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Magnetostrictive Flexible Thin Film Structure for Micro Devices

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Journal of Rare Earths 2007年第S1期25卷 182-185页

作者： heung-shik lee Chongdu Cho Department of Mechanical Engineering Inha University Yonghyun-dong Nam-kuIncheon 402-751 South Korea

Polyimide (Kapton, Dupont Corp.) based magnetostrictive thin film structures were designed and fabricated for micro device applications. In particular the growth of films on flexible substrates was studied to allow a simple integration of the system in miniaturized magnetostrictive devices. The films were fabricated on different substrates to compare their different magnetic and structural properties. It showed much more magnetostriction and higher impact resistance results compared with traditional Si based film type actuators. In the fabrication process, amorphous TbDyFe films with thicknesses of 500 nm, 1 μm, 1.5 μm respectively, were deposited on the designed substrate by DC magnetron sputtering. During sputtering process the substrate holder was maintained at room temperature. After the sputter process, X-ray diffraction studies were also carried out to determine the film structure and thickness of the sputtered film. At last, magnetization from VSM (Vibrating Sample Magnetometer) and magnetostriction from optical cantilever method of each structure were measured to estimate the magneto-mechanical characteristics under the external magnetic field lower than 0.7 T for micro-system applications.

关键词： magnetostrictive thin film micro device flexible polyimide substrate rare earths

The Study on Effect of Exhaust Performance According to Active Muffler Valve Spring as Followed Spring Constant

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Journal of Thermal Science 2002年第4期11卷 372-377页

作者： Seuk Cheun Choi Tae Woo Kong Han shik Chung Hyo Min Jeong Young heung Chun Graduate School of Mechanical and Precision Engineering Gyeongsang National UniversityInpyeongdong 445 Tongyong Kyongnam 650-160Korea School of Transport Vehicle Engineering Gyeongsang National UniversityThe Institute of Marine IndustryInpyeongdong 445 Tongyong Kyongnam 650-160Korea

This study represents the influence on exhaust performance by active muffler valve *** main experimental parameters were engine speeds and torsion coil spring constants in the active *** the muffler valve spring has a low spring constant of k=0.75,the sound pressure level was low at the region of engine speed 2000 to 2500 r/min,and the velocity of exhaust gas was high at spring constant k=*** the engine speed was under 1500 r/min,the mean concentration of CO was high in case without muffler *** the engine speed in the range of 1600 to 2600 r/min with spring constant k=0.75,the mean HC concentration showed the lowest *** muffler valve,the temperature in the muffler was higher than the case with muffler *** research represented that the performance of the active muffler valve spring constant k=0.75 was higher than that without muffler valve and valve spring constant k=*** the three cases of experimental condition,with a spring constant k=0.75,0.70 and without muffler valve,the exhaust performance was high in case active muffler valve spring constant k=0.70.

关键词： active muffler torsion coil spring spring constant sound pressure level

Milk protein-shelled gold nanoparticles with gastrointestinally active absorption for aurotherapy to brain tumor

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Bioactive Materials 2022年第2期7卷 35-48页

作者： Hyung shik Kim Seung Jae lee Dong Yun lee Department of Bioengineering College of Engineeringand BK FOUR Biopharmaceutical Innovation Leader for Education and Research GroupHanyang UniversitySeoul04763Republic of Korea Institute of Nano Science and Technology Hanyang UniversitySeoul04763Republic of Korea

Orally absorbable gold nanoparticles(AuNP)having cancer ablation therapy is strongly demanded to treat glioblastoma multiforme(GBM)for patients with its highest incidence ***,we develop a milk protein lactoferrin-conjugated AuNP for its oral absorption and targeting to the GBM through the interaction between lactoferrin(Lf)and lactoferrin receptor(LfR)that is highly expressed in the intestine,blood-brain barrier and *** stability and long circulation of AuNP,glutathione and polyethylene glycol(PEG)is introduced,which is called to *** Lf-PEG-AuNP are orally administered to orthotopic GBM-bearing mice,11-fold and 8-fold higher concentrations of AuNP are measured in bloodstreams and GBM in the brain,respectively,compared with ***,orally administered Lf-PEG-AuNP exhibit an outstanding temperature rise in GBM by irradiating laser and significantly reduce tumor ***,we suggest that the Lf-PEG-AuNP can fundamentally target GBM in the brain through oral absorption,and that its efficient photothermal therapy is possible.

