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Characterization of multi-scale ionospheric irregularities using ground-based and space-based GNSS observations

Satellite Navigation 2021年第1期2卷 192-212页

作者： YuXiang Peng Wayne A Scales michael d hartinger Zhonghua Xu Shane Coyle Center for Space Science and Engineering Research Virginia TechBlacksburgVA 24061USA Bradley department of Electrical and Computer Engineering Virginia TechBlacksburgVA 24061USA Space Science Institute BoulderCO 80301USA National Institute of Aerospace HamptonVA 23666USA Center for Space Science and Engineering Research Virginia TechBlacksburgVA 24061USA.

Ionospheric irregularities can adversely affect the performance of Global Navigation Satellite System (GNSS). How-ever, this opens the possibility of using GNSS as an effective ionospheric remote sensing tool. despite ionospheric monitoring has been undertaken for decades, these irregularities in multiple spatial and temporal scales are still not fully understood. This paper reviews Virginia Tech’s recent studies on multi-scale ionospheric irregularities using ground-based and space-based GNSS observations. First, the relevant background of ionospheric irregularities and their impact on GNSS signals is reviewed. Next, three topics of ground-based observations of ionospheric irregulari-ties for which GNSS and other ground-based techniques are used simultaneously are reviewed. Both passive and active measurements in high-latitude regions are covered. Modelling and observations in mid-latitude regions are considered as well. Emphasis is placed on the increased capability of assessing the multi-scale nature of ionospheric irregularities using other traditional techniques (e.g., radar, magnetometer, high frequency receivers) as well as GNSS observations (e.g., Total-Electron-Content or TEC, scintillation). Besides ground-based observations, recent advances in GNSS space-based ionospheric measurements are briefly reviewed. Finally, a new space-based ionospheric observa-tion technique using GNSS-based spacecraft formation flying and a differential TEC method is demonstrated using the newly developed Virginia Tech Formation Flying Testbed (VTFFTB). Based on multi-constellation multi-band GNSS, the VTFFTB has been developed into a hardware-in-the-loop simulation testbed with external high-fidelity global ionospheric model(s) for 3-satellite formation flying, which can potentially be used for new multi-scale ionospheric measurement mission design.

关键词： GNSS Ionospheric irregularities Remote sensing Active experiment Spacecraft formation flying

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Transmission Line Modelling of Geomagnetic Induction in the Ocean/Earth Conductivity Structure

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International Journal of Geosciences 2023年第8期14卷 767-791页

作者： david H. Boteler Shibaji Chakraborty Xueling Shi michael d. hartinger Xuan Wang Geomagnetic Laboratory Natural Resources Canada Ottawa Canada Center for Space Science and Engineering Research Virginia Tech Blacksburg USA High Altitude Observatory National Center for Atmospheric Research Boulder USA Space Science Institute Boulder USA department of Electrical Engineering Tsinghua University Beijing China

during geomagnetic disturbances, electric fields induced in the Earth and in power systems, pipelines and submarine cables can interfere with the operation of these systems. Calculations for submarine cables are complicated by the need to consider not just the induction directly into the cable but also the earth potentials produced at the coast at each end of the cable. To determine the coast potentials, we present a new model of the ocean and earth conductivity structure that spans the whole length of a cable from one coast to another. Calculations are based on the generalised thin sheet approach introduced by Ranganayaki and Madden but converted to a transmission line model that can be solved using standard circuit theory techniques. It is shown how the transmission line model can be used to calculate the earth potential profile from one side of an ocean or sea to the other. Example calculations are presented for a shallow sea, a shallow ocean, and a deep ocean that are simplified approximations to the North Sea, Tasman Sea and Pacific Ocean and show that the peak potentials occur at the coast. An examination is also made of how the width of a shallow sea and the width of the continental shelf affect these coast potentials. The modelling technique and example results provide a guide for more detailed modelling of geomagnetic induction along the routes of specific submarine cables.

关键词： Geomagnetic Induction Generalised Thin Sheet Transmission Line Modelling Coast Potentials Submarine Cables

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Microscale shaping and rounding of ridge arrays and star pattern features on nickel mould via electrochemical polishing

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Advances in Manufacturing 2024年第2期12卷 207-226页

作者： Sana Zaki Nan Zhang michael d.Gilchrist School of Mechanical and Materials Engineering University College DublinBelfieldDublin 4Ireland

