bluuebunny/crossref_metadata_2025 huggingface dataset:
ESCA‐Untersuchungen an anodisch oxydierten AIIIBV‐Verbindungen
Authors: Bilz H. J. , Leonhardt G. , Kühn G. , Löschke K. , Meisel A.
Published: July 2007

Durch schrittweises Abtragen von anodisch erzeugten Oxidfilmen auf GaP, GaAs, GaSb und InSb durch Ar+‐Ionenbeschuß wurden Tiefenprofile erhalten. In allen Fällen wurde festgestellt, daß die Übergangszone zwischen Halbleiter und Oxid mehrere hundert Ångström beträgt. Ebenso wurden die Bindungsenergien der Komponenten bestimmt. Im Gegensatz zu den thermisch oxydierten Proben sind im Film nur oxydierte AIII und BV‐Komponenten nachgewiesen worden.
Untersuchungen zur Wachstumskinetik von Oxidschichten auf polykristallinem Wismut mit Hilfe der Röntgenphotoelektronenspektroskopie
Authors: Wagner N. , Brümmer O.
Published: July 2007

Photoelektronenspektroskopische Untersuchungen ergeben, daß auf einer polykristallinen Wismut‐Oberfläche ein dickenbegrenztes inhomogenes Schichtenwachstum einer Sauerstoffschicht erfolgt. Das Material wurde unter definierten Bedingungen im Labor ausgelagert. Die Wachstumskinetik wird durch einen Mehrstufenprozeß bestimmt, hervorgerufen durch lokale Unterschiede im Kontaktpotential zwischen Metall und Metalloxid. Die Unterschiede entstehen durch eine inhomogene Verteilung von Leerstellen im Kationengitter des Bi2O3. Diesen Schlußfolgerungen liegen in den Anlaufbereichen des Schichtenwachstums der Mott‐Cabrera‐Mechanismus, in den „Sättigungs”︁ bereichen ein logarithmisches Wachstumsgesetz zugrunde. Die Modelle gestatten eine gute Beschreibung der experimentell bestimmten Wachstumsparameter.
Preparation and some properties of thallium orthothioarsenate single crystals
Authors: Olexeyuk I. D. , Babidorich P. I. , Rez I. S. , Voroshilov Yu. V.
Published: July 2007

Growing of large (Ø 25–30 mm, L = 50–60 mm) optically homogenous single crystals of Tl3AsS4 using the Bridgman‐Stockbarger method is described. Tl3AsS4 is orthorhombic (Pnma), a = 8.85 ± 0.03, b = 10.86 ± 0.03, c = 9.18 ± 0.03 Å; z = 4; ϱx = 6.15 g · cm−3; ϱp = 6.15 ± 0,03 g · cm−3, Tm = 424 ± 3°C, Moh's hardness = 3, microhardness and ultrasonics velocity along x, y, z are 65–85 kg · mm−2 and 2.16 – 2.37 · 105 cm · sec−1, respectively. The crystals possess perfect cleavage plane (010). Their transparency range is 0.6–12 microns. – Unsuccessful attempts to obtain Tl3AsS4 and its alloys in the vitreous state were taken. The possibilities of glass formation and boundaries of the vitreous region in the system Tl–As–S based on the characteristic features of the melt forming structural units are analyzed.
Sulphosalt minerals: Crystal chemistry and morphology
Authors: Kostov I.
Published: July 2007

Polymerization of semi‐metallic R2S3 and metallic (M2+M2+)S structural units leads to step‐like change of chemical composition of the sulphosalts and to morphology which is pronouncedly planar for the sulpharsenides, pseudoisometric for the sulphantimonides, and axial for the sulphobismuthides. Isomorphous substitution is very restricted both for semi‐metals and metals.
Zum Sprödverhalten von Muskovit
Authors: Becherer G. , Sitarek U.
Published: July 2007

Auf der Basis der linearen anisotropen Elastizitätstheorie wurden Energiefaktoren K und Energieparameter Kb von möglichen Versetzungen in Muskoviteinkristallen analytisch berechnet. Dabei wird Muskovit entsprechend den elastischen Konstanten als hexagonaler Kristall angesehen. Mit den Energieparameterwerten der angenommenen Gleitsysteme wird das Sprödverhalten des Muskovits erklärt.
Regelungsvorgänge beim Verdichten von Sylvin‐Pulver in Glattwalzenwerken
Authors: Nguyen M. M. , Siemes H.
Published: July 2007

Sylvinpulver wird in Glattwalzenwerken zu plattigen Körpern zu sog. Schülpen verarbeitet. Bei diesem Vorgang werden die Sylvinkörner zusammengepreßt und verformt bis der Porenraum nahezu verschwunden ist. Die zunächst würfelförmigen Körner werden durch die Verformung ± linsenförmig und nehmen Vorzugsorientierungen an. In den oberflächennahen Schichten der Schülpen bildet sich unter dem Einfluß einer Scherverformung eine Vorzugslage mit {111} parallel zur Scherebene (= Walzebene) und 〈011〉 + 〈112〉 parallel zur Scherrichtung (= Walzrichtung) und eine zweite mit {100} parallel zur Scherebene und nur 〈011〉 parallel zur Scherrichtung aus. In den inneren Schichten stellt sich eine achsialsymmetrische Regelung mit {100} senkrecht zur Walzebenennormalen ein.
Röntgenographische Untersuchungen zum Abbau von bleihaltigen Stabilisatoren im PVC
Authors: Martius G. , Brand P.
Published: July 2007