关键词： intestine absorption gastrointestinal

Adsorption and photocatalytic degradation of bisphenol A using TiO2 and its separation by submerged hollowfiber ultrafiltration membrane

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Journal of Environmental Sciences 2006年第1期18卷 193-200页

作者： Jae-Wook lee Tae-Ouk Kwon Ramesh Thiruvenkatachari Il-shik Moon Department of Chemistry Engineer Seonam University Namwon 590-711 Korea Department of Chemistry Engineer Sunchon National University Suncheon 540-742 Korea

This study evaluates the adsorption ability ofbisphenol A（BPA） on titanium dioxide（TiO2） and its effect on the photocatalysis by advanced oxidation process using UV radiation and TiO2 photocatalyst. Degradation of BPA was also evaluated for the system without adsorption prior to photocatalytic reaction. The separation of TiO2 from BPA solution treated by pilot-scale photocatalytic reactor （capacity 0.16 m^3） was studied using submerged ultrafiltration （UF） membrane. It was found that although adsorption capacity of BPA was not high, adsorption played an important role in improving the efficiency ofphotocatalysis. On the other hand, during the separation of TiO2 particles from aqueous suspension, the permeate flux of the membrane was strongly affected by transmembrane pressure and TiO2 dose. The permeate turbidity was decreased below 1 NTU.

关键词： bisphenol A TiO2 adsorption membrane photocatalysis

Assessment criteria for nonverbal interaction contents in r-learning

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Journal of Central South University 2013年第9期20卷 2388-2398页

作者： CHOI Jong-hong lee Jong-yun YOON heung-seob Department of Computer Education Chungbuk National University Department of English Education Chungbuk National University

r-learning,which is based on e-learning and u-learning,is defined as a learning support system that intelligent robots serve verbal and nonverbal interactions on ubiquitous computing *** order to guarantee the advantages of r-learning contents with no limits of timc and place and with nonverbal interaction which are not in e-learning contents,in recent years,assessment criteria for r-learning contents are urgently ***,the reliable and valid assessment criteria were developed for nonverbal interaction contents in r-learning,and its detailed research content is as ***,assessment criteria for nonverbal interaction in r-learning contents will be specified into gesture,facial expression,semi-verbal message,distance,physical contact and ***,the validity of the developed assessment criteria will be proved by ***,the assessment criteria for nonverbal interaction contents will be helpful when choosing the better r-learning content and producing the better r-learning content,and the reliability of school education is improved ultimately.

关键词： r-learning, r-learning contents assessment criteria nonverbal interaction contents confirmatory factor analysis construct validity

Synergetic analysis of springtime air pollution episodes over Gwangju,Korea

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Journal of Environmental Sciences 2017年第7期29卷 270-283页

作者： Sung-Kyun Shin Kwon-Ho lee Seung-shik Park Man Sing Wong Research Institute for Radiation-Satellite(RIRS) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Atmospheric and Environmental Sciences(DAES) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Environment and Energy Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Land Surveying and Geo-Informatics The Hong Kong Polytech UniversityKowloonHong Kong

The characteristics of springtime aerosols,including their optical and microphysical properties,were analyzed for the months of March to May of 2009 in Gwangju（35.23°N,126.84°E）,Korea.A high Light Detection and Ranging（LIDAR）-derived aerosol depolarization ratio（δ） of 0.25 ± 0.04 was determined on dust particles during the observation ***？ngstr？m exponent values of the 440–870 nm wavelength pair（？_（440–870）） and single-scattering albedo at 675 nm（Ω_（675）） measured by a CIMEL sun/sky radiometer were 0.77 ± 0.19 and 0.95 ±0.01,*** elevated dust layers reached a maximum elevation of 4 km above sea ***/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size（？_（440–870） ranged between1.33 and 1.36） and higher light-absorbing（Ω_（675） of 0.92 ± 0.01） *** aerosols are mostly distributed at altitudes 〈 1.2 *** root-mean-square deviation（RMSD） between the aerosol optical depth（AOD,τ） derived from LIDAR_（（τ_（LIDAR））） and from the CIMEL sun/sky radiometer_（（τ_（CIMEL））） varied with respect to the surface PM10 *** RMSD between τ_（LIDAR） and τ_（CIMEL） was as low as 13% under lower PM_（10） concentration levels（〈 100 μg/m^3）.In contrast,the RMSD between τ_（LIDAR） and τ_（CIMEL） increased three times（~31%） under high surface PM_（10） concentration levels（〉100 μg/m^3）.These results suggest that the accuracy of τ_（LIDAR） is influenced by specific atmospheric conditions,regardless of its uncertainty.

