Effects of the Ultrasound Treatment on Reaction Rates in the RH Processor Water Model System

Yong‑tae Kim,Kyung‑woo Yi 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

Ruhrstahl–Heraeus (RH) processor is widely applied to the refining process to produce steel with very low carbon contents. In this study, to investigate the effect of ultrasound treatment on RH decarburization process, we have developed two kinds ofthe water models simulated the RH process and study the removal rate of dissolved oxygen. The one is the RH water modelof 1/8 size of actual RH degasser simulated the late-stage of the RH process when surface reaction and plume reaction mainlyoccur. Through this model, it is found that the ultrasound treatment accelerates dissolved oxygen removal reaction and thistendency is maintained even at low concentrations. Also, the results show that there is a difference in the degassing efficiencydepending on the frequencies and the positions of the ultrasonic transducer. Also, to simulate the Early-stage Reaction ofthe process including the inner-site reaction which is difficult to investigate through the RH water model, the other watermodel has been developed (the RH-ER water model). This model shows that the ultrasound treatment facilitates the earlystagereaction including inner-site reaction, like the RH water model. These results show that the addition of the ultrasoundtreatment can accelerate decarburization reaction during RH process compared to conventional process.

Effects of Variation of Heat Flux Released from the Meniscus on the Surface Shape of the Solidified Shell During Continuous Casting

Yong‑tae Kim,Kyung‑woo Yi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

Mold oscillations, widely used in continuous casting for infiltrating the mold flux between the mold and the solidified shell,change periodically the heat flux from the meniscus to mold. These variations of the heat flux affect the solidification behaviornear an initial solidification position. Because the surface shape of the solidified shell is influenced by the initial solidificationbehavior, it is important to understand the relation between the mold oscillation, the heat flux and initial solidificationbehavior. In the present study, we developed a numerical model that simulates the flow and thermal behavior of the moldflux near the meniscus. Using this model, we analyze the effects of the variations of the heat flux from the meniscus on theinitial solidification position and suggest the formation mechanism of the oscillation marks (OMs) and the hooks. Also, wewill present quantitative results about the depth of the OMs and the length of the hooks at the conditions used in the presentstudy. The factors that influence the hooks’ types and the causes of the irregularity of the shell surface are also discussed.

Genome-wide investigation of a Korean synthetic breed, Woori-Heukdon using the Illumina PorcineSNP60K BeadChip

Yong‑Min Kim,Ha‑Seung Seong,Jung‑Jae Lee,Da‑Hye Son,Jin‑Su Kim,Soo‑Jin Sa,Young‑Sin Kim,Tae‑Jeong Choi,Kyu‑Ho Cho,Joon‑Ki Hong,Jung‑Woo Choi,Eun‑Seok Cho 한국유전학회 2020 Genes & Genomics Vol.42 No.12

Background: Woori-Heukdon (KWH) is a Korean synthetic pig breed generated using Chookjin-Duroc (KCD), Chookjin-Chamdon (KCC), and their crossbreds. Currently, there is a severe lack of studies investigating the Korean breed populations including wild boars (KWB) throughout the genome. Objective: This study was performed to investigate the genetic characteristics of Korean pig populations at the genome-wide level. Methods: Using the SNP dataset derived from genotyped and downloaded datasets using the Illumina PorcineSNP60K BeadChip, we compared the genomes of 532 individuals derived from 23 pig breeds to assess the genetic diversity, inbreeding coefficient, genetic differentiation, and population structure. Results: KWB showed the lowest average expected heterozygosity (HE = 0.1904), while KWH showed the highest genetic diversity (HE = 0.02859) among Korean populations. We verified that the genetic composition of KWH, showing USD of 74.8% and KCC of 25.2% in ADMIXTURE analysis. In population structure analyses, KCC was consistently shown to be separated from other pig populations. In addition, we observed gene flow from Western pigs to a part of Chinese populations. Conclusion: This study showed that Korean native pigs, KCC have genetic differences in comparison with Chinese and Western pigs; despite some historical records and recent genetic studies, we could not find any clear evidence that KCC was significantly influenced by Chinese or Western breeds in this study. We also verified the theoretical genomic composition of KWH at the molecular level in structure analyses. To our knowledge, this is the first genomic study to investigate the genomic characteristics of KWH and KCC.

