bluuebunny/crossref_metadata_2025_split huggingface dataset:
α‐HgI2 platelets crystallization from vapour
Authors: Laskowski Jaroslav , Przyłuski Jan , Conder Kazimierz 
Published: January 2007

AbstractPreparation of vapour grown platelet shaped α‐HgI2 crystals is discussed. Total pressure, temperature profile and ampoule configuration influence the yield of the process, deposition pattern, crystal shape and morphology. Growth conditions (vapour flow and surface processes) are more important for platelets formation then nucleation on the ampoule's walls. A source temperature of 150–180 °C, total pressure of 2–10 Torr at RT and horizontal configuration of the ampoule create advisable conditions for platelets growth.
Influence of impurity type on microhardness anisotropy of NaCl single crystals
Authors: Boyarskaya Yu. S. , Zhitaru R. P. , Palistrant N. A. , Linte M. A. , Terzi Z. F. 
Published: January 2007

AbstractThe measurements of the microhardness on the (001) and (111) face of pure and doped NaCl crystals in temperature interval 77–750 K have been performed. It is revealed that the value of II kind microhardness anisotropy, established at room temperature, is influenced by the impurity type. The change of microhardness anisotropy sign takes place at a definite temperature. It is a consequence of a different thermostability of the face under investigation.
Growth and spectroscopic characterisation of Neodymium Aluminium Barium Borate using floating zone apparatus
Authors: Kumar J. , Thirumavalavan M. , Gnanam F. D. , Ramasamy P. 
Published: January 2007

AbstractTransparent Neodymium Aluminium Barium Borate (NABB) rods, 60 mm long and 5 mm in diameter, have been grown using a Floating Zone (FZ) apparatus. The preparation of sintered feed rods and growth conditions are presented. The vibrational spectra (IR and Raman) of the rods were compared with those of Neodymium Aluminium Borate (NAB) crystals grown from flux. The spectra confirmed the presence of BO3 network which had been identified to have more advantages when compared to the silicates. The absorption and the fluorescence spectra obtained for the sample demonstrates its efficiency for use as a laser material.
Representation of simulated X‐ray topographs by means of the FEAG 200 device
Authors: Härtwig J. , Witt H.‐J. , Bąk‐Misiuk J. 
Published: January 2007

AbstractThe photoscan and photowrite system FEAG 200 was used to represent computer simulated X‐ray section topographs. Simulated images with a high quality and with film properties similar to the real image could be obtained. Thus, theoretical images could be compared in great detail with experimental topographs.
Thermoelectric power measurements of vacuum‐deposited SnO2/Sb2O3 mixed thin films
Authors: Kumar J. Siva , Subba Rao U. V. 
Published: January 2007

AbstractThin films of various thicknesses have been prepared from the powders of [SnO2 + Sb2O3] sample by the thermal evaporation technique in the vacuum of 10−5 Torr. A jig which is convenient for the measurement of thermoelectric power on thin films in the temperature range from RT to 300 °C is designed and fabricated in our laboratory. Using the jig, thermoelectric power measurements have been made on thin films of [SnO2 + Sb2O3]. These results have shown that these thin films are n‐type in nature. The parameters like thermoactivation energy at 0 °C, temperature coefficient of activation energy, carrier concentration etc. have been calculated. The results thus obtained are presented and discussed in this paper.
A method for determination of size‐dependent crystal growth kinetics from batch experiments (II). Two‐experiment estimation
Authors: Blickle T. , Lakatos B. , Halász S. , Molnár I. 
Published: January 2007

AbstractThe method developed for determining size‐dependent crystal growth kinetics utilizes measurement data obtained in two batch crystallization experiments performed under the same circumstances: (1) size distribution data of the seed and product crystals of a seeded experiment and (2) the equilibrium supersaturation course of an unseeded one. In the latter case, computation is carried out in direction of reversed time thus eliminating the effect of nucleation. The evaluation makes use of the population balance equation transformed by using the assumption that the crystal growth rate is a product of two factors, the first of which depends only on the crystal size whereas the second one on the supersaturation. The application of the method is illustrated by evaluating measurement data of two appropriate experiments with potash alum crystals.
Redetermination of the crystal structure of khellin, 4,9‐dimethoxy‐7‐methyl‐5H‐furo(3,2‐g) (1)‐benzopyran, C14H12O5
Authors: El‐Kordy M. , Farag I. S. Ahmed , Will G. 
Published: January 2007

