WorldWideScience

Sample records for gasb based vertical-resonator

  1. The material system (AlGaIn)(AsSb). Properties and suitability for GaSb based vertical-resonator laser diodes

    Dier, Oliver

    2008-01-01

    The present thesis studies the particular properties of GaSb-based materials, where they differ from pure arsenides or phosphides, and also the impact of theses properties on long-wavelength vertical-cavity surface-emitting lasers (VCSELs). The goal is the first realisation of an electrically pumped VCSEL with a current aperture in this material system. After the basics, which are necessary for the understanding of the physical effects, the special features of antimony-containing materials are discussed with a focus on topics like band-structure, doping issues and miscibility gaps, which are relevant for devices. A VCSEL-structure optimized for long-wavelength applications is presented using an appropriate description of the device in its optical, electrical and thermal properties. A focus of this work is on the growth of laser-structures by molecular beam epitaxy. Annealing studies on this material showed a good prediction of the final wavelength after the temperature step, which is necessary due to the overgrowth of the tunnel-junction. The full-width at half maximum of the low-temperature photoluminescence signal shows a very low value of 3.95 meV for the quaternary active region. By using the type-II-band alignment of GaSb:Si and InAsSb:Si a low-resistive tunneljunction has been realised. After completion of the device processing a strong electroluminescence outside the DBR stopband and resonant modes within the stopband were found. A linear shift of the emission wavelength with temperature of 0.23 nm/K between -11 C and +30 C was found. (orig.)

  2. The material system (AlGaIn)(AsSb). Properties and suitability for GaSb based vertical-resonator laser diodes; Das Materialsystem (AlGaIn)(AsSb). Eigenschaften und Eignung fuer GaSb-basierte Vertikalresonator-Laserdioden

    Dier, Oliver

    2008-07-01

    The present thesis studies the particular properties of GaSb-based materials, where they differ from pure arsenides or phosphides, and also the impact of theses properties on long-wavelength vertical-cavity surface-emitting lasers (VCSELs). The goal is the first realisation of an electrically pumped VCSEL with a current aperture in this material system. After the basics, which are necessary for the understanding of the physical effects, the special features of antimony-containing materials are discussed with a focus on topics like band-structure, doping issues and miscibility gaps, which are relevant for devices. A VCSEL-structure optimized for long-wavelength applications is presented using an appropriate description of the device in its optical, electrical and thermal properties. A focus of this work is on the growth of laser-structures by molecular beam epitaxy. Annealing studies on this material showed a good prediction of the final wavelength after the temperature step, which is necessary due to the overgrowth of the tunnel-junction. The full-width at half maximum of the low-temperature photoluminescence signal shows a very low value of 3.95 meV for the quaternary active region. By using the type-II-band alignment of GaSb:Si and InAsSb:Si a low-resistive tunneljunction has been realised. After completion of the device processing a strong electroluminescence outside the DBR stopband and resonant modes within the stopband were found. A linear shift of the emission wavelength with temperature of 0.23 nm/K between -11 C and +30 C was found. (orig.)

  3. Diagnostic and characterization of the VCSEL diodes based on GaSb

    Matulková, Irena; Cihelka, Jaroslav; Vyskočil, Jan; Zelinger, Zdeněk; Hulicius, Eduard; Šimeček, Tomislav; Civiš, Svatopluk

    2010-01-01

    Roč. 99, 1-2 (2010), s. 333-338 ISSN 0946-2171 R&D Projects: GA AV ČR IAA400400705 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100521 Keywords : VCSEL diode s * FTIR * GaSb Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.239, year: 2010

  4. Next generation DIRCM for 2.1-2.3 micron wavelength based on direct-diode GaSb technology

    Dvinelis, Edgaras; Naujokaitė, Greta; Greibus, Mindaugas; Trinkūnas, Augustinas; Vizbaras, Kristijonas; Vizbaras, Augustinas

    2018-02-01

    Continuous advances in low-cost MANPAD heat-seeking missile technology over the past 50 years remains the number one hostile threat to airborne platforms globally responsible for over 60 % of casualties. Laser based directional countermeasure (DIRCM) technology have been deployed to counter the threat. Ideally, a laser based DIRCM system must involve a number of lasers emitting at different spectral bands mimicking the spectral signature of the airborne platform. Up to now, near and mid infrared spectral bands have been covered with semiconductor laser technology and only SWIR band remained with bulky fiber laser technology. Recent technology developments on direct-diode GaSb laser technology at Brolis Semiconductors offer a replacement for the fiber laser source leading to significant improvements by few orders of magnitude in weight, footprint, efficiency and cost. We demonstrate that with careful engineering, several multimode emitters can be combined to provide a directional laser beam with radiant intensity from 10 kW/sr to 60 kW/sr in an ultra-compact hermetic package with weight < 30 g and overall efficiency of 15 % in the 2.1- 2.3 micron spectral band offering 150 times improvement in efficiency and reduction in footprint. We will discuss present results, challenges and future developments for such next-generation integrated direct diode DIRCM modules for SWIR band.

  5. Noise spectroscopy measurement of 2.3μm CW GaSb based laser diodes

    Chobola, Z.; Juránková, V.; Vaněk, J.; Hulicius, Eduard; Šimeček, Tomislav; Alibert, C.; Rouillard, Y.; Werner, R.

    2005-01-01

    Roč. 1, - (2005), s. 70-73 ISSN 0033-2089 R&D Projects: GA MŠk(CZ) LC510; GA AV ČR(CZ) KSK1010104 Grant - others:EC Project GLADIS(XE) IST-2001-35178 Institutional research plan: CEZ:AV0Z1010914 Keywords : noise spectroscopy * GaSb * laser diode * 1/f noise Subject RIV: BM - Solid Matter Physics ; Magnetism

  6. Indium gallium zinc oxide (IGZO)-based Ohmic contact formation on n-type gallium antimony (GaSb)

    Shin, Jeong-Hun; Jung, Hyun-Wook [Samsung-SKKU Graphene Center and School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Jung, Woo-Shik [Department of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States); Park, Jin-Hong, E-mail: jhpark9@skku.edu [Samsung-SKKU Graphene Center and School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-02-14

    In this paper, Ohmic-like contact on n-type GaSb with on/off-current ratio of 1.64 is presented, which is formed at 500 °C by inserting IGZO between metal (Ni) and GaSb. The resulting Ohmic contact is systematically investigated by TOF-SIMS, HSC chemistry simulation, XPS, TEM, AFM, and J–V measurements. Two main factors contributing to the Ohmic contact formation are (1) InSb (or InGaSb) with narrow energy bandgap (providing low electron and hole barrier heights) formed by In diffusion from IGZO and Sb released by Ga oxidation, and (2) free Sb working as traps that induces tunneling current. - Highlights: • We demonstrate Ohmic-like contact on n-type GaSb with on/off-current ratio of 1.64. • The reverse current is increased by low electron barrier height and high TAT current. • The low electron barrier height is achieved by the formation of InGaSb. • Free Sb atoms also work as traps inducing high TAT current.

  7. Tips for School Districts: GASB's New Fund Balance Standards

    Mead, Dean Michael

    2010-01-01

    In March 2009, the Governmental Accounting Standards Board (GASB) issued Statement No. 54, "Fund Balance Reporting and Governmental Fund Type Definitions." School districts that prepare financial reports based on generally accepted accounting principles are required to implement this standard no later than the first fiscal year that starts after…

  8. Assessing Risk with GASB Statement No. 3.

    Wood, Venita M.; Scott, Bob

    1987-01-01

    Discusses a Government Accounting Standards Board (GASB) publication designed to provide financial statement users with information to assess a government's actual and future deposit and investment market and credit risk. (MLF)

  9. Spectral responses in near-infrared of the mixed compounds III-V ternary and quaternary, based on GaSb

    Mbow, B.; Rezzoug, N.; Peremarti, C.; Mezerreg, A.; Llinares, C.

    1993-09-01

    From the simulation of the spectral response of the different photodetector devices elaborated in our laboratory (C.E.M.), we determine the influence of geometrical and physical parameters in order to achieve the best photodetector operating at the wavelength 2.55 μm. In this paper we present: Gao{0.6}In{0.4}Sbn/Ga{0.6}In{0.4}Sbp homojunctions matched on GaSbp substrate, Ga{0.75}In{0.25}As{0.23}Sbp/GaSbn ternary heterojunction and GaSbp/Ga{0.74}In{0.26}As{0.23}Sb0.77p/GaSbn quaternary heterojunction. The GaSbp layer with an energy band gap greater than Ga{0.74}In{0.26}As{0.23}Sb0.77p optical gap will act as a window, reducing the effect of surface recombinaison. Results of the simulation are compared to experimental curves to determine the values of photoelectrical parameters (diffusion length, recombination velocity at the surface ...). Les mesures de réponse spectrale dans la gamme [0,4 eV à 2 eV] ont été effectuées sur des homojonctions, Ga{0,6}In{0,4}Sbn/Ga{0,6}In{0,4}Sbp déposées sur un substrat de GaSb et des hétérostructures ternaires Ga{0,75}In{0,25}Sbp/GaSbn et quaternaires GaSbp/Ga{0,74}In{0,26}As{0,23}Sb0,77p/GaSbn. La couche de GaSbp avec un gap plus grand que celui de Ga{0,74}In{0,26}As{0,23}Sb0,77p joue le rôle d'effet fenêtre. En s'appuyant sur les résultats de la simulation et en accordant les spectres expérimentaux aux spectres théoriques, on détermine les valeurs des paramètres photoélectriques (longueurs de diffusion, les vitesses de recombinaison en surface ... ) intervenant dans le rendement quantique.

  10. Two-band superlinear electroluminescence in GaSb based nanoheterostructures with AlSb/InAs.sub.1-x./sub.Sb.sub.x./sub./AlSb deep quantum well

    Mikhailova, M. P.; Ivanov, E.V.; Danilov, L.V.; Petukhov, A.A.; Kalinina, K.V.; Slobozhanyuk, S.I.; Zegrya, G.G.; Stoyanov, N. D.; Yakovlev, Yu. P.; Hospodková, Alice; Pangrác, Jiří; Oswald, Jiří; Zíková, Markéta; Hulicius, Eduard

    2014-01-01

    Roč. 115, č. 22 (2014), "223102-1"-"223102-5" ISSN 0021-8979 R&D Projects: GA ČR GA13-15286S Institutional support: RVO:68378271 Keywords : MOVPE * GaSb * InAs * electroluminescence * quantum well Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2014

  11. GASB 35 Implementation Guide: Questions and Answers for Public Colleges and Universities Using Business Type Activity (BTA) Reporting. A Supplement to GASB's Implementation Guide for Statement 34

    National Association of College and University Business Officers (NJ1), 2001

    2001-01-01

    This guide was prepared for public institution business officers as a supplement to the "Guide to Implementation of GASB Statement 54 on Basic Financial Statements--and Management's Discussion and Analysis--for State and Local Governments, published in April 2000 by the Governmental Accounting Standards Board (GASB) on GASB Statements 34 and 35.…

  12. GASB 35: The New Financial Reporting Requirements for Public College and Universities.

    Qayoumi, Mohammad H.

    2001-01-01

    Presents the basic financial reporting elements of the Governmental Accounting Standards Board (GASB-35) for public colleges and universities, including statements of net assets and cash flow reporting. The GASB-35's impact on facilities managers is discussed. (GR)

  13. Epitaxial growth of GaSb on V-grooved Si (001) substrates with an ultrathin GaAs stress relaxing layer

    Li, Qiang; Lai, Billy; Lau, Kei May

    2017-10-01

    We report epitaxial growth of GaSb nano-ridge structures and planar thin films on V-groove patterned Si (001) substrates by leveraging the aspect ratio trapping technique. GaSb was deposited on {111} Si facets of the V-shaped trenches using metal-organic chemical vapor deposition with a 7 nm GaAs growth initiation layer. Transmission electron microscopy analysis reveals the critical role of the GaAs layer in providing a U-shaped surface for subsequent GaSb epitaxy. A network of misfit dislocations was uncovered at the GaSb/GaAs hetero-interface. We studied the evolution of the lattice relaxation as the growth progresses from closely pitched GaSb ridges to coalesced thin films using x-ray diffraction. The omega rocking curve full-width-at-half-maximum of the resultant GaSb thin film is among the lowest values reported by molecular beam epitaxy, substantiating the effectiveness of the defect necking mechanism. These results thus present promising opportunities for the heterogeneous integration of devices based on 6.1 Å family compound semiconductors.

  14. Point defect balance in epitaxial GaSb

    Segercrantz, N.; Slotte, J.; Makkonen, I.; Kujala, J.; Tuomisto, F.; Song, Y.; Wang, S.

    2014-01-01

    Positron annihilation spectroscopy in both conventional and coincidence Doppler broadening mode is used for studying the effect of growth conditions on the point defect balance in GaSb:Bi epitaxial layers grown by molecular beam epitaxy. Positron annihilation characteristics in GaSb are also calculated using density functional theory and compared to experimental results. We conclude that while the main positron trapping defect in bulk samples is the Ga antisite, the Ga vacancy is the most prominent trap in the samples grown by molecular beam epitaxy. The results suggest that the p–type conductivity is caused by different defects in GaSb grown with different methods.

  15. Cathodoluminescence study of ytterbium doped GaSb

    Hidalgo, P.; Mendez, B.; Ruiz, C.; Bermudez, V.; Piqueras, J.; Dieguez, E.

    2005-01-01

    Yb-doped GaSb ingots have been grown by the Bridgman method. The defect structure and compositional homogeneity of the crystals have been investigated by cathodoluminescence and X-ray microanalysis in the scanning electron microscope. The nature of the point defects has been found to depend on the position along the growth axis. Doping with Yb has been found to reduce the luminescence intensity of GaSb and no infrared emission related to intra-ionic transitions of the Yb 3+ ions has been detected

  16. Optical and structural characterization of GaSb and Te-doped GaSb single crystals

    Tirado-Mejia, L.; Villada, J.A.; Rios, M. de los; Penafiel, J.A.; Fonthal, G.; Espinosa-Arbelaez, D.G.; Ariza-Calderon, H.; Rodriguez-Garcia, M.E.

    2008-01-01

    Optical and structural properties of GaSb and Te-doped GaSb single crystals are reported herein. Utilizing the photoreflectance technique, the band gap energy for doped samples was obtained at 0.814 eV. Photoluminescence (PL) spectra showed a peak at 0.748 eV that according to this research, belongs to electronic states of pure GaSb and not to the longitudinal optical (LO) phonon replica as has been reported by other authors. Analysis of the full width at half maximum (FWHM) values of X-ray diffraction, as well as micro-Raman peaks showed that the inclusion of Te decreases the crystalline quality

  17. Unusual crystallization behavior in Ga-Sb phase change alloys

    Magali Putero

    2013-12-01

    Full Text Available Combined in situ X-ray scattering techniques using synchrotron radiation were applied to investigate the crystallization behavior of Sb-rich Ga-Sb alloys. Measurements of the sheet resistance during heating indicated a reduced crystallization temperature with increased Sb content, which was confirmed by in situ X-ray diffraction. The electrical contrast increased with increasing Sb content and the resistivities in both the amorphous and crystalline phases decreased. It was found that by tuning the composition between Ga:Sb = 9:91 (in at.% and Ga:Sb = 45:55, the change in mass density upon crystallization changes from an increase in mass density which is typical for most phase change materials to a decrease in mass density. At the composition of Ga:Sb = 30:70, no mass density change is observed which should be very beneficial for phase change random access memory (PCRAM applications where a change in mass density during cycling is assumed to cause void formation and PCRAM device failure.

  18. GASB's New Financial Reporting Model: Implementation Project for School Districts.

    Bean, David; Glick, Paul

    1999-01-01

    In June 1999, the Governmental Accounting Standards Board (GASB) issued its statement on the structure of the basic financial reporting model for state and local governments. Explains the new financial reporting model and reviews the implementation issues that school districts will need to address. (MLF)

  19. The electronic structures and ferromagnetism of Fe-doped GaSb: The first-principle calculation study

    Lin, Xue-ling; Niu, Cao-ping; Pan, Feng-chun; Chen, Huan-ming; Wang, Xu-ming

    2017-09-01

    The electronic structures and the magnetic properties of Fe doped GaSb have been investigated by the first-principles calculation based on the framework of the generalized gradient approximation (GGA) and GGA+U schemes. The calculated results indicated that Fe atoms tend to form the anti-ferromagnetic (AFM) coupling with the nearest-neighbor positions preferentially. Compared with the anti-ferromagnetic coupling, the ferromagnetic interactions occurred at the second nearest-neighbor and third nearest-neighbor sites have a bigger superiority energetically. The effect of strong electron correlation at Fe-d orbit taking on the magnetic properties predicted by GGA+U approach demonstrated that the ferromagnetic (FM) coupling between the Fe ions is even stronger in consideration of the strong electron correlation effect. The ferromagnetism in Fe doped GaSb system predicted by our investigation implied that the doping of Fe into GaSb can be as a vital routine for manufacturing the FM semiconductors with higher Curie temperature.

  20. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    Laura B. Ruppalt

    2014-12-01

    Full Text Available In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD high-k dielectric stacks with device-quality p-type GaSb(001 epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H2/Ar plasma treatment and subsequently removed to air. High-k HfO2 and Al2O3/HfO2 bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H2-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H2-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  1. Approaching the Hole Mobility Limit of GaSb Nanowires.

    Yang, Zai-xing; Yip, SenPo; Li, Dapan; Han, Ning; Dong, Guofa; Liang, Xiaoguang; Shu, Lei; Hung, Tak Fu; Mo, Xiaoliang; Ho, Johnny C

    2015-09-22

    In recent years, high-mobility GaSb nanowires have received tremendous attention for high-performance p-type transistors; however, due to the difficulty in achieving thin and uniform nanowires (NWs), there is limited report until now addressing their diameter-dependent properties and their hole mobility limit in this important one-dimensional material system, where all these are essential information for the deployment of GaSb NWs in various applications. Here, by employing the newly developed surfactant-assisted chemical vapor deposition, high-quality and uniform GaSb NWs with controllable diameters, spanning from 16 to 70 nm, are successfully prepared, enabling the direct assessment of their growth orientation and hole mobility as a function of diameter while elucidating the role of sulfur surfactant and the interplay between surface and interface energies of NWs on their electrical properties. The sulfur passivation is found to efficiently stabilize the high-energy NW sidewalls of (111) and (311) in order to yield the thin NWs (i.e., 40 nm in diameters) would grow along the most energy-favorable close-packed planes with the orientation of ⟨111⟩, supported by the approximate atomic models. Importantly, through the reliable control of sulfur passivation, growth orientation and surface roughness, GaSb NWs with the peak hole mobility of ∼400 cm(2)V s(-1) for the diameter of 48 nm, approaching the theoretical limit under the hole concentration of ∼2.2 × 10(18) cm(-3), can be achieved for the first time. All these indicate their promising potency for utilizations in different technological domains.

  2. Biocompatibility of GaSb thin films grown by RF magnetron sputtering

    Nishimoto, Naoki; Fujihara, Junko; Yoshino, Katsumi

    2017-07-01

    GaSb may be suitable for biological applications, such as cellular sensors and bio-medical instrumentation because of its low toxicity compared with As (III) compounds and its band gap energy. Therefore, the biocompatibility and the film properties under physiological conditions were investigated for GaSb thin films with or without a surface coating. GaSb thin films were grown on quartz substrates by RF magnetron sputtering, and then coated with (3-mercaptopropyl) trimethoxysilane (MPT). The electrical properties, surface morphology, and crystal structure of the GaSb thin film were unaffected by the MPT coating. The cell viability assay suggested that MPT-coated GaSb thin films are biocompatible. Bare GaSb was particularly unstable in pH9 buffer. Ga elution was prevented by the MPT coating, although the Ga concentration in the pH 9 buffer was higher than that in the other solutions. The surface morphology and crystal structure were not changed by exposure to the solutions, except for the pH 9 buffer, and the thin film properties of MPT-coated GaSb exposed to distilled water and H2O2 in saline were maintained. These results indicate that MPT-coated GaSb thin films are biocompatible and could be used for temporary biomedical devices.

  3. Bismuth-induced restructuring of the GaSb(110) surface

    Gemmeren, T. van; Lottermoser, L.; Falkenberg, G.

    1998-01-01

    The structure of the GaSb(110)(1 x 2)-Bi reconstruction has been solved using surface x-ray diffraction, scanning tunneling microscopy, and photoelectron spectroscopy. The ideal GaSb(110) surface is terminated with zigzag chains of anions and cations running in the [1 (1) over bar 0] direction...

  4. GaSb solar cells grown on GaAs via interfacial misfit arrays for use in the III-Sb multi-junction cell

    Nelson, George T.; Juang, Bor-Chau; Slocum, Michael A.; Bittner, Zachary S.; Laghumavarapu, Ramesh B.; Huffaker, Diana L.; Hubbard, Seth M.

    2017-12-01

    Growth of GaSb with low threading dislocation density directly on GaAs may be possible with the strategic strain relaxation of interfacial misfit arrays. This creates an opportunity for a multi-junction solar cell with access to a wide range of well-developed direct bandgap materials. Multi-junction cells with a single layer of GaSb/GaAs interfacial misfit arrays could achieve higher efficiency than state-of-the-art inverted metamorphic multi-junction cells while forgoing the need for costly compositionally graded buffer layers. To develop this technology, GaSb single junction cells were grown via molecular beam epitaxy on both GaSb and GaAs substrates to compare homoepitaxial and heteroepitaxial GaSb device results. The GaSb-on-GaSb cell had an AM1.5g efficiency of 5.5% and a 44-sun AM1.5d efficiency of 8.9%. The GaSb-on-GaAs cell was 1.0% efficient under AM1.5g and 4.5% at 44 suns. The lower performance of the heteroepitaxial cell was due to low minority carrier Shockley-Read-Hall lifetimes and bulk shunting caused by defects related to the mismatched growth. A physics-based device simulator was used to create an inverted triple-junction GaInP/GaAs/GaSb model. The model predicted that, with current GaSb-on-GaAs material quality, the not-current-matched, proof-of-concept cell would provide 0.5% absolute efficiency gain over a tandem GaInP/GaAs cell at 1 sun and 2.5% gain at 44 suns, indicating that the effectiveness of the GaSb junction was a function of concentration.

  5. Consistency endangered by FASB-GASB (Financial Accounting Standards Board, Government Accounting Standards Board ) dispute.

    Garner, M; Grossman, W

    1991-02-01

    The Financial Accounting Foundation's (FAF's) November 1989 decision to uphold the 1984 jurisdictional arrangement between the Financial Accounting Standards Board (FASB) and the Government Accounting Standards Board (GASB) leaves little doubt that the healthcare industry will now be subject to two sets of accounting standards. The FAF's decision created a distinction between the accounting practices of government-owned hospitals and non-hospital governmental entities and their adherence to standards set by FASB, GASB, and the American Institute of Certified Public Accountants. A governmental healthcare organization should carefully determine which accounting rules it follows and remain attentive to further GASB developments.

  6. Performance evaluation of thermophotovoltaic GaSb cell technology in high temperature waste heat

    Utlu, Z.; Önal, B. S.

    2018-02-01

    In this study, waste heat was evaluated and examined by means of thermophotovoltaic systems with the application of energy production potential GaSb cells. The aim of our study is to examine GaSb cell technology at high temperature waste heat. The evaluation of the waste heat to be used in the system is designed to be used in the electricity, industry and iron and steel industry. Our work is research. Graphic analysis is done with Matlab program. The high temperature waste heat graphs applied on the GaSb cell are in the results section. Our study aims to provide a source for future studies.

  7. Examination of thermophotovoltaic GaSb cell technology in low and medium temperatures waste heat

    Utlu, Z.; Önal, B. S.

    2018-02-01

    In this study, waste heat was evaluated and examined by means of thermophotovoltaic systems with the application of energy production potential GaSb cells. The aim of our study is to examine GaSb cell technology at low and medium temperature waste heat. The evaluation of the waste heat to be used in the system is designed to be used in the electricity, industry and iron and steel industry. Our work is research. Graphic analysis is done with Matlab program. The low and medium temperature waste heat graphs applied on the GaSb cell are in the results section. Our study aims to provide a source for future studies.

  8. Optical properties of GaSb(001)-c(2 x 6): The role of surface antisite defects

    Hogan, Conor; Del Sole, Rodolfo [Department of Physics, CNR-INFM-SMC, Roma (Italy); European Theoretical Spectroscopy Facility (ETSF), University of Rome ' ' Tor Vergata' ' , Roma (Italy); Magri, Rita [Centro S3-CNR-Istituto di Nanoscienze, Modena (Italy); Department of Physics, University of Modena and Reggio Emilia, Modena (Italy)

    2010-08-15

    We consider the formation of surface antisite defects on a previously proposed model for the GaSb(001)-c(2 x 6) surface. Based on ab initio total energy calculations, we show how these defects stabilize the otherwise metallic surface and how their formation is driven by the excess charge associated with the Sb-rich surface conditions. The surface-sensitive optical technique of reflectance anisotropy spectroscopy is shown to be crucial for detecting the defects, and computation of spectra yields a good agreement with experiment when defects are included in the surface reconstruction. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. 75 FR 33306 - Notice of Meeting Location Change and Joint Meeting of FASAB and GASB

    2010-06-11

    ... meeting is to discuss: --Measurement Attributes, --Reporting Model, --Cost Accounting, and --Governance... FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Meeting Location Change and Joint Meeting of FASAB and GASB AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board Action...

  10. Origin of the reverse optical-contrast change of Ga-Sb phase-change materials—An ab initio molecular-dynamics study

    Dixon, J. A.; Elliott, S. R., E-mail: sre1@cam.ac.uk [Department of Chemistry, University of Cambridge, Cambridge CB2 1EW (United Kingdom)

    2014-04-07

    A large number of phase-change materials (PCMs) have been developed experimentally; however, only Ge{sub 2}Sb{sub 2}Te{sub 5}-based PCMs have been significantly explored using ab initio molecular-dynamics (AIMD) simulations. We present an AIMD study of the full melt/quench/anneal PC cycle for Ga-Sb materials, namely, the stoichiometric composition, GaSb, and the near-eutectic alloy, Ga{sub 16}Sb{sub 84}. The calculated electronic densities of states and optical reflectivities are compared between the amorphous and crystalline phases for both compositions, and it is shown that the contrasting opto-electronic properties of each crystalline material can be attributed to different structural transformations of Ga and Sb on crystallization from the amorphous state.

  11. Growth of GaSb1-xBix by molecular beam epitaxy

    Song, Yuxin; Wang, Shumin; Roy, Ivy Saha

    2012-01-01

    Molecular beam epitaxy for GaSb1-xBix is investigated in this article. The growth window for incorporation of Bi in GaSb was found. Strategies of avoiding formation of Bi droplets and enhancing Bi incorporation were studied. The Bi incorporation was confirmed by SIMS and RBS measurements. The Bi ......As substrates were compared and no apparent difference for Bi incorporation was found.......Molecular beam epitaxy for GaSb1-xBix is investigated in this article. The growth window for incorporation of Bi in GaSb was found. Strategies of avoiding formation of Bi droplets and enhancing Bi incorporation were studied. The Bi incorporation was confirmed by SIMS and RBS measurements. The Bi...... concentration in the samples was found to increase with increasing growth temperature and Bi flux. The position of GaSb1-xBix layer peak in XRD rocking curves is found to be correlated to Bi composition. Surface and structural properties of the samples were also investigated. Samples grown on GaSb and Ga...

  12. Residual carrier density in GaSb grown on Si substrates

    Akahane, Kouichi; Yamamoto, Naokatsu; Gozu, Shin-ichiro; Ueta, Akio; Ohtani, Naoki

    2006-01-01

    The relationships between the densities of residual carriers and those of dislocation in GaSb films grown on Si substrates were investigated. Dislocation density was evaluated by cross-sectional transmission electron microscopy (TEM). The TEM images indicated that the dislocation density after a 5-μm-thick GaSb film was grown was below 1 x 10 8 /cm 2 although the density near the interface between the Si substrate and the GaSb film was about 3 x 10 9 /cm 2 . Forming a dislocation loop by growing a thick GaSb layer may decrease the dislocation density. The density and mobility of the residual carrier were investigated by Hall measurement using the van der Pauw method. The residual carriers in GaSb grown on Si substrates were holes, and their densities decreased significantly from 4.2 x 10 18 to 1.4 x 10 17 /cm 3 as GaSb thickness was increased from 500 to 5500 nm

  13. Formation Mechanism of Self Assembled Horizontal ErSb Nanowires Embedded in a GaSb(001) Matrix

    Wilson, Nathaniel; Kraemer, Stephan; PalmstrøM, Chris

    The ErxGa1-xSb exhibits a variety of self-assembling nanostructures. In order to harness these nanostructures for use in devices and other material systems it is important to understand their formation. We have characterized the growth mechanism of self-assembled horizontal ErSb nanowires in a GaSb(001) matrix through the use of in-situ Scanning Tunneling Microscopy (STM) as well as ex-situ Transmission Electron Microscopy (TEM). We observe large GaSb macrosteps on the growth surface of Er.3Ga.7Sb samples. The areas near the ledge and base of the macrosteps show significant differences in size and distribution of ErSb nanowires. Results suggest that the formation of macrosteps drives the transition from vertical to horizontal nanowires in the ErxGa1-xSb system. We also observe a low temperature growth mode, which results in horizontal nanowire formation under a wide range of flux conditions. This new growth mode does not exhibit the embedded growth observed in the formation of nanowires at higher temperatures and may allow for horizontal nanowire formation without the presence of macrosteps, as well as the formation of smaller nanoparticles which may be useful for achieving smaller nanoparticle dimensions and electron confinement effects. This work was supported by NSF-DMR under 1507875.

  14. Molecular beam epitaxial growth and characterization of GaSb layers on GaAs (0 0 1) substrates

    Li Yanbo; Zhang Yang; Zhang Yuwei; Wang Baoqiang; Zhu Zhanping; Zeng Yiping

    2012-01-01

    We report on the growth of GaSb layers on GaAs (0 0 1) substrates by molecular beam epitaxy (MBE). We investigate the influence of the GaAs substrate surface treatment, growth temperature, and V/III flux ratios on the crystal quality and the surface morphology of GaSb epilayers. Comparing to Ga-rich GaAs surface preparation, the Sb-rich GaAs surface preparation can promote the growth of higher-quality GaSb material. It is found that the crystal quality, electrical properties, and surface morphology of the GaSb epilayers are highly dependent on the growth temperature, and Sb/Ga flux ratios. Under the optimized growth conditions, we demonstrate the epitaxial growth of high quality GaSb layers on GaAs substrates. The p-type nature of the unintentionally doped GaSb is studied and from the growth conditions dependence of the hole concentrations of the GaSb, we deduce that the main native acceptor in the GaSb is the Ga antisite (Ga Sb ) defect.

  15. Low temperature Zn diffusion for GaSb solar cell structures fabrication

    Sulima, Oleg V.; Faleev, Nikolai N.; Kazantsev, Andrej B.; Mintairov, Alexander M.; Namazov, Ali

    1995-01-01

    Low temperature Zn diffusion in GaSb, where the minimum temperature was 450 C, was studied. The pseudo-closed box (PCB) method was used for Zn diffusion into GaAs, AlGaAs, InP, InGaAs and InGaAsP. The PCB method avoids the inconvenience of sealed ampoules and proved to be simple and reproducible. The special design of the boat for Zn diffusion ensured the uniformality of Zn vapor pressure across the wafer surface, and thus the uniformity of the p-GaSb layer depth. The p-GaSb layers were studied using Raman scattering spectroscopy and the x-ray rocking curve method. As for the postdiffusion processing, an anodic oxidation was used for a precise thinning of the diffused GaSb layers. The results show the applicability of the PCB method for the large-scale production of the GaSb structures for solar cells.

  16. The formation mechanisms and optical characteristics of GaSb quantum rings

    Lin, Wei-Hsun; Pao, Chun-Wei; Wang, Kai-Wei; Liao, Yu-An; Lin, Shih-Yen

    2013-01-01

    The growth mechanisms and optical characteristics of GaSb quantum rings (QRs) are investigated. Although As-for-Sb exchange is the mechanism responsible for the dot-to-ring transition, significant height difference between GaSb quantum dots (QDs) and QRs in a dot/ring mixture sample suggests that the dot-to-ring transition is not a spontaneous procedure. Instead, it is a rapid transition procedure as long as it initiates. A model is established to explain this phenomenon. Larger ring inner diameters and heights of the sample with longer post Sb soaking time suggest that As-for-Sb exchange takes places in both vertical and lateral directions. The decreasing ring densities, enlarged ring inner/outer diameters and eventually flat GaSb surfaces observed with increasing growth temperatures are resulted from enhanced adatom migration and As-for-Sb exchange with increasing growth temperatures

  17. Structural Characterization of Doped GaSb Single Crystals by X-ray Topography

    Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.

    2009-09-13

    We characterized GaSb single crystals containing different dopants (Al, Cd and Te), grown by the Czochralski method, by x-ray topography and high angular resolution x-ray diffraction. Lang topography revealed dislocations parallel and perpendicular to the crystal's surface. Double-crystal GaSb 333 x-ray topography shows dislocations and vertical stripes than can be associated with circular growth bands. We compared our high-angular resolution x-ray diffraction measurements (rocking curves) with the findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter ({Delta}d/d) on the order of 10{sup -5}. This means that they can be used as electronic devices (detectors, for example) and as x-ray monochromators.

  18. The effects of electron and proton radiation on GaSb infrared solar cells

    Gruenbaum, P. E.; Avery, J. E.; Fraas, L. M.

    1991-01-01

    Gallium antimonide (GaSb) infrared solar cells were exposed to 1 MeV electrons and protons up to fluences of 1 times 10(exp 15) cm (-2) and 1 times 10(exp 12) cm (-2) respectively. In between exposures, current voltage and spectral response curves were taken. The GaSb cells were found to degrade slightly less than typical GaAs cells under electron irradiation, and calculations from spectral response curves showed that the damage coefficient for the minority carrier diffusion length was 3.5 times 10(exp 8). The cells degraded faster than GaAs cells under proton irradiation. However, researchers expect the top cell and coverglass to protect the GaSb cell from most damaging protons. Some annealing of proton damage was observed at low temperatures (80 to 160 C).

  19. Short-wave infrared barriode detectors using InGaAsSb absorption material lattice matched to GaSb

    Craig, A. P.; Percy, B.; Marshall, A. R. J. [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Jain, M. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Wicks, G.; Hossain, K. [Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); Golding, T. [Amethyst Research Ltd., Kelvin Campus, West of Scotland Science Park, Glasgow G20 0SP (United Kingdom); Amethyst Research, Inc., 123 Case Circle, Ardmore, Oklahoma 73401 (United States); McEwan, K.; Howle, C. [Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ (United Kingdom)

    2015-05-18

    Short-wave infrared barriode detectors were grown by molecular beam epitaxy. An absorption layer composition of In{sub 0.28}Ga{sub 0.72}As{sub 0.25}Sb{sub 0.75} allowed for lattice matching to GaSb and cut-off wavelengths of 2.9 μm at 250 K and 3.0 μm at room temperature. Arrhenius plots of the dark current density showed diffusion limited dark currents approaching those expected for optimized HgCdTe-based detectors. Specific detectivity figures of around 7×10{sup 10} Jones and 1×10{sup 10} Jones were calculated, for 240 K and room temperature, respectively. Significantly, these devices could support focal plane arrays working at higher operating temperatures.

  20. Compositional and structural characterisation of GaSb and GaInSb

    Corregidor, V.; Alves, E.; Alves, L.C.; Barradas, N.P.; Duffar, Th.; Franco, N.; Marques, C.; Mitric, A.

    2005-01-01

    Low band gap III-V semiconductors are researched for applications in thermophotovoltaic technology. GaSb crystal is often used as a substrate. Ga 1-x In x Sb is also a promising substrate material, because its lattice parameters can be adjusted by controlling x. We used a new method to synthesise GaSb and GaInSb, in which a high frequency alternate magnetic field is used to heat, to melt and to mix the elements. We present a compositional and structural characterisation of the materials using a combination of complementary techniques. Rutherford backscattering was used to determine accurately the composition of the GaSb. With proton induced X-ray emission in conjunction with a 3 x 3 μm 2 micro-beam we studied the homogeneity of the samples. Structural analysis and phase identification were done with X-ray diffraction. The results for GaSb show a homogeneous composition while the GaInSb samples were found to be strongly heterogeneous at the end of the ingot. The ingots produced are competitive feed material, when compared to other growth techniques, to be used in a second step for the production of good quality ternary crystals

  1. The micro-magnetic structures of Mn sup + ion-implanted GaSb

    Zhang Fu Qiang; Liu Zhi Kai

    2003-01-01

    The micro-magnetic structures of Mn sup + ion-implanted GaSb are studied using a magnetic force microscope (MFM). MFM images reveal that there are many magnetic domains with different magnetization directions in our samples. The magnetic domain structures and the magnetization direction of typical MFM patterns are analyzed by numeric simulation. (author)

  2. Antisites and anisotropic diffusion in GaAs and GaSb

    Tahini, H. A.; Bracht, H.; Chroneos, Alexander; Grimes, R. W.; Murphy, S. T.; Schwingenschlö gl, Udo

    2013-01-01

    The significant diffusion of Ga under Ga-rich conditions in GaAs and GaSb is counter intuitive as the concentration of Ga vacancies should be depressed although Ga vacancies are necessary to interpret the experimental evidence for Ga transport

  3. Chemical and electrical properties of (NH4)2S passivated GaSb surface

    Tao Dongyan; Cheng Yu; Liu Jingming; Su Jie; Liu Tong; Yang Fengyun; Wang Fenghua; Cao Kewei; Dong Zhiyuan; Zhao Youwen

    2015-01-01

    The surface chemical properties of gallium antimonide (GaSb) after ammonium sulfide ((NH 4 ) 2 S) solution passivation have been studied by X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (TOF-SIMS) and I–V measurement. An advantage of neutral (NH 4 ) 2 S + S solution over pure (NH 4 ) 2 S solution and alkaline (NH 4 ) 2 S + S solution has been found in the ability to passivate the GaSb surface by contrast and comparison. It has been found that alkaline (NH 4 ) 2 S + S solution passivation effectively removes oxides of the GaSb surface and forms sulfide products to improve device performance. TOF-SIMS complementally demonstrates that pure (NH 4 ) 2 S passivation did form sulfide products, which are too soluble to really exist. The lowest roughness determined using a 3D optical profilometer and the highest improved SBD quality proved that neutral (NH 4 ) 2 S + S solution passivation worked much better in improving the surface properties of GaSb. (paper)

  4. A localized orbital description of ideal vacancies in GaP and GaSb

    Erbarut, E.; Tomak, M.

    1986-10-01

    Gaussian orbitals of s and p symmetry and an empirical pseudopotential Hamiltonian is employed for the study of electronic structures of ideal vacancies in GaP and GaSb. A reasonably accurate description of band structures and densities of states are attained. (author)

  5. Beryllium implant activation and damage recovery study in n-type GaSb

    Rahimi, N.; Behzadirad, M.; Renteria, Emma J.; Shima, D. M.; Muniz, Ayse J.; Busani, T.; Lavrova, Olga; Balakrishnan, G.; Lester, L. F.

    2014-03-01

    Damage induced by the implantation of beryllium in n-type GaSb and its removal by Rapid Thermal Annealing (RTA) are studied in detail by Atomic Force Microscopy (AFM), Cross Sectional Transmission Electron Microscopy (XTEM) and Energy Dispersive X-ray Spectroscopy (EDS). RTA has been implemented with different times and temperatures in order to optimize ion activation and to avoid Sb outdiffusion during the process. Results indicate a lattice quality that is close to pristine GaSb for samples annealed at 600 °C for 10s using a thick Si3N4 capping layer. Electrical response of the implanted diodes is measured and characterized as function of different annealing conditions.

  6. Study of the Local Environment of Mn Ions Implanted in GaSb

    Wolska, A.; Lawniczak-Jablonska, K.; Klepka, M.T.; Barcz, A.; Hallen, A.; Arvanitis, D.

    2010-01-01

    The first attempts to establish an implantation process leading to formation of ferromagnetic inclusions inside the GaSb matrix are presented. Gallium antimonide containing ferromagnetic MnSb precipitations is considered as a promising material for novel spintronic applications. It is possible to obtain such inclusions during the molecular beam epitaxy (MBE) growth. However, for commercial application it would be also important to find an optimal way of producing this kind of inclusions by Mn ions implantation. In order to achieve this goal, several parameters of implantation and post annealing procedures were tested. The ion energy was kept at 10 keV or 150 keV and four different ion doses were applied, as well as various annealing conditions. The analysis of X-ray absorption spectra allowed to estimate the local atomic order around Mn atoms. Depending on the implantation energy and annealing processes, the manganese oxides or manganese atoms located in a heavily defected GaSb matrix were observed. The performed analysis helped in indicating the main obstacles in formation of MnSb inclusions inside the GaSb matrix by Mn ion implantation. (author)

  7. Nanosecond pulsed laser induced self-organized nano-dots patterns on GaSb surface

    Yoshida, Yutaka, E-mail: yyoshida@cris.hokudai.ac.jp [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan); Creative Research Institution Sousei, Hokkaido University, N21, W10, Kita-ku, Sapporo 001-0021, Hokkaido (Japan); Oosawa, Kazuya; Wajima, Jyunya; Watanabe, Seiichi [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan); Matsuo, Yasutaka [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Hokkaido (Japan); Kato, Takahiko [Hitachi Research Laboratory, Hitachi, Ltd., 7-1-1 Omika, Hitachi-shi 319-1292, Ibaraki-ken (Japan); Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan)

    2014-07-01

    We report a technique for formation of two-dimensional (2D) nanodot (ND) patterns on gaillium antimoide (GaSb) using a nanosecond pulsed laser irradiation with 532 nm wavelength. The patterns have formed because of the interference and the self-organization under energy deposition of the laser irradiation, which induced the growth of NDs on the local area. The NDs are grown and shrunken in the pattern by energy depositions. In the laser irradiation with average laser energy density of 35 mJ cm⁻², large and small NDs are formed on GaSb surface. The large NDs have grown average diameter from 160 to 200 nm with increase of laser pulses, and the small NDs have shrunken average diameter from 75 to 30 nm. The critical dot size is required about 107 nm for growth of the NDs in the patterns. Nanosecond pulsed laser irradiation can control the self-organized ND size on GaSb in air as a function of the laser pulses.

  8. Nature of metastable amorphous-to-crystalline reversible phase transformations in GaSb

    Kalkan, B. [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 20015 (United States); Edwards, T. G.; Sen, S. [Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616 (United States); Raoux, S. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2013-08-28

    The structural, thermodynamic, and kinetic aspects of the transformations between the metastable amorphous and crystalline phases of GaSb are investigated as a function of pressure at ambient temperature using synchrotron x-ray diffraction experiments in a diamond anvil cell. The results are consistent with the hypothesis that the pressure induced crystallization of amorphous GaSb into the β-Sn crystal structure near ∼5 GPa is possibly a manifestation of an underlying polyamorphic phase transition between a semiconducting, low density and a metallic, high density amorphous (LDA and HDA, respectively) phases. In this scenario, the large differences in the thermal crystallization kinetics between amorphous GaSb deposited in thin film form by sputtering and that prepared by laser melt quenching may be related to the relative location of the glass transition temperature of the latter in the pressure-temperature (P-T) space with respect to the location of the critical point that terminate the LDA ↔ HDA transition. The amorphous →β-Sn phase transition is found to be hysteretically reversible as the β-Sn phase undergoes decompressive amorphization near ∼2 GPa due to the lattice instabilities that give rise to density fluctuations in the crystal upon decompression.

  9. Nature of metastable amorphous-to-crystalline reversible phase transformations in GaSb

    Kalkan, B.; Edwards, T. G.; Raoux, S.; Sen, S.

