bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photodeposition of Metal Sulfide Quantum Dots on Titanium(IV) Dioxide and its Applications
Authors: Tada Hiroaki 
Published: September 2011

ABSTRACTIn situ photodeposition techniques taking advantage of the TiO2 photocatalysis have been developed for coupling metal sulfide quantum dots (QDs) and TiO2 at a nonoscale. The coupled metal sulfide-TiO2 systems possess the following characteristics: (I) a large amount of metal sulfides can be directly formed on TiO2 during a fairly short period with excellent reproducibility, (II) the band energies of metal sulfides QDs are widely tunable by irradiation time, (III) metal sulfide QDs can be deposited on not only the external surfaces but also the inner ones of mesoporous TiO2 nanocrystalline films without pore-blocking, (IV) the simple solution-based technique at low temperature enables the low-cost production, (V) this technique has a wide possibility for coupling TiO2 and narrow gap metal sulfides. These unique features produce the excellent performances of the resulting heteronanojunaction systems as the photoanodes for QD-sensitized solar cells.
Concepts of metal-organic decomposition (MOD) silver inks for structured metallization by inkjet printing
Authors: Schoner Claudia , Jahn Stephan F. , Jakob Alexander , Blaudeck Thomas , Lang Heinrich , Baumann Reinhard R. 
Published: September 2011

ABSTRACTIn this contribution, we report on the optimization of a metal-organic decomposition (MOD) ink based on silver(I) complexes by a systematic variation of the ink formulation. As a result, three different ink concepts turned out to be printable and resulting in a sufficiently high contour definition, layer homogeneity, and conductivity. The ink concepts include increase of the solid load, the usage of N-methyl-2-pyrrolidone (NMP) as a humectant with low vapor pressure, addition of co-solvents such as diethylene glycole and addition of sodium lauryl sulfate (SLS) as stabilizing ligand. It turns out that, for silver precursor concentrations of 40 wt%, the addition of 1 wt% SLS to aqueous inks leads to elevated conductivity up to 3.2x107 Sm-1 at maintained printability and an improved contour definition with respect to pure aqueous inks.
Reduced Resistance to Air Flow from Nanomodified Endotracheal Tubes
Authors: Machado Mary C. , Tarquinio Keiko M. , Webster Thomas J. 
Published: September 2011

AbstractVentilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would help to prevent this problem. The objective of this study was to determine differences in bacterial growth on nanomodified and unmodified ETTs under dynamic airway conditions, a bench top model based upon the general design of Hartmann et al. (1999) was constructed to test of the effectiveness of nanomodified ETTs under the airflow conditions present in the airway. Twenty-four hour studies performed in a dynamic flow chamber showed a marked difference in the biofilm formation on different areas of unmodified tubes. Areas where tubes were curved, such as at the entrance to the mouth and the connection between the oropharynx and the larynx, seemed to collect the largest amount of biofilm. On the nanomodified tubes biofilm formation was markedly different occurring on smaller pieces.The biofilm formation on ETTs in the airflow system after 24 hours showed a large difference depending upon where tubes were oriented within the apparatus. This illustrates the importance of dynamic flow on biofilm formation in pediatric ETTs. It is of particular interest that increased biofilm density on both unmodified and nanomodified tubes appeared to occur at curves in the tube where changes in flow pattern occured. This emphasizes the need for more accurate models of airflow within pediatric ETTs, suggesting that not only does flow affect pressure gradients along the tube, but in fact, determines the composition of the film itself. More testing is needed to determine the effects of biofilm formation on the efficiency of ETT under airflow, however this study provides significant evidence for nanomodification alone (without the use of antibiotics) to decrease bacteria function.
Iron fortification: Flame-made nanostructured Mg- or Ca-doped Fe oxides
Authors: Knijnenburg Jesper T.N. , Hilty Florentine M. , Teleki Alexandra , Krumeich Frank , Hurrell Richard F. , Zimmermann Michael B. , Pratsinis Sotiris E. 
Published: September 2011

