In this research, a conductive adhesive based on epoxy resin as the polymer matrix and silver‐coated copper powder and silver‐coated reduced graphene oxide as conductive fillers was synthesized. Graphene oxide was synthesized by modified Hummer's method. It was reduced and modified by silver powder. Copper particles were coated with silver using the electroless plating method. Finally, conductive nanocomposite adhesives were prepared using conductive fillers with different weight fractions. The structural properties of fillers were identified by Fourier‐transform infrared (FTIR) and induced coupled plasma (ICP) analysis and the morphology of the samples by scanning electron microscopy (SEM). Finally, conductive properties, lap shear strength, and thermal stability of adhesive were evaluated. The conductive adhesive prepared with optimized properties have 70% weight percentage silver‐coated copper powder and 1% weight percentage silver‐coated reduced graphene oxide. The bulk resistivity of the optimum sample was 1.6 × 10‐2 Ω.cm, and the lap shear strength was 7.10 MPa. Also, thermogravimetric analysis showed that the weight loss of adhesive decreased from 88.72% to 30.55% during heating, which showed the addition of fillers improves the thermal stability of adhesive. 相似文献
Cr/MgO(x)–CeO2(100?x) nanocatalysts were synthesized by a coprecipitation method and characterized by X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM), energy-dispersive x-ray (EDX) spectroscopy, diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) analysis. The effect of ceria addition on their physicochemical characteristics was investigated, and the results were correlated with their catalytic performance in oxidative dehydrogenation of ethane. A decrease in the size of the metal particles was found when adding a suitable content of ceria to the support. Crystalline Cr2O3 was not found in the calcined samples, indicating good dispersion of Cr species on the support. All samples showed nanosized particles with uniform morphology, with the best surface morphology for the Cr/MgO(50)–CeO2(50) sample, on which the particle distribution mainly lay in the range of 40–60 nm. Variation of the amount of Ce in the support led to an enhancement of the Cr6+/Cr3+ ratio, with the highest value for the Cr/MgO(50)–CeO2(50) sample. This catalyst effectively dehydrogenated ethane to ethylene with CO2 at 700 °C even after 5 h on-stream, giving 42.76 % ethylene yield.
Accreditation and Quality Assurance - The Reference Health Laboratory (RHL) of Iran is the national authority responsible for making policies and plans for providing quality laboratory services... 相似文献
Reduction of [P2N2]ZrCl2 (where [P2N2] = PhP(CH2SiMe2NSiMe2CH2)2PPh) with KC8 under argon generates the phosphorus phenyl bridged bimetallic complex where the bridging phenyl groups are formally reduced to bis(allyl) dianions. Similar reduction of [P2N2]NbCl caused the one-electron reduction of the phosphorus phenyl group to generate a cyclohexadienyl moiety via a C-C bond formation between the ipso carbons of the two phenyl groups. 相似文献
A global population increase and an improved standard of living are generally expected. To meet these demands, an increased
production of chemicals will be necessary while protecting human health and the environment. However, most current methods
of chemical production are unsustainable. New designs must result in plants that assure process and operator safety, the sustained
health of workers and the community, and the protection of the environment. Traditional safety precautions and process controls
minimize risk but cannot guarantee the prevention of accidents followed by serious consequences. Therefore, the general approach
to environmental and safety problems must be changed from reactive to proactive. One way is to further develop the concept
of inherent safety.
In this paper some methods for inherent safety evaluations are reviewed. The aim of the study is to analyze the different
tools available for inherent safety evaluation and identify the most important criteria in determining the inherent safety
of a process plant. A model is proposed to show the interactions of different factors on the inherent safety level of a process
and the model is illustrated by a case study. 相似文献
In this paper, we investigate the existence, uniqueness and asymptotic behavior of solutions to a nonhomogeneous second order difference inclusion of accretive type in Banach spaces. We develop new methods and significantly extend and improve some known results in the literature. Our conclusions are new even for Hilbert spaces. 相似文献
Pyruvic acid contains three different reactive positions: –COOH, ketone carbonyl and methyl groups. Correspondingly, pyruvic acid was applied as starting material in the modified Niementowski reaction and Aldol condensation using SBA-Pr-SO3H as an efficient nanocatalyst. Aldol condensation of pyruvic acid and oxindole provided a new oxindol-based carboxylic acid which was subsequently used in the Ugi four-component reaction. Moreover, through the modified Niementowski reaction of pyruvic acid, new derivatives of quiazoline were produced in the presence of SBA-Pr-SO3H. The obtained products are important due to their potentially biological active skeletons. 相似文献
In this study a simple and rapid sample preparation technique, homogeneous liquid–liquid extraction based on phase separation in the presence of a salt performed in a narrow‐bore tube, followed by GC‐flame ionization detection has been developed. In this work, sodium chloride and ACN were used as the salting‐out agent and water‐soluble extraction solvent, respectively. The homogeneous solution of water and ACN was broken by addition of the salt. Small volume of ACN was collected on top of the tube and the extracted analytes in the collected phase were determined. It has been successfully used for the analysis of five phthalate esters as model compounds in aqueous sample. Experimental parameters affecting the extraction efficiency such as kind and volume of the water‐soluble organic solvent, length and diameter of the tube, and pH of the sample solution were investigated. Under the optimal conditions, the LODs were between 0.02 and 0.7 μg/L and enrichment factors were in the range of 172–309. In addition, good linearity (between 1 and 5000 μg/L) and high precision on the base of RSD (<8%, C = 600 μg/L, n = 6) were achieved. 相似文献