• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.210-218
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• 2018

In order to generate meshes automatically for finite element analysis of complex structures such as aircraft, a large number of triangular elements are typically created. However, triangular elements are less accurate than rectangular elements, so it is difficult to obtain a reliable solution. This problem can be improved through the meshfree method using the back cell integration. However, this method also causes some problems such as over-use of the integration points and inefficiency of the integral domain. In order to improve these problems, a method of performing integration by setting the integral area based on a node basis has been proposed, but in the case of incompressible material problems, the numerical accuracy deteriorates due to the vibration phenomenon of the solution. Therefore, in this paper, the modified meshfree method is proposed which sets the integral domain as an element domain instead of the nodal domain, and the proposed method improves the numerical instability caused by the conventional meshfree method without decreasing the accuracy regardles of the shape of integral domain. The effectiveness of the modified meshfree method is verified by using 2-D examples.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.490.2-490.2
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• 2014

Since the general solar cells accept sun light at the front side, excluding the electrode area, electrons move from the emitter to the front electrode and start to collect at the grid edge. Thus the edge of gridline can be important for electrical properties of screen-printed silicon solar cells. In this study, the improvement of electrical properties in screen-printed crystalline silicon solar cells by contact treatment of grid edge was investigated. The samples with $60{\Omega}/{\square}$ and $70{\Omega}/{\square}$ emitter were prepared. After front side of samples was deposited by SiNx commercial Ag paste and Al paste were printed at front side and rear side respectively. Each sample was co-fired between $670^{\circ}C$ and $780^{\circ}C$ in the rapid thermal processing (RTP). After the firing process, the cells were dipped in 2.5% hydrofluoric acid (HF) at room temperature for various times under 60 seconds and then rinsed in deionized water. (This is called "contact treatment") After dipping in HF for a certain period, the samples from each firing condition were compared by measurement. Cell performances were measured by Suns-Voc, solar simulator, the transfer length method and a field emission scanning electron microscope. According to HF treatment, once the thin glass layer at the grid edge was etched, the current transport was changed from tunneling via Ag colloids in the glass layer to direct transport via Ag colloids between the Ag bulk and the emitter. Thus, the transfer length as well as the specific contact resistance decreased. For more details a model of the current path was proposed to explain the effect of HF treatment at the edge of the Ag grid. It is expected that HF treatment may help to improve the contact of high sheet-resistance emitter as well as the contact of a high specific contact resistance.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.33-39
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• 2014

One hundred forty four bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in Daejeon area. Among them, one bacterial strain was selected for this study based on its emulsification activity, growth rate and surface tension activity, and this selected bacterial strain was identified as Pseudomonas sp. HN37 through physiological- biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. HN37 utilize the several aliphatic hydrocarbons, 3,5-dinitrosalicylic acid and 2,4-dichlorophooxyacetic acid as a sole carbon source. And this bacterial strain showed a high resistance to antibiotics such as ampicillin and chloramphenicol, as well as heavy metals such as Ba, Cr, Li and Mn. Also, it was found that the optimal pH and temperature for the cell growth, surface tension, and emulsification activity of Pseudomonas sp. HN37 were pH 6.0-9.0 and $30^{\circ}C$, respectively. The emulsification and surface tension activity was reached the maximum to 1% (V/V) crude oil and 1% (W/V) NaCl concentration. The surface tension of the culture broth was decreased from 62 to 27 dyne/cm after fifteen hours of inoculation in LB media.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.133-140
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• 2007

Flash memory has penetrated our life in various forms. For example, flash memory is important storage component of ubiquitous computing or mobile products such as cell phone, MP3 player, PDA, and portable storage kits. Behind of the wide acceptance as memory is many advantages of flash memory: for instances, low power consumption, nonvolatile, stability and portability. In addition to mentioned strengths, the recent development of gigabyte range capacity flash memory makes a careful prediction that the flash memory might replace some of storage area dominated by hard disks. In order to have overwriting function, one block must be erased before overwriting is performed. This difference results in the cost of reading, writing and erasing in flash memory[1][5][6]. Since this difference has not been considered in traditional buffer replacement technologies adopted in system software such as OS and DBMS, a new buffer replacement strategy becomes necessary. In this paper, a new buffer replacement strategy, reflecting difference I/O cost and applicable to flash memory, suggest and compares with other buffer replacement strategies using workloads as Zipfian distribution and real data.