ABSTRACTIron deficiency affects approximately 2 billion people worldwide, especially young women and children. Food fortification with iron is a sustainable approach to alleviate iron deficiency but remains a challenge. Water-soluble compounds with high bioavailability (e.g. the “gold standard” FeSO4) usually cause unacceptable sensory changes in foods, while compounds that are less reactive in food matrices are often less bioavailable. Solubility (and therefore bioavailability) can be improved by increasing the specific surface area (SSA) of the compound, i.e. decreasing its particle size to the nm range. Here, iron oxide-based nanostructured compounds with Mg or Ca are made using scalable flame aerosol technology. Addition of either element increased iron solubility to a level comparable to iron phosphate. Furthermore, these additions lightened the powder color and sensory changes in fruit yoghurt were less prominent than for FeSO4.
Space Heritage: The Apollo Heat Shield; Atmospheric Reentry Imprint on Materials’ Surface
Authors: Szczepanowska Hanna , Mathia Thomas G. 
Published: September 2011

ABSTRACTThe heat shield is part of a thermal protective system (TPS) essential in shielding the cargo of a spacecraft during reentry to the earth’s atmosphere. The ablated surface of the heat shield is a testimony to the harsh reentry environment, evidenced in melting and charring among other phenomena that occur during reentry at velocity of 9-11 km/sec. The aim of this study was to extrapolate information about atmospheric reentry from the surface of the ablated material. A sample of the heat shield from the test vehicle of the Apollo Program, AS-202, was the subject of the analysis.For the preliminary studies, selected investigation modes from the Global Optimal Strategy model, developed to identify wear of engineering surfaces, were applied: examination of structure, optical observation, physico-chemical characterization and surface morphology. Instrumentation used included: microscopic surface analysis with Extended Depth of Field composite images (EDF), Fourier transform infrared spectroscopy (FTIR), attenuated total reflectance (ATR), confocal scanning laser microscopy and laser scanning microscopy. The Apollo Program testing vehicle AS-202 (1966) ablated specimen sample was obtained from the collection of the National Air and Space Museum (NASM), Smithsonian Institution, Washington DC. The authors combine their diverse experiences in tribology and in artifacts’ museum conservation so as to contribute to the space heritage material science. This study represents one of the building blocks of a larger project, the Fundamental Model of public outreach and perception (FAM-pop) of complex aerospace technologies.
Mechanical Properties of Vacancy-containing Graphene and Graphite Estimated by Molecular Dynamics Simulations
Authors: Ito Akihiko , Okamoto Shingo 
Published: September 2011

ABSTRACTUsing molecular dynamics (MD) simulation, we investigated the mechanical properties of graphene and graphite, which contain cluster-type vacancies. We found that as the vacancy size increases, the tensile strength drastically decreases to at least 56% of that of pristine graphene, whereas Young’s modulus hardly changes. In vacancy-containing graphene, we also found that slip deformation followed by fracture occurs under zigzag tension. In general, tensile strength decreases as the size of cluster-type vacancies increases. However, the tensile strength of graphene with a clustered sextuple vacancy increases as the vacancy disappears because slip deformation proceeds. Furthermore, we found that slip deformation by vacancies in graphite occurs less easily than in graphene.Our results suggest that the shape of vacancies affects the strengths of graphene and graphite.
Influence of Post-annealing Temperature on the Properties of Ti-Doped In2O3 Transparent Conductive Films by DC Ratio-frequency Sputtering
Authors: Li Lei , Chen Chen , Dong Chengjun , Cao JiaJia , Dang Jingmin , Wang Yiding 
Published: September 2011

ABSTRACTIn this paper, titanium doped (2 wt. %) indium oxide (TIO) thin films deposited on quartz substrates by DC sputtering were presented. Dealt with different temperatures from 420°C to 620°C of post-annealing in vacuum for 40 minuets, the samples display different optical and electric properties. The deposited films exhibited polycrystalline in the preferred (222) and (440) orientation, with higher mobility (up to 48.6 cm2/VS) and lower resistivity (1.26 ×10-4Ω·cm) at the post-annealing temperature of 520°C. The average optical transmittance of the films is over 92% in a wavelength range from 300 to 1100 nm and the transmittance has only around 1.8% change with different post-annealing temperatures.
Mass-printed integrated circuits with enhanced performance using novel materials and concepts
Authors: Schmidt Georg C. , Bellmann Maxi , Kempa Heiko , Hambsch Mike , Reuter Kay , Stanel Michael , Hübler Arved C. 
Published: September 2011

