bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monte Carlo simulation of circular grain growth
Authors: Morón Carlos , Maganto Fernando José , Tremps Enrique , Ramírez Puerto , García Alfonso 
Published: March 2011

AbstractMonte Carlo simulations have been carried out to study the effect of temperature on the growth kinetics of a circular grain. This work demonstrates the importance of roughening fluctuations on the growth dynamics. Since the effect of thermal fluctuations is stronger in d =2 than in d =3, as predicted by d =3 theories of domain kinetics, the circular domain shrinks linearly with time as A (t)=A(0)‐αt, where A (0) and A(t) are the initial and instantaneous areas, respectively. However, in contrast to d =3, the slope α is strongly temperature dependent for T≥0.6TC. An analytical theory which considers the thermal fluctuations agrees with the T dependence of the Monte Carlo data in this regime, and this model show that these fluctuations are responsible for the strong temperature dependence of the growth rate for d =2. Our results are particularly relevant to the problem of domain growth in surface science. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Organic glasses: cluster structure of the random energy landscape and its effect on charge transport and injection
Authors: Novikov Sergey V. 
Published: March 2011

AbstractAn appropriate model for the random energy landscape in organic glasses is a spatially correlated Gaussian field, generated by randomly located and oriented dipoles and quadrupoles. Correlation properties of energetic disorder directly dictates the mobility dependence on the applied electric field. Electrostatic disorder is significantly modified in the vicinity of the electrode that affects injection properties. Correlated Gaussian field forms clusters. We suggest a simple method to estimate an asymptotics of the cluster distribution on size for deep clusters where a value of the field on each site is much greater than the rms disorder. Hopping transport in organic glasses in the case of high carrier density could be described in terms of the effective density‐dependent temperature. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Is the marginality of non‐reversible heat flow in MDSC experiments a sufficient criterion for self‐organization in network glass‐formers?
Authors: Shpotyuk O. , Kozdras A. , Golovchak R. , Iovu M. 
Published: March 2011

AbstractPhysical ageing caused by 25‐years natural storage is studied in glassy As25S75 by conventional DSC technique. The observed effect was recorded as a significant increase in the value of glass transition temperature and endothermic peak area in the vicinity of glass‐to‐supercooled liquid transition. This result testifies, that marginal values of non‐reversible heat flow in temperature‐modulated DSC (ΔHnr), observed for as‐prepared (or short‐term aged) AsxS100‐x samples within 22.5 < x < 29.5 compositional range [Ping Chen et al 2008 Phys. Rev. B78 224208], can significantly increase after longer period of physical ageing. Owing to these and previous results on collapse of the reversibility window in AsxSe100‐x glasses after long‐term physical ageing, we have concluded that marginality of non‐reversible heat flow is not a sufficient criterion for express identification of the optimally‐constrained self‐organized phases in chalcogenide glasses. To make a conclusion on the marginality of ΔHnr, the long‐term component of physical ageing should be taken into account. A comparison between conventional or temperature‐modulated DSC scans recorded for long‐term aged and rejuvenated glass samples is considered as a suitable criterion for physical ageing in glasses and, therefore, for the possibility of their network to be optimally‐constrained. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of titanium ions on spectroscopic properties of TeO2‐Sb2O3‐B2O3: TiO2 glass ceramics
Authors: Satyanarayana T. , Gandhi Y. , Valente M. A. , Kityk I. V. , Veeraiah N. 
Published: March 2011

AbstractA family of antimony tellurite glasses of the composition (55‐x)TeO2‐10Sb2O3‐35B2O3 mixed with different concentrations of TiO2 (0 to 2 mol%) were prepared and crystalized. The samples were characterized by XRD and SEM techniques; spectroscopic (optical absorption and Raman) and PIB properties have been investigated. Randomly distributed crystals were identified by SEM. The XRD studies have revealed the presence of Sb2Te2O7, Sb2Te2O9, TiTe3O8,TiBO3 crystalline phases in these samples. The diffraction data also indicated that, the antimony ions coexist in Sb5+ state with Sb3+ state in these samples; however, the concentration of Sb3+ ions seems to be dominant over Sb5+ ions in the samples containing lower concentrations of TiO2. Optical absorption spectral studies have indicated that a considerable proportion of Ti ions do exist in Ti3+ state in addition to Ti4+ state and the redox ratio seems to be increasing with increase in the concentration of TiO2. The Raman spectral studies have revealed the presence of several conventional structural groups viz., TeO4, SbO3, BO3, BO4, TiO4,TiO6 in the glass ceramic network; these studies have also indicated a growing degree of disorder in the glass ceramic with increase in the concentration of TiO2. The experiments on PIB with 7 ns 1064 nm Nd:YAG laser beam indicated the maximum intensity of birefringence for the sample crystallized with 2.0 mol% of TiO2. This result combined with the optical absorption studies allowed us to conclusion that Ti ion surrounding ligands play principal role in the observed PIB effects (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Glass formation in the V2O5‐MoO3‐ZnO system
Authors: Markova‐Velichkova Maya , Iordanova Reni , Dimitriev Yanko 
Published: March 2011