• Journal of Distribution Science
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• v.13 no.10
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• pp.65-72
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• 2015

Purpose - A rapidly changing business environment places great demands on small and medium-sized enterprises (SMEs). These SMEs need to find strategic alternatives for continued growth and, ultimately, survival. Thus, mergers and acquisitions (M&A) are deemed an acceptable solution. Research to date has dealt with M&A in major organizations and focused on post merger integration (PMI). Our study focuses on SMEs, as they are relatively new and unknown to the public. Therefore, this study highlights successful M&A and decision making for SMEs through a case study analysis. Research design, data, and methodology - For this study, we examined an M&A case between company S, which produces cell phone parts, and company P, which produces SSD cases. We reviewed theories and previous studies in M&A literature. We comprehensively examined the decision-making procedure at each M&A stage, describing the situation of the buying company and the selling company from the period of the M&A announcement through deal completion. In addition, we conducted interviews with both companies. The data regarding this case study were collected through interviews with managers of both companies who actively participated in the M&A process. When necessary, we asked them about additional relevant information during the interviews. Results - The result of the M&A between company S and company P was deemed acceptable with the exception of the long negotiation period. However, company S was not able to prepare for PMI after the acquisition due to a controversy over acquisition values. Moreover, the employees of the newly formed company, especially those who came from company P, complained about the M&A and attempted to leave. Thus, implications for successful M&As of SMEs are as follows: First, the procedural compliance of the M&A is needed. Second, support is needed from the CEO for the working group, rather than excessive intervention during due diligence. Third, the right, talented members of the organization should be part of the process of the M&A. Fourth, the use of various types of outside expert or business consultants is needed. Fifth, the strategic intervention by Human Resource managers is required. Last, sharing M&A information among employees is important as information dissemination will help employees be more receptive to such a change. However, this study has several limitations as a single case study; more varied SME M&A case studies are needed in order to generalize the results of the study. Conclusions - Most of the research dealing with M&As has focused on major companies and PMI and neglected SMEs. Thus, our study focuses on SMEs and the decision-making procedures for M&A. This study has significantly contributed to the literature in this area and has provided practical information around the implications of sound decision-making during M&As. Specifically, the results of the study contribute to the need for research on M&A among SMEs, which to date has often been neglected as a topic of choice.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.9-16
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• 1996

In order to understand microbial ecosystem in the fast china sea and Yosu coastal sea horizontal distributions of bacterial flora, Vibrio spp., coliform group, temperature, and salinity in this sea area, were studied 42 sampling stations during 6th-l4th August, 1992. From the results, salinity and temperature were $24.64\~33.78\%_{\circ}$ and $22.53\~29.18^{\circ}C$, respectively. As the open sea far from land goes on, salinity became low while temperature became high. Viable cell counts of bacteral flova, Vibrio spp., and roliform group in Yosu coastal sea water were $1.0\times10^2\~3.0\times10^4/ml,\;0.2\times10\~9.0\times10^3/ml,\;and\;0.3\times10\~3.0\times10^3/ml$ while those of these in the open sea water were $0.4\times10\~2.0\times10^3/ml,\;0.8\times10\~3.0\times10/ml,\;and\;0.9\times10\~1.3\times10/ml$, respectively.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.60-67
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• 2000

Purpose :To evaluate protective mechanism of melatonin against radiation damage and its relationship with apoptosis in mouse jejunum. Materials and Methods: 168 mice were divided into 28 groups according to radiation dose and matatonin treatment. To analysis crypt survival, microcolony survival assay was done according to Withers and Elkind's method. To analysis apoptosis, TUNEL assay was done according to Labet-Moleur's method. Results : Radiation protection effect of melatonin was demonstrated by crypt survival assay and its effect was stronger in high radiation dose area. Apoptosis index with 8 Gy irradiation was 18.4$\%$ in control group and 16.5$\%$ in melatonin treated group. After 18 Gy, apoptosis index was 17.2$\%$ in control group and 15.4$\%$ in melatonin treated group. Apoptosis index did not show statistically significant difference between melatonin treated group and control group. Conclusion : Melatonin shows clear protective effect in mouse jejunum against radiation damage but its protective effect seems not to be related with apoptosis protection effect.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.15-23
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• 1985

