bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of lattice mismatch upon defects generation and luminescent characteristics of heterostructures in the GaP‐InP system
Authors: Konnikov S. G. , Popova T. B. , Ruvimov S. A. , Sobolev M. M. , Sorokin L. M. , Shulpina I. L. , Umansky V. E. 
Published: July 2007

AbstractThe influence of lattice mismatch and thermal stresses on the defect generation in GaAs‐GaInP heterostructures was studied. The results of electron‐probe, X‐ray topographic and electron‐microscopic investigations are presented. The comparison of X‐ray diffraction and microcathodoluminescence results is done.
Effect of generated defects during plastic deformation on electron properties of silicon
Authors: Mąkosa A. 
Published: July 2007

AbstractConductivity, photoconductivity and SDP of n‐type silicon deformed and annealed under different thermal conditions were investigated. The conductivity was found to be dependent on the temperature of deformation and additional annealing. Recombination in deformed samples is fully controlled by paramagnetic centers localized within the charge space region around the dislocations.
Metastable zone of sodium hydrogen carbonate crystallization in ammonia‐soda process
Authors: Filipescu L. , Szanto M. , Filpescu M. 
Published: July 2007

AbstractExperimental results of an investigation of metastable zone and sodium hydrogen carbonate nucleation from the included supersaturated solutions are presented. In order to attain a better crystal size distribution some temperature patterns along the cooling part of the carbonating column have been suggested. It has been shown that high crystal growth rates might be carried on smaller size carbonating columns.
Determination of distribution coefficients from measurements of mean absorption coefficients of foreign ions along the crystal growth axis distribution coefficients of complex ions in CsI crystals
Authors: Bollmann W. 
Published: July 2007

AbstractAn formula connecting the absorption coefficient α with the distribution coefficient k of ions is obtained by integrating PFANN'S formula and by inserting Beer's relation. It allows the determination of k of absorbing ions by measurements of α along the crystal growth axis for extended crystal regions. The distribution coefficients of BO2−, CNO−, CO3− −, IO3−, NH4+, NO2−, NO3−, OH−, and SO4− − ions in CsI crystal were determined by this method. The relations between absorption constants and concentrations are given for most of these ions.
On the reversion behaviour of an Al‐15 at.% Zn alloy between 155°C and 175°C
Authors: Wendrock G. , Löffler H. 
Published: July 2007

AbstractThe structural changes going on in an Al‐15 at.% Zn alloy postaged in the vicinity of the kink of the C‐curve (161°C) in the T.T.T.‐diagram after pre‐ageing at R. T. or 90°C (till start radii rS between 1.0 and 4.0 nm were obtained) were followed by means of SAXS‐investigations. The main results are the following:

No indication could be found that the reversion behaviour is remarkably changed by crossing the temperature of the kink of the C‐curve in the T.T.T.‐diagram, i.e. the reversion as well as the growth mechanism of the zones does not differ considerably below and above 161°C.
The decrease of the integral intensity Q0 during the reversion process is mainly due to both the loss of zinc content of the zones and its rise in the matrix and not essentially by the diminution of the volume fraction of the precipitates.
Zones of a start radius of about 4 nm are much more stable against the decrease of the zine content during the reversion treatment that those of 2 nm.
Influence of impurity on rhythmic crystallization of calcium carbonate in agar gel
Authors: Krishnan S. , Gnanam F. D. , Ramasamy P. , Laddha G. S. 
Published: July 2007

AbstractDuring the gel growth of calcite crystals in test tubes, for a narrow concentration of inner and outer electrolytes we observed rhythmic crystallization of calcium carbonate. In this paper the effect of adding impurities on the pattern of periodic crystallization of calcium carbonate has been presented. The addition of impurities either increases or decreases the solubility of reaction product and hence may affect the rate of nucleation of calcium carbonate crystals. The variation of spacing coefficient and velocity constant due to the addition of impurities has also been studied.
On temperature dependence of Debye‐Waller factor in V3Si in the temperature range from 8 to 293 K
Authors: Sirota N. N. , Polutchankina L. P. 
Published: July 2007

