Local CC2 response method for triplet states based on Laplace transform: excitation energies and first-order properties.

Science.gov (United States)

Freundorfer, Katrin; Kats, Daniel; Korona, Tatiana; Schütz, Martin

2010-12-28

A new multistate local CC2 response method for calculating excitation energies and first-order properties of excited triplet states in extended molecular systems is presented. The Laplace transform technique is employed to partition the left/right local CC2 eigenvalue problems as well as the linear equations determining the Lagrange multipliers needed for the properties. The doubles part in the equations can then be inverted on-the-fly and only effective equations for the singles part must be solved iteratively. The local approximation presented here is adaptive and state-specific. The density-fitting method is utilized to approximate the electron-repulsion integrals. The accuracy of the new method is tested by comparison to canonical reference values for a set of 12 test molecules and 62 excited triplet states. As an illustrative application example, the lowest four triplet states of 3-(5-(5-(4-(bis(4-(hexyloxy)phenyl)amino)phenyl)thiophene-2-yl)thiophene-2-yl)-2-cyanoacrylic acid, an organic sensitizer for solar-cell applications, are computed in the present work. No triplet charge-transfer states are detected among these states. This situation contrasts with the singlet states of this molecule, where the lowest singlet state has been recently found to correspond to an excited state with a pronounced charge-transfer character having a large transition strength.

Optical properties of titanium-di-oxide (TiO2) prepared by hydrothermal method

Science.gov (United States)

Rahman, Kazi Hasibur; Biswas, Sayari; Kar, Asit Kumar

2018-05-01

Research on titanate and its derived TiO2 nanostructures with large specific surface area have received great attention due to their enhanced efficiency in photocatalysis, DSSC etc. Here, in this communication TiO2 powder has been prepared by hydrothermal method at 180 °C. In this work we have shown the changes in optical properties of the powder with two different sintering temperatures ‒ 500 °C and 800 °C. The as prepared powder was also studied. FESEM images show spherical particles for the as prepared samples which look more like agglomeration after sintering. Band gaps of the prepared samples were calculated from UV-Vis spectroscopy which lies in the range 2.85 eV ‒ 3.13 eV. The photoluminescence (PL) spectra of the prepared samples were recorded at room temperature in the range of 300‒700 nm. It shows two distinct peaks at 412 nm and 425 nm.

Analysis of noise properties of a class of exact methods of inverting the 2-D exponential radon transform

International Nuclear Information System (INIS)

Pan, X.; Metz, C.E.

1995-01-01

A general approach that the authors proposed elsewhere reveals the intrinsic relationship among methods for inversion of the 2-D exponential Radon transform described by Bellini et al., by Tretiak and Metz, by Hawkins et al., and by Inouye et al. Moreover, the approach provides an infinite class of linear methods for inverting the 2-D exponential Radon transform. In the work reported here, they systematically investigated the noise characteristics of the methods in this class, obtaining analytical forms for the autocovariance and the variance of the images reconstructed by use of various methods. The noise properties of a new quasi-optimal method were then compared theoretically to those of other methods of the class. The analysis demonstrates that the quasi-optimal method achieves smaller global variance in the reconstructed images than do the other methods of the class. Extensive numerical simulation studies confirm this prediction

Effects of TiO{sub 2} buffer layer on the photoelectrochemical properties of TiO{sub 2} Nano rods grown by modified chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Lee, Tae-hyun; Ha, Jin-wook; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

2015-08-15

In this study, we grew TiO{sub 2} nano rods on TiO{sub 2}-film buffered FTO substrate using modified chemical bath deposition (M-CBD). The TiO{sub 2} buffer layer was grown by spin coating method with different RPM (revolutions per minute) values and deposition cycles. We investigated the effects of the RPM values and the deposition cycles on the morphological, structural and photoelectrochemical properties of TiO{sub 2} nano rods. In this work, we have also found that the morphological and structural properties of TiO{sub 2} nano rods affected the photoelectrochemical properties of TiO{sub 2} nano rods. And the maximum photocurrent density of 0.34 mA/cm{sup 2} at 0.6V (vs.SCE) was obtained from the buffer layer deposition process condition of 4,000 RPM and two-times buffer layer depositions.

Structural and optical properties of {beta}-FeSi{sub 2}/Si(100) prepared by laser ablation method

Energy Technology Data Exchange (ETDEWEB)

Kakemoto, H; Makita, Y; Obara, A; Tsai, Y; Sakuragi, S; Ando, S; Tsukamoto, T

1997-07-01

{beta}-FeSi{sub 2} is a promising material for the application of various electronic, optoelectronic and energy devices. The authors present here the semiconducting properties of {beta}-FeSi{sub 2} films on Si(100) substrate prepared by laser ablation method. Samples were grown using poly-crystalline bulk {beta}-FeSi{sub 2} prepared by horizontal gradient freeze method. For the monitoring of growth, in-situ observation of ablation plume was made through fluorescence spectroscopy. Reflection of high-energy electron beam diffraction (RHEED) was also made in-situ to see the surface morphology. Characterization of the films by X-ray diffraction presented purely {beta}(220) orientation. Raman scattering measurements at room temperature also indicated that the grown films are semiconducting {beta}-FeSi{sub 2}. Optical absorption spectra at room temperature showed absorption coefficient higher than 10{sup 5} cm{sup {minus}1} above the band-gap ({approximately}1.2 eV). It was revealed that high quality semiconducting {beta}-FeSi{sub 2} films can be fabricated by laser ablation method without post-annealing.

Thermal and Mechanical Properties of UO2 and PuO2

International Nuclear Information System (INIS)

Kato, M.; Matsumoto, T.

2015-01-01

It is important to evaluate basic properties of UO 2 and PuO 2 as fundamental aspects of MA-bearing MOX fuel development. In this work, mechanical properties of UO 2 and PuO 2 were investigated by an ultrasound pulse-echo method. Longitudinal and transversal wave velocities were measured in UO 2 and PuO 2 pellets, and Young's modulus and shear modulus were evaluated, which were 219 MPa and 89 MPa for PuO 2 , and 249 MPa and 95 MPa for UO 2 , respectively. Poisson's ratio was 0.32 in both materials. The relationship between mechanical and thermal properties was described by using thermal expansion data which had been reported previously, and the heat capacity and thermal conductivity were analysed. (authors)

Structure and properties of nanosize NiFe2O4 prepared by template and precipitation methods

Czech Academy of Sciences Publication Activity Database

Ćosović, A.; Ćosović, B.; Žák, Tomáš; David, Bohumil; Talijan, N.

2013-01-01

Roč. 49, č. 3 (2013), s. 271-277 ISSN 1450-5339 R&D Projects: GA ČR(CZ) GAP108/11/1350; GA MŠk(CZ) ED1.1.00/02.0068 Institutional research plan: CEZ:AV0Z2041904 Institutional support: RVO:68081723 Keywords : nanosized NiFe2O4 * template method * precipitation route * microstructure * phase composition * magnetic properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.135, year: 2013

Photoluminescence properties of Eu2+-activated Ca2Y2Si2O9 phosphor

NARCIS (Netherlands)

Zhang, Zhijun; Delsing, A.C.A.; Notten, P.H.L.; Zhao, Jingtai; Hintzen, H.T.J.M.

2012-01-01

Eu2+-activated Ca2Y2Si2O9 phosphors with different Eu2+ concentrations have been prepared by a solid-state reaction method at high temperature and their photoluminescence (PL) properties were investigated. Photoluminescence results show that Eu2+-doped Ca2Y2Si2O9 can be efficiently excited by

Preparation by Poly(Acrylic Acid) Sol-Gel Method and Thermoelectric Properties of γ-Na x CoO2 Bulk Materials

Science.gov (United States)

Li, Xiaoyu; Zhang, Li; Tang, Xinfeng

2017-11-01

γ-Na x CoO2 single-phase powders have been synthesized by a poly(acrylic acid) (PAA) sol-gel (SG) method, and γ-Na x CoO2 bulk ceramic fabricated using spark plasma sintering. The effects of the PAA concentration on the sample phase composition and morphology were investigated. The thermoelectric properties of the γ-Na x CoO2 bulk ceramic were also studied. The results show that the PAA concentration did not significantly affect the crystalline phase of the product. However, agglomeration of γ-Na x CoO2 crystals was suppressed by the steric effect of PAA. The Na x CoO2 bulk ceramic obtained using the PAA SG method had higher crystallographic anisotropy, better chemical homogeneity, and higher density than the sample obtained by solid-state reaction (SSR), leading to improved thermoelectric performance. The PAA SG sample had power factor (in-plane PF = σS 2) of 0.61 mW m-1 K-2 and dimensionless figure of merit ( ZT) along the in-plane direction of 0.19 at 900 K, higher than for the SSR sample (in-plane PF = 0.51 mW m-1 K-2, in-plane ZT = 0.17). These results demonstrate that a simple and feasible PAA SG method can be used for synthesis of Na x CoO2 ceramics with improved thermoelectric properties.

The gas-sensing properties of thick film sensors based on nano-ZnFe2O4 prepared by hydrothermal method

International Nuclear Information System (INIS)

Chu Xiangfeng; Jiang Dongli; Zheng Chenmou

2006-01-01

ZnFe 2 O 4 sensors were fabricated from nano-ZnFe 2 O 4 powders prepared by hydrothermal method and their gas-sensing properties were investigated. It was found that the phase composition of the product and the gas-sensing properties greatly depend on the reaction pH value and the reaction temperature. Nano-ZnFe 2 O 4 powders could be obtained at a pH of 8-10 and the sensor based on the nano-ZnFe 2 O 4 powder prepared at 220 deg. C exhibited the best performance, characterized by high sensitivity to low concentrations of C 2 H 5 OH at 180 deg. C, especially, the sensitivity to 100 ppm C 2 H 5 OH was as high as 76

A comparative study of magnetic properties of MnFe2O4 nanoparticles prepared by thermal decomposition and solvothermal methods

Directory of Open Access Journals (Sweden)

B Aslibeiki

2017-09-01

Full Text Available A comparative study of magnetic properties of MnFe2O4 ferrite nanoparticles prepared by two different methods has been reported. The first sample (S1 was synthesized by thermal decomposition of metal nitrates. And the second sample (S2 was prepared by solvothermal method using Tri-ethylene glycol (TEG. Magnetic hysteresis loops at 300 and 5 K; magnetization and AC susceptibility measurements versus temperature confirmed the effective role of TEG on the magnetic properties of nanoparticles. The results showed that, at 300 K the saturation magnetization (MS of S2 sample is 46% greater than that of S1 sample. At 5 K, the difference in MS of the samples raised to 60%. AC susceptibility measurements at different frequencies and also magnetization versus temperature under field cooling and zero field cooling processes revealed that, the TEG molecules influence the surface spins order of S2 sample. The sample S1 showed strongly interacting superspin glass state, while the sample S2 consists of weakly interacting superparamagnetic nanoparticles.

Electronic Structure and Optical Properties Of EuIn2P2

KAUST Repository

Singh, Nirpendra; Schwingenschlö gl, Udo; Rhee, J. Y.

2011-01-01

The electronic structures and, optical and magneto‐optical properties of a newly found Zintl compound EuIn2P2 have been investigated within the density‐functional theory using the highly precise full‐potential linear‐augmented‐plane‐wave method

41 CFR 105-8.150-2 - Methods.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Methods. 105-8.150-2... HANDICAP IN PROGRAMS OR ACTIVITIES CONDUCTED BY GENERAL SERVICES ADMINISTRATION § 105-8.150-2 Methods. (a... construction of new facilities, use of accessible rolling stock, or any other methods that result in making its...

Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

Directory of Open Access Journals (Sweden)

Nosipho Moloto

2012-01-01

Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The photoluminescence spectrum of TiO2 nanotubes shows good improvement from previously reported data.

Magnetic Properties of Ni-Zn Ferrite Prepared with the Layered Precursor Method

International Nuclear Information System (INIS)

Zhou Xin; Hou Zhi-Ling; Li Feng; Qi Xin

2010-01-01

We prepare NiZnFe 2 O 4 soft magnetic ferrites with different molar ratios with the layered precursor method and investigate their magnetic properties. In the layered precursor, metal ions are scattered on the layer plate in a certain way on account of the effect of lowest lattice energy and lattice orientation. After high temperature calcinations, spinel ferrites with uniform structural component and single magnetic domain can be obtained, and the magnetic property is improved greatly. NiZnFe 2 O 4 ferrites prepared have the best specific saturation magnetization of 79.15 emu·g −1 , higher than that of 68 emu·g −1 prepared by the chemical co-precipitation method and that of 59 emu·g −1 prepared by the emulsion-gel method. Meanwhile the coercivity of NiZnFe 2 O 4 ferrites prepared by layered precursor method is 14 kA·m −1 , lower than that of 50 emu·g −1 prepared by the co-precipitation method and that of 59 emu·g −1 prepared by the emulsion-gel method. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

The Variability and Evaluation Method of Recycled Concrete Aggregate Properties

Directory of Open Access Journals (Sweden)

Zhiqing Zhang

2017-01-01

Full Text Available With the same sources and regeneration techniques, given RA’s properties may display large variations. The same single property index of different sets maybe has a large difference of the whole property. How shall we accurately evaluate the whole property of RA? 8 groups of RAs from pavement and building were used to research the method of evaluating the holistic characteristics of RA. After testing and investigating, the parameters of aggregates were analyzed. The data of physical and mechanical properties show a distinct dispersion and instability; thus, it has been difficult to express the whole characteristics in any single property parameter. The Euclidean distance can express the similarity of samples. The closer the distance, the more similar the property. The standard variance of the whole property Euclidean distances for two types of RA is Sk=7.341 and Sk=2.208, respectively, which shows that the property of building RA has great fluctuation, while pavement RA is more stable. There are certain correlations among the apparent density, water absorption, and crushed value of RAs, and the Mahalanobis distance method can directly evaluate the whole property by using its parameters: mean, variance, and covariance, and it can provide a grade evaluation model for RAs.

Study of photoluminescence properties of CaAl{sub 2}O{sub 4}: Eu{sup 2+} prepared by combustion synthesis method

Energy Technology Data Exchange (ETDEWEB)

Hingwe, V. S., E-mail: vishwas.hingwe@yahoo.in; Omanwar, S. K. [Department of physics, SGB Amravati University Amravati-444602 (India); Bajaj, N. S. [Toshniwal Arts, Commerce and Science College Sengaon-431542 (India)

2016-05-06

Eu{sup 2+} doped alkaline earth metals such as strontium aluminate, calcium aluminate and barium aluminate prepared by using modified combustion synthesis method at 600°C with Urea as fuel. Crystal structure is determined by using XRD and the sample confirmation by using the FTIR. The effect of the host material on the photoluminescence (PL) and phosphorescence properties were studied by using the Hitachi F-7000 spectrofluorimeter equipped with a 450W Xenon lamp, in the range 200-650 nm. The emission spectra of Eu{sup 2+} range from 450 to 500 nm in the Blue to aqua region and the transition 4f{sup 7}-4f{sup 6} 5d{sup 1}. The observed emission in CaAl{sub 2}O{sub 4} is 440 nm.

Elastic properties of Na 2 O–ZnO–ZnF 2

Indian Academy of Sciences (India)

Elastic properties of Na2O–ZnO–ZnF2–B2O3 oxyfluoride glasses with different ZnF2 concentrations have been investigated using ultrasonic velocity measurements at room temperature, at a frequency of 10 MHz. Glasses prepared by melt quenching method were suitably polished for the ultrasonic velocity measurements ...

Preparation of cobalt-zinc ferrite (Co0.8Zn0.2Fe2O4) nanopowder via combustion method and investigation of its magnetic properties

International Nuclear Information System (INIS)

Yousefi, M.H.; Manouchehri, S.; Arab, A.; Mozaffari, M.; Amiri, Gh. R.; Amighian, J.

2010-01-01

Research highlights: → Cobalt-zinc ferrite was prepared by combustion method. → Properties of the sample were characterized by several techniques. → Curie temperature was determined to be 350 o C. -- Abstract: Cobalt-zinc ferrite (Co 0.8 Zn 0.2 Fe 2 O 4 ) was prepared by combustion method, using cobalt, zinc and iron nitrates. The crystallinity of the as-burnt powder was developed by annealing at 700 o C. Crystalline phase was investigated by XRD. Using Williamson-Hall method, the average crystallite sizes for nanoparticles were determined to be about 27 nm before and 37 nm after annealing, and residual stresses for annealed particles were omitted. The morphology of the annealed sample was investigated by TEM and the mean particle size was determined to be about 30 nm. The final stoichiometry of the sample after annealing showed good agreement with the initial stoichiometry using atomic absorption spectrometry. Magnetic properties of the annealed sample such as saturation magnetization, remanence magnetization, and coercivity measured at room temperature were 70 emu/g, 14 emu/g, and 270 Oe, respectively. The Curie temperature of the sample was determined to be 350 o C using AC-susceptibility technique.

Development of Titanium Dioxide (TiO2 ) Nanocoatings on Food Contact Surfaces and Method to Evaluate Their Durability and Photocatalytic Bactericidal Property.

Science.gov (United States)

Yemmireddy, Veerachandra K; Farrell, Glenn D; Hung, Yen-Con

2015-08-01

Titanium dioxide (TiO2 ) is a well-known photocatalyst for its excellent bactericidal property under UVA light. The purpose of this study was to develop physically stable TiO2 coatings on food contact surfaces using different binding agents and develop methods to evaluate their durability and microbicidal property. Several types of organic and inorganic binders such as polyvinyl alcohol, polyethylene glycol, polyurethane, polycrylic, sodium and potassium silicates, shellac resin, and other commercial binders were used at 1:1 to 1:16 nanoparticle to binder weight ratios to develop a formulation for TiO2 coating on stainless steel surfaces. Among the tested binders, polyurethane, polycrylic, and shellac resin were found to be physically more stable when used in TiO2 coating at 1:4 to 1:16 weight ratio. The physical stability of TiO2 coatings was determined using adhesion strength and scratch hardness tests by following standard ASTM procedures. Further, wear resistance of the coatings was evaluated based on a simulated cleaning procedure used in food processing environments. TiO2 coating with polyurethane at a 1:8 nanoparticle to binder weight ratio showed the highest scratch hardness (1.08 GPa) followed by coating with polycrylic (0.68 GPa) and shellac (0.14 GPa) binders. Three different techniques, namely direct spreading, glass cover-slip, and indented coupon were compared to determine the photocatalytic bactericidal property of TiO2 coatings against Escherichia coli 0157:H7 at 2 mW/cm(2) UVA light intensity. Under the tested conditions, the indented coupon technique was found to be the most appropriate method to determine the bactericidal property of TiO2 coatings and showed a reduction of 3.5 log CFU/cm(2) in 2 h. © 2015 Institute of Food Technologists®

Nanosilicon properties, synthesis, applications, methods of analysis and control

CERN Document Server

Ischenko, Anatoly A; Aslalnov, Leonid A

2015-01-01

Nanosilicon: Properties, Synthesis, Applications, Methods of Analysis and Control examines the latest developments on the physics and chemistry of nanosilicon. The book focuses on methods for producing nanosilicon, its electronic and optical properties, research methods to characterize its spectral and structural properties, and its possible applications. The first part of the book covers the basic properties of semiconductors, including causes of the size dependence of the properties, structural and electronic properties, and physical characteristics of the various forms of silicon. It presents theoretical and experimental research results as well as examples of porous silicon and quantum dots. The second part discusses the synthesis of nanosilicon, modification of the surface of nanoparticles, and properties of the resulting particles. The authors give special attention to the photoluminescence of silicon nanoparticles. The third part describes methods used for studying and controlling the structure and pro...

Comparison of Thermal Properties Measured by Different Methods

International Nuclear Information System (INIS)

Sundberg, Jan; Kukkonen, Ilmo; Haelldahl, Lars

2003-04-01

A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

Comparison of Thermal Properties Measured by Different Methods

Energy Technology Data Exchange (ETDEWEB)

Sundberg, Jan [Geo Innova AB, Linkoeping (Sweden); Kukkonen, Ilmo [Geological Survey of Finland, Helsinki (Finland); Haelldahl, Lars [Hot Disk AB, Uppsala (Sweden)

2003-04-01

A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

Synthesis of Ni(OH)2 Nanoflakes Through a Novel Ion Diffusion Method Controlled by Ion Exchange Membrane and Electrochemical Supercapacitive Properties

International Nuclear Information System (INIS)

Zhao, Jiangshan; Zhang, Qiang

2015-01-01

Highlights: • We synthesized β-Ni(OH) 2 nanoflakes through a novel ion diffusion method. • The possible formation mechanism of the Ni(OH) 2 nanoflakes was discussed. • The temperature influence on growth of Ni(OH) 2 nanocrystals and its subsequent effect on electrochemical supercapacitive properties were examined. • The β-Ni(OH) 2 nanoflakes prepared at 50 °C for 12 h exhibits the highest specific capacitance of 2102 F g −1 . - Abstract: A novel method, ion diffusion method controlled by ion exchange membrane was reported for the synthesis of Ni(OH) 2 nanomaterials in the absence of any template or organic surfactant. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), BET specific surface area and pore size distribution analyzer. It can be observed that β-Ni(OH) 2 nanoflake-like structure was obtained, and the sheet size, thickness and pore size of as-prepared samples can be controlled by altering reaction time and reaction temperature. The BET specific surface area of Ni(OH) 2 nanomaterials obtained by this method can be up to 280.5 m 2 /g at 30 °C. The electrochemical supercapacitive properties of Ni(OH) 2 nanostructures have been investigated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy techniques. All these Ni(OH) 2 samples exhibit good capacity for electrochemical supercapacitor in KOH electrolyte. The flake nanostructures synthesized at 50 °C for 12 h exhibit a highest specific capacitance of 2102 F g −1 at a current density of 20 mA cm −2 within the potential range of 0.5 V and the Ni(OH) 2 sample retains 85.1% of the initial capacitance even after 1000 continuous charge–discharge cycles. The results indicate that ion diffusion method controlled by ion exchange membrane is a useful method for synthesizing inorganic nanomaterials.

Effects of SiO2 nano-particles on tribological and mechanical properties of aluminum matrix composites by different dispersion methods

Science.gov (United States)

Azadi, Mahboobeh; Zolfaghari, Mehrdad; Rezanezhad, Saeid; Azadi, Mohammad

2018-05-01

This study has been presented with mechanical properties of aluminum matrix composites, reinforced by SiO2 nano-particles. The stir casting method was employed to produce various aluminum matrix composites. Different composites by varying the SiO2 nano-particle content (including 0.5 and 1 weight percents) and two dispersion methods (including ball-milling and pre-heating) were made. Then, the density, the hardness, the compression strength, the wear resistance and the microstructure of nano-composites have been studied in this research. Besides, the distribution of nano-particles in the aluminum matrix for all composites has been also evaluated by the field emission scanning electron microscopy (FESEM). Obtained results showed that the density, the elongation and the ultimate compressive strength of various nano-composites decreased by the presence of SiO2 nano-particles; however, the hardness, the wear resistance, the yield strength and the elastic modulus of composites increased by auditioning of nano-particles to the aluminum alloy. FESEM images indicated better wetting of the SiO2 reinforcement in the aluminum matrix, prepared by the pre-heating dispersion method, comparing to ball-milling. When SiO2 nano-particles were added to the aluminum alloy, the morphology of the Si phase and intermetallic phases changed, which enhanced mechanical properties. In addition, the wear mechanism plus the friction coefficient value were changed for various nano-composites with respect to the aluminum alloy.

Quasi-Experiments and Hedonic Property Value Methods

OpenAIRE

Christopher F. Parmeter; Jaren C. Pope

2012-01-01

There has recently been a dramatic increase in the number of papers that have combined quasi-experimental methods with hedonic property models. This is largely due to the concern that cross-sectional hedonic methods may be severely biased by omitted variables. While the empirical literature has developed extensively, there has not been a consistent treatment of the theory and methods of combining hedonic property models with quasi-experiments. The purpose of this chapter is to fill this void....

Structure and Photoluminescence Properties of β-Ga2O3 Nanofibres Synthesized via Electrospinning Method

Science.gov (United States)

Sun, Chao; Deng, Jinxiang; Kong, Le; Chen, Liang; Shen, Zhen; Cao, Yisen; Zhang, Hao; Wang, Xiaoran

2017-12-01

This paper reported the β-Ga2O3 nanofibres which fabricated by electrospinning, and then calcining in oxygen at 750, 850, 950 and 1050°C. The structure and properties of β-Ga2O3 nanofibers have been studied though kinds of methods such as XRD, Photoluminescence (PL) spectrum, Raman spectrum, Scanning electron microscope (SEM) and FT-IR. The diameters of these nanofibres are from 60 to 130nm and the lengths of these nanofibres are about couple millimetres. The spectrum of PL which excitation at 365nm gave us the information that the emission peak of these β-Ga2O3 nanofibres is about 470nm, it may be coursed by the various defects including the vacancies of gallium and oxygen and the gallium-oxygen vacancy pairs as well, and observed that with the increasing of the annealing temperature, the emission peaks have a small bule swifting, and the crystallinity become better at the same time.

Thermodynamic properties of 1-phenylnaphthalene and 2-phenylnaphthalene

International Nuclear Information System (INIS)

Chirico, Robert D.; Steele, William V.; Kazakov, Andrei F.

2014-01-01

Highlights: • Heat capacities, vapor pressures, enthalpies of combustion, and densities were measured for 1-phenylnaphthalene (1-PhN). • Heat capacities and vapor pressures were measured for 2-phenylnaphthalene (2-PhN). • Independent ideal-gas entropies derived with the calorimetric results and statistical methods are in accord for 1-PhN. • 2-PhN showed glassy-crystal behavior in the solid state, and an entropy deficit is demonstrated. - Abstract: Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for 1-phenylnaphthalene (Chemical Abstracts registry number [605-02-7]) and 2-phenylnaphthalene (Chemical Abstracts registry number [612-94-2]) are reported. Experimental methods for 1-phenylnaphthalene were adiabatic heat-capacity calorimetry, differential scanning calorimetry, inclined-piston manometry, comparative ebulliometry, vibrating-tube densitometry, and combustion calorimetry. For 2-phenylnaphthalene, the experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry, and comparative ebulliometry. Critical properties were estimated for both compounds. Molar thermodynamic functions (enthalpies, entropies, and Gibbs free energies) for the condensed and ideal-gas states were derived from the experimental studies at selected temperatures. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d, p) and B3LYP/cc-pVTZ levels of theory. Ideal-gas entropies derived with two the independent methods are shown to be in good accord for 1-phenylnaphthalene, but significant differences are apparent for 2-phenylnaphthalene. These differences are likely due to a disorder of unknown type in the crystals of 2-phenylnaphthalene at low temperatures, as evidenced by the presence of a glass-like transition in the measured heat capacities for the solid state. All experimental results are compared with property values

Impacts of oxidants in atomic layer deposition method on Al2O3/GaN interface properties

Science.gov (United States)

Taoka, Noriyuki; Kubo, Toshiharu; Yamada, Toshikazu; Egawa, Takashi; Shimizu, Mitsuaki

2018-01-01

The electrical interface properties of GaN metal-oxide-semiconductor (MOS) capacitors with an Al2O3 gate insulator formed by atomic layer deposition method using three kinds of oxidants were investigated by the capacitance-voltage technique, Terman method, and conductance method. We found that O3 and the alternate supply of H2O and O3 (AS-HO) are effective for reducing the interface trap density (D it) at the energy range of 0.15 to 0.30 eV taking from the conduction band minimum. On the other hand, we found that surface potential fluctuation (σs) induced by interface charges for the AS-HO oxidant is much larger than that for a Si MOS capacitor with a SiO2 layer formed by chemical vapor deposition despite the small D it values for the AS-HO oxidant compared with the Si MOS capacitor. This means that the total charged center density including the fixed charge density, charged slow trap density, and charged interface trap density for the GaN MOS capacitor is higher than that for the Si MOS capacitor. Therefore, σs has to be reduced to improve the performances and reliability of GaN devices with the Al2O3/GaN interfaces.

Spectral radiative property control method based on filling solution

International Nuclear Information System (INIS)

Jiao, Y.; Liu, L.H.; Hsu, P.-F.

2014-01-01

Controlling thermal radiation by tailoring spectral properties of microstructure is a promising method, can be applied in many industrial systems and have been widely researched recently. Among various property tailoring schemes, geometry design of microstructures is a commonly used method. However, the existing radiation property tailoring is limited by adjustability of processed microstructures. In other words, the spectral radiative properties of microscale structures are not possible to change after the gratings are fabricated. In this paper, we propose a method that adjusts the grating spectral properties by means of injecting filling solution, which could modify the thermal radiation in a fabricated microstructure. Therefore, this method overcomes the limitation mentioned above. Both mercury and water are adopted as the filling solution in this study. Aluminum and silver are selected as the grating materials to investigate the generality and limitation of this control method. The rigorous coupled-wave analysis is used to investigate the spectral radiative properties of these filling solution grating structures. A magnetic polaritons mechanism identification method is proposed based on LC circuit model principle. It is found that this control method could be used by different grating materials. Different filling solutions would enable the high absorption peak to move to longer or shorter wavelength band. The results show that the filling solution grating structures are promising for active control of spectral radiative properties. -- Highlights: • A filling solution grating structure is designed to adjust spectral radiative properties. • The mechanism of radiative property control is studied for engineering utilization. • Different grating materials are studied to find multi-functions for grating

Synthesis and photocatalytic properties of porous TiO2 films prepared by ODA/sol-gel method

International Nuclear Information System (INIS)

Zhang Wenjie; Bai Jiawei

2012-01-01

Porous TiO 2 films were deposited on SiO 2 pre-coated glass-slides by sol-gel method using octadecylamine (ODA) as template. The amount of ODA in the sol played an important role on the physicochemical properties and photocatalytic performance of the TiO 2 films. The films prepared at different conditions were all composed of anatase titanium dioxide crystals, and TiO 2 crystalline size got larger with increasing ODA amount. The maximum specific surface area of 41.5 m 2 /g was obtained for TiO 2 powders prepared from titanium sol containing 2.0 g ODA. Methyl orange degradation rate was enhanced along with increasing ODA amount and reached the maximal value at 2.0 g addition of ODA. After 40 min of UV-light irradiation, methyl orange degradation rate reached 30.5% on the porous film, which was about 10% higher than that on the smooth film. Porous TiO 2 film showed almost constant activity with slight decrease from 30.5% to 28.5% after 4 times of recycles.

CoFe2O4-SiO2 Composites: Preparation and Magnetodielectric Properties

Directory of Open Access Journals (Sweden)

T. Ramesh

2016-01-01

Full Text Available Cobalt ferrite (CoFe2O4 and silica (SiO2 nanopowders have been prepared by the microwave hydrothermal (M-H method using metal nitrates as precursors of CoFe2O4 and tetraethyl orthosilicate as a precursor of SiO2. The synthesized powders were characterized by XRD and FESEM. The (100-x (CoFe2O4 + xSiO2 (where x = 0%, 10%, 20%, and 30% composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD, Fourier transformation infrared (FTIR spectra, and scanning electron microscopy (SEM, respectively. The effect of SiO2 content on the magnetic and electrical properties of CoFe2O4/SiO2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.

Preparation of 2D MoSe2/PEDOT:PSS composite and its thermoelectric properties

Science.gov (United States)

Li, Xia; Liu, Congcong; Wang, Tongzhou; Wang, Wenfang; Wang, Xiaodong; Jiang, Qinglin; Jiang, Fengxing; Xu, Jingkun

2017-11-01

Nowadays, inorganic/polymer composites have attracted significant interest in thermoelectric field, since the composite materials usually achieve their respective advantages complementary to each other. In this work, molybdenum diselenide (MoSe2) was synthesized by a facile hydrothermal method. Solution processible two-dimensional (2D) MoSe2 nanosheets (NSs) were successfully obtained using dimethylsulfoxide (DMSO) solvent or lithium intercalation procedure. Combined with Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), MoSe2/PEDOT:PSS composite thin films were fabricated by direct vacuum-filtration method. Thermoelectric properties of composite thin films were investigated systematically and found that 2D MoSe2 NSs and PEDOT:PSS have the synergistic effect on improving thermoelectric properties. The maximum power factor was calculated to be 48.6 µW m-1 K-2 with 5 wt% 2D MoSe2 NSs embedding into PEDOT:PSS matrix, which is almost 69% higher than that of pure PEDOT:PSS. These results demonstrate that 2D inorganic/polymer composite method is one of promising strategies to get high-performance polymer-based thermoelectric composites.

Structural and electrical properties of TiO2/ZnO core–shell nanoparticles synthesized by hydrothermal method

International Nuclear Information System (INIS)

Vlazan, P.; Ursu, D.H.; Irina-Moisescu, C.; Miron, I.; Sfirloaga, P.; Rusu, E.

2015-01-01

TiO 2 /ZnO core–shell nanoparticles were successfully synthesized by hydrothermal method in two stages: first stage is the hydrothermal synthesis of ZnO nanoparticles and second stage the obtained ZnO nanoparticles are encapsulated in TiO 2 . The obtained ZnO, TiO 2 and TiO 2 /ZnO core–shell nanoparticles were investigated by means of X-ray diffraction, transmission electron microscopy, Brunauer, Emmett, Teller and resistance measurements. X-ray diffraction analysis revealed the presence of both, TiO 2 and ZnO phases in TiO 2 /ZnO core–shell nanoparticles. According to transmission electron microscopy images, ZnO nanoparticles have hexagonal shapes, TiO 2 nanoparticles have a spherical shape, and TiO 2 /ZnO core–shell nanoparticles present agglomerates and the shape of particles is not well defined. The activation energy of TiO 2 /ZnO core–shell nanoparticles was about 101 meV. - Graphical abstract: Display Omitted - Highlights: • TiO 2 /ZnO core–shell nanoparticles were synthesized by hydrothermal method. • TiO 2 /ZnO core–shell nanoparticles were investigated by means of XRD, TEM and BET. • Electrical properties of TiO 2 /ZnO core–shell nanoparticles were investigated. • The activation energy of TiO 2 /ZnO core–shell nanoparticles was about E a = 101 meV

Correlation between fuel structure and mechanical properties of UO2

International Nuclear Information System (INIS)

Blank, H.; Mandler, R.; Matzke, H.; Routbort, J.; Werner, P.

1982-10-01

The relation between the structure of a UO 2 fuel and its mechanical properties are discussed and illustrated for particular types of UO 2 by measurements of fracture surface energy, hardness, fracture stress and of compressive deformation at 1870 and 1970 0 K. This gives the background for treating the question whether it is possible to find a simple experimental method for correlating the mechanical properties of UO 2 before irradiation with those after various irradiation histories. Hardness measurements might be such a method if combined with a detailed structural analysis and sufficient knowledge about the irradiation history

Finite Element Method for Analysis of Material Properties

DEFF Research Database (Denmark)

Rauhe, Jens Christian

and the finite element method. The material microstructure of the heterogeneous material is non-destructively determined using X-ray microtomography. A software program has been generated which uses the X-ray tomographic data as an input for the mesh generation of the material microstructure. To obtain a proper...... which are used for the determination of the effective properties of the heterogeneous material. Generally, the properties determined using the finite element method coupled with X-ray microtomography are in good agreement with both experimentally determined properties and properties determined using......The use of cellular and composite materials have in recent years become more and more common in all kinds of structural components and accurate knowledge of the effective properties is therefore essential. In this wok the effective properties are determined using the real material microstructure...

Electronic and conformational properties of 2,3-benzodiazepine derivates

International Nuclear Information System (INIS)

Pelaggi, M.; Girlanda, R.; Chimirri, A.; Gitto, R.

1996-01-01

The molecular geometric and electronic structures of 2,3-benzodiazepine derivates have been studied by means of the MNDO-PM3 method. A number of electronic properties have been computed and examined in order to find indication of the role of the electronic characteristics of the different molecules and their pharmacological properties. Theoretical data indicate that both electronic and structural properties appear responsible for the varying degree of anticonvulsant activity exhibited by compounds 1-4

Electronic and conformational properties of 2,3-benzodiazepine derivates

Energy Technology Data Exchange (ETDEWEB)

Pelaggi, M.; Girlanda, R. [Messina Univ. (Italy). Dip. di Fisica della Materia e Fisica dell`Ambiente; Chimirri, A.; Gitto, R. [Messina Univ. (Italy). Dip. Farmaco-Chimico

1996-04-01

The molecular geometric and electronic structures of 2,3-benzodiazepine derivates have been studied by means of the MNDO-PM3 method. A number of electronic properties have been computed and examined in order to find indication of the role of the electronic characteristics of the different molecules and their pharmacological properties. Theoretical data indicate that both electronic and structural properties appear responsible for the varying degree of anticonvulsant activity exhibited by compounds 1-4.

Depolarization temperature and piezoelectric properties of Na1/2 ...

Indian Academy of Sciences (India)

1/2Bi1/2(Zn1/3Nb2/3)O3, was synthesized using the two-stage calcination method and depolarization temperatures and piezoelectric properties were also investigated. The XRD analysis showed that the ceramics system had a morphotropic ...

Crystallization Mechanism and Phase Transition Properties of W-doped VO2 Synthesized by Hydrothermal Method

Directory of Open Access Journals (Sweden)

LI Yao

2017-11-01

Full Text Available VO2 sol was firstly prepared using vanadyl sulfate as a vanadium source by precipitation-peptization method. Then tungsten(W doping vanadium dioxide(W-VO2 was prepared by hydrothermal crystallization of prepared sol with the presence of ammonium metatungstate. The morphologies, crystal structure of the as-prepared samples and phase transition properties were studied by X-ray diffraction(XRD, field emission scanning electron microscope(FESEMand differential scanning calorimetry(DSC analysis. The results indicate that rod-like W-VO2(B crystal with length of 1-2μm and radius of 100-200nm is firstly formed during hydrothermal treatment for 4-48h at 280℃, then the rod-like crystal dissolves gradually and sheet-like or snowflake-like crystal is formed with the phase transition from W-VO2(B to W-VO2(M and eventually, the W-VO2(M crystals can further grow up while the W-VO2(B gradually dissolves; the phase transition temperature of VO2 decreases with the increase in W doping content, and the phase transition temperature of W-VO2(M reduces to about 28℃ when the nominal dopant concentration is 6.0%(atom fraction.The "nucleation-growth-transformation-ripening" mechanism is proposed as the formation mechanism based on the hydrothermal crystallization and morphological evolution process of W-VO2(M.

Investigations on the synthesis, optical and electrical properties of TiO{sub 2} thin films by Chemical Bath Deposition (CBD) method

Energy Technology Data Exchange (ETDEWEB)

Govindasamy, Geetha [Bharathiar University, Coimbatore (India); Murugasen, Priya [Department of Physics, Saveetha Engineering College (India); Sagadevan, Suresh [Department of Physics, AMET University, Chennai (India)

2016-03-15

Titanium dioxide (TiO{sub 2} ) thin films were prepared by Chemical Bath Deposition (CBD) method. The X-ray diffraction (XRD) analysis was used to examine the structure and to determine the crystallite size of TiO{sub 2} thin film. The surface morphology of the film was studied using Scanning Electron Microscopy (SEM).The optical properties were studied using the UV-Visible and photoluminescence (PL) spectrum. Optical constants such as band gap, refractive index, extinction coefficient and electric susceptibility were determined. The FTIR spectrum revealed the strong presence of TiO{sub 2} . The dielectric properties of TiO{sub 2} thin films were studied for different frequencies and different temperatures. The AC electrical conductivity test revealed that the conduction depended both on the frequency and the temperature. Photoconductivity study was carried out in order to ascertain the positive photoconductivity of the TiO{sub 2} thin films. (author)

Estimation of oil reservoir thermal properties through temperature log data using inversion method

International Nuclear Information System (INIS)

Cheng, Wen-Long; Nian, Yong-Le; Li, Tong-Tong; Wang, Chang-Long

2013-01-01

Oil reservoir thermal properties not only play an important role in steam injection well heat transfer, but also are the basic parameters for evaluating the oil saturation in reservoir. In this study, for estimating reservoir thermal properties, a novel heat and mass transfer model of steam injection well was established at first, this model made full analysis on the wellbore-reservoir heat and mass transfer as well as the wellbore-formation, and the simulated results by the model were quite consistent with the log data. Then this study presented an effective inversion method for estimating the reservoir thermal properties through temperature log data. This method is based on the heat transfer model in steam injection wells, and can be used to predict the thermal properties as a stochastic approximation method. The inversion method was applied to estimate the reservoir thermal properties of two steam injection wells, it was found that the relative error of thermal conductivity for the two wells were 2.9% and 6.5%, and the relative error of volumetric specific heat capacity were 6.7% and 7.0%,which demonstrated the feasibility of the proposed method for estimating the reservoir thermal properties. - Highlights: • An effective inversion method for predicting the oil reservoir thermal properties was presented. • A novel model for steam injection well made full study on the wellbore-reservoir heat and mass transfer. • The wellbore temperature field and steam parameters can be simulated by the model efficiently. • Both reservoirs and formation thermal properties could be estimated simultaneously by the proposed method. • The estimated steam temperature was quite consistent with the field data

A Systematic Identification Method for Thermodynamic Property Modelling

DEFF Research Database (Denmark)

Ana Perederic, Olivia; Cunico, Larissa; Sarup, Bent

2017-01-01

In this work, a systematic identification method for thermodynamic property modelling is proposed. The aim of the method is to improve the quality of phase equilibria prediction by group contribution based property prediction models. The method is applied to lipid systems where the Original UNIFAC...... model is used. Using the proposed method for estimating the interaction parameters using only VLE data, a better phase equilibria prediction for both VLE and SLE was obtained. The results were validated and compared with the original model performance...

Different radiolabelling methods alter the pharmacokinetic and biodistribution properties of Plasminogen Activator Inhibitor Type 2 (PAI-2) forms

International Nuclear Information System (INIS)

Ranson, Marie; Berghofer, Paula; Vine, Kara L.; Greguric, Ivan; Shepherd, Rachael; Katsifis, Andrew

2012-01-01

Introduction: Tumour-associated urokinase plasminogen activator (uPA) is a critical marker of invasion and metastasis, and it is recognised as having strong prognostic relevance as well as being a therapeutic target. The specific uPA inhibitor plasminogen activator inhibitor type-2 (PAI-2, SerpinB2) specifically targets cell bound uPA and is internalised. Furthermore, preclinical studies have established the “proof-of-principle” of uPA-targeting by PAI-2-cytotoxin conjugates in human carcinoma models. However, these studies also suggest that PAI-2 is rapidly cleared via the renal system with low total dose reaching the tumour. In this study, a comparative single photon emission computed tomography (SPECT) and biodistribution (BD) analysis of different forms of PAI-2 labelled with the radioisotopes iodine-123 ( 123 I) and technetium-99m ( 99m Tc) was undertaken. Methods: The pharmacokinetic (PK) properties and BD of wild-type, ΔCD-loop and PEGylated ΔCD-loop PAI-2 labelled with the commonly used diagnostic SPECT radioisotopes 99m Tc or 123 I were compared in mouse models of human prostate carcinoma. Whole body SPECT imaging was also performed. Results: Both wild-type and the shorter but active ΔCD-loop form of PAI-2 123 I-labelled indirectly via conjugation to free amine groups (termed 123 I-Bn-PAI-2) exhibited low tumour uptake, rapid excretion and similar PK profiles. Preliminary studies with a short branched-chain PEGylated 123 I-Bn-PAI-2 ΔCD-loop indicated an increase in blood retention time and tumour uptake. All 123 I-Bn-labelled radiotracers were largely excreted through the kidneys. By comparison, both wild-type 123 I-PAI-2 (labelled directly via tyrosine residues) and 99m Tc-PAI-2 displayed different PK/BD patterns compared to 123 I-Bn-PAI-2, suggesting greater liver based catabolism and thus slower elimination. SPECT imaging mimicked the BD results of all radiotracers. Conclusion: The different labelling methods gave distinct PAI-2 BD and tumour

On the correlation between fuel structure and mechanical properties of UO2

International Nuclear Information System (INIS)

Blank, H.; Mandler, R.; Matzke, H.; Routbort, J.; Werner, P.

