• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.2
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• pp.51-55
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• 2015

The present research is focused on the effect of porous graphite what is influenced on the 4H-SiC crystal growth by PVT method. We expect that it produces more C-rich and a change of temperature gradient for polytype stability of 4H-SiC crystal as adding the porous graphite in the growth cell. The SiC seeds and high purity SiC source materials were placed on opposite side in a sealed graphite crucible which was surrounded by graphite insulator. The growth temperature was around $2100{\sim}2300^{\circ}C$ and the growth pressure was 10~30 Torr of an argon pressure with 5~15 % nitrogen. 2 inch $4^{\circ}$ off-axis 4H-SiC with C-face (000-1) was used as a seed material. The porous graphite plate was inserted on SiC powder source to produce a more C-rich for polytype stability of 4H-SiC crystal and uniform radial temperature gradient. While in case of the conventional crucible, various polytypes such as 6H-, 15R-SiC were observed on SiC wafers, only 4H-SiC polytype was observed on SiC wafers prepared in porous graphite inserted crucible. The defect level such as MP and EP density of SiC crystal grown in the conventional crucible was observed to be higher than that of porous graphite inserted crucible. The better crystal quality of SiC grown using porous graphite plate was also confirmed by rocking curve measurement and Raman spectra analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.129-136
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• 2018

The estimation of the fatigue design life for large welded structures is usually performed using the liner cumulative damage method such as Palmgren-Miner rule or the equivalent damage method. When a fatigue crack is detected in a welded steel structure, the residual service life has to be estimated base on S-N curve method and liner elastic fracture mechanics. In this study, to examine the 3D fatigue crack behavior and estimate the fatigue life of out-of-plane gusset fillet welded joint, the fatigue tests were carried out on the model specimens. Investigations of three-dimensional fatigue crack propagation on gusset welded joint was used the finite element analysis of FEMAP with NX NASTRAN and FRANC3D. Fatigue crack growth analysis was carried out to demonstrate the effects of aspect ratio, initial crack length and stress ratio on out-of-plane gusset welded joints. In addition, the crack behaviors of fatigue tests were compared with those of the 3D crack propagation analysis in terms of changes in crack length and aspect ratio. From this analysis result, SIFs behaviors and crack propagation rate of gusset welded joint were shown to be similar fatigue test results and the fatigue life can also be predicted.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.569-574
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• 2015

Arthrospira platensis has high lipid and pigment (such as chlorophyll and carotenoid) contents and thus evaluated as an important resource in functional food production. The cell growth rate and pigment concentration of EM24 increased by approximately 1.2-fold than those of the wild-type strain (WT). Fluorescence intensity levels in EM24, which were quantified with a lipid triolein standard curve, also increased by approximately 1.5-fold than those in WT (62.9 mg/Lvs. 38.9 mg/L). The analysis of fatty acid profiles indicated that the gamma-linoleic acid level in EM24 increased by 1.5-fold than that in WT.

• Natural Product Sciences
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• v.23 no.2
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• pp.125-131
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• 2017

Clitoria ternatea or Commonly known blue pea, is a perennial climber crop native to Asian countries. The current study was aimed to evaluate the antimicrobial activity C. ternatea extract on food borne microorganisms and its antifungal effect on Penicillium expansum. The extract showed significant antimicrobial activity against 3 Gram positive bacteria, 2 Gram negative bacteria and 1 filamentous fungus on disc diffusion assay. The extract also showed good biocidal effect on all Gram positive bacteria tested and P. expansum. However, the kill curve analysis revealed that the fungicidal activity of the extract against P. expansum conidia was depend on the concentration of the extract and the time of exposure of the conidia to the extract. The scanning electron micrograph of the extract treated P. expansum culture showed alterations in the morphology of fungal hyphae. The germination of P. expansum conidia was completely inhibited and conidial development was totally suppressed by the extract, suggesting the possible mode of action of anthocyanin. Besides, the extract also exhibited 5.0-log suppression of microbial growth relative to control in the rice model. The results indicate the potential use of the C. ternatea anthocyanin as food biopreservative.

