• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.118-118
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• 2012

Cryopump는 반도체 임플란타 공정, OLED분야, 신소재 개발, 표면분석 및 처리, 의료분야, 입자가속기, 핵융합 등 다양한 진공분야에 응용되는 고진공용 극저온펌프이다. 특히 향후로의 산업구조는 디스플레이, 반도체, IT 산업분야로 집중 재편될 것이기에, 이에 따른 핵심제조장비인 고진공 펌프의 수요가 급증할 것으로 판단된다. 그리고 이를 위한 핵심부품과 장비들의 국산화가 시급한 실정이다. 기술적인 측면에서 보자면 GVT는 미국의 Varian과 일본Ebara의 Cryopump 제조기술을 원천으로 한 회사로써 현재는 국내 유일의 G-M 냉동기와 Cryopump 제조기술을 보유한 업체이다. 그리고 최근 오랫동안 정체되었던 관련 기술을 발전시켜 최적화된 한국형 G-M 냉동기 및 이를 장착한 다양한 사이즈의 고성능 Cryopump를 출시하게 되었다. 가장 큰 수확은 Cryopump의 성능을 크게 향상시켰으며 무엇보다 고객맞춤형으로 디자인할 수 있을 정도의 기술력을 확보하게 되었다는 점이다. Cryopump의 성능은 장착되는 Cryocooler (G-M냉동기)의 성능과 밀접한 관련이 있기 때문에 일차로 Cryocooler의 성능을 개선하고 이차로 이를 장착한 Cryopump의 성능을 개선하였다. 본 연구는 일차로 진행된 HP Series 2단 Cryocooler 4가지 모델 중 가장 범용인 HPM 모델과 HPS모델에 대한 제작과 성능시험에 관한 것이다. 이는 각각 기존의 ICP Series 펌프에 장착되던 Expander 535 모델 및 Expander 855 모델에 대한 설계 최적화의 결과물로써 내용은 Cryocooler에 대한 'Typical Performance Test(1st STG와 2nd STG의 온도가 각각의 Stage에 인가되는 Heat Load에 의해 그물망 형태의 그래프가 되도록 수행하는 시험법)'의 절차를 따라 수행되었다. HPM Cryocooler의 성능은 2nd STG Temp. 20K와 1st STG Temp. 80K를 Heat Load기준으로 하였을 경우, 각각 8.2W, 55.0W의 성능을 나타내었고 HPS Cryocooler의 성능은 2nd STG Temp. 20K 와 1st STG Temp. 72K를 Heat Load기준으로 하였을 경우, 각각 14.0W, 90.0W의 성능을 나타내었다. 1st STG Temp.를 72K로 정한 이유는 Power Supply의 용량 한계로 인해 90W이상의 Heat Load를 인가할 수 없었기 때문이다. 만약 성능 그래프의 경향성을 고려하여 1st STG Temp. 80K로 가정한다면, 각각 약 13W, 100W 정도의 성능을 가질 것으로 추정된다. 단, 본 시험에 사용된 Compressor는 GVT의 HC80Plus 모델로 내부에는 Helium용 5HP급 Scroll Type의 Compressor가 장착되어 있으며, 봉입압력 250Psig에 저압 100Psig기준, 65scfm의 유량을 가지는 압축기이다. 압축기와 Cryocooler의 조합은 1:1이었고 시험방법은 Cryocooler에 대한 GVT 자체규정에 따라 진행되었으며 밤과 낮 및 공장전체의 부하변동에 따른 냉각수 온도변화에 따른 펌프의 성능변화는 고려되지 않았다.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.76-86
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• 2008

The seasonal variations of primary production were investigated by phyto-PAM chlorophyll fluorometry as well as classical methods (standing crops of phytoplanktons and chlorophyll ${\alpha}$) in the Beopsu Marsh, Haman-gun, Gyeongsangnam-do. The amounts of turbidity, SS, T-N, T-P, BOD, COD, Ca$^{2+}$ and Cl$^-$ were the highest at the station 3, where located in flowout site of wastewater treated by the filtration plants. The water quality was the third level by the standard of BOD and COD. The amount of chlorophyll a (268.8 mg L$^{-1}$) was the highest at the station 2 in April because the cell density (2,677 cells mL$^{-1}$) of Micractinium pusillum increased suddenly from February (180 cells mL$^{-1}$). The patterns of primary production of phytoplankton by phyto-PAM chlorophyll fluorometry were fallen in with those of standing crops and chlorophyll a of phyto-planktons. The primary production was varied according to stations and seasons. The water environments of the Beopsu Marsh as a natural mounument should be under the control of a regular examination in order to preserve the ecosystem.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.133-138
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• 2003