ABSTRACTPrinted electronics is a seminal technology for the production of simple disposable electronic products. In comparison to conventional silicon electronics it offers the possibility to use potentially cheap materials (e.g. polymers) which can be processed as solutions or dispersions by means of highly productive mass printing technologies. One main aim is the production of fully mass printed electronic circuits for the identification of single items, which should not cost more than one cent per tag. For the realization several challenges have to be clarified. On the one hand the performance of the - often organic - materials has to be increased in interaction with the used printing technologies. On the other hand the printing methods themselves have to be adapted and continuously improved. Alternatively, new approaches for the preparation of structured thin films have to be developed. This paper introduces a new technique for the production of source/drain electrodes with high resolution.
Dinosaur and Crocodile Fossils from the Mesozoic of Portugal: Neutron Tomography and Synchrotron-Radiation Based Micro-Computed Tomography
Authors: Martins Rui M.S. , Beckmann Felix , Castanhinha Rui , Mateus Octávio , Klaus Pranzas Philipp 
Published: September 2011

ABSTRACTPortugal is ranked within the 10 countries with the most dinosaur taxa and the Lourinhã Formation is known by the Late Jurassic findings of dinosaurs and other fossils. In many cases, studies of the external morphological characteristics of the fossils are not sufficient to extract all the information for a paleontological study and, thus, observations of internal structures, using non-destructive techniques, are required. The fossils studied in the present work belong to the Museum of Lourinhã. The access to the Geesthacht Neutron Facility in Germany allowed us to characterize a jaw of the dinosaur Baryonyx walkeri specimen and the jaw of a crocodile (possibly a Tomistomidae) by Neutron Tomography. The study allowed us to detect the presence of teeth inside the jaws and it provides valuable information about the development of its dental characteristics. Synchrotron radiation based micro-computed tomography studies on tiny samples have been performed at the beamline HARWI II operated by the Helmholtz-Zentrum Geesthacht at the storage ring DORIS III at the Deutsches Elektronen–Synchrotron DESY in Hamburg, Germany. The first data recorded for eggshells collected in the Lourinhã Formation is shown. It allowed us to visualize the morphology of the pores and their connectivity in the eggshells, providing information that is either exceedingly difficult or impossible to obtain by traditional methods based on section cutting.
Interim Report on THE LIGHTFASTNESS CORRELATION PROJECT
Authors: Gottsegen Mark D. 
Published: September 2011

ABSTRACTThis paper describes the five-year Lightfastness Correlation Project that I am conducting in sixteen institutions in the US and Western Europe, with the support of the Samuel H. Kress Foundation.Dr. Robert L. Feller, a scientist at the National Gallery of Art, published several papers in the 1970s in which he speculated that a certain duration of time could be correlated, in a general way, to the color changes noted in the Blue Wool Textile Fading Cards. Museums use the cards as inexpensive dosimeters, put somewhere in a gallery along with the art. Enough is known about their behavior to have confidence in their ability to indicate when it is time to remove an object from exhibition.The Blue Wools are also used in two Standards developed by ASTM International’s Subcommittee D01.57 on Artists’ Paints and Related Materials. ASTM D 5383 and ASTM D 5398 are simple lightfastness test methods. In them, the Blue Wool cards are exposed to natural daylight along with any colored material, and are used to tell the artist when it’s time to stop the test and as a rating device.Another ASTM Standard from D01.57, ASTM D4303, uses instruments to control the accumulated amount of natural daylight, or simulated daylight in a xenon arc light exposure machine. It also uses a spectrophotometer to calculate the color change that can occur in a test sample, expressed in CIE L*a*b*. There is also a standard formula for calculating color change that results in a single number, expressed as Delta E, or ∆E.The ∆E number is used by ASTM D01.57 to assign lightfastness ratings to artists’ coloring materials covered by its Specifications for various products. Initial development of the ASTM methods began in 1977; we have 33 years of data that confirms the worth of the methods used in our testing.What is the relationship between the results of Blue Wool testing and the results using D01.57’s technical ∆Es? This is a fundamental question we have yet to thoroughly examine. We have begun to work on the problem, using accelerated natural and artificial light sources as in ASTM D 4303. But no one has ever tried to compare the results of these two test methods in a museum environment, over an extended period of real time.“The Lightfastness Correlation Project” ends in August 2011, and a final scientific report will be submitted to the sponsor, The Samuel H. Kress Foundation, in September 2011.
Research on the Corrosion of Bronze Weapons from the Pits of the Terracotta Warriors
Authors: Zhang Xiaomei , Yuan Sixun , Wu Yongqi , Guo Baofa , Han Jing 
Published: September 2011