    2013-08-01

    The structural, thermodynamic, and kinetic aspects of the transformations between the metastable amorphous and crystalline phases of GaSb are investigated as a function of pressure at ambient temperature using synchrotron x-ray diffraction experiments in a diamond anvil cell. The results are consistent with the hypothesis that the pressure induced crystallization of amorphous GaSb into the β-Sn crystal structure near ˜5 GPa is possibly a manifestation of an underlying polyamorphic phase transition between a semiconducting, low density and a metallic, high density amorphous (LDA and HDA, respectively) phases. In this scenario, the large differences in the thermal crystallization kinetics between amorphous GaSb deposited in thin film form by sputtering and that prepared by laser melt quenching may be related to the relative location of the glass transition temperature of the latter in the pressure-temperature (P-T) space with respect to the location of the critical point that terminate the LDA ↔ HDA transition. The amorphous → β-Sn phase transition is found to be hysteretically reversible as the β-Sn phase undergoes decompressive amorphization near ˜2 GPa due to the lattice instabilities that give rise to density fluctuations in the crystal upon decompression.

  10. Nature of metastable amorphous-to-crystalline reversible phase transformations in GaSb

    Kalkan, B.; Edwards, T. G.; Sen, S.; Raoux, S.

    2013-01-01

    The structural, thermodynamic, and kinetic aspects of the transformations between the metastable amorphous and crystalline phases of GaSb are investigated as a function of pressure at ambient temperature using synchrotron x-ray diffraction experiments in a diamond anvil cell. The results are consistent with the hypothesis that the pressure induced crystallization of amorphous GaSb into the β-Sn crystal structure near ∼5 GPa is possibly a manifestation of an underlying polyamorphic phase transition between a semiconducting, low density and a metallic, high density amorphous (LDA and HDA, respectively) phases. In this scenario, the large differences in the thermal crystallization kinetics between amorphous GaSb deposited in thin film form by sputtering and that prepared by laser melt quenching may be related to the relative location of the glass transition temperature of the latter in the pressure-temperature (P-T) space with respect to the location of the critical point that terminate the LDA ↔ HDA transition. The amorphous →β-Sn phase transition is found to be hysteretically reversible as the β-Sn phase undergoes decompressive amorphization near ∼2 GPa due to the lattice instabilities that give rise to density fluctuations in the crystal upon decompression

  11. Formation, atomic structure, and electronic properties of GaSb quantum dots in GaAs

    Timm, R.

    2007-12-14

    In this work, cross-sectional scanning tunneling microscopy and spectroscopy are used for the first time to study the shape, size, strain, chemical composition, and electronic properties of capped GaSb/GaAs QDs at the atomic scale. By evaluating such structural results on a variety of nanostructures built using different epitaxy methods and growth conditions, details on the underlying QD formation processes can be revealed. A cross-over from flat quantum wells (QWs) to optically active QDs can be observed in samples grown by metalorganic chemical vapor deposition (MOCVD) with increasing amount of GaSb, including self-assembled Sb accumulations within a still two-dimensional layer and tiny three-dimensional GaSb islands probably acting as precursor structures. The QWs consist of significantly intermixed material with stoichiometries of maximally 50% GaSb, additionally exhibiting small gaps filled with GaAs. A higher GaSb content up to nearly pure material is found in the QDs, being characterized by small sizes of up to 8 nm baselength and about 2 nm height. In spite of the intermixing, all nanostructures have rather abrupt interfaces, and no significant Sb segregation in growth direction is observed. This changes completely when molecular beam epitaxy (MBE) is used as growth method, in which case individual Sb atoms are found to be distributed over several nm above the nanostructures. Massive group-V atomic exchange processes are causing this strong inter-mixing and Sb segregation during GaAs overgrowth. In combination with the large strain inherent to GaSb/GaAs QDs, this segregation upon overgrowth is assumed to be the reason for a unique structural phenomenon: All MBE-grown QDs, independent of the amount of deposited GaSb, exhibit a ring structure, consisting of a ring body of high GaSb content and a more or less extended central gap filled with GaAs. These rings have formed in a self-assembled way even when the initial GaSb layer was overgrown considerably fast

  12. Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

    Yokoyama, Masafumi, E-mail: yokoyama@mosfet.t.u-tokyo.ac.jp; Takenaka, Mitsuru; Takagi, Shinichi [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); JST-CREST, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Asakura, Yuji [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Yokoyama, Haruki [NTT Photonics Laboratories, NTT Corporation, Atsugi 243-0198 (Japan)

    2014-06-30

    We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The Al{sub 2}O{sub 3}/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (D{sub it}) of ∼4.5 × 10{sup 13 }cm{sup −2} eV{sup −1}. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

  13. Improved GaSb surfaces using a (NH4)2S/(NH4)2S04 solution

    Murape, D.M.; Eassa, N.; Nyamhere, C.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

    2012-01-01

    Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH 4 ) 2 S/(NH 4 ) 2 SO 4 ) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height (φ b ) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at −0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb–O, present on the as-received material is effectively removed on treating with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ]+S) and (NH 4 ) 2 S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is ≤8.5 nm.

  14. GaSb grown from Sn solvent at low temperatures by LPE

    Compean, V H; Anda, F de; Mishurnyi, V A; Gorbatchev, A Yu, E-mail: fdeanda@cactus.iico.uaslp.m [Universidad Autonoma de San Luis Potosi, Instituto de Investigacion en Comunicacion Optica, Av. Karakorum 1470, Col. Lomas 4a Sec., San Luis Potosi, SLP, CP 78210 (Mexico)

    2009-05-01

    The LPE growth of GaSb using Sn as a solvent has been studied in the temperature range 250-370 C and using liquid solutions covering a wide range of compositions. In order to find the growth conditions the phase diagram has been determined experimentally around the same temperature region. It is shown the Sn incorporates into the grown layers and that it behaves as an acceptor. The photoluminescence spectra of the grown layers with different Sn contents show characteristic peaks that can be attributed to different recombination processes.

  15. Growth morphology and structure of bismuth thin films on GaSb(110)

    Gemmeren, T. van; Lottermoser, L.; Falkenberg, G.

    1998-01-01

    Photoelectron spectroscopy, low-energy electron diffraction, scanning tunneling microscopy and surface X-ray diffraction were used to investigate the growth of thin layers of bismuth on GaSb(110). At submonolayer coverages, growth of two-dimensional islands occurs. A uniform (1 x I)-reconstructio...... that the (1 x 1)-phases formed by antimony and bismuth adsorbates on (110) surfaces of other III-V compound semiconductors are also described by the epitaxial continued layer model. (C) 1998 Elsevier Science B.V. All rights reserved....

  16. Effect of tellurium on viscosity and liquid structure of GaSb melts

    Ji Leilei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China); Geng Haoran [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)], E-mail: mse_genghr@ujn.edu.cn; Sun Chunjing [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Teng Xinying; Liu Yamei [School of Material Science and Engineering, Jinan University, Jinan 250022 (China)

    2008-04-03

    The behavior of GaSb melt with tellurium addition was investigated using viscometer and differential scanning calorimetry (DSC). Normally, the viscosity of all melts measured decreased with the increasing temperature. However, anomalous transition points were observed in the temperature dependence of viscosity for Ga-Sb-Te system. Corresponded with the abnormal points on the viscosity-temperature curves, there were thermal effect peaks on the DSC curves. Furthermore, viscous activation energy and flow units of these melts and their structural features were discussed in this paper.

  17. GASB proposes new standards for financial reporting of postemployment benefits by state and local governments.

    Johnson, Karl D

    2003-03-01

    GASB has proposed new standards that will affect the way in which governments report postemployment health care benefits in audited external financial statements, resulting in more complete and transparent reporting by employers and plans and more relevant and useful information for the users of governmental financial reports. This article provides an overview of current financial reporting standards and practice, the financial reporting objectives of the project, the proposed measurement approach, noteworthy specific proposals, and the projected timetable for completion of the project and implementation of the new standards.

  18. Antisites and anisotropic diffusion in GaAs and GaSb

    Tahini, H. A.

    2013-10-02

    The significant diffusion of Ga under Ga-rich conditions in GaAs and GaSb is counter intuitive as the concentration of Ga vacancies should be depressed although Ga vacancies are necessary to interpret the experimental evidence for Ga transport. To reconcile the existence of Ga vacancies under Ga-rich conditions, transformation reactions have been proposed. Here, density functional theory is employed to calculate the formation energies of vacancies on both sublattices and the migration energy barriers to overcome the formation of the vacancy-antisite defect. Transformation reactions enhance the vacancy concentration in both materials and migration energy barriers indicate that Ga vacancies will dominate.

  19. Development of porous structures in GaSb by ion irradiation

    Jacobi, C.C.; Steinbach, T.; Wesch, W.

    2012-01-01

    Ion irradiation of GaSb causes not only defect formation but also leads to the formation of a porous structure. To study the behaviour of this structural modification, GaSb was irradiated with 6 MeV Iodine ions and ion fluences from 5 × 10 12 to 6 × 10 15 ions/cm 2 . The samples were investigated by step height measurements and scanning electron microscopy (SEM). Experiments were performed with two different procedures: (CI) Continuous Irradiation of samples followed by measurements of the step height in air and (SI) Stepwise Irradiation of samples with measurements of the step height in air between subsequent irradiations. Samples irradiated continuously, show a linear increase of the step height with increasing ion fluence up to 1.5 × 10 14 ions/cm 2 followed by a steeper, linear increase for higher ion fluences up to a step height of 32 μm. This swelling is induced by a formation of voids, and the two different slopes can be explained by a transformation from isolated voids to a rod like structure. For samples irradiated accordingly to procedure (SI), the step height shows the same behaviour up to an ion fluence of 1.5 × 10 14 ions/cm 2 resulting in a step height of ≈3 μm but then decreases with further irradiation. The latter effect is caused by a compaction of the porous structure.

  20. Redundant Sb condensation on GaSb epilayers grown by molecular beam epitaxy during cooling procedure

    Arpapay, B.; Şahin, S.; Arıkan, B.; Serincan, U.

    2014-01-01

    The effect of four different cooling receipts on the surface morphologies of unintentionally-doped GaSb epilayers on GaSb (100) substrates grown by molecular beam epitaxy is reported. Those receipts include three different Sb beam equivalent pressure (BEP) levels and two different termination temperatures. Surface morphologies of epilayers were examined by wet etching, surface profiler, atomic force microscopy, scanning electron microscopy and Raman spectroscopy. The results demonstrate that during the cooling period, a Sb BEP of 4.00 × 10 −4 Pa at a termination temperature of 400 °C induces a smooth surface without Sb condensation whereas same Sb BEP at a termination temperature of 350 °C forms a 300 nm thick Sb layer on the surface. In addition, it is revealed that by applying a wet etching procedure and using a surface profiler it is possible to identify this condensed layer from the two-sloped feature of mesa profile. - Highlights: • Sb beam flux termination temperature is crucial for redundant Sb condensation. • Sb beam flux level has a role on the thickness of redundant condensed Sb layer. • Redundant Sb layer thickness can be measured by two-sloped mesa structure

  1. Isolating GaSb Membranes Grown Metamorphically on GaAs Substrates Using Highly Selective Substrate Removal Etch Processes

    Renteria, E. J.; Muniz, A. J.; Addamane, S. J.; Shima, D. M.; Hains, C. P.; Balakrishnan, G.

    2015-05-01

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11,000 ± 2000, whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2- μm-thick GaSb epilayers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high- resolution x-ray diffraction and atomic force microscopy.

  2. Type II GaSb quantum ring solar cells under concentrated sunlight.

    Tsai, Che-Pin; Hsu, Shun-Chieh; Lin, Shih-Yen; Chang, Ching-Wen; Tu, Li-Wei; Chen, Kun-Cheng; Lay, Tsong-Sheng; Lin, Chien-Chung

    2014-03-10

    A type II GaSb quantum ring solar cell is fabricated and measured under the concentrated sunlight. The external quantum efficiency confirms the extended absorption from the quantum rings at long wavelength coinciding with the photoluminescence results. The short-circuit current of the quantum ring devices is 5.1% to 9.9% more than the GaAs reference's under various concentrations. While the quantum ring solar cell does not exceed its GaAs counterpart in efficiency under one-sun, the recovery of the open-circuit voltages at higher concentration helps to reverse the situation. A slightly higher efficiency (10.31% vs. 10.29%) is reported for the quantum ring device against the GaAs one.

  3. Radioisotope thermal photovoltaic application of the GaSb solar cell

    Morgan, M. D.; Horne, W. E.; Day, A. C.

    1991-01-01

    An examination of a RTVP (radioisotopic thermophotovoltaic) conceptual design has shown a high potential for power densities well above those achievable with radioisotopic thermoelectric generator (RTG) systems. An efficiency of 14.4 percent and system specific power of 9.25 watts/kg were predicted for a system with sixteen GPHS (general purpose heat source) sources operating at 1100 C. The models also showed a 500 watt system power by the strontium-90 isotope at 1200 C at an efficiency of 17.0 percent and a system specific power of 11.8 watts/kg. The key to this level of performance is a high-quality photovoltaic cell with narrow bandgap and a reflective rear contact. Recent work at Boeing on GaSb cells and transparent back GaAs cells indicate that such a cell is well within reach.

  4. Staircase and saw-tooth field emission steps from nanopatterned n-type GaSb surfaces

    Kildemo, M.; Le Roy, S.; Søndergård, E.

    2009-01-01

    High resolution field emission experiments from nanopatterned GaSb surfaces consisting of densely packed nanocones prepared by low ion-beam-energy sputtering are presented. Both uncovered and metal-covered nanopatterned surfaces were studied. Surprisingly, the field emission takes place by regular steps in the field emitted current. Depending on the field, the steps are either regular, flat, plateaus, or saw-tooth shaped. To the author’s knowledge, this is the first time that such results have been reported. Each discrete jump in the field emission may be understood in terms of resonant tunneling through an extended surface space charge region in an n-type, high aspect ratio, single GaSb nanocone. The staircase shape may be understood from the spatial distribution of the aspect ratio of the cones.

  5. Staircase and saw-tooth field emission steps from nanopatterned n-type GaSb surfaces

    Kildemo, M.; Levinsen, Y. Inntjore; Le Roy, S.; Soenderga ring rd, E. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondlieim (Norway); Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondlieim, Norway and AB CERN, CH- 1211 Geneva 23 (Switzerland); Laboratoire Surface du Verre et Interfaces, UMR 125 Unite Mixte de Recherche CNRS/Saint-Gobain Laboratoire, 39 Quai Lucien Lefranc, F-93303 Aubervilliers Cedex (France)

    2009-09-15

    High resolution field emission experiments from nanopatterned GaSb surfaces consisting of densely packed nanocones prepared by low ion-beam-energy sputtering are presented. Both uncovered and metal-covered nanopatterned surfaces were studied. Surprisingly, the field emission takes place by regular steps in the field emitted current. Depending on the field, the steps are either regular, flat, plateaus, or saw-tooth shaped. To the author's knowledge, this is the first time that such results have been reported. Each discrete jump in the field emission may be understood in terms of resonant tunneling through an extended surface space charge region in an n-type, high aspect ratio, single GaSb nanocone. The staircase shape may be understood from the spatial distribution of the aspect ratio of the cones.

  6. Isolating GaSb membranes grown metamorphically on GaAs substrates using highly selective substrate removal etch processes

    Lavrova, Olga [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials; Balakrishnan, Ganesh [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering. Center for High Technology Materials

    2017-02-24

    The etch rates of NH4OH:H2O2 and C6H8O7:H2O2 for GaAs and GaSb have been investigated to develop a selective etch for GaAs substrates and to isolate GaSb epilayers grown on GaAs. The NH4OH:H2O2 solution has a greater etch rate differential for the GaSb/GaAs material system than C6H8O7:H2O2 solution. The selectivity of NH4OH:H2O2 for GaAs/GaSb under optimized etch conditions has been observed to be as high as 11471 ± 1691 whereas that of C6H8O7:H2O2 has been measured up to 143 ± 2. The etch contrast has been verified by isolating 2 μm thick GaSb epi-layers that were grown on GaAs substrates. GaSb membranes were tested and characterized with high-resolution X-Ray diffraction (HR-XRD) and atomic force microscopy (AFM).

  7. Silver nanoparticles on GaSb nanodots: a LSPR-boosted binary platform for broadband light harvesting and SERS

    Bhatnagar, Mukul, E-mail: mkbh10@gmail.com; Ranjan, Mukesh; Mukherjee, Subroto [FCIPT, Institute for Plasma Research (India)

    2015-02-15

    We report the LSPR-augmented optical response of silver nanoparticle-topped GaSb nanodots produced by low-energy ion beam irradiation. Nanostructure ordering and interdot gap play crucial roles for inducing the LSPR effect, enhancing the absorbing capacity of the structure as validated by reflection measurements. The measured size of silver-capped GaSb nanodot varies from 28 to 48 nm. Enhanced plasmon coupling for the 600 eV configuration initiates the presence of giant electromagnetic fields as confirmed by LSPR and SERS measurements. Anisotropic Bruggeman effective medium approximation was performed to match the experimentally observed optical response of the nanostructure. Calculated screening factor values of 0.29 and 0.23 for 600 and 800 eV ion energy produced nanodot configurations were obtained, respectively, which are in tune with the measured reflected and SERS signal. The calculated dielectric constants confirm the directional anisotropy along the length of the silver-capped GaSb nanodots. The proposed model successfully matches the void fraction and nanostructure height in accordance with SEM and reported TEM measurements. Thus, the model developed can be used to optimize the maximum plasmonic coupling efficiency among the dots. We propose two key applications for this nanostructure, first as an absorptive substrate for deep space photovoltaics and second to act as an effective SERS substrate.

  8. Optimization of growth parameters for MOVPE-grown GaSb and Ga1−xInxSb

    Miya, S.S.; Wagener, V.; Botha, J.R.

    2012-01-01

    The triethylgallium/trimethylantimony (TEGa/TMSb) precursor combination was used for the metal-organic vapour phase epitaxial growth of GaSb at a growth temperature of 520 °C at atmospheric pressure. Trimethylindium was added in the case of Ga 1−x In x Sb growth. The effects of group V flux to group III flux ratio (V/III ratio) on the crystallinity and optical properties of GaSb layers are reported. It has been observed from the crystalline quality and optical properties that nominal V/III ratios of values greater than unity are required for GaSb epitaxial layers grown at this temperature. It has also been shown that Ga 1−x In x Sb can be grown using TEGa as a source of gallium species at atmospheric pressure. The relationship between Ga 1−x In x Sb vapour composition and solid composition has been studied at a V/III ratio of 0.78.

  9. Argon-ion-induced formation of nanoporous GaSb layer: Microstructure, infrared luminescence, and vibrational properties

    Datta, D. P.; Som, T., E-mail: tsom@iopb.res.in [SUNAG Laboratory, Institute of Physics, Bhubaneswar, Odisha 751 005 (India); Kanjilal, A. [Department of Physics, Shiv Nadar University, Uttar Pradesh 201 314 (India); Satpati, B. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Dhara, S. [Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Das, T. D. [Department of Electronic Science, University of Calcutta, APC Road, Kolkata 700 009 (India); Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2014-07-21

    Room temperature implantation of 60 keV Ar{sup +}-ions in GaSb to the fluences of 7 × 10{sup 16} to 3 × 10{sup 18} ions cm{sup −2} is carried out at two incidence angles, viz 0° and 60°, leading to formation of a nanoporous layer. As the ion fluence increases, patches grow on the porous layer under normal ion implantation, whereas the porous layer gradually becomes embedded under a rough top surface for oblique incidence of ions. Grazing incidence x-ray diffraction and cross-sectional transmission electron microscopy studies reveal the existence of nanocrystallites embedded in the ion-beam amorphized GaSb matrix up to the highest fluence used in our experiment. Oxidation of the nanoporous layers becomes obvious from x-ray photoelectron spectroscopy and Raman mapping. The correlation of ion-beam induced structural modification with photoluminescence signals in the infrared region has further been studied, showing defect induced emission of additional peaks near the band edge of GaSb.

  10. Preclinical and first clinical experience with the gastrin-releasing peptide receptor-antagonist [68Ga]SB3 and PET/CT

    Maina, Theodosia; Charalambidis, David; Nock, Berthold A.; Bergsma, Hendrik; Krenning, Eric P.; Kulkarni, Harshad R.; Mueller, Dirk; Baum, Richard P.; Jong, Marion de

    2016-01-01

    Gastrin-releasing peptide receptors (GRPR) represent attractive targets for tumor diagnosis and therapy because of their overexpression in major human cancers. Internalizing GRPR agonists were initially proposed for prolonged lesion retention, but a shift of paradigm to GRPR antagonists has recently been made. Surprisingly, radioantagonists, such as [ 99m Tc]DB1 ( 99m Tc-N 4 '-DPhe 6 ,Leu-NHEt 13 BBN(6-13)), displayed better pharmacokinetics than radioagonists, in addition to their higher inherent biosafety. We introduce here [ 68 Ga]SB3, a [ 99m Tc]DB1 mimic-carrying, instead of the 99m Tc-binding tetraamine, the chelator DOTA for labeling with the PET radiometal 68 Ga. Competition binding assays of SB3 and [ nat Ga]SB3 were conducted against [ 125 I-Tyr 4 ]BBN in PC-3 cell membranes. Blood samples collected 5 min postinjection (pi) of the [ 67 Ga]SB3 surrogate in mice were analyzed using high-performance liquid chromatography (HPLC) for degradation products. Likewise, biodistribution was performed after injection of [ 67 Ga]SB3 (37 kBq, 100 μL, 10 pmol peptide) in severe combined immunodeficiency (SCID) mice bearing PC-3 xenografts. Eventually, [ 68 Ga]SB3 (283 ± 91 MBq, 23 ± 7 nmol) was injected into 17 patients with breast (8) and prostate (9) cancer. All patients had disseminated disease and had received previous therapies. PET/CT fusion images were acquired 60-115 min pi. SB3 and [ nat Ga]SB3 bound to the human GRPR with high affinity (IC 50 : 4.6 ± 0.5 nM and 1.5 ± 0.3 nM, respectively). [ 67 Ga]SB3 displayed good in vivo stability (>85 % intact at 5 min pi). [ 67 Ga]SB3 showed high, GRPR-specific and prolonged retention in PC-3 xenografts (33.1 ± 3.9%ID/g at 1 h pi - 27.0 ± 0.9%ID/g at 24 h pi), but much faster clearance from the GRPR-rich pancreas (∼160%ID/g at 1 h pi to <17%ID/g at 24 h pi) in mice. In patients, [ 68 Ga]SB3 elicited no adverse effects and clearly visualized cancer lesions. Thus, 4 out of 8 (50 %) breast cancer and 5 out of 9

  11. Four-phonon processes in the thermal conductivity of GaSb

    Aliev, M.I.; Arasly, D.G.; Guseinov, R.E.

    1978-01-01

    Phonon thermal conductivity of GaSb in the 300-700 K temperature range is studied by the light pulsed heating which is aimed at estimation of contributions of different polarized branches of acoustic oscillations into lattice thermal conductivity. The role of optico-acoustic interactions and multiphonon processes in phonon-phonon scattering at high temperatures is discussed. It is shown that the X thermal conductivity caused by the current carriers is negligibly small, and the Xsub(ph) phonon conductivity changes depending on temperature according to the Xsub(ph) approximately Tsup(-1.4) law. While calculating Xsub(ph) according to the Holland model taking into account phonon scattering on point defects the phonon thermal conductivity is given as a sum of contributions from longitudinal and transverse low-frequency Xsub(th1) and high-frequency Xsub(th2) acoustic phonons. It is established that at T>500 K Xsub(ph) is caused only by high-frequency transverse phonons and to explain the observed Xsub(ph) dependence on temperature it is necessary to introduce four-phonon process along with the three-phonon processes into intraphonon scattering

  12. First-principles calculations of the electronic and structural properties of GaSb

    Castaño-González, E.-E. [Universidad del Norte, Grupo de Investigación en Física Aplicada, Departamento de Física (Colombia); Seña, N. [Universidad Nacional de Colombia-Colombia, Departamento de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones (Colombia); Mendoza-Estrada, V.; González-Hernández, R., E-mail: rhernandezj@uninorte.edu.co [Universidad del Norte, Grupo de Investigación en Física Aplicada, Departamento de Física (Colombia); Dussan, A. [Universidad Nacional de Colombia-Colombia, Departamento de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones (Colombia); Mesa, F., E-mail: fredy.mesa@urosario.edu.co [Universidad del Rosario, Grupo NanoTech, Facultad de Ciencias Naturales y Matemáticas (Colombia)

    2016-10-15

    In this paper, we carried out first-principles calculations in order to investigate the structural and electronic properties of the binary compound gallium antimonide (GaSb). This theoretical study was carried out using the Density Functional Theory within the plane-wave pseudopotential method. The effects of exchange and correlation (XC) were treated using the functional Local Density Approximation (LDA), generalized gradient approximation (GGA): Perdew–Burke–Ernzerhof (PBE), Perdew-Burke-Ernzerhof revised for solids (PBEsol), Perdew-Wang91 (PW91), revised Perdew–Burke–Ernzerhof (rPBE), Armiento–Mattson 2005 (AM05) and meta-generalized gradient approximation (meta-GGA): Tao–Perdew–Staroverov–Scuseria (TPSS) and revised Tao–Perdew–Staroverov–Scuseria (RTPSS) and modified Becke-Johnson (MBJ). We calculated the densities of state (DOS) and band structure with different XC potentials identified and compared them with the theoretical and experimental results reported in the literature. It was discovered that functional: LDA, PBEsol, AM05 and RTPSS provide the best results to calculate the lattice parameters (a) and bulk modulus (B{sub 0}); while for the cohesive energy (E{sub coh}), functional: AM05, RTPSS and PW91 are closer to the values obtained experimentally. The MBJ, Rtpss and AM05 values found for the band gap energy is slightly underestimated with those values reported experimentally.

  13. Treatment for GaSb surfaces using a sulphur blended (NH4)2S/(NH4)2SO4 solution

    Murape, D.M.; Eassa, N.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

    2012-01-01

    A sulphur based chemical, [(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na 2 S·9H 2 O and (NH 4 ) 2 S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) than with (NH 4 ) 2 S or Na 2 S·9H 2 O, as evidenced by the ratio of the O 506eV to Sb 457eV AES peaks. XPS results reveal that Sb 2 S 3 /Sb 2 S 5 “replaces” Sb 2 O 3 /Sb 2 O 5 , suggesting that sulphur atoms substitute oxygen atoms in Sb 2 O 3 /Sb 2 O 5 to form Sb-S. It seems sulphurization only partially removes Ga 2 O 3 . Treatment with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

  14. Improved GaSb surfaces using a (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}S0{sub 4} solution

    Murape, D.M., E-mail: Davison.Murape@live.nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Eassa, N.; Nyamhere, C.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2012-05-15

    Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height ({phi}{sub b}) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at -0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb-O, present on the as-received material is effectively removed on treating with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}]+S) and (NH{sub 4}){sub 2}S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is {<=}8.5 nm.

  15. Utilizing Neon Ion Microscope for GaSb nanopatterning studies: Nanostructure formation and comparison with low energy nanopatterning

    El-Atwani, Osman; Huynh, Chuong; Norris, Scott

    2016-01-01

    Graphical abstract: - Highlights: • Carl Zeiss-neon ion microscope was used to irradiated GaSb surfaces with 5 keV neon. • In-situ imaging using helium beam and ex-situ imaging using an electron beam were performed. • Differences in imaging output between the helium and the electron beam were observed. • Transition occurred in the nanostructure type and formation mechanism as the energy is changed from 2 to 5 keV. • Collision cascade simulations suggested a transition toward bulk-driven mechanisms. - Abstract: Low energy irradiation of GaSb surfaces has been shown to lead to nanopillar formation. Being performed ex-situ, controlling the parameters of the ion beam for controlled nanopattern formation is challenging. While mainly utilized for imaging and cutting purposes, the development of multibeam (helium/neon) ion microscopes has opened the path towards the use of these microscopes for in-situ ion irradiation and nanopatterning studies. In this study, in-situ irradiation (neon ions)/imaging (helium ions) of GaSb surfaces is performed using Carl Zeiss-neon ion microscope at low energies (5 and 10 keV). Imaging with helium ions, nanodots were shown to form at particular fluences after which are smoothed. Ex-situ imaging with SEM showed nanopore formation of size controlled by the ion energy and fluence. Compared to lower energy ex-situ neon ion irradiation at similar fluxes, where nanopillars are formed, the results demonstrated a transition in the nanostructure type and formation mechanism as the energy is changed from 2 to 5 keV. Simulations show an increase in the ballistic diffusion and a decrease in the strength of phase separation as a function of ion energy in agreement with the suppression of nanopillar formation at higher energies. Collision cascade simulations suggest a transition toward bulk-driven mechanisms.

  16. Utilizing Neon Ion Microscope for GaSb nanopatterning studies: Nanostructure formation and comparison with low energy nanopatterning

    El-Atwani, Osman, E-mail: oelatwan25@gmail.com [School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Huynh, Chuong [Carl Zeiss Microscopy, LLC, One Corporation Way, Peabody, MA 01960 (United States); Norris, Scott [Department of Mathematics, Southern Methodist University, Dallas, TX 75275 (United States)

    2016-05-01

    Graphical abstract: - Highlights: • Carl Zeiss-neon ion microscope was used to irradiated GaSb surfaces with 5 keV neon. • In-situ imaging using helium beam and ex-situ imaging using an electron beam were performed. • Differences in imaging output between the helium and the electron beam were observed. • Transition occurred in the nanostructure type and formation mechanism as the energy is changed from 2 to 5 keV. • Collision cascade simulations suggested a transition toward bulk-driven mechanisms. - Abstract: Low energy irradiation of GaSb surfaces has been shown to lead to nanopillar formation. Being performed ex-situ, controlling the parameters of the ion beam for controlled nanopattern formation is challenging. While mainly utilized for imaging and cutting purposes, the development of multibeam (helium/neon) ion microscopes has opened the path towards the use of these microscopes for in-situ ion irradiation and nanopatterning studies. In this study, in-situ irradiation (neon ions)/imaging (helium ions) of GaSb surfaces is performed using Carl Zeiss-neon ion microscope at low energies (5 and 10 keV). Imaging with helium ions, nanodots were shown to form at particular fluences after which are smoothed. Ex-situ imaging with SEM showed nanopore formation of size controlled by the ion energy and fluence. Compared to lower energy ex-situ neon ion irradiation at similar fluxes, where nanopillars are formed, the results demonstrated a transition in the nanostructure type and formation mechanism as the energy is changed from 2 to 5 keV. Simulations show an increase in the ballistic diffusion and a decrease in the strength of phase separation as a function of ion energy in agreement with the suppression of nanopillar formation at higher energies. Collision cascade simulations suggest a transition toward bulk-driven mechanisms.

  17. Evolution of porous network in GaSb under normally incident 60 keV Ar{sup +}-ion irradiation

    Datta, D.P. [SUNAG Laboratory, Institute of Physics, Bhubaneswar 751 005, Odisha (India); Kanjilal, A. [Department of Physics, Shiv Nadar University, Gautam Budh Nagar 203 207, Uttar Pradesh (India); Garg, S.K. [SUNAG Laboratory, Institute of Physics, Bhubaneswar 751 005, Odisha (India); Sahoo, P.K. [School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar 751 005, Odisha (India); Satpati, B. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Kanjilal, D. [Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Som, T., E-mail: tsom@iopb.res.in [SUNAG Laboratory, Institute of Physics, Bhubaneswar 751 005, Odisha (India)

    2014-08-15

    Highlights: • We show the evolution of a nanoporous layer in GaSb under Ar{sup +}-ion bombardment at normal incidence in the hitherto unexplored high fluence regime, namely 7 × 10{sup 16}–3 × 10{sup 18} ions cm{sup −2}. • Fluence dependent formation and growth of patches on top of the nanoporous layer is demonstrated by scanning electron microscopy. • We also show high amount of oxidation of such ion-beam-generated nanoporous structures, with formation of Ga{sub 2}O{sub 3} and Sb{sub 2}O{sub 3}. • Our study reveals the presence of nanocrystallites within the porous layer even at the highest fluence used in the experiment. • We interpret the experimental observations through a qualitative model where we take into account the effect of re-deposition of atoms sputtered from the nanoporous layer during Ar{sup +}-ion irradiation of GaSb. - Abstract: GaSb(1 0 0) samples were irradiated with 60 keV Ar{sup +}-ions at normal incidence for fluences in the range of 7 × 10{sup 16} to 3 × 10{sup 18} ions cm{sup −2} at room temperature, showing gradual evolution of a porous surface layer containing interconnected nanofibers. In particular, fluence dependent formation of patches on the nanoporous layer is observed by scanning electron microscopy. Combined results of grazing incidence x-ray diffraction and transmission electron microscopy reveal the presence of nanocrystallites in the porous structures. Compositional analysis by x-ray photoelectron spectroscopy indicates the development of oxide phases, mainly Ga{sub 2}O{sub 3} and Sb{sub 2}O{sub 3} where the former increases with fluence. We have proposed a model addressing a competition between ion-induced-defect driven growth of the nanoporous layer and redeposition of sputtered target atoms on the growing layer.

  18. Chemical etching of a GaSb crystal incorporated with Mn grown by the Bridgman method under microgravity conditions

    Chen Xiaofeng; Chen Nuofu; Wu Jinliang; Zhang Xiulan; Chai Chunlin; Yu Yude

    2009-01-01

    A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemical etching method. By calculating various parameters of the convection, the striation patterns can be explained, and the critical value of the Taylor number, which characterizes the convective condition of the rotating magnetic field induced azimuthal flow, was shown. The stresses generated during crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given. (semiconductor materials)

  19. Chemical etching of a GaSb crystal incorporated with Mn grown by the Bridgman method under microgravity conditions

    Chen Xiaofeng; Chen Nuofu; Wu Jinliang; Zhang Xiulan; Chai Chunlin; Yu Yude, E-mail: xfchen@semi.ac.c, E-mail: nfchen@semi.ac.c [Key Laboratory of Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2009-08-15

    A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemical etching method. By calculating various parameters of the convection, the striation patterns can be explained, and the critical value of the Taylor number, which characterizes the convective condition of the rotating magnetic field induced azimuthal flow, was shown. The stresses generated during crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given. (semiconductor materials)

  20. Preclinical and first clinical experience with the gastrin-releasing peptide receptor-antagonist [{sup 68}Ga]SB3 and PET/CT

    Maina, Theodosia; Charalambidis, David; Nock, Berthold A. [INRASTES, NCSR ' ' Demokritos' ' , Molecular Radiopharmacy, Athens (Greece); Bergsma, Hendrik; Krenning, Eric P. [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Kulkarni, Harshad R.; Mueller, Dirk; Baum, Richard P. [Zentralklinik, Molecular Radiotherapy and Molecular Imaging, Bad Berka (Germany); Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Erasmus MC, Department of Radiology, Rotterdam (Netherlands)

    2016-05-15

    Gastrin-releasing peptide receptors (GRPR) represent attractive targets for tumor diagnosis and therapy because of their overexpression in major human cancers. Internalizing GRPR agonists were initially proposed for prolonged lesion retention, but a shift of paradigm to GRPR antagonists has recently been made. Surprisingly, radioantagonists, such as [{sup 99m}Tc]DB1 ({sup 99m}Tc-N{sub 4}'-DPhe{sup 6},Leu-NHEt{sup 13}BBN(6-13)), displayed better pharmacokinetics than radioagonists, in addition to their higher inherent biosafety. We introduce here [{sup 68}Ga]SB3, a [{sup 99m}Tc]DB1 mimic-carrying, instead of the {sup 99m}Tc-binding tetraamine, the chelator DOTA for labeling with the PET radiometal {sup 68}Ga. Competition binding assays of SB3 and [{sup nat}Ga]SB3 were conducted against [{sup 125}I-Tyr{sup 4}]BBN in PC-3 cell membranes. Blood samples collected 5 min postinjection (pi) of the [{sup 67}Ga]SB3 surrogate in mice were analyzed using high-performance liquid chromatography (HPLC) for degradation products. Likewise, biodistribution was performed after injection of [{sup 67}Ga]SB3 (37 kBq, 100 μL, 10 pmol peptide) in severe combined immunodeficiency (SCID) mice bearing PC-3 xenografts. Eventually, [{sup 68}Ga]SB3 (283 ± 91 MBq, 23 ± 7 nmol) was injected into 17 patients with breast (8) and prostate (9) cancer. All patients had disseminated disease and had received previous therapies. PET/CT fusion images were acquired 60-115 min pi. SB3 and [{sup nat}Ga]SB3 bound to the human GRPR with high affinity (IC{sub 50}: 4.6 ± 0.5 nM and 1.5 ± 0.3 nM, respectively). [{sup 67}Ga]SB3 displayed good in vivo stability (>85 % intact at 5 min pi). [{sup 67}Ga]SB3 showed high, GRPR-specific and prolonged retention in PC-3 xenografts (33.1 ± 3.9%ID/g at 1 h pi - 27.0 ± 0.9%ID/g at 24 h pi), but much faster clearance from the GRPR-rich pancreas (∼160%ID/g at 1 h pi to <17%ID/g at 24 h pi) in mice. In patients, [{sup 68}Ga]SB3 elicited no adverse effects and

  1. Limiting scattering processes in high-mobility InSb quantum wells grown on GaSb buffer systems

    Lehner, Ch. A.; Tschirky, T.; Ihn, T.; Dietsche, W.; Keller, J.; Fält, S.; Wegscheider, W.

    2018-05-01

    We present molecular beam epitaxial grown single- and double-side δ -doped InAlSb/InSb quantum wells with varying distances down to 50 nm to the surface on GaSb metamorphic buffers. We analyze the surface morphology as well as the impact of the crystalline quality on the electron transport. Comparing growth on GaSb and GaAs substrates indicates that the structural integrity of our InSb quantum wells is solely determined by the growth conditions at the GaSb/InAlSb transition and the InAlSb barrier growth. The two-dimensional electron gas samples show high mobilities of up to 349 000 cm2/Vs at cryogenic temperatures and 58 000 cm2/Vs at room temperature. With the calculated Dingle ratio and a transport lifetime model, ionized impurities predominantly remote from the quantum well are identified as the dominant source of scattering events. The analysis of the well-pronounced Shubnikov-de Haas oscillations reveals a high spin-orbit coupling with an effective g -factor of -38.4 in our samples. Along with the smooth surfaces and long mean free paths demonstrated, our InSb quantum wells are increasingly competitive for nanoscale implementations of Majorana mode devices.

  2. Reactive ion etching of GaSb, (Al,Ga)Sb, and InAs for novel device applications

    LaTulipe, D.C.; Frank, D.J.; Munekata, H.

    1991-01-01

    Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. The authors of this paper have studied the reactive ion etching characteristics of GaSb, (Al,Ga)Sb, and InAs in both methane/hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH 4 /H 2 , the etch rate of (Al,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200 Angstrom/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl 2 was found to yield anistropic profiles, with the etch rate of (Al,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to the InAs stop layer was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs- channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics

  3. Structural characterization of ZnTe grown by atomic-layer-deposition regime on GaAs and GaSb (100) oriented substrates

    Castillo-Ojeda, Roberto Saúl [Universidad Politécnica de Pachuca (Mexico); Díaz-Reyes, Joel; Peralta-Clara, María de la Cruz; Veloz-Rendón, Julieta Salomé, E-mail: joel_diaz_reyes@hotmail.com [Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tlaxcala, (Mexico); Galván-Arellano, Miguel [Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional (Mexico); Anda-Salazar, Francisco de [Instituto de Investigación en Comunicación Óptica, Universidad Autónoma de San Luis Potosí (Mexico); Contreras-Rascon, Jorge Indalecio [Departamento de Física, Universidad de Sonora (Mexico)

    2017-10-15

    This work presents the characterization of ZnTe nano layers grown on GaAs and GaSb (100) substrates by the Atomic Layer Deposition (ALD) regime. Under certain conditions, the alternating exposition of a substrate surface to the element vapours makes possible the growth of atomic layers in a reactor where the atmosphere is high-purity hydrogen. ZnTe was grown simultaneously on GaAs and GaSb at the same run, allowing, a comparison between the effects produced by the superficial processes due to the different used substrates, thereby eliminating possible unintended changes of growth parameters. Nano layers on GaSb maintained their shiny appearance even at temperatures near 420°C. It was found that for exposure times below 2.5 s there was not growth on GaAs, while for GaSb the shortest time was 1.5 s at 385°C. By HRXRD the peak corresponding to (004) diffraction plane of ZnTe was identified and investigated, the FWHM resulted very wide (600-800 arcsec) indicating a highly distorted lattice mainly due to mosaicity. Raman scattering shows the peak corresponding to LO-ZnTe, which is weak and slightly shifted in comparison with the reported for the bulk ZnTe at 210 cm{sup -1}. Additionally, the measurements suggest that the crystalline quality have a dependence with the growth temperature. (author)

  4. Methodology for Achieving GASB 34 Modified Approach Compliance Using US Navy "Smart Base" Facility Management Practices

    Crafts, Michael

    2002-01-01

    .... While the growth of enterprise software solutions for asset management has begun to change this, the high cost and complexity of such systems has primarily limited their implementation to large...

  5. Treatment for GaSb surfaces using a sulphur blended (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4} solution

    Murape, D.M., E-mail: Davison.Murape@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Eassa, N.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa)

    2012-07-01

    A sulphur based chemical, [(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na{sub 2}S{center_dot}9H{sub 2}O and (NH{sub 4}){sub 2}S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) than with (NH{sub 4}){sub 2}S or Na{sub 2}S{center_dot}9H{sub 2}O, as evidenced by the ratio of the O{sub 506eV} to Sb{sub 457eV} AES peaks. XPS results reveal that Sb{sub 2}S{sub 3}/Sb{sub 2}S{sub 5} 'replaces' Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5}, suggesting that sulphur atoms substitute oxygen atoms in Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5} to form Sb-S. It seems sulphurization only partially removes Ga{sub 2}O{sub 3}. Treatment with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

  6. Influence of magnetic and ultrasonic fields on coefficient of reflectivity of GaAs, GaSb and InAs crystals

    Zaveryukhin, B.N.; Zaveryukhina, N.N.; Zaveryukhina, E.V.; Volodarskiy, V.V.

    2007-01-01

    Full text: Previously we demonstrated for the first time in the world that ultrasonic waves of the megahertz range can change the transport properties and a structure of semiconductors. In this work we have experimentally studied the influence of ultrasonic treatment on the spectral coefficients of reflection R in the magnetic fields of the samples of GaAs-, GaSb- and InAs-crystals. The reflectance spectra in the magnetic field of the samples before and after the ultrasonic treatment (UST) for a certain time were measured in a broad wavelength range including ultraviolet, visible, and infrared spectral regions. The semi-insulating GaAs-crystals had a thickness d=100 μm and a working area S of up to 3sm 2 . The p-GaSb- crystals had an area of S=0.25sm 2 and d =250 μm. The base p-GaSb-layers possessed the concentration N=2·10 17 sm 3 and n-GaSb-layers with a thickness of 0.5 m were created by diffusion doping with phosphorus. Besides, the experiments were performed also for of the n-InAs-crystals. The samples of the InAs-n crystals had a thickness of 100 μm an area S = 0.25 sm 2 . Some remains of sulfuric (S) were discovered in InAs-samples. As could was see from the experiments, all the initial IR spectra measured for the samples with various dopant concentrations NP exhibit maximums (peaks) for 0.2 μm and minimum (holes) for. The reflectance spectra measured after UST for time of t > l hour clearly reveal a shift of the R minima toward longer wavelengths and a general decrease in the reflectance of each sample. The shift of the R is unambiguous evidence of the acoustically stimulated diffusion of impurity (phosphorus) inward of the samples. Discovered peaks and holes slitted and changed their sizes in the magnetic fields. It should be emphasized that behavior of the R spectra of the GaAs-, In As- and GaSb- samples is determined by the same mechanisms. Changes of the R spectra after the UST are explained by acoustically stimulated diffusion of the dopant inward

  7. Optimization of growth parameters for MOVPE-grown GaSb and Ga{sub 1-x}In{sub x}Sb

    Miya, S.S.; Wagener, V. [Department of Physics, Private Bag X 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6001 (South Africa); Botha, J.R., E-mail: reinhardt.botha@nmmu.ac.za [Department of Physics, Private Bag X 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6001 (South Africa)

    2012-05-15

    The triethylgallium/trimethylantimony (TEGa/TMSb) precursor combination was used for the metal-organic vapour phase epitaxial growth of GaSb at a growth temperature of 520 Degree-Sign C at atmospheric pressure. Trimethylindium was added in the case of Ga{sub 1-x}In{sub x}Sb growth. The effects of group V flux to group III flux ratio (V/III ratio) on the crystallinity and optical properties of GaSb layers are reported. It has been observed from the crystalline quality and optical properties that nominal V/III ratios of values greater than unity are required for GaSb epitaxial layers grown at this temperature. It has also been shown that Ga{sub 1-x}In{sub x}Sb can be grown using TEGa as a source of gallium species at atmospheric pressure. The relationship between Ga{sub 1-x}In{sub x}Sb vapour composition and solid composition has been studied at a V/III ratio of 0.78.