AbstractThe crystals of this compound are monoclinic with space group P21/n. The unit cell parameters were derived from least squares fit of the angular data for 24 high angle reflections. The lattice parameters are: a = 11.550(2), b = 7.163(1), c = 14.425(2) Å, β = 93.61(1)°, Z = 4.The structure of this compound was solved by direct methods and refined by full matrix least‐squares with anisotropic factors to R = 0.041. The refinement of the atomic parameters reflects the planarity of the molecule in the solid state. The molecules are connected by hydrogen bonds forming a zigzag chain parallel to the [100] direction.
X‐ray diffraction study of TiN coatings sputtered at different substrate temperatures
Authors: Valvoda V. , Kužel R. , Černý R. , Dobiášová L. , Musil J. , Poulek V. 
Published: January 2007

AbstractMicrostructure evolution in TiN films reactively sputtered on steel substrates was investigated by X‐ray diffraction. Systematic changes of lattice parameters, texture, internal strain, and macrostress with increasing nitrogen flow into the magnetron deposition chamber were studied for the samples deposited at two different substrate temperatures (150 and 400 °C), and non‐monotonic dependences were found for all the quantities. A preferred orientation of the 〈111〉 type for substoichiometric samples is changed to the strong 〈110〉 texture at high nitrogen flow. The largest microhardness was observed for the strongly substoichiometric and very defective films. A marked anisotropy of X‐ray line broadening and lattice parameters was found for these samples. The influence of the higher substrate temperature on microstructure of the films is small for all the measured quantities at the deposition rate used (0.06–0.2 μm · min−1).
Influence of chemical composition on structural and selected physical properties of natural natrolites
Authors: Pechar František 
Published: January 2007

AbstractThe relation among changes in contents of Si and Al atoms, molecules of water and symmetry of the unit cell of crystal natural Natrolites was determined.It was found that with the change of the relations Si/Al and Na/H2O the symmetry of the Natrolite structure changes from Fdd2 through Fd(Cc) to F4d2 (I4d2). With the change in the distribution of these atoms in this structural position also changes of optical (refractive index, IR spectra) and thermodynamic (Sconf) properties and thermal stability are closely connected.
Colour bands of oxidized nickel dioximes
Authors: Oza A. T. 
Published: January 2007

AbstractStrong colour bands are observed in the mull absorption spectra of the oxidized nickel chain dioximes bis (1,2‐benzoquinonedioximato) Ni.I0.5 and bis (diphenylglyoximato) NiIIIBr in the long wavelength region of the optical spectrum which are ascribed to the reduced metal‐metal distance due to oxidation. The uv‐visible spectra of bis (dimethylglyoximato) NiII and bis (diphenylglyoximato) NiII have also been studied in the present comparative study. All the bands in the uv‐visible range are assigned. The transitions and the effects of partial oxidation on the electronic transitions are discussed.
Effect of polarity of smectic Ad molecules on the induction of the nematic phase in binary mixtures of smectics A1 and Ad
Authors: Dąbrowski R. , Czupryński K. 
Published: January 2007

AbstractThe phase diagrams are determined of binary mixtures composed of 4‐n‐alkylbiphenylates 4‐cyanobiphenyl (n‐CBB)‐smectics A1, for n < 8 and esters of 4‐(trans‐4′‐n‐alkylcyclohexyl)benzoic acid (10CPCHB, 10NPCHB, 10FOPCHB)‐smectics Ad.The effect is studied of the smectic layer spacing ratio and polarity of the components on the induction of the nematic phase in the tested series of compounds. The virtual NSAd phase transition points in series n‐CBB are estimated and the effect is discussed of the stability of the smectic phase and polarity of the molecules of the mixture components on the width and position of the nematic gap.
Investigations for the improvement of the radial doping homogeneity of dislocation‐free floating zone silicon crystals
Authors: Schröder W. , Rost H.‐J. , Wolf E. 
Published: January 2007

AbstractIn order to improve the doping inhomogeneities of dislocation free FZ Silicon crystals with diameters ≧ 75 mm investigations were carried out to influence the shape and curvature of the crystallization interface during the crucible‐free floating zone crystal growth process. In this works shapes and geometries of the applied melting inductors and the relative positions of these inductors to the seed axis were examined concerning the values of radial macroscopic and microscopic doping inhomogeneities in dependence on other growth parameters, for instance crystal rotation rate. The application of eccentric inductor‐seed positions effects a decreasing “bending value” of the crystallization interface, that means an improvement of the macroscopic radial doping inhomogeneity with crystal rotation rate in the range between 4 and 8 min−1.
Dielectric behaviour of TGS crystals poled by doping on repeated temperature cycling
Authors: Lhotská V. , Holakovský J. , Fousek J. , Březina B. 
Published: January 2007

