bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Neutron Irradiation on Electrical Characteristics of 4H-SiC Power Devices
Authors: Hazdra Pavel , Popelka Stanislav , Zahlava Vít
Published: July 2015

Commercial 1200V and 1700V MPS diodes and 1700V vertical JFETs produced on 4H-SiC n-type epilayers were neutron irradiated with fluences up to 4x1014 cm-2 (1 MeV neutron equivalent Si). Radiation defects and their effect on carrier removal were investigated by capacitance deep-level transient spectroscopy, I-V and C-V measurement. Results show that neutron irradiation introduces different point defects giving rise to deep acceptor levels which compensate nitrogen doping of the epilayer. The carrier removal rate increases linearly with nitrogen doping. Introduced defects deteriorate ON-state characteristics of irradiated devices while their effect on blocking characteristics is negligible. The effect of neutron irradiation can be simulated by TCAD tools using a simple model accounting for introduction of one dominant deep level (Z1/Z2 centre).
VLS Grown 4H-SiC Buried P+ Layers for JFET Lateral Structures
Authors: Sejil Selsabil , Laariedh Farah , Lazar Mihai , Carole Davy , Brylinski Christian , Planson Dominique , Ferro Gabriel , Raynaud Christophe , Morel Hervé
Published: July 2015

Lateral JFET transistors have been fabricated with N and P-type channels tentatively integrated monolithically on the same SiC wafer. Buried P+ SiC layers grown by Vapor-Liquid-Solid (VLS) selective epitaxy were utilized as source and drain for the P-JFET and as gate for the N-JFET. The ohmicity of the contacts, both on VLS grown P+ and ion implanted N+ layers, has been confirmed by Transfer Length Method (TLM) measurements. A premature leakage current is observed on the P/N junction created directly by the P+ VLS gate layer, probably due to imperfect VLS (P+) / CVD (N+) SiC interface.
27 kV, 20 A 4H-SiC n-IGBTs
Authors: van Brunt Edward , Cheng Lin , O'Loughlin Michael J. , Richmond Jim , Pala Vipindas , Palmour John W. , Tipton Charles W. , Scozzie Charles
Published: July 2015

In this work, we report our recently developed 27 kV, 20 A 4H-SiC n-IGBTs. Blocking voltages exceeding 24 kV were achieved by utilizing thick (210 μm and 230 μm), lightly doped N-drift layers with an appropriate edge termination. Prior to the device fabrication, an ambipolar carrier lifetime of greater than 10 μs was measured on both drift regions by the microwave photoconductivity decay (μPCD) technique. The SiC n-IGBTs exhibit an on-state voltage of 11.8 V at a forward current of 20 A and a gate bias of 20 V at 25 °C. The devices have a chip size of 0.81 cm2 and an active conducting area of 0.28 cm2. Double-pulse switching measurements carried out at up to 16 kV and 20 A demonstrate the robust operation of the device under hard-switched conditions; coupled thermal analysis indicates that the devices can operate at a forward current of up to 10 A in a hard-switched environment at a frequency of more than 3 kHz and a bus voltage of 14 kV.
Growth and Characterization of Thick Multi-Layer 4H-SiC Epiwafer for Very High-Voltage p-Channel IGBTs
Authors: Miyazawa Tetsuya , Nakayama Koji , Tanaka Atsushi , Asano Katsunori , Ji Shi Yang , Kojima Kazutoshi , Ishida Yuuki , Tsuchida Hidekazu
Published: July 2015

Thick multi-layer 4H-SiC epitaxial growth was investigated for very high-voltage Si-face p-channel insulated gate bipolar transistors (p-IGBTs). The multi-layer included n+ buffer, p+ field stop, and thick p- drift layers. Two processes were employed to enhance the carrier lifetime of the p- drift layer: carbon ion implantation/annealing and hydrogen annealing, and the enhanced carrier lifetime was confirmed by the open-circuit voltage decay measurement. Using the grown thick multi-layer 4H-SiC, simple pin diodes were fabricated instead of p-IGBTs to demonstrate efficient conductivity modulation in the thick p- drift layer. While the on-state voltage was high at room temperature, it decreased significantly at elevated temperatures, and attained 3.5 V at 100 A/cm2 at 200°C for the diode with the carrier lifetime enhancement processes, indicating sufficient conductivity modulation.
Silicon Carbide Nanowire Devices for Label-Free Electrical DNA Detection
Authors: Fradetal Louis , Bano Edwige , Montes Laurent , Atolini Giovanni , Stambouli Valerie
Published: July 2015

Silicon Carbide is a promising material to overtake the limitations of Si sensors used for in vivo detection. Here, two different nanodevices are presented. The first one is a SiC NWFET used for electrical detection of DNA molecules. The addition of DNA probe molecules increases the current by 25% and the hybridization with DNA targets increases by 80%. This confirms the efficiency of our sensor to detect DNA. The second one is a Metal Insulator Semicondutor capacitor composed of DNA functionalized SiC nanopillar arrays embedded in a sol-gel silicon dioxide matrix. Capacitance measurements show a singular response between 80 and 100 Hz which is attributed to the presence of DNA molecules.
Simulations of Interactions between Fast Neutrons and 4H-SiC Detectors
Authors: Biondo Stephane , Vervisch Wilfried , Ottaviani Laurent , Vervisch Vanessa , Ferrone Raffaello , Lioussy Abdallah
Published: July 2015

