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A new strategy for corrosion protection of porous stainless steel using polypyrrole films

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Journal of Materials Science & Technology 2020年第2期37卷 85-95页

作者： C.Garcia-Cabezon C.Garcia-Hernandez M.L.Rodriguez-Mendez f.martin-Pedrosa Materials Engineering E.I.I.Universidad de Valladolid47011 ValladolidSpain UVASENS E.I.I.Universidad de Valladolid47011 ValladolidSpain

In this work,a method to improve the protection against corrosion of porous sintered stainless steel is *** is based on the electrodeposition of polypyrrole(PPy)layers doped with a large size counterion such as dodecylbenzenesulphonic acid(DBSA),a conducting polymer with high corrosion resistance and good *** efficacy of PPy coating depends on the adequate adhesion between the metal substrate and the coating *** protection against corrosion has been tested using 316 L stainless steel(SS)powder sintered at different conditions to evaluate the effect of the sintering atmosphere(nitrogen and vacuum)and cooling rates(furnace and water)on corrosion resistance,while wrought 316 L SS has been used as reference *** addition,two electrochemical deposition techniques have been tested to select the most *** circuit potential evolution,anodic polarization measurements and electrochemical impedance spectra have been used to evaluate corrosion protection in phosphate buffer saline *** has been evidenced that a more homogeneous and stable coating was obtained in the case of porous stainless *** corrosion potential shifted to nobler values and the anodic polarization branch became more *** porous samples have a good passivation performance with a lower stable passive current density and a higher breakdown *** transfer electronic resistance and the impedance module increase more than one order of ***,the porosity of sintered stainless steel is seen as an advantage for the improvement of the adherence of the PPy *** best corrosion protection is found for samples sintered in nitrogen and water-cooled.

关键词： Stainless steel Powder metallurgy Protection corrosion Electrodeposited films Polymer coatings

Archaea, the tree of life, and cellular evolution in eukaryotes

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Science China Earth Sciences 2019年第3期62卷 489-506页

作者： Jing XIAO Lu fAN Dingfeng WU Yanbing XU Dengxun LAI William f.martin Ruixin ZHU Chuanlun ZHANG Department of Bioinformatics Tongji University Shenzhen Key Laboratory of Marine Archaea Geo-Omics Department of Ocean Science and Engineering Southern University of Science and Technology SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology Institute of Molecular Evolution Heinrich-Heine-University Universit?tsstr.1 Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology

The early history of life harbours many unresolved evolutionary questions, none more important than the genomic origin and cellular evolution of eukaryotes. An issue central to eukaryote origin concerns the position of eukaryotes in the tree of life and the relationship of the host lineage that acquired the mitochondrion some two billion years ago to lineages of modern-day archaea. Recent analyses indicate that the host lineage branches within the Archaea, prompting the search for novel archaeal lineages that can improve our understanding of the cellular evolution of eukaryotes. Here we give a brief review of the studies on Archaea, the tree of life and the cellular evolution of eukaryotes, which is followed by an overview of recent progress fueled by new genomic technologies and recent status of archaeal research in China. future directions for the study of early evolution are considered.

关键词： Archaea Tree of life Cellular evolution of eukaryotes Metagenomics Bioinformatics

OBSERVING THE HEAT EQUATION ON A TORUS ALONG A DENSE GEODESIC

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Systems Science and Mathematical Sciences 1991年第2期4卷 186-192页

作者： Lance D.Drager Robert L.foote Clyde f.martin Department of Mathematics Texas Tech.University.LubbockTX 79409USA Department of Mathematics Wabash CollegeCrawfordsvilleIN 47933USA Department of Mathematics Texas Tech.UniversityLubbockTX 79409USA

Several authors have considered observability problems for the heat equation and relatedpartial differential equations.A basic problem is to determine what kinds of sampling providesufficient information to uniquely determine the initial heat *** address the case wherethe temperature is measured while travelling along a *** consider the special case where the space is a flat torus(of arbitrary dimension)and thecurve is a *** is shown that,in this case,the observed temperature is sufficient informationto uniquely determine the initial heat distribution if and only if the geodesic is dense in the *** the case of a torus,fourier analysis techniques can be used to write down the solution of theheat *** allows us to derive an explicit representation of the observed temperature interms of the initial *** use this representation and some ideas from the theory ofalmost periodic functions to show that the fourier coefficients of the initial distribution can berecovered from the observation.