1983-01-01

The relation between the structure of a UO 2 fuel and its mechanical properties are discussed and illustrated for particular types of UO 2 by measurements of fracture surface energy, hardness, fracture stress and compressive deformation at 1870 and 1970 K. This gives the background for treating the question whether it is possible to find a simple experimental method for correlating the mechanical properties of UO 2 before irradiation with those after various irradiation histories. Hardness measurements might be such a method if combined with a detailed structural analysis and sufficient knowledge about the irradiation history. However, for a meaningful interpretation of the data the presently available 'classical' methods of fracture mechanics are inadequate and, furthermore, sufficient additional (not yet available) information on the relations between mechanical properties and structural details are required. (author)

Geometric, stable and electronic properties of Aun–2Y2 (n = 3–8) clusters

International Nuclear Information System (INIS)

Kai-Tian, Qi; Yong, Sheng; Hua-Ping, Mao; Hong-Yan, Wang

2010-01-01

Employing first-principles methods, based on the density function theory, and using the LANL2DZ basis sets, the ground-state geometric, the stable and the electronic properties of Au n–2 Y 2 clusters are investigated in this paper. Meanwhile, the differences in property among pure gold clusters, pure yttrium clusters, gold clusters doped with one yttrium atom, and gold clusters doped with two yttrium atoms are studied. We find that when gold clusters are doped by two yttrium atoms, the odd-even oscillatory behaviours of Au n–1 Y and Au n disappear. The properties of Au n–2 Y 2 clusters are close to those of pure yttrium clusters

Investigation of adsorption properties of alumina produced by vacuum spray method

International Nuclear Information System (INIS)

Khrustaleva, K; Voronova, G

2016-01-01

In this paper nanopowders obtained by vacuum spray method were studied. The phase composition of the obtained powders is γ - Al 2 O 3 . Obtained nanopowders have specific surface area about 200 m 2 /g. Adsorptive properties of these powders were studied by static adsorption from solutions. The anionic dye eosin was selected as adsorbate. It has been found that the powders obtained by vacuum spray method have significant capacity to adsorb eosin. (paper)

Optical and morphological properties of ZnO- and TiO2-derived nanostructures synthesized via a microwave-assisted hydrothermal method

CSIR Research Space (South Africa)

Moloto, N

2012-01-01

Full Text Available Corporation International Journal of Photoenergy Volume 2012, Article ID 189069, 6 pages doi:10.1155/2012/189069 Research Article Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave... International Journal of Photoenergy the sol-gel, hydrothermal process, and pulse laser deposition [22?24]. Although the sol-gel method is widely accepted for the preparation of both ZnO and TiO2 nanostructures, the calcinations process is essential and can...

Investigation on magnetic properties of orientated nanocomposite Pr2Fe14B/α-Fe permanent magnets by micromagnetic finite-element method

International Nuclear Information System (INIS)

He, Shu-li; Zhang, Hong-wei; Rong, Chuan-bing; Chen, Juan; Sun, Ji-rong; Shen, Bao-gen

2012-01-01

Demagnetization curves for nanocomposite Pr 2 Fe 14 B/α-Fe permanent magnets with different hard grain alignment are calculated by a micromagnetic finite-element method. The results show that both remanence and coercivity increase with improving hard grains alignment. The demagnetization curves show a single-phase demagnetization behavior for the samples with grain size d of 10 nm and two-phase behavior for the samples with d of 20 and 30 nm. H ex (reflecting the magnetic hardening of α-Fe) and H irr (expressing the irreversible reversal of hard phase) are both enhanced with improving the hard grain alignment. The magnetic reversal in orientated nanocomposite permanent magnets is mainly controlled by inhomogeneous pinning of the nucleated type. - Highlights: ► The magnetic properties of nanocomposite Pr 2 Fe 14 B/α-Fe permanent magnets with different hard grains alignment are investigated by micromagnetic finite-element method. ► The calculated results show that both remanence and coercivity increase with improving hard grains alignment. ► Highly ordered orientation of hard phase is the critical factor to improve the properties of nanocomposites.

Panel 2 - properties of diamond and diamond-like-carbon films

Energy Technology Data Exchange (ETDEWEB)

Blau, P.J.; Clausing, R.E. [Oak Ridge National Lab., TN (United States); Ajayi, O.O.; Liu, Y.Y.; Purohit, A. [Argonne National Lab., IL (United States); Bartelt, P.F. [Deere & Co., Moline, IL (United States); Baughman, R.H. [Allied Signal, Morristown, NJ (United States); Bhushan, B. [Ohio State Univ., Columbus (United States); Cooper, C.V. [United Technologies Research Center, East Hartford, CT (United States); Dugger, M.T. [Sandia National Laboratories, Albuquerque, NM (United States); Freedman, A. [Aerodyne Research, Inc., Billerica, MA (United States); Larsen-Basse, J. [National Science Foundation, Washington, DC (United States); McGuire, N.R. [Caterpillar, Peoria, IL (United States); Messier, R.F. [Pennsylvania State Univ., University Park (United States); Noble, G.L.; Ostrowki, M.H. [John Crane, Inc., Morton Grove, IL (United States); Sartwell, B.D. [Naval Research Lab., Washington, DC (United States); Wei, R. [Colorado State Univ., Fort Collins (United States)

1993-01-01

This panel attempted to identify and prioritize research and development needs in determining the physical, mechanical and chemical properties of diamond and diamond-like-carbon films (D/DLCF). Three specific goals were established. They were: (1) To identify problem areas which produce concern and require a better knowledge of D/DLCF properties. (2) To identify and prioritize key properties of D/DLCF to promote transportation applications. (3) To identify needs for improvement in properties-measurement methods. Each of these goals is addressed subsequently.

Dosimetric sensing and optical properties of ZnO–SnO2 nanocomposites synthesized by co-precipitation method

International Nuclear Information System (INIS)

Baitha, Pankaj Kr.; Pal, Partha P.; Manam, J.

2014-01-01

In this study an effort has been made to investigate the dosimetric sensing and optical properties of ZnO–SnO 2 nanocomposites at different pH values. The nanocomposites samples are irradiated by X-ray and then thermoluminescence (TL) analysis is carried out to investigate the response. The structural details of nanocomposites are characterized by Scanning Electron microscope, X-Ray Powder Diffraction and Fourier Transform Infrared Spectroscopy. Similarly, optical properties were characterized by UV–vis spectroscopy and Photoluminescence spectroscopy. The XRD studies revealed good crystallnity of samples with presence of both phases, ZnO as well as SnO 2 simultaneously. The SEM image revealed nanoflakes and nanoflower shape of ZnO–SnO 2 nanocomposite for sample synthesized at pH 7. Also, nanocube and nanosphere can be seen at higher pH value of 9. The room temperature photoluminescence spectra of ZnO–SnO 2 nanocomposite contain multi peaks at 398 nm, 410 nm, 451 nm, 469 nm, 484 nm, 493 nm and 545 nm at an excitation wavelength of 225 nm, which arises mainly due to oxygen and zinc related defects. The TL glow curve shows intense glow peaks at 346°, 261°, 209° and 153° for the samples synthesized at pH 3, pH 5, pH 7 and pH 9 respectively. The peaks are found to be increased with higher pH values. The peaks are found to be shifted towards lower temperature with higher pH values. The study shows that the ZnO–SnO 2 nano-composite is more developed material than singly ZnO compound or SnO 2 with enhanced opto-electronic and thermal properties and great applications in thermal dosimetry. - Highlights: • ZnO–CNT nanocomposites prepared by coprecipitation method at different pH values. • Sample at different pH show different nanostructures as revealed by SEM. • PL spectra indicate intense peaks related to O 2 and Zn defects for all samples. • TL spectra show peak shift with increasing pH values of samples. • ZnO–CNTs are very effective for both

Physical-chemical property based sequence motifs and methods regarding same

Science.gov (United States)

Braun, Werner [Friendswood, TX; Mathura, Venkatarajan S [Sarasota, FL; Schein, Catherine H [Friendswood, TX

2008-09-09

A data analysis system, program, and/or method, e.g., a data mining/data exploration method, using physical-chemical property motifs. For example, a sequence database may be searched for identifying segments thereof having physical-chemical properties similar to the physical-chemical property motifs.

The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

International Nuclear Information System (INIS)

Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

2015-01-01

Three different internal mixing methods (Core–Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20–70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20–50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core–Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC–sulfate aerosol is about –3.18 W/m 2 for the external method and –6.91 W/m 2 for the internal methods at the surface, and –3.03/–1.56/–1.85 W/m 2 for the external/Core–Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause. - Highlights: • The aerosol optical properties with different mixing

Field emission properties of nano-structured cobalt ferrite (CoFe2O4) synthesized by low-temperature chemical method

Science.gov (United States)

Ansari, S. M.; Suryawanshi, S. R.; More, M. A.; Sen, Debasis; Kolekar, Y. D.; Ramana, C. V.

2018-06-01

We report on the field-emission properties of structure-morphology controlled nano-CoFe2O4 (CFO) synthesized via a simple and low-temperature chemical method. Structural analyses indicate that the spongy-CFO (approximately, 2.96 nm) is nano-structured, spherical, uniformly-distributed, cubic-structured and porous. Field emission studies reveal that CFO exhibit low turn-on field (4.27 V/μm) and high emission current-density (775 μA/cm2) at a lower applied electric field of 6.80 V/μm. In addition, extremely good emission current stability is obtained at a pre-set value of 1 μA and high emission spot-density over large area (2 × 2 cm2) suggesting the applicability of these materials for practical applications in vacuum micro-/nano-electronics.

Photocatalytical Properties and Theoretical Analysis of N, Cd-Codoped TiO2 Synthesized by Thermal Decomposition Method

Directory of Open Access Journals (Sweden)

Hongtao Gao

2012-01-01

Full Text Available N, Cd-codoped TiO2 have been synthesized by thermal decomposition method. The products were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, UV-visible diffuse reflectance spectra (DRS, X-ray photoelectron spectroscopy (XPS, and Brunauer-Emmett-Teller (BET specific surface area analysis, respectively. The products represented good performance in photocatalytic degradation of methyl orange. The effect of the incorporation of N and Cd on electronic structure and optical properties of TiO2 was studied by first-principle calculations on the basis of density functional theory (DFT. The impurity states, introduced by N 2p or Cd 5d, lied between the valence band and the conduction band. Due to dopants, the band gap of N, Cd-codoped TiO2 became narrow. The electronic transition from the valence band to conduction band became easy, which could account for the observed photocatalytic performance of N, Cd-codoped TiO2. The theoretical analysis might provide a probable reference for the experimentally element-doped TiO2 synthesis.

Effects of Environmental Surface Modification Methods on Physical Properties of Hemp Fibers

Directory of Open Access Journals (Sweden)

Nigar MERDAN

2017-11-01

Full Text Available In this study, hemp fibers have been pre-treated with laccase enzyme in different concentrations (1%, 2% and 3% w/v for different durations using conventional, ultrasonic energy and microwave energy methods. Weight loss (%, tensile strength, elongation (%, whiteness (%, and surface topography (SEM properties of pre-treated hemp fibers were investigated. After processing with laccase enzyme, the energy consumptions of these three methods were compared. Best results have been obtained in 20 minutes with the conventional method, 5 minutes with the ultrasonic energy method, and 1 minute with the microwave energy method. With laccase enzyme, microwave treated hemp fibers were improved after 3 minutes treatment. SEM results have also proved the improved physical properties and color changes due to the rough surface structure. DOI: http://dx.doi.org/10.5755/j01.ms.23.4.17469

Measurement of uranium dioxide thermophysical properties by the laser flash method

International Nuclear Information System (INIS)

Grossi, Pablo Andrade; Ferreira, Ricardo Alberto Neto; Camarano, Denise das Merces; Andrade, Roberto Marcio de

2009-01-01

The evaluation of the thermophysical properties of uranium dioxide (UO 2 ), including a reliable uncertainty assessment, are required by the nuclear reactor design. These important information are used by thermohydraulic codes to define operational aspects and to assure the safety, when analyzing various potential situations of accident. The laser flash method had become the most popular method to measure the thermophysical properties of materials. Despite its several advantages, some experimental obstacles have been found due to the difficulty to obtain experimentally the ideals initial and boundary conditions required by the original method. An experimental apparatus and a methodology for estimating uncertainties of thermal diffusivity, thermal conductivity and specific heat measurements based on the laser flash method are presented. A stochastic thermal diffusion modeling has been developed and validated by standard samples. Inverse heat conduction problems (IHCPs) solved by finite volumes technique were applied to the measurement process with real initial and boundary conditions, and Monte Carlo Method was used for propagating the uncertainties. The main sources of uncertainty were due to: pulse time, laser power, thermal exchanges, absorptivity, emissivity, sample thickness, specific mass and dynamic influence of temperature measurement system. As results, mean values and uncertainties of thermal diffusivity, thermal conductivity and specific heat of UO 2 are presented. (author)

Mechanical properties investigation on single-wall ZrO2 nanotubes: A finite element method with equivalent Poisson's ratio for chemical bonds

Science.gov (United States)

Yang, Xiao; Li, Huijian; Hu, Minzheng; Liu, Zeliang; Wärnå, John; Cao, Yuying; Ahuja, Rajeev; Luo, Wei

2018-04-01

A method to obtain the equivalent Poisson's ratio in chemical bonds as classical beams with finite element method was proposed from experimental data. The UFF (Universal Force Field) method was employed to calculate the elastic force constants of Zrsbnd O bonds. By applying the equivalent Poisson's ratio, the mechanical properties of single-wall ZrNTs (ZrO2 nanotubes) were investigated by finite element analysis. The nanotubes' Young's modulus (Y), Poisson's ratio (ν) of ZrNTs as function of diameters, length and chirality have been discussed, respectively. We found that the Young's modulus of single-wall ZrNTs is calculated to be between 350 and 420 GPa.

Structural, optical, and thermal properties of MAX-phase Cr2AlB2

Science.gov (United States)

Li, Xiao-Hong; Cui, Hong-Ling; Zhang, Rui-Zhou

2018-04-01

First-principles calculations of the structural, optical, and thermal properties of Cr2AlB2 are performed using the pseudopotential plane-wave method within the generalized gradient approximation (GGA). Calculation of the elastic constant and phonon dispersion indicates that Cr2AlB2 is mechanically and thermodynamically stable. Analysis of the band structure and density of states indicates that Cr2AlB2 is metallic. The thermal properties under increasing temperature and pressure are investigated using the quasi-harmonic Debye model. The results show that anharmonic effects on Cr2AlB2 are important at low temperature and high pressure. The calculated equilibrium primitive cell volume is 95.91 Å3 at T = 300 K, P = 0 GPa. The ability of Cr2AlB2 to resist volume changes becomes weaker with increasing temperature and stronger with increasing pressure. Analysis of optical properties of Cr2AlB2 shows that the static dielectric function of Cr2AlB2 is 53.1, and the refractive index n 0 is 7.3. If the incident light has a frequency exceeding 16.09 eV, which is the plasma frequency of Cr2AlB2, Cr2AlB2 changes from metallic to dielectric material.

Thermoelectric properties of unoxidized graphene/Bi{sub 2}Te{sub 2.7}Se{sub 0.3} composites synthesized by exfoliation/re-assembly method

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Il; Lee, Eun Sil; Kim, Jong-Young [Icheon Branch, Korea Institute of Ceramic Engineering and Technology, Gyeonggi-do (Korea, Republic of); Choi, Soon-Mok [School of Energy, Materials and Chemical Engineering, Korea University of Technology and Education, Cheonan (Korea, Republic of); Lee, Kyu Hyoung [Materials R and D Center, Samsung Advanced Institute of Technology, Yongin (Korea, Republic of); Seo, Won-Seon [Energy and Environmental Division, Korea Institute of Ceramic Engineering and Technology, Seoul (Korea, Republic of)

2014-04-15

Nanocomposites of n-type thermoelectric Bi{sub 2}Te{sub 2.7}Se{sub 0.3} (BTS) and unoxidized graphene (UG) were prepared from the exfoliated BTS and UG nanoplatelets. Polycrystalline BTS ingots were exfoliated into nanoscroll-type crystals by chemical exfoliation, and were re-assembled with UG nanoplatelets. The composites were chemically reduced by hydrazine hydrate and sintered by a spark-plasma-sintering method. The thermoelectric properties of the sintered composites were evaluated and exhibited decreased carrier concentration and increased thermal conductivity due to the embedded graphene. The peak ZT values for the UG/BTS-US and UG/BTS-EX composites were ∝0.8 at the UG concentration of 0.05 wt%. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Controlling the size and magnetic properties of nano CoFe2O4 by microwave assisted co-precipitation method

Science.gov (United States)

Prabhakaran, T.; Mangalaraja, R. V.; Denardin, Juliano C.

2018-02-01

In this report, cobalt ferrite nanoparticles synthesized using microwave assisted co-precipitation method was reported. Efforts have been made to control the particles size, distribution, morphology and magnetic properties of cobalt ferrite nanoparticles by varying the concentration of NaOH solution and microwave irradiation time. It was observed that the rate of nucleation and crystal growth was influenced by the tuning parameters. In that way, the average crystallite size of single phase cobalt ferrite nanoparticles was controlled within 9-11 and 10-12 nm with an increase of base concentration and microwave irradiation time, respectively. A narrow size distribution of nearly spherical nanoparticles was achieved through the present procedure. A soft ferromagnetism at room temperature with the considerable saturation magnetization of 58.4 emu g-1 and coercivity of 262.7 Oe was obtained for the cobalt ferrites synthesized with 2.25 M of NaOH solution for 3 and 7 min of microwave irradiation time, respectively. The cobalt ferrite nanoparticles synthesized with a shorter reaction time of 3-7 min was found to be advantageous over other methods that involved conventional heating procedures and longer reaction time to achieve the better magnetic properties for the technological applications.

Thermodynamic properties of organic compounds estimation methods, principles and practice

CERN Document Server

Janz, George J

1967-01-01

Thermodynamic Properties of Organic Compounds: Estimation Methods, Principles and Practice, Revised Edition focuses on the progression of practical methods in computing the thermodynamic characteristics of organic compounds. Divided into two parts with eight chapters, the book concentrates first on the methods of estimation. Topics presented are statistical and combined thermodynamic functions; free energy change and equilibrium conversions; and estimation of thermodynamic properties. The next discussions focus on the thermodynamic properties of simple polyatomic systems by statistical the

Measurement properties of existing clinical assessment methods evaluating scapular positioning and function. A systematic review

DEFF Research Database (Denmark)

Larsen, Camilla Marie; Juul-Kristensen, Birgit; Lund, Hans

%), with only one study rated as ‘good’. The reliability domain was most often investigated. Fewof the assessment methods in the included studies that had ‘fair’ or ‘good’ measurement properties demonstrated acceptable results for both reliability and validity.ConclusionWe found a substantially larger number......ABSTRACT OARSI Measurement properties of existing clinical assessment methods evaluating scapular positioning and function. A systematic review Larsen CM1, Juul-Kristensen B1,2 Lund H1,2, Søgaard K11University of Southern Denmark, Institute of Sports Science and Clinical Biomechanics2Institute...... assessment methods have measured the degree of scapular dyskinesis, subjectively by visual evaluation and objectively by measurements of static and dynamic scapular positioning, by either a 3-dimensional electromagnetic device or 2-dimensional clinically applicable methods. Since advanced equipment (i.e. 3D...

Effect of metal ion dopants on photochemical properties of anatase TiO{sub 2} films synthesized by a modified sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Yuan Zhangfu [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)]. E-mail: yuanzhf@home.ipe.ac.cn; Zhang Junling [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Bin [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Jianqiang [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)

2007-06-25

Anatase TiO{sub 2} films were successfully synthesized by a modified sol-gel method wherein peroxo titanic acid solution was derived from TiCl{sub 4}/ethanol/water solution at room temperature. The as-prepared films were further surface-doped by photodeposited Fe{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} to improve its physicochemical properties. The phase and structure of the films were investigated by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The physicochemical properties of the films were also measured. The results show that both hydrophilicity and photocatalytic activity of the films were remarkably improved by doping transition metal ion Fe{sup 3+}. In case of Cr{sup 3+} doped films, hydrophilicity was also significantly enhanced but photocatalytic activity for methyl orange under UV irradiation was still comparable with the undoped films.

Synthesis and Microstructure Properties of (Bi,Pb2Sr2Ca1Cu2Oy Ceramic Superconductor

Directory of Open Access Journals (Sweden)

nurmalita .

2015-11-01

Full Text Available Properties of (Bi, Pb2Sr2Ca1Cu2Oy ceramic superconductors were prepared by the melt textured growth methods in order to investigate the effects of the slow cooling time on the microstructur.  Phase analyses of the samples by X-ray diffraction (XRD has been carried out to assess the effects of the slow cooling time. From XRD analyses, the addition to the sample of  the slow cooling time degrades formation of the high-Tc Bi-2212 phase. The possible reasons for the observed degradation in the microstructure properties due to the slow cooling time addition were discussed.

The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

Science.gov (United States)

Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

2015-08-01

Three different internal mixing methods (Core-Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20-70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20-50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core-Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC-sulfate aerosol is about -3.18 W/m2 for the external method and -6.91 W/m2 for the internal methods at the surface, and -3.03/-1.56/-1.85 W/m2 for the external/Core-Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause.

Cytotoxicity and genotoxicity properties of particulate matter fraction 2.5 μm

Science.gov (United States)

Bełcik, Maciej K.; Trusz-Zdybek, Agnieszka; Zaczyńska, Ewa; Czarny, Anna; Piekarska, Katarzyna

2017-11-01

In the ambient is more than 2,000 chemical substances, some of them are absorbed on the surface of the particulate matter and may causes many health problems. Air pollution is responsible for more than 3.2 million premature deaths which classifies it as a second place environmental risk factor. Especially dangerous for health are polycyclic aromatic hydrocarbons and their nitro- and amino derivatives which shows mutagenic and carcinogenic properties. Air pollutions were also classified by International Agency for Research on Cancer to group which carcinogenic properties on human were proved by available knowledge. Air pollutions, including particulate matter are one of the biggest problem in Polish cities. World Health Organization in report published in May 2016 set many of Polish cities on the top of the list most polluted in European Union. The article presents results of mutagenicity, genotoxicity and cytotoxicity researches conducted on a particulate matter fraction 2.5 μm collected during all year long in Wroclaw agglomeration. The material were collected on filters using high-flow air aspirator and extracted using dichloromethane. Additionally it was fractionated into 2 parts containing: all pollutants and only polycyclic aromatic hydrocarbons. Dry residue of this fractions were dissolving in DMSO and tested using biological methods. Biological methods include mutagenicity properties which are investigated by Salmonella assay (Ames assay). Other biological method was comet assay and 4 parameter cytotoxicity test PAN-I assay. Results of the conducted experiments shows differences in mutagenic, genotoxic and cytotoxic properties between seasons of collection and between volume of dust pollutions fractions. The worst properties shows particles collected in autumn and winter season and this containing only polycyclic aromatics hydrocarbons. Results showed also some correlations in results obtained during different methods and properties.

Structure and electrochemical properties of Mg2SnO4 nanoparticles synthesized by a facile co-precipitation method

International Nuclear Information System (INIS)

Tang, Hao; Cheng, Cuixia; Yu, Gaige; Liu, Haowen; Chen, Weiqing

2015-01-01

Nanosized Mg 2 SnO 4 has been synthesized by a facile co-precipitation method. The structure and morphology of the as-prepared samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), fourier Transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is found that Mg 2 SnO 4 sample is very sensitive to the aging time of the precursor. The single phase Mg 2 SnO 4 nanoparticles with ∼23 nm can be obtained at 900 °C using the aging 35 min percusor as source. The electrochemical properties of the powder obtained at 900 °C are investigated by galvanostatic discharge-charge tests and cyclic voltammograms (CVs). The initial specific discharge capacity reaches as high as 927.7 mAh g −1 at 0.2 mA cm −2 in 0.05–3.0 V, which indicates that Mg 2 SnO 4 nanoparticles could be a promising candidate of anode material for Li-ion batteries. - Highlights: • Nanosized Mg 2 SnO 4 has been synthesized by a facile co-precipitation method. • We find that Mg 2 SnO 4 sample is very sensitive to the ageing time of the precursor. • The single phase Mg 2 SnO 4 nanoparticles with about 23 nm can be obtained by calcining the ageing 35 min percusor at 900 °C. • The obtained powders show a better electrochemical performance

Synthesis and luminescence properties of Eu"2"+ doped CaSO_4 phosphor

International Nuclear Information System (INIS)

Aghalte, G.A.; Dhoble, S.J.; Pawar, N.R.

2016-01-01

Eu"2"+ doped CaSO_4 Phosphor were synthesized by precipitation method. PL analysis of Eu"2"+ activated CaSO_4 phosphor exhibited characteristic emission properties; CaSO_4:Eu Phosphor has received considerable attention because of its high sensitivity to X-ray and λ ray irradiation. CaSO_4:Eu phosphor powder was successfully synthesized by the wet chemical co-precipitation method. The structure morphology and luminescent properties of the phosphor were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy

Superior Gas Sensing Properties of Monolayer PtSe2

KAUST Repository

Sajjad, Muhammad

2016-12-15

First-principles calculations of the structural and electronic properties of monolayer 1T-PtSe2 with adsorbed (a) NO2, (b) NO, (c) NH3, (d) H2O, (e) CO2, and (f) CO molecules are discussed. The results point to great potential of the material in gas sensor applications. Superior sensitivity is demonstrated by transport calculations using the nonequilibrium Green\\'s function method.

Property Valuation: Integration of Methods and Determination of Depreciation

NARCIS (Netherlands)

Tempelmans Plat, H.; Verhaegh, M.

2000-01-01

Property valuation up to now is a global guess. On the one hand we have the Investment Method which regards a property as just a sum of money, on the other hand we have the Contractor's Method which is based on the actual new construction costs of the building and the actual value of the land. Both

The investigation of dependences of mechanical and electronic properties of TiB2 on pressure using the first-principles method

International Nuclear Information System (INIS)

Wang, Mingliang

2014-01-01

This work studied the dependences of the mechanical and electronic properties of TiB 2 on pressures using the first-principles method, based on the density functional theory. The results showed that pressure has a profound impact on the structural, mechanical and electronic properties of TiB 2 . The calculated structural and mechanical parameters (i.e. bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and Debye temperature) were in good agreement with both the available experimental and theoretical results at zero pressure. In addition, the mechanical parameters presented linearly increasing dependences on external pressure. Through the analysis of the density of states and Mulliken charges, the interlayer bonding in TiB 2 should be formed in a complex manner. There were three origins for the interlayer interactions between the B and Ti atomic layers: (a) planar Bsp 2 covalent bonding of moderate hybridizing with the Ti3d state −9.94 eV of the bonding state; (b) strong B2p and Ti3d hybridization of covalent bonding at −3.13 eV of the bonding state; (c) ionic bonding between Ti and B atoms. These interactions between the B and Ti interlayers determined the high hardness and high melting point of TiB 2 . As the pressures elevated, the charge transfer between Ti and B atoms increased, and the B–B and Ti–B bond lengths all decreased in accordingly. Thus, it was concluded that the ionic and covalent bonds can be strengthened. This could be responsible for causing the enhanced mechanical properties in TiB 2 . As for the metallicity, the quantity of charges of free-electron transfer from Tis to Ti3p and Ti3d states remained level, leading to no change of electric conductivity in TiB 2 under high pressures. (paper)

The investigation of dependences of mechanical and electronic properties of TiB2 on pressure using the first-principles method

Science.gov (United States)

Wang, Mingliang

2014-11-01

This work studied the dependences of the mechanical and electronic properties of TiB2 on pressures using the first-principles method, based on the density functional theory. The results showed that pressure has a profound impact on the structural, mechanical and electronic properties of TiB2. The calculated structural and mechanical parameters (i.e. bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and Debye temperature) were in good agreement with both the available experimental and theoretical results at zero pressure. In addition, the mechanical parameters presented linearly increasing dependences on external pressure. Through the analysis of the density of states and Mulliken charges, the interlayer bonding in TiB2 should be formed in a complex manner. There were three origins for the interlayer interactions between the B and Ti atomic layers: (a) planar Bsp2 covalent bonding of moderate hybridizing with the Ti3d state -9.94 eV of the bonding state; (b) strong B2p and Ti3d hybridization of covalent bonding at -3.13 eV of the bonding state; (c) ionic bonding between Ti and B atoms. These interactions between the B and Ti interlayers determined the high hardness and high melting point of TiB2. As the pressures elevated, the charge transfer between Ti and B atoms increased, and the B-B and Ti-B bond lengths all decreased in accordingly. Thus, it was concluded that the ionic and covalent bonds can be strengthened. This could be responsible for causing the enhanced mechanical properties in TiB2. As for the metallicity, the quantity of charges of free-electron transfer from Tis to Ti3p and Ti3d states remained level, leading to no change of electric conductivity in TiB2 under high pressures.

Structural properties of TiO2 nanomaterials

Science.gov (United States)

Kusior, Anna; Banas, Joanna; Trenczek-Zajac, Anita; Zubrzycka, Paulina; Micek-Ilnicka, Anna; Radecka, Marta

2018-04-01

The surface of solids is characterized by active, energy-rich sites that determine physicochemical interaction with gaseous and liquid media and possible applications in photocatalysis. The behavior of materials in such processes is related to their form and amount of various species, especially water and forms of oxygen adsorbed on the surface. The preparation of materials with controlled morphology, which includes modifications of the size, geometry, and composition, is currently an important way of optimizing properties, as many of them depend on not only the size and phase composition, but also on shape. Hydroxylated centers on the surface, which can be treated as trapping sites, are particularly significant. Water adsorbed on the surface bridging hydroxyl groups can distinctly modulate the properties of the surface of titania. The saturation of the surface with hydroxyl groups may improve the photocatalytic properties. TiO2 nanomaterials were obtained via different methods. SEM and TEM analysis were performed to study the morphology. The analysis of XRD and Raman data revealed a phase composition of obtained materials. To examine the surface properties, FTIR absorption spectra of TiO2 nanomaterials were recorded. The photocatalytic activity of titanium dioxide nanoparticles was investigated through the decomposition of methylene blue. It was demonstrated that each surface modification affects the amount of adsorbed hydroxyl groups. The different contributions of the two species to the ν(H2O) FTIR bands for different nanostructures result from the preparation conditions. It was noted that pre-adsorbed water (the surface-bridging hydroxyl) might significantly modulate the surface properties of the material. The increase in hydroxyl group density on the titanium dioxide surface enhances the effectiveness of the photocatalytic processes. It was demonstrated that flower-like titania obtained via hydrothermal synthesis exhibits the weakest catalytic activity, in

Optical Properties of the Fresnoite Ba2TiSi2O8 Single Crystal

Directory of Open Access Journals (Sweden)

Chuanying Shen

2017-02-01

Full Text Available In this work, using large-sized single crystals of high optical quality, the optical properties of Ba2TiSi2O8 were systematically investigated, including transmission spectra, refractive indices and nonlinear absorption properties. The crystal exhibits a high transmittance (>84% over a wide wavelength range from 340 to 2500 nm. The refractive indices in the range from 0.31256 to 1.01398 μm were measured, and Sellmeier’s equations were fitted by the least squares method. The nonlinear absorption properties were studied by using the open-aperture Z-scan technique, with a nonlinear absorption coefficient measured to be on the order of 0.257 cm/GW at the peak power density of 16.4 GW/cm2. Such high transmittance and wide transparency indicate that optical devices using the Ba2TiSi2O8crystal can be applied over a wide wavelength range. Furthermore, the small nonlinear absorption observed in Ba2TiSi2O8 will effectively increase the optical conversion efficiency, decreasing the generation of laser damage of the optical device.

Optical properties and crystal structure of Eu3+ -doped Y2O3 crystals prepared under different conditions and with different methods

International Nuclear Information System (INIS)

Chung, Yong Hwa; Jang, Ki Wan; Kim, Il Gon; Kim Sang Su; Lee, Yong Ill; Park, Seong Tae; Seo, Hyo Jin

2003-01-01

The optical properties and the crystal structure of 6-mol% Eu 3+ -doped Y 2 O 3 powders prepared under different conditions and with different methods were studied through emission spectroscopy and X-ray powder diffraction. All samples exhibited the normal fluorescence spectrum of Eu 3+ -doped cubic Y 2 O 3 powders. The peak positions of the 5 D 0 → 7 F 0 transitions of Eu 3+ ions were shifted to the short-wavelength direction as the sintering temperature was lowered or the size of the host particle itself was decreased. The dynamic properties, such as the rise or the decay time of the 5 D 0 → 7 F 2 transition, depended on other factors than the size of the grain contained in each particle and the size of host particle itself. The morphologies of the studied samples were also observed by using a scanning electron microscope

A primer of statistical methods for correlating parameters and properties of electrospun poly( l -lactide) scaffolds for tissue engineering-PART 2: Regression

KAUST Repository

Seyedmahmoud, Rasoul

2014-04-07

This two-articles series presents an in-depth discussion of electrospun poly-l-lactide scaffolds for tissue engineering by means of statistical methodologies that can be used, in general, to gain a quantitative and systematic insight about effects and interactions between a handful of key scaffold properties (Ys) and a set of process parameters (Xs) in electrospinning. While Part-1 dealt with the DOE methods to unveil the interactions between Xs in determining the morphomechanical properties (ref. Y1-4), this Part-2 article continues and refocuses the discussion on the interdependence of scaffold properties investigated by standard regression methods. The discussion first explores the connection between mechanical properties (Y4) and morphological descriptors of the scaffolds (Y1-3) in 32 types of scaffolds, finding that the mean fiber diameter (Y1) plays a predominant role which is nonetheless and crucially modulated by the molecular weight (MW) of PLLA. The second part examines the biological performance (Y5) (i.e. the cell proliferation of seeded bone marrow-derived mesenchymal stromal cells) on a random subset of eight scaffolds vs. the mechanomorphological properties (Y1-4). In this case, the featured regression analysis on such an incomplete set was not conclusive, though, indirectly suggesting in quantitative terms that cell proliferation could not fully be explained as a function of considered mechanomorphological properties (Y1-4), but in the early stage seeding, and that a randomization effects occurs over time such that the differences in initial cell proliferation performance (at day 1) is smeared over time. The findings may be the cornerstone of a novel route to accrue sufficient understanding and establish design rules for scaffold biofunctional vs. architecture, mechanical properties, and process parameters.

2-d Simulations of Test Methods

DEFF Research Database (Denmark)

Thrane, Lars Nyholm

2004-01-01

One of the main obstacles for the further development of self-compacting concrete is to relate the fresh concrete properties to the form filling ability. Therefore, simulation of the form filling ability will provide a powerful tool in obtaining this goal. In this paper, a continuum mechanical...... approach is presented by showing initial results from 2-d simulations of the empirical test methods slump flow and L-box. This method assumes a homogeneous material, which is expected to correspond to particle suspensions e.g. concrete, when it remains stable. The simulations have been carried out when...... using both a Newton and Bingham model for characterisation of the rheological properties of the concrete. From the results, it is expected that both the slump flow and L-box can be simulated quite accurately when the model is extended to 3-d and the concrete is characterised according to the Bingham...

PhySIC: a veto supertree method with desirable properties.

Science.gov (United States)

Ranwez, Vincent; Berry, Vincent; Criscuolo, Alexis; Fabre, Pierre-Henri; Guillemot, Sylvain; Scornavacca, Celine; Douzery, Emmanuel J P

2007-10-01

This paper focuses on veto supertree methods; i.e., methods that aim at producing a conservative synthesis of the relationships agreed upon by all source trees. We propose desirable properties that a supertree should satisfy in this framework, namely the non-contradiction property (PC) and the induction property (PI). The former requires that the supertree does not contain relationships that contradict one or a combination of the source topologies, whereas the latter requires that all topological information contained in the supertree is present in a source tree or collectively induced by several source trees. We provide simple examples to illustrate their relevance and that allow a comparison with previously advocated properties. We show that these properties can be checked in polynomial time for any given rooted supertree. Moreover, we introduce the PhySIC method (PHYlogenetic Signal with Induction and non-Contradiction). For k input trees spanning a set of n taxa, this method produces a supertree that satisfies the above-mentioned properties in O(kn(3) + n(4)) computing time. The polytomies of the produced supertree are also tagged by labels indicating areas of conflict as well as those with insufficient overlap. As a whole, PhySIC enables the user to quickly summarize consensual information of a set of trees and localize groups of taxa for which the data require consolidation. Lastly, we illustrate the behaviour of PhySIC on primate data sets of various sizes, and propose a supertree covering 95% of all primate extant genera. The PhySIC algorithm is available at http://atgc.lirmm.fr/cgi-bin/PhySIC.

Modeling Mechanical Properties of Aluminum Composite Produced Using Stir Casting Method

Directory of Open Access Journals (Sweden)

Muhammad Hayat Jokhio

2011-01-01

Full Text Available ANN (Artificial Neural Networks modeling methodology was adopted for predicting mechanical properties of aluminum cast composite materials. For this purpose aluminum alloy were developed using conventional foundry method. The composite materials have complex nature which posses the nonlinear relationship among heat treatment, processing parameters, and composition and affects their mechanical properties. These nonlinear relation ships with properties can more efficiently be modeled by ANNs. Neural networks modeling needs sufficient data base consisting of mechanical properties, chemical composition and processing parameters. Such data base is not available for modeling. Therefore, a large range of experimental work was carried out for the development of aluminum composite materials. Alloys containing Cu, Mg and Zn as matrix were reinforced with 1- 15% Al2O3 particles using stir casting method. Alloys composites were cast in a metal mold. More than eighty standard samples were prepared for tensile tests. Sixty samples were given solution treatments at 580oC for half an hour and tempered at 120oC for 24 hours. The samples were characterized to investigate mechanical properties using Scanning Electron Microscope, X-Ray Spectrometer, Optical Metallurgical Microscope, Vickers Hardness, Universal Testing Machine and Abrasive Wear Testing Machine. A MLP (Multilayer Perceptron feedforward was developed and used for modeling purpose. Training, testing and validation of the model were carried out using back propagation learning algorithm. The modeling results show that an architecture of 14 inputs with 9 hidden neurons and 4 outputs which includes the tensile strength, elongation, hardness and abrasive wear resistance gives reasonably accurate results with an error within the range of 2-7 % in training, testing and validation.

Modeling mechanical properties of aluminum composite produced using stir casting method

International Nuclear Information System (INIS)

Jokhio, M.H.; Panhwar, M.I.; Unar, M.A.

2011-01-01

ANN (Artificial Neural Networks) modeling methodology was adopted for predicting mechanical properties of aluminum cast composite materials. For this purpose aluminum alloy were developed using conventional foundry method. The composite materials have complex nature which posses the nonlinear relationship among heat treatment, processing parameters, and composition and affects their mechanical properties. These nonlinear relation ships with properties can more efficiently be modeled by ANNs. Neural networks modeling needs sufficient data base consisting of mechanical properties, chemical composition and processing parameters. Such data base is not available for modeling. Therefore, a large range of experimental work was carried out for the development of aluminum composite materials. Alloys containing Cu, Mg and Zn as matrix were reinforced with 1- 15% AI/sub 2/O/sub 3/ particles using stir casting method. Alloys composites were cast in a metal mold. More than eighty standard samples were prepared for tensile tests. Sixty samples were given solution treatments at 580 deg. C for half an hour and tempered at 120 deg. C for 24 hours. The samples were characterized to investigate mechanical properties using Scanning Electron Microscope, X-Ray Spectrometer, Optical Metallurgical Microscope, Vickers Hardness, Universal Testing Machine and Abrasive Wear Testing Machine. A MLP (Multilayer Perceptron) feed forward was developed and used for modeling purpose. Training, testing and validation of the model were carried out using back propagation learning algorithm. The modeling results show that an architecture of 14 inputs with 9 hidden neurons and 4 outputs which includes the tensile strength, elongation, hardness and abrasive wear resistance gives reasonably accurate results with an error within the range of 2-7 % in training, testing and validation. (author)

Diameter 2 properties and convexity

Czech Academy of Sciences Publication Activity Database

Abrahamsen, T. A.; Hájek, Petr Pavel; Nygaard, O.; Talponen, J.; Troyanski, S.

2016-01-01

Roč. 232, č. 3 (2016), s. 227-242 ISSN 0039-3223 R&D Projects: GA ČR GA16-07378S Institutional support: RVO:67985840 Keywords : diameter 2 property * midpoint locally uniformly rotund * Daugavet property Subject RIV: BA - General Mathematics Impact factor: 0.535, year: 2016 https://www.impan.pl/pl/wydawnictwa/czasopisma-i-serie-wydawnicze/studia- mathematica /all/232/3/91534/diameter-2-properties-and-convexity

Structural and transport properties of nanocrystalline MnFe/sub 2/O/sub 4/ synthesized by co-precipitation method

International Nuclear Information System (INIS)

Akhtar, M.J.; Younas, M.

2012-01-01

The nanocrystalline ferrites with spinel structures have been the focus of scientific investigation and received continuous interest in recent decades. The structural and electrical properties of these materials have become an important area of research and are attracting considerable interest due to broad range of applications. Spinel ferrites have been shown to exhibit interesting dielectric properties in the nanocrystalline form in comparison to the corresponding bulk materials. Structural and electrical properties of nanocrystalline MnFe/sub 2/O/sub 4/ were investigated. X-ray diffraction and X-ray absorption fine structure spectroscopy results showed that nanocrystalline MnFe/sub 2/O/sub 4/ had cubic symmetry with 80% inversion. shows the X-ray absorption near edge structure (XANES) spectra of MnFe/sub 2/O/sub 4/ and Zn/sub 1-x/Ni/sub x/Fe/sub 2/O/sub 4/, used as model compounds. The electrical transport properties were investigated by employing impedance spectroscopy. It was observed that the dielectric constant decreased with the increase in frequency. The effects of frequency on dielectric properties were more prominent in the low frequency region, where dielectric constant increased as temperature was increased. (Orig./A.B.)

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

International Nuclear Information System (INIS)

Manonukul, Anchalee; Srikudvien, Pathompoom; Tange, Makiko; Puncreobutr, Chedtha

2016-01-01

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

Energy Technology Data Exchange (ETDEWEB)

Manonukul, Anchalee, E-mail: anchalm@mtec.or.th [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Srikudvien, Pathompoom [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Tange, Makiko [Taisei Kogyo Thailand Co., Ltd., Room INC2d-409, Innovation Cluster 2 Building, Tower D, 141 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Puncreobutr, Chedtha [Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330 (Thailand)

2016-02-08

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Synthesis and Tribological Properties of WSe2Nanorods

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Yang Jinghai

2008-01-01

Full Text Available Abstract The WSe2nanorods were synthesized via solid-state reaction method and characterized by X-ray diffractometer, TEM, and HRTEM. The results indicated the WSe2compounds had rod-like structures with diameters of 10–50 nm and lengths of 100–400 nm, and the growth process of WSe2nanorods was discussed on the basis of the experimental facts. The tribological properties of WSe2nanorods as additives in HVI500 base oil were investigated by UMT-2 multispecimen tribotester. Under the determinate conditions, the friction coefficient of the base oil containing WSe2nanorods was lower than that of the base oil, and decreased with increasing mass fraction of WSe2nanorods when it was <7 wt.%. Moreover, the base oil with the additives was rather suited to high load and high rotating speed. A combination of rolling friction, sliding friction, and stable tribofilm on the rubbing surface could explain the good friction and wear properties of WSe2nanorods as additives.

Effects of Synthesis Method on Electrical Properties of Graphene

Science.gov (United States)

Fuad, M. F. I. Ahmad; Jarni, H. H.; Shariffudin, W. N.; Othman, N. H.; Rahim, A. N. Che Abdul

2018-05-01

The aim of this study is to achieve the highest reduction capability and complete reductions of oxygen from graphene oxide (GO) by using different type of chemical methods. The modification of Hummer’s method has been proposed to produce GO, and hydrazine hydrate has been utilized in the GO’s reduction process into graphene. There are two types of chemical method are used to synthesize graphene; 1) Sina’s method and 2) Sasha’s method. Both GO and graphene were then characterized using X-Ray Powder Diffraction (XRD) and Fourier Transform Infrared Spectrometry (FT-IR). The graph patterns obtained from XRD showed that the values of graphene and GO are within their reliable ranges, FT-IR identified the comparison functional group between GO and graphene. Graphene was verified to experience the reduction process due to absent of functional group consist of oxygen has detected. Electrochemical impedance spectrometry (EIS) was then conducted to test the ability of conducting electricity of two batches (each weighted 1.6g) of graphene synthesized using different methods (Sina’s method and Sasha’s method). Sasha’s method was proven to have lower conductivity value compare to Sina’s method, with value of 6.2E+02 S/m and 8.1E+02 S/m respectively. These values show that both methods produced good graphene; however, by using Sina’s method, the graphene produced has better electrical properties.

