자유드로잉 제품과 패드를 설치한 드로잉 제품의 특성

고관영,명노훈,하종성,이창수,최창권,최병용,허기영,김광수,김동수,장종훈,장윤철,김세환,오정민,하민정,박향자 울산과학대학 2000 연구논문집 Vol.27 No.1

본 연구는 자체 제작한 전체 패드가 부착된 드로잉 금형을 이용하여 SUS, 연강, AI, 6:4황동 판재를 드로잉 가공하여 생산된 제품의 특성을 자유드로잉 하여 얻은 제품의 특성과 비교 분석하였다. SUS 판재의 경우 제품에 발생하는 현상은 벽 주름, 구변주름, 수직 파단, 드로잉상처, 이어링이 발생하였으며 길이변화는 펀치어깨부분에서 가장 많이 늘어남을 볼 수 있었고 벽 주름 부분에 있어서 접혀진 부분은 상대적으로 적게 늘어남을 볼 수 있었다. 연강 판재는 SUS 판재에서 보여준 현상을 나타내었으나 SUS 판재에 비해 수직 파단은 적게 일어난 반면 이어링이 더 크게 일어났다. AI 판재의 경우 수직 파단은 일어나지 않았으나 플랜지 주름과 밑면터짐이 발생하였다. 6:4황동의 경우는 전체패드의 AI 판재 드로잉에서와 같이 밑면터짐과 플랜지 주름의 발생이 일어났다.

Extended Hall–Petch Relationships for Yield, Cleavage and Intergranular Fracture Strengths of bcc Steel and Its Deformation and Fracture Behaviors

N. H. Heo,Y.‑U. Heo,S. K. Kwon,N. J. Kim,S.‑J. Kim,H.‑C. Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

Extended Hall–Petch relationships for yield (y ), cleavage (cl ) and intergranular fracture (ig) strengths of pure iron havebeen established through the direct calculation of the proportional constant (k) and the estimation of the friction stress (0) . The magnitude orders of k and0 are generally ky< kcl< kig and y0< cl0< ig0 , respectively. Based on the Hall–Petchrelationships, micro-yielding in a bcc steel occurs at the instance that the pile-up dislocations within a specific grain showingthe Schmid factor of 0.5 propagate into the neighboring grain. The initial brittle crack is formed at the instance that the flowstrength exceeds the brittle fracture strength. Once the brittle crack is formed, it grows catastrophically. Due to the smallestand ky andy0 , the cleavage and the intergranular fracture occur always after micro-yielding. The {100} cleavage fracture ofthe steel is due to the lowest theoretical {100} cleavage strength. Due to the thermal components included in cleavage andintergranular fracture strengths, they show also the temperature and strain rate dependence observed in yield strength. Theincrease in susceptibility to brittle fracture with decreasing temperature and increasing strain rate is due to the increase indislocation density which causes the high work hardening rate.

Forming and Drawing Characteristics of Tailor Welded Sheets in a Circular Drawbead

Heo Y.M,Kim H.J,Seo D.G,Kim N.S 기계기술연구소 2000 성균관대학교 논문집 기계기술편 Vol.2 No.1

Circular drawbead forming and drawing characteristics of CO2 laser welded SPC1 blanks are investigated by experiments and numerical analysis. During the drawbead forming process, the distributions of major strains on upper and lower skins of the specimens are measured. During the drawing process, the drawing forces and the strain distributions are investigated. For numerical analysis, DYNA-3D and SGTAS, a developed rigid-plastic finite-element computer program are used. Numerical results predicted the deformation characteristics well in comparison with experiments. It is concluded that the strains and restraining forces during the forming and the drawing processes show different patterns according to the combination of welded blanks.

