• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.241-247
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• 2005

The aim of this study was to develop a trawl escapement device which can improve the survival rate of young fishes passed through trawl codend. The sea experiments according to the bar space of the device and bar materials were carried out to decide the bar space and device materials in Korean southern sea and off Cheju island. Stainless pipes and MC bars were used to test the efficiency of escapement device materials. Although escapement rates of MC bar for main species were a little higher compare with stainless pipe, the efficiency of device for stainless pipe was better than MC bar. Escapement devices of sort-K type and grid panel type were also compared. Escapement rates of redlip croaker(Pseudosciaena polyactis), blackthroat seaperch(Doederleinia berycoides) and finespotted flounder (Pleuronichthys cornutus) showed 61.7%, 2.0% and 2.7% on the sort-x type and 69.9%, 1.1% and 2.0% for the grid panel type but the difference was little. Fishes under 20mm head width and fishes which swimming speed is so slow compared with body length could not go through well the device. Escapement rates according to the bar space were estimated using grid panel type. The rates of redlip croaker(Pseudosciaena polyactis) for the bar space of 20mm, 25mm, 35mm were increased as 60.3%, 61.0% and 77.8%, and 9.8%, 16.4% and 45.6% for horse mackere1(Trachurus japonicus), respectively.

• Membrane Journal
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• v.7 no.2
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• pp.75-83
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• 1997

The disc plate and frame type modules for reverse osmosis were developed using three different types of baffles: linear (Type 1), curved (Type 2) and parallel shapes (Type 3). Separation performance tests were carried out for the modules using NaCl and sucrose solutions under the various concentrations and operating pressures. The permeation flux and solute rejection ratio for Type 3 module were the highest within operating pressure (35bar) and flow rate (6 l/min). The flux improvement ratio of Type 2 or 3 to Type 1 for NaCl solution decreased as operating pressure increased: flux improvement ratios of Type 3 for 1wt% of NaCl solution were about 100 and 10% at 10 and 35bar, respectively. However, the flux improvement ratio for sucrose solutions varied with the operating pressure and concentration. The permeation flux for Type 3 depended on the flow rate linearly, which is higher than that of turbulent flow region in the smooth channel.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.73.1-73.1
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• 2012

We use hydrodynamic simulations to study the physical properties of gaseous structures in barred galaxies and their relationships with the bar strength. We vary the bar mass fbar relative to the spheroidal component as well as its aspect ratio. We derive expressions for the bar strength Qb and the radius where the maximum bar torque occurs. When applied to observations, these expressions suggest that bars in real galaxies are most likely to have fbar = 0.25-0.5. Dust lanes approximately follow one of x1-orbits and tend to be more straight under a stronger and more elongated bar. A nuclear ring of a conventional x2 type forms only when the bar is not so massive or elongated. The radius of an x2-type ring is generally smaller than the inner Lindblad resonance, decreases systematically with increasing Qb, evidencing that the ring position is not determined by the resonance but by the bar strength. Nuclear spirals exist only when the ring is of the x2-type and sufficiently large in size. Unlike the other features, nuclear spirals are transient in that they start out as being tightly-wound and weak, and then due to the nonlinear effect unwind and become stronger until turning into shocks, with an unwinding rate higher for larger Qb.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.401-406
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• 2016

Implant overdenture exhibits higher retention, masticatory function, and patient's satisfaction compared to conventional dentures. Particularly, in treatment of severe alveolar bone resorption, implant overdenture can be considered as the first treatment option. The types of attachments used for implant overdenture can be classified into solitary type, which implants are not connected to each other, and bar type in which implants are connected. In the case of solitary type commonly used in clinical practice, parallel relationship is important. When it is not established, there is a higher risk of attachment wear, retention loss, and frequent visits for maintenance. In this case, satisfactory results have been obtained with implant overdentures using milled bar on two unparallel implants placed on the mandible.

