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Comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable Mg-3Y alloy prepared by selective laser melting and spark plasma sintering

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Journal of Magnesium and Alloys 2024年第4期12卷 1496-1510页

作者： P.Minárik M.Zemková S.Šašek J.Dittrich M.knapek F.lukáˇc D.koutný J.Jaroš r.král Faculty of Mathematics and Physics Charles UniversityKe Karlovu 5Praha 12116Czech Republic research Centre University ofŽilinaUniverzitná8215/1Žilina 01026Slovakia Institute of Plasma Physics of the Czech Academy of Sciences Za Slovankou 1782/318200 Praha 8Czech Republic Institute of Machine and Industrial Design Brno University of TechnologyTechnická2896/2Brno 61669Czech Republic

This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SlM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SlM material and unmeasurably low porosity in the SPS *** main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion *** materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SlM and SPS materials,*** corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SlM one and comparable to the conventional extruded *** digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SlM *** the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

关键词： Magnesium Yttrium Powder metallurgy Microstructure Mechanical strength Corrosion resistance

Sc元素添加对双辊铸轧Al−Cu−li−Mg−Zr基合金热处理的影响

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Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1759-1773页

作者： rostislav krÁlÍk Barbora kŘIVSkÁ lucia BAJTOŠOVÁ Mykhailo STOlBCHENkO Mirko SCHAPEr Olexandr GrYDIN Miroslav CIESlAr Department of Physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116PragueCzech Republic Department of Materials Science Faculty of Mechanical EngineeringUniversity of PaderbornWarburger Straße 10033098PaderbornGermany

提出制备含Sc的Al−Cu−li−Mg−Zr基合金带材的工艺方案。即先采用双辊铸轧技术制备近净形状的3 mm厚带材,再对其进行均匀化/固溶处理。研究两种Al−Cu−li−Mg−Zr基双辊铸轧合金,其中一种添加质量分数为0.17%的Sc,另一种未添加Sc。两种合金... 详细信息

提出制备含Sc的Al−Cu−li−Mg−Zr基合金带材的工艺方案。即先采用双辊铸轧技术制备近净形状的3 mm厚带材,再对其进行均匀化/固溶处理。研究两种Al−Cu−li−Mg−Zr基双辊铸轧合金,其中一种添加质量分数为0.17%的Sc,另一种未添加Sc。两种合金均先在300℃下退火30 min,然后在450℃下退火30 min以及530℃下退火30 min,随后进行室温水淬。前两段退火后组织中生成了细小、弥散的Al_(3)Zr/Al_(3)(Sc,Zr)颗粒。最后的退火步骤起到了均匀化/固溶处理的作用。双辊铸轧材料的细小晶粒结构使含有主要合金元素的原始颗粒在较短的退火时间内溶解。缩短保温时间可以限制表面层中li的耗尽和Al_(3)Zr/Al_(3)(Sc,Zr)弥散相的明显粗化。铸态含Sc材料已经具有明显细小的晶粒结构,而经均匀化/固溶处理后生成的Al_(3)(Sc,Zr)弥散相抑制了晶粒在高温下发生粗化。在后续180℃下时效处理后,形成了θʹ(Al_(2)Cu)、T1(Al_(2)Culi)和S'(Al_(2)CuMg)强化相。在峰值时效状态下,屈服强度提高了200 MPa,这一数值与类似直接冷却铸造材料的相当,从而证实了所提方案的合理性。

关键词：显微组织力学性能 Al−Cu−li基合金 Sc合金化双辊铸轧

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Classification of Conversational Sentences Using an Ensemble Pre-Trained language Model with the Fine-Tuned Parameter

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Computers, Materials & Continua 2024年第2期78卷 1669-1686页

作者： r.Sujatha k.Nimala Department of Networking and Communications SRM Institute of Science and TechnologyKattankulathurChengalpattuTamilnadu603203India

