竹叶提取物对LST12钢在NH_4Cl溶液中的缓蚀作用

用失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了竹叶提取物(DLMLE)在0.5mol/L NH_4Cl溶液中对冷轧钢的缓蚀作用。结果表明:DLMLE在NH_4Cl溶液中对冷轧钢具有良好的缓蚀作用,缓蚀率随缓蚀剂质量浓度的增加而增大,最大缓蚀率可达85.9%;DLMLE在冷轧钢表面的吸附符合Langmuir吸附等温式,吸附过程为物理吸附和化学吸附的混合吸附过程;DLMLE为混合抑制型缓蚀剂,EIS谱呈单一压扁的半圆容抗弧,电荷转移电阻随缓蚀剂质量浓度的增加而增大。     

2,4-二氨基嘧啶对冷轧钢在HCl溶液中的缓蚀作用

通过浸泡试验、电化学试验和扫描电子显微镜(SEM)观察研究了2,4-二氨基嘧啶(DAP)在1.0mol/L HCl溶液中对冷轧钢的缓蚀作用。结果表明:DAP在HCl溶液中对冷轧钢具有良好的缓蚀作用;缓蚀率随缓蚀剂含量的增大而增大,DAP浓度为10.0mmol/L时缓蚀率最大,可达94.8%;DAP为混合型抑制型缓蚀剂,DAP在冷轧钢表面的吸附符合Langmuir吸附等温式,缓蚀率随温度的升高而下降。     

滇润楠叶提取物在H_3PO_4中对钢的缓蚀性能研究

采用失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了滇润楠(Machilus yunnanensis)叶提取物(MYLE)在1.0 mol/L H3PO4中对冷轧钢缓蚀作用。结果表明:MYLE在1.0mol/L H3PO4溶液中对冷轧钢具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,但随温度的升高而降低。MYLE在钢表面的吸附符合Temkin吸附等温式。MYLE为混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区出现小段感抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大。     

硫酸中核桃叶提取物对钢的缓蚀性能

核桃叶提取物是一种"绿色"缓蚀剂.本文采用失重法、动电位极化曲线研究了核桃叶提取物在0.5mol/LH2SO4溶液中对冷轧钢的缓蚀作用.结果表明:核桃叶提取物对冷轧钢具有较好的缓蚀作用,在冷轧钢表面的吸附符合校正的Langmuir吸附等温式,极化曲线表明,核桃叶提取物为混合型缓蚀剂.     

2-巯基嘧啶对冷轧钢在乙酸溶液中的缓蚀作用

采用失重法、电化学法、扫描电子显微镜(SEM)和红外光谱(FTIR)研究了2-巯基嘧啶(MP)对冷轧钢在乙酸(CH_3COOH)溶液中的缓蚀作用。结果表明:MP对冷轧钢在2. 5 mol/L乙酸溶液中具有良好的缓蚀效果,在MP浓度为2. 0 mmol/L,温度为20~40℃条件下,失重法测得最大缓蚀率均超过92%; MP在冷轧钢表面的吸附规律符合Temkin吸附等温式,该吸附过程放热且伴随熵增加,为包含物理吸附与化学吸附的混合吸附过程; MP为通过"几何覆盖效应"起作用的混合抑制型缓蚀剂; Nyquist图呈单一时间常数的弥散容抗弧,添加MP后电荷转移电阻显著增大,但双电层电容值明显下降; MP在冷轧钢表面形成吸附膜层,该吸附膜层主要含有MP及Fe(CH_3COO)_2、FeOOH和Fe_2O_3。     

核桃叶提取物在盐酸介质中对钢的缓蚀性能

核桃（Juglans）叶提取物（JLE）可以作为“绿色”环保的植物缓蚀剂。本工作采用失重法和动电位极化曲线研究了JLE在1mol／LHCI溶液中对冷轧钢的缓蚀作用。结果表明,JLE对冷轧钢具有较好的缓蚀作用,且存钢表面的吸附符合校正的Langmuir吸附等温式,极化曲线表明,JLE为混合抑制型缓蚀剂。     

空心莲子草提取物对冷轧钢在HCl溶液中的缓蚀性能

以乙醇水溶液为提取剂从空心莲子草中得到提取物(APE),并用红外光谱(FTIR)和紫外光谱(UV)表征了APE的官能团和UV吸收曲线。利用失重法、电化学法、扫描电子显微镜(SEM)观察、接触角测试等研究了APE在0.50mol/L HCl溶液中对冷轧钢的缓蚀性能。结果表明:APE对冷轧钢在HCl溶液有显著的缓蚀效果,50℃100mg/L APE的缓蚀率高达97.1%;缓蚀率随缓蚀剂量的增大先增大后趋于平稳,随温度升高稍有增加。APE为混合抑制型缓蚀剂,其在冷轧钢表面的作用机理为"几何覆盖效应";添加APE后电荷转移电阻显著增加,但界面双电层电容值下降。APE在钢表面的吸附符合表观Langmuir吸附等温式,吸附方式既存在化学吸附又有物理吸附;SEM观察和接触角测试结果表明,APE显著减缓了冷轧钢表面的腐蚀,且增强了其表面的疏水性。     

