如何教给同学系统的，巩固的化学基础知识

在中学化学教学大纲上指示,中学化学教学的基本任务:“第一就是使学生获得一定的系统的和巩固的化学基本知识……。”我觉得这样的要求是非常恰当的。系统的鞏固的化学基本知识,就不是零碎的、片面的、散乱的一堆化学材料,而是系统的、科学的、自然界物质变化的规律;不是无用的、累赘的、死板的知识,而是学了化学之後,能获得合乎高等学校要求的化学基础,或是直接为国家的生产建设服务。因而在正确的进行系统的、鞏固的基本化学知识的讲授     

纳米材料的自组装研究进展

本文主要评述了近年来纳米材料自组装的研究进展，即对以纳米材料(包括零维的纳米粒子和一维的纳米管/线)为单元而开展的自组装方面的工作进行了介绍。将纳米材料自组装为各种尺度的有序结构会产生更优异的整体的协同性质，这对于以纳米材料为基础而构筑的微纳米器件有着重要的意义。由于目前纳米材料的研究主要集中在零维和一维体系，因此，本文分别就此两种体系的自组装行为进行了评述。具体内容包括：单分子层薄膜修饰的无机纳米粒子的自组装、大分子修饰的无机纳米粒子的自组装、未被修饰的无机纳米粒子的自组装；表面张力及毛细管力诱导的一维纳米材料的自组装、模板诱导的一维纳米材料的自组装、静电力诱导的一维纳米材料的自组装。     

结构化学展望

结构化学是探讨化学物质的微观结构以及它和宏观性能之间相互关系的基础科学,是化学学科的一个重要分支。这里所谓微观结构,指的是原子-分子层次的结构,包括分子中原子的空间排列以及原子基团之间的相对空间排布;分子的各种内部运动,包括分子的转动,原子间的振动和其中电子的运动;这些不连续的(即量子化的)运动状态给出的能级的分布。经典的化学结构理论曾经正确地指出:物质的内部结构完全决定了它的典型化学反应性能(实际上也同时决定了大部分其它方面的性能);反过来,通过这些典型化学反应性能的研究,原则上也应该能定出化     

化学的进步——庆祝中国化学会成立六十周年

中国化学会正式成立已经60年了。这是人类社会进步速度最快的60年,无论从科学的进步或是学会工作的发展,老一辈的化学家或年轻一代的化学家、教授、研究员或工程师,搞研究的、教学的或是搞工业的,各种角度,各种眼光,无不感到我们所处的时代是快速前进的,充满激情的,无数机会的。老一代的忆往昔,峥嵘岁月;年轻的看前景,光辉未来。中国化学会在这样的时刻庆祝它的六十周年,特别具有深远意义。     

元素的化学性质与原子结构

在高三的化学教材中讲到元素的化学性质与原子结构的关系时,只谈到得失电子的难易是决定于该元素的原子最外层电子的数目,我认为这样是不够完善的。如能使学生对元素的原子(或离子)半径有所认识,了解原子(或离子)半径的大小和核电荷以及电子层数的关系,了解电子得失的难易还取决于原子(或离子)半径的大小,这就有助于他们深入的掌握化学知识。增加这部分内容是不会增加学生的负担的,我们只引导他们考虑,如几种元素的原子具有相同数目的电子层,核电荷较大的,则由于静电引力的缘故,它对核外电子的引力必较大,最外电子层的电子当然也被吸引,因此,原子     

聚合物不同相态X-射线衍射的数学描述

<正> 由于电子计算机的迅速发展和广泛应用,使得已被国内外普遍用来研究聚合物结构的“分峰法”(分解聚合物的X-射线衍射重叠峰的方法)成为一个切实可行的、有效的新方法。分峰法的前提和基础是要有反映聚合物各相态X-射线衍射峰峰形规律的合理的和确切的数学模型,这对聚合物结构的研究有着直接的重要的影响。七十年代迄今,国内外现有的关于聚合物不同相态的X-射线衍射的数学描述尚无通用的、统一的形式,     

化学成绩提高的方法

为社会主义建设的成就和伟大的共产主义思想所鼓舞的千千万万的教师大军,坚持不懈地获得巩固的、深刻的和自觉的知识,培养学生们的苏维埃爱国主义和苏维埃民族自豪感,无限忠诚於伟大的苏联共产党。出现了很多没有留级生的教师。作为一个比较年轻的化学教师的我,愿意提供一下我自己如何消灭留级生现象的意见,并且肯定地说,克服留级生现象的任务是完全可以解决的。     

中国共产党中央委员会的唁电

苏联共产党中央委员会: 中国共产党全体同志和中国人民以无可比拟的悲痛的心情,哀悼我们最敬爱的导师和我们最真挚的朋友斯大林同志的逝世。斯大林同志的逝世是我们共同事业的不可估量的损失。斯大林同志是世界工人阶级的伟大领袖,人类解放的伟大旗帜。他和伟大的列宁在     

