• Journal of the Korea Society for Simulation
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• 제14권3호
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• pp.109-118
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• 2005

The purpose of this paper is to analyze transport ability of AGV(Automated Guided Vehicle) and SHC(SHuttle Carrier). The main difference between two types of transport vehicles is that AGV depends on container crane or transfer crane to do loading/unloading container, but SHC is very independent to it. Therefore, the transport ability of SHC is expected to be higher than AGV. So, in this paper, we established simulation model to evaluate two types of transport vehicles and analyzed the results. Simulation model was established to automated container terminal with perpendicular yard layout, and applied closed loop operation of transport vehicle between apron and stacking yard. In the result, SHC showed very superior than AGV aspect of container crane productivity and vehicle fleets.

• Proceedings of the Membrane Society of Korea Conference
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• 한국막학회 1995년도 제3회 심포지움 (분리막 연구의 최신동향)
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• pp.57-71
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• 1995

A simple mathematical model for gacilitated mass transport with a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation, The concentration fluctuation, developed due to reversible chemical reaction between carrier and solute, could acuse the higher chemical potential gradient and the facilitated transport. For mathematical formulation, an analogy was employed between the mass transfer for the facilitated transport with fixed site carrier membrane and the electron transfer in a parallel resistor-capacitor (RC) circuit. For the single RC model, it was assumed that a single capacitor represented the total carrier and a solute could not inter-diffuse between matrix and carrier, allowing only two diffusional pathways, This assumption was relaxed by adopting a serial combination of the parallel RC circuit. Here, a solute diffuses in two elements (matrix or carrier) can exchange its pathway, exhibiting four diffusional pathways. The current models were examined against experimental data and the agreement was exceptional.

• Journal of environmental and Sanitary engineering
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• 제11권2호
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• pp.21-26
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• 1996

In our previous studies, we reported that lead intoxicated nerve cell by inhibition of the Na$^{+}$-K$^{+}$ ATPase activity and reduction of myo-inositol in nerve cell. As the second series of experiments, in order to understand toxic mechanism of lead for nerve cell, the characteristics of myo-inositol transport system and the effect of lead on its system have been studied in the sciatic nerves of control and lead-treated rats. A lead intoxicated animal model was induced by feeding diet containing lead to Sprague-Dawley rat for two weeks. Four weeks aged Sprague-Dawley rats were divided into three group : normal control group, 10ppm-lead treated group, 100ppm-lead treated group. All rats were sacrified at the end of two weeks. The rate o myo-inositol transport by sciatic nerve isolated from lead-treated rat was significantly decreased compared with that of control rat. This deficit results from that myo-inositol transport system which is carrier mediated and sodium-potassium dependent was inhibited by the lead treatment (both 10ppm and 100ppm) due to increase of the Km value without affecting Vmax value for myo-inositol carrier. These observations suggest that the toxic mechanism of lead on nerve myo-inositol transport system might be a change of affinity without change of maximum transport velocity for carrier.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.391-391
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• 2016

The carrier transport is a key factor that determines the device performances of semiconductor devices such as solar cells and transistors [1]. Particularly, devices composed of in amorphous semiconductors, the transport is often restricted by carrier trapping, associated with various defects. So far, the trapping has been studied for as-grown films at room temperature; however it has not been studied during growth under plasma processing. Here, we demonstrate the detection of trapped carriers in hydrogenated amorphous silicon (a-Si:H) films during plasma processing, and discuss the carrier trapping and defect kinetics. Using an optically pump-probe technique, we detected the trapped carriers (electrons) in an a-Si:H films during growth by a hydrogen diluted silane discharge [2]. A device-grade intrinsic a-Si:H film growing on a glass substrate was illuminated with pump and probe light. The pump induced the photocurrent, whereas the pulsed probe induced an increment in the photocurrent. The photocurrent and its increment were separately measured using a lock-in technique. Because the increment in the photocurrent originates from emission of trapped carriers, and therefore the trapped carrier density was determined from this increment under the assumption of carrier generation and recombination dynamics [2]. We found that the trapped carrier density in device grade intrinsic a-Si:H was the order of 1e17 to 1e18 cm-3. It was highly dependent on the growth conditions, particularly on the growth temperature. At 473K, the trapped carrier density was minimized. Interestingly, the detected trapped carriers were homogeneously distributed in the direction of film growth, and they were decreased once the film growth was terminated by turning off the discharge.

