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Cuboidal vs equiaxed:The role of nanopowder assembly during BaTiO_(3)ceramic pressing step

Journal of Materials Science & Technology 2024年第22期189卷 13-24页

作者： Vlad Alexandru Lukacs radu stirbu Oana Andreea Condurache Lavinia Petronela Curecheriu Mirela Airimioaei Cristina Elena Ciomaga George Stoian Gabriel Caruntu Liliana Mitoseriu Maria Teresa Buscaglia Dielectrics Ferroelectrics&Multiferroics GroupFaculty of Physics“Al.I.Cuza”University of Iasi11 Carol I Bv.700506 IasiRomania Electronic Ceramics Department Jozef Stefan InstituteLjubljana 1000Slovenia Faculty of Chemistry “Al.I.Cuza”University of Iasi11 Carol I Bv.700506 IasiRomania Department of Exact and Natural Sciences Institute of Interdisciplinary Research“Al.I.Cuza”University of Iasi11 Carol I Bv.700506 IasiRomania National Institute of Research and Development for Technical Physics 700050 IasiRomania Departement of Chemistry&Biochemistry Central Michigan UniversityMount PleasantMI 48859United States Institute of Condensed Matter Chemistry and Technologies for Energy CNRVia de Marini 616149 GenoaItaly

The functional properties of BaTiO_(3)ceramics,produced by using the same pressing/sintering strategy from nanopowders with two distinct morphologies(cuboidal/equiaxed nanoparticles)and similar particle sizes,are comparatively *** sintered ceramics exhibit similar nanoscale structures,with faceted crystalline grains and crystalline inclusions,clean grain boundaries and well-defined 90°lamellar domains extending in some entire grains or finer nanodomains inside grain *** differences in the functional behavior originating from the different nanopowder morphology are described in terms of the nanoparticle assembly during the pressing *** numerically simulated green body densification indicated a more efficient assembly resulting in higher density for the cubic particles(0.90 vs.0.84 relative density)and a more homogeneous pore distribution in the spherical-derived *** a result of the higher density after sintering,the functional properties are enhanced in cuboid-originated *** comparison,the ceramic produced from cubic nanoparticles sintered at T_(1)/T_(2)=1250/800℃shows higher permittivity(room temperature value of∼2100-cubic vs.∼1700-rounded),enhanced ferroelectric characteristics(cubic:P_(s)=8.57μC cm^(-2),P_(r)=0.95μC cm^(-2),and E_(c)=2.3 kV cm^(-1),with respect to P_(s)=6.06μC cm^(-2),P_(r)=0.4μC cm^(-2),and E_(c)=1.4 kV cm^(-1),for spherical-derived ones,measured at E_(max)=29.3 kV cm^(-1))and a stronger dc-field dependence of their permittivity of∼12%(cubic)***∼2%(spherical),for a dc-applied field in the range of-15 kV cm^(-1)

关键词： Electroceramics Pressing Morphology Compaction BaTiO_(3)

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Energy balance model to assess the resistance of ballistic protection materials

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Defence Technology（防务技术） 2023年第12期30卷 141-153页

作者： Bogdan stirbu Irene Ndindabahizi Tom Vancaeyzeele Cyril Robbe Department of Weapon Systems and Ballistics Royal Military AcademyBrussels 1000Belgium

NATO standards"AEP-2920 Procedures for the Evaluation and Classification of Personal Armor"and NIJ Standard-0101.06,indicate the method to statistically assess the resistance of personal ballistic protection *** be validated and accepted through these procedures,a personal ballistic protection material should withstand an impact of a specific projectile with a probability of a partial penetration confidence level higher than 90%.The present study introduces an energy equilibrium method to assess the confidence level for the probability of partial penetration of ductile and brittle *** experiments performed in the Ballistics laboratory of the Royal Military Academy in Belgium,use a modified pendulum method that allowed the quantification of the energy balance before and after the ballistic *** results were then compared with the ones obtained using the method specified by the NATO standard and NIJ 0101.06,mentioned *** outcome of this comparison shows the tendency of the values obtained by the pendulum method to faithfully follow the values obtained according to NATO and NIJ *** presented method is not based on statistical estimations,but instead,an exact method,of computing the energy absorbed by the tested *** is an advantage for the cases when the material to be evaluated is expensive or it is in the development phase and mass production is not possible.

