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Sample records for dans sic obtenues

  1. Phonologie et morphosyntaxe de l’anglais dans un produit SIC : le premier module de MACAO Phonologie et morphosyntaxe de l’anglais dans un produit SIC : le premier module de MACAO

    Directory of Open Access Journals (Sweden)

    Laurence Vincent-Durroux

    2002-12-01

    Full Text Available La préoccupation fréquente, chez les étudiants spécialistes d’autres disciplines que l’anglais, d’améliorer leur compréhension de l’anglais oral a motivé notre démarche de création d’un produit SIC (Systèmes d’Information et de Communication : MACAO (Modules d’Aide à la Compréhension de l’Anglais Oral. Le premier module, "S’entraîner à la reconnaissance", est réalisé et l’outil informatique s’est révélé particulièrement utile pour notre projet. Dans cet article, nous faisons état des difficultés récurrentes en compréhension de l’anglais oral : elles peuvent être dues à des attentes erronées fondées sur la dissymétrie entre la langue écrite et la langue orale, mais aussi à une reconnaissance difficile de certains morphèmes par l’existence de variantes phonologiques en fonction du contexte et par la proximité phonologique de certains morphèmes. Nous présentons également comment le contenu du premier module tente d’apporter des solutions à ces difficultés : en amenant les apprenants à prendre conscience du phénomène de réduction vocalique et d’inaccentuation qui touche certaines syllabes des mots aussi bien que certains éléments monosyllabiques de l’énoncé et en proposant un entraînement à la reconnaissance de ces éléments. Le module est en cours de validation avec une phase d’évaluation.French students who have English as part of their curriculum often express the wish to improve their comprehension of oral English. This led us to envisage the creation of a CALL product: MACAO (Modules to help in the comprehension of oral English. The first module has been created: "Training oneself for recognition". The computer was particularly adequate in this prospect. In this paper we present the most frequent difficulties in the comprehension of oral English: they can be related either to erroneous expectations based on the dissymmetry between the written form and the oral

  2. Propriétés électriques et optiques de couches minces de ZnO et ZnO dopé à l'indium, obtenues par le procédé Pyrosol

    Science.gov (United States)

    Tiburcio-Silver, A.; Joubert, J. C.; Labeau, M.

    1992-07-01

    Undoped and indium-doped ZnO thin films deposited by the Pyrosol process onto soda-lime glass substrates were electrically and optically characterized. Resistivities as low as 2× 10^{-3} Ω.cm. Hall mobilities as high as 21 cm^2 V^{-1} s^{-1} and effective carrier concentrations as high as 1 × 10^{20} cm^{-3} have been obtained. Electron concentrations are always lower than indium contents on the films. Average optical transmissions on the whole visible range as high as 85% for the best conductive films have been obtained. Refractive index of layers is modified by the growth temperature and indium doping, been less dependent on doping for high deposition temperatures (better crystallinity). Haacke's figure of merit up to 5× 10^{-3} Ω^{-1} in a 500 nm thick films were obtained. Indium doping improves the time-dependent stability of the electrical properties of ZnO conducting films. Des couches minces de ZnO conducteur non dopé et dopé à l'indium, élaborées par le procédé Pyrosol sur des substrats en verre sodocalcique, ont été caractérisées du point de vue électrique et optique. Résistivités de 2× 10^{-3} Ω.cm, mobilités Hall de 21 cm^2 V^{-1} s^{-1}, et concentrations effectives des porteurs de l'ordre de 1 × 10^{20} cm^{-3} ont été obtenues. La concentration des porteurs mesurée par effet Hall est toujours inférieure à la concentration d'indium dans la couche. La transmission optique moyenne dans le visible atteint 85 % pour les films possédant la meilleure conductivité. La température de dépôt et le dopage à l'indium modifient l'indice de réfraction ; celui-ci dépend moins du dopage à des températures de dépôt élevées (meilleure cristallinité). Les meilleurs facteurs de mérite, \\varnothing_TC, sont de l'ordre de 5× 10^{-3} Ω^{-1} (épaisseur du film 5 000 Å environ). Le dopage à l'indium améliore la stabilité dans le temps des propriétés électriques des couches de ZnO.

  3. Interprétation théorique de la forme des raies obtenues par polarisation dynamique dans les solutions de radicaux libres

    OpenAIRE

    Ayant, Y.; Besson, R.; Casalegno, R.

    1980-01-01

    L'étude de la polarisation dynamique des protons de solutions de radicaux libres de type nitroxyde en champ faible faite précédemment [1] reposait sur des hypothèses dont la justification est donnée ici. Nous montrons notamment que le formalisme de populations constitue une approximation valable du formalisme plus lourd de la matrice densité. Nous utilisons alors les résultats établis pour calculer théoriquement la forme du signal nucléaire lorsque l'on fait varier la fréquence d'excitation é...

  4. SICs and Algebraic Number Theory

    Science.gov (United States)

    Appleby, Marcus; Flammia, Steven; McConnell, Gary; Yard, Jon

    2017-08-01

    We give an overview of some remarkable connections between symmetric informationally complete measurements (SIC-POVMs, or SICs) and algebraic number theory, in particular, a connection with Hilbert's 12th problem. The paper is meant to be intelligible to a physicist who has no prior knowledge of either Galois theory or algebraic number theory.

  5. Amplification à 980 nm dans une fibre dopée à l'ytterbium

    Science.gov (United States)

    Bouchier, A.; Lucas-Leclin, G.; Balembois, F.; Georges, P.

    2004-11-01

    L'ion Yb3+ dans une matrice de silice présente une section efficace d'émission maximale aux alentours de 980 nm. Cependant, la réabsorption importante à cette même longueur impose des puissances de pompage élevées. L'objet de notre étude est de concrétiser cette amplification à 980 nm, en étudiant le gain obtenu pour un signal à 976 nm et un pompage à 920 nm, en vue de réaliser le doublage de ce signal pour obtenir une source émettant dans le bleu.

  6. Fabrication and Properties of Ti3SiC2/SiC Composites

    Institute of Scientific and Technical Information of China (English)

    YIN Hongfeng; FAN Qiang; REN Yun; ZHANG Junzhan

    2008-01-01

    Ti3SiC2/SiC composites were fabricated by reactive hot pressing method. Effects of hot pressing temperature, the content and panicle size of SiC on phase composition, densification, mechanical properties and behavior of stress-strain of the composites were investigated. The results showed that:(1)Hot-pressing temperature influenced the phase composition of Ti3SiC2/SiC composites. The flexural strength and fracture toughness of composites increased with hot pressing temperature.(2)It became more difficult for the composites to densify when the content of SiC in composites increased. It need be sintered at higher temperature to get denser composite. The flexural strength and fracture toughness of composites increased when the content of SiC added in composites increased. However, when the content of SiC reached 50 wt%, the flexural strength and fracture toughness of composites decreased due to high content of pore in composites.(3)When the content of SiC was same, Ti3SiC2/SiC composites were denser while the particle size of SiC added in composites is 12.8μm compared with the composites that the particle size of SiC added is 3μm.The flexural strength and fracture toughness of composites increased with the increase of particle size of SiC added in composites.(4)Ti3SiC2/SiC composites were non-brittle fracture at room temperature.

  7. Polycrystalline SiC as source material for the growth of fluorescent SiC layers

    DEFF Research Database (Denmark)

    Kaiser, M.; Hupfer, T.; Jokubavicus, V.;

    2013-01-01

    Polycrystalline doped SiC act as source for fluorescent SiC. We have studied the growth of individual grains with different polytypes in the source material. We show an evolution and orientation of grains of different polytypes in polycrystalline SiC ingots grown by the Physical Vapor Transport...

  8. Switching Performance Evaluation of Commercial SiC Power Devices (SiC JFET and SiC MOSFET) in Relation to the Gate Driver Complexity

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    and JFETs. The recent introduction of SiC MOSFET has proved that it is possible to have highly performing SiC devices with a minimum gate driver complexity; this made SiC power devices even more attractive despite their device cost. This paper presents an analysis based on experimental results...... of the switching losses of various commercially available Si and SiC power devices rated at 1200 V (Si IGBTs, SiC JFETs and SiC MOSFETs). The comparison evaluates the reduction of the switching losses which is achievable with the introduction of SiC power devices; this includes analysis and considerations...

  9. Sporadic SICs and the Normed Division Algebras

    Science.gov (United States)

    Stacey, Blake C.

    2017-08-01

    Symmetric informationally complete quantum measurements, or SICs, are mathematically intriguing structures, which in practice have turned out to exhibit even more symmetry than their definition requires. Recently, Zhu classified all the SICs whose symmetry groups act doubly transitively. I show that lattices of integers in the complex numbers, the quaternions and the octonions yield the key parts of these symmetry groups.

  10. SiC nanowires: material and devices

    Science.gov (United States)

    Zekentes, K.; Rogdakis, K.

    2011-04-01

    SiC nanowires are of high interest since they combine the physical properties of SiC with those induced by their low dimensionality. For this reason, a large number of scientific studies have been dedicated to their fabrication and characterization as well as to their application in devices. SiC nanowires' growth involving different growth mechanisms and configurations was the main theme for the large majority of these studies. Various physical characterization methods have been employed for evaluating SiC nanowire quality. SiC nanowires with narrow-diameter (channel material. On the other hand, the grown nanowires are suitable for field-emission applications and to be used as reinforcing material in composite structures as well as for increasing the hydrophobicity of Si surfaces. All these aspects are examined in detail in different sections of this paper.

  11. Lateral boron distribution in polycrystalline SiC source materials

    DEFF Research Database (Denmark)

    Linnarsson, M. K.; Kaiser, M.; Liljedahl, R.

    2013-01-01

    Polycrystalline SiC containing boron and nitrogen are used in growth of fluorescent SiC for white LEDs. Two types of doped polycrystalline SiC have been studied in detail with secondary ion mass spectrometry: sintered SiC and poly-SiC prepared by sublimation in a physical vapor transport setup...

  12. From SICs and MUBs to Eddington

    CERN Document Server

    Bengtsson, Ingemar

    2011-01-01

    This is a survey of some very old knowledge about Mutually Unbiased Bases (MUB) and Symmetric Informationally Complete POVMs (SIC). In prime dimensions the former are closely tied to an elliptic normal curve symmetric under the Heisenberg group, while the latter are believed to be orbits under the Heisenberg group in all dimensions. In dimensions 3 and 4 the SICs are understandable in terms of elliptic curves, but a general statement escapes us. The geometry of the SICs in 3 and 4 dimensions is discussed in some detail.

  13. Effects of SiC amount on phase compositions and properties of Ti3SiC2-based composites

    Institute of Scientific and Technical Information of China (English)

    蔡艳芝; 殷小玮; 尹洪峰

    2015-01-01

    The phase compositions and properties of Ti3SiC2-based composites with SiC addition of 5%−30% in mass fraction fabricated by in-situ reaction and hot pressing sintering were studied. SiC addition effectively prevented TiC synthesis but facilitated SiC synthesis. The Ti3SiC2/TiC−SiC composite had better oxidation resistance when SiC added quantity reached 20% but poorer oxidation resistance with SiC addition under 15%than Ti3SiC2/TiC composite at higher temperatures. There were more than half of the original SiC and a few Ti3SiC2 remaining in Ti3SiC2/TiC−SiC with 20% SiC addition, but all constituents in Ti3Si2/TiC composite were oxidized after 12 h in air at 1500 °C. The oxidation scale thickness of TS30, 1505.78μm, was near a half of that of T, 2715μm, at 1500 °C for 20 h. Ti3SiC2/TiC composite had a flexural strength of 474 MPa, which was surpassed by Ti3SiC2/TiC−SiC composites when SiC added amount reached 15%. The strength reached the peak of 518 MPa at 20%SiC added amount.

  14. Luminescence de l'europium divalent dans les borates doubles BaLnB9O16(Ln=La, Gd, Y) et de l'europium trivalent dans les phosphates d'Yttrium et de gadolinium en vue d'application à la visualisation

    OpenAIRE

    Cong Tuan, Dinh

    2000-01-01

    En vue d'application à l'éclairage ou dans les dispositifs de visualisation à plama, on a étudié la luminescence de l'ion Eu2+ dans les borates BaLnB9O16 (Ln = La, Ce, Gd, Y) et de l'ion Eu3+ dans les diverses phases des systèmes Gd2O3-P2O5 et Y2O3-P2O5. Des informations sur les structures des réseaux-hôtes lorsqu'elles étaient inconnues, ont pu être obtenues par diffraction X et spectroscopie Raman. Pour Ln = Y, Gd, les borates BaLnB9O16:Eu2+ présentent une émission dans le bleu stable...; n...

  15. Lat.SIC - roum şi

    Directory of Open Access Journals (Sweden)

    Maria Iliescu

    1991-12-01

    Full Text Available In Jatina populară şi tîrzie ET 'şi' începe să fie întărit prin SIC 'astfel'. Locutiunea ET SIC putea avea sensurile 'şi astfel', 'şi apoi', 'şi imediat', 'şi deasemenea' sau nu mai şi'. Cu timpul s-a pierdut uneori determinantul ET şi SIC singur a inceput să exprime sensurile de mai sus. Astfel se explică etimologia şi accepţiunile rom. şi, conjunctie şi adverb. Se remană de asemenea că evoluţie semantica a lui SIC în română asta pînă la un punct identică cu cea din franceza veche.

  16. Microwave joining of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Silberglitt, R.; Ahmad, I.; Tian, Y.L. [FM Technologies, Inc., Fairfax, VA (United States)] [and others

    1997-04-01

    The purpose of this work is to optimize the properties of SiC-SiC joints made using microwave energy. The current focus is on identification of the most effective joining methods for scale-up to large tube assemblies, including joining using SiC produced in situ from chemical precursors. During FY 1996, a new microwave applicator was designed, fabricated and tested that provides the capability for vacuum baking of the specimens and insulation and for processing under inert environment. This applicator was used to join continuous fiber-reinforced (CFCC) SiC/SiC composites using a polymer precursor to form a SiC interlayer in situ.

  17. PHASE CHANGES ON 4H AND 6H SIC AT HIGH TEMPERATURE OXIDATION

    Directory of Open Access Journals (Sweden)

    Jan Setiawan

    2016-10-01

    Full Text Available ABSTRACT PHASE CHANGES ON 4H AND 6H SIC AT HIGH TEMPERATURE OXIDATION. The oxidation on two silicon carbide contain 6H phase and contains 6H and 4H phases has been done.  Silicon carbide is ceramic non-oxide with excellent properties that potentially used in industry.  Silicon carbide is used in nuclear industry as structure material that developed as light water reactor (LWR fuel cladding and as a coating layer in the high temperature gas-cooled reactor (HTGR fuel.  In this study silicon carbide oxidation simulation take place in case the accident in primary cooling pipe is ruptured.  Sample silicon carbide made of powder that pressed into pellet with diameter 12.7 mm and thickness 1.0 mm, then oxidized at temperature 1000 oC, 1200 oC dan 1400 oC for 1 hour.  The samples were weighted before and after oxidized.  X-ray diffraction con-ducted to the samples using Panalytical Empyrean diffractometer with Cu as X-ray source.  Diffraction pattern analysis has been done using General Structure Analysis System (GSAS software. This software was resulting the lattice parameter changes and content of SiC phases.  The result showed all of the oxidation samples undergoes weight gain.  The 6S samples showed the highest weight change at oxidation temperature 1200 oC, for the 46S samples showed increasing tendency with the oxidation temperature.  X-ray diffraction pattern analysis showed the 6S samples contain dominan phase 6H-SiC that matched to ICSD 98-001-5325 card.  Diffraction pattern on 6S showed lattice parameter, composition and crystallite size changes.  Lattice parameters changes had smaller tendency from the model and before oxidation.  However, the lowest silicon carbide composition or the highest converted into other phases up to 66.85 %, occurred at oxidation temperature 1200 oC.  The 46S samples contains two polytypes silicon car-bide.  The 6H-SiC phases matched by ICSD 98-016-4972 card and 4H-SiC phase matched by ICSD 98

  18. A Study on Fretting Wear Property of CVD SiC and Sintered SiC

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Hyun-Jin; Jang, Ki-Nam; An, Ji-Hyeong; Kim, Kyu-Tae [Dongguk University, Gyeongju (Korea, Republic of)

    2015-10-15

    Silicon Carbide is broadly used as high temperature structure material because of its high temperature tolerance and superior mechanical properties. After the Fukushima nuclear power plant accident, SiC proposed as one of the alternative materials for LWR fuel cladding to provide enhanced safety margin. Grid-to-rod fretting wear-induced fuel failure is known to occur due to flow-induced vibration of the reactor core and grid to- rod gap. In this paper, wear tests for CVD SiC plate and sintered SiC tube were performed with two types of spacer grids. Wear test of corroded and non-corroded CVD SiC plates indicate that wear resistance of corroded specimen is lower than one of non-corroded specimen in contrast with zirconium alloy cladding tube. It may be affected by rough surface of corroded specimen caused by grain boundary attack.

  19. 29 CFR 510.21 - SIC codes.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false SIC codes. 510.21 Section 510.21 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS IMPLEMENTATION OF THE MINIMUM WAGE PROVISIONS OF THE 1989 AMENDMENTS TO THE FAIR LABOR STANDARDS ACT IN PUERTO RICO...

  20. Microwave joining of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Silberglitt, R.; Ahmad, I. [FM Technologies, Inc., Fairfax, VA (United States); Black, W.M. [George Mason Univ., Fairfax, VA (United States)] [and others

    1995-05-01

    The purpose of this work is to optimize the properties of SiC-SiC joints made using microwave energy. The current focus is on optimization of time-temperature profiles, production of SiC from chemical precursors, and design of new applicators for joining of long tubes.

  1. Universal Converter Using SiC

    Energy Technology Data Exchange (ETDEWEB)

    Dallas Marckx; Brian Ratliff; Amit Jain; Matthew Jones

    2007-01-01

    The grantee designed a high power (over 1MW) inverter for use in renewable and distributed energy systems, such as PV cells, fuel cells, variable speed wind turbines, micro turbines, variable speed gensets and various energy storage methods. The inverter uses 10,000V SiC power devices which enable the use of a straight-forward topology for medium voltage (4,160VAC) without the need to cascade devices or topologies as is done in all commercial, 4,160VAC inverters today. The use of medium voltage reduces the current by nearly an order of magnitude in all current carrying components of the energy system, thus reducing size and cost. The use of SiC not only enables medium voltage, but also the use of higher temperatures and switching frequencies, further reducing size and cost. In this project, the grantee addressed several technical issues that stand in the way of success. The two primary issues addressed are the determination of real heat losses in candidate SiC devices at elevated temperature and the development of high temperature packaging for SiC devices.

  2. Passive SiC irradiation temperature monitor

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, G.E.

    1996-04-01

    A new, improved passive irradiation temperature monitoring method was examined after an irradiation test at 627{degrees}C. The method is based on the analysis of thermal diffusivity changes during postirradiation annealing of polycrystalline SiC. Based on results from this test, several advantages for using this new method rather than a method based on length or lattice parameter changes are given.

  3. EFFECT OF SiC PARTICLE SIZE ON THE MATERIAL AND MECHANICAL PROPERTIES OF MULLITE BONDED SiC CERAMICS PROCESSED BY INFILTRATION TECHNIQUE

    National Research Council Canada - National Science Library

    Sanchita Baitalik; Nijhuma Kayal; Dey Atanu; Chakrabarti Omprakash

    2014-01-01

    The influence of SiC particles size on the bonding phase content, microstructure, SiC oxidation degree, flexural strength, porosity and pore size distribution of mullitebonded porous SiC ceramics were...

  4. Synthesis of High Purity SiC Powder for High-resistivity SiC Single Crystals Growth

    Institute of Scientific and Technical Information of China (English)

    Li WANG; Xiaobu HU; Xiangang XU; Shouzheng JIANG; Lina NING; Minhua JIANG

    2007-01-01

    High purity silicon carbide (SiC) powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC.Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.

  5. Point Defects in SiC

    Science.gov (United States)

    Zvanut, Mary Ellen

    2004-03-01

    Production of high frequency, high power electronic devices using wide bandgap semiconductors has spurred renewed interest in point defects in SiC. Recent electron paramagnetic resonance (EPR) spectroscopy studies focus on centers in as-grown high purity semi-insulating substrates because intrinsic defects are thought to compensate unavoidable shallow centers, thus creating the high resistivity required. The EPR studies address the chemical/structural composition of the defects, the defect level (energy with respect to a band edge with which the defect can accept or release an electron) and thermal stability. Thus far, the positively charged carbon vacancy, the Si vacancy, a carbon-vacancy/carbon antisite pair, and several as yet-unidentified centers have been observed in as-grown electronic-grade 4H-SiC [1-3]. The talk will review the types of defects recently identified in SiC and discuss their possible relationship to compensation. The photo-induced EPR experiments used to determine defect levels will be discussed, with a particular focus on the carbon vacancy. The use of high frequency EPR to resolve the many different types of centers in SiC will also be covered. Finally, the presentation will review the thermal stability of the intrinsic defects detected in as-grown 4H SiC. 1. M. E. Zvanut and V. V. Konovalov, Appl. Phys. Lett. 80, 410 (2002). 2. N.T. Son, Z. Zolnai, and E. Janzen, Phys. Rev. B64, 2452xx (2003). 3. W.E. Carlos, E.R. Glaser, and B.V. Shanabrook, in Proceedings of the 22nd conference on Defects in Semiconductors, Aarhus, Denmark, July 2003.

  6. SiC Schottky diode electrothermal macromodel

    OpenAIRE

    Masana Nadal, Francisco

    2010-01-01

    This paper presents a SiC Schottky diode model including static, dynamic and thermal features implemented as separate parameterized blocks constructed from SPICE Analog Behavioral Modeling (ABM) controlled sources. The parameters for each block are easy to extract, even from readily available diode data sheet information. The model complexity is low thus allowing reasonably long simulation times to cope with the rather slow self heating process and yet accurate enough for practical purposes.

  7. Investigation on the Luminescent Properties of SiC

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; LI Yu-guo; SHI Li-wei; SHUN Hai-bo; XUE Cheng-shan

    2003-01-01

    Silicon carbide (SiC) is an excellent microelectronic material used to fabricate high frequency, high temperature,high power and non-volatile memory devices.But due to its indirect band gap,SiC based LED can't emit light so efficiently as GaN based LED, so people are eager to seek effective means to improve its luminescence efficiency. Amorphous SiC, porous crystalline SiC, nanometer SiC produced by CVD methods and porous SiC formed by ion implantation are investigated, and great progresses have been gained during the latest few years,which make SiC a promising material for developing OEIC.

  8. SiC Power MOSFET with Improved Gate Dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Sbrockey, Nick M; Tompa, Gary S; Spencer, Michael G; Chandrashekhar, Chandra MVS

    2010-08-23

    In this STTR program, Structured Materials Industries (SMI), and Cornell University are developing novel gate oxide technology, as a critical enabler for silicon carbide (SiC) devices. SiC is a wide bandgap semiconductor material, with many unique properties. SiC devices are ideally suited for high-power, highvoltage, high-frequency, high-temperature and radiation resistant applications. The DOE has expressed interest in developing SiC devices for use in extreme environments, in high energy physics applications and in power generation. The development of transistors based on the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) structure will be critical to these applications.

  9. Experiments on neutron-attenuation by water-lead mixtures; Etude experimentale de l'attenuation des neutrons dans les melanges plomb-eau

    Energy Technology Data Exchange (ETDEWEB)

    Beauge, R.; Millot, J.P.; Rastoin, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The penetration of fission neutrons in water-lead mixtures has been investigated in the NAIADE facility. The slopes of the thermal and fast fluxes (the latter measured with a dosimeter) remain similar when the volume proportion of water is greater than 65 per cent. For smaller water contents, the measurements show the evidence of streaming presumably due to slowing-down neutrons of energy smaller than 300 keV. (author) [French] La propagation des neutrons de fission a ete etudiee dans les melanges plomb-eau au moyen du dispositif NAIADE. La pente du flux thermique et la pente du flux rapide (obtenue au moyen d'un dosimetre) restent voisines lorsque la proportion d'eau dans le melange depasse 65 pour cent en volume. Pour des proportions inferieures les mesures mettent en evidence un 'streaming' de neutrons en ralentissement d'energie probablement inferieure a 300 keV. (auteur)

  10. 500?C SiC JFET Driver Circuits and Packaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the proposed development, SiC JFET control circuitry and normally-off SiC JFET power switch will be integrated in a single SiC chip that will provide digital...

  11. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Diffusion of Fission Product Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Jiang, Weilin

    2014-11-01

    MAX phases, such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been suggested in the literature as a possible fuel cladding material. Prior to the application, it is necessary to investigate diffusivities of fission products in the ternary compound at elevated temperatures. This study attempts to obtain relevant data and make an initial assessment for Ti3SiC2. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti3SiC2, SiC, and a dual-phase nanocomposite of Ti3SiC2/SiC synthesized at PNNL. Thermal annealing and in-situ Rutherford backscattering spectrometry (RBS) were employed to study the diffusivity of the various implanted species in the materials. In-situ RBS study of Ti3SiC2 implanted with Au ions at various temperatures was also performed. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti3SiC2 occurs during ion implantation at 873 K. Cs in Ti3SiC2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Further studies of the related materials are recommended.

  12. Effets Seebeck et Nernst dans les cuprates: Etude de la reconstruction de la surface de Fermi sous champ magnetique intense

    Science.gov (United States)

    Laliberte, Francis

    2010-06-01

    Ce memoire presente des mesures de transport thermoelectrique, les effets Seebeck et Nernst, dans une serie d'echantillons de supraconducteurs a haute temperature critique. Des resultats obtenus recemment au Laboratoire National des Champs Magnetiques Intenses a Grenoble sur La1.7Eu0.2Sr0.1 CuO4, La1.675Eu0.2Sr0.125CuO 4, La1.64Eu0.2Sr0.16CuO4, La1.74Eu0.1Sr0.16CuO4 et La 1.4Nd0.4Sr0.2CuO4 sont analyses. Une attention particuliere est accordee aux equations de la theorie semi-classique du transport et leur validite est verifiee. La procedure experimentale et les materiaux utilises pour concevoir les montages de mesures sont expliques en detail. Enfin, un chapitre est dedie a l'explication et l'interpretation des resultats de transport thermoelectrique sur YBa2Cu3O6+delta publies au cours de l'hiver 2010 dans les revues Nature et Physical Review Letters. Les donnees d'effet Seebeck dans les echantillons de La 1.8-x,Eu0.2SrxCuO 4, ou un changement de signe est observe, permettent de conclure a la presence d'une poche d'electrons dans la surface de Fermi qui domine le transport a basse temperature dans la region sous-dopee du diagramme de phase. Cette conclusion est similaire a celle obtenue par des mesures d'effet Hall dans YBa 2Cu3O6+delta et elle cadre bien dans un scenario de reconstruction de la surface de Fermi. Les donnees d'effet Nernst recueillies indiquent que la contribution des fluctuations supraconductrices est limitee a un modeste intervalle de temperature au-dessus de la temperature critique.

  13. MODELE " DEFECT POOL" ET PHOTOCONDUCTIVITE EN REGIME STATIONNAIRE DANS LE SILICIUM AMORPHE HYDROGENE (a-Si:H

    Directory of Open Access Journals (Sweden)

    AB HEDIBI

    2005-06-01

    "defect pool" (MDP. Ce calcul tient en compte les réactions d'équilibre chimique intervenant dans le mécanisme de conversion des liaisons faibles en liaisons pendantes. La réponse du matériau à une excitation optique continue est ensuite modélisée dans les conditions de quasiéquilibre du système. Les résultats de la PCS obtenues par simulation montrent un bon accord avec les résultats expérimentaux correspondants. L'interprétation de l'allure générale de la PCS en fonction de la température dans le cas du a-Si:H intrinsèque est faite en examinant la dépendance de température des différentes charges et taux de recombinaisons dans les états des queues de bande de conduction et de valence et des liaisons pendantes

  14. Advances in wide bandgap SiC for optoelectronics

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini

    2014-01-01

    Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication...

  15. Challenges in Switching SiC MOSFET without Ringing

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig

    2014-01-01

    Switching SiC MOSFET without ringing in high frequency applications is important for meeting the EMI (ElectroMagnetic Interference) standard. Achieving a clean switching waveform of SiC MOSFET without additional components is becoming a challenge. In this paper, the switching oscillation mechanis...

  16. Analisis Kebijakan dan Efektivitas Organisasi

    Directory of Open Access Journals (Sweden)

    Amir Syarifudin Kiwang

    2015-05-01

    Full Text Available Penerapan Peraturan Gubernur Nusa Tenggara Timur Nomor 8 Tahun 2011 tentang Organisasi dan Tata Kerja Unit Pelaksana Teknis Pendidikan dan Pelatihan Koperasi dan Usaha Mikro Kecil dan Menengah pada Dinas Koperasi dan Usaha Mikro Kecil dan Menengah Provinsi Nusa Tenggara Timur adalah dalam rangka untuk meningkatkan efektivitas kerja organisasi pada UPT Diklat Koperasi dan UMKM. Penelitian ini berusaha untuk melihat dampak kebijakan organisasi terhadap efektivitas organisasi dengan menggunakan enam elemen variabel dari kebijakan dan praktik manajemen. Keenam elemen tersebut adalah penetapan tujuan strategis, pencarian dan pemanfaatan sumber daya, lingkungan prestasi, proses komunikasi, kepemimpinan dan pengambilan keputusan, serta adaptasi dan inovasi organisasi. Penelitian kualitatif ini menggunakan pendekatan studi kasus. Teknik analisis data yang digunakan adalah analisis data model Miles dan Huberman, yang terdiri atas reduksi data, display/penyajian data, dan kesimpulan/verifikasi. Hasil penelitian menunjukkan bahwa efektivitas organisasi pada UPT Diklat koperasi dan UMKM belum berjalan secara baik, hal ini dapat dilihat dari beberapa hal antara lain, belum adanya tenaga spesialisasi pengelola diklat dan tenaga khusus (sarjana di bidang perkoperasian dan kondisi lingkungan kerja (lingkungan prestasi pada UPT Diklat koperasi dan UMKM yang belum efektif. Penempatan pegawai juga belum tepat, mutasi ke UPT Diklat Koperasi dan UMKM tidak memperhatikan latar belakang pendidikan dan spesialisasi/keahlian pegawai sehingga membutuhkan waktu dalam proses penyesuaian serta menurunkan jumlah pelaksanaan diklat dikarenakan keterbatasan alokasi dana.

  17. Effets de structure dans la diffusion des ions lourds

    CERN Document Server

    El-Djalil-Kadi-Hanifi, M

    2002-01-01

    Nous avons analyse les distributions angulaires de la diffusion elastique pour differents systemes a des energies proches de la barriere de Coulomb au moyen d'un potentiel semi phenomenologique. Les distributions radiales calculees au moyen de ces potentiels montrent sans ambiguite qu'aux energies proches de la barriere de Coulomb, l'absorption se produit dans un etroit domaine de distances de la surface du potentiel nucleaire. Utilisant une modelisation simple de la theorie de Feshbach du potentiel optique, nous avons calcule la contribution a l'absorption due a un nombre reduit d'etats collectifs de surface facilement excitables. L'inclusion d'un terme d'absorption phenomenologique pour decrire des processus plus peripheriques que les excitations inelastiques, nous a permis de reproduire de maniere satisfaisante les distributions angulaires experimentales de la diffusion elastique. Aux plus hautes energies (793 MeV et 1503 MeV), et pour le systeme 16O+208Pb, nous avons utilise un potentiel reel obtenu moyen...

  18. Prospects for SiC electronics and sensors

    Directory of Open Access Journals (Sweden)

    Nick G. Wright

    2008-01-01

    Full Text Available There has been substantial international research effort in the development of SiC electronics over the last ten years. With promising applications in power electronics, hostile-environment electronics, and sensors, there is considerable industrial interest in SiC as a material for electronics. However, issues relating to crystal growth and the difficulties of material processing have restricted SiC devices to relatively limited use to date. The eventual success of SiC as an electronic technology will depend on the close interplay of research in fundamental material science with progress in design of electronic devices and packaging. We review the current status of SiC electronics from a materials perspective – highlighting current difficulties and future opportunities for progress.

  19. Epitaxial sic devices for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, M; Menichelli, D.; Pini, S.; Sciortino, S. [INFN, Firenze (Italy); Firenze Univ., Firenze (Italy). Dipartimento di Energetica; Bucciolini, M. [INFN, Firenze (Italy); Firenze Univ., Firenze (Italy). Dipartimento di Fisiopatologia Clinica; Nava, F. [Modena Univ., Modena (Italy). Dipartimento di Fisica; INFN, Bologna (Italy)

    2002-07-01

    The current response of SiC on-line dosimeters to {gamma}-radiation from{sup 60}Co and {sup 167}Cs {gamma}-sources, X-photons and 22MeV electrons from linear accelerator has been investigated. The devices used are 4H-SiC epitaxial n-type layer deposited onto a 4H-SiC n{sup +} type substrate wafer doped with nitrogen. Single-pad Schottky contacts have been produced by deposition of a 1000A gold film on the epitaxial layer and ohmic contacts have been deposited on the rear substrate side. The detector has been then embedded in epoxy resin and studied in the dose and dose-rate ranges 0.1-1 Gy 0.1-10Gy/min. A signal response comparable to that of silicon standard dosimeters has been measured with the unbiased SiC device. The released charge and induced current have been observed to increase linearly respectively with the dose and dose-rate. A preliminary study on the changes in the sensibility of the device after a {gamma}-rays accumulated dose up to 10kGy is also presented.

  20. Keratoacanthoma Dan Perawatannya

    OpenAIRE

    Indah Heriyanti

    2008-01-01

    Keratoacanthoma adalah suatu tumor jinak yang berasal dari jaringan epitel dan biasanya di jumpai pada permukaan kulit yang umumnya terjadi pada bagian kulit yang sering terkena sinar matahari dimana tumor ini dapat sembuh dengan spontan. Lesi ini biasanya berawal sebagai makula yang kecil yang berwarna merah dan kemudian menjadi papula yang kokoh dan bersisik pada permukaanya. Papul ini dengan cepat membesar selama 2 sampai 8 minggu. Pada awalnya berbentuk bulat atau oval,kokoh menonjol ...

  1. DEPRESI DAN GANGGUAN TIDUR

    Directory of Open Access Journals (Sweden)

    Wayan Eko Radityo

    2012-12-01

    Full Text Available Depresi merupakan gangguan mood berupa kesedihan yang intens, berlangsung dalamwaktu lama, dan mengganggu kehidupan normal yang insidennya semakin meningkatseiring dengan meningkatnya tekanan hidup. Tahun 2020, depresi diperkirakanmenempati urutan kedua penyakit di dunia. Gejala-gejala depresi terdiri dari gangguanemosi, gangguan kognitif, keluhan somatik, gangguan psikomotor, dan gangguanvegetatif. Salah satu gejala depresi yang muncul adalah gangguan tidur yang bisaberupa insomnia, bangun secara tiba-tiba, dan hipersomnia. Hal ini disebabkan olehgangguan neurotransmiter dan regulasi hormon. Selain sebagai gejala depresi, gangguantidur juga bisa merupakan penyebab depresi. Beberapa penelitian memberikanhubungan gangguan tidur dapat meningkatkan risiko depresi di kemudian hari.

  2. Problems of pricing fresh water obtained from a sea water desalination plant; Problemes de tarification de l'eau douce obtenue a partir d'une installation de dessalement d'eau de mer

    Energy Technology Data Exchange (ETDEWEB)

    Gaussens, J. [Commissariat a l' Energie Atomique, (France). Centre d' Etudes Nucleaires

    1967-07-01

    Integrating a double-purpose desalination and electricity generating plant into a water supply system alters the conditions in which the other water and electricity sources are used, as the peak and the base load water and electricity demands have to be met at the least cost. This paper attempts to show how the problem of determining optimal water supply structures can be approached, in definite cases, but against a global economic back-ground. It becomes necessary to define the competition between classical resources and desalination plants, as these plants introduce into optimum studies new factors due to the peculiar shape of their production functions. These new factors (fixed and proportional costs structures, flow availabilities) are studied in relation to the production functions in various management cases (private monopoly, public monopoly). (author) [French] L'intervention d'une installation egalement productrice d'energie electrique dans l'alimentation en eau d'une zone modifie les conditions d'utilisation des autres ressources en eau et en electricite, compte tenu de la necessite d'assurer les pointes et la base des diagrammes de demande d'eau et d'electricite au moindre cout. Cet expose se propose de montrer comment on peut approcher le probleme de la determination des structures optimales d'approvisionnement en eau pour des cas precis, mais dans un cadre economique global, II devient en effet necessaire de situer la competition: ressources classiques/installation de dessalement; ces dernieres introduisent, dans les etudes d'optimum, des elements nouveaux dus a la forme particuliere de leurs fonctions de production. On etudie ces elements nouveaux (structures des couts fixes et des couts proportionnels, disponibilite des debits) en liaison avec les fonctions de production dans divers cas de gestion (monopole prive, monopole public). (auteur)

  3. Active Oxidation of SiC

    Science.gov (United States)

    Jacobson, Nathan S.; Myers,Dwight L.; Harder, Bryan J.

    2011-01-01

    The high temperature oxidation of silicon carbide occurs in either a passive or active mode, depending on temperature and oxygen potential. Passive oxidation forms a protective oxide film which limits attack of the SiC:SiC(s) + 3/2 O2(g) = SiO2(s) + CO(g.) Active oxidation forms a volatile oxide and leads to extensive attack of the SiC: SiC(s) + O2(g) = SiO(g) + CO(g). The transition points and rates of active oxidation are a major issue. Previous studies are reviewed and the leading theories of passive/active transitions summarized. Comparisons are made to the active/passive transitions in pure Si, which are relatively well-understood. Critical questions remain about the difference between the active-to-passive transition and passive-to-active transition. For Si, Wagner [2] points out that the active-to-passive transition is governed by the criterion for a stable Si/SiO2 equilibria and the passive-to-active transition is governed by the decomposition of the SiO2 film. This suggests a significant oxygen potential difference between these two transitions and our experiments confirm this. For Si, the initial stages of active oxidation are characterized by the formation of SiO(g) and further oxidation to SiO2(s) as micron-sized rods, with a distinctive morphology. SiC shows significant differences. The active-to-passive and the passive-to-active transitions are close. The SiO2 rods only appear as the passive film breaks down. These differences are explained in terms of the reactions at the SiC/SiO2 interface. In order to understand the breakdown of the passive film, pre-oxidation experiments are conducted. These involve forming dense protective scales of 0.5, 1, and 2 microns and then subjecting the samples with these scales to a known active oxidation environment. Microstructural studies show that SiC/SiO2 interfacial reactions lead to a breakdown of the scale with a distinct morphology.

  4. Irradiation damage of SiC semiconductor device (I)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Yeon; Kim, Weon Ju

    2000-09-01

    This report reviewed the irradiation damage of SiC semiconductor devices and examined a irradiation behavior of SiC single crystal as a pre-examination for evaluation of irradiation behavior of SiC semiconductor devices. The SiC single was crystal irradiated by gamma-beam, N+ ion and electron beam. Annealing examinations of the irradiated specimens also were performed at 500 deg C. N-type 6H-SiC dopped with N+ ion was used and irradiation doses of gamma-beam, N+ion and electron beam were up to 200 Mrad, 1x10{sup 16} N{sup +} ions/cm{sup 2} and 3.6 x 10{sup 17} e/cm{sup 2} and 1.08 x 10{sup 18} e/cm{sup 2} , respectively. Irradiation damages were analyzed by the EPR method. Additionally, properties of SiC, information about commercial SiC single crystals and the list of web sites with related to the SiC device were described in the appendix.

  5. Compatibility of SiC and SiC Composites with Molten Lead

    Energy Technology Data Exchange (ETDEWEB)

    H Tunison

    2006-03-07

    The choice of structural material candidates to contain Lead at 1000 C are limited in number. Silicon carbide composites comprise one choice of possible containment materials. Short term screening studies (120 hours) were undertaken to study the behavior of Silicon Carbide, Silicon Nitride, elemental Silicon and various Silicon Carbide fiber composites focusing mainly on melt infiltrated composites. Isothermal experiments at 1000 C utilized graphite fixtures to contain the Lead and material specimens under a low oxygen partial pressure environment. The corrosion weight loss values (grams/cm{sup 2} Hr) obtained for each of the pure materials showed SiC (monolithic CVD or Hexoloy) to have the best materials compatibility with Lead at this temperature. Increased weight loss values were observed for pure Silicon Nitride and elemental Silicon. For the SiC fiber composite samples those prepared using a SiC matrix material performed better than Si{sub 3}N{sub 4} as a matrix material. Composites prepared using a silicon melt infiltration process showed larger corrosion weight loss values due to the solubility of silicon in lead at these temperatures. When excess silicon was removed from these composite samples the corrosion performance for these material improved. These screening studies were used to guide future long term exposure (both isothermal and non-isothermal) experiments and Silicon Carbide composite fabrication work.

  6. Detail study of SiC MOSFET switching characteristics

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig

    2014-01-01

    This paper makes detail study of the latest SiC MOSFETs switching characteristics in relation to gate driver maximum current, gate resistance, common source inductance and parasitic switching loop inductance. The switching performance of SiC MOSFETs in terms of turn on and turn off voltage...... and current are presented. Switching losses analysis is made according to the experiment results. The switching characteristics study and switching losses analysis could give some guidelines of gate driver IC and gate resistance selection, switching losses estimation and circuit design of SiC MOSFETs....

  7. Challenges in Switching SiC MOSFET without Ringing

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig

    2014-01-01

    Switching SiC MOSFET without ringing in high frequency applications is important for meeting the EMI (ElectroMagnetic Interference) standard. Achieving a clean switching waveform of SiC MOSFET without additional components is becoming a challenge. In this paper, the switching oscillation mechanism...... is analysed in detail. According to the analysis, the optimal circuit design to minimize the parasitic parametric is introduced for a clean switching waveform. Experiment results show the clean switching waveform of SiC MOSFET. Guidelines are established for circuit design....

  8. Bubble formation in oxide scales on SiC

    Science.gov (United States)

    Mieskowski, D. M.; Mitchell, T. E.; Heuer, A. H.

    1984-01-01

    The oxidation of alpha-SiC single crystals and sintered alphaand beta-SiC polycrystals has been investigated at elevated temperatures. Bubble formation is commonly observed in oxide scales on polycrystalline SiC, but is rarely found on single-crystal scales; bubbles result from the preferential oxidation of C inclusions, which are abundant in SiC polycrystals. The absence of bubbles on single crystals, in fact, implies that diffusion of the gaseous species formed on oxidation, CO (or possibly SiO), controls the rate of oxidation of SiC.

  9. SiC MOSFETs based split output half bridge inverter

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig; Beczkowski, Szymon

    2014-01-01

    Body diode of SiC MOSFETs has a relatively high forward voltage drop and still experiences reverse recovery phenomenon. Half bridge with split output aims to decouple both the body diode and junction capacitance of SiC MOSFETs, therefore achieving a reduced switching loss in a bridge configuration....... This paper makes the current commutation mechanism and efficiency analysis of half bridge with split output based on SiC MOSFETs. Current commutation process analysis is illustrated together with LTspice simulation and afterwards, verified by the experimental results of a double pulse test circuit with split...

  10. Bubble formation in oxide scales on SiC

    Science.gov (United States)

    Mieskowski, D. M.; Mitchell, T. E.; Heuer, A. H.

    1984-01-01

    The oxidation of alpha-SiC single crystals and sintered alphaand beta-SiC polycrystals has been investigated at elevated temperatures. Bubble formation is commonly observed in oxide scales on polycrystalline SiC, but is rarely found on single-crystal scales; bubbles result from the preferential oxidation of C inclusions, which are abundant in SiC polycrystals. The absence of bubbles on single crystals, in fact, implies that diffusion of the gaseous species formed on oxidation, CO (or possibly SiO), controls the rate of oxidation of SiC.

  11. L'optimisation du processus d'administration des achats à SIG: comment préparer les unités de l'entreprise aux changements d'organisation et comment mesurer les améliorations obtenues?

    OpenAIRE

    Laurent CRETEGNY; Arrayet, Pierre

    2009-01-01

    Au début de l’année 2007, SIG a lancé un projet d’amélioration du processus transverse d’administration des achats (projet ADAGE). Les objectifs principaux qui ont été fixés sont la réduction des coûts de gestion et la diminution des délais de paiement des fournisseurs. Une analyse des disfonctionnements du processus a conduit à proposer 28 pistes d’améliorations dont les effets toucheront principalement les 238 demandeurs SAP (émetteurs des commandes) répartis dans toute l’entreprise. Elles ...

  12. SiC Avalanche Photodiodes and Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aymont Technology, Inc. (Aymont) will demonstrate the feasibility of SiC p-i-n avalanche photodiodes (APD) arrays. Aymont will demonstrate 4 x 4 arrays of 2 mm2 APDs...

  13. Microwave joining of SiC ceramics and composites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Silberglitt, R.; Tian, Y.L. [FM Technologies, Inc., Fairfax, VA (United States); Katz, J.D. [Los Alamos National Lab., NM (United States)

    1997-04-01

    Potential applications of SiC include components for advanced turbine engines, tube assemblies for radiant burners and petrochemical processing and heat exchangers for high efficiency electric power generation systems. Reliable methods for joining SiC are required in order to cost-effectively fabricate components for these applications from commercially available shapes and sizes. This manuscript reports the results of microwave joining experiments performed using two different types of SiC materials. The first were on reaction bonded SiC, and produced joints with fracture toughness equal to or greater than that of the base material over an extended range of joining temperatures. The second were on continuous fiber-reinforced SiC/SiC composite materials, which were successfully joined with a commercial active brazing alloy, as well as by using a polymer precursor.

  14. An Extension of SIC Predictions to the Wiener Coactive Model.

    Science.gov (United States)

    Houpt, Joseph W; Townsend, James T

    2011-06-01

    The survivor interaction contrasts (SIC) is a powerful measure for distinguishing among candidate models of human information processing. One class of models to which SIC analysis can apply are the coactive, or channel summation, models of human information processing. In general, parametric forms of coactive models assume that responses are made based on the first passage time across a fixed threshold of a sum of stochastic processes. Previous work has shown that that the SIC for a coactive model based on the sum of Poisson processes has a distinctive down-up-down form, with an early negative region that is smaller than the later positive region. In this note, we demonstrate that a coactive process based on the sum of two Wiener processes has the same SIC form.

  15. DC characteristics of the SiC Schottky diodes

    National Research Council Canada - National Science Library

    W Janke; A Hapka; M Oleksy

    2011-01-01

      DC characteristics of the SiC Schottky diodes The isothermal and non-isothermal characteristics of silicon carbide Schottky diodes in the wide range of currents and ambient temperatures are investigated in this paper...

  16. Enregistrement Optique dans des Couches Minces de Tellure Modifiees Par Implantation

    Science.gov (United States)

    Beauvais, Jacques

    Cette etude des proprietes d'enregistrement optique des couches minces de tellure a porte sur l'introduction d'impuretes dans le materiau par le mecanisme d'implantation ionique. Les travaux ont revele des caracteristiques importantes de l'influence de l'implantation d'ions de gaz rares (He ^{+} et Ne^ {+}) et d'ions de Li^{+ } sur les proprietes du milieu enregistreur. Lors de l'implantation des ions de gaz rares, une dose implantee critique et une energie ionique critique ont ete identifiees demarquant des discontinuites dans le comportement des seuils d'ecriture, des coefficients optiques et de la structure cristalline des couches minces de tellure. Ces valeurs critiques dependent fortement des conditions de preparation du materiau et de l'espece d'ions implantee. De plus, l'implantation d'ions Li^{+} a demontre qu'une amelioration importante de la stabilite a long terme des couches minces peut etre obtenue par le processus d'implantation.

  17. Synthesis of micro-sized interconnected Si-C composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Donghai; Yi, Ran; Dai, Fang

    2016-02-23

    Embodiments provide a method of producing micro-sized Si--C composites or doped Si--C and Si alloy-C with interconnected nanoscle Si and C building blocks through converting commercially available SiO.sub.x (0

  18. Avalanche robustness of SiC Schottky diode

    OpenAIRE

    Dchar, Ilyas; Buttay, Cyril; Morel, Hervé

    2016-01-01

    International audience; Reliability is one of the key issues for the application of Silicon carbide (SiC) diode in high power conversion systems. For instance, in high voltage direct current (HVDC) converters, the devices can be submitted to high voltage transients which yield to avalanche. This paper presents the experimental evaluation of SiC diodes submitted to avalanche, and shows that the energy dissipation in the device can increase quickly and will not be uniformly distributed across t...

  19. Electrical Characterization of Defects in SiC Schottky Barriers

    Science.gov (United States)

    Schnabel, C. M.; Tabib-Azar, M.; Raffaelle, R. P.; Su, H. B.; Dudley, M.; Neudeck, P. G.; Bailey, S.

    2005-01-01

    We have been investigating the effect of screw dislocation and other structural defects on the electrical properties of SiC. SiC is a wide-bandgap semiconductor that is currently received much attention due to its favorable high temperature behavior and high electric field breakdown strength. Unfortunately, the current state-of-the-art crystal growth and device processing methods produce material with high defect densities, resulting in a limited commercial viability

  20. Preparation of SiC Fiber Reinforced Nickel Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    Lu Zhang; Nanlin Shi; Jun Gong; Chao Sunt

    2012-01-01

    A method of preparing continuous(Al+Al2O3)-coated SiC fiber reinforced nickel matrix composite was presented,in which the diffusion between SiC fiber and nickel matrix could be prevented.Magnetron sputtering is used to deposit Ni coating on the surface of the(Al+Al2O3)-coated SiC fiber in preparation of the precursor wires.It is shown that the deposited Ni coating combines well with the(Al+Al2O3) coating and has little negative effect on the tensile strength of(Al+Al2O3)-coated SiC fiber.Solid-state diffusion bonding process is employed to prepare the(Al+Al2O3)-coated SiC fiber reinforced nickel matrix with 37% fibers in volume.The solid-state diffusion bonding process is optimized and the optimum parameters are temperature of 870,pressure of 50 MPa and holding time of 2 h.Under this condition,the precursor wires can diffuse well,composite of full density can be formed and the(Al+Al2O3) coating is effective to restrict the reaction between SiC fiber and nickel matrix.

  1. Continuous SiC fiber, CVI SiC matrix composites for nuclear applications: Properties and irradiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Yutai, E-mail: katohy@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Ozawa, Kazumi; Shih, Chunghao; Nozawa, Takashi [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Shinavski, Robert J. [Hyper-Therm High Temperature Composites, Inc., Huntington Beach, CA (United States); Hasegawa, Akira [Tohoku University, Sendai, Miyagi-ken (Japan); Snead, Lance L. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2014-05-01

    Silicon carbide (SiC) continuous fiber-reinforced, SiC-matrix composites (SiC/SiC composites) are industrially available materials that are promising for applications in nuclear environments. The SiC/SiC composites consisting of near-stoichiometric SiC fibers, stoichiometric and fully crystalline SiC matrices, and the pyrocarbon (PyC) or multilayered PyC/SiC interphase between the fiber and the matrix are considered particularly resistant to very high radiation environments. This paper provides a summary compilation of the properties of these composites, specifically those with the chemically vapor-infiltrated (CVI) SiC matrices, including newly obtained results. The properties discussed are both in unirradiated condition and after neutron irradiation to intermediate fluence levels (most data are for <∼10 displacement per atom) at 300–1300 °C.

  2. The impact resistance of SiC and other mechanical properties of SiC and Si3N4

    Science.gov (United States)

    Bradt, R. C.

    1984-01-01

    Studies focused on the impact and mechanical behavior of SiC and Si3N4 at high temperatures are summarized. Instrumented Charpy impact testing is analyzed by a compliance method and related to strength; slow crack growth is related to processing, and creep is discussed. The transient nature of flaw populations during oxidation under load is emphasized for both SiC and Si3N4.

  3. Dan Performer Mei Lanfang

    DEFF Research Database (Denmark)

    Risum, Janne

    2010-01-01

    The convention of performing female characters (dan characters) in Beijing opera, as practised by its most prominent male performer of female characters Mei Lanfang, and its and his cultural context and aesthetic aim...

  4. Liever kraanwater dan bronwater

    NARCIS (Netherlands)

    Kole, A.P.W.

    2011-01-01

    Een test in het Restaurant van de Toekomst van de invloed van CO2-labels op het aankoopgedrag van consumenten, heeft nog geen duidelijk beeld opgeleverd. Wel pakten mensen vaker kraanwater dan bronwater.

  5. Proprietes optiques dans l'infrarouge lointain et de transport electrique de systemes electroniques a basse dimensionalite

    Science.gov (United States)

    Lefebvre, Jacques

    Cette these presente une etude experimentale de deux systemes ayant des proprietes physiques particulieres decoulant de leur caractere anisotrope. Le premier systeme est un conducteur organique quasi-unidimensionnel, le sel de Bechgaard (TMTSF)sb2ClOsb4. Le second est un systeme mesoscopique base sur une heterostructure a base de GaAs/Alsb{x}Gasb{1-x}As pour lequel la dimensionalite peut etre variee continuement entre deux et un. En dimension un, ce systeme porte le nom de fil quantique. Pour le sel de Bechgaard (TMTSF)sb2ClOsb4, une mesure de la photoconductivite dans l'infrarouge lointain a permis d'identifier une resonance dans la phase onde de densite de spin sous champ magnetique (ou ODSIC). Cette resonance, visible dans la gamme de longueurs d'onde entre 410 et 599 mum, se deplace vers les forts champs magnetiques avec l'augmentation de l'energie du photon. Malgre qu'elle s'apparente a une resonance cyclotron, un calcul theorique du coefficient d'absorption a montre qu'elle est intimement liee a la phase ODSIC et que son energie est donnee par sqrt{4deltasbsp{N}{2}+omegasbsp{c}{2}} avec deltasb{N}, l'amplitude de la bande interdite ODSIC au niveau de Fermi et omegasb{c}, l'energie cyclotron. Le gaz d'electrons dans une heterostructure a base de GaAs/Alsb{x}Gasb{1-x}As a ete etudie dans les regimes dimensionnels entre deux et un (de 2D a quasi-1D en passant par quasi-2D). En combinant des mesures de transport electrique a des mesures de transmission optique dans l'infrarouge lointain obtenues quasi-simultanement sur un meme echantillon, plusieurs conclusions emergent. Entre autres, trois regimes de modulation sont identifies et a leurs frontieres, des signes distinctifs apparaissent autant dans les mesures de transport que dans les mesures de la transmission optique. Une analyse globale permet de degager une vue coherente des modes collectifs dans les differents regimes dimensionnels.

  6. /SiC Composite to Titanium Alloy

    Science.gov (United States)

    Hernandez, X.; Jiménez, C.; Mergia, K.; Yialouris, P.; Messoloras, S.; Liedtke, V.; Wilhelmi, C.; Barcena, J.

    2014-08-01

    In view of aerospace applications, an innovative structure for joining a Ti alloy to carbon fiber reinforced silicon carbide has been developed. This is based on the perforation of the CMC material, and this procedure results in six-fold increase of the shear strength of the joint compared to the unprocessed CMC. The joint is manufactured using the active brazing technique and TiCuAg as filler metal. Sound joints without defects are produced and excellent wetting of both the composite ceramic and the metal is observed. The mechanical shear tests show that failure occurs always within the ceramic material and not at the joint. At the CMC/filler, Ti from the filler metal interacts with the SiC matrix to form carbides and silicides. In the middle of the filler region depletion of Ti and formation of Ag and Cu rich regions are observed. At the filler/Ti alloy interface, a layered structure of the filler and Ti alloy metallic elements is formed. For the perforation to have a significant effect on the improvement of the shear strength of the joint appropriate geometry is required.

  7. Makna Dan Ideologi Punk

    OpenAIRE

    Daniar Wikan Setyanto

    2015-01-01

    Punk Sebagai sebuah subkultur telah diadaptasi oleh para remaja Indonesia bukan hanya sebagai semangat bermusik, namun merambah sebagai ideologi dan gaya hidup. Punk merupakan warisan budaya dari barat yang awalnya bergerak pada bidang musik, namun lambat lain punk telah menjadi sebuah identitas global yang mewakili para remaja radikal yang memiliki visi anti kemapanan dan anti pemerintah. Selain ideologinya yang kontroversi, punk mempengaruhi dinamika fashion di dunia. Asesoris punk diadapta...

  8. Quels sont les enjeux d'une barrière de diffusion de carbure de titane entre le tungstène et le carbure de silicium, sur l'élaboration par dépôt chimique en phase vapeur, et sur les propriétés mécaniques du renfort filamentaire de SiC ?

    OpenAIRE

    Boiteau-Auvray, Sophie

    1997-01-01

    Les filaments de SiC sont obtenus par depot chimique en phase vapeur sur un substrat de W chauffe par effet Joule. Ces filaments peuvent etre utilises comme renforts dans des matrices d' alliage de titane. L' interposition d' une phase synthetique de TiC entre un substrat filamentaire de W et le depot de SiC a permis d' obtenir une stabilite thermochimique accrue du couple de diffusion. Les mecanismes conduisant a la protection chimique ont ete identifies. Une simulation numerique du depot de...

  9. SiC protective coating for photovoltaic retinal prosthesis

    Science.gov (United States)

    Lei, Xin; Kane, Sheryl; Cogan, Stuart; Lorach, Henri; Galambos, Ludwig; Huie, Philip; Mathieson, Keith; Kamins, Theodore; Harris, James; Palanker, Daniel

    2016-08-01

    Objective. To evaluate plasma-enhanced, chemically vapor deposited (PECVD) amorphous silicon carbide (α-SiC:H) as a protective coating for retinal prostheses and other implantable devices, and to study their failure mechanisms in vivo. Approach. Retinal prostheses were implanted in rats sub-retinally for up to 1 year. Degradation of implants was characterized by optical and scanning electron microscopy. Dissolution rates of SiC, SiN x and thermal SiO2 were measured in accelerated soaking tests in saline at 87 °C. Defects in SiC films were revealed and analyzed by selectively removing the materials underneath those defects. Main results. At 87 °C SiN x dissolved at 18.3 ± 0.3 nm d-1, while SiO2 grown at high temperature (1000 °C) dissolved at 0.104 ± 0.008 nm d-1. SiC films demonstrated the best stability, with no quantifiable change after 112 d. Defects in thin SiC films appeared primarily over complicated topography and rough surfaces. Significance. SiC coatings demonstrating no erosion in accelerated aging test for 112 d at 87 °C, equivalent to about 10 years in vivo, can offer effective protection of the implants. Photovoltaic retinal prostheses with PECVD SiC coatings exhibited effective protection from erosion during the 4 month follow-up in vivo. The optimal thickness of SiC layers is about 560 nm, as defined by anti-reflective properties and by sufficient coverage to eliminate defects.

  10. Thermal shock tests of $beta;-sic pellets prepared from laser synthesized nanoscale sic powders

    Science.gov (United States)

    Donato, A.; Borsella, E.; Botti, S.; Martelli, S.; Nannetti, C. A.; Mancini, M. R.; Morjan, I.

    1996-10-01

    Nanoscale SiC powders, produced by laser synthesis from gaseous precursors, have been successfully used to prepare sintered pellets. All the sintered samples showed the low temperature β-SiC structures and presented an enhanced thermal conductivity (> 20%) with respect to materials prepared from commercial powders. Samples hardness and toughness, comparable with commercial products, confirmed the good samples quality. The thermal shock tests have been performed by irradiating the pellets with a Nd-YAG pulsed laser (pulse duration and energy: 0.25 μs and 0.18 J or 0.4 ms and 0.65 J). The laser fluence (power density) was increased by reducing the spot size, up to the appearance of a visible surface damage. The threshold values for the structural damage were quantified using a heat flux parameter φ abs√ tp. The measured threshold value rose from ca. 20 MW/m 2 √s for the best materials prepared from commercial SiC powders to ca. 24 MW/m 2√s for the newly developed β-SiC.

  11. LES VARIANTES LEXICALES POUR LE MOT ESPADRILLES AU PARANÁ ET DANS LA RÉGION NORD-EST DU BRÉSIL: UNE ETUDE ETHNOLINGUISTIQUE

    Directory of Open Access Journals (Sweden)

    Maranúbia Pereira Barbosa Doiron

    2014-03-01

    Full Text Available : Cette étude concerne les variantes lexicales pour le mot espadrilles dans l’Etat du Paraná et dans la région Nord-Est du Brésil, sous un regard ethnolinguistique. Le corpus est composé par les donnés obtenues à partir de la question numéro 276 du Questionnaire Semantique-Lexical de l’Atlas Linguistique du Paraná (ALPR, dont l’auteur est le professeur Vanderci de Andrade Aguilera (1994, de l’Université de l’Etat de Londrina, autant que les variantes lexicales pour le mot espadrilles trouvées dans deux ouvrages littéraires d’auteurs originaires du Nord-Est du Brésil – Fogo Morto, de José Lins do Rego (2009 et Vidas Secas, de Graciliano Ramos (1969. Dans ces livres, les espadrilles jouent un rôle fondamental, tout en reflétant son importance dans le vestiaire de cette région, du moins jusqu’à moitié du XXème siècle. On rechercha des éventuelles ressemblances ou différences existentes entre les variantes lexicales de la chaussure mentionnée par les informateurs “paranaenses” et le modèle cité dans les ouvrages des écrivains Rego et Ramos. Dans les deuxs sources – la linguistique et la littéraire – on privilégia l’analyse semantique des unités lexicales et le contexte dans lequel elles ont été enregistrées. L’étude démontra que l’unité lexicale espadrilles et ses variantes phonétiques similaires dans les deux corpora, aussi que les variantes lexicales populaires présentes dans l’Atlas Linguistique du Paraná (ALPR. En dépit des simitudes l’esthétique et la fonction des espadrilles ne sont pas les mêmes dans les localitées concernées.

  12. LES VARIANTES LEXICALES POUR LE MOT ESPADRILLES AU PARANÁ ET DANS LA RÉGION NORD-EST DU BRÉSIL: UNE ETUDE ETHNOLINGUISTIQUE

    Directory of Open Access Journals (Sweden)

    Vanderci de Andrade AGUILERA

    2013-12-01

    Full Text Available Cette étude concerne les variantes lexicales pour le mot espadrilles dans l’Etat du Paraná et dans la région Nord-Est du Brésil, sous un regard ethnolinguistique. Le corpus est composé par les donnés obtenues à partir de la question numéro 276 du Questionnaire Semantique-Lexical de l’Atlas Linguistique du Paraná (ALPR, dont l’auteur est le professeur Vanderci de Andrade Aguilera (1994, de l’Université de l’Etat de Londrina, autant que les variantes lexicales pour le mot espadrilles trouvées dans deux ouvrages littéraires d’auteurs originaires du Nord-Est du Brésil – Fogo Morto, de José Lins do Rego (2009 et Vidas Secas, de Graciliano Ramos (1969. Dans ces livres, les espadrilles jouent un rôle fondamental, tout en reflétant son importance dans le vestiaire de cette région, du moins jusqu’à moitié du XXème siècle. On rechercha des éventuelles ressemblances ou différences existentes entre les variantes lexicales de la chaussure mentionnée par les informateurs “paranaenses” et le modèle cité dans les ouvrages des écrivains Rego et Ramos. Dans les deuxs sources – la linguistique et la littéraire – on privilégia l’analyse semantique des unités lexicales et le contexte dans lequel elles ont été enregistrées. L’étude démontra que l’unité lexicale espadrilles et ses variantes phonétiques similaires dans les deux corpora, aussi que les variantes lexicales populaires présentes dans l’Atlas Linguistique du Paraná (ALPR. En dépit des simitudes l’esthétique et la fonction des espadrilles ne sont pas les mêmes dans les localitées concernées.

  13. X-ray fluorescence microtomography of SiC shells

    Energy Technology Data Exchange (ETDEWEB)

    Ice, G.E.; Chung, J.S. [Oak Ridge National Lab., TN (United States); Nagedolfeizi, M. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    TRISCO coated fuel particles contain a small kernel of nuclear fuel encapsulated by alternating layers of C and SiC. The TRISCO coated fuel particle is used in an advanced fuel designed for passive containment of the radioactive isotopes. The SiC layer provides the primary barrier for radioactive elements in the kernel. The effectiveness of this barrier layer under adverse conditions is critical to containment. The authors have begun the study of SiC shells from TRISCO fuel. They are using the fluorescent microprobe beamline 10.3.1. The shells under evaluation include some which have been cycled through a simulated core melt-down. The C buffer layers and nuclear kernels of the coated fuel have been removed by laser drilling through the SiC and then exposing the particle to acid. Elements of interest include Ru, Sb, Cs, Ce and Eu. The radial distribution of these elements in the SiC shells can be attributed to diffusion of elements in the kernel during the melt-down. Other elements in the shells originate during the fabrication of the TRISCO particles.

  14. Hysteresis in the Active Oxidation of SiC

    Science.gov (United States)

    Jacobson, Nathan S.; Harder, Bryan J.; Myers, Dwight L.

    2011-01-01

    Si and SiC show both passive oxidation behavior where a protective film of SiO2 forms and active oxidation behavior where a volatile suboxide SiO(g) forms. The active-to-passive and passive-to-active oxidation transitions are explored for both Si and SiC. Si shows a dramatic difference between the P(O2) for the two transitions of 10-4 bar. The active-to-passive transition is controlled by the condition for SiO2/Si equilibrium and the passive-to-active transition is controlled by the decomposition of SiO2. In the case of SiC, the P(O2) for these transitions are much closer. The active-to-passive transition appears to be controlled by the condition for SiO2/SiC equilibrium. The passive-to-active transition appears to be controlled by the interfacial reaction of SiC and SiO2 and subsequent generation of gases at the interface which leads to scale breakdown.

