• Journal of Apiculture
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• v.34 no.3
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• pp.189-195
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• 2019

Plants release a large variety of volatile organic compounds (VOCs) into the surrounding atmosphere. Floral volatile compounds (FVCs) emitted from many plants is the critical factors for pollinator attraction and defense for adaptation in environments. Recent studies indicate that the chemical components contributing to FVCs play an important role in the honeybee attractiveness to flowers. Olfactory signals are rapidly learned, indicating that foraging behavior results from the association of plant chemicals acting as chemosensory cues for the bees. Solid phase microextraction(SPME)-GC/MS method was applied to analyze the chemical composition of FVCs according to the different species of Robinia spp. The abundant compounds identified in R. pseudoacacia were (Z)-β-ocimene (34.86%) and linalool (35.47%). Those of the tetraploid R. pseudoacacia were (Z)-β-ocimene (35.42%) and α-Farnesene (33.94%). The volatiles of R. margarettae 'Pink Cascade' comprised an abundance of (Z)-β-ocimene (42.73%), (E)-4,8-Dimethylnona-1,3,7-triene (37.23%). Differences in FVCs of the different species of Robinia spp. are discussed in light of biochemical constraints on volatile chemical synthesis and of the role of flower scent in ecology of pollination.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.25-34
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• 2002

The halophytes were investigated on Gyeonggi Bay from Aug. 1999 to Oct. 2001. The survey was conducted at 38 areas including natural salt marshes, dunes, abandoned salt farms and bank areas. During this study 46 species of halophytes were collected in the areas. Among the halophytes the following 7 species were found at natural salt marshes only; Triglochin maritimum L, Carex scabrifolia Steud., Salicornia herbacea L., Suaedu australis (R. Br.) Moq., S. martima Dum., S. japonica Makino, S. malacosperma Hara, on the other hand 8 species at dunes only; Glehnia littoralis Fr. Schm., Cnidium japonicum Miq., Messerschmidia sibirica L., Ixeris repens A. Gray, Corispermum stauntonii Miq., Vitex rotundifolia L. fil., Ischaemum anthephoroides Miq., Carex kobomugi Ohwi. The distributions of halophytes in each regions are as the followings : Isl. Gyodong-do 21 species, Isl. Seokmo-do 10 species, Isl. Ganghwa-do 28 species, Isl. Jangbong-do 16 species, Isl. Sin & Si-do 10 species, Isl. Daemuui-do 23 species, Isl. Deokjeok-do 23 species, Isl. Ijak-do 10 species, Isl. Yeongheung-do 29 species, Soyra 25 species, Isl. Daebu-do 15 species, Ssangsong-ri 6 species, Hogok-ri 16 species, Maehyang-ri 10 species.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.3
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• pp.174-180
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• 2016

Objective: To investigate psychological distress and fertility quality of life (FertiQoL) in infertile Korean women, and to investigate whether a correlation exists between psychological distress and FertiQoL. Methods: Participants in this study were made up of 141 infertile women and 65 fertile women. We conducted a survey on psychological distress (using the Depression Anxiety Stress Scales [DASS]-42 questionnaire) and administered a FertiQoL questionnaire. The levels of stress hormones (adrenocorticotropic hormone [ACTH] and cortisol) in serum were assessed. Results: The scores for depression ($13.7{\pm}8.4$), anxiety ($10.7{\pm}6.4$), and stress ($18.0{\pm}8.3$) among the infertile women were significantly higher than the scores for depression ($9.4{\pm}7.5$), anxiety ($6.6{\pm}6.0$), and stress ($12.2{\pm}8.3$, p<0.001) among the fertile women. There was no difference in the scores for depression ($13.5{\pm}8.2$, $13.8{\pm}8.6$), anxiety ($10.0{\pm}6.2$, $11.5{\pm}6.6$) and stress ($17.7{\pm}8.4$, $18.4{\pm}8.1$) between younger (${\leq}34$) and older (${\geq}35$) participants. The mind-body (r =-0.495) and emotional (r =-0.590) subscales showed a higher negative correlation with stress compared with other scales of psychological distress. At the same time, the social (r =-0.537) and relational (r =-0.385) subscales showed a higher negative correlation with depression. Levels of cortisol and ACTH in infertile women were $9.1{\mu}g/mL$ and 11.9 pg/mL, respectively, which are within normal ranges. Conclusion: The levels of psychological distress and quality of life in infertile Korean women seem to require psychological intervention. This study provides a baseline measurement of psychological distress and FertiQoL in infertile women in Korea, which will be available for developing psychological interventions for infertile Korean women.

