bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of high crystalline p /i interface layer on the performance of microcrystalline silicon solar cells deposited in a single‐chamber system
Authors: Zhang X. D. , Sun F. H. , Wang G. H. , Xu S. Z. , Wei C. C. , Hou G. F. , Sun J. , Xiong S. Z. , Geng X. H. , Zhao Y. 
Published: January 2010

AbstractWe studied boron (B) contaminations at the p /i interface in hydrogenated microcrystalline silicon (μc‐Si:H) p ‐i ‐n solar cells deposited in a single chamber system. We used secondary ion mass spectroscopy to measure B depth profiles in μc‐Si:H thin films with different crystalline volume fraction (Xc) and found that μc‐Si:H films with a higher Xc showed a less boron contamination than that with a lower Xc in the amorphous/microcrystalline transition region. Based on this result, we proposed an interface layer with a suitable high Xc inserted between p and i layers to reduce the contaminations and then improve the performance of μc‐Si:H solar cells prepared in the single‐chamber system. The solar cell experiments indeed showed that a suitable high Xc interface layer decreased the boron contaminations at the p /i interface. The solar cell efficiency was increased with an enhanced short wavelength response. Combined with the optimized high Xc interface layer, the high quality μc‐Si:H, and the light trapping effect of front electrode, a single‐junction μc‐Si:H solar cell with 6.3% (1.0 cm2) of conversion efficiency was made in the single‐chamber system. Using the improved μc‐Si:H solar cell as the bottom cell, we achieved a 10.05% (1.0 cm2) efficiency for an a‐Si:H/μc‐Si:H tandem solar cell (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new method used to control the structure of high rate microcrystalline silicon thin films
Authors: Zhang X. D. , Zhang H. , Yue Q. , Wei C. C. , Sun J. , Hou G. F. , Xiong S. Z. , Geng X. H. , Zhao Y. 
Published: January 2010

AbstractWe report a systematic study of plasma heating effect on microcrystalline silicon (μc‐Si:H) deposition. Normally, substrate surface temperature increases with time during a high rate deposition of μc‐Si:H thin film, especially under a high power and high pressure condition. We deposited μc‐Si:H films using a very high frequency discharge under the high pressure and high power condition at a fixed heater temperature or a profiled heater temperature. Raman spectra with different wavelength excitations showed that a proper heater temperature profiling during μc‐Si:H deposition is an effective method to modify the structure of μc‐Si:H films, which can control the structure evolution to form a uniform crystallinity along the growth direction and reduce the amorphous incubation layer thickness (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
B‐doped a‐Si:H contact improvement on silicon heterojunction solar cells and interdigitated back contact structure
Authors: Desrues T. , Ribeyron P.‐J. , Vandeneynde A. , Ozanne A.‐S. , Souche F. , Muñoz D. , Denis C. , Diouf D. , Kleider J.‐P. 
Published: January 2010

AbstractThis study reports on the p‐type a‐Si:H emitter layer of silicon heterojunction (Si‐HJ) solar cells and its contacting scheme. The influence of the ratio between p‐type a‐Si:H emitter width and its contact width is checked on Interdigitated Back Contact (IBC) Si‐HJ both experimentally and by 2D modelling. A low emitter contact fraction value is found to be detrimental to the IBC Si‐HJ cells efficiency due to distributed series resistance effects. This not only limits the cell fill factor (FF) but also its short circuit current density (Jsc). By increasing the emitter contact fraction an efficiency of 12.7% is obtained on 25 cm2 IBC Si‐HJ solar cells. New B‐doped a‐Si:H emitter layers and contacts are also developed on inverted Si‐HJ cells. Depending on the a‐Si:H conductivity, we observe a great impact of the contact material on Si‐HJ cells performance (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aluminum doped silicon‐carbon alloys prepared by hot wire chemical vapor deposition
Authors: Chen T. , Schmalen A. , Wolff J. , Yang D. , Carius R. , Finger F. 
Published: January 2010

