• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.5
• /
• pp.798-804
• /
• 2015

The distributions of demersal fish along the coast of the South Sea, Korea, were estimated from a hydroacoustic survey and bottom trawl catches in April of 2015. Acoustic data were collected at 38 kHz, and converted into the nautical area scattering coefficient (NASC, m²/n·mile²) for 0.1 n∙mile along eight transects during day and nighttime. Various demersal fish species were collected and the dominant species comprised no more than half of the catch. The estimated acoustic density of demersal fish compared well with the cumulative catch weight from bottom trawl catches in daytime, but showed a low correlation at nighttime. The NASC of pelagic fish determined for anchovy was correlated with water temperature. The combined hydroacoustic and trawl method can be used to understand the spatial/temporal structure and estimate the density of demersal fish in coastal areas.

• Journal of Environmental Science International
• /
• v.20 no.4
• /
• pp.465-482
• /
• 2011

To preserve atmospheric environment of urban areas, it needs to create urban space considering air pollution sources and natural and geographical properties such as wind circulation. According to this study could examine climate and environmental characteristics of Daegu and accordingly suggest a climate map in urban environment and an "advice map" in urban planning. The urban area(area paved with asphalt and concrete) of Daegu has increased by more than five times since 1960. In addition, the analysis of thermal environment through satellite data shows that the surface temperature between a place paved with artificial structures and a farmland shows $10{\sim}20^{\circ}C$ difference during the daytime in the summer. Regarding the parks inhibiting the heat island of a city have the small area of trees, and the road paved with concrete is wide so that they hardly serve as the source of heat absorption. As Apsan is located to the south of Daegu and Palgonsan to the north and Daegu has east high west low type, mountain wind from mountains in the south and north passes a city and delivers heat and air pollutions at night. In the west of Daegue, there is the poorest environment and industrial facilities and environmental basic facilities are mostly located, so large residential complexes that are being built around the industrial facilities as if they set up a folding screen and therefore the poor environment is increasingly worse.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.1
• /
• pp.109-116
• /
• 2005

Wind power and photovoltaic(PV) systems are getting into the spotlight as substitute energy. But problem is happened stability by speed change of wind and the power output of the sun's ray. The power output amount according to velocity of wind power system. System breakdown can happen at change of sudden velocity, typhoon and night. This paper shows a automatic tail safety brake controller based on feedback control using wind velocity. The operation of automatic tail safety controller verified by manual test. PV system is a energy change system by temperature of sun's ray and cell. Maximum power point tracking(MPPT) is used in PV systems to maximize the photovoltaic array output power. In existed PV system is low output and changeable DC voltage for boost and filtering the buck-boost converter use. But, this paper established deformed DC-DC converter. Changed Buck-boost converter's unlined output current to line output current using DC-DC converter. This is effect that reduce ripple of output current. Proved through an output waveform comparison experiment. Finally, tail safety brake controller is established to wind turbine system for stability elevation and DC-DC converter is established on PV system for stability output.

• Restorative Dentistry and Endodontics
• /
• v.20 no.1
• /
• pp.235-249
• /
• 1995

This study was designed to identify the lymphocytes present and to examine the relation between lymphocytes population and clinical symptoms of the pulps clinically diagnosed as normal and irreversible pulpitis. We recorded the history and severity of the pain and performed several clinical tests, before extirpation of vital, irreversibly inflamed pulps in routine endodontic treatment. Then the teeth were divided into two groups. Five teeth, categorized in acute symptom group, had severe spontaneous pain, particularly at night and were extremely sensitive to cold and heat. The other 15 teeth with history of mild to moderate pain and with or without cold or heat responses were categorized as chronic symptom group. Inflamed pulps were also classified into 8 minor groups by presence or absence of signs or symptoms related to the involved teeth, including the presence of pain on percussion, pain on heat and cold stimuli and the periodontal pocket depth. All extirpated pulps were immediately immersed in ultra low-temperature freezer($-74^{\circ}C$), and they were sectioned $6{\mu}m$ in thickness. Specimens were stained using three-stage indirect immunoperoxidase techniques(DAKO, LSAB kit) and monoclonal antibodies for detecting the presence of T lymphocytes(T), B lymphocytes(B) and helper(T4) and suppressor(T8) lymphocytes. Following results were obtained; 1. All the examined normal and inflamed pull) tissues had positive staining for T lymphocytes and T helper and T suppressor cells. But B cells were observed only in inflamed pulp. 2. Statistically more T and B cells were observed in acute symptom group as compared with chronic symptom group(p<0.05). 3. Cell ratio of BIT in acute symptom group were significantly higher than that of chronic symptom group(p<0.05). 4. Only B cells were significantly increased in the percussion positive group than the number of B cells in percussion negative group(p<0.05). 5. No differences were observed in the number of different cell types among other minor groups.

