• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.104-118
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• 2009

This study was carried out to classify Korean soybean varieties base on maturity group (MG) and to find character relationships according to planting date for high quality soybean seed production adapted to early season cultivation environment of Miryang. Results of maturity grouping of Korean soybean varieties showed that Keunol (3 cultivars), belonged to Group 0; Seonnok and Danmi in Group II, Shinrok in Group III, Seonyu (17 cultivars), in Group IV, Taekwang (44 cultivars) in Group V, Daewon (25 cultivars) in Group VI, and Kwangdu and Keumdu in Group VII. Agronomic characteristics of 100 soybean varieties were compared based on MG, cultivation year and seeding date. Soybean varieties belonging to the MG $VI{\sim}VII$ showed longer days to flowering and growth period, high lodging density and higher yield. Seed quality analysis revealed that as maturity was delayed, seed weight becomes heavier while seed cracks become abundant. In addition, occurrence of purple seed and phomopsis were higher in MG $0{\sim}III$. Protein content was higher in MG $0{\sim}III$, and isoflavone content was higher as maturity was delayed. On the other hand, lipid content was generally similar across MGs. Correlation analysis of major agronomic characters showed positive relationships between days to flowering and growth days, seed weight and lodging in MG $IV{\sim}V$, seed crack and growth days in MG $0{\sim}III$, seed crack and days to flowering in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and lodging in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and seed weight in MG $IV{\sim}V$ and MG $VI{\sim}VII$, purple seed and growth days in MG $IV{\sim}V$, purple seed and seed weight in MG $VI{\sim}VII$, phomopsis and growth days in MG $IV{\sim}V$ and MG $VI{\sim}VII$, and phomopsis and purple seed in MG $IV{\sim}V$ and MG $VI{\sim}VII$. In contrast, a negative relationship was observed between seed weight and lodging in MG $0{\sim}III$. Correlating yield and major characters revealed negative relationships between days to flowering and growth days in MG $0{\sim}III$ and MG $IV{\sim}V$, whereas positive relationships were obtained on MG $VI{\sim}VII$ seeded on April 30. Lodging, seed weight and seed crack were all negatively correlated with yield in the MG $IV{\sim}V$ and MG $VI{\sim}VII$. Soybean cultivars identified as adaptable to early season planting for production of high quality soy curd and fermented soybean paste were Seonyu, Kwangdu, and Soho while those suited for the manufacture of soybean sprouts were Sobaeknanul, Kwangan, Sowon, and Bosuk. Geomjeong 2 chosen as best for mixing with rice.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.230-233
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• 2008

Stainless steels are alloy steels with iron as the primary constituent and chromium, nickel, and manganese as principal alloying elements. In addition to automotive, construction, and transportation industries, stainless steels have a variety of applications in the food, chemical, and pharmaceutical industries. Some common products made from stainless steel are sinks, wash basins, kitchen vessels, and cutlery. Among ferritic stainless steels, type 409 can be cold-formed easily and are used for deep-drawn parts such as vessels for the chemical and food industries. In this study, forming analyses and experiments to prevent the occurrence of inferiority such as wrinkles, crack, and neck for automotive muffler part are carried out to save the optimal conditions during forming by modifying the blank size and shape, blank holding force etc.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.389-396
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• 2000

Fatigue behavior of shear joints between combined reinforced concrete(RC) and reinforced steel fiber concrete(RSFC) specimens has been experimentally investigated. Experimental parameters used are the amount of steel fiber and the type of shear joint. 6 specimens have been tested under static load, and 8 specimens have been subjected to the fatigue load in a range of 50% and 5 % of the ultimate static load. The purpose of this research is to propose an empirical formula for fatigue shear behavior of combined RC and RSFC structures on the basic of experimental result. It can be observed from experimental result that addition of steel fibers to concrete specimen increases the static ultimate load by approximately 25%, enhances the fatigue behavior, and also reduces vertical and lateral displacements at the shear joint for a given load cycle after the occurrence of first crack.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.431-441
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• 2014