Among particle detectors, particle detectors based on the wide gap semiconductor materials are many used in the nuclear area. For the reliable uses in hard and severe environment, the 4H-SiC is mainly used to the realization of nuclear detector components. This is a part of the topic of the I_SMART European project which proposes to study the nuclear detection of the thermal and fast neutron and gamma rays. In this paper, we deal with the Monte Carlo simulation results of interactions between particles and 4H-SiC detector. In particular, simulation works present the results between fast neutron and 4H-SiC sensor with a comparison between the simulation and experimental results. This article tries to point out the effect of the space charge region depletion, in particular the electric field on the signal response strength.
High Voltage Wide Bandgap Photoconductive Switching
Authors: Sampayan S.E. , Bora Mihail , Brooksby Craig , Caporaso G.J. , Conway Adam , Hawkins Steve , Hickman Brad , Holmes Cliff , Nguyen Hoang , Nikolic Rebecca , Palmer Dave , Voss Lars , Wang Lisa , Waters Amy
Published: July 2015

High gain photoconductive switching using Si and GaAs was studied previously for pulsed high voltage switching. A laser is used to generate charge carriers within the material to render the bulk conductive. We have begun the study of photoconductive switching using wide bandgap materials. These materials appear to operate in a non-high gain mode and the on resistance can be directly controlled with the laser intensity over many decades. It is presently believed that the conduction mechanism may be due to (a) excitation of deep states or (b) multi-photon pumping of carriers from the valance band. We present the study of the physics processes and development of a device operating at >20-kV.
Development of SiC Power Module and Loss Evaluation in DC-DC Converter Circuit Application
Authors: Funaki Tsuyoshi , Yamamoto Shuhei , Harada Shin , Iizuka Yuji , Fukuda Kenji , Sugiki Akio , Hiratani Tatsuhiko , Kimura Hiroshi , Saitou Takao
Published: July 2015

The thermal management of power module is one of the key important issues for power conversion circuit design. SiC power module is expected to give less conduction and switching loss than conventional Si device, which enables to facilitate the thermal management of a power conversion circuit. This paper develops 2in1 Full-SiC power module and studies the applicability for 600V→300V, 15kW DC-DC buck converter. The feasible thermal design of SiC power module to serve rated operation of the converter circuit is discussed based on the elemental experiments. The developed full-SiC power module realized lower loss and smaller converter circuit than conventional-Si power module.
4H-SiC Growth from Si-Cr-C Solution under Al and N Co-Doping Conditions
Authors: Mitani Takeshi , Komatsu Naoyoshi , Takahashi Tetsuo , Kato Tomohisa , Ujihara Toru , Matsumoto Yuji , Kurashige Kazuhisa , Okumura Hajime
Published: July 2015

We have investigated the solution growth under various Al-N co-doping conditions. Both p-type and n-type 4H-SiC were successfully grown under Al-N co-doping conditions, while using the effect of Al-addition to stabilize both growth surface and polytype. The doping and electrical properties were investigated systematically. Interaction between Al and N in the incorporation process and electrical property under heavily co-doped conditions were discussed.
Graphene Ohmic Contacts to n-Type Silicon Carbide (0001)
Authors: Hertel Stefan , Finkler Andreas , Krieger M. , Weber Heiko B.
Published: July 2015

Epitaxial graphene on silicon carbide (SiC) can easily be grown by thermal decomposition. A well-defined epitaxial interface between graphene and substrate is formed, especially when the silicon face of hexagonal polytypes is employed. It is found that as-grown monolayer graphene with interfacial buffer layer provides perfectly ohmic contacts to n-type SiC – even to low-doped epitaxial layers without contact implantation. Contact resistances to highly doped samples are competitive with conventional annealed nickel (Ni) contacts; a direct comparison of Ni and graphene contacts on 4H-SiC resulted in an one order of magnitude reduction of the contact resistance in the case of graphene contacts. On highly doped 6H-SiC, a specific contact resistance as low as ρC = 5.9·10-6 Ωcm2 was found. This further improvement compared to 4H-SiC is assigned to better matching of work functions at the Schottky-like interface.
Electrical Characterization of Epitaxial Graphene Field-Effect Transistors with High-k Al2O3 Gate Dielectric Fabricated on SiC Substrates
Authors: Hopf Toby , Vassilevski Konstantin , Escobedo-Cousin Enrique , King Peter , Wright Nicholas G. , O'Neill Anthony , Horsfall Alton B. , Goss Jonathan , Wells George , Hunt Michael
Published: July 2015

Top-gated field-effect transistors have been created from bilayer epitaxial graphene samples that were grown on SiC substrates by a vacuum sublimation approach. A high-quality dielectric layer of Al2O3 was grown by atomic layer deposition to function as the gate oxide, with an e-beam evaporated seed layer utilized to promote uniform growth of Al2O3 over the graphene. Electrical characterization has been performed on these devices, and temperature-dependent measurements yielded a rise in the maximum transconductance and a significant shifting of the Dirac point as the operating temperature of the transistors was increased.
Realization and Characterization of Graphene on 4H-SiC for Tera-Hertz Transistors
Authors: Pezard Julien , Lhuillier Jeremy , El-Friach Zakarya , Soulière Véronique , Vilquin Bertrand , Rojo Romeo Pedro , Lazar Mihai
Published: July 2015

