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Real-time noise-free inline self-interference incoherent digital holography with temporal geometric phase multiplexing

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Photonics Research 2023年第6期11卷 906-916页

作者： KIHONG CHOI jae-WON LEE JUNGYEOP SHIN KEEHOON HONG JOONGKI park HAK-RIN KIM Digital Holography Research Section Electronics and Telecommunications Research InstituteDaejeon 34129Republic of Korea School of Electronic and Electrical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea School of Electronics Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

In this paper,we propose a real-time incoherent digital holographic(IDH)recording system free from bias and twin-image noises.A motionless three-step polarization-encoded phase-shifter operating at 99 Hz is realized with two electrically controllable birefringence-mode liquid crystal cells operating in tandem with a geometric phase lens and *** on the proposed optical configuration,a coaxial straight-line self-interference IDH recording system is ***,the elimination of bias and twin-image noise from three phase-shifted images is demonstrated as a proof of ***,complex-valued holographic video acquisitions with a resolution greater than 20 megapixels are demonstrated,with an effective acquisition frequency of33 Hz.

关键词： holographic phase geometric

Comparative study of extrudability, microstructure, and mechanical properties of AZ80 and BA53 alloys

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Journal of Magnesium and Alloys 2023年第1期11卷 249-258页

作者： Sang-Cheol Jin jae Won Cha Jongbin Go Jun Ho Bae Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Kyoto UniversityKyoto 606-8501Japan Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The extrudability,microstructural characteristics,and tensile properties of the Mg–5Bi–3Al(BA53)alloy are investigated herein by comparing them with those of a commercial Mg–8Al–0.5 Zn(AZ80)*** AZ80 is extruded at 400℃,severe hot cracking occurs at exit speeds of 4.5 m/min or *** contrast,BA53 is successfully extruded without any surface cracking at 400℃ and at high exit speeds of 21–40 m/*** extruded at 3 m/min(AZ80–3)and 40 m/min(BA53–40),both AZ80 and BA53 exhibited completely recrystallized microstructures with abasal ***,BA53–40 has a coarser grain structure owing to grain growth promoted by the high temperature in the deformation ***80–3 contains a continuous network of Mg_(17)Al_(12) particles along the grain boundaries,which form via static precipitation during natural air-cooling after the material exits the extrusion ***53–40 contains coarse Mg_(3)Bi_(2) particles aligned parallel to the extrusion direction along with numerous uniformly distributed fine Mg_(3)Bi_(2) ***80–3 has higher tensile strength than BA53–40 because the relatively finer grains and larger number of solute atoms in AZ80–3 result in stronger grain-boundary and solid-solution hardening effects,*** BA53 is extruded at a high temperature and extrusion speed of 400℃ and 40 m/min,respectively,the extruded material has a high tensile yield strength of 188 *** can be primarily attributed to the large particle hardening effect resulting from the numerous fine Mg_(3)Bi_(2) particles.

关键词： Mg-Bi-Al alloy Extrusion Hot cracking Second phase Tensile properties

Effects of Al addition on microstructure and mechanical properties of extruded Mg-3Bi alloy

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Journal of Magnesium and Alloys 2022年第7期10卷 1887-1898页

作者： Sang-Cheol Jin jae Won Cha Jun Ho Bae Hui Yu Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea School of Materials Science and Engineering Hebei University of TechnologyTianjin 300130China

Effects of Al addition to a Mg±Bi binary alloy on its microstructural characteristics and tensile properties after extrusion are investigated via extrusion of Mg-3Bi±x Al(x=0,1,and 2 wt%)billets and analysis of the extruded *** Al addition negligibly affects the second-phase particles of the extruded alloy;however,an increase in the Al content causes significant decreases in the average grain size and maximum texture intensity of the extruded material owing to an increase in the area fraction of dynamically recrystallized(DRXed)*** Al addition improves the strength of the extruded alloy;this improvement is attributed to the enhanced grain-boundary hardening and solid-solution hardening effects induced by grain refinement and Al solute atoms,*** the Al content increases from 0 wt%to 1 wt%and 2 wt%,the tensile elongation increases substantially from 2.8%to 9.4%and 16.9%,*** reduction in the number and size of un DRXed grains with increasing Al content suppresses the formation and coalescence of cracks in the un DRXed grains during tension,which results in a significant improvement in the tensile ductility of the extruded *** tensile deformation,large undesirable twins that act as crack initiation sites are locally formed in the un DRXed grains of the Mg-3Bi alloy,whereas relatively smaller twins are uniformly formed in both the DRXed and the un DRXed grains of the Mg-3Bi-2Al ***,the extruded Mg-3Bi-2Al alloy has a substantially higher tensile yield strength±elongation product(2924 MPa%)than the extruded Al-free B3 alloy(381 MPa%).

