硫脲对块体纳米晶工业纯铁在盐酸溶液中的缓蚀行为

采用电化学阻抗谱(EIS)研究了硫脲对室温下1 mol•L－1盐酸溶液中粗晶和纳米晶工业纯铁的腐蚀行为的影响.从EIS的拟合结果得知,在1 mol•L－1盐酸溶液中,块体纳米晶工业纯铁比粗晶工业纯铁腐蚀倾向小.基于纳米晶和粗晶工业纯铁在添加有硫脲的1 mol•L－1盐酸溶液中阻抗谱随浸泡时间的变化关系,观察到以下现象,当浸泡时间短至5 min时,对应不同浓度(50、100、150、500 mg•L－1)的缓蚀剂添加量,在粗晶工业纯铁的阻抗复平面图上出现一感抗弧,而在纳米晶工业纯铁的阻抗复平面图是一圆心下偏的容抗弧.随着浸泡时间的延长,两种样品的容抗弧半径增大,在150 mg•L－1的浓度时,电荷传递电阻(Rct)出现极值,这表明硫脲是一种吸附型缓蚀剂.抗盐酸腐蚀性能的提高和没有感抗弧的出现, 归因于体纳米化的结果,这与体纳米化的制备技术密切相关.     

工业用水中铁含量的双光束FIA光度法

工业用水中铁含量的双光束ＦＩＡ光度法赵珍义（辽宁大学化学系沈阳１１００３６）李淑凡（辽宁武警总队医院）流动注射分析（ＦＩＡ）具有取样量少、分析速度快、精密度好等优点而被广泛用于分析测试之中［１，２］。目前，ＦＩＡ光度法均采用单光束而开展的研究工作。尚...     

Pulse polarographic determination of trace amounts of cobalt (II) by complex formation with calcon

Some aspects of the polarographic reduction of sodium 1-(2-hydroxy-1-naphthylazo)-2-naphthol-4-sulphonate (trivial name: calcon or Eriochrome Blue Black R), as observed when using differential pulse polarography (d.p.p.) and alternating current polarography (a.c.p.), are described, as well as the polarographic behaviour of this compound in the presence of some metal ions. The peak that appears in the d.p.-polarogram due to the reduction of the cobalt (II) complex is the basis of a method for the determination of very small trace amounts of cobalt(II). The proposed procedure is rather selective (Ni(II) interferes, Mn(II) does not) and has a limit of detection of 7 g 1^–1 (minimum amount which can be determined 0.6 g Co(II)).     

Indirect determination of free cyanide in water and industrial waste water by flow injection-atomic absorption spectrometry

A simple and rapid flow injection system is proposed for indirect determination of cyanide by flame atomic absorption spectrometry. It consists of a microcolumn of immobilized salen (N,N′-bis(salicylidene)ethylenediamine) on sodium dodecyl sulfate (SDS)-coated alumina saturated with silver ion and a carrier of dilute solution of sodium hydroxide (10⁻⁵ mol L⁻¹). The micro-column was located between the injection valve and nebulizer of atomic absorption spectrometry. Injection of 250 μL of aqueous cyanide standard or sample solution at pH range of 9–11 cause elution of silver as silver cyanide complexes, which was then measured by flame atomic absorption spectrometry. The absorbance was proportional to the concentration of cyanide in the sample. The graph of absorbance (as peak height) vs. cyanide concentration was linear over the concentration range of 0.1–10 mg L⁻¹ of cyanide, and the detection limit was 0.06 mg L⁻¹. The relative standard deviation at 1 and 3 mg L⁻¹ of cyanide concentration were 4.1 and 4.7%, respectively. The method was successfully applied to determination of cyanide in water and industrial waste waters, and the accuracy was examined through independent analysis by accepted method of pyridine-barbituric acid.     

