• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.666-672
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• 1997

Twenty years' daily mean air temperature data was used to calculate the critical early seeding date(CESD), the optimum heading date(OHD), the critical late heading date for stable ripening(CHDR) and the critical late ripening date(CLRD) for rice seeded on dry paddy in different agroclimatic zones in Korea. The CESD was defined as the first day with mean air temperature of 13$^{\circ}C$, and the OHD as the first day of the 40 consecutive days with mean air temperature of 22$^{\circ}C$ or above after heading. The CHDR was defined as the date after which the cumulative daily mean air temperature would be at least 76$0^{\circ}C$. Lastly, the CLRD was defined as the last day when daily mean air temperature remains above 15$^{\circ}C$. This information was used for the estimation of periods from the earliest date of seeding to optimum heading date, the latest possible date of heading and the latest possible date of ripening in respective regions. For instance, in Suwon, those respective periods mentioned were found to be 104days, 124days, and 165days.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.189-194
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• 1996

The effects of scorpion (Leiurus quinquestriatus hebraeus, Lqh) venom were evaluated on the activities of microsomal $Ca^{2+}-ATPase$ and $Ca^{2+}$ release channel prepared from the epithelial cells of pig airway. Whole venom of Lqh $(120\;{\mu}g/ml)$ increased the activity of microsomal $Ca^{2+}-ATPase$ about 32% in the tight-sealed microsomes and about 28% in the Triton X-100-treated or $Ca^{2+}$ ionophore A23187-treated leaky microsomes. Thapsigargin, a specific antagonist of $Ca^{2+}-ATPase$, inhibited 42% of total ATPase activity and also completely blocked the effects of Lqh venom, suggesting that Lqh venom directly activiates the microsomal $Ca^{2+}-ATPase$. In order to determine if Lqh venom increases the microsomal uptake of $^{45}Ca^{2+}$, Lqh venom was added in the uptake medium. The Lqh venom increased microsomal $^{45}Ca^{2+}$ uptake up to ${\sim}20%$ and the increase was only observed when heparin, an antagonist of $InsP_3$ receptor channel, was added in the uptake medium. Lqh venom in the absence of heparin unexpectedly decreased the rate and the amount of $^{45}Ca^{2+}$ uptake. These results were explained by simultaneous increases in $^{45}Ca^{2+}$ release as well as $^{45}Ca^{2+}$ uptake by Lqh venom. Lqh venom itself increased the release of $^{45}Ca^{2+}$ as much as $^{45}Ca^{2+}$ release by $4\;{\mu}m\;InsP_3$, implying that Lqh venom also activates $InsP_3$ receptor, microsomal $Ca^{2+}$ release channel. Based on these results, we suggest that the Lqh venom consists of at least two components; one activates the $InsP_3$ receptor and the other avates the $Ca^{2+}-ATPase$. Currently we a investigating the chemical and electrophysiological properties of the active components of Lqh venom.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.36-43
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• 1993

Differences in community space of weed and rice were investigated among five types of rice (Oryza sativa L.) cultivation. The five types employed were three transplanting cultivations such as conventional hand transplanting, machine transplanting with 30-day-old seedling, and machine transplanting with 10-day-old seedling and two direct-seedlings such as flood direct-seeded rice by pregerminated seed and dry direct-seeded rice by dry seed. The greatest competition between rice and weeds as determined by growth rate of rice was found in between 10 and 11 weeks after transplanting (WAT) and/or seeding, irrespective of cultivation types. Competition injury due to weeds was greater in transplanting with 10-day-old seedling than with 30-day-old seedling. The greatest injury in growth of rice was found in direct-seeded cultivation. In transplanting cultivations space occupation by rice in lower than 80 cm height level was low as compared with that by weeds. Plant heights of dominant weeds such as E. crus-galli and E. kuroguwai were shorter by heading date, but taller after the heading date than those of rice. In direct-seeding community space was mainly occupied by the weeds. The pattern of community structure and competition injury caused by weeds showed a similar tendency obtained on the basis of species distribution, number, and dry weight of the occurred weeds.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.987-993
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• 2005

