• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.236-239
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• 1998

This research was performed to check the transport characteristics of heavy metals in contaminated soil, that is, the influence of humic acid and phosphate on transport characteristics of heavy metals was studied. From the results of column mode experiments about heavy metal behavior, the order time to reach breakthrough and equilibrium was soil ＋ humic acid( 20g ) > soil ＋ humic acid ( 5 g ) > soil without Humic acid addition > soil+humic acid( 50g ). It is because the dissolved organic carbon content increased as the soil organic matter content increased. As the phosphate increased, so did the time to reach breakthrough and equilibrium. The order of time was soil + phosphate( 50 mg ) > soil + phosphate( 20 mg ) > soil . phosphate( 10 mg ) > soil without phosphate addition. It is because the phosphate ion worked as alkalinity donor and the calcium ion co-injected worked as the accelerator of coprecipitation of heavy metals.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.393-396
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• 2005

The reactive transport model on the biologically mediated sequential nitrate transformation and its subsequent transport was developed and tested. This model was coded as a reaction module within the RT3D framework (Clement, 1997). Transports of the reasonable six mobile solutes (dissolved organic carbon, $O_2,\;{NO_3}^-,\;{NO_2}^-,\;N_2O,\;N_2$) and two immobile microbes were simulated. The simulation results gave a reasonable match with supposed transport pattern. For the next step, the developed model will be validated against experimental data.

• Journal of Magnetics
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• v.7 no.3
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• pp.98-100
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• 2002

Tunnel magnetoresistive devices using an individual multi-walled carbon nanotube were fabricated and their low-temperature electrical transport propertiers were investigated. With the ferromagnetic Co electrodes, the multi-walled carbon nanotube exhibited hysteretic magnetoresistance curve at low temperatures. Depending on the temperature and the bias current, the magnetoresistance ratio can be as high as 16% at the temperature of 2.2 K. Such high magnetoresistance ratio indicates a long diffusion length of the multi-walled carbon nanotube.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.615-617
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• 2003

Carbon monoxide (CO) is one of the important trace gases because its concentration in the troposphere directly influences the concentrations of tropospheric hydroxyl (OH), which controls the lifetimes of tropospheric trace gases. CO traces the transport of global and regional pollutants from industrial activities and large scale biomass burning. The distributions of CO were analyzed using the MOPITT data for East Asia, which were compared with the ozone distributions. In general, seasonal CO variations are characterized by a peak in the spring, which decrease in the summer. The monthly average for CO shows a similar profile to that for O$_3$. This fact clearly indicates that the high concentration of CO in the spring is possibly due to one of two causes: the photochemical production of CO in the troposphere, or the transport of the CO into East Asia. The seasonal cycles for CO and O$_3$ in East Asia are extensively influenced by the seasonal exchanges of different air mass types due to the Asian monsoon. The continental air masses contain high concentrations of O$_3$ and CO, due to the higher continental background concentrations, and sometimes to the contribution from regional pollution. In summer this transport pattern is reversed, where the Pacific marine air masses that prevail over Korea bring low concentrations of CO and O$_3$, which tend to give the apparent summer minimums.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.422-431
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• 2017

The biogeochemical information of riverine organic matter gives a detailed and integrated recording of natural and anthropogenic activity within a watershed. To investigate the changes in quality and quantity of organic carbon transporting from mountain to ocean via river channels, we estimated the concentrations of dissolved (DOC) and particulate organic carbon (POC), and then traced the source origin of POC using stable carbon isotopes ratio before and after summer rainfalls in the Tamjin River and Ganjin Bay, Korea. Along the small watershed, a total of 13 sites including headwaters, dam reservoir, river and estuary were established for the study. We found some interesting findings in the aspect of distribution of DOC/POC concentration changing their origin sources dynamically flowing downstream. In particular, the river channel transport downstream mainly DOC to river mouth, although upper dam reservoir increased POC concentration by phytoplankton production in summer. Whereas, in the river mouth and estuary, POC was dominated not only by local supply from nearby reed saltmarsh, but also by marine phytoplankton production, respectively. The findings can contribute to increasing the understanding of riverine organic carbon transport in upper large dam and lower open estuary system.

• Carbon letters
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• v.28
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• pp.60-65
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• 2018

Linear carbon chains (LCCs) encapsulated inside the hollow cores of carbon nanotubes (CNTs) have been experimentally synthesized and structurally characterized by Raman spectroscopy and transmission electron microscopy. However, in terms of electronic conductivity, their transportation mechanism has not been investigated theoretically or experimentally. In this study, the density of states and quantum conductance spectra were simulated through density functional theory combined with the non-equilibrium Green function method. The encapsulated LCCs inside (5,5), (6,4), and (9,0) single-walled carbon nanotubes (SWCNTs) exhibited a drastic change from metallic to semiconducting or from semiconducting to metallic due to the strong charge transfer between them. On the other hand, the electronic change in the conductance value of LCCs encapsulated inside the (7,4) SWCNT were in good agreement with the superposition of the individual SWCNTs and the isolated LCCs owing to the weak charge transfer.