Röntgenographische Untersuchungsmethoden können nicht nur zur Charakterisierung technischer kristalliner Zusatzstoffe für Plaste herangezogen werden. Im Falle der Stabilisatoren zweibasisches Bleistearat und dreibasisches Bleisulfat im PVC wird gezeigt, daß man den Abbau dieser Stoffe bei thermischer Beanspruchung des Materials durch Anfertigung von Diffraktogrammen erfassen kann, wobei basische Bleioxichloride als kristalline Zwischenstufen erkennbar werden. Als Endprodukt der Reaktion der Bleistabilisatoren mit dem bei der Spaltung des PVC freigesetzten HCl entsteht Bleichlorid, wobei auch die Umsetzung des Sulfatanteils des dreibasischen Bleisulfats in dieser Verbindung in Betracht gezogen werden muß. Die Intensitäten der Interferenzen des dreibasischen Bleisulfats und des Bleichlorids auf den Röntgendiffraktogrammen gestatten den Abbauzustand des Werkstoffes nach einem mit einer thermischen Beanspruchung verbundenen Verarbeitungsprozeß einzuschätzen. Es besteht auch die Möglichkeit, die thermische Stabilität verschiedener bleistabilisierter PVC‐Materialien miteinander zu vergleichen.
Tempern von Cd0,2Hg0,8Te im Quecksilberdampf
Authors: Dittmar G. , Forbrig B. , Schubert F.
Published: July 2007

Als Ausgangsmaterial für hochempfindliche Infrarot‐Fotowiderstände wird n‐leitendes Cd0,2Hg0,8Te mit minimaler Ladungsträgerkonzentration und maximaler Ladungsträgerbeweglichkeit benötigt. Durch Tempern im gesättigten Quecksilberdampf kann die Zahl der Defekte, die bei der Kristallzüchtung im Cd0,2Hg0,8Te entstanden sind wesentlich verringert werden. Es werden Einzelheiten der Vorbereitung und Durchführung der Temperversuche sowie experimentelle Ergebnisse beschrieben.
X‐ray and neutron interferometry
Authors: Treimer W.
Published: July 2007

The present state of especially neutron interferometry is presented. Experiments and comparisons with X‐rays shall point out the fields of applications of X‐ray resp. neutron interferometry. The supplementary advantages of these interferometers allow a large number of measurements.
Review of the X‐ray diffraction in extreme asymmetric cases
Authors: Härtwig J.
Published: July 2007

The differences in the theoretical treatment of extremely asymmetric cases in comparison with the conventional dynamical theory of X‐ray diffraction for the perfect crystal are shown and based. Some theoretical results for the four extremely asymmetric cases are presented and discussed. The limit of the conventional theory and the applicability of some of its results in the case of extreme asymmetry are stated.
Quantum mechanical relations in interface processes at electrode systems of the second kind
Authors: Winzer A.
Published: July 2007

It is shown that the difference of the electrochemical standard potentials between Ag/AgCl(s), KCl (aq, a = 1 mole l−1) and Ag/AgBr(s), KBr (aq, a = 1 mole l−1 can be attributed to the ion exchange from the AgCl phase to the AgBr phase. In this process, quantum mechanical relations play an essential part. A relation derived from Einstein's equation for calculating the inner energy of an ionic crystal and from the AC‐Josephson equation allows the calculation of the difference of the electrochemical standard potentials between the electrode systems Ag/AgCl(s), Cl−‐Ag/AgBr(s), Br−; Cu/CuCl(s), Cl−‐Cu/CuBr(s), Br− and Hg/Hg2Cl2(s), Cl−‐Hg/Hg2Br2(s), Br− from the frequency of the longitudinal optical phonons. An equation for the quantum mechanical calculation of the nernst factor (RT/zF) in the so‐called Nernst equation is given. Thus, the structural parameters of the respective solid state electrodes are in close relation with the transport processes in electrode systems of the second kind.
Orientational order of dissolved molecules in the nematic, smectic A and smectic B phases of 4‐n‐hexyloxybenzylidene‐4′‐n‐hexylaniline
Authors: Pelzl G. , Vetters D. , Demus D.
Published: July 2007

The orientational order S of a dichroic dye dissolved in a liquid crystal has been determined in the nematic, smectic A and smectic B phase of 4‐n‐hexyloxybenzylidene‐4′‐n‐hexylaniline. The used method is based on the absorption measurement of unpolarized light in a homeotropic oriented liquid crystalline layer and in an isotropic layer. The orientational order of the dissolved molecules was compared with the order parameter of the liquid crystalline solvent.
Indentation deformation of magnesium orthosilicate single crystals
Authors: Desai C. C. , John V.
Published: July 2007

The variation in the microhardness of the magnesium orthosilicate crystals has been determined using Vicker's microhardness indentor. The length of the rays of dislocation rosettes around the indentation, obtained by etching the indented cleavages have been measured. It is observed that: (i) irrespective of the relative orientation of the indentor and the crystal, the median vents initiated at the sharp indentation edges, (ii) the microhardness of the crystals depends on the applied load, and (iii) the microhardness of the crystal is independent on the duration of loading. The implications are discussed.
Jump‐like twin boundary movement in indium crystals
Authors: Fomenko L. S.
Published: July 2007