AbstractAluminum doped stoichiometric microcrystalline silicon carbide (µc‐SiC:H) thin films deposited by Hot Wire Chemical Vapor Deposition (HWCVD) technique have been studied. Without Al‐doping, highly crystalline µc‐SiC:H thin films prepared from monomethysilane (MMS) and hydrogen are mainly cubic polytype and are unintentionally doped into n‐type. Trimethyaluminum (TMAl) is used as a source of Aluminum. By increasing the TMAl/MMS ratio (rdoping), the dark conductivity of µc‐SiC:H thin film firstly decreases and then increases. This variation indicates the compensation from n‐type to p‐type, which is confirmed by the thermo‐power measurements. It is observed in the infrared spectra that the crystallinity of µc‐SiC:H thin film deceases with increasing rdoping. In order to improve the crystallinity of this conductive p‐type µc‐SiC:H thin film, the effect of deposition pressure (pdepo) has been investigated. With increasing pdepo, the crystallinity is improved and the structure of SiC alloys changes according to the Raman spectra. A maximum dark conductivity of 1.3×10–1 S/cm has been achieved at rdoping = 0.0620 and pdepo = 100 Pa. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new luminescent defect state in low temperature grown amorphous SiNxOy thin films
Authors: Dong Hengping , Chen Kunji , Wang Danqing , Li Wei , Ma Zhongyuan , Xu Jun , Huang Xinfan 
Published: January 2010

AbstractWe reported the observation of photoluminescence (PL) from low‐temperature grown amorphous silicon oxynitride (a‐SiNxOy) films with its peak location tunable in a wide range from 450 to 600 nm by controlling the Si/N ratios. The origin of luminescence from a‐SiNxOy film has been thoroughly investigated. From the results of the optical absorbance spectrum, an oxygen‐induced new luminescent defect state, which was characterized to be responsible for the light emission, was determined to locate at about 0.65 eV from the absorption edge. The measurements of Fourier transform infrared (FTIR) spectra and X‐ray photoelectron spectrum (XPS) has verified the existence of O‐Si‐N bonding configuration, which serves as this new luminescent defect state in this kind of material (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectral selectivity constraints in fluo‐ rescence detection of biomolecules using amorphous silicon based detectors
Authors: Conde J. P. , Jóskowiak A. , Lipovšek B. , Pimentel A. , Pereira A. T. , Santos M. , Krč J. , Topic M. , Prazeres D. M. F. , Chu V. 
Published: January 2010

AbstractA microdevice based on a thin‐film hydrogenated amorphous silicon (a ‐Si:H) p‐i‐n photodiode is used to quantify the density of DNA oligonucleotides labelled with a fluorophore and the density of E. coli cells expressing GFP (green fluorescent protein) by fluorescence. An absorption filter is integrated in the device which filters the excitation light and transmits the emitted light to the photodetector. This filter is an amorphous silicon carbon (a‐SiC:H) alloy in which the bandgap can be selected according to the excitation and emission wavelengths of the fluorophores used by varying the carbon content of the film. Control of the thickness of the a‐SiC:H film allows the modulation of the transmission ratio between the excitation wavelength and the emission wavelength. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Imaging ferroelectric domains in multiferroics using a low‐energy electron microscope in the mirror operation mode
Authors: Cherifi Salia , Hertel Riccardo , Fusil Stéphane , Béa Hélène , Bouzehouane Karim , Allibe Julie , Bibes Manuel , Barthélémy Agnès 
Published: January 2010

AbstractWe report on low‐energy electron microscopy imaging of ferroelectric domains with submicron resolution. Periodic strips of ‘up’ and ‘down’‐polarized ferroelectric domains in bismuth ferrite – a room temperature multiferroic – serve as a model system to compare low‐energy electron microscopy with the established piezoresponse force microscopy. The results confirm the possibility of full‐field imaging of ferroelectric domains with short acquisition times by exploiting the sensitivity of ultraslow electrons to small variations of the electric potential near surfaces in the “mirror” operation mode.magnified image(© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation on (Sr,Co)Bi2Nb2O9 thin films: A lead‐free room temperature multiferroics
Authors: Kumar Ashok , Collazo Bryan , Sánchez Dilsom , Katiyar R. S. 
Published: January 2010

