• 한국해양학회지
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• v.30 no.4
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• pp.237-249
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• 1995

To understand the cross-sectional structures of temperature, salinity and current across the Korea Strait, field measurements were carried out for the period of May 2 to 20, 1994. Using the R/V Tam Yang, detailed CTD profiles and ADCP records were obtained and used to examine the mean and variability field on two time scales (15 days and 25 hours). A sharp coastal front in the middle of the Korea Strait exists across which two different water masses, i.e., warm and saline water in the eastern side and cold and less saline water in the western side are neighboring. We observed highly variable field of T and S apparently caused by the westward movement of warm and saline water mass. Short-term fluctuations of T and S in the middle layer are remarkable and their importance was analysed as the first Eigen mode accounting for more than 50% of total variances. The currents in th Korea Strait are strongly influenced by tidal currents with spring and neap variation whose maximum speed ranges 80-90 and 60-70 cm/s respectively near the central portion of the channel. Strong southward tidal current could even mask the Tsushima Current completely. Results of harmonic analysis show that the magnitudes of semidiurnal, diurnal and mean components of currents are comparable to each other at spring and neap tide conditions. The volume transport across the western channel of the Korea Strait were estimated to be 2.1 Sv at neap tide condition and 3.4 Sv at spring tide condition.

• Korean Journal of Medicinal Crop Science
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• v.26 no.3
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• pp.248-253
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• 2018

Background: Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results: The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. After May fumigation, the sowing date of maize was delayed by 15 days and thus its dry weight was decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, $NO_3$, $P_2O_5$, and K significantly. Maize cultivation after May fumigation decreased fungi population and the ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different between treatment of May and September, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusions: Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by the amendment of mineral composition and microorganism in fumigated soil.

• Analytical Science and Technology
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• v.18 no.4
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• pp.344-354
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• 2005

This study was carried out to evaluate the performance of a small chamber sampling and analytical method for the measurement of total volatile organic compounds (TVOC) and formaldehyde (HCHO) emission from building materials. While VOC was determined by the adsorbent tube sampling and sequential thermal desorption coupled with GC/MSD analysis, formaldehyde sampled with DNPH-silica cartridge was analyzed by HPLC. Wide-range performance criteria such as repeatability, desorption efficiency, emission chamber recovery test, duplicate precision, breakthrough volume and method detection limits were investigated for the evaluation of small chamber method. The overall precision of the small chamber sampling and analytical methods was estimated within 20~30% for target compounds. In conclusion, this study demonstrated that the small chamber sampling and analytical method can be reliably applied for the measurement of building materials pollutants.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.1-10
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• 2012

This paper presents an experimental result and suggests the confinement effect of headed cross tie in reinforced concrete(RC) columns subjected to cycling horizontal loads under constant axial load. Five RC columns specimens were manufactured, taking confined type of transverse reinforcement, whether or not using cross tie, end detail of cross tie (hooked or headed), and axial stress in column as major variables, Cyclic horizontal load applied to the columns under constant axial stress and the effect of cross tie to structural capacity of column was evaluated from the test. The column without cross tie failed showing bending deformation of hoop with crack in core concrete at low horizontal load while the column with cross tie showed quite improved strength and ductility by suppressing bending deformation of hoop as well as buckling of longitudinal bar at once even after crack in core concrete. At high lateral displacement, the column with hooked cross tie showed the failure pattern loosing the confining force of cross tie since the $90^{\circ}$ hooked part of cross tie was stretched out and the cracked core concrete lumps were came off. However, the column with headed cross tie showed very stable behavior since the head of cross tie effectively confined the hoop and longitudinal bars even at high lateral displacement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.188-197
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• 2010

This paper presents research result to study the change of structural capacity of reinforced concrete beams with various shear reinforcement ratios after damage by fire load. In addition, fundamental data are given in order to predict the strength variation of RC member due to fire damage by evaluating the previous calculation method codified in codes. Nine RC beam specimens were made and exposed to the fire controled by the standard fire curve. And the structural capacity was evaluated through a failure test under simple support condition. Previous code formula, ACI code and Eurocode were reviewed and used for the calculation of the strength of specimens damaged by fire. From the test, RC beam specimens exhibited very brittle failure when it exposed to fire controled by standard fire curve during more than one hour. And this failure pattern tended to be more serious when shear reinforcement ratio decreased or fire loading duration increased. From the evaluation of the calculation process in code, the change of strength due to fire can be properly predicted if the damage of materials is well defined.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.972-979
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• 2014

This study was conducted to investigate the physiological characteristics of water and ethanol extracts from leaves and stems of Achyranthes japonica. The highest contents of total polyphenol and flavonoid compounds were 58.27 and 42.22 mg/g in water extract from leaves, respectively. The protein content was the highest at 16.42 mg/g in water extract from leaves. Ethanol extract from stems showed the highest content of reducing sugars at 11.35 mg/g. In the measurement of electron donating ability (EDA), ethanol extract from stems showed the highest EDA at 93.41% at a concentration of 1.0 mg/mL. Superoxide dismutase-like activity of ethanol extract from leaves was the highest at 8.13% at a concentration of 1.0 mg/mL. In the analysis of nitrate scavenging activity, water extract from leaves showed the highest activity at 94.90% at pH 1.2, and the activity increased as concentration increased and pH decreased. In the measurement of xanthine oxidase inhibition, ethanol extract from stems showed the highest inhibitory activity at 66.67% at a concentration of 1.0 mg/mL. Especially, nitrate scavenging activities of water extract from leaves were the highest under all pH conditions. These results verify that extracts from leaves of A. japonica have strong antioxidant activity and can be used as an effective antioxidant source for nutraceutical foods, medicines, and cosmetic stuffs.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.300-306
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• 2016

