B 첨가 고탄소강의 흑연화에 미치는 냉간압연의 영향

박영구,우기도,이창희,류재화,나종필 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The graphitization is affected by the addition of small amount of the elements(such as Si, Al, Ni, B, Cr and Mn etc.) and the pre-treatment(such as cold rolling). Boron is well known element to accelerate the graphitization of cementite in high carbon steels. Also, cold rolling is known to accelerate the graphitization. But the graphitization nucleation mechanism by cold rolling is few reported. Therefore the effect of cold rolling in Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel on the graphitization is investigated quantitatively using hardness test, optical microscope and scanning electron microscope, neutron induced microscopic radiography. The nucleation of graphite in cold-rolled Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel is formed at void which is formed at pearlite/pearlite boundary by cold rolling. But the effect of cold rolling on graphitization in boron addition steel is more effective than that of no boron addition steel due to segregation of BN at void in boron addition steel.

안전 검증을 위한 회전 불변 지문인식 시스템

이승현,류대현,박민순,류충상 한국산업안전학회 1999 한국안전학회지 Vol.14 No.2

본 논문에서는 안전검증 분야로의 응용을 위하여 circular harmonic filter(CHF)와 binary phase extraction joint transform correlator(BPEJTC)에 근거한 회전불변 지문인식 시스템을 제안하였다. 본시스템은 이동 및 회전 변화에 강건하며 실시간으로 지문을 인식할 수 있는 특징을 지닌다. 실시간 구현을 위하여 회전불변 특성을 얻기 위한 복소 CHF는 실수로 구성된다. 시뮬레이션을 통해 본 시스템이 회전된 지문에 대해 강건한 특성이 있음을 보였다. We propose a rotation invariant fingerprint identification system based on the circular harmonic filter (CHF), and binary phase extraction joint transform correlator (BPEJTC) for validation and security verification. It is shown that this system has the shift and rotation robust properties and can recognize the fingerprint in real-time. The complex circular harmonic filter, which is used to obtain the rotation invariance, is converted into the real-valued filter for real-time implementation. Experimental results show that this system has a good performance in the rotated fingerprints.

원자력용 HT9 강과 HT9M 강의 미세조직과 기계적 특성 변화

김성호,박순동,류우석,국일현,송병준 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.12

Microstructure and mechanical properties of HT9 and HT9M steels for liquid metal reactor(LMR) core materials have been investigated. The tempering temperature at which cell structure was formed by rearrangement of dislocations was same in two steels. More carbides were precipitated in HT9 steel due to high carbon content and precipitation of carbides was delayed in HT9M steel. Thus the decrease of hardness with tempering temperature in HT9M steel was lower than that of HT9 steel. The yield strength was decreased, the fine prior austenite grain was formed, and the formation of δ-ferrite was restricted in HT9M steel by decreasing the Cr and carbon content and increasing the Nb content. Thus the impact property of HT9M steel was improved.

활동성 크론병에서 초기 스테로이드 치료 반응에 따른 임상적, 생화학적, 병리학적 인자들에 관한 연구

김영호,장재권,김지은,최규완,박동일,도재혁,백승운,고광철,이풍렬,이종철,현재근,안병훈,김재준,류민규 대한소화기내시경학회 2001 Clinical Endoscopy Vol.22 No.6

Background/Aims: The predictory factors of the response to initial steroid therapy in active Crohn's disease has been controversial in numerous literature reviews. We evaluated any predictory faetor of the response to initial steroid therapy in active Crohn`s disease patients, Methods: The medical records of 32 patients with active Crohn`s disease who clinically responded to oral steroid therapy were retrospectively reviewed. The steroid responsive group was defined as the one showing maintenance of response for more than one month from steroid withdrawal and the steroid dependent group as the one showing relapse or exacerbation during steroid tapering or within 30 days from steroid withdrawal. The clinical, biochemical, and pathologic factors were evaluated. Results: There were 22 male and 10 female patients. The mean age was 28.9 years. The number of steroid responsive and dependent group was 22 (68.8%) and 10 (31.2%), respectively. There were no significant differences between these two groups in age, sex, time to diagnosis, perianal lesion, extent of disease, extraintestinal manifestations, presence of granuloma, presenting features, hemoglobin, ESR, and CRP, except serum albumin level. Conclusions: Serum albumin level was significantly lower in steroid dependent group than steroid responsive group, reflecting severe inflammation in steroid dependent group.