  8. Effects of a GaSb buffer layer on an InGaAs overlayer grown on Ge(111) substrates: Strain, twin generation, and surface roughness

    Kajikawa, Y.; Nishigaichi, M.; Tenma, S.; Kato, K.; Katsube, S.

    2018-04-01

    InGaAs layers were grown by molecular-beam epitaxy on nominal and vicinal Ge(111) substrates with inserting GaSb buffer layers. High-resolution X-ray diffraction using symmetric 333 and asymmetric 224 reflections was employed to analyze the crystallographic properties of the grown layers. By using the two reflections, we determined the lattice constants (the unit cell length a and the angle α between axes) of the grown layers with taking into account the rhombohedral distortion of the lattices of the grown layers. This allowed us the independent determination of the strain components (perpendicular and parallel components to the substrate surface, ε⊥ and ε//) and the composition x of the InxGa1-xAs layers by assuming the distortion coefficient D, which is defined as the ratio of ε⊥ against ε//. Furthermore, the twin ratios were determined for the GaSb and the InGaAs layers by comparing asymmetric 224 reflections from the twin domain with that from the normal domain of the layers. As a result, it has been shown that the twin ratio in the InGaAs layer can be decreased to be less than 0.1% by the use of the vicinal substrate together with annealing the GaSb buffer layer during the growth interruption before the InGaAs overgrowth.

  9. Electronic structure and magnetism of Mn-doped GaSb for spintronic applications: A DFT study

    Seña, N.; Dussan, A. [Departamento de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Universidad Nacional de Colombia, Bogotá (Colombia); Mesa, F. [Facultad de Ciencias Naturales y Matemáticas, Grupo NanoTech, Universidad del Rosario, Bogotá (Colombia); Castaño, E.; González-Hernández, R., E-mail: rhernandezj@uninorte.edu.co [Grupo de Investigación en Física Aplicada, Departamento de Física, Universidad del Norte, Barranquilla (Colombia)

    2016-08-07

    We have carried out first-principles spin polarized calculations to obtain comprehensive information regarding the structural, magnetic, and electronic properties of the Mn-doped GaSb compound with dopant concentrations: x = 0.062, 0.083, 0.125, 0.25, and 0.50. The plane-wave pseudopotential method was used in order to calculate total energies and electronic structures. It was found that the Mn{sub Ga} substitution is the most stable configuration with a formation energy of ∼1.60 eV/Mn-atom. The calculated density of states shows that the half-metallic ferromagnetism is energetically stable for all dopant concentrations with a total magnetization of about 4.0 μ{sub B}/Mn-atom. The results indicate that the magnetic ground state originates from the strong hybridization between Mn-d and Sb-p states, which agree with previous studies on Mn-doped wide gap semiconductors. This study gives new clues to the fabrication of diluted magnetic semiconductors.

  10. Behavior of GaSb (100) and InSb (100) surfaces in the presence of H{sub 2}O{sub 2} in acidic and basic cleaning solutions

    Seo, Dongwan; Na, Jihoon; Lee, Seunghyo; Lim, Sangwoo, E-mail: swlim@yonsei.ac.kr

    2017-03-31

    Highlights: • Surface behavior of GaSb and InSb was investigated in acidic and basic solutions. • H{sub 2}O{sub 2} plays a key role in the surface oxidation of GaSb and InSb in acidic hydrochloric acid/hydrogen peroxide mixture (HPM) solution. • GaSb and InSb surfaces were hardly oxidized in basic ammonium hydroxide/hydrogen peroxide mixture (APM) solution in the presence of H{sub 2}O{sub 2}. • The effect of dilution of APM solution on the oxidation of the InSb surface was minimal. • Surface characteristics of GaSb and InSb in HPM and APM solutions are mainly determined by the behaviors of the group III elements rather than the group V element. - Abstract: Gallium antimonide (GaSb) and indium antimonide (InSb) have attracted strong attention as new channel materials for transistors due to their excellent electrical properties and lattice matches with various group III–V compound semiconductors. In this study, the surface behavior of GaSb (100) and InSb (100) was investigated and compared in hydrochloric acid/hydrogen peroxide mixture (HPM) and ammonium hydroxide/hydrogen peroxide mixture (APM) solutions. In the acidic HPM solution, surface oxidation was greater and the etching rates of the GaSb and InSb surfaces increased when the solution is concentrated, which indicates that H{sub 2}O{sub 2} plays a key role in the surface oxidation of GaSb and InSb in acidic HPM solution. However, the GaSb and InSb surfaces were hardly oxidized in basic APM solution in the presence of H{sub 2}O{sub 2} because gallium and indium are in the thermodynamically stable forms of H{sub 2}GaO{sub 3}{sup −} and InO{sub 2}{sup −}, respectively. When the APM solution was diluted, however, the Ga on the GaSb surface was oxidized by H{sub 2}O, increasing the etching rate. However, the effect of dilution of the APM solution on the oxidation of the InSb surface was minimal; thus, the InSb surface was less oxidized than the GaSb surface and the change in the etching rate of In

  11. Measurements of ultrafast dynamics in a superconductor, YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, and a semiconductor, GaSb

    Smith, D.C

    1998-07-01

    Measurements of ultrafast dynamics in GaSb and YBa{sub 2}Cu{sub 3}O{sub 7-}{delta} (YBCO) have been made with 1 ps or better resolution using time-resolved optical spectroscopy; pump-probe transmission and reflection, and time-resolved Raman spectroscopy. The study of carrier dynamics in GaSb focuses on the scattering of electrons between the F and L conduction band valleys by zone-boundary phonons {gamma}-L scattering in bulk GaSb and a GaSb/AlSb multiple quantum well sample has been investigated in a series of room temperature degenerate pump-probe transmission experiments with near bandgap excitation. There is a clear difference in the dynamics between experiments where electrons excited in {gamma} can/cannot directly scatter to the L valleys. Ensemble Monte Carlo simulations are presented which are in good agreement with the experiments. The strength of {gamma}-L scattering is quantified using an intervalley deformation potential for a single 'effective' zone-boundary phonon (25meV). A deformation potential of 3.6{+-}0.4 eVA{sup -1} is consistent with both the bulk and quantum well results. The temperature dependence of the dynamics in bulk GaSb is also explored. Time-resolved Raman spectroscopy (E{sub laser}{approx}E{sub 0}+{delta}{sub 0}) has been used to study {gamma}-F scattering by measuring the dynamics of phonons emitted during intravalley scattering. All the measured non-equilibrium phonon populations have a component whose lifetime is greater the phonons anharmonic lifetime. This component is interpreted as following the return of electrons from L to {gamma}. Comparison of the results with the pump-probe experiments indicates that this return is slowed by blocking of {gamma} states. The study of YBCO consists of pump-probe transmission and reflection measurements of thin films and single crystals in both the normal and superconducting states. Measurements of dynamics have been made with a wide range of probe energies lower than in any

  12. Excitation power dependence of photoluminescence spectra of GaSb type-II quantum dots in GaAs grown by droplet epitaxy

    Kawazu, T., E-mail: KAWAZU.Takuya@nims.go.jp; Noda, T.; Sakuma, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sakaki, H. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511 (Japan)

    2016-04-15

    We investigated the excitation power P dependence of photoluminescence (PL) spectra of GaSb type-II quantum dots (QDs) in GaAs grown by droplet epitaxy. We prepared two QD samples annealed at slightly different temperatures (380 {sup o}C and 400 {sup o}C) and carried out PL measurements. The 20 {sup o}C increase of the annealing temperature leads to (1) about 140 and 60 times stronger wetting layer (WL) luminescence at low and high P, (2) about 45% large energy shift of QD luminescence with P, and (3) the different P dependence of the PL intensity ratio between the QD and the WL. These differences of the PL characteristics are explained by the effects of the WL.

  13. Surface and interfacial reaction study of half cycle atomic layer deposited HfO{sub 2} on chemically treated GaSb surfaces

    Zhernokletov, D. M. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Dong, H.; Brennan, B.; Kim, J. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Yakimov, M.; Tokranov, V.; Oktyabrsky, S. [College of Nanoscale Science and Engineering, University at Albany - SUNY, Albany, New York 12203 (United States); Wallace, R. M. [Department of Physics, University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)

    2013-04-01

    An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (XPS) study was conducted in order to investigate the evolution of the HfO{sub 2} dielectric interface with GaSb(100) surfaces after sulfur passivation and HCl etching, designed to remove the native oxides. With the first pulses of tetrakis(dimethylamido)hafnium(IV) and water, a decrease in the concentration of antimony oxide states present on the HCl-etched surface is observed, while antimony sulfur states diminished below the XPS detection limit on sulfur passivated surface. An increase in the amount of gallium oxide/sulfide is seen, suggesting oxygen or sulfur transfers from antimony to gallium during antimony oxides/sulfides decomposition.

  14. GASB Achieves Standardization, Recognition.

    Bissell, George E.

    1986-01-01

    In 1984 the Governmental Accounting Standards Board, created to solidify accounting principles for government entities, enumerated Generally Accepted Accounting Principles endorsed by the American Institute of Certified Public Accountants and the National Council on Governmental Accounting. These principles have recently been approved for school…

  15. GaSb based lasers operating near 2.3 .mu.m for high resolution absorption spectroscopy

    Civiš, Svatopluk; Horká-Zelenková, Veronika; Šimeček, Tomislav; Hulicius, Eduard; Pangrác, Jiří; Oswald, Jiří; Petříček, Otto; Rouillard, C.; Alibert, C.; Werner, R.

    2005-01-01

    Roč. 61, - (2005), s. 3066-3069 ISSN 1386-1425 R&D Projects: GA AV ČR KSK1010104; GA AV ČR IAA4040104; GA MŠk OC 715.50 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z1010914 Keywords : laser diode * absorption spectroscopy * gas detection * methane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.290, year: 2005

  16. GaSb quantum rings in GaAs/Al{sub x}Ga{sub 1−x}As quantum wells

    Hodgson, P. D., E-mail: pdhodgson@hotmail.co.uk; Hayne, M.; Robson, A. J.; Zhuang, Q. D. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Danos, L. [Department of Chemistry, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2016-01-28

    We report the results of continuous and time-resolved photoluminescence measurements on type-II GaSb quantum rings embedded within GaAs/Al{sub x}Ga{sub 1−x}As quantum wells. A range of samples were grown with different well widths, compensation-doping concentrations within the wells, and number of quantum-ring layers. We find that each of these variants have no discernible effect on the radiative recombination, except for the very narrowest (5 nm) quantum well. In contrast, single-particle numerical simulations of the sample predict changes in photoluminescence energy of up to 200 meV. This remarkable difference is explained by the strong Coulomb binding of electrons to rings that are multiply charged with holes. The resilience of the emission to compensation doping indicates that multiple hole occupancy of the quantum rings is required for efficient carrier recombination, regardless of whether these holes come from doping or excitation.

  17. Effects of Radiative Recombination and Photon Recycling on Minority Carrier Lifetime in Epitaxial GaINAsSb Lattice-matched to GaSb

    S Anikeev; D Donetsky; G Belenky; S Luryl; CA Wang; DA Shiau; M Dashiell; J Beausang; G Nichols

    2004-01-01

    Radiative coefficient (B) is a fundamental recombination parameter which is of importance for a variety of optoelectronic minority carrier devices. Radiative recombination was comprehensively studied for wide-bandgap III-V compounds, while for 0.5-0.6 eV materials experimental data are quite limited and demonstrate significant spreading. Here we report excess carrier lifetime in isotype double heterostructures (DHs) of 0.54-eV p-GaInAsSb capped with p-AlGaAsSb, and grown lattice-matched to GaSb. Lifetime was measured by time-resolved photoluminescence (dynamic lifetime) as well as by optical response to sinusoidal excitation (static lifetime). Wide range of GaInAsSb layer thickness was used to separate contributions from interface and radiative recombination processes. Radiative coefficient and recombination velocity at GaInAsSb/AlGaAsSb heterointerface were determined. Temperature dependence of lifetime demonstrated significant contribution of radiative effects to the total recombination

  18. Atomic layer deposition of Al2O3 on GaSb using in situ hydrogen plasma exposure

    Ruppalt, Laura B.; Cleveland, Erin R.; Champlain, James G.; Prokes, Sharka M.; Brad Boos, J.; Park, Doewon; Bennett, Brian R.

    2012-01-01

    In this report, we study the effectiveness of hydrogen plasma surface treatments for improving the electrical properties of GaSb/Al 2 O 3 interfaces. Prior to atomic layer deposition of an Al 2 O 3 dielectric, p-GaSb surfaces were exposed to hydrogen plasmas in situ, with varying plasma powers, exposure times, and substrate temperatures. Good electrical interfaces, as indicated by capacitance-voltage measurements, were obtained using higher plasma powers, longer exposure times, and increasing substrate temperatures up to 250 °C. X-ray photoelectron spectroscopy reveals that the most effective treatments result in decreased SbO x , decreased Sb, and increased GaO x content at the interface. This in situ hydrogen plasma surface preparation improves the semiconductor/insulator electrical interface without the use of wet chemical pretreatments and is a promising approach for enhancing the performance of Sb-based devices.

  19. New GasB-based single-mode diode lasers in the NIR and MIR spectral regime for sensor applications

    Milde, Tobias; Hoppe, Morten; Tatenguem, Herve; Honsberg, Martin; Mordmüller, Mario; O'Gorman, James; Schade, Wolfgang; Sacher, Joachim

    2018-02-01

    The NIR/MIR region between 1.8μm and 3.5μm contains important absorption lines for gas detection. State of the art are InP laser based setups, which show poor gain above 1.8μm and cannot be applied beyond 2.1μm. GaSb laser show a significantly higher output power (100mW for Fabry-Perot, 30mW for DFB). The laser design is presented with simulation and actual performance data. The superior performance of the GaSb lasers is verified in gas sensing applications. TDLAS and QEPAS measurements at trace gases like CH4, CO2 and N2O are shown to prove the spectroscopy performance.

  20. Real-time tunability of chip-based light source enabled by microfluidic mixing

    Olsen, Brian Bilenberg; Rasmussen, Torben; Balslev, Søren

    2006-01-01

    We demonstrate real-time tunability of a chip-based liquid light source enabled by microfluidic mixing. The mixer and light source are fabricated in SU-8 which is suitable for integration in SU-8-based laboratory-on-a-chip microsystems. The tunability of the light source is achieved by changing...... the concentration of rhodamine 6G dye inside two integrated vertical resonators, since both the refractive index and the gain profile are influenced by the dye concentration. The effect on the refractive index and the gain profile of rhodamine 6G in ethanol is investigated and the continuous tuning of the laser...

  1. Non-Debye heat capacity formula refined and applied to GaP, GaAs, GaSb, InP, InAs, and InSb

    R. Pässler

    2013-08-01

    Full Text Available Characteristic non-Debye behaviors of low-temperature heat capacities of GaP, GaAs, GaSb, InP, InAs, and InSb, which are manifested above all in form of non-monotonic behaviors (local maxima of the respective Cp(T/T3 curves in the cryogenic region, are described by means of a refined version of a recently proposed low-to-high-temperature interpolation formula of non-Debye type. Least-mean-square fittings of representative Cp(T data sets available for these materials from several sources show excellent agreements, from the liquid-helium region up to room temperature. The results of detailed calculations of the respective material-specific Debye temperature curves, ΘD(T, are represented in graphical form. The strong, non-monotonic variations of ΘD(T values confirm that it is impossible to provide reasonable numerical simulations of measured Cp(T dependences in terms of fixed Debye temperatures. We show that it is possible to describe in good approximation the complete Debye temperature curves, from the cryogenic region up to their definitive disappearance (dropping to 0 in the high temperature region, by a couple of unprecedented algebraic formulas. The task of constructing physically adequate prolongations of the low-temperature Cp(T curves up to melting points was strongly impeded by partly rather large differences (up to an order of 10 J/(K·mol between the high-temperature data sets presented in different research papers and/or data reviews. Physically plausible criteria are invoked, which enabled an a priori rejection of a series of obviously unrealistic high-temperature data sets. Residual uncertainties for GaAs and InAs could be overcome by re-evaluations of former enthalpy data on the basis of a novel set of properly specified four-parameter polynomial expressions applying to large regions, from moderately low temperatures up to melting points. Detailed analytical and numerical descriptions are given for the anharmonicity

  2. Model Legislation for GAAP and GASB.

    Bissell, George E.

    1987-01-01

    The use of generally accepted accounting principles (GAAP) by all state and local governments may require legislation. Findings from a survey of states to get data on current accounting and financial reporting practices are summarized. Model legislation to provide uniformity in accounting and reporting is presented. (MLF)

  3. GASB Statement No. 3 Guides Deposits, Investments.

    Barker, Linda A.

    1986-01-01

    Discusses an April 1986 Governmental Accounting Standards Board statement concerning disclosures of repurchase and reverse repurchase agreements. The statement tries to help financial statement users assess the risks a goverment entity takes when investing public funds. It is effective for financial statement periods ending after December 15,…

  4. Effect of pressure on some physical properties of gallium based semiconductors

    Vyas, P S; Thakore, B Y; Jani, A R; Gajjar, P N

    2012-01-01

    The gallium based semiconductor compounds are very useful materials for optical spectroscopy and optoelectronic applications, we have studied the effect of pressure on various physical properties like total energy, static bulk modulus, energy band gap at the point X on the Jones-zone face, pressure derivative of bulk modulus and equation of state of gallium based binary compounds GaSb, GaAs, GaP and GaN using pseudopotential theory beyond second order with our well established single parametric model potential. We have incorporated Nagy's static local field correction function to include exchange and correlation effects. The results are compared with those obtained using few other local field correction functions. The present results agree satisfactorily with available experimental and other such theoretical data confirming the application.

  5. Photoconduction spectroscopy of p-type GaSb films

    Shura, M.W., E-mail: Megersa.Shura@live.nmmu.ac.za [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Wagener, V.; Botha, J.R.; Wagener, M.C. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-05-15

    Excess carrier lifetimes (77 K) have been measured as function of the absorbed flux density in undoped p-type gallium antimonide films (GaSb/GaAs) using steady state photoconductivity measurements with the illumination wavelength of 1.1 {mu}m. Using the results from Hall effect measurements along with the relations describing the lifetimes of the excess minority carriers in the bulk of the films and at the surface, the theoretical values of the effective excess carrier lifetime in the materials were also calculated. Discrepancies between the experimental and theoretical results were described using a two-layer model, by considering the variation in the charge distribution within the layer due to the presence of surface states, as well as the band offset between the layer and the substrate. Theoretical modeling of the experimental result yields values of different parameters such as band bending at the surface, minimum value of Shockley-Read-Hall lifetime and maximum value of the surface recombination velocity.

  6. GASB 34 Financial Statements Are Easier With the Right Tools.

    Heinfeld, Gary; Arvizu, C. Christopher; Herrera, Michael L.

    2001-01-01

    Describes experience with certain tools and resources to help school business officials implement the Governmental Accounting Standards Board Statement 34. Focuses on Association of School Business Officials International's new Certificate of Excellence in Financial Reporting guidebook and financial-statement report-writer software called…

  7. Implementation Recommendations for School Districts. GASB Statement No. 34.

    Association of School Business Officials International, Reston, VA.

    Statement 34 is the most significant change in the history of governmental accounting. It is a dramatic change in the way school districts report and present financial information. This new reporting model affects every public-school organization that issues financial statements in conformity with generally accepted accounting principles (GAAP).…

  8. GASB's New Standard on Reporting Entity for School Districts.

    Harmer, W. Gary

    1991-01-01

    Explains the impact on school district financial reporting of the Governmental Accounting Standards Board Statement 14, "The Financial Reporting Entity." One of Statement 14's objectives is for financial report users to be able to distinguish between the primary government and its component units. (MLF)

  9. Photoconduction spectroscopy of p-type GaSb films

    Shura, M.W.; Wagener, V.; Botha, J.R.; Wagener, M.C.

    2012-01-01

    Excess carrier lifetimes (77 K) have been measured as function of the absorbed flux density in undoped p-type gallium antimonide films (GaSb/GaAs) using steady state photoconductivity measurements with the illumination wavelength of 1.1 μm. Using the results from Hall effect measurements along with the relations describing the lifetimes of the excess minority carriers in the bulk of the films and at the surface, the theoretical values of the effective excess carrier lifetime in the materials were also calculated. Discrepancies between the experimental and theoretical results were described using a two-layer model, by considering the variation in the charge distribution within the layer due to the presence of surface states, as well as the band offset between the layer and the substrate. Theoretical modeling of the experimental result yields values of different parameters such as band bending at the surface, minimum value of Shockley–Read–Hall lifetime and maximum value of the surface recombination velocity.

  10. Recombination Parameters for Antimonide-Based Semiconductors using RF Photoreflection Techniques

    Kumar, R.J.; Borrego, J.M.; Dutta, P.S.; Gutmann, R.J.; Wang, C.A.; Martinelli, R.U.; Nichols, G.

    2002-01-01

    RF photoreflection measurements and PC-1D simulations have been used to evaluate bulk and surface recombination parameters in antimonide-based materials. PC-1D is used to simulate the photoconductivity response of antimonide-based substrates and doubly-capped epitaxial layers and also to determine how to extract the recombination parameters using experimental results. Excellent agreement has been obtained with a first-order model and test structure simulation when Shockley-Reed-Hall (SRH) recombination is the bulk recombination process. When radiative, Auger and surface recombination are included, the simulation results show good agreement with the model. RF photoreflection measurements and simulations using PC-1D are compatible with a radiative recombination coefficient (B) of approximately 5 x 10 -11 cm 3 /s, Auger coefficient (C) ∼ 1.0 x 10 -28 cm 6 /s and surface recombination velocity (SRV) ∼ 600 cm/s for 0.50-0.55 eV doubly-capped InGaAsSb material with GaSb capping layers using the experimentally determined active layer doping of 2 x 10 17 cm -3 . Photon recycling, neglected in the analysis and simulations presented, will affect the extracted recombination parameters to some extent

  11. Write/erase time of nanoseconds in quantum dot based memory structures

    Nowozin, Tobias; Marent, Andreas; Geller, Martin; Bimberg, Dieter

    2008-01-01

    We have developed a novel charge-storage memory concept based on III-V semiconductor quantum dots (QDs) which has a number of fundamental advantages over conventional Si/SiO 2 floating gate memories (Flash): material-tunable and voltage-tunable barriers for improved intrinsic speed and/or storage time and high endurance. To investigate the potential of this new memory concept we have determined intrinsic write/erase times in memory structures based on InAs/GaAs and GaSb/GaAs QDs using capacitance-voltage spectroscopy. We measured a write time below 15 ns independent of the localization energy (i.e. the storage time) of the QDs. This write time is more than three orders of magnitude faster than in a Flash cell and already below the write time of a dynamic random access memory (DRAM). The erase time was determined to be 42 ns for InAs/GaAs QDs and 1.5 ms for GaSb/GaAs QDs for applied electric fields of 166 kV/cm and 206 kV/cm, respectively. From these results we derive an erase time of 1 ns in GaSb QDs for an electric field of 330 kV/cm

  12. Base

    Hjulmand, Lise-Lotte; Johansson, Christer

    2004-01-01

    BASE - Engelsk basisgrammatik er resultatet af Lise-Lotte Hjulmands grundige bearbejdning og omfattende revidering af Christer Johanssons Engelska basgrammatik. Grammatikken adskiller sig fra det svenske forlæg på en lang række punkter. Den er bl.a. tilpasset til et dansk publikum og det danske...

  13. ICP etching for InAs-based InAs/GaAsSb superlattice long wavelength infrared detectors

    Huang, Min; Chen, Jianxin; Xu, Jiajia; Wang, Fangfang; Xu, Zhicheng; He, Li

    2018-05-01

    In this work, we study and report the dry etching processes for InAs-based InAs/GaAsSb strain-free superlattice long wavelength infrared (LWIR) detectors. The proper etching parameters were first obtained through the parametric studies of Inductively Coupled Plasma (ICP) etching of both InAs and GaSb bulk materials in Cl2/N2 plasmas. Then an InAs-based InAs/GaAsSb superlattice LWIR detector with PπN structure was fabricated by using the optimized etching parameters. At 80 K, the detector exhibits a 100% cut-off wavelength of 12 μm and a responsivity of 1.5 A/W. Moreover, the dark current density of the device under a bias of -200 mV reaches 5.5 × 10-4 A/cm2, and the R0A is 15 Ω cm2. Our results pave the way towards InAs-based superlattice LWIR detectors with better performances.

  14. Molecular dynamics growth modeling of InAs1-xSbx-based type-II superlattice

    Ciani, Anthony J.; Grein, Christoph H.; Irick, Barry; Miao, Maosheng; Kioussis, Nicholas

    2017-09-01

    Type-II strained-layer superlattices (T2SL) based on InAs1-xSbx are a promising photovoltaic detector material technology for thermal imaging; however, Shockley-Read-Hall recombination and generation rates are still too high for thermal imagers based on InAs1-xSbx T2SL to reach their ideal performance. Molecular dynamics simulations using the Stillinger-Weber (SW) empirical potentials are a useful tool to study the growth of tetrahedral coordinated crystals and the nonequilibrium formation of defects within them, including the long-range effects of strain. SW potentials for the possible atomic interactions among {Ga, In, As, Sb} were developed by fitting to ab initio calculations of elastically distorted zinc blende and diamond unit cells. The SW potentials were tested against experimental observations of molecular beam epitaxial (MBE) growth and then used to simulate the MBE growth of InAs/InAs0.5Sb0.5 T2SL on GaSb substrates over a range of processes parameters. The simulations showed and helped to explain Sb cross-incorporation into the InAs T2SL layers, Sb segregation within the InAsSb layers, and identified medium-range defect clusters involving interstitials and their induction of interstitial-vacancy pairs. Defect formation was also found to be affected by growth temperature and flux stoichiometry.

  15. Small-pixel long wavelength infrared focal plane arrays based on InAs/GaSb Type-II superlattice

    Han, Xi; Jiang, Dongwei; Wang, Guowei; Hao, Hongyue; Sun, Yaoyao; Jiang, Zhi; Lv, Yuexi; Guo, Chunyan; Xu, Yingqiang; Niu, Zhichuan

    2018-03-01

    The paper reports a 640 × 512 long wavelength infrared focal plane arrays (FPAs) with 15 × 15 μm2 pixels pitch based on the type II InAs/GaSb superlattice. Material grown on a 3 in. GaSb substrate exhibits a 50% cutoff wavelength of 10.2 μm across the entire wafer. The peak quantum efficiency of the detector reaches 28% at 9.1 μm without anti-reflecting coating. Maximal resistance-area products of 8.95 Ω·cm2 at 77 K and 24.4 Ω·cm2 at 45 K are achieved in a single element device indicating that the generation-recombination and tunneling mechanisms dominate the device dark current, respectively. The peak Johnson Detectivity reaches 9.66 × 1011 cm Hz1/2/W at 9.1 μm with the bias voltage of 80 mV. In the whole zone, the operability and non-uniformity for the responsivity are 97.74% and 6.41% respectively. The average noise equivalent temperature difference of 31.9 mK at 77 K is achieved with an integration time of 0.5 ms, a 300 K background and f/2 optics.

  16. Single-mode electrically pumped GaSb-based VCSELs emitting continuous-wave at 2.4 and 2.6 μm

    Bachmann, Alexander; Arafin, Shamsul; Kashani-Shirazi, Kaveh

    2009-01-01

    Vertical-cavity surface-emitting lasers (VCSELs) are perfect light sources for spectroscopic applications, where properties such as continuous-wave (cw) operation, single-mode emission, high lifetime and often low power consumption are crucial. For applications such as tunable diode laser absorption spectroscopy (TDLAS), there is a growing interest in laser devices emitting in the near- to mid-infrared wavelength range, where many environmentally and technologically important gases show strong absorption lines. The (AlGaIn)(AsSb) material system based on GaSb is the material of choice for covering the 2.0-3.3 μm range. In this paper, we report on electrically pumped single-mode VCSELs with emission wavelengths of 2.4 and 2.6 μm, operating cw at room temperature and beyond. By (electro-) thermal tuning, the emission wavelength can be tuned mode-hop free over a range of several nanometers. In addition, low threshold currents of several milliamperes promise mobile application. In the devices, a structured buried tunnel junction with subsequent overgrowth has been used in order to achieve efficient current confinement, reduced optical losses and increased electrical conductivity. Furthermore, strong optical confinement is introduced in the lasers due to laterally differing cavity lengths.

  17. Role of the acid-base properties of gallium-antimony oxide catalyst in oxidative ammonolysis of propane to acrylonitrile (AN)

    Osipova, Z.G.; Sokolovskii, V.D.

    1979-07-01

    The role of the acid-base properties of gallium-antimony oxide catalyst in oxidative ammonolysis of propane to acrylonitrile (AN) was studied in a differential flow reactor at 550/sup 0/C, with the reaction mixture containing 5 3< by vol propane, 6 3< ammonia, and 18.6Vertical Bar3< oxygen diluted in helium, over ebulliated beds of a 5Vertical Bar3< Ga/Sb or a 1:3:1.5:1 Ga/Sb/Ni/P catalysts, the basicity of which was varied by adding 5 mole Vertical Bar3< of an alkaline earth metal (added as the nitrate and calcined). Both the rate of propane conversion and that of AN formation increased with increasing concentration of the basic sites (determined by back titration with benzoic acid) on both types of the catalysts and linearly correlated with the amount of nitrous oxide desorbed from the catalysts after the reaction. The presence of ammonia in the reaction mixture increased the activity and selectivity of the catalysts and the concentration of the active basic sites. Apparently, the reaction rate is limited by proton abstraction from a propane molecule with the formation of a carbanion stabilized on alkaline-earth metal cations. The rate-determining proton abstraction occurs on nucleophile basic sites, formed by dissociative adsorption of ammonia to form species such as NH, NH/sub 2/, and HNO, which are then oxidized to N/sub 2/ and N/sub 2/O.

  18. GaSb-based single-mode distributed feedback lasers for sensing (Conference Presentation)

    Gupta, James A.; Bezinger, Andrew; Lapointe, Jean; Poitras, Daniel; Aers, Geof C.

    2017-02-01

    GaSb-based tunable single-mode diode lasers can enable rapid, highly-selective and highly-sensitive absorption spectroscopy systems for gas sensing. In this work, single-mode distributed feedback (DFB) laser diodes were developed for the detection of various trace gases in the 2-3.3um range, including CO2, CO, HF, H2S, H2O and CH4. The lasers were fabricated using an index-coupled grating process without epitaxial regrowth, making the process significantly less expensive than conventional DFB fabrication. The devices are based on InGaAsSb/AlGaAsSb separate confinement heterostructures grown on GaSb by molecular beam epitaxy. DFB lasers were produced using a two step etch process. Narrow ridge waveguides were first defined by optical lithography and etched into the semiconductor. Lateral gratings were then defined on both sides of the ridge using electron-beam lithography and etched to produce the index-grating. Effective index modeling was used to optimize the ridge width, etch depths and the grating pitch to ensure single-lateral-mode operation and adequate coupling strength. The effective index method was further used to simulate the DFB laser emission spectrum, based on a transfer matrix model for light transmission through the periodic structure. The fabricated lasers exhibit single-mode operation which is tunable through the absorption features of the various target gases by adjustment of the drive current. In addition to the established open-path sensing applications, these devices have great potential for optoelectronic integrated gas sensors, making use of integrated photodetectors and possibly on-chip Si photonics waveguide structures.

  19. Effect of updated data base and improved analysis on performance of radioisotope thermophotovoltaic converter

    Schock, A.; Or, C.T.

    1996-01-01

    Previous analyses of RTPV space power systems published by the authors were based on a number of approximations employed to permit early dissemination of preliminary results pending availability of fuller experimental data need3d to conduct more rigorous analyses. Among those approximations were: (1) the use of limited test data and optimistic projections of the spectral transmissivity of the RTPV's selective IR filters and of the spectral quantum efficiency of the GaSb PV cells; (2) the use of theoretical formulas instead of experimental measurements of the PV cell's open-circuit voltage, fill factor, and optimum voltage instead of its measured current-voltage characteristics; (3) rough estimates of the TPV converter's active-area fraction instead of computed values based on detailed designs; (4) inadequate accounting for the effect of radiation reflected by the IR filter and absorbed by the emitter in reducing the generator's required heat input; and (5) omission of the shadowing effect and ohmic losses caused by the PV cell's grid lines. The above-listed shortcomings of the previously published analyses are addressed in the present paper, which describes revised analyses based on recently obtained experimental data of IR filter reflectivities and PV cell quantum efficiencies and current-voltage characteristic, measured by EDTEK under an OSC-initiated subcontract to its ongoing DOE contract. Their test results show that EDTEK has been eminently successful in improving the reflectivities of the IR filters and in reproducing the quantum efficiencies of Boeing's best PV cells, but their initial (Dec-95) PV cell fell far short of matching the open-circuit voltages and fill factors predicted by theory

  20. Inductively coupled plasma etching of III-V antimonides in BCl3/SiCl4 etch chemistry

    Swaminathan, K.; Janardhanan, P.E.; Sulima, O.V.

    2008-01-01

    Inductively coupled plasma etching of GaSb using BCl 3 /SiCl 4 etch chemistry has been investigated. The etch rates were studied as a function of bias power, inductively coupled plasma source power, plasma chemistry and chamber pressure. The etched surfaces remain smooth and stoichiometric over the entire range of plasma conditions investigated. The knowledge gained in etching GaSb was applied to etching AlGaAsSb and InGaAsSb in order to fabricate heterojunction phototransistors. As expected, InGaAsSb etch rate was much lower compared to the corresponding value for GaSb, mainly due to the relatively low volatility of indium chlorides. For a wide range of plasma conditions, the selectivity between GaSb and AlGaAsSb was close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-infrared laser diodes. The surface roughness and the etch profile were examined for the etched GaSb, AlGaAsSb and InGaAsSb samples using scanning electron microscope. The high etch rates achieved (∼ 4 μm/min) facilitated deep etching of GaSb. A single layer, soft mask (AZ-4903 photoresist) was used to etch GaSb, with etch depth ∼ 90 μm. The deep dry etching of GaSb has many important applications including etching substrate windows for backside-illuminated photodetectors for the mid-infrared wavelength range

  1. Inductively coupled plasma etching of III-V antimonides in BCl{sub 3}/SiCl{sub 4} etch chemistry

    Swaminathan, K. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)], E-mail: swaminak@ece.osu.edu; Janardhanan, P.E.; Sulima, O.V. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)

    2008-10-01

    Inductively coupled plasma etching of GaSb using BCl{sub 3}/SiCl{sub 4} etch chemistry has been investigated. The etch rates were studied as a function of bias power, inductively coupled plasma source power, plasma chemistry and chamber pressure. The etched surfaces remain smooth and stoichiometric over the entire range of plasma conditions investigated. The knowledge gained in etching GaSb was applied to etching AlGaAsSb and InGaAsSb in order to fabricate heterojunction phototransistors. As expected, InGaAsSb etch rate was much lower compared to the corresponding value for GaSb, mainly due to the relatively low volatility of indium chlorides. For a wide range of plasma conditions, the selectivity between GaSb and AlGaAsSb was close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-infrared laser diodes. The surface roughness and the etch profile were examined for the etched GaSb, AlGaAsSb and InGaAsSb samples using scanning electron microscope. The high etch rates achieved ({approx} 4 {mu}m/min) facilitated deep etching of GaSb. A single layer, soft mask (AZ-4903 photoresist) was used to etch GaSb, with etch depth {approx} 90 {mu}m. The deep dry etching of GaSb has many important applications including etching substrate windows for backside-illuminated photodetectors for the mid-infrared wavelength range.

  2. Financial Reporting under GASB Statement No. 34 and ASBO International Certificate of Excellence Financial Reporting.

    Heinfeld, Gary

    This guide presents a financial model that affects all governmental entities that issue financial statements in conformity with Generally Accepted Accounting Principles (GAAP). The model was prepared to provide school business officials specific examples of school system financial-statement presentations. The guide is divided into six chapters.…

  3. Te-high doping of GaSb grown in ionized hydrogen atmosphere

    Štěpánek, Bedřich; Šestáková, Věra; Šesták, Jaroslav

    1999-01-01

    Roč. 50, 5/7 (1999), s. 5-7 ISSN 1335-3632. [Development of Materials Science in Research and Education - DMS -RE 1998 /8./. Zlenice, 08.09.1998-10.09.1998] Subject RIV: BM - Solid Matter Physics ; Magnetism

  4. Investigation of InAs/GaSb-based superlattices by diffraction methods

    Ashuach, Y.; Kauffmann, Y.; Lakin, E. [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Zolotoyabko, E., E-mail: zloto@tx.technion.ac.i [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Grossman, S.; Klin, O.; Weiss, E. [SCD, SemiConductor Devices, P. O. Box 2250, Haifa 31021 (Israel)

    2010-02-15

    We use high-resolution X-ray diffraction and high-resolution transmission electron microscopy in order to study the strain state, atomic intermixing and layer thicknesses in the MBE-grown GaSb/InSb/InAs/InSb superlattices. Simple and fast metrology procedure is developed, which allows us to obtain the most important technological parameters, such as the thicknesses of the GaSb, InAs and ultra-thin InSb sub-layers, the superlattice period and the fraction of atomic substitutions in the InSb sub-layers.

  5. Molecular Beam Epitaxy on Gas Cluster Ion Beam Prepared GaSb Substrates: Towards Improved Surfaces and Interfaces

    Krishnaswami, Kannan; Vangala, Shivashankar R; Dauplaise, Helen M; Allen, Lisa P; Dallas, Gordon; Bakken, Daniel; Bliss, David F; Goodhue, WIlliam D

    2007-01-01

    ... at temperatures ranging 530 degrees C to 560 degrees C. Cross-sectional transmission electron microscopy of molecular beam epitaxy grown GaSb/AlGaSb layers showed that the HBr-GCIB surface produced a smooth dislocation-free substrate-to-epi transition...

  6. Phase change cellular automata modeling of GeTe, GaSb and SnSe stacked chalcogenide films

    Mihai, C.; Velea, A.

    2018-06-01

    Data storage needs are increasing at a rapid pace across all economic sectors, so the need for new memory technologies with adequate capabilities is also high. Phase change memories (PCMs) are a leading contender in the emerging race for non-volatile memories due to their fast operation speed, high scalability, good reliability and low power consumption. However, in order to meet the present and future storage demands, PCM technologies must further increase the storage density. Here, we employ a probabilistic cellular automata approach to explore the multi-step threshold switching from the reset (off) to the set (on) state in chalcogenide stacked structures. Simulations have shown that in order to obtain multi-step switching with high contrast among different resistance states, the stacked structure needs to contain materials with a large difference among their crystallization temperatures and careful tuning of strata thicknesses. The crystallization dynamics can be controlled through the external energy pulses applied to the system, in such a way that a balance between nucleation and growth in phase change behavior can be achieved, optimized for PCMs.

  7. Phase 2 - GASB Statement 34 compliance : development of a fixed asset (infrastructure) for the Alabama Department of Transportation

    2003-05-01

    The Alabama Department of Transportation (ALDOT) Bureau of Materials and Tests has been working with the University of Alabama's Management Information Systems Department to provide a tool for road maintenance and optimization associated funding. Spe...

  8. GASB Statement 34 compliance : development of a fixed asset (infrastructure) MIS, Phase 1 for the Alabama Department of Transportation

    2002-01-02

    This project defined the scope, goals, and high-level requirements for the Alabama Department of Transportation's Asset Management System, so that it will comply with the General Accounting Standards Board policy 34. The system will provide a network...

  9. Device design of GaSb/CdS thin film thermal photovoltaic solar cells%基于GaSb/CdS薄膜热光伏电池的器件设计∗

    吴限量; 张德贤; 蔡宏琨; 周严; 倪牮; 张建军

    2015-01-01

    基于GaSb薄膜热光伏器件是降低热光伏系统成本的有效途径之一,本文主要针对GaSb/CdS薄膜热光伏器件结构进行理论分析.采用AFORS-HET软件进行模拟仿真,分析GaSb和CdS两种材料各自的缺陷态密度、界面态对电池性能的影响.根据软件模拟可以得知,吸收层GaSb的缺陷态密度以及GaSb与CdS之间的界面态密度是影响电池性能的重要因素.当GaSb缺陷态增加时,主要影响电池的填充因子,电池效率明显下降.而作为窗口层的CdS缺陷态密度对电池性能影响不明显,当CdS缺陷态密度上升4个数量级时,电池效率仅下降0.11%.%Enthusiasm in the research of thermo-photovoltaic (TPV) cells has been aroused because the low bandwidth semi-conductors of III-V family are coming into use. GaSb, as a member of III-V family, has many merits such as high absorption coeffcient, and low band gap of 0.725 eV at 300 K etc.. At present thermo-photovoltaic cells are usually based on GaSb wafer, and it can be manufactured by the vertical Bridgeman method. Thermo-photovoltaic cell based on GaSb films is one of the effective ways to reduce the cost of the thermo-photovoltaic system. GaSb polycrystalline films can be grown by physical vapor deposition (PVD) which has advantages in using fewer materials and energy, and also in doing little harm to the environment. Because of residual acceptor defects VGaGaSb, GaSb thin film is usually of p-type semiconductor. So we should find n-type semiconductor material to form pn junction. We choose CdS as the emission layer of a cell structure. CdS belongs to n-type semiconductor with a narrow band gap of 2.4 eV and high light transmissivity. CdS thin film grown by chemical bath deposition (CBD) has passivation properties for GaSb. CdS layers can remove native oxides from GaSb surface and reduce the surface recombination velocity of GaSb. This paper focuses on theoretical analysis of GaSb/CdS thin film photovoltaic

  10. Impairment no setor público: particularidades das normas nacionais e internacionais Impairment in the public sector: particularities of Brazilian and international standards

    Luiz Nelson Guedes de Carvalho

    2010-08-01

    Full Text Available O impairment no setor público tem sido pouco discutido no meio acadêmico. Os órgãos normatizadores têm publicado pronunciamentos sobre o assunto, enquanto muitas dúvidas surgem e permanecem sem resposta. Diante disso, este artigo analisa as particularidades de normas nacionais e internacionais balizadoras do impairment no setor público: o Gasb 42, os Ipsas 21 e 26 e a NBC T 16.10. Foram analisados aspectos relacionados ao conceito de impairment, à periodicidade de aplicação do teste, para quais ativos deve ser aplicado e o processo de reconhecimento, mensuração e evidenciação da perda por impairment. As principais divergências entre os pronunciamentos são: o Gasb 42 está baseado em princípios e não em regras; os critérios utilizados pelo Gasb 42 para cálculo do fair value são semelhantes àqueles usados pelos Ipsas 21 e 26 para cálculo do valor em uso; o valor de reposição é usado para cálculo do fair value no Gasb 42 e o valor de saída nos Ipsas; apenas o Ipsas 26 utiliza a figura da unidade geradora de caixa; o Gasb 42 não admite a reversão da perda por impairment e os Ipsas não se aplicam a bens reavaliados. Apesar da NBC T 16.10 já estar em vigor no Brasil, todos os ativos públicos e a depreciação precisam ser reconhecidos e mensurados antes da aplicação dessa normaLittle discussion on impairment in the public sector has occurred in the academic context. Standardizing bodies have published pronouncements on this issue, but many doubts arise and remain unanswered. This article analyzes the particularities of Brazilian and international standards guiding impairment in the public sector: Gasb 42, Ipsas 21 and 26 and NBC T 16.10. The aspects analyzed were related to the impairment concept, the periodicity of applying the test, what assets it should be applied to and the recognition, measurement and disclosure process of impairment loss. The main divergences between the pronouncements are: Gasb 42 is based on

  11. Lock-in amplifier- based rotating- analyzer spectroscopic ellipsometer with micro-controlled angular frequency

    Flores C, J.M.; Nunez O, O.F.; Rodriguez P, G.; Lastras M, A.; Lastras M, L.F. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi (Mexico)

    2005-07-01

    We report on the development of a full operational rotating analyzer spectroscopic ellipsometer. This instrument employs a phase-sensitive amplifier to process the optical signal as an alternative to Fast Fourier Transform analysis. We describe electronic hardware designed to stabilize the rotation frequency of the analyzer prism as well as to drive the device for the positioning of the polarizer prism azimuth. The ellipsometer allows for dielectric function measurement in the energy range from 1.7-5.5 eV, in both ambient air and Ultra High Vacuum (UHV). UHV measurements can be carried out at a temperature as low as 150 K. To evaluate the ellipsometer performance we present results of the determination of the complex dielectric function of a number of semiconductors, namely, GaSb, GaAs, InGaAs, CdTe and CdHgTe. (Author)

  12. Financial Condition Analysis In Municipalities: A Case Of Turkey

    ÖZKUL, Fatma; ALKAN, Betül Şeyma

    2017-01-01

    This study included the analysis of prepared comprehensive financial statements with the transitionto accrual-based accounting system from cash-based accounting system in the public institutionsin 2006. In Turkey, there is no specific method developed to the goals of public institutions. GASB 1Reporting Model, which is a model developed in the USA, and is not yet used in Turkey, has been appliedby taking financial statements data of the Istanbul Metropolitan Municipality. The study was carrie...