关键词： Mg-Bi-Al alloy Extrusion Microstructure Strength Ductility

Migration routes and differences in migration strategies of Whooper Swans between spring and autumn

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Avian Research 2023年第3期14卷 345-353页

作者： Ji-Yeon Lee hyung-Kyu Nam Jin-Young park Seung-Gu Kang Nyambayar Batbayar Dong-Won Kim jae-Woong Hwang Otgonbayar Tsend Tseveenmyadag Natsagdorj Jugdernamjil Nergui Tuvshintugs Sukhbaatar Wee-Haeng Hur Jeong-Chil Yoo The Korea Institute of Ornithology and Department of Biology Graduate SchoolKyung Hee University26 Kyungheedae-roDongdaemun-guSeoul02447Republic of Korea National Institute of Biological Resources 42 Hwangyeong-roSeo-guIncheon22689Republic of Korea Endangered Species Research Center National Institute of EcologyYeongyang36351Republic of Korea Wildlife Sciences and Conservation Center of Mongolia Union BuildingB-701UNESCO str.Ulaanbaatar14210Mongolia

Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding ***,several species travel slower in spring owing to environmental influences,such as food availability and wind *** trackers were attached to 17 Whooper Swans(Cygnus cygnus) inhabiting northeastern Mongolia,to determine their migration routes and stopover sites in spring and *** between spring and autumn migrations,migration-influencing parameters,and the effect of spring stopover site temperatures were *** swans completed perfect tours between their wintering and breeding sites,and these data were used for *** migration lasted 57 days,with 49.2 days spent at 3.7 stopover *** migration lasted 21.5 days,with 17.5 days spent at 1.0 stopover ***,the swans traveled more rapidly in autumn than in *** distance,number of stopovers,migration speed,and straightness were important migration determinants in both spring and *** distance,stopover duration,number of stopovers,daily travel speed,travel duration,and migration speed differed significantly between spring and *** spring migration,the temperature at the current stopover sites and that at the future stopover sites displayed significant variations(t=1585.8,df=631.6,p <0.001).These findings are critical for the conservation and management of Whooper Swans and their key habitats in East Asian regions,and the data are anticipated to make a particularly significant contribution toward developing detailed management plans for the conservation of their key habitats.

关键词： Key stopover sites Migration characteristics Migration route Migration strategy Tracking Whooper Swan

Relative-Position Estimation Based on Loosely Coupled UWB–IMU Fusion for Wearable IoT Devices

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计算机、材料和连续体（英文） 2023年第4期75卷 1941-1961页

作者： A.S.M.Sharifuzzaman Sagar Taein Kim Soyoung park Hee Seh Lee hyung Seok Kim Sejong University Seoul05006Korea Samsung Advanced Institute of Technology Suwon16678Korea

Relative positioning is one of the important techniques in collaborativerobotics, autonomous vehicles, and virtual/augmented reality (VR/AR)applications. Recently, ultra-wideband (UWB) has been utilized to calculaterelative position as it does not require a line of sight compared to a camerato calculate the range between two objects with centimeter-level ***, the single UWB range measurement cannot provide the relativeposition and attitude of any device in three dimensions (3D) because oflacking bearing information. In this paper, we have proposed a UWB-IMUfusion-based relative position system to provide accurate relative positionand attitude between wearable Internet of Things (IoT) devices in 3D. Weintroduce a distributed Euler angle antenna orientationwhich can be equippedwith the mobile structure to enable relative positioning. Moving average andmin-max removing preprocessing filters are introduced to reduce the standarddeviation. The standard multilateration method is modified to calculate therelative position between mobile structures. We combine UWB and IMUmeasurements in a probabilistic framework that enables users to calculatethe relative position between two nodes with less error. We have carried outdifferent experiments to illustrate the advantages of fusing IMU and UWBranges for relative positioning systems. We have achieved a mean accuracy of0.31m for 3D relative positioning in indoor line of sight conditions.

关键词： Relative position UWB IMU trilateration IoT bayesian filter

EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： LEE Jeung-Hoon JUNG jae-Kwon LEE Kyung-Jun HAN jae-Moon park hyung-Gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent

Long-term radiofrequency electromagnetic fields exposure attenuates cognitive dysfunction in 5×FAD mice by regulating microglial function

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Neural Regeneration Research 2023年第11期18卷 2497-2503页

作者： Yeonghoon Son Hye-Jin park Ye Ji Jeong hyung-Do Choi Nam Kim Hae-June Lee Division of Radiation Biomedical Research Korea Institute of Radiological&Medical SciencesSeoulKorea Department of EMF Research Team Radio and Broadcasting Technology LaboratoryElectronics and Telecommunications Research InstituteDaejonKorea School of Electrical and Computer Engineering Chungbuk National UniversityCheongjuKorea

