一起戊型肝炎暴发的血清流行病学调查

目的 了解一起戊型肝炎暴发的血清学特点。方法 对某单位在10 d内先后发病的5例急性黄疸性肝炎患者、在该单位食堂就餐的1 675人(暴发人群)及未就餐的邻近单位883人(对照人群)的血清在首发病例26 d后进行抗-HEV IgM和IgG检测,数据进行统计学分析。结果5例患者抗-HEV IgM和IgG均为阳性。暴发人群抗-HEV IgM和IgG的阳性率分别为8.7％和38.4％,而对照人群仅分别为0.1％和28.6％,差别均有非常显著意义。暴发人群145例抗-HEV IgM(+)中,ALT增高32例,明显高于IgM(-)及对照;而抗-HEV IgM(-)的ALT增高比例并不高于对照人群。4例患者系列血清检测见抗-HEV IgM逐渐下降,感染后4个月多数转阴,而IgG在感染后第2-3个月达高峰,随后缓慢下降。暴发人群中抗-HEV IgM(+)的IgG平均水平最高,IgM(-)而IgG(+)的IgC平均水平亦明显高于对照,提示暴发人群中既往感染者受到了免疫加强。暴发人群中抗-HEV IgM(+)者在性别及年龄组间差异无显著意义,但其中ALT增高男性的比例显著高于女性,而与年龄无关。结论 本次急性黄疸性肝炎的暴发由戊型肝炎病毒引起,与食源有关;抗-HEV IgM和IgG不仅可用于临床病例诊断,也可用于人群调查;感染危险性与年龄及性别无关,但男性ALT增高更常见

IN SITU ECSTM INVESTIGATION ON FORMATION AND BREAKDOWN OF PASSIVE FILM FOR POLYCRYSTALLINE STAINLESS STEEL

利用电化学扫描隧道显微镜（ＥＣＳＴＭ），原位研究不同电位下不锈钢在 ０．５Ｍ Ｈ２ＳＯ４十 ０．０２Ｍ ＮａＣｌ溶液中表面形貌的动态行为，并讨论电位对不锈钢电化学阻抗谱（ＥＩＳ）的影响 结果表明：不锈钢在活化－钝化过渡区电位表面粗糙度最大；进入钝化区后，在钝化膜完整处，电位越高，表面粗糙度越小，钝化膜呈有序生长， 在钝化膜薄弱处．电位控制在０．２Ｖ时，钝化膜最为完整 在０．５Ｖ时，表面微点蚀坑开始萌生，电位为０．８Ｖ时，已有的微点蚀坑有所生长，不锈钢表面ＥＣＳＴＭ形貌与电化学阻抗谱测量呈对应关系：电位为 ０．２Ｖ时，表面钝化膜最为完整，阻抗最大；电位为 ０．５Ｖ时，在钝化膜薄弱处萌生点蚀坑，钝化膜阻抗有所下降；电位为０．８Ｖ时，钝化膜完整处得到明显的整平，阻抗相比０．５Ｖ时明显提高，但由于已萌生的微点蚀坑开始生长，阻抗相比 ０．２ Ｖ时仍有所降低。The dynamic behavior of surface topography for the stainless steel in 0.5M H2SO4+ 0.02M NaCl was traced in situ by electrochemical scanning tunneling microscope (ECSTM). The results showed a different response for the integrated passivated domain and pit-prone location on the surface when a given potentials was applied to the sample. The roughness parameter Sa for both domains appeared a maximum when controlled potential in the transition passivation region. In the potential region of passivation, passivated grains began to grow orderly on the integrated domain, and Sa decreased with increasing potential. While on the pit-prone domain, metastable micro-pits were observed when a passive potential was controlled at 0.5 V and 0.8 V. The impedance behaviors for steel sample in the different potential regions of passivation were examined by electrochemical impedance spectroscopy (EIS) and discussed based on the ECSTM results. At 0.2 V potential, the flawless surface showed the greatest impedance, and at 0.5 V, the impedance droped due to the initiation of metastable micro-pit. When controlled potential at 0.8 V, the surface roughness decreased considerably on the integrated domain, but the total impedance showed smaller resulted from the development of micro-pit in the preference location.国家自然科学基金 59525102，59871043资助项

Localized Corrosion Study of Al 2024-T3 Alloy by Scanning Micro reference Electrode Technique

