检索结果-南通市图书馆

Macrocellular vitreous carbon with the improved mechanical strength

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2015年第4期9卷 413-417页

作者： oleg smorygo Alexander MARUKOVICH Vitali MIKUTSKI Andika PRAMONO Powder Metallurgy Institute National Academy of Sciences of Belarus 41 Platonov str. Minsk 220005 Belarus Research Centre for Metallurgy and Materials Indonesian Institute of Sciences (LIPI) Kawasan Puspitek 470 Serpong 15314 Banten Indonesia

Vitreous carbons with regular macrocellular structure, open intercon- nected porosity, high specific strength and hydraulic permeability were synthesized by infiltration of the epoxy resin into the sacrificial template made from the carbamide granules. Polyvinylpyrrolidone （PVP） solution in ethanol was used as the template binder. When the resin setting and the template extraction had been performed, the resultant porous material was pyrolysed in the nitrogen flow. Depending on PVP concentration in the template binder, final vitreous carbons had the following properties： bulk density at 0.17-0.22g/cm3; porosity at 85.7%-89.0%; window size at 447-735pm; Darcian permeability coefficient at （0.64-9.5）×10-9m2; non-Darcian permeability coefficient at （0.53-3.36）×10-4 m. High specific strength of above 8×10^3 Pa/（kg.m-3） was attained.

关键词： vitreous carbon cellular material porous material

维普期刊数据库

Tailoring properties of reticulated vitreous carbon foams with tunable density

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2016年第2期10卷 157-167页

作者： oleg smorygo Alexander MARUKOVICH Vitali MIKUTSKI Vassilis STATHOPOULOS Siarhei HRYHORYEU Vladislav SADYKOV Powder Metallurgy Institute National Academy of Sciences of Belarus 41 Platonov Str. Minsk 220005 Belarus Technological Educational Institute of Sterea Ellada Psahna Evias 34400 Greece Belarusian National Technical University 65 Nezavisimosty Ave. Minsk 220013 Belarus Boreskov Institute of Catalysis Sibrian Branch of Russian Academy of Sciences 5 Lavrentiev Ave. 630090 Novosibirsk Russia Novosibirsk State University 2 Pirogova Str. 630009 Novosibirsk Russia

Reticulated vitreous carbon （RVC） foams were manufactured by multiple replications of a polyurethane foam template structure using ethanolic solutions of phenolic resin. The aims were to create an algorithm of fine tuning the precursor foam density and ensure an open-cell reticulated porous structure in a wide density range. The precursor foams were pyrolyzed in inert atmospheres at 700℃, 1100℃and 2000℃, and RVC foams with fully open cells and tunable bulk densities within 0.09-0.42 g/cm3 were synthesized. The foams were characterized in terms of porous structure, carbon lattice parameters, mechanical properties, thermal conductivity, electric conductivity, and corrosive resistance. The reported manufacturing approach is suitable for designing the foam microstructure, including the strut design with a graded microstructure.

关键词： foam vitreous carbon reticulated cellular structure pyrolysis

维普期刊数据库

提高悬浮浸渍开孔泡沫Inconel 625高温合金的烧结动力学和成分均匀性

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2021年第8期31卷 2388-2401页

作者： oleg smorygo Vitali MIKUTSKI Anastasia VAZHNOVA Viachaslau HANCHAROU Serguei TIKHOV Vinod Kumar JANAGAM Amol Anant GOKHALE O.V Roman Powder Metallurgy Institute 41Platonov str.Minsk 220005Belarus Boreskov Institute of Catalysis Siberian BranchRussian Academy of Sciences5pr.LavrentievaNovosibirsk 630090Russia Defence Metallurgical Research Laboratory KanchanbaghHyderabad 500058India Indian Institute of Technology Bombay PowaiMumbai 400076India