Electronic structure and optical properties of Sr{sub 2}SnO{sub 4} studied with FP-LAPW method in density functional theory

Energy Technology Data Exchange (ETDEWEB)

Prijamboedi, B., E-mail: boedi@chem.itb.ac.id; Umar, S.; Failamani, F. [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2015-04-16

Oxide material of Sr{sub 2}SnO{sub 4}, when it is doped with Ti becomes a phosphor material that can emit intense blue light at room temperature. It is important to study the electronic structure of this material in order to determine the optical processes that occur in Ti-doped Sr{sub 2}SnO{sub 4}. Electronic structure and optical properties of Sr{sub 2}SnO{sub 4} is studied using density functional theory framework with full potential linearized augmented plane waves plus local orbitals (FP-LAPW+lo) method. We use modified Becke-Johnson (mBJ) exchange-correlation potential to calculate the energy gap. Our calculation showed that Sr{sub 2}SnO{sub 4} has indirect band gap with band gap energy of around 4.2 eV. The experimental absorption spectra of Sr{sub 2}SnO{sub 4} indicated that this oxide has band gap of around 4.6 eV and it is closer to the results given by mBJ exchange-correlation potential. We also studied other optical properties of Sr{sub 2}SnO{sub 4} and it is found in agreement with the experimental results.

Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

International Nuclear Information System (INIS)

Yang, C.; Liu, C.Z.; Wang, C.M.; Zhang, W.G.; Jiang, J.S.

2012-01-01

Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2−x Ba x FeO 3 (x=0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral (x=0) to orthorhombic (x=0.07–0.19) and then to tetragonal (x=0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r /M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe. - Highlights: ► Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles were prepared using a sol–gel method. ► The magnetic properties of the nanoparticles are greatly improved. ► The Neel temperature (T N ) of the nanoparticles is greatly increased. ► Doped ions and crystal structure affect the dielectric properties of the nanoparticles.

Optimizing Properties of Aluminum-Based Nanocomposites by Genetic Algorithm Method

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M.R. Dashtbayazi

2015-07-01

Full Text Available Based on molecular dynamics simulation results, a model was developed for determining elastic properties of aluminum nanocomposites reinforced with silicon carbide particles. Also, two models for prediction of density and price of nanocomposites were suggested. Then, optimal volume fraction of reinforcement was obtained by genetic algorithm method for the least density and price, and the highest elastic properties. Based on optimization results, the optimum volume fraction of reinforcement was obtained equal to 0.44. For this optimum volume fraction, optimum Young’s modulus, shear modulus, the price and the density of the nanocomposite were obtained 165.89 GPa, 111.37 GPa, 8.75 $/lb and 2.92 gr/cm3, respectively.

Tuning electronic properties of In2O3 nanowires by doping control

International Nuclear Information System (INIS)

Lei, B.; Li, C.; Zhang, D.; Tang, D.; Zhou, C.

2004-01-01

We present two effective routes to tune the electronic properties of single-crystalline In 2 O 3 nanowires by controlling the doping. The first method involves using different O 2 concentrations during the synthesis. Lightly (heavily) doped nanowires were produced by using high (low) O 2 concentrations, respectively, as revealed by the conductances and threshold voltages of nanowire-based field-effect transistors. Our second method exploits post-synthesis baking, as baking heavily doped nanowires in ambient air led to suppressed conduction and a positive shift of the threshold voltage, whereas baking lightly doped nanowires in vacuum displayed the opposite behavior. Our approaches offer viable ways to tune the electronic properties of many nonstoichiometric metal oxide systems such as In 2 O 3 , SnO 2 , and ZnO nanowires for various applications

Development of Decontamination Methods using Liquid/Supercritical CO2

International Nuclear Information System (INIS)

Park, Kwang Heon; Koh, Moon Sung; Yoon, Chung Hyun; Kim, Hong Doo; Kim, Hak Won

1994-01-01

A major problem of nuclear energy is the production of radioactive wastes. Needs for more environmentally favorable method to decontaminate radioactive contaminants make the use of liquid/supercritical CO2 as a solvent medium. In removing radioactive metallic contaminants under CO2 solvent, two methods - use of chelating ligands and that of water in CO2 emulsion - are possible. In the chelating ligand method, a combination of ligands that can make synergistic effects seems important. We discuss about the properties of microemulsion formed by F-AOT. By adding acid in water core, decontamination of metallic parts, soils were possible

Physicochemical and Antioxidant Properties of Rice Bran Oils Produced from Colored Rice Using Different Extraction Methods.

Science.gov (United States)

Mingyai, Sukanya; Kettawan, Aikkarach; Srikaeo, Khongsak; Singanusong, Riantong

2017-06-01

This study investigated the physicochemical and antioxidant properties of rice bran oil (RBO) produced from the bran of three rice varities; Khao Dawk Mali 105 (white rice), Red Jasmine rice (red rice) and Hom-nin rice (black rice) using three extraction methods including cold-press extraction (CPE), solvent extraction (SE) and supercritical CO 2 extraction (SC-CO 2 ). Yields, color, acid value (AV), free fatty acid (FFA), peroxide value (PV), iodine value (IV), total phenolic compound (TPC), γ-oryzanol, α-tocopherol and fatty acid profile were analyzed. It was found that the yields obtained from SE, SC-CO 2 and CPE extractions were 17.35-20.19%, 14.76-18.16% and 3.22-6.22%, respectively. The RBO from the bran of red and black rice samples exhibited high antioxidant activities. They also contained higher amount of γ-oryzanol and α-tocopherol than those of white rice sample. In terms of extraction methods, SC-CO 2 provided better qualities of RBO as evidenced by their physicochemical and antioxidant properties. This study found that RBO produced from the bran of black rice samples using SC-CO 2 extraction method showed the best physicochemical and antioxidant properties.

Effect of Preparation Method on Phase Formation Process and Structural and Magnetic Properties of Mn2.5Ge Samples

Directory of Open Access Journals (Sweden)

R. Sobhani

2016-12-01

Full Text Available In this paper, the phase formation process of Mn2.5Ge samples, prepared by mechanical alloying of Mn and Ge metal powders and annealing, has been studied. Results showed that in the milled samples the stable phase is Mn11Ge8 compound with orthorhombic structure and Pnam space group. The value of saturation magnetization increases by increasing milling time from 0.2 up to 1.95 (Am2Kg-1. The remanece of the samples increases by increasing the milling time while the coercivity decreases. Annealing of 15-hour milled sample results in disappearance of Mn and Ge and the formation of new phases of Mn3Ge, Mn5Ge2, Mn5Ge3 and Mn2.3Ge. Mn3Ge is the main phase with Do22 tetragonal structure and I4/mmm space group which is stable and dominant. The enhancement of saturation magnetization in the annealed sample is related to the formation of three new magnetic phases and the increase of coercivity is due to the presence of Mn3Ge compound with tetragonal structure. Studies were replicated on samples made by arc melting method to compare the results and to investigate the effect of the preparation method on phase formation and structural and magnetic properties of the materials. In these samples the saturation value was in range of 0.2 up to 1.95 (Am2Kg-1 depending on preparation methods. Rietveld refinement shows that Mn2.3Ge sample prepared from arc melted under 620oC anealing is single phase. Magnetic analysis of this sample show a saturation magnetization of 5.252(Am2Kg-1 and 0.005 T coercive field.

Growth and properties of oxygen doped Bi2Sr2CaCu2O8+δ single crystals

International Nuclear Information System (INIS)

Kapitulnik, A.; Mitzi, D.B.

1990-01-01

This paper reports results on oxygen doped single crystals in the Bi 2 Sr 2 CaCu 2 O 8+δ system grown by a directional solidification method. Annealing of as made crystals in increasing partial pressure of oxygen reversibly depresses the superconducting transition temperature from 90K (as made) to 77K (oxygen pressure annealed). Magnetic and photoemission properties of these crystals will be discussed

Random 2D Composites and the Generalized Method of Schwarz

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Vladimir Mityushev

2015-01-01

Full Text Available Two-phase composites with nonoverlapping inclusions randomly embedded in matrix are investigated. A straightforward approach is applied to estimate the effective properties of random 2D composites. First, deterministic boundary value problems are solved for all locations of inclusions, that is, for all events of the considered probabilistic space C by the generalized method of Schwarz. Second, the effective properties are calculated in analytical form and averaged over C. This method is related to the traditional method based on the average probabilistic values involving the n-point correlation functions. However, we avoid computation of the correlation functions and compute their weighted moments of high orders by an indirect method which does not address the correlation functions. The effective properties are exactly expressed through these moments. It is proved that the generalized method of Schwarz converges for an arbitrary multiply connected doubly periodic domain and for an arbitrary contrast parameter. The proposed method yields an algorithm which can be applied with symbolic computations. The Torquato-Milton parameter ζ1 is exactly written for circular inclusions.

Thermodynamic properties of Mg2Si and Mg2Ge investigated by first principles method

International Nuclear Information System (INIS)

Wang, Hanfu; Jin, Hao; Chu, Weiguo; Guo, Yanjun

2010-01-01

The lattice dynamics and thermodynamic properties of Mg 2 Si and Mg 2 Ge are studied based on the first principles calculations. We obtain the phonon dispersion curves and phonon density of states spectra using the density functional perturbation theory with local density approximations. By employing the quasi-harmonic approximation, we calculate the temperature dependent Helmholtz free energy, bulk modulus, thermal expansion coefficient, specific heat, Debye temperature and overall Grueneisen coefficient. The results are in good agreement with available experimental data and previous theoretical studies. The thermal conductivities of both compounds are then estimated with the Slack's equation. By carefully choosing input parameters, especially the acoustic Debye temperature, we find that the calculated thermal conductivities agree fairly well with the experimental values above 80 K for both compounds. This demonstrates that the lattice thermal conductivity of simple cubic semiconductors may be estimated with satisfactory accuracy by combining the Slack's equation with the necessary thermodynamics parameters derived completely from the first principles calculations.

Mechanical properties of CO2/MIG welded structural rolled steel and stainless steel

International Nuclear Information System (INIS)

Lim, Jong Young; Yoon, Myong Jin; Kim, Sang Youn; Kim, Tae Gyu; Shin, Hyeon Seung

2015-01-01

To accomplish long-term use of specific parts of steel, welding technology is widely applied. In this study, to compare the efficiency in improving mechanical properties, rolled steel (SS400) was welded with stainless steel (STS304) by both CO 2 welding method and MIG (metal inert gas) welding method, respectively. Multi-tests were conducted on the welded specimen, such as X-ray irradiation, Vickers' Hardness, tensile test, fatigue test and fatigue crack growth test. Based on the fatigue crack growth test performed by two different methods, the relationship of da/dN was analyzed. Although the hardness by the two methods was similar, tensile test and fatigue properties of MIG welded specimen are superior to CO 2 welded one.

Improved Dehydrogenation Properties of 2LiNH2-MgH2 by Doping with Li3AlH6

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Shujun Qiu

2017-01-01

Full Text Available Doping with additives in a Li-Mg-N-H system has been regarded as one of the most effective methods of improving hydrogen storage properties. In this paper, we prepared Li3AlH6 and evaluated its effect on the dehydrogenation properties of 2LiNH2-MgH2. Our studies show that doping with Li3AlH6 could effectively lower the dehydrogenation temperatures and increase the hydrogen content of 2LiNH2-MgH2. For example, 2LiNH2-MgH2-0.1Li3AlH6 can desorb 6.43 wt % of hydrogen upon heating to 300 °C, with the onset dehydrogenation temperature at 78 °C. Isothermal dehydrogenation testing indicated that 2LiNH2-MgH2-0.1Li3AlH6 had superior dehydrogenation kinetics at low temperature. Moreover, the release of byproduct NH3 was successfully suppressed. Measurement of the thermal diffusivity suggests that the enhanced dehydrogenation properties may be ascribed to the fact that doping with Li3AlH6 could improve the heat transfer for solid–solid reaction.

Semi-convergence properties of Kaczmarz’s method

International Nuclear Information System (INIS)

Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

2014-01-01

Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges very quickly toward a good approximation of the exact solution, and thus produces a regularized solution. While this property is generally accepted and utilized, there is surprisingly little theoretical justification for it. The purpose of this paper is to present insight into the semi-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging. (paper)

CoFe2O4 nanocrystalline powders prepared by citrate-gel methods: Synthesis, structure and magnetic properties

International Nuclear Information System (INIS)

Cannas, C.; Falqui, A.; Musinu, A.; Peddis, D.; Piccaluga, G.

2006-01-01

Nanocrystalline CoFe 2 O 4 powders were prepared by decomposition of metal ion citrate precursors. Four samples were synthesized from precursor solutions having different pH values in the range 2 physisorption and Transmission Electron Microscopy. Magnetic properties were explored by a SQUID magnetometer. Three out of the four samples, coming from solutions of pH 2, 4 and 7, were produced by an autocombustion reaction and are very similar as regards average size of the nanoparticles (about 20 nm), their morphology and the magnetic properties, while the fourth sample was produced by a slower thermal decomposition and is composed of smaller nanoparticles (about 10 nm)

Characterization and hydrogen gas sensing properties of TiO{sub 2} thin films prepared by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Haidry, Azhar Ali [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava (Slovakia); Puskelova, Jarmila [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava (Slovakia); Plecenik, Tomas; Durina, Pavol; Gregus, Jan; Truchly, Martin; Roch, Tomas; Zahoran, Miroslav [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava (Slovakia); Vargova, Melinda [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava (Slovakia); Kus, Peter; Plecenik, Andrej [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava (Slovakia); Plesch, Gustav, E-mail: plesch@fns.uniba.sk [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava (Slovakia)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Preparation and characterization of hydrogen sensing TiO{sub 2} thin films by sol-gel method. Black-Right-Pointing-Pointer The annealing effect on the structure, electrical, optical and sensing properties was studied. Black-Right-Pointing-Pointer The best sensitivity show the films composed of rutile with grain size of {approx}100 nm. - Abstract: Thin films of titanium dioxide with thickness of about 150 nm were deposited by spin coating method on a sapphire substrate from a sol-gel and annealed at various temperatures (from 600 Degree-Sign C to 1000 Degree-Sign C). Structural, optical and hydrogen gas sensing properties of the films were investigated. The annealing temperatures from 600 to 800 Degree-Sign C led to anatase phase with grain size in the range of 14-28 nm. Further increase of the annealing temperature resulted in transformation to rutile phase with larger grain size of about 100-120 nm. The optical band gap tended to decrease with increasing annealing temperature. The estimated values of activation energy for charge transport were in the range of 0.6-1.0 eV for films annealed at temperatures from 600 Degree-Sign C to 800 Degree-Sign C and 0.37-0.38 eV for films annealed at 900 Degree-Sign C and 1000 Degree-Sign C. The films annealed at 900 Degree-Sign C and 1000 Degree-Sign C showed better hydrogen sensitivity, what can be at least partially caused by their higher surface roughness.

Compare the phase transition properties of VO2 films from infrared to terahertz range

Science.gov (United States)

Liang, Shan; Shi, Qiwu; Huang, Wanxia; Peng, Bo; Mao, Zhenya; Zhu, Hongfu

2018-06-01

VO2 with reversible semiconductor-metal phase transition properties is particularly available for the application in smart opto-electrical devices. However, there are rare reports on comparing its phase transition properties at different ranges. In this study, the VO2 films are designed with the similar crystalline structure and stoichiometry, but different morphologies by inorganic and organic sol-gel methods, and their phase transition characteristics are compared both at infrared and terahertz range. The results indicate that the VO2 film prepared by inorganic sol-gel method shows more compact nanostructure. It results in larger resistivity change, infrared and terahertz switching ratio in the VO2 film. Moreover, it presents that the phase transition intensity of VO2 film in terahertz range is more sensitive to its microstructure. This work is helpful for understanding the susceptibility of terahertz switching properties of VO2 to its microstructure. And it can provide insights for the applications of VO2 in terahertz smart devices.

Comments on Thermal Physical Properties Testing Methods of Phase Change Materials

Directory of Open Access Journals (Sweden)

Jingchao Xie

2013-01-01

Full Text Available There is no standard testing method of the thermal physical properties of phase change materials (PCM. This paper has shown advancements in this field. Developments and achievements in thermal physical properties testing methods of PCM were commented, including differential scanning calorimetry, T-history measurement, the water bath method, and differential thermal analysis. Testing principles, advantages and disadvantages, and important points for attention of each method were discussed. A foundation for standardized testing methods for PCM was made.

Optical properties of cerium oxide (CeO2) nanoparticles synthesized by hydroxide mediated method

Science.gov (United States)

Ali, Mawlood Maajal; Mahdi, Hadeel Salih; Parveen, Azra; Azam, Ameer

2018-05-01

The nanoparticles of cerium oxide have been successfully synthesized by hydroxide mediated method, using cerium nitrate and sodium hydroxide as precursors. The microstructural properties were analyzed by X-ray diffraction technique (XRD). The X-ray diffraction results show that the cerium oxide nanoparticles were in cubic structure. The optical absorption spectra of cerium oxide were recorded by UV-VIS spectrophotometer in the range of 320 to 600 nm and photoluminescence spectra in the range of 400-540 nm and have been presented. The energy band gap was determined by Tauc relationship. The crystallite size was determined from Debye-Scherer equation and came out to be 6.4 nm.

Thermal lens and interferometric method for glass transition and thermo physical properties measurements in Nd2O3 doped sodium zincborate glass.

Science.gov (United States)

Astrath, N G C; Steimacher, A; Rohling, J H; Medina, A N; Bento, A C; Baesso, M L; Jacinto, C; Catunda, T; Lima, S M; Karthikeyan, B

2008-12-22

In this work the time resolved thermal lens method is combined with interferometric technique, the thermal relaxation calorimetry, photoluminescence and lifetime measurements to determine the thermo physical properties of Nd(2)O(3) doped sodium zincborate glass as a function of temperature up to the glass transition region. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of electronic polarizability were determined. In conclusion, the results showed the ability of thermal lens and interferometric methods to perform measurements very close to the phase transition region. These techniques provide absolute values for the measured physical quantities and are advantageous when low scan rates are required.

A comparison of properties between carboxylated acrylic rubbers prepared by γ-ray irradiation and chemical method

International Nuclear Information System (INIS)

Wang Weiwei; Chang Zhenqi; Wang Mozhen; Zhang Zhicheng; Lv Pin

2006-01-01

Acrylic rubbers (ACM) carboxylated by acrylic acid or itaconic acid were prepared by 60 Co γ-ray or chemical-initiator (K 2 S 2 O 8 ) induced emulsion copolymerization. The polymers were characterized by Fourier transform infrared spectroscopy (FT-IR). Acid value, molecular weight and polydispersity index (PDI) of the polymers were determined by non-aqueous titration method and gel permeation chromatography (GPC), respectively. Vulcanization and mechanical properties of the filled ACM were studied by rheometric measurement, gel fraction analysis, mechanical property tests and dynamic mechanical thermal analysis (DMTA). The results show that the ACMs prepared by γ-ray irradiation have lower acid value, higher molecular weight and narrower PDI than chemically prepared ACMs of the same compositions. The itaconic acid carboxylated ACM has better cure characteristics and mechanical properties than the acrylic acid carboxylated ACM. The itaconic acid carboxylated ACM prepared by γ-ray irradiation has higher gel fraction and better cure characteristics as well as mechanical properties than that prepared by chemical method. (authors)

Estimation of magnetocaloric properties by using Monte Carlo method for AMRR cycle

International Nuclear Information System (INIS)

Arai, R; Fukuda, H; Numazawa, T; Tamura, R; Li, J; Saito, A T; Nakagome, H; Kaji, S

2015-01-01

In order to achieve a wide refrigerating temperature range in magnetic refrigeration, it is effective to layer multiple materials with different Curie temperatures. It is crucial to have a detailed understanding of physical properties of materials to optimize the material selection and the layered structure. In the present study, we discuss methods for estimating a change in physical properties, particularly the Curie temperature when some of the Gd atoms are substituted for non-magnetic elements for material design, based on Gd as a ferromagnetic material which is a typical magnetocaloric material. For this purpose, whilst making calculations using the S=7/2 Ising model and the Monte Carlo method, we made a specific heat measurement and a magnetization measurement of Gd-R alloy (R = Y, Zr) to compare experimental values and calculated ones. The results showed that the magnetic entropy change, specific heat, and Curie temperature can be estimated with good accuracy using the Monte Carlo method. (paper)

Influence of Sn incorporation on the properties of CuInS2 thin films grown by vacuum evaporation method

International Nuclear Information System (INIS)

Zribi, M.; Rabeh, M. Ben; Brini, R.; Kanzari, M.; Rezig, B.

2006-01-01

Structural, morphological and optical properties of Sn-doped CuInS 2 thin films grown by double source thermal evaporation method were studied. Firstly, the films were annealed in vacuum after evaporation from 250 to 500 deg. C for Sn deposition time equal to 3 min. Secondly, the films deposited for several Sn evaporation times were annealed in vacuum after evaporation at 500 deg. C. The X-ray diffraction spectra indicated that polycrystalline Sn-doped CuInS 2 films were obtained and no Sn binary or ternary phases are observed for the Sn evaporation times equal to 5 min. Scanning electron microscopy observation revealed the decrease of the surface crystallinity with increasing the Sn evaporation times and the annealing temperatures. The Sn-doped samples after annealing have bandgap energy of 1.42-1.50 eV. Furthermore, we found that the Sn-doped CuInS 2 thin films exhibit N-type conductivity after annealing

Electronic and structural properties of Sr2YSbO6

International Nuclear Information System (INIS)

Ortiz-Diaz, O.; Jairo Arbey Rodriguez, M.; Fajardo, F.; Landinez Tellez, D.A.; Roa-Rojas, J.

2007-01-01

The electronic and structural properties of the cubic perovskite Sr 2 YSbO 6 were predicted from ab initio calculations. Such properties were obtained using the density functional theory (DFT). The full-potential (linearized) augmented plane-wave ((L)APW) method was used, as it is implemented in wien2k code. We have optimized the volume of the unitary cell and the internal x parameter. The lattice constant (a) and x determine some length bonds. We have found that a=8.405 A, x=0.26177, and the bond lengths Y-O and Sb-O are 2.20 and 2.00 A, respectively. Additionally, Sr 2 YSbO 6 was prepared experimentally by the solid-state reaction method using stoichiometric mixtures of high purity (99.99%). By means of X-ray and Rietveld analysis, the main structural features were determined. The experimental lattice parameter is a=8.249 A, which differs about 1.9% of the value obtained using DFT. The bulk modulus is ∼133 GPa, which is not measured experimentally. DFT predicts that Sr 2 YSbO 6 is an indirect semiconductor and magnetic behavior does not have to be expected because at Fermi level the dominant orbitals are p-oxygen. The gap of the material is at least 2.5 eV

A novel method of rapidly modeling optical properties of actual photonic crystal fibres

International Nuclear Information System (INIS)

Li-Wen, Wang; Shu-Qin, Lou; Wei-Guo, Chen; Hong-Lei, Li

2010-01-01

The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties. Therefore, a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application. Up to now, the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments. To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly. In this paper, a novel method, based on the combination model of digital image processing and the finite element method, is proposed to rapidly model the optical properties of the actual photonic crystal fibre. Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled. It is confirmed from numerical results that the proposed method is simple, rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment. (rapid communication)

Crystal structure and magnetic properties of Tb6FeSb2

International Nuclear Information System (INIS)

Cai Gemei; Zhang Jiliang; He Wei; Qin Pingli; Zeng Lingmin

2006-01-01

The crystal structure and magnetic properties of Tb 6 FeSb 2 has been investigated for the first time. The compound crystallizes in the hexagonal, space group P6-bar 2m (No. 189) with the Ho 6 FeSb 2 structure type and lattice parameters a=8.1942(5)A, c=4.1758(3)A, z=1 and D calc =8.564g/cm 3 . Its magnetic properties were measured between 85 and 420K. The Curie temperature T c =256K was obtained using the method of intersecting tangents, and the effective paramagnetic moment was μ eff =9.32μ B per Tb atom

Enhanced thermoelectric properties of nano SiC dispersed Bi2Sr2Co2Oy Ceramics

Science.gov (United States)

Hu, Qiujun; Wang, Kunlun; Zhang, Yingjiu; Li, Xinjian; Song, Hongzhang

2018-04-01

The thermoelectric properties of Bi2Sr2Co2Oy + x wt% nano SiC (x = 0.00, 0.025, 0.05, 0.1, 0.2, and 0.3) prepared by the solid-state reaction method were investigated from 300 K to 923 K. The resistivity can be reduced effectively by adding a small amount of SiC nano particles, which is attributed to the increase of the carrier concentration. At the same time, the Seebeck coefficients can be improved effectively due to the energy filtering effect that low energy carriers are strongly dispersed at the interface between the SiC nano particles and the matrix. The decrease of thermal conductivity is due to the increase of the scattering ability of the phonons by the SiC nanoparticles distributed at the boundary of the matrix. As a result, the Bi2Sr2Co2Oy + x wt% SiC composites exhibit better thermoelectric properties. The maximum ZT value 0.24 is obtained when x = 0.05 at 923 K. Compared with the sample without SiC nano particles, the ZT value is increased by about 59.7%.

Proximal gamma-ray spectroscopy to predict soil properties using windows and full-spectrum analysis methods.

Science.gov (United States)

Mahmood, Hafiz Sultan; Hoogmoed, Willem B; van Henten, Eldert J

2013-11-27

Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0-15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0-15 cm soil depths than in the 15-30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method.

Substituent influence on the structural, vibrational and electronic properties of 2,5-dihydrothiophene-1,1-dioxide by experimental and DFT methods.

Science.gov (United States)

Arjunan, V; Thirunarayanan, S; Durga Devi, G; Mohan, S

2015-11-05

Spectroscopic and theoretical quantum chemical studies of 2,5-dihydrothiophene-1,1-dioxide and 3-methyl-2,5-dihydrothiophene-1,1-dioxide have been carried out by FTIR and FT-Raman spectral techniques along with B3LYP methods. The geometry of the compounds have been optimised by B3LYP method with 6-311++G(∗∗) and cc-pVTZ basis sets. The geometrical parameters obtained at B3LYP levels have been compared with the experimental values. Molecular electrostatic potential surface, total electron density distribution and frontier molecular orbital are constructed at B3LYP/cc-pVTZ level to understand the electronic properties. The charge density distribution and sites of chemical reactivity of the molecules have been obtained by mapping electron density isosurface with electrostatic potential surfaces. Natural bond orbital analysis of the molecules are carried out and the occupancies and the atomic hybrid contributions are calculated. Copyright © 2015 Elsevier B.V. All rights reserved.

Microstructure and Mechanical Properties of Al2O3/Er3Al5O12 Binary Eutectic Ceramic Prepared by Bridgman Method

Science.gov (United States)

Song, Caiyu; Wang, Shunheng; Liu, Juncheng; Zhai, Shuoyan

2018-01-01

Directionally solidified Al2O3/Er3Al5O12 (EAG) eutectic ceramic was prepared via vertical Bridgman method with high-frequency induction heating. The effects of the growth rate on the microstructure and mechanical properties of the solidified ceramic were investigated. The experimental results showed that there were no pores or amorphous phases in the directionally solidified Al2O3/EAG eutectic ceramic. Al2O3 phase was embedded in the EAG matrix phase, and the two phases were intertwined with each other to form a typical binary eutectic “hieroglyphic” structure. With the increase of growth rate, the phase size and spacing of the solidified Al2O3/EAG ceramic both decreased, and the growth rate and phase spacing satisfied the λ2v ≈ 60 formula of Jackson-Hunt theory. The cross section microstructure of the solidified ceramic always exhibited an irregular eutectic growth, while the longitudinal section microstructure presented a directional growth. The mechanical properties of the solidified ceramic gradually increased with the increase of growth rate, and the maximum hardness and fracture toughness could reach 21.57 GPa and 2.98 MPa·m1/2 respectively. It was considered that the crack deflection and branching could enhance the toughness of the solidified ceramic effectively. PMID:29601545

Statistical methods in epidemiology. VII. An overview of the chi2 test for 2 x 2 contingency table analysis.

Science.gov (United States)

Rigby, A S

2001-11-10

The odds ratio is an appropriate method of analysis for data in 2 x 2 contingency tables. However, other methods of analysis exist. One such method is based on the chi2 test of goodness-of-fit. Key players in the development of statistical theory include Pearson, Fisher and Yates. Data are presented in the form of 2 x 2 contingency tables and a method of analysis based on the chi2 test is introduced. There are many variations of the basic test statistic, one of which is the chi2 test with Yates' continuity correction. The usefulness (or not) of Yates' continuity correction is discussed. Problems of interpretation when the method is applied to k x m tables are highlighted. Some properties of the chi2 the test are illustrated by taking examples from the author's teaching experiences. Journal editors should be encouraged to give both observed and expected cell frequencies so that better information comes out of the chi2 test statistic.

Method for evaluation of radiative properties of glass samples

Energy Technology Data Exchange (ETDEWEB)

Mohelnikova, Jitka [Faculty of Civil Engineering, Brno University of Technology, Veveri 95, 602 00 Brno (Czech Republic)], E-mail: mohelnikova.j@fce.vutbr.cz

2008-04-15

The paper presents a simple calculation method which serves for an evaluation of radiative properties of window glasses. The method is based on a computer simulation model of the energy balance of a thermally insulated box with selected glass samples. A temperature profile of the air inside of the box with a glass sample exposed to affecting radiation was determined for defined boundary conditions. The spectral range of the radiation was considered in the interval between 280 and 2500 nm. This interval is adequate to the spectral range of solar radiation affecting windows in building facades. The air temperature rise within the box was determined in a response to the affecting radiation in the time between the beginning of the radiation exposition and the time of steady-state thermal conditions. The steady state temperature inside of the insulated box serves for the evaluation of the box energy balance and determination of the glass sample radiative properties. These properties are represented by glass characteristics as mean values of transmittance, reflectance and absorptance calculated for a defined spectral range. The data of the computer simulations were compared to experimental measurements on a real model of the insulated box. Results of both the calculations and measurements are in a good compliance. The method is recommended for preliminary evaluation of window glass radiative properties which serve as data for energy evaluation of buildings.

Thermal Shock Property of Al／Ni-ZrO2 Gradient Thermal Barrier Coatings

Institute of Scientific and Technical Information of China (English)

FANJin-juan; WANGQuan-sheng; ZHANGWei-fang

2004-01-01

Al/Ni-ZrO2 gradient thermal barrier coatings are made on aluminum substrate using plasma spraying method and one direction thermal shock properties of the coatings are studied in this paper. The results show that pores in coatings link to form cracks vertical to coating surface. They go through the whole ZrO2 coating once vertical cracks form. When thermal shock cycles increase, horizontal cracks that result in coatings failure forms in the coatings and interface. And vertical cracks delay appearance of horizontal cracks and enhance thermal shock property of coatings. Failure mechanisms of coating thermal shock are discussed using experiments and finite element method.

Dielectric, piezoelectric properties of MnO2-doped (K0.5Na0.5)NbO3–0.05LiNbO3 crystal grown by flux-Bridgman method

International Nuclear Information System (INIS)

Liu, Ying; Xu, Guisheng; Liu, Jinfeng; Yang, Danfeng; Chen, Xiaxia

2014-01-01

Highlights: • KNN–0.05LN based single crystals were grown by flux-Bridgman method. • Dielectric, piezoelecrc and ferroelectric properties were studied. • The effect of MnO 2 doping on the crystals' properties. • Dielectric and other properties were improved due to MnO 2 doping. - Abstract: Lead-free potassium sodium niobate piezoelectric single crystals substituted with lithium and then doped with MnO 2 (K 0.5 Na 0.5 )NbO 3 –0.05LiNbO 3 –yMnO 2 (y = 0%, 1.0% and 1.5%) (abbreviated as KNN–0.05LN–yMnO 2 ) have been grown by flux-Bridgman method using KCl–K 2 CO 3 eutectic composition as the flux. Their actual composition as well as the dielectric and piezoelectric properties were studied. Their actual composition deviated from the ratio of the raw materials due to different segregation coefficients of K and Na. The orthorhombic–tetragonal (T o–t ) and tetragonal–cubic phase transition temperature (the Curie temperature T c ) of the single crystal appears at 186 °C and 441 °C, respectively, for KNN–0.05LN–1.0%MnO 2 , shift to higher temperatures compared with that of pure KNN–0.05LN crystals, according to the dielectric permittivity versus temperature loops. The KNN–0.05LN–1.0%MnO 2 (001) plate shows higher piezoelectric coefficient d 33 and dielectric permittivity ε r when compared with pure KNN–0.05LN crystal, being on the order of 226 pC/N and 799 (161 pC/N and 530 for KNN–0.05LN), respectively. These excellent properties show that MnO 2 dopant is effective in improving KNN–0.05LN based piezoelectric crystals

Optimization of foaming properties of sludge protein solution by 60Co γ-ray/H2O2 using response surface methodology

International Nuclear Information System (INIS)

Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng; Zhang, Zhifang

2016-01-01

Response surface methodology and Box-Behnken experimental design were used to model and optimize the operational parameters of foaming properties of the sludge protein solution by 60 Co γ-ray/H 2 O 2 treatment. The four variables involved in this research were the protein solution concentration, H 2 O 2 , pH and dose. In the range studied, statistical analysis of the results showed that selected variables had a significant effect on protein foaming properties. The optimized conditions contained: protein solution concentration 26.50% (v/v), H 2 O 2 concentration 0.30% (v/v), pH value 9.0, and dose 4.81 kGy. Under optimal conditions, the foamability and foam stability approached 23.3 cm and 21.3 cm, respectively. Regression analysis with R 2 value of 0.9923 (foamability) and 0.9922 (foam stability) indicated a satisfactory correlation between the experimental data and predicted values (response). In addition, based on a feasibility analysis, the 60 Co γ-ray/H 2 O 2 method can improve odor and color of the protein foaming solution. - Highlights: • Effects of 60 Co γ-ray/H 2 O 2 on foaming properties of sludge protein were studied. • Response surface methodology and Box-Behnken experimental design were applied. • 60 Co γ-ray/H 2 O 2 method can improve foaming properties of protein solution.

A primer of statistical methods for correlating parameters and properties of electrospun poly( l -lactide) scaffolds for tissue engineering-PART 2: Regression

KAUST Repository

Seyedmahmoud, Rasoul; Mozetic, Pamela; Rainer, Alberto; Giannitelli, Sara Maria; Basoli, Francesco; Trombetta, Marcella; Traversa, Enrico; Licoccia, Silvia; Rinaldi, Antonio

2014-01-01

and interactions between a handful of key scaffold properties (Ys) and a set of process parameters (Xs) in electrospinning. While Part-1 dealt with the DOE methods to unveil the interactions between Xs in determining the morphomechanical properties (ref. Y1

Effect of Pb and Ag additions on electrical properties Bi2Sr2Ca2Cu3Ox superconductive ceramics

International Nuclear Information System (INIS)

Reddi, B.V.; Uskov, E.M.

1990-01-01

The influence of Pb and Ag additions on the electrical properties of Bi 2 Sr 2 Ca 2 Cu 3 O x superconducting ceramics has been studied by Hall method. It was found that the Pb additions has more influence on the sample characteristics than Ag. It was found, that Hall EMF at 77 K equal to zero in the samples having some residue resistance

Modified structural and magnetic properties of nanocrystalline MnFe{sub 2}O{sub 4} by pH in capping agent free co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Iranmanesh, P., E-mail: p.iranmanesh@vru.ac.ir [Department of Physics, Vali-e-Asr University of Rafsanjan, 77139-36417 Rafsanjan (Iran, Islamic Republic of); Saeednia, S. [Department of Chemistry, Vali-e-Asr University of Rafsanjan, 77139-36417 Rafsanjan (Iran, Islamic Republic of); Mehran, M.; Dafeh, S. Rashidi [Department of Physics, Vali-e-Asr University of Rafsanjan, 77139-36417 Rafsanjan (Iran, Islamic Republic of)

2017-03-01

Nano-sized manganese ferrite (MnFe{sub 2}O{sub 4}) particles were prepared using co-precipitation method in two different pH (9 and 11). The structural, morphological, optical and magnetic properties of as-synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis absorption and vibrating sample magnetometer (VSM). The FTIR spectra revealed two strong peaks at about 600 and 400 cm{sup −1} that can be attributed to the vibration mode of octahedral and tetrahedral sites of spinel structure of MnFe{sub 2}O{sub 4}, respectively. The XRD results showed that the nanocrystalline MnFe{sub 2}O{sub 4} has pure cubic spinel crystal structure with average crystallite size of 11 nm. The cation distribution of these nanoparticles was estimated by X-ray analysis data. The blue shift was observed in the band gap when compared with bulk sample which is due to the quantum size effect. The absence of hysteresis for MnFe{sub 2}O{sub 4} nanoparticles indicated the superparamagnetic behaviour, as expected for single domain nanoparticles. The obtained value for saturation magnetization being less than its value of bulk ones and larger pH is due to surface effects. The calculated magnetic particle size was smaller than crystallite size estimated from the XRD results; which indicate the presence of dead layer on particle surface. - Highlights: • We study effect of pH on the size and magnetic properties of MnFe{sub 2}O{sub 4} nanoparticles. • MnFe{sub 2}O{sub 4} were synthesized by co-precipitation method without any capping agent. • The physical properties are affected by cation contribution and surface effects. • The smaller nanoparticles with larger pH show a red shift in the band gap energy. • The M{sub s} is less than its value of bulk ones due to surface effects.

Semiempirical Quantum-Chemical Orthogonalization-Corrected Methods: Benchmarks for Ground-State Properties.

Science.gov (United States)

Dral, Pavlo O; Wu, Xin; Spörkel, Lasse; Koslowski, Axel; Thiel, Walter

2016-03-08

The semiempirical orthogonalization-corrected OMx methods (OM1, OM2, and OM3) go beyond the standard MNDO model by including additional interactions in the electronic structure calculation. When augmented with empirical dispersion corrections, the resulting OMx-Dn approaches offer a fast and robust treatment of noncovalent interactions. Here we evaluate the performance of the OMx and OMx-Dn methods for a variety of ground-state properties using a large and diverse collection of benchmark sets from the literature, with a total of 13035 original and derived reference data. Extensive comparisons are made with the results from established semiempirical methods (MNDO, AM1, PM3, PM6, and PM7) that also use the NDDO (neglect of diatomic differential overlap) integral approximation. Statistical evaluations show that the OMx and OMx-Dn methods outperform the other methods for most of the benchmark sets.

Magnetic properties of iron-based soft magnetic composites with SiO{sub 2} coating obtained by reverse microemulsion method

Energy Technology Data Exchange (ETDEWEB)

Wu, Shen [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Sun, Aizhi, E-mail: sunaizhi@126.com [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Lu, Zhenwen; Cheng, Chuan [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Gao, Xuexu [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

2015-05-01

In this work, iron-based soft magnetic composites coated with the amorphous SiO{sub 2} layer have been fabricated by utilizing tetraethoxysilane in the reverse microemulsion method, and then the effects of addition amount of SiO{sub 2} and annealing temperature on the magnetic properties were investigated. The results show that the surface of iron powders contains a thin amorphous SiO{sub 2} insulation layer, which effectively decreases the magnetic loss of synthesized magnets. The magnetic loss of coated samples decreased by 87.8% as compared with that of uncoated samples at 150 kHz. Magnetic measurements show that the sample with 1.25 wt% SiO{sub 2} has an acceptable real part and minimum imaginary part of permeability in comparison with other samples. Also, the annealing treatment increased the initial permeability, the maximum permeability and the magnetic induction and decreased the coercivity with increasing temperature in the range 300–600 °C. The results of the loss separation imply that the annealed SMCs have a higher hysteresis loss coefficient (k{sub 2}) and lower eddy current loss coefficient (k{sub 3}) as compared with the pure iron compacts after the same heat treatment due to the preservation of the SiO{sub 2} layer. - Highlights: • SiO{sub 2} coated the iron powder by reverse microemulsion method, decreased the magnetic loss of SMCs. • 25 wt% is the optimum coating amount to attain the desired permeability. • The influence of annealing temperature on the magnetic performance of the core was discussed. • Compare with the pure iron compacts, the annealed SMCs have lower value of eddy current coefficient.

Structural, electronic and magnetic properties of LaCr2Si2C: Ab initio calculation, mean field approximation and Monte-Carlo simulation

Science.gov (United States)

Endichi, A.; Zaari, H.; Benyoussef, A.; El Kenz, A.

2018-06-01

The magnetic behavior of LaCr2Si2C compound is investigated in this work, using first principle methods, Monte Carlo simulation (MCS) and mean field approximation (MFA). The structural, electronic and magnetic properties are described using ab initio method in the framework of the Generalized Gradient Approximation (GGA), and the Full Potential-Linearized Augmented Plane Wave (FP-LAPW) method implemented in the WIEN2K packages. We have also computed the coupling terms between magnetic atoms which are used in Hamiltonian model. A theoretical study realized by mean field approximation and Monte Carlo Simulation within the Ising model is used to more understand the magnetic properties of this compound. Thereby, our results showed a ferromagnetic ordering of the Cr magnetic moments below the Curie temperature of 30 K (Tc magnetization, the energy, the specific heat and the susceptibility. This material shows the small sign of supra-conductivity; and future researches could be focused to enhance the transport and magnetic properties of this system.

Vapor pressures, thermodynamic stability, and fluorescence properties of three 2,6-alkyl naphthalenes.

Science.gov (United States)

Santos, Ana Filipa L O M; Oliveira, Juliana A S A; Ribeiro da Silva, Maria D M C; Monte, Manuel J S

2016-03-01

This work reports the experimental determination of relevant thermodynamic properties and the characterization of luminescence properties of the following polycyclic aromatic hydrocarbons (PAHs): 2,6-diethylnaphthalene, 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene. The standard (p(o) = 0.1 MPa) molar enthalpies of combustion, ΔcHm(o), of the three compounds were determined using static bomb combustion calorimetry. The vapor pressures of the crystalline phase of 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene were measured at different temperatures using the Knudsen effusion method and the vapor pressures of both liquid and crystalline phases of 2,6-diethylnaphthalene were measured by means of a static method. The temperatures and the molar enthalpies of fusion of the three compounds were determined using differential scanning calorimetry. The gas-phase molar heat capacities and absolute entropies of the three 2,6-dialkylnaphthalenes studied were determined computationally. The thermodynamic stability of the compounds in both the crystalline and gaseous phases was evaluated by the determination of the Gibbs energies of formation and compared with the ones reported in the literature for 2,6-dimethylnaphthalene. From fluorescence spectroscopy measurements, the optical properties of the compounds studied and of naphthalene were evaluated in solution and in the solid state. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of artificial intelligence methods for prediction of steel mechanical properties

Directory of Open Access Journals (Sweden)

Z. Jančíková

2008-10-01

Full Text Available The target of the contribution is to outline possibilities of applying artificial neural networks for the prediction of mechanical steel properties after heat treatment and to judge their perspective use in this field. The achieved models enable the prediction of final mechanical material properties on the basis of decisive parameters influencing these properties. By applying artificial intelligence methods in combination with mathematic-physical analysis methods it will be possible to create facilities for designing a system of the continuous rationalization of existing and also newly developing industrial technologies.

Synthesis, surface properties and photocatalytic abilities of semiconductor In{sub 2}Cu{sub 2}O{sub 5} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Xu, Jian; Wan, Yingpeng; Huang, Yanlin [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Wang, Yaorong, E-mail: yrwang@suda.edu.cn [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Lin [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2016-12-15

Highlights: • In{sub 2}Cu{sub 2}O{sub 5} has high absorption in the UV-green and red wavelength region. • The nanoparticles present efficient photocatalytsis under visible light. • The photochemical properties were elucidated on its structure properties. - Abstract: In{sub 2}Cu{sub 2}O{sub 5} photocatalyst was prepared by the sol-gel method which produced worm-like nanoparticles. The X-ray powder diffraction (XRD) measurement and Rietveld structural refinement were applied to elucidate the phase formation and structural properties. The morphological properties of the surfaces were measured by scanning electron microscope (SEM), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). The nanoparticles present optical absorption from both the host lattices and the d–d transitions of distorted Cu{sup 2+} octahedra in UV–vis light wavelength region. The band-gap of In{sub 2}Cu{sub 2}O{sub 5} photocatalyst is about 2.31 eV. The photocatalytic abilities of In{sub 2}Cu{sub 2}O{sub 5} nanoparticles were verified by photo-degradation of methylene blue (MB) solutions irradiated by visible light. The energy potential and bad structure were discussed. In{sub 2}Cu{sub 2}O{sub 5} nanoparticles have the potential application for the efficient photocatalysis on MB dye solutions.

