Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural and Dynamical Properties of Zincblende GaN

The structural and dynamical properties of zincblende β-GaN are calculated within a three-body Tersoff potential coupled with a molecular-dynamics simulation scheme for a temperature ranging from 300 to 900 K. A good agreement between the calculated and experimental values of the lattice constant, the bulk modulus and its derivative, and the cohesion energy are obtained. We have also calculated the lattice constants, lattice thermal expansion, and specific heat. In order to elucidate the microscopic behavior of mobile atoms with temperature, the diffusion mechanism has been predicted using this scheme. The structural properties of GaN in the rocksalt structure are also studied and compared with other works.
Density Functional Theory Prediction of the Relative Energies and Isotope Effects for the Concerted and Stepwise Mechanisms of the Diels−Alder Reaction of Butadiene and Ethylene

Density-functional theory has been applied to the study of the mechanism of the Diels−Alder reaction of butadiene and ethylene. Both synchronous concerted and two-step diradical mechanisms were studied at the Becke3LYP/6-31G* level. The lowest energy stepwise pathway has a free energy of activation 7.7 kcal/mol above that of the concerted path. Spin correction of the spin-contaminated diradical transition structure energy reduces this energy difference to 2.3 kcal/mol. A study of the H2 potential energy surface suggests that the spin-projection procedure overcorrects the energies of diradical species; the diradical energies likely fall between the corrected and uncorrected values. Thus, the free energy of concert for the Diels−Alder reaction is predicted to be between 2.3 and 7.7 kcal/mol, in excellent agreement with thermochemical estimates. Energies of reaction and geometries of the reactants and product are in good agreement with available experimental results. Calculated secondary kinetic isotope effe.
Kinetic Model for the Etherification of Isoamylenes with Methanol

The kinetics of the formation of tert-amyl methyl ether (TAME; 2-methoxy-2-methylbutane) was investigated in a batch reactor, using a commercial ion-exchange resin (Amberlyst 16) as catalyst. The effect of the methanol/isoamylene ratio on the etherification rate was measured at temperatures between 333 and 353 K. The initial rates of isomerization of 2-methyl-1-butene to 2-methyl-2-butene and the etherification of 2-methyl-1-butene to TAME were measured in the absence of 2-methyl-2-butene in the feed. The initial rate of etherification was found to be 2.3−2.7 times that of isomerization. The experimental results were best described by kinetic equations, which were based on a mechanism where the alcohol and the ether adsorbed on the catalyst surface and the isoamylenes reacted from the bulk liquid phase. The kinetic equations were written in terms of activities, using the UNIQUAC method for activity coefficient calculation. The activation energy was determined to be 81.6 kJ/mol for the isomerization and 72.
Engineering coordination polymers towards applications

The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.
Economic analysis of rosemary, fennel and anise essential oils obtained by supercritical fluid extraction

In the present work, economic analysis of the production of extracts and essential oils of rosemary (Rosmarinus officinalis), fennel (Foeniculum vulgare) and anise (Pimpinella anisum) by supercritical fluid extraction and steam distillation are discussed. The manufacturing cost (COM) was determined considering that the COM can be obtained in terms of the costs of investment, operational labour, raw materials, waste treatment and utilities. The manufacturing cost was also estimated considering that the essential oil content in SFE extracts varies (50–100%). The analysis showed that the supercritical fluid extraction is economically viable to obtain these vegetable extracts and essential oils. The higher costs of essential oils obtained by steam distillation were mainly caused by the lower yield and the higher energy consumption of this process. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of High Pressure Treatment on Rheological Characteristics of Egg Components

The objective of this study was to evaluate the effect of high pressure treatment on rheological properties of various egg components (i.e., egg white, egg yolk, and whole liquid egg). A five-level central composite design with three independent variables (pressure, 281.8–618.2 MPa; temperature, 8.2–41.8°C; pressure holding time, 1.6–18.4 min) was employed. Samples were packed in plastic pouches, heat sealed, and subjected to pressure treatment in an isostatic press. Shear and time-dependent rheological properties were evaluated using a 3-segment (each 5 min) program with the shear rate initially increasing from zero to 100 s−1 (upward curve), then held at 100 s−1 (hold curve), and finally decreasing from 100 to 0 s−1 (downward curve) using a parallel plate rheometer. Power law model was fitted to the upward (virgin) and downward curves while Weltman time dependency model was fitted for the hold curve (R2 > 0.90). Rheological properties were most significantly affected by pressure followed by holding time and temperature for all egg components. In general, they showed thixotropic shear thinning behavior and reduction in time dependency, which was dependent on the level of processing treatment used (combination of pressure, time, and temperature level). The high pressure treatment resulted in a progressive transition of egg components from flowable liquid-like behavior (218–350 MPa) to semi-viscous (350–500 MPa) to highly-viscous (500–618 MPa) behavior. Rheology-based optimal conditions satisfying HP pasteurization needs were identified.
Organization of Vanadyl and Metal-Free Tetraphenoxyphthalocyanine Complexes on Highly Oriented Pyrolytic Graphite in the Presence of Paraffinic Solvents: A STM Study