Recently, the incidence of oak wilt disease has been increasing in Korea, resulting in an increasing number of dead trees. In this study, we performed sawdust bag cultivation of shiitake (Lentinula edodes) using oak wilt-diseased logs and measured the antioxidant activities of the resulting mushrooms. For sawdust media, 4 types of logs (healthy, infected, dead, and fumigated ones) were used. As inocula, three strains of L. edodes (NIFoS 764, Sanjo 701ho, and Sanmaru 2ho) were used. The productivity of L. edodes from dead logs was similar to that from healthy logs. Except for the Sanmaru 2ho strain, fumigated logs and infected logs yielded a lower productivity of L. edodes compared to healthy logs. In terms of antioxidant activity, L. edodes grown on sawdust from fumigated logs showed higher values than those from other logs.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.121-131
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• 2017

We evaluated the antioxidant properties of Lentinula edodes upon sawdust bag cultivation with 5 oak substrates: Quercus acutissima, Q. mongolica, Q. serrata, Q. aliena, and Q. variabilis. We found that the optimal extraction conditions were 70% (v/v) methanol shaken at 150 rpm at $25^{\circ}C$ and 150 rpm for 24 h. The methanolic extracts from L. edodes contained high phenolic and flavonoid contents, they also exhibited stronger antioxidant activities. The total phenolic contents and total flavonoid contents of the mushroom extracts ranged from 2.37 to 3.12 milligrams of gallic acid equivalents per gram of dried mushroom (mg GAE/g) and 0.48 to 0.48 milligrams of quercetin equivalents per gram of dried mushroom (mg QE/g), respectively. In addition, the mushroom extracts exhibited 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (15.8% to 89.4%) at 2 to 10 mg/mL, ferric reducing antioxidant power (0.153 to 0.425) at 5 to 20 mg/mL, and reducing power (0.078 to 0.359) at 5 to 20 mg/mL, respectively. Q. aliena more effectively increased total phenolic contents, total flavonoid contents, and antioxidant activities than the other oak substrates.

• Korean Journal of Logic
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• v.8 no.1
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• pp.23-46
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• 2005

The purpose of the paper Is to discuss and estimate early Popper's theory of probability, which is presented in his book, The Logic of of Scientific Discovery. For this, Von Mises' frequency theory shall be discussed in detail, which is regarded as the most systematic and sophisticated frequency theory among others. Von Mises developed his theory to response to various critical questions such as how finite and empirical collectives can be represented in terms of infinite and mathematical collectives, and how the axiom of randomness can be mathematically formulated. But his theory still has another difficulty, which is concerned with the inconsistency between the axiom of convergence and the axiom of randomness. Defending the objective theory of probability, Popper tries to present his own frequency theory, solving the difficulty. He suggests that the axiom of convergence be given up and that the axiom of randomness be modified to solve Von Mises' problem. That is, Popper introduces the notion of ordinal selection and neighborhood selection to modify the axiom of randomness. He then shows that Bernoulli's theorem is derived from the modified axiom. Consequently, it can be said that Popper solves the problem of inconsistency which is regarded as crucial to Von Mises' theory. However, Popper's suggestion has not drawn much attention. I think it is because his theory seems anti-intuitive in the sense that it gives up the axiom of convergence which is the basis of the frequency theory So for more persuasive frequency theory, it is necessary to formulate the axiom of randomness to be consistent with the axiom of convergence.

• Korean Journal of Medicinal Crop Science
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• v.25 no.3
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• pp.175-182
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• 2017

Background: Ginseng is a perennial crop grown for more than four years in the same place. Therefore, it is highly affected by the soil environment, especially nutrients in the soil. The present study was carried out to investigate to the influence of boron and iron concentrations on the physiological status, growth, and mineral uptake of ginseng to obtain the basic information for diagnosing a physiological disorder in ginseng plants. Methods and Results: The boron and iron concentrations were controlled at 3, 30, 150, 300 and 2, 20, 100, $200mg/{\ell}$, respectively. When treated with $150mg/{\ell}$ of boron, the ginseng plants showed yellowing or necrosis symptoms at the edge or end of their leaves. Compared with the $3mg/{\ell}$ treatment, the root weight decreased by 13 and 24% in the 150 and $300mg/{\ell}$ treatments, respectively. When treated with $20mg/{\ell}$ of iron, the ginseng plants showed yellowing between the veins of the leaves followed by the formation of brown spots. The root weight gradually decreased with increasing iron concentration. Approximately 55% decrease in root weight was observed upon treatment with $200mg/{\ell}$ of iron. Conclusions: The boron toxicity occurs in the leaves of ginseng at the boron concentration of approximately 1,900 mg/kg or more. The iron toxicity occurs at the iron concentration of approximately 120 mg/kg for leaves and 270 mg/kg for roots.