WorldWideScience

Sample records for band materials progress

  1. Photonic band gap materials

    Science.gov (United States)

    Cassagne, D.

    Photonic band gap materials Photonic band gap materials are periodic dielectric structures that control the propagation of electromagnetic waves. We describe the plane wave method, which allows to calculate the band structures of photonic crystals. By symmetry analysis and a perturbative approach, we predict the appearance of the low energy photonic band gaps of hexagonal structures. We propose new two-dimensional structures called graphite and boron nitride. Using a transfer matrix method, we calculate the transmission of the graphite structure and we show the crucial role of the coupling with external modes. We study the appearance of allowed modes in the photonic band gap by the introduction of localized defects in the periodicity. Finally, we discuss the properties of opals formed by self-organized silica microspheres, which are very promising for the fabrication of three-dimensional photonic crystals. Les matériaux à bandes interdites photoniques sont des structures diélectriques périodiques qui contrôlent la propagation des ondes électromagnétiques. Nous décrivons la méthode des ondes planes qui permet de calculer les structures de bandes des cristaux photoniques. Par une analyse de la symétrie et une approche perturbative, nous précisons les conditions d'existence des bandes interdites de basse énergie. Nous proposons de nouvelles structures bidimensionnelles appelées graphite et nitrure de bore. Grâce à une méthode de matrices de transfert, nous calculons la transmission de la structure graphite et nous mettons en évidence le rôle fondamental du couplage avec les modes extérieurs. Nous étudions l'apparition de modes permis dans la bande interdite grâce à l'introduction de défauts dans la périodicité. Enfin, nous discutons les propriétés des opales constituées de micro-billes de silice auto-organisées, qui sont très prometteuses pour la fabrication de cristaux photoniques tridimensionnels.

  2. Band engineering of thermoelectric materials.

    Science.gov (United States)

    Pei, Yanzhong; Wang, Heng; Snyder, G J

    2012-12-01

    Lead chalcogenides have long been used for space-based and thermoelectric remote power generation applications, but recent discoveries have revealed a much greater potential for these materials. This renaissance of interest combined with the need for increased energy efficiency has led to active consideration of thermoelectrics for practical waste heat recovery systems-such as the conversion of car exhaust heat into electricity. The simple high symmetry NaCl-type cubic structure, leads to several properties desirable for thermoelectricity, such as high valley degeneracy for high electrical conductivity and phonon anharmonicity for low thermal conductivity. The rich capabilities for both band structure and microstructure engineering enable a variety of approaches for achieving high thermoelectric performance in lead chalcogenides. This Review focuses on manipulation of the electronic and atomic structural features which makes up the thermoelectric quality factor. While these strategies are well demonstrated in lead chalcogenides, the principles used are equally applicable to most good thermoelectric materials that could enable improvement of thermoelectric devices from niche applications into the mainstream of energy technologies.

  3. Intermediate-band silicon materials

    OpenAIRE

    Wahnón Benarroch, Perla; Palacios Clemente, Pablo; Conesa Cegarra, José Carlos

    2009-01-01

    [ES] Material de silicio de banda intermedia que comprende una variedad de silicio, tal como las de tipo clatrato, amorfo o nanoestructurado, cuyo ancho de banda prohibida, también llamado bandgap, está aumentado hasta alcanzar un valor en el rango entre 1.7 y 2.5 eV, yen el que la banda intermedia se forma mediante la inclusión intersticial o sustitucional, en dicha variedad de silicio, de elementos de transición ligeros, seleccionados de los grupos 4-11 de la tabla periódica, que a...

  4. Analysis of shear banding in twelve materials

    Science.gov (United States)

    Batra, R. C.; Kim, C. H.

    The problem of the initiation and growth of shear bands in 12 different materials, namely, OFHC copper, Cartridge brass, Nickel 200, Armco IF (interstitial free) iron, Carpenter electric iron, 1006 steel, 2024-T351 aluminum, 7039 aluminum, low alloy steel, S-7 tool steel, Tungsten alloy, and Depleted Uranium (DU -0.75 Ti) is studied with the objectives of finding out when a shear band initiates, and upon what parameters does the band width depend. The nonlinear coupled partial differential equations governing the overall simple shearing deformations of a thermally softening viscoplastic block are analyzed. It is assumed that the thermomechanical response of these materials can be adequately represented by the Johnson-Cook law, and the only inhomogeneity present in the block is the variation in its thickness. The effect of the defect size on the initiation and subsequent growth of the band is also studied. It is found that, for each one of these 12 materials, the deformation has become nonhomogeneous by the time the maximum shear stress occurs. Also the band width, computed when the shear stress has dropped to 85 percent of its peak value, does not correlate well with the thermal conductivity of the material. The band begins to grow rapidly when the shear stress has dropped to 90 percent of its maximum value.

  5. Optical band gaps of organic semiconductor materials

    Science.gov (United States)

    Costa, José C. S.; Taveira, Ricardo J. S.; Lima, Carlos F. R. A. C.; Mendes, Adélio; Santos, Luís M. N. B. F.

    2016-08-01

    UV-Vis can be used as an easy and forthright technique to accurately estimate the band gap energy of organic π-conjugated materials, widely used as thin films/composites in organic and hybrid electronic devices such as OLEDs, OPVs and OFETs. The electronic and optical properties, including HOMO-LUMO energy gaps of π-conjugated systems were evaluated by UV-Vis spectroscopy in CHCl3 solution for a large number of relevant π-conjugated systems: tris-8-hydroxyquinolinatos (Alq3, Gaq3, Inq3, Al(qNO2)3, Al(qCl)3, Al(qBr)3, In(qNO2)3, In(qCl)3 and In(qBr)3); triphenylamine derivatives (DDP, p-TTP, TPB, TPD, TDAB, m-MTDAB, NPB, α-NPD); oligoacenes (naphthalene, anthracene, tetracene and rubrene); oligothiophenes (α-2T, β-2T, α-3T, β-3T, α-4T and α-5T). Additionally, some electronic properties were also explored by quantum chemical calculations. The experimental UV-Vis data are in accordance with the DFT predictions and indicate that the band gap energies of the OSCs dissolved in CHCl3 solution are consistent with the values presented for thin films.

  6. Band Structure Characteristics of Nacreous Composite Materials with Various Defects

    Science.gov (United States)

    Yin, J.; Zhang, S.; Zhang, H. W.; Chen, B. S.

    2016-06-01

    Nacreous composite materials have excellent mechanical properties, such as high strength, high toughness, and wide phononic band gap. In order to research band structure characteristics of nacreous composite materials with various defects, supercell models with the Brick-and-Mortar microstructure are considered. An efficient multi-level substructure algorithm is employed to discuss the band structure. Furthermore, two common systems with point and line defects and varied material parameters are discussed. In addition, band structures concerning straight and deflected crack defects are calculated by changing the shear modulus of the mortar. Finally, the sensitivity of band structures to the random material distribution is presented by considering different volume ratios of the brick. The results reveal that the first band gap of a nacreous composite material is insensitive to defects under certain conditions. It will be of great value to the design and synthesis of new nacreous composite materials for better dynamic properties.

  7. Intermediate band solar cells: Recent progress and future directions

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Y., E-mail: okada@mbe.rcast.u-tokyo.ac.jp; Tamaki, R.; Farrell, D. J.; Yoshida, K.; Ahsan, N.; Shoji, Y.; Sogabe, T. [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Ekins-Daukes, N. J., E-mail: n.ekins-daukes@imperial.ac.uk; Yoshida, M.; Pusch, A.; Hess, O.; Phillips, C. C. [Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Kita, T. [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Guillemoles, J.-F. [Institute of Research and Development of Energy from Photovoltaics (IRDEP-CNRS), Chatou 78401 (France); NextPV, Joint RCAST-CNRS Laboratory, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-06-15

    Extensive literature and publications on intermediate band solar cells (IBSCs) are reviewed. A detailed discussion is given on the thermodynamics of solar energy conversion in IBSCs, the device physics, and the carrier dynamics processes with a particular emphasis on the two-step inter-subband absorption/recombination processes that are of paramount importance in a successful implementation high-efficiency IBSC. The experimental solar cell performance is further discussed, which has been recently demonstrated by using highly mismatched alloys and high-density quantum dot arrays and superlattice. IBSCs having widely different structures, materials, and spectral responses are also covered, as is the optimization of device parameters to achieve maximum performance.

  8. Band Gaps of an Amorphous Photonic Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Yi-Quan; FENG Zhi-Fang; HU Xiao-Yong; CHENG Bing-Ying; ZHANG Dao-Zhong

    2004-01-01

    @@ A new kind of amorphous photonic materials is presented. Both the simulated and experimental results show that although the disorder of the whole dielectric structure is strong, the amorphous photonic materials have two photonic gaps. This confirms that the short-range order is an essential factor for the formation of the photonic gaps.

  9. Progress in synthesizing functional nano materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ With the consistent investment, the research team directed by Prof. Yadong Li of Chemistry Department of Tsinghua University achieved new progress in synthesizing nano materials with specific functions. The research team led by Prof.

  10. Central Flyway Duck Banding project : Annual progress report 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Central Flyway Council (CFC) initiated a six year duck banding program in 1996 with emphasis on mallard banding in North Dakota, South Dakota, Montana, and...

  11. Spectral Band Selection for Urban Material Classification Using Hyperspectral Libraries

    Science.gov (United States)

    Le Bris, A.; Chehata, N.; Briottet, X.; Paparoditis, N.

    2016-06-01

    In urban areas, information concerning very high resolution land cover and especially material maps are necessary for several city modelling or monitoring applications. That is to say, knowledge concerning the roofing materials or the different kinds of ground areas is required. Airborne remote sensing techniques appear to be convenient for providing such information at a large scale. However, results obtained using most traditional processing methods based on usual red-green-blue-near infrared multispectral images remain limited for such applications. A possible way to improve classification results is to enhance the imagery spectral resolution using superspectral or hyperspectral sensors. In this study, it is intended to design a superspectral sensor dedicated to urban materials classification and this work particularly focused on the selection of the optimal spectral band subsets for such sensor. First, reflectance spectral signatures of urban materials were collected from 7 spectral libraires. Then, spectral optimization was performed using this data set. The band selection workflow included two steps, optimising first the number of spectral bands using an incremental method and then examining several possible optimised band subsets using a stochastic algorithm. The same wrapper relevance criterion relying on a confidence measure of Random Forests classifier was used at both steps. To cope with the limited number of available spectra for several classes, additional synthetic spectra were generated from the collection of reference spectra: intra-class variability was simulated by multiplying reference spectra by a random coefficient. At the end, selected band subsets were evaluated considering the classification quality reached using a rbf svm classifier. It was confirmed that a limited band subset was sufficient to classify common urban materials. The important contribution of bands from the Short Wave Infra-Red (SWIR) spectral domain (1000-2400 nm) to material

  12. A bespoke single-band Hubbard model material

    Science.gov (United States)

    Griffin, S. M.; Staar, P.; Schulthess, T. C.; Troyer, M.; Spaldin, N. A.

    2016-02-01

    The Hubbard model, which augments independent-electron band theory with a single parameter to describe electron-electron correlations, is widely regarded to be the "standard model" of condensed-matter physics. The model has been remarkably successful at addressing a range of correlation phenomena in solids, but it neglects many behaviors that occur in real materials, such as phonons, long-range interactions, and, in its simplest form, multiorbital effects. Here, we use ab initio electronic structure methods to design a material whose Hamiltonian matches as closely as possible that of the single-band Hubbard model. Our motivation is to compare the measured properties of our new material to those predicted by reliable theoretical solutions of the Hubbard model to determine the relevance of the model in the description of real materials. After identifying an appropriate crystal class and several appropriate chemistries, we use density-functional theory and dynamical mean-field theory to screen for the desired electronic band structure and metal-insulator transition. We then explore the most promising candidates for structural stability and suitability for doping, and we propose specific materials for subsequent synthesis. Finally, we identify a regime—that should manifest in our bespoke material—in which the single-band Hubbard model on a triangular lattice exhibits exotic d -wave superconductivity.

  13. Shear banding and yield stress in soft glassy materials

    NARCIS (Netherlands)

    P.C.F. Møller; S. Rodts; M.A.J. Michels; D. Bonn

    2008-01-01

    Shear localization is a generic feature of flows in yield stress fluids and soft glassy materials but is incompletely understood. In the classical picture of yield stress fluids, shear banding happens because of a stress heterogeneity. Using recent developments in magnetic resonance imaging velocime

  14. Progress in molecular precursors for electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Buhro, W.E. [Washington Univ., St. Louis, MO (United States)

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  15. [Band electronic structures and crystal packing forces: Progress report, July 1, 1989--December 13, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This report briefly summaries our research accomplishments made during the period of July 1, 1989 to December 13, 1991. A number of significant progresses were achieved in our studies of several different classes of low-dimensional solid state materials. On the basis of tight-binding band electronic structure calculations, we investigated the electronic properties of various organic conducting salts, cuprate superconductors, and transition-metal oxide and chalcogenide metals to find structure-property correlations governing of the physical properties of these low-dimensional materials. By employing a number of different quality basis sets, we also carried out extensive ab initio SCF-MO/MP2 calculations on model molecular systems to accurately describe the weak intermolecular contact interactions governing the structures of organic donor slats and molecular crystals. Our research efforts led to about 80 publications and two important computer programs.

  16. (Band electronic structures and crystal packing forces: Progress report, July 1, 1989--December 13, 1991)

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    This report briefly summaries our research accomplishments made during the period of July 1, 1989 to December 13, 1991. A number of significant progresses were achieved in our studies of several different classes of low-dimensional solid state materials. On the basis of tight-binding band electronic structure calculations, we investigated the electronic properties of various organic conducting salts, cuprate superconductors, and transition-metal oxide and chalcogenide metals to find structure-property correlations governing of the physical properties of these low-dimensional materials. By employing a number of different quality basis sets, we also carried out extensive ab initio SCF-MO/MP2 calculations on model molecular systems to accurately describe the weak intermolecular contact interactions governing the structures of organic donor slats and molecular crystals. Our research efforts led to about 80 publications and two important computer programs.

  17. Superconductivity between standard types: Multiband versus single-band materials

    Energy Technology Data Exchange (ETDEWEB)

    Vagov, A.; Shanenko, A. A.; Milošević, M. V.; Axt, V. M.; Vinokur, V. M.; Aguiar, J. Albino; Peeters, F. M.

    2016-05-06

    In the nearest vicinity of the critical temperature, types I and II of conventional single-band superconductors interchange at the Ginzburg-Landau parameter κ = 1/√2. At lower temperatures this point unfolds into a narrow but finite interval of κ’s, shaping an intertype (transitional) domain in the (κ,T ) plane. In the present work, based on the extended Ginzburg-Landau formalism, we show that the same picture of the two standard types with the transitional domain in between applies also to multiband superconductors. However, the intertype domain notably widens in the presence of multiple bands and can become extremely large when the system has a significant disparity between the band parameters. It is concluded that many multiband superconductors, such as recently discovered borides and iron-based materials, can belong to the intertype regime.

  18. On acoustic band gaps in homogenized piezoelectric phononic materials

    Directory of Open Access Journals (Sweden)

    Rohan E.

    2010-07-01

    Full Text Available We consider a composite medium made of weakly piezoelectric inclusions periodically distributed in the matrix which ismade of a different piezoelectricmaterial. Themediumis subject to a periodic excitation with an incidence wave frequency independent of scale ε of the microscopic heterogeneities. Two-scale method of homogenization is applied to obtain the limit homogenized model which describes acoustic wave propagation in the piezoelectric medium when ε → 0. In analogy with the purely elastic composite, the resulting model allows existence of the acoustic band gaps. These are identified for certain frequency ranges whenever the so-called homogenized mass becomes negative. The homogenized model can be used for band gap prediction and for dispersion analysis for low wave numbers. Modeling such composite materials seems to be perspective in the context of Smart Materials design.

  19. Photonic band gap materials: design, synthesis, and applications

    International Nuclear Information System (INIS)

    Full text: Unlike semiconductors which facilitate the coherent propagation of electrons, photonic band gap (PBG) materials execute their novel functions through the coherent localization of photons. I review and discuss our recent synthesis of a large scale three-dimensional silicon photonic crystal with a complete photonic band gap near 1.5 microns. When a PBG material is doped with impurity atoms which have an electronic transition that lies within the gap, spontaneous emission of light from the atom is inhibited. Inside the gap, the photon forms a bound state to the atom. Outside the gap, radiative dynamics in the colored vacuum is highly non Markovian. I discuss the influence of these memory effects on laser action. When spontaneous emission is absent, the next order radiative effect (resonance dipole dipole interaction between atoms) must be incorporated leading to anomalous nonlinear optical effects which occur at a much lower threshold than in ordinary vacuum. I describe the collective switching of two-level atoms near a photonic band edge, by external laser field, from a passive state to one exhibiting population inversion. This effect is forbidden in ordinary vacuum. However, in the context of a PBG material, this effect may be utilized for an all-optical transistor. Finally, I discuss the prospects for a phase sensitive, single atom quantum memory device, onto which information may be written by an external laser pulse

  20. Multi-component transparent conducting oxides: progress in materials modelling

    Science.gov (United States)

    Walsh, Aron; Da Silva, Juarez L. F.; Wei, Su-Huai

    2011-08-01

    Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on density functional theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n and (In2O3)m(Ga2O3)l(ZnO)n; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high performance of amorphous oxide semiconductors. On the basis of these advances, the challenge of the rational design of novel electroceramic materials is discussed.

  1. Photonic band gap materials: Technology, applications and challenges

    International Nuclear Information System (INIS)

    Last century has been the age of Artificial Materials. One material that stands out in this regard is the semiconductor. The revolution in electronic industry in the 20th century was made possible by the ability of semiconductors to microscopically manipulate the flow of electrons. Further advancement in the field made scientists suggest that the new millennium will be the age of photonics in which artificial materials will be synthesized to microscopically manipulate the flow of light. One of these will be Photonic Band Gap material (PBG). PBG are periodic dielectric structures that forbid propagation of electromagnetic waves in a certain frequency range. They are able to engineer most fundamental properties of electromagnetic waves such as the laws of refraction, diffraction, and emission of light from atoms. Such PBG material not only opens up variety of possible applications (in lasers, antennas, millimeter wave devices, efficient solar cells photo-catalytic processes, integrated optical communication etc.) but also give rise to new physics (cavity electrodynamics, localization, disorder, photon-number-state squeezing). Unlike electronic micro-cavity, optical waveguides in a PBG microchip can simultaneously conduct hundreds of wavelength channels of information in a three dimensional circuit path. In this article we have discussed some aspects of PBG materials and their unusual properties, which provided a foundation for novel practical applications ranging from clinical medicine to information technology. (author)

  2. Band structures of 4f and 5f materials studied by angle-resolved photoelectron spectroscopy

    Science.gov (United States)

    Fujimori, Shin-ichi

    2016-04-01

    Recent remarkable progress in angle-resolved photoelectron spectroscopy (ARPES) has enabled the direct observation of the band structures of 4f and 5f materials. In particular, ARPES with various light sources such as lasers (hν ∼ 7~\\text{eV} ) or high-energy synchrotron radiations (hν ≳ 400~\\text{eV} ) has shed light on the bulk band structures of strongly correlated materials with energy scales of a few millielectronvolts to several electronvolts. The purpose of this paper is to summarize the behaviors of 4f and 5f band structures of various rare-earth and actinide materials observed by modern ARPES techniques, and understand how they can be described using various theoretical frameworks. For 4f-electron materials, ARPES studies of \\text{Ce}M\\text{I}{{\\text{n}}5} (M=\\text{Rh} , \\text{Ir} , and \\text{Co} ) and \\text{YbR}{{\\text{h}}2}\\text{S}{{\\text{i}}2} with various incident photon energies are summarized. We demonstrate that their 4f electronic structures are essentially described within the framework of the periodic Anderson model, and that the band-structure calculation based on the local density approximation cannot explain their low-energy electronic structures. Meanwhile, electronic structures of 5f materials exhibit wide varieties ranging from itinerant to localized states. For itinerant \\text{U}~5f compounds such as \\text{UFeG}{{\\text{a}}5} , their electronic structures can be well-described by the band-structure calculation assuming that all \\text{U}~5f electrons are itinerant. In contrast, the band structures of localized \\text{U}~5f compounds such as \\text{UP}{{\\text{d}}3} and \\text{U}{{\\text{O}}2} are essentially explained by the localized model that treats \\text{U}~5f electrons as localized core states. In regards to heavy fermion \\text{U} -based compounds such as the hidden-order compound \\text{UR}{{\\text{u}}2}\\text{S}{{\\text{i}}2} , their electronic structures exhibit complex behaviors. Their overall band structures

  3. Research progress of Si-based germanium materials and devices

    Science.gov (United States)

    Buwen, Cheng; Cheng, Li; Zhi, Liu; Chunlai, Xue

    2016-08-01

    Si-based germanium is considered to be a promising platform for the integration of electronic and photonic devices due to its high carrier mobility, good optical properties, and compatibility with Si CMOS technology. However, some great challenges have to be confronted, such as: (1) the nature of indirect band gap of Ge; (2) the epitaxy of dislocation-free Ge layers on Si substrate; and (3) the immature technology for Ge devices. The aim of this paper is to give a review of the recent progress made in the field of epitaxy and optical properties of Ge heterostructures on Si substrate, as well as some key technologies on Ge devices. High crystal quality Ge epilayers, as well as Ge/SiGe multiple quantum wells with high Ge content, were successfully grown on Si substrate with a low-temperature Ge buffer layer. A local Ge condensation technique was proposed to prepare germanium-on-insulator (GOI) materials with high tensile strain for enhanced Ge direct band photoluminescence. The advances in formation of Ge n+p shallow junctions and the modulation of Schottky barrier height of metal/Ge contacts were a significant progress in Ge technology. Finally, the progress of Si-based Ge light emitters, photodetectors, and MOSFETs was briefly introduced. These results show that Si-based Ge heterostructure materials are promising for use in the next-generation of integrated circuits and optoelectronic circuits. Project supported in part by the National Natural Science Foundation (Nos. 61036003, 61435013) and the Major State Basic Research Development Program of China (No. 2013CB632103).

  4. Broad band spectroscopic ellipsometry for the characterization of photovoltaic materials

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Elfotouh, F.A.; Horner, G.S.; Coutts, T.J.; Wanlass, M.W. (Solar Energy Research Inst., Golden, CO (USA))

    1991-05-01

    The availability of commercial spectroscopic ellipsometers (SE) has been restricted to the UV-visible range from 250-900 nm. Although this is useful for many applications, it must be extended to the near IR region (up to 1700 nm) for the study of the optical behavior of most photovoltaic materials. This paper discusses the development of a broad band (300-1700 nm) SE which has been used to measure the optical characteristics of various materials. Among these are the polycrystalline thin film materials, CuInSe{sub 2} and CdTe (for which single crystal samples have also been investigated), and materials for high efficiency cascade solar cells including InP, InGaAs and InGaAsP. Most of these data are not presently available over such a wide spectral range. Experimentally, a rotating polarizer-fixed analyzer ellipsometer with an a.c. detection system has been developed for accurate measurement of psi and {Delta}, the relevant ellipsometric parameters, in the near IR. This approach has certain advantages over the rotating analyzer-fixed polarizer systems including reduced sensitivity to room light. The analytical methods include the use of a specially developed computer modeling program which gives psi and {Delta} for a given set of values related to the film thickness (which may be finite or zero) and to the optical properties of the substrate. (orig.).

  5. Electromagnetic Attenuation Characteristics of Microbial Materials in the Infrared Band.

    Science.gov (United States)

    Wang, Peng; Liu, Hongxia; Zhao, Yizheng; Gu, Youlin; Chen, Wei; Wang, Li; Li, Le; Zhao, Xinying; Lei, Wuhu; Hu, Yihua; Zheng, Zhiming

    2016-09-01

    In this study, seven microbial materials (entomogenous fungi Bb3088 mycelia, entomogenous fungi Bb3088 spores, entomogenous fungi Ma2677 mycelia, entomogenous fungi Ma2677 spores, Bacillus subtilis 8204, Staphylococcus aureus 6725, and Saccharomyces cerevisiae 1025) were used to measure electromagnetic (EM) signal extinction. They were subjected to light absorption and reflection measurements in the range of 4000-400 cm(-1) (2.5-25 µm) using Fourier transform infrared spectroscopy. The specular reflection spectrum method was used to calculate the real (n) and imaginary (k) parts of the complex refractive index. The complex refractive index with real part n and imaginary part k in the infrared band satisfies the following conditions n ≥ 1 and k ≥ 0. The mass extinction coefficient was calculated based on Mie theory. Entomogenous fungi Ma2677 spores and entomogenous fungi Bb3088 spores were selected as EM signal extinction materials in the smoke box test. The transmittances of entomogenous fungi Bb3088 spores and entomogenous fungi Ma2677 spores were 11.63% and 5.42%, and the mass extinction coefficients were 1.8337 m(2)/g and 1.227 m(2)/g. These results showed that entomogenous fungi Bb3088 spores and entomogenous fungi Ma2677 spores have higher extinction characteristics than other microbial materials. PMID:27581361

  6. FY2011 Annual Progress Report for Propulsion Materials

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Patrick B. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Schutte, Carol L. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Gibbs, Jerry L. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2011-12-01

    Annual Progress Report for Propulsion Materials focusing on enabling and innovative materials technologies that are critical in improving the efficiency of advanced engines by providing enabling materials support for combustion, hybrid, and power electronics development.

  7. Progress in dual-band dual-polarization shared-aperture SAR antennas

    Institute of Scientific and Technical Information of China (English)

    Shunshi ZHONG; Zhu SUN; Xiaorong TANG

    2009-01-01

    The progress in dual-band dual-polarization (DBDP) shared-aperture antennas for the synthetic aper-ture radar (SAR) application in the last decade is reviewed.Several designs of DBDP SAR antenna arrays are introduced with their main performances, then their comparison is summarized. In addition, some techniques enhancing DBDP antenna performances are presented.

  8. New materials for intermediate band photovoltaic cells. A theoretical and experimental approach

    OpenAIRE

    Wahnón Benarroch, Perla; Palacios Clemente, Pablo; Aguilera Bonet, Irene; Seminóvski Pérez, Yohanna; Conesa, Jose Carlos; Lucena, Raquel

    2010-01-01

    Density functional theory calculations of certain transition-metal doped semiconductors show a partially occupied relatively narrow band located between valence band and conduction band. These novel systems, containing the metallic band, are called intermediate-band materials. They have enhanced optoelectronic properties which allow an increase in solar energy conversion efficiency of conventional solar cells. We previously proposed III-V, chalcopyrite and sulfide derived compounds show...

  9. W-Band Transmission MeasurementS and X-Band Dielectric Properties Measurements for a Radome Material Sample

    Science.gov (United States)

    Cravey, Robin L.; Tiemsin, Pacita I.

    1997-01-01

    This paper describes measurements which were performed on a sample of radome material in the Electromagnetic Properties Measurements Laboratory (EPML). The purpose of the measurements described in this paper was to determine the one-way transmission loss through the flat panel of radome material for a frequency range of 84 to 94 GHz, for varying incidence angles. The panel, which was manufactured by Norton Performance Plastics Corporation, was provided to the EPML by TRW. The size of the panel is 40 in x 36 in x 0.422 in and consists of a foam material with one side coated with a smooth white coating (this side will be referred to as the front side). The dielectric properties of the foam material from the inside of the panel were also determined at X-band (8.2-12.4 GHz). The W-band free space measurements are presented first, followed by the X-band dielectric properties measurements.

  10. Analysis of compressive failure of layered materials by kink band broadening

    DEFF Research Database (Denmark)

    Jensen, Henrik Myhre

    1999-01-01

    Failure by steady state kink band broadening in uni-directional fibre composites or layered materials is analysed. An incremental scheme for calculation of kink band broadening stresses and lock-up conditions in the band for arbitrary material behaviour is presented. The method is illustrated...... by material data which are representative for polymer matrix composites for which experimental work exists. (C) 1999 Elsevier Science Ltd. All rights reserved....

  11. Materials Department annual progress report for 1993

    International Nuclear Information System (INIS)

    Selected activities of the Materials Department at Risoe National Laboratory during 1993 are described. The work is presented in three chapters: Materials Science, Materials Engineering and Materials Technology. A survey is given of the Department's participation in international collaboration and of its activities within education and training. Furthermore, the main figures outlining the funding and expenditure of the Department are given. Lists of staff members, visiting scientists, publications, lectures and poster presentations are included. (au) (220 refs.)

  12. Photonic band structures in one-dimensional photonic crystals containing Dirac materials

    International Nuclear Information System (INIS)

    We have investigated the band structures of one-dimensional photonic crystals (1DPCs) composed of Dirac materials and ordinary dielectric media. It is found that there exist an omnidirectional passing band and a kind of special band, which result from the interaction of the evanescent and propagating waves. Due to the interface effect and strong dispersion, the electromagnetic fields inside the special bands are strongly enhanced. It is also shown that the properties of these bands are invariant upon the lattice constant but sensitive to the resonant conditions

  13. On the unified view of the contribution of plastic strain to cyclic crack initiation: Impact of the progressive transformation of shear bands to persistent slip bands

    International Nuclear Information System (INIS)

    To examine the local conditions necessary to create cracks around cyclic slip bands, we studied the evolution of surface topography by atomic force microscopy and deformation localization by transmission electron microscopy for a wide structural variety (grain and precipitate sizes) in nickel-base alloys. We observed that the variance σ2 associated with height emergence of deformation bands correlated directly with the type of bands, i.e. shear bands (SBs) or persistent slip bands (PSBs). An increase in the diameter of shearing precipitates induced a progressive transformation of SBs to PSBs with a decrease in the variance σ2. Surface analyses showed that a critical value of the local irreversible plastic strain accumulated in the band (γirr,pl,loc) was necessary to for crack initiation. The value of γirr,pl,loc increased with a progressive transformation of SBs to PSBs and the increase in band thickness. This last parameter is an internal length scale that plays an important role in diffusion of vacancies in accordance with Repetto’s model of crack initiation

  14. The progress of nanocrystalline hydride electrode materials

    International Nuclear Information System (INIS)

    This paper reviews research at the Institute of Materials Science and Engineering, Poznan University of Technology, on the synthesis of nanocrystalline hydride electrode materials. Nanocrystalline materials have been synthesized by mechanical alloying (MA) followed by annealing. Examples of the materials include TiFe-, ZrV2-, LaNi5 and Mg2Ni-type phases. Details on the process used and the enhancement of properties due to the nanoscale structures are presented. The synthesized alloys were used as negative electrode materials for Ni-MH battery. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. For example, it was found that the respective replacement of Fe in TiFe by Ni and/or by Cr, Co, Mo improved not only the discharge capacity but also the cycle life of these electrodes. The hydrogen storage properties of nanocrystalline ZrV2- and LaNi5-type powders prepared by mechanical alloying and annealing show no big difference with those of melt casting (polycrystalline) alloys. On the other hand, a partial substitution of Mg by Mn or Al in Mg2Ni alloy leads to an increase in discharge capacity, at room temperature. Furthermore, the effect of the nickel and graphite coating on the structure of some nanocrystalline alloys and the electrodes characteristics were investigated. In the case of Mg2Ni-type alloy mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. The combination of a nanocrystalline TiFe-, ZrV2- and LaNi5-type hydride electrodes and a nickel positive electrode to form a Ni-MH battery, has been successful. (authors)

  15. Formation of shear band in a granular material during triaxial compression test

    OpenAIRE

    Grochowicz M.; Ã…Âukaszuk J.; Horabik J.

    2000-01-01

    Formation of shear band during triaxial compression test of a sample of granular material was investigated experimentally. A new method of displacement field fixation in the sample of granular material was proposed. The method allows to analyse of displacement distribution inside a sample of any course granular material. Thickness of the fully developed shear band obtained in the triaxial compression test of a mustard seed was found approximately 15 times bigger than the mean seed diameter.

  16. Progress in the materials science of silicene

    International Nuclear Information System (INIS)

    In its freestanding, yet hypothetical form, the Si counterpart of graphene called silicene is predicted to possess massless Dirac fermions and to exhibit an experimentally accessible quantum spin Hall effect. Such interesting electronic properties are not realized in two-dimensional (2D) Si honeycomb lattices prepared recently on metallic substrates where the crystal and hybrid electronic structures of these ‘epitaxial silicene’ phases are strongly influenced by the substrate, and thus different from those predicted for isolated 2D structures. While the realization of such low-dimensional Si π materials has hardly been imagined previously, it is evident that the materials science behind silicene remains challenging. In this contribution, we will review our recent results that lead to an enhanced understanding of epitaxial silicene formed on diboride thin films, and discuss the remaining challenges that must be addressed in order to turn Si 2D nanostructures into technologically interesting nanoelectronic materials. (focus issue review)

  17. Maximizing phononic band gaps in piezocomposite materials by means of topology optimization.

    Science.gov (United States)

    Vatanabe, Sandro L; Paulino, Glaucio H; Silva, Emílio C N

    2014-08-01

    Phononic crystals (PCs) can exhibit phononic band gaps within which sound and vibrations at certain frequencies do not propagate. In fact, PCs with large band gaps are of great interest for many applications, such as transducers, elastic/acoustic filters, noise control, and vibration shields. Previous work in the field concentrated on PCs made of elastic isotropic materials; however, band gaps can be enlarged by using non-isotropic materials, such as piezoelectric materials. Because the main property of PCs is the presence of band gaps, one possible way to design microstructures that have a desired band gap is through topology optimization. Thus in this work, the main objective is to maximize the width of absolute elastic wave band gaps in piezocomposite materials designed by means of topology optimization. For band gap calculation, the finite element analysis is implemented with Bloch-Floquet theory to solve the dynamic behavior of two-dimensional piezocomposite unit cells. Higher order frequency branches are investigated. The results demonstrate that tunable phononic band gaps in piezocomposite materials can be designed by means of the present methodology.

  18. Ultrawide low frequency band gap of phononic crystal in nacreous composite material

    Energy Technology Data Exchange (ETDEWEB)

    Yin, J.; Huang, J.; Zhang, S., E-mail: zhangs@dlut.edu.cn; Zhang, H.W.; Chen, B.S.

    2014-06-27

    The band structure of a nacreous composite material is studied by two proposed models, where an ultrawide low frequency band gap is observed. The first model (tension-shear chain model) with two phases including brick and mortar is investigated to describe the wave propagation in the nacreous composite material, and the dispersion relation is calculated by transfer matrix method and Bloch theorem. The results show that the frequency ranges of the pass bands are quite narrow, because a special tension-shear chain motion in the nacreous composite material is formed by some very slow modes. Furthermore, the second model (two-dimensional finite element model) is presented to investigate its band gap by a multi-level substructure scheme. Our findings will be of great value to the design and synthesis of vibration isolation materials in a wide and low frequency range. Finally, the transmission characteristics are calculated to verify the results. - Highlights: • A Brick-and-Mortar structure is used to discuss wave propagation through nacreous materials. • A 1D Bloch wave solution of nacreous materials with a tension-shear chain model is obtained. • The band structure and transmission characteristics of nacreous materials with the FE model are examined. • An ultrawide low frequency band gap is found in nacreous materials with both theory and FE model.

  19. Progress in material design for biomedical applications.

    Science.gov (United States)

    Tibbitt, Mark W; Rodell, Christopher B; Burdick, Jason A; Anseth, Kristi S

    2015-11-24

    Biomaterials that interface with biological systems are used to deliver drugs safely and efficiently; to prevent, detect, and treat disease; to assist the body as it heals; and to engineer functional tissues outside of the body for organ replacement. The field has evolved beyond selecting materials that were originally designed for other applications with a primary focus on properties that enabled restoration of function and mitigation of acute pathology. Biomaterials are now designed rationally with controlled structure and dynamic functionality to integrate with biological complexity and perform tailored, high-level functions in the body. The transition has been from permissive to promoting biomaterials that are no longer bioinert but bioactive. This perspective surveys recent developments in the field of polymeric and soft biomaterials with a specific emphasis on advances in nano- to macroscale control, static to dynamic functionality, and biocomplex materials.

  20. 3D Progressive Damage Modeling for Laminated Composite Based on Crack Band Theory and Continuum Damage Mechanics

    Science.gov (United States)

    Wang, John T.; Pineda, Evan J.; Ranatunga, Vipul; Smeltzer, Stanley S.

    2015-01-01

    A simple continuum damage mechanics (CDM) based 3D progressive damage analysis (PDA) tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code. This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al.'s formulation to incorporate the degrading material properties into the damaged stiffness matrix. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions. This CDM based PDA tool is implemented as a user defined material (VUMAT) to link with the Abaqus/Explicit code. Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads.

  1. Progress report, Chemistry and Materials Division

    International Nuclear Information System (INIS)

    Laser radiation has been used to anneal damage created by implantation of arsenic ions into silicon single-crystal wafers. The threshold for recovery of lattice order, as measured by ion channeling methods, appeared at an energy density of 1.2 J.cm-2. Deuterium-enriched water has been recovered for the first time in visible amounts from a process based on laser photolysis. High performance liquid chromatography has been applied to the determination of U(VI) in ground water and urine. Results with low ground water concentrations were judged to be successful, while only limited success was achieved with urine. The first analyses in support of the production of (Th,Pu)O2 fuel elements were completed successfully. Experiments performed during the quarter have shown that cracking of Zr-2.5 percent Nb alloy by gaseous hydrogen is inhibited by traces of oxygen. It was found that there was no inhibition by helium in the absence of trace oxygen. Excellent agreement has been obtained between the growth and creep constants derived from ion-irradiated cantilever beam specimens and those from reactor irradiation of the same materials. (O.T.)

  2. Multi-frequency resonator based on dual-band S-shaped left-handed material.

    Science.gov (United States)

    Wang, Dongxing; Ran, Lixin; Wu, Bae-Ian; Chen, Hongsheng; Huangfu, Jiangtao; Grzegorczyk, Tomasz M; Kong, J A

    2006-12-11

    In this paper, we experimentally realize a one-dimensional RHM (Right-handed Material)-LHM (Left-handed Material) multi-frequency resonator that consists of a dual-negative-band LHM and air arranged in an X-band waveguide. Multi-resonant frequencies are observed within two left-handed bands of the LHM. The effects of the loss and the hyperbolic dispersion relation of LHM layer are discussed. The incorporation of such a LHM into the resonator design allows more flexibility to realize multi-resonance. PMID:19529656

  3. Band inversion mechanism in topological insulators: A guideline for materials design

    KAUST Repository

    Zhu, Zhiyong

    2012-06-01

    Alteration of the topological order by band inversion is a key ingredient of a topologically nontrivial material. Using first-principles calculations for HgTe, PtScBi, and Bi2Se3, we argue that it is not accurate to ascribe the band inversion to the spin-orbit coupling. Instead, scalar relativistic effects and/or lattice distortions are found to be essential. Therefore, the search for topologically nontrivial materials should focus on band shifts due to these mechanisms rather than spin-orbit coupling. We propose an effective scheme to search for new topological insulators.

  4. Progress Toward Characterization of Juvenile Materials in Lunar Pyroclatic Deposits

    Science.gov (United States)

    Gaddis, L. R.

    1999-01-01

    In recent analyses, the 5-band Clementine UV-VIS data have been used to examine the compositions of lunar pyroclastic deposits. A primary goal of these analyses has been the characterization of the primary volcanic or juvenile components of these deposits. The compositions, physical and morphological characteristics, and spatial distributions of juvenile volcanic materials provide information on the distribution of primary mafic materials on the Moon, conditions required for their eruption at the surface, and the behavior of lunar volcanic processes over time. Using current analytical techniques with the new Clementine UV-VIS global mosaic, and data from the GLGM2 geophysical models, to supplement ongoing work with Earth-based spectral reflectance analyses and laboratory investigations, we have adopted a three-pronged approach to these issues involving: (1) compositional analyses of lunar pyroclastic deposits; (2) characterization of the relations between effusive and explosive lunar volcanism; and (3) examination of the global occurrence and distribution of lunar pyroclastic deposits. This report and related work describe progress toward remote characterization of the compositions of juvenile materials in the pyroclastic deposits located at Taurus-Littrow and J. Herschel. These studies have implications for characterization of the relations between the products of effusive and explosive volcanism on the Moon. Analyses of lunar pyroclastic materials, primarily the juvenile picritic glasses, provide unique information on the composition of the mantle and on the nature and origin of associated volatile elements in an otherwise volatile-depleted environment. Possible fundamental differences between picritic glasses and mare basalts, (e.g., lesser fractional crystallization and greater depth of origin for glasses) support their identification as the best examples of primitive materials on the Moon, and attest to their importance in characterizing the lunar interior and

  5. Recent Progress in Advanced Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jiajun Chen

    2013-01-01

    Full Text Available The development and commercialization of lithium ion batteries is rooted in material discovery. Promising new materials with high energy density are required for achieving the goal toward alternative forms of transportation. Over the past decade, significant progress and effort has been made in developing the new generation of Li-ion battery materials. In the review, I will focus on the recent advance of tin- and silicon-based anode materials. Additionally, new polyoxyanion cathodes, such as phosphates and silicates as cathode materials, will also be discussed.

  6. Identification of biologically recycled continental materials in banded iron formations

    Science.gov (United States)

    Li, W.; Beard, B. L.; Johnson, C.

    2015-12-01

    The controversy on the origin of banded iron formations (BIFs) has lasted for many decades. Studies prior to the 1970s suggested that Fe in BIFs was supplied from continental riverine inputs[1], but discovery of midocean ridge hydrothermal systems in the 1970s and identification of positive Eu anomaly in BIF samples led to an alternative model where hydrothermal vents provided Fe in BIFs[2]. Although the latter model has became widely accepted, it should be noted that interpretations of Fe sources for BIFs using the abundance and isotopic composition of rare earth elements (REEs) are based on an assumption that transport and deposition of REEs and Fe were coupled. We address the question of Fe sources and pathways for BIFs by combining stable Fe isotopes with radiogenic Nd isotopes as well as REE measurements to test proposals that Fe in BIFs was hydrothermally sourced. The samples investigated are from a type section of the Dales Gorge member of the 2.5 Ga Brockman Iron Formation, the world's most extensive Superior-type BIF that represents the climax of BIF deposition in the geologic record. Large variations were observed in both Fe and Nd isotope compositions of the BIF samples, and there is a positive correlation between the bulk rock ɛNd and δ56Fe values. In addition, there is a negative corelation between ɛNd and Sm/Nd ratios. In order to explain the observed correlations in those isotopic and elemental data, a two-component model, where mixing between a high ɛNd, low Sm/Nd hydrothermal endmember and a low ɛNd, low δ56Fe, but high Sm/Nd continental endmember occurred prior to deposition of the BIF, is required. The low-δ56Fe, high-Sm/Nd endmember is best explained by microbial dissimilatory iron reduction (DIR) in the coastal sediments, which fractionated Fe isotopes and REEs and released these components back to water column that were ultimately precipitated in BIFs. The range and distribution of ɛNdvalues in the BIF samples suggest that the amount

  7. Wide band-gap materials for high power electronics

    International Nuclear Information System (INIS)

    The wide gap semiconductors are the basis for the third generation of microelectronics and specially for the high end of the temperature range. In this presentation we will review the prospects and status of two members of this group: Diamond and Silicon Carbide (SiC). The two are at different stages of technological development and their respective modes of application at present are quite different. SiC devices can operate at up to 105 deg C. High power and high frequency devices have been demonstrated. Diamond is not yet ready for real electronic devices but its many extreme properties find their applications in several cases. The prospects of the future applications will be described in view of the semiconducting characteristics of these materials

  8. Recent progress of smart composite material in HIT

    Science.gov (United States)

    Leng, Jinsong; Yu, Kai; Liu, Yanju

    2010-03-01

    Recent progresses of smart composite material in our ongoing research are presented in this paper. In recent years, shape memory polymers (SMPs) and electroactive polymers (EAPs) attract more and more attention in the world. In our researching work, different kinds of reinforcement are embedded into SMPs and EAPs to form smart composite materials, aiming to improve the properties or strengthen the materials. Based on the unique properties of SMP based smart composite materials, primary application in the deployable morphing wing are also studied, which provide meaningful guidance for further researching works in this area.

  9. Recent progress of abrasion-resistant materials: learning from nature.

    Science.gov (United States)

    Meng, Jingxin; Zhang, Pengchao; Wang, Shutao

    2016-01-21

    Abrasion-resistant materials have attracted great attention for their broad applications in industry, biomedicine and military. However, the development of abrasion-resistant materials that have with unique features such as being lightweight and flexible remains a great challenge in order to satisfy unmet demands. The outstanding performance of natural abrasion-resistant materials motivates the development of new bio-inspired abrasion-resistant materials. This review summarizes the recent progress in the investigation of natural abrasion-resistant materials to explore their general design principles (i.e., the correlation between chemical components and structural features). Following natural design principles, several artificial abrasion-resistant materials have shown unique abrasion-resistant properties. The potential challenges in the future and possible solutions for designing bio-inspired abrasion-resistant materials are also briefly discussed. PMID:26335377

  10. Local resonance phononic band gaps in modified two-dimensional lattice materials

    Institute of Scientific and Technical Information of China (English)

    Wei Liu; Ji-Wei Chen; Xian-Yue Su

    2012-01-01

    In this paper,modified two-dimensional periodic lattice materials with local resonance phononic band gaps are designed and investigated.The design concept is to introduce some auxiliary structures into conventional periodic lattice materials.Elastic wave propagation in this kind of modified two-dimensional lattice materials is studied using a combination of Bloch's theorem with finite element method.The calculated frequency band structures of illustrative modified square lattice materials reveal the existence of frequency band gaps in the low frequency region due to the introduction of the auxiliary structures.The mechanism underlying the occurrence of these frequency band gaps is thoroughly discussed and natural resonances of the auxiliary structures are validated to be the origin.The effect of geometric parameters of the auxiliary structures on the width of the local resonance phononic band gaps is explored.Finally,a conceptual broadband vibration-insulating structure based on the modified lattice materials is designed and its capability is demonstrated.The present work is anticipated to be useful in designing structures which can insulate mechanical vibrations within desired frequency ranges.

  11. Intermediate band materials for more efficient solar energy use: quantum modelling and experimental realizations

    OpenAIRE

    Conesa, Jose Carlos; Wahnón Benarroch, Perla; Lucena, Raquel; Palacios Clemente, Pablo; Aguilera Bonet, Irene; Fresno, Fernando; Seminóvski Pérez, Yohanna

    2011-01-01

    The intermediate band (IB) solar cell (Fig. 1) has been proposed [1] to increase photovoltaic efficiency by a factor above 1.5, based on the absorption of two sub-bandgap photons to promote an electron across the bandgap. To realize this principle, that can be applied also to obtain efficient photocatalysis with sunlight, we proposed in recent years several materials where a metal or heavy element, substituting for an electropositive atom in a known semiconductor that has an appropriate band...

  12. Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain)]. E-mail: pablop@etsit.upm.es; Sanchez, K. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain); Conesa, J.C. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, Cantoblanco, 28049 Madrid (Spain); Fernandez, J.J. [Dpt. de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, 28080, Madrid (Spain); Wahnon, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2007-05-31

    Electronic structure calculations are carried out for CuGaS{sub 2} partially substituted with Ti, V, Cr or Mn to ascertain if some of these systems could provide an intermediate band material able to give a high efficiency photovoltaic cell. Trends in electronic level positions are analyzed and more accurate advanced theory levels (exact exchange or Hubbard-type methods) are used in some cases. The Ti-substituted system seems more likely to yield an intermediate band material with the desired properties, and furthermore seems realizable from the thermodynamic point of view, while those with Cr and Mn might give half-metal structures with applications in spintronics.

  13. Degradation of wide band-gap electrolumienscent materials by exciton-polaron interactions (Presentation Recording)

    Science.gov (United States)

    Aziz, Hany; Wang, Qi

    2015-10-01

    The limited performance stability and gradual loss in the electroluminescence efficiency of OLEDs utilizing wide band-gap materials, such as blue-emitting phosphorescent and fluorescent devices, continues to be a challenge for wider technology adoption. We recently found that interactions between excitons and polarons play an important role in the aging behavior of electroluminescent materials, and that a correlation exists between the susceptibility of these materials to this aging mode and their band-gap. This degradation mode is also found to be often associated with the emergence of new bands - at longer wavelength - in the electroluminescence spectra of the materials, that can often be detected after prolonged electrical driving. Such bands contribute to the increased spectral broadening and color purity loss often observed in these devices over time. Exciton-polaron interactions, and the associated degradation, are also found to occur most significantly in the vicinity of device inter-layer interfaces such as at the interface between the emitter layer and the electron or hole transport layers. New results obtained from investigations of these phenomena in a wide range of commonly used host and guest OLED materials will be presented.

  14. Materials identification synthetic aperture radar: progress toward a realized capability

    International Nuclear Information System (INIS)

    Most non-metallic materials have frequency-dependent reflectivity functions, that is, they reflect electromagnetic energy in a manner that depends on frequency. Pulsed-chirped synthetic aperture radar and other multispectral radar systems do not generally take into account the frequency dependence of material reflections in forming scenes or making other inferences. In this report, we introduce a simple mathematical approach to using existing pulsed chirp synthetic aperture systems in a manner which results in a determination of a frequency-dependent reflectivity function for each pixel in a computed scene. Our analysis of collected data suggests that the method may be useful to distinguish disturbed from non-disturbed earth, and to detect chemicals on the surface of the earth. The method we have developed provides the analyst with a vector above each pixel with each vector component referencing a frequency band. This additional information may be useful for considering surface texture, subsurface layering and materials identification. (paper)

  15. Rapid progression of band-shaped keratopathy with early central localisation in a patient on chronic dialytic treatment.

    Science.gov (United States)

    Klaassen-Broekema, N; Van Bijsterveld, O P

    1994-01-01

    This clinical study reports on an unusual start of a band-shaped keratopathy in a patient with diabetic nephropathy on dialytic treatment. The earliest corneal manifestations were centrally located small greyish-white disc-shaped lesions evenly distributed in the interpalpebral area in the left eye. Later a typical peripheral band-shaped keratopathy developed. In the course of the observation period the peripheral keratopathy rapidly spread towards the centre, finally resulting in a complete band-shaped keratopathy in which only the most central original disc-shaped lesions could be identified. Serum calcium and phosphorus concentrations were markedly elevated at the time of the progression of the band-shaped keratopathy but no tertiary hyperparathyroidism was present.

  16. Mechanisms for axial band formation in a rotating drum of granular material

    Science.gov (United States)

    Newey, Michael K.

    We study granular particles, like sand or glass beads, that are mixed in a partially filled, horizontal, cylindrical drum. When the drum is rotated, it is observed that there is a flowing layer of grains on the free surface of the granular medium. In addition, if the particles have different sizes, spatial segregation of the particles by size is observed. This segregation occurs in two phases. During the first phase, called radial segregation, the smaller particles form a radial core. In the second, called axial segregation, particles segregate into alternating bands along the axis of the drum. We perform a detailed study of the characteristics of the flow to determine the physical mechanisms driving axial segregation. We characterize the top surface of the flowing layer by tracking particles using a high speed camera. We then extract average quantities such as velocity and diffusion. The average velocities show surprising behavior: Particles in small particle bands have a higher downhill flow velocity than particles in large particle bands. We also observe that there is a pattern of sideways velocity as a function of position down the flow. Particles flow into small particle bands in the middle of the flow but flow out of small particle bands at the bottom. We present the framework for a new model based on our experimentally observed results. We explain the axial band formation in terms of the observed surface flow patterns. We show how two physical processes could contribute to the band formation: (A) Accelerating granular material does not necessarily collide while decelerating granular material requires collisions. (B) Different size particles flow at different velocities. Our framework connects differences in flow velocities on the surface of the drum with the radial segregation in the bulk of the drum. We compare these results to current models, including models by Savage, Zik, Aranson, and Elperin. We test the general model assumption that the particles

  17. Experimental method for the evaluation of the susceptibility of materials to shear band formation

    Directory of Open Access Journals (Sweden)

    Tham R.

    2012-08-01

    Full Text Available In order to characterize materials with respect to their susceptibility to shear band formation at high strain rates, a modified Hopkinson pressure bar apparatus and hat-shaped steel specimens with a shear zone having a width significantly larger than the typical width of adiabatic bands are used. The sample is directly impacted by the striker. The force acting on the sample is measured with a PVDF-gauge between the sample and the output bar. The displacement is recorded with an electro-optical extensometer. The energy absorbed by the shearing process up to failure can be used as a reference for the susceptibility of materials to shear band formation. The method is demonstrated comparing the shear behavior of two high-strength steels with similar metallic structure and strength. Differences were found in the transition region between quasi-static and fully adiabatic shearing conditions where the energy up to rupture differs by 40 %. For fully adiabatic shear band formation, the deformation process of both materials equals. At extreme rates, shear processes are mainly governed by the thermodynamic properties of the materials. On the other hand, strength and structural properties play a role for low and intermediate rates where global and localized shear mechanisms occur in parallel.

