bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric constants, refractive indexes and polarizations for acrylic esters +1‐alcohol binary mixtures at 298.15 and 308.15 K
Authors: Sastry Nandhibatla V. , Valand Mahendra K. 
Published: July 2012

AbstractDielectric constants and refractive indexes of binary mixtures of four 1‐alcohols (1‐heptanol, 1‐octanol, 1‐decanol and 1‐dodecanol) with three acrylic esters (methyl, ethyl and butyl acrylates) were measured at 298.15 and 308.15 K. The molar and orientation polarizations were calculated. The excess dielectric functions viz. excess dielectric constants, excess molar and orientation polarizations were evaluated. For a given ester the excess dielectric functions become less negative with the increase in the carbon chain length of 1‐alcohols. The variation of Kirkwood correlation factor, gK, with the ester mole fractions at 298.15 K for all the mixtures was examined. The results show that the disordering interactions are more predominant in the ester low regions followed by ester‐ester like interactions in the ester‐rich regions.
Adsorption of amide‐containing alkanethiols on gold
Authors: Zhang J. , Zhang H.L. , Chen M. , Zhao J. , Liu Z.F. , Li H.L. 
Published: July 2012

AbstractMonolayers of a new series of amide‐containing alkanethiol compounds, CH3(CH2)n‐2C(O)NHC2H4SH (referred as CnC2SH, n=4, 5, 5, 8), were self‐assembled from ethanol solutions onto gold and their structures have been characterized using the reflectance absorption infrared spectroscopy (RA‐FTIR) and wettability measurement. It has been proved that the CO and N‐H bonds are parallel to the gold surface and the orientations of alkyl chain in these Self‐Assembled Monolayers (SAMs) are perpendicular to the surface. The special orientation of the amide moiety and molecular axis are suggested to be attributed to the hydrogen‐bonding formed between the amide moieties of neighbor molecules. Meanwhile, wettability measurement reveals that the packing degree of the SAMs depends on the length of the alkyl chains in the thiol molecules. These results demonstrate that both the hydrogen‐bonding and the length of the alkyl chain exerts the tremendous influnece on the orientation of amide‐containing alkanethiol molecules. And also, it give us a way to control the molecular orientation in SAMs in molecular level.
LIF detection of the IO‐radical and kinetics of the reactions I+O3 → IO+O2, O(3P)+I2 → IO+I, O(3P)+CH3I → IO+CH3 and O(3P)+CF3I → IO+CF3 in the temperature range 230 to 310 K
Authors: Hölscher D. , Fockenberg Chr. , Zellner R. 
Published: July 2012

AbstractLaser induced fluorescence (LIF) from the (2,0) and (3,0) band of the A2∏3/2 ← X2∏3/2 transition of IO was detected. Using this detection, the rate constants for the reactions (1) I+O3 → IO+O2, (2) O(3P)+I2 → IO+I, (3) O(3P)+CH3I → IO+CH3 and (4) O(3P)+CF3I → IO+CF3 were determined. Reactions (1), (3) and (4) were investigated over me temperature range 230 to 310 K, whereas reaction (2) was measured only at 295 K. The rate constants for these reactions can be described by the following Arrhenius expressions:
Excited state electron transfer in 1,1′‐binaphthyl‐2,2′‐diyl‐phosphato‐pentaamminecobalt(III)
Authors: Kunkely Horst , Vogler Arnd 
Published: July 2012

AbstractThe phosphate ester 1,1′‐binaphthyl‐2,2′‐diyl‐phosphate shows an intense fluorescence of the binaphthyl moiety. In the complex 1,1′‐binaphthyl‐2,2′‐diyl‐phosphato‐pentaammine‐cobalt(III) this emission is quenched by excited state electron transfer to Co(III). As a consequence the phosphate ester undergoes an oxidative cleavage while Co(III) is reduced to Co(II) with ϕ = 0.023±0.002 at λirr=313 nm.
Picosecond IR study of the UV photo‐induced decomposition of Bis(naphthoyl)peroxide and of a naphthyl peroxycarbonate
Authors: Aschenbrücker J. , Buback M. , Ernsting N.P. , Schroeder J. , Steegmüller U. 
Published: July 2012

