bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroscopy of Eu:YAG nanopowders
Authors: Georgescu S. , Chinie A. M. , Stefan A. , Toma O. 
Published: March 2007

AbstractYAG:Eu nanopowders were synthesized by a nitrate‐citrate sol‐gel method. The morphologic modifications produced by thermal treatments at various temperatures were monitored by a series of parameters obtained from the optical fluorescence spectroscopy: intensity ratio of the transitions 5D0 → 7F2 and 5D0 → 7F1, the maximum splitting of the 7F1 level, and the linewidths of some fluorescence transitions. Abrupt changes of the monitored parameters are observed at the amorphous‐crystalline transition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ionic mechanisms in the optically stimulated luminescence of quartz
Authors: Martini M. , Galli A. 
Published: March 2007

AbstractAmong the many centres found in crystalline quartz it is well known that Al, substitutional for Si, is always present in different concentrations giving rise at Room Temperature to ionic migration of the associated alkali ions. Many authors evidenced that these alkali ions are involved in trapping and recombination at the basis of Thermally and Optically Stimulated Luminescence, TL and OSL respectively. We have focused our attention on the OSL of quartz that is now widely used in sediment dating, although the trapping‐detrapping mechanisms have not yet been clarified. Bulk synthetic crystalline quartz, with known concentrations of Al and alkali ions has been used. There is evidence that an ionic migration is at the basis of the OSL phenomenon, linking OSL emission with the TL peaks known as “110 °C” and “325 °C”. This result is also supported by Radioluminescence (RL) measurements performed on swept and unswept quartzes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermoluminescence and visible reflectance spectroscopy applied to the study of blue‐green mosaic silica‐glass tesserae
Authors: Galli A. , Poldi G. , Martini M. , Sibilia E. 
Published: March 2007

AbstractWe report the results of a series of measurements of Thermally Stimulated Luminescence (TSL) and visible reflectance spectrometry (vis‐RS) performed on several modern blue‐green silica glass mosaic tesserae. They were produced from the same matrix with different additions of colouring and opacifying oxides to get a wide shadow of blue colorations. This study follows others previously performed on archaeological mosaics, and aims at the understanding of the TSL emission of this class of glasses, particularly suitable for dating. The usefulness of the combined techniques for the identification of the metal ions responsible for the blue coloration in a given sample is confirmed as well as the positive role played by antimony in enhancing the TSL response. In general, however, the TSL characteristics of mosaic glasses depend on the glassy matrix and on its crystallisation degree rather than on the formation of colour centres associated to the introduction of colouring oxides. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and macro defects of ZnO single crystals
Authors: Li Xinhua , Xu Jiayue , Shen Hui , Wu Anhua , Li Xiaomin 
Published: March 2007

AbstractZnO single crystal has been grown from 22 mol%ZnO‐78 mol%PbF2 high temperature solution in a homemade vertical Bridgman furnace. The macro growth defects, such as growth striations, boundary, negative crystal, bubbles, and inclusions, were investigated by optical microscopy and an electron probe X‐ray microanalyser (EPMA). The formation mechanisms of these defects were discussed associated with the growth parameters. The approaches to reduce macro defects were proposed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion size effect dependence on the glow peak temperature in europium doped mixed crystals
Authors: Rodríguez‐Mijangos R. , Pérez‐Salas R. 
Published: March 2007

AbstractThe ion size effect on the thermoluminescence (TL) glow curve structure of europium doped binary mixed alkali halide crystals samples was investigated as a function of molar composition. A linear expression, that relates the characteristic glow peak temperature to the ionic size, was found and used to predict the TL temperature shifts associated to the size of Cl– and Br– anions in a binary mixed alkali halide sample at a given composition. In addition the behavior of the mixed binary crystals with components KCl and RbCl doped with divalent Europium is presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence in AlN: macro‐size and nano‐powder
Authors: Berzina B. , Trinkler L. , Grabis J. , Steins I. 
Published: March 2007

AbstractPhotoluminescence (PL) properties in AlN are studied when size of polycrystalline grains is reduced from macro‐size (AlN ceramics and macro‐size powder) to nano‐size (nano‐powder). It was found that in all these materials within the UV‐ blue spectral region two PL bands are observed at ∼400 nm (caused by the oxygen‐related defects) and at 480 nm (with unknown defect structure) but the ratio of their intensities depends on the grain size. Reduction of AlN grain size results in decrease of the 400 nm band and increase of the 480 nm band. It allows the following conclusions: i) reduction of AlN grain size results in decrease of oxygen (the native impurity of AlN) content in the crystalline lattice, and ii) the defects responsible for 480 nm PL band could originate from the material surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intrinsic luminescence of YAlO3 perovskites
Authors: Zorenko Yu. , Voloshinovskii A. , Gorbenko V. , Zorenko T. , Nikl M. , Nejezchleb K. 
Published: March 2007