The effects of hull-girder vibration on the fatigue strength of a Post-Panamax container ship are discussed in the present paper. Firstly, the short-term sea states are categorized according to the occurrence probability of each sea state. Time histories of hull-girder stress in short-term sea states are calculated by means of a nonlinear simulation code of ship response assuming that the hull-girder is rigid and flexible. Then, the calculated stress peaks are processed by the rainflow counting method, where two different counting procedures are used based on the considerations of crack propagation behaviors. Finally, the fatigue damage in life time of the ship in each categorized short-term sea state is estimated by means of Miner's rule. Based on the calculated results, the effects of hull-girder vibrations on the fatigue damage are clarified by disaggregated damage from short-term sea state.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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• pp.16-19
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• 2006

With the fast growth of the shipbuilding industry, the number of lifting lugs used every year has reached onehundred. This paper is aimed at examining the cause of cracking in the hopper top plate, due to block lifting. First of all, we have investigated the fracture surface in the occurrence position of the crack of the hopper top plate, using the scanning electron microscope. In this study, we have evaluated the structural strength for COT super block under present lifting conditions. For this purpose, the equivalent stresses have been calculated by linear elastic analysis, using the finite element program ABAQUS.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.55-57
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• 2012

In this study, the field applicability on reducing the heat of hydration of mass concrete by using the hydration heat difference method is analyzed with the following summary. As a result of applying the hydration heat difference method by using low heating combination, the temperature difference between the central part and the surface part of mass material was reduced, and as a result of visual observation, there was no showing of cracks by the hydration heat on the upper surface part. Therefore, the cracking index of the field to apply this method was shown to be approximately 1.57 with very little crack occurrence probability of less than 3%.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.508-513
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• 2003

The objective of this paper is to investigate the lining board's capacity by using the static loading test and fatigue test. Specimens that constitute the H & Channel type lining board are adopted. The test is to inspect the possibility of retrofit and efficiency, which is required to upgrade the structure's capacity and to examine the effects of the improvements of specimen by using structural analysis, stress analysis, static loading test and fatigue test, respectively. The accumulated test results of stress condition and deflection by bending will be used to analyze the relation between the cause of fatigue crack occurrence and the behavior of both structure system and the steel.

• Smart Structures and Systems
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• v.4 no.5
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• pp.517-530
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• 2008

This paper deals with civil infrastructures in general, sensor and smart structure technology, and smart steel structures in particular. Smart structures technology, an integrated engineering field comprising sensor technology, structural control, smart materials and structural health monitoring, could dramatically transform and revolutionize the design, construction and maintenance of civil engineering structures. The central core of this technology is sensor and sensor networks that provide the essential data input in real time for condition assessment and decision making. Sensors and robust monitoring algorithms that can reliably detect the occurrence, location, and severity of damages such as crack and corrosion in steel structures will lead to increased levels of safety for civil infrastructure, and may significantly cut maintenance or repair cost through early detection. The emphasis of this paper is on sensor technology with a potential use in steel structures.

• Journal of Welding and Joining
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• v.6 no.1
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• pp.21-27
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• 1988

This paper describes weldability of dissimilar metal plates with YAG laser for the use of a small-size electronic spring parts. Effects of welding conditions, combination of plates, thickness of upper plate are examined in relation to welding strength and microstructure of welded region. The obtained results are summarized as follows. Welding defects such as cavity and crack showed a tendency to easily occur in the case where 1) pulse duration is short, 2) laser power is high, 3) PBS plate with high thermal diffusivity is used for lower plate. Among these defects, the occurrence of cavity cased a drop of welding strength. This results from the reduction of welding area between upper and lower plates. In SK-5/SUS304 plates (thickness: 0.2/0.4mm/, welding strength was the highest in welding conditions: laser power is 30J/pulse, pulse duration 9ms, amount of defocus +2mm.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.458-461
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• 2006

Early age cracking of concrete is a widespread and complicated problem, and diverse applications in practical engineering have focused on this issue. Since massive concrete base slab composes the infrastructure of other concrete structures such as pier, concrete dam, and high rise buildings, early age cracking of that is considered as a crucial problem. In this study, finite element analysis (FEA) implemented with the age-dependent microplane model was performed. For a massive concrete base slab, cracking initiation and propagation, and deformation variation were investigated with concrete age. In massive concrete slab, autogenous shrinkage increases the risk of early age cracking and it reduces reinforcement effect on control of early age cracking. Gradual crack occurrence is experienced from exterior surface towards interior of the slab in case of combined hydration heat and autogenous shrinkage. FEA implemented with enhanced microplane model successfully simulates the typical cracking patterns due to edge restraint in concrete base slab.