  13. Financial condition analysis ın municipalities: a case of turkey

    ÖZKUL, Fatma; ALKAN, Betül Şeyma

    2017-01-01

    This study included the analysis of prepared comprehensive financial statements with the transition to accrual-based accounting system from cash-based accounting system in the public institutions in 2006. In Turkey, there is no specific method developed to the goals of public institutions. GASB 1 Reporting Model, which is a model developed in the USA, and is not yet used in Turkey, has been applied by taking financial statements data of the Istanbul Metropolitan Municipality. ...

  14. Room-temperature operation of a 2.25 μm electrically pumped laser fabricated on a silicon substrate

    Rodriguez, J. B.; Cerutti, L.; Grech, P.; Tournie, E.

    2009-01-01

    We report on a GaSb-based type-I laser structure grown by molecular beam epitaxy on a (001) silicon substrate. A thin AlSb nucleation layer followed by a 1 μm thick GaSb buffer layer was used to accommodate the very large lattice mismatch existing with the silicon substrate. Processed devices with mesa geometry exhibited laser operation in pulsed mode with a duty cycle up to 10% at room temperature

  15. Advantages and disadvantages of sulfur passivation of InAs/GaSb superlattice waveguide photodiodes

    Hoffmann, J; Lehnert, T; Hoffmann, D; Fouckhardt, H

    2009-01-01

    In this work, the influence of ammonium sulfide (NH 4 ) 2 S passivation on waveguide based mid-infrared InAs/GaSb superlattice photodetectors (2–5 µm wavelength) has been studied. The current–voltage characteristics for reverse as well as for forward bias of passivated samples have been examined. The advantages of this have been the reduction of the reverse leakage current and the increase of zero bias resistance. As a disadvantage the decrease of the photoresponsivity after sulfur passivation has been found. Furthermore, it has been observed that the passivation solution does not only passivate the surface of GaSb, but it also reacts with entire GaSb layers and can destroy the devices

  16. Lotus Base

    Mun, Terry; Bachmann, Asger; Gupta, Vikas

    2016-01-01

    exploration of Lotus genomic and transcriptomic data. Equally important are user-friendly in-browser tools designed for data visualization and interpretation. Here, we present Lotus Base, which opens to the research community a large, established LORE1 insertion mutant population containing an excess of 120...... such data, allowing users to construct, visualize, and annotate co-expression gene networks. Lotus Base takes advantage of modern advances in browser technology to deliver powerful data interpretation for biologists. Its modular construction and publicly available application programming interface enable...... developers to tap into the wealth of integrated Lotus data. Lotus Base is freely accessible at: https://lotus.au.dk....

  17. Touch BASE

    Antonella Del Rosso

    2015-01-01

    In a recent Nature article (see here), the BASE collaboration reported the most precise comparison of the charge-to-mass ratio of the proton to its antimatter equivalent, the antiproton. This result is just the beginning and many more challenges lie ahead.   CERN's AD Hall, where the BASE experiment is set-up. The Baryon Antibaryon Symmetry Experiment (BASE) was approved in June 2013 and was ready to take data in August 2014. During these 14 months, the BASE collaboration worked hard to set up its four cryogenic Penning traps, which are the heart of the whole experiment. As their name indicates, these magnetic devices are used to trap antiparticles – antiprotons coming from the Antiproton Decelerator – and particles of matter – negative hydrogen ions produced in the system by interaction with a degrader that slows the antiprotons down, allowing scientists to perform their measurements. “We had very little time to set up the wh...

  18. Spectral and spatial resolving of photoelectric property of femtosecond laser drilled holes of GaSb(1-x)Bi(x).

    Pan, C B; Zha, F X; Song, Y X; Shao, J; Dai, Y; Chen, X R; Ye, J Y; Wang, S M

    2015-07-15

    Femtosecond laser drilled holes of GaSbBi were characterized by the joint measurements of photoconductivity (PC) spectroscopy and laser-beam-induced current (LBIC) mapping. The excitation light in PC was focused down to 60 μm presenting the spectral information of local electronic property of individual holes. A redshift of energy band edge of about 6-8 meV was observed by the PC measurement when the excitation light irradiated on the laser drilled holes. The spatial resolving of photoelectric property was achieved by the LBIC mapping which shows "pseudo-holes" with much larger dimensions than the geometric sizes of the holes. The reduced LBIC current with the pseudo-holes is associated with the redshift effect indicating that the electronic property of the rim areas of the holes is modified by the femtosecond laser drilling.

  19. GaSb and GaSb/AlSb Superlattice Buffer Layers for High-Quality Photodiodes Grown on Commercial GaAs and Si Substrates

    Gutiérrez, M.; Lloret, F.; Jurczak, P.; Wu, J.; Liu, H. Y.; Araújo, D.

    2018-05-01

    The objective of this work is the integration of InGaAs/GaSb/GaAs heterostructures, with high indium content, on GaAs and Si commercial wafers. The design of an interfacial misfit dislocation array, either on GaAs or Si substrates, allowed growth of strain-free devices. The growth of purposely designed superlattices with their active region free of extended defects on both GaAs and Si substrates is demonstrated. Transmission electron microscopy technique is used for the structural characterization and plastic relaxation study. In the first case, on GaAs substrates, the presence of dopants was demonstrated to reduce several times the threading dislocation density through a strain-hardening mechanism avoiding dislocation interactions, while in the second case, on Si substrates, similar reduction of dislocation interactions is obtained using an AlSb/GaSb superlattice. The latter is shown to redistribute spatially the interfacial misfit dislocation array to reduce dislocation interactions.

  20. Phase transformations in ion-mixed metastable (GaSb)1/sub 1 -x/(Ge2)/sub x/ semiconducting alloys

    Cadien, K.C.; Muddle, B.C.; Greene, J.E.

    1984-01-01

    Low energy (75--175 eV) Ar + ion bombardment during film deposition has been used to produce well-mixed amorphous GaSb/Ge mixtures which, when annealed, transform first to single phase polycrystalline metastable (GaSb)/sub 1-x/(Ge 2 )/sub x/ alloys before eventually transforming to the equilibrium two-phase state. At 500 0 C, for example, the annealing time t/sub a/ required for the amorphous to crystalline metastable (ACM) transformation was approx.10 min, while t/sub a/ for the crystalline metastable to equilibrium (CME) transformation was >6 h. The exothermic enthalpy of crystallization and the onset temperature of the ACM transition were determined as a function of alloy composition using differential thermal analysis. The thermodynamic data was then used to calculate the surface energy per unit area sigma of the amorphous/metastable-crystal interface. sigma was found to exhibit a minimum between x = 0.3 and 0.4. The driving energy for the transition from the crystalline metastable state to the equilibrium two-phase state was of the order of 0.12 kJ cm -3 while the activation barrier was approx.19 kJ cm -3 . Thus, the metastable alloys, which had average grain sizes of 100--200 nm and a lattice constant which varied linearly with x, exhibited good thermal and temporal stability

  1. Atmospheric pressure-MOVPE growth of GaSb/GaAs quantum dots

    Tile, Ngcali; Ahia, Chinedu C.; Olivier, Jaco; Botha, Johannes Reinhardt

    2018-04-01

    This study focuses on the growth of GaSb/GaAs quantum dots (QD) using an atmospheric pressure MOVPE system. For the best uncapped dots, the average dot height, base diameter and density are 5 nm, 45 nm and 4.5×1010 cm-2, respectively. Capping of GaSb QDs at high temperatures caused flattening and formation of thin inhomogeneous GaSb layer inside GaAs resulting in no obvious QD PL peak. Capping at low temperatures lead to the formation of dot-like features and a wetting layer (WL) with distinct PL peaks for QD and WL at 1097 nm and 983 nm respectively. Some of the dot-like features had voids. An increase in excitation power caused the QD and WL peaks to shift to higher energies. This is attributed to electrostatic band bending leading to triangular potential wells, typical of type-II alignment between GaAs and strained GaSb. Variable temperature PL measurements of the QD sample showed the decrease in the intensity of the WL peak to be faster than that of the QD peak as the temperature increased.

  2. Fragmentation based

    Shashank Srivastava

    2014-01-01

    Gaining the understanding of mobile agent architecture and the security concerns, in this paper, we proposed a security protocol which addresses security with mitigated computational cost. The protocol is a combination of self decryption, co-operation and obfuscation technique. To circumvent the risk of malicious code execution in attacking environment, we have proposed fragmentation based encryption technique. Our encryption technique suits the general mobile agent size and provides hard and thorny obfuscation increasing attacker’s challenge on the same plane providing better performance with respect to computational cost as compared to existing AES encryption.

  3. 77 FR 12340 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Order Granting...

    2012-02-29

    ... of the GASB to establish standards of financial accounting and reporting applicable to state and... accepted accounting principles by the GASB.\\14\\ \\12\\ See 15 U.S.C. 77s(g)(1). \\13\\ See 15 U.S.C. 77s(g)(3... that, under the proposed rule, many diverse end users of GASB's accounting and financial reporting...

  4. Gaining Insight into an Organization's Fixed Assets.

    Hardy, Elisabet

    2003-01-01

    Discusses issues related to school district implementation of June 2001 Government Accounting Standards Board (GASB) Statement 34 designed to change how schools report fixed assets. Includes planning for GASB implementation, conducting fixed-asset inventories, and making time for GASB reporting. (PKP)

  5. Fuzzy knowledge bases integration based on ontology

    Ternovoy, Maksym; Shtogrina, Olena

    2012-01-01

    the paper describes the approach for fuzzy knowledge bases integration with the usage of ontology. This approach is based on metadata-base usage for integration of different knowledge bases with common ontology. The design process of metadata-base is described.

  6. Foundation: Transforming data bases into knowledge bases

    Purves, R. B.; Carnes, James R.; Cutts, Dannie E.

    1987-01-01

    One approach to transforming information stored in relational data bases into knowledge based representations and back again is described. This system, called Foundation, allows knowledge bases to take advantage of vast amounts of pre-existing data. A benefit of this approach is inspection, and even population, of data bases through an intelligent knowledge-based front-end.

  7. Paper based electronics platform

    Nassar, Joanna Mohammad; Sevilla, Galo Andres Torres; Hussain, Muhammad Mustafa

    2017-01-01

    A flexible and non-functionalized low cost paper-based electronic system platform fabricated from common paper, such as paper based sensors, and methods of producing paper based sensors, and methods of sensing using the paper based sensors

  8. Cost estimate of electricity produced by TPV

    Palfinger, Günther; Bitnar, Bernd; Durisch, Wilhelm; Mayor, Jean-Claude; Grützmacher, Detlev; Gobrecht, Jens

    2003-05-01

    A crucial parameter for the market penetration of TPV is its electricity production cost. In this work a detailed cost estimate is performed for a Si photocell based TPV system, which was developed for electrically self-powered operation of a domestic heating system. The results are compared to a rough estimate of cost of electricity for a projected GaSb based system. For the calculation of the price of electricity, a lifetime of 20 years, an interest rate of 4.25% per year and maintenance costs of 1% of the investment are presumed. To determine the production cost of TPV systems with a power of 12-20 kW, the costs of the TPV components and 100 EUR kW-1el,peak for assembly and miscellaneous were estimated. Alternatively, the system cost for the GaSb system was derived from the cost of the photocells and from the assumption that they account for 35% of the total system cost. The calculation was done for four different TPV scenarios which include a Si based prototype system with existing technology (etasys = 1.0%), leading to 3000 EUR kW-1el,peak, an optimized Si based system using conventional, available technology (etasys = 1.5%), leading to 900 EUR kW-1el,peak, a further improved system with future technology (etasys = 5%), leading to 340 EUR kW-1el,peak and a GaSb based system (etasys = 12.3% with recuperator), leading to 1900 EUR kW-1el,peak. Thus, prices of electricity from 6 to 25 EURcents kWh-1el (including gas of about 3.5 EURcents kWh-1) were calculated and compared with those of fuel cells (31 EURcents kWh-1) and gas engines (23 EURcents kWh-1).

  9. The physics data base

    Gault, F.D.

    1984-01-01

    The physics data base is introduced along with its associated data base management system. The emphasis is on data and their use and a classification of data and of data bases is developed to distinguish compilation organizations. The characteristics of these organizations are examined briefly and the long term consequences of the physics data base discussed. (orig.)

  10. Solid Base Catalysis

    Ono, Yoshio

    2011-01-01

    The importance of solid base catalysts has come to be recognized for their environmentally benign qualities, and much significant progress has been made over the past two decades in catalytic materials and solid base-catalyzed reactions. The book is focused on the solid base. Because of the advantages over liquid bases, the use of solid base catalysts in organic synthesis is expanding. Solid bases are easier to dispose than liquid bases, separation and recovery of products, catalysts and solvents are less difficult, and they are non-corrosive. Furthermore, base-catalyzed reactions can be performed without using solvents and even in the gas phase, opening up more possibilities for discovering novel reaction systems. Using numerous examples, the present volume describes the remarkable role solid base catalysis can play, given the ever increasing worldwide importance of "green" chemistry. The reader will obtain an overall view of solid base catalysis and gain insight into the versatility of the reactions to whic...

  11. Fabrication of metallic nanomasks by transfer of self-organized nanodot patterns from semiconductor material into thin metallic layers

    Bobek, T.; Kurz, H.

    2007-01-01

    The basic understanding of the formation of highly regular nanostructures during ion erosion of amorphous GaSb layers is revised. The essential physical parameters for the formation of the highly regular dot pattern are discussed. Numerical modelling based on the stabilized isotropic Kuramoto-Sivashinsky equation is presented and discussed. The experimental part of this contribution presents the successful pattern transfer into metallic buried thin layers as well as into Silicon underlayers. The critical conditions for this transfer technique are discussed. Application potential of using this self-organization scheme for the generation of highly regular patterns in ferromagnetic metal layers as well as in crystalline silicon is estimated

  12. Beyond Zero Based Budgeting.

    Ogden, Daniel M., Jr.

    1978-01-01

    Suggests that the most practical budgeting system for most managers is a formalized combination of incremental and zero-based analysis because little can be learned about most programs from an annual zero-based budget. (Author/IRT)

  13. VectorBase

    U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...

  14. Mobile Inquiry Based Learning

    Specht, Marcus

    2012-01-01

    Specht, M. (2012, 8 November). Mobile Inquiry Based Learning. Presentation given at the Workshop "Mobile inquiry-based learning" at the Mobile Learning Day 2012 at the Fernuniversität Hagen, Hagen, Germany.

  15. Microbead agglutination based assays

    Kodzius, Rimantas; Castro, David; Foulds, Ian G.; Parameswaran, Ash M.; Sumanpreet, K. Chhina

    2013-01-01

    We report a simple and rapid room temperature assay for point-of-care (POC) testing that is based on specific agglutination. Agglutination tests are based on aggregation of microbeads in the presence of a specific analyte thus enabling

  16. Carbon Based Nanotechnology: Review

    Srivastava, Deepak; Saini, Subhash (Technical Monitor)

    1999-01-01

    This presentation reviews publicly available information related to carbon based nanotechnology. Topics covered include nanomechanics, carbon based electronics, nanodevice/materials applications, nanotube motors, nano-lithography and H2O storage in nanotubes.

  17. The ground based plan

    1989-01-01

    The paper presents a report of ''The Ground Based Plan'' of the United Kingdom Science and Engineering Research Council. The ground based plan is a plan for research in astronomy and planetary science by ground based techniques. The contents of the report contains a description of:- the scientific objectives and technical requirements (the basis for the Plan), the present organisation and funding for the ground based programme, the Plan, the main scientific features and the further objectives of the Plan. (U.K.)

  18. Stolen Base Physics

    Kagan, David

    2013-01-01

    Few plays in baseball are as consistently close and exciting as the stolen base. While there are several studies of sprinting, the art of base stealing is much more nuanced. This article describes the motion of the base-stealing runner using a very basic kinematic model. The model will be compared to some data from a Major League game. The…

  19. Convergent Filter Bases

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  20. Cholinesterase-based biosensors.

    Štěpánková, Šárka; Vorčáková, Katarína

    2016-01-01

    Recently, cholinesterase-based biosensors are widely used for assaying anticholinergic compounds. Primarily biosensors based on enzyme inhibition are useful analytical tools for fast screening of inhibitors, such as organophosphates and carbamates. The present review is aimed at compilation of the most important facts about cholinesterase based biosensors, types of physico-chemical transduction, immobilization strategies and practical applications.

  1. ARAC terrain data base

    Walker, H.

    1982-11-01

    A terrain data base covering the continental United States at 500-meter resolution has been generated. Its function is to provide terrain data for input to mesoscale atmospheric models that are used as part of the Atmospheric Release Advisory Capability at Lawrence Livermore Laboratory (LLNL). The structure of the data base as it exists on the LLNL computer system is described. The data base has been written to tapes for transfer to other systems and the format of these tapes is also described

  2. Base Station Performance Model

    Walsh, Barbara; Farrell, Ronan

    2005-01-01

    At present the testing of power amplifiers within base station transmitters is limited to testing at component level as opposed to testing at the system level. While the detection of catastrophic failure is possible, that of performance degradation is not. This paper proposes a base station model with respect to transmitter output power with the aim of introducing system level monitoring of the power amplifier behaviour within the base station. Our model reflects the expe...

  3. Value-based pricing

    Netseva-Porcheva Tatyana

    2010-01-01

    The main aim of the paper is to present the value-based pricing. Therefore, the comparison between two approaches of pricing is made - cost-based pricing and value-based pricing. The 'Price sensitively meter' is presented. The other topic of the paper is the perceived value - meaning of the perceived value, the components of perceived value, the determination of perceived value and the increasing of perceived value. In addition, the best company strategies in matrix 'value-cost' are outlined. .

  4. Network-Based Effectiveness

    Friman, Henrik

    2006-01-01

    ...) to increase competitive advantage, innovation, and mission effectiveness. Network-based effectiveness occurs due to the influence of various factors such as people, procedures, technology, and organizations...

  5. Case-based reasoning

    Kolodner, Janet

    1993-01-01

    Case-based reasoning is one of the fastest growing areas in the field of knowledge-based systems and this book, authored by a leader in the field, is the first comprehensive text on the subject. Case-based reasoning systems are systems that store information about situations in their memory. As new problems arise, similar situations are searched out to help solve these problems. Problems are understood and inferences are made by finding the closest cases in memory, comparing and contrasting the problem with those cases, making inferences based on those comparisons, and asking questions whe

  6. Strengths-based Learning

    Ledertoug, Mette Marie

    -being. The Ph.D.-project in Strength-based learning took place in a Danish school with 750 pupils age 6-16 and a similar school was functioning as a control group. The presentation will focus on both the aware-explore-apply processes and the practical implications for the schools involved, and on measurable......Strength-based learning - Children͛s Character Strengths as Means to their Learning Potential͛ is a Ph.D.-project aiming to create a strength-based mindset in school settings and at the same time introducing strength-based interventions as specific tools to improve both learning and well...

  7. Monitoring Knowledge Base (MKB)

    U.S. Environmental Protection Agency — The Monitoring Knowledge Base (MKB) is a compilation of emissions measurement and monitoring techniques associated with air pollution control devices, industrial...

  8. Imagery Data Base Facility

    Federal Laboratory Consortium — The Imagery Data Base Facility supports AFRL and other government organizations by providing imagery interpretation and analysis to users for data selection, imagery...

  9. Game-Based Teaching

    Hanghøj, Thorkild

    2013-01-01

    This chapter outlines theoretical and empirical perspectives on how Game-Based Teaching can be integrated within the context of formal schooling. Initially, this is done by describing game scenarios as models for possible actions that need to be translated into curricular knowledge practices...... approaches to game-based teaching, which may or may not correspond with the pedagogical models of particular games....

  10. Secure base stations

    Bosch, Peter; Brusilovsky, Alec; McLellan, Rae; Mullender, Sape J.; Polakos, Paul

    2009-01-01

    With the introduction of the third generation (3G) Universal Mobile Telecommunications System (UMTS) base station router (BSR) and fourth generation (4G) base stations, such as the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Evolved Node B (eNB), it has become important to

  11. Hydrogel based occlusion systems

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A.; Mendes, E.; Neves, H.P.; Herijgers, P.; Verbrugghe, Y.; Shacham, Y.; Engel, L.; Krylov, V.

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a

  12. Diffusion Based Photon Mapping

    Schjøth, Lars; Fogh Olsen, Ole; Sporring, Jon

    2007-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  13. Diffusion Based Photon Mapping

    Schjøth, Lars; Olsen, Ole Fogh; Sporring, Jon

    2006-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  14. Zero-Based Budgeting.

    Wichowski, Chester

    1979-01-01

    The zero-based budgeting approach is designed to achieve the greatest benefit with the fewest undesirable consequences. Seven basic steps make up the zero-based decision-making process: (1) identifying program goals, (2) classifying goals, (3) identifying resources, (4) reviewing consequences, (5) developing decision packages, (6) implementing a…

  15. Office-based anaesthesia

    infection, and consistency in nursing personnel. In the USA 17 -. 24% of all elective ambulatory surgery is ... knowledge base or personality to deal with the OBA environment. Compared with hospitals, office-based facilities currently ... disease or major cardiovascular risk factors). Intravenous access via a flexible cannula is.

  16. Knowledge base mechanisms

    Suwa, M; Furukawa, K; Makinouchi, A; Mizoguchi, T; Mizoguchi, F; Yamasaki, H

    1982-01-01

    One of the principal goals of the Fifth Generation Computer System Project for the coming decade is to develop a methodology for building knowledge information processing systems which will provide people with intelligent agents. The key notion of the fifth generation computer system is knowledge used for problem solving. In this paper the authors describe the plan of Randd on knowledge base mechanisms. A knowledge representation system is to be designed to support knowledge acquisition for the knowledge information processing systems. The system will include a knowledge representation language, a knowledge base editor and a debugger. It is also expected to perform as a kind of meta-inference system. In order to develop the large scale knowledge base systems, a knowledge base mechanism based on the relational model is to be studied in the earlier stage of the project. Distributed problem solving is also one of the main issues of the project. 19 references.

  17. Skull base tumours

    Borges, Alexandra [Instituto Portugues de Oncologia Francisco Gentil, Servico de Radiologia, Rua Professor Lima Basto, 1093 Lisboa Codex (Portugal)], E-mail: borgesalexandra@clix.pt

    2008-06-15

    With the advances of cross-sectional imaging radiologists gained an increasing responsibility in the management of patients with skull base pathology. As this anatomic area is hidden to clinical exam, surgeons and radiation oncologists have to rely on imaging studies to plan the most adequate treatment. To fulfil these endeavour radiologists need to be knowledgeable about skull base anatomy, about the main treatment options available, their indications and contra-indications and needs to be aware of the wide gamut of pathologies seen in this anatomic region. This article will provide a radiologists' friendly approach to the central skull base and will review the most common central skull base tumours and tumours intrinsic to the bony skull base.

  18. Evidence-based radiography

    Hafslund, Bjorg; Clare, Judith; Graverholt, Birgitte; Wammen Nortvedt, Monica

    2008-01-01

    Evidence-based practice (EBP) offers the integration of the best research evidence with clinical knowledge and expertise and patient values. EBP is a well known term in health care. This paper discusses the implementation of EBP into radiography and introduces the term evidence-based radiography. Evidence-based radiography is radiography informed and based on the combination of clinical expertise and the best available research-based evidence, patient preferences and resources available. In Norway, EBP in radiography is being debated and radiographers are discussing the challenges of implementing EBP in both academic and clinical practice. This discussion paper explains why EBP needs to be a basis for a radiography curriculum and a part of radiographers' practice. We argue that Norwegian radiographers must increase participation in research and developing practice within their specific radiographic domain

  19. Skull base tumours

    Borges, Alexandra

    2008-01-01

    With the advances of cross-sectional imaging radiologists gained an increasing responsibility in the management of patients with skull base pathology. As this anatomic area is hidden to clinical exam, surgeons and radiation oncologists have to rely on imaging studies to plan the most adequate treatment. To fulfil these endeavour radiologists need to be knowledgeable about skull base anatomy, about the main treatment options available, their indications and contra-indications and needs to be aware of the wide gamut of pathologies seen in this anatomic region. This article will provide a radiologists' friendly approach to the central skull base and will review the most common central skull base tumours and tumours intrinsic to the bony skull base

  20. Design-Based Research

    Gynther, Karsten; Christensen, Ove; Petersen, Trine Brun

    2012-01-01

    I denne artikel introduceres Design Based Research for første gang på dansk i et videnskabeligt tidsskrift. Artiklen præsenterer de grundlæggende antagelser, som ligger til grund for Design Based Research-traditionen, og artiklen diskuterer de principper, som ligger til grund for gennemførelse af...... et DBR-forskningsprojekt. Med udgangspunkt i forsknings- og udviklingsprojektet ELYK: E-læring, Yderområder og Klyngedannelse, præsenteres den innovationsmodel, som projektet har udviklet med udgangspunkt i Design Based Research traditionen. ELYKs DBR innovationsmodel har vist sig effektiv i forhold...

  1. Nature-based integration

    Pitkänen, Kati; Oratuomi, Joose; Hellgren, Daniela

    Increased attention to, and careful planning of the integration of migrants into Nordic societies is ever more important. Nature based integration is a new solution to respond to this need. This report presents the results of a Nordic survey and workshop and illustrates current practices of nature...... based integration by case study descriptions from Denmark, Sweden Norway and Finland. Across Nordic countries several practical projects and initiatives have been launched to promote the benefits of nature in integration and there is also growing academic interest in the topic. Nordic countries have...... the potential of becoming real forerunners in nature based integration even at the global scale....

  2. Data base management study

    1976-01-01

    Data base management techniques and applicable equipment are described. Recommendations which will assist potential NASA data users in selecting and using appropriate data base management tools and techniques are presented. Classes of currently available data processing equipment ranging from basic terminals to large minicomputer systems were surveyed as they apply to the needs of potential SEASAT data users. Cost and capabilities projections for this equipment through 1985 were presented. A test of a typical data base management system was described, as well as the results of this test and recommendations to assist potential users in determining when such a system is appropriate for their needs. The representative system tested was UNIVAC's DMS 1100.

  3. Value-based pricing

    Netseva-Porcheva Tatyana

    2010-01-01

    Full Text Available The main aim of the paper is to present the value-based pricing. Therefore, the comparison between two approaches of pricing is made - cost-based pricing and value-based pricing. The 'Price sensitively meter' is presented. The other topic of the paper is the perceived value - meaning of the perceived value, the components of perceived value, the determination of perceived value and the increasing of perceived value. In addition, the best company strategies in matrix 'value-cost' are outlined. .

  4. QuickBase

    Conner, Nancy

    2007-01-01

    Ready to put Intuit's QuickBase to work? Our new Missing Manual shows you how to capture, modify, share, and manage data and documents with this web-based data-sharing program quickly and easily. No longer do you have to coordinate your team through a blizzard of emails or play frustrating games of "guess which document is the right one."QuickBase saves your organization time and money, letting you manage and share the information that makes your business tick: sales figures, project timelines, drafts of documents, purchase or work requests--whatever information you need to keep business flowi

  5. The Effect of Growth Temperature and V/III Flux Ratio of MOCVD Antimony Based Semiconductors on Growth Rate and Surface Morphology

    Ramelan Ari Handono

    2017-01-01

    Full Text Available Epitaxial Alx Ga1-x Sb layers on GaSb and GaAs substrates have been grown by atmospheric pressure metalorganic chemical vapor deposition using TMAl, TMGa and TMSb. Nomarski microscope and a profiler were employed to examine the surface morphology and growth rate of the samples. We report the effect of growth temperature and V/III flux ratio on growth rate and surface morphology. Growth temperatures in the range of 520°C and 680°C and V/III ratios from 1 to 5 have been investigated. A growth rate activation energy of 0.73 eV was found. At low growth temperatures between 520 and 540°C, the surface morphology is poor due to antimonide precipitates associated with incomplete decomposition of the TMSb. For layers grown on GaAs at 580°C and 600°C with a V/III ratio of 3 a high quality surface morphology is typical, with a mirror-like surface and good composition control. It was found that a suitable growth temperature and V/III flux ratio was beneficial for producing good AlGaSb layers. Undoped AlGaSb grown at 580°C with a V/III flux ratio of 3 at the rate of 3.5 μm/hour shows p-type conductivity with smooth surface morphology

  6. Cheboygan Vessel Base

    Federal Laboratory Consortium — Cheboygan Vessel Base (CVB), located in Cheboygan, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). CVB was established by congressional...

  7. Hanscom Air Force Base

    Federal Laboratory Consortium — MIT Lincoln Laboratory occupies 75 acres (20 acres of which are MIT property) on the eastern perimeter of Hanscom Air Force Base, which is at the nexus of Lexington,...

  8. Network-Based Effectiveness

    Friman, Henrik

    2006-01-01

    ... (extended from Leavitt, 1965). This text identifies aspects of network-based effectiveness that can benefit from a better understanding of leadership and management development of people, procedures, technology, and organizations...

  9. WormBase

    U.S. Department of Health & Human Services — WormBase is an international consortium of biologists and computer scientists dedicated to providing the research community with accurate, current, accessible...

  10. Kelomehele preemia Baseli festivalil

    2000-01-01

    Baselis festivalil "VIPER - International Festival for Film Video and New Media" tunnistati parimaks CD-ROMiks Gustav Deutschi/Anna Schimeki "Odysee today", netiprojektiks itaallaste "01.ORG", äramärkimispreemia - Raivo Kelomehe "Videoweaver"

  11. Risk based modelling

    Chapman, O.J.V.; Baker, A.E.

    1993-01-01

    Risk based analysis is a tool becoming available to both engineers and managers to aid decision making concerning plant matters such as In-Service Inspection (ISI). In order to develop a risk based method, some form of Structural Reliability Risk Assessment (SRRA) needs to be performed to provide a probability of failure ranking for all sites around the plant. A Probabilistic Risk Assessment (PRA) can then be carried out to combine these possible events with the capability of plant safety systems and procedures, to establish the consequences of failure for the sites. In this way the probability of failures are converted into a risk based ranking which can be used to assist the process of deciding which sites should be included in an ISI programme. This paper reviews the technique and typical results of a risk based ranking assessment carried out for nuclear power plant pipework. (author)

  12. Problem Based Learning

    de Graaff, Erik; Guerra, Aida

    , the key principles remain the same everywhere. Graaff & Kolmos (2003) identify the main PBL principles as follows: 1. Problem orientation 2. Project organization through teams or group work 3. Participant-directed 4. Experiental learning 5. Activity-based learning 6. Interdisciplinary learning and 7...... model and in general problem based and project based learning. We apply the principle of teach as you preach. The poster aims to outline the visitors’ workshop programme showing the results of some recent evaluations.......Problem-Based Learning (PBL) is an innovative method to organize the learning process in such a way that the students actively engage in finding answers by themselves. During the past 40 years PBL has evolved and diversified resulting in a multitude in variations in models and practices. However...

  13. Biomimetics: nature based innovation

    Bar-Cohen, Yoseph

    2012-01-01

    "Based on the concept that nature offers numerous sources of inspiration for inventions related to mechanisms, materials, processes, and algorithms, this book covers the topic of biomimetics and the inspired innovation...

  14. BaseMap

    California Natural Resource Agency — The goal of this project is to provide a convenient base map that can be used as a starting point for CA projects. It's simple, but designed to work at a number of...

  15. PHENANTHROLINE TEMPLATED SCHIFF BASE

    DNA in intercalative mode and in the development of unique chemotherapeutics where they impact on the ... between base pairs of DNA. .... h, i, j, k belong to fragmentation products of impap. ..... Sm(III) complex and herring sperm DNA. Bull.

  16. Lunar resource base

    Pulley, John; Wise, Todd K.; Roy, Claude; Richter, Phil

    A lunar base that exploits local resources to enhance the productivity of a total SEI scenario is discussed. The goals were to emphasize lunar science and to land men on Mars in 2016 using significant amounts of lunar resources. It was assumed that propulsion was chemical and the surface power was non-nuclear. Three phases of the base build-up are outlined, the robotic emplacement of the first elements is detailed and a discussion of future options is included.

  17. Participatory design based research

    Dau, Susanne; Bach Jensen, Louise; Falk, Lars

    This poster reveal how participatory design based research by the use of a CoED inspired creative process can be used for designing solutions to problems regarding students study activities outside campus.......This poster reveal how participatory design based research by the use of a CoED inspired creative process can be used for designing solutions to problems regarding students study activities outside campus....

  18. Maintaining Relationship Based Procurement

    Davis, Peter

    2012-01-01

    Alliance and relationship projects are increasingin number and represent a large pool of work. Tobe successful relationship style contracts dependon soft-dollar factors, particularly the participants'ability to work together within an agreedframework, generally they are not based on lowbid tendering. Participants should be prepared todo business in an open environment based ontrust and mutually agreed governance. Theresearch evaluates relationship maintenance inthe implementation phase of con...

  19. Game-based telerehabilitation.

    Lange, B; Flynn, Sheryl M; Rizzo, A A

    2009-03-01

    This article summarizes the recent accomplishments and current challenges facing game-based virtual reality (VR) telerehabilitation. Specifically this article addresses accomplishments relative to realistic practice scenarios, part to whole practice, objective measurement of performance and progress, motivation, low cost, interaction devices and game design. Furthermore, a description of the current challenges facing game based telerehabilitation including the packaging, internet capabilities and access, data management, technical support, privacy protection, seizures, distance trials, scientific scrutiny and support from insurance companies.

  20. REST based mobile applications

    Rambow, Mark; Preuss, Thomas; Berdux, Jörg; Conrad, Marc

    2008-02-01

    Simplicity is the major advantage of REST based webservices. Whereas SOAP is widespread in complex, security sensitive business-to-business aplications, REST is widely used for mashups and end-user centric applicatons. In that context we give an overview of REST and compare it to SOAP. Furthermore we apply the GeoDrawing application as an example for REST based mobile applications and emphasize on pros and cons for the use of REST in mobile application scenarios.

  1. Swarm-based medicine.

    Putora, Paul Martin; Oldenburg, Jan

    2013-09-19

    Occasionally, medical decisions have to be taken in the absence of evidence-based guidelines. Other sources can be drawn upon to fill in the gaps, including experience and intuition. Authorities or experts, with their knowledge and experience, may provide further input--known as "eminence-based medicine". Due to the Internet and digital media, interactions among physicians now take place at a higher rate than ever before. With the rising number of interconnected individuals and their communication capabilities, the medical community is obtaining the properties of a swarm. The way individual physicians act depends on other physicians; medical societies act based on their members. Swarm behavior might facilitate the generation and distribution of knowledge as an unconscious process. As such, "swarm-based medicine" may add a further source of information to the classical approaches of evidence- and eminence-based medicine. How to integrate swarm-based medicine into practice is left to the individual physician, but even this decision will be influenced by the swarm.

  2. Evidence-Based Toxicology.

    Hoffmann, Sebastian; Hartung, Thomas; Stephens, Martin

    Evidence-based toxicology (EBT) was introduced independently by two groups in 2005, in the context of toxicological risk assessment and causation as well as based on parallels between the evaluation of test methods in toxicology and evidence-based assessment of diagnostics tests in medicine. The role model of evidence-based medicine (EBM) motivated both proposals and guided the evolution of EBT, whereas especially systematic reviews and evidence quality assessment attract considerable attention in toxicology.Regarding test assessment, in the search of solutions for various problems related to validation, such as the imperfectness of the reference standard or the challenge to comprehensively evaluate tests, the field of Diagnostic Test Assessment (DTA) was identified as a potential resource. DTA being an EBM discipline, test method assessment/validation therefore became one of the main drivers spurring the development of EBT.In the context of pathway-based toxicology, EBT approaches, given their objectivity, transparency and consistency, have been proposed to be used for carrying out a (retrospective) mechanistic validation.In summary, implementation of more evidence-based approaches may provide the tools necessary to adapt the assessment/validation of toxicological test methods and testing strategies to face the challenges of toxicology in the twenty first century.

  3. LDEF materials data bases

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base.

  4. Paper based electronics platform

    Nassar, Joanna Mohammad

    2017-07-20

    A flexible and non-functionalized low cost paper-based electronic system platform fabricated from common paper, such as paper based sensors, and methods of producing paper based sensors, and methods of sensing using the paper based sensors are provided. A method of producing a paper based sensor can include the steps of: a) providing a conventional paper product to serve as a substrate for the sensor or as an active material for the sensor or both, the paper product not further treated or functionalized; and b) applying a sensing element to the paper substrate, the sensing element selected from the group consisting of a conductive material, the conductive material providing contacts and interconnects, sensitive material film that exhibits sensitivity to pH levels, a compressible and/or porous material disposed between a pair of opposed conductive elements, or a combination of two of more said sensing elements. The method of sensing can further include measuring, using the sensing element, a change in resistance, a change in voltage, a change in current, a change in capacitance, or a combination of any two or more thereof.

  5. Gossip-Based Dissemination

    Friedman, Roy; Kermarrec, Anne-Marie; Miranda, Hugo; Rodrigues, Luís

    Gossip-based networking has emerged as a viable approach to disseminate information reliably and efficiently in large-scale systems. Initially introduced for database replication [222], the applicability of the approach extends much further now. For example, it has been applied for data aggregation [415], peer sampling [416] and publish/subscribe systems [845]. Gossip-based protocols rely on a periodic peer-wise exchange of information in wired systems. By changing the way each peer is selected for the gossip communication, and which data are exchanged and processed [451], gossip systems can be used to perform different distributed tasks, such as, among others: overlay maintenance, distributed computation, and information dissemination (a collection of papers on gossip can be found in [451]). In a wired setting, the peer sampling service, allowing for a random or specific peer selection, is often provided as an independent service, able to operate independently from other gossip-based services [416].

  6. Iron-based superconductivity

    Johnson, Peter D; Yin, Wei-Guo

    2015-01-01

    This volume presents an in-depth review of experimental and theoretical studies on the newly discovered Fe-based superconductors.  Following the Introduction, which places iron-based superconductors in the context of other unconventional superconductors, the book is divided into three sections covering sample growth, experimental characterization, and theoretical understanding.  To understand the complex structure-property relationships of these materials, results from a wide range of experimental techniques and theoretical approaches are described that probe the electronic and magnetic proper

  7. Evidence-Based Development

    Hertzum, Morten; Simonsen, Jesper

    2004-01-01

    Systems development is replete with projects that represent substantial resource investments but result in systems that fail to meet users’ needs. Evidence-based development is an emerging idea intended to provide means for managing customer-vendor relationships and working systematically toward...... meeting customer needs. We are suggesting that the effects of the use of a system should play a prominent role in the contractual definition of IT projects and that contract fulfilment should be determined on the basis of evidence of these effects. Based on two ongoing studies of home-care management...

  8. Video-based rendering

    Magnor, Marcus A

    2005-01-01

    Driven by consumer-market applications that enjoy steadily increasing economic importance, graphics hardware and rendering algorithms are a central focus of computer graphics research. Video-based rendering is an approach that aims to overcome the current bottleneck in the time-consuming modeling process and has applications in areas such as computer games, special effects, and interactive TV. This book offers an in-depth introduction to video-based rendering, a rapidly developing new interdisciplinary topic employing techniques from computer graphics, computer vision, and telecommunication en

  9. Process-based costing.

    Lee, Robert H; Bott, Marjorie J; Forbes, Sarah; Redford, Linda; Swagerty, Daniel L; Taunton, Roma Lee

    2003-01-01

    Understanding how quality improvement affects costs is important. Unfortunately, low-cost, reliable ways of measuring direct costs are scarce. This article builds on the principles of process improvement to develop a costing strategy that meets both criteria. Process-based costing has 4 steps: developing a flowchart, estimating resource use, valuing resources, and calculating direct costs. To illustrate the technique, this article uses it to cost the care planning process in 3 long-term care facilities. We conclude that process-based costing is easy to implement; generates reliable, valid data; and allows nursing managers to assess the costs of new or modified processes.

  10. Inkjet-based micromanufacturing

    Korvink, Jan G; Shin, Dong-Youn; Brand, Oliver; Fedder, Gary K; Hierold, Christofer; Tabata, Osamu

    2012-01-01

    Inkjet-based Micromanufacturing Inkjet technology goes way beyond putting ink on paper: it enables simpler, faster and more reliable manufacturing processes in the fields of micro- and nanotechnology. Modern inkjet heads are per se precision instruments that deposit droplets of fluids on a variety of surfaces in programmable, repeating patterns, allowing, after suitable modifications and adaptations, the manufacturing of devices such as thin-film transistors, polymer-based displays and photovoltaic elements. Moreover, inkjet technology facilitates the large-scale production of flexible RFID tr

  11. On multivariate Wilson bases

    Bownik, Marcin; Jakobsen, Mads Sielemann; Lemvig, Jakob

    2017-01-01

    A Wilson system is a collection of finite linear combinations of time frequency shifts of a square integrable function. In this paper we give an account of the construction of bimodular Wilson bases in higher dimensions from Gabor frames of redundancy two.......A Wilson system is a collection of finite linear combinations of time frequency shifts of a square integrable function. In this paper we give an account of the construction of bimodular Wilson bases in higher dimensions from Gabor frames of redundancy two....

  12. Electron and hole photoemission detection for band offset determination of tunnel field-effect transistor heterojunctions

    Li, Wei; Zhang, Qin; Kirillov, Oleg A.; Levin, Igor; Richter, Curt A.; Gundlach, David J.; Nguyen, N. V.; Bijesh, R.; Datta, S.; Liang, Yiran; Peng, Lian-Mao; Liang, Xuelei

    2014-01-01

    We report experimental methods to ascertain a complete energy band alignment of a broken-gap tunnel field-effect transistor based on an InAs/GaSb hetero-junction. By using graphene as an optically transparent electrode, both the electron and hole barrier heights at the InAs/GaSb interface can be quantified. For a Al 2 O 3 /InAs/GaSb layer structure, the barrier height from the top of the InAs and GaSb valence bands to the bottom of the Al 2 O 3 conduction band is inferred from electron emission whereas hole emissions reveal the barrier height from the top of the Al 2 O 3 valence band to the bottom of the InAs and GaSb conduction bands. Subsequently, the offset parameter at the broken gap InAs/GaSb interface is extracted and thus can be used to facilitate the development of predicted models of electron quantum tunneling efficiency and transistor performance

  13. Development of nano-fabrication technique utilizing self-organizational behavior of point defects induced by ion irradiation

    Nitta, Noriko [Department of Environmental Systems Engineering, Kochi University of Technology, Tosayamada-Cho, Kochi-Prefecture 782-8502 (Japan); Taniwaki, Masafumi [Department of Environmental Systems Engineering, Kochi University of Technology, Tosayamada-Cho, Kochi-Prefecture 782-8502 (Japan)]. E-mail: taniwaki.masafumi@kochi-tech.ac.jp

    2006-04-01

    The present authors proposed a novel nano-fabrication technique that is able to arrange the fine cells orderly, based on their finding in GaSb implanted at a low temperature. In this article, first the experimental results that anomalous cellular structure was formed in GaSb by ion implantation is introduced and the self-organizational formation mechanism of the structure is described. Next a nano-fabrication technique that utilizes focused ion beam is described. This technique consists of two procedures, i.e. the formation process of the voids array and the development of the initial array to ordered cellular structure. Finally, the nano-fabrication is actually performed by this technique and their results are reported. Fabrication succeeded in structures where the dot (cell) interval was 100 nm or larger. The minimum ion dose for initial voids which develops to the ordered cellular structure is evaluated. It is also shown that the substrate temperature during implantation is an essential parameter for this technique.

