bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution processable high band gap hosts based on carbazole functionalized cyclic phosphazene cores for application in organic light‐emitting diodes
Authors: Soh Mui Siang , Santamaria Sonsoles Amor Garcia , Williams Evan Laurence , Pérez‐Morales Marta , Bolink Henk J. , Sellinger Alan 
Published: January 2011

AbstractA new class of solution processable dendrimers based on cyclic phosphazene (CP) cores have been prepared and used as host materials for blue and green organic light emitting diodes (OLEDs). The dendrimers are prepared in high yield from minimal step reactions, are soluble in common solvents for solution processing, are amorphous, and have excellent thermal properties necessary for application in OLEDs. OLED efficiencies of 10.3 cd/A (4.2 lm/W) and 35.3 cd/A (33.5 lm/W) were achieved using commercially available FIrpic and Ir(mppy)3 as blue and green phosphorescent emitters, respectively. These efficiencies were 2× higher than control devices prepared using poly(N‐vinylcarbazole), the most commonly used host material in solution processed phosphorescent OLEDs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Synthesis of Liquid Organic Compounds from CH4 and CO2 in a Dielectric Barrier Discharge Operating at Atmospheric Pressure
Authors: Scarduelli Giorgina , Guella Graziano , Ascenzi Daniela , Tosi Paolo 
Published: January 2011

AbstractDue to increasing attention to environmental problems, the conversion of methane and carbon dioxide into more useful chemicals represents an attractive goal. The present work reports on the formation of a liquid (20% in weight) during the dry reforming of methane in a dielectric barrier discharge at atmospheric pressure. Nuclear magnetic resonance spectroscopy allows to define the Methyl Branching Index, which estimates the amount of branching in the liquid material. The latter consists of a wide distribution of highly methyl‐branched, medium sized (15–25 carbon atoms) hydrocarbon molecules. Oxygenated compounds, mainly alcohols and ketones, are also present in the liquid sample. magnified image
The Influence on Cell Growth Properties in Different Microtiterplate Types by Corona‐Dielectric Barrier Discharge Plasma at Atmospheric Pressure
Authors: Hähnel Marcel , Diener Annette , Kolukisaoglu Üner , Weltmann Klaus‐Dieter , Thurow Kerstin 
Published: January 2011

AbstractIn high throughput processes with living cells maintenance of sterility is a cost‐intensive but essential requirement. In the course of this work an atmospheric plasma process was developed for the sterilization of microtiterplates in such assays. In a next step it was necessary to investigate, if this plasma treatment changes surface properties for cell growth of different microtiterplate types. The results showed that this kind of plasma treatment did not significantly alter growth characteristics of different cell types in microtiterplates which were tissue culture treated or coated with collagen I or poly‐D‐lysine. Furthermore, these results revealed no detrimental effects of the applied corona‐dielectric barrier discharge (corona‐DBD) procedure on the tested surfaces and is therefore suitable for the sterilization of microtiterplates in automated cellular assays. magnified image
Defect structure in Zn+ implanted Si: HRXRD study
Authors: Shcherbachev Kirill , Privezentsev Vladimir , Saraykin Vladimir , Podgornyy Dmitry 
Published: January 2011

AbstractThe defect structure of the layer damaged by implantation with 64Zn+ ions and its evolution during subsequent annealing was studied by high‐resolution X‐ray diffraction combined with secondary ion mass spectrometry and Auger electron spectroscopy methods. The samples were pieces of n‐type Si(001) wafer cut from a Czohralski grown ingot. The samples were implanted with 64Zn+ ions at an energy of 100 keV and an ion dose of 2 × 1014 cm−2 with subsequent annealing at 400 °C for 60 min and 700 °C for 10 min. The strain and Debye–Waller depth profiles determined from the diffraction patterns were analyzed and compared to Zn profiles. Annealing leads to significant changes in the shape of the profiles. These changes can be caused by annihilation of Frenkel pair components, redistribution of both radiation‐induced point defects and the implanted impurity, and quasi‐chemical reactions between point defects and implanted impurity. Analysis of Si(‐2‐24) reciprocal space maps confirms that the damaged layer remains fully coherent to the Si matrix in as‐implanted state and after the heat treatments. The increase of X‐ray diffuse scattering intensity after annealing is caused by clustering of radiation‐induced point defects and implanted Zn atoms.
Stability against hydrogen plasma exposure of Al‐doped zinc oxide thin film for a‐Si thin film solar cell
Authors: Yoo Hana , Lim Yong Hwan , Choi Bum Ho , Lee Jong Ho , Shin Dong Chan 
Published: January 2011