Inclusion Compounds — possibility of their combination and use in different branches of chemistry

Hofmann-type and related compounds, a natural zeolitic material of the clinoptilolite type, and cyclodextrins have been studied. Different products, useful in the separation of organic mixtures, used with fertilizers and insecticides in agrochemistry, perfumes, and in the detoxication of raw materials, have been prepared by combinations of the inclusion compounds studied. In the Hofmann-type compounds and cyclodextrins the original guest is substituted; in the zeolite the original sorbate, as well as some part of the zeolitic host is substituted. The physical mixtures of the starting materials differed from the products in their thermal, spectral and diffractographic characteristics. Field test results and other supporting evidence are added.     

气提吸附／热脱附／气相色谱－质谱法分析污水中的痕量有机物

采用气提吸附／热脱附／气相色谱－质谱法对齐鲁公司所处地区工业污水进行分析。方法采用Ｔｅｎａｘ－ＧＣ吸附剂对样品进行气提吸附，脱附时样品直接进入色谱仪汽化室，一次进样即可完成全组分分析，共检测出含四氯丙醚在内的４０种有机组分，测定了各组分的程序升温保留指数。气相色谱－质谱法测定出四氯丙醚三个异构体的结构。     

Electrochemical Impedance Spectroscopic Investigation in Detecting 2,4‐dinitrophenylhydrazine Using Catalytic Effect of Copper at Glassy Electrode

This paper reports on the use of electrochemical impedance spectroscopy (EIS) allied to copper (II) for the determination of 2,4‐dinitrophenylhydrazine (DNPH) at glassy carbon electrode (GCE). The experiment measurements were carried out in methanol at a potential of 0.3 V versus Ag/AgCl. The Nyquist plots were modeled with a Randle equivalent circuit, by identifying the charge transfer resistance as the relevant concentration dependent parameter. These measurements show that the impedance spectra of DNPH increased by the formation of non‐electroactive compound produced from specific interaction between DNPH and Cu (II), which will block the electron‐transfer process of the redox probe. Therefore, the proposed methodology offers a detection limit of 4.0×10^?8 mol L^?1. The proposed methodology was satisfactorily applied to determine DNPH in industrial water samples.     

福建省能源效率影响因素灰色关联分析

利用2005-2014年样本数据,应用灰色关联分析法分析人均地区生产总值、工业增加值占地区生产总值比重、第三产业增加值占地区生产总值比重、工业能源消耗量、煤炭消耗量占一次能源消耗比重、燃料动力类价格指数及研发占地区生产总值比重对福建省能源效率的影响程度.从分析结果看,工业能源消耗量、工业增加值占地区生产总值比重及研发占地区生产总值比重对福建省能源效率的影响较大,而能源价格对福建省能源效率的拉动作用最小.这说明现阶段加强高耗能行业的结构调整、加大清洁能源技术的研发投入、完善能源价格机制,并充分发挥政府干预在节能减排中的作用是福建省提高能源效率的重要途径,也是贯彻落实节能减排政策的关键.     

基于灰色关联模型的新能源汽车产业竞争力评价研究

新能源汽车产业已经成为汽车产业未来发展方向;而提高产业竞争力,能够有效降低新能源汽车产业运营费用,增进企业效益.在相关文献研究的基础上,构建了6个一级指标和28个二级指标的新能源汽车产业竞争力评价体系;借鉴灰色关联评价模型对广东省、福建省和湖北省新能源汽车产业竞争力的相关数据展开了实证研究.研究结果表明,与福建省与湖北省的情况相比,广东省新能源汽车产业的支持力度出现了较大变化,政策的推动对产业竞争力的提升和市场的扩大起到了极大的促进作用.     

基于解释结构模型的大学生就业能力因子分析——以工业工程专业为例

运用调查法从用人单位和应届大学毕业生两个视角提取20个就业能力因子,发现不同视角下,就业能力因子存在较大差异.构建大学生就业能力因子解释结构模型,结果显示,20个因子可分为4层,一些处于模型底层的因子没有得到大学生足够的重视,这也是导致应急式的大学生就业能力培养模式和用人单位招聘困境的根本原因.注重"循序渐进"的提高、强化"专业技术"和"个性心理"两个方面核心能力的培养、用人单位介入培养过程是提升大学生就业能力的有效途径.