bluuebunny/crossref_metadata_2025 huggingface dataset:
GEOPHYSICS BRIGHT SPOTS
Authors: Mahrer Ken
Published: April 2011

Welcome, friend, to another edition of Bright Spots, your friendly GEOPHYSICS spotlighter. Our last column came to you via choices from both the Associate Editors of GEOPHYSICS and me. This month's choices are only mine. There are 37 articles in the March–April issue of GEOPHYSICS, and I spotlight six. I hope my short summaries motivate you to their sources and others equally worthy, but not on my radar. As always, GEOPHYSICS is worth your effort. Remember, learning is not just a selfish effort; it includes absorbing the sunshine of others. Thanks again for stopping by.
ATV magnetometer systems for efficient ground magnetic surveying
Authors: Athens Noah D. , Glen Jonathan M. G. , Morin Robert L. , Klemperer Simon L.
Published: April 2011

Ground magnetic data contain information, not pre-sent in aeromagnetic data, which may be useful for precisely mapping near-surface faults and contacts, as well as constraining or aiding interpretation of other geophysical methods. However, collecting ground magnetic data on foot is labor-intensive and is therefore limited to small surveys. In this article, we present two newly developed all-terrain vehicle (ATV) magnetometer systems that significantly expand the survey area that is possible in a ground magnetic survey without greatly reducing the quality of data.
Differential Recruitment of Nuclear Coregulators Directs the Isoform-Dependent Action of Mutant Thyroid Hormone Receptors
Authors: Fozzatti Laura , Lu Changxue , Kim Dong-Wook , Cheng Sheue-yann
Published: April 2011

Studies using mice deficient in thyroid hormone receptors (TR) indicate that the two TR isoforms, TRα1 and TRβ1, in addition to mediating overlapping biological activities of the thyroid hormone, T3, also mediate distinct functions. Mice harboring an identical dominant negative mutation (denoted PV) at the C terminus of TRα1 (Thra1PV mice) or β1 (ThrbPV mice) also exhibit distinct phenotypes. These knockin mutant mice provide an opportunity to understand the molecular basis of isoform-dependent functions in vivo. Here we tested the hypothesis that the distinct functions of TR mutant isoforms are directed by a subset of nuclear regulatory proteins. Tandem-affinity chromatography of HeLa nuclear extracts showed that distinct 33 nuclear proteins including nuclear receptor corepressor (NCoR1) and six other proteins preferentially associated with TRα1PV or TRβ1PV, respectively. These results indicate that recruitment of nuclear regulatory proteins by TR mutants is subtype dependent. The involvement of NCoR1 in mediating the distinct liver phenotype of Thra1PV and ThrbPV mice was further explored. NCoR1 preferentially interacted with TRα1PV rather than with TRβ1PV. NCoR1 was recruited more avidly to the thyroid hormone response element-bound TRα1PV than to TRβ1PV in the promoter of the CCAAT/enhancer-binding protein α gene to repress its expression in the liver of Thra1PV mice, but not in ThrbPV mice. This preferential recruitment of NCoR1 by mutant isoforms could contribute, at least in part, to the distinct liver lipid phenotype of these mutant mice. The present study highlights a novel mechanism by which TR isoforms direct their selective functions via preferential recruitment of a subset of nuclear coregulatory proteins.
Variants in hepatocyte nuclear factor 4α gene promoter region and type 2 diabetes risk in Chinese
Authors: Chen Zhuo , Zhang Di , Liu Yun , Zhou Daizhan , Zhao Teng , Yang Yifeng , He Lin , Xu He
Published: April 2011

As a key regulator of insulin secretion and metabolism of glucose, cholesterol and fatty acid, hepatocyte nuclear factor 4 α (HNF4A) was suggested as a candidate gene for type 2 diabetes (T2D); however, no association study between HNF4A and T2D in the Chinese population has been conducted before. To address this issue, we evaluated the impact of the HNF4A variants (rs1884614 and rs2425637) on T2D and metabolic traits in 1912 unrelated patients and 2041 control subjects in the Chinese Han population. Our results suggested that no individual single nucleotide polymorphisms of HNF4A was significantly associated with T2D at either allele or genotype level. However, rs2425637 in the promoter region of HNF4A was found to have an effect on total cholesterol and high-density lipoprotein before multiple testing correction. To summarize, our investigation did not confirm the effects of HNF4A variants (rs1884614 and rs2425637) on T2D risk, but found that the risk HNF4A contributed to T2D might be population specific.
Cell line models for differentiation: preadipocytes and adipocytes
Authors: Poulos Sylvia P , Dodson Michael V , Hausman Gary J
Published: April 2011

In vitro models have been invaluable in determining the mechanisms involved in adipocyte proliferation, differentiation, adipokine secretion and gene/protein expression. The cells presently available for research purposes all have unique advantages and disadvantages that one should be aware of when selecting cells. Established cell lines, such as 3T3-L1 cells, are easier and less costly to use than freshly isolated cells, even though freshly isolated cells allow for various comparisons such as the in vitro evaluation of different in vivo conditions that may not be possible using cell lines. Moreover, stem cells, transdifferentiated cells or dedifferentiated cells are relatively new cell models being evaluated for the study of adipocyte regulation and physiology. The focus of this brief review is to highlight similarities and differences in adipocyte models to aid in appropriate model selection and data interpretation for successful advancement of our understanding of adipocyte biology.
Core Routing on Dynamic Time-Dependent Road Networks
Authors: Delling Daniel , Nannicini Giacomo
Published: April 2011

