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Three-dimensional mixed convection stagnation-point fow past a vertical surface with second-order slip velocity

Applied Mathematics and Mechanics(English Edition) 2023年第4期44卷 641-652页

作者： A.V.ROSca N.c.ROSca i.POP Department of Statistics-Forecasts-Mathematics Faculty of Economics and Business AdministrationBabes-Bolyai UniversityCluj-Napoca 400084Romania Department of Mathematics Faculty of Mathematics and Computer ScienceBabes-Bolyai UniversityCluj-Napoca 400084Romania Academy of Romanian Scientists 3 Ilfov StreetBucharest 050044Romania

This study is concerned with the three-dimensional(3D)stagnation-point for the mixed convection flow past a vertical surface considering the first-order and secondorder velocity *** the authors’knowledge,this is the first study presenting this very interesting *** partial differential equations for the flow problem are transformed into nonlinear ordinary differential equations(ODEs)by using appropriate similarity *** ODEs with the corresponding boundary conditions are numerically solved by utilizing the bvp4c solver in MATLAB programming *** effects of the governing parameters on the non-dimensional velocity profiles,temperature profiles,skin friction coefficients,and the local Nusselt number are presented in detail through a series of graphs and ***,it is reported that the reduced skin friction coefficient decreases for the assisting flow situation and increases for the opposing flow *** numerical computations of the present work are compared with those from other research available in specific situations,and an excellent consensus is *** exciting feature for this work is the existence of dual *** important remark is that the dual solutions exist for both assisting and opposing flows.A linear stability analysis is performed showing that one solution is stable and the other solution is not *** notice that the mixed convection and velocity slip parameters have strong effects on the flow *** effects are depicted in graphs and discussed in this *** obtained results show that the first-order and second-order slip parameters have a considerable effect on the flow,as well as on the heat transfer characteristics.

关键词： three-dimensional(3D)mixed convection flow stagnation point flow first-order slip velocity second-order slip velocity numerical solution stability analysis

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Bofedal response to climate variability, local management, and water extraction: A case study of chucuyo, Northern chile

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Journal of Mountain Science 2022年第1期19卷 241-252页

作者： uribe-ÁLvaREZ Monserrat c PRiETO Manuel MESEGUER-RUiZ Oliver Departamento de ciencias históricas y Geográficas Universidad de TarapacáArica 1010069Chile Departamento de ciencias históricas y Geográficas Universidad de TarapacáIquique 1101783Chile

Andean high-altitude wetlands are important ecosystems that serve a range of socialecological functions. in the Andes, bofedales, a specific type of peat-producing wetland, are essential for the sustainability of mountain ecosystems and indigenous pastoralist communities. The chucuyo bofedal in northern chile is affected by climatic variability and water extraction for agricultural uses via the Lauca canal. herders in the local community also actively manage this wetland according to their traditional ecological knowledge to ensure permanent fodder for their animals. in this article, we analyze the annual behavior of the chucuyo bofedal after the wet season. Based on precipitation data, extracted water flows, vegetation vigor from satellite images, and an ethnographic approach, we determined that the bofedal’s productivity was negatively correlated with the amount of precipitation and positively correlated with the surface area of the wetland. however, water extraction via the Lauca channel had no significant relationship with either surface area or vegetation vigor. We identify community practices and traditional ecological knowledge as key elements in the maintenance of these ecosystems. This situation is critical in the context of an aging population and the current pattern of migration out of the region to urban areas. The results provide substantial empirical evidence for future decision-making regarding the conservation of these ecosystems.