AbstractThe temperature dependence of the Debye‐Waller factors of vanadium and silicon in V3Si and that of the X‐ray Debye temperature are obtained from the integral intensities of X‐ray reflection measured at 11 temperatures ranging from 8 K to 293 K. It shown that the breaks on these curves are observed at Tbr = 21.7 K. This fact allows to assume that the phase transition in this compound is accompanied by the rapid change of the atomic vibration frequencies.
HVEM In‐situ Straining Experiments on MgO Specimens Predeformed at High Temperature
Authors: Appel F. , Berezhkova G. V. , Messerschmidt U. , Perstnev P. P. , Rozhanskii V. N. 
Published: July 2007

AbstractA deformation of MgO crystals at high temperature significantly increases the plasticity in a subsequent deformation at room temperture. It was shown by deformation experiments inside the high voltage electron microscope the this effects is most probably due to the homogeneous dislocation structure formed by straining at high temperature, but not to change in the processes controlling the mobility of individual dislocations.
Reorientation of the long molecular axis in smectic phases
Authors: Kresse H. , Selbmann Ch. , Demus D. , Buka A. , Bata L. 
Published: July 2007

AbstractThe low frequency dielectric dispersion was measured of two 4‐n‐alkyloxybenzylidene‐4′‐n‐hexylaniline in nematic, smectic A, C, B, F, and G phases. The results were discussed with respect to the molecular structure and the relaxation mechanism.
Synthetic, X‐ray Diffraction, Electrochemical, and Density Functional Theoretical Studies of (Indenyl)ruthenium Complexes Containing Dithiolate Ligands
Authors: Ng Sin Yee , Tan Jialin , Fan Wai Yip , Leong Weng Kee , Goh Lai Yoong , Webster Richard D. 
Published: June 2007

AbstractHalide substitution of the complexes [(Ind)Ru(L2)X] {Ind = η5‐C9H7. 1: (L2) = dppf [1,1′‐bis(diphenylphosphanyl)ferrocene], X = Cl; 2: (L2) = dppm [1,1′‐bis(diphenylphosphanyl)methane], X = Cl; and 18: (L2) = (CO)2, X = I} with the 1,1‐dithiolates –S2CNR2 (dialkyl dithiocarbamates for R = Me, Et, and C5H10), –S2COR (alkyl xanthates for R = Et and iPr), and–S2PR2 (dithiophosphinates for R = Et and Ph) showed that the lability of the indenyl ligand is influenced by the nature of both the coligand and the incoming dithiolate, as well as the solvent. In addition to dithiolate derivatives, the reactions also produced the hydride species [(Ind)Ru(diphos)H] in solvent‐ and stoichiometry‐dependent yields. The observed dependence of lability of Ind on (L2) follows the order, dppf < dppm ≈ (CO)2, in agreement with the electron‐donor capability of L2, as well as the estimation of lowest activation energy for the η5 → η3 ring slippage process in the series of complexes [(Ind)Ru(L)2(S2COMe)] (L = PMeH2, PH3, CO) for L = CO. The computational study also indicated an indenyl lability order for dithiolate substitution (dithiocarbamate > xanthate), in agreement with experimental findings. The dissociation of the indenyl ligand in chloro substitution of 1 by –S2CNEt2 was found to be exhaustive in a polar solvent like MeOH, but only partial in CH2Cl2. Cyclic voltammetry experiments indicated that [(Ind)Ru(dppf)(η1‐S2COiPr)] (10) and [(Ind)Ru(dppf)(η1‐S2PPh2)] (13) can be oxidized in one‐electron chemical irreversible or chemical reversible processes, respectively (at a scan rate of 100 mV/s), at about 0 V versus Fc/Fc+. Complex 13 underwent additional one‐electron oxidation processes at +0.5 and +0.8 V versus Fc/Fc+. The new complexes have all been characterized spectroscopically, and some (four containing the indenyl ligand and three of the non‐indenyl type) by X‐ray diffraction as well. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Preparation of Cu2O Hollow Nanospheres under Reflux Conditions
Authors: Yang Muquan , Zhang Yingwei , Pang Guangsheng , Feng Shouhua 
Published: June 2007

AbstractCuprous oxide hollow nanospheres were prepared by heating a solution of copper acetate and hydrazine as a reductant in 2‐propanol at reflux. The size distribution of the nanospheres is mainly in the range 100–200 nm. The products were characterized by X‐ray diffraction, UV/Vis diffuse reflectance spectroscopy, SEM, and TEM. The results indicated that the Cu2O hollow nanospheres aggregated from small nanoparticles with an average size of ca. 6.6 nm. The UV/Vis diffuse reflectance spectrum indicated that the optical absorption edge of the hollow Cu2O nanospheres is redshifted relative to their solid counterparts. The influence of the reaction conditions, such as reaction temperature, reaction time, and the amount of water, on the formation of the nanospheres as well as their morphology were studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Crystal Structure and Surface Photovoltage Properties of MnII Coordination Supramolecules
Authors: Sun Li‐Ping , Niu Shu‐Yun , Jin Jing , Zhang Li 
Published: June 2007

