bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling the effects of molecule distortion on the Kondo resonance in the conductance of CoPc/Au(111) and TBrPP‐Co/Cu(111)
Authors: Aguiar‐Hualde J. M. , Chiappe G. , Louis E. , Anda E. V. , Simonin J. 
Published: September 2009

AbstractRecent scanning tunneling microscope (STM) experimental studies on transport through CoPc and TBrPP‐Co molecules adsorbed on metallic surfaces have reported several interesting results: (i) a high Kondo temperature as compared to those of adsorbed undressed magnetic atoms, (ii) the Kondo resonance shows up either as a Kondo peak (CoPc) or as a Fano dip (TBrPP‐Co), (iii) the Kondo temperature depends strongly on the molecule conformation and can be manipulated experimentally. Aiming to propose a theoretical framework that may serve to analyze these observations, we first discuss the case of an isolated magnetic atom adsorbed on a metallic surface. Much of the work on this simple case turns out to be of great help in the analysis of the more complex systems. Then, a simple model is proposed that, capturing the main features of the inner structure of the molecule (four lobe orbitals plus a strongly correlated orbital), offers a physical interpretation for most of the observations on those two moecules. In addition, it allows predicting the behavior of the system upon other symmetry or conformational changes, or when the STM tip is moved away from the Co atom.
Field quenching in photoconductive CdS as possible reason to enhance Voc and FF in thin‐film solar cells
Authors: Böer Karl W. 
Published: September 2009

AbstractField‐quenching via Frenkel–Poole excitation of Coulomb attractive hole traps limits the field in the CdS part of the junctions to 50 kV/cm. This is far below the field in typical other pn‐junctions of thin‐film semiconductors, which exceeds 100 kV/cm and approaches tunneling fields that make junctions leaky, hence reduces both Voc and FF. Field‐quenched CdS may become electronically inverted, thereby providing a possibility that the junction of the CdS/CdTe cell may extend into the CdS, with the cell becoming a hetero structure. With field quenching a region of negative differential conductivity is created causing a high‐field domain that prevents the maximum electric field in the junction to exceed 50 kV/cm, avoiding tunneling, hence electron leakage through it. A preliminary band model of this cell is proposed.
Investigation on upconversion luminescence in Yb3+/Er3+‐codoped Gd2SiO5 single crystal
Authors: Xu Xiaodong , Xu Wenwei , Cheng Yan , Li Dongzhen , Cheng Shishu , Wu Feng , Zhao Zhiwei , Zhou Guoqing , Xu Jun 
Published: September 2009

AbstractYb3+/Er3+‐codoped Gd2SiO5 (Yb,Er:GSO) single crystal was grown by the Czochralski method. The upconversion properties of the crystal under 940 nm excitation were investigated. Intense emission bands centered at 521, 548, and 652 nm corresponding to the transitions 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 of Er3+, respectively, were observed at room temperature. The dependence of the intensity of the Er3+ emission on the pump power and possible upconversion mechanism were discussed and evaluated.
A hard semiconductor OsN4 with high elastic constant c44
Authors: Zhao Wen Jie , Xu Hong Bin , Wang Yuan Xu 
Published: September 2009

AbstractUsing the first‐principles method, we have investigated OsN4 with the orthorhombic Pbca structure. Its elastic constant c44 is larger than all the synthesized 5d transition metal nitrides and borides; besides, OsN4 is found to exhibit large bulk and shear moduli, and small Poisson's ratio. The calculated band structure shows that OsN4 is a semiconductor with a band gap of 0.70 eV. Its insulating behavior mainly comes from the antibonding formed between the nearest N and N and the nearest Os and N atoms. In a word, OsN4 is expected to be a ultra‐hard semiconductor. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray excited optical luminescence from crystalline silicon
Authors: Gundel Paul , Martinez‐Criado Gema , Schubert Martin C. , Sans Juan Angel , Kwapil Wolfram , Warta Wilhelm , Weber Eicke R. 
Published: September 2009