  18. Electronic and thermoelectric properties of van der Waals materials with ring-shaped valence bands

    International Nuclear Information System (INIS)

    The valence band of a variety of few-layer, two-dimensional materials consist of a ring of states in the Brillouin zone. The energy-momentum relation has the form of a “Mexican hat” or a Rashba dispersion. The two-dimensional density of states is singular at or near the band edge, and the band-edge density of modes turns on nearly abruptly as a step function. The large band-edge density of modes enhances the Seebeck coefficient, the power factor, and the thermoelectric figure of merit ZT. Electronic and thermoelectric properties are determined from ab initio calculations for few-layer III–VI materials GaS, GaSe, InS, InSe, for Bi2Se3, for monolayer Bi, and for bilayer graphene as a function of vertical field. The effect of interlayer coupling on these properties in few-layer III–VI materials and Bi2Se3 is described. Analytical models provide insight into the layer dependent trends that are relatively consistent for all of these few-layer materials. Vertically biased bilayer graphene could serve as an experimental test-bed for measuring these effects

  19. Recent progress of plasma facing material research at SWIP

    International Nuclear Information System (INIS)

    Vacuum sprayed tungsten coating and vacuum hot press beryllium as plasma facing materials were being studied at Southwestern Institute of Physics (SWIP) recently several years according to the domestic fusion research and development program and ITER-China fabrication tasks. The former will be tested as the armor materials of limiters in the HL-2A tokamak, and might be also tested in the modified tokamak machine HL-2M. The latter will be used for ITER-FW mock-ups if it satisfied the requirements of ITER qualification tests. In this paper the progress of VPS-W coating and VHP-Be will be reviewed. (author)

  20. Efficient thermoelectric materials using nonmagnetic double perovskites with d0/d6 band filling

    Science.gov (United States)

    Villar Arribi, Pablo; García-Fernández, Pablo; Junquera, Javier; Pardo, Victor

    2016-07-01

    Efficient thermoelectric materials should present large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. An enhanced Seebeck coefficient can be obtained from materials where the Fermi level can be aligned with a large and narrow peak of the density of states, particularly when a substantial band valley degeneracy occurs. A high electrical conductivity comes as a consequence of large conductive hopping paths between the atoms of the material. Both physical quantities can be decoupled and optimized independently if their origins can be ascribed to different sets of bands. Based on these assumptions, double perovskites A2BB 'O6 with d0/d6 filling for the B and B' metal cations, respectively, have been considered. They provide a desirable band structure with degenerate B -t2 g / B'-eg bands above the Fermi level together with a low thermal conductivity. We have carried out first-principles simulations for various of these nonmagnetic double perovskites and showed that all of them present a large Seebeck coefficient (consequence of the localized and empty t2 g states of the B cation), and large electrical conductivity due to the more spread unoccupied eg band of the B' cation. We have seen that if they can be optimally doped, they could show a figure of merit comparable or even higher than the best n -type thermoelectric oxides, such as SrTiO3. Different mechanisms to tune the band structure and enhance the thermoelectric figure of merit are explored, including epitaxial strain, hydrostatic pressure, chemical pressure, and external doping. A fully relaxed structure has also been studied, showing that a realistic calculation is necessary to make accurate predictions but also proving that the main trends shown throughout the paper remain unchanged.

  1. Two-dimensional microwave band-gap structures of different dielectric materials

    Indian Academy of Sciences (India)

    E D V Nagesh; G Santosh Babu; V Subramanian; V Sivasubramanian; V R K Murthy

    2005-12-01

    We report the use of low dielectric constant materials to form two-dimensional microwave band-gap structures for achieving high gap-to-midgap ratio. The variable parameters chosen are the lattice spacing and the geometric structure. The selected geometries are square and triangular and the materials chosen are PTFE ( = 2.1), PVC ( = 2.38) and glass ( = 5.5). Using the plane-wave expansion method, proper lattice spacing is selected for each structure and material. The observed experimental results are analyzed with the help of the theoretical prediction.

  2. Experimental characterization of negative refractive index material NRM at Ka band

    CERN Document Server

    Chatterjee, Sougata

    2016-01-01

    In this paper, we discuss the experimental characterization of a negative refractive material NRM at Ka band using LR labyrinth Ring and wire array WA. We describe in detail the the LR and wire array characterization separately, and after that the combined experimental results, for NRM are reported. The LRs analytical and simulation study is not new but design in Ka band and different experimental procedure for the characterization of the negative refractive index is the novelty of this paper. For performing a negative refractive index experiment we made prism of 150 Prism angle . We get enhanced transmittance of more than 20 dB from background, at a negative angle of refraction. The values of the negative refractive index in a band of about 1 G Hz around 31 GHz are retrieved from the experimental data.

  3. Validity of rigid band approximation of PbTe thermoelectric materials

    Directory of Open Access Journals (Sweden)

    Yoshiki Takagiwa

    2013-07-01

    Full Text Available The tuning of carrier concentration through chemical doping is very important for the optimization of thermoelectric materials. Traditionally, a rigid band model is used to understand and guide doping in such semiconductors, but it is not clear whether such an approximation is valid. This letter focuses on the changes in the electronic density of states (DOS near the valence band maximum for different p-type dopants (Na, K, Tl, or vacancy on Pb site maintaining the high symmetry of the NaCl structure. Na- and K-doped, and vacancy-introduced PbTe show a clear rigid-band like change in DOS unlike that concluded from supercell based calculations.

  4. A theoretical approach of strain localization within thin planar bands in porous ductile materials

    Science.gov (United States)

    Leblond, Jean-Baptiste; Mottet, Gérard

    2008-01-01

    Propagation of cracks in ductile materials is well known to occur through two possible mechanisms: coalescence of cavities and formation of shear bands ('void sheet mechanism'). The classical Gurson-Tvergaard-Needleman (GTN) homogenized model for such materials incorporates some phenomenological modelling of coalescence, but not of formation of shear bands assisted by the presence of microvoids, and this generates a number of shortcomings. In order to solve these difficulties, this paper presents a unified model of both coalescence and formation of shear bands in porous plastic solids, including the possible couplings between the two. Both phenomena are viewed as expressions of the same basic effect, namely strain localization within thin planar bands, the only difference being the mode of deformation. The model is first developed assuming a periodic distribution of cavities, then critically assessed through comparison with some micromechanical numerical simulations based on the same assumption, and finally extended to the case of a random distribution of voids. To cite this article: J.-B. Leblond, G. Mottet, C. R. Mecanique 336 (2008).

  5. Recent progress in injectable bone repair materials research

    Science.gov (United States)

    Chen, Zonggang; Zhang, Xiuli; Kang, Lingzhi; Xu, Fei; Wang, Zhaoling; Cui, Fu-Zhai; Guo, Zhongwu

    2015-12-01

    Minimally invasive injectable self-setting materials are useful for bone repairs and for bone tissue regeneration in situ. Due to the potential advantages of these materials, such as causing minimal tissue injury, nearly no influence on blood supply, easy operation and negligible postoperative pain, they have shown great promises and successes in clinical applications. It has been proposed that an ideal injectable bone repair material should have features similar to that of natural bones, in terms of both the microstructure and the composition, so that it not only provides adequate stimulus to facilitate cell adhesion, proliferation and differentiation but also offers a satisfactory biological environment for new bone to grow at the implantation site. This article reviews the properties and applications of injectable bone repair materials, including those that are based on natural and synthetic polymers, calcium phosphate, calcium phosphate/polymer composites and calcium sulfate, to orthopedics and bone tissue repairs, as well as the progress made in biomimetic fabrication of injectable bone repair materials.

  6. Band structures tunability of bulk 2D phononic crystals made of magneto-elastic materials

    Directory of Open Access Journals (Sweden)

    J. O. Vasseur

    2011-12-01

    Full Text Available The feasibility of contactless tunability of the band structure of two-dimensional phononic crystals is demonstrated by employing magnetostrictive materials and applying an external magnetic field. The influence of the amplitude and of the orientation with respect to the inclusion axis of the applied magnetic field are studied in details. Applications to tunable selective frequency filters with switching functionnality and to reconfigurable wave-guides and demultiplexing devices are then discussed.

  7. Synergistic Use of Genetic Algorithm and Spectral Angle Mapper for Hyperspectral Band Selection of Roof Materials

    OpenAIRE

    Bahareh KALANTAR; Helmi Zulhaidi Mohd SHAFRI

    2016-01-01

    Hyperspectral data are valuable for urban studies because of the continuous narrow bands and high spectral resolution of such data. However, using hyperspectral data presents certain difficulties because of the high dimensionality. Hyperspectral data dimensionality should be reduced without losing the spectral detail of the data. In this study, we aim to assess the capability of hyperspectral data to discriminate roof materials and evaluate the feasibility of the genetic algorithm (GA) combin...

  8. Final Report: Laser-Material Interactions Relevant to Analytic Spectroscopy of Wide Band Gap Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dickinson, J. T. [Washington State University

    2014-04-05

    We summarize our studies aimed at developing an understanding of the underlying physics and chemistry in terms of laser materials interactions relevant to laser-based sampling and chemical analysis of wide bandgap materials. This work focused on the determination of mechanisms for the emission of electrons, ions, atoms, and molecules from laser irradiation of surfaces. We determined the important role of defects on these emissions, the thermal, chemical, and physical interactions responsible for matrix effects and mass-dependent transport/detection. This work supported development of new techniques and technology for the determination of trace elements contained such as nuclear waste materials.

  9. Wave propagation in ordered, disordered, and nonlinear photonic band gap materials

    Energy Technology Data Exchange (ETDEWEB)

    Lidorikis, Elefterios

    1999-12-10

    Photonic band gap materials are artificial dielectric structures that give the promise of molding and controlling the flow of optical light the same way semiconductors mold and control the electric current flow. In this dissertation the author studied two areas of photonic band gap materials. The first area is focused on the properties of one-dimensional PBG materials doped with Kerr-type nonlinear material, while, the second area is focused on the mechanisms responsible for the gap formation as well as other properties of two-dimensional PBG materials. He first studied, in Chapter 2, the general adequacy of an approximate structure model in which the nonlinearity is assumed to be concentrated in equally-spaced very thin layers, or 6-functions, while the rest of the space is linear. This model had been used before, but its range of validity and the physical reasons for its limitations were not quite clear yet. He performed an extensive examination of many aspects of the model's nonlinear response and comparison against more realistic models with finite-width nonlinear layers, and found that the d-function model is quite adequate, capturing the essential features in the transmission characteristics. The author found one exception, coming from the deficiency of processing a rigid bottom band edge, i.e. the upper edge of the gaps is always independent of the refraction index contrast. This causes the model to miss-predict that there are no soliton solutions for a positive Kerr-coefficient, something known to be untrue.

  10. Progress, challenges, and opportunities for HgCdTe infrared materials and detectors

    Science.gov (United States)

    Lei, Wen; Antoszewski, Jarek; Faraone, Lorenzo

    2015-12-01

    This article presents a review on the current status, challenges, and potential future development opportunities for HgCdTe infrared materials and detector technology. A brief history of HgCdTe infrared technology is firstly summarized and discussed, leading to the conclusion that HgCdTe-based infrared detectors will continue to be a core infrared technology with expanded capabilities in the future due to a unique combination of its favourable properties. Recent progress and the current status of HgCdTe infrared technology are reviewed, including material growth, device architecture, device processing, surface passivation, and focal plane array applications. The further development of infrared applications requires that future infrared detectors have the features of lower cost, smaller pixel size, larger array format size, higher operating temperature, and multi-band detection, which presents a number of serious challenges to current HgCdTe-based infrared technology. The primary challenges include well controlled p-type doping, lower cost, larger array format size, higher operating temperature, multi-band detection, and advanced plasma dry etching. Various new concepts and technologies are proposed and discussed that have the potential to overcome the existing primary challenges that are inhibiting the development of next generation HgCdTe infrared detector technology.

  11. Omnidirectional Photonic Band Gap Using Low Refractive Index Contrast Materials and its Application in Optical Waveguides

    KAUST Repository

    Vidal Faez, Angelo

    2012-07-01

    Researchers have argued for many years that one of the conditions for omnidirectional reflection in a one-dimensional photonic crystal is a strong refractive index contrast between the two constituent dielectric materials. Using numerical simulations and the theory of Anderson localization of light, in this work we demonstrate that an omnidirectional band gap can indeed be created utilizing low refractive index contrast materials when they are arranged in a disordered manner. Moreover, the size of the omnidirectional band gap becomes a controllable parameter, which now depends on the number of layers and not only on the refractive index contrast of the system, as it is widely accepted. This achievement constitutes a major breakthrough in the field since it allows for the development of cheaper and more efficient technologies. Of particular interest is the case of high index contrast one-dimensional photonic crystal fibers, where the propagation losses are mainly due to increased optical scattering from sidewall roughness at the interfaces of high index contrast materials. By using low index contrast materials these losses can be reduced dramatically, while maintaining the confinement capability of the waveguide. This is just one of many applications that could be proven useful for this discovery.

  12. Amorphous silicon materials and solar cells - Progress and directions

    Science.gov (United States)

    Sabisky, E.; Mahan, H.; McMahon, T.

    In 1978, the U.S. Department of Energy initiated government sponsored research in amorphous materials and thin film solar cells. The program was subsequently transferred to the Solar Energy Research Institute for program management. The program grew into a major program for the development of high efficiency (greater than 10 percent), cost effective (15-40 cents per peak watt) thin film amorphous solar cells. The present international interest, the substantial progress made in the device area (2 percent PIN cell in 1976 to 10 percent PIN cell in 1982), and the marketing of the first consumer products using thin film solar cells are to a large ducts using thin film solar cells are to a large extent a consequence of this goal-oriented program.

  13. Progress on polarized target materials with pure carbon background

    International Nuclear Information System (INIS)

    A previous note reviewed methods for the paramagnetic doping of materials for spin-polarized solid targets and some of the history of attempts to apply those methods to hydrocarbons. Since the earlier work on hydrocarbons had yielded, at best, rather mediocre results, that note also speculated on some ways to extend and, possibly, to improve upon the earlier work. The sharpest focus was on the light (number of carbons less than six) alkanes, since these are the hydrocarbons that have the highest hydrogen contents (approx-gt 17wt %) and therefore require the least degree of polarization to be interesting. This present note summarizes the subsequent work done, to date, exploring some of the issues related to the chemical doping method. The main areas of progress have been in the literature search, experimental results on glass formation by alkanes, and a polarizing test of a ''prototype'' hydrocarbon

  14. MATRIX research group for materials research utilizing NSLS. Progress report

    International Nuclear Information System (INIS)

    MATRIX is a group of scientists from nine institutions who have common interests in utilizing x-ray synchrotron radiation for unique materials research. This group has available to it a specialized beam line for a wide range of x-ray scattering studies at the National Light Synchrotron Source (NSLS). In the development of this beam line the MATRIX group has been a leader in all phases of beam line development. During the past year, MATRIX completed the first operational x-ray scattering beam line at NSLS. In addition, the first x-ray scattering experiment at NSLS was conducted on this beam line. In the past year, eight publications have resulted from the MATRIX supported efforts. Among these publications are four studies related to the beam line development and characteristics. The other publications are research projects of preliminary studies for work at NSLS and include projects on catalysts and phase transformations. Full operational schedules covering the remainder of the calendar year for the beam line were initiated in June 1985. In addition to the first completed project on Diffraction Studies of Langmuir-Blodgett Films, a number of projects on phase transformations, surface studies, catalysts, and electronic materials are in progress. Associated with the research projects in progress, part of the efforts of the MATRIX group has involved final testing of two unique systems for the beam line. An X-ray Diffraction Surface Chamber that will allow diffraction studies as well as surface characterization (LEED, Auger spectroscopy, and sputtering) is undergoing final completion and testing. Also, a Time Resolved Detection System which allows 30 nsec resolution is in final operational testing on a rotating anode. Both systems are scheduled for installation on the beam line in late 1985. 3 figs., 1 tab

  15. Cerebrospinal fluid oligoclonal bands and progression of disability in multiple sclerosis

    NARCIS (Netherlands)

    Koch, M.; Heersema, D.; Mostert, J.; Teelken, A.; De Keyser, J.

    2007-01-01

    Antibody-mediated inflammation is believed to contribute to tissue injury in multiple sclerosis (MS). The majority of patients with MS have oligoclonal bands (OCB), corresponding to antibodies against a variety of antigens, in their cerebrospinal fluid (CSF). The relation of CSF OCB and disease prog

  16. MxF6bius bands, unstretchable material sheets and developable surfaces

    Science.gov (United States)

    Chen, Yi-chao; Fried, Eliot

    2016-08-01

    A Möbius band can be formed by bending a sufficiently long rectangular unstretchable material sheet and joining the two short ends after twisting by 180°. This process can be modelled by an isometric mapping from a rectangular region to a developable surface in three-dimensional Euclidean space. Attempts have been made to determine the equilibrium shape of a Möbius band by minimizing the bending energy in the class of mappings from the rectangular region to the collection of developable surfaces. In this work, we show that, although a surface obtained from an isometric mapping of a prescribed planar region must be developable, a mapping from a prescribed planar region to a developable surface is not necessarily isometric. Based on this, we demonstrate that the notion of a rectifying developable cannot be used to describe a pure bending of a rectangular region into a Möbius band or a generic ribbon, as has been erroneously done in many publications. Specifically, our analysis shows that the mapping from a prescribed planar region to a rectifying developable surface is isometric only if that surface is cylindrical with the midline being the generator. Towards providing solutions to this issue, we discuss several alternative modelling strategies that respect the distinction between the physical constraint of unstretchability and the geometrical notion of developability.

  17. Measurement of losses of mesh membrane material for reflector applications with an S-band radiometer

    Science.gov (United States)

    Blume, H. J. C.

    1982-03-01

    The spatial resolution, the frequency of revisits, and the accuracy requirements for the detection of Earth surface parameters from space force the satellite designers to consider large space structures for microwaves. Some Earth surface parameters are only detectable with radiometers. Because the large reflectors should be much lighter than solid and deployable reflectors, mesh membrane material is considered to be used as the reflector. It is essential to determine the emissivity of the reflecting material even when close to zero to estimate the accuracy of the radiometer measurement. An existing S-band radiometer was used to determine the loss of a 1 sq m pretensioned mesh first in a field experiment and later in a well shielded laboratory set-up. The models for retrieving the emissivity of the mesh are described in detail and the equivalent losses for different mesh positions were calculated.

  18. 8-band and 14-band kp modeling of electronic band structure and material gain in Ga(In)AsBi quantum wells grown on GaAs and InP substrates

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, M.; Wartak, M. S. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Kudrawiec, R. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2015-08-07

    The electronic band structure and material gain have been calculated for GaAsBi/GaAs quantum wells (QWs) with various bismuth concentrations (Bi ≤ 15%) within the 8-band and 14-band kp models. The 14-band kp model was obtained by extending the standard 8-band kp Hamiltonian by the valence band anticrossing (VBAC) Hamiltonian, which is widely used to describe Bi-related changes in the electronic band structure of dilute bismides. It has been shown that in the range of low carrier concentrations n < 5 × 10{sup 18 }cm{sup −3}, material gain spectra calculated within 8- and 14-band kp Hamiltonians are similar. It means that the 8-band kp model can be used to calculate material gain in dilute bismides QWs. Therefore, it can be applied to analyze QWs containing new dilute bismides for which the VBAC parameters are unknown. Thus, the energy gap and electron effective mass for Bi-containing materials are used instead of VBAC parameters. The electronic band structure and material gain have been calculated for 8 nm wide GaInAsBi QWs on GaAs and InP substrates with various compositions. In these QWs, Bi concentration was varied from 0% to 5% and indium concentration was tuned in order to keep the same compressive strain (ε = 2%) in QW region. For GaInAsBi/GaAs QW with 5% Bi, gain peak was determined to be at about 1.5 μm. It means that it can be possible to achieve emission at telecommunication windows (i.e., 1.3 μm and 1.55 μm) for GaAs-based lasers containing GaInAsBi/GaAs QWs. For GaInAsBi/Ga{sub 0.47}In{sub 0.53}As/InP QWs with 5% Bi, gain peak is predicted to be at about 4.0 μm, i.e., at the wavelengths that are not available in current InP-based lasers.

  19. Strain Gage Test Results of Band-Type Locking Rings for a Typical Drum Type Radioactive Material Package

    International Nuclear Information System (INIS)

    Band type closure rings are commonly used for securing the drum lid on radioactive material packages of lower weight classifications. Lid installation is achieved by placing the band around the perimeter of the lidded drum and tightening the single bolt in stages until a designated torque value is obtained. The band is subjected to heavy rapping with a soft hammer during installation to equilibrate the band strains around the drum perimeter. The study described here investigated the strain distributions in the band throughout the installation process. The results show that a uniform strain distribution is achieved during installation and that the hammering of the band aids in achieving the uniform distribution. The results of the strain levels after the drop test indicate that the locking rings maintain some pre-tension, even after severe targeted drops that crush a portion of the drum top

  20. Kaolinite: Defect defined material properties – A soft X-ray and first principles study of the band gap

    Energy Technology Data Exchange (ETDEWEB)

    Pietzsch, A., E-mail: annette.pietzsch@helmholtz-berlin.de [Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Nisar, J. [Pakistan Atomic Energy Commission (PAEC), P.O. Box 2151, Islamabad (Pakistan); Jämstorp, E. [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Gråsjö, J. [Department of Pharmacy, Uppsala University, Box 580, 75123 Uppsala (Sweden); Århammar, C. [Coromant R& D, S-126 80 Stockholm (Sweden); Ahuja, R.; Rubensson, J.-E. [Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala (Sweden)

    2015-07-15

    Highlights: • The respective electronic structure of synthetic and natural kaolinite is compared. • The size of the band gap and thus many important material properties are defined by defect states in the band gap. • The oxygen-based defect states are identified and analyzed. • The band gap of kaolinite decreases significantly due to the forming of defects. - Abstract: By combining X-ray absorption spectroscopy and first principles calculations we have determined the electronic structure of synthetic and natural kaolinite as a model system for engineered and natural clay materials. We have analyzed defect states in the band gap and find that both natural and synthetic kaolinite contain defects where oxygen replaces hydrogen in one of the Al (0 0 1)-hydroxyl groups of the kaolinite clay sheets. The band gap of both synthetic and natural kaolinite is found to decrease by about 3.2 eV as this defect is formed.

  1. VIIRS Reflective Solar Bands Calibration Progress and Its Impact on Ocean Color Products

    Directory of Open Access Journals (Sweden)

    Junqiang Sun

    2016-02-01

    Full Text Available The radiometric calibration for the reflective solar bands (RSB of the Visible Infrared Imaging Radiometer Suite (VIIRS on board the Suomi National Polar-orbiting Partnership (SNPP platform has reached a mature stage after four years since its launch. The characterization of the vignetting effect of the attenuation screens, the bidirectional reflectance factor of the solar diffuser, the degradation performance of the solar diffuser, and the calibration coefficient of the RSB have all been made robust. Additional investigations into the time-dependent out-of-band relative spectral response and the solar diffuser degradation non-uniformity effect have led to newer insights. In particular, it has been demonstrated that the solar diffuser (SD degradation non-uniformity effect induces long-term bias in the SD-calibration result. A mitigation approach, the so-called Hybrid Method, incorporating lunar-based calibration results, successfully restores the calibration to achieve ~0.2% level accuracy. The successfully calibrated RSB data record significantly impacts the ocean color products, whose stringent requirements are especially sensitive to calibration accuracy, and helps the ocean color products to reach maturity.

  2. Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band

    Directory of Open Access Journals (Sweden)

    Avanish Pratap Singh

    2011-06-01

    Full Text Available β–Naphthalene sulphonic acid (β–NSA doped polyaniline (PANI–flyash (FA composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37–21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D–VRH model. SEM images demonstrate that β–NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ′- iɛ″ and permeability (μ*=μ′- iμ″ of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21 using theoretical calculations given in Nicholson–Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 – 12.4 GHz & Ku–Band (12.4 – 18 GHz frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.

  3. New intermediate band materials for better use of solar spectrum in photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, P.; Aguilera, I.; Sanchez, K.; Wahnon, P. [Universidad Politecnica de Madrid (Spain). Inst. de Energia Solar; Lucena, R.; Conesa, J.C. [Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Inst. de Catalisis y Petroleoquimica

    2010-07-01

    More efficient photovoltaic conversion of solar energy has been proposed to be possible by using intermediate band (IB) materials. In these an isolated, partially filled IB within the gap of a semiconductor allows electrons to be excited in the latter from its valence band to its conduction band in two steps, using photons of energy lower than that of the main gap E{sub g}. The ideal efficiency limit can then be pushed from 42% (the Queisser value) to over 63% (for an optimum E{sub g} value of {approx}e eV). In the last years we have indicated, on the basis of DFT simulations, those IB characteristics can be obtained with typical semiconductors in which an electropositive element is substituted by a judiciously chosen transition metal, which can provide partially filled d electronic states at the appropriate energy position. Besides GaP(As) or CuGaS{sub 2} with Ga substituted by Ti or Cr at the 2-10% level, we propose more recently octahedral semiconductors that contain the electropositive element to be substituted (e.g. In, Sn, Sc) in octahedral coordination. Also some Si-based structures including transition metal atoms have been shown to have the desired IB properties. For some of these compounds we have carried out thea in-lab experimental proparation and the verification that sub-bandgap photon absorption takes place, in agreement with the quantum modelling predictions of electronic structure and absorption coefficient. The current status of these different proposals and the last results obtained on these systems will be presented. (orig.)

  4. Graphene nanoribbon-PVA composite as EMI shielding material in the X band

    Science.gov (United States)

    Joshi, Anupama; Bajaj, Anil; Singh, Rajvinder; Alegaonkar, P. S.; Balasubramanian, K.; Datar, Suwarna

    2013-11-01

    A very thin graphene nanoribbon/polyvinyl alcohol (GNR/PVA) composite film has been developed which is light weight and requires a very low concentration of filler to achieve electromagnetic interference (EMI) shielding as high as 60 dB in the X band. Atomic force microscope studies show very well conjugated filler concentration in the PVA matrix for varying concentrations of GNR supported by Raman spectroscopy data. The films show 14 orders of increase in conductivity with a GNR concentration of 0.0075 wt% in PVA. This is possible because of the interconnected GNR network providing a very low percolation threshold as observed from the electrical measurements. Local density of states study of GNR using scanning tunnelling spectroscopy shows the presence of localized states near the Fermi energy. There are multiple advantages of GNR as an EMI shielding material in a polymer matrix. It has good dispersion in water, the conductive network in the composite shows very high electrical conductivity for a very low concentration of GNR and the presence of localized density of states near Fermi energy provides the spin states required for the absorbance of radiation energy in the X band.

  5. The Propagation, Excitation and Coupling of Acoustic Waves in Phonon Band-gap Materials

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Propagation, Excitation and Coupling of Acoustic Waves in Phonon Band-gap Materials[1]Lu Yan-qing,Zhu Yong-yuan,Chen Yan-feng,et al.Science,1999,284:1822-1824. [2]Zhu Yong-yuan,Zhang Xue-jin,Lu Yan-qing,et al.Phys.Rev.Lett,2003,90:053903. [3]Zhang Xue-jing,Zhu Ran-qi,Zhao Jun,et al.Phys.Rev.B,2004,69:085118. [4]Zhang Xue-jing,Lu Yan-qing,Zhu Yong-yuan,et al.Appl.Phys.Lett,2004,85:3531-3533. [5]Feng Liang,Liu Xiao-ping,Tang Yue-feng Tang,et al.Phys.Rev.B,2005,71:195106. [6]Feng Liang,Liu X...

  6. Band Gap Engineering in a 2D Material for Solar-to-Chemical Energy Conversion.

    Science.gov (United States)

    Hu, Jun; Guo, Zhenkun; Mcwilliams, Peter E; Darges, John E; Druffel, Daniel L; Moran, Andrew M; Warren, Scott C

    2016-01-13

    The electronic structure of 2D semiconductors depends on their thickness, providing new opportunities to engineer semiconductors for energy conversion, electronics, and catalysis. Here we show how a 3D semiconductor, black phosphorus, becomes active for solar-to-chemical energy conversion when it is thinned to a 2D material. The increase in its band gap, from 0.3 eV (3D) to 2.1 eV (2D monolayer), is accompanied by a 40-fold enhancement in the formation of chemical products. Despite this enhancement, smaller flakes also have shorter excited state lifetimes. We deduce a mechanism in which recombination occurs at flake edges, while the "van der Waals" surface of black phosphorus bonds to chemical intermediates and facilitates electron transfer. The unique properties of black phosphorus highlight its potential as a customizable material for solar energy conversion and catalysis, while also allowing us to identify design rules for 2D photocatalysts that will enable further improvements in these materials.

  7. The Shifts of Band Gap and Binding Energies of Titania/Hydroxyapatite Material

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Truc Linh

    2014-01-01

    Full Text Available The titania/hydroxyapatite (TiO2/HAp product was prepared by precipitating hydroxyapatite in the presence of TiO(OH2 gel in the hydrothermal system. The characteristics of the material were determined by using the measurements such as X-ray photoemission spectroscopy (XPS, X-ray diffraction (XRD, diffuse reflectance spectra (DRS, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and energy dispersive X-ray (EDX. The XPS analysis showed that the binding energy values of Ca (2p1/2, 2p3/2, P (2p1/2, 2p3/2, and O 1s levels related to hydroxyapatite phase whereas those of Ti (2p3/2, 2p1/2 levels corresponded with the characterization of titanium (IV in TiO2. The XRD result revealed that TiO2/HAp sample had hydroxyapatite phase, but anatase or rutile phases were not found out. TEM image of TiO2/HAp product showed that the surface of the plate-shaped HAp particles had a lot of smaller particles which were considered as the compound of Ti. The experimental band gap of TiO2/HAp material calculated by the DRS measurement was 3.6 eV, while that of HAp pure was 5.3 eV and that of TiO2 pure was around 3.2 eV. The shift of the band gap energy of TiO2 in the range of 3.2–3.6 eV may be related to the shifts of Ti signals of XPS spectrum.

  8. Progress on research of materials science and biotechnology by ion beam application

    Energy Technology Data Exchange (ETDEWEB)

    Ishigaki, Isao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Research of materials science and biotechnology by ion beam application in Takasaki Establishment was reviewed. Especially, the recent progresses of research on semiconductors in space, creation of new functional materials and topics in biotechnology were reported. (author)

  9. The Role of Short-Range Order and Hyperuniformity in the Formation of Band Gaps in Disordered Photonic Materials

    CERN Document Server

    Froufe-Pérez, Luis S; Damasceno, Pablo F; Muller, Nicolas; Haberko, Jakub; Glotzer, Sharon C; Scheffold, Frank

    2016-01-01

    We study photonic band gap formation in two-dimensional high refractive index disordered ma- terials where the dielectric structure is derived from packing disks in real and reciprocal space. Numerical calculations of the photonic density of states demonstrate the presence of a band gap for all polarizations in both cases. We find that the band gap width is controlled by the increase in positional correlation inducing short-range order and hyperuniformity concurrently. Our findings suggest that the optimization of short-range order, in particular the tailoring of Bragg scattering at the isotropic Brillouin zone, are of key importance for designing disordered PBG materials.

  10. FY2009 Annual Progress Report for Propulsion Materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2010-01-16

    The Propulsion Materials program focuses on enabling and innovative materials technologies that are critical in improving the efficiency of advanced engines. Projects within the Propulsion Materials Program address materials concerns that directly impact the critical technical barriers in each of these programs—barriers such as fuel efficiency, thermal management, emissions reduction, and reduced manufacturing costs.

  11. Advanced High-Temperature Engine Materials Technology Progresses

    Science.gov (United States)

    1997-01-01

    The objective of the Advanced High Temperature Engine Materials Technology Program (HITEMP) at the NASA Lewis Research Center is to generate technology for advanced materials and structural analysis that will increase fuel economy, improve reliability, extend life, and reduce operating costs for 21st century civil propulsion systems. The primary focus is on fan and compressor materials (polymer-matrix composites - PMC's), compressor and turbine materials (superalloys, and metal-matrix and intermetallic-matrix composites - MMC's and IMC's), and turbine materials (ceramic-matrix composites - CMC's). These advanced materials are being developed in-house by Lewis researchers and on grants and contracts.

  12. Band engineering in a van der Waals heterostructure using a 2D polar material and a capping layer

    Science.gov (United States)

    Cho, Sung Beom; Chung, Yong-Chae

    2016-06-01

    Van der Waals (vdW) heterostructures are expected to play a key role in next-generation electronic and optoelectronic devices. In this study, the band alignment of a vdW heterostructure with 2D polar materials was studied using first-principles calculations. As a model case study, single-sided fluorographene (a 2D polar material) on insulating (h-BN) and metallic (graphite) substrates was investigated to understand the band alignment behavior of polar materials. Single-sided fluorographene was found to have a potential difference along the out-of-plane direction. This potential difference provided as built-in potential at the interface, which shift the band alignment between h-BN and graphite. The interface characteristics were highly dependent on the interface terminations because of this built-in potential. Interestingly, this band alignment can be modified with a capping layer of graphene or BN because the capping layer triggered electronic reconstruction near the interface. This is because the bonding nature is not covalent, but van der Waals, which made it possible to avoid Fermi-level pinning at the interface. The results of this study showed that diverse types of band alignment can be achieved using polar materials and an appropriate capping layer.

  13. Special Purpose Materials annual progress report, October 1, 1979

    International Nuclear Information System (INIS)

    The scope of Special Purpose Materials covers fusion reactor materials problems other than the first-wall and blanket structural materials, which are under the purview of the ADIP, DAFS, and PMI task groups. Components that are considered as special purpose materials include breeding materials, coolants, neutron multipliers, barriers for tritium control, materials for compression and OH coils and waveguides, graphite and SiC, heat-sink materials, ceramics, and materials for high-field (> 10-T) superconducting magnets. It is recognized that there will be numerous materials problems that will arise during the design and construction of large magnetic-fusion energy devices such as the Engineering Test Facility (ETF) and Demonstration Reactor (DEMO). Most of these problems will be specific to a particular design or project and are the responsibility of the project, not the Materials and Radiation Effects Branch. Consequently, the Task Group on Special Purpose Materials has limited its concern to crucial and generic materials problems that must be resolved if magnetic-fusion devices are to succeed. Important areas specifically excluded include low-field (8-T) superconductors, fuels for hybrids, and materials for inertial-confinement devices. These areas may be added in the future when funding permits

  14. Chemistry and materials science progress report, FY 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    Research is reported in the areas of surface science, fundamentals of the physics and processing of metals, energetic materials, transactinide materials and properties and other indirectly related areas of weapons research.

  15. FY2008 Annual Progress Report for Propulsion Materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2009-01-01

    This program focuses on enabling and innovative materials technologies that are critical in improving the efficiency of advanced engines providing enabling materials support for combustion, hybrid, and power electronics development.

  16. FY2010 Annual Progress Report for Propulsion Materials

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Patrick B. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Schutte, Carol L. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Gibbs, Jerry L. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2011-01-01

    The Propulsion Materials Technology actively supports the energy security and reduction of greenhouse emissions goals of the Vehicle Technologies Program by developing advanced materials that enable development of higher efficiency powertrains for ground transportation. Propulsion Materials works closely with the other disciplines within the VT Program to identify the materials properties essential for the development of cost-effective, highly efficient, and environmentally friendly next-generation heavy and light duty powertrains.

  17. Recent Progress in Magntic Regenerator Materials and Their Application

    Science.gov (United States)

    Hashimoto, Takasu

    Our group have investigated applications of magnetic materials to refrigeration technology since 1978. We have verified that the heavy rare earth magnetic materials are very effective and useful as the regenerator material. Therefore, in the present articles I will describe the developing process of the magnetic regenerator materials briefly and will show the recenttopics. First,I will present the guideline for selecting the magnetic materials and show some typical examples of the specific heats of the promising materials. Next, I will indicate the superiority of the magnetic material from the comparison between the characteristics of the Pb regenerator and the Er3Ni magnetic regenerator. Then, in order to obtain the large refrigeration power at low temperature we have developed two layer type of magnetic regenerators which is the simplest model of the multi-layered magnetic regenerator. We will explain the developing process of those regenerators and their characteristics. Last, we will discuss briefly the advaning way of magnetic regenerator.

  18. Quantum Unfolding: A program for unfolding electronic energy bands of materials

    Science.gov (United States)

    Zheng, Fawei; Zhang, Ping; Duan, Wenhui

    2015-04-01

    We present Quantum Unfolding, a Fortran90 program for unfolding first-principles electronic energy bands. It unfolds energy bands accurately by handling the Fourier components of Bloch wavefunctions, which are reconstructed from Wannier functions from Wannier90. Due to the wide application of Wannier90 package and the possibility of focusing only on the most important energy bands, the present code works very conveniently.

  19. Low-Temperature Synthesis of Bismuth Chalcohalides: Candidate Photovoltaic Materials with Easily, Continuously Controllable Band gap

    Science.gov (United States)

    Kunioku, Hironobu; Higashi, Masanobu; Abe, Ryu

    2016-09-01

    Although bismuth chalcohalides, such as BiSI and BiSeI, have been recently attracting considerable attention as photovoltaic materials, the methods available to synthesize them are quite limited thus far. In this study, a novel, facile method to synthesize these chalcohalides, including BiSBr1-xIx solid solutions, at low temperatures was developed via the substitution of anions from O2- to S2- (or Se2-) using bismuth oxyhalide precursors. Complete phase transition was readily observed upon treatment of BiOI particles with H2S or H2Se at surprisingly low temperatures of less than 150 °C and short reaction times of less than 1 h, producing BiSI and BiSeI particles, respectively. This method was also applied for synthesizing BiSBr1-xIx, where continuous changes in their band gaps were observed depending on the ratio between iodine and bromine. The composition of all elements (except oxygen) in the chalcohalides thus produced was almost identical to that of the oxyhalide precursors, attributed to the suppressed volatilization of halogens at such low temperatures. All chalcohalides loaded on FTO clearly exhibited an anodic photocurrent in an acetonitrile solution containing I-, attributed to their n-type nature, e.g., the BiSI electrode exhibited high IPCE (64% at 700 nm, +0.2 V vs. Ag/AgCl).

  20. Low-Temperature Synthesis of Bismuth Chalcohalides: Candidate Photovoltaic Materials with Easily, Continuously Controllable Band gap

    Science.gov (United States)

    Kunioku, Hironobu; Higashi, Masanobu; Abe, Ryu

    2016-09-01

    Although bismuth chalcohalides, such as BiSI and BiSeI, have been recently attracting considerable attention as photovoltaic materials, the methods available to synthesize them are quite limited thus far. In this study, a novel, facile method to synthesize these chalcohalides, including BiSBr1‑xIx solid solutions, at low temperatures was developed via the substitution of anions from O2‑ to S2‑ (or Se2‑) using bismuth oxyhalide precursors. Complete phase transition was readily observed upon treatment of BiOI particles with H2S or H2Se at surprisingly low temperatures of less than 150 °C and short reaction times of less than 1 h, producing BiSI and BiSeI particles, respectively. This method was also applied for synthesizing BiSBr1‑xIx, where continuous changes in their band gaps were observed depending on the ratio between iodine and bromine. The composition of all elements (except oxygen) in the chalcohalides thus produced was almost identical to that of the oxyhalide precursors, attributed to the suppressed volatilization of halogens at such low temperatures. All chalcohalides loaded on FTO clearly exhibited an anodic photocurrent in an acetonitrile solution containing I‑, attributed to their n-type nature, e.g., the BiSI electrode exhibited high IPCE (64% at 700 nm, +0.2 V vs. Ag/AgCl).

  1. Obtaining an intermediate band photovoltaic material through the Bi insertion in CdTe

    OpenAIRE

    Seminóvski Pérez, Yohanna; Palacios Clemente, Pablo; Wahnón Benarroch, Perla

    2013-01-01

    Defect interaction can take place in CdTe under Te and Bi rich conditions. We demonstrate in this work through first principles calculations, that this phenomenon allows a Jahn Teller distortion to form an isolated half-filled intermediate band in the host semiconductor band-gap. This delocalized energy band supports the experimental deep level reported in the host band-gap of CdTe at a low bismuth concentration. Furthermore, the calculated optical absorption of CdTe:Bi in this work shows a s...

  2. Advanced Industrial Materials Program. Annual progress report, FY 1993

    Energy Technology Data Exchange (ETDEWEB)

    Stooksbury, F. [comp.

    1994-06-01

    Mission of the AIM program is to commercialize new/improved materials and materials processing methods that will improve energy efficiency, productivity, and competitiveness. Program investigators in the DOE national laboratories are working with about 100 companies, including 15 partners in CRDAs. Work is being done on intermetallic alloys, ceramic composites, metal composites, polymers, engineered porous materials, and surface modification. The program supports other efforts in the Office of Industrial Technologies to assist the energy-consuming process industries. The aim of the AIM program is to bring materials from basic research to industrial application to strengthen the competitive position of US industry and save energy.

  3. FY2014 Propulsion Materials R&D Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-05-01

    The Propulsion Materials Program actively supports the energy security and reduction of greenhouse emissions goals of VTO by investigating and identifying the materials properties that are most essential for continued development of cost-effective, highly efficient, and environmentally friendly next-generation heavy and light-duty powertrains. The technical approaches available to enhance propulsion systems focus on improvements in both vehicle efficiency and fuel substitution, both of which must overcome the performance limitations of the materials currently in use. Propulsion Materials Program activities work with national laboratories, industry experts, and VTO powertrain systems (e.g., Advanced Combustion Engines [ACE], Advanced Power Electronics and Electrical Machines [APEEM], and fuels) teams to develop strategies that overcome materials limitations in future powertrain performance. The technical maturity of the portfolio of funded projects ranges from basic science to subsystem prototype validation. Projects within a Propulsion Materials Program activity address materials concerns that directly impact critical technology barriers within each of the above programs, including barriers that impact fuel efficiency, thermal management, emissions reduction, improved reliability, and reduced manufacturing costs. The program engages only the barriers that result from material property limitations and represent fundamental, high-risk materials issues.

  4. FY2013 Lightweight Materials R&D Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-02-01

    As part of the U.S. Department of Energy’s (DOE’s) Vehicle Technologies Program (VTO), the Lightweight Materials (LM) activity focuses on the development and validation of advanced materials and manufacturing technologies to significantly reduce light and heavy duty vehicle weight without compromising other attributes such as safety, performance, recyclability, and cost.

  5. FY2010 Annual Progress Report for Lightweighting Materials

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-01-15

    The Lightweight Materials activity (LM) within the Vehicle Technologies Program focuses on the development and validation of advanced materials and manufacturing technologies to significantly reduce light and heavy duty vehicle weight without compromising other attributes such as safety, performance, recyclability, and cost.

  6. FY2014 Lightweight Materials R&D Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-03-01

    The Lightweight Materials research and development (R&D) area within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research focuses on addressing critical barriers to commercializing lightweight materials for passenger and commercial vehicles.

  7. Synchrotron Studies of Narrow Band and Low-Dimensional Materials. Final Report for July 1, 1990 --- December 31, 2002

    International Nuclear Information System (INIS)

    This report summarizes a 12-year program of various kinds of synchrotron spectroscopies directed at the electronic structures of narrow band and low-dimensional materials that display correlated electron behaviors such as metal-insulator transitions, mixed valence, superconductivity, Kondo moment quenching, heavy Fermions, and non-Fermi liquid properties

  8. Advanced Industrial Materials (AIM) Program: Annual progress report FY 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    In many ways, the Advanced Industrial Materials (AIM) Program underwent a major transformation in Fiscal Year 1995 and these changes have continued to the present. When the Program was established in 1990 as the Advanced Industrial Concepts (AIC) Materials Program, the mission was to conduct applied research and development to bring materials and processing technologies from the knowledge derived from basic research to the maturity required for the end use sectors for commercialization. In 1995, the Office of Industrial Technologies (OIT) made radical changes in structure and procedures. All technology development was directed toward the seven ``Vision Industries`` that use about 80% of industrial energy and generated about 90% of industrial wastes. The mission of AIM has, therefore, changed to ``Support development and commercialization of new or improved materials to improve productivity, product quality, and energy efficiency in the major process industries.`` Though AIM remains essentially a National Laboratory Program, it is essential that each project have industrial partners, including suppliers to, and customers of, the seven industries. Now, well into FY 1996, the transition is nearly complete and the AIM Program remains reasonably healthy and productive, thanks to the superb investigators and Laboratory Program Managers. This Annual Report for FY 1995 contains the technical details of some very remarkable work by the best materials scientists and engineers in the world. Areas covered here are: advanced metals and composites; advanced ceramics and composites; polymers and biobased materials; and new materials and processes.

  9. Fusion materials semiannual progress report for period ending December 31, 1999

    International Nuclear Information System (INIS)

    This is the twenty-seventh in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components

  10. Fusion materials semiannual progress report for period ending December 31, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G.

    2000-03-01

    This is the twenty-seventh in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components.

  11. Science of materials. Progress report, January 1-December 31, 1979

    International Nuclear Information System (INIS)

    The research program includes studies of the microchemistry, microstructure, deformation, corrosion and fracture of metals, ceramics and alloy materials, of the hydrogen embrittlement of metals, the mechanism of heat transfer across interfacts, catalytic properties of surfaces, and erosion of surfaces by fluid suspended particles. The structure of liquids, polymers and disordered solids is under investigation with emphasis on molecular interactions and bonding, on ionic conduction, phase transitions and radiation damage. Ferro- and pyro-electric materials with potential for solar energy applications are under development. The study of optical properties includes the mechanism of luminescence, the design of molecular photoreceptors, and new semiconductor materials for photovoltaic devices

  12. Heavy Vehicle Propulsion Materials Program: Progress and Highlights

    Energy Technology Data Exchange (ETDEWEB)

    D. Ray Johnson; Sidney Diamond

    2000-06-19

    The Heavy Vehicle Propulsion Materials Program was begun in 1997 to support the enabling materials needs of the DOE Office of Heavy Vehicle Technologies (OHVT). The technical agenda for the program grew out of the technology roadmap for the OHVT and includes efforts in materials for: fuel systems, exhaust aftertreatment, valve train, air handling, structural components, electrochemical propulsion, natural gas storage, and thermal management. A five-year program plan was written in early 2000, following a stakeholders workshop. The technical issues and planned and ongoing projects are discussed. Brief summaries of several technical highlights are given.

  13. Chemistry and Materials Science progress report, first half FY 1992

    International Nuclear Information System (INIS)

    This report contains sections on: Fundamentals of the physics and processing of metals; interfaces, adhesion, and bonding; energetic materials; plutonium research; synchrotron radiation-based materials science; atomistic approach to the interaction of surfaces with the environment: actinide studies; properties of carbon fibers; buried layer formation using ion implantation; active coherent control of chemical reaction dynamics; inorganic and organic aerogels; synthesis and characterization of melamine-formaldehyde aerogels; structural transformation and precursor phenomena in advanced materials; magnetic ultrathin films, surfaces, and overlayers; ductile-phase toughening of refractory-metal intermetallics; particle-solid interactions; electronic structure evolution of metal clusters; and nanoscale lithography induced chemically or physically by modified scanned probe microscopy

  14. Science of materials. Progress report, January 1-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    The research program includes studies of the microchemistry, microstructure, deformation, corrosion and fracture of metals, ceramics and alloy materials, of the hydrogen embrittlement of metals, the mechanism of heat transfer across interfacts, catalytic properties of surfaces, and erosion of surfaces by fluid suspended particles. The structure of liquids, polymers and disordered solids is under investigation with emphasis on molecular interactions and bonding, on ionic conduction, phase transitions and radiation damage. Ferro- and pyro-electric materials with potential for solar energy applications are under development. The study of optical properties includes the mechanism of luminescence, the design of molecular photoreceptors, and new semiconductor materials for photovoltaic devices.

  15. An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity.

    Science.gov (United States)

    Allen, Kenneth W; Scott, Mark M; Reid, David R; Bean, Jeffrey A; Ellis, Jeremy D; Morris, Andrew P; Marsh, Jeramy M

    2016-05-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10(-3) for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands. PMID:27250447

  16. Novel progress in the development of hydrogen storage materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A new dehydrogenation mechanism for LiBH4, a new hydrogen storage material, has recently been developed by CAS scientists and their coworkersfrom the University of Nottingham, showing a promising future for its onboard applications.

  17. Chemistry and Materials Science progress report, FY 1994. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    Thrust areas of the weapons-supporting research include surface science, fundamentals of the physics and processing of metals, energetic materials, etc. The laboratory directed R and D include director`s initiatives, individual projects, and transactinium science studies.

  18. Progress in materials for microelectronics and further challenges

    International Nuclear Information System (INIS)

    Development of materials and technologies for microelectronics is required by the needs of the constantly increasing level of integration of microelectronics circuits. Increase of the integration level compels down scaling of all the dimensions of devices, which in its turn requires very thin layers with exceptional quality due to rather high electric fields at working conditions. First, technological improvements are adopted aimed at fabrication of materials with uniform quality, geometrical flatness and extremely low density of intentionally introduced defects. Second, new fabrication methods are developed providing materials with much better quality. Third, new materials showing better properties than the standard (conventional) ones are obtained and developed further. Decreasing the dimensions of the layers changes the nature of the physical phenomena involved in the functioning of devices. Quantum mechanical mechanisms are more and more important in the description of the properties of the materials and devices on the nano scale. The question arises where is the limit of the possibilities of the materials and technologies for nano scale electronics. (Author)

  19. Flat band degeneracy and near-zero refractive index materials in acoustic crystals

    Directory of Open Access Journals (Sweden)

    Shiqiao Wu

    2016-01-01

    Full Text Available A Dirac-like cone is formed by utilizing the flat bands associated with localized modes in an acoustic crystal (AC composed of a square array of core-shell-structure cylinders in a water host. Although the triply-degeneracy seems to arise from two almost-overlapping flat bands touching another curved band, the enlarged view of the band structure around the degenerate point reveals that there are actually two linear bands intersecting each other at the Brillouin zone center, with another flat band passing through the same crossing point. The linearity of dispersion relations is achieved by tuning the geometrical parameters of the cylindrical scatterers. A perturbation method is used to not only accurately predict the linear slopes of the dispersions, but also confirm the linearity of the bands from first principles. An effective medium theory based on coherent potential approximation is developed, and it shows that a slab made of the AC carries a near-zero refractive index around the Dirac-like point. Full-wave simulations are performed to unambiguously demonstrate the wave manipulating properties of the AC structures such as perfect transmission, unidirectional transmission and wave front shaping.

  20. Novel progress in laser welding of dissimilar materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ As the most widely used thermal power machine, the diesel engine plays a key role in today's social and economic development. Its dynamic performance could be effectively upgraded by one of its core components, the turbocharger, whose quality largely depends on welding technology for dissimilar materials.

  1. Chemistry and Materials Science. Progress report, first half, FY 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    Thrust areas of the weapons-supporting research are growth, structure, and reactivity of surfaces and thin films; uranium research; physics and processing of metals; energetic materials; etc. The laboratory-directed R and D include director`s initiatives and individual projects, and transactinium institute studies.

  2. Advanced Industrial Materials (AIM) Program annual progress report, FY 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    The Advanced Industrial Materials (AIM) Program is a part of the Office of Industrial Technologies (OIT), Energy Efficiency and Renewable Energy, US Department of Energy (DOE). The mission of AIM is to support development and commercialization of new or improved materials to improve energy efficiency, productivity, product quality, and reduced waste in the major process industries. OIT has embarked on a fundamentally new way of working with industries--the Industries of the Future (IOF) strategy--concentrating on the major process industries that consume about 90% of the energy and generate about 90% of the waste in the industrial sector. These are the aluminum, chemical, forest products, glass, metalcasting, and steel industries. OIT has encouraged and assisted these industries in developing visions of what they will be like 20 or 30 years into the future, defining the drivers, technology needs, and barriers to realization of their visions. These visions provide a framework for development of technology roadmaps and implementation plans, some of which have been completed. The AIM Program supports IOF by conducting research and development on materials to solve problems identified in the roadmaps. This is done by National Laboratory/industry/university teams with the facilities and expertise needed to develop new and improved materials. Each project in the AIM Program has active industrial participation and support.

  3. Progress in materials and technologies for ultrahigh density data storage

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the development of information superhighway, nanometer-scale data storage has been proposed and attracted great interest in recent years. This article reviews the research achievements in this field, and especially focuses on the materials for data recording by using an atomic force microscope (AFM) and scanning tunneling microscope (STM).

  4. Ab-initio vibrational properties of transition metal chalcopyrite alloys determined as high-efficiency intermediate-band photovoltaic materials

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM. Ciudad Universitaria s/n, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica, CSIC. Marie Curie 2, Cantoblanco, 28049 Madrid (Spain)], E-mail: pablop@etsit.upm.es; Aguilera, I.; Wahnon, P. [Instituto de Energia Solar and Dpt. de Tecnologias Especiales, ETSI de Telecomunicacion, UPM. Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2008-08-30

    In this work, we present frozen phonon and linear response ab-initio research into the vibrational properties of the CuGaS{sub 2} chalcopyrite and transition metal substituted (CuGaS{sub 2})M alloys. These systems are potential candidates for developing a novel solar-cell material with enhanced optoelectronic properties based in the implementation of the intermediate-band concept. We have previously carried out ab-initio calculations of the electronic properties of these kinds of chalcopyrite metal alloys showing a narrow transition metal band isolated in the semiconductor band gap. The substitutes used in the present work are the 3d metal elements, Titanium and Chromium. For the theoretical calculations we use standard density functional theory at local density and generalized gradient approximation levels. We found that the optical phonon branches of the transition metal chalcopyrite, are very sensitive to the specific bonding geometry and small changes in the transition metal environment.

