선박용 고강도 Al합금(5456-H116)의 최적 방식 전위결정에 관한 연구

김성종,고재용,Kim Sung-Jong,Ko Jae-Yong 한국마린엔지니어링학회 2006 한국마린엔지니어링학회지 Vol.30 No.1

Recently, interest in using Al alloys in ship construction instead of fiber-reinforced plastic (FRP) has increased because of the advantages of A) alloy ships over FRP ships, including high speed, increased load capacity. and ease of recycling. This paper investigated the mechanical and electrochemical properties of Al alloys in a slow strain rate test under various potential conditions. These results will provide reference data for ship design by determining the optimum protection potential regarding hydrogen embrittlement and stress corrosion cracking. In general, Al and Al alloys do not corrode on formation of a film that has resistance to corrosion in neutral solutions. In seawater, however, $Cl^-$ ions lead to the formation and destruction of a Passive film. In a potentiostatic experiment. the current density after 1200 sec in the Potential range of $-0.68\~-1.5\;V$ was low. This low current density indicates the protection potential range. Elongation at an applied potential of 0 V was high in this SSRT. However, corrosion protection under these conditions is impossible because the mechanical properties are worse owing to decreased strength resulting from the active dissolution reaction in parallel parts of the specimen. A film composed of $CaCO_3\;and\;Mg(OH)_2$ confers corrosion resistance. However, at potentials below -1.6 V forms non-uniform electrodeposition coating, since there is too little time to form a coating. Therefore, we concluded that the mechanical properties are poor because the effect of hydrogen gas generation exceeds that of electrodeposition. Comparison of the maximum tensile strength, elongation, and time to fracture indicated that the optimum protection potential range was from -1.45 to -0.9 V (SSCE).

F10/F12 분기기에서의 단면 형상별 주행안전성 연구

김성종(Sung Jong Kim),엄범규(Beom Gyu Eom),유원희(Won Hee Yoo),이희성(Hi Sung Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.6

현재 철도차량이 분기기 통과 시에 횡압의 변화가 최소화하는 설계가 요구되고 있다. 따라서 차량이 분기기를 통과하는 경우에 분기기에 작용하는 횡압 및 탈선계수를 예측하기 위하여 차량과 분기기간의 상호작용에 따른 동역학 해석을 수행하여야 한다. 본 연구에서는 분기기 단면 형상 변화가 차량의 주행안전성에 미치는 영향을 살펴보기 위해 포인트부, 크로싱부의 단면 형상 변화에 따른 주행안전성 해석을 수행하였다. F10/F12 분기기를 대상으로 포인트부 텅레일의 길이, 크로싱부 노즈레일의 높이를 변경시켜 주행안전성 해석을 수행하였다. When a vehicle passes through turnout, the design is required to minimize changes of lateral force. Therefore, In case the vehicle passed through the turnout, we ought to execute dynamic analysis of the interaction between the vehicle and the turnout in order to make an estimate of the lateral force and the derailment coefficient on the turnout. In this paper, we analyzed running safety by changing section shape of the point part and the crossing part in order to examine effect that changes of section shape reaches in running safety of the vehicle. Also, we analyzed the running safety by changing torque rail length of the point part or nose rail height of the crossing part on F10/F12 turnout.

고성능 씰리스 실린더의 해석 및 누설유량 시험

김성종(Kim sung-jong),김동수(Kim dong-soo),이승현(Lee seung-hyun) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4

The cylinder without seal has a piston with air bearing which is partly cylindrical and conical shape. The description of system geometry is deviation by the flow rate equation. Then pressure distribution and bearing force equations are derived. Several non-dimensional parameters are suggested. The relationship among bearing force, leakage flow and geometry of the bearing is investigated by simulation. And determination method for optimal design of sealless cylinder is given. A prototype of sealless cylinder which had rod bearing with four pockets, five pockets, and six pockets was built respectively. As a result of leakage flow test, it is evaluation to air bearing in sealless cylinder.