AbstractGlass formation region in the V2O5‐MoO3‐ZnO system was determined using low cooling rates (102 K/s). The glasses were obtained in the central part of the system from compositions containing 10‐65 mol% V2O5, 10‐65 mol% MoO3 and 10‐50 mol% ZnO. The amorphous and crystalline phases were characterized by x‐ray diffraction (XRD), differential thermal analysis (DTA) and infra‐red spectroscopy (IR). According to DTA data the glass compositions with molar ratio of the components near to 1:1:1 are more stable against crystallization. Structural models for V2O5‐MoO3‐ZnO glasses were suggested on the basis of IR spectral investigation, and by comparing with the data of known crystalline structures. It was established that VO5 groups associated in layers or chains, isolated V2O7 pyrovanadate units and MoO6 groups are the main structural units creating amorphous networks. ZnO depolymerizes vanadate and molybdate amorphous networks (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dielectric and electrical properties investigation of polyamide/polyaniline composite films
Authors: Mezdour Dounia zed , Tabellout Mohamed , Bouanga Christele Vanga , Sahli Salah 
Published: March 2011

AbstractSurface conductive composites for antistatic purposes consisting of polyamide 6 (PA‐6) polymer films as a matrix containing conductive polyaniline (PANI) particles were chemically elaborated at room temperature by in situ polymerization of aniline inside the matrix. These kind of Polyamide/PANI composites were investigated regarding to their microstuctural and electrical properties. The surface conductivity was characterized using the potential decay technique. The results were correlated with scanning electron microscopic images data concerning PANI particles dispersion in these antistatic polymer films (ASPF). The enhanced surface conductivity was due to percolation of the PANI phase in the surface layer of PA‐6 films. It has been shown by X ray spectra that the crystallinity of the films is also enhanced. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical, dielectric and structural properties of borovanadate glass systems doped with samarium oxide
Authors: Graça M. P. F. , Fawzy H. , Badr Y. , Elokr M. M. , Nico C. , Soares R. , Costa L. C. , Valente M. A. 
Published: March 2011

AbstractGlasses doped with rare earth (RE) ions are widely studied due to the numerous applications of these systems (active media for solid state lasers, optical telecommunication, non‐linear optical materials, electro‐optic devices, etc.). Boron trioxide, B2O3, is a known glass forming oxide with a relative low melting temperature. The addition of a transition metal oxide, such as V2O5, promotes the exhibition of semiconducting properties making these promising systems for several technological applications, such that ones involved in solar energy conversion devices. It is known that alkali borovanadate glasses, like alkali borate glasses themselves, are ionically conducting materials. Despite their importance there are only few studies on these glasses reported on literature. Thus, the alkali‐borovanadate glass system constitutes a family with high interest from the electrical and dielectric point of view. The effect of the increment of alkali quantity in the electrical and dielectric response of these glasses and the physical/structural explanation are questions which will be addressed. In this work, the transparent glass samples with molar composition 0.01Sm2O3‐0.99[0.85B2O3‐(0.15‐x)Li2O‐xV2O5] with x = 0, 0.1, 0.2, 0.35, 0.5 and 2 (mol%) were prepared by conventional melting technique. The prepared samples were fully characterized using different experimental techniques such as, differential thermal analysis (DTA), X‐ray diffraction (XRD), electrical and dielectric measurements. The samples structure, electrical and dielectric properties as a function of vanadium ions content was explored and discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The crystallization kinetics of Sb2S3 in (GeS2)0.4(Sb2S3)0.6 glass
Authors: Zmrhalová Zuzana , Málek Jiří , Švadlák Daniel , Barták Jaroslav 
Published: March 2011

AbstractThe crystallization kinetics of antimony trisulphide in (GeS2)0.4(Sb2S3)0.6 glass has been studied by thermomechanical analyzer and microscopy. The linear crystal growth kinetics of Sb2S3 has been observed in the temperature range 293 °C ≤ T ≤ 327.5 °C. The activation energy determined of TMA method (E = 240 ± 5 kJ·mol‐1) is relatively close to the activation energy of crystal growth (EG = 274 ± 7 kJ·mol‐1) from optical microscopy measurements. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of the simulation area on the liquid‐solid phase diagram in molecular dynamics
Authors: Rutkevych P. P. , Wu D. T. 
Published: March 2011

