bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light-trapping in Thin Film Silicon Solar Cells with a Combination of Periodic and Randomly Textured Back-reflectors
Authors: Pattnaik Sambit , Chakravarty Nayan , Biswas Rana , Slafer D. , Dalal Vikram 
Published: November 2012

ABSTRACTLight trapping is essential to harvest long wavelength red and near-infrared photons in thin film silicon solar cells. Traditionally light trapping has been achieved with a randomly roughened Ag/ZnO back reflector, which scatters incoming light uniformly through all angles, and enhances currents and cell efficiencies over a flat back reflector. A new approach using periodically textured photonic-plasmonic arrays has been recently shown to be very promising for harvesting long wavelength photons, through diffraction of light and plasmonic light concentration. Here we investigate the combination of these two approaches of random scattering and plasmonic effects to increase cell performance even further. An array of periodic conical back reflectors was fabricated by nanoimprint lithography and coated with Ag. These back reflectors were systematically annealed to generate different amounts of random texture, at smaller spatial scales, superimposed on a larger scale periodic texture. nc-Si solar cells were grown on flat, periodic photonic-plasmonic substrates, and randomly roughened photonic-plasmonic substrates. There were large improvements (>20%) in the current and light absorption of the photonic-plasmonic substrates relative to flat. The additional random features introduced on the photonic-plasmonic substrates did not improve the current and light absorption further, over a large range of randomization features.
Innovative Device Architecture for High Efficiency Thin Film Silicon Solar Cells
Authors: Boccard Mathieu , Despeisse Matthieu , Ballif Christophe 
Published: November 2012

ABSTRACTThe challenge for all photovoltaic technologies is to maximize light absorption, convert photons with minimal losses to electrical charges and efficiently extract them towards the electrical circuit. For thin film silicon solar cells, a compromise must be found as light trapping is usually performed through textured interfaces, that are detrimental to the subsequent growth of dense and high quality silicon layers. We introduce here the concept of smoothening intermediate reflecting layers (IRL), enabling to combine high currents and good electrical quality in Micromorph devices in the superstrate configuration. After exposing the motivation for such structures, we validate the concept by showing a VOCenhancement when employing a polished silicon-oxide-based IRL. Shunting issues and additional reflection losses are pointed out with such technique, highlighting the need to develop alternative techniques for an efficient morphology adaptation before the microcrystalline silicon cell growth.
Amorphous silicon-germanium (a-Si0.01Ge0.99:H) doped with phosphorous deposited by LF PECVD and its electrical and optical characteristics
Authors: Delgadillo N. , Kosarev A. , Torres A. , Gonzales B. 
Published: November 2012

ABSTRACTAmorphous silicon-germanium (a-Si0.01Ge0.99:H) thin film, practically amorphous germanium with small concentration of silicon, were deposited by the low frequency PECVD technique under different flow gas of phosphine in the range of QPH3 = 20 to 100 sccm. In this range the phosphorous concentration in gas phase was calculated as XP= 4 to 20 % which resulted in a content in solid phase [P]sol=0.12% - 0.4%. The P content of the solid phase was measured by SIMS profiling and it was also observed a preferential incorporation of phosphorous in the range of [P]sol=0.12% - 0.3%. Hydrogen concentration in the films was determined from FTIR and SIMS measurements. The activation energy was determined by measuring the temperature dependence of conductivity in DC regime in a vacuum thermostat. For the a-Si0.01Ge0.99:H films it is found that the activation energy have a minimum, (Ea= 0.15eV), its conductivity at room temperature have a maximum and there is a minimum of of both band tail and deep localized state for a phosphorous incorporation in solid phase [P] =0.28%.
Formation of a single In(Ga)As/GaAs quantum dot embedded in a site-controlled GaAs nanowire by metalorganic chemical vapor deposition for application to single photon sources
Authors: Tatebayashi J. , Ota Y. , Karunathillake D. , Ishida S. , Nishioka M. , Iwamoto S. , Arakawa Y. 
Published: November 2012

ABSTRACTWe report the formation and optical properties of site-controlled InAs/GaAs quantum dots (QDs) embedded in GaAs nanowires (NWs) by selective metalorganic chemical vapor deposition for application to single photon sources. InAs/GaAs QD-in-NWs with various InAs thicknesses are realized on patterned GaAs(111)B substrates in the form of InAs/GaAs heterostructures and identified by structural analyses using scanning transmission electron microscopy and photoluminescence characterization. Sharp excitonic emission peaks at 10 K from single QD-in-NWs with the narrowest exciton linewidth of 87 μeV are observed. Light emission from the single QD-in-NW shows photon antibunching which evidences single photon emission from high-quality QD-in-NWs.
Evaluation of crystal structure of porous Si nanowires prepared by metal assisted etching
Authors: Yamaguchi Takuya , Shimizu Tomohiro , Wang Chonge , Inada Mitsuru , Shingubara Shoso , Kuznetsov Aleksandr , Vanacken Johan , Moshchalkov Victor 
Published: November 2012

