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Distinct vibrational signatures and complex phase behavior in metallic oxygen

Matter and Radiation at Extremes 2024年第2期9卷 4-11页

作者： philip Dalladay-Simpson Bartomeu Monserrat Li Zhang Federico Gorelli Center for High Pressure Science Technology Advanced Research 1690 Cailun RoadShanghai 201203China Department of Materials Science and Metallurgy University of Cambridge27 Charles Babbage RoadCambridge CB3 OFSUnited Kingdom Cavendish Laboratory University of CambridgeJ.J.Thomson AvenueCambridge CB3 OHEUnited Kingdom Istituto Nazionale di Ottica Consiglio Nazionale delle Ricerche(CNR-INO)50125 FlorenceItaly Shanghai Advanced Research in Physical Sciences(SHARPS) ShanghaiChina

Evidence for metallization in dense oxygen has been reported for over 30 years[Desgreniers et al.,***.94,1117(1990)]at a now routinely accessible 95 GPa[Shimizu et al.,Nature 393,767(1998)].However,despite the longevity of this result and the technological advances since,the nature of the metallic phase remains poorly constrained[Akahama et al.,***.74,4690(1995);Goncharov et al.,***.B 68,224108(2003);Ma,***.B 76,064101(2007);and Weck et al.,***.102,255503(2009)].In this work,through Raman spectroscopy,we report the distinct vibrational characteristics of metallicζ-O_(2) from 85 to 225 *** comparison with numerical simulations,weﬁnd reasonable agreement with the candidate structure up to about 150 *** higher pressures,the C2/mstructure is found to be unstable and incompatible with experimental *** candidate structures,and Ci,with C2/m C2/conly two molecules in the primitive unit cell,are found to be stable and more compatible with measurements above 175 GPa,indicative of the dissociation of(O_(2))4 ***,we report and discuss a strong hysteresis and metastability with the precursory phaseϵ-O_(2).Theseﬁndings will reinvigorate experimental and theoretical work into the dense oxygen system,which will have importance for oxygen-bearing chemistry,prevalent in the deep Earth,as well as fundamental physics.

关键词： metallic phase vibrational

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Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

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Science China(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia ZHAO jiale WU Zhijie LIU We HE C.L.philip CHEN School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key Laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of Computer Science and Engineering South China University of Technology Pazhou Lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

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Hydromechanical characterization of gas transport amidst uncertainty for underground nuclear explosion detection

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journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2019-2032页

作者： Wenfeng Li Chelsea W.Neil j William Carey Meng Meng Luke P.Frash philip H.Stauffer Earth and Environmental Sciences Los Alamos National LaboratoryLos AlamosNM87544USA Department of Mineral Engineering New Mexico TechSocorroNM87801USA

Given the challenge of definitively discriminating between chemical and nuclear explosions using seismic methods alone,surface detection of signature noble gas radioisotopes is considered a positive identification of underground nuclear explosions(UNEs).However,the migration of signature radionuclide gases between the nuclear cavity and surface is not well understood because complex processes are involved,including the generation of complex fracture networks,reactivation of natural fractures and faults,and thermo-hydro-mechanical-chemical(THMC)coupling of radionuclide gas transport in the *** this study,we provide an experimental investigation of hydro-mechanical(HM)coupling among gas flow,stress states,rock deformation,and rock damage using a unique multi-physics triaxial direct shear rock testing *** testing system also features redundant gas pressure and flow rate measurements,well suited for parameter uncertainty *** porous tuff and tight granite samples that are relevant to historic UNE tests,we measured the Biot effective stress coefficient,rock matrix gas permeability,and fracture gas permeability at a range of pore pressure and stress *** Biot effective stress coefficient varies from 0.69 to 1 for the tuff,whose porosity averages 35.3%±0.7%,while this coefficient varies from 0.51 to 0.78 for the tight granite(porosity<1%,perhaps an underestimate).Matrix gas permeability is strongly correlated to effective stress for the granite,but not for the porous *** experiments reveal the following key engineering implications on transport of radionuclide gases post a UNE event:(1)The porous tuff shows apparent fracture dilation or compression upon stress changes,which does not necessarily change the gas permeability;(2)The granite fracture permeability shows strong stress sensitivity and is positively related to shear displacement;and(3)Hydromechanical coupling among stress states,rock damage,and gas flow appears to be

关键词： Underground nuclear explosion uncertainty quantification Radionuclide transport Biot effective stress coefficient Fracture permeability Matrix permeability

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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

