• Journal of Korean Association for Spatial Structures
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• v.22 no.3
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• pp.25-32
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• 2022

In this paper, the instability of the domed spatial truss structure using wood and the characteristics of the buckling critical load were studied. Hexagonal space truss was adopted as the model to be analyzed, and two boundary conditions were considered. In the first case, the deformation of the inclined member is only considered, and in the second case, the deformation of the horizontal member is also considered. The materials of the model adopted in this paper are steel and timbers, and the considered timbers are spruce, pine, and larch. Here, the inelastic properties of the material are not considered. The instability of the target structure was observed through non-linear incremental analysis, and the buckling critical load was calculated through the singularities and eigenvalues of the tangential stiffness matrix at each incremental step. From the analysis results, in the example of the boundary condition considering only the inclined member, the critical buckling load was lower when using timber than when using steel, and the critical buckling load was determined according to the modulus of elasticity of timber. In the case of boundary conditions considering the effect of the horizontal member, using a mixture of steel and timber case had a lower buckling critical load than the steel case. But, the result showed that it was more effective in structural stability than only timber was used.

• Journal of the Korean Society of Visualization
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• v.5 no.1
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• pp.9-11
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• 2007

We introduce an in vivo imaging flow cytometer, which provides fluorescence images simultaneously with quantitative information on the cell population of interest in a live animal. As fluorescent cells pass through the slit of light focused across a blood vessel, the excited fluorescence is confocally detected. This cell signal triggers a strobe beam and a high sensitivity CCD camera that captures a snap-shot image of the cell as it moves down-stream from the slit. We demonstrate that the majority of signal peaks detected in the in vivo flow cytometer arise from individual cells. The instrument's capability to image circulating T cells and measure their speed in the blood vessel in real time in vivo is demonstrated. The cell signal irradiance variation, clustering percentage, and potential applications in biology and medicine are discussed.

• Journal of the Korean Graphic Arts Communication Society
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• v.27 no.1
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• pp.15-27
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• 2009

Since domestic offset print quality control depends on the experience of persons in charge rather than objective data, the standards from the data are needed for the well-organized quality management of high-quality prints. Based on the ISO standards, now the standard specifications, such as GRACoL 7, SWOP 11, SNAP, G7 in America, and EURO Color, ECI, BVDM in Europe, and Japan Color 2001, Japan Color 2004 in Japan, are employed. There exists KS for domestic standards. However, since it has been directly imported from ISO Standards, there are discrepancies in printing materials and media. Although the quality management of commercial prints has been focused and studied. For this circumstance, standards are needed for the production of prints to meet international standards. This paper aims to find out suitable ways to approach domestic printing standards using densitometric method and colorimetric method. Printing experiments on this study were performed with domestic process color inks(Cyan, Magenta, Yellow, Black) and domestic coated papers, under the same conditions as the actual commercial printing processes. In densitometric method, how to set up the optimal solid print density was studied through three tests such as the ways to match solid print density and print contrast to GRACoL standards respectively, and the way to get the highest contrast. In colorimetric method, how to get solid print density with the minimum color difference between the $CIEL^*a^*b^*$ color specification values in GRACoL standards and the measured color specification values in prints, was studied.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.111-118
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• 2011

Single-layer latticed domes with rigid-joint have an advantage in the construction cost and the aesthetic. But, in single-layer latticed domes, the joints are hard to discriminate between pin-joint and rigid-joint, and consisted of semi-rigid joint in practical. And the erection of large roof structures requires special techniques. As one of these special techniques is the Step-Up erection method. This paper verified buckling characteristics of single-Layer lamella domes according to the Joint flexibility under construction by Step-up method. The results are follows: As erection steps increase, the buckling strength decreases. It is occurred the joint buckling by snap through on the top of dome when the joint flexibility close the rigid. And large tensile stress distribution appeared in circumferential member of bottom boundary when the step of construction is low. As the step of construction increase, large compressive stress distribution showed in the top of dome.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.7-15
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• 2008

Currently existing high-accuracy and high-speed die sets used in reciprocal press create scratches at the surface of guide posts, steel balls, and bushes due to vertical movement of balls with point-contacts between inner surface of bushes and guide posts. Consequently, accuracy of the die set and the life span of the metal mold are reduced. However, those scratches could reduce the pre-load of the steel ball. This research designed and developed a groove-type die set which improves life span of the die set by eliminating point-contacts of steel balls with guide posts. The guide post consisted of a steel-ball retainer, a steel-ball retainer stopper, a guide bush, a guide pin, a snap ring, and a spring. The steel-ball retainer has 72 holes with 8 columns of 9 holes in each column. The inner surface of the guide bush was grinded(surface roughness: $Ra\;\\;0.2{\mu}m$, accuracy: $0\;{\sim}\;-0.002mm$) after NC turning and heat treatment. Also, a line of small intermediate pocket was processed inside of the guide bush for lubrication and elimination of foreign materials. Guide grooves of steel balls were processed using a wire EDM(Electrical Discharge Machining) after heat treatment. With such a design of the guide post stated above, loads against steel balls could be dispersed greatly by the line contacts through the guide groove between the guide post and the guide bush, and the life span of the guide post could be expanded semi-permanently.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.75-82
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• 2004