Scanning tunneling microscopy (STM) is employed to demonstrate that the presence of the vanadyl ion (VO2+) in the 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine complex (VOPcPhO) has a pronounced effect on the organization of the complex at the highly oriented pyrolytic graphite (HOPG)−n-alkyl benzene (n = 6, 7, 8, and 10) interface. VOPcPhO forms at least three different stable architectures, as compared to only one type of structure resulting from the adsorption of the metal-free tetraphenoxyphthalocyanine analog (H2PcPhO) on HOPG under conditions similar to VOPcPhO. All three observed VOPcPhO monolayer structures have high packing density and are commensurate with the underlying graphite lattice, whereas H2PcPhO forms a lower packing density incommensurate adlayer. The VOPcPhO structures display a small rectangular unit cell (1 molecule/cell) with lattice vector lengths of 1.28 and 1.48 nm, a larger rectangular unit cell (6 molecules/cell) with lattice vector lengths of 4.43 nm 2.98 nm, and an oblique u.
Modeling /sup 13/N-ammonia from projections in rat-PET studies

Positron emission tomography (PET) image reconstruction techniques introduce inaccuracies in images, especially in dynamic acquisitions where the frame length is short and/or when the radioactivity emission is low. To avoid these inaccuracies in PET kinetic modeling, kinetic parameters can directly be obtained from the sinograms. The work describes modeling /sup 13/N-ammonia in the sinograms obtained in rats with the Sherbrooke small animal PET scanner. Rats of nearly 250 g were injected approximately 5 mCi of /sup 13/N-ammonia during 30 sec and scans were acquired in 20 min. Each bin of the dynamic sinograms was decomposed in its basis functions using spectral analysis technique in conjunction with the /sup 13/N-ammonia kinetic model. Components of homogeneous structures were obtained as well as the kinetic model parameters. Structures were identified according to their frequencies and they were individually reconstructed. Compartments of blood, non-metabolized and metabolized ammonia were clearly separated. Moreover, blood components having different shapes were discriminated and their time activity curves showed a delay in the occurrence of their peaks. In conclusion, modeling in the sinogram domain allows one to extract a specific component and to obtain images of kinetic parameters.
New Thermotropc Liquid Crystalline Polyazomethines Containing Luminescent Mesogens

Thermotropic liquid crystalline polyazomethines containing 1,3,4‐oxadiazole chromophors have been synthesized. These polymers are semiflexible liquid crystalline compounds containing luminescent mesogens. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide angle X‐ray diffraction (WAXD) have been used to evaluate their thermal and mesomorphic properties. The target polyazomethines present liquid crystalline behavior with classical calamitic textures, large mesophase range, and high thermal stability. The investigation of the optical properties of the synthesized polymers, in solution and solid state, confirmed a blue fluorescence.
Effects of liquid immiscibility on trace element fractionation in magmatic iron meteorites: A case study of group IIIAB