Route planning in large-scale time-dependent road networks is an important practical application of the shortest-path problem that greatly benefits from speedup techniques. In this paper, we extend a two-level hierarchical approach for point-to-point shortest-path computations to the time-dependent case. This method, also known as core routing in the literature for static graphs, consists of the selection of a small subnetwork where most of the computations can be carried out, thus reducing the search space. We combine this approach with bidirectional goal-directed search to obtain an algorithm capable of finding shortest paths in a matter of milliseconds on continental-sized networks. Moreover, we tackle the dynamic scenario where the piecewise linear functions that we use to model time-dependent arc costs are not fixed but can have their coefficients updated requiring only a small computational effort.
The Impact of Economic Contractions on the Effectiveness of R&D and Advertising: Evidence from U.S. Companies Spanning Three Decades
Authors: Steenkamp Jan-Benedict E. M. , Fang Eric (Er)
Published: April 2011

The critical role of research and development (R&D) and advertising in the marketing strategy of the firm is well established. This paper conceptually and empirically examines why and how much the effectiveness of these two marketing instruments differs between times of economic expansions versus periods of economic contractions—and whether these results depend on the cyclicality of the industry in question. We consider a key marketing metric (market share) and a key financial metric (firm profit). Our empirical setting is 1,175 U.S. firms across a time period spanning over three decades. We find that R&D and advertising contribute to firm performance but that their effectiveness is not constant across the business cycle. Increasing advertising share in contractions has a stronger effect on profit and market share than increasing advertising share in expansions. Likewise, investments in R&D in contractions lead to higher gains in market share and profit than R&D investments in expansions, albeit only in subsequent years. If in contractions the firm faces tight budget constraints and has to choose between either maintaining R&D or advertising, our simulation results show that maintaining R&D is associated with better company performance. We find that advertising effectiveness, in general, and in contractions, in particular, is systematically moderated by the degree of cyclicality of the industry in which the firm operates. In relatively stable industries, advertising effects are small or even nonsignificant, and they do not go beyond the year the firm advertises. However, in highly cyclical industries, advertising effects are long-lasting, its total effect being 50% larger (market share) and 200% larger (profits) than in industries of average cyclicality. The effect of industry cyclicality on advertising effectiveness is especially pronounced in contractions. Collectively, these findings provide valuable and actionable insights into how firms should respond to contractions in order to grow profits and market share.
The case for removing the subchondral bone plate in preparation of the acetabulum
Authors: Gilbody J.
Published: April 2011

Aseptic loosening of the acetabular component continues to be the most common indication for revision of total hip replacements in younger patients. Early in the evolution of the cemented hip, arthroplasty surgeons switched from removal to retention of the acetabular subchondral bone plate, theorising that unfavourable mechanical forces were the cause of loosening at the bone-cement interface.

It is now known that the cause of aseptic loosening is probably biological rather than mechanical and removing the subchondral bone plate may enhance biological fixation of cement to bone. With this in mind, perhaps it is time to revive removal of the subchondral bone as a standard part of acetabular preparation.
Professional Values in Knowledge Organisations: The Case of Police Districts
Authors: Glomseth Rune , Gottschalk Petter , Hole Åse Storhaug
Published: April 2011

The purpose of this paper is to present results from a survey of police managers in Norway on occupational culture that relate to characteristics of knowledge organisations. A questionnaire was developed and administered among police managers in two police districts in Norway. A total of 21 police personnel values for occupational culture were applied in this research. All of them represent cultural dimensions of potential importance to law enforcement performance. Significant correlations were found between knowledge organisation and change rather than tradition, freedom rather than control, balance between work and private life, equality and empowerment rather than hierarchy, and openness rather than closed culture. Furthermore, a knowledge organisation is also a learning organisation.
Melt corrosion of refractories in the nonferrous industry and the electric arc furnace: A thermochemical approach
Authors: Reiter Viktoria , Harmuth Harald
Published: April 2011

A thermochemical approach was implemented to study the dissolution mechanisms of a wide range of refractory oxides and silicates in slags of the nonferrous metals industry and electric arc furnaces. First of all, the slags have been characterized regarding their working range, phase assemblage, and melting behavior. Subsequently, the interactions of different combinations of refractory and slag have been examined, and emphasis has been placed on the determination of possible reaction products formed during dissolution and the solubilities of the refractory oxides and silicates in various slags. Direct dissolution, decisive in the case of high corrosion rates, as well as indirect dissolution have been described. Varying operation conditions (e.g., temperature, atmosphere) have been incorporated into the investigations. In addition to the thermochemical calculations, the solubility of magnesia in fayalite slags has been determined experimentally with the quenching method and the calculated results have been compared to published corrosion studies of other authors. These studies revealed that thermochemical calculations are a suitable tool to examine melt corrosion. The thermochemical approach provides information that can be incorporated into product development and in the operation mode, giving a proper choice of process conditions.
Vibration Based Damage Identification Using Burg's Algorithm and Shewhart Control Charts
Authors: Rao Putti Srinivasa , Ratnam Ch.
Published: April 2011