Sentence classification is the process of categorizing a sentence based on the context of the *** categorization requires more semantic highlights than other tasks,such as dependence parsing,which requires more syntactic *** existing strategies focus on the general semantics of a conversation without involving the context of the sentence,recognizing the progress and comparing *** ensemble pre-trained language model was taken up here to classify the conversation sentences from the conversation *** conversational sentences are classified into four categories:information,question,directive,and *** classification label sequences are for analyzing the conversation progress and predicting the pecking order of the *** of Bidirectional Encoder for representation of Transformer(BErT),robustly Optimized BErT pretraining Approach(roBErTa),Generative Pre-Trained Transformer(GPT),DistilBErT and Generalized Autoregressive Pretraining for language Understanding(XlNet)models are trained on conversation corpus with *** tuning approach is carried out for better performance on sentence *** Ensemble of Pre-trained language Models with a Hyperparameter Tuning(EPlM-HT)system is trained on an annotated conversation *** proposed approach outperformed compared to the base BErT,GPT,DistilBErT and XlNet transformer *** proposed ensemble model with the fine-tuned parameters achieved an F1_score of 0.88.

关键词： Bidirectional encoder for representation of transformer conversation ensemble model fine-tuning generalized autoregressive pretraining for language understanding generative pre-trained transformer hyperparameter tuning natural language processing robustly optimized BErT pretraining approach sentence classification transformer models

Cool white light and tunable multicolor emission from Tb^(3+)/Dy^(3+)co-activated glasses under different excitations for WlEDs

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Journal of rare Earths 2024年第1期42卷 46-56,I0002页

作者： l.Vijayalakshmi k.Naveen kumar Jong Dae Baek Department of Automotive Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea Department of Mechanical Engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(lZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)Pl spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):lZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated lZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting lEDs

Covalent Bond Based Android Malware Detection Using Permission and System Call Pairs

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Computers, Materials & Continua 2024年第3期78卷 4283-4301页

作者： rahul Gupta kapil Sharma r.k.Garg Department of Information Technology Delhi Technological UniversityNew Delhi110042India Department of Mechanical Engineering Deenbandhu Chhotu Ram University of Science and TechnologyMurthal131039India

The prevalence of smartphones is deeply embedded in modern society,impacting various aspects of our *** versatility and functionalities have fundamentally changed how we communicate,work,seek entertainment,and access *** the many smartphones available,those operating on the Android platform dominate,being the most widely used *** widespread adoption of the Android OS has significantly contributed to increased malware attacks targeting the Android ecosystem in recent ***,there is an urgent need to develop new methods for detecting Android *** literature contains numerous works related to Android malware *** far as our understanding extends,we are the first ones to identify dangerous combinations of permissions and system calls to uncover malicious behavior in Android *** introduce a novel methodology that pairs permissions and system calls to distinguish between benign and malicious *** approach combines the advantages of static and dynamic analysis,offering a more comprehensive understanding of an application’s *** establish covalent bonds between permissions and system calls to assess their combined *** introduce a novel technique to determine these pairs’Covalent Bond Strength *** pair is assigned two scores,one for malicious behavior and another for benign *** scores serve as the basis for classifying applications as benign or *** correlating permissions with system calls,the study enables a detailed examination of how an app utilizes its requested permissions,aiding in differentiating legitimate and potentially harmful *** comprehensive analysis provides a robust framework for Android malware detection,marking a significant contribution to the *** results of our experiments demonstrate a remarkable overall accuracy of 97.5%,surpassing various state-of-the-art detection techniques proposed in the current literature.

关键词： Android malware android security hybrid analysis permission and system call pairs

14.1 W continuous-wave dual-end diode-pumped Er:lu_(2)O_(3)laser at 2.85μm

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Chinese Optics letters 2024年第1期22卷 84-89页

作者：梁洋洋李涛张百涛何京良 Sascha kalusniak 赵显 Christian kränkel key laboratory of laser&Infrared System Ministry of EducationShandong UniversityQingdao 266237China School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and ApplicationShandong UniversityQingdao 266237China Institute of Novel Semiconductors State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China leibniz-Institut für.kristallzüchtung(IkZ) Berlin 12489Germany

We present our efforts towards power scaling of Er:lu_(2)O_(3)lasers at 2.85μ*** applying a dual-end diode-pumped resonator scheme,we achieve an output power of 14.1 W at an absorbed pump power of 59.7 W with a slope efficiency of 26%.In a single-end pumped resonator scheme,an output power of 10.1 W is reached under 41.9 W of absorbed pump *** the best of our knowledge,this is the first single crystalline mid-infrared rare-earth-based solid-state laser with an output power exceeding 10 W at room temperature.