AbstractPicosecond UV pump/IR probe experiments were carried out on bis(1‐naphthoyl)peroxide (1) and on tert‐butyl‐peroxy‐2‐naphthylcarbonate (2) dissolved in CCl4. After excitation by a 308 nm pulse the formation of CO2 is measured with a time resolution of 1.8 ps via the IR‐absorption of the v3‐mode at around 2340 cm−1 for delay times up to 550 ps. A pronounced temporal and spectral evolution of the v3‐absorption band of CO2 is found which is assigned to the initial formation of vibrationally excited CO2 and subsequent vibrational cooling by energy transfer to the surrounding solvent. CO2 concentration versus time profiles are obtained from the time dependence of the integrated v3‐band absorbance. The data suggest that 2 decomposes in a consecutive stepwise process whereas 1 undergoes concerted bond scission leading to CO2 formation within the time resolution of the experiment.
Elementary reactions in molecular ions — from thermal towards state‐selective experiments
Authors: Weitzel Karl‐Michael 
Published: July 2012

AbstractTwo important classes of experiments aimed at the energetics, kinetics and the mechanism of unimolecular reactions of molecular ions are discussed. The first kind of experiment is based on a thermal sample of molecules. As an example the energetically lowest reaction channel in the ethane ion, i.e. the H2 loss reaction, is presented. The second kind of experiment deals with state‐selected ions. Here as an example the photodissociation of HBr* ions is discussed.
The [4+2]‐cycloaddition of singlet oxygen (1Δg) to aromatic hydrocarbons: An Easy Method for Determination of Oxygen Concentrations in Organic Solvents
Authors: Neumann Marcus , Hild Markus , Brauer Hans‐Dieter 
Published: July 2012

AbstractBy determination of the photooxidized amount of a singlet oxygen (1Δg) acceptor one can calculate the oxygen concentration in solution. Rubrene was used as acceptor due to its photochemical properties. Acceptor concentrations were determined both gravimetrically and photometrically: Using this new method, the oxygen solubility was examined in nine aromatic solvents. The solubility parameters have been verified by an indirect method based on the diffusion‐controlled fluorescence quenching of pyrene by ground state oxygen. The rate constants are compared with the prediction of the Stokes Einstein equation for a diffusion‐controlled process.
Interaction between Cl− and linear and branched polyethyleneimine in aqueous solution studied by 35Cl‐ and 37Cl‐NMR
Authors: Meier Urs , Schläpfer Carl Wilhelm 
Published: July 2012

AbstractCounter anion condensation in solutions of LPEI (linear polyethylene imine) and BPEI (branched polyethylene imine) was studied by 35Cl‐ and 37Cl‐NMR relaxation as a function of the charge density of the polycation, which is controlled by the degree of protonation of the polybase determined by the pH of the solution. The condensation in BPEI solutions is proportional to the degree of protonation. In LPEI solutions the counterion condensation is controlled by the charge and conformation of the polyion in solution, which changes upon protonation.
Electrochemically induced surface changes on microstructured Pt films on a Solid YSZ electrolyte
Authors: Poppe J. , Schaak A. , Janek J. , Imbihl R. 
Published: July 2012

AbstractThin (500 Å) microstructured Pt films on single crystalline yttrium stabilized zirconia (YSZ) prepared by photolithography have been used to study the processes at the interface between the solid electrolyte and the Pt film when electrical potentials are applied. The experiments are performed under UHV conditions with a standard three‐electrode set‐up employing photoemission electron microscopy (PEEM) as spatially resolving method. Upon electrochemical “pumping” of oxygen by applying a positive electric potential to the Pt film we observe in PEEM a darkening of the Pt film reflecting a work function (WF) increase; a negative potential leads to a WF decrease. No time‐dependent spatial concentration profiles which would have been indicative of the slow diffusional spreading of a spillover species were observed.
Investigation of the crystallization of lead titanate and lead zirconate titanate with X‐ray diffraction and differential thermal analysis
Authors: Merkle R. , Bertagnolli H. 
Published: July 2012