AbstractNovel room temperature single phase multiferroic 10% Co doped SrBi2Nb2O9 (SCBN) thin films were fabricated on Pt/Ti/SiO2/Si(100) substrate by pulse laser deposition. The surface morphology indicates homogeneous grains with average grain size and surface roughness of ∼40–130 nm and 6 nm, respectively. High dielectric constant, low dielectric loss <2–5%, negligible frequency independent conductivity, moderate polarization, frequency dependent coercive field, and weak saturation magnetization were observed. The change in the shape of magnetic hysteresis and values of coercive field along in‐plane and out‐of‐plane M–H hysteresis indicates a magnetic anisotropy. The presence of magnetic moments and electric dipole in the same plane suggest mutual cooperation between electric and magnetic ordering on the mesoscopic and microscopic scale. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient spectrally dynamic blue‐to‐green emission of bipyridine‐based bridged silsesquioxanes for solid‐state lighting
Authors: Nobre Sónia S. , Cattoën Xavier , Ferreira Rute A. S. , Man Michel Wong Chi , Carlos Luis D. 
Published: January 2010

AbstractWe report a metal‐free bpy‐bridged silsesquioxane displaying an efficient and tuneable blue‐to‐green emission (maximum quantum yield and luminance values of 0.22 ± 0.02 cd m–2 and 63 ± 3 cd m–2, respectively) when excited by commercial InGaN light emitting diodes (LEDs) (385–405 nm). This is the highest quantum yield value reported so far for metal‐free phosphors easily excited by commercial InGaN long‐UV/blue LEDs bringing organic/inorganic hybrids on the way to applications as metal‐free phosphors for smart LED‐based lighting and LED‐addressed displays. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Milliwatt power AlGaN‐based deep ultraviolet light emitting diodes by plasma‐assisted molecular beam epitaxy
Authors: Liao Yitao , Thomidis Christos , Kao Chen‐kai , Moldawer Adam , Zhang Wei , Chang Yi‐chung , Nikiforov A. Yu. , Bellotti Enrico , Moustakas Theodore D. 
Published: January 2010

AbstractWe report the development of AlGaN‐based deep ultraviolet LEDs by plasma‐assisted molecular beam epitaxy. The devices were evaluated under bare‐die configuration, placed outside an integrated sphere, and were found to have optical power of 1.3 mW and 1.2 mW at 300 nm and 277 nm, under pulsed driving current of 200 mA and 500 mA, respectively. The external quantum efficiency (EQE) of the 300 nm LED is 0.16% at drive current of 90 mA. These data suggest that AlGaN alloys grown by MBE under excess Ga are capable of producing deep UV‐LEDs with high IQE. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conductance through a redox system in the Coulomb blockade regime: Many‐particle effects and influence of electronic correlations
Authors: Tornow Sabine , Zwicknagl Gertrud 
Published: January 2010

AbstractWe investigate the transport characteristics of a redox system weakly coupled to leads in the Coulomb blockade regime. The redox system comprises a donor and acceptor separated by an insulating bridge in a solution. It is modeled by a two‐site extended Hubbard model which includes on‐site and inter‐site Coulomb interactions and the coupling to a bosonic bath. The current–voltage characteristics is calculated at high temperatures using a rate equation approach. For high voltages exceeding the Coulomb repulsion at the donor site the calculated transport characteristics exhibit pronounced deviations from the behavior expected from single‐electron transport. Depending on the relative sizes of the effective on‐site and inter‐site Coulomb interactions on one side and the reorganization energy on the other side we find either negative differential resistance or current enhancement.magnified imageSchematic view of the redox system with donor (D) and acceptor (A) coupled to the leads L and R. The electronic degrees of freedom of the DA system are coupled to the environment comprising internal vibrations and the solvent dynamics. The current is calculated as a function of the bias voltage Vb and gate voltage Vg.(© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of unstratified and centre‐stratified randomization in multi‐centre clinical trials
Authors: Anisimov Vladimir V. 
Published: January 2010

AbstractThis paper deals with the analysis of randomization effects in multi‐centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre‐stratified block‐permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated.A new analytic approach using a Poisson‐gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed‐form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre‐stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Hydropyrolysis over a platinum catalyst as a preparative technique for the compound‐specific carbon isotope ratio measurement of C27 steroids
Authors: Meredith Will , Gomes Rachel L. , Cooper Mick , Snape Colin E. , Sephton Mark A. 
Published: January 2010

