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Science China Mathematics 2024年第3期67卷 627-646页

作者： Hui Xiao ion.grama Quansheng Liu Institut fur Mathematik und Angewandte Informatik Universitat HildesheimHildesheim 31141Germany Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China LMBA Universite Bretagne SudCNRS UMR 6205Vannes F-56000France

Let(g_(n))_(n≥1) be a sequence of independent and identically distributed positive random d×d matrices and consider the matrix product G_(n)=g_(n)…g_*** suitable conditions,we establish the Berry-Esseen bounds on the rate of convergence in the central limit theorem and Cramer-type moderate deviation expansions,for any matrix norm ‖G_(n)‖ of G_(n),its entries G_(n)^(i,j) and its spectral radius ρ(G_(n)).Extended versions of their joint law with the direction of the random walk G_(n)x are also established,where x is a starting point in the unit sphere of R~d.

关键词： Berry-Esseen bound Cramér-type moderate deviation product of random matrices operator norm entry spectral radius

Corrosion Investigation by Scanning Electrochemical Microscopy of AISI 446 and Ti-Coated AISI 446 Ferritic Stainless Steel as Potential Material for Bipolar Plate in PEMWE

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 607-619页

作者： Andrea Kellenberger Nicolae Vaszilcsin Mircea Laurentiu Dan ion Mitelea Alexandru Adrian Geana Sigrid Lædre Corneliu M.Craciunescu Faculty of Industrial Chemistry and Environmental Engineering Politehnica University TimisoaraPiata Victoriei 2300006TimisoaraRomania Faculty of Mechanical Engineering Politehnica University TimisoaraPiata Victoriei 2300006TimisoaraRomania SINTEF Industry 7465TrondheimNorway

The components of proton exchange membrane water electrolysers frequently experience corrosion issues, especially at high anodic polarization, that restrict the use of more affordable alternatives to titanium. Here, we investigate localized corrosion processes of bare and Ti-coated AISI 446 ferritic stainless steel under anodic polarization by scanning electrochemical microscopy (SECM) in sodium sulphate and potassium chloride solutions. SECM approach curves and area scans measured at open-circuit potential (OCP) of the samples in the feedback mode using a redox mediator evidence a negative feedback effect caused by the surface passive film. For the anodic polarization of the sample, the substrate generation-tip collection mode enables to observe local generation of iron (II) ions, as well as formation of molecular oxygen. For the uncoated AISI 446 sample, localized corrosion is detected in sodium sulphate solution simultaneously with oxygen formation at anodic potentials of 1.0 V vs. Ag/AgCl, whereas significant pitting corrosion is observed even at 0.2 V vs. Ag/AgCl in potassium chloride solution. The Ti-coated AISI 446 sample reveals enhanced corrosion resistance in both test solutions, without any evidence of iron (II) ions generation at anodic potentials of 1.2 V vs. Ag/AgCl, where only oxygen formation is observed.

关键词： Ferritic stainless steel Corrosion Ti coating Scanning electrochemical microscopy(SECM) Magnetron sputtering Proton exchange membrane water electrolysis(PEMWE)

Personalized Health Monitoring Systems: Integrating Wearable and AI

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Journal of Intelligent Learning Systems and Applications 2024年第2期16卷 44-52页

作者： ion-Alexandru Secara Dariia Hordiiuk PostureHealth San Francisco CA USA Bidlytics San Francisco CA USA

The integration of wearable technologies and artificial intelligence (AI) has revolutionized healthcare, enabling advanced personal health monitoring systems. This article explores the transformative impact of wearable technologies and AI on healthcare, highlighting the development and theoretical application of the Integrated Personal Health Monitoring System (IPHMS). By integrating data from various wearable devices, such as smartphones, Apple Watches, and Oura Rings, the IPHMS framework aims to revolutionize personal health monitoring through real-time alerts, comprehensive tracking, and personalized insights. Despite its potential, the practical implementation faces challenges, including data privacy, system interoperability, and scalability. The evolution of healthcare technology from traditional methods to AI-enhanced wearables underscores a significant advancement towards personalized care, necessitating further research and innovation to address existing limitations and fully realize the benefits of such integrated health monitoring systems.

关键词： Wearables AI Personalized Healthcare Health Monitoring Systems

Sharp large deviation results for sums of independent random variables

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Science China Mathematics 2015年第9期58卷 1939-1958页

作者： FAN XieQuan grama ion LIU QuanSheng Regularity Team Institut National de Recherche en Informatique et en Automatique Laboratoire de Mathmatiques Appliques aux Systèmes Ecole Centrale Paris-Grande Voie des Vignes Laboratoire de Mathmatiques de Bretagne Atlantique UMR 6205 University Bretagne-Sud School of Mathematics and Computing Science Changsha University of Science and Technology

We show sharp bounds for probabilities of large deviations for sums of independent random variables satisfying Bernstein's condition. One such bound is very close to the tail of the standard Gaussian law in certain case; other bounds improve the inequalities of Bennett and Hoeffding by adding missing factors in the spirit of Talagrand(1995). We also complete Talagrand's inequality by giving a lower bound of the same form, leading to an equality. As a consequence, we obtain large deviation expansions similar to those of Cram′er(1938),Bahadur-Rao(1960) and Sakhanenko(1991). We also show that our bound can be used to improve a recent inequality of Pinelis(2014).

