated compositions of traditional and nanocrystalline structure are optimized. The quality of the sprayed samples are studied using X-ray phase analysis and metallographic analysis. The results of investigations of bioceramic coating spraying on titanium are theoretically generalized, taking into account obtained experimental data. The results of investigations of ion-beam technology are presented for spraying multilayered coatings consisting of alternating metal-ceramic layers of nanocrystalline structure.

Correlations of urinary cadmium with hypertension and diabetes in persons living in cadmium-contaminated villages in northwestern Thailand: A population study

Energy Technology Data Exchange (ETDEWEB)

Swaddiwudhipong, Witaya, E-mail: swaddi@hotmail.com [Department of Community and Social Medicine, Mae Sot General Hospital, Tak 63110 (Thailand); Mahasakpan, Pranee [Department of Community and Social Medicine, Mae Sot General Hospital, Tak 63110 (Thailand); Limpatanachote, Pisit; Krintratun, Somyot [Department of Internal Medicine, Mae Sot General Hospital, Tak (Thailand)

2010-08-15

Risk for hypertension and diabetes has not been conclusively found to be a result of cadmium exposure. A population-based study was conducted in 2009 to examine the correlations of urinary cadmium, a good biomarker of long-term cadmium exposure, with hypertension and diabetes in persons aged 35 years and older who lived in the 12 cadmium-contaminated rural villages in northwestern Thailand. A total of 5273 persons were interviewed and screened for urinary cadmium, hypertension, and diabetes. The geometric mean level of urinary cadmium for women (2.4{+-}2.3 {mu}g/g creatinine) was significantly greater than that for men (2.0{+-}2.2 {mu}g/g creatinine). Hypertension was presented in 29.8% of the study population and diabetes was detected in 6.6%. The prevalence of hypertension significantly increased from 25.0% among persons in the lowest tertile of urinary cadmium to 35.0% in the highest tertile. In women, the rate of hypertension significantly increased with increasing urinary cadmium levels in both ever and never smokers, after adjusting for age, alcohol consumption, body mass index, and diabetes. In men, such association was less significantly found in never smokers. The study revealed no significant association between urinary cadmium and diabetes in either gender. Our study supports the hypothesis that environmental exposure to cadmium may increase the risk of hypertension. Risk for diabetes in relation to cadmium exposure remains uncertain in this exposed population.

Correlations of urinary cadmium with hypertension and diabetes in persons living in cadmium-contaminated villages in northwestern Thailand: A population study

International Nuclear Information System (INIS)

Swaddiwudhipong, Witaya; Mahasakpan, Pranee; Limpatanachote, Pisit; Krintratun, Somyot

2010-01-01

Risk for hypertension and diabetes has not been conclusively found to be a result of cadmium exposure. A population-based study was conducted in 2009 to examine the correlations of urinary cadmium, a good biomarker of long-term cadmium exposure, with hypertension and diabetes in persons aged 35 years and older who lived in the 12 cadmium-contaminated rural villages in northwestern Thailand. A total of 5273 persons were interviewed and screened for urinary cadmium, hypertension, and diabetes. The geometric mean level of urinary cadmium for women (2.4±2.3 μg/g creatinine) was significantly greater than that for men (2.0±2.2 μg/g creatinine). Hypertension was presented in 29.8% of the study population and diabetes was detected in 6.6%. The prevalence of hypertension significantly increased from 25.0% among persons in the lowest tertile of urinary cadmium to 35.0% in the highest tertile. In women, the rate of hypertension significantly increased with increasing urinary cadmium levels in both ever and never smokers, after adjusting for age, alcohol consumption, body mass index, and diabetes. In men, such association was less significantly found in never smokers. The study revealed no significant association between urinary cadmium and diabetes in either gender. Our study supports the hypothesis that environmental exposure to cadmium may increase the risk of hypertension. Risk for diabetes in relation to cadmium exposure remains uncertain in this exposed population.