Many researcher's efforts have made a significant advancement of space frame structure with various portion, and it becomes the most outsanding one of space structures. However, with the characteristics of thin and long term of spacing, the unstable behavior of space structure is shown by initial imperfection, erection procedure or joint, especially space frame structure represents more. This kind of unstable problem could not be set up clearly and there is a huge difference between theory and experiment. Moreover, the discrete structure such as space frame has more complex solution, this it is not easy to derive the formulation of design about space structure. In this space frame structure, the character of rise-span ratio or load mode is represented by the instability of space frame structure with initial imperfection, and snap-through or bifurcation might be the main phenomenon. Therefore, in this study, space frame structure which has a lot of aesthetic effect and profitable for large space covering single layer is dealt. And because that the unstable behavior due to variation of inner force resistance in the elastic range is very important collapse mechanism, I would like to investigate unstable character as a nonlinear behavior with a geometric nonlinear. In order to study the instability. I derive tangent stiffness matrix using finite element method and with displacement incremental method perform nonlinear analysis of unit space structure, star dome and 3-ring star dome considering rise-span $ratio(\mu}$ and load $ratio(R_L)$ for analyzing unstable phenomenon.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.244-247
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• 2006

Neuronal cell death significantly contributes to neuronal loss in neurological injury and disease. Typically, neuronal loss or destruction upon exposure to neurotoxins, oxidative stress, or DNA damage causes neurodegenerative diseases such as Alzheimer's disease. In this study, we attempted to determine whether ginsenoside Rg3 from red ginseng has a neuroprotective effect via an anti-apoptotic role induced by S-nitroso-N-acetylpenicillamine (SNAP) at the molecular level. We also investigated the antioxidant effect of Rg3 using a metal-catalyzed reaction with $Cu^{2+}/H_2O_2$. Our results showed that Rg3 ($40-100\;{\mu}g/mL$) protected SK-N-MC neuroblastoma cells under cytotoxic conditions and effectively protected DNA from fragmentation. In the signal pathway, caspase-3, and poly (ADP-ribose) polymerase (PARP) were kept at an inactivated status when pretreated with Rg3 in all ranges. In particular, the important upstream p-Akt signal pathway was increased in a dose-dependent manner, which indicates that Rg3 may contribute to cell survival. We also found that oxidative stress can be mitigated by Rg3. Therefore, we have concluded that Rg3 plays a certain role in neurodegenerative pathogenesis via an anti apoptotic, antioxidative effect.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.89-93
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• 2002

One of the primary factors like plate structure in ship is redundancy structure that is comparable with ocean structure and frame structure. The more component material becomes buckling collapsed locally the less structure stiffness becomes accordingly. As a result, by increasing the load distribution of my other subsidiary structure continually component member collapses, therefore the structure could be in danger of collapse. So, in order to interpret this phenomenon precisely, the study on boundary condition of the ship's plate and post-buckling analysis must be considered In this study, the rectangular plate is compressed by the in-plane load Buckling & Ultimate strength characteristics are applied o be the elasto-plasticity large deformation by ansys code with F.E.M method On this basis, elasto-plasticity of the plain plate are investigated. This study proved elasto-plasticity behaviour of the ship's plate in accordance with boundary condition based on the series analysis in case of the compressive load operation

• Journal of Fashion Business
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• v.16 no.1
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• pp.103-120
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• 2012

The study aimed to evaluate the appearance of the men's work clothes jumpers developed to suggest the prototype work clothes jumper patterns by using the 3-D clothing simulation technology. The 3-D simulated clothing images considered the upper body features of men in the age range between 20 and 59 in South Korea. A questionnaire survey conducted previously suggested a basic jumper style with shirt collar and snap opening cuffs for the heavy industry workers; and discomforting parts of the work clothes jumper of the subject workers have been referred to for the experimental jumper appearance test. Besides, defining the measurements of men's upper bodies enabled to generate the men's 3-D virtual models representing each age group's average body feature. The significant body measurement factors for men's 3-D body modeling and jumper pattern-making were stature for the height factor; chest, waist and hip circumferences for the circumference factor; waist back, hip and arm lengths and interscye front/back for the length factor; and back neck breadth for the breadth factor and armscye and scye depths for the depth factor. The men's body measurements of 30's were implemented to three experimental jumper pattern-making methods, i.e. the 1st method using the relations based on stature and chest circumference; the 2nd method using the direct body measurements; and the 3rd method adopting the maximum ease amount of given body measurements whether relations or direct measurements except the direct measurement of scye depth. A comparison among the three experimental jumpers' simulated images highlighted that the appropriate ease amount of the jumper gained higher scores in terms of the jumpers' front, side, back and sleeve parts and the total silhouettes. Therefore the 3rd experimental jumper was finally selected for the heavy industry workers.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.179-183
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• 2005

The High-tensile steel has been recognized as a promising concept for structural design of light weight transportation systems such as aircraft high speed trains and fast ships. Using the high-tensile steel has been widely used in ship structures, and this enables to reduce the plate thickness. Using the high-tensile steel effectively for a ship hull, the plate thickness becomes thin so that plate buckling may take place. Therefore, precise assessment of the behavior of plate above primary buckling load is important. In this study, examined closely secondary buckling behavior after initial buckling of thin plate structure which operated compressive load according to the various kinds of yield stress with simply supported boundary condition. Analysis method is F.E.M by commercial program(ANSYS V7.1) and complicated nonlinear behaviour can analyze using art-length method about secondary buckling.