Thermodynamic properties of 5(nitrophenyl) furan-2-carbaldehyde isomers.

Science.gov (United States)

Dibrivnyi, Volodymyr; Sobechko, Iryna; Puniak, Marian; Horak, Yuriy; Obushak, Mykola; Van-Chin-Syan, Yuriy; Andriy, Marshalek; Velychkivska, Nadiia

2015-01-01

The aim of the current work was to determine thermo dynamical properties of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde. The temperature dependence of saturated vapor pressure of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde was determined by Knudsen's effusion method. The results are presented by the Clapeyron-Clausius equation in linear form, and via this form, the standard enthalpies, entropies and Gibbs energies of sublimation and evaporation of compounds were calculated at 298.15 K. The standard molar formation enthalpies of compounds in crystalline state at 298.15 K were determined indirectly by the corresponding standard molar combustion enthalpy, obtained using bomb calorimetry combustion. Determination of the thermodynamic properties for these compounds may contribute to solving practical problems pertaining optimization processes of their synthesis, purification and application and it will also provide a more thorough insight regarding the theoretical knowledge of their nature.Graphical abstract:Generalized structural formula of investigated compounds and their formation enthalpy determination scheme in the gaseous state.

Effect of mucin extraction method on some properties of ...

African Journals Online (AJOL)

Effect of mucin extraction method on some properties of metronidazole mucoadhesive loaded patches. MI Arhewoh, SO Eraga, PF Builders, MA Ibobiri. Abstract. To evaluate the effects of mucin extraction method and plasticizer concentration on the bioadhesive strength and metronidazole release profile from mucin-based ...

Properties and solution methods for large location-allocation problems

DEFF Research Database (Denmark)

Juel, Henrik; Love, Robert F.

1982-01-01

Location-allocation with l$ _p$ distances is studied. It is shown that this structure can be expressed as a concave minimization programming problem. Since concave minimization algorithms are not yet well developed, five solution methods are developed which utilize the special properties of the l......Location-allocation with l$ _p$ distances is studied. It is shown that this structure can be expressed as a concave minimization programming problem. Since concave minimization algorithms are not yet well developed, five solution methods are developed which utilize the special properties...... of the location-allocation problem. Using the rectilinear distance measure, two of these algorithms achieved optimal solutions in all 102 test problems for which solutions were known. The algorithms can be applied to much larger problems than any existing exact methods....

Synthesis and physical-chemical properties of 3-alkylthio-5-(quinoline-2-yl, 2-hydroxyquinoline-4-yl-4-R-2,4-dihydro-3H-1,2,4-triazoles

Directory of Open Access Journals (Sweden)

T. M. Kaplaushenko

2016-06-01

Full Text Available The major social and economic problem of pharmaceutical industry is the search for biologically active substances, which may become the basis of new drugs, competitive with expensive imported drugs. Analysis of literature shows that in recent decades the attention is paid to researches of heterocyclic systems as potential biologically active agents of both domestic and foreign scientists. Particular interest in this regard cause 3-thio derivatives of 1,2,4-triazoles. Despite high number of publications relating to synthesis and biological properties of 1,2,4-triazole derivatives, the structure and physical-chemical properties of these compounds are studied insufficiently. In this regard, the study of synthetic, physical-chemical and biological properties of 3-alkylthio-5-(quinoline-2-yl, 2-hydroxyquinoline-4-yl-4-R1-2,4-dihydro-3H-1,2,4-triazoles in our point of view is a new, theoretically and practically significant direction. Purpose - targeted synthesis of new low-toxic and highly effective compounds with potential pharmacological activity in a series of 3-alkylthio-5-(quinoline-2-yl, 2-hydroxyquinoline-4-yl-4-R-2,4-dihydro-3H-1,2,4-triazoles and the study of physical and chemical properties of the synthesized compounds. Materials and methods. As starting compounds 5-(quinoline-2-il- 2-hydroxyquinoline-4-yl-4-R1-3-thio-1,2,4-triazoles have been used. Through further cooperation with halogen alkanes (ethyl bromide, propyl bromide, amyl bromide, octyl bromide, nonyl bromide, decyl bromide, cyclohexyl chloride, benzyl chloride 3-alkylthio-5-(quinoline-2-yl, 2-hydroxyquinoline-4-yl-4-R1-2,4-dyhidro-3H-1,2,4-triazoles have been obtained. Results. 15 New compounds have been received as a result of synthetic transformations, the structure of synthesized compounds has been confirmed by modern complex of physical and chemical methods of analysis (IR-spectrophotometry, 1H NMR-spectroscopy, elemental analysis, and their individuality has been proved by

Thermal properties and kinetics of Al/α-MnO{sub 2} nanostructure thermite

Energy Technology Data Exchange (ETDEWEB)

Song, Jia-Xing; Fang, Xiang; Guo, Tao; Ding, Wen; Zhang, Xiao-Nan; Yao, Miao, E-mail: 1023855857@qq.com [PLA University of Science and Technology, Nanjing (China); Bei, Feng-Li; Yu, Hong-Jun [Nanjing University of Science and Technology (China)

2018-05-01

In this work, thermal properties and kinetics of Al-nanoparticles/α-MnO{sub 2} nanorods thermite were reported. The α-MnO{sub 2} nanorods were synthesized using a hydrothermal method and were characterized by X-ray powder diffraction (XRD) and X-ray photoelectron spectra (XPS), then combined with Al nanoparticles based on the ultrasonic mixing method to prepare the nanostructure thermite. Besides, both pure components and mixture were characterized by field emission scanning electron microscopy (FE-SEM) to observe their morphologies and structures. Subsequently, the thermal properties of Al/α-MnO{sub 2} nanostructure thermite were studied on the basis of thermogravimetric-differential scanning calorimetry (TG-DSC). According to the TG-DSC tests, the calculation results of activation energy for kinetics of Al/α-MnO{sub 2} thermite were obtained using different isoconversional methods. It was found that Al/α-MnO{sub 2} nanostructure thermite has high heat release and low onset temperature, and the heat release of the nanostructure thermite was approximately 1146.6 J g{sup -1}. (author)

Fracture properties of ThO2-UO2 pellets by Hertzian indentation technique

International Nuclear Information System (INIS)

Kutty, T.R.G.; Rath, B.N.; Balakrishnan, K.S.

2005-01-01

Fracture toughness (K Ic ) and fracture surface energy (γ s ) of ThO 2 -UO 2 pellets with varying UO 2 contents were measured using Hertzian indentation technique. The knowledge of fracture toughness (K Ic ) and fracture surface energy values are important for fuel designers since these values are used in fuel modeling. Cracks in nuclear fuel act as a path for fission gas release and enhances fuel cladding mechanical interaction. Microstructural features like grain size and presence of second phase play a significant role in controlling the fracture behavior. Since the fracture properties of nuclear materials are of primary design consideration, it is important that these properties should be evaluated with good precision. There have been several attempts to use Hertzian indentation for evaluating the fracture toughness of brittle materials. The main principle of this method depends on the interaction of the elastic stress field with a pre-existing surface flaw of the sample. One significant advantage of Hertzian indentation over that of Vickers is that the substrate's deformation is entirely elastic until fracture occurs. This avoids the complications arising from the ill-defined residual stress that is normally associated with indentations brought about by pointed indenters like that of Vickers. The material properties that may be determined by this test include (a) fracture toughness and fracture surface energy of the near surface material, (b) the densities and sizes of surface cracks, and (c) residual stresses in the near surface material. This paper deals with experimental procedure for the evaluation of fracture properties of ThO 2 -UO 2 of varying U content and results thus obtained are also presented. The K Ic values thus obtained are explained in terms of their microstructures and the U content. (author)

A new method of application of hydrated salts on textiles to achieve thermoregulating properties

International Nuclear Information System (INIS)

Kazemi, Zeinab; Mortazavi, Sayed Majid

2014-01-01

Graphical abstract: - Highlights: • No need to microencapsulate the salt. • New method Glauber's salt dehydration. • Supercooling decreased, heat storage increased. - Abstract: Recently there has been a lot of attention to fibers and fabrics with thermoregulatory effects. We can acquire this quality using Phase Change Materials (PCM). In this investigation a simple method was used to keep Na 2 SO 4 ·10H 2 O as an inorganic PCM on textile structure. By this method it is not necessary for PCMs to be microencapsulated. Thermophysical properties and thermal stability effects of treated fabric was checked out by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometry (XRD) analysis were used to study the chemical structure of the fabric with PCMs. The air transfer, water permeability, and some physical properties of treated fabric were also investigated. The results showed that, silicone rubber polymer could be applied on textile structure to hold PCM without microencapsulating, and treated textile can be served as an appropriate smart thermal insulator

A new method of application of hydrated salts on textiles to achieve thermoregulating properties

Energy Technology Data Exchange (ETDEWEB)

Kazemi, Zeinab; Mortazavi, Sayed Majid, E-mail: mortaza@cc.iut.ac.ir

2014-08-10

Graphical abstract: - Highlights: • No need to microencapsulate the salt. • New method Glauber's salt dehydration. • Supercooling decreased, heat storage increased. - Abstract: Recently there has been a lot of attention to fibers and fabrics with thermoregulatory effects. We can acquire this quality using Phase Change Materials (PCM). In this investigation a simple method was used to keep Na{sub 2}SO{sub 4}·10H{sub 2}O as an inorganic PCM on textile structure. By this method it is not necessary for PCMs to be microencapsulated. Thermophysical properties and thermal stability effects of treated fabric was checked out by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometry (XRD) analysis were used to study the chemical structure of the fabric with PCMs. The air transfer, water permeability, and some physical properties of treated fabric were also investigated. The results showed that, silicone rubber polymer could be applied on textile structure to hold PCM without microencapsulating, and treated textile can be served as an appropriate smart thermal insulator.

Standard Test Methods for Properties of Continuous Filament Carbon and Graphite Fiber Tows

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 These test methods cover the preparation and tensile testing of resin-impregnated and consolidated test specimens made from continuous filament carbon and graphite yarns, rovings, and tows to determine their tensile properties. 1.2 These test methods also cover the determination of the density and mass per unit length of the yarn, roving, or tow to provide supplementary data for tensile property calculation. 1.3 These test methods include a procedure for sizing removal to provide the preferred desized fiber samples for density measurement. This procedure may also be used to determine the weight percent sizing. 1.4 These test methods include a procedure for determining the weight percent moisture adsorption of carbon or graphite fiber. 1.5 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of t...

Semi-convergence properties of Kaczmarz’s method

DEFF Research Database (Denmark)

Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

2014-01-01

Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges......-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging....

In situ thermal properties characterization using frequential methods

Energy Technology Data Exchange (ETDEWEB)

Carpentier, O.; Defer, D.; Antczak, E.; Chauchois, A.; Duthoit, B. [Laboratoire dArtois de Mecanique Thermique Instrumentation (LAMTI), FSA Universite dArtois, Technoparc Futura, 62400 Bethune (France)

2008-07-01

In numerous fields, especially that of geothermal energy, we need to know about the thermal behaviour of the soil now that the monitoring of renewable forms of energy is an ecological, economic and scientific issue. Thus heat from the soil is widely used for air-conditioning systems in buildings both in Canada and in the Scandinavian countries, and it is spreading. The effectiveness of this technique is based on the soils calorific potential and its thermophysical properties which will define the quality of the exchanges between the soil and a heat transfer fluid. This article puts forward a method to be used for the in situ thermophysical characterisation of a soil. It is based upon measuring the heat exchanges on the surface of the soil and on measuring a temperature a few centimetres below the surface. The system is light, inexpensive, well-suited to the taking of measurements in situ without the sensors used introducing any disturbance into the heat exchanges. Whereas the majority of methods require excitation, the one presented here is passive and exploits natural signals. Based upon a few hours of recording, the natural signals allow us to identify the soils thermophysical properties continuously. The identification is based upon frequency methods the quality of which can be seen when the thermophysical properties are injected into a model with finite elements by means of a comparison of the temperatures modelled and those actually measured on site. (author)

Synthesis, physical-chemical properties of 2-((4-R-5-(thiophene-2-ylmethyl-4H-1,2,4-triazole-3-ylthioacetohydrazides

Directory of Open Access Journals (Sweden)

O. A. Suhak

2017-04-01

Full Text Available Aim. Analysis of the scientific literature over the past decade has shown that large synthetic possibilities towards creating new and effective drug substances have heterocyclic compounds, in particular the derivatives of 1,2,4-triazole. 1,2,4-Triazole is a structural fragment of many synthetic drugs. The special interest cause ylidene hydrazides of 2-(5-R-1,2,4-triazole-3-ylthioacetic acids as potential biologically active compounds, among which highly effective medicines can be found. With the aim of finding new biologically active compounds the derivatives of 2-((4-R-5-(thiophene-2-ylmethyl-4H-1,2,4-triazole-3-ylthioaceticohydrazides have been synthesized, their physical-chemical properties have been studied with the use of modern methods, namely elemental analysis, IR,1H-NMR spectroscopy, and their individuality by HPLC-MS. Materials and methods. N'-R1-еden-2-((4-R-5-(thiophene-2-ylmethyl-4H-1,2,4-triazole-3-ylthioaceticohydrazides were received by adding aromatic (2-BrC6H4, 2,3-(OCH32C6H3, 3,5-(OCH32C6H3, 4-N(CH32C6H4, 3,4-F2C6H3, 2-NO2C6H4,4-NO2C6H4, 4-OHC6H4, 2-OHC6H4, 4-FC6H4, 2-CI-6-FC6H3 or heterocyclic (2-SC4H3, 5-NO2-2-C4H2O aldehyde to an equivalent amount of the appropriate 2-((4-R-5-(thiophene-2-ylmethyl-4H-1,2,4-triazole-3-ylthioaceticohydrazide in the acetic acid medium. The study of physical-chemical properties of obtained compounds was carried out according to the methods outlined in SPU. Chromato-mass-spectral studies were performed on hazarding chromatograph Agilent 1260 Infinity HPLC equipped with mass spectrometer Agilent 6120 with ionization in electro-spray (ESI. Conclusion. This suggests the possibility for further study of biological action of the synthesized compounds. As a result of studies the N'-R1-eden-2-((4-R-5-(thiophene-2-ylmethyl-4H-1,2,4-triazole-3-ylthioaceticohydrazides have been synthesized and their physical-chemical properties have been studied.

The effect of Cu{sup 2+} on structure, morphology and optical properties of flower-like ZnO synthesized using the chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Koao, L.F., E-mail: koaolf@qwa.ufs.ac.za [Department of Physics, University of the Free State, Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, B.F. [Department of Physics, University of the Free State, Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300 (South Africa)

2014-04-15

In this work undoped and Cu{sup 2+}-doped ZnO nanostructures were prepared by the chemical bath deposition (CBD) method at 80 °C. The structural, optical and luminescence properties of the undoped and Cu{sup 2+}-doped ZnO nanostructures were determined by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV–Visible Spectroscopy (UV) and Photoluminescence spectroscopy (PL) analyses. XRD analysis showed the sample prepared were hexagonal ZnO with grain sizes in the order of 46±1 nm. The estimated grain size was found not to dependent on the concentration of the Cu{sup 2+} ions used. The SEM analysis revealed that the shapes of the particles were flower-like and the addition of Cu{sup 2+} ions influenced the morphology of the samples. In the UV–Visible study the reflectance intensity decreased with an increase in the molar concentration of Cu{sup 2+} and there was no shift in the absorption edges. The PL analyses revealed that the highest luminescence intensity was obtained for the undoped ZnO. Thus Cu incorporated into the ZnO resulted in the change in its morphological, structural, and optical and luminescence properties.

Method for Non-Invasive Determination of Chemical Properties of Aqueous Solutions

Science.gov (United States)

Todd, Paul W. (Inventor); Jones, Alan (Inventor); Thomas, Nathan A. (Inventor)

2016-01-01

A method for non-invasively determining a chemical property of an aqueous solution is provided. The method provides the steps of providing a colored solute having a light absorbance spectrum and transmitting light through the colored solute at two different wavelengths. The method further provides the steps of measuring light absorbance of the colored solute at the two different transmitted light wavelengths, and comparing the light absorbance of the colored solute at the two different wavelengths to determine a chemical property of an aqueous solution.

Metformin: A Review of Characteristics, Properties, Analytical Methods and Impact in the Green Chemistry.

Science.gov (United States)

da Trindade, Mariana Teixeira; Kogawa, Ana Carolina; Salgado, Hérida Regina Nunes

2018-01-02

Diabetes mellitus (DM) is considered a public health problem. The initial treatment consists of improving the lifestyle and making changes in the diet. When these changes are not enough, the use of medication becomes necessary. The metformin aims to reduce the hepatic production of glucose and is the preferred treatment for type 2. The objective is to survey the characteristics and properties of metformin, as well as hold a discussion on the existing analytical methods to green chemistry and their impacts for both the operator and the environment. For the survey, data searches were conducted by scientific papers in the literature as well as in official compendium. The characteristics and properties are shown, also, methods using liquid chromatography techniques, titration, absorption spectrophotometry in the ultraviolet and the infrared region. Most of the methods presented are not green chemistry oriented. It is necessary the awareness of everyone involved in the optimization of the methods applied through the implementation of green chemistry to determine the metformin.

OPTOELECTRONIC PROPERTIES OF CdS – AgInS2 SOLAR CELLS

Directory of Open Access Journals (Sweden)

M. A. Abdullaev

2016-01-01

Full Text Available Aim. To conduct experimental studies of optoelectronic properties of CdS - AgInS2 solar cells.Methods. AgInS2 films for solar cell CdS-AgInS2 were obtained by magnetron sputtering of crystalline targets derived from bulk ingots. Cadmium sulfide layers were deposited on the AgInS2 films by an electrochemical method in cadmium salts solution, thiourea and ammonia. AgInS2 bulk crystals were obtained in two stages: a direct fusion of the primary components (99,999 in a stoichiometric ratio, followed by directional solidification in a vertical furnace; re-synthesis has been performed on a staggered basis by heating the obtained ingots at temperatures close to the melting points of elements in the two-zone horizontal furnace.Findings. The paper presents the results of experimental studies of the electrical properties and photosensitivity of CdS-AgInS2 film heterojunction obtained by the magnetron. We measured the current-voltage characteristics and quantum efficiency of photoconversion at temperatures up to 250-356 K. We also identified the short circuit current of up to 25 mA/cm2 and open circuit voltage of 0.38 V.Conclusions. The study of the properties of solar cells in recent years has an important place. The results presented in the work would contribute to more efficient conversion of solar energy into electricity.

Thermal transport properties of MoS ₂ and MoSe ₂ monolayers

Energy Technology Data Exchange (ETDEWEB)

Kandemir, Ali; Yapicioglu, Haluk; Kinaci, Alper; Çağın, Tahir; Sevik, Cem

2016-01-11

Isolation of single to few layer transition metal dichalgogenides open alternate venues in application of 2 dimensional materials to nanoelectronics. Either for general overheating issues or specific application in thermoelectric devices, the characterization of the thermal transport in these new low dimensional materials is needed for their efficient implementation. In this study, lattice thermal conductivities of single layer MoS₂ and MoSe₂ are evaluated using classical molecular dynamics method. The interactions between atoms are defined by Stillinger-Weber type empirical potentials that are developed to represent structural, mechanical, and vibrational properties of the given materials. In parameterization of the potentials, a stochastic optimization algorithm, namely particle swarm optimization is utilized. The final parameter sets produce quite consistent results with DFT in terms of lattice parameters, bond distances, elastic constants and vibrational properties of both single layer MoS₂ and MoSe₂. The predicted thermal properties of both materials are in very good agreement with earlier first principles calculations. The discrepancies between calculations and experimental measurements are most likely to be caused by pristine nature of the structures in our simulations.

Theoretical and experimental methods to determine the properties of molten core components and reaction products. Pt. 2

International Nuclear Information System (INIS)

Nazare, S.; Ondracek, G.; Schulz, B.

1975-10-01

In the course of a loss of coolant accident, a sequence of events would be initiated that ultimately could lead to core melting. The course of these events and the consequences of core meltdown would in part be determined by the properties of the core materials and the products of their interaction. On the basis of available theoretical and experimental results, the report attempts an estimation of properties such as: 1) work of adhesion between UO 2 - and (U,Zr) liquid phase, 2) heat of fusion of some melts, 3) heat capacity of liquid reaction products, 4) viscosity of liquid reaction products, 5) thermal conductivity of liquid reaction products. Experimental work is suggested for those cases, where the estimates need to be improved or verified. (orig.) [de

Morphological, structural and magnetic properties of α-Fe2O3 nanoparticles in an amorphous alumina matrix obtained by aqueous combustion method

International Nuclear Information System (INIS)

Tadic, Marin; Kusigerski, Vladan; Markovic, Dragana; Citakovic, Nada; Remskar, Maja; Spasojevic, Vojislav

2009-01-01

We report on morphological, structural and magnetic properties of α-Fe 2 O 3 nanoparticles in an amorphous alumina matrix synthesized by aqueous combustion method. The sample was characterized by X-ray powder diffraction (XRPD), high-resolution electron microscopy (HREM) and SQUID magnetometry. XRPD study reveals the phase purity of α-Fe 2 O 3 whereas HREM images show an unusual spongy structure and well-crystallized nanoparticles with a size of about 25 nm. Magnetic measurements show a high irreversibility temperature T irr ∼ 350 K, Morin transition at T M ∼ 210 K, increase of the magnetization below T ∼ 45 K and hysteretic behavior below T M at 5 K and 200 K.

Sandwich Structured Composites for Aeronautics: Methods of Manufacturing Affecting Some Mechanical Properties

Directory of Open Access Journals (Sweden)

Aneta Krzyżak

2016-01-01

Full Text Available Sandwich panels are composites which consist of two thin laminate outer skins and lightweight (e.g., honeycomb thick core structure. Owing to the core structure, such composites are distinguished by stiffness. Despite the thickness of the core, sandwich composites are light and have a relatively high flexural strength. These composites have a spatial structure, which affects good thermal insulator properties. Sandwich panels are used in aeronautics, road vehicles, ships, and civil engineering. The mechanical properties of these composites are directly dependent on the properties of sandwich components and method of manufacturing. The paper presents some aspects of technology and its influence on mechanical properties of sandwich structure polymer composites. The sandwiches described in the paper were made by three different methods: hand lay-up, press method, and autoclave use. The samples of sandwiches were tested for failure caused by impact load. Sandwiches prepared in the same way were used for structural analysis of adhesive layer between panels and core. The results of research showed that the method of manufacturing, more precisely the pressure while forming sandwich panels, influences some mechanical properties of sandwich structured polymer composites such as flexural strength, impact strength, and compressive strength.

Comparative studies on structural properties and antimicrobial potential of spinel ferrite nanoparticles synthesized using various methods

Science.gov (United States)

Baraliya, Jagdish D.; Rakhashiya, Purvi M.; Patel, Pooja P.; Thaker, Vrinda S.; Joshi, Hiren H.

2017-05-01

In this study, novel multifunctional magnetic iron-based nanoparticles (CoFe2O4) coated with silica, silica-DEG (diethylene glycol), PEG (polyethylene glycol) were synthesized using Auto Combustion Method (ACM), Co-precipitation Method (COPM), Citrate Precursor Method (CPM), Flash Combustion Method (FCM). These spinel ferrite nanoparticles also contain very high antibacterial properties to fulfill the requirements of a drug delivery system so that the antibiotic concentration could be minimized. A potential delivery system could be based on a ferromagnetic fluid. The effects of various preparation methods on the physical properties of the nanoparticles were examined. The nanoparticles were also tested against four human pathogenic bacteria (Gram negative E.coli, P. aeruginosa, Gram positive S. aureus, S. pyogenus) and two fungi (C. albicans, A.niger). It was revealed that a nanoparticle has strong antibacterial activity as compared to antifungal. Further, Gram positive bacteria are more affected than Gram negative bacteria. It was also clear that different methods of coating have great influence on the antimicrobial properties. It was observed that these nanoparticles have significantly different but potentially very high antimicrobial activities against the tested organisms than found elsewhere by other nanoparticles on the same organisms.

Structure and properties of TeO2-WO3 system glasses

International Nuclear Information System (INIS)

Kolobkov, V.P.; Ovcharenko, N.V.; Morozova, I.N.; Chebotarev, S.A.; Chikovskij, A.N.; Arkatova, T.G.

1987-01-01

Study of TeO 2 -WO 3 system is of interest for production of high-refractive-glasses with comparatively low crystallizability. Results of investigating some properties and structural features of this system glasses are presented. Composition and properties of studied glasses are presented. The properties were studied using the following techniques: the density was measured by hydrostatic weighing in toluene; thermal expansion coefficient was measured in quartz dilatometer DKV-5A; dilatometric temperature of glass softening (T g ) was defined as an intersection point of linear and curved parts of the plot of thermal expansion coefficient; refractive index (RI) - by immersion method; dielectric properties are measured. Consideration of vibronic spectra permits to conclude that in tungsten-tellurium glasses rare earth activator ions are arranged near tellurite and tungstate groupings proportional to glass-forming component content

Structure–property relationships of iron–hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method

Energy Technology Data Exchange (ETDEWEB)

Nordin, Jamillah Amer [Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Prajitno, Djoko Hadi [Nuclear Technology Center for Materials and Radiometry, National Nuclear Energy, Bandung 40132 (Indonesia); Saidin, Syafiqah [Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Nur, Hadi, E-mail: hadi@kimia.fs.utm.my [Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Department of Physics, Institut Sains dan Teknologi Nasional, Jl. Moh. Kahfi II, Jagakarsa, Jakarta Selatan 12640 (Indonesia); Hermawan, Hendra, E-mail: hendra.hermawan@gmn.ulaval.ca [Department of Mining, Metallurgical and Materials Engineering & CHU de Québec Research Center, Laval University, Québec City G1V 0A6 (Canada)

2015-06-01

Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone–implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12 h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12 h milling in the presence of HPO{sub 4}{sup 2−} ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12 h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesis - Highlights: • Improvement of mechanical properties of HAp bioceramics by mechanosynthesis method • Structure–property relationship of iron–hydroxyapatite ceramic matrix nanocomposite • Milling time influenced the properties of iron–hydroxyapatite ceramic matrix nanocomposite.

Structure–property relationships of iron–hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method

International Nuclear Information System (INIS)

Nordin, Jamillah Amer; Prajitno, Djoko Hadi; Saidin, Syafiqah; Nur, Hadi; Hermawan, Hendra

2015-01-01

Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone–implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12 h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12 h milling in the presence of HPO 4 2− ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12 h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesis - Highlights: • Improvement of mechanical properties of HAp bioceramics by mechanosynthesis method • Structure–property relationship of iron–hydroxyapatite ceramic matrix nanocomposite • Milling time influenced the properties of iron–hydroxyapatite ceramic matrix nanocomposite

Preparation of Pr-doped SnO{sub 2} hollow nanofibers by electrospinning method and their gas sensing properties

Energy Technology Data Exchange (ETDEWEB)

Li, W.Q.; Ma, S.Y., E-mail: lwq19891013@126.com; Li, Y.F.; Li, X.B.; Wang, C.Y.; Yang, X.H.; Cheng, L.; Mao, Y.Z.; Luo, J.; Gengzang, D.J.; Wan, G.X.; Xu, X.L.

2014-08-25

Highlights: • Pr-doped SnO{sub 2} hollow nanofibers were fabricated by electrospinning. • The crystal structures, surface morphology, chemical state and gas sensing performance were investigated. • The Pr-doped SnO{sub 2} hollow structure exhibited good gas-sensing properties to ethanol at 300 °C. • The relationships between response time (recovery time) and temperature, response time (recovery time) and concentration were investigated. • A sensor mechanism of hollow nanofibers depend on temperature was discussed. - Abstract: Pure and Pr-doped SnO{sub 2} hollow nanofibers were fabricated through a facile single capillary electrospinning and followed by calcination. The properties of as-synthesized nanofibers were characterized by scanning electron microscopy, Brunauer–Emmett–Teller, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Compared with pure fibers, Pr-doped SnO{sub 2} nanofibers exhibited excellent ethanol sensing properties at the optimum temperature of 300 °C. Maximum sensing response to ethanol was received in the fibers with 0.6 wt% Pr. The relationships between response time (recovery time) and temperature, response time (recovery time) and concentration were investigated. The results demonstrated that the high response and relatively short response/recovery time were related to surface area, adsorbed oxygen species and oxygen vacancies.

Prediction of Solvent Physical Properties using the Hierarchical Clustering Method

Science.gov (United States)

Recently a QSAR (Quantitative Structure Activity Relationship) method, the hierarchical clustering method, was developed to estimate acute toxicity values for large, diverse datasets. This methodology has now been applied to the estimate solvent physical properties including sur...

Improved dielectric properties, mechanical properties, and thermal conductivity properties of polymer composites via controlling interfacial compatibility with bio-inspired method

Science.gov (United States)

Ruan, Mengnan; Yang, Dan; Guo, Wenli; Zhang, Liqun; Li, Shuxin; Shang, Yuwei; Wu, Yibo; Zhang, Min; Wang, Hao

2018-05-01

Surface functionalization of Al2O3 nano-particles by mussel-inspired poly(dopamine) (PDA) was developed to improve the dielectric properties, mechanical properties, and thermal conductivity properties of nitrile rubber (NBR) matrix. As strong adhesion of PDA to Al2O3 nano-particles and hydrogen bonds formed by the catechol groups of PDA and the polar acrylonitrile groups of NBR, the dispersion of Al2O3-PDA/NBR composites was improved and the interfacial force between Al2O3-PDA and NBR matrix was enhanced. Thus, the Al2O3-PDA/NBR composites exhibited higher dielectric constant, better mechanical properties, and larger thermal conductivity comparing with Al2O3/NBR composites at the same filler content. The largest thermal conductivity of Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA was 0.21 W/m K, which was 122% times of pure NBR. In addition, the Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA displayed a high tensile strength about 2.61 MPa, which was about 255% of pure NBR. This procedure is eco-friendly and easy handling, which provides a promising route to polymer composites in application of thermal conductivity field.

Preparation of CuInS{sub 2}/TiO{sub 2} nanotube heterojunction arrays electrode and investigation of its photoelectrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Li, Tingting [School of Environmental Science and Technology, State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering of Ministry of Education, Dalian University of Technology, Dalian 116024, Liaoning (China); College of Civil Engineering and Architecture, Liaoning Technical University, Fuxin 123000 (China); Li, Xinyong, E-mail: xyli@dlut.edu.cn [School of Environmental Science and Technology, State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering of Ministry of Education, Dalian University of Technology, Dalian 116024, Liaoning (China); Zhao, Qidong; Teng, Wei [School of Environmental Science and Technology, State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering of Ministry of Education, Dalian University of Technology, Dalian 116024, Liaoning (China)

2014-11-15

Graphical abstract: Schematic illustration of the synthesis steps of CuInS{sub 2}/TiO{sub 2} heterojunction arrays electrode. - Highlights: • CuInS{sub 2}/TiO{sub 2} nanotube heterojunction arrays electrode was successfully fabricated via a modified SILAR method. • Morphology, chemical compositions and the photoelectrochemical properties were studied. • The formed heterojunction structure is demonstrated as n–n type heterojunction. - Abstract: CuInS{sub 2}/TiO{sub 2} nanotube heterojunction arrays electrode was synthesized via a modified successive ionic layer adsorption and reaction (SILAR) method. The morphology, crystalline structure and chemical composition of the composite electrode were characterized with field-emission scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS), respectively. The optical properties were investigated by UV–vis diffusion reflection spectra (DRS) and photoluminescence (PL) spectra as well as the photoelectrochemical measurements. Significantly enhanced photoelectrochemical properties of CuInS{sub 2}/TiO{sub 2} NTs electrode were observed under visible light irradiation, which could be attributed to the high absorption coefficient of CuInS{sub 2} in visible region and the heterostructure formed between CuInS{sub 2} and TiO{sub 2}.

Physical properties of nanostructured CeO2 thin films grown by SILAR method

Science.gov (United States)

Khan, Ishaque Ahmed; Belkhedkar, M. R.; Salodkar, R. V.; Ubale, A. U.

2018-05-01

Nanostructured CeO2 thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method onto glass substrate using (CeNO3)3 6H2O and NaOH as cationic and anionic precursors respectively. The structural and morphological characterizations were carried out by means of X-ray diffraction, FTIR, FESEM and EDX studies. The highly resistive (1010 Ω cm) semiconducting CeO2 film exhibits 2.95 eV optical band gap.

Transport properties of RCo_2B_2C with R = Dy, Ho, and Pr single

Science.gov (United States)

Duran, Alejandro; Escudero, Roberto

2002-03-01

Single crystals of (Dy, Ho, Pr)Co_2B_2C have been grown by a cold copper crucible method. Metallurgical and structural studies indicate that this borocarbide family melts incongruently and crystallizes as a derivative structure of the ThCr_2Si_2. The family accepts rare earth atoms depending on the type of transition metals used to form the compound. For instance with Ni atoms, all lanthanides ranging from the large lanthanum to lutetium ions are reported to form RNi_2B_2C single crystals, so far no single crystals have been obtained when changing Ni by Cobalt. A comparison of the structural parameters of the RCo_2B_2C with the RNiHo, Pr) compounds indicate that the atomic distance between transition metal atoms contracts with the insertion of the Co ion, resulting in an increasing of the c parameter and decreasing volume. Several recent reports published in the current literature related on the physical properties of RCo_2B_2C (R = rare earth metals and Y) have been only performed on polycrystalline samples, they commonly contain small amounts of second phases. High quality single crystals are necessaries in order to better understand the physical properties, such as anisotropy in the transport and in the magnetic properties. In this report we show magnetic susceptibility and resistivity measurements performed in single crystals in the ab-plane and c direction for 2 - 320 K temperature range for the three single crystals of (Dy, Ho, Pr)Co_2B_2C.

Structural, electronic and elastic properties of heavy fermion YbRh2 Laves phase compound

Science.gov (United States)

Pawar, Harsha; Shugani, Mani; Aynyas, Mahendra; Sanyal, Sankar P.

2018-05-01

The structural, electronic and elastic properties of YbRh2 Laves phase intermetallic compound which crystallize in cubic (MgCu2-type) structure have been investigated using ab-initio full potential linearized augmented plane wave (FP- LAPW) method with LDA and LDA+U approximation. The calculated ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B') are in good agreement with available experimental and theoretical data. The electronic properties are analyzed from band structures and density of states. Elastic constants are predicted first time for this compound which obeys the stability criteria for cubic system.

A method for measuring the inertia properties of rigid bodies

Science.gov (United States)

Gobbi, M.; Mastinu, G.; Previati, G.

2011-01-01

A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.

Molecular structure, photoluminescent and electroluminescent properties of bis(2-(4-methyl-2-hydroxyphenyl)benzothiazolate) zinc with excellent electron-transport characteristics

International Nuclear Information System (INIS)

Xu Huixia; Xu Bingshe; Fang Xiaohong; Yue Yan; Chen Liuqing; Wang Hua; Hao Yuying

2011-01-01

Highlights: → The synthesis, crystal structure and photophysical properties of Zn(4-MeBTZ) 2 were reported. → The electron-transport property was investigated by theoretical calculations and experimental. → We found that Zn(4-MeBTZ) 2 has a higher electron mobility than that of [Zn(BTZ) 2 ] 2 and the devices based on it have a lower turn-on voltage. - Abstract: In this article, the molecular structure, photoluminescent and electroluminescent properties of bis(2-(4-methyl-2-hydroxyphenyl) benzothiazolate) zinc (Zn(4-MeBTZ) 2 ) with good electron-transport characteristics were reported. This complex was identified as triclinic structure with the strong intermolecular π-π stacking interactions between the benzothiazolate/phenoxido rings and weak intramolecular hydrogen bonds by X-ray single-crystal diffraction. Quantum chemical method has been employed to investigate electron structure and charge transport property. The blue-green light emission was observed by fabricating double-layer devices using Zn(4-MeBTZ) 2 as electron-transport and NPB as hole-transport material. The performance of organic light-emitting devices based on Zn(4-MeBTZ) 2 is much better than that of the devices based on [Zn(BTZ) 2 ] 2 .

A New Numerical Method for Z2 Topological Insulators with Strong Disorder

Science.gov (United States)

Akagi, Yutaka; Katsura, Hosho; Koma, Tohru

2017-12-01

We propose a new method to numerically compute the Z2 indices for disordered topological insulators in Kitaev's periodic table. All of the Z2 indices are derived from the index formulae which are expressed in terms of a pair of projections introduced by Avron, Seiler, and Simon. For a given pair of projections, the corresponding index is determined by the spectrum of the difference between the two projections. This difference exhibits remarkable and useful properties, as it is compact and has a supersymmetric structure in the spectrum. These properties enable highly efficient numerical calculation of the indices of disordered topological insulators. The method, which we propose, is demonstrated for the Bernevig-Hughes-Zhang and Wilson-Dirac models whose topological phases are characterized by a Z2 index in two and three dimensions, respectively.

Enhancement of thermoelectric properties of Mg2Si compounds with Bi doping through carrier concentration tuning

Science.gov (United States)

Lee, Ji Eun; Cho, Sang-Hum; Oh, Min-Wook; Ryu, Byungi; Joo, Sung-Jae; Kim, Bong-Seo; Min, Bok-Ki; Lee, Hee-Woong; Park, Su-Dong

2014-07-01

The Bi-doped Mg2Si powder was fabricated with solid state reaction method and consolidated with hot pressing method and then its thermoelectric properties were investigated. The n-type transport properties were measured in all samples and temperature dependence of the electrical properties shows a behavior of degenerate semiconductors for Bi-doped samples. The electrical resistivity and the Seebeck coefficient were greatly reduced with Bi, which was mainly due to the increment of the carrier concentration. The samples have maximum carrier concentration of 8.2 × 1018 cm-3. The largest ZT value of 0.61 was achieve at 873 K for Mg2.04SiBi0.02. The Bi-doping was found to be an effective n-type dopant to adjust carrier concentration. [Figure not available: see fulltext.

PatchSurfers: Two methods for local molecular property-based binding ligand prediction.

Science.gov (United States)

Shin, Woong-Hee; Bures, Mark Gregory; Kihara, Daisuke

2016-01-15

Protein function prediction is an active area of research in computational biology. Function prediction can help biologists make hypotheses for characterization of genes and help interpret biological assays, and thus is a productive area for collaboration between experimental and computational biologists. Among various function prediction methods, predicting binding ligand molecules for a target protein is an important class because ligand binding events for a protein are usually closely intertwined with the proteins' biological function, and also because predicted binding ligands can often be directly tested by biochemical assays. Binding ligand prediction methods can be classified into two types: those which are based on protein-protein (or pocket-pocket) comparison, and those that compare a target pocket directly to ligands. Recently, our group proposed two computational binding ligand prediction methods, Patch-Surfer, which is a pocket-pocket comparison method, and PL-PatchSurfer, which compares a pocket to ligand molecules. The two programs apply surface patch-based descriptions to calculate similarity or complementarity between molecules. A surface patch is characterized by physicochemical properties such as shape, hydrophobicity, and electrostatic potentials. These properties on the surface are represented using three-dimensional Zernike descriptors (3DZD), which are based on a series expansion of a 3 dimensional function. Utilizing 3DZD for describing the physicochemical properties has two main advantages: (1) rotational invariance and (2) fast comparison. Here, we introduce Patch-Surfer and PL-PatchSurfer with an emphasis on PL-PatchSurfer, which is more recently developed. Illustrative examples of PL-PatchSurfer performance on binding ligand prediction as well as virtual drug screening are also provided. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation methods and properties of allylboranes

International Nuclear Information System (INIS)

Mikhajlov, B.M.

1976-01-01

The methods of synthesis and chemical properties of allylboron compounds of different types are considered as well as the application in organic chemistry, for example, for synthesis of 1-boroadamantane and adamantane compounds. PMR study of triallylborane reveals permanent allyl rearrangement. The paper describes the ability to complex formation, reactions with organometal compounds and some other agents, reactions with diborane and tetraalkyldiboranes, reactions with carbonyl compounds and nitriles, reactions with compounds containing activated double carbon-carbon bond, reactions with acetylene compounds, and reaction with allene compounds

Studying physical properties of CuInS2 absorber layers grown by spin coating method on different kinds of substrates

Science.gov (United States)

Amerioun, M. H.; Ghazi, M. E.; Izadifard, M.

2018-03-01

In this work, first the CuInS2 (CIS2) layers are deposited on Aluminum and polyethylene terephthalate (PET) as flexible substrates, and on glass and soda lime glass (SLG) as rigid substrates by the sol-gel method. Then the samples are analyzed by x-ray diffractomery (XRD) and atomic force microscope (AFM) to investigate the crystal structures and surface roughness of the samples. The I-V curve measurements and Seebeck effect setup are used to measure the electrical properties of the samples. The XRD data obtained for the CIS2 layers show that all the prepared samples have a single phase with a preferred orientation that is substrate-dependent. The samples grown on the rigid substrates had higher crystallite sizes. The results obtained for the optical measurements indicate the dependence of the band gap energy on the substrate type. The measured Seebeck coefficient showed that the carriers were of p-type in all the samples. According to the AFM images, the surface roughness also varied in the CIS2 layers with different substrates. In this regard, the type of substrate could be an important parameter for the final performance of the fabricated CIS2 cells.

Electronic and optical properties of bilayer PbI2: a first-principles study

Science.gov (United States)

Shen, Chenhai; Wang, Guangtao

2018-01-01

By employing first-principles methods, we investigate the effects of stacking patterns and interlayer coupling on the electronic structures and optical properties of bilayer (BL) PbI2. For optical properties, excitonic effects are considered. The results show that crystal-type BL PbI2 stacking pattern is the most stable bilayer structures with the equilibrium interlayer distance of 3.27 Å and a direct band structure. Moreover, for all considered patterns, the interlayer coupling can induce the band structures to transform from indirect to direct and also the band gap values to vary from 2.56 eV to 2.62 eV. In addition, our calculations show that the exciton binding energy of the most stable pattern is 0.81 eV, and excitonic effects have obvious influences on optical responses of BL PbI2. These results may be useful to future experimental studies on optoelectronic properties of two-dimensional BL PbI2 nanosheets.

A conjugate gradient method with descent properties under strong Wolfe line search

Science.gov (United States)

Zull, N.; ‘Aini, N.; Shoid, S.; Ghani, N. H. A.; Mohamed, N. S.; Rivaie, M.; Mamat, M.

2017-09-01

The conjugate gradient (CG) method is one of the optimization methods that are often used in practical applications. The continuous and numerous studies conducted on the CG method have led to vast improvements in its convergence properties and efficiency. In this paper, a new CG method possessing the sufficient descent and global convergence properties is proposed. The efficiency of the new CG algorithm relative to the existing CG methods is evaluated by testing them all on a set of test functions using MATLAB. The tests are measured in terms of iteration numbers and CPU time under strong Wolfe line search. Overall, this new method performs efficiently and comparable to the other famous methods.

Nd2Fe14C-based magnet with better permanent magnetic properties prepared by a simple mechanochemical method

Science.gov (United States)

Geng, Hongmin; Ji, Yuan; Zhang, Jingjing; Gao, Yuchao; Yan, Yu; Wang, Wenquan; Su, Feng; Du, Xiaobo

2017-11-01

Nd2Fe14C-based magnet is prepared by a mechanochemical method, namely high-energy ball-milling Nd2Fe11Bx (x = 0-0.15) alloy in heptane (C7H16), followed by annealing to 850 °C in vacuum. Under the action of high-energy ball-milling, Nd2Fe11Bx react with heptane to form NdH2+δ, Fe-(CB), C, etc. H2 is released and Nd2Fe17, Nd2Fe17Cx (x = 0-3), Nd2Fe14C, Nd carbides and α-Fe are formed in the subsequent annealing. C amount depends on ball-milling time t. Long time ball milling or high C content suppresses the formation of 2:17 phase and favors the formation of 2:14:1 phase in the final products. Excessive ball-milling results in the quick increase of α-Fe. The maximum of magnetically hard Nd2Fe14C is obtained at t = 4 h. For Nd2Fe11 samples, there exists considerable quantity of Nd carbides and α-Fe phase appears earlier and increases rapidly with extending the ball-milling time t. The addition of B element shortens the ball-milling time of the formation of maximum Nd2Fe14C and prominently suppresses the formation of Nd carbide and α-Fe. The optimum magnetic properties, coercivity iHc of 1193.7 kA/m, remanence Mr of 580.9 kA/m, maximum magnetic energy product (BH)max of 91.7 kJ/m3 is approaching to its theoretic value of 99.2 kJ/m3 for isotropic Nd2Fe14C magnet, are obtained in Nd2Fe11B0.06 alloy ball milled for 3.5 h.