Stability of charge and orbital order in half-doped Y{sub 0.5}Ca{sub 0.5}MnO{sub 3} nanocrystallites

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Putul Malla, E-mail: putularun@gmail.com; Ghosh, Barnali, E-mail: barnali@bose.res.in; Raychaudhuri, A. K., E-mail: arup@bose.res.in [S N Bose National Centre for Basic Sciences, Unit for Nano Science, Department of Condensed Matter Physics and Materials Science (India); Kaushik, S. D.; Siruguri, V. [UGC-DAE Consortium for Scientific Research Mumbai Centre, R-5 Shed, Bhabha Atomic Research Centre (India)

2013-04-15

In this paper, we report a detailed study of the structure, magnetic, and electrical transport properties in nanocrystallites of hole-doped manganite Y{sub 0.5}Ca{sub 0.5}MnO{sub 3}, with the aim to study the effect of size reduction on the stability of the charge-orbital order and the antiferromagnetic spin order that are seen in the bulk samples of the half-doped manganite. The investigations have been done in the general context of investigating how size reduction affects competing interactions in complex oxides and thus, changes their ground state. The bulk sample of the material (average crystallite size {approx}1 {mu}m), with the smallest radius of the cation in A-site (Y), shows a robust charge and orbital ordered insulating state below the transition temperature near 290 K and an antiferromagnetic spin order at 110 K. The experiments carried out on well-characterized nanocrystalline samples, with average crystallite sizes down to 75 nm, establish that the size reduction changes the structural parameters, and the charge and orbital ordering are suppressed. However, the antiferromagnetic spin order (as revealed by neutron diffraction experiments carried out down to 2 K) persists in the nanocrystallites and co-exists with ferromagnetic order below 110 K. The nanocrystalline samples have significant lower resistivities (by few orders) compared to those of the bulk samples in the temperature range 10-300 K. This corroborates the formation of the ferromagnetic moments in the nanocrystallites.

Novel Cadmium Resistance Determinant in Listeria monocytogenes.

Science.gov (United States)

Parsons, Cameron; Lee, Sangmi; Jayeola, Victor; Kathariou, Sophia

2017-03-01

Listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables Listeria to tolerate exposure to cadmium is the cadAC efflux system, with CadA being a P-type ATPase. Three different cadA genes (designated cadA1 to cadA3 ) were previously characterized in L. monocytogenes A novel putative cadmium resistance gene ( cadA4 ) was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking. In this study, we characterized cadA4 in L. monocytogenes strain F8027, a cadmium-resistant strain of serotype 4b. By screening a mariner-based transposon library of this strain, we identified a mutant with reduced tolerance to cadmium and that harbored a single transposon insertion in cadA4 The tolerance to cadmium was restored by genetic complementation with the cadmium resistance cassette ( cadA4C ), and enhanced cadmium tolerance was conferred to two unrelated cadmium-sensitive strains via heterologous complementation with cadA4C Cadmium exposure induced cadA4 expression, even at noninhibitory levels. Virulence assessments in the Galleria mellonella model suggested that a functional cadA4 suppressed virulence, potentially promoting commensal colonization of the insect larvae. Biofilm assays suggested that cadA4 inactivation reduced biofilm formation. These data not only confirm cadA4 as a novel cadmium resistance determinant in L. monocytogenes but also provide evidence for roles in virulence and biofilm formation. IMPORTANCE Listeria monocytogenes is an intracellular foodborne pathogen causing the disease listeriosis, which is responsible for numerous hospitalizations and deaths every year. Among the adaptations that enable the survival of Listeria in the environment are the abilities to persist in biofilms, grow in the cold, and

Modelling of cadmium fluxes on energy crop land

International Nuclear Information System (INIS)

Palm, V.

1992-04-01

The flux of cadmium on energy crop land is investigated. Three mechanisms are accounted for; Uptake by plant, transport with water, and sorption to soil. Sorption is described with Freundlich isotherms. The system is simulated mathematically in order to estimate the sensitivity and importance of different parameters on the cadmium flow and sorption. The water flux through the soil and the uptake by plants are simulated with a hydrological model, SOIL. The simulated time period is two years. The parameters describing root distribution and evaporation due to crop are taken from measurements on energy crop (Salix). The resulting water flux, water content in the soil profile and the water uptake into roots, for each day and soil compartment, are used in the cadmium sorption simulation. In the cadmium sorption simulation the flux and equilibrium chemistry of cadmium is calculated. It is shown that the amount of cadmium that accumulates in the plant, and the depth to which the applied cadmium reaches depends strongly on the constants in the sorption isotherm. With an application of 10 mg Cd/m 2 in the given range of Freundlich equations, the simulations gave a plant uptake of between 0 and 30 % of the applied cadmium in two years. At higher concentrations, where cadmium sorption can be described by nonlinear isotherms, more cadmium is present in soil water and is generally more bioavailable. 25 refs

Structural, optical and gas sensing properties of screen-printed nanostructured Sr-doped SnO2 thick film sensor

International Nuclear Information System (INIS)

Shaikh, F.I.; Chikhale, L.P.; Patil, J.Y.; Rajgure, A.V.; Suryavanshi, S.S.; Mulla, I.S.

