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Supertetragonal BaZrS: A promising perovskite sulphide with giant ferroelectricity and low band gap

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Science China(Physics,Mechanics & Astronomy) 2024年

作者： Menglu Li sa Zhang Chenhan Liu Xiaotao Zu Liang Qiao Haiyan Xiao School of Physics University of Electronic Science and Technology of China College of Mathematics and Physics Chengdu University of Technology Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory Ministry of Education Key Laboratory of Numerical Simulation of Large-Scale Complex Systems School of Energy and Mechanical Engineering Nanjing Normal University

Over the past century, ferroelectricity has offered exciting opportunities for fundamental research and device ***, most of the discovered excellent ferroelectrics are oxide materials with large band gaps, limiting their potential for optoelectronics applications. Here using first-principles calculations we identify a new narrow-gap ferroelectric beyond oxides,i.e., ferroelectric perovskite sulphide BaZrS3. under large compressive strains, BaZrS3can be stabilized into a unique supertetragonal phase with an extraordinary polarization of 67.16 μC/cm2, which is even stronger than that of conventional oxide ferroelectrics. Excitingly, the supertetragonal BaZrS3exhibits a direct narrow band gap of 1.2 eV and excellent electronic properties. Based on the chemical bonding analysis, we attribute the formation of supertetragonal phase to charge re-ordering in which the π bond overlap along the long ?Zr-S? bond completely vanishes and the antibonding states of the σ bond appear below the Fermi level. Our work provides a conceptual strategy for designing new ferroelectrics for electronic and photovoltaic applications.

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The first record of dermochelyid turtles in the Eocene of Tierra del Fuego:new insights on the evolution of the Weddellian faunas

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Advances in Polar Science 2024年第1期35卷 63-77页

作者： Paula BONA Juliana STERLI Marcelo saúl de la FuENTE Eduardo OLIVERO Marta S.FERNÁNDEZ Marcelo REGuERO División Paleontología Vertebrados Museo de La Plata-Anexo IIFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La PlataLa Plata B1900FWAArgentina Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Ciudad Autónoma de Buenos Aires C1425FQBArgentina Museo Paleontológico Egidio Feruglio Trelew U9100Argentina Instituto de Evolución Ecología Histórica y Ambiente-CONICETSan Rafael CP5600Argentina Centro Austral de Investigaciones Científicas-CONICET Universidad Nacional de Tierra del FuegoUshuaia CP 9410Argentina División Paleontología Vertebrados Museo de La PlataUniversidad Nacional de La PlataLa Plata B1900FWAArgentina

The Antarctic Paleogene marine fossil record has been the key to reconstructing the evolution of the Weddellian Sea and final dismemberment of Southern *** this context,Eocene marine vertebrates from Seymour(Marambio)Island have provided valuable *** present the first Eocene record of marine reptiles from the southern Atlantic Coast of South *** corresponds to several postcranial turtle remains represented by a proximal end of the right humerus,three caudal and one thoracic vertebrae,a fragment of the left pubis,and ten ossicles of the dorsal carapace,coming from the Leticia Formation(late-mid Eocene)at Cabo Tiburones,Tierra del Fuego,*** materials show severalfeatures such as the size and general morphology of the humerus and vertebrae,and the presence of relatively small,irregular,smooth,and unkeeled ossicles,which allow us to assign them to Dermochelyidae *** are a cosmopolitan group ofcryptodiran turtles,registered from the late Cretaceous up to the recent,with some physiological-biological peculiarities(e.g.,endothermy and an exclusive jellyfish-based diet)and characterized by the presence of an osseous carapace formed by *** new finding from the Leticia Formation is an addition to the scarce and extremely fragmentary record of Eocene dermochelyids from the southern seas like those from the La Meseta and Submeseta formations(Antarctica)and the Waihao and Burnside formations(New Zealand).This new information allows us to discuss the presence of these turtles in such high latitudes in the past and its implication in the evolution of the Weddellian fauna.