采用悬浮液浸渍法制备开孔泡沫Inconel 625高温合金,先用混合粉末悬浮液复制纯镍泡沫带,然后进行热处理。本研究的目的是寻找一种合适的方法,在不使用低熔点添加剂的情况下,确保泡沫高温合金带的完全致密化,并在适中的烧结温度下获得均... 详细信息

采用悬浮液浸渍法制备开孔泡沫Inconel 625高温合金,先用混合粉末悬浮液复制纯镍泡沫带,然后进行热处理。本研究的目的是寻找一种合适的方法,在不使用低熔点添加剂的情况下,确保泡沫高温合金带的完全致密化,并在适中的烧结温度下获得均匀的化学成分。通过扫描电子显微镜和能谱仪对上述方法制备的泡沫带的显微组织和成分变化进行表征,并对其准静态压缩性能进行评估。结果表明,用Cr、Mo和Ni元素粉末作为高温合金粉末悬浮液的添加剂,在适中的烧结温度下,可获得化学成分均匀、密度高、符合Inconel 625标准的高温合金粉末悬浮液。这是因为低熔点共晶的形成,以及存在元素粉末时大的成分梯度所产生的非平衡热力学条件加速了扩散动力学。

关键词：高温泡沫合金悬浮液复制烧结扩散显微组织

维普期刊数据库

The Silk roads: phylogeography of Central Asian dice snakes (Serpentes: Natricidae) shaped by rivers in deserts and mountain valleys

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2024年第2期70卷 150-162页

作者： Daniel Jablonski Konrad Mebert Rafaqat Masroor Evgeniy Simonov oleg Kukushkin Timur Abduraupov Sylvia Hofmann Department of Zoology Comenius University in BratislavaBratislavaSlovakia Global Biology BirrSwitzerland Pakistan Museum of Natural History ShakarparianIslamabadPakistan Severtsov Institute of Ecology and Evolution Russian Academy of SciencesMoscowRussia T.I.Vyazemski Karadag Scientific Station-Nature Reserve—Branch of A.0.Kovalevsky Institute of Biology of the Southern Seas TheodosiaCrimea Zoological Institute of the RAS Saint PetersbourgRussia Institute of Zoology Academy of Sciences of the Republic of UzbekistanYunusabadTashkentUzbekistan Museum Koenig Bonn LIBLeibniz Institute for the Analysis of Biodiversity ChangeBonnGermany UFZ-Helmholtz Centre for Environmental Research Department of Conservation BiologyPermoserstrasse 1504318 LeipzigGermany

Influenced by rapid changes in climate and landscape features since the Miocene,widely distributed species provide suitable models to study the environmental impact on their evolution and current genetic *** dice snake Natrix tessellata,widely distributed in the Western Palearctic is one such *** aimed to resolve a detailed phylogeography of *** with a focus on the Central Asian clade with 4 and the Anatolia clade with 3 mitochondrial lineages,trace their origin,and correlate the environmental changes that affected their distribution through *** expected time of divergence of both clades began at 3.7 Mya in the Pliocene,reaching lineage differentiation approximately 1 million years *** genetic diversity in both clades is rich,suggesting different ancestral areas,glacial refugia,demographic changes,and colonization *** Caspian lineage is the most widespread lineage in Central Asia,distributed around the Caspian Sea and reaching the foothills of the Hindu Kush Mountains in Afghanistan,and Eastern European lowlands in the *** distribution is limited by deserts,moun-tains,and cold steppe ***,Kazakhstan and Uzbekistan lineages followed the Amu Darya and the Syr Darya water systems in Central Asia,with ranges delimited by the large Kyzylkum and Karakum *** the western side,there are several lineages within the Anatolia clade that converged in the central part of the peninsula with 2 being endemic to Western *** distribution of both main clades was affected by expansion from their Pleistocene glacial refugia around the Caspian Sea and in the valleys of Central Asia as well as by environmental changes,mostly through aridification.

关键词： biogeography colonization Eurasia genetic diversity mitochondrial DNA Paratethys refugia water snakes.

