bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical characterisation of aluminium nitride as antireflective coating by a new remote plasma deposition system
Authors: Claudio G. , Kaminski P. , Bass K. 
Published: November 2009

AbstractHigh bandgap materials have recently attract a lot of interest for their potential application in photovoltaics (PV). Aluminium nitride (AlN)) is a potential candidate for passivation and antireflective coating in silicon solar cells. AlN thin films have been deposited by a new remote plasma deposition system HiTUS (High Target Utilisation Sputtering). The AlN thin films are grown by reactive sputtering from an aluminium target in an N2 atmosphere, negating the use of silane gas commonly used in PECVD method. PC1D simulations have been performed to calculate the best thickness for antireflection and passivation of silicon wafers. Several depositions have been performed at different substrate temperatures. Photoconductive measurements by a WCT‐100 were performed on silicon wafer after each thermal process to measure the effective lifetime of p‐type crystalline silicon wafer boron doped <100> to measure the effective lifetime of the minority carriers. Reflectance and transmission measurements were performed for sample at different bias and flow gas ratio. Results shows that a complete transmission with a reflection of less than 5% occurs for samples with a thickness of 50 nm. An increase in carrier lifetime has been observed for AlN deposited at high temperature. Lifetime has increased in wafer annealed at 300 °C up to 15 μs suggesting the potential of AlN for silicon passivation and an alternative antireflective coating to silicon nitride. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tunneling current in gate dielectric stack in sub‐45 nanometer CMOS devices
Authors: Tyagi Hitender Kumar , Prasad B. , George P. J. 
Published: November 2009

AbstractDirect tunneling current through dual layer SiO2/high‐K dielectric structures are investigated for substrate injection. Correlation of dielectric constants and band offsets with respect to silicon has been taken into consideration in order to identify possible materials to construct these devices. The direct tunneling current in oxide/high‐K dielectric structures with equivalent oxide thickness (EOT) of 2.0 nm can be significantly lower than that through single layer oxides of the same thickness. Various structures and materials of high‐K stacks of interest have been examined and compared to access the reduction of gate current in these structures. It is estimated that HfO2/SiO2 dual stack structure can reduce gate leakage current by four orders of magnitude as compared with pure SiO2 layer of same EOT. The importance of interfacial layer in dual stack structure is high‐lighted for the reduction of gate leakage current. The present approach is capable of modeling high‐K stack structures consisting of multiple layers of different dielectrics (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boron‐ and stoichiometry‐related defect engineering during B2O3‐free GaAs crystal growth
Authors: Kiessling F.‐M. , Albrecht M. , Irmscher K. , Roßberg M. , Rudolph P. , Ulrici W. , Fornari R. 
Published: November 2009

AbstractGaAs crystals have been grown without B2O3 encapsulation by the vapour‐pressure controlled Czochralski (VCz) method to reduce undesired boron incorporation and to enable in situ control of the Ga/As ratio in the melt. With increasing Ga content of the melt the omnipresent As precipitate concentration decreases in as‐grown GaAs crystals. Semiinsulating (SI) GaAs crystals could been obtained even from melts with a composition of 46 at.% As. Comparative cathodoluminescence (CL) measurements on those crystals and on boron‐contaminated GaAs show that the luminescence bands at 1.316 eV and at 1.441 eV are related to BAs. Reduced concentrations of boron and EL2 result in significant lower near‐band edge absorption, mainly caused by the photoionization cross section of As antisites in SI GaAs. These VCz GaAs crystals possess improved optical properties. Semi‐conducting (SC) GaAs:Si crystals were grown from near‐stoichiometric melts. Positron annihilation lifetime spectroscopy measurements show that the low boron concentration in our SC VCz GaAs results always in 3 times higher Ga vacancy concentrations compared to standard SC GaAs. CL bands due to optical transitions at 0.95 eV and 1.15 eV are related to auto‐compensating (VGaSiGa)2‐ and (SiGaVGaSiGa)– complexes, respectively, and depend on the doping level. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nature of vacancy defect clusters in chalcogenic semiconductors of AIIBVI group irradiated by neutrons
Authors: Davidyuk G. Y. , Bozhko V. V. , Myronchuk G. L. , Kevchin A. G. , Kažukauskas V. 
Published: November 2009