교류여자방식 브러시리스 동기전동기의 공간벡터에 의한 토오크제어

우정인,정영일,노태균,조용길,신동률 東亞大學校 附設 情報通信硏究所 1997 情報通信硏究所論文誌 Vol.5 No.1

In the paper, a vector control method for a AC-excited BLSM(Brushless Synchronous Motor) is proposed. The BLSM has a feature that separate exciter is not needed for excitation. The proposed method is described in two parts as follow, one is the design of drive and the other is a modeling for its imlpementation. Rotor flux is estimated using inditect sensing method based on voltage equation in the synchronously rotation reference frame. And rotor position os calculated from rotor angular velocity and stator current. Through computer simulation results of this prorosed system, it is shown that the BLSM drive has a ability of precision torque control from the static and dynamic performances.

대장암 환자에서의 담즙 암태아성 항원(CEA)

김종우,박용태,정철운,권성원,장항석,손석우,안대호,이경포 대한대장항문학회 2000 Annals of Coloproctolgy Vol.16 No.6

낙동강 하구일대에서 기록된 조류

우용태,이종남,허위행 경희대학교 한국조류연구소 1997 연구보고 Vol.6 No.1

본 연구는 조사자가 낙동강 하구 일대에서 기록한 조류들을 정리한 것으로 총 15目 43科 209種이며, 이 중 수조류(水鳥類 Waterbirds)가 133種(63.6%)이며 명금류(鳴禽類 Oscines) 42種(20.1%), 맹금류(猛禽類 Raptores) 18種(8.6%)이다. 移動類型別로 보면 보면 텃새가 26種(12.4%)이고, 철새(候鳥 Migratory birds)는 171種(81.8%)인데 철새 중에서는 겨울새가 89種(42.6%), 나그네새가 53種(25.4%), 여름새가 29種(13.9%)이며 길잃은새(迷鳥 Vagrant)는 12種(5.7%)이다. 천연기념물로 지정된 종은 황새, 흑고니, 큰고니, 고니, 두루미, 재두루미, 노랑부리저어새, 저어새, 느시, 흑두루미, 흰꼬리수리, 참수리, 검독수리, 독수리, 새매, 잿빛개구리매, 알락개구리매, 개구리매, 매, 황조롱이, 칡부엉이, 쇠부엉이, 흑기러기, 개리, 검은머리물떼새, 원앙이로 26종이었다. IUCN의 적색자료서의 기준 및 범주에 속하는 종(원, 1994)은 황새, 가창오리, 개리, 붉은가슴흰죽기, 참수리, 두루미, 흑두루미, 재두루미, 알락뜸부기, 쇠청다리도요사촌, 검은머리갈매기로 11종이었고 준위협종(Non-threatened)은 큰덤불해오라기, 원앙이, 알락꼬리마도요, 고대갈매기, 쇠검은머리쑥새의 5종이었다. 절종된 종은 원앙사촌이었으며 저자에 의해 낙동강에서 처음으로 기록하고 한국조류목록에 등재한 종은 고대갈매기, 수리갈매기, 붉은발제비갈매기, 붉은배지느러미발도요 4종이다. This study shows the birds recorded in the Nakdong river estuary by the authors. The birds recorded in the Nakdong river estuary were 15 orders, 43 families, 209 species. Waterbirds were 133 species (63.6%), Oscines were 42 species (20.1%) and Raptors were 18 species (8.6%). Among them, resident were 26 species (12.4%) and migratory birds were 171 species (81.8%). Migratory birds include 89 species of winter visitor (42.6%), 53 species of passage migrant (25.4%) and 29 species of summer visitor (13.9%) and 12 Species of Vagrant (5.7%). The species designated as a natural monuments are 26 species: Ciconia ciconia boyciana, Cygnus olor, Cygnus cygnus, Cygnus columbianus jankowskii, Grus japonensis, Grus vipio, Platalea leucorodia leucorodia, Platalea minor, Otis tarda dybowskii, Grus monacha, Haliaeetus albicilla, Haliaeetus pelagicus pelagicus, Aquila chrysaetos japonica, Aegypius monachus, Accipiter nisus nisosimilis, Circus cyaneus cyaneus, Circus melanoleucos, Circus aeruginosus spilonotus, Falco peregrinus japonensis, Falco tinnunculus interstinctus, Asio otus otus, Asio flammeus flammeus, Branta bernicla orientalis, Anser cygnoides, Haematopus ostralegus osculans, Aix galericulata. The species listed in Red Data Book of IUCN were 15 species: Ciconia ciconia boyciana, Anas formosa, Anser cygnoides, Aythya baeri, Haliaeetus pelagicus pelagicus, Grus japonensis, Grus monacha, Grus vipio, Porzana exquisita, Tringa guttifer, Larus saundersi. Non-threatened species were 5 species: Ixobrychus eurythmus, Aix galericulata, Numenius madagascariensis, Larus relictus, Emberiza yessoensis. Extint species was Tadorna cristata. First recorded species in the Nakdong river estuary by authors were 4 species of Larus relictus, Larus glaucescens, Sterna hirundo miussensis, Phalaropus fulicarius.