• Horticultural Science & Technology
• /
• v.19 no.1
• /
• pp.43-47
• /
• 2001

This study was conducted to investigate the integrated control strategy against pear black leaf spot disease. Using indicator plant PS-95 we selected six virus-free trees (cv. Niitaka) from commercial orchards in the major pear production area. Disease symptom by pear black leaf spot in the shoot of pear (Niitaka) has been successfully inhibited by heat treatments for 3 weeks at temperature of $40^{\circ}C$ (day) and $32^{\circ}C$ (night) or 4 weeks at $37^{\circ}C$ and $30^{\circ}C$, respectively. However, survival rate of the shoot tips on stocks was low. Seven cultivars Niitaka, Imamura- aki, Waseaka, Nijisseiki, Wasenijisseiki, Shinsetsu and Whangkeumbae produced visible symptoms in the first year after inoculation with the virus. Other 11 selections remained symptomless. Two resistant cultivars Suwhangbae and Gamcheonbae were selected, which showed high fruit quality. It is recommended that these cultivars could be top-grafted onto the infected Niitaka trees to overcome the damage caused by the disease in the orchard.

• Journal of Korean Society on Water Environment
• /
• v.37 no.1
• /
• pp.20-31
• /
• 2021

In this study, an analysis of the characteristics of organic matter and nitrogenous oxygen demand (NOD) of 17 sewage effluent and wastewater treatments was conducted. High CODMn and carbonaceous biological oxygen demand (CBOD) concentrations were observed in the livestock treatment plants (LTP), wastewater treatment plants(WTP), and night soil treatment plants (NTP), but the highest NOD concentration and contribution rates of NOD to BOD5 were found in sewage treatment plants (STP). There was no significant difference in the CBOD/CODMn ratio for each of the six pollution source groups, but the LTPs, WTPs, and NTPs all showed relatively high CODMn concentrations in their effluent samples, indicating that they are facilities which discharge large amounts of refractory organic matter. The seasonal change of NOD in all facilities' effluent was found to be larger than the seasonal change of CBOD, and data results also revealed an elevation of NOD and NH3-N concentration from December to February, when the water temperature was low. There was no significant difference in NH3-N concentration in relation to pollution source group (p=0.08, one-way ANOVA), but the STP, which had a high NOD contribution rate to BOD5 of 48%, showed a high correlation between BOD5 and NOD (r2=0.95, p<0.0001). These results suggest that the effect of NOD on BOD5 is an important factor to be considered when analyzing STP effluent.

• Korean Journal of Weed Science
• /
• v.14 no.2
• /
• pp.120-127
• /
• 1994

To establish an efficient herbicide screening method for purple nutsedge(Cyperus rotundus) control, its sprouting characteristics, tuber production and responses on several herbicides were investigated under greenhouse condition. The tubers stored at $4^{\circ}C$ after sterilization with the diluted prochloraz(Spotac) solution showed higher sprouting than the non-sterilized did. The harvested tubers were not dormant, and the sterilized tubers which stored at low temperature had a sprouting capability of about 80% after 6 months. If the fresh weight of purple nutsedge tubers was decreased to below 48%, they could not sprout. However, the tubers soaked in water and then stored at low temperature could sprout by 88% even 6 months later. Sprouting and initial growth of tuber were much better at $35^{\circ}C$-day/$25^{\circ}C$-night than at 30/$20^{\circ}C$ or 25/$15^{\circ}C$. The half-sected tubers, which were prepared by setting the intact tuber of above 1.2g latitudinally, were shown similar initial growth to the intact but those sected crucifically were not. These results suggest that the half-sected tuber itself can be used as a material on herbicide screening. About 1000 tubers could be harvested when 10 tubers planted in a pot($56{\times}35{\times}16cm$) filled with the artificial soil were cultivated in greenhouse of $35^{\circ}C$-day/$25^{\circ}C$-night for 3 months(April-July, 1993). Chlorimuron, Bentazon and Norflurazon were selected as the standards for the screening because of providing relatively effective control on purple nutsedge in both soil-surface and foliar spray treatment.