This is an investigation of the specific features of twin boundary movement by creep in indium crystals at room temperature. It has been shown that in the most structurally perfect crystals, broadening of twin layers is jump‐like. Jumps in the kinetic relations for boundary displacement are the most pronounced in the stress range where the initial boundary velocity becomes as high as (5 × 10−5–10−4) cm/s. The effect of the applied stress on the average jump density and the characteristic boundary motion velocities, that is the initial velocity, the velocities at the jump and just before it were investigated. Dislocation structure deterioration as well as impurity increase lead to changes in the boundary motion character, namely to monotonic reduction of boundary velocities with time. It has been ascertained that the jump‐like nature of the boundary motion is due to boundary interaction with obstacles present in the crystal and unambiguously associated with periodically changing boundary structure: defect formation and eventual defect inclusion into the twinned material.
Transport Coefficients and Structural Principles of PbOGa2O3 Melt
Authors: Fischer K. , Linzen D. , Sinn E. , Stieff H. , Voigt F.
Published: July 2007

More Precise knowledge of the growth mechanism of garnets in form of epitaxial layers or single crystals in high temperature solutions on the base of trivalent oxides Me2O3 in PbOB2O3 solvent is desirable. Data of physicochemical properties of the melts especially density, shear viscosity, and electrical conductivity and their dependence on the temperature are useful in endeavour to recognize the structural principles of oxidie melts. Therefore as a first step the binary system PbOGa2O3 was investigated to understand the influence of the Ga component on a complete mixed garnet solution, for instance (Y, Sm)3 (Fe, Ga)5O12 in PbOB2O3 solvent.
The Distribution of Thorium in Fluorite Single Crystals
Authors: Nistor L. C. , Nistor S. V. , Teodorescu V. , Voicu I.
Published: July 2007

Single crystals of CaF2 doped with ThO2 were grown by the Czochralski‐Kyropoulos technique in graphite crucibles. The distribution of thorium in the as grown crystals has been investigated by optical and transmission electron microscopy, selected area diffraction and optical spectroscopy.
α‐substitued phosphoryl compounds (IV). The crystal and molecular structure of diethyl[bis‐(p‐chlorophenoxy)‐methan]‐phosphonate, C17H19O5PCl2
Authors: Kulpe S. , Seidel I.
Published: July 2007

Diethyl‐[bis‐(p‐chlorophenoxy)‐methan]‐phosphonate crystallizes in the triclinic space group P 1 with two molecules per unit cell. The lattice parameters are a = 8.757 Å, b = 10.479 Å, c = 12.878 Å, α = 82.21°, β = 116.27°, γ = 113.80°. With X‐ray diffraction data, collected on an automatic four circle diffractometer, the crystal structure was solved by direct methods and refined to an R‐value of 0.049 for 3116 measured and symmetrically independent reflections. The substance is a derivative of acetales of formyl phosphonic acid esters. Correlations between the geometry of the structure and NMR‐data are of interest.
Influence of the revolution number of the stirrer in viscous liquid on the crystal mass growth rate
Authors: Malczewski J.
Published: July 2007

The relative velocity between crystal and viscous solution has significant influence on the crystal mass growth rate. In this article a horizontal crystallizer with a stirrer is considered. It appears that in the case of laminar flow of viscous liquid, the relative velocity between crystal and solution doesn't depend on the revolution number of the stirrer and is approximately equal to the settling velocity of the crystal.
Growth and electrical properties of liquid phase epitaxial layers of GaxIn1‐xP lattice‐matched to GaAs substrates
Authors: Penndorf J. , Kühn G. , Neumann H. , Müller A.
Published: July 2007

From the measurement of the evaporation rate of phosphorus the favourable conditions for the layer growth were determined. Further, we have studied the influence of zinc and silicon on the growth and the morphology. The mobilities, the electron and hole concentrations in the temperature range from 77 to 300 K are presented. In the Si‐doped samples we could not find a correlation between the silicon concentration in the melt and the donor concentrations in the layer. An estimation of the acceptor ionization energy in Zn‐doped samples yields EA = (15 ± 4) meV.
Etching studies of tungstenite (WS2) crystals in acids
Authors: Agarwal M. K. , Reddy K. Nagi
Published: July 2007

Single crystals of tungstenite (WS2) have been grown by direct vapour transport or sublimation method. An etchant capable of revealing the sites of dislocations has been developed. The effects of etching time, etchant concentration and temperature on the selective etch rate have been worked out. It is seen that the etch rate is independent on time, but is influenced by the temperature and concentration of the etchant. The values of activation energy determined from the etch rate against temperature plots established that the process of etching in chromic acid is chemical reaction rate controlled. The effect of addition of HF to the above etchant has led to some further interesting results.
New experimental results on nucleation of Au on NaCl: Dependence on deposition rate and time
Authors: Stenzel H. , Velfe H. D. , Krohn M.
Published: July 2007

Systematic experiments have shown that saturation density, nucleation rate, and condensation coefficient are considerably smaller than previously reported. The low condensation coefficient and the linear deposition rate dependence of the nucleation rate show that the model usually applied for the theoretical explanation of the nucleation process needs some revision. From measured condensation coefficients we have estimated the diffusion length of adatoms, xs = (14.4 ± 2.4) nm, and the difference between desorption and diffusion energy, Ea – Esd = (0.31 ± 0.01) eV. Possible reasons for the deviation of the new results from the earlier ones are discussed.
Growth of CaMoO4 and SrMoO4 crystals in silica gel media
Authors: Kurien K. V. , Ittyachen M. A.
Published: July 2007