  15. TRISO coated fuel particles with enhanced SiC properties

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Honorato, E.; Tan, J.; Meadows, P.J. [Materials Science Centre, School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS (United Kingdom); Marsh, G. [Nexia Solutions Ltd., Spingfields, PR4 0XJ (United Kingdom); Xiao, P., E-mail: ping.xiao@manchester.ac.u [Materials Science Centre, School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS (United Kingdom)

    2009-07-15

    The silicon carbide (SiC) layer used for the formation of TRISO coated fuel particles is normally produced at 1500-1650 deg. C via fluidized bed chemical vapor deposition from methyltrichlorosilane in a hydrogen environment. In this work, we show the deposition of SiC coatings with uniform grain size throughout the coating thickness, as opposed to standard coatings which have larger grain sizes in the outer sections of the coating. Furthermore, the use of argon as the fluidizing gas and propylene as a carbon precursor, in addition to hydrogen and methyltrichlorosilane, allowed the deposition of stoichiometric SiC coatings with refined microstructure at 1400 and 1300 deg. C. The deposition of SiC at lower deposition temperatures was also advantageous since the reduced heat treatment was not detrimental to the properties of the inner pyrolytic carbon which generally occurs when SiC is deposited at 1500 deg. C. The use of a chemical vapor deposition coater with four spouts allowed the deposition of uniform and spherical coatings.

  16. Modelisation de la synthese reactive de poudres ultrafines dans un reacteur a plasma thermique

    Science.gov (United States)

    Desilets, Martin

    La presente these s'inscrit dans le cadre de la modelisation mathematique des ecoulements a plasmas thermiques inertes et reactifs. Elle vise plus precisement a combler les lacunes des modeles existants en portant une attention particuliere aux phenomenes de transport multicomposant et a la prediction des transformations chimiques. Pour repondre a ces attentes et ainsi poursuivre le developpement dans ce domaine, un modele global a ete developpe. Il combine la resolution d'equations conservatives pour la masse, l'energie et le momentum. La generation d'un plasma inductif (h.f ) y est traitee au moyen d'equations representant les champs electromagnetiques. La nucleation et la croissance de poudres ultrafines sont incluses dans le modele via l'analyse des principaux moments de la distribution des tailles de particules. Enfin, tous les phenomenes physico-chimiques d'importance dans un milieu comme les plasmas thermiques, de meme que lem interactions, sont consideres. Le modele est applique ici a l'analyse de trois problematiques differentes et complementaires. La premiere concerne l'etude du melange gazeux d'un jet froid (He, N 2 ou O2), injecte au coeur d'une decharge d'argon/hydrogene ou d'argon/oxygene. La comparaison des predictions du modele avec des mesures experimentales obtenues par une sonde enthalpique permet une validation partielle de ce dernier. La deuxieme problematique a trait a l'etude numerique de la pyrolyse du methane en reacteur a plasma h.f. Elle met en evidence les difficultes de convergence de la methode numerique lorsque appliquee a la resolution d'ecoulements reactifs a haute temperature. Finalement, le dernier sujet aborde dans cette these, soit l'analyse systematique des principales conditions d'operation d'un reacteur h.f utilise pour la synthese reactive de poudres ultrafines de silicium, engage tous les elements theoriques du modele. Il implique en effet la decomposition thermique d'un precurseur gazeux, le tetrachlorure de silicium, la

  17. Liens entre symétries et étirements de routages dans les réseaux d'interconnexions de centres de données

    OpenAIRE

    Coudert, David; Ducoffe, Guillaume

    2016-01-01

    International audience; Nous démontrons l'influence de propriétés des réseaux d'interconnexion de centres de données sur l'étirement obtenu pour des routages dits "géométriques". Ces routages reposent sur un plongement des sommets du graphe dans un espace métrique "simple" tel que le plan Hyperbolique. Les réseaux d'interconnexions des centres de données sont généralement conçus pour favoriser les symétries, celles-ci permettant de minimiser la congestion et à chaque entité d'exécuter le même...

  18. Ecoulement de gaz dans un long micro-canal : comparaison des modèles continu et cinétique

    OpenAIRE

    De Izarra, Léonard; Trouette, Benoît; Rouet, Jean-Louis; Izrar, Boujema

    2013-01-01

    National audience; Les écoulements de gaz dans des micro ou nano conduites mettent en jeu des effets de raréfaction et de compressibilité. Différents régimes d'écoulement (hydrodynamique, de glissement ou transitionnel) sont alors susceptibles de cohabiter et il est nécessaire d'utiliser une approche et des méthodes numériques adaptées. Les solutions obtenues par une méthode de résolution de l'équation de Boltzmann-BGK sont comparées aux solutions des équations de Navier-Stokes compressibles ...

  19. INOVASI DAN STRATEGI PENCAPAIANNYA

    Directory of Open Access Journals (Sweden)

    Liem Ferryanto

    2009-01-01

    Full Text Available Innovation is the way of life of any institution to profitably sustain its life. It starts with empathy, the ability to reach outside of ourselves and walk in someone else’s shoes, and optimal implementation of the newly advanced technology. Innovation shows its results through continuously hard working efforts known as "10 Thousand Hours Rule". As world uncertainty creates complexity we, instead of predicting, should therefore anticipate the future by creating and managing real options on contingent projects or elements of alternative optimal strategies. This should reflect into our portfolio strategy. Abstract in Bahasa Indonesia: Inovasi merupakan darah bagi suatu institusi untuk bisa hidup berkelanjutan serta menguntungkan. Inovasi berupa penemuan baru secara sistematis yang berawal dari empati, kemampuan untuk melihat dunia melalui mata orang lain, dan pemanfaatan secara optimal kemajuan teknologi yang ada. Inovasi baru menghasilkan buahnya melalui kerja keras, yaitu dengan mengikuti “Aturan 10 Ribu Jam” secara berkesinambungan. Ketidakpastian, interaksi, keterbatasan dan degradasi menciptakan kompleksitas tentang kebutuhan dan solusi di masa depan. Oleh sebab itu daripada meramalkan risiko yang bakal terjadi, kita sebaiknya memasang strategi berupa skenario untuk mereduksi akibat dari risiko masa depan yang tidak kita mengerti. Skenario ini dapat diperoleh lewat penciptaan dan penanganan beberapa pilihan nyata atas semua proyek antisipatif yang ada. Kata kunci: Inovasi, ketidakpastian dan kompleksitas, aturan 10 ribu jam, paradoks strategi, peta jalan, empati, kerja berkesinambungan.

  20. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Thermal and Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Alvine, Kyle J.; Roosendaal, Timothy J.; Shin, Yongsoon; Nguyen, Ba Nghiep; Borlaug, Brennan A.; Jiang, Weilin

    2014-04-01

    SiC-polymers (pure polycarbosilane and polycarbosilane filled with SiC-particles) are being combined with Si and TiC powders to create a new class of polymer-derived ceramics for consideration as advanced nuclear materials in a variety of applications. Compared to pure SiC these materials have increased fracture toughness with only slightly reduced thermal conductivity. Future work with carbon nanotube (CNT) mats will be introduced with the potential to increase the thermal conductivity and the fracture toughness. At present, this report documents the fabrication of a new class of monolithic polymer derived ceramics, SiC + SiC/Ti3SiC2 dual phase materials. The fracture toughness of the dual phase material was measured to be significantly greater than Hexoloy SiC using indentation fracture toughness testing. However, thermal conductivity of the dual phase material was reduced compared to Hexoloy SiC, but was still appreciable, with conductivities in the range of 40 to 60 W/(m K). This report includes synthesis details, optical and scanning electron microscopy images, compositional data, fracture toughness, and thermal conductivity data.

  1. Structural Properties of Liquid SiC during Rapid Solidification

    Directory of Open Access Journals (Sweden)

    WanJun Yan

    2013-01-01

    Full Text Available The rapid solidification of liquid silicon carbide (SiC is studied by molecular dynamic simulation using the Tersoff potential. The structural properties of liquid and amorphous SiC are analyzed by the radial distribution function, angular distribution function, coordination number, and visualization technology. Results show that both heteronuclear and homonuclear bonds exist and no atomic segregation occurs during solidification. The bond angles of silicon and carbon atoms are distributed at around 109° and 120°, respectively, and the average coordination number is <4. Threefold carbon atoms and fourfold silicon atoms are linked together by six typical structures and ultimately form a random network of amorphous structure. The simulated results help understand the structural properties of liquid and amorphous SiC, as well as other similar semiconductor alloys.

  2. Advanced SiC composites for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Snead, L.L.; Schwarz, O.J. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    This is a short review of the motivation for and progress in the development of ceramic matrix composites for fusion. Chemically vapor infiltrated silicon carbide (SiC) composites have been fabricated from continuous fibers of either SiC or graphite and tested for strength and thermal conductivity. Of significance is the the Hi-Nicalon{trademark} SiC based fiber composite has superior unirradiated properties as compared to the standard Nicalon grade. Based on previous results on the stability of the Hi-Nicalon fiber, this system should prove more resistant to neutron irradiation. A graphite fiber composite has been fabricated with very good mechnical properties and thermal conductivity an order of magnitude higher than typical SiC/SiC composites.

  3. Thermochemistry and growth mechanism of SiC nanowires

    Science.gov (United States)

    Chen, Jianjun; Ding, Lijuan; Xin, Lipeng; Zeng, Fan; Chen, Jun

    2017-09-01

    The chemical reaction thermodynamics and a novel two-stage growth mechanism of SiC nanowires synthesized by carbothermal reduction reactions were investigated based on the Si-C-O systems over a wide temperature range (1050 ≤ T ≤ 2000 K). The carbothermal reduction reaction process involves the fast formation of gaseous SiO and CO crucial intermediates, and the further carbon reduction of SiO to SiC. The relationship between the free energy changes and temperature at different pressures was also discussed. Some fundamental data in the work can help to analyze the thermochemistry of the carbothermal reduction reaction in the Si-C-O system, which is beneficial to optimize the temperature, pressure and the input precursors for controlling the SiC nanowire growth.

  4. PENGELOLAAN PENELITIAN DAN PENGEMBANGAN KESEHATAN DI THAILAND, MYANMAR, DAN INDIA

    Directory of Open Access Journals (Sweden)

    Anorital, SKM Anorital, SKM

    2012-09-01

    Full Text Available Dalam bulan Januari 1991 yang lalu, Sdr. Anorital, SKM (Ka. Subbag. Pengumpulan dan PengolahanData Badan Litbangkes dan H. Syafwani Mirin, SKM (Ka. Bag. Keuangan Badan Litbangkes memperoleh fellowship dari WHO untuk melakukan studi perbandingan ke institusi-institusi penelitian kesehatan di Thailand,Myanmar, dan India.Berikut di bawah ini tulisan bersangkutan yang menggambarkan secara garis besar pengelolaan penelitian dan pengembangan kesehatan pada masing-masing negara obyek studi. Semoga informasi yang terkandung pada tulisan ini dapat bermanfaat bagi pengembangan Badan Penelitian dan Pengembangan Kesehatan.

  5. Detection Simulation of SiC Semiconductor Detector

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In a high radiation environment, it has received attention as a material for detecting radiation (neutron). As the field of application of a SIC neutron detector, the semiconductor detector used in cosmic rays was proposed by Ruddy. Recently, X-ray and low-energy gamma ray spectrometry with SiC detectors has been reported. Its usability has recently been being proved in neutron dose surveillance in BNCT (Boron-Capture Neutron Therapy), thermal neutron detection in a waste drum, nuclear material surveillance, and fast neutron detection. In addition, in 2006, an experiment was actually performed by Natsume on spent nuclear fuel. SIC is suitable for radiation surveillance in a complex radiation field emitted from spent nuclear fuel and the pyropocess process. In the radiation field of spent nuclear fuel, neutrons and gamma rays are generated. In this research, the performance of a SiC detector made at KAERI was evaluated to obtain a discriminated neutron signal. First, using neutron ({sup 252}Cf), alpha ({sup 241}Am), and gamma ({sup 60}Co) sources, a SiC semi- conductor detector was tested. The energy spectrum in a complex radiation field was simulated using the MCNPX 2.5. Finally, the experimental results by Ruddy were compared with the simulation results. Research result, whether the SiC semiconductor detector operating or not was confirmed through the simulation according to the neutron, gamma. The simulation results were similar to those of Ruddy. A further study is underway to investigate the discriminated neutron signal of a complex radiation field.

  6. Packaging Technology for SiC High Temperature Electronics

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Meredith, Roger D.; Nakley, Leah M.; Beheim, Glenn M.; Hunter, Gary W.

    2017-01-01

    High-temperature environment operable sensors and electronics are required for long-term exploration of Venus and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500 C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors in relevant environments. This talk will discuss a ceramic packaging system developed for high temperature electronics, and related testing results of SiC integrated circuits at 500 C facilitated by this high temperature packaging system, including the most recent progress.

  7. Plasma synthesis and characterization of ultrafine SiC

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, G.J.; Phillips, D.S.; Taylor, T.N.

    1986-01-01

    Ultrafine SiC powders have been prepared by gas phase synthesis from silane and methane in an argon thermal rf-plasma. Bulk properties of the powders were determined by elemental analysis, x-ray diffractin, helium pycnometry, and BET surface area measurements. The near-surface composition and structure of the particles were examined by x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). In addition to free silicon and carbon particles in the powders, free carbon and various silicon/carbon/oxygen species were found on the surface of the SiC particles.

  8. Development of CVD Mullite Coatings for SiC Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, V.K.; Varadarajan, S.

    2000-03-15

    A process for depositing CVD mullite coatings on SiC fibers for enhanced oxidation and corrosion, and/or act as an interfacial protective barrier has been developed. Process optimization via systematic investigation of system parameters yielded uniform crystalline mullite coatings on SiC fibers. Structural characterization has allowed for tailoring of coating structure and therefore properties. High temperature oxidation/corrosion testing of the optimized coatings has shown that the coatings remain adherent and protective for extended periods. However, preliminary tests of coated fibers showed considerable degradation in tensile strength.

  9. On the band gap variation in SiC polytypes

    Energy Technology Data Exchange (ETDEWEB)

    Haeringen, W. van; Bobbert, P.A.; Backes, W.H. [Technische Univ. Eindhoven (Netherlands). Dept. of Physics

    1997-07-01

    Electronic band gaps of SiC polytypes are reproduced within an interface matching technique of electronic wave functions. Essential features resulting from this treatment are introduced in a one-dimensional model, leading to a transparent description of the electronic band gap variation among polytypes. It is discussed in what sense the polytypes of SiC are exceptional in showing a relatively strong band gap variation, contrary to e.g. polytypes of ZnS and hypothetical polytypes made up from Si, C or AlAs. (orig.) 36 refs.

  10. On the Band Gap Variation in SiC Polytypes

    Science.gov (United States)

    van Haeringen, W.; Bobbert, P. A.; Backes, W. H.

    1997-07-01

    Electronic band gaps of SiC polytypes are reproduced within an interface matching technique of electronic wave functions. Essential features resulting from this treatment are introduced in a one-dimensional model, leading to a transparent description of the electronic band gap variation among polytypes. It is discussed in what sense the polytypes of SiC are exceptional in showing a relatively strong band gap variation, contrary to e.g. polytypes of ZnS and hypothetical polytypes made up from Si, C or AlAs.

  11. DanRIS

    DEFF Research Database (Denmark)

    2009-01-01

    Windows 2000/XP/Vista platform computerprogram til DanRIS indberetning baseret på indskrivning af klienter på CPR, klientsforløb, faseforløb, ASI EuropASI composite score beregninger. Udgave: 2.1.0.5 Udgivelsesdato: 01-01-2009......Windows 2000/XP/Vista platform computerprogram til DanRIS indberetning baseret på indskrivning af klienter på CPR, klientsforløb, faseforløb, ASI EuropASI composite score beregninger. Udgave: 2.1.0.5 Udgivelsesdato: 01-01-2009...

  12. Makna Dan Ideologi Punk

    Directory of Open Access Journals (Sweden)

    Daniar Wikan Setyanto

    2015-08-01

    Full Text Available Punk Sebagai sebuah subkultur telah diadaptasi oleh para remaja Indonesia bukan hanya sebagai semangat bermusik, namun merambah sebagai ideologi dan gaya hidup. Punk merupakan warisan budaya dari barat yang awalnya bergerak pada bidang musik, namun lambat lain punk telah menjadi sebuah identitas global yang mewakili para remaja radikal yang memiliki visi anti kemapanan dan anti pemerintah. Selain ideologinya yang kontroversi, punk mempengaruhi dinamika fashion di dunia. Asesoris punk diadaptasi oleh budaya bopuler sebagai pernak-pernik fashion. Kini punk, telah menjadi bagian dari dunia fashion di seluruh dunia. Apa sebenarnya yang melatar belakangi munculnya Punk? bagaimana Punk bisa berkembang di Indonesia? Kata Kunci: punk, fashion, budaya populer

  13. First-principle Calculation of the Properties of Ti3SiC2

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The electronic and structural properties for Ti3SiC2 were studied using the first-principle calculation method. By using the calculated band structure and density of states, the high electrical conductivity of Ti3SiC2 are explained.The bonding character of Ti3SiC2 is analyzed in the map of charge density distribution.

  14. Influence of microstructure on hydrothermal corrosion of chemically vapor processed SiC composite tubes

    Science.gov (United States)

    Kim, Daejong; Lee, Ho Jung; Jang, Changheui; Lee, Hyeon-Geun; Park, Ji Yeon; Kim, Weon-Ju

    2017-08-01

    Multi-layered SiC composites consisting of monolithic SiC and a SiCf/SiC composite are one of the accident tolerant fuel cladding concepts in pressurized light water reactors. To evaluate the integrity of the SiC fuel cladding under normal operating conditions of a pressurized light water reactor, the hydrothermal corrosion behavior of multi-layered SiC composite tubes was investigated in the simulated primary water environment of a pressurized water reactor without neutron fluence. The results showed that SiC phases with good crystallinity such as Tyranno SA3 SiC fiber and monolithic SiC deposited at 1200 °C had good corrosion resistance. However, the SiC phase deposited at 1000 °C had less crystallinity and severely dissolved in water, particularly the amorphous SiC phase formed along grain boundaries. Dissolved hydrogen did not play a significant role in improving the hydrothermal corrosion resistance of the CVI-processed SiC phases containing amorphous SiC, resulting in a significant weight loss and reduction of hoop strength of the multi-layered SiC composite tubes after corrosion.

  15. MISKONSEPSI KONSEP ARCHAEBACTERIA DAN EUBACTERIA

    Directory of Open Access Journals (Sweden)

    Fina Nurul Khotimah

    2015-03-01

    Full Text Available Penelitian ini bertujuan untuk mengidentifikasi miskonsepsi siswa pada konsep Archaebacteria dan Eubacteria. Penelitian ini menggunakan metode survei dengan instrumen berupa pilihan ganda beralasan terbuka sebagai alat ukur. Unit analisis dalam penelitian adalah siswa MAN kelas X berjumlah 72 orang. Hasil analisis ditemukan ketidakpahaman pada konsep Archaebacteria dan Eubacteria (61% yang mendominasi kategori lainnya. Sedangkan kategori Paham konsep dan Miskonsepsi hanya sebesar 19% dan 20%. Miskonsepsi yang dialami siswa dari hasil diagnosa alasan terbuka menunjukkan lebih banyak miskonsepsi utuh dibandingkan dengan miskonsepsi sebagian. Miskonsepsi utuh teridentifikasi dengan siswa beranggapan bahwa bakteri lebih banyak menimbulkan kerugian daripada keuntungan bagi manusia dan lingkungan.

  16. Long SiC nanowires synthesized from off-gases of the polycarbosilane-derived SiC preparation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gong-Yi; Li, Xiao-Dong; Wang, Hao [National University of Defense Technology, State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, Changsha (China); Liu, Lin [Wuhan Mechanical Technology College, Wuhan (China)

    2010-02-15

    In this communication, we report on the attempt to make full use of the off-gases from polycarbosilane-derived SiC preparation, and we successfully synthesized long SiC nanowires in large areas with Fe(NO{sub 3}){sub 3} as catalyst. The nanowires have diameters of about 80-300 nm and lengths of millimeters, and they are identified as single crystals {beta}-SiC along the left angle 111 right angle direction. The VLS mechanism was employed to interpret the nanowire growth. (orig.)

  17. Performance Evaluation of Split Output Converters with SiC MOSFETs and SiC Schottky Diodes

    OpenAIRE

    Yan, Qingzeng; Yuan, Xibo; Geng, Yiwen; Charalambous, Apollo; Wu, Xioajie

    2017-01-01

    The adoption of silicon carbide (SiC) MOSFETS and SiC Schottky diodes in power converters promises a further improvement of the attainable power density and system efficiency, while it is restricted by several issues caused by the ultra-fast switching, such as phase-leg shoot-through (‘crosstalk’ effect), high turn-on losses, electromagnetic interference (EMI), etc. This paper presents a split output converter which can overcome the limitations of the standard two-level voltage source convert...

  18. Les Elements Legers: Diffusion dans les Enveloppes Stellaires et Implications Cosmologiques

    Science.gov (United States)

    Richer, Jacques

    1992-01-01

    Les observations des abondances des elements legers (Z premieres minutes de l'expansion de l'Univers. Nous tenons compte de la difference possible entre l'abondance primordiale de Li et les abondances observees dans les plus vieilles etoiles. Cette difference (un facteur 2, environ) est estimee en construisant des modeles evolutifs d'etoiles peu massives de Population II, incluant la sedimentation gravitationnelle du lithium et de l'helium. Ces modeles montrent egalement que les ages des vieux amas stellaires sont grandement surestimes lorsqu'ils sont determines a partir de modeles stellaires n'incluant pas l'effet de la diffusion de He. Nous calculons ensuite comment evoluent les abondances de Li et Be dans des etoiles plus massives et plus jeunes, de la pre-sequence principale ou de la ZAMS, jusqu'a l'epuisement de leur hydrogene central. Les modeles incluent la sedimentation simultanee de l'helium a travers l'enveloppe. Une approche hierarchique (evolution du coeur--evolution de l'enveloppe --tri des elements traces) est utilisee pour simuler efficacement le grand nombre d'etoiles necessaire pour la construction d'isochrones. Une attention particuliere est portee aux consequences de la sedimentation de He sur l'etendue des zones convectives, et sur la diffusion de Li et Be. Les forces radiatives agissant sur ces deux elements sont calculees en detail a partir des donnees atomiques. Les etoiles simulees correspondent approximativement aux types spectraux A, F, et AmFm. Les abondances de Li et Be observees dans les etoiles jeunes de ces types sont comparees a nos predictions dans le but d'identifier les conditions ou la diffusion peut etre le processus principal. ou un processus important controlant les abondances superficielles observees. La position et la profondeur du "trou du lithium" observe parmi les etoiles F des Hyades et d'autres amas jeunes, sont reproduites sans l'aide de parametres ajustables; cet accord n'est obtenu que si les recentes opacites OPAL

  19. Macapat dan Santiswara

    OpenAIRE

    Darusuprapta, Darusuprapta

    2013-01-01

    Dalam khazanah kebudayaan Indonesia, khusus Jawa, hidup berkembangan kesenian macapat yang disebut juga  macapatan, dan kesenian santiswara yang disebut pula santiswaran. Macapatan lebih mengutamakan pembacaan teks dengan dendangan tembang kemudian diikuti sarasehan atau diskusi yang membahas segala segi isi teks bacaannya, sedangkan santiswaran lebih mengutamakan alunan swara dengan dendangan tembang disertai iringan bunyi tabuh-tabuhan.

  20. DANS LE CONTEXTE IVOIRIEN

    African Journals Online (AJOL)

    LA RELATION "GENRE" ET SES IMPLICATIONS SOCIOLOGIQUES. DANS LE CONTEXTE IVOIRIEN ... de base et de la gestion des affaires publiques en milieu rural .... Les raisons économiques; du fait du faible pouvoir d'achat des parents face au ..... cause de rupture du contrat, toute femme a le droit de suspendre son.

  1. Akromegali Dan Gigantisme

    OpenAIRE

    Silvani, Melati; Pase, M. Aron; Syafril, Santi; Lindarto, Dharma; Solin, Steffie S

    2016-01-01

    Hormon pertumbuhan manusia (Growth Hormone/GH) merupakan peptida rantai tunggal yang terdiri dari 191 asam amino, yang diisolasi dari sel somatotrop pada kelenjar hipofisis anterior pada tahun 1956, dan pertama kali digunakan sebagai terapi untuk penatalaksanaan dwarfisme hipofisis pada tahun 1958. Dwarfisme hipofisis adalah bentuk klasik dari defisiensi hormon pertumbuhan pada anak-anak Melati Silvani

  2. Conducted EMI in Inverters with SiC Transistors

    NARCIS (Netherlands)

    Gong, X.

    2013-01-01

    Conducted EMI in Inverters with SiC Transistors Electromagnetic Interference (EMI) is the main side effect accompanied with the fast voltage and current switching transients in power electronics applications. Compliance of the Electromagnetic Compatibility (EMC) standard is prescribed for any power

  3. Conducted EMI in Inverters with SiC Transistors

    NARCIS (Netherlands)

    Gong, X.

    2013-01-01

    Conducted EMI in Inverters with SiC Transistors Electromagnetic Interference (EMI) is the main side effect accompanied with the fast voltage and current switching transients in power electronics applications. Compliance of the Electromagnetic Compatibility (EMC) standard is prescribed for any power

  4. -SiC nanocomposite coatings synthesized by co-electrodeposition

    Science.gov (United States)

    Masoudi, Mehran; Hashim, Mansor; Kamari, Halimah Mohamed

    2014-08-01

    In the present work, Ni-Al2O3, Ni-SiC and novel Ni-Al2O3-SiC metal matrix composite (MMC) coatings were electrodeposited onto pure copper samples using a modified Watt's nickel electroplating bath containing nano alumina and silicon carbide particles with an average particle size of 50 nm. The composition, crystalline structure and surface morphology of the deposits were characterized by X-ray diffractometry (XRD), energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscopy (FESEM). The results indicated that Ni-Al2O3-SiC hybrid composite films with an acceptable homogeneity and granular structure having 9.2 and 7.7 % vol. Al2O3 and SiC nanoparticles, respectively were developed successfully. The nanoparticles incorporated in the nickel layer effectively increased the micro hardness and wear resistance owing to dispersion and grain-refinement strengthening, changing the nickel matrix morphology as well as the texture and preferred grain growth direction from to the close-packed . The oxidation resistance of the Ni-Al2O3-SiC hybrid composite coatings was measured to be approximately 41 % greater than the unreinforced Ni deposit and almost 30 % better than the Ni-Al2O3 composite coatings.

  5. Photoluminescence origin of nanocrystalline SiC films

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-wen; LI Juan; LI Yan-hui; LI Chang-ling; ZHAO Yan-ping; ZHAO Jie; XU Jing-jun

    2005-01-01

    The nanocrystalline SiC films were prepared on Si (111) substrates by rf magnetron sputtering and then annealed at 800℃ and 1 000℃ for 30 minutes in a vacuum annealing system. The crystal structure and crystallization of as-annealed SiC films were determined by the Fourier transform infrared (FTIR) absorption spectra and the X-ray diffraction (XRD) analysis. Measurement of photoluminescence (PL) of the nanocrystalline SiC (nc-SiC) films shows that the blue light with 473 nm and 477 nm wavelengths emitted at room temperature and that the PL peak shifts to shorter wavelength side and the PL intensity becomes stronger as the annealing temperature decreases. The time-resolved spectrum of the PL at 477 nm exhibits a bi-exponential decay process with lifetimes of 600 ps and 5 ns and a characteristic of the direct band gap.The strong blue light emission with short PL lifetimes suggests that the quantum confinement effect of the SiC nanocrystals resulted in the radiative recombination of the direct optical transitions.

  6. Performance of bulk SiC radiation detectors

    CERN Document Server

    Cunningham, W; Lamb, G; Scott, J; Mathieson, K; Roy, P; Bates, R; Thornton, P; Smith, K M; Cusco, R; Glaser, M; Rahman, M

    2002-01-01

    SiC is a wide-gap material with excellent electrical and physical properties that may make it an important material for some future electronic devices. The most important possible applications of SiC are in hostile environments, such as in car/jet engines, within nuclear reactors, or in outer space. Another area where the material properties, most notably radiation hardness, would be valuable is in the inner tracking detectors of particle physics experiments. Here, we describe the performance of SiC diodes irradiated in the 24 GeV proton beam at CERN. Schottky measurements have been used to probe the irradiated material for changes in I-V characteristics. Other methods, borrowed from III-V research, used to study the irradiated surface include atomic force microscope scans and Raman spectroscopy. These have been used to observe the damage to the materials surface and internal lattice structure. We have also characterised the detection capabilities of bulk semi-insulating SiC for alpha radiation. By measuring ...

  7. Saturn V Stage I (S-IC) Overview

    Science.gov (United States)

    Interbartolo, Michael

    2009-01-01

    Objectives include: a) Become familiar with the Saturn V Stage I (S-IC) major structural components: Forward Skirt, Oxidizer Tank, Intertank, Fuel Tank, and Thrust Structure. b) Gain a general understanding of the Stage I subsystems: Fuel, Oxidizer, Instrumentation, Flight Control, Environmental Control, Electrical, Control Pressure, and Ordinance.

  8. Advanced Capacitor with SiC for High Temperature Applications

    Science.gov (United States)

    Tsao, B. H.; Ramalingam, M. L.; Bhattacharya, R. S.; Carr, Sandra Fries

    1994-07-01

    An advanced capacitor using SiC as the dielectric material has been developed for high temperature, high power, and high density electronic components for aircraft and aerospace application. The conventional capacitor consists of a large number of metallized polysulfone films that are arranged in parallel and enclosed in a sealed metal case. However, problems with electrical failure, thermal failure, and dielectric flow were experienced by Air Force suppliers for the component and subsystem for lack of suitable properties of the dielectric material. The high breakdown electrical field, high thermal conductivity, and high temperature operational resistance of SiC compared to similar properties of the conventional ceramic and polymer capacitor would make it a better choice for a high temperature, and high power capacitor. The quality of the SiC film was evaluated. The electrical parameters, such as the capacitance, dissipation factor, equivalent series resistance, and dielectric withstand voltage, were evaluated. The prototypical capacitors are currently being fabricated using SiC film.

  9. Fission-product SiC reaction in HTGR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, F.

    1981-07-13

    The primary barrier to release of fission product from any of the fuel types into the primary circuit of the HTGR are the coatings on the fuel particles. Both pyrolytic carbon and silicon carbide coatings are very effective in retaining fission gases under normal operating conditions. One of the possible performance limitations which has been observed in irradiation tests of TRISO fuel is chemical interaction of the SiC layer with fission products. This reaction reduces the thickness of the SiC layer in TRISO particles and can lead to release of fission products from the particles if the SiC layer is completely penetrated. The experimental section of this report describes the results of work at General Atomic concerning the reaction of fission products with silicon carbide. The discussion section describes data obtained by various laboratories and includes (1) a description of the fission products which have been found to react with SiC; (2) a description of the kinetics of silicon carbide thinning caused by fission product reaction during out-of-pile thermal gradient heating and the application of these kinetics to in-pile irradiation; and (3) a comparison of silicon carbide thinning in LEU and HEU fuels.

  10. First principle identification of SiC monolayer as an efficient catalyst for CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sinthika, S., E-mail: ranjit.t@res.srmuniv.ac.in, E-mail: sinthika90@gmail.com; Thapa, Ranjit, E-mail: ranjit.t@res.srmuniv.ac.in, E-mail: sinthika90@gmail.com [SRM Research Institute, SRM University, Kattankulathur 603203, Tamil Nadu (India); Reddy, C. Prakash [Department of Physics and Nanotechnology, SRM University, Kattankulathur 603203, Tamil Nadu (India)

    2015-06-24

    Using density functional theory, we investigated the electronic properties of SiC monolayer and tested its catalytic activity toward CO oxidation. The planar nature of a SiC monolayer is found to stable and is a high band gap semiconductor. CO interacts physically with SiC surface, whereas O{sub 2} is adsorbed with moderate binding. CO oxidation on SiC monolayer prefers the Eley Rideal mechanism over the Langmuir Hinshelwood mechanism, with an easily surmountable activation barrier during CO{sub 2} formation. Overall metal free SiC monolayer can be used as efficient catalyst for CO oxidation.

  11. Si3N4/SiC nanocomposite powder from a preceramic polymeric network based on poly(methylsilane as the SiC precursor

    Directory of Open Access Journals (Sweden)

    Maurício F. Gozzi

    2001-01-01

    Full Text Available Si3N4/SiC nanocomposite powders were obtained from a preceramic polymeric network based on poly(methylsilane as the in situ quasi-stoichiometric SiC source. These powders were constituted of nanosized SiC particles homogeneously distributed in the Si3N4 particulate matrix. beta-SiC whiskers were grown at 1400 °C in the pores of the matrix. At 1600 °C, the alpha -> beta Si3N4 phase transition took place, but no elemental silicon from Si3N4 decomposition was detected, evidencing the protective effect of the SiC phase.

  12. PhySIC: a veto supertree method with desirable properties.

    Science.gov (United States)

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

    2007-10-01

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

  13. Effects of surface oxide species and contents on SiC slurry viscosity

    Institute of Scientific and Technical Information of China (English)

    NING Shufan; LI Hongyan; CHEN Wei; LIU Bin; CHEN Shoutian

    2005-01-01

    The disadvantageous effects of colloidal SiO2 layer and micro-content of metal oxide adsorbed on SiC powder surface on SiC slurry stable dispersion were studied, and the novel method to avoid this disadvantage was proposed. By acidwashing, on the one hand, because the maximum Zeta potential of SiC powder increases to 72.49 mV with the decreasing content of metal oxide adsorbed on the SiC powder surface, the repulsion force between SiC powders that dispersed in slurry is enhanced, thus the SiC powder can be fully dispersed in slurry. On the other hand, after HF acidwashing, with the OH- group adsorbed on SiC powder surface destroyed and replaced by the F- ion, the hydrogen bond adsorbed on the OH-group is also destroyed. Therefore, the surface property of the SiC powder is changed from hydrophilic to hydrophobic;H2O that adsorbed on SiC powder surface is released and can flow freely, and it actually increases the content of the effective flow phase in the slurry. These changes of SiC powder surface property can be proved by XPS and FTIR analysis. Fivolume fraction of SiC powder in the slurry is maximized to 61.5 vol.%.

  14. Crack Propagation Behaviors of Multi-Layered SiC Composite Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejong; Lee, Donghee; Lee, Hyeon-Geun; Park, Ji Yeon; Kim, Weon-Ju [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    SiC composite cladding has various advantages compared to current Zr alloy cladding in terms of accident resistance and neutron economy. However, its brittle properties and corresponding low reliability make it difficult for a use of SiC ceramics as cladding materials. In this study, fracture behaviors of several SiC composite cladding tubes, particularly crack propagation behavior were evaluated using an acoustic emission method. AE analysis is a useful tool for examination of the multi-layered SiC composite with complex structure which provides information of crack propagation. Failure of an inner monolith SiC in the triplex SiC composite tube will cause significant problems such as hermeticity, degradation of SiC{sub f}/SiC. Duplex SiC composite might be the alternative.

  15. Preparation and mechanical properties of SiC/2024 composite by semisolid casting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A SiC/2024 composite was made by semisolid casting. The wetting between SiC and Al matrix is improved by treating SiC particles at a high temperature, coating K2ZrF6, and adding Mg to the Al melt. An effective way to remove the gas around SiC particles was also found. Microsturctures were observed under optical microscope (OM) and scanning electron microscopy (SEM). The results show that SiC particles and Al matrix are well bonded and no gaps or cavities around the particles are observed. SiC particles distribute homogeneously in the Al matrix. The existence of SiC particles results in the increase of wear resistance and strength.

  16. LOW ACTIVATION JOINING OF SIC/SIC COMPOSITES FOR FUSION APPLICATIONS: MODELING DUAL-PHASE MICROSTRUCTURES AND DISSIMILAR MATERIAL JOINTS

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.; Ferraris, M.; Katoh, Y.

    2016-03-31

    Finite element continuum damage models (FE-CDM) have been developed to simulate and model dual-phase joints and cracked joints for improved analysis of SiC materials in nuclear environments. This report extends the analysis from the last reporting cycle by including results from dual-phase models and from cracked joint models.

  17. Synthesis of whiskers of SiC microwave assisted; Sintesis de whiskers de SiC asistida por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Garza-Mendez, F. J.; Vanegas, A. J.; Vazquez, B. A.; Garza-Paz, J.

    2013-06-01

    We developed a new process for the synthesis of SiC whiskers assisted by microwaves; this is based on the mixture of silica xerogels and graphite powder. As energy source were used microwaves of 2.45 GHz and 1.0 kW of power RMS. On the other hand, mesoporous silica was synthesized via sol-gel, the precursors used were TEOS/H{sub 2}O and ethanol. Through analysis of the BET is determined the value of average pore size (3.0 nm) and the surface area (1090 m2/g).By mean of X-Ray diffraction it was demonstrated that the silica obtained is an amorphous solid and, the powders obtained in the microwave synthesis are {beta}-SiC. Synthesized SiC powders were observed using a SEM in secondary electron mode, it was observed that this powders consists of SiC whiskers. The effect of microwaves on the synthesis of whiskers of SiC is discussed in the present work. (Author) 19 refs.

  18. ISLAM DAN RADIKALISME: Upaya Antisipasi dan Penanggulangannya

    Directory of Open Access Journals (Sweden)

    Idrus Ruslan

    2017-02-01

    Full Text Available Sejak tragedi pemboman WTC tanggal 11 September 2001 yang disusul dengan rangkaian peledakan bom di sejumlah negara, banyak orang non Muslim yang berasumsi bahwa ajaran Islam identik dengan radikalisme. Walaupun assumsi yang berkembang itu dapat dimaklumi, namun keyakinan tersebut tentu saja tidak sepenuhnya benar. Karena meskipun terdapat sekelompok orang Islam yang berbuat radikal, akan tetapi mayoritas Muslim justru bertentangan dengan mereka. Lagi pula, jika dicermati secara mendalam, sesungguhnya Islam sama sekali tidak mentolerir tindakan radikal. Ia adalah agama kasih sayang yang sangat mendodrong penganutnya untuk berbuat baik terhadap orang lain, termasuk kepada orang-orang non-Muslim. Artikel ini menawarkan beberapa upaya strategis dalam mengantisipasi dan menanggulangi bahaya radikalisme-terorisme.

  19. BAHAYA RADIASI DAN CARA PROTEKSINYA

    Directory of Open Access Journals (Sweden)

    Badunggawa P

    2014-09-01

    Full Text Available Radiasi yang kita terima setiap saat, termasuk radiasi untuk tujuan kedokteran, mempunyai dampak positif dan negatif terhadap keselamatan manusia dan lingkungan. Dampak positif dari radiasi terhadap keselamatan manusia diantaranya adalah digunakan sebagai pengobatan dan dampak negatifnya adalah tergantung dari besar dosis yang diterima diantaranya adalah mulai dari mual, muntah, pusing-pusing, rambut rontok, menyebabkan kanker, diturunkan secara genetik, dan yang lebih berbahaya lagi adalah menyebabkan kematian. Oleh karena itu kita harus berhati-hati terhadap bahaya yang ditimbulkannya, baik terhadap pekerja radiasi maupun masyarakat umum termasuk pasien. Perlindungan terhadap bahaya yang ditimbulkan radiasi ini dikenal dengan istilah proteksi radiasi. Sehingga dosis yang diterima pertahun oleh pekerja atau masyarakat umum tidak melebihi batas dosis yang ditetapkan oleh Bapeten. Berbagai upaya telah dilakukan untuk meminimalkan bahaya tersebut sehingga pekerja dan pasien merasa aman melakukan dan dikenai tindakan medik.[medicina 2009;40:47-51].  

  20. Sifat Anatomi dan Fisis Kelapa Hibrida

    OpenAIRE

    Hutabarat, Marihot Hamonangan

    2010-01-01

    Penelitian ini bertujuan untuk mengevaluasi sifat anatomis dan fisis batang kelapa hibrida. Ciri anatomi diamati langsung pada sampel dan menggunakan mikroskop untuk pengamatan dimensi seratnya, dan pengujian sifat fisis menggunakan British Standard. Sifat anatomis dan fisis batang kelapa hibrida bervariasi menurut ketinggian dan kedalaman. Struktur anatomis batang kelapa hibrida didominasi oleh vascular bundle dan parenkim. Serat kayu dapat ditemukan didalam vascular bundle dengan rata-r...

  1. Nilai Dan Fungsi Ndungndungen Karo

    OpenAIRE

    Rosita Ginting

    2010-01-01

    Tesis ini berjudul “Nilai dan Fungsi Ndungndungen Karo”. Tesis ini menjabarkan tentang macam-macam Ndungndungen Karo, nilai-nilai yang terkandung dalam Ndungndungen Karo, fungsi Ndungndungen Karo, dan bagaimana penggunaan Ndungndungen Karo pada saat sekarang ini. Metode yang dipakai dalam penelitian ini adalah metode deskriptif kualitatif, dengan teknik rekaman dan interviu. Metode kepustakaan juga digunakan dalam penelitian ini karena data sekunder dari penelitian ini adalah data-data ya...

  2. Kloning Dan Rekayasa Reproduksi

    Directory of Open Access Journals (Sweden)

    Sulchan Sofoewan

    1997-06-01

    Full Text Available REKAYASA reproduksi yang disebut Assisted Reproductive Techniques (ART atau tehnik tehnik reproduksi dengan tanpa melakukan senggama tetapi dengan bantuan secara medik, atau setiap manipulasi terhadap bagian prekreatif (reproduksi siklus kehidupan. Rekayasa reproduksi, rekayasa genetik dan kloning embrio cenderung untuk saling menunjang (sinergetik. Rekayasa genetik dan klonasi sel embrional dari hasil fertilisasi tadi dapat dilibatkan pada ART sebelum embrio ditransfer kedalam rahim. Untuk pasangan yang suaminya belum memenuhi syarat untuk fertilisasi in vitro karena jumlah spermatozoanya kurang ditempuh dengan cara menyuntikkan spermatozoa langsung kedalam ovum/oosit dengan cara mikro manipulasi/mikro injeksi yang dikenal dengan istilah lCZI (Intracytoplasmic Sperm Injection atau SUZI (Subzonal Sperm Insemination.

  3. En kamp om dans

    DEFF Research Database (Denmark)

    Zachariassen, Annette

    2004-01-01

    Hvordan er det muligt at medtænke et legende og "kæmpende" element i det faglige indholdsområde musik, bevægelse og kropsudtryk/dans? og hvordan er det muligt at lade sig inspirere af elementer fra genren elektric boogie-battel og brasiliansk kampdans "Capoeira" i tilrettelæggelse af et undervisn......Hvordan er det muligt at medtænke et legende og "kæmpende" element i det faglige indholdsområde musik, bevægelse og kropsudtryk/dans? og hvordan er det muligt at lade sig inspirere af elementer fra genren elektric boogie-battel og brasiliansk kampdans "Capoeira" i tilrettelæggelse af et...

  4. Pd/CeO2/SiC Chemical Sensors

    Science.gov (United States)

    Lu, Weijie; Collins, W. Eugene

    2005-01-01

    The incorporation of nanostructured interfacial layers of CeO2 has been proposed to enhance the performances of Pd/SiC Schottky diodes used to sense hydrogen and hydrocarbons at high temperatures. If successful, this development could prove beneficial in numerous applications in which there are requirements to sense hydrogen and hydrocarbons at high temperatures: examples include monitoring of exhaust gases from engines and detecting fires. Sensitivity and thermal stability are major considerations affecting the development of high-temperature chemical sensors. In the case of a metal/SiC Schottky diode for a number of metals, the SiC becomes more chemically active in the presence of the thin metal film on the SiC surface at high temperature. This increase in chemical reactivity causes changes in chemical composition and structure of the metal/SiC interface. The practical effect of the changes is to alter the electronic and other properties of the device in such a manner as to degrade its performance as a chemical sensor. To delay or prevent these changes, it is necessary to limit operation to a temperature CeO2 films is based partly on the observation that nanostructured materials in general have potentially useful electrical properties, including an ability to enhance the transfer of electrons. In particular, nanostructured CeO2, that is CeO2 with nanosized grains, has shown promise for incorporation into hightemperature electronic devices. Nanostructured CeO2 films can be formed on SiC and have been shown to exhibit high thermal stability on SiC, characterized by the ability to withstand temperatures somewhat greater than 700 C for limited times. The exchanges of oxygen between CeO2 and SiC prevent the formation of carbon and other chemical species that are unfavorable for operation of a SiC-based Schottky diode as a chemical sensor. Consequently, it is anticipated that in a Pd/CeO2/SiC Schottky diode, the nanostructured interfacial CeO2 layer would contribute to

  5. Perancangan dan Implementasi Modul Praktikum

    Directory of Open Access Journals (Sweden)

    Gita Indah Hapsari

    2015-05-01

    Full Text Available Kemajuan teknologi berbasis komputer berkembang dengan sangat pesat. Seiring dengan perkembangan jaman, kemajuan  tersebut memberikan pengaruh  terhadap  perubahan cara penyampaian pengajaran yang mengarah pada penggunaan jenis media penyampaian. Praktikum merupakan salah satu bentuk pengajaran yang memberikan pengalaman belajar secara nyata terhadap kondisi sebenarnya di lapangan mengenai penggunaan dan implementasi alat praktek yang berhubungan dengan berbagai materi yang dipelajari oleh mahasiswa dan memiliki tujuan untuk memberikan keterampilan dan pengenalan terhadap mahasiswa/peserta didik. Penelitian ini melakukan implementasi teknologi augmented reality terhadap salah satu modul praktikum yaitu pengenalan tata letak hardware dan Port I/O pada motherboard dan bertujuan sebagai alat bantu penyampaian pengajaran praktikum. Pengimplementasian teknologi augmented reality melibatkan aksi oleh user terhadap media penangkapan gambar motherboard menggunakan web camera dan tampilan pemetaan tata letak hardware dan port i/o pada motherboard. Penelitian telah diimplementasikan dan diujicoba terhadap 3 kelas dengan 97 responder. Adapun hasil dari penelitiannya adalah 83% responder menyukai aplikasi, 77% memahami materi, 84,5% menginginkan aplikasi ini menjadi alat bantu ajar, 65,98% meminta materi untuk dilengkapi dan diperbanyak, 77,3% dapat belajar mandiri menggunakan aplikasi ini, tanpa bantuan dari dosen ataupun asisten.

  6. NYERI KEPALA DAN GANGGUAN TIDUR

    Directory of Open Access Journals (Sweden)

    Lina Kamelia

    2014-09-01

    Full Text Available Nyeri kepala dan tidur merupakan dua fenomena yang saling mempengaruhi dengan patomekanisme yang kompleks. Nyeri kepala primer, terutama migren, nyeri kepala klaster dan hypnic headache dapat timbul karena pengurangan waktu tidur, parasomnia, maupun gangguan pada regulasi arsitektur tidur terutama fase rapid eye movement. Sebaliknya, adanya nyeri kepala memicu timbulnya berbagai macam gangguan tidur. Studi pencitraan otak dan biokimia menunjukkan peranan penting melatonin dan nukleus suprachiasmatik   yang mengalami disfungsi pada penderita nyeri kepala yang berhubungan dengan gangguan tidur. [MEDICINA 2013;44:101-104].

  7. SEKS DAN BUGAR

    Directory of Open Access Journals (Sweden)

    Ira Paramastri

    2016-10-01

    Full Text Available Barilah, seorang eksekutif perempuan datang ke klinik psikologi dengan keluhan "malas bahkan tidak terangsang tatkala suaminya mengajak bermain seks", atau keluhan Edo, seorang menejer muda "saya jengkel dengan diri saya sendiri karena saya tidak dapat ereksi dengan keras", atau keluhan pasangan muda wanita karir dan pengusaha Retno-Rubi "saat atau serampung hubungan seksual selalu dibarengi rasa nyeri/sakit, sungguh menyebalkan".

  8. ASIMETRI INFORMASI DAN UNDERPRICING

    Directory of Open Access Journals (Sweden)

    Tety Anggita Safitri

    2013-03-01

    Full Text Available Tujuan penelitian ini adalah untuk menguji pengaruh asimetri informasi terhadap underpricing. Penelitian ini menggunakan sampel 63 perusahaan yang melakukan penawaran umum perdana di Bursa Efek Indonesia dalam kurun waktu 2005-2010. Analisis data menggunakan regresi linier berganda, yaitu menguji proksi asimetri informasi yang terdiri atas ukuran perusahaan, umur perusahaan, proporsi saham yang ditawarkan kepada masyarakat, reputasi underwriter dan reputasi auditor terhadap underpricing. Hasil penelitian ini mengindikasikan bahwa reputasi underwriter dan reputasi auditor berpengaruh terhadap underpricing. Ukuran perusahaan, umur perusahaan dan proporsi saham yang ditawarkan tidak berpengaruh terhadap underpricing.The aim of this research is to examine the effect of assymetric information on underpricing. This research used a sample of 63 companies that make initial public offering on the Indonesia Stock Exchange in the period of 2005-2010. The data analysis is using multiple linear regression, which is testing the proxy of asymmetric information which consists of the firm size, the firm age, the proportion of shares offered to the public, underwriter reputation and auditor reputation on underpricing. This research indicates that underwriter reputation and auditor reputation have a significant effect on underpricing. The firm size, the firm age and the proportion of shares offered to the public have no significant effect on underpricing.

  9. ASIMETRI INFORMASI DAN UNDERPRICING

    Directory of Open Access Journals (Sweden)

    Tety Anggita Safitri

    2013-03-01

    Full Text Available Tujuan penelitian ini adalah untuk menguji pengaruh asimetri informasi terhadap underpricing. Penelitian ini menggunakan sampel 63 perusahaan yang melakukan penawaran umum perdana di Bursa Efek Indonesia dalam kurun waktu 2005-2010. Analisis data menggunakan regresi linier berganda, yaitu menguji proksi asimetri informasi yang terdiri atas ukuran perusahaan, umur perusahaan, proporsi saham yang ditawarkan kepada masyarakat, reputasi underwriter dan reputasi auditor terhadap underpricing. Hasil penelitian ini mengindikasikan bahwa reputasi underwriter dan reputasi auditor berpengaruh terhadap underpricing. Ukuran perusahaan, umur perusahaan dan proporsi saham yang ditawarkan tidak berpengaruh terhadap underpricing.The aim of this research is to examine the effect of assymetric information on underpricing. This research used a sample of 63 companies that make initial public offering on the Indonesia Stock Exchange in the period of 2005-2010. The data analysis is using multiple linear regression, which is testing the proxy of asymmetric information which consists of the firm size, the firm age, the proportion of shares offered to the public, underwriter reputation and auditor reputation on underpricing. This research indicates that underwriter reputation and auditor reputation have a significant effect on underpricing. The firm size, the firm age and the proportion of shares offered to the public have no significant effect on underpricing.

  10. Astrocyte-Dependent Slow Inward Currents (SICs) Participate in Neuromodulatory Mechanisms in the Pedunculopontine Nucleus (PPN)

    Science.gov (United States)

    Kovács, Adrienn; Pál, Balázs

    2017-01-01

    Slow inward currents (SICs) are known as excitatory events of neurons caused by astrocytic glutamate release and consequential activation of neuronal extrasynaptic NMDA receptors. In the present article we investigate the role of these astrocyte-dependent excitatory events on a cholinergic nucleus of the reticular activating system (RAS), the pedunculopontine nucleus (PPN). It is well known about this and other elements of the RAS, that they do not only give rise to neuromodulatory innervation of several areas, but also targets neuromodulatory actions from other members of the RAS or factors providing the homeostatic drive for sleep. Using slice electrophysiology, optogenetics and morphological reconstruction, we revealed that SICs are present in a population of PPN neurons. The frequency of SICs recorded on PPN neurons was higher when the soma of the given neuron was close to an astrocytic soma. SICs do not appear simultaneously on neighboring neurons, thus it is unlikely that they synchronize neuronal activity in this structure. Occurrence of SICs is regulated by cannabinoid, muscarinic and serotonergic neuromodulatory mechanisms. In most cases, SICs occurred independently from tonic neuronal currents. SICs were affected by different neuromodulatory agents in a rather uniform way: if control SIC activity was low, the applied drugs increased it, but if SIC activity was increased in control, the same drugs lowered it. SICs of PPN neurons possibly represent a mechanism which elicits network-independent spikes on certain PPN neurons; forming an alternative, astrocyte-dependent pathway of neuromodulatory mechanisms. PMID:28203147

  11. Effects of SiC on Properties of Cu-SiC Metal Matrix Composites

    Science.gov (United States)

    Efe, G. Celebi; Altinsoy, I.; Ipek, M.; Zeytin, S.; Bindal, C.

    2011-12-01

    This paper was focused on the effects of particle size and distribution on some properties of the SiC particle reinforced Cu composites. Copper powder produced by cementation method was reinforced with SiC particles having 1 and 30 μm particle size and sintered at 700 °C. SEM studies showed that SiC particles dispersed in copper matrix homogenously. The presence of Cu and SiC components in composites were verified by XRD analysis technique. The relative densities of Cu-SiC composites determined by Archimedes' principle are ranged from 96.2% to 90.9% for SiC with 1 μm particle size, 97.0 to 95.0 for SiC with 30 μm particle size. Measured hardness of sintered compacts varied from 130 to 155 HVN for SiC having 1 μm particle size, 188 to 229 HVN for SiC having 1 μm particle size. Maximum electrical conductivity of test materials was obtained as 80.0% IACS (International annealed copper standard) for SiC with 1 μm particle size and 83.0% IACS for SiC with 30 μm particle size.

  12. COMMUNICATION MEDIATIQUE : LES APPORTS DE LA PSYCHOLOGIE SOCIALE ; Pour une pluralité épistémologique, théorique et méthodologique en SIC

    OpenAIRE

    Courbet, Didier

    2004-01-01

    L'objectif de cette note d'habilitation à diriger des recherches est à la fois de dresser une synthèse critique de mes recherches, de discuter des perspectives théoriques, méthodologiques –voire épistémologiques– qu'elles ouvrent et d'expliquer comment je souhaite les poursuivre, tant au niveau scientifique qu'institutionnel. S'insérant dans une tradition de recherches des SIC, mes travaux portent sur les interactions production–dispositif–réception médiatiques situées au sein d'un large ense...

  13. Communication médiatique : les apports de la psychologie sociale. Pour une pluralité épistémologique, théorique et méthodologique en SIC

    OpenAIRE

    Courbet, Didier

    2004-01-01

    pour joindre l'auteur : ; L'objectif de cette note d'habilitation à diriger des recherches est à la fois de dresser une synthèse critique de mes recherches, de discuter des perspectives théoriques, méthodologiques –voire épistémologiques– qu'elles ouvrent et d'expliquer comment je souhaite les poursuivre, tant au niveau scientifique qu'institutionnel. S'insérant dans une tradition de recherches des SIC, mes travaux portent sur les interactions production–dispositif–ré...

  14. DIVERSITAS DAN KERAPATAN MANGROVE, GASTROPODA DAN BIVALVIA DI ESTUARI PERANCAK, BALI

    OpenAIRE

    2011-01-01

    Penelitian ini bertujuan membandingkan diversitas dan kerapatan mangrove dengan kepadatan gastropoda dan bivalvia di mangrove alami dan rehabilitasi. Pengukuran ekosistem mangrove menggunakan transek kuadrat 10 m x 10 m. Kelimpahan dan kepadatan gastropoda dan bialvia menggunakan transek kuadrat berukuran 1 m x 1 m. Analisis nMDS, cluster untuk melihat hubungan karekteristik mangrove alami dan rehabilitasi dianalisis secara deskriptif dan analisis regresi untuk mendetermi...

  15. Creep behavior for advanced polycrystalline SiC fibers

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, G.E.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States); Kohyama, Akira [Kyoto Univ. (Japan)] [and others

    1997-04-01

    A bend stress relaxation (BSR) test has been utilized to examine irradiation enhanced creep in polycrystalline SiC fibers which are under development for use as fiber reinforcement in SiC/SiC composite. Qualitative, S-shaped 1hr BSR curves were compared for three selected advanced SiC fiber types and standard Nicalon CG fiber. The temperature corresponding to the middle of the S-curve (where the BSR parameter m = 0.5) is a measure of a fiber`s thermal stability as well as it creep resistance. In order of decreasing thermal creep resistance, the measured transition temperatures were Nicalon S (1450{degrees}C), Sylramic (1420{degrees}C), Hi-Nicalon (1230{degrees}C) and Nicalon CG (1110{degrees}C).

  16. POWDER INJECTION MOLDING OF SIC FOR THERMAL MANAGEMENT V

    Directory of Open Access Journals (Sweden)

    Valmikanathan Onbattuvelli

    2012-06-01

    Full Text Available Silicon carbide (SiC exhibits many functional properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of ceramics into fully dense microstructures. Increasing the packing density of the starting powders is one effective route to achieve high sintered density and dimensional precision. The present paper presents an in-depth study on the effects of nanoparticle addition on the powder injection molding process (PIM of SiC powder-polymer mixtures. In particular, bimodal mixtures of nanoscale and sub-micrometer particles are found to have significantly increased powder packing characteristics (solids loading in the powder-polymer mixtures. The influence of nanoparticle addition on the multi-step PIM process is examined. The above results provide new perspectives which could impact a wide range of materials, powder processing techniques and applications.

  17. Surface engineering of SiC via sublimation etching

    Science.gov (United States)

    Jokubavicius, Valdas; Yazdi, Gholam R.; Ivanov, Ivan G.; Niu, Yuran; Zakharov, Alexei; Iakimov, Tihomir; Syväjärvi, Mikael; Yakimova, Rositsa

    2016-12-01

    We present a technique for etching of SiC which is based on sublimation and can be used to modify the morphology and reconstruction of silicon carbide surface for subsequent epitaxial growth of various materials, for example graphene. The sublimation etching of 6H-, 4H- and 3C-SiC was explored in vacuum (10-5 mbar) and Ar (700 mbar) ambient using two different etching arrangements which can be considered as Si-C and Si-C-Ta chemical systems exhibiting different vapor phase stoichiometry at a given temperature. The surfaces of different polytypes etched under similar conditions are compared and the etching mechanism is discussed with an emphasis on the role of tantalum as a carbon getter. To demonstrate applicability of such etching process graphene nanoribbons were grown on a 4H-SiC surface that was pre-patterned using the thermal etching technique presented in this study.

  18. Nucleation and growth of polycrystalline SiC

    DEFF Research Database (Denmark)

    Kaiser, M.; Schimmel, S.; Jokubavicius, V.

    2014-01-01

    R polytypes. It is found that pyrolytic graphite results in enhanced texturing of the nucleating gas species. Reducing the pressure leads to growth of the crystallites until a closed polycrystalline SiC layer containing voids with a rough surface is developed. Bulk growth was conducted at 35 mbar Ar...... pressure at 2250°C in diffusion limited mass transport regime generating a convex shaped growth form of the solid-gas interface leading to lateral expansion of virtually [001] oriented crystallites. Growth at 2350°C led to the stabilization of 6H polytypic grains. The micropipe density in the bulk strongly......The nucleation and bulk growth of polycrystalline SiC in a 2 inch PVT setup using isostatic and pyrolytic graphite as substrates was studied. Textured nucleation occurs under near-thermal equilibrium conditions at the initial growth stage with hexagonal platelet shaped crystallites of 4H, 6H and 15...

  19. Progress of d0 magnetism in SiC

    Science.gov (United States)

    Wang, Yutian; Liu, Chenguang; Zhang, Yuming

    2017-03-01

    The properties of defect-induced ferromagnetism ({{{d}}}0 magnetism) in SiC belong to carbon-based material which has been systematically investigated after graphite. In this paper, we reviewed our research progress about {{{d}}}0 magnetism in two aspects, i.e., magnetic source and magnetic coupling mechanism. The {{{V}}}{{Si}} {{{V}}}{{C}} divacancies have been evidenced as the probable source of {{{d}}}0 magnetism in SiC. To trace the ferromagnetic source in microscopic and electronic view, the p electrons of the nearest-neighbor carbon atoms, which are around the {{{V}}}{{Si}} {{{V}}}{{C}} divacancies, are sourced. For magnetic coupling mechanism, a higher divacancy concentration leads to stronger paramagnetic interaction but not stronger ferromagnetic coupling. So the {{{d}}}0 magnetism can probably be explained as a local effect which is incapable of scaling up with the volume.

  20. Excited States of the divacancy in SiC

    Science.gov (United States)

    Bockstedte, Michel; Garratt, Thomas; Ivady, Viktor; Gali, Adam

    2014-03-01

    The divacancy in SiC - a technologically mature material that fulfills the necessary requirements for hosting defect based quantum computing - is a good candidate for implementing a solid state quantum bit. Its ground state is isovalent to the NV center in diamond as demonstrated by density functional theory (DFT). Furthermore, coherent manipulation of divacancy spins in SiC has been demonstrated. The similarities to NV might indicate that the same inter system crossing (ICS) from the high to the low spin state is responsible for its spin-dependent fluorescent signal. By DFT and a DFT-based multi-reference hamiltonian we analyze the excited state spectrum of the defects. In contrast to the current picture of the spin dynamics of the NV center, we predict that a static Jahn-Teller effect in the first excited triplet states governs an ICS both with the excited and ground state of the divacancy.

  1. STUDI PEMODELAN DAN PERHITUNGAN TRANSPORT MONTE CARLO DALAM TERAS HTR PEBBLE BED

    Directory of Open Access Journals (Sweden)

    Zuhair .

    2013-01-01

    Full Text Available Konsep sistem energi VHTR baik yang berbahan bakar pebble (VHTR pebble bed maupun blok prismatik (VHTR prismatik menarik perhatian fisikawan reaktor nuklir. Salah satu kelebihan teknologi bahan bakar bola adalah menawarkan terobosan teknologi pengisian bahan bakar tanpa harus menghentikan produksi listrik. Selain itu, partikel bahan bakar pebble dengan kernel uranium oksida (UO2 atau uranium oksikarbida (UCO yang dibalut TRISO dan pelapisan silikon karbida (SiC dianggap sebagai opsi utama dengan pertimbangan performa tinggi pada burn-up bahan bakar dan temperatur tinggi. Makalah ini mendiskusikan pemodelan dan perhitungan transport Monte Carlo dalam teras HTR pebble bed. HTR pebble bed adalah reaktor berpendingin gas temperatur tinggi dan bermoderator grafit dengan kemampuan kogenerasi. Perhitungan dikerjakan dengan program MCNP5 pada temperatur 1200 K. Pustaka data nuklir energi kontinu ENDF/B-V dan ENDF/B-VI dimanfaatkan untuk melengkapi analisis. Hasil perhitungan secara keseluruhan menunjukkan konsistensi dengan nilai keff yang hampir sama untuk pustaka data nuklir yang digunakan. Pustaka ENDF/B-VI (66c selalu memproduksi keff lebih besar dibandingkan ENDF/B-V (50c maupun ENDF/B-VI (60c dengan bias kurang dari 0,25%. Kisi BCC memprediksi keff hampir selalu lebih kecil daripada kisi lainnya, khususnya FCC. Nilai keff kisi BCC lebih dekat dengan kisi FCC dengan bias kurang dari 0,19% sedangkan dengan kisi SH bias perhitungannya kurang dari 0,22%. Fraksi packing yang sedikit berbeda (BCC= 61%, SH= 60,459% tidak membuat bias perhitungan menjadi berbeda jauh. Estimasi keff ketiga model kisi menyimpulkan bahwa model BCC lebih bisa diadopsi dalam perhitungan HTR pebble bed dibandingkan model FCC dan SH. Verifikasi hasil estimasi ini perlu dilakukan dengan simulasi Monte Carlo atau bahkan program deterministik lainnya guna optimisasi perhitungan teras reaktor temperatur tinggi.   Kata-kunci: kernel, TRISO, bahan bakar pebble, HTR pebble bed

  2. IJTIHAD KONTEMPORER (Problem dan Solusinya

    Directory of Open Access Journals (Sweden)

    Mustaqim Mustaqim

    2011-04-01

    Full Text Available Ijtiha>d adalah merupakan bahasan yang tak henti-hentinya menjadi kajian ketat para ulama sejak dulu sampai kini, seperti imam al-Ghaza>li> membahas dalam bukunya al mustasfa, demikian juga imam assyaukani membahas dalam bukunya irsyadul puhul dan masih banyak lagi ulama yung membahas dalam masalah ijtiha>d ini, Begitu juga dari kalangan ulama kontemporer seperti, Shaykh Ah}mad Ibra>hi>m, Shaykh ‘Abd al-Wahha>b Khala>f, Dr. Yu>suf al-Qarad}awi>, Dr. T{a>ha> Jabi>r dan masih banyak lagi selain mereka. Bersama itu, pintu ijtiha>d tak pernah tertutup, karena kehidupan masih terus berlanjut, dan kejadian-kejadian masih terus berkembang, timbulnya krisis ekonomi dan sosial, rangkaian masalah dan berbagai macam solusinya, desakan kejadian yang tak pernah dipersiapkan oleh manusia yang menimbulkan aneka ragam kesulitan, dan terus mengakar sampai menyelami kehidupan tekhnologi, perdagangan, atau kehidupan individu dan umum. Berawal dari sini maka merupakan cambuk bagi seorang muslim dengan kebebasan berpikirnya untuk mengerahkan segala kemampuannya terhadap seluruh masalah, sebab islam adalah agama kehidupan yang mencakup segala aspek, Islam bukan hanya berurusan dengan masalah akhirat saja, tapi Islam lahir dalam bentuk yang luas, mampu mengobati penyakit sosial, ekonomi, internasional, dll, dan fiqih sendiri bukan hanya merupakan peraturan belaka, melainkan fiqih mencakup segala masalah tergantung kejadian dan kebutuhan, fiqih masih siap menerima perubahan selama masih tetap dalam rel qur’an dan sunnah, dari sinilah perlu adanya ijtiha>d, Ijtiha>d merupakan hal yang terbuka bagi seorang muslim agar merasakan kebebasan berfikir yang sempurna karena ijtiha>d adalah merupakan sebuah bukti akan luas dan mudahnya syariat islam.