Few layers graphene has been grown on 4H-SiC. Since this material has outstanding electronic properties, we aimed fabricating graphene field-effect transistors on silicon carbide wafer. Growth of the graphene layers was made by e-beam sublimation of silicium under ultra high vacuum (UHV). These layers were patterned and used as channels of transistors with source and drain made of P+ SiC. The different technological steps were checked through Raman spectroscopy, Scanning Electron Microscopy (SEM), and electrical characterizations.
On the Formation of Graphene by Ge Intercalation of a 4H-SiC Surface
Authors: Chandran N. , Sall Mamour , Arvanitidis Jarvan , Christofilos Dimitris , Alassaad Kassem , Ferro Gabriel , Soulière Véronique , Polychroniadis Efstathios K.
Published: July 2015

The present communication focuses on the bilayer graphene formation on a Ge doped 4H-SiC surface. The 4H-SiC epilayer was grown by CVD with Germane (GeH4) as the dopant precursor. This easily leads to the formation of Ge islands as well as graphene on the 4H-SiC surface. The Ge island decorated surface was studied by Raman spectroscopy, XPS, and TEM. It was found that the bilayer graphene is free standing and that the native oxides act as a buffer layer on the surface, covering the Ge islands. The intensity variations of the Ge component in the XPS spectra indicate that Ge atoms can be buried in the SiC surface. The TEM analysis revealed that the graphene layers are in the form of flakes, which can also be rived vertically with the support of the Ge islands on SiC surface.
The Role of Aluminium in the Synthesis of Mesoporous 4H Silicon Carbide
Authors: Hvam Jeanette , Morgen Per , Warner Terence Edwin , Skou Eivind Morten , Wolff Thomas
Published: July 2015

Aluminium is found to play a key role in the process of forming a mechanically stable and highly porous and granular structure of 4H silicon carbide. The material is prepared by a high temperature reaction of the elemental constituents. The reactions are carried out under different background atmospheres, including nitrogen. Ternary carbides containing Al, Si and N, are formed in the process, and are believed to be responsible for the final outcome of the process, at the highest reaction temperatures, in the form of pure, well-connected grains of 4H-SiC forming a strong and rigid structure with high porosity. The Al containing compounds function as structural promoters for the 4H polytype recrystallization. This is expected - and partly shown - to take place through substitution with 4H-SiC and evaporation of all other constituents during the high temperature sintering step. When extruded into honeycomb structures prior to the sintering process this pure mesoporous SiC final product turns out to be ideal for a combined diesel particulate filter with support for catalysts in the pores.
Synthesis and Characterization of Al4SiC4: A “New” Wide Band Gap Semiconductor Material
Authors: Zevgitis Dimitrios , Chaix-Pluchery Odette , Doisneau Beatrice , Modreanu Mircea , La Manna Joseph , Sarigiannidou Eirini , Chaussende Didier
Published: July 2015

High temperature solution growth of Al4SiC4 single crystals was carried out from the melt of silicon and aluminium pieces in a graphite crucible used as carbon source (typically 1800°C under 1 bar of argon). The obtained crystals, in the mm scale, were then characterized by a variety of techniques including: Raman spectroscopy, transmission electron microscopy techniques, X-ray diffraction and UV-Vis-NIR spectroscopy. A good structural quality was revealed by TEM, ensuring a well resolved Raman spectrum. The UV-Vis transmission spectrum shows an optical gap located around 2-2.5 eV.
Silicon Growth on 3C-SiC(001)/Si(001): Pressure Influence and Thermal Effect
Authors: Khazaka Rami , Portail Marc , Vennéguès P. , Zielinski Marcin , Chassagne Thierry , Alquier Daniel , Michaud Jean François
Published: July 2015

We evaluate the influence of the growth parameters on the crystal quality of Si films grown by chemical vapor deposition on 3C-SiC(001)/Si (001) epilayers. It is shown that the pressure plays a major role on the final quality of the films, with two distinct growth regimes. The defects in the films were found to be antiphase boundaries and μ-twins. The influence of the growth parameters as well as the 3CSiC structural properties on these defects are discussed. The impact of a subsequent thermal annealing, under different gas environments, is also investigated and reveals some noticeable differences according to the gas environment used in the annealing process.
Innovations in SiC Backside Processing and Manufacturing for GaN/SiC Products
Authors: Wang Yao Hsien , Chen Chao Hao , Chang Yu Wei , Huang Shih Hui , Wei Yi Feng , Weng Ming Hung , Du Jhih Han , Wang Wei Chou , Cho I Te , Wohlmuth Walter
Published: July 2015

GaN High Electron Mobility Transistors (HEMTs) on SiC have gained remarkable attention as these devices are revolutionizing the power and radio frequency (RF) electronics markets. Although significant advances have been made in transistor technology innovations, innovations pertaining to the backside process technology have been noticeably few. This paper will address and focus on innovations in the backside processing of GaN on SiC devices. A series of innovations in backside processing enable through SiC and GaN via etch rates to exceed 1.5 micron/minute. Wafer dicing process innovations afforded a >4x improvement in sawing throughput and a >6x improvement in blade lifetime through the novel addition of ultrasonic power to a conventional sawing tool.
Microstructure and Temperature Dependent Electrical Characteristics of Ohmic Contacts to AlGaN/GaN Heterostructures
Authors: Greco Giuseppe , Iucolano Ferdinando , Roccaforte Fabrizio
Published: July 2015