关键词： Atacama Bofedales indigenous people Lauca canal Normalized Difference Vegetation index

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Status and prospects for symmetric organic redox flow batteries

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Journal of Energy chemistry 2025年第1期100卷 125-143页

作者： Md Al Raihan c.Adam Dyker Department of chemistry University of New Brunswick

As environmental concerns from fossil fuel consumption intensify, large-scale energy storage becomes imperative for the integration of renewable sources like wind, hydro, and solar with the electrical *** flow batteries, particularly those employing organic molecules, are positioned as a key technology for this purpose. This review explores the growing field of symmetric organic redox flow batteries(ORFBs) within this context. Unlike traditional asymmetric designs based on unique active materials for each electrode, symmetric ORFBs involve a single bipolar species for both electrodes. This review highlights the benefits of a symmetric design, and categorizes five distinct classes of organic bipolar molecules used in both aqueous and non-aqueous solvents. By providing a comprehensive overview of their cell cycling and performance characteristics, the strengths and weaknesses of the diverse categories of bipolar molecules are highlighted for both solvent systems, as are opportunities for future development. This should guide new research directions and advance the development of practical symmetric ORFBs.

关键词： Redox flow battery Symmetric battery Organic battery Aqueous electrolyte Non-aqueous electrolyte

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Roles of soil-structure interaction and damping in base-isolated structures built on numerous soil layers overlying a half-space

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 387-400页

作者： c.S.Tsai c.i.hsueh h.c.Su Department of civil Engineering Feng Chia University Graduate institute of civil & hydraulic Engineering Feng Chia University Department of Water Resources Engineering and conservation Feng Chia University

This study examines the roles of soil-structure interaction （SSi）, higher modes, and damping in a base-isolated structure built on multiple layers of soil overlying a half space. closed-form solutions for the entire system, including a superstructure, seismic isolator, and numerous soil layers overlying a half-space, were obtained. The formulations obtained in this study simply in terms of well-known frequencies and mechanical impedance ratios can explicitly interpret the dynamic behavior of a base-isolated structure interacting with multiple soil layers overlying a half-space. The key factors influencing the performance of the isolation system are the damping ratio of the isolator and the ratio of the natural frequency of the fixed-base structure to that of the isolated structure by assuming that the superstructure moves as a rigid body. This study reveals that higher damping in the base isolator is unfavorable to higher mode responses that usually dominate the responses of the superstructure and that the damping mechanism plays an important role in transmitting energy in addition to absorbing energy. it is also concluded that it is possible to design a soft soil layer as an isolation system for isolating vibration energy.

关键词： base isolation seismic isolation soil-structure interaction closed- form solution higher-mode effects soilstratum passive control damping effects

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Acquired sensorineural hearing loss,oxidative stress,and microRNAs

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Neural Regeneration Research 2025年第9期20卷 2513-2519页

作者： Desmond A.Nunez Ru c.Guo Division of Otolaryngology–head&Neck Surgery Department of SurgeryFaculty of MedicineThe University of British ColumbiaVancouverBCCanada Division of Otolaryngology–head&Neck Surgery Gordon&Leslie Diamond Health Care CentreVancouver General HospitalVancouverBCCanada Faculty of Medicine–The University of British columbia VancouverBCCanada

hearing loss is the third leading cause of human ***-related hearing loss,one type of acquired sensorineural hearing loss,is largely responsible for this escalating global health ***-induced,ototoxic,and idiopathic sudden sensorineural are other less common types of acquired hearing *** etiology of these conditions is complex and multi-fa ctorial involving an interplay of genetic and environmental *** stress has recently been proposed as a likely linking cause in most types of acquired sensorineural hearing *** non-coding RNA sequences known as microRNAs(miRNAs)have increasingly been shown to play a role in cellular hypoxia and oxidative stress responses including promoting an apoptotic *** hair cell death is a central histopathological finding in sensorineural hearing *** these cells do not regenerate in humans,it underlies the irreversibility of human age-related hearing *** EMBASE,Ovid MEDLiNE,Web of Science core collection,and *** databases over the period August 1,2018 to July 31,2023 were searched with"hearing loss,""hypoxamiRs,""hypoxia,""microRNAs,""ischemia,"and"oxidative stress"text words for English language primary study publications or registered clinical *** red clinical trials known to the senior author we re also assessed.A total of 222studies were thus *** excluding duplicates,editorials,retra ctions,secondary research studies,and non-English language articles,39 primary studies and clinical trials underwent full-text *** resulted in 11 animal,in vitro,and/or human subject journal articles and 8 registered clinical trial database entries which form the basis of this narrative *** miR-34a and miR-29b levels increase with age in *** miRNAs were demonstrated in human neuroblastoma and murine cochlear cell lines to target Sirtuin 1/peroxisome proliferato r-activated receptor gamma coactivator-1-alpha(SiRT1/P Gc-1α),SiRT