  5. Materials Science Division progress report 1986-1988

    International Nuclear Information System (INIS)

    This is a report on the various Research and Developmental (R and D) activities carried out in the Materials Science Division during the period 1986-88. Most contributions have been presented in the form of abstracts and wherever possible results of several contributions on a related problem have been consolidated into one. The R and D activities covered the following areas: (1) quasicrystalline phase, (2) high temperature superconducting behaviour in metal oxides, (3) physics of colloidal suspensions, (4) behaviour of materials under high pressure, (5) radiation effects in complex alloy systems, (6) inert gas behaviour in metals, and production of crystals, particularly of volatile semiconducting compounds. The lists of publications by the members of the Division and seminars held during 1986-88 are given at the end of the report. (a uthor)

  6. Novel wide band gap materials for highly efficient thin film tandem solar cells. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Brian E.; Connor, Stephen T.; Peters, Craig H.

    2012-06-11

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949 mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV's goal in Phase I of the DOE SBIR was to (1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and (2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS

  7. Novel wide band gap materials for highly efficient thin film tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV's goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a

  8. [Research progress of Chinese herbal medicine raw materials in cosmetics].

    Science.gov (United States)

    Xie, Yan-jun; Kong, Wei-jun; Yang, Mei-hua; Yang, Shi-hai

    2015-10-01

    Advocating green, nature, environmental protection, safety and the pursuit of efficacy are the trends of cosmetics in the world. In recent years, more and more Chinese herbal extracts with mild, high safety and small irritation are applied to cosmetics as the natural additives. This has become a new hot spot. The recent application advances of Chinese medicine raw materials in cosmetics are overviewed according to their main functions. This review will provide useful references for the future development and application of Chinese medicinal herbs cosmetics. PMID:27062803

  9. [Research progress of Chinese herbal medicine raw materials in cosmetics].

    Science.gov (United States)

    Xie, Yan-jun; Kong, Wei-jun; Yang, Mei-hua; Yang, Shi-hai

    2015-10-01

    Advocating green, nature, environmental protection, safety and the pursuit of efficacy are the trends of cosmetics in the world. In recent years, more and more Chinese herbal extracts with mild, high safety and small irritation are applied to cosmetics as the natural additives. This has become a new hot spot. The recent application advances of Chinese medicine raw materials in cosmetics are overviewed according to their main functions. This review will provide useful references for the future development and application of Chinese medicinal herbs cosmetics.

  10. Software Progress in the PGNAA of Bulk Materials

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Gardner; C. W. Mayo; E. S. El Sayyed; W. Zhang

    2000-06-04

    One of the primary evolving important uses of {sup 252}Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk materials in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. This paper describes the authors' work on the development of suitable computer software for this application.

  11. Recent Progress on Nanoscale Rare Earth Luminescent Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results The size of nanoscale rare earth luminescent materials is often smaller than that of the excitement or emission wavelength,and it has amazing surface state density. Therefore,it shows a lot of new luminescent phenomena such as the shift of CTS,the broadening of emission peaks,the variation of fluorescent lifetimes and quantum efficiency,and the increase of quenching concentration.It is not only of academic interest but also of technological importance for advanced phosphor applications to rese...

  12. Radiation effects in nuclear waste materials. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Weber, W.J.; Corrales, L.R. [Pacific Northwest National Lab., Richland, WA (US); Birtcher, R.C. [Argonne National Lab., IL (US); Nastasi, M. [Los Alamos National Lab., NM (US)

    1998-06-01

    'The objective of this multidisciplinary, multi-institutional research effort is to develop a fundamental understanding of radiation effects in glasses and ceramics at the atomic, microscopic, and macroscopic levels. The goal is to provide the underpinning science and models necessary to assess the performance of glasses and ceramics designed for the immobilization and disposal of high-level tank waste, plutonium residues, excess weapons plutonium, and other highly radioactive waste streams. A variety of experimental and computer simulation methods are employed in this effort. In general, research on glasses focuses on the electronic excitations due to ionizing radiation emitted from beta decay, since this is currently thought to be the principal mechanism for deleterious radiation effects in nuclear waste glasses. Research on ceramics focuses on defects and structural changes induced by the elastic interactions between alpha-decay particles and the atoms in the structure. Radiation effects can lead to changes in physical and chemical properties that may significantly impact long-term performance of nuclear waste materials. The current lack of fundamental understanding of radiation effects in nuclear waste materials makes it impossible to extrapolate the limited existing data bases to larger doses, lower dose rates, different temperature regimes, and different glass compositions or ceramic structures. This report summarizes work after almost 2 years of a 3-year project. Work to date has resulted in 9 publications. Highlights of the research over the past year are presented.'

  13. Recent progress in hydrogen-rich materials from the perspective of bonding flexibility of hydrogen

    International Nuclear Information System (INIS)

    The bonding flexibility of hydrogen is a source of various interesting functionalities in hydrides. Here, we illustrate the benefits of this flexibility through several selected examples of recent progress in the development of hydrogen storage materials. From the viewpoint of electronegativity, we discuss the diverse cohesion and materials science underlying the bonding flexibility of hydrogen in hydrides

  14. Fusion reactor materials. Semiannual progress report for period ending September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F.; Burn, G.L.; Knee`, S.S.; Dowker, C.L. [comps.

    1994-02-01

    This is the fifteenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; Special purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the U.S. Department of Energy. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  15. Photonic band gaps in materials with triply periodic surfaces and related tubular structures

    NARCIS (Netherlands)

    Michielsen, K; Kole, JS

    2003-01-01

    We calculate the photonic band gap of triply periodic bicontinuous cubic structures and of tubular structures constructed from the skeletal graphs of triply periodic minimal surfaces. The effect of the symmetry and topology of the periodic dielectric structures on the existence and the characteristi

  16. Functionally Graded Thermoelectric Material though One Step Band Gap and Dopant Engineering

    DEFF Research Database (Denmark)

    Jensen, Ellen Marie; Borup, Kasper Andersen; Cederkrantz, Daniel;

    gradients. It has previously been shown that a large functionally graded thermoelectric single crystal can be synthesized by the Czochralski method (1). Utilizing element gradients inherent to the Czochralski process we have synthesized a Ge1-xSix:B crystal with a continuously varying x, band gap, and...

  17. Progress on laboratory studies of the immobilisation of plutonium contaminated materials (pcm)

    International Nuclear Information System (INIS)

    This report describes progress on laboratory scale investigations into immobilisation of Plutonium Contaminated Materials for the year ending August 1984. The work is a continuation of that previously reported though some new work is also included. The samples tested were shredded plastic materials and latex. Three areas of work are covered (1) ISO Leach Tests (2) Radiolysis and degradation of organic materials (3) Equilibrium Leach Tests. (author)

  18. Progress in the activities on prevention and combating of illicit trafficking of nuclear material in Lithuania

    International Nuclear Information System (INIS)

    The paper gives a general overview of the progress, which has been done in the activities on prevention and combating of illicit trafficking of nuclear material in Lithuania. It describes the measures, which were taken to strengthen nuclear material accounting and control and physical protection. The current status of the national legislation and the functions of institutions involved in control of nuclear material and combating of illicit trafficking are discussed. (author)

  19. Fusion Materials Semiannual Progress Report for Period Ending December 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliff, A.F.; Burn, G.

    1999-04-01

    This is the twenty-fifth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the U.S. Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately.

  20. Fusion Materials Semiannual Progress Report for Period Ending June 30, 2000

    Energy Technology Data Exchange (ETDEWEB)

    Berk, S.E.

    2001-02-13

    This is the twenty-eighth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the U.S. Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately.

  1. Fusion Materials Semiannual Progress Report for the Period Ending June 30, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Rowcliffe, A.F.

    1999-09-01

    This is the twenty-sixth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and its reported separately.

  2. Software progress in the PGNAA of bulk materials

    International Nuclear Information System (INIS)

    One of the primary evolving important uses of 252Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk material in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. The authors have been working on the development of suitable computer software for this application. Their primary approach has been the Monte Carlo Library Least-Squares method, in which library spectra for each element are calculated with the specific-purpose Monte Carlo code CEARPGA. These libraries are then used with experimental spectra in a standard library least-squares (LLS) approach to determine elemental amounts. Since the PGNAA response is nonlinear for these applications, one must first make an initial estimate of the sample composition. If the final calculated elemental amounts are not close enough to the initial estimate that linearity can be assumed, another iteration with a better estimate of the sample composition must be made. One of the general problems encountered in analyses of this type is the spectrum distortion introduced by the pulse pileup that occurs with light counting rates. In many applications, one desires the highest possible counting rate so that fast transient phenomena can be accurately followed. The technique of using electronic discrimination is only partially successful in that one throws away much of the data and there is some remaining distortion in the data that are kept. For this reason they developed a Monte Carlo model for the forward simulation of pulse pileup (given the true counting rate the pulse piled-up distorted spectrum is generated). The resulting computer code can give an accurate spectral result in 2 or 3 min on present personal computers. This result can either be used directly to generate model spectra that can be compared

  3. Software progress in the PGNAA of bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, R.P.; Mayo, C.W.; El Sayyed, E.S.; Zhang, W.

    2000-07-01

    One of the primary evolving important uses of {sup 252}Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk material in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. The authors have been working on the development of suitable computer software for this application. Their primary approach has been the Monte Carlo Library Least-Squares method, in which library spectra for each element are calculated with the specific-purpose Monte Carlo code CEARPGA. These libraries are then used with experimental spectra in a standard library least-squares (LLS) approach to determine elemental amounts. Since the PGNAA response is nonlinear for these applications, one must first make an initial estimate of the sample composition. If the final calculated elemental amounts are not close enough to the initial estimate that linearity can be assumed, another iteration with a better estimate of the sample composition must be made. One of the general problems encountered in analyses of this type is the spectrum distortion introduced by the pulse pileup that occurs with light counting rates. In many applications, one desires the highest possible counting rate so that fast transient phenomena can be accurately followed. The technique of using electronic discrimination is only partially successful in that one throws away much of the data and there is some remaining distortion in the data that are kept. For this reason they developed a Monte Carlo model for the forward simulation of pulse pileup (given the true counting rate the pulse piled-up distorted spectrum is generated). The resulting computer code can give an accurate spectral result in 2 or 3 min on present personal computers. This result can either be used directly to generate model spectra that can be

  4. Characterization of dielectric constant of solid materials (Leather belt at X-Band

    Directory of Open Access Journals (Sweden)

    Ambika Singh

    2016-07-01

    Full Text Available This paper discusses the experimental measurement technique for dielectric constant (i.e.permittivity of leather belt at X-band. This measurement play selection of dielectric constant for antenna substrate. This leather can be used as flexible substrate of wearable microstrip antenna. This measurement system consist of solid state klystron power supply, isolator, VSWR meter, frequency meter, solid dielectric cell (XC-501. This data may be interested in flexibility wearable microstrip antenna studies.

  5. A dual-functional asymmetric squaraine-based low band gap hole transporting material for efficient perovskite solar cells

    Science.gov (United States)

    Paek, Sanghyun; Rub, Malik Abdul; Choi, Hyeju; Kosa, Samia A.; Alamry, Khalid A.; Cho, Jin Woo; Gao, Peng; Ko, Jaejung; Asiri, Abdullah M.; Nazeeruddin, Mohammad Khaja

    2016-03-01

    We demonstrate for the first time an asymmetric squaraine-based low band-gap hole transporting material, which acted as both light harvesting and hole transporting layers in methylammonium lead triiodide perovskite solar cells. Opto-electrochemical characterization revealed extremely high molar extinction coefficients of the absorption bands in the low energy region and prominent space charge delocalization due to its electronically asymmetric nature. A suitable band alignment of the squaraine HOMO level with the valence band edge of the perovskite, and the conduction band of the TiO2 with LUMO of the perovskite allowed a cascade of hole extraction and electron injection, respectively. Red-shifted absorption was observed for both HTMs in thin films coated on the perovskite, and the optimized devices exhibited an impressive PCE of 14.7% under full sunlight illumination (100 mW cm-2, AM1.5 G). The efficiency value is comparable to that of the devices using a state-of-the-art spiro-OMeTAD hole transport layer under similar conditions. Ambient stability after 300 h revealed that 88% of the initial efficiency remained for JK-216D, and almost no change for JK-217D, indicating that the devices had good long-term stability thus suggesting that the asymmetric squaraines have great potential as a dual-functional HTM for high performance perovskite solar cells.We demonstrate for the first time an asymmetric squaraine-based low band-gap hole transporting material, which acted as both light harvesting and hole transporting layers in methylammonium lead triiodide perovskite solar cells. Opto-electrochemical characterization revealed extremely high molar extinction coefficients of the absorption bands in the low energy region and prominent space charge delocalization due to its electronically asymmetric nature. A suitable band alignment of the squaraine HOMO level with the valence band edge of the perovskite, and the conduction band of the TiO2 with LUMO of the perovskite allowed

  6. Fusion materials semiannual progress report for period ending June 30, 1997

    International Nuclear Information System (INIS)

    This is the twenty-second in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Topics covered here are: vanadium alloys; silicon carbide composites; ferritic/martensitic steels; austenitic stainless steels; insulating ceramics and optical materials; solid breeding materials; radiation effects mechanistic studies and experimental methods; dosimetry damage parameters; activation calculations; materials engineering and design requirements; irradiation facilities; test matrices; and experimental methods

  7. Extended two-temperature model for ultrafast thermal response of band gap materials upon impulsive optical excitation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Taeho [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Teitelbaum, Samuel W.; Wolfson, Johanna; Nelson, Keith A., E-mail: kanelson@mit.edu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); Kandyla, Maria [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 116-35 (Greece)

    2015-11-21

    Thermal modeling and numerical simulations have been performed to describe the ultrafast thermal response of band gap materials upon optical excitation. A model was established by extending the conventional two-temperature model that is adequate for metals, but not for semiconductors. It considers the time- and space-dependent density of electrons photoexcited to the conduction band and accordingly allows a more accurate description of the transient thermal equilibration between the hot electrons and lattice. Ultrafast thermal behaviors of bismuth, as a model system, were demonstrated using the extended two-temperature model with a view to elucidating the thermal effects of excitation laser pulse fluence, electron diffusivity, electron-hole recombination kinetics, and electron-phonon interactions, focusing on high-density excitation.

  8. Extended two-temperature model for ultrafast thermal response of band gap materials upon impulsive optical excitation.

    Science.gov (United States)

    Shin, Taeho; Teitelbaum, Samuel W; Wolfson, Johanna; Kandyla, Maria; Nelson, Keith A

    2015-11-21

    Thermal modeling and numerical simulations have been performed to describe the ultrafast thermal response of band gap materials upon optical excitation. A model was established by extending the conventional two-temperature model that is adequate for metals, but not for semiconductors. It considers the time- and space-dependent density of electrons photoexcited to the conduction band and accordingly allows a more accurate description of the transient thermal equilibration between the hot electrons and lattice. Ultrafast thermal behaviors of bismuth, as a model system, were demonstrated using the extended two-temperature model with a view to elucidating the thermal effects of excitation laser pulse fluence, electron diffusivity, electron-hole recombination kinetics, and electron-phonon interactions, focusing on high-density excitation. PMID:26590551

  9. Fusion reactor materials semiannual progress report for the period ending March 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This is the fourteenth in a series of semiannual technical progress reports on fusion reactor materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Depart of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Separate abstracts were prepared for each individual section.

  10. Fusion materials semiannual progress report for the period ending June 30, 1998

    International Nuclear Information System (INIS)

    This is the twenty-fourth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database

  11. Fusion reactor materials: Semiannual progress report for the period ending March 31, 1987

    International Nuclear Information System (INIS)

    This is the second in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities in the following areas: (1) Alloy Development for Irradiation Performance; (2) Damage Analysis and Fundamental Studies; and (3) Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. Separate analytics were prepared for the reports in this volume

  12. Fusion materials semiannual progress report for the period ending June 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G. [ed.] [comp.

    1998-09-01

    This is the twenty-fourth in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  13. Fusion reactor materials: Semiannual progress report for the period ending March 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1987-09-01

    This is the second in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities in the following areas: (1) Alloy Development for Irradiation Performance; (2) Damage Analysis and Fundamental Studies; and (3) Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. Separate analytics were prepared for the reports in this volume.

  14. Fusion reactor materials semiannual progress report for the period ending March 31, 1993

    International Nuclear Information System (INIS)

    This is the fourteenth in a series of semiannual technical progress reports on fusion reactor materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Depart of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. Separate abstracts were prepared for each individual section

  15. An X-Band Waveguide Measurement Technique for the Accurate Characterization of Materials with Low Dielectric Loss Permittivity

    CERN Document Server

    Allen, Kenneth W; Reid, David R; Bean, Jeffrey A; Ellis, Jeremy D; Morris, Andrew P; Marsh, Jeramy M

    2016-01-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically-long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10e-3 for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. ...

  16. Progress report for 1982/83 from the Plutonium Contaminated Materials Working Party

    International Nuclear Information System (INIS)

    The report falls under the headings: introduction (definitions of plutonium contaminated materials (PCM)); organisation and role of the Plutonium Contaminated Materials Working Party; management practices in relation to PCM; 1982/1983 Progress Report (engineering objectives; reduction of PCM arisings; plutonium measurement; development of treatment processes; decommissioning and non-combustible PCM treatment; washing of shredded combustible PCM; PCM immobilisation; liquid effluent treatment; actinide chemistry); programme management. (U.K.)

  17. Plutonium contaminated materials research programme. Progress Report for 1983/84 from the Plutonium Contaminated Materials Working Party

    International Nuclear Information System (INIS)

    Plutonium contaminated material (PCM) is a generic term applied to a wide variety of materials which have become contaminated by plutonium compounds, by virtue of their use inside the primary containment of fuel cycle plants, but which generally have low beta gamma content. The report falls under the headings: introduction; organisation and role of the PCMWP; management practices; 1983/84 progress report (a) reduction of arisings; (b) plutonium measurement; (c) treatment of solid PCM; (d) treatment of alpha bearing liquid wastes; (e) actinide chemistry; (f) engineering objectives. (U.K.)

  18. Development of high band gap materials for tandem solar cells and simulation studies on mechanical tandem solar cells

    Science.gov (United States)

    Vijayakumar, Vishnuvardhanan

    Development of low cost, high efficiency tandem solar cells is essential for large scale adoption of solar energy especially in densely populated regions of the world. In this thesis four-terminal mechanical (stack like) tandem solar cells were evaluated using detailed simulation models and design criteria for selecting candidate materials were established. Since silicon solar cells are low cost and have a multi-giga watt global manufacturing and supply chain capacity already in place then only tandem stacks incorporating silicon as one of the layers in the device was investigated. Two candidate materials which have high band gaps that could be used as top cells in the mechanical tandem device were explored as part of the thesis. Dye-sensitized solar cells (DSSC) sensitized with N719 dye (one of the candidates for the top cell) were fabricated with the goal of enabling a flexible processing path to lower cost. Stainless steel (SS) mesh substrates were used to fabricate anodes for flexible DSSC in order to evaluate them as replacements for more expensive Transparent Conducting Oxides (TCO's). Loss mechanisms in DSSC's due to SS mesh oxidation were quantified and protective coatings to prevent oxidation of SS mesh were developed. The second material which was evaluated for use as the top cell was copper zinc tin sulfide (CZTS). CZTS was deposited through a solution deposition route. Detailed investigations were done on the deposited films to understand the chemistry, crystal structure and its opto-electronic properties. Deposited CZTS films were found to be highly crystalline in direction. The films had a direct band gap of 1.5 eV with absorption coefficient greater than 104 cm -1 in agreement with published values. In the second part of the thesis detailed electrical and optical simulation models of the mechanical tandem solar cells were developed based on the most up-to-date materials physical constants available for each layer. The modeling was used to quantify

  19. Metals and ceramics division materials science program. Aunnual progress report for period ending June 30, 1979

    International Nuclear Information System (INIS)

    Progress is reported concerning theoretical studies of metals and alloys, deformation and mechanical properties, physical properties and transport phenomena, radiation effects, and engineering materials. During this period emphasis was shifted from support of nuclear technologies to support of nonnuclear energy systems

  20. Progress report for 1986 from the Plutonium Contaminated Materials Working Party

    International Nuclear Information System (INIS)

    The paper covers progress during 1986 under the joint BNFL/MOD/DoE funded PCM Working Party studying the management, treatment and immobilization of plutonium contaminated materials. Development is reported under each of seven main programme headings including reduction of arisings, Pu measurement, decommissioning and non-combustible PCM treatment, liquid effluent treatment, sorting and packaging, PCM immobilisation and engineering objectives. (author)

  1. Metals and ceramics division materials science program. Aunnual progress report for period ending June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.

    1979-10-01

    Progress is reported concerning theoretical studies of metals and alloys, deformation and mechanical properties, physical properties and transport phenomena, radiation effects, and engineering materials. During this period emphasis was shifted from support of nuclear technologies to support of nonnuclear energy systems. (FS)

  2. Evaluation of shock mitigating materials in a V-band pyroshock environment simulated with a resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, V.I.; Brown, F.A.

    1993-12-31

    An explosively activated V-band joint is used on a multistage rocket payload to release components at prescribed times in the rocket`s flight and creates a pyroshock environment that the other payload components must survive. Accelerometer response data was measured close to an actual V-band pyroshock. With the shock spectra calculated from these data, a resonant fixture was designed to simulate a V-band pyroshock event. The characteristics of the data and the design process are described. Laboratory tests were conducted to determine that the desired shock spectra with an unusually high knee at about 8,000 Hz. was produced with the resonant fixture. The fixture was then mounted on a 29 in. diameter, 2 in. thick plate simulation of a payload plate. Simulated electronic components were also mounted on the plate. The pyroshock environment simulation was created by the resonant fixture response to a projectile impact, and the component response to the environment was measured at the electronic components. The component responses to the pyroshock were measured with five different shock mitigating materials inserted between the resonant fixture and the payload plate simulation, and the peak response values were tabulated.

  3. A contribution to the development of wide band-gap nonlinear optical laser materials

    Science.gov (United States)

    Stone-Sundberg, Jennifer Leigh

    The primary focus of this work is on examining structure-property relationships of interest for high-power nonlinear optical and laser crystals. An intuitive and simply illustrated method for assessing the nonlinear optical potential of structurally characterized noncentrosymmetric materials is introduced. This method is applied to materials including common quartz and tourmaline and then extended to synthetic materials including borates, silicates, aluminates, and phosphates. Particularly, the contributions of symmetric tetrahedral and triangular anionic groups are inspected. It is shown that both types of groups significantly contribute to the optical frequency converting abilities of noncentrosymmetric crystals. In this study, several known materials are included as well as several new materials. The roles of the orientation, composition, and packing density of these anionic groups are also discussed. The structures and optical properties of the known materials BPO 4, NaAlO2, LaCa4O(BO3)3, and tourmaline; the new compounds La0.8Y0.2Sc3 (BO3)4 and Ba2B10O 17; and the laser host Sr3Y0.75Yb0.25(BO 3)3 are described.

  4. 塑封材料研究进展%The Research Progress On Plastic Packaging Material

    Institute of Scientific and Technical Information of China (English)

    武祥

    2012-01-01

    综述了常用塑封树脂和塑封填充材料的最新进展,概述了常用塑封树脂和塑封填充材料的应用特征,讨论了需要关注的重点方向。%The recent progress for Plastic Packaging Material technology is introduced.The structure,properties and application of Plastic Packaging Material are investigated.Plastic Packaging Material and its process features are reviewed.

  5. Research progress on thermal protection materials and structures of hypersonic vehicles

    Institute of Scientific and Technical Information of China (English)

    YANG Ya-zheng; YANG Jia-ling; FANG Dai-ning

    2008-01-01

    Hypersonic vehicles represent future trends of military equipments and play an important role in future war. Thermal protection materials and structures, which relate to the safety of hypersonic vehicles, are one of the most key techniques in design and manufacture of hypersonic vehicles. Among these materials and structures, such as metallic temperature protection structure, the temperature ceramics and carbon/carbon composites are usually adopted in design. The recent progresses of research and applica- tion of ultra-high temperature materials in preparation, oxidation resistance, mechanical and physical characterization are summarized.

  6. Fusion Reactor Materials semiannual progress report for the period ending March 31, 1992

    International Nuclear Information System (INIS)

    This is the twelfth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  7. Fusion materials semiannual progress report for the period ending March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This is the eighteenth in a series of semiannual technical progress reports on fusion materials. This report combines research and development activities which were previously reported separately in the following progress reports: {sm_bullet} Alloy Development for Irradiation Performance. {sm_bullet} Damage Analysis and Fundamental Studies. {sm_bullet} Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide. This report has been compiled and edited under the guidance of A.F. Rowcliffe by Gabrielle Burn, Oak Ridge National Laboratory. Their efforts, and the efforts of the many persons who made technical contributions, are gratefully acknowledged.

  8. Fusion reactor materials: Semiannual progress report for period ending September 30, 1987

    International Nuclear Information System (INIS)

    This is the third in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development for Irradiation Performances; Damage Analysis and Fundamental Studies; Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  9. Fusion reactor materials semiannual progress report for period ending September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    This is the ninth in series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development of Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  10. Fusion reactor materials semiannual progress report for the period ending March 31, 1991

    International Nuclear Information System (INIS)

    This is the tenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: alloy development for irradiation performance; damage analysis and fundamental studies; special purpose materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of program participants, and to provide a means of communicating the efforts of materials scientists to the test of the fusion community, both nationally and worldwide

  11. Fusion reactor materials semiannual progress report for period ending September 30, 1990

    International Nuclear Information System (INIS)

    This is the ninth in series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development of Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  12. Fusion materials semiannual progress report for the period ending March 31, 1995

    International Nuclear Information System (INIS)

    This is the eighteenth in a series of semiannual technical progress reports on fusion materials. This report combines research and development activities which were previously reported separately in the following progress reports: sm-bullet Alloy Development for Irradiation Performance. sm-bullet Damage Analysis and Fundamental Studies. sm-bullet Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide. This report has been compiled and edited under the guidance of A.F. Rowcliffe by Gabrielle Burn, Oak Ridge National Laboratory. Their efforts, and the efforts of the many persons who made technical contributions, are gratefully acknowledged

  13. Fusion reactor materials semiannual progress report for the period ending September 30, 1989

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-01-01

    This is the seventh in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: alloy development for irradiation performance, damage analysis and fundamental studies, and special purpose materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  14. Fusion reactor materials: Semiannual progress report for period ending September 30, 1987

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1988-03-01

    This is the third in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following technical progress reports: Alloy Development for Irradiation Performances; Damage Analysis and Fundamental Studies; Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  15. Fusion Reactor Materials semiannual progress report for the period ending March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    This is the twelfth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; and Special Purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide.

  16. Method for implantation of high dopant concentrations in wide band gap materials

    Energy Technology Data Exchange (ETDEWEB)

    Usov, Igor (Los Alamos, NM); Arendt, Paul N. (Los Alamos, NM)

    2009-09-15

    A method that combines alternate low/medium ion dose implantation with rapid thermal annealing at relatively low temperatures. At least one dopant is implanted in one of a single crystal and an epitaxial film of the wide band gap compound by a plurality of implantation cycles. The number of implantation cycles is sufficient to implant a predetermined concentration of the dopant in one of the single crystal and the epitaxial film. Each of the implantation cycles includes the steps of: implanting a portion of the predetermined concentration of the one dopant in one of the single crystal and the epitaxial film; annealing one of the single crystal and the epitaxial film and implanted portion at a predetermined temperature for a predetermined time to repair damage to one of the single crystal and the epitaxial film caused by implantation and activates the implanted dopant; and cooling the annealed single crystal and implanted portion to a temperature of less than about 100.degree. C. This combination produces high concentrations of dopants, while minimizing the defect concentration.

  17. Beyond Graphene: Progress in Novel Two-Dimensional Materials and van der Waals Solids

    Science.gov (United States)

    Das, Saptarshi; Robinson, Joshua A.; Dubey, Madan; Terrones, Humberto; Terrones, Mauricio

    2015-07-01

    Interest in 2D materials and van der Waals solids is growing exponentially across various scientific and engineering disciplines owing to their fascinating electrical, optical, chemical, and thermal properties. Whereas the micromechanical exfoliation technique has been adopted for rapid material characterization and demonstration of innovative device ideas based on these 2D systems, significant advances have recently been made in large-scale homogeneous and heterogeneous growth of these materials. This review reflects recent progress and outlines future prospects of these novel 2D materials. We provide a holistic overview of the different synthesis and characterization techniques, electronic and photonic device characteristics, and catalytic properties of transition metal dichalcogenides and their heterostructures. We also comment on the challenges that need to be overcome for full-scale commercial implementation of this novel class of layered materials.

  18. Fusion materials semiannual progress report for the period ending December 31, 1996

    International Nuclear Information System (INIS)

    This is the twenty-first in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The report covers the following topics: vanadium alloys; silicon carbide composite materials; ferritic/martensitic steels; copper alloys and high heat flux materials; austenitic stainless steels; insulating ceramics and optical materials; solid breeding materials; radiation effects, mechanistic studies and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; and irradiation facilities, test matrices, and experimental methods

  19. Fusion materials semiannual progress report for the period ending December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This is the twenty-first in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The report covers the following topics: vanadium alloys; silicon carbide composite materials; ferritic/martensitic steels; copper alloys and high heat flux materials; austenitic stainless steels; insulating ceramics and optical materials; solid breeding materials; radiation effects, mechanistic studies and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; and irradiation facilities, test matrices, and experimental methods.

  20. Realizing high figure of merit in heavy-band p-type half-Heusler thermoelectric materials

    Science.gov (United States)

    Fu, Chenguang; Bai, Shengqiang; Liu, Yintu; Tang, Yunshan; Chen, Lidong; Zhao, Xinbing; Zhu, Tiejun

    2015-09-01

    Solid-state thermoelectric technology offers a promising solution for converting waste heat to useful electrical power. Both high operating temperature and high figure of merit zT are desirable for high-efficiency thermoelectric power generation. Here we report a high zT of ~1.5 at 1,200 K for the p-type FeNbSb heavy-band half-Heusler alloys. High content of heavier Hf dopant simultaneously optimizes the electrical power factor and suppresses thermal conductivity. Both the enhanced point-defect and electron-phonon scatterings contribute to a significant reduction in the lattice thermal conductivity. An eight couple prototype thermoelectric module exhibits a high conversion efficiency of 6.2% and a high power density of 2.2 W cm-2 at a temperature difference of 655 K. These findings highlight the optimization strategy for heavy-band thermoelectric materials and demonstrate a realistic prospect of high-temperature thermoelectric modules based on half-Heusler alloys with low cost, excellent mechanical robustness and stability.

  1. Nanosized Ce–Zn substituted microwave absorber material for X-band applications

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq, Imran, E-mail: khanphysics@yahoo.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ali, Irshad [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Rebrov, Evgeny [School of Chemistry and Chemical Engineering, Queen' s University Belfast (United Kingdom); Naseem, Shahzad [Center for Solid State Physics, University of the Punjab, Lahore (Pakistan); Ashiq, M. Naeem [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Rana, M.U., E-mail: mazharrana@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2014-12-15

    The sol–gel autocombustion method has been used to synthesize the Ce–Zn substituted with composition Sr{sub 2−x}Ce{sub x}Ni{sub 2}Fe{sub 28−y}Zn{sub y}O{sub 46} (x=0.02, 0.04, 0.06, 0.08, 0.010 and y=0.1, 0.2, 0.3, 0.4, 0.5) X-type hexagonal ferrites. The XRD analysis confirms the single phase of the material. The variation in lattice parameters can be observed with addition of Ce–Zn dopant. The ferrites substituted with Ce–Zn contents have low value of grain size than the unsubstituted ferrites. The crystallite size measured from TEM and HRTEM analysis was found in the range of 40–45 nm which is in good agreement with the theoretically measured by Scherer formula. The room temperature electrical resistivity lies in the range of ∼10{sup 9} Ω-cm, so the investigated sample can be considered good material for reducing the eddy current losses. The enhancement in magnetic properties (saturation magnetization, retentivity and coercivity) has been observed with the substitution of Ce–Zn contents in pure ferrites. The increment in resistivity and magnetic properties with the substitution of Ce–Zn dopant makes it important candidate to be used in the formation of multilayer chip inductors (MLCIs). The maximum reflection loss of −23.4 dB at 12.858 GHz is obtained by Ce–Zn doped ferrites and attenuation constant agrees well with the reflection loss. The microwave absorption properties of this substituted material reflect its applications in super high frequency (SHF) devices. - Highlights: • A series of X-type hexagonal ferrites were prepared by the Sol–Gel autocombustion method. • The XRD analysis showed that the X-type hexagonal structure. • The crystallite size was measured by TEM that varies from 40 to 45 nm. • Magnetic properties of the samples enhances with the substitution of the Ce–Zn dopants. • Maximum of −23.4 dB reflection loss is exhibited by Ce–Zn doped samples.

  2. Recent progress in stem cell differentiation directed by material and mechanical cues.

    Science.gov (United States)

    Lin, Xunxun; Shi, Yuan; Cao, Yilin; Liu, Wei

    2016-02-01

    Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular

  3. Recent progress in stem cell differentiation directed by material and mechanical cues.

    Science.gov (United States)

    Lin, Xunxun; Shi, Yuan; Cao, Yilin; Liu, Wei

    2016-02-02

    Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular

  4. Negative thermal expansion and broad band photoluminescence in a novel material of ZrScMo2VO12

    Science.gov (United States)

    Ge, Xianghong; Mao, Yanchao; Liu, Xiansheng; Cheng, Yongguang; Yuan, Baohe; Chao, Mingju; Liang, Erjun

    2016-04-01

    In this paper, we present a novel material with the formula of ZrScMo2VO12 for the first time. It was demonstrated that this material exhibits not only excellent negative thermal expansion (NTE) property over a wide temperature range (at least from 150 to 823 K), but also very intense photoluminescence covering the entire visible region. Structure analysis shows that ZrScMo2VO12 has an orthorhombic structure with the space group Pbcn (No. 60) at room temperature. A phase transition from monoclinic to orthorhombic structure between 70 and 90 K is also revealed. The intense white light emission is tentatively attributed to the n- and p-type like co-doping effect which creates not only the donor- and acceptor-like states in the band gap, but also donor-acceptor pairs and even bound exciton complexes. The excellent NTE property integrated with the intense white-light emission implies a potential application of this material in light emitting diode and other photoelectric devices.

  5. Synthesis and energy band characterization of hybrid molecular materials based on organic–polyoxometalate charge-transfer salts

    International Nuclear Information System (INIS)

    A cationic amphiphilic molecule was synthesized and employed to encapsulate Lindqvist ([M6O19]2−) and Keggin polyoxometalates ([SiM12O40]4−, M=Mo, W) to form hybrid molecules through electrostatic interaction. The X-ray diffraction results illustrate that the former hybrids possess lamellar nanostructures in their solid states, while the latter hybrids show a cubic Im3m packing model with low intensities and poor long-range order. These hybrids have clear charge-transfer characters as shown in their deeper colors and UV–vis diffuse reflectance spectra. According to the reported reduction potentials of the POM acceptors and the band gaps deduced from their diffuse reflectance spectra, we have calculated the theoretical values of the lowest unoccupied molecular orbital (LUMO) position similar to the electron affinity (EA) of solid materials. Such energy level parameters are comparable to those of electroluminescence and electron-transport materials commonly used in organic electroluminescence devices. These organic–polyoxometalate charge-transfer salts have more advantages, such as higher decomposition temperatures, easier film fabrication and better electron affinities, which presumably would be used for electron-transport materials in the area of the electroluminescence. - Graphical abstract: Hybrid molecular materials with charge-transfer characters formed by a positively charged donor L and acceptors of the Lindqvist-type and Keggin-type POMs have lamellar and cubic structures in their solid state. - Highlights: • Charge-transfer salts are obtained by self-assembling POMs with an anthracene cation. • Their energy parameters are comparable to those of optoelectronic materials in OLEDs. • These POM-based hybrids could be applied in the area of optoelectronic devices

  6. Synthesis and energy band characterization of hybrid molecular materials based on organic–polyoxometalate charge-transfer salts

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Chunxia [Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou City, Gansu Province (China); Traditional Chinese Medicine College of Gansu, Gansu (China); Bu, Weifeng, E-mail: buwf@lzu.edu.cn [Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou City, Gansu Province (China)

    2014-11-15

    A cationic amphiphilic molecule was synthesized and employed to encapsulate Lindqvist ([M{sub 6}O{sub 19}]{sup 2−}) and Keggin polyoxometalates ([SiM{sub 12}O{sub 40}]{sup 4−}, M=Mo, W) to form hybrid molecules through electrostatic interaction. The X-ray diffraction results illustrate that the former hybrids possess lamellar nanostructures in their solid states, while the latter hybrids show a cubic Im3m packing model with low intensities and poor long-range order. These hybrids have clear charge-transfer characters as shown in their deeper colors and UV–vis diffuse reflectance spectra. According to the reported reduction potentials of the POM acceptors and the band gaps deduced from their diffuse reflectance spectra, we have calculated the theoretical values of the lowest unoccupied molecular orbital (LUMO) position similar to the electron affinity (E{sub A}) of solid materials. Such energy level parameters are comparable to those of electroluminescence and electron-transport materials commonly used in organic electroluminescence devices. These organic–polyoxometalate charge-transfer salts have more advantages, such as higher decomposition temperatures, easier film fabrication and better electron affinities, which presumably would be used for electron-transport materials in the area of the electroluminescence. - Graphical abstract: Hybrid molecular materials with charge-transfer characters formed by a positively charged donor L and acceptors of the Lindqvist-type and Keggin-type POMs have lamellar and cubic structures in their solid state. - Highlights: • Charge-transfer salts are obtained by self-assembling POMs with an anthracene cation. • Their energy parameters are comparable to those of optoelectronic materials in OLEDs. • These POM-based hybrids could be applied in the area of optoelectronic devices.

  7. A multicontinuum progressive damage model for composite materials motivated by the kinetic theory of fracture

    Science.gov (United States)

    Schumacher, Shane Christian

    2002-01-01

    A conventional composite material for structural applications is composed of stiff reinforcing fibers embedded in a relatively soft polymer matrix, e.g. glass fibers in an epoxy matrix. Although composites have numerous advantages over traditional materials, the presence of two vastly different constituent materials has confounded analysts trying to predict failure. The inability to accurately predict the inelastic response of polymer based composites along with their ultimate failure is a significant barrier to their introduction to new applications. Polymer based composite materials also tend to exhibit rate and time dependent failure characteristics. Lack of knowledge about the rate dependent response and progressive failure of composite structures has led to the current practice of designing these structures with static properties. However, high strain rate mechanical properties can vary greatly from the static properties. The objective of this research is to develop a finite element based failure analysis tool for composite materials that incorporates strain rate hardening effects in the material failure model. The analysis method, referred to as multicontinuum theory (MCT) retains the identity of individual constituents by treating them as separate but linked continua. Retaining the constituent identities allows one to extract continuum phase averaged stress/strain fields for the constituents in a routine structural analysis. Time dependent failure is incorporated in MCT by introducing a continuum damage model into MCT. In addition to modeling time and rate dependent failure, the damage model is capable of capturing the nonlinear stress-strain response observed in composite materials.

  8. Fusion materials semiannual progress report for the period ending December 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G. [ed.] [comp.

    1998-03-01

    This is the twenty-third in a series of semiannual technical progress reports on fusion materials. This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. This effort forms one element of the materials program being conducted in support of the Fusion Energy Sciences Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. The Fusion Materials Program is a national effort involving several national laboratories, universities, and industries. A large fraction of this work, particularly in relation to fission reactor experiments, is carried out collaboratively with their partners in Japan, Russia, and the European Union. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  9. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    International Nuclear Information System (INIS)

    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X

  10. Fusion materials semiannual progress report for the period ending March 31, 1994

    International Nuclear Information System (INIS)

    This is the sixteenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The other major element of the program is concerned with the interactions between reactor materials and the plasma and is reported separately. This report is divided into the following areas: (1) irradiation facilities, test matrices, and experimental methods; (2) dosimetry, damage parameters, transmutation, and activation calculations; (3) materials engineering and design requirements; (4) fundamental mechanical behavior; (5) radiation effects, mechanistic studies, theory and modelings; (6) development of structural alloys; (7) solid breeding materials and beryllium; and (8) ceramics. Selected papers were indexed separately for inclusion in the Energy Science and Technology Database

  11. Review on recent progress of nanostructured anode materials for Li-ion batteries

    KAUST Repository

    Goriparti, Subrahmanyam

    2014-07-01

    This review highlights the recent research advances in active nanostructured anode materials for the next generation of Li-ion batteries (LIBs). In fact, in order to address both energy and power demands of secondary LIBs for future energy storage applications, it is required the development of innovative kinds of electrodes. Nanostructured materials based on carbon, metal/semiconductor, metal oxides and metal phosphides/nitrides/sulfides show a variety of admirable properties for LIBs applications such as high surface area, low diffusion distance, high electrical and ionic conductivity. Therefore, nanosized active materials are extremely promising for bridging the gap towards the realization of the next generation of LIBs with high reversible capacities, increased power capability, long cycling stability and free from safety concerns. In this review, anode materials are classified, depending on their electrochemical reaction with lithium, into three groups: intercalation/de-intercalation, alloy/de-alloy and conversion materials. Furthermore, the effect of nanoscale size and morphology on the electrochemical performance is presented. Synthesis of the nanostructures, lithium battery performance and electrode reaction mechanisms are also discussed. To conclude, the main aim of this review is to provide an organic outline of the wide range of recent research progresses and perspectives on nanosized active anode materials for future LIBs.

  12. Progress in long wavelength emission in fluorene-based electroluminescent blue materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    On account of the advantages of organic electroluminescent materials compared with their inorganic counterparts,the development of organic electroluminescent materials is one of the hot areas of the optoelectronic materials.Fluorene and its derivatives,which have an aromatic biphenyl structure with a wide energy gap in the backbones and high luminescent efficiency,have drawn much attention of ma-terial chemists and device physicists.However,one drawback of fluorene-based electroluminescent blue materials is that there is an occurrence of long wavelength emission after annealing the films in air or after operating organic light-emitting diodes for a long time.To clarify the origin of this long wave-length emission,the scientists at home and abroad have put forward all kinds of correlative explana-tions.Among the scientists,some thought it was caused by excimer-related species,while some others claimed that it was caused by the fluorenone of photooxdized fluorene.The corresponding solutions to this problem have also been proposed and the problem has been partially resolved in some degree.The present review summarizes and analyzes the progress made on the origin of long wavelength emission in fluorene-based electroluminescent blue materials at home and abroad in the past few years.Some issues to be addressed and hotspots to be further investigated are also presented and discussed.

  13. Optoelectronic Characterization by Advanced Ab-Initio Methods of Novel Photovoltaic Intermediate Band Materials = Caracterización optoelectrónica por métodos ab-initio avanzados de nuevos materiales fotovoltaicos de banda intermedia

    OpenAIRE

    Aguilera Bonet, Irene

    2010-01-01

    Intermediate-band materials represent nowadays one of the most promising proposals in the quest for more efficient, lower-cost solar cells. In this thesis we present a deep study of transition-metal substituted semiconductors based on their optoelectronic properties. These materials were proposed as high efficiency photovoltaic absorbers for intermediate-band solar cells for showing a partiallyfilled band placed inside the band gap of the parent semiconductor which enables the absorption of p...

  14. Heterogeneous integration of semiconductor materials: basic issues, current progress, and future prospects

    Science.gov (United States)

    Woodall, Jerry M.

    2012-06-01

    The world's dominant IC material, silicon, cannot do everything we want a semiconductor material to do. However, for this discussion, the fact that Si wafers are of high quality, large and cheap is of great interest. This is important for at least two reasons. First, nearly all of the electronic and photonic compound semiconductor devices that comprise the current $20 billion per year market are fabricated on substrates that are either very expensive or non-optimal for the epitaxy required to realize the device or an IC of interest. A second reason is the integration of new functionality to current Si technology. Clearly, if many of the current photonic applications already realized in current compound semiconductor technology could be integrated into Si technology, some of the herculean efforts to continue following Moore's Law (including trying to do it via nanotechnology) could be mitigated. This presentation examines some of the basic materials science issues involved with heterogeneous integration of semiconductor materials. These include those applications in which the active device region requires a high degree of crystal perfection and those that do not. Epitaxy issues at the hetero-interface, heterovalent versus homovalent epigrowth, and dislocation dynamics are presented. Notable historical examples are summarized, followed by examples of current successful approaches including the materials science concepts used to achieve the results. A list is made of some challenges that need to be solved in order to continue making future progress.

  15. Year 1 Progress Report Computational Materials and Chemical Sciences Network Administration

    Energy Technology Data Exchange (ETDEWEB)

    Rehr, John J.

    2012-08-02

    This document reports progress on the project “Computational Materials and Chemical Sciences Network Administration,” which is supported by DOE BES Grant DE-FG02-02ER45990 MOD 08. As stated in the original proposal, the primary goal of this project is to carry out the scientific administrative responsibilities for the Computational Materials and Chemical Sciences Network (CMCSN) of the U.S. Department of Energy, Office of Basic Energy Sciences. These responsibilities include organizing meetings, publishing and maintaining CMCSN’s website, publishing a periodic newsletter, writing original material for both the website and the newsletter, maintaining CMCSN documentation, editing scientific documents, as needed, serving as liaison for the entire Network, facilitating information exchange across the network, communicating CMCSN’s success stories to the larger community and numerous other tasks outside the purview of the scientists in the CMCSN. Given the dramatic increase in computational power, advances in computational materials science can have an enormous impact in science and technology. For many of the questions that can be addressed by computation there is a choice of theoretical techniques available, yet often there is no accepted understanding of the relative strengths and effectiveness of the competing approaches. The CMCSN fosters progress in this understanding by providing modest additional funding to research groups which engage in collaborative activities to develop, compare, and test novel computational techniques. Thus, the CMCSN provides the “glue” money which enables different groups to work together, building on their existing programs and expertise while avoiding unnecessary duplication of effort. This includes travel funding, partial postdoc salaries, and funding for periodic scientific meetings. The activities supported by this grant are briefly summarized below.

  16. Current progress and future challenges in thermoelectric power generation: From materials to devices

    International Nuclear Information System (INIS)

    Thermoelectric power generation (TEG) represents one of the cleanest methods of energy conversion available today. It can be used in applications ranging from the harvesting of waste heat to conversion of solar energy into useful electricity. Remarkable advances have been achieved in recent years for various thermoelectric (TE) material systems. The introduction of nanostructures is used to tune the transport of phonons, while band structure engineering allows for the tailoring of electron transport. In this overview, top-down approaches to phonon engineering, such as atomic construction of new materials, will be reviewed. Bottom-up approaches to electron engineering, such as the formation of ordered nanostructures, will also be discussed. The assembly of TEG devices is still particularly challenging, and consequently, thermal-to-electric conversion utilizing these devices has been realized only in niche applications. In this review paper, we will discuss some of the challenges that must be overcome to enable widespread use of TE devices. These include thermal stability at the material level, and reliable contact at the device level

  17. Synthesis and design of silicide intermetallic materials. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.; Castro, R.G.; Butt, D.P.; Park, Y.; Vaidya, R.U.; Hollis, K.J.; Kung, H.H.

    1999-03-01

    The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the US processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive US processing industries. The program presently has a number of developing industrial connections, including a CRADA with Johns Manville Corporation targeted at the area of MoSi{sub 2}-based high temperature materials and components for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. With Combustion Technology Inc., they are developing silicide-based periscope sight tubes for the direct observation of glass melts. With Accutru International Corporation, they are developing silicide-based protective sheaths for self-verifying temperature sensors which may be used in glass furnaces and other industrial applications. The progress made on the program in this period is summarized.

  18. Progress in materials research and applications of high-Tc Superconductors

    International Nuclear Information System (INIS)

    Research on high-Tc superconductivity covers most of the fields of materials science, and therefore, interdisciplinary investigations are necessary by scientists with diverse backgrounds in physics, chemistry, ceramics, metallurgy and so on. At present, after much research on the physical properties of materials, the creation of a theory of high-Tc superconductivity is extremely urgent. If a theory can be successfully established, its effects must be very wide and deep. solid state physics may be transformed, and the search for new superconducting materials will be accelerated. Furthermore, many applications will be greatly advanced by understanding the phenomena of high-Tc materials, and especially concepts for new electronic devices may be forthcoming. In the past, interactions between science and technology have been very clear. They sometimes resonate with each other and exhibit rapid progress in a very short period and give a big impact on society. The research and developments of high-Tc superconductivity will hopefully retrace the brilliant history of the great success of the science and technology of semiconductors in the near future. The author is very optimistic about this

  19. Band structure of semiconductors

    CERN Document Server

    Tsidilkovski, I M

    2013-01-01

    Band Structure of Semiconductors provides a review of the theoretical and experimental methods of investigating band structure and an analysis of the results of the developments in this field. The book presents the problems, methods, and applications in the study of band structure. Topics on the computational methods of band structure; band structures of important semiconducting materials; behavior of an electron in a perturbed periodic field; effective masses and g-factors for the most commonly encountered band structures; and the treatment of cyclotron resonance, Shubnikov-de Haas oscillatio

  20. A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Prelas, M.A.

    1996-01-24

    This report describes progress made to develop a high bandgap photovoltaic materials for direct conversion to electricity of excimer radiation produced by fission energy pumped laser. This report summarizes the major achievements in sections. The first section covers n-type diamond. The second section covers forced diffusion. The third section covers radiation effects. The fourth section covers progress in Schottky barrier and heterojunction photovoltaic cells. The fifth section covers cell and reactor development.

  1. Nuclear measurements and reference materials annual progress report, january - december 1988

    International Nuclear Information System (INIS)

    The 1988 progress report of the Central Bureau for Nuclear Measurements (CBNM) is presented. The major changes in the role and orientation of the Joint Research Center, of which CBNM is an institute, are included. The main tasks of CBNM, which involve the program on Nuclear Measurements and Reference Materials, are given. Technical activities concerning the GELINA electron beam and Van de Graaff accelerators are reported. The study of transition radiation at linear electron accelerators, and the development of isotope dilution mass spectrometry, for trace analysis and isotope abundance measurements in iron and gallium, are summarized. The scientific and technical support to the commission, work for third parties, and contribution to conferences are presented

  2. Review of an assortment of IR materials-devices technologies used for imaging in spectral bands ranging from the visible to very long wavelengths

    Science.gov (United States)

    DeWames, Roger E.

    2016-05-01

    In this paper we review the intrinsic and extrinsic technological properties of the incumbent technology, InP/In0.53Ga0.47As/InP, for imaging in the visible- short wavelength spectral band, InSb and HgCdTe for imaging in the mid-wavelength spectral band and HgCdTe for imaging in the long wavelength spectral band. These material systems are in use for a wide range of applications addressing compelling needs in night vision imaging, low light level astronomical applications and defense strategic satellite sensing. These materials systems are direct band gap energy semiconductors hence the internal quantum efficiency η, is near unity over a wide spectral band pass. A key system figure of merit of a shot noise limited detector technology is given by the equation (1+Jdark. /Jphoton), where Jdark is the dark current density and Jphoton ~qηΦ is the photocurrent density; Φ is the photon flux incident on the detector and q is the electronic charge. The capability to maintain this factor for a specific spectral band close to unity for low illumination conditions and low temperature onset of non-ideal dark current components, basically intrinsic diffusion limited performance all the way, is a marker of quality and versatility of a semiconductor detector technology. It also enables the highest temperature of operation for tactical illumination conditions. A purpose of the work reported in this paper is to explore the focal plane array data sets of photodiode detector technologies widely used to bench mark their fundamental and technology properties and identify paths for improvements.

  3. Progress in the activities on prevention and combating of illicit trafficking of nuclear material in Lithuania

    International Nuclear Information System (INIS)

    Full text: The paper gives a general overview of the progress which has been made in the activities on prevention and combating of illicit trafficking of nuclear material in Lithuania. It describes the measures which were taken to strengthen nuclear material accounting and control and physical protection. The current status of the national legislation and the functions of institutions involved in control of nuclear material and combating of illicit trafficking are discussed. Lithuania, similar to many countries, did not avoid a new type of a crime - smuggling of nuclear materials - which was observed in the 1990's. The most serious case in Lithuania happened in 1993 when fresh fuel assembly was stolen from Ignalina NPP. This assembly contains approximately 124 kg of UO2 (enrichment 2%). 100 kg of the pellets from this assembly was found later in several pieces at different places. This case served as a strong stimulus to strengthen prevention measures of Illicit trafficking. The legal basis was created and governmental institutions were obliged with special duties related with nuclear material. The laws and regulations set the order for the shipment and handling of nuclear material. The penalties for violation of these laws and regulations specified in Penal Code and Administrative Code were made stricter. The State system of accounting for and control of nuclear material (SSAC) is a very important element in prevention of the illicit trafficking. The Regulations of Accounting for and Control of Nuclear Material at Nuclear Facilities and LOFs was issued by the State Nuclear Power Safety Inspectorate (VATESI) on 10 December 1997 following the provisions of the Law on Nuclear Energy. Lithuania extended its international obligations by ratifying the Protocol Additional to the Safeguards Agreement (entered into force on 5 July 2000). The fully computerized nuclear material accountancy system was created at Ignalina NPP. The system gives the possibility to find the

  4. Recent progress in MBE grown HgCdTe materials and devices at UWA

    Science.gov (United States)

    Gu, R.; Lei, W.; Antoszewski, J.; Madni, I.; Umana-Menbreno, G.; Faraone, L.

