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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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Catalytic-kinetic spectrophotometric determination of vanadium (V) based on the Celestine blue-bromate-vanadium (V)-citric acid reaction

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Rare Metals 2011年第4期30卷 348-358页

作者： Ramazan gürkan Olcay gürkan Department of Chemistry Faculty of Sciences University of Cumhuriyet Sivas Fen Lisesi Emek mah. 64. Basari Sok. TR-58010 Merkez Sivas TURKEY

A novel sensitive and relatively selective kinetic method is presented for the determination of V（V） based on its catalytic effect on the oxidation reaction of Celestine blue by potassium bromate in the presence of citric acid as an activator. The reaction was monitored spectropho- tometrically by measuring the decrease in absorbance of Celestine blue at a maximum absorption wavelength of 540 nm between 0.5 and 9 min （the fixed-time method） in an H3PO4 medium at 45℃. The effect of various parameters such as concentrations of H3PO4, citric acid, potassium bromate and Celestine blue, ionic strength, reaction temperature and time on the rate of V（V） catalyzed reaction was studied. The method is free from the most interferences, especially from large amounts of V（IV）. The decrease in absorbance is proportional to the concentration of V（V） over the entire concentration range tested （0.025-1.25 ***^-1） with a detection limit of 6.80 tag.L^-1 （according to statistical 3Sblank/k criterion） and a coefficient of variation （CV） of 1.78% （for ten replicate measurements at 95% confidence level）. The proposed method suffers from a few interferences such as Cr（VI） and Hg（Ⅱ） ions. The method was successfully applied to the determination of V（V） in river water, lake water, tap water, natural drinking water samples and a certified standard reference material such as SRM-1640 with satis- factory results. The vanadium contents of natural water samples were detected by using both linear calibration curve and standard addition curve methods. The recoveries of spiked vanadium （V） into the certified standard water sample were found to be quantitative, and the reproducibility was satisfactory. It was observed that the results of the SRM 1640 were in good agreement with the certified value.

关键词： catalytic effect vanadium spectrophotometry bromates Celestine blue citric acid

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Characteristic sites in the internal proteins of avian and human influenza viruses

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Journal of Biomedical Science and Engineering 2010年第10期3卷 943-955页

作者： David King Zachary Miller wesley Jones Wei Hu 不详

The capacity of zoonotic influenza to cross species boundaries to infect humans poses a global health threat. A previous study identified sites in 10 influenza proteins that characterize the host shifts from avian to human influenza. Here, we used seven feature selection algorithms based on machine learning techniques to generate a novel and extensive selection of diverse sites from the nine internal proteins of influenza based on statistically importance to differentiating avian from human viruses. A set of 131 sites was generated by processing each protein independently, and a selection of 113 sites was found by analyzing a concatenation of sequences from all nine proteins. These new sites were analyzed according to their annual mutational trends. The correlation of each site with all other sites (one-to-many) and the connectivity within groups of specific sites (one-to-one) were identified. We compared the performance of these new sites evaluated by four classifiers against those recorded in previous research, and found our sites to be better suited to host distinction in all but one protein, validating the significance of our site selection. Our findings indicated that, in our selection of sites, human influenza tended to mutate more than avian influenza. Despite this, the correlation and connectivity between the avian sites was stronger than that of the human sites, and the percentage of sites with high connectivity was also greater in avian influenza.

关键词： Connectivity Correlation Feature Selection Host Specificity Influenza Machine Learning Mutation

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Influence of earthquake direction on the seismic response of irregular plan RC frame buildings

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 243-256页

作者： Magliulo g Maddaloni g Petrone C University of Naples Federico II Department of Structures for Engineering and Architecture University of Naples Parthenope Department of Engineering

The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismic response of building structures is examined. Three multi-story RC buildings, representing a very common structural typology in Italy, are used as case studies for the evaluation. They are, respectively, a rectangular plan shape, an L plan shape and a rectangular plan shape with courtyard buildings. Nonlinear static and dynamic analyses are performed by considering different seismic levels, characterized by peak ground acceleration on stiff soil equal to 0.35 g, 0.25 g and 0.15 g. Nonlinear dynamic analyses are carried out by considering twelve different earthquake directions, and rotating the direction of both the orthogonal components by 30° for each analysis(from 0° to 330°). The survey is carried out on the L plan shape structure. The results show that the angle of the seismic input motion signifi cantly infl uences the response of RC structures; the critical seismic angle, i.e., the incidence angle that produces the maximum demand, provides an increase of up to 37% in terms of both roof displacements and plastic hinge rotations.

