• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.9
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• pp.687-697
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• 2006

The air and water flow distribution are experimentally studied for a heat exchanger composed of round headers and 10 flat tubes. The effects of tube protrusion depth as well as mass flux, and quality are investigated, and the results are compared with the previous 30 channel results. The flow at the header inlet is annular. For the downward flow configuration, the water flow distribution is significantly affected by the tube protrusion depth. For flush-mounted geometry, significant portion of the water flows through frontal part of the header. As the protrusion depth increases, more water is forced to the rear part of the header. The effect of mass flux or quality is qualitatively the same as that of the protrusion depth. Increase of the mass flux or quality forces the water to rear part of the header. For the upward flow configuration, different from the downward configuration, significant portion of the water flows through the rear part of the header. The effect of the protrusion depth is the same as that of the downward flow. As the protrusion depth increases, more water is forced to the rear part of the header. However, the effect of mass flux or quality is opposite to the downward flow case. As the mass flux or quality increases, more water flows through the frontal part of the header. Compared with the previous thirty channel configuration, the present ten channel configuration yields better flow distribution. Possible explanation is provided from the flow visualization results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1338-1342
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• 2011

In this paper, threshold voltage characteristics have been analyzed as one of short channel effects occurred in double gate(DG)MOSFET to be next-generation devices. The Gaussian function to be nearly experimental distribution has been used as carrier distribution to solve Poisson's equation, and threshold voltage has been investigated according to projected range and standard projected deviation, variables of Gaussian function. The analytical potential distribution model has been derived from Poisson's equation, and threshold voltage has been obtained from this model. Since threshold voltage has been defined as gate voltage when surface potential is twice of Fermi potential, threshold voltage has been derived from analytical model of surface potential. Those results of this potential model are compared with those of numerical simulation to verify this model. As a result, since potential model presented in this paper is good agreement with numerical model, the threshold voltage characteristics have been considered according to the doping profile of DGMOSFET.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.101-104
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• 2006

Water management is considered to be one of the main issues to be addressed for the performance improvement of proton exchange membrane (PEM) fuel cell. For good water management, the detailed information on the water distribution inside an operating PEM fuel cell should be available to main an adequate level of hydration in the PEM While avoiding performance decline due to liquid rater flooding. For the PEM fuel cell to be commercially viable as vehicle applications, the flooding on the cathode side should be minimized during the fuel ceil operation. In this study to investigate cathode flooding and its relation with temperature distribution in flow channels, visualization study was performed on the cathode side of a PEM fuel cell. For the direct visualization of temperature field and water transport in cathode flow channels, a transparent cell was designed and manufactured using quartz window. Water transport and its two-phase flow characteristics in flow channels were investigated experimentally. Also, the visualization of temperature distribution In cathode flow channels was made by using IR camera. Results indicated that the temperature rise near the exit of cathode flow channel was found. It is found that this area corresponds to the flooding area from both temperature and flooding visualization results It is expected that this study can effectively contribute to get the detailed data on water transport linked with heat management during the operation of a PEM fuel cell

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.11
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• pp.881-887
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• 2014

This paper presents numerical study on flow and heat transfer characteristics in micro-gap plate heat exchanger. In particular, we investigate the effect of flow inertia on the flow distribution from single main channel to multiple parallel micro-gaps. The flow regime of the main channel is varied from laminar regime (Reynolds number of 100) to turbulent regime (Reynolds number of 10000) by changing the flow rate, and non-uniformity of the flow distribution and temperature field is evaluated quantitatively based on the standard deviation. The flow distribution is found to be significantly affected by not only the header design but also the flow rate of the main channel. It is also observed that the non-uniformity of the temperature field has its maximum at the intermediate flow regime.

• The Journal of Fisheries Business Administration
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• v.12 no.2
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• pp.61-71
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• 1981

This essay examines the marketing of Fishermen's Cooperative in Korea, and in particular considers the marketing channel of fisheries products, No company can perform by itself all the activities involved in the production and distribution of its products and services to its final markets. It must work with other firm to get the job done. Thus marketing channel firms of the fisheries products include primarily the Fishermen's Cooperative the licensed dealers and tile merchant middlemen, The goal of marketing is in matching of segments of supply and demand. Every producer seeks to the link the marketing channel firms that will help it accomplish its objective best. Therefore this study surveys the three types of marketing channels through tile central market That. is, they are a marketing channel through the terminal market, a marketing channel through the fishermen's cooperative terminal market, and a marketing channel through the private fish market. Consequently the Fishermen's Cooperative can choose to improve in any of tile marketing channel as follows: \circled1 The Fishermen's Cooperative is nominated wholesaler in the terminal market. \circled2 It is abolished to sell by double auction in the production district terminal market and the consuming city terminal market of Fishermen's Coopertive. \circled3 The steady wholesalers in private fish market are entitled to the licensed dealers. \circled4 The Fishermen's Cooperative sponsored voluntary chains join with retailer, supermarkets, consumers' society. Therefore the study of marketing channel of fisheries products can appropriately referred to satisfying needs and wants through exchange process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.77-78
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• 2009