关键词： marine reptiles sea turtles Dermochelyidae Paleogene La Meseta Formation Submeseta Formation Leticia Formation

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Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese Physics B 2024年第2期33卷 108-114页

作者： u.S.Mahabaleshwar G.P.Vanitha L.M.Pérez Emad H.Aly I.Pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching ***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

Model based odia numeral recognition using fuzzy aggregated features

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Frontiers of Computer Science 2014年第6期8卷 916-922页

作者： Tusar Kanti MISHRA Banshidhar MAJHI Pankaj K sa sandeep PANDA Department of Computer Science and Engineering National Institute of Technology Rourkela 769008 India

In this paper, an efficient scheme for recognition of handwritten Odia numerals using hidden markov model （HMM） has been proposed. Three different feature vectors for each of the numeral is generated through a polygonal approximation of object contour. Subsequently, aggregated feature vector for each numeral is derived from these three primary feature vectors using a fuzzy inference system. The final feature vector is divided into three levels and interpreted as three different states for HMM. Ten different three-state ergodic hidden markov models （HMMs） are thus constructed corresponding to ten numeral classes and parameters are calculated from these models. For the recognition of a probe numeral, its log-likelihood against these models are computed to decide its class label. The proposed scheme is implemented on a dataset of 2500 handwritten samples and a recognition accuracy of 96.3% has been achieved. The scheme is compared with other competent schemes.

关键词： handwritten character recognition HMM pattern recognition Odia numeral OCR

salinity Distribution at Canal Istanbul and Its Possible Impacts on the Northern Marmara Sea

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China Ocean Engineering 2020年第6期34卷 881-888页

作者： Şehriban sa.u Tarkan ERDIK OlgayŞEN Istanbul Technical university MaslakIstanbul 34467Turkey

Turkey has announced its plan to construct a new waterway, Canal Istanbul, parallel to the Bosphorus. In this study,the influence of Canal Istanbul on salinity distribution in the northern Marmara Sea is investigated using a previously calibrated 3 D hydrodynamic and salinity model. Moreover, the salinity field of the canal and its propagation are examined based on various meteorological cases. Finally, the flow structure of the canal is determined. It is calculated that at the southern end of the canal, mainly unidirectional flow(from the Black Sea to the Marmara Sea)occurs during 68% of the simulation period. A two-layer flow is seen only 28% of the time with a weak lower layer flow, whereas this value decreases to 4% at the north end of the canal. In the southward direction(to the Marmara Sea), velocities higher than 1.5 m/s are rarely observed along the canal. The average surface salinity difference in the northern Marmara Sea due to the construction of the canal is calculated to be smaller than 0.50 ppt. The salinity difference gradually diminishes as water depth increases and after 25 m(from the surface) almost no difference is observed.

关键词： Canal Istanbul Marmara Sea salinity distribution hydrodynamic modeling

Prehospital transdermal glyceryl trinitrate for ultra- acute ischaemic stroke: data from the RIGHT- 2 randomised sham- controlled ambulance trial

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Stroke & Vascular Neurology 2024年第1期9卷 38-49,I0035-I0046页

作者： Jason Philip Appleton Lisa J Woodhouse Craig S Anderson sandeep Ankolekar Lesley Cala Mark Dixon Timothy J England Kailash Krishnan Grant Mair Keith W Muir John Potter Christopher I Price Marc Randall Thompson G Robinson Christine Roffe Else C sandset Jeffrey L saver Angela Shone Aloysius Niroshan Siriwardena Joanna M Wardlaw Nikola Sprigg Philip M Bath Stroke University Hospitals Birmingham NHS Foundation TrustBirminghamUK Institute of Applied HealthResearch University of Birmingham College of Medical and Dental SciencesBirminghamUK Stroke Trials unit Mental Health and Clinical NeurosciencesUniversity of NottinghamNottinghamUK Faculty of Medicine The George Institute for Global HealthSydneyNew South WalesAustralia The George Institute China at Peking university Health Science Center BeijingChina Neurology Royal Prince Alfred HospitalSydney Health PartnersSydneyNew South WalesAustralia Department of Neurology King's College Hospital NHS Foundation TrustLondonUK Faculty of Health and Medical Sciences University of Western AustraliaCrawleyWestern AustraliaAustralia East Midlands Ambulance Service NHS Trust NottinghamUK Stroke Queen's Medical CentreNottingham University Hospitals NHS TrustNottinghamUK Centre for Clinical Brain Sciences Dementia Research InstituteUniveristy of EdinburghEdinburghUK Institute of Neurology and Psychology University of GlasgowGlasgowUK Bob Champion Research and Education Building University of East AngliaNorwichUK Institute of Neuroscience Newcastle UniversityNewcastle upon TyneUK Department of Neurology Leeds Teaching Hospitals NHS TrustLeedsUK Department of Cardiovascular Sciences and NIHR Leicester Biomedical Research Centre University of LeicesterLeicesterUK Stroke Research in Stoke Institute for Science and Technology in MedicineKeele UniversityStoke-on TrentUK Department of Neurology Oslo University HospitalOsloNorway Research and Development Norwegian Air Ambulance FoundationOsloNorway Department of Neurology and Comprehensive Stroke Center David Geffen School of MedicineUCLALos AngelesCaliforniaUSA Research and Graduate Services University of NottinghamNottinghamUK Community and Health Research unit University of LincolnLincolnUK