Growth kinetics and characterization of calcium and strontium molybdate crystals grown in silica gel have been studied under a variety of parameters. The changes in nucleation characteristics, growth habit, quality of these crystals were carefully observed and are found directly related to pH of the medium. The profound influence of pH on spontaneous crystallization of CaMoO4 crystals has been carefully investigated; and its crystallization range has been determined. The wide morphological change of SrMoO4 with respect to pH variation has been studied. The quality of the crystals has been critically examined.
The influence of the dislocation density on the sulphur segregation at the Ni(110) surface in the course of heating
Authors: Storbeck F. , Heyn T. , Auleytner J. , Jasiolek G.
Published: July 2007

The segregation of sulphur of the surface from Ni(110) monocrystals has been studied by LEED and AES. We have founded that the diffusion is dependent to the temperature and the dislocation density and we interpret this observation with the diffusion along the dislocations and the volume diffusion.
Information gain from analytical description of isothermal resistivity curves
Authors: Oettel W. , Radomsky C. , Löffler H.
Published: July 2007

The experimentally gained course of the resistivity of some Al‐Zn‐Mg alloys during isothermal aging is analyzed by means of a calculation of the extra resistivity of GUINIER‐PRESTON zones based on the solution of the BOLTZMANN‐equation in the isotropic relaxation time approximation and using XSAS intensities quoted by GUINIER and FOURNET.

Applying this equation from the increase of the resistivity information on the time development of the volume fraction of the zones and from the course of the resistivity behind the maximum the growth law of the precipitates can be drawn from the alloys investigated.
XPS investigations of Ti‐supported Pt‐Ir catalytic systems
Authors: Wagner N. , Brümmer O.
Published: July 2007

Some XPS‐spectra (core levels and valence bands) of Ti supported active layers (Pt0.7Ir0.3) on various catalytic activity were investigated. Not only the mentioned species were studied but also the impurity elements oxygen and carbon. All data given below are dependent on the information depth (maximum ∼ 13 nm). The various reactivity can be described quantitatively as well as qualitatively by XPS data. Concerning this the relative change of composition in the surface region is very important.
Growth of single crystals of NaCl in Gels
Authors: Desai C. C. , Rai J. L.
Published: July 2007

The growth of transparent single crystals of sodium chloride (NaCl) in agar and silica gels up to 4 × 4 × 4 mm size is reported. A brief description of the material preparation, growth procedure and crystal nucleation is given. Hydrochloric acid was used to crystallize NaCl incorporated in the gel which reduces the solubility of NaCl in the gel media. Crystalline perfection has been studied using the chemical etching method.
Influence of impurity and indentation time on dislocation rosettes
Authors: Boyarskaya Yu. S. , Kats M. S. , Zhitaru R. P. , Linte M. A.
Published: July 2007

It has been shown that the impurity type and indentation time affect appreciable on dislocation rosettes of NaCl single crystals. It was established that the growth of indentation diagonal was not practically followed by the increase of the dislocation zone size. This phenomenon connected with the cross slip processes, which are perhaps more intensive for prolonged indentation time and high temperatures. The assumption is made that the two mechanisms of responsible for indentation formation the movement of dislocations and their multiplication by the cross slip.
The growth kinetics of barium sulphate crystals in suspension: Scale prevention (I)
Authors: van Rosmalen G. M. , van der Leeden M. C. , Gouman J.
Published: July 2007

The growth process of barium of sulfate crystals suspended in a supersaturated solution has been studied conductometrically. The mean linear rate R̄ has been plotted as a function of the growth affinity — Δμ/RT. A first attempt has been made to fit the experimental growth data in the highest supersaturation range with surface nucleation models.
The precipitation of lead sulphate from aqueous and aqueous alcohol solutions: Nucleation, final sizes and morphology
Authors: Packter A. , Alleem A.
Published: July 2007

The precipitation of lead sulphate was studied from 0.0001 to 0.01 M aqueous solutions (supersaturations 3 to 600) and from 20% aqueous ethanediol, methanol and ethanol solutions, in polypropylene beakers, at ambient temperature: the experimental techniques were conductivity measurements and optical microscopy. The precipitations were heterogeneously nucleated at low supersaturations and homogeneously nucleated at intermediate to high supersaturations. New crystal morphologies generally developed at some what higher supersaturations in the aqueous alcohol systems. The final crystal lengths at first increased with increasing initial metal salt concentration and then decreased with this parameter; the largest crystals at any concentration were obtained from solutions in which lead sulphate solubility was highest. The critical supersaturations (for the onset of homogeneous nucleation) increased from 36 (in water) to 50 (in 20% aqueous ethanol): the surface energies for the formation of nuclei correspondingly increased from 90 to 110 mJ m−2 in good agreement with the Nielsen‐Söhnel relation. The nucleation and crystal growth processes are taking in an aqueous environment of similar water activity to that of the bulk solutions.
X‐ray trajectories in crystals with x‐depending deformation gradients
Authors: Dietrich B. , Härtwig J.
Published: July 2007

