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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

Map-based control method for vehicle stability enhancement

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Journal of Central South University 2015年第1期22卷 114-120页

作者： Moon-Young Yoon Seung-Hwan Baek Kwang-Suk boo heung-Seob Kim Graduate school of Mechanical Engineering Inje University 607 High Safety Vehicle Core Technology Research Center Inje University 607

This work proposes a map-based control method to improve a vehicle's lateral stability, and the performance of the proposed method is compared with that of the conventional model-referenced control method. Model-referenced control uses the sliding mode method to determine the compensated yaw moment; in contrast, the proposed map-based control uses the compensated yaw moment map acquired by vehicle stability analysis. The vehicle stability region is calculated by a topological method based on the trajectory reversal method. A 2-DOF vehicle model and Pacejka's tire model are used to evaluate the proposed map-based control method. The properties of model-referenced control and map-based control are compared under various road conditions and driving inputs. Model-referenced control uses a control input to satisfy the linear reference model, and it generates unnecessary tire lateral forces that may lead to worse performance than an uncontrolled vehicle with step steering input on a road with a low friction coefficient. However, map-based control determines a compensated yaw moment to maintain the vehicle within the stability region,so the typical responses of vehicle enable to converge rapidly. The simulation results with sine and step steering show that map-based control provides better the tracking responsibility and control performance than model-referenced control.

关键词： model-referenced control map-based control vehicle stability yaw moment

Investigation on the magnetomechanical behavior of trilayered GM actuator

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Journal of Rare Earths 2008年第2期26卷 264-267页

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

In this article, it was suggested a TbFe/Co/Dy trilayered GM （Giant Magnetostrictive） film type actuator and investigated the magnetomechanical characteristics of the actuator for micro application. The trilayered films were fabricated at different thickness ratios to get an optimized structure. TbFe had positive GM properties, and cobalt, dysprosium layers made the magnetostriction property of composite film increase in low magnetic field. To fabricate the Si based microactuator with trilayered film, micromachining processes including RIE （Reactive Ion Etching） and selective DC magnetron sputtering techniques were combined. The deposited film thicknesses were measured by X-ray diffraction （XRD）. As a result, the magnetization of the film on the fabricated actuator was observed to characterize the magnetic properties of the TbFe/Co/Dy film using VSM （Vibrating Sample Magnetometer）. The magnetostriction of the actuator was determined by measuring the differences of curvature of the film coated silicon substrates using the optical cantilever method, and the deflections were also estimated under the external magnetic field lower than 0.5T for micro-system applications.

关键词： GM actuator magnetostriction trilayered film magnetron sputtering magnetization rare earths

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

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

Fabrication and characterization of Ag flake hybrid circuits with IPL-sintering

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Journal of Materials Science & Technology 2020年第18期52卷 13-18页

作者： Choong-Jae lee Kwang-Ho Jung Kyung Deuk Min Bum-Geun Park Seung-boo Jung School of Advanced Materials Science Engineering Sungkyunkwan University2066 Seobu-roJangan-guSuwon-si16419Republic of Korea Visual Display Business Samsung Electronics Co.Ltd.129Samsung-roYeongtong-guSuwon-si16677Republic of Korea

The study of photonic sintering has gained interest based on the advantages of fast processing at room ***,printed electronics made from photonic sintering with an intensive pulsed light(IPL)energy source exhibit more mechanical instability than those made from conventional thermal sintering *** solve the mechanical instability problems,we fabricated Ag flake hybrid pastes with a variety of concentrations of Ag flake(0,25,50,75,and 100 wt.%).All of the screen-printed hybrid Ag circuits were fabricated on polyimide substrates and were sintered at 3.5 *** porosity was analyzed using the Brunauer-Emmett-Teller *** IPC(Packaging Electronic Circuits)sliding test was performed to analyze the flexibility of the screen-printed Ag flake hybrid *** adhesion strength of the hybrid circuits was evaluated with a roll-type 90°peel *** hybrid Ag printed circuit showed improvements in both the flexibility and adhesion strength with the addition of Ag flake.

关键词： Low-temperature sintering Flexibility Flaky powders Adhesion strength Intensive pulsed light

Study on the current structure of the thermohaline front in the southeastern entrance of the Yellow Sea during winter

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Acta Oceanologica Sinica 2015年第12期34卷 29-36页

作者： OH Kyung-Hee lee Seok LIE heung-Jae JUNG Kyung Tae QIAO Fangli Korea Institute of Ocean Science and Technology First Institute of Oceanography State Oceanic Administration

A thermohaline front is located at the southeastern entrance of the Yellow Sea in winter, and it is generated by the intrusion of warm saline water into the Yellow Sea caused by a strong northerly wind. Recently, a westward transversal current traveling away from the west coast of Korea toward the open sea area along the front was reported. The westward transversal current is dominant in the surface layer during the temperature inversion period. The formation and structure of this current are examined using a numerical vertical ocean-slice *** two different water masses meet, a front is formed and adjusted geostrophically. In this frontal zone, a horizontal pressure gradient flow by the vertically inclined isopycnal occurs under the thermal wind process in a baroclinic effect, and the cold fresh coastal water moves westward along the front in the upper layer. The barotropic effect across the front and the bottom friction effect strengthen the westward component of the velocity. The velocity of the bottom layer decreases remarkably in the increase of the bottom drag coefficient. This means that the bottom friction with the strong background tidal current causes a reduction in the current in the bottom layer.

