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61.
基于科学哲学和语言学理论,强调化学学科中的三重表征的话语意义,旨在帮助学生将头脑中的三重表征思维用语言科学地表达出来并进行社会性交往。在明确三重表征与话语的关系的基础上,借助于相关教学片段,对三重表征的话语意义(语法学、语义学和语用学意义)进行探析,将宏观微观符号表征中各自的语言内部联系以及彼此间的话语表达关系解构出来,从而全面提升学生在建构、关联及转换表征过程中的交往效率。最后针对相关教学问题,提出了3条教学策略。 相似文献
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Aliona Ghendov-Mosanu Daniela Cojocari Greta Balan Antoanela Patras Ildiko Lung Maria-Loredana Soran Ocsana Opri Elena Cristea Rodica Sturza 《Molecules (Basel, Switzerland)》2022,27(5)
The article focuses on the optimization of the extraction process of biologically active compounds (BAC) from grape marc—a by-product of the wine industry. The influence of temperature, specifically 30 °C, 45 °C and 65 °C, and ethanol concentration in solutions, specifically 0–96% (v/v) on the extraction yield of polyphenols, flavonoids, tannins and anthocyanins, were investigated. The composition of individual polyphenols, anthocyanins and organic acids, antioxidant activity (DPPH and ABTS) and CIELab chromatic characteristics of the grape marc extracts (GME), were characterized. The microbiostatic and microbicidal effects in direct contact of GME with pathogenic microorganisms, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, were determined in vitro. The influence of extraction parameters on the total polyphenol content (TPC), total flavonoid content (TFC), tannin content (TC), total anthocyanin content (TAC) and their interdependencies were studied using information analysis. A mathematical model was developed on cubic spline functions. The analysis of individual compounds showed the presence of a wide range of flavonoids (procyanidin B2, procyanidin B1, hyperoside and quercetin), flavones (catechin), hydroxybenzoic acid derivatives (gallic, protocatechuic, p-hydroxybenzoic acids, m-hydroxybenzoic acid, syringic acid), hydroxycinic acid derivatives and ferulic acid methyl ester. The malvidol-3-glucoside was the main anthocyanin identified in the extract. A high amount of tartaric acid was also found. GME showed significant antimicrobial activity against Gram-positive bacteria and lower activity against Gram-negative bacteria. 相似文献
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Fares Zouaoui Saliha Bourouina-Bacha Mustapha Bourouina Nadia Zine Abdelhamid Errachid Nicole Jaffrezic-Renault 《Molecules (Basel, Switzerland)》2022,27(2)
The massive and careless use of glyphosate (GLY) in agricultural production raises many questions regarding environmental pollution and health risks, it is then important to develop simple methods to detect it. Electrochemical impedance spectroscopy (EIS) is an effective analytical tool for characterizing properties at the electrode/electrolyte interface. It is useful as an analytical procedure, but it can also help in the interpretation of the involved fundamental electrochemical and electronic processes. In this study, the impedance data obtained experimentally for a microsensor based on molecularly imprinted chitosan graft on 4-aminophenylacetic acid for the detection of glyphosate was analyzed using an exact mathematical model based on physical theories. The procedure for modeling experimental responses is well explained. The analysis of the observed impedance response leads to estimations of the microscopic parameters linked to the faradic and capacitive current. The interaction of glyphosate molecules with the imprinted sites of the CS-MIPs film is observed in the high frequency range. The relative variation of the charge transfer resistance is proportional to the log of the concentration of glyphosate. The capacitance decreases as the concentration of glyphosate increases, which is explained by the discharging of the charged imprinted sites when the glyphosate molecule interacts with the imprinted sites through electrostatic interactions. The phenomenon of adsorption of the ions in the CMA film is observed in the low frequency range, this phenomenon being balanced by the electrostatic interaction of glyphosate with the imprinted sites in the CS-MIPs film. 相似文献
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以种植果树为例,根据果树种植的客观规律,引进折扣因子δ=U-α,给出了通过确定投资合同期使利润达到最大的数学模型,并进行了讨论和推广. 相似文献
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数学建模融入微积分教学单元 总被引:1,自引:1,他引:0
本文是教育部项目的子课题中期报告中样板单元,针对打假的机理问题设计了数学建模融入微积分的一个教学单元,文中详细地给出了单元的全文、讲授和实践(或计划讲授和实践)的学时的安排、师生的反映、体会和建议. 相似文献
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