Based on the Eikonal theory analytical solutions of the trajectory‐equation were calculated for some special x‐depending deformation gradients, where x shows in the direction of the diffraction vector. For the discussion deformation gradients are chosen which are similar to those in crystals with varying concentrations of impurity atoms. The calculated trajectories allow to obtain properties of section‐ and traverse‐topographs.
Connection between electrical and deformation characteristics of PbS crystals
Authors: Milevskii L. S. , Tkacheva T. M. , Urusovskaya A. A. , Knab G. G.
Published: July 2007

The influence of plastic deformation on temperature dependence of carrier concentration n and mobility μ in PbS crystals has been studied. Comparison of the results obtained with selective etching patterns from original and deformed crystals makes it possible to conclude that during the plastic deformation there takes place a dissolution of precipitates by passing of dislocations through them. As a results, rows of point defects appear along the path of dislocation movement which may be the cause of a change in n and μ due to deformation. A change in the electron scattering mechanism below 110 K has been discovered.
Influence of plastic deformation on the photoconductivity of CdTe
Authors: Zozime A. , Schröter W.
Published: July 2007

Investigation of photoconductivity have been performed on p‐type phosphorus doped CdTe (5 × 1015 cm−3) deformed by compression at room temperature. Using a technique of axial illumination, the contribution of the surface to the photoconductivity is suppressed. In the investigated energy range (0.08–1.54 eV), and at room temperature, a maximum of the signal of the non‐deformed material is of found at 1.312 ± 0.009 eV, with a half width of 0.100 eV, whereas the 0.3% deformed material presents a maximum at 1.348 ± 0.009 eV with the same half width. At 223 K these peaks are shifted to higher energies, the half width remaining unchanged, and the amplitudes being ∼ 30 times higher.
Dislocation energy levels in deformed silicon
Authors: Patel J. R. , Kimerling L. C.
Published: July 2007

Abstract‐Energy levels in deformed silicon have been directly measured by transient junction capacitance techniques. If complex slip band formation is not suppressed, a large variety of states are observed after deformation with a prominent state at Ev − 0.68 ev. After annealing at 900°C the complex defect spectra simplify to two dominant states at Ev + 0.35 ev and Ec − 0.38 ev. In more homogeneously deformed silicon where slip band formation is suppressed, the dominant state at Ec − 0.68 ev is not observed after deformation and the spectra resembles that obtained after annealing the complex spectra at 900°C.
Investigation of structural defects in polycrystalline silicon by electron microscopy
Authors: Gorelik S. S. , Zarifyants Z. A. , Milevskii L. S. , Sagalova T. B.
Published: July 2007

Thermostability of polycrystalline films and their structure changes have been investigated in dependence on the fast electron irradiation. It was shown that the type of the radiation defects depends on the irradiation. temperature. The temperature of the recrystallization process is shown to decrease from 1300°C in the case without irradiation down to 1000°C in the case of recrystallization when irradiating.
Differential thermal analysis studies on the crystallization of strontium tungstate melts. Variation of rate constants with crystallization temperatures and cooling rates
Authors: Roy B. N. , Appalasami S. , Chatterji A. K.
Published: July 2007

Kinetics of strontium tungstate crystallization from sodium tungstate melts were studied in platinum crucibles (by DTA) by continuous cooling from initial crystallization temperatures T0 = 800° to 1000° to below the eutectic temperature at cooling rates RT = 0.67° to 3.3° min−1. Heterogeneous nuclei first formed slowly onto metal platinate particles within the solution during induction periods (t); the main crystal growth then started after the development of some exces solute concentration (ΔC) at the induction temperature (T). The actual growth after t was diffusion rate‐controlled. The diffusion rate‐constants (kDt) for growth after the induction periods along the major axis were estimated; the increased with T0 and RT. These values were higher than those for diffusion‐controlled crystal growth of strontium tungstate from sodium tungstate melts in alumina crucibles but much smaller than the real diffusion rate‐constants (kDl)real.
On the decomposition behaviour of supersaturated Al‐Zn‐Mg alloys in dependence on heat treatment
Authors: Löffler H. , Korngiebel E. , Gerlach R.
Published: July 2007

The influence of the various heat treatments applied on the decomposition processes taking place in some Al‐Zn‐Mg alloys (varying in Zn as well as Mg content) are discussed based on the main assumptions that 1) the upper limit of the temperatur of homogeneous nucleation, Thn, plays an important role on the kind of nucleation taking place at the aging temperature, Ta, and 2) vacancy‐rich clusters, VRC, as well as overcritical GP zones can act as nucleation sites for η′;‐particles at Ta > Thn. The influence of the VRC is decreasing with rise of the Zn‐content.
Effect of oxygen in silicon on pn‐junction characteristics
Authors: Geyer L. , Heymann G.
Published: July 2007

In this paper the influence of oxygen on the characteristic of planar diodes was studied for p‐type dislocation free Czochralski silicon. Particular attention was paid to the formation of thermodonors in heat treatment at 450°C and of oxygen‐silicon precipitations, and the defects ensuing from them in heat treatments above 600°C. It was shown that there exists a connection between component properties and oxygen concentration.
Preferred growth of bismuth single crystals
Authors: Shah B. S.
Published: July 2007

The results of the study of the factors influencing the orientation of the (111) cleavage plane of bismuth are presented. It has been observed that at high purity the growth rates and temperature gradients do influence the orientation whereas at low purities no such influence is observed.
Intensities of overlapping peaks in X‐ray powder diffraction
Authors: Valvoda V. , Voland U.
Published: July 2007

