• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.375-379
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• 2016

A rat is the most common experimental animal used for the realization of the radiation injury model. The certain thickness of rat skin was prepared by peeling off a rat skin. Radiation level was measured by using this rat skin. Also, The schematic of the formula was made that can predict the radiation absorbed dose (RAD) as a function of the thickness of the rat skin. Consequently, we will provide the RAD information in the realization of in-vitro experimental model regarding the rat's skin thickness by applying the formulas. Moreover, the results from this study can be effectively used for the in-vitro experiment of the rat subcutaneous tissue which was exposed to radiation.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.545-552
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• 2009

An experimental study was performed on the yLRC composite column. Its external surface was manufactured with y-shape steel sheets and L-shape steel angles, and concrete was poured inside in the field. This composite column has improved the section capacity due to the composite action of steel and concrete, and provides good efficiency in reducing the terms of construction works because of its abridged formworks. The stub column specimens (three small and three large specimens) were tested through concentrical axial loading, and the effect of the width-to-thickness ratio of the steel angle on the column axial strength was examined. The axial strength and behavior of the composite columns were analyzed, and a formula for predicting the axial load capacity was proposed.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.179-190
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• 1998

Shear failure of reinforced concrete (RC) beams is serious problem due to sudden brittle failure and many experimental results proved that size effect in shear strength of RC beams is an important feature of reinforced concrete members. As the sizes of RC beams very large, experiments sometimes become very difficult so that empirical design formula or the experimental data on shear strength of RC beams could not be obtained. Then the numerical analyses for size effect on shear strength of RC beams become very important. In this study, finite-element technique of reinforced concrete is employed of shear analysis of RC beams without web reinforcement and the size effects in shear strength are numerically analyzed. The influencing factors to the size effect in the shear strength of RC beams are extensively analyzed and compared with those by major shear strength equations including several standard specifications.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.25-31
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• 2003

This research aimed to experimentally and theoretically investigate the moment strength of deck plates. A moment experiment was carried out using a full-scale 14 specimen. To prevent local buckling, the point load was applied at 1/4 points. After the experiment, theoretical analysis was conducted and the differences between various codes were identified. The experimental results were compared with AISI (the American Iron and Steel Institute), EC (Euro Code) 3, and KS (Korea Standard) codes. Analysis results are summarized as follows: (1) the failure mode was influenced by local buckling at the midpoint of the beam and/or at the intermediate loading point: (2) if yielding first occurred at the tension side, the moment strength would increase as the plastic reservation of the tension zone acted: (3) the experimental results were closest to the EC3 codes in which the partial plastic reservation was considered; (4) statistical evaluation based on the EC3 Annex Z showed that the partial resistance safety coefficient calculated applying to the EC3 formula, $^{\circ}{_M}$, was placed within 1.1 which was the target value of EC3 code; and (5) the analytical power of AISI and KS codeswere expected to improve into the level of EC3 codes if the concept of plastic reservation of the tension side would be introduced to them.

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.735-742
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• 2012

This paper presents the experimental results of axially loaded stub columns of slender steel hollow square section(SHS) strengthened with carbon fiber reinforced polymers(CFRP) sheets. 6 specimens were fabricated and the main parameters were: width-thickness ratio(b/t) and CFRP retrofitting. From the tests, it was observed that two sides would typically buckle outward and the other two sides would buckle inward. A maximum increase of 33% was achieved in axial-load capacity. Also, stiffness and ductility index(DI) were compared between unretrofitted specimens and retrofitted specimens. In the last section, a prediction formula of the ultimate strength developed using the experimental results is presented.

• Steel and Composite Structures
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• v.27 no.5
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• pp.537-543
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• 2018

Mechanical shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface in composite beams. Steel pipe as a new shear connector is proposed in this research and its performance to achieve composite strength is investigated. Experimental monotonic push-out tests were carried out for this connector. Then, a nonlinear finite element model of the push-out specimens is developed and verified against test results. Further, the finite element model is used to investigate the effects of pipe thickness, length and diameter on the shear strength of the connectors. The ultimate strengths of these connectors are reported and their respective failure modes are discussed. This paper comprises of the push-out tests of ten specimens on this shear connector in both the vertical and horizontal positions in different reinforced concretes. The results of experimental tests are given as load-deformation plots. It is concluded that the use of these connectors is very effective and economical in the medium shear demand range of 150-350 KN. The dominant failure modes observed were either failure of concrete block (crushing and splitting) or shear failure of pipe connector. It is shown that the horizontal pipe is not as effective as vertical pipe shear connector and is not recommended for practical use. It is shown that pipe connectors are more effective in transferring shear forces than channel and stud connectors. Moreover, based on the parametric study, a formula is presented to predict the pipe shear connectors' capacity.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.229-240
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• 2004