— Magmatic iron meteorites are generally agreed to represent metal that crystallized in asteroidal cores from a large pool of liquid. Estimates suggest that the metallic liquid contained significant amounts of S and P, both of which are incompatible and exert a strong effect on trace element partitioning. In tandem, S and P are also prone to cause immiscibility between sulfide liquid and P-rich metal liquid. The liquid immiscibility field occupies ∼70% of the portion of the Fe-Ni-S-P system in which Fe is the first phase to crystallize. In spite of this, previous fractional crystallization models have taken into account only one liquid phase and have encountered significant discrepancies between the meteorite data and model values for the key elements Ni, Ir, Ga, Ge and Au at even moderate degrees of fractionation. For the first time, a model for trace element partitioning between immiscible liquids in the Fe-Ni-S-P system is presented in order to assess the effects on fractionation in magmatic iron meteorite groups. The onset of liquid immiscibility causes a significant change in the enrichment patterns of S and P in both liquids; so elements with contrasting partitioning behavior will show trends deviating clearly from one-liquid trends. A trend recorded in the solid metal will either be a smooth curve as long as equilibrium is maintained between the two liquids or the trend may diverge into a field limited by two extreme curves depending on the degree of disequilibrium. Bulk initial liquids for most magmatic groups have S/P (wt%) ratios well below 25. In these cases and due to the constitution of the Fe-Ni-S-P system, most of the metal will crystallize from the rapidly decreasing volume of metal liquid and only a subordinate amount from the sulfide liquid. Because of the strong extraction of P into the metal liquid, P will have a much larger influence on trace element partitioning than a low initial P content might suggest. My model calculations suggest that liquid immiscibility played a significant role during the solidification of the IIIAB parent body's core. The two-liquid model reproduces the IIIAB trends more closely than previous one-liquid models and can account for: (a) the general widening of the IIIAB trend with increasing Ni and decreasing Ir contents, (b) the occurrence of high-Ni members that are not strongly depleted in Ir, Ga and Ge; and (c) an upper limit at ∼11 wt% Ni where the metal liquid was almost consumed.
A Black-oil Three-phase Model With Capillary Effects

Abstract The black-oil (BO) model for compositional effect in three-phase compressible flow with capillary pressure is discussed. The compositional framework is used in modeling of a BO that allows extending a BO model to a compositional model and vice versa. A total compressibility condition is defined for saturated and unsaturated cases when the capillary effects are not ignored.
The Velocity Dependence of Dynamic Capillary Pressure During Imbibition Displacement in Microscale Quartz Capillaries

Studies have been done to elucidate the velocity dependence of dynamic capillary pressure in the process of water displacing oil under constant pressure drops in hydrophilic capillaries with 0.92 μm in radius. Experimental results show that this dependence is closely correlated with the relative viscosities of the liquids involved. When the liquids are equal in viscosity, the displacement proceeds with constant rate and the dynamic capillary pressure stays almost unchanged, while it increases gradually with a increase in velocity in the case of water displacing more viscous oil, in contrast, it decreases gradually with a reduction in velocity when water displaces less viscous oil.
Synthese von Pyrrolo[1,2‐a]chinazolinonen, Indolo[1,2‐a]chinazolinonen, Pyrrolo[1,2‐a]thieno[3,2‐e]pyrimidinonen, Benzothieno[3,2‐e]‐pyrrolo[1,2‐a]pyrimidinonen und 6H‐Cyclohepta[4,5]thieno‐[3,2‐e]pyrrolo[1,2‐a]pyrimidinonen

A Synthesis of Pyrrolo[1,2-a]quinazolinones, Indolo[1,2-a]-quinazolinones, Pyrrolo[1,2-a]thieno[3,2-e]pyrimidinones, Benzothieno[3,2-e]pyrrolo[1,2-a]pyrimidinones and 6H-Cyclohepta[4,5]-thieno[3,2-e]pyrrolo[1,2-a]pyrimidinones α-Cyano-γ-halo-crotonnitriles (1) synthesized (e.g. via Knoevenagel reaction and by subsequent halogenation) react with primary arylamines (2) to substituted 1-aryl-2-amino-3-cyano-pyrroles (3). We found that the reaction yields pyrrolo[1,2-a]quinazolin-5-ones (6) in a one-pot procedure if anthranilic esters (4) and compounds of the general formula 5 are used. The analogous treatment with 2-amino-3-ethoxy-carbonyl-thiophene derivatives (8) leads to pyrrolo[1,2-a]thieno-[3,2-e]pyrimidin-5-ones, benzothieno[3,2-e]pyrrolo[1,2-a]pyrimidinones and 6H-Cyclohepta[4,5]-thieno[3,2-e]pyrrolo[1,2-a]pyrimidinones as thiadiazastereoid analogs 9. This reaction is suitable for the synthesis of various heterocyclic ring systems.
210Po, an atmospheric tracer of long‐range transport of volcanic plumes

