Growth,doping and characterization of epitaxial thin films and patterned structures of AlN,GaN, and AlxGa1−xN

Advancements in the doping of GaN and Al_xGa_1−xN thin films, and the growth of GaN and Al_xGa_1−xN structures on patterned heterostructure substrates via metalorganic vapor phase epitaxy are reported. The acceptor-type behavior of Mg-doped GaN films grown in N₂ diluents is presented. Net ionized impurity concentrations up to 8×10¹⁸ cm⁻³ and Hall mobilities up to ≈14 cm² V⁻¹ s⁻¹ were measured for Mg-doped films grown in N₂ in the as-grown condition. Donor and acceptor doping of Al_xGa_1−xN alloys was performed. Acceptor doping of Al_xGa_1−xN for x≤0.13 and donor doping for x≤0.58 were achieved for films deposited at 1100 °C. Lateral epitaxial overgrowth of GaN and Al_xGa_1−xN layers was investigated. The growth and coalescence of GaN and Al_xGa_1−xN stripes patterned in SiO₂ and/or SiN_x masks deposited on GaN, including aligned second lateral epitaxial overgrowth on initial laterally overgrown GaN layers, are discussed.     

Shaped Refractory Products-Packing, Marking, Transportation and Storage

1 Scope
This standard specifies the technical requirement of the packing, marking, transportation and storage of shaped refractory products.     

Sillimanite,Kyanite and Andalusite in China and Their Applications Part Ⅰ:Their Reserve,Distribution and Characteristics

Sillimanite, kyanite and andalusite areadvantageous natural refractory raw materials foraluminosilicate refractories to attain improved keyproperties. This paper are divided into two parts tointroduce their resource and technical characteristicin the first part, and their applications in refracto-ries in the second part to be succeeded. In this part,based on authors' knowledge and sources, informa-tion on their reserve, distribution, composition and     

Sillimanite,Kyanite and Andalusite in China and Their Applications Part I .Their Reserve,Distribution and Characteristics

Sillimanite,kyanite and andalusite are advantageous natural refractory raw materials for aluminosilicate refactories to attain improved key properties.This paper are divided into parts to introduce their resource and technical characteristic in the first part,and their applications in refractories in the second aprt to be succeeded.In this part,based on authors‘ knowledge and sources,information on their reserve,distribution,composition and characteristic is provided,to bring it to light that China is rich in the reserve of them,in particular andalusite.The sillimanite group minerals are characterized by their phase transformation to form primary mullite and secondary mullite when added in high alumina system,accompanied by volume expansion,which can be taken use to improve creep resistances and thermal shock resistance of the related refractories.     

Oxidative degradation kinetics of lycopene, lutein, and 9-cis and all-trans β-carotene

The thermal and oxidative degradation of carotenoids was studied in an oil model system to determine their relative stabilities and the major β-carotene isomers formed during the reaction. All-trans β-carotene, 9-cis β-carotene, lycopene, and lutein were heated in safflower seed oil at 75, 85, and 95°C for 24, 12, and 5 h, respectively. The major isomers formed during heating of β-carotene were 13-cis, 9-cis, and an unidentified cis isomer. The degradation kinetics for the carotenoids followed a first-order kinetic model. The rates of degradation were as follows: lycopene>all-trans β-carotene≈9-cis β-carotene>lutein. The values for the thermodynamic parameters indicate that a kinetic compensation effect exists between all of the carotenoids. These data suggest that lycopene was most susceptible to degradation and lutein had the greatest stability in the model system of the carotenoids tested. Furthermore, there was no significant difference in the rates of degradation for 9-cis and all-trans β-carotene under the experimental conditions.     

Excess Molar Volumes and Viscosities of Binary Mixtures of p-Xylene with Cyclohexane, n-Heptane, n-Octane, Sulfolane, N-Methyl-2-pyrrolidone and Acetic Acid at 303.15 K and 323.15 K and Atmospheric Pressure

Experimental data on density and viscosity at 303.15 K and 323.15 K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-S-pyrrolidone and acetic acid. From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.     

