• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.193-199
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• 2015

Sloshing of LNG cargo can cause high impact loads on the supporting and containing structures. This is particularly critical for membrane-type tanks since these will have flat surfaces and corner regions which can lead to increased peak pressures for sloshing impacts. The membrane-type containment system is much more flexible compared to the steel hull structure. As a result, fluid-structure interaction plays an important role in the structural analysis of the containment system under sloshing load. This study is based on the direct calculation method of applying sloshing loads to the KC-1 basic insulation system using finite element analysis. The structural analysis of KC-1 basic insulation system considers the dashpot as fluid-structure interaction between liquid cargo and the LNG containment system. The maximum stress of the polyurethane form for KC-1 insulation system is 1.5 times lower than one without dashpot.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.144-152
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• 2011

The existing underground trenchless methods use reinforcing rod in steel tube to obtain structural stiffness. However, there are some problems such as inconvenience of work and expensive material fee which are resulted from limited working space and reinforcing work. To resolve these problems, a new trenchless method, namely P.S.T method (Prestressed Segment Tunnel Method), is developed which uses joint to connect the steel segment and form erection structure in underground construction. Further, installing strands for prestressing. In order to evaluate the flexural capacity of the P.S.T method structure, experiment was conducted. The parameters considered in the experiment are the span-to-depth ratio, diameter of steel tube at corner, prestressing force and welding of joint. Altogether examining the flexural behavior, the effect of deflection in structure according to different parameters has also been analysised.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.48-52
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• 1998

The new Nd3Ba5Co4O15 phase was synthesized with Nd2O3, BaCO3, and Co3O4 by solid state reaction at 1200℃ with intermittent grinding. The crystal structure of Nd3Ba5Co4O15 has been refined on X-ray diffraction powder data by means of Rietveld method. The starting model was based on the Nd3.43Ba4.42Co2.23Al1.77O15 structure. The crystal system was hexagonal, space group P63mc(186), a=11.629(3) Å, c=6.842(2) Å. Final R values were Rwp=0.097 and Rp=0.068. The structure consists of clusters of CoVICoIV3O15 in which a CoVI octahedron shares corners with 3CoIV tetrahedra.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.339-345
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• 2012

RMembrane LNG storage tanks have been recently investigated to replace full-containment LNG storage tanks because of safety and cost aspects. Quantitative Risk Analysis (QRA) and Finite Element Method (FEM) were used to evaluate safety of membrane LNG storage tanks. In this study, structural safety evaluation results via FEM analysis showed that both membrane type and full-containment type cryogenic LNG storage tanks with 140,000 $m^3$ capacity were equivalently safe in terms of strength safety and leakage safety of a storage tank system. Also, Fault Tree Analysis (FTA) was used to improve the safety of membrane LNG storage tanks and membrane LNG tanks were modified by adding three safety equipments: impact absorber structure for the low part of the membrane, the secondary barrier to diminish the thermal stress of the corner part of the outer tank, and a pump catcher in case of falling of a pump. Consequently, the safety of the modified membrane LNG storage tanks were proved to be equivalent to that of full-containment LNG storage tanks.

• Journal of the Korean housing association
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• v.25 no.6
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• pp.133-146
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• 2014

This study aims to analyze the changes of adjacent residential area after the restoration of covered urban streams in seoul. The changes of adjacent residential area after restoration were analyzed by changes of land using, urban structure, individual lot of land and architecture to investigate relationship of the urban stream and residential change. The result as follows: the first one is the change of land use and urban structure in adjacent residential area. This change of infrastructure through stream restoration has transformed land use and urban structure in adjacent residential area. Secondly, there is the changes of the individual lot of land. It seemed that new development by combined lots would be concentrated in stream-side blocks. But, the changes of lots such as combining or dividing lots tend to be concentrated in stream-side, main road and main streets. In stream-side, commercial function of land use has changed to residential one which has restored streams landscape by transformation of lots use without changes of ownership-lots. Finally, there is the change of architecture. It turned out new building in adjacent residential area is similar to general development. However, new building in streamside is related to direction of stream. In addition, remodeling and expansion tend to change in commercial buildings on stream-side bridges of corner lots intensively. As a result, it is related to expectation of architectural activation and improvement of sidewalk environment by stream restoration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.665-672
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• 2013