A bacterium, producing a fibrinolytic enzyme, was screened from a decaying rice plant. The bacterium was identified as Bacillus subtilis by morphological, biochemical, and physiological properties and named Bacillus subtilis BK-17. The fibrinolytic enzyme (BK) was purified from supernatant of Bacillus subtilis BK-17 culture broth. The molecular weight was 31 kDa as determined by SDS-PAGE. The effect of temperature, pH, and plasminogen on the activity of the bacillokinase (BK) was analysed and the activity was compared with urokinase. The optimal temperature and pH were $50^{circ}C$ and pH 7, pH 8, respectively. The BK activity was inhibited to $45\%$, $35\%$, and $23\%$ with 1mM EDTA, $Zn^{2+}$, and $Ca^{2+}$, respectively. However, $Mg^{2+}$, $Mn^{2+}$, and $Co^{2+}$ ions did not have any significant effect on the enzyme activity The BK showed the artivity in the both plates, plasminogen-free fibrin plate and plasminogen-rich fibrin plate. The result indicates that the BK can directly act the fibrin. In comparison of fibrinolytic activity with urokinase on the fibrin plate, the BK shows about 20 folds higher activity than that of the urokinase.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.74-84
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• 1998

A doubly resonant ultrasonic transducer has been designed as an attempt to increase the bandwidth of underwater transducers. The dual resonance conditions were accomplished by attaching a single acoustic matching layer on the front face of a Tonpilz transducer consisted of an aluminum head, a piezoelectric ring, a brass tail and a prestress bolt. A modified Mason's model was used for the performance analysis and the design of transducers, and the constructed transducers were tested experimentally and numerically by changing the impedances and thicknesses of the head, tail and matching layers in the water tank. Two distinct resonance peaks in the transmitting voltage response(TVR) of a developed transducer were observed at 34.3 and 40.4 kHz, respectively, with the difference frequency of 6.1kHz and the center frequency of 37.2kHz. The values of TVR at these frequencies were 136.5 dB re $1\;\muPa/V$ at 34.3 kHz and 136.8 dB re $1\;\muPa/V$ at 40.4 kHz, respectively. Reasonable agreement between the experimental results and the numerical results was achieved. From this result, it is expected that the generation of the distinct resonances at any two desired frequencies can be achieved through the proper choice of the matching layer to provide the impedance transformation between the transducer and the medium.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.419-426
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• 2010

This study was conducted to investigate the effect of different castration ages on meat quality and sensory properties of Korean native black goats over 410 days. For the experiment, 32 heads of goat (eight heads/4 treatment) were subjected to either a control (5 month non-castration), T1 (7 month castration), T2 (5 month castration) or T3 (3 month castration). The total weight gain for Korean native black goats was highest in the T2 group after feeding for 410 days and the weight gain/day tended to be similar to the total weight gain. The total feeding amounts were lowest (410.82 kg) in T3; however, the feed intake ratio was 16.39 in T2, indicating that it had the best feed efficiency among groups. The cooking loss and drip loss of the Korean native black goats was highest in the control, being 35.53% and 2.08%, respectively (p<0.05), while the total cholesterol of the treatments was higher than that of the control (p<0.05). Moreover, the overall sensory evaluation of the treatment groups was low, indicating that there was more meat flavor when compared to the controls in terms of juiciness, tenderness, flavor, texture, black goat off-flavor and overall evaluation (p<0.05). T2 was found to have the best meat flavor upon sensory evaluation. Additionally, the meat color of the control showed the highest $L^*$ value and Hue value, while T3 showed the highest $a^*$ value (3.61) and T2 showed the highest $b^*$ value and Chroma. The composition of fatty acids was 53.76% oleic acid in T2, while the amounts of Mono-unsaturated fatty acid (MUFA) were highest in T1 and T2 (p<0.05). As a result, the MUFA/SFA ratios of T1 and T2 were higher than those of the control (p<0.05). In conclusion, it is most advantageous to castrate Korean native black goats at the age of 5 months for the best performance and meat quality.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of Korean Classical Literature and Education
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• no.33
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• pp.121-152
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• 2016