AbstractIntrinsic emission of complex oxides with perovskite structure was analyzed in the undoped single crystal (SC) and single crystalline films (SCF) of YAlO3 (YAP) using the time‐resolved luminescence spectroscopy under excitation by synchrotron radiation. In contrast to bulk SC the YAP SCF are characterized by much lower concentration of YAl antisite and vacancy‐type defects, which contribute to the intrinsic emission of YAP SC. Such a difference comes mainly from much lower temperature of the film growth using the Liquid Phase Epitaxy. For this reason, comparison of YAP SC and SCF appears very useful to study the nature of the intrinsic emission of perovskites consisting mainly of the exciton and defect‐related luminescence. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy dependence of the electron‐hole in‐plane anisotropy in InAs/GaAs quantum dots
Authors: Testelin C. , Aubry E. , Chaouache M. , Maaref M. , Bernardot F. , Chamarro M. , Gérard J.‐M. , Ferreira R. 
Published: March 2007

AbstractDue to a regrettable technical error some Greek and special letters in the paper were not reproduced. Please, find here the fully corrected article.In pump‐probe experiments, we measured the anisotropic exchange energy splitting of the low‐lying electron‐hole pair states in an ensemble of as‐grown InAs/GaAs self‐assembled quantum dots. This splitting shows a monotonic decrease with the energy of interband emission. We discuss this result considering different parameters: shape anisotropy, wavefunction confinement, size of the quantum dots, and piezoelectric effect. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical investigations on analytical potential energy function and spectroscopic parameters for the state b3Πu of dimer 7Li2
Authors: Shi De‐Heng , Sun Jin‐Feng , Zhu Zun‐Lue , Ma Heng , Liu Yu‐Fang , Zhu Zheng‐He 
Published: March 2007

AbstractThe SAC‐CI (symmetry‐adapted‐cluster configuration‐interaction) method presented in Gaussian 03 program package is applied to investigate the adiabatic potential energy curves (PECs) of 7Li2(b3Πu). These calculations are performed at numbers of basis sets, such as 6‐311++G(3df,3pd), 6‐311++G(2df,2pd), 6‐311++G(df,pd), D95V++, D95(3df,3pd), D95(d,p), cc‐PVTZ, 6‐311++G and 6‐311++G(d,p). All the ab initio calculated points are fitted to the analytic Murrell‐Sorbie functions and then used to compute the spectroscopic parameters. The analytic potential energy function (APEF) for this b3Πu state is reported. By comparison, the spectroscopic parameters reproduced by the APEF attained at 6‐311++G(2df,2pd) are found to be very close to the latest experimental findings. With the APEF obtained at the SAC‐CI/6‐311++G(2df,2pd) level of theory, a total of 62 vibrational states is found when J = 0. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants for these vibrational states are also reported. The reasonable dissociation limit for this state is deduced using the calculated results at present. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Planar mono‐, di‐ aza‐ and phospha‐naphthalene: Structure and aromaticity
Authors: Wang Lei , Wang Haijun 
Published: March 2007

AbstractIn this article, we used magnetic criteria, magnetic susceptibility isotropic and nucleus‐independent chemical shifts (NICS), calculated with (density functional theory) B3LYP levels at the 6‐31G** basis set, to evaluate aromaticity of a set of 29 planar bicyclic π‐electron systems: naphthalene and its mono‐ and di‐ aza‐ and phospha‐derivatives. The result showed significant collinearity of the above two magnetic criteria when evaluating N‐containing naphthalenes, but did not speak with the same voice when evaluating P‐containing naphthalenes. Thus, we could conclude that magnetic susceptibility is a reliable criterion and NICS is not in our case. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Theoretical study on AlnO2 (n = 1–10) clusters and O2 adsorption on the Al(111) surface
Authors: Sun Jiao , Lu Wen‐Cai , Wang Hong , Zhao Li‐Zhen , Sheng Li Ze‐ , Sun Chia‐Chung 
Published: March 2007