High quality micro mould tools are critical for ensuring defect-free production of micro injection moulded *** demoulding stage of the micro injection moulding can adversely affect the surface integrity due to friction,adhesion and thermal stresses between the metallic mould and polymeric replicated *** the present work,we propose the use of precision electropolishing(EP)as a shaping and polishing process to control the draft angle and fillet radius of micro features in order to ease *** defects that occur in replicated polymer parts include cracks,burrs and distorted features.A nickel mould having multiple linear ridges and star shape patterns was designed for the present investigation to have characteristic dimensions ranging from 10μm to 150μm and with various aspect ratios to study the effect of electropolishing on modifying the shape of micro features and surface morphology.A transient 2d computational analysis has been conducted to anticipate the effect of shaping on the Ni mould after electrochemical polishing with non-uniform material removal rates,based on the distribution of current *** experimental results indicate that after shaping using EP,the draft angle of star-patterns and linear patterns can be effectively increased by approximately 3.6°,while the fillet radius increases by up to 5.0μ*** controlling the electropolishing process,the surface roughness can be maintained under 50 *** work uses a green and environmental friendly nickel sulfamate electrolyte which can be effective for shaping of nickel micro features without causing any surface deposition.

关键词： Micro feature shaping and electropolishing Micro mould tools Green electrolyte demoulding micro patterns

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BMPRⅡ^(+)neural precursor cells isolated and characterized from organotypic neurospheres:an in vitro model of human fetal spinal cord development

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Neural Regeneration Research 2024年第2期19卷 447-457页

作者： michael W.Weible II michael d.Lovelace Hamish d.Mundell Tsz Wai Rosita Pang Tailoi Chan-Ling Bosch Institute Discipline of Anatomy and Histology(F13)University of SydneySydneyNSWAustralia School of Environment and Science Griffith UniversityNathanQLDAustralia discipline of Medicine Nepean Clinical SchoolFaculty of Medicine and HealthUniversity of SydneyKingswoodNSWAustralia New South Wales Brain Tissue Resource Centre School of Medical SciencesFaculty of Medicine and HealthUniversity of SydneyCharles Perkins Centre(D17)SydneyNSWAustralia

Roof plate secretion of bone morphogenetic proteins(BMPs)directs the cellular fate of sensory neurons during spinal cord development,including the formation of the ascending sensory columns,though their biology is not well ***-ⅡBMP receptor(BMPRⅡ),the cognate receptor,is expressed by neural precursor cells during embryogenesis;however,an in vitro method of enriching BMPRⅡ^(+)human neural precursor cells(hNPCs)from the fetal spinal cord is *** was undertaken on intact second-trimester human fetal spinal cord using antibodies to BMPRⅡand leukemia inhibitory factor(LIF).Regions of highest BMPRⅡ^(+)immunofluorescence localized to sensory *** and meningeal-associated BMPRⅡ^(+)vascular cells were identified in both intact fetal spinal cord and cortex by co-positivity with vascular lineage markers,Cd34/*** immunostaining identified a population of somas concentrated in dorsal and ventral horn interneurons,mirroring the expression of LIF receptor/Cd118.A combination of LIF supplementation and high-density culture maintained culture growth beyond 10 passages,while synergistically increasing the proportion of neurospheres with a stratified,*** neurospheres were characterized by BMPRⅡ^(+)/MAP2ab^(+/–)/βⅢ-tubulin^(+)/nestin^(–)/vimentin^(–)/GFAP^(–)/NeuN^(–)surface hNPCs surrounding a heterogeneous core ofβⅢ-tubulin^(+)/nestin^(+)/vimentin^(+)/GFAP^(+)/MAP2ab^(–)/NeuN^(–)multipotent *** cultures from tripotential neurospheres contained neuronal(βⅢ-tubulin^(+)),astrocytic(GFAP+),and oligodendrocytic(O4+)lineage ***-activated cell sorting-sorted BMPRⅡ^(+)hNPCs were MAP2ab^(+/–)/βⅢ-tubulin^(+)/GFAP^(–)/O4^(–)in *** is the first isolation of BMPRⅡ^(+)hNPCs identified and characterized in human fetal spinal *** data show that LIF combines synergistically with high-density reaggregate cultures to support the organotypic reorganization of neurospheres,characterize

关键词： BMPRⅡ bone morphogenetic protein histotypic human spinal cord development leukemia inhibitory factor neurosphere organotypic reaggregate sensory columns

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Importance-aware 3d volume visualization for medical content-based image retrieval-a preliminary study

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虚拟现实与智能硬件（中英文） 2024年第1期6卷 71-81页

作者： Mingjian LI Younhyun JUNG michael FULHAM Jinman KIM School of Computer Science The University of SydneySydneyNSW 2006Australia School of Computing Gachon UniversitySeongnam 13120South Korea department of Molecular Imaging Royal Prince Alfred HospitalSydneyNSW 2050Australia

