WorldWideScience

Sample records for band materials progress

  1. Progressive Band Selection

    Science.gov (United States)

    Fisher, Kevin; Chang, Chein-I

    2009-01-01

    Progressive band selection (PBS) reduces spectral redundancy without significant loss of information, thereby reducing hyperspectral image data volume and processing time. Used onboard a spacecraft, it can also reduce image downlink time. PBS prioritizes an image's spectral bands according to priority scores that measure their significance to a specific application. Then it uses one of three methods to select an appropriate number of the most useful bands. Key challenges for PBS include selecting an appropriate criterion to generate band priority scores, and determining how many bands should be retained in the reduced image. The image's Virtual Dimensionality (VD), once computed, is a reasonable estimate of the latter. We describe the major design details of PBS and test PBS in a land classification experiment.

  2. 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.

  3. 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.

  4. Progressive band processing of fast iterative pixel purity index

    Science.gov (United States)

    Li, Yao; Chang, Chein-I.

    2016-05-01

    Fast Iterative Pixel Purity Index (FIPPI) was previously developed to address two major issues arising in PPI which are the use of skewers whose number must be determined by a priori and inconsistent final results which cannot be reproduced. Recently, a new concept has been developed for hyperspectral data communication according to Band SeQuential (BSQ) acquisition format in such a way that bands can be collected band by band. By virtue of BSQ users are able to develop Progressive Band Processing (PBP) for hyperspectral imaging algorithms so that data analysts can observe progressive profiles of inter-band changes among bands. Its advantages have been justified in several applications, anomaly detection, constrained energy minimization, automatic target generation process, orthogonal subspace projection, PPI, etc. This paper further extends PBP to FIPPI. The idea to implement PBP-FIPPI is to use two loops specified by skewers and bands to process FIPPI. Depending upon which one is implemented in the outer loop two different versions of PBP-FIPPI can be designed. When the outer loop is iterated band by band, it is called to be called Progressive Band Processing of FIPPI (PBP-FIPPI). When the outer loop is iterated by growing skewers, it is called Progressive Skewer Processing of FIPPI (PSP-FIPPI). Interestingly, both versions provide different insights into the design of FIPPI but produce close results.

  5. Band description of materials with localizing orbitals

    Energy Technology Data Exchange (ETDEWEB)

    Koelling, D.D.

    1986-03-01

    Density functional theory is a form of many-body theory which maps the problem onto an equivalent single particle-like system by limiting to the ground state (or some limited ensemble). So it should be surprising that this ground state theory could have any relevance whatsoever to the excitation properties of a material - and yet it does when used carefully. However, the most interesting materials involve active orbitals which are at least partially localized in space and this has profound effects both on the ground state and the excitation spectrum. My long term interest is in Ce and actinide compounds such that the popular concerns are mixed valence, heavy fermions, and the various forms of magnetic transitions. Band structure calculations can give a great deal of information concerning the mechanisms and degree of the localization as shown by examples using the Ce and U Ll/sub 2/ structured materials and the Ce cubic Laves phase materials. There are some difficulties due to an incomplete knowledge of the functionals involved which causes an underestimate of the local character. This is illustrated and discussed.

  6. Analysis on Band Gaps of MCM-41 Type of Materials

    Institute of Scientific and Technical Information of China (English)

    HAN Pei-de; LIANG Jian; XU Bing-she; LIU Xu-guang; PENG Lian-mao

    2004-01-01

    The concept and analysis method of photonic crystals and band gaps are introduced into one-dimensional(1D) ordered mesoporous materials. MCM-41 type of materials are treated theoretically as photonic crystals. The formation of band gaps is exhibited and confirmed by a calculation of transfer matrix technique. PBG was found around 9-42 nm in soft X-ray region. The photonic band-gap was predicted to be dependent on incident direction, pore size and lattice constant. The mesoporous materials with different pore sizes and different lattice constants have different band-gap widths.

  7. 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.

  8. 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.

  9. Designer disordered materials with large complete photonic band gaps

    CERN Document Server

    Florescu, Marian; Steinhardt, Paul J; 10.1073/pnas.0907744106

    2010-01-01

    We present designs of 2D isotropic, disordered photonic materials of arbitrary size with complete band gaps blocking all directions and polarizations. The designs with the largest gaps are obtained by a constrained optimization method that starts from a hyperuniform disordered point pattern, an array of points whose number variance within a spherical sampling window grows more slowly than the volume. We argue that hyperuniformity, combined with uniform local topology and short-range geometric order, can explain how complete photonic band gaps are possible without long-range translational order. We note the ramifications for electronic and phononic band gaps in disordered materials.

  10. Recent progress in hybrid materials science.

    Science.gov (United States)

    Sanchez, Clément; Shea, Kenneth J; Kitagawa, Susumu

    2011-02-01

    This themed issue of Chemical Society Reviews reviews recent progress made in hybrid materials science. Guest editors Clément Sanchez, Susumu Kitagawa and Ken Shea introduce the issue and the academic and industrial importance of the field.

  11. 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.

  12. 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

  13. Adiabatic shear bands localization in materials undergoing deformations

    Science.gov (United States)

    Ryabov, P. N.; Kudryashov, N. A.; Muratov, R. V.

    2017-01-01

    We consider the adiabatic shear banding phenomenon in composite materials undergoing the high speed shear deformations. The mathematical model of adiabatic shear banding in thermo-visco-plastic material is given. New two step numerical algorithm which is based on the Courant-Isaacson-Rees scheme that allows one to simulate fully localized plastic flow from initial stage of localization is proposed. To test this numerical algorithm we use three benchmark problems. The testing results show the accuracy and efficiency of proposed algorithm. The features of adiabatic shear bands formation in composites are studied. The existence of characteristic depth of localization in composites is shown. Influence of initial temperature distribution on the processes of adiabatic shear bands formation in composites is considered.

  14. 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...

  15. 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.

  16. Surface Material Characterization from Multi-band Optical Observations

    Science.gov (United States)

    Hall, D.

    2010-09-01

    Ground-based optical and radar sites routinely acquire resolved images of satellites. These resolved images provide the means to construct accurate wire-frame models of the observed body, as well as an understanding of its orientation as a function of time. Unfortunately, because such images are typically acquired in a single spectral band, they provide little information on the types of materials covering the satellite's various surfaces. Detailed surface material characterization generally requires spectrometric and/or multi-band photometric measurements. Fortunately, many instruments provide such multi-band information (e.g., spectrographs and multi-channel photometers). However, these sensors often measure the brightness of the entire satellite, with no spatial resolution at all. Because such whole-body measurements represent a summation of contributions from many reflecting surfaces, an ―un-mixing‖ or inversion process must be employed to determine the materials covering each of the satellite's individual sub-components. The first section of this paper describes the inversion theory required to retrieve satellite surface material properties from temporal sequences of whole-body multi-band brightness measurements. The inversion requires the following as input: 1) a set of multi-band measurements of a satellite's reflected-sunlight brightness, 2) the satellite's wire-frame model, including each major component capable of reflecting sunlight, 3) the satellite's attitude, specifying the body’s orientation at the time of each multi-band measurement, and 4) a database of bi-directional reflection distribution functions for a set of candidate surface materials. As output, the inversion process yields estimates of the fraction of each major satellite component covered by each candidate material. The second section of the paper describes several tests of the method by applying it to simulated multi-band observations of a cubical satellite with different materials

  17. 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.

  18. Application Progress of the Narrow Band-gap Conjugated Polymer Base on Carbazolyl Materials for Solar Cells%咔唑基窄带隙共轭聚合物太阳能电池材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    苏雪花; 夏德强; 王守伟

    2012-01-01

    基于咔唑基窄带隙共轭聚合物的太阳能电池材料的研究取得突破性的进展,成为当前聚合物光伏器件研究的热点课题之一。概述了咔唑基窄带隙共轭聚合物作为电子给体材料的研究进展及存在的问题,提出了光谱响应更宽、光电转换效率更高的咔唑基共轭聚合物研究的发展前景。%The study of the narrow band-gap conjugated polymer base on carbazolyl materials for application in solar cells gained breakthrough progress,and became one of hotspot issue of the polymer photovoltaic device research at present.The research progress and its main existing problems of the narrow band-gap conjugated polymers base on carbazolyl as electron donor materials were summarized,the study development prospects of the conjugated polymers based on carbazole with broader spectral response and higher incident photon-to-current conversion efficiency were proposed.

  19. Adiabatic Shear Bands in Simple and Dipolar Viscoplastic Materials

    Science.gov (United States)

    1991-08-01

    shear banding, especially from a materials point oi *iew Experimental studies dealing with adiabatic .hear Danding mciude those of Zener and Hollomon...and especially in the region surrounding the center of the block, alters. The nonhomogeneity of the deformation near the corners is now evident...describe ehe work-hardening of the material and accounts approxi- mately for the history of ehe deformation. The rate of evolucion of 4> is assumed

  20. Multiple shear band development and related instabilities in granular materials

    Science.gov (United States)

    Gajo, A.; Bigoni, D.; Wood, D. Muir

    2004-12-01

    A new, small-strain constitutive model, incorporating elastoplastic coupling to describe developing elastic anisotropy, and density as a state variable to capture compaction and dilation, is proposed to simulate the behaviour of granular materials, in particular sand. This developing elastic anisotropy is related to grain reorientation and is shown to be crucial to obtain localisation during strain hardening, as experiments exhibit. Post-localisation analysis is also performed under simplificative assumptions, which evinces a number of features, including softening induced by localisation, size effects and snap-back, all phenomena found in qualitative and quantitative agreement with experiments. No prior model of granular material deformation correctly captures all these behaviours. The post-localisation analysis has revealed a new form of material instability in granular materials, consisting of a saturation mechanism, in which shear bands just formed unload, permitting new bands to form. This phenomenon shares similarities with the mechanics of phase transformation in metal strips and results in a stress oscillation during increasing deformation. The investigation of this mechanism of localised deformation reveals that loose and dense sands behave in qualitatively different ways. In particular, saturation is not persistent in dense sand; rather, after several shear bands form and saturate, this process is terminated by the formation of a differently inclined shear band occurring in the material transformed by previous strain localisation. In this case, the resulting 'global' stress-strain curve exhibits a few stress oscillations followed by a strong softening. On the other hand, band saturation is found to be a persistent phenomenon in loose sand, yielding a continuing stress oscillation. This provides a consistent description of specific experimental results.

  1. Unfolding the band structure of non-crystalline photonic band gap materials.

    Science.gov (United States)

    Tsitrin, Samuel; Williamson, Eric Paul; Amoah, Timothy; Nahal, Geev; Chan, Ho Leung; Florescu, Marian; Man, Weining

    2015-08-20

    Non-crystalline photonic band gap (PBG) materials have received increasing attention, and sizeable PBGs have been reported in quasi-crystalline structures and, more recently, in disordered structures. Band structure calculations for periodic structures produce accurate dispersion relations, which determine group velocities, dispersion, density of states and iso-frequency surfaces, and are used to predict a wide-range of optical phenomena including light propagation, excited-state decay rates, temporal broadening or compression of ultrashort pulses and complex refraction phenomena. However, band calculations for non-periodic structures employ large super-cells of hundreds to thousands building blocks, and provide little useful information other than the PBG central frequency and width. Using stereolithography, we construct cm-scale disordered PBG materials and perform microwave transmission measurements, as well as finite-difference time-domain (FDTD) simulations. The photonic dispersion relations are reconstructed from the measured and simulated phase data. Our results demonstrate the existence of sizeable PBGs in these disordered structures and provide detailed information of the effective band diagrams, dispersion relation, iso-frequency contours, and their angular dependence. Slow light phenomena are also observed in these structures near gap frequencies. This study introduces a powerful tool to investigate photonic properties of non-crystalline structures and provides important effective dispersion information, otherwise difficult to obtain.

  2. 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.

  3. 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.

  4. Electronic materials with a wide band gap: recent developments

    Directory of Open Access Journals (Sweden)

    Detlef Klimm

    2014-09-01

    Full Text Available The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap Eg = 0.66 eV after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (Eg = 1.12 eV. This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider Eg were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and β-Ga2O3, offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity.

  5. Final Technical Progress Report NANOSTRUCTURED MAGNETIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Charles M. Falco

    2012-09-13

    This report describes progress made during the final phase of our DOE-funded program on Nanostructured Magnetic Materials. This period was quite productive, resulting in the submission of three papers and presentation of three talks at international conferences and three seminars at research institutions. Our DOE-funded research efforts were directed toward studies of magnetism at surfaces and interfaces in high-quality, well-characterized materials prepared by Molecular Beam Epitaxy (MBE) and sputtering. We have an exceptionally well-equipped laboratory for these studies, with: Thin film preparation equipment; Characterization equipment; Equipment to study magnetic properties of surfaces and ultra-thin magnetic films and interfaces in multi-layers and superlattices.

  6. 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).

  7. Kohn-Sham potential with discontinuity for band gap materials

    Science.gov (United States)

    Kuisma, M.; Ojanen, J.; Enkovaara, J.; Rantala, T. T.

    2010-09-01

    We model a Kohn-Sham potential with the discontinuity at integer particle numbers starting from the approximation by (GLLB) Gritsenko [Phys. Rev. A 51, 1944 (1995)10.1103/PhysRevA.51.1944]. We evaluate the Kohn-Sham gap and the discontinuity to obtain the quasiparticle gap. This allows us to compare the Kohn-Sham gaps to those obtained by accurate many-body perturbation-theory-based optimized potential methods. In addition, the resulting quasiparticle band gap is compared to experimental gaps. In the GLLB model potential, the exchange-correlation hole is modeled using a generalized gradient approximation (GGA) energy density and the response of the hole-to-density variations is evaluated by using the common-denominator approximation and homogeneous electron-gas-based assumptions. In our modification, we have chosen the PBEsol potential as the GGA to model the exchange hole and add a consistent correlation potential. The method is implemented in the GPAW code, which allows efficient parallelization to study large systems. A fair agreement for Kohn-Sham and the quasiparticle band gaps with semiconductors and other band gap materials is obtained with a potential which is as fast as GGA to calculate.

  8. 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

  9. 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.

  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 ...... by material data which are representative for polymer matrix composites for which experimental work exists. (C) 1999 Elsevier Science Ltd. All rights reserved.......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...

  11. Material progress at Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, A.M.

    1978-01-01

    A brief general description is presented about the principal problems observed on the materials used in the Cerro Prieto geothermal project. These include those problems that have been observed in drill pipes, well casing separation equipment and conduction pipes for geothermal water and steam as well as the problems observed in geothermal power plant materials.

  12. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials.

    Science.gov (United States)

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-12-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

  13. Progress in the materials science of silicene.

    Science.gov (United States)

    Yamada-Takamura, Yukiko; Friedlein, Rainer

    2014-12-01

    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.

  14. Recent Progress In Infrared Fiber Material Research

    Science.gov (United States)

    Gannon, John R.; Byron, Kevin C.

    1982-12-01

    This paper reviews some recent developments in the field of infra-red transmitting glasses. A variety of heavy metal fluoride glasses are currently being investigated with a view to fabricating high performance optical fibre systems. In order to assess the bandwidth potential of these fibres, a computer model of fibre dispersion has been developed, in which accurate calculations of the materials, waveguide, profile and total dispersions are made over a broad wavelength range. Predictions are also made of the range of choice in Δn and core diameter available to give zero total dispersion at particular wavelengths in practical fibres made with these materials.

  15. A Bespoke Single-Band Hubbard Model Material

    OpenAIRE

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

    2015-01-01

    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 effects in solids, but beyond one dimension its solution is intractable. Much current research aims, therefore, at finding appropriate approximations to the Hubbard model phase diagram. Here we take the new ap...

  16. Recent Progress in Advanced Materials for Lithium Ion Batteries

    OpenAIRE

    Jiajun Chen

    2013-01-01

    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 ...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 高效窄带隙共轭聚合物太阳能电池材料设计及器件性能研究进展%Recent Progress of Design and Device of High Efficiency Low Band Gap Conjugated Polymer Materials for Application in Solar Cells

    Institute of Scientific and Technical Information of China (English)

    霍延平; 聂晓李; 方小明

    2012-01-01

    窄带隙聚合物材料因能与太阳光谱更好地匹配而备受重视,是聚合物太阳能电池的研究热点.按照窄带隙聚合物给体单元的结构分类,总结了含芴、硅芴、咔唑、环戊二烯并双噻吩、三苯胺和吩噻嗪给体单元的太阳能电池材料的设计以及器件性能,介绍了聚合物的HOMO和LUMO能隙值对其光谱和光电转换效率的影响,并指出了该研究领域目前存在的问题及今后的发展方向.%Low band gap conjugated polymer materials have attracted great interest in the research field of novel solar cells due to their spectrum matching the solar spectrum. Design and device of various types of low band gap polymer materials are summarized briefly, according to different donor units, such as fluorene, silafluorene carbazole, cy-clopenta[2,l-b:3, 4-b']dithiophene(CPDT) , triarylamine and phenothiazine-based polymers. The magnitude of the band gap and the energy positions of the HOMO and LUMO energy levels are the most important characteristics for determining the optical and electrical properties of a given conjugated polymer. These in turn greatly influence the ultimate power conversion efficiency. The existing problems and future prospect of this kind of materials are discussed.

  4. 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

  5. Progress in advanced high temperature turbine materials, coatings, and technology

    Science.gov (United States)

    Freche, J. C.; Ault, G. M.

    1978-01-01

    Advanced materials, coatings, and cooling technology is assessed in terms of improved aircraft turbine engine performance. High cycle operating temperatures, lighter structural components, and adequate resistance to the various environmental factors associated with aircraft gas turbine engines are among the factors considered. Emphasis is placed on progress in development of high temperature materials for coating protection against oxidation, hot corrosion and erosion, and in turbine cooling technology. Specific topics discussed include metal matrix composites, superalloys, directionally solidified eutectics, and ceramics.

  6. Shear Banding of Soft Glassy Materials in Large Amplitude Oscillatory Shear

    Science.gov (United States)

    Radhakrishnan, Rangarajan; Fielding, Suzanne M.

    2016-10-01

    We study shear banding in soft glassy materials subject to a large amplitude oscillatory shear flow (LAOS). By numerical simulations of the widely used soft glassy rheology model, supplemented by more general physical arguments, we demonstrate strong banding over an extensive range of amplitudes and frequencies of the imposed shear rate γ ˙(t )=γ˙0cos (ω t ), even in materials that do not permit banding as their steady state response to a steadily imposed shear flow γ ˙=γ˙0=const. Highly counterintuitively, banding persists in LAOS even in the limit of zero frequency ω →0 , where one might a priori have expected a homogeneous flow response in a material that does not display banding under conditions of steadily imposed shear. We explain this finding in terms of an alternating competition within each cycle between glassy aging and flow rejuvenation. Our predictions have far-reaching implications for the flow behavior of aging yield stress fluids, suggesting a generic expectation of shear banding in flows of even arbitrarily slow time variation.

  7. A wide-band dielectric characterization system for liquid materials of interest in biology

    OpenAIRE

    Bramanti, Mauro

    1995-01-01

    In many fields of applied research the interest exhists for wide-band dielectric ,characterization of liquid materials, for example, aqueous solutions of biological materials. For this purpose a particular procedure is here proposed, based on the use of a Vectorial Network Analyzer and a suitably designed cell which contains the material under test. Fundamental features of this method are: dielectric characterization directly in the frequency domain without the use of a Fourier inverse trasfo...

  8. 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.

  9. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

    OpenAIRE

    2015-01-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase....

  10. Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress

    Directory of Open Access Journals (Sweden)

    Jin Min Wang

    2010-11-01

    Full Text Available The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO3, crystalline WO3 nanoparticles and nanorods, mesoporous WO3 and TiO2, poly(3,4-ethylenedioxythiophene nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed.

  11. 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.

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

    Science.gov (United States)

    Wickramaratne, Darshana; Zahid, Ferdows; Lake, Roger K.

    2015-08-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wickramaratne, Darshana, E-mail: darshanaw@engineering.ucsb.edu, E-mail: rlake@ece.ucr.edu; Lake, Roger K., E-mail: darshanaw@engineering.ucsb.edu, E-mail: rlake@ece.ucr.edu [Laboratory for Terahertz and Terascale Electronics, Department of Electrical and Computer Engineering, University of California, Riverside, California 92521 (United States); Zahid, Ferdows [Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2015-08-21

    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 Bi{sub 2}Se{sub 3}, 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 Bi{sub 2}Se{sub 3} 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.

  14. 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

  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. Spectrophotometric method for optical band gap and electronic transitions determination of semiconductor materials

    Science.gov (United States)

    Sangiorgi, Nicola; Aversa, Lucrezia; Tatti, Roberta; Verucchi, Roberto; Sanson, Alessandra

    2017-02-01

    The optical band gap energy and the electronic processes involved are important parameters of a semiconductor material and it is therefore important to determine their correct values. Among the possible methods, the spectrophotometric is one of the most common. Several methods can be applied to determine the optical band gap energy and still now a defined consensus on the most suitable one has not been established. A highly diffused and accurate optical method is based on Tauc relationship, however to apply this equation is necessary to know the nature of the electronic transitions involved commonly related to the coefficient n. For this purpose, a spectrophotometric technique was used and we developed a graphical method for electronic transitions and band gap energy determination for samples in powder form. In particular, the n coefficient of Tauc equation was determined thorough mathematical elaboration of experimental results on TiO2 (anatase), ZnO, and SnO2. The results were used to calculate the band gap energy values and then compared with the information obtained by Ultraviolet Photoelectron Spectroscopy (UPS). This approach provides a quick and accurate method for band gap determination through n coefficient calculation. Moreover, this simple but reliable method can be used to evaluate the nature of electronic transition that occurs in a semiconductor material in powder form.

  17. Laser-induced optical breakdown spectroscopy of polymer materials based on evaluation of molecular emission bands

    Science.gov (United States)

    Trautner, Stefan; Jasik, Juraj; Parigger, Christian G.; Pedarnig, Johannes D.; Spendelhofer, Wolfgang; Lackner, Johannes; Veis, Pavel; Heitz, Johannes

    2017-03-01

    Laser-induced breakdown spectroscopy (LIBS) for composition analysis of polymer materials results in optical spectra containing atomic and ionic emission lines as well as molecular emission bands. In the present work, the molecular bands are analyzed to obtain spectroscopic information about the plasma state in an effort to quantify the content of different elements in the polymers. Polyethylene (PE) and a rubber material from tire production are investigated employing 157 nm F2 laser and 532 nm Nd:YAG laser ablation in nitrogen and argon gas background or in air. The optical detection reaches from ultraviolet (UV) over the visible (VIS) to the near infrared (NIR) spectral range. In the UV/VIS range, intense molecular emissions, C2 Swan and CN violet bands, are measured with an Echelle spectrometer equipped with an intensified CCD camera. The measured molecular emission spectra can be fitted by vibrational-rotational transitions by open access programs and data sets with good agreement between measured and fitted spectra. The fits allow determining vibrational-rotational temperatures. A comparison to electronic temperatures Te derived earlier from atomic carbon vacuum-UV (VUV) emission lines show differences, which can be related to different locations of the atomic and molecular species in the expanding plasma plume. In the NIR spectral region, we also observe the CN red bands with a conventional CDD Czerny Turner spectrometer. The emission of the three strong atomic sulfur lines between 920 and 925 nm is overlapped by these bands. Fitting of the CN red bands allows a separation of both spectral contributions. This makes a quantitative evaluation of sulfur contents in the start material in the order of 1 wt% feasible.

  18. [Broad excitation band alkaline-earth silicate luminescent materials activated by rare earth and its applications].

    Science.gov (United States)

    Xia, Wei; Lei, Ming-Kai; Luo, Xi-Xian; Xiao, Zhi-Guo

    2008-01-01

    Series of novel broad excitation band phosphors M2 MgSis O7 : Eu, Dy(M = Ca, Sr) were prepared by a high temperature solid-state reaction method. The crystal structure of compound was characterized. And the effects of part substitution of alkaline-earth on crystal structure, photoluminescence spectra and luminescence properties were also investigated. It is found that the excitation band of silicate luminescent materials extend to visible region and they exhibit yellow, green and blue long after-glow luminescence after excited by ultraviolet or visible light. Ca MgSi O7 : Eu, Dy luminescent materials can be excited effectively under the 450-480 nm range and exhibit a strong emission at 536 nm, nicely combining with blue light emitted by InGaN chips to produce white light. This promises the silicate luminescent materials a potential yellow phosphor for white LED.

  19. Cholesteric liquid crystalline materials with a dual circularly polarized light reflection band fixed at room temperature.

    Science.gov (United States)

    Agez, Gonzague; Mitov, Michel

    2011-05-26

    An unpolarized normal-incidence light beam reflected by a cholesteric liquid crystal is left- or right-circularly polarized, in the cholesteric temperature range. In this article, we present a novel approach for fabricating a cholesteric liquid crystalline material that exhibits reflection bands with both senses of polarization at room temperature. A cholesteric liquid crystal that presents a twist inversion at a critical temperature T(c) is blended with a small quantity of photopolymerizable monomers. Upon ultraviolet irradiation above T(c), the liquid crystal becomes a polymer-stabilized liquid crystal. Below T(c), the material reflects a dual circularly polarized band in the infrared. By quenching the experimental cell at a temperature below the blend's melting point, the optical properties of the material in an undercooled state are conserved for months at room temperature, which is critical to potential applications such as heat-repelling windows and polarization-independent photonic devices.

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. Quantum information processing in localized modes of light within a photonic band-gap material

    CERN Document Server

    Vats, N; John, S; Vats, Nipun; Rudolph, Terry; John, Sajeev

    1999-01-01

    The single photon occupation of a localized field mode within an engineered network of defects in a photonic band-gap (PBG) material is proposed as a unit of quantum information (qubit). Qubit operations are mediated by optically-excited atoms interacting with these localized states of light as the atoms traverse the connected void network of the PBG structure. We describe conditions under which this system can have independent qubits with controllable interactions and very low decoherence, as required for quantum computation.

  5. 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.

  6. Band structure and transport studies of copper selenide: An efficient thermoelectric material

    Science.gov (United States)

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Auluck, S.; Dhar, Ajay

    2014-10-01

    We report the band structure calculations for high temperature cubic phase of copper selenide (Cu2Se) employing Hartree-Fock approximation using density functional theory within the generalized gradient approximation. These calculations were further extended to theoretically estimate the electrical transport coefficients of Cu2Se employing Boltzmann transport theory, which show a reasonable agreement with the corresponding experimentally measured values. The calculated transport coefficients are discussed in terms of the thermoelectric (TE) performance of this material, which suggests that Cu2Se can be a potential p-type TE material with an optimum TE performance at a carrier concentration of ˜ 4 - 6 × 10 21 cm - 3 .

  7. Liquid-crystal photonic-band-gap materials the tunable electromagnetic vacuum

    CERN Document Server

    Busch, K

    1999-01-01

    We demonstrate that when an optically birefringent nematic liquid crystal is infiltrated into the void regions of an inverse opal, photonic-band-gap (PBG) material, the resulting composite material exhibits a completely tunable PBG. $9 In particular, the three- dimensional PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone. Tunable light localization effects may $9 be realized by controlling the orientational disorder in the nematic. (28 refs).