With the aim of testing the ability of 210 Po to be a tracer of volcanic aerosol plumes, we collected air samples during an oceanographic cruise around the Indonesian arc and measured the radioactivity of 210 Po. Owing to the atmospheric circulation pattern and geographical distribution of 210 Po sources around the sampling site, the origin of 210 Po of the samples could be determined by calculating 5-day backward air mass trajectories. It is shown that the signature of 210 Po originating from volcanic emissions is distinct from that of 222 Rn decay, even though these processes are the 2 major sources of atmospheric 210 Po. Moreover, the proportion of 210 Po in a given air parcel is conservative during the transport: as other aerosols, 210 Po aerosols are very sensitive to the atmospheric removal processes and the production and the loss of 210 Po by radio decay within an air parcel is negligible. Our results confirm that 210 Po is a good tracer for aerosols emitted by volcanoes. DOI: 10.1034/j.1600-0889.49. issue4.8. x
Discrimination of Inner- and Outer-Sphere Electrode Reactions by Cyclic Voltammetry Experiments

A laboratory experiment for undergraduate students who are studying homogeneous and heterogeneous electron-transfer reactions is described. Heterogeneous or electrode reaction kinetics can be examined by using the electrochemical reduction of three FeIII/FeII redox couples at platinum and glassy carbon disk electrodes. Cyclic voltammetric measurement is suitable for determining the electrode-reaction rate constants. The dependence of the rate constant on the electrode materials enables the students to discriminate and discuss the mechanism of the electrode reaction. The experiment is completed in a 5-h laboratory period for pairs of students in analytical chemistry lab class. This material is also suitable for an inorganic chemistry lab class.
Effect of Ca2+, cyclic GMP, and cyclic AMP added to artificial solution perfusing lingual artery on frog gustatory nerve responses

The lingual artery of the bullfrog was perfused with artificial solution and the effects of Ca2+, Ca-channel blockers (MnCl2 and verapamil), cGMP, and cAMP added to the perfusing solution of the gustatory nerve responses were examined. The responses to chemical stimuli of group 1 (CaCl2, NaCl, distilled water, D-galactose, and L- threonine) applied to the tongue surface were greatly decreased by a decrease in Ca2+ concentration in the perfusing solution, suppressed by the Ca-channel blockers, enhanced by cGMP, and suppressed by cAMP. The responses to chemical stimuli of group 2 (quinine hydrochloride, theophylline, ethanol, and HCl) were practically not affected by a decrease in Ca2+ concentration, the Ca-channel blockers, cGMP, and cAMP. The responses to the stimuli of group 1 seem to be induced by Ca influx into a taste cell that is triggered by depolarization and modulated by the cyclic nucleotides in a taste cell. The responses to group 2 seem to be induced without accompanying Ca influx.
Zincate-Free, Electroless Nickel Deposition on Aluminum Bond Pads

A zincate-free electroless nickel deposition on aluminum bond pads is investigated. A three-step, etch, rinse, and electroless plating, is demonstrated for deposition on aluminum bond pads patterned with polyimide. The chemicals used are compatible with this dielectric material. The deposition has been achieved with good selectivity, uniformity, and deposition rate at 40 × 40 μm aluminum bond pads. The adhesion and contact resistance were also determined and improved through anneals in the range 200-400°C for 1 h. The optimized condition for adhesion and contact resistance was an anneal at 400°C. The combination of a nickel hypophosphite reducing agent and the additives used leads to an active plating bath in the early stages of deposition, by comparison with commercial solutions, and hence, good coverage of the aluminum bond pad using the simplified process.
Unique physical–chemical, apatite-forming properties and human marrow mesenchymal stem cells (HMSCs) response of sol–gel bioactive glass microspheres

Bioactive glasses (BGs) are thought to be promising materials for bone tissue repair and regeneration because of their osteoconductive, osteoproductive and osteoinductive properties. Comparing with melting bioglass, sol–gel bioactive glasses (SGBGs) have been developed for bone tissue regeneration as they have the unique micro-nanoscale structure and high bioactivity in vitro. In this paper, we fabricated bioactive glass microspheres (BGMs) by a sol–gel-polymer template technology, and firstly studied the effects of morphology on their properties (physical–chemical, apatite-forming and biological properties) in detail. The surface morphology and structure, degradation, apatite-forming bioactivity and biocompatibility of BGMs were evaluated. The results revealed that the BGMs have a uniformly spherical morphology (2–6 μm in diameter) and improved amorphous structure. Comparing with irregular bioactive glass (IBG), BGMs showed slow and stable silicon release kinetics and pH stability in simulated body fluid (SBF). More uniform and needle flake-like apatite was formed on the surfaces of the BGMs. The attachment and proliferation of human marrow mesenchymal stem cells (HMSCs) cultured on the surfaces of BGMs in a short time were significantly higher than on IBG. HMSCs’ osteogenic differentiation was enhanced significantly by the BGMs, as implied by ALP activity, without adding any inducing factor, compared with IBG. Thus, BGMs possess excellent physical-co-chemical and biological properties, exhibiting their potential applications in bone tissue regeneration and drug release systems.
Aluminum(III), gallium(III), and indium(III) 4-hydroxyacridinato complexes

