• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.89-100
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• 2006

In order to estimate delivered nutrients load from non-point sources in the Gap stream watershed in Daejeon, a distributed watershed model SWAT2000 was used so that it could predict the impact of land management practices on water, sediments and chemicals yields in large complex watersheds with varing soils, land uses and management condition over long period of time. The SWAT2000 was applied to the Daejeon (Indong), Yudeung (Boksu) and Gap (Hoeduck) streams for TMDL (Total Maximum Daily Load) of nutrients. The observed water quality and streamflow data of the year of 2002 and 2003 were used for calibration, and those of the year 2004 and 2005 were used for validation. Simulated results were evaluated by Estimation Efficiency Analysis (COE), Regression Analysis $(R^2)$ and Relative Error (R.E.) for the nutrients amounts on the monthly and yearly basis by comparing observed load with estimated load obtained by using SWAT2000 simulations. The COE value fur T-N was ranged from 0.59 to 0.78, $R^2$ values for T-N ranged from 0.65 to 0.84, and R.E values fur T-N load ranged from 4% to 20%. COE value far T-N was ranged from 0.59 to 0.73, $R^2$ values for T-P ranged from 0.67 to 0.82, and R.E values for T-P load ranged from 3% to 25%. Estimated results of SWAT2000 simulation for 3 sites (Indong, Boksu, Hoedeok) were reasonably satisfactory. This study indicated that SWAT2000 model could be applicable to estimate the nutrients load from the Gap stream watershed in Korea.

• Transactions of Materials Processing
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• v.29 no.3
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• pp.157-162
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• 2020

Blind rivet nuts are increasingly used in automotive for the joining of sheets. Their application, however, requires appropriate design guides to prevent catastrophic events arising from the failure of joints. In this study, the shaft shape of a frequently used M8 blind rivet nut is optimized based on 3D numerical analysis of the blind rivet nut considering the characteristics of thread. The thread needs to be modeled to suitably consider the fastening of the M8 bolt after the crimping process. FE analysis showed that while the friction in the contact between crimp flange and plate has no significant effect on the crimp geometry, shaft thickness (t) and shaft height (h) are the most significant design variables. The parameter study including various combinations of t and h reveals that they affect the gap (the distance between the crimped flange and the plate that develops through riveting) and the load acting on the plate. The gap is an indicator of the tightening force. It is found that t is inversely proportional to the gap, and proportional to the load, whereas h is proportional to the gap and inversely proportional to the load. Based on our FE analysis results, we propose the range 0.062 < t/h < 0.1 to ensure sufficient fastening (high clamping load, small gap) of the M8 blind rivet nut. The design guide for determining the t/h ratio proposed in this study can be used for general quantitative analysis of the size and the t/h ratio of blind rivet nuts.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.224-231
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• 2003

The aim of this study was to investigate the effect of resveratrol on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes. Anti-oxidative activity of resveratrol was measured by $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl assay and dichlorodihydrofluorescein diacetate oxidation assay. Gap junctional intercellular communication in HaCaT keratinocytes was assessed using the scrape loading/dye transfer technique. Western blots and reverse transcription-polymerase chain reaction were also analyzed for connexin 43 protein and mRNA expression, respectively. Resveratrol scavenged directly the stable $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl radical over a concentration range of 4 mg/ml ($78.2{\pm}2.7$% of control) to 500 mg/ml ($29.9{\pm}4.2$% of control) and decreased the intracellular reactive oxygen species induced by ultraviolet A (UVA) irradiation ($89.3{\pm}1.1$% of UVA group), ultraviolet B (UVB) irradiation ($70.9{\pm}1.7$% of UVB group) and 12-0-tet-radecanoylphorbol-13-acetate (TPA, $48.3{\pm}1.1$% of TPA group), respectively. UVA irradiation and TPA markedly reduced gap junctional intercellular communication, which was restored by resveratrol. There were no significant differences in the level of connexin 43 protein and mRNA expression among any of the experimental groups. Our data suggests that resveratrol has the protective effect on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes, and this protection is likely due to the scavenging of reactive oxygen species.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.3
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• pp.81-88
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• 2002

The root joint in the welding structures are apt to failure by the stress concentration which is occurred by the external force. Therefore, in the safety and reliability of structure, the complete penetration joint welding which are obtained by the groove welding with edge preparation is generally required. Nevertheless, fillet T-joint welding without edge preparation is often carried out in the fields to reduce working time and consumption of welding electrode, however, this process is likely to produce inadequate joint penetration such as root gap. In this paper, the focus of research is to investigate distribution of welding residual stresses in the plate(or flange) and web of T-joint weld, and especially in the near of root gap notch that is due to incomplete joint penetration. For the analysis, we have chosen model of T-joint weld in the cases of single and multi-pass welding with submerged arc welding and analyzed model by using finite element programs considering the heat conduction and thermal elasto-plastic theory.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.4
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• pp.402-406
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• 1988

The MgGa2Se4 single crystal for study of optical properties is for the first time grown by Bridgmna method. The crystal structure of grown MgGa2Se4 single crystal has the Rhomobohedral structure (R3m) and its lattice constant are a=3.950\ulcorner c=38.893\ulcornerin Hexagonal structure. The energy band structure of grown MgGa2Se4 single crystal structure has direct band gap and the optical energy gap measured from optical absorption in this crystal is 2.20eV at 290K. The temperature dependence of energy gap was given Eg(T)=Eg(O)-aT\ulcorner)B+T), from varshni equation, where Eg(O)=2.34eV, a=8.79x10**-4eV/and b=250K.