  8. Chemical synthesis of Cd-free wide band gap materials for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sankapal, B.R.; Sartale, S.D.; Ennaoui, A. [Hahn-Meitner-Institut, Berlin (Germany). Department of Solar Energy Research; Lokhande, C.D. [Shivaji University, Kolhapur (India). Department of Physics

    2004-07-01

    Chemical methods are nowadays very attractive, since they are relatively simple, low cost and convenient for larger area deposition of thin films. In this paper, we outline our work related to the synthesis and characterization of some wide band gap semiconducting material thin films prepared by using solution methods, namely, chemical bath deposition and successive ionic layer adsorption and reaction (SILAR). The optimum preparative parameters are given and respective structural, surface morphological, compositional, optical, and electrical properties are described. Some materials we used in solar cells as buffer layers and achieved remarkable results, which are summarized. (author)

  9. Electronic and thermoelectric properties of Mexican hat bands in van-der-Waals materials

    Science.gov (United States)

    Wickramaratne, Darshana; Zahid, Ferdows; Lake, Roger

    2015-03-01

    Mexican hat dispersions are relatively common in few-layer two-dimensional materials. In one to four monolayers of the group-III chalcogenides (GaS, GaSe, InS, InSe) and Bi2Se3 the valence band undergoes a band inversion from a parabolic to an inverted Mexican hat dispersion as the film thickness is reduced from bulk to a single monolayer. The band inversion is robust against changes in stacking order, omission or inclusion of spin-orbit coupling and the choice of functional. The Mexican hat dispersion results in a 1/√{ E} singularity in the two-dimensional density of states and a step-function turn on in the density of modes. The largest radius of the ring of states occurs for a single monolayer of each material. The dispersion with the largest radius coincides with the maximum power factor and ZT for a material at room temperature. Ab-initio electronic structure calculations are used with a Landauer approach to calculate the thermoelectric transport coefficients. Analytical models of the Mexican hat and the parabolic dispersions are used for comparison and analysis. Vertically biased bilayer graphene could serve as an experimental test-bed for measuring this effect since the radius of the Mexican hat band edge increases linearly with vertical electric field. Support by the NSF and SRC-NRI Project 2204.001 (NSF-ECCS-1124733), FAME, one of six centers of STARnet, a SRC program sponsored by MARCO and DARPA and the use of XSEDE NSF Grant # OCI-1053575.

  10. 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.

  11. Controllable Absorption and Dispersion Properties of an RF-driven Five-Level Atom in a Double-Band Photonic-Band-Gap Material

    Institute of Scientific and Technical Information of China (English)

    DING Chun-Ling; LI Jia-Hua; YANG Xiao-Xue

    2011-01-01

    The probe absorption-dispersion spectra of a radio-frequency (RF)-driven five-level atom embedded in a photonic crystal are investigated by considering the isotropic double-band photonic-band-gap (PBG) reservoir. In the model used, the two transitions are, respectively, coupled by the upper and lower bands in such a PBG material, thus leading to some curious phenomena. Numerical simulations are performed for the optical spectra. It is found that when one transition frequency is inside the band gap and the other is outside the gap, there emerge three peaks in the absorption spectra. However, for the case that two transition frequencies lie inside or outside the band gap, the spectra display four absorption profiles. Especially, there appear two sharp peaks in the spectra when both transition frequencies exist inside the band gap. The influences of the intensity and frequency of the RF-driven field on the absorptive and dispersive response are analyzed under different band-edge positions. It is found that a transparency window appears in the absorption spectra and is accompanied by a very steep variation of the dispersion profile by adjusting system parameters. These results show that the absorption-dispersion properties of the system depend strongly on the RFinduced quantum interference and the density of states (DOS) of the PBG reservoir.

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

    DEFF Research Database (Denmark)

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

    For a given doping level a thermoelectric material is optimized for a given temperature. Thermoelectric modules, however, operates over large gradients in temperature. To circumvent this problem we have synthesized a functionally graded thermoelectric material optimized for large temperature...... 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 dopant concentration. Parameters relevant to the thermoelectric properties have been determined along the pulling direction. All of these properties exhibit the wanted gradient. It has thereby been shown that engineering of the electrical contributions to the thermoelectric properties of a material...

  13. Progress of Si-based nanocrystalline luminescent materials

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Si-based nanomaterials are some new photoelctronic and informational materials developed rapidly in recent years, and they have potential applications in the light emitting devices, e. g. Si light emitting diode, Si laser and integrated Si-based photoelectronics. Among them are nanoscale porous silicon (ps), Si nanocrystalline embedded SiO2 (SiOx, x < 2.0) matrices, Si nanoquantum dot and Si/SiO2 superlattice, etc. At present, there are various indications that if these materials can achieve efficient and stable luminescence, which are photoluminescence (PL) and electroluminescence (EL), it is possible for them to lead to a new informational revolution in the early days of the 21st century. In this article, we will mainly review the progress of study on Si-based nanomaterials in the past ten years. The involved contents are the fabricated methods, structural characterizations and light emitting properties. Finally, we predicate the developed tendency of this field in the following ten years.

  14. 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.

  15. 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.

  16. 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.

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

    Science.gov (United States)

    Singh, Avanish Pratap; Anoop Kumar, S.; Chandra, Amita; Dhawan, S. K.

    2011-06-01

    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.

  18. 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.

  19. 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.)

  20. 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)

  1. Application progress of rare earth nano-materials

    Institute of Scientific and Technical Information of China (English)

    Xiao Zhe

    2009-01-01

    @@ Total rare earth consumption exceeded 72,600 tREO domestically in China in 2007, among which over 38,500 tREO were consumed in functional materials like permanent magnetic materials, fluorescent materials, hydrogen storage materials, catalytic materials and polishing powders,representing 53% of total RE consumption. Production and application of RE performance materials have been the main force promoting the development of China rare earth industry.

  2. 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.

  3. 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.

  4. Tunable photonic band-gaps in one-dimensional photonic crystals containing linear graded index material

    Science.gov (United States)

    Singh, Bipin K.; Kumar, Pawan; Pandey, Praveen C.

    2014-12-01

    We have demonstrated control of the photonic band gaps (PBGs) in 1-D photonic crystals using linear graded index material. The analysis of PBG has been done in THz region by considering photonic crystals in the form of ten periods of second, third and fourth generation of the Fibonacci sequence as unit cell. The unit cells are constituted of two kinds of layers; one is taken of linear graded index material and other of normal dielectric material. For this investigation, we used a theoretical model based on transfer matrix method. We have obtained a large number of PBGs and their bandwidths can be tuned by changing the grading profile and thicknesses of linear graded index layers. The number of PBGs increases with increase in the thicknesses of layers and their bandwidths can be controlled by the contrast of initial and final refractive index of the graded layers. In this way, we provide more design freedom for photonic devices such as reflectors, filters, optical sensors, couplers, etc.

  5. Development of imaging arrays for solar UV observations based on wide band gap materials

    Science.gov (United States)

    Schuehle, Udo H.; Hochedez, Jean-Francois E.; Pau, Jose Luis; Rivera, Carlos; Munoz, Elias; Alvarez, Jose; Kleider, Jean-Paul; Lemaire, Philippe; Appourchaux, Thierry; Fleck, Bernhard; Peacock, Anthony; Richter, Mathias; Kroth, Udo; Gottwald, Alexander; Castex, Marie-Claude; Deneuville, Alain; Muret, Pierre; Nesladek, Milos; Omnes, Franck; John, Joachim; Van Hoof, Chris

    2004-02-01

    Solar ultraviolet imaging instruments in space pose most demanding requirements on their detectors in terms of dynamic range, low noise, high speed, and high resolution. Yet UV detectors used on missions presently in space have major drawbacks limiting their performance and stability. In view of future solar space missions we have started the development of new imaging array devices based on wide band gap materials (WBGM), for which the expected benefits of the new sensors - primarily visible blindness and radiation hardness - will be highly valuable. Within this initiative, called "Blind to Optical Light Detectors (BOLD)", we have investigated devices made of AlGa-nitrides and diamond. We present results of the responsivity measurements extending from the visible down to extreme UV wavelengths. We discuss the possible benefits of these new devices and point out ways to build new imaging arrays for future space missions.

  6. Band Gap Tuning in 2D Layered Materials by Angular Rotation

    Directory of Open Access Journals (Sweden)

    Javier Polanco-Gonzalez

    2017-02-01

    Full Text Available We present a series of computer-assisted high-resolution transmission electron (HRTEM simulations to determine Moiré patters by induced twisting effects between slabs at rotational angles of 3°, 5°, 8°, and 16°, for molybdenum disulfide, graphene, tungsten disulfide, and tungsten selenide layered materials. In order to investigate the electronic structure, a series of numerical simulations using density functional methods (DFT methods was completed using Cambridge serial total energy package (CASTEP with a generalized gradient approximation to determine both the band structure and density of states on honeycomb-like new superlattices. Our results indicated metallic transitions when the rotation approached 8° with respect to each other laminates for most of the two-dimensional systems that were analyzed.

  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. 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.

  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. 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.

  11. 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.

  12. 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.

  13. Conversion of sandy tailing from banded iron formation exploitation into glass-ceramic materials

    Directory of Open Access Journals (Sweden)

    Valéria Alves Rodrigues de Melo

    2012-02-01

    Full Text Available Glass-ceramic materials made of 40.0 wt. (% of sandy tailing from banded iron formation exploitation and 60 wt. (% of slag from steelwork were analyzed. Vitrification was obtained by heating the batch samples up to 1400 °C for 1 hour and quenching the melt on a stainless steel plate. Devitrification was obtained by heat-treating the as-quenched glass samples in isothermal conditions at 750 and 1000 °C for 2 hours. FTIR spectroscopy analysis on the devitrified samples indicates a peak shift towards higher wave number with respect to the as-quenched glass because of the crystallization. XRD analysis revealed the presence of crystalline diopside CaMgSi2O6 as the major phase in the glass samples isothermally heat-treated at 1000 °C. Results also indicated that the devitrification at 1000 °C and an incipient devitrification at 750 °C resulted into harder glass-ceramic materials.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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.

  3. 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.

  4. Hypersonic modulation of light in three-dimensional photonic and phononic band-gap materials.

    Science.gov (United States)

    Akimov, A V; Tanaka, Y; Pevtsov, A B; Kaplan, S F; Golubev, V G; Tamura, S; Yakovlev, D R; Bayer, M

    2008-07-18

    The elastic coupling between the a-SiO2 spheres composing opal films brings forth three-dimensional periodic structures which besides a photonic stop band are predicted to also exhibit complete phononic band gaps. The influence of elastic crystal vibrations on the photonic band structure has been studied by injection of coherent hypersonic wave packets generated in a metal transducer by subpicosecond laser pulses. These studies show that light with energies close to the photonic band gap can be efficiently modulated by hypersonic waves.

  5. 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.

  6. 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.

  7. Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals (NBIT Phase II)

    Science.gov (United States)

    2011-05-06

    Final Report for AOARD Grant 1014069 “Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals...NBIT Phase II)” 5 July 2011 Name of Principal Investigators: Edwin L Thomas, Dept of Materials Science and Engineering, MIT e-mail address... elt @mit.edu Institution : Massachusetts Institute of Technology Mailing Address : 77 Mass. Avenue, 6-113, Cambridge, MA 02139 Phone : 617-253-6901

  8. 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.

  9. Progress in Research on Materials Under Microgravity in China

    Institute of Scientific and Technical Information of China (English)

    CHEN Nuofu; CHEN Wanchun; LUO Xinghong; YE Yude

    2004-01-01

    Research on materials under microgravity in China began in the 1980s, sparked by Prof. Lanying Lin (academician of CAS), Prof. Xiji Wang (academician of CAS), Prof. Guirong Min (academician of CAS), and Prof. Huabao Lin (academician of CAS), and others. The first semiconductor crystal, first optical crystal, and first alloys were grown in space on board a recoverable satellite in 1987. Since then, microgravity materials science became a new scientific branch in China.Scientific and technical activities on space crystal growth and solidification are carried out through two major programs: ground-based studies and orbital experiments. The main results obtained during 2001-2003 are reported below.

  10. Recent Progress on PEDOT-Based Thermoelectric Materials

    Directory of Open Access Journals (Sweden)

    Qingshuo Wei

    2015-02-01

    Full Text Available The thermoelectric properties of poly(3,4-ethylenedioxythiophene (PEDOT-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the anisotropic thermoelectric properties. In the last part, we describe our work on improving the power output of thermoelectric modules by using PEDOT, and we outline the potential applications of polymer thermoelectric generators.

  11. 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.

  12. 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).

  13. 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.

  14. 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.

  15. Progress in the research and application of polysaccharide hemostatic materials

    Directory of Open Access Journals (Sweden)

    Yi JIANG

    2015-01-01

    Full Text Available Local hemostasis is the first step in wound treatment, and effective hemostatic methods could reduce the number of unnecessary casualties. Hemostatic materials need to have good hemostatic properties, excellent biocompatibility, no toxic side effects, no irritation and easy to prepare. The polysaccharide has many advantages, including rich source, simple structures, absorbable and biodegradable, excellent biocompatibility. At present, it has been found that polysaccharide is easy to modify in structure and recombine. This paper summarizes the characteristics and products of polysaccharide hemostatic materials including celluloses, chitosans, alginate, hyaluronic acid, and starch in order to offer the indications for clinical application and further study. DOI: 10.11855/j.issn.0577-7402.2014.12.16

  16. Research and Application Progress of Silicone Rubber Materials in Aviation

    Directory of Open Access Journals (Sweden)

    HUANG Yanhua

    2016-06-01

    Full Text Available The research progress of heat resistance, cold resistance, electrical conductivity and damping properties of aviation silicone rubber were reviewed in this article. The heat resistance properties of silicone rubber can be enhanced by changing the molecular structure (main chain, end-group, side chain and molecular weight of the gum and adding special heat-resistance filler. The cold resistance of aviation silicone rubber can be enhanced by adjusting the side chain molecular structure of the gum and the content of different gum chain. The electrical conductivity of silicone rubber can be improved by optimizing, blending and dispersing of conductive particles. The damping property of silicone rubber can be improved by designing and synthesizing of high-molecular polysiloxane damping agent. Furthermore, the application of aviation silicone rubber used in high-low temperature seal, electrical conduction and vibration damping technology are also summarized, and the high performance (for example long-term high temperature resistance, ultralow temperature resistance, high electromagnetic shelding, long-term fatigue resistance vibration damping, quasi constant modulus and so on of special silicone rubber is the future direction of aviation silicone rubber.

  17. 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...

  18. [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.

  19. 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.

  20. 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.'

  1. 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

  2. Research progress on ultra-precision machining technologies for soft-brittle crystal materials

    Science.gov (United States)

    Gao, Hang; Wang, Xu; Guo, Dongming; Chen, Yuchuan

    2016-12-01

    Soft-brittle crystal materials are widely used in many fields, especially optics and microelectronics. However, these materials are difficult to machine through traditional machining methods because of their brittle, soft, and anisotropic nature. In this article, the characteristics and machining difficulties of soft-brittle and crystals are presented. Moreover, the latest research progress of novel machining technologies and their applications for softbrittle crystals are introduced by using some representative materials (e.g., potassium dihydrogen phosphate (KDP), cadmium zinc telluride (CZT)) as examples. This article reviews the research progress of soft-brittle crystals processing.

  3. Progress in Mechanics of Materials by Using Laser Speckle Method

    Science.gov (United States)

    Lagattu, F.; Brillaud, J.; Lafarie-Frenot, M. C.

    The aim of this paper is to present some examples of the use of laser speckle method for the study of composite and polymer mechanical behaviour. A specific mechanical device has been designed in order to realise in-situ singly exposed speckle photographs. It is thus possible to obtain quite rapidly and easily " in-situ " displacement measurements, that is to say on the tensile testing machine, and with a good accuracy. This method has been applied to check and improve mechanical constitutive laws of structural composite materials. It has also been applied to validate new mechanical tests, for example shear tests, by verifying the uniformity of strain fields in the specimens. Moreover, this method allowed us to characterise strain fields around crack tips in polymers.

  4. 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.

  5. Materials research and beam line operation utilizing NSLS. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Liedl, G.L.

    1993-06-01

    MATRIX, a participating research team of Midwest x-ray scattering specialists, continues to operate beam line X-18A at NSLS. Operations of this line now provides state-of-the-art capabilities to a wide range of people in the Materials Science and Engineering research community. Improvements of the beam line continue to be a focus of MATRIX. Throughout this past year the emphasis has been shifting towards improvement in ``user friendly`` aspects. Simplified control operations and a shift to single-user personal computer has been a major part of the effort. Over the past year all 232 operational days were fully utilized. Beam line tests coupled with MATRIX members combined to use 284 days. General user demand for use of the beam line continues to be strong and four groups were provided 48 operating days. Research production has been growing as NSLS and the beam line become a more stable type of operation. For 1992 the MATRIX group published six articles. To date, for 1993 the same group has published, submitted, or has in preparation nine articles. Recent research milestones include: the first quantitative structural information on the as-quenched and early stages of decomposition of supersaturated Al-Li alloys; the first quantitative diffuse scattering measurements on a complex system (Co substitute for Cu YBCO superconductor); demonstration of capabilities of a new UHV surface diffraction chamber with in-situ characterization and temperature control (30-1300K); feasibility of phasing structure factors in a quasicrystal using multiple Bragg scattering.

  6. Quantifying electronic band interactions in van der Waals materials using angle-resolved reflected-electron spectroscopy

    Science.gov (United States)

    Jobst, Johannes; van der Torren, Alexander J. H.; Krasovskii, Eugene E.; Balgley, Jesse; Dean, Cory R.; Tromp, Rudolf M.; van der Molen, Sense Jan

    2016-11-01

    High electron mobility is one of graphene's key properties, exploited for applications and fundamental research alike. Highest mobility values are found in heterostructures of graphene and hexagonal boron nitride, which consequently are widely used. However, surprisingly little is known about the interaction between the electronic states of these layered systems. Rather pragmatically, it is assumed that these do not couple significantly. Here we study the unoccupied band structure of graphite, boron nitride and their heterostructures using angle-resolved reflected-electron spectroscopy. We demonstrate that graphene and boron nitride bands do not interact over a wide energy range, despite their very similar dispersions. The method we use can be generally applied to study interactions in van der Waals systems, that is, artificial stacks of layered materials. With this we can quantitatively understand the `chemistry of layers' by which novel materials are created via electronic coupling between the layers they are composed of.

  7. 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.

  8. 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.

  9. 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.

  10. User-defined Material Model for Thermo-mechanical Progressive Failure Analysis

    Science.gov (United States)

    Knight, Norman F., Jr.

    2008-01-01

    Previously a user-defined material model for orthotropic bimodulus materials was developed for linear and nonlinear stress analysis of composite structures using either shell or solid finite elements within a nonlinear finite element analysis tool. Extensions of this user-defined material model to thermo-mechanical progressive failure analysis are described, and the required input data are documented. The extensions include providing for temperature-dependent material properties, archival of the elastic strains, and a thermal strain calculation for materials exhibiting a stress-free temperature.

  11. 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

  12. Sn-doped CdTe as promising intermediate-band photovoltaic material

    Science.gov (United States)

    Flores, Mauricio A.; Menéndez-Proupin, Eduardo; Orellana, Walter; Peña, Juan L.

    2017-01-01

    The formation energies, charge transition levels and quasiparticle defect states of several tin-related impurities are investigated within the DFT  +  GW formalism. The optical spectrum obtained from the solution of the Bethe-Salpeter equation shows that the absorption strongly increases in the sub-bandgap region after doping, suggesting a two-step photoexcitation process that facilitates transitions from photons with insufficient energy to cause direct transitions from the valence to the conduction band via an intermediate-band. We propose Sn-doped CdTe as a promising candidate for the development of high-efficiency solar cells, which could potentially overcome the Shockley-Queisser limit.

  13. Designer disordered complex media : hyperuniform photonic and phononic band gap materials.

    OpenAIRE

    Amoah, T. K.

    2016-01-01

    In this thesis we investigate designer disordered complex media for photonics and phononics applications. Initially we focus on the photonic properties and we analyse hyperuniform disordered structures (HUDS) using numerical simulations. Photonic HUDS are a new class of photonic solids, which display large, isotropic photonic band gaps (PBG) comparable in size to the ones found in photonic crystals (PC). We review their complex interference properties, including the origin of PBGs and potent...

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Efficient light amplification in low gain materials due to a photonic band edge effect.

    Science.gov (United States)

    Ondič, L; Pelant, I

    2012-03-26

    One of the possibilities of increasing optical gain of a light emitting source is by embedding it into a photonic crystal (PhC). If the properties of the PhC are tuned so that the emission wavelength of the light source with gain falls close to the photonic band edge of the PhC, then due to low group velocity of the light modes near the band edge caused by many multiple reflections of light on the photonic structure, the stimulated emission can be significantly enhanced. Here, we perform simulation of the photonic band edge effect on the light intensity of spectrally broad source interacting with a diamond PhC with low optical gain. We show that even for the case of low gain, up to 10-fold increase of light intensity output can be obtained for the two-dimensional PhC consisting of only 19 periodic layers of infinitely high diamond rods ordered into a square lattice. Moreover, considering the experimentally feasible structure composed of diamond rods of finite height - PhC slab - we show that the gain enhancement, even if reduced compared to the ideal case of infinite rods, still remains relatively high. For this particular structure, we show that up to 3.5-fold enhancement of light intensity can be achieved.

  19. 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.

  20. Soluble narrow band gap and blue propylenedioxythiophene-cyanovinylene polymers as multifunctional materials for photovoltaic and electrochromic applications.

    Science.gov (United States)

    Thompson, Barry C; Kim, Young-Gi; McCarley, Tracy D; Reynolds, John R

    2006-10-04

    A family of soluble narrow band gap donor-acceptor conjugated polymers based on dioxythiophenes and cyanovinylenes is reported. The polymers were synthesized using Knoevenagel polycondensation or Yamamoto coupling polymerizations to yield polymers with molecular weights on the order of 10 000-20 000 g/mol, which possess solubility in common organic solvents. Thin film optical measurements revealed narrow band gaps of 1.5-1.8 eV, which gives the polymers a strong overlap of the solar spectrum. The energetic positions of the band edges were determined by cyclic voltammetry and differential pulse voltammetry and demonstrate that the polymers are both air stable and show a strong propensity for photoinduced charge transfer to fullerene acceptors. Such measurements also suggest that the polymers can be both p- and n-type doped, which is supported by spectroelectrochemical results. These polymers have been investigated as electron donors in photovoltaic devices in combination with PCBM ([6,6]-phenyl C(61)-butyric acid methyl ester) as an electron acceptor based on the near ideal band structures designed into the polymers. Efficiencies as high as 0.2% (AM1.5) with short circuit current densities as high as 1.2-1.3 mA/cm(2) have been observed in polymer/PCBM (1:4 by weight) devices and external quantum efficiencies of more than 10% have been observed at wavelengths longer than 600 nm. The electrochromic properties of the narrow band gap polymers are also of interest as the polymers show three accessible color states changing from an absorptive blue or purple in the neutral state to a transmissive sky-blue or gray in the oxidized and reduced forms. The wide electrochemical range of electrochromic activity coupled with the strong observed changes in transmissivity between oxidation states makes these materials potentially interesting for application to electrochromic displays.

  1. 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. ...

  2. 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)

  3. Full-band structure modeling of the radiative and non-radiative properties of semiconductor materials and devices (Presentation Recording)

    Science.gov (United States)

    Bellotti, Enrico; Wen, Hanqing; Pinkie, Benjamin; Matsubara, Masahiko; Bertazzi, Francesco

    2015-08-01

    Understanding the radiative and non-radiative properties of semiconductor materials is a prerequisite for optimizing the performance of existing light emitters and detectors and for developing new device architectures based on novel materials. Due to the ever increasing complexity of novel semiconductor systems and their relative technological immaturity, it is essential to have design tools and simulation strategies that include the details of the microscopic physics and their dependence on the macroscopic (continuum) variables in the macroscopic device models. Towards this end, we have developed a robust full-band structure based approach that can be used to study the intrinsic material radiative and non-radiative properties and evaluate the same characteristics of low-dimensional device structures. A parallel effort is being carried out to model the effect of substrate driven stress/strain and material quality (dislocations and defects) on microscopic quantities such as non-radiative recombination rate. Using this modeling approach, we have extensively studied the radiative and non-radiative properties of both elemental (Si and Ge) and compound semiconductors (HgCdTe, InGaAs, InAsSb and InGaN). In this work we outline the details of the modelling approach, specifically the challenges and advantages related to the use of the full-band description of the material electronic structure. We will present a detailed comparison of the radiative and Auger recombination rates as a function of temperature and doping for HgCdTe and InAsSb that are two important materials for infrared detectors and emitters. Furthermore we will discuss the role of non-radiatiave Auger recombination processes in explaining the performance of light emitter diodes. Finally we will present the extension of the model to low dimensional structures employed in a number of light emitter and detector structures.

  4. Investigation of dust bands from blue ice fields in the Lewis Cliff (Beardmore) area, Antarctica: A progress report

    OpenAIRE

    Koeberl, Christian; Yanai,Keizo; Cassidy, William A.; Schutt,John W.

    1988-01-01

    Blue ice fields in Antarctica are well known for their high areal meteorite concentrations. The exact type of accumulation model and the age of the ice is still not well known. Dust bands on blue ice fields may help to clarify some of these problems. Dust, which has been isolated from dust band samples from blue ice areas in the Lewis Cliff/Walcott Neve area (Beardmore region), Antarctica, was studied to determine petrographic characteristics and chemical compositions. One sample has an avera...

  5. Enhancement of band-to-band tunneling in mono-layer transition metal dichalcogenides two-dimensional materials by vacancy defects

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiang-Wei; Li, Shu-Shen [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Gong, Jian [School of Physics Science and Technology, Inner Mongolia University, Hohhot 010021 (China); Xu, Nuo [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Zhang, Jinfeng; Hao, Yue [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-01-13

    The band-to-band tunneling of monolayer transition metal dichalcogenides nano-junction is investigated using atomistic ab initio quantum transport simulations. From the simulation, it is found that the transition metal vacancy defect in the two-dimensional MX{sub 2} (M = Mo,W; X = S,Se) band-to-band tunneling diode can dramatically boost the on-state current up to 10 times while maintaining the device sub-threshold swing. The performance enhancement mechanism is discussed in detail by examining partial density of states of the system. It is found that the transition metal vacancy induces band-gap states, which reduce the effective length of the tunneling transition region.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1991-07-01

    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.

  14. Recent progress of dopant-free organic hole-transporting materials in perovskite solar cells

    Science.gov (United States)

    Dongxue, Liu; Liu, Yongsheng

    2017-01-01

    Organic–inorganic hybrid perovskite solar cells have undergone especially intense research and transformation over the past seven years due to their enormous progress in conversion efficiencies. In this perspective, we review the latest developments of conventional perovskite solar cells with a main focus on dopant-free organic hole transporting materials (HTMs). Regarding the rapid progress of perovskite solar cells, stability of devices using dopant-free HTMs are also discussed to help readers understand the challenges and opportunities in high performance and stable perovskite solar cells. Project supported by the Scientific Research Starting Foundation for Overseas Introduced Talents of College of Chemistry, Nankai University.

  15. Metals and Ceramics Division materials science annual progress report for period ending June 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1977-09-01

    Progress is reported for research programs in the metals and ceramics division of ORNL. In structure of materials, theoretical research, x-ray diffraction studies, studies of erosion of ceramics, preparation and synthesis of high temperature and special service materials, and studies of stabilities of microphases in high-temperature structural materials. Research into deformation and mechanical properties included physical metallurgy, and grain boundary segregation and embrittlement. Physical properties and transport phenomena were studied and included mechanisms of surface and solid state reactions, and properties of superconducting materials. The radiation effects program, directed at understanding the effects of composition and microstructure on the structure and properties of materials irradiated at elevated temperatures, is also described. (GHT)

  16. 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.

  17. The study of below and above band-edge imperfection states in In2S3 solar energy materials

    Science.gov (United States)

    Ho, Ching-Hwa

    2012-08-01

    β-In2S3 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 β-In2S3 has also been proposed to increase conversion efficiency in In2S3 since multi-photons absorption by intermediate band (IB) would happen in the sulfide. In this paper, single crystals of undoped and Nb-doped β-In2S3 have been grown by the chemical vapor transport (CVT) method using ICl3 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 β-In2S3 are direct semiconductors with energy gap of 1.935 eV for undoped β-In2S3, 1.923 eV for β-In2S3:Nb0.005, and 1.901 eV for β-In2S3:Nb0.01. For undoped β-In2S3, PC and PL measurements are used to characterize defect transitions below band gap. The above band-edge transitions of undoped β-In2S3 have also been evaluated using PL, PC, and SPR measurements. For the evaluation of Nb-doped β-In2S3, an intermediate band with energy of ∼0.4 eV below the conduction band edge has been detected in the TR measurements in both β-In2S3:Nb0.005 and β-In2S3:Nb0.01. The photo V-I measurements also verified that the photoelectric-conversion efficiency would be enhanced in the β-In2S3 with higher niobium content. Based on the experimental analyses, the optical behavior of the defects, surface states, and IB (formed by Nb) in the In2S3 crystals is thus explored.