  14. Superconducting proximity effect in MBE grown Nb-InAs junctions

    Kan, Carolyn; Xue, Chi; Law, Stephanie; Eckstein, James

    2013-03-01

    Several proposals for the realization of Majorana fermions rely on excellent quality proximity coupling between a superconductor and a high-mobility semiconductor. We examine the long-range proximity coupling between MBE-grown InAs and in situ grown superconducting overlayers by fabricating transport devices, and investigate the effect of substrate choice and growth conditions on the quality of the MBE InAs. GaAs is commonly available as a high quality insulating substrate. Overcoming its lattice mismatch with InAs using GaSb and AlSb layers results in locally smooth terraced surfaces, but global spiral dislocation structures also appear and have a negative impact on the InAs mobility. Growing InAs on homoepitaxial GaSb results in improved morphology and increases the mean free path. We compare the proximity effect in devices made both ways. This material is based upon work supported by the U.S. Department of Energy, Division of Materials Sciences under Award No. DE-FG02 07ER46453, through the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign.

  15. Cellular structure formed by ion-implantation-induced point defect

    Nitta, N.; Taniwaki, M.; Hayashi, Y.; Yoshiie, T.

    2006-01-01

    The authors have found that a cellular defect structure is formed on the surface of Sn + ion implanted GaSb at a low temperature and proposed its formation mechanism based on the movement of the induced point defects. This research was carried out in order to examine the validity of the mechanism by clarifying the effect of the mobility of the point defects on the defect formation. The defect structure on the GaSb surfaces implanted at cryogenic temperature and room temperature was investigated by scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM) observation. In the sample implanted at room temperature, the sponge-like structure (a pileup of voids) was formed and the cellular structure, as observed at a low temperature, did not develop. This behavior was explained by the high mobility of the vacancies during implantation at room temperature, and the proposed idea that the defect formation process is dominated by the induced point defects was confirmed

  16. Development of nano-fabrication technique utilizing self-organizational behavior of point defects induced by ion irradiation

    Nitta, Noriko; Taniwaki, Masafumi

    2006-01-01

    The present authors proposed a novel nano-fabrication technique that is able to arrange the fine cells orderly, based on their finding in GaSb implanted at a low temperature. In this article, first the experimental results that anomalous cellular structure was formed in GaSb by ion implantation is introduced and the self-organizational formation mechanism of the structure is described. Next a nano-fabrication technique that utilizes focused ion beam is described. This technique consists of two procedures, i.e. the formation process of the voids array and the development of the initial array to ordered cellular structure. Finally, the nano-fabrication is actually performed by this technique and their results are reported. Fabrication succeeded in structures where the dot (cell) interval was 100 nm or larger. The minimum ion dose for initial voids which develops to the ordered cellular structure is evaluated. It is also shown that the substrate temperature during implantation is an essential parameter for this technique

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

    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.

  18. Ion beam nanopatterning of III-V semiconductors: consistency of experimental and simulation trends within a chemistry-driven theory.

    El-Atwani, O; Norris, S A; Ludwig, K; Gonderman, S; Allain, J P

    2015-12-16

    Several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.

  19. Supramolecular fluorene based materials

    Abbel, R.J.

    2008-01-01

    This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical

  20. EPICS based DAQ system

    Cheng Weixing; Chen Yongzhong; Zhou Weimin; Ye Kairong; Liu Dekang

    2002-01-01

    EPICS is the most popular developing platform to build control system and beam diagnostic system in modern physics experiment facilities. An EPICS based data acquisition system was built in Redhat 6.2 operation system. The system is successfully used in the beam position monitor mapping, it improves the mapping process a lot

  1. Scenario-based strategizing

    Lehr, Thomas; Lorenz, Ullrich; Willert, Markus

    2017-01-01

    -based efficacy and robustness. To facilitate the colla- borative strategizing in teams, we propose a matrix with robustness and efficacy as the two axes, which we call the Parmenides Matrix. We assess the impact of the novel approach by applying it in two cases, at a govern- mental agency (German Environmental...

  2. Dictionary Based Image Segmentation

    Dahl, Anders Bjorholm; Dahl, Vedrana Andersen

    2015-01-01

    We propose a method for weakly supervised segmentation of natural images, which may contain both textured or non-textured regions. Our texture representation is based on a dictionary of image patches. To divide an image into separated regions with similar texture we use an implicit level sets...

  3. Web Based VRML Modelling

    Kiss, S.; Sarfraz, M.

    2004-01-01

    Presents a method to connect VRML (Virtual Reality Modeling Language) and Java components in a Web page using EAI (External Authoring Interface), which makes it possible to interactively generate and edit VRML meshes. The meshes used are based on regular grids, to provide an interaction and modeling

  4. Surfel Based Geometry Resonstruction

    Andersen, Vedrana; Aanæs, Henrik; Bærentzen, Jakob Andreas

    2010-01-01

    We propose a method for retrieving a piecewise smooth surface from noisy data. In data acquired by a scanning process sampled points are almost never on the discontinuities making reconstruction of surfaces with sharp features difficult. Our method is based on a Markov Random Field (MRF) formulat...

  5. Diffusion Based Photon Mapping

    Schjøth, Lars; Sporring, Jon; Fogh Olsen, Ole

    2008-01-01

    . To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while...

  6. Evidence-based policy

    Vohnsen, Nina Holm

    2013-01-01

    -makers and the research community (e.g. Boden & Epstein 2006; House of Commons 2006; Cartwright et al 2009; Rod 2010; Vohnsen 2011). This article intends to draw out some general pitfalls in the curious meeting of science and politics by focusing on a particular attempt to make evidence-based legislation in Denmark (for...

  7. Project-Based Science

    Krajcik, Joe

    2015-01-01

    Project-based science is an exciting way to teach science that aligns with the "Next Generation Science Standards" ("NGSS"). By focusing on core ideas along with practices and crosscutting concepts, classrooms become learning environments where teachers and students engage in science by designing and carrying out…

  8. Financing Competency Based Programs.

    Daniel, Annette

    Literature on the background, causes, and current prevalence of competency based programs is synthesized in this report. According to one analysis of the actual and probable costs of minimum competency testing, estimated costs for test development, test administration, bureaucratic structures, and remedial programs for students who cannot pass the…

  9. Computer Based Expert Systems.

    Parry, James D.; Ferrara, Joseph M.

    1985-01-01

    Claims knowledge-based expert computer systems can meet needs of rural schools for affordable expert advice and support and will play an important role in the future of rural education. Describes potential applications in prediction, interpretation, diagnosis, remediation, planning, monitoring, and instruction. (NEC)

  10. Community-Based Care

    ... our e-newsletter! Aging & Health A to Z Community-Based Care Basic Facts & Information A variety of healthcare options ... day care centers are either in churches or community centers. Adult day care is commonly used to care for people who ...

  11. Polymer based tunneling sensor

    Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

    2006-01-01

    A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

  12. Evidence-based guidelines

    Rovira, Àlex; Wattjes, Mike P; Tintoré, Mar

    2015-01-01

    diagnosis in patients with MS. The aim of this article is to provide guidelines for the implementation of MRI of the brain and spinal cord in the diagnosis of patients who are suspected of having MS. These guidelines are based on an extensive review of the recent literature, as well as on the personal...

  13. School Based Health Centers

    Children's Aid Society, 2012

    2012-01-01

    School Based Health Centers (SBHC) are considered by experts as one of the most effective and efficient ways to provide preventive health care to children. Few programs are as successful in delivering health care to children at no cost to the patient, and where they are: in school. For many underserved children, The Children's Aid Society's…

  14. Internet based benchmarking

    Bogetoft, Peter; Nielsen, Kurt

    2005-01-01

    We discuss the design of interactive, internet based benchmarking using parametric (statistical) as well as nonparametric (DEA) models. The user receives benchmarks and improvement potentials. The user is also given the possibility to search different efficiency frontiers and hereby to explore...

  15. Problem-based learning

    Loyens, Sofie; Kirschner, Paul A.; Paas, Fred

    2010-01-01

    Loyens, S. M. M., Kirschner, P. A., & Paas, F. (2011). Problem-based learning. In S. Graham (Editor-in-Chief), A. Bus, S. Major, & L. Swanson (Associate Editors), APA educational psychology handbook: Vol. 3. Application to learning and teaching (pp. 403-425). Washington, DC: American Psychological

  16. Base tree property

    Balcar, B.; Doucha, Michal; Hrušák, M.

    2015-01-01

    Roč. 32, č. 1 (2015), s. 69-81 ISSN 0167-8094 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : forcing * Boolean algebras * base tree Subject RIV: BA - General Mathematics Impact factor: 0.614, year: 2015 http://link.springer.com/article/10.1007/s11083-013-9316-2

  17. unsymmetrical Schiff base complexes

    the effect of the substitutional groups of the Schiff base on the oxidation and reduction potentials, we used ... Electrochemistry of these complexes showed that the presence of electron .... a solution of the ligand (1 mmol) in methanol (15 mL).

  18. Home-based care

    Mrs. Patience Edoho Samson-Akpan

    study was to ascertain the relationship between home-based care and quality of life of PLWHA in support groups in. Calabar South Local Government Area. A correlational design was utilized and a purposive sample of 74 PLWHA participated in the study. A self developed and well validated questionnaire was used for data ...

  19. Mutually unbiased bases

    Mutually unbiased bases play an important role in quantum cryptography [2] and in the optimal determination of the density operator of an ensemble [3,4]. A density operator ρ in N-dimensions depends on N2 1 real quantities. With the help of MUB's, any such density operator can be encoded, in an optimal way, in terms of ...

  20. Scenario-based strategizing

    Lehr, Thomas; Lorenz, Ullrich; Willert, Markus

    2017-01-01

    For over 40 years, scenarios have been promoted as a key technique for forming strategies in uncertain en- vironments. However, many challenges remain. In this article, we discuss a novel approach designed to increase the applicability of scenario-based strategizing in top management teams. Drawi...... Ministry) and a firm affected by disruptive change (Bosch, leading global supplier of technology and solutions)....

  1. 80537 based distance relay

    Pedersen, Knud Ole Helgesen

    1999-01-01

    A method for implementing a digital distance relay in the power system is described.Instructions are given on how to program this relay on a 80537 based microcomputer system.The problem is used as a practical case study in the course 53113: Micocomputer applications in the power system.The relay...

  2. Mojave Base Station Implementation

    Koscielski, C. G.

    1984-01-01

    A 12.2 meter diameter X-Y mount antenna was reconditioned for use by the crustal dynamic project as a fixed base station. System capabilities and characteristics and key performance parameters for subsystems are presented. The implementation is completed.

  3. Model-based consensus

    Boumans, M.; Martini, C.; Boumans, M.

    2014-01-01

    The aim of the rational-consensus method is to produce "rational consensus", that is, "mathematical aggregation", by weighing the performance of each expert on the basis of his or her knowledge and ability to judge relevant uncertainties. The measurement of the performance of the experts is based on

  4. Model-based consensus

    Boumans, Marcel

    2014-01-01

    The aim of the rational-consensus method is to produce “rational consensus”, that is, “mathematical aggregation”, by weighing the performance of each expert on the basis of his or her knowledge and ability to judge relevant uncertainties. The measurement of the performance of the experts is based on

  5. Animation-based Sketching

    Vistisen, Peter

    This thesis is based on the results of a three-year long PhD-study at the Department of Communication and Psychology at Aalborg University. The thesis consist of five original papers, a book manuscript, as well as a linking text with the thesis’ research questions, research design, and summary...

  6. Refractive index based measurements

    2014-01-01

    In a method for performing a refractive index based measurement of a property of a fluid such as chemical composition or temperature, a chirp in the local spatial frequency of interference fringes of an interference pattern is reduced by mathematical manipulation of the recorded light intensity...

  7. Performance based fault diagnosis

    Niemann, Hans Henrik

    2002-01-01

    Different aspects of fault detection and fault isolation in closed-loop systems are considered. It is shown that using the standard setup known from feedback control, it is possible to formulate fault diagnosis problems based on a performance index in this general standard setup. It is also shown...

  8. Schiff base ligand

    Unknown

    Low-temperature stoichiometric Schiff base reaction in air in 3 : 1 mole ratio between benz- aldehyde and triethylenetetramine (trien) in methanol yields a novel tetraaza µ-bis(bidentate) acyclic ligand L. It was .... electrochemical work was performed as reported in ..... change in ligand shape through change in oxidation.

  9. ISFET based enzyme sensors

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    This paper reviews the results that have been reported on ISFET based enzyme sensors. The most important improvement that results from the application of ISFETs instead of glass membrane electrodes is in the method of fabrication. Problems with regard to the pH dependence of the response and the

  10. Microcontroller base process emulator

    Jovrea Titus Claudiu

    2009-01-01

    This paper describes the design of a microcontroller base emulator for a conventional industrial process. The emulator is made with microcontroller and is used for testing and evaluating the performances of the industrial regulators. The parameters of the emulated process are fully customizable online and downloadable thru a serial communication from a personal computer.

  11. REST based service composition

    Grönvall, Erik; Ingstrup, Mads; Pløger, Morten

    2011-01-01

    This paper presents an ongoing work developing and testing a Service Composition framework based upon the REST architecture named SECREST. A minimalistic approach have been favored instead of a creating a complete infrastructure. One focus has been on the system's interaction model. Indeed, an aim...

  12. Convolution based profile fitting

    Kern, A.; Coelho, A.A.; Cheary, R.W.

    2002-01-01

    Full text: In convolution based profile fitting, profiles are generated by convoluting functions together to form the observed profile shape. For a convolution of 'n' functions this process can be written as, Y(2θ)=F 1 (2θ)x F 2 (2θ)x... x F i (2θ)x....xF n (2θ). In powder diffractometry the functions F i (2θ) can be interpreted as the aberration functions of the diffractometer, but in general any combination of appropriate functions for F i (2θ) may be used in this context. Most direct convolution fitting methods are restricted to combinations of F i (2θ) that can be convoluted analytically (e.g. GSAS) such as Lorentzians, Gaussians, the hat (impulse) function and the exponential function. However, software such as TOPAS is now available that can accurately convolute and refine a wide variety of profile shapes numerically, including user defined profiles, without the need to convolute analytically. Some of the most important advantages of modern convolution based profile fitting are: 1) virtually any peak shape and angle dependence can normally be described using minimal profile parameters in laboratory and synchrotron X-ray data as well as in CW and TOF neutron data. This is possible because numerical convolution and numerical differentiation is used within the refinement procedure so that a wide range of functions can easily be incorporated into the convolution equation; 2) it can use physically based diffractometer models by convoluting the instrument aberration functions. This can be done for most laboratory based X-ray powder diffractometer configurations including conventional divergent beam instruments, parallel beam instruments, and diffractometers used for asymmetric diffraction. It can also accommodate various optical elements (e.g. multilayers and monochromators) and detector systems (e.g. point and position sensitive detectors) and has already been applied to neutron powder diffraction systems (e.g. ANSTO) as well as synchrotron based

  13. Integrated Case Based and Rule Based Reasoning for Decision Support

    Eshete, Azeb Bekele

    2009-01-01

    This project is a continuation of my specialization project which was focused on studying theoretical concepts related to case based reasoning method, rule based reasoning method and integration of them. The integration of rule-based and case-based reasoning methods has shown a substantial improvement with regards to performance over the individual methods. Verdande Technology As wants to try integrating the rule based reasoning method with an existing case based system. This project focu...

  14. Rock properties data base

    Jackson, R.; Gorski, B.; Gyenge, M.

    1991-03-01

    As mining companies proceed deeper and into areas whose stability is threatened by high and complex stress fields, the science of rock mechanics becomes invaluable in designing underground mine strata control programs. CANMET's Mining Research Laboratories division has compiled a summary of pre- and post-failure mechanical properties of rock types which were tested to provide design data. The 'Rock Properties Data Base' presents the results of these tests, and includes many rock types typical of Canadian mine environments. The data base also contains 'm' and 's' values determined using Hoek and Brown's failure criteria for both pre- and post-failure conditions. 7 refs., 3 tabs., 9 figs., 1 append.

  15. Sparse approximation with bases

    2015-01-01

    This book systematically presents recent fundamental results on greedy approximation with respect to bases. Motivated by numerous applications, the last decade has seen great successes in studying nonlinear sparse approximation. Recent findings have established that greedy-type algorithms are suitable methods of nonlinear approximation in both sparse approximation with respect to bases and sparse approximation with respect to redundant systems. These insights, combined with some previous fundamental results, form the basis for constructing the theory of greedy approximation. Taking into account the theoretical and practical demand for this kind of theory, the book systematically elaborates a theoretical framework for greedy approximation and its applications.  The book addresses the needs of researchers working in numerical mathematics, harmonic analysis, and functional analysis. It quickly takes the reader from classical results to the latest frontier, but is written at the level of a graduate course and do...

  16. Problem Based Game Design

    Reng, Lars; Schoenau-Fog, Henrik

    2011-01-01

    At Aalborg University’s department of Medialogy, we are utilizing the Problem Based Learning method to encourage students to solve game design problems by pushing the boundaries and designing innovative games. This paper is concerned with describing this method, how students employ it in various ...... projects and how they learn to analyse, design, and develop for innovation by using it. We will present various cases to exemplify the approach and focus on how the method engages students and aspires for innovation in digital entertainment and games.......At Aalborg University’s department of Medialogy, we are utilizing the Problem Based Learning method to encourage students to solve game design problems by pushing the boundaries and designing innovative games. This paper is concerned with describing this method, how students employ it in various...

  17. Technology based Education System

    Kant Hiran, Kamal; Doshi, Ruchi; Henten, Anders

    2016-01-01

    Abstract - Education plays a very important role for the development of the country. Education has multiple dimensions from schooling to higher education and research. In all these domains, there is invariably a need for technology based teaching and learning tools are highly demanded in the acad......Abstract - Education plays a very important role for the development of the country. Education has multiple dimensions from schooling to higher education and research. In all these domains, there is invariably a need for technology based teaching and learning tools are highly demanded...... in the academic institutions. Thus, there is a need of comprehensive technology support system to cater the demands of all educational actors. Cloud Computing is one such comprehensive and user-friendly technology support environment that is the need of an hour. Cloud computing is the emerging technology that has...

  18. Knowledge based maintenance

    Sturm, A [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

    1998-12-31

    The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

  19. Knowledge based maintenance

    Sturm, A. [Hamburgische Electacitaets-Werke AG Hamburg (Germany)

    1997-12-31

    The establishment of maintenance strategies is of crucial significance for the reliability of a plant and the economic efficiency of maintenance measures. Knowledge about the condition of components and plants from the technical and business management point of view therefore becomes one of the fundamental questions and the key to efficient management and maintenance. A new way to determine the maintenance strategy can be called: Knowledge Based Maintenance. A simple method for determining strategies while taking the technical condition of the components of the production process into account to the greatest possible degree which can be shown. A software with an algorithm for Knowledge Based Maintenance leads the user during complex work to the determination of maintenance strategies for this complex plant components. (orig.)

  20. Conducting Polymer Based Nanobiosensors

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  1. Fusion safety data base

    Laats, E.T.; Hardy, H.A.

    1983-01-01

    The purpose of this Fusion Safety Data Base Program is to provide a repository of data for the design and development of safe commercial fusion reactors. The program is sponsored by the United States Department of Energy (DOE), Office of Fusion Energy. The function of the program is to collect, examine, permanently store, and make available the safety data to the entire US magnetic-fusion energy community. The sources of data will include domestic and foreign fusion reactor safety-related research programs. Any participant in the DOE Program may use the Data Base Program from his terminal through user friendly dialog and can view the contents in the form of text, tables, graphs, or system diagrams

  2. Maintaining Relationship Based Procurement

    Peter Davis

    2012-11-01

    Full Text Available Alliance and relationship projects are increasingin number and represent a large pool of work. Tobe successful relationship style contracts dependon soft-dollar factors, particularly the participants'ability to work together within an agreedframework, generally they are not based on lowbid tendering. Participants should be prepared todo business in an open environment based ontrust and mutually agreed governance. Theresearch evaluates relationship maintenance inthe implementation phase of constructionalliances - a particular derivative of relationshipstyle contracts. To determine the factors thatcontribute to relationship maintenance forty-nineexperienced Australian alliance projectmanagers were interviewed. The main findingswere; the development of relationships early inthe project form building blocks of success fromwhich relationships are maintained and projectvalue added; quality facilitation plays animportant part in relationship maintenance and ahybrid organisation created as a result of alliancedevelopment overcomes destructiveorganisational boundaries. Relationshipmaintenance is integral to alliance project controland failure to formalise it and pay attention toprocess and past outcomes will undermine analliance project's potential for success.

  3. Location-based Scheduling

    Andersson, Niclas; Christensen, Knud

    on the market. However, CPM is primarily an activity based method that takes the activity as the unit of focus and there is criticism raised, specifically in the case of construction projects, on the method for deficient management of construction work and continuous flow of resources. To seek solutions...... to the identified limitations of the CPM method, an alternative planning and scheduling methodology that includes locations is tested. Location-based Scheduling (LBS) implies a shift in focus, from primarily the activities to the flow of work through the various locations of the project, i.e. the building. LBS uses...... the graphical presentation technique of Line-of-balance, which is adapted for planning and management of work-flows that facilitates resources to perform their work without interruptions caused by other resources working with other activities in the same location. As such, LBS and Lean Construction share...

  4. Trajectory Based Traffic Analysis

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2013-01-01

    We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a......We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point......-and-click analysis, due to a novel and efficient indexing structure. With the web-site daisy.aau.dk/its/spqdemo/we will demonstrate several analyses, using a very large real-world data set consisting of 1.9 billion GPS records (1.5 million trajectories) recorded from more than 13000 vehicles, and touching most...

  5. Carbon Nanotube based Nanotechnolgy

    Meyyappan, M.

    2000-10-01

    Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

  6. Spintronics-based computing

    Prenat, Guillaume

    2015-01-01

    This book provides a comprehensive introduction to spintronics-based computing for the next generation of ultra-low power/highly reliable logic, which is widely considered a promising candidate to replace conventional, pure CMOS-based logic. It will cover aspects from device to system-level, including magnetic memory cells, device modeling, hybrid circuit structure, design methodology, CAD tools, and technological integration methods. This book is accessible to a variety of readers and little or no background in magnetism and spin electronics are required to understand its content.  The multidisciplinary team of expert authors from circuits, devices, computer architecture, CAD and system design reveal to readers the potential of spintronics nanodevices to reduce power consumption, improve reliability and enable new functionality.  .

  7. Knowledge Based Economy Assessment

    Madalina Cristina Tocan

    2012-01-01

    The importance of knowledge-based economy (KBE) in the XXI century is evident. In the article the reflection of knowledge on economy is analyzed. The main point is targeted to the analysis of characteristics of knowledge expression in economy and to the construction of structure of KBE expression. This allows understanding the mechanism of functioning of knowledge economy. The authors highlight the possibility to assess the penetration level of KBE which could manifest itself trough the exist...

  8. Luxury-based Growth

    Shiro Kuwahara

    2006-01-01

    Assuming that there exists a preference for luxury goods and a knowledge spillover from luxury goods production to goods production, this paper constructs an endogenous economic growth model. The model predicts two steady states: one is a steady positive growth state with regard to luxury goods production, and the other is a zero growth state in the absence of luxury goods production. Thus, this study examines the polarization of economies based on luxury goods consumption

  9. Base Stability of Aminocyclopropeniums

    2017-11-01

    PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Research Laboratory Weapons and Materials Research Directorate (ATTN: RDRL-WMM-G) 2800 Powder...Mill Road Adelphi, MD 20783-1138 8. PERFORMING ORGANIZATION REPORT NUMBER ARL-TR-8204 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES...fuel cells to test their utility in anion exchange membranes. While the aminocyclopropeniums showed poor base stability, the cyclopropenium cation

  10. Granular loess classification based

    Browzin, B.S.

    1985-01-01

    This paper discusses how loess might be identified by two index properties: the granulometric composition and the dry unit weight. These two indices are necessary but not always sufficient for identification of loess. On the basis of analyses of samples from three continents, it was concluded that the 0.01-0.5-mm fraction deserves the name loessial fraction. Based on the loessial fraction concept, a granulometric classification of loess is proposed. A triangular chart is used to classify loess

  11. Educational Process Material Base

    Olga Ozerova; Irina Zabaturina; Vera Kuznetsova; Galina Kovaleva

    2012-01-01

    Based on the data obtained by the Institute for Statistical Studies and the Economics of Knowledge, National Research University - Higher School of Economics Olga Ozerova - Head of the Department for Statistics of Education, Institute for Statistical Studies and the Economics of Knowledge, National Research University - Higher School of Economics, Moscow, Russian Federation. Email: Address: 18 Myasnitskaya St., Moscow, 101000, Russian Federation.Irina Zabaturina - senior resea...

  12. Supramolecular fluorene based materials

    Abbel, R.J.

    2008-01-01

    This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical properties. Therefore, a detailed understanding of such organisation processes is essential for the optimisation of the performance of these materials as applied in optoelectronic devices. In order to...

  13. Graphene-based Nanoelectronics

    2013-02-01

    Electrodes were fabricated by drop casting solutions containing the graphene oxide (GO)/CNT/MnAc materials onto titanium (Ti) or stainless steel current...silicon carbide (SiC) substrate can induce a splitting of up to 0.3 eV between the maximum of the valence and minimum of the conduction bands at the...simultaneously hinders the formation of multilayer graphene domains. These results are based on a diffusion-segregation model for carbon precipitation on a Ni

  14. Spiritual-based Leadership

    Pruzan, Peter

    2015-01-01

    Although far from mainstream, the concept of spiritual-based leadership is emerging as an inclusive and yet highly personal approach to leadership that integrates a leader’s inner perspectives on identity, purpose, responsibility and success with her or his decisions and actions in the outer world...... of business—and therefore it is also emerging as a significant framework for understanding, practicing, communicating and teaching the art and profession of leadership....

  15. Arduino based laser control

    Bernal Muñoz, Ferran

    2015-01-01

    ARDUINO is a vey usefull platform for prototypes. In this project ARDUINO will be used for controling a Semiconductor Tuneable Laser. [ANGLÈS] Diode laser for communications control based on an Arduino board. Temperature control implementation. Software and hardware protection for the laser implementation. [CASTELLÀ] Control de un láser de comunicaciones ópticas desde el ordenador utilizando una placa Arduino. Implementación de un control de temperatura y protección software y hardware ...

  16. Design bases - Concrete structures

    Diaz-Llanos Ros, M.

    1993-01-01

    The most suitable title for Section 2 is 'Design Bases', which covers not only calculation but also the following areas: - Structural design concepts. - Project criteria. - Material specifications. These concepts are developed in more detail in the following sections. The numbering in this document is neither complete nor hierarchical since, for easier cross referencing, it corresponds to the paragraphs of Eurocode 2 Part 1 (hereinafter 'EUR-2') which are commented on. (author)

  17. Biosphere data base revision

    Bergstroem, U.; Andersson, K.; Sundblad, B.

    1985-12-01

    The turnover of long-lived radionuclides in the biosphere has been modelled some time ago and the exposure to man was calculated. The nuclides were long-lived actinides and fission products leaking from a simulated deep rock repository for spent nuclear fuel. The data base for these calculations has been updated in the present work and in addition a number of nuclides that were not included in the earlier work have been treated. (G.B.)

  18. Air Force Smart Bases

    2017-10-19

    initiates notification to all personnel on the base, the giant voice announces a lock down, everyone’s smart device shows an alarm requesting...location of the detected sound, they easily find a hunter and send his picture back to the IOC, where the hunter’s identity is verified through facial...computer goes into sleep mode, the thermostat goes back to unoccupied mode and his door locks as he walks through. Meanwhile over in the IOC

  19. Polypeptide based hydrogels

    Hanay, Saltuk

    2018-01-01

    There is a need for biocompatible, biodegradable, 3-D printable and stable hydrogels especially in the areas of tissue engineering, drug delivery, bio-sensing technologies and antimicrobial coatings. The main aim of this Ph.D. work was to fabricate polypeptide based hydrogel which may find a potential application in those fields. Focusing on tyrosine or tryptophan-containing copolypeptides prepared by NCarboxyanhydride (NCA) polymerizations, three different crosslinking strategies have been t...

  20. Knowledge-based utility

    Chwalowski, M.

    1997-01-01

    This presentation provides industry examples of successful marketing practices by companies facing deregulation and competition. The common thread through the examples is that long term survival of today's utility structure is dependent on the strategic role of knowledge. As opposed to regulated monopolies which usually own huge physical assets and have very little intelligence about their customers, unregulated enterprises tend to be knowledge-based, characterized by higher market value than book value. A knowledge-based enterprise gathers data, creates information and develops knowledge by leveraging it as a competitive weapon. It institutionalizes human knowledge as a corporate asset for use over and over again by the use of databases, computer networks, patents, billing, collection and customer services (BCCS), branded interfaces and management capabilities. Activities to become knowledge-based such as replacing inventory/fixed assets with information about material usage to reduce expenditure and achieve more efficient operations, and by focusing on integration and value-adding delivery capabilities, were reviewed

  1. Microbead agglutination based assays

    Kodzius, Rimantas

    2013-01-21

    We report a simple and rapid room temperature assay for point-of-care (POC) testing that is based on specific agglutination. Agglutination tests are based on aggregation of microbeads in the presence of a specific analyte thus enabling the macroscopic observation. Such tests are most often used to explore antibody-antigen reactions. Agglutination has been used for protein assays using a biotin/streptavidin system as well as a hybridization based assay. The agglutination systems are prone to selftermination of the linking analyte, prone to active site saturation and loss of agglomeration at high analyte concentrations. We investigated the molecular target/ligand interaction, explaining the common agglutination problems related to analyte self-termination, linkage of the analyte to the same bead instead of different microbeads. We classified the agglutination process into three kinds of assays: a two- component assay, a three-component assay and a stepped three- component assay. Although we compared these three kinds of assays for recognizing DNA and protein molecules, the assay can be used for virtually any molecule, including ions and metabolites. In total, the optimized assay permits detecting analytes with high sensitivity in a short time, 5 min, at room temperature. Such a system is appropriate for POC testing.

  2. As bases do petismo

    David Samuels

    2004-10-01

    Full Text Available A partir dos dados do ESEB de 2002 o autor realiza um estudo das bases eleitorais do PT e de hipóteses sobre a natureza do petismo. Através de técnicas estatísticas multivariadas, são testadas relações do petismo com variáveis demográficas, socioeconômicas e variáveis relativas a questões políticas específicas. Os resultados apontam que apenas a escolaridade tem uma associação específica com o petismo, com implicações para o seu comportamento sócio-político.Based on the results of the 2002 Brazilian Electoral Study, the author analyses the electoral bases of the Worker´s Party and the factors associated with the "petismo". The relationships between the "petismo"and the socioeconomic, demographic and political variables are tested using multivariate analysis. The results indicate that the only "social category"associated with "petismo"is level of education, and it has clear implications to their social and political behavior.

  3. Value-based genomics.

    Gong, Jun; Pan, Kathy; Fakih, Marwan; Pal, Sumanta; Salgia, Ravi

    2018-03-20

    Advancements in next-generation sequencing have greatly enhanced the development of biomarker-driven cancer therapies. The affordability and availability of next-generation sequencers have allowed for the commercialization of next-generation sequencing platforms that have found widespread use for clinical-decision making and research purposes. Despite the greater availability of tumor molecular profiling by next-generation sequencing at our doorsteps, the achievement of value-based care, or improving patient outcomes while reducing overall costs or risks, in the era of precision oncology remains a looming challenge. In this review, we highlight available data through a pre-established and conceptualized framework for evaluating value-based medicine to assess the cost (efficiency), clinical benefit (effectiveness), and toxicity (safety) of genomic profiling in cancer care. We also provide perspectives on future directions of next-generation sequencing from targeted panels to whole-exome or whole-genome sequencing and describe potential strategies needed to attain value-based genomics.

  4. Nanoplatform-based molecular imaging

    Chen, Xiaoyuan

    2011-01-01

    "Nanoplathform-Based Molecular Imaging provides rationale for using nanoparticle-based probes for molecular imaging, then discusses general strategies for this underutilized, yet promising, technology...

  5. Polyolefin-Based Aerogels

    Lee, Je Kyun; Gould, George

    2012-01-01

    An organic polybutadiene (PB) rubberbased aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection, exhibiting the flexibility, resiliency, toughness, and durability typical of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. The rubbery behaviors of the PB rubber-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogel insulation materials. Additionally, with higher content of hydrogen in their structure, the PB rubber aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. Since PB rubber aerogels also exhibit good hydrophobicity due to their hydrocarbon molecular structure, they will provide better performance reliability and durability as well as simpler, more economic, and environmentally friendly production over the conventional silica or other inorganic-based aerogels, which require chemical treatment to make them hydrophobic. Inorganic aerogels such as silica aerogels demonstrate many unusual and useful properties. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven one promising approach, providing a conveniently fielded form factor that is relatively robust toward handling in industrial environments compared to silica aerogel monoliths. However, the flexible silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain applications. Although the cross-linked organic aerogels such as resorcinol-formaldehyde (RF), polyisocyanurate, and cellulose aerogels show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient

  6. Characteristics Data Base

    Lewis, E.D.; Moore, R.S. (Automated Sciences Group, Inc., Oak Ridge, TN (USA))

    1990-08-01

    The LWR Serial Numbers Database System (SNDB) contains detailed data about individual, historically discharged LWR spent fuel assemblies. This data includes the reactor where used, the year the assemblies were discharged, the pool where they are currently stored, assembly type, burnup, weight, enrichment, and an estimate of their radiological properties. This information is distributed on floppy disks to users in the nuclear industry to assist in planning for the permanent nuclear waste repository. This document describes the design and development of the SNDB. It provides a complete description of the file structures and an outline of the major code modules. It serves as a reference for a programmer maintaining the system, or for others interested in the technical detail of this database. This is the initial version of the SNDB. It contains historical data through December 31, 1987, obtained from the Energy Information Administration (EIA). EIA obtains the data from the utility companies via the RW-859 Survey Form. It evaluates and standardizes the data and distributes the resulting batch level database as a large file on magnetic tape. The Characteristics Data Base obtains this database for use in the LWR Quantities Data Base. Additionally, the CDB obtains the individual assembly level detail from EIA for use in the SNDB. While the Quantities Data Base retains only the level of detail necessary for its reporting, the SNDB does retain and use the batch level data to assist in the identification of a particular assembly serial number. We expect to update the SNDB on an annual basis, as new historical data becomes available.

  7. Vision-based interaction

    Turk, Matthew

    2013-01-01

    In its early years, the field of computer vision was largely motivated by researchers seeking computational models of biological vision and solutions to practical problems in manufacturing, defense, and medicine. For the past two decades or so, there has been an increasing interest in computer vision as an input modality in the context of human-computer interaction. Such vision-based interaction can endow interactive systems with visual capabilities similar to those important to human-human interaction, in order to perceive non-verbal cues and incorporate this information in applications such

  8. Knowledge based Entrepreneurship

    Heebøll, John

    This book is dedicated enterprising people with a technical or a scientific background who consider commercializing ideas and inventions within their field of expertise via a new business activity or a new company. It aims at distilling experiences from many successful and not so successful start......-up ventures from the Technical University of Denmark, 1988 – 2008 into practical, portable knowledge that can be used by future knowledge-based entrepreneurs to set up new companies efficiently or to stay away from it; to do what’s needed and avoid the pitfalls....

  9. Polymerization Using Phosphazene Bases

    Zhao, Junpeng

    2015-09-01

    In the recent rise of metal-free polymerization techniques, organic phosphazene superbases have shown their remarkable strength as promoter/catalyst for the anionic polymerization of various types of monomers. Generally, the complexation of phosphazene base with the counterion (proton or lithium cation) significantly improves the nucleophilicity of the initiator/chain end resulting in highly enhanced polymerization rates, as compared with conventional metalbased initiating systems. In this chapter, the general features of phosphazenepromoted/catalyzed polymerizations and the applications in macromolecular engineering (synthesis of functionalized polymers, block copolymers, and macromolecular architectures) are discussed with challenges and perspectives being pointed out.

  10. Web Based Customized Design

    Moi, Morten Benestad

    2013-01-01

    This thesis studies the methods needed to create a web based application to remotely customize a CAD model. This includes customizing a CAD model by using a graphical user interface to be able to remotely control the inputs to- and outputs from the model in NX, and to get the result sent back to the user. Using CAD systems such as NX requires intensive training, is often a slow process and gives a lot of room for errors. An intuitive, simple user interface will eliminate the need for CAD trai...

  11. Location-based games

    Ejsing-Duun, Stine

    In this dissertation, it is explored which prerequisites are necessary in location-based games (LBGs) to make meaningful the meeting between players and spatiality with an emphasis on physical locations. Throughout the dissertation, it has been shown that LBGs affect players’ perception of and be...... possible. The practical contribution is my creation of the LBG Visions of Sara. People continue to play this game in Odense more than two years after its launch, and DJEEO uses it as a showcase, enabling the company to sell similar LBGs....

  12. LIGHTWEIGHT CONCRETE BASED GRANSHLAK

    NETESA M. I.

    2016-02-01

    Full Text Available Raising of problem. Concrete advisable to obtain a low strength with local secondary resources for recycling and reduce the environmental burden on the environment. But it is important to design such concrete compositions with a reduced flow of cement. It is known that the coefficient of efficiency of use of cement in the concrete of the heavy and B10 is less than about 0.5, which is almost two times smaller than in class B15 concrete and above. Even lower coefficient of efficiency in light concrete cement low strength. Therefore, it is important to find patterns determining the composition of lightweight concrete based on local-products industry with more efficient use of cement in them. Purpose.. Based on the analysis of earlier research results, including with the use of methods of mathematical planning of experiments to determine the concrete contents, which can provide the requirements for the underlying layers of the floor, the compressive strength of which should correspond to the class B5. It is important to provide the required strength at minimum flow of the cement, which is the most expensive and energy-intensive part of concrete. Conclusion. Analysis of the test results of control samples of concrete in 28-day-old, the following laws. The required tensile strength of concrete compressive strength of 7.0 MPa can be obtained in the test range when used in formulations as a filler as the Dnieper hydroelectric power station fly ash and tailings Krivoy Rog iron ore YuGOK. To ensure providing the required characteristic strength of the concrete in the underlying layers of the floor is advisable to use a nominal composition per cubic meter of concrete: cement 160 kg granshlaka Plant named after Petrovsky, 675 kg of fly ash Dnieper HPP 390 kg, 400 kg of sand, 230 liters of water. Thus, while ensuring rational grain composition components can obtain the desired strength lightweight concrete based granshlaka plant Petrovsky, using as fillers

  13. Accelerator-based BNCT.

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. © 2013 Elsevier Ltd. All rights reserved.

  14. Cellular based cancer vaccines

    Hansen, M; Met, Ö; Svane, I M

    2012-01-01

    Cancer vaccines designed to re-calibrate the existing host-tumour interaction, tipping the balance from tumor acceptance towards tumor control holds huge potential to complement traditional cancer therapies. In general, limited success has been achieved with vaccines composed of tumor...... to transiently affect in vitro migration via autocrine receptor-mediated endocytosis of CCR7. In the current review, we discuss optimal design of DC maturation focused on pre-clinical as well as clinical results from standard and polarized dendritic cell based cancer vaccines....

  15. WAP - based telemedicine applications

    Hung, K.; Zhang, Y.T.

    2001-01-01

    Telemedicine refers to the utilization of telecommunication technology for medical diagnosis, treatment, and patient care. Its aim is to provide expert-based health care to remote sites through telecommunication and information technologies. The significant advances in technologies have enabled the introduction of a broad range of telemedicine applications, which are supported by computer networks, wireless communication, and information superhighway. For example, some hospitals are using tele-radiology for remote consultation. Such a system includes medical imaging devices networked with computers and databases. Another growing area is patient monitoring, in which sensors are used to acquire biomedical signals, such as electrocardiogram (ECG), blood pressure, and body temperature, from a remote patient, who could be in bed or moving freely. The signals are then relayed to remote systems for viewing and analysis. Telemedicine can be divided into two basic modes of operations: real-time mode, in which the patient data can be accessed remotely in real-time, and store-and-forward mode, in which the acquired data does not have to be accessed immediately. In the recent years, many parties have demonstrated various telemedicine applications based on the Internet and cellular phone as these two fields have been developing rapidly. A current, recognizable trend in telecommunication is the convergence of wireless communication and computer network technologies. This has been reflected in recently developed telemedicine systems. For example, in 1998 J. Reponen, et al. have demonstrated transmission and display of computerized tomography (CT) examinations using a remote portable computer wirelessly connected to a computer network through TCP/IP on a GSM cellular phone. Two years later, they carried out the same tests with a GSM-based wireless personal digital assistant (PDA). The WAP (Wireless Application Protocol) Forum was founded in 1997 to create a global protocol

  16. Mars base buildup scenarios

    Blacic, J.D.

    1985-01-01

    Two surface base build-up scenarios are presented in order to help visualize the mission and to serve as a basis for trade studies. In the first scenario, direct manned landings on the Martian surface occur early in the missions and scientific investigation is the main driver and rationale. In the second scenario, early development of an infrastructure to exploite the volatile resources of the Martian moons for economic purposes is emphasized. Scientific exploration of the surface is delayed at first, but once begun develops rapidly aided by the presence of a permanently manned orbital station

  17. Agent-Based Optimization

    Jędrzejowicz, Piotr; Kacprzyk, Janusz

    2013-01-01

    This volume presents a collection of original research works by leading specialists focusing on novel and promising approaches in which the multi-agent system paradigm is used to support, enhance or replace traditional approaches to solving difficult optimization problems. The editors have invited several well-known specialists to present their solutions, tools, and models falling under the common denominator of the agent-based optimization. The book consists of eight chapters covering examples of application of the multi-agent paradigm and respective customized tools to solve  difficult optimization problems arising in different areas such as machine learning, scheduling, transportation and, more generally, distributed and cooperative problem solving.

  18. Refractive index based measurements

    2014-01-01

    In a method for performing a refractive index based measurement of a property of a fluid such as chemical composition or temperature by observing an apparent angular shift in an interference fringe pattern produced by back or forward scattering interferometry, ambiguities in the measurement caused...... by the apparent shift being consistent with one of a number of numerical possibilities for the real shift which differ by 2n are resolved by combining measurements performed on the same sample using light paths therethrough of differing lengths....

  19. Sustainability Base Construction Update

    Mewhinney, Michael

    2012-01-01

    Construction of the new Sustainability Base Collaborative support facility, expected to become the highest performing building in the federal government continues at NASA's Ames Research Center, Moffet Field, Calif. The new building is designed to achieve a platinum rating under the leadership in Energy and Environment Design (LEED) new construction standards for environmentally sustainable construction developed by the U. S. Green Building Council, Washington, D. C. When completed by the end of 2011, the $20.6 million building will feature near zero net energy consumption, use 90 percent less potable water than conventionally build buildings of equivalent size, and will result in reduced building maintenance costs.

  20. Chitosan-based nanocomposites

    Kesavan Pillai, Sreejarani

    2012-08-01

    Full Text Available , and hygiene devices. They thus represent a strong and emerging answer for improved and eco-friendly materials. This chapter reviews the recent developments in the area of chitosan-based nanocomposites, with a special emphasis on clay-containing nanocomposites...-sized mineral fillers like silica, talc, and clay are added to reduce the cost and improve chitosan’s performance in some way. However, the mechanical properties such as elongation at break and tensile strength of these composites decrease with the incorporation...

  1. Droplet based microfluidics

    Seemann, Ralf; Brinkmann, Martin; Pfohl, Thomas; Herminghaus, Stephan

    2012-01-01

    Droplet based microfluidics is a rapidly growing interdisciplinary field of research combining soft matter physics, biochemistry and microsystems engineering. Its applications range from fast analytical systems or the synthesis of advanced materials to protein crystallization and biological assays for living cells. Precise control of droplet volumes and reliable manipulation of individual droplets such as coalescence, mixing of their contents, and sorting in combination with fast analysis tools allow us to perform chemical reactions inside the droplets under defined conditions. In this paper, we will review available drop generation and manipulation techniques. The main focus of this review is not to be comprehensive and explain all techniques in great detail but to identify and shed light on similarities and underlying physical principles. Since geometry and wetting properties of the microfluidic channels are crucial factors for droplet generation, we also briefly describe typical device fabrication methods in droplet based microfluidics. Examples of applications and reaction schemes which rely on the discussed manipulation techniques are also presented, such as the fabrication of special materials and biophysical experiments.

