农林高校基础化学多层次课程体系和教学内容的改革与实践

以农林高校基础化学课程体系和教学内容改革为抓手,构建了农科特色鲜明的多层次课程体系,优化设计了教学内容,增强了教学的针对性,突出了学生个性的发展,为农科院校创新人才的培养奠定了重要的化学基础。     

酰胺基团对Gemini表面活性剂表面活性和聚集行为的影响

本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。     

钠在氯气中燃烧实验的改进

指出了现行高中化学教材中钠在氯气中燃烧实验的不足,详细介绍了改进后的实验装置及其实验方法,简化了氯气制备及其实验过程,保障了整个实验在封闭体系内进行,解决了钠在氯气中燃烧实验严重污染环境问题,从而培养了学生的环保意识。     

促进学生认识发展的“电离和离子反应”专题的单元整体教学研究

系统梳理了电离、离子反应专题的已有研究,分析了电离、离子反应内容对学生认识发展的作用,进而确立了化学1模块电离、离子反应专题的教学论问题并进行了阐述分析。在上述研究的基础上,设计了化学1模块电离、离子反应专题的单元整体教学,并进行了教学实践,取得了较好的教学效果。     

非线性多相催化动态模型的理论分析

本文讨论了吸附为非线性的多相催化的动态模型,用特征线方法对该模型进行了分析,求得了流出曲线的解析结果,指出了非线性对多相催化动态测量结果的影响,为速率参数及吸附参数在非线性条件下的动态测定给出了计算公式。     

声发射和激光拉曼研究镍氧化机制中的稀土元素效应

对纯镍及其表面离子注钇样品在1000℃空气中的恒温氧化和循环氧化行为进行了研究。用扫描电镜(SEM)和透射电镜(TEM)对氧化膜的表面形貌及结构进行了观测。研究表明离子注钇极大地提高了金属镍的抗氧化性能。此外,用声发射(AE)技术研究了氧化膜／基体界面上缺陷的分布情况,并用激光拉曼(Raman)谱对注钇引起的膜内应力变化进行了测量。结果表明,离子注钇降低了NiO氧化膜的生长速率,减小了表面NiO的晶粒尺寸,降低了膜内压应力水平。同时,离子注钇还减小了氧化膜／基体界面缺陷的平均尺寸和数目,因此,极大地提高了镍表面NiO氧化膜的粘附性和保护性。     

过氧化氢对8-氨基喹啉衍生物-铜和钴荧光体系的增敏作用及机理研究

本文介绍了新合成的8-氨基喹啉三系列衍生物,系统研究了它们与铜和钴的荧光反应,发现了试剂取代结构对其荧光性能的影响规律,试验了过氧化氢对铜、钴荧光体系的影响,发现了其增敏作用,探讨了增敏机理。     

无酶葡萄糖传感器

葡萄糖传感器在几十年的发展中取得了重大进展,经历了三代基于酶葡萄糖传感器之后,现已进入第四代无酶葡萄糖传感器的发展阶段.本文从基于酶和无酶两类介绍了不同葡萄糖传感器的测试原理,综述了近年来纳米材料在无酶电化学葡萄糖传感器方面应用的主要研究进展,对不同类别纳米材料的制备方法以及所构建传感器的灵敏度、选择性、检测范围和稳定性等进行了评述,分析了制约无酶葡萄糖传感器商业化应用的主要原因.其中,贵金属纳米材料主要讨论了铂、金和钯;过渡金属纳米材料主要讨论了镍、铜以及其氧化物;双金属纳米材料主要讨论了合金和复合物;碳纳米材料主要讨论了单壁(多壁)碳纳米管和石墨烯.此外,本文也对无酶葡萄糖传感器的发展方向和趋势进行了展望.     

微粒运动实验创新设计与改进

对微粒运动实验的仪器、用品作了改进,重新设计实验装置,使实验装置达到了小型化、封闭化、简洁化,实验达到了绿色环保要求,满足了大面积的学生探究实验操作使用,取得了良好的效益。     

分析化学实验课程教学大纲的标准化改造与构建

基于工程教育专业认证标准的要求,结合专业课程的特点,对我校制药工程专业的分析化学实验教学大纲进行了标准化改造。标准化的教学大纲更加突出了专业适用性,关联了教学要求与教学内容和考核评定,增加了考核量化指标与课程持续改进的方式,进一步规范了分析化学实验课程的教学。标准教学大纲的构建为实验教学活动提供了更加明确的指导,有利于缩小不同教师教学的差异性,保证了实验教学的质量,为建立可持续完善的工程类实验教学标准体系提供了具体参考。     

Spectrophotometric and gravimetric determination of sulfur in sebacate-base lubricants

