仪器分析实验课程教学设计——以高效液相色谱分析为例

结合大型分析仪器的特点及仪器分析实验课程的要求,文章以高效液相色谱分析为例,介绍了仪器分析实验课程在理论知识讲解、虚拟仿真预习、仪器认知过程、实验动手操作、结果分析讨论、全面过程考核方面进行的教学改革探索。教学中通过多种教学手段和循序渐进的课程设计,鼓励学生积极探索和发现,以期培养学生分析问题和解决问题的能力,提高学生的实践创新能力和专业水平。     

热分析实验条件选择对实验结果的影响

热分析技术应用越来越广泛,但由于仪器本身性能不同及操作者的原因,往往达不到预期的实验结果。本文根据长期的实验工作经验对热分析实验过程中对实验结果影响的因素进行了归纳,以便在实验过程中获得更好的实验结果。     

微课在仪器分析实验教学中应用与探讨

仪器分析实验是仪器分析课程教学中较为重要的组成部分。文章针对我校仪器分析实验授课过程中存在的几点问题进行分析,并将微课教学引入仪器分析实验教学,对微课在仪器分析实验教学中起到的作用和运行情况进行分析,探讨微课模式在仪器分析实验教学中的应用前景。     

微视频在仪器分析实验教学中应用的探索

针对仪器分析实验教学过程中存在的问题,如仪器套数少,学生兴趣不高,不了解仪器构造等。从而提供微视频作为教学资源,分析了微视频解决仪器分析实验存在问题的潜质,文章阐述了将微视频在仪器分析实验中的重要性,介绍了微视频的研究现状,论述了微视频在仪器分析实验中应用前景。     

金刚石钻头和金刚石锯片胎体耐磨性测试研究

在分析胎体磨损机理的基础上，自制了金刚石钻头和金刚石锯片胎体的耐磨性测试仪对金刚石钻头进行测试研究。介绍了该仪器的组成和工作原理及利用该仪器测试金刚石钻头的实验过程，分析了实验结果。实验结果表明，该仪器及测试方法具有较好的实用性和准确性。     

《仪器分析实验》线下线上混合式教学的探索与研究

仪器分析是高校化工、农学类、医学类和食品类等专业的一门重要专业基础课,仪器分析实验对培养学生的综合实验能力和分析测试能力有着重要意义。在实际教学过程中,仪器分析实验存在学时不足、大型仪器台套数不足、学生动手操作机会少等困境。本文以河南科技大学为例从教学大纲的制定、实验内容的确定、实验教学方式的改革以及实验教学设计改革等方面对仪器分析实验进行了线上线下混合式教学的改革探讨。     

微库仑分析的影响因素

微库仑分析法在实际应用过程中,准确度、灵敏度和自动化程度更高,也正因为如此,分析微量样品时,影响分析结果的因素也比较多。主要从仪器参数和实验现象两个方面来介绍各影响因素,从而得出对转化率的影响以及分析过程中常见问题的解决方式。     

化学分析结果准确度影响因素研究

化学分析是进行常量分析最主要的手段,在分析过程中由于客观的化学反应、化学试剂、操作仪器等,以及主观个人操作因素等都会影响分析结果的准确度。为了最大程度降低影响,要正确看待误差,注重实验反应的合理性、仪器选择及使用的正确性和规范性、试剂配制的正确性以及人员操作的规范性等,从而提高化学分析结果的准确度。     

基于“学生中心”理念的混合式教学研究——以食用醋总酸度的测定实验为例

食用醋总酸度的测定实验中,传统的单一线下讲授教学模式在仪器操作规范化和实验结果计算公式的推导中存在不足。本学院分析教学团队以“学生中心”,对食用醋总酸度的测定实验进行了线上线下混合式教学。通过线上学生自主观看教师录制的仪器操作视频,线下组织学生进行仪器操作比赛和分组讨论推导实验结果计算公式,引导学生开展自主、合作和探究性学习,激发了学生的学习热情,提高了学习效率和常规仪器操作的规范性。     

项目教学法在《仪器分析实验》教学中的设计与实施

改变了传统的实验教学模式,以培养学生创新创业能力为目标,将项目教学法引入《仪器分析实验》教学中来。以"大蒜素的提取及成分检测"为例,结合实际实验教学过程,阐述了项目教学法在《仪器分析实验》教学中的设计过程与实施情况。实践表明,项目教学法在仪器分析实验教学中的应用,调动了学生的积极性和主动性,激发了科研兴趣,为以后的本科毕业设计及科学研究打下了良好的基础。     

