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Comparative Assessment of Phytochemicals, Proximate and Elemental Composition of <i>Gnetum africanum</i>(okazi) Leaves

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American Journal of Analytical Chemistry 2015年第7期6卷 604-609页

作者： I. o. okerulu C. T. onyema Department Pure and Industrial Chemistry Nnamdi Azikiwe University Awka Nigeria

The leaves of Gnetum africanum were studied for their proximate (nutrient), mineral (elemental) and phytochemical constituents. All analyses were done using standard analytical procedures and the results obtained showed a moisture content, crude protein, ash content, crude fibre, crude lipids and carbohydrates of 10.9%, 20.12%, 6.70%, 7.10%, 2.79% and 52.39% respectively. The mineral (elemental) analysis showed the presence of sodium, magnessium, calcium, iron, zinc, manganesse, potassium and copper in that order of decreasing concentration while notably absent was chromium and lead in the examined leaves. The phytochemicals detected in the leaves using various selected solvents were alkaloids, saponins, glycosides and tannins with various concentrations while flavonoids, phenols and steroids were totally absent. From the results of the aforementioned analyses, it could be concluded that the leaves of Gnetum africanum contain some beneficial nutrients, mineral elements and secondary metabolites justifying the medicinal status and possible potency of the plant part.

关键词： Gnetum africanum Leaves Phytochemicals Proximate and Elemental Compositions

Application of a new reagent for analysis of oxygen presence in a lowcarbon steel wire rod

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Journal of Iron and Steel Research International 2021年第6期28卷 729-738页

作者： M.I.Dávila-Pérez H.J.Vergara-Hernández o.Vázquez-Gómez F.Reyes-Calderón E.López-Martínez J.M.Salgado-López National Technology of Mexico/T.I.of Morelia Morelia 58120MichoacanMexico National Council for Science and Technology CoNACYT Mexico City 03940Mexico Isthmus University Santo Domingo TehuantepecOaxaca 70760Mexico Engineering and Industrial Development Center CIDESI Santiago de Queretaro 76125QueretaroMexico

A microstructural analysis was performed to determine the presence of oxygen in a wire rod section of AISI 1008 steel with a surface mechanical failure produced during wire *** failure zone was analyzed by comparison using three different attack reagents:alkaline sodium chromate(ASC),ASC with hydrogen peroxide and amyl alcohol,and a solution of nitric acid in ethyl *** reagents were applied in samples in the failure zone,showing different types of zones in regions with internal and superficial defects such as carbides,pores,cracks,deformation,and detachment zones,indicating the possible presence of *** areas identified were observed by means of an optical microscope and were correlated with the content of elements that were present in the region using a scanning electron microscope and a scattered X-ray energy spectrometer,which determined that the areas identified by chromate sodium correspond to regions with a high concentration of oxygen and slag-forming elements such as silicon,aluminum,and iron;this is associated with the presence of oxygen in the oxide *** was also observed that the ASC and the modified ASC solution with hydrogen peroxide and amyl alcohol could identify areas with a high presence of oxides,while the nitric acid solution only identified the steel *** modified ASC solution is an alternative to identify the presence of chemical variants of oxygen because the conventional formulation is unstable and has a too short shelf life,and therefore,its application must be carried out at the time of preparation.

关键词： Etching Alkaline sodium chromate oxide presence Internal defect

ZUR STRATIGRAPHIE DES MINUSSINISCHEN PALAoZoIKUM

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地质学报 1935年第1期 93-98页

作者： VoN R.I.VIALoVA UND o.S.VIALoV

Whrend der geologischen Forschungen welche im Jahre 1930 imBezirk Atschinsk des Minussinischen Gebiets (Westsibirien) von ***ührt wurden,haben wir einige für die Stratigraphie ziemlich interessanteFunde gemacht.