AbstractThree MnII coordination supramolecular complexes [Mn(pdc)(H2O)]n 1, {[Mn(pdc) (phen)(H2O)]·3H2O}n 2, and {[Mn(cyan)2(H2O)4]·2HCl·2(Hcyan)} 3 (H2pdc = pyridine‐2,3‐dicarboxylic acid, Hcyan = cyanuric acid, phen = 1,10‐phenanthroline) were hydrothermally synthesized and their structures determined by single‐crystal X‐ray diffraction. The pdc group in complex 1 bridges the MnII ions to form an infinite 3D structure. In complex 2, the MnII ion is bridged to a 1D infinite chain by pdc groups and the chain is further connected to a 2D structure by hydrogen bonds. The 3D structure of complex 3 is formed by hydrogen bonds and O···Cl weak interactions. Surface photovoltage spectroscopy (SPS) of complexes 1–3 indicate that they all possess positive SPV response in the range of 300–800 nm and show p‐type semiconductor characteristic. The intensities of the SPV responses are obviously different, and this can mainly be attributed to the differences in their structures. Field‐induced surface photovoltage spectroscopy (FISPS) of complexes 1–3 confirms their p‐type semiconductor characteristic.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Carbon and Silica Hollow Spheres with Mesoporous Shells using Polyethylene Oxide/Phenol Formaldehyde Polymer Blend
Authors: Chang‐Chien Chun‐Yi , Hsu Chun‐Han , Lee Tsung‐Ying , Liu Che‐Wei , Wu Sheng‐Ho , Lin Hong‐Ping , Tang Chih‐Yuan , Lin Chin‐Yen 
Published: June 2007

AbstractPolyethylene oxide/phenol formaldehyde silica composite hollow spheres were obtained from a fast silicification of a polymer blend, containing polyethylene oxide (PEO) as silica gelator and phenol formaldehyde (PF) polymer as carbon source, in a highly diluted silica solution at pH ≈ 5.0–6.0. The PF–PEO/silica hollow spheres can be feasibly converted to mesoporous silica hollow spheres by hydrothermal treatment and calcination, and to mesoporous carbon hollow spheres after pyrolysis under a nitrogen atmosphere and silica etching. Because the formation of the hollow spheres is kinetically controlled, the diameter of the hollow spheres is dependent on the molecular weight of the PEO polymer, pH value of the silica solution, and the PF content, and the size can be tuned within a range of a few micrometers to tens of nanometers. These mesoporous hollow spheres have high surface areas and large pore sizes and volumes. In practice, the mesoporous carbon hollow spheres with an interconnected mesostructure were used as a solid template to prepare different metal oxide hollow spheres. After impregnation of the proper metal oxide precursors and calcination, the γ‐Al2O3, anatase‐TiO2, α‐Fe2O3, ZrO2, MgO, and CeO2 hollow spheres composed of nanoparticles were readily synthesize.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Enantioselective analysis of the antipsychotic 9‐hydroxyrisperidone, main metabolite of risperidone, by chiral capillary EKC using dual CDs
Authors: Danel Cécile , Chaminade Pierre , Odou Pascal , Bartélémy Christine , Azarzar Dalila , Bonte Jean‐Paul , Vaccher Claude 
Published: June 2007

AbstractAn analytical method for the enantioseparation of the 9‐hydroxyrisperidone, main metabolite of the antipsychotic risperidone (Risp), was developed by CD‐EKC in the dual CDs mode using anionic and neutral CDs at acidic pH 2.5. Preliminary experiments allowed us to select the more suitable couple of CDs composed of sulfated‐α‐CD and hydroxypropylated‐β‐CD. The optimization of the main experimental parameters (concentrations of both CDs and concentration of the phosphate buffer) was based on a central composite design through the response surface methodology. Then, the influence of the voltage and the temperature on the enantioseparation was studied using the classical univariate approach. The final method permits to resolve the enantiomers of the 9‐hydroxyrisperidone with a resolution of 3.13 and an analysis time of about 13 min. Finally, this method was successfully applied for the simultaneous determination of Risp and the enantiomers of 9‐hydroxyrisperidone (9‐OHRisp).
In vitro evaluation of the genotoxicity of acetamiprid in human peripheral blood lymphocytes
Authors: Kocaman Ayşe Yavuz , Topaktaş Mehmet 
Published: June 2007

