• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.541-549
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• 2000

The present study experimentally investigated the effect of refrigeration oil on the condensation heat transfer for R-407C and R-22 in a microfin tube with a U-bend. POE oil ($74.1\;\textrm{mm}^2/s,\;40^{\circ}C$,) and mineral oil $62.5\;\textrm{mm}^2/s,\;40^{\circ}C$,) were used for R-407C and R-22 respectively Experimental parameters were an oil concentration from 0 to 5%, a mass flux from 100 to $400kg/m^{2}s sand an inlet quality from 0.5 to 0.9. The enhancement factors for both R-22 and R-407C refrigerants at the first straight section decreased continuously as the oil concentration increased. They decreased rapidly as the mass flux decreased and the inlet quality increased. The heat transfer coefficients in the U-bend showed the maximum at the $90^{\circ}$/TEX> position. The heat transfer coefficients at the second straight section within the dimensionless length of 48 were larger by a maximum of 33% than the average heat transfer coefficient at the first straight section.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.173-178
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• 2001

The cost on transmission and election of precast concrete members largely depends on the weight of them. In this study, the weight of prestressed precast beam could be reduced by control the section and prestressing force to meet the required strength on the basis of the optimum process. The top and bottom concrete stress of the section considered is required to check according to each construction step for this process. The original rectangular beam weight could be reduced up to 50~39% due to the development of a U-beams from the optimum process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.883-884
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• 2011

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.441-452
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• 2014

In this paper, steel reinforced concrete(SRC) column and composite beam connections were statically tested under gravity loading. The composite beam consists of H-section and U-section members. Five full-scaled specimens were designed to investigate the effect of a number of parameters on behavior of connections such as H-section size, the presence of stud connector, the presence of stiffeners and top bars. In addition, structural performance of welded joint between the H-section and the U-section members is mainly discussed, with an emphasis on initial stiffness, strength, deformation capacity.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.565-574
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• 2004

The purpose of this paper was to investigate the block shear and the fracture in the net section, according to AISC Specifications, by analysing the shear lag effect in the block shear rupture of the single angle with three or four bolt connection. Specimen with three or four bolt connections showed that failure generally went from block shear with some net section failures to classic net section failures. From the test results, showed that the connection length, the thickness of angle, and reduction factor, which affect the block shear rupture, were investigated. According to the test results, it is suggested that the calculation of the net section rupture capacity by using the reduction factor of U, that was suggested by Kulak, is needed.

• Journal of Haehwa Medicine
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• v.19 no.1
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• pp.129-142
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• 2010

Objectives : The aim of this study was to show the rationale of point-selection for acupuncture and moxibustion in "the Urine"section(in the Naegyeong Chapter) of "the Dong-Ui-BO-Gam". Methods : First, We reviewed the causes of each disease in "the Urine" section of the "Dong-Ui-BO-Gam". Then, We explained the rationale of acupoint-selection for the treatment of those diseases referring to etiology and physiology of Oriental medicine, other applications of each acupoints in the "Dong-Ui-BO-Gam", characteristic of each acupoints, flow of Gi (Qi) through meridian pathways and specific acupoints etc. Results : There are comments on acupuncture and moxibustion for dysuria, urinary frequency, incontinence of urine, urethral pain, turbid urine, erythroid urine, cystitis of women, urethral pain of women in the Urine section of the "Dong-Ui-BO-Gam". Conclusions : Conception vessel and Kidney meridian are preferably used for acupuncture and moxibustion in "the Urine" section of the "Dong-Ui-BO-Gam". CV4(Kwanwon) is most frequently used and Sp9($\bar{U}$mn$\bar{u}$ngch'$\breve{o}$n), SP6(Sameumgyo), Liv1(Taedon) are also used often.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.949-954
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• 2013

Generally, structural plates under axial compression should be stiffened by longitudinal stiffeners in order to enhance the buckling strength. Though U-shaped ribs would be more efficient for the stiffened plate system, there is in the absence of a proper design guides or relevant research results. Thus this study is aimed to examine the local buckling behavior of stiffened plates with U-section ribs. 3-dimensional analysis models which include 3 types of U-shaped longitudinal stiffeners were simulated by using the finite element code ABAQUS. The bifurcation analysis were conducted and then the buckling analysis results are compared with the theoretical equation values. It is found that the rotational constraint effect provided by the U-ribs should increase the local buckling strength. Some features drawn from a series of parametric study results are summarized.