경북 일원의 포유류상

우용태,이종남,허위행 慶星大學校 1998 論文集 Vol.19 No.2

1. This is a part of the second nation-wide survey of natural environment by the Ministry of Environment of Korea in 1997 and the Mammalia were surveyed in the area of Daegu and Dalsung. 2. The survey area was divided into 6 parts and the survey was carried out by the visiting and inquiry method. 3. The Mammalia surveyed were classified into 6 orders, 12 familiesm and 27 species. 4. A total of 27 species surveyed by this survey was only 35.5% of 76 species of Mammalia (except CETACEA and PINNIPEDIA) inhabited in Korea. 5. Among the 27 species, 17 species were surveyed at all the 6 parts, 3 species were natural monuments, and 7 species were rare and endangered species. 6. The result showed that several species decreased because of the destroy of habitat by the deforestation and illegal capture.

반송용 편측식 선형기기의 추력제어에 의한 특성해석

우정인,신동률,조용길,노태균 東亞大學校 大學院 1999 大學院論文集 Vol.24 No.-

본 논문에서는 PWM 인버터 구동 편측식 선형유도 전동기(이하 SLIM)의 공간백터 제어와 PI 제어를 통한 추력 제어를 행한다. 1차측 권선과 SLIM의 2차측 구조 사이에서 발생하는 공극길이의 떨림은 빠른 응답특성을 얻기위해서 최소화 되어야 한다. 먼저, SLIM의 전압방정식이 추력과 수직력 특성을 해석하기 위하여 d-q축 등가회로로서 나타내어진다. 또한, d-q축 등가회로의 모델링과 해석은 등가회로상에서 전류변동에 따른 강인한 과도 추력특성을 얻을 수 있다. 지령속도와 추력에 의한 SLIM의 직접구동 결과는 실험을 통해서 확인된다.

정현추종 제어기를 이용한 전압형 PWM 컨버터의 입력전류제어

우정인,정기화,최선영,허태원 東亞大學校 附設 情報通信硏究所 1999 情報通信硏究所論文誌 Vol.7 No.1

This paper presents the sinusoidal tracking controllr in order to eliminate the steady state control error and to improve the transient characteristics for input current in voltage source PWN congerter. A general mathematical model with switching functions of the PWM converter that is represented as differential equation is established. The proposed model in current control system that does not require coordinate transformations is described. It is proved that the steady state deviation reduces to zero from a transfer function of input current control system. The sinusoidal tracking controller is realized by differential equations for the LC equivalent circuit. From simulations and experimental work, it is verified that the control system can eliminate the steady state error of input current and also improve the transient state characteristic.

경북 일원의 양서 . 파충류상

우용태,이종남,허위행 慶星大學校 1998 論文集 Vol.19 No.2

1. This is a part of the second nation-side survey of natural environment by the Ministry of Environment of Korea in 1997 and the Amphibians and Reptiles were surveyed in the area of Daegu and Dalsung. 2. The survey area was divided into 6 parts and the survey was carried out by the visiting and inquiry method. 3. The Amphibians surveyed were calssified into 2 orders, 6 families and 9 species, and Reptiles were classified into 2 orders, 6 families and 14 species, respectively. 4. Among the 23 species, 16 species, were surveyed at all the 6 parts. And among the surveyed species, 10 were rare or endangered species. 5. The result showed that several species decreased because of the destroy of habitat by the deforestation, overcatching for the materials of Korean medicine, and especially the prey by introduced foreign species-Rana catesbiana. 6. Elaphe schrenckii distributed in some areas and Gekko japonicus, having been reported extinct after 1920, distributed in Mt. Pi-suhl, Chung-ryong, and Choi-jung.