AbstractIn this study, the stability of Al‐doped zinc oxide (AZO) films under hydrogen (H2) plasma exposure was investigated. The plasma power was varied from 60 to 300 W, and the exposure time was also varied from 10 to 60 min to investigate the stability of the films against H2 plasma. Surface morphologies of the AZO films did not change much after H2 plasma exposure. The average optical transmittance was 87.4% at a plasma power of 60 W and decreased to 70.9% when the plasma power was 300 W. The electrical properties, including mobility and resistivity, were improved by plasma treatment. The characteristics of AZO films after H2 plasma exposure showed negligible differences in morphology and improved optical and electrical properties, which implies that the prepared AZO films have a strong resistance to H2 plasma exposure up to an RF power of 60 W for 20 minutes. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement in alignment of single‐walled carbon nanotubes grown on quartz substrate
Authors: Hata Kensuke , Ohno Yutaka , Kishimoto Shigeru , Mizutani Takashi 
Published: January 2011

AbstractAligned growth of single‐walled carbon nanotubes (SWNTs), which can be realized on a quartz substrate, is important for electron device applications such as high‐frequency transistors. In order to improve the alignment of the SWNTs, we studied pretreatments of the substrate before SWNT growth. When the surface of the quartz substrate was etched using hydrofluoric acid, the alignment and linearity of the grown SWNTs improved. This suggests that it is important to remove the uppermost layer on the surface of as‐received substrates, which is damaged due to the polishing process. We also studied an etching process to remove the damaged layer without increasing surface roughness (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon doping for p‐type GaP and GaPN in molecular beam epitaxy using carbon tetrabromide source
Authors: Liu Zhengxin , Kawanami Hitoshi , Sakata Isao 
Published: January 2011

AbstractCarbon doping for p ‐type GaP and GaPN using carbon tetrabromide (CBr4) source in rf plasma molecular beam epitaxy was investigated. The doping concentration could be easily controlled by adjusting CBr4 pressure, and a wide region of hole concentration form ∼1017 to ∼1019 cm‐3 was obtained in both GaP and GaPN. It was found that the activation ratio of carbon in GaPN is lower than that in GaP. The hole concentration and mobility in GaPN do not change with nitrogen content at a wide region from 0.5 to 3%. The Hall mobility values in GaP and GaPN were ∼120 and ∼50 cm2/Vs at a hole concentration of ∼1 × 1017 cm‐3. Photoluminescence measurement show that the carbon incorporation reduces the intensity of luminescence, and the relative peak intensity decreases with the increase of hole concentration. This implies the existence of carbon‐related defects that quench the luminescence (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain relaxation mechanism of InGaN thin film grown on m ‐GaN
Authors: Hanada Takashi , Shimada Taka‐aki , Ji Shi‐Yang , Hobo Kenji , Liu Yuhuai , Matsuoka Takashi 
Published: January 2011

AbstractInGaN films were grown on off‐axis m ‐GaN substrates by metalorganic vapor phase epitaxy. Rocking curves of X‐ray diffraction around c‐axis revealed that Inx Ga1‐xN films incline to ±a1 direction when the film thickness and In composition x exceed a certain critical condition. The strain relaxation mechanism by introducing a2 and ‐a3 misfit dislocations at the interface is deduced from the ±a1 inclination. The rocking curves are reproduced fairly well by the scattering‐intensity calculations according to the atomic displacements caused by an array of the misfit dislocations, whose intervals are given by an asymmetric distribution function. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Device loading effect on nonresonant detection of terahertz radiation in dual grating gate plasmon‐resonant structure using InGaP/InGaAs/GaAs material systems
Authors: El Moutaouakil Amine , Suemitsu Tetsuya , Otsuji Taiichi , Videlier Hadley , Boubanga‐Tombet Stephane‐Albon , Coquillat Dominique , Knap Wojciech 
Published: January 2011