First-principles Study of the Electronic Structure and Optical Properties of MgH2

Science.gov (United States)

Alford, Ashley; Chou, Mei-Yin

2003-03-01

It has been noticed that magnesium might play an interesting role in recently discovered switchable-mirror systems. For example, the films of rare earth and magnesium alloys are found to be superior to the pure rare-earth samples in maximum transparency and mirror-state reflectivity [1]. Moreover, the magnesium-rich Ni-Mg alloy films turned out to be a switchable-mirror system without rare earths [2]. In both cases, pure transparent MgH2 is reversibly formed when these alloys take up hydrogen. In order to model the optical properties of these films, we need to know the electronic and optical properties of MgH2. In this work, we investigate its bonding characteristics, band structure, and dielectric properties with first-principles theoretical methods. The stability of the crystal and the bonding are studied using density functional theory and pseudopotential methods. The excited state properties (the quasiparticle spectra) are studied by many-body perturbation theory within the so-called GW approximation in which the electronic self-energy is approximated by the full Green's function (G) times the screened Coulomb interaction (W). We will report the results for both the rutile-structured alpha-MgH2 and the low-symmetry gamma-MgH2. [1] P. van der Sluis, M. Ouwerkerk, and P. A. Duine, Appl. Phys. Lett. 70, 3356 (1997). [2] T. J. Richardson, J. L. Slack, R. D. armitage, R. Kostecki, B. Farangis, and M. D. Rubin, Appl. Phys. Lett. 78, 3047 (2001).

Synthesis and characterization of Zn3Ta2O8 nanomaterials by hydrothermal method

International Nuclear Information System (INIS)

Bîrdeanu, M.; Bîrdeanu, A.-V.; Gruia, A.S.; Fagadar-Cosma, E.; Avram, C.N.

2013-01-01

Graphical abstract: The results of an experimental program that was focused on obtaining the Zn 3 Ta 2 O 8 nanocrystalline synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate, the results of the nanomaterial’s structure characterization and the optical spectral properties of such nanomaterials that were thoroughly investigated. Also, the experimental results are compared with ab initio calculations of electronic properties of Zn 3 Ta 2 O 8 . Highlights: •Zn 3 Ta 2 O 8 nanomaterials were synthesized by hydrothermal method and characterized. •The obtained nanomaterials has excellent phosphor, optical and morphological properties. •The material can be used in designing high performance optoelectronical devices. -- Abstract: Zn 3 Ta 2 O 8 has been synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate. The crystal structure and microstructure, phase composition and the absorption of Zn 3 Ta 2 O 8 nanomaterials were characterized by X-ray diffraction, FT/IR measurements, UV–VIS measurements, PL measurements, SEM and AFM techniques and BET analysis. XRD results show the single phase of Zn 3 Ta 2 O 8 and the average particle size that is 52 nm. This narrow nanometer size was also confirmed by AFM measurements. BET analysis revealed that the nanomaterials are mesoporous. The PL spectra show the blue luminescence of Ta 2 Zn 3 O 8 . Besides, in the present work we report ab initio calculations regarding electronic properties of Zn 3 Ta 2 O 8 ; the theoretical results are compared with the experimental ones

Characterization and microwave dielectric properties of Mg{sub 2}YVO{sub 6} ceramic

Energy Technology Data Exchange (ETDEWEB)

Su, Chia-Hui; Wang, Yi-Sheng; Huang, Cheng-Liang, E-mail: huangcl@mail.ncku.edu.tw

2015-08-25

Highlights: • Study the microwave dielectric properties and microstructure of Mg{sub 2}YVO{sub 6}. • Mg{sub 2}YVO{sub 6} possesses excellent dielectric properties. • Both extrinsic and intrinsic factors have effects on Q × f of specimens. - Abstract: Tetragonal-structured Mg{sub 2}YVO{sub 6} ceramics were prepared by conventional solid-state method, and their physical and microwave dielectric properties were investigated for the first time. The forming of Mg{sub 2}YVO{sub 6} main phase was confirmed by XRD diffraction pattern. XPS and Raman spectrum were recorded to clarify the chemical states of elements and vibration and rotation modes of the specimen, respectively. In addition, the relationships between sintering temperature, packing fraction, and microwave dielectric properties in Mg{sub 2}YVO{sub 6} ceramics were also studied. The new microwave dielectric material Mg{sub 2}YVO{sub 6} ceramics sintered at 1290 °C for 4 h has a dielectric constant (ε{sub r}) of ∼10.88, a Q × f of ∼68,300 GHz (f = 10.389 GHz), and a τ{sub f} ∼ −53.9 ppm/°C, demonstrating a candidate for microwave application.

Testing methods for antimicrobial activity of TiO2 photocatalyst

Directory of Open Access Journals (Sweden)

Markov Siniša L.

2014-01-01

Full Text Available In recent years, a lot of commercial TiO2 photocatalyst products have been developed and extensively studied for prospective and safe antimicrobial application in daily life, medicine, laboratories, food and pharmaceutical industry, waste water treatments and in development of new self-cleaning and antimicrobial materials, surfaces and paints. This paper reviews the studies published worldwide on killing microorganisms, methods for testing the antimicrobial activity, light sources and intensities, as well as calculation methods usually used when evaluating the antimicrobial properties of the TiO2-based products. Additionally, some strengths and weaknesses of the available methods for testing the antimicrobial activity of TiO2 photocatalyst products have been pointed out.[Projekat Ministarstva nauke Republike Srbije, br. III45008

Sr2CeO4: Electronic and structural properties

International Nuclear Information System (INIS)

Rocha, Leonardo A.; Schiavon, Marco A.; Nascimento, Clebio S.; Guimarães, Luciana; Góes, Márcio S.; Pires, Ana M.; Paiva-Santos, Carlos O.

2014-01-01

Highlights: • Sr 2 CeO 4 it was obtained from the heat treatment of Ce 3+ -doped strontium oxalate. • Rietveld analysis made it possible to obtain information about crystalline structure. • Experimental band gap value was compared with theoretical obtained by Sparkle/PM7. • The materials obtained shows intense photoluminescence and scintillator properties. - Abstract: This work presents on the preparation and photoluminescent properties of Sr 2 CeO 4 obtained from the heat treatment of Ce(III)-doped strontium oxalate (10, 25 and 33 mol%). The oxalate precursors were heat treated at 1100 °C for 12 h. The structure of this photoluminescent material was evaluated by the Rietveld method. The route used in this work to prepare the materials showed to be viable when compared to other synthesis reported in the literature. The Sr 2 CeO 4 material showed a broad and intense band emission with a maximum around 485 nm. The quantitative phase analysis showed that the Sr 2 CeO 4 photoluminescent phase is the majority one compared to the impurity phases of SrCeO 3 and SrCO 3 . From all results it was possible to verify a complete elimination of the CeO 2 phase for the sample obtained from the heat treatment of oxalate precursor containing 33 mol% of cerium(III). The material showed excellent properties for possible candidate as scintillator materials, and in the improvement of efficiency of solar cells when excited in the UV–vis region. The CIE chromaticity diagram it is also reported in this work

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method.

Science.gov (United States)

Wong, Yinting; Zhong, Dan; Song, Aotian; Hu, Yan

2017-04-26

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153°) but a lower sliding angle (16°) than F-SCHGM, with a contact angle of 141.2° and a sliding angle of 67°. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m·K), was quite like the original HGM, which was 0.0475 W/(m·K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m·K) and 0.0543 W/(m·K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

Sensing and electrical properties of TiO2 nanoparticles

International Nuclear Information System (INIS)

Usman, M.

2011-01-01

The purpose of this work was to synthesize TiO 2 nanoparticles using Coprecipitation method. 2 different samples were synthesized, one with a modifier and other without using a modifier. After synthesis, newly formed nanoparticles were characterized b different techniques to find various properties of these nanoparticles. Scanning electron Microscopy (SEM) was used to study structure and morphology of Cu nanoparticles and for compositional analysis Energy dispersive spectroscopy (EDS) was used. X-Ray Diffraction (XRD) Studies were also carried out to find phase an average particle Size. To find the band gap of our nanoparticles, UV-Visible Spectroscopy was also done. Non-Modified nanoparticles were as small as 12nm reported by SEM images which were synthesized using a modifier were as small as 10nm. Modified TiO 2 nanoparticles were used in humidity sensing devices and it properties as a humidity sensor were examined by doing Impedance spectroscopy, D measurements and Dielectric measurements. Our TiO 2 humidity sensor showed sensitivity for humidity at low and mid-range frequencies while its response time was 4 seconds when we changed RH% to 90 from 40% and measured the impedance. (author)

Preparation and photoluminescence properties of Mn2+-activated M2Si5N8 (M = Ca, Sr, Ba) phosphors

NARCIS (Netherlands)

Duan, C.J.; Otten, W.M.; Delsing, A.C.A.; Hintzen, H.T.J.M.

2008-01-01

Mn2+-doped M2Si5N8 (M=Ca, Sr, Ba) phosphors have been prepared by a solid-state reaction method at high temperature and their photoluminescence properties were investigated. The Mn2+-activated M2Si5N8 phosphors exhibit narrow emission bands in the wavelength range of 500–700 nm with peak center at

Properties of ZnO/CuInSe/sub 2/ heterojunctions

International Nuclear Information System (INIS)

Qiu, C.X.; Shih, I.

1986-01-01

Low resistivity thin films of ZnO have been prepared by an rf sputtering technique with a target containing indium. It was found that the electrical resistivity of the deposited ZnO films was dependent on the indium content in the films. The deposition method was used to form ZnO/CuInSe/sub 2/ heterojunctions on Bridgman-grown monocrystalline CuInSe/sub 2/ samples. Electrical properties of the heterojunctions have been investigated. Spectral photovoltage variation was also measured

A critical appraisal of the zero-multipole method: Structural, thermodynamic, dielectric, and dynamical properties of a water system.

Science.gov (United States)

Wang, Han; Nakamura, Haruki; Fukuda, Ikuo

2016-03-21

We performed extensive and strict tests for the reliability of the zero-multipole (summation) method (ZMM), which is a method for estimating the electrostatic interactions among charged particles in a classical physical system, by investigating a set of various physical quantities. This set covers a broad range of water properties, including the thermodynamic properties (pressure, excess chemical potential, constant volume/pressure heat capacity, isothermal compressibility, and thermal expansion coefficient), dielectric properties (dielectric constant and Kirkwood-G factor), dynamical properties (diffusion constant and viscosity), and the structural property (radial distribution function). We selected a bulk water system, the most important solvent, and applied the widely used TIP3P model to this test. In result, the ZMM works well for almost all cases, compared with the smooth particle mesh Ewald (SPME) method that was carefully optimized. In particular, at cut-off radius of 1.2 nm, the recommended choices of ZMM parameters for the TIP3P system are α ≤ 1 nm(-1) for the splitting parameter and l = 2 or l = 3 for the order of the multipole moment. We discussed the origin of the deviations of the ZMM and found that they are intimately related to the deviations of the equilibrated densities between the ZMM and SPME, while the magnitude of the density deviations is very small.

A critical appraisal of the zero-multipole method: Structural, thermodynamic, dielectric, and dynamical properties of a water system

Energy Technology Data Exchange (ETDEWEB)

Wang, Han, E-mail: wang-han@iapcm.ac.cn [CAEP Software Center for High Performance Numerical Simulation, Huayuan Road 6, 100088 Beijing, China and Zuse Institute Berlin (ZIB), Berlin (Germany); Nakamura, Haruki [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukuda, Ikuo, E-mail: ifukuda@protein.osaka-u.ac.jp [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2016-03-21

We performed extensive and strict tests for the reliability of the zero-multipole (summation) method (ZMM), which is a method for estimating the electrostatic interactions among charged particles in a classical physical system, by investigating a set of various physical quantities. This set covers a broad range of water properties, including the thermodynamic properties (pressure, excess chemical potential, constant volume/pressure heat capacity, isothermal compressibility, and thermal expansion coefficient), dielectric properties (dielectric constant and Kirkwood-G factor), dynamical properties (diffusion constant and viscosity), and the structural property (radial distribution function). We selected a bulk water system, the most important solvent, and applied the widely used TIP3P model to this test. In result, the ZMM works well for almost all cases, compared with the smooth particle mesh Ewald (SPME) method that was carefully optimized. In particular, at cut-off radius of 1.2 nm, the recommended choices of ZMM parameters for the TIP3P system are α ≤ 1 nm{sup −1} for the splitting parameter and l = 2 or l = 3 for the order of the multipole moment. We discussed the origin of the deviations of the ZMM and found that they are intimately related to the deviations of the equilibrated densities between the ZMM and SPME, while the magnitude of the density deviations is very small.

Rehydration properties of hybrid method dried fruit enriched by natural components

Science.gov (United States)

Kowalska, Hanna; Marzec, Agata; Kowalska, Jolanta; Ciurzyńska, Agnieszka; Samborska, Kinga; Bialik, Michał; Lenart, Andrzej

2018-04-01

The aim of the study was to determine the impact of osmotic pre-dehydration and drying of fruit on the rehydration properties of dried fruit. Herein, the effect of fruit juice, applied as a natural enriching substance was very important. In addition, the properties of dried fruits obtained through combined air-drying and subsequent microwave-vacuum drying with `puffing' effect were similar to the freeze-dried fruits, but showed other rehydration properties. As raw material, frozen strawberry (Honeoye variety) and fresh apples (Idared variety) were used in the study. The apples and partially defrosted strawberries were prior dehydrated in solutions of sucrose and a mixture of sucrose with chokeberry juice concentrate at 50°C for 2 h. Next, the fruit samples were dried by one of two ways: air-drying (50°C, 5 h) and microwavevacuum drying for about 360 s; and freeze-drying (30°C, 63 Pa, 24 h). The rehydration was carried out in distilled water (20°C, 5 h). The osmotic pre-dehydration hindered fruit drying process. The impact of drying method became particularly evident while examining the kinetics of rehydration. During the rehydration of the pre-dehydrated dried fruit a slower hydration could be observed. Freeze-dried strawberries absorbed 2-3 times more water than those dried by the `puffing' effect.

Microstructure, Mechanical and Tribological Properties of Ag/Bi2Sr2CaCu2O x Self-lubricating Composites

Science.gov (United States)

Tang, Hua; Zhang, Du; Wang, Yuqi; Zhang, Yi; Ji, Xiaorui; Song, Haojie; Li, Changsheng

2014-01-01

Ag/Bi2Sr2CaCu2O x self-lubricating composites were successfully fabricated by a facile powder metallurgy method. The structure and morphology of the as-synthesized composites and the worn surface after tribometer testing are characterized by using X-ray diffraction and scanning electron microscopy together with energy dispersive spectrometry. The results indicated that self-lubricating composites are composed of superconductor phase and Ag phase. Moreover, the effects of Ag on mechanical and tribological properties of the novel composites were investigated. The friction test results showed that the friction coefficient of the pure Bi2212 against stainless steel is about 0.40 at ambient temperature and abruptly decreases to about 0.17 when the temperature is cooled to 77 K. The friction coefficients of the composites from room temperature to high temperature were lower and more stable than those of pure Bi2Sr2CaCu2O x . When the content of Ag is 10 wt.%, the Ag/Bi2Sr2CaCu2O x composites exhibited excellent tribological performance, the improved tribological properties are attributed to the formation of soft metallic Ag films at the contacted zone of the composites.

Health effects estimation: Methods and results for uranium mill tailings contaminated properties

International Nuclear Information System (INIS)

Denham, D.H.; Cross, F.T.; Soldat, J.K.

1990-01-01

This paper describes methods for estimating potential health effects from exposure to uranium mill tailings and presents a summary of risk projections for 50 contaminated properties (residences, schools, churches, and businesses) in the US. The methods provide realistic estimates of cancer risk to exposed individuals based on property-specific occupancy and contamination patterns. External exposure to gamma radiation, inhalation of radon daughters, and consumption of food products grown in radium-contaminated soil are considered. Most of the projected risk was from indoor exposure to radon daughters; however, for some properties the risk from consumption of locally grown food products is similar to that from radon daughters. In all cases, the projected number of lifetime cancer deaths for specific properties is less than one, but for some properties the increase in risk over that normally expected is greater than 100%

Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

Science.gov (United States)

Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

2018-05-01

Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

Optical and structural properties of CuSbS2 thin films grown by thermal evaporation method

International Nuclear Information System (INIS)

Rabhi, A.; Kanzari, M.; Rezig, B.

2009-01-01

Structural, optical and electrical properties of CuSbS 2 thin films grown by thermal evaporation have been studied relating the effects of substrate heating conditions of these properties. The CuSbS 2 thin films were carried out at substrate temperatures in the temperature range 100-200 deg. C . The structure and composition were characterized by XRD, SEM and EDX. X-ray diffraction revealed that the films are (111) oriented upon substrate temperature 170 deg. C and amorphous for the substrate temperatures below 170 deg. C . No secondary phases are observed for all the films. The optical absorption coefficients and band gaps of the films were estimated by optical transmission and reflection measurements at room temperature. Strong absorption coefficients in the range 10 5 -10 6 cm -1 at 500 nm were found. The direct gaps Eg lie between 0.91-1.89 eV range. It is observed that there is a decrease in optical band gap Eg with increasing the substrate temperature. Resistivity of 0.03-0.96 Ω cm, in dependence on substrate temperature was characterized. The all unheated films exhibit p-type conductivity. The characteristics reported here also offer perspective for CuSbS 2 as an absorber material in solar cells applications

26 CFR 1.263A-2 - Rules relating to property produced by the taxpayer.

Science.gov (United States)

2010-04-01

... disbursements method of accounting. (2) Definition of a contract—(i) General rule. Except as provided under... financial institutions incur to originate loans. (ii) Intellectual or creative property. For purposes of...) Introduction. This paragraph (b) provides a simplified method for determining the additional section 263A costs...

Magnetic Properties of Copper Doped Nickel Ferrite Nanoparticles Synthesized by Co Precipitation Method

Science.gov (United States)

Anjana, V.; John, Sara; Prakash, Pooja; Nair, Amritha M.; Nair, Aravind R.; Sambhudevan, Sreedha; Shankar, Balakrishnan

2018-02-01

Nickel ferrite nanoparticles with copper atoms as dopant have been prepared using co-precipitation method with general formula Ni1-xCuxFe2O4 (x=0.2, 0.4, 0.6, 0.8 and 1) and are sintered at quite ambient temperature. Structural and magnetic properties were examined using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction method (XRD) and Vibrating Sample Magnetometer (VSM) to study the influence of copper doping in nickel ferrite magnetic nanoparticles. X-ray studies proves that the particles are possessing single phase spinel structure with an average particle size calculated using Debye Scherer formula. Magnetic measurements reveal that saturation magnetization value (Ms) decreases while magnetic coercivity (Hc) increases upon doping.

Influence of Co{sup 2+} on the structural and magnetic properties of substituted magnetites obtained by the coprecipitation method

Energy Technology Data Exchange (ETDEWEB)

Velásquez, A. A., E-mail: avelas26@eafit.edu.edu.co [Universidad EAFIT, Grupo de Electromagnetismo Aplicado (Colombia); Urquijo, J. P. [Universidad de Antioquia, Grupo de Estado Sólido, Instituto de Física (Colombia)

2015-06-15

In this paper we report the effect of divalent cobalt on the structural and magnetic properties of substituted magnetites, Fe {sub 3−x}Co {sub x}O{sub 4}, with γ=Co {sup 2+}/Fe = 0, 5, 10, 15, 20 and 30 % wt, synthesized by the coprecipitation method. The samples were characterized by Atomic Absorption Spectroscopy, X-ray Diffraction, room temperature Mössbauer Spectroscopy and Vibrating Sample Magnetometry. The effect of Co {sup 2+} was found to depend strongly of the concentration employed in the synthesis process. For γ≤15 % the Co {sup 2+} promotes the formation of particles more crystalline and with higher saturation magnetization, remanence and coercivity than those obtained in absence of this cation. A sequential increasing of the lattice parameter is observed, as well as a reduction in the hyperfine magnetic field of the Fe {sup 2.5+}sub spectrum, while the hyperfine magnetic field of the Fe {sup 3+}sub spectrum keeps almost constant. For γ=20 % and 30 % the crystallinity of the samples decreases, particle size distribution effects are evidenced and the saturation magnetization decreases drastically. The results suggest that for low Co {sup 2+} contents the substitution of Fe {sup 3+}by Co {sup 2+} at octahedral sites of the inverse spinel system is the dominant effect, while for the highest concentrations used the substitution of Fe {sup 2+} by Co {sup 2+} and the increasing of the particle size distribution are the dominant effects.

Microstructure and thermoelectric properties of CuInSe2/In2Se3 compound

Science.gov (United States)

Wang, Kang; Feng, Jing; Ge, Zhen-Hua; Qin, Peng; Yu, Jie

2018-01-01

CuInSe2 powders were synthesized by solvothermal method, and then the CuInSe2/In2Se3 bulk samples were fabricated by spark plasma sintering (SPS) technique. To investigate the phase composition, the powders were determined by X-ray diffraction (XRD). The microstructures of the powders and bulk samples were observed by scanning electron microscopy (SEM). The transportation of the electronic properties and thermal conductivity were measured at room temperature to 700 K. According to the results, the CuInSe2 powders appeared in flower-like patterns which ranged from 3 μm to 6 μm. CuInSe2 powders were synthesized at 180∘C with a chalcopyrite structure. The Seebeck coefficient increased significantly in composite thermoelectric materials up to 200μVṡK-1 at 623 K. The thermal conductivity of the sample significantly decreases from the room temperature to 700 K. The CuInSe2 bulk composite by solvothermal method achieves the highest ZT value of 0.187 at 700 K.

Effects of TiO2 addition on microwave dielectric properties of Li2MgSiO4 ceramics

Science.gov (United States)

Rose, Aleena; Masin, B.; Sreemoolanadhan, H.; Ashok, K.; Vijayakumar, T.

2018-03-01

Silicates have been widely studied for substrate applications in microwave integrated circuits owing to their low dielectric constant and low tangent loss values. Li2MgSiO4 (LMS) ceramics are synthesized through solid-state reaction route using TiO2 as an additive to the pure ceramics. Variations in dielectric properties of LMS upon TiO2 addition in different weight percentages (0.5, 1.5, 2) are studied by keeping the sintering parameters constant. Crystalline structure, phase composition, and microstructure of LMS and LMS-TiO2 ceramics were studied using x-ray diffraction spectrometer and High Resolution Scanning electron microscope. Density was measured through Archimedes method and the microwave dielectric properties were examined by Cavity perturbation technique. LMS achieved relative permittivity (ε r) of 5.73 and dielectric loss (tan δ) of 5.897 × 10‑4 at 8 GHz. In LMS-TiO2 ceramics, 0.5 wt% TiO2 added LMS showed comparatively better dielectric properties than other weight percentages where ε r = 5.67, tan δ = 7.737 × 10‑4 at 8 GHz.

Defect properties of CuCrO2: A density functional theory calculation

International Nuclear Information System (INIS)

Fang Zhi-Jie; Zhu Ji-Zhen; Zhou Jiang; Mo Man

2012-01-01

Using the first-principles methods, we study the formation energetics properties of intrinsic defects, and the charge doping properties of extrinsic defects in transparent conducting oxides CuCrO 2 . Intrinsic defects, some typical acceptor-type, and donor-type extrinsic defects in their relevant charge state are considered. By systematically calculating the formation energies and transition energy, the results of calculation show that, V Cu , O i , and O Cu are the relevant intrinsic defects in CuCrO 2 ; among these intrinsic defects, V Cu is the most efficient acceptor in CuCrO 2 . It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO 2 because of their deep transition energy level. For all the acceptor-type extrinsic defects, substituting Mg for Cr is the most prominent doping acceptor with relative shallow transition energy levels in CuCrO 2 . Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO 2 . (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Structural Ceramic Nanocomposites: A Review of Properties and Powders’ Synthesis Methods

Science.gov (United States)

Palmero, Paola

2015-01-01

Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional properties, a deep understanding of the materials’ behavior across length scales is necessary. In fact, knowing how the nanoscale structure influences the bulk properties enables the design of increasingly performing composite materials. A further key point is the ability of tailoring the desired nanostructured features in the sintered composites, a challenging issue requiring a careful control of all stages of manufacturing, from powder synthesis to sintering. This review is divided into four parts. In the first, classification and general issues of nanostructured ceramics are reported. The second provides basic structure–property relations, highlighting the grain-size dependence of the materials properties. The third describes the role of nanocrystalline second-phases on the mechanical properties of ordinary grain sized ceramics. Finally, the fourth part revises the mainly used synthesis routes to produce nanocomposite ceramic powders, underlining when possible the critical role of the synthesis method on the control of microstructure and properties of the sintered ceramics. PMID:28347029

Development and Validation of Marker-Aided Selection Methods for Wood Property Traits in Loblolly Pine and Hybrid Poplar

Energy Technology Data Exchange (ETDEWEB)

Tuskan, G.A.

2001-06-20

Wood properties influence pulp and paper quality. Certainly, overall pulp yields are directly related to the cellulose content, changes in hemicellulose content are associated with changes in pulp cohesiveness, and pulping efficiency is related to lignin content. Despite the importance of wood properties on product quality, little progress has been made in improving such traits because current methods of assessing wood and fiber characteristics are time-consuming, expensive, and often imprecise. Genetic improvement of wood and fiber properties has been further hampered by the large size of trees, delayed reproductive maturity and long harvest cycles. Recent developments in molecular genetics will help overcome the physical, economic and biological constraints in assessing and improving wood properties. Genetic maps consisting of numerous molecular markers are now available for loblolly pine and hybrid poplar. Such markers/maps may be used as part of a marker-aided selection and breeding effort or to expedite the isolation and characterization of genes and/or promoters that directly control wood properties. The objectives of this project are: (1) to apply new and rapid analytical techniques for assessing component wood properties to segregating F2 progeny populations of loblolly pine and hybrid poplar, (2) to map quantitative trait loci and identify molecular markers associated with wood properties in each of the above species and (3) to validate marker-aided selection methods for wood properties in loblolly pine and hybrid poplar.

Calculation of dynamic and electronic properties of perfect and defect crystals by semiempirical quantum mechanical methods

International Nuclear Information System (INIS)

Zunger, A.

1975-07-01

Semiempirical all-valence-electron LCAO methods, that were previously used to study the electronic structure of molecules are applied to three problems in solid state physics: the electronic band structure of covalent crystals, point defect problems in solids and lattice dynamical study of molecular crystals. Calculation methods for the electronic band structure of regular solids are introduced and problems regarding the computation of the density matrix in solids are discussed. Three models for treating the electronic eigenvalue problem in the solid, within the proposed calculation schemes, are discussed and the proposed models and calculation schemes are applied to the calculation of the electronic structure of several solids belonging to different crystal types. The calculation models also describe electronic properties of deep defects in covalent insulating crystals. The possible usefulness of the semieipirical LCAO methods in determining the first order intermolecular interaction potential in solids and an improved model for treating the lattice dynamics and related thermodynamical properties of molecular solids are presented. The improved lattice dynamical is used to compute phonon dispersion curves, phonon density of states, stable unit cell structure, lattice heat capacity and thermal crystal parameters, in α and γ-N 2 crystals, using the N 2 -N 2 intermolecular interaction potential that has been computed from the semiempirical LCAO methods. (B.G.)

Geophysical methods for determining the geotechnical engineering properties of earth materials.

Science.gov (United States)

2010-03-01

Surface and borehole geophysical methods exist to measure in-situ properties and structural : characteristics of earth materials. Application of such methods has demonstrated cost savings through : reduced design uncertainty and lower investigation c...

Optimization principles for preparation methods and properties of fine ferrite materials

Science.gov (United States)

Borisova, N. M.; Golubenko, Z. V.; Kuz'micheva, T. G.; Ol'khovik, L. P.; Shabatin, V. P.

1992-08-01

The paper is devoted to the problems of development of fine materials based on Ba-ferrite for vertical magnetic recording in particular. Taking an analogue — BaFe 12-2 xCo xTe xO 19 — we have optimized the melt co-precipitation method and shown a new opportunity to provide chemical homogeneity of microcrystallites by means of cryotechnology. Magnetic characteristics of the magnetic tape experimental sample for digital video recording are presented. A series of principles of consistent control of ferrite powder properties are formulated and illustrated with specific developments.

Estimation of mechanical properties of nanomaterials using artificial intelligence methods

Science.gov (United States)

Vijayaraghavan, V.; Garg, A.; Wong, C. H.; Tai, K.

2014-09-01

Computational modeling tools such as molecular dynamics (MD), ab initio, finite element modeling or continuum mechanics models have been extensively applied to study the properties of carbon nanotubes (CNTs) based on given input variables such as temperature, geometry and defects. Artificial intelligence techniques can be used to further complement the application of numerical methods in characterizing the properties of CNTs. In this paper, we have introduced the application of multi-gene genetic programming (MGGP) and support vector regression to formulate the mathematical relationship between the compressive strength of CNTs and input variables such as temperature and diameter. The predictions of compressive strength of CNTs made by these models are compared to those generated using MD simulations. The results indicate that MGGP method can be deployed as a powerful method for predicting the compressive strength of the carbon nanotubes.

Gas Sensing Properties of ZnO-SnO2 Nanostructures.

Science.gov (United States)

Chen, Weigen; Li, Qianzhu; Xu, Lingna; Zeng, Wen

2015-02-01

One-dimensional (1D) semiconductor metal oxide nanostructures have attracted increasing attention in electrochemistry, optics, magnetic, and gas sensing fields for the good properties. N-type low dimensional semiconducting oxides such as SnO2 and ZnO have been known for the detection of inflammable or toxic gases. In this paper, we fabricated the ZnO-SnO2 and SnO2 nanoparticles by hydrothermal synthesis. Microstructure characterization was performed using X-ray diffraction (XRD) and surface morphologies for both the pristine and doped samples were observed using field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Then we made thin film gas sensor to study the gas sensing properties of ZnO-SnO2 and SnO2 gas sensor to H2 and CO. A systematic comparison study reveals an enhanced gas sensing performance for the sensor made of SnO2 and ZnO toward H2 and CO over that of the commonly applied undecorated SnO2 nanoparticles. The improved gas sensing properties are attributed to the size of grains and pronounced electron transfer between the compound nanostructures and the absorbed oxygen species as well as to the heterojunctions of the ZnO nanoparticles to the SnO2 nanoparticles, which provide additional reaction rooms. The results represent an advance of compound nanostructures in further enhancing the functionality of gas sensors, and this facile method could be applicable to many sensing materials, offering a new avenue and direction to detect gases of interest based on composite tin oxide nanoparticles.

Superconducting property measuring system by magnetization method

International Nuclear Information System (INIS)

Ikisawa, K.; Mori, T.; Takasu, N.

1988-01-01

Superconducting property measuring system (CMS-370B) for high temperature oxide superconductor has been developed. This system adopts magnetization measurement. The superconducting properties are able to be measured automatically and continuously changing the temperature and external magnetic field. The critical current density as a function of temperature and magnetic field of high temperature superconductor YBa 2 Cu 3 O 7-y (YBCO) has been measured. This paper reports how it was confirmed that this system having the high performance and the accuracy gave the significant contribution to the superconducting material development

Electromagnetic and microwave absorption properties of single-walled carbon nanotubes and CoFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Li, Guo; Sheng, Leimei, E-mail: slmss@shu.edu.cn; Yu, Liming; An, Kang; Ren, Wei; Zhao, Xinluo, E-mail: xlzhao@shu.edu.cn

2015-03-15

Highlights: • LPA-SWCNTs have been abundantly fabricated by a facile, time-saving, economical and non-hazardous method using DC arc discharge technique in low-pressure air. • The electromagnetic and microwave absorption properties of LPA-SWCNTs, CoFe{sub 2}O{sub 4} nanocrystals and LPA-SWCNT/CoFe{sub 2}O{sub 4} nanocomposites were investigated and the LPA-SWCNT/CoFe{sub 2}O{sub 4} nanocomposites exhibited excellent microwave absorption properties. • The Debye theory and impedance matching were used to analyze the electromagnetic parameters and microwave absorption properties. - Abstract: Single-walled carbon nanotubes were facilely and abundantly synthesized by low-pressure air arc discharge method (LPA-SWCNTs), and CoFe{sub 2}O{sub 4} nanocrystals were synthesized by a nitrate citric acid sol–gel auto-ignition method. The electromagnetic and microwave absorption properties of LPA-SWCNTs, CoFe{sub 2}O{sub 4} nanocrystals and their nanocomposites were investigated. The LPA-SWCNT/CoFe{sub 2}O{sub 4} nanocomposites showed excellent microwave absorption properties. The minimum efficient reflection loss is −30.7 dB at 12.9 GHz for 10 wt% of LPA-SWCNTs in the nanocomposites, and an effective absorption bandwidth with a reflection loss below −10 dB is 7.2 GHz. The Debye equation and impedance matching were introduced to explain the microwave absorption properties. Compared with the single-component materials, the LPA-SWCNT/CoFe{sub 2}O{sub 4} nanocomposites are an excellent candidate for microwave absorbers.

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

Science.gov (United States)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-03-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

Science.gov (United States)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-06-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Effects of storage methods on time-related changes of titanium surface properties and cellular response

International Nuclear Information System (INIS)

Lu Haibin; Zhou Lei; Wan Lei; Li Shaobing; Rong Mingdeng; Guo Zehong

2012-01-01

Titanium implants are sold in the market as storable medical devices. All the implants have a certain shelf life during which they maintain their sterility, but variations of the surface properties through this duration have not been subject to a comprehensive assessment. The aim of this study was to investigate the effects of storage methods on time-related changes of titanium surface properties. Acid-etched titanium discs (Sa = 0.82 µm) were placed in a sealed container (tradition method) or submerged in the ddH 2 O/NaCl solution (0.15 mol L −1 )/CaCl 2 solution (0.15 mol L −1 ), and new titanium discs were used as a control group. SEM and optical profiler showed that surface morphology and roughness did not change within different groups, but the XPS analysis confirmed that the surface chemistry altered by different storage protocols as the storage duration increased, and the contact angle also varied with storage methods. The storage method also affected the protein adsorption capacity and cellular response on the titanium surface. All titanium discs stored in the solution maintained their excellent bioactivity even after four weeks storage time, but titanium discs stored in a traditional manner decreased substantially in an age-dependent manner. Much effort is needed to improve the storage methods in order to maintain the bioactivity of a titanium dental implant. (paper)

Synthesis, characterization of nickel aluminate nanoparticles by microwave combustion method and their catalytic properties

Energy Technology Data Exchange (ETDEWEB)

Ragupathi, C. [Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College (Autonomous), Chennai 600034 (India); Vijaya, J. Judith, E-mail: jjvijayaloyola@yahoo.co.in [Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College (Autonomous), Chennai 600034 (India); Kennedy, L. John [Materials Division, School of Advanced Sciences, Vellore Institute of Technology (VIT) University, Chennai Campus, Chennai 600127 (India)

2014-05-01

Highlights: • Simple route for the preparation of nickel aluminate. • NiAl{sub 2}O{sub 4} microwave absorbent was invented by a simple method. • High specific surface area was obtained at low temperature. • Evaluation of magnetic, optical and catalytic properties. - Abstract: Microwave combustion method (MCM) is a direct method to synthesize NiAl{sub 2}O{sub 4} nanoparticles and for the first time we report the using of Sesame (Sesame indicum L.) plant extract in the present study. Solutions of metal nitrates and plant extract as a gelling agent are subsequently combusted using microwave. The structure and morphology of NiAl{sub 2}O{sub 4} nanoparticles are investigated by X-ray diffraction (XRD), Fourier transforms infrared spectra (FT-IR), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), high resolution transmission electron microscopy (HR-TEM), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy, Brunauer–Emmett–Teller (BET) analysis and vibrating sample magnetometer (VSM). XRD pattern confirmed the formation of cubic phase NiAl{sub 2}O{sub 4}. The formation of NiAl{sub 2}O{sub 4} is also confirmed by FT-IR. The formation of NiAl{sub 2}O{sub 4} nanoparticles is confirmed by HR-SEM and HR-TEM. Furthermore, the microwave combustion leads to the formation of fine particles with uniform morphology. The magnetic properties of the synthesized NiAl{sub 2}O{sub 4} nano and microstructures were investigated by vibrating sample magnetometer (VSM) and their hysteresis loops were obtained at room temperature. Further, NiAl{sub 2}O{sub 4} prepared by MCM using Sesame (S. indicum L.) plant extract is tested for the catalytic activity toward the oxidation of benzyl alcohol.

Mechanical properties of partially meltable superconducting YBa/sub 2/Cu/sub 3/O/sub 7-x/

International Nuclear Information System (INIS)

Selvamanickam, V.; Salama, K.

1988-01-01

Partial melting has been suggested as a method for the processing of the high temperatures superconducting YBa/sub 2/Cu/sub 3/O/sub 7-x/ to improve the current carrying capacity in this material. The authors have investigated the possibility of using this method for the improvement of bulk mechanical properties in addition to those related to superconductivity. Four parameters, namely, oxygen annealing temperature, melting temperature, melting time and cooling rate are identified and studied. Each parameter is varied individually and its effects on microstructure and mechanical and superconducting properties are examined. The results indicate that the properties of superconducting YBa/sub 2/Cu/sub 3/O/sub 7-x/ can be improved significantly using the proper melting temperature, melting time, cooling rate and oxygen annealing temperature

Probing the E2 properties of the scissors mode with real photons

Science.gov (United States)

Beck, Tobias; Pietralla, Norbert; Beller, Jacob; Derya, Vera; Löher, Bastian; Savran, Deniz; Tornow, Werner; Werner, Volker; Zilges, Andreas

2018-05-01

The E2/M1 multipole mixing ratio δ1→2 of the 1+ sc → 2+ 1 γ-ray transition of 156Gd and 164Dy has been measured using the linearly polarized photon beams of the HIγS facility. The employed method of photonscattering experiments in combination with polarized, quasi-monochromatic beams and a dedicated detector setup is highly sensitive to the electric quadrupole-decay properties of the scissors mode.

Structural and luminescence properties of self-yellow emitting undoped and (Ca, Ba, Sr)-doped Zn2V2O7 phosphors synthesized by combustion method

Science.gov (United States)

Foka, Kewele E.; Dejene, Birhanu F.; Koao, Lehlohonolo F.; Swart, Hendrik C.

2018-04-01

A self-activated yellow emitting Zn2V2O7 was synthesized by combustion method. The influence of the processing parameters such as synthesis temperature and dopants concentration on the structure, morphology and luminescence properties was investigated. The X-ray diffraction (XRD) analysis confirmed that the samples have a tetragonal structure and no significant structural change was observed in varying both the synthesis temperature and the dopants concentration. The estimated average crystallite size was 78 nm for the undoped samples synthesized at different temperatures and 77 nm for the doped samples. Scanning electron microscope (SEM) images showed agglomerated hexagonal-shaped particles with straight edges at low temperatures and the shape of the particles changed to cylindrical structures at moderate temperatures. At higher temperatures, the morphology changed completely. However, the morphologies of the doped samples looked alike. The photoluminescence (PL) of the product exhibited broad emission bands ranging from 400 to 800 nm. The best luminescence intensity was observed for the undoped Zn2V2O7 samples and those synthesized at 600 ℃ . Any further increase in synthesis temperature, type and concentration of dopants led to a decrease in the luminescence intensity. The broad band emission peak of Zn2V2O7 consisted of two broad bands corresponding to emissions from the Em1 (3T2→1A1) and Em2 (3T1→1A1) transitions.

Synthesis, structural and dielectric properties of SrBi2- x La x Nb2O9 ceramics prepared by hydrothermal treatment

Science.gov (United States)

Afqir, Mohamed; Tachafine, Amina; Fasquelle, Didier; Elaatmani, Mohamed; Carru, Jean-Claude; Zegzouti, Abdelouahad; Daoud, Mohamed

2018-01-01

SrBi2- x La x Nb2O9 ( x = 0.2, 0.4 and 0.6) Aurivillius materials were prepared by hydrothermal treatment. The powder prepared by this method is highly pure and not agglomerated. The morphology of the samples was characterized by SEM. The dielectric properties of all the compositions were investigated in the temperature range from 25 °C to 500 °C and in the frequency range between 100 Hz and 1 MHz. The dielectric properties at room temperature of the proposed materials can match up with La-doped SrBi2Nb2O9 ceramics prepared via the solid-state reaction method. Partial substitution of bismuth by lanthanum greatly affects the ferroelectric-paraelectric transition temperature, as the ferroelectric-paraelectric phase transition becomes diffuse and the Curie temperature shifts toward lower temperatures typically from 375 to 290 °C. The conductivity results obtained for the samples are explained taking into account the metal-binding energies.

SnO2 nanosheets grown on graphene sheets with enhanced lithium storage properties.

Science.gov (United States)

Ding, Shujiang; Luan, Deyan; Boey, Freddy Yin Chiang; Chen, Jun Song; Lou, Xiong Wen David

2011-07-07

We demonstrate a new hydrothermal method to directly grow SnO(2) nanosheets on a graphene oxide support that is subsequently reduced to graphene. This unique SnO(2)/graphene hybrid structure exhibits enhanced lithium storage properties with high reversible capacities and good cycling performance. This journal is © The Royal Society of Chemistry 2011

Characterization and luminescent properties of Eu3+ doped Gd2Zr2O7 nanopowders

International Nuclear Information System (INIS)

Rabasovic, M.S.; Sevic, D.; Krizan, J.; Terzic, M.; Mozina, J.; Marinkovic, B.P.; Savic-Sevic, S.; Mitric, M.; Rabasovic, M.D.; Romcevic, N.

2015-01-01

Highlights: • Nanopowders Gd 2 Zr 2 O 7 doped by europium ions (Eu 3+ ) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd 2 Zr 2 O 7 ) doped by europium ions (Eu 3+ ) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the 5 D 0 → 7 F 2 long lived transition could be used as a new red light source in optical devices

The structure and properties of vacancies in Si nano-crystals calculated by real space pseudopotential methods

International Nuclear Information System (INIS)

Beckman, S.P.; Chelikowsky, James R.

2007-01-01

The structure and properties of vacancies in a 2 nm Si nano-crystal are studied using a real space density functional theory/pseudopotential method. It is observed that a vacancy's electronic properties and energy of formation are directly related to the local symmetry of the vacancy site. The formation energy for vacancies and Frenkel pair are calculated. It is found that both defects have lower energy in smaller crystals. In a 2 nm nano-crystal the energy to form a Frenkel pair is 1.7 eV and the energy to form a vacancy is no larger than 2.3 eV. The energy barrier for vacancy diffusion is examined via a nudged elastic band algorithm

Mechanical properties, microstructure and magnetic properties of composite magnet base on SrO.6Fe_2O_3 (SRM)-thermoplastic and thermoset polymer

International Nuclear Information System (INIS)

Grace Tj Sulungbudi; Aloma Karo Karo; Mujamilah; Sudirman

2010-01-01

The use of magnets in industrial applications do not always require high magnetic properties. Therefore, the use of polymer as a matrix that serves as a binder can be applied to obtain lightweight, flexible and cheap composite magnet. This report discuss composite magnet base on SrO.6Fe_2O_3(SRM)-thermoplastic and thermoset polymer. Thermoplastic polymer consist of polypropylene (PP) type of PP2 and PP10 and polyethylene (PE) type of LDPE were used. For thermoset polymer, epoxy and polyester were used. Synthesis of composite magnet based on thermoplastic polymer (PP2, PP10, LDPE) were carried using the blending method, while the thermoset composites magnet using casting method. Thermoplastic composite magnets were prepared with compositions of 50, 41, 38, 33 and 29 % weight of SRM with the blending temperature of 160 °C for LDPE and 180 °C for PP2 and PP10. For thermoset composite magnets, the compositions were 30, 40, 50 and 60 % by weight of SRM. The mechanical test conducted include tensile strength and elongation at break. Microstructure on the surface of the composite materials were observed using SEM (Scanning Electron Microscope) and the magnetic properties were measured using VSM (Vibrating Sample Magnetometer). The SEM results showed the formation of flat shape powder particle with size of 1.6 µm. In general, the mechanical properties of polypropylene polymer composite magnet are better than that using polyethylene (LDPE) binder. For polypropylene binder PP10 is better than PP2. Magnetic properties are not significantly affected by the change of polymer or binder types. (author)

Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ5-oxaphosphetanes

Directory of Open Access Journals (Sweden)

Anastasy O. Kolodiazhna

2016-10-01

Full Text Available Results of research into four-membered 2-halo-1,2λ5-oxaphosphetane phosphorus(V-heterocycles are presented. The preparation of 2-halo-1,2λ5-oxaphosphetanes by reaction of P-haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ5-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by 1Н-, 13C-, 19F- and 31Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ5-oxaphosphetanes are reviewed. The 2-chloro-1,2λ5-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans-phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ5-oxaphosphetanes are analyzed. The 2-halo-1,2λ5-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines.

Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods

Directory of Open Access Journals (Sweden)

Stachowicz M.

2017-03-01

Full Text Available The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.

On some properties of the block linear multi-step methods | Chollom ...

African Journals Online (AJOL)

The convergence, stability and order of Block linear Multistep methods have been determined in the past based on individual members of the block. In this paper, methods are proposed to examine the properties of the entire block. Some Block Linear Multistep methods have been considered, their convergence, stability and ...

Properties of C4F7N–CO2 thermal plasmas: thermodynamic properties, transport coefficients and emission coefficients

Science.gov (United States)

Wu, Yi; Wang, Chunlin; Sun, Hao; Murphy, Anthony B.; Rong, Mingzhe; Yang, Fei; Chen, Zhexin; Niu, Chunpin; Wang, Xiaohua

2018-04-01

The thermophysical properties, including composition, thermodynamic properties, transport coefficients and net emission coefficients, of thermal plasmas formed from pure iso-C4 perfluoronitrile C4F7N and C4F7N–CO2 mixtures are calculated for temperatures from 300 to 30 000 K and pressures from 0.1 to 20 atm. These gases have received much attention as alternatives to SF6 for use in circuit breakers, due to the low global warming potential and good dielectric properties of C4F7N. Since the parameters of the large molecules formed in the dissociation of C4F7N are unavailable, the partition function and enthalpy of formation were calculated using computational chemistry methods. From the equilibrium composition calculations, it was found that when C4F7N is mixed with CO2, CO2 can capture C atoms from C4F7N, producing CO, since the system consisting of small molecules such as CF4 and CO has lower energy at room temperature. This is in agreement with previous experimental results, which show that CO dominates the decomposition products of C4F7N–CO2 mixtures; it could limit the repeated breaking performance of C4F7N. From the point of view of chemical stability, the mixing ratio of CO2 should therefore be chosen carefully. Through comparison with common arc quenching gases (including SF6, CF3I and C5F10O), it is found that for the temperature range for which electrical conductivity remains low, pure C4F7N has similar ρC p (product of mass density and specific heat) properties to SF6, and higher radiative emission coefficient, properties that are correlated with good arc extinguishing capability. For C4F7N–CO2 mixtures, the electrical conductivity is very close to that of SF6 while the ρC p peak at 7000 K caused by decomposition of CO implies inferior interruption capability to that of SF6. The calculated properties will be useful in arc simulations.

Structural, dynamical & electronic properties of CaCuO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Agrawal, B.K.; Agrawal, S. [Allahabad Univ. (India)

1994-12-31

The scalar relativistic version of an accurate first principles full potential self- consistent linearized muffin tin orbital (LMTO) method has been employed for describing the physical properties of the parent system of the high-Tc oxide superconductors, i.e., CaCuO2. The presently employed modified version of the LMTO method is quite fast and goes beyond the usual LMTO-ASA method in the sense that it permits a completely general shape of the potential and the charge density. Also, in contrast to LMTO-ASA, the present method is also capable of treating distorted lattice structures accurately. The calculated values of the lattice parameters of pure CaCuO2 lie within 3% of the experimentally measured values for the Sr-doped system Ca(.86)Sr(.14)CuO(2). The computed electronic structures and the density of states is quite similar to those of the other oxide superconductors, except of their three- dimensional character because of the presence of strong coupling between the closely spaced CuO2 layers. The van Hove singularity peak appears slightly below the Fermi level and a small concentration of oxygenation /or/ substitutional doping may pin it as the Fermi level. The calculated frequencies for some symmetric frozen phonons for undoped CaCuO2 are quite near to the measured data for the Sr-doped CaCuO2.

Structural and magnetic properties of SiO2–CaO–Na2O–P2O5 containing BaO–Fe2O3 glass–ceramics

International Nuclear Information System (INIS)

Leenakul, W.; Kantha, P.; Pisitpipathsin, N.; Rujijanagul, G.; Eitssayeam, S.; Pengpat, K.

2013-01-01

The incorporation method was employed to produce bioactive glass–ceramics from the BaFe 12 O 19 –SiO 2 –CaO–Na 2 O–P 2 O 5 glass system. The ferrimagnetic BaFe 12 O 19 was first prepared using a simple mixed oxide method, where the oxide precursors of 45S5 bioglass were initially mixed and then melted to form glass. The devitrification of Na 3 Ca 6 (PO 4 ) 5 and Fe 3 O 4 was observed in all of the quenched glass samples. The glass samples were then subjected to a heat treatment schedule for further crystallization. It was found that the small traces of BaFe 12 O 19 phases started to crystallize in high BF content samples of 20 and 40 wt%. These samples also exhibited good magnetic properties comparable to that of other magnetic glass–ceramics. The bioactivity of the BF glass–ceramics improved with increasing BF content as was evident by the formation of bone-like apatite layers on the surface of all of the glass–ceramics after soaking in SBF for 14 days. The results support the use of these bioactive glass–ceramics for hyperthermia treatment within the human body. - Highlights: ►BF addition improves the magnetic property and bioactivity of 45S5 bioglasses.►Bioglass-ceramics exhibited soft magnetic properties with Mr=14.850 emu/g.►Magnetic property can be enhanced by crystallization of BF in 45S5 bioglasses.

Thermal properties of Na2MoO4(s) and Na2Mo2O7(s) by high-temperature Calvet calorimetry in the temperature range 335 K to 760 K

International Nuclear Information System (INIS)

Iyer, V.S.; Agarwal, Renu; Roy, K.N.; Venkateswaran, R.S.; Venugopal, V.; Sood, D.D.

1990-01-01

Enthalpy increment measurements were made on Na 2 MoO 4 and Na 2 Mo 2 O 7 in the temperature range 335 K to 760 K by the drop method using a high-temperature Calvet calorimeter. The calorimeter was calibrated using an electrical method and synthetic sapphire SRM-720(Al 2 O 3 ). An on-line computer was used for acquiring and processing results from the calorimeter. The enthalpy increments for Na 2 MoO 4 and Na 2 Mo 2 O 7 were least-squares fitted to a polynomial with temperature and are given. The thermal properties of Na 2 MoO 4 and Na 2 Mo 2 O 7 were obtained using the above experimental values. These are the first experimental results on the thermal properties of these compounds. (author)

Investigation of superior electro-optical properties of SnO{sub 2}/SiO{sub 2} nanocomposite over its individual counterpart SnO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Naveen Kumar, P.; Sahaya Selva Mary, J.; Chandrakala, V.; Jothi Jeyarani, W.; Merline Shyla, J., E-mail: jmshyla@gmail.com

2017-06-01

A comparative investigation of SnO{sub 2}/SiO{sub 2} nanocomposite with SnO{sub 2} nanoparticles has been conducted in the present study with the intent of learning the probable enhancement of the properties of the nanocomposite over those of the bare nanoparticles which has not been widely reported before. SnO{sub 2} nanoparticles and SnO{sub 2}/SiO{sub 2} nanocomposite have been synthesized via the facile and versatile sol-gel method. The samples were characterized with X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), Brunauer Emmett Teller (BET) studies, Fourier Transform Infra-Red spectroscopy (FT-IR), UV–Visible (UV–Vis) spectroscopy and Field-dependent photo conductivity technique for the evaluation of their crystallite size, structure & morphology, surface, chemical, optical and electrical properties respectively. Scherrer’s equation was used to determine the crystallite size of the as-synthesized samples from the XRD data. The particle size of SnO{sub 2}/SiO{sub 2} nanocomposite as observed through HRSEM was found to be reduced when compared with the bare SnO{sub 2} nanoparticles suggesting a possible increase in the optical band gap of the former which has been further confirmed in the optical studies. The surface area of SnO{sub 2}/SiO{sub 2} nanocomposite revealed a remarkable enrichment by approximately 5 folds in comparison with that of SnO{sub 2} nanoparticles which suggests an enhancement in its corresponding optical and electrical properties. The SnO{sub 2}/SiO{sub 2} nanocomposite recorded appreciated values of field-dependent photo and dark currents with several folds of augmentation thereby qualifying as an efficient photoconducting material. Attributed with an improved surface area and increased photoconducting nature, the SnO{sub 2}/SiO{sub 2} nanocomposite could be presented as an excellent photoanode material for nanomaterials based Dye Sensitized Solar Cells (DSSCs). - Highlights: • SnO{sub 2}/SiO{sub 2

Synthesis and characterization of physical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} semi-nanoflower phosphor

Energy Technology Data Exchange (ETDEWEB)

Bagheri, A.; Rezaee Ebrahim Saraee, Kh.; Shakur, H.R. [University of Isfahan, Department of Nuclear Engineering, Faculty of Advance Sciences and Technologies, Isfahan (Iran, Islamic Republic of); Zamani Zeinali, H. [Nuclear Science and Technology Research Institute, Agriculture, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of)

2016-05-15

Pure gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S) and trivalent praseodymium-doped gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S:Pr{sup 3+}) scintillators with semi-nanoflower crystalline structures were successfully synthesized through a precipitation method and subsequent calcination treatment as a converter for X-ray imaging detectors. The characterization such as the crystal structures and nanostructure of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator measured by XRD and FeE-SEM experiment. The optical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator were studied. Luminescence spectra of Gd{sub 2}O{sub 2}S:Pr{sup 3+} under 320 nm UV excitation show a green emission at near 511 nm corresponding to the {sup 3}P{sub 0}-{sup 3}H{sub 4} of Pr ions. After scintillation properties of synthesized Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator investigated, Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillating film fabricated on a glass substrate by a sedimentation method. X-ray imaging of the fabricated scintillators confirmed that the Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator could be used for radiography applications in which good spatial resolution is needed. (orig.)

Evaluation of magnetic properties of NI-ZN ferrites obtained by different synthesis methods

International Nuclear Information System (INIS)

Simoes, A.N.; Neiva, L.S.; Simoes, V.N.; Gama, L.; Gomes Filho, A.C.; Oliveira, J.B.L.

2012-01-01

Ceramic oxides that exhibit ferromagnetic behavior represent important commercial products for the electronics industry and are commonly known as ferrites. The Ni-Zn ferrites are considered to be one of the most versatile and soft due to its high electrical resistivity and low eddy current losses. Thus, this study aims to evaluate the magnetic properties of Ni-Zn ferrite obtained by the Pechini and combustion reaction. After synthesis the powders were characterized by XRD, SEM, BET and magnetic measurements. The results showed that for both methods of synthesis used was the formation of the spinel phase of Ni-Zn ferrite. The micrographs show that the powders obtained by both methods have regular shapes and spherical. Were determined by BET surface area is 26 m 2 /g by the Pechini and 13 m 2 /g by combustion. And the samples synthesized by Pechini method obtained the best magnetic characteristics (author)

PRODUCTION, DIELECTRIC PROPERTY AND MICROWAVE ABSORPTION PROPERTY OF SiC(Fe SOLID SOLUTION POWDER BY SOL-GEL METHOD

Directory of Open Access Journals (Sweden)

XIAOLEI SU

2014-03-01

Full Text Available SiC(Fe solid solution powders were synthesized by sol–gel method under different reaction time, using methyltriethoxysilane as the silicon and carbon source and analytic ferric chloride as the dopant, respectively. The synthesized powders have been characterized by XRD, SEM and Raman spectra. Results show that the lattice constant decreases with increasing reaction time. The electric permittivities of SiC samples were determined in the frequency range of 8.2 ~ 12.4 GHz. Results show that the permittivity of SiC decreases with increasing reaction time. The SiC(Fe solid solution powder with reaction time of 4 h with 2 mm thickness exhibit the best microwave absorption property in X-band range (8.2 - 12.4 GHz. The microwave absorption mechanism has been discussed.

Microstructure and mechanical properties investigation of in situ TiB2 and ZrB2 reinforced Al-4Cu composites

Science.gov (United States)

Lutfi Anis, Ahmad; Ramli, Rosmamuhammadani; Darham, Widyani; Zakaria, Azlan; Talari, Mahesh Kumar

2016-02-01

Conventional Al-Cu alloys exhibit coarse grain structure leading to inferior mechanical properties in as-cast condition. Expensive thermo-mechanical treatments are needed to improve microstructure and corresponding mechanical properties. In situ Al-based composites were developed to improve mechanical properties by dispersion strengthening and grain refinement obtained by the presence of particulates in the melt during solidification. In this work Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 in situ composites were prepared by liquid casting method. XRD, electron microscopy and mechanical tests were performed on suitably sectioned and metallographically prepared surfaces to investigate the phase distribution, hardness and tensile properties. It was found that the reinforcement particles were segregated along the grain boundaries of Al dendrites. Tensile fracture morphology for both Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 were analyzed and compared to determine the fracture propagation mechanism in the composites. Al-4Cu-3ZrB2 in situ composites displayed higher strength and hardness compared to Al-4Cu-3TiB2 which could be ascribed to the stronger interfacial bonding between the Al dendrites and ZrB2 particulates as evidenced from fractographs.

Effect of Uncertainties in CO2 Property Databases on the S-CO2 Compressor Performance

International Nuclear Information System (INIS)

Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu; Cha, Je Eun

2013-01-01

Various S-CO 2 Brayton cycle experiment facilities are on the state of construction or operation for demonstration of the technology. However, during the data analysis, S-CO 2 property databases are widely used to predict the performance and characteristics of S-CO 2 Brayton cycle. Thus, a reliable property database is very important before any experiment data analyses or calculation. In this paper, deviation of two different property databases which are widely used for the data analysis will be identified by using three selected properties for comparison, C p , density and enthalpy. Furthermore, effect of above mentioned deviation on the analysis of test data will be briefly discussed. From this deviation, results of the test data analysis can have critical error. As the S-CO 2 Brayton cycle researcher knows, CO 2 near the critical point has dramatic change on thermodynamic properties. Thus, it is true that a potential error source of property prediction exists in CO 2 properties near the critical point. During an experiment data analysis with the S-CO 2 Brayton cycle experiment facility, thermodynamic properties are always involved to predict the component performance and characteristics. Thus, construction or defining of precise CO 2 property database should be carried out to develop Korean S-CO 2 Brayton cycle technology

Critical assessment of suitable methods used for determination of antibacterial properties at photocatalytic surfaces

Energy Technology Data Exchange (ETDEWEB)

Krysa, Josef, E-mail: Josef.Krysa@vscht.cz [Institute of Chemical Technology Prague, Department of Water Technology and Environmental Engineering, Technicka 5, CZ-166 28 Prague (Czech Republic); Musilova, Eva [Institute of Chemical Technology Prague, Department of Water Technology and Environmental Engineering, Technicka 5, CZ-166 28 Prague (Czech Republic); Zita, Jiri [Institute of Chemical Technology Prague, Department of Inorganic Technology, Technicka 5, CZ-166 28 Prague (Czech Republic)

2011-11-15

Highlights: {yields} Methods for antibacterial activity of irradiated TiO{sub 2} films were critically assessed. {yields} As test bacteria gram negative E. coli and gram positive E. faecalis were employed. {yields} The ISO glass adhesion method is more appropriate than method with bacteria suspension. {yields} Some improvements of the ISO method were suggested. - Abstract: This work describes the development of methods necessary for antibacterial effect evaluation on irradiated TiO{sub 2} layers. Two methods using bacteria suspensions and the glass adhesion method (based on ISO 27447:2009(E)) were critically assessed and compared. As test bacteria gram negative Escherichia coli and gram positive Enterococcus faecalis were employed. The method using 50 cm{sup 3} of bacteria suspension is convenient for testing layers with strong antibacterial effect (prepared from powder photocatalysts). For the evaluation of the antibacterial effect of sol gel layers, the glass adhesion method based on the ISO is more appropriate than the method with 3 cm{sup 3} of bacteria suspension. The reason is that the later does not allow a distinction between the inhibition effect of TiO{sub 2} and UV light itself. Some improvements of the ISO method were suggested, namely the use of gelatinous pills (CCM) of bacteria, using saline solution instead of nutrient broth for bacteria suspension preparation and the application of selective media for bacteria cultivation. Decreasing the light intensity from 0.6 mW cm{sup -2} to 0.2 mW cm{sup -2} (fulfilling the requirements of the ISO) results in almost negligible effect of UV light itself, thus enabling proper testing of the antibacterial properties of TiO{sub 2} thin films.

Critical assessment of suitable methods used for determination of antibacterial properties at photocatalytic surfaces

International Nuclear Information System (INIS)

Krysa, Josef; Musilova, Eva; Zita, Jiri

2011-01-01

Highlights: → Methods for antibacterial activity of irradiated TiO 2 films were critically assessed. → As test bacteria gram negative E. coli and gram positive E. faecalis were employed. → The ISO glass adhesion method is more appropriate than method with bacteria suspension. → Some improvements of the ISO method were suggested. - Abstract: This work describes the development of methods necessary for antibacterial effect evaluation on irradiated TiO 2 layers. Two methods using bacteria suspensions and the glass adhesion method (based on ISO 27447:2009(E)) were critically assessed and compared. As test bacteria gram negative Escherichia coli and gram positive Enterococcus faecalis were employed. The method using 50 cm 3 of bacteria suspension is convenient for testing layers with strong antibacterial effect (prepared from powder photocatalysts). For the evaluation of the antibacterial effect of sol gel layers, the glass adhesion method based on the ISO is more appropriate than the method with 3 cm 3 of bacteria suspension. The reason is that the later does not allow a distinction between the inhibition effect of TiO 2 and UV light itself. Some improvements of the ISO method were suggested, namely the use of gelatinous pills (CCM) of bacteria, using saline solution instead of nutrient broth for bacteria suspension preparation and the application of selective media for bacteria cultivation. Decreasing the light intensity from 0.6 mW cm -2 to 0.2 mW cm -2 (fulfilling the requirements of the ISO) results in almost negligible effect of UV light itself, thus enabling proper testing of the antibacterial properties of TiO 2 thin films.

The magnetic properties of copper metaborate CuB2O4

International Nuclear Information System (INIS)

Petrakovskij, G.A.; Pankrats, A.I.; Popov, M.A.; Balaev, A.D.; Velikanov, D.A.; Vorotynov, A.M.; Sablina, K.A.; Roessli, B.; Schefer, J.; Amato, A.; Staub, U.; Boehm, M.; Ouladdiaf, B.; Boehm, M.

2002-01-01

The experimental data on the magnetic and resonant properties, thermal capacity, muon spin relaxation and neutron scattering of copper metaborate CuB 2 O 4 single crystals are reviewed. The results of the symmetry analysis and modeling by the method of phenomenological thermodynamic potential are cited. The magnetic structure of the crystal in various temperature ranges of magnetic ordering is discussed

Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

DEFF Research Database (Denmark)

Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt

1996-01-01

Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...

Structural properties of metal-organic frameworks within the density-functional based tight-binding method

Energy Technology Data Exchange (ETDEWEB)

Lukose, Binit; Supronowicz, Barbara; Kuc, Agnieszka B.; Heine, Thomas [School of Engineering and Science, Jacobs University Bremen (Germany); Petkov, Petko S.; Vayssilov, Georgi N. [Faculty of Chemistry, University of Sofia (Bulgaria); Frenzel, Johannes [Lehrstuhl fuer Theoretische Chemie, Ruhr-Universitaet Bochum (Germany); Seifert, Gotthard [Physikalische Chemie, Technische Universitaet Dresden (Germany)

2012-02-15

Density-functional based tight-binding (DFTB) is a powerful method to describe large molecules and materials. Metal-organic frameworks (MOFs), materials with interesting catalytic properties and with very large surface areas, have been developed and have become commercially available. Unit cells of MOFs typically include hundreds of atoms, which make the application of standard density-functional methods computationally very expensive, sometimes even unfeasible. The aim of this paper is to prepare and to validate the self-consistent charge-DFTB (SCC-DFTB) method for MOFs containing Cu, Zn, and Al metal centers. The method has been validated against full hybrid density-functional calculations for model clusters, against gradient corrected density-functional calculations for supercells, and against experiment. Moreover, the modular concept of MOF chemistry has been discussed on the basis of their electronic properties. We concentrate on MOFs comprising three common connector units: copper paddlewheels (HKUST-1), zinc oxide Zn{sub 4}O tetrahedron (MOF-5, MOF-177, DUT-6 (MOF-205)), and aluminum oxide AlO{sub 4}(OH){sub 2} octahedron (MIL-53). We show that SCC-DFTB predicts structural parameters with a very good accuracy (with less than 5% deviation, even for adsorbed CO and H{sub 2}O on HKUST-1), while adsorption energies differ by 12 kJ mol{sup -1} or less for CO and water compared to DFT benchmark calculations. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Probing the E2 properties of the scissors mode with real photons

Directory of Open Access Journals (Sweden)

Beck Tobias

2018-01-01

Full Text Available The E2/M1 multipole mixing ratio δ1→2 of the 1+ sc → 2+ 1 γ-ray transition of 156Gd and 164Dy has been measured using the linearly polarized photon beams of the HIγS facility. The employed method of photonscattering experiments in combination with polarized, quasi-monochromatic beams and a dedicated detector setup is highly sensitive to the electric quadrupole-decay properties of the scissors mode.

Ag doped TiO2 nanoparticles prepared by hydrothermal method and coating of the nanoparticles on the ceramic pellets for photocatalytic study: Surface properties and photoactivity

Directory of Open Access Journals (Sweden)

Oguzhan Avciata

2018-02-01

Full Text Available In this work, Ag doped nano TiO2 photocatalysts were synthesized in powder form by hydrothermal method at 180 ºC in 120 min using different reduction agents. The synthesized powders were characterized by powder X-ray diffraction (XRD, Energydispersive X-ray spectroscopy (EDS, Surface area measurements (BET, Transmission electron microscopy (TEM and scanning electron microscopy (SEM analyses. The effect of reduction agents on the morphological properties of Ag doped nano TiO2 has been studied. We have been observed that the use of different reduction agents affects the particle size and surface area. Ag doped nano TiO2 photocatalysts were coated to the ceramic pellets by dip coating technique for photocatalytic study. Photocatalytic properties of the synthesized powder were examined in a circulating aquarium filled with indigo blue (IB solution under UV irradiation. Periodical UV spectrophotometric analysis showed that indigo blue (IB has been degraded and its concentration has decreased under UV irradiation by time.

Poly(1,4-cyclohexanedimethylene 2,6-naphthalate polyester with high melting point: Effect of different synthesis methods on molecular weight and properties

Directory of Open Access Journals (Sweden)

N. Kasmi

2018-03-01

Full Text Available In the current manuscript, a new approach for the synthesis of poly(1,4- cyclohexanedimethylene 2,6-naphthalate (PCHDMN derived from dimethyl 2,6-naphthalenedicarboxylate (2,6-DMN and 1,4-Cyclohexanedimethanol (CHDM via melt polycondensation method is introduced. The effect of three different synthesis pathways, polycondensation time and temperature on polyesters molecular weight increase has been investigated. All of the prepared samples were characterized measuring their intrinsic viscosity (IV, thermal properties and morphology with differential scanning calorimetry (DSC and wide-angle X-ray diffraction (WAXD, respectively. The results demonstrated the effectiveness of the synthesis pathway proposed for the preparation of PCHDMN, resulting in high molecular weight (IV value around 0.5 dL/g and much shorter reaction time. Melt polycondensation temperatures above melting point of polyester should be avoided to be used due to the decomposition of polyester. This was proved by thermogravimetric analysis (TGA and Pyrolysis-gas chromatography–mass spectroscopy analysis (Py-GC/MS.

A method for quantifying mechanical properties of tissue following viral infection.

Directory of Open Access Journals (Sweden)

Vy Lam

Full Text Available Viral infection and replication involves the reorganization of the actin network within the host cell. Actin plays a central role in the mechanical properties of cells. We have demonstrated a method to quantify changes in mechanical properties of fabricated model three-dimensional (3D connective tissue following viral infection. Using this method, we have characterized the impact of infection by the human herpesvirus, cytomegalovirus (HCMV. HCMV is a member of the herpesvirus family and infects a variety of cell types including fibroblasts. In the body, fibroblasts are necessary for maintaining connective tissue and function by creating mechanical force. Using this 3D connective tissue model, we observed that infection disrupted the cell's ability to generate force and reduced the cumulative contractile force of the tissue. The addition of HCMV viral particles in the absence of both viral gene expression and DNA replication was sufficient to disrupt tissue function. We observed that alterations of the mechanical properties are, in part, due to a disruption of the underlying complex actin microfilament network established by the embedded fibroblasts. Finally, we were able to prevent HCMV-mediated disruption of tissue function by the addition of human immune globulin against HCMV. This study demonstrates a method to quantify the impact of viral infection on mechanical properties which are not evident using conventional cell culture systems.

The new method of modifying the hydrophobic properties of expanded perlite

Directory of Open Access Journals (Sweden)

Vogt Elżbieta

2017-01-01

Full Text Available The progressive industrialization and development of the automotive industry is the cause of the increasing demand for chemical products, especially oil products. Unfortunately, during processing, transportation or storage of these products, they get very often into the environment causing pollution. The removal of the results of accidents is still a current problem. The techniques which employ various types of sorbents deserve special attention among the several methods of eliminating the effects of pollutions. Moreover, expanded hydrophobic perlite is an interesting material among sorbents which are used on a large scale. The new method of modifying the hydrophobic properties of expanded perlite, with the use of solutions of stearic acid in organic solvents, was presented. The perlite that was used in research was produced by the PerliPol registered partnership in Bełchatów. Hydrophobic properties of the obtained materials were determined on the basis of the results achieved due to the modified film flotation method, “floating on water” test and on the basis of the value of water retention for individual samples. All grain fractions of perlite obtained hydrophobic properties which were better than or comparable to the hydrophobic properties of the HydroPerl (PerlPol commercial material used to remove petroleum product pollution. The hydrophobization process significantly improved the adsorption capacity of modified perlite to petroleum product pollution.

Photoluminescence properties of Gd_2O_3:Eu"3"+ for solid state lighting

International Nuclear Information System (INIS)

Ukare, R.S.; Zade, G.D.; Dhoble, S.J.

2016-01-01

We synthesized Gd_2O_3 doped europium (III) (1 m%) nanophosphors using the precipitation method and combustion method. The synthesized nanophosphors were characterized by X-ray diffraction (XRD) and SEM techniques. The optical properties of the synthesized nanophosphors were investigated by photoluminescence spectroscopy. The XRD patterns of Gd_2O_3 revealed formation of desired cubic phase by both methods. The XRD of nanophosphors synthesized by both methods were highly consistent with standard JCPDS file of Gd_2O_3 indicating no structural change with incorporation of the Eu"3"+ ions in the Gd_2O_3 matrix. Both XRD and SEM result confirms the particle size of prepared sample in nanometer range. The phosphor could be effectively excited by near UV at 395 nm. The Eu"3"+ doping of Gd_2O_3 produced red luminescence around 613 nm. The stimulated CIE chromaticity coordinates were also calculated. (author)

Determination of optical properties in nanostructured thin films using the Swanepoel method

International Nuclear Information System (INIS)

Sanchez-Gonzalez, J.; Diaz-Parralejo, A.; Ortiz, A.L.; Guiberteau, F.

2006-01-01

We present the methodological framework of the Swanepoel method for the spectrophotometric determination of optical properties in thin films using transmittance data. As an illustrative case study, we determined the refractive index, thickness, absorption index, and extinction coefficient of a nanostructured 3 mol% Y 2 O 3 -doped ZrO 2 (yttria stabilized zirconia, 3YSZ) thin film prepared by the sol-gel method and deposited by dipping onto a soda-lime glass substrate. In addition, using the absorption index obtained with the Swanepoel method, we calculated the optical band gap of the film. The refractive index was found to increase, then decrease, and finally stabilize with increasing wavelength of the radiation, while the absorption index and extinction coefficient decreased monotonically to zero. These trends are explained in terms of the location of the absorption bands. We also deduced that this 3YSZ thin film has a direct optical band gap of 4.6 eV. All these results compared well with those given in the literature for similar thin films. This suggests that the Swanepoel method has an important role to play in the optical characterization of ceramic thin films

Determination of optical properties in nanostructured thin films using the Swanepoel method

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Gonzalez, J. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Badajoz 06071 (Spain); Diaz-Parralejo, A. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Badajoz 06071 (Spain); Ortiz, A.L. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Badajoz 06071 (Spain)]. E-mail: alortiz@unex.es; Guiberteau, F. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Badajoz 06071 (Spain)

2006-06-30

We present the methodological framework of the Swanepoel method for the spectrophotometric determination of optical properties in thin films using transmittance data. As an illustrative case study, we determined the refractive index, thickness, absorption index, and extinction coefficient of a nanostructured 3 mol% Y{sub 2}O{sub 3}-doped ZrO{sub 2} (yttria stabilized zirconia, 3YSZ) thin film prepared by the sol-gel method and deposited by dipping onto a soda-lime glass substrate. In addition, using the absorption index obtained with the Swanepoel method, we calculated the optical band gap of the film. The refractive index was found to increase, then decrease, and finally stabilize with increasing wavelength of the radiation, while the absorption index and extinction coefficient decreased monotonically to zero. These trends are explained in terms of the location of the absorption bands. We also deduced that this 3YSZ thin film has a direct optical band gap of 4.6 eV. All these results compared well with those given in the literature for similar thin films. This suggests that the Swanepoel method has an important role to play in the optical characterization of ceramic thin films.

Crystal structure and magnetic properties of Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5} obtained by SHS method

Energy Technology Data Exchange (ETDEWEB)

Gebrel, Z., E-mail: z_gebrel@yahoo.com; Blanusa, J.; Kusigerski, V.; Spasojevic, V.; Mrakovic, A.; Perovic, M.; Alqat, A.

2014-01-05

Highlights: • Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5} solid solutions were synthesized for the first time by SHS method. • Ferromagnetic interactions are weakened by the induced structure changes. • Metamagnetism of the Y{sub 2}Cu{sub 2}O{sub 5} is preserved up to 15% of Mg concentration. • Significant influence of finite-size Cu–O chains is observed at low temperatures. -- Abstract: The single-phase polycrystalline samples of Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5}, x = 0.0, 0.05, 0.15 were successfully synthesized by a modified self-propagating high temperature synthesis. Effects of Mg{sup +2} substitution for Cu{sup +2} in metamagnetic Y{sub 2}Cu{sub 2}O{sub 5} on its crystal structure and magnetic properties have been analyzed by X-ray diffraction and magnetic measurements performed within 2–300 K range. Mg doping was found to introduce small distortions in the main intradimmer superexchange paths so that ferromagnetic correlations decrease with Mg concentration. More significant impact of Cu substitution was found on the low temperature magnetism due to the breaking of infinite Cu–O chains. The formation of finite size chains introduces low temperature paramagnetic contribution and reduction in Néel temperature. Overall results give a strong indication that the antiferromagnetic ordering as well as metamagnetism persists up to the 15% of the Mg concentration.

Study on time of flight property of electron optical systems by differential algebraic method

International Nuclear Information System (INIS)

Cheng Min; Tang Tiantong; Yao Zhenhua

2002-01-01

Differential algebraic method is a powerful and promising technique in computer numerical analysis. When applied to nonlinear dynamics systems, the arbitrary high-order transfer properties of the systems can be computed directly with high precision. In this paper, the principle of differential algebra is applied to study on the time of flight (TOF) property of electron optical systems and their arbitrary order TOF transfer properties can be numerically calculated out. As an example, TOF transfer properties of a uniform magnetic sector field analyzer have been studied by differential algebraic method. Relative errors of the first-order and second-order TOF transfer coefficients of the magnetic sector field analyzer are of the order 10 -11 or smaller compared with the analytic solutions. It is proved that differential algebraic TOF method is of high accuracy and very helpful for high-order TOF transfer property analysis of electron optical systems. (author)

Structural and physicochemical properties of nickel manganite NiMn{sub 2}O{sub 4-δ}synthesized by sol-gel and ultra sound assisted methods

Energy Technology Data Exchange (ETDEWEB)

Alburquenque, D. [Materials Chemistry Department, USACH, Ave L.B.O' Higgins 3363, Santiago 9170022 (Chile); Metallurgy Department, USACH, Ave Ecuador 3469, Santiago 9170124 (Chile); Troncoso, L.; Denardin, J.C. [Physics Department, USACH, Ave. Ecuador 3493, Santiago 9170124 (Chile); Butera, A. [Atomic Center, CNEA, Ito. Balseiro, Bariloche Rio Negro 84000 (Argentina); Padmasree, K.D. [Cinvestav, U.Saltillo, Monterrey Km 13.5, Saltillo CP 25900 (Mexico); Ortiz, J.; Herrera, F. [Materials Chemistry Department, USACH, Ave L.B.O' Higgins 3363, Santiago 9170022 (Chile); Marco, J.F. [Institute of Physical Chemistry “Rocasolano”, CSIC, Serrano 119, Madrid 28006 (Spain); Gautier, J.L., E-mail: juan.gautier@usach.cl [Materials Chemistry Department, USACH, Ave L.B.O' Higgins 3363, Santiago 9170022 (Chile)

2016-07-05

In this work we present the structural, magnetic and surface characterization of the ceramic nickel manganite oxide NiMn{sub 2}O{sub 4-δ} synthesized by two methods: sol-gel and ultrasound-assisted sol-gel using nitrate salts as precursors. We have characterized the non-stoichiometric samples NiMn{sub 2}O{sub 4-δ} using different physicochemical analyses. X-ray diffraction and Rietveld refinement of the X-ray data indicated that the samples crystallize in the Fd3m space group characteristic of cubic spinel-related oxides. The specific surface area of the oxides was 1.3 m{sup 2}/g (SG) and 16.3 m{sup 2}/g (UASG). SEM results showed particle agglomerates of 1.05 μm (SG) and 0.85 μm (UASG). Temperature dependence magnetization measurements were performed and a ferrimagnetic transition was identified at 103 K and 105 K depending on the preparation method (SG and UASG, respectively). The observed Curie constant was found to vary from 7.4 to 7.7 cm{sup 3} K mol{sup −1} and hysteretic magnetization vs. applied field curves at different temperatures were obtained. XPS studies of these oxides reveal the presence of Ni{sup 2+}, Mn{sup 2+}, Mn{sup 3+} and Mn{sup 4+} ions at the surface. A probable ionic distribution as a function of the synthesis method is proposed. - Highlights: • Nickel manganite was synthesized by sol gel synthesis and a novel ultrasound-assisted sol gel method. . • Bulk and surface cation distributions are proposed. • Physicochemical properties, including magnetic and surface area measurements, were studied for both types of samples.

Poly(o-phenylenediamine)/NiCoFe{sub 2}O{sub 4} nanocomposites: Synthesis, characterization, magnetic and dielectric properties

Energy Technology Data Exchange (ETDEWEB)

Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy; Anand, Siddeswaran [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Jayaprakash, Rajan [Nanotechnology Laboratory, Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

2017-02-01

In this study, poly(o-phenylenediamine) (PoPD)/NiCoFe{sub 2}O{sub 4} nanocomposites were synthesized by in-situ oxidative chemical polymerization method with different amount of NiCoFe{sub 2}O{sub 4} nanoparticles. The NiCoFe{sub 2}O{sub 4} nanoparticles were prepared by auto-combustion method. The structural, morphological, thermal properties of the synthesized PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were characterized by fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Magnetic properties of NiCoFe{sub 2}O{sub 4} nanoparticles and PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were studied by vibrating sample magnetometer (VSM). The FTIR and XRD techniques were used to confirm the formation of PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites. The average crystalline size of NiCoFe{sub 2}O{sub 4} nanoparticles and PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites were calculated from XRD. From the SEM analysis, spherical morphology of the PoPD was confirmed. The TGA results showed that the NiCoFe{sub 2}O{sub 4} nanoparticles have improved the thermal stability of PoPD. Dielectric properties of PoPD/NiCoFe{sub 2}O{sub 4} nanocomposites at different temperatures have been carried in the frequency range 50 Hz to 5 MHz. - Highlights: • Auto-combustion method was support to achieve less particle size. • Green synthesis of PoPD and nanocomposites by in-situ oxidative chemical polymerization method. • For the first time, PoPD incorporated with NiCoFe{sub 2}O{sub 4} nanoparticles. • Ferrite content affects the magnetic and dielectric properties of the nanocomposites.

41 CFR 128-1.5006-2 - Property management officer (PMO).

Science.gov (United States)

2010-07-01

... leadership, guidance, and operating procedures for personal property management functions. (b) Ensuring... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Property management officer (PMO). 128-1.5006-2 Section 128-1.5006-2 Public Contracts and Property Management Federal Property...

Synthesis and photocatalytic properties of Sn-doped TiO{sub 2} nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Tu Yafang; Huang Shengyou [Department of Physics, Wuhan University, Wuhan 430072 (China); Sang Jianping, E-mail: jpsang@acc-lab.whu.edu.c [Department of Physics, Wuhan University, Wuhan 430072 (China); Department of Physics, Jianghan University, Wuhan 430056 (China); Zou Xianwu [Department of Physics, Wuhan University, Wuhan 430072 (China)

2009-08-12

TiO{sub 2} nanotube arrays doped by Sn up to 12 at% have been prepared using template-based liquid phase deposition method. Their morphologies, structures and optical properties have been investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and photoluminescence spectroscopy. The photocatalytic properties of the samples were evaluated with the degradation of methylene blue under UV irradiation. The result shows that doping an appropriate amount of Sn can effectively improve the photocatalytic activity of TiO{sub 2} nanotube arrays, and the optimum dopant amount is found to be 5.6 at% in our experiments.

EVA/TiO2 nanocomposite: Study of the properties thermal and crystallinity of the EVA/TiO2 nanocomposite

International Nuclear Information System (INIS)

Valentim, Ana C.S.; Tavares, Maria I.B.; Silva, Emerson O. da

2011-01-01

The effect of titanium dioxide nanoparticles on the thermal properties and crystallinity of the ethylene vinyl acetate (EVA) copolymer containing 28% vinyl acetate were investigated. The EVA/TiO 2 nanocomposite films with TiO 2 contents of 0,10-1% relative to the total mass of EVA, were prepared via solution. The prepared films were characterized using TG, and XRD methods. (author)

Development and Validation of Marker-Aided Selection Methods for Wood Property Traits in Loblolly Pine and Hybrid Poplar; FINAL

International Nuclear Information System (INIS)

Tuskan, G.A.

2001-01-01

Wood properties influence pulp and paper quality. Certainly, overall pulp yields are directly related to the cellulose content, changes in hemicellulose content are associated with changes in pulp cohesiveness, and pulping efficiency is related to lignin content. Despite the importance of wood properties on product quality, little progress has been made in improving such traits because current methods of assessing wood and fiber characteristics are time-consuming, expensive, and often imprecise. Genetic improvement of wood and fiber properties has been further hampered by the large size of trees, delayed reproductive maturity and long harvest cycles. Recent developments in molecular genetics will help overcome the physical, economic and biological constraints in assessing and improving wood properties. Genetic maps consisting of numerous molecular markers are now available for loblolly pine and hybrid poplar. Such markers/maps may be used as part of a marker-aided selection and breeding effort or to expedite the isolation and characterization of genes and/or promoters that directly control wood properties. The objectives of this project are: (1) to apply new and rapid analytical techniques for assessing component wood properties to segregating F(sub 2) progeny populations of loblolly pine and hybrid poplar, (2) to map quantitative trait loci and identify molecular markers associated with wood properties in each of the above species and (3) to validate marker-aided selection methods for wood properties in loblolly pine and hybrid poplar

A method to investigate the diffusion properties of nuclear calcium.

Science.gov (United States)

Queisser, Gillian; Wittum, Gabriel

2011-10-01

Modeling biophysical processes in general requires knowledge about underlying biological parameters. The quality of simulation results is strongly influenced by the accuracy of these parameters, hence the identification of parameter values that the model includes is a major part of simulating biophysical processes. In many cases, secondary data can be gathered by experimental setups, which are exploitable by mathematical inverse modeling techniques. Here we describe a method for parameter identification of diffusion properties of calcium in the nuclei of rat hippocampal neurons. The method is based on a Gauss-Newton method for solving a least-squares minimization problem and was formulated in such a way that it is ideally implementable in the simulation platform uG. Making use of independently published space- and time-dependent calcium imaging data, generated from laser-assisted calcium uncaging experiments, here we could identify the diffusion properties of nuclear calcium and were able to validate a previously published model that describes nuclear calcium dynamics as a diffusion process.

Synthesis and electrochemical properties of ZnMn_2O_4 anode for lithium-ion batteries

International Nuclear Information System (INIS)

Feng, Chuanqi; Wang, Wei; Chen, Xiao; Wang, Shiquan; Guo, Zaiping

2015-01-01

Graphical abstract: ZnMn_2O_4 nanoparticles were prepared through the rheological phase reaction method (R-ZMO) or the mixed solvothermal method(M-ZMO). The particles of M-ZMO were clustered together to form uniform microspheres morphology. The M-ZMO behaved higher reversible capacity and better cycle performance than that of R-ZMO. - Highlights: • ZnMn_2O_4 nanoparticles were prepared through the rheological phase reaction method (R-ZMO) or the mixed solvothermal method (M-ZMO). • The M-ZMO behaved higher reversible capacity and better cycle performance than that of R-ZMO. • The morphology and cell parameters of ZnMn_2O_4 are important effects on its electrochemical properties. • The diffusion coefficient of Li"+ in M-ZMO is beneficial for M-ZMO to be used an anode. - Abstract: The precursors of ZnMn_2O_4 were synthesized by different methods (the rheological phase reaction method or the mixed solvothermal method). The precursors were heat-treated at a suitable temperature to obtain the expected product (ZnMn_2O_4). The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the samples were also investigated. The results show that ZnMn_2O_4 was synthesized successfully. The particles of ZnMn_2O_4 were irregular quasi-spheres with sizes of about 50 nm. The ZnMn_2O_4 nanoparticles synthesized through the mixed solvothermal method were clustered together to form microspheres about 1 μm in diameter. The electrochemical testing results showed that the ZnMn_2O_4 synthesized through the mixed solvothermal method featured higher reversible capacity and better cycling performance than the sample synthesized by the rheological phase reaction method. The ZnMn_2O_4 synthesized through the mixed solvothermal method could be a promising anode material for lithium ion battery application.

Growth and quantum transport properties of vertical Bi2Se3 nanoplate films on Si substrates.

Science.gov (United States)

Li, M Z; Wang, Z H; Yang, L; Pan, D S; Li, Da; Gao, Xuan; Zhang, Zhi-Dong

2018-05-14

Controlling the growth direction (planar vs. vertical) and surface-to-bulk ratio can lead to lots of unique properties for two-dimensional (2D) layered materials. We report a simple method to fabricate continuous films of vertical Bi2Se3 nanoplates on Si substrate and investigate the quantum transport properties of such films. In contrast to (001) oriented planar Bi2Se3 nanoplate film, vertical Bi2Se3 nanoplate films are enclosed by (015) facets, which possess high surface-to-bulk ratio that can enhance the quantum transport property of topological surface states. And by controlling the compactness of vertical Bi2Se3 nanoplates, we realized an effective tuning of the weak antilocalization (WAL) effect from topological surface states in Bi2Se3 films. Our work paves a way for exploring the unique transport properties of this unconventional structure topological insulator film. © 2018 IOP Publishing Ltd.

