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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol M.N.Saridede S.S.Kaplan M.S.Sonmez department of Metallurgical and materials Engineering Yildiz Technical UniversityIstanbulTurkey department of Chemical Engineering and materials Science Stevens Institute of TechnologyNew JereyUSA department of Metallurgical and materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 *** energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： Gürel Cam Ali Günen Iskenderun technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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Correlation of work function and stacking fault energy through Kelvin probe force microscopy and nanohardness in diluteα-magnesium

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Journal of Magnesium and Alloys 2024年第1期12卷 237-250页

作者： Yigit Türe Ali Arslan Kaya Hüseyin Aydin Jiang Peng Servet Turan Eskisehir technical University Porsuk Vocational SchoolElectronics and Automation DepartmentProgram of MechatronicsEskisehirTurkey Mugla Sitki Kocman University Engineering FacultyMetallurgy and Materials Engineering DepartmentMuglaTurkey Hüseying Aydın TUBITAK MRCTurkey Jiang Peng Chongqing UniversityChina Eskisehir technical University Engineering FacultyMaterials Science and Engineering DepartmentEskisehirTurkey

Electronic interactions of the Group 2A elements with magnesium have been studied through the dilute solid solutions in binary Mg-Ca,Mg-Sr and Mg-Ba *** investigation incorporated the difference in the‘Work Function'(ΔWF)measured via Kelvin Probe Force Microscopy(KPFM),as a property directly affected by interatomic bond types,*** electronic structure,nanoindentation measurements,and Stacking Fault Energy values reported in the *** was shown that the nano-hardness of the solid-solutionα-Mg phase changed in the order of Mg-Ca>Mg-Sr>***,it was shown,by also considering the nano-hardness levels,that SFE of a solid-solution is closely correlated with its‘Work Function'***-hardness measurements on the eutectics andΔWF difference between eutectic phases enabled an assessment of the relative bond strength and the pertinent electronic structures of the eutectics in the three *** withΔWF and at least qualitative verification of those computed SFE values with some experimental measurement techniques were considered important as those computational methods are based on zero Kelvin degree,relatively simple atomic models and a number of *** asserted by this investigation,if the results of measurement techniques can be qualitatively correlated with those of the computational methods,it can be possible to evaluate the electronic structures in alloys,starting from binary systems,going to ternary and then multi-elemental *** investigation has shown that such a qualitative correlation is *** all,the SFE values are not treated as absolute values but rather become essential in comparative investigations when assessing the influences of alloying elements at a fundamental level,that is,free electron density *** study indicated that the principles of‘electronic metallurgy'in developing multi-elemental alloy systems can be followed via practical experimental methods,i.e.ΔWF measurements using KPF

关键词： Mg alloys Dilute alloys Work function Stacking fault energy Kelvin probe force microscopy Short range order Miedema Nanoindentation Eutectics

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Prospects and challenges in electrochemical nitrogen activation for ammonia synthesis

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Science China Chemistry 2024年第11期67卷 3510-3514页

作者： Xianbiao Fu Ib Chorkendorff department of Physics Technical University of Denmark

“The fixation of atmospheric nitrogen stands as one of the profound discoveries awaiting the ingenuity of chemists,”proclaimed William Crookes in his 1898 speech [1]. This statement swiftly surged like a colossal wa... 详细信息

关键词： REDUCTION EFFICIENCY N-2

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Gust response of an elasto-flexible morphing wing using fluid–structure interaction simulations

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Chinese Journal of Aeronautics 2024年第2期37卷 45-57页

作者： Jonathan PFLÜGER Christian BREITSAMTER department of Mechanical Engineering Technical University of MunichGarching 85748Germany

Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of *** often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight *** investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting *** focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type *** a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction ***,the numerical results are validated by experimental data from force and moment,flow field,and deformation ***,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic *** all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical *** the decay of the gust,they differ more the higher the aspect ratio of the *** considering the flow field,the main differences are due to the separation behavior on the upper side of the *** flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the *** at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.

关键词： Membrane wing Morphing wing Flexible wing surface Computational fluid dynam-ics Fluid-structure interaction Unsteady inflow condition Gust response

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Investigation of micro-scale shear response of sand–rubber granule mixture in terms of particle shape and grain scale deformability effects

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Particuology 2024年第7期90卷 452-469页

作者： Abdulmuttalip Ari Suat Akbulut department of Civil Engineering Yildiz Technical UniversityIstanbul34220Turkey

In this study,the effects of particle shape of rigid sand and soft rubber materials on macro-scale shear response were reasoned based on micro-scale *** this purpose,first,the shape properties of three different sand and two different rubber samples were quantified using image processing techniques,and the contact model parameters were calibrated through physical *** direct shear test was simulated in a two-dimensional discrete element software with realistic particle *** soft nature of rubber particles was reflected using body-centered cubic packing with a linear-parallel bond contact *** a result,coordination number,distribution of contact forces(i.e.,strong contact,and fabric anisotropy),and contact sliding were derived by the numerical *** has been observed that the particle shape leads to distinctive micro-scale responses due to the variations in the stiffness of the contacts.

