• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.229-230
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• 2010

By using the experiment, it can analyze strain properties of that when the concrete using light and nomal-weight aggregate takes a various under-loading level at elevated temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.281-282
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• 2010

In this study, it aimed to analyze relation of stress and strain strain for concrete with various under-loading level at elevated temperature.

• Journal of Biomedical Engineering Research
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• v.36 no.6
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• pp.276-282
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• 2015

Recently, during the multi-level fusion with pedicle screws, interspinous spacer are sometimes substituted for the most superior level of the fusion in an attempt to reduce the number of fusion level and likelihood of degeneration process at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the interspinous spacer combined with posterior lumbar fusion with a previously-validated 3-dimensional FE model of the intact lumbar spine (L1-S1). The post-operative models were made by modifying the intact model to simulate the implantation of interspinous spacer and pedicle screws at the L3-4 and L4-5. Four different configurations of the post-op model were considered: (1) a normal spinal model; (2) Type 1, one-level fusion using posterior pedicle screws at the L4-5; (3) Type 2, two-level (L3-5) fusion; (4) Type 3, Type 1 plus Coflex$^{TM}$ at the L3-4. hybrid protocol (intact: 10 Nm) with a compressive follower load of 400N were used to flex, extend, axially rotate and laterally bend the FE model. As compared to the intact model, Type 2 showed the greatest increase in Range of motion (ROM) at the adjacent level (L2-3), followed Type 3, and Type 1 depending on the loading type. At L3-4, ROM of Type 2 was reduced by 34~56% regardless of loading mode, as compared to decrease of 55% in Type 3 only in extension. In case of normal bone strength model (Type 3_Normal), PVMS at the process and the pedicle remained less than 20% of their yield strengths regardless of loading, except in extension (about 35%). However, for the osteoporotic model (Type 3_Osteoporotic), it reached up to 56% in extension indicating increased susceptibility to fracture. This study suggested that substitution of the superior level fusion with the interspinous spacer in multi-level fusion may be able to offer similar biomechanical outcome and stability while reducing likelihood of adjacent level degeneration.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.131-137
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• 1998

A composite copper coated powder was generated by pressure hydrogen stripping copper from Kelex 100 solvent extractant in the presence of silica powder. Within the limitation of solvent extraction under constant conditions, both loading level and stripping rate were reproducible. The stripping copper kinetics are reduced from a divalent state to a metallic state and then deposited on the surface of the silica powder. Copper nucleates heterogeneously on the seed particles. They are giving an agglomerated and non - uniform powder.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.211-214
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• 2005

This research studied robust design of composite structure under combined loading of bending and torsion. DOE (Design of Experiment) technique was used to find important design factors. The results show that the beam height, beam width, layer thickness and stack angle of outer-layer are important design parameter. The $2^{nd}$ DOE and RSM (Response Surface Model) were conducted to obtain optimum design. Multi-island genetic algorithm was used to optimum design. An approximate value of 6.65 mm in deflection was expected under optimum condition. Six sigma robust design was conducted to find out guideline for control range of design parameter. To acquire six sigma level reliability, the sigma level reliability, the standard deviation of design parameter should be controlled within 2.5 % of average design value.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.529-535
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• 2001

A centrifugal fan design code was developed and packaged together with iDesignFan／sup TM／ as new models. This code generate centrifugal forward curved and backward curved bladed impeller optimally. It also predicts the aerodynamic performance and the overall sound pressure level of the rotating fan by assuming steady blade loading. The overall sound pressure level is used as an input parameter from the third loop of the designing process to acquire the most silent fan for the given aerodynamic performance parameters. With this kind of inverse design concept used in the code, the period of designing a fan is significantly shortened. A centrifugal fan design code, developed in this study and included in iDesignFan／sup TM／, predicts the aerodynamic performance such as design flow rate and static pressure. The aerodynamic performance in the design and off-design conditions is calculated by using the mean line analysis. For the steady loading calculation, the lift force distribution in a blade is used.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.229-234
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• 2008

An AC-DC transfer standard(TS) is used for the AC voltage standard in the range of 2 mV to 1000 V below 1 MHz. Micro-potentiometer(${\mu}Pot$) is used to evaluate the ac-dc transfer difference(ADD) of the TS below 200 mV range. The ADD of the TS were changed by the loading effect caused from the input impedance change of the TS depend on frequency. An input impedance evaluation technique of the TS using ${\mu}Pot$ has been developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.903-907
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• 1996

Under two level block loading, the carbornitrizing specimen can be expected to show different behavior from other uniform material because the properties of surface layer and inner material are different from each other. In this research, the modified Marco-Starkey cumulative theory, which considers load interaction effect, can predict the life of SCM415 carbornitrizing and original notched and smooth specimen, In the low-high test of carbornitrizing specimen which has long life, however, we may additionally consider the increase of life by means of the stress hardening of inner original material.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.1
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• pp.106-117
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• 1998

The nature of stress-path dependency, the principle that governs deformations in granular soil, and the use of Lade's double work-hardening model for predicting soil response for a variety of stress-paths have been investigated, and are examined The test results and the analyses presented show that under some conditions granular soils exhibit stress-path dependent behavior. For stress-paths involving unloading or reloading, the stress-path with the higher average stress level produces the larger strains, whereas all stress-paths having the same intial states of stress, and involving only primary loading conditions, produce strains of similar magnitudes. Experimental evidence indicates that the stress- path dependent response obtained from the double work-hardening model is also observed for real soils. It is concluded that the influence of stress history on the friction angle is negligible and the strains increment direction is uniquely determined from the state of stress but is not perpendicular to the yield surface. The strains calculated from Lade's double work-hardening model are in reasonable agreement with those measured.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.391-394
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• 2012

Exposure and risk assessment during mixing/loading of chlorpyrifos emulsifiable concentrate (EC, 20%) were carried out. Limit of detection and limit of quantitation were 0.02 and 0.1 ng, respectively. Calibration curve linearity and reproducibility were excellent. Recovery of chlorpyrifos from gloves was 72.3-103.4%. During mixing/loading procedure, average hand exposure amount of chlorpyrifos was 3.9 mg which is corresponding to 0.004% of total active ingredient in the prepared spray mixture. In calculation of MOS (Margin of Safety) for risk assessment, male Korean average body weight and AOEL (Acceptable Operator Exposure Level) were used. Nine events of mixing/loading procedure were assumed per day. And 75 percentile of 30 repetition (4.6 mg) was used as for the worst case. MOS was more than 1 for total repetition, indicating mixing/loading work was of least risk. However, MOS of individual repetition was examined, two cases were less than 1 suggesting careful work habit is essential in mixing/loading procedure.