This paper proposes a methodology for the health monitoring of structures capable of identifying the damage at the earliest possible stage using the acceleration time response data obtained from piezoelectric accelerometers. In this, a unique combination of databased models to extract the damage sensitive features and Shewhart control charts to monitor the variations of the selected damage sensitive features are presented. The applicability of the proposed method is tested with the welded structure model by fixing it to the multi axes electro dynamic vibration shaker. In this, damage will be defined as a crack through the thickness of the weld and damage was introduced into the structure by cutting a slot in the weld using electric discharge machining. The acceleration time response data from the test structure are measured for five damage levels. Damage sensitive features are extracted by fitting a time prediction databased model called an Auto Regressive model to the measured acceleration time response data obtained from the undamaged structure. Then, the residual errors are calculated at each time step. To monitor the variation of mean and standard deviation of the extracted damage sensitive features, X-bar and S control charts are used. It is found that X-bar and S charts are capable of identifying the presence of damage for different damage levels considered in this work.
Interleukin 10 deficiency attenuates induction of anti-TSH receptor antibodies and hyperthyroidism in a mouse Graves' model
Authors: Ueki Ikuko , Abiru Norio , Kawagoe Kentaro , Nagayama Yuji
Published: April 2011

Experimental Graves'-like hyperthyroidism can be induced in susceptible mouse strains by repetitive immunizations with recombinant adenovirus expressing the human full-length TSH receptor (TSHR) or its A-subunit. Previous studies have shown that splenocytes from immunized mice produce interferon (IFN)-γ and interleukin (IL) 10 in response to antigen stimulation in an in vitro T cell recall assay. Although IFN-γ is now well known to be essential for disease induction, the role(s) played by IL10 are unknown. Therefore, this study was conducted to clarify the significance of endogenous IL10 in the pathogenesis of experimental Graves' disease using IL10 deficient (IL10−/−) mice. Our results show that T cell response was augmented when estimated by their antigen-specific secretion of the key cytokine IFN-γ, but B cell function was dampened, that is, anti-TSHR antibody titers were decreased in IL10−/− mice, resulting in a lower incidence of Graves' hyperthyroidism (54% in IL10+/+ vs 25% in IL10−/−). Thus, in addition to IFN-γ, these data clarified the role of IL10 for optimizing anti-TSHR antibody induction and eliciting Graves' hyperthyroidism in our Graves' mouse model.
Fabrication of Semi-transparent Resistive Random Access memory and Its Characteristics of Nonvolatile Resistive Switching
Authors: Seo Jung Won , Baik Seung Jae , Kang Sang Jung , Lim Koeng Su
Published: April 2011

This report covers the resistive switching characteristics of cross-bar type semi-transparent (or see-through) resistive random access memory (RRAM) devices based on ZnO. In order to evaluate the transmittance of the devices, we designed the memory array with various electrode sizes and spaces between the electrodes. To prevent read disturbance problems due to sneak currents, we employed a metal oxide based p-NiO/n-ZnO diode structure, which exhibited good rectifying characteristics and high forward current density. Based on these results, we found that the combined metal oxide diode/RRAM device could be promising candidate with suppressed read disturbances of cross-bar type ZnO RRAM device.
Preparation of the CrO2 thin films using a Cr8O21 precursor
Authors: Muraoka Y. , Iwai K. , Yoshida S. , Wakita T. , Hirai M. , Yokoya T. , Kato Y. , Muro T. , Tamenori Y.
Published: April 2011

We have prepared a CrO2 thin film by chemical vapor deposition from a Cr8O21 precursor and studied the bulk and surface physical properties. The CrO2 thin film is grown on TiO2(100) substrate by heating precursor and TiO2 (100) substrate together in a sealed quartz tube. The prepared film is found from x-ray diffraction analysis to be an (100)-oriented single phase. The magnetization and resistivity measurements indicate that the film is a ferromagnetic metal with a Curie temperature of about 400 K. Cr 3s core-level and valence band photoelectron spectroscopy spectra reveal the presence of a metallic CrO2 in the surface region of the film. Our work indicates that preparation from a Cr8O21 precursor in a closed system is promising for obtaining a CrO2 thin film with the metallic surface.
Modeling Radiation-Induced Alteration of the Network Structure of Alkali Borosilicate High-level Waste Glass
Authors: Dewan Leslie , Hobbs Linn W. , Delaye Jean-Marc
Published: April 2011

High-level nuclear waste glasses are subject to radiation-induced degradation over very long time scales. In such glasses, bond-breakage and atom displacements occur by both radiolysis (principally from energetic beta-decay electrons) and ballistic mechanisms involving collision cascades initiated by energetic fission nuclei and recoil of alpha-emitting actinide nuclei [1]. This study investigates collision-cascade-induced alteration of the glass network in a simplified sodium borosilicate model nuclear waste glass, using molecular dynamics (MD) codes and efficient topological assessment algorithms. Collision cascades were initiated ballistically (4 keV initial kinetic energy, dissipated elastically) and carried out using MD codes incorporating both two-body Buckingham and three-body Stillinger-Weber potentials verified in the GULP atomistic simulation package. Network topologies of the initial and resulting altered glass structures were determined by enumerating the primitive-ring-based local cluster atom complement at each atom site. The topological description is seen to provide a revealing assessment of network structural changes in the simulated radiation environment that can be potentially related to observable macroscopic changes, such as swelling, viscosity changes, and radiation-induced devitrification.
The Effect of Grain-Boundary and Matrix Precipitates on High Temperature Strength in Fe3Al Based Alloys
Authors: Makihara Ryo , Kobayashi Satoru , Takasugi Takayuki
Published: April 2011

