“互联网+”背景下基础化学原理实验在线学习与考试系统的开发与实践

在移动互联网的飞速发展与智能手机等移动终端日趋普及的情况下,设计开发了基于移动端的基础化学原理实验在线学习与考试系统。该系统包括化学实验室安全教育与考试、实验基础理论学习、试题库资源、移动端在线考试、成绩管理和统计分析等五大功能。该系统的开发建设顺应了"互联网+教育"的发展趋势,有利于学生自主学习,节约考试资源。     

计算机在大学化学实验教学中的应用

以悉尼大学一年级化学实验在线预习系统为例 ,介绍网上预习和在线测试的思想 ,通过对测试结果的分析统计 ,教师和学生可以准确了解实验难点和预习情况 ,从而有效地利用实验时间 ,达到好的教学效果     

化学信息学网络考试系统的构建

在WindowsNT 4 .0服务器建立化学信息学的Access试题数据库 ,使用ASP编写网络考试系统 ,供学生在Internet上使用浏览器进行在线考试。该系统安全可靠、应用范围广 ,是发展远程教育的重要工具     

高校实验室安全教育在线资源调查研究*

对国内高校实验室安全教育在线资源现状进行调研。调查结果表明:在线资源主要有慕课、虚拟仿真实验及安全教育考试系统。因此,在安全教育过程中,可充分利用现有线上资源,弥补线下教学因时间有限、容量有限导致的不足,从而提高安全教育实效。线上、线下安全教育如何有机结合从而最大限度地发挥其在高校安全教育中的作用,仍需不断探索。     

普通高中学业水平化学实验考试的现状、反思与建议

以江苏省普通高中学业水平化学实验考试为例,对高中化学实验考试的现状进行反思,分析实验考试在组织、设计、实施以及效度上存在的问题,对促进学生创新精神和实践能力发展的实验考试设计提出一些建议。     

石油工程专业“油田化学”课程教学改革及实践效果分析

分析了石油工程专业“油田化学”课程的教学现状,认为非化学专业学生的化学基础、学习主动性和课程教学考试方式是影响学生能力培养的主要原因。通过创新基础理论的教学方法,将能力培养贯穿于教学的全过程,并将课堂讨论和分析能力纳入考试的总评成绩。量化数据和问卷调查分析结果表明,教学改革措施能有效提高学生的学习积极性和分析问题能力,并能较为准确地评估学生的学习效果,若要进一步提高学生的学习效果,仍需对课程进行系统规划并加强教学与实验环节的结合。     

趣味化学实验在初中化学教学中的应用

化学教学离不开实验,趣味性化学小实验,简便易行、安全有趣,实验现象明显,使学生对化学产生强烈的求知欲,从而激发学生的化学学习兴趣.利用化学实验的趣味性,激发学生的化学学习兴趣,使学生有常新常乐的感觉.     

无机化学与化学分析课程在线期末考试的探索与实践

为应对新型冠状病毒肺炎疫情,在线期末考试的探索与实践成为一个新的研究热点。本文以"无机化学与化学分析"课程为例,面对疫情期间的特殊性,从在线考试设计、在线考试准备、考试实施和学生反馈等方面对于在线考试进行了多维度的介绍,总结了经验并进行了反思,提出了切实可行的考试流程,为高校开展学生较多的公共基础课的在线考试提供了参考和借鉴。     

加强初三学生实验操作技能的训练

以往的初中化学考试基本以笔试形式、化学实验部分内容的考试,也是以书面形式考查认知领域的知识为主。1995年我市为了落实新教材课程标准的目标,发挥化学实验的教育、教学作用,全面提高学生的素质,在初三毕业班进行全市统一的实验操作考试。这是我市改革化学教学的重大举措之一。这次实验操作考试,要求学生在会考前对所要求初步学会、学会的实验操作进行全面复习。在此基础上确定A、B二套试题,学生各抽签做其中的一题。从试题来看还是以基本实验操作为主,如固体、液体药品的取用;滴管的使用。蒸发操作,酸碱指示剂的使用等。从我…     

河南省普通县级高中化学实验教学现状的调查研究

以河南省7个地市有代表性的县级高中为调查对象,对化学实验室基本设施情况、学生的化学学习兴趣及师生的共情能力等进行了调查,并对调查数据进行了统计分析。通过调查发现,河南省县级高中化学实验室基本设施配备良好,但缺乏实验员,通过对比发现化学实验的开设并没有明显提高学生的化学学习兴趣和化学成绩。针对调查结果,提出了将实验考试纳入高考的对策。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.