감귤 염색체 관찰 방법에 관한 연구

김성종(Kim Sung-Jong),김한용(Kim Han-Young),황재복(Hwang Jae-Bok),문덕영(Moon Duck-Young) 한국원예학회 1994 한국원예학회 학술발표요지 Vol.12 No.2

복숭아 우산식 지주시설 설치로 작업노력 절감

김성종(Sung Jong Kim),류명상(Myeong Sang Ryu) 한국원예학회 2009 한국원예학회 학술발표요지 Vol.2009 No.5

열충격을 받은 Graphite 재료의 열응력 해석

김성종(Sung-Jong Kim),이영신(Young-Shin Lee),김재훈(Jae-Hoon Kim),구송회(Song-Hoe Koo) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5

Graphite is a good conductor of electricity and a superior refractory, it has high thermal conductivity,<br/> high thermal shock resistance, excellent high temperature strength, excellent machinability, and a low modulus of elasticity. It is most expected to apply to rocket nozzle and spaceship etc. which is used under severe temperature conditions. However, thermal shock resistance and strength of graphite on high temperature have not been evaluated yet. In this study, the transient heat conduction and thermal stress analysis are performed through use of the finite element method with nonlinear code MSC.Marc. The thermal-mechanical analysis carried out, and the temperature and thermal stress contour of graphite are investigated. This result will be taken advantage of assist data for thermal shock experiment.

F10/F12 분기기에서의 가드레일 변화에 따른 주행안전성 해석

김성종(Kim, Sung Jong),엄범규(Eom, Beom Gyu) 한국도시철도학회 2013 한국도시철도학회논문집 Vol.1 No.1

기존선의 속도향상을 저해하는 요인은 매우 다양하지만 분기기 통과속도 제한규정은 그중 가장 대표적 사례로 손꼽히고 있다. 본 연구에서는 분기기에서의 속도향상을 목표로 대구 지하철공사 현장조사를 통한 분기기에서의 가드레일의 형상을 검토하였고, 개발한 분기기 해석기법을 통하여 F10/F12 분기에서의 가드레일 길이 변화에 따른 주행안전성 해석을 수행하였다. The speed-limit regulation on the turnout is the main cause which hinders the speed-up of conventional lines among many factors. The specification speed for the train which passes the turnout system is lower than that on the general track. In this paper, shape of guard rail of Daegu Metropolitan Transit Corporation was investigated, and the effect of the variation of guard rail length on the running safety of a vehicle was analyzed for the purpose of speed improvement on turnout using the developed analysis method.

복숭아 발육과정 중 품종별 당조성과 관련효소 활성의 변화

김성종(Sung Jong Kim),박혜영(Hye Young Park) 한국원예학회 2007 원예과학기술지 Vol.25 No.3

본 연구는 복숭아 주요 품종의 발육단계별 과실 생장 및 당대사 특성을 밝히고, 품종별 당조성과 당대사 관련 효소 활성의 변화와 이들의 상관을 구명하여 복숭아 과실의 당대사 기작을 밝히고자 하였다. 수확시기가 다른 복숭아의 4가지 품종의 종횡경 비(ℓ/D ratio), 전분함량과 산도는 시간의 경과에 따라서 감소하는 경향을 나타냈으며 이와는 반대로 당도와 총 수용성 당 함량은 수확기까지 계속 증가하는 경향을 나타냈다. 또한 생육 초기에 포도당과 과당이 높게 나타났으나 성숙기에 자당함량이 크게 증가하여 수확기의 중요한 당 조성 성분은 자당으로 나타났다. 복숭아 과실의 당 축적은 자당 합성효소와 자당 분해효소에 의하여 큰 영향을 받았으나 자당 인산화합성효소나 소르비톨 산화효소의 활성은 전 생육기간동안 전반적으로 낮은 활성을 나타냈다. 총 전분과 총 수용성 당은 부의 상관을 나타냈고, 당도와 총 수용성 당은 정의 상관을 나타냈다. 그러나 각 수용성 당과 당도의 상관은 품종에 따라서 다르게 나타나서 당도 증가에 직접적인 영향을 끼치는 수용성 당은 품종의 차이를 보였다. The purpose of this research was to assess the sugar accumulation and related enzyme activities of peach fruit during fruit development. Fruit growth and development patterns of ‘Kanoiwa Hakuto’ (an early maturing cultivar), ‘Nagazawa Hakuho’ (a medium maturing cultivar), ‘Yumyeong’ (a late maturing cultivar) and ‘Changhowon Hwangdo’ (a very late maturing cultivar) were similar. In all cultivars, soluble solid content (SSC) increased rapidly as the fruit matured. The contrast, titratable acidity increased gradually until pit hardening stage, and then decreased as the fruit matured. Total soluble sugar content in fruit increased with fruit maturation. The change was almost sigmoid and mainly due to the change in sucrose which was the predominant soluble sugar in mature fruits, although initially glucose and fructose were the predominant soluble sugars in immature stage. Activity of sucrose synthase (SS) was high in young fruit and decreased as the fruit matured. That of SS increased again to high level with fruit maturation in all cultivars. On the other hand, sucrose-phosphate synthase activity was low throughout fruit maturation. Thus SS might account for the most portion of sucrose synthesis. Acid invertase (AI) activity was high at the initial fruit growth, and decreased to low level at ripening. Since AI activity was high at the early developmental stage, content of reducing sugars such as glucose and fructose were higher than sucrose content. There was the negative correlation between total starch and total soluble sugar. Sucrose was positively correlated with SSC in all the cultivars, while glucose, fructose and sorbitol showed negative correlations with SSC.