    2016-05-01

    HgCdTe has dominated the high performance end of the IR detector market for decades. At present, the fabrication costs of HgCdTe based advanced infrared devices is relatively high, due to the low yield associated with lattice matched CdZnTe substrates and a complicated cooling system. One approach to ease this problem is to use a cost effective alternative substrate, such as Si or GaAs. Recently, GaSb has emerged as a new alternative with better lattice matching. In addition, implementation of MBE-grown unipolar n-type/barrier/n-type detector structures in the HgCdTe material system has been recently proposed and studied intensively to enhance the detector operating temperature. The unipolar nBn photodetector structure can be used to substantially reduce dark current and noise without impeding photocurrent flow. In this paper, recent progress in MBE growth of HgCdTe infrared material at the University of Western Australia (UWA) is reported, including MBE growth of HgCdTe on GaSb alternative substrates and growth of HgCdTe nBn structures.

  5. Propulsion System Materials Program semiannual progress report for April 1995 through September 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    Significant accomplishments in fabricating ceramic components for the DOE, NASA, and DOD advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a 5-year program plan was developed with extensive input from private industry. During the course of the Propulsion System Materials Program, remarkable progress has been made in the development of reliable structural ceramics. However, further work is needed to reduce the cost of ceramics to facilitate their commercial introduction, especially in the highly cost-sensitive automotive market. To this end, the direction of the Propulsion System Materials Program is now shifting toward reducing the cost of ceramics to facilitate commercial introduction of ceramic components for near-term engine applications. In response to extensive input from industry, the plan is to extend the engine types which were previously supported to include near-term (5--10 years) applications in conventional automobile and diesel truck engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. A systematic approach to reducing the cost of components is envisioned. The work elements are as follows: economic cost modeling, ceramic machining, powder synthesis, alternative forming and densification processes, yield improvement, system design studies, standards development, low-expansion ceramics, and testing and data base development.

  6. Research progress of perovskite materials in photocatalysis- and photovoltaics-related energy conversion and environmental treatment.

    Science.gov (United States)

    Wang, Wei; Tadé, Moses O; Shao, Zongping

    2015-08-01

    Meeting the growing global energy demand is one of the important challenges of the 21st century. Currently over 80% of the world's energy requirements are supplied by the combustion of fossil fuels, which promotes global warming and has deleterious effects on our environment. Moreover, fossil fuels are non-renewable energy and will eventually be exhausted due to the high consumption rate. A new type of alternative energy that is clean, renewable and inexpensive is urgently needed. Several candidates are currently available such as hydraulic power, wind force and nuclear power. Solar energy is particularly attractive because it is essentially clean and inexhaustible. A year's worth of sunlight would provide more than 100 times the energy of the world's entire known fossil fuel reserves. Photocatalysis and photovoltaics are two of the most important routes for the utilization of solar energy. However, environmental protection is also critical to realize a sustainable future, and water pollution is a serious problem of current society. Photocatalysis is also an essential route for the degradation of organic dyes in wastewater. A type of compound with the defined structure of perovskite (ABX3) was observed to play important roles in photocatalysis and photovoltaics. These materials can be used as photocatalysts for water splitting reaction for hydrogen production and photo-degradation of organic dyes in wastewater as well as for photoanodes in dye-sensitized solar cells and light absorbers in perovskite-based solar cells for electricity generation. In this review paper, the recent progress of perovskites for applications in these fields is comprehensively summarized. A description of the basic principles of the water splitting reaction, photo-degradation of organic dyes and solar cells as well as the requirements for efficient photocatalysts is first provided. Then, emphasis is placed on the designation and strategies for perovskite catalysts to improve their

  7. Research progress of perovskite materials in photocatalysis- and photovoltaics-related energy conversion and environmental treatment.

    Science.gov (United States)

    Wang, Wei; Tadé, Moses O; Shao, Zongping

    2015-08-01

    Meeting the growing global energy demand is one of the important challenges of the 21st century. Currently over 80% of the world's energy requirements are supplied by the combustion of fossil fuels, which promotes global warming and has deleterious effects on our environment. Moreover, fossil fuels are non-renewable energy and will eventually be exhausted due to the high consumption rate. A new type of alternative energy that is clean, renewable and inexpensive is urgently needed. Several candidates are currently available such as hydraulic power, wind force and nuclear power. Solar energy is particularly attractive because it is essentially clean and inexhaustible. A year's worth of sunlight would provide more than 100 times the energy of the world's entire known fossil fuel reserves. Photocatalysis and photovoltaics are two of the most important routes for the utilization of solar energy. However, environmental protection is also critical to realize a sustainable future, and water pollution is a serious problem of current society. Photocatalysis is also an essential route for the degradation of organic dyes in wastewater. A type of compound with the defined structure of perovskite (ABX3) was observed to play important roles in photocatalysis and photovoltaics. These materials can be used as photocatalysts for water splitting reaction for hydrogen production and photo-degradation of organic dyes in wastewater as well as for photoanodes in dye-sensitized solar cells and light absorbers in perovskite-based solar cells for electricity generation. In this review paper, the recent progress of perovskites for applications in these fields is comprehensively summarized. A description of the basic principles of the water splitting reaction, photo-degradation of organic dyes and solar cells as well as the requirements for efficient photocatalysts is first provided. Then, emphasis is placed on the designation and strategies for perovskite catalysts to improve their

  8. The DIII-D Boundary/Plasma Materials Interaction Center (BPMIC): Progress and Prospects

    Science.gov (United States)

    Thomas, D.

    2015-11-01

    The boundary of a putative fusion reactor remains a key unresolved issue in the development of useful fusion energy. The BPMIC was established to develop validated boundary/PMI solutions for burning plasma devices by leveraging the existing DIII-D resources in well controlled, variable geometry edge plasmas and extensive boundary diagnostic set. During the first part of the 2015 campaign we have made significant progress in experiments designed to isolate specific known boundary and PMI physics issues and provide data for challenging existing analytical modeling tools such as the SOLPS suite and UEDGE. Topics include characterizing the relation between upstream and divertor parameters, the separate effects of closure and local magnetic geometry on detachment performance, leading edge tungsten erosion studies, and scaling relationships for the divertor heat flux width. This poster summarizes results from these experiments and will describe our high-level goals for the remainder of the 2015 campaign as well as for the 2016 campaign where we plan a campaign to study high-Z material migration and integration. Work supported by the US Department of Energy under DE-FC02-04ER54698.

  9. Analyzing Students' Learning Progressions throughout a Teaching Sequence on Acoustic Properties of Materials with a Model-Based Inquiry Approach

    Science.gov (United States)

    Hernández, María Isabel; Couso, Digna; Pintó, Roser

    2015-01-01

    The study we have carried out aims to characterize 15-to 16-year-old students' learning progressions throughout the implementation of a teaching-learning sequence on the acoustic properties of materials. Our purpose is to better understand students' modeling processes about this topic and to identify how the instructional design and actual…

  10. Spectrally resolved white light interferometry to measure material dispersion over a wide spectral band in a single acquisition.

    Science.gov (United States)

    Arosa, Yago; Lago, Elena López; Varela, Luis Miguel; de la Fuente, Raúl

    2016-07-25

    In this paper we apply spectrally resolved white light interferometry to measure refractive and group index over a wide spectral band from 400 to 1000 nm. The output of a Michelson interferometer is spectrally decomposed by a homemade prism spectrometer with a high resolution camera. The group index is determined directly from the phase extracted from the spectral interferogram while the refractive index is estimated once its value at a given wavelength is known. PMID:27464179

  11. Advanced Researech and Technology Development fossil energy materials program: Semiannual progress report for the period ending September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The objective of the ARandTD Fossil Energy Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. The ORNL Fossil Energy Materials Program Office compiles and issues this combined semiannual progress report from camera-ready copies submitted by each of the participating subcontractor organizations. This report of activities on the program is organized in accordance with a work breakdown structure in which projects are organized according to materials research thrust areas. These areas are (1) Structural Ceramics, (2) Alloy Development and Mechanical Properties, (3) Corrosion and Erosion of Alloys, and (4) Assessments and Technology Transfer. Individual projects are processed separately for the data bases.

  12. Geothermal elastomeric materials. Twelve-months progress report, October 1, 1976--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Hirasuna, A.R.; Bilyeu, G.D.; Davis, D.L.; Stephens, C.A.; Veal, G.R.

    1977-12-01

    Progress is reported on efforts to develop elastomers for packer seal element applications which will survive downhole geothermal well chemistry at 260/sup 0/C (500/sup 0/F) for 24 hours. To achieve this development, a three level elastomer testing and evaluation program was established. The first level Screening Tests is a broad screening of potential candidates and with the end objective to filter out the more promising candidates for more expensive subsequent testing. The battery of tests include standard ASTM tests and a special test developed to test extrusion resistance using specimens all made from sheet stock. The second level or Simulation Tests provide a laboratory equivalent of downhole conditions using synthetic geothermal fluid. Full scale packer seals are tested under simulated operational conditions by a test fixture. The third level or In-Situ Tests which are currently in the planning, provide for testing the most favored materials in-situ in the geothermal well. A test module provides for testing of the specimen without interfacing with the well casing. A test module freely hanging on a wireline has much lower probability of causing a problem, such as becoming lodged in the well, as compared to an operational casing packer. This maximizes the number of wells (hence geothermal environments) where access can be gained and In-Situ Testing performed. During this period commercially available polymers were investigated. Most of the work centered around formulating peroxide cured Vitons and some on EPDMs, butyls, and resin cured Vitons. Of the formulations tested to date the EPDMs appear most promising and the peroxide cured Vitons next most promising. However, data is too sparse to make any firm conclusions at this time. Minor tasks were performed evaluating current commercially available elastomers used in oil tools and conceptualization of casing packer for the geothermal application.

  13. Advanced research and technology development fossil energy materials program. Quarterly progress report for the period ending September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, R.A. (comp.)

    1981-12-01

    This is the fourth combined quarterly progress report for those projects that are part of the Advanced Research and Technology Development Fossil Energy Materials Program. The objective is to conduct a program of research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Work performed on the program generally falls into the Applied Research and Exploratory Development categories as defined in the DOE Technology Base Review, although basic research and engineering development are also conducted. A substantial portion of the work on the AR and TD Fossil Energy Materials Program is performed by participating cntractor organizations. All subcontractor work is monitored by Program staff members at ORNL and Argonne National Laboratory. This report is organized in accordance with a work breakdown structure defined in the AR and TD Fossil Energy Materials Program Plan for FY 1981 in which projects are organized according to fossil energy technologies. We hope this series of AR and TD Fossil Energy Materials Program quarterly progress reports will aid in the dissemination of information developed on the program.

  14. High-Temperature Materials Program quarterly progress report for period ending January 31, 1965

    Energy Technology Data Exchange (ETDEWEB)

    Thurber, W.C. (comp.)

    1965-03-01

    This report is divided into five sections: high-temperature materials development, materials compatibility studies, behavior of high-temperature materials under irradiation, uranium nitride, and tungsten metallurgy. (DLC)

  15. Study of non aqueous reprocessing methods. Final progress report. [Container materials for pyrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Teitel, R. J.; Luderer, J. E.; Henderson, T. M.

    1978-11-17

    The problems associated with container materials for selected pyrochemical processes and process containment conditions are reviewed. A rationale for container materials selection is developed. Candidate process container materials are presented, and areas warranting further development are identified. 14 tables.

  16. Fourth annual progress report on special-purpose materials for magnetically confined fusion reactors

    International Nuclear Information System (INIS)

    The scope of Special Purpose Materials covers fusion reactor materials problems other than the first-wall and blanket structural materials, which are under the purview of the ADIP, DAFS, and PMI task groups. Components that are considered as special purpose materials include breeding materials, coolants, neutron multipliers, barriers for tritium control, materials for compression and OH coils and waveguides, graphite and SiC, heat-sink materials, ceramics, and materials for high-field (>10-T) superconducting magnets. The Task Group on Special Purpose Materials has limited its concern to crucial and generic materials problems that must be resolved if magnetic-fusion devices are to succeed. Important areas specifically excluded include low-field (8-T) superconductors, fuels for hybrids, and materials for inertial-confinement devices. These areas may be added in the future when funding permits

  17. Electronic structure of layered quaternary chalcogenide materials for band-gap engineering: The example of Cs2MIIM3IVQ8

    Science.gov (United States)

    Besse, Rafael; Sabino, Fernando P.; Da Silva, Juarez L. F.

    2016-04-01

    Quaternary chalcogenide materials offer a wide variety of chemical and physical properties, and hence, those compounds have been widely studied for several technological applications. Recently, experimental studies have found that the chalcogenide Cs2MIIM3IVQ8 family (MII = Mg , Zn , Cd , Hg , MIV = Ge , Sn and Q = S , Se , Te ), which includes 24 compounds, yields a wide range of band gaps, namely, from 1.07 to 3.4 eV, and hence, they have attracted great interest. To obtain an improved atomistic understanding of the role of the cations and anions on the physical properties, we performed a first-principles investigation of the 24 Cs2MIIM3IVQ8 compounds employing density functional theory within semilocal and hybrid exchange-correlation energy functionals and the addition of van der Waals corrections to improve the description of the weakly interacting layers. Our lattice parameters are in good agreement with the available experimental data (i.e., 11 compounds), and the equilibrium volume increases linearly by increasing the atomic number of the chalcogen, which can be explained by the increased atomic radius of the chalcogen atoms from S to Te . We found that van der Waals corrections play a crucial role in the lattice parameter in the stacking direction of the Cs2MIIM3IVQ8 layers, while the binding energy per unit area has similar magnitude as obtained for different layered materials. We obtained that the band gaps follow a linear relation as a function of the unit cell volume, which can be explained by the atomic size of the chalcogen atom and the relative position of the Q p states within the band structure. The fundamental and optical band gaps differ by less than 0.1 eV. The band gaps obtained with the hybrid functional are in good agreement with the available experimental data. Furthermore, we found from the Bader analysis, that the Coulomb interations among the cations and anions play a crucial role on the energetic properties.

  18. AR and TD Fossil Energy Materials Program. Quarterly progress report for the period ending December 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1982-04-01

    The ORNL Fossil Energy Materials Program Office compiles and issues this combined quarterly progress report from camera-ready copies submitted by each of the participating subcontractor organizations. This report of activities on the program is organized in accordance with a work breakdown structure defined in the AR and TD Fossil Energy Materials Program Plan for FY 1982-1986 in which projects are organized according to fossil energy technologies. This report is divided into parts and chapters with each part describing projects related to a particular fossil energy technology. Chapters within a part provide details of the various projects associated with that technology. We hope this series of AR and TD Fossil Energy Materials Program quarterly progress reports will aid in the dissemination of information developed on the program. Plans for the program will be issued annually. A draft of the program plan for FY 1982 to 1986 has been prepared and is in the review process. The implementation of these plans will be reflected by these quarterly progress reports, and this dissemination of information will bw augmented by topical or final reports as appropriate.

  19. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    KAUST Repository

    Qin, Peng

    2014-07-15

    Novel low band gap oligothiophenes incorporating S,N-heteropentacene central units were developed and used as hole-transport materials (HTMs) in solid-state perovskite-based solar cells. In addition to appropriate electronic energy levels, these materials show high photo-absorptivity in the low energy region, and thus can contribute to the light harvesting of the solar spectrum. Solution-processed CH3NH3PbI3-based devices using these HTMs achieved power conversion efficiencies of 9.5-10.5% in comparison with 7.6% obtained by reference devices without HTMs. Photoinduced absorption spectroscopy gave further insight into the charge transfer behavior between photoexcited perovskites and the HTMs. This journal is © the Partner Organisations 2014.

  20. Special-purpose materials for magnetically confined fusion reactors. Third annual progress report

    International Nuclear Information System (INIS)

    The scope of Special Purpose Materials covers fusion reactor materials problems other than the first-wall and blanket structural materials, which are under the purview of the ADIP, DAFS, and PMI task groups. Components that are considered as special purpose materials include breeding materials, coolants, neutron multipliers, barriers for tritium control, materials for compression and OH coils and waveguides, graphite and SiC, heat-sink materials, ceramics, and materials for high-field (>10-T) superconducting magnets. It is recognized that there will be numerous materials problems that will arise during the design and construction of large magnetic-fusion energy devices such as the Engineering Test Facility (ETF) and Demonstration Reactor (DEMO). Most of these problems will be specific to a particular design or project and are the responsibility of the project, not the Materials and Radiation Effects Branch. Consequently, the Task Group on Special Purpose Materials has limited its concern to crucial and generic materials problems that must be resolved if magnetic-fusion devices are to succeed. Important areas specifically excluded include low-field (8-T) superconductors, fuels for hybrids, and materials for inertial-confinement devices. These areas may be added in the future when funding permits

  1. The Voigt effects in the anisotropic photonic band gaps of three-dimensional magnetized plasma photonic crystals doped by the uniaxial material

    Science.gov (United States)

    Zhang, Hai-Feng; Liu, Shao-Bin; Li, Bing-Xiang

    2013-10-01

    In this paper, the properties of photonic band gaps (PBGs) for three-dimensional magnetized plasma photonic crystals (MPPCs) composed of anisotropic dielectric (the uniaxial material) spheres immersed in homogeneous magnetized plasma background with simple-cubic lattices are theoretically investigated by the plane wave expansion (PWE) method, as the Voigt effects of magnetized plasma are considered. The equations for calculating the anisotropic PBGs in the first irreducible Brillouin zone are theoretically deduced. The anisotropic PBGs and two flatband regions can be obtained. The effects of the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency and plasma cyclotron frequency on the characteristics of anisotropic PBGs for the three-dimensional MPPCs are studied in detail and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in simple-cubic lattices and the complete PBGs can be found compared to the conventional three-dimensional MPPCs doped by the isotropic material. The bandwidths of PBGs can be enlarged by introducing the magnetized plasma into three-dimensional PCs containing the uniaxial material. It is also shown that the anisotropic PBGs can be manipulated by the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency and plasma cyclotron frequency. The locations of flatband regions cannot be tuned by any parameters except for the plasma frequency and plasma cyclotron frequency. Introducing the uniaxial material in three-dimensional magnetized plasma-dielectric photonic crystals can enlarge the PBGs and also provide a way to obtain the complete PBGs as the three-dimensional MPPCs with high symmetry.

  2. Technical Progress Report for "Optical and Electrical Properties of III-Nitrides and Related Materials"

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hongxing

    2008-10-31

    Investigations have been conducted focused on the fundamental material properties of AIN and high AI-content AIGaN alloys and further developed MOCVD growth technologies for obtaining these materials with improved crystalline quality and conductivities.

  3. Progress report, Chemistry and Materials Division, October 1 to December 31, 1976

    International Nuclear Information System (INIS)

    A summary is given of research largely centering around radiation effects on materials, radiation and analytical chemistry, surface studies, and materials science, esp. zirconium base alloys and their problems and properties in nuclear service. (E.C.B.)

  4. Human Immunodeficiency Virus (HIV types Western blot (WB band profiles as potential surrogate markers of HIV disease progression and predictors of vertical transmission in a cohort of infected but antiretroviral therapy naïve pregnant women in Harare, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Chirenje Mike Z

    2011-01-01

    Full Text Available Abstract Background Expensive CD4 count and viral load tests have failed the intended objective of enabling access to HIV therapy in poor resource settings. It is imperative to develop simple, affordable and non-subjective disease monitoring tools to complement clinical staging efforts of inexperienced health personnel currently manning most healthcare centres because of brain drain. Besides accurately predicting HIV infection, sequential appearance of specific bands of WB test offers a window of opportunity to develop a less subjective tool for monitoring disease progression. Methods HIV type characterization was done in a cohort of infected pregnant women at 36 gestational weeks using WB test. Student-t test was used to determine maternal differences in mean full blood counts and viral load of mothers with and those without HIV gag antigen bands. Pearson Chi-square test was used to assess differences in lack of bands appearance with vertical transmission and lymphadenopathy. Results Among the 64 HIV infected pregnant women, 98.4% had pure HIV-1 infection and one woman (1.7% had dual HIV-1/HIV-2 infections. Absence of HIV pol antigen bands was associated with acute infection, p = 0.002. All women with chronic HIV-1 infection had antibody reactivity to both the HIV-1 envelope and polymerase antigens. However, antibody reactivity to gag antigens varied among the women, being 100%, 90%, 70% and 63% for p24, p17, p39 and p55, respectively. Lack of antibody reactivity to gag p39 antigen was associated with disease progression as confirmed by the presence of lymphadenopathy, anemia, higher viral load, p = 0.010, 0.025 and 0.016, respectively. Although not statistically significant, women with p39 band missing were 1.4 times more likely to transmit HIV-1 to their infants. Conclusion Absence of antibody reactivity to pol and gag p39 antigens was associated with acute infection and disease progression, respectively. Apart from its use in HIV disease

  5. University of Illinois at Urbana-Champaign, Materials Research Laboratory progress report for FY 1991

    International Nuclear Information System (INIS)

    The Materials Research Laboratory at the University of Illinois is an interdisciplinary laboratory operated in the College of Engineering. Its focus is the science of materials and it supports research in the areas of condensed matter physics, solid state chemistry, and materials science. This report addresses topics such as: an MRL overview; budget; general programmatic and institutional issues; new programs; research summaries for metallurgy, ceramics, solid state physics, and materials chemistry

  6. University of Illinois at Urbana-Champaign, Materials Research Laboratory progress report for FY 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    The Materials Research Laboratory at the University of Illinois is an interdisciplinary laboratory operated in the College of Engineering. Its focus is the science of materials and it supports research in the areas of condensed matter physics, solid state chemistry, and materials science. This report addresses topics such as: an MRL overview; budget; general programmatic and institutional issues; new programs; research summaries for metallurgy, ceramics, solid state physics, and materials chemistry.

  7. Fusion Reactor Materials semiannual progress report for period ending September 30, 1991

    International Nuclear Information System (INIS)

    This report contains papers on topic in the following areas of thermonuclear reactor materials: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials and beryllium; and ceramics. These paper have been index separately elsewhere. (LSP)

  8. Fusion reactor materials: Semiannual progress report for the period ending March 31, 1988

    International Nuclear Information System (INIS)

    This report contains papers on thermonuclear reactor materials. The general categories of these papers are: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; development of structural alloys; solid breeding materials; ceramics; and radiation effects. Selected papers have been processed for inclusion in the energy database

  9. Fusion reactor materials semiannual progress report for the period ending September 30, 1988

    International Nuclear Information System (INIS)

    This paper discusses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics

  10. Fusion Reactor Materials semiannual progress report for period ending September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1992-04-01

    This report contains papers on topic in the following areas of thermonuclear reactor materials: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials and beryllium; and ceramics. These paper have been index separately elsewhere. (LSP).

  11. Fusion reactor materials semiannual progress report for the period ending September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1989-04-01

    This paper discusses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

  12. Fusion reactor materials: Semiannual progress report for the period ending March 31, 1988

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1988-08-01

    This report contains papers on thermonuclear reactor materials. The general categories of these papers are: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; development of structural alloys; solid breeding materials; ceramics; and radiation effects. Selected papers have been processed for inclusion in the energy database. (LSP)

  13. DUAL-BAND INFRARED DETECTORS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As the infrared technology continues to advance, there is a growing demand for multispectral detectors for advanced IR systems with better target discrimination and identification. Both HgCdTe detectors and quantum well GaAs/AlGaAs photodetectors offer wavelength flexibility from medium wavelength to very long wavelength and multicolor capability in these regions. The main challenges facing all multicolor devices are more complicated device structtures, thicker and multilayer material growth, and more difficult device fabrication, especially when the array size gets larger and pixel size gets smaller. In the paper recent progress in development of two-color HgCdTe photodiodes and quantum well infrared photodetectors is presented.More attention is devoted to HgCdTe detectors. The two-color detector arrays are based upon an n-P-N (the capital letters mean the materials with larger bandgap energy) HgCdTe triple layer heterojunction design. Vertically stacking the two p-n junctions permits incorporation of both detectros into a single pixel. Both sequential mode and simultaneous mode detectors are fabricated. The mode of detection is determined by the fabrication process of the multilayer materials.Also the performances of stacked multicolor QWIPs detectors are presented. For multicolor arrays, QWIP's narrow band spectrum is an advantage, resulting in low spectral crosstalk. The major challenge for QWIP is developing broadband or multicolor optical coupling structures that permit efficient absorption of all required spectral bands.

  14. Fusion reactor materials: Semiannual progress report for period ending September 30, 1986

    International Nuclear Information System (INIS)

    These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The major areas of concern covered in this report are irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; radiation effects; development of structural alloys; solid breeding materials; ceramics and superconducting magnet materials. There are 61 reports cataloged separately

  15. Fusion reactor materials: Semiannual progress report for period ending September 30, 1986

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1987-09-01

    These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials program being conducted in support of the Magnetic Fusion Energy Program of the US Department of Energy. The major areas of concern covered in this report are irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters and activation calculations; materials engineering and design requirements; radiation effects; development of structural alloys; solid breeding materials; ceramics and superconducting magnet materials. There are 61 reports cataloged separately. (LSP)

  16. Recent progress in R and D on tungsten alloys for divertor structural and plasma facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Wurster, S., E-mail: stefan.wurster@oeaw.ac.at [Erich Schmid Institute of Materials Science, Austria and Association EURATOM-ÖAW, Jahnstrasse 12, A-8700 Leoben (Austria); Baluc, N.; Battabyal, M. [Ecole Polytechnique Fédérale de Lausanne (EPFL), Villigen PSI (Switzerland); Crosby, T. [University of California, Mechanical and Aerospace Engineering Department, Los Angeles, CA (United States); Du, J. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); García-Rosales, C. [Centro de Estudios e Investigaciones Técnicas de Gipuzkoa (CEIT), San Sebastián (Spain); Hasegawa, A. [Department of Quantum Science and Energy Engineering, Faculty of Engineering, Tohoku University (Japan); Hoffmann, A. [Plansee Metall GmbH, Reutte (Austria); Kimura, A. [Institute of Advanced Energy, Kyoto University (Japan); Kurishita, H. [International Research Center for Nuclear Material Science, Institute for Materials Research, Tohoku University (Japan); Kurtz, R.J. [Pacific Northwest National Laboratory, Richland, WA (United States); Li, H. [Erich Schmid Institute of Materials Science, Austria and Association EURATOM-ÖAW, Jahnstrasse 12, A-8700 Leoben (Austria); Chair of Atomistic Modelling and Design of Materials, University of Leoben, Leoben (Austria); Noh, S.; Reiser, J. [Karlsruhe Institute of Technology, Karlsruhe (Germany); Riesch, J. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Rieth, M. [Karlsruhe Institute of Technology, Karlsruhe (Germany); Setyawan, W. [Pacific Northwest National Laboratory, Richland, WA (United States); Walter, M. [Karlsruhe Institute of Technology, Karlsruhe (Germany); You, J.-H. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); and others

    2013-11-15

    Tungsten materials are candidates for plasma-facing components for the International Thermonuclear Experimental Reactor and the DEMOnstration power plant because of their superior thermophysical properties. Because these materials are not common structural materials like steels, knowledge and strategies to improve the properties are still under development. These strategies discussed here, include new alloying approaches and microstructural stabilization by oxide dispersion strengthened as well as TiC stabilized tungsten based materials. The fracture behavior is improved by using tungsten laminated and tungsten wire reinforced materials. Material development is accompanied by neutron irradiation campaigns. Self-passivation, which is essential in case of loss-of-coolant accidents for plasma facing materials, can be achieved by certain amounts of chromium and titanium. Furthermore, modeling and computer simulation on the influence of alloying elements and heat loading and helium bombardment will be presented.

  17. The study of below and above band-edge imperfection states in In{sub 2}S{sub 3} solar energy materials

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hwa, E-mail: chho@mail.ntust.edu.tw [Graduate Institute of Engineering, Graduate Institute of Applied Science and Engineering, and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

    2012-08-01

    {beta}-In{sub 2}S{sub 3} is a nontoxic buffer layer material usually used in a thin-film solar cell due to a lot of vacancies and surface states naturally existing in the crystal to assist in photoelectric conversion. Transition metal (TM)-incorporated {beta}-In{sub 2}S{sub 3} has also been proposed to increase conversion efficiency in In{sub 2}S{sub 3} since multi-photons absorption by intermediate band (IB) would happen in the sulfide. In this paper, single crystals of undoped and Nb-doped {beta}-In{sub 2}S{sub 3} have been grown by the chemical vapor transport (CVT) method using ICl{sub 3} as a transport agent. Optical properties of the imperfection states of the crystals are probed by thermoreflectance (TR), photoconductivity (PC), photoluminescence (PL), surface photoconductive response (SPR), optical absorption and photo-voltage-current (photo V-I) measurements. The TR and optical-absorption measurements confirmed that the undoped and Nb-doped {beta}-In{sub 2}S{sub 3} are direct semiconductors with energy gap of 1.935 eV for undoped {beta}-In{sub 2}S{sub 3}, 1.923 eV for {beta}-In{sub 2}S{sub 3}:Nb{sub 0.005}, and 1.901 eV for {beta}-In{sub 2}S{sub 3}:Nb{sub 0.01}. For undoped {beta}-In{sub 2}S{sub 3}, PC and PL measurements are used to characterize defect transitions below band gap. The above band-edge transitions of undoped {beta}-In{sub 2}S{sub 3} have also been evaluated using PL, PC, and SPR measurements. For the evaluation of Nb-doped {beta}-In{sub 2}S{sub 3}, an intermediate band with energy of {approx}0.4 eV below the conduction band edge has been detected in the TR measurements in both {beta}-In{sub 2}S{sub 3}:Nb{sub 0.005} and {beta}-In{sub 2}S{sub 3}:Nb{sub 0.01}. The photo V-I measurements also verified that the photoelectric-conversion efficiency would be enhanced in the {beta}-In{sub 2}S{sub 3} with higher niobium content. Based on the experimental analyses, the optical behavior of the defects, surface states, and IB (formed by Nb) in the In

  18. Area dependence of femtosecond laser-induced periodic surface structures for varying band gap materials after double pulse excitation

    Energy Technology Data Exchange (ETDEWEB)

    Höhm, S., E-mail: Hoehm@mbi-berlin.de [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Rosenfeld, A. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Krüger, J.; Bonse, J. [BAM Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)

    2013-08-01

    The formation of laser-induced periodic surface structures upon irradiation of titanium, silicon, and fused silica with multiple irradiation sequences consisting of parallel polarized Ti:sapphire femtosecond laser pulse pairs (pulse duration 50–150 fs, central wavelength ∼800 nm) is studied experimentally. The temporal delay between the individual near-equal energy fs-laser pulses was varied between 0 and 5 ps with a temporal resolution of better than 0.2 ps. The surface morphology of the irradiated surface areas is characterized by means of scanning electron microscopy (SEM). In all materials a decrease of the rippled surface area is observed for increasing delays. The characteristic delay decay scale is quantified and related to material dependent excitation and energy relaxation processes.

  19. Progress Made in the Studies of Novel Materials for Organic Semiconductors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Co-funded by NSFC, Ministry of Science & Technology of China (MOST) and the Chinese Academy of Sciences (CAS), researchers at the Key Laboratory of Organic Solids, ICCAS, made progress in designing and synthesis of n- and p-type organic semiconductors.

  20. Fusion materials semiannual progress report for the period ending June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. It is divided into the following chapters: vanadium alloys; silicon carbide components; ferritic-martensitic steels; copper alloys and high heat flux materials; austenitic stainless steels; insulating ceramics and optical materials; radiation effects, mechanistic studies, and experimental methods; dosimetry, damage parameters, and activation calculations; and irradiation facilities, test matrices, and experimental methods. There were no papers for the chapters on solid breeding materials and materials engineering and design requirement. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  1. Fusion materials semiannual progress report for the period ending June 30, 1996

    International Nuclear Information System (INIS)

    This report combines the full spectrum of research and development activities on both metallic and non-metallic materials with primary emphasis on the effects of the neutronic and chemical environment on the properties and performance of materials for in-vessel components. It is divided into the following chapters: vanadium alloys; silicon carbide components; ferritic-martensitic steels; copper alloys and high heat flux materials; austenitic stainless steels; insulating ceramics and optical materials; radiation effects, mechanistic studies, and experimental methods; dosimetry, damage parameters, and activation calculations; and irradiation facilities, test matrices, and experimental methods. There were no papers for the chapters on solid breeding materials and materials engineering and design requirement. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  2. Progress on first-principles-based materials design for hydrogen storage

    OpenAIRE

    Park, Noejung; Choi, Keunsu; Hwang, Jeongwoon; Kim, Dong Wook; Kim, Dong Ok; Ihm, Jisoon

    2012-01-01

    This article briefly summarizes the research activities in the field of hydrogen storage in sorbent materials and reports our recent works and future directions for the design of such materials. Distinct features of sorption-based hydrogen storage methods are described compared with metal hydrides and complex chemical hydrides. We classify the studies of hydrogen sorbent materials in terms of two key technical issues: (i) constructing stable framework structures with high porosity, and (ii) i...

  3. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1978

    International Nuclear Information System (INIS)

    Topics covered include: structure of materials, theoretical research; x-ray diffraction research; fundamental ceramics studies; preparation and synthesis of high-temperature and special service materials; physical metallurgy; grain boundary segregation and fracture; mechanisms of surface and solid-state reactions; physical properties research; superconducting materials; radiation effects; facility and technique development; nuclear microanalysis; cooperative studies with universities and other research organizations; and fundamentals of welding and joining

  4. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.; Peterson, S. (comps.)

    1978-09-01

    Topics covered include: structure of materials, theoretical research; x-ray diffraction research; fundamental ceramics studies; preparation and synthesis of high-temperature and special service materials; physical metallurgy; grain boundary segregation and fracture; mechanisms of surface and solid-state reactions; physical properties research; superconducting materials; radiation effects; facility and technique development; nuclear microanalysis; cooperative studies with universities and other research organizations; and fundamentals of welding and joining. (GHT)

  5. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending June 30, 1984

    International Nuclear Information System (INIS)

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division for the period January 1, 1983, to June 30, 1984. These activities constitute about one-fourth of the research and development conducted by the division. The emphasis of the program can be described as the scientific design of materials. The efforts are directed toward three classes of materials: high-temperature metallic alloys based on intermetallic compounds, structural ceramics, and radiation-resistant alloys

  6. Chemistry {ampersand} Materials Science progress report summary of selected research and development topics, FY97

    Energy Technology Data Exchange (ETDEWEB)

    Newkirk, L.

    1997-12-01

    This report contains summaries of research performed in the Chemistry and Materials Science division. Topics include Metals and Ceramics, High Explosives, Organic Synthesis, Instrument Development, and other topics.

  7. 1996 Progress report on energies and raw materials; 1996 rapport d`activite energies et matieres premieres

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The 1996 annual progress report, from the French Department of Energy, reviews the key points of the French policy for energy and raw materials: competitiveness, environmental protection, long term supply safety, and public service. 1996 was marked by positive results for the French energy industry, difficulties for the oil refining industry, and a new impetus for renewable energies. Five surveys are presented: nuclear safety in Eastern Europe, the european directive on electric power domestic market, evolution of the oil market, conditions of refining in France, and restructuring of the Mine bureau (BRGM). 40 prominent facts are briefly reviewed, concerning sustainable energy development, nuclear energy, electric power and gas, coal, oil products, raw materials. Diagrams on energy and raw materials are also included

  8. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, January 1, 1980-March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-25

    Results are presented of work performed on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Included are the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described, including screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850, and 950/sup 0/C.

  9. Fusion reactor materials semiannual progress report for the period ending March 31, 1990

    Energy Technology Data Exchange (ETDEWEB)

    1990-08-01

    This report mainly discusses topics on the physical effects of radiation on thermonuclear reactor materials. The areas discussed are: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; fundamental mechanical behavior; radiation effects; mechanistic studies, theory and modeling; development of structural alloys; solid breeding materials; and ceramics. (FI)

  10. University of Illinois at Urbana-Champaign, Materials Research Laboratory progress report for FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    This interdisciplinary laboratory in the College of Engineering support research in areas of condensed matter physics, solid state chemistry, and materials science. These research programs are developed with the assistance of faculty, students, and research associates in the departments of Physics, Materials Science and Engineering, chemistry, Chemical Engineering, Electrical Engineering, Mechanical Engineering, and Nuclear Engineering.

  11. Fusion reactor materials semiannual progress report for period ending September 30, 1992

    International Nuclear Information System (INIS)

    This report contains papers on the following topics on thermonuclear reactor materials: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters,and activation calculations; radiation effects, mechanistic studies, theory and modeling; development of structural alloys; solid breeding materials and beryllium; and ceramics. These reports have been index separately elsewhere

  12. Recent Progress in Nanostructured Oxide TE Materials for Power Generation at High Temperatures

    DEFF Research Database (Denmark)

    Van Nong, Ngo; Pryds, Nini; Linderoth, Søren;

    Thermoelectric (TE) materials, which can convert waste heat into electricity, could play an important role in a global sustainable energy solution and environmental problems. Metal oxides have been considered as potential TE materials for power generation that can operate at high temperatures on ...

  13. High-temperature materials program. Progress report No. 34, Part B

    Energy Technology Data Exchange (ETDEWEB)

    1964-04-15

    Information is presented concerning coated fuel particle development and evaluation; burnup capabilities of Y/sub 2/O/sub 3/-stabilized UO/sub 2/ and stabilized fuel - BeO matrix materials; high-temperature studies of substoichiometric urania and urania solid solutions; high-temperature carbides and borides research; and high-flux reactor materials gaseous fuels research.

  14. Fusion reactor materials semiannual progress report for the period ending March 31, 1990

    International Nuclear Information System (INIS)

    This report mainly discusses topics on the physical effects of radiation on thermonuclear reactor materials. The areas discussed are: irradiation facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; fundamental mechanical behavior; radiation effects; mechanistic studies, theory and modeling; development of structural alloys; solid breeding materials; and ceramics. (FI)

  15. Helium generation in fusion-reactor materials. Progress report, January-March 1981

    International Nuclear Information System (INIS)

    The objectives of this program are to measure helium generation rates of materials for Magnetic Fusion Reactor applications in the various neutron environments used for fusion reactor materials testing, to characterize these neutron test environments, and to develop helium accumulation neutron dosimeters for neutron fluence and energy spectrum dosimetry in these test environments

  16. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending December 31, 1982

    International Nuclear Information System (INIS)

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division. These activities constitute about one-fourth of the research and development conducted by the division. The major elements of the Materials Sciences Program can be grouped under the areas of (1) structural characterization, (2) high-temperature alloy studies, (3) structural ceramics, and (4) radiation effects

  17. Science of materials. Progress report, January 1, 1981-December 31, 1981

    International Nuclear Information System (INIS)

    The research program is designed to provide information concerning basic properties of materials that are important for the development of energy systems. The emphasis is on the synthesis and characterization of new materials with novel properties for future applications. The research program includes studies of the microchemistry and microstructure; the deformation, corrosion and fracture of metals, ceramics and alloy materials are of particular concern, as is the hydrogen embrittlement of metals; also under investigation are the mechanism of heat transfer across interfaces, catalytic properties of surfaces, and erosion of surfaces by fluid suspended particles. The new materials and materials configurations now being fabricated for research on energy applications include a variety of metastable ceramic, metallic, semi-conducting and molecular assemblies

  18. Improved performance of dye sensitized solar cells using Cu-doped TiO2 as photoanode materials: Band edge movement study by spectroelectrochemistry

    Science.gov (United States)

    Zhou, Li; Wei, Liguo; Yang, Yulin; Xia, Xue; Wang, Ping; Yu, Jia; Luan, Tianzhu

    2016-08-01

    Cu-doped TiO2 nanoparticles are prepared and used as semiconductor materials of photoanode to improve the performance of dye sensitized solar cells (DSSCs). UV-Vis spectroscopy and variable temperature spectroelectrochemistry study are used to characterize the influence of copper dopant with different concentrations on the band gap energies of TiO2 nanoparticles. The prepared Cu-doped TiO2 semiconductor has avoided the formation of CuO during hydrothermal process and lowered the conduction band position of TiO2, which contribute to increase the short circuit current density of DSSCs. At the optimum Cu concentration of 1.0 at.%, the short circuit current density increased from 12.54 to 14.98 mA cm-2, full sun solar power conversion efficiencies increased from 5.58% up to 6.71% as compared to the blank DSSC. This showed that the presence of copper in DSSCs leads to improvements of up to 20% in the conversion efficiency of DSSCs.

  19. Heavy Vehicle Propulsion System Materials Program semiannual progress report for October 1996 through March 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks. The design of advanced components for high-efficiency diesel engines has, in some cases, pushed the performance envelope for materials of construction past the point of reliable operation. Higher mechanical and tribological stresses and higher temperatures of advanced designs limit the engine designers; advanced materials allow the design of components that may operate reliably at higher stresses and temperatures, thus enabling more efficient engine designs. Advanced materials also offer the opportunity to improve the emissions, NVH, and performance of diesel engines for pickup trucks, vans, and sport utility vehicles. The principal areas of research are: (1) cost effective high performance materials and processing; (2) advanced manufacturing technology; (3) testing and characterization; and (4) materials and testing standards.

  20. Recent research progress on iron- and manganese-based positive electrode materials for rechargeable sodium batteries

    International Nuclear Information System (INIS)

    Large-scale high-energy batteries with electrode materials made from the Earth-abundant elements are needed to achieve sustainable energy development. On the basis of material abundance, rechargeable sodium batteries with iron- and manganese-based positive electrode materials are the ideal candidates for large-scale batteries. In this review, iron- and manganese-based electrode materials, oxides, phosphates, fluorides, etc, as positive electrodes for rechargeable sodium batteries are reviewed. Iron and manganese compounds with sodium ions provide high structural flexibility. Two layered polymorphs, O3- and P2-type layered structures, show different electrode performance in Na cells related to the different phase transition and sodium migration processes on sodium extraction/insertion. Similar to layered oxides, iron/manganese phosphates and pyrophosphates also provide the different framework structures, which are used as sodium insertion host materials. Electrode performance and reaction mechanisms of the iron- and manganese-based electrode materials in Na cells are described and the similarities and differences with lithium counterparts are also discussed. Together with these results, the possibility of the high-energy battery system with electrode materials made from only Earth-abundant elements is reviewed. (review)

  1. Isotopic power materials development. Quarterly progress report for period ending March 31, 1976

    International Nuclear Information System (INIS)

    The second in a series of quarterly reports for Technology and Space Applications materials programs conducted by the Metals and Ceramics Division of Oak Ridge National Laboratory for the Nuclear Research and Applications Division of ERDA is presented. These quarterly reports replace the monthly and annual reports previously issued on this work. The areas of research covered include high-temperature alloys for space isotopic heat sources, physical and mechanical metallurgy of heat source containment materials, isotope Brayton system materials support, and space nuclear flight systems hardware

  2. Comprehensive investigation of optical and electronic properties of tunable InAs QDs optically active at O-band telecommunication window with (In)GaAs surrounding material

    International Nuclear Information System (INIS)

    In this paper, we report on the impact of InAs quantum dots' (QDs) position within InGaAs strain reducing layer on their structural and optical properties. Morphological investigation revealed that the QD' size and density are strongly dependent on the InGaAs underlying layer's thickness. Additionally, comprehensive spectroscopic study by room temperature photoreflectance spectroscopy (PR) and temperature dependent photoluminescence (PL) showed that indium segregation and strain driven alloy phase separation alter both the QDs and their surrounding materials. Embedding or covering the InAs QDs by InGaAs has been found to improve their overall properties including an extended emission wavelength up to 1.3 μm. However a pronounced degradation has been observed when growing them on the top of the strain reducing layer, resulting in a broadened size distribution and atypical temperature dependent emission energy and linewidth. -- Highlights: • InAs quantum dots on different Ga(In)As surrounding material were grown by molecular beam epitaxy. • Optical investigation was used to study the impact of InAs QDs' position within InGaAs strain reducing layer with lower indium concentration. • Atomic force microscope images have been employed for the analyses of the optical results. • Indium segregation and strain driven alloy phase separation have been observed to affect both the QDs and their surrounding material. • QDs' emission wavelengths in the International Telecommunication Union O-band at room temperature have been obtained

  3. Testing and Implementation Progress on the Advanced Photon Source (APS) Linear Accelerator (Linac) High-Power S-band Switching System

    CERN Document Server

    Grelick, A E; Berg, S; Dohan, D A; Goeppner, G A; Kang, Y W; Nassiri, A; Pasky, S; Pile, G; Smith, T; Stein, S J

    2000-01-01

    An S-band linear accelerator is the source of particles and the front end of the Advanced Photon Source injector. In addition, it supports a low-energy undulator test line (LEUTL) and drives a free-electron laser (FEL). A waveguide-switching and distribution system is now under construction. The system configuration was revised to be consistent with the recent change to electron-only operation. There are now six modulator-klystron subsystems, two of which are being configured to act as hot spares for two S-band transmitters each, so that no single failure will prevent injector operation. The two subsystems are also used to support additional LEUTL capabilities and off-line testing. Design considerations for the waveguide-switching subsystem, topology selection, control and protection provisions, high-power test results, and current status are described

  4. Progress in high-efficient solution process organic photovoltaic devices fundamentals, materials, devices and fabrication

    CERN Document Server

    Li, Gang

    2015-01-01

    This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process fo...

  5. Advances in materials science, metals and ceramics division. Triannual progress report, June-September 1980

    International Nuclear Information System (INIS)

    Information is presented concerning the magnetic fusion energy program; the laser fusion energy program; geothermal research; nuclear waste management; Office of Basic Energy Sciences (OBES) research; diffusion in silicate minerals; chemistry research resources; and chemistry and materials science research

  6. Progress report: Chemistry and Materials Division, 1983 January 1 - June 30

    International Nuclear Information System (INIS)

    The research progams in solid state science, analytical and physical chemistry and materials science are outlined for the first half of 1983. Studies are being carried out in the areas of surface science, isotope separation and irradiation effects on zirconium

  7. SANS-polymer and functional materials with neutron in Indonesia. Progress report on the collaboration activities?

    International Nuclear Information System (INIS)

    Activities on SANS-polymer collaboration program are reported. This paper presents SANS-data from Sodium Dodecyl Sulphate that have been obtained using BATAN's SANS machine in Serpong. Reports are also presented about activities in the groups for functional materials structural determination which includes magnetic, HTc superconducting and superionic conducting materials. Discussions are also given towards the way the collaboration activities were carried out in the last three years as well as impact of neutron scattering facility conditions in Indonesia. (author)

  8. Heavy vehicle propulsion system materials program semiannual progress report for April 1999 through September 1999

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R.

    2000-01-01

    The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks.

  9. Building thermal envelope systems and materials (BTESM) progress report for DOE Office of Buildings Energy Research

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G. (comp.)

    1990-10-01

    The Monthly Report of the Building Thermal Envelope Systems and Materials (BTESM) Program is a monthly update of both in-house ORNL projects and subcontract activities in the research areas of building materials, wall systems, foundations, roofs, and building diagnostics. Presentations are not stand-alone paragraphs every month. Their principal values are the short-time lapse between accomplishment and reporting and their evolution over a period of several months.

  10. Progress in the chemistry of chromium(V) doping agents used in polarized target materials

    Energy Technology Data Exchange (ETDEWEB)

    Krumpolc, M. (Illinois Univ., Chicago, IL (USA)); Hill, D. (Argonne National Lab., IL (USA)); Struhrmann, H.B. (Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany, F.R.). Hamburger Synchrotronstrahlungslabor)

    1990-01-01

    We wish to report progress in two areas of the chromium (V)-based doping agents: Two commonly used chromium (V) complexes, I and II, have been synthesized in perdeuterated form (i.e., all hydrogens replaced by deuterium). They are sodium bis(2-ethyl-2-deuteroxy-butyrato)oxochromate(V)monodeuterate, IV, (acronym EDBA-Cr(V)), and sodium bis(2-deuteroxy-2-methylpropionato)oxochromate(V), III, (acronym DMPA-Cr(V)). A synthetic route leading to the preparation of stable, chromium(III)-free solutions of chromium(V) in diols (1,2-ethanediol/ethylene glycol/and 1,2-propanediol/propylene glycol/) has been outlined.

  11. Heavy Vehicle Propulsion System Materials Program Semiannual Progress Report for October 1998 Through March 1999

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.D.

    1999-06-01

    The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks. The Office of Transportation Technologies, Office of Heavy Vehicle Technologies (OIT OHVT) has an active program to develop the technology for advanced LE-55 diesel engines with 55% efficiency and low emissions levels of 2.0 g/bhp-h NOX and 0.05 g/bhp-h particulate. The goal is also for the LE-55 engine to run on natural gas with efficiency approaching that of diesel fuel. The LE-55 program is being completed in FY 1997 and, after approximately 10 years of effort, has largely met the program goals of 55% efficiency and low emissions. However, the commercialization of the LE-55 technology requires more durable materials than those that have been used to demonstrate the goals. Heavy Vehicle Propulsion System Materials will, in concert with the heavy duty diesel engine companies, develop the durable materials required to commercialize the LE-55 technologies. OIT OHVT also recognizes a significant opportunity for reduction in petroleum consumption by dieselization of pickup trucks, vans, and sport utility vehicles. Application of the diesel engine to class 1,2, and 3 trucks is expected to yield a 35% increase in fuel economy per vehicle. The foremost barrier to diesel use in this market is emission control. Once an engine is made certifiable, subsequent challenges will be in cost; noise, vibration, and harshness (NVH); and performance. The design of advanced components for high-efficiency diesel engines has, in some cases, pushed the performance envelope for materials of construction past the point of reliable operation. Higher mechanical and

  12. Development of FeCoB/Graphene Oxide based microwave absorbing materials for X-Band region

    International Nuclear Information System (INIS)

    This work explored the microwave absorption capability of Graphene Oxide and Graphene Oxide coated with FeCoB for stealth technology. Epoxy based microwave absorbing materials were prepared with 30% loading of Graphene Oxide, FeCoB alloy and Graphene Oxide coated with FeCoB. Graphene Oxide and FeCoB were synthesized by Hummer's and Co-precipitation methods, respectively. The filler particles were characterized by FESEM, XRD and Vibrating Sample Magnetometer techniques. Permittivity, permeability and reflection loss values of the composite absorbers were measured with vector network analyzer which showed a reflection loss value of −7.86 dB, at 10.72 GHz, for single layered Graphene Oxide/Epoxy based microwave absorbers which can be correlated to the absorption of about 83.97% of the incident microwave energy. Reflection loss value of FeCoB/Epoxy based microwave absorber showed −13.30 dB at 11.67 GHz, which corresponded to maximum absorption of 93.8%. However, reflection loss values of Graphene Oxide coated with FeCoB/Epoxy based single-layer absorber increased to −22.24 dB at 12.4 GHz which corresponds to an absorption of 99% of the incident microwave energy. - Highlights: • FeCoB coated Graphene Oxide (GO) was synthesized by co-precipitation method. • GO, FeCoB and GO@FeCoB based microwave absorbers were developed with Epoxy matrix. • GO and FeCoB/Epoxy absorbers showed −7.86 & −13.30 dB reflection loss, respectively. • Maximum Reflection loss of −22.24 dB was achieved with GO@FeCoB/Epoxy absorber

  13. Heavy vehicle propulsion system materials program semiannual progress report for April 1998 thru September 1998

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R.

    1999-01-01

    The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1--3 trucks to realize a 35{percent} fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7--8 trucks. The Office of Transportation Technologies, Office of Heavy Vehicle Technologies (OTT OHVT) has an active program to develop the technology for advanced LE-55 diesel engines with 55{percent} efficiency and low emissions levels of 2.0 g/bhp-h NO{sub x} and 0.05 g/bhp-h particulates. The goal is also for the LE-55 engine to run on natural gas with efficiency approaching that of diesel fuel. The LE-55 program is being completed in FY 1997 and, after approximately 10 years of effort, has largely met the program goals of 55{percent} efficiency and low emissions. However, the commercialization of the LE-55 technology requires more durable materials than those that have been used to demonstrate the goals. Heavy Vehicle Propulsion System Materials will, in concert with the heavy-duty diesel engine companies, develop the durable materials required to commercialize the LE-55 technologies.

