本文针对专业型硕士在校学习时间短的问题,构建了基于"翻转课堂"的专业型硕士必修课程《高等分离工程》线上、线下混合式教学模式;探索了自主学习、小组合作学习、探究学习等多种学习方式混合对教学的影响.实践表明,混合式教学模式能充分利用互联网+教学平台中网络资源及教学平台功能,既可解决研究生课堂学习时间短的问题,又充分发挥研究生自主学习能力,有效提高课堂效率及教学效果.

提取紫甘薯中红色素初品作为碳源,在水热条件下制备,经过柱层析、 旋蒸、 过滤等方法纯化后即得发蓝色荧光的碳量子点,并对其性能进行了表征.透射电镜表明碳量子点尺寸在10 nm左右,紫外光谱表明碳量子点在277 nm处有一个较大的吸收峰,荧光光谱表明所制备的碳量子点在440 nm处具有独立于激发波长的发射峰,且具有稳定的荧光特性.此外考察了碳量子点对金属离子的响应性能,结果表明该碳量子点在选择性检测Fe3+方面具有潜在的应用价值.

The carbon quantum dots with bule fluorescence were prepared by hydrothermal method and followed by filtration, centrifugation, steaming and dialysis purification methods using sodium cyanate as carbon source and melamine as nitrogen dopant. Their properties were characterized. TEM showed that the size of the prepared nanoparticles was about 5 nm. UV-Vis spectroscopy showed that there were two absorption peaks for carbon quantum dots. Fluorescence spectroscopy showed that carbon quantum dots had an excitation-independent emission at 436 nm with good stability in concentrated salt solutions and alkaline solution. In addition, the response of carbon quantum dots to the different pH of acidic solutions was investigated. The results showed that the carbon quantum dots had potential application value for the preparation of acid sensors.

本文总结了湖南农业大学应用化学专业在综合改革方面的探索与实践.以人才培养模式的改革为契机,对如何将农业院校应用化学类专业办出自己的特色进行了探索,开展了包括:调整专业人才培养定位、人才培养方案修订及人才培养模式的改革等工作;微调了专业口径,设置了专业方向;形成了特色较为鲜明的人才培养模式;取得了较好的改革成效.

在分析现有课程教学体系及实践环节存在的问题基础上,针对目前应用化学专业课程体系现状,对课程体系、实践环节进行顶层设计,提出并构建了农业院校应用化学专业一体化课程体系综合改革方案.实践表明,该课程体系的构建显著提高了教学效果,有利于学生科学素质和创新精神的培养.

如果不合理处理化学废弃物,不仅会污染自然环境,还会带来很多安全隐患.本文就目前农业院校基础化学实验废弃物处置面临的一系列问题及如何有效的处理化学废弃物进行了探讨.

农业院校开放基础化学实验室担负着全校农、林、理工科类学生的化学实验,实验室开放有利于解决学生人数多和教学资源有限之间的矛盾.因此,实验室开放势在必行,但是,要使实验室开放顺利进行,也是困难重重,本文就农业院校基础化学实验室开放存在的一系列问题以及如何解决这些问题进行探讨.

以吡咯(Pyrrole)为印迹分子,甲基丙烯酸(MAA)、4-乙烯基吡啶(4-Vp)、丙烯酰胺(AM)三种物质分别作为功能单体,运用密度泛函理论的M062X泛函,在6-31+G(d,p)基组下,模拟吡咯印迹分子与甲基丙烯酸、4-乙烯基吡啶、丙烯酰胺三种功能单体分子印迹聚合物自组装体系的构型,找到功能单体与模板分子结合所形成的复合物最优构型,并计算其结合能,并通过RDG函数的等值面分析来展现功能单体和吡咯分子弱相互作用类型.模拟计算结果表明,三种单体与MIP均是通过氢键的形式相互作用,而丙烯酰胺与吡咯之间相互作用最强,对MIP的识别能力最强,最适合作为制备吡咯分子印迹聚合物.