The effect of grain boundary (GB) and matrix precipitates on high temperature strength was investigated in Fe3Al base alloys containing Cr, Mo and C. Tensile tests were conducted at 600°C for three types of microstructures consisting of: (I) film-like κ phase precipitates covering GBs and fine M2C particles in the matrix, (II) only fine M2C particles in the matrix and (III) no second-phase particles in the matrix. It was found that κ films on GBs are more than twice as effective as finely dispersed M2C particles for improving the proof stress.
The Formation of A2/L21 Microstructure in Fe-Al-Ti-Cr Alloys
Authors: Hotta Suguru , Kobayashi Satoru , Takasugi Takayuki
Published: April 2011

The composition areas of the A2/L21 two-phase field in the Fe-Al-Ti-Cr quaternary system at 800 ºC and 700 ºC were investigated using a diffusion-multiple (DM) technique for which Fe-30Al-7Ti, Fe-30Cr-7Ti and Fe-7Ti alloys were diffusion-coupled and heat-treated. The A2/L21 two-phase field was found to expand slightly toward lower Al content when the Cr content is increased. The field is slightly shifted toward lower Al content when the temperature is decreased.
Investigations into Demineralized Cortical Bone
Authors: Novitskaya Ekaterina , Castro-Ceseña Ana , Chen Po-Yu , Vasquez Joshua , Urbaniak Robert , Lee Steve , Hirata Gustavo , McKittrick Joanna
Published: April 2011

Partially demineralized (DM) bone is of interest due to its promising
osteointegrative properties for advanced bone grafts. Structural features of
partially DM (35 vol.%, 45 vol.% and 55 vol.% reduction), and untreated
cortical bone samples were studied by scanning electron microscopy.
Mechanical properties were investigated by compression testing in three
anatomical directions at different stages of DM. The radial direction
appears to be the stiffest and strongest bone direction for the all DM
stages.
Template-free, low temperature synthesis of binary and ternary metal oxide nanostructures
Authors: Brahma Sanjaya , Arod Pallavi , Shivashankar S.A.
Published: April 2011

We report synthesis of some binary and ternary metal oxide nanostructures using microwave irradiation-assisted chemical synthesis, either in the presence or absence of a surfactant/structure directing agent. The method is simple, inexpensive, and yields nanoparticles of desired metal oxides in minutes, and requires no conventional templating. Nanoparticles of some functionally advanced binary/ternary metal oxides (MnO2, ZnO, CuO, ZnMn2O4 etc) have been synthesized using metal acetylacetonates as the starting precursor material and microwave as the source of energy, in a process developed in detail in our laboratory. The nanoparticle size varies from 7-50 nm. Emphasis has been placed on the synthesis of ZnO nanostructures, particularly ZnO nanoshells, which do not require any surfactant/structure-directing agent for synthesis. There is a systematic variation in the morphology of the ZnO nanostructures with variation of process parameters, such as microwave power, microwave irradiation time, type of solvents, surfactants/structure-directing agents and its type and concentration. The as-prepared powder sample may either need a very brief exposure to heat to remove the surfactant or no post-synthesis processing, and is found to be well-crystallised. Determination of their crystallinity, actual shape, and orientation was made using X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
Thermodynamic Modeling and Solidification Simulation of Ti-Al-Cr alloys
Authors: Yang Y. , Bewlay B.P. , Chang Y.A.
Published: April 2011

Titanium aluminide based alloys are candidate materials for high temperature structural applications. They are typically alloyed with elements such as Nb, Ta, Mo, Cr and B for property enhancement. To understand the relationship between microstructure and alloy composition/processing condition, detailed models of phase equilibria in multicomponent Ti-Al based alloys are needed. In this work, we developed thermodynamic models for the phases in the Ti-Al-Cr system based on critically assessed binary models and ternary experimental data in literature, using the CALPHAD approach. Isothermal sections at 1200, 1150, 1000 and 800°C, and the liquidus projection, were calculated from the currently developed thermodynamic models; these are in satisfactory agreement with experimental data. Isopleths were calculated at specified Cr concentrations, and solidification paths were simulated under the Scheil conditions for a range of Ti-Al-Cr alloys. From the calculated phase diagrams and solidification paths, the effect of Cr on the microstructure of Ti-Al alloys can be understood.
Radiation Induced Cavity Formation and Gold Precipitation at the Interfaces of a ZrO2/SiO2/Si Heterostructure
Authors: Edmondson Philip D , Wang Chongmin , Zhu Zihua , Namavar Fereydoon , Weber William J , Zhang Yanwen
Published: April 2011

Thin films nano-crystalline zirconia of ~ 300 nm thick were deposited on Si substrate, and the samples were irradiated with 2 MeV Au+ ions at temperatures of 160 and 400 K, up to fluences of 35 displacements per atom. The films were then studied using glancing incidence x-ray diffraction, Rutherford backscattering, secondary ion mass spectroscopy and transmission electron microscopy. During the irradiation, cavities were observed to form at the zirconia/silicon interface. The morphology of the cavities was found to be related to the damage state of the underlying Si substrate. Elongated cavities were observed when the substrate is heavily damaged but not amorphized; however, when the substrate is rendered amorphous, the cavities become spherical. As the ion dose increases, the cavities then act as efficient gettering sites for the Au. The concentration of oxygen within the cavities determines the order in which the cavities getter. Following complete filling of the cavities, the interface acts as the secondary gettering site for the Au. The Au precipitates are determined to be elemental in nature due to the high binding free energy for the formation of Au-silicides.
Nanowire Tunnel FETs - Device Structure, Transistor Dimension and Material Choice
Authors: Knoch J.
Published: April 2011