应用扫描微电极技术和扫描电子显微镜技术研究Al2024-T3合金在NaCl溶液中开路状态下的局部腐蚀发生的早期过程.实验表明,当Al合金浸入NaCl溶液,其表面即刻发生局部微点腐蚀,这些微点腐蚀与合金表面第二相颗粒密切相关,Al合金表面第二相Al2CuMg颗粒可表现为三种不同的腐蚀行为.The scanning microreference electr ode(SMRE)technique and scanning electron mic roscopy(SEM)were applied to investigate the loca lized corrosion in its early stage of Al 2024-T3alloy.SMRE potential measure-ments revealed that localized corro sion occurred on the alloy surface im mediately after the exposure to 0.01mol ·L-1 NaCl solution at open-circuit poten tial,which was more negative than th e pitting potential.The potential peaks developed with time and reached the maximum after 2h exposure.Consequen tly,the heights of potential peaks would decrease and then maintained a stable value for a long time.SEM indi cated the initial of localized corro sion was associated with the second phase particles,especially the Al 2 CuMg (S phase).Three types of corrosion be-havior of S phase were observed.国家自然科学基金(59871043)资助项

In-situ ECSTM investigation on passivation surface for polycrystalline stainless steel

本文利用扫描隧道显微镜及自制的无源恒电位仪组成电化学扫描隧道显微镜 (ECSTM) ,对浸泡在 0 5mol LH2 SO4 +0 0 2mol LNaCl溶液中的Cr11Ni13 不锈钢表面进行控电位原位研究 ,获得不锈钢表面纳米尺度的动态形貌图像。实验表明 :当试样处于开路电位时 ,不锈钢表面为自然形成的均匀椭球形氧化物晶粒。当电位控制在阴极和阳极活性溶解区时 ,原来的氧化物晶粒随时间延长而缓慢消失。当电位控制在活化、钝化过渡区时 ,表面钝化膜晶粒尺寸变大 ,形状转变成半球形 ;同时有新的钝化膜晶粒生成。当控电位在钝化区时 ,钝化膜晶粒转变成月牙形 ;随电位升高 ,钝化膜发生动态重整 :晶粒呈定向有序化生长 ,表面粗糙度降低In this article, in situ topographical information of passivated surface for polycrystalline stainless steel(Cr 11 Ni 13 SS)was obtained by ECSTM. Topography of the same region was traced by STM while potentials in different regions were applied to the sample in 0 5mol/L H 2SO 4+0 02mol/L NaCl. When the applied potential changed from active dissolution region to 0V, formation of passive grains of 200nm×150nm×10nm in size was observed on the surface. While the potential rose to 0 2V, grooves between grains were leveled and grains tended to fuse together, forming a uniform shape. As the potential moving in anodical direction, the passive grains grew slowly and oriented along x y plane. Surface roughness parameter S a also became smaller with increasing potentials.国家自然科学基金资助项目 (5 95 2 5 10 2 ,5 98710 43)~

IN-SITU STM STUDY ON DYNAMIC BEHAVIOR OF CORROSION AND INHIBITION OF REBAR STEEL IN DIFFERENT SIMULATED CONCRETE PORE SOLUTION

应用STM原位观察在不同氯离子浓度和 pH值以及加入缓蚀剂前后的模拟混凝土孔溶液中的钢筋表面微观形貌 .在 pH =12 4 0的混凝土模拟孔溶液中 ,钢筋表面趋向均一 ,钝化膜的薄弱部分得到强化 ;在含 3 5 %NaCl,pH =10 4 0的混凝土模拟孔溶液中由于局部腐蚀的发生 ,可观察到不规则的沉积物的形成、生长 ;LD - 2型复合缓蚀剂能消除腐蚀活性 ,促使表面微观缺陷消亡 ,增加钝化膜的耐蚀能力 .研究结果说明 ,STM可在纳米尺度上观察表面形貌变化 ,可成为原位研究钢筋在模拟混凝土孔溶液中腐蚀和缓蚀的动态行为的重要手段 .In this paper,in situ scanning tunneling microscopy(STM)was employed to investigate morphological changes on the surface of reinforcing steel immersed in simulated concrete pore solutions(saturated calcium hydroxide).The effect of chloride,pH value and LD-2 compound inhibitor on surface morphology were studied.The sequence of images recorded in different solutions tracked the process of formation and breakdown of passive film on steel surface.The result with spatial resolution in the order of nanometer obtained from STM experiment is able to provide additional information beyond electrochemical parameters and beneficial to better understanding of the mechanism of growth and breaking down of passive film on the surface of reinforcing steel.国家自然科学基金资助项目 ( 5 98710 43,2 0 12 73 0 2 );; 福建省自然科学基金资助项目 (E0 2 10 0 0 6

