• Corrosion Science and Technology
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• v.9 no.1
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• pp.29-33
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• 2010

Laser machining technique, which is used focusing pulse YAG laser beam irradiation was applied to form area ratio controlled model cut-edge on pre painted Zn coated steels. A corrosion behavior of formed model cut-edge was investigated by rest potential measurement in 1 mol $m^{-3}$ NaCl with and without 0.5 kmol $m^{-3}$ $H_3BO_4$/0.05kmol$m^{-3}$ $Na_2B_4O_7$. The rest potential showed almost constant value with fluctuations. The amplitude of fluctuations increased with exposed area of steel surface. White corrosion products of zinc oxide and simonkollite was formed after the experiments at the formed model cut-edge.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.655-663
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• 2024

In order to meet the technological demand for indoor heating systems that ensure winter thermal comfort during the transition from internal combustion engines to electrification, a localized proximity heating module using surface heating elements was developed. The operational performance of heating module was tested in the low temperature chamber. The experiment conditions were varied by changing the chamber temperature (-10, 0℃), the air flow rate (6.2, 6.0, 4.2m³/h), the heater power (100, 80, 60, 40W). Thermal comfort model was confirmed using the CBE Thermal Comfort Tool applying ASHRAE standard 55. Under -10℃ condition, thermal comfort was satisfied at 23.4, 23.2℃ at power of 100W and air flow rate 6.0, 4.6m³/h. Under 0℃ condition, at power of 80W, air flow rate 6.2, 6.0m³/h, and at power of 60W, air flow rate 4.6m³/h showed results of 25.7, 26.1, 23.0℃, respectively, satisfying thermal comfort. This study analyzed the operating performance of the local proximity heating module in the low temperature chamber and applied thermal comfort model to prove applicability of local proximity heating module using surface heating elements and how to utilize the thermal comfort model.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1495-1502
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• 2014

Metarhizium anisopliae is a widely studied model to understand the virulence factors that participate in pathogenicity. Proteases such as subtilisin-like enzymes (Pr1) and trypsin-like enzymes (Pr2) are considered important factors for insect cuticle degradation. In four M. anisopliae strains (798, 6342, 6345, and 6347), the presence of pr1 and pr2 genes, as well as the enzymatic activity of these genes, was correlated with their virulence against two different insect pests. The 11 pr1 genes (A, B, C, D, E, F, G, H, I, J, and K) and pr2 gene were found in all strains. The activity of individual Pr1 and Pr2 proteases exhibited variation in time (24, 48, 72, and 96 h) and in the presence or absence of chitin as the inductor. The highest Pr1 enzymatic activity was shown by strain 798 at 48 h with chitin. The highest Pr2 enzymatic activity was exhibited by the 6342 and 6347 strains, both grown with chitin at 24 and 48 h, respectively. Highest mortality on S. exigua was caused by strain 6342 at 48 h, and strains 6342, 6345, and 6347 caused the highest mortality 7 days later. Mortality on Prosapia reached 30% without variation. The presence of subtilisin and trypsin genes and the activity of these proteases in M. anisopliae strains cannot be associated with the virulence against the two insect pests. Probably, subtilisin and trypsin enzyme production is not a vital factor for pathogenicity, but its contribution is important to the pathogenicity process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1813-1818
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• 2014

This paper presents the stability analysis of the haptic system including a human impedance using the Routh-Hurwitz criterion. The reflective force is computed from a virtual spring model and is transferred to a human operator using the first-order-hold method. The stability boundary conditions are induced and the relation among a virtual spring ($K_w$), the mass ($M_h$), the damping ($B_h$) and the stiffness ($K_h$) of a human impedance is analyzed. Hence the stability boundary of the virtual spring ($K_w$) is proposed as $K_w{\leq}54413{\sqrt{(M_h+M_d)(B_h+B_d)}}-0.486K_h$ when the sampling time is 1 ms. The average relative error is about 0.5% when the mathematical analysis results are compared with the results of the stability boundary model.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.14-22
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• 1990