首次使用原位水解的方法成功制备了聚丙烯/二氧化硅(PP/SiO2)纳滤膜,在PP膜表面形成了一层致密的SiO2纳米聚合层,同时在膜的截面形成了由SiO2连接而成的提供离子传输的通道;该膜制备成本低,制备工艺简单环保,相较于Nafion115膜具有非常优异的防水迁移性能和较好的离子选择透过性,具有较好的充放电循环性能,在50 mA/cm2电流密度下,充放电循环40圈后,库伦效率及能量效率分别保持在94.5％和75.4％.

Extracting condition, composition, physicochemical property and antioxidant activity of polysaccharide which was extracted and purified from orange peel were investigated. Polysaccharide from orange peel was extracted using ultrasonic, and optimum extracting conditions of polysaccharide from orange peel with ultrasonic were studied by one-factor-at-a-time method and orthogonal experiments. The crude polysaccharide was purified by eliminating proteins with chloroform:n-butanol (5:1, V:V), concentrating, precipitating with cold ethanol and vacuum freeze drying. The composition of polysaccharide which was extracted and purified from orange peel was analyzed by employing ion chromatography. The physicochemical property and antioxidant activity of purified polysaccharide were measured. Results showed that purified polysaccharide from orange peel was composed of three kinds of monosaccharide, that was rhamnose, glucose and galacturonic acid. The physicochemical properties of purified polysaccharide from orange peel was soluble in water, slightly soluble in 95% ethanol, insoluble in ether, acetone, the content of ash was 0. 1191%, the content of protein was 0. 15 mg/g. The radical scavenging activity including DPPH radicals and O-2 radicals, and the total antioxidant activity were performed for raw polysaccharides and purified polysaccharides. Antioxidant capacity of polysaccharide from orange peel was below ascorbic acid (Vc) and 2,6-di-tert-butyl-p-cresol (BHT), while raw polysaccharide antioxidant capacity was better than purified polysaccharide.

Phytohormones, being a series of trace organic compounds synthesized in plants and playing important roles in plant growth at their low concentration, have been extensively studied in recent years.The ultrasensitive and in-situ detection of phytohormones remains an important scientific field in the plant research.In many existed detection methods, the electrochemical method has been acclaimed as a result of its excellent performance of high sensitivity and dynamic monitoring.In this review, we briefly introduce the recent advances in electrochemical sensing of phytohormones, including electrochemical biosensing, direct electrochemical sensing, photoelectronchemical sensing, and molecularly imprinted electrochemical sensing.Finally, the trends in electrochemical sensing of phytohormones are discussed.

The optimum extraction process condition of flavonoids from Veratrilla baillonii Franch by using microwave-assisted ethanol solvent method was studied, and the extraction of flavonoids were purified by using macroporous resin. Results showed that the best process conditions for the extraction were as follows: microwave power was 300 W, microwave time was 8 min, the ethanol concentration was 35%, the ratio of material to solvent was 1 :20, the yield of crude flavonoids was 32.19%, the content of flavonoids was 1.97%.AB-8 was the best resin.Under the dynamic condition, the sample liquid flow velocity was 2.00 mL/min, the eluent flow velocity was 2.00 mL/min.The contents of flavonoids were 20.17%.

The separation and purification process of flavonoids from tamarind shells by polyamide method was studied.The optimum resin and its optimum process conditions were determined by static experiments and dynamic experiments.The results indicated that polyamide was the best adsorption resin for flavonoids of tamarind shells .The optimum process conditions were that adsorption temperature was 20 ℃, adsorption time was 3 h, ethanol solvent concentration was 70%, desorption temperature was 30 ℃, desorption time was 4 h, the sample quality of resins was 30 g, elution volume was 2 BV, and elution times were three times.After purified, the contents of flavonoids from tamarind shells were increased from 12.93%to 31.00%.

The extracting technology of tamarind gum from the seed of tamarind gum was mainly studied.The single factor analysis and orthogonal test were designed to confirm the main factors and the optimum conditions .The results showed that the optimum conditions were pH =4.6, extraction time 20 min, solid:liquid ratio 1:35(w:V), and sedimentation time 4 h.Under these conditions , the extraction rate of pectin was 52.8%.The results showed that each performance index of the product was better than that of the national criterion.In addition, the DPPH and FRAP methods were used to measure the antioxidant activities of the product , and results showed that tamarind gum had higher antioxidative activity.