AbstractAcetamiprid, a neonicotinoid insecticide, is commonly used both in agriculture and domestic areas against a wide range of insects. The potential genotoxicity of a commercial formulation of acetamiprid (Mosetam 20 SP, containing 20% acetamiprid as the active ingredient) on human peripheral blood lymphocytes was examined in vitro by sister chromatid exchange (SCE), chromosomal aberrations (CAs), and micronucleus tests. Cells were treated with 25, 30, 35, and 40 μg/ml of acetamiprid for 24 and 48 hr. Acetamiprid induced SCEs and CAs significantly at all concentrations and treatment times and micronucleus formation was significantly induced at 30, 35, and 40 μg/ml of acetamiprid as compared with both the control and solvent control. Acetamiprid decreased the proliferation index (PI) at the two highest concentrations (35 and 40 μg/ml) for the 24‐hr treatment period and only at the highest concentration (40 μg/ml) for the 48‐hr treatment period when compared with the control and solvent control. Peripheral lymphocytes exposed to all concentrations of acetamiprid showed significant decreases in mitotic index (MI) and nuclear division index (NDI) for both treatment periods when compared with both the control and solvent control. Furthermore, acetamiprid decreased the MI in both treatment periods, and the NDI only in the 24‐hr treatment period to the same extent as the positive control, mitomycin C (MMC). This study presents the first in vitro evidence for the genotoxicity of a commercial formulation of acetamiprid in human peripheral lymphocytes. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
Forecasting relative quality
Authors: Uri Noel D. 
Published: July 2007

AbstractThis paper develops a model to forecast the likely quality rating of new automobiles. A scheme is devised and implemented for 1982 whereby the probability that a specific model will have one of five quality ratings is computed. The quality ratings are based on the trouble index computed by Consumer Reports based on a survey of its subscribers. A multinomial logit specification is used whereby the relative probability that a given level of quality is realized is a function of previous quality ratings, the location of the manufacturer of the automobile, the size of the automobile and the list price (or port‐of‐entry prices, in the case of imports). The forecast results when compared in a qualitative way to actual 1982 quality ratings prove to be acceptable.
An empirical investigation of combinations of economic forecasts
Authors: Holden K. , Peel D. A. 
Published: July 2007

AbstractThis paper examines the effects of combining three econometric and three times‐series forecasts of growth and inflation in the U.K. If forecasts are unbiased then a combination exploiting this fact will be more efficient than an unrestricted combination. Ex post econometric forecasts may be biased but ex ante they are unbiased. The results of the study are that a restricted linear combination of the econometric forecasts is superior to an unrestricted combination and also to the unweighted mean of the forecasts. However, it is not preferred to the best of the individual forecasts.
Long‐term forecasting with innovation diffusion models: The impact of replacement purchases
Authors: Kamakura Wagner A. , Balasubramanian Siva K. 
Published: July 2007

AbstractThe model presented in this paper integrates two distinct components of the demand for durable goods: adoptions and replacements. The adoption of a new product is modeled as an innovation diffusion process, using price and population as exogenous variables. Adopters are expected to eventually replace their old units of the product, with a probability which depends on the age of the owned unit, and other random factors such as overload, style‐changes etc.It is shovn that the integration of adoption and replacement demand components in our model yields quality sales forecasts, not only under conditions where detailed data on replacement sales is available, but also when the forecaster's access is limited to total sales data and educated guesses on certain elements of the replacement process.
Decision‐analytic assessment of the economic value of weather forecasts: The fallowing/planting problem
Authors: Katz Richard W. , Brown Barbara G. , Murphy Allan H. 
Published: July 2007