AlGaN/GaN heterostructures are important materials for the fabrication of high power and high frequency devices. However, the mechanisms of Ohmic contacts formation on these systems are continuously under scientific debate. In this paper, a structural and electrical investigation of Ti/Al/Ni/Au Ohmic contacts to AlGaN/GaN heterostructures is reported. In particular, the behavior of Ti/Al/Ni/Au multilayers was monitored at different annealing temperatures. The contacts became Ohmic after annealing at 750°C and showed a decreasing temperature behavior of the specific contact resistance RC, described by a thermionic field emission mechanism. On the other hand, annealing at 850°C led to a further reduction of RC , with a slightly increasing dependence of RC on the measurement temperature (here regarded as a “metal-like” behavior). The microstructural analysis of the interfacial region allowed to explain the results with the formation of metallic intrusions contacting directly the two dimensional electron gas.
Thermal Stability and Mechanical Characteristics of Densified Ti3AlC2-Based Material
Authors: Prikhna Tatiana , Ostash Orest , Basyuk Tetyana , Ivasyshyn Andriy , Sverdun Volodymyr , Loshak Matvey , Dub Sergey , Podgurska Viktoriya , Moshchil Viktor , Cabioc’h Thierry , Chartier Patrick , Karpets Myroslav , Kovylaev Valeriy , Starostina Olexandra , Kozyrev Artem
Published: July 2015

The mechanical properties and temperature stability in air and hydrogen of the highly dense (ρ=4.27 g/cm3, porosity 1 %) material based on nanolaminated MAX phase Ti3AlC2 (89 % Ti3AlC2, 6 % TiC, 5 % Al2O3) manufactured by hot pressing (at 30 MPa) have been investigated. At room temperature the samplesexhibited microhardness HV = 4.6 GPa (at 5 N), hardness HV50 = 630 MPa (at 50 N ) and HRA=70 (at 600 N), Young modulus was 140 ± 29 GPa, fracture toughness K1C=10.2 MPa·m0.5compression strength 700 MPa and bending strength 500 MPa. After 1000 hours of exposition at 600 °C the oxide film (containing mainly Al2O3 and TiO2) formed on the surface and material demonstrated a higher oxidation resistance than chromium ferrite steels. Due to the surface oxidation the defects self-healing took place and the bending strength of the porous Ti3AlC2 (22% porosity) after exposition for 3 h at 600 oC in air slightly (for 3%) increased as compared to that at 20 oC. Besides, the porous Ti3AlC2 material resisted to high-temperature creep and after being kept in H2 at 600 °C for 3h its bending strength reduced by 5 %.
Temperature Dependence of Faraday Rotation in Microcavity 1D-MPCs Containing Magneto-Optical Layers with a Compensation Temperature
Authors: Berzhansky Vladimir N. , Karavainikov Andrey V. , Mikhailova Tatyana V. , Prokopov Anatoly R. , Shaposhnikov Alexander N. , Kharchenko M.F. , Lukienko I.M. , Miloslavskaya Olga V. , Kharchenko Yu.M.
Published: July 2015

The low-temperature behavior of optical and magneto-optical properties of microcavity 1D-MPCs with the Bi, Gd, Al-substituted YIG cavity layers of different compositions including compositions with a magnetic compensation temperatures were investigated. The optical transmittance and position of the resonant peaks in optical transmittance and the Faraday rotation spectra were found to be independent of temperature in all types of 1D-MPCs. The temperature dependence of changing the sign of Faraday rotation experienced the hysteresis with a value 8 K in one of two investigated MPCs with magnetic compensation temperature, while in the another MPC the hysteresis did not exceed 1 K. The possible origins of these properties are discussed.
Reorientation of Magnetization in Single Crystalline Yttrium Iron Garnet Film under Mechanical Strain
Authors: Sohatsky Vladimir , Kostuk Andriy , Savytsky Myhaylo
Published: July 2015

The results of the effect of mechanical strain on magnetic anisotropy, the direction of magnetization vector and domain structure of ferrite-garnet film, rigidly connected with the zirconium-titanium lead (PZT) piezoceramic plate are presented. It was established, that applied mechanical strain caused a 90°-reorientation of the magnetization vector from the initial perpendicular-to-plane into in-plane state. This strain acts similarly as applied magnetic field and when it applied simultaneously with the field, the piezovoltage necessary for reorientation is inversely proportional to magnetic field intensity. Such properties makes sandwich structures promising for use in spintronics and optoelectronics as a multicontrolled modulator of light.
High-Temperature Acoustical and Electrical Properties of LGS, LGT and CTGS Resonators
Authors: Suhak Yuriy , Schulz Michal , Richter Denny , Fritze Holger
Published: July 2015

Acoustic characteristics and electrical conductivity of CTGS, LGT and LGS bulk acoustic wave resonators operated at the fundamental mode in the temperature range of 20-1470°C are studied. It is shown that LGS and CTGS resonators can be excited piezoelectrically up to 1470 and 1270°C, respectively, which is close to their melting temperatures. The electrical conductivity of CTGS is found to be by at least two and three orders of magnitude lower than that of LGS and LGT, respectively, over the temperature range 400-1000°C. Measurements of temperature dependent electromechanical losses show, that they are at least by two orders of magnitude lower in CTGS comparing to that in LGS within the measured temperature range.
Features of Linear Defects Eddy Current Images Obtained with Use of Ferrite Garnet Films
Authors: Vishnevskii Victor G. , Berzhansky Vladimir N. , Lugovskoy Nazar L. , Prokopov Anatoliy R. , Pankov Fedor N.
Published: July 2015