AbstractAn experimentally proven model is proposed stating that vacancies of cadmium atoms are dominating in kernels of the defect clusters (DCs) formed in single CdS crystals by the irradiation with fast 1 MeV reactor neutrons. The so‐called subthreshold effects play the essential role in cluster formation. The subthreshold effects consequently lead to the excitation and ionization of the K‐shell of Cd atoms followed by an increase of charge of Cd ions. This finally result in an ejection of these ions from the kernels to periphery of DCs due to the electrostatic force (electrostatic explosion). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge spectroscopy of Si nanocrystals in a SiO2 matrix
Authors: Antonova Irina , Neustroev Efim , Smagulova Svetlana , Jedrzejewski Jedrzej 
Published: November 2009

AbstractFor the first time, the recharging of semiconductor nanocrystals (NCs) embedded in a dielectric matrix was studied by means of charge deep‐level transient spectroscopy (Q‐DLTS). Our measured Q‐DLTS spectra were found to arise from two or three transient processes with different activation energies observed in different temperature ranges. We suggest that these are associated with quantum‐confined electronic states in Si NCs. The data obtained were used to extract the energy position of NC levels, the size of NCs, and the typical recharging times of weakly coupled NCs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermo‐optical investigations of NaNbO3 thin films by spectral ellipsometry
Authors: Aulika Ilze , Dejneka Alexandr , Lynnyk Anna , Zauls Vismants , Kundzins Maris 
Published: November 2009

AbstractIn this work a spectroscopic ellipsometry was applied to the thermo‐optical investigations of sodium niobate NaNbO3 (NN) thin films at the wide temperature range of 5–820 K. The temperature dependence of complex refractive index dispersions and optical bang energy of the direct allowed electron transitions were evaluated. Additionally dynamic scans of the main ellipsometric angles at the several fixed wave lengths of 300, 400, 500 and 635 nm were performed to acquire more detailed temperature dependences of the refractive index and extinction coefficient. Pronounced minima/maxima and substantial jumps in the temperature dependence of complex refractive index and band gap energy were found and corresponded to the structural phase transition temperatures of NN single crystals and ceramics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
QSPR Study on the Melting Points of a Diverse Set of Potential Ionic Liquids by Projection Pursuit Regression
Authors: Ren Yueying , Qin Jin , Liu Huanxiang , Yao Xiaojun , Liu Mancang 
Published: November 2009

AbstractA Quantitative Structure–Property Relationship (QSPR) study was carried out to model the melting points for a diverse set of 288 potential Ionic Liquids (ILs) including pyridinium bromides, imidazolium bromides, benzimidazolium bromides, and 1‐substituted 4‐amino‐1,2,4‐triazolium bromides. Based on the calculated descriptors by CODESSA program, a Principal Component Analysis (PCA) was performed on the whole data to detect the homogeneities in the dataset and to assist the separation of the data into representative training and test sets. Heuristic Method (HM) and Projection Pursuit Regression (PPR) were used to develop linear and nonlinear models between the descriptors and the melting points. The PPR model gave a high predictive correlation coefficient (R2) of 0.810 and an Average of Absolute Relative Deviation (AARD) of 17.75%, which are better than those by HM model (R2=0.712, AARD=24.33%) indicating that PPR is better for the prediction of the melting points. In addition, the descriptors selected by HM can give some insight into factors that can affect the melting points, i.e., benzene ring structure, rotatable bonds, branching, symmetry, and intramolecular electronic effects. This information would be very useful in the design of the potential ILs with desired melting points.
Hybrid single frequency network propagation channel sounding and antenna diversity measurements
Authors: Lacoste Frédéric , Scot Gaël , Ros Benjamin , Pajusco Patrice , Conrat Jean Marc , Perez Fontan Fernando 
Published: November 2009

