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In situ magnesium calcium phosphate cements formation: From one pot powders precursors synthesis to in vitro investigations

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Bioactive materials 2020年第3期5卷 644-658页

作者： m.A.Goldberg P.A.Krohicheva A.s.Fomin D.R.Khairutdinova O.s.Antonova A.s.Baikin V.V.smirnov A.A.Fomina A.V.Leonov I.V.mikheev N.s.sergeeva s.A.Akhmedova s.m.Barinov V.s.Komlev A.A.Baikov Institute of metallurgy and materials science Russian Academy of Sciences119334Leninsky av49MoscowRussian Federation m.V.Lomonosov moscow state University Department of Chemistry119991Leninskie Gory1MoscowRussian Federation Federal state Budgetary Institution National medical Research Radiological Center of the ministry of health of the Russian Federation 1252842nd Botkinsky pass.3MoscowRussian Federation

Calcium phosphate cements are of great interest for researchers and their applications in medical practice ***,they have a number of drawbacks including the insufficient level of mechanical properties and low degradation ***(mgNh4PO4)-based cements,which grew in popularity in recent years,despite their neutral ph and acceptable mechanical performance,release undesirable Nh4+ions during their *** issue could be avoided by replacement of ammonia ions in the cement liquid with sodium,however,such cements have a ph values of 9–10,leading to ***,the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties:neutral ph,sufficient mechanical properties,and the absence of cytotoxicity,applying Na2hPO4-based cement *** this purpose,cement powders precursors in the CaO-mgO-P2O5 system were synthesized by one-pot process in a wide composition range,and their properties were *** optimal performance was observed for the cements with(Ca+mg)/P ratio of 1.67,which are characterized by newberyite phase formation during setting reaction,ph values close to 7,sufficient compressive strength up to 22±3 mPa(for 20 mol.%of mg),dense microstructure and adequate matrix properties of the *** set of features.make those materials promising candidates for medical applications.

关键词： magnesium calcium phosphate cement stanfieldite Whitlockite Newberyite Brushite In vitro investigations

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Idiosyncratic behaviour of(Na_(0.49)5K_(0.455)Li_(0.05))(Nb_(0.95)Ta_(0.05))O_3-la_2O_3 ceramics: synergistically improved thermal stability, ageing, and fatigue properties

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Journal of Advanced Ceramics 2019年第1期8卷 79-89页

作者： Bhupender RAWAL N. N. WAThORE B.PRAVEENKUmAR h. s. PANDA Armament Research and Development Establis.ment Department of materials Engineering Defence Institute of Advanced Technology

la_2 O_3 doped(Na0.495 K0.455 Li0.05)(Nb0.95 Ta0.05)O_3 ceramics are prepared using modified milling process, and the influences of la2 O3 on ferroelectric behaviour, ageing characteristics, thermal stability, electrical stability, crystal structure, microstructure, dielectric and piezoelectric properties were reported. la_2 O_3 addition improved the ferroelectric characteristic substantially, and obtained remnant polarization(Pr) and maximum strain(smax) around 34.3 C/cm^2 and 0.13% ***_2 O_3 doped ceramics improved the thermal stability and were stable up to 180 ℃ compared to undoped ceramics(120 ℃). The Rietveld refinement along with the high-temperature X-ray diffraction studies suggested the presence of monoclinic phase in la doped compositions, which is responsible for their idiosyncratic behaviour. The maximum values were obtained around 179 pC/N and 0.385 for piezoelectric constant(d33) and electromechanical coupling factor(kp) respectively in la_2 O_3 doped s.mples(0.02 wt%), which also exhibited the lowest ageing rate and stable electrical fatigue behaviour.

关键词： dielectric fatigue piezoelectric thermal stability

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Asses.ment of groundwater suitability for different activities in Toshka district,south Egypt

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Journal of Groundwater science and Engineering 2024年第1期12卷 34-48页

作者： marwa m Aly shymaa AK Fayad Ahmed mI Abd Elhamid Faculty of Engineering mataria Helwan UniversityCairo 11718Egypt Division of Engineering International Academy for Engineering and Media Science(IAEMS)6th of October City 15515Egypt hydraulics Research Institute National Water Research CenterMWRICairo 13621Egypt

Globally,groundwater has globally emerged as a crucial freshwater source for domestic,irrigation,and industrial *** evaluation of groundwater quality in the Toshka region is imperative to ensure its suitability for the extensive agricultural and industrial activities underway in this promising,groundwater-dependent development *** is particularly significant as Egypt increasingly relies on groundwater reserves to address freshwater deficits and to implement mega-development projects in barren *** this study,fifty-two s.mples were collected from the recently drilled wells tapping into the Nubian sandstone Aquifer(NsA)in the Toshka *** quality was assessed through hydrochemical analysis,Piper diagram,and various indicators such as Na%,sAR,RsC,KR,mh and *** hydrochemical analysis revealed improved groundwater quality characteristics,attributed to continuous recharge from lake *** Piper diagram categorised most of the water s.mples as"secondary salinity"water *** all wells proved suitable for irrigation with only two wells unsuitable based on mh values and six wells based on KR *** Total hardness(Th)values,all s.mples were classified as"soft",indicating their suitability for domestic and industrial *** Quality Index(WQI)results concluded that all s.mples.met WhO and FAO guidelines for drinking and irrigation,*** distribution maps,constructed using GIs,facilitate the interpretation of the *** monitoring of quality parameters is essential to detect any deviation from permissible limits.

