bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical defects in barium—strontium niobate single crystals
Authors: Kopylov Yu. L. , Kravchenko V. B. , Moiseev V. P. 
Published: July 2007

AbstractThe distributions of edge dislocations and residual mechanical stresses in BaxSr1‐xNb2O6 (BSN) crystals are investigated and the explanation of the nature of the “growth column” is proposed. The “growth column” is a defect zone going through all of the crystal and usually repeating in its cross‐section the contour of the seed crystal. The “growth column” boundary is the closed contour with extremely high edge dislocation density. These dislocations are connected with thermal stresses due to seed‐melt contact or abrupt crystal widening. Under proper crystal seeding and widening conditions one can obtain the BSN crystals with dislocation densities less than 10 cm−2 and without the “growth column”.The method of chemico‐mechanical polishing of BSN crystals not forming a defect layer on the surface of the crystals have been developed. The high temperature diffusion annealing is shown to eliminate the growth striae in BSN crystals.
Cryoscopic Investigation of Lead Oxide Mixtures with Garnet Forming Oxides, Garnets, and Related Oxide Compounds
Authors: Fischer K. 
Published: July 2007

AbstractThe freezing point depression of PbO as solvent caused by the trivalent oxides and oxide compounds Fe2O3, Ga2O3, Al2O3, Bi2O3, Y2O3, Gd2O3, La2O3, YFeO3, Fe3O4, Y3Fe5O12, Gd3Ga5O12, and PbFe12O19 allows to determine the number of particles which are formed from these compounds in the diluted solutions. — We have measured the liquidus temperatures of binary mixtures with the help of a DTA‐equipment. In this way the cryoscopic constant K̄c = 121 ± 16 K · kg · mole−1 of PbO was determined by addition of ZnO, Cu2O, PbSO4, and PbF2, respectively. The experimental results show that the oxides and oxide compounds dissociate in particles which contain only one cation of the solved compound.
Principles of the Design of Straining Stages
Authors: Messerschmidt U. , Appel F. 
Published: July 2007

AbstractThe paper describes the elastic properties of tensile stages for the HVEM. The quality of the force control depends on the accuracy of the drives related to the maximum elongation as well as on the elastic compliance of the stage. The best accuracy of the load is obtained in soft stages. The fundamental operation of a soft and a hard stage is reviewed. These stages use a special thermal drive.
The Influence of the Specimen Surface on Thermally Induced Structural Changes
Authors: Köster U. 
Published: July 2007

AbstractTransmission electron microscopy has been particularly fruitful for studying phase transformations and other thermally induced structural changes. Investigations of such reactions can be carried out either by in‐situ hot stage electron microscopy using thin foils or by monitoring the structure after various times of annealing of bulk specimens outside the microscope. Observations after annealing clearly provide no information about the temporal relationship between changes which have occurred. Dynamic studies in the microscope are capable of providing this information, however, the proximity of the foil surface is a complicating factor.
On the characterization of electrically active inhomogeneities in semiconductor silicon by charge collection at schottky barriers using the SEM‐EBIC (I). Fundamentals and contrast due to macroscopical inhomogeneities
Authors: Kittler M. 
Published: July 2007

AbstractThe physical processes are explained for understanding of the EBIC‐method with direct irradiated schottky barriers, followed by description of preparation. The imagening of macroscopical inhomogeneities (striations, lifetime‐striae) is shown as an application in this Ist part. Finally contrasts are discussed, which are caused by preparation or by surface unevenness respectively, but not by inhomogeneities of the material.
The growth of HgI2 crystals
Authors: Gospodinov M. 
Published: July 2007

AbstractThe paper presents a system for αHgI2 crystal growth by the temperature oscillation method. The system has a capability of crystal growing at an excess I2 or Hg vapour pressure. Optimum conditions for producing crystals up to 2 cm3 by volume have been established. The crystals grown at an excess I2 vapour pressure have higher resistivity and higher drift electron and hole mobilities — μe = 120 cm2 V−1 s−1 and μh = 6 cm2 V−1 s−1, respectively.
Absorption and ionic conductivity of oxygen‐containing SrF2 crystals
Authors: Bollmann W. 
Published: July 2007