AbstractIn this work we analyze the effects of the fixed size of the simulation box on the properties of liquid‐solid interface in NVT ensemble (constant number of particles, volume, and temperature). Due to spatial constraints implied by the fixed shape of the box the equilibrium parameters like density and pressure of the system depend on the temperature and the region size. Our simulations for a fixed number of crystal planes show that the lattice parameters of the crystal are continuous functions of the simulation box size in the vicinity of the equilibrium box size under the condition of isotropic stress.While the lattice parameters can be used to determine the box with isotropic stress, doing so requires repetitive simulations and root finding. To resolve the constraints problem, we propose a tilted crystal configuration, that can be used for calculation of bulk properties and is less sensitive to size limitations in NVT ensemble. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local geometric algorithm for hole boundary detection in sensor networks
Authors: Shirsat Amit , Bhargava Bharat 
Published: March 2011

AbstractWe present a hole boundary detection algorithm for sensor network which identifies the geographical boundary of voids in the network assuming the relative geographic information of only 2‐hop neighbors. We formalize the fuzzy notion of a hole by relating it to the graph theoretic concept of a chordless cycle enclosing a face in an arrangement of lines. Furthermore, the algorithm for detecting such topological holes is distributed, O(k) per node computation (for k 2‐hop neighbors) and requires synchronization between nodes that are no more than 2‐hops away. The algorithm takes a local best‐effort approach and does not verify if the nodes indeed form a closed polygonal loop. We believe that this local effort is sufficient based on theoretical observations and experiments. In the simulation tests we conducted, this was hardly a restriction in correctly identifying the simple, closed polygonal loops. We discuss the security implications of the hole detection framework in the context of sensor networks. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of theoretical contribution, methodological rigor, and journal quality, on the impact of scale development articles in the field of entrepreneurship
Authors: Kuskova Valentina V. , Podsakoff Nathan P. , Podsakoff Philip M. 
Published: March 2011

AbstractDespite the widespread belief that empirical studies that are firmly grounded in theory and use valid measures of their focal constructs are more critical to the advancement of science than studies that do not possess these attributes, it is only recently that this belief has begun to be empirically tested. Unfortunately, most of the tests that have been conducted have some limitations. Therefore, the purpose of this study is to examine the effects that an article's theoretical contribution, the rigor of its scale validation procedures, and the quality of the journal in which it is published have on its impact in the field of entrepreneurship. Using expectancy theory as a conceptual framework, we develop and test our hypotheses in a sample of 88 entrepreneurship articles that reported scale development and validation evidence. Our hypotheses were supported in that the results showed that an article's theoretical contribution, methodological rigor, and journal quality significantly predicted the number of citations the article received, even after controlling for article age‐ and author‐related variables. When taken together, the article characteristics and control variables accounted for 66 percent of the variance in article citations. Implications of these findings for researchers in the field of entrepreneurship are discussed. Copyright © 2011 Strategic Management Society.
Effects of initial teamwork capability and initial relational capability on the development of new technology‐based firms
Authors: Brinckmann Jan , Hoegl Martin 
Published: March 2011

AbstractNew technology‐based firms face substantial resource constraints. This study examines how teamwork capability and relational capability of the entrepreneurial team affects the development of new firms. Teamwork capabilities are captured by the quality of collaboration of the entrepreneurial team members among themselves. Relational capabilities are analyzed based on the collaboration of the entrepreneurial team members with partners external to the focal firm. Our findings show that teamwork and relational capabilities, while theoretically originating from social capabilities, can have diverging effects on the development of a new organization. We find that relational capabilities lead to founding team member additions as well as sales and employment growth. In contrast, teamwork capabilities lead to a reduced likelihood to add founding team members and do not affect sales and employment growth. Theoretical and practical implications are discussed. Copyright © 2011 Strategic Management Society.
Complementary effects of network range and tie strength in enhancing transnational venture performance
Authors: Patel Pankaj C. , Terjesen Siri 
Published: March 2011

AbstractWe examine the complementary effects of network range and tie strength on the performance of ventures in the context of the transnational entrepreneur (TE). Network range facilitates access to a broad set of knowledge and resources; however these resources may be activated only in the presence of strong ties. Alternatively, a network heavy in strong ties provides reliable connections, but a lack of range can lead to network closure. Using a sample of 452 TE ventures, we find that tie strength enhances venture performance, but network range does not have a significant effect. Furthermore, taken together, tie strength and network range significantly enhance TE venture performance. Supermodularity and linear restriction tests indicate asymmetric complementarity between network range and tie strength. Tie strength is a critical input and network range plays a supporting role in a TE's venture performance. Copyright © 2011 Strategic Management Society.
The mediating role of knowledge‐based capital for corporate entrepreneurship effects on performance: A study of small‐ to medium‐sized firms
Authors: Simsek Zeki , Heavey Ciaran 
Published: March 2011

