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Reproducibility of deposition and industrial applications of stable superhard nanocomposites

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中国有色金属学会会刊：英文版 2004年第z1期14卷 19-24页

作者： stan Veprek Department for Chemistry Technical University Munich Lichtenbergstr. 4 D-85747 Garching b. Munich Germany

After a brief introduction regarding the different approaches to superhard coatings we shall concentrate on the problem of the reproducibility of the deposition of superhard and thermally very stable nanocomposites according to the design principle published by Veprek and Reiprich in 1995. It will be shown that either the choice of inappropriate deposition conditions, in contradiction to our design principle, or impurities in the coatings are the reason for the lack of reproducibility of our earlier results by many other workers. We shall also briefly summarize the recent industrial applications.

关键词： superhard nanocomposite reproducibility of deposition industrial application

OPTIMAL HIERARCHY STRUCTURES FOR MULTI-ATTRIBUTE-CRITERIA DECISIONS

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Journal of Systems Science & Complexity 2009年第2期22卷 228-242页

作者： stan LIPOVETSKY GfK Custom Research North America

A problem of a hierarchy structure optimization is *** structures arewidely used in the Analytic Hierarchy Process,conjoint analysis,and various other methods of multiplecriteria decision *** problem consists in finding a structure that needs a minimum number ofpair comparisons for a given total number of the *** an optimal hierarchy,the minimumefforts are needed for eliciting data and synthesizing the local preferences across the hierarchy to getthe global priorities or *** estimation techniques are developed and numerical *** and numerical results suggest optimal ways of priority evaluations for practicalmanagerial decisions in a complex environment.

关键词： Analytic Hierarchy Process conjoint analysis hierarchy optimization pair comparisons.

Existence of Positive Solutions to Semipositone Singular Dirichlet Boundary Value Problems

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Acta Mathematica Sinica,English Series 2006年第6期22卷 1891-1914页

作者： Svatoslav stan■K Department of Mathematical Analysis Faculty of SciencePalack■University

The paper presents the conditions which guarantee that for some positive value of μ there are positive solutions of the differential equation （Ф（x＇））＇＋μQ（t, x, x＇） = 0 satisfying the Dirichlet boundary conditions x（0） = x（T） = 0. Here Q is a continuous function on the set [0, T] × （0, ∞） ~ （R ／ {0}） of the semipositone type and Q is singular at the value zero of its phase variables.

关键词： existence positive solution semipositone singular problem Dirichlet boundary conditions Ф-Laplacian

Express analysis for prioritization:Best-Worst Scaling alteration to System 1

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Journal of Management Analytics 2020年第1期7卷 12-27页

作者： stan Lipovetsky Minneapolis MinnesotaUSA

The work considers modification of the Best–Worst Scaling(BWS)to the so-called System 1(S1)approach.S1 was described by *** as a spontaneous and automatic reaction by an unconsciousway in which human decision-makers choose among multiple *** of S1 can be seen as a simplified BWS for data eliciting and express analysis of prioritization between many compared *** S1,a respondent picks the items with which she feels“happy”,and those can be one,several,all,or none items in a *** of utilities is performed by multinomial-logit modeling with different optimization criteria which produce parameters of the models and choice probabilities of the *** examples by marketing research data are encouraging and demonstrating that spontaneous choice decisions can make S1 approach very fast,efficient,and convenient for express analysis of items prioritization,especially for big data.

关键词： System 1 BWS max diff MNLutility choice probability prioritization

High temperature oxidation of inoculated high Si/SiMo ductile cast irons in air and combustion atmospheres

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China Foundry 2024年第5期21卷 555-562页

作者： Iuliana stan Mihai Chisamera Robert Lascu Codrut Cariga Eduard Stefan Stelian stan Denisa Anca Iulian Riposan National University of Science and Technology POLITEHNICA Bucharest Materials Science and Engineering Faculty313 Splaiul IndependenteiSector 6060042 BucharestRomania

The present work aims to investigate the effect of heating temperature(400,600 and 800°C)and inoculating elements(Ca,Ca-Ba,Ca-RE)on oxidation behavior of ductile irons containing 5.25%Si and 4.8%Si-2.3%Mo in dry air and combustion gas containing water vapour(natural gas burning).The oxidation is influenced by the gas atmosphere type,the iron alloying system,and the inoculating elements depending on the heating *** weight gain increases from 0.001%-0.1%(400°C)to 0.05%-0.70%(600°C)and up to 0.10%-2.15%(800°C).No particular effects of the considered influencing factors are found when heating at 400°C,while at 600°C,mainly the oxidation gas atmosphere type shows a visible *** the highest heating temperature of 800°C,a limited increase of the weight gain is found for dry air atmosphere(up to 0.25%),but it drastically increases for combustion atmospheres(0.65%-2.15%).The water vapour presence in the combustion atmosphere is an important oxidising factor at 600-800°*** alloying system appears to influence the oxidation behavior mainly at a heating temperature of 800°C in the combustion atmosphere,as evidenced by the lower weight gain in 5.25%silicon cast *** effects of inoculating elements increase with the heating temperature,with Ca and Ba-FeSi inoculation generally showing better *** inoculated with CaRE-FeSi exhibit a higher degree of *** results are in good relationship with the previous reported data:Ca-Ba-inoculation system appears to be better than simple Ca for improving the graphite parameters,while RE-bearing inoculant negatively affects the compactness degree of graphite particles in high-Si ductile *** the lower compactness degree is typical for graphite nodules in high-Si ductile irons,which negatively affects the oxidation resistance,it is necessary to employ specific metallurgical treatments to improve nodule ***,in particular,is a potential method to achieve this improvement.