关键词： Observability heat equation inverse problems

Improvements in tribological and anticorrosion performance of porous Ti–6Al–4V via PEO coating

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friction 2021年第5期9卷 1303-1318页

作者： C.Garcia-Cabezón M.L.Rodríguez-Méndez V.AmigóBorrás R.Bayón C.Salvo-Comino C.Garcia-Hernandez f.martin-Pedrosa Materials Engineering E.I.I.Universidad de ValladolidValladolid 47011Spain BioecoUVA Research Institute Universidad de ValladolidValladolid 47011Spain Group UVASENS Escuela de Ingenierías IndustrialesUniversidad de ValladolidValladolid 47011Spain Instituto de Tecnología de Materials Univesitat Politécnica de ValenciaValencia 46022Spain Tribology Unit Fundación IK4-TeknikerEibar 20600Spain

Medical implants manufactured using biomaterial Ti–6Al–4V exhibit some *** higher elastic modulus than that of natural bone can cause stress shielding *** can be avoided using Ti–6Al–4V with pores in the implant ***,poor corrosion and tribocorrosion behaviors are yielded because of the large area exposed to the *** mitigate both issues,coating technologies can be *** plasma electrolytic oxidation(PEO)process is a cost‐effective process that has been used successfully in nonporous Ti *** this study,two PEO coatings with different amounts of Ca/P are ***,reports regarding their application in porous materials are *** effects of PEO treatments on corrosion and tribocorrosion in Ti–6Al–4V powder metallurgy are analyzed *** porous materials provide an efficient surface for PEO coatings,as demonstrated via scanning electron microscopy(SEM)and atomic force microscopy(AfM),and the porosity of the substrates improved the adherence of the *** corrosion resistance measured via electrochemical impedance spectroscopy confirmed the beneficial effect of the coatings,particularly for long exposure *** lower roughness,small pore size,and more compact film observed in the PEO–Ca/P sample resulted in favorable tribological and corrosion properties.

关键词： Ti‐based alloys corrosion tribocorrosion surface modification

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青霉素和头孢菌素生物合成中的基因克隆

药学进展 1989年第4期13卷 36-39页

作者： Juan f.martin 肖灿鹏

二十世纪,生物技术为抗生素的工业发酵生产提供了基础。然而,尽管发酵产量有了很大提高,但抗生素生物合成机制了解还不够。研究分离的抗生素合成过程中编码酶的基因,是加深了解的重要步骤。工业上发酵生产抗生素已建有一个完整体系,但... 详细信息

二十世纪,生物技术为抗生素的工业发酵生产提供了基础。然而,尽管发酵产量有了很大提高,但抗生素生物合成机制了解还不够。研究分离的抗生素合成过程中编码酶的基因,是加深了解的重要步骤。工业上发酵生产抗生素已建有一个完整体系,但对产生菌的生物合成和控制这些微生物代谢产物产生的分子机理的基础研究还很欠缺。因为抗生素生物合成的研究进展很缓慢,其部分原因是参与生物合成酶类的本身不稳定之故,所以,对β-内酰胺类(青霉素、头孢菌素、cephamycin、carbapenems、monobactams)来说,虽与青霉素、头孢菌素及cephamycins的生物合成有关的一些

关键词：产黄青霉转化子青霉素抗菌素基因克隆生物合成生化反应野生型菌株结构基因头抱菌素质粒载体

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青霉素和头孢菌素生物合成的基因克隆化

国外医药（抗生素分册） 1989年第1期10卷 11-13,7页

作者： Juan f.martin 李文伦

工业发酵生产抗生素已完全建立,但对微生物代谢物的生产控制的分子机制和生物合成尚缺乏基础研究。了解抗生素生物合成的进展部分由于所涉及的酶的固有不稳定性而一直很缓慢。因此对β-内酰胺类抗生素(青霉素类、头孢菌素类、头霉素类... 详细信息

