에너지 회생 기법을 사용한 초고속 전동 사출성형기 개발

유현재,유성철,현창훈,박경호,Yu, Hyeon-Jae,Yoo, Sung-Chul,Hyun, Chang-Hoon,Park, Kyoung-Ho 한국금형공학회 2016 한국금형공학회지 Vol.10 No.2

High-speed and high-torque performance is required in the ultra-high speed electric injection molding machine field. To implement this performance, the big-size inverter is needed and the corresponding converter should be used. In this case, the whole cost for configuring the system will be increased. In this paper, we introduce a method which is able to reduce the energy and the cost for configuring the system using the energy regeneration. The energy regeneration method is based on reusing the regeneration power generated at the electric motor during decelerating the injection motion. In this paper, we demonstrate the effectiveness of the method by using the ultra-high speed injection motion.

감시정찰 센서네트워크 상에서 자기센서를 이용한 소총인원 탐지

유현재(Hyun-Jae Yoo),정준(Jun Jung),조정배(Jeong-Bae Cho),권철희(Cheol-Hee Kwon),이상명(Sang-Myung Lee) 한국정보과학회 2013 한국정보과학회 학술발표논문집 Vol.2013 No.11

태양광 발전량과 기상변수간 상관관계 분석

유현재(Hyun-jae Yoo),공승준(Seung-jun Gong),김종민(Jong-min Kim) 한국정보통신학회 2022 한국정보통신학회 종합학술대회 논문집 Vol.26 No.1

국내 단층지진원의 지진활동성 분석

유현재(Hyun Jae Yoo),강태섭(Tae-Seob Kang) 대한지질학회 2019 대한지질학회 학술대회 Vol.2019 No.10

조선후기 금위영의 재정운영과 그 성격

유현재(Yoo Hyun-jae) 한국역사연구회 2016 역사와 현실 Vol.- No.102

The Geum’wi-yeong was one of the central military offices that operated in the latter half of the Joseon dynasty and was in charge of defending the capital and the palace (especially the king). In order to fulfill its purpose and properly do its job, the office had to spend much money. But coming into the 19thcentury,theGeum’wi-yeong office, which was originally a military body, no longer shifted soldiers and instead involved itself in financial affairs and projects, primarily assisting other financial bodies inside the government. Its new role can be confirmed from Takji jeonbu-go, documents of the Finance “Hojo” Ministry, which show that the military budget under jurisdiction of the Geum’wi-yeong office was being diverted to the Finance ministry. According to these records, the Geum’wi-yeong supplemented the budget of the Hojo ministry, which had already gone into deficit, by employing a method that is described as “additional submissions (‘Gaib’).” Of the entire “Gaib” income of the Finance Ministry in the early 19thcentury, 10percent came from the Geum’wi-yeong office, showing that the Geum’wi-yeong office played a substantial role in supporting the Hojo ministry in financial terms. In other words, the Geum’wi-yeong office, a military body in the late Joseon era, evolved into a financial support mechanism for the Hojo ministry in the 19thcentury and, in the process, helped sustain dynastic stability.

보이차 생차(生茶)로부터 항산화 Flavonoids 분리 및 화학구조 규명

유현재(Hyun Jae Yoo),정하숙(Ha Sook Chung) 한국차학회 2020 한국차학회지 Vol.26 No.2

차나무(Camellia sinensis L.)의 잎으로 제조된 차는 가공방법에 따라 불발효차, 반발효차, 발효차 및 후발효차로 구분된다. 보이차(Pu-erh tea)는 중국 관동성과 운남성 일대의 대엽종 차나무 잎을 건조시켜 제조되는 대표적인 후발효차이며, 따뜻하고 습한 환경에 차잎을 장시간 노출시켜 Aspergillus 속과 Penicillium 속 등의 미생물이 분비하는 효소에 의해 발효가 진행되며 특유의 색, 향과 맛을 나타내고 있다. 본 연구는 보이차 생차의 주요식물 화학성분을 규명할 목적으로 시행되었다. 보이차 생차를 70% ethyl alcohol로 추출하여 항산화능이 우수한ethyl acetate 가용성 분획(IC50: 28.7 µg/mL)으로부터 silica gel과 Sephadex LH-20 open column chromatography를시행하여 보이차 생차의 주요 flavonoids 3종 화합물을 단리하고, 기기분석을 통해 kaempferol (1), kaempferol3-O-β-D-galactopyranoside (2) 및 quercetin (3)으로 그들의 화학구조를 규명하였다. 분리된 화합물의 DPPH radical-scavenging activities (IC50, µM/mL)는 각각 18.20, 33.91, 10.76으로 확인되었으며, 화합물 3의 경우 항산화제로 널리 활용되는 gallic acid (IC50: 12.02 μM)보다 높은 항산화능을 나타내었다. 이는 aromatic B-ring에 결합하고 있는 ortho hydroxyl groups에 의한 것으로 판단된다. Based on their degree of fermentation, teas (Camellia sinensis L.) are classified as non-fermented, partially fermented, fully fermented and post-fermented. Pu-erh tea is characterized by the post-fermented processing, which utilizes microorganisms such as Aspergillus niger to improve the color, taste, flavor, and biological activities. This study investigates the phytochemicals and biological activities of raw Pu-erh tea. Three flavonoids were isolated by subjecting 70% ethyl alcohol extracts of raw Pu-erh tea to activity-guided fractionation and isolation methods, and their chemical structure and biological activities were subsequently identified. The chemical structures were identified as kaempferol (1), kaempferol 3-O-β-D-galactopyranoside (2), and quercetin (3), by applying spectroscopic analyses including UV-Vis, ESI-MS, 1 H-NMR, 13C-NMR, 1 H-1 H COSY, and 1 H-13C HMQC spectral analyses with coloring reaction. The DPPH radical-scavenging assay revealed potent anti-oxidant capacities of compounds 1-3, with IC50 values of 18.20, 33.91, and 10.76 µM, respectively.