AbstractLead titanate (PT) and lead zirconate titanate (PZT) were prepared by the sol‐gel process from lead acetate and zirconium and titanium n‐propoxide dissolved in 2‐methoxyethanol. After pyrolysis of the organic residues, the crystallization kinetics were investigated. In situ X‐ray diffraction of the isothermal crystallization yields Avrami‐exponents of ≈︁ 3 for the perovskite formation of titanium‐rich samples. Both the pyrochlore and the perovskite formation of zirconium rich samples exhibit Avrami exponents of ≈︁ 1. Investigation of the non‐isothermal crystallization with differential thermal analysis (DTA) yields Avrami exponents that are similar to the isothermally determined values. The activation energy is 500 kJ/mol for the formation of the pyrochlore phase, and 300–350 kJ/mol for the formation of the perovskite phase. Possible crystallization mechanisms are discussed.
Novel general linear concentration rules and their theoretical aspects for multicomponent systems at constant chemical potentials — Ideal‐Like Solution Model and Dilute‐Like Solution Model
Authors: Wang Zhi‐Chang 
Published: July 2012

AbstractGeneral simple rules have been established both for binary and higher‐order systems related to their pure components and for ternary and higher‐order systems related to their binary subsystems. In this paper we present two new general linear concentration rules, together with their strict thermodynamic aspects and main statistical explanations, for the real systems {A1+A2+…+Aq+B+C+…+Z} related to their subsystems {A1+A2+…+Aq+i} (i∈{B,C,…,Z}) at constant chemical potentials of A1, A2,…,Aq. One of the linear rules holds good for the real system having zero interchange energy among B, C,…,Z, while the other linear rule, for the real system, having nonzero interchange energies among them. In the simplest case of q=1, they are identical with Zdanovskii's rule for mixed electrolyte aqueous solutions, semi‐ideal hydration model for mixed nonelectrolyte aqueous solutions, linear solubility equation for carbon in ternary alloys, and Wang's general linear concentration rules and corresponding solution models for the real systems {A+B+C+…+Z} related to their binary subsystems {A+i} at constant chemical potential of A, respectively, which quantitatively fit the literature experiments for organic and organic‐inorganic mixtures, aqueous and nonaqueous solutions, alloys, molten salt mixtures, slags and nonstoichiometric solid compounds under normal and supercritical conditions. In order to verify their applicabilities at q≥2, isopiestic measurements for fifteen quaternary and quinary aqueous solutions, each containing two unsaturated solutes and one or two saturated solutes, and joint solubility measurements for four quaternary systems, each containing two saturated solutes and two organic solvents, are reported at T=298.15 K. The experimental results are in excellent agreement with the new linear rules.
Reconciling ab initio and semiempirical approaches to lattice stabilities
Authors: Grimvall Göran 
Published: July 2012

AbstractStarting around 1970, two methods have been developed that may give information about the lattice stability Hα/βHα–Hβ, i.e. the enthalpy difference between two phases, α and β, of a pure element or compound. The ab initio method is purely theoretical and relies on electron structure calculations. The CALPHAD method derives a Gibbs energy function GHTS from experimental thermodynamic data, including phase diagrams. A long‐standing problem has been that the two methods gave very different lattice stabilities for some transition metals, e.g., W. The reason for this discrepancy has recently been clarified, when the role of dynamical lattice instabilities was realised. This paper gives an account of how the discrepancy emerged and is now resolved. The interpretation and practical applicability of the Gibbs energy function in the CALPHAD approach to systems containing dynamical instabilities is clarified.
Thermodynamic description of the stable Pb‐Sn‐Zn and the metastable Al‐Cu‐Mg miscibility gaps
Authors: Hurtado I. , Jantzen T. , Spencer P.J. 
Published: July 2012