We report numerical simulations to investigate of the dependence of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of 10um, but varying the channel width W from 5nm to 5um, and thickness t from 10nm to 30nm. We have shown that $Q_{ON}/Q_{OFF}$ drastically decreases (from ${\sim}2.9{\times}10^4$ to ${\sim}9.8{\times}10^3$) as the channel thickness increases (from 10nm to 30nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed than that in the bottom of control channel.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.1-7
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• 2013

In the next generation of mobile communication systems, high data rates and high capacity will be possible if multiple antennas are used at new frequencies. This paper presents the correlations between channel parameter path loss (PL), delay spread (DS), angular spread (AS) and K-factor established based on channel measurements. To avoid interference from Korean DTV broadcasting, we measured the channel characteristics in urban/rural/suburban areas on Jeju Island using a channel sounder and $4{\times}4$ antennas. The correlations between channel parameter show that the wireless channel characteristics can be determined and effective communication system design can be produced for use in similar environments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.728-731
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• 2009

We report numerical simulations to investigate of the dependendce of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of $10\;{\mu}m$, but varying the channel width W from 5 nm to $5\;{\mu}m$, and thickness t from 10 nm to 30 nm. We have show that $Q_{ON}/Q_{OFF}$ drastically decreases (from $^{\sim}2.9{\times}10^4$ to $^{\sim}9.8{\times}10^3$) as the channel thickness increases (from 10 nm to 30 nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed then in the bottom of control channel.

• Asia Marketing Journal
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• v.16 no.2
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• pp.15-38
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• 2014

This paper explores the influence of pursuing goals on customer channel preference in Chinese rural market. With the rapid change in distribution channels and increase in multi-channels, it is necessary to understand the preference for channel choice as well as product choice. This study empirically validated the conceptual framework of the relationship between the pursuing goals and customer channel choice proposed by Balasubramanian, Raghunathan, and Mahajan (2005). Based on the survey data of 232 fertilizer customers in Chinese rural market, this study explores how economic, social, and psychological pursuing goals can impact customer channel preference by mediating variables of product utility and process utility. The results indicate that pursuing goals positively related with product utility and process utility, and product / process utility can mediate the relationship between pursuing goals and customer channel preference positively. Consequently, we can conclude that customers' economic-social-psychological pursuing goals can directly influence customer channel preference via their purchase process utility and product utility. This result also implies that product utility is effective on process utility during consumer's buying decision making, and process utility and product utility are not mutually independent. Therefore, purchase process utility is a "latent driving force" on customer's channel choice decision.

• Journal of Distribution Research
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• v.15 no.2
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• pp.35-70
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• 2010

In this study, we examined distribution channel relationship by using the idea of Cheong, which is a unique feeling an positive role in Korean society. Companies make great efforts to maintain long-term relationship with buyers. Understanding distinctive relationship system of each culture should precede these efforts to bring effective results. So we considered how Cheong, a meaningful factor in Korean distribution channel, affects relationship quality and performance. As a result of research analysis from 272 survey questionnaires of retailers, engaging in Crops Protected Material industry in Korea, supplier's idiosyncratic investment, retailer's Cheong, and dependence of retailers on suppliers have positive effects on relationship quality. Supplier's idiosyncratic investment and cognitive factors have the highest influence and Cheong, an emotional factor, follows. Dependence, a motivational factor has the least influence. We confirmed that retailer's cooperation and long-term orientation are directly influenced by retailer's commitment. Active cooperation of the retailer, a partner of a distribution channel, is regarded as an essential factor for supplier's effective business. Retailer's commitment increased that cooperation. Retailer's trust and commitment also decreased relationship conflicts. The results of this study imply that companies should increase idiosyncratic investment to improve relationship quality. But increasing idiosyncratic investment is limited because it requires monetary investment. Therefore companies need to recognize the importance of Cheong, revealed as a new factor, improving relationship quality and to make the best use of it. In this study, we contributed theoretically by examining the role of Cheong, and introducing its distribution discipline. We also make practical suggestions about supplier's relationship management.