• Korean Journal of Poultry Science
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• v.7 no.2
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• pp.54-76
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• 1980

A survey was conducted to determine the status of health and productivity of poultry farms in Korea. Area included Was Kyunggido where exist nearly 50% of national poultry population. From this area, 41 layer and 34 broiler farms covering 21 Countries were selected randomly for the survey. When farms were divided in the operation size, 95.1% of layer and 82.3% of broiler farms were classified as business or industrial level while the rest were managed in a small scale as part time job. Generally layer farms had been established much earlier than broiler farms. Geographically 10.7% of layer farms were sited near the housing area such as field foreast and rice field. No farms were located near the seashore. The distance from one farm from the other was very close, being 80% of the farms within the distance of 1km and as many as 28% of the farms within loom. This concentrated poultry farming in a certain area created serious problems for the sanitation and preventive measures, especially in case of outbreak of infectious diseases. Average farm size was 5,016${\times}$3.3㎡ for layers and 1,037${\times}$3.3㎡ for broilers. 89.5% of layer ana 70.6% of broiler farms owned the land for farming while the rest were on lease. In 60% of layer farms welters were employed for farming while in the rest their own labour was used. Majority of farms were equipped poorly for taking necessary practice of hygiene and sanitation. The amount of disinfectant used by farms was considerably low. As many as 97.6% of lave. farms were practised with Newcastle(ND) and fowl pox(F$.$pox) vaccine, whereas only 43.6% and 5.1% of broiler farms were practised with ND and F$.$pox vaccine, respectively. In 17-32.7% of farms ND vaccine was used less than twice until 60 days of age and in only 14.6% of farms adult birds were vaccinated every 4months. Monthly expense for preventive measures was over 200,000W in 32% of farms. Only 4.9-2.7% of vaccine users were soaking advice from veterinarians before practising vaccination, 85% of the users trusted the efficacy of the vaccines. Selection of medicine was generally determined by the farm owner rather than by veterinarans on whom 33.3% of farms were dependant. When diseases outbroke, 49.3% of farms called for veterinary hospital and the rest were handled by their own veterinarians, salesmen or professionals. Approximately 70% of farms were satisfied with the diagnosis made by the veterinarians. Frequency of disease outbreaks varied according to the age and type of birds. The livabilities of layers during the period of brooding, rearing ana adultwere 90.5, 98.9 and 75.2%, respectively while the livalibility of broilers until marketing was 92.2%. In layers, average culling age, was 533.3 day and hen housed eggs were 232.7. Average feed conversion rates of layers and broilers were 3.30 and 2.48, respectively. Those figures were considerably higher than anticipated but still far lower than those in developed countries.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.277-286
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• 2006

Population ecology of Cobitis tetralineata was examined at Churyeong Stream, Seomjin River, Korea. C. tetralineata inhabited on the sand bottoms with $10{\sim}20cm/see$ in current velocity, and $30{\sim}150cm$ in water depth. This species was active on the sand during the daylight hours from March to October, but they hibernated in the inside of the sand during the winter season. Sex ratio of female to male was 1:0.57, and female was $20{\sim}30mm$ (TL) larger than male. The age group of C. tetralineata (female) population showed that the $20{\sim}40mm$ group is 0+ years old, the $45{\sim}65mm$ group 1+ years old, the $65{\sim}90mm$ group 2+ years old, and the group longer than 90 mm over 3 years old. Males $13{\sim}14$ months old after hatching had lamina circularis at the base of its pectoral fin as a secondary sexual character. And in its spawning season, lateral color pattern of male was changed as a sexual dimorphism. The spawning season may be from late June to middle July, $22{\sim}26^{\circ}C$ water temperature. The average number of mature eggs in ovary was about $1,288{\pm}583(474{\sim}2,976)$, egg diameter was about $0.98{\pm}0.1mm$. C. tetralineata fed mainly on Chironomidae, Arcellidae, Branchioda and Algae. The feeding rate was the highest in April and September, but they did not fed in the winter.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.37-42
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• 2003