ABSTRACTThe macro and micro morphology of the Si surface, depending on noble metal ion concentration in etching solution, prepared by metal assisted etching were investigated. We defined the morphology of etched Si in four types, and developed the phase diagram of Si morphology. Mixture of silver nitrate (AgNO3) and hydrofluoric acid (HF) was used as an electroless-plating bath of Ag, as well as etching solution of Si. The morphology of the etched Si surface as function of concentration of AgNO3 in etching solution was observed by SEM. With increasing concentration of the AgNO3 in the etching solution, the surface of etched Si tended to be porous structure with very fine pores of a few nm (porous Si). When concentration of AgNO3is low, single crystal Si nanowires with a smooth surface without pores were observed.
Thermodynamic Tuning of Calcium Hydride by Fluorine Substitution
Authors: Pinatel Eugenio R. , Rude Line H. , Corno Marta , Kragelund Maria , Ugliengo Piero , Jensen Torben R. , Baricco Marcello 
Published: November 2012

ABSTRACTFluorine substitution in CaH2has been studied by means of experimental and theoretical methods. Samples with various compositions have been prepared by ball milling.In situX-ray diffraction analysis has been carried out as a function of temperature by synchrotron radiation experiments. An increase of mixing has been observed during heating, suggesting that mixing is thermodynamically favoured but it is kinetically hindered at low temperatures.Ab initioDFT calculations have been performed to estimate the thermodynamic mixing properties of both orthorhombic and cubic solid solutions. On the basis ofab initioresults and literature information, a thermodynamic assessment within the CALPHAD framework has been performed and the pseudo binary CaH2-CaF2phase diagram has been calculated. The formation of orthorhombic and cubic terminal solid solutions in the CaH2-CaF2system is predicted, in good agreement with experimental findings.
Copper Tungstate (CuWO4)–Based Materials for Photoelectrochemical Hydrogen Production
Authors: Gaillard Nicolas , Chang Yuancheng , Braun Artur , DeAngelis Alexander 
Published: November 2012

ABSTRACTWe report in this communication on the photoelectrochemical (PEC) performances of copper tungstate (CuWO4) material class. This study was performed on 2-micron thick samples fabricated using a low-cost co-sputtering deposition process, followed by an 8-hour long annealing at 500°C in argon. Microstructural analysis pointed out that the post-deposition treatment was critical to achieve photocatalytic activity. Subsequent characterizations revealed that polycrystalline CuWO4 photoanodes owned promising characteristics for solar-assisted water splitting, i.e (i) an optical band-gap of 2.2 eV, (ii) a flat-band potential of -0.35 V vs. SCE and (iii) conduction and valence band-edges that straddle water splitting redox potentials. CuWO4 photoanodes generated 400 μA.cm-2 at 1.6V vs. SCE under simulated AM1.5G illumination in 0.33M H3PO4 with virtually no dark current up to this potential. Impedance analysis pointed out that large charge transfer resistances (2,500 Ω.cm2) could be the main weakness of this material class. Current research activity is focused on solving this issue to achieve higher PEC performances.
Metal Oxides as Catalyst Promoters for Methanol Oxidation
Authors: Kolla Praveen , Kerce Kimberly , Fong Hao , Smirnova Alevtina 
Published: November 2012

ABSTRACTThe Transition metal oxides such as TiO2 and CeO2 as catalyst and co-catalyst materials were studied for methanol oxidation. The metal oxide nanoparticles were impregnated into carbon aerogel and Pt-Ru/C (Tanaka) by modified sol-gel Pechini method and heat-treated at different temperatures. Crystal structure, particle size and composition of the catalyst particles were studied using XRD, TEM and EDS techniques. The electrochemical activity and stability of these catalyst materials were studied in acidic medium and the results were compared to their corresponding specific and active surface areas. The aerogel supported metal oxides were stable and proved for better methanol oxidation, while a significant synergetic effect in electro-oxidation is observed when the metal oxides were impregnated into the structure of Pt-Ru/C catalyst. The methanol-oxidation was further improved after heat treatment due to its improved structural and surface properties.
Evaluation of Bioactive Glass (13-93) Scaffolds with an Oriented Microstructure for Regenerating Load-bearing Bones
Authors: Liu Xin , Rahaman Mohammed N. 
Published: November 2012