AbstractData characterizing the stability of basic dielectric properties against thermal treatement are presented for crystals of TGS and deuterated TGS doped with alanine or bivalent platinum. Complex permittivity and over‐all polarization have been measured during a heating‐cooling cycle. In alanine doped crystals the heating and cooling curves are perfectly reproducible. In Pt‐doped samples the reproducibility is worse, for pure TGS the properties on cooling are strongly influenced by domain effects. These data made it possible to estimate the change of the figures of merit for pyroelectric ir detectors due to transient heating.
A systematic search of the dopants of calcium sulphide and their effect on the TL spectra above room temperature
Authors: Rennie J. , Sweet M. A. S. 
Published: January 2007

AbstractResults on the thermoluminescence following incorporation of a wide range of dopant materials in calcium sulphide are reported. These results are compared with those previously reported in the literature. Factors such as fluxes and preparation technique are varied to determine their effect on the TL spectra. Conclusions regarding the possible source of the traps causing the TL in CaS are drawn with the evidence suggesting natural defects as the source of the traps; the added dopant impurities having only a secondary effect on the thermoluminescence peak temperatures.
Optimization of the cascade crystallizers
Authors: Belcu M. , Pincovschi E. 
Published: January 2007

AbstractFor the cascade crystallization process a set of technological optimization conditions was established. The possibility of succesful application of proposed optimization conditions was pointed out by comparison with a mathematical model of Na2SO4 · 10 H2O crystallization in multichamber crystallizer presented in the literature. The method has a general applicability and can be used for the optimization of any cascade‐linked system, provided that the mathematical model was detailed enough to permit the operation of numerical derivation.
Entropy production in steady‐state eutectic growth
Authors: Wolczyński Waldemar 
Published: January 2007

AbstractA theoretical analysis of models for regular eutectic growth is presented. The diffusion model (practically, a relationship between interlamellar spacing, λ, and growth rate, v, proposed in JACKSON and HUNT'S theory) is localized at the paraboloid of entropy production for the process under investigation. As this paraboloid depends on the temperature and concentration gradients it is concluded that a new model which should consider both heat transfer and diffusion in the steady‐state eutectic growth is to be introduced using the substantiated criterion of minimum entropy production. In this way, it is possible to obtain an equation of the f(λ, v, δT/δx) = 0 type.
Influence of the structure of InP thin films on electron energy loss spectra
Authors: Gründler R. , Boudriot H. , Deus K. , Sckneider H. A. , Stöckert T. 
Published: January 2007

AbstractElectron energy loss measurements were carried out on single crystalline, polycrystalline, and amorphous InP thin films. Plasmon data and structures of − Im ε−1 are discussed in dependence on degree of crystallinity.
The influence of γ‐irradiation on ferroelectric and polarization properties of TGS crystals
Authors: Tsedrik M. S. , Margolin L. N. , Gontarev V. F. , Misko A. S. 
Published: January 2007

AbstractThe experimental investigation of pyroelectric and polarization properties of TGS crystals was made. TGS crystals were grown under constant growth conditions (temperature and supersaturation of the solution) and γ‐irradiated in a wide range of irradiation. The influence of γ‐irradiation on the quality parameter M2 of crystals, on the form of hysteresis loops, on size of spontaneous polarization and shifting field was ascertained.
Electrooptic properties of polycrystalline SnSe thin films
Authors: Bhatt V. P. , Gireesan K. , Desai C. F. 
Published: January 2007

AbstractIt is observed from the studies of electrical resistivity of films of SnSe of different thicknesses and substrate temperatures that resistivity decreases with increase in thickness and substrate temperature. The study of variation in band gap with thickness shows a linear relationship between band gap and 1/t2. Finally, band gap – substrate temperature studies show that the band gap increases with substrate temperature.
Infrared optical properties of (CuGe2P3)1−x(6 Ge)x solid solutions
Authors: Riede V. , Sharif N. , Neumann H. , Sobotta H. , Omar M. S. 
Published: January 2007