논문 : 16세기 추포 유통과 그 성격

유현재 ( Hyun Jae Yoo ) 서울대학교 국사학과 2006 韓國史論 Vol.52 No.-

18세기 은전비가(銀錢比價)의 변동과 의미

유현재(Yoo, Hyun-jae) 한국역사연구회 2015 역사와 현실 Vol.- No.97

Examined in this article is the fact that Sangpyeong Tongbo, the Joseon coin, was devised and circulated by the Joseon government in the dynasty’s second half, as the government needed those coins for some fiscal reasons. Compared to Chinese and Japanese cases, in which coins were created and circulated in an environment quite similar to the Joseon case, the Joseon government’s coin policy seems to have displayed characteristics of its own. Particularly noticed is the fact that the value of a coin, represented in silver, varied in all three countries. Joseon and China imported raw materials, needed for coin production, from Japan. Circumstances surrounding coin production in both countries seem to have been quite similar. All coins, regardless of the country that produced them, harbored the same value which was recognized with the same amount of silver, as long as they were created with raw material (imported from Japan) which had the same price and were produced under similar circumstances. But in the Joseon case, initially there were some differences, from their Chinese and Japanese counterparts. The Joseon government modified the price of the coin as they saw fit, in order to secure a needed amount of profit margin (seigniorage) and sometimes even maximize it. This was a risky choice on the government’s part considering the delicate nature of currency circulation. The Joseon government decided to do so nonetheless, but this artificial devaluation policy failed to produce an outcome that would last as much as the government had hoped for.

연구논문 : 임란(壬亂) 이후 주전론(鑄錢論)과 왜전(倭錢)의 수입

유현재 ( Hyun Jae Yoo ) 동국사학회 2014 동국사학 Vol.56 No.-

본 논문은 양란 이후 나타난 동전 제작 논의 과정과 수입한 왜전의 역할에 대해 살펴보고 있다. 그 동안 화폐연구에서는 동전의 주된 성격을 상품화폐경제에 상응하여 나타난 매체로 이해하는 경향이 강했다. 따라서 임진왜란과 병자호란이라는 국가적인 위기 상황에서 동전을 제작하거나 유통시키는 기록은 큰 의미를 두지 않았다. 전란 때문에 상품화폐경제가 발달할 수 있는 경제적 조건이 구비되지 않았다는 전제 때문이었다. 특히 병자호란 이후 왜로부터 동전을 수입한다고 하는 기록을 사실로 받아들일 경우 당시 조선의 경제수준이 일본보다 뒤떨어진다는 의미로 해석될 수 있었기 때문에 그동안 연구에서는 사실로 인정하지 않았다. 그러나 전근대 화폐는 재정수단으로 큰 역할을 담당하고 있었다. 따라서 조선에서는 임진왜란 당시에도 동전제작을 논의 하였고 병자호란 이후에는 긴급한 재정적 필요에 따라 왜전을 완제품으로 구입하였다. 당시 수입한 왜전의 규모는 정확하게 제시되어 있지 않지만 최소값으로 계산할 때에 쌀 5천 석 규모였다. 그 규모는 크지 않았지만 조선은 왜전 수입을 통해 긴급한 재정적 문제를 해결하려고 했다. 쌀이나 현물은 생산에 한계가 있었고 전란 이후라 이동과 생산에 큰 제약이 있었기 때문에 비록 적은 수량이지만 동전을 수입하여 긴급한 재정수요를 충당하려고 했다. 그 규모와 회수에 대해서는 기록 부족으로 정확하게 추정이 불가능하지만 당시 양란 이후 조선은 동전을 적극적인 재정수단으로 활용하고 있다는 사실을 왜전 수입에 대한 기록을 통해 확인할 수 있다. 당시 조선은 재정적인 문제를 해결하기 위해 규모는 크지 않았지만 동전을 활용하고 있었다. The purpose of this dissertation is to examine a debate on the making coin and the role of imported Japanese coin, which are shown after two wars (兩亂). Coin has been understood as a medium appeared corresponding to commodity economy; accordingly, there has been a lack of understanding on the manufacture or the distribution of coin during the crisis situations such as war. Particularly, importing coin from Japan could be interpreted that Choson has lower economic level than Japan; hence, this fact hasn`t even been acknowledged. However, premodern currency actually played an important role as the financial means because Choson could supply urgent demand with currency under the crisis like war. Therefore, Choson government discussed making coin at the time of Japanese Invasion (1592), and purchased complete product from Japan according to urgent financial needs after the Manchu war (1636). We cannot know exact scale of imported coin from Japan because it was not recorded exactly, but if we reckon a minimum value of it, it would be 5,000 sok of rice. Even though the scale was not that large, Choson could resolve the issue of urgent financial problems through this; in other words, importing coin from Japan can be evaluated the debate on the manufacture and distribution of coin and importing coin from Japan as an active policy for overcoming its financial crisis after war.

무인기 지상통제체계 보안 적용 방안 설계

유현재(Hyun-Jae Yoo),고정환(Jung-Whan Ko),권철희(Cheol-Hee Kwon) 한국정보기술학회 2016 Proceedings of KIIT Conference Vol.2016 No.6