• Journal of Mushroom
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• v.14 no.4
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• pp.244-248
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• 2016

In order to isolate thermophilic bacteria with high activity of CMCase and xylanase, spent mushroom substrates was collected from an oyster mushroom cultivation farm in Jinju, Gyeongnam, Korea. Among the isolates, one strain designated as YJ09 was selected by agar diffusion method. The isolate YJ09 was identified as a member of Bacillus licheniformis based on biochemical characteristics using Bacillus ID kit and MicroLog system. Comparative 16S rDNA sequence analysis showed that isolate YJ09 formed a distinct phylogenetic tree within the genus Bacillus and was most closely related to Bacillus licheniformis with sequence similarity of 98.9%. Based on its physiological properties, biochemical characteristics and phylogenetic distinctiveness, the isolate YJ09 was classified as Bacillus licheniformis. The CMCase and xylanase activity of B. licheniformis YJ09 was slightly increased corresponding to the bacterial population from exponential phase to stationary phase in the growth curve of B. licheniformis YJ09.

• Environmental Engineering Research
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• v.22 no.4
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• pp.407-416
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• 2017

$CO_2$ emission is increasingly focused by public. Beijing and Tianjin are conceived to be a new economic point of growth in China. However, both of them are suffering serious environmental stress. In order to seek for the effect of socioeconomic factors on the $CO_2$ emission of this region, a novel methodology -symbolic regression- is adopted to investigate the relationship between $CO_2$ emission and influential factors of Beijing and Tianjin. Based on this method, $CO_2$ emission models of Beijing and Tianjin are built respectively. The models results manifested that Beijing and Tianjin own different $CO_2$ emission indicators. The RMSE of models in Beijing and Tianjin are 255.39 and 603.99, respectively. Further analysis on indicators and forecast trend shows that $CO_2$ emission of Beijing expresses an inverted-U shaped curve, whilst Tianjin owns a monotonically increasing trend. From analytical results, it could be argued that the diversity rooted in different development orientation and the mixture of different natural and industrial environment. This research further expands the investigation on $CO_2$ emission of Beijing and Tianjin region, and can be used for reference in the study of carbon emissions in similar regions. Based on the investigation, several policy suggestions are presented.

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.299-304
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• 1974

The physical status (standing height, body weight, chest girth, sitting height, length of leg, length of thigh, thigh girth, length of crus, length of arm, brachial length, antebrachial girth and skinfold thickness) of 360 healthy middle and high school boys aged between 12 and 17 years in Taegu area was measured and evaluated by means of dispersion. For regression equation and coefficient ofidetermination of each status against standing height were computed. The growth progress of physical status had a tendency to be exponential and, generally, between 13 and 14 years of age the fastest progress was observed. The regression coefficient of body weight against standing height (0.90) was largest and that of skinfold thickness against standing height (0.09) was smallest. In general, the dimension of the regression coefficient was accordant with the dimension of respective physical status. Except in length of thigh and skinfold thickness, coefficient of determination of each physical status against standing height was almost 1 and the regression line could express the relation between standing height and each physical status very satisfactorily. But the regression curve was more desirable for the elucidation of the relation between standing height and skinfold thickness.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.65-75
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• 2016

In this study, we constructed a database by collecting field pullout test data of the soil nailing using pressurized grouting, and suggested a method to estimate the ultimate pullout resistance using nonlinear regression analysis to overcome the problems of ultimate pullout resistance estimation using graphical methods. The load-displacement curve estimated by nonlinear regression showed a very high correlation with the field pullout test data. Estimated ultimate pullout load by nonlinear regression method was average 29% higher than estimated ultimate pullout load using previous graphical method. A sigmoidal growth model was found to be the best-fitting nonlinear regression model against rapid pullout failure. Further, an asymptotic regression model was found to be the best fit against progressive nail pullout. The unit ultimate skin friction suggested in this research reflected in the domestic geotechnical characteristics and the specifications of the pressurized grouting method. This research is expected to contribute towards establishing an independent design standard for the soil nailing by providing solutions to the problems that occur when using design charts based on foreign research.