AbstractDuring the last decade, several land mobile communication networks have been developed based on full satellite solutions such as Globalstar or Iridium systems or on huge terrestrial networks such as GSM for example. Deploying new terrestrial networks or new satellite constellations for new telecommunication or broadcast mobile systems on very large areas would be so expensive that another solution is now often considered: hybrid systems with a terrestrial segment to cover high‐density built‐up areas and a satellite segment to bring services to the largest part of coverage area. In the framework of Satellite Digital Multimedia Broadcasting CNES project, such a hybrid mobile broadcast system was studied, in particular air interface performances. This performance assessment required a good knowledge of the hybrid single frequency network (SFN) propagation channel including a geostationary satellite and terrestrial gap fillers. The requirement for an exhaustive characterization of the hybrid SFN propagation channel involved the development of a specific channel sounding solution. Moreover, mobile telecommunication systems recently developed use spatial diversity techniques to take benefit from multipath spatial decorrelation in particular. The measurement of diversity gains in actual conditions can provide information very helpful for network deployment and air interface design. The CNES channel sounder enables to carry out such diversity measurements using only propagation data. This paper presents this channel sounder developed and used to measure the SFN radio propagation channel with four transmitters in spatial diversity configuration. Copyright © 2009 John Wiley & Sons, Ltd.
Phosphorylation of Corn Starch in an Ionic Liquid
Authors: Xie Wenlei , Shao Li 
Published: November 2009

AbstractCorn starch was phosphorylated by reaction with sodium dihydrogenphosphate or disodium hydrogenphosphate using 1‐butyl‐3‐methylimidazolium chloride (BMIMCl) as reaction medium. The parameters varied included the molar ratio of reactant, reaction time and temperature and were investigated regarding the degree of substitution for the phosphorylated starch. The degree of substitution of starch phosphates prepared ranged from 0.03 to 0.55. The product was characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM) and X‐ray diffraction (XRD) techniques. It was found that the native crystallinity of corn starch was largely distroyed during the dissolution and functionalization process in the ionic liquid system under the reaction conditions.
Characterization of the Pasting, Flow and Rheological Properties of Native and Phosphorylated Rice Starches
Authors: Lin Qinlu , Xiao Huaxi , Zhao Jian , Li Lihui , Yu Fengxiang 
Published: November 2009

AbstractPhosphorylation of rice starch and its effects on the physiochemical properties of the starch were investigated. Phosphorylation was conducted using the oven heating method by heating mixtures of rice starch and monosodium dihydrogenphosphate at 120‐150°C for 0.5‐2 h, and the pasting, flow and rheological properties of the resulting starch phosphates were analyzed. Phosphorylation with substitution degrees of up to 0.12 was achieved by raising the reaction temperature to 140°C, but further increase in the temperature to 150°C caused a marked reduction in the degree of substitution. Phosphorylation resulted in significant declines in pasting temperature and setback, but increases in peak viscosity and breakdown. Suspensions of rice native starch and starch phosphates were shown to be non‐Newtonian, pseudoplastic fluids, exhibiting typical shear thinning. They also exhibited yield stress, the magnitude of which increased with the degree of phosphate substitution. Dynamic testing showed that phosphorylation resulted in a decrease in the temperature at which storage and loss moduli (G′ and G″) reached a peak during heating and a reduction in G′ during cooling. These results appeared to indicate that phosphorylation improved the shear stability of rice starch pastes and enhanced swelling of starch granules, but impeded starch retrogradation.
α‐methylene‐γ‐butyrolactones: versatile skin bioactive natural products
Authors: Lepoittevin Jean‐Pierre , Berl Valérie , Giménez‐Arnau Elena 
Published: November 2009

AbstractNatural products containing an α‐methylene‐γ‐butyrolactone moiety, mainly of the sesquiterpene type, are widely observed in plants, which upon coming into contact with skin, will induce major skin toxicological side effects or phytodermatitis. Indeed two main dermatological pathologies have been associated with a skin exposure to molecules containing an α‐methylene‐γ‐butyrolactone moiety: allergic contact dermatitis (ACD) and chronic actinic dermatitis (CAD). ACD is an immunologically based disease resulting from modifications of epidermal proteins by sensitizers or haptens. Indeed, α‐methylene‐γ‐butyrolactones are highly electrophilic structures that can act as Michael acceptors towards nucleophilic residues of proteins. Cysteine and lysine are the most modified residues leading, in the case of enantiomerically pure lactones, to the formation of diastereomeric adducts. This chemical enantioselectivity induces an enantiospecificity of the allergic reaction, i.e., an individual sensitized to one enantiomer will not develop clinical symptoms when exposed to the other enantiomer and vice versa. Sesquiterpene lactones have been also associated with another pathology that involves UV irradiation and DNA modifications. Interestingly, it was found that α‐methylene‐γ‐butyrolactones, in addition to their electrophilic properties, were highly photoreactive molecules able to react with thymine/thymidine to form [2 + 2] photoadducts in very high yields. In all cases a syn regioselectivity was observed, probably associated with the polarization of the exomethylenic bond. This high photoreactivity of α‐methylene‐γ‐butyrolactones towards thymidine could be an explanation of the progressive evolution of allergic contact dermatitis towards chronic actinic dermatitis. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 000–000; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900013
Mirror symmetry breaking of silicon polymers—from weak bosons to artificial helix
Authors: Fujiki Michiya 
Published: November 2009