The influence of most physical factors on the revelation ability of magneto-optic eddy current defectoscopy of linear defects in metallic objects is investigated. Uniaxial anisotropy multi-component Bi-substituted garnet film is used as the sensor element. The efficiency of visualization depends on frequency and amplitude of the inducer’s electric current and the biasing magnetic field. Optimal values of these parameters are obtained. It is shown that the alternative magnetic field exerts the most influence on the eddy current magneto-optic image.
Synthesis, Structure Refinement and Conductivity of Ln2-xCdxMoO6-x/2
Authors: Get`man E.I. , Chebyshev K.A. , Ardanova L.I. , Pasechnik L.V.
Published: July 2015

Substitution rare-earth elements for cadmium in the monoclinic compounds Ln2MoO6 (Ln – Gd, Ho) leads to the formation of fluorite-related cubic structure. Series Ln2xCdxMoO6x/2 was investigated by XRD (with structure refinement), scanning electron microscopy, FTIR-spectroscopy and conductivity measurements.
First-Principles Study of Electronic Structure of Cubic Perovskite-Like Fluorides
Authors: Syrotyuk Stepan , Shved Vira
Published: July 2015

The electronic density of states of cubic perovskite-like fluorides has been evaluated by means of the projector augmented waves (PAW) within the local density approximation (LDA). For the first time the improved electronic energy bands have been calculated using the GW approximation. Ground-state and quasiparticle calculations have been done with the ABINIT code. Combined analysis of the densities of electronic states and obtained electron energy spectra makes it possible to draw conclusions regarding the possibility of the phenomenon of core-valence luminescence in the considered crystals.
Properties and Potential Applications of Ferromagnetic Nanostructures in Medicine and Microwave Engineering
Authors: Belous Anatolii G. , Solovyova E.D. , Solopan S.O. , Yelenich O.V. , Bubnovskaya L.N. , Osinsky S.P.
Published: July 2015

Three types of ferromagnetic nanostructures based on barium hexaferrite (BaFe12O19), lanthanum-strontium manganites with perovskite structure ((La,Sr)MnO3) and materials with spinel structure (AFe2O4, A = Ni, Zn, Co, Mn, Fe) have been synthesized by precipitation from aqueous and nonaqueous solutions, by the sol-gel method and from microemulsions. Magnetic properties of the synthesized nanoparticles and films have been investigated. It was shown that the obtained nanoparticles exhibit superparamagnetic properties. It has been found that the synthesized nanoparticles have promise in hyperthermia of cancer cells. It has been shown that the films based on barium hexaferrite can have promise in the creation of nonlinear resonant microwave elements on the basis of high-Q dielectric resonators and ferromagnetic films.
Mechanical and Structural Characterization of Rapidly Solidified Al-Fe-Mg Alloys
Authors: Kula Anna , Blaz Ludwik , Kusper Piotr , Sugamata Makoto
Published: July 2015

Series of experiments on a series of Al-Fe-Mg alloys were performed to determine the effect of rapid solidification (RS) on the material strengthening, which result from the refining of thegrain size and intermetallic compound. Additionally, an enhancement of the material strengthening due to magnesium addition was also observed. Manufacture of RS Al-Fe-Mg alloys combined a spraydeposition of the molten alloy on the rotating water-cooled copper roll and plastic consolidation bymeans of powders pressing and hot extrusion methods. The results suggest that the rapid solidification provides an effective method of microstructure refinement and, in combination with solid solutionhardening due to Mg, leads to significant improvement of mechanical properties of Al-Fe-Mg based alloys.
The Microstructure of Weld Overlay Ni-Base Alloy Deposited on Carbon Steel by CMT Method
Authors: Solecka Monika , Petrzak Paweł , Radziszewska Agnieszka
Published: July 2015

Ni-base alloys, like Inconel 625, exhibit a high temperature corrosion and oxidation resistance. For this reason, these alloys are typically used as a one of the most important coating material and can be applied in a different environments and elements of devices having various applications. In this work, Inconel 625 was deposited onto a carbon steel P235GH by Cold Metal Transfer method. Due to the segregation of Ni, Cr, Nb and Mo elements the Inconel 625 weld overlays cladded on boiler pipes P235GH obtained the dendritic structure, with the formation of a second phases at the end of solidification. The presence of γ (with high dislocation density), the Laves and (Nb,Ti)C phases was revealed by means of TEM examinations. The multipoint EDS analysis confirmed the presence of low Fe concentration in the Inconel 625 alloy coatings. The concentration profiles of Ni, Cr, Mo and Nb performed across the dendritic structure showed segregation of these elements.
Effect of Hydrogen on the Corrosion of Rare Earth-Containing Magnesium Alloys in Sodium Sulfate Solution
Authors: Mościcki Adrian , Chmiela Bartosz , Sozańska Maria
Published: July 2015