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The Effects of Zinc Sulfate on the in Vitro Digestibility of Feeds in Cervids

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Open journal of Animal Sciences 2024年第3期14卷 157-167页

作者： Reese j. Thibodeaux philip M. Urso Stanley F. Kelley Marcy M. Beverly Chris R. Stewart Ian C. Dunn Gentech Diagnostics Dallas Texas USA Department of Animal Science South Dakota State University Brookings South Dakota USA School of Agricultural Sciences Sam Houston State University Huntsville Texas USA 3-S Texas Outdoors/3-S Whitetails Bedias Texas USA

The captive white-tailed deer industry has an estimated impact of 1.6 billion USD in the state of Texas alone. However, nutritional requirements for cervids are determined through research based on sheep and goats. The objective of this study was to determine the effects of zinc on differences in dry matter digestibility in vitro for white-tailed does (Odocoileus virginianus). Deer (n = 2) were ethically harvested, rumens were collected, and placed into a cooler containing warm water. Rumen contents were agitated, and fluid was filtered using cheese cloth while applying CO2. Fluid was placed into four separate incubator jars with filter bags containing a 1:1 alfalfa to coastal hay blend. Zinc doses of 0.073 mg/kg/d equivalents were added to two of the jars ( Zn), and the additional two jars received 0.00 mg/kg/d (CON). Following 48 h of incubation, in vitro true digestibility (IVTD) showed no significant differences between the control and the treatment groups. Average dry matter digested in vitro was 91.87% and 95.13%, respectively. There were no differences detected in ADF, NDF, IVTD, or OM between the treatment groups. While no detectable differences were observed in this study, this methodology did prove to be viable and functional for microbial digestion in vitro. This study can be replicated with multiple experimental units to confirm the observations of increased digestibility. Formal nutritional guidelines can be created to allow for more efficient feeding of cervids thereby reducing feed costs and continuing the growth of the captive deer industry.

关键词： Zinc IVDMD In Vitro Cervids

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Pseudospin-2 in photonic chiral borophene

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Photonics Research 2023年第5期11卷 869-877页

作者： philip MENZ HAISSAM HANAFI DANIEL LEYKAM jÖRG IMBROCK CORNELIA DENZ Institute of Applied Physics University of MuensterMuenster 48149Germany Centre for Quantum Technologies National University of SingaporeSingapore 117543Singapore Physikalisch-Technische Bundesanstalt(PTB) 38116 BraunschweigGermany

Pseudospin is an angular momentum degree of freedom introduced in analogy to the real electron spin in the effective massless Dirac-like equation used to describe wave evolution at conical intersections such as the Dirac cones of ***,we study a photonic implementation of a chiral borophene allotrope hosting a pseudospin-2 conical intersection in its energy-momentum *** presence of this fivefold spectral degeneracy gives rise to quasiparticles with pseudospin up to±*** report on conical diffraction and pseudospin-orbit interaction of light in photonic chiral borophene,which,as a result of topological charge conversion,leads to the generation of highly charged optical phase vortices.

关键词： spectrum chiral momentum

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High-quality 8-fold self-compression of ultrashort near-UV pulses in an Ar-filled ultrathin-walled photonic crystal fiber

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Photonics Research 2022年第10期10卷 2405-2409页

作者： jIE LUAN philip ST.j.RUSSELL DAVID NOVOA Max Planck Institute for the Science of Light 91058 ErlangenGermany Department of Physics Friedrich-Alexander-Universität91058 ErlangenGermany Department of Communications Engineering Engineering School of BilbaoUniversity of the Basque Country(UPV/EHU)48013 BilbaoSpain EHU Quantum Center University of the Basque Country(UPV/EHU)48013 BilbaoSpain IKERBASQUE Basque Foundation for Science48009 BilbaoSpain Previously with the Max Planck Institute for the Science of Light 91058 ErlangenGermany

We demonstrate generation of 7.6 fs near-UV pulses centered at 400 nm via 8-fold soliton-effect self-compression in an Ar-filled hollow-core kagomé-style photonic crystal fiber with ultrathin core *** calculations of the effective compression length and soliton order permit adjustment of the experimental parameters,and numerical modeling of the nonlinear pulse dynamics in the fiber accurately predicts the spectrotemporal profiles of the self-compressed *** compensation of phase distortion introduced by the optical elements along the beam path from the fiber to the diagnostics,71%of the pulse energy was in the main temporal lobe,with peak powers in excess of 0.2 *** convenient setup opens up new opportunities for time-resolved studies in spectroscopy,chemistry,and materials science.