AbstractFrom elemental particles to human beings, matter and living worlds in our universe are dissymmetric with respect to mirror symmetry. Since the early 19th century, the origin of biomolecular handedness has been puzzling scientists. Nature's elegant bottom‐up preference, however, sheds light on new concepts of generating, amplifying, and switching artificial polymers, supramolecules, liquid crystals, and organic crystals that can exhibit ambidextrous circular dichroism in the UV/Visible region with efficiency in production under milder ambient conditions. In the 1920s, Kipping, who first synthesized polysilanes with phenyl groups, had much interest in the handedness of inorganic and organic substances from 1898 to 1909 in his early research life. Polysilanes—which are soluble Si‐Si bonded chain‐like near‐UV chromophores that carry a rich variety of organic groups—may become a bridge between animate and inanimate polymer systems. The present account focuses on several mirror symmetry breaking phenomena exemplified in polysilanes carrying chiral and/or achiral side groups, which are in isotropic dilute solution, as polymer particles dispersed in solution, and in a double layer film immobilized at the solid surface, and subtle differences in the helix, by dictating ultimately ultraweak chiral forces at subatomic, atomic, and molecular levels. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 000–000; 2009: Published online in Wiley InterScience (www.interscience.wiley.com)DOI 10.1002/tcr.200900018
Atypical presentation of ruptured ectopic pregnancy
Authors: Maharajan Pushpakala Ajaya , Minas Vasileios , Gupta Nandini 
Published: November 2009

AbstractThe authors present a case history of a woman with vaginal bleeding who was found to have a ruptured ectopic pregnancy, initially misdiagnosed as an incomplete miscarriage. Doctors need to have a high suspicion of ectopic pregnancy in early diagnosis and interventions. Copyright © 2009 Wiley Interface Ltd
Transient chaotic behaviour versus periodic motion of a parametric pendulum by recurrence plots
Authors: Litak G. , Wiercigroch M. , Horton B.W. , Xu X. 
Published: November 2009

AbstractWe investigated dynamic responses of a parametric pendulum obtained experimentally. Using the recurrence plot technique designed to analyze experimental time series we have distinguished different types of motion. This method, supplemented by recurrence quantification analysis (RQA), has been used to identify oscillations, rotations, and transient chaotic vibrations for relatively short time series composed of only few cycles.
Effects of finite dimension on the electro‐elastic responses of an interface electrode in a piezoelectric actuator
Authors: Li Y.‐D. , Lee K.Y. 
Published: November 2009

AbstractAll piezoelectric actuators are of finite dimension. The effect of finite geometry on the electro‐elastic responses is of significance to the design of practical actuators. Electromechanical model is established for an interface electrode in a piezoelectric actuator with finite dimension. The methods of infinite series and Cauchy singular integral equation are employed to perform the electro‐elastic analysis. The accuracy of numerical calculation is analyzed and the suitability of the present methods is discussed. Parametric studies on the electro‐elastic intensity factors yield three conclusions. (a) A central electrode rather than an off‐center one can help to enhance the structural reliability. (b) For an actuator with central electrode, it is better to make the interface twice as long as the electrode. For an actuator with periodical interface electrodes, the optimal allocation of electrodes is to make the space identical to the electrode length. (c) The thickness of the piezoelectric layer should be at least a quarter of the electrode length.
A data-flow approach to test multi-agent ASMs
Authors: Cavarra Alessandra 
Published: November 2009