• Membrane Journal
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• v.25 no.3
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• pp.248-255
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• 2015

Aminated polyetherimide membrane synthesized in the laboratory according to amine ratio was used for measurement of gas permeability, diffusivity, and solubility about carbon dioxide, nitrogen, methane, oxygen, and sulfur dioxide with Time-lag method at room temperature. Generally, gas permeability is totally decreased because the more amination rate reacted to the main chain of amine groups, the more intermolecular space became narrow. However, gas permeability of sulfur dioxide was increased due to combination of sulfur dioxide and amine groups have acid and base properties respectively. Diffusivity and solubility of dry gas are totally decreased excluding sulfur dioxide as increasing amination rate. In case of sulfur dioxide, however, diffusivity as well as solubility was increased as increasing amination rate. Selectivity of carbon dioxide/nitrogen showed 60 when amination rate was 3. In case of humid gas, gas permeability of carbon dioxide was 70 barrer when relative humidity showed 100, and selectivity with nitrogen approximately showed 18.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.60-67
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• 2021

Recently, research attention has been focused on vibration-free vehicles to transport small numbers of expensive electronic products. Vibration-free vehicles can be used to transport expensive test equipment or semiconductors, mainly produced in the domestic IT industry, and can serve as a readily available transportation system for short driving distances due to the increased efficiency on narrow national highways. This study was aimed at developing a Z-Spring to minimize the vibration by installing an air spring instead of the plate spring applied to conventional freight cars and to prevent the damage of the loaded cargo from the shock occurring during movement. The mechanical properties (elastic modulus, tensile strength, and shear strength) of carbon fiber (CF) and glass fiber (GF) prepreg were derived, and ANSYS ACP PrepPost analyses were performed. It was observed that in the case of hybrid composites, the total deformation and equivalent stress are higher than that of CFRP; however, in terms of the unit cost, the hybrid Z-Spring is more inexpensive and durable compared to the GF.

• Biomedical Science Letters
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• v.11 no.4
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• pp.487-492
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• 2005

The baculovirus/insect cell expression system is of great value in the study of structure-function relationships in mammalian glucose-transport proteins by site-directed mutagenesis and for the large-scale production of these proteins for mechanistic and biochemical studies. Spodoptera frugiperda Clone 21 (Sf2l) cells grow well on TC-100 medium that contains $0.1\%$ D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, very little is known about the properties of the endogenous sugar transporter(s) in Sf2l cells, although a saturable transport system for hexose uptake has been previously revealed in the Sf cells. In order to further examine the substrate and inhibitor recognition properties of the Sf2l cell transporter, the ability of hexoses to inhibit 2-deoxy-D-glucose (2dGlc) transport was investigated by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. Transport was effectively inhibited by D-mannose and D-glucose. Of the hexoses tested, L-glucose had the least effect on 2dGlc transport in the Sf2l cells, indicating that the transport is stereoselective. Unlike the human HepG2 type glucose transport system, D-mannose had a somewhat greater affinity for the Sf2l cell transporter than D-glucose, implying that the hydroxyl group at the C-2 position is not necessary for strong binding. However, epimerization at the C-4 position of D-glucose (D-galactose) resulted in a dramatic decrease in affinity of the hexose for the Sf2l cell transporter. Such a lowering of affinity might be the result of the involvement of the C-4 hydroxyl in hydrogen bonding. It is therefore suggested that Sf2l cells were found to contain an endogenous sugar transport activity that in several aspects resembles the human HepG2 type glucose transporter, although the insect and human transporters do differ in their affinity for cytochalasin B.

• Membrane Journal
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• v.31 no.3
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• pp.212-218
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• 2021

It is inevitable to generate incomplete combustion gases when mankind utilizes fossil fuels. From this point of view, gas separation process of combustion gas suggests the possibility of recycling CO gas. In this study, we fabricated a facilitated transport polymeric composite membrane for CO separation using AgBF₄ and HBF₄. The copolymer was synthesized via free-radical polymerization of poly(vinyl alcohol) (PVA) as a main chain and acrylic acid (AA) monomer as a side chain. The polymer synthesis was confirmed by FT-IR and the interactions of graft copolymer with AgBF₄, and HBF₄ were characterized by TEM. PVA-g-PAA graft copolymer membranes showed good channels for facilitated CO transport. In this perspective, we suggest the novel approach in CO separation membrane area via combination of grafting and facilitated transport.