关键词： fiber ultrashort filled

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Surface Nanopatterning Using the Self-Assembly of Linear Polymers on Surfaces after Solvent Evaporation

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Nanomanufacturing and Metrology 2022年第3期5卷 297-309页

作者： Emmanouil Glynos Alexandros Chremos philip j.Camp Vasileios Koutsos School of Engineering Institute for Materials and ProcessesTheUniversity of EdinburghRobert Stevenson RoadEdinburgh EH93FBUK School of Chemistry The University of EdinburghDavid Brewster RoadEdinburgh EH93FJUK Department of Materials Science and Technology University of Crete71003 HeraklionGreece Section on Quanitative Imaging and Tissue Sciences Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMD 20892USA

The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in air(after rapid solvent evaporation)depends strongly on the molecular weight(Mw)of the linear polymer,the adsorbed amount,and the conformation adopted by the adsorbed polymer chains under good solvent *** dependence of the observed polymer structure on Mw is most significant for samples with high surface density,where the intermolecular interactions among the adsorbed polymers are *** high surface density,the adsorbed polymers tend to aggregate and minimize unfavorable contacts with air for all of the different Mw samples,leading to an isotropic structural *** structural phenomena with increasing surface density are explained on the basis of the intermolecular interactions of the adsorbed polymers under good solvent conditions,and after the abrupt solvent evaporation corresponding to poor solvent *** experimental observations are further discussed using the results obtained from molecular dynamics simulations of a simple coarse-grained model.

关键词： Surface nanopatterning Self-assembly Nanomanufacturing

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A Distributed Transactive Energy Mechanism for Integrating PV and Storage Prosumers in Market Operation

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Engineering 2022年第5期8卷 171-182页

作者： Peng Hou Guangya Yang junjie Hu philip j.Douglass Yusheng Xue Technical University of Denmark Kongens Lyngby 2800Denmark School of Electrical and Electronic Engineering North China Electric Power UniversityBeijing 102206China Danish Energy Frederiksberg 1900Denmark State Grid Electric Power Research Institute Nanjing 211106China

The decreasing cost of solar photovoltaics(PVs)and battery storage systems is driving their adoption in the residential distribution system,where more consumers are becoming *** this trend is the potential roll-out of home energy management systems(HEMSs),which provide a means for prosumers to respond to externalities such as energy price,weather,and energy ***,the economic operation of prosumers can affect grid security,especially when energy prices are extremely low or ***,it is paramount to design a framework that can accommodate the interests of the key stakeholders in distribution systems—namely,the network operator,prosumer,and *** this paper,a novel transactive energy(TE)-based operational framework is *** this frame-work,aggregators interact with the distribution grid operator through a negotiation process to ensure network security,while at the lower level,prosumers submit their schedule to the aggregator through the *** network security is at risk,aggregators will send an additional price component representing the cost of security(CoS)to the prosumer to stimulate further *** simulation results show that the proposed framework can effectively ensure the economic operation of aggregators and prosumers in distribution systems while maintaining grid security.

关键词： Demand management Prosumer Transactive energy Aggregator Grid security

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The Shishugou Fauna of the Middle-Late jurassic Transition Period in the junggar Basin of Western China

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Acta Geologica Sinica(English Edition) 2022年第4期96卷 1115-1135页

作者： XU Xing james M.CLARK David A.EBERTH philip j.CURRIE Centre for Vertebrate Evolutionary Biology Yunnan UniversityKunming 650500China Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China Department of Biological Sciences George Washington UniversityWashington DC20052USA Royal Tyrrell Museum of Palaeontology Box 7500DrumhellerAlberta T0J 0Y0Canada Department of Biological Sciences University of Alberta 116 Street and 85 AvenueEdmontonAB T6G 2R3Canada

The Middle-Late jurassic transition period is a critical period for the evolution of terrestrial vertebrates,but the global fossil record from this time is relatively *** Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups,some representing the earliest known members of several dinosaurian groups and other vertebrate groups and some representing the best-known specimens of their *** discoveries are significant for our understanding of the origin and evolution of several vertebrate *** dating indicates that the fauna is aged approximately 159-164 *** with other similarly-aged terrestrial faunas such as Shaximiao and Yanliao show both taxonomic similarities and differences between these faunas and indicate that the junggar deposits might have preserved the most complete vertebrate fossil record for a Middle-Late jurassic Laurasian terrestrial fauna.

关键词： Middle-Late jurassic Shishugou Fauna Shishugou Formation terrestrial ecosystem Shaximiao Yanliao junggar Basin

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