ABSTRACTBioactive glass is an attractive scaffold material for use in filling bone defects because of its widely recognized ability to support the growth of bone cells and to bond firmly with hard and soft tissue. Use of bioactive glasses in the form of porous three-dimensional scaffolds for bone repair applications has been receiving considerable interest in recent years. However, bioactive glass scaffolds have been limited to the repair of low-load bone defects because of their low strength. In the present work, porous and strong bioactive glass scaffolds with an oriented microstructure were prepared by unidirectional freezing of camphene-based suspensions, and evaluated for their ability to regenerate bone in a non-healing rat calvarial defect model. Scaffolds of 13-93 glass (53SiO2, 6Na2O, 12K2O, 5MgO, 20CaO, 4P2O5; wt%) with a porosity of 50% and columnar pores of diameter 50–150 μm showed a compressive strength of 47 ± 5 MPa and an elastic modulus of 11 ± 3 GPa. Total bone regeneration in the oriented scaffolds, 18% after implantation for 12 weeks to 24% after 24 weeks, was not significantly different from that in 13-93 scaffolds with a microstructure similar to that of dry human trabecular bone (control group). The results indicated that these oriented bioactive glass (13-93) scaffolds could potentially be used in the regeneration of loaded bone.
Rapid Growth of Radish Sprouts Using Low Pressure O2Radio Frequency Plasma Irradiation
Authors: Kitazaki Satoshi , Koga Kazunori , Shiratani Masaharu , Hayashi Nobuya 
Published: November 2012

ABSTRACTWe compared growth enhancement of radish induced by O2, air, and Ar plasma irradiation. The average length of radish sprouts cultivated for 4 days after O2plasma irradiation is 70% longer than that of sprouts without irradiation. The O2plasma irradiation is more effective in enhancing growth than air and Ar radio frequency plasma irradiation. Cell morphology and cell size of sprouts with O2plasma irradiation is nearly the same as those without irradiation. These results suggest that plasma induced acceleration of cell proliferation brings about the rapid growth.
Detection and Damage-analysis of Bio-Particles and for Safety-Evaluation of Plasma-treated water using DNA-manipulation
Authors: Mizuno Akira , Yasuda Hachiro , Kurita Hirofumi , Takashima Kazunori 
Published: November 2012

ABSTRACTEffect of non-thermal plasma (NTP) on bio-particles has been studied using Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and bacteriophages. NTP has been used, and states of different biological components were monitored during the course of the exposure. Analysis of green fluorescent protein (GFP), introduced into E.coli cells proved that NTP causes a prominent protein damages without cutting peptide bonds. We have developed a biological assay which evaluates in vivo DNA damage of the bacteriophages. Different doses of the plasma were applied to wet state of λ phages. From the plasma-exposed λ phages, DNA was purified and subjected to in vitro DNA packaging reactions. The re-packaged phages consist of the DNA from discharged phages and brand-new coat proteins. Survival curves of the re-packaged phages showed extremely large D value (D = 25 s) compared to the previous D value (D = 3 s) from the discharged phages. The results indicate that DNA damage hardly contributed to the inactivation, and the damage in coat proteins is responsible for inactivation of the phages. We also report a single-molecule-based analysis of strand breakages on large DNA molecules induced by the plasma exposure. Single-molecule observation of DNA that involved molecular combing was used to measure the length of individual DNA molecules. The measured DNA length showed that plasma exposure caused a marked change in length of DNA molecules. The rate of plasmainduced strand breakage on large random-coiled DNA molecules was determined using a simple mathematical model. The measured rate shows good relation with the plasma exposure time, and could be used for safety evaluation of the plasma treated water.
Aero-Sol-Gel Synthesis of Mesoporous TiO2 Nanoparticles and Their Photovoltaic Properties in Dye-Sensitized Solar Cells
Authors: Ahn Ji Young , Moon Kook Joo , Kim Ji Hoon , Kim Soo Hyung 
Published: November 2012

ABSTRACTHighly mesoporous TiO2 nanoparticles (NPs) were synthesized by an aero-sol-gel process in this approach. By varying the mass fraction of inorganic templates, the formation of mesoporous TiO2 NPs with optimized surface area and pore volume distributions was examined. Then, the photovoltaic properties of the resulting mesoporous TiO2 NPs were systematically investigated by applying them into the photoanode of dye-sensitized solar cells (DSSCs). The mesoporous TiO2 NP-based DSSCs fabricated in this study showed an improved short circuit current density and power conversion efficiency compared with solid TiO2 NP-based DSSCs due to the increase of the amount of inorganic dye (N719) adsorption in the mesoporous TiO2 NPs. These mesoporous TiO2 NPs fabricated have a strong potential as an effective dye supporting and electron transfer medium to improve the photovoltaic performance of DSSCs.
Supported Ni catalyst made by electroless Ni-B plating for diesel autothermal reforming
Authors: Xia Zetao , Hong Liang , Wang Wei , Liu Zhaolin 
Published: November 2012

