Ray tracing simulation of SCOTS test for GMT secondary mirror

김기원,김성환,김영수,Kim, Ki-Won,Kim, Sug-Whan,Kim, Young-Soo 한국천문학회 2012 天文學會報 Vol.37 No.2

We present SCOTS test simulation for on axis segment of the GMT secondary mirror that is ellipsoidal shape surface of 1.064m in diameter, 4.166747m in radius of curvature, -0.7154 in conic constant and $18.023{\mu}m$ P-V in asphericity. SCOTS test comprises a screen(diffusing sinusoidal fringe source), test surface(GMT secondary mirror), and a camera(CCD detector). We report ray tracing simulation result that is distorted sinusoidal fringe pattern detected at the camera. This simulation is to be used for analysis of experimental design, sensitivity from uncertainty, errors on fabrication and design.

금강비 측정 교구 개발 및 체험수학활동

김기원,도혜경,Kim, Ki-Won,Do, Hye-Kyung 영남수학회 2010 East Asian mathematical journal Vol.26 No.2

In this study we develop mathematical tools for measuring the Geumgang Ratio and we call them Geumgang Ratio Calipers. Also we show a teaching method for ratio through experimental mathematics. With Geumgang Ratio Calipers students measure the Geumgang Ratio in their bodies, materials for everyday life and the Sukgulam. Through this activity, students obtained an interest in mathematics and gained a positive attitude for mathematics.

이앙전작 청예작물 재배에 관한 연구 1 . 이앙전작 청예 옥수수의 예취 시기가 후작 ( 수도작 ) 의 생육 및 수량에 미치는 영향

김기원,조헌조,이을희 ( Ki Won Kim,Cho Hyen Cho,Ell Hee Lee ) 한국축산학회 1979 한국축산학회지 Vol.21 No.4

This experiment was carried out to investigate the effect of the cutting stages on the yield of soiling corn (previous crop), and the characteristics and the yield of paddy rice (following crop) to set up the reasonable crop rotation system on following paddy field in she southern area. The results obtained were as follows: 1. The height of soiling corn was higher as the cutting stage was prolonged. 2. The highest yield (7,445 ㎏/10a) was in the plot cut on 23, June among cutting stages. The yield of the plot cut on 3, June was less then three plots cut 13 June, 23 June and 30 June, `There was no significant differences between two plots cut on 23 June and 30 June. 3. The highest dry matter yield(1388.91 ㎏/ l0a) was in the plot cut on 30 June of all. There were significant differences (p$lt;0.01) on the dry matter yield of each plot. It was increased as the growth stage was prolonged. 4. Rice growth (Milyang 15), following crop transplanted on 23 June, was no difference as compared with that of the common cultivation transplanted on 18 June. However, the same crop transplanted after June 23 was not grown well. 5. The highest rice yield (570.36㎏/l0a) was in the plot transplanted on 13 June the plot transplanted on 3 June produced more yield than two plots transplanted on 23 June and 18 June and(common cultivation)and the plots transplanted on 23 June and after 18 June were less than others in the rice yield. Therefore, it may be concluded that there was no difficulties on the production and the growth of rice cultivation after soiling corn cultivation when rice paddy was transplanted before 23 June in the southern area.

율무의 사료적 가치에 관한 연구 1 . 파종시기가 율무의 생육 및 조곡생산에 미치는 영향

김기원,강봉태,문승식 ( Ki Won Kim,Bong Tae Kang,Sueng Sik Moon ) 한국축산학회 1976 한국축산학회지 Vol.18 No.1

This experiment was carried out to investigate the seeding period on the characteristics and grain production of Coix lacryma L. The results obtained are as follows: 1. The height of plants, leaf-size and number of tiller were higher in the treatment sown from late March to late April than in the treatment sown in May. 2. The height of plant was decreased as the seeding period progressed. However the number of seed per plant was increased as the seeding period progressed. 3. A highly (p$lt;0.001) significant difference was found in the production of grain according to the seeding periods. The treatment sown March 20 and April 8 produced 709.3㎏ and 681㎏ of grain per 10a, respectively and produced the highest amount among all the treatments. However the production of grain in the, treatments sown after May was decreased. 4. Average rice cleaning of Coix lachryma L. was 40%. 5. According to this experiment, the moderate seeding period of Coix lacryma L. was from late May to late April. 6. The crude protein of grain of Coix lacryma L. was 16.47%. Therefore it may be concluded that Coix lacryma L. can be used as a feed and food.