AbstractWe report on nonresonant detection of terahertz radiation using our original InGaP/InGaAs/GaAs plasmon‐resonant high‐electron‐mobility transistor having a dual grating gate (DGG) structure. The experiments were performed at room temperature using a Gunn diode operating at 0.30 THz as the THz source. Using a device‐loading model, the intrinsic responsivity was extracted and was dependent on the polarization of the incident THz wave. The device exhibited highest response when the electric‐field vector of the incident THz radiation was directed in the source‐drain direction. The 2D spatial distribution image of the transistor responsivity shows a clear beam focus centred on the transistor position, which proves the appropriate coupling of the THz radiation to the device, due to the DGG structure. The device also showed a high intrinsic responsivity of ∼90 V/W and a noise equivalent power (NEP) as low as ∼10‐10 WHz‐0.5. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Control of stochastic resonance response in a GaAs‐based nanowire field‐effect transistor
Authors: Kasai Seiya , Shiratori Yuta , Miura Kensuke , Nakano Yuta , Muramatsu Toru 
Published: January 2011

AbstractControl of stochastic resonance (SR) response in a GaAs‐based nanowire FET is investigated for its application to nanoelectronics. The SR is a phenomenon in which the response to a weak signal is optimized by adding noise. Experiments clarify that the peak position is controlled by the gate offset voltage. The peak height also depends on the offset voltage and decreases when the peak position places in high noise region. Theoretical analysis indicates that the peak position depends only on the offset voltage whereas the height is also controlled by device dimensions. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
N‐doping induced band‐gap reduction in III‐V semiconductors: First‐principles calculations
Authors: Ishikawa Masato , Nakayama Takashi 
Published: January 2011

AbstractNitrogen doping often induces the band‐gap reduction for III‐V semiconductors. To understand its origin and feature, the chemical trend of reduction is studied by the first‐principles calculation with comparing the cases of various III‐V compounds. We found that III‐V semiconductors are categorized al least into two groups; the large band‐gap reduction occurs for InP, InAs, InSb, GaAs, and GaSb, while there is little reduction and appears a deep level of nitrogen in the band gap for AlAs, AlP, AlSb, and GaP. It is shown that such difference reflects the order of energy positions of host cation s‐orbital and the nitrogen 3s‐orbital states. Reflecting orbital hybridization originated from such difference, calculated optical spectra show different features near absorption edges (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement of terahertz detection efficiency in electro‐optical sampling using Fabry‐Perot microcavity structure
Authors: Shirai Hideto , Uzumi Keiji , Koshiba Shyun , Nakanishi Shunsuke , Itoh Hiroshi , Tsurumachi Noriaki 
Published: January 2011

AbstractWe have fabricated a Fabry‐Perot (FP) microcavity in the THz region with a GaP crystal as the cavity layer by using a simple stacking method. We utilized the FP cavity structure as the electro‐optic (EO) material for THz wave detection in the EO sampling of THz time domain spectroscopy. We observed three‐fold enhancement in the THz detection efficiency in the FP cavities as compared to the bare GaP crystal at the frequencies of resonant modes and stopband edges. This enhancement in THz detection efficiency is caused by the incidental THz electric field enhancement effect in the FP cavity. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
HVPE growth of AlN on trench‐ patterned 6H‐SiC substrates
Authors: Okumura Kenta , Nomura Takuya , Miyake Hideto , Hiramatsu Kazumasa , Eryuu Osamu 
Published: January 2011

