마그네슘의 금속염화물 환원에 의한 초미립 TiCN 분말합성

이동원,김진천,김용진,김병기,Lee, Dong-Won,Kim, Jin-Chun,Kim, Yong-Jin,Kim, Byoung-Kee 한국분말야금학회 2009 한국분말재료학회지 (KPMI) Vol.16 No.2

The ultrafine titanium carbonitride particles ($TiC_{0.7}N_{0.3}$) below 100nm in mean size were successfully synthesized by Mg-thermal reduction process. The nanostructured sub-stoichiometric titanium carbide ($TiC_{0.7}$) particles were produced by the magnesium reduction at 1123K of gaseous $TiC_{l4}+xC_2Cl_4$ and the heat treatments in vacuum were performed for five hours to remove residual magnesium and magnesium chloride mixed with $TiC_{0.7}$. And final $TiC_{0.7}N_{0.3}$ phase was obtained by nitrification under normal $N_2$ gas at 1373K for 2 hrs. The purity of produced $TiC_{0.7}N_{0.3}$ particles was above 99.3% and the oxygen contents below 0.2 wt%. We investigated in particular the effects of the temperatures in vacuum treatment on the particle refinement of final product.

서양의 역사적인 지도제작법의 발달 과정과 수학적 지식의 상호 영향 관계를 통해 본 직교좌표계

이동원,Lee, Dong Won 한국수학사학회 2012 Journal for history of mathematics Vol.25 No.4

역사적인 지도제작법에 나타난 좌표계와 수학적 직교좌표계의 발전 과정을 비교하면서 위치를 표시하는 직교좌표계는 수학의 해석기하학과는 상관없이 인간 본연에 내재되어 있었던 공간지각능력의 일환으로 발전되어 왔음을 주장한다. 지도제작법의 발전이 해석기하학의 발명 전후 삼각함수, 로그, 기하학, 미적분학, 통계학 등 수학의 여러 분야와 상호 영향을 미치지만 원점의 표시나 음수 좌표의 사용과 같은 수학적 직교좌표계 자체에 대한 발전은 데카르트의 논문 발표 후 100여년 이상 지난 후에 이루어지는 점, 해석기하학을 발명하는데 공헌한 대부분의 수학자들이 당대의 문제 해결에 집중하면서 직교좌표계에 대한 수학적 설명없이 자연스럽게 사용하였던 점을 바탕으로 이런 결론을 얻는다. By comparing the development history of rectangular coordinate system in Cartography and Mathematics, we assert in this manuscript that the rectangular coordinate system is not so much related to analytic geometry but comes from the space perceiving ability inherent in human beings. We arrived at this conclusion by the followings: First, although the Cartography have much influenced to various area of Mathematics such as trigonometry, logarithm, Geometry, Calculus, Statistics, and so on, which were developed or progressed around the advent of analytic geometry, the mathematical coordinate system itself had not been completely developed in using the origin or negative axis until 100 years and more had passed since Descartes' publication. Second, almost mathematicians who contributed to the invention of rectangular coordinate system had not focused their studying on rectangular coordinate system instead they used it freely on solving mathematical problem.

기공실에서 발생되는 분진이 폐 조직에 미치는 악 영향

이동원,Lee, Dong-Won 대한치과기공학회 1985 대한치과기공학회지 Vol.7 No.1

3상 교류전원 LED 램프의 광 플리커

이동원,김병철,Lee, Dong Won,Kim, Byungcheul 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.4

This study describes that light flicker of LED lamp is improved by placing an AC-powered LED block in each phase of three-phase AC power. Rectified current is considered as an instantaneous luminous flux because the current flowing through the LED block is proportional to the amount of light emitted by the LED block. Percent flicker is calculated simply by modeling the rectified current flowing through the LED block to a triangular wave current. Percent flicker is 100% in single-phase AC powered LED lamp. Percent flicker of the same level as that in an incandescent lamp (6%~14%) is however, achieved if light emission starts before $40^{\circ}$ in each voltage phase of three-phase AC power.

심장과 호흡의 연결성을 이용한 감성인식 방법

이동원,박상인,황민철,Lee, Dong Won,Park, Sangin,Whang, Mincheol 한국감성과학회 2017 감성과학 Vol.20 No.3