关键词： plan irregularity nonlinear analyses reinforced concrete buildings seismic performance ground motion directionality

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generalized synchronization between different chaotic maps via dead-beat control

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Chinese Physics B 2012年第5期21卷 100-106页

作者： grassi g Dipartimento di Ingegneria dell'Innovazione Università del Salento

This paper presents a new scheme to achieve generalized synchronization（gS） between different discrete-time chaotic（hyperchaotic） *** approach is based on a theorem,which assures that gS is achieved when a structural condition on the considered class of response systems is *** method presents some useful features：it enables exact gS to be achieved in finite time（i.e.,dead-beat synchronization）;it is rigorous,systematic,and straightforward in checking gS;it can be applied to a wide class of chaotic *** examples of gS,including the grassi-Miller map and a recently introduced minimal 2-D quadratic map,are illustrated.

关键词： generalized synchronization chaos synchronization discrete-time chaotic systems deadbeat control chaotic maps

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Structure of low-head two-phase flow in flat nozzlesduring outflow of the liquid into rarefied medium

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航空动力学报 2011年第10期26卷 2188-2192页

作者： Kochenkov A g Tonkonog V g Kazan State Technical University named after A. N. Tupolev Kazan Russian Federation

Outcomes of experimental researches of the low-pressure adiabatic flow of the boiling liquid through two-dimensional Laval nozzles in a vacuum atmosphere were *** of critical conditions of flow were *** forms of a stream were investigated and their connection with crisis of flow was *** was established periodic non-stationary macrostructures of a stream which was stipulated by the rotational gear of origin of a vapor phase.

关键词： component low-head flow flow structure flat nozzle rarefied medium the mechanizm of vaporization mass flow rate

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In-Situ Evaluation of Evaporation in Layered Soils （Tukulu, Sepane and Swartland）

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Journal of Agricultural Science and Technology(A) 2012年第5期2卷 577-590页

作者： Sabelo Sicelo wesley Mavimbela Leon Daniel van Rensburg Department of Soil Crop and Climate Sciences University of the Free State P.O. Box 339 Bloemfontein 9300 South Africa

Knowledge about the influence of soil layers on evaporation is essential for the optimization of infield rainwater harvesting （IRWH） in the semi-arid areas of the Free State province of South Africa. Among the soils earmarked for 1RWH development include the Tukulu, Sepane and Swartland soil types that have contrasting soil layers. These soils have to capture and store rainwater within the soil profile layers away from the evaporation zone. To determine how the three soils release and deliver soil water at the evaporating site, a 21-day evaporation experiment was conducted on pre-drained monoliths. Instantaneous soil water content （SWC） from in-situ and soil water characteristic curve （SWCC） from laboratory was measured. Separate soil samples of 15 mm thickness were also evaporated under the same conditions to establish the extent of drying and hydraulic gradient at the soil surface. The Darcian evaporative flux and unsaturated hydraulic conductivity （K-coefficient） were also determined. At the surface suctions of magnitude greater than 1,500 kPa were observed from all monoliths. Total contributions to evaporation from the Tukulu, Sepane and Swartland were 43, 51 and 70 mm, respectively. The low contributions were explained by the presence of the prismacutanic C-horizon in the Tukulu and Sepane at respective depths of 600 and 700 mm. This layer was associated with the steepest suction gradient that restrained further upward fluxes by subsequent lowering for the K-coefficient with more than two orders of magnitudes within a narrow range of SWC. However, the presence of the pedocutanic B-horizon at depths of 300 mm undermined this restrictive function through the appreciable capillary activity demonstrated by clays at near evaporating surfaces. The shallowness and deficiency in structure of the Swartland was consistent with the high contribution to evaporation that gave this soil a dry soil water regime. It was therefore concluded that the Tukulu offered soil profile

关键词： Soil water soil layers evaporation soil hydraulic characteristics.