AbstractCompound‐specific stable carbon isotope analysis by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is an important method for the determination of the 13C/12C ratios of biomolecules such as steroids, for a wide range of applications. However, steroids in their natural form exhibit poor chromatographic resolution, while derivatisation adds carbon thereby corrupting the stable isotopic composition. Hydropyrolysis with a sulphided molybdenum catalyst has been shown to defunctionalise the steroids, while leaving their carbon skeleton intact, allowing for the accurate measurement of carbon isotope ratios. The presence of double bonds in unsaturated steroids such as cholesterol resulted in significant rearrangement of the products, but replacing the original catalyst system with one of platinum results in higher conversions and far greater selectivity. The improved chromatographic performance of the products should allow GC/C/IRMS to be applied to more structurally complex steroid hormones and their metabolites. Copyright © 2010 John Wiley & Sons, Ltd.
Measurement at the field scale of soil δ13C and δ15N under improved grassland
Authors: Dixon E. R. , Blackwell M. S. A. , Dhanoa M. S. , Berryman Z. , Martinez N. de la Fuente , Junquera D. , Martinez A. , Murray P. J. , Kemp H. F. , Meier‐Augenstein W. , Duffy A. , Bol R. 
Published: January 2010

AbstractVariations in natural abundance of carbon (C) and nitrogen (N) stable isotopes are widely used as tools for many aspects of scientific research. By examining variations in the ratios of heavy to light stable isotopes, information can be obtained as to what physical, chemical and biological processes may be occurring. The spatial heterogeneity of soil δ15N‐ and δ13C‐values across a range of scales and under different land use have been described by a number of researchers and the natural abundances of the C and N stable isotopes in soils have been found to be correlated with many factors including hydrology, topography, land use, vegetation cover and climate. In this study the Latin square sampling +1 (LSS+1) sampling method was compared with a simple grid sampling approach for δ13C and δ15N measurement at the field scale. A set of 144 samples was collected and analysed for δ15N and δ13C from a 12 × 12 grid (in a 1 ha improved grassland field in south‐west England). The dimension of each cell of the grid was approximately 11 × 6 m. The 12 × 12 grid was divided into four 6 × 6 grids and the LSS+1 sampling technique was applied to these and the main 12 × 12 grid for a comparison of sample means and variation. The LSS+1 means from the 12 × 12 grid and the four 6 × 6 grids compared well with the overall grid mean because of the low variation within the field. The LSS+1 strategy (13 samples) generated representative samples from the 12 × 12 grid, and hence would be an acceptable method for sampling similar plots for the measurement of mean isotopic composition. Copyright © 2010 John Wiley & Sons, Ltd.
Movement of newly assimilated 13C carbon in the grass Lolium perenne and its incorporation into rhizosphere microbial DNA
Authors: Clayton S. J. , Clegg C. D. , Bristow A. W. , Gregory P. J. , Headon D. M. , Murray P. J. 
Published: January 2010

AbstractOne of the key processes that drives rhizosphere microbial activity is the exudation of soluble organic carbon (C) by plant roots. We describe an experiment designed to determine the impact of defoliation on the partitioning and movement of C in grass (Lolium perenne L.), soil and grass‐sterile sand microcosms, using a 13CO2 pulse‐labelling method. The pulse‐derived 13C in the shoots declined over time, but that of the roots remained stable throughout the experiment. There were peaks in the atom% 13C of rhizosphere CO2 in the first few hours after labelling probably due to root respiration, and again at around 100 h. The second peak was only seen in the soil microcosms and not in those with sterilised sand as the growth medium, indicating possible microbial activity. Incorporation of the 13C label into the microbial biomass increased at 100 h when incorporation into replicating cells, as indicated by the amounts of the label in the microbial DNA, started to increase. These results indicate that the rhizosphere environment is conducive to bacterial growth and replication. The results also show that defoliation had no impact on the pattern of movement of 13C from plant roots into the microbial population in the rhizosphere. Copyright © 2010 John Wiley & Sons, Ltd.
Quantification of alkylresorcinols in human plasma by liquid chromatography/tandem mass spectrometry
Authors: Ross Alastair B. , Redeuil Karine , Vigo Mario , Rezzi Serge , Nagy Kornél 
Published: January 2010