关键词： Energy NATO Ballistic Protection materials Statistics NIJ Bootstrapping

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A semiclassical perspective on nuclear chirality

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Frontiers of physics 2024年第2期19卷 39-52页

作者： radu Budaca “Horia Hulubei”National Institute for R&D in Physics and Nuclear Engineering Str.Reactorului 30RO-077125POB-MG6 Bucharest-MǎgureleRomania Academy of Romanian Scientists Splaiul Independenţei 54050044BucharestRomania

The application of the semiclassical description to a particle-core system with imbued chiral symmetry is *** classical features of the chiral geometry in atomic nuclei and the associated dynamics are investigated for various core deformations and single-particle *** dynamical characteristics are identified in specific angular momentum ranges,triaxiality and alignment *** observables will be extracted from the classical picture for a quantitative description of experimental data provided as numerical examples of the model’s performance.

关键词： chiral symmetry triaxial nuclei semiclassical description

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Modelling of internal ballistics of gun systems:A review

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Defence Technology（防务技术） 2024年第11期41卷 35-58页

作者： F.Ongaro C.Robbe A.Papy B.stirbu A.Chabotier Royal Military Academy Avenue de la Renaissance 30Bruxelles 1000Belgium

A deep understanding of the internal ballistic process and the factors affecting it is of primary importance to efficiently design a gun system and ensure its safe management. One of the main goals of internal ballistics is to estimate the gas pressure into the combustion chamber and the projectile muzzle velocity in order to use the propellant to its higher efficiency while avoiding over-pressure phenomena. Dealing with the internal ballistic problem is a complex undertaking since it requires handling the interaction between different constituents during a transient time lapse with very steep rise of pressure and temperature. Several approaches have been proposed in the literature, based on different assumptions and techniques. Generally, depending on the used mathematical framework, they can be classified into two categories: computational fluid dynamics-based models and lumped-parameter ones. By focusing on gun systems, this paper offers a review of the main contributions in the field by mentioning their advantages and drawbacks. An insight into the limitations of the currently available modelling strategies is provided,as well as some considerations on the choice of one model over another. Lumped-parameter models, for example, are a good candidate for performing parametric analysis and optimisation processes of gun systems, given their minimum requirements of computer resources. Conversely, CFD-based models have a better capacity to address more sophisticated phenomena like pressure waves and turbulent flow effects. The performed review also reveals that too little attention has been given to small calibre guns since the majority of currently available models are conceived for medium and large calibre gun ***, aspects like wear phenomena, bore deformations or projectile-barrel interactions still need to be adequately addressed and our suggestion is to dedicate more effort on it.

关键词： Internal ballistics Numerical modelling Lumped-parameter model Computational fluid dynamics Gun systems

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Evaluation of the seismic hazard for 20 cities in Romania using Monte Carlo based simulations

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Earthquake Engineering and Engineering Vibration 2017年第3期16卷 513-523页

作者： Florin Pavel radu Vacareanu Seismic Risk Assessment Research Center Technical University of Civil Engineering Bucharest Romania

This work focuses on the evaluation of the seismic hazard for Romania using earthquake catalogues generated by a Monte Carlo approach. The seismicity of Romania can be attributed to the Vrancea intermediate-depth seismic source and to 13 other crustal seismic sources. The recurrence times of large magnitude seismic events（both crustal and subcrustal）, as well as the moment release rates are computed using simulated earthquake catalogues. The results show that the largest contribution to the overall moment release for the crustal seismic sources is from the seismic regions in Bulgaria, while the seismic regions in Romania contribute less than 5% of the overall moment release. In addition, the computations show that the moment release rate for the Vrancea subcrustal seismic source is about ten times larger than that of all the crustal seismic sources. Finally, the Monte Carlo approach is used to evaluate the seismic hazard for 20 cities in Romania with populations larger than 100,000 inhabitants. The results show some differences between the seismic hazard values obtained through Monte-Carlo simulation and those in the Romanian seismic design code P100-1/2013, notably for cities situated in the western part of Romania that are influenced by local crustal seismic sources.