  3. Evaluation of SiC schottky diodes using pressure contacts

    OpenAIRE

    Ortiz Gonzalez, Jose; Alatise, Olayiwola; Aliyu, Attahir; Rajaguru, Pushparajah; Castellazzi, Alberto; Ran, Li; Mawby, Philip; Bailey, Chris

    2017-01-01

    The thermomechanical reliability of SiC power devices and modules is increasingly becoming of interest especially for high power applications where power cycling performance is critical. Press-pack assemblies are a trusted and reliable packaging solution that has traditionally been used for high power thyristor- based applications in FACTS/HVDC, although press-pack IGBTs have become commercially available more recently. These press-pack IGBTs require anti-parallel PiN diodes for enabling reve...

  4. Etude du frittage réactif dans le système Al2O3-AIN-MgO. Application à l'élaboration d'une céramique spinelle oxynitrurée transparente

    OpenAIRE

    GRANON, Arielle

    1994-01-01

    Pas de résumé en anglais; La céramique spinelle oxynitrure d'aluminium et de magnésium est obtenue transparente dans le visible et l'infra-rouge par frittage réactif d'un mélange de poudres d'alumine, nitrure d'aluminium et oxyde de magnésium. L'oxynitrure d'aluminium et de magnésium se forme par réaction en phase solide entre une structure spinelle hôte (aluminate de magnésium ou oxynitrure d'aluminium) et du nitrure d'aluminium ou de l'oxyde de magnésium. Son apparition est généralement eff...

  5. Acoustic Response of Laminated SiC Ceramics

    Science.gov (United States)

    Esquivel-Sirvent, Raul; Noguez, Cecilia

    1996-03-01

    We present a theoretical calculation of the reflectivity of compressional elastic waves propagating through a laminated structure made of alternate layers of SiC and porous SiC. During fabrication, defects like variation of the period of the structure or variations in the porosity, can be present. By calculating the reflectivity spectra, we can assess the feasibility of using acoustic measuring techniques to characterize these laminated structures. Our results show that, for an ordered structure where the period and porosity of the laminated structure is constant, the reflectivity spectra starts showing the characteristic band structure of waves propagating in infinite superlattices. To simulate fabrication defects, first the period of the structure is changed by randomly varing the thickness of the porous layers. The reflectivity shows that variations in the period induce strong changes in the reflectivity spectra (i.e transmission is enhanced). In comparison, when the period remains constant and the porosity of the SiC porous layers is varied randomly, we observe that even when the porosity changes randomly by up to 50%, the reflectivity spectra does not show significant changes. Finally the case when both period and porosity are varied and when one of the porous layers is missing from the structure will also be discussed.

  6. Atmospheric pressure growth of graphene on SiC(0001)

    Science.gov (United States)

    Seyller, Thomas

    2009-03-01

    Graphene, a single monolayer of sp^2-bonded carbon, is a very unique 2-dimensional electron gas system with electronic properties fundamentally different to other 2DEG systems [1]. Several production routes exist for graphene. Among them, the solid-state decomposition of hexagonal silicon carbide (SiC) surfaces [2] is particularly attractive for the development of graphene based electronics [3,4]. The first part of the presentation gives a brief summary of recent studies on the structural and electronic properties of graphene and few-layer graphene grown on SiC(0001) under ultra-high vacuum (UHV) conditions. The second part of the talk is devoted to recent progress in the growth of large domain graphene films on SiC(0001) in Ar atmosphere. It is shown that growth in Ar ambient leads to a significant improvement of the surface morphology and domain size as well as carrier mobility. [4pt] [1] A.H. Castro Neto, et al., Reviews of Modern Physics, in print (arXiv:0709.1163v2); and references therein. [0pt] [2] A. Charrier, et al., J. Appl. Phys. 92 (2002) 2479. [0pt] [3] C. Berger et al., J. Phys. Chem. B 108 (2004) 19912; C. Berger, et al., Science 312 (2006) 1191. [0pt] [4] A.K. Geim and K.S. Novoselov, Nature Mat. 6 (2007) 183.

  7. A study of SiC decomposition under laser irradiation

    Science.gov (United States)

    Adelmann, B.; Hellmann, R.

    2017-06-01

    In this experimental study we investigate the laser induced thermal decomposition of 4H-Sic under ambient conditions using fiber laser. Using a unique two-color pyrometer setup, we measure the temporal evolution of the temperature in the irradiated zone and determine the decomposition rate for various laser power levels. We find that the temporal evolution of the temperature in the irradiated area exhibits an initial heating phase up to about 1300 K, being characterized by an unaffected SiC surface. Upon an expeditious temperature increase, a decomposition phase follows with temperatures above 1700 K, being accompanied by carbonization of the SiC surface. The decomposed volume depends linearly on the duration of the decomposition phase and increases linearly with laser power. The temperature evaluation of the decomposition speed reveals an Arrhenius-type behavior allowing the calculation of the activation energy for the decomposition under ambient conditions to 613 kJ/mol in the temperature range between 2140 and 2420 K.

  8. Synchronistic preparation of fibre-like SiC and cubic-ZrO{sub 2}/SiC composite from zircon via carbothermal reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Youguo; Liu, Yangai [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Huang, Zhaohui, E-mail: huang118@cugb.edu.cn [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Fang, Minghao [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Hu, Xiaozhi [School of Mechanical and Chemical Engineering, University of Western Australia, Perth, WA 6009 (Australia); Yin, Li; Huang, Juntong [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China)

    2013-01-15

    Graphical abstract: Display Omitted Highlights: ► Zircon carbothermal reduction was carried out in a tailor-made device at high-temperature air atmosphere. ► Fibre-like SiC and cubic-ZrO{sub 2}/SiC composite were obtained synchronically. ► Zirconium and silicon in zircon ore was initial separated. ► [SiO{sub 4}] was mutated to fibre-like SiC, while [ZrO{sub 8}] was transformed to cubic ZrO{sub 2}. ► The SiC were surprisingly enriched in the reducing atmosphere charred coal particles layers by gas–solid reaction. -- Abstract: Fibre-like SiC and cubic-ZrO{sub 2}/SiC composite were prepared respectively from zircon with yttrium oxide addition via carbothermal reduction process at 1600 °C for 4 h in an air atmosphere furnace, where the green samples were immerged in charred coal particles inside a high-temperature enclosed corundum crucible. The reaction products were characterized by XRD, XRF, XPS and SEM. The results indicate that ZrO{sub 2} in the products was mainly existed in the form of cubic phase. The reacted samples mainly contain cubic ZrO{sub 2}, β-SiC and trace amounts of zircon, with the SiC accounting for 14.8 wt%. Furthermore, a large quantity of fibre-like SiC was surprisingly found to concentrate in the charred coal particles layers around the samples. This study obtains fibre-like SiC and cubic-ZrO{sub 2}/SiC composite synchronically from zircon via carbothermal reduction process, which also bring a value-added high-performance application for natural zircon.

  9. Low-energy SiC2H6+ and SiC3H9+ ion beam productions by the mass-selection of fragments produced from hexamethyldisilane for SiC film formations

    Directory of Open Access Journals (Sweden)

    Satoru Yoshimura

    2016-12-01

    Full Text Available We have been attempting to produce low-energy ion beams from fragments produced through the decomposition of hexamethyldisilane (HMD for silicon carbide (SiC film formations. We mass-selected SiC2H6+ and SiC3H9+ ions from fragments produced from HMD, and finally produced low-energy SiC2H6+ and SiC3H9+ ion beams. The ion energy was approximately 100 eV. Then, the ion beams were irradiated to Si(100 substrates. The temperature of the Si substrate was 800°C during the ion irradiation. The X-ray diffraction and Raman spectroscopy of the substrates obtained following SiC2H6+ ion irradiation demonstrated the occurrence of 3C-SiC deposition. On the other hand, the film deposited by the irradiation of SiC3H9+ ions included diamond-like carbon in addition to 3C-SiC.

  10. FTIR-ATR analysis of SiC(000 anti 1) and SiC(0001) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, H.; Kamata, I.; Izumi, K. [Central Research Inst. of Electric Power Industry, Yokosuka (Japan)

    1998-06-01

    Recently developed SiC wafers with large diameter have been utilized to investigate the chemical state of the SiC surfaces by Fourier-transformed infrared attenuated total reflection (FTIR-ATR) spectroscopy with high sensitivity. The ex-situ ATR spectroscopy equipped with a Ge prism was used to study the chemisorbed species on 6H-SiC(000 anti 1) and (0001) surface after the chemical treatment and after the heat treatment in hydrogen. We obtained clear absorption bands attributable to hydrides on the surfaces. The polarity dependencies of Si-H and C-H stretch modes between the 6H-SiC(000 anti 1) and (0001) were discussed. (orig.) 10 refs.

  11. Adsorption of formaldehyde (HCOH) molecule on the SiC sheet: A first-principles study

    Science.gov (United States)

    Wang, Lizhi

    2012-06-01

    We investigated the adsorption of HCOH molecule on the SiC sheet using density functional theory (DFT) calculations. It is found that the C atom of the SiC sheet is the active adsorption site and the HCOH molecule prefers to the C atom rather than the O and H atoms close to the SiC sheet. The calculated charge-transfer, electronic density difference image and the densities of states (DOS) show that the HCOH molecule could be firmly adsorbed by the SiC sheet and the electronic properties of the SiC sheet are affected by the adsorption of HCOH molecule. The SiC sheet would be promising candidate to detect the HCOH gas.

  12. Effect of oxygen content on tensile strength of polymer-derived SiC fibers

    Institute of Scientific and Technical Information of China (English)

    楚增勇; 冯春祥; 宋永才; 王应德; 李效东; 肖加余

    2002-01-01

    Air-curing is usually applied to the polymer-derived SiC fibers and, as a result, oxygen is embedded to the material. An effective relationship between oxygen content of the SiC fibers and mass gain of their precursor fibers was established. Results also showed that oxygen content has a great influence on the mechanical properties and excellent tensile strength is usually obtained at the oxygen content of 12%~13%, similar to the density of SiC fibers. Oxygen content has a positive effect on the ceramic yield, and thus, is good to the density and tensile strength; while, oxygen content is also negative to volume content of SiC phase and crystallization of the SiC fibers, and thus, detrimental to the density and tensile strength. Both of the two effects result in the peak behavior of the tensile strength of SiC fibers.

  13. A Method to Adjust Dielectric Property of SiC Powder in the GHz Range

    Institute of Scientific and Technical Information of China (English)

    Xiaolei Su; Jie Xu; Zhimin Li; Junbo Wang; Xinhai He; Chong Fu; Wancheng Zhou

    2011-01-01

    The SiC powders by Al or N doping have been synthesized by combustion synthesis, using Al powder and NH4Cl powder as the dopants and polytetrafluoroethylene as the chemical activator. Characterization by X-ray diffraction, Raman spectrometer, scanning electron microscopy and energy dispersive spectrometer demonstrates the formation of Al doped SiC, N doped SiC and the Al and N co-doped SiC solid solution powders, respectively. The electric permittivities of prepared powders have been determined in the frequency range of 8.2-12.4 GHz. It indicates that the electric permittivities of the prepared SiC powders have been improved by the pure Al or N doping and decrease by the Al and N co-doping. The paper presents a method to adjust dielectric property of SiC powders in the GHz range.

  14. SEM analysis of ion implanted SiC

    Energy Technology Data Exchange (ETDEWEB)

    Malherbe, Johan B., E-mail: johan.malherbe@up.ac.za [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Berg, N.G. van der; Botha, A.J.; Friedland, E.; Hlatshwayo, T.T.; Kuhudzai, R.J. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Wendler, E.; Wesch, W. [Institut für Festkörperphysik, Friedrich-Schiller-Universität, 07743 Jena (Germany); Chakraborty, P. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Silveira, E.F. da [Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro (Brazil)

    2013-11-15

    SiC is a material used in two future energy production technologies, firstly as a photovoltaic layer to harness the UV spectrum in high efficient power solar cells, and secondly as a diffusion barrier material for radioactive fission products in the fuel elements of the next generation of nuclear power plants. For both applications, there is an interest in the implantation of reactive and non-reactive ions into SiC and their effects on the properties of the SiC. In this study 360 keV Ag{sup +}, I{sup +} and Xe{sup +} ions were separately implanted into 6H–SiC and in polycrystalline SiC at various substrate temperatures. The implanted samples were also annealed in vacuum at temperatures ranging from 900 °C to 1600 °C for various times. In recent years, there had been significant advances in scanning electron microscopy (SEM) with the introduction of an in-lens detector combined with field emission electron guns. This allows defects in solids, such as radiation damage created by the implanted ions, to be detected with SEM. Cross-sectional SEM images of 6H–SiC wafers implanted with 360 keV Ag{sup +} ions at room temperature and at 600 °C and then vacuum annealed at different temperatures revealed the implanted layers and their thicknesses. A similar result is shown of 360 keV I{sup +} ions implanted at 600 °C into 6H–SiC and annealed at 1600 °C. The 6H–SiC is not amorphized but remained crystalline when implanting at 600 °C. There are differences in the microstructure of 6H–SiC implanted with silver at the two temperatures as well as with reactive iodine ions. Voids (bubbles) are created in the implanted layers into which the precipitation of silver and iodine can occur after annealing of the samples. The crystallinity of the substrate via implantation temperature caused differences in the distribution and size of the voids. Implantation of xenon ions in polycrystalline SiC at 350 °C does not amorphize the substrate as is the case with room

  15. SiC Optically Modulated Field-Effect Transistor

    Science.gov (United States)

    Tabib-Azar, Massood

    2009-01-01

    An optically modulated field-effect transistor (OFET) based on a silicon carbide junction field-effect transistor (JFET) is under study as, potentially, a prototype of devices that could be useful for detecting ultraviolet light. The SiC OFET is an experimental device that is one of several devices, including commercial and experimental photodiodes, that were initially evaluated as detectors of ultraviolet light from combustion and that could be incorporated into SiC integrated circuits to be designed to function as combustion sensors. The ultraviolet-detection sensitivity of the photodiodes was found to be less than desired, such that it would be necessary to process their outputs using high-gain amplification circuitry. On the other hand, in principle, the function of the OFET could be characterized as a combination of detection and amplification. In effect, its sensitivity could be considerably greater than that of a photodiode, such that the need for amplification external to the photodetector could be reduced or eliminated. The experimental SiC OFET was made by processes similar to JFET-fabrication processes developed at Glenn Research Center. The gate of the OFET is very long, wide, and thin, relative to the gates of typical prior SiC JFETs. Unlike in prior SiC FETs, the gate is almost completely transparent to near-ultraviolet and visible light. More specifically: The OFET includes a p+ gate layer less than 1/4 m thick, through which photons can be transported efficiently to the p+/p body interface. The gate is relatively long and wide (about 0.5 by 0.5 mm), such that holes generated at the body interface form a depletion layer that modulates the conductivity of the channel between the drain and the source. The exact physical mechanism of modulation of conductivity is a subject of continuing research. It is known that injection of minority charge carriers (in this case, holes) at the interface exerts a strong effect on the channel, resulting in amplification

  16. Analisis dan Optimasi Desain Sistem Reaktor Gas Temperatur Tinggi RGTT200K dan RGTT200KT

    Directory of Open Access Journals (Sweden)

    Mohammad Dhandhang Purwadi

    2013-03-01

    dengan penyelesaian persamaan aljabar linier dari model RGTT200K dan RGTT200KT. Dari analisis dan optimasi ini dihasilkan desain konseptual sistem RGTT200K dan RGTT200KT dengan spesifikasi thermal-flow teras sama, dan peningkatan EUF dari 63% menjadi 80,14% (untuk RGTT200K dan dari 63,6% menjadi 78,02% (untuk RGTT200KT.

  17. Exfoliative Cheilitis dan Penatalaksanaannya

    Directory of Open Access Journals (Sweden)

    Dewi Agustina

    2012-12-01

    Full Text Available Latar Belakang: Exfoliative cheilitis adalah suatu keadaan inflamatori kronis superfisisal yang ditandai dengan adanya pengelupasan permukaankeratin bibir sedangkan area yang lain terjadi pembentukan lapisan keratin. Tujuan: untuk melaporkan suatu  kasus Exfoliative cheilitis yang diikuti +  selama 2 bulan beserta penatalaksanaanya. Laporan kasus: seorang wanita berusia 52 tahun mengeluh bibir bawahnya pecah-pecah, terasa kering dan panas berdasarkan pemeriksaan subyektif dan klinis, Exfoliative cheilitis ditetapkan sebagai diagnosis kerja. Penatalaksanaanya: Komunikasi-Informasi-Edukasi (KIE diberikan kepada pasien pada awal kunjungan disertai pemberian metil prednisolon, Vitamin B1,6,12 dan anjuran untuk menghentikan kebiasaan menjilat-jilat bibir bawah, menghindari stress dan meningkatkan asupan makanan yang mengandung vitamin A. Pada kunjungna berikutnya pemberian metil prednisolon dihentikan karena terdeteksi adanya peningkatan tekanan darah. Untuk selanjutnya kondisi bibir bawah dievaluasi +  selama 2 bulan. Kesimpulan: Progresitas Exfoliative cheilitis dapat dihentikan dengan bantuan KIE serta menghindari faktor pemicu stress, yang pada akhirnya akan dapat meminimalisir aktivitas factitious berupa menjilat-jilat bibir bawah.    Background: Exfoliative cheilitis is a chronic superficial inflammatory condition that is characterized by regular peeling of a superficial excessive layer of karatin, on the other hand, keratinization is developed in the other area. Aim: to report an Exfoliative cheilitis case monitored for two months and its management. Case Report: a 52 year female has been suffering from fissured lower lip with dry and burning sensations. According to subjective and clinical examinations, Exfoliative cheilitis was determined as the working diagnosis. Management: Communication-Information-Education (CIE were given to the patient at the first visit, besides metyl prednisolon and vitamin B1,6,12 administrations. Patient was

  18. Review of data on irradiation creep of monolithic SiC

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A.; Youngblood, G.E.; Hamilton, M.L. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    An effort is now underway to design an irradiation creep experiment involving SiC composites to SiC fibers. In order to successfully design such an experiment, it is necessary to review and assess the available data for monolithic SiC to establish the possible bounds of creep behavior for the composite. The data available show that monolithic SiC will indeed creep at a higher rate under irradiation compared to that of thermal creep, and surprisingly, it will do so in a temperature-dependant manner that is typical of metals.

  19. New Possibilities of Power Electronic Structures Using SiC Technology

    OpenAIRE

    2006-01-01

    This paper is dedicated to the recent unprecedented boom of SiC electronic technology. The contribution deals with brief survey of those properties. In particular, the differences (both good and bad) between SiC electronics technology and well-known silicon VLSI technology are highlighted. Projected performance benefits of SiC electronics are given for several large-scale applications on the end of the contribution. The basic properties of SiC material have been discussed already on the begin...

  20. Fabrication and Measurements of Hoop Strength of a Multi-Layered SiC Composite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejong; Lee, Jongmin; Kim, Weon Ju; Park, Ji Yeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In this study, the influence of the winding patterns of the SiC fiber on the fiber volume fraction and hoop strength were investigated. Silicon carbide has a low neutron absorption cross section, a high melting point, and low chemical interaction, making it possible to use as fuel cladding in light water reactors. A multi-layered SiC composite tube as the LWR fuel cladding is composed of the monolith SiC inner layer, SiC/SiC composite intermediate layer, and monolith SiC outer layer.

  1. Longitudinal injection of charged particles into a static magnetic configuration with mirrors (1964); Injection longitudinale de particules chargees dans une configuration magnetique statique a miroirs (1964)

    Energy Technology Data Exchange (ETDEWEB)

    Girard, J.P.; Gourdon, C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The theoretical study of the capture of charged particles injected longitudinally into a modulated magnetic configuration of the type proposed by Sinelnikov is extended by the use of the idea of a limited surface. This makes it possible to define the injection conditions which seem to lead to longer confinement times. The injection proposed is effected in the neighbourhood of a trajectory which is asymptotic to equilibrium trajectory situated in the plane of a mirror. Under these conditions the limiting surface is almost completely closed to the mirrors. The initial magnetic moment is no longer zero but has already the maximum value compatible with a penetration of the first mirror. A very small increase in the magnetic moment is then sufficient to ensure the capture of the particles; this is easily attained with a very low modulation factor. It is shown that capture can occur without modulation by a simple non-adiabatic effect due to the curvature of the field in the neighbourhood of the mirrors. A study is made of the influence on the capture in these conditions of a weak parasitic component of the magnetic field which is perpendicular to the axis of revolution of the main configuration. (authors) [French] L'etude theorique de la capture de particules chargees injectees longitudinalement dans une configuration magnetique modulee du type propose par Sinelnikov est etendue par l'utilisation de la notion de surface limite. Ceci permet de definir des conditions d'injections qui semblent devoir conduire a des temps de confinement plus longs: L'injection proposee est faite au voisinage d'une trajectoire asymptote a la trajectoire d'equilibre situee dans le plan d'un miroir. Dans ces conditions la surface limite est presque completement fermee aux miroirs. Le moment magnetique initial n'est plus nul mais possede deja la valeur maximum compatible avec la penetration a travers le premier miroir. Un tres faible accroissement du

  2. Small Incision Cataract Surgery (SICS with Clear Corneal Incision and SICS with Scleral Incision – A Comparative Study

    Directory of Open Access Journals (Sweden)

    Md Shafiqul Alam

    2014-01-01

    Full Text Available Background: Age related cataract is the leading cause of blindness and visual impairment throughout the world. With the advent of microsurgical facilities simple cataract extraction surgery has been replaced by small incision cataract surgery (SICS with posterior chamber intra ocular lens implant, which can be done either with clear corneal incision or scleral incision. Objective: To compare the post operative visual outcome in these two procedures of cataract surgery. Materials and method: This comparative study was carried out in the department of Ophthalmology, Delta Medical College & Hospital, Dhaka, Bangladesh, during the period of January 2010 to December 2012. Total 60 subjects indicated for age related cataract surgery irrespective of sex with the age range of 40-80 years with predefined inclusion and exclusion criteria were enrolled in the study. Subjects were randomly and equally distributed in 2 groups; Group A for SICS with clear corneal incision and group B for SICS with scleral incision. Post operative visual out come was evaluated by determining visual acuity and astigmatism in different occasions and was compared between groups. Statistical analysis was done by SPSS for windows version12. Results: The highest age incidence (43.3% was found between 61 to 70 years of age group. Among study subjects 40 were male and 20 were female. Preoperative visual acuity and astigmatism were evenly distributed between groups. Regarding postoperative unaided visual outcome, 6/12 or better visual acuity was found in 19.98% cases in group A and 39.6% cases in group B at 1st week. At 6th week 6/6 vision was found in 36.3% in Group A and 56.1% in Group B and 46.2% in group A and 66% in group B without and with correction respectively. With refractive correction, 6/6 vision was attained in 60% subjects of group A and 86.67% of group B at 8th week. Post operative visual acuity was statistically significant in all occasions. Postoperative astigmatism of

  3. Singkatan Dan Akronim Dalam Chatting Di Internet

    OpenAIRE

    Hervina M. S.

    2010-01-01

    Penelitian ini menganalis pola singkatan dan akronim dalam chatting di internet. Tujuan penelitian ini adalah mendeskripsikan pola singkatan dan akronim dalam chatting di internet dan mendeskripsikan pola singkatan dan akronim yang paling dominan digunakan dalam chatting di internet. Teori yang digunakan adalah singkatan, akronim, bahasa dalam chatting, sosiolinguistik. Pengumpulan data digunakan dengan metode simak, yaitu penyimakan terhadap penggunaan bahasa (Sudaryanto,1993:133), dan tekni...

  4. LINTASAN SEJARAH FILSAFAT PENDIDIKAN PERENIALISME DAN AKTUALISASINYA

    OpenAIRE

    2015-01-01

    Antara filsafat dan pendidikan terdapat kaitan yang erat. Filsafat memiliki aspek-aspek utama yang dapat dijadikan landasan bagi pendidikan. Aspek-aspek yang dimaksud adalah aspek-aspek metafisis, epistemologis, dan aksiologis. Aspek metafisis antara lain berkaitan dengan persoalan realitas yang tercermin pada bahan ajar, pengalaman dan keterampilan. Aspek epistemologis berkaitan dengan persoalan pengetahuan dan kebenaran, termasuk di dalamnya sumber belajar dan metode pembelajaran. Aspek aks...

  5. Étude préliminaire des pratiques de navigation dans un environnement d’apprentissage informatique et mesure de leur efficacité pédagogique

    Directory of Open Access Journals (Sweden)

    Gilles Lavigne

    2008-01-01

    Full Text Available Inscrite dans une expérience plus vaste centrée sur l’à-propos d’introduire des objets d’apprentissage dans la formation en statistique des étudiants de premier cycle, cette recherche vise plus précisément à étudier l’usage effectif des ressources accessibles dans un environnement informatisé d’apprentissage. L’analyse met en jeu le registre des logs fournis par la plateforme Moodle. Les résultats montrent que l’analyse de la navigation recèle une information à portée pédagogique intéressante, relative à la définition de stratégies d’apprentissage en ligne et à la mesure de l’efficacité pédagogique de ces dernières. Il semble exister, en effet, une relation entre l’intensité d’utilisation des ressources en ligne et la note obtenue à la fin de la formation.

  6. PEMBUATAN DAN KARAKTERISASI ARANG DARI BATANG TANAMAN GUMITIR (Tagetes erecta) PADA BERBAGAI SUHU DAN WAKTU PIROLISIS

    National Research Council Canada - National Science Library

    I Made Siaka; Ni Putu Diana Febriyanti; Emmy Sahara; I Made Sutha Negara

    2017-01-01

    ...) pada berbagai suhu dan waktu pirolisis. Penelitian ini dilakukan untuk memperoleh suhu dan waktu yang optimum dalam pembuatan arang serta mengetahui karakteristik arang yang dihasilkan pada suhu dan waktu optimumnya...

  7. Transport de pétroles bruts lourds sous forme d'émulsion huile dans eau Transporting Heavy Crude Oils in Oil in Water Emulsions

    Directory of Open Access Journals (Sweden)

    Briant J.

    2006-11-01

    Full Text Available Des études préliminaires concernant le comportement visqueux d'émulsions d'un pétrole lourd très visqueux (Boscan, Venezuela dans de l'eau additionnée d'un tensioactif anionique ont été réalisées. Elles montrent que, pour la gamme des vitesses de cisaillement existant dans le transport par oléoduc, des réductions de viscosité de plusieurs ordres de grandeur par rapport à la viscosité du pétrole peuvent être obtenues avec des fractions volumiques de la phase dispersée de l'ordre de 60 %. This article describes a preliminary research on the viscous behavior of emulsions of a highly viscous heavy crude oil (Boscan, Venezuela in water containing an anionic surfactant. In the range of the shear rates usually encountered in pipelines, it is shown that the viscosity can be reduced by several orders of magnitude as compared with the crude oil viscosity, and th is for volume fractions of the dispersed phase in the range of 60%.

  8. RESISTENSI AGAMA DAN BUDAYA MASYARAKAT

    Directory of Open Access Journals (Sweden)

    David Samiyono

    2013-12-01

    Interaksi antar etnis, agama dan budaya bukanlah barang langka di Bali. Sejak semula hal tersebut sudah ada, ketika pulau ini menjadi locus perdagangan hasil bumi. Sebab sesungguhnya kebudayaan Bali menjujung tinggi nilai-nilai keseimbangan dan harmonisasi antar manusia dengan Tuhan (perhyangan, dengan sesama (pawongan dan dengan lingkungan (palemahan. Konsep ini disebut Tri hita karana. Bali kini berubah. Budayanya berorientasi pada jasa, yang berkait dengan industri pariwisata. Sikap orang Bali kini tidak lagi ramah dan harmoni. Akibat ledakan bom dalam bulan Oktober 2002 dan 2005, masyarakat lebih berhati-hati terhadap para pendatang. Ajeg Bali merupakan kearifan lokal –agama dan budaya– masyarakat Bali dalam rangka menanggulangi pengaruh luar yang mengakibatkan perubahan di berbagai bidang sehingga identitas kebalian mengalami degradasi. Ajeg Bali merupakan bentuk resistensi masyar­akat Bali dalam rangka membatasi pendatang dari luar Bali. Kajian ini berusaha untuk menjawab pertanyaan “apakah Ajeg Bali, sebuah kearifan lokal masyarakat Bali dapat membendung pengaruh budaya, agama dan ekonomi masyarakat Bali?”

  9. The effect of structural defects in SiC particles on the static & dynamic mechanical response of a 15 volume percent SiC/6061-Al matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, R.U.; Song, S.G.; Zurek, A.K.; Gray, G.T. III

    1995-09-01

    Static and Dynamic mechanical tests, and microstructural examinations performed on a SiC particle reinforced 6061-Al matrix composite indicated that particle cracking significantly affected the strength, strain hardening, and failure mechanism of the composite. Cracks were observed to nucleate and propagate on stacking faults and interfaces between the various phases within the reinforcing SiC particles. Planar defects were the predominant artifacts seen in the SiC particles. Partial dislocations were also observed bounding the stacking faults within the reinforcement phase.

  10. Low Activation Joining of SiC/SiC Composites for Fusion Applications: Modeling Thermal and Irradiation-induced Swelling Effects on Integrity of Ti3SiC2/SiC Joint

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.; Ferraris, M.; Katoh, Yutai

    2017-03-31

    This work developed a continuum damage mechanics model that incorporates thermal expansion combined with irradiation-induced swelling effects to study the origin of cracking observed in recent irradiation experiments. Micromechanical modeling using an Eshelby-Mori-Tanaka approach was used to compute the thermoelastic properties of the Ti3SiC2/SiC joint needed for the model. In addition, a microstructural dual-phase Ti3SiC2/SiC model was developed to determine irradiation-induced swelling of the composite joint at a given temperature resulting from differential swelling of SiC and the Ti3SiC2 MAX phase. Three cases for the miniature torsion hourglass (THG) specimens containing a Ti3SiC2/SiC joint were analyzed corresponding to three irradiation temperatures: 800oC, 500oC, and 400oC.

  11. Kitab kuning dan perempuan, perempuan dan kitab kuning

    NARCIS (Netherlands)

    Bruinessen, M.M. van

    2007-01-01

    Kitab Kuning dan Emansipasi Perempuan: Konflik Budaya? Pengamatan-pengamatan Masdar mengenai kedudukan perempuan dalam diskursus (wacana, bahasan) dominan kitab kuning terasa tidak enak didengar tetapi memang sulit dibantah. Baik dalam penggunaan bahasa (yang sangat memihak kepada jenis mudzakkar) m

  12. Feasibility study of a SiC sandwich neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian, E-mail: caepwujian@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Lei, Jiarong, E-mail: jiarong_lei@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Jiang, Yong; Chen, Yu; Rong, Ru; Zou, Dehui; Fan, Xiaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Chen, Gang; Li, Li; Bai, Song [Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2013-04-21

    Semiconductor sandwich neutron spectrometers are suitable for in-pile measurements of fast reactor spectra thanks to their compact and relatively simple design. We have assembled and tested a sandwich neutron spectrometer based on 4H-silicon carbide (4H-SiC) Schottky diodes. The SiC diodes detect neutrons via neutron-induced charged particles (tritons and alpha particles) produced by {sup 6}Li(n,α){sup 3}H reaction. {sup 6}LiF neutron converter layers are deposited on the front surface of Schottky diodes by magnetron sputtering. The responses of SiC diodes to charged particles were investigated with an {sup 241}Am alpha source. A sandwich neutron spectrometer was assembled with two SiC Schottky diodes selected based on the charged-particle-response experimental results. The low-energy neutron response of the sandwich spectrometer was measured in the neutron field of the Chinese Fast Burst Reactor-II (CFBR-II). Spectra of alpha particles and tritons from {sup 6}Li(n,α){sup 3}H reaction were obtained with two well-resolved peaks. The energy resolution of the sum spectrum was 8.8%. The primary experimental results confirmed the 4H-SiC sandwich neutron spectrometer's feasibility. -- Highlights: ► Sandwich neutron spectrometer employing 4H-SiC as a detecting material has been developed for the first time. ► {sup 6}LiF neutron converter has been deposited on the surface of 4H-SiC Schottky diode. ► Preliminary testing results obtained with the 4H-SiC sandwich neutron spectrometer are presented.

  13. Perancangan dan Analisis Redistribution Routing Protocol OSPF dan EIGRP

    Directory of Open Access Journals (Sweden)

    DWI ARYANTA

    2016-02-01

    Full Text Available Abstrak OSPF (Open Shortest Path First dan EIGRP (Enhanced Interior Gateway Routing Protocol adalah dua routing protokol yang banyak digunakan dalam jaringan komputer. Perbedaan karakteristik antar routing protokol menimbulkan masalah dalam pengiriman paket data. Teknik redistribution adalah solusi untuk melakukan komunikasi antar routing protokol. Dengan menggunakan software Cisco Packet Tracer 5.3 pada penelitian ini dibuat simulasi OSPF dan EIGRP yang dihubungkan oleh teknik redistribution, kemudian dibandingkan kualitasnya dengan single routing protokol EIGRP dan OSPF. Parameter pengujian dalam penelitian ini adalah nilai time delay dan trace route. Nilai trace route berdasarkan perhitungan langsung cost dan metric dibandingkan dengan hasil simulasi. Hasilnya dapat dilakukan proses redistribution OSPF dan EIGRP. Nilai delay redistribution lebih baik 1% dibanding OSPF dan 2-3% di bawah EIGRP tergantung kepadatan traffic. Dalam perhitungan trace route redistribution dilakukan 2 perhitungan, yaitu cost untuk area OSPF dan metric pada area EIGRP. Pengambilan jalur utama dan alternatif pengiriman paket berdasarkan nilai cost dan metric yang terkecil, hal ini terbukti berdasarkan perhitungan dan simulasi. Kata kunci: OSPF, EIGRP, Redistribution, Delay, Cost, Metric. Abstract OSPF (Open Shortest Path First and EIGRP (Enhanced Interior Gateway Routing Protocol are two routing protocols are widely used in computer networks. Differences between the characteristics of routing protocols pose a problem in the delivery of data packets. Redistribution technique is the solution for communication between routing protocols. By using the software Cisco Packet Tracer 5.3 in this study were made simulating OSPF and EIGRP redistribution linked by technique, then compared its quality with a single EIGRP and OSPF routing protocols. Testing parameters in this study is the value of the time delay and trace route. Value trace route based on direct calculation of cost

  14. Réduction de l'oxyde d'azote par la suie dans les produits de combustion Reduction of Nitric Oxyde by Soot in Combustion Products

    Directory of Open Access Journals (Sweden)

    De Soete G.

    2006-11-01

    Full Text Available On a étudié dans un réacteur à lit fixe la réduction du NO par de la suie formée dans des flammes riches de mélanges éthane/oxygène/argon. Le mélange gazeux traversant le réacteur est de l'argon dopé avec du NO; dans certains cas ce mélange est enrichi d'hydrogène ou d'oxyde de carbone. En présence d'hydrogène ou d'oxyde de carbone, ces vitesses sont nettement plus grandes qu'avec la suie seule. La comparaison avec des vitesses réactionnelles obtenues sur des lits fixes composés d'autres matériaux solides, tels que l'alumine, montre que la réduction de l'oxyde d'azote se fait principalement par une réaction hétérogène avec l'hydrogène et l'oxyde de carbone catalysée par la suie. D'autres matériaux solides,tels que des oxydes réfractaires présentent une activité catalylique aussi importante que la suie. Cette observation fournit une nouvelle explication de l'effet connu de certains additifs sur la réduction de NO dans les flammes. Dans la seconde partie de l'étude, on mesure la réduction des oxydes d'azote dans les flammes fuligineuses de prémélange. De l'argon dopé par de l'oxyde d'azote est injecté dans les produits de combustion de ces flammes chargés de suie; l'introduction du NO est faite à différentes distances derrière le brûleur, correspondant à différents niveaux de température des produits de combustion. La réduction fractionnelle des oxydes d'azote est mesurée en fonction de la concentration en suie, en hydrogène et en oxyde de carbone, en faisant varier la composition du mélange inflammable. Les résultats expérimentaux sont en bon accord avec la réduction calculée en se basant sur les informations cinétiques obtenues en lit fixe. The kinetics of nitric oxide réduction by soot collected from hydrocarbon flames is studied in a fixed-bed reactor. The gas flow traversing thé reactor is either argon with NO, or argon with hydrogen and NO, or argon with carbon monoxide and NO. In th

  15. Perawatan Pergeseran Mandibula dan Kliking Menggunakan Teknik Edgewise dan Trainer

    Directory of Open Access Journals (Sweden)

    Rully Utami

    2014-06-01

    Full Text Available Kasus ini terjadi pada perempuan usia 22 tahun yang bersedia dipublikasikan untuk kepentingan  ilmu pengetahuan. Keluhan utama mandibula dan dagunya bergeser ke kanan, gigitan terbuka posterior dan bunyi click di persendian temporomandibular. Diagnosis pasien adalah maloklusi Angle kelas III tipe dento skeletal, pergeseran garis tengah mandibula dan dagu ke kanan, gigitan terbuka posterior dan clicking pada sendi temporomandibular. Perawatan dilakukan dengan teknik Edgewise dan trainer. Leveling dan unraveling dilakukan menggunakan kawat stainless steel bulat diameter 0,014 mm dengan multiloop. Trainer digunakan untuk koreksi pergeseran mandibula. Perawatan dilakukan selama 11 bulan, dan menunjukkan hasil hubungan molar pertama kanan menjadi kelas I. Overjet meningkat dari 0,1 mm menjadi 2 mm, overbite meningkat dari 0,2 mm menjadi 2,57 mm, garis tengah mandibula yang semula bergeser ke kanan 4,38 mm menjadi 2,53 mm, gigitan terbuka posterior dan clicking telah terkoreksi. Compromised Treatment of Class III Malocclusion with Mandibular Shifting, Posterior Openbite and Clicking Using Edgewise Technique and Trainer In Adult. This case report described the treatment of an adult female 22 years old who complained that her mandibula and chin shift to the right, posterior openbite and clicking. The patient diagnosed class III molar relationship, skeletal class III malocclusion, mandibular midline and chin shift to the right, posterior openbite and clicking on temporomandibular joint. Treatment was conducted using combination between  Edgewise Technique and trainer.  Leveling and unraveling are achieved by round stainless steel archwire 0,014 mm with multiloop. Trainer used to corrected the mandibular shifting. Result after 1 years treatment showed that the right molar relationship became class I, overjet increased  from 0,1 mm to 2 mm, overbite increased  from 0,2 mm to 2,57 mm, mandibular midline shifting decresed from 4,38 mm to 2,53 mm

  16. Ultra High Temperature (UHT) SiC Fiber (Phase 2)

    Science.gov (United States)

    Dicarlo, James A.; Jacobson, Nathan S.; Lizcano, Maricela; Bhatt, Ramakrishna T.

    2015-01-01

    Silicon-carbide fiber-reinforced silicon-carbide ceramic matrix composites (SiCSiC CMC) are emerginglightweight re-usable structural materials not only for hot section components in gas turbine engines, but also for controlsurfaces and leading edges of reusable hypersonic vehicles as well as for nuclear propulsion and reactor components. Ithas been shown that when these CMC are employed in engine hot-section components, the higher the upper usetemperature (UUT) of the SiC fiber, the more performance benefits are accrued, such as higher operating temperatures,reduced component cooling air, reduced fuel consumption, and reduced emissions. The first generation of SiCSiC CMC with a temperature capability of 2200-2400F are on the verge of being introduced into the hot-section components ofcommercial and military gas turbine engines.Today the SiC fiber type currently recognized as the worlds best in terms ofthermo-mechanical performance is the Sylramic-iBN fiber. This fiber was previously developed by the PI at NASA GRC using patented processes to improve the high-cost commercial Sylramic fiber, which in turn was derived from anotherlow-cost low-performance commercial fiber. Although the Sylramic-iBN fiber shows state-of-the art creep and rupture resistance for use temperatures above 2550oF, NASA has shown by fundamental creep studies and model developmentthat its microstructure and creep resistance could theoretically be significantly improved to produce an Ultra HighTemperature (UHT) SiC fiber.This Phase II Seedling Fund effort has been focused on the key objective of effectively repeating the similar processes used for producing the Sylramic-iBN fiber using a design of experiments approach to first understand the cause of the less than optimum Sylramic-iBN microstructure and then attempting to develop processconditions that eliminate or minimize these key microstructural issues. In so doing, it is predicted that that theseadvanced process could result in an UHT SiC

  17. Silicon assistant carbothermal reduction for SiC powders

    Institute of Scientific and Technical Information of China (English)

    Kezhi Li; Jian Wei; Hejun Li; Chuang Wang; Gengsheng Jiao

    2008-01-01

    The silicon assistant method to increase the reaction yield of carbothermal reduction of silica at a lower temperature is reported. The effect of silicon on the carbothermal reduction process has been investigated in detail. Compared with traditional reduction, the introduction of silicon can change the reaction path and further increase the conversion of silicon carbide at a lower temperature. It is considered that the assistant reduction consists of three steps: vaporizing and melting of silicon, formation of silicon monoxide, and synthesis of silicon carbide. The morphology of the synthesized SiC powders through the silicon assistant method can be affected apparently by the experimental temperature.

  18. Construction Progress of the S-IC Test Stand

    Science.gov (United States)

    1961-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photo shows the construction progress of the test stand as of August 14, 1961. Water gushing in from the disturbance of a natural spring contributed to constant water problems during the construction process. It was necessary to pump water from the site on a daily basis and is still pumped from the site today. The equipment is partially submerged in the water emerging from the spring.

  19. Estimation des contraintes électrothermiques sur les composants semi-conducteurs dans les onduleurs photovoltaïques

    OpenAIRE

    Dbeiss, Mouhannad; Avenas, Yvan; ZARA, Henri

    2016-01-01

    International audience; Cet article présente une étude comparative entre les MOSFETs en SiC et les IGBTs en Si vis-à-vis des variations de leur température de jonction dans une application d'onduleur photovoltaïque. L'estimation de ces variations est faite en introduisant dans un modèle de calcul, des profils de mission en courant extraits d'une centrale photovoltaïque sur une année entière. Les résultats sont les profils de mission de la température de jonction des semi-conducteurs, qui perm...

  20. KONSEP DAN PRAKTIK PENDIDIKAN MULTIKULTURAL DI AMERIKA SERIKAT DAN INDONESIA

    Directory of Open Access Journals (Sweden)

    Juju Masunah

    2011-11-01

    Full Text Available Abstract: Concepts and Practices of Multi Cultural Education in the United States and in Indonesia. The purpose of this article is to discuss multicultural education consepts and practices in the U.S.A and its application to Indonesia. Data is based on a case study research of two dance educators who implemented multicultural education concept in Columbus, Ohio in year 2007. The result of this research is that two dance educators teach students equally by developing a curriculum and pedagogy that face democracy for all students. This concept and practice is possible to be applied to dance education in Indonesia. Abstrak: Konsep dan Praktik Pendidikan Multikultural di Amerika Serikat dan Indonesia. Tujuan artikel ini adalah untuk mendiskusikan konsep dan praktik pendidikan multikultural di Amerika Serikat dan Indonesia. Data-data diperoleh dari hasil penelitian studi kasus dua orang pendidik tari di Columbus, Ohio yang menerapkan konsep pendidikan multikultural dalam pembelajaran tari pada tahun 2007. Peneli­tian ini menyimpulkan bahwa dua guru tari tersebut memberi perlakuan yang sama dan adil terhadap se­mua siswa dengan cara yang demokratis dengan memperhatikan keberagaman dan keperbedaan siswa. Cara-cara ini sangat memungkinkan untuk diaplikasikan dalam pendidikan tari di Indonesia.

  1. 10kV SiC MOSFET split output power module

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Li, Helong; Uhrenfeldt, Christian

    2015-01-01

    The poor body diode performance of the first generation of 10kV SiC MOSFETs and the parasitic turn-on phenomenon limit the performance of SiC based converters. Both these problems can potentially be mitigated using a split output topology. In this paper we present a comparison between a classical...

  2. Control of SiC Based Front-End Rectifier under Unbalanced Supply Voltage

    DEFF Research Database (Denmark)

    Maheshwari, Ramkrishan; Trintis, Ionut; Gohil, Ghanshyamsinh Vijaysinh

    2015-01-01

    A voltage source converter is used as a front end converter typically. In this paper, a converter which is realized using SiC MOSFET is considered. Due to SiC MOSFET, a switching frequency more than 50 kHz can be achieved. This can help increasing the current control loop bandwidth, which...

  3. Characterisation of 10 kV 10 A SiC MOSFET

    DEFF Research Database (Denmark)

    Eni, Emanuel-Petre; Incau, Bogdan Ioan; Munk-Nielsen, Stig

    2015-01-01

    The objective of this paper is to characterize and evaluate the static and dynamic performances of 10 kV 10 A 4H-SIC MOSFETs at high temperatures. The results show good electrical performances of the SiC MOSFETs for high temperature operations. The double-pulse test results showed interesting...

  4. Using of the Modern Semiconductor Devices Based on the SiC

    Directory of Open Access Journals (Sweden)

    Pavel Drabek

    2008-01-01

    Full Text Available This paper deals with possibility of application of the semiconductor devices based on the SiC (Silicon Carbide inthe power electronics. Basic synopsis of SiC based materials problems are presented, appreciation of their properties incomparison with current using power semiconductor devices ((IGBT, MOSFET, CoolFET transistors.

  5. A Short-Circuit Safe Operation Area Identification Criterion for SiC MOSFET Power Modules

    DEFF Research Database (Denmark)

    Reigosa, Paula Diaz; Iannuzzo, Francesco; Luo, Haoze

    2017-01-01

    to the experimental results, two different failure mechanisms have been identified, both reducing the short-circuit capability of SiC power modules with respect to discrete SiC devices. Based on such failure mechanisms, two short-circuit safety criteria have been formulated: 1) the short...

  6. Synthesis of SiC from rice husk in a plasma reactor

    Indian Academy of Sciences (India)

    S K Singh; B C Mohanty; S Basu

    2002-11-01

    A new route for production of SiC from rice husk is reported by employing thermal plasma technique. The formation of -SiC is observed in a short time of 5 min. The samples are characterized by XRD and SEM.

  7. Development of Simulink-Based SiC MOSFET Modeling Platform for Series Connected Devices

    DEFF Research Database (Denmark)

    Tsolaridis, Georgios; Ilves, Kalle; Reigosa, Paula Diaz

    2016-01-01

    A new MATLAB/Simulink-based modeling platform has been developed for SiC MOSFET power modules. The modeling platform describes the electrical behavior f a single 1.2 kV/ 350 A SiC MOSFET power module, as well as the series connection of two of them. A fast parameter initialization is followed...

  8. Deposition of thin ultrafiltration membranes on commercial SiC microfiltration tubes

    DEFF Research Database (Denmark)

    Facciotti, Marco; Boffa, Vittorio; Magnacca, Giuliana;

    2014-01-01

    Porous SiC based materials present high mechanical, chemical and thermal robustness, and thus have been largely applied to water-filtration technologies. In this study, commercial SiC microfiltration tubes with nominal pore size of 0.04 m were used as carrier for depositing thin aluminium oxide...

  9. The effect of Cs{sup +} ions on codeposition of SiC particles with nickel

    Energy Technology Data Exchange (ETDEWEB)

    Rudnik, Ewa, E-mail: erudnik@agh.edu.pl [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, Laboratory of Physical Chemistry and Electrochemistry, Al. Mickiewicza 30, 30-059 Cracow (Poland); Burzynska, Lidia; Gut, Marcin [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, Laboratory of Physical Chemistry and Electrochemistry, Al. Mickiewicza 30, 30-059 Cracow (Poland)

    2011-04-15

    Research highlights: {yields} The papers describes electrodeposition of SiC particles with nickel matrix in the presence of cesium ions. {yields} Correlations among the Cs{sup +} concentration in the bath, kinetics of the cathodic process, SiC content in the deposits as well as adsorption of Ni{sup 2+} ions on SiC were found. {yields} Microhardness of the Ni/SiC deposits was also determined. - Abstract: Electrodeposition of SiC particles (technical powder) with nickel matrix in the presence of cesium ions (0-37.6 mM) was investigated. The influence of Cs{sup +} concentration on cathodic polarization curves was determined in galvanostatic and potentiodynamic measurements. The presence of Cs{sup +} in the solution enhanced in some extent adsorption of Ni{sup 2+} ions on SiC, but preferential cesium adsorption occurred simultaneously. The last phenomenon resulted in cesium incorporation in the composite coating. The particle content in the deposits (16-24 vol%) was governed by the amount of nickel ions adsorbed on SiC. Structure of the composite coatings was studied by microscopic observations. At highest Cs{sup +} concentrations, incorporation of small SiC grains was inhibited. Microhardness of deposits (390-800 HV) was directly dependent on the SiC content in the coatings.

  10. Broadband Antireflection and Light Extraction Enhancement in Fluorescent SiC with Nanodome Structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Zhu, Xiaolong; Jokubavicius, Valdas

    2014-01-01

    We demonstrate a time-efficient and low-cost approach to fabricate Si3N4 coated nanodome structures in fluorescent SiC. Nanosphere lithography is used as the nanopatterning method and SiC nanodome structures with Si3N4 coating are formed via dry etching and thin film deposition process. By using...

  11. MAX Phase Modified SiC Composites for Ceramic-Metal Hybrid Cladding Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang-Il; Kim, Sun-Han; Park, Dong-Jun; Park, Jeong-Hwan; Park, Jeong-Yong; Kim, Hyun-Gil; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    A metal-ceramic hybrid cladding consists of an inner zirconium tube, and an outer SiC fiber-matrix SiC ceramic composite with surface coating as shown in Fig. 1 (left-hand side). The inner zirconium allows the matrix to remain fully sealed even if the ceramic matrix cracks through. The outer SiC composite can increase the safety margin by taking the merits of the SiC itself. In addition, the outermost layer prevents the dissolution of SiC during normal operation. On the other hand, a ceramic-metal hybrid cladding consists of an outer zirconium tube, and an inner SiC ceramic composite as shown in Fig. 1 (right-hand side). The outer zirconium protects the fuel rod from a corrosion during reactor operation, as in the present fuel claddings. The inner SiC composite, additionally, is designed to resist the severe oxidation under a postulated accident condition of a high-temperature steam environment. Reaction-bonded SiC was fabricated by modifying the matrix as the MAX phase. The formation of Ti{sub 3}SiC{sub 2} was investigated depending on the compositions of the preform and melt. In most cases, TiSi{sub 2} was the preferential phase because of its lowest melting point in the Ti-Si-C system. The evidence of Ti{sub 3}SiC{sub 2} was the connection with the pressurizing.

  12. Tribo-mechanical behaviour of SiC filled glass-epoxy composites at ...

    African Journals Online (AJOL)

    Tribo-mechanical behaviour of SiC filled glass-epoxy composites at elevated temperatures. ... Username, Password, Remember me, or Register ... For instance, the introduction of ceramics such (SiC, Al2O3, TiC, etc.) as within the matrix ...

  13. Development of nanoporous TiO2 and SiC membranes for membrane filtration

    DEFF Research Database (Denmark)

    König, Katja; Vigna, Erika; Farsi, Ali

    reverse osmosis membranes by ceramic counterparts would provide higher fluxes and allow more efficient cleaning of the membranes. The aim of this work was to prepare defect-free nanoporous ceramic (TiO2 and SiC) layers on macroporous SiC supports by using electrophoretic deposition and dip...

  14. RADIKALISME NEGARA DAN KEKUASAAN PERSPEKTIF POLITIK GLOBAL

    Directory of Open Access Journals (Sweden)

    M. Sidi Ritaudin

    2014-12-01

    Full Text Available Meskipun tragedi kemanusiaan yang berbasis terorisme bersifat domistik regional, tetapi sebab musababnya, setelah dilakukan penelusuran secara kritis dan tajam serta mendalam oleh para ahli, adalah dimensi politik global. Ini bukan asumsi tetapi fakta dan realita. Sebut saja misalnya tragedi WTC di Amerika serikat 11 September 2001, yang berbuntut pada pembumihangusan Irak, pembantaian dan pembunuhan secara keji di Palestina. Dan saat ini terjadi pembumihangusan Irak jilid dua dengan peristiwa ISIS, tragedi kemanusiaan di Ukraina dan Somalia. Sebahagian pemerhati Islam dan Timur Tengah menengarai bahwa motif gerakan radikalisme merupakan antitesa dari keserakahan politik, ekonomi, kekuasaan dan keangkuhan peradaban. Paradoksal radikalisme Islam dengan para aktivis pengusung ide sekularisme, pluralisme, dan liberalisme agama sudah berlangsung cukup lama dan tiada berkesudahan, menarik untuk didiskusikan.

  15. CORPORATE IDENTITY SEJARAH DAN APLIKASINYA

    Directory of Open Access Journals (Sweden)

    Christine Suharto Cenadi

    1999-01-01

    Full Text Available In the recent globalization era%2C and the developed market%2C many companies compete to attract consumers to buy their products. One of the keys to compete and survive in this developing market is by creating an image and graphic identity. This paper will discuss about corporate identity%2C image%2C its purpose and applications. Abstract in Bahasa Indonesia : Dalam era globalisasi dewasa ini%2C dan dengan berkembangnya pasar (market%2C banyak perusahaan bersaing untuk menarik perhatian konsumen untuk membeli produknya. Salah satu cara untuk bersaing dan dapat bertahan di dalam pasar yang terus berkembang ini adalah dengan menciptakan suatu image dan identitas graphic. Tulisan ini akan membahas tentang corporate identity%2C image%2C fungsi dan aplikasinya

  16. ETUDE DU COMPORTEMENT MECANIQUE DES ACIERS HYPEREUTECTOIDES DANS LE DOMAINE DE TEMPERATURE INTERCRITIQUE DYNAMIQUE

    Directory of Open Access Journals (Sweden)

    R GHERIANI

    2001-06-01

    Full Text Available L'étude que nous présentons contribue à une meilleure compréhension de l'influence de la vitesse de déformation et de la température sur le comportement mécanique des aciers hypereutectoïdes dans le domaine de température intercritique dynamique. Les courbes expérimentales obtenues en torsion présentent un intérêt notable dans la mesure où elles permettent de caractériser le comportement mécanique de l'acier 100C6; de plus, elles fournissent  des informations précieuses sur la capacité maximale de déformation de l'alliage. Les essais de torsion, menés jusqu'à rupture des éprouvettes, permettent d'effectuer un classement des matériaux selon leur ductilité. Les résultats obtenus sur l'acier 100C6 ont permis de préciser le comportement mécanique à tiède  de cet acier. Les aciers hypoeutectoïdes présentent, dans les domaines de température compris entre Ac1 et Ac3 en condition dynamique, une capacité de déformation élevée résultant de l'évolution, en cours de déformation, des phases a et g et de leurs mécanismes d'adoucissement. Nous nous sommes alors posé la question: quel est le comportement d'un acier hypereutectoïde, donc ne présentant  pas de domaine biphasé (a + g à l'équilibre, lorsqu'il est déformé à une température supérieure à Ac1?

  17. Synthesis of Freestanding Graphene on SiC by a Rapid-Cooling Technique

    Science.gov (United States)

    Bao, Jianfeng; Norimatsu, Wataru; Iwata, Hiroshi; Matsuda, Keita; Ito, Takahiro; Kusunoki, Michiko

    2016-11-01

    Graphene has a negative thermal expansion coefficient; that is, when heated, the graphene lattice shrinks. On the other hand, the substrates typically used for graphene growth, such as silicon carbide, have a positive thermal expansion coefficient. Hence, on cooling graphene on SiC, graphene expands but SiC shrinks. This mismatch will physically break the atomic bonds between graphene and SiC. We have demonstrated that a graphenelike buffer layer on SiC can be converted to a quasifreestanding monolayer graphene by a rapid-cooling treatment. The decoupling of graphene from the SiC substrate was actually effective for reducing the electric carrier scattering due to interfacial phonons. In addition, the rapidly cooled graphene obtained in this way was of high-quality, strain-free, thermally stable, and strongly hole doped. This simple, classical, but quite novel technique for obtaining quasifreestanding graphene could open a new path towards a viable graphene-based semiconductor industry.

  18. A Novel SiC Foam Valve Tray for Distillation Columns

    Institute of Scientific and Technical Information of China (English)

    张吕鸿; 刘学宽; 李鑫钢; 高鑫; 隋红; 张劲松; 杨振明; 田冲; 李洪

    2013-01-01

    The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surface area. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquid height. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Compared with the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70%lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, the overall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.

  19. Preparation of Ti3SiC2 with Aluminum by Means of Spark Plasma Sintering

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Polycrystalline bulk Ti3SiC2 material with a high purity and density was fabricated by spark plasma sintering from the elemental powder mixture with starting composition of Ti3Si1-xAlxC2,where x=0.05-0.2.X-ray diffraction patterns and scanning electron microscopy photographs of the fully dense samples show that a proper addition of aluminum promotes the formation,and accelerates the crystal growth rate of Ti3SiC2,consequently results in a high purity of the prepared samples.The synthesized Ti3SiC2 is in plane-shape with a size of about 10-25μm in the elongated dimension.Solid solution of aluminum decreases the thermal stability of Ti3SiC2,and lowers the temperature of Ti3SiC2 decomposeing to be 1300 ℃.

  20. Memahami Patofisiologi dan Aspek Klinis Syok Hipovolemik: Update dan Penyegar

    Directory of Open Access Journals (Sweden)

    Hardisman Hardisman

    2013-09-01

    Full Text Available AbstrakSecara patofisiologis syok merupakan gangguan hemodinamik yang menyebabkan tidak adekuatnya hantaran oksigen dan perfusi jaringan. Gangguan hemodinamik tersebut dapat berupa penurunan tahanan vaskuler sitemik terutama di arteri, berkurangnya darah balik, penurunan pengisian ventrikel dan sangat kecilnya curah jantung. Gangguan faktor-faktor tersebut disbabkan oleh bermacam-macam proses baik primer pada sistim kardiovaskuler, neurologis ataupun imunologis. Diantara berbagai penyebab syok tersebut, penurunan hebat volume plasma intravaskuler merupakan faktor penyebab utama. Terjadinya penurunan hebat volume intravaskuler dapat terjadi akibat perdarahan atau dehidrasi berat, sehingga menyebabkan yang balik ke jantung berkurang dan curah jantungpun menurun. Penurunan hebat curah jantung menyebabkan hantaran oksigen dan perfusi jaringan tidak optimal dan akhirnya menyebabkan syok. Pada tahap awal dengan perdarahan kurang dari 10%, gejala klinis dapat belum terlihat karena adanya mekanisme kompensasi sisitim kardiovaskuler dan saraf otonom. Baru pada kehilangan darah mulai 15% gejala dan tanda klinis mulai terlihat berupa peningkatan frekuensi nafas, jantung atau nadi (takikardi, pengisian nadi yang lemah, penurunan tekanan nadi, kulit pucat dan dingin, pengisian kapiler yang lambat dan produksi urin berkurang. Perubahan tekanan darah sistolik lebih lambat terjadi akibat adanya mekanisme kompensasi tadi, sehingga pemeriksaan klinis yang seksama harus dilakukan.Kata kunci: syok, hipovolemik dan patofisiologiAbstractShock is hemodynamic disorders, which causes inadequate oxygen delivery and perfusion. The hemodynamic disorders can be decreasing of systemic vascular resistant, venous return, ventricular filling and inadequate of cardiac output. The disorders are caused by cardiovascular dysfunction, neurologic or immunologic factors. Intravascular volume loss is one of the main factors, which is caused by severe dehydration or bleeding. These

  1. Sifilis Laten: Diagnosis dan Pengobatan

    Directory of Open Access Journals (Sweden)

    Rasmia Rowawi

    2013-09-01

    Full Text Available Abstrak   Sifilis laten merupakan stadium sifilis yang diakibatkan oleh T. pallidum yang masih menetap dalam tubuh, namun tidak menunjukkan gejala dan hanya menunjukkan hasil pemeriksaan serologis yang reaktif. Sifilis laten yang tidak diterapi dapat menetap bertahun-tahun atau seumur hidup dan dapat meningkatkan risiko terinfeksi HIV. Ibu hamil dengan sifilis laten dini akan menyebabkan sekitar 40% bayi yang dilahirkankannya tertular, 20% prematur, 10% lahir mati, dan 4% meninggal pada waktu dilahirkan. Diagnosis sifilis laten dini ditegakkan bila dalam 12 bulan terakhir ditemukan satu atau lebih dari tanda-tanda berikut ini: peningkatan titer VDRL/RPR sebanyak empat kali atau lebih; pada anamnesis didapatkan gejala sifilis primer dan sekunder; riwayat kontak seksual dengan seseorang yang didiagnosis atau diduga menderita sifilis primer atau sifilis sekunder atau sifilis laten dini; serta kontak seksual dengan seseorang dengan tes VDRL atau RPR dan TPHA reaktif. Pengobatan yang direkomendasikan untuk sifilis laten dini adalah benzatin penisilin 2,4 juta UI, IM, dosis tunggal, sedangkan pada sifilis laten lanjut, benzatin penisilin 2,4 juta UI, IM, diberikan 3 kali dengan interval satu minggu. Pemeriksaan serologis sifilis non- treponemal (VDRL atau RPR dilakukan setelah pengobatan 3, 6, 12, dan 24 bulan untuk menilai keberhasilan pengobatan.   Kata kunci: Diagnosis, silifis laten, terapi

  2. EXIGENCES TECHNIQUES DANS LA CONSTRUCTION ET REGLEMENTATION : ETUDE D’UN EXEMPLE DE LOGEMENT COLLECTIF A AIN-SMARA (ALGERIE

    Directory of Open Access Journals (Sweden)

    B BENRACHI

    2002-12-01

    Full Text Available La construction d’un édifice de qualité standard et répondant aux exigences techniques est   obtenue grâce au développement du savoir-faire et au respect des règles de l’art et de la réglementation en vigueur.  Une étude détaillée sur les  exigences techniques et le respect de la réglementation  d’un logement en collectif  nouvellement construit et inhabité à Ain-Smara, nous a montré  qu’il y a une satisfaction pour certaines d'entre-elles et une non-conformité pour d’autres. Il en résulte que le degré de satisfaction de ce logement est inférieur à celui recommandé dans le cadre de la réglementation, ce qui diminue sa qualité par rapport au standard exigé.

  3. Coating of SiC Powder with Nano YAG Phase

    Institute of Scientific and Technical Information of China (English)

    Zhang Ning; Cai Qingkui; Ru Hongqiang; Li Ying; Qiu Guanming; Sun Xudong

    2005-01-01

    SiC-YAG(Y3Al5O12) ceramic composite powders were prepared by co-precipitation coating method. Mechanism of co-precipitation coating of SiC powders with Y3+ and Al3+ precursors was investigated. If the concentration of [OH-] ion in the solution is controlled within the range between critical values for heterogeneous nucleation and homogeneous nucleation, Y3+ and Al3+ precipitation precursors can be coated on the surface of SiC particles. Y3+ and Al3+ precipitation precursors transform into YAG phase after calcining at 1000 ℃ without the formation of YAM and YAP phases. The formation temperature of YAG phase is about 600 ℃ lower than that of conventional powder mixing method. The effect of pH value of the solution and precipitant titration rate on coating quality of SiC-YAG composite powders was also studied. The results show that co-precipitation coating can be realized at a final pH of 9 and a precipitant titration rate of 5 ml·min-1.

  4. Crystal growth and characterization of fluorescent SiC

    DEFF Research Database (Denmark)

    Wellmann, P.; Kaiser, M.; Hupfer, T.

    of the phosphorous into the SiC substrate to make an all semiconductor white LED. In recent years, due to the improvement of the crystalline quality of SiC by the so called fast sublimation growth process (FSGP), high room temperature internal quantum efficiencies of the yellow donor acceptor pair luminescence of 6H......-SiC co-doped with nitrogen and boron has been achieved [1][2]. The source is the rate determining step, and is expected to be determining the fluorescent properties by introducing dopants to the layer from the source. The optimization process of the polycrystalline, co-doped SiC:B,N source material...... and its impact on the FSPG epitaxial process, in particular the influence on the brightness of the is presented. In particular, the doping properties of the poly-SiC source material influence on the brightness of the fluorescent 6H-SiC. In addition we have investigated how the grain orientation...

  5. Creep behavior for advanced polycrystalline SiC fibers

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, G.E.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States); Kohyama, Akira [Kyoto Univ. (Japan)] [and others

    1997-08-01

    A bend stress relaxation (BSR) test is planned to examine irradiation enhanced creep in polycrystalline SiC fibers which are under development for use as fiber reinforcement in SiC/SiC composite. Baseline 1 hr and 100 hr BSR thermal creep {open_quotes}m{close_quotes} curves have been obtained for five selected advanced SiC fiber types and for standard Nicalon CG fiber. The transition temperature, that temperature where the S-shaped m-curve has a value 0.5, is a measure of fiber creep resistance. In order of decreasing thermal creep resistance, with the 100 hr BSR transition temperature given in parenthesis, the fibers ranked: Sylramic (1261{degrees}C), Nicalon S (1256{degrees}C), annealed Hi Nicalon (1215{degrees}C), Hi Nicalon (1078{degrees}C), Nicalon CG (1003{degrees}C) and Tyranno E (932{degrees}C). The thermal creep for Sylramic, Nicalon S, Hi Nicalon and Nicalon CG fibers in a 5000 hr irradiation creep BSR test is projected from the temperature dependence of the m-curves determined during 1 and 100 hr BSR control tests.