关键词： Nubian sandstone Aquifer Water Quality Asses.ment hydro-chemical Analysis Irrigation Quality Indicators Domestic Use Water Quality Index

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Nonlinear static and dynamic responses of an electrically actuated viscoelastic microbeam

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Acta mechanica sinica 2009年第2期25卷 211-218页

作者： y.m.Fu J.Zhang College of mechanics and Aerospace Hunan University

On the basis of the Euler-Bernoulli hypothesis, nonlinear static and dynamic responses of a viscoelastic microbeam under two kinds of electric forces [a purely direct current （DC） and a combined current composed of a DC and an alternating current] are studied. By using Taylor series expansion, a governing equation of nonlinear integro-differential type is derived, and numerical analyses are performed. When a purely DC is applied, there exist an instantaneous pull-in voltage and a durable pull-in voltage of which the physical meanings are also given, whereas under an applied combined current, the effect of the element relaxation coefficient on the dynamic pull-in phenomenon is observed where the largest Lyapunov exponent is taken as a criterion for the dynamic pull-in instability of viscoelastic microbeams.

关键词： mEms Viscoelastic microbeam Nonlineardynamics

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Valorization of AZ91 by the hydrolysis reaction for hydrogen production(Electrochemical approach)

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Journal of magnesium and Alloys 2021年第6期9卷 1942-1953页

作者： s.Al Bacha I.Aubert m.Zakhour m.Nakhl J.L.Bobet LCPm/PR2N(EDsT) Lebanese UniversityFaculty of Science II90656 Jdeidet El MetnLebanon Universitéde Bordeaux ICMCBCNRSUMR 5026F-33600 PessacFrance University of Bordeaux CNRSArts et MétiersInstitute of technologyBordeaux INPINRAEI2M BordeauxF-33400 TalenceFrance

The hydrolysis of mg-based materials appears to be an ideal solution for clean energy *** hydrogen was produced by the hydrolysis reaction of a"standard"AZ91 alloy(called AZ91 in the following)in"model"seawater *** milling speeds(i.e.250 rpm and 350 rpm)were tested to enhance the reactivity of *** and AlCl_(3)were used as ball milling *** at higher rotational speed is.more energetic,hence it ameliorates the most the hydrolysis performance of *** both milling additives,AlCl_(3)enhances the most the hydrolysis of AZ91 with a generation of 65%of its theoretical h_(2)generation *** best material was obtained by milling AZ91 at 350 rpm with graphite for 2 h followed by a further milling with AlCl_(3)for 2h-a yield of 75%of its theoretical h_(2)generation capacity was reached within a few *** corrosion behavior of milled AZ91 was investigated by anodic polarization and electrochemical impedance spectroscopy(EIs).The calculated electrochemical parameters from EIs fitting of two materials.milled under different conditions but with the s.me milling additive are approximately the *** suggests that,in order to fully evaluate the reactivity of AZ91,hydrolysis,anodic polarization and EIs.must be considered.

关键词： Ball milling AZ91 mg_(17)Al_(12) Corrosion hydrogen Electrochemical impedance spectroscopy

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Cervical Cancer Prediction Empowered with Federated machine Learning

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Computers, materials & Continua 2024年第4期79卷 963-981页

作者： muhammad Umar Nasir Omar Kass.m Khalil Karamath Ateeq Bass.m saleemAllah Almogadwy m.A.Khan Khan muhammad Adnan Department of Computer sciences Bahria University Lahore CampusLahore54000Pakistan Faculty of Information Technology Liwa CollegeAbu Dhabi20009UAE Department of Computing Skyline University CollegeSharjah999041UAE Department of Computer science Taibah UniversityMedina42315Saudi Arabia Riphah school of Computing and Innovation Faculty of ComputingRiphah International UniversityLahore54000Pakistan Department of software Faculty of Artificial Intelligence and SoftwareGachon UniversitySeongnam13120Korea

Cervical cancer is an intrusive cancer that imitates various women around the world. Cervical cancer ranks in thefourth position because of the leading death cause in its premature stages. The cervix which is the lower end of thevagina that connects the uterus and vagina forms a cancerous tumor very slowly. This pre-mature cancerous tumorin the cervix is deadly if it cannot be detected in the early stages. so, in this delineated study, the proposed approachuses federated machine learning with numerous.machine learning solvers for the prediction of cervical cancer totrain the weights with varying neurons empowered fuzzed techniques to align the neurons, Internet of medicalThings (IomT) to fetch data and blockchain technology for data privacy and models protection from hazardousattacks. The proposed approach achieves the highest cervical cancer prediction accuracy of 99.26% and a 0.74%misprediction rate. so, the proposed approach shows the best prediction results of cervical cancer in its early stageswith the help of patient clinical records, and all medical professionals will get beneficial diagnosing approachesfrom this study and detect cervical cancer in its early stages which reduce the overall death ratio of women due tocervical cancer.