• Korean Journal of Plant Resources
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• v.27 no.2
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• pp.188-193
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• 2014

The sap outflow characteristics of Juglans sinensis and J. mandshurica were investigated to evaluate the optimum pruning period of walnut tree that there is a sap spill on dormant. The total period of sap outflow were 34 days for both J. sinensis and J. mandshurica. Total amount of sap outflow per tree in J. sinensis and J. mandshurica were 2,922 mL/tree and 3,135 mL/tree, respectively and the period of sap outflow and non sap outflow between two species were similar. ANOVA analysis showed that the amount of sap outflow was significant differences with day of sap outflow but there were no significant differences between species. From the correlation analysis between air-temperature and sap outflow, daily minimum temperature showed a positive correlation at the 1% level of significance (r=0.56 and r=0.46) for both J. sinensis and J. mandshurica. When branch of walnut tree that diameter is 5 cm cut on the period of sap outflow, the sap flowed down the longest period (48 days) but the sap outflow was not observed after budburst. Therefore, our study supported that the pruning have to avoid the period of sap outflow to reduce sap outflow of walnut tree.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.587-595
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• 2000

The most problems of domestic sewage for BNR(Biological Nutrients Removal) process are deficiency of carbon source and low C/N ratio. Primary sludge fermentation is seemed to be one of the best solutions producing biodegradable organic substrates. Soluble organic materials from sludge fermentation are mainly SCFAs(Short-Chain Fatty Acids) with 2~5 carbon atoms. In this research, it was attempted to apply $A_2/O$ process with the side-stream acid fermenter to improve the nutrients removal efficiency. The result showed that proper SCFAs production is about 3.000mg/L with SRT of 4~5 days. SCFAs yield of approximately 0.10~0.16 mg SCFAs(as COD) per mg of primary sludge(as COD) were achieved. The ratio of acetic. propionic. butyric and valerie acid were 1, 0.7, 0.5 and 0.6. Significant improvements of nutrients removal over 70% in BNR process were observed. thus will reduce the demand for chemical dosing to increase nutrients removal efficiency. When the fermentate was entered $A_2/O$ process, the ratio of phosphate release to substrate uptake amounts to $0.34gPO_4-Pg^{-1}COD$.

• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.661-672
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• 1997

In this paper we introduce the semidiscrete solution of a single-phase nonlinear Stefan problem We analyze the optimal convergence of the semidiscrete solution in $H^1$ and $H^2$ normed spaces and also we derive the error estimates in $L^2$ normed space.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.149-156
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• 2008

To develop a new natural whitening agent for cosmetics, we investigated effects of Acanthopanax sessiliflorum Seeman on melanogenesis. We prepared phenolic acid-rich extract including two phenolic acids, chlorogenic acid and caffeic acid, as predominant constituents from Acanthopanax sessiliflorum Seeman. Phenolic acid-rich extract showed ROS scavenging activities in 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical and xanthine/xanthine oxidase system with the $IC_{50}$ values of $3.43{\pm}0.35{\mu}g/mL$ and $158.91{\pm}1.57{\mu}g/mL$, respectively. Phenolic acid-rich fraction reduced melanin contents of B16 melanoma cells dose-dependantly and the decrease was $27.27{\pm}2.66%$ at a concentration of $100{\mu}g/mL$. And the phenolic acid-rich fraction reduced intracellular tyrosinase activity about $53.67{\pm}8.55%$ at a concentration of $100{\mu}g/mL$. Phenolic acid-rich extract inhibited tyrosinase and TRP-2 expression at protein level. These results suggest that phenolic acid-rich fraction reduced melanin formation by the inhibitions of tyrosinase activity and expression in B16 melanoma cells. Therefore, we suggest that phenolic acid-rich extract could be used as a whitening ingredient in cosmetics.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1137-1143
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• 2010