Enhanced electric-field induced strain in Eu3+ doped 0.67BiFeO3-0.33BaTiO3 lead-free piezoelectric ceramics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第9期42卷 1747-1754页

作者： Wei Li Tongxiang Liang Xiang He Vyunov oleg Dongfang Pang Shan Wu College of Rare Earths Jiangxi University of Science and Technology Key Laboratory of High Performance Ceramics and Ultrastructure Shanghai Institute of CeramicsChinese Academy of Sciences

Lead-free ferroelectric ceramics,0.67Bi1-xEuxFeO3-0.33BaTiO3（BF-BT-xEu,x=0-0.02）,were prepared via a solid-state reaction,The effect of Eu3+doping on the microstructure,dielectric properties,ferroelectric properties,and electric-field-induced strain was *** X-ray diffraction（XRD） results indicate the presence of a mixed phase of tetragonal and rhombohedral at the morphotropic phase boundary（MPB）.Doping with an appropriate amount of Eu3+reduces the Fe3+content and decreases the leakage current in the binary system.A converse piezoelectric coefficient(d33*) of 392 pm/V is obtained at BF-BT-0.003Eu under an electric field of 60 kV/cm at room temperature,which has a Curie temperature（TC） of 414℃,The unipolar strain and d33* of BF-BT-0.003Eu ceramics increase to 0.438%and 730 pm/V at 125℃ The field-induced strain response of the BF-BT-0.003Eu ceramics is greater than that of 0.67BF-0.33BT,mainly due to its optimal grain size,reduction of leakage current,and coexistence of ferroelectric-relaxation phases,BF-BT-0.003Eu ceramic is a lead-free candidate for high-temperature actuator applications.

关键词： Ferroelectric Field-induced strain Ceramics Lead-free Rare earths

伯醇对镍基催化剂在转移氢化反应中的抑制作用研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2024年第3期58卷 168-179页

作者： Nikolay Nesterov Alexey Philippov Vera Pakharukova Evgeny Gerasimov Stanislav Yakushkin oleg Martyanov 博列斯科夫催化研究所俄罗斯新西伯利亚

本文研究了在转移加氢条件下,不同类型醇作为氢供体对镍基催化剂在苯并呋喃加氢反应中的活性影响.结果表明,使用异丙醇作为氢供体时,苯并呋喃的加氢过程为底物先发生脱芳构化,然后再进行脱氧反应.然而,当使用伯醇如甲醇、乙醇和正丙醇... 详细信息

本文研究了在转移加氢条件下,不同类型醇作为氢供体对镍基催化剂在苯并呋喃加氢反应中的活性影响.结果表明,使用异丙醇作为氢供体时,苯并呋喃的加氢过程为底物先发生脱芳构化,然后再进行脱氧反应.然而,当使用伯醇如甲醇、乙醇和正丙醇作为氢供体时,会导致镍基催化剂的不可逆失活.针对这一现象,进一步研究了伯醇使镍基金属催化剂失活的机理.结果表明,在250°C条件下,催化剂与伯醇的相互作用会导致形成非活性的碳化物Ni_(3)C,并且镍金属颗粒在氧化铝载体表面会发生烧结和偏析.

关键词：苯并呋喃转移加氢超临界共沉淀 Ni催化剂醇

从BRDF到BPDF:遥感反演基础模型的演进初探

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国科学:信息科学 2024年第8期54卷 2001-2020页

作者：尚可晏磊张飞舟褚君浩杨彬刘思远 Kevin TANSEY 贾秀萍 oleg DUBOVIK 张子晗李飞北京大学地球与空间科学学院遥感与地理信息系统研究所北京大学空间信息集成与3S工程应用北京市重点实验室中国科学院上海技术物理研究所红外物理国家重点实验室湖南大学电气与信息工程学院中国兵器工业导航与控制技术研究所 School of Geography Geology and the Environment University of Leicester School of Engineering and Technology The University of New South Wales Laboratoire d'Optique Atmosphérique CNRS/Université Lille