AbstractInfrared reflectivity spectra of (CuGe2P3)1−x(6 Ge)x mixed crystals with compositions in the range x = 0.07–0.33 are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. An analysis of the spectra reveals six vibrational modes. The composition dependence of the mode frequencies and of the free carrier concentration and mobility is given and compared with infrared optical data for CuGe2P3.
Memory‐switching effect in single crystals of thallium selenide
Authors: Hussein S. A. 
Published: January 2007

AbstractIt has been found that thallium selenide single crystals exhibit bistable or memory switching. The specimen under test showed threshold switching with critical field of the switching being ∼ 103 V/cm at room temperature. Memory switching effect measurements were performed with single crystals of p–TlSe. The results strongly indicated that the phenomenon in our sample is very sensitive to temperature, light intensity and sample thickness. Memory state persists if the current is decreased slowly to its zero value. However, if current was forced to decay suddenly, the specimen returned to the high resistance state. The current‐voltage characteristics is symmetrical with respect to the reverse of the applied voltage and current. The switching parameters were checked under the influence of different factors of the ambient condition. An analysis of the results was done.
Preparation and properties of ultratransparent NaCl single crystals
Authors: Nistor S. V. , Mateescu C. D. , Nistor L. C. , Teodorescu V. S. 
Published: January 2007

AbstractThe preparation of up to 100 mm diameter single crystalline ingots of ultratransparent NaCl by injecting the reactive atmosphere is reported. The resulting material exhibits high optical quality and bulk absorption coefficient at 10.6 μm of 0.91 × 10−3 cm−1, close to the intrinsic value, which makes it suitable for transmissive components in high‐power CO2 lasers.
Rietveld refinement of Y2O3 using the Pearson VII profile shape function
Authors: Smrčok L. 
Published: January 2007

AbstractVery good agreement between the observed and the calculated intensities was obtained using the Pearson VII profile shape function. The variable exponent m could be refined only in the damped iterations involving exclusively the profile parameters. Simultaneous refinement of the m with the positional and/or thermal parameters has led to large oscillations of the shifts of almost all parameters. Precision of the refined atomic coordinates is better than those from previously published Rietveld refinement and is comparable with single crystal results. The degree of serial correlation in residuals has been determined by the use of the Durbin‐Watson d statistic. Normal probability plot based on δRi has been almost linear with the slope greater than one. The weighting scheme with wi = 1/yoi has proved to be good first approximation.
Etch features in bismuth germanate (Bi4Ge3O12) single crystal
Authors: Péter Á. , Polgár K. , Contreras L. , Dieguez E. 
Published: January 2007

AbstractThe three component mixture of HCl: HNO3: CH3COOH in the volumetric proportion of 3: 1: 4 was found to be a satisfactory etchant for various surfaces of Bi4Ge3O12. The correlation between etch pits and dislocations was established by means of repeated etching and optical observations.
Optical absorption behaviour of magnesium‐implanted GaAs
Authors: Hörig W. , Bouamama Kh. , Neumann H. , Nobes M. J. 
Published: January 2007

AbstractOptical absorption spectra of magnesium implanted GaAs single crystals are measured in the photon energy range below the fundamental absorption edge. It is found that the absorption coefficient increases with increasing fluence up to a saturation value of about 5 · 104 4 cm−1 at 1.36 eV. The results are compared with optical measurements on GaAs single crystals implanted with other ions.
Temperature dependences of the electrical conductivity and hall coefficient of indium telluride single crystals
Authors: Hussein S. A. 
Published: January 2007

AbstractConductivity type, carrier concentration and carrier mobility of InTe samples grown by Bridgmann technique were determined by the Hall effect and electrical conductivity measurements. The study was performed in the temperature range 150–480 K. Two samples with different growth rate were used in the investigation. The samples under test were P‐type conducting, in accordance with previous measurements of undoped material. The Hall coefficient was found to be isotropic yielding room temperature hole concentration in the range 1015 – 1016 cm−3. The hole mobilities of InTe samples were in the range 1.17 × 103 – 2.06 × 103 cm2/V · sec at room temperature. The band – gap of InTe determined from Hall coefficient studies has been obtained equal to 0.34 ev. The scattering mechanism was checked, and the electrical properties were found to be sensitive to the crystal growth rate.
A nematic two frequency adressing mixture with extremely low isotropy frequencies
Authors: Stettin H. , Kresse H. , Haas S. , Schäfer W. , Heidenreich G. , Zaschke H. 
Published: January 2007

