• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.830-837
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• 2010

Since it started the researches on a maglev train on 1960, Germany and Japan arrived to putting to practical use level and accomplished most tests from their test-line. Korea is in progress the preparation for a practical use of low-speed maglev train in 110 [km/h] class and Korea Railroad Research Institute(KRRI) is in progress of a research about core technology of maglev system for high-speed tube train of 700 [km/h] class. In this paper, authors suggest an effective design method of Linear Synchronous Motor(LSM) for high-speed tube train of 700 [km/h] class which has a wound type electro-magnet. Then, authors calculate a variety of properties by changing speed of the LSM model which is designed by a method based on some theoretical equations. Then, authors verify the validity of the method based on some theoretical equations through a verification of property values by Finite Element Method(FEM) analysis method. Finally, in order to design a shape of pole-shoe part of LSM electro-magnet which is hard to design with a basic design method, authors analyze a transition of property values by changing a pole-shoe width and current of the electro-magnet through an analytical method by FEM.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.79-88
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• 2015

In this paper, it is investigated that the limitation due to the asymmetry of optical power and chromatic dispersion with respect to optical phase conjugator (OPC) for compensating optical signal distortion in WDM system is overcomed by using OPC position offset and optimal dispersion coefficients of fiber sections, which depend on OPC position offset. It is confirmed that overall WDM channels are efficiently compensated by applying the optimal parameter values obtained from the proposed method into 24 channels ${\times}40$ Gbps WDM system with non zero - dispersion shifted fiber (NZ-DSF) of 1, 000 km, such as power penalties of inter-channel are reduce to almost 3.5 dB from the infinite value. It is also confirmed that the flexible design of WDM system with OPC is possible by using the optimal parameters, in which OPC is placed at ${\pm}15km$ from 500 km for efficiently compensating overall channels. Thus, the methods proposed in this research will be expected to alternate with the method of making a symmetrical distribution of power and local dispersion in real optical link which generates a serious problem if it was not made but it is the condition in the case of applying the OPC into multi-channels WDM system.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.151-156
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• 2013

The experiment was done on cars travelling at the speeds of 20km/h, 60km/h and 100km/h using the performance testing mode for chassis dynamometer. In this experiment, the relativity between the secondary waveform coming from ignition coil and exhaust emissions were measured in case of cars with failures, in oxygen sensor, spark plugs. The following results obtained by analysis of the relativity between the secondary waveform and exhaust emissions. 1) When the oxygen sensor is failure, the average value of CO emission measured was 6.8 times higher than the standard CO emission value and the average value of HC emission measured was 2.3 times higher than the standard emission level. 2) When engine parts are in failure, more fuel enters the cylinder due to longer opening duration of injector, and it tended to make CO and HC emission values increase. 3) Combustion duration, the shape of flame propagation during spark line, and the size of the discharge-induced energy were the three main elements that directly cause variations in CO and HC emission values.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.772-776
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• 2007

In order to study the role of residue in the active site of glutathione S-transferase (GST), Arg13 residue in human GST P1-1 was replaced with alanine, lysine and leucine by site-directed mutagenesis to obtain mutants R13A, R13K and R13L. These three mutant enzymes were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized GSH. Mutation of Arg13 into Ala caused a substantial reduction of the specific activity by 10-fold. Km GSH, Km DCNB and Km EPNP values of R13A were approximately 2-3 fold larger than those of the wild type. Mutation of Arg13 into Ala also significantly affected I50 values of S-methyl-GSH that compete with GSH and ethacrynic acid, an electrophilic substrate-like compound. These results appeared that the substitution of Arg13 with Ala resulted in significant structural change of the active site. Mutation of Arg13 into Leu reduced the catalytic activity by approximately 2-fold, whereas substitution by Lys scarcely affected the activity, indicating the significance of a positively charged residue at position 13. Therefore, arginine 13 participates in catalytic activity as mainly involved in the construction of the proper electrostatic field and conformation of the active site in human GST P1-1.

• 미생물학회지
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• 제30권2호
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• pp.88-95
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• 1992

유전공학 기법으로 번형시킨 Km' plasmid 들의 전이를 30.deg.C 의 Luris-Bertani broth 에서 실시하였으며, 그 전이 빈도에 대한 donor 와 recipient 의 균주와 함께 pH 의 영향을 연구하였다. GEM 균주들과 NI 균주의 Km'plasmid 의 전이빈도는 recipient 가 MTI 일 경우 pH 7 에서 약 $10^{-5}$ 로 비슷하였으나 CS 균주인 DKC601 에서는 Km'plasmid 의 전이빈도가 $2.2 * 10^{-7}$ 로 훨씬 떨어졌다. 그리고 recipient 가 lab. strain (E. coli HB101) 인 경우에도 Km'plasmid 의 전이경향은 GEM 균주들과 NI 균주사이에 큰차이가 없었다. 또 어느 균주의 경우에나 pH 7 일 때의 전이 빈도가 $10^{-5}$ 정도로 가장 높게 나타났으며, pH 5 와 pH 9 에서는 그보다 조금 떨어졌다. 그러나 E. coli C600을 host 로 하여 제조한 CS 균주(DKC601)에서는 Km'plasmid 의 전이 빈도가 다른 GEM 균주들에 비하여 $10^{2}$ $-10^{3}$ 배 낮았으며 pH 4와 9 에서 6 시간의 conjugation 후에도 전이가 전혀 일어나지 않았다. Conjugant 에서의 plasmid의 재배열은 lab, strain 을 recipient 로 했을 경우에는 별로 없었지만, NI 균주를 recipient 로 했을 경우에 많이 나타났으며, 특히 donor 가 NI 균주보다 GEM 균주인 경우에 더욱 다양하였다. 그러나 pH 에 따른 타이는 그렇게 크지 않았다.