  2. DVD Based Electronic Pulser

    Morris, Scott J.; Pratt, Rick M.; Hughes, Michael A.; Kouzes, Richard T.; Pitts, W K.; Robinson, Eric E.

    2005-01-01

    This paper describes the design, construction, and testing of a DVD based electronic pulser system (DVDEPS). Such a device is used to generate pulse streams for simulation of both gamma and neutron detector systems. The DVDEPS reproduces a random pulse stream of a full HPGe spectrum as well as a digital pulse stream representing the output of a neutron multiplicity detector. The exchangeable DVD media contains over an hour of data for both detector systems and can contain an arbitrary gamma spectrum and neutron pulse stream. The data is written to the DVD using a desktop computer program from either actual or simulated spectra. The targeted use of the DVDEPS is authentication or validation of monitoring equipment for non-proliferation purposes, but it is also of general use whenever a complex data stream is required. The DVD based pulser combines the storage capacity and simplicity of DVD technology with commonly available electronic components to build a relatively inexpensive yet highly capable testing instrument

  3. Evidence-based surgery

    Miran Rems

    2007-04-01

    Full Text Available Background: Surgery is setting a new ground by the reign of evidence that was brought up by the Evidence Based Medicine (EBM. While experiences and opinion of an expert count the least by the principles of EBM, randomized controlled trials (RCT and other comparative studies have gained their importance. Recommendations that were included in guidelines represent a demanding shift in surgeon’s professional thinking. Their thinking and classical education have not yet been completely based on the results of such studies and are still very very much master-pupil centred. Assessment of someone’s own experiences is threatened by objectivity as negative experiences get recorded in deeper memory. Randomized studies and meta-analyses do appear also in surgery. However, they demand an extra knowledge about critical assessment.Conclusions: Setting a patient to the foreground brings a surgeon’s decision to the field of EBM. The process has already begun and cannot be avoided. Decision hierarchy moves from the experience field to the evidence territory but to a lesser extent when compared to the rest of medicine. There exist objective restrictions with approving a new paradigm. However, these should not stop the process of EBM implementation. Finally, there is an ethic issue to be considered. Too slow activities in research, education and critical assessment can bring the surgeon to the position when a well-informed patient loses his/her trust.

  4. Microlaser-based displays

    Bergstedt, Robert; Fink, Charles G.; Flint, Graham W.; Hargis, David E.; Peppler, Philipp W.

    1997-07-01

    Laser Power Corporation has developed a new type of projection display, based upon microlaser technology and a novel scan architecture, which provides the foundation for bright, extremely high resolution images. A review of projection technologies is presented along with the limitations of each and the difficulties they experience in trying to generate high resolution imagery. The design of the microlaser based projector is discussed along with the advantage of this technology. High power red, green, and blue microlasers have been designed and developed specifically for use in projection displays. These sources, in combination with high resolution, high contrast modulator, produce a 24 bit color gamut, capable of supporting the full range of real world colors. The new scan architecture, which reduces the modulation rate and scan speeds required, is described. This scan architecture, along with the inherent brightness of the laser provides the fundamentals necessary to produce a 5120 by 4096 resolution display. The brightness and color uniformity of the display is excellent, allowing for tiling of the displays with far fewer artifacts than those in a traditionally tiled display. Applications for the display include simulators, command and control centers, and electronic cinema.

  5. SPACE BASED INTERCEPTOR SCALING

    G. CANAVAN

    2001-02-01

    Space Based Interceptor (SBI) have ranges that are adequate to address rogue ICBMs. They are not overly sensitive to 30-60 s delay times. Current technologies would support boost phase intercept with about 150 interceptors. Higher acceleration and velocity could reduce than number by about a factor of 3 at the cost of heavier and more expensive Kinetic Kill Vehicles (KKVs). 6g SBI would reduce optimal constellation costs by about 35%; 8g SBI would reduce them another 20%. Interceptor ranges fall rapidly with theater missile range. Constellations increase significantly for ranges under 3,000 km, even with advanced interceptor technology. For distributed launches, these estimates recover earlier strategic scalings, which demonstrate the improved absentee ratio for larger or multiple launch areas. Constellations increase with the number of missiles and the number of interceptors launched at each. The economic estimates above suggest that two SBI per missile with a modest midcourse underlay is appropriate. The SBI KKV technology would appear to be common for space- and surface-based boost phase systems, and could have synergisms with improved midcourse intercept and discrimination systems. While advanced technology could be helpful in reducing costs, particularly for short range theater missiles, current technology appears adequate for pressing rogue ICBM, accidental, and unauthorized launches.

  6. Challenge Based Innovation gala

    CERN. Geneva; Utriainen, Tuuli Maria; Toivonen, Harri; Nordberg, Markus

    2014-01-01

    Challenge Based Innovation gala   There’s a new experiment starting in CERN called IdeaLab where we work together with detector R&D researchers to help them to bridge their knowledge into a more human, societally oriented context. Currently we are located in B153, but will move our activities to a new facility next to the Globe in May 2014. One of our first pilot projects is a 5 month course CBI (Challenge Based Innovation) where two multidisciplinary student teams join forces with Edusafe & TALENT projects at CERN. Their goal is to discover what kind of tools for learning could be created in collaboration with the two groups. After months of user interviews and low resolution prototyping they are ready to share the results with us in the form of an afternoon gala. We warmly welcome you to join us to see the students' results and experience the prototypes they have conceived. The event is in three parts, you are welcome to visit all of them,...

  7. [Competence based medical education].

    Bernabó, Jorge G; Buraschi, Jorge; Olcese, Juan; Buraschi, María; Duro, Eduardo

    2007-01-01

    The strategy of curriculum planning in the majority of the Schools of Medicine has shifted, in the past years, from curriculum models based in contents to outcome oriented curricula. Coincidently the interest in defining and evaluating the clinical competences that a graduate must have has grown. In our country, and particularly in the Associated Hospitals belonging to the Unidad Regional de Enseñanza IV of the UBA School of Medicine, evidence has been gathered showing that the acquisition of clinical competences during the grade is in general insufficient. The foundations and characteristics of PREM (Programa de Requisitos Esenciales Mínimos) are described. PREM is a tool to promote the apprenticeship of abilities and necessary skills for the practice of medicine. The objective of the program is to promote the apprenticeship of a well defined list of core competences considered indispensable for a general practitioner. An outcome oriented curriculum with a clear definition of the expected knowledge, skills and attitudes of a graduate of the programme, the promotion of learning experiences centered in the practice and evaluation tools based in direct observation of the student's performance should contribute to close the gap between what the Medicine Schools traditionally teach and evaluate, and what the doctor needs to know and needs to do to perform correctly its profession.

  8. Constraint-based reachability

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  9. Metasurface-Based Polarimeters

    Fei Ding

    2018-04-01

    Full Text Available The state of polarization (SOP is an inherent property of light that can be used to gain crucial information about the composition and structure of materials interrogated with light. However, the SOP is difficult to experimentally determine since it involves phase information between orthogonal polarization states, and is uncorrelated with the light intensity and frequency, which can be easily determined with photodetectors and spectrometers. Rapid progress on optical gradient metasurfaces has resulted in the development of conceptually new approaches to the SOP characterization. In this paper, we review the fundamentals of and recent developments within metasurface-based polarimeters. Starting by introducing the concepts of generalized Snell’s law and Stokes parameters, we explain the Pancharatnam–Berry phase (PB-phase which is instrumental for differentiating between orthogonal circular polarizations. Then we review the recent progress in metasurface-based polarimeters, including polarimeters, spectropolarimeters, orbital angular momentum (OAM spectropolarimeters, and photodetector integrated polarimeters. The review is ended with a short conclusion and perspective for future developments.

  10. Risk-based safety indicators

    Szikszai, T.

    1997-01-01

    The presentation discusses the following issues: The objectives of the risk-based indicator programme. The characteristics of the risk-based indicators. The objectives of risk-based safety indicators - in monitoring safety; in PSA applications. What indicators? How to produce the risk based indicators? PSA requirements

  11. MS Based Metabonomics

    Want, Elizabeth J.; Metz, Thomas O.

    2010-03-01

    Metabonomics is the latest and least mature of the systems biology triad, which also includes genomics and proteomics, and has its origins in the early orthomolecular medicine work pioneered by Linus Pauling and Arthur Robinson. It was defined by Nicholson and colleagues in 1999 as the quantitative measurement of perturbations in the metabolite complement of an integrated biological system in response to internal or external stimuli, and is often used today to describe many non-global types of metabolite analyses. Applications of metabonomics are extensive and include toxicology, nutrition, pharmaceutical research and development, physiological monitoring and disease diagnosis. For example, blood samples from millions of neonates are tested routinely by mass spectrometry (MS) as a diagnostic tool for inborn errors of metabolism. The metabonome encompasses a wide range of structurally diverse metabolites; therefore, no single analytical platform will be sufficient. Specialized sample preparation and detection techniques are required, and advances in NMR and MS technologies have led to enhanced metabonome coverage, which in turn demands improved data analysis approaches. The role of MS in metabonomics is still evolving as instrumentation and software becomes more sophisticated and as researchers realize the strengths and limitations of current technology. MS offers a wide dynamic range, high sensitivity, and reproducible, quantitative analysis. These attributes are essential for addressing the challenges of metabonomics, as the range of metabolite concentrations easily exceeds nine orders of magnitude in biofluids, and the diversity of molecular species ranges from simple amino and organic acids to lipids and complex carbohydrates. Additional challenges arise in generating a comprehensive metabolite profile, downstream data processing and analysis, and structural characterization of important metabolites. A typical workflow of MS-based metabonomics is shown in Figure

  12. Skull base tumor model.

    Gragnaniello, Cristian; Nader, Remi; van Doormaal, Tristan; Kamel, Mahmoud; Voormolen, Eduard H J; Lasio, Giovanni; Aboud, Emad; Regli, Luca; Tulleken, Cornelius A F; Al-Mefty, Ossama

    2010-11-01

    Resident duty-hours restrictions have now been instituted in many countries worldwide. Shortened training times and increased public scrutiny of surgical competency have led to a move away from the traditional apprenticeship model of training. The development of educational models for brain anatomy is a fascinating innovation allowing neurosurgeons to train without the need to practice on real patients and it may be a solution to achieve competency within a shortened training period. The authors describe the use of Stratathane resin ST-504 polymer (SRSP), which is inserted at different intracranial locations to closely mimic meningiomas and other pathological entities of the skull base, in a cadaveric model, for use in neurosurgical training. Silicone-injected and pressurized cadaveric heads were used for studying the SRSP model. The SRSP presents unique intrinsic metamorphic characteristics: liquid at first, it expands and foams when injected into the desired area of the brain, forming a solid tumorlike structure. The authors injected SRSP via different passages that did not influence routes used for the surgical approach for resection of the simulated lesion. For example, SRSP injection routes included endonasal transsphenoidal or transoral approaches if lesions were to be removed through standard skull base approach, or, alternatively, SRSP was injected via a cranial approach if the removal was planned to be via the transsphenoidal or transoral route. The model was set in place in 3 countries (US, Italy, and The Netherlands), and a pool of 13 physicians from 4 different institutions (all surgeons and surgeons in training) participated in evaluating it and provided feedback. All 13 evaluating physicians had overall positive impressions of the model. The overall score on 9 components evaluated--including comparison between the tumor model and real tumor cases, perioperative requirements, general impression, and applicability--was 88% (100% being the best possible

  13. Plasma based accelerators

    Caldwell, Allen [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2015-05-01

    The concept of laser-induced plasma wakefields as a technique to accelerate charged particles was introduced 35 years ago as a means to go beyond the accelerating gradients possible with metallic cavities supporting radio frequency electromagnetic fields. Significant developments in laser technology have made possible the pulse intensity needed to realize this concept, and rapid progress is now underway in the realization of laser-driven plasma wakefield acceleration. It has also been realized that similar accelerating gradients can be produced by particle beams propagating in plasmas, and experimental programs have also been undertaken to study this possibility. Positive results have been achieved with electron-driven plasma wakefields, and a demonstration experiment with proton-driven wakefields is under construction at CERN. The concepts behind these different schemes and their pros and cons are described, as well as the experimental results achieved. An outlook for future practical uses of plasma based accelerators will also be given.

  14. Gossip-Based Broadcast

    Leitão, João; Pereira, José; Rodrigues, Luís

    Gossip, or epidemic, protocols have emerged as a powerful strategy to implement highly scalable and resilient reliable broadcast primitives on large scale peer-to-peer networks. Epidemic protocols are scalable because they distribute the load among all nodes in the system and resilient because they have an intrinsic level of redundancy that masks node and network failures. This chapter provides an introduction to gossip-based broadcast on large-scale unstructured peer-to-peer overlay networks: it surveys the main results in the field, discusses techniques to build and maintain the overlays that support efficient dissemination strategies, and provides an in-depth discussion and experimental evaluation of two concrete protocols, named HyParView and Plumtree.

  15. Sensory bases of navigation.

    Gould, J L

    1998-10-08

    Navigating animals need to know both the bearing of their goal (the 'map' step), and how to determine that direction (the 'compass' step). Compasses are typically arranged in hierarchies, with magnetic backup as a last resort when celestial information is unavailable. Magnetic information is often essential to calibrating celestial cues, though, and repeated recalibration between celestial and magnetic compasses is important in many species. Most magnetic compasses are based on magnetite crystals, but others make use of induction or paramagnetic interactions between short-wavelength light and visual pigments. Though odors may be used in some cases, most if not all long-range maps probably depend on magnetite. Magnetitebased map senses are used to measure only latitude in some species, but provide the distance and direction of the goal in others.

  16. Graphene based biosensors

    Gürel, Hikmet Hakan, E-mail: hhakan.gurel@kocaeli.edu.tr [Kocaeli University, Kocaeli (Turkey); Salmankurt, Bahadır [Sakarya University, Sakarya (Turkey)

    2016-03-25

    Nanometer-sized graphene as a 2D material has unique chemical and electronic properties. Because of its unique physical, chemical, and electronic properties, its interesting shape and size make it a promising nanomaterial in many biological applications. It is expected that biomaterials incorporating graphene will be developed for the graphene-based drug delivery systems and biomedical devices. The interactions of biomolecules and graphene are long-ranged and very weak. Development of new techniques is very desirable for design of bioelectronics sensors and devices. In this work, we present first-principles calculations within density functional theory to calculate effects of charging on nucleobases on graphene. It is shown that how modify structural and electronic properties of nucleobases on graphene by applied charging.

  17. Integrated data base program

    Notz, K.J.

    1981-01-01

    The IDB Program provides direct support to the DOE Nuclear Waste Management and Fuel Cycle Programs and their lead sites and support contractors by providing and maintaining a current, integrated data base of spent fuel and radioactive waste inventories and projections. All major waste types (HLW, TRU, and LLW) and sources (government, commerical fuel cycle, and I/I) are included. A major data compilation was issued in September, 1981: Spent Fuel and Radioactive Waste Inventories and Projections as of December 31, 1980, DOE/NE-0017. This report includes chapters on Spent Fuel, HLW, TRU Waste, LLW, Remedial Action Waste, Active Uranium Mill Tailings, and Airborne Waste, plus Appendices with more detailed data in selected areas such as isotopics, radioactivity, thermal power, projections, and land usage. The LLW sections include volumes, radioactivity, thermal power, current inventories, projected inventories and characteristics, source terms, land requirements, and a breakdown in terms of government/commercial and defense/fuel cycle/I and I

  18. Nickel base alloys

    Gibson, R.C.; Korenko, M.K.

    1980-01-01

    Nickel based alloy, the characteristic of which is that it mainly includes in percentages by weight: 57-63 Ni, 7-18 Cr, 10-20 Fe, 4-6 Mo, 1-2 Nb, 0.2-0.8 Si, 0.01-0.05 Zr, 1.0-2.5 Ti, 1.0-2.5 Al, 0.02-0.06 C and 0.002-0.015 B. The aim is to create new nickel-chromium alloys, hardened in a solid solution and by precipitation, that are stable, exhibit reduced swelling and resistant to plastic deformation inside the reactor. These alloys of the gamma prime type have improved mechanical strengthm swelling resistance, structural stability and welding properties compared with Inconel 625 [fr

  19. Rate based failure detection

    Johnson, Brett Emery Trabun; Gamage, Thoshitha Thanushka; Bakken, David Edward

    2018-01-02

    This disclosure describes, in part, a system management component and failure detection component for use in a power grid data network to identify anomalies within the network and systematically adjust the quality of service of data published by publishers and subscribed to by subscribers within the network. In one implementation, subscribers may identify a desired data rate, a minimum acceptable data rate, desired latency, minimum acceptable latency and a priority for each subscription. The failure detection component may identify an anomaly within the network and a source of the anomaly. Based on the identified anomaly, data rates and or data paths may be adjusted in real-time to ensure that the power grid data network does not become overloaded and/or fail.

  20. Behavior based safety

    Sudhikumaran, T.V.; Mehta, S.C.; Goyal, D.K.

    2009-01-01

    Behaviour Based Safety (popularly known as BBS) is a new methodology for achieving injury free work place and total Safety Culture. BBS is successfully being implemented and is being practiced as a work methodology for achieving a loss and injury free work environment and work practice. Through BBS, it was brought out that the root causes of all Industrial accidents some how originate from the 'at risk' behaviour of some individual or group of individuals at some level. The policy of NPCIL is to excel in the field of Industrial and Fire Safety in comparison to international standards. This article indents to bring out the various parameters helping in installing BBS programme at any plant. (author)

  1. Fuel cycle based safeguards

    De Montmollin, J.M.; Higinbotham, W.A.; Gupta, D.

    1985-07-01

    In NPT safeguards the same model approach and absolute-quantity inspection goals are applied at present to all similar facilities, irrespective of the State's fuel cycle. There is a continuing interest and activity on the part of the IAEA in new NPT safeguards approaches that more directly address a State's nuclear activities as a whole. This fuel cycle based safeguards system is expected to a) provide a statement of findings for the entire State rather than only for individual facilities; b) allocate inspection efforts so as to reflect more realistically the different categories of nuclear materials in the different parts of the fuel cycle and c) provide more timely and better coordinated information on the inputs, outputs and inventories of nuclear materials in a State. (orig./RF) [de

  2. Bases para proyectiles dirigidos

    Editorial, Equipo

    1959-03-01

    Full Text Available Aunque actualmente no se ha llegado a una línea general de métodos o sistemas que gobiernen un tipo característico de rampa y servicios auxiliares necesarios para el lanzamiento al espacio de proyectiles dirigidos a grandes alturas y distancias, las experiencias obtenidas en diferentes ensayos, utilizando distintos tipos de proyectiles y trayectorias balísticas, han sentado toda una serie de procedimientos, datos y conclusiones de gran valor balístico que, aun teniendo en cuenta la continua evolución del proyectil, sus formas, combustibles y alcances, se conocen ya, con bastante aproximación, las condiciones mínimas que ha de reunir una base dedicada a este tipo de lanzamientos.

  3. Situation based housing

    Duelund Mortensen, Peder; Welling, Helen; Wiell Nordberg, Lene

    2007-01-01

    of the average family's lifestyle. These dwellings were ground-breaking when they were built, but today are clearly a product of their time. The reaction to functionalism and the postwar mass production gave rise to flexible dwelling with countless possibilities for room division. The housing of this period has...... characteristics which in the long run have proven to be unfortunate both in terms in terms of durability and architectural quality. Today there is a focus on the development of more open and functionally non-determined housing. A number of new housing schemes in and around Copenhagen reveal a variety...... of approaches to these goals. This working paper reviews not only a selection of new housing types, but also dwellings from the past, which each contain an aspect of changeability. Our study is based on information from users in the selected housing schemes, gathered from questionnaires, information about...

  4. Liaison based assembly design

    Ames, A.; Kholwadwala, D.; Wilson, R.H.

    1996-12-01

    Liaison Based Assembly Design extends the current information infrastructure to support design in terms of kinematic relationships between parts, or liaisons. These liaisons capture information regarding contact, degrees-of-freedom constraints and containment relationships between parts in an assembly. The project involved defining a useful collection of liaison representations, investigating their properties, and providing for maximum use of the data in downstream applications. We tested our ideas by implementing a prototype system involving extensions to Pro/Engineer and the Archimedes assembly planner. With an expanded product model, the design system is more able to capture design intent. When a product update is attempted, increased knowledge availability improves our ability to understand the effect of design changes. Manufacturing and analysis disciplines benefit from having liaison information available, so less time is wasted arguing over incomplete design specifications and our enterprise can be more completely integrated.

  5. Touching base with OPERA

    CERN Bulletin

    2011-01-01

    Three seminars – at CERN, at Gran Sasso and in Japan – and an article calling for the scrutiny of the scientific community: the OPERA Collaboration opened its research publicly. In addition to huge press coverage, this triggered welcome reactions from colleagues around the world, many of whom will attempt to independently interpret and reproduce the measurement. OPERA’s Spokesperson touches base with the Bulletin.   The CERN Main Auditorium was crowded as OPERA Physics co-ordinator Dario Autiero presented the results of their research (23 September 2011). According to the OPERA strategy, the results of the measurements are in the hands of the scientific community and, as for any other scientific result, several months will be needed before other groups will be able to perform an independent measurement. In the meantime, the OPERA Collaboration is dealing with an avalanche of emails from the scientific community, members of the general public, and the press. &...

  6. Pathway-based analyses.

    Kent, Jack W

    2016-02-03

    New technologies for acquisition of genomic data, while offering unprecedented opportunities for genetic discovery, also impose severe burdens of interpretation and penalties for multiple testing. The Pathway-based Analyses Group of the Genetic Analysis Workshop 19 (GAW19) sought reduction of multiple-testing burden through various approaches to aggregation of highdimensional data in pathways informed by prior biological knowledge. Experimental methods testedincluded the use of "synthetic pathways" (random sets of genes) to estimate power and false-positive error rate of methods applied to simulated data; data reduction via independent components analysis, single-nucleotide polymorphism (SNP)-SNP interaction, and use of gene sets to estimate genetic similarity; and general assessment of the efficacy of prior biological knowledge to reduce the dimensionality of complex genomic data. The work of this group explored several promising approaches to managing high-dimensional data, with the caveat that these methods are necessarily constrained by the quality of external bioinformatic annotation.

  7. Refractive index based measurements

    2014-01-01

    A refractive index based measurement of a property of a fluid is measured in an apparatus comprising a variable wavelength coherent light source (16), a sample chamber (12), a wavelength controller (24), a light sensor (20), a data recorder (26) and a computation apparatus (28), by - directing...... coherent light having a wavelength along an input light path, - producing scattering of said light from each of a plurality of interfaces within said apparatus including interfaces between said fluid and a surface bounding said fluid, said scattering producing an interference pattern formed by said...... scattered light, - cyclically varying the wavelength of said light in said input light path over a 1 nm to 20nm wide range of wavelengths a rate of from 10Hz to 50 KHz, - recording variation of intensity of the interfering light with change in wavelength of the light at an angle of observation...

  8. Transaction based approach

    Hunka, Frantisek; Matula, Jiri

    2017-07-01

    Transaction based approach is utilized in some methodologies in business process modeling. Essential parts of these transactions are human beings. The notion of agent or actor role is usually used for them. The paper on a particular example describes possibilities of Design Engineering Methodology for Organizations (DEMO) and Resource-Event-Agent (REA) methodology. Whereas the DEMO methodology can be regarded as a generic methodology having its foundation in the theory of Enterprise Ontology the REA methodology is regarded as the domain specific methodology and has its origin in accountancy systems. The results of these approaches is that the DEMO methodology captures everything that happens in the reality with a good empirical evidence whereas the REA methodology captures only changes connected with economic events. Economic events represent either change of the property rights to economic resource or consumption or production of economic resources. This results from the essence of economic events and their connection to economic resources.

  9. Pitch Based Sound Classification

    Nielsen, Andreas Brinch; Hansen, Lars Kai; Kjems, U

    2006-01-01

    A sound classification model is presented that can classify signals into music, noise and speech. The model extracts the pitch of the signal using the harmonic product spectrum. Based on the pitch estimate and a pitch error measure, features are created and used in a probabilistic model with soft......-max output function. Both linear and quadratic inputs are used. The model is trained on 2 hours of sound and tested on publicly available data. A test classification error below 0.05 with 1 s classification windows is achieved. Further more it is shown that linear input performs as well as a quadratic......, and that even though classification gets marginally better, not much is achieved by increasing the window size beyond 1 s....

  10. Telephone-Based Coaching.

    Boccio, Mindy; Sanna, Rashel S; Adams, Sara R; Goler, Nancy C; Brown, Susan D; Neugebauer, Romain S; Ferrara, Assiamira; Wiley, Deanne M; Bellamy, David J; Schmittdiel, Julie A

    2017-03-01

    Many Americans continue to smoke, increasing their risk of disease and premature death. Both telephone-based counseling and in-person tobacco cessation classes may improve access for smokers seeking convenient support to quit. Little research has assessed whether such programs are effective in real-world clinical populations. Retrospective cohort study comparing wellness coaching participants with two groups of controls. Kaiser Permanente Northern California, a large integrated health care delivery system. Two hundred forty-one patients who participated in telephonic tobacco cessation coaching from January 1, 2011, to March 31, 2012, and two control groups: propensity-score-matched controls, and controls who participated in a tobacco cessation class during the same period. Wellness coaching participants received an average of two motivational interviewing-based coaching sessions that engaged the patient, evoked their reason to consider quitting, and helped them establish a quit plan. Self-reported quitting of tobacco and fills of tobacco cessation medications within 12 months of follow-up. Logistic regressions adjusting for age, gender, race/ethnicity, and primary language. After adjusting for confounders, tobacco quit rates were higher among coaching participants vs. matched controls (31% vs. 23%, p Coaching participants and class attendees filled tobacco-cessation prescriptions at a higher rate (47% for both) than matched controls (6%, p coaching was as effective as in-person classes and was associated with higher rates of quitting compared to no treatment. The telephonic modality may increase convenience and scalability for health care systems looking to reduce tobacco use and improve health.

  11. Model Based Temporal Reasoning

    Rabin, Marla J.; Spinrad, Paul R.; Fall, Thomas C.

    1988-03-01

    Systems that assess the real world must cope with evidence that is uncertain, ambiguous, and spread over time. Typically, the most important function of an assessment system is to identify when activities are occurring that are unusual or unanticipated. Model based temporal reasoning addresses both of these requirements. The differences among temporal reasoning schemes lies in the methods used to avoid computational intractability. If we had n pieces of data and we wanted to examine how they were related, the worst case would be where we had to examine every subset of these points to see if that subset satisfied the relations. This would be 2n, which is intractable. Models compress this; if several data points are all compatible with a model, then that model represents all those data points. Data points are then considered related if they lie within the same model or if they lie in models that are related. Models thus address the intractability problem. They also address the problem of determining unusual activities if the data do not agree with models that are indicated by earlier data then something out of the norm is taking place. The models can summarize what we know up to that time, so when they are not predicting correctly, either something unusual is happening or we need to revise our models. The model based reasoner developed at Advanced Decision Systems is thus both intuitive and powerful. It is currently being used on one operational system and several prototype systems. It has enough power to be used in domains spanning the spectrum from manufacturing engineering and project management to low-intensity conflict and strategic assessment.

  12. Mainstreaming gesture based interfaces

    David Procházka

    2013-01-01

    Full Text Available Gestures are a common way of interaction with mobile devices. They emerged especially with the iPhone production. Gestures in currently used devices are usually based on the original gestures presented by Apple in its iOS (iPhone Operating System. Therefore, there is a wide agreement on the mobile gesture design. In last years, it is possible to see experiments with gesture usage also in the other areas of consumer electronics and computers. The examples can include televisions, large projections etc. These gestures can be marked as spatial or 3D gestures. They are connected with a natural 3D environment rather than with a flat 2D screen. Nevertheless, it is hard to find a comparable design agreement within the spatial gestures. Various projects are based on completely different gesture sets. This situation is confusing for their users and slows down spatial gesture adoption.This paper is focused on the standardization of spatial gestures. The review of projects focused on spatial gesture usage is provided in the first part. The main emphasis is placed on the usability point-of-view. On the basis of our analysis, we argue that the usability is the key issue enabling the wide adoption. The mobile gesture emergence was possible easily because the iPhone gestures were natural. Therefore, it was not necessary to learn them.The design and implementation of our presentation software, which is controlled by gestures, is outlined in the second part of the paper. Furthermore, the usability testing results are provided as well. We have tested our application on a group of users not instructed in the implemented gestures design. These results were compared with the other ones, obtained with our original implementation. The evaluation can be used as the basis for implementation of similar projects.

  13. DNA-based machines.

    Wang, Fuan; Willner, Bilha; Willner, Itamar

    2014-01-01

    The base sequence in nucleic acids encodes substantial structural and functional information into the biopolymer. This encoded information provides the basis for the tailoring and assembly of DNA machines. A DNA machine is defined as a molecular device that exhibits the following fundamental features. (1) It performs a fuel-driven mechanical process that mimics macroscopic machines. (2) The mechanical process requires an energy input, "fuel." (3) The mechanical operation is accompanied by an energy consumption process that leads to "waste products." (4) The cyclic operation of the DNA devices, involves the use of "fuel" and "anti-fuel" ingredients. A variety of DNA-based machines are described, including the construction of "tweezers," "walkers," "robots," "cranes," "transporters," "springs," "gears," and interlocked cyclic DNA structures acting as reconfigurable catenanes, rotaxanes, and rotors. Different "fuels", such as nucleic acid strands, pH (H⁺/OH⁻), metal ions, and light, are used to trigger the mechanical functions of the DNA devices. The operation of the devices in solution and on surfaces is described, and a variety of optical, electrical, and photoelectrochemical methods to follow the operations of the DNA machines are presented. We further address the possible applications of DNA machines and the future perspectives of molecular DNA devices. These include the application of DNA machines as functional structures for the construction of logic gates and computing, for the programmed organization of metallic nanoparticle structures and the control of plasmonic properties, and for controlling chemical transformations by DNA machines. We further discuss the future applications of DNA machines for intracellular sensing, controlling intracellular metabolic pathways, and the use of the functional nanostructures for drug delivery and medical applications.

  14. Base Research Program

    Everett Sondreal; John Hendrikson

    2009-03-31

    In June 2009, the Energy & Environmental Research Center (EERC) completed 11 years of research under the U.S. Department of Energy (DOE) Base Cooperative Agreement No. DE-FC26-98FT40320 funded through the Office of Fossil Energy (OFE) and administered at the National Energy Technology Laboratory (NETL). A wide range of diverse research activities were performed under annual program plans approved by NETL in seven major task areas: (1) resource characterization and waste management, (2) air quality assessment and control, (3) advanced power systems, (4) advanced fuel forms, (5) value-added coproducts, (6) advanced materials, and (7) strategic studies. This report summarizes results of the 67 research subtasks and an additional 50 strategic studies. Selected highlights in the executive summary illustrate the contribution of the research to the energy industry in areas not adequately addressed by the private sector alone. During the period of performance of the agreement, concerns have mounted over the impact of carbon emissions on climate change, and new programs have been initiated by DOE to ensure that fossil fuel resources along with renewable resources can continue to supply the nation's transportation fuel and electric power. The agreement has addressed DOE goals for reductions in CO{sub 2} emissions through efficiency, capture, and sequestration while expanding the supply and use of domestic energy resources for energy security. It has further contributed to goals for near-zero emissions from highly efficient coal-fired power plants; environmental control capabilities for SO{sub 2}, NO{sub x}, fine respirable particulate (PM{sub 2.5}), and mercury; alternative transportation fuels including liquid synfuels and hydrogen; and synergistic integration of fossil and renewable resources (e.g., wind-, biomass-, and coal-based electrical generation).

  15. The office based CHIVA

    Passariello F

    2013-09-01

    Full Text Available Fausto Passariello,1 Stefano Ermini,2 Massimo Cappelli,3 Roberto Delfrate,4 Claude Franceschi5 1Centro Diagnostico Aquarius, Napoli, Italy; 2Private Practice, Grassina, Italy; 3Private Practice, Firenze, Italy; 4Casa di Cure Figlie di Maria, Cremona, Italy; 5Hospital St Joseph, Service d'Explorations Vasculaires, Paris, France Abstract: The cure Conservatrice Hémodynamique de l'Insuffisance Veineuse en Ambulatoire (CHIVA can be office based (OB. The OB-CHIVA protocol is aimed at transferring CHIVA procedures to specialists rooms. The protocol will check the feasibility of OB-CHIVA, data pertaining to recurrence, and will offer the opportunity to study saphenous femoral junction (SFJ stump evolution, the role of the washing vessels and the arch recanalization rate, and gather new data about the effect of the length of the treated saphenous vein. A simplified diagnostic procedure will allow an essential ultrasound examination of the venous net while a schematic and easily readable algorithm guides therapeutic choices. The Riobamba draining crossotomy (RDC tactic is composed of a set of OB procedures. While some of these procedures are, at the moment, only proposals, others are already applied. Devices generally used in ablative procedures such as Light Amplification by Stimulated Emission of Radiation (LASER, radio frequency, steam, and mechanical devices are used in this context to serve to conservative interventions for CHIVA. New techniques have also been proposed for devalvulation and tributary disconnection. Detailed follow-up is necessary in order to determine the effects of therapy and possible disease evolution. Finally, information is added about the informed consent and the ethical considerations of OB-CHIVA research. Keywords: CHIVA, office based procedures, LASER, RF, steam

  16. Organic Biochar Based Fertilization

    Schmidt, Hans-Peter; Pandit, Bishnu Hari; Cornelissen, Gerard; Kammann, Claudia

    2017-04-01

    Biochar produced in cost-efficient flame curtain kilns (Kon-Tiki) was nutrient enriched either with cow urine or with dissolved mineral (NPK) fertilizer to produce biochar-based fertilizers containing between 60-100 kg N, 5-60 kg P2O5 and 60-100 kg K2O, respectively, per ton of biochar. In 21 field trials nutrient-enriched biochars were applied at rates of 0.5 to 2 t ha-1 into the root zone of 13 different annual and perennial crops. Treatments combining biochar, compost and organic or chemical fertilizer were evaluated; control treatments contained the same amounts of nutrients but without biochar. All nutrient-enriched biochar substrates improved yields compared to their respective no-biochar controls. Biochar enriched with dissolved NPK produced on average 20% ± 5.1% (N=4) higher yields than standard NPK fertilization without biochar. Cow urine-enriched biochar blended with compost resulted on average in 123% ± 76.7% (N=13) higher yields compared to the organic farmer practice with cow urine-blended compost and outcompeted NPK-enriched biochar (same nutrient dose) by 103% ± 12.4% (N=4) on average. 21 field trials robustly revealed that low-dosage root zone application of organic biochar-based fertilizers caused substantial yield increases in rather fertile silt loam soils compared to traditional organic fertilization and to mineral NPK- or NPK-biochar fertilization. This can likely be explained by the nutrient carrier effect of biochar causing a slow nutrient release behavior, more balanced nutrient fluxes and reduced nutrient losses especially when liquid organic nutrients are used for the biochar enrichment. The results promise new pathways for optimizing organic farming and improving on-farm nutrient cycling.

  17. Loyalty-based management.

    Reichheld, F F

    1993-01-01

    Despite a flurry of activities aimed at serving customers better, few companies have systematically revamped their operations with customer loyalty in mind. Instead, most have adopted improvement programs ad hoc, and paybacks haven't materialized. Building a highly loyal customer base must be integral to a company's basic business strategy. Loyalty leaders like MBNA credit cards are successful because they have designed their entire business systems around customer loyalty--a self-reinforcing system in which the company delivers superior value consistently and reinvents cash flows to find and keep high-quality customers and employees. The economic benefits of high customer loyalty are measurable. When a company consistently delivers superior value and wins customer loyalty, market share and revenues go up, and the cost of acquiring new customers goes down. The better economics mean the company can pay workers better, which sets off a whole chain of events. Increased pay boosts employee moral and commitment; as employees stay longer, their productivity goes up and training costs fall; employees' overall job satisfaction, combined with their experience, helps them serve customers better; and customers are then more inclined to stay loyal to the company. Finally, as the best customers and employees become part of the loyalty-based system, competitors are left to survive with less desirable customers and less talented employees. To compete on loyalty, a company must understand the relationships between customer retention and the other parts of the business--and be able to quantify the linkages between loyalty and profits. It involves rethinking and aligning four important aspects of the business: customers, product/service offering, employees, and measurement systems.

  18. Major Changes in Governmental GAAP.

    Piotrowski, Craig L.

    1988-01-01

    The Governmental Accounting Standards Board (GASB) is the standard-setting body for establishing generally accepted accounting principles for school systems and all state and local governments. A brief summary of a statement prepared by GASB's staff outlines the proposed changes in school accounting and financial reporting. (MLF)

  19. Quantum Confined Semiconductors

    2015-02-01

    scattering mechanisms ( acoustic , piezoelectric, polar and non-polar optical) and the ionized impurity scattering. Since InAs and GaSb are binary... pyrometer referenced at GaSb oxide desorption temperature of 530 C. Figure 6a plots the 10 K carrier densities as a function of Tg. The SLs grown

  20. Foundry based approach for InP based PIC development

    Smit, M.K.

    2014-01-01

    Europe is making significant investments in development of generic photonic foundry platform infrastructures for InP-based and Silicon Photonic ICs. Here we present the present status for the InP-based JePPIX platform.

  1. NMR studies concerning base-base interactions in oligonucleotides

    Hoogen, Y.T. van den.

    1988-01-01

    Two main subjects are treated in the present thesis. The firsst part principally deals with the base-base interactions in single-stranded oligoribonucleotides. The second part presents NMR and model-building studies of DNA and RNA duplexes containing an unpaired base. (author). 242 refs.; 26 figs.; 24 tabs

  2. Computer-based multi-channel analyzer based on internet

    Zhou Xinzhi; Ning Jiaoxian

    2001-01-01

    Combined the technology of Internet with computer-based multi-channel analyzer, a new kind of computer-based multi-channel analyzer system which is based on browser is presented. Its framework and principle as well as its implementation are discussed

  3. Base Camp Architecture

    Warebi Gabriel Brisibe

    2016-03-01

    Full Text Available Longitudinal or time line studies of change in the architecture of a particular culture are common, but an area still open to further research is change across space or place. In particular, there is need for studies on architectural change of cultures stemming from the same ethnic source split between their homeland and other Diasporas. This change may range from minor deviations to drastic shifts away from an architectural norm and the accumulation of these shifts within a time frame constitutes variations. This article focuses on identifying variations in the architecture of the Ijo fishing group that migrates along the coastline of West Africa. It examines the causes of cross-cultural variation between base camp dwellings of Ijo migrant fishermen in the Bakassi Peninsula in Cameroon and Bayelsa State in Nigeria. The study draws on the idea of the inevitability of cultural and social change over time as proposed in the theories of cultural dynamism and evolution. It tests aspects of cultural transmission theory using the principal coordinates analysis to ascertain the possible causes of variation. From the findings, this research argues that migration has enhanced the forces of cultural dynamism, which have resulted in significant variations in the architecture of this fishing group.

  4. Evidence-based management.

    Pfeffer, Jeffrey; Sutton, Robert I

    2006-01-01

    For the most part, managers looking to cure their organizational ills rely on obsolete knowledge they picked up in school, long-standing but never proven traditions, patterns gleaned from experience, methods they happen to be skilled in applying, and information from vendors. They could learn a thing or two from practitioners of evidence-based medicine, a movement that has taken the medical establishment by storm over the past decade. A growing number of physicians are eschewing the usual, flawed resources and are instead identifying, disseminating, and applying research that is soundly conducted and clinically relevant. It's time for managers to do the same. The challenge is, quite simply, to ground decisions in the latest and best knowledge of what actually works. In some ways, that's more difficult to do in business than in medicine. The evidence is weaker in business; almost anyone can (and many people do) claim to be a management expert; and a motley crew of sources--Shakespeare, Billy Graham,Jack Welch, Attila the Hunare used to generate management advice. Still, it makes sense that when managers act on better logic and strong evidence, their companies will beat the competition. Like medicine, management is learned through practice and experience. Yet managers (like doctors) can practice their craft more effectively if they relentlessly seek new knowledge and insight, from both inside and outside their companies, so they can keep updating their assumptions, skills, and knowledge.

  5. Skull base tumors

    Kikinis, R.; Matsumae, M.; Jolesz, F.A.; Black, P.M.; Cline, H.E.; Lorenson, W.E.

    1991-01-01

    This paper reports on an image processing procedure for the planning of surgery of skull base tumors that can extract bone, vessels, tumor, and brain parenchyma and that permits resolution of cranial nerves. Three-dimensional (3D) reconstructions were generated from double-echo long TR interleaved conventional spin-echo and fast-spin-echo MR imaging data. Sixteen cases have been analyzed preoperatively. Image processing consisted of a multistep procedure combining a supervised multivariate analysis with neighborhood operations such as connectivity and erosion/dilation. 3D renderings of anatomic structures of interest were then generated. Cases were evaluated preoperatively and manipulated interactively with the computer-generated images by a team consisting of neuroradiologists, neurosurgeons, and craniofacial surgeons. The preparation of 3D reconstructions required only a few hours and was performed mostly by a research assistant. The preoperative analysis of the 3D reconstructions was found to be a valuable tool, providing information complementing the surgeon's understanding of a case as derived from conventional imaging. The interactive manipulation of data proved to be a powerful way to evaluate alternative surgical approaches

  6. Constraint-based scheduling

    Zweben, Monte

    1993-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  7. Refractory metal based superalloys

    Alonso, Paula R.; Vicente, Eduardo E.; Rubiolo, Gerardo H.

    1999-01-01

    Refractory metals are looked as promising materials for primary circuits in fission reactors and even as fusion reactor components. Indeed, superalloys could be developed which take advantage of their high temperature properties together with the benefits of a two- phase (intermetallic compound-refractory metal matrix) coherent structure. In 1993, researchers of the Office National d'Etudes et de Recherches Aerospatiales of France reported the observation of such a coherent structure in the Ta-Ti-Zr-Al-Nb-Mo system although the exact composition is not reported. The intermetallic compound would be Ti 2 AlMo based. However, the formation of this compound and its possible coexistence with a disordered bcc phase in the ternary system Ti-Al-Mo is a controversial subject in the related literature. In this work we develop a technique to obtain homogeneous alloys samples with 50 Ti-25 Al-25 Mo composition. The resulting specimens were characterized by optical and electronic metallography (SEM), microprobe composition measurements (EPMA) and X-ray diffraction (XRD) analyses. The results show the evidence for a bcc (A2→B2) ordering reaction in the Ti-Al-Mo system in the 50 Ti-25 Al-25 Mo composition. (author)

  8. Fluorescence lifetime based bioassays

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  9. Carbon nanotube based photocathodes

    Hudanski, Ludovic; Minoux, Eric; Schnell, Jean-Philippe; Xavier, Stephane; Pribat, Didier; Legagneux, Pierre; Gangloff, Laurent; Teo, Kenneth B K; Robertson, John; Milne, William I

    2008-01-01

    This paper describes a novel photocathode which is an array of vertically aligned multi-walled carbon nanotubes (MWCNTs), each MWCNT being associated with one p-i-n photodiode. Unlike conventional photocathodes, the functions of photon-electron conversion and subsequent electron emission are physically separated. Photon-electron conversion is achieved with p-i-n photodiodes and the electron emission occurs from the MWCNTs. The current modulation is highly efficient as it uses an optically controlled reconfiguration of the electric field at the MWCNT locations. Such devices are compatible with high frequency and very large bandwidth operation and could lead to their application in compact, light and efficient microwave amplifiers for satellite telecommunication. To demonstrate this new photocathode concept, we have fabricated the first carbon nanotube based photocathode using silicon p-i-n photodiodes and MWCNT bunches. Using a green laser, this photocathode delivers 0.5 mA with an internal quantum efficiency of 10% and an I ON /I OFF ratio of 30

  10. Based on Channel Characteristics

    Zhuo Hao

    2013-01-01

    Full Text Available A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

  11. Biosensors based on cantilevers.

    Alvarez, Mar; Carrascosa, Laura G; Zinoviev, Kiril; Plaza, Jose A; Lechuga, Laura M

    2009-01-01

    Microcantilevers based-biosensors are a new label-free technique that allows the direct detection of biomolecular interactions in a label-less way and with great accuracy by translating the biointeraction into a nanomechanical motion. Low cost and reliable standard silicon technologies are widely used for the fabrication of cantilevers with well-controlled mechanical properties. Over the last years, the number of applications of these sensors has shown a fast growth in diverse fields, such as genomic or proteomic, because of the biosensor flexibility, the low sample consumption, and the non-pretreated samples required. In this chapter, we report a dedicated design and a fabrication process of highly sensitive microcantilever silicon sensors. We will describe as well an application of the device in the environmental field showing the immunodetection of an organic toxic pesticide as an example. The cantilever biofunctionalization process and the subsequent pesticide determination are detected in real time by monitoring the nanometer-scale bending of the microcantilever due to a differential surface stress generated between both surfaces of the device.

