Effects of a low amount of C on the phase transformations in the AlN–Al2O3 pseudo-binary system

The effects of a low amount of C on the phase transformations in the AlN–Al₂O₃ pseudo-binary system are reported in samples having an AlN content in mol% ranging between 44 and about 0. Various complementary experimental techniques were used to determine the nature of the phase equilibria. Carbon is embedded in the components of three eutectics as a function of the average chemical composition of the sample in AlN. In two of them, a component belonging to the quaternary system Al–O–N–C and having a wide composition range was found. Its X-ray and neutron diffraction spectra are well refined with a hexagonal crystalline structure.     

Effect of Si doping on the photocatalytic activity and photoelectrochemical property of TiO2 nanoparticles

Si-doped TiO₂ nanoparticles with anatase crystalline phase were prepared by a hydrothermal method using acetic acid as the solvent. Photoelectrochemical studies showed that the photocurrent value for the 15% Si-doped TiO₂ electrode (54.4 μA) was much higher than that of the pure TiO₂ electrode (16.7 μA). In addition, the 15% Si-doped TiO₂ nanoparticles displayed the highest photocatalytic activity under ultraviolet light irradiation. So doping suitable amount of Si in TiO₂ nanoparticles was profitable for transferring photogenerated electrons and inhibiting the recombination of photogenerated electrons and holes. As a result, the photocatalytic activity of TiO₂ nanoparticles was improved.     

Magnesium hydride based hydrogen chemical source: Development and application perspectives

In this paper, we studied the process of hydrolysis of magnesium hydride with water vapor and considered the possibility of creating a chemical source of hydrogen based on this process. To study the hydrolysis reaction of magnesium hydride powder at temperatures above 100 °C, an experimental setup with a quartz tube — a reactor 300 mm long — was designed. The mass and volume of a single powder load in a quartz reactor was 65 g and 130 ± 2 cm³, respectively. The length of the powder zone along the axis of the reactor was approximately 10 cm.Based on the data obtained during the experiment, it can be distinguished that the length of the reaction zone is greatest at the beginning and at the end of the hydrolysis process and is approximately 5–6 cm. In the middle of the hydrolysis process, for the time interval from 3000 to 5000 s, the reaction zone is the smallest - about 4–5 cm. The proposed design of the hydrolysis reactor and the experimental setup also made it possible to study the peculiarities of the hydrolysis of magnesium hydride powder with water vapor; magnesium, the composition of the reaction products and the controllability of the generation of a stream of hydrogen.     

Thermally treated wine retains antibacterial effects to food-born pathogens

Although cooking with wine and consumption of wine as a warm beverage is widespread, antibacterial effects of thermally treated wine have not been studied.We examined in vitro antibacterial activity of wine heated at 75 and 125 °C for 45 min against Salmonella enterica serovar Enteritidis and Escherichia coli. Their effects were compared with intact red wine, dealcoholized wine (DW) and dealcoholized wine reconstituted (RDW) with water to the initial volume. Samples were also analysed for their phenolics content, antioxidant capacity, resveratrol and ethanol content and pH.Total phenolics concentration and related antioxidative activity followed changes in samples volume, regardless of treatment type, while pH of all samples remained stable and ranged from 3.09 to 3.24.The order of the antibacterial activity of wine samples was: intact wine > heated at 75 °C > heated at 125 °C > DW > RDW.Antibacterial activity of the samples could not be related to their content of resveratrol as a single phenolics compound, antioxidative capacity or pH.Thermally treated wine under conditions applicable to food processing in everyday life, may be effective antibacterials in spite of significant heat-induced changes in their physical–chemical composition.     