The performance of tunnel FETs is investigated and the impact of device structure and dimension as well as the impact of the transistor material will be studied. For instance, using nanowires with thin diameter providing one-dimensional transport together with a wrap-gate device structure strongly improves the tunnel FET performance. In addition, the use of III-V type II heterostructures is a further performance booster. However, the use of III-V semiconductors with low density of states can be problematic if the device is not designed properly. Here we will give design guidelines and performance predictions of nanowire tunnel FETs based on non-equilibrium Greens functions formalism simulations.
Deep-Level Characterization of Free-Standing HVPE-grown GaN Substrates Using Transparent Conductive Polyaniline Schottky Contacts
Authors: Nakano Yoshitaka , Matsuki Nobuyuki , Lozac’h Mickael , Sakoda Kazuaki , Sumiya Masatomo
Published: April 2011

We have investigated electronic deep levels in free-standing n-GaN substrates grown by hydride vapor phase epitaxy (HVPE), by means of a steady-state photo-capacitance spectroscopy technique, using transparent conductive polyaniline Schottky contacts. Two specific deep levels located at ~1.7 and ~3.1 eV below the conduction band were revealed to be significantly reduced compared to those in n-GaN layers grown by metal-organic chemical vapor deposition. This difference between them is probably due to extremely low concentrations of threading dislocations and residual C impurities in the HVPE-grown n-GaN substrates.
The Effect of Fine M2C (M: Mo, Cr, Fe) Particles on the Recrystallization Temperature and High Temperature Strength of Warm Rolled Fe3Al Based Alloys
Authors: Kobayashi Satoru , Takasugi Takayuki
Published: April 2011

The effect of fine M2C particles on the recrystallization temperature and high temperature strength of warm rolled Fe3Al base alloys was investigated. Fe-27Al-1.2C-2Cr-xMo (x: 0.3, 0.9) alloys (in at.%) were arc melted, warm rolled and annealed. TEM observations have revealed that fine M2C particles were present in the alloy containing 0.9% Mo but not in the alloy with 0.3% Mo after warm rolling. The recrystallization temperature increased from 740 °C to 810 °C when the Mo content is increased from 0.3 to 0.9 due to the presence of fine M2C particles. Tensile tests conducted on annealed samples with fine sub-grained matrix have shown that the introduction of fine M2C particles is effective to enhance the proof stress at 600 °C.
AlN Nanorods synthesized by a Mechanothermal Process
Authors: Rosas G. , Chihuaque J. , Patiño-Carachure C. , Esparza R. , Pérez R.
Published: April 2011

Well-crystallized AlN nanorods have been produced by mechanical milling and subsequent annealing treatment of the milling powders (mechanothermal process). High purity AlN powders were used as the starting material. Mechanical milling was carried out in a vibratory SPEX mill for 30 h, using vials and balls of silicon nitride. The annealing treatment was carried out at 1200 ºC for 10 min. The characterization of the samples was performed by X-ray diffractometry and transmission electron microscopy (TEM). TEM observations indicated that the synthesized nanorods consisted of 30 nm in diameter and 100 nm in length. High resolution electron microscopy observations have been used in the structural characterization. AlN nanorods exhibit a well-crystallized structure. The growing direction of the nanorods is close to the [001] direction. The structural configurations have been explored through comparisons between experimental HREM images and theoretically simulated images obtained with the multislice method of the dynamical theory of electron diffraction.
Light Emitting Diode Growth on Curved Gallium Nitride Surfaces
Authors: Rodak L. E. , Lee K. , Kumbham V. , Narang V. , Hornak L. A. , Korakakis D.
Published: April 2011

III-Nitride based Light Emitting Diodes (LEDs) are heavily pursued for various lighting applications due to the ability to engineer the emission through the visible wavelengths by controlling the alloy composition in the multi quantum well. Planar structures are characterized by a Lambertian emission pattern, however, depending on the applications in which the LED is employed, including but not limited to, general lighting, displays, and sensors, the emission profile may need to be more or less directional. As a result, there is significant interest in both improving the efficiency and controlling the emission profile of nitride based devices. Various components such as lenses and photonic crystals are used to improve light extraction and alter the emission profile while growth on semi-polar substrates is being pursued to minimize inherent polarization effects. In this work, curved Gallium Nitride (GaN) structures have been grown utilizing growth kinetics. These as-grown features do not require the extensive additional fabrication and allow for three-dimensional substrates to be employed for LED fabrication. The details of the fabrication and the optical and electrical characterization of Indium Gallium Nitride based LEDs grown on these structures is discussed.
Employing Photo-Assisted Ligand Exchange Technique in Layered
Quantum Dot LEDs
Authors: Hu Wenjia , Gao Shuai , Prasad Paras N. , Wang Jingkang , Xu Jian
Published: April 2011