악성 조직구증의 진단 및 치료 경험

이종태(J . T . Lee),이근석(K . S . Lee),김인호(I . H . Kim),방영주(Y . J . Bang),박선양(S . Y . Park),김병국(B . K . Kim),김노경(N . N . Kim),허대석(D . S . Heo) 대한내과학회 1996 대한내과학회지 Vol.51 No.4

N/A Objectives: Malignant histiocytosis is a rare, rapidly fatal disorder, characterized by systemic proliferation of abnormal histiocytes. Most patients present with fever, organomegaly, and pancytopenia, and die within a few months. Although malignant histiocytosis represents diagnostically an important histiocytic disorder, its pathogenesis, natural history, response to therapy are not well known. In Korea, there are few reports on malignant histiocytosis. The purpose of this investigation is to assess the clinical spectrum natural history, laboratory findings, histopathologic findings response to therapy of malignant histijiocytos is diagnosed at Seoul national university hospital. Methods: The clinical records and histologic materials from 29 cases of malignant histiocytosis diagnosed at Seoul national university hospital between 1985 and 1994 have been reviewed. The criteria for the histopathologic diagnosis of malignant histiocytosis were the presence of large, abnormal malignant histiocytes with frequent mistosis to be distinguished from reactive histiocytic proliferation. All histologic materials were fixed in formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Bone marrow aspirates were stained with Jener-Giemsa. of 29 patients, 20 patients were treated with combination chemotherapy; CHOP in 8 patients, COPBLAM in 3 patients, BVP in 7 patients, C-MOPP in 1 patient, Pdplusvincristine in 1 patient. Results: The median age was 32 years, with a 2.2:1 male to female prepondance. Major physical findings included temperature elevation (93%), hepatomegaly (90%), splenomegaly (86%), jaundice (5%). Common laboratory findings were anemia (86%), thrombocytopenia (90%), splenomegaly (86%), jaundice (45%). Common laboratory findings were anemia (86%), thrombocytopenia (90%), leukopenia (72%), hypocalcemia (97%), abnormal liver function test (100%). Histologic features observed in bone marrow were increased histiocytes, atypical immature histiocytic infiltration with hemophagocytosis. Histologic features observed in lymph node were destruction of normal structure with infiltration and proliferation of immature histiocytes. Prominent features observed in liver were sinusoidal histiocytic infiltration. The response to treatment was encouraging. One patient achieved a completed remission (5%), 5 patients achieved a partial remission (25%), and overall response rates were 30%. Conclusion: The distinctive clinical and histologic findings warrant recognition and separation of malignant histiocytosis from other histiocytic and hematopoietic disorders and long-term survival is possible in some patients if treated early and aggressively with combination chemotherapy.

Genetic basis of antimicrobial resistance and clonal dynamics of carbapenem-resistant Acinetobacter baumannii sequence type 191 in a Korean hospital

Selasi, G.N.,Nicholas, A.,Jeon, H.,Lee, Y.C.,Yoo, J.R.,Heo, S.T.,Lee, J.C. Elsevier Science 2015 INFECTION GENETICS AND EVOLUTION Vol.36 No.-

This study investigated the genetic basis of antimicrobial resistance and the epidemiological characteristics of 125 carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected from 2011 to 2012 in a Korean hospital. All CRAB isolates showed an extensively drug-resistant phenotype, but were susceptible to tigecycline. The bla<SUB>OXA-23</SUB> and armA genes were mainly responsible for resistance to carbapenems and aminoglycosides, respectively. Four colistin-resistant CRAB isolates with different pulsotypes were identified. All four colistin-resistant isolates had a deletion at nucleotide 776 in lpxA, while one also had an insertion at nucleotide 732 in lpxA. All CRAB isolates belonged to three sequence types (STs): ST191 (n=118), ST208 (n=6), and ST436 (n=1), but were classified into 33 arbitrary pulsotypes. Of the CRAB ST191 isolates, two main arbitrary pulsotypes 5 (n=20) and 18 (n=17) emerged sequentially, but were not clonally related to CRAB isolates collected from 2009 to 2010 in the same hospital. Furthermore, of the two main pulsotypes identified among CRAB ST191 isolates from 2009 to 2010, one was clonally related to sporadic CRAB ST191 isolates from 2011 to 2012, but the other was not related to any CRAB isolate from 2011 to 2012. In conclusion, this study shows the clonal dynamics of CRAB ST191 isolates in a Korean hospital during the last four years.

