• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.101-109
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• 1996

Two-dimensional lid-driven closed flows within square cavity were studied numerically for four Reynolds numbers : $10^4$, 3$\times10^4$, 5$\times10^4$ and 7.5$\times10^4$. A convective difference scheme to maintain the same spatial accurary by irregular grid correction is adopted by applying the interior division principle. Grid number is $80\times80$and its minimum size is about 1/400 of the cavity height. At Re=$10^4$, periodic migration of small eddies appearing in corner separation region and its temporal sinusoidal fluctuation are represented. At three higher Reynolds numbers(3$\times10^4$, 5$\times10^4$ and 7.5$\times10^4$), an organizing structure of four consecutive vorticles at two lower corners is revealed from time-mean flow patterns. But, instantaneous flow characteristics show very random unsteady fluctuation mainly due to the interaction between rotating shed vortices and stationary eddies within the corners.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.3
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• pp.217-232
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• 1992

A Numerical study on two-dimensional laminar natural convection with and without surface radiation in fully or partially open square cavity was performed. The cavity has one vertical heated wall facing a vertical opening and two horizontal insulated walls. The pressure boundary condition was applied to the opening instead of the velocity boundary condition. The results of this study showed that the increase of partition length decreased the convective and the radiative Nusselt numbers. It was also found that the increase of wall emissivity decreased the convective Nusselt numbers but increased the radiative Nusselt numbers.

• ETRI Journal
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• v.33 no.2
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• pp.163-168
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• 2011

A Fabry-Perot cavity (FPC) antenna producing both high-gain and circularly-polarized (CP) behavior is proposed. To increase antenna gain and obtain CP characteristics, a superstrate composed of square patches with a pair of truncated corners is placed above the linearly polarized patch antenna with an approximately half-wavelength distance from the ground plane at the operating frequency. The proposed antenna has the advantages of high gain, a simple design, and an excellent boresight axial ratio over the operating frequency bandwidth. Moreover, used in an FPC antenna, the proposed superstrate converts a linear polarization produced by a patch antenna into a circular polarization. In addition, the cavity antenna produces left-hand circular-polarization and right-hand circular-polarization when a patch antenna inside the cavity generates x-direction and y-direction polarization, respectively. The measured and simulated results verify the performance of the antenna.

• Proceedings of the Korean Magnestics Society Conference
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• 2001.10a
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• pp.118-119
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• 2001

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1149-1154
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• 2005

The finite difference lattice Boltzmann method(FDLBM) is a quite recent approach for simulating fluid flow, which has been proven as a valid and efficient tool in a variety of complex flow problems. It is considered an attractive alternative to conventional FDM and FVM, because it recovers the Navier-Stokes equations and is computationally more stable, and easily parallelizable to simulate for various laminar flows and a direct simulation of aerodynamics sounds. However, the research of a numerical simulation of turbulent flow by FDLBM, which is important to analyze the structure of turbulent flow in engineering fields, is not carried out. In this research, the FDLBM built in the turbulent model is applied, and a flowfield around 2-dimensional square to validate the applied model with 2D9V is simulated. Besides, 2D computation of the cavity noise generated by flow over a cavity at a Mach number of 0.1 and a Reynolds number based on cavity depth of 5000 is calculated. The computation result is well presented a understanding of the physical phenomenon of tonal noise occurred primarily by well-jet shear layer and vortex shedding and an aeroacoustic feedback loop.

• Korean Journal of Adult Nursing
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• v.17 no.2
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• pp.276-286
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• 2005

Purpose: The study is to investigate the effects of tea tree oil gargling on oral cavity micro-organism growth and on the perceived discomfort of patients receiving chemotherapy. Methods: A nonequivalent control group non-synchronized design was used to determine the effects of tea tree oil gargling on oral cavity for 20 second after using it for one week, twice a day. The sample consisted of two groups of patients receiving chemotherapy : 19 patients in experimental and 20 patients in control group. The instruments used in the study were Oral Assessment Guide(OAG), a measure of perceived symptoms on oral cavity, and a test of oral mucosal micro-organism culture. The data were analyzed using chi-square test, repeated measure of ANOVA, and Pearson correlation coefficient. Results: There was no significant difference between the two groups in micro-organism culture test of oral mucosa. The experimental group showed a lower number and fewer kinds of micro-organisms than the control group. Conclusion: It is considered that use of tea tree oil is effective in infection control of the oral cavity.