The data on outbreaks of puffer fish poisoning during 1991 to 2002 in Korea were gathered from press reports, and characterized information collected. During the period, a total of 32 outbreaks of puffer fish poisoning was reported. These outbreaks caused 111 persons to become poisoning, among the cases 30 persons were fatal. The mean case fatality rate was 27.0%, and most of deaths (93.3%) were the male of above 29 years old. Patient number of below 4 persons per a poisoning accident occupied 75.0% of total outbreaks; 65.8% of total cases; and 66.7% of total deaths) was occurred in the months, November through January. Most of puffer fish poisoning (75.0% of total outbreaks; 68.5% of total cases; and 73.3% of total deaths) were found along the south coastal area of Korea, including Busan, Gyeongsangnam-do, Jeollanam-do and Jeju-do. Over than 80% of puffer fish poisoning outbreaks occurred at fishing boat and home where privately made food was cause, and outbreaks in restaurants accounted for 15.6%. Most commonly implicated foods were Guk, boiled soup with puffer fish meat and spices.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.194-201
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• 2014

To elucidate which climate factors and what periods affect the time of breeding migration of Gori salamanders (Hynobius yangi), we have investigated relationships between the 5-years breeding monitoring data from 2006 to 2010 which had obtained in both natural and translocated breeding sites at Bongdae mountain, Gijang-gun, Busan-si and the matched climate data obtained from the weather station, approximately 25 km apart from the sites. Mean average and mean lowest temperatures during one month before the first breeding migration were related with the time of first female migration in the translocated site. Mean temperature variation and mean precipitation during 60~120 days before the first breeding migration affected the time of 30% male appearance at the natural site and the time of 30% female appearance at both natural and translocated sites. Climate factors were more closely related with female appearance than male and at the translocated site than at the natural site. Our results show that changes in mean temperature variation and mean precipitation rather than mean average temperature might more significantly affect the breeding migration of salamanders, female breeding migration is more closely related with climate factors, and the salamanders translocated could be more affected by climate changes than those in natural populations.

• Journal of the Korean association of regional geographers
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• v.5 no.2
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• pp.143-153
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• 1999

This study is analyzed the correlation between El-Nino and La-Nina and Korea's temperature and precipitation in summer and winter, and the results of this analysis are as follows: (1) The extraction of the occurrences of El-Nino reveals are 5, but La-Nina reveals 6 years. (2) The tendency of change of sea surface temperature around NINO.3 and that of or country are about the same, but the anomaly of Janggi and Pusan was much greater than that of Inchon. (3) The anomaly of sea surface temperature around NINO.3 and that of the temperature showed the similar changing tendency, the temperature of Korea has something to do with that of NINO.3sea surface temperature as the correlation of ground temperature with the temperature of sea surface showed 0.06. Anomaly warm winter has something to do with El-Nino because the temperature of our country was high when El-Nino phenomena appeared. But the precipitation over our country is not significant for La-Nina. (4) Temperature in El-Nino year is lower than normal in summer and higher than normal in winter. But precipitation is more in summer and winter of El-Nino year, but it is not significant of La-Nina year.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.109-120
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• 2007

The information on flowpath, storage, residence time, and interactions of water and carbon transport in a catchment is the prerequisite to the understanding and predicting of water and carbon cycling in the mountainous landscapes of Korea. In this paper, along with some up-to-date results, we present the principal methods that are currently used in HydroKorea and CarboKorea research to obtain such information. Various catchment hydrological processes have been examined on the basis of the water table fluctuations, the end-member mixing model, the cross correlation analysis, and cosmogenic radioactive isotope activity. In the Gwangneung catchment, the contribution of surface discharge was relatively large, and the changes in the amount, intensity and patterns of precipitation affected both the flowpath and the mean residence time of water. Particularly during the summer monsoon, changes in precipitation patterns and hydrological processes in the catchment influenced the carbon cycle such that the persistent precipitation increased the discharge of dissolved organic carbon (DOC) concentrated in the surface soil layer. The improved understanding of the hydrological processes presented in this report will enable a more realistic assessment of the effects of climate changes on the water resource management and on the carbon cycling in forest catchments.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.79-90
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• 1997

