检索结果-南通市图书馆

Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第5期13卷 383-388页

作者： Soliman, H.M. Ohamed, k.e. Abd el-Azim, M.e. Hammad, F.H. Metallurgy Dept. Atomic Energy Authority Cairo Egypt

Low and medium carbon steels were aluminized by the pack aluminizing technique using halideactivated pure-Al and fe-Al packs. The effect of mixture composition, aluminizing temperatureand time and C content of the steel substrate on the structure and thickness of the aluminidelayer, and on the oxidation resistance was investigated. The optimum oxidation resistance canbe achieved with a low carbon steel substrate when the intermetallic phases fe3Al and feAlform the surface of the aluminide layer. In this case, the Al concentration at the surface of thealuminide coating is at least ≥15 wt pct. Formation of high Al concentration phases (feAl3 andfe2Al5) during aluminizing should be avoided as they tend to embrittle the aluminide layer andreduce its oxidation resistance.

关键词： OO Figure Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

Finite element modeling assumptions impact on seismic response demands of MRF-buildings

在线全文

学校读者我要写书评

暂无评论

earthquake engineering and engineering Vibration 2018年第4期17卷 821-834页

作者： Shehata e Abdel Raheem Ahmed k Abdel Zaher Ahmed MA Taha Civil engineering Department Engineering College Taibah University Civil engineering Department Faculty of Engineering Assiut University

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（fe） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable fe models with various levels of refinement. The effects of the fe modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a fe model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

关键词： RC-MRF buildings design codes provisions seismic design finite element modeling modeling assumptions response demands

STUDY ON THe CATALYTIC ReACTION OF ACeTONe TO DIACeTONe ALCOHOL

在线全文

学校读者我要写书评

暂无评论

催化学报 1996年第5期17卷 466-471页

作者： Sun Hongwei He fe DepartmentofChemicalengineering TianjinUviversity DepartmentofChemicalengineeri

ＳＴＵＤＹＯＮＴＨＥＣＡＴＡＬＹＴＩＣＲＥＡＣＴＩＯＮＯＦＡＣＥＴＯＮＥＴＯＤＩＡＣＥＴＯＮＥＡＬＣＯＨＯＬＳｕｎＨｏｎｇｗｅｉ，ＨｅＦｅｉ，ＸｕＧｅｎｈｕｉ＊，ＭａＸｉｎｂｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃ... 详细信息

ＳＴＵＤＹＯＮＴＨＥＣＡＴＡＬＹＴＩＣＲＥＡＣＴＩＯＮＯＦＡＣＥＴＯＮＥＴＯＤＩＡＣＥＴＯＮＥＡＬＣＯＨＯＬＳｕｎＨｏｎｇｗｅｉ，ＨｅＦｅｉ，ＸｕＧｅｎｈｕｉ＊，ＭａＸｉｎｂｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＥｎｇｉｎｅｒｉｎｇ，Ｔｉａｎ...

关键词：催化反应双丙酮醇离子交换树脂

Influence of bismuth on magnetism and magnetocaloric properties of Lafe_(11.6)Si_(1.4) intermetallic compound

维普期刊数据库评论

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 2015年第7期33卷 740-745页

作者： A.Boutahar k.Zehani L.Bessais H.Lassri e.k.Hlil LPMMAT Hassan II University-Casablanca Faculty of Science Ain Chock BP 5366 Maarif-Casablanca Morocco ICMPe-CMTR UMR CNRS 7182 2-8 H. Dunant St 94320 Thiais France Néel Institue CNRS and Joseph Fourier University

Crystal structure, magnetic properties and magnetocaloric effects （MCe） of La1-xBixfe1 1.4Si1.6 （x=0.0 and 0.1） compounds were investigated by X-ray diffraction and magnetization measurements. The La1-xBixfe11.4Si1.6 compounds presented a cubic NaZnx3 type structure. First, the magnetization behavior and the magnetic transition were analyzed in terms of Landau theory. Then, Bi substitution for La in La1-xBixfe11.4Si1.6 compounds led to a decrease in magnetic entropy change （-△SM^max） but an increase in Curie temperature （Tc） significantly. The significant increase of Tc by Bi substitution from 202.5 to 256 k for x=0.0 and x=0.1 respectively was attributed to an increase in the fe-fe exchange interactions. Moreover, magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. The maximum values of （-△SM^max ） of La1-xBixfe11.4Si1.6 for x=-0.0 and 0.1 compounds were found to be, respectively, 22.56 and 4.36 J/（kg.k） under an applied magnetic field change of 5 T. For the same applied magnetic field （μ0H=5 T）, the relative cooling power （RCP） values were found to vary between 487 and 296 J/kg.