AbstractThe structural properties of neutral and ionic AlnO2 (n = 1–10) clusters have been systematically investigated using the density functional method B3LYP with a standard 6‐311+G(d) basis set. The calculated results show that in the AlnO, AlnO2, and AlnO (n ≥ 3) clusters, O atoms tend to penetrate into the aluminum clusters with some Al atoms moving outward. The binding energies and natural charges populations indicate that the oxygen‐etching is generally stronger in the order Al < Aln < Al for n < 3, and Al > Aln > Al for n ≥ 3. To further understand the mechanism of interaction between Al and O2, the adsorption of O2 on the Al(111) surface was studied using the density functional theory with plane wave pseudopotential method. The calculated results are consistent with the experimental observation that the O2 molecule would dissociate on the Al(111) surface and be adsorbed in adjacent hollow sites, forming a local structure of Al3O–Al3O. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Preparation of a biochip on porous silicon and application for label‐free detection of small molecule‐protein interactions
Authors: Hu Ligang , Xu Songyun , Pan Chensong , Zou Hanfa , Jiang Guibin 
Published: March 2007

AbstractA new approach for the preparation of a biochip on porous silicon and the application of the biochip for detection of small molecule‐protein interactions with desorption/ionization on porous silicon (DIOS) was demonstrated. The galvanostatically etched porous silicon substrates were chemically modified firstly to yield carboxylic acid terminated surfaces, and then the protein was covalently attached to the surface through amide bonding. By applying a solution of candidate chemicals to the surface and a subsequent wash step, the masses of captured compounds could be analyzed by DIOS. DIOS has advantages of being a direct detection tool compared to the classic florescence or chemiluminescence methods, because the process of labeling molecules employed in the florescence or chemiluminescence methods can sometimes alert the properties of the labeled molecule. The recognition between proteins and their binding partners is efficient and selective. A good tolerance to disturbance and high enrichment factor of the biochip to the analytes was observed. As an on‐chip‐based approach, the demonstrated method has a potential to perform in a high‐throughput format. Copyright © 2007 John Wiley & Sons, Ltd.
Distinction of gaseous soot precursor molecules and soot precursor particles through photoionization mass spectrometry
Authors: Happold Joachim , Grotheer Horst‐Henning , Aigner Manfred 
Published: March 2007

AbstractSamples were drawn from sooting premixed low‐pressure ethylene oxygen flames and investigated through photoionization mass spectrometry using either KrF or ArF lasers as the radiation source. With the former, mass spectra were obtained as described in the literature and characterized through a series of signal groups, one for each C‐number and extending to aboutm/z1000, assigned as a PAH series. When the ArF laser was used the same series was observed with a somewhat higher sensitivity. In addition, a new series was observed overlaid on the PAH series and starting at aboutm/z680. The new series exhibited abundant ions and it completely dominated the spectrum beyondm/z1000. This series was identified as being the spectrum of soot precursor particles. Through measurement of the ionization order it was concluded that at least two photons are needed for ionization of PAHs whereas the particles need only one photon. Consequently, they can be measured with high sensitivity when an ArF laser is used as the radiation source. Furthermore, the discrimination of soot precursor molecules and soot precursor particles becomes possible through photoionization and this enables an improved understanding of the mass spectra. This should allow a particle growth mechanism to be deduced in the near future. Copyright © 2007 John Wiley & Sons, Ltd.
XPS characterization of the corrosion film formed on the electroless nickel deposit prepared using different stabilizers in NaCl solution
Authors: Cheong Woo‐Jae , Luan Ben L. , McIntyre N. S. , Shoesmith David W. 
Published: March 2007

AbstractX‐ray photoelectron spectroscopy (XPS) was used to examine the corrosion films formed on electroless nickel (EN) deposits prepared in an EN solution containing two different types and concentrations of bath stabilizers in Ar‐purged and oxygenated neutral 5% NaCl solution. Two distinctive corrosion films were observed after long periods of immersion. An enrichment of elemental phosphorus compared to nickel was observed on the surface of the EN deposit produced with no stabilizer and with maleic acid (MA). By comparison, a high degree of surface oxidation was observed on the EN deposit prepared with thiourea. Trace impurities of sulfur in the EN deposit prepared with thiourea appear to result in enhanced corrosion and, in turn, lead to the build‐up of corrosion products on the EN surface. By contrast, a P‐enriched chemical passivation layer was formed on the EN deposits prepared either without any stabilizer or with MA present. Copyright © 2007 Crown in the right of Canada, and John Wiley & Sons, Ltd.
Memory functioning following terror attack and the suggested immunization by religious faith
Authors: Gigi Ariela , Papirovitz Merav , Hagit Masika 
Published: March 2007