For efficient use of solar energy in plastic greenhouse, thermal storage system was developed. The system was constructed with the counter-flow type air-water heat exchanger using a thin polyethylene film as a medium of heat exchange parts. Experiments were carried out to investigate the heat exchange rate, optimum water flow rate, overall heat transfer coefficient, and the effectiveness of the counter-flow type air-water heat exchanger with polyethylene film bags. Mathematical model to predict air temperature leaving heat exchanger was developed. The results obtained in the present study are summarized as follows. 1. Heat exchange rate in the counter-flow type air-water heat exchanger with polyethylene film bags was compared to that of polyethylene film. Heat exchange rate was almost identical at air velocity of 0.5m/s on polyethylene film surface. But, heat exchange rate of heat exchanger with polyethylene film bag was $32{\sim}55KJ/m^2$ hr higher than that of polyethylene film at air velocity of 1.0m/s. 2. Considering the formation of uniform water film and the sufficient heat exchange rate of polyethylene film bags, optimum water flow rate in polyethylene film bags was $3.0{\sim}6.0{\ell}/m^2$ min. 3. The overall heat transfer coefficient of polyethylene film bags was found to be $35.0{\sim}130.0KJ/m^2\;hr\;^{\circ}C$ corresponding to the air velocity ranging 0.5 to 4.0 m/s on polyethylene film surface. And the overall heat transfer coefficient showed almost linearly increasing tendency to the variation of air velocity. 4. Mathematical model to predict air temperature leaving the heat exchanger was developed, resulting in a good agreement between the experimental and predicted values. But, the experimental results were a little lower than predicted. 5. Effectiveness of heat exchanger for the experiment was found to be 0.40~0.81 corresponding to the number of transfer units due to the variation of air velocity ranging 0.6 to 1.7 m/s.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.96-112
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• 2002

In the present study, we have investigated the effects of centrally administered ginsenoside Rc or Rgl on the modulation of NMDA receptor and $GABA_A$ receptor binding in rat brain. The NMDA receptor binding was analyzed by quantitative autoradiography using $[^3H]MK-801$ binding, and $GABA_A$ receptor bindings were analyzed by using $[^3H]muscimol\;and\;[^3H]flunitrazepam$ in rat brain slices. Rats were infused with ginsenoside Rc or Rg1 ($10\;{\mu}g/10{\mu}l/hr$, i.c.v.) for 7 days, through pre-implanted cannula by osmotic minipumps (Alzet, model 2ML), The levels of $[^3H]MK-801$ binding were highly decreased in part of cortex and cingulated by ginsenoside Rc and Rgl. The levels of $[^3H]muscimol$ binding were strongly elevated in almost all regions of frontal cortex by the treatment of ginseoside Rc but decreased by ginsenoside Rg 1. However, the $[^3H]flunitrazepam$ binding was not modulated by ginsenoside Rc or ginsenoside Rgl infusion. These results suggest that prolonged infusion of ginsenoside could differentially modulate $[^3H]MK-801\;and\;[^3H]muscimol$ binding in a region-specific manner. Also, we investigated the influence of centrally administered ginsenoside on the regulation of mRNA levels of the family of NMDA receptor subtypes (NR1, NR2A, NR2B, NR2C) by in situ hybridization histochemistry in the rat brain. The level of NR1 mRNA is significantly increased in temporal cortex, caudate putamen, hippocampus, and granule layer of cerebellum in Rgl-infused rats as compared to control group. The level of NR2A mRNA is elevated in the frontal cortex. In contrast, it was decreased in CAI area of hippocampus in Rgl-infused rats. However, there was no significant change of NR1 and NR2A mRNA levels in Rc-infused rats. The level of NR2B mRNA is elevated in cortex, caudate putamen, and thalamus in both Rc- and Rg-infused rats. In contrast, NR2B level is decreased in CA3 in Rgl-infused rats. The level of NR2C mRNA is increased in the granule layer of cerebellum in only Rg1 but not Rc infused rats. These results show that structure difference of ginsenoside may diversely affect the modulation of expression of NMDA receptor subunit mRNA after infusion into cerebroventricle in rats.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.105-111
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• 1999

This paper presents experimental results on the electrical properties of hydrogenated amorphous carbon films(a-C:H) prepared by PECVD. DC conductance of a-C:H was measured as a function of temperatures in the range of 100 to 423K. We studied two a-C:H films: one was well explained by the Mott's Variable Range Hopping(VRH) rule, but the other sample did not follow it. However, the conduction data of second sample were well fitted to Shimakawa's Multi-Phonon Hopping(MPH) model according to which conductivity is proportional to $T^M$ with m=15-17. but, in our samples, m was 10-12. Also a-C:H showed several bias effects like relaxation of conductance, bias-dependent conductance and the change of conductance slope in 1n(${\sigma}{\sqrt{T}}$) vs. $T^{1/4}$ plot. In this study we interpret these data by bias-dependent detrapping model.