We presented in this paper a photo-assisted ligand exchange approach whereby
light will be introduced to facilitate the replacement of oleic acid (OA)
ligand molecules over PbSe quantum dots (QDs). The ligand-exchanged QDs were
used to fabricate quantum dot light-emitting-diodes (QD-LEDs), which
outperform the devices comprising the QDs without ligand-replacement.
Nonreciprocal optical Bloch oscillations in garnet/silicon-on-insulator waveguide arrays
Authors: Kumar Pradeep , Levy Miguel
Published: April 2011

We show that nonreciprocal Bloch-like oscillations can emerge in passive optical waveguide arrays with linearly growing effective index in the absence of loss or gain. Spectral asymmetry, a difference in propagation constants and Bloch oscillation periods in opposite propagation directions, are established by imposing different vertical spatial index gradients at the substrate/core, and core/cover interfaces in the presence of transverse magnetization. A model system consisting of an array of transversely magnetized asymmetric garnet/silicon-on-insulator waveguides is presented.
The Effect of Nb Addition on Phase Equilibria in the Ni-Rich Ni-Al-V Ternary System
Authors: Hayashi Eiki , Kobayashi Satoru , Kaneno Yasuyuki , Takasugi Takayuki
Published: April 2011

The effect of Nb addition on phase equilibria among Ni (A1), Ni3Al (L12) and Ni3V (D022) phases was investigated in the Ni-rich Ni-Al-V ternary system. The addition of Nb to the Ni-Al-V ternary system shifts the three-phase coexisting region of A1 + L12 + D022 towards the Ni-rich side at 950 ºC. Nb is partitioned into the D022 phase more strongly than the A1 and L12 phases. These results suggest that the addition of Nb stabilizes the D022 phase against the A1 and L12 phases in the systems. The alloying element raises the temperature of a eutectoid-like reaction (A1→L12+D022) by ~30 ºC in the vertical section of Ni-Al-V ternary system at 75 at. % Ni.
A step by step strategy for solution-processed quantum dots
light emitting diodes
Authors: Bourvon Hélène , Le Calvez Stéphanie , Vaufrey David , Della Gatta Sylvia Meunier
Published: April 2011

Solution-based printing and coating processes have the potential to
dramatically reduce the production costs of Organic Light Emitting Diodes.
This is particularly true for Quantum Dots Light Emitting Diode (QDLEDs),
the newborn in the field of LEDs, due to quantum dots price prohibiting
wastage. Here, we report our latest results on the development of
solutionprocessed QDLEDs. We have implemented a layer by layer strategy,
from a whole evaporated small molecule based OLED to a hybrid QDLED
developed by wet deposition techniques for the first layers and by
evaporation for the last ones. Intermediate steps are discussed in this
paper.

First, we have worked on a poly(3,4-ethylenedioxythiophene
poly(styrenesulfonate) (PEDOT:PSS) layer. The PEDOT:PSS formulation for
inkjet printing and spin coating were optimised: wettability on an ITO
substrate, jettability of the inkjet formulation and baking conditions were
studied. Additives as surfactant and ethylene glycol were added to the
commercial inkjet grade solution to improve the deposition process. As a
consequence to this study, anisotropic conductivity of PEDOT:PSS was
observed and is reported here. In particular, ethylene glycol demonstrated a
strong ability to increase the parallel conductivity by several orders of
magnitude, but not the vertical one.

Then, inkjet-printed and spin-coated device performances are compared to
complete this first study. Hybrid devices with an efficacy of 12cd/A at 4V
were obtained, with 2.17 % of EQE, and a luminance of 4000 cd/m2
at 4V.

Finally, we succeeded in the development of our first QDLED based on CdSe
core/ CdSZnS shell quantum dots emitting at a wavelength of 600nm. Quantum
dots were inkjet printed, in order to waste as little as possible this very
expensive material.
Magneto-photonic ring circulator in Bismuth Iron Garnet thin film: design and fabrication
Authors: Magdenko L. , Popova E. , Smigaj W. , Beauvillain P. , Keller N. , Gralak B. , Gogol P. , Megy R. , Vanwolleghem M. , Dagens B.
Published: April 2011

Magneto-optical garnet based optical circulator was designed and fabricated with wafer-scale technology. Modeling and simulation strategy is established for the optimization of a new design of circulator based on ring cavity. Wafer-scale technological process is developed and demonstrated allowing fabrication of the optimized BIG/GGG buried ring circulator.
Modeling W-V and W-Ta Alloys for Fusion Applications: Phase Stability, Short-Range Order and Point Defect Properties
Authors: Muzyk M. , Nguyen-Manh D. , Kurzydlowski K.J. , Baluc N.L. , Dudarev S.L.
Published: April 2011

We have performed density-functional theory (DFT) calculations of phase stability, formation energies of radiation defects in tungsten-based binaries W-Ta and W-V. These alloys are candidate for DEMO divertor applications because of their high melting point and expected improved ductility and fracture toughness in comparison with tungsten. We have identified the lowest energy intermetallic compounds, which should form at low temperatures, and calculated the effective inter-atomic interactions. Using Monte-Carlo calculations, we calculated the temperature of order-disorder phase transformations for these alloys. The predicted temperature of order-disorder phase transformations is relatively low and at high temperature it is found that the short-range order is present for both alloys. Ab-initio calculations also show that vanadium atoms strongly trap self-interstitial atom defects in W-V alloys, whereas Ta atoms in W-Ta alloys have very little effect on either the formation energy or thermally activated mobility of self-interstitial atom defects.
The observation of surface-softening in Fe-based metallic glass
Authors: Masood Ansar , Ström V. , Belova L. , Oak J.J. , Ågren J. , Rao K. V.
Published: April 2011