AbstractExposure to a terrorist attack is a traumatic experience that may result in elevated anxiety levels (DSM‐IV, 1994). Aspects of religiousness were found to be correlated with better mental health outcomes. This study assessed levels of anxiety and cognitive functioning in subjects who were exposed to terror attacks and correlated it with reported levels of religious faith. Thirty‐seven participants were recruited from religious settlements in the West Bank area in Israel. Fifteen subjects had been exposed to a terrorism event without developing predict post‐traumatic stress disorder and 22 controls had no such exposure. Learning and memory retrieval, for verbal and visual stimuli, were tested and the groups were compared. Half of the stimuli in each modality (verbal and visual) were rated as stressful, and half of them were rated as neutral. Responses and reaction times were recorded. Additionally, participants completed questionnaires to assess current anxiety and anxiety‐proneness and reported religiousness. Memory performance was found to be significantly lower for those exposed to terror attack, in comparison with the controls. The differences were significant for visual stimuli only and in particular for the stress‐related stimuli. The terrorism exposed group reported higher levels of state anxiety that was negatively correlated with levels of their reported religious faith. Although aspects of religiousness were found to be negatively correlated with current anxiety levels in the terrorism exposed group, this study did not show religious beliefs provided immunity against cognitive deterioration. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of rotor structural dynamics representations on the electrical transient performance of FSIG and DFIG wind turbines
Authors: Ramtharan Gnanasambandapillai , Jenkins Nicholas , Anaya‐Lara Olimpo , Bossanyi Ervin 
Published: March 2007

AbstractAn assessment of the impact that the representation of rotor structural dynamics has on the electrical transient performance of fixed‐speed induction generators (FSIGs) and doubly fed induction generators (DFIGs) wind turbines is presented. A three‐mass model that takes into account not only the shaft flexibility but also the blade flexibility in the structural dynamics is developed and used to derive an effective two‐mass model of the drive train dynamics, which represents the dominant natural frequency of vibration of the rotor structure. For the purposes of this investigation, the dynamic performance of both FSIG and DFIG wind turbines is evaluated during electrical transients such as a three‐phase fault in the network. The studies are conducted in the software code Bladed, where a detailed representation of the structural dynamics is used to derive the three‐mass model and the effective two‐mass model. Simulation results which illustrate how these representations of the rotor dynamics affect the response of the wind turbine during the fault are presented and discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Divalent Nickel and Monovalent Copper Pseudohalide Coordination Polymers Incorporating the Kinked Organodiimine 4,4′‐Dipyridylamine: From a (4,4)‐Type Lamellar Motif to an Unprecedented Staircase Morphology
Authors: Knapp Warren R. , Thomas Justin G. , Martin David P. , Braverman Maxwell A. , Trovitch Ryan J. , LaDuca Robert L. 
Published: March 2007

AbstractThe divalent nickel isothiocyanate coordination polymer [Ni(NCS)2(dpa)2] (1) has been prepared in high yield via the hydrothermal combination of Ni(SCN)2 with the kinked tethering ligand 4,4′‐dipyridylamine (dpa), and characterized via single crystal X‐ray diffraction, infrared spectroscopy and elemental and thermal analysis. 1 manifests offset stacked 2‐D (4,4)‐topology layered motifs organized into 3‐D via interlamellar supramolecular N–H···S hydrogen bonding. Hydrothermal reaction of CuCl2·2H2O, NaSCN, and dpa afforded the copper (I) thiocyanate coordination polymer [Cu2(SCN)2(dpa)] (2), whose single crystal structure revealed unprecedented 1‐D [Cu2(SCN)2] zig‐zag staircase motifs constructed via connection of the Cu2S2 “stair steps” at their adjacent sides via μ3‐1,1,3‐SCN anions. The 3‐D structure of 2 is propagated by covalent linkage of each [Cu2(SCN)2] staircase to four others through dipodal dpa tethering ligands, enhanced by N–H···S and C–H···S supramolecular interactions to two other staircases.
Polysulfonylamine. CLXXVIII Onium‐Salze des Benzol‐1,2‐di(sulfonyl)amins (HZ): Eine zweite Kristallform des Ammonium‐Salzes NH4Z·H2O und Kristallstruktur des Bis(triphenylphosphoranyliden)ammonium‐Salzes [Ph3PNPPh3]Z
Authors: Zerbe Eva‐Maria , Wölper Christoph , Roca Piñol Silvia , Jones Peter G. , Blaschette Armand 
Published: March 2007