Purpose : Computed tomographic equipment is essential for diagnosis by means of radiation. With passage of time and development of science computed tomographic was developed time and again and in future examination by means of this equipment is expected to increase. In this connection these authors measured rate of scatter ray generation at front of lead glass for patients within control room of computed tomographic equipment room and outside of entrance door for exit and entrance of patients and attempted to ind out method for minimizing exposure to scatter ray. Material and Method : From November 2001 twenty five units of computed tomographic equipments which were already installed and operation by 13 general hospitals and university hospitals in Seoul were subjected to this study. As condition of photographing those recommended by manufacturer for measuring exposure to sauter ray was use. At the time objects used DALI CT Radiation Dose Test Phantom fot Head (${\oint}16\;cm$ Plexglas) and Phantom for Stomache(${\oint}32\;cm$ Plexglas) were used. For measurement of scatter ray Reader (Radiation Monitor Controller Model 2026) and G-M Survey were used to Survey Meter of Radical Corporation, model $20{\times}5-1800$, Electrometer/Ion Chamber, S/N 21740. Spots for measurement of scatter ray included front of lead glass for patients within control room of computed tomographic equipment room which is place where most of work by gradiographic personnel are carried out and is outside of entrance door for exit and entrance of patients and their guardians and at spot 100 cm off from isocenter at the time of scanning the object. The results : Work environment within computed tomography room which was installed and under operation by each hospital showed considerable difference depending on circumstances of pertinent hospitals and status of scatter ray was as follows. 1) From isocenter of computed tomographic equipment to lead glass for patients within control room average distance was 377 cm. At that time scatter ray showed diverse distribution from spot where no presence was detected to spot where about 100 mR/week was detected. But it met requirement of weekly tolerance $2.58{\times}10^{-5}\;C/kg$(100 mR/week). 2) From isocenter of computed tomographic equipment to outside of entrance door where patients and their guardians exit and enter was 439 cm in average, At that time scatter ray showed diverse distribution from spot where almost no presence was detected to spot with different level but in most of cases it satisfied requirement of weekly tolerance of $2.58{\times}10^{-6}\;C/kg$(100 mR/week). 3) At the time of scanning object amount of scatter ray at spot with 100 cm distance from isocenter showed considerable difference depending on equipments. Conclusion : Use of computed tomographic equipment as one for generation of radiation for diagnosis is increasing daily. Compared to other general X-ray photographing field of diagnosis is very high but there is a high possibility of exposure to radiation and scatter ray. To be free from scatter ray at computed tomographic equipment room even by slight degree it is essential to secure sufficient space and more effort should be exerted for development of variety of skills to enable maximum photographic image at minimum cost.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1555-1565
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• 2018

Detection of subtle ground deformation of volcanoes plays an important role in evaluating the risk and possibility of volcanic eruptions. Ground-fixed observation equipment is difficult to maintain and cost-inefficient. In contrast, satellite remote sensing can regularly monitor at low cost. In this paper, following the study of Chadwick et al. (2006), which applied the interferometric SAR (InSAR) technique to the Sierra Negra volcano, Galapagos. In order to investigate the deformation of the volcano before 2005 eruption, the recent activities of this volcano were analyzed using Sentinel-1, the latest SAR satellite. We obtained the descending mode Sentinel-1A SAR data from January 2017 to January 2018, applied the Persistent Scatter InSAR, and estimated the depth and expansion quantity of magma in recent years through the Mogi model. As a result, it was confirmed that the activity pattern of volcano prior to the eruption in June 2018 was similar to the pattern before the eruption in 2005 and was successful in estimating the depth and expansion amount. The results of this study suggest that satellite SAR can characterize the activity patterns of volcano and can be possibly used for early monitoring of volcanic eruption.

• Korean Journal of Ichthyology
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• v.12 no.4
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• pp.236-243
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• 2000

The purpose of present the study was to describe the spawning behavior and early life history of the grass puffer, Takifugu niphobles. The grass puffer was caught at the spawning ground on the coast Dolsan, Korea from May to the 1998. Artificial fertilization was carried out to get fertilied eggs. Spawning season was from the end of May to the beginning of July on the coast of the Dolsan, Korea. Form 2~6 days before the spring tide the aduct males and females began to aggregate in the shore water, and they spawned in the upper part of intertidal zone exposed to air among pebble stone. The fertilized eggs were demersal, transparent and spherical in shape, and its diameter were 0.87~0.95 mm with several oil globules of 0.0014~0.0540 mm. Hatching began about 146 hours after fertilization under water temperature $21.2{\sim}22.3^{\circ}C$. The newly-hatched larva was 2.02~2.24 mm in total length (TL, mean: 2.14 mm), with 22~24(8~9+14~15) myotomes, and mouth and anus was not yet open. In 3 days after hatching it was measured 2.64~2.93 mm in TL (mean: 2.76 mm), and yolk sac was completely absorbed and transformed to postlarval stage. In 15 days after hatching it was measured 4.43~4.82mm in TL (mean: 4.59mm), and the caudal notochord flexion started. The larvae reached the juvenile stage in 28 days after hatching and attained 7.55~7.65mm in TL (mean: 7.60mm), and all fin-rays were formed.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.227-236
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• 2005

Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.512-512
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• 2016