Antioxidant properties of deferoxamine

Deferoxamine, a natural trihydroxamate, was tested for its antioxidant properties. A significant antioxidant effect was detected in linoleic and linolenic acid suspensions, as well as in linoleic acid and fish oil emulsions. Its antioxidant activity was compared to that of butylated hydroxyanisole (BHA) and quercetin. In both emulsions and suspensions, the antioxidant effect of deferoxamine was in the same concentration range of BHA and quercetin. The antioxidant effect of deferoxamine in emulsions was lower than that of BHA. The effect of 0.770 mM deferoxamine in suspensions was the same as that of 0.555 mM BHA. Deferoxamine antioxidant activity in these systems was independent of its capability to bind iron. Inhibition of β-carotene degradation in linoleic acid-Tween 40 emulsion was lower than that of BHA. Deferoxamine inhibited the activity of soy lipoxygenase. The inhibition of lipoxygenase was reversible, but its mechanism is still unknown.     

选择测定水样中硫酸盐浓度方法的比较研究

文章就斗门自来水公司需要选择测定水样中硫酸盐浓度的方法进行了比较研究,比较对象为铬酸钡分光光度法的冷热两种方法。通过比较研究表明,铬酸钡分光光度冷法操作较热法简单,并且在测定含低浓度的硫酸盐的水样时,精密度也比热法高。该项研究有助于斗门自来水公司做出选择铬酸钡分光光度冷法作为测试水样中硫酸盐浓度方法的决策。     

循环流化床烟气脱硫吸收塔内结垢现象及机理分析

通过对循环流化床烟气脱硫吸收塔黏壁结垢现象进行分析,发现结垢主要发生在浆（水）喷嘴上方4～5 ｍ的环形过湿区域.同时研究了吸收塔结构和喷嘴尺寸,塔内流场和温度场分布以及运行工况对垢的形成过程的影响,并对垢进行了物理化学成分分析.结果表明,吸收塔内的垢无论是组成还是形成机理都与湿法的垢有很大不同,垢的形成以含湿灰的黏壁为主,其次为CaCO₃垢,这表明烟气中CO₂对垢的形成有很大影响.提出了防止循环流化床烟气脱硫结垢的技术措施.     

茭白废弃生物质苯酚液化及其产物树脂化制备胶黏剂

采用正交试验,考察了苯酚用量、催化剂用量、反应时间及反应温度对茭白废弃生物质液化效果的影响,并研究了该液化产物制备胶黏剂的影响因素。结果表明：茭白废弃生物质液化过程中,苯酚用量的影响最大,反应温度和反应时间次之,而催化剂用量的影响相对较弱,优化参数是苯酚用量为1：5,催化剂用量为7％,反应时间为90 min,反应温度为140℃,在此优化条件下,液化率为95．83％。胶黏剂制备过程中,茭白液化物与甲醛的质量比为1：1．8,高温缩聚反应温度为92℃较为合适。     

盐酸头孢甲肟的合成

以7-氨基头孢烷酸(7-ACA)为原料,通过两条路线对第三代头孢菌素——盐酸头孢甲肟的合成进行了系统考察。实验证明,7-ACA先在C-3位与5-巯基-1-甲基-1H-四氮唑(MMT)反应生成3-(1-甲基-1H-四氮唑-5-基)硫甲基-7-氨基头孢霉烷酸(7-ACT),再在C-7位和MAEM反应合成头孢甲肟的路线(摩尔收率为86%)优于先进行7-ACA的C-7位改造再进行C-3位改造的合成路线(摩尔收率为69%)。溶剂对反应的摩尔收率有较大影响,以二氯甲烷为溶剂时的反应效果最佳;同时证明超声能够显著缩短反应时间。     

USP－1型常温速干腻子的研制

对ＵＳＰ－１型常温速干腻子的生产工艺进行了研究。该腻子以不饱和聚酯为主要成分，采用复合促进、复合稳定体系和空心粉填料，固化剂采用自制的固化催干剂和固化稳定剂。对该腻子与国内外名牌腻子的性能作了比较。指出该腻子完全达到或超过Ｑ／ＪＧＮ０１－９５企业标准和日本工业标准ＪＩＳ－Ｋ５６５５（８０），性能与国际先进的ＧＧ牌腻子相当。     