关键词： Geostrophic adjustment Southeastern Yellow Sea Thermohaline front Thermal wind Westward transversal current

Behavior of CaO and Calcium in pure Magnesium

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Rare Metals 2006年第z2期25卷 150-154页

作者： HA Seong-Ho lee Jin-Kyu JO Hyung-Ho JUNG Seung-boo KIM Shae K. Department of Advanced Material Engineering Sungkyunkwan University 300 Chunchun-dong Jangan-gu Suwon Gyunggi-do 440-746 KoreaAdvanced Material Division Korea Institute of Industrial Technology 7-47 Songdo-dong Yeonsu-gu Incheon 406-840 Korea Advanced Material Division Korea Institute of Industrial Technology 7-47 Songdo-dong Yeonsu-gu Incheon 406-840 Korea Department of Advanced Material Engineering Sungkyunkwan University 300 Chunchun-dong Jangan-gu Suwon Gyunggi-do 440-746 Korea

Mg alloys exhibit a number of good properties such as low density, good castability and high specific strength. However, molten Mg and Mg alloys are ignited without the melt protective gases during melting and casting process due to their high reactivity. The purpose of this study is to investigate effects of Ca and CaO on pure Mg through microstructure observation, ignition test and phase analysis. With increasing Ca and CaO contents, the ignition resistance of Ca or CaO added pure Mg is increased and the grains are refined. As results of XRD and EDS, CaO is reduced to Ca in CaO added pure Mg. Mg2Ca phase is formed even in 0.1 wt.%CaO added pure Mg by reduction mechanism, while Mg2Ca phase is formed over 1.35 wt.% Ca added pure Mg.

关键词： Mg CaO ignition resistance Mg2Ca phase

Indian monsoon variability in the Mahanadi Basin over the last two glacial cycles and its implications on the Indonesian throughflow

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Geoscience Frontiers 2023年第1期14卷 215-229页

作者： Jongmin lee Sunghan Kim Minoru Ikehara Keiji Horikawa Yoshihiro Asahara Chan Min Yoo boo-Keun Khim Department of Oceanography Pusan National UniversityBusan 46241South Korea Deep-sea Mineral Resources Research Center Korea Institute of Ocean Science&TechnologyBusan 49111South Korea Division of Glacial Environment Research Korea Polar Research InstituteIncheon 21990South Korea Center for Advanced Marine Research Kochi UniversityKochi 783-8502Japan Graduate School of Science and Engineering for Research University of ToyamaToyama 930-8555Japan Department of Earth and Planetary Sciences Nagoya UniversityNagoya 464-8601Japan

The orbital-scale variability of the Indian summer monsoon(ISM)has been influenced by multiple factors,such as atmospheric CO_(2)concentration,global ice volume,and *** for weathering activity and paleo-productivity provide potential insights into the driving forces of its *** documented multi-proxy data at IODP Site U1445,located in the Mahanadi Basin of the northwestern Bay of Bengal,to find out ISM variability over the last 200 *** proxy records,such as Nd/Sr isotopes of detrital particles,clay mineral compositions of the fine-grained sediments,biogenic opal and CaCO_(3),organic carbon contents,and carbon isotopes of organic matter,represent sediment sources,weathering patterns,and paleo-productivity related to the ISM *** Nd/Sr isotope data and clay mineral compositions suggest that the sediments at Site U1445 originated mainly from the Ganges,Brahmaputra,and Meghna rivers without dramatic provenance change between the glacial and interglacial *** weathering activity inferred from clay mineral compositions and the paleo-productivity shift reconstructed by biogenic opal and CaCO_(3)contents suggest that the land-sea interactions were closely linked to the ISM precipitation between the glacial and interglacial *** precipitation by the strong ISM resulted in intense chemical weathering and dominant biogenic opal deposition during the interglacial *** contrast,low precipitation by the weak ISM led to reduced chemical weathering and predominant CaCO_(3)deposition during the glacial ***,the ISM variability driving the land-sea interactions in the Mahanadi Basin was modulated by the Indonesian throughflow(ITF).Our study emphasizes the role of low-latitude forcing of climatic changes in the strong relationship between the ISM and ITF over orbital periods,providing a base for future investigations.

关键词： Provenance Weathering activity Paleo-productivity Indian summer monsoon Bay of Bengal Indonesian throughflow