  12. Flow-Based Provenance

    Sabah Al-Fedaghi

    2017-02-01

    Full Text Available Aim/Purpose: With information almost effortlessly created and spontaneously available, current progress in Information and Communication Technology (ICT has led to the complication that information must be scrutinized for trustworthiness and provenance. Information systems must become provenance-aware to be satisfactory in accountability, reproducibility, and trustworthiness of data. Background:\tMultiple models for abstract representation of provenance have been proposed to describe entities, people, and activities involved in producing a piece of data, including the Open Provenance Model (OPM and the World Wide Web Consortium. These models lack certain concepts necessary for specifying workflows and encoding the provenance of data products used and generated. Methodology: Without loss of generality, the focus of this paper is on OPM depiction of provenance in terms of a directed graph. We have redrawn several case studies in the framework of our proposed model in order to compare and evaluate it against OPM for representing these cases. Contribution: This paper offers an alternative flow-based diagrammatic language that can form a foundation for modeling of provenance. The model described here provides an (abstract machine-like representation of provenance. Findings: The results suggest a viable alternative in the area of diagrammatic representation for provenance applications. Future Research: Future work will seek to achieve more accurate comparisons with current models in the field.

  13. Communication Base Station Log Analysis Based on Hierarchical Clustering

    Zhang Shao-Hua

    2017-01-01

    Full Text Available Communication base stations generate massive data every day, these base station logs play an important value in mining of the business circles. This paper use data mining technology and hierarchical clustering algorithm to group the scope of business circle for the base station by recording the data of these base stations.Through analyzing the data of different business circle based on feature extraction and comparing different business circle category characteristics, which can choose a suitable area for operators of commercial marketing.

  14. Mindfulness-Based Stress Reduction

    ... R S T U V W X Y Z Mindfulness-Based Stress Reduction (MBSR) Information 6 Things You ... Disease and Dementia (12/20/13) Research Spotlights Mindfulness-Based Stress Reduction, Cognitive-Behavioral Therapy Shown To ...

  15. Risk-based configuration control

    Szikszai, T.

    1997-01-01

    The presentation discusses the following issues: The Configuration Control; The Risk-based Configuration Control (during power operation mode, and during shutdown mode). PSA requirements. Use of Risk-based Configuration Control System. Configuration Management (basic elements, benefits, information requirements)

  16. OLBS: Offline location based services

    Coelho, P; Ana Aguiar; João Correia Lopes

    2011-01-01

    Most existing location-based services rely on ubiquitous connectivity to deliver location-based contents to the users. However, connectivity is not available anywhere at anytime even in urban centres. Underground, indoors, remote areas, and foreign countries are examples situations where users commonly do not have guaranteed connectivity but could profit from location-based contents. In this work, we propose an open platform for publishing, distributing and maintaining location-based contents...

  17. ‘"Education-based Research"

    Degn Johansson, Troels

    This paper lays out a concept of education-based research-the production of research knowledge within the framework of tertiary design education-as an integration of problem-based learning and research-based education. This leads to a critique of reflective practice as the primary way to facilitate...... learning at this level, a discussion of the nature of design problems in the instrumentalist tradition, and some suggestions as to how design studies curricula may facilitate education-based research....

  18. Health Physics Positions Data Base

    Kerr, G.D.; Borges, T.; Stafford, R.S.; Lu, P.Y.; Carter, D.

    1992-05-01

    The Health Physics Positions (HPPOS) Data Base of the Nuclear Regulatory Commission (NRC) is a collection of summaries of NRC staff positions on a wide range of topics in radiation protection (health physics). The bases for the data base are 247 original documents in the form of letters, memoranda, and excerpts from technical reports. The HPPOS Data Base was developed by the NRC Headquarters and Regional Offices to help ensure uniformity in inspections, enforcement, and licensing actions

  19. Memory-Based Shallow Parsing

    Sang, Erik F. Tjong Kim

    2002-01-01

    We present memory-based learning approaches to shallow parsing and apply these to five tasks: base noun phrase identification, arbitrary base phrase recognition, clause detection, noun phrase parsing and full parsing. We use feature selection techniques and system combination methods for improving the performance of the memory-based learner. Our approach is evaluated on standard data sets and the results are compared with that of other systems. This reveals that our approach works well for ba...

  20. Lunar Base Heat Pump

    Walker, D.; Fischbach, D.; Tetreault, R.

    1996-01-01

    The objective of this project was to investigate the feasibility of constructing a heat pump suitable for use as a heat rejection device in applications such as a lunar base. In this situation, direct heat rejection through the use of radiators is not possible at a temperature suitable for lde support systems. Initial analysis of a heat pump of this type called for a temperature lift of approximately 378 deg. K, which is considerably higher than is commonly called for in HVAC and refrigeration applications where heat pumps are most often employed. Also because of the variation of the rejection temperature (from 100 to 381 deg. K), extreme flexibility in the configuration and operation of the heat pump is required. A three-stage compression cycle using a refrigerant such as CFC-11 or HCFC-123 was formulated with operation possible with one, two or three stages of compression. Also, to meet the redundancy requirements, compression was divided up over multiple compressors in each stage. A control scheme was devised that allowed these multiple compressors to be operated as required so that the heat pump could perform with variable heat loads and rejection conditions. A prototype heat pump was designed and constructed to investigate the key elements of the high-lift heat pump concept. Control software was written and implemented in the prototype to allow fully automatic operation. The heat pump was capable of operation over a wide range of rejection temperatures and cooling loads, while maintaining cooling water temperature well within the required specification of 40 deg. C +/- 1.7 deg. C. This performance was verified through testing.

  1. Performance-Based Funding Brief

    Washington Higher Education Coordinating Board, 2011

    2011-01-01

    A number of states have made progress in implementing performance-based funding (PFB) and accountability. This policy brief summarizes main features of performance-based funding systems in three states: Tennessee, Ohio, and Indiana. The brief also identifies key issues that states considering performance-based funding must address, as well as…

  2. Benefit-based tree valuation

    E.G. McPherson

    2007-01-01

    Benefit-based tree valuation provides alternative estimates of the fair and reasonable value of trees while illustrating the relative contribution of different benefit types. This study compared estimates of tree value obtained using cost- and benefit-based approaches. The cost-based approach used the Council of Landscape and Tree Appraisers trunk formula method, and...

  3. Different perspectives on economic base.

    Lisa K. Crone; Richard W. Haynes; Nicholas E. Reyna

    1999-01-01

    Two general approaches for measuring the economic base are discussed. Each method is used to define the economic base for each of the counties included in the Interior Columbia Basin Ecosystem Management Project area. A more detailed look at four selected counties results in similar findings from different approaches. Limitations of economic base analysis also are...

  4. Memory-Based Shallow Parsing

    Tjong Kim Sang, E.F.

    2002-01-01

    We present memory-based learning approaches to shallow parsing and apply these to five tasks: base noun phrase identification, arbitrary base phrase recognition, clause detection, noun phrase parsing and full parsing. We use feature selection techniques and system combination methods for improving

  5. Condition based spare parts supply

    Lin, X.; Basten, Robertus Johannes Ida; Kranenburg, A.A.; van Houtum, Geert-Jan

    2012-01-01

    We consider a spare parts stock point that serves an installed base of machines. Each machine contains the same critical component, whose degradation behavior is described by a Markov process. We consider condition based spare parts supply, and show that an optimal, condition based inventory policy

  6. Evidence-based dentistry.

    Chambers, David W

    2010-01-01

    Both panegyric and criticism of evidence-based dentistry tend to be clumsy because the concept is poorly defined. This analysis identifies several contributions to the profession that have been made under the EBD banner. Although the concept of clinicians integrating clinical epidemiology, the wisdom of their practices, and patients' values is powerful, its implementation has been distorted by a too heavy emphasis of computerized searches for research findings that meet the standards of academics. Although EBD advocates enjoy sharing anecdotal accounts of mistakes others have made, faulting others is not proof that one's own position is correct. There is no systematic, high-quality evidence that EBD is effective. The metaphor of a three-legged stool (evidence, experience, values, and integration) is used as an organizing principle. "Best evidence" has become a preoccupation among EBD enthusiasts. That overlong but thinly developed leg of the stool is critiqued from the perspectives of the criteria for evidence, the difference between internal and external validity, the relationship between evidence and decision making, the ambiguous meaning of "best," and the role of reasonable doubt. The strongest leg of the stool is clinical experience. Although bias exists in all observations (including searches for evidence), there are simple procedures that can be employed in practice to increase useful and objective evidence there, and there are dangers in delegating policy regarding allowable treatments to external groups. Patient and practitioner values are the shortest leg of the stool. As they are so little recognized, their integration in EBD is problematic and ethical tensions exist where paternalism privileges science over patient's self-determined best interests. Four potential approaches to integration are suggested, recognizing that there is virtually no literature on how the "seat" of the three-legged stool works or should work. It is likely that most dentists

  7. Barrier Data Base user's guide

    Worrell, R.B.; Gould, D.J.; Wall, D.W.

    1977-06-01

    A special purpose data base for physical security barriers has been developed. In addition to barriers, the entities accommodated by the Barrier Data Base (BDB) include threats and references. A threat is established as a configuration of people and equipment which has been employed to penetrate (or attempt to penetrate) a barrier. References are used to cite publications pertinent to the barriers and threats in the data base. Utilization and maintenance of the Barrier Data Base is achieved with LIST, QUERY, ENTER, DELETE, and CHANGE commands which are used to manipulate the data base entities

  8. From oil-based mud to water-based mud

    Christiansen, C.

    1991-01-01

    Maersk Olie og Gas AS has used low toxic oil-based muds extensively since 1982 for drilling development wells and later in the development of horizontal well drilling techniques. However, in view of the strong drive towards a reduction in the amount of oil discharged to the North Sea from the oil industry, Maersk Olie og Gas AS initiated trials with new or improved types of water-based mud, first in deviated wells (1989) and then in horizontal wells (1990). The paper reviews Maersk Olie og Gas As experience with oil-based mud since the drilling of the first horizontal well in 1987, specifically with respect to cuttings washing equipment, oil retention on cuttings, and the procedure for monitoring of this parameter. It describes the circumstances leading to the decision to revert to water-based mud systems. Finally, it reviews the experience gained so far with the new improved types of water-based mud systems, mainly glycol and KCl/polymer mud systems. Comparison of operational data, such as rate of penetration, torque and drag, etc., is made between wells drilled with oil-based mud and water-based mud. The trials with the new improved types of water-based mud systems have been positive, i.e. horizontal wells can be drilled successfully with water-based mud. As a result, Maersk Olie og and Gas AS has decided to discontinue the use of low toxic oil-based muds in the Danish sector of the North Sea

  9. Workplace Based Assessment in Psychiatry

    Ayse Devrim Basterzi

    2009-11-01

    Full Text Available Workplace based assessment refers to the assessment of working practices based on what doctors actually do in the workplace, and is predominantly carried out in the workplace itself. Assessment drives learning and it is therefore essential that workplace-based assessment focuses on important attributes rather than what is easiest to assess. Workplacebased assessment is usually competency based. Workplace based assesments may well facilitate and enhance various aspects of educational supervisions, including its structure, frequency and duration etc. The structure and content of workplace based assesments should be monitored to ensure that its benefits are maximised by remaining tailored to individual trainees' needs. Workplace based assesment should be used for formative and summative assessments. Several formative assessment methods have been developed for use in the workplace such as mini clinical evaluation exercise (mini-cex, evidence based journal club assesment and case based discussion, multi source feedback etc. This review discusses the need of workplace based assesments in psychiatry graduate education and introduces some of the work place based assesment methods.

  10. Case-based reasoning: The marriage of knowledge base and data base

    Pulaski, Kirt; Casadaban, Cyprian

    1988-01-01

    The coupling of data and knowledge has a synergistic effect when building an intelligent data base. The goal is to integrate the data and knowledge almost to the point of indistinguishability, permitting them to be used interchangeably. Examples given in this paper suggest that Case-Based Reasoning is a more integrated way to link data and knowledge than pure rule-based reasoning.

  11. Knowledge base verification based on enhanced colored petri net

    Kim, Jong Hyun; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    Verification is a process aimed at demonstrating whether a system meets it`s specified requirements. As expert systems are used in various applications, the knowledge base verification of systems takes an important position. The conventional Petri net approach that has been studied recently in order to verify the knowledge base is found that it is inadequate to verify the knowledge base of large and complex system, such as alarm processing system of nuclear power plant. Thus, we propose an improved method that models the knowledge base as enhanced colored Petri net. In this study, we analyze the reachability and the error characteristics of the knowledge base and apply the method to verification of simple knowledge base. 8 refs., 4 figs. (Author)

  12. Knowledge base verification based on enhanced colored petri net

    Kim, Jong Hyun; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    Verification is a process aimed at demonstrating whether a system meets it`s specified requirements. As expert systems are used in various applications, the knowledge base verification of systems takes an important position. The conventional Petri net approach that has been studied recently in order to verify the knowledge base is found that it is inadequate to verify the knowledge base of large and complex system, such as alarm processing system of nuclear power plant. Thus, we propose an improved method that models the knowledge base as enhanced colored Petri net. In this study, we analyze the reachability and the error characteristics of the knowledge base and apply the method to verification of simple knowledge base. 8 refs., 4 figs. (Author)

  13. XML-Based SHINE Knowledge Base Interchange Language

    James, Mark; Mackey, Ryan; Tikidjian, Raffi

    2008-01-01

    The SHINE Knowledge Base Interchange Language software has been designed to more efficiently send new knowledge bases to spacecraft that have been embedded with the Spacecraft Health Inference Engine (SHINE) tool. The intention of the behavioral model is to capture most of the information generally associated with a spacecraft functional model, while specifically addressing the needs of execution within SHINE and Livingstone. As such, it has some constructs that are based on one or the other.

  14. Managing the Gap between Curriculum Based and Problem Based Learning

    Bygholm, Ann; Buus, Lillian

    2009-01-01

    /or but rather both/and. In this paper we describe an approach to design and delivery of online courses in computer science which on the one hand is based on a specified curriculum and on the other hand gives room for different learning strategies, problem based learning being one of them. We discuss......Traditionally there has been a clear distinction between curriculum based and problem based approaches to accomplish learning. Preferred approaches depend of course on conviction, culture, traditions and also on the specific learning situation. We will argue that it is not a question of either...

  15. Acids and bases solvent effects on acid-base strenght

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  16. Computer-based and web-based radiation safety training

    Owen, C., LLNL

    1998-03-01

    The traditional approach to delivering radiation safety training has been to provide a stand-up lecture of the topic, with the possible aid of video, and to repeat the same material periodically. New approaches to meeting training requirements are needed to address the advent of flexible work hours and telecommuting, and to better accommodate individuals learning at their own pace. Computer- based and web-based radiation safety training can provide this alternative. Computer-based and web- based training is an interactive form of learning that the student controls, resulting in enhanced and focused learning at a time most often chosen by the student.

  17. Concurrent array-based queue

    Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2015-01-06

    According to one embodiment, a method for implementing an array-based queue in memory of a memory system that includes a controller includes configuring, in the memory, metadata of the array-based queue. The configuring comprises defining, in metadata, an array start location in the memory for the array-based queue, defining, in the metadata, an array size for the array-based queue, defining, in the metadata, a queue top for the array-based queue and defining, in the metadata, a queue bottom for the array-based queue. The method also includes the controller serving a request for an operation on the queue, the request providing the location in the memory of the metadata of the queue.

  18. The knowledge base of journalism

    Svith, Flemming

    In this paper I propose the knowledge base as a fruitful way to apprehend journalism. With the claim that the majority of practice is anchored in knowledge – understood as 9 categories of rationales, forms and levels – this knowledge base appears as a contextual look at journalists’ knowledge......, and place. As an analytical framework, the knowledge base is limited to understand the practice of newspaper journalists, but, conversely, the knowledge base encompasses more general beginnings through the inclusion of overall structural relationships in the media and journalism and general theories...... on practice and knowledge. As the result of an abductive reasoning is a theory proposal, there is a need for more deductive approaches to test the validity of this knowledge base claim. It is thus relevant to investigate which rationales are included in the knowledge base of journalism, as the dimension does...

  19. Aperiodic-metamaterial-based absorber

    Quanlong Yang

    2017-09-01

    Full Text Available The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber, how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  20. Estimating North Dakota's Economic Base

    Coon, Randal C.; Leistritz, F. Larry

    2009-01-01

    North Dakota’s economic base is comprised of those activities producing a product paid for by nonresidents, or products exported from the state. North Dakota’s economic base activities include agriculture, mining, manufacturing, tourism, and federal government payments for construction and to individuals. Development of the North Dakota economic base data is important because it provides the information to quantify the state’s economic growth, and it creates the final demand sectors for the N...

  1. Principles of models based engineering

    Dolin, R.M.; Hefele, J.

    1996-11-01

    This report describes a Models Based Engineering (MBE) philosophy and implementation strategy that has been developed at Los Alamos National Laboratory`s Center for Advanced Engineering Technology. A major theme in this discussion is that models based engineering is an information management technology enabling the development of information driven engineering. Unlike other information management technologies, models based engineering encompasses the breadth of engineering information, from design intent through product definition to consumer application.

  2. Logically automorphically equivalent knowledge bases

    Aladova, Elena; Plotkin, Tatjana

    2017-01-01

    Knowledge bases theory provide an important example of the field where applications of universal algebra and algebraic logic look very natural, and their interaction with practical problems arising in computer science might be very productive. In this paper we study the equivalence problem for knowledge bases. Our interest is to find out how the informational equivalence is related to the logical description of knowledge. Studying various equivalences of knowledge bases allows us to compare d...

  3. Brain-Based Learning and Standards-Based Elementary Science.

    Konecki, Loretta R.; Schiller, Ellen

    This paper explains how brain-based learning has become an area of interest to elementary school science teachers, focusing on the possible relationships between, and implications of, research on brain-based learning to the teaching of science education standards. After describing research on the brain, the paper looks at three implications from…

  4. Fatigue data bases in Europe

    Olivier, R.; Koettgen, V.B.; Seeger, T.; Boller, C.

    1988-01-01

    Based on an inquiry with well-known European fatigue institutions the paper describes existing more or less extensive collections and data bases of S-N and crack growth data, mainly on unwelded and welded steel and aluminium in organizations and countries as follows: CEC, ESA, Federal Republic of Germany, GDR, Italy, Norway, Republic of Ireland, Switzerland, UK. This documentation of the present state is completed by a short survey on available European fatigue standards and design rules, serving as a data base for nominal materials data. Requirements for data base concepts, contents, user interface and data structure are presented in a short overview. (orig./HP)

  5. Capability-based computer systems

    Levy, Henry M

    2014-01-01

    Capability-Based Computer Systems focuses on computer programs and their capabilities. The text first elaborates capability- and object-based system concepts, including capability-based systems, object-based approach, and summary. The book then describes early descriptor architectures and explains the Burroughs B5000, Rice University Computer, and Basic Language Machine. The text also focuses on early capability architectures. Dennis and Van Horn's Supervisor; CAL-TSS System; MIT PDP-1 Timesharing System; and Chicago Magic Number Machine are discussed. The book then describes Plessey System 25

  6. New Mexico Geothermal Data Base

    Witcher, J.C.; Whittier, J.; Morgan, R.

    1990-01-01

    This paper reports on the New Mexico Geothermal Data Base (NMGDB) which is a comprehensive public-domain data base of low-temperature geothermal resource information for New Mexico that is designed to assist researchers and developers. A broad range of geoscience, engineering, climatic, economic, and land status information are complied in the dBASE III PLUS data base management system for use on an IBM or IBM-compatible personal computer. A user friendly menu format with on-screen prompts allows easy and convenient use

  7. Isochronous cyclotron data base description

    Kiyan, I.N.; Vorozhtsov, S.B.; Tarashkevich, R.

    2004-01-01

    The relational data base of the control parameters of the isochronous cyclotron, Isochronous Cyclotron Data Base (ICDB), is described. The relational data base under consideration, written in Transact SQL for the MS SQL Server 2000 with the use of MS Enterprise Manager and MS Query Analyzer, was installed on the server of the AIC144 isochronous cyclotron in Krakow, which operates under the control of the operating system MS Windows Server 2003 (Standard Edition). The interface of the data base under considerations is written in C++ with the use of Visual C++ .NET and is built in the Cyclotron Operator Help Program (COHP), which is used for modeling the operational modes of the isochronous cyclotron. Communication between the COHP and the relational data base is realised on the base of the Open Data Base Connectivity protocol. The relational data base of the control parameter of the isochronous cyclotron is intended: firstly, for systematization and automatic use of all measured and modelled magnetic field maps in the process of modeling the operational modes; secondly, for systematization and convenient access to the stored operational modes; thirdly, for simplifying the operator's work. The relational data base of the control parameter of the isochronous cyclotron reflects its physical structure and the logic of its operator's work. (author)

  8. Theory-Based Stakeholder Evaluation

    Hansen, Morten Balle; Vedung, Evert

    2010-01-01

    This article introduces a new approach to program theory evaluation called theory-based stakeholder evaluation or the TSE model for short. Most theory-based approaches are program theory driven and some are stakeholder oriented as well. Practically, all of the latter fuse the program perceptions of the various stakeholder groups into one unitary…

  9. Package-based software development

    Jonge, de M.; Chroust, G.; Hofer, C.

    2003-01-01

    The main goal of component-based software engineering is to decrease development time and development costs of software systems, by reusing prefabricated building blocks. Here we focus on software reuse within the implementation of such component-based applications, and on the corresponding software

  10. Cloud-Based Data Storage

    Waters, John K.

    2011-01-01

    The vulnerability and inefficiency of backing up data on-site is prompting school districts to switch to more secure, less troublesome cloud-based options. District auditors are pushing for a better way to back up their data than the on-site, tape-based system that had been used for years. About three years ago, Hendrick School District in…

  11. Cluster Based Vector Attribute Filtering

    Kiwanuka, Fred N.; Wilkinson, Michael H.F.

    2016-01-01

    Morphological attribute filters operate on images based on properties or attributes of connected components. Until recently, attribute filtering was based on a single global threshold on a scalar property to remove or retain objects. A single threshold struggles in case no single property or

  12. Dog Mathematics: Exploring Base-4

    Kurz, Terri L.; Yanik, H. Bahadir; Lee, Mi Yeon

    2016-01-01

    Using a dog's paw as a basis for numerical representation, sixth grade students explored how to count and regroup using the dog's four digital pads. Teachers can connect these base-4 explorations to the conceptual meaning of place value and regrouping using base-10.

  13. Forest biomass-based energy

    Janaki R. R. Alavalapati; Pankaj Lal; Andres Susaeta; Robert C. Abt; David N. Wear

    2013-01-01

    Key FindingsHarvesting woody biomass for use as bioenergy is projected to range from 170 million to 336 million green tons by 2050, an increase of 54 to 113 percent over current levels.Consumption projections for forest biomass-based energy, which are based on Energy Information Administration projections, have a high level of...

  14. Generic component failure data base

    Eide, S.A.; Calley, M.B.

    1992-01-01

    This report discusses comprehensive component generic failure data base which has been developed for light water reactor probabilistic risk assessments. The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) was used to generate component failure rates. Using this approach, most of the failure rates are based on actual plant data rather then existing estimates

  15. Groebner bases in perturbative calculations

    Gerdt, Vladimir P. [Laboratory of Information Technologies, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2004-10-01

    In this paper we outline the most general and universal algorithmic approach to reduction of loop integrals to basic integrals. The approach is based on computation of Groebner bases for recurrence relations derived from the integration by parts method. In doing so we consider generic recurrence relations when propagators have arbitrary integer powers treated as symbolic variables (indices) for the relations.

  16. Groebner bases in perturbative calculations

    Gerdt, Vladimir P.

    2004-01-01

    In this paper we outline the most general and universal algorithmic approach to reduction of loop integrals to basic integrals. The approach is based on computation of Groebner bases for recurrence relations derived from the integration by parts method. In doing so we consider generic recurrence relations when propagators have arbitrary integer powers treated as symbolic variables (indices) for the relations

  17. Ground-based photo monitoring

    Frederick C. Hall

    2000-01-01

    Ground-based photo monitoring is repeat photography using ground-based cameras to document change in vegetation or soil. Assume those installing the photo location will not be the ones re-photographing it. This requires a protocol that includes: (1) a map to locate the monitoring area, (2) another map diagramming the photographic layout, (3) type and make of film such...

  18. Methods in Logic Based Control

    Christensen, Georg Kronborg

    1999-01-01

    Desing and theory of Logic Based Control systems.Boolean Algebra, Karnaugh Map, Quine McClusky's algorithm. Sequential control design. Logic Based Control Method, Cascade Control Method. Implementation techniques: relay, pneumatic, TTL/CMOS,PAL and PLC- and Soft_PLC implementation. PLC...

  19. Models for Rational Number Bases

    Pedersen, Jean J.; Armbruster, Frank O.

    1975-01-01

    This article extends number bases to negative integers, then to positive rationals and finally to negative rationals. Methods and rules for operations in positive and negative rational bases greater than one or less than negative one are summarized in tables. Sample problems are explained and illustrated. (KM)

  20. Defining Nature-Based Preschools

    Larimore, Rachel

    2016-01-01

    Nature-based early childhood education. Nature-based preschool. Nature preschool. Forest kindergarten. Nature kindergarten. Waldkindergarten. Forest school. These are a few of the program terms currently being discussed among early childhood environmental education professionals in the United States. Why is there so much discussion about the names…

  1. Plasma-based accelerator structures

    Schroeder, Carl B.

    1999-01-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas

  2. Machine intelligence and knowledge bases

    Furukawa, K

    1981-09-01

    The basic functions necessary in machine intelligence are a knowledge base and a logic programming language such as PROLOG using deductive reasoning. Recently inductive reasoning based on meta knowledge and default reasoning have been developed. The creative thought model of Lenit is reviewed and the concept of knowledge engineering is introduced. 17 references.

  3. Automated deficiency letter data base

    Jones, R.D.

    1983-12-01

    An automated data base relevant to the various licensee deficiencies that accrue during the materials licensing application review process of the Nuclear Regulatory Commission (NRC) is described. A data base management system (DBMs) is used for data retrieval, file-tending, and examination of the interrelationships among the data types in the data base. Use of word processors to emulate computer terminals for the purpose of data base population (loading) and report generation is discussed. Also described is the technique used to link, for update purposes, the data base (accessed by means of SYSTEM 2000 on a CDC 6600 computer) to the NRC Material License Master File resident on the National Institutes of Health (NIH) IBM System 370 computer. A user's manual that provides easy-to-understand instructions for the nonprogramming user on how to generate ad hoc analytical reports to facilitate management decisions is also included

  4. Power Reactor Embrittlement Data Base

    Kam, F.B.K.; Stallmann, F.W.; Wang, J.A.

    1990-01-01

    Regulatory and research evaluations of embrittlement predication models and of pressure vessel integrity can be greatly expedited by the use of a well-designed, computerized data base. The Power Reactor Embrittlement Data Base (PR-EDB) is such a comprehensive collection of data for US commercial nuclear reactors. The Nuclear Regulatory Commission (NRC) has provided financial support, and the Electric Power Research Institute (EPRI) has provided technical assistance in the quality assurance (QA) of the data to establish an industry-wide data base that will be maintained and updated on a long-term basis. Successful applications of the data base to several of NRC's evaluations have received favorable response and support for its continuation. The future direction of the data base has been designed to include the test reactor and other types of data of interest to the regulators and the researchers. 1 ref

  5. Team-based global organizations

    Zander, Lena; Butler, Christina; Mockaitis, Audra

    2015-01-01

    diversity in enhancing team creativity and performance, and 2) the sharing of knowledge in team-based organizations, while the other two themes address global team leadership: 3) the unprecedented significance of social capital for the success of global team leader roles; and 4) the link between shared......This chapter draws on a panel discussion of the future of global organizing as a team-based organization at EIBA 2014 in Uppsala, Sweden. We began by discussing contemporary developments of hybrid forms of hierarchy and teams-based organizing, but we venture to propose that as organizations become...... characterized by decreased importance of hierarchal structures, more fluidity across borders, even a possible dissolution of firm boundaries, we move towards team-based organizing as an alternative to more traditional forms of hierarchical-based organizing in global firms. To provide input for a discussion...

  6. Content-based intermedia synchronization

    Oh, Dong-Young; Sampath-Kumar, Srihari; Rangan, P. Venkat

    1995-03-01

    Inter-media synchronization methods developed until now have been based on syntactic timestamping of video frames and audio samples. These methods are not fully appropriate for the synchronization of multimedia objects which may have to be accessed individually by their contents, e.g. content-base data retrieval. We propose a content-based multimedia synchronization scheme in which a media stream is viewed as hierarchial composition of smaller objects which are logically structured based on the contents, and the synchronization is achieved by deriving temporal relations among logical units of media object. content-based synchronization offers several advantages such as, elimination of the need for time stamping, freedom from limitations of jitter, synchronization of independently captured media objects in video editing, and compensation for inherent asynchronies in capture times of video and audio.

  7. Content-Based Image Retrial Based on Hadoop

    DongSheng Yin

    2013-01-01

    Full Text Available Generally, time complexity of algorithms for content-based image retrial is extremely high. In order to retrieve images on large-scale databases efficiently, a new way for retrieving based on Hadoop distributed framework is proposed. Firstly, a database of images features is built by using Speeded Up Robust Features algorithm and Locality-Sensitive Hashing and then perform the search on Hadoop platform in a parallel way specially designed. Considerable experimental results show that it is able to retrieve images based on content on large-scale cluster and image sets effectively.

  8. Image based Monument Recognition using Graph based Visual Saliency

    Kalliatakis, Grigorios; Triantafyllidis, Georgios

    2013-01-01

    This article presents an image-based application aiming at simple image classification of well-known monuments in the area of Heraklion, Crete, Greece. This classification takes place by utilizing Graph Based Visual Saliency (GBVS) and employing Scale Invariant Feature Transform (SIFT) or Speeded......, the images have been previously processed according to the Graph Based Visual Saliency model in order to keep either SIFT or SURF features corresponding to the actual monuments while the background “noise” is minimized. The application is then able to classify these images, helping the user to better...

  9. radio frequency based radio frequency based water level monitor

    eobe

    ABSTRACT. This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor and .... range the wireless can cover but in this prototype, it ... power supply to the system, the sensed water level is.

  10. Value-based metrics and Internet-based enterprises

    Gupta, Krishan M.

    2001-10-01

    Within the last few years, a host of value-based metrics like EVA, MVA, TBR, CFORI, and TSR have evolved. This paper attempts to analyze the validity and applicability of EVA and Balanced Scorecard for Internet based organizations. Despite the collapse of the dot-com model, the firms engaged in e- commerce continue to struggle to find new ways to account for customer-base, technology, employees, knowledge, etc, as part of the value of the firm. While some metrics, like the Balance Scorecard are geared towards internal use, others like EVA are for external use. Value-based metrics are used for performing internal audits as well as comparing firms against one another; and can also be effectively utilized by individuals outside the firm looking to determine if the firm is creating value for its stakeholders.

  11. SB certification for mixture-based specification for flexible base.

    2012-10-01

    Presentation topics: : Establish List of Qualified Producers; : Producers Responsible for Process Control/Quality Control; : Reduce TxDOT Sampling and Testing; : Expedite Aggregate Base Acceptance; : Share Responsibility (Producer/TxDOT) for Quality ...

  12. Object-Based Benefits without Object-Based Representations

    Alvarez, George Angelo; Fougnie, Daryl; Cormiea, Sarah M

    2012-01-01

    The organization of visual information into objects strongly influences visual memory: Displays with objects defined by two features (e.g. color, orientation) are easier to remember than displays with twice as many objects defined by one feature (Olson & Jiang, 2002). Existing theories suggest that this ‘object-benefit’ is based on object-based limitations in working memory: because a limited number of objects can be stored, packaging features together so that fewer objects have to be remembe...

  13. Designing H-shaped micromechanical filters

    Arhaug, O P; Soeraasen, O

    2006-01-01

    This paper investigates the design constraints and possibilities given when designing a micromechanical band pass filter for intermediate frequencies (e.g. 10 MHz). The class of filters are based on coupled clamped-clamped beams constituting an H-shaped structure. A primary beam can electrostatically be activated in one of its different harmonic modes, setting the filter center frequency. The motion is transferred to an accompanying beam of equal dimensions by a mechanical coupling beam. The placement or coupling points of the quarterwavelength coupling beam which connects the vertically resonating beams is critical with respect to the bandwidth of the filters. Of special concern has been to investigate realistic dimensions allowing the filters to be processed by an actual foundry process and to find out how the choice of materials and actual dimensions would affect the performance

  14. Designing Android Based Augmented Reality Location-Based Service Application

    Alim Hardiansyah

    2018-01-01

    Full Text Available Android is an operating system for Linux based smartphone. Android provides an open platform for the developers to create their own application. The most developed and used application now is location based application. This application gives personalization service for mobile device user and is customized to their location. Location based service also gives an opportunity for the developers to develop and increase the value of service. One of the technologies that could be combined with location based application is augmented reality. Augmented reality combines the virtual world with the real one. By the assistance of augmented reality, our surrounding environment could interact in digital form. Information of objects and environment surround us could be added to the augmented reality system and presented. Based on the background, the writers tried to implement those technologies on now rapidly developing android application as a final project to achieve bachelor degree in Department of Informatics Engineering, Faculty of Information Technology and Visual Communication, Al Kamal Science and Technology Institute. This application could be functioned to locate school by using location based service technology with the assistance of navigational applications such as waze and google maps, in form of live direction process through the smartphone

  15. WPS criterion proposition based on experimental data base interpretation

    Chapuliot, S.; Izard, J.P.; Moinereau, D.; Marie, S.

    2011-01-01

    This article gives the background and the methodology developed to define a K J based criterion for brittle fracture of Reactor Pressure Vessel (RPV) submitted to Pressurized Thermal Shock (PTS), and taking into account Warm Pre Stressing effect (WPS). The first step of this methodology is the constitution of an experimental data base. This work was performed through bibliography and partnerships, and allows merging experimental results dealing with: -) Various ferritic steels; -) Various material states (as received, thermally aged, irradiated...); -) Various mode of fracture (cleavage, inter-granular, mixed mode); -) Various specimen geometry and size (CT, SENB, mock-ups); -) Various thermo-mechanical transients. Based on this experimental data base, a simple K J based limit is proposed and compared to experimental results. Parametric studies are performed in order to define the main parameters of the problem. Finally, a simple proposition based on a detailed analysis of tests results is performed. This proposition giving satisfactory results in every cases, it constitutes a good candidate for integration in French RSE-M code for in service assessment. (authors)

  16. EPICS Application Based on RTEMS

    Shi Haoli; Wang Chunhong; Tang Jingyu

    2009-01-01

    At present, in the accelerator field all over the world, the control system is established with EPICS, which is a configuration software package based on Ethernet and distributed control system. Early version of EPICS was developed based on VxWorks. Now, EPICS international collaboration group is dedicating to supporting open source, free RTEMS, and extending RTEMS into the newer version of EPICS3.14. The paper illustrates the development, characteristic of RTEMS, compares the performances of several ordinary RTOS, builds RTEMS operating system based on MVME5500, and finally presents an EPICS application example on RTEMS. (authors)

  17. Querying Natural Logic Knowledge Bases

    Andreasen, Troels; Bulskov, Henrik; Jensen, Per Anker

    2017-01-01

    This paper describes the principles of a system applying natural logic as a knowledge base language. Natural logics are regimented fragments of natural language employing high level inference rules. We advocate the use of natural logic for knowledge bases dealing with querying of classes...... in ontologies and class-relationships such as are common in life-science descriptions. The paper adopts a version of natural logic with recursive restrictive clauses such as relative clauses and adnominal prepositional phrases. It includes passive as well as active voice sentences. We outline a prototype...... for partial translation of natural language into natural logic, featuring further querying and conceptual path finding in natural logic knowledge bases....

  18. Home-based Healthcare Technology

    Verdezoto, Nervo

    of these systems target a specific treatment or condition and might not be sufficient to support the care management work at home. Based on a case study approach, my research investigates home-based healthcare practices and how they can inform future design of home-based healthcare technology that better account......Sustaining daily, unsupervised healthcare activities in non-clinical settings such as the private home can challenge, among others, older adults. To support such unsupervised care activities, an increasingly number of reminders and monitoring systems are being designed. However, most...

  19. Solar based hydrogen production systems

    Dincer, Ibrahim

    2013-01-01

    This book provides a comprehensive analysis of various solar based hydrogen production systems. The book covers first-law (energy based) and second-law (exergy based) efficiencies and provides a comprehensive understanding of their implications. It will help minimize the widespread misuse of efficiencies among students and researchers in energy field by using an intuitive and unified approach for defining efficiencies. The book gives a clear understanding of the sustainability and environmental impact analysis of the above systems. The book will be particularly useful for a clear understanding

  20. Risk-based safety indicators

    Sedlak, J.

    2001-12-01

    The report is structured as follows: 1. Risk-based safety indicators: Typology of risk-based indicators (RBIs); Tools for defining RBIs; Requirements for the PSA model; Data sources for RBIs; Types of risks monitored; RBIs and operational safety indicators; Feedback from operating experience; PSO model modification for RBIs; RBI categorization; RBI assessment; RBI applications; Suitable RBI applications. 2. Proposal for risk-based indicators: Acquiring information from operational experience; Method of acquiring safety relevance coefficients for the systems from a PSA model; Indicator definitions; On-line indicators. 3. Annex: Application of RBIs worldwide. (P.A.)

  1. Reconsidering Community-based Retailing

    Maughan, Rebecca; O'Driscoll, Aidan

    2012-01-01

    One of the areas with great potential for economic, social and environmental benefit is community-based retailing. The concept of community based retailing can incorporate a number of different tenets. We suggest that it is retailing that is based close to the community it serves, usually within the town or village centre rather than out-of-town locations, and which is composed of a diverse range of small and medium sized business that are often independently or co-operatively owned. These co...

  2. FEMA DFIRM Base Flood Elevations

    Minnesota Department of Natural Resources — The Base Flood Elevation (BFE) table is required for any digital data where BFE lines will be shown on the corresponding Flood Insurance Rate Map (FIRM). Normally,...

  3. Oil-based paint poisoning

    Paint - oil-based - poisoning ... Hydrocarbons are the primary poisonous ingredient in oil paints. Some oil paints have heavy metals such as lead, mercury, cobalt, and barium added as pigment. These heavy metals can cause additional ...

  4. Imprinted silicon-based nanophotonics

    Borel, Peter Ingo; Olsen, Brian Bilenberg; Frandsen, Lars Hagedorn

    2007-01-01

    We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern ...

  5. Generalized eigenvalue based spectrum sensing

    Shakir, Muhammad; Alouini, Mohamed-Slim

    2012-01-01

    of the decision threshold of the respective detectors. The decision threshold has been calculated in a closed form which is based on the approximation of Cumulative Distribution Functions (CDFs) of the respective test statistics. In this context, we exchange

  6. Reliability-Based Code Calibration

    Faber, M.H.; Sørensen, John Dalsgaard

    2003-01-01

    The present paper addresses fundamental concepts of reliability based code calibration. First basic principles of structural reliability theory are introduced and it is shown how the results of FORM based reliability analysis may be related to partial safety factors and characteristic values....... Thereafter the code calibration problem is presented in its principal decision theoretical form and it is discussed how acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for ultimate...... and serviceability limit states. Finally the paper describes the Joint Committee on Structural Safety (JCSS) recommended procedure - CodeCal - for the practical implementation of reliability based code calibration of LRFD based design codes....

  7. Cage-based performance capture

    Savoye, Yann

    2014-01-01

    Nowadays, highly-detailed animations of live-actor performances are increasingly easier to acquire and 3D Video has reached considerable attentions in visual media production. In this book, we address the problem of extracting or acquiring and then reusing non-rigid parametrization for video-based animations. At first sight, a crucial challenge is to reproduce plausible boneless deformations while preserving global and local captured properties of dynamic surfaces with a limited number of controllable, flexible and reusable parameters. To solve this challenge, we directly rely on a skin-detached dimension reduction thanks to the well-known cage-based paradigm. First, we achieve Scalable Inverse Cage-based Modeling by transposing the inverse kinematics paradigm on surfaces. Thus, we introduce a cage inversion process with user-specified screen-space constraints. Secondly, we convert non-rigid animated surfaces into a sequence of optimal cage parameters via Cage-based Animation Conversion. Building upon this re...

  8. Physical bases of nuclear medicine

    Isabelle, D.B.; Ducassou, D.

    1975-01-01

    The physical bases of nuclear medicine are outlined in several chapters devoted successively to: atomic and nuclear structures; nuclear reactions; radioactiity laws; a study of different types of disintegration; the interactions of radiations with matter [fr

  9. GCCS Spatial Data Base Module

    Bell, Paul

    1998-01-01

    .... JMTK is divided into three primary areas: (1) Visual, (2) Analysis (non-visual), and (3) Spatial Data Base (SDBM). The primary objective of the SDBM effort is to define, design, develop and test mapping, charting and geodesy...

  10. Surface stress-based biosensors.

    Sang, Shengbo; Zhao, Yuan; Zhang, Wendong; Li, Pengwei; Hu, Jie; Li, Gang

    2014-01-15

    Surface stress-based biosensors, as one kind of label-free biosensors, have attracted lots of attention in the process of information gathering and measurement for the biological, chemical and medical application with the development of technology and society. This kind of biosensors offers many advantages such as short response time (less than milliseconds) and a typical sensitivity at nanogram, picoliter, femtojoule and attomolar level. Furthermore, it simplifies sample preparation and testing procedures. In this work, progress made towards the use of surface stress-based biosensors for achieving better performance is critically reviewed, including our recent achievement, the optimally circular membrane-based biosensors and biosensor array. The further scientific and technological challenges in this field are also summarized. Critical remark and future steps towards the ultimate surface stress-based biosensors are addressed. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Industry Based Survey (IBS) Yellowtail

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Southern New England Yellowtail Flounder Industry-Based Survey" was a collaboration between the Rhode Island Division of Fish and Wildlife and the fishing...

  12. Industry Based Survey (IBS) Cod

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Gulf of Maine Atlantic Cod Industry-Based Survey" was a collaboration of the Massachusetts Division of Marine Fisheries and the fishing industry, with support...

  13. US Air Force Base Observations

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly observations taken by U.S. Air Force personnel at bases in the United States and around the world. Foreign observations concentrated in the Middle East and...

  14. Studying Sensing-Based Systems

    Kjærgaard, Mikkel Baun

    2013-01-01

    Recent sensing-based systems involve a multitude of users, devices, and places. These types of systems challenge existing approaches for conducting valid system evaluations. Here, the author discusses such evaluation challenges and revisits existing system evaluation methodologies....

  15. Structure-Based Turbulence Model

    Reynolds, W

    2000-01-01

    .... Maire carried out this work as part of his Phi) research. During the award period we began to explore ways to simplify the structure-based modeling so that it could be used in repetitive engineering calculations...

  16. SAT-Based Software Certification

    Chaki, Sagar

    2006-01-01

    ... predicate abstraction and validated by generating and proving verification conditions. In addition, the first part of the report proposes the use of theorem provers based on Boolean propositional satisfiability (SAT...

  17. Consent Based Verification System (CBSV)

    Social Security Administration — CBSV is a fee-based service offered by SSA's Business Services Online (BSO). It is used by private companies to verify the SSNs of their customers and clients that...