关键词： hearing loss hypoxia microRNAs oxidative stress sensorineural

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A-site ordered state in manganites with perovskite-like structure based on optimally doped compounds Ln0.70Ba0.30MnO3（Ln=Pr,Nd）

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Journal of Rare Earths 2019年第11期37卷 1242-1249页

作者： S.V.Trukhanov va Khomchenko D.V.Karpinsky M.V.Silibin A.V.Trukhanov L.S.Lobanovsky h.Szymczak c.E.Botez i.O.Troyanchuk National University of Science and Technology MiSiS 119049 MoscowLeninsky Av.4Russia South Ural State University 454080 ChelyabinskLenin Av.76Russia Scientific-Practical Materials Research centre of NASB 220072 MinskBelarus cFisUc Department of PhysicsUniversity of Coimbra3004-516 CoimbraPortugal National Research University of Electronic Technology"MiET 124498 ZelenogradMoscowRussia institute for Bionic Technologies and Engineering I.M.Sechenov First Moscow State Medical University2-4 Bolshaya Pirogovskaya St.119991 MoscowRussia institute of Physics Polish Academy of Sciences02-668 WarsawPoland The University of Texas at El Paso El PasoTX 79968-0515USA

in this paper,we report on the crystal structure and magnetic properties of the nano structured Baordered phases of rare-earth manganites obtained from the optimally doped solid solutions Ln0.70Ba0.30MnO3(Ln=Pr,Nd).The materials were studied by X-ray diffraction,scanning electron microscopy,energy dispersive spectroscopy and SQUiD-magnetometry *** is found that states with different degrees of cation ordering in the A-sublattice of the ABO3 perovskite can be obtained by employing special conditions of chemical *** particular,reduction of the parent compounds results in the formation of a nanocomposite containing ferrimagnetic anion-deficient ordered phase *** of the composite does not change an average size of the nanocrystallites,but drastically alters their phase composition to stabilize ferromagnetic stoichiometric ordered phase LnBaMn2O6 and ferromagnetic superstoichiometric disordered phase Ln0.90Ba0.10MnO3+δ.it is shown that the magnetic properties of the materials are determined by the joint action of chemical(cation ordering)and external(surface tension)pressures.

关键词： ionic order Magnetic transition Perovskite Manganite Rare earths

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Passive Q-switching in an erbium-doped fiber laser using tungsten sulphoselenide as a saturable absorber

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chinese Optics Letters 2018年第2期16卷 69-73页

作者： h.Ahmad Z.c.Tiu S.i.Ooi Photonics Research centre University of Malaya

A highly stable Q-switched laser incorporating a mechanically exfoliated tungsten sulphoselenide （WSSe） thin sheet saturable absorber （SA） is proposed and demonstrated. The SA assembly, formed by sandwiching a thin WSSe sheet between two fiber ferrules within the erbium-doped fiber laser, is used to effectively modulate the laser cavity losses. The WSSe-based SA has a saturation intensity of ~0.006 MW∕cm^2 and a modulation depth of 7.8%, giving an optimum Q-switched laser output with a maximum repetition rate of 61.81 khz and a minimum pulse width of 2.6 μs. The laser＇s highest output power of 0.45 mW and highest pulse energy of 7.31 nJ are achieved at the maximum pump power of 280.5 mW. The tunability of the cavity＇s output at the maximum pump power is analyzed with a c-band tunable bandpass filter, giving a broad tunable range of ~40 nm, from 1530 nm to 1570 nm. The output performance of the tunable Q-switched laser correlates well with the gain spectrum of erbium-doped fibers, with the shift in the gain profile as a result of the saturated SA.