  14. Progress in the electrochemical modification of graphene-based materials and their applications

    International Nuclear Information System (INIS)

    Highlights: • Six means of functionalizing graphene electrochemically is reviewed. • Electrochemical functionalization is relatively new to other standard methods. • The technique is expected to improve graphene's application range considerably. -- Abstract: Graphene is a 2D allotrope of carbon with exciting properties such as extremely high electronic conductivity and superior mechanical strength. It has considerable potential for applications in fields such as bio-sensors, electrochemical energy storage and electronics. In most cases, graphene has been functionalized and modified with other materials to prepare composites. This work reviews the electrochemical modification of graphene. Commencing with a brief history, a summary of several different means of modifying graphene to effect diverse applications is provided. This is followed by a discussion on different composite materials that have been prepared with reduced graphene oxide prior to moving onto a detailed consideration of six different methods of electrochemically modifying graphene to prepare composite materials. These methods involve cathodic reduction of graphene oxide, electrophoretic deposition, electro-deposition techniques, electrospinning, electrochemical doping and electrochemical polymerization. Finally a consideration on the applications of electrochemically modified graphene composite materials in various fields is presented prior to discussing some prospects in enhancing the electrochemical process to realize excellent and economic composite materials in bulk

  15. Progress on materials and scaffold fabrications applied to esophageal tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Qiuxiang; Shi, Peina; Gao, Mongna; Yu, Xuechan; Liu, Yuxin; Luo, Ling; Zhu, Yabin, E-mail: zhuyabin@nbu.edu.cn

    2013-05-01

    The mortality rate from esophageal disease like atresia, carcinoma, tracheoesophageal fistula, etc. is increasing rapidly all over the world. Traditional therapies such as surgery, radiotherapy or chemotherapy have been met with very limited success resulting in reduced survival rate and quality of patients' life. Tissue-engineered esophagus, a novel substitute possessing structure and function similar to native tissue, is believed to be an effective therapy and a promising replacement in the future. However, research on esophageal tissue engineering is still at an early stage. Considerable research has been focused on developing ideal scaffolds with optimal materials and methods of fabrication. This article gives a review of materials and scaffold fabrications currently applied in esophageal tissue engineering research. - Highlights: ► Natural and synthesized materials are being developed as scaffold matrices. ► Several technologies have been applied to reconstruct esophagus tissue scaffold. ► Tissue-engineered esophagus is a promising artificial replacement.

  16. History, progress, achievement and future prospect of research activities on fusion materials by Japanese university researchers

    International Nuclear Information System (INIS)

    Research activities on fusion materials by Japanese university researchers are reviewed. Organized research on fusion materials has been initiated around mid 1970s under auspices of Monbusho (Ministry of Education, Science and Culture). Particularly effective was the Special Research Project on Fusion for fiscal year 1980 - 1989. At the same time, Japan/U.S. collaboration on fusion materials (1982 - 2000) has been very successful, yielding numerous useful results. The highlights of the technical achievement of these projects are briefly summarized. Both of these projects may be characterized to be composed of two major tasks, namely, fundamental aspects of alloy development for fusion and high fluence irradiation effects under fusion reactor environment. The basic philosophy of the project is discussed. The recent trend is to organize the university research activities into a comprehensive research network. (orig.)

  17. Recent progress in the growth and applications of graphene as a smart material: A review

    Directory of Open Access Journals (Sweden)

    Brahim eAissa

    2015-09-01

    Full Text Available Innovative breakthroughs in fundamental research and industrial applications of graphene material have made its mass and low-cost production a necessary step toward its real world applications. This one-atom thick crystal of carbon, gathers a set of unique physico-chemical properties, ranging from its extreme mechanical behavior to its exceptional electrical and thermal conductivities, which are making graphene as a serious alternative to replace many conventional materials for various applications. In this review paper, we highlight the most important experimental results on the synthesis of graphene material, its emerging properties with reference to its smart applications. We discuss the possibility to successfully integrating graphene directly into device, enabling thereby the realization of a wide range of applications, including actuation, photovoltaic, thermoelectricity, shape memory, self-healing, electrorheology and space missions. The future outlook of graphene is also considered and discussed.

  18. Recent progress in the growth and applications of graphene as a smart material: A review

    Science.gov (United States)

    Aissa, Brahim; Memon, Nasir; Ali, Adnan; Khraisheh, Marwan

    2015-09-01

    Innovative breakthroughs in fundamental research and industrial applications of graphene material have made its mass and low-cost production a necessary step toward its real world applications. This one-atom thick crystal of carbon, gathers a set of unique physico-chemical properties, ranging from its extreme mechanical behavior to its exceptional electrical and thermal conductivities, which are making graphene as a serious alternative to replace many conventional materials for various applications. In this review paper, we highlight the most important experimental results on the synthesis of graphene material, its emerging properties with reference to its smart applications. We discuss the possibility to successfully integrating graphene directly into device, enabling thereby the realization of a wide range of applications, including actuation, photovoltaic, thermoelectricity, shape memory, self-healing, electrorheology and space missions. The future outlook of graphene is also considered and discussed.

  19. Helium generation in fusion reactor materials. Technical progress report, April--September 1977

    International Nuclear Information System (INIS)

    The near-term objectives of this program are to measure the spectrum-integrated helium generation rates and cross sections of a number of pure elements and alloys in several high-intensity neutron sources, and to develop and demonstrate neutron dosimetry procedures using some of these materials. To this end, four neutron irradiation experiments have now been run: one using accelerator-produced d-Be neutrons, two using the accelerator-produced d-T reaction, and one in the neutron field of a mixed-spectrum fission reactor. All of these irradiations have incorporated a large number of helium-generation materials

  20. Progress in nanofiltration membrane materials%纳滤膜材料研究进展

    Institute of Scientific and Technical Information of China (English)

    李祥; 张忠国; 任晓晶; 李继定

    2014-01-01

    The characteristics and applications of nanofiltration membranes are briefly introduced. Common organic polymer nanofiltration membrane materials are reviewed,including cellulose acetate and aromatic polyamide,novel nanofiltration membrane materials covering natural polymer and polyelectrolyte , inorganic nanofiltration materials and inorganic-organic hybrid composite nanofiltration membrane materials. For these membrane materials,structural characteristics,chemical properties , membrane fabrication processes and applications are contrastingly analyzed and summarized from different perspectives,including high flux,resistance to pollution,organic solvent resistance and chlorine resistance. Then development trends and application prospects of nanofiltration membrane materials are predicted. And in the immediate future,two issues will become hot topics of research. One is the development and structure control of high-performance nanofiltration membrane materials;the other is the design of structure and function with different nanofiltration membrane materials matrixes.%简单阐述了纳滤膜的特点与应用,综述了乙酸纤维类、芳香族聚酰胺类等常用有机高分子纳滤膜材料,天然高分子、聚电解质等新型有机高分子纳滤膜材料,无机纳滤膜材料以及无机-有机杂化复合纳滤膜材料的研究进展。分别列举了相应膜材料的典型膜,并从高通量、抗污染、耐有机溶剂与耐氯性等多角度对相应膜材料的结构特性、化学特性、膜制备技术与应用特点进行了对比分析与总结,最后对纳滤膜材料的发展趋势与应用前景作了预测与展望,指出特种高性能纳滤膜材料的开发与微观结构的调控和基于不同纳滤膜材料的结构与功能设计将成为今后一段时间内的研究热点。

  1. Progress report, Chemistry and Materials Division, April 1 to June 30, 1977

    International Nuclear Information System (INIS)

    Research results are reported in such areas as ion penetration, electron microscopy, metal physics and radiation damage, nuclear methods of analysis, fuel analysis, and general analytical chemistry, electrochemistry, radiation chemistry, hydrogen-deuterium exchange, and surface chemistry of nuclear materials like zirconium base alloys. (E.C.B.)

  2. Electromagnetic material changes for remote detection and monitoring: a feasibility study: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Jordan, David V.; Kelly, James F.; McMakin, Douglas L.; Johnson, Bradley R.; Campbell, Luke W.

    2009-09-01

    A new concept for radiation detection is proposed, allowing a decoupling of the sensing medium and the readout. An electromagnetic material, such as a magnetic ceramic ferrite, is placed near a source to be tracked such as a shipping container. The electromagnetic material changes its properties, in this case its magnetic permeability, as a function of radiation. This change is evident as a change in reflection frequency and magnitude when probed using a microwave/millimeter-wave source. This brief report discusses modeling of radiation interaction of various candidate materials using a radiation detector modeling code Geant4, system design considerations for the remote readout, and some theory of the material interaction physics. The theory of radiation change in doped magnetic insulator ferrites such as yttrium iron garnet (YIG) seems well founded based on literature documentation of the photomagnetic effect. The literature also suggests sensitivity of permittivity to neutrons in some ferroelectrics. Research to date indicates that experimental demonstration of these effects in the context of radiation detection is warranted.

  3. Progress report, Chemistry and Materials Division, October 1 to December 31, 1975

    International Nuclear Information System (INIS)

    Interim research results are reported in solid state science (ion penetration, electron microscopy, radiation damage and metal physics, nuclear methods of analysis), general chemistry (analytical chemistry, hydrogen-water exchange, radioactivity measurements, electrochemistry), physical chemistry (radiation and isotope chemistry), materials science (surface chemistry and metal physics), and university research (deuterium exchange and zirconium alloy properties). (E.C.B.)

  4. Progress report chemistry and materials division 1984 January 1 - June 30

    International Nuclear Information System (INIS)

    During the first half of 1984 work in the Chemistry and Materials Division of Chalk River Nuclear Laboratories concentrated on studies of ion penetration phenomena, surface phenomena, radiation damage, radiochemical analysis, recycle fuel analysis, gamma spectrometry, mass spectrometry of fuels and moderators, analysis of hydrogen in zirconium alloys, burnup analysis, radiolysis, hydrogen isotope separation, hydrogen adsorption, zirconium corrosion, and metal physics studies of zirconium

  5. Recent progress in transparent conducting materials by use of metallic grids on metaloxides

    NARCIS (Netherlands)

    Deelen, J. van; Rendering, H.; Hovestad, A.

    2012-01-01

    Alternatives to ITO are under heavy investigation. Organic and inorganic transparent conducting materials are compared based on their transparency versus sheet resistance characteristics. Although graphene has advanced recently, TCOs are still superior in performance and can only be surpassed by the

  6. Recent progress in mesoporous titania materials: adjusting morphology for innovative applications

    Directory of Open Access Journals (Sweden)

    Juan L Vivero-Escoto, Ya-Dong Chiang, Kevin C-W Wu and Yusuke Yamauchi

    2012-01-01

    Full Text Available This review article summarizes recent developments in mesoporous titania materials, particularly in the fields of morphology control and applications. We first briefly introduce the history of mesoporous titania materials and then review several synthesis approaches. Currently, mesoporous titania nanoparticles (MTNs have attracted much attention in various fields, such as medicine, catalysis, separation and optics. Compared with bulk mesoporous titania materials, which are above a micrometer in size, nanometer-sized MTNs have additional properties, such as fast mass transport, strong adhesion to substrates and good dispersion in solution. However, it has generally been known that the successful synthesis of MTNs is very difficult owing to the rapid hydrolysis of titanium-containing precursors and the crystallization of titania upon thermal treatment. Finally, we review four emerging fields including photocatalysis, photovoltaic devices, sensing and biomedical applications of mesoporous titania materials. Because of its high surface area, controlled porous structure, suitable morphology and semiconducting behavior, mesoporous titania is expected to be used in innovative applications.

  7. Analyzing Students' Learning Progressions Throughout a Teaching Sequence on Acoustic Properties of Materials with a Model-Based Inquiry Approach

    Science.gov (United States)

    Hernández, María Isabel; Couso, Digna; Pintó, Roser

    2015-04-01

    The study we have carried out aims to characterize 15- to 16-year-old students' learning progressions throughout the implementation of a teaching-learning sequence on the acoustic properties of materials. Our purpose is to better understand students' modeling processes about this topic and to identify how the instructional design and actual enactment influences students' learning progressions. This article presents the design principles which elicit the structure and types of modeling and inquiry activities designed to promote students' development of three conceptual models. Some of these activities are enhanced by the use of ICT such as sound level meters connected to data capture systems, which facilitate the measurement of the intensity level of sound emitted by a sound source and transmitted through different materials. Framing this study within the design-based research paradigm, it consists of the experimentation of the designed teaching sequence with two groups of students ( n = 29) in their science classes. The analysis of students' written productions together with classroom observations of the implementation of the teaching sequence allowed characterizing students' development of the conceptual models. Moreover, we could evidence the influence of different modeling and inquiry activities on students' development of the conceptual models, identifying those that have a major impact on students' modeling processes. Having evidenced different levels of development of each conceptual model, our results have been interpreted in terms of the attributes of each conceptual model, the distance between students' preliminary mental models and the intended conceptual models, and the instructional design and enactment.

  8. Review of Recent Progress of Plasmonic Materials and Nano-Structures for Surface-Enhanced Raman Scattering

    Directory of Open Access Journals (Sweden)

    Alan X. Wang

    2015-05-01

    Full Text Available Surface-enhanced Raman scattering (SERS has demonstrated single-molecule sensitivity and is becoming intensively investigated due to its significant potential in chemical and biomedical applications. SERS sensing is highly dependent on the substrate, where excitation of the localized surface plasmons (LSPs enhances the Raman scattering signals of proximate analyte molecules. This paper reviews research progress of SERS substrates based on both plasmonic materials and nano-photonic structures. We first discuss basic plasmonic materials, such as metallic nanoparticles and nano-rods prepared by conventional bottom-up chemical synthesis processes. Then, we review rationally-designed plasmonic nano-structures created by top-down approaches or fine-controlled synthesis with high-density hot-spots to provide large SERS enhancement factors (EFs. Finally, we discuss the research progress of hybrid SERS substrates through the integration of plasmonic nano-structures with other nano-photonic devices, such as photonic crystals, bio-enabled nanomaterials, guided-wave systems, micro-fluidics and graphene.

  9. The Effect of Scale Dependent Discretization on the Progressive Failure of Composite Materials Using Multiscale Analyses

    Science.gov (United States)

    Ricks, Trenton M.; Lacy, Thomas E., Jr.; Pineda, Evan J.; Bednarcyk, Brett A.; Arnold, Steven M.

    2013-01-01

    A multiscale modeling methodology, which incorporates a statistical distribution of fiber strengths into coupled micromechanics/ finite element analyses, is applied to unidirectional polymer matrix composites (PMCs) to analyze the effect of mesh discretization both at the micro- and macroscales on the predicted ultimate tensile (UTS) strength and failure behavior. The NASA code FEAMAC and the ABAQUS finite element solver were used to analyze the progressive failure of a PMC tensile specimen that initiates at the repeating unit cell (RUC) level. Three different finite element mesh densities were employed and each coupled with an appropriate RUC. Multiple simulations were performed in order to assess the effect of a statistical distribution of fiber strengths on the bulk composite failure and predicted strength. The coupled effects of both the micro- and macroscale discretizations were found to have a noticeable effect on the predicted UTS and computational efficiency of the simulations.

  10. Heavy vehicle propulsion system materials program: Semiannual progress report, April 1996--September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R.

    1997-04-01

    The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks. The Office of Transportation Technologies, Office of Heavy Vehicle Technologies (OTT OHVT) has an active program to develop the technology for advanced LE-55 diesel engines with 55% efficiency and low emissions levels of 2.0 g/bhp-h NO{sub x} and 0.05 g/bhp-h particulates. The goal is also for the LE-55 engine to run on natural gas with efficiency approaching that of diesel fuel. The LE-55 program is being completed in FY 1997 and, after approximately 10 years of effort, has largely met the program goals of 55% efficiency and low emissions. However, the commercialization of the LE-55 technology requires more durable materials than those that have been used to demonstrate the goals. Heavy Vehicle Propulsion System Materials will, in concert with the heavy duty diesel engine companies, develop the durable materials required to commercialize the LE-55 technologies. OTT OHVT also recognizes a significant opportunity for reduction in petroleum consumption by dieselization of pickup trucks, vans, and sport utility vehicles. Application of the diesel engine to class 1, 2, and 3 trucks is expected to yield a 35% increase in fuel economy per vehicle. The foremost barrier to diesel use in this market is emission control. Once an engine is made certifiable, subsequent challenges will be in cost; noise, vibration, and harshness (NVH); and performance. Separate abstracts have been submitted to the database for contributions to this report.

  11. Propulsion system materials program. Semiannual progress report, October 1995--March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R.

    1996-07-01

    This portion of the program is identified as program element 1.0 within the work breakdown structure (WBS). It contains five subelements: (1) Monolithics, (2) Ceramic Composites, (3) Thermal and Wear Coatings, (4) Joining, and (5) Ceramic Machining. Ceramic research conducted within the Monolithics subelement currently includes work activities on low Cost Si{sub 3}N{sub 4} powder, green state ceramic fabrication, characterization, and densification, and on structural, mechanical, and physical properties of these ceramics. Research conducted within the Ceramic Composites subelement currently includes silicon nitride and oxide-based composites, and low expansion materials. Research conducted in the Thermal and Wear Coatings subelement is currently limited to oxide-based coatings and involves coating synthesis, characterization, and determination of the mechanical and physical properties of the coatings. Research conducted in the Joining subelement currently includes studies of processes to produce strong, stable joints between zirconia ceramics and iron-base alloys. As part of an expanded effort to reduce the cost of ceramic components, a new initiative in cost effective machining has been started. A major objective of the research in the Materials and Processing program element is to systematically advance the understanding of the relationships between ceramic raw materials such as powders and reactant gases, the processing variables involved in producing the ceramic materials, and the resultant microstructures and physical and mechanical properties of the ceramic materials. Success in meeting this objective will provide U.S. companies with new or improved ways for producing economical, highly reliable ceramic components for advanced heat engines.

  12. Gastric Banding

    Science.gov (United States)

    ... gastric banding before deciding to have the procedure. Advertisements for a device or procedure may not include ... feeds Follow FDA on Twitter Follow FDA on Facebook View FDA videos on YouTube View FDA photos ...

  13. Progress towards fabrication of Th:229-doped high energy band-gap crystals for use as a solid-state optical frequency reference

    CERN Document Server

    Rellergert, Wade G; DeMille, D; Greco, R R; Hehlen, M P; Jackson, R A; Torgerson, J R; Hudson, Eric R

    2010-01-01

    We have recently described a novel method for the construction of a solid-state optical frequency reference based on doping $^{229}$Th into high energy band-gap crystals. Since nuclear transitions are far less sensitive to environmental conditions than atomic transitions, we have argued that the $^{229}$Th optical nuclear transition may be driven inside a host crystal resulting in an optical frequency reference with a short-term stability of $3\\times10^{-17}<\\Delta f/f <1\\times10^{-15}$ at 1 s and a systematic-limited repeatability of $\\Delta f/f \\sim 2 \\times 10^{-16}$. Improvement by $10^2-10^3$ of the constraints on the variability of several important fundamental constants also appears possible. Here we present the results of the first phase of these experiments. Specifically, we have evaluated several high energy band-gap crystals (Th:NaYF, Th:YLF, Th:LiCAF, Na$_2$ThF$_6$, LiSAF) for their suitability as a crystal host by a combination of electron beam microprobe measurements, Rutherford Backscatte...

  14. Metals and Ceramics Division materials science program. Annual progress report for period ending June 30, 1981

    International Nuclear Information System (INIS)

    Information is presented concerning the theoretical studies of metals and alloys; x-ray diffraction research; structural ceramics; structure of coal; analytical and high-voltage electron microscopy; deformation and mechanical properties; mechanisms of surface and solid-state reactions; physical properties research; metastable materials; neutron radiation effects; charged particle radiation effects; theory and modeling of radiation effects; facility and advanced technique development; fundamentals of welding and joining; and studies in nondestructive evaluation

  15. Progress in the investigation of the longevity of Portland cement grout seal materials

    International Nuclear Information System (INIS)

    The sealing of openings in underground repositories and the assessment of the potential for seal materials to perform acceptably for long periods of time are concerns shared by programs considering the deep disposal of nuclear waste. Two grouting materials, bentonite and portland cement, have been identified by many programs as likely candidate seal materials. As a part of Phase III of the Stripa Project, the longevity of both of these materials is being investigated in a series of coordinated laboratory, modeling, and field studies. Long-term performance is an important issue particularly for cement, since most solid phases in cement are metastable, and therefore it is likely that cement seal performance would degrade with time. In this investigation, geochemical and permeability modeling have been used together to estimate how long cement seals may be expected to perform acceptably. Analyses to assess cement degradation due to phase inversion and dissolution have been performed; for dissolution calculations, both slow flow and fast flow hydrologic systems have been analyzed to establish bounding conditions. Actual granitic terrain grounwater compositions ranging from fresh to saline have been used to calculate cement-groundwater interactions. A relationship between cement permeability and porosity has been developed based on empirical data. Changes in performance with time have been predicted by conservatively estimating hydrologic conditions at successive stages of post-closure repository history. For the conditions considered, preliminary results indicate that the single largest determinant of seal performance is the initial hydraulic conductivity of the cement. Based on this investigation, cement grout performance may be acceptable for very long periods of time (tens of thousands to millions of years) providing its initial conductivity is on the order of 10-12 m/s

  16. Enforcement actions: Significant actions resolved material licensees. Semiannual progress report, July--December 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This compilation summarizes significant enforcement actions that have been resolved during the period and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication.

  17. Enforcement actions: Significant actions resolved material licensees. Semiannual progress report, July--December 1996

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during the period and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  18. Evaluating the progress of the UK's Material Recycling Facilities: a mini review.

    Science.gov (United States)

    Ali, Muhammad; Courtenay, Peter

    2014-12-01

    Over the last 15 years, the UK has made great strides in reducing the amount of waste being sent to landfill while also increasing the amount of waste being recycled. The key drivers for this change are the European Union Landfill Directive (1999/31/EC) and the UK Landfill Tax. However, also playing their part are the growing numbers of Material Recycling Facilities (MRFs), which process recyclables. This mini review evaluates the current state of MRFs in the UK, through extensive secondary research, and detailed primary data analysis focussing on MRFs located in South-East England, UK. This study also explores technologies that aim to generate energy from waste, including Waste-to-Energy (WtE) and Refuse-derived Fuel (RDF) facilities. These facilities can have a huge appetite for waste, which can be detrimental to recycling efforts as some of the waste being sent there should be recycled. It was found that the waste sent to a typical UK MRF would recycle around 92% of materials while 6% was sent to energy recovery and the remaining 2% ended up in landfill. Therefore, the total estimated rejected or non-compliance materials from MRFs are around 8%. A key recommendation from this study is to adopt a strategy to combine MRFs with a form of energy generation, such as WtE or RDF. This integrated approach would ensure any residual waste arising from the recycling process can be used as a sustainable fuel, while also increasing the recycling rates.

  19. Evaluating the progress of the UK's Material Recycling Facilities: a mini review.

    Science.gov (United States)

    Ali, Muhammad; Courtenay, Peter

    2014-12-01

    Over the last 15 years, the UK has made great strides in reducing the amount of waste being sent to landfill while also increasing the amount of waste being recycled. The key drivers for this change are the European Union Landfill Directive (1999/31/EC) and the UK Landfill Tax. However, also playing their part are the growing numbers of Material Recycling Facilities (MRFs), which process recyclables. This mini review evaluates the current state of MRFs in the UK, through extensive secondary research, and detailed primary data analysis focussing on MRFs located in South-East England, UK. This study also explores technologies that aim to generate energy from waste, including Waste-to-Energy (WtE) and Refuse-derived Fuel (RDF) facilities. These facilities can have a huge appetite for waste, which can be detrimental to recycling efforts as some of the waste being sent there should be recycled. It was found that the waste sent to a typical UK MRF would recycle around 92% of materials while 6% was sent to energy recovery and the remaining 2% ended up in landfill. Therefore, the total estimated rejected or non-compliance materials from MRFs are around 8%. A key recommendation from this study is to adopt a strategy to combine MRFs with a form of energy generation, such as WtE or RDF. This integrated approach would ensure any residual waste arising from the recycling process can be used as a sustainable fuel, while also increasing the recycling rates. PMID:25391552

  20. Progress report: Chemistry and Materials Division, 1982 April 1 - June 30

    International Nuclear Information System (INIS)

    The work of the division in the areas of solid state studies, radiation chemistry, isotope separation, analytical chemistry and materials science is described. The solid state science group studied solute atom vacancy trapping in irradiated f.c.c. alloys as well as the rearrangement of atoms in solids bombarded by energetic heavy ions. In radiation chemistry, work was done on the pulse radiolysis of NO in argon. Isotope separation studies were done on fluoroform and uranium. Fuel burnup determination using 148Nd and 139La was investigated. Zirconium alloy studies included work on stress corrosion cracking and the Baushinger effect

  1. Evaluating the progress of the UK’s material recycling facilities:a mini review

    OpenAIRE

    Ali, Muhammad; Courtenay, Peter

    2014-01-01

    Over the last 15 years, the UK has made great strides in reducing the amount of waste being sent to landfill while also increasing the amount of waste being recycled. The key drivers for this change are the European Union Landfill Directive (1999/31/EC) and the UK Landfill Tax. However, also playing their part are the growing numbers of Material Recycling Facilities (MRFs), which process recyclables. This mini review evaluates the current state of MRFs in the UK, through extensive secondary r...

  2. Magneto-optical spectroscopy of d- and f-ferromagnetic materials: recent theoretical progress (Review article)

    International Nuclear Information System (INIS)

    The current status of theoretical understanding of the optical and magneto-optical (MO) spectra of 3d, 4f and 5f compounds is reviewed. Energy band theory based upon the local spin-density approximation (LSDA) describes the optical and MO spectra of transition metal compounds reasonably well. Examples which we examine in detail are XPt3 compounds (with X=sd V,Cr, Mn,Fe and Co) in the AuCu3 structure, ternary Heusler alloys NiMnSb, PdMnSb, PtMnSb and MnBi compound. The LSDA, which is capable of describing the spectra of transition metal alloys with high accuracy, does not suffice for lanthanide compounds having a correlated 4f shell. A satisfactory description of the optical spectra could be obtained by using a generalization of the LSDA, in which explicitly f electron coulomb correlations are taken into account (LSDA+U approach). As examples of this group we consider CeSb and CeBi. For CeSb a record Kerr angle of 90 degree was very recently reported, 90 degree is the absolute maximum value that can be measured. It is two orders of magnitude larger than the values that are commonly measured for transition-metal compounds, and about one order of magnitude larger than values maximally achieved for other lanthanide and actinide compounds. A third group consist of uranium 5f compounds. In those compounds where the 5f electrons are rather delocalized, the LSDA describes the MO spectra reasonably well. As examples of this group we consider UAsSe and URhAl. Particular difficulties occur for the uranium compounds where the 5f electrons are neither delocalized nor localized, but more ore less semi localized. Typical examples are US,Use and UTe. The semi localized 5f's are however, not inert, but their interaction with conduction electrons plays an important role. Recently achieved improvements for describing such compounds are discussed

  3. Research progress of cholesteric liquid crystals with broadband reflection characteristics in application of intelligent optical modulation materials

    Science.gov (United States)

    Zhang, Lan-Ying; Gao, Yan-Zi; Song, Ping; Wu, Xiao-Juan; Yuan, Xiao; He, Bao-Feng; Chen, Xing-Wu; Hu, Wang; Guo, Ren-Wei; Ding, Hang-Jun; Xiao, Jiu-Mei; Yang, Huai

    2016-09-01

    Cholesteric liquid crystals (CLCs) have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship. Nowadays, by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution, extensive work has already been performed to obtain CLC films with a broad reflection band. Based on authors’ many years’ research experience, this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics, methods to obtain broadband reflection of CLCs, as well as the application in the field of intelligent optical modulation materials. Combined with the research status and the advantages in the field, the important basic and applied scientific problems in the research direction are also introduced. Project supported by the National Natural Science Foundation of China (Grant Nos. 51573006, 51573003, 51203003, 51303008, 51302006, 51402006, 51272026, and 51273022), the Major Project of Beijing Science and Technology Program, China (Grant Nos. Z151100003315023 and Z141100003814011), and the Fok Ying Tung Education Foundation, China (Grant No. 142009).

  4. Colloquium: Topological band theory

    Science.gov (United States)

    Bansil, A.; Lin, Hsin; Das, Tanmoy

    2016-04-01

    The first-principles band theory paradigm has been a key player not only in the process of discovering new classes of topologically interesting materials, but also for identifying salient characteristics of topological states, enabling direct and sharpened confrontation between theory and experiment. This review begins by discussing underpinnings of the topological band theory, which involve a layer of analysis and interpretation for assessing topological properties of band structures beyond the standard band theory construct. Methods for evaluating topological invariants are delineated, including crystals without inversion symmetry and interacting systems. The extent to which theoretically predicted properties and protections of topological states have been verified experimentally is discussed, including work on topological crystalline insulators, disorder and interaction driven topological insulators (TIs), topological superconductors, Weyl semimetal phases, and topological phase transitions. Successful strategies for new materials discovery process are outlined. A comprehensive survey of currently predicted 2D and 3D topological materials is provided. This includes binary, ternary, and quaternary compounds, transition metal and f -electron materials, Weyl and 3D Dirac semimetals, complex oxides, organometallics, skutterudites, and antiperovskites. Also included is the emerging area of 2D atomically thin films beyond graphene of various elements and their alloys, functional thin films, multilayer systems, and ultrathin films of 3D TIs, all of which hold exciting promise of wide-ranging applications. This Colloquium concludes by giving a perspective on research directions where further work will broadly benefit the topological materials field.

  5. Research Progress on AgSbTe2-based Thermoelectric Materials

    Institute of Scientific and Technical Information of China (English)

    CAO Qigao; MA Guang; JIA Zhihua; ZHENG Jing; LI Jin

    2012-01-01

    Thermoelectric power generation represents a class of energy conversion technology,which has been used in power supply of aeronautic and astronautic exploring missions,now showing notable advantages to harvest the widely distributed waste heat and convert the abundant solar energy into electricity at lower cost than Si-based photovoltaic technology.Thermoelectric dimensionless figure of merit ZT plays a key role in the conversion efficiency from thermal to electrical energy.Low thermal conductivity and large Seebeck coefficient make the AgSbTe2 compound a very promising candidate for high efficiency p-type thermoelectric applications.The AgSbTe2-based thermoelectric system has been repeatedly studied as prospective thermoelectric materials.In this review,we firstly clarify some fundamental tradeoffs dictating the ZT value through the relationship ZT =S2σT/κ.We also pay special attentions to the recent advances in AgSbTe2-based thermoelectric materials.Finally,we provide an outlook of new directions in this filed.

  6. Progress report Chemistry and Materials Division, 1 April - 30 June, 1980

    International Nuclear Information System (INIS)

    By a combination of electrostatic and magnetic deflection it has been possible to examine the yield of ions scattered through 1800 from the surface region of a variety of solid targets. Progress has been made in establishing a basis for quantitative assay of multiple vacancy clusters around single solute atoms in dilute alloys. HF laser-induced decomposition of 2,2,2,-trifluoroethanol has been studied as a function of laser fluence. The oxidation of carbon monoxide adsorbed on the (111) crystal face of platinum has been investigated further. Vacuum pumping systems of the D/H mass spectrometers have been replaced with turbo-molecular pumping systems, reducing the HD+ background five-fold. Three iodine species, I-, I03-, and I04-, have been successfully separated and detected in aqueous solutions in the course of iodine specification studies. It has been shown that the occurrence of groups of grains with preferentially tangential basal poles serves to locate any radial hydrides at the inside surface of Zircaloy fuel cladding, but does not make any additional contribution to the susceptibility of the cladding to iodine induced stress corrosion cracking. The orientation relationships between oxide and metal on the (0001), (1120) and (1010) planes of zirconium single crystals show a different relationship for each of the principal planes. Further studies in the High Voltage Electron Microscope at AERE, Harwell confirm that electron irradiation produces only interstitial loops, and does not introduce -component dislocations in zirconium. The microtome has been improved to the point where layers of a ductile metal (zirconium) down to 70 nm can be reproducibly removed. (auth)

  7. Science of materials progress report, July 1, 1975--June 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-04-01

    Research in Metallurgy and Ceramics included the investigation of the mechanical properties, stress corrosion cracking, and fracture of metals, alloys, and transition metal compounds; the investigation of the dynamic structure of water and electrolyte solutions at high temperature and pressure; and the investigation of the properties of oxides and of the magnetic properties of alloys. Solid state Physics research was focussed on the electronic properties of solids and on defects in crystal structure including radiation damage. Important topics of investigation were the effect of dislocations and impurities on the mechanical properties of metals, diffusion processes in superionic conductors, the defect structure of quantum crystals, high pressure studies of the electronic structure of phosphors, and the magnetic structure of transition metal atoms in nonmagnetic host crystals. The program is planned to provide an atomic understanding of energy flow, conversion and storage processes, and to support with basic research the development of improved materials for energy applications.

  8. Science of materials progress report, July 1, 1975--June 30, 1976

    International Nuclear Information System (INIS)

    Research in Metallurgy and Ceramics included the investigation of the mechanical properties, stress corrosion cracking, and fracture of metals, alloys, and transition metal compounds; the investigation of the dynamic structure of water and electrolyte solutions at high temperature and pressure; and the investigation of the properties of oxides and of the magnetic properties of alloys. Solid state Physics research was focussed on the electronic properties of solids and on defects in crystal structure including radiation damage. Important topics of investigation were the effect of dislocations and impurities on the mechanical properties of metals, diffusion processes in superionic conductors, the defect structure of quantum crystals, high pressure studies of the electronic structure of phosphors, and the magnetic structure of transition metal atoms in nonmagnetic host crystals. The program is planned to provide an atomic understanding of energy flow, conversion and storage processes, and to support with basic research the development of improved materials for energy applications

  9. Materials research and beam line operation utilizing NSLS [National Synchrotron Light Source]: Progress report

    International Nuclear Information System (INIS)

    MATRIX is a group of scientists who have common interests in utilizing x-ray synchrotron radiation for materials research. This group has developed a specialized beam line (X-18A) for x-ray scattering studies at the National Synchrotron Light Source (NSLS). The beam line was designed to optimize experimental conditions for diffuse scattering and surface/interface studies. An extension of diffuse scattering to provide better quantitative data has been shown as well as a unique application to the solution of the phase problem. In the x-ray surface scattering area the first reported experiment to illustrate the capabilities for studying monolayers on water was performed. Current beam line upgrade projects are also described. In addition to a change to a UHV system and improvements dictated by operational experience, two new systems are described, a unique small angle scattering chamber (SAXS) for dynamic studies of nucleation and growth and a surface scattering chamber. 5 figs

  10. Progress report, Chemistry and Materials Division 1 July - 30 September, 1981

    International Nuclear Information System (INIS)

    The work of the division in the areas of solid state physics, chemistry and materials science over the quarter is described. The solid state science branch has worked on crystal defect formation after ion beam irradiation. Laser isotope separation methods have produced visible amounts of water enriched 2000-fold in deuterium. Work has been done on hydrogen isotope exchange in H2-methanol mixtures. Nitrogen impurities in Xe-133 can be determined down to the microgram level. A new apparatus for the determination of hydrogen in zirconium has been assembled. Coatings of stainless steels on zircaloy fuel cladding continue to offer protection against oxidation. Agreement has been obtained between computer-simulated and observed electron microscope images of irradiated titanium. Cold-worked zirconium has been studied under helium ion bombardment

  11. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, July 1, 1981-September 30, 1981

    International Nuclear Information System (INIS)

    Work covered in this report includes the activities associated with the status of the simulated reactor helium supply systems and testing equipment. The progress in the screening test program is described; this includes: screening creep results and metallographic analysis for materials thermally exposed or tested at 7500, 8500, 9500, and 10500C (13820, 15620, 17420, and 19220F). The status of controlled purity helium and air creep-rupture testing in the intensive screening test program is discussed. The results of metallographic studies of screening alloys exposed in controlled purity helium for 3000 hours at 7500C and 6000 hours at 8500C and for weldments exposed in controlled purity helium for 6000 hours at 8500 and 9500C are presented and discussed

  12. A Novel Approach to Materials Development for Advanced Reactor Systems. Quarterly Progress Report, Year 1; Quarter 4

    Energy Technology Data Exchange (ETDEWEB)

    Was, G.S.; Atzmon, M.; Wang, L.

    2000-09-28

    OAK B188 A Novel Approach to Materials Development for Advanced Reactor Systems. Quarterly Progress Report, Year 1; Quarter 4. Year one of this project had three major goals. First, to specify, order and install a new high current ion source for more rapid and stable proton irradiation. Second, to assess the use of chromium pre-enrichment and hardening by combining cold-work and irradiation in an effort to isolate a radiation damage microstructure in stainless steel without the effects of RIS. Third, to initiate irradiation of reactor pressure vessel steel and Zircaloy. In year 1 quarter 4, the project goal was to begin characterization of the microstructure of model alloys of RPV steels irradiated over a range of doses. We also planned to prepare samples for microstructure isolation in stainless steels, and to receive and characterize Zircaloy samples for subsequent irradiation.

  13. On the relationship between band broadening and the particle-size distribution of the packing material in liquid chromatography: theory and practice.

    Science.gov (United States)

    Gritti, Fabrice; Farkas, Tivadar; Heng, Josuah; Guiochon, Georges

    2011-11-11

    The influence of the particle size distribution (PSD) on the band broadening and the efficiency of packed columns is investigated on both theoretical and practical viewpoints. Each of the classical contributions to mass transfer kinetics, those due to longitudinal diffusion, eddy dispersion, and solid-liquid mass transfer resistance are measured and analyzed in terms of their expected and observed intensity as a function of the PSD of mixtures of the commercially available packing materials, 5 and 3 μm Luna-C₁₈ particles (Phenomenex, Torrance, CA, USA). Six 4.6 mm × 150 mm columns were packed with different mixtures of these two materials. The efficiencies of these columns were measured for a non-retained and a retained analytes in a mixture of acetonitrile and water. The longitudinal diffusion coefficient was directly measured by the peak parking method. The solid-liquid mass transfer coefficient was measured from the combination of the peak parking method, the best model of effective diffusion coefficient and the actual PSDs of the different particle mixtures measured by Coulter counter experiments. The eddy diffusion term was measured according to a recently developed protocol, by numerical integration of the peak profiles. Our results clearly show that the PSD has no measurable impact on any of the coefficients of the van Deemter equation. On the contrary and surprisingly, adding a small fraction of large particles to a batch of small particles can improve the quality of the packing of the fine particles. Our results indirectly confirm that the success of sub-3 μm shell particles is due to the roughness of their external surface, which contributes to eliminate most of the nefarious wall effects.

  14. Wide band gap materials and devices for NO{sub x}, H{sub 2} and O{sub 2} gas sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Majdeddin

    2008-01-22

    In this thesis, field effect gas sensors (Schottky diodes, MOS capacitors, and MOSFET transistors) based on wide band gap semiconductors like silicon carbide (SiC) and gallium nitride (GaN), as well as resistive gas sensors based on indium oxide (In{sub 2}O{sub 3}), have been developed for the detection of reducing gases (H{sub 2}, D{sub 2}) and oxidising gases (NO{sub x}, O{sub 2}). The development of the sensors has been performed at the Institute for Micro- and Nanoelectronic, Technical University Ilmenau in cooperation with (GE) General Electric Global Research (USA) and Umwelt-Sensor- Technik GmbH (Geschwenda). Chapter 1: serves as an introduction into the scientific fields related to this work. The theoretical fundamentals of solid-state gas sensors are provided and the relevant properties of wide band gap materials (SiC and GaN) are summarized. In chapter 2: The performance of Pt/GaN Schottky diodes with different thickness of the catalytic metal were investigated as hydrogen gas detectors. The area as well as the thickness of the Pt were varied between 250 {proportional_to} 250 {mu}m{sup 2} and 1000 {proportional_to} 1000 {mu}m{sup 2}, 8 and 40 nm, respectively. The response to hydrogen gas was investigated in dependence on the active area, the Pt thickness and the operating temperature for 1 vol.% hydrogen in synthetic air. We observed a significant increase of the sensitivity and a decrease of the response and recovery times by increasing the temperature of operation to about 350{sup o}C and by decreasing the Pt thickness down to 8 nm. Electron microscopy of the microstructure showed that the thinner platinum had a higher grain boundary density. The increase in sensitivity with decreasing Pt thickness points to the dissociation of molecular hydrogen on the surface, the diffusion of atomic hydrogen along the platinum grain boundaries and the adsorption of hydrogen at the Pt/GaN interface as a possible mechanism of sensing hydrogen by Schottky diodes. The

  15. Materials recycle and waste management in fusion power reactors. Progress report for 1982

    Energy Technology Data Exchange (ETDEWEB)

    Vogler, S.; Jung, J.; Steindler, M.J.; Maya, I.; Levine, H.E.; Peterman, D.D.; Strausburg, S.; Schultz, K.R.

    1983-01-01

    Several components of a STARFIRE fusion reactor have been studied. The breeding ratios were calculated as a function of lithium enrichment and neutron multiplier for systems containing either Li/sub 2/O or LiAlO/sub 2/. The lithium requirements for a fusion economy were also estimated for those cases and the current US resources were found to be adequate. However, competition with other lithium demands in the future emphasizes the need for recovering and reusing lithium. The radioactivities induced in the breeder and the impurities responsible for their formation were determined. The residual radioactivities of several low-activation structural materials were compared with the radioactivity from the prime candidate alloy (PCA) a titanium modified Type 316 stainless steel used in STARFIRE. The impurities responsible for the radioactivity levels were identified. From these radioactive impurity levels it was determined that V15Cr5Ti could meet the requirements for shallow land burial as specified by the Nuclear Regulatory Commission (10CFR61), whereas PCA would require a more restrictive disposal mode, i.e. in a geologic medium. The costs for each of these disposal modes were then estimated.

  16. Thermoelectric material development. Quarterly technical progress report, January 1, 1995--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Vandersande, J.W.; Caillat, T.

    1995-07-01

    We have found that there is a limited range of solid solutions between the skutterudite compounds CoSb{sub 3} and RuSb{sub 2}Te (about 5% on each side). For the system (RuSb{sub 2}Te){sub x}(CoSb{sub 3}){sub 1-x}, preliminary results obtained on one n-type sample on the CoSb{sub 3}-rich side show that these alloys have good thermoelectric properties and a maximum ZT of about 0.89 was obtained at about 600 C. More experiments will be started to investigate the possibility of a broader range of miscibility in this system which would allow an even further decrease in the lattice thermal conductivity, resulting in better thermoelectric properties. IrSb{sub 3} and RuSb{sub 2}Te form a complete range of solid solutions. Hot-pressed samples in this system have shown p-type conductivity. The thermoelectric properties of these p-type alloys have been measured and results have shown that their potential for thermoelectric applications is limited mainly because of the relatively low Seebeck coefficient values for p-type materials. Efforts will be directed on preparing n-type samples of the same alloys by doping with various dopants such as Ni and Pd.

  17. Progress report, Chemistry and Materials Division, 1 April - 30 June, 1981

    International Nuclear Information System (INIS)

    The work of the Division in the areas of solid state science, radiation, physical and analytical chemistry, and materials science during the quarter is described. Measurements of ion stopping power have emphasized the importance of axial symmetry and may be used to show the contribution of nuclear inelastic events to stopping processes. Enhancement of ion scattering at 180 degrees can occur even in the first few layers of a single crystal of gold implanted with heavy atoms. Agreement has been obtained between experimental and calculated rates for dechanneling of protons in gold. The rate of decomposition of HOI in aqueous solutions has been determined. The effects of radiation on dithiothreitol is being studied. Laser photochemistry work includes investigations of multiphoton dissociation and of laser-induced zirconium isotope separation. A method has been found for the preparation of oxygen gas samples for the determination of oxygen isotope ratios in water, and high-performance liquid chromatography has been applied to metals in ground water. Sputtered coatings of stainless steel on the surface of zircaloy fuel cladding reduce the oxidation rate in steam. A theoretically-based design equation for irradiation growth of pressure tubes has been developed. Studies on the effect of small strains on zircaloy-2 tubing show the need to avoid even small amounts of compressive deformation of calandria tubes

  18. Progress report, Chemistry and Materials Division: 1982 October 1 -December 31

    International Nuclear Information System (INIS)

    Solid state studies included work on the trapping vacancies of Au atoms by the backscattering-channeling method, and investigation into mixing across interfaces resulting from heavy ion bombardment. In radiation chemistry, computer simulations of nitrogen atom yield from radiolysis of N2-O2 mixtures were found to agree with experiment. Surface science research included studies of temporal oscillations in the kinetics of oxidation of carbon monoxide over the (100) face of single-crystal platinum. In analytical chemistry, research projects included the determination of thorium-230 in ores, use of a high specific activity methyl bromide tracer in commercial applications, determination of burnup in (Th,U)02 fuels using HPLC, and development of a simple and quick means to determine D20 content of water grab samples at CANDU sites using a small soft-bulb hydrometer. Materials science studies included experiments on true incubation time for stress-corrosion cracking in iodine vapour, examination of hydrogen contents of fuel cladding from bundles with failed pins, and studies of initiation of ΣnodularΣ corrosion of fuel cladding in high-temperature steam

  19. Progress report, Chemistry and Materials Division: 1982 July 1 - September 30

    International Nuclear Information System (INIS)

    During the third quarter of 1982, work in solid state studies included study of energy spectra of Auger electrons from a silicon single crystal, use of an excimer laser to anneal an aluminum crystal implanted with iron atoms, studies of defects created by helium ion irradiation of a dilute copper-indium alloy crystal, and computer simulations of ion channeling in a platinum crystal surface. Work in radiation chemistry on the enhancement of water calorimetry sensitivity continued. A surface science program to understand the temporal oscillations in the oxidation of carbon monoxide over platinum continued with the study of the interaction of oxygen with the (100) crystallographic face of platinum. Studies in analytical chemistry included a comparison of fuel burnup results using 145Nd + 146Nd and 148Nd, and a preliminary investigation into methods of reduction of U(VI) to U(IV), particularly electrolytic reduction. Materials science work continued on the fracture surfaces of Exel alloys cracked in hydrogen gas, the true incubation time for stress corrosion cracking in cesium-cadmium vapour mixtures, evidence for a previously unknown hexagonal phase of germanium, growth experiments in the DIDO reactor on swaged single-crystals, and examination of the first zirconium specimen purified by electrotransport in the CRNL equipment

  20. Ion implantation and spin quenching of superconducting materials. Technical progress report

    International Nuclear Information System (INIS)

    The work reported has focused on completing experiments on heavy dose implantations into substrates with an A-15 structure and on initiating experiments on melt spinning for forming new A-15 compounds and amorphous ribbons. The effect of ion implantation on metastable phase formation and superconducting transition temperature has been investigated. The particular alloys studied were Nb3Al/sub 1-x/B/sub x/ and Nb3Al/sub 1-x/C/sub x/. A-15 Nb3Al was used as the substrate material, and large doses of B and C (up to 23 at. %) were implanted into Al depleted surfaces. Melt spinning was used to rapidly quench V2CrAl/sub 1-x/B/sub x/ and Ti3Nb6Mo3Si4 alloys. Melt spinning had very little effect on the crystal structure of the V2CrAl/sub 1-x/B/sub x/ alloys, but a new A-15 phase was found by rapid quenching of the Ti3Nb6Mo3Si4 alloys

  1. Wide band gap materials and devices for NO{sub x}, H{sub 2} and O{sub 2} gas sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Majdeddin

    2008-01-22

    In this thesis, field effect gas sensors (Schottky diodes, MOS capacitors, and MOSFET transistors) based on wide band gap semiconductors like silicon carbide (SiC) and gallium nitride (GaN), as well as resistive gas sensors based on indium oxide (In{sub 2}O{sub 3}), have been developed for the detection of reducing gases (H{sub 2}, D{sub 2}) and oxidising gases (NO{sub x}, O{sub 2}). The development of the sensors has been performed at the Institute for Micro- and Nanoelectronic, Technical University Ilmenau in cooperation with (GE) General Electric Global Research (USA) and Umwelt-Sensor- Technik GmbH (Geschwenda). Chapter 1: serves as an introduction into the scientific fields related to this work. The theoretical fundamentals of solid-state gas sensors are provided and the relevant properties of wide band gap materials (SiC and GaN) are summarized. In chapter 2: The performance of Pt/GaN Schottky diodes with different thickness of the catalytic metal were investigated as hydrogen gas detectors. The area as well as the thickness of the Pt were varied between 250 {proportional_to} 250 {mu}m{sup 2} and 1000 {proportional_to} 1000 {mu}m{sup 2}, 8 and 40 nm, respectively. The response to hydrogen gas was investigated in dependence on the active area, the Pt thickness and the operating temperature for 1 vol.% hydrogen in synthetic air. We observed a significant increase of the sensitivity and a decrease of the response and recovery times by increasing the temperature of operation to about 350{sup o}C and by decreasing the Pt thickness down to 8 nm. Electron microscopy of the microstructure showed that the thinner platinum had a higher grain boundary density. The increase in sensitivity with decreasing Pt thickness points to the dissociation of molecular hydrogen on the surface, the diffusion of atomic hydrogen along the platinum grain boundaries and the adsorption of hydrogen at the Pt/GaN interface as a possible mechanism of sensing hydrogen by Schottky diodes. The

  2. Efficient many-body calculations for two-dimensional materials using exact limits for the screened potential: Band gaps of MoS2, h-BN, and phosphorene

    DEFF Research Database (Denmark)

    Rasmussen, Filip Anselm; Schmidt, Per Simmendefeldt; Winther, Kirsten Trøstrup;

    2016-01-01

    Calculating the quasiparticle (QP) band structure of two-dimensional (2D) materials within the GW self-energy approximation has proven to be a rather demanding computational task. The main reason is the strong q dependence of the 2D dielectric function around q = 0 that calls for a much denser...

  3. Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Cheng Wang

    2016-07-01

    Full Text Available Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst layer, gas diffusion layer, and bipolar plate. The development of high-durability processing technologies is also introduced. Finally, this review is concluded with personal perspectives on the future research directions of this area.

  4. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, July 1, 1980-September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-12

    Objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described: screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850, 950 and 1050/sup 0/C. Initiation of controlled purity helium creep-rupture testing in the intensive screening test program is discussed. In addition, the results of 1000-hour exposures at 750 and 850/sup 0/C on several experimental alloys are discussed.

  5. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, April 1, 1980-June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-14

    Objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described; this includes: screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850 and 950/sup 0/C. The initiation of air creep-rupture testing in the intensive screening test program is discussed. In addition, the status of the data management system is described.

  6. Progress in the Raman spectra analysis of covalently functionalized multiwalled carbon nanotubes: unraveling disorder in graphitic materials.

    Science.gov (United States)

    Rebelo, Susana L H; Guedes, Alexandra; Szefczyk, Monika E; Pereira, André M; Araújo, João P; Freire, Cristina

    2016-05-14

    Raman spectroscopy is highly sensitive to the morphology and electronic structures of graphitic materials, but a convenient interpretation model has been lacking for multiwalled carbon nanotubes (MWCNTs), in particular for the discrimination of spectral changes induced by covalent functionalization. The present work describes a systematic investigation of the Raman analysis of covalently functionalized MWCNTs by diazonium chemistry and oxidation methodologies, with typically different mechanisms and reaction sites. A multi-peak deconvolution system and spectral band assignment were proposed based on the chemical and structural modifications identified by X-ray photoelectron spectroscopy, thermogravimetry, X-ray diffraction, specific surface areas and the comparative analysis of the first and second order regions of the Raman spectra. Diazonium functionalization takes place mainly in the π-system of the external sidewall, while oxidation occurs on defects and leads to structure burning. This allowed us to distinguish between spectral features related to aromaticity disruptions within the sidewalls and spectral features related to changes within the inner tubes. The model was validated extending the studies to the functionalization of MWCNTs by the Bingel reaction.

  7. Presentation on the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC): A Working Model and Progress Report

    Science.gov (United States)

    Glesener, G. B.; Vican, L.

