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Effect of Root-Induced Chemical Changes on Dynamics and Plant Uptake of Heavy Metals in Rhizosphere soils

Pedosphere 2010年第4期20卷 494-504页

作者： k.R.kim G.OWENs R.NAIDU Climate Change & Agroecology Division Department of Agricultural EnvironmentNational Academy of Agricultural Science Centre for Environmental Risk Assessment and Remediation University of South Australia Cooperative Research Centre for Contamination Assessment and Remediation of the Environment

It is increasingly recognized that metal bioavailability is a better indicator of the potential for phytoremediation than the total metal concentration in soils; therefore, an understanding of the influence of phytoremediation plants on metal dynamics at the soil-root interface is increasingly vital for the successful implementation of this remediation technique. In this study, we investigated the heavy metal and soil solution chemical changes at field moisture, after growth of either Indian mustard （Brassica juncea） or sunflower （Helianthus annuus L.）, in long-term contaminated soils and the subsequent metal uptake by the selected plants. In addition, the fractions of free metal ions in soil solution were determined using the Donnan membrane technique. After plant growth soil solution pH increased by 0.2-1.4 units and dissolved organic carbon （DOC） increased by 1-99 mg L^-1 in all soils examined. soluble Cd and Zn decreased after Indian mustard growth in all soils examined, and this was attributed to increases in soil solution pH （by 0.9 units） after plant growth. Concentrations of soluble Cu and Pb decreased in acidic soils but increased in alkaline soils. This discrepancy was likely due to a competitive effect between plant-induced pH and DOC changes on the magnitude of metal solubility. The fractions of free Cd and Zn ranged from 7.2% to 32% and 6.4% to 73%, respectively, and they generally decreased as pH and DOC increased after plant growth. Metal uptake by plants was dependant on the soil solution metal concentration, which was governed by changes in pH and DOC induced by plant exudates, rather than on the total metal concentrations. Although plant uptake also varied with metal and soil types, overall soluble metal concentrations in the rhizosphere were mainly influenced by root-induced changes in pH and DOC which subsequently affected the metal uptake by plants.

关键词： bioavailability phytoremediation speciation

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Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water

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Journal of Environmental sciences 2009年第1期21卷 23-29页

作者： Veeriah Jegatheesan seung Hyun kim C. k. Joo GAO Baoyu school of Engineering James Cook University Townsville QLD 4811 Australia. Department of Civil Engineering Kyungnam University 631-701 Masan Korea Chilseo Water Treatment Plant Haman 637-940 Korea school of Environmental science and Engineering Shandong University Jinan 250100 China

In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chllseo Water Treatment Plant （CWTP） situated in Haman, korea as well as the effluents from sand and granular activated carbon （GAC） filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting （FRA and sRA） organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and sRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and sRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products （DBPs）. If DBPs are assumed to form due to the interactions between chlorine and sRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

关键词： chlorine decay model initial concentration nitrogenous compounds organic and inorganic compounds reaction rate constants

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Nanodendrites of platinum-group metals for electrocatalytic applications

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Nano Research 2018年第12期11卷 6111-6140页

作者： Nitin k.Chaudhari Jinwhan Joo Hyuk-bu kwon Byeongyoon kim Ho Young kim sang Hoon Joo kwangyeol Lee Department of Chemistry Korea UniversitySeou102841Republic of Korea Research Institute of Natural sciences (RINs) Korea UniversitySeou102841Republic of Korea school of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST)Ulsan44919Republic of Korea

Developing highly efficient and durable catalysts for future electrochemical and energy applications is one of the main subjects of current studies in renewable energy generation. In the past several years, researchers have developed Pt-based alloy electrocatalyst nanomaterials that exhibit promising electrocatalytic properties for various electrochemical applications. The efficient structural and morphological control of Pt-based alloy materials plays a decisive role in achieving these enhanced electrocatalytic properties. The present review article emphasizes the recent progress and important developments in the synthesis and electrocatalytic applications of Pt-group-based nanodendrite materials. The following review will help the exploration and development of better catalysts for practical applications and aims to elucidate the nanodendrite structure of Pt-group metals.

关键词： nanodendrites platinum-group metals electrochemical and energy conversion nanostructure

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Xenos peckii vision inspires an ultrathin digital camera

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Light(science & Applications) 2018年第1期7卷 272-278页

作者： Dongmin keum kyung-Won Jang Daniel s.Jeon Charles s.H.Hwang Elke k.Buschbeck Min H.kim ki-Hun Jeong Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Korea school of Computing Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Korea Department of Biological sciences University of CincinnatiCincinnatiOH 45221-0006USA

Increased demand for compact devices leads to rapid development of miniaturized digital ***,conventional camera modules contain multiple lenses along the optical axis to compensate for optical aberrations that introduce technical challenges in reducing the total thickness of the camera ***,we report an ultrathin digital camera inspired by the vision principle of Xenos peckii,an endoparasite of paper *** male Xenos peckii has an unusual visual system that exhibits distinct benefits for high resolution and high sensitivity,unlike the compound eyes found in most insects and some *** biologically inspired camera features a sandwiched configuration of concave microprisms,microlenses,and pinhole arrays on a flat image *** camera shows a field-of-view(FOV)of 68 degrees with a diameter of 3.4mm and a total track length of *** biologically inspired camera offers a new opportunity for developing ultrathin cameras in medical,industrial,and military fields.