Optimized surface passivation of n and p type silicon wafers using hydrogenated SiN_x layers

Dao, V.A.,Heo, J.,Kim, Y.,Kim, K.,Lakshminarayan, N.,Yi, J. North-Holland 2010 Journal of non-crystalline solids Vol.356 No.50

We have investigated surface passivation of n and p type silicon wafers, obtained by controlling silicon-hydrogen bonding and fixed charge densities with the use of hydrogenated SiN<SUB>x</SUB> films. The hydrogenated SiN<SUB>x</SUB> films were deposited by single PECVD at 13.56MHz with SiH<SUB>4</SUB>/NH<SUB>3</SUB> gas mixture. The hydrogenated SiN<SUB>x</SUB> films of refractive indices 2.55-1.92 and high optical band-gap (>3.1eV) were obtained by varying the hydrogenated SiN<SUB>x</SUB> film composition. The fixed charge densities, hydrogen-bonding and carrier lifetime performance in n and p type silicon wafer were analyzed. The highest fixed positive charge of 2.66x10<SUP>12</SUP> (cm<SUP>-2</SUP>) was for the hydrogenated SiN<SUB>x</SUB> film composition of 1.21. Fourier transform infrared spectroscopy measurement was carried out to evaluate the bonding concentration of Si-H and N-H. The minority carrier lifetimes of the hydrogenated SiN<SUB>x</SUB> passivated silicon wafers were up to 153μs and 84μs for p and n type, respectively. Mechanism of surface passivation depends on the type of silicon wafer. The higher Si-H bond density is the key point of n type passivation quality. The large fixed positive charge is used to measure p type passivation quality.

시설원예 전용 농약의 개발현황과 사용법

허노열 韓國施設園藝硏究會 1996 施設園藝硏究 Vol.9 No.1

미세 치수 조절 가능한 스텝 커터의 개발

허윤녕,황종대,정윤교 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

As demands for being economical, precise drilling process is on the increase. Therefore, the objective of this study is to develop a step cutter that can be controllable through micro dimension and can be changed from seperate manufacturing process into an integrated one. The step cutter is designed with a 3D geometric Modeling and the design could be modified easily by using parametric modeling method. The step cutter is assembled by parts made up of 5-axis machining and sintering. The objective of the manufactured step cutter is reliability and commerciality through a performance evaluation experiment.

施設菜蔬 主要病害 發生生態와 省力 防除技術

許魯烈 韓國施設園藝硏究會 1993 施設園藝硏究 Vol.6 No.1

C++ 프로그램을 위한 복잡도 척도

유철중,오재철,허영남 순천대학교 기초과학연구소 1990 基礎科學硏究誌 Vol.1 No.-

객체중심언어에 있어서 자료추상화(data abstraction)에 의한 켑슐화(encapsulation)와 상속성(inheritance)이 가장 중요한 개념으로 인식되고 있다. 특히, 프로그램이 객체(object)간의 메시지 전달(message passing)에 의해서 수행되고 상속에 의해 재사용되는 특성이 있으므로, 이러한 객체중심프로그램의 복잡도(complexity)를 보다 잘 나타내기 위해서는 클래스(class)에 기반을 둔 척도가 요구된다. 따라서 본 논문에서는 객체중심 언어인 C++에 적합한 척도를 얻기 위해 고려하여야 할 특성들을 제시하였으며 이를 바탕으로 클래스에 기반을 둔 새로운 복잡도 척도를 제안하고 그 타당성을 보였다. Object oriented languages have major properties of encapsulation and inheritance by data abstraction. In this paper, we discuss major properties of several complexity metrics, and also object oriented programs. We propose metrics complexity measurement of object oriented programs (especially, C++), and evaluate the validity of the proposed measures. The metric is a class-based measures.