AbstractAn absorption band at 3644 cm−1 is caused by isolated OH− ions. O− ions cause an absorption band at 213 nm the oscillator strength of which is 0.020. Charge‐compensation of O− ions is effected by F− ion vacancies (F). As for CaF2 crystals there occur monomers and dimers of [O− – F] complexes. The mass action constants of association of F with oxygen centres are KAD = ⅓ exp (4.28 – 0.82 eV/kT) for [O− – F], KAT = 4 exp (17.4 – 1.25 eV/kT) for [2 O− – F] and KAQ = exp (4.2 – 0.89 eV/kT) for [2 O− – 2 F].
The Goldschmidt complication series, morphological extinction rules and phase relationships. A contribution to correspondence between crystal structure and habitus
Authors: Follner H. , Schwarz H. 
Published: July 2007

AbstractFor space group Pbn21 and organic structures with one acentric molecule in the asymmetric unit it has been demonstrated, that the morphological lattice is a Fourier transform of crystal morphology. The morphological lattice corresponds with the lattice of the centers of molecules.
An electrolytic method to grow copper dendrites and single crystals in gels
Authors: George M. T. , Vaidyan V. K. 
Published: July 2007

AbstractA new electrolytic method for the growth of any metallic crystal in gel by using gel as a medium for controlled growth, is reported. Different types of large dendrites and single crystals of copper were grown by electrolytic method in the gel medium. It is found that pH of the gel medium, the concentration of the supernatant solution, the current density and the electrode material used, have considerable influence on the habits of the dendrites and the single crystals thus grown. The surface features and morphology of crystals and dendrites were studied by optical and scanning electron microscopy. Compared to other conventional electrolytic growth techniques, the present method has a number of additional parameters that can be varied, and hence a more effective controlled growth of crystals is possible.
Investigation of InAs—InSb solid solution heteroepitaxial layers and structures
Authors: Bert N. A. , Zhingarev M. Z. , Konnikov S. G. , Mursakulov N. M. , Tretyakov D. N. 
Published: July 2007

AbstractThe results of investigations concerning the peculiarities of obtaining InAs—InAs1−xSbx heterostructure and of its properties revealed that the quality of epitaxial layers as well as photoelectric and electroluminescent device structure characteristics are to a great extent determined by a disagreement magnitude of heterostructure materials. — To decrease the magnitude of disagreement at the layer‐substrate boundary and to achieve the composition with x > 0.1 at some distance the method of layer‐by‐layer growth (ANDREWS et al.) and the obtaining a graded heterojunction with optimization of component distribution along epilayer thickness seems to be promising.
Structure information from morphological data of organic crystals with the help of Patterson methods
Authors: Follner H. 
Published: July 2007

AbstractThe morphological points of a space group are special or general point configurations, respectively combinations of point configurations. There are mainly point configurations to be found, which in three‐dimensional space or at least in one projection, posses a higher translational symmetry than the crystallographic ones. The morphological lattice of organic structures with one molecule in the asymmetric unit e. g. corresponds to the lattice of the centers of gravity of molecules. Starting from the faces appearing on crystal, a possibility for deriving structure information with the help of Patterson methods will be demonstrated.
Vickers hardness and microfracture of single and polycrystalline Al2O3
Authors: Krell A. 
Published: July 2007

AbstractVarious methods were tested with respect to their qualification for the hardness determination of sapphire and sintered alumina. From the load and time dependence of the hardness of different ceramic structures we get informations about the acting deformation mechanisms. Local plastic deformation and brittle microfracture are of importance for the room temperature behaviour of this basic oxide ceramic.
Growth and etching of anhydrous diglycine sulfate single crystals
Authors: Pandaya G. R. , Vyas D. D. 
Published: July 2007

AbstractSingle crystals of anhydrous diglycine sulfate are grown at constant temperature by evaporation method. The crystals are grown at various temperatures and their growth rate is determined. A chemical etchant for dislocation studies is reported. The perfection of the crystals grown at various temperatures has been studied using etching technique. It is found that the crystals contained inclusions of the mother liquid. The crystals grown below 28° are almost free of inclusions and the dislocation density is also low.
Mechanism of epitaxial ferrite‐spinel layer formation on magnesium oxide substrate
Authors: Aleksandrov L. N. , Mitlina L. A. , Molchanov V. V. 
Published: July 2007