关键词： camera sandwich digital

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Effects of corner modifications on wind loads and local pressures on walls of tall buildings

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Building simulation 2021年第4期14卷 1109-1126页

作者： k.T.Tse Gang Hu Jie song Hyo seon Park Bubryur kim Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina school of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen518055China Engineering Research Center of Urban Disasters Prevention and Fire Rescue Technology of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China Department of Architectural Engineering Yonsei UniversitySeoul120-749R.O.Korea Department of Architectural Engineering Kyungil UniversityGyeongbukR.O.Korea

In this study, the aerodynamic characteristics of tall buildings with corner modifications (e.g., local wind force coefficients, mean pressure distributions, normalized power spectrum density, and extreme local pressure) were examined. Wind tunnel experiments were conducted to measure the wind pressures on building models with different heights and recessed corners of different ratios. At a wind direction of a = 0° (i.e., wind blowing on the front of a building), corner modifications effectively reduced wind forces in all cases. specifically, small corner modification ratios reduced wind forces more effectively than their larger counterparts. However, corner modifications resulted in extreme local pressure on building surfaces. In addition, for small corner modification ratios, the probability of extreme local pressure occurring at a = 0° was high. This probability was also high for large corner modification ratios at a = 15° (i.e., wind blowing slightly obliquely on the front of a building) because wind blowing obliquely creates substantial vortex shedding on one side surface and extreme negative pressure over one building side surface. Results of computational fluid dynamic modeling were adopted to determine details of the aerodynamic characteristics of tall buildings with corner modifications.

关键词： tall building aerodynamic modification local pressure extreme local wind loads proper orthogonal decomposition computational fluid dynamics

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Breakup of the Neoarchean supercontinent kenorland:Evidence from zircon and baddeleyite U-Pb ages of LIP-related mafic dykes in the Coorg Block,southern India

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Geoscience Frontiers 2024年第4期15卷 97-114页

作者： Cheng-Xue Yang M.santosh Jarred Lloyd stijn Glorie Y.Anilkumar k.s.Anoop Pin Gao sung-Won kim school of Earth sciences and Resources China University of Geosciences BeijingBeijing 100083PR China Institute of Earth sciences China University of Geosciences BeijingBeijing 100083PR China Department of Earth sciences University of AdelaideAdelaide SAAustralia Department of Geology University of KeralaKariavattomTrivandrumIndia Geology Division Korea Institute of Geoscience and Mineral ResourcesDaejeon 34132Republic of Korea

The Coorg Block in southern Peninsular India is one of the oldest crustal blocks on Earth that preserves the evidence for continental crust formation during the Paleo-Mesoarchean through subductionrelated arc magmatism,followed by granulite facies metamorphism in the *** this study,we report for the first time,the'bar codes'of a major Paleoproterozoic Large Igneous Province in the Coorg Block through the finding of mafic dyke *** gabbroic dykes from the Coorg Block,dom-inantly composed of plagioclase-pyroxene assemblage,show a restricted range in siO_(2)values of 50.04-51.27 wt.%,and exhibit a sub-alkaline tholeiitic *** rocks show relatively flat LREE and constant HREE patterns and lack obvious Eu *** element modeling suggests that the dyke swarm was fed from a melt that originated at a shallow mantle level in the spinel stability *** grains are rare in the gabbro samples and those separated from two samples yielded 207Pb/206Pb weighted mean dates of 2214±12 Ma and 2221±7 *** grains show magmatic features with depleted LREE and enriched HREE and positive Ce and negative Eu *** grains were dated from five gabbro samples which yielded 207Pb/206Pb weighted mean ages ranging between 2217±7 Ma and 2228±10 *** combined data show a clear age peak at ca.2.2 *** mafic dykes in the Coorg Block show geochemical similarities with ca.2.2 Ga mafic dyke swarms in different regions of the Dharwar and other cratons in Peninsular India and elsewhere on the *** data also support the inference that the global mafic magmatism at ca.2.2 Ga was linked with intracontinental rifting of the Archean cratons through mantle upwelling or plume *** correlate the mafic dyke swarms in the Coorg Block with attempted rifting of the Neoarchean supercontinent kenorland.

