排序方式: 共有145条查询结果,搜索用时 15 毫秒
91.
Hassen Khazri Ibtissem Ghorbel‐Abid Sihem Ben Hassine Sylvie Chevolleau Laurent Debrauwer Rafik Kalfat Malika Trabelsi‐Ayadi 《Journal of separation science》2019,42(9):1710-1716
In this work, clay‐Na particles are used as the adsorbent for the solid‐phase extraction of acidic compounds. The novel sorbent under study is based on high‐specific surface area, cation‐exchange capacity designed specifically to offer ion‐exchange properties with the goal being to selectively extract a group of acidic compounds. The effects of the extraction parameters including extraction elution solvent, sample volume and pH. In optimum conditions, the repeatability for one fiber (n = 3), expressed as % relative standard deviation, was between 0.3 and 4.3% for the acid compounds. The detection limits for the studied acidic compounds were between 0.1–0.6 μg/L. The developed method offers the advantages of being simple to use and having a low cost of equipment. 相似文献
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Evan W. Muller Alfred A. Burney-Allen Jessica Shaw David L. Wheeler Volodimyr Duzhko Malika Jeffries-EL 《Journal of polymer science. Part A, Polymer chemistry》2020,58(9):1299-1310
The use of direct C H arylation cross-coupling polymerization was evaluated for the synthesis of donor–acceptor conjugated co-polymers using the novel donor 1,6-didecylnaphtho[1,2-b:5,6-b']difuran and either thieno[3,4-c]pyrrole-4,6-dione (TPD) or 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) as the acceptor. Thiophene and furan moieties were used to flank the DPP group and the impact of these heterocycles on the polymers' properties was evaluated. The alkyl chains on the diketopyrrolopyrrole monomers were varied to engineer the solubility and morphology of the materials. All of the polymers have similar optoelectronic properties with narrow optical band gaps around 1.3 eV, which is ideal for solar energy harvesting. Unfortunately, these polymers also had high-lying highest occupied molecular orbital levels of −4.8 to −5.1, and as a result bulk-heterojunction photovoltaic cells fabricated using the soluble fullerene derivative PC71BM as the electron-acceptor and these polymers as donor materials exhibited poor performance due to limited Voc values. An examination of the films from these blends indicates that film-thickness and morphology were also a major hindrance to performance and a potential point of improvement for future materials. 相似文献
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Photocatalytic Degradation of Oxytetracycline in Aqueous Solutions with TiO2 in Suspension and Prediction by Artificial Neural Networks 下载免费PDF全文
In this study, the photocatalytic degradation of oxytetracycline (OTC) in aqueous solutions has been studied under different conditions such as initial pollutant concentrations, amount of catalyst, and pH of the solution. Experimental results showed that photocatalysis was clearly the predominant process in the pollutant degradation, since OTC adsorption on the catalyst and photolysis are negligible. The optimal TiO2 concentration for OTC degradation was found to be 1.0 g/L. The apparent rate constant decreased, and the initial degradation rate increased with increasing initial OTC concentration with the other parameters kept unchanged. Subsequently, data obtained from photocatalytic degradation were used for training the artificial neural networks (ANN). The Levenberg–Marquardt algorithm, log sigmoid function in the hidden layer, and the linear activation function in the output layer were used. The optimized ANN structure was four neurons at the input layer, eighteen neurons at the hidden layer, and one neuron at the output layer. The application of 18 hidden neurons allowed to obtain the best values for R2 and the mean squared error, 0.99751 and 7.504e–04, respectively, showing the relevance of the training, and hence the network can be used for final prediction of photocatalytic degradation of OTC with suspended TiO2. 相似文献
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Samia Bouzroura Lamouri Hammal Fadila Balegroune Malika Hamadène Sophie Poulain 《合成通讯》2013,43(3):448-455
High‐yielding syntheses of an unpublished series of 2‐thioxo‐imidazolidin‐4‐ones 6 bearing an N‐ethoxycarbonyl and amidyl moieties an N1 and C5, respectively, are reported. These derivatives were obtained by intramolecular cyclization of 3‐ethylhydrazinoacetate 3,4‐dihydro maleimides 4 in the presence of ethyl or phenylisothiocyanate 2 under neutral conditions. 相似文献
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Malika Ibrahim-Ouali Marie-Eve Sinibaldi Yves Troin Daniel Gardette Jean-Claude Gramain 《合成通讯》2013,43(11):1827-1848
The synthesis of original allenic lactams 2 and allenic esters 5 is presented and their Michael condensation with N-benzylaniline described. 相似文献
99.
Noemí Echegaray Mirian Pateiro Paulo E. S. Munekata Jos M. Lorenzo Zakariya Chabani Mohamed A. Farag Rubn Domínguez 《Molecules (Basel, Switzerland)》2021,26(13)
At present, a wide variety of analytical methods is available to measure antioxidant capacity. However, this great diversity is not reflected in the analysis of meat and meat products, as there are a limited number of studies on determining this parameter in this complex food matrix. Despite this, and due to the interest in antioxidants that prevent oxidation reactions, the identification of antioxidants in meat and meat products is of special importance to the meat industry. For this reason, this review compiled the main antioxidant capacity assays employed in meat and meat products, to date, describing their foundations, and showing both their advantages and limitations. This review also looked at the different applications of antioxidant properties in meat and meat products. In this sense, the suitability of using these methodologies has been demonstrated in different investigations related to these foods. 相似文献
100.
Mihaela C. Iovu Malika Jeffries‐El Rui Zhang Tomasz Kowalewski 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1991-2000
Grignard Metathesis polymerization (GRIM) for the synthesis of regioregular poly(3‐alkylthiophenes) proceeds via a “living” chain growth mechanism. Due to the “living” nature of this polymerization regioregular poly(3‐alkylthiophenes) with predetermined molecular weight, narrow molecular weight distributions and desired chain end functionality are now readily available. Allyl terminated poly(3‐hexylthiophene) was successfully used as a precursor for the synthesis of di‐block copolymers containing polystyrene. The addition of “living” poly(styryl)lithium to the allyl terminated regioregular poly(3‐hexylthiophene) generated the di‐block copolymer. Poly(3‐hexylthiophene)‐b‐polystyrene was also synthesized by atom transfer radical polymerization. Integration of poly(3‐hexylthiophene) in di‐block copolymers with polystyrene leads to the formation of nanowire morphology and self‐ordered conducting nanostructured materials. 相似文献