• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.342-349
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• 1998

The objective of this study is to investigate the characteristic change of antiwashout underwater concrete with variation of blend ratio of sea sand and fine aggregate percentage through experimental researches. According to the experiments results, when sea sand are mixed in antiwashout underwater concrete mixture by about 40% per total fine aggregate, in fine aggregate percentage of 40%, it is found that the flowability fit and the compressive strength is higher others.

• Journal of Korean Society for Quality Management
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• v.27 no.3
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• pp.67-78
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• 1999

In parameter design introduced by Taguchi, we analyze a performance measure, so called SN ratio. The SN ratio is a function of the expected loss due to the variation of quality characteristic. In this paper, an easy way for developing performance measures is presented, which can be used to control several quality characteristics simultaneously in parameter design. To develop such multivariate performance measures, the transformation method of the expected loss and combining techniques are employed. And the analysis of real empirical data for an application of the proposed method is also presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.250-251
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• 2017

In study, the lightweight insulation mortar is produced with more than 50,000tons of waste each year, but it is difficult to treat with the degradable composite material and the recycling ratio is still 50%. the lightweight insulation mortar is manufactured by using the ratio of expanded polystyrene and pulverized expanded polystyrene.

• YAKHAK HOEJI
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• v.31 no.3
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• pp.182-188
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• 1987

Simple coacervation of bovine serum albumin was studied to prepare biodegradable microacapsule. Albumin microcapsules were prepared by using acrylonitrilestyrene polymer (M-80) resin beads and sulfamethoxydiazine as the core materials. The albumin to beads ratio was found to be 1:2.3 and the albumin to sulfamethoxydiazine ratio to be 1:2.9. The 50% release times (T$_{50%}$) of sulfamethoxydiazine and microencapsulated sulfamethoxydiazine were 6 min. and 73 min., respectively. The surface appearance of the microcapsule collected after release experiment was not different from those of the original microcapsule. In addition to slowing release of drug the microencapsulation process masked characteristic bitter taste of sulfamethoxydiazine.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.321-328
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• 1998

In this study we have studied running stability, safety and passenger comfort of the Chinese first class passenger car made by our company and CCRW. A fine analysis model of 72 d.o.f. was constructed for simulating dynamic behavior of the car on straight and curved tracks having irregularity configurations. We have calculated the various characteristic values such as critical speed, lateral force, derailment ratio, wheel unloading ratio and passenger comfort index, then evaluated them by comparing with reference values.

• Journal of Industrial Technology
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• v.36
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• pp.17-22
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• 2016

A circular pin fin (CPF) and a half circular pin fin (HCPF) are by using the one-dimensional analytic method. For these two fins, 90% of the maximum heat loss, Corresponding fin length for 90% of the maximum heat loss, fin effectiveness and fin efficiency are compared as functions of convection characteristic number and fin radius. Also, the ratio of heat loss from the HCPF to that from CPF listed with variation of fin length when the fin volumes are the same. One of the results shows that the efficiency of a CPF is larger than that of a HCPF while the effectiveness of a CPF is smaller than that of a HCPF when convection characteristic number, fin length and fin radius are the same.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.932-937
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• 2008

The asphalt waste has been collected more than ten thousands' ton from repairing works on the road and excavation repair works, most of them are disposed on land of reclamation. Only a few percentage of wasted asphalt recycled to new one. Therefore, In this study, usage of wasted asphalt and has been done engineered characteristic test for recycling materials of sub-grade and structure. To know the characteristic of asphalt waste, tamping test, bearing-ratio test, permeability test and direct shear test was done using asphalt-sand mixture. The test results shows that, mixed asphalt materials with sand can be used for materials of subgrade-soil and structure.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.35-44
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• 2006

Operation conditions of a reheat cycle gas turbine for a combined cycle power plant was analyzed. Based on measured performance parameters of the gas turbine, a performance analysis program predicted component characteristic parameters such as compressor air flow, compressor efficiency, efficiencies of both the high and low pressure turbines, and coolant flows. The predicted air flow and its variation with the inlet guide vane setting were sufficiently accurate. The compressor running characteristic in terms of the relations between air flow, pressure ratio and efficiency was presented. The variations of the efficiencies of both the high and low pressure turbines were also presented. Almost constant flow functions of both turbines were predicted. The current methodology and obtained data can be utilized for performance diagnosis.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1821-1832
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• 2005

This study realizes the conceptual method to predict combustion instability in actual full-scale combustion chamber of rocket engines by experimental tests with model (sub-scale) chamber. The model chamber was designed based on the methodologies proposed in the previous work regarding geometrical dimensions and operating conditions, and hot-fire test procedures were followed to obtain stability boundaries. From the experimental tests, two instability regions are presented by the parameters of combustion-chamber pressure and mixture (oxidizer/fuel) ratio, which are customary for combustor designers. It is found that instability characteristics in the chamber with the adopted jet injectors can be explained by the correlation between the characteristic burning or mixing time and the characteristic acoustic time: In each instability region, dynamic behaviors of flames are investigated to verify the hydrodynamically-derived characteristic lengths of the jet injectors. Large-amplitude pressure oscillation observed in upper instability region is found to be generated by lifted-off flames.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.775-780
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array Is made. Therefore this study carried to decide design variables for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design variables.