Modern magnesium alloys containing rare earth (RE) elements from the Mg-Y-RE-Zr and Mg-Al-RE systems are characterized by low density and good mechanical properties. Therefore, these alloys are used in the automotive and aerospace industries. However, magnesium alloys offer insufficient corrosion resistance in environments containing electrolyte solutions. Hydrogen is themain corrosive factor appearing during chemical reactions between magnesium and water in anelectrolyte solution. The results showed that when samples were immersed in 0.1M sodium sulfate solution, some cracks were observed inside the Al11RE3 and Al8CeMn4 intermetallic phases. Phase identification was performed by electron backscatter diffraction (EBSD) analysis. The microstructure of the alloys before and after corrosion was observed using a scanning electron microscope (SEM).
Shape, Size and Distribution of Metal Particles Embedded in a Ceramic Matrix
Authors: Konopka Katarzyna
Published: July 2015

The presented paper is a review of own work done on two systems of composites, Al2O3‑Ni and Al2O3-Fe. The previous own results of research into shape, size and distribution of the metal particles and spinel phase embedded in a ceramic matrix are referred to and new ones are presented. Metal particles as well as spinel can be distributed uniformly in a ceramic matrix or can form graded structures. Most often there are agglomerates of metal or spinel particles rather than separated particles embedded in ceramic grains. In composites the growing spinel forms a thick oval layer around a metal particle, however, separate spinel areas embedded in a ceramic matrix are noticed, too. Also, the characteristic “doughnut” shape of spinel is found. Since the metal and spinel phase influence the mechanical properties, the required properties of ceramic-metal composites can be tailored by changing the size, shape and distribution of the phases.
Electron Microscopy Investigation of Cast Aluminium Alloy after Laser Feeding with Ceramic Powder
Authors: Labisz Krzysztof , Tanski Tomasz , Konieczny Jarosław , Pawlyta Mirosława , Jonda Ewa
Published: July 2015

This paper presents the results of an investigation using transmission electron microscopy concerning the structure of AlSi7Cu2 cast aluminium alloy after alloying and remelting with a high power diode laser (HPDL). In particular, the changes in the particle/precipitation type, size and shape were determined, concerning especially the SiC and TiC particles added to the initial material. The aim of this work was also to present the laser treatment technology which will be used for further alloying and remelting with ceramic powders – especially carbides and oxides. The innovatory arrangement of this investigation is based on the mixing of two different powders, which were fed simultaneously to the laser-treated aluminium surface. The overview focuses on the laser power required to achieve good layer hardness to prevent hot work tool steel from losing its work stability and to make the tool surface more resistant to action in external conditions.
Recent Advances in Synthesis, Properties and Applications of Magnetic Oxide Nanomaterials
Authors: Tripathi S.K. , Kaur Ramneek , Bharti Shivani , Gawri Isha , Kaur Jagdish
Published: July 2015

Oxide nanomaterials are in great demand due to their unique physical, chemical and structural properties. The nanostructured materials with desired magnetic properties are the future of power electronics. Unique magnetic properties and excellent biocompatibility of these materials found applications in pharmaceutical field also. For these applications, the synthesis of magnetic oxide nanomaterials with required properties is highly desirable. Till now, various techniques have been evolved for the synthesis of oxide nanomaterials with full control over their shape, size, morphology and magnetic properties. In nanoscale, the magnetic properties are totally different from their bulk counterparts. In this range, each nanoparticle acts as a single magnetic domain and shows fast response to applied magnetic field. This review article discusses the synthesis techniques, properties and the applications of magnetic oxide nanomaterials. Various characterization techniques for magnetic materials have been discussed along with the literature of iron oxide, nickel oxide, and cobalt oxide nanomaterials. The challenges for further development of these materials have also been presented to broaden their rapidly emerging applications.
Recent Advances in Application of Landau-Ginzburg Theory for Ferroelectric Superlattices
Authors: Lim Kok Geng , Chew Khian Hooi , Ong Lye Hock , Iwata Makoto
Published: July 2015

Ferroelectric superlattices with polarization perpendicular to the surface or interface are studied within the framework of the Landau-Ginzburg theory. An interface energy is introduced in the free energy to describe the effect of mixing and local polarization coupling at interface. Internal electric field is considered in the model. For superlattices grown on substrate, the influence of substrate on the properties of ferroelectric superlattices is required. This brief review is a sequel to the previous review article [1], which summarizes the recent development in Landau-Ginzburg theory developed for studying ferroelectric superlattices over approximately the last three years.
Ferroelectric Materials for High Temperature Piezoelectric Applications
Authors: De Udayan , Sahu Kriti Ranjan , De Abhijit
Published: July 2015

