• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.342.1-342
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• 2002

In this work, the dynamic characteristics of an oil-lubricated, short SFD with a central feeding groove are derived based on a theoretical analysis considering the effect of a groove. The validity of the analysis is investigated experimentally using an Active Magnetic Bearing (AMB) system as an exciter. For the theoretical solution, the fluid film forces of a grooved SFD are analytically derived so that the dynamic coefficients of a SFD are expressed in terms of its design parameters. (omitted)

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.248-252
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• 1998

To prolong the biological half-life of streptokinase, a thrombolytic agent, streptokinase-bearing liposome with and distearolyphosphatidyl ethanolamine-N-poly (ethylene glycol) 2000 (DSPEPEG 2000) was prepared and evaluated. Streptokinase-bearing liposomes composed of distearolyphosphatidylcholine (DSPC), cholesterol and cholesterol-3-sulfate with DSPE-PEG 2000 was prepared by the freeze-thawing method and administered via femoral vein to rats (15000 IU/kg). The activity of streptokinase in plasma was determined by the method based on the amidolytic activity of streptokinase-plasminogen complex. Pharmacokinetic parameters of streptokinase incorporated in liposomes were compared with those of streptokinase alone. The $T_{1/2}$ and $AUC_\infty$ streptokinase incorporated in DSPC-PEG liposome increased 16.3- and 6.1-fold, respectively, compared with those of streptokinase alone. Streptokinase-bearing long-circulating liposome could increase the circulation time of streptokinase in blood and expect longer thrombolytic activity compared with streptokinase alone.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.615-620
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• 2005

The purpose of this study was to provide a criterion of ballast aggregate size distribution for paved track. The parameters considered in this study were different types of particle size distribution. Then the analysis for analyzing compressive and flexural strength, physical characteristics of aggregate, and the ballast box test were performed. In the test result of the physical characteristic performed by the ballast box test, the bearing capacity was measured lower than the expected value because of its boundary conditions. Among four types of ballast aggregate, type B was selected as one of best candidate distribution because of its bearing capacity, strength, development and economics.

• Tribology and Lubricants
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• v.23 no.5
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• pp.240-247
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• 2007

The design process of the dental handpiece is described. The parameters of the high speed air turbine are estimated. The effect of supply hole on the stiffuess and damping of the air bearing for handpiece is studied numerically. The Reynolds equation is solved by using the divergence formulation and the perturbation method. The test rig is built and the test procedure is developed for the turbine rotational speed measurement by using Fourier transform of noise generated by the turbine during steady operation.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.112-119
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• 2003

This paper presents the identification of rotor dynamic parameters. The solution of the system equation can be obtained using least square method. The sensitivity analysis is performed to extract optimized solution, which is considered to be insensitive to inherent measurement errors. The cosine and sine term of orbit shapes can be obtain ed through the by experiment of the orbit analysis at a different speed after doing orbit analysis at an arbitrary selected speed. This values measured time domain are used to search the stiffness and damping coefficients of rotor bearing.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.116-121
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• 1999

Since the material flow near the die part in CONFORM (Continuous Extrusion Forming) process is similar to that of side-extrusion, the side-extrusion model of tube shaped aluminum profiles was studied for the die design in CONFORM process. In this paper, the effects of process parameters in the side -extrusion through a two-hole die face, such as material flow, height and thickness of the tube, velocities of punch and lengths of bearing land were investigated using UBET program and DEFORM commercial FEM code. The optimum lengths of the bearing lands and punch velocities for obtaining the straight shape products required were determined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.333-338
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• 1997

A hollow crankshaft is considered as part of an effort to reduce the weight of the automobile powertrain. Since the resulting mass reduction alters both the inertia and stiffness properties of the crankshaft, the vibration characteristics of the hollow crankshaft needs to be investigated in comparison with the original solid crankshaft. The crankshafts are modeled by 38 lumped mass and stiffness elements, in which the dynamic parameters for each lumped element are obtained by the finite element calculation. The fluid-film bearings supporting the crankshaft give rise to linear spring and damping elements that can be derived from the hydrodynamic bearing model. The transfer matrix method is applied to yield the natural frequencies and mode shapes of the crankshaft vibration. The natural frequencies of the hollow crankshaft are founded to be greater than that of the solid crankshaft, and the incorporation of the bearing stiffness tends to accentuate the difference.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.131-137
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• 2000

In order to evaluate the design shear strength of composite slabs with truss-shaped shear connectors(TSC), a series of push-out tests on several types of specimens was carried out. The test results for the two parameters of bearing area and solid angle of the connector were compared to obtain the design shear force of the truss-shaped connectors. The results obtained from this study are as follows: (1) The slip-coefficients of TSC ranges from 0.87 to 3.12(${\times}10^6kgf/cm$). (2) The slip stiffness and the shear strength of TSC with $60.6cm^2$ bearing area are greater than those with $14.6cm^2$. (3) For estimating the allowable shear force of TSC, a design equation that is based on the bearing strength of the connector is suggested. (4) The mean safety factors of the critical force and the ultimate force are 2.38 and 4.62. respectively.

• Structural Engineering and Mechanics
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• v.40 no.2
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• pp.215-231
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• 2011

The axial compressive strength of unidirectional FRP is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. In order to restrain the lateral expansion and splitting of GFRP, and accordingly heighten its axial compressive bearing capacity, a project that to confine GFRP pole with surrounding CFRP sheet is suggested in the present study. The Experiment on the CFRP sheet confined GFRP poles showed that a combined structure of high bearing capacity was attained. Basing on the experiment research a theoretical iterative calculation approach is suggested to predict the ultimate axial compressive stress of the combined structure, and the predicted results agree well with the experimental results. Then the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure are also analyzed basing on this approach.

• Earthquakes and Structures
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• v.10 no.1
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• pp.179-190
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• 2016

A single rigid footing constructed on sandy-clay soil was modeled and analyzed using FLAC software under static conditions and vertical ground motion using three accelerograms. Dynamic analysis was repeated by changing the elastic and plastic parameters of the soil by changing the percentage of cement grouting (2, 4 and 6 %). The load-settlement curves were plotted and their bearing capacities compared under different conditions. Vertical settlement contours and time histories of settlement were plotted and analyzed for treated and untreated soil for the different percentages of cement. The results demonstrate that adding 2, 4 and 6 % of cement under specific conditions increased the dynamic bearing capacity 2.7, 4.2 and 7.0 times, respectively.