AbstractSynchrotron based X‐ray excited optical luminescence (XEOL) has been measured with many direct bandgap semiconductors. We present XEOL measurements on crystalline silicon (Si), obtained despite of its indirect bandgap and the consequently low luminescence efficiency. Spectra of monocrystalline and multicrystalline (mc) Si at room temperature are compared to theoretical spectra. A possible application in the synchrotron‐based research on mc‐Si is exemplified by combining XEOL, X‐ray fluorescence (XRF) spectroscopy, photoluminescence (PL) spectroscopy, and microscope images of grain boundaries. This approach can be utilized to investigate the recombination activity of metal precipitates, to analyze areas of different lifetimes on mc‐Si samples and to correlate additional material parameters to XRF measurements. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A computational study of the carboxylic acid of phloroglucinol in vacuo and in water solution
Authors: Mammino Liliana , Kabanda Mwadham M. 
Published: September 2009

Abstract2,4,6‐Trihydroxybenzoic acid (FA) is the carboxylic acid of phloroglucinol and, in turn, the parent compound of many biologically active compounds. The biological activities of FA are “extreme” among trihydroxybenzoic acids (e.g., lowest antioxidant activity, highest toxicity toward crustaceans). A complete MP2/6‐31++G(d,p) conformational study in vacuo shows that the lowest energy conformers contain two intramolecular hydrogen bonds between the COOH function and the twoorthophenolic OH, with the Z form of COOH preferred over the E form. Comparisons with conformers in which the H‐bonds are removed enable fairly reliable evaluations of their energy, because of an off‐plane shift of COOH on H‐bond removal, decreasing the effects of lone pair repulsion. Comparisons with the other hydroxybenzoic acids (extensively calculated in vacuo at the same level of theory) suggest that FA has the strongest intramolecular H‐bonds. PCM calculations of FA in water solution show the same sequence of relative stabilities as in vacuo, with narrower differences because of the greater solvent stabilization of higher energy conformers. Calculations of adducts with water molecules H‐bonded to different donor–acceptor centers of FA show the preferred arrangements of water molecules around the different regions of FA and confirm that the stronger intramolecular H‐bonds are not broken on competition with the possibility of formation of intermolecular H‐bonds. HF/6‐31++G(d,p) calculations of adducts, in which the FA molecule is completely surrounded by water molecules, show that 14–16 water molecules (depending on the FA conformer geometry) realize arrangements corresponding to a presumable first solvation layer, with all the water molecules directly H‐bonded to donor–acceptor centers of FA or bridging water molecules directly H‐bonded to them. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Absolute stability of Lurie networked control systems
Authors: Hao Fei , Zhao Xianghui 
Published: September 2009

AbstractThis paper is concerned with the absolute stability problem of networked control systems (NCSs) with the controlled plant being Lurie systems (Lurie NCSs), in which the network‐induced delays are assumed to be time‐varying and bounded. First, in consideration of both the time‐varying network‐induced delays and data packet dropouts, the Lurie NCSs can be modeled as a multiple‐delays Lurie system. Then, a delay‐dependent absolute stability condition is established by using the Lyapunov–Krasovskii method. Next, two approaches to controller design are proposed in the terms of simple algebra criteria, which are easily solved via the toolbox in Matlab. Furthermore, the main results can be extended to robust absolute stability of Lurie NCSs with the structured uncertainties, where robust absolute stability conditions and approaches to robust controller design are presented. Finally, two numerical examples are worked out to illustrate the feasibility and the effectiveness of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.
A frailty model approach for regression analysis of multivariate current status data
Authors: Chen Man‐Hua , Tong Xingwei , Sun Jianguo 
Published: September 2009

AbstractThis paper discusses regression analysis of multivariate current status failure time data (The Statistical Analysis of Interval‐censoring Failure Time Data. Springer: New York, 2006), which occur quite often in, for example, tumorigenicity experiments and epidemiologic investigations of the natural history of a disease. For the problem, several marginal approaches have been proposed that model each failure time of interest individually (Biometrics2000;56:940–943;Statist. Med.2002;21:3715–3726). In this paper, we present a full likelihood approach based on the proportional hazards frailty model. For estimation, an Expectation Maximization (EM) algorithm is developed and simulation studies suggest that the presented approach performs well for practical situations. The approach is applied to a set of bivariate current status data arising from a tumorigenicity experiment. Copyright © 2009 John Wiley & Sons, Ltd.
Sampling of subpopulations in two‐stage surveys
Authors: Clark Robert Graham 
Published: September 2009