关键词： Cervical cancer federated machine learning neurons blockchain technology

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Experimental study of the Influence of Process Pressure and Gas Composition on GaAs Etching Characteristics in Cl_2/BCl_3-Based Inductively Coupled Plasma

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Plasma science and Technology 2011年第2期13卷 223-229页

作者： D.s.RAWAL B.K.sEhGAL R.mURALIDhARAN h.K.mALIK solid state Physics laboratory PWAPA laboratory Department of Physics Indian Institute of Technology Delhi

A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.

关键词： GaAs inductively coupled plasma etching ion energy etch yield

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hybridizing micro-Ti with nano-B_(4)C particulates to improve the microstructural and mechanical characteristics of mg-Ti composite

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Journal of magnesium and Alloys 2014年第1期2卷 13-19页

作者： s.sankaranarayanan s.Jayalaks.mi m.Gupta Department of mechanical Engineering National University of Singapore(NUS)9 Engineering Drive 1Singapore 117576Singapore

In this study,the effects of hybridizing micron-sized titanium particles with nano-sized boron carbide particles on the microstructural and mechanical properties of mg-Ti composite were *** characterization revealed grain refinement attributed to the presence of uniformly distributed micro-Ti particles embedded with nano-B_(4)C *** back scattered diffraction(EBsD)analyses of the mg-(Ti+B_(4)C)Bm hybrid composite showed relatively more localized recrystallized grains and lesser tensile twin fraction,when compared to *** evaluation of mechanical properties indicated that the best combination of strength and ductility was observed in the mg-(Ti+B_(4)C)Bm hybrid *** superior properties of the mg-(Ti+B_(4)C)Bm hybrid composite when compared to mg-Ti can be attributed to the presence of nano-reinforcement,the uniform distribution of the hybridized particles and the better interfacial bonding between the matrix and the reinforcement particles achieved by nano-B_(4)C addition.

关键词： Composite materials Electron microscopy(s.m) Electron diffraction(electron back scattered diffraction) mechanical properties

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size and shape effects on Curie temperature of ferromagnetic nanoparticles

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中国有色金属学会会刊：英文版 2007年第6期17卷 1451-1455页

作者：曹玲飞谢丹郭明星 h.s. Park T. Fujita school of Engineering University of Tokyo Bunkyo-ku Tokyo 113-8656 Japan laboratory of Crystallography Department of MaterialsETH-ZürichCH-8093 Zürich Switzerland school of materials science and Engineering Central South University

A s.mplified model was developed to describe the Curie temperature suppression of ferromagnetic nanoparticles. Based on a size and shape dependent model of cohesive energy, the critical temperature variations of ferromagnetic nanoparticles were deduced. It is predicted that the Curie temperature of nanoparticles depends on both size and shape conditions, among which the temperature suppression is strongly influenced by the particle size and the shape effect is comparably minor. The calculation values for freestanding nanoparticles are in good agreement with other theoretical model and the experimental results. The model is also potential for predictions for the nanoparticles embedded in different substrates.

关键词：纳米粒子铁磁体居里温度尺寸形状效应

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Effect of y^(3+), Gd^(3+) and la^(3+) dopant ions on structural, optical and electrical properties of o-mullite nanoparticles

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Journal of Rare Earths 2014年第1期32卷 37-42页

作者： m.m.s.sanad m.m.Rashad E.A.Abdel-Aal m.F.El-shahat K.Powers Central metallurgical R & D Institute Particle Engineering Research Center University of Florida Faculty of science Ain Shams University

Dielectric ceramics of m（x）Al6（1-x）si2O13 doped mullite were synthesized via co-precipitation technique. The X-ray diffrac-tion profiles revealed that these nanoparticles were crystallized well and the volume of mullite unit cell was increased as a function of the ionic radius of dopant ion. TEm images showed regular orthorhombic crystal morphology for the pure mullite s.mple. meanwhile, the doped s.mples exhibited slightly distorted crystal morphology of larger particle sizes. DsC thermograms evinced that the exo-thermic peak temperature of mullite was shifted to the lower value with m3＋ion insertion. The photoluminescence spectra were stud-ied for mullite s.mples, and it was found that the intensity of the emission spectra was affected by the m3＋ion type. It was found that, y3＋doped mullite achieved the minimum dielectric loss value of 0.01 in the radio wave frequency region （1 mhz）. meanwhile, Gd3＋doped mullite achieved the minimum dielectric loss value of 0.09 in the microwave frequency region （1 Ghz）.

关键词： rare earths doped mullite photoluminescence crystallization temperature dielectric ceramics

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