Electronic, elastic, acoustic and optical properties of cubic TiO2: A DFT approach

International Nuclear Information System (INIS)

Mahmood, Tariq; Cao, Chuanbao; Tahir, Muhammad; Idrees, Faryal; Ahmed, Maqsood; Tanveer, M.; Aslam, Imran; Usman, Zahid; Ali, Zulfiqar; Hussain, Sajad

2013-01-01

The electronic, elastic, acoustic and optical properties of cubic phases TiO 2 fluorite and pyrite are investigated using the first principles calculations. We have employed five different exchange–correlation functions within the local density and generalized gradient approximations using the ultrasoft plane wave pseudopotential method. The calculated band structures of cubic-TiO 2 elucidate that the TiO 2 fluorite and pyrite are direct and indirect semiconductors in contrast to the previous findings. From our studied properties such as bulk and shear moduli, elastic constants C 44 and Debye temperature for TiO 2 fluorite and pyrite, we infer that both the cubic phases are not superhard materials and the pyrite phase is harder than fluorite. The longitudinal and transversal acoustic wave speeds for both phases in the directions [100], [110] and [111] are determined using the pre-calculated elastic constants. In addition, we also calculate the optical properties such as dielectric function, absorption spectrum, refractive index and energy loss function using the pre-optimized structure. On the observation of optical properties TiO 2 fluorite phase turn out to be more photocatalytic than pyrite

Magnetic properties of Np2T2Sn compounds

International Nuclear Information System (INIS)

Sanchez, J.P.; Colineau, E.; Jeandey, C.; Oddou, J.L.; Rebizant, J.; Seret, A.; Spirlet, J.C.

1994-01-01

The magnetic properties of the Np 2 T 2 Sn series investigated by 237 Np Moessbauer spectroscopy are reported. Magnetic ordering is shown to occur for T = Ni, Pd, Pt, whereas the Np ions do not carry a local moment when T = Co, Ru, Rh. Comparison is made with the corresponding Np 2 T 2 In and U 2 T 2 Sn compounds. (authors). 5 refs., 3 figs

Synthesis, structure and magnetic properties of CoFe_2O_4 nanomaterial by coprecipitation method

International Nuclear Information System (INIS)

Nguyen Anh Tien; Hoang Thi Tuyet

2015-01-01

CoFe_2O_4 spinel nanomaterial has been synthesized by coprecipitation method through the hydrolysis of Co(II) and Fe(III) cations in boiling water. The results of DTA/TGA/DrTGA, XRD, TEM methods showed that CoFe_2O_4 crystals formed after a calcination at 700 °C exhibited structure of cubic with the particles size of 30-50 nm, H_c = 1526.89 Oe, M_s = 41.703 emu/g, M_r = 19.545 emu/g. (author)

Physico-Chemical Characterization and Interfacial Electrochemical Properties of Nanoparticles of Anatase-TiO2 Prepared by the Sol-Gel Method

Directory of Open Access Journals (Sweden)

Ikram Daou

2013-07-01

Full Text Available In this work, we prepared by the sol-gel method titanium dioxide nanoparticles having a large specific area (SBET = 218 m2/g. The isotherm of N2 adsorption-desorption at 77K revealed that it concerns a mesoporous solid with a maximum pore diameter of 43 Å. The X-ray diffraction showed that the solid is constituted of the anatase phase. The transmission electron microscopy revealed us that the synthesized grains of TiO2 are of nanometric sizes (diameter between 8 and 20 nm and manifest under agglomerated shape. The study of its solubility in dispersing phase, by conductometric titrations, showed that the prepared solid is totally insoluble in all the domain of the studied pH. The measured inter-facial electrochemical properties, based on the isotherms of ionic adsorption and the conductometric titrations, are: the point of zero charge found equal to 6,2±0,1, the total number of sites of surface found equal to 5,8 OH/nm2 and the nature of action of the dispersed phase on the dispersing phase which is found organizer of the structure of water. Besides, the difference of the ionizationconstants pK is found superior to 4 for all the adsorbed ions and the constants of surface complexation are independent from the nature of the adsorbed ion.

Synthesis and Magnetic Properties of Maghemite (γ-Fe2O3 Short-Nanotubes

Directory of Open Access Journals (Sweden)

Xiao XH

2010-01-01

Full Text Available Abstract We report a rational synthesis of maghemite (γ-Fe2O3 short-nanotubes (SNTs by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated γ-Fe2O3 SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (TB. The hysteresis loop was operated to show that the magnetic properties of γ-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

Prediction of Physicochemical Properties of Organic Molecules Using Semi-Empirical Methods

International Nuclear Information System (INIS)

Kim, Chan Kyung; Kim, Chang Kon; Kim, Miri; Lee, Hai Whang; Cho, Soo Gyeong

2013-01-01

Prediction of physicochemical properties of organic molecules is an important process in chemistry and chemical engineering. The MSEP approach developed in our lab calculates the molecular surface electrostatic potential (ESP) on van der Waals (vdW) surfaces of molecules. This approach includes geometry optimization and frequency calculation using hybrid density functional theory, B3LYP, at the 6-31G(d) basis set to find minima on the potential energy surface, and is known to give satisfactory QSPR results for various properties of organic molecules. However, this MSEP method is not applicable to screen large database because geometry optimization and frequency calculation require considerable computing time. To develop a fast but yet reliable approach, we have re-examined our previous work on organic molecules using two semi-empirical methods, AM1 and PM3. This new approach can be an efficient protocol in designing new molecules with improved properties

A study on native defects and magnetic properties in undoped rutile TiO2 using LDA and LDA+UO p+UTi d methods

Science.gov (United States)

Shi, Li-Bin; Wang, Yong Ping

2016-05-01

The native defects and magnetic properties in undoped rutile TiO2 are studied using local density approximation (LDA) and LDA adding Hubbard parameters (U) schemes. The band gap is adjusted to experimental value of 3.0 eV by combination of UTi d=4.2 eV and UO p=4.8 eV. This LDA+U methodology overcomes the band-gap problem and renders the approach more predictive. The formation energies of oxygen vacancy (VO), oxygen interstitial (Oi), titanium vacancy (VTi), titanium interstitial (Tii), oxygen anti-sites (OTi), and titanium anti-sites (TiO) are investigated by the LDA and LDA+U methods. In addition, some ground state configurations can be obtained by optimization of total spin. It is found that native defects can induce spin polarization and produce magnetic moment.

Effective properties of textile composites: application of the Mori–Tanaka method

DEFF Research Database (Denmark)

Skocek, Jan; Zeman, Jan; Sejnoha, Michal

2008-01-01

An efficient approach to the evaluation of effective elastic properties of plain weave textile composites using the Mori-Tanaka method is presented. The method proves its potential even if applied to real material systems with various types of imperfections including the non-uniform waviness...

Disorder-dependent valley properties in monolayer WSe2

KAUST Repository

Tran, Kha

2017-07-19

We investigate the effect of disorder on exciton valley polarization and valley coherence in monolayer WSe2. By analyzing the polarization properties of photoluminescence, the valley coherence (VC) and valley polarization (VP) are quantified across the inhomogeneously broadened exciton resonance. We find that disorder plays a critical role in the exciton VC, while affecting VP less. For different monolayer samples with disorder characterized by their Stokes shift (SS), VC decreases in samples with higher SS while VP does not follow a simple trend. These two methods consistently demonstrate that VC as defined by the degree of linearly polarized photoluminescence is more sensitive to disorder, motivating further theoretical studies.

Effects of drawing and high-pressure sintering on the superconducting properties of (Ba,K)Fe2As2 powder-in-tube wires

International Nuclear Information System (INIS)

Pyon, Sunseng; Yamasaki, Yuji; Tamegai, Tsuyoshi; Kajitani, Hideki; Koizumi, Norikiyo; Tsuchiya, Yuji; Awaji, Satoshi; Watanabe, Kazuo

2015-01-01

The evolution of the superconducting properties of round wires of (Ba,K)Fe 2 As 2 fabricated by the powder-in-tube (PIT) method is systematically studied. After establishing the method to obtain the largest transport critical current density (J c ) in round wires using the hot isostatic press technique, we investigated how the transition temperature (T c ), J c , and microstructures change at each step of the wire fabrication. Unexpectedly, we find that superconducting properties of the wire core are significantly damaged by the drawing process. Systematic measurements of J c and T c of the core superconductor after each drawing and sintering process clarified the evolution of degradation by the drawing process and recovery by heat treatment. (paper)

Nanocomposites of NR/SBR Blend Prepared by Latex Casting Method: Effects of Nano-TiO2 and Polystyrene-Encapsulated Nano-TiO2 on the Cure Characteristics, Physical Properties, and Morphology

Directory of Open Access Journals (Sweden)

Anyaporn Boonmahitthisud

2017-01-01

Full Text Available Nanocomposites of 80/20 (w/w natural rubber (NR/styrene butadiene rubber (SBR blend with four loadings of either nanosized titanium dioxide (nTiO2 or polystyrene-encapsulated nTiO2 (PS-nTiO2, ranging from 3 to 9 parts by weight per hundred of rubber (phr, were prepared by latex casting method. The PS-nTiO2 synthesized via in situ differential microemulsion polymerization displayed a core-shell morphology (nTiO2 core and PS shell with an average diameter of 42 nm. The cure characteristics (scorch time, cure time, and cure rate index, mechanical properties (tensile properties, tear strength, and hardness, thermal stability, glass transition temperature, and morphology of the prepared nanocomposites were quantified and compared. The results showed that the cure characteristics of all the nanocomposites were not significantly changed compared to those of the neat NR/SBR blend. The inclusion of an appropriate amount of either nTiO2 or PS-nTiO2 into the NR/SBR blend apparently improved the tensile strength, modulus at 300% strain, tear strength, hardness, and thermal stability but deteriorated the elongation at break of the nanocomposites. Based on differential scanning calorimetry, the glass transition temperature of all the nanocomposites was similar to that of the neat NR/SBR blend. Moreover, the morphology of the PS-nTiO2-filled rubber nanocomposites fractured surface analyzed by scanning electron microscopy showed an improvement in the interfacial adhesion between the rubber phase and the nanoparticles.

Preparation of nanostructured and nanosheets of MoS2 oxide using oxidation method.

Science.gov (United States)

Amini, Majed; Ramazani S A, Ahmad; Faghihi, Morteza; Fattahpour, Seyyedfaridoddin

2017-11-01

Molybdenum disulfide (MoS 2 ), a two-dimensional transition metal has a 2D layered structure and has recently attracted attention due to its novel catalytic properties. In this study, MoS 2 has been successfully intercalated using chemical and physical intercalation techniques, while enhancing its surface properties. The final intercalated MoS 2 is of many interests because of its low-dimensional and potential properties in in-situ catalysis. In this research, we report different methods to intercalate the layers of MoS 2 successfully using acid-treatment, ultrasonication, oxidation and thermal shocking. The other goal of this study is to form SO bonds mainly because of expected enhanced in-situ catalytic operations. The intercalated MoS 2 is further characterized using analyses such as Fourier Transform Infrared Spectroscopy (FTIR), Raman, Contact Angle, X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Microanalysis (EDAX), Transmission electron microscopy (TEM), and BET. Copyright © 2017. Published by Elsevier B.V.

Effect of kinetic properties of extraction systems on separation of some elements by liquid chromatography method with free fixed phase

International Nuclear Information System (INIS)

Fedotov, P.S.; Maryutina, T.A.; Pichugin, A.A.; Spivakov, B.Ya.

1993-01-01

Effect of kinetic properties of a series of extraction systems on the separation of certain elements by the method of liquid chromatography with free fixed phase is considered. Chromatographic behaviour of europium 3 and iron 3 ions when using systems based on di-2-ethylhexylphosphovers acid and tetraphenylmethylenediphosphine dioxide is investigated. Kinetic properties of the extraction systems used are studied by diffusion cell method with mixing, europium 3 and iron 3 mass transfer coefficients are determined

Measurement properties of exsisting clinical assessment methods evaluating scapular positioning and function. A systematic review

DEFF Research Database (Denmark)

Larsen, Camilla Marie; Juul-Kristensen, B; Lund, H

(COSMIN checklist), the methodological quality in the reliability and validity domains was ‘fair’ (57%) to ‘poor’ (43%), with only one study rated as ‘good’. The reliability domain was most often investigated. Fewof the assessment methods in the included studies that had ‘fair’ or ‘good’ measurement......MEASUREMENT PROPERTIES OF EXISTING CLINICAL ASSESSMENT METHODS EVALUATING SCAPULAR POSITIONING AND FUNCTION. A SYSTEMATIC REVIEW1,2Camilla Marie Larsen, 1,3Birgit Juul-Kristensen, 1,3Hans Lund, 1Karen Søgaard1Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark2......,2]. Rehabilitation exercises are aiming at altering abnormal/asymmetric scapular positioning and/or function. Numerous assessment methods have measured the degree of scapular dyskinesis, subjectively by visual evaluation and objectively by measurements of static and dynamic scapular positioning, by either a 3...

Effect of annealing temperature on structural, morphological and electrical properties of nanoparticles TiO{sub 2} thin films by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Muaz, A. K. M.; Hashim, U., E-mail: uda@unimap.edu.my; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L. [Institute of Nano Electronic Engineering, Univerisiti Malaysia Perlis, 01000 Kangar, Perlis (Malaysia)

2016-07-06

In this paper, the sol-gel method is used to prepare nanoparticles titanium dioxide (TiO{sub 2}) thin films at different annealing temperature. The prepared sol was deposited on the p-SiO{sub 2} substrates by spin coating technique under room temperature. The nanoparticles TiO{sub 2} solution was synthesized using Ti{OCH(CH_3)_2}{sub 4} as a precursor with an methanol solution at a molar ratio 1:10. The prepared TiO{sub 2} sols will further validate through structural, morphological and electrical properties. From the X-ray diffraction (XRD) analysis, as-deposited films was found to be amorphous in nature and tend to transform into tetragonal anatase and rutile phase as the films annealed at 573 and 773 K, respectively. The diversification of the surface roughness was characterized by atomic force microscopy (AFM) indicated the roughness and thickness very dependent on the annealing temperature. The two-point probe electrical resistance and conductance of nanoparticles TiO{sub 2} thin films were determined by the DC current-voltage (IV) analysis. From the I-V measurement, the electrical conductance increased as the films annealed at higher temperature.

Quantitative methods for reconstructing tissue biomechanical properties in optical coherence elastography: a comparison study

International Nuclear Information System (INIS)

Han, Zhaolong; Li, Jiasong; Singh, Manmohan; Wu, Chen; Liu, Chih-hao; Wang, Shang; Idugboe, Rita; Raghunathan, Raksha; Sudheendran, Narendran; Larin, Kirill V; Aglyamov, Salavat R; Twa, Michael D

2015-01-01

We present a systematic analysis of the accuracy of five different methods for extracting the biomechanical properties of soft samples using optical coherence elastography (OCE). OCE is an emerging noninvasive technique, which allows assessment of biomechanical properties of tissues with micrometer spatial resolution. However, in order to accurately extract biomechanical properties from OCE measurements, application of a proper mechanical model is required. In this study, we utilize tissue-mimicking phantoms with controlled elastic properties and investigate the feasibilities of four available methods for reconstructing elasticity (Young’s modulus) based on OCE measurements of an air-pulse induced elastic wave. The approaches are based on the shear wave equation (SWE), the surface wave equation (SuWE), Rayleigh-Lamb frequency equation (RLFE), and finite element method (FEM), Elasticity values were compared with uniaxial mechanical testing. The results show that the RLFE and the FEM are more robust in quantitatively assessing elasticity than the other simplified models. This study provides a foundation and reference for reconstructing the biomechanical properties of tissues from OCE data, which is important for the further development of noninvasive elastography methods. (paper)

Examining ion channel properties using free-energy methods.

Science.gov (United States)

Domene, Carmen; Furini, Simone

2009-01-01

Recent advances in structural biology have revealed the architecture of a number of transmembrane channels, allowing for these complex biological systems to be understood in atomistic detail. Computational simulations are a powerful tool by which the dynamic and energetic properties, and thereby the function of these protein architectures, can be investigated. The experimentally observable properties of a system are often determined more by energetic than dynamics, and therefore understanding the underlying free energy (FE) of biophysical processes is of crucial importance. Critical to the accurate evaluation of FE values are the problems of obtaining accurate sampling of complex biological energy landscapes, and of obtaining accurate representations of the potential energy of a system, this latter problem having been addressed through the development of molecular force fields. While these challenges are common to all FE methods, depending on the system under study, and the questions being asked of it, one technique for FE calculation may be preferable to another, the choice of method and simulation protocol being crucial to achieve efficiency. Applied in a correct manner, FE calculations represent a predictive and affordable computational tool with which to make relevant contact with experiments. This chapter, therefore, aims to give an overview of the most widely implemented computational methods used to calculate the FE associated with particular biochemical or biophysical events, and to highlight their recent applications to ion channels. Copyright © 2009 Elsevier Inc. All rights reserved.

Methods for partial differential equations qualitative properties of solutions, phase space analysis, semilinear models

CERN Document Server

Ebert, Marcelo R

2018-01-01

This book provides an overview of different topics related to the theory of partial differential equations. Selected exercises are included at the end of each chapter to prepare readers for the “research project for beginners” proposed at the end of the book. It is a valuable resource for advanced graduates and undergraduate students who are interested in specializing in this area. The book is organized in five parts: In Part 1 the authors review the basics and the mathematical prerequisites, presenting two of the most fundamental results in the theory of partial differential equations: the Cauchy-Kovalevskaja theorem and Holmgren's uniqueness theorem in its classical and abstract form. It also introduces the method of characteristics in detail and applies this method to the study of Burger's equation. Part 2 focuses on qualitative properties of solutions to basic partial differential equations, explaining the usual properties of solutions to elliptic, parabolic and hyperbolic equations for the archetypes...

Synthesis and photocatalytic properties of visible light responsive La/TiO2-graphene composites

International Nuclear Information System (INIS)

Khalid, N.R.; Ahmed, E.; Hong Zhanglian; Ahmad, M.

2012-01-01

Highlights: ► Synthesis of La/TiO 2 -graphene composites by two-step hydrothermal method. ► Efficient charge separation due to La doping and graphene incorporation. ► Enhanced photocatalytic activity of composite catalyst for MB degradation under visible-light. - Abstract: La/TiO 2 -graphene composites used as photocatalyst were prepared by two-step hydrothermal method. The as-prepared composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The results of optical properties of La/TiO 2 -graphene composites exhibit extended light absorption in visible-light region and possess better charge separation capability as compared to pure TiO 2 . The photocatalytic activity measurement demonstrate that La/TiO 2 -graphene composites exhibited an enhanced photocatalytic activity for methylene blue (MB) degradation under visible-light irradiation compared to pure TiO 2 , which was attributed to greater adsorptivity of dyes, extended light absorption and increased charge separation efficiency due to excellent electrical properties of graphene and the large surface contact between graphene and La/TiO 2 nanoparticles.

Nanostructure and Volatile Organic Compounds Sensing Properties of α-Fe2O3/Reduced Graphene Oxide Nanocomposite Derived by Spray Method

Science.gov (United States)

Zolghadr, S.; Kimiagar, S.; Khojier, K.

2017-12-01

This paper investigates the α-Fe2O3/reduced graphene oxide (rGO) nanocomposite as a volatile organic compounds (VOCs) sensor. The α-Fe2O3/reduced graphene oxide nanocomposites of about 370 nm thickness were synthesized by a spray method with different rGO contents (3%, 4%, and 5%) on SiO2/Si substrates. The samples were structurally and morphologically characterized by x-ray diffraction, and field emission scanning electron microscopy. These analyses showed that an increase in rGO content decreases the crystallinity of the samples. In order to study the VOCs sensing properties, the sensitivity and selectivity of the samples were tested with different VOCs vapors including ethanol, methanol, toluene, benzene, and formic acid in the temperature range of 200-400°C. The results show that the α-Fe2O3/rGO nanocomposites are more selective to ethanol than the other vapors, while an increase in rGO content decreases the sensitivity of the samples. The α-Fe2O3/rGO (3%)-based ethanol sensor also shows a good stability with respect to relative humidity in the range of 20-50% with a 1-ppm detection limit at the operating temperature of 280°C.

A FEM-based method to determine the complex material properties of piezoelectric disks.

Science.gov (United States)

Pérez, N; Carbonari, R C; Andrade, M A B; Buiochi, F; Adamowski, J C

2014-08-01

Numerical simulations allow modeling piezoelectric devices and ultrasonic transducers. However, the accuracy in the results is limited by the precise knowledge of the elastic, dielectric and piezoelectric properties of the piezoelectric material. To introduce the energy losses, these properties can be represented by complex numbers, where the real part of the model essentially determines the resonance frequencies and the imaginary part determines the amplitude of each resonant mode. In this work, a method based on the Finite Element Method (FEM) is modified to obtain the imaginary material properties of piezoelectric disks. The material properties are determined from the electrical impedance curve of the disk, which is measured by an impedance analyzer. The method consists in obtaining the material properties that minimize the error between experimental and numerical impedance curves over a wide range of frequencies. The proposed methodology starts with a sensitivity analysis of each parameter, determining the influence of each parameter over a set of resonant modes. Sensitivity results are used to implement a preliminary algorithm approaching the solution in order to avoid the search to be trapped into a local minimum. The method is applied to determine the material properties of a Pz27 disk sample from Ferroperm. The obtained properties are used to calculate the electrical impedance curve of the disk with a Finite Element algorithm, which is compared with the experimental electrical impedance curve. Additionally, the results were validated by comparing the numerical displacement profile with the displacements measured by a laser Doppler vibrometer. The comparison between the numerical and experimental results shows excellent agreement for both electrical impedance curve and for the displacement profile over the disk surface. The agreement between numerical and experimental displacement profiles shows that, although only the electrical impedance curve is

Structural and elastic properties of AIBIIIC 2 VI semiconductors

Science.gov (United States)

Kumar, V.; Singh, Bhanu P.

2018-01-01

The plane wave pseudo-potential method within density functional theory has been used to calculate the structural and elastic properties of AIBIIIC 2 VI semiconductors. The electronic band structure, density of states, lattice constants (a and c), internal parameter (u), tetragonal distortion (η), energy gap (Eg), and bond lengths of the A-C (dAC) and B-C (dBC) bonds in AIBIIIC 2 VI semiconductors have been calculated. The values of elastic constants (Cij), bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio (υ), Zener anisotropy factor (A), Debye temperature (ϴD) and G/B ratio have also been calculated. The values of all 15 parameters of CuTlS2 and CuTlSe2 compounds, and 8 parameters of 20 compounds of AIBIIIC 2 VI family, except AgInS2 and AgInSe2, have been calculated for the first time. Reasonably good agreement has been obtained between the calculated, reported and available experimental values.

The Exponentiated Gumbel Type-2 Distribution: Properties and Application

Directory of Open Access Journals (Sweden)

I. E. Okorie

2016-01-01

Full Text Available We introduce a generalized version of the standard Gumble type-2 distribution. The new lifetime distribution is called the Exponentiated Gumbel (EG type-2 distribution. The EG type-2 distribution has three nested submodels, namely, the Gumbel type-2 distribution, the Exponentiated Fréchet (EF distribution, and the Fréchet distribution. Some statistical and reliability properties of the new distribution were given and the method of maximum likelihood estimates was proposed for estimating the model parameters. The usefulness and flexibility of the Exponentiated Gumbel (EG type-2 distribution were illustrated with a real lifetime data set. Results based on the log-likelihood and information statistics values showed that the EG type-2 distribution provides a better fit to the data than the other competing distributions. Also, the consistency of the parameters of the new distribution was demonstrated through a simulation study. The EG type-2 distribution is therefore recommended for effective modelling of lifetime data.

Thermoelectric properties of Bi2SexTe3-x prepared by Bridgman method

International Nuclear Information System (INIS)

Keawprak, N.; Lao-ubol, S.; Eamchotchawalit, C.; Sun, Z.M.

2011-01-01

Highlights: → Bi 2 Se x Te 3-x with various Se concentrations grown by Bridgman method was prepared. → The electrical conductivity was found to decrease with increasing Se content. → The Seebeck coefficient was not influenced by the substitution of Te with Se. → The electronic thermal conductivity exhibited a decrease with increasing Se. → The highest of dimensionless figure of merit (ZT) was measure to be 1.2. - Abstract: Bi 2 Se x Te 3-x crystals with various x values were grown by Bridgman method. The electrical conductivity, σ, was found to decrease with increasing Se content. The highest σ of 1.6 x 10 5 S m -1 at room temperature was reached at x = 0.12 with a growth rate of 0.8 mm h -1 . The Seebeck coefficient, S, was less dependent on Se content, all with positive values showing p-type characteristics, and the highest S was measured to be 240 μV K -1 at x = 0.24. The lowest thermal conductivity, κ, was 0.7 W m -1 K -1 at x = 0.36. The electronic part of κ, κ el , showed a decrease with increasing Se content, which implies that the hole concentration as the main carriers was reduced by the addition of Se. The highest dimensionless figure of merit, ZT, at room temperature was 1.2 at x = 0.36, which is attributed to the combination of a rather high electrical conductivity and Seebeck coefficient and low thermal conductivity.

Poly(o-phenylenediamine)/NiCoFe2O4 nanocomposites: Synthesis, characterization, magnetic and dielectric properties

Science.gov (United States)

Kannapiran, Nagarajan; Muthusamy, Athianna; Chitra, Palanisamy; Anand, Siddeswaran; Jayaprakash, Rajan

2017-02-01

In this study, poly(o-phenylenediamine) (PoPD)/NiCoFe2O4 nanocomposites were synthesized by in-situ oxidative chemical polymerization method with different amount of NiCoFe2O4 nanoparticles. The NiCoFe2O4 nanoparticles were prepared by auto-combustion method. The structural, morphological, thermal properties of the synthesized PoPD/NiCoFe2O4 nanocomposites were characterized by fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Magnetic properties of NiCoFe2O4 nanoparticles and PoPD/NiCoFe2O4 nanocomposites were studied by vibrating sample magnetometer (VSM). The FTIR and XRD techniques were used to confirm the formation of PoPD/NiCoFe2O4 nanocomposites. The average crystalline size of NiCoFe2O4 nanoparticles and PoPD/NiCoFe2O4 nanocomposites were calculated from XRD. From the SEM analysis, spherical morphology of the PoPD was confirmed. The TGA results showed that the NiCoFe2O4 nanoparticles have improved the thermal stability of PoPD. Dielectric properties of PoPD/NiCoFe2O4 nanocomposites at different temperatures have been carried in the frequency range 50 Hz to 5 MHz.

Properties of Pd nanograins in C-Pd composite films obtained by PVD method

Directory of Open Access Journals (Sweden)

Kozłowski M.

2015-09-01

Full Text Available Properties of palladium nanograins obtained by sedimentation of a soluted C-Pd film prepared by PVD method are presented. These properties were studied using SEM and TEM methods. Dissolved films were prepared by PVD method and after dissolving, they were fractionated to obtain different parts classified with palladium nanograins diameters. Several classes of diameters were determined: below 20 nm, between 20 and 100 nm and above 100 nm. The defects and triple junction were observed. Multishell carbonaceous structures were found in the big and medium size Pd nanograins.

Probabilistic evaluation method of stability of ground and slope considering spatial randomness of soil properties

International Nuclear Information System (INIS)

Ohtori, Yasuki

2004-01-01

In the JEAG4601-1987 (Japan Electric Association Guide for earthquake resistance design), either the conventional deterministic method or probabilistic method is used for evaluating the stability of ground foundations and surrounding slopes in nuclear power plants. The deterministic method, in which the soil properties of 'mean ± coefficient x standard deviation' is adopted for the calculations, is generally used in the design stage to data. On the other hand, the probabilistic method, in which the soil properties assume to have probabilistic distributions, is stated as a future method. The deterministic method facilitates the evaluation, however, it is necessary to clarify the relation with the probabilistic method. In this paper, the relationship between the deterministic and the probabilistic methods are investigated. To do that, a simple model that can take into account the dynamic effect of structures and a simplified method for accounting the spatial randomness are proposed and used for the studies. As the results of studies, it is found that the strength of soil properties is most importation factor for the stability of ground structures and the probability below the safety factor evaluated with the soil properties of mean -1.0 x standard deviation' by the deterministic method is of much lower. (author)

Understanding the effect of flower extracts on the photoconducting properties of nanostructured TiO2.

Science.gov (United States)

Ansari, S G; Bhayana, Laitka; Umar, Ahmad; Al-Hajry, A; Al-Deyab, Salem S; Ansari, Z A

2012-10-01

Here we report an easy method to improve the optoelectronic properties of commercially available TiO2 nanopowder using extracts of various flowers viz. Calendula Orange (CO), Calendula Yellow (CY), Dahlia Violet (DV), Dahlia Yellow (DY), Rabbit flower (RF), Sweet Poppy (SP), Sweet Williams (SW) and their Mixed Extracts (ME). Various analysis techniques such as UV-Vis, FTIR, FESEM, XRD, and Raman spectroscopy were used to characterize for elemental, structural and morphological properties of the unmixed/mixed TiO2 nanopowder. TiO2 nanopowder was also calcined at 550 degrees C. Thick films of the these unmixed/mixed powder were printed, using conventional screen printing method, on fluorine doped tin oxide (FTO) substrate with organic binders and dried at 45 degrees C. The photoconducting properties are investigated as a function of wavelength from ultra-violet (UV) to infra-red (IR) region at a constant illumination intensity. Photocurrent gradually decreases when irradiated from UV to IR region. In case of unmixed and uncalcined TiO2, conductance decreased continuously whereas when extracts are added, a flat region of conductance is observed. The overall effect of extracts (colour pigments) is seen as an increase in the photoconductance. Highest photoconductance is observed in case of DY flower extract. Anthocyanins, present in flowers are known to have antioxidative properties and hence can contribute in photoconduction by reducing the surface adsorbed oxygen. This investigation indicates the potential use of flower extracts for dye sensitized solar cell (DSSC).

Bulk and surface properties of magnesium peroxide MgO2

Science.gov (United States)

Esch, Tobit R.; Bredow, Thomas

2016-12-01

Magnesium peroxide has been identified in Mg/air batteries as an intermediate in the oxygen reduction reaction (ORR) [1]. It is assumed that MgO2 is involved in the solid-electrolyte interphase on the cathode surface. Therefore its structure and stability play a crucial role in the performance of Mg/air batteries. In this work we present a theoretical study of the bulk and low-index surface properties of MgO2. All methods give a good account of the experimental lattice parameters for MgO2 and MgO bulk. The reaction energies, enthalpies and free energies for MgO2 formation from MgO are compared among the different DFT methods and with the local MP2 method. A pronounced dependence from the applied functional is found. At variance with a previous theoretical study but in agreement with recent experiments we find that the MgO2 formation reaction is endothermic (HSE06-D3BJ: ΔH = 51.9 kJ/mol). The stability of low-index surfaces MgO2 (001) (Es = 0.96 J/m2) and (011) (Es = 1.98 J/m2) is calculated and compared to the surface energy of MgO (001). The formation energy of neutral oxygen vacancies in the topmost layer of the MgO2 (001) surface is calculated and compared with defect formation energies for MgO (001).

Structural, electronic and elastic properties of REIr{sub 2} (RE=La and Ce) Laves phase compounds

Energy Technology Data Exchange (ETDEWEB)

Shrivastava, Deepika, E-mail: deepika89shrivastava@gmail.com; Fatima, Bushra; Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal, 462026 (India)

2016-05-23

REIr{sub 2} (RE = La and Ce) Laves phase intermetallic compounds were investigated with respect to their structural, electronic and elastic properties using full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA) as implemented in WIEN2k code. The ground state properties such as lattice constants (a{sub 0}), bulk modulus (B), pressure derivative of bulk modulus (B′) and density of state at Fermi level N(E{sub F}) have been obtained by optimization method. The electronic structure (BS, TDOS and PDOS) reveals that these Laves phase compounds are metallic in nature. The calculated elastic constants indicate that these compounds are mechanically stable at ambient pressure and found to be ductile in nature.

Design of a QA method to characterize submillimeter-sized PBS beam properties using a 2D ionization chamber array

Science.gov (United States)

Lin, Yuting; Bentefour, Hassan; Flanz, Jacob; Kooy, Hanne; Clasie, Benjamin

2018-05-01

Pencil beam scanning (PBS) periodic quality assurance (QA) programs ensure the beam delivered to patients is within technical specifications. Two critical specifications for PBS delivery are the beam width and position. The aim of this study is to investigate whether a 2D ionization chamber array, such as the MatriXX detector (IBA Dosimetry, Schwarzenbruck, Germany), can be used to characterize submillimeter-sized PBS beam properties. The motivation is to use standard equipment, which may have pixel spacing coarser than the pencil beam size, and simplify QA workflow. The MatriXX pixels are cylindrical in shape with 4.5 mm diameter and are spaced 7.62 mm from center to center. Two major effects limit the ability of using the MatriXX to measure the spot position and width accurately. The first effect is that too few pixels sample the Gaussian shaped pencil beam profile and the second effect is volume averaging of the Gaussian profile over the pixel sensitive volumes. We designed a method that overcomes both limitations and hence enables the use of the MatriXX to characterize sub-millimeter-sized PBS beam properties. This method uses a cross-like irradiation pattern that is designed to increase the number of sampling data points and a modified Gaussian fitting technique to correct for volume averaging effects. Detector signals were calculated in this study and random noise and setup errors were added to simulate measured data. With the techniques developed in this work, the MatriXX detector can be used to characterize the position and width of sub-millimeter, σ  =  0.7 mm, sized pencil beams with uncertainty better than 3% relative to σ. With the irradiation only covering 60% of the MatriXX, the position and width of σ  =  0.9 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. If one were to not use a cross-like irradiation pattern, then the position and width of σ  =  3.6 mm sized pencil beams

Morphology controlled Y{sub 2}O{sub 3}:Eu{sup 3+} nanophosphors with enhanced photoluminescence properties

Energy Technology Data Exchange (ETDEWEB)

Kumar, Deepak [School of Physics and Materials Science, Thapar University, Patiala 147003, Punjab (India); Sharma, Manoj, E-mail: manojnarad@sggswu.org [Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab (India); Pandey, O.P., E-mail: oppandey@thapar.edu [School of Physics and Materials Science, Thapar University, Patiala 147003, Punjab (India)

2015-02-15

Eu{sup 3+} doped Y{sub 2}O{sub 3} is prepared by a co-precipitation method using ammonium hydrogen carbonate as precipitating agent. In the present work we studied the effect of different molar concentrations of Poly vinyl pyrrolidone (PVP) and 1-Thio-glycerol (TG) as capping agents to enhance the optical and morphological properties of Y{sub 2}O{sub 3}:Eu{sup 3+} nanophosphors. In addition, variation of pH was studied to control the particle size of the synthesized product. The polymer concentration (TG and PVP) was also optimized at different pH to get higher luminescence of Eu{sup 3+} doped Y{sub 2}O{sub 3} nanoparticles (NPs). It was observed that pH of solution during synthesis and also its concentration affect the morphological and optical properties of Y{sub 2}O{sub 3}:Eu{sup 3+}. The structural, morphological and optical properties were studied by an X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectroscopy. XRD studies followed by Rietveld refinement confirmed the body-centered cubic structure of doped nanophosphors. It was observed that at optimized pH and polymer concentration the nanoparticles of Y{sub 2}O{sub 3}:Eu{sup 3+} have narrow size distribution and exhibited enhanced photoluminescent properties. - highlights: • Nano-sized Y{sub 2}O{sub 3}:Eu{sup 3+} were synthesized by a co-precipitation method using PVP and TG as capping agents. • Effect of polymers (PVP and TG) on morphological properties of Y{sub 2}O{sub 3}:Eu{sup 3+} has been explained in detail. • Improvement in PL intensity for Y{sub 2}O{sub 3}:Eu{sup 3+} prepared with polymers has been explained in detail.

Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes.

Science.gov (United States)

Kolodiazhna, Anastasy O; Kolodiazhnyi, Oleg I

2016-10-17

Results of research into four-membered 2-halo-1,2λ⁵-oxaphosphetane phosphorus(V)-heterocycles are presented. The preparation of 2-halo-1,2λ⁵-oxaphosphetanes by reaction of P- haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ⁵-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by ¹Н-, 13 C-, 19 F- and 31 Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ⁵-oxaphosphetanes are reviewed. The 2-chloro-1,2λ⁵-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans -phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ⁵-oxaphosphetanes are analyzed. The 2-halo-1,2λ⁵-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines.

Structural, dielectric and magnetic properties of NiFe{sub 2}O{sub 4} prepared via sol–gel auto-combustion method

Energy Technology Data Exchange (ETDEWEB)

Sun, Li, E-mail: sunlitut@163.com [Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Zhang, Ru; Wang, Zhenduo [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Ju, Lin [College of Physics and Electrical Engineering, Anyang Normal University, Anyang 455000 (China); Cao, Ensi; Zhang, Yongjia [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China)

2017-01-01

Nickelferrite (NiFe{sub 2}O{sub 4})powders were synthesized via sol–gel auto-combustion method and the corresponding temperature dependence of microstructure, dielectric and magnetic properties have been investigated. Results of XRD and SEM indicate that the NiFe{sub 2}O{sub 4} samples exhibit a typical single phase spinel structure and a uniform particle distribution. The dielectric constant and dielectric loss measurements show strong frequency dependence of all the samples. The peak observed in frequency dependence of dielectric loss measurements shifts to higher frequency with the increasing sintering temperature, indicating a Debye-like dielectric relaxation. The remanent magnetization increases with the increasing grain size while the coercivity is just the opposite. The saturation magnetization can achieve 50 emu/g when the sintering temperature is more than 1000 °C, and the lowest coercivity (159.49 Oe) was observed in the NFO sample sintered at 1300 °C for 2 h. - Highlights: • Mr value increases with the increasing grain size while Hc is just the opposite. • Ms achieve 50 emu/g when the sintering temperature is more than 1000 °C. • The lowest Hc value is 159.49 Oe for the NFO sample sintered at 1300 °C.

Photoluminescence evaluation of TiO{sub 2} synthesized by Pechini method; Avaliacao da fotoluminescencia do TiO{sub 2} sintetizado pelo metodo Pechini

Energy Technology Data Exchange (ETDEWEB)

Araujo, D.S.; Diniz, V.C.S.; Dantas, J.; Araujo, P.M.A.G.; Costa, A.C.F.M., E-mail: dagobertoufcg@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Viana, R.S.; Junior, S.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. Quimica Fundamental; Torquato, R.A. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Dept. de Engenharia de Materiais

2017-07-15

Titanium dioxide (TiO{sub 2}) stands out for use in various applications mainly due to its properties of thermal and chemical stability and its excellent optical properties. However, these properties are dependent on the type and phase morphology, which is related to the TiO{sub 2} processing method. Thus, this paper proposed to synthesize TiO{sub 2} nanoparticles by polymeric precursor method with different polymorphs, and evaluate the influence of these phases in the photoluminescent properties. For this, the stoichiometric molar proportions of citric acid:metallic cations of 1:1, 2:1, 3:1, 4:1 and 5:1 were investigated. The nanoparticles were characterized by X-ray diffraction (XRD), infrared spectroscopy, textural analysis, scanning electron microscopy (SEM), excitation and emission spectroscopy and determination of the band gap by UV-Vis diffuse reflectance spectroscopy. The presence of anatase and rutile was confirmed by XRD in different proportions for each sample. The agglomerate size increased with the citric acid/metal cations ratio as observed by SEM. Concerning photoluminescence, the maximum intensity in the emission spectrum occurred at the wavelength of 533 nm for the 3:1 sample and the maximum intensity in the excitation spectrum occurred for the 2:1 sample at the wavelength of 451 nm. (author)

Preparation of In2S3 nanopraricle by ultrasonic dispersion and its tribology property.

Science.gov (United States)

Li, Zhiwei; Tao, Xiaojun; Wu, Zhishen; Zhang, Pingyu; Zhang, Zhijun

2009-02-01

In this paper, we describe a facile and rapid method for preparing In2S3 nanoparticles via ultrasound dispersion. This method allows us to prepare In2S3 nanoparticles from bulk indium and sulfur with ease and without using expensive agents and in a short time. The possible growing mechanism of the In2S3 nanoparticles was presented. In addition, we provide detailed characterizations including TEM, XRD, TG-DTA, and XPS to study the shape, composition and structure of In2S3 nanoparticles. We also studied the tribology property of In2S3 nanoparticles made using this novel recipe.

The effect of thermo-mechanical processing on the mechanical properties of molybdenum - 2 volume % lanthana

International Nuclear Information System (INIS)

Mueller, A.J.; Shields, J.A. Jr.; Buckman, R.W. Jr.

2001-01-01

Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 volume % La 2 O 3 mill product forms, produced by CSM Industries by a wet doping process, were characterized over the temperature range of -150 o C to 1800 o C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved .material had superior creep rupture properties to recrystallized material at 1200 o C, while at 1500 o C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % La 2 O 3 to the demands of the application being considered. (author)

Phase transformation, morphology evolution and luminescence property variation in Y2O3: Eu hollow microspheres

International Nuclear Information System (INIS)

Wang, Qin; Guo, Jing; Jia, Wenjing; Liu, Baocang; Zhang, Jun

2012-01-01

Highlights: ► We report a general and facile method for the synthesis of Y 2 O 3 : Eu hollow microspheres. ► This method may be of great significance in the synthesis of many other hollow spherical materials. ► Phase, morphology and luminescence property were found to be strongly dependent on temperature and pH. ► The evolution process under various temperatures and pH values were discussed. ► The sample shows a strong red emission under short UV irradiation, and the lifetime is determined to be 7.0 ms. - Abstract: Y 2 O 3 : Eu hollow microspheres with average size of 500–600 nm have been successfully synthesized via a solvothermal method in the presence of sodium citrate as surfactant followed by a subsequent heat treatment process. High polymer F127(EO 106 PO 70 EO 106 ) served as a soft template in the formation of as prepared hollow microspheres. It is found that the pH values and the reaction temperature are two crucial factors in determining the phase, morphology and luminescence properties of the Y 2 O 3 : Eu hollow microspheres. Morphology evolution can be achieved by changing the pH and the reaction temperature. The properties of the Eu 3+ -doped Y 2 O 3 : Eu nanocrystals were characterized by XRD, FE-SEM, HR-TEM and UV–vis spectroscopy.

Effect of drying method on properties of vanadium-molybdenum oxide catalysts

International Nuclear Information System (INIS)

Gorshkova, T.P.; Savchenko, L.A.; Tarasova, D.V.; Tret'yakov, Yu.D.; Olen'kova, I.P.; Nikoro, T.A.; Maksimov, N.G.

1981-01-01

Effect of drying method of molybdenum and vanadium salt solutions on physicochemical and catalytical properties of vanadium-molybdenum catalysts is studied. It is shown that the drying method of solutions determines the completeness of vanadium binding into oxide vanadium-molybdenum compounds and thus effects the activity and selectivity of catalysts in acrolein oxidation into acrylic acid. Besides the drying method determines the porous structure of catalysts [ru

Inverse gas chromatography as a method for determination of surface properties of binding materials

Science.gov (United States)

Yu, Jihai; Lu, Xiaolei; Yang, Chunxia; Du, Baoli; Wang, Shuxian; Ye, Zhengmao

2017-09-01

Inverse gas chromatography (IGC) is a promising measurement technique for investigating the surface properties of binding materials, which are the major influence element for the adsorption performance of superplasticizer. In this work, using the IGC method, blast furnace slag (BFS), sulphoaluminate cement (SAC) and portland cement (P·O) are employed to systematically evaluate the corresponding dispersive component (γsd), specific surface free energy (γsab), and acid-base properties. The obtained results show that γsd contributes to a major section of the surface free energy in the three binding materials, suggesting they are of a relatively low polarity. Compared to the two kinds of cements, the BFS possesses the highest dispersive and specific surface free energies (the values are 45.01 mJ/m2 and 11.68 mJ/m2, respectively), and also exhibits a wider distribution range of γsd, indicating their surfaces are heterogeneous. For acid-base properties, the results indicate the surfaces of three samples are basic in nature. In addition, the adsorption investigation shows that per unit surface of BFS adsorbs the most superplasticizer molecules, which indicates the higher surface free energies is beneficial to the superplasticizer adsorption.

Process optimization and properties of magnetically hard cobalt carbide nanoparticles via modified polyol method

International Nuclear Information System (INIS)

Zamanpour, Mehdi; Bennett, Steven P.; Majidi, Leily; Chen, Yajie; Harris, Vincent G.