Growth response and evapotranspiration of tobacco as to each soil moisture condition treated with different height of ground water table such as 30cm, 100cm, 170cm, and 230cm were investigated. The results obtained were as follows; 1. Soil water potential in the rhizosphere (25cm depth from surface) treated with ground water table (G.W.T) of 230 cm was less than -6.5 bar at 60 days after transplanting. 2. Dry weight of leaves per plant was the highest in the pot treated with 100 cm G.W.T and was the lowest in the pot treated with 230 cm G.W.T.. Leaves/Stem ratio of dry weight was the lowest in the pot treated with 230 cm G.W.T. This would show that extension of leaves as compared with elongation of stem was suppressed. .3. In the roster stress condition of 230 cm G.W.T., extension of leaves was continued until the latter growth stage, Relative growth rate of leaf area per plant of the pot with 30 cm G.W.T. was the highest through all growth period after fixation of G.W.7., but owing to lower density of leaf, the dry weight of leaves per plant was less rather than that of the pot with 170 cm G.W.T. at 64 days after transplanting. 4. The highest evapotranspiration per plant per day was shown at the 45th day after transplanting in the pots with 30cm and 100cm G.W.T. and at 60 days in the pots with 170cm and 230cm G.W.T respectively. 5. In the soil moisture conditions with 30cm and 100cm G.W.T., evapotranspiration per plant per hour was much higher in the daytime that at night as well as in clear day than in rain-cloudy day owing to loner relative humidity , but in the water stress condition with 230 cm G.W.T., that was much lower. 6. Total evapotranspiration per plant during the whole growing period of 64 days was in order of 30cm > 100 cm > 170 cm > 230 cm G.W.T.. Total evapotranspiration for 34 days after fixation of G.W.T was much higher at night than in the daytime in case of water stress conditions i.e 170cm and 230cm G.W.T. but in normal condition of the pots with 30cm and 100cm G.W.T. that was much higher in the daytime than at night. 7. Leaf water potential of the 3rd and 6th leaf from top at 64 days after transplanting was in order of 100cm > 30 cm > 170cm > 230cm G.W.T. The reason why leaf water potential in the pot with 30cm was less than that in the pot with 100cm G.W.T. would be the abnormal turgidity with low density of cell substrates by the excess water absorption in the pot with 30cm G.W.T..

• Toxicological Research
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• v.22 no.4
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• pp.357-364
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• 2006

This study was undertaken to develop a reliable mice model demonstrating similar immunologic phenomena as human atopic dermatitis characterized with predominance of type-2 immune response. BALB/C mice and NC/Nga mice were sensitized twice with $100{\mu}l$ of 1% 2,4-dinitrochlorobenzene (DNCB) or vehicle (acetone : olive oil=4:1 mixture) in a week and challenged twice with $100{\mu}l$ of 0.2% DNCB or the vehicle at the following week. Mice were sacrificed at 19 days following the second DNCB or vehicle challenge for NC/Nga mice and at 28 days following the second DNCB or vehicle challenge for BALB/c mice. Upregulation of plasma 1gE, a hallmark of atopic dermatitis occurrence, was evident in the plasma obtained 4 day after the second DNCB challenge from BALB/c mice (approximately 4-fold) and NC/Nga mice (approximately 6-fold) treated with DNCB in comparison with that of the vehicle treated-control mice, and remain higher $3{\sim}4$ week after the second challenge. Ratio of plasma IgG1 versus IgG2a concentration was significantly higher in the mice treated with DNCB than the control mice, which also implies the skewed type-2 reactivity in vivo. Ratio of interleukin-4 versus interferon gamma produced in the splenic T cell culture supernatants was approximately 3-fold higher in the both strains of mice treated with DNCB than their control mice, respectively. The DNCB-treated mice demonstrated atopic dermatitis-like skin legions characterized with erythma, scaling, and hemorrhage, which was not observed with the control mice. Scratching on face or dorsal area was significantly more frequent (approximately 25-fold) in the DNCB-treated mice than the control at next day of the second DNCB challenge, and scratching frequency remains higher (approximately 4-fold) in the mice treated with DNCB than the control at 14 day following the second DNCB challenge. Overall, the mice model developed through sensitization and challenge with DNCB may be useful for research on atopic dermatitis and development of treatment materials for atopic dermatitis.

• Journal of the Korean Society of Radiology
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• v.3 no.1
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• pp.11-15
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• 2009

In this study, the basic research verifying possibility of applications as radiology image sensor in Digital Radiography was performed, the radiology image sensor was fabricated using a multi-layer technique to decrease dark current. High efficiency materials in substitution for Amorphous Selenium(a-Se) have been studied as a direct method of imaging detector in Digital Radiography to decrease dark current by using PN junction or Hetero junction already used as solar cell, semiconductor. Particle-In -Binder method is used to fabricate radiology image sensor because it has a lot of advantages such as fabrication convenient, high yield, suitability for large area sensor. But high leakage current is one of main problem in Particle-In -Binder method. To make up for the weak points, multi-layer technique is used, and it is considered that high efficient digital radiation sensor can be fabricated with easy and convenient process. In this study, electrical properties such as leakage current, sensitivity, signal linearity is measured to evaluate multi-layer radiation sensor material.