电极制作方法对电解二氧化锰循环伏安行为的影响

采用压制泡沫镍、石墨棒模具、粉末微电极三种电极制作方法研究电解二氧化锰在硫酸镁溶液中的循环伏安行为,并用X射线衍射法分析电解二氧化锰放电/充电后结构形态的变化。结果表明:用粉末微电极制作的研究电极在循环伏安扫描过程中反应灵敏、解析度好,所得循环伏安谱图中还原、氧化峰的变化与X射线衍射谱图中衍射峰的变化具有较好的对应关系,能更真实地反映电解二氧化锰的电化学性质。     

5-硝基-1,4-萘醌在玻碳电极上的电化学行为研究

采用循环伏安法和线性扫描伏安法,研究了5-硝基-1,4-萘醌在玻碳电极上的电化学行为.结果表明,在丙酮的稀硫酸溶液中,5-硝基-1,4-萘醌在0.0V、-0.8V(vs.SCE)处各有一个还原峰,分别为硝基、醌的不可逆电极反应;5-硝基-1,4-萘醌在电极表面的传质为线性扩散,电还原过程由扩散控制,并求得传递系数分别为...     

方波伏安法测定孔雀石绿上染率

采用循环伏安法和方波伏安法研究了阳离子染料孔雀石绿(MG)在H2SO4底液(pH 1.0)中的电化学行为.在0.1 V/s的扫描速率下,MG在碳糊电极上显示一个不可逆氧化峰:0.82 V(Pa,2);一对准可逆氧化还原峰:0.51 V(Pa,1)、0.48 V(Pc)(Ep vs.SCE).在0.05～0.9 V/s的扫速范围内,3个峰的峰电流与扫速的平方根都成正比,表明MG的电氧化还原过程均受扩散控制.计时库仑法测得MG的扩散系数为2.31×10-7cm2/s,表面覆盖度是1.18×10-11mol/cm2.还原峰Pc的峰电流与MG的浓度在8.00×10-6～1.00×10-4 mol/L范围内呈线性关系,检出限为6.6 μmol/L(S/N=3),染色工艺中常用的匀染剂"平平加O"和MG染色体系中常见的无机离子不干扰测定.本方法用于测定MG上染腈纶的上染率,结果与分光光度法一致.     

舒乐安定吸附伏安法的研究

Jimenez曾研究了舒乐安定的性质,但灵敏度较低,本文提出了测定痕量舒乐安定的吸附伏安法,在0.1 mol/L NH_3-NH_4Cl溶液(pH 9.3)中,富集电位—0.80 V(us. Ag/AgCl)得一灵敏的舒乐安定还原峰,Ep=—1.05 V,i_p与舒乐安定浓度在3.0×10~(-9)～5.0×10~(-6) mol/L范围内呈线性关系,检测限达1.0×10~(-9)mol/L,并用于试样的测定,用循环伏安法和恒电     

钇离子在氟化物体系中的电化学还原

用循环伏安法和卷积伏安法研究钇离子在LiF-NaF-YF_3熔融盐中的阴极还原过程。结果表明,在实验条件下钇离子的电化学反应为一步还原,阴极过程受扩散控制,产物钇与铂形成合金。     

循环伏安法研究超分子有机凝胶中二茂铁的扩散

4,4′-二(硬脂酰胺基)-二苯甲烷(BSAPM)在LiClO4/碳酸丙烯酯(PC)中能形成超分子有机凝胶。用循环伏安法研究了包埋在凝胶中的二茂铁的氧化还原行为。结果表明,有机凝胶内的二茂铁仍具有氧化还原活性,其氧化还原行为是受扩散控制的单电子可逆转移过程。与溶液相比,最低化凝胶浓度下凝胶中二茂铁和二茂铁离子的扩散系数分别从5.62×10-6cm2/s和6.47×10-6cm2/s下降为3.32×10-6cm2/s和4.41×10-6cm2/s,且随凝胶因子浓度的增加,凝胶中二茂铁和二茂铁离子的扩散系数降低。     

双嘧达莫在玻碳电极上的阳极伏安法研究

用直流伏安法(DCV),微分脉冲伏安法(DPV)和循环伏安法(CV)在玻碳电极(GCE)上研究了双嘧达莫(DPM)在不同介质中的阳极伏安行为,发现在0.01mol/LCHl溶液中于0.62V(vs.Ag/AgCl)右左生产一个阳极氧化峰,其峰高与浓度的线性方程分别为r=0.0004 0.17C(0.05~1.0mg/L)和y=0.052 0.22C(0.5~10mg/L). 在此体中大多数金属离子和20多种有机生代物质不干扰测定,采用该方法可不经分离,直接测定药物制剂和尿样吕DPM的含量,同时对DPM的电极反反应机理进行了探讨.     

Dawson型磷钨杂多阴离子P2W18O6-62的电化学性质和对O2还原的电催化作用

用循环伏安、交流伏安和交流阻抗法对Dawson型磷钨杂多阴离子P2W18O66-2的电化学性质进行了详细研究,循环伏安结果显示,P2W18O66-2在pH2.52的0.1mo·lL-1Na2SO4+NaHSO4溶液中有两对可逆的单电子还原-氧化波和两对可逆的双电子还原-氧化波.单电子波的峰电位和电流与溶液的pH无关,双电子波的峰电位则随溶液pH的增加而负移,峰电流降低,表明双电子电极过程完全受扩散控制,实验测定其扩散系数(DO)为2.5×10-6cm2-1.循环伏安结果表明P2W18O6-62的第III对波对O2还原为H2O2具有显著的电催化作用,催化效率约达300%.将P2W18O6-62应用于PW11O39Fe(III)(H2O)4-构成的类电-芬顿过程,使该过程对硝基苯的降解效率显著提高.     

循环伏安法定性分析矿物中某元素硫氧化物占比

根据硫化矿和氧化矿在电解液为硫酸钠的三电极体系中循环伏安曲线的差异，建立了循环伏安法定性分析矿物中某元素硫氧化物占比的方法，以铜的硫化物(黄铜矿)和氧化物(孔雀石)纯矿物进行循环伏安法测试。结果表明，在扫描速率0.1 V/s,扫描电压范围-0.8 V～0.8 V时，黄铜矿循环伏安曲线出现氧化还原峰，孔雀石循环伏安曲线未见明显氧化还原峰；黄铜矿和孔雀石混合物循环伏安曲线上的氧化还原峰电位与单一黄铜矿的氧化还原峰电位几乎一致，但峰电位对应的电流大小与矿物占比存在一定的关系。由此，可以通过循环伏安法定性判断混合矿中黄铜矿与孔雀石的占比，实现循环伏安法定性分析矿物中某元素硫氧化物占比。     

6-糠氨基嘌呤的电化学行为及与DNA的相互作用

应用循环伏安法、微分脉冲伏安法和紫外光谱法研究了6-糠氨基嘌呤(6-KT)在汞电极上的电化学行为及与小牛胸腺DNA的相互作用.结果发现,6-KT的循环伏安曲线显示两对表征为扩散控制和吸附控制的氧化还原波.扩散控制波的氧化峰电流随6-KT浓度在1.00×10-4～5.00×10-2mmol·L-1范围内呈现良好的线性关系.依据预吸附时间和溶液pH值对吸附控制波的还原峰电位和峰电流的影响,讨论了6-KT在汞电极上的吸附机理.另外,6-KT的扩散控制波的还原峰电流随DNA浓度的增加而减小,峰电位正移,紫外吸收峰出现明显的减色效应,认为6-KT乃通过部分插入作用与DNA结合,结合常数为2.60×103 L·mol-1.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。