关键词： Mafic dyke swarm Paleoproterozoic Large Igneous Province Geochronology Continental rifting Neoarchean supercontinent

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High Temperature Mechanical Properties of Ni-Al-Cr Based Alloys for Advanced Die-Materials Applications

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Journal of Materials science & Technology 2008年第3期24卷 305-308页

作者： W.Y.kim H.s.kim Y.G.Yoo I.D.Yeo Advanced Materials R&D Division Korea Institute of Industrial Technology7-47Songdo-dongYeonsu-gu

In this study, we report on advanced Ni3Al based high temperature structural alloys with Zr and B addition in order to apply in the fields of die-casting and high temperature press forming as die materials. Microstructures and mechanical properties of Ni3Al based intermetallic alloys produced by vacuum arc melting were investigated in terms of phase analysis by using a scanning electron microscope （sEM） equipped with an X-ray energy dispersive spectrometer （EDs）, an X-ray diffractometer （XRD） and tensile test. The duplex microstructural feature consisting of γ＇ matrix phase and small intermetallic dispersoids was observed to be distributed over the whole microstructure. The ultimate tensile strength of the present alloy was superior to commercial iron-based and Ni-based die-materials especially in the high temperature region.

关键词： Intermetallic Die material Alloying effect Mechanical property

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Effects of Mo and Zr on Microstructure,Mechanical Properties and Wear Resistance of Fe-Al Based Alloys

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Journal of Materials science & Technology 2008年第3期24卷 309-312页

作者： I.D.Yeo H.s.kim Y.G.Yoo W.Y.kim Advanced Materials R&D Division Korea Institute of Industrial Technology7-47Songdo-dongYeonsu-gu

In this work the microstructure, mechanical properties and wear resistance of Fe-Al based alloys with various alloying elements were studied. The microstructures were examined by optical and scanning electron microscopy （sEM） equipped with an energy dispersive X-ray spectroscope （EDs）. Two types of alloys were prepared by vacuum arc melting. One is Fe-28Al based alloys （D03 structured） with and without alloying elements such as Mo and Zr. The other one is Fe-35Al based alloys （B2 structured） produced with the same manner. For both types of alloys, Mo addition had found to exhibit an equiaxed microstructure, while dendritic structure was observed to show the effect of Zr addition. These microstructural features were more evinced with increasing content of alloying element. Concerning the mechanical properties and wear resistance, Fe-35Al based alloys were superior to Fe-28Al based alloys over the whole temperature range investigated.

关键词： Fe-Al alloy Intermetallic Mechanical properties Wear resistance

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Optimization study of the Efficient spindle

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Journal of Thermal science 2008年第3期17卷 243-246页

作者： Y.D.kim D.H.Chun M.s.kang H.D.kim korea Textile Machinery Research Institute school of Textiles Yeungnam University school of Mechanical Engineering Andong National University

In the field of yarn dyeing, the most generally employed method is a type of package dyeing which uses a package of cheese stacked on a spindle made of a perforated tube. spindles up to now, have been designed without considering the characteristics of dyeing liquid, focusing only on the geometric configuration which cause many problems such as lack of level dyeing. To improve the level dyeing and find the appropriate spindle configuration for the most effective dyeing process, this study examines the spindle flow-field in detail, using a computational method. Flow characteristics inside the spindle have been investigated with varying in porosity, porous diameter and the velocity of the flow. The results show that the total pressure of the flow through the spindle is used to overcome body force. The characteristics of the flow from the porous spindle could also be observed. Based on the results from this study, an effective spindle configuration for level-dyeing has been proposed.

关键词： Porosity spindle Yarn Dyeing Computational Fluid Dynamics

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Interaction of streamwise and Wall-Normal Velocities in Combined Wave-Current Motion

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China Ocean Engineering 2005年第4期19卷 557-570页

作者： In-soo kim Daniel s.kOH Young-Chae sONG Division of Construction and Environmental Engineering College of EngineeringKorea Maritime University Busan606791Korea

The aim of this paper is to present an analytical expression for the streamwise velocity distribution in a non-uniform flow in the presence of waves; the correlation between the horizontal and vertical velocity components has been compreheusively examined. Different from previous researches which attributed the deviation of velocity from the classical log-law to the wave Reynolds stress, i.e. - ρ uv^- only, this study demonstrates that the momentum flux caused by mean velocities, i.e., u^- and v^-, is also responsible for the velocity deviation, and it is found that the streamwise velocity for a flow in the presence of non-zero wall-normal velocity does not follow the classical log-law, but the modified log-law proposed in this study based on simplified mixing-length theorem. The validity of the modified log-law has been verified by use of available experimental data from published sources for combined wave-current flows, and good agreement between the predicted and observed velocity profiles has been achieved.

关键词： streamwise velocity distribution wave-current flow Reynolds shear stress non-zero wall-normal velocity

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