AbstractMany health and other surveys aim to produce statistics on small subpopulations, such as specific ethnic groups or the indigenous population of a country. In most countries, there is no reliable sampling frame of the subpopulations of interest, hence it is necessary to sample from the general population, which can be very expensive. A range of issues and strategies for sampling rare subpopulations is reviewed. The most common approaches in practice are the use of a large screening sample, and disproportionate sampling by strata. Optimal sample designs have been derived for the case of one‐stage sampling, but most household interview surveys use two or more stages of selection. This paper develops optimal designs for two‐stage sampling, where there is auxiliary information on subpopulation numbers for each primary sampling unit. Various alternative designs are evaluated using a simulated population derived from the New Zealand Census. Copyright © 2009 John Wiley & Sons, Ltd.
Study on the seismic performance of a multi‐tower connected structure
Authors: Zhou Ying , Lu Xilin , Lu Wensheng , Qian Jiang 
Published: September 2009

AbstractMany reinforced concrete or steel reinforced concrete single‐tower buildings have been built in China. The structural performance of such one‐tower structural systems depends on that of the primary components that are structural walls or moment‐resistant frames. For multi‐tower connected structures, problems become more complex. A multi‐tower connected building, with large floor slab openings in plan and long‐span truss in elevation, was thus studied because of its structural complexity and irregularity. First, a 1/25 scaled model structure was tested on the shake table under minor, moderate, and major earthquake levels. Then, the dynamic responses of the model structure were interpreted to those of the prototype structure according to the similitude laws. The experimental results were also compared with the numerical analysis of a three‐dimensional finite element model for the irregular structure. Both experimental and analytical results demonstrate that, despite of the structural complexity, the overall responses of the building meet the requirements of the Chinese design code and the torsion of the structure is not remarkable. It is suggested that the strength and stiffness of the long‐span connecting truss should be improved due to the potentially large vertical acceleration under strong earthquakes. Copyright © 2009 John Wiley & Sons, Ltd.
Electrochemistry of graphene: new horizons for sensing and energy storage
Authors: Pumera Martin 
Published: September 2009

AbstractGraphene is a new 2D nanomaterial with outstanding material, physical, chemical, and electrochemical properties. In this review, we first discuss the methods of preparing graphene sheets and their chemistry. Following that, the fundamental reasons governing the electrochemistry of graphene are meaningfully described. Graphene is an excellent electrode material with the advantages of conductivity and electrochemistry of sp2 carbon but without the disadvantages related to carbon nanotubes, such as residual metallic impurities. We highlight important applications of graphene and graphene nanoplatelets for sensing, biosensing, and energy storage. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 211–223; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900008
Organophosphine syntheses via activation of the phosphorus‐silicon bond of silylphosphines
Authors: Hayashi Minoru 
Published: September 2009

AbstractThis paper describes the recent advances in the syntheses of organophosphines by forming several types of phosphorus‐carbon bonds via activation of the phosphorus‐silicon bond of silylphosphines. In this account, the activation methods are classified into three types: nucleophile‐induced activations, reactions with Lewis acid‐activated electrophiles, and transition metal catalyzed reactions. Nucleophile‐induced activations of silylphosphines, especially by a fluoride, generated a reactive phosphide equivalent for selective formation of a P‐C bond. Silylphosphines also reacted selectively with Lewis acid‐activated electrophiles. The Lewis acid mediated/catalyzed additions and substitutions, to form sp3‐carbon‐phosphorus bonds including an asymmetric reaction, are described. Several important types of transition metal catalyzed reactions of silylphosphines are also mentioned in this account. Selective formation of a P‐C bond is achieved through these activations to produce a variety of functional organophosphines including optically active ones. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 236–245; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900011
Ultrasound methods to distinguish between malignant and benign adnexal masses in the hands of examiners with different levels of experience
Authors: Van Holsbeke C. , Daemen A. , Yazbek J. , Holland T. K. , Bourne T. , Mesens T. , Lannoo L. , De Moor B. , De Jonge E. , Testa A. C. , Valentin L. , Jurkovic D. , Timmerman D. 
Published: September 2009