关键词： NaZn13 itinerant-electron metamagnetic transition magnetocaloric effects rare earths

Free Oxide Distribution in Poorly and Well Drained Soils Developed on Calcareous Alluvial Deposits

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2003年第4期13卷 345-351页

作者： N. k. MOUSTAkAS P. e. BAROUCHAS Agricultural University of Athens Laboratory of Soil Science and Agricultural Chemistry 75 /era Odos Botanikos 11855Agricultural University of Athens Laboratory of Soil Science and Agricultural Chemistry 75 /era Odos Botanikos 11855

A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios feo/fed and (fed-feo)/total fe (fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.

关键词： argillic horizon calcareous alluvial deposits iron oxides manganeseoxides soil homogeneity

Magnetic actuation and transition shapes of a bistable spherical cap

在线全文

学校读者我要写书评

暂无评论

International Journal of Smart and Nano Materials 2014年第4期5卷 270-282页

作者： e.G.Loukaides S.k.Smoukov k.A.Seffena Department of engineering University of CambridgeTrumpington RoadCambridge CB21PZUK Department of Materials Science and Metallurgy University of Cambridge27 Charles Babbage RoadCambridge CB30FSUK

Multistable shells have been proposed for a variety of applications;however,their actuation is almost exclusively addressed through embedded piezoelectric *** actuation techniques are needed for applications requiring high strains or where remote actuation is *** of the reason for the lack of research in this area is the absence of appropriate models describing the detailed deformation and energetics of such *** work presents a bistable spherical cap made of iron carbonyl-infused *** magnetizable structure can be actuated remotely through permanent magnets while the transition is recorded with a high-speed ***,the experiment is reproduced in a finite element(fe)dynamic model for comparison with the physical ***-speed footage of the physical cap inversion together with the fe modeling gives valuable insight on preferable intermediate *** methods return similar values for the magnetic field strength required for the ***-strain multistable spherical cap transformation is demonstrated,based on informed material *** discover that non-axisymmetric transition shapes are preferred in intermediate geometries by bistable spherical *** develop the methods for design and analysis of such actuators,including the feasibility of remote actuation methods for multistable shells.

关键词： multistable composites magnetism actuation

The Petrological and Geochemical evolution of ediacaran Rare-Metal Bearing A-type Granites from the Jabal Aja Complex, Northern Arabian Shield, Saudi Arabia

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(english edition) 2020年第3期94卷 743-762页

作者： Shehta e.ABDALLAH Mokhles k.AZeR Abdullah S.AL SHAMMARI Geology Department Faculty of ScienceZagazig University44519ZagazigEgypt Geological Sciences Department National Research Centre12622 DokkiCairoEgypt Faculty of Science Ha’il University2440 Ha’ilSaudi Arabia

New fieldwork, mineralogical and geochemical data and interpretations are presented for the rare-metal bearing A-type granites of the Aja intrusive complex(AIC) in the northern segment of the Arabian Shield. This complex is characterized by discontinuous ring-shaped outcrops cut by later faulting. The A-type rocks of the AIC are late Neoproterozoic post-collisional granites, including alkali feldspar granite, alkaline granite and peralkaline granite. They represent the outer zones of the AIC, surrounding a core of older rocks including monzogranite, syenogranite and granophyre granite. The sharp contacts between A-type granites of the outer zone and the different granitic rocks of the inner zone suggest that the AIC was emplaced as different phases over a time interval, following complete crystallization of earlier batches. The A-type granites represent the late intrusive phases of the AIC, which were emplaced during tectonic extension, as shown by the emplacement of dykes synchronous with the granite emplacement and the presence of cataclastic features. The A-type granites consist of k-feldspars, quartz, albite, amphiboles and sodic pyroxene with a wide variety of accessory minerals, including fe-Ti oxides, zircon, allanite, fluorite, monazite, titanite, apatite, columbite, xenotime and epidote. They are highly evolved(71.3–75.8 wt% SiO2) and display the typical geochemical characteristics of post-collisional, within-plate granites. They are rare-metal granites enriched in total alkalis, Nb, Zr, Y, Ga, Ta, Ree with low CaO, MgO, Ba, and Sr. eu-negative anomalies(eu/eu* = 0.17–0.37) of the A-type granites reflect extreme magmatic fractionation and perhaps the effects of late fluid-rock interactions. The chemical characteristics indicate that the A-type granites of the AIC represent products of extreme fractional crystallization involving alkali feldspar, quartz and, to a lesser extent, ferromagnesian minerals. The parent magma was derived from the partial melting of