  18. Recent progress in nickel based materials for high performance pseudocapacitor electrodes

    Science.gov (United States)

    Feng, Liangdong; Zhu, Yufu; Ding, Hongyan; Ni, Chaoying

    2014-12-01

    Nickel based materials have been intensively investigated and considered as good potential electrode materials for pseudocapacitors due to their high theoretical specific capacity values, high chemical and thermal stability, ready availability, environmentally benign nature and lower cost. This review firstly examines recent progress in nickel oxides or nickel hydroxides for high performance pseudocapacitor electrodes. The advances of hybrid electrodes are then assessed to include hybrid systems of nickel based materials with compounds such as carbonaceous materials, metal and transition metal oxides or hydroxides, in which various strategies have been adopted to improve the electrical conductivity of nickel oxides or hydroxides. Furthermore, the energy density and power density of some recently reported NiO, nickel based composites and NiCo2O4 are summarized and discussed. Finally, we provide some perspectives as to the future directions of this intriguing field.

  19. [Application progress of laser-induced breakdown spectroscopy for surface analysis in materials science field].

    Science.gov (United States)

    Zhang, Yong; Jia, Yun-Hai; Chen, Ji-Wen; Liu, Ying; Shen, Xue-Jing; Zhao, Lei; Wang, Shu-Ming; Yu, Hong; Han, Peng-Cheng; Qu, Hua-Yang; Liu, Shao-Zun

    2012-06-01

    As a truly surface analytical tool, laser-induced breakdown spectroscopy (LIBS) was developed in recent ten years, and in this paper, fundamental theory, instrumentation and it's applications in material science are reviewed in detail. Application progress of elemental distribution and depth profile analysis are mainly discussed in the field of metallurgy, semiconductor and electronical materials at home and abroad. It is pointed out that the pulse energy, ambient gas and it's pressure, and energy distribution of laser beam strongly influence spatial and depth resolution, and meanwhile a approach to improving resolution considering analytical sensitivity is provided. Compared with traditional surface analytical methods, the advantage of LIBS is very large scanning area, high analytical speed, and that conducting materials or non-conducting materials both can be analyzed. It becomes a powerful complement of traditional surface analytical tool.

  20. 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

  1. 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.

  2. Band Gap Engineering of Boron Nitride by Graphene and Its Application as Positive Electrode Material in Asymmetric Supercapacitor Device.

    Science.gov (United States)

    Saha, Sanjit; Jana, Milan; Khanra, Partha; Samanta, Pranab; Koo, Hyeyoung; Murmu, Naresh Chandra; Kuila, Tapas

    2015-07-08

    Nanostructured hexagonal boron nitride (h-BN)/reduced graphene oxide (RGO) composite is prepared by insertion of h-BN into the graphene oxide through hydrothermal reaction. Formation of the super lattice is confirmed by the existence of two separate UV-visible absorption edges corresponding to two different band gaps. The composite materials show enhanced electrical conductivity as compared to the bulk h-BN. A high specific capacitance of ∼824 F g(-1) is achieved at a current density of 4 A g(-1) for the composite in three-electrode electrochemical measurement. The potential window of the composite electrode lies in the range from -0.1 to 0.5 V in 6 M aqueous KOH electrolyte. The operating voltage is increased to 1.4 V in asymmetric supercapacitor (ASC) device where the thermally reduced graphene oxide is used as the negative electrode and the h-BN/RGO composite as the positive electrode. The ASC exhibits a specific capacitance of 145.7 F g(-1) at a current density of 6 A g(-1) and high energy density of 39.6 W h kg(-1) corresponding to a large power density of ∼4200 W kg(-1). Therefore, a facile hydrothermal route is demonstrated for the first time to utilize h-BN-based composite materials as energy storage electrode materials for supercapacitor applications.

  3. 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.

  4. 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.

  5. 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.

  6. Science of materials. Progress report, July 1, 1977--June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-04-01

    Progress is reported in research which includes studies of the deformation, stress corrosion and fracture of alloys and geologic materials with emphasis on hydrogen embrittlement of metals; the mechanism of heat transfer across interfaces; 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 ionic conduction, phase transitions and radiation damage. Ferro- and pyroelectric materials with potential for solar energy applications are under development. The study of optical properties includes the mechanism of luminescence and new semiconductor materials for photovoltaic devices. The electronic properties of crystals are the subject of a continued effort to resolve current problems of magnetic behavior and photon-solid interactions. Specific quantum properties of matter are explored with emphasis on superconductivity, diffusion of hydrogen in metals and the properties of solid helium.

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

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Brinkman, C.R.

    1981-01-01

    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.

  8. 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.

  9. 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.

  10. THE EFFECTS OF EDGE BANDING THICKNESS OF ULUDAG FIR BONDED WITH SOME ADHESIVES ON WITHDRAWAL STRENGTHS OF BEECH DOWEL PINS IN COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    Şeref Kurt

    2009-11-01

    Full Text Available Composite materials and wooden dowels are being used increasingly in the construction of furniture frames and inner decoration. Yet there is little information available concerning the withdrawal strength of various fasteners, and, in particular, dowels in composite materials edged solid wood edge bandings. The aim of this study was to determine the withdrawal strengths of 6, 8, 10 mm diameter dowels produced from beech with respect to edge of a medium-density fiberboard (MDF or particleboard (PB edged with 5, 10 and 15 mm thickness of solid wood edge banding of uludag fir, bonded with different adhesives. According to TS 4539 standard, the effects of edge banding thickness, dimension of dowels, type of composite materials and type of adhesives used for edge banding on the withdrawal strength were determined. The highest (6.37 N/mm² withdrawal strength was obtained in beech dowels with 8 mm diameter for MDF with 5 mm thickness of solid wood edge banding of uludag fir bonded with D-VTKA adhesive. According to results, if the hole wall and the surface of dowel are smooth then the adhesives give better mechanical adhesion with dowels and composite materials.

  11. 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...

  12. 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.

  13. Progress in Materials and Component Development for Advanced Lithium-ion Cells for NASA's Exploration Missions

    Science.gov (United States)

    Reid, Concha, M.; Reid, Concha M.

    2011-01-01

    Vehicles and stand-alone power systems that enable the next generation of human missions to the Moon will require energy storage systems that are safer, lighter, and more compact than current state-of-the- art (SOA) aerospace quality lithium-ion (Li-ion) batteries. NASA is developing advanced Li-ion cells to enable or enhance the power systems for the Altair Lunar Lander, Extravehicular Activities spacesuit, and rovers and portable utility pallets for Lunar Surface Systems. Advanced, high-performing materials are required to provide component-level performance that can offer the required gains at the integrated cell level. Although there is still a significant amount of work yet to be done, the present state of development activities has resulted in the synthesis of promising materials that approach the ultimate performance goals. This report on interim progress of the development efforts will elaborate on the challenges of the development activities, proposed strategies to overcome technical issues, and present performance of materials and cell components.

  14. Recent progress in high-mobility thin-film transistors based on multilayer 2D materials

    Science.gov (United States)

    Hong, Young Ki; Liu, Na; Yin, Demin; Hong, Seongin; Kim, Dong Hak; Kim, Sunkook; Choi, Woong; Yoon, Youngki

    2017-04-01

    Two-dimensional (2D) layered semiconductors are emerging as promising candidates for next-generation thin-film electronics because of their high mobility, relatively large bandgap, low-power switching, and the availability of large-area growth methods. Thin-film transistors (TFTs) based on multilayer transition metal dichalcogenides or black phosphorus offer unique opportunities for next-generation electronic and optoelectronic devices. Here, we review recent progress in high-mobility transistors based on multilayer 2D semiconductors. We describe the theoretical background on characterizing methods of TFT performance and material properties, followed by their applications in flexible, transparent, and optoelectronic devices. Finally, we highlight some of the methods used in metal-semiconductor contacts, hybrid structures, heterostructures, and chemical doping to improve device performance.

  15. 新型吸波材料研究进展%Research Progress on Novel Wave-Absorbing Materials

    Institute of Scientific and Technical Information of China (English)

    孙志岗; 乔小晶; 任庆国; 李旺昌

    2013-01-01

    以铁氧体复合吸波材料为例,概述了吸波材料发展趋势;介绍了两种新型隐身材料(碳纳米管复合吸波材料和左手材料)的发展现状,并对我国吸波材料的发展提出一些建议.%This paper summarizes the current situation of the development of wave-absorbing materials.And the novel wave-absorbing materials are laid a strong emphasis,which requires light,thin,broad-band and strong materials,such as nano-materials and the left-handed materials.Moreover,the developing trend on novel wave-absorbing materials is prospected.Further more,some suggestions have been provided for the development of the novel wave-absorbing materials in the future.

  16. 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.

  17. Discovery of high-performance low-cost n-type Mg3Sb2-based thermoelectric materials with multi-valley conduction bands

    Science.gov (United States)

    Zhang, Jiawei; Song, Lirong; Pedersen, Steffen Hindborg; Yin, Hao; Hung, Le Thanh; Iversen, Bo Brummerstedt

    2017-01-01

    Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost n-type material, Te-doped Mg3Sb1.5Bi0.5, that exhibits a very high figure of merit zT ranging from 0.56 to 1.65 at 300-725 K. Using combined theoretical prediction and experimental validation, we show that the high thermoelectric performance originates from the significantly enhanced power factor because of the multi-valley band behaviour dominated by a unique near-edge conduction band with a sixfold valley degeneracy. This makes Te-doped Mg3Sb1.5Bi0.5 a promising candidate for the low- and intermediate-temperature thermoelectric applications.

  18. The Effects of Rolling Resistance on the Formation of Shear Bands for Granular Materials%滚动机制对颗粒材料剪切带形成的影响

    Institute of Scientific and Technical Information of China (English)

    唐洪祥; 董益峰; 张兴

    2014-01-01

    The macroscopic definition of effective strain was introduced to describe the emergence and development of shear bands in granular materials .Three different numerical tests (i .e .,free rolling test ,limiting rolling test and rolling resistance considered test ) using the discrete element method (DEM ) were conducted to simulate the mechanical response of granular specimens under stress .The progressive development of effective strain in the granular specimens was illus-trated to analyse the origination and evolution of shear bands .The results indicate that the evolution of shear bands in granular materials can be simulated more accurately in free rolling and rolling resistance considered tests ,while be hardly simulated when particle rolling is strictly prevented .In the case of particle rolling resistance ,the shear band evolution is more distinct as the evolution of the minor shear bands is limited while the major shear bands are preferably promoted .%从宏观角度引入颗粒集合体有效应变表述颗粒材料剪切带的形成,从细观上模拟颗粒材料自由滚动、限制滚动、考虑滚动机制三种情况在外荷载下的力学响应。通过分析追踪颗粒材料有效应变的变化,探讨了颗粒材料剪切带的发展和形成过程。结果表明:限制滚动下不能模拟剪切带的发展,考虑颗粒自由滚动及滚动机制能较好的模拟剪切带的发展。而强调滚动机制限制了次要剪切带,同时促进主要剪切带的发展,因而能更有效的描述剪切带的形成过程。

  19. Progress in Overcoming Materials Challenges with S-CO2 RCBCs

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Matthew S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Chemistry Group; Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Chemistry Group; Weck, Philippe F. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Storage and Transportation Technologies Group; Withey, Elizabeth Ann [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Chemistry Group; Fleming, Darryn D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Advanced Nuclear Concepts Group

    2016-09-01

    The supercritical carbon dioxide (S-CO2) Brayton Cycle has gained significant attention in the last decade as an advanced power cycle capable of achieving high efficiency power conversion. Sandia National Laboratories, with support from the U.S. Department of Energy Office of Nuclear Energy (US DOE-NE), has been conducting research and development in order to deliver a technology that is ready for commercialization. There are a wide range of materials-related challenges that must be overcome to ensure the success of this technology. At Sandia, recent work has focused on the following main areas: (1) Investigating the potential for system cost reduction through the introduction of low-cost alloys in low temperature loop sections; (2) identifying material options for 10MW RCBC systems; (3) understanding and resolving turbine degradation; (4) identifying gas foil bearing behavior in CO2; and (5) identifying the influence of gas chemistry on alloy corrosion. Progress in each of these areas is detailed in this report.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

    2015-08-07

    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

  5. Hybrid functionals with fixed mixing parameter perform no better than PBE for fundamental band gaps of nanoscale materials

    Science.gov (United States)

    Wang, Xinquan; Dvorac, Marc; Wu, Zhigang

    2016-11-01

    Hybrid functionals mixing the exact exchange with (semi)local functionals to reinstall the missing derivative discontinuity have been successfully employed to predict band gaps (Eg) in bulk semiconductors. Here we show that traditional hybrid functionals with fixed fractions of exact exchange do not perform significantly better than the most popular semilocal PBE-GGA functional for Eg of semiconductor nanostructures, since their band-gap corrections are essentially size independent. This is because they cannot respond properly to the variation in screening when size changes. They merely predict constant band-gap corrections to the PBE gaps in silicon nanowires (Si NWs) when wire diameter reduces, instead of the dramatic increase predicted by many-body G W calculations. Moreover, these hybrid functionals generate almost identical wave functions compared with PBE for both bulk Si and Si NWs, whose overlaps with corresponding quasiparticle wave functions become much smaller than 1 for narrow NWs.

  6. 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.

  7. Metal finishing and vacuum processes groups, Materials Fabrication Division progress report, March-May 1984

    Energy Technology Data Exchange (ETDEWEB)

    Dini, J.W.; Romo, J.G.; Jones, L.M.

    1984-07-11

    Progress is reported in fabrication and coating activities being conducted for the weapons program, nuclear test program, nuclear design program, magnetic fusion program, and miscellaneous applications. (DLC)

  8. 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.

  9. 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.

  10. 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.

  11. New Material Transistor with Record-High Field-Effect Mobility among Wide-Band-Gap Semiconductors.

    Science.gov (United States)

    Shih, Cheng Wei; Chin, Albert

    2016-08-03

    At an ultrathin 5 nm, we report a new high-mobility tin oxide (SnO2) metal-oxide-semiconductor field-effect transistor (MOSFET) exhibiting extremely high field-effect mobility values of 279 and 255 cm(2)/V-s at 145 and 205 °C, respectively. These values are the highest reported mobility values among all wide-band-gap semiconductors of GaN, SiC, and metal-oxide MOSFETs, and they also exceed those of silicon devices at the aforementioned elevated temperatures. For the first time among existing semiconductor transistors, a new device physical phenomenon of a higher mobility value was measured at 45-205 °C than at 25 °C, which is due to the lower optical phonon scattering by the large SnO2 phonon energy. Moreover, the high on-current/off-current of 4 × 10(6) and the positive threshold voltage of 0.14 V at 25 °C are significantly better than those of a graphene transistor. This wide-band-gap SnO2 MOSFET exhibits high mobility in a 25-205 °C temperature range, a wide operating voltage of 1.5-20 V, and the ability to form on an amorphous substrate, rendering it an ideal candidate for multifunctional low-power integrated circuit (IC), display, and brain-mimicking three-dimensional IC applications.

  12. Recent progress on nanostructured 4 V cathode materials for Li-ion batteries for mobile electronics

    OpenAIRE

    Xiaodong Xu; Sanghan Lee; Sookyung Jeong; Youngsik Kim; Jaephil Cho

    2013-01-01

    Mobile electronics have developed so rapidly that battery technology has hardly been able to keep pace. The increasing desire for lighter and thinner Li-ion batteries with higher capacities is a continuing and constant goal for in research. Achieving higher energy densities, which is mainly dependent on cathode materials, has become a critical issue in the development of new Li-ion batteries. In this review, we will outline the progress on nanostructured 4 V cathode materials of Li-ion batter...

  13. Recent progress on nanostructured 4 V cathode materials for Li-ion batteries for mobile electronics

    Directory of Open Access Journals (Sweden)

    Xiaodong Xu

    2013-12-01

    Full Text Available Mobile electronics have developed so rapidly that battery technology has hardly been able to keep pace. The increasing desire for lighter and thinner Li-ion batteries with higher capacities is a continuing and constant goal for in research. Achieving higher energy densities, which is mainly dependent on cathode materials, has become a critical issue in the development of new Li-ion batteries. In this review, we will outline the progress on nanostructured 4 V cathode materials of Li-ion batteries for mobile electronics, covering LiCoO2, LiNixCoyMn1−x−yO2, LiMn2O4, LiNi0.5Mn1.5O4 and Li-rich layered oxide materials. We aim to provide some scientific insights into the development of superior cathode materials by discussing the advantages of nanostructure, surface-coating, and other key properties.

  14. SOME PROGRESS IN NANOSTRUCTURED LUMINESCENT MATERIALS%纳米发光材料研究的若干进展

    Institute of Scientific and Technical Information of China (English)

    周永慧; 林君; 张洪杰

    2001-01-01

    本文综述了纳米发光材料的研究进展情况,着重总结了(稀土)掺杂型纳米发光材料的制备方法和表征手段,同时介绍了这些纳米发光材料的性质和应用,并对其未来发展趋势进行了展望。%The progress in nanostructured luminescent materials has been reviewed in this paper.Emphases are laid on the synthesis and characterization methods of (rare earth) doped nanostructured luminescent materials.In the meanwhile,the properties and applications of the nanostructured luminescent materials are introduced,and the future development trends for the nanostructured luminescent materials are forecasted in brief.

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

    Science.gov (United States)

    Rasmussen, Filip A.; Schmidt, Per S.; Winther, Kirsten T.; Thygesen, Kristian S.

    2016-10-01

    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 sampling of the Brillouin zone (BZ) than is necessary for similar three-dimensional solids. Here, we use an analytical expression for the small q limit of the 2D response function to perform the BZ integral over the critical region around q =0 . This drastically reduces the requirements on the q -point mesh and implies a significant computational speedup. For example, in the case of monolayer MoS2, convergence of the G0W0 band gap to within ˜0.1 eV is achieved with 12 ×12 q points rather than the 36 ×36 mesh required with discrete BZ sampling techniques. We perform a critical assessment of the band gap of the three prototypical 2D semiconductors, MoS2, h -BN, and phosphorene, including the effect of self-consistency at the GW0 level. The method is implemented in the open source code gpaw.

  16. 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.

  17. Irradiation effects on reactor structural materials. Quarterly progress report, May--July 1965

    Energy Technology Data Exchange (ETDEWEB)

    None

    1965-08-01

    This document contains reports of the following laboratories: Argonne, Battelle, Brookhaven, General Atomic Division, Materials Research Lab., Naval Research Lab., Nuclear Materials and Propulsion Operation, ORNL, Pacific Northwest Lab., and Phillips Petroleum Co. (DLC)

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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)

  3. 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)

  4. The advantage of linear viscoelastic material behavior in passive damper design-with application in broad-banded resonance dampers for industrial high-precision motion stages

    Science.gov (United States)

    Verbaan, Cornelis A. M.; Peters, Gerrit W. M.; Steinbuch, Maarten

    2017-01-01

    In this paper we demonstrate the advantage of applying viscoelastic materials instead of purely viscous materials as damping medium in mechanical dampers. Although the loss modulus decreases as function of frequency in case of viscoelastic behavior, which can be interpreted as a decrease of damping, the viscoelastic behavior still leads to an increased modal damping for mechanical structures. This advantage holds for inertial-mass-type dampers that are tuned for broad-banded resonance damping. It turns out that an increase of the storage modulus as function of frequency contributes to the effectiveness of mechanical dampers with respect to energy dissipation at different mechanical resonance frequencies. It is shown that this phenomenon is medium specific and is independent of the amount of damper mass.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1984-11-01

    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.

  10. 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.

  11. 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

  12. 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.

  13. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1983-05-01

    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.

  15. Progress in the material development of LiCaAlF(6):Cr(3+) laser crystals

    Science.gov (United States)

    Shinn, M. D.; Chase, L. L.; Caird, J. A.; Payne, S. A.; Atherton, L. J.; Kway, W. L.

    1990-03-01

    High Cr(3+) doping levels, up to 8 mole percent, and low losses were obtained with the tunable solid-state laser material LiCaAlF(6):Cr(3+) (Cr:LiCAF). Measurements and calculations show that high pumping and extraction efficiencies are possible with the improved material.

  16. 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)

  17. 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.

  18. 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.

  19. Progress in 3D Printing of Carbon Materials for Energy-Related Applications.

    Science.gov (United States)

    Fu, Kun; Yao, Yonggang; Dai, Jiaqi; Hu, Liangbing

    2017-03-01

    The additive-manufacturing (AM) technique, known as three-dimensional (3D) printing, has attracted much attention in industry and academia in recent years. 3D printing has been developed for a variety of applications. Printable inks are the most important component for 3D printing, and are related to the materials, the printing method, and the structures of the final 3D-printed products. Carbon materials, due to their good chemical stability and versatile nanostructure, have been widely used in 3D printing for different applications. Good inks are mainly based on volatile solutions having carbon materials as fillers such as graphene oxide (GO), carbon nanotubes (CNT), carbon blacks, and solvent, as well as polymers and other additives. Studies of carbon materials in 3D printing, especially GO-based materials, have been extensively reported for energy-related applications. In these circumstances, understanding the very recent developments of 3D-printed carbon materials and their extended applications to address energy-related challenges and bring new concepts for material designs are becoming urgent and important. Here, recent developments in 3D printing of emerging devices for energy-related applications are reviewed, including energy-storage applications, electronic circuits, and thermal-energy applications at high temperature. To close, a conclusion and outlook are provided, pointing out future designs and developments of 3D-printing technology based on carbon materials for energy-related applications and beyond.

  20. 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.

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

    Science.gov (United States)

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-08-01

    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.

  2. 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.

  3. 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...

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

    DEFF Research Database (Denmark)

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

    on the basic of their advantages over chemical and thermal robustness, nontoxic and cheap composed elements. Among oxide materials, layered-cobaltites such as NaCo2O4 and Ca3Co4O9 have recently attracted much attention due to their unusual high TE figure of merit with single crystals, ZT ≈ 1 at 1000 K (ZT = S2......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......σT/κ , where S, σ, T and κ are the Seebeck coefficient, electrical conductivity, absolute temperature and thermal conductivity, respectively). We have fabricated high-quality oxide TE materials based on Ca3Co4O9 by optimizing the method for synthesis, modifying the compositions...

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

    Energy Technology Data Exchange (ETDEWEB)

    Truhan, J.J.; Hopper, R.W.; Gordon, K.M. (eds.)

    1980-10-28

    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. Advances in materials science, Metals and Ceramics Division. Quarterly progress report, July-September 1979

    Energy Technology Data Exchange (ETDEWEB)

    Truhan, J.J.; Weld, F.N.

    1979-10-25

    Research is reported on materials for magnetic fusion energy, laser fusion energy, Al-air batteries, geothermal energy, oil shale, nuclear waste management, thermochemical cycles for hydrogen production, chemistry, and basic energy science. (FS)

  7. 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.

  8. Recent progress in theoretical and computational investigations of Li-ion battery materials and electrolytes

    OpenAIRE

    Bhatt, Mahesh Datt; O'Dwyer, Colm

    2015-01-01

    There is an increasing worldwide demand for high energy density batteries. In recent years, rechargeable Li-ion batteries have become important power sources, and their performance gains are driving the adoption of electrical vehicles (EV) as viable alternatives to combustion engines. The exploration of new Li-ion battery materials is an important focus of materials scientists and computational physicists and chemists throughout the world. The practical applications of Li-ion batteries and em...

  9. 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.

  10. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, October 1, 1979-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-04-18

    This report presents the results of work performed from October 1, 1979 through December 31, 1979. 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, weight gain and post-exposure mechanical properties for materials thermally exposed at 750/sup 0/ and 850/sup 0/C (1382/sup 0/ and 1562/sup 0/F). In addition, the status of the data management system is described.

  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. Research Progress of Dielectric Materials for Energy Storage%电介质储能材料研究进展

    Institute of Scientific and Technical Information of China (English)

    顾逸韬; 刘宏波; 马海华; 童苑馨

    2015-01-01

    The physical basis of energy storage in dielectrics and main test methods were introduced, and the research progress of dielectric materials for energy storage was analyzed and compared. It was found that for the ceramic materials, the research focused on increasing breakdown strength. For the glass and polymer materials, the research focused on increasing permittivity. Preparing two-phase composite material is the research hotspot of dielectric materials for energy storage at present, and the key problem is to control the interface for improving the energy storage density.%介绍了电介质储能的物理基础和主要测试方法,比较分析了各种电介质储能材料的研究进展。在单相电介质材料中,对于陶瓷材料,研究重点是提高击穿场强;对于玻璃、聚合物材料,研究重点是提高介电常数。通过制备两相复合材料提高储能密度是当前电介质储能材料的研究热点,其中的重点问题是如何更好的控制两相界面来提高储能密度。

  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. Nanocrystalline ZnON; High mobility and low band gap semiconductor material for high performance switch transistor and image sensor application

    Science.gov (United States)

    Lee, Eunha; Benayad, Anass; Shin, Taeho; Lee, HyungIk; Ko, Dong-Su; Kim, Tae Sang; Son, Kyoung Seok; Ryu, Myungkwan; Jeon, Sanghun; Park, Gyeong-Su

    2014-01-01

    Interest in oxide semiconductors stems from benefits, primarily their ease of process, relatively high mobility (0.3–10 cm2/vs), and wide-bandgap. However, for practical future electronic devices, the channel mobility should be further increased over 50 cm2/vs and wide-bandgap is not suitable for photo/image sensor applications. The incorporation of nitrogen into ZnO semiconductor can be tailored to increase channel mobility, enhance the optical absorption for whole visible light and form uniform micro-structure, satisfying the desirable attributes essential for high performance transistor and visible light photo-sensors on large area platform. Here, we present electronic, optical and microstructural properties of ZnON, a composite of Zn3N2 and ZnO. Well-optimized ZnON material presents high mobility exceeding 100 cm2V−1s−1, the band-gap of 1.3 eV and nanocrystalline structure with multiphase. We found that mobility, microstructure, electronic structure, band-gap and trap properties of ZnON are varied with nitrogen concentration in ZnO. Accordingly, the performance of ZnON-based device can be adjustable to meet the requisite of both switch device and image-sensor potentials. These results demonstrate how device and material attributes of ZnON can be optimized for new device strategies in display technology and we expect the ZnON will be applicable to a wide range of imaging/display devices. PMID:24824778

  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. 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.

  17. 材料基因组技术前沿进展%Progress on Materials Genome Technology

    Institute of Scientific and Technical Information of China (English)

    向勇; 闫宗楷; 朱焱麟; 张晓琨

    2016-01-01

    Materials genome is an emerging technology to accelerate materials discovery, development, and deployment. In the past two decades, high-throughput materials experimentation tools have been developed and applied successfully to the discovery of a number of materials, ranging from advanced catalysts, dielectrics, electrodes, to high-temperature alloys. Materials computation and database technologies have also made remarkable progresses, particularly represented by the integrated computational materials engineering (ICME) developed in the past decade. Materials genome research integrates high-throughput computation and simulation, high-throughput experimentation, and materials database, throughout the materials discovery-to-deployment process, targeting to cut the materials development time and cost significantly. This review, is trying to give a brief and comprehensive introduction to materials genome technologies, with emphasis on high-throughput materials experimentation, as well as applications of materials computation and database. University of Electronics Science and Technology of China is one of the most active institutes in China in the filed of materials genome research, and some progresses are also highlighted in this review.%材料基因组技术是近年来兴起的材料研究新理念和新方法,是当今世界材料科学与工程领域的最前沿。材料基因组技术的实质是通过融合高通量材料计算设计、高通量材料实验和材料数据库三大组成要素,构建材料设计研发的协同创新网络,加速新材料从发现到应用的全过程。其中,高通量材料实验经过20多年的发展,目前已面向多种形态材料和多种服役性能形成了一系列成功案例,高通量材料计算模拟和材料数据库近几年也取得了较大进展。该文简要回顾了材料基因组技术的主要内容和发展历程,总结了具有代表性的高通量实验技术,以及高通

  18. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, September 23, 1976--December 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    This report presents the results of work performed from September 23, 1976 through December 31, 1976 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) Process Heat and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (impure Helium), 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 progress to date on alloy selection for VHTR Nuclear Process Heat (NPH) applications and for DCHT applications. The present status on the simulated reactor helium loop design and on designs for the testing and analysis facilities and equipment is discussed.