AbstractThe initial stage of small gap heteroepitaxial growth of magnesium‐manganese ferrite films during chemical gas transportation reactions on orientation (100) magnesium oxide substrate was studied.Film growth would begin with origination of parallely oriented three‐dimensional nuclei, their shapes at lower (1170 K) and at appear (1420 K) film synthesis temperature limits being different.After little islands had grown together and continuous layer formed the secondary nuclei would appear, their shapes resembling cut‐up pyramids.Continuous layer minimum thickness was 0.15 μm. The growing together of little islands results in film block structure. Block sizes could be as big as 300–400 μm if films grow at the speed of 2 μm/min, the density of islands being 106 cm−2.Linear density of unconformity dislocations at film‐substrate boundary would be (3.7 ÷ 7.4) 103 cm−1. It would depend on magnesium content for a film.Elastic stresses in films would come to 7 · 108 ÷ 3 · 109 dyne/cm2.X‐ray topography pictures of block structures and of accumulations of admixtures at block boundaries are presented.
Structural changes of NaCl and Si single crystal surfaces under ion bombardment
Authors: Marinov M. , Stoyanchev R. 
Published: July 2007

AbstractThe surface structural changes under ion bombardment of NaCl and Si monocrystalline specimens are followed using electron microscopic technique. Formations and regions with circular symmetry are registered on the surface of NaCl and Si single crystals. Qualitative interpretation of the generation mechanism of the circular formations is made. The ion bombardment is used for the visualization of the surface structure of the specimens by the method of crystal selfdecoration.
Defect structure and the nature of the obstacles for dislocations in NaCl(Ca) crystals
Authors: Urusovskaya A. A. , Darinskaya E. V. , Voszka R. , Jansky J. 
Published: July 2007

AbstractOn the basis of the investigation of the influence of Ca concentration on yield point at different strain rates it is revealed the nature of the obstacles for dislocations overcomed with and without thermal activation.
Configuration entropy of ternary alloy superlattice
Authors: Šrobár F. 
Published: July 2007

AbstractDifference in mixture‐related entropy between superlattice and the corresponding homogeneous crystal in which all composition gradients have been annihilated by equilibrating processes (the configuration entropy of superlattice, ΔSconf) is analytically formulated as a function of composition variables and geometry parameters. Numerical evaluations are performed for the important case of AlxGa1−xAs‐based superlattice. Qualitative trends confirm in general the intuitive expectations (− ΔSconf grows with increasing composition difference between the layers); the dependencies on geometry parameters exhibit a peculiar behaviour. The results are applicable to superlattices with periode lengths sufficiently in excess of the monoatomic layer thickness.
Calorimetric investigations of 2‐[4‐n‐alkylphenyl]‐5‐[4‐n‐alkyloxyphenyl]‐pyrimidines
Authors: Wiegeleben A. , Marzotko D. , Demus D. 
Published: July 2007

AbstractWe investigated temperatures and enthalpies of the phase transitions by means of the calorimeter DSC‐2. The kinetics of polymorphic transitions in the solid state, the pretransitional behaviour in the liquid crystalline phases and the transition enthalpies, ranging from 3 J/mol up to 50 kJ/mol, in relation to the occurrence of the liquid crystalline phase types SG, SF, SC, SA, and N are points of discussion.
Estimation of activation parameters for diffusion‐controlled crystallization of barium tungstate from sodium tungstate melts by differential thermal analysis
Authors: Roy B. N. , Roy M. R. 
Published: July 2007