关键词： LIDAR Sun/sky radiometer MODIS Optical/microphysical properties Aerosol optical depth

Massively parallel electro-optic sampling of space-encoded optical pulses for ultrafast multi-dimensional imaging

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Light(Science & Applications) 2023年第2期12卷 304-313页

作者： Yongjin Na Hyunsoo Kwak Changmin Ahn Seung Eon lee Woojin lee Chu-shik Kang Jungchul lee Junho Suh Hongki Yoo Jungwon Kim Korea Advanced Institute of Science and Technology(KAIST) Daejeon 34141Korea Korea Research Institute of Standards and Science(KRISS) Daejeon 34113Korea

High-speed and high-resolution imaging of surface profiles is critical for the investigation of various structures and mechanical dynamics of micro-and nano-scale *** particular,recent emergence of various nonlinear,transient and complex mechanical dynamics,such as anharmonic vibrations in mechanical resonators,has necessitated real-time surface deformation imaging with higher axial and lateral resolutions,speed,and dynamic ***,real-time capturing of fast and complex mechanical dynamics has been challenging,and direct time-domain imaging of displacements and mechanical motions has been a missing element in studying full-field structural and dynamic ***,by exploiting the electro-optic sampling with a frequency comb,we demonstrate a line-scan time-of-flight(TOF)camera that can simultaneously measure the TOF changes of more than 1000 spatial coordinates with hundreds megapixels/s pixel-rate and sub-nanometre axial resolution over several millimetres *** unique combination of performances enables fast and precise imaging of both complex structures and dynamics in three-dimensional devices and mechanical resonators.

关键词： deformation dimensional dynamics

Efficient photovoltaic effect in graphene/h-BN/silicon heterostructure self-powered photodetector

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Nano Research 2021年第6期14卷 1967-1972页

作者： Ui Yeon Won Boo heung lee Young Rae Kim Won Tae Kang Ilmin lee Ji Eun Kim Young Hee lee Woo Jong Yu Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwon16419Republic of Korea Center for Integrated Nanostructure Physics Institute for Basic Science(IBS)Suwon16419Republic of Korea

Graphene(Gr)/Si-based optoelectronic devices have attracted a lot of academic attention due to the simpler fabrication processes,low costs,and higher performance of their two-dimensional(2D)/three-dimensional(3D)hybrid interfaces in Schottky junction that promotes electron-hole ***,due to the built-in potential of Gr/Si as a photodetector,the Iph/Idark ratio is often hindered near zero-bias at relatively low illumination *** is a major drawback in self-powered *** this study,we have demonstrated a self-powered van der Waals heterostructure photodetector in the visible range using a Gr/hexagonal boron nitride(h-BN)/Si structure and clarified that the thin h-BN insertion can engineer asymmetric carrier transport and avoid interlayer coupling at the *** dark current was able to be suppressed by inserting an h-BN insulator layer,while maintaining the photocurrent with minimal decrease at near *** a result,the normalized photocurrent-to-dark ratio(NPDR)is improved more than 104 ***,both Iph/Idark ratio and detectivity,increase by more than 104 times at−0.03 V drain *** proposed Gr/h-BN/Si heterostructure is able to contribute to the introduction of next-generation photodetectors and photovoltaic devices based on graphene or silicon.

关键词： graphene hexagonal boron nitride van der Waals heterostructure self-powered Research

Removal of heavy metals using waste eggshell

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Journal of Environmental Sciences 2007年第12期19卷 1436-1441页

作者： PARK heung Jai JEONG Seong Wook YANG Jae Kyu KIM Boo Gil lee Seung Mok School of Environmental Science and Engineering Inje University 621-749607GyungnamKorea. Department of Environmental Engineering Kwangwoon University SeoulKorea Division of Architecture and Civil Engineering Dong-seo University BusanKorea Department of Environment and Disaster Prevention Kwandong University GangneungKorea

The removal capacity of toxic heavy metals by the reused eggshell was studied. As a pretreatment process for the preparation of reused material from waste eggshell, calcination was performed in the furnace at 800℃ for 2 h after crushing the dried waste eggshell. Calcination behavior, qualitative and quantitative elemental information, mineral type and surface characteristics before and after calcination of eggshell were examined by thermal gravimetric analysis （TGA）, X-ray fluorescence （XRF）, X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. After calcination, the major inorganic composition was identified as Ca （lime, 99.63%） and K, P and Sr were identified as minor components. When calcined eggshell was applied in the treatment of synthetic wastewater containing heavy metals, a complete removal of Cd as well as above 99% removal of Cr was observed after 10 rain. Although the natural eggshell had some removal capacity of Cd and Cr, a complete removal was not accomplished even after 60 rain due to quite slower removal rate. However, in contrast to Cd and Cr, an efficient removal of Pb was observed with the natural eggshell rather than the calcined eggshell. From the application of the calcined eggshell in the treatment of real electroplating wastewater, the calcined eggshell showed a promising removal capacity of heavy metal ions as well as had a good neutralization capacity in the treatment of strong acidic wastewater.

关键词： wasted eggshell CaO removal heavy metals