성인에서 반복적인 위장관출혈로 발현한 공장 거대 중복성 낭종

김영호,이경수,이상수,문원,강태욱,최규완,박동일,도재혁,백승운,이풍렬,이종철,김재준,류민규 대한내과학회 2001 대한내과학회지 Vol.61 No.3

Duplication of the alimentary tract is an unusual congenital anomaly which may occur at any level, from the oral cavity to the rectum. Jejunal duplication cyst is quite rare and most of them are presented in infancy with the symptoms of abdominal mass, obstruction, hemorrhage and perforation. But some cases has not been diagnosed till adult if duplication cyst was too small enough to cause symptoms. We report a case of a 28-year-old woman who presented with recurrent gastrointestinal hemorrhage as a result of an ulceration without ectopic mucosa in jejunal duplication cyst and was successfully treated with surgery.(Korean J Med 61:264-269, 2001)

ML 기법에 기반을 둔 측정치 융합기법을 가진 다중표적 방위각 추적 알고리즘

류창수(Chang-Soo Ryu),박주태(Ju-Tae Park),최성운(Sung-Un Choi) 한국산업융합학회 2003 한국산업융합학회 논문집 Vol.6 No.3

Recently, Ryu et al. proposed a multiple target DOA tracking algorithm, which has good features that it has no data association problem and simple structure. But its performance is seriously degraded in the low signal-to-noise ratio. In this paper, a measurement fusion method is presented based on ML(Maximum Likelihood), and the new DOA tracking algorithm is proposed by incorporating the presented fusion method into Ryu's algorithm. The proposed algorithm has a better tracking performance than that of Ryu's algorithm, and it sustains the good features of Ryu's algorithm.

바이모달 트램의 위치 인식 방법 및 정밀 정차 구현

서기원(Seo Ki-Won),박주연(Park Ju-Yeon),이상남(Lee Sang-Nam),류희문(Ryu Hee-Moon),변윤섭(Byun Yeun-Sub) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

This paper presents a method for precisely localizing and parking of bimodal trams. In order to gain an automatically driving system for bimodal trams, precise up-to-date localization, velocity recognition, distance to next station and precise parking location estimation functions are required. This paper proposes a system consisting of control device, steering device, sensor input equipment, driving system, tachometer, vehicle-side sensors, magnetic markers and magnetic sensors. The tram recognizes the precise location via magnetic markers containing information. Parking position and precise distance calculation is embodied by a tachometer. The vehicle-side sensors are used to assure safe station approaching and parking magnetic markers provide improvement of precision while tram parking. This paper provides a system realizing localization and precise parking and afterwards the automatic drive test results are reported and analyzed.

지리산 국립공원 해발 865 m 지점에서 대기에어로졸입자의 입경별 질량농도 특성

류혜지 ( Hye-ji Ryu ),박정호 ( Jeong-ho Park ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.1

Aerosol mass size distributions were investigated at 865 m high the of Jirisan national park. A nanosampler cascade impactor was used to collect aerosols. The atmospheric aerosol particles had a unimodal mass size distribution, which peaked at 0.5-1.0 μm, and a mass aerodynamic diameter of 1.13 μm. The ann ual average concentrations of TSP, PM₁₀, PM_2.5, PM1, PM_0.5 and PM_0.1 were 20.9 μg/㎥, 19.3 μg/㎥, 14.9 μg/㎥, 10.7 μg/㎥, 5.3 μg/㎥, 1.2 μg/㎥, respectively. TSP concentrations were below 30 μg/㎥ during the sampling period. On average PM₁₀, PM_2.5, PM₁, PM_0.5 and PM_0.1 made up 0.91, 0.70, 0.41, 0.19 and 0.07 of TSP, respectively. The annual average of PM_2.5/PM₁₀ ratio was 0.77.