AbstractPolysulfonylamines. CLXXVIII. Onium Salts of Benzene‐1,2‐di(sulfonyl)amine (HZ): A Second Crystal Form of the Ammonium Salt NH4Z·H2O and Crystal Structure of the Bis(triphenylphosphoranylidene)ammonium Salt [Ph3PNPPh3]ZA dimorphic form of NH4Z·H2O, where Z− is N‐deprotonated ortho‐benzenedisulfonimide, has been obtained and structurally characterized (previously known form 1A: monoclinic, P21/c, Z′ = 1; new polymorph 1B: monoclinic, P21/n, Z′ = 1). Both structures are dominated by an abundance of classical hydrogen bonds N+–H/O–H···O=S/OH2, whereby the anionic N− function does not act as an acceptor. The major difference between the dimorphs arises from the topology of the hydrogen bond network, which is two‐dimensional in 1A, leading to a packing of discrete lamellar layers, but three‐dimensional in 1B. Moreover, the latter network is reinforced by a set of weak C–H··O/N hydrogen bonds, whereas the layered structure of 1A displays only one independent C–H···O bond, providing a link between adjacent layers. The compound [Ph3PNPPh3]Z (2, monoclinic, P21/c, Z′ = 1) is the first structurally authenticated example of an ionic Z− derivative in which the cation contains neither metal bonding sites nor strong hydrogen bond donors. This structure exhibits columns of anions, surrounded by four parallel columns of cations, giving a square array. The large cations are associated into a three‐dimensional framework via weak C–H···C(π) interactions and an offset face‐to‐face phenyl interaction, while the anions occupy tunnels in this framework and are extensively bonded to the surrounding cations by C–H···O/N− hydrogen bonds and C–H···C(π) interactions.
Synthese und Kristallstrukturen von α‐ und β‐Ba3(PS4)2 sowie von Ba3(PSe4)2
Authors: Jörgens Stefan , Mewis Albrecht 
Published: March 2007

AbstractSynthesis and Crystal Structures of α‐, β‐Ba3(PS4)2 and Ba3(PSe4)2Ba3(PS4)2 and Ba3(PSe4)2 were prepared by heating mixtures of the elements at 800 °C for 25 h. Both compounds were investigated by single crystal X‐ray methods. The thiophosphate is dimorphic and undergoes a displacive phase transition at about 75 °C. Both modifications crystallize in new structure types. In the room temperature phase (α‐Ba3(PS4)2: P21/a; a = 11.649(3), b = 6.610(1), c = 17.299(2) Å, β = 90.26(3)°; Z = 4) three crystallographically independent Ba atoms are surrounded by ten sulfur atoms forming distorted polyhedra. The arrangement of the PS4 tetrahedra, isolated from each other, is comparable with the formation of the SO42− ions of β‐K2SO4. In β‐Ba3(PS4)2 (C2/m; a = 11.597(2), b = 6.727(1), c = 8.704(2) Å; β = 90.00(3)°; Z = 2) the PS4 tetrahedra are no more tilted along [001], but oriented parallel to each other inducing less distorted tetrahedra and polyhedra around the Ba atoms, respectively. Ba3(PSe4)2 (P21/a; a = 12.282(2), b = 6.906(1), c = 18.061(4) Å; β = 90.23(3)°; Z = 4) is isotypic to α‐Ba3(PS4)2 and no phase transition could be detected up to about 550 °C.
Na3F[WO4]: A Sodium Fluoride Ortho‐Oxotungstate(VI) with Strands of Face‐Shared Fluoride‐Centred Sodium Octahedra According to $^{1}_{\infty}\rm \{[FNa_{6/2}]^{2+}\}$
Authors: Hartenbach Ingo , Schleid Thomas 
Published: March 2007

AbstractDuring the reaction of Na2[WO4] with YF3 purposed to yield fluoride‐derivatized yttrium oxotungstates(VI), colourless platelet‐shaped single crystals of Na3F[WO4] emerged as main product. The title compound crystallizes orthorhombically in the space group Pnma (a = 559.59(5), b = 751.02(7), c = 1285.98(9) pm) with four formula units per unit cell. Besides isolated ortho‐oxotungstate units [WO4]2− (d(W–O) = 176–178 pm) the crystal structure contains two crystallographically independent Na+ cations which are both octahedrally coordinated by four oxygen atoms and two fluoride anions. The F− anions are surrounded by six sodium cations (d(F–Na) = 224–242 pm) also in an octahedral fashion. These octahedra built up chains along [100] by sharing trans‐oriented faces according to $^{1}_{\infty}\rm \{[FNa_{6/2}]^{2+}\}$, which are stacked according to a hexagonal closest rod‐packing. The cationic strands are surrounded, interconnected and charge‐balanced by isolated [WO4]2− tetrahedra with almost ideal shape and every O2− ligand is terminally coordinated by three Na+ cations.