关键词： seismic sources uncertainty seismic moment GMPE percentile

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Investigation on regional attenuation of Vrancea (Romania) intermediate-depth earthquakes

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Earthquake Engineering and Engineering Vibration 2018年第3期17卷 501-509页

作者： Florin Pavel radu Vacareanu Seismic Risk Assessment Research Center Technical University of Civil Engineering

This paper aims at investigating possible regional attenuation patterns in the case of Vrancea（Romania） intermediate-depth *** 500 pairs of horizontal components recorded during 13 intermediate-depth Vrancea earthquakes are employed in order to evaluate the regional attenuation *** recordings are grouped according to the azimuth with regard to the Vrancea seismic source and subsequently,Q models are computed for each azimuthal zone assuming similar geometrical ***,the local soil amplification which was disregarded in a previous analysis performed for Vrancea intermediate-depth earthquakes is now clearly *** results show minor differences between the four regions situated in front of the Carpathian Mountains and considerable differences in attenuation of seismic waves between the forearc and backarc regions（with regard to the Carpathian Mountains）.Consequently,an average Q model of the type Q（f） = 115×f^1.25 is obtained for the four forearc regions,while a separate Q model of the type Q（f） = 70×f^0.90 is computed for the backarc *** results highlight the need to evaluate the seismic hazard of Romania by using ground motion models which take into account the different attenuation between the forearc/backarc regions.

关键词： Fourier amplitude spectrum azimuth dependency source-to-site distance Q model local soil conditions

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Autologous cord blood vs individualized supplements in autistic spectrum disorder:CORDUS study results

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World Journal of Clinical Pediatrics 2025年第1期14卷 101-112页

作者： Felician A Stancioiu Raluca Bogdan Bogdan Ivanescu radu Dumitrescu Department of Clinical Research Bio-Forum FoundationBucharest 040245BucurestiRomania Department of Pediatrics Medicover Hospital BucharestBucharest 013982BucurestiRomania Doctor MiT Clinic Bucharest 013929BucurestiRomania Department of Anesthesiology and Intensive Therapy Medicover HospitalBucharest 013982BucurestiRomania

BACKGROUND Cellular therapies have started an important new therapeutic direction in autistic spectrum disorder(ASD),and the ample diversity of ASD pathophysiology and the different types of cell therapies prompt an equally ample effort to employ clinical studies for studying the ASD causes and cell *** cells have yielded so far mixed results in clinical trials,and at patient level the results varied from impressive to no *** this context we have administered autologous cord blood(ACB)and a non-placebo,material intervention repre-sented by an individualized combination of supplements(ICS)to ASD *** CORDUS clinical study is a crossover study in which both oral ICS and intravenous ACB were sequentially administered to 56 children;ACB was infused as an inpatient *** efficacy was evaluated pre-treatment and post-treatment at 6 months by an independent psychotherapist with Autism Treatment Evaluation Checklist,Quantitative Checklist for Autism in Toddlers and a 16-item comparative table score,after interviewing the children’s parents and *** and after each intervention participants had a set of blood tests including inflammatory,metabolic and oxidative markers,and the neuronal specific *** No serious adverse reactions were noted during and after cord blood or supplement *** improved evaluation scores in 78%of children with age 3–7-years(n=28),but was much less effective in kids older than 8 years or with body weight of more than 35 kg(n=28;only 11%of children improved scores).ICS yielded better results than ACB in 5 cases out of 28,while in 23 kids ACB brought more improvement than ICS(P<0.05);high initial levels of inflammation and ferritin were associated with no *** individual differences were noted in children's progress,and statistically significant improvements were seen after ACB on areas such as verbalization and social interaction,but not on irritability or