关键词： der ZUR STRATIGRAPHIE DES MINUSSINISCHEN PALAoZoIKUM

In situ observation of synthesized nanoparticles in ultra-dilute aerosols via X-ray scattering

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Nano Research 2019年第1期12卷 25-31页

作者： Sarah R.McKibbin Sofie Yngman olivier Balmes Bengt o.Meuller Simon Tagerud Maria E.Messing Giuseppe Portale Michael Sztucki Knut Deppert Lars Samuelson Martin H.Magnusson Edvin Lundgren Anders Mikkelsen Department of Physics and Nanolund Lund UniversityBox 11822100 LundSweden MaxIV Laboratory Lund UniversityBox 11822100 LundSweden University of Groningen Zemike Institute for Advanced MaterialsNijenborgh 4NL-9747 AG GroningenThe Netherlands ESRF-The European Synchrotron CS 4022038043 Grenoble Cedex 9France

In-air epitaxy of nanostructures(Aerotaxy)has recently emerged as a viable route for fast,large-scale *** this study,we use small-a ngle X-ray scatteri ng to perform direct in-flight characterizati ons of the first step of this process,i.e.,the en gineered formatio n of Au and Pt aerosol nan oparticles by spark gen erati on in a flow of N2 *** represe nts a particular challe nge for characterizati on because the particle density can be extremely low in con trolled *** particles produced are exami ned duri ng producti on at operatio nal pressures close to atmospheric conditions and exhibit a log no rmal size distributi on ranging from *** Au and Pt particle productio n and detection are *** observe and characterize the nanoparticles at different stages of synthesis and extract the corresponding domi nant physical properties,in cludi ng the average particle diameter and sphericity,as in flue need by particle sintering and the prese nee of *** observe highly sorted and sin tered spherical Au nano particles at ultra-dilute concen tratio ns(orresponding to a volume fraction below 3×10^-10,which is orders of magnitude below that of previously measured *** independently confirm an average particle radius of 25 nm via Guinier and Kratky plot *** study indicates that with high-intensity synchrotron beams and careful con sideratio n of backgro und removal,size and shape info rmati on can be obtai ned for extremely low particle concentrations with industrially relevant narrow size distributions.

关键词： aerosol nanoparticle synthesis in situ analysis small-angle X-ray scattering Aerotaxy

铝合金上电沉积Ni-P-CNTs复合镀层及其摩擦性能研究

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浙江大学学报（工学版） 2008年第11期42卷 2033-2036页

作者：陈卫祥涂江平王浪云王玉琮刘新宽 CHARLS o L K 浙江大学化学系浙江杭州310027 浙江大学材料科学与工程学系浙江杭州310027 美国通用汽车公司表面工程与摩擦中心美国华盛顿特区

采用复合电沉积法在铝合金表面上制备了镍-磷-碳纳米管(Ni-P-CNTs)复合镀层,并用X射线衍射(XRD)和扫描电镜(SEM)对其进行了表征,分析了电流密度和镀液中碳纳米管的质量浓度对复合镀层形貌及其摩擦磨损性能的影响.当电流密度为3.0 A/dm2... 详细信息

采用复合电沉积法在铝合金表面上制备了镍-磷-碳纳米管(Ni-P-CNTs)复合镀层,并用X射线衍射(XRD)和扫描电镜(SEM)对其进行了表征,分析了电流密度和镀液中碳纳米管的质量浓度对复合镀层形貌及其摩擦磨损性能的影响.当电流密度为3.0 A/dm2时可以得到表面光亮、平整的复合镀层,复合镀层中碳纳米管体积分数随着镀液中碳纳米管质量浓度的增加而增加.Ni-P-CNTs复合镀层比Ni-P镀层具有更高的硬度、耐磨性能和更低的摩擦系数.随着复合镀层中碳纳米管体积分数的增加,复合镀层的磨损量和摩擦系数逐渐降低.复合镀层摩擦性能的改善是由于碳纳米管具有优异的力学性能和良好的自润滑性能.

关键词：复合电沉积碳纳米管复合镀层摩擦磨损铝合金

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An Algebra of ontologies Approximation under Uncertainty

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International Journal of Intelligence Science 2014年第2期4卷 54-64页

作者： A. F. Donfack Kana B. o. Akinkunmi Department of Mathematics Ahmadu Bello University Zaria Nigeria partment of Computer Science University of Ibadan Ibadan Nigeria

ontologies are widely used in modeling the real world for the purpose of information sharing and reasoning. Traditional ontologies contain only concepts and relations that describe asserted facts about the world. Modeling in a dynamic world requires taking into consideration the uncertainty that may arise in the domain. In this paper, the concept of soft sets initiated by Molodtsov and the concept of rough sets introduced by Pawlack are used to define a way of instantiating ontologies of vague domains. We define ontological algebraic operations and their properties while taking into consideration the uncertain nature of domains. We show that, by doing so, intra ontological operations and their properties are preserved and formalized as operations in a vague set of objects and can be proved algebraically.