Sulfur is determined in sebacate-base lubricants spectrophotometrically and gravimetrically. In the spectrophotometric method, a 0.2–0.3-g sample is treated with mixed acids, magnesium chloride is added, and the solution is evaporated to dryness. The sulfate is reduced to hydrogen sulfide by treatment with a mixture of hydriodic. hypophosphorous, and hydrochloric acids, and the hydrogen sulfide is distilled into ammonia solution. Lead citrate reagent is added and the brownish yellow color of lead sulfide sol is measured. An improved technique and apparatus for the distillation is described. In the gravimetric method, a 5-g sample is treated with mixed acids, antimony and tin are volatilized by treatment with hydrobromic acid, and sulfur is precipitated as barium sulfate. The recommended range of the spectrophotometric method is 0.005–0.15%,and that of the gravimetric method is 0.01–1% sulfur.     

用计算全息法检测卡塞格林系统主镜

为实现对卡塞格林光学系统中的非球面主镜表面面形的高精度检测,设计了一种二元位相型计算全息图(CGH)。介绍了工作原理,对CGH的相位模型参数的优化设计、衍射次级分离以及台阶位置与深度计算等关键问题进行了讨论。通过引入虚拟玻璃的概念快速建立非球面检测模型,针对卡塞格林系统主镜中心开孔的特点,通过加入同轴载波实现了衍射次级的完全分离,相比目前常用的倾斜载波方法简化了相位量化复杂度,数值仿真计算出了最优的台阶深度,降低了加工难度。给出了相应的设计方法及实例,研制投产了CGH。测试得到主镜面形的均方根误差为0.018λ,并与传统补偿器结果(RMS=0.019λ)进行对比,两者测试结果吻合,验证了该设计与检测方法的正确性,该设计方法简单快捷,适用于卡塞格林光学系统主镜面形检测。     

聚苯胺薄膜电极上示差脉冲伏安法可逆波理论研究

本文提出了聚苯胺(PANI)薄膜电极上示差脉冲伏安法可逆波理论,经验证理论和实验结果相符合.     

D241树脂分离纯化黄芩总黄酮的研究

本文研究了用241树脂分离纯化黄芩总黄酮的方法和工艺。实验结果表明：D241树脂对黄芩总黄酮的静态交换容量是77mg/ml树脂。在pH11.0、流速2.0BV/h、提取液中总黄酮浓度17.5mg/ml条件下，D241树脂对黄芩总黄酮的动态交换容量为43.8mg/ml。用60％甲醇作为黄芩总黄酮洗脱剂，在PH4.0、洗脱流速1.5BV/h条件下，4．5BV洗脱剂即可完全洗脱被D241树脂交换的黄芩总黄酮。与酸沉淀法相比较，经过除去果胶，总黄酮纯度由33．34％提高到74．9％，粗品收得率由11.52%降低至4.83%；经过D241树脂分离纯化，其纯度达到91.5%，产品收得率3.54%。     

A rapid solvent extraction method for the determination of caesium-137 in environmental materials

A solvent extraction method for the quantitative determination of caesium-137 in environmental samples is described. Caesium carrier is added to the ashed sample, which is dissolved with hydrochloric acid. The solution is filtered to remove any carbon and the pH is adjusted to 2.0. Sodium dodecylbenzene sulphonate is added and the extraction is done with phenol-nitrobenzene mixture. The organic phase is washed with EDTA solution and the caesium is stripped from the washed solvent with 6 M hydrochloric acid. The caesium is precipitated as caesium chlorostannate to ensure absolute decontamination from potassium-40. Recovery from standard solution is about 85% and from vegetation, rainwater and effluent samples about 80%. The method is applicable in the presence of large quantities of interfering ions, and decontamination factors for many nuclides are greater than 10³.     

On energy bounds derived from the conjugate eigenvalue problem

An upper bound for E₀, which has been derived from the conjugate eigenvalue problem by Hall, is discussed. It is emphasized that the bound is only guaranteed when V is negative-definite. An alternative bound is presented which is free from this restriction, and the underlying iterative procedure is given. Hall's result is generalized to admit internuclear distances, and the theory is illustrated by a one-dimensional system with delta-function potentials. Some disadvantages of the approach are mentioned.     

Behavior of Lβ2 visible satellites in gold around L1 threshold

The Au $L{\beta }_2$ visible satellites, $L{\beta }_2^{\prime }$ and $L{\beta }_2^{″}$ were measured around the $L_1$ absorption edge using a high-resolution Johann-type spectrometer at BL15XU, SPring-8. The relative intensities of the $L{\beta }_2^{\prime }$ and $L{\beta }_2^{″}$ satellites to that of the $L{\beta }_2$ line exhibit an abrupt jump at the $L_1$ threshold. The results suggest that the origin of the $L{\beta }_2$ satellites is mainly the $L_1$–$L_3{M}_{4,5}$ Coster–Kronig transitions.     

Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue

Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.