  6. Cohort profile: the Social Inequality in Cancer (SIC) cohort study.

    Science.gov (United States)

    Nordahl, Helene; Hvidtfeldt, Ulla Arthur; Diderichsen, Finn; Rod, Naja Hulvej; Osler, Merete; Frederiksen, Birgitte Lidegaard; Prescott, Eva; Tjønneland, Anne; Lange, Theis; Keiding, Niels; Andersen, Per Kragh; Andersen, Ingelise

    2014-12-01

    The Social Inequality in Cancer (SIC) cohort study was established to determine pathways through which socioeconomic position affects morbidity and mortality, in particular common subtypes of cancer. Data from seven well-established cohort studies from Denmark were pooled. Combining these cohorts provided a unique opportunity to generate a large study population with long follow-up and sufficient statistical power to develop and apply new methods for quantification of the two basic mechanisms underlying social inequalities in cancer-mediation and interaction. The SIC cohort included 83 006 participants aged 20-98 years at baseline. A wide range of behavioural and biological risk factors such as smoking, physical inactivity, alcohol intake, hormone replacement therapy, body mass index, blood pressure and serum cholesterol were assessed by self-administered questionnaires, physical examinations and blood samples. All participants were followed up in nationwide demographic and healthcare registries. For those interested in collaboration, further details can be obtained by contacting the Steering Committee at the Department of Public Health, University of Copenhagen, at inan@sund.ku.dk.

  7. A Kochen–Specker inequality from a SIC

    Energy Technology Data Exchange (ETDEWEB)

    Bengtsson, Ingemar [Stockholms Universitet, Fysikum, S-10691 Stockholm (Sweden); Blanchfield, Kate, E-mail: kate@fysik.su.se [Stockholms Universitet, Fysikum, S-10691 Stockholm (Sweden); Cabello, Adán [Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla (Spain); Stockholms Universitet, Fysikum, S-10691 Stockholm (Sweden)

    2012-01-09

    Yu and Oh (eprint) have given a state-independent proof of the Kochen–Specker theorem in three dimensions using only 13 rays. The proof consists of showing that a non-contextual hidden variable theory necessarily leads to an inequality that is violated by quantum mechanics. We give a similar proof making use of 21 rays that constitute a SIC (symmetric informationally-complete positive operator-valued measure) and a complete set of MUB (mutually unbiased bases). A theory-independent inequality is also presented using the same 21 rays, as required for experimental tests of contextuality. -- Highlights: ► We find a state-independent Kochen–Specker inequality in dimension 3 with 21 rays. ► The rays constitute a SIC (9 rays) and a complete set of MUB (12 rays). ► Orthogonalities among the rays produce the Hesse configuration. ► The rays also give a state-independent non-contextual hidden variable inequality. ► We show that both inequalities are violated by quantum mechanics.

  8. Sistem Komunikasi dan Informasi di Indonesia

    Directory of Open Access Journals (Sweden)

    Atie Rachmiatie

    2000-12-01

    Full Text Available Suatu Perubahan dan Tantangan Masa Depan Terdapat perubahan pola komunikasi dan informasi pada masyarakat. terutama perubahan dari segi perangkat keras, perangkat lunak. dan sumber daya manusia, yang berpengaruh terhadap sistem komunikasi dan informasi nasional, baik yang terjadi pada individu maupunpada lembaga/institusi yang berkaitan. Perubahan menyangkut pulapada kondisi organisasi pemerintah yang terkait dengan pengelolaan informasi. yaitu dengan ditata kembalinya sistem administrasi dan manajemen, baik secara intern, maupun ekstern berkaitan dengan organisasi luar. Apresiasi masyarakat terhadap materi informasi. pada kenyataannya. belum tersosialisasikan secara optimal. karena hal ini tergantung pada kebutuhan dan prioritas kebijakan institusi pemerintahan setempat. Dengan demikian. tidak semuajenis isi/materi informasi mendapatkan porsi yang sama dalam pemasyarakatannya.

  9. Microstructure characterization of SiC nanowires as reinforcements in composites

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Ronghua [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yang, Wenshu, E-mail: yws001003@163.com [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wu, Ping [Northwest Institute of Nuclear Technology, Xi' an, 710024 (China); Hussain, Murid [Department of Chemical Engineering, COMSATS Institute of Information Technology, M.A. Jinnah Building, Defence Road, Off Raiwind Road, Lahore 54000 (Pakistan); Xiu, Ziyang; Wu, Gaohui; Wang, Pingping [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-05-15

    SiC nanowires have been rarely investigated or explored along their axial direction by transmission electron microscopy (TEM). Here we report the investigation of the cross-section microstructure of SiC nanowires by embedding them into Al matrix. Morphology of SiC nanowires was cylindrical with smooth surface or bamboo shape. Cubic (3C-SiC) and hexagonal structure (2H-SiC) phases were detected by X-ray diffraction (XRD) analysis. High density stacking faults were observed in both the cylindrical and bamboo shaped nanowires which were perpendicular to their axial direction. Selected area electron diffraction (SAED) patterns of the cylindrical and bamboo shaped SiC nanowires both in the perpendicular and parallel direction to the axial direction were equivalent in the structure. After calculation and remodeling, it has been found that the SAED patterns were composed of two sets of diffraction patterns, corresponding to 2H-SiC and 3C-SiC, respectively. Therefore, it could be concluded that the SiC nanowires are composed of a large number of small fragments that are formed by hybrid 3C-SiC and 2H-SiC structures. - Graphical abstract: Display Omitted - Highlights: • Cross-section microstructure of SiC nanowires was observed in Al composite. • Cylindrical with smooth surface or bamboo shape SiC nanowires were found. • The cylindrical and bamboo shaped SiC nanowires were equivalent in structure. • Structure of SiC nanowires was remodeled. • SiC nanowires are composed of hybrid 3C-SiC and 2H-SiC structures.

  10. KAJIAN BIOAKTIF DAN ZAT GIZI PROPOLIS INDONESIA DAN BRASIL

    Directory of Open Access Journals (Sweden)

    Eliza Halim

    2012-11-01

    Full Text Available ABSTRACTIndonesia has a potency to produce its own propolis, however the propolis market in Indonesia is dominated by imported product, such as from Brazil. Currently, still there is no reasearch which evaluate bioactive compound and nutrient content of Indonesian Propolis (IP compare with Brazilian Propolis (BP. The objectivesof this study were to analyze bioactive compounds and nutrient contents of IP compared to BP. Bioactive compounds and nutrients content were analyzed by gas chromatography–mass spectrophotometry. The resultsshowed both IP and BP contain fenol, α-amyrin, cylolanost, and pyrimidines. Bioactive compounds which specifically found in IP were eudesmane compound, ethyl acridine, lupeol, friedooleanan; while β amyrin and cinnamic acid compound only found in BP. The nutrient contents of IP were higher than BP except for vitamin A. In conclusion, IP might have potential health benefit, similar to BP.Key words: propolis, bioactive, nutrientABSTRAKIndonesia mempunyai potensi untuk menghasilkan propolis tetapi pemasaran propolis di Indonesia didominasi oleh propolis impor seperti propolis yang berasal Brasil. Sampai saat ini belum ada penelitian yang mengungkapkandungan bioaktif dan zat gizi propolis Indonesia (PI dibandingkan dengan propolis Brasil (PB. Oleh karena itu tujuan penelitian ini adalah untuk melakukan kajian kandungan bioaktif dan zat gizi (vitamin dan mineral PI dibandingkan dengan PB. Komponen bioaktif dan kandungn gizi dianalisis dengan metode gas chromatography–mass spectrometry. Hasil analisis menyatakan bahwa baik PI maupun PB mengandung senyawa fenol, α-amyrin, cylolanost, dan pirimidin. Komponen bioaktif unik yang ditemukan di dalam PI adalah senyawaeudesmane, ethyl acridine, lupeol dan friedooleanan; sedangkan β-amyrin dan senyawa asam sinamat hanya ditemukan di dalam PB. Kandungan zat gizi PI lebih tinggi dari PB kecuali kandungan vitamin A. Hal ini menunjukkan bahwa PI kemungkinan mempunyai khasiat untuk

  11. PERBANDINGAN KARAKTERISTIK KIMIA KOPI LUWAK DAN KOPI BIASA DARI JENIS KOPI ARABIKA (Cafeea arabica. L) DAN ROBUSTA (Cafeea canephora. L)

    OpenAIRE

    Israyanti, -

    2012-01-01

    Penelitian ini bertujuan untuk mengetahui perbandingan jumlah kafein, karakteristik proksimat (protein dan lemak) dan rasa dan aroma antara kopi luwak dan kopi biasa dari jenis arabika (Cafeea arabica. L) dan robusta (Cafeea canephora. L). Perlakuan penelitian yakni A1 (luwak robusta), A2 (luwak arabika), B1 (robusta biasa) dan B2 (arabika biasa). Parameter penelitian yaitu pengujian organoleptik pada rasa (metode hedonik) dan aroma (metode ranking), analisa kafein dan uji proksimat berupa ...

  12. PERANAN KOMPETENSI INTI DALAM MERGER DAN AKUISISI

    Directory of Open Access Journals (Sweden)

    Dwi Sulistiani

    2013-11-01

    Full Text Available Dalam era globalisasi dan pedagangan  bebas dewasa ini strategi merger dan akuisisi  merupakan fenomena yang semakin marak dilakukan oleh para pelaku bisnis dan  semakin menarik untuk dicermati bersama. Untuk menjalankan perusahaan para manajemen perusahaan selalu dituntut menjaga pertumbuhan usahanya secara optimal. Penerapan strategi merger dan akuisisi merupakan jalan pintas untuk mewujudkan pertumbuhan usaha tanpa perusahaan perlu memulai dari awal suatu jenis usaha yang baru. Dalam suatu kondisi perusahaan yang kuat cenderung membeli perusahaan lain untuk meningkatkan daya saing dan penghematan biaya. Perusahaan yang terlibat dalam merger dan akuisisi akan dapat diperoleh pangsa pasar yang lebih besar dan efisiensi terhadap biaya. Perusahaan yang merasa tidak dapat bertahan hidup secara individual biasanya merelakan diri untuk menjadi target akuisisi. Merger dan akuisisi merupakan suatu realitas dan tantangan yang harus siap dihadapi oleh para pelaku usaha dalam era perdagangan bebas saat ini. Namun tingkat kesuksesan dalam melakukan kegiatan merger dan akuisisi juga sangat dipengaruhi oleh kondisi internal perusahaan meliputi sumber daya, kapabilitas dan kompetensi inti yang dimiliki oleh perusahaan. Tulisan ini akan mencoba memberikan pemahaman bahwa sumber daya, kapabilitas dan  kompetensi inti merupakan faktor penting dalam melakukan kegiatan penggabungan usaha yang pada akhirnya dapat menentukan tingkat keberhasilan proses merger dan akuisisi yang sedang dijalankan oleh perusahaan

  13. Detection and analysis of particles with failed SiC in AGR-1 fuel compacts

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D., E-mail: hunnjd@ornl.gov [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Baldwin, Charles A.; Gerczak, Tyler J.; Montgomery, Fred C.; Morris, Robert N.; Silva, Chinthaka M. [Oak Ridge National Laboratory (ORNL), P.O. Box 2008, Oak Ridge, TN 37831-6093 (United States); Demkowicz, Paul A.; Harp, Jason M.; Ploger, Scott A. [Idaho National Laboratory (INL), P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States)

    2016-09-15

    Highlights: • Cesium release was used to detect SiC failure in HTGR fuel. • Tristructural-isotropic particles with SiC failure were isolated by gamma screening. • SiC failure was studied by X-ray tomography and SEM. • SiC degradation was observed after irradiation and subsequent safety testing. - Abstract: As the primary barrier to release of radioactive isotopes emitted from the fuel kernel, retention performance of the SiC layer in tristructural isotropic (TRISO) coated particles is critical to the overall safety of reactors that utilize this fuel design. Most isotopes are well-retained by intact SiC coatings, so pathways through this layer due to cracking, structural defects, or chemical attack can significantly contribute to radioisotope release. In the US TRISO fuel development effort, release of {sup 134}Cs and {sup 137}Cs are used to detect SiC failure during fuel compact irradiation and safety testing because the amount of cesium released by a compact containing one particle with failed SiC is typically ten or more times higher than that released by compacts without failed SiC. Compacts with particles that released cesium during irradiation testing or post-irradiation safety testing at 1600–1800 °C were identified, and individual particles with abnormally low cesium retention were sorted out with the Oak Ridge National Laboratory (ORNL) Irradiated Microsphere Gamma Analyzer (IMGA). X-ray tomography was used for three-dimensional imaging of the internal coating structure to locate low-density pathways through the SiC layer and guide subsequent materialography by optical and scanning electron microscopy. All three cesium-releasing particles recovered from as-irradiated compacts showed a region where the inner pyrocarbon (IPyC) had cracked due to radiation-induced dimensional changes in the shrinking buffer and the exposed SiC had experienced concentrated attack by palladium; SiC failures observed in particles subjected to safety testing were

  14. In situ toughened SiC ceramics with Al-B-C additions and oxide-coated SiC platelet/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Cao, J. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

    1996-12-01

    This work aimed at fabrication and characterization of high toughness SiC ceramics through the applications of in situ toughening and SiC platelet reinforcement. The processing-microstructure-property relations of hot pressed SiC with Al, B, and C additions (designated as ABC-SiC) were investigated. Through a liquid phase sintering mechanism, dense SiC was obtained by hot pressing at a temperature as low as 1,700 C with 3 wt% Al, 0.6 wt% B, and 2 wt% C additions. These sintering aids also enhanced the {beta}-to-{alpha} (3C-to-4H) phase transformation, which promoted SiC grains to grow into plate-like shapes. Under optimal processing conditions, the microstructure exhibited high-aspect-ratio plate-shaped grains with a thin (< 1 nm) Al-containing amorphous grain boundary film. The mechanical properties of the toughened SiC and the composites were evaluated in comparison with a commercial Hexoloy SiC under identical test conditions. The C-curve behavior was examined using the strength-indentation load relationship and compared with that directly measured using precracked compact tension specimens. The in situ toughened ABC-SiC exhibited much improved flaw tolerance and a significantly rising R-curve behavior. A steady-state toughness in excess of 9 MPam{sup 1/2} was recorded for the ABC-SiC in comparison to a single valued toughness below 3 MPam{sup 1/2} for the Hexoloy. Toughening in the ABC-SiC was mainly attributed to grain bridging and subsequent pullout of the plate-shaped grains. The high toughness ABC-SiC exhibited a bend strength of 650 MPa with a Weibull modulus of 19; in comparison, the commercial SiC showed a bend strength of 400 MPa with a Weibull modulus of 6. Higher fracture toughness was also achieved by the reinforcement of SiC platelets, encapsulated with alumina, yttria, or silica, in a SiC matrix.

  15. Système d’information comptable et contrôle de gestion dans les entreprises camerounaises

    Directory of Open Access Journals (Sweden)

    Dagobert Ngongang

    2013-12-01

    Full Text Available Cette étude a objet, d’abord, d’identifier quelques spécificités du SIC et des modes de contrôle de gestion, ensuite d’analyser l’impact des facteurs de contingence structurelle sur la pratique de la comptabilité analytique et sur le contrôle de gestion et, enfin, à examiner la relation entre le SIC et le contrôle de gestion.L’analyse des données recueillies par questionnaire administré par entretien direct auprès de 68 entreprises montre que les pratiques comptables sont différenciées, même si on note une prééminence des pratiques de comptabilité générale et de fiscalité. Les TIC sont de plus en plus intégrées dans le SIC et déterminent le rôle du contrôleur de gestion. Deux facteurs de contingence structurelle, la taille et le secteur d’activité, déterminent la pratique de la comptabilité analytique. L’âge de l’entreprise n’explique aucunement le degré d’importance accordé aux outils de contrôle de gestion.

  16. RANCANG BANGUN MODEL KOMPRESI DAN TARIK PERMODELAN SANDBOX DAN MANFAATNYA

    Directory of Open Access Journals (Sweden)

    Fahrudin Fahrudin

    2015-07-01

    Full Text Available Permodelan sandbox dibuat dengan system tektonik konvergen dan divergen dengan menggunakan pergerakan satu sumbu. Permodelan ini bertujuan untuk membuat alat mesin sandbox yang bisa digunakan untuk penelitian dan pengajaran. Mesin berhasil dibuat dan sudah diujicobakan. Ujicoba dengan menggunakan satu lapisan pasir yang diambil dari Formasi Ngrayong. Percobaan selanjutnya dengan beberapa lapisan. Percobaan dilakukan dengan pengamatan yang meliputi pengamatan permukaan dan penampang verikal. Pengamatan yang aspek morfologi, kelurusan struktur, dan perkembangan sesar yang terbentuk. Hasil percobaan menunjukkan bahwa pembentukan morfologi sangat berkaitan dengan pembentukan sesar. Struktur sesar dengan pola forward propagating thrust faults. Sesar tersebut disebabkan imbrikasi. Lipatan yang terbentuk akibat mekanisme propagasi sesar.[Design of Compression and Extensional of the Sandbox Model and Its Benefit] Divergent and convergent tectonic sytem can be studied from the sandbox modelling. This model has a axis of movement. Sandbox models itends to study the progress of structural geology such as fault and fold. We successfully made machine of sandbox. This machine has basal detachment from duraluminum. Material for model is taken by loose sand from Ngrayong Formation. This experiment focused to observation about morphology in surface and thrust or backthrust in subsurface. This experiment has compression system. Result of model was that morphological sequences associated with fault sequences. Fault is formed to have the pattern of forward propagating thrust faults. It’s caused by imbricate thrust system. Folding is formed by the mechanism of fault propagation folding. 

  17. MUWUJUDKAN BUDAYA POLITIK SANTUN, BERSIH DAN BERETIKA DALAM RANGKA MEMPERKOKOH KEHIDUPAN BERBANGSA DAN BERNEGARA

    Directory of Open Access Journals (Sweden)

    Wahyu Widodo

    2014-11-01

    Full Text Available Abstract Makalah ini membahas konsep budaya politik berpusat pada imajinasi (pikiran dan perasaan manusia yang merupakan dasar semua tindakan. Dalam rangka menuju arah pembangunan dan modernisasi suatu masyarakat akan menempuh jalan yang berbeda antara satu masyarakat dengan yang lain, dan itu terjadi karena peranan kebudayaan sebagai salah satu faktor. Budaya politik dapat membentuk aspirasi, harapan, preferensi, dan prioritas tertentu dalam menghadapi tantangan yang ditimbulkan oleh perubahan sosial politik. Pada gilirannya, disimpulkan bahwa peran budaya politik santun, bersih dan beretika dalam rangka memperkokoh kehidupan berbangsa dan bernegara menuju Indonesia baru adalah: pertama, etika politik dan pemerintahan mengandung misi kepada setiap pejabat dan elite politik untuk bersikap jujur, amanah, sportif, siap melayani, berjiwa besar, memiliki keteladanan, rendah hati, dan siap untuk mundur dari jabatan publik apabila terbukti melakukan kesalahan dan secara moral kebijakannya bertentangan dengan hukum dan rasa keadilan masyarakat. Kedua, perlu dilakukan upaya penanaman suatu kesadaran bahwa politik yang hendak kita perjuangkan bukan semata politik kekuasaan, melainkan suatu politik yang mengedepankan panggilan pengabdian demi kesejahteraan masyarakat luas, dialektika antara partai dan politikus serta masyarakat yang kritis. Ketiga, budaya politik santun, bersih dan beretika ini diperlukan karena dapat membuat para elite politik menjauhi sikap dan perbuatan yang dapat merugikan bangsa Indonesia. Akhirnya, disarankan agar dilaksanakan kembali pendidikan budi pekerti yang merupakan pondasi bagi pelaksanaan Civic Education agar tercipta generasi yang tidak hanya mau menjadi politisi, namun paham budaya dan etika politik.   Kata kunci: budaya politik, kehidupan berbangsa dan bernegara, menuju Indonesia baru

  18. Comparing SiC switching power devices: MOSFET, NPN transistor and GTO thyristor

    Science.gov (United States)

    Huang, Alex Q.; Zhang, Bo

    2000-02-01

    This paper for the first time systematically analyzed the operation mechanism of SiC NPN transistors. Theoretical device figure-of-merits for switching power devices based on the conduction loss and switching loss were developed. The on-state loss and the switching loss of 4.5-kV SiC switching power devices (MOSFET, NPN transistor and GTO thyristor) were then compared by using theoretical and numerical calculations. Special emphasis is placed on comparing the total power loss of the devices at a given current density. Theoretical analyses and simulation results show that GTO thyristors have a large switching loss due to the long current tail at turn-off, hence restricting its maximum operation frequency. High voltage SiC MOSFETs have a large on-state power dissipation at high current levels due to the resistive nature of the drift region, restricting their applications at high current densities. SiC NPN transistors have a comparable switching loss as that of SiC MOSFETs, but at the same time, SiC NPN transistors have the lowest on-state loss. This study indicates that SiC NPN transistor is the most attractive switching power device at 4.5 kV.

  19. Application of rapid milling technology for fabrication of SiC nanoparticles.

    Science.gov (United States)

    Kim, Jong-Woong; Shim, Jae-Shik; Kwak, Min-Gi; Hong, Sung-Jei; Cho, Hyun-Min

    2013-09-01

    SiC nanoparticles were successfully fabricated by a high energy ball milling method, so that can be used in the printed electronics to make SiC thin film patterns. Here we utilized the waste of Si sludge for making the SiC nanoparticles. In order to achieve uniform thin film from the nanoparticle ink, fine sized SiC nanoparticles less than 100 nm has to be uniformly dispersed. In this study, we employed the ultra apex milling (UAM) system for particle comminution and dispersion. We investigated the effects of milling parameters, e.g., size of ZrO2 bead and milling time. The size of the SiC particles reached about 103 nm after 4 hours of UAM, when the ZrO2 beads of 50 microm were used. Then SiC ink was formulated with organic solvents and a dispersing agent. A specially designed pattern was printed by an ink-jet printer for evaluating the feasibility of the SiC nanoparticle inks.

  20. Additive Manufacturing of SiC Based Ceramics and Ceramic Matrix Composites

    Science.gov (United States)

    Halbig, Michael Charles; Singh, Mrityunjay

    2015-01-01

    Silicon carbide (SiC) ceramics and SiC fiber reinforcedSiC ceramic matrix composites (SiCSiC CMCs) offer high payoff as replacements for metals in turbine engine applications due to their lighter weight, higher temperature capability, and lower cooling requirements. Additive manufacturing approaches can offer game changing technologies for the quick and low cost fabrication of parts with much greater design freedom and geometric complexity. Four approaches for developing these materials are presented. The first two utilize low cost 3D printers. The first uses pre-ceramic pastes developed as feed materials which are converted to SiC after firing. The second uses wood containing filament to print a carbonaceous preform which is infiltrated with a pre-ceramic polymer and converted to SiC. The other two approaches pursue the AM of CMCs. The first is binder jet SiC powder processing in collaboration with rp+m (Rapid Prototyping+Manufacturing). Processing optimization was pursued through SiC powder blending, infiltration with and without SiC nano powder loading, and integration of nanofibers into the powder bed. The second approach was laminated object manufacturing (LOM) in which fiber prepregs and laminates are cut to shape by a laser and stacked to form the desired part. Scanning electron microscopy was conducted on materials from all approaches with select approaches also characterized with XRD, TGA, and bend testing.

  1. Effect of Ti and Si interlayer materials on the joining of SiC ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang Il; Park, Jung Hwan; Kim, Hyun Gil; Park, Dong Jun; Park, Jeong Yong; Kim, Weon Ju [LWR Fuel Technology Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    SiC-based ceramic composites are currently being considered for use in fuel cladding tubes in light-water reactors. The joining of SiC ceramics in a hermetic seal is required for the development of ceramic-based fuel cladding tubes. In this study, SiC monoliths were diffusion bonded using a Ti foil interlayer and additional Si powder. In the joining process, a very low uniaxial pressure of ∼0.1 MPa was applied, so the process is applicable for joining thin-walled long tubes. The joining strength depended strongly on the type of SiC material. Reaction-bonded SiC (RB-SiC) showed a higher joining strength than sintered SiC because the diffusion reaction of Si was promoted in the former. The joining strength of sintered SiC was increased by the addition of Si at the Ti interlayer to play the role of the free Si in RB-SiC. The maximum joint strength obtained under torsional stress was ∼100 MPa. The joint interface consisted of TiSi{sub 2}, Ti{sub 3}SiC{sub 2}, and SiC phases formed by a diffusion reaction of Ti and Si.

  2. Tribological Behavior ofTi3SiC2-based Material

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The wear and friction properties of Ti3SiC2-based materials were studied using the pin-on-disc method. The friction coefficient of Ti3SiC2-based material was not very sensitive to normal load, the steady state value, μ, increased from 0.4 to 0.5 when the normal load increased from 7.7 N to 14.7 N. The wear volume for Ti3SiC2 disc increased with increasing normal load or sliding distance in the tests. The average wear rate of Ti3SiC2-based material was 9.9×10-5 mm3/Nm. The debris on the Ti3SiC2 disc was essentially made up of Ti3SiC2 and steel pin materials,while the debris on the steel sliders was generally pi.n material. The wear mechanism was concluded as the fracture and delamination of Ti3SiC2-based materials followed by adhesive wear of steel sliders.

  3. Preparation and Microstructure of Cu/Ti3SiC2 Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li; SHENG Wen-bin; CHEN Zong-min

    2006-01-01

    Mixed micron-sized Cu/Ti3SiC2 (vol5%) powder was mechanically milled using agate balls and zirconia balls separately. Then followed an examination of it with the FEI-SEM. The experimental results show that, distributed homogenously in Cu matrix, the Ti3SiC2 particles have a size of about 30-50 nm after milled with agate balls for 8 h, while it remains approximately unchanged after milled with zirconia balls. The microstructure of the mixture at different ball-milling stages was also studied. Bulks of Cu/Ti3SiC2 nano-composite were fabricated by hot pressing nano-sized Cu/Ti3SiC2 powder at the temperature of 1 073 K under 100 MPa. Then came an investigation of the effects of the particle size and agglomerate state of Ti3SiC2 as well as the microstructure of Cu/Ti3SiC2 nano-composite. It was found that the nano-sized Ti3SiC2 particles distribute evenly in copper.

  4. Electronic properties of MoS{sub 2} on monolayer, bilayer and bulk SiC: A density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Zan, Wenyan; Geng, Wei [State Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Liu, Huanxiang [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Yao, Xiaojun, E-mail: xjyao@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

    2016-05-05

    The structure and electronic properties of MoS{sub 2} and SiC (single-layer SiC, double layer SiC, C-terminated SiC and Si-terminated SiC) composites were investigated by using density functional theory calculations. The calculation results show that the electronic properties of MoS{sub 2} are modified at different levels by combining with different thickness of SiC. The heterostructures (MoS{sub 2}/C-terminated SiC and MoS{sub 2}/Si-terminated SiC) possess larger binding energies than MoS{sub 2}/single-layer SiC and MoS{sub 2}/bilayer SiC, suggesting the higher stability for MoS{sub 2}/C-terminated SiC and MoS{sub 2}/Si-terminated SiC composites. It is found that charge transfer is from SiC to MoS{sub 2} in these heterostructures. MoS{sub 2}/single-layer SiC, MoS{sub 2}/double-layer SiC and MoS{sub 2}/C-terminated SiC are semiconductors, whereas MoS{sub 2}/Si-terminated SiC has no gap. - Highlights: • The structure and electronic properties of MoS{sub 2}/SiC composites were investigated. • The electronic property of MoS{sub 2} can be modulated by SiC with different thickness. • The MoS{sub 2}/Si-terminated SiC has higher stability than MoS{sub 2}/C-terminated SiC.

  5. KORELASI ANTARA ISLAM DAN EKONOMI

    Directory of Open Access Journals (Sweden)

    Akmal Zainal Abidin

    2015-03-01

    Full Text Available CORELATION BETWEEN ISLAM AND ECONOMY. This paper aims to identifies about the correlation between economic and Islam. Islam is the perfect religion that governs all things in life, including the economy. This is evident with the concept of  well-being which is described in the al-Quran and Sunnah. Basically the goal of every human life is to prosper, although humans make sense of  well- being with a different perspective. Most understand economics assume that welfare is the welfare of  earthly material. But to make sense of well-being with the term al-Falah, is meaning holistic wellbeing and balance between material and spiritual dimensions. al-Quran and Sunnah have taught that the human being will be achieved if  living in balance between material and spiritual. This is because human life does not just stop in the life of this world, but there is still a second life that will be faced by humanity in the hereafter, and well-being will be achieved with the truth is that people can balance the needs of the world and the hereafter, and that is what is taught in Islamic economics. Keywords: Islam, Economy, Prosperity. Tulisan ini bertujuan untuk menjelasakn tentang korelasi antara ekonomi  dan  Islam.  Islam  adalah  agama  yang  sempurna  yang mengatur segala hal dalam kehidupan ini, termasuk juga ekonomi. Hal ini terbukti dengan konsep kesejahteraan yang dipaparkan dalam al-Quran dan Sunnah. Pada dasarnya tujuan hidup setiap manusia adalah untuk mencapai kesejahteraan, meskipun manusia memaknai kesejahteraan dengan perspektif  yang berbeda-beda. Sebagian besar paham ekonomi menganggap bahwa kesejahteraan adalah kesejahteraan material duniawi. Namun Islam memaknai kesejahteraan dengan istilah  Falah  yang  berarti  kesejahteraan  holistik  dan  seimbang antara dimensi material dan spiritual. Al-Quran dan Sunnah telah mengajarkan bahwa kesejahteraan akan tercapai jika manusia menjalani hidup secara seimbang antara material dan

  6. Détermination de la polarisation des gluons dans le nucléon par la production de hadrons à grande impulsion transverse à COMPASS

    CERN Document Server

    Procureur, Sébastien

    L\\'objectif principal de l\\'expérience COMPASS au CERN est la détermination de la polarisation des gluons dans le nucléon, $\\\\frac{\\\\Delta G}{G}$. On mesure pour cela l\\'asymétrie d\\'hélicité du processus de fusion photon gluon, dans la diffusion de muons polarisés sur une cible de deutérons polarisés. Ce processus peut être sélectionné par la production de hadrons à grande impulsion transverse ($p_T$), ce qui permet de disposer d\\'une grande statistique. En contrepartie, la présence d\\'un bruit de fond physique complique l\\'extraction de $\\\\frac{\\\\Delta G}{G}$. Ce mémoire de thèse présente différentes études menées afin d\\'optimiser la détermination de $\\\\frac{\\\\Delta G}{G}$ dans ce canal. Une étude sur l\\'alignement des quelques 200 plans de détection est notamment présentée, améliorant ainsi la résolution du spectromètre. Les performances des 12 détecteurs de type Micromegas ont également été déterminées au cours de la prise de données 2004. Puis, les asymétries obtenues...

  7. KINERJA KEPALA SEKOLAH DALAM KEGIATAN BIMBINGAN DAN KONSELING

    Directory of Open Access Journals (Sweden)

    Abu Bakar M.Luddin

    2014-06-01

    Abstrak: Kinerja Kepala Sekolah dalam Kegiatan Bimbingan dan Konseling. Penelitian ini bertujuan mendeskripsikan kinerja kepala sekolah dalam pelaksanaan kegiatan bimbingan dan konseling. Penelitian dilaksanakan di SMU Negeri 2 Kota Binjai, dengan memergunakan rancangan deskriptif kualitatif. Subjek penelitian adalah kepala sekolah, koordinator bimbingan dan konseling, dan guru pembimbing. Data di­kumpulkan dengan observasi, wawancara mendalam, dan kajian dokumen, dan selanjutnya dianalisis sete­lah melalui proses triangulasi antarsubjek dan informasi. Temuan penelitian menunjukkan bahwa kinerja kepala sekolah terkait dengan pelaksanaan kegiatan bimbingan dan konseling masih belum sepenuhnya sebagaimana yang diharapkan. Kepala sekolah perlu meningkatkan kinerjanya dalam menjalankan fungsi koordinasi dan kepengawasan untuk mencapai kegiatan bimbingan dan konseling yang efektif.

  8. IKLIM SEKOLAH DAN EFIKASI KENDIRI DALAM KALANGAN GURU BIMBINGAN DAN KAUNSELING SEKOLAH MENENGAH DI KELANTAN

    OpenAIRE

    Ibrahim, Hasliza; Ismail, Siti Noor; Kassim, Mohamad Adnan Mohamad; Mohamad, Suhaila

    2017-01-01

    Artikel ini bertujuan untuk mengenal pasti hubungan antara iklim sekolah dan efikasi kendiri guru bimbingan dan kaunseling di negeri Kelantan.  Responden kajian adalah terdiri daripada 181 orang guru bimbingan dan kaunseling Sekolah Menengah di negeri Kelantan.  Kajian rintis dijalankan ke atas 30 orang guru bimbingan dan kaunseling di daerah Tanah Merah.  Secara spesifiknya, kaedah kuantitatif digunakan untuk tujuan pengumpulan data.  Maklum balas melalui soal selidik telah diperolehi dan se...

  9. SiC multi-layer protective coating on carbon obtained by thermionic vacuum arc method

    Science.gov (United States)

    Ciupina, V.; Lungu, C. P.; Vladoiu, R.; Epure, T.-D.; Prodan, G.; Roşca, C.; Porosnicu, C.; Jepu, I.; Belc, M.; Prodan, M.; Stanescu, I. M.; Stefanov, C.; Contulov, M.; Mandes, A.; Dinca, V.; Vasile, E.; Zarovschi, V.; Nicolescu, V.

    2013-09-01

    SiC single-layer or multi-layer on C used to improve the oxidation resistance and tribological properties of C have been obtained by Thermionic Vacuum Arc (TVA) method. The 200nm thickness carbon thin films was deposed on glass or Si substrate and then 100÷500 nm thickness SiC successively layers on carbon thin film was deposed. The microstructure and mechanical characteristics of as-prepared SiC coating were investigated by Transmission Electron Microscopy (TEM, STEM), Energy Dispersive X-Ray Spectroscopy (EDS), Electron Scattering Chemical Analysis (ESCA) and tribological techniques. Samples containing SiC single-layer or multi-layer coating on carbon were investigated up to 1000°C. The results of thermal treatments reveals the increase of oxidation resistance with increase of the number of SiC layers. The mechanism of oxidation protection is based on the reaction between SiC and elemental oxygen resulting SiO2 and CO. The tribological behavior of SiC coatings was evaluated with a tribometer with ball-on-disk configuration from CSM device with 6mm diameter sapphire ball, sliding speed in dry conditions being 0.2m/s, with normal contact loads of 0.5N, 1N, 1.5N and 2N, under unlubricated conditions. The friction coefficient on SiC was compared with the friction coefficient on uncoated carbon layer. Electrical surface resistance of SiC coating on carbon at different temperatures was measured comparing the potential drop on the sample with the potential drop on a series standard resistance in constant mode.

  10. Graphene nanoribbons anchored to SiC substrates

    Science.gov (United States)

    Le, Nam B.; Woods, Lilia M.

    2016-09-01

    Graphene nanoribbons are quasi-one-dimensional planar graphene allotropes with diverse properties dependent on their width and types of edges. Graphene nanoribbons anchored to substrates is a hybrid system, which offers novel opportunities for property modifications as well as experimental control. Here we present electronic structure calculations of zigzag graphene nanoribbons chemically attached via the edges to the Si or C terminated surfaces of a SiC substrate. The results show that the edge characteristics are rather robust and the properties are essentially determined by the individual nanoribbon. While the localized spin polarization of the graphene nanoribbon edge atoms is not significantly affected by the substrate, secondary energy gaps in the highest conduction and lowest valence region may emerge in the anchored structures. The van der Waals interaction together with the electrostatic interactions due to the polarity of the surface bonds are found to be important for the structure parameters and energy stability.

  11. Demonstration of SiC Pressure Sensors at 750 C

    Science.gov (United States)

    Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender

    2014-01-01

    We report the first demonstration of MEMS-based 4H-SiC piezoresistive pressure sensors tested at 750 C and in the process confirmed the existence of strain sensitivity recovery with increasing temperature above 400 C, eventually achieving near or up to 100% of the room temperature values at 750 C. This strain sensitivity recovery phenomenon in 4H-SiC is uncharacteristic of the well-known monotonic decrease in strain sensitivity with increasing temperature in silicon piezoresistors. For the three sensors tested, the room temperature full-scale output (FSO) at 200 psig ranged between 29 and 36 mV. Although the FSO at 400 C dropped by about 60%, full recovery was achieved at 750 C. This result will allow the operation of SiC pressure sensors at higher temperatures, thereby permitting deeper insertion into the engine combustion chamber to improve the accurate quantification of combustor dynamics.

  12. Relativistic energies for the SiC radical

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Chun-Sheng [Southwest Petroleum University, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu (China); Shui, Zheng-Wei [Southwest Petroleum University, School of Vocational and Technical Education, Nanchong (China)

    2015-11-15

    The analytical solutions of the Dirac equation with the modified Rosen-Morse potential energy model have been explored. Under the condition of the spin symmetry, we present the bound state energy equation. In the nonrelativistic limit, the relativistic energy equation becomes the nonrelativistic energy form deduced within the framework of the Schroedinger equation. We find that the relativistic effect of the relative motion of the ions leads to a little decrease in the vibrational energies when the vector potential is equal to the scalar potential for the electronic ground state of the SiC radical, while to an increase in those if the vector potential is greater than the scalar potential. (orig.)

  13. Kandidiasis di Mulut akibat Khemoterapi dan Penatalaksanaannya

    OpenAIRE

    2016-01-01

    Latar belakang: kandidiasis (kandidosis) adalah infeksi jamur yang disebabkan oleh spesies Candida biasanya Candida albicans. Faktor predisposisi yang memicu kandidiasis adalah terganggunya ekologi mulut karena antara lain pemakaian antibiotika, kortikosteroid, penyakit kronis dan keganasan, beberapa gangguan darah; terapi radiasi di leher dan kepala; khemoterapi; leukimia, obat sitotoksik, juga kebersihan mulut yang buruk. Tujuan: melaporkan kasus kandidiasis di mulut karena khemoterapi dan ...

  14. PEMBELAJARAN SENI TARI: AKTIF, INOVATIF DAN KREATIF

    OpenAIRE

    Gandes Nurseto

    2015-01-01

    Pendidikan seni tari perlu diberikan pada Sekolah Dasar karena keunikan, kebermaknaan terletak pada pemberian pengalaman estetik dalam bentuk berapresiasi dan menggunakan model pembelajaran yang PAIKEM Pembelajaran, Aktif, Inovatif, Kreatif, Efektif dan Menyenagkan dalam proses pembelajaran didalam kelas dari Standar Kompetensi dan Komptensi Dasar mengapresiasi karya seni tari tunggal nusantara yang bertujuan untuk mengenalkan karya seni tari daerah lain. Masalah dalam penelitian ini bagaiman...

  15. Incorporation of oxygen in SiC implanted with hydrogen

    Science.gov (United States)

    Barcz, A.; Jakieła, R.; Kozubal, M.; Dyczewski, J.; Celler, G. K.

    2015-12-01

    Oxygen accumulation at buried implantation-damage layers was studied after post-implantation annealing of hydrogen- or deuterium-implanted 4H-SiC. In this study H+ or 2H+ implantation was carried out at energies E, from 200 keV to 1 MeV, to fluences D, ranging from 2 × 1016/cm2 to 1 × 1017/cm2. For comparison, the implantation was also done into float-zone (FZ) and Czochralski (CZ) silicon wafers. Post-implantation annealing at temperatures from 400 °C to 1150 °C was performed either in pure argon or in a water vapor. Characterization methods included SIMS, RBS and TEM. At sufficiently high doses, hydrogen implantation into semiconductors leads to the irreversible formation of a planar zone of microcavities, bubbles and other extended defects located at the maximum of deposited energy. This kind of highly perturbed layer, containing large amounts of agglomerated hydrogen is known to efficiently getter a number of impurities. Oxygen was detected in both CZ and FZ silicon subjected to Smart-Cut™ processing. We have identified, by SIMS profiling, a considerable oxygen peak situated at the interface between the SiC substrate and a layer implanted with 1 × 1017 H ions/cm2 and heated to 1150 °C in either H2O vapor or in a nominally pure Ar. In view of a lack of convincing evidence that a hexagonal SiC might contain substantial amounts of oxygen, the objective of the present study was to identify the source and possible transport mechanism of oxygen species to the cavity band. Through the analysis of several implants annealed at various conditions, we conclude that, besides diffusion from the bulk or from surface oxides, an alternative path for oxygen agglomeration is migration of gaseous O2 or H2O from the edge of the sample through the porous layer.

  16. High temperature flow behaviour of SiC reinforced lithium aluminosilicate composites

    Indian Academy of Sciences (India)

    Santanu Das; V S R Murthy; G S Murty

    2001-04-01

    The compressive flow behaviour of lithium aluminosilicate (LAS) glass, with and without SiC particulate reinforcements, was studied. The LAS glass crystallized to spodumene during high-temperature testing. The flow behaviour of LAS glass changed from Newtonian to non-Newtonian due to the presence of crystalline phase. Further, with the addition of 40 vol.% SiC additions, the strain rate sensitivity of flow stress decreased. While the activation energy for flow in LAS was 300 kJ/mole, it increased to 995 kJ/mole with the addition of 40 vol.% SiC reinforcements.

  17. Effects of SiC and MgO on aluminabased ceramic foams filters

    Directory of Open Access Journals (Sweden)

    CAO Da-li

    2007-11-01

    Full Text Available Alumina-based foam ceramic filters were fabricated by using alumina, SiC, magnesia powder as major materials. It has been found that this ceramic filter has a uniform macrostructure for filtering molten metals. The influences of SiC and magnesia content, the sintering temperatures on ceramic properties were discussed. Aluminabased foam ceramic filters containing 2.2 mass% magnesia and 7.6 mass% SiC has a compressive strength of 1.36 MPa and a thermal shock resistance of 5 times. Its main phases after 1 hour sintering at 1 500 consist of alumina, silicon carbide, spinel and mullite.

  18. Electrical Impact of SiC Structural Crystal Defects on High Electric Field Devices (Invited)

    Science.gov (United States)

    Neudeck, Philip G.

    1999-01-01

    As illustrated by the invited paper at this conference and other works, SiC wafers and epilayers contain a variety of crystallographic imperfections, including micropipes, closed-core screw dislocations, grain boundaries, basal plane dislocations, heteropolytypic inclusions, and surfaces that are often damaged and contain atomically rough features like step bunching and growth pits or hillocks. Present understanding of the operational impact of various crystal imperfections on SiC electrical devices is reviewed, with an emphasis placed on high-field SiC power devices and circuits.

  19. High Speed Lapping of SiC Ceramic Material with Solid (Fixed) Abrasives

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YANG Xin-hong; SHANG Chun-min; HU Xiao-yong; HU Zhong-hui

    2005-01-01

    An experimental investigation is carried out to machine SiC ceramic material through the method of high speed plane lapping with solid(fixed) abrasives after the critical condition of brittle-ductile transition is theoretically analyzed. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasives for brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic in the ductile mode using W3.5 grit and a high efficiency, low cost and smooth surface with a surface roughness of Ra 2.4nm can be achieved.

  20. Exposure of epitaxial graphene on SiC(0001) to atomic hydrogen.

    Science.gov (United States)

    Guisinger, Nathan P; Rutter, Gregory M; Crain, Jason N; First, Phillip N; Stroscio, Joseph A

    2009-04-01

    Graphene films on SiC exhibit coherent transport properties that suggest the potential for novel carbon-based nanoelectronics applications. Recent studies suggest that the role of the interface between single layer graphene and silicon-terminated SiC can strongly influence the electronic properties of the graphene overlayer. In this study, we have exposed the graphitized SiC to atomic hydrogen in an effort to passivate dangling bonds at the interface, while investigating the results utilizing room temperature scanning tunneling microscopy.

  1. A route to strong p-doping of epitaxial graphene on SiC

    KAUST Repository

    Cheng, Yingchun

    2010-11-09

    The effects of Au intercalation on the electronic properties of epitaxialgraphenegrown on SiC{0001} substrates are studied using first principles calculations. A graphenemonolayer on SiC{0001} restores the shape of the pristine graphene dispersion, where doping levels between strongly n-doped and weakly p-doped can be achieved by altering the Au coverage. We predict that Au intercalation between the two C layers of bilayer graphenegrown on SiC{0001} makes it possible to achieve a strongly p-doped graphene state, where the p-doping level can be controlled by means of the Au coverage.

  2. The intensive terahertz electroluminescence induced by Bloch oscillations in SiC natural superlattices.

    Science.gov (United States)

    Sankin, Vladimir; Andrianov, Alexandr; Petrov, Alexey; Zakhar'in, Alexey; Lepneva, Ala; Shkrebiy, Pavel

    2012-10-09

    : We report on efficient terahertz (THz) emission from high-electric-field-biased SiC structures with a natural superlattice at liquid helium temperatures. The emission spectrum demonstrates a single line, the maximum of which shifts linearly with increases in bias field. We attribute this emission to steady-state Bloch oscillations of electrons in the SiC natural superlattice. The properties of the THz emission agree fairly with the parameters of the Bloch oscillator regime, which have been proven by high-field electron transport studies of SiC structures with natural superlattices.

  3. Kronig-Penney-like description for band gap variation in SiC polytypes

    Science.gov (United States)

    Backes, W. H.; de Nooij, F. C.; Bobbert, P. A.; van Haeringen, W.

    1996-02-01

    A one-dimensional Kronig-Penney-like model for envelope wave functions is presented to explain the band gap variation of SiC polytypes. In this model the envelope functions obey discontinuous boundary conditions. The electronic band gaps of cubic and several hexagonal and rhombohedral SiC polytypes are calculated. The polytypic superlattices are assumed to be stackings of differently sized and orientated cubic SiC segments. The empirical Choyke-Hamilton-Patrick relation is understood and deviating trends for small hexagonalities and rhombohedral modifications are predicted.

  4. Thermoelastic stresses in SiC single crystals grown by the physical vapor transport method

    Institute of Scientific and Technical Information of China (English)

    Zibing Zhang; Jing Lu; Qisheng Chen; V.Prasad

    2006-01-01

    A finite element-based thermoelastic anisotropic stress model for hexagonal silicon carbide polytype is developed for the calculation of thermal stresses in SiC crystals grown by the physical vapor transport method.The composite structure of the growing SiC crystal and graphite lid is considered in the model.The thermal expansion match between the crucible lid and SiC crystal is studied for the first time.The influence of thermal stress on the dislocation density and crystal quality iS discussed.

  5. Effect of SiC particle size on the microstructure and properties of cold-sprayed Al/SiCp composite coating

    Science.gov (United States)

    Yu, Min; Hua, Junwei

    2017-07-01

    The Al5056/SiC composite coatings were prepared by cold spraying. Experimental results show that the SiC content in the composite coating deposited with the SiC powder having an average size of 67 μm (Al5056/SiC-67) is similar to that deposited with the SiC powder having an average size of 27 μm (Al5056/SiC-27). The microhardness and cohesion strength of Al5056/SiC-67 coating are higher than those of the Al5056/SiC-27 coating. In addition, the Al5056/SiC-67 coating having a superior wear resistance because of the coarse SiC powder with a superior kinetic energy contributes to the deformation resistance of the matrix Al5056 particles.

  6. D-region ion-neutral coupled chemistry (Sodankylä Ion Chemistry, SIC) within the Whole Atmosphere Community Climate Model (WACCM 4) - WACCM-SIC and WACCM-rSIC

    Science.gov (United States)

    Kovács, Tamás; Plane, John M. C.; Feng, Wuhu; Nagy, Tibor; Chipperfield, Martyn P.; Verronen, Pekka T.; Andersson, Monika E.; Newnham, David A.; Clilverd, Mark A.; Marsh, Daniel R.

    2016-09-01

    This study presents a new ion-neutral chemical model coupled into the Whole Atmosphere Community Climate Model (WACCM). The ionospheric D-region (altitudes ˜ 50-90 km) chemistry is based on the Sodankylä Ion Chemistry (SIC) model, a one-dimensional model containing 307 ion-neutral and ion recombination, 16 photodissociation and 7 photoionization reactions of neutral species, positive and negative ions, and electrons. The SIC mechanism was reduced using the simulation error minimization connectivity method (SEM-CM) to produce a reaction scheme of 181 ion-molecule reactions of 181 ion-molecule reactions of 27 positive and 18 negative ions. This scheme describes the concentration profiles at altitudes between 20 km and 120 km of a set of major neutral species (HNO3, O3, H2O2, NO, NO2, HO2, OH, N2O5) and ions (O2+, O4+, NO+, NO+(H2O), O2+(H2O), H+(H2O), H+(H2O)2, H+(H2O)3, H+(H2O)4, O3-, NO2-, O-, O2, OH-, O2-(H2O), O2-(H2O)2, O4-, CO3-, CO3-(H2O), CO4-, HCO3-, NO2-, NO3-, NO3-(H2O), NO3-(H2O)2, NO3-(HNO3), NO3-(HNO3)2, Cl-, ClO-), which agree with the full SIC mechanism within a 5 % tolerance. Four 3-D model simulations were then performed, using the impact of the January 2005 solar proton event (SPE) on D-region HOx and NOx chemistry as a test case of four different model versions: the standard WACCM (no negative ions and a very limited set of positive ions); WACCM-SIC (standard WACCM with the full SIC chemistry of positive and negative ions); WACCM-D (standard WACCM with a heuristic reduction of the SIC chemistry, recently used to examine HNO3 formation following an SPE); and WACCM-rSIC (standard WACCM with a reduction of SIC chemistry using the SEM-CM method). The standard WACCM misses the HNO3 enhancement during the SPE, while the full and reduced model versions predict significant NOx, HOx and HNO3 enhancements in the mesosphere during solar proton events. The SEM-CM reduction also identifies the important ion-molecule reactions that affect the partitioning of

  7. Experimental determination of grain density function of AZ91/SiC composite with different mass fractions of SiC and undercoolings using heterogeneous nucleation model

    Directory of Open Access Journals (Sweden)

    J. Lelito

    2011-02-01

    Full Text Available The grain density, Nv, in the solid state after solidification of AZ91/SiC composite is a function of maximum undercooling, ΔT, of a liquid alloy. This type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the alloy. The aim of this paper was selection of parameters for the model describing the relationship between the grain density of primary phase and undercooling. This model in connection with model of crystallisation, which is based on chemical elements diffusion and grain interface kinetics, can be used to predict casting quality and its microstructure. Nucleation models have parameters, which exact values are usually not known and sometimes even their physical meaning is under discussion. Those parameters can be obtained after mathematical analysis of the experimental data. The composites with 0, 1, 2, 3 and 4wt.% of SiC particles were prepared. The AZ91 alloy was a matrix of the composite reinforcement SiC particles. This composite was cast to prepare four different thickness plates.They were taken from the region near to the thermocouple, to analyze the undercooling for different composites and thickness plates and its influence on the grain size. The microstructure and thermal analysis gave set of values that connect mass fraction of SiC particles, and undercooling with grain size. These values were used to approximate nucleation model adjustment parameters. Obtained model can be very useful in modelling composites microstructure.

  8. Mechanical Spectroscopy of MgB2 Containing Sic / Spektroskopia Mechaniczna MgB2 Zawierającego Sic

    Directory of Open Access Journals (Sweden)

    Silva M.R.

    2015-12-01

    Full Text Available The compound magnesium diboride (MgB2 has been well-known since the 1950s; however, its superconducting properties were unknown. Intrinsic characteristics of MgB2 make this material a promising candidate for technological applications, although the low value of the irreversibility field and the decrease in critical current density with the increase in the magnetic field considerably reduce its utility. The present work aimed to study the effect of carbon-based doping on anelastic properties of MgB2 as measured by mechanical spectroscopy. The samples were prepared by using the powder-intube method. The samples were made with 5, 7.5, and 10 wt.% of silicon carbide (SiC. The results reveal complex mechanical loss spectra caused by the interaction between point defects and surface defects in the crystalline lattice of MgB2.

  9. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    Science.gov (United States)

    Bendaoud, Adlane Larbi

    . Dans la partie theorique, un modele traitant les aspects thermique, hydrodynamique et massique a ete elabore. Sur la base de ce modele a ete ecrit un programme informatique en langage FORTRAN 6.6. Il est base sur la discretisation du serpentin en volumes de controle, est entierement automatise et peut traiter des echangeurs de chaleur avec des circuits de refrigerant complexes pouvant avoir des entrees et sorties multiples ainsi que des bifurcations. La presence simultanee des trois phases thermodynamiques du refrigerant (liquide sous refroidi, fluide sature, vapeur surchauffee) dans le serpentin est aussi prise en charge. Le modele a ete valide pour un fonctionnement avec et sans formation de givre en utilisant des donnees experimentales disponibles dans la litterature et celles obtenues sur le banc d'essai de CanmetENERGIE. Celui-ci a ete mis a jour pour les besoins de la presente recherche et pour cela, un systeme de surchauffe et d'injection de la vapeur d'eau dans une enceinte a tres basse temperature a ete dimensionne, fabrique et installe. Un dispositif de visualisation de la formation de givre, ainsi qu'un equipement de mesure de la temperature, de la pression et de l'humidite relative de l'air ont aussi ete ajoutes. Une fois le modele valide, des simulations numeriques sur le serpentin avec et sans formation de givre ont ete effectuees. Un premier cas de base a servi comme reference pour d'autres cas pour lesquels une etude parametrique sur la geometrie et le fonctionnement a ete menee. Il a ete montre par rapport au cas de base que : 1. la diminution de la densite des ailettes sur des rangees specifiques du serpentin donne une surface minimale (Amin) plus grande, retardant ainsi l'obstruction totale du serpentin par le givre et permet donc un temps de fonctionnement plus grand et une frequence de degivrage plus faible. 2. une bonne configuration de circuit de refrigerant augmente le temps de fonctionnement du serpentin de 200 % et delivre une puissance

  10. Pengaturan dan Pengawasan pada Bank Syariah

    Directory of Open Access Journals (Sweden)

    Ali Syukron

    2012-06-01

    Full Text Available Peran bank dalam melaksanakan tugas dan fungsinya perlu diatur secara baik dan benar. Hal ini bertujuan untuk menjaga kepercayaan nasabah terhadap aktivitas perbankan. Salah satu peraturan yang perlu dibuat untuk mengatur perbankan adalah peraturan mengenai permodalan bank yang berfungsi sebagai penyangga terhadap kemungkinan terjadinya kerugian. Tulisan ini merupakan studi pustaka dimana penulis mengelaborasi bagaimana pengaturan dan pengawasan pada bank syariah yang ada di berbagai negera. Dalam tulisan ini, penulis mengambil sampel negara Malaysia,  Pakistan, Kuwait, dan Inggris. Alasan memilih keempat negara tersebut karena Malaysia dan Kuwait memiliki kemiripan dengan Indonesia yang mengadopsi dual banking system.

  11. Fabrication of mullite-bonded porous SiC ceramics from multilayer-coated SiC particles through sol-gel and in-situ polymerization techniques

    Science.gov (United States)

    Ebrahimpour, Omid

    In this work, mullite-bonded porous silicon carbide (SiC) ceramics were prepared via a reaction bonding technique with the assistance of a sol-gel technique or in-situ polymerization as well as a combination of these techniques. In a typical procedure, SiC particles were first coated by alumina using calcined powder and alumina sol via a sol-gel technique followed by drying and passing through a screen. Subsequently, they were coated with the desired amount of polyethylene via an in-situ polymerization technique in a slurry phase reactor using a Ziegler-Natta catalyst. Afterward, the coated powders were dried again and passed through a screen before being pressed into a rectangular mold to make a green body. During the heating process, the polyethylene was burnt out to form pores at a temperature of about 500°C. Increasing the temperature above 800°C led to the partial oxidation of SiC particles to silica. At higher temperatures (above 1400°C) derived silica reacted with alumina to form mullite, which bonds SiC particles together. The porous SiC specimens were characterized with various techniques. The first part of the project was devoted to investigating the oxidation of SiC particles using a Thermogravimetric analysis (TGA) apparatus. The effects of particle size (micro and nano) and oxidation temperature (910°C--1010°C) as well as the initial mass of SiC particles in TGA on the oxidation behaviour of SiC powders were evaluated. To illustrate the oxidation rate of SiC in the packed bed state, a new kinetic model, which takes into account all of the diffusion steps (bulk, inter and intra particle diffusion) and surface oxidation rate, was proposed. Furthermore, the oxidation of SiC particles was analyzed by the X-ray Diffraction (XRD) technique. The effect of different alumina sources (calcined Al2O 3, alumina sol or a combination of the two) on the mechanical, physical, and crystalline structure of mullite-bonded porous SiC ceramics was studied in the

  12. ANALISIS PEMBELAJARAN HUMANIS DAN KONSTRUKTIVISKARAKTER, DAN KEMAMPUAN LITERASI MATEMATIKA

    Directory of Open Access Journals (Sweden)

    Muhammad Jazimul Ni’am

    2014-02-01

    Full Text Available AbstrakTujuan penelitian ini adalah untuk mengetahui pencapaian indikator teori humanismedankonstruktivismedalamperencanaan, bahanajar,danprosespembelajaranmateritrigonometri. Selainitu, ingindiketahui kemampuanliterasi matematikadankarakteryangmunculsebagaihasilbelajar.Penelitianinimerupakanpenelitiankualitatif.Instrumen yang disusun dan dikembangkan terdiri dari instrumen penila-ian perangkat pembelajaran,instrumen penilaian proses pembelajaran, tes kemampuanliterasimatematika,daninstrumenpenilaiankarakter.Validitasinstrumenpenelitianditentukanberdasarkan validasitimahli dan hasil tes uji cobadi lapangan.Teknikpengumpulandata yaitudenganmetode tes,observasi,wawancara,dan angket.Analisisdatadilakukan sebelum,selama, dan setelah penelitianberupaanalisisdiskriptif kualitatif.Keabsahan data hasil penelitian diuji menggunakan metode trianggulasidata. PenilaianterhadapRPP dan proses pembelajaranberada pada levelyangrendah, penilaian bahan ajar tergolong sedang jika dilihat daritiga aspek yaitupembelajaranhumanis,konstruktivis,dankemampuanliterasimatematika.Pencapaiankemampuan literasi matematikamasihdalam levelmenerjemahkanmasalahkontekstualkemodelmatematika dan belummampumencapai tahap menerapkandanmenafsirkan.Ketujuhkarakteryangdiamati belumsepenuhnyaterlihat. Karakteryangterlihat selamapembelajaran adalah jujur,toleransi,tanggungjawab,rasaingintahu, dan percayadiri.AbstractThe purpose of  this study was to determine the achievement indicators humanism andconstructivism theory in planning, teaching materials, and learning materials in matter trigonometry.In addition, it will be analyzedthe mathematical literacyskills andcharacterthatappearsas a resultof learning. This research is qualitative. The instrument was conceived anddeveloped is instrument to assess of  learning tools such as lesson plans and teaching materials, learning assessment, tests of  mathematical literacy skills, and instrument of  character. Validi-ty instruments of

  13. STRUKTUR DAN PRODUKSI LEBAH Trigona spp. PADA SARANG BERBENTUK TABUNG DAN BOLA

    Directory of Open Access Journals (Sweden)

    Putu Ade Hinduari Putra

    2015-12-01

    Full Text Available Lebah tanpa sengat (Trigona spp. dapat menghasilkan madu yang bermanfaat bagi kesehatan. Penelitian bertujuan untuk mengetahui : (1 morfologi Trigona spp., (2 struktur internal sarang Trigona spp. pada sarang berbentuk tabung dan bola, (3 volume sarang serta perkiraan produksi madu, beebread dan selanakan Trigona spp. pada sarang berbentuk tabung dan bola. Penelitian dilaksanakan pada bulan November 2014. Sampel yang digunakan adalah koloni dan sarang Trigona spp. berbentuk tabung dan bola yang diambil di Desa Padang Tunggal,Kecamatan Selat, Kabupaten Karangasem, Bali. Hasil penelitian menunjukan bahwa nama spesies dari sampel koloni Trigona spp. pada sarang berbentuk tabung dan bola adalah Trigona laeviceps. Struktur internal sarang Trigona spp. pada sarang berbentuk tabung dan bola mempunyai pola susunan yaitu pot madu, pot beebread dan pot sel anakan. Volume sarang besar memberikan perkiraan total jumlah produksi madu, beebread dan selanakan lebih banyak dibandingkan volume sarang kecil.

  14. PERAN KEPALA SEKOLAH DAN PUSTAKAWAN DALAM PEMBERDAYAAN PERPUSTAKAAN SD MUHAMMADIYAH SAPEN DAN SD NEGERI GIWANGAN

    Directory of Open Access Journals (Sweden)

    Widya Setyaningrum Bagyoastuti

    2016-04-01

    Full Text Available Penelitian ini bertujuan untuk mendeskripsikan: (1 peran kepala sekolah dalam memberdayakan perpustakaan sekolah dasar, dan (2 peran pustakawan dalam memberdayakan perpustakaan sekolah dasar. Pendekatan kualitatif digunakan dalam penelitian ini dengan menjadikan perpustakaan SD Muhammadiyah Sapen dan SD Negeri Giwangan sebagai subjek penelitian. Data penelitian dikumpulkan melalui teknik observasi, wawancara, dan dokumentasi kemudian dianalisis dengan mengacu pada model interaktif menurut Miles dan Huberman. Hasil penelitian menunjukkan bahwa pemberdayaan perpustakaan sekolah dasar dimulai manakala terdapat dukungan kepala sekolah dan hadirnya pustakawan penuh waktu yang profesional. Kepala sekolah berperan sebagai (1 manajer sekolah, (2 pemimpin instruksional, dan (3 agen perubahan. Pustakawan berperan sebagai (1 manajer perpustakaan, (2 ahli informasi dan penggiat literasi informasi, (3 pelaku instruksional, dan (4 kolaborator. Pemberdayaan perpustakaan dapat dilakukan dengan (1 meningkatkan partisipasi warga sekolah dalam pengembangan koleksi pustaka, (2 meningkatkan kolaborasi antara pustakawan dengan guru dalam pembelajaran, dan (3 pengembangan literasi informasi yang terintegrasi ke dalam pembelajaran.

  15. ETIKA BISNIS AL-GHAZALI DAN ADAM SMITH DALAM PERSPEKTIF ILMU BISNIS DAN EKONOMI

    Directory of Open Access Journals (Sweden)

    AM. M. Hafidz MS.

    2013-05-01

    Full Text Available Penelitian ini adalah untuk mengeksplorasi: (1 pembangunan etika bisnis yang telah dirumuskan oleh al-Ghazali dan Adam Smith, (2 persamaan dan perbedaan antara dua etika bisnis pria, dan (3 relevansi bisnis mereka etika bisnis modern dunia dan ekonomi. Bisnis etika dibangun oleh al-Ghazali dan Smith di dataran praksis tidak jauh berbeda. Etika bisnis konstruksi dibangun oleh al-Ghazali didasarkan pada prinsip-prinsip seperti orientasi itikad baik tentang dunia dan akhirat, kejujuran, kepentingan pribadi dan social keseimbangan, dan perilaku / perbuatan yang tepat. Di sisi lain, etika bisnis konstruksi dibangun oleh Smith, berdasarkan keadilan, altruisme, keadilan dan liberal (kebebasan ekonomi. Baik etika bisnis yang diperkenalkan oleh kedua sangat relevan untuk menjadi digunakan sebagai bahan pokok acuan dalam etika bisnis modern.

  16. PENGARUH PEMBERIAN HIJAUAN DAN KONSENTRAT MENGANDUNG UREA-KAPUR DAN UBI KAYU TERHADAP PENAMPILAN KAMBING PE

    Directory of Open Access Journals (Sweden)

    I G. Mahardika

    2015-06-01

    Full Text Available Penelitian telah dilakukan untuk mengetahui pengaruh pemberian hijauan dan konsentrat yang mengandung urea-kapur dan ubi kayu terhadap produktivitas kambing. Penelitian menggunakan Rancangan Acak Lengkap dengan 4 perlakuan dan 4 ulangan. Ke empat perlakuan yang dicobakan adalah Perlakuan A: ransum dengan 75% konsentrat (mengandung 4% urea, 2% kapur dan 50% ubikayu dan 25% hijauan (40% gamal dan 60% rumput raja, perlakuan B: rasnsum yang terdiri 60% konsentrat 40% hijauan, perlakuan C: ransum dengan 45% konsentrat dan 55% hijauan dan perlakuan D: ransum dengan 30% konsentrat dan 70% hijauan. Hasil penelitian mendapatkan bahwa produktivitas kambing yang mendapat ransum dengan level konsentrat 45% sampai 75% tidak berbeda sedangkan yang mendapat ransum dengan level konsentrat 30% lebih rendah. Ransum yang memebrikan nilai ekonomi tertinggi adalah ransum yang mengandung konsentrat antara 45% sampai 60%.