• Honam Mathematical Journal
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• v.29 no.2
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• pp.213-222
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• 2007

A Weyl type algebra is defined in the paper (see [2],[4], [6], [7]). A Weyl type non-associative algebra $\bar{WN_{m,n,s}}$ and its restricted subalgebra $\bar{WN_{m,n,s_r}}$ are defined in the papers (see [1], [14], [16]). Several authors find all the derivations of an associative (Lie or non-associative) algebra (see [3], [1], [5], [7], [10], [16]). We find Der($\bar_{WN_{0,0,1_n}}$) of the algebra $\bar_{WN_{0,0,1_n}}$ and show that the algebras $\bar_{WN_{0,0,1_n}}$ and $\bar_{WN_{0,0,s_1}}$ are not isomorphic in this work. We show that the associator of $\bar_{WN_{0,0,1_n}}$ is zero.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.31.3-31.3
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• 2017

The presence of a bar in disk galaxies indicates that galaxies reached their dynamical maturity, and secular evolution has started to play key roles in the evolution of disk galaxies. Numerical simulations predicted that as a barred galaxy evolves, the bar becomes longer by capturing its immediate neighbor disk stars. We test the hypothesis by exploring bar lengths and measuring the light deficit around the bar at various redshift. Supplementing already classified barred galaxies in later type disk galaxies ($$T{\geq_-}2$$, Sheth et al. 2008), we classify barred galaxies among earlier type disk galaxies (T<2) up to z~0.8 using F814W images from the Cosmic Evolution Survey (COSMOS). We estimate the length of bars analytically for ~400 galaxies, and find that there is a slight decrease in bar length with redshift. We also find that longer bars show more prominent light deficit around the bar and this trend is stronger for nearby galaxies. Our results are consistent with the predictions from numerical simulations, and imply that the bar induced secular evolution is already in place since z~0.8. 

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.199-205
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• 2001

This paper describes the design methodology, manufacturing process, rebar tensile and bending properties. Braidtrusion is a direct Composite fabrication technique utilizing an in-line braiding and pultrusion process. The produced Composite rebar exhibits ductile stress-strain behavior similar to that of conventional steel bar. Various rebar diameters ranging from modeling scale(3m) to full-scale prototype of 9.5mm have been produced Glass Fiber Reinforced Plastics(GFRP) rebar were successfully fabricated at $\phi$8.5mm and $\phi$9.5mm nominal diameters of soild and hollow type using a braidtrusion process. Tensile and bending specimens were tested and compared with behavior of stress-strain of GFRP rebar and steel bar.

• Honam Mathematical Journal
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• v.24 no.1
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• pp.75-86
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• 2002

A Nielsen number $\bar{N}(f:X-A)$ is a homotopy invariant lower bound for the number of fixed points on X-A where X is a compact connected polyhedron and A is a connected subpolyhedron of X. This number is extended to Nielsen type numbers $\bar{NP_{n}}(f:X-A)$ of least period n and $\bar{N{\phi}_{n}}(f:X-A)$ of the nth iterate on X-A where the subpolyhedron A of a compact connected polyhedron X is no longer path connected.

• Communications of the Korean Mathematical Society
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• v.34 no.2
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• pp.615-632
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• 2019

We study generic lightlike submanifolds M of an indefinite trans-Sasakian manifold ${\bar{M}}$ or an indefinite generalized Sasakian space form ${\bar{M}}(f_1,f_2,f_3)$ endowed with an $({\ell},m)$-type metric connection subject such that the structure vector field ${\zeta}$ of ${\bar{M}}$ is tangent to M.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.2
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• pp.14-21
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• 2009

The typical hydraulic hoisting system of the rack-bar type sluice gate is composed of a hydraulic supply unit using an uni-directional pump, a direction control valve, a hydraulic motor, a counter balance valve, and flow control valves. Here, the hydrostatic transmission is applied to the hoisting system of rack-bar type sluice gate to simplify the operation of gate such that the upward and downward direction of gate is simply controlled by the direction of pump rotation. The new hydraulic hoisting system is composed of a bi-directional pump, a hydraulic motor, two counter balance valves, two check valves, two pilot-operated check valves, two relief valves and a shuttle valve. The characteristics of a suggested system are analyzed by computer simulations.