AbstractThe ternary system Pb‐Sn‐Zn displays a large miscibility gap in the liquid phase which extends from the binary system Pb‐Zn. The calculated isothermal sections at 714, 757, 805, 842 and 877 K, in which two liquid phases are shown to exist in equilibrium with each other, will be presented and compared with experimental data. The calculated activities of Zn in the liquid phase for different isopleth sections are in good agreement with experimental data.The appearance of GP Zones in Al‐Cu‐Mg alloys may be described by a Gibbs energy function which predicts a miscibility gap in the fcc (Al) phase. The new function was first obtained for the binary Al‐Cu system and then extended into the ternary to describe the precipitation of GPZB zones. The Thermo‐Calc calculation package was used for this purpose.
Contribution of the electron subsystem state variations to the melting entropy of covalent crystals
Authors: Glazov V. M. , Koltsov V.B. 
Published: July 2012

AbstractAnalysis of the whole complex of the electrophysical and thermodynamic properties of semiconductors allowed us to conclude that melting entropy can be presented by three basic components, i.e. by the position, vibration and electron contributions. Possible methods of calculating the above contributions have been discussed, e.g. it has been shown that the electron contribution to the melting entropy of semiconductors that are metallized makes up a considerable part of the total melting entropy, which accounts for the anomalous values of the melting entropy of the substances discussed.
The enthalpy of formation and the heat capacity of liquid and undercooled liquid Al‐Cu‐La alloys
Authors: Zhou S. H. , Sommer F. 
Published: July 2012

AbstractThe integral enthalpy of mixing δH of liquid lanthanum‐rich and aluminium‐rich Al‐Cu‐La alloys was determined by solution calorimetry at 1078 K. An adiabatic calorimeter was used to measure the heat capacity Cp of liquid Al25Cu20La55 and Cu67La33 alloys. The association model was applied to calculate the thermodynamic functions of liquid Al‐Cu‐La alloys using the model parameter of the three limiting binary alloys. The results show systematic positive deviations from the experimental data. An additional ternary association reaction was assumed with a stoichiometry near to the composition of maximum deviation between calculated and experimental ΔH values. The new description reveals a good agreement with the experimental ΔH(x, 1078) and the Cp(x, T) data. The calculated Cp(T) curve of the undercooled liquid Al25La55Cu20 alloy exhibits a maximum.
Phase equilibria in aluminum‐carbon system at high temperatures
Authors: Gokcen N. A. , Oden L. L. 
Published: July 2012

AbstractThe partial excess Gibbs energies of carbon and aluminum in liquid Al‐C were used with the equilibrium vapor pressures of pure Al and pure C to obtain the phase diagrams (1) at 1 bar of total pressure, and (2) at pressures sufficient to suppress the gas phase. The first diagram contains [gas+graphite → liquid] tectoid‐type reaction at 2900±20K with the tectoid composition of 0.681 mol fraction of aluminum. The [gas/graphite] boundary is subject to large errors due to the large errors in the vapor pressure of pure graphite, but its general form is acceptable. The second diagram consists entirely of the condensed phases with peritectic reaction [liquid+graphite → Al4C3] at 2429 K. The [liquid/graphite] phase boundary was obtained from the graphite solubility in liquid solutions at 2429‐2800 K, yielding the partial excess Gibbs energy of carbon in solution.The resulting phase boundary is as reliable as the melting point of graphite, taken to be 4130 K.
Experimental and thermodynamic investigations in the Ti‐Si‐C system
Authors: Du Yong , Schuster J. C. 
Published: July 2012

