Synthesis of acicular α-Bi2O3 microcrystals by microwave-assisted hydrothermal method

ABSTRACT

Materials based on bismuth(III) oxide are candidate to be used in optical and electronic devices because of their properties such as a variable band gap, photoconductivity, photoluminescence, high refractive index, and dielectric permittivity. These properties are dependent of several factors, e.g., present phases and crystal morphology. The microwave-assisted hydrothermal method (MAH) is a fast and efficient approach of synthesis to obtain semiconductor powders. However, the synthesis of monoclinic bismuth oxide (α-Bi₂O₃) with acicular morphology by MAH was not found in literature. In this paper, microcrystals of acicular α-Bi₂O₃ (monophasic) were successfully obtained by MAH using a synthesis temperature of 80°C for 0.5?h. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron, and transmission electron microscopies showed the formation of a monoclinic structure (space group P21/c) with acicular morphology that grew along the [001] direction. The temperature and time necessary to synthetize acicular microcrystals were significantly lower than those found for acicular microcrystals obtained by conventional hydrothermal method.     

NMR investigation of atomic bonding properties in Al–Li alloys

It has been suggested that intrinsic ductile versus brittle properties of alloys be connected with bonding characters in some sense while there is no much proof. In this investigation, ²⁷Al isotropic metallic shifts of Al–Li solid solutions were measured by ²⁷Al NMR spectroscopy. Previously observed anomalous elastic properties upon Li alloying were found to be closely related to ²⁷Al metallic shifts which were associated with s electron density of states at the Fermi level on Al sites. This result is relevant for better understanding of electronic origin of solid solution strengthening mechanisms in Al–Li alloys from the point of view of electronic structure.     

化学激发作用对磨细矿渣活性的影响

通过试验,探讨了化学激发作用对磨细矿渣活性的影响,采用CaO,NaOH,KAl(SO4)2·12H2O,Na2SO4四种化学试剂,主要研究了不同化学试剂对磨细矿渣不同的试验效果,为类似研究奠定了基础。     

煤基活性炭制备中化学添加剂的应用对比

化学添加剂对煤制活性炭的制备过程具有一定的控制作用。以唐山矿长焰煤为研究对象,按照不同比例加入了不同量的ZnCl2和KOH,研究了炭化过程中化学添加剂对煤挥发性、煤产物微晶结构以及活化程度的影响,为煤基活性炭制备工艺的优化提供了参考。     

Standardization of Nanoparticle Characterization: Methods for Testing Properties,Stability, and Functionality of Edible Nanoparticles

There has been a rapid increase in the fabrication of various kinds of edible nanoparticles for oral delivery of bioactive agents, such as those constructed from proteins, carbohydrates, lipids, and/or minerals. It is currently difficult to compare the relative advantages and disadvantages of different kinds of nanoparticle-based delivery systems because researchers use different analytical instruments and protocols to characterize them. In this paper, we briefly review the various analytical methods available for characterizing the properties of edible nanoparticles, such as composition, morphology, size, charge, physical state, and stability. This information is then used to propose a number of standardized protocols for characterizing nanoparticle properties, for evaluating their stability to environmental stresses, and for predicting their biological fate. Implementation of these protocols would facilitate comparison of the performance of nanoparticles under standardized conditions, which would facilitate the rational selection of nanoparticle-based delivery systems for different applications in the food, health care, and pharmaceutical industries.     

Electrochemical performance of reduced graphene oxide in Spiro‐(1, 1')‐bipyrrolidinium tetrafluoroborate electrolyte

This paper investigates the relationship between structure and electrochemical performance of reduced graphene oxide (RGO) prepared via heat treatment and chemical reduction method. Structure and morphology of RGO was characterized by means of Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction and Brunauer–Emmett–Teller. Electrochemical performance of RGO electrode supercapacitor was investigated in the organic electrolyte by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance. The results show heat treatment RGO has high graphitization degree, less surface oxygen‐containing groups, good charge–discharge efficiency and stable life cycle. The chemical reduced RGO has single‐graphene structure, high specific surface area, high specific capacitance and low internal resistance. The ascorbic acid reduction RGO exhibits good comprehensive electrochemical performance: Its specific capacitance was 220.7 F g^?1, internal resistance was 3.0 Ω and charge–discharge efficiency was 97.0% after 2000 cycles of charging/discharging tests. Copyright © 2016 John Wiley & Sons, Ltd.     

煤化工工艺技术发展趋势浅析

本文主要针对目前煤中低温干馏的工艺技术现状,从节能降耗、资源充分利用角度探讨洁净型煤化工工艺技术的发展趋势,对煤的中低温热解技术的选择具有重要意义。     

Recovery of Hydroxytyrosol Rich Extract from Two‐Phase Chemlali Olive Pomace by Chemical Treatment

Abstract: A very simple method is proposed to produce hydroxytyrosol, a commercially unavailable compound with well‐known biological properties which justify a potential commercial application. The 2‐phase Chemlali olive pomace is selected as substrate for chemical treatment. Different conditions of chemical treatment, including concentration of acid and alkaline solutions, time and temperature, were assayed. A high amount of hydroxytyrosol (1360 mg/kg of fresh 2‐phase olive pomace) was obtained using water bath after treatment at 80 °C for 90 min with 1 M of H₃PO₄. However, treatment of 2‐phase Chemlali olive pomace using autoclave apparatus could produce a large amount of hydroxytyrosol (1993.60 and 1515.88 mg/kg of fresh alperujo, 1 M acid and basic catalyst, respectively). By taking into consideration practical and economic aspects, acid‐catalyzed treatment was more effective using autoclave conditions, whereas the alkali catalyzed conditions were not very suitable. This study could provide useful information for industry to produce the potentially bioactive compound. Practical Application: The 2‐phase Chemlali olive pomace is selected as substrate for chemical treatment. Treatment of “alperujo” using water bath or autoclave apparatus was carried out. A high amount of hydroxytyrosol was obtained using autoclave apparatus.     

Heat and mass transfer characteristics of radiative hybrid nanofluid flow over a stretching sheet with chemical reaction

Unsteady magnetohydrodynamic heat and mass transfer analysis of hybrid nanoliquid flow over a stretching surface with chemical reaction, suction, slip effects, and thermal radiation is analyzed in this study. A combination of alumina (Al₂O₃) and titanium oxide (TiO₂) nanoparticles are taken as hybrid nanoparticles and water is considered as the basefluid. Using the similarity transformation method, the governing equations are changed into a system of ordinary differential equations. These equations together with boundary conditions are numerically evaluated by using the Finite element method. The influence of various pertinent parameters on the profiles of fluids concentration, temperature, and velocity is calculated and the outcomes are plotted through graphs. The values of nondimensional rates of heat transfer, mass transfer, and velocity are also analyzed and the results are depicted in tables. Temperature sketches of hybrid nanoliquid intensified in both the steady and unsteady cases as the volume fraction of both nanoparticles rises.