光的本质是横波电磁波矢量,以双向反射分布函数BRDF (bidirectional reflectance distribution function)为基础模型的标量遥感体系只利用植被反射光的整体强度信息,无法进一步区分反射辐射蕴含的叶表、叶内和冠层结构信息;在标量遥感... 详细信息

光的本质是横波电磁波矢量,以双向反射分布函数BRDF (bidirectional reflectance distribution function)为基础模型的标量遥感体系只利用植被反射光的整体强度信息,无法进一步区分反射辐射蕴含的叶表、叶内和冠层结构信息;在标量遥感基础上考虑垂直于电磁波传播方向的二维偏振矢量特性(强度+方向)就能深化为矢量遥感体系,从而有望精确刻画反射光中蕴含的多种信息,提升植被参数反演精度.刻画偏振反射空间分布的双向偏振分布函数BPDF目前存在精度低、泛化性差等问题,因此进一步探索矢量遥感基础理论,构建通用性强的植被矢量遥感基础模型具有迫切的现实需求.本文旨在利用光子与植被元素的相互作用构建通用性较强的植被BPDF物理模型.首先基于光子–植被元素相互作用的光谱不变原理,提出基于方向逃逸概率的植被BPDF物理模型基础形式,并基于植被单次反射的辐射传输理论推导模型解析表达;随后通过考虑叶片散射随干物质含量的变化,提出光谱不变原理优化表达并推导模型通用表达式;最后分别利用三维矢量辐射传输模型和多尺度实测数据实现模型的正演直接验证和间接验证.结果表明,本文构建的BPDF物理模型的解析表达和通用表达在不同植被场景下,对偏振反射率的正演均方根误差可达0.001以内,与矢量辐射传输模型正演结果在半球空间内具有很强一致性,在多尺度实测数据也简洁验证了模型关系的稳定性,模型R2普遍高于0.9.相比于现存植被偏振反射模型,本文构建的模型兼具物理机理、简洁形式、可接受的参数化方案、较高精度和较强泛化能力,对浓密植被具备通用性,为在BRDF一维标量遥感的基础上进一步考虑BPDF二维偏振特性从而形成矢量遥感体系这一转变过程提供了理论基础和探索性方案.

关键词：植被 BPDF 矢量遥感物理模型偏振

同方期刊数据库

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry traces the geographical source of Biomphalaria pfeifferi and Bulinus forskali,involved in schistosomiasis transmission

在线全文

学校读者我要写书评

暂无评论

Infectious Diseases of Poverty 2024年第1期13卷 98-99页

作者： Papa Mouhamadou Gaye EI Hadj Ibrahima Ndiaye Souleymane Doucoure Doudou Sow Mapenda Gaye Ndiaw Goumballa Carole Cassagne Coralie L'Ollivier oleg Medianikov Cheikh Sokhna Stephane Ranque Aix-Marseille University IRD AP-HM SSA VITROME Marseille France VITROME International IRD-UCAD Campus Dakar Senegal Hospital-University Institut (IHU) Mediterranée Infection Marseille France Departement of Animal Biology Faculty of Sciences and Techniques UCAD Dakar Senegal Department of Parasitology-Mycology UFR Sciences de la Santé Université Gaston Berger Saint-Louis Senegal