Fabrication of Composite Scanning Micro pH Electrode and Its Application in Localized Corrosion

研制了一种新型的微米级复合型扫描叫探针.该探针具有体积小、响应速度快、稳定性好和制作方便等优点,能很好地满足微区 PH快速测定的要求 应用复合型扫描微pH电极技术研究了Al/Cu合金在0.01mol·L-1NaCl溶液中开路状态下局部腐蚀发生的早期过程.A novel composite scanning micro pH electrode was fabricated. The IrOx-pH electrode produced in a carbonate melt exhibited high stability, a fast potential response and ideal Nernstian response. The slope of the electrode at 15℃ was 56. 8 mV/pH, which was very close to the theoretical value. The 90% potential response time for a pH change from 1. 75 to 13. 90 was less than 0. 5 s. The composite scanning micro pH electrode is a promising apparatus for detecting the pH distribution on metal/solution interface. pH image on the surface of Al/Cu galvanic couple showed that both the anodic and cathodic areas could be sensed well. Localized corrosion took place on the interface of Al/Cu couple. The localized corrosion developed with time and pH value around the pitting decreased gradually.国家自然科学基金（59871043）资助项

Investigation on the Formation Mechanism of Ce Conversion Films on 2024 Aluminum Alloy

Ce转化膜作为一种Cr转化膜的理想替代品而日益受到人们的重视,但其成膜机理还不很清楚.本文应用自行研制的扫描微参比电极技术(SMRE),原位测量经CeCl3溶液处理的2024-T3Al合金表面微区电位分布,并结合X光电子能谱(XPS)和交流阻抗谱(EIS),对Ce转化膜的成膜机理进行探讨.结果表明,在CeCl3溶液中,Ce转化膜的形成过程是Ce3+和Cl-相互竞争的动态过程.当由Cl-的不均匀吸附引起的局部腐蚀使pH升高时,Ce(OH)3就会首先在局部位置发生沉积.阴极反应过程产生的H2O2可将Ce(OH)3部分氧化成CeO2.Many cerium compounds are promising corrosion inhibitors for aluminum alloy. However, the formation mechanism of Ce conversion films is not clear yet. Scanning microreference electrode technique (SMRE) was used to probe the potential imaging of 2024 T3 Al alloy in CeCl3 solution. The pitting corrosion of Al alloy in CeCl3 decreased with immersion time and disappeared finally. Additionally, the competition of inhibition and corrosion between Ce3+ and Cl- on Al alloy was in situ monitored in CeCl3 by SMRE. The results of X ray photoelectron spectroscopy(XPS) showed that the Ce conversion films consisted of Al2O3, CeO2 and Ce2O3(Ce(OH)3), and CeO2/Ce2O3 mass ratio decreased with immersion time. It is concluded that when thecritical pH for Ce(OH)3 formation is reached, Ce(OH)3 will precipitate at micro cathodic area of the Al alloy surface. Consequently, H2O2, the product of the catholic reaction will oxidize part of Ce(OH)3 to CeO2.国家自然科学基金(59871043)资助项目~

In situ ECSTM investigation on formation and breakdown of passive film for polycrystalline stainless steel

The dynamic behavior of surface topography for the stainless steel in 0.5M H2SO4+ 0.02M NaCl was traced in situ by electrochemical scanning tunneling microscope (ECSTM). The results showed a different response for the integrated passivated domain and pit-prone location on the surface when a given potentials was applied to the sample. The roughness parameter Sa for both domains appeared a maximum when controlled potential in the transition passivation region. In the potential region of passivation, passivated grains began to grow orderly on the integrated domain, and Sa decreased with increasing potential. While on the pit-prone domain, metastable micro-pits were observed when a passive potential was controlled at 0.5 V and 0.8 V. The impedance behaviors for steel sample in the different potential regions of passivation were examined by electrochemical impedance spectroscopy (EIS) and discussed based on the ECSTM results. At 0.2 V potential, the flawless surface showed the greatest impedance, and at 0.5 V, the impedance droped due to the initiation of metastable micro-pit. When controlled potential at 0.8 V, the surface roughness decreased considerably on the integrated domain, but the total impedance showed smaller resulted from the development of micro-pit in the preference location