• Ocean Systems Engineering
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• v.11 no.1
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• pp.83-97
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• 2021

The submerged U-shape breakwater interaction with the solitary wave is simulated by the Boussinesq equations using the finite-difference scheme. The wave reflection, transmission, and dissipation (RTD) coefficients are used to investigate the U-shape breakwater's performance for different crest width, Lc1, and indent breakwater height, du. The results show that the submerged breakwater performance for a set of U-shape breakwater with the same cross-section area is related to the length of submerged breakwater crest, Lc1, and the distance between the crests, Lc2 (or the height of du). The breakwater has the maximum performance when the crest length is larger, and at the same time, the distance between them increases. Changing the Lc1 and du of the U-shape breakwaters result in a significant change in the RTD coefficients. Comparison of the U-shape breakwater, having the best performance, with the averaged RTD values shows that the transmission coefficients, Kt, has a better performance of up to 4% in comparison to other breakwaters. Also, the reflection coefficients KR and the diffusion coefficients, Kd shows a better performance of about 30% and 55% on average, respectively. However, the model governing equations are non-dissipative. The non-energy conserving of the transmission and reflection coefficients due to wave and breakwater interaction results in dissipation type contribution. The U-shape breakwater with the best performance is compared with the rectangular breakwater with the same cross-section area to investigate the economic advantages of the U-shape breakwater. The transmission coefficients, Kt, of the U-shape breakwater shows a better performance of 5% higher than the rectangular one. The reflection coefficient, KR, is 60% lower for U-shape in comparison to rectangular one; however, the diffusion coefficients, Kd, of U-shape breakwater is 35% higher than the rectangular breakwater. Therefore, we could say that the U-shape breakwater has a better performance than the rectangular one.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.111-117
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• 1983

1979∼1980연 칠월초에 서부 비무장지대 (DMZ)에서 모기 유충채집을 실시한 바 Aedes alboscutellatus의 유충을 제집하여 사육한 결과 성충(♀,♂), 완전유충, 유충 및 편의 탈피각등 분류에 필요한 자료를 얻었다. 이 종은 Reisen등(1971)에 의하여 한국에서 처음 성충(♀)채집을 기록하였으나 이를 확증할 만한 표본이나 분류학적인 기재가 없어 분류상의 오독으로 간주되어 왔었다. 저자등은 본 채집을 통하여 분류상 필요한 모든 자료를 수집하였기에 성충(♀, ♂), 유충, 항, 자충생식기등의 특징을 Reinert(1973)의 기재와 상세히 비교 검토한 결과 웅충에서 gonostylar claw와 basal mesal lobe에 있는 강모의 수가 다르고 자웅충에서는 subspiracular area에 횐 비늘들이 모여있는 점을 발견하였다. 그러나 이들 차이점을 여기에서는 단지 지리적 변화로 간주하였으므로 더 많은 수의 채집을 통하여 보다 확실한 구각이 요구된다 이 표본의 장기보관을 위하여 암수 각 한개섹의 표본과 그에 수반되는 유충 및 편의 탈피곡 표본을 미국 Smithonian연구소에 보냈으며 나머지는 미 8군 예방의무부 곤충연구실에 보관되어 있다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.276-279
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• 2002

A problem formulation and solution for design optimization of laminated composite channel section beam is presented in this study. The objective of this study is the determination of optimum section dimensions of composite laminated channel section beam which has equivalent flexural rigidities to flexural rigidities of steel channel section beam. The analytical model is based on the laminate theory and accounts for the material coupling for arbitrary laminate stacking sequence configuration. The model is used to determine the optimal section dimensions of composite channel section beam. The web height, flange width and thickness of the beam are treated as design variables. The solutions described are found using a global search algorithm, Genetic Algorithms (GA).