AbstractThe proximity (d12) between a diffusing species and its host crystal necessary for a successful diffusion for diffusion‐controlled crystallization of barium tungstate from sodium tungstate melts in platinum crucibles was estimated. These distances increased with increased cooling rates (RT) and crystallization temperatures (T0). Energy (E), enthalpy (ΔHa), entropy (ΔSa) and free‐energy (ΔGa) of activation and the pre‐exponential factor (k0) were evaluated using an ordinary Arrhenius equation kD1 = k0e−E/RT, where kD1 was the diffusion rate‐constant. These parameters were virtually unaffected by the changes in T0 and RT.
Accuracy in forecasting: A survey
Authors: Mahmoud Essam 
Published: July 2007

AbstractIn this study, the author provides a brief and concise summary of empirical investigations pertaining to forecasting with special reference to the accuracy of different forecasting techniques. The study mainly focuses on comparisons of the accuracy of these techniques. The comparisons cover both quantitative and qualitative methods. In addition the summary includes studies seeking to test or improve accuracy by combining forecasting techniques.
Discount weighted estimation
Authors: Ameen J. R. M. , Harrison P. J. 
Published: July 2007

AbstractThe parsimonious method of exponentially weighted regression (EWR) is attractive but limited in application because it depends upon just one discount factor. This paper generalizes the EWR approach to a method called discount weighted estimation (DWE) which allowed distinct model components to have different associated discount factors. The method includes EWR as a special case. The general non‐limiting recurrence relationships will be useful in practice, especially when practitioners wish to specify prior information, to intervene with subjective judgement and to derive estimates and forecasts sequentially based upon limited data. Two theorems extend the important EWR limiting results of Dobbie and McKenzie to DWE. The latter permits the derivation of a large class of known processs for which DWE is optimal. The method is illustrated by two applications, one of which uses the famous international airline passenger data. This allows a comparision with the ICI MULDO system which uses a particular two discount factor forecasting method. A companion paper extends the discount methods to Bayesian forecasting, Kalman filtering and state space modelling.
The M‐competition with a fully automatic box–jenkins procedure
Authors: Libert G. 
Published: July 2007

AbstractCAPRI is a fully automatic and quick procedure for forecasting. It is based on the Box–Jenkins methodology and needs no a priori knowledge about the time series. The 1001 series of the Makridakis competition have been analysed with this program and its accuracy measured in comparison with other methods. CAPRI is recommended for short term forecasting horizons in cases where the user does not want to interfere with the modelling process.
The chatfield‐prothero case study: Another look
Authors: Raveh Adi 
Published: July 2007

AbstractThe Chatfield‐Prothero case study in time series, ‘Sales of a company X’, is analysed from a perspective different to that of the authors. More accurate forecasting performance for these data is obtained by adopting the following two tactics: (1) shifting from a problem in transformation of the original series to one of seasonality adjustment; (2) assuming a mixed seasonality type model in contrast to employing a multiplicative assumption.
Forecasting system energy demand
Authors: Guinel Ipek 
Published: July 2007

AbstractThis paper presents the results of the Electric Power Research Institute Short Range Forecasting Project (EPRI‐SRF) performed by the Load Forecasts Department, Economics and Forecasts Division of Ontario Hydro, Ontario, Canada.In this study a variety of short‐range forecasting techniques are applied to Ontario Hydro monthly data on total system energy demand. These techniques are available in a software package (FORECAST MASTER) developed for EPRI by two consultants—Scientific Systems, Inc. (SSI) and Quantitativ Economic Research, Inc. (QUERI).The methods used for this study were the univariate Box‐Jenkins method, the multivariate state‐space method, Bayesian vector autoregression and autoregress ve econometric regression.A comparison of the models developed show that the econometric models perform the best overall. The state‐space models are more suitable for very short‐term (one‐step ahead) forecasts. Although the Box‐Jenkins method has the advantage of simplicity in terms of estimation and data requirement, its performance was not as good as that of the others. Bayesian vector autoregresson results indicate that this program needs some modification for monthly data.
Do forecasts produced by organizations reflect anchoring and adjustment?
Authors: Bromiley Philip 
Published: July 2007

AbstractIn attempting to improve forecasting, many facets of the forecasting process may be addressed including techniques, psychological factors, and organizational factors. This research examines whether a robust psychological bias (anchoring and adjustment) can be observed in a set of organizationally‐produced forecasts. Rather than a simple consistent bias, biases were found to vary across organizations and items being forecast. Such bias patterns suggest that organizational factors may be important in determining the biases found in organizationally‐produced forecasts.
Forecasting from fallible data: Correcting prediction bias with stein‐rule least squares
Authors: Stanley T. D. 
Published: July 2007