  17. IDENTIFIKASI DAN TEKNIK PENGENDALIAN HAMA DAN PENYAKIT BENIH PULAI (Alstonia scholaris

    Directory of Open Access Journals (Sweden)

    Evayusvita Rustam

    2016-09-01

    Full Text Available Tujuan dari penelitian ini adalah mengidentifikasi dan mengendalikan hama dan penyakit benih pulai yang terbawa dari lapangan. Identifikasi cendawan dilakukan dengan menginkubasi benih selama 7 hari, sedangkan untuk pengendalian terhadap hama dan penyakit benih diberi insektisida nabati dan kimia. Dari hasil identifikasi jenis cendawan pada benih pulai yaitu Aspergillus sp, Curvularia sp., Fusarium sp., Penicillium sp. dan Rhizopus sp. Persentase infeksi cendawan tertinggi pada benih pulai asal Nagrak (Aspergillus sp. sebesar 92%, Curvularia sp. 29% dan Fusarium sp. 21%, sedangkan persentase infeksi cendawan terendah pada benih pulai asal Jambi (Aspergillus sp. 2% dan Fusarium sp. 1%. Perlakuan terbaik yang dapat mengendalikan hama pada benih pulai adalah perlakuan yang diberi ekstrak daun suren dalam wadah plastik tertutup dan disimpan di ruang suhu kamar 270C selama 2 bulan. Pengendalian penyakit, terbaik pada benih adalah memberi bubuk kunyit ke dalam wadah plastik tertutup dan disimpan di lemari es 160C. Perlakuan tersebut menghasilkan daya kecambah masing-masing 70%.

  18. Méthode sous-optimale de commande des transistors Grand Gap dans un convertisseur DC/DC réversible isolé

    OpenAIRE

    Cougo, Bernardo; Schneider, Henri

    2014-01-01

    National audience; De nombreux travaux cherchent à améliorer les performances des convertisseurs d'énergie électrique embarqués à bord des futurs avions. Les transistors à base de carbure de silicium (SiC) et nitrure de gallium (GaN), qui peuvent commuter plus rapidement que leurs homologues à base de silicium, offrent, dans ce cadre, des perspectives intéressantes. Cet article présente l'étude d'un convertisseur DC/DC Bidirectionnel Isolé (appelé Dual Active Bridge, DAB) qui fera l'interface...

  19. Sistem Informasi Penjualan dan Pemesanan Layanan Berbasis Web dan SMS Gateway di Petshop "PetZone"

    Directory of Open Access Journals (Sweden)

    Siska Fadhilah Wati

    2013-09-01

    Full Text Available Dewasa ini teknologi informasi sangat membantu dalam dunia bisnis. Kemudahan yang ditawarkan akan menjaring lebih banyak konsumen. Namun, perusahan tingkat menengah seperti PetZone saat ini masih jarang yang menawarkan kemudahan berbelanja atau pemesanan layanan secara online. Oleh karena itu diperlukan sebuah sistem berbasis web di perusahaan PetZone yang dapat memudahkan pemilik dan karyawan dalam apenjualan, pelayanan, dan pemasaran, serta memudahkan pelanggan dalam jual-beli barang dan jasa. Atas dasar masalah tersebut dibangun Sistem Informasi Penjualan dan Pemesanan Layanan Berbasis Web dan SMS Gateway untuk menunjang proses bisnis yang ada. Sistem informasi dibangun menggunakan bahasa pemrograman PHP framework Codeigniter, javascript untuk tampilan yang dinamis, dan database MySQL. Proses pembuatan dan pengembangan Sistem Informasi Penjualan ini menggunakan metode air terjun. Metode air terjun meliputi kebutuhan pengguna, analisis, rancangan, implementasi dan pengujian. Pemodelan Sistem Informasi yang dibangun menggunakan metode berorientasi objek UML (Unified Modeling Language yang terdiri dari Use case  diagram, Class diagram dan Sequence diagram. Hasil pengujian Sistem Informasi Penjualan dan Pemesanan Layanan Berbasis Web dan SMS Gateway menunjukkan bahwa semua fitur yang terdapat baik dalam sistem informasi maupun SMS gateway dapat bekerja dengan baikdengan ratusan sample data, dan server SMS gateway dapat memproses lebih dari satu SMS secara bersamaan. Dalam perkembangan ke depannya nanti, Sistem Informasi Penjualan dan Pemesanan Layanan Berbasis Web dan SMS Gateway masih dapat dikembangkan lagi dengan menambah fitur-fitur pada SMS gateway sehingga lebih memudahkan konsumen.

  20. Switching Investigations on a SiC MOSFET in a TO-247 Package

    DEFF Research Database (Denmark)

    Anthon, Alexander; Hernandez Botella, Juan Carlos; Zhang, Zhe

    2014-01-01

    This paper deals with the switching behavior of a SiC MOSFET in a TO-247 package. Based on simulations, critical parasitic inductances in the circuit layout are analyzed and their effect on the switching losses highlighted. Especially the common source inductance, a critical parameter in a TO-247...... package, has a major influence on the switching energy. Crucial design guidelines for an improved double pulse test circuit are introduced which are used for practical investigations on the switching behavior. Switching energies of a SiC MOSFET in a TO-247 package is measured depending on varying gate...... resistance and loop inductances. With total switching energy of 340.24 μJ, the SiC MOSFET has more than six times lower switching losses than a regular Si IGBT. Implementing the SiC switches in a 3 kW T-Type inverter topology, efficiency improvements of 0.8 % are achieved and maximum efficiency of 97...

  1. Selective Growth of Graphene by Pulsed Laser Annealing Ion Implanted SiC

    Science.gov (United States)

    Berke, Kara; Wang, Xiaotie; Rudawski, Nick; Venkatachalam, Dinesh; Fridmann, Joel; Gila, Brent; Ren, Fan; Elliman, Rob; Hebard, Arthur; Appleton, Bill

    2014-03-01

    We report a method for site-selective graphene growth on SiC for direct nano-scale patterning of graphene. Crystalline SiC was implanted with Si and C ions to amorphize the sample surface, then subjected to pulsed laser annealing (PLA); graphene growth occurred only where ions were implanted. PLA parameters including the fluence, number of pulses, and annealing environment were investigated to optimize the growth process. Our previous work involving Au, Cu, and Ge implants in SiC suggested that both the implanted species and surface amorphization affect graphene growth. In this work, we show that surface amorphization alone, without the presence of foreign ionic species, can be used with PLA to create site-selective graphene growth on SiC. Samples were characterized using Raman spectroscopy and cross-sectional transmission electron microscopy. also affiliated with Raith USA, Incorporated.

  2. Numerical design of SiC bulk crystal growth for electronic applications

    Science.gov (United States)

    Wejrzanowski, T.; Grybczuk, M.; Tymicki, E.; Kurzydlowski, K. J.

    2014-10-01

    Presented study concerns numerical simulation of Physical Vapor Transport (PVT) growth of bulk Silicon Carbide (SiC) crystals. Silicon Carbide is a wide band gap semiconductor, with numerous applications due to its unique properties. Wider application of SiC is limited by high price and insufficient quality of the product. Those problems can be overcame by optimizing SiC production methods. Experimental optimization of SiC production is expensive because it is time consuming and requires large amounts of energy. Numerical modeling allows to learn more about conditions inside the reactor and helps to optimize the process at much lower cost. In this study several simulations of processes with different reactor geometries were presented along with discussion of reactor geometry influence on obtained monocrystal shape and size.

  3. Fabrication of SiC nanowire thin-film transistors using dielectrophoresis

    Institute of Scientific and Technical Information of China (English)

    Dai Zhenqing; Zhang Liying; Chen Changxin; Qian Bingjian; Xu Dong; Chen Haiyan; Wei Liangming; Zhang Yafei

    2012-01-01

    The selection of solvents for SiC nanowires (NWs) in a dielectrophoretic process is discussed theoretically and experimentally.From the viewpoints of dielectrophoresis force and torque,volatility,as well as toxicity,isopropanol (IPA) is considered as a proper candidate.By using the dielectrophoretic process,SiC NWs are aligned and NW thin films are prepared.The densities of the aligned SiC NWs are 2 μm-1,4 μm-1,6 μm-1,which corresponds to SiC NW concentrations of 0.1 μg/μL,0.3μg/μL and 0.5 μg/μL,respectively.Thin-film transistors are fabricated based on the aligned SiC NWs of 6 μm-1.The mobility of a typical device is estimated to be 13.4 cm2/(V.s).

  4. SUPERPOLISHED SI COATED SIC OPTICS FOR RAPID MANUFACTURE OF LARGE APERTURE UV AND EUV TELESCOPES Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSG/Tinsley proposes an innovative optical manufacturing process that will allow the advancement of state-of-the-art Silicon Carbide (SiC) mirrors for large aperture...

  5. Ultra-Lightweight, High Efficiency Silicon-Carbide (SIC) Based Power Electronic Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business of Innovation Research Phase I proposal seeks to investigate and prove the feasibility of developing highly efficient, ultra-lightweight SiC...

  6. Large area SiC coating technology of RBSC for semiconductor processing component

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Yeon; Kim, Weon Ju

    2001-06-01

    As the semiconductor process is developed for the larger area wafer and the larger-scale integration, the processing fixtures are required to have excellent mechanical and high temperature properties. This highlights the importance of silicon carbide-based materials as a substitute for quartz-based susceptors. In this study, SiC coating technology on reaction sintered (RS) SiC with thickness variation of +/- 10% within a diameter of 8 inch by low pressure chemical vapor deposition has been developed for making a plate type SiC fixture such as heater, baffle, etc., with a diameter of 12 inch. Additionally, a state of art on fabrication technology and products of the current commercial SiC fixtures has been described.

  7. Carbon Nanotube (CNT) and Carbon Fiber Reinforced SiC Optical Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — M Cubed has developed and patented technology to make carbon fiber reinforced SiC composites and components. In addition, the feasibility of doubling the toughness...

  8. Synthesis and characteristics of SiC whiskers with "rosary bead" morphology

    Institute of Scientific and Technical Information of China (English)

    Xian Jia; Xiaomei Ling

    2004-01-01

    SiC whiskers with ″rosary bead″ morphology were synthesized using suitable silicon source and carbon source through solid reaction at the temperature above 1537 K. The diameter and length of the SiC whiskers were about 0.1-1.0 μm and 20-100 μm,respectively. The largest diameter of their enlarged ends of the whiskers was about 0.2-1.0 μm, and it gradually and smoothly decreased to the size of the plain part of the whiskers. The results of X-ray diffraction analysis show that the crystalline structure of the obtained SiC whiskers is β-SiC. It is considered that the SiC whiskers grow via a vapor-solid mechanism.

  9. Visible Blind SiC Array with Low Noise Readout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To date, we have (i) designed and fabricated both common cathode and common anode SiC detector arrays; (ii) designed and fabricated the detector packaging (FPA), and...

  10. Optical properties in 1D photonic crystal structure using Si/C60 multilayers

    Institute of Scientific and Technical Information of China (English)

    Chen Jing; Tang Jiyu; Han Peide; Chen Junfang

    2009-01-01

    The feasibility of using Si/C60 mulfilayer films as one-dimensional(1D)photonie band gap crystals was investigated by theoretical calculations using a transfer matrix method(TMM).The response has been studied both within and out of the periodic plane of Si/C60 multilayers.It is found that Si/C60 multilayer films show incomplete photonic band gap(PBG)behavior in the visible frequency range.The fabricated Si/C60 multilayers with two pairs of 70 am C60 and 30 nm Si layers exhibit a PBG at central wavelength of about 600 nm.and the highest reflectivity call reach 99%.As a consequence,this photonic crystal may be important for fabricating a photonic crystal with an incomplete band gap in the visible frequency range.

  11. Identification of -SiC surrounded by relatable surrounding diamond medium using weak Raman surface phonons

    Indian Academy of Sciences (India)

    Mohan Kumar Kuntumalla; Harish Ojha; Vadali Venkata Satya Siva Srikanth

    2013-11-01

    It is difficult to detect -SiC using micro-Raman scattering, if it is surrounded by carbon medium. Here, -SiC is identified in the presence of a relatable surrounding diamond medium using subtle, but discernible Raman surface phonons. In this study, diamond/-SiC nanocomposite thin film system is considered in which nanosized -SiC crystallites are surrounded by a relatable nanodiamond medium that leads to the appearance of a weak Raman surface phonon band at about 855 cm-1. Change in the nature of the surrounding material structure and its volume content when relatable, will affect the resultant Raman response of -SiC phase as seen in the present case of diamond/-SiC nanocomposite thin films.

  12. Decentralized Nonlinear Controller Based SiC Parallel DC-DC Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is aimed at demonstrating the feasibility of a Decentralized Control based SiC Parallel DC-DC Converter Unit (DDCU) with targeted application for...

  13. Breakthrough in Power Electronics from SiC: May 25, 2004 - May 31, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Marckx, D. A.

    2006-03-01

    This report explores the premise that silicon carbide (SiC) devices would reduce substantially the cost of energy of large wind turbines that need power electronics for variable speed generation systems.

  14. Hybrid surface structures for efficiency enhancement of fluorescent SiC for white LED application

    DEFF Research Database (Denmark)

    Ou, Yiyu; Xiong, Meng; Lu, Weifang

    Hybrid structures contain structures in both micro- and nano-meter scale have been fabricated on fluorescent SiC by applying a fast fabrication method. Luminescence efficiency of f-SiC was enhanced significantly compared with normal nanostructures....

  15. Toxicity assessment of SiC nanofibers and nanorods against bacteria.

    Science.gov (United States)

    Szala, Mateusz; Borkowski, Andrzej

    2014-02-01

    In the present study, evidence of the antibacterial effects of silicon carbide (SiC) nanofibers (NFSiC) and nanorods (NRSiC) obtained by combustion synthesis has been presented. It has been shown that the examined bacteria, Pseudomonas putida, could bind to the surface of the investigated SiC nanostructures. The results of respiration measurements, dehydrogenase activity measurements, and evaluation of viable bacteria after incubation with NFSiC and NRSiC demonstrated that the nanostructures of SiC affect the growth and activity of the bacteria examined. The direct count of bacteria stained with propidium iodide after incubation with SiC nanostructures revealed that the loss of cell membrane integrity could be one of the main effects leading to the death of the bacteria.

  16. Silicon Carbide (SiC) Power Processing Unit (PPU) for Hall Effect Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR project, APEI, Inc. is proposing to develop a high efficiency, rad-hard 3.8 kW silicon carbide (SiC) Power Processing Unit (PPU) for Hall Effect...

  17. Ultra-Lightweight, High Efficiency Silicon-Carbide (SIC) Based Power Electronic Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Phase I of this project, APEI, Inc. proved the feasibility of creating ultra-lightweight power converters (utilizing now emerging silicon carbide [SiC] power...

  18. Synthesis of One-Dimensional SiC Nanostructures from a Glassy Buckypaper

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Mengning; Star, Alexander

    2013-02-21

    A simple and scalable synthetic strategy was developed for the fabrication of one-dimensional SiC nanostructures - nanorods and nanowires. Thin sheets of single-walled carbon nanotubes (SWNTs) were prepared by vacuum filtration and were washed repeatedly with sodium silicate (Na₂SiO₃) solution. The resulting “glassy buckypaper” was heated at 1300 - 1500 °C under Ar/H₂ to allow a solid state reaction between C and Si precursors to form a variety of SiC nanostructures. The morphology and crystal structures of SiC nanorods and nanowires were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive xray spectroscopy (EDX), electron diffraction (ED) and x-ray diffraction (XRD) techniques. Furthermore, electrical conductance measurements were performed on SiC nanorods, demonstrating their potential applications in high-temperature sensors and control systems.

  19. Current Status in Layered Ternary Carbide Ti3SiC2, a Review

    Institute of Scientific and Technical Information of China (English)

    H.B.Zhang; Y.W.Bao; Y.C.Zhou

    2009-01-01

    This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Followings are the synthetic strategies that have been exploited to achieve, and the formation mechanism of Ti3SiC2. Then we devote much attentions to the mechanical properties and oxidation/hot corrosion behaviors of Ti3SiC2 as well as some advances achieved recently. At the end of this paper, we elaborate on some new discoveries in the Ti3SiC2 system, and also give a brief discussion focused on the "microstructure -property" relationship.

  20. Study of indentation induced cracks in MoSi2-reaction bonded SiC ceramics

    Indian Academy of Sciences (India)

    O P Chakrabarti; P K Das; S Mondal

    2001-04-01

    MoSi2–RBSC composite samples were prepared by infiltration of Si–2 at.% Mo melt into a preform of commercial SiC and petroleum coke powder. The infiltrated sample had a density > 92% of the theoretical density (TD) and microstructurally contained SiC, MoSi2, residual Si and unreacted C. The material was tested for indentation fracture toughness at room temperature with a Vicker’s indenter and KIC was found to be 4.42 MPa√m which is around 39% higher than the conventional RBSC material. Enhancement in indentation fracture toughness is explained in terms of bowing of propagating cracks through MoSi2/SiC interface which is under high thermal stress arising from the thermal expansion mismatch between MoSi2 and SiC.

  1. Analysis on partial thermal resistances of packaged SiC schottky barrier diodes at elevated temperatures

    Science.gov (United States)

    Kim, Taehwa; Funaki, Tsuyoshi

    2016-04-01

    This paper investigates the temperature dependence of partial thermal resistances of a packaged SiC schottky barrier diode (SBD) for high temperature applications. Transient thermal resistances of the packaged SiC SBD were measured and characterized in temperature range from 27 to 275 °C. The partial thermal resistances were extracted and analyzed using the cumulative and differential thermal structure functions. The extracted partial thermal resistances were compared to the results from the finite difference thermal model, and both results were in good agreement. The temperature dependence of the partial thermal resistance of the SiC device and the Si3N4 substrate contributes to the overall thermal characteristics variation of the packaged SiC SBD.

  2. Light and heavy element isotopic compositions of mainstream SiC grains.

    Energy Technology Data Exchange (ETDEWEB)

    Amari, S.; Clayton, R. N.; Davis, A. M.; Lewis, R. S.; Pellin, M. J.

    1999-02-03

    Although a variety of types of pre-solar SiC grains have been classified by their C, N, and Si isotopic composition, the majority of such grains are so-called mainstream grains and are believed to have come from asymptotic giant branch stars [1]. We have previously reported the Mo isotopic compositions of presolar SiC grains whose C, N, and Si isotopic compositions were not known [2]. Since most presolar SiC grains fall in the mainstream group, we assumed that these grains were mainstream. The excellent match of the Mo isotopic data with expectations for nucleosynthesis in AGB stars was consistent with this identification. In order to better understand the distribution of isotopic compositions in presolar grains, we have begun to measure heavy element isotopic compositions of presolar SiC grains of known C, N and Si isotopic composition.

  3. Research Progress on Preparation for Biomass-based SiC Ceramic

    Directory of Open Access Journals (Sweden)

    CUI He-shuai

    2017-08-01

    Full Text Available Silicon carbide (SiC ceramics prepared by the conventional process has excellent properties and wide application prospects, but the increased cost of high-temperature preparation process restricts its further development. In contrast, the abundant porous structure of biomass makes itself to be ideal replacement of SiC ceramic prepared at low temperature. This paper reviewed the structure characteristics, preparation methods, pyrolysis mechanism and influence parameters of biomass-based SiC ceramic, and eventually explored the current problems and development trends of the pretreatment of carbon source and silicon source, the pyrolysis process and the application research on the preparation for biomass-based SiC ceramic.

  4. Light extraction efficiency enhancement for fluorescent SiC based white light-emitting diodes

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini

    fluorescent Boron-Nitrogen co-doped 6H SiC is optimized in terms of source material, growth condition, dopant concentration, and carrier lifetime by using photoluminescence, pump-probe spectroscopy etc. The internal quantum efficiency is measured and the methods to increase the efficiency have been explored......Fluorescent SiC based white light-emitting diodes(LEDs) light source, as an innovative energy-efficient light source, would even have longer lifetime, better light quality and eliminated blue-tone effect, compared to the current phosphor based white LED light source. In this paper, the yellow....... At a device level, the focus is on improving the light extraction efficiency due to the rather high refractive index of SiC by nanostructuring the surface of SiC. Both periodic nanostructures made by e-beam lithography and nanosphere lithography and random nanostructures made by self-assembled Au nanosphere...

  5. FABRICATION AND MATERIAL ISSUES FOR THE APPLICATION OF SiC COMPOSITES TO LWR FUEL CLADDING

    Directory of Open Access Journals (Sweden)

    WEON-JU KIM

    2013-08-01

    Full Text Available The fabrication methods and requirements of the fiber, interphase, and matrix of nuclear grade SiCf/SiC composites are briefly reviewed. A CVI-processed SiCf/SiC composite with a PyC or (PyC-SiCn interphase utilizing Hi-Nicalon Type S or Tyranno SA3 fiber is currently the best combination in terms of the irradiation performance. We also describe important material issues for the application of SiC composites to LWR fuel cladding. The kinetics of the SiC corrosion under LWR conditions needs to be clarified to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In addition, the development of end-plug joining technology and fission products retention capability of the ceramic composite tube would be key challenges for the successful application of SiC composite cladding.

  6. PERANCANGAN DAN PENGEMBANGAN PROTOTYPE SISTEM PARKIR

    Directory of Open Access Journals (Sweden)

    Indah Ayu Septriyaningrum

    2016-10-01

    Abstrak  Sistem parkir manual pada pelayanan parkir mall memerlukan pengelolaan dan pengembangan sistem yang lebih rumit dan jauh dari kata efisien. Informasi yang didapatkan pengelola parkir terkait kondisi parkir di lapangan setiap harinya masih kurang. Tujuan dari penelitian ini adalah merancang dan mengembangkan prototype sistem parkir. Metode pengembangan dan perancangan sistem pada penelitian ini adalah metode Waterfall. Hasil yang didapatkan adalah sistem ini dapat mendeteksi keberadaan mobil pada slot parkir yang tersedia dengan bantuan Intel Galileo Board Gen 2 sebagai kontroler, sensor LDR (Light Dependent Resistor dan sensor ultrasonik (PING sebagai alat bantu pendeteksi keberadaan mobil. Sistem dapat menampilkan aktifitas parkir pada aplikasi web seperti kondisi lahan parkir kosong, lahan terisi, waktu masuk, waktu keluar, lama parkir dan kapasitas parkir yang tersedia serta grafik pemakaian lahan parkir. Dapat disimpulkan bahwa perancangan dan pengembangan sistem berhasil diimplementasikan. Kata Kunci : Sistem parkir, waterfall, Intel Galileo Board Gen 2,sensor LDR (Light Dependent Resistor, sensor ultrasonik

  7. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Lamichhane, Ranjan [APEI, Inc.; Shepherd, Paul [APEI, Inc.; Glover, Michael [APEI, Inc.

    2014-01-01

    This paper presents a high-temperature capable intelligent power module that contains SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter (Fig. 1) to determine the performance of the module in a system level application. The converter was operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The peak efficiency was found to be 97.5% at 2.9 kW.

  8. Conversion of wood flour/SiO2/phenolic composite to porous SiC ceramic containing SiC whiskers

    Directory of Open Access Journals (Sweden)

    Li Zhong

    2013-01-01

    Full Text Available A novel wood flour/SiO2/phenolic composite was chosen to be converted into porous SiC ceramic containing SiC whiskers via carbothermal reduction. At 1550°C the composite is converted into porous SiC ceramic with pore diameters of 10~40μm, and consisting of β-SiC located at the position of former wood cell walls. β-SiC wire-like whiskers of less than 50 nm in diameter and several tens to over 100 μm in length form within the pores. The surface of the resulting ceramic is coated with β-SiC necklace-like whiskers with diameters of 1~2μm.

  9. KUALITAS PRODUK DAN KUALITAS LAYANAN TERHADAP KEPUASAN DAN LOYALITAS NASABAH

    Directory of Open Access Journals (Sweden)

    Kharisma Nawang Sigit

    2017-05-01

    Full Text Available This study described the effect of product quality and service quality on sustomer satisfaction and loyalty. The population in this study was the customers of Kredit Usaha Rakyat at BRI Warungasem. The sampling method used in this research was purposive sampling. The samples in this study were 100 customers in People’s Business Credit (Kredit Usaha Rakyat BRI Batang Branch Unit Warungasem who had already taken at least two time KUR credits. The instrument of answers measurement used was a Likert scale 1-7 alternative answers. Testing instrument used was validity and reliability, and testing the model used was the coefficient of determination and F test (goodness of fit. Testing the hypothesis in this study used t test. Variables used in the study were product quality, service quality, customer satisfaction and loyalty.The results showed that there was the effect on the product quality and customer satisfaction. Service quality affected the customer satisfaction. Product quality affect the customer loyalty. The quality of service had an effect on customer loyalty. Customer satisfaction had an effect on customer loyalty. Penelitian ini menjelaskan pengaruh kualitas produk dan kualitas layanan terhadap kepuasan nasabah dan loyalitas. Populasi pada penelitian ini adalah nasabah Kredit Usaha Rakyat BRI Unit Warungasem. Metode pengambilan sampel yang digunakan dalam penelitian ini adalah purposive sampling. Sampel dalam penelitian ini adalah 100 nasabah Kredit Usaha Rakyat di BRI Cabang Batang Unit Warungasem yang sudah mengambil minimal dua kali kredit KUR.Pengukuran jawaban instrumen menggunakan skala likert 1-7alternatif jawaban. Pengujian instrumen menggunakan validitas dan reliabilitas, pengujian model menggunakan koefisien determinasi, dan uji F (goodness of fit. Pengujian hipotesis dalam penelitian ini menggunakan uji t. Variabel yang digunakan dalam penelitian yaitu Kualitas Produk, kualitas layanan, kepuasan dan loyalitas nasabah. Hasil

  10. GRIYA DAN OMAH Penelusuran Makna dan Signifikasi di Arsitektur Jawa

    Directory of Open Access Journals (Sweden)

    Josef Prijotomo

    1999-01-01

    Full Text Available Terms and names in architecture may sometimes be powerful in exploring history of ideas. Philology and hermeneutics are discipline of knowledge that utilize this notion in a very throgh and critical way. Inspired by those discipline of knowledge, this musing on `Griya' and `Omah' tries to demonstrate that their meaning is not `house' as many still understand them. Rather, both terms understood by the Jawanese as `any building' constructed. Critical assessment upon old documents named `Kawruh Griya' not only supportive for this understanding among the Javanese, but also provide us with a hint on one of ideals of `what a home is' among the Jawanese. The Javanese once had a notion that to dwell in a house is like sheltering under a shady tree. Since `griya' and `omah' may open our musing up to regions and cultures outside Jawa, this paper will limit its musing within the Jawanese. Abstract in Bahasa Indonesia : Kata, sebutan dan istilah yang digunakan dalam arsitektur terkadang memiliki kemampuan untuk membantu dan menjadi bahan kajian sejarah bagi dunia arsitektur. Kajian filologi dan hermeneutika dengan baik telah memanfaatkan kemampuan tersebut. Tanpa harus memaksakan diri untuk mengikuti dengan ketat bidang pengetahuan tersebut, penelusuran atas arti `griya' dan `omah' ini mencoba untuk mengungkap sebagian kecil dari sejarah arsitektur Jawa. Melalui interpretasi-menerangkan (Poespoprodjo 1987: 194-195 atas arti kedua kata tersebut di dalam berbagai naskah Kawruh Griya, keduanya samasekali tidak memiliki arti: `rumah'. Dengan penelusuran ini ditemukan pula petunjuk yang mengarah pada salah satu gagasan orang Jawa tentang rumah yakni `bagaikan berteduh di bawah pohon'. Meskipun kedua kata tersebut dapat membawa penelusuran ini ke wilayah di luar arsitektur dan masyarakat Jawa, harus diakui bahwa penelusuran ini masih dibatasi pada telusuran internal bahasa Jawa, yakni hanya mengkaji kedua kata tersebut di dalam perjalanan kebahasaan bahasa Jawa

  11. Investigation on the Short Circuit Safe Operation Area of SiC MOSFET Power Modules

    DEFF Research Database (Denmark)

    Reigosa, Paula Diaz; Luo, Haoze; Iannuzzo, Francesco

    2016-01-01

    This paper gives a better insight of the short circuit capability of state-of-the-art SiC MOSFET power modules rated at 1.2 kV by highlighting the physical limits under different operating conditions. Two different failure mechanisms have been identified, both reducing the short-circuit capability......) of the studied SiC MOSFET power modules is formulated based on the two proposed criteria....

  12. drs (Distantly Related sic) Gene Polymorphisms among emm12-Type Streptococcus pyogenes Isolates

    OpenAIRE

    Brandt, Claudia M.; Haase, Gerhard; Spellerberg, Barbara; Holland, Regina; Lütticken, Rudolf

    2003-01-01

    Twenty-eight emm12-type Streptococcus pyogenes isolates from patients with invasive and noninvasive infections or from asymptomatic carriers were genetically typed. Sequencing of drs (distantly related sic [streptococcal inhibitor of complement]) genes identified two novel alleles and revealed a polymorphism for drs similar to that of sic. No association was observed between the five different drs alleles and the five restriction patterns of the vir regulon for the isolates studied. These dat...

  13. Passivation of surface-nanostructured f-SiC and porous SiC

    DEFF Research Database (Denmark)

    Ou, Haiyan; Lu, Weifang; Ou, Yiyu

    The further enhancement of photoluminescence from nanostructured fluorescent silicon carbide (f-SiC) and porous SiC by using atomic layer deposited (ALD) Al2O3 is studied in this paper.......The further enhancement of photoluminescence from nanostructured fluorescent silicon carbide (f-SiC) and porous SiC by using atomic layer deposited (ALD) Al2O3 is studied in this paper....

  14. Powder metallurgical processing of a SiC particle reinforced Al-6wt.%Fe alloy

    OpenAIRE

    Staniek, G.; Lehnert, F.; Peters, M; Bunk, W.; Kaysser, W.

    1993-01-01

    Discontinuously reinforced aluminum alloys for elevated temperatures with a matrix hardened by intermetallic phases generally have to be produced by powder metallurgy because of their high content of alloying elements. The objective of this investigation was the evaluation of powder metallurgical processing for an A16Fe powder alloy containing various fractions and volume contents of SiC particles. During processing, the effect of powder mixing on SiC particle distribution in the extruded pro...

  15. SiC nanocrystals as Pt catalyst supports for fuel cell applications

    DEFF Research Database (Denmark)

    Dhiman, Rajnish; Morgen, Per; Skou, E.M.

    2013-01-01

    A robust catalyst support is pivotal to Proton Exchange Membrane Fuel Cells (PEMFCs) to overcome challenges such as catalyst support corrosion, low catalyst utilization and overall capital cost. SiC is a promising candidate material which could be applied as a catalyst support in PEMFCs. Si...... based catalysts (BASF & HISPEC). These promising results signal a new era of SiC based catalysts for fuel cell applications. © The Royal Society of Chemistry 2013....

  16. Characterization and functionalization by sol–gel route of SiC foams

    OpenAIRE

    Mollicone, Jessica; Ansart, Florence; Lenormand, Pascal; Duployer, Benjamin; Tenailleau, Christophe; Jérôme VICENTE (LEREPS-GRES)

    2014-01-01

    International audience; Ceramic foam materials are commonly used for various applications, including catalyst supports or solar receivers. SiC foams are good candidates for the latter application as solar receivers. Its efficiency is directly related to the geometry, which can be evidenced by X-ray microtomography, and optical properties of the receiver. A promising route to add functionalities with homogenous and adhering oxide coatings onto complex SiC foams in a single step process is prop...

  17. Laser annealing of sputter-deposited -SiC and -SiCN films

    Indian Academy of Sciences (India)

    M A Fraga; M Massi; I C Oliveira; F D Origo; W Miyakawa

    2011-12-01

    This work describes the laser annealing of -SiC and -SiCN films deposited on (100) Si and quartz substrates by RF magnetron sputtering. Two samples of -SiCN thin films were produced under different N2/Ar flow ratios. Rutherford backscattering spectroscopy (RBS), Raman analysis and Fourier transform infrared spectrometry (FTIR) techniques were used to investigate the composition and bonding structure of as-deposited and laser annealed SiC and SiCN films.

  18. Manufacturing: SiC Power Electronics for Variable Frequency Motor Drives

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Kelsey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bench Reese, Samantha R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Remo, Timothy W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-15

    This brochure, published as an annual research highlight of the Clean Energy Manufacturing Analysis Center (CEMAC), summarizes CEMAC analysis of silicon carbide (SiC) power electronics for variable frequency motor drives. The key finding presented is that variations in manufacturing expertise, yields, and access to existing facilities impact regional costs and manufacturing location decisions for SiC ingots, wafers, chips, and power modules more than do core country-specific factors such as labor and electricity costs.

  19. Scalable SiC Power Switches for Applications in More Electric Vehicles (Preprint)

    Science.gov (United States)

    2007-06-01

    AFRL-PR-WP-TP-2007-237 SCALABLE SiC POWER SWITCHES FOR APPLICATIONS IN MORE ELECTRIC VEHICLES (PREPRINT) Michael S. Mazzola, Douglas Seale...SWITCHES FOR APPLICATIONS IN MORE ELECTRIC VEHICLES (PREPRINT) 5c. PROGRAM ELEMENT NUMBER 63175C 5d. PROJECT NUMBER 1168 5e. TASK NUMBER 13 6...Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18 1 Scalable SiC Power Switches for Applications in More Electric Vehicles Abstract

  20. Evaluation of surface recombination of SiC for development of bipolar devices

    Science.gov (United States)

    Kato, Masashi

    2016-09-01

    Ultra-high voltage power devices are employed for management of power networks. Si-based semiconductor devices have been developed for such the power devices. Maximum breakdown voltages of Si devices are of the order of kV. When the voltage in the power network was higher than the breakdown voltage of the devices, the devices were connected in series. The series connection introduces high resistance and power loss. To overcome this series resistance problem, it has been suggested that utilization of silicon carbide (SiC) devices. SiC has much higher breakdown electric field than Si, and thus high voltage in the power networks can be managed by SiC device without the series connection. Therefore, development of ultra-high voltage SiC device will decrease resistance and power loss in the power networks. However, there are several difficulties to develop ultra-high voltage SiC devices. One of the difficulties is control of the carrier lifetime. In fact, ultra-high voltage devices are fabricated with bipolar structure, and, in the bipolar devices, the carrier lifetime is highly influential on resistance and power loss. The carrier lifetime is limited by several factors, and one of the most important factors is the surface recombination. Therefore, evaluation and control of the surface recombination is essential to develop ultra-high voltage SiC devices. In this paper, we will report evaluation techniques for the surface recombination of SiC. In addition, dependence of the surface recombination on surface treatments, crystal faces and temperature are shown. The evaluated surface recombination velocities will support development of ultra-high voltage SiC devices.

  1. Blowing-machine representation of various meteorological situations for the study of rejection into the atmosphere; Essais de representation en soufflerie des diverses situations meteorologiques pour l'etude des rejets dans l'atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.Ph. [CEA Marcoule, Centre de Production de Plutonium, 30 (France)

    1964-07-01

    A stratified blowing-machine has been built making it possible to introduce into the tests a vertical temperature gradient. The similitude conditions have been examined. The development tests have made it possible to observe and to film the shape of the smoke pall emitted by a chimney in different cases. Stationary waves have been obtained in steady state conditions and the cross-section of the pall has also been studied. It appears that certain diffusion studies justify the use of a stratified blowing-machine. (author) [French] Une soufflerie stratifiee permettant d'introduire dans les experimentations le gradient vertical de la temperature a ete realisee. Les conditions de similitude ont ete examinees. Des essais de mise au point ont permis d'observer et de filmer l'allure du panache de fumee emis par une cheminee dans differents cas. La formation d'ondes stationnaires en regime stable a ete obtenue et la section droite du panache a ete egalement etudiee. Il apparait que certaines etudes de diffusion doivent justifier l'emploi d'une soufflerie stratifiee. (auteur)

  2. Lõuka tuuliku restaureerimine / Dan Lukas

    Index Scriptorium Estoniae

    Lukas, Dan

    2005-01-01

    Hiiumaal Pühalepa vallas Vahtrepa külas Lõuka talu maadel asuva pukktuuliku ajaloost, restaureerimise käigust. Teostus: Dan Lukas. Muinsuskaitseline järelevalve: Tõnu Sepp, tema kommentaar. Ill.:pukktuuliku lõiked ja korruste plaanid, 7 värv. fotot

  3. Corner Office: Google's Dan Clancy

    Science.gov (United States)

    Albanese, Andrew Richard; Oder, Norman

    2009-01-01

    This article presents an interview with Dan Clancy, engineering director for Google Book Search. In this interview, Clancy talks about the pending Google Book Search settlement, involving millions of volumes digitized from libraries, which drew a lawsuit from the Association of American Publishers and the Authors Guild. He also discusses pricing,…

  4. Corner Office: Google's Dan Clancy

    Science.gov (United States)

    Albanese, Andrew Richard; Oder, Norman

    2009-01-01

    This article presents an interview with Dan Clancy, engineering director for Google Book Search. In this interview, Clancy talks about the pending Google Book Search settlement, involving millions of volumes digitized from libraries, which drew a lawsuit from the Association of American Publishers and the Authors Guild. He also discusses pricing,…

  5. HUKUM DAN PERUBAHAN MASYARAKAT

    Directory of Open Access Journals (Sweden)

    Antoni Antoni

    2015-05-01

    Full Text Available Abstract: Where there is sugar there must be an ant, or likefish and water, as it were appropriate parable likens the Lawand Society, because where there is society there must be lawswill be needed. Law and society are two sides of which aredifficult to separate, because they will need each other andinfluence each other.ملخص:حیث یوجد السكر یجب أن یكون ھناك نملة، أو مثل السمك والماء، كما انھاكانت مناسبة المثل یشبھ القانون والمجتمع، وذلك لأن عندما یكون ھناك مجتمع یجبأن یكون ھناك وستكون ھناك حاجة القوانین .القانون والمجتمع وجھان لوالتي یصعبفصل، لأنھا سوف نحتاج إلى بعضنا البعض وتؤثر على بعضھا البعض.Kata Kunci: hukum dan perubahan masyarakat

  6. Mechanical Behavior of Sic Fiber-Sic Matrix Composite and Correlation to In Situ Fiber Properites at Room and High Temperatures

    Institute of Scientific and Technical Information of China (English)

    Shuqi Guo; Yutaka Kagawa

    2000-01-01

    @@ Tensile mechanical properties of PIP-processed 2D, plain-woven fabric. BN-coated Hi-NicalonTM SiC fiber-reinforced SiC matrix composite at room temperature (298 K), 1400 and 1600 K in air have been studied.Young's modulus and tensile strength of the composite decrease with the increase of test temperature, especially at 1600 K a considerable reduction is observed. The tensile strength is found to be consistent with the value predicted by a global load sharing model, based on the actual in situ fiber strength properties which are obtained by a fracture mirror method.

  7. Elaboration and characterization of luminescent porous SiC microparticles/poly vinyl alcohol thin films

    Science.gov (United States)

    Kaci, S.; Mansouri, H.; Bozetine, I.; Keffous, A.; Guerbous, L.; Siahmed, Y.; Aissiou, S.

    2017-02-01

    In this study, Morphological, optical and photoluminescence characterizations of nanostructured SiC micropowder embedded in PVA matrix and deposited as thin films on glass substrates are reported. we prepared the porous SiC microparticles/PVA thin films by spin coating method. The average size of SiC microparticles were 7 μm. An electroless method was used for producing porous silicon carbide powder under UV irradiation. Silver nanoparticles coated SiC powder was formed by polyol process. The etchant was composed of aqueous HF and different oxidants. Various porous morphologies were obtained and studied as a function of oxidant type, etching time, and wavelength of irradiation. We concluded that the chemical etching conditions of SiC powder seems to have a large impact on the resulting properties. We noticed that the best photoluminescence property was achieved when SiC powder was etched in HF/K2S2O8 at reaction temperature of 80 °C for t = 40min and under UV light of 254 nm.

  8. Electronic Structure and Chemical Bond of Ti3SiC2 and Adding Al Element

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; LU Ning; MEI Bingchu

    2006-01-01

    The relation among electronic structure, chemical bond and property of Ti3SiC2 and Al-doped was studied by density function and discrete variation (DFT-DVM) method. When Al element is added into Ti3SiC2, there is a less difference of ionic bond, which does not play a leading role to influent the properties. After adding Al, the covalent bond of Al and the near Ti becomes somewhat weaker, but the covalent bond of Al and the Si in the same layer is obviously stronger than that of Si and Si before adding. Therefore, in preparation of Ti3SiC2, adding a proper quantity of Al can promote the formation of Ti3SiC2. The density of state shows that there is a mixed conductor character in both of Ti3SiC2 and adding Al element. Ti3SiC2 is with more tendencies to form a semiconductor. The total density of state near Fermi lever after adding Al is larger than that before adding, so the electric conductivity may increase after adding Al.

  9. Effect of Ductile Agents on the Dynamic Behavior of SiC3D Network Composites

    Science.gov (United States)

    Zhu, Jingbo; Wang, Yangwei; Wang, Fuchi; Fan, Qunbo

    2016-10-01

    Co-continuous SiC ceramic composites using pure aluminum, epoxy, and polyurethane (PU) as ductile agents were developed. The dynamic mechanical behavior and failure mechanisms were investigated experimentally using the split Hopkinson pressure bar (SHPB) method and computationally by finite element (FE) simulations. The results show that the SiC3D/Al composite has the best overall performance in comparison with SiC3D/epoxy and SiC3D/PU composites. FE simulations are generally consistent with experimental data. These simulations provide valuable help in predicting mechanical strength and in interpreting the experimental results and failure mechanisms. They may be combined with micrographs for fracture characterizations of the composites. We found that interactions between the SiC phase and ductile agents under dynamic compression in the SHPB method are complex, and that interfacial condition is an important parameter that determines the mechanical response of SiC3D composites with a characteristic interlocking structure during dynamic compression. However, the effect of the mechanical properties of ductile agents on dynamic behavior of the composites is a second consideration in the production of the composites.

  10. Si/C hybrid nanostructures for Li-ion anodes: An overview

    Science.gov (United States)

    Terranova, Maria Letizia; Orlanducci, Silvia; Tamburri, Emanuela; Guglielmotti, Valeria; Rossi, Marco

    2014-01-01

    This review article summarizes recent and increasing efforts in the development of novel Li ion cell anode nanomaterials based on the coupling of C with Si. The rationale behind such efforts is based on the fact that the Si-C coupling realizes a favourable combination of the two materials properties, such as the high lithiation capacity of Si and the mechanical and conductive properties of C, making Si/C hybrid nanomaterials the ideal candidates for innovative and improved Li-ion anodes. Together with an overview of the methodologies proposed in the last decade for material preparation, a discussion on relationship between organization at the nanoscale of the hybrid Si/C systems and battery performances is given. An emerging indication is that the enhancement of the batteries efficiency in terms of mass capacity, energy density and cycling stability, resides in the ability to arrange Si/C bi-component nanostructures in pre-defined architectures. Starting from the results obtained so far, this paper aims to indicate some emerging directions and to inspire promising routes to optimize fabrication of Si/C nanomaterials and engineering of Li-ion anodes structures. The use of Si/C hybrid nanostructures could represents a viable and effective solution to the foreseen limits of present lithium ion technology.

  11. U.S. Department of Energy Accident Resistant SiC Clad Nuclear Fuel Development

    Energy Technology Data Exchange (ETDEWEB)

    George W. Griffith

    2011-10-01

    A significant effort is being placed on silicon carbide ceramic matrix composite (SiC CMC) nuclear fuel cladding by Light Water Reactor Sustainability (LWRS) Advanced Light Water Reactor Nuclear Fuels Pathway. The intent of this work is to invest in a high-risk, high-reward technology that can be introduced in a relatively short time. The LWRS goal is to demonstrate successful advanced fuels technology that suitable for commercial development to support nuclear relicensing. Ceramic matrix composites are an established non-nuclear technology that utilizes ceramic fibers embedded in a ceramic matrix. A thin interfacial layer between the fibers and the matrix allows for ductile behavior. The SiC CMC has relatively high strength at high reactor accident temperatures when compared to metallic cladding. SiC also has a very low chemical reactivity and doesn't react exothermically with the reactor cooling water. The radiation behavior of SiC has also been studied extensively as structural fusion system components. The SiC CMC technology is in the early stages of development and will need to mature before confidence in the developed designs can created. The advanced SiC CMC materials do offer the potential for greatly improved safety because of their high temperature strength, chemical stability and reduced hydrogen generation.

  12. Velcro-Inspired SiC Fuzzy Fibers for Aerospace Applications.

    Science.gov (United States)

    Hart, Amelia H C; Koizumi, Ryota; Hamel, John; Owuor, Peter Samora; Ito, Yusuke; Ozden, Sehmus; Bhowmick, Sanjit; Syed Amanulla, Syed Asif; Tsafack, Thierry; Keyshar, Kunttal; Mital, Rahul; Hurst, Janet; Vajtai, Robert; Tiwary, Chandra Sekhar; Ajayan, Pulickel M

    2017-04-05

    The most recent and innovative silicon carbide (SiC) fiber ceramic matrix composites, used for lightweight high-heat engine parts in aerospace applications, are woven, layered, and then surrounded by a SiC ceramic matrix composite (CMC). To further improve both the mechanical properties and thermal and oxidative resistance abilities of this material, SiC nanotubes and nanowires (SiCNT/NWs) are grown on the surface of the SiC fiber via carbon nanotube conversion. This conversion utilizes the shape memory synthesis (SMS) method, starting with carbon nanotube (CNT) growth on the SiC fiber surface, to capitalize on the ease of dense surface morphology optimization and the ability to effectively engineer the CNT-SiC fiber interface to create a secure nanotube-fiber attachment. Then, by converting the CNTs to SiCNT/NWs, the relative morphology, advantageous mechanical properties, and secure connection of the initial CNT-SiC fiber architecture are retained, with the addition of high temperature and oxidation resistance. The resultant SiCNT/NW-SiC fiber can be used inside the SiC ceramic matrix composite for a high-heat turbo engine part with longer fatigue life and higher temperature resistance. The differing sides of the woven SiCNT/NWs act as the "hook and loop" mechanism of Velcro but in much smaller scale.

  13. SiC fibre by chemical vapour deposition on tungsten filament

    Indian Academy of Sciences (India)

    R V Krishnarao; J Subrahmanyam; S Subbarao

    2001-06-01

    A CVD system for the production of continuous SiC fibre was set up. The process of SiC coating on 19 m diameter tungsten substrate was studied. Methyl trichloro silane (CH3SiCl3) and hydrogen reactants were used. Effect of substrate temperature (1300–1500°C) and concentration of reactants on the formation of SiC coating were studied. SiC coatings of negligible thickness were formed at very low flow rates of hydrogen (5 × 10–5 m3/min) and CH3SiCl3 (1.0 × 10–4 m3/min of Ar). Uneven coatings and brittle fibres were formed at very high concentrations of CH3SiCl3 (6 × 10–4 m3/min of Ar). The flow rates of CH3SiCl3 and hydrogen were adjusted to get SiC fibre with smooth surface. The structure and morphology of SiC fibres were evaluated.

  14. Feasibility study on the application of carbide (ZrC, SiC) for VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Yeon; Kim, Weon Ju; Jung, Choong Hwan; Ryu, Woo Seog; Kim, Si Hyeong; Jang, Moon Hee; Lee, Young Woo

    2006-08-15

    A feasibility study on the coating process of ZrC for the TRISO nuclear fuel and applications of SiC as high temperature materials for the core components has performed to develop the fabrication process for the advanced ZrC TRISO fuels and the high temperature structural components for VHTR, respectively. In the case of ZrC coating, studies were focused on the comparisons of the developed coating processes for screening of our technology, the evaluations of the reactions parameters for a ZrC deposition by the thermodynamic calculations and the preliminary coating experiments by the chloride process. With relate to SiC ceramics, our interesting items are as followings; an analysis of applications and specifications of the SiC components and collections of the SiC properties and establishments of data base. For these purposes, applications of SiC ceramics for the GEN-IV related components as well as the fusion reactor related ones were reviewed. Additionally, the on-going activities with related to the ZrC clad and the SiC composites discussed in the VHTR GIF-PMB, were reviewed to make the further research plans at the section 1 in chapter 3.

  15. Packaging Technologies for 500C SiC Electronics and Sensors

    Science.gov (United States)

    Chen, Liang-Yu

    2013-01-01

    Various SiC electronics and sensors are currently under development for applications in 500C high temperature environments such as hot sections of aerospace engines and the surface of Venus. In order to conduct long-term test and eventually commercialize these SiC devices, compatible packaging technologies for the SiC electronics and sensors are required. This presentation reviews packaging technologies developed for 500C SiC electronics and sensors to address both component and subsystem level packaging needs for high temperature environments. The packaging system for high temperature SiC electronics includes ceramic chip-level packages, ceramic printed circuit boards (PCBs), and edge-connectors. High temperature durable die-attach and precious metal wire-bonding are used in the chip-level packaging process. A high temperature sensor package is specifically designed to address high temperature micro-fabricated capacitive pressure sensors for high differential pressure environments. This presentation describes development of these electronics and sensor packaging technologies, including some testing results of SiC electronics and capacitive pressure sensors using these packaging technologies.

  16. Applications, Prospects and Challenges of Silicon Carbide Junction Field Effect Transistor (SIC JFET

    Directory of Open Access Journals (Sweden)

    Frederick Ojiemhende Ehiagwina

    2016-09-01

    Full Text Available Properties of Silicon Carbide Junction Field Effect Transistor (SiC JFET such as high switching speed, low forward voltage drop and high temperature operation have attracted the interest of power electronic researchers and technologists, who for many years developed devices based on Silicon (Si.  A number of power system Engineers have made efforts to develop more robust equipment including circuits or modules with higher power density. However, it was realized that several available power semiconductor devices were approaching theoretical limits offered by Si material with respect to capability to block high voltage, provide low on-state voltage drop and switch at high frequencies. This paper presents an overview of the current applications of SiC JFET in circuits such as inverters, rectifiers and amplifiers. Other areas of application reviewed include; usage of the SiC JFET in pulse signal circuits and boost converters. Efforts directed toward mitigating the observed increase in electromagnetic interference were also discussed. It also presented some areas for further research, such as having more applications of SiC JFET in harsh, high temperature environment. More work is needed with regards to SiC JFET drivers so as to ensure stable and reliable operation, and reduction in the prices of SiC JFETs through mass production by industries.

  17. A SiC MOSFET Based Inverter for Wireless Power Transfer Applications

    Energy Technology Data Exchange (ETDEWEB)

    Onar, Omer C [ORNL; Chinthavali, Madhu Sudhan [ORNL; Campbell, Steven L [ORNL; Ning, Puqi [Chinese Academy of Sciences (CAS); White, Cliff P [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC

    2014-01-01

    In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at three center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.

  18. Transport de particules massives dans un fluide turbulent: Application a l'erosion due au sable sur les parois d'une turbine hydraulique

    Science.gov (United States)

    Bergeron, Stephen

    Le transport de particules massives par un champ turbulent est un vaste domaine de la mécanique des fluides. Il possède de nombreuses applications comme par exemple le transport de sable dans une turbine hydraulique. En raison de la dureté des grains de quartz et des grandes vitesses de collision avec les parois métalliques, un phénomène d'érosion intensif se produit. Les dommages résultants peuvent diminuer le rendement de la turbine au cours des quelques mois suivant la mise en opération. L'objectif de cette thèse est de mettre au point un outil permettant de prédire ces zones d'érosion. Ce projet de recherche en contexte industriel a été réalisé en collaboration avec la compagnie General Electric Hydro du Canada. Dans un régime hautement turbulent, il est possible d'obtenir une expression suffisamment générale en utilisant une formulation partiellement empirique: l'équation de Basset- Boussinesq-Oseen modifiée. Ce choix de modèle tient compte du niveau de précision recherché et de la méthode numérique employée afin de résoudre la phase fluide. Il permet aussi d'éliminer plusieurs ambiguïtés fréquemment rencontrées dans la littérature et implementées dans certains codes commerciaux courants. La formulation mathématique du problème est effectuée dans un espace mixte Euler-Lagrange. Les paramètres dynamiques sont relies au type de particules et à l'intensité de la turbulence. Le code numérique résultant est le plus performant développé à ce jour (août 1998). Les trajectoires de plusieurs centaines de milliers de particules peuvent être simulées et visualisées de manière interactive sur une station de travail (SGI R4K, R8K et R10K). L'utilisateur du logiciel est libre de se déplacer dans l'espace à l'aide d'un environnement similaire a un ``simulateur de vol''. Il peut ainsi analyser les détails du processus d'érosion de même que l'écoulement du fluide dans la turbine. Les zones d'érosion obtenues à l

  19. Incorporation of oxygen in SiC implanted with hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Barcz, A., E-mail: barcz@ite.waw.pl [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Institute of Electron Technology, 02-668 Warsaw (Poland); Jakieła, R. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Kozubal, M. [Institute of Electron Technology, 02-668 Warsaw (Poland); Dyczewski, J. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Celler, G.K. [Institute for Advanced Materials, Devices, and Nanotechnology (IAMDN)/Department of Materials Science and Engineering, Rutgers University, New Brunswick, NJ 08901 (United States)

    2015-12-15

    Oxygen accumulation at buried implantation-damage layers was studied after post-implantation annealing of hydrogen- or deuterium-implanted 4H–SiC. In this study H{sup +} or {sup 2}H{sup +} implantation was carried out at energies E, from 200 keV to 1 MeV, to fluences D, ranging from 2 × 10{sup 16}/cm{sup 2} to 1 × 10{sup 17}/cm{sup 2}. For comparison, the implantation was also done into float-zone (FZ) and Czochralski (CZ) silicon wafers. Post-implantation annealing at temperatures from 400 °C to 1150 °C was performed either in pure argon or in a water vapor. Characterization methods included SIMS, RBS and TEM. At sufficiently high doses, hydrogen implantation into semiconductors leads to the irreversible formation of a planar zone of microcavities, bubbles and other extended defects located at the maximum of deposited energy. This kind of highly perturbed layer, containing large amounts of agglomerated hydrogen is known to efficiently getter a number of impurities. Oxygen was detected in both CZ and FZ silicon subjected to Smart-Cut™ processing. We have identified, by SIMS profiling, a considerable oxygen peak situated at the interface between the SiC substrate and a layer implanted with 1 × 10{sup 17} H ions/cm{sup 2} and heated to 1150 °C in either H{sub 2}O vapor or in a nominally pure Ar. In view of a lack of convincing evidence that a hexagonal SiC might contain substantial amounts of oxygen, the objective of the present study was to identify the source and possible transport mechanism of oxygen species to the cavity band. Through the analysis of several implants annealed at various conditions, we conclude that, besides diffusion from the bulk or from surface oxides, an alternative path for oxygen agglomeration is migration of gaseous O{sub 2} or H{sub 2}O from the edge of the sample through the porous layer.

  20. Gangguan Fungsi Penghidu dan Pemeriksaannya

    Directory of Open Access Journals (Sweden)

    Effy Huriyati

    2014-01-01

    Full Text Available AbstrakLatar belakang: Fungsi penghidu pada manusia memegang peranan penting. Gangguan penghidu dapat mempengaruhi keselamatan dan kualitas hidup seseorang. Tujuan: Untuk mengetahui jenis gangguan penghidu, penyebab gangguan penghidu, dan pemeriksaannya. Tinjauan Pustaka: Gangguan penghidu dapat berupa anosmia yaitu hilangnya kemampuan penghidu, atau hiposmia yaitu berkurangnya kemampuan penghidu. Gangguan penghidu disebabkan gangguan konduksi, gangguan sensoria dan gangguan neural. Penyakit tersering penyebab gangguan penghidu yaitu rinosinusitis kronis, rinitis alergi, infeksi saluran nafas atas dan trauma kepala. Ada beberapa modalitas pemeriksaan kemosensoris fungsi penghidu diantaranya Tes “Sniffin sticks”. Dengan tes „Sniffin sticks” dapat diketahui ambang penghidu, diskriminasi penghidu dan identifikasi penghidu seseorang. Kesimpulan: Gangguan penghidu memerlukan perhatian khusus. Diantara beberapa modalitas pemeriksaan kemosensoris penghidu, tes “Sniffin sticks” mempunyai beberapa kelebihan.Kata kunci: Gangguan penghidu, anosmia, hiposmia, tes “Sniffin sticks”.AbstractBackground: Olfactory function in humans plays an important role. Olfactory disorders can affect the safety and quality of life. Objective: To determine the type of olfactory disorder, the causes of olfactory disorders, and the examination. Literature Review: Olfactory disorder can be not smell anything or anosmia, and reduced of smell or hyposmia. Olfactory disorders caused by conduction disturbances, neural disturbances and sensoris disturbances. Disease that often causes disturbances of olfactory function is, chronic rhinosinusitis, allergic rhinitis, upper respiratory tract infections and head trauma. There are several modalities to examine chemosensoris smelling function, one of them is “Sniffin sticks” test. This test can examine threshold, discrimination, and identification of smelling. Conclusions: Impaired smelling require special attention

  1. PEMBINAAN DAN PENGEMBANGAN USAHA KECIL

    Directory of Open Access Journals (Sweden)

    Sentot Harman Glendoh

    2001-01-01

    Full Text Available Small business as an economic activity of society on a small scale, has a central role in the economy of Indonesia. Although the economic crisis has created a great disturbance in the live of large and middle-size business, apparently small business continues to function well in the lower levels of the economy. The main role of small business is: 1 use excess labor; 2 as a producer of goods and services at reachable prices for the lower economic levels of society; 3 as a potential producer of foreign exchange because of the success of this type of industry in producing non-oil commodities for export. Remembering that the role of small business is large and has great influence on the lower economic levels of society, it is quite necessary to pay attention to the development of this sector. Abstract in Bahasa Indonesia : Usaha kecil sebagai kegiatan ekonomi rakyat berskala kecil memiliki peran sentral dalam perekonomian Indonesia. Walaupun krisis ekonomi telah memporakporandakan kehidupan bidang usaha besar dan menengah, ternyata usaha kecil tetap tegar dan berjalan marak dikawasan kehidupan ekonomi tingkat bawah. Peran pokok usaha kecil ini adalah: (1 sebagai penyerap tenaga kerja, (2 sebagai penghasil barang dan jasa pada tingkat harga yang terjangkau bagi kebutuhan rakyat banyak yang berpenghasilan rendah, (3 sebagai penghasil devisa negara yang potensial kerena keberhasilannya dalam meproduksi komoditi ekspor non migas. Mengingat peran usaha kecil tersebut sangat besar andilnya bagi negara dan masyarakat kecil dilapisan bawah, maka pembinaan dan pengembangannya sangat perlu diperhatikan. Kata kunci: pembinaan, pengembangan, usaha kecil.

  2. KINERJA DAN EFISIENSI BANK PEMERINTAH (BUMN DAN BUSN YANG GO PUBLIK DI INDONESIA

    Directory of Open Access Journals (Sweden)

    Sugeng Haryanto

    2012-06-01

    Full Text Available Penelitian ini menganalisis kinerja dan tingkat efisiensi bank-bank BUMN dan BUSN yang go Publik di Bursa Efek Indonesia.  Sample penelitian ini mengambil  tiga bank BUMN Bank BNI 46, Bank Mandiri dan Bank BRI  dan tiga bank BUSN (Bank BCA, Bank Niaga dan Bank Panin dengan periode analisis tahun 2005-2011. Varibael yang digunakan meliputi ROA, ROE, LAR. LDR, NPL dan BOPO. Tujuan dari penelitian ini adalah melihat dan menganalisis perbedaan kinerja antara Bank BUMN dan BUSN yang go public di Bursa Efek Indonesia tahun 2005-2011.  Pendekatan pengukuran kinerja yang digunakan adalah Return on Asset (ROA, Return on Equity (ROE dan Loan to Deposit Ratio (LDR, Loan to Asset Ratio (LAR,  dan efisiensi bank. Hasil dari penelitian menunjukkan bahwa 1 Bank-bank nasional, baik itu bank BUMN maupun BUSN menunjukkan kinerja yang semakin baik, 2 tidak terdapat perbedaan yang signifikan antara kinerja bank BUMN dan BUSN untuk variabel ROA, ROE, LAR, LDR, dan BOPO sedangkan variabel NPL yang merupakan indikator risiko kredit menunjukkan adanya perbedaan yang signifikan antara Bank BUMN dan BUSN

  3. AGROFORESTRI UNTUK ADAPTASI DAN MITIGASI PERUBAHAN IKLIM

    Directory of Open Access Journals (Sweden)

    Tigor Butarbutar

    2017-01-01

    Full Text Available Hilangnya tutupan lahan hutan karena konversi hutan untuk pemukiman, perkebunan, pertanian dan kebutuhan untuk pembangunan di sektor lain, telah menyebabkan perubahan pola cuaca/iklim di berbagai tempat. Perubahan iklim dapat diantisipasi dengan mitigasi dan adaptasi. Mitigasi berarti usahausaha pencegahan yang perlu dilakukan, sedangkan adaptasi merupakan kegiatan-kegiatan penyesuaian yang perlu dilakukan untuk dapat hidup dan bertahan dan meningkatkan ketahanan, kelenturan dan mengarahkemigrasikarenakondisiiklimyangberbeda.Agroforestridapatmemitigasidanmengadaptasi perubahaniklim dengan alasan-alasansebagaiberikut: aPencampuranjenis pohonpenghasilkayu,buah dan lain-lain, karena campuran jenis lebih baik dari tanaman murni; b Pencampuran jenis yang didasarkan pada sifat toleransi ( dan , sehingga akan memanfaatkan seluruh cahaya untuk fotosintesis; c Pencampuran perbedaan umur; d Pencampuran berdasarkan perbedaan waktu pemanenan; e Penggabungan nilai ekonomi, sosial dan budaya sehingga perubahan vegetasi dapat berjalan seiring dengan perubahan sosial dan budaya secara berangsur yang dapat disesuaikan dengan perubahan iklim; dan f Dapat digunakan sebagai model untuk memfasilitasi perubahan kelompok vegetasi menjadi kelompok yang baru (adaptasi, seperti teori perubahan vegetasi melalui perladangan berpindah-pindahyangteratur.

  4. INDUSTRIALISASI DAN TANTANGANNYA PADA SEKTOR PENDIDIKAN

    Directory of Open Access Journals (Sweden)

    Arif Unwanullah

    2015-10-01

    Full Text Available Abstrak: Industrialisasi dan Tantangannya pada Sektor Pendidikan. Sumbangan pendidikan dalam perubahan dan pembangunan masa lalu telah bergeser dengan kemajuan teknoekonomi dan komunikasi. Perubahan yang terjadi telah menggeser tatanan kehidupan dan pandangan masyarakat. Materialisme, kapitalisme, efisiensi, dan efektivitas telah menjadi tujuan dan semangat hidup. Pergeseran pandangan masyarakat telah mengubah pula pandangan keberhasilan dan mutu pendidikan, di mana pendidikan diukur dari keberhasilan dalam keterserapan lulusan dalam dunia kerja, oleh karenanya pendidikan dianalisis dari karakteristik sebagai investasi (capital-investment. Pergeseran makna dan tanggung jawab pendidikan mendorong dunia pendidikan melakukan pembaruan dengan alternatif: membangun pembaruan penalaran warganya menuju pemerdekaan dan pendewasaan, pendidikan dilaksanakan secara komprehensif dan bekerjasama dengan semua pihak secara kemitraan, dan membangun visi pendidikan secara komprehensif dan simultan dengan semua pihak. Kata kunci: perubahan sosial, materialistik, modernisasi dan kapitalis Abstract: Industrialization and its education Sector challenges. Contribution of education has shifted with the progress of technology, economy, and communication. The changes have shifted the society's views. Materialism, capitalism, efficiency, and effectiveness have become of interest and enthusiasm for life. The shift has changed society's view, i.e. the view of success and quality of education, in which education is measured from a rate of the absorption of graduates into labor market, therefore education is analyzed from the characteristics of an investment (capital-investment. A shift in meaning and responsibility of education encourages the education sector to create reformation through these following alternatives: creating new thoughts towards liberation and maturation, implementing education comprehensively and cooperating with all parties in partnership, and creating

  5. Electronic Structure of SiC(310)Twin Boundary Doped With B,N,Al and Ti

    Institute of Scientific and Technical Information of China (English)

    YE Yajing; ZHANG Litong; SU Kehe; CHENG Laifei; XU Yongdong

    2009-01-01

    Doping of boron,nitrogen,aluminum and titanium in the SiC(310)twin boundary was investigated,and the first-principle calculation was used to analyze the underlying mechanism of excellent creep resistance and strength of Sylramic and Tyranno SA SiC fibers.The electronic struc-tures were also analyzed and compared.The results of Mulliken overlap populations,electron density differences and density of states reveal that doping of B or N atom reinforces SiC GBs bonding, however,doping of Al or Ti atom weakens SiC GBs bonding.The reinforced SiC GBs will largely prevent atoms from sliding near GBs.The experimental results would be one of the reasons which lead to the reinforcement of either creep resistance or the strength of SiC fibers.

  6. Microwave Absorption Properties of Ni-Foped SiC Powders in the 2-18 GHz Frequency Range

    Science.gov (United States)

    Jin, Hai-Bo; Li, Dan; Cao, Mao-Sheng; Dou, Yan-Kun; Chen, Tao; Wen, Bo; Simeon, Agathopoulos

    2011-03-01

    Ni-doped SiC powder with improved dielectric and microwave absorption properties was prepared by self-propagating high-temperature synthesis (SHS). The XRD analysis of the as-synthesized powders suggests that Ni is accommodated in the sites of Si in the lattice of SiC, which shrinks in the presence of Ni. The experimental results show an improvement in the dielectric properties of the Ni-doped SiC powder in the frequency range of 2-18 GHz. The bandwidth of the reflection loss below -10 dB is broadened from 3.04 (for pure SiC) to 4.56 GHz (for Ni-doped SiC), as well as the maximum reflection loss of produced powders from 13.34 to 22.57 dB, indicating that Ni-doped SiC could be used as an effective microwave absorption material.