  19. Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, July 1, 1979-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-03-07

    The results of work performed from July 1, 1979 through September 30, 1979 on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. 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. 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 status of the data management system is presented. In addition, the progress in the screening test program is described.

  20. Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, April 1, 1979-June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-25

    The 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. 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 status of the data management system is presented. In addition, the progress in the screening test program is described.

  1. 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。

  2. Characterization of Structural Defects in Wide Band-Gap Compound Materials for Semiconductor and Opto-Electronic Applications

    Science.gov (United States)

    Goue, Ouloide Yannick

    Single crystals of binary and ternary compounds are touted to replace silicon for specialized applications in the semiconductor industry. However, the relative high density of structural defects in those crystals has hampered the performance of devices built on them. In order to enhance the performance of those devices, structurally perfect single crystals must be grown. The aim of this thesis is to investigate the interplay between crystal growth process and crystal quality as well as structural defect types and transport property. To this end, the thesis is divided into two parts. The first part provides a general review of the theory of crystal growth (chapter I), an introduction to the materials being investigated (chapter II and III) and the characterization techniques being used (chapter IV). • In chapter I, a brief description of the theory of crystal growth is provided with an eye towards the driving force behind crystal nucleation and growth along with the kinetic factors affecting crystal growth. The case of crystal growth of silicon carbide (SiC) by physical vapor transport (PVT) and chemical vapor deposition (CVD) is discussed. The Bridgman, travelling heater method (THM) and physical transport growth of cadmium zinc telluride (CZT) is also treated. In chapters II and III, we introduce the compound materials being investigated in this study. While a description of their crystal structure and properties is provided, the issues associated with their growth are discussed. In chapter IV, a description of the characterization techniques used in these studies is presented. These techniques are synchrotron X-ray topography (SXRT), transmission electron microscopy, transmission infrared microscopy (TIM), micro-Raman spectroscopy (muRS) and light microscopy. Extensive treatment of SXRT technique is also provided. In the second part, the experimental results obtained in the course of these studies are presented and discussed. These results are divided into

  3. 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

  4. Mechanical properties test data for structural materials. Quarterly progress report for period ending October 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Hill, M R [comp.

    1976-12-01

    Test data on heat resisting reactor materials are presented. These data were obtained in research at EG and G Idaho, Argonne National Laboratory, Oak Ridge National Laboratory, Naval Research Laboratory, Hanford Engineering Development Laboratory, Westinghouse Advanced Reactors Division, General Electric Company, University of Cincinnati, and University of California at Los Angeles. (JRD)

  5. 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.

  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. 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.

  8. 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.

  9. Science Results from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR): Progress Report

    Science.gov (United States)

    Evans, Diane L. (Editor); Plaut, Jeffrey (Editor)

    1996-01-01

    The Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is the most advanced imaging radar system to fly in Earth orbit. Carried in the cargo bay of the Space Shuttle Endeavour in April and October of 1994, SIR-C/X-SAR simultaneously recorded SAR data at three wavelengths (L-, C-, and X-bands; 23.5, 5.8, and 3.1 cm, respectively). The SIR-C/X-SAR Science Team consists of 53 investigator teams from more than a dozen countries. Science investigations were undertaken in the fields of ecology, hydrology, ecology, and oceanography. This report contains 44 investigator team reports and several additional reports from coinvestigators and other researchers.

  10. [Progress in the application of laser ablation ICP-MS to surface microanalysis in material science].

    Science.gov (United States)

    Zhang, Yong; Jia, Yun-hai; Chen, Ji-wen; Shen, Xue-jing; Liu, Ying; Zhao, Leiz; Li, Dong-ling; Hang, Peng-cheng; Zhao, Zhen; Fan, Wan-lun; Wang, Hai-zhou

    2014-08-01

    In the present paper, apparatus and theory of surface analysis is introduced, and the progress in the application of laser ablation ICP-MS to microanalysis in ferrous, nonferrous and semiconductor field is reviewed in detail. Compared with traditional surface analytical tools, such as SEM/EDS (scanning electron microscopy/energy dispersive spectrum), EPMA (electron probe microanalysis analysis), AES (auger energy spectrum), etc. the advantage is little or no sample preparation, adjustable spatial resolution according to analytical demand, multi-element analysis and high sensitivity. It is now a powerful complementary method to traditional surface analytical tool. With the development of LA-ICP-MS technology maturing, more and more analytical workers will use this powerful tool in the future, and LA-ICP-MS will be a super star in elemental analysis field just like LIBS (Laser-induced breakdown spectroscopy).

  11. 聚氨酯铺地材料的研究进展%Research progress of polyurethane flooring material

    Institute of Scientific and Technical Information of China (English)

    时锋

    2011-01-01

    对聚氨酯铺地材料的发展做了概括,介绍了聚氨酯铺地材料的结构与特点,综述了国内外聚氨酯铺地材料研究进展.详细论述了MDI型聚氨酯体系的发展现状,并阐述了纳米技术在MDI型聚氨酯铺地材料的应用,对聚氨酯铺地材料的发展作了展望.%This paper generalizes the development of polyurethane flooring material and introduces its structure and characteristics. It reviews the research progress on polyurethane flooring material both in and out of the country. The paper presents the current situation of the development of MDI polyurethane system in detail. It expounds the application of nanometer technology in MDI polyurethane flooring material,and finally,it predicts the prospects on the development of polyurethane flooring material.

  12. Band structure analysis on olivine LiMPO{sub 4} and delithiated MPO{sub 4} (M = Fe, Mn) cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ting-Feng, E-mail: tfyihit@163.com [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China); Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Fang, Zi-Kui [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China); Xie, Ying, E-mail: xieying@hlju.edu.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Zhu, Yan-Rong [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China); Dai, Changsong [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-12-25

    Highlights: • The conductivity of Li{sub x}MPO{sub 4} were discussed relying on first principles technique. • Relationship between structure properties and microscopic bonding was addressed. • A mechanism responsible for the structural instability of MnPO{sub 4} was proposed. - Abstract: Olivine compounds, i.e. Li{sub x}MPO{sub 4} (M = Fe, Mn), are now regarded as the most competitive positive-electrode materials for future applications of large-scale rechargeable lithium batteries. There are significant interests in their electronic structures, because the microscopic information is very important for elucidating the structural stability, electrochemical performance, and electronic conductivity issues of batteries for high-rate applications. The structure stabilities of LiMPO{sub 4} and MPO{sub 4} (M = Fe, Mn) cathode materials are analyzed according to first principles calculations. The result shows that LiMPO{sub 4} (M = Fe, Mn) materials exhibit good structure stability, which is mainly contributed to the extremely strong P-O covalent bonds. Furthermore, the introduction of P ions is also helpful for the chemical potential decrease of the materials. The band structure analysis reveals that the electronic conductance of LiFePO{sub 4}, LiMnPO{sub 4}, and FePO{sub 4} is poor, while MnPO{sub 4} possesses half metallic property. According to the electron distribution, it can be confirmed that Mn-O(II) bonds are weakened after Li{sup +} extractions, which is different from the variation trend of Fe-O(II) bonds. The decrease of Mn-O(II) bond strength is thus favorable for the phase transformation observed in experiments.

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1981-09-01

    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 carbon dioxide absorption materials%CO_2吸收材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    郑修新; 张晓云; 余青霓; 赵蓓

    2012-01-01

    全球变暖已成为当前困扰人类生存和发展的重大障碍,因此,CO2吸收材料的研究成为了当前科学研究的热点。本文介绍了CO2捕获和富集的几种方法,主要包括溶剂吸收法、吸附法,并按照基质的不同将吸附法分为金属氧化物类、纤维类、活性炭类、分子筛类、碳纳米管类、聚合物类。同时介绍了其研究进展,并简述了各自的优缺点。指出氨基修饰的碳纳米管是一种很有潜力的CO2吸收材料。%Global warming has become a big problem to human's survival and development.Thus,researches on CO2 absorption materials have attracted more and more attention.In this paper,several technologies are described for the capture and concentration of carbon dioxide,such as solvent absorption and adsorption.The adsorption technologies can be divided into several categories according to its matrix,including metal oxide,fiber materials,activated carbon materials,molecular sieve materials,carbon nanotubes and polymer materials.The research progress of each technology is discussed,and their advantages and disadvantages are introduced briefly.It indicated that amino modified carbon nanotubes are promising materials for the absorption of carbon dioxide.

  16. 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.

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

    Science.gov (United States)

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

    2012-12-04

    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) increasing the binding affinity of hydrogen molecules to surfaces beyond the usual van der Waals interaction. The recent development of reticular chemistry is summarized as a means for addressing the first issue. Theoretical studies focus mainly on the second issue and can be grouped into three classes according to the underlying interaction mechanism: electrostatic interactions based on alkaline cations, Kubas interactions with open transition metals, and orbital interactions involving Ca and other nontransitional metals. Hierarchical computational methods to enable the theoretical predictions are explained, from ab initio studies to molecular dynamics simulations using force field parameters. We also discuss the actual delivery amount of stored hydrogen, which depends on the charging and discharging conditions. The usefulness and practical significance of the hydrogen spillover mechanism in increasing the storage capacity are presented as well.

  18. Progress in High Power Density SOFC Material Development for Aerospace Applications

    Science.gov (United States)

    Cable, Thomas L.; Sofie, Stephen W.; Setlock, John A.; Misra, Ajay K.

    2004-01-01

    Solid oxide fuel cell (SOFC) systems for aircraft applications require order of magnitude increase in specific power density and long life under aircraft operating conditions. Advanced SOFC materials and fabrication processes are being developed at NASA GRC to increase specific power density and durability of SOFC cell and stack. Initial research efforts for increasing specific power density are directed toward increasing the operating temperature for the SOFC system and reducing the weight of the stack. While significant research is underway to develop anode supported SOFC system operating at temperatures in the range of 650 - 850 C for ground power generation applications, such temperatures may not yield the power densities required for aircraft applications. For electrode-supported cells, SOFC stacks with power densities greater than 1.0 W/sq cm are favorable at temperatures in excess of 900 C. The performance of various commercial and developmental anode supported cells is currently being evaluated in the temperature range of 900 to 1000 C to assess the performance gains and materials reliability. The results from these studies will be presented. Since metal interconnects developed for lower temperature operation are not practical at these high temperatures, advanced perovskite based ceramic interconnects with high electronic conductivity and lower sintering temperatures are being developed. Another option for increasing specific power density of SOFC stacks is to decrease the stack weight. Since the interconnect contributes to a significant portion of the stack weight, considerable weight benefits can be derived by decreasing its thickness. Eliminating the gas channels in the interconnect by engineering the pore structure in both anode and cathode can offer significant reduction in thickness of the ceramic interconnect material. New solid oxide fuel cells are being developed with porous engineered electrode supported structures with a 10 - 20 micron thin

  19. Enforcement actions: Significant actions resolved material licensees. Quarterly progress report, April 1995--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (April-June 1995) 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.

  20. Progress in designing CO2 photocatalyst based on energy band match theory%基于能带匹配理论设计CO2光催化还原催化剂的研究进展

    Institute of Scientific and Technical Information of China (English)

    彭辉; 吴志红; 张建林; 卢静; 吴晨啸; 李培强; 尹洪宗

    2014-01-01

    In the process of photocatalytic reduction of CO2,visible light could be absorbed perfectly by the catalyst with a narrowed band gap,but those absorbed light could not be entirely devoted to photocatalytic reduction of CO2,as photocatalytic reduction performance is directly related to energy band location and band structure changing has an important influence on redox ability. Beginning with the CO2 photocatalytic reduction basic principles,this paper is aimed to introduce the basic reduction process of CO2 by semiconductor photocatalyst,the decisive role of valence band and conduction band;to briefly discuss the existing mismatch problem of valence band and conduction band in the process of photocatalytic reduction of CO2;and also to describe how to improve the CO2 photocatalytic reduction efficiency using energy band match theory,such as crystal growth,composite materials,form“p-n junction” and the First Principles,which provides theoretical references for the selection and design of catalyst for the photocatalytic reduction of CO2.%光催化还原 CO2过程中,能带隙小的材料具备优良的可见光吸收性能,但吸收的可见光并不一定能够有效地被光催化还原作用所利用,这与催化剂能带位置有着直接关系,改变材料的能带结构对调节材料的氧化还原性能有着重要影响。本文从光催化还原 CO2的基本原理出发,介绍了半导体催化剂光催化还原 CO2的基本过程及催化剂价带、导带位置的决定性作用,简述了当今光催化还原 CO2过程中存在的催化剂价带、导带不匹配问题,并从特定晶面生长、材料复合、形成p-n结、第一性原理等方面综述了如何利用能带匹配理论来提高光催化还原CO2效率,为光催化还原CO2的材料的选择和设计提供了理论依据。

  1. Progress in Gamma Ray Measurement Information Barriers for Nuclear Material Transparency Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wolford, J.K.; White, G.K.

    2000-07-03

    Negotiations between technical representatives of the US and the Russian Federation in support of several pending nuclear arms and nuclear material control agreements must take account of the need for assurances against the release of sensitive information. Most of these agreements involve storing nuclear material and in some cases nuclear components from stockpile weapons in specially designed containers. Strategies for monitoring the agreements typically include measuring neutron and gamma radiation from the controlled items to verify declared attributes of plutonium or highly enriched uranium. If accurate enough to be useful, these measurements will contain information about the design of the component being monitored, information considered sensitive by one or both parties to the agreement. Safeguards have evolved to prevent disclosure of this information during inspections. These measures combine hardware, software, and procedural measures to contain the sensitive data, presenting only the results needed for verification. Custom features preserve data security and guard against disclosure in case of failure. This paper summarizes the general problem and discusses currently developing solutions for a high resolution gamma ray detection system. It argues for the simplest possible implementation of several key system components.

  2. 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.

  3. Progress Report 2011: Understanding compound phase transitions in Heusler alloy giant magnetocaloric materials

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Shane

    2011-12-13

    Our goal is to gain insight into the fundamental physics that is responsible for magnetocaloric effects (MCE) and related properties at the atomic level. We are currently conducting a systematic study on the effects of atomic substitutions in Ni2MnGa-based alloys, and also exploring related full- and half-Heusler alloys, for example Ni-Mn-X (X=In, Sn, Sb), that exhibit a wide variety of interesting and potentially useful physical phenomena. It is already known that the magnetocaloric effect in the Heusler alloys is fundamentally connected to other interesting phenomena such as shape-memory properties. And the large magnetic entropy change in Ni2Mn0.75Cu0.25Ga has been attributed to the coupling of the first-order, martensitic transition with the second-order ferromagnetic paramagnetic (FM-PM) transition. Our research to this point has focused on understanding the fundamental physics at the origin of these complex, compound phase transitions, and the novel properties that emerge. We synthesize the materials using a variety of techniques, and explore their material properties through structural, magnetic, transport, and thermo-magnetic measurements.

  4. Process feasibility study in support of silicon material Task I. Quarterly technical progress report (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, K.C.; Miller, J.W. Jr.; Yaws, C.L.

    1977-03-01

    During this reporting period, major effects were expended on process system properties, chemical engineering and economic analyses. Major activities were continued on process system properties of silicon source materials under consideration for solar cell grade silicon production. In property correlation efforts, property data results are presented for heat of vaporization, gas heat capacity, liquid heat capacity, liquid density, surface tension and gas viscosity of silane (SiH/sub 4/) as a function of temperature. Major chemical engineering analysis activities are being devoted to preliminary process design for a silane (SiH/sub 4/) plant that will produce 1000 metric tons/year of solar cell grade silicon. The technology developed by Union Carbide for the production of silane uses hydrogen and metallurgical grade silicon as raw materials. Preliminary process flow diagram and base conditions are reported. Preliminary process design was initiated for the conventional polysilicon process now used in the United States to produce semiconductor grade silicon from TCS (trichlorosilane, SiHCl/sub 3/). Economic analysis activities in Task 3 focused on development of a computer model to aid in estimation of product and plant investment costs for the alternate solar cell grade silicon processes. Application of the computer model to the Battelle process (Zn/SiCl/sub 4/) indicated $10,510,000 fixed capital investment and $9.63/KG of silicon for a 1000 metric ton/yr. plant. Economic analysis activities also centered on developing cost standardization techniques for application to the alternate processes.

  5. 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).

  6. 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...

  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. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, April 1, 1982-June 30, 1982

    Energy Technology Data Exchange (ETDEWEB)

    1982-10-01

    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 analyses 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 controlled-purity helium and air in the intensive screening test program is discussed. The results of metallographic studies of corrosion pins exposed at 750/sup 0/C for 6000 hours in controlled-purity helium (solid solution strengthened alloys, centrifugally cast alloys and an iron-base oxide dispersion strengthened alloy) are presented and discussed. The results of metallographic studies on the same materials after 10,000 hour exposure in controlled-purity helium at 850/sup 0/C are also presented.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 正渗透膜材料的研究进展%Research progress of forward osmosis membrane materials

    Institute of Scientific and Technical Information of China (English)

    马岩红; 丁昀; 杨庆; 李鹏

    2014-01-01

    Forward osmosis (FO) technology has received wide attention because of its low energy consumption,contamination resistance and other advantages,and has achieved rapid development in recent years. This paper introduces the influence factors and concentration polarization during the FO process. Internal concentration polarization is an important factor affecting penetration efficiency of FO technology,and preparation of suitable membrane material is the key technology to improve internal concentration polarization .The development of forward osmosis separation technology at home and abroad is also presented. Different materials and structures of forward osmosis membranes have been prepared successfully after years of hard work and research. The latest research progress of the membrane materials in FO field is presented. Application of many forward osmosis membrane materials is restrained by technical difficulties,which should be resolved in the future to shorten the gap between theory and practice,and achieve innovative results in the practical application of membrane materials.%正渗透技术因其低能耗、耐污染等优势受到国际和国内众多学者的关注,尤其近几年来,取得了迅速发展。本文对正渗透过程中的影响因素以及浓差极化现象作了简要分析,结果表明,内浓差极化是影响正渗透技术效率低下的重要因素,而制备适当的膜材料是有效改善内浓差极化的关键技术。回顾了正渗透分离技术在国内外的发展历程,通过不懈的探索和研发,先后成功制备得到不同材料和结构的正渗透膜。重点讲述膜材料在正渗透领域所取得的最新研究进展,最后指出众多正渗透膜材料由于条件限制难以推广应用,希望在未来的研究过程中突破这项技术难题,缩短科研理论与实际应用之间的差距,在膜材料的实际应用方面取得创新性成果。

  20. 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.

  1. Band Together!

    Science.gov (United States)

    Olson, Cathy Applefeld

    2011-01-01

    After nearly a decade as band director at St. James High School in St. James, Missouri, Derek Limback knows that the key to building a successful program is putting the program itself above everything else. Limback strives to augment not only his students' musical prowess, but also their leadership skills. Key to his philosophy is instilling a…

  2. 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.

  3. 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.

  4. Progress in Industrialization of Biobased Materials%生物基材料产业化进展

    Institute of Scientific and Technical Information of China (English)

    谭天伟; 苏海佳; 杨晶

    2012-01-01

    在全球石油资源供给日趋紧张,环保问题日益突出,对低碳经济发展需求日益迫切的情势下,以可再生资源为基础的生物基材料迅速发展成为必然趋势。综述了目前国内外生物基材料产业化的最新进展,系统介绍和总结了乳酸、1,3-丙二醇、聚乳酸、聚丁二酸丁二醇酯、聚羟基脂肪酸酯、透明质酸、大豆蛋白、聚天冬氨酸、木塑复合材料等几种生物基材料产业化最新结果。对比了美国、日本和欧洲等国家生物基材料产业状况,分析了生物基材料产业化的发展趋势及前景。%The latest progress in industrialization of biobased materials was reviewed. The new results of industrialization of several representative biobased materials such as lactic acid, 1, 3-propanediol, poly ( lactic acid) , poly ( butylene succinate) , poly (hydroxyalkanoate) , hyaluronic acid, Xanthan Gum, polyaspartic acid, and wood-plastic composed ma- terials were systematically introduced and summarized. The industrialization situations in US, Japan and Europe were compared. Furthermore, the possible development trend and future were discussed.

  5. 纳米材料改性水性聚氨酯的研究进展%Research progress of waterborne polyurethane modified with nano materials

    Institute of Scientific and Technical Information of China (English)

    张瑾; 马咏梅; 安招鹏

    2015-01-01

    综述了纳米材料改性水性聚氨酯几种常用方法的特点和研究进展,指出了纳米材料改性水性聚氨酯存在的问题。%Several commonly used methods and recent research progress of the nano materials in modified waterborne polyurethane were reviewed. And the existing questions for waterborne polyurethane modified with the nano materials were pointed out.

  6. Low-temperature thermal energy storage quarterly progress report for period July--September 1976. [Phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, H. W.; Kedi, R. J.

    1977-01-31

    The document is the second in a series of quarterly progress reports covering activities funded at ORNL by the ERDA Division of Energy Storage Systems to develop low-temperature thermal energy storage (TES) technology. These systems will be based on either sensible or latent heat storage at temperatures up to approximately 250/sup 0/C. At ORNL, research efforts were continued to (a) develop a time-dependent analytical model that will describe a TES system charged with a phase-change material, (b) measure thermophysical properties and melt-freeze cyclic behavior of interesting PCM's and (c) determine crystal lattice structures of hydrated salts and their nucleators. A report on TES subsystems for application to solar energy sources was completed and is being reviewed. In the area of program management, subcontracts were signed with Clemson University, Dow Chemical Company, Suntek Research Associates, and The Franklin Institute. Detailed reviews were completed for ten unsolicited proposals related to TES. Industries, research institutions, universities, and other national laboratory participation in the TES program, for which ORNL has management responsibilities, are listed.

  7. Research Progress of Rubber Damping Materials%橡胶阻尼减震材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    郭建华; 曾幸荣; 罗权焜

    2012-01-01

    The damping properties of natural rubber(NR), styrene-butadiene rubber(SBR) , (hal-ogenated) butyl rubber(ⅡR) , (hydrogenated) nitrile rubber(NBR), silicone rubber, ethylene-propyl-ene rubber(EPR), ethylene-vinyl acetate rubber(EVM) and their blends were reviewed. The research progress of the preparation of damping rubber materials with comprehensive performances were summarized through rubber blending, copolymerization, filler modification, small organic molecular hybrid damping, solution coprecipitation and interpenetrating network.%介绍了天然橡胶(NR)、丁苯橡胶(SBR)、(卤化)丁基橡胶(IR)、(氢化)丁腈橡胶(NBR)、硅橡胶、乙丙橡胶(EPR)、乙烯-醋酸乙烯酯橡胶(EVM)及其共混物的阻尼性能,综述了采用橡胶共混、共聚、填料改性、有机小分子杂化阻尼、溶液共沉淀和互穿网络(IPN)等方法,制备了综合性能良好的阻尼橡胶减震材料的研究进展.

  8. 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.

  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. 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)

  11. 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.

  12. 不同半导体材料构成光子晶体在太赫兹波段能态密度特性%State Density Properties of Photonic Crystal Composited by Different Semiconductor Material in Terahertz Band

    Institute of Scientific and Technical Information of China (English)

    邴丕彬; 闫昕

    2012-01-01

    Based on the plane wave expansion method research Ⅳ, Ⅲ-Ⅴ and Ⅱ- Ⅵ semiconductor material composition family 2d triangle photonic crystal lattice terahertz band state density of characteristics, numerical simulation to get Ⅳ family in filling SiC rate f = 0. 8 form 0. 037 THz band gap width, Ⅱ-Ⅵ ZnO family in filling rate f = 0. 73 form 0. 0417 THz band gap width form, the filler rate case Ⅲ-Ⅴ race semiconductor material form 0.027 THz band gap width, more data Ⅱ-Ⅵ race semiconductor material form more wide band gap, the result is too Hertz photonic crystal devices to provide the theoretical basis for development.%基于平面波展开法研究Ⅳ、Ⅲ-Ⅴ和Ⅱ-Ⅵ族半导体材料构成二维三角晶格光子晶体在太赫兹波段的能态密度特性,数值模拟得到Ⅳ族SiC在填充率f=0.8时形成0.037 THz带隙宽度,Ⅱ-Ⅵ族ZnO在填充率f=0.73时形成0.0417 THz带隙宽度,不同填充率情况下Ⅲ-Ⅴ族半导体材料形成0.027 THz带隙宽度,比较数据Ⅱ-Ⅵ族半导体材料形成较宽的带隙,研究结果为太赫兹光子晶体器件的开发提供了理论依据.

  13. 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。

  14. The research progress of Tin-based photocatalytic materials on the degradation of organic pollutants%锡基光催化材料降解有机污染物的研究进展∗

    Institute of Scientific and Technical Information of China (English)

    姚凯利; 李俊; 贾庆明; 陕绍云; 苏红莹; 王亚明

    2016-01-01

    硫化锡、磷化锡光催化材料的能带较窄,能对可见光响应,甚至可以实现近红外吸收。氧化锡材料虽然能带较宽,但是通过掺杂及复合等改性手段,也能拓宽其光响应范围。因此,许多研究者在 Sn 基功能半导体材料,尤其是具有低维结构、纳米级Sn基新型材料的制备及光催化性能方面作了大量的研究工作。系统综述了氧化锡、硫化锡、磷化锡等重要的锡基光催化材料在有机物降解方面的研究进展以及光催化降解机理,并对锡基光催化材料的发展提出一些展望及建议。%Tin sulfide,stannic phosphide are narrow band gap photocatalytic materials,can response to visible light,and even can realize the near-infrared absorption.While the band gap of Tin oxide material is wide,by means of doping and composite modification,also can widen the scope of its light response.Therefore,many re-searchers made a great deal of research work in tin-based function semiconductor materials,especially the prep-aration of low dimensional structure,nanoscale tin-based new materials and the photocatalytic performance. This paper systematically reviewed the research progress of tin oxide,tin sulfide,Stannic phosphide and other important tin-based photocatalytic materials in the degradation of organic pollutants,and their photocatalytic degradation mechanism.And putting forward some prospects and suggestions on the development of the tin-based photocatalytic materials.

  15. 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.

  16. 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.

  17. 橡胶减震材料研究进展%Research Progress of Damping Rubber Material

    Institute of Scientific and Technical Information of China (English)

    高超锋; 扈广法; 范晓东

    2012-01-01

    控制振动、降低噪音,已成为当今社会急需解决的问题。文中对橡胶减震材料最近的研究动态作了概述,内容涉及橡胶阻尼减震机理和阻尼减震性能的影响因素。影响橡胶阻尼性能的最主要因素是橡胶的分子结构,其次为填充体系、硫化体系、增塑体系等。文中介绍了阻尼橡胶的改性方法,包括共混、互穿网络技术和填充填料等方法,并指出减震橡胶材料今后的研究方向。%Controlling vibration and reducing noise is an urgent research target in modern society. The latest research progress for damping rubber materials was reviewed in this article. The contents covered the mechanical damping mechanism of rubbers and the related influence factors of the damping property. The primary factor which affected damping property of rubber was the molecular structure of the rubber matrix. The bulk additives, the vulcanization processes and the plasticization systems were also considered as the secondary elements. The modification techniques of damping rubbers such as blending, interpenetrating polymer network (IPN), loading, etc, were introduced. The developing trend of the damping rubbers was summarized based on recent published papers.

  18. 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.

  19. 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.

  20. 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.

  1. Research Progress of Narrow Band Gap Semiconductor Photocatalytic Materials%窄带隙半导体光催化材料研究进展

    Institute of Scientific and Technical Information of China (English)

    占启安

    2013-01-01

    概述了窄带隙半导体光催化材料的光催化反应机理、新型窄带隙半导体光催化材料的种类以及影响窄带隙半导体光催化材料的光催化活性的因素.介绍了传统半导体光催化材料的掺杂改性方法和一些新型的窄带半导体光催化材料.