AbstractThe Si‐rich part of the 1100°C isothermal section and the isopleths at 5, 10 and 15 at.% C in the Ti‐Si‐C system were determined by means of DTA and XRD techniques. Two ternary eutectic reaction temperatures (1330°C for LSi+SiC+TiSi2 and 1485°C for LTiSi+TiSi2+Ti5Si3Cx) and three transition reaction temperatures (1485°C for L+Ti5Si3CxTi3SiC → 2+TiSi2, 1473°C for L+Ti3SiC2TiSi2+SiC, and 1341°C for L+TiCbcc‐(Ti)+Ti5Si3Cx) were observed. The decomposition temperature of the ternary compound Ti3SiC2 was determined by using a Pirani technique. By considering the experimental results from the present work and literature data, a consistent thermodynamic data set for the Ti‐Si‐C system was obtained.
Gibbs energy of formation of sic: A contribution to the thermodynamic stability of the modifications
Authors: Kleykamp Heiko 
Published: July 2012

AbstractThe Gibbs energy of formation ΔfGo of hexagonal α‐SiC was determined by electromotive force (emf) measurements between 1200 and 1300 K using the galvanic cell Si, SiO2|Th(Y)O2|SiO2, α‐SiC, C which gives (T in K): ΔfGo (α‐SiC) =‐94770+24.24·T J/mol. The third‐law enthalpy of formation was calculated as ΔfHo298 (α‐SiC)=‐74.4 kJ/mol at 298 K. In order to examine more closely the relative stability of α‐SiC and cubic β‐SiC, Gibbs energy of transformation ΔtrG measurements were made by the same method between 1100 and 1300 K using the cell β‐SiC, C, SiO2|Th(Y)O2|SiO2, C, α‐SiC. An emf of about 20 mV of the meta‐stable cell was measured up to 5 h cell operation. This observation implies that α‐SiC is the more stable modification in the investigated temperature range yielding ΔtrG (βα‐SiC) ≈︁ −8 kJ/mol at 1200 K.
The nickel‐rich part of the Ga‐Ni phase diagram and the corresponding phase relations in the ternary Ga‐Ni‐Sb system
Authors: Micke K. , Markovski S. L. , Ipser H. , van Loo F.J.J. 
Published: July 2012

AbstractIn the past years, metal/III‐V compound semiconductor interfaces have been investigated intensively in order to find a suitable metallization scheme meeting the required performance, reproducibility and stability criteria. Equilibrium phase diagrams provide a base for understanding the interfacial reactions, hence solid state equilibria at 600 and 900°C in the Ga‐Ni‐Sb system have been experimentally determined and are presented in this article. In the course of the work the nickel‐rich part of the Ga‐Ni phase diagram has been revised by means of DTA and the diffusion couple technique. This study was undertaken to clarify the true temperature range of stability for the compounds Ga2Ni3 and Ga9Ni13 that is of significant importance for establishing the Ga‐Ni‐Sb phase diagram.
The ternary Ga‐Pd‐Sb phase diagram: A system relevant to contact materials for GaSb
Authors: Richter K. W. , Ipser H. 
Published: July 2012

AbstractThe phase relationships of GaSb in the ternary system Ga‐Pd‐Sb were studied for an isothermal section at 500°C by means of X‐ray diffraction (XRD) and electron probe micro analyses (EPMA). Eight invariant ternary phase reactions, i.e. three quasibinary eutectic reactions, three ternary transition reactions and two ternary eutectics were identified by means of differential thermal analyses (DTA). All experimental phase diagram informations were combined to construct a complete reaction scheme (Scheil diagram) in the investigated composition area and the liquidus surface was derived based on the results of the DTA measurements. The gallium‐rich part of the limiting binary Ga‐Pd system was reinvestigated by means of DTA and XRD.
Experimental investigations of the enthalpies of formation of Zr‐based metallic amorphous binary and ternary alloys
Authors: Turchanin A. A. , Tomilin I. A. 
Published: July 2012