Depth sensing nano-indentation investigations have been performed to determine the radial dependence of the hardness through the cross section of a Fe-based bulk glassy rod. We have found the hardness of the material decreases along radius from the centre to the outermost surface. This phenomenon is attributed to the ‘cooling rate induced surface softening’. Furthermore, a significant change (~15 %) in elastic modulus is noticed along the radius as well.
Atomistic to Continuum Constitutive Modeling of Radiation Damage on FCC Metals and its Adaptation for the Generation of New Materials
Authors: Krishna Shree , De Suvranu
Published: April 2011

The paper presents a rate-independent dislocation growth and defect annihilation mechanism to capture the pre- and post-yield material behavior of FCC metals subjected to different doses of neutron radiation. Based on observation from molecular dynamics simulation and TEM experiments, the developed model is capable of capturing the salient features of irradiation induced hardening including increase in yield stress followed by yield drop and non-zero stress offset from the unirradiated stress-strain curve. The key contribution is a model for the critical resolved slip resistance that depends on both dislocation and defect densities which are governed by evolution equations based on physical observations. The result is an orientation-dependent nonhomogeneous deformation model which accounts for defect annihilation on active slip planes. Results for both single and polycrystalline simulations of OFHC copper are presented and are observed to be in reasonably good agreement with experimental data. Extension of the model to other FCC metals is straightforward and is currently being developed for BCC metals giving its way for generation of new materials.
Corrosion behavior of martensitic/ferritic oxide dispersed strengthened steels in nitric media
Authors: Gwinner Benoit , Auroy Martin , Mas Dominique , Saint-Jevin Audrey
Published: April 2011

The corrosion behavior of three martensitic/ferritic oxide dispersed strengthened (ODS) steels with different chromium contents (respectively 9, 14 and 18wt %) has been studied in hot and concentrated nitric acid. Immersion and electrochemical tests have been carried out in different experimental conditions (temperature and nitric acid concentration). In each case, the corrosion kinetics has been characterized by mass loss measurement of samples (immersion tests) and the electrochemical behavior by linear sweep voltammetry techniques. The dependency of the corrosion rate with the chromium content in the steel, the nitric acid concentration and the temperature, has been quantitatively established and qualitatively discussed.
Coming Full Circle: The Application of Microtechnology Techniques to Evaluate Bulk Materials
Authors: Read David , Barbosa Nicholas
Published: April 2011

A tensile test procedure that accommodates specimens with gage section 25 μm thick, 70 μm wide and 360 μm long was developed and demonstrated. The instrumentation and technique were adapted from those previously developed and used to test thin films, by increasing both the force capacity of the load cell and the stiffness of the pull rod. Specimens with bow-tie geometry were fabricated by photolithography from nominally 25 μm thick full hard stainless steel 302 foil. A silicon test frame fabricated by bulk micromachining techniques included tapered grips in the form of recesses in its top surface that accepted and retained the specimen grip sections. One grip was on the fixed outer portion of the frame. The other grip was on a plate suspended in the center of the frame by long slender silicon beams. Force was imposed on this plate by pin loading. The force was measured by use of a custom load cell. The displacement was measured by sub-pixel digital image correlation to surface features on the two ends of the gage section, applied to images with a resolution of approximately 0.8 μm per pixel. Yield and ultimate strengths and elongation values consistent with vendor-provided information were obtained. The values of Young’s modulus were scattered but within the range of expected behavior for the specimen material.
Density Functional Theory Calculations of Properties of the Grain Boundaries in Aluminum
Authors: Muzyk Marek , Kurzydlowski Krzysztof J.
Published: April 2011

The Density Functional Theory has been used to analyze an inter-granular segregation of Cu and Mg. The stability of Cu and Mg atoms in the aluminum matrix, intermetallic phases and symmetric twist grain boundaries has been compared. The quantitative description of solubility of Cu and Mg atoms in the nano-crystalline aluminum has been proposed. The calculations have been carried out to investigate the properties of symmetric twist boundaries in aluminum with and without Cu/Mg atoms. The phenomena of are discussed and its effect on the stability of precipitates containing these elements.
From lignin to spruce: Poromechanical upscaling of wood
strength
Authors: Bader Thomas K. , Hofstetter K. , Hellmich Ch. , Eberhardsteiner Josef
Published: April 2011