2013-01-01

The nanocrystalline materials of strontium doped tin oxide powders were synthesized by conventional co-precipitation method. Synthesized nanophase SnO 2 powders were used to fabricate thick films of pure and Sr-doped SnO 2 using screen-printing technology and investigated for their gas sensing properties towards LPG, ethanol, ammonia and acetone vapor. The crystal structure and phase of the sintered powders were characterized by X-ray diffractometer (XRD) and microstructure by scanning electron microscopy (SEM). All the doped and undoped SnO 2 compositions revealed single phase and solid solution formation. X-ray diffractometer (XRD) results indicated that well crystallized Sr-doped SnO 2 particles of size about 10 nm were obtained at sintering temperature 700℃. The optical properties viz. UV-Vis, FTIR and Raman were used to characterize various physico-chemical properties of samples. The reduction of grain size in metal oxide is a key factor to enhance the gas sensing properties. The doping of Sr in SnO 2 has reduced the grain size and improved the gas response. The results of gas sensing measurements showed that the thick films deposited on alumina substrates using screen-printing technique exhibited high gas response, quick response time and fast recovery time to acetone gas at a working temperature of 250℃. Further, the selectivity of sensor towards acetone with respect to other reducing gases (LPG, ethanol, ammonia) was studied. (author)

Zinc-induced protection against cadmium

Energy Technology Data Exchange (ETDEWEB)

Early, J.L.; Schnell, R.C.

1978-02-01

Pretreatment of male rats with cadmium acetate potentiates the duration of hexobarbital hypnosis and inhibits the rate of hepatic microsomal drug metabolism. Pretreatment of rats with zinc acetate protects against these alterations in drug action elicited by cadmium.

Synthesis and characterization of nano- and microcrystalline cubes of pure and Ag-doped LiF

Science.gov (United States)

Alharbi, Najlaa D.; Salah, Numan; Habib, Sami S.; Alarfaj, Esam

2013-01-01

Lithium fluoride (LiF) produced in single crystals and doped with proper activators is a highly sensitive phosphor used in several applications such as integrated optics, colour centre laser and radiation dosimetry. In this work, we have developed a new synthetic chemical co-precipitation route for the synthesis of well-crystallized micro- and nanocrystalline cubes of pure and silver (Ag)-doped LiF. The as-synthesized samples were characterized by x-ray diffraction (XRD), scanning electron microscopy, absorption spectrum, photoluminescence (PL) and Raman spectroscopy. Size of the produced cubes could be controlled in the range 10 µm-50 nm by varying the solvent : co-solvent ratio. Micro-sized cubes could be grown in the presence of water as a solvent, while ethanol, which acts as a co-solvent, is found to be effective in reducing the size to the nanoscale. XRD results show complete crystalline structures in a griceite phase. The PL result of pure nanocubes exhibits a broad band in the range 370-550 nm, while that doped with Ag shows a prominent band at 420 nm. Raman spectra of the pure and Ag-doped LiF samples display several bands located in the range 80-236 cm-1. These results show that pure nanocubes of LiF have active colour centres without irradiation, which could be enhanced/modified by Ag dopants. This implies that these nanocubes might be useful in the development of optical devices.

Synthesis and characterization of nano- and microcrystalline cubes of pure and Ag-doped LiF

International Nuclear Information System (INIS)

Alharbi, Najlaa D; Salah, Numan; Habib, Sami S; Alarfaj, Esam

2013-01-01

Lithium fluoride (LiF) produced in single crystals and doped with proper activators is a highly sensitive phosphor used in several applications such as integrated optics, colour centre laser and radiation dosimetry. In this work, we have developed a new synthetic chemical co-precipitation route for the synthesis of well-crystallized micro- and nanocrystalline cubes of pure and silver (Ag)-doped LiF. The as-synthesized samples were characterized by x-ray diffraction (XRD), scanning electron microscopy, absorption spectrum, photoluminescence (PL) and Raman spectroscopy. Size of the produced cubes could be controlled in the range 10 µm-50 nm by varying the solvent:co-solvent ratio. Micro-sized cubes could be grown in the presence of water as a solvent, while ethanol, which acts as a co-solvent, is found to be effective in reducing the size to the nanoscale. XRD results show complete crystalline structures in a griceite phase. The PL result of pure nanocubes exhibits a broad band in the range 370-550 nm, while that doped with Ag shows a prominent band at 420 nm. Raman spectra of the pure and Ag-doped LiF samples display several bands located in the range 80-236 cm -1 . These results show that pure nanocubes of LiF have active colour centres without irradiation, which could be enhanced/modified by Ag dopants. This implies that these nanocubes might be useful in the development of optical devices.