우리나라의 다양한 수계에서는 배스로 대표되는 외래어종의 유입에 따른 심각한 생태계 교란이 발생하고 있다. 외래어종은 활발한 먹이활동 및 영역다툼을 통해 우리나라 고유종의 섭취 및 경쟁 우위에 위치하고 있다는 것이 많은 보도를 통해 발표되었다. 본 연구에서는 외래어종 중 배스(Large mouth bass)에 초점을 두고 동계 및 춘계의 서식처 특성을 살펴본다. 다양한 수계 중 갇혀있는 시스템으로 간주할 수 있는 농업용 저수지에 초점을 맞추고 현장조사를 실시한다. 하지만 현장조사 중 일부는 강과 같이 열린 서식처 공간도 포함하고 있다. 본 연구는 배스가 동면을 하지 않는 대신 수온에 큰 영향을 받으며 저수온기의 서식활동을 지속한다는 가정 하에 수온과 배스가 활동하는 영역의 상관성을 이해하고자 하였다. 조사는 국내 4개 지점 이상에서 이루어졌으며 수심 20 m 정도의 깊은 저수지에서부터 하수종말처리장에서 처리수가 유입되는 도시형 하천까지 포함한다. 이 중 수심 20 m 정도의 농업용 저수지에서는 7회 이상의 정밀 조사를 수행하여 수심별, 수온별 배스의 서식특성을 이해할 수 있도록 집중조사를 실시하였다. 현장조사 결과 배스는 $1-2^{\circ}C$의 수온차에도 민감하게 반응하며 서식처를 형성한다는 사실을 알 수 있다. 수온의 평면적 분포는 서식처의 형성에 많은 영향을 주는 것으로 판단되며 수온 안정기인 동계의 경우는 수온 종분포에 따라 군락을 형성하며 서식층을 결정한다는 점도 유추된다. 4월 중순 이후의 춘계는 배스의 산란기로 종확산에 큰 영향을 미치는 가장 중요한 시기이다. 이 시기 이후 하계에는 다시 부화한 개체가 독립적으로 서식처를 이동하는 또다른 종확산의 시기이다. 따라서 계절별에 따른 보다 면밀하고 지속적인 조사를 통해 4계절 순환에 따른 배스의 서식 특성 변화를 조사하는 과정이 필수적으로 이루어져야 한다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.67-68
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• 2001

우리 나라가 위치한 동북아 지역은 급속한 산업 및 경제활동 증가로 세계의 주요 오염 지역으로 대두되고 있다. 특히, 중위도 편서풍대 위치한 우리 나라는 주로 3월과 4월 황사의 영향을 받고 있다. 사막에서 발생한 모래먼지는 시정을 악화시키며 이들 중 미세한 입자(0.1~10$\mu\textrm{m}$)는 산란과 흡수를 통하여 대기의 복사평형과 기후변화에 커다란 영향을 미칠 수 있다(Carlson, 1980; Duce,1980; Shaw,1980). 이러한 현상은 주로 대기 중의 미세 입자의 광산란에 기인되는 것으로 도시 지역의 에어로졸의 분포 및 화학적인 성분과 밀접한 관계를 가진다. (중략)

• Journal of Ginseng Research
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• v.13 no.1
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• pp.119-122
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• 1989

phenological study on the oviposition, emergence, and flight activity of the African mole cricket adult has been made to obtain basic information for management of pest populations in ginseng fields. The flight activity, as monitored by the blarklight trap, seemed to be initiated depending on the sunset time and lasted about 2-2.5 hours. The trap data (1984-1988) showed that the adult flight of the species occurred twice a year, from early May to late June(Spring flight) and from late August to mid October(Fall flight) during which usually more crickets were trapped than during the former period. The number of females trapped was greater than that of males regardless to the flight period, i.e., females comprised 72.2%, 83.9%, and 73.3% of the total catches in 1984, 1985, and 1986, respectively. Adults emerged from late August to mid October and laid eggs from mid May to mid July the next year, indicating that the spring and fall flights correspond to the oviposition and emergence period, respectively.

• Journal of Astronomy and Space Sciences
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• v.9 no.1
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• pp.52-68
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• 1992

The ionosphere in accordance with solar activity can affect the transmission of radio waves. The effect of the ionosphere on the radio wave propagation are scattering of radio waves, attenuation, angle error, ranging error, and time delay. The present study is based on the Korean ionospheirc data obtained at the AnYang Radio Research Laboratory from January 1985 through October 1989. The data are analyzed to show the daily and the annual variations of the ionosphere. The data are also used to simulate the density distribution of the Korean ionosphere following the Chapman law.