ABSTRACTCexGd1-xO2-δ (CGO)-supported Ni nano grains were prepared initially by electrolessly depositing Ni-B alloy nano particles onto an activated carbon (AC). The as-deposited Ni-B particles were then transferred from AC to CGO through the metallo-organic precursor approach. The resultant Ni/CGO catalysts displayed excellent catalytic activity and chemical stability against coking and sulfur poisoning in catalyzing autothermal reforming (ATR) of a surrogate diesel fuel, comprising dodecane, tetralin and a substituted thiophene. For comparison purpose, a Ni/CGO catalyst prepared by the conventional impregnation method was employed in the same ATR system. These two catalytic systems exhibited rather discrepant outcomes. It was found that the Ni(B)/CGO catalyst was capable of repressing selectivity of ethylene during the reforming process. In addition to this, CGO played a critical role in thermal cracking hydrocarbon chains and inhibiting sulfur poisoning.
Response of Kudzu (Pueraria montanavar.lobata) Seedlings and Naturalized Plants to Simulated Herbivory
Authors: Frye Matthew J. , Hough-Goldstein Judith , Kidd Kathleen A. 
Published: November 2012

AbstractWe studied the response of naturalized kudzu plants to simulated herbivory at three locations: Delaware (DE), Pennsylvania (PA), and North Carolina (NC). At the DE and PA sites, plant mortality after the first yr was 14 and 50%, respectively, and was highest for plants that had a small starting root crown size. At both sites, 50 and 75% leaf and shoot clipping, and drilling one or two large holes from the root crown into roots, had no effect on aboveground biomass. In NC, all plants survived for 3 yr. Plants subject to 50% vine removal at this site showed significant decrease in aboveground biomass compared to the control, but 50% leaf cutting and root drilling had no effect. In the greenhouse, kudzu seedlings grown in 60 and 100% light compensated for 50% leaf removal, but 75% damage reduced aboveground biomass. Plants survived for 1 to 2 mo in 0% direct light, but only one of 53 plants survived to the end of the experiment. Results suggest that established kudzu plants are able to compensate for biomass removal, seedlings can survive for several weeks without light, and that effective biocontrol might require more than 2 to 3 yr of continuous damage.
Soil–Occupancy Effects of Invasive and Native Grassland Plant Species on Composition and Diversity of Mycorrhizal Associations
Authors: Jordan Nicholas R. , Aldrich-Wolfe Laura , Huerd Sheri C. , Larson Diane L. , Muehlbauer Gary 
Published: November 2012

AbstractDiversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects can inhibit growth of native plant species in invaded communities.
A Special Thanks to 2012 JOSPT Contributors
Authors: Simoneau Guy G. 
Published: November 2012

Editor-in-Chief Dr. Guy Simoneau recognizes the authors, associate editors, International Editorial Review Board members, and manuscript and musculoskeletal imaging reviewers who contributed to the various aspects of the Journal over the past 12 months. J Orthop Sports Phys Ther 2012;42(12):982–984. doi:10.2519/jospt.2012.0112
Task Motivation in Process: A Complex Systems Perspective
Authors: Poupore Glen 
Published: November 2012

Abstract:While many studies into task-based interaction have been conducted within a cognitive-linguistic perspective, few have been conducted with the aim of investigating learners’ task motivation. Framed within a complex systems approach, the principle objectives of this classroom-based study were to provide a complexity description of task motivation and to identify how various socio-affective and task condition-related elements interact together to influence learner motivation during different types of tasks. The elements include task enjoyment, effort, success expectancy, relevance, emotional state, perceived difficulty, perceived group work dynamic, and specific aspects related to the structure and content of tasks. Participants for the study consisted of 38 Korean intermediate learners of English in a conversation course as part of a TESOL certificate program. Data were collected through questionnaires during the course, at pre- and post-task, and as well, through post-task interviews. Supporting the notion that task motivation functions as a complex system, learners’ motivation decreased as a result of different combinations of socio-affective variables acting together rather than in isolation. Task conditions related to cognitive complexity and topic, furthermore, were shown to function as important control parameters in the shaping of the motivational patterns.