对本刊“关于相规的推导方法的建议”一文的意见

1956年化学通报6月号刊载了彭周人先生所写的“关于相规的推导方法的建议”一文,其中在叙述R′的关系的举例时,略有疏忽的地方,似应加以明确如下: R是系统的各纯物质间必须满足的独立的化学平衡关系的数目,R′是系统的某些纯物质的浓度变数在某些情况下必须满足的独立的限制条件的数目。在考虑有化学平衡存在时,R就是独立的化学平衡关系的数目,而R′的存在却要看系统的具体情况方能确定。彭先生在举例中说“例如2H_20=H_3O~++OH~-离解平衡中,     

铌钽化学ⅪⅩˉ⑴——铌钽的分离方法及其基础

具有工业意义的金属铌及金属?的分析及制备的分离法是困难的,文内系统的整理了主要的分离法或聚集法,阐明了它们的基础,那些利用低的氧化级或中间的水解级不同安定性的操作法显得特殊重要和适宜。     

The depth distribution of organic additives in mortar measured with plasma-based Secondary Neutral Mass Spectrometry

Amino alcohols (AMA) have been found to be successful in corrosion prevention of steel-reinforced concrete [1]. However, to work effectively the amino alcohol has to be located at the interface between the concrete and the steel rods reinforcing the stability of the building material [2]. Corrosion prevention for new buildings is easy because the corrosion inhibitor has already been added to the liquid concrete mixture and thus can easily reach the steel rods. With subsequent corrosion prevention measures for existing buildings, however, the problem of transport of the corrosion inhibitor through the solid concrete to the steel surface has to be solved first. In order to determine penetration, transport behavior, and transport rate, an AMA was applied to one face of rectangular mortar blocks used as model samples. A certain period of time for dwelling was given to allow the AMA to penetrate into the mortar. Moreover, the influence of the ambient humidity during the application was investigated. The analysis of the mortar was made by Secondary Neutral Mass Spectrometry, a technique used for the first time for this type of material because of the easy sample preparation, short analysis time, and high sensitivity.     

模拟混凝土孔隙液中D-葡萄糖酸钠复合缓蚀剂对钢筋的阻锈作用

应用电化学技术, 结合扫描电子显微镜(SEM)观测, 研究D-葡萄糖酸钠、钼酸钠和硫脲三组分复合缓蚀剂对模拟混凝土孔隙液中钢筋腐蚀行为的影响及其阻锈作用. 结果表明: 在含3.5% (w) NaCl的模拟混凝土孔隙液中, 复合缓蚀剂具有协同效应, 对钢筋有良好的阻锈作用. 当D-葡萄糖酸钠、钼酸钠和硫脲浓度分别为750、250和500 mg·L^-1时, 对钢筋的缓蚀效率可达到94.5%. 应用软硬酸碱(HSAB)理论分析缓蚀机理, 可认为三组分复合缓蚀剂在钢筋表面共同形成保护膜而阻止钢筋的腐蚀.     

Electrochemical and Surface Analysis Studies on the Carbon Dioxide Corrosion of X‐65 Carbon Steel

A comprehensive study of the CO₂ corrosion of carbon steel (X‐65) at low partial pressures of CO₂ is reported in this paper. Field emission scanning electron microscopy (FESEM), Raman spectroscopy (RS), synchrotron radiation‐grazing incidence X‐ray diffraction (SR‐GIXRD), and electrode kinetic studies have confirmed that chukanovite, magnetite and siderite are the main corrosion products at low partial pressures of CO₂. Chukanovite forms predominantly in the presence of CO₂, while magnetite was found to be the major corrosion product in the absence of CO₂, although the majority of previous work based on conventional ex‐situ materials characterization techniques has implied that siderite is the main corrosion product. Here, it is shown that the nature of corrosion products is strongly dependent on the experimental conditions at low pressures of CO₂, which has not been elucidated in previous studies. Accordingly, this study has made a significant contribution to identifying the true nature of corrosion scales formed at low partial pressures of CO₂ allowing the development of effective anti‐corrosive agents for the control and prevention of carbon steel corrosion at low CO₂ partial pressures.     

Scientific fraud in corrosion science research: A review

This article examines the issue of scientific misconduct and its implications on corrosion science research through a decade (2001–2011). An analysis is presented of an increasing body of cases in which allegations have been made and violations of legal and ethical research standards have been substantiated. The frequencies with which scientists fabricate and falsify data, or commit other forms of scientific misconduct, are discussed. In this review, the image of scientists as objective seekers of truth is periodically jeopardized by the discovery of a major scientific fraud. This review shows how easy it can be for a scientist to publish fabricated data in the most prestigious journals, and how this can cause a waste of financial and human resources. Case examples illustrated and investigated in this review are related to corrosion science research. Recommendations toward the prevention and resolution of potential or actual instances of scientific misconduct in corrosion science research are proposed.     