AbstractEven though research suggests that a firm's pursuit of corporate entrepreneurship directly contributes to its performance, we develop a deeper explanation, based on the insight that this pursuit develops and extends the firm's knowledge‐based capital. Specifically, we first demonstrate that the pursuit of corporate entrepreneurship enhances the firm's knowledge‐based capital residing in people (human capital), relationships (social capital), and systems (organizational capital). Then, we examine the mediating role of each capital type for corporate entrepreneurship effects on performance. We test our hypotheses using multisource data from a sample of CEOs and their top management teams in 125 firms, including a time‐lagged measurement of knowledge‐based capital and performance. Our findings provide general support for this theory and indicate that corporate entrepreneurship is positively associated with knowledge‐based capital and through this, with performance. Copyright © 2011 Strategic Management Society.
Direct Control of the Spatial Arrangement of Gold Nanoparticles in Organic–Inorganic Hybrid Superstructures
Authors: Hermes Jens P. , Sander Fabian , Peterle Torsten , Cioffi Carla , Ringler Philippe , Pfohl Thomas , Mayor Marcel 
Published: March 2011

AbstractThe directed assembly of gold nanoparticles is essential for their use in many kinds of applications, such as electronic devices, biological labels, and sensors. Herein an atomic alteration in the molecular structure of ligand‐stabilized gold nanoparticles that can shift the interparticle distance up to 1 nm upon covalent coupling to organic–inorganic superstructures is presented. Gold nanoparticles are stabilized by two octadentate thioether ligands and have a mean diameter of 1.1 nm. The ligands contain a central rigid rod varying in length and terminally functionalized with a protected acetylene. The two peripheral functional groups on each particle enable the directed assembly of nanoparticles to dimers, trimers, and tetramers by oxidative acetylene coupling. This is a wet chemical protocol resulting in covalently bound nanoparticles. These organic–inorganic hybrid superstructures are analyzed by transmission electron microscopy, small angle X‐ray scattering, and UV/vis spectroscopy. The focus of the comparison here is the subunit, which is anchoring the bridgehead, either a pyridine or benzene moiety. The pyridine‐based ligands reflect the calculated length of the rigid‐rod spacer in their interparticle distances in the obtained hybrid structures. This suggests a perpendicular arrangement that results from the coordination of the pyridine’s lone pair to the gold surface. An atomic variation in the ligand’s center leads to smaller interparticle distances in the case of hybrid structures obtained from benzene ligands. This large difference in the spatial arrangement suggests a tangential arrangement of the interparticle bridging structure in the latter case. Consequently a rather flat arrangement parallel to the particle surface must be assumed for the central benzene unit of the benzene‐based ligand.
Influence of Relative Humidity on the Nanoscopic Topography and Dielectric Constant of Thin Films of PPy:PSS
Authors: Sun Ling , Wang Jianjun , Butt Hans‐Jürgen , Bonaccurso Elmar 
Published: March 2011

AbstractThe morphological, electric, and dielectric properties of water‐based conjugated polymer blends, such as polypyrrole:polystyrene sulfonate (PPy:PSS) or poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), are known to be influenced by the water content. These properties also influence the macroscopic performance when the conjugated polymer blends are employed in a device. An in situ humidity‐dependence study on thin films of PPy:PSS by Kelvin probe force microscopy (KPFM) is presented. A particular KPFM mode, dielectric imaging, is used, which detects the second harmonic electrostatic force. Thin PPy:PSS films are drop‐coated on hydrophobic graphite substrates. Upon increasing the relative humidity, the hydrophilic PSS is swelled and dewetted on the substrate, while the hydrophobic PPy remains almost unchanged. The swelling and dewetting of PSS results in irreversible morphological changes in the thin films, as well as nanoscopic rearrangement on the surface of the PPy:PSS films. The nanoscopic rearrangement can only be detected by dielectric imaging. It is also observed that relative humidity affects unannealed and thermally annealed PPy:PSS thin films differently.
Toward rational design of complex nanostructured liquid crystals
Authors: Yoneya Makoto 
Published: March 2011

AbstractAn analogy of block copolymer micro‐segregation as a low‐molecular weight nanostructured liquid crystal (LC) was tested with recently found columnar and cubic phase‐forming LC molecules, to clarify the broader applicability of the analogy as a molecular design principle. We found that the copolymer analogy principle also works well for new micellar cubic phase‐forming molecules. For bicontinuous cubic phase‐forming 1,2‐bis(4′‐n‐alkoxybenzoyl)hydrazines (BABH‐n) compounds that cover a much broader core fraction range than that predicted by the copolymer analogy, we propose hierarchical preferential orientation as an additional mechanism for their cubic range broadening. For azo‐dichiral molecules that also do not fit with the above principle, we propose chiral segregation as an alternative origin for their cubic phase formation. DOI 10.1002/tcr.201000025