Effects of Zn, Cu, and K Promoters on the Structure and on the Reduction, Carburization, and Catalytic Behavior of Iron-Based Fischer–Tropsch Synthesis Catalysts

Zn, K, and Cu effects on the structure and surface area and on the reduction, carburization, and catalytic behavior of Fe–Zn and Fe oxides used as precursors to Fischer–Tropsch synthesis (FTS) catalysts, were examined using X-ray diffraction, kinetic studies of their reactions with H₂ or CO, and FTS reaction rate measurements. Fe₂O₃ precursors initially reduce to Fe₃O₄ and then to metallic Fe (in H₂) or to a mixture of Fe_2.5C and Fe₃C (in CO). Zn, present as ZnFe₂O₄, increases the surface area of precipitated oxide precursors by inhibiting sintering during thermal treatment and during activation in H₂/CO reactant mixtures, leading to higher FTS rates than on ZnO-free precursors. ZnFe₂O₄ species do not reduce to active FTS structures, but lead instead to the loss of active components; as a result, maximum FTS rates are achieved at intermediate Zn/Fe atomic ratios. Cu increases the rate of Fe₂O₃ reduction to Fe₃O₄ by providing H₂ dissociation sites. Potassium increases CO activation rates and increases the rate of carburization of Fe₃O₄. In this manner, Cu and K promote the nucleation of oxygen-deficient FeO _x species involved as intermediate inorganic structures in reduction and carburization of Fe₂O₃ and decrease the ultimate size of the Fe oxide and carbide structures formed during activation in synthesis gas. As a result, Cu and K increase FTS rates on catalysts formed from Fe–Zn oxide precursors. Cu increases CH₄ and the paraffin content in FTS products, but the additional presence of K inhibits these effects. Potassium titrates residual acid and hydrogenation sites and increases the olefin content and molecular weight of FTS products. K increases the rate of secondary water–gas shift reactions, while Cu increases the relative rate of oxygen removal as CO₂ instead of water after CO is dissociated in FTS elementary steps. Through these two different mechanisms, K and Cu both increase CO₂ selectivities during FTS reactions on catalysts based on Fe–Zn oxide precursors.     

Inhibition of β-Glucosidase and Esterase by Tannins from Betula, Salix, and Pinus Species

The reaction of tannin fractions isolated from the bark of Betula, Salix, and Pinus species with two enzymes, -glucosidase and esterase, was investigated. The influence of precipitation to the hydrolytic capacity of -glucosidase also was studied. All tannins studied precipitated -glucosidase and esterase, and moderate differences in the precipitating capacities of the tannins were observed. Interestingly, complex formation between -glucosidase and tannin did not markedly affect the activity of the enzyme. Therefore, complex formation during the insect/herbivore feeding does not necessarily change the defense activity of phenolic glycosides or decrease activity of digestive enzymes.     

What are batteries, fuel cells, and supercapacitors?

Electrochemical energy conversion devices are pervasive in our daily lives. Batteries, fuel cells and supercapacitors belong to the same family of energy conversion devices. They are all based on the fundamentals of electrochemical thermodynamics and kinetics. All three are needed to service the wide energy requirements of various devices and systems. Neither batteries, fuel cells nor electrochemical capacitors, by themselves, can serve all applications.     

Experimental Measurement and Correlation of the Solubility of Methyl-acetyl-naphthalene in n-Heptane,n-Octane,and n-Dodecane

1 INTRODUCTION 2-Methyl-6-acetylnaphthalene (2,6-MAN) is a type of white or pale yellow, powdery crystal, with a melting point of 332.15K. It is an important interme- diate[1] used for producing 2,6-naphthalene dicarbox- ylic acid (2,6-NDA), which has very extensive appli- cations in not only the light, electronic, and defense industries, but in many other areas. In particular, 2,6-NDA is an important monomer of liquid crystal polyester material (LCP) and polyethylene naphtha- lene-2…     

Measuring and Modeling Liquid–Liquid Equilibria for a Soybean Oil, Oleic Acid, Ethanol, and Water System

Vegetable oils can be deacidified by liquid–liquid extraction based on differences in polarity between triglycerides and fatty acids and differences in solubility. Information on the equilibrium between the phases of such systems is important for designing separation processes. The present paper reports experimental data for the extraction of fatty acid from soybean oil by (ethanol + water) as a mixed-solvent for system of soybean oil + oleic acid + ethanol + water at 30 °C at different water contents. The liquid–liquid equilibrium data of the systems were used to obtain interaction parameters in the universal quasi-chemical theory (UNIQUAC) activity coefficient model. These parameters can be used to predict equilibrium data of ternary and quaternary systems. The deviations between experimental and calculated compositions in both phases for each system using this model were calculated. The distribution coefficients and the selectivity factors of solvents for extraction of fatty acid from oil at 30 °C were calculated. Increasing of the water content as the co-solvent decreased the distribution coefficients and increased the selectivity factors of mixed-solvents, therefore considering the economical and practical aspects the optimum water content may be used for extracting oleic acid from soybean oil. We concluded that (ethanol + water) as a mixed-solvent can be used for extracting fatty acids from edible oils in a normal temperature.     