• Journal of Radiation Protection and Research
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• 제27권1호
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• pp.11-19
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• 2002

1998년부터 1999년까지 대전지역 대기부유진, 강수 및 낙진 중 $^7Be$ and $^{137}Cs$ 방사능 농도의 계절적 변화를 검토하였다. 대기부유진, 강수 및 낙진중 $^7Be$의 연평균 농도범위는 각각 $3.80{\sim}4.29 mBq\;m^{-3},\;1.25{\sim}1.67 Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$였다. 한편 대기부유진, 강수 및 낙진 중 $^{137}Cs$ 연평균 농도범위는 $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66\;mBq\;l^{-1}$ 및 $0.036{\sim}0.0455\;MBq\;km^{-2}$ 범위였다. 대기부유진 및 낙진 중 $^7Be$ and $^{137}Cs$ 농도는 낙진량이 많은 봄과 가을철에 높은 농도를 나타내었으며, 강수 중 $^7Be$ and $^{137}Cs$ 농도는 타 계절에 비해 강수량이 많은 여름철에 비교적 낮은 농도를 나타내었다. 한편 낙진과 강수에 의한 $^7Be$ and $^{137}Cs$의 연평균 총 침적량은 각각 $80.7{\sim}137 MBq\;km^{-2}$ 및 $0.059{\sim}0.060MBq\;km^{-2}$ 범위였으며, $^7Be$의 총 침적량중 약 80% 이상이 강우에 의해 침적되는 반면, $^{137}Cs$은 약 60% 정도가 낙진에 의해 침적되는 것을 알 수 있었다.

• 지질공학
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• 제18권2호
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• pp.185-190
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• 2008

이천온천원보호지구에는 9개의 온천공이 개발되어 있다. MRD-2 온천공이 996 m 심도까지 추가 굴착되기 이전의 온천공들의 굴착 심도는 166-294 m 범위였으며, 지하수면은 지표로부터 약 50m 정도 하부에 위치하였다. 이들 온천공에서 지표 온도와 공저온도를 이용한 연구지역의 지온경사는 최고 $64^{\circ}C/km$ (SB-2 온천공), 최저 $45^{\circ}C/km$ (SB-1 온천공), 평균 $54.28^{\circ}C/km$로 산정되었다. 그러나 심부까지 추가 굴착된 MRD-2 온천공을 관찰한 결과, 연구지역은 지표로부터 720 m 심도 이내 범위의 암반 균열계에 의해 매우 심한 열적 교란상태를 겪고 있는 것으로 나타났다. 이에 반하여, 심도 720 m 이하의 심부지역에서는 지하수의 유동이 존재하지 않는 것으로 관찰되었다. 따라서 연구지역의 지온경사는 열적으로 안정된 720 m 이하의 심도 구간 자료를 이용하여 $33^{\circ}C/km$로 재산정 되었으며, 이 값이 연구지역인 이천온천원지구에서의 합리적인 지온경사로 해석된다. 양수시험시 측정된 용출온도 $36^{\circ}C$는 지표하 720 m 심도에서의 온도 검층 결과와 일치되어 이 지점이 지하수 유동 및 열적 교란의 하부 경계가 되고 있음을 뒷받침하고 있다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.61-64
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• 2003

This study attempts to analyze both the mis-closures between triangulation points of 3 and 4 glade and permanent sites data, and accuracy of according as change the number of utilized GPS permanent sites and base lines for improvement of the accuracy in GPS surveying using permanent sites data. The result of this study show that the mis-closure between the two points and Jeonju/Chungju/Sangju/Daegu stations of NGI(National Geography Institute) are 0.0051 m, 0.0361 m, 0.0039 m and 0.0198 m respectively. It indicated that the mis-closures were less than the allowed values in the primary/secondary control point specification for GPS surveying, a mis-closure less than 30 mm for the distance less than 30 km and a mis-closure less than 1 PPM${\times}$D(km) for the distance greater than 30 km. Jinan 11 of actual surveying point for the base line 21.4911 km in Jeonju permanent site and 87.8156 km in Sangju permanent site, northing and easting for planimetric errors of Jinan 11 are 0.0120 m and 0.0113 m, northing and easting for planimetric errors of Jinan 12 are 0.0122 m and 0.0115 m.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.625-629
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• 2014

For the purpose of the acoustic performance evaluation of noise reduction device(NRD) installed at the top of noise barrier for further decreasing of noise level of 400km/h class high-speed railroad(HEMU), the acoustic performance test method using speaker instead of really running railway vehicle was suggested in this paper. For this, noise source location and frequency spectrum of HEMU was analyzed through the field noise test. These data were used for the determination of speaker's installation positions and frequency correction values applied to the speaker noise source. And, 400 meters long NRD was installed at the site where HEMU will be running at a speed of 400km/h. Finally, the outdoor speaker test with and without NRD showed that this NRD could decrease noise level even more than 3dB(A). In the future, the acoustic performance results of NRD conducted with speaker test will be compared with that of field test for HEMU running at a speed of 400km/h.

• Journal of Astronomy and Space Sciences
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• 제18권3호
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• pp.191-208
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• 2001

We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be $1.77{\times}10^{-15}km^{-2}yr^{-1}$, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) ($5.6{\pm}2.8{\times}10^{-15}km^{-2}yr^{-1}$. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.