In-situ TEM observation of the response of ultrafine- and nanocrystalline-grained tungsten to extreme irradiation environments.

Science.gov (United States)

El-Atwani, O; Hinks, J A; Greaves, G; Gonderman, S; Qiu, T; Efe, M; Allain, J P

2014-05-06

The accumulation of defects, and in particular He bubbles, can have significant implications for the performance of materials exposed to the plasma in magnetic-confinement nuclear fusion reactors. Some of the most promising candidates for deployment into such environments are nanocrystalline materials as the engineering of grain boundary density offers the possibility of tailoring their radiation resistance properties. In order to investigate the microstructural evolution of ultrafine- and nanocrystalline-grained tungsten under conditions similar to those in a reactor, a transmission electron microscopy study with in situ 2 keV He(+) ion irradiation at 950 °C has been completed. A dynamic and complex evolution in the microstructure was observed including the formation of defect clusters, dislocations and bubbles. Nanocrystalline grains with dimensions less than around 60 nm demonstrated lower bubble density and greater bubble size than larger nanocrystalline (60-100 nm) and ultrafine (100-500 nm) grains. In grains over 100 nm, uniform distributions of bubbles and defects were formed. At higher fluences, large faceted bubbles were observed on the grain boundaries, especially on those of nanocrystalline grains, indicating the important role grain boundaries can play in trapping He and thus in giving rise to the enhanced radiation tolerance of nanocrystalline materials.

Characterization of nanocrystalline silicon germanium film and ...

African Journals Online (AJOL)

The nanocrystalline silicon-germanium films (Si/Ge) and Si/Ge nanotubes have low band gaps and high carrier mobility, thus offering appealing potential for absorbing gas molecules. Interaction between hydrogen molecules and bare as well as functionalized Si/Ge nanofilm and nanotube was investigated using Monte ...

Luminescence of nanocrystalline ZnSe:Mn2+

NARCIS (Netherlands)

Suyver, J.F.; Wuister, S.F.; Kelly, J.J.; Meijerink, A.

2000-01-01

The luminescence properties of nanocrystalline ZnSe:Mn^(2+) prepared via an inorganic chemical synthesis are described. Photoluminescence spectra show distinct ZnSe and Mn^(2+) related emissions, both of which are excited via the ZnSe host lattice. The Mn^(2+) emission wavelength and the

Large silver-cadmium technology program

Science.gov (United States)

Charlip, S.; Lerner, S.

1971-01-01

The effects of varying cell design on operation factors on the electrochemical performance of sealed, silver-cadmium cells were determined. A factorial experiment was conducted for all test cells constructed with organic separators. Three operating factors were evaluated: temperature, depth of discharge, and charge rate. The six construction factors considered were separator, absorber, electrolyte quantity, cadmium electrode type, cadmium-to-silver ratio, and auxiliary electrode. Test cells of 4 ampere-hour capacity were fabricated and cycled. The best performing cells, on a 94 minute orbit, at 40% depth of discharge, were those containing silver-treated fibrous sausage casings as the separator, and Teflon-ated, pressed cadmium electrodes. Cycling data of cells with inorganic separators (Astroset) are given. Best performance was shown by cells with nonwoven nylon absorbers. Rigid inorganic separators provided the best barrier to silver migration.

Immunochromatographic assay of cadmium levels in oysters.

Science.gov (United States)

Nishi, Kosuke; Kim, In-Hae; Itai, Takaaki; Sugahara, Takuya; Takeyama, Haruko; Ohkawa, Hideo

2012-08-15

Oysters are one of foodstuffs containing a relatively high amount of cadmium. Here we report on establishment of an immunochromatographic assay (ICA) method of cadmium levels in oysters. Cadmium was extracted with 0.l mol L(-1) HCl from oysters and cleaned up from other metals by the use of an anion-exchange column. The behavior of five metals Mn, Fe, Cu, Zn, and Cd was monitored at each step of extraction and clean-up procedure for the ICA method in an inductively coupled plasma-mass spectrometry (ICP-MS) analysis. The results revealed that a simple extraction method with the HCl solution was efficient enough to extract almost all of cadmium from oysters. Clean-up with an anion-exchange column presented almost no loss of cadmium adsorbed on the column and an efficient removal of metals other than cadmium. When a spiked recovery test was performed in the ICA method, the recovery ranged from 98% to 112% with relative standard deviations between 5.9% and 9.2%. The measured values of cadmium in various oyster samples in the ICA method were favorably correlated with those in ICP-MS analysis (r(2)=0.97). Overall results indicate that the ICA method established in the present study is an adequate and reliable detection method for cadmium levels in oysters. Copyright © 2012 Elsevier B.V. All rights reserved.

