• International Journal of Safety
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• v.7 no.1
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• pp.35-38
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• 2008

The purpose of this study is to extract typical body shape of Korean VDT workers based on the three-dimensional Korean shape data and recommendation supported by Korea Occupational Safety & Health Agency during VDT task. Desirable desk heights and chair heights for the selection of the VDT working posture is proposed by analyzing moment, compression and joint shear for lumbar and spine of Korean adult(male and female). The desirable heights for desk and chair can be selected by the least load method during VDT tasks. In the current work the figures of Korean 50th percentile offered by CATIA-HUMAN are used as the average body type of the grown-ups and this research is accomplished with the recommended size of all working attitude such as the height of a monitor except for the height of desk and chair and the degree of watching the monitor.

• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.297-304
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• 2010

The present work focuses on preparation of olanzapine, orally dispersing tablets by direct compression method. Effect of super disintegrant crospovidone, disintegration time, drug content on in vitro release has been studied. A factorial design was employed in formulating a prompt dispersible tablet. The selected independent variables crospovidone and fmelt showed significant effect on dependent variables i.e. disintegration time and percent drug dissolved. Disintegration time and percent drug dissolved decreased with increase in the level of crospovidone. The similarity factor $f_2$ was found to be 97.48 for the developed formulation indicating the release was similar to that of the marketed formulation. Pharmacokinetics of olanzapine after single-dose oral administration of orally disintegrating tablet in normal volunteers were evaluated and the results showed that PK parameters (Cmax, Tmax, AUC) of the designed ODT matrix were similar to those of commercial product, Zyprexa Zydis$^{(R)}$ as a reference.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.855-856
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• 2006

In the present work, hot workability of particulate-reinforced Al6061-20%SiC composite produced by direct hot extrusion technique was studied. Uniaxial hot compression test at various temperatures and strain rates was used and the workability behavior was evaluated from the flow curves and the attendant microstructures. It was shown that the presence of SiC particles in the soft Al6061 matrix deteriorates the hot workability. Bulging of the specimens and flow lines were observed, which indicate the plastic instability during hot working. Microstructure of the composites after hot deformation was found to be heterogeneous, i.e. the reinforcement clusters were observed at the flow lines. The mechanism of deformation was found to be controlled primarily by dynamic recrystallization.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.95-101
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• 2001

This work is concerned with construction of the intelligence stress predictor far compression strength evaluation using neural network-ultrasonic waves. The contact pressure in jointed plates was measured by using ultrasonic technique. Neural network is used to evaluate and predict contact pressure from the results of the calibration curves. The organized neural system was leaned with the accuracy of 99%, as a result of learning the ultrasonic echo ratio to the contact pressure measurement between SM45C and STS410 materials. And it could be evaluated and predicted with the accuracy of 90% in the evaluation of ultrasonic echo ratio difference in the same surface roughness and contact pressure, and 85% in the prediction of virtual ultrasonic echo ratio. Thus the proposed stress predictor is very useful for the evaluation and prediction of the contact pressure between SM45C and STS410 materials.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.2
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• pp.19-27
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• 1984

An extension of the finite element method to the stability analysis of shells of revolution under static axisymmetric loading is presented in this paper. A systematic procedure for the formulation of the problem is based upon the principle of virtual work. This procedure results in an eigenvalue problem. For solution, the shell of revolution is discretized into a series of conical frusta. The buckling mode in the circumferential direction is assumed, this assumption makes the problem economical for the computing time. The present method is applied to a number of shells of revolution, under axial compression or lateral pressure, and comparision are made with other theoretical results. The results show good agreement each other. The effects of aspect ratio, boundary conditions and buckling modes on the buckling strength of shells of revolution are studied. Also the optimum shape of cylindrical shell under uniform axial compression is obtained from the view point of structural stability.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.2
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• pp.181-189
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• 2000

The scroll compressor used for heat pump has a wide range of operation condition. To cover both heating and cooling modes, the operating Pressure ratio ranges from 1.5 to 6.8. Since the scroll compressor, however, is a type of compressor whose pressure ratio is fixed, some loss in the compression work is caused by the operation at the pressure ratio different from the built-in pressure ratio. A way of avoiding this problem is to introduce by-Pass holes in compression chambers, so that the compressed gas of pressure higher than the discharge pressure, yet not reached to the discharge port can be released earlier through the by-Pass holes. In this paper, an optimum Positioning of the by-Pass hole and the effect of the by-pass valve on the compressor performance are studied.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.9
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• pp.367-372
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• 2016

Gas diffusion layer (GDL) of PEMFCs plays a role that it diffuses the reactant gases to the catalyst layer on the membrane and discharge water from the catalyst layer to the channel. Physical parameters related to the mass transport of GDL are mostly from the uncompressed GDLs while actual GDLs in the assembled stacks are compressed. In this study, the relation of compression and strain of GDLs with various Polytetrafluoroethylene (PTFE) loading is measured experimentally and In-plane gas permeability is measured at the condition that the GDLs are in compressive strain. The gas permeability decreased with the loading of PTFE and the presentation of gas permeability under compressive stain is expected to improve the accuracy of modeling work of mass transport in the GDL.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.89-95
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• 1999

The compression behavior of semi-solid materials in studied from a viewpoint of yield criteria and analysis methods. To describe the behavior of materials in semi-solid state, several theories have been proposed by extending the concept of plasticity of porous compressible materials. in the present work, the upper-bound method and the finite element method are used to model the simple compression process using yield criteria of Kuhn and Doraivelu. Segregation between solid and liquid which cause defect of product is analysed for Sn-15%Pb alloy is compared with the experimental result of Charreyron et al..

• Journal of the Korean Society for Heat Treatment
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• v.32 no.1
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• pp.1-11
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• 2019

In this study, microstructure evolution and crystallographic orientation are investigated under various deformation conditions in M1 magnesium alloy. M1 magnesium ingot was rolled at 673 K with the rolling reduction of 30%. The compression test specimens were machined out from rolled plate, and then the specimens were annealed at 823 K for 1h. Uniaxial compression tests were conducted at 723 K and under the strain rate ranging from $5.0{\times}10^{-4}s^{-1}$ to $5.0{\times}10^{-2}s^{-1}$ up to a true strain of -1.0. For observation of crystal orientation distribution, EBSD measurement was performed. Occurrence of the dynamic recrystallization and grain boundary migration were confirmed in all case of the specimens. The distribution of the grains is not uniformed in the experimental conditions.

• Korean Journal of Metals and Materials
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• v.48 no.4
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• pp.305-314
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• 2010

The development of textures and microstructures during plastic deformation in a hot-extruded AZ 31 Mg alloy was investigated using a compression test with such parameters as deformation temperature, strain rate. It was observed from true stress-strain curves that twinning involves changes of the flow stresses. In the early stages of deformation at temperatures lower than $200^{\circ}C$, the occurrence of twins resulted in a decrease of the work-hardening rate, which increased drastically at a true strain of -0.05. The evolution of the deformation textures were assessed with the aid of EBSD analyses in terms of the competition between twinning and slip activity.