关键词： ring complex rare-metal bearing granites sodic amphibole sodic pyroxene within-plate Arabian Shield

environmental chemical study on the marsh of Fatimid cemetery at Aswan City, egypt

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2002年第4期14卷 464-473页

作者： M.e.Soltan Chemistry Department Faculty of Science

environmental chemical study were carried out on the Fatimid cemetery marsh at Aswan City(24°1'N and 32°9'e), egypt. Marsh contents(warter, soil, sediment, metal and nonmetal bearing salts, and emergent weed) were analysed to known the source of marsh water, speciation of the different elements between the marsh contents, and the toleration of emergent weed (Phargmites australies) for different metals and their bioaccumulation coefficients. Thus, metals(Ca, Mg, Na, k, Ni, fe, Mn, Cu, Zn, Cd and Pb) and nonmetals(CO 2- 3, HCO - 3, Cl -, SO 2- 4, PO 3- 4, NO - 3, SiO 2, organic matter and pH value) were determined in the samples. According to the chemical analysis, and applying the base exchange equation(water type) and calculate the hydrochemical parameters for marsh water samples, we can indicate that the marsh water is ground water with Na SO 4 type and deep meteoric genesis. Topsoil of marsh dry land characterized by CaCl as dominant salt,while NaCl is a dominant salt in subsoil. The elevated pH values of marsh contents minimized the metal solubilities in different samples. Phragmites australies showed a strong ability to accumulate Mn and fe in the aerial part in opposite to Co, Ni and Cd.

关键词： marsh water soil sediment emergent weed egypt

Biochar from grape pomace,a waste of vitivinicultural origin,is effective for root-knot nematode control

在线全文

学校读者我要写书评

暂无评论

Biochar 2023年第1期5卷 519-541页

作者： Ángela Martínez-Gómez Maria fe Andrés Ángel Barón-Sola fernando e.Díaz-Manzano Ibraheem Yousef Ismael F.Mena elena Díaz Óscar Gómez-Torres Azucena González-Coloma Luis e.Hernández Carolina escobar Facultad de Ciencias Ambientales y Bioquímica Universidad de Castilla-La ManchaToledoSpain Departamento de Protección Vegetal Instituto Ciencias Agrarias CSICMadridSpain Departamento de Biología Universidad Autónoma de MadridMadridSpain CeLLS ALBA Carrer del Llum 2-2608290Cerdanyola del VallèsBarcelonaSpain Departamento de Ingeniería Química Universidad Autónoma de MadridMadridSpain Faculty of Chemical Sciences&Technologies Chemical Engineering DepartmentAv.Camilo JoséCela1213071University of Castilla-La ManchaCiudad RealSpain

Root-knot nematodes(RkNs)are obligate endoparasites that feed on their host plants to complete its life cycle,representing a major threat to agriculture and economy *** development of new management strategies becomes essential as effective chemical nematicides are progressively being ***,we analysed grape pomace-derived biochars,pyrolysed at 350℃(BC350)and 700℃(BC700),focusing on their potential for RkN *** thermal treatment of grape pomace caused an increase in the concentration of carbon and plant macro-and micronutrients,which were largely present in a water-soluble *** radiation-based Fourier transform infrared microspectroscopy data showed a general loss of carboxylic functional groups during pyrolysis,partially contributing to the alkalinisation of both biochars,mostly in *** electron microscopy coupled with energydispersive X-ray spectroscopy analysis revealed a highly porous structure filled with different crystals composed of elements such as k,Ca,Mg,P,Si or Al,which could be a suitable environment for the growth of ***-derived aqueous extracts showed phytotoxicity to tomato seedlings at high concentrations,and disappeared upon dilution,but no toxic effect was observed on the nematode’s infective ***,the infective and reproductive traits of a Meloidogyne javanica population in tomato were significantly reduced(*** masses and eggs per plant)in washed-biochar-treated soil in pots(0.75%;BC350W).Therefore,the large amount of grape waste generated after wine production can be transformed into a valuable product such as biochar,effective for RkNs control,thus reducing the waste management problem and contributing to a circular economy.

关键词： Biochar Grape pomace Tomato Root-knot nematode control Meloidogyne spp.