This paper presents a fatigue design method for plug- and ring-type gas-welded joints, which takes into account the effects of welding residual stress. To develop this method, we simulated the gas-welding process by performing nonlinear finite element analysis (FEA) To validate the FEA results, numerically calculated residual stresses in the gas welds were then compared with experimental results obtained by the hole-drilling method. To evaluate the fatigue strength of plug- and ring-type gas-welded joints influenced by welding residual stresses, the use of stress amplitude $(\sigma_a)_R$, which includes the welding residual stress in gas welds, is proposed $(\sigma_a)_R$ on the basis of a modified Goodman equation that includes the residual stress effects. Using the stress amplitude $(\sigma_a)_R$ at the hot spot point of gas weld, the relations obtained as the fatigue test results for plug and ring type gas welded joints having various dimensions and shapes were systematically rearranged to obtain the $(\sigma_a)_R-N_f$ relationship. It was found that more systematic and accurate evaluation of the fatigue strength of plug- and ring-type gas-welded joints can be achieved by using $(\sigma_a)_R$.

• Tribology and Lubricants
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• v.34 no.6
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• pp.270-278
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• 2018

STS 316L prepared by additive manufacturing (AM) exhibits deterioration of mechanical properties and wear resistance due to the presence of defects such as black-of-fusion defects, internal porosity, residual stress, and anisotropy. In addition, high surface roughness (integrity) of AM products remains an issue. This study aimed to apply ultrasonic nanocrystal surface modification (UNSM) technology to STS 316L prepared by AM to increase the surface hardness, to reduce the surface roughness, and to improve the friction and wear behavior to the level achieved by bulk material manufactured using traditional processes. Herein, the as-received and polished specimens were treated by UNSM technology and their resulting properties were compared and discussed. The results showed that UNSM technology increased the surface hardness and reduced the surface roughness of the as-received and polished specimens. These results can be attributed to grain size refinement and pore elimination from the surface. Moreover, the friction of the as-received and polished specimens after UNSM technology was lower compared to those of the as-received and polished specimens, but no significant differences in wear resistance were found.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.65-71
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• 2010

This study was performed to investigate the inhibiting activity of etridiazole and thiophanate-mthyl on mycelial growth of Rhizoctonia solani and Pythium ultimum and the effect of inoculum density of each pathogen on the control efficacy of the mixture of etridiazole and thiophanate-methyl in a seedling assay test. In mycelial growth inhibition test, $EC_{50}$ values of etridiazole and thiophanate-methyl against R. solani were 15.87 and 9.34 ${\mu}g\;mL^{-1}$, while those were 0.2 and more than $500\;{\mu}g\;mL^{-1}$ against P. ultimum, respectively. Controlling activity of the mixture of etridiazole and thiophanate-methyl against damping-off of pepper and cucumber, caused by R. solani and P. ultimum was tested in a greenhouse. With the inoculation of R. solani, disease incidences of seedling in pepper were 73% and 95% at 0.5% and 1.0% of inoculum concentration, while in cucumber those were 55% and 62% at 1.0% and 2.0%. When P. ultimum was inoculated into soil by 2.0% of inoculum concentration, those in pepper and cucumber were 66.7% and 96.8%, respectively. The efficacy of the mixture was somehow affected by the concentration of R. solani. While each control value of the mixture was 94.4% and 90.7% in pepper and cucumber at low inoculum concentration (0.05%), the efficacy of the fungicide decreased in pepper and cucumber by 70.7% and 72.9% at high concentration of R. solani (0.1% in pepper and 0.5% in cucumber). However, the control value of the mixture was 100% in pepper and cucumber, irrespective of the inoculum concentration of P. ultimum, however, the increase of inoculum concentration in soil did not result in the decrease of the fungicide efficacy.