AbstractAlN films were grown on patterned SiC with stripes along the 〈1‐100〉 and 〈11‐20〉 directions by hydride vapor phase epitaxy and characterized by scanning electron microscope, atomic force microscopy and high‐resolution X‐ray diffraction. Although the critical thickness of AlN can be increased significantly using both patterns, AlN grown on 〈1‐100〉‐patterned SiC was more easily coalesced than that on the 〈11‐20〉 pattern. Moreover, the surface morphology and crystal quality of samples grown on 〈1‐100〉‐patterned SiC were better than those on 〈11‐20〉‐patterned substrates (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence spectra and carrier capture processes in sparsely‐spaced InAs quantum dot systems
Authors: Ohmori Masato , Vitushinskiy Pavel , Sakaki Hiroyuki 
Published: January 2011

AbstractWe have investigated photoluminescence (PL) spectra of sparsely‐spaced InAs self‐assembled quantum dots (QDs) in a GaAs matrix, grown by molecular beam epitaxy. The dot density of samples measured in this study ranges from 2×107 to 7.6×105 cm‐2. From the dot density dependence of PL intensity of the QDs and the wetting layer (WL), we have obtained the carrier capture radius of individual QD in the plane of the WL and found it to be 540 nm at 11 K. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐assembly formation of the magic ion of (H2O)20O+: observation of nanoscale cages of oxygenated water clusters induced from iron nanoparticles
Authors: Wu Hui‐Fen , Chin Chen‐Che , Liu Bo‐Min , Chen Yuan‐Chin , Lin Chi‐Hsien , Chang Kai‐Di , Lee Yi‐Hsien 
Published: January 2011

AbstractFor the first time, we observed a stable and intense ion (m/z 376) of the oxygenated water cluster ion ((H2O)20O+) produced from simply spraying an aqueous solution of iron nanoparticles (Fe NPs) into an electrospray mass spectrometry (ESI‐MS) system. Tandem mass spectrometric (MS/MS and MS/MS/MS) results were applied to identify the assignments of the fragment ions of m/z 376 in order to explore the possible structures of this cluster ion. The possible structures of the (H2O)20O+ ions are proposed as pentagonal dodecahedron water clathrate cages from the results of tandem mass spectrometry since eliminations of five water molecules were frequently observed in the MS/MS results for many subsequent fragment ions of m/z 376. The formation of this oxygenated water cluster ion ((H2O)20O+) in ESI‐MS is attributed to the high surface reactivity and surface energy of Fe NPs during ESI processes (under high temperature and high voltage (5 kV) of ESI spray environment). We believe that the observation of self‐assembly formation of oxygenated water clusters is an important issue in nanoscience as well as in the fields of water clusters. Copyright © 2011 John Wiley & Sons, Ltd.
Liquid chromatography/tandem mass spectrometry for analysis of 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6‐tetrabromocyclooctane (TBCO)
Authors: Zhou Simon Ningsun , Reiner Eric J. , Marvin Chris H. , Helm Paul A. , Brindle Ian D. 
Published: January 2011

AbstractAlthough the two flame retardants 1,2‐dibromo‐4‐(1,2‐dibromoethyl)cyclohexane (TBECH) and 1,2,5,6‐tetrabromocyclooctane (TBCO) have been widely used, a selective instrumental method of analysis for these compounds has not been developed to date. In this study, we demonstrate the feasibility to utilize liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the separation and analysis of α‐ and β‐TBCO and α‐, β‐, γ‐, and δ‐TBECH. Acetone was initially used in a tetrahedron solvent system for LC optimization. A simple isocratic elution allowed near‐baseline separation of these compounds. Different ionization approaches and mechanisms were investigated. The mass spectrometric transition of [M + O2]– => Br– (459.8 => 78.9) was a selective detection method for the target analytes. Good instrument detection limits (5 pg for γ‐/δ‐TBECH, 125 pg for α‐/β‐TBECH, and 30 pg for α‐/β‐TBCO with 2.0 µL injection) were obtained. Excellent linearity up to 50 ng/µL (R2 >0.999) was also achieved. This method has been applied to environmental samples (surface water) for screening purposes with recoveries ranging from 76–92% (CV%: 5–8%). This method shows significant improvement over previous methods. Copyright © 2011 John Wiley & Sons, Ltd.
A Fuzzy Logic Based Approach to Assess Sustainable Development of the Mining and Minerals Sector
Authors: Kommadath Basanth , Sarkar Runa , Rath Binayak 
Published: January 2011