AbstractObjectivesTo determine the effect of an ultrasound training course on the performance of pattern recognition when used by less experienced examiners and to compare the performance of pattern recognition, a logistic regression model and a scoring system to estimate the risk of malignancy between examiners with different levels of experience.MethodsUsing ultrasound images of selected adnexal masses, two trainees classified the masses as benign or malignant by using pattern recognition both before and after they had attended a theoretical gynecological ultrasound course. They also classified the masses by using a logistic regression model and a scoring system, but only after they had attended the course. The performance of these three methods when they were used by the trainees was then compared with that when they were used by experts.ResultsOne hundred and sixty‐five adnexal masses were included, of which 42% were malignant (21% invasive tumors and 21% borderline tumors). The area under the receiver–operating characteristics curve of pattern recognition when used by the trainees was similar before and after they had attended the course. Training decreased sensitivity (84% vs. 70% for Trainee 1, P = 0.004; 70% vs. 61% for Trainee 2, P = 0.058) and increased specificity (77% vs. 92% for Trainee 1, P = 0.001; 89% vs. 95% for Trainee 2, P = 0.058). The performance of pattern recognition was poorer in the hands of the trainees than in the hands of the experts. The sensitivities of the logistic regression model were 70% and 54% for the trainees vs. 83% for an expert (P = 0.020 and < 0.001, respectively) and the specificities were 84% and 94% vs. 89% (P = 0.25 and 0.59, respectively). The sensitivities of the scoring system were 59% and 54% for the trai‐nees vs. 75% for the expert (P = 0.002 and < 0.001, respectively), and the specificities were 90% and 93% vs. 85% (P = 0.103 and 0.008, respectively).ConclusionTheoretical ultrasound teaching did not seem to improve the performance of pattern recognition in the hands of trainees. A logistic regression model and a scoring system to classify adnexal masses as benign or malignant perform less well when they were used by inexperienced examiners than when used by an expert. Before using a model or a scoring system, experience and/or proper training are likely to be of paramount importance if diagnostic performance is to be optimized. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Half Antiperovskites: IV. Crystallographic and Electronic Structure Investigations onA2Rh3S2(A= In, Sn, Tl, Pb, Bi)
Authors: Anusca Irina , Schmid Andreas , Peter Philipp , Rothballer Jan , Pielnhofer Florian , Weihrich Richard 
Published: September 2009

AbstractThe crystal and electronic structures of ordered half antiperovskitesA2Rh3S2=ARh3/2S (A= In, Sn, Tl, Pb, Bi) are investigated. From powder and single crystal data superstructures, rhodium site ordering, trends in bonding and coordination are analysed with respect to theAsite atom. Comparisons address isotypic and isoelectronic relations to monoclinic parkerite (Bi2Ni3S2) type superconductors, the trigonal half‐metal ferromagnet Sn2Co3S2, and rhodium‐containing antiperovskites. Local structure and bonding is analysed with respect to the ordered occupation of half of S2A4sites (= perovskite oxygen sites) and interlinking to 2D networks [Rh3S2]∞δ–by face‐, edge‐ and corner‐sharing. The theoretical part includes DFT band structure and ELF calculations, systematic comparisons to rhodium and antiperovskites, as well as spin‐polarised calculations on Sn2Rh3S2and Pb2Rh3S2.
Syntheses and Characterization of Two Coordination Polymers Constructed by the Ligand 3,5‐Bis(pyridin‐4‐ylmethoxy)benzoic Acid
Authors: Xu Guang‐Juan , Zhao Ya‐Hui , Shao Kui‐Zhan , Xu Yan‐Hong , Wang Xin‐Long , Su Zhong‐Min , Yan Li‐Kai 
Published: September 2009

AbstractTwo coordination polymers, namely [Zn(L1)(OAc)]·H2O (1) and [Cd(L1)2] (2), where L1 = 3,5‐bis(pyridin‐4‐ylmethoxy)benzoic acid, have been synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction analysis. Complex 1 has a 2D layer structure in which the hydrogen bonds between lattice water molecules and uncoordinated carboxylate oxygen atoms of the ligand L1 in the adjacent layers extend the 2D layer into a 3D supramolecular architecture. The structure of 2 is a 2D (3,5)‐connected net with (3·52)(32·53·64·7) topology. In addition, the luminescent properties of complexes 1 and 2 have been studied in the solid state at room temperature.
Ternary Hydroxides II. Synthesis and Crystal Structure of the Layered Barium Hexahydroxidostannate(IV) Pentahydrate, Ba[Sn(OH)6]·5H2O
Authors: Kamaha Shouassi , Reuter Hans 
Published: September 2009