북한 시장화와 사회적 자본

김성종(Kim, Sung-Jong) 충북대학교 국제개발연구소 2020 사회적경제와 정책연구 Vol.10 No.1

본 연구는 북한 시장화에 따른 사회구조 및 질서 변화를 사회적 자본의 관점에서 고찰하는 것을 목적으로 한다. 사회적 자본은 한 사회의 지배적 규범이나 가치체계의 특성을 거시적 관점에서 관찰할 때 발견할 수 있다. 사회적 자본의 핵심적 구성요소는 연결망, 규범, 신뢰이다. 시장화 이전 북한 사회의 대표적 연결망은 국가 또는 당 중심의 공식적 연결망이다. 공식적 연결망은 통제와 지시가 이루어지는 수직적이고 폐쇄적 연결망이었고 감시와 속박의 수단으로 기능했다. 연결망 구성원들은 상호 간 신뢰가 낮고 서로 무관심했다. 시장화 과정에서 거래와 교환을 목적으로 비공식적 연결망이 활성화되었다. 혈연적 연결망이 가장 기본이 되었고 다양한 연줄 관계가 형성되면서 자발성에 입각한 유기적 연대가 만들어지고 신뢰에 기반한 호혜성 규범이 생겨났다. 신뢰 대상에 대한 표준화가 이루어지고 신용거래가 등장하는 등 신뢰는 필수적 요소로 인식되었다. 북한 시장화 과정에서 등장한 연결망에 배태된 호혜성 규범이 사회 전반의 일반화된 호혜성으로 발전하지 못하고 있는 점이 현재 북한의 사회적 자본의 특성이라고 하겠다. The purpose of this study is to examine the changes in social structure and order due to the marketization of North Korea from the perspective of social capital. The key components of social capital are social networks, norms, and trust. The main social network of North Korean society before marketization was the official network of the one-party state. The formal network was a controlled, vertical-closed network that served as a means of monitoring and restraint. In the process of marketization, the kinetic network was the most basic, and various linkages were formed, resulting in spontaneous organic solidarity and trust-based reciprocity norms. Trust was recognized as an essential element with the standardization of trust targets and the emergence of credit transactions. It is North Korean social capital characteristics that have allowed the network that emerged from the process of marketization with embedded norms of reciprocity to develop without the development of generalized reciprocity in open society.

地方公共서비스 供給의 生產效率性 構造 分析

金聖鍾(Kim Sung-Jong) 한국지방자치학회 2000 韓國地方自治學會報 Vol.12 No.2

Various forms of Data Envelopment Analysis models were applied to investigate the productive efficiency in the provision of local public services in 70 Korean city governments. Technical efficiency scores and cost efficiency scores for each city governments were estimated. Major findings can be summarized as follows: (1) There are significant differences in technical efficiency between large city governments and small city governments, (2) Many city governments are operating in the increasing returns to scale technology, (3) In terms of inefficiency, technical inefficiency is more serious than cost efficiency. To reduce technical efficiency, government need to emphasize manpower training and organization restructuring.