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Examining Pet Attitude in Relationship to Loneliness and Parenthood Motivation in Pet-Owning Adults

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Health 2014年第7期6卷 598-606页

作者： Cheryl A. Krause-Parello Yvonne wesley Minnie Campbell College of Nursing Seton Hall University South Orange USA College of Nursing University of Colorado Denver Anschutz Medical Campus Aurora USA Independent Health Consultant Rahway USA

Pets’ growing role in family dynamics creates questions about resources pets may provide in parenthood motivation. Pet ownership has been suggested in the literature as an antecedent to parenthood in terms of developing skills needed to rear offspring, nurturance, and responsibility. Participants (N = 118) who were pet owners, completed an online survey that recorded demographics and consisted of loneliness, pet attitude, and parenthood motivation scales. Results supported that loneliness and pet attitude were positively related to parenthood motivation (all p’s g owners had the most positive attitude. Pets were shown to be a valuable resource in alleviating feelings of loneliness and parenthood preparation in this sample. Implications for nursing practice and future research are discussed.

关键词： Pet Attitude Loneliness Pets Parenthood

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苹果公司、设计及商业操作

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程序员 2010年第7期 68-71页

作者： Bill buxton 微软研究院

1996年12月20日，苹果公司宣布准备收购NeXT公司，1997年2月4日以四亿两千七百万美元的收购价格成交。此次收购，苹果公司至少有两项获益，首先他们获得了能为下一代操作系统提供帮助的技术，其次苹果公司获得了NeXT公司的创始人之一史... 详细信息

1996年12月20日，苹果公司宣布准备收购NeXT公司，1997年2月4日以四亿两千七百万美元的收购价格成交。此次收购，苹果公司至少有两项获益，首先他们获得了能为下一代操作系统提供帮助的技术，其次苹果公司获得了NeXT公司的创始人之一史蒂夫-乔布斯。

关键词：苹果公司操作系统商业设计收购价格 NeXT 创始人

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The European of the Future as a “New Synthesis”: Nietzsche and the Ethnological Task of the West

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Journal of Philosophy Study 2021年第7期11卷 548-576页

作者： Ellen Caroline Vieira de Paiva wesley Leite Feitosa Universidade Federal do Maranhão São LuísBrasil Technische Universität BerlinDeutschland Universidade Federal do Pará BelémBrasil

From a hermeneutic and comparative perspective,the purpose of this paper is to discuss investigative paths of ethnological and ethnographic aspects in Nietzsche’s writings that became relevant for different elaborations of the concept of synthesis in specific thought cycles of his *** a first step,these aspects are verified in his school,philological and philosophical texts,described in relation to his studies on ancient greek culture and compared under the parameter of the different conceptions of synthesis developed by him in each identified ***,the concept of synthesis is discussed as physiology(considering body,consciousness,and language),explaining human life as a creative expression of nature *** this explanation,it becomes possible to understand the processes related to the concept of synthesis as the task of those he terms as good Europeans,and the great politics in his philosophy of the *** identification between the feeling of resistance(Widerstandsgefühl)and the imminence point of the preliminary stage of dominion structures(Herschafts-gebilde)in the last analyzed conception of synthesis is the logical and ethical path towards the demonstration intended *** article concludes by demonstrating the creative and dynamic character of the metaphilosophical scope of the task proposed by him in the mid-1880s and the possibilities opened up from then on for future discussions of culture,aesthetics,knowledge,logic,ethics,and politics.

关键词： good European synthesis ethnology ethnography metaphilosophy

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