4-Hydroxyacridine (HAcr) is an O,N-chelating ligand whose coordination chemistry toward group 13 M(III) ions has received little attention. The molecular structure of HAcr consists of a 2,3-disubstituted-8-hydroxyquinoline; thus, in order to compare 8-hydroxyquinoline (HQ), 2-methyl-8-hydroxyquinoline (HMeQ′), and 2,3-disubstituted-8-hydroxyquinoline (HAcr) for steric and/or electronic influence, HAcr chelating ability toward the Al(III), Ga(III), and In(III) triad has been investigated. Irrespective of the nature of M(III), only complexes containing two equivalents of deprotonated HAcr are obtained. This article describes the synthesis and characterization of different series of bis-chelated pentacoordinated (Acr)2MY (M = Al, Ga, In; Y = Cl, Br, I, NCS, N3) or (Acr)2MZ (M = Ga or In; HZ = C6H5OH, C6H13OC6H4OH, C6H5COOH, or C6H13OC6H4COOH) six-coordinate neutral (Acr)2In(acac) (H(acac) =acetylacetone), or ionic [(Acr)2In(N,N)][CF3SO3] (N,N = 2,2′-bipyridine or 1,10-phenanthroline) complexes. These results significantly contribute to elucidating the complexation capability of HAcr.
Surface-Enhanced Raman Scattering of Adsorbates

Lehrstuhl ftir Oberflilchenwissenschaft (IPkM), Heinrich-Heine-Universitiit Diisseldo4,t000 Diisseldorf, Germany This review concentretes on the electronic contribution to surface+nhanced Raman scattering (SERS). This socalled . chemicel efrect' is quantitatively separeted from classical electromagnetic enhancement. It proceeds by increesed electrorphoton coupling at an atomicelly rough surface and by temporary charge transfer to edsorbate orbitals. These . oo". pt ". roppo.ted by various experimental results. The model sccounb for the chemical specificity and vibrationel selectivity of SERS and (partty) for the 'SERS specificity' of vsrious metals.
A model for switching and hysteresis in ferroelectric ceramics

Abstract In ferroelectric ceramics every grain has an average polarization arising from the spontaneous polarization of all domains. Since the domain configuration is known in fine grained as well as in coarse grained perovskite ceramics the average polarization can be easily determined. An electric field can invert the average polarization by 180° if it exceeds a critical field strength E2crit. At fields above E2crit a new 90° domain wall being perpendicular to the regular 90° domain walls nucleates at the boundary of the grain. It traverses the grain driven by the external field and disappears at the opposite grain boundary where its energy is dissipated. This transient domain wall is highly mobile, because, on its passage through the grain it does not change the gross shape of the grain. The calculated values of the critical electric field and its temperature dependence are in good agreement with observations. In addition, the new domain wall is the origin of dielectric nonlinearities in ferroelectric .
Absorption and Mobility of Boron in Young Citrus Plants

Boron (B) deficiency is widespread in Brazilian citrus orchards and has been considered an important soil constraint to citrus yield. The aim of this work was to study B uptake and its mobility in young citrus trees, under different B statuses, in two rootstocks. The experiment was carried out in a greenhouse, with ‘Valencia’ sweet orange trees budded on Rangpur lime or Swingle citrumelo. The plants were grown in pots containing nutrient solutions under either adequate or deficient B supply. Plants with different B levels were transplanted into solution with adequate level of B, enriched in 10B in different stages of development (vegetative growth and fruiting). About 20 to 35% of B content in the new parts of orange tree came from plant reserves. Boron mobility within the plant was influenced by its nutritional status; that is, the longer the period was that the plants were grown under deficient supply, the smaller was the mobility. Boron concentration in the sweet orange trees on Swingle was higher than that on Rangpur, suggesting higher demand of swingle Citrumelo for B.