AbstractSingle crystals of Ba[Sn(OH)6]·5H2O (1) were grown by three different methods and the crystal structure was determined by X‐ray diffraction (monoclinic, P21/c, a = 10.3119(2) Å, b = 8.6079(2) Å, c = 23.4906(4) Å, β = 90.774(1)°, V = 2084.93(7) Å3, Z = 8). The fundamental primary building units (PBU′s) consist of two octahedral [Sn(OH)6]2– ions and two monocapped square antiprisms of {Ba(OH)4(H2O)5}. The latter and one of the two {Sn(OH)6} octahedra are linked together through common edges resulting in the formation of layers, the secondary building units (SBU′s). These layers can be described in terms of two {BaO9} Zweier single chains parallel to the b axis which are linked together every second antiprism through common edges with one of its two adjacent chains. The holes between these chains are filled from the {Sn(OH)6} octahedra. In contrast, the second {Sn(OH)6} octahedron has the function of a spacer separating the SBU′s from each other. Furthermore, the interlayer space is filled by five additional water molecules which are not part of any coordination sphere. All building units are held together by an extended network of hydrogen bonds with structural data that indicate medium strong to weak interactions.
Introduction of Copper Ions in the Hexagonal Channels of the Apatite Type La–Sr and La–Ca Silicates
Authors: Kazin Pavel E. , Zykin Mikhail A. , Gazizova Olga R. , Tretyakov Yury D. 
Published: September 2009

AbstractCopper‐containing and copper‐free La–M (M = Sr, Ca) silicates with an apatite‐type structure were prepared by solid state reaction at 1400 °C in air. Samples were studied by powder X‐ray diffraction, electron microscopy with EDX analysis, and magnetic measurements. The crystal structures of the samples were refined by the Rietveld method. Copper was incorporated into the hexagonal channels forming linear O–Cu–O groups with the site occupancies up to 0.37 for M = Sr and 0.31 for M = Ca. The impact of the introduced copper was a substantial increase of the hexagonal channel diameter and a somewhat smaller increase of the lattice parameters. Copper‐containing samples were diamagnetic and not brightly colored in contrast to copper‐doped phosphate apatites.
Surface Effects in the Pressure‐Induced Structural Transformation of a ZnO Nanorod
Authors: Frenzel Johannes , Seifert Gotthard , Zahn Dirk 
Published: September 2009

AbstractWe report on molecular dynamics simulations of an atomistic zinc oxide nanorod model embedded in a pressure medium. The transformation of the nanorod from wurtzite to rocksalt structure is investigated using both “brute‐force” over‐pressurization and transition path sampling at a much lower pressure. The latter approach yields the underlying mechanisms at more realistic conditions and reveals the interplay of the morphogenesis of the rocksalt‐type structure domains with shape deformation of the overall nanorod. Surface effects are observed to not only influence dedicated nucleation sites but also impose control mechanisms to phase growth and to specific shape deformation.
Syntheses, Characterization, and Electrochemical Anion Recognition Investigation of New N‐5‐Ferrocenylisophthalic Amino Acid Methyl Esters
Authors: Liu Wei , Zheng Haijin , Du Lingzhi , Chen Bingyi , Song Maoping 
Published: September 2009

AbstractThe N‐5‐ferrocenylisophthalic amino acid methyl esters derivatives 4a–f were prepared by direct condensation of 5‐ferrocenylisophthalic dichloride to the corresponding amino acid methyl esters. The compounds were fully characterized by a range of NMR spectroscopic techniques, mass spectrometry (ESI‐MS) and cyclovoltammetry (CV). The cyclovoltammetric behavior of 4a–f showed one pair of well‐defined and stable redox waves in potential range of 0.0–0.9 V at the GC electrode, which were attributed to the Fc/Fc+ redox process. Electrochemical investigations of 4a–f demonstrated that addition of H2PO4– resulted in large shifts of the respective Fc/Fc+ couple to more negative potentials (ca. 39–68 mV), which suggests that compounds 4a–f have good abilities in recognizing H2PO4–. Moreover, 1H NMR spectroscopic anion titration studies of 4c and 4e strongly suggest the contributions of the amide and Ar–H protons as the important hydrogen donors in anion binding.