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Ultimate strength performance of Northern sea going non-ice class commercial ships
Park, Dae Kyeom,Paik, Jeom Kee,Kim, Bong Ju,Seo, Jung Kwan,Li, Chen Guang,Kim, Do Kyun Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.3
In the early design stage of ships, the two most important structural analyses are performed to identify the structural capacity and safety. The first step is called global strength analysis (longitudinal strength analysis or hull girder strength analysis) and the second step is local buckling analysis (stiffened panel strength analysis). This paper deals with the ultimate strength performance of Arctic Sea Route-going commercial ships considering the effect of low temperature. In this study, two types of structural analyses are performed in Arctic sea conditions. Three types of ship namely oil tanker, bulk carrier and container ship with four different sizes (in total 12 vessels) are tested in four low temperatures (-20, -40, -60 and $-800^{\circ}C$), which are based on the Arctic environment and room temperature ($20^{\circ}C$). The ultimate strength performance is analysed with ALPS/HULL progressive hull collapse analysis code for ship hulls, then ALPS/ULSAP supersize finite element method for stiffened panels. The obtained results are summarised in terms of temperature, vessel type, vessel size, loading type and other effects. The important insights and outcomes are documented.
Effect of Methylene Blue on Alpha-Adrenergic Agonists-Induced Vasoconstriction in Rat Aorta
Park, Jung Dae,Kim, In Kyeom,Kim, Choong Young 慶北大學校 醫科大學 1992 慶北醫大誌 Vol.33 No.1
흰쥐의 대동맥을 사용하여 methylene blue전처치가 아드레날린성 알파 효현제에 의한 혈관수축반응에 미치는 영향을 관찰하여 다음과 같은 결과를 얻었다 혈관내피세포가 존재할때는 혈관 내피세포를 제거했을 때에 비해 norepinephrine에 의한 최대수축에는 차이가 없었지만 adrenergic alpha-agonist인 phenylephrine에 의한 수축작용은 현저히 감소되었으며 adrenergic alpha2-agonist인 clonidine이나 guanabenz에 의한 수축작용은 나타나지 않았다. 한편, methylene blue전처치에 의해 혈관내피세포가 존재할때의 adrenergic alpha-agonists에 의한 수축작용은 methylene blue를 전처치 하지 않은 상태에서 혈관 내피세포를 제거했을때와 유사하였다. 그러나 혈관내피세포를 제거했을 때 methylene blue를 전처치하면 norepinephrine에 의한 최대수축은 감소되었고 clonidine과 guanabenz에 의한 최대수축은 증가되었으며 phenylephrine에 의한 최대수축은 별다른 차이가 없었다. 그러나 이러한 최대수축의 차이에도 불구하고 EC50에는 차이가 없었다. 이상의 결과로 미루어 보아 methylene blue는 혈관내피세포에서 유리되는 이완물질의 작용을 억제할 뿐 아니라, 평활근의 수축작용도 조절하는 것으로 생각된다. The effect of methylene blue on the contractile responses induced by some adrenergic alpha-agonists was examined in rat aortic ring preparations. In an intact endothelium, norepinephrine and phenylephrine to a much less extent produce increase in contraction dose-dependently in contrast to unresponsiveness to clonidine and guanabenz. By the removal of endothelium, EC_50 values for both drugs increased, and the unresponsiveness to clonidine and guanabenz unmasked. These phenomena were shown in intact endothelium with methylene blue pretreatment. In the denuded preparations, by pretreatment with methylene blue, the norepinephrine-induced contraction was diminished while the clonidine-and guanabenz-induced contractions were augmented. On the other hand, phenylephrine-induced contraction was not influenced. However, regardless of alteration of maximal contractions, methylene blue had no effect on the sensitivity of denuded tissues to all adrenergic agonists. These results suggest that methylene blue modulates the contractile responses of smooth muscle as well as inhibits the actions of endothelium-derived relaxing factors.