Separation of overlapping peaks in X‐ray powder diffraction is investigated by means of fitting a modified Lorentzian function to experimental profiles of reflexions. Application of the new type of analytical function and simultaneous refinement of background level parameters are described and discussed with respect to the accurate determination of integrated intensities of reflexions.
The calculation of critical size of carbon clusters in ferrite
Authors: Schmidt R. , Berg G , Fröhlich F.
Published: July 2007

The formation of carbon clusters in ferrite is investigated by the simulation of random motion of carbon particles in a cubic primitive model lattice at different annealing temperatures. All computer runs are repeated to average the results. An interaction potential is assumed between the particles precipitated in the formed cluster and the particles in the matrix. Additionally a decay of the cluster is allowed. A cluster of critical size is formed if the probability of decay is lower than the precipitation rate. The critical size calculated depends on the annealing temperature as the results show unambigously.
New thermotropic cubic mesophases
Authors: Demus D. , Gloza A. , Hartung H. , Hauser A. , Rapthel I. , Wiegeleben A.
Published: July 2007

1,2‐Bis‐[4‐n‐alkyloxybenzoyl]‐hydrazines with the general formula magnified image possess smectic C phases and at lower temperatures additional optically isotropic phases. According to X‐ray investigations these isotropic phases show cubic symmetry. The lattice units consist of aggregations with micellar dimensions. The substances were characterized by microscopic, dilatometric and calorimetric investigations. The new cubic mesophases do not exhibit complete miscibility with the “smectic D” phases.
Decision trees for forecasting
Authors: Ulvila Jacob W.
Published: July 2007

Recent years have seen an increasing cross‐fertilization between the fields of decision analysis and forecasting. Decision‐analytic models often require forecasts as inputs, and aspects of the Bayesian decision‐theoretic framework underlying decision analysis have proved useful to forecasting, particularly in contexts where subjective judgemental inputs are required. This paper describes the use of decision tree analysis for forecasting and illustrates its use for corporate divisional forecasting and planning. A specialized decision‐analytic technique, acts as events, is also described and illustrated to forecast a new product's earnings. Conclusions are drawn about the applicability of decision analysis for forecasting.
Note the use of growth curves in forecasting market development
Authors: McGowan Ian
Published: July 2007

In this note the four‐parameter generalized logistic curve is introduced and some of its properties are discussed. The curve is then fitted to certain data sets. The results indicate that the generalized logistic can be a worthwhile alternative to the more familiar logistic and Gompertz curves.
Linear combination of forecasts with an intercept: A bayesian approach
Authors: Bordley Robert F.
Published: July 2007

The standard approach to combining n expert forecasts involves taking a weighted average. Granger and Ramanathan proposed introducing an intercept term and unnormalized weights. This paper deduces their proposal from Bayesian principles. We find that their formula is equivalent to taking a weighted average of the n expert forecasts plus the decision‐maker's prior forecast.
Technological forecasting with nonlinear models
Authors: Lee Jack C. , Lu Kevin W. , Horng S. Crystal
Published: July 2007

The S‐shaped growth curves such as Gompertz, logistic, normal and Weibuli are widely used for forecasting technological substitutions. A family of data‐based transformed (DBT) models, which are linear in the regression parameters, including the above‐mentioned four models as special cases has been shown to be quite useful for short‐term forecasts. This paper explores modeling the technology penetration data directly with assumed S‐shaped growth curves. The resulting models, which are nonlinear in the regression parameters, also incorporate proper dependence structure and power transformation. It appears that the nonlinear modeling is a viable alternative to the DBT and other conventional forecasting models in forecasting technological substitutions. Hence, an appropriate strategy is to consider the nonlinear modeling approaches as possible alternatives and use the data at hand to select, via pseudo‐cross‐validation, the best model for forecasting purposes.
A predicting system based on combining an adaptive predictor and a knowledge base as applied to a blast furnace
Authors: Jian Chen
Published: July 2007

In this paper a system is proposed and applied to predicting silicon content in pig iron for a blast furnace. It combines an adaptive predictor with a knowledge base. On‐line experiments show that the prediction accuracy of the system is much better than that of an experienced operator or of an adaptive predictor alone. Such a system will be helpful to operators in selecting desirable control methods.
Thinking about the future: A cognitive perspective
Authors: Klayman Joshua , Schoemaker Paul J. H.
Published: July 2007

The promises and challenges of a cognitive approach to strategic planning and subjective forecasting are examined. Strategic thinking is viewed as comprising three components: (1) knowledge base, (2) problem representation, and (3) inference processes linking the first two. Analysis of these components, it is argued, can be an important aid to understanding and guiding managerial problem solving. We review several techniques for modeling strategic thinking and planning, including network representations, production systems, causal maps, and analyses of argumentation. We consider the strengths and weaknesses of different cognitive analysis techniques and discuss how they might be implemented. Much more experience and refinement will be needed to produce well‐specified procedures for cognitive analysis of planning. We conclude, however, that even at the current stage of development, significant benefits can accrue from a cognitive approach to strategic planning.
Business survey data in forecasting the output of swedish and finnish metal and engineering industries: A kalman filter approach
Authors: Rahiala Markku , Teräsvirta Timo
Published: July 2007