    2015-12-01

    Physical analog models and demonstrations can be effective educational tools for helping instructors teach abstract concepts in the Earth, planetary, and space sciences. Reducing the learning challenges for students using physical analog models and demonstrations, however, can often increase instructors' workload and budget because the cost and time needed to produce and maintain such curriculum materials is substantial. First, this presentation describes a working model for the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC) to support instructors' use of physical analog models and demonstrations in the science classroom. The working model is based on a combination of instructional resource models developed by the Association of College & Research Libraries and by the Physics Instructional Resource Association. The MEDL-CMC aims to make the curriculum materials available for all science courses and outreach programs within the institution where the MEDL-CMC resides. The sustainability and value of the MEDL-CMC comes from its ability to provide and maintain a variety of physical analog models and demonstrations in a wide range of science disciplines. Second, the presentation then reports on the development, progress, and future of the MEDL-CMC at the University of California Los Angeles (UCLA). Development of the UCLA MEDL-CMC was funded by a grant from UCLA's Office of Instructional Development and is supported by the Department of Earth, Planetary, and Space Sciences. Other UCLA science departments have recently shown interest in the UCLA MEDL-CMC services, and therefore, preparations are currently underway to increase our capacity for providing interdepartmental service. The presentation concludes with recommendations and suggestions for other institutions that wish to start their own MEDL-CMC in order to increase educational effectiveness and decrease instructor workload. We welcome an interuniversity collaboration to

  8. First analysis of the 1-v″ progression of the Ångström (B1Σ+-A1Π) band system in the rare 13C17O isotopologue.

    Science.gov (United States)

    Hakalla, Rafał; Zachwieja, Mirosław; Szajna, Wojciech

    2013-11-27

    The 1-v″ progression of the Ångström band system, so far unobserved in the rare (13)C(17)O isotopologue, was obtained under high resolution as an emission spectrum using a high accuracy dispersive optical spectroscopy. In the studied region 22,700-24,500 cm(-1), 146 spectral lines were observed, among which 118 were interpreted as belonging to the 1-0 and 1-1 bands of B-A system, and the next 28 were interpreted as extra lines belonging to the 1-1 band of B(1)Σ(+)-e(3)Σ(-) intercombination system, also unobserved in the (13)C(17)O molecule so far. All those lines were precisely measured with an estimated accuracy better than 0.0025 cm(-1), and rotationally analyzed. As a result the following in the (13)C(17)O molecule were calculated for the first time: the merged rotational constants B1 = 1.790227(23) cm(-1), D1 = 6.233(47) × 10(-6) cm(-1), and ΔG1/2 = 2010.9622 (69) cm(-1) and the equilibrium constants, ωe = 2076.04(57) cm(-1), ωexe = 32.54(28) cm(-1), Be = 1.824678(15) cm(-1), αe = 2.2967(24) × 10(-2) cm(-1), De = 5.226(25) × 10(-6) cm(-1), and βe = 6.71(48) × 10(-7) cm(-1) for the B(1)Σ(+) Rydberg state, as well as the individual rotational constant B0 = 1.50485(78) cm(-1), and the equilibrium constants ωe = 1463.340(21) cm(-1), Be = 1.49902(12) cm(-1), αe = 1.7782(49) × 10(-2) cm(-1), De = 7.36(56) × 10(-6) cm(-1) for the A(1)Π state, and σe = 21,854.015(51) cm(-1), RKR turning points, Franck-Condon factors (FCF), relative intensities, and r centroids for the Ångström band system. With the help of the strong and vast A(1)Π (v = 0) ∼ e(3)Σ(-) (v = 1) interaction, the experimental parameters of the e(3)Σ(-) (v = 1) perturbing state were established in the (13)C(17)O molecule for the first time. PMID:24138166

  9. A Comparison of the Progression and Recurrence Risk Index in Non-Muscle-Invasive Bladder Tumors Detected by Narrow-Band Imaging Versus White Light Cystoscopy, Based on the EORTC Scoring System

    Directory of Open Access Journals (Sweden)

    Shadpour

    2016-01-01

    Full Text Available Background Transitional cell carcinoma of the bladder, the second most common urologic malignancy, is amenable to early diagnosis. This study presents the potential prognostic benefit for a less invasive modification to the standard endoscopic approach. Objectives To evaluate the risk index for the progression and recurrence of additional tumors detected with narrow-band imaging (NBI cystoscopy compared to standard white light imaging (WLI cystoscopy in non-muscle-invasive bladder cancer (NMIBC, based on the European organization for research and treatment of cancer (EORTC scoring system. Patients and Methods Patients with NMIBC, who were scheduled for resection between May 2012 and May 2013, were studied and mapped under NBI and WLI cystoscopy by independent surgeons prior to resection. Detection rates and tumor characteristics, including EORTC progression and the recurrence risk index, were compared. Results Fifty patients, aged 63.86 ± 10.05 years, were enrolled. The overall detection rate was 98.9% for NBI vs. 89.4% for WLI (P = 0.001, and the false-positive rates were 9.6% and 5.8%, respectively (P = 0.051. Ten tumors were detected by NBI alone, including four grade I tumors, four grade III tumors, and two carcinomas in situ. The tumor progression index was not significantly reduced with NBI compared to WLI (P > 0.05; however, the recurrence index was significantly lower in the NBI group (P < 0.05. Conclusions NBI cystoscopy improved the detection rate. Although false positives were more common with NBI, this was not statistically significant. NBI found additional aggressive tumors, which underscores the impact of detection in EORTC recurrence risk scoring.

  10. Screened coulomb hybrid DFT investigation of band gap and optical absorption predictions of CuVO3, CuNbO3 and Cu 5Ta11O30 materials

    KAUST Repository

    Harb, Moussab

    2014-01-01

    We present a joint theoretical and experimental investigation of the optoelectronic properties of CuVO3, CuNbO3 and Cu 5Ta11O30 materials for potential photocatalytic and solar cell applications. In addition to the experimental results obtained by powder X-ray diffraction and UV-Vis spectroscopy of the materials synthesized under flowing N2 gas at atmospheric pressure via solid-state reactions, the electronic structure and the UV-Vis optical absorption coefficient of these compounds are predicted with high accuracy using advanced first-principles quantum methods based on DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 exchange-correlation formalism. The calculated density of states are found to be in agreement with the UV-Vis diffuse reflectance spectra, predicting a small indirect band gap of 1.4 eV for CuVO3, a direct band gap of 2.6 eV for CuNbO3, and an indirect (direct) band gap of 2.1 (2.6) eV for Cu5Ta 11O30. It is confirmed that the Cu(i)-based multi-metal oxides possess a strong contribution of filled Cu(i) states in the valence band and of empty d0 metal states in the conduction band. Interestingly, CuVO3 with its predicted small indirect band gap of 1.4 eV shows the highest absorption coefficient in the visible range with a broad absorption edge extending to 886 nm. This novel result offers a great opportunity for this material to be an excellent candidate for solar cell applications. © the Partner Organisations 2014.

  11. Evaluation of caries progression in dentin treated by fluoride-containing materials using an in-air micro-PIGE and micro-PIXE measurement system

    International Nuclear Information System (INIS)

    It is well-known that fluorine (F) is involved in the progression of caries. The evaluation of caries progression has conventionally been based on the change in mineral content using transverse microradiography (TMR). The purpose of this study was to evaluate the progression of dentinal caries by the change in calcium (Ca) content using Particle-Induced Gamma-ray Emission/Particle-Induced X-ray Emission (PIGE/PIXE) techniques at the Wakasa Wan Energy Research Center. We also assessed the relationship between caries progression rate and the concentration of F penetration into dentin from dental fluoride-containing materials (FCMs). Dentin sections of six extracted human teeth were prepared to obtain various amounts of F uptake using three types of FCMs. F and Ca distribution of specimens were obtained using PIGE/PIXE techniques. After evaluation, the specimens were immersed in 10 ml of demineralizing solution (pH 4.5) to simulate caries attack. To estimate caries progression rates, the same portions of the specimens were evaluated after caries attack treatment using PIGE/PIXE. A negative correlation between the F uptake in dentin and the rate of caries progression was observed. Therefore, caries progression in dentin was reduced by increasing the amount of F uptake from FCMs. This demonstrates that PIGE/PIXE techniques are valuable for estimating caries progression rates

  12. Evaluation of caries progression in dentin treated by fluoride-containing materials using an in-air micro-PIGE and micro-PIXE measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H., E-mail: yhiroko@dent.osaka-u.ac.jp [Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamada-Oka, Suita 565-0871 (Japan); Iwami, Y.; Yagi, K.; Hayashi, M. [Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamada-Oka, Suita 565-0871 (Japan); Komatsu, H.; Okuyama, K.; Matsuda, Y. [Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Yasuda, K. [The Wakasa Wan Energy Research Center, 64-52-1 Nagatani, Tsuruga 914-0192 (Japan)

    2015-04-01

    It is well-known that fluorine (F) is involved in the progression of caries. The evaluation of caries progression has conventionally been based on the change in mineral content using transverse microradiography (TMR). The purpose of this study was to evaluate the progression of dentinal caries by the change in calcium (Ca) content using Particle-Induced Gamma-ray Emission/Particle-Induced X-ray Emission (PIGE/PIXE) techniques at the Wakasa Wan Energy Research Center. We also assessed the relationship between caries progression rate and the concentration of F penetration into dentin from dental fluoride-containing materials (FCMs). Dentin sections of six extracted human teeth were prepared to obtain various amounts of F uptake using three types of FCMs. F and Ca distribution of specimens were obtained using PIGE/PIXE techniques. After evaluation, the specimens were immersed in 10 ml of demineralizing solution (pH 4.5) to simulate caries attack. To estimate caries progression rates, the same portions of the specimens were evaluated after caries attack treatment using PIGE/PIXE. A negative correlation between the F uptake in dentin and the rate of caries progression was observed. Therefore, caries progression in dentin was reduced by increasing the amount of F uptake from FCMs. This demonstrates that PIGE/PIXE techniques are valuable for estimating caries progression rates.

  13. ANALYSIS AND DESIGN OF TWO DIMENSIONAL LATTICE MATERIALS WITH BAND-GAP CHARACTERISTICS%二维格栅材料带隙特性分析与设计

    Institute of Scientific and Technical Information of China (English)

    黄毓; 刘书田

    2011-01-01

    Periodic materials or structures own the capability of attenuating wave propagation over certain frequency bands, which is called band-gap characteristics, and the materials can be reasonably designed to adjust the location and width of band gaps. With the great potential applications such as filters, wave guides and sound or vibration isolation, the effect of the configuration in microstructure on the band-gap characteristics is investigated. First, the band-gap behaviors of elastic wave and the attenuation characteristics in localization in seven 2D periodic lattice topologies, namely triangular honeycomb, square honeycomb, ground honeycomb,hexagonal honeycomb, auxetic honeycomb, Kagome honeycomb and diamond honeycomb, are analyzed and compared. Objective function to measure low and wide band-gap character is proposed, and the optimal bandgap material is then selected. Furthermore, the laws of geometry configuration parameters affecting on the band-gap characteristics are obtained and numerically demonstrated. The techniques developed in this work can be applied in design periodic band-gap materials by adjusting geometry configurations in the microstructure.%周期性材料或结构常表现出阻断特定频段的波传播的特异性质(带隙性质),通过合理设计可以调整带隙的位置和带宽等,带隙材料在滤波、导波、隔音、隔振等方面有巨大的应用潜力.据此背景,研究了材料微结构构型对带隙性质的影响.分析和比较了三角形、米字形、四边形、六边形、反六边形、Kagome形和钻石形等7种典型拓扑构形格栅材料的带隙性质与弹性波在其中的局部衰减特性,提出了可表征特定带隙性质的目标函数,从而对不同构型的材料进行选优;进一步得到并数值验证了材料微结构中几何参数对带隙性质的影响规律,为通过改变构型几何参数设计具有特定性质的带隙材料提供参考.

  14. Evaluation of dry-solids-blend material source for grouts containing 106-AN waste: September 1990 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Gilliam, T.M.; Osborne, S.C.; Francis, C.L.; Scott, T.C.

    1993-09-01

    Stabilization/solidification (S/S) is the most widely used technology for the treatment and ultimate disposal of both radioactive and chemically hazardous wastes. Such technology is being utilized in a Grout Treatment Facility (GTF) by the Westinghouse Hanford Company (WHC) for the disposal of various wastes, including 106-AN wastes, located on the Hanford Reservation. The WHC personnel have developed a grout formula for 106-AN disposal that is designed to meet stringent performance requirements. This formula consists of a dry-solids blend containing 40 wt % limestone, 28 wt % granulated blast furnace slag (BFS), 28 wt % ASTM Class F fly ash, and 4 wt % Type I-II-LA Portland cement. The blend is mixed with 106-AN waste at a ratio of 9 lb of dry-solids blend per gallon of waste. This report documents progress made to date on efforts at Oak Ridge National Laboratory (ORNL) in support of WHC`s Grout Technology Program to assess the effects of the source of the dry-solids-blend materials on the resulting grout formula.

  15. An open labeled, comparative clinical study on efficacy and tolerability of oral minipulse of steroid (OMP alone, OMP with PUVA and broad / narrow band UVB phototherapy in progressive vitiligo

    Directory of Open Access Journals (Sweden)

    Rath Namita

    2008-01-01

    Full Text Available Background: Several modalities of treatment have been tried in vitiligo with varied results; however, Indian data on comparative studies of two or more therapies are limited. Aims: We compared different phototherapy methods with an oral steroid as an adjunct to determine the method with the best tolerability and efficacy. Methods: Eighty-six patients with progressive vitiligo were randomly assigned to different study groups according to a continuous selection method over a period of one year. Group 1 was given OMP + PUVA, group 2 OMP + UVB (NB, group 3 OMP + UVB (BB and group 4 was given OMP alone. Each patient was followed up for six months and then released from treatment. Clinical evaluation was made at the end of three and six months. Results: In group 1 (OMP + PUVA, marked improvement was seen in 18.51% while moderate improvement was seen in 66.66% of the patients. Marked improvement was seen in 37.03% in group 2 (OMP + NB-UVB while 44.44% had moderate improvement. In group 3 (OMP + BB UVB, 8.33% showed marked improvement while moderate improvement was seen in 25% of the patients. Marked and moderate improvement was seen in 5 and 10% of group 4 (OMP patients, respectively. Conclusions: Our study compared four treatment modalities in vitiligo patients, out of which oral minipulse of steroids (OMP only had an adjunct value and was not very effective by itself. Narrow band UVB has a definite edge over broad band UVB and should be preferred when both options are available. NB-UVB and PUVA showed comparable efficacy.

  16. Development of small-bore, high-current-density railgun as testbed for study of plasma-materials interaction. Progress report for October 16, 2000 - May 13, 2003

    International Nuclear Information System (INIS)

    The present document is a final technical report summarizing the progress made during 10/16/2000 - 05/13/2003 toward the development of a small-bore railgun with transaugmentation as a testbed for investigating plasma-materials interaction

  17. Materials testing and requirement for the ERDA nuclear-powered artificial heart. Technical progress report, July 15, 1975--May 30, 1976. [BIOMER and AVCOTHANE

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, J. D.; Hufferd, W. L.; Lyman, D. J.

    1976-01-01

    The two materials currently being used for the artificial heart fabrication are BIOMER and AVCOTHANE. BIOMER is a polyether urethane polymer. AVCOTHANE is a proprietary polyurethane/polydimethylsiloxane polymer blend. Research progress on the chemical degradation, mechanical strength, and blood compatibility is reported. (TFD)

  18. Microstrip microwave band gap structures

    Indian Academy of Sciences (India)

    V Subramanian

    2008-04-01

    Microwave band gap structures exhibit certain stop band characteristics based on the periodicity, impedance contrast and effective refractive index contrast. These structures though formed in one-, two- and three-dimensional periodicity, are huge in size. In this paper, microstrip-based microwave band gap structures are formed by removing the substrate material in a periodic manner. This paper also demonstrates that these structures can serve as a non-destructive characterization tool for materials, a duplexor and frequency selective coupler. The paper presents both experimental results and theoretical simulation based on a commercially available finite element methodology for comparison.

  19. Research Progress of Carbon Dioxide Capture Materials%二氧化碳捕获材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    付新

    2011-01-01

    The research progress of emission reduce and capture of carbon dioxide at home and abroad were introduced in this paper,and carbon dioxide capture materials were focused on,which included some traditional adsorption materials, such as the hydramine class adsorbent, the ionic liquids adsorption material, the metal compound material,the ceramic material,zeolite and molecular sieve material,carbon-based adsorption material and silica gel material,as well as a series of novel capture materials such as the composite adsorption material and the anion selective adsorption material. The development trends of carbon dioxide capture materials were put forward.%简要阐述了近年来二氧化碳的减排、捕获等最新技术的研究进展,着重介绍了二氧化碳捕获材料的研究状况,如醇胺类吸附剂、离子液体吸附材料、金属化合物材料、陶瓷材料、沸石分子筛材料、碳基吸附材料、硅胶材料等传统吸附材料及复合型材料、负离子选择性吸附材料等新型捕获材料.并对二氧化碳捕获材料的发展趋势进行了展望.

  20. Familial band-shaped keratopathy.

    Science.gov (United States)

    Ticho, U; Lahav, M; Ivry, M

    1979-01-01

    A brother and sister out of a consanguinous family of four siblings are presented as prototypes of primary band-shaped keratopathy. The disease manifested sever progressive changes of secondary nature over two years of follow-up. Histology and treatment are described.

  1. 平板式SOFC封接材料的研究进展%RESEARCH PROGRESS OF SEALING MATERIALS FOR PLANAR SOFC

    Institute of Scientific and Technical Information of China (English)

    程丹; 罗凌虹; 吴也凡; 程亮; 石纪军

    2012-01-01

    The recent progress of sealing materials used for planar solid oxide fuel cell(pSOFC) was reviewed in this paper.The basic requirements of sealing materials and the sealing technique for SOFC were pointed.At last the glass sealing materials were presented in detail.%本文对平板式SOFC封接材料的最新研究进展进行了介绍:封接材料的基本要求和SOFC的封接方式。并对玻璃、玻璃-陶瓷封接材料进行了详细的阐述。

  2. Research progress in anode materials for Li-ion battery%锂离子电池负极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    武明昊; 陈剑; 王崇; 衣宝廉

    2011-01-01

    综述了近年来锂离子电池负极材料的研究进展,包括碳材料、过渡金属氧化物,锡基和硅基材料等,重点评述了锡基和硅基材料的研究进展,并对锂离子电池负极材料的发展趋势进行了展望.%Research progress in anode materials for Li-ion battery in recent years, including carbon, transition metal oxides, tin based composites and silicon based composites was reviewed. The research progress in tin based and silicon based anode materials was commented emphatically,the development tendency of Li-ion battery anode materials was prospected.

  3. Research Progress on Buffer Layer Materials of CIGS Thin Film Solar Cell%CIGS薄膜太阳能电池缓冲层材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    王卫兵; 刘平; 李伟; 马凤仓; 刘新宽; 陈小红

    2012-01-01

    CIGS薄膜太阳能电池的缓冲层为低带隙CIGS吸收层与高带隙ZnO窗口层之间形成过渡,减少两者带隙的晶格失配和带隙失调,并可防止溅射ZnO窗口层时给CIGS吸收层带来损害等,对提高CIGS薄膜太阳能电池效率起了重要作用.介绍了CIGS薄膜太阳能电池缓冲层材料的分类和制备工艺,主要阐述了CdS、ZnS及In2S3薄膜缓冲层材料及化学水浴法、原子层化学气相沉积法、金属化合物化学气相沉积法等制备工艺的研究现状,最后指出CIGS太阳能电池缓冲层在制备工艺、环境保护及大规模工业化生产中遇到的问题,并展望了其发展方向.%The buffer layers of CTGS thin film solar cells can form transition layers between low band gap CIGS absorber layers and high band gap of ZnO window layers, which reduces the lattice matching and band gap difference, and prevents damage of CIGS absorber layer from sputtering ZnO window layer, and therefore plays an important role in improving efficiency of CIGS thin film solar cells. Classification and preparation technology of CIGS thim film solar cells material are discussed, including the research progress of CdS,ZnS and In2S3 thin film buffer layer materials, and chemical bath deposition (CBD), atomic layer chemical vapor deposition (ALCVD), metal organic chemical vapor deposition (MOCVD) and other preparation technologies. The problems and development directions of buffer layer materials of CIGS thin film solar cells in preparation process, environment protection and large-scale industrial production are finally prospected.

  4. Gas-Cooled Reactor Programs annual progress report for period ending December 31, 1973. [HTGR fuel reprocessing, fuel fabrication, fuel irradiation, core materials, and fission product distribution; GCFR fuel irradiation and steam generator modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Coobs, J.H.; Lotts, A.L.

    1976-04-01

    Progress is summarized in studies relating to HTGR fuel reprocessing, refabrication, and recycle; HTGR fuel materials development and performance testing; HTGR PCRV development; HTGR materials investigations; HTGR fuel chemistry; HTGR safety studies; and GCFR irradiation experiments and steam generator modeling.

  5. Simple Calculation of Power Conversion Efficiency of PC61BM and PC71 BM Based Organic Solar Cells--Good Agreement with Experiments in Donor Materials with Different Band Gap Energies.

    Science.gov (United States)

    Otsura, Takanori; Nakatsuka, Emi; Nagase, Takashi; Kobayashi, Takashi; Naito, Hiroyoshi

    2016-04-01

    The power conversion efficiencies (PCEs) as a function of band gap energies and the lowest unoccupied molecular orbital (LUMO) levels of donor materials are studied in bulk-heterojunction organic solar cells (OSCs) fabricated from donor materials and fullerene acceptors. The PCEs of [6,6]-pheynl-C61-butyric acid methyl ester (PC61BM) and [6,6]-pheynl-C71-butyric acid methyl ester (PC71 BM) based OSCs blended with donor materials under the Air Mass 1.5 (AM1.5) spectrum are calculated. In the calculation, the short circuit current densities are determined by band gap energies of donor materials and the open circuit voltages are derived from the difference between the highest occupied molecular orbital (HOMO) levels of donor materials and LUMO levels of PC61BM and PC71 BM. The calculation is in good agreement with the experiments. The PCEs under a fluorescent lamp are also calculated. The calculated PCEs of PC71 BM based OSCs under a fluorescent lamp are higher than those under the AM1.5 spectrum by a factor of 2. The PCEs of thieno [3,4-b] thiophene and benzodithiophene (PTB7):PC71BM based OSCs are studied under the AM1.5 spectrum and a fluorescent lamp spectrum and are consistent with the calculation. PMID:27451630

  6. Tm3+/Yb3+ co-doped tellurite glass with silver nanoparticles for 1.85 μm band laser material

    Science.gov (United States)

    Huang, Bo; Zhou, Yaxun; Cheng, Pan; Zhou, Zizhong; Li, Jun; Jin, Wei

    2016-10-01

    Tm3+/Yb3+ co-doped tellurite glasses with different silver nanoparticles (Ag NPs) concentrations were prepared using the conventional melt-quenching technique and characterized by the UV/Vis/NIR absorption spectra, 1.85 μm band fluorescence emission spectra, transmission electron microscopy (TEM) images, differential scanning calorimeter (DSC) curves and X-ray diffraction (XRD) patterns to investigate the effects of Ag NPs on the 1.85 μm band spectroscopic properties of Tm3+ ions, thermal stability and structural nature of glass hosts. Under the excitation of 980 nm laser diode (LD), the 1.85 μm band fluorescence emission of Tm3+ ions enhances significantly in the presence of Ag NPs with average diameter of ∼8 nm and local surface Plasmon resonance (LSPR) band of ∼590 nm, which is mainly attributed to the increased local electric field induced by Ag NPs at the proximity of doped rare-earth ions on the basis of energy transfer from Yb3+ to Tm3+ ions. An improvement by about 110% of fluorescence intensity is observed in the Tm3+/Yb3+ co-doped tellurite glass containing 0.5 mol% amount of AgNO3 while the prepared glass samples possess good thermal stability and amorphous structural nature. Meanwhile, the Judd-Ofelt intensity parameters Ωt (t = 2,4,6), spontaneous radiative transition probabilities, fluorescence branching ratios and radiative lifetimes of relevant excited levels of Tm3+ ions were determined based on the Judd-Ofelt theory to reveal the enhanced effects of Ag NPs on the 1.85 μm band spectroscopic properties, and the energy transfer micro-parameters and phonon contribution ratios were calculated based on the non-resonant energy transfer theory to elucidate the energy transfer mechanism between Yb3+ and Tm3+ ions. The present results indicate that the prepared Tm3+/Yb3+ co-doped tellurite glass with an appropriate amount of Ag NPs is a promising lasing media applied for 1.85 μm band solid-state lasers and amplifiers.

  7. Research Progress of High-Barrier Packaging Materials%高阻隔包装材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘丹

    2014-01-01

    The preparation technology, barrier properties and research progress of high-barrier packaging materials have been concluded covering inorganic strengthened high barrier materials such as vapor deposited barrier materials and inorganic filler blend materials, biodegradable materials such as MFC composite materials, multilayer composite materials and smart barrier materials. The development of high-barrier packaging material researches should be conducted towards the direction of optimal properties, non-toxic, non-pollution, green for environment, market orientation and intelligence.%综述了蒸镀阻隔材料及无机物充填共混阻隔材料等无机物增强高阻隔材料、MFC 涂布材料及MFC 复合材料等可生物降解阻隔材料、多层复合材料以及智能阻隔材料的制备工艺、阻隔性能及其在国内外的研究进展,并指出今后高阻隔材料的研究应朝着性能最优化、无毒无污染、绿色环保、适应市场需求、智能化等方向发展。

  8. Narrow-Band Microwave Filters

    Directory of Open Access Journals (Sweden)

    A.V. Strizhachenko

    2010-01-01

    Full Text Available Original design of the narrow-band compact filters based on the high-quality waveguide-dielectric resonator with anisotropic materials has been presented in this work. Designed filters satisfy the contradictory requirements: they provide the narrow frequency band (0.05 ÷ 0.1 % of the main frequency f0 and the low initial losses α0 ≤ 1 dB.

  9. 近年来辐射固化材料的研究进展%RESEARCH PROGRESS OF RADIATION CURING MATERIALS

    Institute of Scientific and Technical Information of China (English)

    杨永源

    2001-01-01

    综述了光化学、光自由基聚合、光引发剂UV固化、UV固化剂、电沉积光敏抗蚀剂和涂料、UV水基和粉末涂料及UV固化纳米复合材料的研究进展。%In this paper,research progress of radiation curing materials was reviewed.It included photochemistry,photo radical polymerization,photo initiator,UV curing agent,light sensitive resistant and photo sensitive coat in electrodeposition,UV curing aqueous or powdered coating and nanometer composite materials.

  10. Research progress in modification of key materials for lithium-sulfur battery%锂硫电池关键材料改性的研究进展

    Institute of Scientific and Technical Information of China (English)

    李红; 徐强; 余劲鹏; 桑林

    2012-01-01

    综述了锂硫电池关键材料改性研究进展,重点对硫正极、电解质和锂负极等3个方面的改性进行了介绍,展望了锂硫电池的研究重点.%Research progress in modification of key materials for lithium-sulfur battery was introduced. The modification of cathode materials,electrolyte and lithium anode were emphatically reviewed. The research focus of lithium-sulfur battery was prospected.

  11. A rheometer for measuring the material moduli for granular solids. Quarterly progress report, March 1, 1993--May 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, K.R.

    1996-02-01

    This report describes the design of an orthogonal rheometer for the measuring of properties of granular materials such as coal. A section is presented on constitutive modeling of granular materials based on continuum theory.

  12. Low band gap polymers for organic photovoltaics

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Krebs, Frederik C

    2007-01-01

    Low band gap polymer materials and their application in organic photovoltaics (OPV) are reviewed. We detail the synthetic approaches to low band gap polymer materials starting from the early methodologies employing quinoid homopolymer structures to the current state of the art that relies...

  13. Semiconductors bonds and bands

    CERN Document Server

    Ferry, David K

    2013-01-01

    As we settle into this second decade of the twenty-first century, it is evident that the advances in micro-electronics have truly revolutionized our day-to-day lifestyle. The technology is built upon semiconductors, materials in which the band gap has been engineered for special values suitable to the particular application. This book, written specifically for a one semester course for graduate students, provides a thorough understanding of the key solid state physics of semiconductors. It describes how quantum mechanics gives semiconductors unique properties that enabled the micro-electronics revolution, and sustain the ever-growing importance of this revolution.

  14. Spin-flip scattering and band structure mismatch effect on transport of pure spin across ferromagnetic semimetal/metal material interfaces

    Science.gov (United States)

    Pasanai, K.

    2016-03-01

    The tunneling conductance spectra of a ferromagnetic semimetal/metal junction, where there were electrons and holes with the same spin directions as the essential conducting particle, was theoretically studied based on a scattering approach in a ballistic regime. The main area of interest was to perform a high spin polarization by considering the effect of the interfacial scattering at the interface that was composed of normal and spin-flip scattering, the particle effective mass mismatch on the reflection and transmission probabilities, and spin polarization of conductance. It was found that the spin polarization of conductance decreased with increasing spin-flip scattering. Interestingly, the normal scattering can cause the spin polarization of the conductance to reach a maximum value in the presence of both kinds of scattering. When the particle effective mass mismatch was considered, the spin polarization of conductance was large when the electron effective mass in the valence band was smaller than that in the conduction band. However, in this calculation, the results of a ferromagnetic semimetal/metal junction behaved similarly to those of a ferromagnetic metal/metal junction.

  15. Progress Report {number_sign}1 on the materials identification, characterization and evaluation activity: Acquisition of materials data from the Exploratory Studies Facility

    Energy Technology Data Exchange (ETDEWEB)

    Meike, A., LLNL

    1998-02-01

    This paper reports on the initial work within the Materials Identification, Characterization and Evaluation Sub-activity Integration Activity within the Introduced Materials Task (IMT) (WBS 1.2.3.12.5). The goals of this activity are twofold.: (1) to identify and characterize types and usage of materials that are most likely to be introduced into a potential High Level Radioactive Waste (HLW) repository at Yucca Mountain, Nevada, as a result of its construction and operation and (2) to provide tools for the Integration Activity to evaluate the chemical impact on the repository based on information gathered from sources external and internal to the Introduced Materials Task-by the Literature Survey Sub-activity (Integration Activity, IMT). Based on this information and assessment, the Integration Activity activates relevant activities within the Introduced Materials Task and provides information to other Tasks within the Yucca Mountain Project.

  16. Hazardous materials in aquatic environments of the Mississippi River Basin. Quarterly progress report, July 1, 1995--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    This report is the quarterly progress report for July through September 1995 for work done by Tulane and Xavier Universities under DOE contract number DE-FG01-93-EW53023. Accomplishments for various tasks including administrative activities, collaborative cluster projects, education projects, initiation projects, coordinated instrumentation facility, and an investigators` retreat are detailed in the report.

  17. RESEARCH PROGRESS IN INTELLIGENT COMPOSITE MATERIALS%智能复合材料研究进展

    Institute of Scientific and Technical Information of China (English)

    林超; 陈凤; 袁莉; 梁国正

    2012-01-01

    智能复合材料作为一种新型高技术材料,兼具结构与功能双重特性.根据近几年来智能复合材料的研究现状,本文介绍了几种主要的智能复合材料:形状记忆复合材料、自修复智能复合材料、压电智能复合材料、电/磁流变智能复合材料及纤维素智能复合材料,简述了智能复合材料领域当前研究热点,介绍了该领域中存在的一些问题,展望了智能复合材料的发展前景.%The intelligent composite materials have been regarded as novel high-tech materials with structural and functional characteristics. Several intelligent composite materials were introduced in this paper based on the studies in recent years, such as shape memory material, self-healing material, piezoelectric material, electrorheo logical/magnetorheological material, and cellulose material. The paper briefly introduces the hot topics of the current research involved in intelligent composite material, it also points out the existing problems in the field and provides some perspectives and insights about the development of the intelligent composite materials.

  18. Desarrollo de técnicas de caracterización para materiales de banda intermedia : Development of characterization techniques for intermediate band materials

    OpenAIRE

    Cánovas Díaz, Enrique

    2009-01-01

    El término material de banda intermedia (IB) hace referencia a un material semiconductor que, difiriendo de los semiconductores convencionales definidos por una única banda prohibida, posee una banda electrónica extra localizada entre la banda de valencia (VB) y la banda de conducción (CB). De esta manera, este material estaría definido por dos bandas prohibidas, posibilitando que fenómenos de generación y recombinación de portadores se produzcan no solo entre la VB y la CB sino también entre...

  19. Fossil Energy Advanced Research and Technology Development Materials Program. Semiannual progress report for the period ending September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Cole, N.C.; Judkins, R.R. [comps.

    1992-12-01

    Objective of this materials program is to conduct R and D on materials for fossil energy applications with focus on longer-term and generic needs of the various fossil fuel technologies. The projects are organized according to materials research areas: (1) ceramics, (2) new alloys: iron aluminides, advanced austenitics and chromium niobium alloys, and (3) technology development and transfer. Separate abstracts have been prepared.

  20. LCR分流电路下压电声子晶体智能材料的带隙∗%Band gaps of the phononic piezo electric smart materials with LCR shunting circuits

    Institute of Scientific and Technical Information of China (English)

    唐一璠; 林书玉

    2016-01-01

    Environmental forces can produce undesired vibrations in mechanical structures that can limit the precision of mechanical equipment and cause mechanical failure. Piezoelectric-shunt damping is an attractive technique for controlling the vibrating structures, which is reliable, economical and light-weight. Phononic crystal is an internal component whose elastic constant, density and sound velocity change periodically. When the elastic wave passes through a phononic crystal, special dispersion curve is formed due to the interaction of periodic arrangement materials. In order to study the electromagnetic oscillation band gap of the piezoelectric phononic crystal with LCR shunt network at torsional and flexural vibration, we propose a new phononic piezoelectric beam, which is composed of aluminum and epoxy resin. When the piezoelectric patch is strained, the electrical energy is dissipated as current flows through an external LCR shunting circuit. By combining the piezoelectric effect with the mechanical vibration of the smart material, the equivalent additional stress of piezoelectric patches is deduced. Moreover, coupling the energy band theory of phononic crystal with the effect of electromagnetic oscillation, we calculate the band gap characteristics of torsional and flexural vibration of intelligent material. Using the transfer matrix method and Bloch theorem for periodic boundary conditions, the band gap of the phononic beam can be calculated. With the increase of resistance, the amplitude attenuation of the band gap decreases. However, it can expand the frequency range. The inherent frequency of the electromagnetic oscillation is 1/[2π√L(C+CP )]. The sum of capacitance and inherent capacitance is the total capacitance of the shunting circuit. Therefore, the frequency of the electromagnetic oscillation decreases with the increases of the capacitance and inductance. The amplitude attenuation of the band gap increases with the increase of the inductance and

  1. Research progress of nanometer materials in ionic liquid microemulsion%离子液体微乳液合成纳米材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    周刚; 罗志刚

    2013-01-01

    Ionic liquid microemulsion is a new method for the preparation of nanometer materials. Re-search status of ionic liquid microemulsion and recent progress of the preparation of nanometer materials through ionic liquid microemulsion method were reviewed in this paper. The applications of ionic liquid mi-croemulsion in the preparation of nanometer materials were discussed.%离子液体微乳液法是制备纳米材料的新型方法,近年来得到了很快的发展。本文阐述了离子液体微乳液的研究现状以及采用离子液体微乳液法合成纳米材料的最新研究进展,并对离子液体微乳液在合成淀粉纳米材料的应用进行了探讨。

  2. 纳米复合包装材料的研究与应用进展%Study and Application Progress of Nano-composite Packaging Materials

    Institute of Scientific and Technical Information of China (English)

    孙新; 黄俊彦; 吴双岭; 孙成伦

    2012-01-01

    综述了纳米复合包装材料的特点及其在食品包装领域的应用,介绍了纳米复合包装材料特有的保鲜性、抗菌性、高阻隔性等性能的研究和应用现状,并对纳米复合包装材料的安全性进行了分析评价.%The characteristics of nano-composite packaging materials and its application in food packaging fields were reviewed; the research progress of performances of nano-composite packaging materials, such as preservation performance, antibiotic property and high barrier property, and its application situation were introduced. The security of nano-composite packaging materials were analyzed and evaluated.

  3. Diet after gastric banding

    Science.gov (United States)

    Gastric banding surgery - your diet; Obesity - diet after banding; Weight loss - diet after banding ... about any problems you are having with your diet, or about other issues related to your surgery ...

  4. Iliotibial band syndrome - aftercare

    Science.gov (United States)

    IT band syndrome - aftercare; Iliotibial band friction syndrome - aftercare ... If you have iliotibial band syndrome you may notice: Mild pain on the outside of your knee when you begin to exercise, which goes ...

  5. Research progress in cathode materials for lithium-air battery%锂空气电池正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    娄永兵; 刘艳; 朱林

    2012-01-01

    综述了目前国内外锂空气电池研究领域的进展,尤其是正极材料的研究进展;分析了目前研究的局限和问题的集中所在,如过电位、循环稳定性和安全性等;展望了锂空气电池的发展方向及应用趋势.%The progress in lithium-air battery research was reviewed,specifically the progress in cathode materials. The current research limitations and existing problems were discussed,such as over potential, cycle stability and safety, the development direction and application trend were forecasted.

  6. Progress of studies on heavy metal chelating composite materials%重金属螯合复合材料研究进展

    Institute of Scientific and Technical Information of China (English)

    荆秀艳; 赵文华; 王涵; 陈龙; 张焕; 刘转年

    2014-01-01

    This paper reviewed the toxicity,source and control methods of heavy metal ions,the progress of heavy metal chelator and composite materials were also introduced. The progress of heavy metal chelating composite materials from macromolecule resin,silicon particles,biomass materials, nanoparticles and mesoporous materials as matrics were analyzed and discussed. The future research directions were proposed as the following: the selection of matrix materials should focus on the sources,price and properties of materials,biomass materials,mesoporous materials and nano-porous materials should be selected with priority; new efficient chelating functional groups should be explored and developed;and the preparation and use of composite material must be pollution free and compatible with environment.%重金属离子由于其毒性和不可降解性,严重威胁着人们的生存环境和身体健康,一直是环境污染治理领域研究的重点和难点。本文介绍了重金属离子的危害和来源及处理方法,综述了重金属螯合剂和重金属螯合复合材料的国内外研究现状,分析评述了以高分子树脂、硅胶微粒、生物质、纳米颗粒和多孔介孔材料为基体的重金属螯合复合材料的国内外研究进展状况和存在问题。提出重金属螯合复合材料今后研究方向为:基体材料的选择应重点考虑材料来源、价格和性能,优先选择生物质材料、纳米材料和多孔介料;选择和探索新的高效螯合功能基团;复合材料制备和使用过程中应注意材料与环境的相容性,不产生环境污染。

  7. Biomolecule-assisted exfoliation and dispersion of graphene and other two-dimensional materials: a review of recent progress and applications.

    Science.gov (United States)

    Paredes, J I; Villar-Rodil, S

    2016-08-25

    Direct liquid-phase exfoliation of layered materials by means of ultrasound, shear forces or electrochemical intercalation holds enormous promise as a convenient, cost-effective approach to the mass production of two-dimensional (2D) materials, particularly in the form of colloidal suspensions of high quality and micrometer- and submicrometer-sized flakes. Of special relevance due to environmental and practical reasons is the production of 2D materials in aqueous medium, which generally requires the use of certain additives (surfactants and other types of dispersants) to assist in the exfoliation and colloidal stabilization processes. In this context, biomolecules have received, in recent years, increasing attention as dispersants for 2D materials, as they provide a number of advantages over more conventional, synthetic surfactants. Here, we review research progress in the use of biomolecules as exfoliating and dispersing agents for the production of 2D materials. Although most efforts in this area have focused on graphene, significant advances have also been reported with transition metal dichalcogenides (MoS2, WS2, etc.) or hexagonal boron nitride. Particular emphasis is placed on the specific merits of different types of biomolecules, including proteins and peptides, nucleotides and nucleic acids (RNA, DNA), polysaccharides, plant extracts and bile salts, on their role as efficient colloidal dispersants of 2D materials, as well as on the potential applications that have been explored for such biomolecule-exfoliated materials. These applications are wide-ranging and encompass the fields of biomedicine (photothermal and photodynamic therapy, bioimaging, biosensing, etc.), energy storage (Li- and Na-ion batteries), catalysis (e.g., catalyst supports for the oxygen reduction reaction or electrocatalysts for the hydrogen evolution reaction), or composite materials. As an incipient area of research, a number of knowledge gaps, unresolved issues and novel future

  8. Biomolecule-assisted exfoliation and dispersion of graphene and other two-dimensional materials: a review of recent progress and applications.

    Science.gov (United States)

    Paredes, J I; Villar-Rodil, S

    2016-08-25

    Direct liquid-phase exfoliation of layered materials by means of ultrasound, shear forces or electrochemical intercalation holds enormous promise as a convenient, cost-effective approach to the mass production of two-dimensional (2D) materials, particularly in the form of colloidal suspensions of high quality and micrometer- and submicrometer-sized flakes. Of special relevance due to environmental and practical reasons is the production of 2D materials in aqueous medium, which generally requires the use of certain additives (surfactants and other types of dispersants) to assist in the exfoliation and colloidal stabilization processes. In this context, biomolecules have received, in recent years, increasing attention as dispersants for 2D materials, as they provide a number of advantages over more conventional, synthetic surfactants. Here, we review research progress in the use of biomolecules as exfoliating and dispersing agents for the production of 2D materials. Although most efforts in this area have focused on graphene, significant advances have also been reported with transition metal dichalcogenides (MoS2, WS2, etc.) or hexagonal boron nitride. Particular emphasis is placed on the specific merits of different types of biomolecules, including proteins and peptides, nucleotides and nucleic acids (RNA, DNA), polysaccharides, plant extracts and bile salts, on their role as efficient colloidal dispersants of 2D materials, as well as on the potential applications that have been explored for such biomolecule-exfoliated materials. These applications are wide-ranging and encompass the fields of biomedicine (photothermal and photodynamic therapy, bioimaging, biosensing, etc.), energy storage (Li- and Na-ion batteries), catalysis (e.g., catalyst supports for the oxygen reduction reaction or electrocatalysts for the hydrogen evolution reaction), or composite materials. As an incipient area of research, a number of knowledge gaps, unresolved issues and novel future

  9. Thermal performance and radio-frequency transmissivity of candidate ablation materials for S-band antenna window application on manned spacecraft

    Science.gov (United States)

    Tillian, D. J.; Cubley, H. D.

    1970-01-01

    A test program was conducted in the MSC 1.5 MW arc-heated facility to evaluate the thermal performance of ablation materials having potential application as radio frequency windows. These tests were conducted for the improvement of omnidirectional antenna operating characteristics during atmospheric reentry. Since a full scale model of the Apollo command service module was available for antenna tests, this mockup was used as a basic for the tests. Test models were subjected to heating conditions simulating the nominal lunar return trajectory (AS-501) and the design trajectories, high heat load and high heating rate. RF measurements were made before and after the arc jet tests to measure attenuation effects due to the thermal degradation of the materials under consideration. The test program demonstrated that additional development is required in materials technology to achieve an ablative system with both good RF transmission characteristics and thermal-structural integrity.

  10. Application progress of solid 29Si, 27Al NMR in the research of cement-based materials

    International Nuclear Information System (INIS)

    Background: The solid-state Nuclear Magnetic Resonance (NMR) is an effective method for the research of cement-based materials. Now it focuses on using solid 29Si and 27Al NMR to research the hydration structure of the cement-based materials in cement chemistry. Purpose: A theoretical guidance is proposed for solid 29Si and 27Al NMR technology used in cement chemistry research. Methods: We reviewed the application of solid 29Si and 27Al NMR in the cement-based materials and analyzed the problem among the researches. Results: This paper introduced an fundamental, relevant-conditions and basic parameters of NMR, and studied the technical parameters of solid 29Si and 27Ai NMR together with the relationship among the hydration structure of cement based material. Moreover, this paper reviewed the related domestic and overseas achievements in the research of hydration structure of the cement-based materials using solid 29Si and 27Al NMR. Conclusion: There were some problems in the research on cement-based materials by technology of solid 29Si and 27Al NMR. NMR will promote the Hydration theory of cement-based material greatly. (authors)

  11. Analytical methods for fissionable material determinations in the nuclear fuel cycle. Progress report, October 1, 1978-September 30, 1979

    International Nuclear Information System (INIS)

    Work continues on the development of dissolution techniques for difficult-to-dissolve nuclear materials, the development of methods and automated instruments for plutonium, uranium, and thorium determinations, and the preparation of plutonium materials for the Safeguards Analytical Laboratory Evaluation (SALE) program and distribution by the National Bureau of Standards (NBS) as standard reference materials (SRMs). We are measuring the loner plutonium isotope half-lives, evaluating the isotope correlation techniques and the chemistry involved in the mass-spectrometric ion-bead techniques, and analyzing the SALE uranium materials. Completed subtasks include evaluations of various Teflon materials to recommend those acceptable for the dissolution apparatus developed at LASL, investigations of laser-enhanced dissolution of refractory materials, determinations of diverse ion effects on the microgram-sensitive method for determining uranium, fabrication of the first automated controlled-potential coulometric analyzer for determining plutonium, preparation of a 244Pu material for distribution by NBS as a SRM, and determination of the half-life of 239Pu. Work has been started on a spectrophotometric method for determining microgram quantities of plutonium, a microcomplexometric titration method for determining uranium, the use of new reagents for separations of plutonium, the preparation and packaging of a new lot of high-purity plutonium metal for distribution by NBS as a plutonium chemical SRM, and determination of half-lives of other plutonium isotopes

  12. Progress in development of coated indexable cemented carbide inserts for machining of iron based work piece materials

    Science.gov (United States)

    Czettl, C.; Pohler, M.

    2016-03-01

    Increasing demands on material properties of iron based work piece materials, e.g. for the turbine industry, complicate the machining process and reduce the lifetime of the cutting tools. Therefore, improved tool solutions, adapted to the requirements of the desired application have to be developed. Especially, the interplay of macro- and micro geometry, substrate material, coating and post treatment processes is crucial for the durability of modern high performance tool solutions. Improved and novel analytical methods allow a detailed understanding of material properties responsible for the wear behaviour of the tools. Those support the knowledge based development of tailored cutting materials for selected applications. One important factor for such a solution is the proper choice of coating material, which can be synthesized by physical or chemical vapor deposition techniques. Within this work an overview of state-of-the-art coated carbide grades is presented and application examples are shown to demonstrate their high efficiency. Machining processes for a material range from cast iron, low carbon steels to high alloyed steels are covered.

  13. Chemistry and Materials Science progress report, first half FY 1992. Weapons-Supporting Research and Laboratory Directed Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    This report contains sections on: Fundamentals of the physics and processing of metals; interfaces, adhesion, and bonding; energetic materials; plutonium research; synchrotron radiation-based materials science; atomistic approach to the interaction of surfaces with the environment: actinide studies; properties of carbon fibers; buried layer formation using ion implantation; active coherent control of chemical reaction dynamics; inorganic and organic aerogels; synthesis and characterization of melamine-formaldehyde aerogels; structural transformation and precursor phenomena in advanced materials; magnetic ultrathin films, surfaces, and overlayers; ductile-phase toughening of refractory-metal intermetallics; particle-solid interactions; electronic structure evolution of metal clusters; and nanoscale lithography induced chemically or physically by modified scanned probe microscopy.

  14. Analysis of Sustainable Materials Used in Ecovillages:Review of Progress in BedZED and Masdar City

    Institute of Scientific and Technical Information of China (English)

    ZHU Dan; Michael Kung; Bill Whiteford; Alex Boswell-Ebersole

    2012-01-01

    This paper explores reclaimed and recycled material used in ecovillages.The models discussed in this paper include BedZED in the United Kingdom and Masdar City in the Middle East.These two communities contain features characterized by the sustainable principles of the ecovillage concept by using nontraditional building materials.The creations of more ecovillages,along with the growth of current ecovillages,play an important role in positively solvening environmental and social problems.The sustainable materials used in the ecovillages also act as a model for communities wishing to implement sustainable development.

  15. Development of BaAl{sub x}Fe{sub 12−x}O{sub 19}-NPR nanocomposite as an efficient absorbing material in the X-band

    Energy Technology Data Exchange (ETDEWEB)

    Ozah, S.; Bhattacharyya, N.S., E-mail: nidhisbhatta@gmail.com

    2015-01-15

    An efficient BaAl{sub x}Fe{sub 12−x}O{sub 19}- novolac phenolic resin (NPR) nanocomposite material is developed to use as absorbing material in the X band. The material developed has a hexagonal structure of nanosize aluminium substituted barium ferrite, as is confirmed by X-ray diffraction pattern studies. The average grain size of barium nanoparticles is found to be ∼26 nm. Measurement of complex permittivity and complex permeability in the X-band indicates increase of the properties with increase in Al{sup 3+} ions in the ferrite. A measured absorption study has been carried out on absorber fabricated on a metal backing based on the transmission line theory. Substitution of Fe{sup 3+} with Al{sup 3+} is found to increase the absorption properties of barium ferrite. Reflection loss measurement of the samples shows an enhancement of absorption from −27.56 dB to −40.06 dB with the variation of Al{sup 3+} substitution, x=1.0–1.6 in the BaAl{sub x}Fe{sub 12−x}O{sub 19} in NPR matrix. - Highlights: • BaAl{sub x}Fe{sub 12−x}O{sub 19}-NPR nanocomposite is developed as a microwave absorbing material. • Thickness optimization is carried out for maximum absorption using TLM. • Maximum RLc is obtained for x=1.6 i.e. the maximum measured reflection loss for the BaAl{sub x}Fe{sub 12−x}O{sub 19}-NPR nanocomposite is obtained for x=1.6. • Maximum RL{sub m} for x=1.6 with 2 mm thickness is −40.06 dB at 9.56 GHz.

  16. Kink Band Instability and Propagation in Layered Structures

    NARCIS (Netherlands)

    Wadee, M.A.; Hunt, G.W.; Peletier, M.A.

    2003-01-01

    A recent two-dimensional prototype model for the initiation of kink banding in compressed layered structures is extended to embrace the two propagation mechanisms of band broadening and band progression. As well as interlayer friction, overburden pressure and layer bending energy, the characteristic

  17. A rheometer for measuring the material moduli for granular solids. Quarterly progress report, December 1, 1992--February 28, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rajajopal, K.R.

    1996-02-01

    The design of an orthogonal rheometer for measuring the properties of granular solids is described. A section is presented on the constitutive modeling of granular materials based on continuum theory.

  18. Heavy vehicle propulsion system materials program semi-annual progress report for October 1997 through March 1998

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R.

    1998-06-01

    The purpose of the Heavy Vehicle Propulsion System materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1--3 trucks to realize a 35{percent} fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7--8 trucks. The Office of Transportation Technologies, Office of Heavy Vehicle Technologies (OTT OHVT) has an active program to develop the technology for advanced LE-55 diesel engines with 55{percent} efficiency and low emissions levels of 2.0 g/bhp-h NO{sub x} and 0.05 g/bhp-h particulates. The goal is also for the LE-55 engine to run on natural gas with efficiency approaching that of diesel fuel. The LE-55 program is being completed in FY 1997 and, after approximately 10 years of effort, has largely met the program goals of 55{percent} efficiency and low emissions. However, the commercialization of the LE-55 technology requires more durable materials than those that have been used to demonstrate the goals. Heavy Vehicle Propulsion System Materials will, in concert with the heavy-duty diesel engine companies, develop the durable materials required to commercialize the LE-55 technologies.

  19. 磁性介孔材料的研究进展%Progress of Magnetic Mesoporous Materials

    Institute of Scientific and Technical Information of China (English)

    刘峰; 田华; 贺军辉; 刘红缨

    2013-01-01

    磁性介孔材料兼具介孔材料和磁性材料的双重优势,如高比表面积、孔径均一、高吸附性和可磁分离性,具有广泛的应用前景和重大的研究意义,受到化学和材料工作者的极大关注.本文综述了磁性介孔材料的制备方法及其改性研究,同时介绍了磁性介孔材料在污水处理、催化反应、药物控释和生物分子的分离提纯等领域的一些应用进展.%Magnetic mesoporous materials exhibit properties of both mesoporous materials and magnetic materials, such as high specific surface area, uniform pore size, high adsorbability and unique magnetic property. Magnetic mesoporous materials are of great importance due to their numerous applications. In this paper, studies on the fabrication and modification of magnetic mesoporous materials were reviewed. Their applications in waste water treatment, catalytic reactions, controlled drug release, and separation and purification of biological molecules were also introduced.

  20. Research progress in high voltage spinel LiNi0.5Mn1.5O4 material

    International Nuclear Information System (INIS)

    Lithium-ion batteries are now considered to be the technology of choice for future hybrid electric and full electric vehicles to address global warming. LiCoO2 has been the most widely used cathode material in commercial lithium-ion batteries. Since LiCoO2 has economic and environmental issues, intensive research has been directed towards the development of alternative low cost, environmentally friendly cathode materials as possible replacement of LiCoO2. Among them, spinel LiNi0.5Mn1.5O4 material is one of the promising and attractive cathode materials for next generation lithium-ion batteries because of its high voltage (4.7 V), acceptable stability, and good cycling performance. Research advances in high voltage spinel LiNi0.5Mn1.5O4 are reviewed in this paper. Developments in synthesis, structural characterization, effect of doping, and effect of coating are presented. In addition to conventional synthesis methods, several alternative synthesis methods are also summarized. Apart from battery performance, the application of spinel LiNi0.5Mn1.5O4 material in asymmetric supercapacitors is also discussed. (author)

  1. Dislocation model of nucleation and development of slip bands and their effect on service life of structural materials subject to cyclic loading

    Science.gov (United States)

    Shetulov, D. I.; Andreev, V. V.; Myasnikov, A. M.

    2015-12-01

    Most of the destructions of machine parts are of fatigue character. Under cyclic loading, the surface layer, in which hardening-softening processes rapidly occur, is formed almost at once after its beginning. The interaction of plastic-deformation traces with each other and with other structural elements, such as grains, results in the formation of a characteristic microstructure of the machine-part surface subject to cyclic loadings. The character of accumulation of slip bands and their shape (narrow, wide, twisting, and broken) depends on the conditions under which (under what factors) the cyclic loading occurs. The fatigue-resistance index expressed in terms of the slope of left portion of the fatigue curve linearized in logarithmic coordinates also depends on the set of relevant factors. The dependence of the surface damageability on the fatigue resistance index makes it possible to implement the method of predicting the fatigue curve by the description of the factors acting on a detail or construction. The position of the inflection point on the curve in the highcycle fatigue region (the endurance limit and the number of loading cycles, the ordinate and abscissa of the inflection point on the fatigue curve, respectively) also depends on the set of relevant factors. In combination with the previously obtained value of the slope of the left portion of the curve in the high-cycle fatigue region, this makes it possible to construct an a priori fatigue curve, thus reducing the scope of required fatigue tests and, hence, high expenses because of their long duration and high cost. The scope of tests upon using the developed method of prediction may be reduced to a minimum of one or two samples at the predicted level of the endurance limit.