Background A medical content-based image retrieval(CBIR)system is designed to retrieve images from large imaging repositories that are visually similar to a user′s query *** is widely used in evidence-based diagnosis,teaching,and *** the retrieval accuracy has largely improved,there has been limited development toward visualizing important image features that indicate the similarity of retrieved *** the prevalence of 3d volumetric data in medical imaging such as computed tomography(CT),current CBIR systems still rely on 2d cross-sectional views for the visualization of retrieved *** 2d visualization requires users to browse through the image stacks to confirm the similarity of the retrieved images and often involves mental reconstruction of 3d information,including the size,shape,and spatial relations of multiple *** process is time-consuming and reliant on users'*** In this study,we proposed an importance-aware 3d volume visualization *** rendering parameters were automatically optimized to maximize the visibility of important structures that were detected and prioritized in the retrieval *** then integrated the proposed visualization into a CBIR system,thereby complementing the 2d cross-sectional views for relevance feedback and further *** Our preliminary results demonstrate that 3d visualization can provide additional information using multimodal positron emission tomography and computed tomography(PETCT)images of a non-small cell lung cancer dataset.

关键词： Volume visualization dVR Medical CBIR Retrieval Medical images

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“digitalMe”in smart cities

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The Innovation 2024年第5期5卷 11-12页

作者： Seung-min Park Seunghun Hong Kyonghee Joo Soh Kim michael d.Lepech School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological UniversitySingapore 637459Singapore Walmart Connect HobokenNJ 07030USA LG CNS Seoul 07795South Korea department of Civil and Environmental Engineering Stanford UniversityStanfordCA 94305USA Stanford Center at the Incheon Global Campus(SCIGC) IncheonSouth Korea

PRECISION HEALTH ANd *** Continuous monitoring of high-value equipment,such as semiconductor production equipment and jet airplane engines,has become a standard practice across myriad commercial sectors.“digital twin”technologies enable such monitoring by providing sensor data for maintenance and other mission-critical operations in real *** continuous monitoring has become standard in some industry,its application to monitoring healthy adults globally remains underexplored,with many individuals seeking medical care only when *** gained from digital twin could be transferred to healthcare,revealing opportunities for more data-driven and personalized care.

关键词： gained seeking smart

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Fabrication of sub-20 nm MoS_(2) horizontal nanowire on silicon substrates by inclusion of precursors into polystyrene-bpolyethylene oxide nanopatterns: detailed structural investigation

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Nano Research 2024年第3期17卷 2145-2153页

作者： Tandra Ghoshal michael A.Morris School of Chemistry AMBER and CRANNTrinity College DublinDublinIrelandD02 AK60

Herein,we demonstrate the fabrication of sub-20 nm MoS_(2) horizontal nanowire arrays on silicon substrates using a self-assembled block copolymer assisted in situ inclusion *** separated long-range ordered polystyrene-b-polyethylene oxide(PS-b-PEO)block copolymer(BCP)line-space nanopatterns were achieved through thermo-solvent *** patterns produced had long-range order and domain sizes>1μ*** BCP structures were lightly etched and modified by anhydrous ethanol to facilitate insertion of molybdenum precursor within the film maintaining the parent BCP *** ordered molybdenum oxide nanowire arrays were then fabricated by ultraviolet(UV)/ozone treatment at room *** oxides were converted to sulphides by thermal evaporation at different temperatures in Ar/H_(2) environment.X-ray photoelectron spectroscopy revealed the composition and phases of the molybdenum oxide and sulphide *** mapping was performed to investigate the interfaces between the oxide and sulphide nanowires with the substrate *** formation and stability of the sulphide nanowires were studied at different *** photoluminescence and Raman properties were studied at different formation temperatures to investigate defects and estimate the number of layers.

关键词： MoS_(2) block copolymer nanowires inclusion X-ray photoelectron spectroscopy(XPS) mapping photoluminescence

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A shoe-box-sized 3d laser nanoprinter based on two-step absorption

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Light(Advanced Manufacturing) 2024年第2期5卷 115-122页

作者： Tobias Messer michael Hippe Jingya(Lilyn)Gao Martin Wegener Institute of Applied Physics(APH) Karlsruhe Institute of Technology(KIT)76128 KarlsruheGermany Institute of Nanotechnology(INT) Karlsruhe Institute of Technology(KIT)76128 KarlsruheGermany

