Acta Chimica Sinica
Passive film formed on 304 stainless steel in 2.5 mol/L H2SO4 solution by using alternating voltage (A. V.) passivation have been investigated by measuring capacitance and photoelectrochemical parameters. The investigation of the effect of measure frequency on the slope of Mott-Schottky curve has been carried out. The photoelectrochemical measurements were consistent with the capacitance measurement. Analysis of the experimental results showed that the passive film formed 304 stainless steel by using A. V. passivation exhibits semiconducting properties. Using the simple model of semiconductor rather than the multi-donor level model can explain satisfactorily the semiconducting behavior of the film formed on 304 stainless steel by using A.V. passivation.
关键词:
A. V. passivation;passive film;semiconducting properties;stainless;steel;model;electrodes
Fatigue & Fracture of Engineering Materials & Structures
Fatigue data for welded joints subjected to an explosion treatment (ET) were obtained using rotary bending fatigue specimens. The fatigue fracture surfaces were observed by SEM and the dislocation morphologies by TEM. Mechanical properties have been quantitively studied by considering elastic and plastic shock wave characteristics. The test results indicate that the fatigue strength of welded joints subjected to ET is apparently improved due to the action of elastic or plastic stress waves while the ductility of the welded joints, i.e., reduction in area, is greatly increased.
关键词:
唐千
,
盛明
,
王国祥
,
吴馨婷
,
袁婧雯
,
刘波
环境化学
doi:10.7524/j.issn.0254-6108.2015.03.2014070701
为了研究城市河道沉积物有机质的氧化稳定性，以氧化稳定系数（ Kos ）和腐殖化程度（ HA／FA）作为评价指标，在用H2 O2处理沉积物的基础上，探讨城市污染河道有机质含量、有机质组成等对氧化稳定性的影响．结果显示，污染河道沉积物有机质含量明显高于自然水生态系统沉积物有机质含量；富里酸（ FA）、胡敏酸（ HA）、胡敏素（ HM）是污染河道沉积物有机质主要赋存形式，其中胡敏素是主体，占全部有机质的65％以上；易氧化有机质（OMr）和难氧化有机质（OMd）与总有机质含量均显著正相关（P＜0．05）；OMd的含量可以更直观地反映河道污染程度；重污染河道沉积物有机质去除量较高；随着有机质的去除，沉积物Kos在总体上有上升的趋势；不同形态有机组分其Kos差异性明显（ P＜0．05），以HM为主的紧结态腐殖质的Kos值最高；用HA／FA和OMr可从大体上表征沉积物的氧化稳定性；HA、FA是影响城市河道沉积物氧化稳定性的主要因素．
关键词:
沉积物
,
有机质
,
氧化稳定性
,
城市污染河道
李慧玲
,
阮可青
,
王强
,
陈宇
,
钱朔
,
余勇
,
黄利
,
郑重
,
汪成友
,
曹烈兆
低温物理学报
doi:10.3969/j.issn.1000-3258.2003.04.007
研究了不同Pb含量的Bi2-xPbxSr2Co2Oy单晶的输运行为.用A. F. Ho 和A. J. Schofield提出的公式对ρc的温度依赖关系曲线进行了拟合,得到了较好的结果.我们利用小极化子理论解释了ρc的复杂行为.
关键词:
过渡金属氧化物的电导
,
小极化子
徐东
,
巫欣欣
,
程晓农
,
张剑平
,
施利毅
材料导报
采用两步烧结制备了Y_2O_3掺杂ZnO压敏瓷,其电位梯度为863～1330V/mm,非线性系数为27.0～49.7,漏电流为0.55～1.13μA.研究结果表明,当Y_2C_3的掺杂量为1.00%(摩尔分数)时,压敏瓷电性能最好,电位梯度为1330V/mm,非线性系数为49.7,漏电流为0.76μA.
关键词:
压敏瓷
,
两步烧结
,
稀土
,
显微组织
,
电性能
Hui WANG
,
Huaxia XIN
,
Jianfeng CAI
,
Fangbing LI
,
Yu JIN
,
Qing FU
色谱
doi:10.3724/SP.J.1123.2016.03006
Astragalus polysaccharides (APS) are important components in Astragalus membranaceus (A. membranaceus). However, for the huge relative molecular mass, strong polarity, and difficulty in chromatographic separation, there's a lack of quality control finely reflecting the composition of APS up to now. To solve the problems, the key lies in degradation of polysaccharides and analysis of the hydrolyzates. A partial acid hydrolysis-hydrophilic interaction liquid chromatography (HILIC) fingerprint for APS and a comprehensive quality evaluation method for A. membranaceus combining with the traditional RPLC fingerprint were developed. Orthogonal experiments were designed to investigate the influencing factors of partial hydrolysis and the conditions were optimized based on HILIC analysis. The hydrolyzates were successfully separated using HILIC-evaporative light scattering detection (ELSD) method and the optimal conditions of hydrolysis were selected as 80℃, 1.5 mol/L trifluoroacetic acid and 4 h, which proved to be stable and repeatable after the validation. This method was applied for the fingerprint analysis of 20 batches of A. membranaceus. Cosine method was used for similarity calculation using the average of samples Nos. 1-10 as reference. Moreover, RPLC fingerprint analysis was processed on other components and the data were compared for comprehensive evaluation. The similarities of ten samples with the reference ranged from 0.258 to 0.949, which were consistent with the chromatograms reflecting the apparent disparity in APS, and could be as a supplement of the RPLC fingerprint. The new method, with the advantages of intuition, convenience, and quantifiable in similarity, could reflect the differences of the composition of polysaccharides after degradation and was successfully applied in profiling of APS, contributing to the quality control together with the RPLC fingerprint.
关键词:
partial acid hydrolysis
,
hydrophilic interaction liquid chromatography (HILIC)
,
Astragalus polysaccharides (APS)
,
fingerprint
,
quality evaluation
任世科
,
骆重阳
腐蚀与防护
通过静态、动态腐蚀试验和现场应用试验,对新研制的LX3032无缝钢管在HCl-H2S-H2O环境中的腐蚀速率进行了测定.结果显示,与其他几种常用钢材相比,LX3032具有良好的耐腐蚀性能,能满足在HCL-H2S-H2O腐蚀环境下冷换设备的安全使用,腐蚀速率低于国标所限定的0.125mm/a.
关键词:
换热器
,
应力腐蚀
,
管束
李建丰
,
李勇华
,
孙硕
,
董茂军
,
欧谷平
,
张福甲
功能材料
在有机发光器件中的发光层和阴极之间插入了稳定性好、有良好电子传输能力的苝酸四甲酯(TMEP)新型缓冲层,改善了有机电致发光器件的亮度和发光效率.在电流密度为200mA/cm2时,有缓冲层的器件B效率为0.82cd/A,没有缓冲层的器件A效率为0.14cd/A.
关键词:
有机电致发光
,
TMEP缓冲层
,
发光效率