In this paper forecasting the production volume of the Swedish and Finnish metal and engineering industries one quarter ahead is discussed. A practical way of making use of the predictive information in the answers of the quarterly business survey is presented which is based on the application of the Kalman filter. It is found that the most informative questions of the business survey from the point of view of forecasting are different in the two countries. However, for both Sweden and Finland, the improvement in prediction accuracy after taking account of relevant business survey information is significant when the precision of autoprojective forecasts is used as a baseline.
Forecasting quarterly data using monthly information
Authors: Rathjens Peter , Robins Russell P.
Published: July 2007

There are occasions when researchers are interested in quarterly forecasts of variables that are released at higher frequencies. In these situations it is common for researchers to convert from the higher frequency to the lower frequency by some method, such as averaging or stock‐end, and then to model the low‐frequency data. This paper shows how to improve quarterly forecasts by using within‐quarter variations of monthly data. We compare the one‐step‐ahead and multi‐step‐ahead forecasts for real GNP generated using our approach with those of Fair and Shiller (1990). Our model is extremely simple and, yet, or perhaps because of, produces a lower RMSE than any model in Fair and Shiller (1990).
Assessing inefficiency in the s&p 500 futures market
Authors: Farrell C. H. , Olszewski E. A.
Published: July 2007

We analyse the price movement of the S&P 500 futures market for violations of the efficient market hypothesis on a short‐term basis. To assess market inefficiency we construct a model and find that the returns, i.e. the difference in the logarithm of closing prices on consecutive days, exhibit the usual conditional heteroscedasticity behaviour typical of long series of financial data. To account for this non‐linear behaviour we scale the returns by a volatility factor which depends on the daily high, low, and closing price. The rescaled series, which may be interpreted as the trend‐countertrend component of the time series, is modelled using Box and Jenkins techniques. The resulting model is an ARMA(1,1). The scale factors are assumed to form a time series and are modelled using a semi‐non‐parametric method which avoids the restrictive assumptions of most ARCH or GARCH models. Using the combined model we perform 1000 simulations of market data, each simulation comprising 250 days (approximately one year). We then formulate a naive trading strategy which is based on the ratio of the one‐day‐ahead expected return to its one‐day‐ahead expected conditional standard deviation. The trading strategy has four adjustable parameters which are set to maximize profits for the simulation data. Next, we apply the trading strategy to one year of recent out‐of‐sample data. Our conclusion is that the S&P 500 futures market exhibits only slight inefficiencies, but that there exist, in principle, better trading strategies which take account of risk than the benchmark strategy of buy‐and‐hold. We have also constructed a linear model for the return series. Using the linear model, we have simulated returns and determined the optimum values for the adjustable parameters of the trading strategy. In this case, the optimum trading strategy is the same as the benchmark strategy, buy‐and‐hold. Finally, we have compared the profitability of the optimized trading strategy, based on the non‐linear model, to three ad hoc trading strategies using the out‐of‐sample data. The three ad hoc strategies are more profitable than the optimized strategy.
Forecasting marginal costs of a multiple‐output production technology
Authors: Lady George M. , Moody Carlisle E.
Published: July 2007

This paper presents the results of fitting a scaled translog restricted profit function to ‘pseudo’‐data formed by repeated runs of a large linear programming model of domestic and international refining. The translog approximation is designed to estimate the marginal cost of producing eight petroleum products given the amounts of each product demanded and the price of crude oil. We test the model against out‐of‐sample data from the refinery model and historical data. The model is used in the US Department of Energy's Annual Energy Outlook forecasting system.
Forecasting the business cycle without using minimum autocorrelation factors
Authors: Löfgren Karl‐Gustaf , Ranneby Bo , Sjöstedt Sara
Published: July 2007

We introduce a forecasting technique based on multivariate ideas previously applied in remote sensing. The approach has the trivial but nonetheless fundamental purpose of dividing the information inherent in the time series into important and unimportant. Important information is used for forecasting purposes while the unimportant is discarded. Although related to vector autoregression, giving asymptotically the same estimates, there are reasons to believe that the approach gives better precision of parameter estimates for finite samples as well as more precise predictions.
On the limitations of comparing mean square forecast errors
Authors: Clements Michael P. , Hendry David F.
Published: July 2007

Linear models are invariant under non‐singular, scale‐preserving linear transformations, whereas mean square forecast errors (MSFEs) are not. Different rankings may result across models or methods from choosing alternative yet isomorphic representations of a process. One approach can dominate others for comparisons in levels, yet lose to another for differences, to a second for cointegrating vectors and to a third for combinations of variables. The potential for switches in ranking is related to criticisms of the inadequacy of MSFE against encompassing criteria, which are invariant under linear transforms and entail MSFE dominance. An invariant evaluation criterion which avoids misleading outcomes is examined in a Monte Carlo study of forecasting methods.
On the limitations of comparing mean square forecast errors: A reply
Authors: Clements Michael P. , Hendry David F.
Published: July 2007

We are grateful to the twelve discussants for their many insightful and constructive comments on our paper, although we are surprised by both the number of discussants and their near unanimity that the paper was ‘provocative’. We have organized our reply under seven headings, concerned, respectively, with method comparison versus model comparison; the role of the forecast horizon; the choice of loss function; the GFESM measure; the choice of information set; truth versus congruence; and the issue of testing versus comparisons.
Use and misuse of unobserved components in economic forecasting
Authors: Maravall Agustín
Published: July 2007