• Journal of Korean society of Dental Hygiene
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• v.6 no.4
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• pp.387-402
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• 2006

This research carried out a survey for 569 students in a junior college of jeollanamdo to provide a needful basic data in developing suitable health promotion program and creating a direction of the oral hygiene education process to intial adult population after holding the oral cavity health action and a affecting factors to it. A collected data obtained the following conclusion. According to school grade, a difference of action factor is Chi-square and Pearson's correlation coeficient in actionfactor and acknowledgement-perception factor and a step-by-step recurrence analysis processed a related factor of the oral health action. 1. A related action factor of the oral health appeared meaningful difference of the oral cavity medical examination, the oral cavity clean device use or not, dental surgery prevention cure or not among the third grade who had the most experience of the oral hygiene education within one year recently. 2. A significant of the oral cavity health acknowledged and perceived and a concern of the oral cavity health, acknowledged the oral cavity health state distribution are the highest in the third grade. 3. According to monthly income, a large income is higher than a small income about self-effects in a relation between the oral cavity health action and acknowledgement-perception factor. the average of a large income is 30.59(${\pm}5.79$). The obstacle of the oral cavity health action is 12.51(${\pm}3.19$). a large income is highest. according to school career, under middle school layer obtained the highest average 16.33(${\pm}3.53$). according to a school year, acknowledge-perception factor of the oral cavity health control of the third grade is the highest(38.81(${\pm}6.25$). 4. In mutual relation between acknowledge-perception factor and the oral cavity health action, a variable constants of meaningful mutual relation are the oral cavity health perception, self-effects, the oral cavity health action obstacle, the oral cavity health action benefit, the oral health action control, aggressive. and they are self-effects, the oral cavity health action in the oral cavity health perception. A significant of the oral cavity health and the oral cavity health action obstacle are the oral cavity health action benefit and the oral cavity health action control. 5. The affecting factors to the oral health action are self-effects, action factor, acknowledged the oral health control.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.503-513
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• 2018

The purpose of this study was to identify the effectiveness of oral care protocol including individual oral care education, cryotherapy and benzydamine gargling on oral cavity status and self-care performance in solid cancer patients receiving chemotherapy. Thirty-one patients were enrolled by convenience sampling in this study and allocated to control (n=18) and experimental group (n=13). In the intervention group, individual oral care education, oral cryotherapy and benzydamine gargling were applied, while the control group received pre-existed oral care. Oral cavity status and self-oral care behavior were measured in five periods. The data were analyzed using the Mann-Whitney test, Friedman test, and Chi-square test. There was no significant difference in oral cavity status between the groups. But the two groups showed the poorest oral cavity status on $14^{th}$ day. Self-care behavior was significantly higher in the intervention group than the control group. This effect had maintained for 4months after completion of study. The results showed that individual oral care education by oncology nurse is effective to encourage patients to do self-care behavior and a further study is needed to explore the effect of cryotherapy and benzydamine gargling on oral cavity status of patient with solid tumor.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.157-161
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• 2012

This work reports the stability of the resonant characteristics in multimode interferometer coupled square ring semiconductor cavities. Based on the analysis of single square ring cavities, the single mode operations in the multimode interferometer coupled ring cavities are analyzed and the devices are demonstrated on the semiconductor multiple quantum well epitaxial structure. By varying the lasing conditions such as substrate temperature and input pump power, single resonant mode operations are also observed.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.4
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• pp.28-37
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• 1993

Flow characteristics within the three-dimensional square cavity are studied experimentally by adopting PIV(Particle Image Velocimetry). A new method for tracking the same particle pairs in the consecutive flow image is suggested resulting in more effective acquisition of the velocity vectors. Two methods for supplying the shearing stress within the cavity are developed by continuous moving belt and 2-dimensional plane Poiseuille flow. The effect of TGL vortex in the case of belt-moving flow is remarkable owing to the distribution of the kinetic energy in the spanwise direction. But, for the plane Poiseuille flow, velocity profiles similar to a forced vortex are obtained and its tendency increases with the Reynolds number.