• The Hankook-Saengyark Bo
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• no.267
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• pp.1-8
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• 2007

2007년도 협회 중점사업/9개 품목 123농가에 GAP 인증품 출하 허용/GAP인증 한약재 공급협약 체결/올 상반기 시호.지황 등 600t 수입/기자수첩/지회장회의 이모저모/약용작물 특성에 맞는 APC 시설 및 안전성 검사기준 필요/식품의약품안전청, GACP지침 초안 마련/GAP인증약재 판로개척 위해 '동분서주'/'국산한약재 고품질화 및 경쟁력 제고방안' 세미나/"토종약초 사러 함양으로 오세요"/중국약용작물 GAP 산지 및 약재시장 시찰(상)/국산한약재-소매시세표

• Mycobiology
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• v.49 no.5
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• pp.469-475
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• 2021

Three strains, YP416^T, YP421^T, and Y422, were isolated from soil samples in Pocheon City, Gyeonggi province, South Korea. The strains belong to two novel yeast species in the genus Mrakia. Molecular phylogenetic analysis showed that the strain YP416^T was closely related to Mrakia niccombsii. Still, it differed by 9 nucleotide substitutions with no gap (1.51%) in the D1/D2 domain of the LSU rRNA gene and 14 nucleotide substitutions with 7 gaps (2.36%) in the ITS region. The strain YP421^T differed from the type strain of the most closely related species, Mrakia aquatica, by 5 nucleotide substitutions with no gap (0.81%) in the D1/D2 domain of the LSU rRNA gene and 9 nucleotide substitutions with one gap (1.43%) in the ITS region. The names Mrakia terrae sp. nov. and Mrakia soli sp. nov. are proposed, with type strains YP416^T (KCTC 27886^T) and YP421^T (KCTC 27890^T), respectively. MycoBank numbers of the strains YP416^T and YP421^T are MB 836844 and MB 836847, respectively.

• The Korean Journal of Applied Statistics
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• v.32 no.3
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• pp.331-348
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• 2019

Understanding the tumor heterogeneity due to differences in the growth pattern of metastatic tumors and rate of change is important for understanding the sensitivity of tumor cells to drugs and finding appropriate therapies. It is often possible to test for differences in population means using t-test or ANOVA when the group of N samples is distinct. However, these statistical methods can not be used unless the groups are distinguished as the data covered in this paper. Statistical methods have been studied to test heterogeneity between samples. The minimum combination t-test method is one of them. In this paper, we propose a maximum combinatorial t-test method that takes into account combinations that bisect data at different ratios. Also we propose a method based on the idea that examining the heterogeneity of a sample is equivalent to testing whether the number of optimal clusters is one in the cluster analysis. We verified that the proposed methods, maximum combination t-test method and gap statistic, have better type-I error and power than the previously proposed method based on simulation study and obtained the results through real data analysis.

• Journal of Korean Academy of Nursing
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• v.31 no.5
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• pp.871-884
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• 2001

this study was to investigate the perception gap on nursing service between consumers and providers. Method: the questionnaire founded on the SERVQUAL was developed and distributed to 300 patients and 210 nurses at the three subjected general hospitals in three provincial city, Korea during February to March, 2001. For data analysis, Cronbachs' Alpha, frequency, t-test, and paired t-test were used. Result: 1. In the gap analysis on the 20 properties constituting nursing service, providers almost all perceived higher than consumer in quality. Among them, the number of properties being statistically significant was 7 in the expectation, 18 in the important and 7 in the performance. 2. In the comparison analysis of the perception gap on the expectation-performance and the important-performance, it turned out that the subjected hospitals had to improve their equipment and facilities immediately. It was suggested a good strategy to strengthen the responsiveness factor and the assurance factor of nursing service. Conclusion: it could be concluded that nurses have to recognize the blind spot of their perception and endeavor to take away the perception gap between consumers and providers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.254-261
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• 2006

The effect of enhanced geometry (pore diameter, gap width) is investigated on the pool boiling of R-123/oil mixture for the enhanced tubes having pores with connecting gaps. Tubes with different pore diameters (and corresponding gap widths) are specially made. Significant heat transfer degradation by oil is observed for the present enhanced tubes. At 5% oil concentration, the degradation is 26 to 49% for $T_{sat}=4.4^{\circ}C$. The degradation increases 50 to 67% for $T_{sat}=26.7^{\circ}C$. The heat transfer degradation is significant even with small amount of oil (20 to 38% degradation at 1% oil concentration for $T_{sat}=4.4^{\circ}C$), probably due to the accumulation of oil in sub-tunnels. The pore size (or gap width) has a significant effect on the heat transfer degradation. The maximum degradation is observed for $d_p$ = 0.20 mm tube at $T_{sat}=4.4^{\circ}C$, and for $d_p$=0.23 mm tube at $T_{sat}=26.7^{\circ}C$. The minimum degradation is observed for $d_p$=0.27 mm tube for both saturation temperatures. It appears that the oil removal is facilitated for the larger pore diameter (along with larger gap) tube. The highest heat transfer coefficient with oil is obtained for $d_p$ =0.23 mm tube, which yielded the highest heat transfer coefficient for pure R-123. The heat transfer degradation increases as the heat flux decreases.