Background The effect of transdermal glyceryl trinitrate(GTN,a nitrovasodilator)on clinical outcome when administered before hospital admission in suspected stroke patients is ***,we assess the safety and efficacy of GTN in the prespecified subgroup of patients who had an ischaemic stroke within the Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2(RIGHT-2).Methods RIGHT-2 was an ambulance-based multicentre sham-controlled blinded-endpoint study with patients randomised within 4hours of *** primary outcome was a shift in scores on the modified Rankin scale(mRS)at day *** outcomes included death;a global analysis(Wei-Lachin test)containing Barthel Index,EuroQol-5D,mRS,telephone interview for cognitive status-modified and Zung depression scale;and neuroimaging-determined‘brain frailty’*** were reported as n(%),mean(SD),median[IQR],adjusted common OR(acOR),mean difference or Mann-Whitney difference(MWD)with 95%*** 597 of 1149(52%)patients had a final diagnosis of ischaemic stroke;age 75(12)years,premorbid mRS>2107(18%),Glasgow Coma Scale 14(2)and time from onset to randomisation 67[45,108]***‘brain frailty’was common:median score 2[2,3](range 0–3).At day 90,GTN did not influence the primary outcome(acOR for increased disability 1.15,95%CI 0.85 to 1.54),death or global analysis(MWD 0.00,95%CI-0.10 to 0.09).In subgroup analyses,there were non-significant interactions suggesting GTN may be associated with more death and dependency in participants randomised within 1hour of symptom onset and in those with more severe *** In patients who had an ischaemic stroke,ultra-acute administration of transdermal GTN in the ambulance did not improve clinical outcomes in a population with more clinical and radiological frailty than seen in previous in-hospital *** IS ALREADY KNOWN ON THIS TOPIC⇒Transdermal glyceryl trinitrate(GTN)was associat-ed with less death and dependency in those w

关键词： Glasgow nitrate random

Protracted zircon growth in migmatites and In situ melt of Higher Himalayan Crystallines:u-Pb ages from Bhagirathi valley, NW Himalaya,India

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Geoscience Frontiers 2019年第3期10卷 793-809页

作者： sandeep Singh Department of Earth Sciences Indian Institute of Technology Roorkee

The Higher Himalayan Crystallines(HHC), in western Garhwal, uttarakhand are located in a regionalscale intracontinental ductile shear zone(15-20 km wide) bounded by the Main Central Thrust at the base, and the South Tibetan Detachment System at the top. The migmatite zone in the centre has the highest grade of metamorphism in the NW Himalayas and show evidence of flowage. Zircons extracted from samples of metasediment, migmatite, biotite granite and in situ partial melt(tourmaline-bearing leucogranite) along the Bhagirathi Valley, preserve u-Pb isotopic evidence of magmatic history, magma source and effects of the Himalayan orogeny in the region. Three distinct periods of zircon growth in the leucogranite record the episodic influx of magma between 46 Ma and 20 Ma indicating a time span of more than 25 Ma between the onset of fluid-fluxed partial melting in the mid-crustal intracontinental shear zone and the emplacement of the magma into the upper crust in a post-collisional extensional setting. Metamorphic zircon growth was initiated about 46 Ma, when the partial melts were generated as the migmatite zone was exhumed.

