• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.91-98
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• 2014

For the purpose of designing and applying the optimum surge protection scheme, multi-stage coordinated surge protective device(SPD) system is suitable to successfully fulfill its tasks; first, to divert a large amount of the transient energy, second, to clamp the overvoltage to the level below the withstand impulse voltage of the equipment to be protected. The length of SPD connecting leads shall be as short as possible. Long connecting leads will degrade the protection effect of SPDs. In this paper, the influences of the length of connecting leads on the energy sharing in a coordinated SPD system were investigated experimentally, and the simulation of determining the energy sharing and protection voltage level of each SPD depending on the length of connecting leads was carried out by using P-spice program. It was confirmed that the protection voltage level and energy sharing in coordinated SPD systems are strongly influenced by the length of connecting leads.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.118-124
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• 2017

To investigate and analyze the cause of the failure of the connecting rod bolt and the crank pin bearing bolt of the diesel engine of this study, the following results were obtained through site surveying, the investigation of literature referring to similar failures, testing and inspection of the fracture surface, and the experience of the researchers. The fractured crank pin bearing bolt of the diesel engine is estimated to be damaged later than the connecting rod bolt. From the shape of fracture surface, it is evident that the failed connecting rod bolt is fractured by fatigue failure due to abnormally repeated loads (e.g. loosening of the connecting bolt, etc.), and is not failed by brittle fractures due to the impact load. The surface of the U-nut on the fractured connecting rod bolt has been worsening due to the improper use of lubricant (agent for prevention of thread fixing) and no usage of separating the each connecting rod on each cylinder. Moreover, there is the possibility that those poor surface conditions of the fractured connecting rod bolt have affected the failure of the connecting rod bolt of the main engine. And it could be assumed that the mechanical characteristic and manufacturing process of the failed connecting rod bolt and crank pin bearing bolt, which were made by a domestic company, conform to the design requirements for those bolts.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.393-399
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• 2017

In a reciprocating compressor, the piston and connecting rod are important parts. Excess mechanical stress on these parts may cause damage, and broken parts are expensive and difficult to replace. Therefore, it is necessary to analyze the mechanical stress affecting durability and longevity. The main purpose of this study was to identify locations of maximum stress on pistons and connecting rods. Based on dynamic calculation of the working process of a specific air compressor, an analysis of piston and connecting rod performance has been completed. A three-dimensional model for the air compressor's pistons and connecting rods was built separately, and FEM analysis of these components was carried out using a numerical method. The pistons were loaded by pressure which was changed according to crankshaft angle without thermal boundary conditions. The simulation results were used to predict and estimate stress concentration as well as the value of this stress on pistons and connecting rods. The maximum equivalent stress calculated are over 190 MPa on pistons and 123 MPa on connecting rods at crank angle $135^{\circ}$ and $225^{\circ}$ but these are under tensile yield strength. Besides, the calculated safety factors of connecting rods and pistons is higher than 1. Moreover, the results obtained can be used to provide manufacturers with references to optimize the design of pistons and connecting rods for reciprocating compressors.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.117-130
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• 2007

Incheon International Airport has handled 3,054,485 transfer passengers (11.9% transfer rate) and 950,441 transfer cargo(44.2% transfer rate)recorded in 2005. Comparing to 30-40% transfer passenger rate which are competition hub airports in northeast Asia, transfer passenger rate of Incheon International Airport is lower. Above all, We think that Minimum Connecting Time(MCT) which is relating factors with transfer rate need to be monitored to make up for the weak points in the current Incheon internationalairport system. Minimum Connecting Time is defined the legally minimum time necessary to change planes at a given airport. and Transfers represent 35% of the total passenger volume at Vienna International Airport in Europe, which underscores our function as a major international hub. Vienna is rated priority in reservation systems because of our excellent minimum connecting time, and that increases the sale of tickets through our airport. In 2004 the total number of transfer passengers rose 18% to 5,089,624. Short routes, a one roof concept and an outstanding logistics system make Vienna an ideal airport for transfers. This transfer-friendly one roof concept will also form the basis for the new VlE-Skylink Terminal. In case of Japan, Star Alliance has also implemented its so called "Move under one roof"concept at the new Centrair airport. All member carriers are located in the same part of the termina1, sharing check-in counters and ticketing facilities. Star Alliance member carriers can now offer customersa reduced average minimum connecting time of one hour, for transfers between international and domestic. The research purpose of the Study on the Enhancement for Minimum Connecting Time of Incheon International Airport is to increase transfer rate of passenger and cargo of Incheon International Airport at Northeast Asia through this paper.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.161-169
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• 2012

In general, Euclidean minimum spanning tree is a tree connecting input nodes with minimum connecting cost. But the tree may not be optimal when applied to real world problems of three dimension. In this paper, three dimension Euclidean minimum spanning tree is proposed, connecting all input nodes of 3-dimensional space with minimum cost. In experiments for 30,000 input nodes with 100% space ratio, the tree produced by the proposed method can reduce 90.0% connection cost tree, compared with the tree by two dimension Prim's minimum spanning tree. In two dimension plane, the proposed tree increases 251.2% connecting cost, which is pointless in 3-dimensional real world. Therefore, the proposed method can work well for many connecting problems in real world space of three dimensions.