Nanocrystalline diamond coatings for machining

Energy Technology Data Exchange (ETDEWEB)

Frank, M.; Breidt, D.; Cremer, R. [CemeCon AG, Wuerselen (Germany)

2007-07-01

This history of CVD diamond synthesis goes back to the fifties of the last century. However, the scientific and economical potential was only gradually recognized. In the eighties, intensive worldwide research on CVD diamond synthesis and applications was launched. Industrial products, especially diamond-coated cutting tools, were introduced to the market in the middle of the nineties. This article shows the latest developments in this area, which comprises nanocrystalline diamond coating structures. (orig.)

Cadmium action in synapses in the brain

Energy Technology Data Exchange (ETDEWEB)

Minami, Akira; Takeda, Atsushi; Nishibaba, Daisuke; Tekefuta, Sachiyo; Oku, Naoto [Department of Radiobiochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka (Japan)

2001-05-01

Chronic exposure to cadmium causes central nervous system disorders, e.g., olfactory dysfunction. To clarify cadmium toxicity in synaptic neurotransmission in the brain, the movement and action of cadmium in the synapses was examined using in vivo microdialysis. One and 24 h after injection of {sup 109}CdCl{sub 2} into the amygdala of rats, {sup 109}Cd release into the extracellular space was facilitated by stimulation with high K{sup +}, suggesting that cadmium taken up in amygdalar neurons is released into the synaptic clefts in a calcium- and impulse-dependent manner. To examine the action of cadmium in the synapses, the amygdala was perfused with artificial cerebrospinal fluid containing 10-30 {mu}M CdCl{sub 2}. The release of excitatory neurotransmitters, i.e., glutamate and aspartate, into the extracellular space was decreased during perfusion with cadmium, while the release of inhibitory neurotransmitters, i.e., glycine and {gamma}-amino butyric acid (GABA), into the extracellular space was increased during the period. These results suggest that cadmium released from the amygdalar neuron terminals affects the degree and balance of excitation-inhibition in synaptic neurotransmission. (author)

Critical review of animal carcinogenesis by cadmium and its inorganic compounds

International Nuclear Information System (INIS)

Maximilien, R.; Dero, B.

1990-01-01

Animal carcinogenic biassays relative to 6 inorganic cadmium substances (cadmium metal, cadmium oxide, cadmium sulfide, cadmium sulfate, cadmium chloride and cadmium acetate) are reviewed (speciation). Critical evaluation of literature data on carcinogenicity has been performed by making reference to E.C. guidelines of good laboratory practice. There are few data on routes relevant for human risk assessment: experiments on inhalation demonstrate lung carcinogenicity of cadmium oxide, cadmium sulfide, cadmium sulfate and cadmium chloride in rats but not in mice nor in hamsters; no carcinogenic effects of cadmium compounds are observed following oral administration. For routes of less or no relevance for human risk assessment, some results are clearly positive: subcutaneous injection induces cancers in situ (various cadmium compounds), testicular tumours (cadmium sulfate and cadmium chloride) and prostatic tumours (cadmium chloride) but such effects are not observed using relevant malignancies in rats. With respect to other no relevant routes (intraperitoneal, intrarenal...) tumours are incidentally produced in situ, but not in remote organs. Numerous studies fail to demonstrate cadmium carcinogenicity, but methodologically acceptable negative ones are very limited in number. Accordingly strain dependent effects and dose effect relationship could not be thoroughly assessed

A study of size dependent structure, morphology and luminescence behavior of CdS films on Si substrate

International Nuclear Information System (INIS)

Kaushik, Diksha; Singh, Ragini Raj; Sharma, Madhulika; Gupta, D.K.; Lalla, N.P.; Pandey, R.K.