ABSTRACTAssessing sustainable development, especially of the mining and minerals sector, is a challenge. This paper is an attempt to address this challenge by developing a methodology using fuzzy logic that encompasses the definitions, fundamentals, economic underpinnings and criteria of sustainable development. The paper starts by distinguishing the newly conceptualized ‘assessment for sustainability’ from the generally practiced ‘sustainability assessment’, framework, clarifying that the former looks at the process in question and lays out the path to be followed to assess sustainability, while the latter is just a static report. It then highlights the inherent limitations of the three traditional sustainability assessment tools and attempts to improve upon these limitations by proposing a model using fuzzy logic, weak sustainability criteria and context‐dependent sustainability indicators to assess sustainable development of the mining and minerals sector. As an illustration, the paper demonstrates how the proposed methodology can be applied to a reference town, where mining is the primary economic activity. The results derived can be used internally for identification of ‘hot spots’ as well as externally for sustainability reporting and stakeholder engagement. Assessment for sustainability also facilitates monitoring, estimating the degree of sustainability and defines a course of action for stakeholders as well as policy‐makers to improve a project's degree of sustainability. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
Entry into new niches: the effects of firm age and the expansion of technological capabilities on innovative output and impact
Authors: Kotha Reddi , Zheng Yanfeng , George Gerard 
Published: January 2011

AbstractWe provide evidence that young firms systematically differ from older firms in their innovative output when they enter ‘new to the firm’ technological niches. We analyze data from 128 biotechnology firms since their inception and track these firms over time. Our analyses reveal that the organizational age at which the firm branches into new technological niches significantly influences its innovative activity. We refine the focus of the extant literature by separately examining the effects of branching on the quantity of innovative output and the impact that this output has on the technology domain. Subsequent to branching into new niches, we find that older firms have a higher quantity of output than their younger counterparts, whereas young firms tend to outpace their older rivals with higher impact. We discuss the implications of these findings for the literature on dynamic capabilities and entrepreneurship. Copyright © 2011 John Wiley & Sons, Ltd.
When are assets complementary? star scientists, strategic alliances, and innovation in the pharmaceutical industry
Authors: Hess Andrew M. , Rothaermel Frank T. 
Published: January 2011

AbstractTo answer the question of when are assets complementary, we investigate specific resource combinations along the value chain, focusing on two mechanisms that are central to combining resources for innovation in the pharmaceutical industry: recruitment and retention of star scientists, and 2) engagement in strategic alliances. We propose that resource combinations that focus on the same parts of the value chain are substitutes due to knowledge redundancies. Conversely, we hypothesize that resource combinations that link different parts of the value chain are complements due to integration of nonredundant knowledge. To test these hypotheses, we empirically track the innovative performance of 108 global pharmaceutical firms over three decades (1974–2003). Copyright © 2011 John Wiley & Sons, Ltd.
Modeling the Flow Behavior of a High‐Manganese Steel Fe‐Mn23‐C0.6 in Consideration of Dynamic Recrystallization
Authors: Xiong W. , Wietbrock B. , Saeed‐Akbari A. , Bambach M. , Hirt G. 
Published: January 2011

AbstractIn this paper, the hot deformation behavior of a high manganese (23wt. % Mn and 0.6wt. % C) austenitic steel is analyzed. This steel is a ternary Fe‐Mn‐C alloy that shows twinning induced plasticity (TWIP). Since strip production involves hot rolling, the hot deformation behavior of this steel is analyzed and modeled by a phenomenological material model. The model takes into account strain hardening and softening by dynamic recrystallization (DRX), which is modeled using Avrami type kinetics. The evolution of grain size during DRX is also taken into account. Hot compression tests were performed in a temperature range of 900 to 1200 °C and various strain rates from 0.1 s−1 to 10 s−1 to identify the model parameters. The material model was coupled with a finite element code and validated using selected parameter combinations of the compression tests that were not used for parameter identification.