ABSTRACTLarge amounts of bronze weapons have been unearthed from the pits of the Terracotta Warriors. Though they are of the same period, their condition is quite different; some are slightly corroded; some have almost no corrosion with a gray-black or green-gray surface; some are badly corroded. ICP, XRD, SEM, EDX, XRF, AES and Metalloscope were employed on seven bronze weapons to investigate their composition, structure and differences between the surfaces and bulk metals. Results showed that all these bronze weapons are high-tin bronzes. The three bronze swords contain a higher tin content than the others and have undergone heat treatment, which gives them the necessary tenacity of weapons. The surface layers of the weapons are rich in tin in various degrees because of selective corrosion and the migration of copper ions during corrosion. Some objects are more corrosion-resistant by a quenching treatment and the formation of compact tin oxides.
Divergent Pottery Firing Practices at the Advent of the Early Bronze Age: The Social Integration of Crafts and Craftspeople at Kura-Araxes Sites in the Northeastern Caucasus
Authors: Heinsch MaryFran 
Published: September 2011

ABSTRACTTwo separate pottery types, Kura-Araxes and Velikent Fine Wares can be found together at a number of Early Bronze Age sites in the Northeastern Caucasus. These ceramics are strikingly different in their appearance. Velikent Fine Ware bears indications that it may have been fired at a much higher temperature than Kura-Araxes wares. The obvious contrasts in their production raised suspicions that Velikent Fine Wares represented either an import or an intrusive production regime perhaps linked to the advent of Bronze metallurgy in this region or at least relying on a shared pyrotechnology. Prior results of Xeroradiographic analysis and INAA are merged with recent re-firing analysis to examine these hypotheses. The findings suggest that while a specific link between metal and pottery production cannot be confirmed, the emergence of divergent firing practices within an otherwise unified production tradition speaks to complex relationships between craftspeople within Early Bronze Age communities in the Caucasus.
Poly-Si Thin Film Formation Using a Novel Low Thermal Budget Process
Authors: Zhu Minghao , Kuo Yue , Lin Chen-Han , Wang Qi 
Published: September 2011

ABSTRACTPolycrystalline silicon thin films were formed from the amorphous silicon thin film by the pulsed rapid thermal annealing process enhanced with a thin nickel seed layer through the vertical crystallization mechanism. In this paper, authors presented the results on the material properties of the crystallized film. The dopant and film thickness effects were also investigated. It has been demonstrated that a 2 μm thick amorphous silicon n+-i-p+ diode structure could be transformed into polycrystalline stack with a 4-pulse 1 sec 850°C heating and 5 sec cooling cycle process.
Voc Saturation Effect in High-temperature Hydrogenated Polycrystalline Silicon Thin-film Solar Cells
Authors: Hidayat Hidayat , Widenborg Per I. , Aberle Armin G. 
Published: September 2011

ABSTRACTHydrogenation of polycrystalline silicon thin-film solar cells is performed to improve the one-sun open-circuit voltage (Voc) of the device. Voc is found to increase linearly with increasing hydrogenation temperature and then saturates. For planar and textured samples, the Voc saturates at about 340 ºC and 307 ºC respectively. The low hydrogenation temperature helps to lower thermal budget during industrial process. Arrhenius plot of Voc prior to the saturation shows that the textured samples have lower activation energies than the planar sample. The activation energies of samples 188 (planar), 788 (textured) and 888 (textured) are 1.31 eV, 0.86 eV and 0.92 eV, respectively. The lower activation energies of the textured samples could be due to the shorter diffusion thickness and the increased surface area that is exposed to the hydrogen plasma.
11.0% Stable Efficiency on Large Area, Encapsulated a-Si:H and a-SiGe:H based Multijunction Solar Cells Using HF Technology
Authors: Banerjee A. , Beglau D. , Su T. , Pietka G. , Yue G. , Yan B. , Yang J. , Guha S. 
Published: September 2011