AbstractA decision‐analytic approach is taken to the problem of assessing the economic value of imperfect weather forecasts. Emphasis is placed on measures of the quality of such information and on the relationship between quality and economic value. The fallowing/planting problem for a spring wheat farmer is examined in detail as a specific application. It is assumed that the farmer's goal is to maximize the total expected discounted return over an infinite horizon, which places this problem within the general framework of Markov decision processes. By means of stochastic dynamic programming, the economic value to the farmer of currently available seasonal precipitation forecasts, as well as of hypothetical improvements in the quality of such forecasts, is estimated. Because the relationship between the quality and value of forecasts is highly nonlinear, the need to explicitly determine value‐of‐information estimates, rather than relying on quality as a surrogate for value, is made clear.
Small sample properties of quarterly forecast errors
Authors: Sankaran S. 
Published: July 2007

AbstractThere are two basic approaches used in the comparative evaluation of forecasters: (1) Statistical tests of significance of differences in error measures, (2) Ordinal rankings of forecasters. To use the first approach of statistical tests, the forecast error data must satisfy the assumptions underlying those tests. This paper examines the validity of those assumptions by enquiring into the small sample properties of the forecast error data of quarterly forecasts of the U.S. economy.
The impact on the performance of growth curve models of changes in parameter re‐estimation period and other factors
Authors: Price D. H. R. , Sharp J. A. 
Published: July 2007

AbstractA simulation model of a real electricity supply undertaking was used to provide a financial performance measure for growth curve forecasting models. The impact on financial performance was determined when changes were made in (1) the method of estimating the model parameters, (2) the period between re‐estimations, (3) the growth curve fitted and (4) the amount of smoothing of the demand time‐series. The response to variation of the parameter review period was found to behave surprisingly, in that it exhibited different signs for two different estimation methods. Changes in re‐estimation period explained somewhat more of the variation in performance than did a change in growth curve. Correcting the demand series for conditions which were known to be abnormal improved performance.
Should fixed coefficients be re‐estimated every period for extrapolation?
Authors: Swamy P. A. V. B. , Schinasi Garry J. 
Published: July 2007

AbstractThis paper demonstrates that forecast accuracy is not necessarily improved when fixed‐coefficient models are sequentially re‐estimated and used for prediction, after updating the database with the latest observation(s). It is argued that although sequential estimation may minimize the variances of predictors based on some classes of estimators, sequential estimation does not necessarily yield accurate predictions (i.e. predictions that are close to actual realizations). Minimizing the mean squared prediction error about the actual realization is a necessary condition for maximizing the probability that one predictor is more accurate than others. This minimization need not require, and may even exclude, the most recent data. It has been shown by an example that a prediction based on a nonsequential estimate of a stochastically varying coefficient model is superior to predictions based on several sequential estimates of the fixed‐coefficient models, including a random walk model.
On multistep prediction error methods for time series models
Authors: Stoica Petre , Nehorai Arye 
Published: July 2007

AbstractMultistep prediction error methods for linear time series models are considered from both a theoretical and a practical standpoint. The emphasis is on autoregressive moving‐average (ARMA) models for which a multistep prediction error estimation method (PEM) is developed. The results of a Monte Carlo simulation study aimed at establishing the possible merits of the multistep PEM are presented.
A constrained least squares method for estimating the effects of an unknown monotonically intervening factor
Authors: Thore Sten 
Published: July 2007

AbstractA constrained least squares method is developed for the estimation of the effects of an unknown intervening causal factor in regression analysis, when the unknown factor shifts the regression hyperplane monotonically upwards (downwards) over time. As an illustration, we estimate the price elasticity of cigarettes in the USA and the systematic shifts of the demand curve for cigarettes during the time period 1964‐86 (these shifts presumably reflecting the heightened awareness of the general public of the potential dangers of smoking).
Judgmental extrapolation and the salience of change
Authors: Andreassen Paul B. , Kraus Stephen J. 
Published: July 2007

AbstractPeople may often forecast using cognitive procedures that resemble formal time‐series extrapolation models. A model of judgmental extrapolation based on exponential smoothing is proposed in which the setting of the trend parameter is hypothesized to depend upon the relative salience of the successive changes. The salience hypothesis was first tested with exponential series by the use of a framing manipulation. As predicted, focusing the subjects' attention on the changes led to more accurate forecasts. In two investment simulation studies, the salience hypothesis was further examined by varying the statistical properties of the price changes. As predicted, subjects were more likely to sell as prices fell and to buy as prices rose (1) as the sample size of similar changes increased; (2) when the variance of the changes was low; and (3) when the absolute value of the mean change was high. Conditions that may influence judgmental forecasting processes are discussed.