  2. 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.

  3. 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。

  4. 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.

  5. 基于光子晶体的远红外与激光兼容伪装材料%Far infrared and laser band compatible camouflage material based on photonic crystals

    Institute of Scientific and Technical Information of China (English)

    高永芳; 时家明; 赵大鹏

    2011-01-01

    现代探测系统由单一工作模式向复合工作模式转变,对伪装材料的光谱特性提出了某些特殊要求.光子晶体是一种新型的人工结构功能材料,基于光子禁带的高反射特性,可以实现红外伪装;基于一维掺杂光子晶体,可以实现远红外与激光兼容伪装.设计了一种基于光子晶体的远红外与激光兼容伪装材料,利用薄膜光学理论的特征矩阵法计算了反射光谱,发现可以在反射光谱中的高反射率波段内形成局部窄带低反射区.结果表明:利用一维掺杂光子晶体可以实现远红外与激光兼容伪装.%As the working mode of modem detecting system is changing from single mode to compound one, the spectral characteristics of camouflage materials are required to meet some special requirements.As a new kind of artificial structure function material, photonic crystals can realize infrared camouflage because of its high-efficiency reflection characteristic of photonic band gap; based on one dimensional doped photonic crystal, it can realize far infrared and laser band compatible camouflage.A kind of far infrared and laser band compatible camouflage material was designed, then the reflectance spectrum was calculated by characteristic matrix method based on thin-film optical theory.It was found that a local narrow band low-reflectivity region could be formed within a high -reflectivity band in reflection spectrum.The result shows that one dimensional doped photonic crystal can achieve far infrared and laser band compatible camouflage.

  6. 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.

  7. 3D打印用高分子材料的研究进展%Research Progress of Polymer Materials for 3D Printing

    Institute of Scientific and Technical Information of China (English)

    郭华清; 徐冬梅

    2016-01-01

    综述了通用塑料、工程塑料、生物塑料和光敏树脂等3D打印用材料的研究进展,分析了3D打印高分子材料面临的发展问题,提出了相应的对策。%The research progresses of 3D printing materials modified by general plastics,engineering plastics,bioplastics and photosensitive plastics were reviewed. The problems of 3D printing polymer material countered were analyzed,and the corresponding countermeasures were put forward accordingly.

  8. 微胶囊壁材在食品工业中的研究进展%Research Progress of Microcapsule Wall-materials in Food Industry Extracts

    Institute of Scientific and Technical Information of China (English)

    张碳; 谭天伟; 凌沛学

    2011-01-01

    文中介绍了用于食品工业中微胶囊壁材的特性,讨论了常用微胶囊壁材在实际应用中存在的优缺点及其表征方法和手段,结合最新研究进展,对碳水化合物类壁材、植物亲水性胶类壁材、蛋白类壁材以及新型壁材的开发研究进行了综述。%The article introduced the characteristics of microcapsule wall materials in food industry. Its detecting method and the advantages and disadvantages of the common wall materials in practical applications are also discussed. Especially, the latest research progress of carbohydrates, natural plant gum, proteins wall materials and novel wall materials were summarized

  9. 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.

  10. 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.

  11. 基于光子晶体的中红外与多波段激光兼容伪装材料%Compatible Mid-infrared and Multi-band Laser Camouflage Material Based on Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    苗雷; 李志刚; 徐延亮

    2015-01-01

    In modern war, the detection and precise guidance systems have been developed from single band to composite band, which put forward higher requirements on camouflage material. Photonic crystal as a kind of artifi⁃cial crystal function material, its band gap characteristics are used to realize camouflage at mid-infrared band. The photonic crystal is designed and fabricated by applying electron beam evaporation and thin film deposition technolo⁃gy, which is stealth at 3~5μm and compatible with laser waveband at 0.93μm, 1.06μm and 10.6μm. It is very im⁃portant for aircraft nozzle position stealth. Spectrum analysis shows that the specifications meet application require⁃ments.%针对现代战争探测和精确制导系统由单一波段向复合波段扩展,对伪装材料提出了更高的要求。光子晶体作为一种人工晶体功能材料,利用其带隙特性实现在中红外波段的伪装,采用电子束蒸发和薄膜沉积等技术,设计并制备在3~5μm隐身同时兼容0.93μm,1.06μm和10.6μm激光波段的光子晶体。对飞行器尾喷管部位的隐身具有重要的意义。光谱分析表明,各项指标满足使用要求。

  12. 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.

  13. The role of engineered materials in superconducting tunnel junction X-ray detectors - Suppression of quasiparticle recombination losses via a phononic band gap

    Science.gov (United States)

    Rippert, Edward D.; Ketterson, John B.; Chen, Jun; Song, Shenian; Lomatch, Susanne; Maglic, Stevan R.; Thomas, Christopher; Cheida, M. A.; Ulmer, Melville P.

    1992-01-01

    An engineered structure is proposed that can alleviate quasi-particle recombination losses via the existence of a phononic band gap that overlaps the 2-Delta energy of phonons produced during recombination of quasi-particles. Attention is given to a 1D Kronig-Penny model for phonons normally incident to the layers of a multilayered superconducting tunnel junction as an idealized example. A device with a high density of Bragg resonances is identified as desirable; both Nb/Si and NbN/SiN superlattices have been produced, with the latter having generally superior performance.

  14. 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.

  15. 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.

  16. 脉冲激光沉积制备碳纳米材料进展%PROGRESS IN PREPARATION OF CARBON NANO- MATERIALS BY PULSED LASER DEPOSITION

    Institute of Scientific and Technical Information of China (English)

    姜守振

    2011-01-01

    碳纳米结构的材料由于其优异的性能,已经成为当今材料科学的热点之一,而脉冲激光沉积法由于其独特的优点而越来越受到重视.作者阐述了用脉冲激光沉积法制备各种碳纳米结构的研究进展,包括类金刚石薄膜、碳纳米管和石墨烯.%Carbon nano - size materials are one of the focuses in R&D of new materials due to their excellent performance, and the PLD (pulsed laser deposition) attracts people'a attention more and more because of its unique advantages. The progress in various carbon nano -size materials prepared by PLD is reviewed including diamondlike carbon, carbon nanotube and graphene.

  17. 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.

  18. 有机硅材料辐射加工技术进展%Progress on Radiation Processing Technology of Silicone Materials

    Institute of Scientific and Technical Information of China (English)

    周成飞

    2014-01-01

    The research progress of radiation modification on the silicone materials was summarized .The radiation crosslinking and radiation grafting technique in application of silicone materials were discussed .The current research trend on preparation of POSS-polymer composites was also introduced .Finally, the develop-ment of preparation of SiC materials by radiation technology was introduced .%综述了有机硅材料辐射改性的研究进展。主要评述了辐射交联和辐射接枝技术在有机硅材料改性中的应用情况;介绍了辐射法制备POSS-聚合物复合材料的研究及SiC材料辐射制备技术的发展现状。

  19. Research progress in the sodium-ion battery cathode material%钠离子电池正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    徐硕炯; 张俊喜; 张世明

    2013-01-01

    Some main types of positive materials,including transition metal oxides,poly-anionic compounds for sodium-ion batterieswere discussed.Research progress in the sodium-ion battery cathode material was summarized through the thread of relation between structure and electrochemical performance of all kinds of cathode materials.%介绍了钠离子电池正极材料的几种主要类型,如过渡金属氧化物、聚阴离子化合物的研究进展.以各种正极材料的结构与电化学性能之间的关联为线索,综述了钠离子电池正极材料方面的研究进展.

  20. 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.

  1. 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。

  2. 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...

  3. 酶固定化无机载体材料的研究进展%Research Progress of Inorganic Materials Used as Enzyme Immobilization Carrier

    Institute of Scientific and Technical Information of China (English)

    闵丹丹; 何文; 杜晓永; 张学广; 李彦鹏

    2011-01-01

    In recent years, enzyme immobilization technology has been widely used in food industry, pharmaceuticals, fine chemicals industry, especially chiral compounds,and it has also made some progress in wastewater treatment. However, the physical and chemical properties of the carrier materials directly affect the catalytic activity of the immobilized enzyme. This article describes the commonly used inorganic carrier materials for enzyme immobilization such as traditional inorganic carrier material, modified carrier material and composite inorganic carrier materials, and it also describes the development prospect of enzyme immobilization with the inorganic carrier material.%近年来,酶固定化技术已在食品工业、医药、精细化学品工业,尤其是手性化合物等行业得到广泛应用,在废水处理方面也取得了一定进展。然而,载体材料的物理和化学性能直接影响固定化酶的催化活性。本文介绍了酶固定化常用无机载体材料一传统的无机载体材料、改性无机载体材料以及复合载体材料,并对酶固定化用无机载体材料的发展进行了展望。

  4. 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

  5. Photonic Band Structures of BCC Crystals Containing Dispersive Material%由色散材料构成的体心立方晶体的光子能带计算

    Institute of Scientific and Technical Information of China (English)

    李江蛟

    2004-01-01

    计算了小球排列构成的体心立方结构的光子带隙性质,小球的介电函数可以是极化激元型或等离子型.虽然在通常的介电材料体心立方结构中并不容易形成光子带隙,但在我们考虑的这两类情况中均发现绝对带隙.本文中讨论的光子能带结构是由非常有效的矢量波多重散射方法计算,该方法可以精确地处理介电函数在界面附近的突变.%The photonic band gap properties of an array of spheres arranged in the body-center-cubic (BCC) structure have been calculated. The spheres are made up of dielectric material that has dielectric properties describable by the polariton and plasmon-type dispersion relationship. We find that absolute photonic gaps can be obtained in both cases although the BCC structure is known to be unfavorable for the formation of photonic band gaps. The photonic band structures are calculated by an efficient vector-wave multiple scattering method which can deal accurately with the sharp changes of dielectric functions near the interface.

  6. 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.

  7. 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

  8. 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.

  9. Development and application of photosensitive device systems to studies of biological and organic materials. Progress report, January 1, 1993--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Gruner, S.M.; Reynolds, G.T.

    1993-09-14

    This progress report summarizes results, as of August, 1993, for DOE grant DE-FG-02-76ER60522 during the fiscal period 1/1/93 to 12/31/93, which is the first year of a 3-year grant cycle. The overall goals of the grant are to develop advanced x-ray detector technologies, especially as applicable for biological and materials research at the national laboratories, and to train graduate and post-doctoral students on the use of these technologies via the performance of original biological and materials research. As summarized below, there has been good progress toward achieving the research goals of the original 3-year proposal; in consequence, the research plan and the total budget for the rest of 1993 and beyond is still well described by the original proposal. Accomplishments since the last progress report include: (A) A 1k x 1k fiber optically coupled CCD detector was assembled, tested at CHESS and is slated for extended user trials this Fall. A 2k x 2k CCD detector is being assembled for permanent installation at CHESS. (B) X-ray detector phosphors, calibration techniques, and system software have been developed. (C) The design of a Pixel Array Detector, a collaborative project with the Advanced Photon Source, has been initiated. (D) The properties of biomembrane lipids under extremes of pressure have been investigated. High pressure instrumentation and techniques have been developed. (E) The physics of mesophase formation in biomembrane lipid, surfactant, and polymeric systems have been studied. This includes study of the interaction of membrane proteins with elastically strained lipid bilayers. (G) Work has been initiated on the use of thermal diffuse scatter from proteins as a probe of protein dynamics. (H) Studies on luminescent phenomena have been reported. Since the last progress report (dated 15 May 1992), this work has resulted in 10 published papers, 7 abstracts, 1 Ph.D. thesis and 1 technical report.

  10. 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.

  11. 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.

  12. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, January 1, 1978--March 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-26

    The activities associated with the procurement of the materials for the screening test program, information from vendor certification for the materials received, and preliminary information from the materials characterization tests performed by GE are reported. The construction status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment are discussed. The final recommended impurity levels for the screening phase helium are presented and the rational behind this gas chemistry is discussed. The status of the data management system is presented.

  13. HYBASE : HYperspectral BAnd SElection

    NARCIS (Netherlands)

    Schwering, P.B.W.; Bekman, H.H.P.T.; Seijen, H.H. van

    2009-01-01

    Band selection is essential in the design of multispectral sensor systems. This paper describes the TNO hyperspectral band selection tool HYBASE. It calculates the optimum band positions given the number of bands and the width of the spectral bands. HYBASE is used to assess the minimum number of spe

  14. R&D of Novel Materials for Animal Litters Using High Carbon Fly Ash Final Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett J. [Ceramatec, Inc., Salt Lake City, UT (United States); Kadota, Rod [Ceramatec, Inc., Salt Lake City, UT (United States)

    2012-10-29

    This research program performed by Ceramatec may significantly increase the beneficial utilization of fly ash, and improve the overall performance of high quality animal litter products. Ceramatec has developed a novel high surface area material, which is capable of ammonia adsorption. High surface area zeolites when combined with agglomerated fly ash can significantly reduce the use of naturally mined materials (i.e. clay bentonite) for animal litter manufacture. This not only preserves natural resources and the natural environment, but it also will reduce CO2 emissions, via the reduced need for heavy mining equipment. This novel animal litter is made with over 85% of recycled materials, thus preventing their disposition to landfills. The novel litter material is similar to traditional clay-like litters, and it is clumpable and has superior odor control properties.

  15. 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.

  16. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, April 1--June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-31

    The objectives of the program are to evaluate candidate alloys for Very High Temperature Reactor Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect 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 the report includes the activities associated with the procurement of the materials for the screening test program, information from vendor certification for the materials receiver, and preliminary information from the materials characterization tests performed by General Electric. The construction status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment are discussed. The status of the data management system is also reviewed.

  17. 核壳吸波材料的研究进展∗%Progress in core-shell absorbing materials

    Institute of Scientific and Technical Information of China (English)

    俞梁; 王建江; 许宝才; 李志广; 蔡旭东

    2015-01-01

    As a new core-shell composite absorbing material,as compared with a single type of absorbing mate-rial in the structure,properties and applications of absorbing has obvious advantages,the paper summarizes the basic types of core-shell absorbing materials,preparation methods and proposed a new method for self-reactive quenching + surface modification method.Pointed out that the core-shell absorbing material absorbing material is expected to meet the new"thin,light,wide,strong"requirements,and core-shell absorbing materials re-search proposed future prospects.%核壳吸波材料作为一种新型复合吸波材料,与单一类型的吸波材料相比在结构、吸波性能和应用上有着明显优势,本文总结了核壳吸波材料的基本类型、制备方法及提出了一种新的制备方法-自反应淬熄+表面改性法。指出核壳吸波材料有望满足新型吸波材料“薄、轻、宽、强”的要求,并对今后核壳吸波材料的研究提出展望。

  18. 点击化学反应在聚氨酯材料中的研究进展%The Research Progress of Click Chemical in Polyurethane Material

    Institute of Scientific and Technical Information of China (English)

    李汾

    2016-01-01

    Main types of click chemistry were reviewed. The research progress of click chemical in polyure⁃thane material was emphatically introduced. The current limitation and future application development were ana⁃lyzed.%综述了点击化学反应的主要类型,重点介绍了点击化学在聚氨酯材料中的研究进展,分析了其目前的局限性和今后的应用发展。

  19. Research Progress on Nano-material modified Waterborne Polyurethane%纳米粉体材料改性水性聚氨酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    赵凤艳; 杨大伟; 王全杰

    2011-01-01

    The present applications of nano powder materials in waterborne polyurethane were reviewed. The classification, characteristics and definition of nanometer materials were also discussed, besides the synthesis mechanism and methods of waterborne polyurethane compounding with nano powder materials. It emphasized the progress of nanometer materials in modifying water-borne polyurethane. At last the prospects of the application of nanometer materials in waterborne polyurethane were put forward.%综述了纳米粉体材料在水性聚氨酯中的应用现状,针对纳米材料的分类、特点和定义进行了阐述,以及与水性聚氨酯的作用机理和合成方法。着重介绍了纳米材料在改性水性聚氨酯中的研究进展,并对纳米材料在水性聚氨酯中的应用前景提出展望。

  20. 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.

  1. 磷石膏复合材料的研究进展%Research Progress of Phosphogypsum Composite Materials

    Institute of Scientific and Technical Information of China (English)

    何玉鑫; 万建东; 唐永波; 瞿县; 杨银银; 华苏东; 刘丽娟

    2013-01-01

    磷石膏复合材料是一种新型的绿色环保材料,可大掺量地利用磷石膏直接生产多规格、多品种、强度高、耐水性能好、生产成本低的新型材.讨论了各种磷石膏组分胶凝材料的综合性能、用途以及成型方式.分析了磷石膏复合材料在新型墙体材料中应用的可行性.%The phosphogypsum composite materials which were a new environmentally friendly materials made use of phosphogypsum produced more specifications,multi-species,high strength,water-resistance,low cost.The comprehensive performance,application and molding methods for all kinds of phosphogypsum cementitious materials are discussed,and the feasibility of applying phosphogypsum composite materials in new wall material is analyzed.

  2. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, July 1--September 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-24

    Results of work performed from July 1, 1978 through September 30, 1978 on the Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. Candidate alloys were evaluated for Very High Temperature Reactor Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (Helium containing small amounts of various other gases), the high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. The activities associated with the characterization of the materials for the screening test program are reported, i.e., test specimen preparation, information from the materials characterization tests performed by General Electric, and the status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment. The status of the data management system is presented.

  3. 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)

  4. Evolutions of Compaction Bands of Saturated Soils

    Institute of Scientific and Technical Information of China (English)

    鲁晓兵; 王义华; 崔鹏

    2004-01-01

    The development of compaction bands in saturated soils, which is coupling-rate, inertial and pore-pressure-dependent, under axisymmetric loading was discussed, using a simple model and a matching technique at the moving boundary of a band. It is shown that the development of compaction bands is dominated by the coupling-rate and pore-pressure effects of material. The soil strength makes the band shrinking, whilst pore pressure diffusion makes the band expand. Numerical simulations were carried out in this paper.

  5. 甲烷存储材料的研究进展%The Progress in Methane Storage Materials

    Institute of Scientific and Technical Information of China (English)

    谢会芳; 刘延纯; 冯宝民; 楚文玲

    2014-01-01

    Nature gas (the main component of methane) is considered as a promising alternative fuel due to its abundant reserves, low price and good environmental protection effect. Methane storage is a key technology of natural gas as a vehicle energy application. In this article, three types of representative potential methane storage materials, such as zeolite, porous carbon materials and metal-organic compounds, were reviewed. In particular, the structure and methane storage capability of these materials were systematically discussed. Finally, the insight into the future research on methane storage materials was given.%天然气(主要成分甲烷)以其丰富的储量、低廉的价格以及良好的环保效应成为未来最具发展潜力的清洁能源。甲烷的存储是天然气作为车载能源应用的关键技术之一。本文分别介绍了几类存储甲烷材料,包括分子筛、多孔碳材料、金属-有机骨架化合物的功能特点以及近年来储甲烷材料的研究进展,并指出了储甲烷材料的发展方向。

  6. 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.

  7. 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.

  8. Atomic-Monolayer MoS2 Band-to-Band Tunneling Field-Effect Transistor

    KAUST Repository

    Lan, Yann Wen

    2016-09-05

    The experimental observation of band-to-band tunneling in novel tunneling field-effect transistors utilizing a monolayer of MoS2 as the conducting channel is demonstrated. Our results indicate that the strong gate-coupling efficiency enabled by two-dimensional materials, such as monolayer MoS2, results in the direct manifestation of a band-to-band tunneling current and an ambipolar transport.

  9. Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12).

    Science.gov (United States)

    Li, Ji-Guang; Sakka, Yoshio

    2015-02-01

    This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd(3+) to the activator. Ce(3+) doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Wide band negative magnetic permeability materials (NMPM) with composite metalsemiconductor structures based on the Drude model, and applications to negative-refractive index (NIM).

    Science.gov (United States)

    Benedetti, A; Sibilia, C; Bertolotti, M

    2007-05-28

    Composite structures based on metal open rings and thin wires are well established, for obtaining efficient negative index materials (NIM), acting as metamaterials in the long wavelength regime. The main losses are due both to metal absorption and to the inner electric resistance of metals; to overcome this latter loss we propose a new metal-semiconductor structure dimensioned by direct synthesis method, which offers an almost perfect Drude-like effective magnetic permeability. The choice of particular semiconductor components allows to get a negative resistance for the current induced by the electromagnetic field, which cancels that of the metal but puts a limit to the spectral response of the metamaterial. We consider some parasite effects, such as bianisotropy and incorrect values of structural parameters, to see limitations and features of this new NIM technology.

  16. Comparison of the performance of a few packing materials designed to minimize the thermodynamic band tailing of basic compounds in reversed-phase liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

    2008-01-01

    The adsorption isotherms of phenol, caffeine, propranolol chloride, and amitriptyline chloride were measured on three new brands of C{sub 18}-bonded silica that have been designed to be more resistant than conventional C{sub 18}-bonded silica at high pHs (>8). These columns were the 4 {micro}m Bidendate Cogent-C{sub 18} (Microsolv Technology Corporation, Long Branch, NJ, USA), the 3.5 {micro}m Zorbax Extend-C{sub 18} (Agilent Technologies, Palo Alto, CA, USA), and the 5 {micro}m XTerra-C{sub 18} (Waters, Milford, MA, USA). The originality of these adsorbents is due to their surface chemistry, which protects them from rapid hydrolysis or dissolution at extreme pH conditions. Their adsorption properties were compared to those of the 3 {micro}m Luna-C{sub 18} (Phenomenex, Torrance, CA), which is a more conventional monofunctional material. The adsorption data were acquired by frontal analysis (FA) and the adsorption energy distributions (AEDs) of all systems studied were calculated by the expectation-maximization (EM) method. The experimental results show that neither a simple surface protection (Extend-C{sub 18}) nor the elimination of most of the silanol groups (Cogent-C{sub 18}) is sufficient to avoid a peak tailing of the basic compounds at pH 8 that is of thermodynamic origin. The incorporation of organic moieties in the silica matrix, which was achieved in XTerra-C{sub 18}, the first generation of hybrid methyl/silica material, reduces the silanols activity and is more successful in reducing this peak tailing.

  17. Nanostructured bismuth vanadate-based materials for solar-energy-driven water oxidation: a review on recent progress

    Science.gov (United States)

    Huang, Zhen-Feng; Pan, Lun; Zou, Ji-Jun; Zhang, Xiangwen; Wang, Li

    2014-11-01

    Water oxidation is the key step for both photocatalytic water splitting and CO2 reduction, but its efficiency is very low compared with the photocatalytic reduction of water. Bismuth vanadate (BiVO4) is the most promising photocatalyst for water oxidation and has become a hot topic for current research. However, the efficiency achieved with this material to date is far away from the theoretical solar-to-hydrogen conversion efficiency, mainly due to the poor photo-induced electron transportation and the slow kinetics of oxygen evolution. Fortunately, great breakthroughs have been made in the past five years in both improving the efficiency and understanding the related mechanism. This review is aimed at summarizing the recent experimental and computational breakthroughs in single crystals modified by element doping, facet engineering, and morphology control, as well as macro/mesoporous structure construction, and composites fabricated by homo/hetero-junction construction and co-catalyst loading. We aim to provide guidelines for the rational design and fabrication of highly efficient BiVO4-based materials for water oxidation.

  18. Research Progress in Anode Materials for Power Li-ion Batteries%锂离子动力电池负极材料研究进展

    Institute of Scientific and Technical Information of China (English)

    池永庆; 孙彦平

    2012-01-01

    The progress in research of anode materials of lithium-ion batteries is reviewed. The effects of the compositions, the sizes of the anode materials and the operation temperatures on its performance such as specific capacity, specific power, cycle life and charge/discharge rate capability of the battery, are highlighted, as well as the theoretical studies on the anode materials by mathematical modeling the system of full cell or a half cell of the battery. Improving the performance of the anode materials of carbon/graphite and non-carbon/graphite, preparing the high orderly array anode to enhance the dynamical performance of lithium-ion batteries, will be important aspects for further studying; developing mathematical models to simulate the process of charging and discharging for analyzing the anode dynamics is an efficient way to characterize and optimize the anode materials.%综述了锂离子电池负极材料研究进展,着重介绍了负极材料活性成分、材料尺度及操作温度对电池比容量、比功率、循环寿命、充放电倍率性能的影响,以及数模化半电池或全电池系统对负极材料电极性能的理论研究.为了提高锂离子电池动力性能,改进碳/石墨和非碳/石墨负极材料、制备高度有序的阵列负极将成为今后研究的重要方向;建立数学模型模拟充放电过程、分析负极材料的电极动力学特性,是表征、优化负极材料的有效方法.

  19. 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.

  20. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  1. 多糖类生物降解材料的研究进展%The Research Progress in Polysaccharide-based Biodegradable Materials

    Institute of Scientific and Technical Information of China (English)

    刘泽华; 于九皋

    2000-01-01

      本文详细综述了淀粉基可完全生物降解材料的研究进展,包括淀粉的物理改性(共混)和化学改性(接枝、酯化和交联),并简要介绍了纤维素、壳聚糖等其他多糖类生物降解材料的进展情况。最后提出了改善淀粉类生物降解材料性能的几点设想。%  In this paper, the research progress in starch-based completely biodegradable materials is described in detail, including physical modification (blending) and chemical modifications (grafting, esterification and cross-linking); the other polysaccharide-based biodegradable materials such as cellulose, chitosan and their derivates are also introduced briefly. At last, several suggestions for improving the properties of starch-based biodegradable materials are proposed.

  2. Research Progress on Structural Design of Polymer Matrix Microwave Absorbing Materials%聚合物基吸波材料结构设计研究进展

    Institute of Scientific and Technical Information of China (English)

    段磊; 温变英

    2014-01-01

    The distribution characteristics and types of present absorbents in polymer matrix were introduced. Comparing with the structure of single layer polymer matrix microwave absorbing materials,the design principle of pyramidal, double layer and multi layer of polymer matrix microwave absorbing materials was emphasized. The structure feature and research progress on pyramidal and layer structure of polymer matrix microwave absorbing materials were reviewed, and future development trends was also presented.%介绍了目前吸收剂在聚合物基体中的分布特点和类型,通过与单层聚合物基吸波材料的结构对比,重点阐述了聚合物基吸波材料角锥、双层、多层结构的设计原理。同时对聚合物基吸波材料的角锥和层状结构特征与研究进展进行了综述,并对其发展方向提出了展望。

  3. 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。

  4. 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.

  5. 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.

  6. 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.

  7. K-Band Latching Switches

    Science.gov (United States)

    Piotrowski, W. S.; Raue, J. E.

    1984-01-01

    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  8. K-band latching switches

    Science.gov (United States)

    Piotrowski, W. S.; Raue, J. E.

    1984-05-01

    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  9. 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.

  10. Progress in Research on Cathode Materials of Lithium Ion Batteries%锂离子电池正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    麦立强; 邹正光; 陈寒元

    2000-01-01

    Progress in research on the cathode materialsLi-Co-O、Li-Ni-O、Li-Mn-O spinels and the Li-V-O、Li-Ti-O spinels is reviewed,especially the synthesis methods and their influence on properties. Relevant literature has heen compared,and the problems still facing the area have also been discussed.%综述了锂离子电池正极材料Li-Co-O、Li-Ni-O、Li-Mn-O体系及Li-V-O、Li-Ti-O等体系的研究进展,重点介绍了合成方法及其对性能的影响,并对有关文献进行了比较归纳,指出研究中存在的问题。

  11. 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

  12. Process feasibility study in support of silicon material, Task I. Quarterly technical progress report (XVIII), December 1, 1979-February 29, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Yaws, C.L.; Li, K.Y.