关键词： Bernstein’s inequality sharp large deviations Cramér large deviations expansion of BahadurRao sums of independent random variabl

Determination of Metal Content in Soil and Wheat Plant by Inductively Coupled Plasma Mass Spectrometry

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Journal of Agricultural Chemistry and Environment 2024年第3期13卷 300-311页

作者： Iubu (Badea) Anişoara ion V. Popescu Claudia Stihi Ioana Daniela Dulama Doctoral School of Physics University of Bucharest Magurele Romania Faculty of Science and Arts Valahia University of Targoviste Targoviste Romania Academy of Romanian Scientists Bucharest Romania Institute of Multidisciplinary Research for Science and Technology Valahia University of Targoviste Targoviste Romania

This study aims to investigate the level of soil pollution and the grade of accumulation of metals and heavy metals by wheat plants from the soil in different parts of the crop: root, stem, leaf, spike and grain. Sampling campaigns took place in February, April and July when wheat plants were at different growth stages. A number of eight soil samples and eight wheat plant samples were collected. The sampled wheat plant was taken at the same time and from the same place as the soil. Concentrations of Al (aluminium), Cr (chromium), Mn (manganese), Fe (iron), Ni (nickel), Co (cobalt), Cu (copper), Zn (zinc), Sr (strontium), Cd (cadmium) and Pb (lead) were determined by inductively coupled plasma mass spectrometry. Bioconcentration and translocation factors were calculated for the samples analysed.

关键词： Soil Wheat Plant Heavy Metals Translocation Factor

Prospective study of hepatitis B and D epidemiology and risk factors in Romania:A 10-year update

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World Journal of Hepatology 2024年第4期16卷 640-649页

作者： Speranta Iacob Liana Gheorghe Mirela Onica Laura Huiban Corina Silvia Pop Ciprian Brisc Roxana Sirli Carmen Ester Cristina Mihaela Brisc Sorina Diaconu ion Rogoveanu Larisa Sandulescu Deiana Vuletici Anca Trifan Department of Gastroenterology Carol Davila University of Medicine and PharmacyBucharest 050474Romania Department of Gastroenterology and Hepatology Fundeni Clinical InstituteBucharest 022328Romania Department of Gastroenterology Grigore T Popa University of Medicine and PharmacyIasi 700115Romania Institute of Gastroenterology and Hepatology Saint Spiridon County HospitalIasi 700111Romania Department of Gastroenterology and Medical Oncology University Emergency Clinical HospitalBucharest 050098Romania Faculty of Medicine and Pharmacy University of OradeaOradea 410087Romania Department of Gastroenterology Emergency County HospitalOradea 410169Romania Center for Advanced Research in Gastroenterology and Hepatology Department of Gastroenterology and Hepatology“Victor Babeş”University of Medicine and PharmacyTimisoara 300041Romania Department of Gastroenterology and Hepatology TimişCounty Emergency Clinical Hospital"Pius Branzeu"Timisoara 300723Romania Department of Internal Medicine II and Gastroenterology University Emergency Clinical HospitalBucharest 050098Romania Department of Gastroenterology University of Medicine and PharmacyCraiova 200349Romania Department of Cardiology Emergency County HospitalCraiova 200642Romania Department of Gastroenterology Research Center of Gastroenterology and HepatologyUniversity of Medicine and PharmacyCraiova 200349Romania Department of Gastroenterology Emergency County HospitalCraiova 200642Romania Department of Gastroenterology Faculty of MedicineGrigore T Popa University of Medicine and PharmacyIasi 700115Romania

BACKGROUND The global burden of hepatitis D virus(HDV)infection represents a major medical challenge and a public health crisis ***,there is a lack of accurate data on the epidemiology and risk factors for *** B virus(HBV)and HDV coinfection causes the most severe form of viral hepatitis,leading to a higher cumulative incidence of liver-related events compared with HBV monoinfection,including the need for liver transplantation and *** To investigate the epidemiology,natural history,risk factors and clinical management of HBV and HDV coinfection in Romanian *** This prospective study was conducted between January and July 2022 in six tertiary gastroenterology and hepatology referral centres in *** consecutive adults admitted for any gastroenterology diagnosis who were HBV-positive were *** with acute hepatitis or incomplete data were *** the 25390 individuals who presented with any type of gastroenterology diagnosis during the study period,963 met the inclusion *** for anti-HDV antibodies and HDV RNA was performed for all *** and risk factor data were collected by investigators using medical charts and patient *** data were stored in an anonymized online database during the *** The prevalence of HBV was 3.8%;among these patients,the prevalence of HBV/HDV coinfection was 33.1%.The median age of the study population was 54.0 years,and it consisted of 55.1%men.A higher prevalence of HBV/HDV coinfection was observed in patients 50–69 years *** with HBV/HDV coinfection were significantly older than those with HBV monoinfection(P=0.03).Multivariate multiple regression analysis identified female gender(P=0.0006),imprisonment(Pion among those with HBV re