The paper deals with unobserved components in economic time series within a general model‐based approach. The component, its final estimator, and the preliminary one (which also includes the forecast) are seen to follow different ARIMA models, which can be expressed in terms of the series innovations. Analytical expressions are derived for the different types of associated errors. Two applications are presented. The first shows how the use of unobserved components can increase substantially forecasting precision, and how the model‐based approach can rigorously answer questions of applied concern. The second application illustrates the dangers of using unobserved components in some macroeconomic models. It is first shown how unobserved component estimators, such as a series seasonally adjusted with XII or with a model‐based procedure, will most likely be non‐invertible, and hence invertible models (for example, a VAR model) are not appropriate for them. Second, the recent Stock and Watson model aimed at forecasting recessions is used to illustrate how probabilities computed over the distribution of the component, of its final estimator, and of its preliminary one will be poor estimators of each other. As a consequence, the recession forecasts will be systematically biased.
Are economic forecasts valuable?
Authors: Stekler H. O.
Published: July 2007

A previous study questioned whether the published forecasts of one forecasting organization were valuable to users. A forecast was considered valuable if it differed significantly from a naive model in the sense of predicting the direction of change. The results indicated that it was not possible to show that the one‐quarter‐ahead predictions were valuable. However, the current‐quarter forecasts were valuable. This paper examines whether the results are robust. The forecasts of two additional organizations were examined and the time period was extended. The results are generally robust.
The long run, causality, and forecasting in the advertising‐sales relationship
Authors: Zanias George P.
Published: July 2007

Co‐integration analysis is used in a study of the advertising and sales relationship using the Lydia Pinkham data set. The series are shown to have a valid long‐run relationship while Granger‐causality runs in both directions. The latter is found by using a causality test involving the co‐integration restrictions which seem to constitute a crucial part of such tests in the case of co‐integrated variables. A comparison with previous models shows that forecasting co‐integrated series is more accurate with error‐correction systems, especially in the case of multi‐step forecasting.
A state space approach to forecasting the final vintage of revised data with an application to the index of industrial production
Authors: Patterson K. D.
Published: July 2007

There is considerable interest in the index of industrial production (IIP) as an indicator of the state of the UK's industrial base and, more generally, as a leading economic indicator. However, this index, in common with a number of key macroeconomic time series, is subject to revision as more information becomes available. This raises the problem of forecasting the final vintage of data on IIP. We construct a state space model to solve this problem which incorporates bias adjustments, a model of the measurement error process, and a dynamic model for the final vintage of IIP. Application of the Kalman filter produces an optimal forecast of the final vintage of data.
An accurate calibration method for a range finder based on a 3‐D model of the optical system
Authors: Ueshiba Toshio , Yoshimi Takashi , Oshima Masaki
Published: July 2007

Range finding based on the projected light method is superior as a highly reliable means of obtaining dense three‐dimensional (3‐D) information about scenes. The use of this method, however, demands the development of an accurate calibration method.

This paper proposes a method in which the optical system of the range finder is divided into the region surrounding the video camera and the region surrounding the light sources and rotational mirror, and calibration is by the method of least squares.

The optical system is modeled in three dimensions and includes geometrical parameters not taken into account in earlier methods such as the torsion of the rotational axis of the mirror. Therefore, this method can be used with the camera and the light source located in any positions. In addition, only a calibration board with a reference pattern is used as a jig. Therefore, highly reliable results are obtained easily because no components other than those of the range finder intervene. This calibration method was applied to the multilight‐sources range finder developed by the authors to evaluate its accuracy and to verify its validity.
A segmentation method for composite text/graphics (halftone and continuous tone photographs) documents
Authors: Ohuchi Satoshi , Imao Kaoru , Yamada Wasaku
Published: July 2007

When processing composite documents for digital copy machines and facsimile which contain a mixture of text, halftone and continuous tone photographs, ideally, the text portion can be separated from the graphics portion and more efficiently represented than the multi‐bit pixel bitmap graphics representation. The technique for realizing this necessarily requires very precise image segmentation technology so that both the text and image portions can be correctly separated and efficiently managed. In this paper, a new image segmentation algorithm called SPACE is presented. The main idea behind the method for segmenting text/graphics composite documents is based on a peak‐pixel method for detecting the halftone graphics and edge detection performed on a continuous black and white representation of the image. The results presented here are based on 64‐level gray‐scale, 400 dpi scanned images; but the segmentation method should also be applicable to color images and, as the image quality improves, the method becomes more effective.
Human reader: An advanced man‐machine interface based on human images and speech
Authors: Suenaga Yasuhito , Mase Kenji , Fukumoto Masaaki , Watanabe Yasuhiko
Published: July 2007

There have been many reports of concepts for outstanding interfaces combining language with nonverbal media such as facial expressions and gestures, but few attempts have been made to actually build and test such systems. The authors present a new configuration for a visual and audio media‐based human computer interface named “Human Reader” and report on the realization and experimental verification of a portion of the system. The visual component of the Human Reader configuration consists of a subsystem called Human Image Reader, which detects head movement through a Head Reader and hand movement through a Hand Reader, using multiple workstations. Three video cameras placed to the front, side, and overhead record the face and hand movements of the subject, whose head and hand movements are extracted and analyzed in real‐time. The voice is captured by a microphone from a voice recognition unit, which recognizes spoken commands. The image generation system CG Secretary presents an image with varied expressions on the workstation screen, with synchronized vocal output to create a more natural interface between human and computer. Head Reader enables workstation window switching, while Hand Reader enables the user to control electronic presentations. Both applications were tested with excellent results.