  2. Dislocation model of nucleation and development of slip bands and their effect on service life of structural materials subject to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Shetulov, D. I.; Andreev, V. V., E-mail: vyach.andreev@mail.ru; Myasnikov, A. M. [Nizhny Novgorod State Technical University (Russian Federation)

    2015-12-15

    Most of the destructions of machine parts are of fatigue character. Under cyclic loading, the surface layer, in which hardening–softening processes rapidly occur, is formed almost at once after its beginning. The interaction of plastic-deformation traces with each other and with other structural elements, such as grains, results in the formation of a characteristic microstructure of the machine-part surface subject to cyclic loadings. The character of accumulation of slip bands and their shape (narrow, wide, twisting, and broken) depends on the conditions under which (under what factors) the cyclic loading occurs. The fatigue-resistance index expressed in terms of the slope of left portion of the fatigue curve linearized in logarithmic coordinates also depends on the set of relevant factors. The dependence of the surface damageability on the fatigue resistance index makes it possible to implement the method of predicting the fatigue curve by the description of the factors acting on a detail or construction. The position of the inflection point on the curve in the highcycle fatigue region (the endurance limit and the number of loading cycles, the ordinate and abscissa of the inflection point on the fatigue curve, respectively) also depends on the set of relevant factors. In combination with the previously obtained value of the slope of the left portion of the curve in the high-cycle fatigue region, this makes it possible to construct an a priori fatigue curve, thus reducing the scope of required fatigue tests and, hence, high expenses because of their long duration and high cost. The scope of tests upon using the developed method of prediction may be reduced to a minimum of one or two samples at the predicted level of the endurance limit.

  3. Dislocation model of nucleation and development of slip bands and their effect on service life of structural materials subject to cyclic loading

    International Nuclear Information System (INIS)

    Most of the destructions of machine parts are of fatigue character. Under cyclic loading, the surface layer, in which hardening–softening processes rapidly occur, is formed almost at once after its beginning. The interaction of plastic-deformation traces with each other and with other structural elements, such as grains, results in the formation of a characteristic microstructure of the machine-part surface subject to cyclic loadings. The character of accumulation of slip bands and their shape (narrow, wide, twisting, and broken) depends on the conditions under which (under what factors) the cyclic loading occurs. The fatigue-resistance index expressed in terms of the slope of left portion of the fatigue curve linearized in logarithmic coordinates also depends on the set of relevant factors. The dependence of the surface damageability on the fatigue resistance index makes it possible to implement the method of predicting the fatigue curve by the description of the factors acting on a detail or construction. The position of the inflection point on the curve in the highcycle fatigue region (the endurance limit and the number of loading cycles, the ordinate and abscissa of the inflection point on the fatigue curve, respectively) also depends on the set of relevant factors. In combination with the previously obtained value of the slope of the left portion of the curve in the high-cycle fatigue region, this makes it possible to construct an a priori fatigue curve, thus reducing the scope of required fatigue tests and, hence, high expenses because of their long duration and high cost. The scope of tests upon using the developed method of prediction may be reduced to a minimum of one or two samples at the predicted level of the endurance limit

  4. 电磁屏蔽材料的研究进展%Research Progress of Electromagnetic Interference Shielding Materials

    Institute of Scientific and Technical Information of China (English)

    于名讯; 徐勤涛; 庞旭堂; 连军涛; 刘玉凤

    2012-01-01

    The significance of electromagnetic interference (EMI) shielding material was explained. The properties and characters of the electromagnetic interference shielding material such as the style of surface layer, filling, intrinsic conductive polymer, conductive fabric and transparent conductive film were reviewed. The trend of research and development of the EMI shielding material is introduced.%阐述了研究电磁屏蔽材料的重要性.综述了表层导电型、填充复合型、本征型导电高分子、导电织物、透明导电薄膜等电磁屏蔽材料的性能及特点,简要阐述了电磁屏蔽材料的发展趋势.

  5. Evaluation of materials for retention of sodium and core debris in reactor systems. Annual progress report, September 1977-December 1978

    International Nuclear Information System (INIS)

    This report considers some of the consequences of a hypothetical core disruptive accident in a nuclear reactor. The interactions expected between molten core debris, liquid sodium, and materials that might be employed in an ex-vessel sacrificial-bed or in the reactor building are discussed. Experimental work performed for NRC by Sandia Laboratories and Hanford Engineering Development Laboratory on the interactions between liquid sodium and basalt concrete is reviewed. Studies of molten steel interactions with concrete at Sandia Laboratories and molten UO2 interactions with concrete at The Aerospace Corporation are also discussed. The potential of MgO for use in core containment is discussed and refractory materials other than MgO are reviewed. Finally, results from earlier experiments with molten core debris and various materials performed at The Aerospace Corporation are presented

  6. New materials by low temperature condensation. Progress report. [Department of Applied Physics and Information Science, Univ. of California, San Diego

    Energy Technology Data Exchange (ETDEWEB)

    Luo, H.L.

    1972-09-01

    The study of new materials prepared mostly by the technique of inert gas ion sputtering is reported. Heat capacity measurement was chosen as the basic tool for the study of material properties. Sputtering experiments were done on Nb/sub 3/Al and Nb/sub 3/(Al, Ge), Ag-base alloys with magnetic impurities, molybdenum-sulfide complex, and other metastable phases. Heat capacity measurements were made on V/sub 3/Si and Nb/sub 3/Sn, ZrZn/sub 2/, Mo isotopes, Mo-S complex, disordered systems, and sapphire and thin films. 3 figures, 1 table. (RWR)

  7. Chemistry and materials science progress report. Weapons-supporting research and laboratory directed research and development: FY 1995

    International Nuclear Information System (INIS)

    This report covers different materials and chemistry research projects carried out a Lawrence Livermore National Laboratory during 1995 in support of nuclear weapons programs and other programs. There are 16 papers supporting weapons research and 12 papers supporting laboratory directed research

  8. Chemistry and materials science progress report. Weapons-supporting research and laboratory directed research and development: FY 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    This report covers different materials and chemistry research projects carried out a Lawrence Livermore National Laboratory during 1995 in support of nuclear weapons programs and other programs. There are 16 papers supporting weapons research and 12 papers supporting laboratory directed research.

  9. Progress of highly efficient polymer photovoltaic materials%高效聚合物光伏材料研究进展

    Institute of Scientific and Technical Information of China (English)

    霍利军; 侯剑辉

    2012-01-01

    聚合物光伏电池因具有重量轻、成本低以及可制成柔性大面积器件等优点而具有广阔的应用前景.近年来,采用共轭聚合物作为光伏电池活性层材料的研究进展十分迅速.本文介绍了聚合物光伏电池的工作原理和器件结构,综述了聚合物材料作为给体,在体相异质结型光伏器件中的最新研究进展,并对今后进一步提高这类电池的能量转换效率问题进行了探讨.%Polymer solar cells (PSCs) have sparked extensive application prospects due to their potential advantages of making large area, light weight and flexible solar panels. In recent years, great progress in polymer photovoltaic materials has been achieved, and more and more new conjugated polymers were designed, synthesized and applied in PSCs. In this review, the device structures and principles of PSCs were introduced, and especially, recent progress in conjugated polymer active layer materials was reviewed in detail.

  10. Shear Banding of Complex Fluids

    Science.gov (United States)

    Divoux, Thibaut; Fardin, Marc A.; Manneville, Sebastien; Lerouge, Sandra

    2016-01-01

    Even in simple geometries, many complex fluids display nontrivial flow fields, with regions where shear is concentrated. The possibility for such shear banding has been known for several decades, but in recent years, we have seen an upsurge in studies offering an ever-more precise understanding of the phenomenon. The development of new techniques to probe the flow on multiple scales with increasing spatial and temporal resolution has opened the possibility for a synthesis of the many phenomena that could only have been thought of separately before. In this review, we bring together recent research on shear banding in polymeric and soft glassy materials and highlight their similarities and disparities.

  11. Progress of Electromagnetic Wave Absorbing Materials Based on Carbon%碳基吸波材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    李斌鹏; 王成国; 王雯

    2012-01-01

    传统吸波材料由于密度大、吸收频带窄使其应用受到限制,新型吸波材料的探索和研究将会成为吸波材料领域的主要发展方向.碳材料以其独特的物理化学性能一直备受关注.先进碳材料已成为新材料领域的发展重点.碳材料是最早用来吸收电磁波的材料之一,近年来碳基吸波材料的性能不断提高并应用于更多领域.介绍了碳基(石墨、炭黑、碳纤维、碳纳米管)吸波材料的性能,分析了各种吸波材料的主要特点,总结了近年来国内外碳基吸波材料的研究进展及发展趋势,展望了碳基吸波材料的发展前景.%The application of traditional microwave absorbing materials is limited due to their high densities and narrow absorbing bandwidth. And researches of novel microwave absorbing materials have become main development direction. Carbon materials have always been drawing the attention of material scientists and engineers because of their unique physical and chemical properties. Advanced carbon materials have become the focus of new materials. Carbon material is one of the earliest electromagnetic wave absorbing materials. Electromagnetic wave absorbing materials based on carbon have been improved a lot and applied in more fields in recent years. The properties of absorbing materials based on carbon (graphite, carbon black, carbon fiber, carbon nanotubes) are introduced, their main characteristics are analyzed, their progress and development trends at home and abroad in recent years are summarized, and finally the development of them is prospected.

  12. Joint research and development on toxic-material emergency response between ENEA and LLNL. 1982 progress report

    International Nuclear Information System (INIS)

    A summary is presented of current and future cooperative studies between ENEA and LLNL researchers designed to develop improved real-time emergency response capabilities for assessing the environmental consequences resulting from an accidental release of toxic materials into the atmosphere. These studies include development and evaluation of atmospheric transport and dispersion models, interfacing of data processing and communications systems, supporting meteorological field experiments, and integration of radiological measurements and model results into real-time assessments

  13. Progress in mass spectrometry for the analysis of set-off phenomena in plastic food packaging materials.

    Science.gov (United States)

    Aznar, Margarita; Alfaro, Pilar; Nerín, Cristina; Jones, Emrys; Riches, Eleanor

    2016-07-01

    In most cases, food packaging materials contain inks whose components can migrate to food by diffusion through the material as well as by set-off phenomena. In this work, different mass spectrometry approaches had been used in order to identify and confirm the presence of ink components in ethanol (95%) and Tenax(®) as food simulants. Three different sets of materials, manufactured with different printing technologies and with different structures, were analyzed. Sample analysis by ultra performance liquid chromatography mass spectrometry (UPLC-MS), using a quadrupole-time of flight (Q-TOF) as a mass analyser proved to be an excellent tool for identification purposes while ion mobility mass spectrometry (IM-MS) shown to be very useful for the confirmation of the candidates proposed. The results showed the presence of different non-volatile ink components in migration such as colorants (Solvent Red 49), plasticizers (dimethyl sebacate, tributyl o-acetyl citrate) or surfactants (SchercodineM, triethylene glycol caprilate). An oxidation product of an ink additive (triphenyl phosphine oxide) was also detected. In addition, a surface analysis technique, desorption electrospray mass spectrometry (DESI-MS), was used for analyzing the distribution of some ink components (tributyl o-acetyl citrate Schercodine L, phthalates) in the material. The detection of some of these compounds in the back-printed side confirmed the transference of this compound from the non-food to the food contact side. The results also showed that concentration of ink migrants decreased when an aluminum or polypropylene layer covered the ink. When aluminum was used, concentration of most of ink migrants decreased, and for 5 out of the 9 even disappeared. PMID:27215462

  14. The Progress of Sodium-Ion Battery Anode Material%钠离子电池负极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    张洁; 杨占旭

    2016-01-01

    Sodium ion batteries have attracted tremendous attentions due to its rich resources,low cost,high efficiency and good chemical stability,and can satisfy people's demand for energy in the new era,which are considered a top alternative to lithium-ion batteries.The research progress on sodium ion battery anode materials are reviewed in details in this paper, including carbon-based materials,low voltage metal phosphates,the sodium storage alloys,metal oxides,titanium-based materials,and other negative electrode materials.Then the characteristics of anode materials are discussed.Finally,some future directions for sodium-ion battery anode materials are pointed out.%钠离子电池具有资源丰富、成本低、效率高、化学性能稳定等优点,成为锂离子电池 的理想替代品.主要阐述了钠离子电池负极材料的研究进展,包括碳基负极材料、低电压金属磷酸盐负极材料、合金类储钠负极材料、金属氧化物负极材料、钛酸盐类负极材料及其他负极材料,并对各类负极材料的性能进行了评价,最后对钠离子电池负极材料的发展方向做出了展望.

  15. 量子点显示材料的研究进展%Research Progress of Quantum Dots Display Materials

    Institute of Scientific and Technical Information of China (English)

    魏文君; 曹元成; 刘继延; 尤庆亮

    2015-01-01

    半导体量子点(quantum dots ,QDs)由于具有独特的发光特性而在显示器材料领域具有极高的应用价值。相比传统显示材料,QDs光器件具有色彩明亮、纯色性好和低能耗的优点,是理想的显示器材料。结合已有的工作介绍了半导体QDs的发光原理、发光特性和常见的制备方法,同时也介绍了目前QDs显示器的技术发展现状和面临的挑战,并对其在柔性显示器方面的发展前景进行了展望。%Semiconductor quantum dots(QDs)have unique optical properties,so they have very high application value in displaying material domain. Comparing with traditional displaying materials ,QDs optical devices have the advantages such as brightness ,color purity and energy efficiency ,which make them the ideal displaying materials. Based on the current works ,introduces the optical principles ,opti⁃cal properties and common synthesis methods of QDs ,also introduces the developments and challenges of QDs,and outlook the application of the QDs on flexible displayer.

  16. Mechanical properties of structural materials for FBR sodium application. Semi-annual progress report for period ending January 31, 1982

    International Nuclear Information System (INIS)

    Metallographic evaluations of the CRBR core barrel forging material, creep rupture tested at 5380C in air, were performed. The majority of the specimens had a knobby appearance on the surface of the gage section. The stress-rupture life for sodium pre-exposed Type 316 stainless steel performed at 5380C in flowing sodium is increased by a factor of at least three at a stress of 275.8 MPa (40.0 ksi) when compared to tests in sodium for as-received material (mill annealed) at the same conditions. Creep-rupture tests of mill annealed type 316 stainless steel in flowing sodium at 5930C and 224.1 MPa (32.5 ksi), involving different gage diameters of 0.25, 0.15, and 0.10 inches, were evaluated. A creep-rupture test of an alloy 718 specimen tested at 6490C and 344.7 MPa (50.0 ksi) in the flowing sodium, after exposure to flowing sodium at 6490C for 10,000 hours, ruptured after 9617 hours. It is estimated that after nearly 20,000 hours in sodium, the rupture life was reduced approximately 30% when compared to results for as-received material tested in flowing sodium

  17. Progress in Solid Tritium Breeder Materials%固态氚增殖剂研究进展

    Institute of Scientific and Technical Information of China (English)

    赵林杰; 肖成建; 陈晓军; 龚宇; 彭述明; 龙兴贵

    2015-01-01

    增殖包层作为实现可控核聚变燃料“自持”的关键,不仅能实现氚的增殖,而且起着能量转换的作用,氚增殖剂是其中最重要的功能材料。本文从材料体系的制备、性能以及改性总结了固态氚增殖剂的发展趋势。同时,基于当前的研究现状对固态氚增殖剂的发展进行了展望。%The breeding blanket is a key component of the fusion reactor because it directly involves tritium breeding and energy extraction.Tritium breeding material is one of the most important functional materials.Herein,we reviewed the trends in solid tritium breeder development,including the fabrication,properties and modification.Meanwhile,the focus of the solid tritium breeder materials were prospected based on the current research situa-tion.

  18. Corrosion behaviour of container materials for geological disposal of high-level waste. Joint annual progress report 1983

    International Nuclear Information System (INIS)

    Within the framework of the Community R and D programme on management and storage of radioactive waste (shared-cost action), a research activity is aiming at the assessment of corrosion behaviour of potential container materials for geological disposal of vitrified high-level wastes. In this report, the results obtained during the year 1983 are described. Research performed at the Studiecentrum voor Kernenergie/Centre d'Etudes de l'Energie Nucleaire (SCK/CEN) at Mol (B), concerns the corrosion behaviour in clay environments. The behaviour in salt is tested by the Kernforschungszentrum (KfK) at Karlsruhe (D). Corrosion behaviour in granitic environments is being examined by the Commissariat a l'Energie Atomique (CEA) at Fontenay-aux-Roses (F) and the Atomic Energy Research Establishment (AERE) at Harwell (UK); the first is concentrating on corrosion-resistant materials and the latter on corrosion-allowance materials. Finally, the Centre National de la Recherche Scientifique (CNRS) at Vitry (F) is examining the formation and behaviour of passive layers on the metal alloys in the various environments

  19. Synthesis of Submicron Hexagonal Plate-Type SnS2 and Band Gap-Tuned Sn1−xTixS2 Materials and Their Hydrogen Production Abilities on Methanol/Water Photosplitting

    Directory of Open Access Journals (Sweden)

    Kang Min Kim

    2014-01-01

    Full Text Available SnS2 and Sn1−xTixS2 (x = 0, 0.1, 0.3, 0.5, and 0.7 mol materials were designed using solvothermal method with the aim to enhance hydrogen production from water/methanol water photosplitting. Scanning electron microscopy revealed hexagonal plates with one side, 3.0 μm in length, in the SnS2 materials. Pure SnS2 showed absorption band edges of above 660 nm, and the absorption was shifted to low wavelengths with the insertion of Ti ions. The evolution of H2 from MeOH/H2O (1 : 1 photosplitting over SnS2 hexagonal plates in the photocatalytic liquid system was 0.016 mL h−1 g−1, and the evolutions were enhanced in Sn1−xTixS2. In particular, 0.049 mL h−1 g−1 of H2 gas was produced in Sn0.7Ti0.3S2 without electrolytes and it increased significantly to more than 90.6% (0.47 mL h−1 g−1 evolutions at higher pH using 0.1 M of KOH. Based on the UV-visible absorption spectra, the high photocatalytic activity of Sn1−xTixS2 was attributed to the existence of an appropriate band-gap state that retarded recombination between the electrons and holes.

  20. Bonds and bands in semiconductors

    CERN Document Server

    Phillips, Jim

    2009-01-01

    This classic work on the basic chemistry and solid state physics of semiconducting materials is now updated and improved with new chapters on crystalline and amorphous semiconductors. Written by two of the world's pioneering materials scientists in the development of semiconductors, this work offers in a single-volume an authoritative treatment for the learning and understanding of what makes perhaps the world's most important engineered materials actually work. Readers will find: --' The essential principles of chemical bonding, electron energy bands and their relationship to conductive and s

  1. Study and Progress of Nuclear Power Cable Materials%核电站电缆料的研究进展

    Institute of Scientific and Technical Information of China (English)

    武卫莉; 虞文品; 田磊

    2011-01-01

    According to the type of nuclear power cable, the classification, performance, process technology and research status at home and abroad on the nuclear power cable materials are introduced. It is found that the insulation material of the nuclear power cable is mainly cross-linked polyethyleneC XLPE) and silicone rubber(or silicone rubber composites), with which have thermal properties, electric insulation, low-temperature resistance, chemical and radiation resistance; and has low smoke non-halogen, flame and environment resistance; its main process is extrusion method, which is a simple production technology and cost low. At last, the development trend of nuclear power cable materials is previewed.%依据核电站电缆的种类,介绍了核电站电缆料的种类、性能、生产工艺和国内外的研究现状.研究发现,制备核电站电缆绝缘料主要用交联聚乙烯(XLPE)和硅橡胶(或硅橡胶复合材料),此两种原料具有优良的耐热性、电绝缘性、耐低温性、耐化学性和良好的耐辐射性;核电站电缆料应具有低烟无卤、耐阻燃性和耐环境性能;其制备方法主要是挤出法,此方法生产工艺简单、成本低.最后展望了核电站电缆料的发展趋势.

  2. Enforcement actions: Significant actions resolved, material licensees. Semiannual progress report, July--December 1997; Volume 16, Number 2, Part 3

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during the period (July--December 1997) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  3. Enforcement actions: Significant actions resolved material licensees (non-medical). Quarterly progress report, October 1994--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October - December 1994) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees (non-medical) with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication.

  4. Enforcement actions: Significant actions resolved material licensees (non-medical). Quarterly progress report, October 1994--December 1994

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October - December 1994) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees (non-medical) with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  5. Enforcement actions: Significant actions resolved, material licensees. Semiannual progress report, July--December 1997; Volume 16, Number 2, Part 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    This compilation summarizes significant enforcement actions that have been resolved during the period (July--December 1997) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to material licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication.

  6. Direct band gap silicon allotropes.

    Science.gov (United States)

    Wang, Qianqian; Xu, Bo; Sun, Jian; Liu, Hanyu; Zhao, Zhisheng; Yu, Dongli; Fan, Changzeng; He, Julong

    2014-07-16

    Elemental silicon has a large impact on the economy of the modern world and is of fundamental importance in the technological field, particularly in solar cell industry. The great demand of society for new clean energy and the shortcomings of the current silicon solar cells are calling for new materials that can make full use of the solar power. In this paper, six metastable allotropes of silicon with direct or quasidirect band gaps of 0.39-1.25 eV are predicted by ab initio calculations at ambient pressure. Five of them possess band gaps within the optimal range for high converting efficiency from solar energy to electric power and also have better optical properties than the Si-I phase. These Si structures with different band gaps could be applied to multiple p-n junction photovoltaic modules. PMID:24971657

  7. Quarterly Technical Progress Report of Radioisotope Power System Materials Production and Technology Program tasks for April 2000 through June 2000

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.P.

    2000-10-23

    The Office of Space and Defense Power Systems (OSDPS) of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. For the Cassini Mission, for example, ORNL was involved in the production of carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVSs) and weld shields (WSs). This quarterly report has been divided into three sections to reflect program guidance from OSDPS for fiscal year (FY) 2000. The first section deals primarily with maintenance of the capability to produce flight quality carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, clad vent sets (CVSs), and weld shields (WSs). In all three cases, production maintenance is assured by the manufacture of limited quantities of flight quality (FQ) components. The second section deals with several technology activities to improve the manufacturing processes, characterize materials, or to develop technologies for two new RPS. The last section is dedicated to studies of the potential for the production of 238Pu at ORNL.

  8. 石墨烯/偶氮杂化材料研究进展%Progress on graphene/azobenzene hybrid materials

    Institute of Scientific and Technical Information of China (English)

    王东瑞; 王晓工

    2012-01-01

    Graphene, a true two dimensional nanomaterial with the layer thickness of one atom, has showed many outstanding properties and aroused tremendous research enthusiasm. Azobenzene-containing polymers and other materials have also attracted considerable attention because of the unique photoresponsive properties. Graphene/ azobenzene hybrids materials can combine interesting properties of graphere and azobenzene-containing materials and have been studied in authors and other laboratories in recent years. This review highlighted some recent research progresses in this area. The content of this article included the preparations of graphene/azobenzene hybrids materials through surface-grafting of azo polymers, covalent-bonding modification with low-molecular-weight azo compounds and electrostatic layer-by-layer deposition. The photoresponsive properties and application in the electronchemical energy storage device of the materials were also reviewed in some detail.%石墨烯作为一种新型二维平面纳米材料,表现出许多优异的物理性质.含偶氮苯的化合物和聚合物作为功能材料具有独特的光响应性质.将石墨烯的特性与偶氮材料的光响应性相结合,有望发展一类具有卓越性能的新型光电功能材料.本文总结了石墨烯/偶氮杂化材料这一研究方向的最新进展,重点介绍了杂化材料的制备、表征和光电功能性质等,并简要展望了这类材料的发展前景.

  9. Metal band drives in spacecraft mechanisms

    Science.gov (United States)

    Maus, Daryl

    1993-05-01

    Transmitting and changing the characteristics of force and stroke is a requirement in nearly all mechanisms. Examples include changing linear to rotary motion, providing a 90 deg change in direction, and amplifying stroke or force. Requirements for size, weight, efficiency and reliability create unique problems in spacecraft mechanisms. Flexible metal band and cam drive systems provide powerful solutions to these problems. Band drives, rack and pinion gears, and bell cranks are compared for effectiveness. Band drive issues are discussed including materials, bend radius, fabrication, attachment and reliability. Numerous mechanisms are shown which illustrate practical applications of band drives.

  10. 微反应器制备无机材料的应用进展%Application progress of microreactors in synthesis of inorganic materials

    Institute of Scientific and Technical Information of China (English)

    曹寅; 杨晖

    2011-01-01

    简述了微反应器近些年的发展及微反应器的定义、分类和优点.综述了微反应器在制备无机颗粒材料方面的研究进展,介绍了制备过程中一些可控因素对产物的影响,着重介绍了某些微反应器与间歇反应器在制备无机颗粒材料方面的差异,总结了微反应器在合成材料上的优势,并且对微反应器在无极颗粒材料合成中的应用前景做了展望.%Development in recent years,definition, classification, and advantages of microreactors were briefly introduced. Application progress of microreactors in synthesis of inoganic materials was reviewed and the influence of some controllable factors on products during the synthesis process were discussed in detail. Differences between inorganic materials prepared by certain microreactor and by batch reactor were emphatically elaborated. Prospect of the application of microreactors in synthesis of inorganic materials was also forecasted.

  11. 制动用有机摩擦材料的研究进展%Progress in Research of Organic Frictional Materials for Automobile and Train Braking

    Institute of Scientific and Technical Information of China (English)

    丛培红; 吴行阳; 卜娟; 李同生

    2011-01-01

    随着社会的不断发展和进步,人们对车辆的运行速度、安全性、舒适度和环保化等提出了更高的要求,迫切需要进一步提高制动用摩擦材料的综合性能本文综述了有机黏结剂、增强纤维、摩擦性能调节剂和填料等有机摩擦材料4大类组分的研究进展,介绍了该领域的一些理论研究工作,希望为我国高性能有机摩擦材料的研制提供一些资料积累和思路.%With the development and advancement of society, higher speed and safety, more comfortable and environment friendly are required for automobiles and trains. It is urgent to improve the integrating properties of brake friction materials.This paper reviews the progress in research of the four components in the organic frictional materials, i.e. organic binders,reinforcement fibers, friction modified agents and fillers, also introduces some theory studies in this field, and desires to provide some information accumulation and research ideas for developing high performance friction materials.

  12. Progress in New Biomass-based Functional Carbon Materials%功能性生物质基碳素新材料

    Institute of Scientific and Technical Information of China (English)

    刘树和; 赵淑春

    2012-01-01

    较为系统地综述了以生物质为原料制备功能性生物质基碳素新材料的方法及其应用的研究进展.着重介绍了干法碳化和湿法碳化制备生物质基碳材料,并阐述了生物质基碳材料在吸附、陶瓷化、电磁屏蔽和吸波、电化学储能(锂离子电池和电化学电容器)及光催化等领域的应用.提出了生物质基碳素新材料今后的研究方向,展望了其发展前景.%The progress of synthesis and application of new biomass-based functional carbon materials are systematically reviewed. Main focuses are on preparation methods of new carbon materials through carbonization of bio-mass by dry method and wet method, and their applications in the field of adsorption, woodceramics, electromagnetic shielding and wave absorption, electrochemical energy storage, and photocatalysis, both at home and abroad in recent years. The future studies on the new biomass-based functional carbon materials are suggested and their developing trend is prospected.

  13. 电致变色材料、器件及应用研究进展%Research Progress in Electrochromic Materials, Devices and Applications

    Institute of Scientific and Technical Information of China (English)

    董子尧; 李昕

    2012-01-01

    Electrochromic material is one of the most promising intelligent materials due to its controllable structure, rich color, low cost and energy. The structure and mechanism of electrochromic device are summarized, and the progress of each layer material (transparent conductor, electrochromic, electrolyte, ion storage) is emphatically introduced. Besides, several important applications of electrochromic devices are listed in detail, taking smart windows, auto dimming rearview mirror, electronic paper, sensors, military camouflage for example.%电致变色材料具有结构可控、色彩丰富、成本低廉、节能低耗等特点,是目前最具应用前景的智能材料之一.概述了电致变色器件的基本结构、变色机理,着重介绍了电致变色器件各层材料(透明导电层、电致变色层、电解质层、离子储存层)的特性要求及研究现状,举例说明了其在智能窗、防眩目汽车后视镜、电子纸、传感器、军事伪装中的应用.

  14. 氧化锆牙科材料改性研究进展%Research Progress in Modification of Dental Zirconia Materials

    Institute of Scientific and Technical Information of China (English)

    朱香利; 方建强; 肖遂

    2015-01-01

    Zirconia ceramics were widely used as dental restorative materials due to its excellent biocompatibility, high strength, toughness and aesthetic. The purpose of this paper was to summary the research progress of the pigmentation and toughness of dental zirconia and zirconia-based bioactive materials in the field of prosthodontics. And also it prospected the future research and development of new zirconia based materials for dental application.%氧化锆因具良好的生物相容性、较高的强度、韧性以及美观效果,被广泛地用作牙科修复材料。随着科学技术的不断发展,氧化锆用于牙科修复材料的研究也有了较大的进展。该文从氧化锆增韧、氧化锆着色和氧化锆基生物活性材料3个方面概述了氧化锆作为牙科修复材料的研究进展,并对其做了进一步展望。

  15. Progress in nano-electro optics characterization of nano-optical materials and optical near-field interactions

    CERN Document Server

    Ohtsu, Motoichi

    2005-01-01

    This volume focuses on the characterization of nano-optical materials and optical-near field interactions. It begins with the techniques for characterizing the magneto-optical Kerr effect and continues with methods to determine structural and optical properties in high-quality quantum wires with high spatial uniformity. Further topics include: near-field luminescence mapping in InGaN/GaN single quantum well structures in order to interpret the recombination mechanism in InGaN-based nano-structures; and theoretical treatment of the optical near field and optical near-field interactions, providing the basis for investigating the signal transport and associated dissipation in nano-optical devices. Taken as a whole, this overview will be a valuable resource for engineers and scientists working in the field of nano-electro-optics.

  16. PVA可生物降解材料研究进展%Research Progress in Polyvinyl Alcohol Biodegradable Material

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 李东立; 许文才; 付亚波

    2014-01-01

    聚乙烯醇是一种可生物降解、水溶性的聚合物,具有生物相容性能优良、易成膜、制备工艺相对简单等特点,在包装领域得到广泛应用。简述了聚乙烯醇的性能特点、降解机理、影响降解机理的各种因素;综述了淀粉、改性淀粉、壳聚糖、聚乳酸改性聚乙烯醇( PVA)制备可生物降解材料的方法与研究成果,对聚乙烯醇的研究成果进行了分析,指出低成本、力学性能优良、降解完全的PVA可生物降解改性薄膜将是今后的研究重点;聚乙烯醇/纳米黏土改性高阻隔包装材料也是主要的研究方向。%Polyvinyl alcohol ( PVA) is a biodegradable, water-soluble polymer which has excellent biocompatibility, easy film formation properties and relatively simple preparation and it has been widely used in packaging area. This paper describes the performance characteristics of polyvinyl alcohol, degradation mechanism, the various factors affecting the degradation mechanism of polyvinyl alcohol and summarizes the preparation method and research results of polyvinyl alcohol ( PVA) biode-gradable material which modified by starch, modified starch, chitosan, polylactic acid. In the end, it indicates that PVA bi-odegradable film of low cost, excellent mechanical properties and completely biodegradable film is the research priorities. Also, the PVA/nanoclay high barrier packaging materials is the main point for research.

  17. Band parameters of phosphorene

    DEFF Research Database (Denmark)

    Lew Yan Voon, L. C.; Wang, J.; Zhang, Y.;

    2015-01-01

    Phosphorene is a two-dimensional nanomaterial with a direct band-gap at the Brillouin zone center. In this paper, we present a recently derived effective-mass theory of the band structure in the presence of strain and electric field, based upon group theory. Band parameters for this theory are co...

  18. Flat Band Quastiperiodic Lattices

    Science.gov (United States)

    Bodyfelt, Joshua; Flach, Sergej; Danieli, Carlo

    2014-03-01

    Translationally invariant lattices with flat bands (FB) in their band structure possess irreducible compact localized flat band states, which can be understood through local rotation to a Fano structure. We present extension of these quasi-1D FB structures under incommensurate lattices, reporting on the FB effects to the Metal-Insulator Transition.

  19. Density of States for Warped Energy Bands

    Science.gov (United States)

    Mecholsky, Nicholas A.; Resca, Lorenzo; Pegg, Ian L.; Fornari, Marco

    2016-02-01

    Warping of energy bands can affect the density of states (DOS) in ways that can be large or subtle. Despite their potential for significant practical impacts on materials properties, these effects have not been rigorously demonstrated previously. Here we rectify this using an angular effective mass formalism that we have developed. To clarify the often confusing terminology in this field, “band warping” is precisely defined as pertaining to any multivariate energy function E(k) that does not admit a second-order differential at an isolated critical point in k-space, which we clearly distinguish from band non-parabolicity. We further describe band “corrugation” as a qualitative form of band warping that increasingly deviates from being twice differentiable at an isolated critical point. These features affect the density-of-states and other parameters ascribed to band warping in various ways. We demonstrate these effects, providing explicit calculations of DOS and their effective masses for warped energy dispersions originally derived by Kittel and others. Other physical and mathematical examples are provided to demonstrate fundamental distinctions that must be drawn between DOS contributions that originate from band warping and contributions that derive from band non-parabolicity. For some non-degenerate bands in thermoelectric materials, this may have profound consequences of practical interest.

  20. SINGLE CRYSTAL GROWTH, X-RAY STRUCTURE ANALYSIS, OPTICAL BAND GAP, RAMAN SPECTRA, STRAIN TENSOR AND PHOTOLUMINSCENCE PROPERTIES IN [HgCl4]- [R]+ AND [ZnCl4]- [R]+ (R = 2-AMINO-5-CHLOROPYRIDINE HYBRID MATERIALS

    Directory of Open Access Journals (Sweden)

    A. Kumar

    2015-09-01

    Full Text Available The single crystal growth  of tetrachloromercurate (II [HM-1] and tetrachlorozincate (II [HM-2] with 2-amino-5-chloropyridine has been performed by slow cooling (SC crystal growth technique of solution growth methodin which needle shaped transparent single crystals (0.5 x 0.2 x 0.2mm were obtained. The crystal structures of these hybrid materials have been studied by X-ray diffraction, experimental and computational methods. [HgCl4]2- anions have a distorted tetrahedral geometry and the tetrahedra hybrid structure exhibit interwoven inorganic-organic layers mingled through N-Hδ+...Clδ- hydrogen bonding interactions. The mercurophilic interactions [Hg...Hg = 3.984(5Å] and halogen interactions [Cl...Cl = 3.406(2Å] form 2D parallelogram pattern of secondary interactions in [HM-1] whereas for [HM-2] crystal structure is stabilized by Cl...Cl = 3.357(2Å interactions. UV-vis absorption spectra depict the change in optical band gap from 3.01 eV to 3.42 eV on replacing the metal halide group, could be due to increase in optical absorption as a function of wavelength. The Raman and Hyper-Raman tensors calculations were performed based on single crystal X-ray data and the Lagrangian strain tensor calculations show the degree of lattice distortion = 1.794 between [HM-1] and [HM-2] which are useful tools for the optical response properties of inorganic-organic hybrid derivatives. The photoluminescence emission spectra peaks were observed in the wavelength range of 371 to 598 nm for material [HM-1] and  in the wavelength range of 384 to 600 nm for material [HM-2] and lie in the visible range for both materials.

  1. Research Progress of Biomimetic Material Prepared by Bacterial Cellulose%细菌纤维素制备生物医用材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    蔡锐波; 陈海宏; 陈向标

    2012-01-01

    Bacterial cellulose(BC) is a potential versatile biomaterial. Research progress of medical dressing, vascular prosthesis and artificial skeleton prepared by bacterial cellulose were introduced at home and abroad. In addition, the hot spots and the main development direction of bacterial cellulose composite biomimetic materials were discussed.%细菌纤维素是一种很有潜力的新型生物纤维材料.重点介绍了国内外关于细菌纤维素在制备医用敷料、人造血管及人造骨骼等医用材料方面的研究进展,并指出今后的研究热点及主要发展方向.

  2. [The role of zooplankton and micronektron in the cycling and remineralization of chemical materials in the Southern California Bight: Progress report, November 1985-June 1986

    International Nuclear Information System (INIS)

    A Progress Report on Grant FG05-85ER60340 has already been submitted to DOE, and is appended here. The appended report covers much of the work completed during the current contract period. Work on the just-completed May 1986 cruise samples is just beginning at the time of writing. Sediment traps deployed at two locations in Santa Monica Basin in October 1985 were recovered in February 1986. The traps have sequentially rotating cups set to collect material for 14 days each during the deployment period. We have finished radiochemical analyses on the sediment trap samples collected on the February 1986 Cruise. Pellet production rates for salps and euphausiids were reported earlier. The February cruise was principally a hydrographic and trap recovery cruise, and there was no time for pellet production rate experiments. Thus, all the February hauls are being analyzed to assess diel biomass estimates of selected size classes of zooplankton in the vicinity of the traps. 5 tabs

  3. 多孔钛的研究进展%Progress in Research and Development of Porous Titanium Materials

    Institute of Scientific and Technical Information of China (English)

    汤慧萍; 王建

    2014-01-01

    Porous titanium has evolved into an important class of metallic materials and is the choice of material for many industrial applications,and the R&D activities on porous titanium have shown a strong uptrend in recent years.This paper begins by providing a brief review of the history of porous titanium and then discusses the preparation processes and char-acteristics of porous titanium materials.The permeability,mechanical property and corrosion behavior of porous titanium are reviewed subsequently,followed by selected examples of their commercial applications.The properties of porous titani-um are mainly determined by the pore structure.Using different techniques,porous titanium with uniform,bimodal,gra-dient,honeycomb or closed pore structures can be produced.In addition,similar to the fabrication of dense titanium mate-rials,the interstitial impurities (O,N and C)in porous titanium should be strictly controlled for both desired mechanical properties and corrosion resistance.Additive manufacturing or 3D metal printing provides a powerful platform for the design and fabrication of novel porous titanium structures compared to conventional powder metallurgy.Future developments of porous titanium will continue to be driven by applications but the new design freedom offered by additive manufacturing is expected to play an increasingly important role.%作为结构功能一体化材料,多孔钛在众多工业领域具有广泛的应用前景,已成为近年来十分活跃的研究方向。简要回顾了多孔钛的研究历史,重点介绍了多孔钛的制备方法与孔结构,并对多孔钛的渗透性能、力学性能和耐腐蚀性能以及主要的商业应用进行了介绍。众多研究和应用表明,多孔钛的性能与功能强烈依赖于孔结构,不同方法制备多孔钛的孔结构可以归纳为均一孔结构、双峰孔结构、梯度孔结构、蜂窝结构和闭孔结构5种类型。除孔结构外,与致密钛合金一样,多

  4. Research Progress of Prosthetic Disc Nucleus Materials%人工髓核假体材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    高玲娣; 娄彤; 黄菊英

    2013-01-01

    髓核摘除是治疗腰椎间盘突出症的传统手术方法,但会导致患者术后腰椎承载力不均,而人工髓核假体的出现为腰椎间盘突出症的治疗带来了新的思考方向。本文对人工髓核假体材料的类型、特点及存在的问题进行了阐述,期待人工髓核植入技术能够为腰椎间盘突出患者带来福音。%The postoperative bearing capacity of lumbar vertebrae will be uneven with removal of nucleus pulposus, which is one of the traditional surgical methods for protrusion of lumbar intervertebral disc. However, the development of prosthetic disc nucleus provides a new direction for the therapy of protrusion of lumbar intervertebral disc. This paper discusses the types, characteristics and existing problems of prosthetic disc nucleus materials to expect that prosthetic disc nucleus implantation can improve the health condition of patients with protrusion of lumbar intervertebral disc.

  5. Technical Division quarterly progress report, October 1--December 31, 1977. [Fuel cycle research and development; special materials production

    Energy Technology Data Exchange (ETDEWEB)

    Slansky, C.M. (ed.)

    1978-02-01

    Results are presented on the fluidized-bed calcination of simulated radioactive waste from the reprocessing of spent commercial nuclear fuel and on the removal of actinide elements from the waste prior to calcination. Other programs include the development of storage technology for /sup 85/Kr waste; and the behavior of volatile radionuclides during the combustion of HTGR graphite-based fuel. The long-term management of defense waste from the ICPP covers post-calcination treatment of ICPP calcined waste; the removal of actinide elements from first-cycle raffinate; the retrieval and handling of calcined waste from ICPP storage vaults; and the preparation of the Programmatic Environmental Impact Statement on ICPP waste. Process improvements are reported on the Fluorinel headend process for Zircaloy-clad fuels and on uranium accountability measurements. Other development results cover the process for recovering spent Rover fuel, buried pipeline transfer systems, support to the Waste Management Program, Waste Calcining Facility support, New Waste Calcining Facility support, and effluent monitoring methods evaluation and development. In this category are studies on nuclear materials security, application of a liquid-solid fluidized-bed heat exchanger to the recovery of geothermal heat, inplant reactor source term measurements, burnup methods for fast breeder reactor fuels, absolute thermal fission yield measurements, analytical support to light water breeder reactor development, research on analytical methods, and the behavior of environmental species of iodine.

  6. Progress on femtosecond laser-based system-materials: three-dimensional monolithic electrostatic micro-actuator for optomechanics

    Science.gov (United States)

    Yang, Tao; Bellouard, Yves

    2016-03-01

    Femtosecond laser-dielectric interaction in a three-dimensional (3D) manner defines a capable platform for integrated 3D micro-devices fabricated out of a single piece of system-material. Here, we add a new function to femtosecond laserbased single monolith in amorphous fused silica by demonstrating a transparent 3D micro-actuator using non-ablative femtosecond laser micromachining with subsequent chemical etching. The actuation principle is based on dielectrophoresis (DEP), defined as the unbalanced electrostatic action on dielectrics, due to an induced dipole moment under a non-uniform electric field. An analytical model of this actuation scheme is proposed, which is capable of performance prediction, design parameter optimization and motion instability analysis. Furthermore, the static and dynamic performances are experimentally characterized using optical measurement methods. An actuation range of 30 μm is well attainable; resonances and the settling time in transient responses are measured; the quality factor and the bandwidth for the primary vertical resonance are also evaluated. Experimental results are in good consistence with theoretical analyses. The proposed actuation principle suppresses the need for electrodes on the mobile, non-conductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of femtosecond laser manufacturing process, this actuation scheme can be integrated in other functionalities within monolithic transparent Micro-Electro-Mechanical Systems (MEMS) for applications like resonators, adaptive lenses and integrated photonics circuits.

  7. Current progress in ternary LREBa{sub 2}Cu{sub 3}O{sub y} materials and their application

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M. [Superconductivity Research Laboratory, International Superconductivity Technology Center, Shinonome 1-10-13, Koto-Ku, Tokyo 135-0062 (Japan)], E-mail: miryala1@istec.or.jp; Jirsa, M. [Institute of Physics, ASCR, CZ-182 21 Praha 8 (Czech Republic); Sakai, N. [Superconductivity Research Laboratory, International Superconductivity Technology Center, Shinonome 1-10-13, Koto-Ku, Tokyo 135-0062 (Japan); Murakami, M. [Shibaura Institute of Technology, Shibaura 3-9-14, Minato-ku, Tokyo 108-8548 (Japan); Hirabayashi, I. [Superconductivity Research Laboratory, International Superconductivity Technology Center, Shinonome 1-10-13, Koto-Ku, Tokyo 135-0062 (Japan)

    2008-06-15

    The J{sub c} and H{sub irr} values at 77 K of ternary light-rare-earth compounds, LREBa{sub 2}Cu{sub 3}O{sub y} 'LRE-123', are usually high enough to serve in various applications. Several sources of vortex pinning can be in these composites tailored to fit the needs of the particular application. The list comprises LRE/Ba solid solution, oxygen vacancies, large particles of secondary phases, twin planes, nanoscale lamellas, etc. By means of the latter defects one can achieve a very high irreversibility field. Refinement of secondary phase particles and the optimal choice of their amount enhance the electromagnetic performance in a broad temperature range, up vicinity of T{sub c}, allowing levitation at liquid oxygen, 90.2 K. An optimum content of MoO{sub 3} doubles the self-field super-current at 77 K, H||c-axis. Altogether, the pinning tailoring in ternary LRE-123 materials provides a flexible and reliable way to fit the electromagnetic performance with the needs of sophisticated high-temperature and high-magnetic-field applications.

  8. 宽频高性能短切碳纤维/聚氨酯泡沫吸波材料制备∗%Study onwide-band wave-absorbing foam material prepared by shortened carbon fiber and polyurethane

    Institute of Scientific and Technical Information of China (English)

    贺龙辉; 胡照文; 邓联文; 黄生祥; 刘胜; 贺君; 文瑞

    2015-01-01

    采用两种不同长度的短切碳纤维做填充吸收剂制备聚氨酯硬质泡沫基复合吸波材料,使用微波矢量网络分析仪系统和弓形法测量该类复合材料的微波吸收性能,研究了两种不同长度的短切碳纤维单独应用以及复合应用时,填充质量分数、混合填充比、总填充量以及匹配层对聚氨酯泡沫吸波复合材料在8~18 GHz 频段吸波性能的影响.结果表明,短切碳纤维的最佳填充质量分数为7%,短切碳纤维 T 1和 T 2的最佳混合填充比为3∶4;匹配层引入可进一步改善 X 波段和 Ku 波段的宽频吸波性能,在 X 波段和 Ku 波段可实现全频段优于-10 dB 的吸波性能,峰值达-21.1 dB.%The preparation of polyurethane rigid foam-based composite wave-absorbing material filling with two kinds of shortened carbon fibers with different lengths,microwave-absorbing properties of material were meas-ured by microwave vector network analyzer measuring system and the arch method,to study the filling mass fraction,mixed filling rate and total filling amount of two kinds of shortened carbon fibers with different lengths when used alone and mixedly and the matching layer on the influence of wave-absorbing properties of polyurethane foam-based composite material in the range of 8-18 GHz.The results show that the optimum fill-ing mass fraction of shortened carbon fibers was 7%,the best mixed filling rate of shortened carbon fibers T 1 and T 2 was 3∶4;the matching layer introduced to further improve wave-absorbing performance in the X-band and the Ku-band frequency ranges,the reflection loss can achieve better than -10 dB,and the peak value was-21.1 dB.

  9. Research progress on shape-memory polyurethane materials%形状记忆聚氨酯材料的进展

    Institute of Scientific and Technical Information of China (English)

    郑广鹏

    2011-01-01

    The latest research progress on shape memory polyurethane materials both at home and abroad is reviewed, including chain segment optimization design, doped compounding with various inorganic nano materials, crosslinking and supramo-lecular network modification, et al. Different modification methods are involved to get better shape fixed rate, deformation recovery rate, precise shape memory temperature, heat resistance and mechanical strength, and biological adaptability as well. The application status and prospect of shape memory polyurethane in the fields of medicine, textile and others in recent years are reviewed.%国内外形状记忆聚氨酯材料在性能改进上的最新进展,包括链段上的优化设计,与各种无机纳米材料的掺杂复合,交联和超分子网络化改性等.各种改性方法皆在获得更佳形状固定率、形变回复率、精确的形状记忆温度、材料的耐热性和力学强度以及生物适应性等性能.近几年,形状记忆聚氨酯在医学领域、纺织领域以及其它相关领域均获得新的应用和进展.

  10. Optical transmission performance of transparent spinel ceramic wide band window materials%宽波段窗口材料透明尖晶石的透过性能

    Institute of Scientific and Technical Information of China (English)

    雷牧云; 李祯; 洪冬梅; 赵艳民; 娄载亮

    2012-01-01

    Abstract: Transparent spinel ceramic (TMAC) with high transmittance in the ultraviolet, visible, middle infrared and microwave regions is an excellent wide band windows material, and can meet the development of photoelectric system for its thermostability, anticorrosion, and high hardress and mechanical strength, which provide broad application prospect. Researches of TMAC prepared by hot pressing (HP) and hot isostatic pressing (HIP) technology were introduced. AR-coating was used to improve the transmittance of TMAC in visible and infrared regions. The infrared transmittance with different incident angles were tested, and different AR-coating with different incident angles were coated. The transmittance in millimeter-wave band was tested and simulated. And the lacks and future research of TMAC material were also discussed in the end.%透明尖晶石陶瓷(TMAC)材料具有耐高温、耐腐蚀、较高的硬度和机械强度等优点,透过波段从紫外、可见、中波红外到微波,是性能优异的宽波段窗口材料,能够满足不断发展的光电系统对窗口材料的多重要求,且有广阔的应用前景.对采用热压烧结结合热等静压工艺制备出的TMAC材料进行了透过性能研究,分别对可见和红外波段镀制了增透膜,测试了不同入射角的红外透过率,并根据入射角的不同镀制了增透膜,测试了镀制金刚石膜后的透过率,并对毫米波波段的透过率做了初步测试和仿真,分析了不足和未来的研究方向.

  11. Band Interaction between Chiral Doublet Bands

    Institute of Scientific and Technical Information of China (English)

    QI Bin; ZHANG Shuang-Quan; WANG Shou-Yu; MENG Jie

    2010-01-01

    @@ Band interaction between the chiral doublet bands based on πh11/2(×) vh-111/2 configuration is investigated in the particle rotor model with different triaxial deformation γ. The variation of chiral partner states with γvalues is understood qualitatively based on the basic picture of two interaction levels, which is confirmed further by the calculated overlap integral of wave functions at different γ values. It is found that the interaction strengths ofchiral partner states are obvionsly different for odd spins and even ones.

  12. Dynamical screening effects in correlated electron materials-a progress report on combined many-body perturbation and dynamical mean field theory: 'GW + DMFT'.

    Science.gov (United States)

    Biermann, Silke

    2014-04-30

    We give a summary of recent progress in the field of electronic structure calculations for materials with strong electronic Coulomb correlations. The discussion focuses on developments beyond the by now well established combination of density functional and dynamical mean field theory dubbed 'LDA + DMFT'. It is organized around the description of dynamical screening effects in the solid. Indeed, screening in the solid gives rise to dynamical local Coulomb interactions U(ω) (Aryasetiawan et al 2004 Phys. Rev. B 70 195104), and this frequency dependence leads to effects that cannot be neglected in a truly first principles description. We review the recently introduced extension of LDA + DMFT to dynamical local Coulomb interactions 'LDA + U(ω) + DMFT' (Casula et al 2012 Phys. Rev. B 85 035115, Werner et al 2012 Nature Phys. 1745-2481). A reliable description of dynamical screening effects is also a central ingredient of the 'GW + DMFT' scheme (Biermann et al 2003 Phys. Rev. Lett. 90 086402), a combination of many-body perturbation theory in Hedin's GW approximation and dynamical mean field theory. Recently, the first GW + DMFT calculations including dynamical screening effects for real materials have been achieved, with applications to SrV O3 (Tomczak et al 2012 Europhys. Lett. 100 67001, Tomczak et al Phys. Rev. B submitted (available electronically as arXiv:1312.7546)) and adatom systems on surfaces (Hansmann et al 2013 Phys. Rev. Lett. 110 166401). We review these and comment on further perspectives in the field. This review is an attempt to put elements of the original works into the broad perspective of the development of truly first principles techniques for correlated electron materials. PMID:24722486

  13. Development of polyimide materials for use in solar energy systems. Semi-annual technical progress report, August 1, 1978-January 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Wilcoxson, A.L.; Sorathia, U.A.; Gagliani, J.

    1979-01-01

    This report covers six months of effort on a program to optimize and characterize improved insulation materials for solar energy systems. Two separate and distinct products have been studied, a lightweight flexible insulating foam and a high density, rigid, load bearing insulating foam. These products are derived from a polyimide resin, the formulations and processes for which were developed under NASA-JSC sponsored programs. These materials are non-burning and do not emit measurable quantities of smoke or toxic byproducts. Candidate resins were selected on the basis of cost, expected foam insulating and weatherability properties and ease of production. A critical characterization criteria was established in the form of environmental exposure resistance. The foams were evaluated on the basis of this direct exposure test. Studies initiated to improve the resistance included additive studies, using reinforcements and uv absorbers, and postcure studies. The various formulations were also screened on the basis of humidity resistance. On the basis of testing conducted, four different resin formulations at a foam density of approximately 16 kg/m/sup 3/ (1.0 PCF) are meeting minimum requirements. Candidate selection is still in progress. The rigid foam was optimized through a glass reinforcement study and a process parameter study. This work was characterized on the basis of low cost, ease of production, and the critical property requirement of compressive strength. The result of these studies was an optimized glass strand/microballoon reinforced foam which meets the tested property goals at a density of approximately 240 kg/m/sup 3/ (15.0 PCF). This candidate material is under advanced testing.