关键词： Particle shape Sand Rubber Shear response Micro-scale response Discrete element method

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Acceptor-planarized typeⅠphotosensitizer for lipid droplet-targeted two-photon photodynamic therapy by ferroptosis

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Science China Chemistry 2024年第7期67卷 2392-2402页

作者： Jie Sha Weimin Liu Jiasheng Wu Yanping Wang Xuewei Li Haohui Ren Zhi Pang Wenjun Zhang Chun-Sing Lee Pengfei Wang Key Laboratory of Photochemical Conversion and Optoelectronic materials CityU-CAS Joint Laboratory of Functional Materials and DevicesTechnical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China Center of Super-Diamond and Advanced Films&department of materials Science and Engineering City University of Hong KongHong KongChina

Two-photon photodynamic therapy(TP-PDT)has garnered significant attention because of its excellent depth of tissue penetration and high spatiotemporal ***,the limited targeting ability and oxygen dependency of photosensitizers(PSs)significantly hinder the effectiveness of photodynamic therapy in hypoxic tumor ***,we designed and synthesized two lipid droplet(LD)-targeted two-photon PSs(TBPCP and TBCP)by reducing benzene rings to achieve“acceptor planarization”.Notably,acceptor planarization not only enhanced the intramolecular charge transfer but also transferred the photochemical reaction from typeⅡ(TBPCP)to typeⅠ(TBCP).Under the irradiation of 940 nm femtosecond pulsed laser,TBPCP and TBCP showed bright two-photon-excited fluorescence and excellent LD targeting in living *** TBPCP(typeⅡPS),the outstanding TP-PDT efficacy of TBCP(typeⅠPS)under hypoxic conditions could be obtained in both cellular experiments and multicellular tumor spheroids(MCTS)***,both TBPCP and TBCP could induce the lipid peroxidation in the typeⅠor typeⅡPDT due to the location of LD,depleting GSH and inactivating GPX4 to induce nonprogrammed ferroptosis in cells.

关键词： two-photon photodynamic therapy lipid droplet targeting acceptor planarization hypoxia tumor ferroptosis

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Theoretical and experimental studies of gas preparation system for pressurization and reactive control system of launch vehicle

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Chinese Journal of Aeronautics 2024年第7期37卷 168-177页

作者： Valeriy TRUSHLYAKOV Vladislav URBANSKY Vadim YUDINTSEV department of Aviation and Rocket Building Omsk State Technical UniversityOmsk 644050Russia

A new gas preparation system(GasPS-RCS)is proposed to solve two tasks:(A)to heat helium gas for tank pressurization;(B)to prepare gas for the Launch Vehicle(LV)Reactive Control System(RCS)at the LV orientation and stabilization sections of the LV on passive parts of the flight trajectory,to provide conditions for launching the Liquid Rocket Engine(LRE).The system includes a gas generator based on hydrogen peroxide,a separator for water separation,heat exchangers independent of the LRE,and gas-jet *** proposed new system allowed to reduce the length of pressurizing gas lines and reduce the increased helium gas consumption during the heat exchanger warm-up interval of the LRE during its launch.A special advantage of the proposed system is the possibility of ground testing of heat exchangers without an operating LRE.A mathematical model based on the first law of thermodynamics was used to perform a comparative analysis of GasPS-RCS with traditional pressurization and RCS *** validate the mathematical model,the experimental studies of helium pressurizing of a liquid nitrogen tank were *** results show that the deviation of experimental and calculated values for pressure is 1.1%and for temperature up to 2%.According to the results of comparative analysis,the GasPS-RCS is 259 kg lighter for the first stage and 80 kg lighter for the second stage of the LV.

关键词： Engine restart Reactive control system Tank pressurization Cryogenics Hydrogen peroxide Heat exchanger

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A robust optimization method for label noisy datasets based on adaptive threshold: Adaptive-k

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Frontiers of Computer Science 2024年第4期18卷 49-60页

作者： Enes DEDEOGLU Himmet Toprak KESGIN Mehmet Fatih AMASYALI department of Computer Engineering Yildiz Technical UniversityIstanbul 34220Turkey

The use of all samples in the optimization process does not produce robust results in datasets with label *** the gradients calculated according to the losses of the noisy samples cause the optimization process to go in the wrong *** this paper,we recommend using samples with loss less than a threshold determined during the optimization,instead of using all samples in the *** proposed method,Adaptive-k,aims to exclude label noise samples from the optimization process and make the process *** noisy datasets,we found that using a threshold-based approach,such as Adaptive-k,produces better results than using all samples or a fixed number of low-loss samples in the *** the basis of our theoretical analysis and experimental results,we show that the Adaptive-k method is closest to the performance of the Oracle,in which noisy samples are entirely removed from the ***-k is a simple but effective *** does not require prior knowledge of the noise ratio of the dataset,does not require additional model training,and does not increase training time *** the experiments,we also show that Adaptive-k is compatible with different optimizers such as SGD,SGDM,and *** code for Adaptive-k is available at GitHub.

关键词： robust optimization label noise noisy label deep learning noisy datasets noise ratio estimation robust training

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Electroactivity of the magnetotactic bacteria Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 103-110页

作者： Mathias Fessler Qingxian Su Marlene Mark Jensen Yifeng Zhang department of Environmental and Resource Engineering Technical University of DenmarkCopenhagenDK-2800Denmark

Magnetotactic bacteria reside in sediments and stratified water *** are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field ***,we show that two magnetotactic species,Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1,are *** *** and *** were able to generate current in microbial fuel cells with maximum power densities of 27 and 11μW/m^(2),*** the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite(Fe_(2)O_(3)).In addition,*** could reduce poorly crystalline iron oxide(FeOOH).Our study adds *** and *** to the growing list of known electroactive bacteria,and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

关键词： Magnetotactic bacteria Magnetospirillum magneticum Magnetospirillum gryphiswaldense Extracellular electron transfer Microbial fuel cells

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