2007-01-01

Size tunable cadmium sulfide (CdS) films deposited by a dip coating technique on silicon (100) and indium tin oxide/glass substrates have been characterized using X-ray diffraction, X-ray reflectivity, transmission electron microscopy, atomic force microscopy and photoluminescence spectroscopy. The structural characterization indicated growth of an oriented phase of cadmium sulfide. Transmission electron microscopy used to calculate the particle size indicated narrow size dispersion. The tendency of nanocrystalline CdS films to form ordered clusters of CdS quantum dots on silicon (100) substrate has been revealed by morphological studies using atomic force microscopy. The photoluminescence emission spectroscopy of the cadmium sulfide films has also been investigated. It is shown that the nanocrystalline CdS exhibit intense photoluminescence as compared to the large grained polycrystalline CdS films. The effect of quantum confinement also manifested as a blue shift of photoluminescence emission. It is shown that the observed photoluminescence behavior of CdS is substantially enhanced when the nanocrystallites are assembled on silicon (100) substrate

Growth of cadmium oxide whiskers on cadmium sulphide single crystals with copper as growth activator

Energy Technology Data Exchange (ETDEWEB)

Koparanova, N.; Simov, S. (Bylgarska Akademiya na Naukite, Sofia. Inst. po Fizika na Tvyrdoto Tyalo); Genchev, D. (Bylgarska Akademiya na Naukite, Sofia. Inst. za Yadrena Izsledvaniya i Yadrena Energetika); Metchenov, G. (Research Inst. of Criminalistics and Criminology, Sofia (Bulgaria))

1985-02-01

Some results on the growth and morphology of cadmium oxide whiskers, obtained on cadmium sulphide single crystals with copper as a growth activator, are presented in this work. Cadmium oxide whiskers have been obtained on brace 112-bar0 brace faces of cadmium sulphide plates with a copper layer deposited in advance. The whiskers grew during the annealing of the plates in a weak stream of technically pure argon at temperatures 670 to 730 deg C for 15 min to 3.5 h. Details about the procedure have been given elsewhere. The composition and morphology of the whiskers have been studied by an X-ray microanalyser JEOL 35 DDS and a scanning electron microscope JEOL, JSM 35. The optical microscopic observations have shown that after annealing, a gray-black granular layer is formed on the cadmium sulphide single crystals and this layer can easily be separated from the crystal substrate. Under the granular layer the crystal is heavily damaged. The whiskers grow on the granular layer and they are coloured yellow-brown or red-brown. The maximum whisker length attains several hundreds of micrometres and in some cases up to 1 mm or more.

Growth of cadmium oxide whiskers on cadmium sulphide single crystals with copper as growth activator

International Nuclear Information System (INIS)

Koparanova, N.; Simov, S.

1985-01-01

Some results on the growth and morphology of cadmium oxide whiskers, obtained on cadmium sulphide single crystals with copper as a growth activator, are presented in this work. Cadmium oxide whiskers have been obtained on brace 112-bar0 brace faces of cadmium sulphide plates with a copper layer deposited in advance. The whiskers grew during the annealing of the plates in a weak stream of technically pure argon at temperatures 670 to 730 deg C for 15 min to 3.5 h. Details about the procedure have been given elsewhere. The composition and morphology of the whiskers have been studied by an X-ray microanalyser JEOL 35 DDS and a scanning electron microscope JEOL, JSM 35. The optical microscopic observations have shown that after annealing, a gray-black granular layer is formed on the cadmium sulphide single crystals and this layer can easily be separated from the crystal substrate. Under the granular layer the crystal is heavily damaged. The whiskers grow on the granular layer and they are coloured yellow-brown or red-brown. The maximum whisker length attains several hundreds of micrometres and in some cases up to 1 mm or more. (author)

Synthesis and in-depth analysis of highly ordered yttrium doped hydroxyapatite nanorods prepared by hydrothermal method and its mechanical analysis

International Nuclear Information System (INIS)

Nathanael, A. Joseph; Mangalaraj, D.; Hong, S.I.; Masuda, Y.