Efficient blue organic light-emitting diodes based on triphenylimidazole substituted anthracene derivatives

A series of new blue emissive materials based on the conjugates of highly fluorescent diaryl anthracene and electron-transporting triphenylimidazole moieties: 2-(4-(anthracen-9-yl)phenyl)-1,4,5-triphenyl-1H-imidazole (ACBI), 2-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-1,4,5-triphenyl-1H-imidazole (1-NaCBI), 2-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-1,4,5-triphenyl-1H-imidazole (2-NaCBI) were designed and synthesized successfully. These materials exhibit good film-forming properties and excellent thermal stabilities. Meanwhile, the decreased π-conjugation in these compounds compared with phenanthroimidazole derivatives leads to obvious hypsochromic shift. To explore the electroluminescence properties of these materials, typical three-layer organic light-emitting devices were fabricated. With respect to the three layer device 2 using 1-NaCBI as the emitting layer, its maximum current efficiency reaches 3.06 cd A⁻¹ with Commission Internationale del’Eclairage (CIE) coordinates of (0.149, 0.092). More interestingly, sky blue doped device 5 based on 1-NaCBI achieved a maximum current efficiency of 15.53 cd A⁻¹ and a maximum external quantum efficiency of 8.15%, high EQE has been proved to be induced by the up-conversion of a triplet excited state.     

Two dication salts of ET: preparation and crystal structures of ET [FeII(CN)4(CO)2]

Single crystals of new dication bis(ethylenedithio)tetrathiafulvalene salts with [Fe^II(CN)₄(CO)₂]²⁻ were prepared electrochemically. Two kind crystals (A and B) with the same composition and different stacking patterns were derived from Na₂[Fe^II(CN)₄(CO)₂] and TBA₂[Fe^II(CN)₄(CO)₂], respectively.     

自吸式生物反应器放大方法研究进展

自吸式反应器具有操作简单、传质性能好等优点,特别是不需要空气压缩机等附件,节省了供气机械的投资和运行,在化学工程、环境工程、生化工程中得到了越来越广泛的应用。自吸式反应器内涉及气液两相体系,这种两相流体流动过程中的混合、传热和传质等过程非常复杂,仍有大量问题需要理论解释。文章对自吸式生物反应器的临界转速、吸气速率、功率、气含率和传质系数的理论模型,以及经验公式进行综述,并对其CFD模拟研究进展做出概括,对于自吸式反应器的放大应用有一定的参考价值。     

Effects of discharge mode and fuel treating temperature on the fuel utilization of direct carbon solid oxide fuel cell

Direct carbon solid oxide fuel cells (DC-SOFCs) with the novel perovskite La_0.3Sr_0.7Fe_0.7Ti_0.3O_3–δ (LSFT) electrodes are evaluated by using biochar derived from some one-time toothpicks made of wood as fuel in different discharging modes. The constant current (CC) mode and constant resistance (CR) mode are compared with same fuel cell configuration and fuel loading. The results show that the fuel discharged in CR mode possesses larger fuel utilization (39.7%) than that in CC mode (34.5%). The biochar fuels obtained from the wood pyrolysis in Ar atmosphere for 1 h at 400 °C, 500 °C, 600 °C and 700 °C present the efficiencies of fuel utilization are 26.3%, 34.1%, 38.6% and 39.6%, respectively. A special discharging mode is employed in this paper for DC-SOFC to test cell performance and improve fuel utilization simultaneously as well.     

Characterization and catalytic properties of MoO3–V2O5/Nb2O5 catalysts

The influence of molybdenum oxide on the dispersion of vanadium oxide supported on niobia was investigated. A series of MoO₃–V₂O₅/Nb₂O₅ catalysts with varying MoO₃ content ranging from 1% to 5% (w/w) with fixed V₂O₅ content were prepared by impregnation of previously prepared 5 wt% V₂O₅/Nb₂O₅ with requisite amounts of ammonium molybdate solution. X-ray diffraction patterns indicate the presence of β-(Nb,V)₂O₅ phase with the addition of MoO₃ up to a loading of 3 wt%. Temperature-programmed reduction (TPR) results suggest that the reducibility is decreasing with MoO₃ loading. The results of temperature programmed desorption (TPD) of ammonia suggest that the acidity of the catalysts increased with the addition of MoO₃. The catalytic properties of the catalysts in the ammoxidation of 3-picoline were correlated with the characterization data.