AbstractAlkylresorcinols (AR) are of interest as biomarkers of wholegrain wheat and rye intake in epidemiological studies and are currently mainly measured by gas chromatography/mass spectrometry (GC/MS) after labour‐intensive sample preparation including liquid‐liquid extraction, solid‐phase extraction (SPE) and chemical derivatization. This manuscript describes and validates an alternative approach based on normal‐phase liquid chromatography/tandem mass spectrometry for the quantification of alkylresorcinols in human plasma. The method requires neither SPE nor chemical derivatization and has a shortened run time compared to GC/MS. Normal‐ and reversed‐phase columns and various mobile phases were evaluated with and without previous SPE of the samples. Normal‐phase chromatography allowed separation of AR from the interfering triacylglycerols, diacylglycerols and sterols and enabled detection of AR even without SPE of the samples. The described method has instrumental lower limits of detection in the 25–75 pg range, and lower limits of quantification in the 75–250 pg range. Pooled human plasma and 2H4‐nonadecylresorcinol (internal standard) was applied to calibrate the method in the 20–12 000 nM range. The overall method showed intra‐batch precision of 8.6% and an averaged accuracy of 100.2%. Applications for diverse human plasma samples are presented and are compared with the results determined by GC/MS. Based on the presented data; this method requiring less sample preparation is suggested for further evaluation as an alternative to GC/MS for analysis of biomarkers of wholegrain wheat and rye intake in epidemiological studies. Copyright © 2010 John Wiley & Sons, Ltd.
The implementation of an integrated computer‐assisted system for minimally invasive cardiac surgery
Authors: Cai Junfeng , Luo Zhe , Gu Lixu , Xu Rong , Zhao Qiang 
Published: January 2010

AbstractBackgroundPreoperative planning and surgical navigation are two crucial aspects of a computer‐assisted system for the success of minimally invasive cardiac surgery.MethodsIn the first part, port placement planning was mainly discussed. We proposed an algorithm based on four criteria to achieve optimized placement. In the second part, an optical tracker was used to locate the thoracoscope and surgical instruments accurately and to show the relative positions between the thoracoscope, surgical instruments and the patient's anatomical structures. An image‐matching technique was employed to help the surgeon locate the target, using real‐time thoracoscopic video images during the procedure.ResultsIn order to verify our proposed algorithms, several clinical planning cases were performed to compare our port placement algorithm to the traditional method. Both phantom test and animal study experiments were also done to demonstrate the validity of the target tracking of the system. Both the phantom test and the animal study revealed that the fiducial registration error (FRE) was 1.08 ± 0.16 mm and system error was 5.05 ± 0.67 mm, respectively.ConclusionA novel computer‐assisted system for minimally invasive cardiac surgery has been developed. This method has shown its capability to achieve the preoperative planning and real‐time surgery navigation. Copyright © 2010 John Wiley & Sons, Ltd.
Network delay inference from additive metrics
Authors: Bhamidi Shankar , Rajagopal Ram , Roch Sébastien 
Published: January 2010

AbstractWe use computational phylogenetic techniques to solve a central problem in inferential network monitoring. More precisely, we design a novel algorithm for multicast‐based delay inference, that is, the problem of reconstructing delay characteristics of a network from end‐to‐end delay measurements on network paths. Our inference algorithm is based on additive metric techniques used in phylogenetics. It runs in polynomial time and requires a sample of size only poly(logn). We also show how to recover the topology of the routing tree. © 2010 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Konstruktiver Glasbau – auf Distanz
Authors: Knaack Ulrich , Techen Holger 
Published: January 2010

AbstractWas ist passiert in den letzten Jahren des Konstruktiven Glasbaus? Wir haben uns mit Details beschäftigt sowie Berechnungsverfahren entwickelt, von denen allerdings selbst die Entwickler sagen, dass sie für eine Praxisanwendung zu komplex sind. Wir haben eine nicht unerhebliche Zahl von innovativen Projekten verwirklicht, die in ihrer Summe eine Evolutionskette der Entwicklung darstellen und weiteres Potential erwarteten lassen. Die Frage ist nur, wo dieses Potential liegt – ob tatsächlich in noch mehr verfeinerten Details oder grundsätzlich anderen Herangehensweisen an die Konstruktion und das Material Glas. Dieser Frage versucht der hier vorliegende Artikel zu folgen und möchte Richtungen aufzeigen, die jenseits der bereits eingeschlagenen Wege liegen und Potentiale bieten, um die nächsten Evolutionsschritte zu erreichen.