The purpose of this study is to illustrate the history of the Cheonsu-Temple天壽寺 and to describe the echo verse poem trend with regard to 'Waiting'待人 and why it is beautiful. The Cheonsu-Temple was located in the outskirts of Gaesung開城, the capital city during the Corea高麗 Dynasty. However, the temple was destroyed when the dynasty collapsed. Cheonsu-Station天壽院 was built amidst the temple ruins, as the temple was an important traffic point. The Cheonsu-Pavilion天水亭 was built in 1476 by Yi-Ye李芮 in the station's neighborhood. The station and the pavilion were completely ruined during the 17th century. Many poets visited the Cheonsu-Temple and composed poems in the latter part of the Corea Dynasty. 'Waiting'待人, written by Choi-Sarip崔斯立, -is the most famous work. Following this work, many poets composed echo verse poems 'Waiting' work that represented the anxiety of waiting for an old friend in front of the Cheonsu-Temple. The following is a highlighted verse: So many people who look like the old friend come to me, but it turned out no one was the man. This work is very picturesque. Over twenty echo verse poems 'Waiting' are categorized in three periods. They compared the "present" to the past by using the Zhenglingwei丁令威 origin from the former Joseon朝鮮 period. In the middle of Joseon period, Jungjong中宗 visited Cheonsu-Station and composed an echo verse poem 'Waiting'. The official literaries also composed poems there. In their works, they presented the collapse of the Corea Dynasty as inevitable and the construction of Joseon Dynasty as something reasonable. Cheonsu-Station was ruined in 17th century, followed after by the ruin of the Cheonsu-Pavilion. It appears that the echo verse poems to 'Waiting' in the latter Joseon period represented the ruin of the Cheonsu-Temple, the Cheonsu-Station, and the Cheonsu-Pavilion.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.219-228
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• 2009

The construction procedures and artificial turf maintenance program on golf course definitely influence on the distortion of its environment. Soil microbial communities in soil profile were affected directly by those practises on turf areas. In Jeju island, the environmental impact assessment has been required to apply the first quality class granular activated carbon(GAC), which has a high absorbent character to agricultural chemicals, on the soil profiles of golf green system to reduce the pesticide leaching to ground water. This research was carried out to analyze the changes of microbial communities and chemical properties on soil profiles where GAC had been applied at the construction stage at two golf courses in Jeju. The changes of soil microbial population and chemical properties associated with construction methods of soil profile and agrochemical management program were analyzed by monthly at the surface and sub-soil profiles during April through October, 2007. The total numbers of bacteria and fungi, soil moisture content, soil physio-chemical properties were measured on greens and fairways of the both golf courses with different GAC treatment on the green and fairway soil profiles. The results showed that GAC had positive effects on the water holding capacity, pH and EC, however, it did not improved the holding capacity of available nutrients ${NO_3}^-,{NH_4}^+$, and phosphorus by its sorption phenomenon. In microbial count test, the total numbers of bacteria and fungi showed a great variation during sampling dates. That may directly relate to the agrochemical application, however, the ratio of total bacterial number versus total fungus number showed a constant value on a sub-soil of 15~30cm depth. Thus, the construction method of GAC in soil profile, and application of fertilizer and pesticide, both impacted on the changes of microbial population. It's means that the construction method of soil profile and turf management using agro-materials might greatly affect on the turfgrass culture and the environment of golf course.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.31-38
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• 1989

A series of experiments was conducted to determine the contents and distribution of amino acids in the hydrolysates of humic acids extracted from 3 plant materials. Wild grass hay, and leaves of forest trees were used in this study. Seventeen amino acids were analyzed and their amounts determined. Results obtained from the experiments are summarized in the following: 1. Contents and distribution of hydrolyzable amino acids in the humic acid fractions depend on the kind of plant materials and the allowed time for humification. 2. Neutral amino acids was the largest part of the total amino acids, followed by acidic amino acids, and basic amino acids. 3. The total amounts of amino acids in the hydrolyzable humic acid fractions of well humified residues were in the following order: wild grass hay > leaves of deciduous trees > leaves of coniferous trees 4. In general the relative amounts of lysine increased with humification progressing. S. Glycine and glutamic acid were the two major amino acids in common for the hydrolysate of humic acids extracted from well decomposed residues of plant materials. Alanine, glutamic acid, glycine, aspartic acid and leucine were the five major amino acid in common in raw materials without exception. 6. Arginine appeared to be absent in any of the hydrolysates of humic acids from well humified plant materials. 7. Phenylalanine and tyrosine were present in all hydrolysates and their relative contents increased with the humification of plant materials.