关键词： ductile iron spheroidal graphite Si/SiMo oxidation air/combustion atmospheres FeSiCaMgRE treatment Ca,Ca-Ba,Ca-RE inoculation structure characteristics

Recognition of rock anisotropy using integrated seismic approach-A case in Strzegom and Podlesna,Poland

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第7期15卷 1759-1767页

作者： Iwona stan-Kłeczek Artur Marciniak University of Silesia Faculty of Natural SciencesSosnowiecPoland Institute of Geophysics of Polish Academy of Sciences WarsawPoland

This paper presents the integration of seismic refraction and multichannel analysis of surface wave(MASW)measurements to investigate the anisotropy of P-and S-wave ***,synthetic forward modelling is presented as a tool for supporting seismic anisotropy *** geophysical measurements of cracks allowed to recognise the fracturing of a granite rock mass in a Paleozoic granite quarry(Strzegom,Poland)and a dolomite rock mass in a Triassic dolomite quarry(Podlesna,Poland).Application of the forward modelling supports the interpretation of seismic methods,simplifying data processing and verifying the final results based on data from difficult seismic *** a result of direct measurements,two crack systems were determined in granite rock mass:NNE-SSW and NNW-SSE,and two in dolomite rock mass:NNE-SSW and ***,the numerical results show the relationship between the highest values of P-and S-wave velocities and separated crack systems which allowed an unequivocal interpretation of the direction of stress,resulting in the *** obtained information is promising to be helpful in mining exploration for optimising excavation works.

关键词： Fracturing Anisotropy Seismic refraction Multichannel analysis of surface wave(MASW) Forward modelling

Performance of heavy ductile iron castings for windmills

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China Foundry 2010年第2期7卷 163-170页

作者： Iulian Riposan Mihai Chisamera Stelian stan POLITEHNICA University of Bucharest 313 Spl.Independentei RO-060042 BucharestRomania

The main objective of the present paper is to review the specific characteristics and performance obtaining conditions of heavy ductile iron(DI) castings,typically applied in windmills industry,such as hubs and rotor *** requirements for high impact properties in DI at low temperatures are part of the ENGJS-400-18U-LT(SRN 1563) commonly referred to as GGG 40.3(DIN 1693).Pearlitic in-uence factor(Px) and antinodularising action factor(K1) were found to have an important in-uence on the structure and mechanical properties,as did Mn and P content,rare earth(RE) addition and inoculation *** presence of high purity pig iron in the charge is extremely beneficial,not only to control the complex factors Px and K1,but also to improve the 'metallurgical quality' of the iron melt.A correlation of C and Si limits with section modulus is very important to limit graphite nodule *** and surface-degenerated graphite are the most controlled graphite morphologies in windmills *** paper concluded on the optimum iron chemistry and melting procedure,Mg-alloys and inoculants peculiar systems,as well as on the practical solutions to limit graphite degeneration and to ensure castings of the highest integrity,typically for this field.

关键词： heavy ductile iron castings windmills parts chemistry structure treatments control

A review:applications of the phase field method in predicting microstructure and property evolution of irradiated nuclear materials

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npj Computational Materials 2017年第1期3卷 333-349页

作者： Yulan Li Shenyang Hu Xin Sun Marius stan Pacific Northwest National Laboratory 902 Battelle BoulevardRichlandWA 99352USA Argonne National Laboratory 9700 South Cass AvenueLemontIL 60439USA

Complex microstructure changes occur in nuclear fuel and structural materials due to the extreme environments of intense irradiation and high *** paper evaluates the role of the phase field method in predicting the microstructure evolution of irradiated nuclear materials and the impact on their mechanical,thermal,and magnetic *** paper starts with an overview of the important physical mechanisms of defect evolution and the significant gaps in simulating microstructure evolution in irradiated nuclear ***,the phase field method is introduced as a powerful and predictive tool and its applications to microstructure and property evolution in irradiated nuclear materials are *** review shows that(1)Phase field models can correctly describe important phenomena such as spatial-dependent generation,migration,and recombination of defects,radiation-induced dissolution,the Soret effect,strong interfacial energy anisotropy,and elastic interaction;(2)The phase field method can qualitatively and quantitatively simulate two-dimensional and three-dimensional microstructure evolution,including radiation-induced segregation,second phase nucleation,void migration,void and gas bubble superlattice formation,interstitial loop evolution,hydrate formation,and grain growth,and(3)The Phase field method correctly predicts the relationships between microstructures and *** final section is dedicated to a discussion of the strengths and limitations of the phase field method,as applied to irradiation effects in nuclear materials.

关键词： properties irradiated phase

Revealing the Pressure-Induced Softening/Weakening Mechanism in Representative Covalent Materials

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Chinese Physics Letters 2021年第5期38卷 51-59页

作者： Tengfei Xu Shihao Zhang Dominik Legut stan Veprek Ruifeng Zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China Center for Integrated Computational Engineering(International Research Institute for Multidisciplinary Science)and Key Laboratory of High-Temperature Structural Materials&Coatings Technology(Ministry of Industry and Information Technology) Beihang UniversityBeijing 100191China IT4Innovations VSB-Technical University of Ostrava17 listopadu 2172/1570800 OstravaCzech Republic Department of Chemistry Technical University MunichLichtenbergstr 4D-85747 GarchingGermany

Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively *** is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials.

关键词： red service Revealing the Pressure-Induced Softening/Weakening Mechanism in Representative Covalent Materials