关键词： Epidemiology Hepatitis B Hepatitis D Natural history Risk factors Romania

Flat limit of the de Sitter QFT in the rest frame vacuum

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Chinese Physics C 2021年第1期45卷 97-108页

作者： ion I.Cotaescu West University of Timisoara V.Parvan Ave.4RO-300223 TimisoaraRomania

The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the frequencies are separated in the rest frames as in special *** is shown that only in the rest frame vacuum can the Minkowskian flat limit be reached naturally fbr any momentum,whereas in the adiabatic vacuum,this limit remains undefined in rest frames in which the momentum *** important role is played by the phases of the fundamental solutions in the rest frame vacuum,which must be regularized to obtain the desired Minkowskian flat *** procedure fixes the phases of the scalar mode functions and Dirac spinors,resulting in their definitive expressions derived *** physical consequenee is that,in the rest frame vacuum,the flat limits of the oneparticle operators are simply the corresponding operators of special relativity.

关键词： de Sitter space-time Klein-Gordon field Dirac field flat limit approximation method phase regularization

Mechanical properties of a Gum-type Ti–Nb–Zr–Fe–O alloy

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 909-917页

作者： Anna Nocivin ion Cinca Doina Raducanu Vasile Danut Cojocaru ion Alexandru Popovici Faculty of Mechanical Industrial and Maritime Engineering Ovidius University of Constanta Faculty of Materials Science and Engineering Politehnica University of Bucharest Carol Davila University of Medicine and Pharmacy

A new Gum-type alloy(Ti–Nb–Zr–Fe–O) in which Fe is used instead of Ta was subjected to a particular thermomechanical processing scheme to assess whether its mechanical characteristics(fine ?-grains with high strength and low modulus) render it suitable as a biomedical implant material. After a homogenization treatment followed by cold-rolling with 50% reduction, the specimens were subjected to one of three different recrystallization treatments at 1073, 1173, and 1273 K. The structural and mechanical properties of all of the treated specimens were analyzed. The mechanical characterization included tensile tests, microhardness determinations, and fractography by scanning electron microscopy. The possible deformation mechanisms were discussed using the Bo – Md diagram. By correlating all of the experimental results, we concluded that the most promising processing variant corresponds to recrystallization at 1073 K, which can provide suitable mechanical characteristics for this type of alloys: high yield and ultimate tensile strengths(1038 and 1083 MPa, respectively), a low modulus of elasticity(62 GPa), and fine crystalline grain size(approximately 50 ?m).

关键词： biomaterials mechanical properties Gum-type alloy thermomechanical processing tensile test

First order QED processes in a spatially flat FLRW space-time with a Milne-type scale factor

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Chinese Physics C 2020年第5期44卷 140-149页

作者： ion ICotaescu Diana Popescu West University of Timisoara V.Parvan Ave.4RO-300223 TimisoaraRomania

The quantum electrodynamics(QED)in a spatially flat(1+3)-dimensional Friedmann-Lema?tre-Robertson-Walker(FLRW)space-time with a Milne-type scale factor is outlined focusing on the amplitudes of the allowed processes in the first order *** definition of the transition rates is reconsidered such that an appropriate angular behavior of the probability for creation of an electron-positron pair from a photon is obtained,which has a similar rate as the creation of a photon and an electron-positron pair from *** is shown that these processes are allowed only in the first order perturbations,since the photon emission or absorption by an electron or positron are forbidden.

关键词： spatially flat FLRW space-time Milne-type scale factor first order amplitudes transition rates

Kinemaitcs in spatially flat FLRW spacetimes

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Chinese Physics C 2021年第10期45卷 92-101页

作者： ion I.Cotäescu West University of Timiäoara

The kinematics on spatially flat FLRW spacetimes is presented for the first time in local charts with physical coordinates,i.e.,the cosmic time and proper Cartesian space coordinates of Painlevé-*** is shown that there exists a conserved momentum that determines the form of the covariant four-momentum on geodesics in terms of physical ***,with the help of this conserved momentum,the peculiar momentum can be defined,thus separating the peculiar and recessional motions without *** is shown that the energy and peculiar momentum satisfy the mass-shell condition of special relativity while the recessional momentum does not produce *** this framework,the measurements of the kinetic quantities along geodesics performed by different observers are analyzed,pointing out an energy loss of the massive particles similar to that producing the photon *** examples of the kinematics on the de Sitter expanding universe and a new Milne-type spacetime are extensively analyzed.

关键词： FLRW specetime peculiar momentum recessional momentum conserved quantities energy loss redshift de Sitter expanding universe Milne-type universe