Many experiments have been performed to investigate eccentric shear strength and unbalanced moment-carrying capacity of flat plate-column connections under combined gravity and lateral load. However, each existing experiment used different test setup, and the shear strength of the connection was different depending on the test setup. Current design methods which were based on the experimental results might not accurately explain the shear strength of the flat plate. In a companion study, based on results of nonlinear finite element analyses, an alternative design method for the plate-column connection was developed. However, in this method, eccentric shear strength of the connection which was required for assessing unbalanced moment-carrying capacity was evaluated by an empirical formula. In the present study, a theoratical approach using Rankine's failure criterion was attemped to investigate failure mechanism of the eccentric shear. Based on the results, an improved strength model of the eccentric shear was developed, and it was verified by comparison with the existing experimental results. By means of the strength model, the design method developed in the companion study was re-verified.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.1
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• pp.67-75
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• 2010

Submarine and deep sea diving structures are generally designed based on their ultimate strength. Fatigue strength at welded joint must be also taken into account because working stress is increased due to the increasing of diving depth and using high yield steel. The pressure hulls of submarine are subjected to fluctuating compressive loading. But in addition to the calculated stresses, high residual tensile stresses at welded part have to be considered. The state of stress level of pressure hull is tensile at surface and compressive at deep diving depth. This paper presents the results of an experimental investigation on the crack initiation and growth at the weld toe of T welded joints of HY-100 steel plate under constant amplitude loading. It is also investigated the phenomenon of the fatigue failure and test methods. Fatigue tests have been using real scaled local structural models of full penetration T-welded joint, which is a part of the cylindrical shell structures reinforced by ring stiffeners. Several load ratios under constant amplitude loading are considered in the tests. Crack initiation and growth characteristics are examined based on the beach marks of the cracked section of the test specimens. A design stress-life curve including the design formula is suggested according to tested data.

• The Journal of Korean Obstetrics and Gynecology
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• v.29 no.2
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• pp.99-112
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• 2016

Objectives: Gyejibokryeong-hwan (GBH), a traditional Korean herbal medicine, has been widely used for the treatment of the blood stasis syndrome. This study is purposed to analyze the experimental research trend of GBH in Korea for developing further research plan. Methods: A search of Korean research database-Oasis, RISS and KISS- and Pubmed was carried out for publications until 2015, for the words, 'Guizhifulingwan', ‘Gyejibokryeonghwan’, or ‘Keishibukuryogan’. Then study selection is conducted according to PRISMA guidelines, studies not related or using modified formula or administered for human are excluded, 48 studies are included in this review, finally. We analyzed studies by research method, subject, outcome measure, and result of the study. Results: There were 31 in vivo studies about the effect of GBH on platelet aggregation, anti-oxidant, blood viscosity, and hypercholesterolemia, etc. 12 in vitro studies were about the effect of GBH on the cervical carcinoma, chronic kidney disease, uterine myoma, hepatocarcinoma, atherosclerosis, cancer chemo-prevent. 9 ex vivo studies were about the effect of GBH on the platelet aggregation, chronic kidney disease, ovaulatory disorder, and rheumarthritis.Conclusions: We proposed the translational research of GBH involving scientific discoveries and developing practical applications by investigating the concept of blood stasis syndrome in terms of current physiopathological mechanism.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.10-20
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• 1992

The new course distances of a ship are considered to be the indices to indicate directly her abilities of course altercation. Generally, they have long been calculated by using the maneuvering indices obtained from her Z test. However, at sea actually the maneuvering indices can not sometimes be obtained according to ship's condition or circumstances and the new course distances can not be calculated. To find out other method to calculate the new course distances, in this paper the author analyzed them from a viewpoint of ship motion, and worked out a numerical formula to calculate them easily, using the data of ship's heading test. In order to check whether the presented method is applicable to actual ships or not, the experiment by them were also performed. The results obtained are summarized as follow: 1. The mean difference of the distance between two new course distances by the heading test and the maneuvering indices of the experimental ship was about 0.98% values of the ones by the maneuvering indices, when her heading were 10。, 20。 and 30。, using the rudder angle of 15。. These new course distances were therefore found to be almost same in values of the distance. 2. The mean difference of the distance between two new course distances by the heading test and the observation of experimental ship was about 1.16% values of the ones by the observation, when her headings were 10。, 20。 and 30。, using the rudder angle of 15。. These new course distances were therefore found to be almost same in values of the distance. 3. It is confirmed that the new course distances can be calculated easily by using the method of ship's simple heading test, without the observation or using the maneuvering indices. 4. It is considered to be helpful for the safety of shiphanding to draw curves of new course distances by ship's heading test and utilize them at sea.