AbstractThe enthalpies of formation of amorphous Zr‐Cu, Zr‐Ni, Zr‐Cu‐Al, Zr‐Ni‐Al and Zr‐Ni‐Ti alloys from pure crystalline elements at 298 K were measured in an isoperibolic Calvet‐type solution calorimeter which is operating in the temperature range 298–1300 K. The alloys of the following compositions were investigated:Zr1‐xCux (x = 0.30, 0.40, 0.50, 0.60, 0.65, 0.70)Zr1‐xNix (x = 0.33, 0.40, 0.67)(Zr0.65Cu0.35)1‐x (Zr0.65Cu0.35)x (x = 0, 0.10, 0.20, 0.40, 0.50, 0.60, 0.70, 0.80)(Zr0.60Ni0.40)1‐x (Zr0.60Ni0.40)x (x = 0, 0.125, 0.250, 0.374, 0.500)(Zr0.33Ni0.67)1‐x (Ti0.33Ni0.67)x (x = 0, 0.15, 0.30, 0.45)The results are discussed in comparison with thermodynamic data about enthalpies of formation of liquid alloys and intermetallic compounds available in the literature. In all investigated systems the enthalpies of formation show great negative values and a strong chemical interaction between the atoms.
Measurements of thermophysical properties of solid and liquid Fe‐Ni alloys
Authors: Seifter A. , Pottlacher G. , Jäger H. , Groboth G. , Kaschnitz E. 
Published: July 2012

AbstractEnthalpy, resistivity and density as a function of temperature of binary Fe‐Ni alloys have been measured by a fast resistive pulse heating technique. Six different concentrations, including Invar‐type alloy, have been investigated to cover the entire range of the phase diagram. The temperature range was from room temperature to 2400 K.
Thermodynamic study of CaO‐Sb2O3 system by emf method
Authors: Katayama I. , Kemori N. , Denholm W. T. 
Published: July 2012

AbstractThe emf of the following galvanic cells with stabilized zirconia solid electrolyte was measured to determine the calcium antimonites which can coexist with liquid antimony in the temperature range 930−1100 K; (−)Pt, Re|Sb(1), two phases in CaO‐Sb2O3 system | O2− | air, Pt(+) Equilibrium oxygen pressures are obtained as follows:3/2RT In PO2/kJ = −687.5+0.2433 T/K±0.6 for Sn, Sb2O3;−817.8+0.2402T/K±0.6 for Sb(1), 4CaO·Sb2O3, CaO;−800.5+0.2463T/K±0.6 for Sb(1), 4CaO·Sb2O3, 2CaO·Sb2O3;−762.5+0.2828T/K±0.5 for Sb(1), 2CaO·Sb2O3, CaO·Sb2O3;−690.5+0.2436T/K±1.0 for Sb(1), CaO·Sb2O3, Sb2O3.Standard Gibbs free energies of formation of double oxides coexisting with liquid antimony from CaO(s) and Sb2O3 are derived as follows:4CaO(s)+Sb2O3(1)=4CaO·Sb2O3(s); ΔG°/kJ = −130.3−0.0031 T/K2CaO(s)+Sb2O3(1)=2CaO·Sb2O3(s); ΔG°/kJ = −121.7−0.00005 T/KCaO(s)+Sb2O3(1)=CaO·Sb2O3(s); ΔG°/kJ = −98.3+0.0197 T/K.The activities of Sb2O3 and CaO in the two phase regions at 1000 and 1100 K are derived and the most stable double oxide is CaO·Sb2O3 in this system. By an X‐ray diffractometry, it was found that 3CaO·Sb2O3(s) cannot coexist with Sb(1).
Development of Si‐B‐C‐N ceramics supported by phase diagrams and thermochemistry
Authors: Seifert Hans Jürgen , Lukas Hans Leo , Aldinger Fritz 
Published: July 2012

AbstractTo explain the crystallization behaviour and phase relationships of precursor derived Si‐B‐C‐N ceramics, In (pN2)‐Tdiagrams were calculated. The results can be used to optimize the chemical composition and the physico‐chemical conditions for heat treatment. Stabilization of specific phase assemblages requires careful adjustment of the N2partial pressure during heating and cooling. The high thermal stability of silicoboron carbonitrides can be explained by their particular microstructure and the resulting stabilization of Si3N4.