ABSTRACTWe report on the investigation of large area a-Si:H/a-SiGe:H double-junction and a-Si:H/a-SiGe:H/a-SiGe:H triple-junction solar cells prepared by our proprietary High Frequency (HF) glow discharge technique. For investigative purposes, we initially used the simpler double-junction structure. We studied the effect of: (1) Ge content, (2) cell thickness, and (3) SiH4 and GeH4 gas flow on the light-induced degradation of the solar cells. Our results show that the double-junction cells with different Ge concentration have open-circuit voltage (Voc) in the range of 1.62-1.75 V. Voc exhibits a flat plateau in the range of 1.65-1.72 V for both initial and stabilized states. The light-induced degradation for cells in this range of Voc is insensitive to the Ge content. In terms of thickness dependence of the intrinsic layers, we found that the initial efficiency increases with cell thickness in the thickness range 2000-4000 Å. However, light-induced degradation increases with increasing thickness. Consequently, the stabilized efficiency is invariant with cell thickness in the thickness range studied. The results of SiH4 and GeH4 gas flow on cell characteristics demonstrate that the deposition rate decreases by only 20% when the active gas flow is reduced to 0.25 times standard flow. The initial and stabilized efficiencies are similar. The information gleaned from the study was used to fabricate high efficiency, large area (~464 cm2) double- and triple-junction solar cells. The highest stable efficiency, as measured by NREL, was 9.8% and 11.0% for the double- and triple-junction structures, respectively.
Sliver Solar Cell Technology: Pushing the Material Boundaries
Authors: Franklin Evan , Blakers Andrew , Weber Klaus , Everet Vernie 
Published: September 2011

ABSTRACTOne of the primary objectives of the global photovoltaic research community is to effect significant manufacturing cost reductions, either by reducing material and processing costs or by increasing solar cell efficiency. One very promising technology for achieving both of these goals is Sliver technology, which offers potential for a 10- to 20-fold reduction in the consumption of purified silicon, while at the same time achieving very high cell efficiencies by fully exploiting the advantages of mono-crystalline silicon.Sliver solar cells are thin, mono-crystalline silicon solar cells fabricated using a combination of micro-machining techniques and standard silicon device fabrication technologies. Rather than fabricating a single solar cell on the surface of a wafer, many hundreds to several thousand individual Sliver solar cells are fabricated within a single wafer. The dimensions of a Sliver cell depend upon wafer size, wafer thickness, and the micro-machining method employed.Cells typically have a length of 5 – 12cm, a width of 0.5 – 2mm, and a thickness of 20 – 60 micron. 20% efficient Sliver solar cells using standard cell processing methods and a robust processing sequence, have been fabricated at ANU. Current research efforts are directed towards developing and establishing new fabrication techniques to further simplify the fabrication sequence and to improve cell efficiency.This paper presents an overview of Sliver technology. The fabrication method and some key challenges in producing Sliver cells is presented along with the measured performance of cells fabricated in the ANU solar research laboratory.
Band energy structure arrangement for organic solar cells with metalized deoxyribonucleic acid strands on anode electrode
Authors: Guvenc Ali Bilge , Guo Shirui , Ozkan Cengiz , Ozkan Mihrimah 
Published: September 2011

ABSTRACTDeoxyribonucleic acids provide exciting opportunities as templates in self assembled architectures and functionality in terms of optical and electronic properties. In this study, we investigate the effects of metalized DNA sequences in organic bulk-heterojunction solar cells. These effects are characterized via optical, quantum efficiency and current-voltage measurements. We demonstrated that by arranging the band energy structure of the devices via placing metalized deoxyribonucleic acid sequences on the hole collection side of the active layer lead to a 20% increase in the power conversion efficiency.