关键词： Passive Q-switching in an erbium-doped fiber laser using tungsten sulphoselenide as a saturable absorber SA EDF

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Microstructure and creep properties of Mg-4Al-2Sn-1(ca,Sr) alloys

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Transactions of Nonferrous Metals Society of china 2010年第7期20卷 1184-1191页

作者： B.h.KiM K.c.PARK Y.h.PARK i.M.PARK Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The effects of ca and Sr addition on the microstructure and creep properties of Mg-4Al-2Sn alloys were examined. Tensile tests at 25 ℃ and 200 ℃ and creep tests at 150 ℃ and 200 ℃ were carried out to estimate the room temperature and high temperature mechanical properties of these alloys. The microstrueture of the Mg-4Al-2Sn alloy showed dendritic a-Mg, Mg17Al12 and Mg2Sn phases. The latter two phases precipitated along the grain boundaries. The addition of ca and Sr resulted in the formation of ternary caMgSn and SrMgSn phases within the grain. The grain size was reduced slightly with the addition of Sr and ca. The tensile strength was decreased by the addition of ca and Sr at room temperature. however, the high temperature tensile strength was increased. The creep strength was improved by the addition of ca and Sr.

关键词： magnesium alloys ca Sr void initiation mechanical properties creep mechanism

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Effect of retained austenite and nonmetallic inclusions on the thermal/electrical properties and resistance spot welding nuggets of Si-containing TRiP steels

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international Journal of Minerals,Metallurgy and Materials 2019年第1期26卷 52-63页

作者： V.h.vargas i.Mejía V.h.Baltazar-hernández c.Maldonado Metallurgy and Materials Research institute Universidad Michoacana de San Nicolás de Hidalgo Edificio "U" Ciudad Universitaria Materials Science and Engineering Program Autonomous University of Zacatecas

Five advanced high-strength transformation-induced plasticity(TRiP) steels with different chemical compositions were studied to correlate the retained austenite and nonmetallic inclusion content with their physical properties and the characteristics of the resistance spot welding nuggets. Electrical and thermal properties and equilibrium phases of TRiP steels were predicted using the JMatPro? software. Retained austenite and nonmetallic inclusions were quantified by X-ray diffraction and saturation magnetization techniques. The nonmetallic inclusions were characterized by scanning electron microscopy. The results show that the contents of Si, c, Al, and Mn in TRiP steels increase both the retained austenite and the nonmetallic inclusion contents. We found that nonmetallic inclusions affect the thermal and electrical properties of the TRiP steels and that the differences between these properties tend to result in different cooling rates during the welding process. The results are discussed in terms of the electrical and thermal properties determined from the chemical composition and their impact on the resistance spot welding nuggets.

关键词： transformation-induced plasticity steel retained austenite non-metallic inclusions magnetic saturation electrical properties thermal properties resistance spot welding nugget

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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： carina hromada Patrick heimel Markus Kerbl LászlóGál Sylvia Nürnberger Barbara Schaedl James Ferguson Nicole Swiadek Xavier Monforte Johannes c.heinzel Antal Nógrádi Andreas h.Teuschl-Woller David hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian cluster for Tissue Regeneration ViennaAustria Ludwig Boltzmann institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGcs). however, the use of tNGcs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGc would help eliminate necrotic processes and lead to improved regeneration. in this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGcs and compared the various features of these improved silk^(+) tNGcs with the tubes without holes(silk^(–) tNGcs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tNGcs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGcs at 7 weeks postoperatively. in the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGcs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGcs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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