    1980-03-01

    Analyses of process system properties were continued for important chemical materials involved in the several processes under consideration for semiconductor and solar cell grade silicon production. Major activities were devoted to physical, thermodynamic and transport property data for silicon. Property data are reported for vapor pressure heat of vaporization, heat of sublimation, liquid heat capacity and solid heat capacity as a function of temperature to permit rapid usage in engineering. Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for production of silicon was initiated. The process is based on hydrogen reduction of dichlorosilane (DCS) to produce the polysilicon. The chemical vapor deposition reaction for DCS is faster in rate than the conventional process route which utilizes trichlorosilane (TCS) as the silicon raw material. Status and progress are reported for primary activities of base case conditions (30%), reaction chemistry (25%) and process flow diagram (20%). Discussions with HSC and construction of a process flow diagram are in progress. Preliminary economic analysis of the BCL process (case B) was completed. Cost analysis results are presented based on a preliminary process design of a plant to produce 1000 metric tons/year of silicon. Fixed capital investment for the plant is $14.35 million (1980 dollars) and product cost without profit is 11.08 $/kg of silicon (1980 dollars). Cost sensitivity analysis indicate that the product cost is influenced most by plant investment and least by labor. For profitability, a sales price of 14 $/kg (1980 dollars) gives a 14% DCF rate of return on investment after taxes.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 硅基聚合物陶瓷前驱体作为连接剂的研究进展%Research Progress in Silicon-Based Preceramic Polymers for Joining Materials

    Institute of Scientific and Technical Information of China (English)

    刘伟; 罗永明; 徐彩虹

    2011-01-01

    概述了近年来硅基聚合物陶瓷前驱体作为连接剂的研究进展,并对影响其连接强度的因素进行了总结.%Polymer preceramics have become an important joining material for graphite, ceramic and their composite materials. The research progress in silicon-based preceramic polymers for joining materials was reviewed, and the factors affecting the joining strength were summarized.

  19. Research Progress of Electromagnetic Shielding Material of Metal Fiber%金属纤维电磁屏蔽材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    王建忠; 奚正平; 汤慧萍; 黄卫东; 朱纪磊; 李程; 敖庆波

    2011-01-01

    The present paper describes briefly the harm of electromagnetic radiation and the mechanism of electromagnetic shielding material and it focuses on the application and research progress of electromagnetic shielding fabric, electromagnetic shielding polymer and electromagnetic shielding architecture and decoration material made by metal fiber and predicts the development of electromagnetic shielding material in the future. It points out that great attention should be paid to developing an advanced, high-property, low-consumption and green-environment-protection electromagnetic shielding materials with high absorption and low reflection and transmission. Furthermore, it considers that the internal composition and structure need optimizing and the forming process needs improving in order to enhance shielding effectiveness.%描述电磁辐射的危害及电磁屏蔽材料的屏蔽机制,重点阐述金属纤维制备电磁屏蔽织物、电磁屏蔽聚合物材料及电磁屏蔽建筑与装饰材料的应用及研究进展,并对未来电磁屏蔽材料的发展趋势作预测,指出开发具有高吸收率、低反射率与低透射率的高性能、低消耗兼绿色环保的新型电磁屏蔽材料是未来的研究重点,同时对材料内部组织与结构进行优化,改进成型工艺,提高其电磁屏蔽效能.

  20. Progress and Trends in Polymer Damping Materials%高分子阻尼材料研究进展及发展趋势

    Institute of Scientific and Technical Information of China (English)

    黄微波; 刘超; 黄舰

    2012-01-01

    Polymer damping materials is becoming increasingly applied to the automobiles, ships, aerospace and other fields. The latest progress research in domestic and foreign of polymer damping materials is reviewed, the damping mechanism and influencing factors of reducing vibration and noise are expounded. At last, the engineering application and development prospect are introduced. The results show that choose the right resin, functional fillers and modification methods, the high-damping materials for a wide temperature range can be obtained. Polymer damping materials develops constantly toward high damping, wide temperature range, environmental friendly and possessing other excellent comprehensive performances and the application is prosperous.%高分子阻尼材料以其优异的减振降噪性能在汽车、船舶、航空航天等诸多领域得到了越来越多的应用.重点综述了国内外高分子阻尼材料的最新研究进展,详细阐述了其减振降噪的作用机理,深入分析了影响其减振降噪的相关因素,并概括地介绍了其工程应用情况和发展前景.研究表明,通过选择合适的树脂基料、功能填料及改性方法,可制得高性能、宽温域的阻尼材料,以达到减振降噪的目的.高分子阻尼材料正不断朝着具有高阻尼、宽温域、环境友好等具有多项优异综合性能的方向发展,应用前景广阔.

  1. 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.

  2. 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.

  3. 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...

  4. Low Power Band to Band Tunnel Transistors

    Science.gov (United States)

    2010-12-15

    the E-field and tunneling at the source- pocket junction you form a parasitic NPN + transistor and the injection mechanism of carriers into the...hypothesis that the 1000 ° C, 5s anneal split lead to a very wide pocket and the accidental formation of a NPN + transistor , while the 1000 ° C, 1s anneal...Low Power Band to Band Tunnel Transistors Anupama Bowonder Electrical Engineering and Computer Sciences University of California at Berkeley

  5. 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。

  6. Recent Progress in Sodium-ion Battery Materials%钠离子电池关键材料研究进展

    Institute of Scientific and Technical Information of China (English)

    沈晓辉; 卲乐; 田占元

    2016-01-01

    钠离子电池作为一种电化学能量储存与转换装置,具有原料来源丰富和成本低的优势,近年来吸引了国内外研究者的广泛关注。钠离子电池关键材料和相关技术近几年发展迅速,取得了重要进展,研究体系不断丰富。文章对钠离子电池正极材料和负极材料最新研究进展进行了综述,探讨了电极材料目前所面临的主要问题及可能的解决方案,分析了钠离子电池未来的研究发展方向。%Sodium ion batteries (SIBs) receive signiifcant attention for electrochemical energy storage and conversion owing to the large abundance of sodium resources and its low cost. In recent years, the key materials and related technology of sodium ion batteries have developed rapidly and made signiifcant progress, related components have been enriched. The recent advancements of cathode and anode materials for sodium ion batteries are reviewed in details, which have signiifcant effects on the electrode performance. The main problems of these kinds of electrode materials are discussed and the probable strategies are proposed. Finally, the research directions of sodium ion batteries in the future are also forecasted.

  7. 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

  8. Research Progress of GaInAsN Photovoltaic Material%GaInAsN光伏材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    董琛; 韩修训; 孙文华; 高欣

    2016-01-01

    GaInAsN has attracted much attention because the lattice matching can be achieved between GaIn-AsN and several importemt substrates (GaAs,Ge,etc)and the energy-gap requirement of three or four-junction solar cells can be fulfilled as well.Nevertheless the preparation of high-quality GaInAsN material is still a big challenge at present.It is mainly because the low solid solubility of N in GaInAs can leads to the inhomogeneous incorporation,and the resulting N defects can greatly reduce the photoelectric properties of GaInAsN.In this review,recent research progresses of GaInAsN material used in solar cells are summarized,and the basic physical properties of GaInAsN are introduced.Furthermore,the key issues in the GaInAsN material system are analyzed in detail,and the methods of optimizing the quality of GaInAsN material and the performance of related solar cells are discussed as well.Finally, the developing trends of GaInAsN photovoltaic material are prospected.%GaInAsN能与GaAs、Ge等重要衬底晶格匹配,并同时满足三结或四结太阳能电池的带隙要求,因而备受瞩目。但目前制备高质量的GaInAsN材料仍十分困难,主要原因在于N在GaInAs中的固溶度特别低,难以实现均匀并入,由此产生的N缺陷很大程度上降低了该材料体系的光电性能。总结了近年来GaInAsN薄膜材料应用于太阳能电池的研究进展,介绍了GaInAsN材料体系的研究历程和基本物理特性,分析了GaInAsN材料体系存在的关键问题,讨论了目前优化GaInAsN薄膜质量和太阳能电池性能的方法。在此基础之上,对GaInAsN光伏材料的研究发展趋势做了展望。

  9. 磁驱动相变材料研究进展%Progress of Magnetic Field-Driven Phase Transformation Materials

    Institute of Scientific and Technical Information of China (English)

    聂志华; 王沿东; 刘冬梅

    2012-01-01

    Magnetic field-driven phase transformation material is a class of smart material which combines the functional behaviors of ferroelastic shape memory and magnetostriction. The large magnetic field-induced strain obtained in magnetic field-driven phase transformation materials can be achieved through two mechanisms, which include reorientation of mar- tensitic variants caused by the magnetic field-induced twin boundary motion and shape memory effect via magnetic field-in- duced first order phase transformation. Heusler-type Ni-Mn-X(X = Ga or In) magnetic field-driven phase transformation alloys are potential candidates for magnetic sensors and actuators, owing to their large magnetic field-induced strain, high energy density and rapid response and so on. The research progresses of magnetic field-driven phase transformation materi- als, including Ni-Mn-Ga alloys, Ni-Co-Mn-In alloys and antiferromagnets, are summarized. And recent researches from our group are introduced, which are focused on in-situ studies of magnetic field-driven phase transformation materials using high-energy x-ray diffraction and neutron scattering techniques. At last, future trends of magnetic field-driven phase trans- formation alloy are prospected.%磁驱动相变材料利用外磁控制下铁弹马氏体变体重排或磁诱导一级相变产生的形状记忆效应来捕获应变,兼具铁弹形状记忆与磁致伸缩功效特征。Heusler型Ni—Mn.X(X=Ga或In)系磁驱动相变合金材料具有磁感生应变大、能量密度高、反应速度快等优点,是未来重要磁传感器和磁驱动器研制的关键。主要介绍了国内外Ni-Mn-Ga、Ni-Co-Mn-In、反铁磁体等磁驱动相变材料的研究进展,以及本课题组利用高能Xx射线衍射和中子散射技术对磁驱动相变材料的原位研究。最后,展望了磁驱动相变合金材料的发展趋势。

  10. 面向等离子体钨基材料的增韧研究最新进展%Recent progress on toughening of tungsten-based materials as plasma facing materials

    Institute of Scientific and Technical Information of China (English)

    何培; 姚伟志; 吕建明; 张向东

    2016-01-01

    Pure tungsten and tungsten-based materials are promising candidates as plasma facing materials in fu-sion application due to their high melting point,good thermal conductivity,low vapor pressure,low sputter rates and low radioactivity.However,the intrinsic brittleness is considered as the main restricting factor for tungsten-based materials and draws the maj or focus of the international fusion materials community.This paper reviews recent progress of three main strategies on toughening of tungsten-based materials:alloying,dispersion strengthening and composite.Presently only Rehnium addition is known to improve tungsten fracture properties by alloying.Proper mechanical working/treatment decreases ductile-brittle transition temperature of dispersion strengthened tungsten alloys.The ductile-brittle transition temperature of tungsten foil laminates by brazing is decreased to 150 ℃.%钨及钨基材料由于其高熔点、高热导率、低蒸气压、低溅射产额及低辐照放射性等优异性能,成为具有广阔应用前景的面向等离子体材料.然而,钨基材料的本征脆性成为其作为聚变材料的主要限制因素,也成为国际聚变材料界的研究热点.本文综述了通过合金化、弥散强化以及复合材料等3种途径来增加钨基材料韧性的最新研究进展.目前合金元素中只有铼的添加能够显著改善钨的韧性;单一弥散强化方式难以有效提高钨的韧性,适当的热机械加工能够明显降低钨基材料的韧脆转变温度;通过钨箔钎焊制备出的钨层压结构复合材料的韧脆转变温度降低到了150℃.

  11. The Research Progress of Inducing Source Materials of Oriental Fruit Moth%梨小食心虫诱源物质研究进展

    Institute of Scientific and Technical Information of China (English)

    冉红凡; 刘文旭; 马爱红; 孙海鹏; 李建成; 路子云

    2016-01-01

    The oriental fruit moth was world widely distributed fruit borer, and it was hard to be con-trolled for its boring habits. Integrated pest management (IPM) is the focus of people’s attention, which is in line with the current requirements of environmental protection. In IPM of the oriental fruit moth, trapping was an important part. At present,the main inducing source materials for oriental fruit moth in-cluding sex pheromone,sugar-acetic-acid liquid,plant volatiles and different light source in its trapping control. The research progress and influence factors of inducing source materials were introduced, and its application prospect was analysized in this article.%梨小食心虫是世界性分布的蛀果害虫,具有钻蛀为害习性,因此很难进行有效防治。害虫综合治理符合当前人们对环保的要求,成为关注的焦点。在梨小食心虫综合治理体系中,诱捕诱杀成虫是重要的组成部分。目前在梨小食心虫的诱捕防治中,主要的诱源物质包括性信息素、糖醋液、植物源引诱剂、光源等。介绍了不同诱源物质的研究进展、影响因素等,并对其应用前景进行了分析。

  12. Tulane/Xavier University Hazardous Materials in Aquatic Environments of the Mississippi River Basin. Quarterly progress report, January 1, 1995--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    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.

  13. Research Progress on Waterproof Additive in Phosphogypsum Building Materials%磷石膏建材防水添加剂研究进展

    Institute of Scientific and Technical Information of China (English)

    李兵

    2015-01-01

    磷石膏是硫酸湿法萃取磷酸时排出的固体废弃物,每生产1t湿法磷酸约产生5t磷石膏。如何有效地利用磷石膏,生产建筑材料是人们极力寻求解决的问题,进行磷石膏防水剂的开发利用具有重要意义。本文总结了磷石膏防水剂的研究现状,然后对磷石膏的防水性作用原理进行了详细的介绍,对磷石膏防水添加剂研究进展进行了综述。%Phosphogypsum is discharged when phosphoric acid was extracted by WPA , 5 t phosphogypsum was produced when 1 t wet phosphoric acid was produced.How to effectively use phosphogypsum , product building materials is the problem that people struggle to solve , development and utilization of phosphogypsum waterproofing agent is important.The research status of phosphogypsum waterproofing agent was summarized , the role of the principle of waterproof phosphogypsum was detaily presented , research progress of phosphogypsum waterproof additives was reviewed.

  14. 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.

  15. 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.

  16. Narrow band gap conjugated polymers for emergent optoelectronic technologies

    Science.gov (United States)

    Azoulay, Jason D.; Zhang, Benjamin A.; London, Alexander E.

    2015-09-01

    Conjugated organic molecules effectively produce and harvest visible light and find utility in a variety of emergent optoelectronic technologies. There is currently interest in expanding the scope of these materials to extend functionality into the infrared (IR) spectral regions and endow functionality relevant in emergent technologies. Developing an understanding of the interplay between chemical and electronic structure in these systems will require control of the frontier orbital energetics (separation, position, and alignment), ground state electronic configurations, interchain arrangements, solid-state properties, and many other molecular features with synthetic precision that has yet to be demonstrated. Bridgehead imine substituted 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) structural units, in combination with strong acceptors with progressively delocalized π-systems, afford modular donor-acceptor copolymers with broad and long wavelength absorption that spans technologically relevant wavelength (λ) ranges from 0.7 < λ < 3.2 μm.1 Here we demonstrate that electronic and structural manipulation play a major role in influencing the energetics of these systems and ultimately controlling the band gap of the materials. These results bear implication in the development of very narrow band gap systems where precise control will be necessary for achieving desired properties such as interactions with longer wavelength light.

  17. 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

  18. 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,…

  19. 锰基锂正极半导体材料禁带特性研究%Study on the band gap character of Mn-base lithium anode material

    Institute of Scientific and Technical Information of China (English)

    吴汉杰; 梁兴华; 黄美红; 宋清清; 刘浩

    2015-01-01

    For doping Ni and Fe solid material, studying on Mn-base lithium anode material by using high temperature synthesis method, the preparation of the Mn-Base lithium anode semiconductor material LiNi0.5Mn1.5O4, LiNi0.5Mn1.5Fe0.1O4 and LiNi0.5Mn1.5Fe0.2O4. The crystal structure of the sample was analyzed and collected through X-ray diffractometry (XRD), It also tested spectrum features of the material by using ultraviolet visible spectrophotometer, The character of charge-discharge were showed by high precision electrical tester. Testing results showed that Mn-base lithium anode semiconducting material was diamond structure, crystal structure was space group of Fd3m and the cubic crystal system. When absorption coefficient of ultraviolet visible light of LiNi0.5Mn1.5O4, LiNi0.5Mn1.5Fe0.1O4 and LiNi0.5Mn1.5Fe0.2O4 were respectively 0.830, 0.839 and 0.857, the width of the band gap were respectively 2.24e V, 2.22e V, 1.85eV. Electrical characteristics tests indicated that there were two charge–discharge platforms and between 3.45 V and 4.8 V in the semi-finished products of the battery.%采用高温合成法对掺杂Ni和Fe固体物质锰基锂正极材料进行研究,制备出锰基锂正极半导体材料LiNi0.5Mn1.5O4,LiNi0.5Mn1.5Fe0.1O4和LiNi0.5Mn1.5Fe0.2O4,利用X射线衍射仪分析该产物的晶体结构,运用紫外可见光纤光谱仪测试该材料的光谱特征,采用高精度电池测试仪测试半电池的充放电特性.测试结果表明:锰基锂正极半导体材料为立方尖晶石结构,其晶体结构是立方晶系,Fd3m空间群.LiNi0.5Mn1.5O4,LiNi0.5Mn1.5Fe0.1O4和LiNi0.5Mn1.5Fe0.2O4的紫外可见光吸收系数分别处于0.830,0.839和0.857时,禁带宽度分别为0.989 eV,0.966 eV和0.922 eV.半电池电特性测试表明:充放电电压范围处于3.45 V~4.8 V区间,充放电出现了2个平台.

  20. Band Excitation in Scanning Probe Microscopy: Recognition and Functional Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jesse, Stephen [ORNL; Vasudevan, Dr. Rama [Oak Ridge National Laboratory (ORNL); Collins, Liam [University College, Dublin; Strelcov, Evgheni [ORNL; Okatan, Mahmut B [ORNL; Belianinov, Alex [ORNL; Baddorf, Arthur P [ORNL; Proksch, Roger [Asylum Research, Santa Barbara, CA; Kalinin, Sergei V [ORNL

    2014-01-01

    Field confinement at the junction between a biased scanning probe microscope s (SPM) tip and solid surface enables local probing of various bias-induced transformations such as polarization switching, ionic motion, or electrochemical reactions to name a few. The nanoscale size of the biased region is smaller or comparable to features like grain boundaries and dislocations, potentially allows for the study of kinetics and thermodynamics at the level of a single defect. In contrast to classical statistically averaged approaches, this allows one to link structure to functionality and deterministically decipher associated mesoscopic and atomistic mechanisms. Furthermore, this type of information can serve as a fingerprint of local material functionality, allowing for local recognition imaging. Here, current progress in multidimensional SPM techniques based on band-excitation time and voltage spectroscopies is illustrated, including discussions on data acquisition, dimensionality reduction, and visualization along with future challenges and opportunities for the field.

  1. Complex band structure and superlattice electronic states

    Science.gov (United States)

    Schulman, J. N.; McGill, T. C.

    1981-04-01

    The complex band structures of the bulk materials which constitute the alternating layer (001) semiconductor-semiconductor superlattice are investigated. The complex bands near the center of the Brillouin zone in the [001] direction are studied in detail. The decay lengths of superlattice states whose energies lie in the bulk band gaps of one of the semiconductors are determined from the dispersion curves of these bands for imaginary k-->. This method is applied using a tight-binding band-structure calculation to two superlattices: the AlAs-GaAs superlattice and the CdTe-HgTe superlattice. The decay lengths of AlAs-GaAs superlattice conduction-band minimum states are found to be substantially shorter than those for the CdTe-HgTe superlattice. These differences in the decay of the states in the two superlattices result in differences in the variation of the conduction-band effective masses with the thickness of the AlAs and CdTe layers. The conduction-band effective masses increase more rapidly with AlAs thickness in the AlAs-GaAs superlattice than with CdTe thickness in the CdTe-HgTe superlattice.

  2. Apparatus for producing a thin sample band in a microchannel system

    Science.gov (United States)

    Griffiths, Stewart K.

    2008-05-13

    The present invention improves the performance of microchannel systems for chemical and biological synthesis and analysis by providing a method and apparatus for producing a thin band of a species sample. Thin sample bands improve the resolution of microchannel separation processes, as well as many other processes requiring precise control of sample size and volume. The new method comprises a series of steps in which a species sample is manipulated by controlled transport through a junction formed at the intersection of four or more channels. A sample is first inserted into the end of one of these channels in the vicinity of the junction. Next, this sample is thinned by transport across the junction one or more times. During these thinning steps, flow enters the junction through one of the channels and exists through those remaining, providing a divergent flow field that progressively stretches and thins the band with each traverse of the junction. The thickness of the resulting sample band may be smaller than the channel width. Moreover, the thickness of the band may be varied and controlled by altering the method alone, without modification to the channel or junction geometries. The invention is applicable to both electroosmotic and electrophoretic transport, to combined electrokinetic transport, and to some special cases in which bulk fluid transport is driven by pressure gradients. It is further applicable to channels that are open, filled with a gel or filled with a porous or granular material.

  3. Diffuse Interstellar Bands and Their Families

    CERN Document Server

    Wszolek, B

    2006-01-01

    Diffuse interstellar bands (DIBs) still await an explanation. One expects that some progress in this field will be possible when all the known DIBs are divided into families in such a way that only one carrier is responsible for all bands belonging to the given family. Analysing high resolution optical spectra of reddened stars we try to find out spectroscopic families for two prominent DIBs, at 5780 and 5797 angstroms. Among the DIBs, observed in the spectral range from 5590 to 6830 angstroms, we have found 8 candidates to belong to 5780 spectroscopic family and the other 12 DIBs candidating to family of 5797 structure.

  4. Design investigation of a cost-effective dual-band (MWIR/LWIR) and a wide band optically athermalized application

    Science.gov (United States)

    Ding, Fujian; Washer, Joe; Morgen, Daniel

    2016-10-01

    Dual-band and wide-band lenses covering both the MWIR and LWIR spectral bands are increasingly needed as dualband MWIR/LWIR detectors have become prevalent and broadband applications have expanded. Currently in dual-band /wide-band applications, the use of more than three elements per lens group and the use of chalcogenide glass is common. This results in expensive systems. Also, many chalcogenides are available only in small diameters, which is a problem for large aperture broadband lenses. In this paper an investigation of cost-effective designs for dual-band MWIR/LWIR lens using only widely available IR materials, specifically Ge, ZnSe and ZnS were performed. An athermalized dual-band MWIR/LWIR using these three materials is presented. The performance analysis of this lens shows that this design form with these three common IR materials works well in certain applications. The required large size blanks of these materials can be easily obtained. Traditional chromatic aberration correction without diffraction for either wide-band or dual-band application was employed. In addition, the methods of harmonic diffraction for dual-band applications, especially with one narrow band, were used for two different presented designs.

  5. 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.

  6. Cd-free buffer layer materials on Cu2ZnSn(SxSe1-x)4: Band alignments with ZnO, ZnS, and In2S3

    Science.gov (United States)

    Barkhouse, D. Aaron R.; Haight, Richard; Sakai, Noriyuki; Hiroi, Homare; Sugimoto, Hiroki; Mitzi, David B.

    2012-05-01

    The heterojunctions formed between Cu2ZnSn(SxSe1-x)4 (CZTSSe) and three Cd-free n-type buffers, ZnS, ZnO, and In2S3, were studied using femtosecond ultraviolet photoemission and photovoltage spectroscopy. The electronic properties including the Fermi level location at the interface, band bending in the CZTSSe substrate, and valence and conduction band offsets were determined and correlated with device properties. We also describe a method for determining the band bending in the buffer layer and demonstrate this for the In2S3/CZTSSe system. The chemical bath deposited In2S3 buffer is found to have near optimal conduction band offset (0.15 eV), enabling the demonstration of Cd-free In2S3/CZTSSe solar cells with 7.6% power conversion efficiency.

  7. 自修复聚合物材料的研究进展%Research Progresses in Self-Healing Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    祁恒治; 赵蕴慧; 朱孔营; 袁晓燕

    2011-01-01

    Self-healing was put forward to cope with slight damages in polymer materials which are difficult to detect.Research progress in self-healing polymer materials in recent years is summarized in this paper.According to the healing agents employing or not,self-healing methods in polymer materials or polymer composites can be classified into two categories,namely,extrinsic and intrinsic.The extrinsic self-healing polymer materials accomplish self-healing with the aid of self-healing agents incorporated in microcapsules or hollow-fibers.The self-healing agents are released when microcapsules or hollow-fibers are attacked by microcracks,and then reactions involved self-healing take place and the crack surfaces are bonded together to achieve self-healing.This method performs easily and efficiently,but the self-healing process can not be repeated and the candidates of self-healing agents are limited.On the other hand,the intrinsic self-healing polymers bring into effect with the help of Diels-Alder reactions,dynamic covalent chemistry,disulfide-bond reactions,supramolecular structure with hydrogen-bond,π-π stacking,ionomes and so on.Furthermore,the chemical reactions related to these special molecular structures are reversible.Though the preparation of intrinsic self-healing polymers is more complicated,the self-healing process is efficient in repeatable manner.So,the durability of polymer materials can be extended.This paper reviews mainly on the specialities and applications of the above self-healing methods in polymer materials.%针对聚合物材料在使用过程中难以检测的损伤,人们引入了自修复概念。本文就近年来自修复聚合物材料的研究进展作了系统综述。根据自修复过程是否使用修复剂,聚合物材料(包括聚合物基复合材料)的自修复可分为外援型和本征型两大类。外援型自修复借助于外加修复剂实现自修复,主要包括埋植微胶囊化修复剂和埋植中空纤维化修

  8. Diet after gastric banding

    Science.gov (United States)

    ... helps people who have a gastric band stay satisfied longer. This includes things like salad with grilled ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  9. 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.

  10. HYBASE - HYperspectral BAnd SElection tool

    NARCIS (Netherlands)

    Schwering, P.B.W.; Bekman, H.H.P.T.; Seijen, H.H. van

    2008-01-01

    Band selection is essential in the design of multispectral sensor systems. This paper describes the TNO hyperspectral band selection tool HYBASE. It calculates the optimum band positions given the number of bands and the width of the spectral bands. HYBASE is used to calculate the minimum number of

  11. Bi-directional evolutionary optimization for photonic band gap structures

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fei [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); School of Civil Engineering, Central South University, Changsha 410075 (China); Huang, Xiaodong, E-mail: huang.xiaodong@rmit.edu.au [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); Key Laboratory of Advanced Technology for Vehicle Body Design & Manufacture, Hunan University, Changsha, 410082 (China); Jia, Baohua [Centre for Micro-Photonics, Faculty of Engineering & Industrial Science, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122 (Australia)

    2015-12-01

    Toward an efficient and easy-implement optimization for photonic band gap structures, this paper extends the bi-directional evolutionary structural optimization (BESO) method for maximizing photonic band gaps. Photonic crystals are assumed to be periodically composed of two dielectric materials with the different permittivity. Based on the finite element analysis and sensitivity analysis, BESO starts from a simple initial design without any band gap and gradually re-distributes dielectric materials within the unit cell so that the resulting photonic crystal possesses a maximum band gap between two specified adjacent bands. Numerical examples demonstrated the proposed optimization algorithm can successfully obtain the band gaps from the first to the tenth band for both transverse magnetic and electric polarizations. Some optimized photonic crystals exhibit novel patterns markedly different from traditional designs of photonic crystals.

  12. Research progress of graphene in composite material%石墨烯在复合材料领域的应用研究进展

    Institute of Scientific and Technical Information of China (English)

    张彩丽

    2016-01-01

    综述了近几年石墨烯的研究进展、制备方法并分析比较了各种方法的优缺点。物理法能得到高质量的石墨烯,但不能大规模生产;采用化学沉淀法制备的石墨烯的形貌和性能受基体影响较大,综合制造成本较高;采用化学还原法制备的石墨烯的成本较低,可大规模制备而且适用于制备高分子复合材料,但其分子结构受到破坏且易发生团聚。依托中国企业和院校等研究机构的合成材料研发平台,结合国内丰富的天然石墨资源,提出了石墨烯在复合材料领域的研究方向和应用前景。%This paper provides an overview of the research progress of graphene in recent years along with its preparation processes in terms of relative merits. Among which, physical method can be used to produce high quality graphene in small scale; the morphology and properties of graphene prepared by chemical precipitation are affected by basal body with high production costs; the product made by chemical reduction is competitive in large scale production due to low costs and can be used to prepare high polymer composites, while whose mo-lecular structure is prone to agglomeration. The future research direction and application prospect of graphene in composite material is proposed based on the R&D platform established by Chinese research institutes and abun-dant natural graphite resources in China.