Sol–Gel-Derived Corrosion-Protection Coatings

There is a current need for alternative coatings that can provide corrosion resistance to metals or alloy surfaces due to the environmental hazards posed by conventional coatings. Herein, we report on novel organically-modified sol–gel coatings for the protection of metal and alloy surfaces. The basic concept of chemical conversion of metal surfaces is based on deposition of a hydrophobic, nonporous sol–gel barrier layer for surface protection and corrosion prevention. The properties of these organosilica coatings can be tuned by varying the composition of precursors. The evaluation of hydrophobicity, adhesive strength, and anticorrosion properties of organically-modified sol–gel derived coatings suggests their potential utility as technologically-compatible alternatives to conventional coatings.     

Corrosion protection of carbon steel in acidic media by expired bupropion drug; experimental and theoretical study

The effects of expired bupropion on the corrosion protection of carbon steel in hydrochloric acid (1.0 M) and sulfuric acid (0.5 M) solutions were examined by Fourier transform infrared (FTIR) spectroscopy, Tafel polarization and electrochemical impedance spectroscopy (EIS). Bupropion concentrations in both acid solutions were raised, which improved corrosion prevention. Bupropion was a mixed inhibitor because it retarded the anodic and cathodic processes, as indicated by polarization data. The inhibition efficiency decreased with the increasing temperature from 25 to 55 °C. In the presence of bupropion, the activation energies of corrosion in both acid solutions increased. The thermodynamic quantities were deduced from the influence of temperature on the corrosion process of carbon steel in both acid media. Bupropion adsorption on carbon steel followed the Langmuir adsorption isotherm. The polarization data yielded outcomes consistent with the results arising from impedance measurements. FTIR spectroscopy showed the active sites of bupropion molecule during adsorption on the alloy surface. The theoretical study and molecular dynamics simulation of bupropion was done by a density functional theory (DFT) approach to realize the effects of molecular structure on the inhibitive action of bupropion.     

Methylchlorophosphanes and Their Reaction Products

Methyldichlorophosphane and dimethylchlorophosphane can be prepared only with considerable difficulty. The ease with which they yield numerous reaction products is an indication of the pronounced reactivity of these organohalophosphanes. Possible applications of such organophosphorus compounds exist inter alia in the fields of plant protection, corrosion prevention, and flame retardants, as well as in the catalysis of gas phase reactions, for instance the desulfurization of gas mixtures.     

Band edge modulated conjugated polymers for oxidation prevention

The impact of electron transfer (ET) from a series of band edge modulated polymers to atmospheric oxygen is examined in connection with substrate oxidation prevention. Polymers with the highest occupied molecular orbital (HOMO) energy level below and above the oxygen energy level were tested and the former showed better efficiency. Furthermore, the oxidation prevention efficiency of a polymer with lower HOMO increased by two orders of magnitude, when the pores on the film were filled with spherical molecules, [6,6]-phenyl-C61-butyric acid methyl ester. We found that the polymer surface hydrophobicity has little or no influence on oxidation prevention. It is interesting to note that a polymer with a hole mobility of 8 × 10(-10) cm(2) V(-1) s(-1) showed a two-fold increase in oxidation prevention efficiency compared to a polymer with a hole mobility of 6 × 10(-5) cm(2) V(-1) s(-1). Over all, from the concerted approach, we conclude that a polymer devoid of pores with the HOMO energy level below oxygen and low charge carrier mobility is a suitable candidate for prevention of substrate oxidation/corrosion.     

Experimental and theoretical studies of carbon steel corrosion protection in phosphoric acid solution by expired lansoprazole and rabeprazole drugs

The effects of expired lansoprazole and rabeprazole on the corrosion protection of carbon steel in phosphoric acid (3.0 ?M) solution were examined by Tafel polarization and electrochemical impedance spectroscopy (EIS). Lansoprazole and rabeprazole concentrations (0.5, 1.0, 5.0 and 10 ?mM) in acid solution were raised, which improved corrosion prevention. Both lansoprazole and rabeprazole as the mixed inhibitors retarded the anodic and cathodic processes, as indicated by polarization data. With the increasing temperature in the range of 25–55 ?°C, the inhibition efficiency drops from 92.9% to 69.3% for lansoprazole and from 94.8% to 74.2% for rabeprazole. The major decrease in the inhibition efficiency with ascending temperature proved the physisorption of the drugs. The activation energies for carbon steel corrosion in H₃PO₄solution were enhanced from 41.6 ?kJ ?mol^?1 to 81.9 ?kJ.mol^?1and 85.9 ?kJ ?mol^?1 for lansoprazole and rabeprazole, respectively. The influence of temperature on the corrosion process of carbon steel in the acid medium was used to derive the thermodynamic quantities of corrosion. The adsorption of both lansoprazole and rabeprazole on carbon steel followed the Langmuir adsorption isotherm. The polarization data yielded outcomes that were consistent with the results arising from impedance measurements. The theoretical study of both lansoprazole and rabeprazole was done by a density functional theory (DFT) approach to realize the effects of molecular structure on their inhibitive action. Both lansoprazole and rabeprazole contain a higher E_HOMO, a lower E_LUMO and a lower energy gap than some inhibitors earlier reported as good corrosion inhibitors in the literature.