• Korean Journal of Veterinary Research
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• v.14 no.2
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• pp.159-171
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• 1974

Histological and histochemical studies were made on the lining epithelia of the various ducts in epidymis of the Rooster and absorptive function of the canal epithelial cells in the Rooster epididymis were also investigated after administration of India ink. The results obtained were summerized as follows; 1. Epihtelium lining the rate testis was mainaly composed of single later of cuboidal cells, and was partially composed of flattened squamous or low columnar cells. Efferential ductules were characterized by having many villous projections orrfolds which extened into the lumen, and were lined by stereociliated pseudostratified epithelium which consisted of manily ciliated columnar cells, a few scattered clear cells and basal cells. Connecting ductules were lined by ciliated pseudostriatified colummnar epithelium in which ciliated columnar cells, clear cells and basal cells were noted. Epididymal ducts were lined by pseudostratified epidhelium in which columnar and basal cells were noted. 2. PAS-granules, saliva resistant were noted mainly in the epithelial cells of efferential and connecting ductules. 3. Sudan black B stained heavily the granules in the epithelial cells of sufferential and connecting ductules. 4. The granules reactive to acid phosphatase most abundant in the epithelial cells of efferential ductules and were lesser amount in the epithelial cells of connecting ductules where as very few or no granules were seen in the rest of the ducts. 5. Alkaline phosphatase activity was most prominent but discontinuous in the luminal surface of the epithelium of efferential ductules and less marked in the connecting ductless. No enzyme activity was noted in the canal epithelium of epididyml duct. 6. India ink granules were most numerous in the epithlial cells of efferential ductules and were a few in connecting ductules. Very few or no granules of India ink were noted in the other types of the ducts. India ink granules in the epithelium increased gradually as the time after the administration of India ink (one up to twenty-nine hours) has proceeded. From those results it is suggested that epithelial cells of efferential and connecting ductules have active absorptive function, whereas the rest of duct system in the epididymis of the Rooster may be the mere pathway of the seminal fluid without significant modification of its constituents.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.101-107
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• 1998

This paper is studied micro-defect characteristics by phosphorus 1MeV ion implantation and Rs, SRP, SIMS, XTEM for the RTA process was measured and simulated. As the dose is higher, the Rs is lower. When the dose are $1{\times}10^{13}/cm^2,\;5{\times}10^{13}/cm^2,\;1{\times}10^{14}/cm^2$, the Rp are $1.15{\mu}m,\;1.15{\mu},\;1.10{\mu}m$ respectively. As the RTA time is longer, the maximum concentration position is deeper from the surface and the concentration is lower. Before the RTA was done, we didn't observe any defect. But after the RTA process was done, we could observe the RTA process changed the micro-defects into the secondary defects. The simulation using the buried layer and connecting layer structure was performed. As results, the connecting layer had more effect than the buried layer to latch-up immune. Trigger current was more $0.6mA/{\mu}m$ and trigger voltage was 6V at dose $1{\times}10^{14}/cm^2$ and the energy 500KeV of connecting layer Lower connecting layer dose, latch-up immune characteristics was better.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.251-262
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• 1999

The assemblage of the trapezoidal segments, which is being used increasingly to shield tunnelling, with Guide rod and Dowel forms tunnel lining. In this case the larger the taper angle of trapezoidal segment is, the easier the assembly work becomes. The large angle can reduce the water proof material's phenomenon of being pushed back, but decreases the structural safety in connecting section of tunnel lining. In this paper a 3-dimensional numerical analysis was performed to estimate the exact behavior of a model shield tunnel made by connecting 3-dimensionally various accessories with irregular sectioned segments. We obtained the operating force of connecting section according to the change of taper angle of trapezoidal segment and sought for improved scheme for connecting section by comparing and analyzing the test results on the friction resistance force of connecting parts.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.142-147
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• 2014

Finite element analysis along with DOE scheme has been performed to obtain robust design of connecting rod assembly. An analysis was conducted with five loading steps. Fatigue analysis was done using commercial software FEMFAT and fatigue safety factors at the interested regions such as shank area of small end and big end were calculated. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Each case is simulated to find the most influential factors. Response for this study, maximum Von-Mises stress, has been used to determine main factors of connecting rod assembly. Among the 3 factors, compression load affected the response greatly. However, bolt assembly load and width of shank flat area showed a little influence to the response. Interaction effects among factors considered did not occur. Connecting rod assembly considered in this study showed its sensitivity to the noise factor such as compression load rather than design factor such as width of flat shank area.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.716-723
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• 2016

A connecting rod is a crucial part for transmitting an explosive force to the crankshaft in the engine. Stress concentration in connecting rod due to the accumulation of the repeated load may initiate micro crack and result in a crucial break down of the component. Two approaches are adopted to obtain a robust design of connecting rod. Inner and outer array matrix based on combinations of control factors and noise factors are constructed for using Taguchi method. Calculated stress results for each element of matrix are plotted in the Goodman diagram. Robust design approach by Taguchi method reduces stress concentration occurred in small end fillet area of the default model. Variable stress approach using Goodman diagram also confirms a robust design by Taguchi method.