Background Freshwater snails of the genera Bulinus spp.,Biomphalaria spp.,and Oncomelania *** the main intermediate hosts of human and animal *** of these snails has long been based on mor-phological and/or genomic criteria,which have their *** limitations include a lack of precision for the morphological tool and cost and time for the DNA-based ***,Matrix-Assisted Laser Desorp-tion/lonization Time-Of-Flight(MALDI-TOF)mass spectrometry,a new tool used which is routinely in clinical microbi-ology,has emerged in the field of malacology for the identification of freshwater *** study aimed to evaluate the ability of MALDI-TOF MS to identify Biomphalaria pfeifferi and Bulinus forskali snail populations according to their *** This study was conducted on 101 *** and 81 *** snails collected in three distinct geo-graphical areas of Senegal(the North-East,South-East and central part of the country),and supplemented with wild and laboratory *** which had previously been morphologically described were identified by MALDl-TOF MS[identification log score values(LSV)≥1.7],after an initial blind test using the pre-existing *** DNA-based identification,new reference spectra of ***(n=10)and ***(n=5)from the geographical areas were added to the MALDI-TOF spectral *** final blind test against this updated database was per-formed to assess identification at the geographic source *** MALDI-TOF MS correctly identified 92.1%of 101 *** snails and 98.8%of 81 *** *** the final blind test,88%of 166 specimens were correctly identified according to both their species and sampling site,with LSVs ranging from 1.74 to *** geographical source was adequately identified in 90.1%of 91 *** and 85.3%of 75 *** *** Our findings demonstrate that MALDI-TOF MS can identify and differe

关键词： Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry Snail Intermediate host Biomphalaria pfeifferi Bulinus forskali Schistosomiasis Senegal

Presepsin as a biomarker of bacterial translocation and an indicator for the prescription of probiotics in cirrhosis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2024年第5期16卷 822-831页

作者： Irina Efremova Roman Maslennikov Elena Poluektova oleg Medvedev Anna Kudryavtseva George Krasnov Maria Fedorova Filipp Romanikhin Maria Zharkova Oxana Zolnikova Gyunay Bagieva Vladimir Ivashkin Department of Internal Medicine Gastroenterology and HepatologySechenov UniversityMoscow 119435Russia Department of Scientific Scientific Community for the Promotion of the Clinical Study of the Human MicrobiomeMoscow 119435Russia Department of Pharmacology Lomonosov Moscow State UniversityMoscow 119192Russia Department of Post-Genomic Research Laboratory Engelhardt Institute of Molecular BiologyRussian Academy of SciencesMoscow 119991Russia

BACKGROUND The gut–liver axis and bacterial translocation are important in cirrhosis,but there is no available universal biomarker of cellular bacterial translocation,for which presepsin may be a *** To evaluate the relationship of the blood presepsin levels with the state of the gut microbiota in cirrhosis in the absence of obvious *** This study included 48 patients with Child–Pugh cirrhosis classes B and C and 15 healthy *** fecal microbiome was assessed using 16S rRNA gene *** levels of presepsin were measured.A total of 22 patients received a probiotic(Saccharomyces boulardii)for 3 *** Presepsin levels were higher in patients with cirrhosis than in healthy individuals[342(91-2875)vs 120(102-141)pg/mL;P=0.048].Patients with elevated presepsin levels accounted for 56.3%of all included *** had lower levels of serum albumin and higher levels of serum total bilirubin and overall severity of cirrhosis as assessed using the Child–Pugh *** with elevated presepsin levels had an increased abundance of the main taxa responsible for bacterial translocation,namely Bacilli and Proteobacteria(including the main class Gammaproteobacteria and the minor taxa Xanthobacteraceae and Stenotrophomonas),and a low abundance of bacteria from the family Lachnospiraceae(including the minor genus Fusicatenibacter),which produce short-chain fatty acids that have a positive effect on intestinal barrier *** presepsin level directly correlated with the relative abundance of Bacilli,Proteobacteria,and inversely correlated with the abundance of Lachnospiraceae and *** 3 months of taking the probiotic,the severity of cirrhosis on the Child–Pugh scale decreased significantly only in the group with elevated presepsin levels[from 9(8-11)to 7(6-9);P=0.004],while there were no significant changes in the group with normal presepsin levels[from 8(7-8)to 7(6-8);P=0.123].A high level of presepsin

关键词： Dysbiosis Gut Intestinal permeability Leaky gut Gut-liver axis Liver Microbiota