  13. 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.

  14. 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

  15. 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.

  16. Research Progress on Nano Materials applied in Modified Waterborne Polyurethane%纳米材料在改性水性聚氨酯中的研究进展

    Institute of Scientific and Technical Information of China (English)

    曲家乐; 王全杰; 王玉洁

    2012-01-01

    The present applications of nano materials in waterborne polyurethane were reviewed, as well as the synthesis mechanism and methods of waterborne polyurethanecompounding with nano materials. The research progress of nano materials in modified waterborne polyurethane was mainly introduced. The application prospects of nano materials in waterborne polyurethane was proposed.%综述了纳米材料在水性聚氨酯中的应用现状,以及与该类水性聚氨酯的作用和合成方法。着重介绍了纳米材料在改性水性聚氨酯中的研究进展,并对纳米材料在水性聚氨酯中的应用前景提出展望。

  17. 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.

  18. Emergent elemental two-dimensional materials beyond graphene

    Science.gov (United States)

    Zhang, Yuanbo; Rubio, Angel; Le Lay, Guy

    2017-02-01

    Two-dimensional (2D) materials may offer the ultimate scaling beyond the 5 nm gate length. The difficulty of reliably opening a band gap in graphene has led to the search for alternative, semiconducting 2D materials. Emerging classes of elemental 2D materials stand out for their compatibility with existing technologies and/or for their diverse, tunable electronic structures. Among this group, black phosphorene has recently shown superior semiconductor performances. Silicene and germanene feature Dirac-type band dispersions, much like graphene. Calculations show that most group IV and group V elements have one or more stable 2D allotropes, with properties potentially suitable for electronic and optoelectronic applications. Here, we review the advances in these fascinating elemental 2D materials and discuss progress and challenges in their applications in future opto- and nano-electronic devices.

  19. Cooled optical filters for Q-band infrared astronomy (15-40 μm)

    Science.gov (United States)

    Hawkins, Gary J.; Sherwood, Richard E.; Djotni, Karim; Threadgold, Timothy M.

    2016-07-01

    With a growing interest in mid- and far-infrared astronomy using cooled imaging and spectrometer instruments in highaltitude observatories and spaceflight telescopes, it is becoming increasingly important to characterise and assess the spectral performance of cooled multilayer filters across the Q-band atmospheric window. This region contains spectral features emitted by many astrophysical phenomena and objects fundamental to circumstellar and planetary formation theories. However extending interference filtering to isolate radiation at progressively longer wavelengths and improve photometric accuracy is an area of ongoing and challenging thin-film research. We have successfully fabricated cooled bandpass and edge filters with high durability for operation across the 15-30 μm Q-band region. In this paper we describe the rationale for selection of optical materials and properties of fabricated thin-film coatings for this region, together with FTIR spectral measurements and assessment of environmental durability.

  20. 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.

  1. Distribution Free Prediction Bands

    CERN Document Server

    Lei, Jing

    2012-01-01

    We study distribution free, nonparametric prediction bands with a special focus on their finite sample behavior. First we investigate and develop different notions of finite sample coverage guarantees. Then we give a new prediction band estimator by combining the idea of "conformal prediction" (Vovk et al. 2009) with nonparametric conditional density estimation. The proposed estimator, called COPS (Conformal Optimized Prediction Set), always has finite sample guarantee in a stronger sense than the original conformal prediction estimator. Under regularity conditions the estimator converges to an oracle band at a minimax optimal rate. A fast approximation algorithm and a data driven method for selecting the bandwidth are developed. The method is illustrated first in simulated data. Then, an application shows that the proposed method gives desirable prediction intervals in an automatic way, as compared to the classical linear regression modeling.

  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. 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.

  4. Exceptionally large banded spherulites

    Science.gov (United States)

    Lagasse, R. R.

    1994-07-01

    This article concerns the crystallization of maleic anhydride from a blend containing 2 wt% of poly(acrylonitrile). High speed photography and temperature measurements during the crystallization as well as X-ray diffraction from the blend after crystallization are consistent with a banded spherulitic morphology.

  5. 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)

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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。

  16. Analytic Materials

    CERN Document Server

    Milton, Graeme W

    2016-01-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer $p$. If $p$ takes its maximum value then we have a complete analytic material. Otherwise it is incomplete analytic material of rank $p$. For two-dimensional materials further progress can be made in the identification of analytic materials by using the well-known fact that a $90^\\circ$ rotation applied to a divergence free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  17. A charge distribution analysis instrument for catalysis and material science applications. Third quarterly technical progress report, April 1, 1994--June 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Freund, F.

    1994-08-05

    Key component in the CDA instrument is the differential capacitive force sensor. The CDA instrument has four basic components: OEM analytical balance, flexure point and capacitor plates, gas confinement tower and high-voltage bias electrodes, and the furnace. Phyton is in position to purchase an OEM analytical balance; negotations are underway for obtaining the feedback control circuitry for the differential capacitive force sensor. Progress with the differential capacitive force sensor is reviewed.

  18. 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

    sampling of the Brillouin zone (BZ) than is necessary for similar three-dimensional solids. Here, we use an analytical expression for the small q limit of the 2D response function to perform the BZ integral over the critical region around q = 0. This drastically reduces the requirements on the q-point mesh...... and implies a significant computational speedup. For example, in the case of monolayer MoS2, convergence of the G0W0 band gap to within similar to 0.1 eV is achieved with 12 x 12 q points rather than the 36 x 36 mesh required with discrete BZ sampling techniques. We perform a critical assessment of the band...

  19. 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.

  20. 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...

  1. Shear banding phenomena in a Laponite suspension

    CERN Document Server

    Ianni, F; Gentilini, S; Ruocco, G

    2007-01-01

    Shear localization in an aqueous clay suspension of Laponite is investigated through dynamic light scattering, which provides access both to the dynamics of the system (homodyne mode) and to the local velocity profile (heterodyne mode). When the shear bands form, a relaxation of the dynamics typical of a gel phase is observed in the unsheared band soon after flow stop, suggesting that an arrested dynamics is present during the shear localization regime. Periodic oscillations of the flow behavior, typical of a stick-slip phenomenon, are also observed when shear localization occurs. Both results are discussed in the light of various theoretical models for soft glassy materials.

  2. 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.

  3. 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.

  4. Materials compatibility and lubricants research on CFC-refrigerant substitutes. Quarterly MCLR program technical progress report, January 1, 1995--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Szymurski, S.R.; Hourahan, G.C.; Godwin, D.S.

    1995-04-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. The Air-Conditioning and Refrigeration Technology Institute, Inc., (ARTI) manages and contracts multiple research projects and a data collection and dissemination effort. Detailed results from these projects are reported in technical reports prepared by each subcontractor.

  5. Research progress and application of Li-Ni-Co-Mn-O as cathode material for lithium ion battery%锂离子电池正极三元材料的研究进展及应用

    Institute of Scientific and Technical Information of China (English)

    蔡少伟

    2013-01-01

    对近年来锂离子电池正极材料氧化镍钴锰锂的研究进展进行了综述,介绍其结构、性能特点、制备方法、电化学性能以及掺杂、包覆改性等方面的研究情况,论述了三元材料的研究现状和市场应用,环保、高能的三元材料将成为下一代动力锂离子电池的首选.%The research progress of layered Li-Ni-Co-Mn-O as cathode materials for lithium ion batteries in recent years was reviewed and the emphasis is placed on their structure,properties,synthesis methods,electrochemical performances,as well as doping and surface-modification investigation.Then,the present progress and market of research on cathode material Li-Ni-Co-Mn-O were studied.The environment-friendly and high energy ternary materials will become the first choice for the next power lithium ion battery.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 锂离子电池电极材料的研究进展%Progress in research on materials for lithium- ion batteries

    Institute of Scientific and Technical Information of China (English)

    付文莉

    2009-01-01

    The paper researched the development of lithium-ion battery electrode materials, and introduced the cathode material and anode material for most. It pointed out that the future will focus on research and development of electrode materials toward high specific capacity, high charge-discharge efficiency, high-cycle performance and cost-effective direction.%综述了锂离子电池电极材料的研究进展,介绍了正极材料和负极材料.指出今后电极材料的研究与开发重点将朝着高比容量、高充放电效率、高循环性能以及低成本方向发展.

  11. Macro-encapsulation of heat storage phase-change materials for use in residential buildings. First quarterly progress report, September 29--December 29, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Lane, G.A.; Kott, A.C.; Rossow, H.E.

    1977-02-01

    Objectives are to assess the feasibility of macro-encapsulated PCM's for residential solar systems, to develop and evaluate such materials. Five PCM's have been selected from encapsulation studies. Encapsulated storage media were evaluated theoretically in storage beds with air and water as the heat transfer medium. Cylindrical, tetrahedral, and pillow shapes are being evaluated for the encapsulated PCM. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles.

  12. Research Progress on Manganese Dioxide Electrode Materials for Electrochemical Capacitors%电化学电容器中二氧化锰电极材料研究进展

    Institute of Scientific and Technical Information of China (English)

    李四横; 刘庆鹤; 齐力; 逯乐慧; 王宏宇

    2012-01-01

    本文在简介MnO2电极材料的性质和特点基础上,重点介绍近5年来国内外有关MnO2电极材料在合成及电化学电容器应用领域中的最新进展,及未来可能的发展方向.%Based on presenting the intrinsic characteristics of manganese dioxide electrode materials,the research progress of preparation and its application for electrochemical capacitor were introduced in this article. Moreover, the future development trend is prospected.

  13. Progress in high-energy ball milling for the preparation of absorbing materials%吸波材料的高能球磨工艺研究进展

    Institute of Scientific and Technical Information of China (English)

    王锰刚; 谌静; 谢国治; 陈文俊; 李艳; 张泽敖; 王嘉波; 沈杨; 孙康; 周倜

    2016-01-01

    High-energy ball milling method has become a important way to prepare various absorbing materials, because of simple control, environmental production, low cost and high efficiency. This paper summarizes the recent research progress of high-energy ball milling process in absorbing materials,indicating that high-energy ball milling process in absorbing materials, especially in flaky absorbing materials with shape anisotropy, which has very broad application prospects. Then we look forward to the development prospects of high-energy ball milling process in absorbing materials.%高能球磨法由于其便于控制、生产环保、成本低、效率高等优点成为制备吸波材料的一种重要方法。总结了近期高能球磨工艺在吸波材料领域的应用研究进展,表明高能球磨工艺在吸波领域,尤其是在制备具有形状各向异性的片状吸波材料领域,具有十分广阔的应用前景,展望了高能球磨工艺在未来吸波材料领域的发展前景。

  14. On the Progress of Implantation Materials and its Biological Evaluation%植入材料及其生物相容性评价的研究进展

    Institute of Scientific and Technical Information of China (English)

    王涵; 王春仁; 周小婷; 王召旭

    2014-01-01

    随着现代材料科学、生命科学以及医学科学的发展,植入材料在临床医学领域的应用日趋广泛,对其进行合理的临床前生物相容性评价是确保人体安全应用的前提。本文将就植入材料的进展及其生物相容性评价的特点、研究现状及发展趋势作简要评述。%With the development of modern material science, life science and medical science, implantation materials have been widely used in clinical ifelds. Proper biological evaluation of implantation materials is an essential prerequisite to ensure the safety use in human beings before clinical applications. This paper reviewed the characteristics, present condition and tendency on the biological evaluation of implantation materials. Here we also summarize the progress of implantation materials.

  15. 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.

  16. 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.

  17. Solar collectors. Technical progress report No. 1, September 5, 1978-March 5, 1979. [Listing of glazings, housing materials, acrylic coatings, etching processes and AR coatings

    Energy Technology Data Exchange (ETDEWEB)

    Baum, B.; Gage, M.

    1979-04-27

    A broad information search was carried out in four areas: glazings, housing materials, acrylic coatings, etching processes and AR coatings. An extensive list of all (known) US transparent polymers was developed as well as tables of plastic, ceramic and metallic materials that could conceivably function as a housing. In addition, a compilation was made of commercially available solvent and water-base acrylic coatings for use as a uv protective coating for the glazing. Eighteen transparent polymers were chosen as possible glazings and twelve materials (plastic and wood) as possible housings and exposed in the Weather-Ometer as tensile bars and for the glazings as disks for optical transmission. These same materials were also exposed on our roof to monitor soiling. A variety of solvent and water-base acrylics were selected as protective coatings and ordered. Two commercial films - Tedlar 20 and Halar 500 - with strong absorption in the uv and two commercial films containing uv absorbers - Tedlar UT and Korad 201R - were laminated by several different processes to four promising glazing materials: polyvinyl fluoride (Tedlar), polymethyl methacrylate (Plexiglass), crosslinked ethylene/vinyl acetate and thermoplastic polyester (Llumar). A variety of etching processes were briefly explored and AR coating studies started on the above four glazing films.

  18. Band structures in the nematic elastomers phononic crystals

    Science.gov (United States)

    Yang, Shuai; Liu, Ying; Liang, Tianshu

    2017-02-01

    As one kind of new intelligent materials, nematic elastomers (NEs) represent an exciting physical system that combines the local orientational symmetry breaking and the entropic rubber elasticity, producing a number of unique physical phenomena. In this paper, the potential application of NEs in the band tuning is explored. The band structures in two kinds of NE phononic crystals (PCs) are investigated. Through changing NE intrinsic parameters, the influence of the porosity, director rotation and relaxation on the band structures in NE PCs are analyzed. This work is a meaningful try for application of NEs in acoustic field and proposes a new intelligent strategy in band turning.

  19. Materials Compatibility and Lubricants Research of CFC-refrigerant substitutes. Quarterly technical progress report, 1 April 1993--30 June 1993

    Energy Technology Data Exchange (ETDEWEB)

    Godwin, D.S.; Hourahan, G.C.; Szymurski, S.R.

    1993-07-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The DCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. Under the current MCLR program the Air-Conditioning and Refrigeration Technology Institute, Inc., (ARTI) is contracting and managing multiple research projects and a data collection and dissemination effort. Detailed results from these projects are reported in technical reports prepared by each researcher.

  20. 赤泥改性复合材料的研究概况%Progresses of Modified Red Mud Composite Material

    Institute of Scientific and Technical Information of China (English)

    栾中岳

    2012-01-01

    The physical and chemical properties of red mud composite material were analyzed, rrom classification, structure, properties, preparation method, and application, the research of this material in recent years was introduced. Problems and future development direction of modified red mud composite material were pointed out.%分析了赤泥的物理化学性质,从分类、结构、性能、制备、应用五个方面介绍了近年来国内外关于赤泥改性复合材料的研究概况。指出目前赤泥改性复合材料存在的问题与未来发展方向。

  1. The development of a friction model predicting the sliding behavior of materials pairs, especially at low temperatures: Progress report and renewal proposal

    Energy Technology Data Exchange (ETDEWEB)

    Iwasa, Yukikazu; Rabinowicz, E.

    1987-03-09

    Principal objective of this renewal proposal is to develop a friction model which predicts whether a sliding system will give steady or unsteady sliding behavior at low speeds and to advance the basic understanding of the friction process. The proposed program consists of experimental and analytical studies. Experimental work will include collecting data on the material properties of the two contacting materials, namely the bulk creep behavior in tension and interfacial creep data in shear. These data will be collected both at room temperature, and at cryogenic temperatures. Interfacial creep takes place when one material is pressed against the other by a constant force and a shear force insufficient to cause gross sliding is applied. The extent to which the bulk creep properties affect the interfacial creep behavior will be determined, and this knowledge will lead to better models of the friction process.

  2. Progress in application of graphene in Li-ion battery cathode materials%石墨烯在锂离子电池正极材料中应用的进展

    Institute of Scientific and Technical Information of China (English)

    吕璐; 洪建和; 何岗; 何明中

    2012-01-01

    Research progress in graphene composite with cathode materials such as polyanionic,spinel and layered structure to improve the electrochemical performance of Li-ion battery was reviewed. The problems in application of graphene in Li-ion battery cathode materials were summarized.%综述了石墨烯与聚阴离子型、尖晶石型、层状结构的正极材料复合,改善锂离子电池电化学性能的研究进展.总结了石墨烯在锂离子电池正极材料中的应用所面临的问题.

  3. Research Progress of Material Selection and Protection Technology on Oil and Gas Pipeline%油气管道选材及防护技术的研究进展

    Institute of Scientific and Technical Information of China (English)

    孙方红; 马壮; 宋晓龙; 刘应瑞; 李福永

    2013-01-01

    The research progress of common materials on the oil and gas pipeline was summarized. The research results of macromolecular compound coating, glass coating, metal coating, corrosion inhibitor and cathodic protection were reviewed. The merits and demerits of different protection technologies were analyzed. The development trends of material selection and protection technology on oil and gas pipeline were proposed.%叙述了油气管道常用材料的研究现状;介绍了高分子化合物涂料、玻璃涂层和金属镀层、缓蚀剂、阴极保护等防护措施的研究成果;分析了各种防护技术的优缺点;展望了今后油气管道选材和防护措施的发展方向.

  4. Research progress of anode material for sodium-ion batteries%钠离子电池负极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨绍斌; 董伟; 沈丁; 李思南; 王中将; 张佳民; 孙闻; 张琴

    2016-01-01

    The research status of anode materials in recent years, such as carbons, alloys, metal oxides and soon,were summarized, the performance and storage mechanism of sodiumofthe materials reachedwere introduced. The main problems of these kinds of anode materialsand the solutionwere discussed.The research directions and prospects on anode materialswereforecasted, and thecarbon materials with large layer spacing and less surface area is the most promising candidate anode material for sodium ion battery,and titanate with good structure stability is potential anode materials. Designing and developingnew materials is an important future research field for sodium ion battery.%综述近年来国内外对于碳、合金、金属氧化物等负极材料的研究现状,重点介绍材料的性能以及储钠机理,探讨材料存在的主要问题和解决方法,对负极材料的研究方向以及前景进行展望,指出具有较大层间距和较小比表面积的碳材料是目前最有希望应用于钠离子电池的负极材料,结构稳定性较好的钛酸盐材料是极具潜力的负极材料,设计开发适合的离子电池自身特点的新材料是未来钠电子电池研究的重要方向。

  5. Propulsion materials

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Edward J. [U.S. Dept. of Energy, Washington, D.C. (United States); Sullivan, Rogelio A. [U.S. Dept. of Energy, Washington, D.C. (United States); Gibbs, Jerry L. [U.S. Dept. of Energy, Washington, D.C. (United States)

    2008-01-01

    The Department of Energy’s (DOE’s) Office of Vehicle Technologies (OVT) is pleased to introduce the FY 2007 Annual Progress Report for the Propulsion Materials Research and Development Program. Together with DOE national laboratories and in partnership with private industry and universities across the United States, the program continues to engage in research and development (R&D) that provides enabling materials technology for fuel-efficient and environmentally friendly commercial and passenger vehicles.

  6. Progress Report

    DEFF Research Database (Denmark)

    Duer, Karsten

    1999-01-01

    Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999.......Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999....

  7. Recent Research Progress on the Mg2Si Based Thermoelectric Materials%Mg2Si基热电材料的制备与掺杂研究现状

    Institute of Scientific and Technical Information of China (English)

    曹萌萌; 周园; 任秀峰; 年洪恩; 李翔

    2012-01-01

    Thermoelectric materials can convert electricity into heat reversible directly. It is a material which has a superior performance with a environment-friendly property. Mg2Si based semiconductor is one of the most promising material among the entire semiconductor materials which are nontoxic and cheap. It has a potentially high dimensionless figure of merit ZT. And it is very difficult to synthesize Mg2Si alloy because of the high activity of magnesium. So it becomes the researching key about how to synthesize high performance Mg2Si based thermoelectric materials. In this paper, the basic properties had been briefly introduced, the preparation methods and the doping of Mg-Si based thermoelectric materials and its research progress had been reviewed. Based on the introduction of the various synthetic methods, the advantages and disadvantages of these methods as well as how to improve them were summarized. Whats more, the development direction of thermoelectric materials had been prospected.%热电材料是一种性能优越的环境友好型材料,它能够直接把电能和热能相互转化,是目前新技术能源材料领域的关键材料.Mg2Si基半导体是一种新型的中温区热电材料,具有热电值高,原料无毒害等优点,由于镁的活性较高,如何制备出性能更加优良的Mg2Si基块体热电材料成为本领域研究的重点.本文简要介绍了Mg2Si基热电材料的基本性质,阐述其各种制备方法和掺杂研究现状,并展望其未来研究方向.

  8. Recent progress in material study and photovoltaic device of Sb2Se3%新型硒化锑材料及其光伏器件研究进展∗

    Institute of Scientific and Technical Information of China (English)

    薛丁江; 石杭杰; 唐江

    2015-01-01

    Recently, antimony selenide (Sb2Se3) has been proposed as an alternative earth-abundant absorber material for thin film solar cells. Sb2Se3 is a simple V2-VI3 binary compound with an orthorhombic crystal structure and a space group of Pnma 62. It is a staggered, layered compound consisting of parallel 1D (Sb4Se6)n ribbons held together by weak van der Waals forces. Sb2Se3 has a direct band gap of approximately 1.15 eV with a large absorption coefficient (>105 cm−1, at short wavelength) and a low grain growth temperature (∼300◦C), facilitating the fabrication of low-cost thin film solar cells. Moreover, it is a simple binary compound in single phase with a fixed composition, which provides a much simpler growth chemistry than the multicomponent Cu2ZnSn(S,Se)4. In addition, it is stable upon exposure to the ambient air, thus having a better prospect for long-term stability than the organic-inorganic halide perovskite solar cells. Theoretical analysis indicates that the efficiency limit is>30%for single junction Sb2Se3 solar cells. Various approaches, including vacuum evaporation, electrodeposition, spray pyrolysis, and chemical bath deposition (CBD), have been explored to produce Sb2Se3 thin films;however, it is only in these years that Sb2Se3 solar cells have been reported by our group as well as by others. Seok’s group presented the deposition of Sb2Se3 on mesoporous TiO2 films by thermal decomposition of Sb2Se3 single-source precursors, and fabricated Sb2Se3-sensitized inorganic-organic heterojunction solar cells with a remarkable efficiency of 3.21%. Tena-Zaera’s group fabricated the FTO/TiO2/Sb2Se3/CuSCN/Au heterojunction device and achieved 2.1% device efficiency; their Sb2Se3 was obtained by an electrodeposition route and CuSCN served as a hole conducting layer. Different from the above Sb2Se3-sensitized solar cells reported by other groups, our group is the first in the world working on Sb2Se3 thin film solar cells so far as wu know. We have

  9. The Wulf bands of oxygen

    Science.gov (United States)

    Bernath, Peter; Carleer, Michel; Fally, Sophie; Jenouvrier, Alain; Vandaele, Ann Carine; Hermans, Christian; Mérienne, Marie-France; Colin, Reginald

    1998-11-01

    The Wulf bands of oxygen in the 240-290 nm spectral region are caused by collision-induced absorption of the Herzberg III ( A' 3Δu- X3Σ-g) system. These bands had been previously attributed to the oxygen dimer, (O 2) 2. Under atmospheric conditions the Wulf bands are thus the long-wavelength extension of the Herzberg continuum. Absorption of solar radiation by the Wulf bands may be an additional source of NO in the stratosphere.

  10. Application progress of functional polymer material in adhesives%功能高分子材料在胶粘剂中的应用进展

    Institute of Scientific and Technical Information of China (English)

    崔瑾; 胡孝勇; 柯勇; 姜青松

    2014-01-01

    The types and features of functional polymer materials were briefly introduced. The applications of various functional polymer materials(such as heat-conducting,electric,magnetic,photosensitive,ion exchange resin,high water absorbability,flocculation,photoinitiator,high temperature resistant,shape memory and other materials) in adhesives were particularly reviewed. Finally,the unique functions and application prospect of functional polymer materials in adhesive were expected.%简单介绍了功能高分子材料的种类和特点,特别就其各类功能高分子材料(如导热、导电、磁性、光敏、离子交换树脂、高吸水性、絮凝、光引发、耐高温和形状记忆等材料)在胶粘剂领域中的应用进行了综述。最后对功能高分子材料在胶粘剂中的独特作用和应用前景进行了展望。

  11. PVC涂层膜材料老化研究进展%Progress of Study on the Aging of PVC-Coated Membrane Material

    Institute of Scientific and Technical Information of China (English)

    闫永生; 杨旭东; 丁辛; 胡淳

    2012-01-01

    The photo-oxidation mechanisms of PVC-coated membrane material is briefly explained. Both artificial accelerated and outdoor exposure tests on PVC-coated membrane material and standards related to PVC-coated membrane material as well as some testing methods after aging are introduced systematically. Finally the research of status quo and existing problems of the correlation between results from artificial accelerated ageing and that from outdoor ageing of PVC-coated membrane material are analyzed.%介绍了PVC涂层膜材料的光氧老化机理;系统地介绍了人工加速老化试验和自然老化试验方法及参照的国内外标准,并对材料老化后的测试方法做了介绍;最后分析了PVC膜材料在人工加速老化试验和自然老化试验下的相关性的研究现状及存在的问题.

  12. 石墨烯/聚氨酯复合功能材料研究进展%The research progress of graphene/polyurethane composite functional materials

    Institute of Scientific and Technical Information of China (English)

    罗晓民; 葛炳辉; 李维虎; 冯见艳; 张鹏; 曹敏

    2015-01-01

    Graphene has a unique two‐dimensional structure and excellent thermal conductivity and electrical conductivity .Synthesis of composite material with polyurethane is a kind of new functional polymer material and the composite material has wide application prospect .This paper reviewed the preparation methods of gra‐phene and polyurethane composite materials ,as well as the application of the self‐healing ,UV curing ,shape memory ,conductive ,electromagnetic shielding ,anti‐UV and biocompatibility .%石墨烯具有独特的二维结构和优良导热、导电特性,可与聚氨酯复合成一种新型功能高分子材料,具有广泛的应用前景。综述了石墨烯与聚氨酯复合材料的制备方法以及在自修复、UV 固化、形状记忆、导电、电磁屏蔽、防紫外线和生物相容性等领域的应用。

  13. The Research & Application Progress of Sodium Silicate Composite Materials%水玻璃复合材料应用研究的进展

    Institute of Scientific and Technical Information of China (English)

    康永; 侯晓辉; 柴秀娟

    2011-01-01

    Sodium silicate composite materials was a recyclable, energy-conserving, eco-friendly and high-environmental protection material.It will be aroused favorable market benefit to research sodium silicate eco-friendly composite materials under the conditions of advocating for "energy saving and pollution alleviation "by the nation.It was summarized the sodium silicate composite materials properties, modifications, hardening-mechanism and application fields in this thesis.%水玻璃复合材料是一种利废、节能、低污染的绿色材料,在国家提倡的"节能减排"的新形势下,研究和应用水玻璃环境友好型材料必然会创造较好的市场效益.文中浅显论述了水玻璃的特性、改性、硬化机理和相应的应用领域.

  14. Progress of All-nitrogen Ultrahigh-energetic Materials%全氮型超高能含能材料研究进展

    Institute of Scientific and Technical Information of China (English)

    李玉川; 庞思平

    2012-01-01

    从合成和理论方面综述了全氮型超高能含能材料的研究进展.介绍了从N3到N13、N60、聚合氮(Cg- N)等氮簇含能材料的合成及理论研究情况,总结了各种全氮结构的特点以及在全氮型含能材料合成和理论研究中面临的技术问题,指出了部分全氮型含能材料的研究发展趋势.附参考文献61篇.%The recent developments of all-nitrogen ultrahigh-energetic materials in both experiment and theory were reviewed. The synthesis and theoretical calculation of nitrogen cluster energetic materials from N3 to N13,N60 and cubic gauche nitrogen(Cg-N) , etc were introduced. The characteristics of various all-nitrogen structures and the key issues faced with synthesis and theoretical research of all-nitrogen energetic materials were summarized. The development trends of all-nitrogen ultrahigh-energetic materials were pointed out with 61 references.