한국 음악 속의 수학

김기원,안선필,Kim Ki-Won,Ahn Sun-Phill 한국수학사학회 2004 Journal for history of mathematics Vol.17 No.4

수학과 음악은 그 표현 방법이 아주 다른 학문이지만, 오래 전부터 수학과 음악이 관련이 있음을 이야기 해오고 있다. 이 논문에서는 수학과 한국 음악의 관계를 고찰해보고 수학 교육에의 활용 방안을 모색해 본다. Even though mathematics and music play very different roles in our society, they are closely related to each other. In this paper, we studies relations between mathematics and Korean traditional music, and give some ideas to use such relations in mathematics education.

플래시버트 용접과 연속열간압연법으로 제조된 철근의 기계적 성질과 미세조직에 미치는 합금원소의 영향

김기원,조승재,강정윤,Kim, Ki-Won,Cho, Seung-Jae,Kang, Chung-Yum 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.3

Flash butt welding is applied in many industries. New technology was developed recently for joining billets which called "EBROS (Endless Bar Rolling System)". After reheating billets in furnace, two billets were joined using flash butt welding. The objective of this study was to investigate the effect of alloying elements on mechanical properties of flash butt welded zone of hot rolled steel bar. The tensile properties on welded zone of Fe-Mn steel and Fe-Mn-V steel were dropped as compared with non-welded zone. Fe-Mn-Nb steel was opposed to the former. It was found that the white band at the welded zone had high ferrite volume fraction and large ferrite grain size. The vertical white band between flash butt welded billets was transformed into an arrowhead it of steel bar. According to this band, softening has been appeared. There was a interesting phenomenon with HAZ of Fe-Mn-Nb Steel, 40nm scale of particles were observed and hardness of HAZ was higher than non-welded zone.

율무의 재배법에 관한 연구 1 . 시비 적량 시험

김기원,강봉태,문점동 ( Ki Won Kim,Bong Tae Kang,Jeam Dong Moon ) 한국축산학회 1976 한국축산학회지 Vol.18 No.2

This experiment was carried out to investigate the amount of fertilizer application in Coix lacryma L. by the cutting stage. The results obtained were as follows; 1. The grass length was not affected by the amount of fertilizer application in the 1st and 2nd cutting stage. However in the 3rd cutting stage the grass length was significantly (P$lt;0.05) affected by the amount of fertilizer application. 2. The yield significantly (P$lt;0.01) increased as the fertilizing level increased in the 1st and 2nd cutting stage, however, the yield in the 3rd and overall cutting stage was not affected by the amount of fertilizer application. However, treatment-Ⅱ, treatment-Ⅷ and treatment-Ⅸ which were plentiful of nitrogen, phosphorus and potassium produced more green grass than other treatments. 3. Therefore it may be. concluded that the moderate amount of fertilizer application in Coix lacryma L. which is cultivated for green forge was 14㎏ of nitrogen per 10a., 7.5㎏ of phosphorus per 10a. and 11㎏ of potassium per 10a.

이앙전작 청예작물 재배에 관한 연구 2 . 수도전 청예옥수수의 예취 시기가 초장 , 수량 , 일반조성분 및 토양의 pH , 유기질 함량에 미치는 영향

김기원,조헌조,김대성 ( Ki Won Kim,Hyen Cho Cho,Dae Sung Kim ) 한국축산학회 1979 한국축산학회지 Vol.21 No.6