Monthly samples of surf zone fish at Taechon Beach were collected by a beach seine from June 1995 to May 1996, and analyzed for the species composition, abundance and community structure. Of 26 species identified, Favonigobius gymnauchen, Leiognathus nuchalis, Sillago japonica and Kareius bicoloratus predominated in abundance. In spring, the adults of resident species were dominated. A large number of juveniles of pelagic or demersal fish occupied the surf zone from summer to autumn. Fish numbers and biomass were low in winter. The species composition of the present study showed a similar seasonal trend to that obtained in 1984-85. However, demersal fish such as K. bicoloratus, Repomucenus lunatus, Johnius belengerii and Enedrias fangi, and L. nuchalis were increased, while pelagic fish such as Thrissa koreana, Sardinella zunasi and Konosirus punctatus were diminished. These changes seemed to be related to sedimentation of fine particles for demersal fish and subsequent increase in turbidity for pelagic fish after reclamation in the bay.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.473-481
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• 2012

Demand of Natural Gas (NG) consumption is continuously increasing by long service life and low environmental impact than other fossil fuels. Because of this reasons, Gas wells exploration and huge LNG plant construction project are being boosted world-widely. Especially, overseas NG pipe-line projects are emerging by considering safe and efficiency at the inter-country sections. At the same time, Korean contractors are being achieved to record-breaking performance at 2011's overseas construction market and 80% of new-record was attained from overseas plant construction projects. Nevertheless, Korean contractors are behind than overseas leading contractors by geographical distance from gas wells and concentrated demand for storage plant. In these reasons, this paper aims to develop the standardized business process model(BPM) for overseas NG pipe-line project at project planning phase to support the project entry. To this aim, first of all, extract the BPM through the broad literature and overseas construction market review and domestic/overseas pipe-line project analysis. Second, Test-bed was performed to confirm of practical applicability by 4 experts. And then 15 experts survey were performed to validate the usability and effectiveness of BPM for overseas NG pipe-line project. Consequently, if Korean contractors are using this BPM with their own know-how and experiences, it will be returned to more reasonable and rational references for decision making in overseas NG pipe-line project.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.2
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• pp.58-67
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• 1995

The paper describes the variation of magnetic fields caused by the operation of induction motors. The measuring system consists of the self-integrating magnetic field sensor, amplifier, and active integrator. From the calibration experiments, the frequency bandwidth of the magnetic field measuring system ranges from 20[Hz] to 300[kHz] and sensitivity is 0.234(mV/$\mu\textrm{T}$]. The magnetic fields generated under steady state and starting operations of duction motor are recorded by the proposed measuring system, and the fast Fourier transformation(FFT) of the measured data is performed to analyze the harmonic components. A single pulsed magnetic field is strongly caused by direct starting the induction motor, and its peak value is greater than 5 times as compared with the steady state value. The long transient duration and high intensity originates from the large inductance and dynamic characteristic of the induction motor, During the steady state operation of induction motor, subharmonics of magnetic field components, which depend on the pole number of induction motor, are observed. The lower order power-line harmonics can be inferred from the voltage flicker and current ripple which are derived from the torque fluctuation of induction motor. In the case of the induction motor drived by inverter, the harmonics of magnetic field are much more than those caused by direct starting method and are found generally to increase with decreasing the driving frequency.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.369-376
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• 2003

In this paper, a nonlinear structural analysis for the composite structure composed of the spent nuclear fuel disposal canister and the 50㎝ thick bentonite buffer is carried out to predict the collapse of the canister while the horizontal symmetric sudden rock movement of 10㎝ is applied on the composite structure. This sudden rock movement is anticipated by the earthquake etc. at a deep underground. Elastoplastic material model is adopted. Drucket-Prager yield criterion is used for the material yield prediction of the bentonite buffer and von-Mises yield criterion is used for the material yield prediction of the canister(cast iron, copper). Analysis results show that even though very large deformations occur beyond the yield point in the bentonite buffet, the canister structure still endures elastic small strains and stresses below the yield strength. Hence, the 50㎝ thick bentonite buffet can protect the canister safely against the 10㎝ sudden rock movement by earthquake etc.. Analysis results also show that bending deformations occur in the canister structure due to the shear deformation of the bentonite buffer.