关键词： ontologies Description Logics Soft Sets Rough Sets Uncertainty

Blade Parameterization and Aerodynamic Design optimization for a 3D Transonic Compressor Rotor

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Journal of Thermal Science 2007年第2期16卷 105-114页

作者： Naixing Chen Hongwu Zhang Yanji Xu Weiguang Huang Institute of Engineering Thermophysics,Chinese Academy of Sciences,P.o.Box 2706,Beijing 100080,CHINA.E-mail:nxc@*** Fax:+8610-62573335 Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China

The present paper describes an optimization methodology for aerodynamic design of turbomachinery combined with a rapid 3D blade and grid generator （RAPID3DGRID）, a N.S. solver, a blade parameterization method （BPM）, a gradient-based parameterization-analyzing method （GPAM）, a response surface method （RSM） with zooming algorithm and a simple gradient method. By the use of blade parameterization method a transonic com- pressor rotor can be expressed by a set of polynomials, and then it enables us to transform coordinate-expressed blade data to parameter-expressed and then to reduce the number of parameters. With changing any one of the parameters and by applying grid generator and N.S. solver, we can obtain several groups of samples. Here only ten parameters were considered to search an optimized compressor rotor. As a result of optimization, the adiabatic efficiency was increased by 1.73%.

关键词： Aerodynamic optimization blade optimization compressor bladings

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Effect of High Temperature Treatment on Aqueous Corrosion of Low-Carbon Steel by Electrochemical Impedance Spectroscopy

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Materials Sciences and Applications 2011年第2期2卷 81-86页

作者： Samuel J. Gana Nosa o. Egiebor Ramble Ankumah 不详

The corrosion behavior of 1020C carbon steel samples that had been subjected to oxidizing heat treatment at 550°C and 675°C were studied in sodium chloride electrolytes using a 3-electrode electrochemical impedance spectroscopy. Experimental data were used to evaluate the corrosion behavior of the samples while optical microscopy was employed to investigate the surface characteristics of the samples before and after aqueous corrosion. The results showed that while the sample treated at 550°C revealed an increasing corrosion rate with time, the sample treated at 675°C indicated a higher initial corrosion rate, but the rate declined gradually over the 4-day experimental period. optical microscopy revealed significant formation of surface corrosion products on both heat treated samples, but the complex plane diagrams indicated significant capacitive behavior for the heat treated samples relative to the untreated samples.

关键词： Impedance Carbon Steel Corrosion Nyquist Diagrams Photomicrographs

Perception and Information Seeking Behaviour of Rural Households towards Health Promoting Practices in Maigana District of Kaduna State, Nigeria

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open Journal of Medical Psychology 2017年第4期6卷 233-242页

作者： C. C. Ezeh o. H. Ezeh College of Agriculture Ahmadu Bello University Zaria Nigeria Department of Community Medicine Ahmadu Bello University Zaria Nigeria

Information is valuable, increases understanding and reduces uncertainty. Limited knowledge and access to health promoting and disease prevention programmes are more pronounced in rural than urban areas of Nigeria. Furthermore, the paucity of healthcare services in these rural communities also contributes to the prevalence of health challenges in the rural sector. This study investigated the perception and information seeking behavior of rural households in Maigana District of Kaduna State, Nigeria towards health promoting practices. A random sample of 152 respondents selected from five of eleven wards in the district was interviewed using a pre-tested structured questionnaire. The results, based on a 4-point Likert type scale and benchmark of 2.5 showed a very poor perception of health promoting practices among the respondents. Also, the information needs of the respondents were shown to be enormous. Three of the six socio-demographic variables regressed were found to significantly influence the information seeking behavior of the respondents regarding health promoting practices. Constraints limiting the embracement of health promoting practices were identified and measures aimed at promoting healthier living standards in rural communities were recommended. The study concludes that vast knowledge gaps do exist coupled with the poor perception of HPPs by the respondents.

关键词： Perception Information Health Promoting Rural Households