To investigate the reasonable utilization method of paddy field in southern district ,this experiment was carried out to detect the effect of cutting stage on the grass height, yield and chemical composition of green crop cultivated in the paddy field which was idle and on the pH and organic matter of Soil. The results obtained were as follows. 1. Grass height of yellow corn cut on June 20 was 231.29㎝ on the green basis and highest among the treatments. Grass height of yellow corn cut on June 1 was 174.77㎝ on the green basis and shortest among the treatments. In the cutting stage, significant differences were found out between treatments (P$lt;0.05). However there were no difference between grass height of yellow corn cut on June 15 and June 20 on the green basis. 2. In the ratio of leaf to stem, leaf was generally higher than stem. However treatments cut on June 1 and June 20 have slightly less leaf than treatments cut on other cutting stage. 3. In the green yield, treatment cut on June 20 produced the highest yield (8969.33㎏ per l0a) among treatments. Treatment cut on June 1 produced the lowest yield(7296.67㎏ per l0a)among treatments. There were significant, differences (P$lt;0.05) between cutting stages in the green yield. Yield was increased as the cutting stage was late. 4. In the dry matter yield, treatment cut on June 1 produced the lowest yield(796.08㎏) and treatment cut on June 20 produced the highest yield among treatments. Dry matter yield was generally increased as the growth stage progressed. 5. In the chemical composition, treatment cut early was high in crude protein content and low in crude fiber content of soiling corn. However crude fiber content of soiling corn was increased as the growth stage progressed.. 6. pH of soil was higher in the field fertilized after than in the field fertilized before. pH of soil was progressively decreased as the cutting stage was prolonged and was lower than that of soil fertilized before. 7. In the organic matter content of soil, treatments cut on June 5 and June 10 were lower in organic matter content than before fertilization. Other treatments were similar to organic content of soil fertilized before. Therefore according to this experiment, it may be concluded that there were no influences on the cultivation of rice when soiling crop (corn) was cultivated in the paddy field before transplanting rice.

이앙전작 청예작물 재배에 관한 연구 3 . Silage 용 옥수수의 파종시기가 생육 , 수량 및 토양의 pH , 유기질함량에 미치는 영향

김기원,강봉태,이을희 ( Ki Won Kim,Bong Tea Kang,All Hee Lee ) 한국축산학회 1982 한국축산학회지 Vol.24 No.5

This experiment was conducted to investigate the effect of the seeding time of silage corn before transplanting rice on the growth, green yield, the PH and organic matter content of soil after cutting in southern regions. 1. The plant height of silage corn sowed from March 27 (88days for the period of vegetation) to April 1(83 days for the period of vegetation) was superior to that sowed after April 26(58 days for the period of vegetation) and there were significant differences (P $lt;0.01) among the seeding times. 2. In the seeding time, the earlier silage corn sowed, the higher the rate of stem to leaf was, but the later the silage corned sowed, the higher the rate of leaf to stem was. 3. In the fresh yield, the growth of silage corn sowed on March was superior to that sowed after the middle of April because of the long period of vegetation and it can be suggested that the period of vegetation increased the growth and yield of silage corn be apt to 68 to 88 days. 4. In the dry matter yield, there were significant differences (P $lt; 0.01) among the seeding times (the period of vegetation). 5. In the organic matter content of soil, the earlier the seeding time was, the less the organic matter content was, but that of soil sowed April 16 was similar to that after fertilization.

약용식물의 사료화에 관한 연구 1 . 우슬 ( Achranthes Japonica Nakai ) 의 사료적 가치

김기원,문점동 ( Ki Won Kim,Jean Dong Moon ) 한국축산학회 1981 한국축산학회지 Vol.23 No.3

To investigate the nutritive values of Achranthes Japonica Nakai this experiment was carried out for 1 year and 7 months from March, 1976 through October, 1977. Characteristics, yield and chemical composition of Achranthes Japonica Nakai by cutting stages were investigated. The results obtained were as follows; 1. Average plant height of Achranthes Japonica Nakai was 59.5㎝. The plant height at the 2 nd cutting stage was 69.5㎝ and was highest among the cutting stage. 2. Number of tiller of Achranthes Japonica Nakai increased as the cutting stage advanced and number of branch was Rightest at the 1st cutting stage. 3. Achranthes Japonica Nakai produced 4718㎏ of green forage per l0a and produced more yield at the 2nd cutting stage than at and other cutting stages. Dry matter yield of Achranthes Japonica Nakai was 757㎏ per 10a. 4. Crude protein content of Achranthes Japonica Nakai decreased and crude fiber content increased as the cutting stage progressed. The crude protein and crude fiber contents of AchranthesJaponica Nakai showed a great difference by the cutting stages. It may be concluded that Achranthes Japonica Nakai has a similar value compared with improved grasses on the yield and chemical composition, therefore, it could be developed as a forage resource.