Wood strength is highly anisotropic, due to the inherent structural
hierarchy of the material. In the framework of a combined random-periodic
multiscale poro-micromechanics model, we here translate compositional
information throughout this hierarchy into the resulting anisotropic
strength at the softwood level, based on “universal” elastic properties of
cellulose, hemicelluloses, and lignin, and on the shear strength of the
latter elementary constituent. Therefore, derivation of the elastic energy
in a piece (representative volume element – RVE) of softwood, stemming from
homogeneous macroscopic strains prescribed in terms of displacements at the
boundary of the RVE and from pressure exerted by water filling the
nanoporous space between the hemicelluloses-lignin network within the cell
walls, with respect to the shear stiffness of lignin, yields higher order
strains in the lignin phase, approximating micro-stress peaks leading to
local lignin failure. Relating this (quasi-brittle) failure to overall
softwood failure (or strictly speaking, elastic limit of softwood) results
in a macroscopic microstructure-dependent failure criterion for softwood.
The latter satisfactorily predicts the biaxial strength of spruce at various
loading angles with respect to the grain direction. The model also predicts
the experimentally well-established fact that uniaxial tensile and
compressive strengths, as well as the shear strength of wood, depend
quasi-linearly on the cell water content, but highly nonlinearly on the
lumen porosity.
Porous Scaffolds Consisting of Collagen, Chondroitin Sulfate,
and Hydroxyapatite with Enhanced Biodegradable Resistance for Cartilage
Regeneration
Authors: Kaneda H. , Ikoma T. , Yoshioka T. , Nishi M. , Matsumoto R. , Uemura T. , Cross J. S. , Tanaka J.
Published: April 2011

Porous scaffolds of alkaline-soluble collagen including nanocomposite
particles of chondroitin sulfate and low crystalline hydroxyapatite for
cartilage regeneration were fabricated by freeze-drying and thermal
dehydration treatments; porous collagen scaffolds were also synthesized as a
reference. The scaffolds were cross-linked using glutaraldehyde (GA) vapor
treatment in order to enhance biodegradable resistance. Microstructural
observation with scanning electron microscope indicated that the scaffolds
with and without GA cross-linkage had open pores between 130 to 200 μm in
diameter and well-interconnected pores of 10 to 30 μm even after
cross-linkage. In vitro biodegradable resistance to
collagenase was significantly enhanced by GA cross-linking of the scaffolds.
All these results suggest that the GA cross-linked scaffolds consisting of
collagen, chondroitin sulfate, and low crystalline hydroxyapatite have
suitable microporous structures and long-term biochemical stability for
cartilage tissue engineering.
Atomistic Study of Helium Bubbles in Fe: Equilibrium State
Authors: Stewart David M. , Osetskiy Yury N. , Stoller Roger E.
Published: April 2011

In the fusion irradiation environment, helium created by transmutation will play an important role in the response of structural materials to neutron radiation damage. Recently we have developed a new 3-body potential to describe the Fe–He interaction in an Fe matrix. We have used this potential to investigate the equilibrium state of He bubbles embedded into the bcc Fe matrix. We have investigated bubble size, He content and temperature effects. It was found that the equilibrium He content is rather low and at a room temperature it is ~0.38 to 0.5 He per vacancy for bubble diameters from 1 to 6 nm. At constant bubble size, the equilibrium He/vacancy ratio decreases with temperature increase. For bubbles of 6 nm diameter it goes down as low as ~0.25 at 900K. The results are compared with the capillarity model often used for estimating the equilibrium pressure of He bubbles.
Phase State and Physical Properties of the Mo-Ru-Ph-Pd Alloys
Authors: Sugahara Tohru , Kurosaki Ken , Yusufu Aikebaier , Muta Hiroaki , Ohishi Yuji , Yamanaka Shinsuke , Komamine Satoshi , Ochi Eiji
Published: April 2011

Mo3Ru5MPd (M = Ru, Rh, Pd) as the simulated materials for the undissolved residue in the nuclear fuel reprocessing were prepared by arc melting method. The physical properties and oxidation behavior of the alloys were evaluated from viewpoint of the safety and economy in the reprocessing. The electrical resistivity, ρ, of Mo3Ru5RhPd was shown to be 0.8 μΩm at room temperature. On the other hand, the ρ values of samples without Rh were marked at 0.4 μΩm. The thermal properties of the each sample had the different thermal transfer characteristics. In particular, although the thermal conductivities of Mo3Ru5RhPd and Mo3Ru5Pd2 samples show almost the same value, the lattice thermal conductivities of both samples showed different values. Oxidation behavior was analyzed using the thermogravity(TG) and differential thermal analyses(DTA). The TG curve of each sample by oxidation showed different results. These results indicate that the simulated materials of the alloys without Rh: Mo-Ru-Pd were not appropriate to simulate the thermophysical characteristics of the typical simulated materials with undissolved residue Mo-Ru-Rh-Pd alloys. Therefore, in the spent nuclear fuel reprocessing, the mock test of reprocessing without to use Rh is difficult to carry out.
The Effect of Microwave Radiation on Tensile Properties of
Silkworm (B. mori) Silk
Authors: Reed Emily J. , Viney Christopher
Published: April 2011

We have developed a reproducible protocol for studying the effect of
microwave radiation on the mechanical behavior of Bombyx
mori cocoon silk. In the course of this work, we identified
multiple improvements that can be made to ASTM F 1317-98, the standard
according to which microwave oven power output is calibrated.

Exposure to microwaves does not significantly affect mechanical properties
of silkworm silk, if samples are kept in a desiccator after degumming (or
after degumming and microwaving) and prior to testing in a dry environment.
This finding contrasts with previous work in which samples were not kept in
a desiccator, and were tested in a relatively humid environment.

Because the effect of microwave radiation on the mechanical behavior of silk
is sensitive to ambient moisture, meaningful comparison or pooling of test
results acquired in different laboratories is contingent on standardization
of both the sample storage environment and the environment in which samples
are tested. Interpretation of the extensive existing literature on silk
mechanical properties must take account of the reality that the sample
storage and testing environments are not standardized and are usually not
reported.