AbstractIn the presence of fallible data, standard estimation and forecasting techniques are biased and inconsistent. Surprisingly, the magnitude of this bias tends to increase, and not diminish, in time series applications as more observations become available. A solution to this ever‐present problem, Stein‐rule least squares (SRLS), is offered. It corrects for the bias and inconsistency of traditional estimators and provides a means for significantly improving the predictive accuracy of regression‐based forecasting techniques. A Monte Carlo study of the forecasting accuracy of SRLS, compared to its alternatives reveals its practical significance and small sample behaviour.
The use of non‐time series information in sales forecasting: A case study
Authors: Edmundson Bob , Lawrence Michael , O'Connor Marcus 
Published: July 2007

AbstractThe contribution of product and industry knowledge to the accuracy of sales forecasting was investigated by examining the company forecasts of a leading manufacturer and marketer of consumable products. The company forecasts of 18 products produced by a meeting of marketing, sales, and production personnel were compared with those generated by the same company personnel when denied specific product knowledge and with the forecasts of selected judgemental and statistical time series methods. Results indicated that product knowledge contributed significantly to forecast accuracy and that the forecast accuracy of company personnel who possessed industry forecasting knowledge (but not product knowledge) was not significantly different from the time series based methods. Furthermore, the company forecasts were more accurate than averages of the judgemental and statistical time series forecasts. These results point to the importance of specific product information to forecast accuracy and accordingly call into question the continuing strong emphasis on improving extrapolation techniques without consideration of the inclusion of non‐time series knowledge.
A simple check of the time homogeneity of Markov chains
Authors: Mattsson Anders , Thorburn Daniel 
Published: July 2007

AbstractIn this paper we consider a population where the state of each individual follows a Markov chain. If the population is recorded for a very few periods only, it is still possible to estimate the transition matrix and to make projections into the far future. These forecasts are sensible if the chains are time homogeneous, but this is difficult to check if only a few periods are observed. We suggest a simple method to check this assumption, and obtain an upper bound on the time the process can have been time homogeneous. The method is also applied to a second‐order Markov chain and to the mover‐stayer model.AMS subject classification (1980): Primary 62M05, Secondary 62M20.
Forecasting non‐seasonal time series with missing observations
Authors: Aldrin Magne , Damsleth Eivind 
Published: July 2007

AbstractMost forecasting methods are based on equally spaced data. In the case of missing observations the methods have to be modified. We have considered three smoothing methods: namely, simple exponential smoothing; double exponential smoothing; and Holt's method. We present a new, unified approach to handle missing data within the smoothing methods. This approach is compared with previously suggested modifications. The comparison is done on 12 real, non‐seasonal time series, and shows that the smoothing methods, properly modified, usually perform well if the time series have a moderate number of missing observations.
Optimal conditional ARIMA forecasts
Authors: Guerrero Víctor M. 
Published: July 2007

AbstractAn optimal univariate forecast, based on historical and additional information about the future, is obtained in this paper. Its statistical properties, as well as some inferential procedures derived from it, are indicated. Two main situations are considered explicitly: (1) when the additional information imposes a constraint to be fulfilled exactly by the forecasts and (2) when the information is only a conjecture about the future values of the series or a forecast from an alternative model. Theoretical and empirical illustrations are provided, and a unification of the existing methods is also attempted.
Subjective versus objective combining of forecasts: An experiment
Authors: Flores Benito E. , White Edna M. 
Published: July 2007

AbstractThe paper reports results of an experiment conducted to evaluate subjective versus objective combination of forecasts. The subjects were undergraduate students at Texas A&M. The students forecasted two different types of time series. The results found show that the subjective combination of forecasts improves their accuracy as compared with individual efforts. Four ex‐ante weighting methods were also used to combine the forecasts. They all improve the accuracy of the forecasts. The best results, though, were from the subjective combination of forecasts.