김대영(Dae-Young Kim),박형서(Hyung-Seo Park),김웅겸(Woong-Kyeom Kim),표창률(Chang-Ryul Pyo),김헌영(Heon Young Kim) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.3
최근 휴대폰은 스마트폰의 출연으로 다기능화가 요구되고 있으며, 각 보드의 전기적 신호를 연결시키는 커넥터는 필수 핵심 부품이 되었다. 커넥터는 많은 양의 전기신호를 처리하기 때문에 소형화, 협피치화가 필요하다. 하지만, 커넥터의 소형화 및 협피치화는 구조적 안전성을 저하시키며, 외부하중에 의한 접촉불량을 발생시킨다. 따라서 본 논문에서는 초소형 협피치 FPC 커넥터를 개발하기 위해 벤치마킹을 통한 초기설계안을 도출하였으며, 터미널 두께 0.2mm, 개수 50 개를 기준으로 하였다. 체결성능을 평가하기 위해 수치해석 모델을 구성하였으며, 다구찌 방법을 이용하여 형상 최적화를 수행하였다. 또한, 터미널의 한계수명을 예측하기 위해 피로해석을 수행하였으며, 체결 성능이 향상된 최종형상을 도출하였다. Recently, multi-functionalization (as in smart phones) has been in demand, and the connectors connecting the electrical signals of each board in a cellular phone have become key components. The miniaturization of these connectors is required to achieve a finer pitch design and enhance the electrical signal transfer capacity. However, the miniaturization of connectors reduces the structural safety, and a finer pitch design may cause contact problems under external impact. In this paper, a preliminary design for miniaturized, finer-pitch connectors is suggested for a product with 50 pins and a thickness of 0.2 mm. The assembly process of the FPCB (Flexible Printed Circuit Board) and connector was simulated to ensure the holding force between the two components and avoid overstressing. The design optimization process was performed with the Taguchi method. Fatigue analysis was also conducted to predict the fatigue life of the terminal, and the theoretical and experimental results were compared.
Nonvolatile Memory Characteristics of Double-Stacked Si Nanocluster Floating Gate Transistor
Kim, Eun-Kyeom,Kim, Kyong-Min,Son, Dae-Ho,Kim, Jeong-Ho,Lee, Kyung-Su,Won, Sung-Hwan,Sok, Jung-Hyun,Hong, Wan-Shick,Park, Kyoung-Wan The Institute of Electronics and Information Engin 2008 Journal of semiconductor technology and science Vol.8 No.1
We have studied nonvolatile memory properties of MOSFETs with double-stacked Si nanoclusters in the oxide-gate stacks. We formed Si nanoclusters of a uniform size distribution on a 5 nm-thick tunneling oxide layer, followed by a 10 nm-thick intermediate oxide and a second layer of Si nanoclusters by using LPCVD system. We then investigated the memory characteristics of the MOSFET and observed that the charge retention time of a double-stacked Si nanocluster MOSFET was longer than that of a single-layer device. We also found that the double-stacked Si nanocluster MOSFET is suitable for use as a dual-bit memory.
Effect of corrosion on the ultimate strength of double hull oil tankers - Part I: stiffened panels
Kim, Do Kyun,Park, Dae Kyeom,Kim, Jeong Hwan,Kim, Sang Jin,Kim, Bong Ju,Seo, Jung Kwan,Paik, Jeom Kee Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4
Age-related problems especially corrosion and fatigue are normally suffered by weatherworn ships and aging offshore structures. The effect of corrosion is one of the important factors in the Common Structural Rule (CSR) guideline of the ship design based on a 20 or 25 years design life. The aim of this research is the clarification of the corrosion effect on ultimate strength of stiffened panels on various types of double hull oil tankers. In the case of ships, corrosion is a phenomenon caused by the ambient environment and it has different characteristics depending on the parts involved. Extensive research considering these characteristic have already done by previous researchers. Based on this data, the ultimate strength behavior of stiffened panels for four double hull oil tankers such as VLCC, Suezmax, Aframax, and Panamax classes are compared and analyzed. By considering hogging and sagging bending moments, the stiffened panels of the deck, inner bottom and outer bottom located far away from neutral axis of ship are assessed. The results of this paper will be useful in evaluating the ultimate strength of an oil tanker subjected to corrosion. These results will be an informative example to check the effect of ultimate strength of a stiffened panel according to corrosion addition from CSR for a given type of ship.
Effect of corrosion on the ultimate strength of double hull oil tankers - Part II: hull girders
Kim, Do Kyun,Park, Dae Kyeom,Park, Dong Hee,Kim, Han Byul,Kim, Bong Ju,Seo, Jung Kwan,Paik, Jeom Kee Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4
Numerous oil tanker losses have been reported and one of the possible causes of such casualties is caused by the structural failure of aging ship hulls in rough weather. In aging ships, corrosion and fatigue cracks are the two most important factors affecting structural safety and integrity. This research is about effect on hull girder ultimate strength behavior of double hull oil tanker according to corrosion after Part I: stiffened panel. Based on corrosion data of Part I (time-dependent corrosion wastage model and CSR corrosion model), when progressing corrosion of fourtypes of double hull oil tankers (VLCC, Suezmax, Aframax, and Panamax), the ultimate strength behavior of hull girder is compared and analyzed. In case of the ultimate strength behavior of hull girder, when occurring corrosion, the result under vertical and horizontal bending moment is analyzed. The effect of time-dependent corrosion wastage on the ultimate hull girder strength as well as the area, section modulus, and moment of inertia are also studied. The result of this research will be useful data to evaluate ultimate hull girder strength of corroded double hull oil tanker.