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排序方式: 共有1248条查询结果,搜索用时 163 毫秒
41.
Xin Zhong Luojing Xiang Sebastien Royer Sabine Valange Joel Barrault Hui Zhang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(7):970-977
BACKGROUND: A mesoporous alumina supported nanosized Fe2O3 was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe2O3‐Al2O3‐meso/H2O2 system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading. RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L?1. The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS). CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L?1, catalyst loading 0.3 g L?1, and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry 相似文献
42.
This article addresses the relation between day-specific experiences of job stressors and the pursuit of off-job activities. Following the limited-resources model of self-regulation, the authors proposed that job stressors and long working hours are negatively related to pursuit of sport activities after work because, after stressful days, employees have no resources left for initiating and persisting in effortful behaviors such as sport. Routines for off-job activities were hypothesized to be positively related to the pursuit of sport activities after work. Seventy-eight police employees completed a daily survey over 5 working days and indicated that they perceive sport to be highly useful for recovery. Random coefficient modeling showed that job stressors (particularly situational constraints) encountered on a specific day were negatively related to self-regulatory resources and to the amount of time spent on sport activities after work, whereas the relation with low-effort activities was positive. Thus, after a stressful day when an effective recovery activity such as sport is highly needed, persons tend to engage less in such an activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
43.
Highly Crystalline Films of PCPDTBT with Branched Side Chains by Solvent Vapor Crystallization: Influence on Opto‐Electronic Properties 下载免费PDF全文
44.
Radiation‐induced graft copolymerization of hydroxyethyl methacrylate with hydroxyethyl acrylate, acrylic acid or glycidyl methacrylate on ethylene tetrafluoroethylene (ETFE) films allow for tailor‐made synthesis of membranes for high and low temperature fuel cell applications. According to the operating temperatures proton conductivity may be achieved via doping with phosphoric acid or a two‐step sulfonation of the functional monomers. Fuel cell tests provide power densities and internal resistances, which indicate that the membranes are suitable for high and low temperature fuel cells. 相似文献
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46.
Jalal Poostforooshan Stephan Rennecke Manuel Gensch Sabine Beuermann Gabriella-Paula Brunotte Gerhard Ziegmann 《Aerosol science and technology》2014,48(10):1111-1122
This article presents a novel method to encapsulate gas-borne nanoparticles with a polymeric shell. This method implies heterogeneous condensation of monomer vapor around the surface of nanoparticles as nuclei and polymerization is then subsequently started by addition of NH3 as aerosol initiator. Ag and SiO2 nanoparticles were generated as inorganic core by spark discharge and nebulization, respectively, and glycidyl methacrylate (GMA) was used as organic monomer. The effect of several parameters, including vapor pressure of monomer and properties of inorganic core such as morphology, material, particle size, and production method on the thickness of polymeric shell and morphology of resulting nanocomposites has been investigated. The particle size distribution and morphology of the resulting core-shell nanoparticles have been studied via scanning mobility particle sizer (SMPS) and transmission electron microscope (TEM). Finally, the coating efficiency was determined by aerosol photoemission (APE) and the results show that monomer and polymer coating efficiency are 99% and 60%, respectively.
Copyright 2014 American Association for Aerosol Research 相似文献
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48.
Gracia Fahed Laurence Aoun Morgan Bou Zerdan Sabine Allam Maroun Bou Zerdan Youssef Bouferraa Hazem I. Assi 《International journal of molecular sciences》2022,23(2)
Metabolic syndrome (MetS) forms a cluster of metabolic dysregulations including insulin resistance, atherogenic dyslipidemia, central obesity, and hypertension. The pathogenesis of MetS encompasses multiple genetic and acquired entities that fall under the umbrella of insulin resistance and chronic low-grade inflammation. If left untreated, MetS is significantly associated with an increased risk of developing diabetes and cardiovascular diseases (CVDs). Given that CVDs constitute by far the leading cause of morbidity and mortality worldwide, it has become essential to investigate the role played by MetS in this context to reduce the heavy burden of the disease. As such, and while MetS relatively constitutes a novel clinical entity, the extent of research about the disease has been exponentially growing in the past few decades. However, many aspects of this clinical entity are still not completely understood, and many questions remain unanswered to date. In this review, we provide a historical background and highlight the epidemiology of MetS. We also discuss the current and latest knowledge about the histopathology and pathophysiology of the disease. Finally, we summarize the most recent updates about the management and the prevention of this clinical syndrome. 相似文献
49.
Werner Schroth Ronald Spitzner Mounifa M. Ezzat Monika Richter Sabine Freitag 《Advanced Synthesis \u0026amp; Catalysis》1990,332(2):148-160
On the Existence of 2-Imino-2H-1,3-thiazines The title compounds 2 are readily liberated from the 2-amino-1,3-thiazinium salts 1 by treatment with bases. Their stability depends sensitively on the substituents at the imino-N. The imino-N substituted 2a – i are isolable as well-defined coloured substances. Reaction of the 2 as well 1 with nucleophilic agents affords pyrimidine-2-thiones ( 4 , 9 – 11 , 16 – 18 ). In these ring transformations a nucleophilic addition at ring position 6 as primary reaction step is preferred. The imino-N unsubstituted representatives display a more complicated behaviour; the highly enhanced reactivity prevents or handicaps, respectively, any isolation. As exemplified in the base-induced ring-transformation of 1 m to the pyrimidine derivative 19 , these 2 are able to react as nucleophiles too, and versatile intermolecular self-reactions are increasingly favoured. 相似文献