• Korean Journal of Environmental Biology
• /
• v.36 no.2
• /
• pp.117-123
• /
• 2018

In this study, the efficiency of photosynthetic electron transfer according to LED color temperature was verified in order to find a way to efficiently grow trees under night illumination. The experiment was carried out with White treatment, Warmwhite treatment, and non-treatment with donarium cherry. The study uses to a method for analyzing and evaluating the color temperature of an LED light source by photochemical analysis. We found that all treatments 115 DAT of maximum fluorescence amount(P) had the lowest. In the treatment using white light and the Warm-white light, the T amount of florescence of the late stage during the transition of the J-I level was increased, and the photosystem I electron transfer efficiency was decreased. Therefore, the electron transport efficiency of $RE1_O/CS$ and RE1o/RC were reduced. Especially, compared to Warmwhite, the light intensity increased greatly in the white-light treatment, The $PI_{TOTALABS}$ of 7 DAT was the highest value, but it was decreased to the lowest value on 115 DAT. This study has shown that the white treatment was low in electron transfer efficiency and soundness. Warmwhite-light treatments showed lower stress.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.31 no.1
• /
• pp.9-15
• /
• 1986

To establish an efficient light control method using three covering materials on tunnel shaped rice seed-bed at greening stage after seedling emergence, four rice cultivars, Nampungbyeo, Taebaegbyeo, Seonambyeo, and Seomjinbyeo were sown on 15 April and 10 May in 1983 and 1984 respectively. After seedling emergence by a simplified emerging methods the seedling boxes were moved onto tunnel shaped seed-bed which was covered with combined matrials of PE film, silverpoly sheet, and spunbonded polyester fabric. For machine transplanting of rice seedlings in cases of early season and optimum season seeding in central part of Korea, PE film tunnel with silverpoly mulched, and PE film tunnel methods with spunbonded polyester fabric mulched reduced injuries of non-parasitic seedling damping-off and a albinism as affected by it, protected rice seedlings from injuries by extremely low temperature in the night, and reduced less differences in diurnal temperature than those in the other covering methods. At late season seeding for double cropping system of paddy field in southern part of Korea, a single silver-poly or a single spunbonded polyester fabric-covered tunnel method showed good green seedlings, and prevent-ed extreme rising of diurnal temperature by light interception in the tunnel.

• Korean Journal of Weed Science
• /
• v.13 no.1
• /
• pp.44-54
• /
• 1993

This experiment was conducted to understand the environmental factors affecting growth and tuber formation such as temperature, day length, tight intensity, water condition and cutting time of Eleocharis kuroguwai Ohwi. Plant height, shoot number and dry weight of E. kuroguwai were higher at high temperature, 25/$25^{\circ}C$ (day/night), while nitrogen content was higher at low temperature, 20/$15^{\circ}C$. Plant height was more affected by water temperature, while shoot number and dry weight were more affected by air temperature. Contents and absorption of nitrogen, phosphorus, and potassium in top parts of E. kuroguwai were higher under greater difference between air and water temperatures, i.e., 18/$28^{\circ}C$ and 28/$18^{\circ}C$. The number and weight of tubers were increased under greater difference between air and water temperatures, i.e, 18/$28^{\circ}C$ and 28/$18^{\circ}C$, while they were inhibited at low or high air/water temperatures (18/$18^{\circ}C$ or 28/$28^{\circ}C$). Tubers of E. kuroguwai were formed at 8-or 12-hour day length, however, no tuber was formed at l6-hour day length. Photoinductive period for tuber initiation of E. kuroguwai was between 30 and 45 days after emergence, and the induction period of short-day treatment was less than 10 days. Tuber number and weight were reduced by shading due to inhibition of the growth of top and underground parts. Number of days from planting to tuber initiation was shortned as planting time was delayed and plant height, dry weight, and tuber number were also reduced by delayed planting. Tuber number at l0 to 15cm water depth was decreased 63 to 75% as compared with 1 to 5cm water depth. Tuber number and dry weight were not affected by the size of tubers at planting. Due to the reduced growth of top and underground parts, tuber number and dry weight of E. kuroguwai were decreased by delayed shoot cutting. The critical cutting time to inhibit the growth of E. kuroguwai was about 70 days after emergence.