Soybean lipoxygenase-promoted oxidation of free and esterified linoleic acid in the presence of deoxycholate

Lipoxygenase (EC 1.13.11.12) catalyzes the reaction between oxygen and polyunsaturated fatty acids to give fatty acid hydroperoxides. Recent work showed that soybean lipoxygenase 1 can oxidize diacylglycerols when deoxycholate is present in the reaction medium. Conditions were sought to maximize 1,3-dilinolein oxidation with a commercial soybean lipoxygenase preparation. It was found that dilinolein was oxidized most rapidly in a multicomponent buffer medium that contained 10 mM deoxycholate between pH 8 and 9. When dilinolein oxidation was conducted in the individual components of the multicomponent buffer, the oxidation rate decreased two- to threefold. Addition of 0.2 M NaCl to one of the components, Tricine buffer, caused a twofold increase in the oxidation rate, demonstrating that high ionic strength is a major factor promoting rapid oxidation in the multicomponent buffer. In the deoxycholate multicomponent buffer, the order of reactivity toward oxidation was monolinolein>methyl linoleate≈ linoleic acid>dilinolein. Competition experiments in which mixtures of the substrates were presented simultaneously to lipoxygenase in the presence of deoxycholate showed that linoleic acid was the most reactive substrate. When no surfactant was present or when the surfactant was Tween 20, linoleic acid was the most rapidly oxidized substrate. Overall, the results demonstrate that monolinolein and methyl linoleate are just as reactive, or more so, as linoleic acid to oxidation by lipoxygenase under specified reaction conditions. In competition experiments, linoleic acid oxidation predominates, probably because its free carboxyl functionality allows it to be preferentially bound to the active site of lipoxygenase.     

The kinetics of hammer milling of maize

The kinetics of breakage of maize were measured in a small laboratory hammer mill, with a rigid blade used as hammer. It was found that breakage was first-order, and that the primary breakage distributions were insensitive to mill conditions or moisture content of the material. The specific rates of breakage were dependent on particle size to approximately the third power; they increased as moisture content of the grain was reduced, showing that the drier material was more brittle; and a minimum rotation speed was necessary to get significant breakage. It appeared that material was thrown to the outer wall, so that only the ends of the hammer were effective, and a major part of fracture occurred by particles being thrown against the wall; an optimum loading exists for maximum breakage rates.     

聚烯烃弹性纤维XLA^TM的结构及其弹性表征

通过扫描电镜（SEM）、红外光谱（FT—IR）、力学试验和差示扫描量热法（DSC）等测试方法表征了聚烯烃弹性纤维XLA^TM的结构和弹性,对比分析了氨纶和XLA州纤维弹性的作用机理。XLA^TM纤维截面为圆矩形,表面较光滑;分子组成中不存在不饱和双键和非烃类物质,化学结构稳定;晶体中存在准六方晶和正交晶系两种晶型,结晶度为30％,比一般聚烯烃类纤维低很多;常温下处于高弹态,熔程较宽,为45～80℃;该纤维初始模量较氨纶高,在伸长率大于130％后拉伸强度比氨纶小;弹性回复率随伸长率的增加呈非线性下降趋势,塑性变形在180S内随回复停顿时间的延长而减小。     

Energy and force fields of pores and the effect of external factors on their configuration

The influence of a pore in a solid on the energy state of gas-phase molecules in terms of various models was revealed and the configuration of the relevant force fields was studied. It was shown that the energy predicted by these models for a gas molecule in the pore might be both higher and lower than its energy in the surroundings. The effect of the pore wall thickness on the configuration of the pore energy field was examined. Expressions were derived that make it possible to determine the force acting on gas molecules both in the pore and at each point of the surroundings. On this basis, the plot of the corresponding force field was constructed, a representation that leads to the conclusion that forces parallel to the pore axis act at the entrance to and the exit from the pore and that radial forces operate in the main body of the internal volume. The effect of an external solid surface on the pore force field was investigated. It was shown that this factor makes it possible to eliminate the energy threshold at the pore outlet under certain conditions, thereby opening new opportunities for using systems of this type in gas separation processes.