One of the major causes of stiffness and strength degradations in laminated composite structures is the delamination between composite layers. In most engineering applications, laminated composite structures have certain curvatures. If the curved composite structure is subjected to bending that tends to flatten the composite structures, through the thickness stresses can be generated in the thickness direction of the composites. Under normal operation open mode delamination could occur at the sites of peak interlaminar stress. This paper describes a technique to determine radial direction stress of a laminated composite structure using a curved beam. Stacking sequence effects of interlaminar stress were studied. The radial location and intensity of the open mode delamination stress were calculated and compared with the results obtained from the analytical solution and finite element method.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.94-101
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• 2015

When a severe disaster such as a building collapse occurs, a first priority for rapid rescue is to find a location where people are highly expected to be buried but alive. It is, however, very difficult to correctly designate the location of such cavities by conventional geophysical survey due to a pile of debris of building members. In this study, location of possible lifeguard cavities were evaluated through a series of simulations of building collapse by explosion depending on the height of the building, a structure of basement floor and a location of explosion. Three types of building structure: five-story, ten-story and fifteen-story were prepared as a model for the simulation. As a results, in the case of low building, only basement floor partially collapsed. On the other hand, in the case of high building, a collapsed range on the inside of the building increased and lifeguard spaces were formed only in the lateral side or corner of the building. In addition, when a wall exists in the basement floor, the possibility that cavities could be formed increased compared to the cases without wall. However, for the fifteen-story building case, no possible lifeguard cavity was found. It is noted that for a high rise building, the height of building more affect forming of safeguard cavity than the structure of the basement floor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.729-734
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• 2000

Recently, Very Large Scale Integrated (VLSI) circuit & deep-submicron bulk Complementary Metal Oxide Semiconductor(CMOS) devices require gate electrode materials such as metal-silicide, Titanium-silicide for gate oxides. Many previous authors have researched the improvement sub-micron gate oxide quality. However, few have reported on the electrical quality and reliability on the ultra thin gate oxide. In this paper, at first, I recommand a novel shallow trench isolation structure to suppress the corner metal-oxide semiconductor field-effect transistor(MOSFET) inherent to shallow trench isolation for sub 0.1${\mu}{\textrm}{m}$ gate oxide. Different from using normal LOCOS technology deep-submicron CMOS devices using novel Shallow Trench Isolation(STI) technology have a unique"inverse narrow-channel effects"-when the channel width of the devices is scaled down, their threshold voltage is shrunk instead of increased as for the contribution of the channel edge current to the total channel current as the channel width is reduced. Secondly, Titanium silicide process clarified that fluorine contamination caused by the gate sidewall etching inhibits the silicidation reaction and accelerates agglomeration. To overcome these problems, a novel Two-step Deposited silicide(TDS) process has been developed. The key point of this process is the deposition and subsequent removal of titanium before silicidation. Based on the research, It is found that novel STI structure by the SEM, in addition to thermally stable silicide process was achieved. We also obtained the decrease threshold voltage value of the channel edge. resulting in the better improvement of the narrow channel effect. low sheet resistance and stress, and high threshold voltage. Besides, sheet resistance and stress value, rms(root mean square) by AFM were observed. On the electrical characteristics, low leakage current and trap density at the Si/SiO$_2$were confirmed by the high threshold voltage sub 0.1${\mu}{\textrm}{m}$ gate oxide.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.162-177
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• 2003

It has been known that the color of skin reflects the blood flow within. In lips, the capillaries close to the skin surface are numerous; hence lips are redder than the rest of face. However, dermatological research on lips is not as advanced as research on facial or body skin, and little was known about the relationship between relatively dull-colored lips and skin blood flow. The physiological differences between colorful and dull-colored lips were studied by a two-dimensional laser Doppler blood flow analyzer, a spectrometer for the measurement of the degree of oxygen saturation, and a confocal microscope for observing inside lips non-invasively. Dull-colored lips and the corner of lips (dull-colored compared to the center) showed relatively poor blood flow and lower oxygenated hemoglobin. It was found that colorful lips (generally the young) had a blood flow that tended to run straight in parallel with the skin surface. This unique blood-capillary structure can express clear red blood. Those with dull-colored lips had lost this unique structure. Their blood ran perpendicularly from the deep of the skin and down back again into the deep part as like the blood circulation patterns of facial skin. Therefore, the lips of the latter group had fewer blood capillaries near skin surface in the lips than that of the colorful-lips group. A lipstick containing a-glucosyl-hesperidin, which is derived from certain citrus fruits and can enhance blood circulation, was applied for evaluating its effects. Blood flow was increased 30 min after the application. After two weeks of daily application, the lips' condition became noticeably less dull. These findings suggest that the decrease of blood flow in dull-colored lips is caused by the loss of the unique capillary structure and the use of the lipstick to increase blood flow can give a vivid color to lips.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.269-280
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• 2017

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.