  7. Microwave Absorption Properties of Ni-Foped SiC Powders in the 2-18 GHz Frequency Range

    Institute of Scientific and Technical Information of China (English)

    JIN Hai-Bo; LI Dan; CAO Mao-Sheng; DOU Yan-Kun; CHEN Tao; WEN Bo; Simeon Agathopoulos

    2011-01-01

    Ni-doped SiC powder with improved dielectric and microwave absorption properties was prepared by selfpropagating high-temperature synthesis(SHS). The XRD analysis of the asynthesized powders suggests that Ni is accommodated in the sites of Si in the lattice of SiC, which shrinks in the presence of Ni. The experimental results show an improvement in the dielectric properties of the Ni-doped SiC powder in the frequency range of 2-18 GHz. The bandwidth of the reflection loss below-10 dB is broadened from 3.04(for pure SiC) to 4.56 GHz (for Ni-doped SiC), as well as the maximum reflection loss of produced powders from 13.34 to 22.57dB, indicating that Ni-doped SiC could be used as an effective microwave absorption material.

  8. Amplifiers dedicated for large area SiC photodiodes

    Science.gov (United States)

    Doroz, P.; Duk, M.; Korwin-Pawlowski, M. L.; Borecki, M.

    2016-09-01

    Large area SiC photodiodes find applications in optoelectronic sensors working at special conditions. These conditions include detection of UV radiation in harsh environment. Moreover, the mentioned sensors have to be selective and resistant to unwanted signals. For this purpose, the modulation of light at source unit and the rejection of constant current and low frequency component of signal at detector unit are used. The popular frequency used for modulation in such sensor is 1kHz. The large area photodiodes are characterized by a large capacitance and low shunt resistance that varies with polarization of the photodiode and can significantly modify the conditions of signal pre-amplification. In this paper two pre-amplifiers topology are analyzed: the transimpedance amplifier and the non-inverting voltage to voltage amplifier with negative feedback. The feedback loops of both pre-amplifiers are equipped with elements used for initial constant current and low frequency signals rejections. Both circuits are analyzed and compared using simulation and experimental approaches.

  9. Development of Cu Reinforced SiC Particulate Composites

    Science.gov (United States)

    Singh, Harshpreet; Kumar, Lailesh; Nasimul Alam, Syed

    2015-02-01

    This paper presents the results of Cu-SiCp composites developed by powder metallurgy route and an attempt has been made to make a comparison between the composites developed by using unmilled Cu powder and milled Cu powder. SiC particles as reinforcement was blended with unmilled and as-milled Cu powderwith reinforcement contents of 10, 20, 30, 40 vol. % by powder metallurgy route. The mechanical properties of pure Cu and the composites developed were studied after sintering at 900°C for 1 h. Density of the sintered composites were found out based on the Archimedes' principle. X-ray diffraction of all the composites was done in order to determine the various phases in the composites. Scanning electron microscopy (SEM) and EDS (electron diffraction x-ray spectroscopy) was carried out for the microstructural analysis of the composites. Vickers microhardness tester was used to find out the hardness of the samples. Wear properties of the developed composites were also studied.

  10. MuSIC: delivering the world's most intense muon beam

    CERN Document Server

    Cook, S; Edmonds, A; Fukuda, M; Hatanaka, K; Hino, Y; Kuno, Y; Lancaster, M; Mori, Y; Ogitsu, T; Sakamoto, H; Sato, A; Tran, N H; Truong, N M; Wing, M; Yamamoto, A; Yoshida, M

    2016-01-01

    A new muon beamline, muon science innovative channel (MuSIC), was set up at the Research Centre for Nuclear Physics (RCNP), Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid the first $36^\\circ$ of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beamline. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively-charged muons, the X-ray spectrum yielded by muonic atoms in the target were measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded $(10.4 \\pm 2.7) \\times 1...

  11. IMPLEMENTASI KEBIJAKAN PEMUNGUTAN PAJAK BUMI DAN BANGUNAN

    Directory of Open Access Journals (Sweden)

    Arifuddin - Sahabu

    2012-05-01

    Full Text Available ABSTRAKS   Penelitian ini menggunakan metode kualitatif dengan bentuk studi kasus. Pengumpulan data dilakukan dengan menggunakan teknik wawancara, dokumentasi, dan observasi. Analisis data mengunakan metode analisis Miles dan Huberman, dengan melalui tiga prosedur yaitu reduksi data, penyajian data dan menarik kesimpulan/verifikasi. Sedangkan keabsahan menggunakan teknik berdasarkan atas kriteria derajat kepercayaan, keteralihan, ketergantungan, dan kepastian suatu data. Tuntutan menghadapi  implementasi Otonomi Daerah mengandung arti pentingnya Pemerintah Daerah memperhatikan kemampuan “self suporting” dalam bidang keuangan. Sumber pendapatan daerah tidak hanya di peroleh dari Pendapatan Asli Daerah, tetapi juga berupa pemberian bagi hasil dari penerimaan Pemerintah Pusat. Diantara sumber penerimaan tersebut adalah Pajak Bumi dan Bangunan. Dalam Undang-undang Nomor 25 Tahun 1999 Tentang perimbangan keuangan antara Pemerintah Pusat  dan Daerah, diantaranya dijelaskan bahwa sumber penerimaan daerah dalam penyelenggaraan desentralisasi berasal dari dana perimbangan penerimaan Pajak Bumi dan Bangunan disamping pemberian Dana Alokasi Umum dan Alokasi Khusus. Langkah Implementasi dari pelaksanan pemungutan Pajak Bumi dan Bangunan tersebut dilakukan Departemen Keuangan melalui Kantor Pelayanan Pajak Bumi dan Bangunan, sedang Pemerintah daerah menerima pelimpahan penagihan pada Sektor Perkotaan dan Sektor Pedesaan. Meskipun telah ada pelimpahan kewenangan kepada daerah, akan tetapi pelimpahan kewenangan tersebut terbatas pada mekanisme penagihan saja, sedang implementor yang menyangkut masalah administrasi masih berada pada Kantor Pelayan Pajak Bumi dan Bangunan. Kondisi demikian ini ditambah dengan kurangnya koordinasi antara unit organisasi pelaksana menyebabkan setiap tahun terjadi tunggakan. Sebagai sandaran teoritik utama  untuk mendiskripsikan serta menganalisis hambatan-hambatan implementasi kebijakan publik (dalam hal ini pemungutan

  12. TRANSFORMASI ORGANISASIONAL DAN MSDM: HAMBATAN DAN IMPLIKASINYA PADA REKRUTMEN DAN SELEKSI

    Directory of Open Access Journals (Sweden)

    Licen Indahwati Darsono

    2002-01-01

    Full Text Available Rapid change of environment is an external force that causes the organization to transform. Fundamentally, the main purpose of the transformation is to change the organizational structure to be more flexible and competitive with fewer hierarchial levels, managers, and employees. The transformation needs to be radical, causing resistance from the organization's members. Their resistance can cause the transformation to fail, therefore organization must find ways to lessen this resistance. First, organization must learn about the diversity of its members' cultures and values. Second, organization must build its own organizational culture which can support the success of the transformation, by communicating it with the members of the organization. To support organizational culture building efforts, it needs changes in human resources practices, especially recruitment and selection. Abstract in Bahasa Indonesia : Perubahan yang cepat dalam lingkungan merupakan kekuatan eksternal yang mengakibatkan transformasi dalam sebuah organisasi. Pada dasarnya, tujuan utama dari transformasi tersebut adalah merubah struktur organisasi agar menjadi lebih fleksibel dan mampu bersaing, dengan tingkat structural yang sedikit, serta jumlah manajer dan karyawan yang lebih kecil. Transformasi tersebut harus menyeluruh, dan hal ini dapat menyebabkan resistensi dari para anggota organisasi yang memperhambat perubahan tersebut. Resistensi itu bisa menyebabkan perubahan tersebut batal, oleh karena itu organisasi harus mencari jalan untuk mengurangi hambatan-hambatan tersebut. Pertama, organisasi harus belajar keanekaragaman dari budaya dan nilai anggotanya. Kedua, organisasi harus mengembangkan budaya organisasi sendiri melalui komunikasi yang baik dengan anggotanya. Untuk mendukung usaha mengembangkan budaya organisasi, harus ada perubaban pada kebijakan sumber daya manusia, terutama dalam rekrutmen dan seleksi karyawan. Kata kunci: transformasi, resistensi, budaya

  13. VAKSIN DENGUE DAN PERKEMBANGANNYA SAAT INI DAN DI MASA MENDATANG

    Directory of Open Access Journals (Sweden)

    Triwibowo Ambar Garjito

    2012-09-01

    Full Text Available Dengue virus merupakan salah satu virus anggota dari famili Flaviviridae yang sejak tahun 1956 telah dikenal dapat menimbulkan demam dengue maupun demam berdarah dengue (DBD. Penyakit yang ditularkan oleh nyamuk Aedes aegypti ini diperkirakan telah menjangkiti pada selatar 50-100 juta manusia dengan 500.000 kasus di antaranya dalam manifestasi yang ganas yang dikenal sebagai dengue haemorrhagic fever dan dengue shock syndrome dan 25.000 di antaranya berakibat fatal (meninggal. Saat ini pengembangan vaksin merupakan salah satu solusi yang diharapkan dapat menekan penyebaran penyakit tersebut. E (envelope merupakan salah satu bagian dari protein struktural virus yang sangat penting dalam pengembangan vaksin, yaitu sebagai badan yang memproduksi antibodi netralisasi untuk protein. Non-struktural protein l juga telah diketahui sebagai salah satu komponen penting dalam pengembangan vaksin oleh karena kemampuannya untuk dapat diekspresi pada permukaan sel yang diinfeksi yang dapat menjadi target untuk immune cytolisis. Ada dua pendekatan yang digunakan dalam memproduksi suatu vaksin dengue, yaitu: a. Vaksin hidup yang telah dilemahkan (live attenuated vaccine: b. Vaksin hasil rekayasa (engineered vaccine. Penelitian terhadap vaksin DENV baik rekombinan maupun non-rekombinan yang didasarkan pada uji virus telah dilakukan secara terus-menerus baik pada monyet dan manusia. Sampai saat ini telah dikembangkan sejumlah kandidat vaksin DENV yang berdasar pada tetravalent virus dengue, yaitu a. vaksin konvensional, b. vaksin dengue rekombinan berdasar pada flavivirus, c. vaksin intertypic chimeric, d. vaksin chimerivac, e. vaksin dengue rekombinan menggunakan vector non-ftavivirus dan f. vector adenovirus. Namun demikian, sampai sekarang belum ada vaksin yang siap digunakan untuk menangkal infeksi ke empat serotype virus dengue, sehingga masih diharapkan untuk pengembangan virus lebih lanjut.   Kata kunci: Aedes aegypti, dengue virus, vaksin dengue.

  14. Muhammad sebagai pemimpin agama dan negara periode Makkah dan Madinah

    Directory of Open Access Journals (Sweden)

    Ummu Zakiyah Maulidah

    2014-07-01

    Full Text Available Muhammad was born in Mecca between AD 570 and 580 in the Banu Hashims,a reputable family of Quraysh. In Mecca, Muhammad is portrayed as a privatecitizen, as he had to limit himself and adapt his behavior to face the situationduring jahiliyyah era. While, in Medina he governed the community and guidedthem in religious life. His arrival in Medina has significant contribution towardhis role as political leader. His power in this city had protected himself and hisfollowers from violent opposition of the Quraysh. The doctrines he employedin politics were inseparable from the religious values rooted from the Quran.Through his innovation and skillful diplomacy, he had converted the peopleof Mecca and Medina into brighter Arab civilization. Such a positive changereflected his monumental accomplishment for the people.Muhammad lahir di kota Makkah antara tahun 570 sampai 580 Masehi dikeluarga Bani Hasyim, suku Quraisy terkemuka di Arab. Di kota Makkah,Muhammad dianggap sebagai masyarakat biasa, sebab ia harus membatasidirinya dan menyesuaikan prilakunya dalam menghadapi keadaan yangterjadi pada zaman jahiliyyah. Sedangkan di Madinah, ia dianggap sebagaipemimpin masyarakat dan menjadi pembimbing umat dalam hidup beragama.Kedatangannya di Madinah juga memberikan konstribusi besar pada perannyasebagai pemimpin politik. Kekuasaan di kota ini sangat membantu dirinya danpara pengikutnya dari kerasnya kelompok oposisi Quraisy. Doktin-doktrin yangdigunakan Muhammad dalam dunia politik juga tidak lepas dari nilai-nilaiagama yang bersumber dari al Quran. Dengan kreatifitas dan inovasinya dalammemimpin, Muhammad mampu mengarahkan masyarakat Makkah dan Madinah menuju kebangkitan peradaban bangsa Arab yang lebih cemerlang.Kondisi yang semakin membaik tersebut, tidak lain merupakan sebuah karyadan jasa monumental yang telah diukir oleh Muhammad untuk umatnya.

  15. Matrix-grain-bridging contributions to the toughness of SiC composites with alumina-coated SiC platelets

    Energy Technology Data Exchange (ETDEWEB)

    Cao, J.J.; He, Y.; MoberlyChan, W.J.; De Jonghe, L.C. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley Lab., CA (United States). Materials Science Div.

    1996-05-01

    Silicon carbide composites were fabricated through the incorporation of alumina-coated SiC platelets into a SiC matrix. Mechanical properties were evaluated in direct comparison with a commercial Hexoloy SiC. The fracture toughness of the composite, with a fine grained {beta}-SiC matrix, was twice that of the commercial material. The alumina-coating on the platelets provided a weak interface to promote crack deflection and platelet bridging, as well as easing densification of the composites. On the other hand, a three-fold increase in fracture toughness (9.1 MPa {radical}m) of an in situ toughened monolithic SiC was achieved by processing at higher temperatures, promoting the {beta}-to-{alpha} phase transformation and forming a microstructure containing high-aspect-ration plate-shaped grains. Efforts were made to combine the effects of coated-platelets reinforcement and in situ toughening in the matrix. Moderate high toughness (8 MPa {radical}m) was achieved by coupled toughening. The contribution of matrix-grain-bridging, however, was limited by the processing temperature at which the oxide coating was stable.

  16. KONTEKS DAN KONSTRUKSI SOSIAL MENGENAI KEMATIAN ELEKTIF ( EUTHANASIA ∗

    Directory of Open Access Journals (Sweden)

    Helly Prajitno Soetjipto

    2015-09-01

    konteks sosial dan konstruksi sosial kematian. Euthanasia didiskusikan di dalam suatu kerangka pikir yang mencoba memberi perhatian kepada hal-hal yang kontekstual dan interpretatif fenomena sosial suatu proses kematian dan kejadian kematian

  17. PERJANJIAN SEWA GUNA USAHA ANTARA LESSEE DAN LESSOR

    Directory of Open Access Journals (Sweden)

    Aprilianti Aprilianti

    2014-03-01

    Full Text Available Perjanjian sewa guna usaha (leasing yang diadakan oleh Lessor dan Lesseen dilakukan secara tertulis dalam bentuk perjanjian standar. Isi perjanjian tersebut ditentukan oleh jenis dari leasing itu sendiri dan hubungan hukum (hak dan kewajiban timbal balik antara Lessor dan Lessee. Bagi Lessor, hak dan kewajibannya adalah memperoleh pembayaran sebagai imbalan jasa dan menyerahkan barang modal kepada Lessee. Sedangkan hak dan kewajiban Lessee adalah meperoleh kegunaan dari barang modal dan membayar sewa secara berkala. Tidak dipenuhinya hak dan kewajiban masing-masing pihak maka dapat disebut wanprestasi. Perjanjian akan berakhir jika hak dan kewajiban Lessor dan Lessee telah dilaksanakan sesuai dengan perjanjian. Kata Kunci: Leasing, Lessor, Lessee, hak dan kewajiban.

  18. Pembuatan Dan Karakterisasi Papan Partikel Peredam Suara Dari Campuran Resin Poliester Dan Jerami Padi

    OpenAIRE

    Marjuki, Ismail

    2013-01-01

    060802033 Telah dilakukan penelitian papan partikel dari jerami padi yang direaksikan dengan polyester tak jenuh yukalac 157 BQTN ? EX menggunakan katalis mepoxe. Papan partikel ini dibuat dengan proses pencampuran dengan perbandingan antara poliester dan jerami padi adalah 30:70%; 35:65%; 40:60%; 45:55%; dan 50:50%, yang dilanjutkan dengan pengempaan. Karakterisasi dan analisa yang dilakukan menunjukkan bahwa sifat mekanik tegangan optimum pada campuran 50:50 antara polyester dan jerami p...

  19. KONSEP WANUA DAN PALILI DI KONFEDERASI AJATAPPARENG: SEJARAH DAN BUDAYA POLITIK ORANG BUGIS DI SULAWESI SELATAN

    OpenAIRE

    Abd. Latif

    2014-01-01

    Kajian ini akan mendiskusikan tentang konsep wanua dan palili dalam struktur kerajaan-kerajaan yang tergabung dalam Konfederasi Ajatappareng di Sulawesi Selatan. Wanua dan palili adalah dua istilah yang digunakan oleh kerajaan pusat terhadap daerah bawahannya. Pertanyaannya, mengapa ada daerah bawahan yang disebut wanua dan yang lainnya disebut palili. Apakah kriteria yang mesti dipunyai satu daerah untuk disebut sebagai wanua dan apakah pula kriteria yang mesti dipunyai satu daerah untuk dis...

  20. Analisis Kesesuaian dan Daya Dukung untuk Wisata Pantai dan Snorkeling di Pulau Hoga, Kabupaten Wakatobi.

    OpenAIRE

    Ahmad, Bahar

    2014-01-01

    Kawasan wisata bahari agar dapat dimanfaatkan secara berkelanjutan maka pemanfaatan yang dilakukan harus berkesesuaian dengan kondisi dan daya dukung kawasan. Penelitian ini bertujuan untuk menganalisis kesesuaian dan daya dukung untuk wisata pantai dan snorkeling di Pulau Hoga Kabupaten Wakatobi. Data yang digunakan dalam penelitian ini menggunakan data primer dan sekunder. Pengumpulan data primer menggunakan metode survei lapangan, sedangkan data sekunder diperoleh dari Badan Pusat Statis...

  1. KORUPSI DAN PELANGGARAN HAK EKONOMI, SOSIAL DAN BUDAYA DI INDONESIA

    Directory of Open Access Journals (Sweden)

    Robby Darwis Nasution

    2016-02-01

    Full Text Available Korupsi merupakan budaya yang sudah lumrah terjadi di Indonesia, dalam keseharian perpolitikan di Indonesia bahkan tidak akan lepas dari aktifitas korupsi dimana pada kenyataannya korupsi sendiri akan berdampak sistemik bukan hanya berdapmapa kepada kemakmuran Negara tetapi juga berdampak kepada kesejahteraan masyarakat Indonesia. Kesejahteraan Masyarakat sesungguhnya dapat dilihat dari tingkat pemenuhan hak EKOSOB (Ekonomi, Sosial dan Budaya, ketiga poin tersebut merupakan bagian kecil indikator kesejahteraan rakyat. Bersama-sama dengan Hak Sipil, hak ekosob telah diakui secara internasional sebagai bagian dari the international bill of human rights. Kerangka hukumnya menjadi semakin jelas setelah hak-hak tersebut dituangkan dalam perjanjian multilateral yang tertuang dalam Covenan on Economic, Social and Cultural Rights (selanjutnya disingkat CESCR, yang disahkan oleh Majelis Umum PBB pada tahun 1966 sebagai pelaksanaan dari prinsip-prinsip yang dimuat dalam DUHAM 1948. Kewenangan negara yang dalam hal ini adalah pemerintah untuk menjamin hak-hak ekonomi, sosial dan budaya di indonesia dirasa tidak memenuhi hasil yang memadai sehingga dapat dilihat dengan masih banyaknya pengangguran, kemiskinan, dan rendahnya tingkat pendidikan warga negara. Selain itu, tingkat korupsi di Indonesia masih sangat tinggi dibanding negara-negara lain yang menyebabkan tingkat pelanggaran hak EKOSOB di Indonesia masih sangat tinggi.

  2. Analyse des ecarts de previsions de benefices dans les notes d’information des introductions en bourse: Cas de la bourse de Casablanca

    Directory of Open Access Journals (Sweden)

    Ilyas E.L. Ghordaf

    2013-12-01

    Full Text Available Cet article étudie les déterminants des écarts de prévisions de bénéfices des entreprises introduites en bourse et vérifie si la performance boursière à long terme des actions est fonction de ces écarts. Les tests sont réalisés sur un échantillon de 26 admissions à la cote de la bourse marocaine entre 2000 et 2010. Les résultats empiriques montrent que l’erreur moyenne de prévision dépend de l’endettement et de l’âge de l’entreprise. Par ailleurs, l’étude indique que les firmes qui publient des résultats optimistes de bénéfice dans les notes d’information d’introduction en bourse dégagent des rentabilités anormales cumulées plus faibles que celles obtenues par les sociétés pessimistes.

  3. KEBEBASAN BERAGAMA DAN NORMA-NORMANYA

    Directory of Open Access Journals (Sweden)

    Abdillah Halim

    2013-04-01

      Abstrak Perdebatan tidak berkesudahan terus mewarnai perbincangan dan praktek kebebasan beragama, terutama mengenai kata “kebebasan” yang dilekatkan pada agama dan kepercayaan. Jika “kebebasan” dimaknai sebagai kemerdekaan, apa lantas berarti tidak adanya batasan terhadap kemerdekaan tersebut, dalam arti bahwa kebebasan tersebut bersifat mutlak. Atau barangkali “kebebasan” di sini dimaknai sebagai kebebasan relatif yang membuka kemungkinan perumusan definisi dan ruang lingkup yang jelas. Penulis berpandangan bahwa kebebasan beragama bukan kebebasan mutlak yang tidak menuntut pendefinisian, perumusan ruang-lingkup serta norma norma, dan pengaturan. Kebebasan mutlak pada taraf yang demikian bukan kebebasan yang bermakna sebenarnya, namun dapat berarti sebuah keadaan anarki dan anomi. Kebebasan beragama adalah kebebasan relatif yang menuntut adanya penjelasan tentang definisi, ruang lingkup, norma-norma, dan batasan-batasannya.

  4. Persebaran Layanan dan Infrastruktur Telekomunikasi Provinsi Papua

    Directory of Open Access Journals (Sweden)

    Prajna Deshanta Ibnugraha

    2014-05-01

    Full Text Available Layanan dan infrastruktur telekomunikasi merupakan bagian penting dari kehidupan modern karena hampir di segala bidang membutuhkan hal tersebut seperti pendidikan, pemerintahan, ekonomi dan sebagainya. Oleh karena pentingnya sektor telekomunikasi di Indonesia sebagai negara kepulauan maka perlu evaluasi tentang penyebaran layanan dan infrastrukturnya selain dilihat dari sisi fungsional dan perkembangan teknologinya. Provinsi Papua adalah provinsi terbesar di Indonesia namun justru memiliki layanan telekomunikasi yang paling sedikit dan terbatas. Demikian pula untuk penyebaran layanan ke kabupaten maupun ke distrik (kecamatan masih belum merata. Hal tersebut terbukti dari laporan hasil distribusi pita frekuensi yang hanya 1,5% untuk kawasan Maluku dan Papua serta kerapatan layanan tiap kabupaten yang ditunjukkan pada hasil penelitian ini.

  5. Method for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder

    Indian Academy of Sciences (India)

    Sulardjaka; Jamasri; M W Wildan; Kusnanto

    2011-07-01

    A novel process for increasing -SiC yield on solid state reaction of coal fly ash and micro powder activated carbon powder has been proposed. -SiC powder was synthesized at temperature 1300°C for 2 h under vacuum condition with 1 l/min argon flow. Cycling synthesis process has been developed for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder. Synthesized products were analyzed by XRD with Cu-K radiation, FTIR spectrometer and SEM fitted with EDAX. The results show that the amount of relative -SiC is increased with the number of cycling synthesis.

  6. Uniformity's influence of silica xerogel on synthesis efficiency of SiC nanorods by carbothermal reduction

    Energy Technology Data Exchange (ETDEWEB)

    Huynh Thi Ha; Nguyen Thi Thu Ha; Phan Viet Phong; Dao Tran Cao; Le Quang Huy; Nguyen The Quynh [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Cao Tuan Anh [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan Street, Badinh Distr., Hanoi (Viet Nam)], E-mail: haht@ims.vast.ac.vn

    2009-09-01

    Silica xerogels containing nanocarbon were milled for several hours before the carbothermal reduction processing. The formation of SiC nanorods was investigated at different annealing temperatures. It is shown that the formation temperature of SiC nanorods can be decreased if the powder size of milled silica xerogels is lower than 100 nm. The morphology, structure and production efficiency of synthesized SiC were determined by scanning electron microscopy SEM, X-ray diffraction XRD and thermo-gravimetric analysis TGA measurements. It is evident that production efficiency of synthesized SiC nanorods clearly depends on uniformity of precursor materials.

  7. Experimental Investigation of Mechanical and Thermal properties of sisal fibre reinforced composite and effect of sic filler material

    Science.gov (United States)

    Surya Teja, Malla; Ramana, M. V.; Sriramulu, D.; Rao, C. J.

    2016-09-01

    With a view of exploring the potential use of natural recourses, we made an attempt to fabricate sisal fibre polymer composites by hand lay-up method. Natural fiber composites are renewable, cheap and biodegradable. Their easy availability, lower density, higher specific properties, lower cost, satisfactory mechanical and thermal properties, non-corrosive nature, makes them an attractive ecological alternative to glass, carbon or other man-made synthetic fibers. In this work, the effect of SiC on mechanical and thermal properties of natural sisal fiber composites are investigated. The composite has been made with and without SiC incorporating natural sisal fiber with polyester as bonding material. The experimental outcomes exhibited that the tensile strength of composite with 10%SiC 2.53 times greater than that of composite without SiC. The impact strength of composite with 10% SiC is 1.73 times greater than that of composite without SiC plain polyester. Thermal properties studied include thermal conductivity, specific heat capacity, thermal diffusivity, thermal degradation and stability. Three different samples with 0%, 5%, 10% SiC powder are considered. With the addition of SiC filler powder, thermal conductivity increases, specific heat capacity gradually increases then decreases, thermal diffusivity increases and thermal stability improves with Sic powder.

  8. The streptococcal inhibitor of complement (SIC) protects Streptococcus pyogenes from bacteriocin-like inhibitory substance (BLIS) from Streptococcus salivarius.

    Science.gov (United States)

    Minami, Masaaki; Ohmori, Daisuke; Tatsuno, Ichiro; Isaka, Masanori; Kawamura, Yoshiaki; Ohta, Michio; Hasegawa, Tadao

    2009-09-01

    Streptococcus salivarius inhibits the growth of Streptococcus pyogenes in vitro. Streptococcus pyogenes has various virulence factors, including the streptococcus inhibitor of complement (SIC). Although SIC inhibits the activity of the peptides LL-37 and NAP1, the relationship between SIC and the bacteriocin-like inhibitory substance (BLIS) has not been elucidated. Here, we evaluated whether S. salivarius BLIS affects S. pyogenes SIC. We created three deltasic mutant strains from three S. pyogenes strains and performed deferred antagonism assays. The test strains were BLIS-positive S. salivarius JCM5707 and BLIS-negative S. salivarius NCU12. Deferred antagonism assays with JCM5707 showed that the inhibitory zones in the three deltasic mutant strains were wider than those in the three wild-type strains. Streptococcus pyogenes was cultured in BLIS-containing broth and the change in SIC in the supernatant was assessed by two-dimensional gel electrophoresis (2-DE). The 2-DE analysis of S. pyogenes exoproteins with the JCM5707 supernatant showed reduced SIC compared with those without the JCM5707 supernatant. Changes in sic mRNA levels affected by S. salivarius BLIS were evaluated by a reverse transcriptase-PCR. The sic mRNA level was affected more by the BLIS-positive S. salivarius than by the BLIS-negative strain. Our result indicates that SIC plays a role in the inhibition of S. salivarius BLIS.

  9. Wear Behaviour of Al-6061/SiC Metal Matrix Composites

    Science.gov (United States)

    Mishra, Ashok Kumar; Srivastava, Rajesh Kumar

    2016-06-01

    Aluminium Al-6061 base composites, reinforced with SiC particles having mesh size of 150 and 600, which is fabricated by stir casting method and their wear resistance and coefficient of friction has been investigated in the present study as a function of applied load and weight fraction of SiC varying from 5, 10, 15, 20, 25, 30, 35 and 40 %. The dry sliding wear properties of composites were investigated by using Pin-on-disk testing machine at sliding velocity of 2 m/s and sliding distance of 2000 m over a various loads of 10, 20 and 30 N. The result shows that the reinforcement of the metal matrix with SiC particulates up to weight percentage of 35 % reduces the wear rate. The result also show that the wear of the test specimens increases with the increasing load and sliding distance. The coefficient of friction slightly decreases with increasing weight percentage of reinforcements. The wear surfaces are examined by optical microscopy which shows that the large grooved regions and cavities with ceramic particles are found on the worn surface of the composite alloy. This indicates an abrasive wear mechanism, which is essentially a result of hard ceramic particles exposed on the worn surfaces. Further, it was found from the experimentation that the wear rate decreases linearly with increasing weight fraction of SiC and average coefficient of friction decreases linearly with increasing applied load, weight fraction of SiC and mesh size of SiC. The best result has been obtained at 35 % weight fraction and 600 mesh size of SiC.

  10. Diffusion of Ag, Au and Cs implants in MAX phase Ti3SiC2

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin; Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R.; Zhang, Chonghong; Gou, Jie

    2015-05-16

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti3SiC2/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including x-ray diffraction, electron backscatter diffraction, energy dispersive x-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti3SiC2 within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti3SiC2 was also observed. Cs out-diffusion and release from Ti3SiC2 occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  11. A study on the high densification process of CVI SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Doo Jin; Son, Ji Hye; Jun, Jin O. [Yonsei University, Seoul (Korea)

    2002-03-01

    A novel process called in-situ whisker growing and matrix filling was designed to overcome the problem of conventional ICVI process which make composites porous. Fiber reinforced SiC matrix composites were successfully fabricated by the process in the present study. Methyltrichlorosilane(CH{sub 3}SiCl{sub 3},MTS) was chosen as a source precursor of SiC. Hydrogen was used as a dilute gas for the in-situ whisker growing process and nitrogen was used as a dilute gas for the SiC matrix filling process. In order to increase the fracture toughness of the composites, the fibers were coated with a thin pyrolytic carbon layer at 1000 .deg. C before ICVI process. In case of the monolithic SiC-SiC composites, SiC whisker was grown at the temperature of 1100 .deg. C with the input gas ratio of 15. SiC-SiC composites obtained by the suggested process were denser than the composites obtained by conventional ICVI process. Also, in case of the stacked SiC-SiC composites, SiC whisker was grown at the temperature of 1100 .deg. C with the input gas ratio of 20 and 30. In addition, the SiC whisker was also grown at 1150 .deg.C with the input gas ratio of 20. The optimum condition of the in-situ whisker growing for the following matrix filling process is 1100 .deg. C, {alpha}=20, and 2hr. The designed process, in-situ whisker growing and matrix filling, was confirmed as a novel process which can fabricate high density fiber reinforced SiC matrix composites. 40 refs., 24 figs., 7 tabs. (Author)

  12. Effect of SiC particles on microarc oxidation process of magnesium matrix composites

    Science.gov (United States)

    Wang, Y. Q.; Wang, X. J.; Gong, W. X.; Wu, K.; Wang, F. H.

    2013-10-01

    SiC particles are an important reinforced phase in metal matrix composites. Their effect on the microarc oxidation (MAO, also named plasma electrolytic oxidation-PEO) process of SiCp/AZ91 Mg matrix composites (MMCs) was studied and the mechanism was revealed. The corrosion resistance of MAO coating was also investigated. Voltage-time curves during MAO were recorded to study the barrier film status on the composites. Scanning electron microscopy was used to characterize the existing state of SiC particles in MAO. Energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy were used to analyze the chemical composition of the coating. Corrosion resistance of the bare and coated composites was evaluated by potentiodynamic polarization curves in 3.5% NaCl solution. Results showed that the integrality and electrical insulation properties of the barrier film on the composites were destroyed by the SiC particles. Consequently, the sparking discharge at the early stage of MAO was inhibited, and the growth efficiency of the MAO coating decreased with the increase in the volume fraction of SiC particles. SiC particles did not exist stably during MAO; they were oxidized or partially oxidized into SiO2 before the overall sparking discharge. The transformation from semi-conductive SiC to insulating SiO2 by oxidation restrained the current leakage at the original SiC positions and then promoted sparking discharge and coating growth. The corrosion current density of SiCp/AZ91 MMCs was reduced by two orders of magnitude after MAO treatment. However, the corrosion resistances of the coated composites were lower than that of the coated alloy.

  13. Effect of SiC particles on microarc oxidation process of magnesium matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.Q., E-mail: qiuorwang@hrbeu.edu.cn [Corrosion and Protection Laboratory, Education Ministry Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Harbin 150001 (China); Wang, X.J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Gong, W.X. [Corrosion and Protection Laboratory, Education Ministry Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Harbin 150001 (China); Wu, K. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, F.H. [Corrosion and Protection Laboratory, Education Ministry Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Harbin 150001 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2013-10-15

    SiC particles are an important reinforced phase in metal matrix composites. Their effect on the microarc oxidation (MAO, also named plasma electrolytic oxidation-PEO) process of SiC{sub p}/AZ91 Mg matrix composites (MMCs) was studied and the mechanism was revealed. The corrosion resistance of MAO coating was also investigated. Voltage–time curves during MAO were recorded to study the barrier film status on the composites. Scanning electron microscopy was used to characterize the existing state of SiC particles in MAO. Energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy were used to analyze the chemical composition of the coating. Corrosion resistance of the bare and coated composites was evaluated by potentiodynamic polarization curves in 3.5% NaCl solution. Results showed that the integrality and electrical insulation properties of the barrier film on the composites were destroyed by the SiC particles. Consequently, the sparking discharge at the early stage of MAO was inhibited, and the growth efficiency of the MAO coating decreased with the increase in the volume fraction of SiC particles. SiC particles did not exist stably during MAO; they were oxidized or partially oxidized into SiO{sub 2} before the overall sparking discharge. The transformation from semi-conductive SiC to insulating SiO{sub 2} by oxidation restrained the current leakage at the original SiC positions and then promoted sparking discharge and coating growth. The corrosion current density of SiC{sub p}/AZ91 MMCs was reduced by two orders of magnitude after MAO treatment. However, the corrosion resistances of the coated composites were lower than that of the coated alloy.

  14. SiC JFET Transistor Circuit Model for Extreme Temperature Range

    Science.gov (United States)

    Neudeck, Philip G.

    2008-01-01

    A technique for simulating extreme-temperature operation of integrated circuits that incorporate silicon carbide (SiC) junction field-effect transistors (JFETs) has been developed. The technique involves modification of NGSPICE, which is an open-source version of the popular Simulation Program with Integrated Circuit Emphasis (SPICE) general-purpose analog-integrated-circuit-simulating software. NGSPICE in its unmodified form is used for simulating and designing circuits made from silicon-based transistors that operate at or near room temperature. Two rapid modifications of NGSPICE source code enable SiC JFETs to be simulated to 500 C using the well-known Level 1 model for silicon metal oxide semiconductor field-effect transistors (MOSFETs). First, the default value of the MOSFET surface potential must be changed. In the unmodified source code, this parameter has a value of 0.6, which corresponds to slightly more than half the bandgap of silicon. In NGSPICE modified to simulate SiC JFETs, this parameter is changed to a value of 1.6, corresponding to slightly more than half the bandgap of SiC. The second modification consists of changing the temperature dependence of MOSFET transconductance and saturation parameters. The unmodified NGSPICE source code implements a T(sup -1.5) temperature dependence for these parameters. In order to mimic the temperature behavior of experimental SiC JFETs, a T(sup -1.3) temperature dependence must be implemented in the NGSPICE source code. Following these two simple modifications, the Level 1 MOSFET model of the NGSPICE circuit simulation program reasonably approximates the measured high-temperature behavior of experimental SiC JFETs properly operated with zero or reverse bias applied to the gate terminal. Modification of additional silicon parameters in the NGSPICE source code was not necessary to model experimental SiC JFET current-voltage performance across the entire temperature range from 25 to 500 C.

  15. MANAJEMEN BIMBINGAN DAN KONSELING BERBASIS PERMENDIKBUD NOMOR 111 TAHUN 2014

    Directory of Open Access Journals (Sweden)

    Edris Zamroni

    2015-11-01

    Full Text Available Manajemen bimbingan dan konseling adalah segala upaya atau cara yang digunakan  untuk mendayagunakan secara optimal semua komponen atau sumber daya (tenaga, dana, sarana-prasarana dan sistem informasi berupa himpunan data bimbingan dan konseling untuk menyelenggarakan pelayanan bimbingan dan konseling dalam rangka mencapai tujuan yang telah ditentukan. Permendikbud Nomor 111 Tahun 2014 diterbitkan untuk menjadi acuan baru pelaksanaan tata kelola bimbingan dan konseling mulai dari planning, organizing, staffing, leading dan controlling.

  16. Oxidation of SiC Fiber-Reinforced SiC Matrix Composites with a BN Interphase

    Science.gov (United States)

    Opila, Elizabeth; Boyd, Meredith K.

    2010-01-01

    SiC-fiber reinforced SiC matrix composites with a BN interphase were oxidized in reduced oxygen partial pressures of oxygen to simulate the environment for hypersonic vehicle leading edge applications. The constituent fibers as well as composite coupons were oxidized in oxygen partial pressures ranging from 1000 ppm O2 to 5% O2 balance argon. Exposure temperatures ranged from 816 C to 1353 C (1500 F to 2450 F). The oxidation kinetics of the coated fibers were monitored by thermogravimetric analysis (TGA). An initial rapid transient weight gain was observed followed by parabolic kinetics. Possible mechanisms for the transient oxidation are discussed. One edge of the composite coupon seal coat was ground off to simulate damage to the composite which allowed oxygen ingress to the interior of the composite. Oxidation kinetics of the coupons were characterized by scanning electron microscopy since the weight changes were minimal. It was found that sealing of the coupon edge by silica formation occurred. Differences in the amount and morphology of the sealing silica as a function of time, temperature and oxygen partial pressure are discussed. Implications for use of these materials for hypersonic vehicle leading edge materials are summarized.

  17. Imunopatogenesis Treponema pallidum dan Pemeriksaan Serologi

    OpenAIRE

    Efrida ,; Elvinawaty .

    2014-01-01

    AbstrakSifilis adalah penyakit menular seksual yang sangat infeksius, disebabkan oleh bakteri berbentuk spiral, Treponema pallidum subspesies pallidum. Penyebaran sifilis di dunia telah menjadi masalah kesehatan yang besar dengan jumlah kasus 12 juta pertahun. Infeksi sifilis dibagi menjadi sifilis stadium dini dan lanjut. Sifilis stadium dini terbagi menjadi sifilis primer, sekunder, dan laten dini. Sifilis stadium lanjut termasuk sifilis tersier (gumatous, sifilis kardiovaskular dan neurosi...

  18. Manifestasi Kehamilan Di Rongga Mulut Dan Perawatannya

    OpenAIRE

    Fatimah

    2008-01-01

    Kehamilan merupakan sebuah proses fisiologis yang melibatkan banyak sistem dalam tubuh dan mengakibatkan terjadinya perubahan pada sistem baik secara anatomis maupun fisiologis seperti pada sistem reproduksi, endokrin, sirkulasi pencernaan dan juga rongga mulut. Manifestasi kehamilan di rongga mulut merupakan suatu kondisi yang sering tetjadi, baik pada gigi maupun pada jaringan di sekitamya. Hal ini dapat terlihat dan tingginya tingkat karies, erosi enamel, terjadinya gingivitis kehamila...

  19. Perkembangan Pendidikan Meunasah dan Dayah di Aceh

    OpenAIRE

    Mujianto Solichin

    2015-01-01

    Meunasah dan Dayah dalam masa perjalanannya tumbuh seiring perkembangan kerajaan-kerajaan Islam di Aceh yang memiliki peran strategis dalam pembentukan kebudayaan Islam di wilayah kekuasaan mereka masing-masing. Ini membuktikan bahwa kerajaan-kerajaan Melayu baik di Malaka (Malaysia) maupun di Aceh (Nangroe Aceh Darussalam) memiliki jaringan arkeologi sejarah kebudayaan dan peradaban yang terbentuk berdasarkan motivasi agama dan menjadikan tradisi Melayu sebagai identitas pemersatu mereka. Ke...

  20. KEBEBASAN BERAGAMA DAN NORMA-NORMANYA

    OpenAIRE

    Abdillah Halim

    2013-01-01

    KEBEBASAN BERAGAMA DAN NORMA-NORMANYA Abdillah Halim Jurusan Syariah, Sekolah Tinggi Agama Islam (STAI) Ngawi   Abstrak Perdebatan tidak berkesudahan terus mewarnai perbincangan dan praktek kebebasan beragama, terutama mengenai kata “kebebasan” yang dilekatkan pada agama dan kepercayaan. Jika “kebebasan” dimaknai sebagai kemerdekaan, apa lantas berarti tidak adanya batasan terhadap kemerdekaan tersebut, dalam arti bahwa kebebasan tersebut bersifat mutlak. Atau barangkali “ke...

  1. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Martin, Daniel [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Dr. Matt [University of Arkansas; Lamichhane, Ranjan [University of Arkansas; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas

    2014-01-01

    This paper presents the testing results of an all-silicon carbide (SiC) intelligent power module (IPM) for use in future high-density power electronics applications. The IPM has high-temperature capability and contains both SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter to showcase the performance of the module in a system level application. The converter was initially operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The efficiency of the converter was then evaluated experimentally and optimized by increasing the overdrive voltage on the SiC gate driver ICs. Overall a peak efficiency of 97.7% was measured at 3.0 kW output. The converter s switching frequency was then increased to 500 kHz to prove the high frequency capability of the power module was then pushed to its limits and operated at a switching frequency of 500 kHz. With no further optimization of components, the converter was able to operate under these conditions and showed a peak efficiency of 95.0% at an output power of 2.1 kW.

  2. Bahasa Roh: Apa dan Bagaimana?

    Directory of Open Access Journals (Sweden)

    Hermanto Suanglangi

    2005-04-01

    Full Text Available Apakah itu glossalalia? Glossalalia adalah adalah kata 1.ang dibangun daridtra kata Cerika, yaitu " glossa" yang berarti bahasa atau lidah dan "lalia"artinva pembicaraan, perkataan. Sehingga "glossalalia" adalah suatu pembicaraan dengan lidah, atau perkataan denganlidah. Dari istilah inilah maka orang biasa menyebutnya dengan bahasa roh dan bahasa lidah, di mana bahasa roh, atau bahasa lidah adalah semacam bahasa yang dengan kemampuan Roh Kudus orang dapat mengucapkannya. Baik dalam Korintus maupun dalam Kisah Para Rasul, sama-sama disebutbahasa roh karena keduanya semacam bahasa yang diucapkan dengan kemampuan dari Roh yang sama yaitu Roh Kudus.

  3. KOMPLIKASI, PENCEGAHAN DAN PENANGANAN EKSTRAVASASI AGEN KEMOTERAPI

    Directory of Open Access Journals (Sweden)

    I G A Mirah K

    2012-12-01

    Full Text Available Ekstravasasi agen kemoterapi ke jaringan sekitarnya merupakan kecelakaan yangdapat menyebabkan kerusakan jaringan progresif ireversibel dalam hitungan jamsampai hari. Manifestasi klinis ekstravasasi berupa nyeri, edema, eritema, danindurasi yang kemudian berkembang menjadi ulkus dan eschar hitam dankerusakan jaringan yang mendasarinya. Pencegahan terjadinya ekstravasasi dapatdilakukan dengan menggunakan pembuluh darah yang paten dan dengan aliranyang cepat dan tetap memperhatikan keluhan yang disampaikan pasien. Setiaptenaga kesehatan yang akan menangani pasien kanker dengan kemoterapi, dituntutmemiliki pengetahuan mengenai ekstravasasi agen kemoterapi yang bergunadalam meningkatkan pelayanan pada pasien dan mengurangi morbiditas.

  4. Sistem Pengukur Suhu dan Kelembaban Ruang Server

    Directory of Open Access Journals (Sweden)

    Muhammad Fahmi Awaj

    2014-01-01

    Full Text Available Makalah ini membahas tentang perancangan sistem pengukur suhu dan kelembaban ruang server yang dapat meningkatkan efisiensi daya listrik dengan menggunakan arduino. Sistem terdiri dari sensor DHT 11 yang berfungsi untuk mengambil data berupa suhu dan kelembaban ruang server kemudian ditampilkan dalam LCD 16x2. Data suhu dan kelembaban ditampilkan juga ke dalam website dengan menggunakan IP address tertentu yang sebelumnya board arduino telah terhubung dengan ethernet shield. Suhu yang melebihi 270C akan menyalakan relay dan kipas serta sistem akan mengirim peringatan sms secara otomatis kepada administrator ruang server melalui sistem sms secara periodik hanya setiap tiga detik. Sistem peringatan sms akan berhenti jika suhu kurang 270C.

  5. KECEMASAN DAN STRATEGI COPING WARIA PELACUR

    Directory of Open Access Journals (Sweden)

    Haris Herdiansyah

    2007-05-01

    Full Text Available Dunia pelacuran adalah penuh dengan tekanan, ancaman dan hal negatif cacat yang menyebabkan ketertarikan kepada pelacur oleh karena itu mendorong pelacur untuk menciptakan strategi menghadapi cukup untuk menghadapi apa yang rasa mereka . Tujuan dari studi ini akan meliputi ke luar ketertarikan dan strategi pelacur yang menghadapi transgender di tiga lingkungan sosial berbeda termasuk dalam keluarga, masyarakat dan “ cebongan” ( tempat di mana pelacur bekerja. Ini adalah suatu riset kualitatif. Karena alat pengumpulan data adalah wawancara, dan pengamatan. Studi ini menggunakan purposive sampling. Ada 3 subjek dan 4 orang informan. Untuk menganalisis data menggunakan model interaktif dari Miles & Huberman yang terdiri dari 3 langkah, yaitu reduksi data, menampilkan data dan kesimpulan serta verifikasi. Hasil dari penelitian ini, banyak kecemasan yang dialami oleh waria pelacur yang datang dari lingkungan yang berbeda-beda. Dari keluarga misalnya, merupakan sumber kecemasan tertinggi, ketika keluarga waria mengetahui profesi mereka. Sumber lain berasal dari pengucilan oleh masyarakat dan mucikari, penangkapan oleh polisi dan preman, persaingan antar pelacur dan kekerasan dari pengguna mereka di “cebongan”

  6. KONTEKTUALISASI DAN (KEMUNGKINAN KONSEKUENSINYA BAGI PSIKOLOGI

    Directory of Open Access Journals (Sweden)

    Prof. Supratiknya

    2015-09-01

    jaran di perguruan tinggi seperti kita kenal sekarang (selanjutnya disebut psikologi, lahir di Jerman pada penghujung abad ke‐19. Selanjutnya psikologi berkembang pesat di Amerika Utara khususnya Amerika Serikat dan negara‐negara lain di Eropa yang lebih dulu mengalami industrialisasi khususnya di Eropa Barat. 1 Alhasil, paling tidak sampai dasawarsa 1980‐an perkembangan dan persebaran psikologi di tingkat global ditandai oleh ketimpangan di antara apa yang oleh Moghaddam (1987 disebut tiga dunia tempat psikologi dikembangkan dan dipraktekkan, disimak antara lain berdasarkan besarnya produksi pengetahuan psikologis yang disebarluaskan melalui penyelenggaraan pendidikan tinggi psikologi maupun lewat publikasi ilmiah berupa baik berkala maupun buku rujukan dan buku teks.

  7. TASAWUF DAN TANTANGAN PERUBAHAN SOSIAL

    Directory of Open Access Journals (Sweden)

    Yusno Abdullah Otta

    2010-12-01

    Full Text Available Abstract: Sufism in the eras of globalization and information often faces considerable challenges. The function and role of religion in modern life have in some aspects diminished, including sufism because it is claimed to have played no or less role in resolving problems nor stimulating social change. As one of Islamic traditions, sufism makes ihsan as its essential teaching. By this concept, sufism encourages humans to pray to God wholeheartedly. Sufism is now required to show its own existence and function by making fundamental contribution for modern life, an era which differ socio-culturally from the one when sufism firstly emerged. Sufism thus needs to adapt itself to the changes in the era of information and globalization so that it will remain relevant and suitable for human progress. Sufism needs to release itself from its exclusivism and to avoid being trapped in its own logic, namely speculative-trancendentalism Abstrak: Tasawuf di era globalisasi dan informasi seperti saat ini tengah menghadapi tantangan yang sangat berat. Kehidupan modern sudah sampai pada taraf tidak lagi mempercayai fungsi dan peran agama, termasuk di dalamnya tasawuf, sebagai ‘sesuatu’ yang dapat memberikan solusi bagi perubahan sosial. Sebagai manifestasi paripurna dari ajaran Islam, tasawuf berintikan pada konsep Ihsān yang mengajarkan untuk beribadah kepada Sang Pencipta secara ikhlas. Untuk menunjukkan eksistensinya, tasawuf dituntut peran aktifnya secara konstruktif-solutif terhadap berbagai kebutuhan manusia modern yang amat berbeda dengan setting maupun struktur masyarakat pada saat tasawuf “dilahirkan” pada zamannya. Tasawuf dituntut untuk memerlukan “baju” baru di era informasi yang kerap berubah ini, agar tetap realible dan suitable dengan kemajuan zaman. Hal itu dapat dilakukan dengan berusaha “keluar” dari eksklusifismenya dengan meminjam tradisi filsafat analitik pasca positivisme dan tradisi eksistensialis serta dinamika filsafat

  8. Analisis Kinerja EIGRP dan OSPF pada Topologi Ring dan Mesh

    Directory of Open Access Journals (Sweden)

    DWI ARYANTA

    2016-02-01

    Full Text Available ABSTRAK EIGRP (Enhanced Interior Gateway Routing Protocol dan OSPF (Open Shortest Path Fisrt adalah routing protokol yang banyak digunakan pada suatu jaringan komputer. EIGRP hanya dapat digunakan pada perangkat Merk CISCO, sedangkan OSPF dapat digunakan pada semua merk jaringan. Pada penelitian ini dibandingkan delay dan rute dari kedua routing protokol yang diimplementasikan pada topologi Ring dan Mesh. Cisco Packet Tracer 5.3 digunakan untuk mensimulasikan kedua routing protokol ini. Skenario pertama adalah perancangan jaringan kemudian dilakukan pengujian waktu delay 100 kali dalam 5 kasus. Skenario kedua dilakukan pengujian trace route untuk mengetahui jalur yang dilewati paket data lalu memutus link utama. Pada skenario kedua juga dilakukan perbandingan nilai metric dan cost hasil simulasi dengan perhitungan rumus. Skenario ketiga dilakukan pengujian waktu konvergensi untuk setiap routing protokol pada setiap topologi. Hasilnya EIGRP lebih cepat 386 µs daripada OSPF untuk topologi Ring sedangkan OSPF lebih cepat 453 µs daripada EIGRP untuk topologi Mesh. Hasil trace route menunjukan rute yang dipilih oleh routing protokol yaitu nilai metric dan cost yang terkecil. Waktu konvergensi rata-rata topologi Ring pada EIGRP sebesar 12,75 detik dan 34,5 detik pada OSPF sedangkan topologi Mesh di EIGRP sebesar 13 detik dan 35,25 detik di OSPF. Kata Kunci : EIGRP, OSPF, Packet Tracer 5.3, Ring, Mesh, Konvergensi ABSTRACT EIGRP (Enhanced Interior Gateway Routing Protocol and OSPF (Open Shortest Path Fisrt is the routing protocol that is widely used in a computer network. EIGRP can only be used on devices Brand CISCO, while OSPF can be used on all brands of network. In this study comparison of both the delay and the routing protocol implemented on Ring and Mesh topology. Cisco Packet Tracer 5.3 is used to simulate both the routing protocol. The first scenario is the design of the network and then do the test of time delay 100 times in 5 cases. The

  9. Analisis Perbandingan Database Jurnal Elektronik Emerald, ProQuest ABI/INFORM dan SpringerLink Bidang Manajemen dan Ekonomi

    OpenAIRE

    Karyatin, Arianiansyah

    2016-01-01

    Penelitian ini dilakukan pada situs database jurnal elektronik Emerald, ProQuest ABI/INFORM dan SpringerLink. Tujuan penelitian ini adalah untuk mengetahui bagaimana konten (muatan) subjek kajian manajemen dan ekonomi pada database Emerald, ProQuest ABI/INFORM dan SpringerLink dan untuk mengetahui di dalam database manakah diantara database Emerald, ProQuest ABI/INFORM, dan Springerlink yang memuat bidang kajian manajemen dan ekonomi yang paling lengkap. Metode yang digunakan dalam pene...

  10. Analisis Perbandingan Database Jurnal Elektronik Emerald, ProQuest ABI/INFORM dan SpringerLink Bidang Manajemen dan Ekonomi

    OpenAIRE

    Karyatin, Arianiansyah

    2016-01-01

    Penelitian ini dilakukan pada situs database jurnal elektronik Emerald, ProQuest ABI/INFORM dan SpringerLink. Tujuan penelitian ini adalah untuk mengetahui bagaimana konten (muatan) subjek kajian manajemen dan ekonomi pada database Emerald, ProQuest ABI/INFORM dan SpringerLink dan untuk mengetahui di dalam database manakah diantara database Emerald, ProQuest ABI/INFORM, dan Springerlink yang memuat bidang kajian manajemen dan ekonomi yang paling lengkap. Metode yang digunakan dalam pene...

  11. Thermal conductivity analysis of SiC ceramics and fully ceramic microencapsulated fuel composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeon-Geun, E-mail: hglee@kaeri.re.kr [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon (Korea, Republic of); Kim, Daejong [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon (Korea, Republic of); Lee, Seung Jae [KEPCO Nuclear Fuel, 242, Daedeok-daero, Yuseong-gu, Daejeon (Korea, Republic of); Park, Ji Yeon; Kim, Weon-Ju [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon (Korea, Republic of)

    2017-01-15

    Highlights: • Thermal conductivity of SiC ceramics and FCM pellets was measured and discussed. • Thermal conductivity of FCM pellets was analyzed by the Maxwell-Eucken equation. • Effective thermal conductivity of TRISO particles applied in this study was assumed. - Abstract: The thermal conductivity of SiC ceramics and FCM fuel composites, consisting of a SiC matrix and TRISO coated particles, was measured and analyzed. SiC ceramics and FCM pellets were fabricated by hot press sintering with Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} sintering additives. Several factors that influence thermal conductivity, specifically the content of sintering additives for SiC ceramics and the volume fraction of TRISO particles and the matrix thermal conductivity of FCM pellets, were investigated. The thermal conductivity values of samples were analyzed on the basis of their microstructure and the arrangement of TRISO particles. The thermal conductivity of the FCM pellets was compared to that predicted by the Maxwell-Eucken equation and the thermal conductivity of TRISO coated particles was calculated. The thermal conductivity of FCM pellets in various sintering conditions was in close agreement to that predicted by the Maxwell-Eucken equation with the fitted thermal conductivity value of TRISO particles.

  12. Surface characteristics and corrosion behaviour of WE43 magnesium alloy coated by SiC film

    Science.gov (United States)

    Li, M.; Cheng, Y.; Zheng, Y. F.; Zhang, X.; Xi, T. F.; Wei, S. C.

    2012-01-01

    Amorphous SiC film has been successfully fabricated on the surface of WE43 magnesium alloy by plasma enhanced chemical vapour deposition (PECVD) technique. The microstructure and elemental composition were analyzed by transmission electron microscopy (TEM), glancing angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS), respectively. The immersion test indicated that SiC film could efficiently slow down the degradation rate of WE43 alloy in simulated body fluid (SBF) at 37 ± 1 °C. The indirect toxicity experiment was conducted using L929 cell line and the results showed that the extraction medium of SiC coated WE43 alloys exhibited no inhibitory effect on L929 cell growth. The in vitro hemocompatibility of the samples was investigated by hemolysis test and blood platelets adhesion test, and it was found that the hemolysis rate of the coated WE43 alloy decreased greatly, and the platelets attached on the SiC film were slightly activated with a round shape. It could be concluded that SiC film prepared by PECVD made WE43 alloy more appropriate to biomedical application.

  13. Surface characteristics and corrosion behaviour of WE43 magnesium alloy coated by SiC film

    Energy Technology Data Exchange (ETDEWEB)

    Li, M. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Cheng, Y., E-mail: chengyan@pku.edu.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zheng, Y.F. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Zhang, X.; Xi, T.F. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Wei, S.C. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Peking University, Beijing 100871 (China)

    2012-01-15

    Amorphous SiC film has been successfully fabricated on the surface of WE43 magnesium alloy by plasma enhanced chemical vapour deposition (PECVD) technique. The microstructure and elemental composition were analyzed by transmission electron microscopy (TEM), glancing angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS), respectively. The immersion test indicated that SiC film could efficiently slow down the degradation rate of WE43 alloy in simulated body fluid (SBF) at 37 {+-} 1 Degree-Sign C. The indirect toxicity experiment was conducted using L929 cell line and the results showed that the extraction medium of SiC coated WE43 alloys exhibited no inhibitory effect on L929 cell growth. The in vitro hemocompatibility of the samples was investigated by hemolysis test and blood platelets adhesion test, and it was found that the hemolysis rate of the coated WE43 alloy decreased greatly, and the platelets attached on the SiC film were slightly activated with a round shape. It could be concluded that SiC film prepared by PECVD made WE43 alloy more appropriate to biomedical application.

  14. SiC Conversion Coating Prepared from Silica-Graphite Reaction

    Directory of Open Access Journals (Sweden)

    Back-Sub Sung

    2017-01-01

    Full Text Available The β-SiC conversion coatings were successfully synthesized by the SiO(v-graphite(s reaction between silica powder and graphite specimen. This paper is to describe the effects on the characteristics of the SiC conversion coatings, fabricated according to two different reaction conditions. FE-SEM, FE-TEM microstructural morphologies, XRD patterns, pore size distribution, and oxidation behavior of the SiC-coated graphite were investigated. In the XRD pattern and SAD pattern, the coating layers showed cubic SiC peak as well as hexagonal SiC peak. The SiC coatings showed somewhat different characteristics with the reaction conditions according to the position arrangement of the graphite samples. The SiC coating on graphite, prepared in reaction zone (2, shows higher intensity of beta-SiC main peak (111 in XRD pattern as well as rather lower porosity and smaller main pore size peak under 1 μm.

  15. In-Situ Observation of SiC Bulk Single Crystal Growth by XRD System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In-situ analysis for SiC bulk single crystal growth was reported using vertical X-ray diffractometer system. A furnace for SiC sublimation growth combined with the XRD system which possessed three kinds of functions including topography, rocking curve measurement and crystal growth rate monitoring was developed. These functions could contribute as a powerful tool finding the optimum growth condition by dynamic observation in the crucible. In this study, the in-situ X-ray topographs succeeded to capture dynamic elongation of defects and dislocation generated in the SiC growing crystals. The in-situ rocking curve measurement reviled appearance of mosaic structure in the SiC crystal grown with high growth rate. The in-situ growth rate monitoring also succeeded very precisely using the direct X-ray beam absorption. On the base of findings and facts obtained by the in-situ observations, the importance for the SiC growth was discussed.

  16. Investigation on The Properties of Fe-Si3N4 Bonded SiC Composite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; FENG Di; PENG Dayan

    2005-01-01

    The mechanical properties of pressureless sintering Fe-Si3N4 bonded SiC and Si3 N4 bonded SiC with same manufacture process have been compared in this paper.The oxidizing mechanism of Fe-Si3 N4 bonded SiC ceramic matrix composite has been investigated especially through TG-DSC (thermo gravimetric analysis-differential scanning calorimeter) experiment. During oxidation procedure the main reaction is the oxidation of SiC and Si3N4, SiO2 which form protecting film to prevent further oxidizing. And residual iron in the samples become Fe2 O3 and Fe3O4, the oxidation kinetics at 1100 ~ 1300℃ of re-Si3 N4 bonded SiC has been studied especially. The weight gain per unit area at initial stage changes according to beeline rule, in the middle according to conic, and in the last oxidation period follows parabola rule.

  17. Highly flexible and robust N-doped SiC nanoneedle field emitters

    KAUST Repository

    Chen, Shanliang

    2015-01-23

    Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm-1, 1.55 V μm-1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. © 2015 Nature Publishing Group All rights reserved.

  18. X-ray fluorescence microtomography on a SiC nuclear fuel shell

    Energy Technology Data Exchange (ETDEWEB)

    Naghedolfeizi, M.; Chung, J.S.; Ice, G.E. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Yun, W.B.; Cai, Z.; Lai, B. [Argonne National Lab., IL (United States). Advanced Photon Source

    1998-12-31

    TRISO fuel particles contain a small kernel of nuclear fuel encapsulated by alternating layers of C and a barrier layer of SiC. The TRISO fuel particle is used in an advanced nuclear fuel where the SiC shell provides the primary barrier for radioactive elements in the kernel. The performance of this barrier is key to containment. The authors have used x-ray fluorescence microtomography to measure the trace element distribution in a SiC shell. Prior to the measurements the nuclear fuel and C layers were leached from the particle. The shell was then encapsulated by kapton tape to simplify handling. The shell was mounted on a glass fiber and measurements were made with an {approximately} 1 x 3 {micro}m{sup 2} x-ray probe on beamline 2-ID at the APS. The distribution of trace elements in the SiC shell was reconstructed after correcting the data for artifacts arising from absorption and scattering off the kapton tape. The observed trace elements are distributed in small < 1 {micro}m regions through the SiC shell. The trace elements can be attributed to radiation enhanced diffusion of elements in the kernel or to trace elements introduced during fabrication. X-ray fluorescence microtomography is an ideal tool for this work because it is a penetrating nondestructive probe sensitive to trace elements in a low Z matrix and because it provides a picture of the elemental distribution in the shell.

  19. Ag Transport Through Non-Irradiated and Irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Blanchard, James [Univ. of Wisconsin, Madison, WI (United States)

    2016-01-11

    Silicon carbide is the main barrier to diffusion of fission products in the current design of TRistuctural ISOtropic (TRISO) coated fuel particles, and Ag is one of the few fission products that have been shown to escape through this barrier. Because the SiC coating in TRISO is exposed to radiation throughout the lifetime of the fuel, understanding of how radiation changes the transport of the fission products is essential for the safety of the reactor. The goals of this project are: (i) to determine whether observed variation in integral release measurements of Ag through SiC can be explained by differences in grain size and grain boundary (GB) types among the samples; (2) to identify the effects of irradiation on diffusion of Ag through SiC; (3) to discover phenomena responsible for significant solubility of Ag in polycrystalline SiC. To address these goals, we combined experimental analysis of SiC diffusion couples with modeling studies of diffusion mechanisms through bulk and GBs of this material. Comparison between results obtained for pristine and irradiated samples brings in insights into the effects of radiation on Ag transport.

  20. Molecular systems biology of Sic1 in yeast cell cycle regulation through multiscale modeling.

    Science.gov (United States)

    Barberis, Matteo

    2012-01-01

    Cell cycle control is highly regulated to guarantee the precise timing of events essential for cell growth, i.e., DNA replication onset and cell division. Failure of this control plays a role in cancer and molecules called cyclin-dependent kinase (Cdk) inhibitors (Ckis) exploit a critical function in cell cycle timing. Here we present a multiscale modeling where experimental and computational studies have been employed to investigate structure, function and temporal dynamics of the Cki Sic1 that regulates cell cycle progression in Saccharomyces cerevisiae. Structural analyses reveal molecular details of the interaction between Sic1 and Cdk/cyclin complexes, and biochemical investigation reveals Sic1 function in analogy to its human counterpart p27(Kip1), whose deregulation leads to failure in timing of kinase activation and, therefore, to cancer. Following these findings, a bottom-up systems biology approach has been developed to characterize modular networks addressing Sic1 regulatory function. Through complementary experimentation and modeling, we suggest a mechanism that underlies Sic1 function in controlling temporal waves of cyclins to ensure correct timing of the phase-specific Cdk activities.

  1. Creep deformation of grain boundary in a highly crystalline SiC fibre.

    Science.gov (United States)

    Shibayama, Tamaki; Yoshida, Yutaka; Yano, Yasuhide; Takahashi, Heishichiro

    2003-01-01

    Silicon carbide (SiC) matrix composites reinforced by SiC fibres (SiC/SiC composites) are currently being considered as alternative materials in high Ni alloys for high-temperature applications, such as aerospace components, gas-turbine energy-conversion systems and nuclear fusion reactors, because of their high specific strength and fracture toughness at elevated temperatures compared with monolithic SiC ceramics. It is important to evaluate the creep properties of SiC fibres under tensile loading in order to determine their usefulness as structural components. However, it would be hard to evaluate creep properties by monoaxial tensile properties when we have little knowledge on the microstructure of crept specimens, especially at the grain boundary. Recently, a simple fibre bend stress relaxation (BSR) test was introduced by Morscher and DiCarlo to address this problem. Interpretation of the fracture mechanism at the grain boundary is also essential to allow improvement of the mechanical properties. In this paper, effects of stress applied by BSR test on microstructural evolution in advanced SiC fibres, such as Tyranno-SA including small amounts of Al, are described and discussed along with the results of microstructure analysis on an atomic scale by using advanced microscopy.