元宝枫叶提取物在硫酸中对钢的缓蚀作用

采用失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了元宝枫叶提取物在0.5 mol/L H28O4溶液中对冷轧钢腐蚀的影响.结果表明:元宝枫叶提取物对冷轧钢具有良好的缓蚀作用,且在钢表面的吸附符合Langmuir吸附等温式;元宝枫提取物为混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区出现感抗弧,电荷转移电阻随...     

高氯油田水溶液中咪唑类缓蚀剂的性能

采用失重试验和电化学方法研究了苯并咪唑及6-硝基苯并咪唑两种缓蚀剂在含氯油田水溶液中对Q235钢的缓蚀作用,并探讨其缓蚀机理,研究了两种缓蚀剂添加量对缓蚀效率的影响。结果表明,苯并咪唑及6-硝基苯并咪唑缓蚀剂都具对Q235钢有明显的缓蚀作用,苯并咪唑缓蚀率随着浓度增大呈现增大趋势,浓度为1.0g/L时缓蚀效果最好,缓蚀率达90.41%;6-硝基苯并咪唑的缓蚀率随着浓度的增大具有极值效应,当浓度为0.5g/L时,最大缓蚀率为84.78%。极化曲线和电化学阻抗谱试验结果与失重法的结果一致,都表明在油田水溶液中苯并咪唑的缓蚀率较6-硝基苯并咪唑高。苯并咪唑的缓蚀效果较6-硝基苯并咪唑更好,且两种缓蚀剂在Q235钢表面的吸附都为自发过程,符合Langmuir吸附等温式。     

木薯淀粉接枝共聚物在盐酸介质中对冷轧钢的缓蚀作用

采用氧化还原引发体系引发木薯淀粉与丙烯酰胺接枝共聚反应制备的天然木薯淀粉接枝共聚物(SGA),可以作为一种环境友好型绿色缓蚀剂。本文用失重法、动电位极化曲线、电化学阻抗(EIS)和扫描电子显微镜(SEM)首次研究了SGA在1.0mol/L HCl溶液中对冷轧钢的缓蚀作用。结果表明,SGA对冷轧钢具有良好的缓蚀作用,在钢表面的吸附符合Langmuir吸附等温式,为混合抑制型缓蚀剂;EIS谱呈半圆容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大。SEM表明SGA在钢表面吸附形成了致密的缓蚀剂膜层。     

加速发展我国的快速成形技术

介绍了第二届北京国际快速成形及制造会议概况，分析了快速成形（RP）技术的发展趋势，指出RP技术研究领域的重大进展及学科发展的主攻方向是：由RP向快速制造（RM）发展，由RP向快速模具（RT）发展，RP技术在生物医学领域的应用。     

Electrochemical behaviour of amorphous and nanoquasicrystalline Zr-Pd and Zr-Pt alloys in different environments

The corrosion behaviour of melt spun amorphous and nanoquasicrystalline Zr₇₀Pd₃₀ and Zr₈₀Pt₂₀ alloy ribbons has been investigated using potentiodynamic polarization study in NaCl, H₂SO₄ and NaOH solutions at different concentrations. The amorphous and nanoquasicrystalline alloys show better corrosion resistance than Zr in all the solutions studied. Both the alloys are susceptible to chloride attack and pitting has been observed. Complete passivation has been observed in H₂SO₄, while gradual break down of passivating layer occurs in NaOH. In general, nanoquasicrystalline state in both the alloys shows better corrosion resistance than amorphous state in all the solutions studied.     

Effect of solution heat treatment on galvanic coupling between intermetallics and matrix in AA7075-T6

Susceptibility to localised corrosion is strongly affected by heat treatments performed on Al-Zn-Cu-Mg alloys. In order to study how galvanic coupling between intermetallics and matrix is affected by solution heat treatment, AA7075-T6 and solution heat treated AA7075 have been characterised by means of scanning electron microscopy and scanning Kelvin probe force microscopy. Solution heat treatment strongly increased the Volta potential difference between the intermetallics and the surrounding matrix showing a strong increase in galvanic coupling. This is explained by Zn and Mg enrichment of the matrix caused by dissolution of strengthening particles during solution heat treatment.     

