• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.466-473
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• 2017

RC (Reinforced Concrete) member has varying service life due to varying diffusion characteristics with loading conditions even if it is exposed to constant exterior conditions. In the paper, quantitative parameters are obtained through adopting the previous results for effects of compressive, tensile, and cold joint on chloride diffusion in OPC (Ordinary Portland Cement) and GGBFS (Ground Granulated Blast Furnace Slag) concrete. Service life is evaluated in RC simple beam with 10.0m of span through increasing loading from self weight (2.5kN/m) to the loading to cracking moment (5.5kN/m). In OPC concrete without cold joint, service life changes to 89.4% for tensile region and 101% for compressive region with loadings while GGBFS concrete has 80.0% and 106%, respectively. For cold joint area, GGBFS concrete shows much reduced service life to 82~80% in compressive region and 69~61% in tensile region, which is caused by the lower diffusion in normal condition but relatively higher increasing cold joint effect than OPC concrete.

• Korean journal of applied entomology
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• v.46 no.3
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• pp.343-348
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• 2007

To assess the environmental risks of transgenic chili pepper with PepEST gene on non-target organisms before it exposes to the agro-ecosystem environments, we conducted the three sets of green peach aphids (Myzus persicas S.) life table experiment under laboratory conditions (Temp. $25^{\circ}C$, R.H. 50-70%, Photoperiod L16 : D8) in series during 2005-2006. We measured the net reproductive rate ($R_0)^*$, the intrinsic rate of increase ($r_m$), the mean generation time ($T_c$), $fecundity^*$, life span, and reproduction period between non-transgenic chili peppers and transgenic chili peppers, respectively. The life span of green peach aphids from three sets was 31, 27, 25 days, and the period of life span was similar to the general average length of green peach aphids, 25-29 days. Although the first reproduction of transgenic pepper was similar to the non transgenic pepper (P>0.05), the fecundity and the net reproductive rate ($R_o$) by using Jackknife method of transgenic pepper were lower than those of non transgenic pepper (P<0.05). Conclusively, we observed the adverse effect from our results but we should execute further experiments to confirm the results at the fields with the similar way.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.63-67
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• 2016

This study examined the biological characteristics of Meganoton scribae under the following conditions: temperature (20, 25, $30^{\circ}C$), humidity ($60{\pm}10%$), and photoperiod (14L:10D). At $25^{\circ}C$, the larval stage of M. scribae lasted for 28.4 d, and the pupal stage for 15.6 d. The average head width was 0.96 mm in the $1^{st}$, 1.34 mm in the $2^{nd}$, 2.07 mm in the $3^{rd}$, 3.64 mm in the $4^{th}$, and 5.89 mm in the $5^{th}$ instar. The life span of female adults was 10.3 d, and the maximum number of eggs spawned was 257.7. The results of the study will be useful for the commercial development of M. scribae.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.788-789
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• 2011

A comprehensive thermo-electromagnetic model has been developed to estimate temperature and electromagnetic distribution in an three-phase induction motor under steady state operation. Electromagnetic modeling enables us to predict thermal dissipation rates by eddy-current loss and copper loss in induction motors. Non-uniform temperature distributions are investigated to account for the strong effect of local temperature build-up on the motor performance and expected life-span. For more accurate thermal modeling purpose, Heat loss mapping method, which is matched up with electromagnetic losses and volumetric heat source, is developed and performed analysis. Heat loss mapping method can be greatly used as a design or diagnostic tool for three-phase induction motors with complex structural electromagnetic fields.

• Computers and Concrete
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• v.19 no.3
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• pp.305-313
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• 2017

A robust finite element based reinforced concrete bridge deck corrosion initiation model is applied for time-dependent probabilistic sensitivity analysis. The model is focused on uncertainties in the governing parameters that include variation of high performance concrete (HPC) diffusion coefficients, concrete cover depth, surface chloride concentration, holidays in reinforcements, coatings and critical chloride threshold level in several steel reinforcements. The corrosion initiation risk is expressed in the form of probability over intended life span of the bridge deck. Conducted study shows the time-dependent sensitivity analysis to evaluate the significance of governing parameters on chloride ingress rate, various steel reinforcement protection and the corrosion initiation likelihood. Results from this probabilistic analysis provide better insight into the effect of input parameters variation on the estimate of the corrosion initiation risk for the design of concrete structures in harsh chloride environments.

• Korean Journal of Poultry Science
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• v.25 no.2
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• pp.65-70
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• 1998

A 16-wk feeding trial was conducted to investigate the proper feeding regimen on the performance of Korean Native Chicken(KNC) consuming broiler diets. Commercial KNC are normally fed 3 kinds of diets during their life span, i. e., starter(S, 0 to 3wk of age), grower(G, 4 to 7wk of age), and finisher(F, 8 to l6wk of age) diets. In this trial, four feeding regimen were employed:T1(S-G-F), T2(S-G-G), T3(S-S-F), and T4(S-F-F). Day-old 360 KNC were randomly allotted to 12 pens: three pens per treatment, and 30 birds per pen. At the end of the trial, the BW of T2 was significantly better than that of T3(P<0.05), and T1 and T4 were intermediate. No significant difference were found in feed intake, feed conversion ratio, and viability among treatments. It appears that, in terms of BW gain, the T2 is the recommendable feeding regimen for KNC consuming broiler diets.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.26-33
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• 2010

A multi-MW wind turbine is a huge mechanical structure, of which the rotor diameter is more or less than 100 m. Rotor blades experience unsymmetric mechanical loads caused by the interaction of incoming wind with the tower and wind shear effect. These mechanical loads are transferred to the entire structure of the wind turbine and are known as the major reasons for shortening the life span of the wind turbine. Therefore, as the size of wind turbine gets bigger, the mitigation of mechanical loads becomes more important issue in wind turbine control system design. In this paper, a concept of an individual pitch control(IPC), which minimizes the mechanical loads of rotor blades, is introduced, and simulation results using IPC are discussed.

• Design & Manufacturing
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• v.2 no.4
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• pp.11-15
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• 2008

In the sheet metal forming using a high speed press machine, driving device, such as crank, link, and knuckle mechanism, has to be designed in consideration of impact at a moment when press die contact with material, because the impact affects a dimensional accuracy of products and a life span of press die. In this study, dynamic analysis was performed using numerical simulation in order to verify the impact reduction effect for proposed double knuckle mechanism by estimating rolling and pitching moment of slide.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.479-482
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• 2003

Radiosensitizing and antitumor effects of hot water extract derived from the seed of Benincasae hispida were investigated. The extract showed maximum survival rate of 21% at 0.1 g/kg against L1210 cells implanted in BDF1 mice. Radiosensitivity of human tumor cell line was evaluated through sulforhodamine assay. Inhibition rate of SK-OV-3 cells after 5 Gy radiation by Benincasae hispida seed extract at 2 mg/mL was 86%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.125-128
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• 2007

The problem of water leakage due to damaging waterproof in concrete structure, causes the impediment in a long term and shortened the life span of durability. There are a lot of techniques for repair and reinforcement to improve using environment. However, the improper construction which is unconsidered various environmental conditions, could effect to increase the maintenance expenses. Therefore, this study will be compared and estimated the adhesion liquid and sheet integrate waterproofing material, as analyzing the existing problem. For those result, we would like to arrange the alterative plan for the long durability and user needs of concrete structure.