关键词： Himalayas Crustal anatexis Zircon SHRIMP u-Pb dating Migmatites Granites

Micromechanical experiments using a new inter-granule loading apparatus on gravel to ballast-sized materials

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Friction 2020年第1期8卷 70-82页

作者： Chitta sai sandeep Kostas SENETAKIS City university of Hong Kong Hong Kong SARChina

Micromechanical and tribological studies of geological materials with a particular focus on their contact-mechanics behavior at the grain scale are currently a major interest in the engineering and geoscience disciplines. In this study, a new robust micromechanical apparatus developed at the City university of Hong Kong is described;it is capable of conducting inter-granule(or inter-particle) loading tests on fine gravel to ballast-sized materials of sizes as small as 5-10 mm to granules(or ballast) as big as 50 mm. The focus of our study is the description of the major technical features of the new apparatus and its performance and repeatability in conducting experiments on reference grains of chrome steel balls and glass balls;in addition, we conducted a preliminary set of experiments on crushed granitic rock, which is a material widely used in geotechnical and transportation infrastructure. The representative results of these experiments are presented in terms of the normal force-displacement relationship, friction, and tangential stiffness. The newly developed large-size apparatus is further compared with a well-established apparatus that can conduct micromechanical tests on sand-sized materials.

关键词： experimental micromechanics contact mechanics linear bearings inter‐particle friction granite debris flow ballast

Evaluation of phenolic composition, antioxidant, anti-inflammatory and anticancer activities of Polygonatum verticillatum(L.)

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Journal of Integrative Medicine 2018年第4期16卷 273-282页

作者： sandeep kuma. Singh Arjun Patra Institute of Pharmacy Guru Ghasidas University

Objective： Polygonaturn verticillatum （L） All. （Ruscaceae）, one of the Ashtawarga plants, is widely used for treatment of various ailments. The present study was undertaken to determine the phenolic composition, antioxidant, anti-inflammatory and anticancer activities of several extracts （petroleum ether, dichloro- methane, chloroform, ethanol, and aqueous） from the rhizomes of the plant. Methods： Coarsely powdered dry rhizome was successively extracted with different solvents of increas- ing polarity （petroleum ether, dichloromethane, chloroform, ethanol and water）. The phenolic composi- tions, in terms of total phenolic content （TPC）, total flavonoid content （TFC） and total condensed tannin content （JTC）, were evaluated with the Folin-Ciocalteu assay, aluminum chloride colorimetric assay and vanillin spectrophotometric assay, respectively. Total antioxidant capacity, 1,1-diphenyl-2- picrylhydrazyl and 2,2＇-azino-his（3-ethylbenzothiazoline-6-sulfonic acid） assays were used to assess the antioxidant potential of each extract. A protein denaturation model and 3-（4,5-dimethylthiazol-2- yl）-2,5-diphenyltetrazolium bromide assay were used to evaluate in vitro anti-inflammatory and anti- cancer activities, respectively. Gas chromatography-mass spectrometry （GC/MS） analysis was carried out to demonstrate various phytoconstituents in each extract. Correlation studies were also performed between phenolic composition （TPC, TFC and TFC） and different biological activities. Results： Ethanol extract showed maximum TPC （0.126 mg/g, gallic acid equivalent in dry sample）, TFC （0.094 mg/g, rutin equivalent in dry sample） and TTC （29.32 mg/g, catechin equivalent in dry sample）, as well as antioxidant and anti-inflammatory properties. Chloroform extract exhibited the strongest cyto- toxicity against the human breast cancer cell line, MCF-7. GC/MS analysis revealed the presence of 90 different phytoconstituents among the extracts. Antioxidant and anti-inflammatory activities had a pos

关键词： Polygonatum verticillatum Gas chromatography-mass spectrometry Phenolic profile MCF-7 cells