2011-01-01

In this study, undoped and yttrium (Y) doped nanocrystalline hydroxyapatite crystals were synthesized by the hydrothermal method at 180 °C for 24 h. Highly ordered and oriented hydroxyapatite (HAp) nanorods were prepared by yttrium doping and their nanostructure and physical properties were compared with those of undoped HAp rods. FESEM images showed that the doping with Y ions reduced the diameter (from 25 nm to 15 nm) and increased the length (from 95 nm to 115 nm) of the synthesized rods. The aspect ratio of the undoped and Y-doped nanorods were calculated to be 4.303 (SD = 0.0959) and 7.61 (SD = 0.0355), respectively. Specific surface area (SSA) analysis showed that SSA also increased from 66.74 m 2 /g to 68.57 m 2 /g with the addition of yttrium. Y-doped HAp nanorod reinforced HMWPE composites displayed the better mechanical performance than those reinforced with pure HAp nanorods. The possible strengthening of nanorods and the increase of SSA due to the reduction in the size of nanorods in the presence of yttrium may have contributed to the strengthening of Y-doped HAp/HMWPE composites. - Graphical Abstract: Highly ordered and oriented yttrium doped hydroxyapatite (HAp) nanorods were prepared by hydrothermal method. For undoped HAp the average length of the nanorod is 95 nm with mean diameter of 24 nm and for a Y doped nanorod the average length is ∼ 115 nm and the mean diameter is 15 nm. Mechanical analysis was carried out by polymer/nanoparticle composite method. Highlights: ► Yttrium doped hydroxyapatite nanorods were prepared by hydrothermal method. ► The nanorods have highly uniform size distribution. ► Yttrium substitution and nanostructure formation was confirmed by careful analysis. ► Mechanical strength was analyzed by polymer nanoparticle reinforcement method.

Effect of iron content on permeability and power loss characteristics of

Indian Academy of Sciences (India)

Magnetic properties like saturation magnetization, coercivity, retentivity have been measured by vibrating sample magnetometer (VSM). The permeability of cadmium doped lithium ferrites exhibited higher values than zinc doped lithium ferrites. The power loss of cadmium doped lithium ferrites is lesser as compared to zinc ...

Preparation, characterization and luminescence of nanocrystalline Y2O3:Ho

International Nuclear Information System (INIS)

Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko; Mestrovic, Ernest

2007-01-01

Nanocrystalline Y 2 O 3 :Ho was synthesized by solution combustion method with ethylene glycol as fuel. Material was characterized using powder X-ray diffraction and transmission electron microscopy (TEM). X-ray diffraction and TEM showed that the material is nanostructured. Luminescence properties were studied using Raman spectrometers with excitation in near infrared (NIR) and visible regions. The visible and NIR luminescence spectra of nanocrystalline Y 2 O 3 :Ho show some important differences from those of bulk material. The convenience of using Raman instruments for studying luminescence of lanthanide ions is demonstrated

Chemical vapor deposition of nanocrystalline diamond films

International Nuclear Information System (INIS)

Vyrovets, I.I.; Gritsyna, V.I.; Dudnik, S.F.; Opalev, O.A.; Reshetnyak, O.M.; Strel'nitskij, V.E.

2008-01-01

The brief review of the literature is devoted to synthesis of nanocrystalline diamond films. It is shown that the CVD method is an effective way for deposition of such nanostructures. The basic technological methods that allow limit the size of growing diamond crystallites in the film are studied.

Synthesis and characterization of nanocrystalline zinc ferrite

DEFF Research Database (Denmark)

Jiang, J.S.; Yang, X.L.; Gao, L.

1999-01-01

Nanocrystalline zinc ferrite powders with a partially inverted spinel structure were synthesized by high-energy ball milling in a closed container at ambient temperature from a mixture of alpha-Fe2O3 and ZnO crystalline powders in equimolar ratio. From low-temperature and in-field Mossbauer...

Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

International Nuclear Information System (INIS)

Mouro, J.; Gualdino, A.; Chu, V.; Conde, J. P.

2013-01-01

Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n + -type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three different types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force

Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

Energy Technology Data Exchange (ETDEWEB)

Mouro, J.; Gualdino, A.; Chu, V. [Instituto de Engenharia de Sistemas e Computadores – Microsistemas e Nanotecnologias (INESC-MN) and IN – Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Conde, J. P. [Instituto de Engenharia de Sistemas e Computadores – Microsistemas e Nanotecnologias (INESC-MN) and IN – Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Department of Bioengineering, Instituto Superior Técnico (IST), 1049-001 Lisbon (Portugal)

2013-11-14

Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n{sup +}-type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three different types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force.

