• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.360-367
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• 2003

Diamond-like carbon(DLC) films are considerable research interest because of their widespread applications as protective coatings in areas such as optical windows, magnetic storage disks, car parts, biomedical coatings and as micro-electromechanical devices(MEMs). DLC films were deposited on WC-Co by PECVD using Ar, $C_2H_4$ gas. Tribological tests were conducted using a ball-on-disk type tribometer in dry air. Three kinds of counter-bodies balls were used. The counter-bodies balls are SM45C, SUJ2 and $ZrO_2$(3.17mm in diameter). Wear rate of the samples were calculated after measuring the worn-out volume of the wear track. As results wear test, the higher hardness of counter-bodies, friction coefficient low. As result of XPS estimation, wear debris generated as an oxide lower the friction coefficient.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.27-31
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• 2013

The structure of a variable liquid column oscillator(VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system for absorbing the high kinetic energy of the accelerated motions of multiple floating bodies using an air-spring effect produced the installation of inner air chambers. Thus, a VLCO can improve the energy efficiency of the activating object type of wave energy converters made by the Pelamis Company. In this research, an experiment was performed in two cases: with the top valves closed and open. The floating bodies were connected by hinges. The effect of the internal flow was estimated by comparing the results for the closed and open valves.

• Korean Journal of Veterinary Research
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• v.59 no.1
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• pp.25-31
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• 2019

The aim of this study was to determine predictive risk factors implicated in complications in dogs with esophageal foreign bodies. Medical records of 72 dogs diagnosed with esophageal foreign bodies by endoscopy were reviewed retrospectively. Factors analyzed included age; breed; gender; body weight, location, dimension, and type of foreign body; and duration of impaction. To identify risk factors associated with complications after foreign body ingestion, categorical variables were analyzed using the chisquare or Fisher's exact tests and multivariate analysis, as appropriate. Complications secondary to esophageal foreign body ingestion included megaesophagus, esophagitis, perforation, laceration, diverticulum, and pleuritis. Univariate analysis revealed that the location and duration of impaction after foreign body ingestion were associated with an increased risk of esophageal laceration and perforation. Multivariate analysis showed that age, duration of impaction, and foreign body dimension were significant independent risk factors associated with the development of complications in dogs with esophageal foreign bodies. In conclusion, these results showed that longer duration of impaction and larger foreign body dimensions may increase the risks of esophageal laceration, perforation, and plueritis in dogs.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.5
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• pp.11-20
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• 2018

To prevent illegal building work in advance, regional building safety centers were introduced to perform technical investigations and management. The purpose of this study is to propose the detailed operational directions of the regional building safety center through the analysis on the current status of parameters, such as the operation of designated confirmation and inspection bodies in Japan. We consider the role, building administrative process and establishment criteria of regional building safety centers through the analysis the introduction background and the designation criteria of designated confirmation and inspection bodies. In establishing the center's professional manpower qualifications, we refer to the criteria for the professional qualifications of the designated confirmation and inspection bodies. In addition, the calculation method of required manpower of verification inspectors in Japan was used as a reference in setting the scale of regional professional manpower. Finally, we propose the detailed operational directions of the regional building safety center such as (1)roles of the center, (2)establishing management plan of the center, (3)work scope (4)scale of the professional manpower, (5)qualification of the professional manpower, and (6)funds.

• Structural Engineering and Mechanics
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• v.58 no.3
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• pp.555-576
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• 2016

In this paper an efficient approach is introduced for design and analysis of double-layer grids including both geometrical and material nonlinearities, while the results are compared with those considering material nonlinearity. Optimum design procedure based on Enhanced Colliding Bodies Optimization method (ECBO) is applied to optimal design of two commonly used configurations of double-layer grids. Two ranges of spans as small and big sizes with certain bays of equal length in two directions are considered for each type of square grids. ECBO algorithm obtains minimum weight grid through appropriate selection of tube sections available in AISC Load and Resistance Factor Design (LRFD). Strength constraints of AISC-LRFD specifications and displacement constraints are imposed on these grids.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.113-124
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• 1984

The dynamic response of vertically axisymmetric floating bodies is numerically calculated with corrections of Fenton's coefficient matrix. The computational effort required is considerably reduced due to axisymmetry of the bodies. Comparisons are made with the results of Hoffman's model tests of the discus buoy. In the near future, this study will be applied to calculate the dynamic response of large scale structures, located in the deep sea, i.e., tension leg platforms.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.245-256
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• 2002

Two-dimensional formulations for wind forces on elongated bodies, such as bridge decks, are reviewed and links with expressions found in two-dimensional airfoil theory are pointed out. The present research focus on indicial lift responses and admittance functions which are commonly used to improve buffeting analysis of bluff bodies. A computational fluid dynamic (CFD) analysis is used to derive these aerodynamic functions for various sections. The numerical procedure is presented and results are discussed which demonstrate that the particular shapes of these functions are strongly dependent on the evolution of the separated flows around the sections at the early stages.

• Mycobiology
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• v.38 no.4
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• pp.282-285
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• 2010

Cordyceps cardinalis successfully produced its fruiting bodies from multi-ascospore isolates. However, subcultures of multiascospore isolates could not produce fruiting bodies after few generations. Fruiting body production also differed from sector to sector of the same isolate. Single ascospore isolates were then co-inoculated in combinations of two to observe the fruiting characteristics. Combinations of certain isolates produced perithecial stromata formation, whereas other combinations did not produce any fruiting bodies. These results show that C. cardinalis is a heterothallic fungus, requiring two isolates of opposite mating types for fruiting body production. It was also shown that single ascospore isolates are hermaphrodites.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1658-1667
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• 1993

In this research, a numerical algorithm has been developed, which can be applied to the large deformation and large displacement contact problems between two deformable bodies. The contact conditions expressed in terms of the rate of angle change have been proposed considering the change in geometric shape and rate of contact force. A set of linear simultaneous equations is constructed by adding the geometric shape change and contact conditions to the original stiffness matrix. A new method to determine time increment has been proposed based on Euler method, in which the condition to prevent the contact bodies from penetrating and overrunning each other has been taken into consideration. Practical application to contact problem is extrusion in which bodies are sliding along the contact boundary.

• Journal of the Korean Institute of Navigation
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• v.10 no.1
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• pp.129-138
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• 1986

A matrix partitioning method is proposed for the 2-D motion analysis of floating bodies. For the numerical solution, the boundary of a floating body is approximated with a series of line segments and the governing integral equation is transformed into a system of linear equations. A new solution procedure of resulting linear equation with complex coefficients is formulated and programmed using a matrix partitioning scheme and the Choleski decomposition. From the case study, it is found that the proposed method is efficient in the motion analysis of floating bodies, especially in the calculation of hydrodynamic coefficients. Also, it requires smaller memory size and less computing time compared with conventional methods.