Effect of moisture (in solid polymer electrolyte) on the photosensitivity of conducting polypyrrole sensitized by prussian blue in solid-state photocells

The effect of small concentration of dispersed prussian blue (PB) [in solid polymer electrolyte viz polyvinyl alcohol (PVA) with phosphoric acid] on the photocurrents were studied (in wet state and in dry state of solid polymer electrolyte) in solid state photocells fabricated using conducting polypyrrole (PPy). These exhibit good photoresponse to visible light: photocurrents being 20 to 25 times greater than the dark currents depending upon the concentration of the sensitizer. The current–voltage (I–V) characteristics in such cells reveals that the charge transport is mainly governed by the space charge effects and the sensitization effects are due to the lowering of the potential barrier formed at the polypyrrole (PPy)/polyvinyl alcohol (PVA) interface under photoexcitation. Also, sensitization effects were studied in the wet state and in dry state of solid polymer electrolyte (PVA). It has been observed that the moisture content in the solid polymer electrolyte reduces the photosensitivity factor (S=I_l/I_d, where I_l is the light current and I_d is the dark current), since it increases the ionic conductivity in the solid polymer electrolyte thereby increasing the dark current values which results in overall decrease in the photosensitivity factor (S). The importance of the other factors such as dye concentration, dye aggregation etc. have been explained on the basis of the experimental observations. The sensitization effects are explained on the basis of the energy band diagram of the materials forming the photocells.     

CIMS在特钢厂的应用

论文介绍了CIMS系统提出的背景、基本概念和作用,并结合某特钢厂项目中的实际应用,对CIMS系统在项目实施中的系统功能、体系结构与功能模块组成进行了说明,给出了具体实例.     

Corrosion resistance of HVOF sprayed HastelloyC nickel base alloy in seawater

The nickel base alloy, HastelloyC, deposited by HVOF thermal spraying, was investigated to ascertain the characteristics as a protective coating for the structural steels under the marine environment. Its corrosion resistance was evaluated in addition to its physical and its chemical properties. The HastelloyC deposit with higher impermeability had a comparatively higher corrosion resistance in artificial seawater. It possessed a nature of general corrosion because of its contamination by oxidation of flying particles during the spray process. In the case of the porous deposit, a reaction similar to the crevice corrosion took place on pores between its sprayed particles.     

头孢哌酮/舒巴坦体外抗菌活性的研究

目的 研究头咆哌酮单用,及与舒巴坦联用在体外的抗菌活性。方法 采用琼脂平板稀释法测定头孢哌酮/舒巴坦(SPZ,比例1:1)、头孢哌酮(CPZ)和舒巴坦(SBT)对8种322株临床常见致病菌的最低抑菌浓度(MIC),并统计MIC₅₀、MIC₉₀ 、IC₅₀等数值。结果 除金黄色葡萄球菌外,SPZ对其它7种致病菌的抗菌活性均强于CPZ,MIC₉₀值均下降2~4倍;SPZ对肺炎链球菌、流感嗜血杆菌的MIC₅₀值较CPZ有极大的降低;SPZ对53.2%的肠菌科细菌和40.7%的绿脓假单胞菌的MIC值有2倍以上的降低,9.04%的肠杆菌科细菌和33.3%的绿脓假单胞菌对CPZ耐药,52.9 %和50.0 %的CPZ耐药菌对SPZ敏感。SBT虽对受试菌均无明显抗菌活性,但其可能通过对β-内酰胺酶的抑制作用,提高了CPZ的抗菌活性。结论 SPZ可适用于CPZ耐药菌引起的严重感染。     

Influence of metal ions on the formation of artificial zinc rusts

The artificial rust particles were prepared from ZnCl₂ solutions dissolving Al(III), Fe(III), Fe(II), Ni(II), Co(II) and Mg(II) at different atomic ratios from 0 to 0.3 in metal/Zn. With increasing metal/Zn the crystal phases of the products turned following as ZnO → a mixture of ZnO and Zn₅(OH)₈Cl₂ · H₂O (ZHC) → ZHC. Al(III) most facilitated the formation of ZHC but Mg(II) and Fe(III) produced no ZHC. The morphology of the formed particles varied following as agglomerate → fine → rod → sheet → irregular with the increase of metal/Zn. The sheet and irregularly shaped particles were identified as ZHC and the other particles as ZnO.     

Corrosion in artificial defects. II. Chromate reactions

Artificial defects, in the form of slots, were milled through a chromate-containing protective paint system on AA2024-T3 and exposed to neutral salt spray (NSS). Proton induced X-ray emission (PIXE), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS), electron microprobe analysis (EMPA), and Raman spectroscopy were used to characterise the primer and the alloy surface. Chromate was released by the primer to form a 40 μm depletion zone around the edge of the slot. Within the depletion zone, the chromate was reduced but not completely removed. Chromate was detected in the runoff from the slots and was also found to have reacted with the exposed alloy surface. Chromate was found to react with intermetallic particles, smears formed by the milling process, and pits.