Atomistic simulation study of deformation twinning of nanocrystalline body-centered cubic Mo

Energy Technology Data Exchange (ETDEWEB)

Tian, Xiaofeng [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Li, Dan, E-mail: txf8378@163.com [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Yu, You [College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu (China); You, Zhen Jiang [Australian School of Petroleum, University of Adelaide, SA 5005 (Australia); Li, Tongye [The National Key Laboratory of Nuclear Fuel and Materials, Nuclear Power Institute of China, Chengdu (China); Ge, Liangquan [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China)

2017-04-06

Deformation twinning of nanocrystalline body-centered cubic Mo was studied using molecular dynamics simulations, and the effects of grain sizes and temperatures on the deformation were evaluated. With small grain size, grain rotation accompanying grain growth was found to play important role in nanocrystalline Mo during tensile deformation. Additionally, grain rotation and the deformation controlled by GB-mediated processes induce to the difficulty of creating crack. Twin was formed by successive emission of twinning partials from grain boundaries in small grain size systems. However, the twin mechanisms of GB splitting and overlapping of two extended dislocations were also found in larger size grain. Twin induced crack tips were observed in our simulation, and this confirmed the results of previous molecular dynamics simulations. At higher temperatures, GB activities can be thermally activated, resulting in suppression of twinning tendency and improvement of ductility of nanocrystalline Mo.

Cadmium accumulation and growth responses of a poplar (Populus deltoids x Populus nigra) in cadmium contaminated purple soil and alluvial soil

Energy Technology Data Exchange (ETDEWEB)

Wu Fuzhong [Faculty of Forestry, Sichuan Agricultural University, 625014, Ya' an (China); Yang Wanqin, E-mail: scyangwq@163.com [Faculty of Forestry, Sichuan Agricultural University, 625014, Ya' an (China); Zhang Jian; Zhou Liqiang [Faculty of Forestry, Sichuan Agricultural University, 625014, Ya' an (China)

2010-05-15

To characterize the phytoextraction efficiency of a hybrid poplar (Populus deltoids x Populus nigra) in cadmium contaminated purple soil and alluvial soil, a pot experiment in field was carried out in Sichuan basin, western China. After one growing period, the poplar accumulated the highest of 541.98 {+-} 19.22 and 576.75 {+-} 40.55 {mu}g cadmium per plant with 110.77 {+-} 12.68 and 202.54 {+-} 19.12 g dry mass in these contaminated purple soil and alluvial soil, respectively. Higher phytoextraction efficiency with higher cadmium concentration in tissues was observed in poplar growing in purple soil than that in alluvial soil at relative lower soil cadmium concentration. The poplar growing in alluvial soil had relative higher tolerance ability with lower reduction rates of morphological and growth characters than that in purple soil, suggesting that the poplar growing in alluvial soil might display the higher phytoextraction ability when cadmium contamination level increased. Even so, the poplars exhibited obvious cadmium transport from root to shoot in both soils regardless of cadmium contamination levels. It implies that this examined poplar can extract more cadmium than some hyperaccumulators. The results indicated that metal phytoextraction using the poplar can be applied to clean up soils moderately contaminated by cadmium in these purple soil and alluvial soil.

Grain boundaries of nanocrystalline materials - their widths, compositions, and internal structures

International Nuclear Information System (INIS)

Fultz, B.; Frase, H.N.

2000-01-01

Nanocrystalline materials contain many atoms at and near grain boundaries. Sufficient numbers of Moessbauer probe atoms can be situated in grain boundary environments to make a clear contribution to the measured Moessbauer spectrum. Three types of measurements on nanocrystalline materials are reported here, all using Moessbauer spectrometry in conjunction with X-ray diffractometry, transmission electron microscopy, or small angle neutron scattering. By measuring the fraction of atoms contributing to the grain boundary component in a Moessbauer spectrum, and by knowing the grain size of the material, it is possible to deduce the average width of grain boundaries in metallic alloys. It is found that these widths are approximately 0.5 nm for fcc alloys and slightly larger than 1.0 nm for bcc alloys.Chemical segregation to grain boundaries can be measured by Moessbauer spectrometry, especially in conjunction with small angle neutron scattering. Such measurements on Fe-Cu and Fe 3 Si-Nb were used to study how nanocrystalline materials could be stabilized against grain growth by the segregation of Cu and Nb to grain boundaries. The segregation of Cu to grain boundaries did not stabilize the Fe-Cu alloys against grain growth, since the grain boundaries were found to widen and accept more Cu atoms during annealing. The Nb additions to Fe 3 Si did suppress grain growth, perhaps because of the low mobility of Nb atoms, but also perhaps because Nb atoms altered the chemical ordering in the alloy.The internal structure of grain boundaries in nanocrystalline materials prepared by high-energy ball milling is found to be unstable against internal relaxations at low temperatures. The Moessbauer spectra of the nanocrystalline samples showed changes in the hyperfine fields attributable to movements of grain boundary atoms. In conjunction with SANS measurements, the changes in grain boundary structure induced by cryogenic exposure and annealing at low temperature were found to be