2015-01-01

Highlights: • High-coercivity cobalt carbides were synthesized by polyol method. • No rare earth elements were used during synthesis process. • Process parameters (reaction temperature, precursors’ concentrations, surfactants and reaction duration) were studied/optimized. • Process was scaled-up to synthesis more than 5 g powders per batch. - Abstract: Cobalt carbide magnetic nanoparticles were successfully synthesized via a modified polyol process without using a rare-earth catalyst during the synthesis process. The present results show admixtures of Co 2 C and Co 3 C phases possessing magnetization values exceeding 47 emu/g and coercivity values exceeding 2.3 kOe at room temperature. Moreover, these experiments have illuminated the important role of the reaction temperature, hydroxyl ion concentrations and the reaction duration on the crystallographic structure and magnetic properties of the nanoparticles. The crystallographic structure and particle size of the Co x C nanoparticles were characterized by X-ray diffractometry and scanning electron microscopy. Vibrating sample magnetometry was used to determine magnetic properties. Scale-up of synthesis to more than 5 g per batch was demonstrated with no significant degradation of magnetic properties

Process optimization and properties of magnetically hard cobalt carbide nanoparticles via modified polyol method

Energy Technology Data Exchange (ETDEWEB)

Zamanpour, Mehdi; Bennett, Steven P. [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Majidi, Leily [Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115 (United States); Chen, Yajie [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States)

2015-03-15

Highlights: • High-coercivity cobalt carbides were synthesized by polyol method. • No rare earth elements were used during synthesis process. • Process parameters (reaction temperature, precursors’ concentrations, surfactants and reaction duration) were studied/optimized. • Process was scaled-up to synthesis more than 5 g powders per batch. - Abstract: Cobalt carbide magnetic nanoparticles were successfully synthesized via a modified polyol process without using a rare-earth catalyst during the synthesis process. The present results show admixtures of Co{sub 2}C and Co{sub 3}C phases possessing magnetization values exceeding 47 emu/g and coercivity values exceeding 2.3 kOe at room temperature. Moreover, these experiments have illuminated the important role of the reaction temperature, hydroxyl ion concentrations and the reaction duration on the crystallographic structure and magnetic properties of the nanoparticles. The crystallographic structure and particle size of the Co{sub x}C nanoparticles were characterized by X-ray diffractometry and scanning electron microscopy. Vibrating sample magnetometry was used to determine magnetic properties. Scale-up of synthesis to more than 5 g per batch was demonstrated with no significant degradation of magnetic properties.

Improvement of mechanical properties of polymeric composites: Experimental methods and new systems

Science.gov (United States)

Nguyen, Felix Nhanchau

Filler- (e.g., particulate or fiber) reinforced structural polymers or polymeric composites have changed the way things are made. Today, they are found, for example, in air/ground transportation vehicles, sporting goods, ballistic barrier applications and weapons, electronic packaging, musical instruments, fashion items, and more. As the demand increases, so does the desire to have not only well balanced mechanical properties, but also light weight and low cost. This leads to a constant search for novel constituents and additives, new fabrication methods and analytical techniques. To achieve new or improved composite materials requires more than the identification of the right reinforcements to be used with the right polymer matrix at the right loading. Also, an optimized adhesion between the two phases and a toughened matrix system are needed. This calls for new methods to predict, modify and assess the level of adhesion, and new developments in matrix tougheners to minimize compromises in other mechanical/thermal properties. Furthermore, structural optimization, associated with fabrication (e.g., avoidance of fiber-fiber touching or particle aggregation), and sometimes special properties, such as electrical conductivity or magnetic susceptibility are necessary. Finally, the composite system's durability, often under hostile conditions, is generally mandatory. The present study researches new predictive and experimental methods for optimizing and characterizing filler-matrix adhesion and develops a new type of epoxy tougheners. Specifically, (1) a simple thermodynamic parameter evaluated by UNIFAC is applied successfully to screen out candidate adhesion promoters, which is necessary for optimization of the physio-chemical interactions between the two phases; (2) an optical-acoustical mechanical test assisted with an acoustic emission technique is developed to de-convolute filler debonding/delamination among many other micro failure events, and (3) novel core

Methods of PCM microcapsules application and the thermal properties of modified knitted fabric

Energy Technology Data Exchange (ETDEWEB)

Nejman, Alicja, E-mail: anejman@iw.lodz.pl [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland); Cieślak, Małgorzata [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland); Gajdzicki, Bogumił [Textile Research Institute, Scientific Department of Textile Chemistry and Products Modification, 5/15 Brzezinska St., 92-103 Lodz (Poland); Goetzendorf-Grabowska, Bogna; Karaszewska, Agnieszka [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland)

2014-08-10

Highlights: • We applied microcapsules containing n-octadecane for the modification of knitted fabric. • We used printing, coating and padding techniques for the application of microcapsules. • M-PCM application methods allow to regulate the thermal properties of textiles. • M-PCM application methods allow to regulate the air permeability properties of textiles. - Abstract: The aim of the study is to analyze the impact of application methods of microcapsules containing n-octadecane as phase change materials (M-PCM) on the thermal properties and air permeability of modified textile fabric. Polyester knitted fabric, printing, coating and padding methods and polymer pastes with 20 wt.% of M-PCM were used. For the assessment of modification effects the differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. DSC analysis showed that the highest enthalpy of phase transitions has printed fabric and the lowest padded fabric. The widest range of phase transitions temperatures was observed for printed fabric, slightly narrower for coated fabric and the narrowest for padded fabric. SEM analysis showed differences in the morphology of modified fabrics depending on incorporation techniques, which are compatible with differences in air permeability results. M-PCM application techniques allow to regulate the thermal and air permeability properties of fabric.

Methods of PCM microcapsules application and the thermal properties of modified knitted fabric

International Nuclear Information System (INIS)

Nejman, Alicja; Cieślak, Małgorzata; Gajdzicki, Bogumił; Goetzendorf-Grabowska, Bogna; Karaszewska, Agnieszka

2014-01-01

Highlights: • We applied microcapsules containing n-octadecane for the modification of knitted fabric. • We used printing, coating and padding techniques for the application of microcapsules. • M-PCM application methods allow to regulate the thermal properties of textiles. • M-PCM application methods allow to regulate the air permeability properties of textiles. - Abstract: The aim of the study is to analyze the impact of application methods of microcapsules containing n-octadecane as phase change materials (M-PCM) on the thermal properties and air permeability of modified textile fabric. Polyester knitted fabric, printing, coating and padding methods and polymer pastes with 20 wt.% of M-PCM were used. For the assessment of modification effects the differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. DSC analysis showed that the highest enthalpy of phase transitions has printed fabric and the lowest padded fabric. The widest range of phase transitions temperatures was observed for printed fabric, slightly narrower for coated fabric and the narrowest for padded fabric. SEM analysis showed differences in the morphology of modified fabrics depending on incorporation techniques, which are compatible with differences in air permeability results. M-PCM application techniques allow to regulate the thermal and air permeability properties of fabric

Electronic, magnetic, elastic and thermodynamic properties of Cu{sub 2}MnGa

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Sukriti [Department of Physics, Government Kamla Raja Girls Autonomous Post Graduate College, Gwalior 474001, Madhya Pradesh (India); Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India); Gupta, Dinesh C., E-mail: sosfizix@gmail.com [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India)

2016-08-01

The full-potential linearized augmented plane wave method in the stable Fm-3m phase has been implemented to investigate the structural, elastic, magnetic and electronic properties of Cu{sub 2}MnGa. The optimized equilibrium lattice parameter in stable phase is found to be 5.9495 Å. By the spin resolved density of states calculations, we have shown that the exchange splitting due to Mn atom is the main reason of ferromagnetic behavior of Cu{sub 2}MnGa. The absence of energy gap in both the spin channels predicts that the material is metallic. The total and partial density of states, elastic constants, Shear, Bulk and Young’s moduli, Zener isotropy factor, Cauchy pressure, Pugh's ductility, Kleinman parameter and Poisson's ratio are reported for the first time for the alloy. Cauchy's pressure and Pugh's index of ductility label Cu{sub 2}MnGa as ductile. Cu{sub 2}MnGa is found to be ferromagnetic and anisotropic in nature. The quasi-harmonic approximations have been employed to study the pressure and temperature dependent thermodynamic properties of Cu{sub 2}MnGa. - Highlights: • It is the first attempt to predict a variety of crystal properties of Cu{sub 2}MnGa. • Cu{sub 2}MnGa shows magnetism and hence can prove to be important in modern technology. • Cu{sub 2}MnGa is ductile and hence can attract attention of scientists and technologists.

Serotonin transporter activity of imidazolidine-2,4-dione and imidazo[2,1-f]purine-2,4-dione derivatives in aspect of their acid-base properties.

Science.gov (United States)

Zagórska, Agnieszka; Czopek, Anna; Pawłowski, Maciej; Dybała, Małgorzata; Siwek, Agata; Nowak, Gabriel

2012-11-01

Affinities of arylpiperazinylalkyl derivatives of imidazo[2,1-f]purine-2,4-dione and imidazolidine-2,4-dione for serotonin transporter and their acid-base properties were evaluated. The dissociation constant (pK(a)) of compounds 1-22 were determinated by potentiometric titration and calculated using pKalc 3.1 module of the Pallas system. The data from experimental methods and computational calculations were compared and suitable conclusions were reached.

Electrochemical sensing property of Mn doped V2O5 nanoparticles

International Nuclear Information System (INIS)

Suresh, R.; Giribabu, K.; Manigandan, R.; Narayanan, V.; Vijayalakshmi, L.; Stephen, A.

2012-01-01

In this study, pure V 2 O 5 and Mn doped V 2 O 5 nanoparticles were synthesized by thermal decomposition method. The FT-IR spectrum of Mn doped V 2 O 5 shows the bands at 822 and 1027 cm -1 which essentiaIIy of crystalline V 2 O 5 . Further, the bands observed in Mn doped V 2 O 5 are all shifted to lower wave number than the V 2 O 5 . The optical property of the nanocomposite was studied using UV-Visible absorption spectroscopy. The XRD data also revealed that the Mn doped V 2 O 5 obtained had an orthorhombic structure. The diffraction peaks in Mn doped V 2 O 5 nanoparticles are similar to that of V 2 O 5 . There was no indication of any other impurities in the sample. However, all the peaks of V 2 O 5 are slightly shifted to tower 2θ values. The FE-SEM image of V 2 O 5 shows that the particles adopt ellipse-like particles with different sizes due to aggregation. The synthesized nanoparticles were used to modify glassy carbon electrode (GCE) and the modified electrode was used to detect uric acid (UA) by voltammetric techniques. The effects of Mn on the optical, morphological and electrochemical detecting property of V 2 O 5 have also been studied. (author)

Dielectric Properties and Characterisation of Titanium Dioxide Obtained by Different Chemistry Methods

Directory of Open Access Journals (Sweden)

Aleksandra Wypych

2014-01-01

Full Text Available We made comparison of titanium dioxide powders obtained from three syntheses including sol-gel and precipitation methods as well as using layered (tetramethylammonium titanate as a source of TiO2. The obtained precursors were subjected to step annealing at elevated temperatures to transform into rutile form. The transformation was determined by Raman measurements in each case. The resulting products were characterised using Raman spectroscopy and dynamic light scattering. The main goal of the studies performed was to compare the temperature of the transformation in three titania precursors obtained by different methods of soft chemistry routes and to evaluate dielectric properties of rutile products by means of broadband dielectric spectroscopy. Different factors affecting the electrical properties of calcinated products were discussed. It was found that sol-gel synthesis provided rutile form after annealing at 850°C with the smallest particles size about 20 nm, the highest value of dielectric permittivity equal to 63.7, and loss tangent equal to 0.051 at MHz frequencies. The other powders transformed to rutile at higher temperature, that is, 900°C, exhibit lower value of dielectric permittivity and had a higher value of particles size. The correlation between the anatase-rutile transformation temperature and the size of annealed particles was proposed.

Evaluation of gamma-ray attenuation properties of bismuth borate glass systems using Monte Carlo method

Science.gov (United States)

Tarim, Urkiye Akar; Ozmutlu, Emin N.; Yalcin, Sezai; Gundogdu, Ozcan; Bradley, D. A.; Gurler, Orhan

2017-11-01

A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi2O3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experimental attenuation coefficients is presented.

Dielectric and magnetic properties of (Zn, Co) co-doped SnO2 nanoparticles

International Nuclear Information System (INIS)

Rajwali, Khan; Fang Ming-Hu

2015-01-01

Polycrystalline samples of (Zn, Co) co-doped SnO 2 nanoparticles were prepared using a co-precipitation method. The influence of (Zn, Co) co-doping on electrical, dielectric, and magnetic properties was studied. All of the (Zn, Co) co-doped SnO 2 powder samples have the same tetragonal structure of SnO 2 . A decrease in the dielectric constant was observed with the increase of Co doping concentration. It was found that the dielectric constant and dielectric loss values decrease, while AC electrical conductivity increases with doping concentration and frequency. Magnetization measurements revealed that the Co doping SnO 2 samples exhibits room temperature ferromagnetism. Our results illustrate that (Zn, Co) co-doped SnO 2 nanoparticles have an excellent dielectric, magnetic properties, and high electrical conductivity than those reported previously, indicating that these (Zn, Co) co-doped SnO 2 materials can be used in the field of the ultrahigh dielectric material, high frequency device, and spintronics. (paper)

Preparation and optical properties of AgGaS{sub 2} nanofilms

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jianjun [School of Materials Sci. and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Huang, Yi [School of Electronic and Information Engineering, Southwest University for Nationalities, Chengdu 610041 (China)

2011-05-15

In this paper, AgGaS{sub 2} nanofilms have been prepared by a two-step process involving the successive ionic layer absorption and reaction (SILAR) and annealing method. Using AgNO{sub 3}, GaCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} as reaction sources, the mixture films were firstly deposited on quartz glass substrates at room temperature, and then annealed in Ar environment at 200-500 C for 4 h, respectively. The effects of annealing temperature on structural and optical properties were investigated by XRD, UV-Vis, EDS and photoluminescence (PL) spectra. It was revealed in XRD results that {alpha}-Ag{sub 9}GaS{sub 6} was contained in the samples annealed at 200 C, and this phase was decreased with increase of the annealing temperatures. When the sample was annealed at above 400 C, the chalcopyrite AgGaS{sub 2} nanofilm was obtained. The preferred orientation was exhibited along the (112) plane. It was shown in atomic force microscopy (AFM) results that the grain sizes in AgGaS{sub 2} nanofilms were 18-24 nm and the thin films were smooth and strongly adherent to the substrates. When the annealing temperature was higher than 400 C, it is an optimum condition to improve the structural and optical properties of the AgGaS{sub 2} thin films. The room temperature PL spectra of AgGaS{sub 2} nanofilms showed prominent band edge emission at 2.72 eV. Based on all results mentioned above, it can be concluded that the SILAR-annealing method is preferable to preparing high-quality AgGaS{sub 2} nanofilms. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Thermoelectric properties of Al doped Mg{sub 2}Si material

Energy Technology Data Exchange (ETDEWEB)

Kaur, Kulwinder, E-mail: kulwindercmp@gmail.com; Kumar, Ranjan [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Rani, Anita [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Guru Nanak College for Girls, Sri Muktsar Sahib, Punjab (India)

2015-08-28

In the present paper we have calculated thermoelectric properties of Al doped Mg{sub 2}Si material (Mg{sub 2−x}Al{sub x}Si, x=0.06) using Pseudo potential plane wave method based on DFT and Semi classical Boltzmann theory. The calculations showed n-type conduction, indicating that the electrical conduction are due to electron. The electrical conductivity increasing with increasing temperature and the negative value of Seebeck Coefficient also show that the conduction is due to electron. The thermal conductivity was increased slightly by Al doping with increasing temperature due to the much larger contribution of lattice thermal conductivity over electronic thermal conductivity.

The properties of metal contacts on TiO2 thin films produced by reactive magnetron sputtering

Directory of Open Access Journals (Sweden)

Brus V. V.

2010-10-01

Full Text Available The article deals with research on volt-ampere characteristics of metal contacts (Al, Cr, In, Mo, Ti on titanium dioxide thin films and influence of annealing in vacuum on their electric properties. Volt-ampere characteristics measurements were taken by three-probe method. There was established that indium contact on TiO2 thin films possessed sharply defined ohmic properties.

Evaluation of gamma-ray attenuation properties of bismuth borate glass systems using Monte Carlo method

International Nuclear Information System (INIS)

Tarim, Urkiye Akar; Ozmutlu, Emin N.; Yalcin, Sezai; Gundogdu, Ozcan; Bradley, D.A.; Gurler, Orhan

2017-01-01

A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi 2 O 3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experimental attenuation coefficients is presented. - Highlights: • Radiation shielding properties of bismuth borate glass systems have been reported. • Mass attenuation coefficients increase linearly with increase in Bi concentration. • Half-value layer decreases with increasing concentration of Bi. • Half-value layer decreases with the increase in the sample density.

Growth, structure, Hirshfeld surface and spectroscopic properties of 2-amino-4-hydroxy-6-methylpyrimidinium-2,3-pyrazinedicorboxylate single crystal

Science.gov (United States)

Faizan, Mohd; Alam, Mohammad Jane; Afroz, Ziya; Rodrigues, Vítor Hugo Nunes; Ahmad, Shabbir

2018-03-01

The present work is focused on the crystal structure, vibrational spectroscopy and DFT calculations of hydrogen bonded 2,3-pyrazinedicorboxylic acid and 2-amino-4-hydroxy-6-methylpyrimidine (PDCA-.AHMP+) crystal. The crystal structure has been determined using single crystal X-ray diffraction analysis which shows that the crystal belongs to monoclinic space group P21/n. The PDCA-.AHMP+ crystal has been characterized by FTIR, FT-Raman and FT-NMR spectroscopic techniques. The FTIR and FT-Raman spectra of the complex have unique spectroscopic feature as compared with those of the starting material to confirm salt formation. The theoretical vibrational studies have been performed to understand the modes of the vibrations of asymmetric unit of the complex by DFT methods. Hirschfeld surface and 2D fingerprint plots analyses were carried out to investigate the intermolecular interactions and its contribution in the building of PDCA-.AHMP+ crystal. The experimental and simulated 13C and 1H NMR studies have assisted in structural analysis of PDCA-.AHMP+ crystal. The electronic spectroscopic properties of the complex were explored by the experimental as well as theoretical electronic spectra simulated using TD-DFT/IEF-PCM method at B3LYP/6-311++G (d,p) level of theory. In addition, frontier molecular orbitals, molecular electrostatic potential map (MEP) and nonlinear optical (NLO) properties using DFT method have been also presented.

Analysis of simplified heat transfer models for thermal property determination of nano-film by TDTR method

Science.gov (United States)

Wang, Xinwei; Chen, Zhe; Sun, Fangyuan; Zhang, Hang; Jiang, Yuyan; Tang, Dawei

2018-03-01

Heat transfer in nanostructures is of critical importance for a wide range of applications such as functional materials and thermal management of electronics. Time-domain thermoreflectance (TDTR) has been proved to be a reliable measurement technique for the thermal property determinations of nanoscale structures. However, it is difficult to determine more than three thermal properties at the same time. Heat transfer model simplifications can reduce the fitting variables and provide an alternative way for thermal property determination. In this paper, two simplified models are investigated and analyzed by the transform matrix method and simulations. TDTR measurements are performed on Al-SiO2-Si samples with different SiO2 thickness. Both theoretical and experimental results show that the simplified tri-layer model (STM) is reliable and suitable for thin film samples with a wide range of thickness. Furthermore, the STM can also extract the intrinsic thermal conductivity and interfacial thermal resistance from serial samples with different thickness.

Effect of Gas Pressure and Temperature on Stereometric Properties of Al+Al2O3 Composite Coatings Deposited by LPCS Method

Directory of Open Access Journals (Sweden)

Winnicki M.

2014-10-01

Full Text Available The paper deals with effect of working gas pressure and temperature on surface stereometry of coatings deposited by low-pressure cold spray method. Examinations were focused on aluminium coatings which are commonly used to protect substrate against corrosion. A commercial Al spherical feedstock powder with admixture of Al2O3 (Al + 60vol.-% Al2O3, granulation -50+10 µm, was used to coat steel, grade S235JR. Thedeposited coatings were studied to determine their stereometry, i.e. roughness, transverse and longitudinal waviness, topography of surface and thickness as the functions of gas pressure and temperature. A profilometer and focal microscope were used to evaluate the stereometric properties. In order to reduce the number of variables, the remaining process parameters, i.e. shape and size of de Laval nozzle, nozzle-to-substrate distance, powder mass flow rate, linear velocity of spraying gun, were kept unchanged. The investigation confirmed influence of temperature and pressure on coating thickness as well as on the surface seterometry.

Physicochemical properties and transport of steroids across Caco-2 cells

NARCIS (Netherlands)

Faassen, F.; Kelder, J.; Lenders, J.; Onderwater, R.; Vromans, H.

2003-01-01

Purpose. The purpose of this work was to study the relevant physicochemical properties for the absorption of steroids. Methods. Various physicochemical properties of steroids were calculated (molecular weight, ClogP, static polar surface area [PSA], etc.). Within this series of steroids, different

Investigation of TL, OSL and PTTL properties of Mg2SiO4:Tb dosimeters

International Nuclear Information System (INIS)

Oguz, K. F.; Goekce, M.; Karali, T.; Harmansah, C.

2010-01-01

In this study thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of Mg 2 SiO 4 :Tb in the form of sintered pellets were investigated. Mg 2 SiO 4 :Tb is a recently developed dosimetric material which offers high sensitivity for TL and OSL in dosimetric applications. Thermoluminescence glow curve of Tb doped Mg 2 SiO 4 samples show a glow peak at about 200 degree Celsius with two small peaks at about 275 and 330 degree Celsius, respectively. OSL experiments showed that blue light (470 nm) is six times more efficient than green light (532 nm) to stimulate the OSL emission. The aim of this study was to determine the TL and OSL fading properties of Mg 2 SiO 4 : Tb using OSL and TL methods. In addition, PTTL properties of the Mg 2 SiO 4 : Tb was investigated by using blue LEDs, UV lamp and blue laser. Investigations on the fading properties also showed that the TL signal fades % 10 in a period of 1 month and OSL signal fades % 10 in a period of 3 month, which then the signal remains relatively stable for longer periods.

Fabrication and Piezoelectric Properties of Textured (Bi1/2K1/2)TiO3 Ferroelectric Ceramics

Science.gov (United States)

Nagata, Hajime; Saitoh, Masahiro; Hiruma, Yuji; Takenaka, Tadashi

2010-09-01

Textured (Bi1/2K1/2)TiO3 (BKT) ceramics were prepared by a reactive templated grain growth (RTGG) method to improve their piezoelectric properties. Also, a hot-pressing (HP) method was modified on the basis of RTGG method to obtain dense ceramics and promote the grain orientation. The textured BKT ceramics prepared by the RTGG and HP methods exhibited a relatively high orientation factor F of 0.82 and a high density ratio of 95-99%. Scanning electron microscopy (SEM) micrographs of the textured HP-BKT indicated a textured and poreless microstructure. In addition, the resistivity of the textured HP-BKT was 1.73×1013 Ω·cm. The piezoelectric strain constant d33 determined by means of resonance and antiresonance method was 125 pC/N for the direction parallel to the sheet-stacking direction of the RTGG process. From the measurement of field-induced stain, the normalized d33* (=Smax/Emax) at 80 kV/cm were 127 and 238 pm/V on the randomly oriented and textured samples (F=0.82) for the (∥) direction, respectively.

Computational study of structural, elastic and electronic properties of lithium disilicate (Li(2)Si(2)O(5)) glass-ceramic.

Science.gov (United States)

Biskri, Zine Elabidine; Rached, Habib; Bouchear, Merzoug; Rached, Djamel

2014-04-01

The objective of this study is to investigate theoretically the structural, elastic and electronic properties of Lithium Disilicate (LD) crystal (Li2Si2O5), using the pseudo potential method based on Density Functional Theory (DFT) with the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). The calculated structural properties namely the equilibrium lattice parameters and cell volume are in good agreement with the available experimental results. However, for the LD crystal elastic moduli: Shear modulus G, Young's modulus E and Poisson's ratio ν we have found a discrepancy between our theoretical values and experimental ones reported in polycrystalline sample containing LD crystals. The calculated elastic properties show that LD is more rigid compared with other components. We also investigated the mechanical stability of Li2Si2O5 compound and we have noticed that this compound is stable against elastic deformations. On the basis of shear to bulk modulus ratio analysis, we inferred that Li2Si2O5 compound is brittle in nature. In order to complete the fundamental characteristics of this compound we have measured the elastic anisotropy. Our results for the energy band structure and Density of States (DOS) show that Li2Si2O5 compound has an insulator characteristic. Copyright © 2013 Elsevier Ltd. All rights reserved.

OBTAINING AND PROPERTIES OF AgInS2 FILMS

Directory of Open Access Journals (Sweden)

M. A. Abdullaev

2016-01-01

Full Text Available Aim. The aim is to obtain AgInS2 films and study their electrical and optical properties.Methods. The samples of thin AgInS2 films for measurement were obtained by the method of magnetron sputtering with direct current. The structure, phase and elemental composition were studied using DRON-2 X-ray diffractometer (СuKа - radiation and the microscope LEO-1450 with EDS attachment for X-ray microanalysis. The optical transmittance and absorption were examined using MDR-2 monochromator in the wavelength range of 400-800 nm with the Keitley electrometer and FD-10G; we applied the spectral resolution of ± 1 meV. The electrical conductivity, Hall effect was measured by the four-point probe method with indium ohmic contacts. Measurements were carried out in the temperature range of 77-400 K.Findings. We obtained indium disulfide and silver films with the thickness of up to 1 μm on quartz substrates by magnetron sputtering. It is shown that increasing the substrate temperature to about 450 0С allows to obtain single phase film with a chalcopyrite structure with a band gap of 1.88 eV and high absorption coefficient (>104см-1.Conclusions. The possibility of obtaining films in a wide range of the electrical resistance and variation of the electrical parameters at constant stoichiometry is of interest for efficient technologies of phototransduction.

A 2D/1D coupling neutron transport method based on the matrix MOC and NEM methods

International Nuclear Information System (INIS)

Zhang, H.; Zheng, Y.; Wu, H.; Cao, L.

2013-01-01

A new 2D/1D coupling method based on the matrix MOC method (MMOC) and nodal expansion method (NEM) is proposed for solving the three-dimensional heterogeneous neutron transport problem. The MMOC method, used for radial two-dimensional calculation, constructs a response matrix between source and flux with only one sweep and then solves the linear system by using the restarted GMRES algorithm instead of the traditional trajectory sweeping process during within-group iteration for angular flux update. Long characteristics are generated by using the customization of commercial software AutoCAD. A one-dimensional diffusion calculation is carried out in the axial direction by employing the NEM method. The 2D and ID solutions are coupled through the transverse leakage items. The 3D CMFD method is used to ensure the global neutron balance and adjust the different convergence properties of the radial and axial solvers. A computational code is developed based on these theories. Two benchmarks are calculated to verify the coupling method and the code. It is observed that the corresponding numerical results agree well with references, which indicates that the new method is capable of solving the 3D heterogeneous neutron transport problem directly. (authors)

A 2D/1D coupling neutron transport method based on the matrix MOC and NEM methods

Energy Technology Data Exchange (ETDEWEB)

Zhang, H.; Zheng, Y.; Wu, H.; Cao, L. [School of Nuclear Science and Technology, Xi' an Jiaotong University, No. 28, Xianning West Road, Xi' an, Shaanxi 710049 (China)

2013-07-01

A new 2D/1D coupling method based on the matrix MOC method (MMOC) and nodal expansion method (NEM) is proposed for solving the three-dimensional heterogeneous neutron transport problem. The MMOC method, used for radial two-dimensional calculation, constructs a response matrix between source and flux with only one sweep and then solves the linear system by using the restarted GMRES algorithm instead of the traditional trajectory sweeping process during within-group iteration for angular flux update. Long characteristics are generated by using the customization of commercial software AutoCAD. A one-dimensional diffusion calculation is carried out in the axial direction by employing the NEM method. The 2D and ID solutions are coupled through the transverse leakage items. The 3D CMFD method is used to ensure the global neutron balance and adjust the different convergence properties of the radial and axial solvers. A computational code is developed based on these theories. Two benchmarks are calculated to verify the coupling method and the code. It is observed that the corresponding numerical results agree well with references, which indicates that the new method is capable of solving the 3D heterogeneous neutron transport problem directly. (authors)

Production of various sizes and some properties of beryllium pebbles by the rotating electrode method

Energy Technology Data Exchange (ETDEWEB)

Iwadachi, T.; Sakamoto, N.; Nishida, K. [NGK Insulators Ltd., Nagoya (Japan); Kawamura, H.

1998-01-01

The particle size distribution of beryllium pebbles produced by the rotating electrode method was investigated. Particle size depends on some physical properties and process parameters, which can practicaly be controlled by varying electrode angular velocities. The average particle sizes produced were expressed by the hyperbolic function with electrode angular velocity. Particles within the range of 0.3 and 2.0 mm in diameter are readily produced by the rotating electrode method while those of 0.2 mm in diameter are also fabricable. Sphericity and surface roughness were good in each size of pebble. Grain sizes of the pebbles are 17 {mu} m in 0.25 mm diameter pebbles and 260 {mu} m in 1.8 mm diameter pebbles. (author)

Surface-defect induced modifications in the optical properties of α-MnO_2 nanorods

International Nuclear Information System (INIS)

John, Reenu Elizabeth; Chandran, Anoop; Thomas, Marykutty; Jose, Joshy; George, K.C.

2016-01-01

Graphical abstract: - Highlights: • Alpha-MnO_2 nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO_2 nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO_6 octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn"3"+) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO_2. These studies suggest that

Estimation of Physical Properties of Amino Acids by Group-Contribution Method

DEFF Research Database (Denmark)

Jhamb, Spardha Virendra; Liang, Xiaodong; Gani, Rafiqul

2018-01-01

In this paper, we present group-contribution (GC) based property models for estimation of physical properties of amino acids using their molecular structural information. The physical properties modelled in this work are normal melting point (Tm), aqueous solubility (Ws), and octanol....../water partition coefficient (Kow) of amino acids. The developed GC-models are based on the published GC-method by Marrero and Gani (J. Marrero, R. Gani, Fluid Phase Equilib. 2001, 183-184, 183-208) with inclusion of new structural parameters (groups and molecular weight of compounds). The main objective...... of introducing these new structural parameters in the GC-model is to provide additional structural information for amino acids having large and complex structures and thereby improve predictions of physical properties of amino acids. The group-contribution values were calculated by regression analysis using...

Aminopropyl-Functionalized Silica CO2 Adsorbents via Sonochemical Methods

Directory of Open Access Journals (Sweden)

Gregory P. Knowles

2016-01-01

Full Text Available Aminopropyl-functionalized hexagonal mesoporous silica (HMS products, as are of interest for CO2 capture applications, were separately prepared by mixing aminopropyltrimethoxysilane (APTS and HMS in toluene via a conventional stirred reactor and via sonication assisted methods, to investigate the potential of sonication to facilitate the preparation of products with higher tether loadings and correspondingly higher CO2 sorption capacities. Sonication was expected to improve both the dispersion of the substrate in the solvent and the diffusion of the silane throughout the mesoporous substrate. Structural properties of the products were determined by X-ray diffraction, N2 adsorption/desorption (77 K, helium pycnometry, and elemental analysis, and CO2 adsorption/desorption properties were determined via thermogravimetric and differential thermal analysis. The tether loadings of the sonication products (up to 1.8 tethers·nm−2 were found to increase with sonication time and in each case were greater than the corresponding product prepared by the conventional approach. It was also found that the concentration of the reagent mixture influenced the extent of functionalization, that the crude products cured effectively under N2 flow as under vacuum, and that rinsing the crude products prior to curing was not essential. Sonication products with higher tether loadings were found to exhibit higher CO2 sorption capacities as expected.

An improved method to determine neuromuscular properties using force laws - From single muscle to applications in human movements.

Science.gov (United States)

Siebert, T; Sust, M; Thaller, S; Tilp, M; Wagner, H

2007-04-01

We evaluate an improved method for individually determining neuromuscular properties in vivo. The method is based on Hill's equation used as a force law combined with Newton's equation of motion. To ensure the range of validity of Hill's equation, we first perform detailed investigations on in vitro single muscles. The force-velocity relation determined with the model coincides well with results obtained by standard methods (r=.99) above 20% of the isometric force. In addition, the model-predicted force curves during work loop contractions very well agree with measurements (mean difference: 2-3%). Subsequently, we deduce theoretically under which conditions it is possible to combine several muscles of the human body to model muscles. This leads to a model equation for human leg extension movements containing parameters for the muscle properties and for the activation. To numerically determine these invariant neuromuscular properties we devise an experimental method based on concentric and isometric leg extensions. With this method we determine individual muscle parameters from experiments such that the simulated curves agree well with experiments (r=.99). A reliability test with 12 participants revealed correlations r=.72-.91 for the neuromuscular parameters (p<.01). Predictions of similar movements under different conditions show mean errors of about 5%. In addition, we present applications in sports practise and theory.

Preparation and Properties of Paraffin/TiO2/Active-carbon Composite Phase Change Materials

Directory of Open Access Journals (Sweden)

HAO Yong-gan

2016-11-01

Full Text Available A novel composite phase change materials (PCMs of paraffin/TiO2/active-carbon was prepared by a microemulsion method, where paraffin acted as a PCM and titanium dioxide (TiO2 as matrix material, and a small amount of active carbon was added to improve the thermal conductivity. The compositions, morphology and thermal properties of the paraffin/TiO2/active-carbon composite PCMs were characterized by XRD, SEM, TGA and DSC respectively. The shape stability during phase change process of this composite was also tested. The results show that paraffin is well encapsulated by TiO2 matrix, and thus exhibiting excellent shape-stabilized phase change feature. Besides, this composite PCM also presents superhydrophobic property. Therefore, these multifunctional features will endow PCMs with important application potential in energy efficient buildings.

Improvement of the bio-functional properties of TiO{sub 2} nanotubes

Energy Technology Data Exchange (ETDEWEB)

Roguska, A. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Pisarek, M., E-mail: mpisarek@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Belcarz, A. [Chair and Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Marcon, L. [Interdisciplinary Research Institute, USR CNRS 3078 Parc de la Haute Borne, 50 av. de Halley 59658 Villeneuve d’Ascq (France); Holdynski, M. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Andrzejczuk, M. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Janik-Czachor, M. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

2016-12-01

Highlights: • The methods of biofunctional properties improvement of TiO{sub 2} nanotubes are proposed. • The increase of TiO{sub 2} nanotubes diameter promotes the U2OS cell proliferation. • Calcium phosphate coating deposited TiO{sub 2} nanotube layer promotes the cell growth. • Deposition of Ag nanoparticles inhibits the survivability of S. epidermidis cells. - Abstract: Titanium oxide nanotubes with diameters from ca. 40–120 nm fabricated by the anodic oxidation of Ti at a constant voltage (10–28 V) were investigated to identify factors improving their bio-functional properties. Prepared substrates were subsequently annealed at 450 °C and 650 °C to obtain nanotubes having a crystalline structure, and were then examined by SEM, XRD, XPS, BET and contact angle measurement techniques. The thermally stabilized surfaces were subjected to bidirectional functionalization: by deposition of a thin layer of Ca-P and by loading with silver nanoparticles. Three factors were found to promote the proliferation of osteoblast (U2OS) cells: a larger nanotube diameter, a higher annealing temperature, and the presence of a thin Ca-P layer. Differentiation of these cells (by ALP test) was stimulated by a higher (650 °C) nanotube annealing temperature, but not by a thin Ca-P layer. The TiO{sub 2} nanotubes-modified samples exhibited noticeable antibacterial properties. Moreover, the additional deposition of Ag nanoparticles almost completely inhibited the survivability of S. epidermidis cells beyond 3 h of contact. In conclusion, TiO{sub 2} nanotubes-modified surfaces exhibit distinct bone forming ability and significant antibacterial properties, and can be easily functionalized by a thin Ca-P layer or nano-Ag deposition for further improvement of the above functionalities.

Differentiability properties of the efficient (u,q2)-set in the Markowitz portfolio selection method

NARCIS (Netherlands)

Kriens, J.; Strijbosch, L.W.G.; Vörös, J.

1994-01-01

The set of efficient (Rho2)-combinations in the (Rho2)-plane of the Markowitz portfolio selection method consists of a series of strictly convex parabola. In the transition points from one parabola to the next one, the curve may be indifferentiable. The article gives necessary and sufficient

26 CFR 1.48-2 - New section 38 property.

Science.gov (United States)

2010-04-01

... Computing Credit for Investment in Certain Depreciable Property § 1.48-2 New section 38 property. (a) In... shall be taken into account as the basis of new section 38 property in determining qualified investment... taken into account by the taxpayer in computing qualified investment in new section 38 property. Example...

EVALUATION OF METHODS FOR ESTIMATING FATIGUE PROPERTIES APPLIED TO STAINLESS STEELS AND ALUMINUM ALLOYS

Directory of Open Access Journals (Sweden)

Taylor Mac Intyer Fonseca Junior

2013-12-01

Full Text Available This work evaluate seven estimation methods of fatigue properties applied to stainless steels and aluminum alloys. Experimental strain-life curves are compared to the estimations obtained by each method. After applying seven different estimation methods at 14 material conditions, it was found that fatigue life can be estimated with good accuracy only by the Bäumel-Seeger method for the martensitic stainless steel tempered between 300°C and 500°C. The differences between mechanical behavior during monotonic and cyclic loading are probably the reason for the absence of a reliable method for estimation of fatigue behavior from monotonic properties for a group of materials.

Magnetic Properties of NdAl2

DEFF Research Database (Denmark)

Bak, P.

1974-01-01

The magnetic properties of NdAl2 are calculated using a Hamiltonian including crystal-field and isotropic exchange interaction terms. A two-dimensional mean-field theory is evaluated to calculate single-crystal magnetization curves. It is shown that the magnetic properties can be understood using...... the crystal-field parameters derived from the magnetic exciton spectrum measured by Houmann et al. by means of inelastic neutron scattering. The combined lambda -Schottky anomaly in the heat capacity is explained. No additional parameters are introduced....

A Review on Synthesis of Nano-TiO2 via Different Methods

Directory of Open Access Journals (Sweden)

M. Malekshahi Byranvand

2013-03-01

Full Text Available Titanium dioxide is one kind of important materials, which has been extensively investigated because of its unique electronic and optical properties. A large number of efforts have been made to synthesize TiO2 materials with different methods. In this review paper, we summarize the synthesis pathways, morphology, as well as crystallization of the nanostructured TiO2. In addition, we also mention several nanostructured TiO2 materials.

Hydrothermal Synthesis and Electrochemical Properties of Spherical α-MnO2 for Supercapacitors.

Science.gov (United States)

Chen, Ya; Qin, Wenqing; Fan, Ruijuan; Wang, Jiawei; Chen, Baizhen

2015-12-01

In the present work, spherical α-MnO2 with a high specific capacitance was synthesized by a two-step hydrothermal route. MnCO3 precursors were first prepared by a common hydrothermal method, and then converted to α-MnO2 via a hydrothermal reaction between the precursors and KMnO4 solutions. The effects of hydrothermal temperature on the morphology, crystal structure and specific area of the MnO2 were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET measurements. The electrochemical capacitive properties of the manganese dioxides with different morphologies and structures were evaluated by cyclic voltammetry and galvonostatic charge-discharge tests. The results showed that the temperature in the second hydrothermal step had prominent impact on the capacitive properties of a-MnO2. The MnO2 synthesized at 150 *C exhibited a highest specific capacitance of 328.4 Fx g(-1) at a charge-discharge current density of 100 mA x g(-1).

Hydrogen desorption properties of MgH2–Ni–Ni2Si composites prepared by mechanochemical method

International Nuclear Information System (INIS)

Shimada, Motoki; Higuchi, Eiji; Inoue, Hiroshi

2013-01-01

Highlights: ► The MgH 2 –Ni composite showed fast hydrogen desorption rate at 250 °C. ► The MgH 2 –Ni–Ni 2 Si composite showed fast hydrogen desorption rate at 220 °C. ► Nanocrystalline Mg 2 Ni and Mg 2 Si were formed between Mg and adjacent Ni or Si. ► Ni 2 Si did not form any alloys and work as a catalyst. -- Abstract: To improve hydrogen desorbability of Mg, some composites were prepared from MgH 2 , Ni and Ni 2 Si mixed powders by the mechanochemical method. The MgH 2 –Ni(2 mol%)–Ni 2 Si(1 mol%) composite was slower in hydrogen desorption rate at 250 °C than the MgH 2 –Ni(2 mol%) composite, while the hydrogen desorption rate at 220 °C for the former was faster than that for the latter. The XRD pattern of the MgH 2 –Ni(2 mol%) composite showed that after hydrogen desorption at 400 °C small diffraction peaks assigned to Mg 2 Ni were observed with peaks assigned to Mg. They shifted to smaller angles after hydrogen absorption at 250 °C and come back to the original positions after hydrogen desorption at 250 °C, suggesting reversible hydrogen absorption/desorption of Mg 2 Ni. In contrast, Ni 2 Si was not changed over the whole processes. These results indicated that Ni 2 Si worked as a catalyst for hydrogen desorption, leading to the improvement of desorbability at 220 °C

Calculations on nonlinear optical properties for large systems the elongation method

CERN Document Server

Gu, Feng Long; Springborg, Michael; Kirtman, Bernard

2014-01-01

For design purposes one needs to relate the structure of proposed materials to their NLO (nonlinear optical) and other properties, which is a situation where theoretical approaches can be very helpful in providing suggestions for candidate systems that subsequently can be synthesized and studied experimentally. This brief describes the quantum-mechanical treatment of the response to one or more external oscillating electric fields for molecular and macroscopic, crystalline systems. To calculate NLO properties of large systems, a linear scaling generalized elongation method for the efficient and accurate calculation is introduced. The reader should be aware that this treatment is particularly feasible for complicated three-dimensional and/or delocalized systems that are intractable when applied to conventional or other linear scaling methods.

Effect of Silver Doping on Transport Properties of Bi2Se3: AgxBi2Se3 and Bi2-xAgxSe3

Science.gov (United States)

Zhang, Min; Wei, Zhan-Tao

2018-03-01

Ag-doped Bi2Se3 with the formula AgxBi2Se3 and Bi2-xAgxSe3 were prepared and their electrical and magnetic transport properties have been investigated to study the influence of silver doping on transport properties of Bi2Se3 with different Ag-doped method. All samples exhibited metallic resistivity and the resistivity increased with increasing Ag concentration. The lattice parameter c of Ag-substituted and Ag-intercalated samples displays a contrary change as the Ag concentration increased. For the Ag-intercalated samples, both the resistance upturn were observed in the curves of temperature dependent of resistivity and temperature dependent of magnetoresistance, respectively, indicating that the enhanced surface effect was obtained in those samples. Monotonously, field-induced MR peaks around 200 K were also observed in those samples. Similar behaviors were not observed in the Ag-substituted samples.

Effect of Silver Doping on Transport Properties of Bi2Se3: AgxBi2Se3 and Bi2-xAgxSe3

Science.gov (United States)

Zhang, Min; Wei, Zhan-Tao

2018-05-01

Ag-doped Bi2Se3 with the formula AgxBi2Se3 and Bi2-xAgxSe3 were prepared and their electrical and magnetic transport properties have been investigated to study the influence of silver doping on transport properties of Bi2Se3 with different Ag-doped method. All samples exhibited metallic resistivity and the resistivity increased with increasing Ag concentration. The lattice parameter c of Ag-substituted and Ag-intercalated samples displays a contrary change as the Ag concentration increased. For the Ag-intercalated samples, both the resistance upturn were observed in the curves of temperature dependent of resistivity and temperature dependent of magnetoresistance, respectively, indicating that the enhanced surface effect was obtained in those samples. Monotonously, field-induced MR peaks around 200 K were also observed in those samples. Similar behaviors were not observed in the Ag-substituted samples.

Oscillator strengths, first-order properties, and nuclear gradients for local ADC(2)

Energy Technology Data Exchange (ETDEWEB)

Schütz, Martin, E-mail: martin.schuetz@chemie.uni-regensburg.de [Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany)

2015-06-07

We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.

Oscillator strengths, first-order properties, and nuclear gradients for local ADC(2).

Science.gov (United States)

Schütz, Martin

2015-06-07

We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.