Characteristics of a plasma information variable in phenomenology-based, statistically-tuned virtual metrology to predict silicon dioxide etching depth

Jang, Yunchang,Roh, Hyun-Joon,Park, Seolhye,Jeong, Sangmin,Ryu, Sanywon,Kwon, Ji-Won,Kim, Nam-Kyun,Kim, Gon-Ho Elsevier 2019 Current Applied Physics Vol.19 No.10

<P><B>Abstract</B></P> <P>A phenomenology-based virtual metrology (VM) for monitoring SiO<SUB>2</SUB> etching depth was proposed by Park (2015). It achieved high prediction accuracy by introducing newly developed plasma information (PI) variables as designated inputs, called PI-VM. The PI variables represent the state of the plasma, the sheath, and the target during the process. We investigate how a PI variable can help to improve prediction accuracy of VM and how it plays a special role in the statistical selection. We choose only PI<SUB>EEDF</SUB> among the three PI variables to focus on the investigation. The PI<SUB>EEDF</SUB> is determined from the ratio of line-intensities of optical emission spectroscopy. We apply Pearson's correlation filter (PCF), principal component analysis (PCA), and stepwise variable selection (SVS) as statistical selection methods on the variables set including PI<SUB>EEDF</SUB> or not. Multilinear regression is used to model the VM. This study reveals that PI<SUB>EEDF</SUB> variable is a good variable in terms of independence from other input variables and explanatory power for an output variable. Especially, VM using SVS method applied to variable sets including PI<SUB>EEDF</SUB> achieves the highest accuracy, comparable to Park's PI-VM. This study shows that PI<SUB>EEDF</SUB> variable is particularly useful for monitoring of the fine variations in semiconductor manufacturing process and it also extends the utilization of OES sensor data.</P>

LT, Others : PE-133 ; A case of hepatic hemangioma appearing atypical finding confirmed by dynamic MRI in patients with high risk of hepatocellular carcinoma

( Dong Won Park1 ),( Soo Hyung Ryu1 ),( Myung Ki Oh ),( Seong Yeon Jeong ),( Kyeong Sam Ok ),( Jae Chan Shim ),( Jin Nam Kim ),( You Sun Kim ),( Jeong Seop Moon ) 대한간학회 2012 춘·추계 학술대회 (KASL) Vol.2012 No.-

Background: Hemangioma is the most common benign hepatic tumor. Many hepatic hemangiomas tend to be found incidentally, but should be differentiated from malignant tumors. We report an interesting case of hepatic hemangioma in patient who has high risks of hepatocellular carcinoma. Case: A 52-year-old woman, who was a chronic alcoholic abuser and hepatitis C virus carrier with no treatment experience, was admitted due to diarrhea. The patient had suffered from intermittent abdominal pain in the right subcostal area for recent 3 months. Also the patient had easy bruising and frequent epistaxis. She had used oral contraceptives for almost 20 years. Systolic blood pressure was 160 mmHg and diastolic blood pressure was 80 mmHg. Body temperature was normal. Physical examination revealed icteric sclerae and tenderness in right upper quadrant of the abdomen. Laboratory study showed platelet count of 31,000/ul, AST/ALT of 302/127 IU/L, and total bilirubin of 2.7 mg/dl. 3-phased contrast-enhanced abdominal computed tomography (CT) revealed a 4 cm × 4 cm sized hepatic mass involving both segment 5 and 6. Abdominal CT finding suggested hepatic hemangioma, however, typical finding of hemagioma was unclear, therefore, could not rule out the malignancy. Since she had risk factors for hepatocellular carcinoma, abdominal ultrasonography was performed for further evaluation. But abdominal ultrasonography also showed atypical finding. The confirmative diagnosis could be done by dynamic magnetic resonance imaging (MRI) using primovist®, which is an innovative liver cell-specific contrast medium. Dynamic MRI presented peripheral globular enhancement and a centripetal fill-in pattern, confirmatory findings of hepatic hemangioma, on the delayed image. The patient got relief from abdominal pain and diarrhea during admission, now is being followed-up at a general out-patient clinics. Conclusions: Hemangiomas with atypical abdominal CT and ultrasonographic findings in patients with high risks of hepatocellular carcinoma can be easily characterized with primovist-enhanced dynamic MRI.