  15. HTGR Generic Technology Program: materials technology reactor; operating experience; medium-enriched-uranium fuel development. Quarterly progress report for the period ending July 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-01

    The work reported includes the development of the materials properties data base for noncore components, plant surveillance and testing performed at Fort St. Vrain, and work to demonstrate the feasibility of using medium-enriched fuel in Fort St. Vrain. Studies and analyses plus experimental procedures and results are discussed and data are presented.

  16. HTGR Generic Technology Program. Materials technology reactor operating experience medium-enriched-uranium fuel development. Quarterly progress report for the period ending April 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Kaae, J. L.; Lai, G. Y.; Thompson, L. D.; Sheehan, J. E.; Rosenwasser, S. N.; Johnson, W. R.; Li, C. C.; Pieren, W. R.; Smith, A. B.; Holko, K. H.; Baenteli, G. J.; Cheung, K. C.; Orr, J. D.; Potter, R. C.; Baxter, A.; Bell, W.; Lane, R.; Wunderlich, R. G.; Neylan, A. J.

    1978-05-01

    The work reported includes the development of the materials properties data base for noncore components, plant surveillance and testing performed at Fort St. Vrain, and work to demonstrate the feasibility of using medium-enriched fuel in Fort St. Vrain. Studies and analyses plus experimental procedures and results are discussed and data are presented.

  17. Design and Fabrication of a Kind of Far Infrared and 10.6 μm Laser Band Compatible Camouflage Material Based on Photonic Crystals%一种基于光子晶体的远红外与10.6μm激光兼容伪装材料的设计与制备

    Institute of Scientific and Technical Information of China (English)

    高永芳; 时家明; 赵大鹏; 汪家春

    2011-01-01

    Due to the change of modern detecting systems from the single working mode to the compound workingone, materials with special spectral characteristics are required to meet camouflage demands. As a new kind of man-made structural function material, photonic crystals can realize thermal infrared camouflage because of its high-reflection photon forbidden band. Based on one-dimensional doped photonic crystal, a kind of far infrared and laser band compatible camouflage material is designed, then the transmission spectrum is calculated by characteristic matrix method of thin-film optical theory. The sample of photonic crystal is fabricated. It is found that the actual testing curve is coincident with the theoretic design curve. The result shows that one-dimensional doped photonic crystal can achieve far infrared and laser band compatible camouflage.%现代探测系统由单一工作模式到复合工作模式的转变,对伪装材料的光谱特性提出了某些特殊要求.作为一种新型人工结构功能材料,光子晶体基于光子禁带的高反射特性可以实现热红外伪装.设计了一种基于一维掺杂光子晶体的远红外与激光兼容伪装材料,利用薄膜光学理论的特征矩阵法计算了透射光谱.制备的样品经测试,与理论曲线相吻合.结果表明,利用一维掺杂光子晶体可以实现远红外与激光兼容伪装.

  18. 药用高分子材料亲水性修饰的研究进展%Research Progress in Hydrophilic Modified of Pharmaceutic Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    王典; 尹华月; 鲁传华

    2013-01-01

    高分子材料在药物制剂和制药工艺上具有广泛的应用价值.新型制剂的研发与药用高分子材料的性能密切相关,特别是高分子胶束等两亲性高分子材料的使用尤为广泛,也是高分子材料当今研究的热点.本文着重对常见药用高分子材料亲水性修饰的亲水片段进行了概括总结.根据亲水片段的大小,分为小分子修饰、水溶性聚合物修饰以及水溶性高分子修饰三个部分,对药用高分子材料亲水修饰的修饰剂和修饰产物的性质特点、修饰方法以及其中的优势和不足尽可能的进行了综述,并对此进行了讨论和展望,以期能够给同行们提供参考并共讨论.%Polymer materials has a wide range of application value in pharmaceutic preparation pharmaceutical processes. The research and development of new pharmaceutical manufacturing is intimately related to the property of pharmaceutic polymer materials .especially amphiphilic high molecular materials are widely used in the research and development of new pharmaceutical manufacturing and they are also the research hotspots > such as polymeric micelles. The common hydrophilic segments of amphiphilic pharmaceutic polymer materials are summarized in this paper, on the basis of size of hydrophilic segments, hydrophilic modification of pharmaceutic polymer materials is divided three classes-water-soluble micromolecules modified, water-soluble polymers modified and water-soluble high molecular materials modified, in order to give references to colleagues and discuss, the characteristics of the modifier and modified products and modification methods from the hydrophilic modification of pharmaceutic polymer materials and the advantages and disadvantages of modifier are reviewed as comprehensive as possible in this paper, at the same time, it is discussed and prospected.

  19. 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.

  20. An innovative band-to-band tunneling analytical model and implications in compact modeling of tunneling-based devices

    Science.gov (United States)

    De Michielis, L.; Daǧtekin, N.; Biswas, A.; Lattanzio, L.; Selmi, L.; Luisier, M.; Riel, H.; Ionescu, A. M.

    2013-09-01

    In this paper, an analytical band-to-band tunneling model is proposed, validated by means of drift-diffusion simulation and comparison with experimental data, implemented in Verilog-A, and finally proven with SPICE simulator through simulation of circuits featuring tunneling diodes. The p-n junction current calculation starts from a non-local Band-to-Band tunneling theory including the electron-phonon interaction and therefore it is particularly suited for indirect semiconductor materials such as silicon- or germanium-based interband tunneling devices.

  1. 电磁缺陷修复材料研究进展%Research Progress of Repairing Materials of Electromagnetic Discontinuities

    Institute of Scientific and Technical Information of China (English)

    陈海燕; 谢建良; 周佩珩; 陆海鹏; 邓龙江

    2013-01-01

    The theory, application and development of electromagnetic discontinuities repairing materials in scattering controlling of electromagnetic discontinuities such as edge, gaps and grooves and steps are described.The definition and characteristic of surface electromagnetic discontinuities are analyzed , and the theory and methods for repairing electromag-netic discontinuities are also proposed.Electromagnetic discontinuities repairing materials including magnetic materials for suppression of surface wave, conductive materials for repairing the narrow gaps or grooves, and the tapered impedance ma-terials for controlling edge scattering are discussed respectively, and one of which, the tapered impedance materials are il-lustrated particularly.The tapered resistive materials realized by geometric variation based on frequency-selective surfaces concepts is demonstrated having good suppression of edge scattering from a triangular metallic plate .Electromagnetic back-scattering of the as-prepared target from a triangular plate with edge tapered resistive sheet loading is proposed for both hor-izontal polarization and vertical polarization, and compared with that from the one of the same shape but loaded with serra-ted shaping or none resistive sheet on the edge .The results show that the tapered impedance materials can regulate effec-tively edge scattering by choosing the appropriate materials and devising the reasonable gradient impedance .Some view-points of the tapered impedance material ’ s future application in electromagnetic scattering and electromagnetic radiation domains are proposed.%研究了电磁缺陷修复材料在飞行器边缘、缝隙等表面电磁缺陷散射控制中的应用,阐述了其原理和发展状况。给出了表面电磁缺陷的基本定义,分析了其散射特点,并提出电磁缺陷修复原理及基本方法。电磁缺陷修复材料主要包括用于表面波抑制的磁性材料、用于窄缝隙保证电连续的导电

  2. 电磁波吸收建筑材料的应用研究进展%Recent Progress in Electromagnetic Wave Absorbing Building Materials

    Institute of Scientific and Technical Information of China (English)

    解帅; 冀志江; 杨洋; 王静

    2016-01-01

    Application of electromagnetic wave (EMW)absorbing building materials is an effective method to improve the electromagnetic environment of architectural space.And the EMW absorbing material has been a hot area of research in recent years,as the electromagnetic radiation pollution increasing seriously.The recent advances and re-search methods of EMW absorbing building materials are reviewed in this paper.The materials are summarized as two major categories:filling absorbing agent and structure design,and then the shortcoming of current studies and approa-ches for further researchers are suggested after the review.Design of the ideal absorbing building materials with the characteristics of low density,thin matching thickness,broad bandwidth and strong microwave wave absorption,is the main direction,and the mechanism of wave absorption should be researched in depth.%应用电磁波吸收建筑材料是改善建筑空间电磁环境的有效方法。随着电磁辐射污染日益严重,吸波建材已逐渐成为研究热点。综述了近几年吸波建材的研究方法与研究现状,将吸波建材归纳为吸波剂填充型和结构设计型两大类,并分别进行评述,提出了现有研究中存在的一些问题以及进一步的研究方向。“轻、薄、宽、强”仍然是吸波建材的发展方向,同时电磁波损耗机理还有待进一步研究。

  3. Fundamentals and applications of magnetic materials

    CERN Document Server

    Krishnan, Kannan M

    2016-01-01

    Students and researchers looking for a comprehensive textbook on magnetism, magnetic materials and related applications will find in this book an excellent explanation of the field. Chapters progress logically from the physics of magnetism, to magnetic phenomena in materials, to size and dimensionality effects, to applications. Beginning with a description of magnetic phenomena and measurements on a macroscopic scale, the book then presents discussions of intrinsic and phenomenological concepts of magnetism such as electronic magnetic moments and classical, quantum, and band theories of magnetic behavior. It then covers ordered magnetic materials (emphasizing their structure-sensitive properties) and magnetic phenomena, including magnetic anisotropy, magnetostriction, and magnetic domain structures and dynamics. What follows is a comprehensive description of imaging methods to resolve magnetic microstructures (domains) along with an introduction to micromagnetic modeling. The book then explores in detail size...

  4. Research progress in hydrotalcite filled material based on polyvinyl chloride%水滑石填充聚氯乙烯材料研究进展

    Institute of Scientific and Technical Information of China (English)

    张强; 吕杰彬

    2001-01-01

    The thermal stability and other noble properties of polyvinyl chloride(PVC)can be markedly improved and contributed by filling with hydrotalcite and other thermal stabilizers in.The characteristics and applications of hydrotalcite and progress in its filled PVC were discussed.The application prospect of hydrotalcite in China's PVC industry was outlined.%水滑石在与其他热稳定剂复配作为聚氯乙烯(PVC)热稳定剂时,除可显著提高PVC热稳定性外,还可赋予PVC材料一些其他优异的性能。本文介绍了水滑石的性质和用途及水滑石填充PVC材料研究进展,并展望了水滑石在我国PVC工业中的应用前景。

  5. A study of the source materials, depositional environments, mechanisms of generation and migration of oils in the Anadarko, Oklahoma. Progress report, September 15, 1990--September 14, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Philp, R.P.

    1990-04-20

    This report is for the final year of a three-year funded project. A new proposal has been submitted and it is hoped that funding will continue for another three years. It is felt that good progress is being made with our work on studying the oils and source rocks in the Anadarko Basin. Furthermore a number of associated projects have evolved during this period which have also produced many useful results and various analytical methods have been developed. In Appendix I lists of students totally or partially supported by this work plus various publications are given. It is hoped that these will testify to our productivity arising from the DOE support over the past few years.

  6. Progress in Research of Iron Oxide Composite Anode Materials for Li-ion Battery%氧化铁基锂离子电池负极材料研究进展

    Institute of Scientific and Technical Information of China (English)

    田嘉铭; 王静; 杨金萍; 赵清清

    2014-01-01

    铁氧化物负极材料具有理论容量高、放电平台低、合成方法简单、对环境友好等特点,受到研究者的关注。综述了铁氧化物负极材料在锂离子电池中的应用、制备方法等方面的最新研究进展,介绍了提高铁氧化物材料电化学性能的方式,提出铁氧化物负极材料可望提高锂离子电池的综合性能。%The more attention has been paid to the iron oxide anode materials for lithium ion battery due to their special characteristics such as higher theoretical capacity, low discharge potential, simple synthesis methods and friendly to the environment.Recent progress was reviewed on the applications, preparation methods of iron oxide anode materials in lithium ion batteries.The method of increasing the electrochemical performance was introduced.The iron oxide anode materials is hopeful to increase the gen-eral performances of lithium ion battery materials.

  7. Progress in the Research on Materials of Fire Proof Layer of Fire Resistant Cable%耐火电缆耐火绝缘层材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    邵海彬; 张其土; 魏方明; 王庭慰

    2011-01-01

    Insulating material composition, material selection, performance and research progress of the three types of fire-resistant insulating layer materials are described. There are obvious disadvantages in production, installation and price of fire-resistant cables using mica tape and magnesium hydroxide (MgO) as fire-resistant insulating layer. While there are obvious advantages in production, installation and price of fire-resistant cables using fast ceramilying fire-resistant layer as fire-resistant insulating layer. Further more, research work in material selection and new product development should be reinforced.%介绍了不同类型耐火绝缘层材料的组成、材料选择、性能特点及研究概况.分析认为以云母带和氧化镁为耐火绝层缘材料制备耐火电缆在生产、安装施工、成本等方面存在明显不足,而快速陶瓷化耐火绝缘层材料在生产、安装施工、成本等方面优点突出.进一步指出,应在材料选择、新产品开发等方面加强对快速陶瓷化耐火绝缘层的研究.

  8. Progress in the Research on Materials of Fire Proof Layer of Fire Resistant Cable%耐火电缆耐火绝缘层材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    邵海彬; 张其土; 魏方明; 王庭慰

    2012-01-01

    介绍了不同类型耐火绝缘层材料的组成、材料选择、性能特点及研究概况.分析认为以云母带和氧化镁为耐火绝层缘材料制备耐火电缆在生产、安装施工、成本等方面存在明显不足,而快速陶瓷化耐火绝缘层材料在生产、安装施工、成本等方面优点突出.进一步指出,应在材料选择、新产品开发等方面加强对快速陶瓷化耐火绝缘层的研究.%Insulating material composition, material selection, performance and research progress of the three types of fire-resistant insulating layer materials are described. There are obvious disadvantages in production, installation and price of fire-resistant cables using mica tape and magnesium hydroxide (MgO) as fire-resistant insulating layer. While there are obvious advantages in production, installation and price of fire-resistant cabtes using fast cerami-fying fire-resistant layer as fire-resistant insulating layer. Further more, research work in material selection and new product development should be reinforced.

  9. 煤沥青作为筑路材料的研究进展%Progress of the Study on Coal Tar Pitch as a Road Paving Material

    Institute of Scientific and Technical Information of China (English)

    赵普; 薛永兵; 李秉正; 曹东伟; 张海燕

    2012-01-01

    The composition and properties of the coal tar pitch (CTP) were reviewed and the advantages and disadvantages of the CTP used as road paving material was discussed in this paper. To improve the properties mentioned above, a modified paving material combining coal tar pitch with petroleum asphalt was investigated, and its application prospect was discussed.%简述了煤沥青的组成和性质,综述了煤沥青改性后用作筑路材料、煤沥青和石油沥青混合料用作筑路材料的研究进展及其毒性防治,展望了筑路用煤沥青材料的研究新方向及应用前景.

  10. Application and Research Progress of Polyurethane Materials for Automobile%汽车用聚氨酯材料的应用与研究进展

    Institute of Scientific and Technical Information of China (English)

    刘文济; 涂伟萍; 王锋; 陈军

    2015-01-01

    介绍了聚氨酯( PU)材料在汽车工业上的应用现状及研究进展,重点介绍了应用最为广泛的PU泡沫塑料、弹性体、胶粘剂、涂料和PU革。指出了汽车用PU材料未来发展方向。%The present application situation and the development of some kinds of polyurethane materials for automobile industry were introduced. The polyurethane foam, polyurethane elastomer, polyurethane adhesive, poly⁃urethane coatings and polyurethane leather were introduced emphatically. The future developing direction of polyu⁃rethane materials for automobiles was pointed out.

  11. Macro-encapsulation of heat storage phase-change materials for use in residential buildings. Seventh quarterly progress report, March 29, 1978-June 29, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Lane, G.A.; Warner, G.L.; Hartwick, P.B.; Rossow, H.E.

    1978-08-01

    Objectives are to assess the feasibility of macro-encapsulated PCM's for residential solar systems, to develop and evaluate such materials. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles. Studies of the storage capability of CaCl/sub 2/.6H/sub 2/O encapsulated in polyethylene bottles, Mg(NO/sub 3/)/sub 2/6H/sub 2/O in steel cans, and Mg(NO/sub 3/)/sub 2/6H/sub 2/O/NH/sub 4/NO/sub 3/ eutectic, encapsulated in flexible plastic film packages, have been completed in the sub-scale storage test unit. The next PCM to be studied is NH/sub 4/Br/urea eutectic in polypropylene bottles.

  12. Adsorption and diffusion of fluids in well-characterized adsorbent materials. Renewal progress report, August 1, 1995 to January 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Gubbins, Keith E.; Cracknell, R.F.; Maddox, M.; Nicholson, D.

    1999-08-01

    This is an invited review paper describing recent advances in molecular simulation and theory of fluids confined within well-characterized porous materials. Methods and intermolecular potential models are described. This is followed by showing results for several examples, including supercritical methane adsorption in carbons, adsorption and diffusion of argon in VPI-5, adsorption of argon in silicalite-1, nitrogen adsorption in MCM-41, and adsorption of argon and nitrogen in carbon nanotubes.

  13. 现代混凝土材料微观结构研究进展%Research Progress on Microstructure of Modern Concrete Materials

    Institute of Scientific and Technical Information of China (English)

    周崇松; 邓斌

    2016-01-01

    The researched advances on the microstructure of modern concrete materials were reviewed from the perspective of Computational Chemistry. Firstly the nano-scale microstructure composition and structure of concrete were introduced, and the impacts of hydrogen bond in microstructure on performance of concrete were interpreted. Then the impacts of fly ash and other doped alumina slag on concrete material structure and performance were discussed. Finally the carbonization process and the carbonization mechanism of a new type of carbonized concrete material were analyzed comparatively. The summary of low-scale structure of modern concrete materials could provide in-depth understanding for engineering techniques.%文章主要从计算化学的角度对现代混凝土材料相关的研究进展进行了综述。首先介绍了混凝土在纳米尺度上的微观组成与结构,以及氢键对其性能的影响;然后讨论了粉煤灰等高铝矿渣的掺杂对混凝土材料结构与性能的影响;最后对新型的混凝土材料的碳化过程和碳化机理进行了比较分析。混凝土材料低尺度结构的总结,为现代混凝土材料的工程技术提供了深入的认识,具有一定的现实指导意义。

  14. 纤维素基高吸水材料研究进展%Research progress in cellulose-based super absorbent material

    Institute of Scientific and Technical Information of China (English)

    马东卓; 祝宝东; 王鉴; 张帅; 潘宇亭; 何乾坤

    2014-01-01

    Super absorbent material is a new type of functional polymer material with important application value. This article reviews the pretreatment,the graft modification and the compound modification of natural cellulose in recent years,and also introduces fungi cellulose. Pretreatment methods are emphasized,including alkalization,etherification,ionic liquids dispose and organic solvent dispose,the graft modification of cellulose and cellulose derivatives,and the preparation of super absorbent material by cellulose/silicate complex,cellulose/metal nanoparticles complex and cellulose/highpolymer complex. The cellulose-based super absorbent materials have a wide applied perspective in agriculture,pharmacy and environmental protection.%纤维素基高吸水材料是一种新型的功能高分子材料,具有重要的应用价值。本文综述了近年来天然纤维素的预处理、接枝改性和复合改性,并介绍了菌类纤维素,主要阐述了碱化、醚化、离子液体和有机溶剂对纤维素的预处理,纤维素、纤维素衍生物接枝改性以及纤维素与硅酸盐矿物,金属纳米粒子和高聚物复合制备高吸水材料,指出纤维素基高吸水材料在农业、制药、环保等领域应用前景广阔。

  15. Progress report on the results of testing advanced conceptual design metal barrier materials under relevant environmental conditions for a tuff repository

    Energy Technology Data Exchange (ETDEWEB)

    McCright, R.D.; Halsey, W.G.; Van Konynenburg, R.A.

    1987-12-01

    This report discusses the performance of candidate metallic materials envisioned for fabricating waste package containers for long-term disposal at a possible geological repository at Yucca Mountain, Nevada. Candidate materials include austenitic iron-base to nickel-base alloy (AISI 304L, AISI 316L, and Alloy 825), high-purity copper (CDA 102), and copper-base alloys (CDA 613 and CDA 715). Possible degradation modes affecting these container materials are identified in the context of anticipated environmental conditions at the repository site. Low-temperature oxidation is the dominant degradation mode over most of the time period of concern (minimum of 300 yr to a maximum of 1000 yr after repository closure), but various forms of aqueous corrosion will occur when water infiltrates into the near-package environment. The results of three years of experimental work in different repository-relevant environments are presented. Much of the work was performed in water taken from Well J-13, located near the repository, and some of the experiments included gamma irradiation of the water or vapor environment. The influence of metallurgical effects on the corrosion and oxidation resistance of the material is reviewed; these effects result from container fabrication, welding, and long-term aging at moderately elevated temperatures in the repository. The report indicates the need for mechanisms to understand the physical/chemical reactions that determine the nature and rate of the different degradation modes, and the subsequent need for models based on these mechanisms for projecting the long-term performance of the container from comparatively short-term laboratory data. 91 refs., 17 figs., 16 tabs.

  16. 水滑石类材料在重金属废水治理中的应用进展%PROGRESS IN APPLICATION OF HYDROTALCITE-LIKE MATERIALS IN HEAVY METAL WASTEWATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    朱洪涛; 马玉晶

    2011-01-01

    Hydrotalcite-like materials remove heavy metal from water by four mainly mechanisms: ion exchange, memory effect, chelation and surface adsorption. The application of raw hydrotalcites, calcined hydrotalcites and intercalated hydrotalcite-like materials in heavy metal wastewater treatment and the new progress in its researches were introduced. Various hydrotalcite-like materials, which possessed special properties, could be synthesized by using the mobility of their ionic species and quantities. Therefore the study of these advanced materials would greatly expand the application of hydrotalcite-like materials in adsorption field. Hydrotalcite-like materials have been considered as easy to be synthesized, easy to be separated, cheap and recycled adsorbents and exhibit excellent applied prospect in water treatment.%总结了水滑石类材料对重金属离子吸附机理主要为离子交换作用、记忆效应、螯合作用和表面吸附;重点介绍了国外关于未焙烧水滑石、焙烧态水滑石以及插层水滑石在重金属废水治理中的最新研究应用进展;指出利用构成水滑石层板及插入层间的离子种类和数量的可调控性,可制备一系列具有特殊性能的水滑石类材料,将极大拓宽水滑石材料在吸附领域的应用范围;同时水滑石类材料合成简单、易于分离、成本低廉及可重复利用,显示了其在重金属废水处理中的良好应用前景.

  17. Research progress in cathode materials for rechargeable magnesium battery%可逆镁电池正极材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨雷雷; 李法强; 贾国凤; 彭正军; 朱朝梁; 朱虹

    2012-01-01

    Rechargeable magnesium battery has been considered a potential of 'green power' battery.However.it was hard to found a suitable cathode material for it.The studies and developments of cathode materials of magnesium battery were introduced.Transition metal sulfides, oxides and organic compounds, and a new cathode material of Mg1.03Mn0.97SiO4 etc.were introduced in detail.Furthermore,the current problems as well as corresponding research directions were discussed,and their possible application prospects were also proposed.%可逆镁电池是一种颇具潜力的“绿色动力”电池,寻找合适的正极材料一直是镁电池研究的难点.介绍了可逆镁电池正极材料的研究及发展情况,重点介绍了过渡金属硫化物、氧化物及有机物正极材料.以及新型正极材料MgL03Mn0.97SiO4等,探讨了当前存在的问题及研究的方向,并对其应用前景进行了展望.

  18. 船舶复合材料国外最新进展%The Foreign Latest Progress of Composite Materials for Ships

    Institute of Scientific and Technical Information of China (English)

    司卫华

    2011-01-01

    综述了船舶复合材料的前沿发展,面对增强塑料在船舶制造上的现有限制进行了分析,并提供了针对性的解决建议;介绍了"现代船舶建造中的碳纤维复合材料"领域的PlanetSolar的双体船项目,讨论了复合材料在船舶制造中的应用,作为现代制造业中的先进技术之一的复合材料的软件工具,及其对更多造船厂的视线吸引.同时对今后的发展进行了预测.%In this paper, the development of composite materials for ships was summarized. The limitation of reinforced plastics in shipbuilding was analyzed and the targeted solution proposal was supplied. The PlanetSolar project of catamarans using carbon fiber reinforced plastics (CFRP) in modern shipbuilding was introduced. The application of the composite materials in shipbuilding and the software tools for composite materials as one of the advanced technology in the modern manufacturing, were discussed. The vision attract to more shipyards was also commented. At the same time, the further development was predicted.

  19. RECENT PROGRESS IN STARCH-BASED POLYMERIC MATERIALS%淀粉基高分子材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    汪秀丽; 张玉荣; 王玉忠

    2011-01-01

    Starch,as a natural polymer,has the advantages of renewability,biodegradability, abundance and low cost,and has received great attention in non-food applications for a long time. However, starch cannot be used alone as a polymeric material due to its insolubility in cold water, poor shearing stability and water resistance ,and absence of melting flow. Therefore, it should be chemically/physically modified in order to strengthen some functions or form some new properties. This review provides an insight into some developments in the chemical and physical modification of starch for its applications in biodegradable plastics, absorption materials, tissue engineering scaffold and drug carriers primarily based on the publications that appeared during the last five years. The chemical modification of starch included esterification, etherification, oxidation,crosslinking and graft polymerization. The physical modification of starch focused on the blending of starch with other biodegradable polymers such as aliphatic polyesters, poly(vinyl alcohol ) and other natural macromolecules. Starch nanocrystals obtained by acid hydrolysis were also reviewed, and they can be functionalized or used to enhance the mechanical properties of starch or other polymer materials. As a kind of renewable material, starch, especially the non-food starch should receive more and more attentions in the preparation of practical polymeric materials in the future.%概述了近5年国内外在淀粉的化学、物理改性及其作为一种材料使用方面取得的最新研究进展.淀粉的化学改性主要介绍了淀粉的酯化、醚化、氧化、交联、接枝共聚等,而物理改性主要介绍了淀粉分别与黏土、脂肪族聚酯、聚乙烯醇以及纤维素等天然大分子的共混改性,同时还介绍了通过酸化制备淀粉纳米晶.淀粉基材料除了用于制备可生物降解塑料、吸附材料等传统领域外,近年来还被用于组织工程支架、药物释放载体等生物医用领域.

  20. Study Progress on Pharmacodynamic Material Basis of Chinese Materia Medica%中药药效物质基础研究进展

    Institute of Scientific and Technical Information of China (English)

    郭倩; 田成旺; 任涛; 张铁军

    2015-01-01

    Study on pharmacodynamic material basis of Chinese materia medica (CMM) is one of the key points of CMM modern research. It is also the core of ascertaining the overall efficacy and the function essence of CMM. It is an important basis for the safety, efficacy and quality control of CMM. However, since the multiple components, complex medical effects and interactions among effective components of CMM, the clarification of pharmacodynamic material basis has become a difficult question, which restricts the CMM modernization. Therefore, pharmacodynamic material basis of CMM has received widespread attention in the academic field. Many experts and scholars have done a lot of research and practice on this area. This article analyzed relevant literatures about pharmacodynamic material basis researches of CMM, and reviewed connotation, research thoughts and methods of CMM. It discussed some existing problems in current studies. The goal was to provide references for pharmacodynamic material basis of CMM.%中药药效物质基础研究是中药现代研究的关键点之一,是阐释中药整体功效及其作用本质的核心环节,是中药安全、有效和质量控制的重要基础.但由于中药多成分和药效作用的复杂性,以及中药各有效成分的协同作用,使得中药药效物质基础的阐明成为难题,制约着中医药的现代化进程.因此,中药药效物质基础目前已受到学术界的广泛重视,许多专家学者对此进行了大量的研究和实践.本文通过回顾、分析近年来中药药效物质基础研究的相关文献,综述了中药药效物质基础的内涵、研究思路和方法,并探讨了目前研究中存在的一些问题,以期对中药药效物质基础研究提供参考.