Physiological responses have been measured to recognize emotion. Although physiological responses have been interrelated between organs, their connectivities have been less considered for emotion recognizing. The connectivities have been assumed to enhance emotion recognition. Specially, autonomic nervous system is physiologically modulated by the interrelated functioning. Therefore, this study has been tried to analyze connectivities between heart and respiration and to find the significantly connected variables for emotion recognition. The eighteen subjects(10 male, age $24.72{\pm}2.47$) participated in the experiment. The participants were asked to listen to predetermined sound stimuli (arousal, relaxation, negative, positive) for evoking emotion. The bio-signals of heart and respiration were measured according to sound stimuli. HRV (heart rate variability) and BRV (breathing rate variability) spectrum were obtained from spectrum analysis of ECG (electrocardiogram) and RSP (respiration). The synchronization of HRV and BRV spectrum was analyzed according to each emotion. Statistical significance of relationship between them was tested by one-way ANOVA. There were significant relation of synchronization between HRV and BRV spectrum (synchronization of HF: F(3, 68) = 3.605, p = 0.018, ${\eta}^2_p=0.1372$, synchronization of LF: F(3, 68) = 5.075, p = 0.003, ${\eta}^2_p=0.1823$). HF difference of synchronization between ECG and RSP has been able to classify arousal from relaxation (p = 0.008, d = 1.4274) and LF's has negative from positive (p = 0.002, d = 1.7377). Therefore, it was confirmed that the heart and respiration to recognize the dimensional emotion by connectivity. 감성을 인식하는데 있어 생리적 반응은 중요하다. 생리적 반응은 인체의 주요 기관들과 밀접한 관련이 있지만 감성을 인식하는데 연결성은 고려되지 않고 있다. 자율신경계는 감성과 밀접한 관련이 있는데, 심장과 폐와 같은 인체 내 주요 내장기관에 분포되어 기능적 상보작용을 통해 생리적 반응을 조절하기 때문이다. 따라서 본 연구는 심장과 호흡의 연결성을 분석하고 감성을 인식하는 중요한 연결 변수를 찾고자 하였다. 피험자 18명(남 10명, 평균 나이 $24.72{\pm}2.47$)은 소리 자극을 이용한 감성 유발 실험에 참여하였고 심전도와 호흡 데이터를 측정하였다. 수집된 심장과 호흡 데이터는 스펙트럼 분석을 이용하여 HRV와 BRV spectrum을 구하였고, 감성에 따른 HRV와 BRV spectrum의 동기화 차이를 일원배치분산분석을 통해 통계적 유의성을 확인하였다. Tukey 검증 결과, arousal-relaxation은 HF 대역에서 심전도와 호흡의 동기화 차이로 인식 가능하였고(p = 0.008, d = 1.4274), negative-positive는 LF 대역에서 인식이 가능하였다(p = 0.002, d = 1.7377). 본 연구 결과로 심장과 호흡의 연결성을 통해 차원적 감성을 정량적으로 평가할 수 있음을 확인하였고, 복합적인 원인으로 발현되는 감성을 인식하는데 생리적 반응들의 연결성 변수의 활용도가 높을 것으로 기대된다.

무한강하법을 이용한 증명지도의 연구

이동원,김부윤,정영우,Lee, Dong Won,Kim, Boo Yoon,Chung, Young Woo 영남수학회 2016 East Asian mathematical journal Vol.32 No.2

There are three subjects in the study. First, after investigating the development process of the method of infinite descent and the reduction to absurdity, we prove them to be equivalent each other. Second, we apply the method of infinite descent to some problems in textbook and compare it with the reduction to absurdity. Finally, we discuss on teaching proofs with the method of infinite descent.

화학기상응축법으로 제조된 철 나노분말의 산화저항에 관한 연구

이동원,유지훈,배정현,장태석,김병기,Lee Dong-Won,Yu Ji-Hun,Bae Jeoung-Hyun,Jang Tae-Suk,Kim Byoung-Kee 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.3

In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below $130^{\circ}C$ in air was $10\~40$ times higher than that of the air- passivated particles.

과배란 처치시 우세난포 조절에 의한 한우 수정란 생산성 향상에 관한 연구 II. 과배란 처치 시기에 따른 난소반응

이동원,이병천,황우석,Lee, Dong-won,Lee, Byeong-chun,Hwang, Woo-suk 대한수의학회 2000 大韓獸醫學會誌 Vol.40 No.4

This study was investigated the ovarian response following superovulation treatment at different day of diestrus. The criterion for the presence or absence of a dominant follicle based on their morphological examination. Dominant follicle was puntured 48 hrs before the oneset of superovulation treatment by ultrasonography guided aspiration needle. Superovulation was induced by subcutaneous administration of FSH twice a day for 4 day in a decreasing regimen. There was no significant different between presence of dominont follicle and progesterone concentration/diameter of corpus luteum in HanWoo. Number of corpus luteum of donor after superovulation treatment was not significantly different in FSH administration at day 9, 11 and day 13 of estrus($14.5{\pm}4.5$, $15.5{\pm}5.6$ and $11.0{\pm}5.5$, respectively). But, the diameter of CL was significantly correlate(R2 = 0.757) with progesterone levels on day of superovulatory induction. After 7 days of artificial insemination, the embryos at 7 days were collected by uterine flushing after dominant follicle aspiration and superovulation treatment, and evaluated their quality by morphological criteria. Fifty five embryos with excellent, good and fair grade were transferred into 24 recipient cows. Seventeen offsprings, 1 of triplet, 4 of twins and 6 of singlet, were yield from 10 recipient cow. In conclusion, the present study showed that 1) dominant follicle can be determined by ultrasonography with rectal palpation by morphological evaluations, 2) superovulation response after follicular aspiration was not differ at day 9, 11 and 13 of estrus, 3) dominant follicle did not affect to progesterone concentration and diameter of CL, and 4) diameter of CL was significantly correlate to the level of progesterone concentrations in HanWoo.

금속환원법에 의한 바나듐 분말 추출

이동원,허상현,염종택,왕제필,Lee, Dong-Won,Heo, Sang-Hyun,Yeom, Jong-Taek,Wang, Jei-Pil 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.1

The extraction of metallic pure vanadium powder from raw oxide has been tried by Mg-reduction. In first stage, $V_2O_5$ powders as initial raw material was reduced by hydrogen gas into $V_2O_3$ phase. $V_2O_3$ powder was reduced in next stage by magnesium gas at 1,073K for 24 hours. After reduction reaction, the MgO component mixed with reduced vanadium powder were dissolved and removed fully in 10% HCl solution for 5 hours at room temperature. The oxygen content and particle size of finally produced vanadium powders were 0.84 wt% and 1 ${\mu}m$, respectively

탄탈륨 산화물의 마그네슘 가스환원에 의한 탄탈륨 금속분말 제조

이동원,Lee, Dong-Won 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.5

Metallic tantalum powder is manufactured by reducing tantalum oxide ($Ta_2O_5$) with magnesium gas at 1,073-1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50-300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.