Electronic control and operation in almost all advanced devices or machines involve use of various sensors and actuators, many of which are based on piezoelectric (PE) effect. Ferroelectric (FE) materials forming a sub-group of piezoelectric materials have additional applications. Subject to success in materials and related developments, PE and FE devices perform competitively with alternative devices but at lower cost in most cases. There is increasing commercial and technical interest for PE actuators (ranging from electronic muscles, fuel injectors and inkjet printers to various vibrators), PE sensors (pressure and other sensors and motion detection to energy recovery), and ultrasonic imaging devices. PE to non-PE transition temperature (Curie temperature for FE PE materials) and piezoelectric coefficients together decide the choice of the right material for any particular application. Since most of these applications, including medical ultrasonic imaging, are done at or near room temperature, low Curie temperature (but otherwise attractive) piezoelectric materials, based on barium titanate (BT), lead zirconate titanate (PZT) and relaxor ferroelectric ceramics, have served us well. However, a few important applications, in automobile and rocket exhausts, in some engines and gadgets, and inside high pressure molten metal in nuclear Fast Breeder Reactors (FBRs) involve high temperatures (HTs), higher than or nearing the Curie temperature of even PZT. These applications including FBRs, generating nuclear fuel and power, demand development of high temperature piezoelectric materials. FBRs can close the nuclear fuel cycle by partially using the nuclear waste (containing U-238) and thus minimize waste disposal problem. That makes nuclear energy a better green energy. Working on Th-232 from monazite sand, FBRs can breed Th-233, a nuclear fuel, with simultaneous generation of electricity. Ranging and imaging of nuclear fuel rods and control rods through the liquid metal coolant in FBRs, especially during insertion and withdrawal, help correct positioning of the rods to avoid any misalignment and possible nuclear accident. This “viewing” through the optically opaque liquid metal or alloy coolant, is possible by ultrasonic imaging of the rods using HT PE ultrasonic-generators and-detectors, an active area of research. Lithium niobate with T(Curie) > 1000°C and orthorhombic PbNb2O6with T(Curie) > 570°C are two of many HT PE materials under development or in trial runs. In the present work, world-wide R & D on HT piezoelectric materials has been reviewed after an outline of the basics.
Research at the Bedside: It Makes A Difference
Authors: Bridges Elizabeth J.
Published: July 2015

Research at the bedside makes a difference for our patients, and also for our nurses. However, it is now time to broaden our focus from research on interventions or events at a narrow point in time to research that addresses care across the continuum. This continuum may start at the point of injury, such as the battlefield through en route care delivered during the 8000-mile journey home for our wounded warriors, or for critically ill patients as they move between the emergency department, operating room, and intensive care unit. This focus also requires researchers to consider “care within context,” that is, research- and evidence-based practice tailored to the unique conditions of the care environment. Beyond conducting research and developing new knowledge is the challenge of translating evidence into practice. A culture of inquiry is a critical element in the successful translation of evidence into practice. In a culture of inquiry, nurses are encouraged to question and evaluate their practice, provide evidence-based care, and actively participate in and lead clinical inquiry. This article draws from a program of applied clinical research reflecting care across the continuum within both military and civilian health care settings and discusses how the application of these research findings and the advancement of a culture of inquiry make a difference for both patients and nurses.
Evolution in the use of musculoskeletal ultrasonography in a Rheumatology Unit over 14 years
Authors: Gil Barato S. , De Miguel Mendieta E. , Martin-Mola E.
Published: July 2015

The aim of this article is to evaluate the use of musculoskeletal ultrasound in the daily clinical practice of a rheumatology unit. We conducted a descriptive retrospective analysis of the ultrasound examinations performed during 2011 and a comparison of these examinations with those performed between 1998 and 2003 and between 2007 and 2008. A total of 712 ultrasound examinations performed in 2011 were reviewed. Out of the total, examinations of individual areas of the body represented 11.6% versus 45.9% of the examinations made between 2007 and 2008 and 100% of those performed before 2003. The remaining 88.4% of ultrasound examinations performed in 2011 were intended to investigate inflammation in 25.8%, differential diagnosis of arthralgia in 17.1%, enthesis in 12.6% and temporal arteries in 17.3%, and to conduct ultrasound-guided procedures in 10.6% and study microcrystalline pathologies in 4.7%. In our unit, ultrasonography is evolving from being a mere investigation of individual areas of the body to becoming a clinical information tool, which contributes to the diagnosis and monitoring of the disease activity in the patient as a whole.
Cytomegalovirus ileocolitis in a rheumatoid arthritis patient: case report and literature review
Authors: Dag M. S. , Turkbeyler I. H. , Ozturk Z. A. , Kısacık B. , Tutar E. , Kadayıfçı A.
Published: July 2015

Rheumatoid arthritis (RA) is an autoimmune, systemic, chronic, inflammatory disease generally treated with various immunosuppressive drugs. Cytomegalovirus (CMV) is an opportunistic, viral infection that is commonly seen in immunosuppressed patients. A sixty-four-year old female diagnosed with RA and treated with immunosuppressive agents was admitted to our rheumatology outpatient service with complaints of diarrhea and abdominal pain, which had lasted longer than four weeks. The patient’s colonoscopy revealed inflamed and ulcerated areas in the colon and in the terminal ileum. A biopsy showed intra-nuclear inclusion particles consistent with CMV. We started an oral valganciclovir therapy in this serum-CMV-polymerase chain reactionpositive patient. The concomitant use of immunosuppressive agents and anti-viral drugs eased the patient’s complaints, and the endoscopic picture improved. Consequently, cytomegalovirus ileocolitis in immunosuppressed patients admitted with severe diarrhea must be considered in the differential diagnosis.
‘If those to whom the W/word of God came were called gods ...’– Logos, wisdom and prophecy, and John 10:22–30
Authors: Draper Jonathan A.
Published: July 2015