• Journal of Navigation and Port Research
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• 제30권8호
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• pp.691-697
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• 2006

The objective of this study is to develop the alternative model of the container transport vehicle of high productivity for the purpose of the increase of terminal productivity. In order to develop the alternatives, we analyze the technical specification of existing transport vehicles such as YT(Yard Tractor), S/C(Straddle Carrier), SHC(Shuttle Carrier), and AGV(Automated Guided Vehicle) and investigate the operation and performance of transport vehicles to classify the technical generation. The development alternative of transport vehicle presented in this study will usefully be apply to advanced container terminal with higher productivity in near future.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.24-31
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• 1998

The separation and concentration of L-phenylalanine (L-Phe) using a supported liquid membrane (SLM) is investigated. A cation complex agent, di-2-ethylhexyl phosphoric acid (D2EHPA), is used as a carrier in the SLM with n-Heptane as a solvent. The reaction order and equilibrium constant in the formation reaction of L-phe-carrier complex are obtained from the extraction experiment. A mathematical model for a carrier mediated counter transport process is proposed to estimate the diffusion coefficient of L-phe-carrier complexly in the liquid membrant. Permeation experiments of L-phe using a SLM are performed under various operating conditions and optimum conditions for the transport of L-phe are obtained. Concentration of L-phe in the strip phase against its concentration is observed. Transport rate of glucose through liquid membrane is less than that of L-phe in the competitive transport of L-phe and glucose. And the existence of glucose reduced the transport rate of L-phe. The performance of separation with continuous strip phase is increased due to the dilution effect in the strip phase.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2006년도 춘계학술대회 및 창립 30주년 심포지엄(논문집)
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• pp.367-372
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• 2006

The objective of this study is to develop the alternative of the container transport vehicle of new type for the purpose of the increase of terminal productivity. In order to develop the alternatives, we analyze the technical specification of existing transport vehicles such as YT(Yard Trailer), S/C(Straddle Carrier), SHC(Shuttle Carrier), AGV(Automated Guided Vehicle) and investigate the operation and performance of transport vehicles to classify the technical generation. The development alternative of transport vehicle is presented in this study is very useful to advanced container terminal with higher productivity.

• Proceedings of the Korea Society for Simulation Conference
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• 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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• pp.57-63
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• 2005

The purpose of this paper is to analyze transport ability of AGV(Automated Guided Vehicle) and SHC(SHuttle Carrier). The main difference between two types of transport vehicles is that AGV depends on container crane or transfer crane to do loading/unloading container, but SHC is very independent to it. Therefore, the transport ability of SHC is expected to be higher than AGV, So, in this paper, we established simulation model to evaluate two types of transport vehicles and analyzed the results. Simulation model was established to automated container terminal with perpendicular yard layout, and applied closed loop operation of transport vehicle between apron and stacking yard. In the result, SHC showed very superior than AGV aspect of container crane productivity and vehicle fleets,

• Membrane Journal
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• 제27권3호
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• pp.205-215
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• 2017

Polymer membranes are cheap and easy in fabrication, and show a high permeability and selectivity, thus play pivotal roles in gas separation as well as water purification. However, polymer membranes typically exhibit the trade-off relation between permeability and selectivity; i.e. when the permeability is high, the selectivity is low and vice versa. Facilitated transport has been considered one of the solutions to address this issue. Over the last decades, facilitated transport concept had played an important role in preparing the membranes and providing ideal and various models for the transport. Understanding the nature of carrier, the mobility of matrix and the physico-chemical properties of polymer composites are crucial for facilitated transport. Depending on the mobility of carrier, facilitated transport membrane is classified into three; mobile carrier membrane, semi-mobile carrier membrane, fixed-site carrier membrane. Also, there are four types of reversible reaction between the carrier and the specific target; proton transfer reaction, nucleophilic addition reaction, p-complexation reaction and electrochemical reaction. The facilitated transport membranes have been applied in the separation of CO2, O2 and olefin (propylene or ethylene). In this review, major challenges surrounding facilitated transport membranes and the strategies to tackle these challenges are given in detail.

• Proceedings of the Membrane Society of Korea Conference
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• 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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• pp.15-18
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• 1999

A simple mathematical model for facilitated mass transport through a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation. The current model demonstrates that the facilitation factor depends on the extent of concentration fluctuation, the time scale ratios of diffusion to chemical reaction and the ratio of the carrier concentration to the solute solubility in matrix. The model was examined against the experimental data on oxygen transport in membranes containing metallo-porphyrin carriers, and the agreement was exceptional (within 10% error). The basic concept of this approach was applied to separate olefin from olefin/paraffin mixtures. A proprietaty carrier, developed here, resulted that the selectivity of propylene over propane was more than 120 and the propylene permeance exceed 40 gpu.