关键词： high-power continuous-wave laser mid-infrared laser dual-end pump scheme

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： l.I.kUZMINA Y.V.OSIPOV A.r.PESTErEV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front

Excellent photoluminescence and electrochemical properties of Sm^(3+) doped Ca_(2)MgSi_(2)O_(7) nanophosphor:Display and electrochemical sensor applications

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Journal of rare Earths 2024年第6期42卷 1046-1055,I0002页

作者： r.B.Basavaraj k.Sureshkumar D.P.Aarti M.B.Madhusudana reddy G.Nagaraju T.ramakrishnappa G.r.Navyashree k.r.Venkatesha Babu k.S.Hemalatha Department of Physics BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry School of Applied SciencesREVA UniversityBangalore560064India Energy Materials researchlaboratory Department of ChemistrySiddaganga Institute of TechnologyTumakuru57203KarnatakaIndia School of Physical Sciences REVA UniversityBangalore560057Indi Department of Physics Govt.Science CollegeBengaluru560001India Department of Physics Maharani Science College for WomenMaharani Cluster UniversityBengaluru560001India

A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as *** phase purity of the samples were confirmed by the powder X-ray diffraction(PXrD)*** single-phase tetragonal structure is observed from the PXrD results with no additional impurity *** band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DrS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the ***-like structures are observed from the SEM *** particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 *** interplanar distance is found to be 0.53 *** properties were systematically studied in *** phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic *** emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),*** the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current *** photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping *** dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching *** color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in *** optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange *** average CCT value obtained is 3362 *** average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to

关键词： Green combustion Photoluminescence Orange-red emission Color purity Sensors rare earths

Use of donepezil for neurocognitive recovery after brain injury in adult and pediatric populations:a scoping review

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Neural regeneration research 2024年第8期19卷 1686-1695页

作者： Avery l.Miller Nathan k.Evanson J.Michael Taylor University of Cincinnati College of Medicine CincinnatiOHUSA Department of Pediatrics University of CincinnatiCincinnatiOHUSA Department of Neurology and rehabilitation Medicine University of CincinnatiCincinnatiOHUSA Division of Pediatric rehabilitation Medicine Cincinnati Children’s Hospital Medical CenterCincinnatiOHUSA Division of Neurology Cincinnati Children’s Hospital Medical CenterCincinnatiOHUSA

There are few pharmacologic options for the treatment of cognitive deficits associated with traumatic brain injury in pediatric *** inhibitors such as donepezil have been evaluated in adult patients after traumatic brain injury,but relatively less is known about the effect in pediatric *** goal of this review is to identify knowledge gaps in the efficacy and safety of acetylcholinesterase inhibito rs as a potential a djuvant treatment fo r neurocognitive decline in pediatric patients with traumatic brain *** queried PubMed to identify literature published from database inception thro ugh June 2023 desc ribing the use of donepezil in young adult traumatic brain injury and pediatric patients with predefined *** on preselected search criteria,340 unique papers we re selected for title and abstra ct ***-two reco rds were reviewed in full after eliminating preclinical studies and pape rs outside the scope of the *** adult traumatic brain injury,we review results from 14 papers detailing 227 subjects where evidence suggests donepezil is well tole rated and shows both objective and patient-reported efficacy for reducing cognitive *** children,3 pape rs report on 5 children recovering from traumatic brain injury,showing limited *** additional 15 pediatric studies conducted in populations at risk for cognitive dysfunction provide a broader look at safety and efficacy in 210 patients in the pediatric age *** its promise for efficacy in adults with traumatic brain injury and tole rability in pediatric patients,we believe further study of donepezil for children and adolescents with traumatic brain injury is warranted.

关键词： acetylcholinesterase inhibitor adult cognition donepezil pediatrics traumatic brain injury