AbstractThis paper illustrates the theoretical basis of an approach to apply data flow testing techniques to abstract state machines (ASMs). In particular, we focus on multi-agent ASMs extended with theseqconstruct for turbo ASMs. We explain why traditional data flow analysis can not simply be applied to ASMs: data flow coverage criteria are strictly based on the mapping between a program and its flow graph whereas in this context we are interested in tracing the flow of data between states in ASM runs as opposed to between nodes in a program’s flow graph. We revise the classical concepts in data flow analysis taking into account the specific, parallel nature of ASMs, and define them on two levels: the syntactic (rule) level, and the computational (run) level. In particular, we analyze the role played by different types of terms in ASMs and deal with the problem of terms that are monitored by a given agent but controlled by another one, terms that are shared between several agents, and derived terms. We also discuss what consequences the use of the turbo ASM constructseqhas on our analysis and revise the approach accordingly. Finally, we specify a family of ad hoc data flow coverage criteria for this class of ASMs and introduce a model checking-based approach to generate automatically test cases satisfying a given set of coverage criteria from ASM models.
HOCl‐Mediated Glycerophosphocholine and Glycerophosphoethanolamine Generation from Plasmalogens in Phospholipid Mixtures
Authors: Leßig Jacqueline , Fuchs Beate 
Published: November 2009

AbstractMany mammalian tissues and cells contain, in addition to (diacyl) phospholipids, considerable amounts of plasmalogens, which may function as important antioxidants. Apart from the “scavenger” function mediated by the high sensitivity of the vinyl‐ether bond, the functional role of plasmalogens is so far widely unknown. Furthermore, there is increasing evidence that plasmalogen degradation products have harmful effects in inflammatory processes. In a previous investigation glycerophosphocholine (GPC) formation was verified as a novel plasmalogen degradation pathway upon oxidation with hypochlorous acid (HOCl), however these investigations were performed in simple model systems. Herein, we examine plasmalogen degradation in a more complex system in order to evaluate if GPC generation is also a major pathway in the presence of other highly unsaturated glycerophospholipids (GPL) representing an additional reaction site of HOCl targets. Using MALDI–TOF mass spectrometry and 31P NMR spectroscopy, we confirmed that the first step of the HOCl‐induced degradation of GPL mixtures containing plasmalogens is the attack of the vinyl‐ether bond resulting in the generation of 1‐lysophosphatidylcholine (lysoPtdCho) or 1‐lysophosphatidylethanolamine. In the second step HOCl reacts with the fatty acyl residue in the sn‐2 position of 1‐lysoPtdCho. This reaction is about three times faster in comparison to comparable diacyl‐GPL. Thus, the generation of GPC and glycerophosphoethanolamine (GPE) from plasmalogens are relevant products formed from HOCl attack on the vinyl‐ether bond of plasmalogens under pathological conditions.
Klinik und Genetik der Neurofibromatose Typ 1
Authors: Kehrer-Sawatzki H. , Mautner V.-F. 
Published: November 2009

ZusammenfassungDie Neurofibromatose Typ 1 (NF1) ist eine autosomal-dominant vererbte Erkrankung. Sie wird durch Mutationen imNF1-Gen auf Chromosom 17q11.2 verursacht. Sie zeigt volle Penetranz, d. h. jeder, der eine Mutation trägt, weist Merkmale der Krankheit auf, jedoch mit z. T. erheblich variabler Expressivität. NF1 ist gekennzeichnet durch die namensgebenden Neurofibrome, bei welchen es sich um gutartige Tumoren der Nervenscheiden handelt. Zu den häufig primär auftretenden Symptomen zählen Pigmentierungsanomalien der Haut, wie Café-au-Lait-Flecken, axilläres bzw. inguinales Freckling, sowie Lisch-Knötchen der Iris. NF1 gehört zur Gruppe der hereditären Tumorerkrankungen. Betroffene weisen ein erhöhtes Risiko auf, an bestimmten NF1-assoziierten Tumoren zu erkranken, die durch eine biallelische Inaktivierung desNF1-Tumorsuppressorgens und aberrante RAS-Signaltransduktion entstehen. In den letzten Jahren sind signifikante Fortschritte bei der Identifizierung und Behandlung der NF1-assoziierten klinischen Symptome sowie in der Entwicklung neuer Therapieansätze zu verzeichnen.