工业发酵生产抗生素已完全建立,但对微生物代谢物的生产控制的分子机制和生物合成尚缺乏基础研究。了解抗生素生物合成的进展部分由于所涉及的酶的固有不稳定性而一直很缓慢。因此对β-内酰胺类抗生素(青霉素类、头孢菌素类、头霉素类、碳青霉烯类、单酰胺菌素类而言,已鉴定了涉及青霉素、头孢菌素和头霉素生物合成的某些酶,但尚未综述生物合成途径及其控制机理。抗生素产生菌的分子遗传学还处于发展的早期阶段。产黄青霉和顶头孢霉中重组DNA技术的应用将导致合理构建含多拷贝抗生素生物合成基因的菌株。

关键词：青霉素头孢菌素生物合成基因克隆化

Comparison of intravitreal ranibizumab and bevacizumab for the treatment of macular edema secondary to retinal vein occlusion

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International Journal of Ophthalmology(English edition) 2014年第1期7卷 86-91页

作者： Alex Yuan Baseer U.Ahmad David Xu Rishi P.Singh Peter K.Kaiser Daniel f.martin Jonathan E.Sears Andrew P.Schachat Justis P.Ehlers Vitreoretinal Service Cole Eye InstituteCleveland Clinic The Retina Institute

AIMTo compare the efficacy of ranibizumab and bevacizumab for macular edema due to retinal vein occlusion (RVO).

关键词： macular edema retinal vein occlusion bevacizumab ranibizumab optical coherence tomography

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“大气河”风暴来袭

环球科学 2022年第19期 48-55页

作者： f.马丁·拉尔夫雍阳阳(翻译) 美国加利福尼亚大学圣戈分校斯克利普斯海洋研究所西部天气与极端水灾中心不详

某个星期一的早上,我在美国旧金山市中心的西尔斯美食(Sears fine food)餐厅一边吃早餐,一边漫不经心地看着柜台后面的电视屏幕,上面正在播放当地未来5天的天气预报。屏幕底部的一个小符号显示着一个带着笑脸的太阳,这表明当天余下的时... 详细信息

某个星期一的早上,我在美国旧金山市中心的西尔斯美食(Sears fine food)餐厅一边吃早餐,一边漫不经心地看着柜台后面的电视屏幕,上面正在播放当地未来5天的天气预报。屏幕底部的一个小符号显示着一个带着笑脸的太阳,这表明当天余下的时间里将是阳光灿烂。到了星期三,天气符号就变成了一朵友好的云彩与几点雨滴,星期四则是乌云密布并伴有更多的雨滴。

关键词：电视屏幕西尔斯乌云密布天气符号天气预报雨滴

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古菌、生命树和真核细胞的功能演化

中国科学：地球科学 2019年第7期49卷 1082-1102页

作者：肖静范陆吴顶峰徐雁冰赖登训 William f.martin 朱瑞新张传伦同济大学生物信息系上海200092 南方科技大学深圳海洋地球古菌组学重点实验室深圳518055 南方科技大学前沿与交叉科学研究院深圳518055 Institute for Molecular Evolution University of Düsseldorf 青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室青岛266061

当前对早期生命演化过程的研究仍存在许多尚未解决的问题,其中以真核生物"基因组起源"和"细胞功能演化"最为重要,回答该问题的关键在于确定真核生物在生命树中的位置以及20亿年前获得线粒体的宿主与现代古菌之间的关系.最新研究认为真... 详细信息

当前对早期生命演化过程的研究仍存在许多尚未解决的问题,其中以真核生物"基因组起源"和"细胞功能演化"最为重要,回答该问题的关键在于确定真核生物在生命树中的位置以及20亿年前获得线粒体的宿主与现代古菌之间的关系.最新研究认为真核生物是从属于古菌的一支,而新古菌的不断发现将进一步推动"真核细胞功能演化"的研究.文章先对有关"古菌"、"生命树"和"真核细胞功能演化"的研究进展及挑战进行梳理,之后单独总结了当前中国的古菌研究现状,最后从"宏基因组"、"生物信息学方法"和"古菌的分离培养"三方面对通过构建古菌系统发育推动生命演化研究提出展望.

关键词：古菌生命树真核细胞功能演化宏基因组学生物信息学