关键词： Autistic spectrum disorder Cord blood Stem cells Neuroinflammation Autologous stem cell treatment Neuronal specific enolase

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Expectation-maximisation for speech source separation using convolutive transfer function

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CAAI Transactions on Intelligence Technology 2019年第1期4卷 47-53页

作者： Xiaofei Li Laurent Girin radu Horaud INRIA Grenoble Rhoe-Alpes Montbonnot Saint-MartinFrance GIPSA-lab Saint-Martin d’HèresFrance UniversitéGrenoble Alpes Saint-Martin d’HèresFrance

This study addresses the problem of under-determined speech source separation from multichannel microphone signals,*** convolutive mixtures of multiple *** time-domain signals are first transformed to the short-time Fourier transform(STFT)*** represent the room filters in the STFT domain,instead of the widely used narrowband assumption,the authors propose to use a more accurate model,*** convolutive transfer function(CTF).At each frequency band,the CTF coefficients of the mixing filters and the STFT coefficients of the sources are jointly estimated by maximising the likelihood of the microphone signals,which is resolved by an expectation-maximisation *** show that the proposed method provides very satisfactory performance under highly reverberant environments.

关键词： STFT CTF

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Learning tasks as a possible treatment for DNA lesions induced by oxidative stress in hippocampal neurons

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Neural Regeneration Research 2013年第32期8卷 3063-3070页

作者： Dragos Cīrneci radu Silaghi-Dumitrescu Brain Research Institute Synergon Consulting Faculty of Chemistry and Chemical Engineering Babes-Bolyai University

Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc- tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path- ways to counteract these effects, with base excision repair being responsible for repairing one of the major base lesions （8-oxoG） in all organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer＇s dis- ease-like disease, but given its complexity it is not clear what specific aspect of enriched environ- ment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of base excision repair. Based on the evidence, we propose that learning tasks such as novel object recognition could be tested as possible methods of base excision repair fa- cilitation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effec- tive, it could be the start for designing similar tasks for humans, as a behavioral therapeutic com- plement to the classical drug-based therapy in treating neurodegenerative disorders.

关键词： neural regeneration reviews neurodegenerative disorder reactive oxygen species base excisionrepair cognitive stimulation p300 grants-supported paper neural regeneration

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Bi-normalized response spectra and seismic intensity in Bucharest for 1986 and 1990 Vrancea seismic events

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Earthquake Engineering and Engineering Vibration 2014年第1期13卷 125-135页

作者： Florin Pavel radu Vacareanu Cristian Neagu Andrei Pricopie Department of Reinforced Concrete Structures Technical University of Civil Engineering BucharestRomania Department of Strength of Materials Bridges and TunnelsTechnical University of Civil Engineering BucharestRomania

The Vrancea subcrustal earthquakes of August 30,1986 and May 30,1990 are the two most recent seismic events that have occurred in Romania with moment magnitudes M W ≥ *** spectral analysis of the strong ground motions recorded in Bucharest reveals that despite small differences in magnitude between the 1986 and 1990 earthquakes,their frequency contents are very different,sometimes even *** main focus of this study is to conduct a comparative analysis of the response spectra in terms of the bi-normalized response spectra(BNRS) proposed by Xu and Xie(2004 and 2007) for strong ground motions recorded in Bucharest during these two seismic *** mean absolute acceleration and relative velocity response spectra for the two earthquakes are discussed and ***,the mean bi-normalized absolute acceleration and normalized relative velocity response spectra with respect to the control period T C are computed for the ground motions recorded in Bucharest in 1986 and *** predominant period T P is also used in this study for the normalization of the spectral period ***,the methodology proposed by Martinez-Perreira and Bommer(1998) is applied in order to estimate the seismic intensity of the two *** results are discussed and several conclusions regarding the possibility of using the bi-normalized response spectra(BNRS) are given.

关键词： response spectra bi-normalized response spectra dynamic amplifi cation factor control period damage potential parameters

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