• Computers and Concrete
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• v.2 no.1
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• pp.55-77
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• 2005

The closed form solution of the equilibrium equations in the ultimate design of reinforced concrete sections under biaxial bending is presented. The stresses in the materials are described by the Model Code 1990 equations. Computation of the integral equations is performed generally in terms of all variables. The deformed shape of the section in the ultimate conditions is defined by Heaviside functions. The procedure is convenient for the use of mathematical manipulation programs and the results are easily included into nonlinear analysis codes. The equations developed for rectangular sections can be applied for other sections, such as T, L, I for instance, by decomposition into rectangles. Numerical examples of the developed model for rectangular sections and composed sections are included.

• Geomechanics and Engineering
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• v.1 no.3
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• pp.219-239
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• 2009

Vertical vibration tests were conducted using model footings of different size and mass resting on the surface of finite sand layer with different height to width ratios and underlain by either rigid concrete base or natural red-earth base. A comparative study of the ratio of predicted and observed natural frequency ratio of the finite sand stratum was made using the calculated values of equivalent stiffness suggested by Gazetas (1983) and Baidya and Muralikrishna (2001). Comparison of results between model footings resting on finite sand stratum underlain by the rigid concrete base and the natural red-earth base showed that, the presence of a finite base of higher rigidity increases the resonant frequency significantly. With increase in H/B ratio beyond 2.0, the influence of both the rigid concrete and natural red-earth base decreases. Increase in the contact area of the footing increases the resonant frequency of the model footings resting on finite sand stratum underlain by both the types of finite bases. Both the predicted and the observed resonant frequency ratio decreases with increase in force rating and height to width ratio for a given series of model footing.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.791-797
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• 2018

Objective: Trimethylation of histone 3 (H3) at 4th lysine N-termini (H3K4me3) in gene promoter region was the universal marker of active genes specific to cell lineage. On the contrary, coexistence of trimethylation at 27th lysine (H3K27me3) in the same loci-the bivalent H3K4m3/H3K27me3 was known to suspend the gene transcription in germ cells, and could also be inherited to the developed stem cell. In galline species, throughout example of H3K4m3 and H3K27me3 ChIP-seq analysis was still not provided. We therefore designed and demonstrated such procedures using ChIP-seq and mRNA-seq data of chicken follicular mesenchymal cells and male germ cells. Methods: Analytical workflow was designed and provided in this study. ChIP-seq and RNA-seq datasets of follicular mesenchymal cells and male germ cells were acquired and properly preprocessed. Peak calling by Model-based analysis of ChIP-seq 2 was performed to identify H3K4m3 or H3K27me3 enriched regions ($Fold-change{\geq}2$, $FDR{\leq}0.01$) in gene promoter regions. Integrative genomics viewer was utilized for cellular retinoic acid binding protein 1 (CRABP1), growth differentiation factor 10 (GDF10), and gremlin 1 (GREM1) gene explorations. Results: The acquired results indicated that follicular mesenchymal cells and germ cells shared several unique gene promoter regions enriched with H3K4me3 (5,704 peaks) and also unique regions of bivalent H3K4m3/H3K27me3 shared between all cell types and germ cells (1,909 peaks). Subsequent observation of follicular mesenchyme-specific genes-CRABP1, GDF10, and GREM1 correctly revealed vigorous transcriptions of these genes in follicular mesenchymal cells. As expected, bivalent H3K4m3/H3K27me3 pattern was manifested in gene promoter regions of germ cells, and thus suspended their transcriptions. Conclusion: According the results, an example of chicken H3K4m3/H3K27me3 ChIP-seq data analysis was successfully demonstrated in this study. Hopefully, the provided methodology should hereby be useful for galline ChIP-seq data analysis in the future.