  2. Analysis of charge loss in nonvolatile memory with multi-layered SiC nanocrystals

    Science.gov (United States)

    Lee, Dong Uk; Lee, Tae Hee; Kim, Eun Kyu; Shin, Jin-Wook; Cho, Won-Ju

    2009-08-01

    A nonvolatile memory device with multilayered SiC nanocrystals for long-term data storage was fabricated, and its electrical properties were analyzed. The average size and density of the SiC nanocrystals, which were formed between the tunnel and control oxide layers, were approximately 5 nm and 2×1012 cm-2, respectively. The memory window of nonvolatile memory with the multilayer of SiC nanocrystals was about 2.5 V after program and erase voltages of ±12 V were applied for 500 ms, and then it was maintained at about 1.1 V for 105 s at 75 °C. The activation energy estimated from charge losses of 25% to 50% increased from 0.03 to 0.30 eV, respectively. The charge loss could be caused by a Pool-Frenkel current of holes and electrons between the SiC quantum dots and the carrier charge traps around the SiC nanocrystals embedded in SiO2 or the degradation effect of the tunnel oxide by stress induced leakage current.

  3. Pulmonary retention of ceramic fibers in silicon carbide (SiC) workers.

    Science.gov (United States)

    Dufresne, A; Loosereewanich, P; Armstrong, B; Infante-Rivard, C; Perrault, G; Dion, C; Massé, S; Bégin, R

    1995-05-01

    The fibrous inorganic content of post-mortem lung material obtained from 15 men who worked in the primary silicon carbide (SiC) industry was evaluated. Five men had neither lung fibrosis nor lung cancer (NFNC), six had lung fibrosis (LF), and four had lung fibrosis and lung cancer (LFLC). The workers had 23 to 32 years of exposure. Mean duration of exposure was 23.4 (SD 6.9) years in the NFNC group, 28.8 (SD 5.5) in the LF, and 32.3 (SD 9.0) in the LFLC group. Concentrations of SiC ceramic fibers and other fibrous minerals and angular particles were determined by transmission electron microscopy and energy dispersive spectroscopy. The geometric mean and geometric standard deviation lung concentrations of SiC ceramic fibers 0.1). Pulmonary retention of SiC fibers > or = 5 microns showed an excess in LF and LFLC cases combined versus NFNC that approached statistical significance (Mann-Whitney, p = 0.06). There was a somewhat greater difference for lung retention of ferruginous bodies between NFNC and either LF or LFLC cases (Mann-Whitney, p = 0.02). SiC fibers > or = 5 microns and angular particles containing Si and especially ferruginous bodies were found at higher concentrations in LF and LFLC than in NFNC cases.

  4. Epitaxy relationships between Ge-islands and SiC(0 0 0 1)

    Energy Technology Data Exchange (ETDEWEB)

    Ait-Mansour, K. [Faculte des Sciences, LPSE, UMR CNRS 7014, 4, rue des Freres Lumiere, 68093 Mulhouse, Cedex (France)]. E-mail: k.ait-mansour@uha.fr; Dentel, D. [Faculte des Sciences, LPSE, UMR CNRS 7014, 4, rue des Freres Lumiere, 68093 Mulhouse, Cedex (France); Kubler, L. [Faculte des Sciences, LPSE, UMR CNRS 7014, 4, rue des Freres Lumiere, 68093 Mulhouse, Cedex (France); Diani, M. [Departement de Physique, Faculte des Sciences et Techniques, LSGM, BP 416, Tanger, Maroc (Morocco); Bischoff, J.L. [Faculte des Sciences, LPSE, UMR CNRS 7014, 4, rue des Freres Lumiere, 68093 Mulhouse, Cedex (France); Bolmont, D. [Faculte des Sciences, LPSE, UMR CNRS 7014, 4, rue des Freres Lumiere, 68093 Mulhouse, Cedex (France)

    2005-03-15

    Reflection high-energy electron diffraction (RHEED) has been used to determine epitaxy relationships and in-plane orientations between Ge and SiC(0 0 0 1). Three monolayers of Ge have been deposited at 500 deg. C on a graphitized SiC (6{radical}3 x 6{radical}3)R30 deg. reconstructed surface, this surface supporting epitaxial Ge island growth in a Volmer-Weber mode. Nucleation of relaxed Ge-islands gives rise to transmission electron diffraction patterns allowing to deduce that pure Ge grows according to only one epitaxy relationship Ge{l_brace}1 1 1{r_brace}//SiC(0 0 0 1). These {l_brace}1 1 1{r_brace}-Ge-islands have two in-plane orientations, a preferential one, Ge<-1-12>//SiC<1-100> and a minority one, Ge<-1-12>//SiC<10-10>, deduced one from the other by a 30 deg. rotation around the <1 1 1>-Ge (or [0 0 0 1]-SiC) growth axis. Due to the three-fold symmetry of the {l_brace}1 1 1{r_brace}-Ge plane, each in-plane orientation is degenerated into two twin orientations, differing by a 180 deg. angle around Ge<111>.

  5. Pore Formation Process of Porous Ti3SiC2 Fabricated by Reactive Sintering

    Directory of Open Access Journals (Sweden)

    Huibin Zhang

    2017-02-01

    Full Text Available Porous Ti3SiC2 was fabricated with high purity, 99.4 vol %, through reactive sintering of titanium hydride (TiH2, silicon (Si and graphite (C elemental powders. The reaction procedures and the pore structure evolution during the sintering process were systematically studied by X-ray diffraction (XRD and scanning electron microscope (SEM. Our results show that the formation of Ti3SiC2 from TiH2/Si/C powders experienced the following steps: firstly, TiH2 decomposed into Ti; secondly, TiC and Ti5Si3 intermediate phases were generated; finally, Ti3SiC2 was produced through the reaction of TiC, Ti5Si3 and Si. The pores formed in the synthesis procedure of porous Ti3SiC2 ceramics are derived from the following aspects: interstitial pores left during the pressing procedure; pores formed because of the TiH2 decomposition; pores formed through the reactions between Ti and Si and Ti and C powders; and the pores produced accompanying the final phase synthesized during the high temperature sintering process.

  6. Some fundamental aspects of boiling in nuclear reactors; Quelques aspects fondamentaux de l'ebullition dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Mondin, H.; Lavigne, P.; Semeria, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1964-07-01

    oscillation, the conditions of burnout are compared with those obtained under steady conditions. The burn-out flux following uniform 'stopped' heating has been studied in a channel containing still water. The flux shows a maximum as a function of unsaturation. The influence of the geometry and the nature of the metal was investigated. 4 - Output Oscillations: Using a low pressure (8 atm) loop, the influence of various parameters on the periods of output oscillations in a boiling channel on the thresholds at which they appear, was studied. Some new aspects of this complex phenomena were observed and are reported. (authors) [French] On indique les principaux resultats obtenus a Grenoble depuis quatre ans dans le domaine des mecanismes de l'ebullition et des phenomenes connexes dans les reacteurs nucleaires. 1 - OBSERVATION DE L'EBULLITION: Par photographie et cinematographie ultrarapide (8000 images par seconde maximum) on a observe l'ebullition en vase ou en canal jusqu'a 140 kg/cm{sup 2}. On a denombre les populations de germes (sites) generateurs de bulles et obtenu une correlation donnant leur nombre par unite de surface en fonction du flux thermique et de la pression. Le diametre des bulles se detachant de la paroi a ete etudie jusqu'a 140 kg/cm{sup 2}. On a mis en evidence trois types de bulles: - Les bulles en equilibre dont le diametre suit la formule de Fritz et Ende, - Les bulles d'ebullition dont le diametre diminue rapidement avec la pression (1/100 mm a 140 kg/cm{sup 2}), - Les coalescences apparaissant en liquide sature au-dessus de 15 W/cm{sup 2} et dont la proportion est independante de la pression. Par visualisation en strioscopie on observe les mouvements du film thermique associes a l'amorcage des germes, au depart et a la condensation des bulles; les mecanismes responsables de l'excellent transfert de chaleur ont pu ainsi etre precises. 2 - PERTES DE PRESSION EN ECOULEMENT DIPHASE: On a etabli un modele de

  7. Facteurs influençant l'initiation au traitement antirétroviral des personnes vivant avec le VIH dans les Centres de Traitement Agréés de Bamenda et de Bertoua au Cameroun

    Science.gov (United States)

    Mbopi-Keou, Francois-Xavier; Voundi, Esther Voundi; Kalla, Ginette Claude Mireille; Emah, Irène; Angwafo, Fru; Muna, Walinjom

    2014-01-01

    Introduction L'objectif de ce travail était de déterminer les facteurs influençant l'initiation au traitement antirétroviral des personnes vivant avec le VIH (PVVIH) dans les centres de traitements agrées (CTA) de Bamenda et de Bertoua au Cameroun. Méthodes Il s'agissait d'une étude transversale, analytique réalisée de Janvier à Avril 2011, dans les CTA de Bamenda et de Bertoua. Pour cette étude, nous avons obtenu une clairance éthique. Résultats Nous avons étudiés 460 dossiers de patients séropositifs en phase d'initiation au traitement antirétroviral dans les CTA de Bamenda et de Bertoua, 53,9% et 46,1% respectivement. L ‘âge médian était de 36 ans. La plupart des séropositifs à Bertoua (41) avaient fait un dépistage volontaire du VIH par rapport à ceux de Bamenda (22) (p= 0.008). Il y ‘avait plus de VIH de type 1 et 2 dans le CTA de Bamenda (15) par rapport à Bertoua (3) (p= 0.011). La majorité des patients était classé au stade clinique II à Bamenda (54,0%) tandis qu ‘à Bertoua le stade clinique III était prédominant (52,4%) (p = 0,000). Le taux médian de CD4 était de 133 cellules/mm3 dans le CTA de Bamenda et de 175 cellules/mm3 à Bertoua (p = 0,008). La Zidovudine était plus prescrit à Bamenda et le Ténofovir à Bertoua (p = 0,000). L ‘Efavirenz était plus prescrit à Bertoua tandis que la Névirapine l ‘était plus à Bamenda (p = 0,000). Le Lopinavir/r était plus prescrit à Bamenda qu ‘à Bertoua (p = 0,017). Conclusion Il apparait urgent de standardiser la prise en charge des PVVIH dans les CTA du Cameroun. PMID:25184023

  8. KEJAHATAN PORNOGRAFI Upaya Pencegahan dan Penanggulangannya di Kabupaten Ponorogo

    Directory of Open Access Journals (Sweden)

    Irma Rumtianing Uswatul Hanifah

    2013-12-01

    Full Text Available Pemerintah telah mengeluarkan undang-undang No 44 Tahun 2008 tentang pornografi. Tujuan dari undang-undang tersebut salah satunya mewujudkan dan memelihara tatanan kehidupan masyarakat yang beretika, berkepribadian luhur, menjungjung tinggi nilai-nilai Ketuhanan Yang Maha Esa, serta menghormati harkat dan martabat kemanusiaan. Dalam perkembangannya, materi pornografi mengalami pertumbuhan dan penyebaran yang pesat seiring dengan perkembangan dan kemajuan teknologi informasi dan komunikasi. Peredaran dan penyebaran film porno kini semakin pesat karena ditopang dengan kecanggihan sarana informasi dan komunikasi salah satunya media internet yang bisa diakses oleh masyarakat pada setiap saat. Tulisan berikut akan mengkaji bagaimana upaya dan trategi yang dilakukan oleh Pemerintah Kabupaten Ponorogo dalam mencegah dan menanggulangi kejahatan pornografi di Kabupaten Ponorogo, apa hambatan dan bagaimana solusi dalam pencegahan serta penanggulangan kejahatan pornografi di Kabupaten Ponorogo serta bagaimana formulasi kebijakan untuk pencegahan dan penanggulangan kejahatan pornografi di Kabupaten Ponorogo. Kata kunci: Pornografi, Polres, KP3A

  9. Perbandingan Akurasi Pengukuran Suhu dan Kelembaban Antara Sensor DHT11 dan DHT22

    Directory of Open Access Journals (Sweden)

    Arief Hendra Saptadi

    2014-11-01

    Full Text Available Suhu dan kelembaban merupakan dua objek pengukuran yang acapkali terdapat di dalam sistem akuisisi data. Terdapat banyak piranti sensor yang berfungsi untuk mengukur dua objek tersebut dan akurasi merupakan salah satu parameter yang dapat digunakan untuk memilihnya. DHT11 dan DHT22 adalah sensor seri DHT dari Aosong Electronics yang dapat melakukan pengukuran suhu dan kelembaban secara serempak dengan keluaran digital. Informasi tentang akurasi terdapat di dalam lembar data keduanya. Kendati pun demikian informasi tersebut tidak menggambarkan kondisi sesungguhnya saat dioperasikan pada lokasi maupun platform tertentu. Tujuan dari penelitian ini adalah untuk membandingkan akurasi dari DHT11 dan DHT22 dalam pengukuran suhu dan kelembaban saat dioperasikan di dalam maupun di luar ruangan, menggunakan platform ATMEL AVR dan Arduino. Berdasarkan pengujian yang telah dilakukan, DHT22 memiliki akurasi yang lebih baik daripada DHT11 dengan galat relatif pengukuran suhu 4% dan kelembaban 18%. DHT11 sebaliknya memiliki rentang galat yang lebih lebar sebesar 1 – 7% dan 11 – 35%, masing-masing untuk pengukuran suhu dan kelembaban. Perbedaan lokasi dan platform tidak memberikan pengaruh pada hasil pengukuran. Galat pengukuran kelembaban yang masih di atas 10% menunjukkan perlunya kalibrasi ulang. Di masa mendatang, selain akurasi, kepresisian juga perlu diuji menggunakan penghitungan simpangan baku pada hasil-hasil pengukuran.

  10. KANDUNGAN ASAM AMINO, TAURIN, MINERAL MAKRO-MIKRO, DAN VITAMIN B12 UBUR-UBUR (Aurelia aurita SEGAR DAN KERING

    Directory of Open Access Journals (Sweden)

    - - Nurjanah

    2014-06-01

    Full Text Available Tujuan penelitian adalah menentukan komposisi gizi, asam amino, taurin, mineral makro dan mikro,dan vitamin B12 pada ubur-ubur (Aurelia aurita segar dan kering. Asam amino esensial pada ubur-uburyaitu arginina, leusina, valina, treonina, lisina, isoleusina, fenilalanina, metionina, dan histidina, sedangkanasam amino non esensial yaitu asam glutamat, glisina, asam aspartat, serina, alanina, dan tirosina. Asamamino esensial tertinggi segar dan kering adalah arginina sebesar 1,72% (bk dan 1,44% (bk dan terendahhistidina yaitu sebesar 0,19% (bk dan 0,13% (bk. Asam amino non esensial segar dan kering tertinggiadalah asam glutamat dan glisina yaitu sebesar 3,26% (bk dan 2,62% (bk dan terkecil tirosina sebesar0,38% (bk dan 0,41% (bk. Taurin segar sebesar 2,68% (bk dan kering sebesar 0,67% (bk. Mineral makrotertinggi segar dan kering adalah natrium yaitu 180.092,1 ppm (bk dan 111.209,4 ppm (bk, terkecil adalahkalsium yaitu 5.750,2 ppm (bk dan 11,1 ppm (bk. Mineral mikro tertinggi segar dan kering adalah iodium yaitu8.291,5 ppm (bk dan 1.800 ppm (bk dan yang terkecil adalah tembaga yaitu 1,1 ppm (bk dan 0,6 ppm (bk.Vitamin B12 segar adalah 396,6 μm/100 g (bk dan kering 63,5 μm/100 g (bk.Kata kunci: asam amino, mineral, taurin, ubur-ubur (Aurelia aurita, vitamin B12

  11. IDENTIFIKASI DAN TEKNIK PENGENDALIAN HAMA DAN PENYAKIT BIBIT KRANJI (Pongamia pinnata

    Directory of Open Access Journals (Sweden)

    Tati Suharti

    2015-12-01

    Full Text Available Salah satu faktor pembatas dalam keberhasilan tanaman untuk tumbuh optimal yaitu adanya serangan hama dan penyakit. Identifikasi hama dan penyakit penting dilakukan karena berkaitan dengan teknik pengendalian. Tujuan penelitian ini adalah untuk mengetahui jenis hama dan penyakit yang menyerang bibit kranji (Pongamia pinnata dan teknik pengendaliannya. Metode penelitian meliputi identifikasi jenis hama dan penyakit serta teknik pengendalian dengan menggunakan pestisida biologi dan kimia. Hasil penelitian menunjukan, hama yang menyerang bibit kranji antara lain belalang (Valanga nigricornis, ulat grayak (Spodoptera sp., ulat jengkal (Hyposidra talaca dan ulat penggulung (Syllepta sp. sedangkan patogen yang menyebabkan penyakir hawar daun yaitu Phytophthora sp. Teknik pengendalian hama bibit kranji dengan menggunakan larutan ekstrak biji mahoni atau insektisida Bacillus thuringiensis sedangkan teknik pengendalian penyakit menggunakan larutan ekstrak biji mahoni, larutan ekstrak daun cengkeh atau benomil

  12. SIMULATION ET MODELISATION DE LA VARIATION DE LA MOBILITE DE HALL DES PHOTOELECTRONS EN FONCTION DE LA TEMPERATURE DANS LES CRISTAUX DE n-ZnSe :Zn IRRADIES AVEC DES ELECTRONS ENERGETIQUES

    Directory of Open Access Journals (Sweden)

    D DJOUADI

    2007-12-01

    Full Text Available Dans l’intervalle de températures [77..300 K] a été mesurée la mobilité de Hall des électrons d’équilibre et des photoélectrons dans les cristaux de n-ZnSe :Zn irradiés avec un faisceau d’électrons d’énergie E=1,3 MeV et dont la dose d’irradiation varie entre 2,73 1016 et 5.19 1017 électrons/cm2 . Le comportement de la mobilité des photoélectrons s’explique parfaitement dans le cadre d’un modèle à deux-barrières d’un semi-conducteur inhomogène représentant une matrice faiblement ohmique contenant des inclusions fortement ohmiques (clusters. En se basant sur les théories de Shik et de Petrossiyan , une expression approximative de la mobilité de Hall a été obtenue. Il a été montré que ce modèle fonctionne parfaitement pour les petites doses d’irradiation. Lorsque la dose dépasse une certaine valeur critique ( D= 2.98 1017 électrons /cm2 le modèle considéré passe au modèle du potentiel à relief aléatoire.

  13. Low Shear Strength and Shear-Induced Failure in Ti3SiC2

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Shear strength and shear-induced Hertzian contact damage in Ti3SiC2 were investigated using double-notched-beamspecimen and steel spherical indenter, respectively. The shear strength of 40 MPa that was only about 10% of bendingstrength was obtained for this novel ceramic. The SEM fractograph of specimens failed in shear test indicated acombination of intergranular and transgranular fracture. Under a contact load, plastic indent without cone crackcould be formed on the surface of Ti3SiC2 sample. Optical observation on side view showed half-circle cracks aroundthe damage zone below the indent, and the crack shape was consistent with the contrail of the principal shearingstress. The low shear strength and the shearing-activated intergranular sliding were confirmed being the key factorsfor failure in Ti3SiC2.

  14. Development of a PSpice Modeling Platform for SiC Power MOSFET Modules

    DEFF Research Database (Denmark)

    Ceccarelli, Lorenzo; Iannuzzo, Francesco; Nawaz, Muhammad

    2017-01-01

    The aim of this work is to present a PSpice implementation for a well-established and compact physics-based SiC MOSFET model, including a fast, experimental-based parameter extraction procedure in a MATLAB GUI environment. The model, originally meant for single-die devices, has been used to simul......The aim of this work is to present a PSpice implementation for a well-established and compact physics-based SiC MOSFET model, including a fast, experimental-based parameter extraction procedure in a MATLAB GUI environment. The model, originally meant for single-die devices, has been used...... to simulate the performance of high current rating (above 100 A), multi-chip SiC MOSFET modules, both for static and switching behavior. Therefore, the simulation results have been validated experimentally in a wide range of operating conditions, including high temperatures, gate resistance and stray elements...

  15. Microporous layer based on SiC for high temperature proton exchange membrane fuel cells

    Science.gov (United States)

    Lobato, Justo; Zamora, Héctor; Cañizares, Pablo; Plaza, Jorge; Rodrigo, Manuel Andrés

    2015-08-01

    This work reports the evaluation of Silicon Carbide (SiC) for its application in microporous layers (MPL) of HT-PEMFC electrodes and compares results with those obtained using conventional MPL based on Vulcan XC72. Influence of the support load on the MPL prepared with SiC was evaluated, and the MPL were characterized by XRD, Hg porosimetry and cyclic voltammetries. In addition, a short lifetest was carried out to evaluate performance in accelerated stress conditions. Results demonstrate that SiC is a promising alternative to carbonaceous materials because of its higher electrochemical and thermal stability and the positive effect on mass transfer associated to its different pore size distribution. Ohmic resistance is the most significant challenge to be overcome in further studies.

  16. Fluorescent SiC with pseudo-periodic moth-eye structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Aijaz, Imran; Ou, Haiyan

    2012-01-01

    material much superior to the phosphors in terms of high color rendering index value and long lifetime. The light extraction efficiency of the fluorescent SiC based all semiconductor LED light sources is usually low due to the large refractive index difference between the semiconductor and air. In order...... to enhance the extraction efficiency, we present a simple method to fabricate the pseudo-periodic moth-eye structures on the surface of the fluorescent SiC. A thin gold layer is deposited on the fluorescent SiC first. Then the thin gold layer is treated by rapid thermal processing. After annealing, the thin...... gold layer turns into discontinuous nano-islands. The average size of the islands is dependent on the annealing condition which could be well controlled. By using the reactive-ion etching, pseudo-periodic moth-eye structures would be obtained using the gold nano-islands as a mask layer. Reactive...

  17. The diffusion welding of 7075Al-3%SiC particles reinforced composites

    Science.gov (United States)

    Aydin, M.; Gürler, R.; Türker, M.

    2009-02-01

    A group of 3% SiC particle reinforced Al-7075 alloys was diffusion joined at 560°C between 1 h and 2 h durations under 2 MPa applied pressure in a vacuum of 2 × 10-3 Pa. Optical microscopy and SEM-EDS studies were used to characterise the weldment and the fracture surfaces of all samples investigated. A non-planar interface formation was observed at the bond interface. The maximum shear strength of 137 MPa was obtained with the composite 7075-3% SiC joined for two hours, which is 92% of the shear strength of the parent material. The fracture surface of the 7075-3% SiC composites displayed a non-planar fracture surfaces with some plastic deformation.

  18. Surface Oxidation of Al2O3/SiC Nanocomposite: Phase Transformation and Microstructure

    Institute of Scientific and Technical Information of China (English)

    Cai Shu; Peng Zhenzhen; Feng Jie; Lu Feng

    2005-01-01

    The surface oxidation behavior of pressureless sintered Al2O3/SiC nanocomposite was studied from 1000 to 1400 ℃ for more than 10 h in air. Weight gain during the process of heat treatment was measured by TG analysis. Phase transformation and microstructure changes of these specimens due to oxidation were investigated with X-ray diffraction (XRD), SEM and EDX technology. Thermogravimetric analysis show that the weight gain as a result of oxidation of SiC become significant above 1200 ℃. In the range of 1000~1300 ℃, the SiC grits are usually coated with a layer of amorphous silica after oxidation. Above 1300 ℃, the amorphous silica reacted with alumina matrix and formed mullite or crystallized into cristobalite. The rate of oxidation depends on the formation of dense cristobalite film. Large amount of needle-like mullite and alumina crystals are formed on the surface after oxidation at 1400 ℃.

  19. Al4SiC4 wurtzite crystal: Structural, optoelectronic, elastic, and piezoelectric properties

    Directory of Open Access Journals (Sweden)

    L. Pedesseau

    2015-12-01

    Full Text Available New experimental results supported by theoretical analyses are proposed for aluminum silicon carbide (Al4SiC4. A state of the art implementation of the density functional theory is used to analyze the experimental crystal structure, the Born charges, the elastic properties, and the piezoelectric properties. The Born charge tensor is correlated to the local bonding environment for each atom. The electronic band structure is computed including self-consistent many-body corrections. Al4SiC4 material properties are compared to other wide band gap wurtzite materials. From a comparison between an ellipsometry study of the optical properties and theoretical results, we conclude that the Al4SiC4 material has indirect and direct band gap energies of about 2.5 eV and 3.2 eV, respectively.

  20. Investigation of reactivity between SiC and Nb-1Zr in planned irradiation creep experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, C.A.; Hamilton, M.L.; Jones, R.H.

    1997-08-01

    Thermodynamic calculations and diffusion couple experiments showed that SiC and Nb-1Zr were reactive at the upper range of temperatures anticipated in the planned irradiation creep experiment. Sputter-deposited aluminum oxide (Al{sub 2}O{sub 3}) was selected as a diffusion barrier coating. Experiments showed that although the coating coarsened at high temperature it was an effective barrier for diffusion of silicon from SiC into Nb-1Zr. Therefore, to avoid detrimental reactions between the SiC composite and the Nb-1Zr pressurized bladder during the planned irradiation creep experiment, a coating of Al{sub 2}O{sub 3} will be required on the Nb-1Zr bladder.

  1. Pseudo Dirac dispersion in Mn-intercalated graphene on SiC

    KAUST Repository

    Kahaly, M. Upadhyay

    2013-07-01

    The atomic and electronic structures of bulk C6Mn, bulk C 8Mn, and Mn-intercalated graphene on SiC(0 0 0 1) and SiC(0001̄) are investigated by density functional theory. We find for both configurations of Mn-intercalated graphene a nonmagnetic state, in agreement with the experimental situation for SiC(0 0 0 1), and explain this property. The electronic structures around the Fermi energy are dominated by Dirac-like cones at energies consistent with data from angular resolved photoelectron spectroscopy [Gao et al., ACS Nano. 6 (2012) 6562]. However, our results demonstrate that the corresponding states trace back to hybridized Mn d orbitals, and not to the graphene. © 2013 Elsevier B.V. All rights reserved.

  2. Layered SiC sheets: a potential catalyst for oxygen reduction reaction.

    Science.gov (United States)

    Zhang, P; Xiao, B B; Hou, X L; Zhu, Y F; Jiang, Q

    2014-01-22

    The large-scale practical application of fuel cells cannot come true if the high-priced Pt-based electrocatalysts for oxygen reduction reaction (ORR) cannot be replaced by other efficient, low-cost, and stable electrodes. Here, based on density functional theory (DFT), we exploited the potentials of layered SiC sheets as a novel catalyst for ORR. From our DFT results, it can be predicted that layered SiC sheets exhibit excellent ORR catalytic activity without CO poisoning, while the CO poisoning is the major drawback in conventional Pt-based catalysts. Furthermore, the layered SiC sheets in alkaline media has better catalytic activity than Pt(111) surface and have potential as a metal-free catalyst for ORR in fuel cells.

  3. A Fast Electro-Thermal Co-Simulation Modeling Approach for SiC Power MOSFETs

    DEFF Research Database (Denmark)

    Ceccarelli, Lorenzo; Bahman, Amir Sajjad; Iannuzzo, Francesco

    The purpose of this work is to propose a novel electro-thermal co-simulation approach for the new generation of SiC MOSFETs, by development of a PSpice-based compact and physical SiC MOSFET model including temperature dependency of several parameters and a Simulink-based thermal network. The PSpice...... electrical model is capable to estimate the switching behavior and the energy losses of the device accurately under a wide range of operational conditions, including high temperature operations, within a relatively fast simulation time (few seconds). The the thermal network elements are extracted from...... the FEM simulation of the DUT’s structure, performed in ANSYS Icepack. A MATLAB script is used to process the simulation data and feed the needed settings and parameters back into the simulation. The parameters for a CREE 1.2 kV/30 A SiC MOSFET have been identified and the electro-thermal model has been...

  4. Cl-intercalated graphene on SiC: Influence of van der Waals forces

    KAUST Repository

    Cheng, Yingchun

    2013-01-01

    The atomic and electronic structures of Cl-intercalated epitaxial graphene on SiC are studied by first-principles calculations. By increasing the Cl concentration, doping levels from n-type to slightly p-type are achieved on the SiC(0001) surface, while a wider range of doping levels is possible on the SiC(0001̄) surface. We find that the Cl atoms prefer bonding to the substrate rather than to the graphene. By varying the Cl concentration the doping level can be tailored. Consideration of van der Waals forces improves the distance between the graphene and the substrate as well as the binding energy, but it is not essential for the formation energy. For understanding the doping mechanism the introduction of non-local van der Waals contributions to the exchange correlation functional is shown to be essential. Copyright © EPLA, 2013.

  5. Origin of the high p-doping in F intercalated graphene on SiC

    KAUST Repository

    Cheng, Yingchun

    2011-08-04

    The atomic and electronic structures of F intercalated epitaxialgraphene on a SiC(0001) substrate are studied by first-principles calculations. A three-step fluorination process is proposed. First, F atoms are intercalated between the graphene and the SiC, which restores the Dirac point in the band structure. Second, saturation of the topmost Si dangling bonds introduces p-doping up to 0.37 eV. Third, F atoms bond covalently to the graphene to enhance the p-doping. Our model explains the highly p-doped state of graphene on SiC after fluorination [A. L. Walter et al., Appl. Phys. Lett. 98, 184102 (2011)].

  6. Methods for growth of relatively large step-free SiC crystal surfaces

    Science.gov (United States)

    Neudeck, Philip G. (Inventor); Powell, J. Anthony (Inventor)

    2002-01-01

    A method for growing arrays of large-area device-size films of step-free (i.e., atomically flat) SiC surfaces for semiconductor electronic device applications is disclosed. This method utilizes a lateral growth process that better overcomes the effect of extended defects in the seed crystal substrate that limited the obtainable step-free area achievable by prior art processes. The step-free SiC surface is particularly suited for the heteroepitaxial growth of 3C (cubic) SiC, AlN, and GaN films used for the fabrication of both surface-sensitive devices (i.e., surface channel field effect transistors such as HEMT's and MOSFET's) as well as high-electric field devices (pn diodes and other solid-state power switching devices) that are sensitive to extended crystal defects.

  7. Layered SiC Sheets: A Potential Catalyst for Oxygen Reduction Reaction

    Science.gov (United States)

    Zhang, P.; Xiao, B. B.; Hou, X. L.; Zhu, Y. F.; Jiang, Q.

    2014-01-01

    The large-scale practical application of fuel cells cannot come true if the high-priced Pt-based electrocatalysts for oxygen reduction reaction (ORR) cannot be replaced by other efficient, low-cost, and stable electrodes. Here, based on density functional theory (DFT), we exploited the potentials of layered SiC sheets as a novel catalyst for ORR. From our DFT results, it can be predicted that layered SiC sheets exhibit excellent ORR catalytic activity without CO poisoning, while the CO poisoning is the major drawback in conventional Pt-based catalysts. Furthermore, the layered SiC sheets in alkaline media has better catalytic activity than Pt(111) surface and have potential as a metal-free catalyst for ORR in fuel cells.

  8. Friction stir spot welding of 2024-T3 aluminum alloy with SiC nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Paidar, Moslem; Sarab, Mahsa Laali [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-01-15

    In this study, the Friction stir spot welding (FSSW) of 2024-T3 aluminum alloy with 1.6 mm thickness was investigated. The effects of the silicon carbide (SiC) nanoparticles on the metallurgical and mechanical properties were discussed. The effects of particles on tension shear and wear tests were also investigated. The process was conducted at a constant rotational speed of 1000 rpm. Results showed that adding SiC nanoparticles to the weld during FSSW had a major effect on the mechanical properties. In fact, the addition of nanoparticles as barriers prevented grain growth in the Stir zone (SZ). The data obtained in the tensile-shear and wear tests showed that tensile-shear load and wear resistance increased with the addition of SiC nanoparticles, which was attributed to the fine grain size produced in the SZ.

  9. Scalable nanostructuring on polymer by a SiC stamp: optical and wetting effects

    DEFF Research Database (Denmark)

    Argyraki, Aikaterini; Lu, Weifang; Petersen, Paul Michael;

    2015-01-01

    surface. The reflectance of SiC can be reduced down to 0.5% when the ~600nm nanostructures are applied on the surface (bare surface reflectance 25%). The texture of the green SiC color is changed when the different nanostructures are apparent. The ~600nm SiC nanostructures are replicated on polymer...... from 68 (bare) to 123 (nanostructured) degrees. The optical effect on the polymer surface can be maximized by applying a thin aluminum (Al) layer coating on the nanostructures (bare polymer reflectance 11%, nanostructured polymer reflectance 5%, Al coated nanostructured polymer reflectance 3......A method for fabricating scalable antireflective nanostructures on polymer surfaces (polycarbonate) is demonstrated. The transition from small scale fabrication of nanostructures to a scalable replication technique can be quite challenging. In this work, an area per print corresponding to a 2-inch...

  10. Heavy ion-induced damage in SiC Schottky barrier diode

    Energy Technology Data Exchange (ETDEWEB)

    Kamezawa, C. [Japan Aerospace Exploration Agency, Tsukuba Space Center, 2-1-1 Sengen, Ibaraki 305-8505 (Japan)]. E-mail: kamezawa.chihiro@jaxa.jp; Sindou, H. [Japan Aerospace Exploration Agency, Tsukuba Space Center, 2-1-1 Sengen, Ibaraki 305-8505 (Japan); Hirao, T. [Japan Atomic Energy Research Institute, Gunma 370-1292 (Japan); Ohyama, H. [Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Kuboyama, S. [Japan Aerospace Exploration Agency, Tsukuba Space Center, 2-1-1 Sengen, Ibaraki 305-8505 (Japan)

    2006-04-01

    Silicon carbide (SiC) is a very promising material for future electronic devices. Also it is an attractive material for space applications, that require long-term endurance and higher efficiency, where tolerance to space radiations is a major problem. In this study, we have performed some irradiation examinations and evaluations on a commercial SiC Schottky barrier diode by looking at the damage caused by ion incidence using heavy ions. Ions of Xe, Kr, Ar, Ne, and N, with specific energies, were used in the irradiation process. Sudden breakdown condition at higher bias voltage and gradual damage created by heavy ion incidence were confirmed. The collected charge spectra were also obtained and revealed mechanisms that resulted to permanent damage. The observed anomalous charge collection was an essential factor for the susceptibility. This indicates a problem that need to be solved in the future for SiC space application.

  11. Fabrication Of Al 2024/SiC Nanocomposite with Al and Cu Pure Coatings

    Directory of Open Access Journals (Sweden)

    P. Melali

    2015-06-01

    Full Text Available Composites find an important place as new advanced materials in last decades; those especially produced with nanoparticles reinforcements, attracts researchers and a number of researches were executed on this topic. In this study, Al-base 2024 alloy composites reinforced with SiC nanoparticles were fabricated and the effects of two different coating materials were investigated. Coatings were pure Al and Cu powder with constant grain particle size. The results show that the Al coating has impacts on grain size and the interface layer between reinforcement and matrix. The mechanism of formation of interface layer between SiC nanoparticles and the Al-base 2024 matrix with reinforced with Cu coated SiC particles is quite different.

  12. ToF-MEIS stopping measurements in thin SiC films

    Energy Technology Data Exchange (ETDEWEB)

    Linnarsson, M.K., E-mail: marga@kth.se [KTH Royal Institute of Technology, School of Information and Communication Technology, Integrated Circuits and Devices, P.O. Box E229, SE-16440 Kista-Stockhom (Sweden); Khartsev, S. [KTH Royal Institute of Technology, School of Information and Communication Technology, Integrated Circuits and Devices, P.O. Box E229, SE-16440 Kista-Stockhom (Sweden); Primetzhofer, D.; Possnert, G. [Uppsala University, Ångström Laboratory, Dept. of Physics and Astronomy, Ion Physics, P.O. Box 534, SE-751 21 Uppsala (Sweden); Hallén, A. [KTH Royal Institute of Technology, School of Information and Communication Technology, Integrated Circuits and Devices, P.O. Box E229, SE-16440 Kista-Stockhom (Sweden)

    2014-08-01

    Electronic stopping in thin, amorphous, SiC films has been studied by time-of-flight medium energy ion scattering and conventional Rutherford backscattering spectrometry. Amorphous SiC films (8, 21 and 36 nm) were prepared by laser ablation using a single crystalline silicon carbide target. Two kinds of substrate films, one with a lower atomic mass (carbon) and one with higher atomic mass (iridium) compared to silicon has been used. Monte Carlo simulations have been used to evaluate electronic stopping from the shift in energy for the signal scattered from Ir with and without SiC. The two kinds of samples are used to illustrate the strength and challenges for ToF-MEIS compared to conventional RBS.

  13. The Oxidation Rate of SiC in High Pressure Water Vapor Environments

    Science.gov (United States)

    Opila, Elizabeth J.; Robinson, R. Craig

    1999-01-01

    CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for Sic in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent of one. Silica growth on Sic is therefore limited by transport of molecular water vapor through the silica scale.

  14. ANALISIS TINGKAT KEPUASAN DAN HARAPAN PASEN TERHADAP PELAYANAN PUSKESMAS DAN RUMAH SAKIT DAERAH PROVINSI DIY

    Directory of Open Access Journals (Sweden)

    Sunarto Sunarto

    2010-10-01

    Full Text Available Kepuasan merupakan perasaan seseorang mengenai kesenangan atau kekecewaan sebagai hasil membandingkan antara kinerja dan harapan. Jumlah kunjungan Puskesmas tahun 2007 sebesar 3.094.027 pasien yang terdiri dari 3.076442 rawat jalan dan 17.585 rawat inap. Penelitian untuk mengentahui gambaran tingkat kepuasan dan untuk mengetahui perbedaan tingkat kepuasan dan harapan pasien yang mendapatkan pelayanan Puskemas dan rumah sakit menurut wilayah Kabupatet / Kota di Propinsi DIY Penelitian ini merupakan penelitian deskriptif analitik dengan menggunakan rancangan cros sectional. Instrumen penelitian yang digunakan adalah kuisioner dengan 35 item pernyataan yang diambil dari atribut-atribut SERVQUAL dalam 5 dimensi. Total sampel untuk lima Kabupaten Kota sebanyak 1000, masing-masing Kabupaten Kota 200. Penelitian ini dilakukan terhadap pasien yang menerima pelayanan kesehatan di Puskesmas dan Rumah Sakit Daerah di Kabupaten-Kota Daerah Istimewa Yogyakarta. Penilaian tingkat kepuasan pasien ketika mereka berobat ke Puskesmas dan Rumah Sakit di Propinsi DIY, dengan menggunakan skala O sampai 4. Hasilnya adalah dimensi tangibles, rata-rata kepuasan pasien (2,96 cukup dan harapan pasien (3,38 pada dimensi reliability, rata-rata kepuasan pasien (3,01 bagus dan harapan pasien (3,40. Pada dimensi responsiveness, rata-rata kepuasan pa-sien (3,07 bagus dan harapan pasien (3,42. Dimensi assurance, rata-rata kepuasan pasien (3, 1 0 bagus dan harapan pasien (3 ,42. pada dimensi emphaty, rata-rata kepuasan pasien (3,02 bagus dan harapan pasien (3,35. Hasil uji statistik didapatkan nilai p > 0.05, berarti pada alpha 5%, dapat disimpulkan bahwa tidak terdapat perbedaan tingkat kepuasan diantara kelima wilayah kabupaten/kota di DIY. Penilaian tingkat kepuasan pasien, ketika mereka berkunjung ke Puskesmas dan Rumah Sakit di DIY secara rata-rata bagus dan tidak ada perbedaan tingkat kepuasan menurut wilayah Kabupaten-Kota di Propinsi DIY. Kata Kunci : Kepuasan, harapan

  15. Mechanism of Enhancement in Electromagnetic Properties of MgB2 by Nano SiC Doping

    NARCIS (Netherlands)

    Dou, S.X.; Shcherbakova, O.; Yeoh, W.K.; Kim, J.H.; Soltanian, S.; Wang, X.L.; Senatore, C.; Flukiger, R.; Dhallé, M.; Husnjak, O.; Babic, E.

    2007-01-01

    A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small grain size, and nanoinclusions induced by C incorporation and lo

  16. Efficiency and Cost Comparison of Si IGBT and SiC JFET Isolated DC/DC Converters

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup; Török, Lajos; Munk-Nielsen, Stig

    2013-01-01

    . An efficiency of above 97 % for the SiC JFET and over 90 % for the SI IGBT converter was measured. Cost differences between the two converters have been analyzed, showing that 772 days of operation are needed for the SiC converter costs to break even with the Si IGBT converter costs....

  17. STRATEGI PERSONAL BRANDING FOTOGRAFER HOTEL DAN RESORT

    OpenAIRE

    GUSTAFIAN, THOMAS HENRY ADRIAN

    2014-01-01

    Identitas brand menjadi masalah penting dalam lingkungan bisnis yang semakin kompleks dan penuh dengan persaingan. Salah satu cara yang dapat dilakukan seorang entrepreneur untuk menunjukkan identitas brand adalah melalui personal branding. Strategi personal branding sangat dipengaruhi oleh konsep diri dan strategi komunikasi yang dimiliki oleh seorang entrepreneur. Tulisan ini menggambarkan bagaimana strategi personal branding mempengaruhi keberhasilan seorang entrepreneur

  18. Dhenggung Asmarandana dan Dhegung Banten: Sebuah Komparasi

    Directory of Open Access Journals (Sweden)

    Teguh -

    2013-11-01

    Full Text Available The Comparation of Dhenggung Asmarandana and Dhegung Banten. Penelitian ini membahas perbandinganantara gending Dhenggung Asmaradana gaya Surakarta dengan gending Dhegung Banten gaya Yogyakarta.Berdasarkan penelitian dapat disimpulkan bahwa kedua gending memiliki persamaan dan perbedaan. Persamaankeduanya terletak pada laras, pathet, bentuk gendhing, struktur gendhing, serta balungan gending. Sedangkanperbedaannya hanya pada nama dan garap tabuhan bonang.

  19. Radiations cosmiques : danger dans l'Espace

    Science.gov (United States)

    Bonnet-Bidaud, J. M.; Dzitko, H.

    2000-06-01

    Au sol, l'atmosphere nous protege plus ou moins bien. Mais dans l'espace ou a bord des avions de ligne, l'homme est directement expose aux rayonnements cosmiques qui peuvent etre mortels. Un veritable frein a la presence humaine prolongee dans l'espace. Une menace que les agences spatiales prennent tres au serieux.

  20. Vast voer in zoogperiode belangrijker dan gedacht

    NARCIS (Netherlands)

    Peet-Schwering, van der C.M.C.; Binnendijk, G.P.; Troquet, L.M.P.

    2012-01-01

    Biggen die voor spenen vast voer opnemen (eters) groeien na spenen circa 50 gram per dag sneller dan biggen die tijdens de zoogperiode geen vast voer opnemen (niet-eters). Daarnaast groeien zwaardere biggen bij spenen circa 50 gram per dag sneller dan lichtere biggen bij spenen. Dit blijkt uit onder

  1. Fluidity and microstructure formation during flow of Al- SiC particle composites

    Science.gov (United States)

    Yarandi, F. M.; Rohatgi, P. K.; Ray, S.

    1993-06-01

    This article presents the results of casting and spiral fluidity in a Al-7 wt% Si alloy reinforced with 10,15, and 20 vol% SiC particles in permanent molds. The fluidity of the Al-SiC slurry increases linearly with temperature up to about 760 °C. Above this temperature, the casting fluidity of the Al-SiC particle slurry does not change significantly with an increase in temperature. In several cases, the fluidity decreased at temperatures above 760 °C. The fluidity of Al-SiC melts containing 9-μm SiC particles decreased with an increase in volume percentage of SiC up to 15 vol% (the range studied), presumably due to an increase in the viscosity of the melt with increasing volume percentage of dispersoid and changes in thermophysical properties of the composite. However, the fluidity of Al-20 vol% SiC of 14-μm particle size is higher than the fluidity of Al-15 vol% SiC 9-μm particles, indicating the role of particle size and surface area in de-creasing fluidity. Composite slurries travel farther in a channel of larger cross sections compared to channels of smaller cross sections under similar conditions. Casting fluidity increases linearly with an in-crease in cross section of the channel. A model has been proposed to calculate the values of fluidity of the composite as a function of particle volume percent, superheat, flow velocity of the melt, and the cross sec-tion of the flow channel. Experimental observations have been compared with the predictions of the model, and some deviations have been attributed to settling and segregation of SiC particles observed through microstructural examination.

  2. Fabrication of SiC Reinforced Zr0{sub 2} Composites via Polymeric Precursor Route

    Energy Technology Data Exchange (ETDEWEB)

    Mistarihi, Qusai M.; Hong, Soon Hyung; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    This indicates that as a result of the decomposition of the SMP-730 at temperatures less than or equal to 1500 .deg. C, amorphous SiC was formed. This study suggests that a higher compaction pressure followed by an intermediate decomposition temperature of the polymeric precursor and a higher sintering temperature are needed in order to fabricate interconnected SiC-ZrO{sub 2} composites. A. Ortona et al. fabricated ZrB2-SiC composites with SiC phase surrounding the grains of ZrB2 matrix through a polymeric precursor route by using Si and phenol. S. Li et al. measured the thermal conductivity of Al composites reinforced with a continuous phase SiC and SiC particles and found that the difference in the thermal conductivity measured at room temperature was about 70.2 W/m.K. To the best of authors' knowledge, no study has been performed about the fabrication of the connected SiC microstructure to improve the thermophysical properties of oxides. Zirconium dioxide (ZrO{sub 2}) is one of the potential candidates for use as a matrix for inert matrix fuels (IMF) due to its low neutron absorption cross section, chemical stability, and the compatibility with water. Irradiation and chemical stability testes performed on yttria stabilized zirconia (YSZ) and calcium stabilized zirconia (CSZ) have shown that they have a good irradiation and chemical stability. Despite the good irradiation and chemical stability, its low thermal conductivity is considered the main disadvantage of YSZ. Core loading with the YSZ IMF pellets experienced about a 100 K higher center line temperature than the limit specified for UO{sub 2}.

  3. On-chip temperature monitoring of a SiC current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, D.; Godignon, P.; Millan, J. [Centro Nacional de Microelectronica (CNM), Univ. Autonoma de Barcelona, Bellaterra (Spain); Planson, D.; Chante, J.P. [Centre de Genie Electrique de Lyon (CEGELY) INSA-LYON, UMR 5005 CNRS, Villeurbanne (France); Sarrus, F.; Palma, J.F. de [Ferraz Shawmut, Bonnet de Mure (France)

    2004-07-01

    High voltage and high current potentiality of SiC based devices has been proved, and various devices able to work at high temperature have been reported as well. Nevertheless, packaging is one of the main constrains for high temperature operation of these devices. Up to date, no specific power package has been reported for high temperature operation. Moreover, it is desirable to predict the SiC die temperature to avoid any related failure in order to improve the efficiency of the packaged SiC device. This paper deals with an integrated temperature sensor for SiC current limiting devices. The current limiter is based on a VJFET structure, which capability for dissipating high power density (140 kW/cm{sup 2}), in the limiting state, has been previously demonstrated. Carrier mobility dependence with temperature was extracted from cryogenic measurements. The temperature estimation is based on the measurement of the variation of the electrical resistance (caused by mobility variation) of the sensing device integrated with the current limiter. In this paper we first describe the temperature estimation methodology using various technological solution (from metallic resistor solution to the SiC integrated sensor). Then experimental temperature measurements using an integrated SiC sensor within a packaged current limiting devices will be presented. Electro-thermal measurements on the fabricated devices show that the current limiter is able to work at 205 C under steady state conditions (320 V), without degrading their electrical performances. Finally, perspectives in terms of integration and reliability will be proposed. (orig.)

  4. Proposal of a SiC disposal canister for very deep borehole disposal

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Heui-Joo; Lee, Minsoo; Lee, Jong-Youl; Kim, Kyungsu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper authors proposed a silicon carbide, SiC, disposal canister for the DBD concept in Korea. A. Kerber et al. first proposed the SiC canister for a geological disposal of HLW, CANDU or HTR spent nuclear fuels. SiC has some drawbacks in welding or manufacturing a large canister. Thus, we designed a double layered disposal canister consisting of a stainless steel outer layer and a SiC inner layer. KAERI has been interested in developing a very deep borehole disposal (DBD) of HLW generated from pyroprocessing of PWR spent nuclear fuel and supported the relevant R and D with very limited its own budget. KAERI team reviewed the DBD concept proposed by Sandia National Laboratories (SNL) and developed its own concept. The SNL concept was based on the steel disposal canister. The authors developed a new technology called cold spray coating method to manufacture a copper-cast iron disposal canister for a geological disposal of high level waste in Korea. With this method, 8 mm thin copper canister with 400 mm in diameter and 1200 mm in height was made. In general, they do not give any credit on the lifetime of a disposal canister in DBD concept unlike the geological disposal. In such case, the expensive copper canister should be replaced with another one. We designed a disposal canister using SiC for DBD. According to an experience in manufacturing a small size canister, the fabrication of a large-size one is a challenge. Also, welding of SiC canister is not easy. Several pathways are being paved to overcome it.

  5. Advantages and Limits of 4H-SIC Detectors for High- and Low-Flux Radiations

    Science.gov (United States)

    Sciuto, A.; Torrisi, L.; Cannavò, A.; Mazzillo, M.; Calcagno, L.

    2017-07-01

    Silicon carbide (SiC) detectors based on Schottky diodes were used to monitor low and high fluxes of photons and ions. An appropriate choice of the epilayer thickness and geometry of the surface Schottky contact allows the tailoring and optimizing the detector efficiency. SiC detectors with a continuous front electrode were employed to monitor alpha particles in a low-flux regime emitted by a radioactive source with high energy (>5.0 MeV) or generated in an ion implanter with sub-MeV energy. An energy resolution value of 0.5% was measured in the high energy range, while, at energy below 1.0 MeV, the resolution becomes 10%; these values are close to those measured with a traditional silicon detector. The same SiC devices were used in a high-flux regime to monitor high-energy ions, x-rays and electrons of the plasma generated by a high-intensity (1016 W/cm2) pulsed laser. Furthermore, SiC devices with an interdigit Schottky front electrode were proposed and studied to overcome the limits of the such SiC detectors in the detection of low-energy (˜1.0 keV) ions and photons of the plasmas generated by a low-intensity (1010 W/cm2) pulsed laser. SiC detectors are expected to be a powerful tool for the monitoring of radioactive sources and ion beams produced by accelerators, for a complete characterization of radiations emitted from laser-generated plasmas at high and low temperatures, and for dosimetry in a radioprotection field.

  6. PENGARUH KOMUNIKASI INTERN DAN KEPEMIMPINAN KEPALA SEKOLAH TERHADAP EFEKTIVITAS KERJA GURU DAN KARYAWAN SMP NEGERI 1 SURUH KABUPATEN SEMARANG

    Directory of Open Access Journals (Sweden)

    - Muhsin

    2006-12-01

    Full Text Available Permasalahan yang dikaji dalam penelitian ini adalah : 1 Adakah pengaruh komunikasi intern terhadap efektivitas kerja guru dan karyawan? 2 Adakah pengaruh kepemimpinan kepala sekolah terhadap efektivitas kerja guru dan karyawan? 3 Seberapa besar pengaruh komunikasi intern dan kepemimpinan kepala sekolah terhadap efektivitas kerja guru dan karyawan? Tujuan penelitian ini adalah : 1 untuk mengetahui ada dan besarnya pengaruh komunikasi intern terhadap efektivitas kerja guru dan karyawan. 2 Untuk mengetahui ada dan besarnya pengaruh Kepemimpinan kepala sekolah terhadap efektivitas kerja guru dan karyawan. 3.Untuk mengetahui ada dan besarnya pengaruh komunikasi intern dan kepemimpinan kepala sekolah terhadap efektivitas kerja guru dan karyawan. Populasi dalam penelitian ini adalah semua guru dan karyawan yang ada di SMP Negeri 1 Suruh kabupaten Semarang yang berjumlah 40 orang.. Metode pengumpulan data menggunakan angket dan dokumentasi. Analisis data menggunakan  program statistic SPSS. Hasil penelitian menunjukkan adanya pengaruh positif antara Komunikasi intern dan kepemimpinan kepala sekolah terhadap efektivitas kerja guru dan karyawan sebesar 68,7%. Uji pengaruh secara parsial menunjukkan bahwa seluruh variabel bebas  Komunikasi intern dan kepemimpinan kepala sekolah berpengaruh secara signifikan terhadap Efektivitas kerja  dengan besarnya pengaruh masing-masing adalah 32,61% Untuk Komunikasi intern dan 25,62% untuk kepemimpinan kepala sekolah. Kata Kunci : Komunikasi Intern. Kepemimpinan Kepala Sekolah, Efektivitas Kerja

  7. Penerapan Sistem Remunerasi dan Kinerja Pelayanan

    Directory of Open Access Journals (Sweden)

    Tri Wisesa Soetisna

    2015-08-01

    Full Text Available Remunerasi dapat memengaruhi motivasi pegawai sekaligus meningkatkan kinerjanya. Demikian halnya di rumah sakit sebagai institusi pelayanan kesehatan yang padat modal, sumber daya manusia serta padat ilmu dan teknologi. Penelitian ini bertujuan untuk menganalisis persepsi pegawai terhadap implementasi sistem remunerasi dan kinerja unit pelayanan bedah jantung dewasa (UPBJD di rumah sakit. Penelitian ini menggunakan pendekatan mixed methods (kuantitatif dan kualitatif. Desain penelitian kuantitatif adalah potong lintang menggunakan instrumen kuesioner self-assessment. Sedangkan desain penelitian kualitatif adalah deskriptif, dilakukan melalui focus group discussion dan telaah dokumen pada data berupa buku jadwal, buku registrasi, catatan keperawatan, dan rekam medis. Pengambilan data dilakukan pada tahun 2013 di salah satu rumah sakit di Jakarta. Responden/informan adalah staf medis fungsional, perawat, dan petugas administrasi berjumlah 29 orang. Data dianalisis secara univariat (metode kuantitatif, dan content analysis (metode kualitatif. Hasil penelitian menunjukkan bahwa sebagian besar staf medis fungsional dan perawat tidak puas (71,2% dengan beberapa hal dalam penerapan sistem remunerasi, seperti pada sistem penggajian dan penentuan grading. Terlihat kinerja unit pelayanan bedah jantung dewasa mengalami kenaikan setiap tahun sebelum dan setelah penerapan sistem remunerasi. Diharapkan agar rumah sakit ini dapat memperbaiki sistem remunerasi yang sesuai ketentuan kebijakan dan menyusun formulasi insentif dan bonus yang lebih sesuai dengan kondisi saat ini serta perlu dilakukan sosialisasi yang tepat dan evaluasi secara berkala. Implementation of Remuneration System and Service Performance Remuneration can influence worker`s motivation, and improve their performance. Likewise in hospital as capital-intensive, human resources-intensive as well as knowledge and technology-intensive health care institution. This study aimed to analyze employee

  8. Surface finish effects and the strength-grain size relation in SiC

    Science.gov (United States)

    Cranmer, D. C.; Tressler, R. E.; Bradt, R. C.

    1977-01-01

    The effect of surface finish on the strength-grain size relation was investigated for dense hot-pressed SiC. Failure initiated predominantly via the propagation of extrinsic machining-induced flaws for the range of grain sizes and machining grit sizes studied. These results are consistent with the region of large-grain-size flaw control as delineated by Prochazka and Charles. The severity of machining-induced flaws, relative to the machining grit size, decreased with increasing machining grit size and decreasing SiC grain size.

  9. A Novel DBC Layout for Current Imbalance Mitigation in SiC MOSFET Multichip Power Modules

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig; Beczkowski, Szymon

    2016-01-01

    This paper proposes a novel Direct Bonded Copper (DBC) layout for mitigating the current imbalance among the paralleled SiC MOSFET dies in multichip power modules. Compared to the traditional layout, the proposed DBC layout significantly reduces the circuit mismatch and current coupling effect......, which consequently improves the current sharing among the paralleled SiC MOSFET dies in power module. Mathematic analysis and circuit model of the DBC layout are presented to elaborate on the superior features of the proposed DBC layout. Simulation and experimental results further verify the theoretical...

  10. A Novel DBC Layout for Current Imbalance Mitigation in SiC MOSFET Multichip Power Modules

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig; Beczkowski, Szymon

    2016-01-01

    This letter proposes a novel direct bonded copper (DBC) layout for mitigating the current imbalance among the paralleled SiC MOSFET dies in multichip power modules. Compared to the traditional layout, the proposed DBC layout significantly reduces the circuit mismatch and current coupling effect......, which consequently improves the current sharing among the paralleled SiC MOSFET dies in power module. Mathematic analysis and circuit model of the DBC layout are presented to elaborate the superior features of the proposed DBC layout. Simulation and experimental results further verify the theoretical...

  11. La théorie des industries culturelles (et informationnelles, composante des SIC

    Directory of Open Access Journals (Sweden)

    Bernard Miège

    2012-09-01

    Full Text Available Inaugurer le Cahier central de la Revue des SIC est certes une forme de reconnaissance, mais cela comporte des obligations, au premier rang desquelles la nécessité d’intéresser des lecteurs a priori pas immédiatement concernés par la thématique.Si la théorie des industries culturelles est devenue progressivement une approche marquante des SIC, en France, en Europe et plus largement encore (avec des dénominations variables et des modalités spécifiques, ce n’est en effet ni en le proclamant ha...

  12. Quasi-Freestanding multilayer graphene films on the carbon face of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, D. A.; Hwang, C. G.; Fedorov, A. V.; Lanzara, A.

    2010-06-30

    The electronic band structure of as-grown and doped graphene grown on the carbon face of SiC is studied by high-resolution angle-resolved photoemission spectroscopy, where we observe both rotations between adjacent layers and AB-stacking. The band structure of quasi-freestanding AB-bilayers is directly compared with bilayer graphene grown on the Si-face of SiC to study the impact of the substrate on the electronic properties of epitaxial graphene. Our results show that the C-face films are nearly freestanding from an electronic point of view, due to the rotations between graphene layers.

  13. drs (Distantly Related sic) Gene Polymorphisms among emm12-Type Streptococcus pyogenes Isolates

    Science.gov (United States)

    Brandt, Claudia M.; Haase, Gerhard; Spellerberg, Barbara; Holland, Regina; Lütticken, Rudolf

    2003-01-01

    Twenty-eight emm12-type Streptococcus pyogenes isolates from patients with invasive and noninvasive infections or from asymptomatic carriers were genetically typed. Sequencing of drs (distantly related sic [streptococcal inhibitor of complement]) genes identified two novel alleles and revealed a polymorphism for drs similar to that of sic. No association was observed between the five different drs alleles and the five restriction patterns of the vir regulon for the isolates studied. These data suggest that drs sequencing may be useful for further differentiation of S. pyogenes isolates with emm12 and identical vir regulon restriction patterns. PMID:12682191

  14. High efficiency battery converter with SiC devices for residential PV systems

    DEFF Research Database (Denmark)

    Pham, Cam; Teodorescu, Remus; Kerekes, Tamas

    2013-01-01

    The demand for high efficiency and higher power density is a challenge for Si-based semiconductors due to the physical characteristics of material. These can be overcome by employing wide-band-gap materials like SiC. This paper compares a second generator SiC MOSFETs against a normally-on Trench ...... JFETs and theirs performances in a high efficiency battery converter for residential photovoltaic systems. The prototypes are 3 kW converters with more than 98% efficiency and high simplicity and power density....

  15. PSpice Modeling Platform for SiC Power MOSFET Modules with Extensive Experimental Validation

    DEFF Research Database (Denmark)

    Ceccarelli, Lorenzo; Iannuzzo, Francesco; Nawaz, Muhammad

    2016-01-01

    The aim of this work is to present a PSpice implementation for a well-established and compact physics-based SiC MOSFET model, including a fast, experimental-based parameter extraction procedure in a MATLAB GUI environment. The model, originally meant for single-die devices, has been used to simul......The aim of this work is to present a PSpice implementation for a well-established and compact physics-based SiC MOSFET model, including a fast, experimental-based parameter extraction procedure in a MATLAB GUI environment. The model, originally meant for single-die devices, has been used...

  16. Preparation of patterned SiC and SiCN microstructures

    Institute of Scientific and Technical Information of China (English)

    WANG; Hao; SUNG; In-kyung; LI; Xiaodong; KIM; Dong-pyo

    2006-01-01

    Patterned SiC and SiCN microstructures were successfully fabricated on the silicon substrates by using polydimethylsiloxane (PDMS) elastometric stamp as template, polycarbosilane (PCS) and polysilazane (PSZ) as preceramic polymers. The preparing process was followed by precursor infiltration, the curing of the precursor, demolding of the template and pyrolysis of the cured preceramic polymer pattern. It shows that the dimensions of the ceramic patterns can be tailored by using the PDMS molds with different dimensions. The produced ceramic microstructures can be potentially applied in high temperature and high pressure environments due to the advanced properties of the SiC and SiCN ceramics.

  17. Quasi-Freestanding multilayer graphene films on the carbon face of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, D. A.; Hwang, C. G.; Fedorov, A. V.; Lanzara, A.

    2010-06-30

    The electronic band structure of as-grown and doped graphene grown on the carbon face of SiC is studied by high-resolution angle-resolved photoemission spectroscopy, where we observe both rotations between adjacent layers and AB-stacking. The band structure of quasi-freestanding AB-bilayers is directly compared with bilayer graphene grown on the Si-face of SiC to study the impact of the substrate on the electronic properties of epitaxial graphene. Our results show that the C-face films are nearly freestanding from an electronic point of view, due to the rotations between graphene layers.

  18. Fabrication of broadband antireflective sub-wavelength structures on fluorescent SiC

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicus, V.; Kaiser, M.

    2013-01-01

    Surface nanocones on 6H-SiC have been developed and demonstrated as an effective method of enhancing the light extraction efficiency from fluorescent SiC layers. The surface reflectance, measured from the opposite direction of light emission, over a broad bandwidth range is significantly suppress...... from 20.5% to 1.0 % after introducing the sub-wavelength structures. An omnidirectional light harvesting enhancement (>91%), is also achieved which promotes fluorescent SiC as a good candidate of wavelength converter for white light-emitting diodes....

  19. Bipolar integrated circuits in SiC for extreme environment operation

    Science.gov (United States)

    Zetterling, Carl-Mikael; Hallén, Anders; Hedayati, Raheleh; Kargarrazi, Saleh; Lanni, Luigia; Malm, B. Gunnar; Mardani, Shabnam; Norström, Hans; Rusu, Ana; Saveda Suvanam, Sethu; Tian, Ye; Östling, Mikael

    2017-03-01

    Silicon carbide (SiC) integrated circuits have been suggested for extreme environment operation. The challenge of a new technology is to develop process flow, circuit models and circuit designs for a wide temperature range. A bipolar technology was chosen to avoid the gate dielectric weakness and low mobility drawback of SiC MOSFETs. Higher operation temperatures and better radiation hardness have been demonstrated for bipolar integrated circuits. Both digital and analog circuits have been demonstrated in the range from room temperature to 500 °C. Future steps are to demonstrate some mixed signal circuits of greater complexity. There are remaining challenges in contacting, metallization, packaging and reliability.

  20. Role of Defects in Swelling and Creep of Irradiated SiC

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States); Voyles, Paul [Univ. of Wisconsin, Madison, WI (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-16

    Silicon carbide is a promising cladding material because of its high strength and relatively good corrosion resistance. However, SiC is brittle and therefore SiC-based components need to be carefully designed to avoid cracking and failure by fracture. In design of SiC-based composites for nuclear reactor applications it is essential to take into account how mechanical properties are affected by radiation and temperature, or in other words, what strains and stresses develop in this material due to environmental conditions. While thermal strains in SiC can be predicted using classical theories, radiation-induced strains are much less understood. In particular, it is critical to correctly account for radiation swelling and radiation creep, which contribute significantly to dimensional instability of SiC under radiation. Swelling typically increases logarithmically with radiation dose and saturates at relatively low doses (damage levels of a few dpa). Consequently, swelling-induced stresses are likely to develop within a few months of operation of a reactor. Radiation-induced volume swelling in SiC can be as high as 2%, which is significantly higher than the cracking strain of 0.1% in SiC. Swelling-induced strains will lead to enormous stresses and fracture, unless these stresses can be relaxed via some other mechanism. An effective way to achieve stress relaxation is via radiation creep. Although it has been hypothesized that both radiation swelling and radiation creep are driven by formation of defect clusters, existing models for swelling and creep in SiC are limited by the lack of understanding of specific defects that form due to radiation in the range of temperatures relevant to fuel cladding in light water reactors (LWRs) (<1000°C). For example, defects that can be detected with traditional transmission electron microscopy (TEM) techniques account only for 10-45% of the swelling measured in irradiated SiC. Here, we have undertaken an integrated experimental and

  1. Producing composite materials based on ZrB2, ZrB2-SiC

    Science.gov (United States)

    Mirovoi, Yu A.; Burlachenko, A. G.; Buyakova, S. P.; Sevostiyanova, I. N.; Kulkov, S. N.

    2016-11-01

    The effect of mechanical treatment by planetary ball milling on the properties of hot pressed ZrB2 - SiC ceramics was studied. It has been shown that material densification after mechanical treatment is finished at initial stages of sintering process. Addition of SiC causes a substantial increase in density of the sample to 99% of the theoretical powder containing 20% of silicon carbide, in comparison with samples ZrB2 density not exceeding 76%. It has been shown that all defects which were accumulated during mechanical treatment anneal in hot pressure process and there are no any changes of CDD values in sintered ceramics.

  2. Ab initio quasiparticle energies in 2H, 4H, and 6H SiC

    Science.gov (United States)

    Ummels, R. T. M.; Bobbert, P. A.; van Haeringen, W.

    1998-09-01

    Ab initio quasiparticle energies are calculated for the 2H, 4H, and 6H polytypes of SiC within the GW approximation for the self-energy. The starting point is a calculation within the pseudopotential local-density approximation framework. The calculated fundamental gaps of 3.15, 3.35, and 3.24 eV for 2H, 4H, and 6H SiC, respectively, show very good agreement with experimental data. The energy dependence of the screened interaction is modeled by a plasmon pole model from which the plasmon band structures are obtained.