  14. Research Progress in Cellulose-based Absorbent Material%纤维素系吸水材料的研究现状及发展前景

    Institute of Scientific and Technical Information of China (English)

    高桂林; 沈葵忠; 房桂干; 邓拥军; 李萍; 金莉; 别士霞

    2012-01-01

    This review addressed recent progress in cellulose-based absorbent materials preparation and application Firstly, absorbent material produced directly from native cellulose (including bacterial cellulose) via cellulose dissolution are introduced. Secondly, cellulose highly absorbing polymer based on its derivatives which were obtained by physical as well as chemical cross-linking strategies was discussed. Thirdly, composite prepared by using cellulose in conjunction with other polymers through blending, formation of polyelectrolyte complexes, and interpenetrating polymer networks (IPNs) technology was addressed . Finally, cellulose-inorganic hybrid hydrogel prepared by embedding inorganic nano-partieles in cellulose matrices was described. In addition,the prospect of cellulosic absorbent materials and some problems still needed to be solved were summarized.%本文回顾了近年来纤维素系吸水材料的制备方法及其应用,具体介绍了纤维素系吸水材料的几种主要制备方法:一是直接对天然纤维素进行处理来制备;第二是利用纤维素衍生物通过物理或化学交联的方法制备;第三是将纤维素与其他聚合物进行反应形成复合树脂或聚电解质配合物,还可以采用互穿聚合网络技术进行处理;另外将无机纳米粒子嵌入纤维素矩阵中也可以制备纤维素-无机混合凝胶树脂。最后还对纤维素系高吸水材料的发展前景以及仍需解决的问题进行了总结。

  15. 药物控释载体材料的研究与应用%Application and progress in the materials for drug controlled release

    Institute of Scientific and Technical Information of China (English)

    王洪新; 陈晓明

    2011-01-01

    背景:作为控制释放体系的药物载体材料大多是高分子材料,但部分纳米无机材料也正逐步应用到药物控释材料体系中并取得了很好的研究成果.因此,药物控释用载体材料的设计与研究应用越来越受到重视.目的:对国内外药物控释载体材料的应用及最新研究进展作一综述.方法:应用计算机检索CNKI和Elsevier SD 数据库中1999-01/2011-01 关于药物控缓释材料的文章,在标题和摘要中以"高分子,介孔材料,无机硅,磷酸盐,控释"或"polymer,mesoporous materials,Inorganic s ilicon,calcium phosphate,controlled release"为检索词进行检索.选择文章内容与药物控缓释有关者,同一领域文献则选择近期发表或发表在权威杂志文章.纳入25 篇文献进行综述.结果与结论:药物控缓释载体材料以用药量小、作用时间长、靶向作用好等特点被广泛关注,但是仍存在载药后药物失活,丧失生物活性等缺陷,目前随着复合药物载体材料和经皮给药装置研究的发展,控缓释材料在临床治疗中的应用必将更加广泛.%BACKGROUND: Polymer materials play an important role in drug controlled release system. But nano-inorganic materials are studied as a new drug and gene controlled delivery carrier and appears to be very promising, so more considered are paied attention to the design and research of drug controlled release carrier materials.OBJECTIVE: To summarize the applications and research progress of drug controlled release materials.METHODS: Database of CNKI and Elsevier SD (1999-01/2011-01) were retrieved to search the related articles about the materials for drug controlled release using the keywords of “polymer, mesoporous materials, inorganic silicon, calcium phosphate,controlled release” in Chinese and English. Finally, 25 articles were included in review analysis.RESULTS AND CONCLUSION: Drug controlled release carrier materials are widely drawn by their low dosage, long

  16. One-man band

    OpenAIRE

    Stillman, R.

    2013-01-01

    This website presents practice-based research related to solo simultaneous instrumental performance ('one-man band'). The site was conceived as a creative and widely accessible platform for music and ideas resulting from one-man band activates carried out between 2008 and 2013. Central to this project is an interest in how one-man band technique informs compositional process, including studio production. Through presentation and analysis of the author’s own creative practice, the site exp...

  17. Development of the Shear Bands in Saturated Soil

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper describes the development of shear bands in saturated soil under simple shear using a matching technique at the moving boundary of a shear band, and it is shown that the development of shear bands is affected by the coupling strain rate and pore pressure of material. Some numerical solutions have been presented.

  18. US/Japan collaborative program on fusion reactor materials: Summary of the tenth DOE/JAERI Annex I technical progress meeting on neutron irradiation effects in first wall and blanket structural materials

    International Nuclear Information System (INIS)

    This meeting was held at Oak Ridge National Laboratory on March 17, 1989, to review the technical progress on the collaborative DOE/JAERI program on fusion reactor materials. The purpose of the program is to determine the effects of neutron irradiation on the mechanical behavior and dimensional stability of US and Japanese austenitic stainless steels. Phase I of the program focused on the effects of high concentrations of helium on the tensile, fatigue, and swelling properties of both US and Japanese alloys. In Phase II of the program, spectral and isotropic tailoring techniques are fully utilized to reproduce the helium:dpa ratio typical of the fusion environment. The Phase II program hinges on a restart of the High Flux Isotope Reactor by mid-1989. Eight target position capsules and two RB* position capsules have been assembled. The target capsule experiments will address issues relating to the performance of austenitic steels at high damage levels including an assessment of the performance of a variety of weld materials. The RB* capsules will provide a unique and important set of data on the behavior of austenitic steels irradiated under conditions which reproduce the damage rate, dose, temperature, and helium generation rate expected in the first wall and blanket structure of the International Thermonuclear Experimental Reactor

  19. 轻水反应堆(LWR)用包壳材料研究进展%Research Progress on Cladding Materials Used for Light Water Reactor

    Institute of Scientific and Technical Information of China (English)

    周军; 李中奎

    2014-01-01

    Light water reactor(LWR)is a major type of nuclear power reactor in the world.Because of low neutron ab-sorption,good corrosion resistance,and good mechanical properties,zirconium alloys are the key structural materials and functional materials for LWR power used as the cladding materials of fuel elements and other structural materials.With the development of nuclear power technology,the higher performances of the cladding material are needed,this paper reviews the research and application progress of nuclear zirconium alloy cladding and the research and development of new SiC cladding materials.In general,zirconium alloys are still the main structural materials in nuclear reactor in the coming decades,continuous R&D and improved performance of new zirconium alloys are a common goal of researchers around the world;it is necessary to increase investments and strengthen the support with human resources and financial input in order to accelerate the pace of industrialization of zirconium alloys with Chinese independent intellectual property rights;with higher melting point and better corrosion resistance requirement,SiC is a potential material for cladding of fourth genera-tion nuclear reactor,but also needs to invest a lot of research.%轻水反应堆(LWR)是国际上多数核电站采用的堆型。锆具有良好的加工性能,优良的机械性能,较高的熔点、优异的耐蚀性能及核性能,被用作燃料包壳和堆芯结构材料,是发展核电及核动力舰船不可替代的关键结构材料和功能材料。随着核电技术的发展,对堆芯包壳材料性能提出了更高的要求,综述了核用锆合金包壳材料的国内外研究和使用现状以及新型SiC包壳材料的研发现状。总体来说,锆合金在未来几十年内仍是核反应堆包壳材料的主要用材,开展新合金的研发,不断提升锆合金的性能是世界各国研究者共同的目标;适时加大投入力度,

  20. Recent progress of sulfur composites as cathode materials for lithium sulfur batteries%锂硫电池正极复合材料研究现状

    Institute of Scientific and Technical Information of China (English)

    杨蓉; 邓坤发; 刘晓艳; 曲冶; 雷京; 任冰

    2015-01-01

    锂硫电池由于其高理论能量密度(2600W·h/kg)而受到了广泛的关注,是极具应用前景的电池体系。硫基正极材料作为锂硫电池的重要组成部分,是提高电池性能的关键。然而锂硫电池还存在一些问题,如硫的利用率低及正极结构的稳定性差等。本文综述了近几年锂硫电池硫正极复合材料的研究现状,分别从硫/碳复合、硫/导电聚合物复合、硫/氧化物复合3个方面进行介绍,指出了未来锂硫电池正极材料要注意结合硫/导电聚合物及硫/氧化物的优势并注重材料结构的设计,向核壳或类核壳结构方向发展的趋势,同时还要提高载硫量,提高循环稳定性,以获得高性能的锂硫电池。%As a promising battery system,lithium-sulfur battery with high theoretical energy density (2600W·h/kg) has attracted great attention. As one of the essential ingredients for lithium-sulfur batteries,sulfur cathode material is the key to improve the performance of batteries. However,there are some serious and unavoidable problems for lithium-sulfur battery,such as low utilization efficiency of sulfur in cathode and poor stability of electrode structure. In this review,the recent progress of sulfur composites as cathode materials for lithium-sulfur batteries is introduced. Cathode materials are divided into three kinds of composites,such as sulfur/carbon,sulfur/polymer and sulfur/oxide composite materials,which are discussed respectively. It is pointed out that the coming development of cathode materials for lithium-sulfur batteries should be focused on the combination of advantages of sulfur/polymer and sulfur/oxide composite materials,and the design of material structure,such as core-shell or core-shell-like structure for cathode materials. At the same time,high sulfur loading and high cycle stability will be good for the performance improvement of lithium-sulfur batteries.

  1. 锂硫电池正极复合材料研究现状%Recent progress of sulfur composites as cathode materials for lithium sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    杨蓉; 邓坤发; 刘晓艳; 曲冶; 雷京; 任冰

    2015-01-01

    As a promising battery system,lithium-sulfur battery with high theoretical energy density (2600W·h/kg) has attracted great attention. As one of the essential ingredients for lithium-sulfur batteries,sulfur cathode material is the key to improve the performance of batteries. However,there are some serious and unavoidable problems for lithium-sulfur battery,such as low utilization efficiency of sulfur in cathode and poor stability of electrode structure. In this review,the recent progress of sulfur composites as cathode materials for lithium-sulfur batteries is introduced. Cathode materials are divided into three kinds of composites,such as sulfur/carbon,sulfur/polymer and sulfur/oxide composite materials,which are discussed respectively. It is pointed out that the coming development of cathode materials for lithium-sulfur batteries should be focused on the combination of advantages of sulfur/polymer and sulfur/oxide composite materials,and the design of material structure,such as core-shell or core-shell-like structure for cathode materials. At the same time,high sulfur loading and high cycle stability will be good for the performance improvement of lithium-sulfur batteries.%锂硫电池由于其高理论能量密度(2600W·h/kg)而受到了广泛的关注,是极具应用前景的电池体系。硫基正极材料作为锂硫电池的重要组成部分,是提高电池性能的关键。然而锂硫电池还存在一些问题,如硫的利用率低及正极结构的稳定性差等。本文综述了近几年锂硫电池硫正极复合材料的研究现状,分别从硫/碳复合、硫/导电聚合物复合、硫/氧化物复合3个方面进行介绍,指出了未来锂硫电池正极材料要注意结合硫/导电聚合物及硫/氧化物的优势并注重材料结构的设计,向核壳或类核壳结构方向发展的趋势,同时还要提高载硫量,提高循环稳定性,以获得高性能的锂硫电池。

  2. Phononic band gap structures as optimal designs

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2003-01-01

    In this paper we use topology optimization to design phononic band gap structures. We consider 2D structures subjected to periodic loading and obtain the distribution of two materials with high contrast in material properties that gives the minimal vibrational response of the structure. Both in-plane...... and out-of-plane vibrations are considered....

  3. Photonic band gap in thin wire metamaterials.

    Science.gov (United States)

    Hock, Kai Meng

    2008-03-01

    We investigate the band structure of a class of photonic crystals made from only thin wires. Using a different method, we demonstrate that a complete photonic band gap is possible for such materials. Band gap materials normally consist of space filling dielectric or metal, whereas thin wires occupy a very small fraction of the volume. We show that this is related to the large increase in scattering at the Brillouin zone boundary. The method we developed brings together the calculation techniques in three different fields. The first is the calculation of scattering from periodic, tilted antennas, which we improve upon. The second is the standard technique for frequency selective surface design. The third is obtained directly from low energy electron diffraction theory. Good agreements with experiments for left handed materials, negative materials, and frequency selective surfaces are demonstrated.

  4. ZEBRAFISH CHROMOSOME-BANDING

    NARCIS (Netherlands)

    PIJNACKER, LP; FERWERDA, MA

    1995-01-01

    Banding techniques were carried out on metaphase chromosomes of zebrafish (Danio rerio) embryos. The karyotypes with the longest chromosomes consist of 12 metacentrics, 26 submetacentrics, and 12 subtelocentrics (2n = 50). All centromeres are C-band positive. Eight chromosomes have a pericentric C-b

  5. Stretch Band Exercise Program

    Science.gov (United States)

    Skirka, Nicholas; Hume, Donald

    2007-01-01

    This article discusses how to use stretch bands for improving total body fitness and quality of life. A stretch band exercise program offers a versatile and inexpensive option to motivate participants to exercise. The authors suggest practical exercises that can be used in physical education to improve or maintain muscular strength and endurance,…

  6. Multiple band circularly polarized microstrip antenna

    Science.gov (United States)

    Yu, I. P. (Inventor)

    1980-01-01

    A multiple antenna assembly for communicating electromagnetic radiation is disclosed. An antenna element stack is constructed of a plurality of elliptical lamina antenna elements mutally separated by layers of dielectric material, and separated from a ground plane by dielectric material. The antenna assembly is coupled through a feed line in contact with the top antenna element. A conductor joins the remaining antenna elements to the ground plane. Each individual antenna element is operable for communication reception and transmission within a frequency band determined by the size of the particular antenna element. The sizes of the antenna elements may be selected to provide electromagnetic radiation communication over several distinct frequency bands, or to connect the individual bands into a broad band.

  7. 聚丙烯改性料在现代汽车中的应用及研究进展%Application and Research Progress of Modified Polypropylene Material in Modern Cars

    Institute of Scientific and Technical Information of China (English)

    余中云; 孙亚楠

    2013-01-01

    分析了聚丙烯改性料在汽车工业中应用的优势,综合概述了汽车零部件用聚丙烯改性料的研究进展.%In this paper,the advantage was analyzed of modified polypropylene material application in automobile industry.And the research progresses of modified polypropylene material used in automobile parts were reviewed.

  8. Tulane/Xavier University Hazardous Materials in Aquatic Environments of the Mississippi River Basin. Quarterly progress report, January 1, 1995--March 31, 1995

    International Nuclear Information System (INIS)

    This progress report covers activities for the period January 1 - March 31, 1995 on project concerning 'Hazardous Materials in Aquatic Environments of the Mississippi River Basin.' The following activities are each summarized by bullets denoting significant experiments/findings: biotic and abiotic studies on the biological fate, transport and ecotoxicity of toxic and hazardous waste in the Mississippi River Basin; assessment of mechanisms of metal-induced reproductive toxicity in quatic species as a biomarker of exposure; hazardous wastes in aquatic environments: biological uptake and metabolism studies; ecological sentinels of aquatic contamination in the lower Mississippi River system; bioremediation of selected contaminants in aquatic environments of the Mississippi River Basin; a sensitive rapid on-sit immunoassay for heavy metal contamination; pore-level flow, transport, agglomeration and reaction kinetics of microorganism; biomarkers of exposure and ecotoxicity in the Mississippi River Basin; natural and active chemical remediation of toxic metals, organics and radionuclides in the aquatic environment; expert geographical information systems for assessing hazardous wastes in aquatic environments; enhancement of environmental education; and a number of just initiated projects including fate and transport of contaminants in aquatic environments; photocatalytic remediation; radionuclide fate and modeling from Chernobyl

  9. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development program. Progress report, October 1, 1981-December 31, 1981. [Alloy-MA-956; alloy-MA-754

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, O.F.

    1982-06-15

    Work covered in this report includes the activities associated with the status of the simulated reactor helium supply systems and testing equipment. The progress in the screening test program is descibed; this includes: screening creep results and metallographic analysis for materials thermally exposed or tested at 750/sup 0/, 850/sup 0/, 950/sup 0/ and 1050/sup 0/C (1382/sup 0/, 1562/sup 0/, 1742/sup 0/, and 1922/sup 0/F) in controlled-purity helium. The status of creep-rupture in controlled-purity helium and air and fatigue testing in the controlled-purity helium in the intensive screening test program is discussed. The results of metallographic studies of screening alloys exposed in controlled-purity helium for 3000 hours at 750/sup 0/C and 5500 hours at 950/sup 0/C, 3000 hours at 1050/sup 0/C and 6000 hours at 1050/sup 0/C and for weldments exposed in controlled-purity helium for 6000 hours at 750/sup 0/C and 6000 hours at 1050/sup 0/C are presented and discussed.

  10. Development of small-bore, high-current-density railgun as testbed for study of plasma-materials interaction. Progress report for October 16,2000 - May 13, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyekyoon [Kevin

    2003-05-14

    The present document is a final technical report summarizing the progress made during 10/16/2000 - 05/13/2003 toward the development of a small-bore railgun with transaugmentation as a testbed for investigating plasma-materials interaction.

  11. Progress report on nuclear science and technology in China (Vol.2). Proceedings of academic annual meeting of China Nuclear Society in 2011, No.4--nuclear material sub-volume

    International Nuclear Information System (INIS)

    Progress report on nuclear science and technology in China (Vol. 2) includes 698 articles which are communicated on the second national academic annual meeting of China Nuclear Society. There are 10 books totally. This is the fourth one, the content is about nuclear material.

  12. Iliotibial band friction syndrome.

    Science.gov (United States)

    Lavine, Ronald

    2010-07-20

    Published articles on iliotibial band friction syndrome have been reviewed. These articles cover the epidemiology, etiology, anatomy, pathology, prevention, and treatment of the condition. This article describes (1) the various etiological models that have been proposed to explain iliotibial band friction syndrome; (2) some of the imaging methods, research studies, and clinical experiences that support or call into question these various models; (3) commonly proposed treatment methods for iliotibial band friction syndrome; and (4) the rationale behind these methods and the clinical outcome studies that support their efficacy.

  13. Laparoscopic gastric banding

    Science.gov (United States)

    ... make the band tighter or looser any time after you have this surgery. It may be tightened or ... Having problems eating Not losing enough weight Vomiting after you eat Outlook (Prognosis) The final weight loss with ...

  14. CSF oligoclonal banding - slideshow

    Science.gov (United States)

    ... presentations/100145.htm CSF oligoclonal banding - series—Normal anatomy ... Overview The cerebrospinal fluid (CSF) serves to supply nutrients to the central nervous system (CNS) and collect waste products, as well as ...

  15. The Band Pass Filter

    OpenAIRE

    Christiano, Lawrence J.; Terry J. Fitzgerald

    1999-01-01

    The `ideal' band pass filter can be used to isolate the component of a time series that lies within a particular band of frequencies. However, applying this filter requires a dataset of infinite length. In practice, some sort of approximation is needed. Using projections, we derive approximations that are optimal when the time series representations underlying the raw data have a unit root, or are stationary about a trend. We identify one approximation which, though it is only optimal for one...

  16. Iliotibial band friction syndrome

    OpenAIRE

    Lavine, Ronald

    2010-01-01

    Published articles on iliotibial band friction syndrome have been reviewed. These articles cover the epidemiology, etiology, anatomy, pathology, prevention, and treatment of the condition. This article describes (1) the various etiological models that have been proposed to explain iliotibial band friction syndrome; (2) some of the imaging methods, research studies, and clinical experiences that support or call into question these various models; (3) commonly proposed treatment methods for ili...

  17. 半纤维素功能材料——水凝胶%Progress in Functional Materials-Hydrogel Based on Hemicellulose

    Institute of Scientific and Technical Information of China (English)

    任俊莉; 彭新文; 孙润仓; 伍红

    2011-01-01

    Recently the preparation of functional biomaterials-hydrogel based on hemicelluloses biomass has obtained a special attention, and the product has exhibited important market prospects and application potential. Compared with synthetic polymer hydrogel, hemicellulo-ses-based hydrogel shows significant advantages, such as environmentally friendly property, bio-compatibility, non-toxicity and biodegrad-ability and so on, which is expected to be used in drug delivery, biosensors, and tissue engineering and other areas. According to the cross-linked type, the methods to prepare hydrogel are divided into physical crosslinking and chemical crosslinking. This paper summarized the research progress of hemicelluloses-based hydrogel materials and the commercial application potential, and pointed out the problems existed and the future development direction in the research of hemicelluloses-based hydrogel.%与各种高分子合成的水凝胶相比,半纤维素基水凝胶具有难以比拟的优势,如环境友好性、生物兼容性、无毒及可降解性等.文中从制备方法角度归纳和总结了木质纤维半纤维素基水凝胶材料近年来的研究进展以及潜在的商业应用前景,并指出了半纤维素基水凝胶在研究中存在的问题及发展方向.

  18. 窄带成像技术对早期食管癌诊断的研究进展%Research progress of narrow band imaging in the diagnosis of early esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    宋来; 彭小东; 杨小红; 付茂勇

    2015-01-01

    早期食管癌的诊断对提高食管癌治疗效果和改善患者预后至关重要.窄带成像技术(NBI)作为一种新的食管癌早期诊断技术,使术者能够清晰观察早期食管癌的黏膜及黏膜下血管的改变,已初步显示出了在食管癌早期诊断中良好的应用价值,相比目前常用的普通白光内镜有明显优势.临床上若与Lugol碘染色内镜、放大内镜等诊断方式联合使用,对食管癌的早期诊断价值更大.%Early diagnosis of esophageal cancer is essential for improving both the effectiveness of esophageal cancer treatment and the prognosis of patients.As a new technology for esophageal cancer early diagnosis,narrow-band imaging (NBI) enables surgeon to clearly observe the mucosa and submucosal blood vessels changes in early esophageal cancer.It has initially shown excellent application value in the early diagnosis.In particular it has obvious advantages to the ordinary white light endoscopy which is currently used in esophageal cancer early diagnosis.If combined with Lugol iodine staining,magnifying endoscopy and other diagnostic methods in clinical,NBI will have a better value in early diagnosis of esophageal.

  19. Mechanical contrast in block copolymers manifested as kink band defects

    Science.gov (United States)

    Winey, Karen I.; Polis, Daniel L.

    1998-03-01

    Kink bands are an established defect structure found in materials with a preferential slip plane, such as select crystalline solids and foliated rocks. Kink bands are induced by steady shear in a predominately parallel-oriented, lamellar poly(styrene-b-ethylene propylene) diblock copolymer. Steady shear induces kink bands which have their boundaries oriented at 45^o relative to the shearing direction. The lamellar orientations inside and outside the kink bands are asymmetric with respect to the kink band boundaries. This asymmetry is due to a lamellar dilation inside the kink band relative to lamellae outside the kink band. A comparison of the zero shear viscosities of homopolystyrene and homopoly(ethylene-propylene) suggest that the PS microdomains deform preferentially. The presence of a preferential slip plane is consistent with the formation of kink bands. Furthermore, estimates of the number of entanglements in the interpenetration zone between opposing brushes suggest an even larger disparity between PS and PEP relaxation times.

  20. Review of wide band-gap semiconductors technology

    Directory of Open Access Journals (Sweden)

    Jin Haiwei

    2016-01-01

    Full Text Available Silicon carbide (SiC and gallium nitride (GaN are typical representative of the wide band-gap semiconductor material, which is also known as third-generation semiconductor materials. Compared with the conventional semiconductor silicon (Si or gallium arsenide (GaAs, wide band-gap semiconductor has the wide band gap, high saturated drift velocity, high critical breakdown field and other advantages; it is a highly desirable semiconductor material applied under the case of high-power, high-temperature, high-frequency, anti-radiation environment. These advantages of wide band-gap devices make them a hot spot of semiconductor technology research in various countries. This article describes the research agenda of United States and European in this area, focusing on the recent developments of the wide band-gap technology in the US and Europe, summed up the facing challenge of the wide band-gap technology.

  1. Banded transformer cores

    Science.gov (United States)

    Mclyman, C. W. T. (Inventor)

    1974-01-01

    A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.

  2. Ultra wide band antennas

    CERN Document Server

    Begaud, Xavier

    2013-01-01

    Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recog

  3. Annual progress report 1981

    International Nuclear Information System (INIS)

    This annual progress report of the CEA Protection and Nuclear Safety Institut outlines a brief description of the progress made in each section of the Institut. Research activities of the Protection department include, radiation effects on man, radioecology and environment radioprotection techniques. Research activities of the Nuclear Safety department include, reactor safety analysis, fuel cycle facilities safety analysis, safety research programs. The third section deals with nuclear material security including security of facilities, security of nuclear material transport and monitoring of nuclear material management

  4. 1985. Annual progress report

    International Nuclear Information System (INIS)

    This annual progress report of the CEA Protection and Nuclear Safety Institut outlines a description of the progress made in each sections of the Institut Research activities of the different departments include: reactor safety analysis, fuel cycle facilities analysis; and associated safety research programs (criticality, sites, transport ...), radioecology and environmental radioprotection techniques; data acquisition on radioactive waste storage sites; radiation effects on man, studies on radioprotection techniques; nuclear material security including security of facilities, security of nuclear material transport, and monitoring of nuclear material management; nuclear facility decommissioning; and finally the public information

  5. Enhancing Solar Cell Efficiency Using Photon Upconversion Materials

    Directory of Open Access Journals (Sweden)

    Yunfei Shang

    2015-10-01

    Full Text Available Photovoltaic cells are able to convert sunlight into electricity, providing enough of the most abundant and cleanest energy to cover our energy needs. However, the efficiency of current photovoltaics is significantly impeded by the transmission loss of sub-band-gap photons. Photon upconversion is a promising route to circumvent this problem by converting these transmitted sub-band-gap photons into above-band-gap light, where solar cells typically have high quantum efficiency. Here, we summarize recent progress on varying types of efficient upconversion materials as well as their outstanding uses in a series of solar cells, including silicon solar cells (crystalline and amorphous, gallium arsenide (GaAs solar cells, dye-sensitized solar cells, and other types of solar cells. The challenge and prospect of upconversion materials for photovoltaic applications are also discussed

  6. New Monolayered Materials Exhibiting Unusual Electronic Properties

    Science.gov (United States)

    Lopez-Bezanilla, Alejandro; Martin, Ivar; Littlewood, Peter B.

    Computationally based approaches are allowing to progress in the discovery and design of nano-scaled materials. Here we propose a series of new mono-layered compounds with exotic properties. By means of density functional theory calculations we demonstrate that the pentagonal arrangement of SiC2 yields an inverted distribution of the p-bands which leads to an unusual electronic behaviour of the material under strain [J. Phys. Chem. C, 2015, 119 (33), pp 19469]. A different pentagonal arrangement of C atoms enables the formation of Dirac cones which, unlike graphene, exhibit a strain-mediated tunable band gap. This work is supported by DOE-BES under Contract No. DE-AC02-06CH11357.

  7. 锂离子电池用石墨烯基负极材料的研究进展%Research progress in graphene-based anode material for Li-ion battery

    Institute of Scientific and Technical Information of China (English)

    高云雷; 赵东林; 白利忠; 景磊

    2012-01-01

    综述了石墨烯和石墨烯基复合材料作为锂离子电池负极材料的研究进展,重点论述了金属氧化物/石墨烯复合材料,对石墨烯基复合材料的发展趋势进行了展望.%Research progress in Li-ion battery anode material ineluding graphene and graphene-based composite was reviewed. Metal oxide/graphene composite was mainly discussed,the development trend of graphene-based anode material was prospected.

  8. 锂离子电池纳米锂锰氧化物正极材料的研究进展%Research Progress in Nano-scale Lithium Manganese Oxide as Cathode Material for Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    曾丽珍

    2012-01-01

    综述了近年来锂离子电池正极材料锂锰氧化物的研究现状,重点对锂锰氧化物的结构和性能的关系,尖晶石锂锰氧化物的制备以及其改性研究进行了阐述。%New progress of nanotechnology applied in lithium ion battery of lithium manganese oxide as cathode material was summarized during recent years,focusing on the relationship between structure and properties of lithium manganese oxide,the preparation methods of nanometer lithium manganese oxide materials cathode material and modification of spinel lithium manganese oxide materials were described.

  9. DUAL BAND MONOPOLE ANTENNA DESIGN

    Directory of Open Access Journals (Sweden)

    P. Jithu

    2013-06-01

    Full Text Available The WLAN and Bluetooth applications become popular in mobile devices, integrating GSM and ISM bands operation in one compact antenna, can reduce the size of mobile devices. Recently, lot many investigations are carried out in designing a dual band antennas with operating frequencies in GSM band and in ISM band for mobile devices. Printed monopoles are under this investigation. In this paper, dual-band printed monopoles are presented to operate at GSM band i.e. 900 MHz and ISM band i.e. 2.4 GHz. We intend to observe the antenna characteristics on the network analyzer and verify the theoretical results with the practical ones.

  10. Flat Chern band in a two-dimensional organometallic framework.

    Science.gov (United States)

    Liu, Zheng; Wang, Zheng-Fei; Mei, Jia-Wei; Wu, Yong-Shi; Liu, Feng

    2013-03-01

    By combining exotic band dispersion with nontrivial band topology, an interesting type of band structure, namely, the flat Chern band, has recently been proposed to spawn high-temperature fractional quantum Hall states. Despite the proposal of several theoretical lattice models, however, it remains doubtful whether such a "romance of flatland" could exist in a real material. Here, we present a first-principles design of a two-dimensional indium-phenylene organometallic framework that realizes a nearly flat Chern band right around the Fermi level by combining lattice geometry, spin-orbit coupling, and ferromagnetism. An effective four-band model is constructed to reproduce the first-principles results. Our design, in addition, provides a general strategy to synthesize topologically nontrivial materials by virtue of organic chemistry and nanotechnology.

  11. University of Illinois at Urbana-Champaign, Materials Research Laboratory progress report for FY 1993 and research proposal for FY 1994

    Energy Technology Data Exchange (ETDEWEB)

    Birnbaum, H.K.

    1993-03-01

    The materials research laboratory program is about 30% of total Materials Science and Engineering effort on the Univ. of Illinois campus. Coordinated efforts are being carried out in areas of structural ceramics, grain boundaries, field responsive polymeric and organic materials, molecular structure of solid-liquid interfaces and its relation to corrosion, and x-ray scattering science.

  12. Formation of Degenerate Band Gaps in Layered Systems

    Directory of Open Access Journals (Sweden)

    Alexey P. Vinogradov

    2012-06-01

    Full Text Available In the review, peculiarities of spectra of one-dimensional photonic crystals made of anisotropic and/or magnetooptic materials are considered. The attention is focused on band gaps of a special type—the so called degenerate band gaps which are degenerate with respect to polarization. Mechanisms of formation and properties of these band gaps are analyzed. Peculiarities of spectra of photonic crystals that arise due to the linkage between band gaps are discussed. Particularly, it is shown that formation of a frozen mode is caused by linkage between Brillouin and degenerate band gaps. Also, existence of the optical Borrmann effect at the boundaries of degenerate band gaps and optical Tamm states at the frequencies of degenerate band gaps are analyzed.

  13. A colored leg banding technique for Amazona parrots

    Science.gov (United States)

    Meyers, J.M.

    1995-01-01

    A technique for individual identification of Amazona was developed using plastic leg bands. Bands were made from 5- and 7-mm-wide strips of laminated PVC coiled 2.5 times with an inside diameter 4-5 mm gt the maximum diameter of the parrot's leg. Seventeen parrots were captured in Puerto Rico, marked with individual plastic leg bands, and observed for 204-658 d with only one lost or damaged plastic band. Plastic leg bands did not cause injury to or calluses on parrots' legs. The plastic material used for making leg bands was available in 18 colors in 1994, which would allow unique marking of 306 individuals using one plastic leg band on each leg.

  14. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    XIANG FuYuan; LIANG ShunLin; LI AiGen

    2009-01-01

    The diffuse interstellar bands (DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s, the exact nature of DIBs still remains unclear. This article reviews the history of the detec-tions of DIBs in the Milky Way and external galaxies, the major observational characteristics of DIBs, the correlations or anti-correlations among DIBs or between DIBs and other interstellar features (e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise), and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  15. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The diffuse interstellar bands(DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s,the exact nature of DIBs still remains unclear. This article reviews the history of the detections of DIBs in the Milky Way and external galaxies,the major observational characteristics of DIBs,the correlations or anti-correlations among DIBs or between DIBs and other interstellar features(e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise),and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  16. Variants of lumbosacral elastic band.

    Directory of Open Access Journals (Sweden)

    Carlos Cesar Santín Alfaro

    2011-06-01

    Full Text Available It is made an intervention research, qualitative and quantitative of two variants of lumbosacral elastic bands used in Provincial Laboratory of Technical Orthopedics in Sancti Spiritus Province, taking into account the high demand for this device and that the laboratory do not often count with the raw material needed for the original lumbosacral belt made by denim cloth which is the conventional belt. The main goal of this research is to explain the technological process and to compare the cost of production of both elastic variants with lumbosacral belt made by cloth which are offer to patients who look for this service , giving them a rapid solution so that they can feel comfortable.

  17. Maximizing band gaps in plate structures

    DEFF Research Database (Denmark)

    Halkjær, Søren; Sigmund, Ole; Jensen, Jakob Søndergaard

    2006-01-01

    Band gaps, i.e., frequency ranges in which waves cannot propagate, can be found in elastic structures for which there is a certain periodic modulation of the material properties or structure. In this paper, we maximize the band gap size for bending waves in a Mindlin plate. We analyze an infinite...... periodic plate using Bloch theory, which conveniently reduces the maximization problem to that of a single base cell. Secondly, we construct a finite periodic plate using a number of the optimized base cells in a postprocessed version. The dynamic properties of the finite plate are investigated...

  18. 稀土锆酸盐热障涂层材料研究进展%Research Progresses of Rare-Earth Zirconate Ceramic Materials for Thermal Barrier Coatings

    Institute of Scientific and Technical Information of China (English)

    项建英; 陈树海; 黄继华; 周国栋; 梁文建; 汪瑞军; 何箐

    2012-01-01

    稀土锆酸盐是最有希望应用于未来高性能航空发动机的热障涂层材料之一.归纳了国内外研究者在稀土锆酸盐类陶瓷材料上取得的结果,系统分析了不同位置全取代或部分取代得到的掺杂陶瓷材料的热物理性能和力学性能,并讨论了热障涂层材料研究的发展趋势,最后指出了稀土高酸盐热障涂层材料需要进一步研究的关键问题.%Rare-earth zirconates is one of the prospective thermal barrier coatings (TBCs) materials for use in high performance turbine engine in the future. The research progress of home and abroad is summarized, and the ther-mo-physical and mechanical properties of ceramic materials which substituted by completely or partly at different elements were analyzed systematically. The research progress and development tendency of ceramic materials for TBCs are analyzed and investigated, and then some key problems of rare-earth zirconates as TBCs materials in further reac-her are reviewed in the end.

  19. Micromechanics of shear banding

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, J.J.

    1992-08-01

    Shear-banding is one of many instabilities observed during the plastic flow of solids. It is a consequence of the dislocation mechanism which makes plastic flow fundamentally inhomogeneous, and is exacerbated by local adiabatic heating. Dislocation lines tend to be clustered on sets of neighboring glide planes because they are heterogeneously generated; especially through the Koehler multiple-cross-glide mechanism. Factors that influence their mobilities also play a role. Strain-hardening decreases the mobilities within shear bands thereby tending to spread (delocalize) them. Strain-softening has the inverse effect. This paper reviews the micro-mechanisms of these phenomena. It will be shown that heat production is also a consequence of the heterogeneous nature of the microscopic flow, and that dislocation dipoles play an important role. They are often not directly observable, but their presence may be inferred from changes in thermal conductivity. It is argued that after deformation at low temperatures dipoles are distributed a la Pareto so there are many more small than large ones. Instability at upper yield point, the shapes of shear-band fronts, and mechanism of heat generation are also considered. It is shown that strain-rate acceleration plays a more important role than strain-rate itself in adiabatic instability.

  20. S-Band Loads for SLAC Linac

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, A.; Decker, F.-J.; /SLAC; LeClair, R.; /INTA Technologies, Santa Clara

    2012-08-28

    The S-Band loads on the current SLAC linac RF system were designed, in some cases, 40+ years ago to terminate 2-3 MW peak power into a thin layer of coated Kanthal material as the high power absorber [1]. The technology of the load design was based on a flame-sprayed Kanthal wire method onto a base material. During SLAC linac upgrades, the 24 MW peak klystrons were replaced by 5045 klystrons with 65+ MW peak output power. Additionally, SLED cavities were introduced and as a result, the peak power in the current RF setup has increased up to 240 MW peak. The problem of reliable RF peak power termination and RF load lifetime required a careful study and adequate solution. Results of our studies and three designs of S-Band RF load for the present SLAC RF linac system is discussed. These designs are based on the use of low conductivity materials.

  1. Progress of Terahertz Devices Based on Graphene

    Institute of Scientific and Technical Information of China (English)

    Mai-Xia Fu; Yan Zhang

    2013-01-01

    Graphene is a one-atom-thick planar sheet of sp2-hybridized orbital bonded honeycomb carbon crystal. Its gapless and linear energy spectra of electrons and holes lead to the unique carrier transport and optical properties, such as giant carrier mobility and broadband flat optical response. As a novel material, graphene has been regarded to be extremely suitable and competent for the development of terahertz (THz) optical devices. In this paper, the fundamental electronic and optic properties of graphene are described. Based on the energy band structure and light transmittance properties of graphene, many novel graphene based THz devices have been proposed, including modulator, generator, detector, and imaging device. This progress has been reviewed. Future research directions of the graphene devices for THz applications are also proposed.

  2. Fossil Energy Advanced Research and Technology Development (AR&TD) Materials Program semiannual progress report for the period ending September 30, 1991. Fossil Energy Program

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, R.R.; Cole, N.C. [comps.

    1992-04-01

    The objective of the Fossil Energy Advanced Research and Technology Development Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The Program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Research is outlined in four areas: Ceramics, New Alloys, Corrosion and Erosion Research, and Technology Development and Transfer. (VC)

  3. Fossil Energy Advanced Research and Technology Development (AR TD) Materials Program semiannual progress report for the period ending September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, R.R.; Cole, N.C. (comps.)

    1992-04-01

    The objective of the Fossil Energy Advanced Research and Technology Development Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The Program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Research is outlined in four areas: Ceramics, New Alloys, Corrosion and Erosion Research, and Technology Development and Transfer. (VC)

  4. Chemistry and Materials Science Weapons-Supporting Research and Laboratory-Directed Research and Development. Second half progress report, FY 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    Thrust areas of the weapons-supporting research are surface research, uranium research, physics and processing of metals, energetic materials. Group study areas included strength of Al and Al-Mg/alumina bonds, advanced synchrotron radiation study of materials, and theory, modeling, and computation. Individual projects were life prediction for composites and thermoelectric materials with exceptional figures of merit. The laboratory-directed R and D include director`s initiatives (aerogel-based electronic devices, molecular levels of energetic materials), individual projects, and transactinium institute studies. An author index is provided.

  5. Progress of Research on the Application of Nano-TiO2 Packaging Materials in Fresh-keeping%纳米TiO2保鲜包装材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    黄瑜

    2012-01-01

    综述了纳米TiO2包装材料的抗茵机理、在保鲜包装上的研究应用现状,并就纳米包装材料的安全性进行了概述,同时对纳米TiO2包装材料的研究和应用前景进行了展望.%The paper summarized the research progress of the nano-TiO2 fresh-keeping materials. The fresh-keeping mechanism and application of nano-TiO2 were discussed in detail,respectively. The safety of nanometer packaging materials was outlined and the prospect of the nano-TiO2 packaging materials was outlooked.

  6. Design and Simulation of Edge-Coupled Stripline Band Pass Filter for U band

    Directory of Open Access Journals (Sweden)

    Pawan Shakdwipee

    2013-08-01

    Full Text Available In this paper, a band pass filter structure using Ansoft designer software and Matlab software simulation tool are presented. The filter is operated at U Band range in higher order 50 GHz edge-coupled Stripline band pass filter for different microwave application. For the proposed work we consider simulation using Roger R03203 substrate with dielectric constant of 3.02, Conductor Thickness 0.035 mm and Substrate Height 0.787 mm. This filter is design at a center frequency of 50 GHz with 8 GHz bandwidth. Simulation results show that the filter operation is optimum and best in this range and results show good performance and agree well with the high frequency EM full wave simulation. In this paper, band pass filter development with the assistance of the Richards-Kuroda Transformation method, is used. Moreover, measured S parameters denote the center frequency is also strongly influenced by the variation of Roger's material's dielectric constants. By analyzing the characteristics at center frequency of the filter, both theoretical and simulated data are accumulated for broadening application filed. The band pass filter exhibits advantages of small size and high reliability compared to conventional planar filter structure, which makes the band pass filter suitable for U Band communicational application. This filter shows attractive characteristics for BPF applications.

  7. Multi-band Image Registration Method Based on Fourier Transform

    Institute of Scientific and Technical Information of China (English)

    庹红娅; 刘允才

    2004-01-01

    This paper presented a registration method based on Fourier transform for multi-band images which is involved in translation and small rotation. Although different band images differ a lot in the intensity and features,they contain certain common information which we can exploit. A model was given that the multi-band images have linear correlations under the least-square sense. It is proved that the coefficients have no effect on the registration progress if two images have linear correlations. Finally, the steps of the registration method were proposed. The experiments show that the model is reasonable and the results are satisfying.

  8. Dendrometer bands made easy: Using modified cable ties to measure incremental growth of trees 1

    OpenAIRE

    Anemaet, Evelyn R.; Beth A. Middleton

    2013-01-01

    • Premise of the study: Dendrometer bands are a useful way to make sequential repeated measurements of tree growth, but traditional dendrometer bands can be expensive, time consuming, and difficult to construct in the field. An alternative to the traditional method of band construction is to adapt commercially available materials. This paper describes how to construct and install dendrometer bands using smooth-edged, stainless steel, cable tie banding and attachable rollerball heads. • Method...

  9. Band structure engineering in organic semiconductors

    Science.gov (United States)

    Schwarze, Martin; Tress, Wolfgang; Beyer, Beatrice; Gao, Feng; Scholz, Reinhard; Poelking, Carl; Ortstein, Katrin; Günther, Alrun A.; Kasemann, Daniel; Andrienko, Denis; Leo, Karl

    2016-06-01

    A key breakthrough in modern electronics was the introduction of band structure engineering, the design of almost arbitrary electronic potential structures by alloying different semiconductors to continuously tune the band gap and band-edge energies. Implementation of this approach in organic semiconductors has been hindered by strong localization of the electronic states in these materials. We show that the influence of so far largely ignored long-range Coulomb interactions provides a workaround. Photoelectron spectroscopy confirms that the ionization energies of crystalline organic semiconductors can be continuously tuned over a wide range by blending them with their halogenated derivatives. Correspondingly, the photovoltaic gap and open-circuit voltage of organic solar cells can be continuously tuned by the blending ratio of these donors.

  10. Band structure engineering in organic semiconductors.

    Science.gov (United States)

    Schwarze, Martin; Tress, Wolfgang; Beyer, Beatrice; Gao, Feng; Scholz, Reinhard; Poelking, Carl; Ortstein, Katrin; Günther, Alrun A; Kasemann, Daniel; Andrienko, Denis; Leo, Karl

    2016-06-17

    A key breakthrough in modern electronics was the introduction of band structure engineering, the design of almost arbitrary electronic potential structures by alloying different semiconductors to continuously tune the band gap and band-edge energies. Implementation of this approach in organic semiconductors has been hindered by strong localization of the electronic states in these materials. We show that the influence of so far largely ignored long-range Coulomb interactions provides a workaround. Photoelectron spectroscopy confirms that the ionization energies of crystalline organic semiconductors can be continuously tuned over a wide range by blending them with their halogenated derivatives. Correspondingly, the photovoltaic gap and open-circuit voltage of organic solar cells can be continuously tuned by the blending ratio of these donors. PMID:27313043

  11. Development of New Low-Cost, High-Performance, PV Module Encapsulant/Packaging Materials: Final Technical Progress Report, 22 October 2002 - 15 November 2007

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, R.

    2008-04-01

    Report on objectives to work with U.S.-based PV module manufacturers (c-Si, a-Si, CIS, other thin films) to develop/qualify new low-cost, high-performance PV module encapsulant/packaging materials, and processes using the packaging materials.

  12. Electronic pairing mechanism due to band modification in a two-band model: Tc evaluation

    International Nuclear Information System (INIS)

    Following the electronic model developed by us previously (Mizia and Romanowski, Mizia) we estimate the superconducting transition temperature in a simple electronic two-band model for materials characterized by a broad superconducting band and a narrow level within the same energy range. A large electron deformation coupling constant and large electron correlation effects are assumed. It is shown that high-temperature superconductivity is entirely possible within a range of reasonable electronic parameters. This model does not assume any artificial interactions to obtain a negative pairing potential. Instead, the negative part of the electronic interaction potential comes from the modification of the electron dispersion relation with growing number of superconducting pairs. Such a modification is possible in soft electronic systems, i.e. in systems partial to band modification due to large internal stresses, strong electronic correlation effects and broad band narrow level charge transfer during the superconducting transition. (orig.)

  13. Research Progress and Thermal Properties of Wax Composite Phase Change Materials%石蜡复合相变材料的研究进展及其热学性质

    Institute of Scientific and Technical Information of China (English)

    王诗语; 凌凤香; 孙剑锋; 严益民; 李龙

    2015-01-01

    Paraffin wax as a kind of phase transition energy storage material has the characteristics of no-supercooling, no-separate-out, stable, non-toxic, non-corrosive and low price etc. Paraffin wax composite phase transition energy storage materials can not only avoid the disadvantages of single organic or inorganic phase transition energy storage materials, but also improve the performance of the phase transition energy storage materials and widen the application range of the phase transition energy storage materials. In this thesis, research progress and thermal properties of wax composite phase change materials were introduced.%石蜡作为相变储能材料具有不存在过冷及析出现象,性能稳定,无毒,无腐蚀,价格便宜等优点。石蜡复合相变储能材料弥补了石蜡作为相变储能材料的缺点,改进了在实际应用中相变材料的效果,并且扩大了石蜡相变储能材料应用的领域。主要介绍了国内外对石蜡复合相变储能材料的研讨及相关热学性质。

  14. Band-Notched Ultrawide Band Planar Inverted-F Antenna

    Directory of Open Access Journals (Sweden)

    H. T. Chattha

    2012-01-01

    Full Text Available A novel ultrawide band planar inverted-F antenna with band-notched characteristics is presented in this paper. The planar inverted-F antenna uses two parasitic elements to enhance the bandwidth to cover the ultrawide band. The band-notched feature is added by inserting a W-shaped slot on the top radiating element of the antenna with a band rejection from 5.08 to 6 GHz (measured. Both the measured and simulated results are obtained to draw the conclusions.

  15. Investigation of test methods, material properties, and processes for solar cell encapsulants. Seventh quarterly progress report, November 12, 1977--February 12, 1978

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-02-01

    The goal of this program is to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. Flat-plate solar collector systems have been considered and six basic construction elements identified. Materials surveys were continued. Silicones, fluorocarbons, glass, and acrylic polymers have the highest inherent weatherability of materials studied to date. A survey of transparent acrylic molding resins demonstrates that unfortunately acrylic sheets are too expensive to satisfy superstrate or substrate functions. Soda-lime glass still appears to be the most cost-effective superstrate material. As protective covers (i.e., outer coatings and under coatings), the acrylics are excellent candidates. No pourable or processable acrylic elastomers that could be used as pottants have yet been found. A first-cut material cost allocation based on $0.25 per square foot was developed for the six construction elements, and substrates were subsequently assessed to be 40 to 60 percent of the encapsulation expense. A survey of various candidate substrate materials singularly identifies wood composites as the lowest costing material for this application. Other composites demonstrating high strength-to-weight ratios are also being explored.

  16. Research Progress of High Capacity Si Based Anode Material for Li-Ion Battery%锂离子电池用高容量合金类硅基负极材料研究进展

    Institute of Scientific and Technical Information of China (English)

    沈龙; 董爱想; 乔永民; 吴敏昌

    2012-01-01

      锡、硅负极材料由于具有高的比容量等优点,成为提高锂离子电池能量密度的首选负极材料。首先介绍了目前产业界开发锡、硅负极材料的进展,并从商业化的角度比较了这两类材料在开发工艺及实际使用电性能方面的区别。进一步从基础研发角度重点阐述了不同结构的硅基材料(单质硅、硅氧化物、硅碳复合物及硅合金)的电性能改性研究进展,指出了具有工业化前景的工艺方法。%  Tin and Silicon-based compounds are the research focuses of high capacity anode material for lithium ion batteries. The research progress of Si&Sn materials is introduced, and their process development from commercial perspective is also compared. The electrochemical behaviors modification progresses of Si materials, which are crystal silicon、silicon oxygen compound, Si/C composite and silicon alloy, have been reported. The process route which is fit for industrialization has been provided.

  17. Progress in Lithium Ion Battery Energy Materials%锂离子电池能源材料研究进展

    Institute of Scientific and Technical Information of China (English)

    苏航; 陶城; 缪文泉; 程伶俐; 王勇; 焦正

    2011-01-01

    Energy materials are the materials used in development, transportation, storage and utilization of energy. Rechargeable lithium ion batteries materials are the best developed and applied energy materials. The performance of a battery greatly depends on the choice and optimization of electrode materials. This article reviews the research advances in new electrode materials for lithium ion batteries at the School of Environmental and Chemical Engineering, Shanghai University. These include tin oxides nano-particles, tin oxides/carbon nanocomposites, nano carbon materials, carbon coated LiFePO4 cathode materials, CoO/carbon nanocomposites, and NiO/graphene nanocomposites. The development trend of these materials is summarized.%能源材料是指能源的开发、运输、转换、储存和利用过程中的材料,其中锂离子电池材料是应用和开发前景最好的一种能源材料.改善和提高锂离子电池电化学性能的关键是选取充放电性能良好的电极材料.总结上海大学环境与化学工程学院在新型电极材料领域的研究进展,其中包括锡基纳米粒子、锡基/碳复合纳米材料、碳纳米材料、碳包裹磷酸铁锂复合纳米材料、氧化钴/碳复合纳米材料、氧化镍/石墨烯复合纳米材料,并对该类材料的发展趋势进行展望.

  18. 纳米材料在食品包装中的应用研究进展%Progress on Application Research of Nanometer Material for Food Packaging

    Institute of Scientific and Technical Information of China (English)

    徐绍虎

    2011-01-01

    介绍了纳米材料在食品包装中的应用,指出了与传统的食品包装材料相比,纳米材料在保鲜效果、抗菌能力以及阻隔性能方面更加优越,应用前景广阔。%The applications of nanometer material in food packaging were summarized.Compared with conventional food packaging material,nanometer packaging material is much better in fresh-keeping effect,resistance to microbes and barrier properties.Nanometer packagi

  19. The Oxygen a Band

    Science.gov (United States)

    Benner, D. Chris; Devi, V. Malathy; Hoo, Jiajun; Hodges, Joseph; Long, David A.; Sung, Keeyoon; Drouin, Brian; Okumura, Mitchio; Bui, Thinh Quoc; Rupasinghe, Priyanka

    2014-06-01

    The oxygen A band is used for numerous atmospheric experiments, but spectral line parameters that sufficiently describe the spectrum to the level required by OCO2 and other high precision/accuracy experiments are lacking. Fourier transform spectra from the Jet Propulsion Laboratory and cavity ring down spectra from the National Institute of Standards and Technology were fitted simultaneously using the William and Mary multispectrum nonlinear least squares fitting technique into a single solution including the entire band. In addition, photoacoustic spectra already available from the California Institute of Technology will be added to the solution. The three types of spectrometers are complementary allowing the strengths of each to fill in the weaknesses of the others. With this technique line positions, intensities, widths, shifts, line mixing, Dicke narrowing, temperature dependences and collision induced absorption have been obtained in a single physically consistent fit. D. Chris Benner, C. P. Rinsland, V. M. Devi, M. A. H. Smith, and D. Atkins, JQSRT 1995;53:705-21. Part of the research described in this paper was performed at The College of William and Mary, the, Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration and the Jet Propulsion Laboratory. Support for the National Institute of Standards and Technology was provided by the NIST Greenhouse Gas Measurements and Climate Research Program and a NIST Innovations in Measurement Science (IMS) award.

  20. Solid state dielectric screening versus band gap trends and implications

    Science.gov (United States)

    Ravichandran, Ram; Wang, Alan X.; Wager, John F.

    2016-10-01

    High-frequency (optical) and low-frequency (static) dielectric constant versus band gap trends, as well as index of refraction versus band gap trends are plotted for 107 inorganic semiconductors and insulators. These plots are describable via power-law fitting. Dielectric screening trends that emerge from this analysis have important optical and electronic implications. For example, barrier lowering during Schottky emission, phonon-assisted or Fowler-Nordheim tunneling, or Frenkel-Poole emission from a trap is found to be significantly more pronounced with increasing band gap due to a reduction in the optical dielectric constant with increasing band gap. The decrease in the interface state density with increasing band gap is another optical dielectric constant trend. The tendency for a material with a wider band gap to be more difficult to dope is attributed to an increase in the ionization energy of the donor or acceptor dopant, which in turn, depends on the optical dielectric constant and the effective mass. Since the effective mass for holes is almost always larger than that for electrons, p-type doping is more challenging than n-type doping in a wide band gap material. Finally, the polar optical phonon-limited mobility depends critically upon the reciprocal difference of the optical and the static dielectric constant. Consequently, electron and hole mobility tend to decrease with increasing band gap in a polar material.