We have previously found that long-term effects of exposure to radiofrequency electromagnetic fields in 5xFAD mice with severe late-stage Alzheimer’s disease reduced both amyloid-βdeposition and glial activation,including *** examine whether this therapeutic effect is due to the regulation of activated microglia,we analyzed mic roglial gene expression profiles and the existence of microglia in the brain in this study.5xFAD mice at the age of 1.5 months were assigned to sham-and radiofrequency electromagnetic fields-exposed groups and then animals were exposed to 1950 MHz radiofrequency electromagnetic fields at a specific absorption rate of 5 W/kg for 2 hours/day and 5 days/week for 6 *** conducted behavioral tests including the object recognition and Y-maze tests and molecular and histopathological analysis of amyloid precursor protein/a myloid-beta metabolism in brain *** confirmed that radiofrequency electromagnetic field exposure for 6 months ameliorated cognitive impairment and amyloid-β*** expression levels of Iba1(pan-microglial marker)and colony-stimulating factor 1 receptor(CSF1R;regulates microglial prolife ration)in the hippocampus in 5xFAD mice treated with radiofrequency electromagnetic fields were significantly reduced compared with those of the sham-exposed ***,we analyzed the expression levels of genes related to mic rogliosis and microglial function in the radiofrequency electromagnetic fields-exposed group compared to those of a CSF1R inhibitor(PLX3397)-treated *** radiofrequency electromagnetic fields and PLX3397 suppressed the levels of genes related to microgliosis(Csf1r,CD68,and Ccl6)and pro-inflammatory cytokine interleukin-1β.N otably,the expression levels of genes related to mic roglial function,including Trem2,Fcgr1α,Ctss,and Spi1,were decreased after long-term radiofrequency electromagnetic field exposure,which was also observed in response to microglial suppression by *** res

关键词： 5×FAD Alzheimer’s disease CSF1R long term exposure microglial function neuroinflammation radiofrequency electromagnetic fields therapeutic effect

Soil texture affects the conversion factor of electrical conductivity from 1:5 soil-water to saturated paste extracts

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Pedosphere 2022年第6期32卷 905-915页

作者： Bo-Seong SEO Young-jae JEONG Nu-Ri BAEK Hyun-Jin park Hye In YANG Se-In park Woo-Jung CHOI Department of Rural and Bio-systems Engineering(BK21) Chonnam National UniversityGwangju 61186(Republic of Korea) Department of Renewable Resources University of AlbertaEdmontonAlberta T6G 2E3(Canada) Max Planck Institute for Biogeochemistry Jena 07745(Germany) National Institute of Environmental Research Incheon 22689(Republic of Korea) AgriBio Institute of Climate Change Management Chonnam National UniversityGwangju 61186(Republic of Korea)

Electrical conductivity(EC)of soil-water extracts is commonly used to assess soil ***,its conversion to the EC of saturated soil paste extracts(ECe),the standard measure of soil salinity,is currently required for practical *** many regression models can be used to obtain ECe from the EC of soil-water extracts,the application of a site-specific model to different sites is not straightforward due to confounding soil factors such as soil *** study was conducted to develop a universal regression model to estimate a conversion factor(CF)for predicting EC_(e) from EC of soil-water extracts at a 1:5 ratio(EC_(1:5)),by employing a site-specific soil texture(i.e.,sand content).A regression model,CF=8.9105e^(0.0106sand)/1.2984(r^(2)=0.97,P<0.001),was developed based on the results of coastal saline soil surveys(n=173)and laboratory experiments using artificial saline soils with different textures(n=6,sand content=10%-65%)and salinity levels(n=7,salinity=1-24 dS m^(-1)).Model performance was validated using an independent dataset and demonstrated that EC_(e) prediction using the developed model is more suitable for highly saline soils than for low saline *** feasibility of the regression model should be tested at other *** soil factors affecting EC conversion factor also need to be explored to revise and improve the model through further studies.

关键词： coastal saline soils electrical conductivity prediction reclaimed tideland regression model sand content saturation percentage soil salinity

Applications of scaffolds:Tools for enhancing the immunomodulation of mesenchymal stromal cells

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BIOCELL 2022年第6期46卷 1439-1443页

作者： OK-HYEON KIM EUN RAN KIM JUN hyung park HYUN JUNG LEE Department of Anatomy and Cell Biology College of MedicineChung-Ang UniversitySeoul06974South Korea Department of Global Innovative Drugs Graduate School of Chung-Ang UniversitySeoul06974South Korea Severance Biomedical Science Institute Yonsei Biomedical Research InstituteCollege of MedicineYonsei UniversitySeoul03722South Korea

Exogenously delivered mesenchymal stromal cells(MSCs)are therapeutically beneficial owing to their paracrine effect;they secrete various cytokines,nucleic acids,and *** bioengineering techniques can help MSC cultures to release secretomes by providing stem cell niche-like conditions(both structurally and functionally).Various scaffolds mimic the natural extracellular matrix(ECM)using both natural and synthetic polymers,providing favorable environments for MSC proliferation and *** on material properties,either topographically or elastically structured scaffolds can be ***-dimensional scaffolds have tunable substrate rigidities and structures,aiding MSC *** ECM-derived hydrogels are similar to the natural ECM,thus improving the paracrine effects of ***,we discuss recent research on the application of scaffolds to maximize the immunomodulatory function of MSCs.

关键词： Extracellular matrix(ECM) Immunomodulation Mesenchymal stromal cells(MSCs) Scaffolds Stem cell niche