Jesus’ quotation of Psalm 82:6, ‘I said, You are gods’, a riposte to the accusation that he had blasphemed by making himself equal to God, has attracted considerable attention. The latest suggestion by Jerome H. Neyrey rightly insists that any solution to the problem should take account of the internal logic of the Psalm and argues that it derives from or prefigures a rabbinic Midrash on the Psalm which refers it to the restoration of the immortality lost by Adam to Israel at the giving of the Torah on Sinai. This immortality was then lost again because of the sin of the golden calf. Whilst agreeing that the Psalm is interpreted in the context of the giving of the Torah on Sinai, this article argues that its reference is directed towards Moses on Sinai rather than Israel in general. This accords with the interpretation of Philo and Josephus and other sources much earlier than the Mekkilta de Rabbi Ishmael that Moses is rightly called a god and is assumed to heaven in glory without dying. Rather than deny this attribution of divine features to Moses due to his reception of the Torah on Sinai, John argues that the Torah was received from the hands of Jesus as the Logos. Therefore, Moses’s derivative divine features simply confirm the true divinity of the Logos as the expression of the Father. Moses could be called a god because he knew Jesus as Logos and wrote about him (5:45–5:47), but he sinned and died like any mortal. The corollary is that Moses and his disciples lost their status and died like any mortal, whilst the disciples of Jesus who are ‘taught by God’ and believe in the Incarnate Logos (6:45), have not only seen the glory denied to Moses but are born from above to become divinised as tekna theou (1:12) and do not die.
Exploring the characteristics of capable healthcare professionals
Authors: Rowe Michael
Published: July 2015

Background: In order to negotiate complex clinical environments successfully, healthcare professionals must be more than competent – they must demonstrate an ability to adapt to dynamic situations and continually improve performance. However, emphasis on knowledge and skills alone may ignore opportunities for professional development that enables students to become practitioners.Objectives: The aim of this study was to ascertain what clinical experts believe are the essential characteristics of capable healthcare professionals that go beyond academic and technical competencies.Method: This study used a nominal group technique (NGT) to gather data from a panel of South African and international clinical experts, using open-ended questions and qualitative data analysis to determine emergent themes. The NGT is an interpretive research method that can be used to explore poorly defined topics, in this case to develop an understanding of the characteristics of health professionals that go beyond knowledge and technical skill.Results: Panel members highlighted the importance of knowledge and skills for competent practice, but also explored other aspects of the learning process as part of developing professional identity. These included self-evaluation as part of professional development,building relationships with patients, and the importance of acknowledging students’emotional responses to the clinical environment. Panel members also discussed the challenge of inappropriate role-models in the clinical context, who may have a negative influence on the development of professional practice.Conclusion: By including the concept of capability alongside competency in undergraduate healthcare curricula clinical educators can help students develop a sense of being that emphasises professional growth alongside knowledge and technical skills.
Kapālabhāti as a panacea to control aggressive behavior in adolescents
Authors: Sharma Vikas Kumar , Sahare Pragya
Published: July 2015

Background:

Aggression in adolescence is a key point of focus for psychologists, educationists, parents, and teachers. On the other hand, interdisciplinary researches with special reference to yoga and psychology are growing rapidly in this era of applied science. Despite rapidly growing scientific literature on yoga and its application, there has been no study conducted to determine whether Kapālabhāti (a yogic practice) affects the aggression level in adolescents.

Aims:

The current study aimed at exploring the effect of Kapālabhāti on the aggression level of adolescents.

Methods:

A sample consisting of 40 intermediate and undergraduate students from Gayatri Vidyapeeth and Dev Sanskriti Vishwavidyalaya, Haridwar, Uttarakhand, respectively, was taken. The entire sample belonged to the age group of 15-20 years. Kapālabhāti practice was given to each and every subject of the group for a period of 30 days regularly. In this research, pre-post single-group design has been applied. Participants were given a questionnaire named as "aggression scale" (A-scale) which was developed by Pal and Naqvi (1983) for measurement of aggression score.

Statistical Analysis Used:

Paired sample t-test and eta-squared statistics have been used for comparing pre- and post-mean scores and computing the magnitude of the effect of intervention, respectively.

Results:

There was a statistically significant decrease in the aggression score from pre-test (M = 63.85, SD = 21.75) to post-test (M = 49.95, SD = 14.53), t (39) = 8.42, P < 0.01 (two-tailed). The mean decrease in aggression score was 13.9 with a 99% confidence interval. The eta-squared statistics was 0.64, which indicates large effect of the intervention on aggression.

Conclusions:

The findings revealed that the practice of Kapālabhāti is highly effective in reducing the aggression level in participants, which was significant at 0.01 level of significance.
Emerging need for meditation practice in the community
Authors: Kumar Ganesh S
Published: July 2015

Meditation practice is one of the most important health factors that need attention, especially in developing countries including India. This is keeping in view of the recent increase in the trend of non-communicable diseases and their risk factors in the population. The need of the hour is to address the need for practice of meditation at a community level to improve the populace health. This article explains the importance of meditation, its awareness generation, and the factors required to improve its practice in the community.
Non-Hodgkin Lymphoma of the Stomach in a Patient Treated with Natalizumab
Authors: Law Jennie Y. , Kim Dong W. , Sturgis Ariel , Naina Harris V.
Published: July 2015

A 61-year-old man with relapsing-remitting multiple sclerosis developed extranodal large B-cell lymphoma of the stomach following monthly natalizumab infusions for 6 years. Development of lymphoproliferative disorders increases with chronic use of immunosuppression. Cases of primary central nervous system lymphoma as well as one case of peripheral T-cell lymphoma have previously been reported with natalizumab use. Given the absence of a known association between multiple sclerosis and extranodal presentations of diffuse large B-cell lymphoma, a causal association with natalizumab administration cannot be excluded.