• Journal of Nutrition and Health
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• v.9 no.2
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• pp.24-39
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• 1976

The present study was undertaken to investigate the metabolic problems of high carbohydrate and cellulose diets of Korean. Forty males and same number of females of Albino rats, aged $45{\pm}5$days were divided into 95% high carbohydrate (H. CHO)group, 83.8% medium carbohydrate (M. CHO)group, 50% low carbohydrate (L. CHO) group and standard (Stand). group containing 72.2% sugar. Each group was divided into two again-1.55% cellulose group and non-cellulose group, 10 rats each of eight groups in both sexes. Cellulose was added to each of non-cellulose diets in the forms of spinach powder and rice bran. After 14 weeks the rats were sacrificed for chemical analysis and the results were elucidated as follows. (1) H. CHO+Cell. group showed the lowest value in body weight gained and shrinkage of almost all organs, in contrast with this group the L.CHO group showed higher body weight gained than Stand. group. M. CHO+Cell, group showed much the same body weight gained curve as Stand. group. (2) It was observed that cellulose group showed lower F.E.R and P.E.R value than non-cellulose group comparatively. (3) Total nitrogen retention and retention rate were decreaced in H. CHP groups compared with M. CHO or L. CHO groups. (4) The amount of feces was increased due to addition of cellulose to experimental diets and in accordance with the increasing total fecal excretion of nitrogen and glucose was also increased, especially noticeable in fecal glucose excretion. (5) It was noteworthy that serum cholesterol level was decreased due to addition of cellulose in H. CHO group and L. CHO group. (6) M. CHO+Cell. group was designed to reflect the average survey data of Korean diets and there was no significant differences on body weight gained, F.E.R, P.E.R, total nitrogen retention and hematology between M. CHO+Cell. and Stand. group. Total glucose excretion was increased due to dietary cellulose in M. CHO+Cell. group, but it seemed to be no metabolic problems in this group.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.27-31
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• 2011

우리나라의 지점들은 강우자료 관측기간이 다른 나라에 비해 상대적으로 짧고 50년이 넘는 지점이 적기 때문에 지점빈도해석에 의한 확률강우량 추정시 불확실성을 내포하는 문제점을 갖고 있다. 또한, 긴 재현기간에 대한 확률강우량 추정시 더 큰 불확실성이 내포되는데 이러한 이유로 짧은 강우 관측기간의 문제를 보완하고자 지역빈도해석 기법에 대한 연구가 진행되고 있다. 본 연구에서는 전국의 838개소 지점자료로부터 지속기간별 연 최대 강우자료를 추출하였으며, FORGEX 기법의 절차에 따라 확률강우량을 추정하고자 하는 대상지점을 중심으로 네트워크를 구성하였다. 강우자료에 대하여 자료 이상치 보정 후 지속시간별 연 최대강우량 자료를 추출하여 신뢰성 있는 자료를 구축하였다. 구축된 자료를 토대로 중앙값(median)을 이용하여 표준화하였으며 자료 보존기간이 상대적으로 긴 대상지점들을 중심으로 네트워크를 형성하였다. 네트워크별로 pooled points 자료와 netmax 자료를 매년마다 추출하여 구축하였고 이 자료를 이용하여 성장곡선을 유도한 뒤 긴 재현기간에 대한 확률강우량을 구하였다. 또한, 우리나라 강우자료의 지역빈도해석에 적합한 모집단 성장곡선으로부터 netmax 자료의 분포 위치를 조사하기 위하여 강우지점자료를 토대로 기존의 영국에서 사용된 $lnN_e$식이 아닌 새로운 $lnN_e$식을 산정하여 FORGEX기법을 적용하였다. $lnN_e$식은 GEV분포를 토대로 기상청 산하 545개소 지점자료를 이용하여 산정하였다. 지점빈도해석과 FORGEX 그리고 새로운 $lnN_e$식이 도입된 FORGEX기법을 적용하였고, 긴 재현기간에 대한 확률강우량 값을 비교 분석하였다.