  18. NORTHWOODS Wildlife Habitat Data Base

    Mark D. Nelson; Janine M. Benyus; Richard R. Buech

    1992-01-01

    Wildlife habitat data from seven Great Lakes National Forests were combined into a wildlife-habitat matrix named NORTHWOODS. Several electronic file formats of NORTHWOODS data base and documentation are available on floppy disks for microcomputers.

  19. Forming lead-based anodes

    Ogorodnichuk, V I; Voitsekhovich, R I

    1972-01-01

    Lead-based anodes can be produced by forming a layer of lead dioxide by chemical treatment in a solution of sulfuric acid in potassium permanganate at 80 to 100/sup 0/. The solution is mixed by compressed air. (RWR)

  20. Base Flood Elevation (BFE) Lines

    Department of Homeland Security — The Base Flood Elevation (BFE) table is required for any digital data where BFE lines will be shown on the corresponding Flood Insurance Rate Map (FIRM). Normally if...

  1. Hospital Value-Based Purchasing

    U.S. Department of Health & Human Services — Hospital Value-Based Purchasing (VBP) is part of the Centers for Medicare and Medicaid Services (CMS) long-standing effort to link Medicares payment system to a...

  2. Chip-based droplet sorting

    Beer, Neil Reginald; Lee, Abraham; Hatch, Andrew

    2017-11-21

    A non-contact system for sorting monodisperse water-in-oil emulsion droplets in a microfluidic device based on the droplet's contents and their interaction with an applied electromagnetic field or by identification and sorting.

  3. Consumption-based Equity Valuation

    Bach, Christian; Christensen, Peter O.

    2016-01-01

    implementations of standard valuation models, both in terms of median absolute valuation errors (MAVE) and in terms of excess returns on simple investment strategies based on the differences between model and market prices. The CCAPM-based valuation model yields a significantly lower MAVE than the best performing...... standard valuation model. Both types of models can identify investment strategies with subsequent excess returns. The CCAPM-based valuation model yields time-series of realized hedge returns with more and higher positive returns and fewer and less negative returns compared with the time-series of realized...... through a risk-adjusted cost of equity in the denominator. The risk adjustments are derived based on assumptions about the time-series properties of residual income returns and aggregate consumption rather than on historical stock returns. We compare the performance of the model with several...

  4. Consumption-based Equity Valuation

    Bach, Christian; Christensen, Peter Ove

    2013-01-01

    the performance of the model with several implementations of standard valuation models, both in terms of absolute valuation errors, and in terms of the returns on simple investment strategies based on the differences between model and market prices in the respective valuation models. The CCAPM-based valuation...... model performs substantially better than the best performing standard valuation model when comparing absolute valuation errors. Both types of models are able to identify investment strategies with subsequent excess returns but also in this setting, the CCAPM-based valuation model outperforms...... residual income for risk in the numerator rather than through a risk-adjusted cost of equity in the denominator. The risk-adjustments are derived based on assumptions about the time-series properties of residual income returns and aggregate consumption rather than on historical stock returns. We compare...

  5. Microprocessor based techniques at CESR

    Giannini, G.; Cornell Univ., Ithaca, NY

    1981-01-01

    Microprocessor based systems succesfully used in connection with the High Energy Physics experimental program at the Cornell Electron Storage Ring are described. The multiprocessor calibration system for the CUSB calorimeter is analyzed in view of present and future applications. (orig.)

  6. PHYSIOLOGY OF ACID BASE BALANCE

    Awati

    2014-12-01

    Full Text Available Acid-base, electrolyte, and metabolic disturbances are common in the intensive care unit. Almost all critically ill patients often suffer from compound acid-base and electrolyte disorders. Successful evaluation and management of such patients requires recognition of common patterns (e.g., metabolic acidosis and the ability to dissect one disorder from another. The intensivists needs to identify and correct these condition with the easiest available tools as they are the associated with multiorgan failure. Understanding the elements of normal physiology in these areas is very important so as to diagnose the pathological condition and take adequate measures as early as possible. Arterial blood gas analysis is one such tool for early detection of acid base disorder. Physiology of acid base is complex and here is the attempt to simplify it in our day to day application for the benefit of critically ill patients.

  7. Eye-based head gestures

    Mardanbegi, Diako; Witzner Hansen, Dan; Pederson, Thomas

    2012-01-01

    A novel method for video-based head gesture recognition using eye information by an eye tracker has been proposed. The method uses a combination of gaze and eye movement to infer head gestures. Compared to other gesture-based methods a major advantage of the method is that the user keeps the gaze...... mobile phone screens. The user study shows that the method detects a set of defined gestures reliably.......A novel method for video-based head gesture recognition using eye information by an eye tracker has been proposed. The method uses a combination of gaze and eye movement to infer head gestures. Compared to other gesture-based methods a major advantage of the method is that the user keeps the gaze...

  8. Base compaction specification feasibility analysis.

    2012-12-01

    The objective of this research is to establish the technical engineering and cost : analysis concepts that will enable WisDOT management to objectively evaluate the : feasibility of switching construction specification philosophies for aggregate base...

  9. Polyethylene-Based Tadpole Copolymers

    Alkayal, Nazeeha; Zhang, Zhen; Bilalis, Panayiotis; Gnanou, Yves; Hadjichristidis, Nikolaos

    2017-01-01

    Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser

  10. Knowledge-based Telecom Industry

    Vinje, Villeman; Nordkvelde, Marius

    2011-01-01

    BI Norwegian School of Management is conducting a national research project entitled “A knowledge-based Norway”. Thirteen major knowledge-based industries in Norway are being analyzed under the auspices of the project. This study assesses the underlying properties of a global knowledge hub to examine the extent to which the Norwegian telecom industry – which encompasses all telecom firms located in Norway regardless of ownership – constitutes a global knowledge hub. It commences with a ge...

  11. Power Reactor Embrittlement Data Base

    Kam, F.B.K.; Stallmann, F.W.; Wang, J.A.

    1990-01-01

    Regulatory and research evaluations of embrittlement prediction models and of vessel integrity under load can be greatly expedited by the use of a well designed, computerized embrittlement data base. The Power Reactor Embrittlement Data Base (PR-EDB) is a comprehensive collection of data from surveillance reports and other published reports of commercial nuclear reactors. The uses of the data base require that as many different data as available are collected from as many sources as possible with complete references and that subsets of relevant data can be easily retrieved and processed. The objectives of this NRC-sponsored program are the following: (1) to compile and to verify the quality of the PR-EDB; (2) to provide user-friendly software to access and process the data; (3) to explore or confirm embrittlement prediction models; and (4) to interact with standards organizations to provide the technical bases for voluntary consensus standards that can be used in regulatory guides, standard review plans, and codes. To achieve these goals, the data base architecture was designed after much discussion and planning with prospective users, namely, material scientists and members of the research staff. The current compilation of the PR-EDB (Version 1) contains results from surveillance capsule reports of 78 reactors with 381 data points for 110 different irradiated base materials and 161 data points for 79 different welds. Results from heat-affected zone materials are also listed. The time and effort required to process and evaluate different types of data in the PR-EDB have been drastically reduced from previous data bases. The Electric Power Research Institute (EPRI), reactor vendors, and utilities are in the process of providing back-up quality assurance checks of PR-EDB and will be supplementing the data base with additional data and documentation

  12. [Bases and methods of suturing].

    Vogt, P M; Altintas, M A; Radtke, C; Meyer-Marcotty, M

    2009-05-01

    If pharmaceutic modulation of scar formation does not improve the quality of the healing process over conventional healing, the surgeon must rely on personal skill and experience. Therefore a profound knowledge of wound healing based on experimental and clinical studies supplemented by postsurgical means of scar management and basic techniques of planning incisions, careful tissue handling, and thorough knowledge of suturing remain the most important ways to avoid abnormal scarring. This review summarizes the current experimental and clinical bases of surgical scar management.

  13. Chevron closing base wedge bunionectomy.

    Bruyn, J M

    1993-01-01

    The Chevron-base wedge Association for Osteosynthesis fixated bunionectomy provides a stable, aggressive correction of the severe hallux abducto valgus deformity. It is intended for the bunion requiring a double osteotomy in order to adequately reduce both intermetatarsal and proximal articular facet angle with minimal shortening and elevation. This article presents the rationale for the procedure, technique, and a 4-year follow-up of six patients with eight Chevron-base wedge bunionectomies.

  14. TFC Base de datos relacionales

    Moreno Pozuelo, Isabel

    2015-01-01

    El objetivo de este proyecto es desarrollar una base de datos relacional que contenga los datos necesarios para realizar la gestión de carteras de inversión. L'objectiu d'aquest projecte és desenvolupar una base de dades relacional que contingui les dades necessàries per realitzar la gestió de carteres d'inversió. Bachelor thesis for the Computer Science program on Databases.

  15. Instance-Based Question Answering

    2006-12-01

    cluster-based query expan- sion, learning answering strategies, machine learning in NLP To my wife Monica Abstract During recent years, question...process is typically tedious and involves expertise in crafting and implement- ing these models (e.g. rule-based), utilizing NLP resources, and...questions. For languages that use capitalization (e.g. not Chinese or Arabic ) for named entities, IBQA can make use of NE classing (e.g. “Bob Marley

  16. System Based Code: Principal Concept

    Yasuhide Asada; Masanori Tashimo; Masahiro Ueta

    2002-01-01

    This paper introduces a concept of the 'System Based Code' which has initially been proposed by the authors intending to give nuclear industry a leap of progress in the system reliability, performance improvement, and cost reduction. The concept of the System Based Code intends to give a theoretical procedure to optimize the reliability of the system by administrating every related engineering requirement throughout the life of the system from design to decommissioning. (authors)

  17. RSA-Based Secret Handshakes

    Vergnaud , Damien

    2006-01-01

    A secret handshake mechanism allows two entities, members of a same group, to authenticate each other secretly. This primitive was introduced recently by Balfanz, Durfee, Shankar, Smetters, Staddon and Wong and, so far, all the schemes proposed are based on discrete log systems. This paper proposes three new secret handshake protocols secure against active impersonator and detector adversaries. Inspired by two RSA-based key agreement protocols introduced by Okamoto and Tanaka in 1989 and Gira...

  18. Evidence-based cancer imaging

    Shinagare, Atul B.; Khorasani, Ramin [Dept. of Radiology, Brigham and Women' s Hospital, Boston (Korea, Republic of)

    2017-01-15

    With the advances in the field of oncology, imaging is increasingly used in the follow-up of cancer patients, leading to concerns about over-utilization. Therefore, it has become imperative to make imaging more evidence-based, efficient, cost-effective and equitable. This review explores the strategies and tools to make diagnostic imaging more evidence-based, mainly in the context of follow-up of cancer patients.

  19. Evidence based medical imaging (EBMI)

    Smith, Tony

    2008-01-01

    Background: The evidence based paradigm was first described about a decade ago. Previous authors have described a framework for the application of evidence based medicine which can be readily adapted to medical imaging practice. Purpose: This paper promotes the application of the evidence based framework in both the justification of the choice of examination type and the optimisation of the imaging technique used. Methods: The framework includes five integrated steps: framing a concise clinical question; searching for evidence to answer that question; critically appraising the evidence; applying the evidence in clinical practice; and, evaluating the use of revised practices. Results: This paper illustrates the use of the evidence based framework in medical imaging (that is, evidence based medical imaging) using the examples of two clinically relevant case studies. In doing so, a range of information technology and other resources available to medical imaging practitioners are identified with the intention of encouraging the application of the evidence based paradigm in radiography and radiology. Conclusion: There is a perceived need for radiographers and radiologists to make greater use of valid research evidence from the literature to inform their clinical practice and thus provide better quality services

  20. Entanglement in mutually unbiased bases

    Wiesniak, M; Zeilinger, A [Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna (Austria); Paterek, T, E-mail: tomasz.paterek@nus.edu.sg [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore (Singapore)

    2011-05-15

    One of the essential features of quantum mechanics is that most pairs of observables cannot be measured simultaneously. This phenomenon manifests itself most strongly when observables are related to mutually unbiased bases. In this paper, we shed some light on the connection between mutually unbiased bases and another essential feature of quantum mechanics, quantum entanglement. It is shown that a complete set of mutually unbiased bases of a bipartite system contains a fixed amount of entanglement, independent of the choice of the set. This has implications for entanglement distribution among the states of a complete set. In prime-squared dimensions we present an explicit experiment-friendly construction of a complete set with a particularly simple entanglement distribution. Finally, we describe the basic properties of mutually unbiased bases composed of product states only. The constructions are illustrated with explicit examples in low dimensions. We believe that the properties of entanglement in mutually unbiased bases may be one of the ingredients to be taken into account to settle the question of the existence of complete sets. We also expect that they will be relevant to applications of bases in the experimental realization of quantum protocols in higher-dimensional Hilbert spaces.

  1. A comprehensive physiologically based pharmacokinetic ...

    Published physiologically based pharmacokinetic (PBPK) models from peer-reviewed articles are often well-parameterized, thoroughly-vetted, and can be utilized as excellent resources for the construction of models pertaining to related chemicals. Specifically, chemical-specific parameters and in vivo pharmacokinetic data used to calibrate these published models can act as valuable starting points for model development of new chemicals with similar molecular structures. A knowledgebase for published PBPK-related articles was compiled to support PBPK model construction for new chemicals based on their close analogues within the knowledgebase, and a web-based interface was developed to allow users to query those close analogues. A list of 689 unique chemicals and their corresponding 1751 articles was created after analysis of 2,245 PBPK-related articles. For each model, the PMID, chemical name, major metabolites, species, gender, life stages and tissue compartments were extracted from the published articles. PaDEL-Descriptor, a Chemistry Development Kit based software, was used to calculate molecular fingerprints. Tanimoto index was implemented in the user interface as measurement of structural similarity. The utility of the PBPK knowledgebase and web-based user interface was demonstrated using two case studies with ethylbenzene and gefitinib. Our PBPK knowledgebase is a novel tool for ranking chemicals based on similarities to other chemicals associated with existi

  2. Home-based versus centre-based cardiac rehabilitation.

    Taylor, Rod S; Dalal, Hayes; Jolly, Kate; Moxham, Tiffany; Zawada, Anna

    2010-01-20

    The burden of cardiovascular disease world-wide is one of great concern to patients and health care agencies alike. Traditionally centre-based cardiac rehabilitation (CR) programmes are offered to individuals after cardiac events to aid recovery and prevent further cardiac illness. Home-based cardiac rehabilitation programmes have been introduced in an attempt to widen access and participation. To determine the effectiveness of home-based cardiac rehabilitation programmes compared with supervised centre-based cardiac rehabilitation on mortality and morbidity, health-related quality of life and modifiable cardiac risk factors in patients with coronary heart disease. We updated the search of a previous review by searching the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2007, Issue 4), MEDLINE, EMBASE and CINAHL from 2001 to January 2008. We checked reference lists and sought advice from experts. No language restrictions were applied. Randomised controlled trials (RCTs) that compared centre-based cardiac rehabilitation (e.g. hospital, gymnasium, sports centre) with home-based programmes, in adults with myocardial infarction, angina, heart failure or who had undergone revascularisation. Studies were selected independently by two reviewers, and data extracted by a single reviewer and checked by a second one. Authors were contacted where possible to obtain missing information. Twelve studies (1,938 participants) met the inclusion criteria. The majority of studies recruited a lower risk patient following an acute myocardial infarction (MI) and revascularisation. There was no difference in outcomes of home- versus centre-based cardiac rehabilitation in mortality risk ratio (RR) was1.31 (95% confidence interval (C) 0.65 to 2.66), cardiac events, exercise capacity standardised mean difference (SMD) -0.11 (95% CI -0.35 to 0.13), as well as in modifiable risk factors (systolic blood pressure; diastolic blood pressure; total cholesterol

  3. Micro reflectance difference techniques: Optical probes for surface exploration

    Lastras-Martinez, L.F.; Del Pozo-Zamudio, O.; Herrera-Jasso, R.; Ulloa-Castillo, N.A.; Balderas-Navarro, R.E.; Ortega-Gallegos, J.; Lastras-Martinez, A. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico)

    2012-06-15

    Micro reflectance difference spectroscopy ({mu}-RDS) is a promising tool for the in-situ and ex-situ characterization of semiconductors surfaces and interfaces. We discuss and compare two different approaches used to measure {mu}-RD spectra. One is based on a charge-coupled device (CCD) camera, while the other uses a laser and a XY translation stage. To show the performance of these systems, we have measured surface optical anisotropies of GaSb(001) sample on which anisotropic strains have been generated by preferential mechanical polishing along [110] and [1 anti 10] directions. The spectrometers are complementary and the selection of one of them depends on the sample to be investigated and on experimental conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Polarization contrast linear spectroscopies for cubic semiconductors under stress: macro- and micro-reflectance difference spectroscopies

    Lastras-Martinez, L.F.; Balderas-Navarro, R.E.; Castro-Garcia, R.; Herrera-Jasso, R.; Lastras-Martinez, A. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico); Chavira-Rodriguez, M. [Departamento de Fisico Matematicas, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico)

    2011-01-15

    The technique to measure optical anisotropies (OA) in cubic semiconductors is termed either reflectance difference spectroscopy (RDS) or reflectance anisotropy spectroscopy (RAS). In this paper we report on the application of RDS/RAS to a number of cubic semiconductors. We discuss RD spectra of GaAs, Si, CdTe, GaP, InP and GaSb (001) surfaces, induced by an uniaxial stress applied along [110] crystal directions. We show that all RD spectra can be explained in terms of a phenomenological model based on a perturbative Hamiltonian. We further report on measurements of spatial-resolved RDS measurements of GaAs employing a newly developed micro-RD spectrometer with a spatial resolution of 5 {mu}m. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Effect of antimony nano-scale surface-structures on a GaSb/AlAsSb distributed Bragg reflector

    Husaini, S.; Shima, D.; Ahirwar, P.; Rotter, T. J.; Hains, C. P.; Dang, T.; Bedford, R. G.; Balakrishnan, G.

    2013-01-01

    Effects of antimony crystallization on the surface of GaSb during low temperature molecular beam epitaxy growth are investigated. The geometry of these structures is studied via transmission electron and atomic force microscopies, which show the surface metal forms triangular-shaped, elongated nano-wires with a structured orientation composed entirely of crystalline antimony. By depositing antimony on a GaSb/AlAsSb distributed Bragg reflector, the field is localized within the antimony layer. Polarization dependent transmission measurements are carried out on these nano-structures deposited on a GaSb/AlAsSb distributed Bragg reflector. It is shown that the antimony-based structures at the surface favor transmission of light polarized perpendicular to the wires.

  6. Type II GaSb/GaAs quantum dot/ring stacks with extended photoresponse for efficient solar cells

    Carrington, Peter James, E-mail: p.carrington@lancaster.ac.uk [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Mahajumi, Abu Syed [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Wagener, Magnus C.; Botha, Johannes Reinhardt [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Zhuang Qian; Krier, Anthony [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2012-05-15

    We report on the fabrication of GaAs based p-i-n solar cells containing 5 and 10 layers of type II GaSb quantum rings grown by molecular beam epitaxy. Solar cells containing quantum rings show improved efficiency at longer wavelengths into the near-IR extending up to 1500 nm and show enhanced short-circuit current under 1 sun illumination compared to a GaAs control cell. A reduction in the open-circuit voltage is observed due to the build-up of internal strain. The MBE growth, formation and photoluminescence of single and stacked layers of GaSb/GaAs quantum rings are also presented.

  7. David Adler Lectureship Award Talk: III-V Semiconductor Nanowires on Silicon for Future Devices

    Riel, Heike

    Bottom-up grown nanowires are very attractive materials for direct integration of III-V semiconductors on silicon thus opening up new possibilities for the design and fabrication of nanoscale devices for electronic, optoelectronic as well as quantum information applications. Template-Assisted Selective Epitaxy (TASE) allows the well-defined and monolithic integration of complex III-V nanostructures and devices on silicon. Achieving atomically abrupt heterointerfaces, high crystal quality and control of dimension down to 1D nanowires enabled the demonstration of FETs and tunnel devices based on In(Ga)As and GaSb. Furthermore, the strong influence of strain on nanowires as well as results on quantum transport studies of InAs nanowires with well-defined geometry will be presented.

  8. Type II GaSb/GaAs quantum dot/ring stacks with extended photoresponse for efficient solar cells

    Carrington, Peter James; Mahajumi, Abu Syed; Wagener, Magnus C.; Botha, Johannes Reinhardt; Zhuang Qian; Krier, Anthony

    2012-01-01

    We report on the fabrication of GaAs based p–i–n solar cells containing 5 and 10 layers of type II GaSb quantum rings grown by molecular beam epitaxy. Solar cells containing quantum rings show improved efficiency at longer wavelengths into the near-IR extending up to 1500 nm and show enhanced short-circuit current under 1 sun illumination compared to a GaAs control cell. A reduction in the open-circuit voltage is observed due to the build-up of internal strain. The MBE growth, formation and photoluminescence of single and stacked layers of GaSb/GaAs quantum rings are also presented.

  9. From conventional software based systems to knowledge based systems

    Bologna, S.

    1995-01-01

    Even if todays nuclear power plants have a very good safety record, there is a continuous search for still improving safety. One direction of this effort address operational safety, trying to improve the handling of disturbances and accidents partly by further automation, partly by creating a better control room environment, providing the operator with intelligent support systems to help in the decision making process. Introduction of intelligent computerised operator support systems has proved to be an efficient way of improving the operators performance. A number of systems have been developed worldwide, assisting in tasks like process fault detection and diagnosis, selection and implementation of proper remedial actions. Unfortunately, the use of Knowledge Based Systems (KBSs), introduces a new dimension to the problem of the licensing process. KBSs, despite the different technology employed, are still nothing more than a computer program. Unfortunately, quite a few people building knowledge based systems seem to ignore the many good programming practices that have evolved over the years for producing traditional computer programs. In this paper the author will try to point out similarities and differences between conventional software based systems, and knowledge based systems, introducing also the concept of model based reasoning. (orig.) (25 refs., 2 figs.)

  10. From scientifically based research to evidence based learning

    Rosa Cera

    2016-02-01

    Full Text Available This essay is a reflection on the peculiarities of the scientifically based research and on the distinctive elements of the EBL (evidence based learning, methodology used in the study on the “Relationship between Metacognition, Self-efficacy and Self-regulation in Learning”. The EBL method, based on the standardization of data, explains how the students’ learning experience can be considered as a set of “data” and can be used to explain how and when the research results can be considered generalizable and transferable to other learning situations. The reflections present in this study have also allowed us to illustrate the impact that its results have had on the micro and macro level of reality. They helped to fill in the gaps concerning the learning/teaching processes, contributed to the enrichment of the scientific literature on this subject and allowed to establish standards through rigorous techniques such as systematic reviews and meta-analysis.

  11. Nasal base narrowing: the combined alar base excision technique.

    Foda, Hossam M T

    2007-01-01

    To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

  12. Generalized eigenvalue based spectrum sensing

    Shakir, Muhammad

    2012-01-01

    Spectrum sensing is one of the fundamental components in cognitive radio networks. In this chapter, a generalized spectrum sensing framework which is referred to as Generalized Mean Detector (GMD) has been introduced. In this context, we generalize the detectors based on the eigenvalues of the received signal covariance matrix and transform the eigenvalue based spectrum sensing detectors namely: (i) the Eigenvalue Ratio Detector (ERD) and two newly proposed detectors which are referred to as (ii) the GEometric Mean Detector (GEMD) and (iii) the ARithmetic Mean Detector (ARMD) into an unified framework of generalize spectrum sensing. The foundation of the proposed framework is based on the calculation of exact analytical moments of the random variables of the decision threshold of the respective detectors. The decision threshold has been calculated in a closed form which is based on the approximation of Cumulative Distribution Functions (CDFs) of the respective test statistics. In this context, we exchange the analytical moments of the two random variables of the respective test statistics with the moments of the Gaussian (or Gamma) distribution function. The performance of the eigenvalue based detectors is compared with the several traditional detectors including the energy detector (ED) to validate the importance of the eigenvalue based detectors and the performance of the GEMD and the ARMD particularly in realistic wireless cognitive radio network. Analytical and simulation results show that the newly proposed detectors yields considerable performance advantage in realistic spectrum sensing scenarios. Moreover, the presented results based on proposed approximation approaches are in perfect agreement with the empirical results. © 2012 Springer Science+Business Media Dordrecht.

  13. Characteristic properties of Fibonacci-based mutually unbiased bases

    Seyfarth, Ulrich; Alber, Gernot [Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Ranade, Kedar [Institut fuer Quantenphysik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)

    2012-07-01

    Complete sets of mutually unbiased bases (MUBs) offer interesting applications in quantum information processing ranging from quantum cryptography to quantum state tomography. Different construction schemes provide different perspectives on these bases which are typically also deeply connected to various mathematical research areas. In this talk we discuss characteristic properties resulting from a recently established connection between construction methods for cyclic MUBs and Fibonacci polynomials. As a remarkable fact this connection leads to construction methods which do not involve any relations to mathematical properties of finite fields.

  14. Orthogonally Based Digital Content Management Applicable to Projects-bases

    Daniel MILODIN

    2009-01-01

    Full Text Available There is defined the concept of digital content. The requirements of an efficient management of the digital content are established. There are listed the quality characteristics of digital content. Orthogonality indicators of digital content are built up. They are meant to measure the image, the sound as well as the text orthogonality as well. Projects-base concept is introduced. There is presented the model of structuring the content in order to maximize orthogonality via a convergent iterative process. The model is instantiated for the digital content of a projects-base. It is introduced the application used to test the model. The paper ends with conclusions.

  15. Thermal insulation coating based on water-based polymer dispersion

    Panchenko Iuliia

    2018-01-01

    Full Text Available For Russia, due to its long winter period, improvement of thermal insulation properties of envelope structures by applying thermal insulation paint and varnish coating to its inner surface is considered perspective. Thermal insulation properties of such coatings are provided by adding aluminosilicate microspheres and aluminum pigment to their composition. This study was focused on defining the effect of hollow aluminosilicate microspheres and aluminum pigment on the paint thermal insulation coating based on water-based polymer dispersion and on its optimum filling ratio. The optimum filling ratio was determined using the method of critical pigment volume concentration (CPVC. The optimum filling ratio was found equal to 55%.

  16. Temperature effect on the growth of Au-free InAs and InAs/GaSb heterostructure nanowires on Si substrate by MOCVD

    Kakkerla, Ramesh Kumar; Anandan, Deepak; Hsiao, Chih-Jen; Yu, Hung Wei; Singh, Sankalp Kumar; Chang, Edward Yi

    2018-05-01

    We demonstrate the growth of vertically aligned Au-free InAs and InAs/GaSb heterostructure nanowires on Si (1 1 1) substrate by Metal Organic Chemical Vapor Deposition (MOCVD). The effect of growth temperature on the morphology and growth rate of the InAs and InAs/GaSb heterostructure nanowires (NWs) is investigated. Control over diameter and length of the InAs NWs and the GaSb shell thickness was achieved by using growth temperature. As the GaSb growth temperature increase, GaSb radial growth rate increases due to the increase in alkyl decomposition at the substrate surface. Diffusivity of the adatoms increases as the GaSb growth temperature increase which results in tapered GaSb shell growth. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) measurements revealed that the morphology and shell thickness can be tuned by the growth temperature. Electron microscopy also shows the formation of GaSb both in radial and axial directions outside the InAs NW core can be controlled by the growth temperature. This study demonstrates the control over InAs NWs growth and the GaSb shell thickness can be achieved through proper growth temperature control, such technique is essential for the growth of nanowire for future nano electronic devices, such as Tunnel FET.

  17. Automated knowledge-base refinement

    Mooney, Raymond J.

    1994-01-01

    Over the last several years, we have developed several systems for automatically refining incomplete and incorrect knowledge bases. These systems are given an imperfect rule base and a set of training examples and minimally modify the knowledge base to make it consistent with the examples. One of our most recent systems, FORTE, revises first-order Horn-clause knowledge bases. This system can be viewed as automatically debugging Prolog programs based on examples of correct and incorrect I/O pairs. In fact, we have already used the system to debug simple Prolog programs written by students in a programming language course. FORTE has also been used to automatically induce and revise qualitative models of several continuous dynamic devices from qualitative behavior traces. For example, it has been used to induce and revise a qualitative model of a portion of the Reaction Control System (RCS) of the NASA Space Shuttle. By fitting a correct model of this portion of the RCS to simulated qualitative data from a faulty system, FORTE was also able to correctly diagnose simple faults in this system.

  18. Content Based Searching for INIS

    Jain, V.; Jain, R.K.

    2016-01-01

    Full text: Whatever a user wants is available on the internet, but to retrieve the information efficiently, a multilingual and most-relevant document search engine is a must. Most current search engines are word based or pattern based. They do not consider the meaning of the query posed to them; purely based on the keywords of the query; no support of multilingual query and and dismissal of nonrelevant results. Current information-retrieval techniques either rely on an encoding process, using a certain perspective or classification scheme, to describe a given item, or perform a full-text analysis, searching for user-specified words. Neither case guarantees content matching because an encoded description might reflect only part of the content and the mere occurrence of a word does not necessarily reflect the document’s content. For general documents, there doesn’t yet seem to be a much better option than lazy full-text analysis, by manually going through those endless results pages. In contrast to this, new search engine should extract the meaning of the query and then perform the search based on this extracted meaning. New search engine should also employ Interlingua based machine translation technology to present information in the language of choice of the user. (author

  19. Case-Base Maintenance for CCBR-Based Process Evolution

    Weber, B.; Reichert, M.U.; Wild, W.; Roth-Berghofer, T.; Göker, M.H.; Güvenir, H.A.

    2006-01-01

    The success of a company more and more depends on its ability to flexibly and quickly react to changes. Combining process management techniques and conversational case-based reasoning (CCBR) allows for flexibly aligning the business processes to new requirements by providing integrated process life

  20. Mo-Si-B-Based Coatings for Ceramic Base Substrates

    Perepezko, John Harry (Inventor); Sakidja, Ridwan (Inventor); Ritt, Patrick (Inventor)

    2015-01-01

    Alumina-containing coatings based on molybdenum (Mo), silicon (Si), and boron (B) ("MoSiB coatings") that form protective, oxidation-resistant scales on ceramic substrate at high temperatures are provided. The protective scales comprise an aluminoborosilicate glass, and may additionally contain molybdenum. Two-stage deposition methods for forming the coatings are also provided.

  1. Event-Based Conceptual Modeling

    Bækgaard, Lars

    The paper demonstrates that a wide variety of event-based modeling approaches are based on special cases of the same general event concept, and that the general event concept can be used to unify the otherwise unrelated fields of information modeling and process modeling. A set of event......-based modeling approaches are analyzed and the results are used to formulate a general event concept that can be used for unifying the seemingly unrelated event concepts. Events are characterized as short-duration processes that have participants, consequences, and properties, and that may be modeled in terms...... of information structures. The general event concept can be used to guide systems analysis and design and to improve modeling approaches....

  2. Nickel and cobalt base alloys

    Houlle, P.

    1994-01-01

    Nickel base alloys have a good resistance to pitting, cavernous or cracks corrosion. Nevertheless, all the nickel base alloys are not equivalent. Some differences exit between all the families (Ni, Ni-Cu, Ni-Cr-Fe, Ni-Cr-Fe-Mo/W-Cu, Ni-Cr-Mo/W, Ni-Mo). Cobalt base alloys in corrosive conditions are generally used for its wear and cracks resistance, with a compromise to its localised corrosion resistance properties. The choice must be done from the perfect knowledge of the corrosive medium and of the alloys characteristics (chemical, metallurgical). A synthesis of the corrosion resistance in three medium (6% FeCl 3 , 4% NaCl + 1% HCl + 0.1% Fe 2 (SO 4 ) 3 , 11.5% H 2 SO 4 + 1.2% HCl + 1% Fe 2 (SO 4 ) 3 + 1% CuCl 2 ) is presented. (A.B.). 11 refs., 1 fig., 12 tabs

  3. Laser-powered lunar base

    Costen, R.; Humes, D.H.; Walker, G.H.; Williams, M.D.; Deyoung, R.J.

    1989-01-01

    The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized

  4. Mitochondrial base excision repair assays

    Maynard, Scott; de Souza-Pinto, Nadja C; Scheibye-Knudsen, Morten

    2010-01-01

    The main source of mitochondrial DNA (mtDNA) damage is reactive oxygen species (ROS) generated during normal cellular metabolism. The main mtDNA lesions generated by ROS are base modifications, such as the ubiquitous 8-oxoguanine (8-oxoG) lesion; however, base loss and strand breaks may also occur....... Many human diseases are associated with mtDNA mutations and thus maintaining mtDNA integrity is critical. All of these lesions are repaired primarily by the base excision repair (BER) pathway. It is now known that mammalian mitochondria have BER, which, similarly to nuclear BER, is catalyzed by DNA...... glycosylases, AP endonuclease, DNA polymerase (POLgamma in mitochondria) and DNA ligase. This article outlines procedures for measuring oxidative damage formation and BER in mitochondria, including isolation of mitochondria from tissues and cells, protocols for measuring BER enzyme activities, gene...

  5. Tune-Based Halo Diagnostics

    Cameron, Peter

    2003-01-01

    Tune-based halo diagnostics can be divided into two categories -- diagnostics for halo prevention, and diagnostics for halo measurement. Diagnostics for halo prevention are standard fare in accumulators, synchrotrons, and storage rings, and again can be divided into two categories -- diagnostics to measure the tune distribution (primarily to avoid resonances), and diagnostics to identify instabilities (which will not be discussed here). These diagnostic systems include kicked (coherent) tune measurement, phase-locked loop (PLL) tune measurement, Schottky tune measurement, beam transfer function (BTF) measurements, and measurement of transverse quadrupole mode envelope oscillations. We refer briefly to tune diagnostics used at RHIC and intended for the SNS, and then present experimental results. Tune-based diagnostics for halo measurement (as opposed to prevention) are considerably more difficult. We present one brief example of tune-based halo measurement

  6. Solar Panel based Milk Pasteurization

    Nielsen, Kirsten Mølgaard; Pedersen, Tom Søndergaard

    This paper treats the subject of analysis, design and development of the control system for a solar panel based milk pasteurization system to be used in small villages in Tanzania. The analysis deals with the demands for an acceptable pasteurization, the varying energy supply and the low cost, low...... complexity, simple user interface and high reliability demands. Based on these demands a concept for the pasteurization system is established and a control system is developed. A solar panel has been constructed and the energy absorption has been tested in Tanzania. Based on the test, the pasteurization...... system is dimensioned. A functional prototype of the pasteurization facility with a capacity of 200 l milk/hour has been developed and tested. The system is prepared for solar panels as the main energy source and is ready for a test in Tanzania....

  7. Solar Panel based Milk Pasteurization

    Nielsen, Kirsten Mølgaard; Pedersen, Tom Søndergaard

    2002-01-01

    This paper treats the subject of analysis, design and development of the control system for a solar panel based milk pasteurization system to be used in small villages in Tanzania. The analysis deals with the demands for an acceptable pasteurization, the varying energy supply and the low cost, low...... complexity, simple user interface and high reliability demands. Based on these demands a concept for the pasteurization system is established and a control system is developed. A solar panel has been constructed and the energy absorption has been tested in Tanzania. Based on the test, the pasteurization...... system is dimensioned. A functional prototype of the pasteurization facility with a capacity of 200 l milk/hour has been developed and tested. The system is prepared for solar panels as the main energy source and is ready for a test in Tanzania....

  8. Home-based COPD psychoeducation

    Bove, D G; Midtgaard, J; Kaldan, G

    2017-01-01

    in reducing symptoms of anxiety and increasing mastery of dyspnoea in patients with advanced chronic obstructive pulmonary disease (COPD). However, we do not know if the intervention is perceived as meaningful and applicable in the everyday life of patients with advanced COPD. METHODS: We conducted a nested......OBJECTIVE: To explore the patients' experiences of a minimal home-based psychoeducative intervention aimed at reducing symptoms of anxiety. BACKGROUND: In a randomised controlled trial (RCT) we have shown that a minimal home-based and nurse-led psychoeducative intervention has a significant effect...... post-trial qualitative study. The study methodology was Interpretive Description as described by Thorne. The study was based on semi-structured interviews with twenty patients from the RCT intervention group i.g. home-living people with a diagnosis of advanced COPD and symptoms of anxiety. RESULTS...

  9. Thiophene-Based Organic Semiconductors.

    Turkoglu, Gulsen; Cinar, M Emin; Ozturk, Turan

    2017-10-24

    Thiophene-based π-conjugated organic small molecules and polymers are the research subject of significant current interest owing to their potential use as organic semiconductors in material chemistry. Despite simple and similar molecular structures, the hitherto reported properties of thiophene-based organic semiconductors are rather diverse. Design of high performance organic semiconducting materials requires a thorough understanding of inter- and intra-molecular interactions, solid-state packing, and the influence of both factors on the charge carrier transport. In this chapter, thiophene-based organic semiconductors, which are classified in terms of their chemical structures and their structure-property relationships, are addressed for the potential applications as organic photovoltaics (OPVs), organic field-effect transistors (OFETs) and organic light emitting diodes (OLEDs).

  10. The Nordic Chernobyl data base

    Walmod-Larsen, O.

    1990-01-01

    The NORDIC CHERNOBYL DATA BASE (NCDB) is established for scientific purposes. The aim is to collect valid data on radiation and radioactivity resulting from measurements made in the Nordic countries particularly after the Chernobyl accident. All information is stored in the so called C-base data system, which can handle input from a variety of sources, including multiple information on each sample. The system permits output to various other computer programs for furhter data treatment. The data base can be used from personal computers and as well as from VAX-computers. Data can be displayed in time- or geographical scales and they can be arranged so as to fit different system for statistical analysis. (author)

  11. Isotope-based quantum information

    G Plekhanov, Vladimir

    2012-01-01

    The present book provides to the main ideas and techniques of the rapid progressing field of quantum information and quantum computation using isotope - mixed materials. It starts with an introduction to the isotope physics and then describes of the isotope - based quantum information and quantum computation. The ability to manipulate and control electron and/or nucleus spin in semiconductor devices provides a new route to expand the capabilities of inorganic semiconductor-based electronics and to design innovative devices with potential application in quantum computing. One of the major challenges towards these objectives is to develop semiconductor-based systems and architectures in which the spatial distribution of spins and their properties can be controlled. For instance, to eliminate electron spin decoherence resulting from hyperfine interaction due to nuclear spin background, isotopically controlled devices are needed (i.e., nuclear spin-depleted). In other emerging concepts, the control of the spatial...

  12. Cellular-based preemption system

    Bachelder, Aaron D. (Inventor)

    2011-01-01

    A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

  13. Architecture for Absorption Based Heaters

    Moghaddam, Saeed; Chugh, Devesh

    2018-04-24

    An absorption based heater is constructed on a fluid barrier heat exchanging plate such that it requires little space in a structure. The absorption based heater has a desorber, heat exchanger, and absorber sequentially placed on the fluid barrier heat exchanging plate. The vapor exchange faces of the desorber and the absorber are covered by a vapor permeable membrane that is permeable to a refrigerant vapor but impermeable to an absorbent. A process fluid flows on the side of the fluid barrier heat exchanging plate opposite the vapor exchange face through the absorber and subsequently through the heat exchanger. The absorption based heater can include a second plate with a condenser situated parallel to the fluid barrier heat exchanging plate and opposing the desorber for condensation of the refrigerant for additional heating of the process fluid.

  14. Optical Fiber Grating based Sensors

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser...

  15. A cement based syntactic foam

    Li Guoqiang; Muthyala, Venkata D.

    2008-01-01

    In this study, a cement based syntactic foam core was proposed and experimentally investigated for composite sandwich structures. This was a multi-phase composite material with microballoon dispersed in a rubber latex toughened cement paste matrix. A trace amount of microfiber was also incorporated to increase the number of mechanisms for energy absorption and a small amount of nanoclay was added to improve the crystal structure of the hydrates. Three groups of cement based syntactic foams with varying cement content were investigated. A fourth group of specimens containing pure cement paste were also prepared as control. Each group contained 24 beam specimens. The total number of beam specimens was 96. The dimension of each beam was 30.5 cm x 5.1 cm x 1.5 cm. Twelve foam specimens from each group were wrapped with plain woven 7715 style glass fabric reinforced epoxy to prepare sandwich beams. Twelve cubic foam specimens, three from each group, with a side length of 5.1 cm, were also prepared. Three types of testing, low velocity impact test and four-point bending test on the beam specimens and compression test on the cubic specimens, were conducted to evaluate the impact energy dissipation, stress-strain behavior, and residual strength. Scanning electron microscope (SEM) was also used to examine the energy dissipation mechanisms in the micro-length scale. It was found that the cement based syntactic foam has a higher capacity for dissipating impact energy with an insignificant reduction in strength as compared to the control cement paste core. When compared to a polymer based foam core having similar compositions, it was found that the cement based foam has a comparable energy dissipation capacity. The developed cement based syntactic foam would be a viable alternative for core materials in impact-tolerant composite sandwich structures

  16. Technology base for microgravity horticulture

    Sauer, R. L.; Magnuson, J. W.; Scruby, R. R.; Scheld, H. W.

    1987-01-01

    Advanced microgravity plant biology research and life support system development for the spacecraft environment are critically hampered by the lack of a technology base. This inadequacy stems primarily from the fact that microgravity results in a lack of convective currents and phase separation as compared to the one gravity environment. A program plan is being initiated to develop this technology base. This program will provide an iterative flight development effort that will be closely integrated with both basic science investigations and advanced life support system development efforts incorporating biological processes. The critical considerations include optimum illumination methods, root aeration, root and shoot support, and heat rejection and gas exchange in the plant canopy.

  17. Pheromone based alternative route planning

    Liangbing Feng

    2016-08-01

    Full Text Available In this work, we propose an improved alternative route calculation based on alternative figures, which is suitable for practical environments. The improvement is based on the fact that the main traffic route is the road network skeleton in a city. Our approach using nodes may generate a higher possibility of overlapping. We employ a bidirectional Dijkstra algorithm to search the route. To measure the quality of an Alternative Figures (AG, three quotas are proposed. The experiment results indicate that the improved algorithm proposed in this paper is more effective than others.

  18. NMR-based milk metabolomics

    Sundekilde, Ulrik; Larsen, Lotte Bach; Bertram, Hanne Christine S.

    2013-01-01

    and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including applications linking...... compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining...

  19. Case-based medical informatics

    Arocha José F

    2004-11-01

    Full Text Available Abstract Background The "applied" nature distinguishes applied sciences from theoretical sciences. To emphasize this distinction, we begin with a general, meta-level overview of the scientific endeavor. We introduce the knowledge spectrum and four interconnected modalities of knowledge. In addition to the traditional differentiation between implicit and explicit knowledge we outline the concepts of general and individual knowledge. We connect general knowledge with the "frame problem," a fundamental issue of artificial intelligence, and individual knowledge with another important paradigm of artificial intelligence, case-based reasoning, a method of individual knowledge processing that aims at solving new problems based on the solutions to similar past problems. We outline the fundamental differences between Medical Informatics and theoretical sciences and propose that Medical Informatics research should advance individual knowledge processing (case-based reasoning and that natural language processing research is an important step towards this goal that may have ethical implications for patient-centered health medicine. Discussion We focus on fundamental aspects of decision-making, which connect human expertise with individual knowledge processing. We continue with a knowledge spectrum perspective on biomedical knowledge and conclude that case-based reasoning is the paradigm that can advance towards personalized healthcare and that can enable the education of patients and providers. We center the discussion on formal methods of knowledge representation around the frame problem. We propose a context-dependent view on the notion of "meaning" and advocate the need for case-based reasoning research and natural language processing. In the context of memory based knowledge processing, pattern recognition, comparison and analogy-making, we conclude that while humans seem to naturally support the case-based reasoning paradigm (memory of past experiences

  20. Space construction base control system

    1978-01-01

    Aspects of an attitude control system were studied and developed for a large space base that is structurally flexible and whose mass properties change rather dramatically during its orbital lifetime. Topics of discussion include the following: (1) space base orbital pointing and maneuvering; (2) angular momentum sizing of actuators; (3) momentum desaturation selection and sizing; (4) multilevel control technique applied to configuration one; (5) one-dimensional model simulation; (6) N-body discrete coordinate simulation; (7) structural analysis math model formulation; and (8) discussion of control problems and control methods.