  3. 1700 V SiC Schottky diodes scaled to 25 A

    Energy Technology Data Exchange (ETDEWEB)

    Peters, D.; Dohnke, K.O.; Hecht, C.; Stephani, D. [SiCED Electronics Development Ltd., Erlangen (Germany)

    2001-07-01

    This paper reports on a study of SiC Schottky diodes focused on high current rating and high blocking voltage: 25 A / 1200 V and 1700V, resp. With an active area of 10 mm{sup 2} we successfully explored new ground for SiC devices. The device concept, fabrication process, yield aspects and measured results of static and dynamic characteristics as well as the temperature behavior are described. The reverse currents are very low (<500 {mu}A) even at 125 C and their temperature dependence is lower than expected by thermionic emission since tunneling mechanisms through the Schottky barrier rule the current transport at high blocking voltages. (orig.)

  4. Nanomechanical properties of SiC films grown from C{sub 60} precursors using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Morse, K. [Colorado School of Mines, Golden, CO (United States); Balooch, M.; Hamza, A.V.; Belak, J. [Lawrence Livermore National Lab., CA (United States)

    1994-12-01

    The mechanical properties of SiC films grown via C{sub 60} precursors were determined using atomic force microscopy (AFM). Conventional silicon nitride and modified diamond cantilever AFM tips were employed to determine the film hardness, friction coefficient, and elastic modulus. The hardness is found to be between 26 and 40 GPa by nanoindentation of the film with the diamond tip. The friction coefficient for the silicon nitride tip on the SiC film is about one third that for silicon nitride sliding on a silicon substrate. By combining nanoindentation and AFM measurements an elastic modulus of {approximately}300 GPa is estimated for these SiC films. In order to better understand the atomic scale mechanisms that determine the hardness and friction of SiC, we simulated the molecular dynamics of a diamond indenting a crystalline SiC substrate.

  5. PREPARATION OF LEAD-ACID BATTERY USING ELECTROPLATED RETICULATED SiC AS THE POSITIVE CURRENT COLLECTOR

    Institute of Scientific and Technical Information of China (English)

    Z.M. Zou; X.M. Cao; C. Tian; J.S. Zhang

    2005-01-01

    The possibility of using Pb-electroplated reticulated SiC as the positive current collector for lead-acid batteries was investigated. Reticulated SiC with two aperture sizes (3 and 2mm) were tested as the substrate of positive electrode. It was found that the reticulated SiC has an excellent corrosion resistance in H2SO4 solution, and the Pb layer electroplated on reticulated SiC showed analogous electrochemical behavior to metal Ph. Preliminary test of the battery performance indicated that the utilization efficiency of the positive active mass of new designed batteries are improved compared with the conventional batteries. The improvement could be ascribed to the high specific surface area of the reticulated structured positive current collector, which was further supported by the even better performance of the battery made from a smaller aperture size (2mm) reticulated SiC as the substrate of the positive electrode.

  6. Poétique de l’invective dans les Poèmes aristophanesques de Laurent Tailhade

    Directory of Open Access Journals (Sweden)

    Laurent Robert

    2012-04-01

    Full Text Available Parmi l’abondant corpus traité par Marc Angenot dans La Parole pamphlétaire, les ouvrages de Laurent Tailhade Au Pays du mufle et À travers les Grouins [sic] constituent les seuls recueils poétiques. L’essayiste y voit une illustration du genre de la satire poétique, revivifié dès la fin du xviiie siècle avec les Iambes d’André Chénier, puis au xixe notamment par Auguste Barbier et Victor Hugo. Tailhade pourrait ainsi, superficiellement, être considéré comme le poète satiriste de la Troisième...

  7. Solar cells and thin film LED using amorphous SiC. Amorphous SiC wo mochiita taiyou denchi oyobi usumaku LED

    Energy Technology Data Exchange (ETDEWEB)

    Hamakawa, Y. (Osaka Univ., Osaka (Japan). Faculty of Engineering Science)

    1990-03-25

    This paper introduced the photoelectric properties of amorphous SiC (a-SiC), application to highly efficient solar cells, application to wide area emitting elements such as LED (light emitting diode) and application to OEIC (optoelectronic integrated circuit) which is expected in near future. The light sensitizing effect in which photoconductivity of a-SiC:H film increases 2-3 figures by B dopping, was found. Flexible and wide area thin film LED has been able to manufacture by this discovery. In addition, highly efficient conversion rate has been able to get by the technical development such as solar cells made of a-SiC/ a-Si hetrojunction. Further, wide area sollar cells has been able to manufacture on any substrate by the development of TFLED (thin film light emitting diode). The application of TFLED made of SiC to OEIC is also investigated. 18 refs., 15 figs., 2 tabs.

  8. Guard-ring termination for high-voltage SiC Schottky barrier diodes; Guard ring shutan kozo wo sonaeta kotaiatsu SiC Schottky barrier diode

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Urushidani, T.; Seki, Y. [Fuji Electric Corporate Research and Development, Ltd., Kanagawa (Japan)

    1996-03-10

    Silicon carbide (SiC) has been attracting attention as a material for power devices, and has already demonstrated its favorable characteristics in Schottky barrier diodes (SBD) with gold or platinum. However, few researchers have discussed the device terminal structures, and the authors propose a simple, efficient guard-ring terminal structure. The SBD of SiC is prepared, with Al/Ti as the Schottky metals. The Al/Ti electrode forms a Schottky barrier with the n-type drift region, and an ohmic contact with the p-type region, i.e., guard-ring region. Resistance of this structure to voltage is determined by that of the mesa section of the p-n junction, and the mesa structure is formed by selective oxidation. The SBD shows a break-down voltage of 550V, which is roughly twice as high as that of an SBD having no guard-ring structure. 7 refs., 3 figs.

  9. KARAKTERISASI SIMPLISIA DAN EKSTRAK DAUN STROBILANTHUS CRISPUS

    Directory of Open Access Journals (Sweden)

    Ani Isnawati

    2012-10-01

    Full Text Available Khasiat obat tradisional disebabkan oleh adanya senyawa kimia yang  dikandungnya. Bahan baku obat dari hasil pertanian atau kumpulan tumbuhan liar tentunya kandungan kimianya tidak dapat dijamin selalu konstan (ajeg karena adanya variabel bibit, tempat tumbuh, iklim, kondisi (umur dan cara panen. Kandungan senyawa kimia yang bertanggung jawab terhadap respon biologis harus mempunyai spesifikasi kimia, yaitu informasi  komposisi (jenis dan kadar. 0leh karena itu penetapan karakterisasi suatu simplisia dan ekstrak perlu dilakukan guna menjamin bahwa bahan suatu produk obat tradisional dapat diketahui mutunya. Karakterisasi dilakukan terhadap Tanaman Strobilanthus crispus (BL, yaitu simplisia bagian daun dan ekstrak 50% tanaman tersebut. Karakterisasi simplisa meliputi : penetapan kadar abu, kadar abu larut air, kadar abu tidak larut asam, kadar sari larut air, kadar sari larut asam, dan kadar air secar·a destilasi. Cara penetapan diatas dilakukan sesuai prosedur yang Ielah ditetapkan MMI, 1979. Sedangkan karakterisasi ekstrak mencakup : karakterisasi non spesifik yang meliputi penetapan bobot  jenis, kadar air, kadar sisa pelarut, kadar abu dan karakterisasi spesifik yang mencakup  pemeriksaan·senyawa yang terlarut dalam pelarut air dan etanol, pola kromatografi dengan cara KLT-densitometri, pemeriksaan golongan kimia ekstrak dan penetapan kadar zat kimia. Hasil penetapan karakterisasi simplisia menunjukkan spesifikasi tidak sesuai dengan yang dipersyaratkan MMI, hanya penetapan sari larut etanol yang memenuhi persyaratan. Penetapan karakterisasi ekstrak etanol 50% menunjukkan tidak terdapat etanol dalam ekstrak, kadar air 13,3 %; bobot jenis 1,262%, senyawa terlarut dalam pelarut air 95,06%, senyawa terlarut dalam pelarut etanol 18,69 % dan kadar flavonoid  17,59 % serta  profil  kromatogram komponen utama fraksi heksan, Khloroform dan etanol.

  10. Testing of porous SiC with dense coating under relevant conditions for Flow Channel Insert application

    Energy Technology Data Exchange (ETDEWEB)

    Ordás, N., E-mail: nordas@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Bereciartu, A.; García-Rosales, C. [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Moroño, A.; Malo, M.; Hodgson, E.R. [CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Abellà, J.; Colominas, S. [Institut Químic de Sarrià, University Ramon Llull, Via Augusta 390, 08017 Barcelona (Spain); Sedano, L. [CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)

    2014-10-15

    Highlights: • Porous SiC coated by CVD with a dense coating was developed for Flow Channel Inserts (FCI) in dual-coolant blanket concept. • Porous SiC was obtained following the sacrificial template technique, using Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} as sintering additives. • Flexural strength, thermal and electrical conductivity, and microstructure of uncoated and coated porous SiC are presented. • Adhesion of coating to porous SiC and its corrosion behavior under Pb-17.5Li at 700 °C are shown. - Abstract: Thermally and electrically insulating porous SiC ceramics are attractive candidates for Flow Channel Inserts (FCI) in dual-coolant blanket concepts thanks to its relatively inexpensive manufacturing route. To prevent tritium permeation and corrosion by Pb-15.7 a dense coating has to be applied on the porous SiC. Despite not having structural function, FCI must exhibit sufficient mechanical strength to withstand strong thermal gradients and thermo-electrical stresses during operation. This work summarizes the results on the development of coated porous SiC for FCI. Porous SiC was obtained following the sacrificial template technique, using Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} as sintering additives and a carbonaceous phase as pore former. Sintering was performed in inert gas at 1850–1950 °C during 15 min to 3 h, followed by oxidation at 650 °C to eliminate the carbonaceous phase. The most promising bulk materials were coated with a ∼30 μm thick dense SiC by CVD. Results on porosity, bending tests, thermal and electrical conductivity are presented. The microstructure of the coating, its adhesion to the porous SiC and its corrosion behavior under Pb-17.5Li are also shown.

  11. Nickel matrix composite electro coatings containing high concentration of incorporated Sic; Rivestimenti lettrolitici compositi a matrice di nichel, a elevata concentrazione di particelli incorporate di SiC

    Energy Technology Data Exchange (ETDEWEB)

    Psarrou, S.; Spyrellis, N. [National Technical University of Athens (Greece)

    1999-08-01

    This paper gives the results of the study on the preparation of nickel matrix composite electro coatings, containing incorporate silicon carbide (SiC) microparticles under either direct current (D.C.) or pulse current (P.C.) conditions. It is proved that the applicability of pulse plating techniques modifies significantly the control of metal electro crystallization procedure. Under specific preparation conditions, the application of pulse current results to Ni/SiC composite coatings with better surface morphology, higher incorporation percentages and more uniform distribution of the insert SiC microparticles in the metallic matrix than the direct current technique. Pulse electrolysis is thus a powerful mean of perturbing the absorption-desorption phenomena occurring at the nickel/electrolyte interface and hence influences the incorporation procedure to a significant grade. [Italian] Questo articolo fornisce i risultati di uno studio condotto sulla preparazione di elettrodepositi compositi a matrice di nichel per incorporazione di microparticelle di carburo di silicio (SiC), ottenuti sia in condizione di corrente diretta (C.D.) sia di corrente a impulsi (C.P.). E' ormai appurato che l'applicazione della tecnica ad impulsi modifica in modo rilevante il controllo della fase di elettrocristallizazione del metallo. La corrente ad impulsi, in particolare e specifiche condizioni operative, porta all'ottenimento di rivestimenti compositi Ni/SiC con migliorata morfologia superficiale, inoltre la percentuale di particelle incorporate e' piu' elevata e la distribuzione di micro particelle inerti di SiC nella matrice metallica e' piu' uniforme rispetto ai codepositi ottenuti con la tecnica a corrente diretta. L'elettrolisi a impulsi e' quindi uno strumento efficace per perturbare i fenomeni di absorbimento-desorbimento che avvengono all'interfaccia nichel/elettrolita e influenza significativamente il meccanismo di

  12. TUGAS DAN WEWENANG PUSAT PELAPORAN DAN ANALISIS TRANSAKSI KEUANGAN (PPATK DALAM PEMBERANTASAN TINDAK PIDANA PENCUCIAN UANG

    Directory of Open Access Journals (Sweden)

    Johari Johari

    2014-03-01

    Full Text Available Tugas dan wewenang Pusat Pelaporan dan Analisis Transaksi Keuangan (PPATK terdapat di dalam Pasal 26 dan Pasal 27 Undang-Undang No. 25 Tahun 2003 tentang Tindak Pencucian Uang. Berdasarkan ketentuan tersebut, tugas dan wewenang PPATK tersebut bertujuan untuk mendeteksi terjadinya tindak pidana pencucian uang, dan membantu penegakan hukum yang berkaitan dengan pencucian uang, termasuk tindak pidana asal yang melahirkannya (predicate offences. Namun, Peranan PPATK akan berjalan secara efektif apabila aparat penegak hukum seperti Kepolisian, Kejaksaan, Pengadilan, Bea dan Cukai, para regulator seperti Bank Indonesia, Departemen Keuangan, Badan Pengawas Pasar Modal serta Penyedia Jasa Keuangan, industri perbankan, asuransi, perusahaan pembiayaan, dana pensiun, perusahaan efek, pengelola reksadana, media massa, masyarakat bekerjasama secara terorganisir dan terpadu dalam pemberantasan tindak pencucian uang di Indonesia. Dengan kewenangan yang dimilikinya, PPATK dapat mengejar hasil dari kejahatan, apabila hasil kejahatan tersebut dapat dikejar dan disita maka negara dengan sendirinya akan mengurangi tindak kejahatan itu sendiri. Kata kunci : Pencucian uang, tindak pidana pencucian uang (money laundering, kejahatan terorganisir, dan Pusat Pelaporan dan Analisis Transaksi Keuangan (PPATK.

  13. Peran Mitra Strategis dan Agen Perubahan dalam Manajemen Talenta dan Kinerja Manajer

    Directory of Open Access Journals (Sweden)

    Ida Ketut Kusumawijaya

    2014-06-01

    Full Text Available Abstract  The purposes of the study are to analyze: (1 characteristic of strategic partner and change agent roles, talent management and managers performance, (2 influence of strategic partner and change agent roles to talent management and its impact to managers performance. Four hundred hotel managers in Bali were participated in this study by using proportional random sampling. Data were analyzed using descriptive analysis and SEM. The result shows that: (1 strategic partner and change agent role, talent management and managers performance are in enough category, (2 positive and significant effect between strategic partner and change agent roles to talent management and its impact to managers performance. Keywords:Strategic Partner Role, Change Agent Role, Talent Management, Managers Performance.AbstrakTujuan penelitian ini adalah untuk menganalisis: (1 karakteristik dari mitra strategis dan peran agen perubahan, manajemen bakat dan kinerja manajer, (2 pengaruh mitra strategis dan peran agen perubahan untuk manajemen bakat dan dampaknya terhadap kinerja manajer. Sebanyak empat ratus manajer hotel di Bali berpartisipasi dalam penelitian ini dengan menggunakan proporsional random sampling. Data dianalisis menggunakan analisis deskriptif dan SEM. Hasil penelitian menunjukkan bahwa: (1 mitra strategis dan peran agen perubahan, manajemen bakat dan kinerja manajer termasuk dalam kategori cukup, (2 pengaruh positif dan signifikan antara mitra strategis dan peran agen perubahan untuk manajemen bakat dan dampaknya terhadap kinerja manajer.Keywords: Peran Mitra Strategis, Peran Agen Perubahan, Manajemen Talenta, kinerja Manajer.

  14. SiC Multi-Chip Power Modules as Power-System Building Blocks

    Science.gov (United States)

    Lostetter, Alexander; Franks, Steven

    2007-01-01

    The term "SiC MCPMs" (wherein "MCPM" signifies "multi-chip power module") denotes electronic power-supply modules containing multiple silicon carbide power devices and silicon-on-insulator (SOI) control integrated-circuit chips. SiC MCPMs are being developed as building blocks of advanced expandable, reconfigurable, fault-tolerant power-supply systems. Exploiting the ability of SiC semiconductor devices to operate at temperatures, breakdown voltages, and current densities significantly greater than those of conventional Si devices, the designs of SiC MCPMs and of systems comprising multiple SiC MCPMs are expected to afford a greater degree of miniaturization through stacking of modules with reduced requirements for heat sinking. Moreover, the higher-temperature capabilities of SiC MCPMs could enable operation in environments hotter than Si-based power systems can withstand. The stacked SiC MCPMs in a given system can be electrically connected in series, parallel, or a series/parallel combination to increase the overall power-handling capability of the system. In addition to power connections, the modules have communication connections. The SOI controllers in the modules communicate with each other as nodes of a decentralized control network, in which no single controller exerts overall command of the system. Control functions effected via the network include synchronization of switching of power devices and rapid reconfiguration of power connections to enable the power system to continue to supply power to a load in the event of failure of one of the modules. In addition to serving as building blocks of reliable power-supply systems, SiC MCPMs could be augmented with external control circuitry to make them perform additional power-handling functions as needed for specific applications: typical functions could include regulating voltages, storing energy, and driving motors. Because identical SiC MCPM building blocks could be utilized in a variety of ways, the cost

  15. POLA KONSUMSI PANGAN DAN ASUPAN ENERGI DAN ZAT GIZI ANAK STUNTING DAN TIDAK STUNTING 0—23 BULAN

    Directory of Open Access Journals (Sweden)

    Aslis Wirda Hayati

    2013-10-01

    menganalisis pola konsumsi pangan dan asupan energi dan gizi anak stunting dan tidak stunting 0—23 bulan menggunakan data Riskesdas 2010. Sub-set data Riskesdas 2010 diperoleh dalam bentuk e-files. Dari 6 634 data anak baduta dalam e-files Riskesdas 2010, sejumlah 3 539 data anak dikeluarkankarena data tidak lengkap, pencilan, konsumsi pangan saat kondisi tidak biasa. Status gizi diolah menggunakan WHO AntroPlus 2007, pengolahan data lainnya menggunakan program Microsoft Excel 2007 dan SPSS for windows. Uji beda pola konsumsi pangan menerapkan Mann-Whitney U test. Pola konsumsi pangan dan asupan energi dan zat gizi yang diukur berupa jumlah jenis konsumsi pangan, jumlah kelompok konsumsi pangan, frekuensi konsumsi pangan, tingkat kecukupan zat gizi, mutu gizi asupan pangan, dan densitas asupan zat gizi. Hasil kajian menunjukkan pola konsumsi pangan dan asupan energi dan zat gizi anak stunting dan tidak stunting 0—23 bulan berbeda menurut kelompok umur; semakin bertambah umur semakin meningkat perbedaannya. Pada anak 0—5 bulan tidak ada perbedaan pola konsumsi pangan dan asupan energi dan gizi anak stunting dan tidak stunting; sebaliknya pada anak 6—11 dan 12—23 bulan. Pada anak 6—11 bulan, rata-rata tingkat kecukupan protein anak stunting dan tidak stunting berbeda, demikian pula densitas asupan protein.Pada anak 12—23 bulan, tidak hanya rata-rata tingkat kecukupan protein dan densitas asupan protein, tetapi rata-rata tingkat kecukupan energi, tingkat kecukupan kalsium dan densitas asupan kalsium, tingkat kecukupan fosfor, tingkat kecukupan vitamin A, tingkat kecukupan vitamin C, mutu gizi makanan, dan bahkan jenis pangan juga berbeda. Implikasi untuk Indonesia yaitu perlu dilakukan penelitian efikasi intervensi zat gizi tersebut untuk pencapaian pertumbuhan linier optimal anak.Kata kunci: anak usia 0—23 bulan, pola konsumsi pangan, stunting

  16. TiC/Ti3SiC2复合材料的制备及其性能研究%Preparation and properties of TiC/Ti3SiC2 composites

    Institute of Scientific and Technical Information of China (English)

    贾换; 尹洪峰; 袁蝴蝶; 杨祎诺

    2012-01-01

    以粉末Ti,Si,TiC和炭黑为原料,采用反应热压烧结法制备TiC/Ti3SiC2复合材料.借助XRD和SEM研究TiC含量对TiC/Ti3SiC2复合材料相组成、显微结构及力学特性的影响.结果表明:通过热压烧结可以得到致密度较高的TiC/Ti3SiC2复合材料;引入TiC可以促进Ti3SiC2的生成,当引入TiC的质量分数达30%,TiC/Ti3SiC2复合材料的弯曲强度和断裂韧性分别为406.9 MPa,3.7 MPa·m1/2;复合材料中Ti3SiC2相以穿晶断裂为主,TiC晶粒易产生拔出.%TiC/Ti3SiC2 composites were fabricated by reactive hot pressing sintering method using the mixture powder of Ti, Si, C and TiC as raw material. The effect of TiC content on phase composition, microstructure and mechanical properties of TiC/Ti3SiC2 composites was investigated by X-ray diffraction and scanning electron microscopy. The results demonstrate that dense TiC/ Ti3SiC2 composites can be obtained by hot pressing. The addition of TiC into composites can enhance the formation of TisSiC2. When the additional content of TiC reaches 30% (mass fraction) , the flexural strength and fracture toughness of TiC/Ti3SiC2 composite are 406.9 MPa and 3.7 MPa·m-2, respectively. Ti3SiC2 phase displays intergranular fracture and TiC grain pulls out from Ti3SiC2 matrix when TiC/Ti3SiC2 composite fractures.

  17. KONSTRUKSI DETERMINAN DALAM FRASA NOMINA BAHASA PRANCIS DAN BAHASA INDONESIA

    Directory of Open Access Journals (Sweden)

    Roswita Lumban Tobing

    2012-06-01

    Full Text Available Artikel ini bertujuan untuk memaparkan konstruksi determinan pada frasa nomina bahasa Perancis dan bahasa Indonesia. Analisis yang digunakan adalah analisis kontrastif. Hasil analisis menunjukkan bahwa nomina bahasa Perancis memiliki jenis kelamin (maskulin/feminin dan jumlah (tunggal/jamak. Gender dan jumlah dalam bahasa Prancis memiliki aturan konkordansi yang dapat memengaruhi bentuk dan makna nomina. Dalam bahasa Indonesia, meskipun nomina memiliki konsep gender tunggal dan jamak, jenis dan jumlah dalam bahasa Indonesia tidak muncul secara eksplisit. Bentuk ini hanya ditandai dengan karakteristik semantik tertentu yang dapat menunjukkan jenis kelamin, bentuk tunggal, dan bentuk jamak.

  18. Effect of SiC and GR Reinforcement Particles on the Structure and Functional Properties of Composite Casting E43 MMC Reinforced with SiC Particles

    Directory of Open Access Journals (Sweden)

    Boczkal S.

    2016-03-01

    Full Text Available The aim of the study was to describe the structure of composites based on the AlSi7Mg2Sr0.03 alloy matrix reinforced with SiC particles added in an amount of 10% and with a mixture of SiC and GR particles added in a total amount of 20%. Studies of the composite structure, were carried out by scanning electron microscopy (SEM. Based on the results of chemical analysis in microregions, an increased content of elements such as Mg, O and Si and of the precipitates was observed at the interface. In many places in the examined sample, GR particles formed partly disintegrated conglomerates with well developed boundaries. The effect of the content of particles of the reinforcing phase on the functional properties of the composite was investigated during studies of abrasion. The lowest mass loss of 5,33mg was obtained for the AlSi7Mg2Sr0.03 alloy reinforced with 10% SiC particles.

  19. Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC

    Directory of Open Access Journals (Sweden)

    Chariya Virojanadara

    2013-01-01

    Full Text Available Graphene grown on C-face SiC substrates using two procedures, high and low growth temperature and different ambients, was investigated using Low Energy Electron Microscopy (LEEM, X-ray Photo Electron Electron Microscopy (XPEEM, selected area Low Energy Electron Diffraction (μ-LEED and selected area Photo Electron Spectroscopy (μ-PES. Both types of samples showed formation of μm-sized grains of graphene. The sharp (1 × 1 μ-LEED pattern and six Dirac cones observed in constant energy photoelectron angular distribution patterns from a grain showed that adjacent layers are not rotated relative to each other, but that adjacent grains in general have different azimuthal orientations. Diffraction spots from the SiC substrate appeared in μ-LEED patterns collected at higher energies, showing that the rotation angle between graphene and SiC varied. C 1s spectra collected did not show any hint of a carbon interface layer. A hydrogen treatment applied was found to have a detrimental effect on the graphene quality for both types of samples, since the graphene domain/grain size was drastically reduced. From hydrogen treated samples, μ-LEED showed at first a clear (1 × 1 pattern, but within minutes, a pattern containing strong superstructure spots, indicating the presence of twisted graphene layers. The LEED electron beam was found to induce local desorption of hydrogen. Heating a hydrogenated C-face graphene sample did not restore the quality of the original as-grown sample.

  20. Kandidiasis di Mulut akibat Khemoterapi dan Penatalaksanaannya

    Directory of Open Access Journals (Sweden)

    Sri Budiarti Wonso Hardjono

    2016-10-01

    Full Text Available Latar belakang: kandidiasis (kandidosis adalah infeksi jamur yang disebabkan oleh spesies Candida biasanya Candida albicans. Faktor predisposisi yang memicu kandidiasis adalah terganggunya ekologi mulut karena antara lain pemakaian antibiotika, kortikosteroid, penyakit kronis dan keganasan, beberapa gangguan darah; terapi radiasi di leher dan kepala; khemoterapi; leukimia, obat sitotoksik, juga kebersihan mulut yang buruk. Tujuan: melaporkan kasus kandidiasis di mulut karena khemoterapi dan penatalaksanaannya. Kasus dan penatalaksanaannya: seorang anak laki-laki umur 3 tahun 11 bulan penderita Leukimia Limfoblastik Akut (LLA sedang dalam perawatan khemoterapi menderita kandidiasis di mulut sehingga mengalami disfoni dan disfagia. Makanan dimasukkan lewat hidung. Klinis pasien terlihat lemah infus lewat tangan. Dalam mulut terlihat patch putih tebal menutupi permukaan dorsal dan ventral lidah, palatum durum dan ventral lidah, palatum durum dan molle, mukosa pipi kanan kiri dan gingiva rahang atas dan bawah. Pasien disedasi untuk dilakukan pengerokan lapisan kandida di mulut; pemberian Nystatin solution dan ketokonazol dilanjutkan. Pengerokan psedomembran kandidiasis telah memberikan hasil yang memuaskan, satu minggu kemudian rongga mulut pasien sudah terlihat bersih, pasien sudah dapat makan minum melalui mulut, juga sudah dapat berbicara lagi/tidak serah. Kesimpulan: Pembersihan jamur dengan pengerokan telah dilakukan, kandidiasis pseudomembran dapat diangkat dan mulut pasien sudah bersih, pasien dapat makan dan berbicara lagi.   Background: Candidiasis (candidosis is an fungal infection caused by Candida species usually Candida albicans. Predisposing factors which trigger candidiasis are the ecological disruption caused by use of oral antibiotics, corticosteroids, malignancy and chronic disease; some blood disorders; head and neck radiation; chemotherapy; leukimia, cytotoxic drugs, as well as poor oral hygiene. Aim: To report a case of

  1. PERSEPSI NEGATIF PASIEN KANKER PAYUDARA DAN KOLOREKTAL TERHADAP KEMOTERAPI DAN RADIOTERAPI DI RUMAH SAKIT DI KOTA DENPASAR, BALI

    Directory of Open Access Journals (Sweden)

    Gede Wara Samsarga Samsarga

    2015-01-01

    Full Text Available Terapi adjuvan yang biasanya diberikan pada pasien kanker payudara dan kanker kolorektal adalah kemoterapi dan radioterapi. Terapi adjuvan biasanya diberikan setelah terapi primer untuk meningkatkan angka kesembuhan penyakit, mencegah rekurensi, dan membunuh sel-sel kanker yang tersisa ataupun yang telah bermetastasis (terutama mikrometastasis. Terapi adjuvan juga berfungsi sebagai terapi paliatif untuk meningkatkan harapan hidup pasien kanker. Dalam kenyataannya banyak pasien kanker, khususnya kanker payudara dan kolorektal yang menghindari tindakan kemoterapi dan radioterapi. Dari 38 orang pasien kanker payudara dan kolorektal, didapatkan bahwa 26,3% takut gagal, 39,5% takut efek samping, 7,9% biaya yang mahal, 10,5% karena berlangsung dalam jangka waktu yang lama, dan 15,8% tidak takut terhadap kemoterapi dan radioterapi. Hasil penelitian ini menunjukkan bahwa tingkat pemahaman pasien kanker payudara dan kanker kolorektal terhadap tindakan kemoterapi dan radioterapi masih cukup rendah dimana 68,4% sampel tidak tahu dan tidak mengerti tentang tindakan kemoterapi dan radioterapi. Pemahaman yang kurang tentang tindakan kemoterapi dan radioterapi ini nantinya dapat mengakibatkan timbulnya persepsi negatif terhadap tindakan kemoterapi dan radioterapi. Maka dari itu sangat diperlukan adanya suatu edukasi yang baik bagi setiap pasien tentang penyakit dan modalitas terapi yang akan diberikan. Dokter diharapkan mampu untuk mengubah persepsi negatif pasien terkait tindakan kemoterapi dan radioterapi.  

  2. M. Quraish Shihab dan Rasionalisasi Tafsir

    Directory of Open Access Journals (Sweden)

    Afrizal Nur

    2012-06-01

    Full Text Available Kesempurnaan Islam adalah karena bersumberkan kepada al-Qur’an dan Sunnah, kedua sumber ini melahirkan peraturan atau popular dengan istilah syari’at. Islam menuntut umat nya untuk mendalami dan menghayati ayat-ayat yang terkandung didalam kitab suci al-Qur’an karena mempunyai maksud tersendiri, maka oleh karena nya tafsir mengambil peranan yang strategis untuk memahami dan mengungkap rahasia keagungan khazanah pada setiap ayat al-Qur’an. Berdasar motifasi tinggi untuk memahami al-Qur’an, banyak ulama di Indonesia yang berkosentrasi untuk menjelaskan dan menafsirkan al-Qur’an, dalam sejrah aktifitas penafsiran al-Qur’an berawal dari Syeikh Abdurra’uf al-Singkli pada abad ke 17M sampai saat ini adalah era nya M.Quraish Shihab. Tokoh tafsir yang terakhir ini tidak pernah absent dan ketinggalan di kaji dan di analisa oleh para komunitas akademisi tafsir baik dalam bentuk kajian kritik ataupun mendukung pencapaian prestasi kitab tafsir yang diberi nama al-Mishbah ini. Kritikan yang selalu dapat perhatian utama akademisi tafsir meliputi pandangan-pandangan rasional Quraish Shihab yang sering kali menjadi tidak rasional disebabkan tidak mengikuti dan menyalahi pandangan jumhur ulama. Oleh sebab itu penulis tidak ingin ketinggalan menyumbangkan pemikiran dalam bentuk usaha intelektual alah kadarnya yang dimiliki untuk menempatkan tafsir al-Mishbah kemartabat yang tinggi di tangga samudera karya tafsir ulama tafsir Indonesia

  3. FAKTOR PERSONAL DAN SITUASIONAL PENERIMAAN PESAN DAKWAH

    Directory of Open Access Journals (Sweden)

    Enung Asmaya

    2017-02-01

    Full Text Available The da’wa messages are not necessarily able to subdue mad’u. Subjugation and readiness of mad’u is influenced by personal and situational factors which are always intertwined in giving rulings behavior. Personal factors is surrounding the biological and sociopsychological aspects. Biological aspects such as needs and aspects sociopsychological human basic form of the condition and cognitive, affective and psychomotor of mad’u. The situational factors may include environmental systems, culture, norms, architectural design and the like. Social situation is also part of the reason for mad’u to accept or reject the message of da’wa.   Pesan dakwah tidak serta-merta dapat menundukkan mad’u. Penundukan dan kesiapan mad’u dipengaruhi faktor personal dan situasional yang senantiasa berkelindan dalam memberikan putusan-putusan perilaku. Faktorfaktor personal melingkupi aspek biologis dan sosiopsikologis. Aspek biologis berupa kebutuhan-kebutuhan dasar manusia dan aspek sosiopsikologis berupa kondisi dan kemampuan kognitif, afeksi dan konasi mad’u. Adapun faktor situasional dapat berupa sistem lingkungan, budaya, norma, design arsitektur dan sejenisnya. Kondisi sosial juga menjadi alasan mad’u dalam menerima atau menolak pesan dakwah.

  4. APA DAN MANA DALAM KALIMAT DEKLARATIF

    Directory of Open Access Journals (Sweden)

    Sri Puji Astuti

    2016-06-01

    Full Text Available Kalimat merupakan salah satu sarana untuk menyampaikan maksud pembicara atau penulis kepada pendengar atau pembaca. Untuk menyampaikan informasi digunakan kalimat deklaratif. Dalam kalimat deklaratif sering ditemui kata apa dan mana serta bentuk turunannya. Bagaimana kehadiran apa dan mana serta bentuk turunannya dalam kalimat deklaratif dibahas dalam makalah ini. Teori yang digunakan untuk menganalisis adalah teori stuktural. Pengumpulan data dilakukan dengan cara menyimak pemakaian bahasa. Dalam analisis data digunakan metode distribusional yaitu metode analisis data yang berupa penghubungan aantarfenomena dalam bahasa tertentu itu sendiri  Adapun teknik yang d.igunakan dalam penelitian ini adalah teknik delisi, substitusi, dan teknik parafrasa. Dari hasil penelitian disimpilkan  bahwa apa dan mana serta bentuk tuturannya jika terdapat dalam kalimat deklaratif bukan merupakan interogativa. Kehadiran apa dan mana serta bentuk tuturannya dalam kalimat deklaratif ada yang bersifat wajib ada yang bersifat opsional. Apa dan mana serta bentuk turunannya  bersifat opsional jika dalam kalimat deklaratif apa dan mana serta bentuk tuturannya diikuti atau didahului oleh kata yang mempunyai makna yang sama

  5. HASIL ANALISIS VITAMIN A DAN β-KAROTEN BAHAN MAKANAN SUMBER VITAMIN A DAN KAROTEN DENGAN METODE HPLC

    Directory of Open Access Journals (Sweden)

    Yuniar Rosmalina

    2012-11-01

    Full Text Available Telah dilakukan analisis vitamin A DAN β-Karoten terhadap beberapa jenis pangan dengan menggunakan metode HPLC. Analisis dilakukan terhadap 9 jenis serealia dan umbi-umbian, 3 jenis kacang-kacangan, 40 jenis sayuran, 11 jenis daging dan hasilnya, 7 jenis telur dan hasilnya, 8 jenis ikan, 12 jenis buah-buahaan, dan 7 jenis kelompok lain-lain. Hasilnya menunjukkan sumber β-Karoten yang tinggi pada kelompok serealia dan umbi-umbian adalah umbi jalar, pada kelompok sayuran adalah daun katuk, daun pepaya, daun singkong, daun melinjo, daun talas dan daun sintrong, pada kelompok telur adalah telur bebek, pada kelompok buah-buahan adalah mangga golek dan mangga gedong. Sedangkan kelompok kacang-kacangan dan kelompok daging kandungan β-Karotennya rendah. Hati ayam, hati bebek, dan hati kambing merupakan sumber vitamin A yang tinggi, sedangkan pada kelompok ikan didapati ikan lele mempunyai kandungan vitamin A yang lebih tinggi dibandingkan jenis ikan lainnya.

  6. Sistem Komputerisasi Pengolahan Buku Induk Pegawai Pada UPT Dinas Pendidikan Pemuda Dan Olahraga Kecamatan Banjarmangu Berbasis PHP Dan MYSQL

    Directory of Open Access Journals (Sweden)

    Elisa Usada

    2011-11-01

    Full Text Available Permasalahan yang akan dibahas adalah bagaimana membuat sistem pengolahan buku induk pegawai di UPT Dinas Pendidikan Pemuda dan Olahraga Kecamatan Banjarmangu berbasis PHP dan MySQL. Sistem pengolahan buku induk pegawai  berbasis PHP dan MySQL ini dirancang komputerisasi menggunakan PHP dan database MySQL dengan tujuan agar pengolahan data pegawai di UPT Dinas Pendidikan Pemuda dan Olahraga Kecamatan Banjarmangu dapat terpusat. Metode penelitian yang digunakan adalah menggunakan metode waterfall. Sistem pengolahan buku induk pegawai ini menggunakan jaringan client server dan dapat diakses oleh administrator dan Kepala UPT dan Pegawai. Kelebihan dari sistem pengolahan ini adalah dilindungi password dan hak akses yang berbeda untuk setiap user sehingga keamanan data dapat terjamin, sedangkan kekurangannya adalah program yang dihasilkan belum maksimal karena mengkhususkan data pegawai pada buku induk saja. Saran dari sistem pengolahan ini yaitu pengembangan dari segi keamanan data, kelengkapan data, dan ketelitian sistem dalam input data untuk mengurangi kesalahan.

  7. Perancangan dan Implementasi Presensi Digital Guru dan Karyawan SMA Negeri 9 Semarang

    Directory of Open Access Journals (Sweden)

    Th. Didot Septiawan

    2016-04-01

    Full Text Available Berdasarkan surat edaran dari Kepala Dinas Pendidikan Kota Semarang, terhitung mulai Januari 2015 tiap sekolah dihimbau untuk beralih dari sistem presensi manual menjadi digital. Hingga awal Maret ini, presensi guru dan karyawan di SMA Negeri 9 Semarang masih dilakukan secara manual. Maka diperlukan sebuah penelitian untuk merancang dan menerapkan sistem presensi digital bagi SMA Negeri 9 Semarang. Tahapan penelitian meliputi perencanaan, analisis, perancangan, implementasi, pengujian, dan pemeliharaan. Perangkat lunak dibangun dengan framework PHP Phalcon, basis data MySQL, dan aplikasi webserver Nginx pada sistem operasi Ubuntu 14.04. Mesin presensi dengan metode pengenalan wajah dipilih untuk mendapatkan data kehadiran yang bersifat autentik. Pengujian dilakukan dengan metode kotak hitam dan kotak putih. Semua kebutuhan fungsional telah diimplementasikan pada aplikasi web dan kebutuhan non-fungsional pun telah terpenuhi. Sistem presensi digital ini menjadi solusi bagi SMA Negeri 9 Semarang dalam usaha uji coba penggunaan presensi digital.

  8. Reliability Assessment of SiC Power MOSFETs From The End User's Perspective

    DEFF Research Database (Denmark)

    Karaventzas, Vasilios Dimitris; Nawaz, Muhammad; Iannuzzo, Francesco

    2016-01-01

    The reliability of commercial Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is investigated, and comparative assessment is performed under various test environments. The MOSFETs are tested both regarding the electrical properties of the dies and the packaging...

  9. Photoluminescence topography of fluorescent SiC and its corresponding source crystals

    DEFF Research Database (Denmark)

    Wilhelm, M.; Kaiser, M.; Jokubavicus, V.

    2013-01-01

    The preparation and application of co-doped polycrystalline SiC as source in sublimation growth of fluorescent layers is a complex topic. Photoluminescence topographies of luminescent 6H-SiC layers and their corresponding source crystals have been studied in order to investigate the dependence...

  10. Localized Surface Plasmon on 6H SiC with Ag Nanoparticles

    DEFF Research Database (Denmark)

    Wei, Yi; Fadil, Ahmed; Ou, Haiyan

    2017-01-01

    ) of the emissions of the donor-acceptor pairs of the SiC substrate. Roomtemperature measurements of photoluminescence (PL), transmittance and time-resolved photoluminescence (TRPL) were applied to characterize the LSP resonances. Through the finitedifference time-domain (FDTD) simulation of the LSP resonance...

  11. Synthesis and characterization of AA 6061- Graphene - SiC hybrid nanocomposites processed through microwave sintering

    Science.gov (United States)

    Jauhari, Siddhartha; Prashantha Kumar, H. G.; Xavior, . M. Anthony

    2016-09-01

    As one of the most essential industrial and engineering materials, Aluminum alloy 6061 have been extensively used in automobile industries and many engineering applications due to its impending properties like low density, good structural rigidity, feasibility to incorporate and enhance the strength by addition of various reinforcing materials. The essential criteria in enhancing the properties without sacrificing the ductility is always challenging in Aluminum and its alloys based composites. In the recent years, enormous research has been carried on ceramic based and carbon based reinforcement materials used in Aluminum metal matrix composites. But the combination of both is never tried so far due to lack of processing methods. The current research work is carried out to process, synthesize and perform the characterization of Al 6061 matrix nanocomposites with Graphene of flake size 10 μm and SiC of particle size 10 pm as reinforcement combinations in various proportions (weight percentage) which are carried out through powder metallurgy (PM) approach. The powders are processed through ultrasonic liquid processing method and the mixtures were ball milled by adding SiC particles followed by uniaxial hot compaction. Thus prepared compacts are sintered (conventional and microwave) and mechanical properties like hardness, density are investigated as a function of Graphene and SiC concentrations (weight fraction). Relevant strengthening mechanism involved in the Al6061 - Graphene -SiC composites in comparison with monolithic Al 6061 alloy were discussed.

  12. Study on porosity of ceramic SiC using small angle neutron scattering

    Institute of Scientific and Technical Information of China (English)

    李际周; Y.Ito

    1996-01-01

    The mechanical properties of functional heat-resistant ceramics SiC are significantly influenced by the concentration and idmensions of pores.Small angle neutron scattering measurements for 3 SiC samples with different densities are performed on C1-2 SANS instrument of the University of Tokyo.Two groups of the neutron data are obtained using 8 and 16m of secondary flight path,1 and 0.7 nm of neutron wave lengths,respectively,After deduction of background measurement and transmission correction,both neutron data are linked up with each other,The patterns of neutron data of 3 samples with Q range from 0.028-0.5nm-1 are almost with axial symmetry,showing that the shape of pores is almost spherical.Using Mellin transform,size distributions of pores in 3 samples are obtained.The average size (-19nm)of pores for hot-pressed SiC sample with higher density is smaller than the others (-21nm).It seems to be the reason why the density of hot-pressed SiC sample is higher than not hot-pressed sample.

  13. Conformal Thin Film Packaging for SiC Sensor Circuits in Harsh Environments

    Science.gov (United States)

    Scardelletti, Maximilian C.; Karnick, David A.; Ponchak, George E.; Zorman, Christian A.

    2011-01-01

    In this investigation sputtered silicon carbide annealed at 300 C for one hour is used as a conformal thin film package. A RF magnetron sputterer was used to deposit 500 nm silicon carbide films on gold metal structures on alumina wafers. To determine the reliability and resistance to immersion in harsh environments, samples were submerged in gold etchant for 24 hours, in BOE for 24 hours, and in an O2 plasma etch for one hour. The adhesion strength of the thin film was measured by a pull test before and after the chemical immersion, which indicated that the film has an adhesion strength better than 10(exp 8) N/m2; this is similar to the adhesion of the gold layer to the alumina wafer. MIM capacitors are used to determine the dielectric constant, which is dependent on the SiC anneal temperature. Finally, to demonstrate that the SiC, conformal, thin film may be used to package RF circuits and sensors, an LC resonator circuit was fabricated and tested with and without the conformal SiC thin film packaging. The results indicate that the SiC coating adds no appreciable degradation to the circuits RF performance. Index Terms Sputter, silicon carbide, MIM capacitors, LC resonators, gold etchants, BOE, O2 plasma

  14. Rapid manufacturing of SiC molds with micro-sized holes using abrasive water jet

    Institute of Scientific and Technical Information of China (English)

    Bo-Sung SHIN; Kang-Su PARK; Yeon-Kyoung BAHK; Sun-Ki PARK; Jung-Han LEE; Jeung-Sang GO; Myung-Chang KANG; Chae-Moon LEE

    2009-01-01

    Silicon carbide (SIC) is highly wear resistant with good mechanical properties, including high temperature strength, excellent chemical resistance, and high thermal conductivity and thermal shock resistance. SiC molds, which can be produced with diverse microstructural features, are now widely used in glass molding owing to their excellent characteristics, and also have potential applicability in IT industries. SiC molds are traditionally fabricated by silicon micromachining or dicing. The fabrication cost of silicon micromachining is very high, however, because several expensive masks are needed. Furthermore, the fabrication time is very long. Meanwhile, it is difficult to make micro-patterned molds with arbitrary shapes using dicing saws. Abrasive water jet (AWJ) is widely applied to cut and drill very brittle, soft and fibrous materials. It offers high energy density, the absence of a heat affected zone(HAZ), high performance, and an environment friendly process. In spite of these advantages, micro-hole drilling via conventional AWJ processing suffers from notable shortcomings. We proposed a new abrasive supplying method of AWJ. The proposed method reduces frosting phenomena, and provides micro-machining of AWJ. The characteristics of a hole machined was investigated by the proposed AWJ process according to the ratio of water and abrasives. With the optimal experimental conditions, 3 × 3 array SiC molds with the diameter of 700 μm and depth of 900 μm were successfully manufactured.

  15. SiC lightweight telescopes for advanced space applications. II - Structures technology

    Science.gov (United States)

    Anapol, Michael I.; Hadfield, Peter; Tucker, Theodore

    1992-01-01

    A critical technology area for lightweight SiC-based telescope systems is the structural integrity and thermal stability over spaceborne environmental launch and thermal operating conditions. Note, it is highly desirable to have an inherently athermal design of both SiC mirrors and structure. SSG has developed an 8 inch diameter SiC telescope system for brassboard level optical and thermal testing. The brassboard telescope has demonstrated less than 0.2 waves P-V in the visible wavefront change over +50 C to -200 C temperature range. SSG has also fabricated a SiC truss structural assembly and successfully qualified this hardware at environmental levels greater than 3 times higher than normal Delta, Titan, and ARIES launch loads. SSG is currently developing two SiC telescopes; an 20 cm diameter off-axis 3 mirror re-imaging and a 60 cm aperture on-axis 3 mirror re-imager. Both hardware developments will be tested to flight level environmental, optical, and thermal specifications.

  16. Selected mechanical properties of aluminum composite materials reinforced with SiC particles

    Directory of Open Access Journals (Sweden)

    A. Kurzawa

    2008-07-01

    Full Text Available This work presents the results of research concerning influence of ceramic particles’ content of silicon carbide on selected mechanical properties of type AW-AlCu4Mg2Mn - SiC composite materials. Composites produced of SiC particles with pressure infiltration method of porous preform and subject to hot plastic forming in the form of open die forging were investigated. The experimental samples contained from 5% up to 45% of reinforcing SiC particles of 8÷10μm diameter. Studies of strength properties demonstrated that the best results, in case of tensile strength as well as offset yield strength, might be obtained while applying reinforcement in the amount of 20-25% vol. of SiC. Application of higher than 25% vol. contents of reinforcing particles leads to gradual strength loss. The investigated composites were characterized by very high functional properties, such as hardness and abrasive wear resistance, whose values increase strongly with the increase of reinforcement amount. The presented results of the experiments shall allow for a more precise component selection of composite materials at the stage of planning and design of their properties.

  17. Mission-profile-based stress analysis of bond-wires in SiC power modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Iannuzzo, Francesco; Blaabjerg, Frede

    2016-01-01

    This paper proposes a novel mission-profile-based reliability analysis approach for stress on bond wires in Silicon Carbide (SiC) MOSFET power modules using statistics and thermo-mechanical FEM analysis. In the proposed approach, both the operational and environmental thermal stresses are taken i...

  18. Photoelectrochemistry and Etching of SiC: a Comparison with Si

    NARCIS (Netherlands)

    Kelly, J.J.; van Dorp, D.H.; Weyher, J.L.

    2007-01-01

    The anodic electrochemistry and etching of the group IV compound semiconductor SiC was studied in both KOH and acidic fluoride solutions. The results for p-type and n-type electrodes are compared with those obtained for the group IV elemental semiconductor Si. We point out a number of interesting ap

  19. Thermal annealing of SiC thin films with varying stoichiometry

    Energy Technology Data Exchange (ETDEWEB)

    Kuenle, Matthias [Fraunhofer Institute for Solar Energy Systems, Heidenhofstrasse 2, 79110 Freiburg (Germany)], E-mail: matthias.kuenle@ise.fraunhofer.de; Janz, Stefan [Fraunhofer Institute for Solar Energy Systems, Heidenhofstrasse 2, 79110 Freiburg (Germany); Eibl, Oliver [Eberhard-Karls-Universitaet, Tuebingen, Institute for Applied Physics, Auf der Morgenstelle 10, 72076 Tuebingen (Germany); Berthold, Christoph; Presser, Volker; Nickel, Klaus-Georg [Eberhard-Karls-Universitaet, Tuebingen, Institute for Geoscience, Applied Mineralogy, Wilhelmstrasse 56, 72074 Tuebingen (Germany)

    2009-03-15

    Thin films of amorphous hydrogenated silicon carbide (a-SiC:H) with varying stoichiometry of silicon and carbon were prepared by Plasma Enhanced Chemical Vapour Deposition (PECVD). After deposition a subsequent rapid thermal annealing was carried out at 900, 1100 and 1300 deg. C. The as-deposited and annealed SiC thin films were investigated by X-ray diffraction (XRD), cross-section and plane view transmission electron microscopy (TEM), Fourier-Transformed Infrared (FTIR) and Raman spectroscopy. The deposited films were amorphous directly after deposition and became nanocrystalline after annealing at 1300 deg. C. This was verified by XRD measurements. Microvoids were found in all films investigated by TEM. Densification and crystallisation as well as cooling introduced tensile stresses within the annealed SiC film and lead eventually to crack formation in the film. The annealed stoichiometric SiC film shows v-shaped extended defects at the Si-SiC interface likely formed during the annealing at high temperatures. FTIR and Raman spectroscopy showed a strong influence of initial film properties such as hydrogen content and binding structure on the internal structure of the SiC thin films after annealing.

  20. Silicon Carbide (SiC) Power Processing Unit (PPU) for Hall Effect Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR project, APEI, Inc. is proposing to develop a high efficiency, rad-hard 3.8 kW silicon carbide (SiC) power supply for the Power Processing Unit (PPU) of...

  1. An Investigation of Abrasive Wear Behaviour of Al 2014-SiC Composites

    Science.gov (United States)

    Çalin, Recep; Cilasun, Niyazi Selçuk

    2015-04-01

    In this study, the effects of SiC reinforcement volume fractions on hardness, porosity and abrasive wear behaviour were examined in Al 2014-SiC (composites (MMCs) of 3%, 6% and 12% reinforcement-volume (R-V) ratios produced by melt-stirring. Abrasive wear tests were carried out by 320 mesh Al2O3 abrasive paper and a pin-on-disc wear test apparatus, under 10N, 20N and 30N load, and at 0.2 ms-1 sliding speed. The same specimens were tested by 150, 240 and 320 mesh abrasive paper at 0.2 ms-1 sliding speed, under 10N, 20N and 30N load. After the tests, the microstructures of the worn surfaces were examined with scanning electron microscope (SEM) studies and EDS analyses. Besides, the amount of hardness and porosity of the specimens were identified. It was recorded that the amounts of hardness and porosity increases as the SiC reinforcement in the composite increases. The highest amount of abrasive wear was recorded in the specimens with 3% reinforcements. It was identified that the amount of abrasive wear decreases while the SiC reinforcement in the composite structure increases by volume, and that the amount of porosity and reinforcement volume (R-V) ratio are important parameters in abrasive wear.

  2. Molecular Dynamics Simulations of Atomic H Etching SiC Surface

    NARCIS (Netherlands)

    Sun, W.; Liu, H.; Lin, L.; Zhao, C. L.; Lu, X. D.; He, P. N.; Gou, F.

    2012-01-01

    In this paper, molecular dynamics simulations were performed to study interactions between atomic H and SiC, silicon carbon surfaces were continuously bombarded by atomic H with different energies. The Tersoff-Brenner potentials were implemented. The simulation results show that with increasing

  3. Laser surface alloying of aluminum (AA1200) with Ni and SiC Powders

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-12-01

    Full Text Available An Nd:YAG laser was used for surface alloying of aluminum AA1200. The alloying powder was a mixture of Ni and SiC in different ratios. A study of the microstructures obtained after alloying was conducted using optical and scanning electron...

  4. Laser alloying of Al with mixed Ni, Ti and SiC powders

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-11-01

    Full Text Available Laser alloying of aluminium AA1200 was performed with a 4.4kW Rofin Sinar Nd:YAG laser to improve the surface hardness. Alloying was carried out by depositing Ni, Ti and SiC powders of different weight ratios on the aluminium substrate. The aim...

  5. Laser alloying of AI with mixed Ni, Ti and SiC powders

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-03-01

    Full Text Available Laser alloying of aluminium AA1200 was performed with a 4.4kW Rofin Sinar Nd:YAG laser to improve the surface hardness. Alloying was carried out by depositing Ni, Ti and SiC powders of different weight ratios on the aluminum substrate. The aim...

  6. Analysis of the residual stress in Al2O3-SiC nanocomposites

    Institute of Scientific and Technical Information of China (English)

    王宏志; 高濂; 郭景坤

    1999-01-01

    The residual stress in Al2O3-SiC nanocomposites was measured by the X-ray diffraction method. A mode was established to calculate the residual stress, which accorded with the results measured by the XRD method. The strengthening and toughening mechanism was also discussed.

  7. Omnidirectional luminescence enhancement of fluorescent SiC via pseudoperiodic antireflective subwavelength structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Yakimova, Rositza;

    2012-01-01

    In the present work, an approach of fabricating pseudoperiodic antireflective subwavelength structures (ARS) on fluorescent SiC by using self-assembled etch mask is demonstrated. By applying the pseudoperiodic (ARS), the average surface reflectance at 6° incidence over the spectral range of 390-7...

  8. Antireflective SiC Surface Fabricated by Scalable Self-Assembled Nanopatterning

    DEFF Research Database (Denmark)

    Ou, Yiyu; Fadil, Ahmed; Ou, Haiyan

    2016-01-01

    An approach for fabricating sub-wavelength antireflective structures on SiC material is demonstrated. A time-efficient scalable nanopatterning method by rapid thermal annealing of thin metal film is applied followed by a dry etching process. Size-dependent optical properties of the antireflective...

  9. CO oxidation catalyzed by silicon carbide (SiC) monolayer: A theoretical study.

    Science.gov (United States)

    Wang, Nan; Tian, Yu; Zhao, Jingxiang; Jin, Peng

    2016-05-01

    Developing metal-free catalysts for CO oxidation has been a key scientific issue in solving the growing environmental problems caused by CO emission. In this work, the potential of the silicon carbide (SiC) monolayer as a metal-free catalyst for CO oxidation was systematically explored by means of density functional theory (DFT) computations. Our results revealed that CO oxidation reaction can easily proceed on SiC nanosheet, and a three-step mechanism was proposed: (1) the coadsorption of CO and O2 molecules, followed by (2) the formation of the first CO2 molecule, and (3) the recovery of catalyst by a second CO molecule. The last step is the rate-determining one of the whole catalytic reaction with the highest barrier of 0.65eV. Remarkably, larger curvature is found to have a negative effect on the catalytic performance of SiC nanosheet for CO oxidation. Therefore, our results suggested that flat SiC monolayer is a promising metal-free catalyst for CO oxidation.

  10. Switching Investigations on a SiC MOSFET in a TO-247 Package

    DEFF Research Database (Denmark)

    Anthon, Alexander; Hernandez Botella, Juan Carlos; Zhang, Zhe;

    2014-01-01

    package, has a major influence on the switching energy. Crucial design guidelines for an improved double pulse test circuit are introduced which are used for practical investigations on the switching behavior. Switching energies of a SiC MOSFET in a TO-247 package is measured depending on varying gate...

  11. Residual stress measurements in an SiC continuous fiber reinforced Ti matrix composite

    NARCIS (Netherlands)

    Willemse, P.F.; Mulder, F.M.; Wei, W.; Rekveldt, M.Th.; Knight, K.S.

    2000-01-01

    During the fabrication of ceramic fiber reinforced metal matrix composites mismatch stresses will be introduced due to differences in thermal expansion coefficients between the matrix and the fibers. Calculations, based on a coaxial cylinder model, [1 and 2] predict that, for a Ti matrix SiC

  12. Temperature dependence of a microstructured SiC coherent thermal source

    Science.gov (United States)

    Hervé, Armande; Drévillon, Jérémie; Ezzahri, Younès; Joulain, Karl; De Sousa Meneses, Domingos; Hugonin, Jean-Paul

    2016-09-01

    By ruling a grating on a polar material that supports surface phonon-polaritons such as silicon carbide (SiC), it is possible to create directional and monochromatic thermal sources. So far, most of the studies have considered only materials with room temperature properties as the ones tabulated in Palik's handbooks. Recently, measurements have provided experimental data of the SiC dielectric function at different temperatures. Here we study, numerically, the effect of the temperature dependence of the dielectric function on the thermal emission of SiC gratings (1D grating, in a first approach), heated at different temperatures. When materials are heated, the position of the grating emissivity peak shifts towards higher wavelength values. A second consequence of the temperature dependence of optical properties is that room temperature designed gratings are not optimal for higher temperatures. However, by modifying the grating parameters, it is possible to find an emission peak, with a maximum of emissivity near 1, for each temperature. We tried first to catch some patterns in the emissivity variation. Then, we obtained a grating, which leads to an optimum emissivity for all available temperature data for SiC.

  13. pH sensitivity of Si-C linked organic monolayers on crystalline silicon surfaces

    NARCIS (Netherlands)

    Faber, Erik Jouwert; Sparreboom, Wouter; Groeneveld, Wilrike; de Smet, Louis C.P.M.; Bomer, Johan G.; Olthuis, Wouter; Zuilhof, Han; Sudholter, Ernst; Sudhölter, Ernst J.R.; Bergveld, Piet; van den Berg, Albert

    2007-01-01

    The electrochemical behaviour of Si-C linked organic monolayers is studied in electrolyte-insulator-Si devices, under conditions normally encountered in potentiomeric biosensors, to gain fundamental knowledge on the behaviour of such Si electrodes under practical conditions. This is done via

  14. 40 CFR 372.23 - SIC and NAICS codes to which this Part applies.

    Science.gov (United States)

    2010-07-01

    ... dresses or gowns, or women's, misses' and girls' dresses cut and sewn from purchased fabric (except... Except facilities primarily engaged in Music copyright authorizing use, Music copyright buying and licensing, and Music publishers working on their own account (previously classified under SIC 8999,...

  15. Characterization and Comparison of Planar and Trench Silicon Carbide (SiC) Power MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhiqiang [ORNL; Chinthavali, Madhu Sudhan [ORNL; Campbell, Steven L [ORNL

    2016-01-01

    This paper presents a comprehensive evaluation and experimental comparison of silicon carbide power MOSFETs through double pulse test. First, a universal hardware platform is designed and developed to test power semiconductor devices with various device packages and measuring requirements. Using the developed platform, the static characteristics and switching performance of the two types of SiC MOSFETs (one planar and one trench type) are evaluated under different case temperatures from 25 oC to 175 oC. Based on the evaluation data, a comparison of both SiC MOSFETs is conducted in terms of their on-state resistance, switching loss, and temperature dependent behavior. It is found that the latest trench SiC MOSFETs present similar switching loss while much lower conduction loss compared to existing commercial planar SiC MOSFETs. Moreover, the trench devices show a nearly temperature independent switching loss, which is beneficial to suppress the potential thermal runaway issue under high temperature continuous operation.

  16. Few layer graphene synthesis via SiC decomposition at low temperature and low vacuum

    Science.gov (United States)

    Kayali, Emre; Mercan, Elif; Emre Oren, Ersin; Cambaz Buke, Goknur

    2016-04-01

    Based on the large-scale availability and good electrical properties, the epitaxial graphene (EG) on SiC exhibits a big potential for future electronic devices. However, it is still necessary to work continuously on lowering the formation temperature and vacuum values of EG while improving the quality and increasing the lateral size to fabricate high-performance electronic devices at reduced processing costs. In this study, we investigated the effect of the presence of Mo plate and hydrogen atmosphere as well as the vacuum annealing durations on SiC decomposition. Our studies showed that the graphene layers can be produced at lower annealing temperatures (1200 °C) and vacuum values (10-4 Torr) in the presence of Mo plate and hydrogen. For high quality continuous graphene formation, Mo plate should be in contact with SiC. If there is a gap between Mo and SiC, non-wetting oxide droplets on few layer graphene (FLG) are recorded. Moreover, it is found that the morphology of these islands can be controlled by changing the annealing time and atmosphere conditions, and applying external disturbances such as vibration.

  17. SiC MODIFICATIONS TO MELCOR FOR SEVERE ACCIDENT ANALYSIS APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Brad J. Merrill; Shannon M Bragg-Sitton

    2013-09-01

    The Department of Energy (DOE) Office of Nuclear Energy (NE) Light Water Reactor (LWR) Sustainability Program encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. The Fuels Pathway within this program focuses on fuel system components outside of the fuel pellet, allowing for alteration of the existing zirconium-based clad system through coatings, addition of ceramic sleeves, or complete replacement (e.g. fully ceramic cladding). The DOE-NE Fuel Cycle Research & Development (FCRD) Advanced Fuels Campaign (AFC) is also conducting research on materials for advanced, accident tolerant fuels and cladding for application in operating LWRs. To aide in this assessment, a silicon carbide (SiC) version of the MELCOR code was developed by substituting SiC in place of Zircaloy in MELCOR’s reactor core oxidation and material property routines. The purpose of this development effort is to provide a numerical capability for estimating the safety advantages of replacing Zr-alloy components in LWRs with SiC components. This modified version of the MELCOR code was applied to the Three Mile Island (TMI-2) plant accident. While the results are considered preliminary, SiC cladding showed a dramatic safety advantage over Zircaloy cladding during this accident.

  18. The SIC Are Dying: New Federal Industry Code on the Way.

    Science.gov (United States)

    Quint, Barbara

    1996-01-01

    Standard Industrial Classification (SIC) codes have structured most federal and many private collections of industry statistics. This article introduces the new industry classification hierarchy called the North American Industry Classification System (NAICS) and its effects on searchers. A sidebar includes sources of information on the new code.…

  19. Modeling and Testing Miniature Torsion Specimens for SiC Joining Development Studies for Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.; Roosendaal, Timothy J.; Borlaug, Brennan A.; Ferraris, Monica; Ventrella, Andrea; Katoh, Yutai

    2015-08-19

    The international fusion community has designed a miniature torsion specimen for neutron irradiation studies of joined SiC and SiC/SiC composite materials. Miniature torsion joints based on this specimen design were fabricated using displacement reactions between Si and TiC to produce Ti3SiC2 + SiC joints with CVD-SiC and tested in torsion-shear prior to and after neutron irradiation. However, many of these miniature torsion specimens fail out-of-plane within the CVD-SiC specimen body, which makes it problematic to assign a shear strength value to the joints and makes it difficult to compare unirradiated and irradiated joint strengths to determine the effects of the irradiation. Finite element elastic damage and elastic-plastic damage models of miniature torsion joints are developed that indicate shear fracture is likely to occur within the body of the joined sample and cause out-of-plane failures for miniature torsion specimens when a certain modulus and strength ratio between the joint material and the joined material exists. The model results are compared and discussed with regard to unirradiated and irradiated joint test data for a variety of joint materials. The unirradiated data includes Ti3SiC2 + SiC/CVD-SiC joints with tailored joint moduli, and includes steel/epoxy and CVD-SiC/epoxy joints. The implications for joint data based on this sample design are discussed.

  20. TINJAUAN UMUM TENTANG HELPDESK DAN FRAMEWORK TERKAIT

    Directory of Open Access Journals (Sweden)

    Ali Tarmuji

    2013-04-01

    Full Text Available Penggunaan teknologi informasi dan komunikasi (TIK di suatu instansi sangat banyak dampaknya, baik positif maupun negatif. Seiring perkembangan teknologi semakin banyak pemanfaatan media TIK ini untuk membantu pelaksanaan suatu pekerjaan bahkan hampir seluruh bidang di suatu instansi. Dalam perjalanan penggunaan TIK sering muncul permasalahan-permasalahan yang jika tidak ditangani akan mengakibatkan adanya kemunduran kinerja dari bagian/seseorang yang menggunakan peralatan TIK untuk menunjang kerja mereka. Suatu instansi yang sudah sedemikian kompleksnya dalam penggunaan peralatan TIK di instansinya maka diperlukan suatu mekanisme dan unit khusus yang menangani penggunaan dan permasalahan dalam hal penggunaan TIK tersebut. Mekanisme dan unit khusus tersebut sering dinamakan tim helpdesk yang tujuan utamanya adalah menangani penyelesaian terhadap permasalahan yang muncul dari penggunaan suatu peralatan TIK tersebut sehingga mampu memperlancar kerja yang terkait. Suatu instansi dalam hal penerapan tim helpdesk memerlukan suatu perencanaan yang matang dan terorganisir. Langkah-langkah yang perlu dilakukan oleh instansi dalam implementasi tim helpdesknya antara lain, (1 membentuk tim khusus untuk menganalisis organisasinya terkait kebutuhan implementasi helpdesk tersebut, (2 membentuk organisasi helpdesk sesuai kebutuhan, (3 memilih workflow helpdesk yang disesuaikan dengan kondisi instansi, (4 memilih framework yang tepat untuk mendasari jalannya implementasi helpdesk di instansi terkait, dan (5 menuangkan aturan-aturan dasar (standard operation procedur-SOP untuk menguatkan kiprah tim helpdesk di instansi terkait.Terbentuknya tim helpdesk diharapkan dapat mengatasi permasalahan dan memberikan layanan terhadap seluruh permasalahan bidang TIK baik yang bersifat internal (pengembang aplikasi maupun seluruh permasalahan operasional aplikasi ataupun hal-hal yang berhubungan dengan sistem dan teknologi informasi dan komunikasi.