制备了一种碳纳米管-石墨烯纳米片复合膜修饰金电极的用于同时测定邻苯二酚和对苯二酚电化学传感器.并应用循环伏安法研究了邻苯二酚和对苯二酚在该电极上的电化学行为,邻苯二酚和对苯二酚的浓度检测采用差分脉冲伏安法,结果表明,碳纳米管-石墨烯纳米片复合膜极大的增强了邻苯二酚和对苯二酚的电催化活性.并在0.5～6.0×10-4mol/L浓度范围内与响应电流有良好的线性关系.邻苯二酚和对苯二酚的最低检测限分别是5.0×10-9和4.8×10-9 mol/L.该电化学传感器能用于实际样品中的酚类化合物的检测.

摘要: 制备了一种简单的聚谷氨酸修饰玻碳电极的用于检测甲基对硫磷的电化学传感器。 并应用循环伏安法研究了甲基对硫磷在该修饰电极上的氧化还原行为;甲基对硫磷的浓度检测采用差分脉冲伏安法,结果表明,甲基对硫磷在5.0×10-7~7.5×10-4 mol/L浓度范围与响应电流有良好的线性关系。 甲基对硫磷检测限(S/N=3)可达1.0×10-9 mol/L。 该法制备的传感器有望应用于实际样品中的甲基对硫磷的检测。

An electrochemical sensor was developed for the detection of methyl parathion(MP) based on electrodeposition of gold nanoparticles on a multi-walled carbonnanotubes modified the poly (thionine)(PTH) film that was electropolymerized on the glassy carbon electrode (GCE). Cyclic voltammetry (CV) was employed in the process of electrodeposition and electropolymerization. MP were determined using different pulse voltammetry (DPV). A highly linear response to MP in the concentration range from 5.0×10-8 to 5.0×10-4 mol/L was observed,with a correlation coefficient of 0.990 6, with a detection limit of 1.0×10-8 mol/L estimated at a signal-to-noise ratio of 3. The method has been applied to the analysis of MP in real samples.

制备了一种简单的聚谷氨酸修饰玻碳电极的用于检测甲基对硫磷的电化学传感器。并应用循环伏安法研究了甲基对硫磷在该修饰电极上的氧化还原行为;甲基对硫磷的浓度检测采用差分脉冲伏安法,结果表明,甲基对硫磷在5.0×10-7~7.5×10-4mol/L浓度范围与响应电流有良好的线性关系。甲基对硫磷检测限(S/N=3)可达1.0×10-9mol/L。该法制备的传感器有望应用于实际样品中的甲基对硫磷的检测。

制备了用于测定邻苯二酚（CAT）的石墨烯修饰电极,并应用循环伏安法研究了CAT在该修饰电极上的电化学行为;用差分脉冲伏安法研究了测试底液的pH值对该修饰电极性能的影响,结果表明,此修饰电极在含不同浓度CAT的PBS溶液（pH=7.0）中测定,响应电流与CAT浓度在5.0×10-8～5.6×10-4mol/L范围内有良好的线性关系,相关系数r=0.9919,检出限为6.68×10-9mol/L（S/N=3）。与其它几种修饰电极相比,石墨烯修饰电极制备简单、响应时间快、操作简便,稳定性和重现性良好,有应用价值。

采用电聚合的方法将普鲁士蓝(PB)聚合在玻碳电极表面,再将石墨烯修饰在 PB 上面,然后再采用电沉积的方法将 HAuCl4直接还原成纳米金粒子,沉积在石墨烯表面,最后将羊抗人 IgG 抗体直接固定于该修饰的玻碳电极表面,制备了用于人 IgG 抗原检测的非标记电化学免疫传感器.利用循环伏安法和交流阻抗研究了修饰电极表面的电化学特性,用差分脉冲伏安法对人 IgG 抗原进行了测定.实验表明,此免疫传感器在含不同浓度人 IgG 的 PBS 溶液(pH6.98)中测定,响应电流与人 IgG 浓度在5.55~455.5 ng/mL 范围内有良好的线性关系,其相关系数 r=0.9926,检测限为0.015 ng/mL(S/N=3).该免疫传感器具有制备简单、响应时间快(5 min)、稳定性好等特点