AbstractNew liquid crystalline substances with four benzene rings have been synthesized. A nematic two frequency mixture containing some of these compounds was produced and dielectrically as well as electrooptically investigated. With dielectric measurements a very low frequent and distributed relaxation mechanism at room temperature could be estimated (fR = 0.0565 kHz, h = 0.25 at 294.2 K). Although new substances have been used the switching behaviour in a TN cell showed disturbances as on an earlier developed two frequency mixture.
Crystal and molecular structure of 1‐(p‐nitrophenyl)‐2‐acetylamino‐3‐brom‐propen‐2‐on‐1, C11H9BrN2O4
Authors: Ramm M. , Kuban R.‐J. , Schulz B. 
Published: January 2007

AbstractMr= 313.11, orthorhombic space group Pbca,a= 8.165(1),b= 9.491(2),c= 32.207(5) ÅV= 2496(1) Å3,DX= 1.667 Mgm−3,Z= 8, F(000) = 1248, λ(MoKα) = 0.71069 Å, μ = 32.7 mm−1. The crystal structure was determined by direct methods and refined by least‐squares procedure to the discrepancy factorR= 0.065. Positions of hydrogen atoms were calculated.The structure determined by x‐ray analysis confirms the chemical results.
Synthesis and characterization of ferroelectric magnesium hydrogen phosphate single crystals
Authors: Desai C. C. , Patel K. N. 
Published: January 2007

AbstractFerroelectric Magnesium Hydrogen Phosphate MgHPO4 (MHP) single crystals are grown by slow diffusion of magnesium chloride in sodium metasilicate gels impregnated with orthophosphoric acid. Bright and transparent prismatic, tabular, and isometric habit MHP crystals upto 3 × 2 × 1 mm3 are obtained. Results of chemical, X‐ray diffraction, EDAX, microhardness and magnetic analysis are reported. The average etch pit density is determined by chemical etching to be 7 × 103 cm−2. Microtopographic investigations revealed the mechanism of crystal growth.
Deformation behaviour of single crystals of GaP in uniaxial compression
Authors: Paufler P. , Retzlaff U. 
Published: January 2007

AbstractLEC n‐GaP:S single crystals were deformed in uniaxial compression parallel [321] and [110] direction. Plastic deformation by (111) slip has been observed between 511 °C and 717 °C. Indications for (111) twinning were obtained. Yield stress exhibits activation enthalpies U = Q(m + 2) and stress exponents m of U321 = (0.54 ± 0.05) eV, U110 = = (0.46 ± 0.05) eV, m = 1.1 ± 0.2 and m = 3 ± 1, respectively.
Oxidation of tetracyanonickellate (II) in the presence of organic cation
Authors: Oza A. T. 
Published: January 2007

AbstractA new material (TMPD)2Ni(CN)4I0.5 · H2O has been prepared (TMPD = N,N,N′,N′‐tetramethyl‐p‐phenylenediamine). The solution and mull absorption spectra in the infrared range indicate the presence of the redox process TMPD+ ⇌ TMPD2+ and tetracyanonickellate (IV) units.
Density studies across smectic‐smectic transitions in 70.6 and 80.10
Authors: Rao P. Bhaskara , Rao N. V. S. , Pisipati V. G. K. M. , Saran D. 
Published: January 2007

AbstractThe temperature dependence of density in N(p‐n‐heptyloxy benzylidene) p‐n‐hexylaniline (70.6) and in N(p‐n‐octyloxy benezylidene) p‐n‐decylaniline (80.10) is carried out to study the nature of the phase transitions associated density jumps, to estimate the pressure dependence of transition temperatures and pretransitional effects. The compounds 70.6 exhibits a phase variant ACFG whereas 80.10 exhibits a new phase sequence variant ABF. The isotropic‐smectic A, semctic A‐smectic B and semctic C‐smectic F phase transitions are found to be first order. The calculated thermal expansion coefficient also supported the density results. The density jumps, associated enthalpies and estimated pressure dependence of transition temperatures at the isotropic‐smectic A phase transformation in other compounds are presented.
Rare‐earth scandium garnets as an object of crystallization
Authors: Zharikov E. V. 
Published: January 2007

AbstractThe paper discusses the features of RESG which influence the crystal growth. RESG are nonstoichiometric compounds with complex scandium isomorphism which results in substantial variations of the crystallized composition. The presence of chrormuim ions in RESG strongly increases the absorption capability of the medium and leads to the rise of interface instability during the growth. The principle differences between ScGa‐ and ScAl‐garnets concerning crystallization features are considered.