trans-2-Nonenal insect repellent,insecticide, and flavor compound in carrot roots,cell suspensions,and “hairy” root cultures

Astrans-2-nonenal (T2N) acts as an insect repellent, an insecticide, and a flavor compound, it would be desirable to manipulate its concentration in plants. Simple, rapid, and accurate trapping on cartridges of activated charcoal detected T2N in headspace over carrot roots and regenerants. Concentrations ranged from 0.07 to 0.43 ppm total volatiles over the homogenized roots of a range of European carrot cultivars with the following statistically significant differences: Long Chantenay > Sytan > Vertou > Touchon Prima. This suggests that the expression of T2N is determined genetically. Given the potential for genetic manipulation byin vitro techniques, the release of T2N and other terpenoids was monitored in carrot cell suspensions and in hairy root cultures of cv. Gelbe Rheinische. T2N concentrations were 6.23 ppm and 0.005 ppm, respectively, as compared with 0.15 ppm over the homogenized root of the same cultivar. Two terpenoids additional to T2N were detected from cell suspension cultures as compared with 14 from hairy root cultures. The ready detection in regenerants of this significant aldehyde indicates that its presence could be monitored in derivatives of otherin vitro manipulations.     

Fatty Acids,CD36, Thrombospondin-1, and CD47 in Glioblastoma: Together and/or Separately?

Glioblastoma (GBM) is one of the most aggressive tumors of the central nervous system, characterized by a wide range of inter- and intratumor heterogeneity. Accumulation of fatty acids (FA) metabolites was associated with a low survival rate in high-grade glioma patients. The diversity of brain lipids, especially polyunsaturated fatty acids (PUFAs), is greater than in all other organs and several classes of proteins, such as FA transport proteins (FATPs), and FA translocases are considered principal candidates for PUFAs transport through BBB and delivery of PUFAs to brain cells. Among these, the CD36 FA translocase promotes long-chain FA uptake as well as oxidated lipoproteins. Moreover, CD36 binds and recognizes thrombospondin-1 (TSP-1), an extracellular matrix protein that was shown to play a multifaceted role in cancer as part of the tumor microenvironment. Effects on tumor cells are mediated by TSP-1 through the interaction with CD36 as well as CD47, a member of the immunoglobulin superfamily. TSP-1/CD47 interactions have an important role in the modulation of glioma cell invasion and angiogenesis in GBM. Separately, FA, the two membrane receptors CD36, CD47, and their joint ligand TSP-1 all play a part in GBM pathogenesis. The last research has put in light their interconnection/interrelationship in order to exert a cumulative effect in the modulation of the GBM molecular network.     

Lithium Thiophosphate Glasses and Glass–Ceramics as Solid Electrolytes: Processing,Microstructure, and Properties

Lithium solid electrolytes are of major interest for solid-state batteries and electrochemical capacitors (ECs). Currently, the material selection space of liquid electrolytes is dominated by lithium salts paired with organics. Improved safety, as well as the need for higher temperature and high voltage operation, opens up opportunities for glass and ceramic alternatives in these important solid-state energy storage technologies. Lithium thiophosphates in the family x Li₂S + (1−x) P₂S₅ (mol fraction) possess room temperature ionic conductivities greater than 10⁻³(Ω-cm)^-1 in crystallized x = 0.70 (almost the highest in inorganic solid-state electrolytes). Within this review article, we address recent progress made in this class of material. We consider the role of densification on the Li-ion conductivity, as well as our recent data on the effect of densification on the electrochemical properties of the system. We cover the processing techniques of mechanical milling and pressure-forming, discuss microstructure, bulk versus surface conduction, and device integration. The systematic improvement in ionic conductivity with increased density suggests that bulk conduction dominates surface conduction and demonstrates that dense, rather than porous, lithium thiophosphate solid electrolytes are important in the design of solid-state batteries and ECs.