State-of-the-art commercially available 3d laser micro-and nanoprinters using polymeric photoresists based on two-or multi-photon absorption rely on high-power pico-or femtosecond lasers,leading to fairly large and expensive ***,we have introduced photoresists based on two-step absorption instead of two-photon absorption,allowing for the use of small and inexpensive continuous-wave 405 nm wavelength GaN semiconductor laser diodes with light-output powers below 1 ***,using the identical photoresist system and similar laser diodes,we report on the design,construction,and characterization of a 3d laser nanoprinter that fits into a shoe *** shoe box contains all optical components,namely the mounted laser,the collimation-and beam-shaping optics,a miniature MEMS xy-scanner,a tube lens,the focusing microscope objective lens(NA=1.4,100×magnification),a piezo slip-stick z-stage,the sample holder,a camera monitoring system,LEd sample illumination,as well as the miniaturized control electronics employing a *** present a gallery of example 3d structures printed with this *** achieve about 100 nm lateral spatial resolution and focus scan speeds of about 1 mm/***,our shoe-box-sized system can be made orders of magnitude less expensive than today’s commercial systems.

关键词： Two-step absorption direct laser writing 3d laser nanoprinters Micro-electro-mechanical-systems scanner 3d nanostructures

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Injury and illness in short-course triathletes:A systematic review

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Journal of Sport and Health Science 2024年第2期13卷 172-185页

作者： Sara A.Guevara Melissa L.Crunkhorn michael drew Gordon Waddington Julien d.Périard Naroa Etxebarria Liam A.Toohey Paula Charlton University of Canberra Research Institute for Sport and Exercise(UCRISE) BruceACT 2617Australia New South Wales Institute of Sport SydneyNSW 2127Australia Queensland Academy of Sport BrisbaneQLD 4111Australia Triathlon Australia Gold CoastQLD 4227Australia Australian Institute of Sport BruceACT 2617Australia

Background:determining the incidence and prevalence of injury and illness in short-course triathletes would improve understanding of their etiologies and therefore assist in the development and implementation of prevention *** study synthesizes the existing evidence on the incidence and prevalence of injury and illness and summarizes reported injury or illness etiology and risk factors affecting short-course ***:This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses *** reporting health problems(injury and illness)in triathletes(all sexes,ages,and experience levels)training and/or competing in short-course distances were *** electronic databases(Cochrane Central Register of Controlled Trials,MEdLINE,Embase,APA PsychINFO,Web of Science Core Collection,and SPORTdiscus)were *** of bias was independently assessed by 2 reviewers using the Newcastle-Ottawa Quality Assessment *** authors independently completed data ***:The search yielded 7998 studies,with 42 studies eligible for ***-three studies investigated injuries,24 studies investigated illnesses,and 5 studies investigated both injuries and *** injury incidence rate ranged 15.7-24.3 per 1000 athlete exposures,and the illness incidence rate ranged 1.8-13.1 per 1000 athlete *** and illness prevalence ranged between 2%-15%and 6%-84%,*** injuries reported occurred during running(45%-92%),and the most frequently reported illnesses affected the gastrointestinal(7%-70%),cardiovascular(14%-59%),and respiratory systems(5%-60%).Conclusion:The most frequently reported health problems in short-course triathletes were:overuse and lower limb injuries associated with running;gastrointestinal illnesses and altered cardiac function,primarily attributable to environmental factors;and respiratory illness mostly caused by infection.

关键词： Athlete illnesses Athletic injuries Epidemiology Triathlon

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Phrenic nerve block: the key to managing acute biliary pain?

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World Journal of Emergency Medicine 2024年第1期15卷 62-63页

作者： michael Shalaby Joshua Luftig department of Emergency Medicine and Critical Care Herbert Wertheim College of Medicine at Florida International UniversityMiami 33199USA Advanced Emergency Ultrasound Mount Sinai Medical CenterMiami Beach 33140USA department of Emergency Medicine Highland HospitalAlameda Health SystemOakland 94602USA

Over the past two decades,the USA has witnessed a steep rise in the incidence of acute cholecystitis(AC),[1]even among children,[2]with over 200,000 cases annually.[3]Patients with AC often present to the emergency department(Ed)experiencing severe distress,with most describing their pain level as“intolerable.”[4]Furthermore,there is usually a considerable delay before surgery,with a median time from diagnosis of AC to surgery of 28.5 h,[5]and a substantial percentage of patients wait as long as 10 d.[6]Prolonged delays before surgery lead to increased opioid use,which is associated with extended hospital stays and higher rates of readmission after cholecystectomy.[7]Furthermore,opioids can lead to vomiting,respiratory depression,delirium,and ultimately addiction.[8]We propose a novel regional anesthesia technique for managing AC:right phrenic nerve *** method could offer improved pain control and a more favorable risk profile in selected patients when compared to current Ed practices.

关键词： pain anesthesia diagnosis

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