• Mycobiology
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• v.41 no.1
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• pp.63-66
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• 2013

This study was conducted to identify a suitable color of light for development of the fruit body in Hypsizygus marmoreus. To accomplish this, samples were irradiated with blue (475 nm), green (525 nm), yellow (590 nm), or red (660 nm) light emitting diodes (LEDs) to induce the formation of fruiting bodies after mycelia growth. The diameter and thickness of the pileus and length of stipes in samples subjected to blue LED treatment were similar to those of subjected to fluorescent light (control), and the lengths of the stipes were highest in response to treatment with the red LED and darkness. The commercial yields of plants subjected to blue and green LED treatment were similar to those of the control. In conclusion, cultivation of H. marmoreus coupled with exposure to blue LED is useful for inducing high quality fruit bodies as well as higher levels of ergosterol, DPPH radical scavenging activity, total polyphenol content and reducing power.

• Journal of Drive and Control
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• v.9 no.3
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• pp.23-28
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• 2012

In this study the flow rate-to-pressure difference characteristics of short-tube type damping orifices for an aircraft door damper were investigated by CFD analyses and experiments. As the design parameters of the damping orifice its diameter, inlet and outlet angle, tube length and the viscosity of the working fluid were taken into consideration. The results showed that the discharge coefficient of the orifices are dependant on the inlet and outlet angle and the oil viscosity, while their length plays an little significant role. Although the short-tube type damping orifice was employed to induce a turbulent flow, their discharge coefficient decreases rapidly as the oil viscosity gets higher than 50mm2/s. Therefore, in order to determine the orifice size, satisfying the working temperature range of the door damper, the oil viscosity as well as the friction force on the damper piston should be kept within proper values. For the verification of the CFD analysis results the actual performance of a door damper was measured and compared with them.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.53-53
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• 2008

Piezoelectric transformers have been widely used such as DC-DC convertor, invertor, Ballast, etc. Because, the y have some merits compared with electro-magnetic transformers such as step-up ratio, high efficiency, small size and lg hit weight, etc. Piezoelectric transformer require high electromechanical coupling factor kp in order to induce a large out put power in proportional to applied electric field. And also, high mechanical quality factor Qm is required to prevent mechanical loss and heat generation. In general, PZT system ceramics should be sintered at high temperatures between 1200 and $1300^{\circ}C$ in order to obtain complete densification. Accordingly, environmental pollution due to its PbO evaporation. Hence, to reduce its sintering temperature, various kinds of material processing methods such as hot pressing, high energy mill, liquid phase sintering, and using ultra fine powder have been performed. Among these methods, liquid phase sintering is basically an effective method for aiding densification at low temperature. In this study, In order to comparis on low temperature sintering and solid state sintering piezoelectric transformers, rosen type transformers were fabricated u sing two PZT ceramics compositions and their electrical properties were investigated.

• Journal of Magnetics
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• v.21 no.2
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• pp.159-163
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• 2016

Antiferromagnet (AFM)/ferromagnet (FM) bilayer structures are widely used in the magnetic devices of sensor and memory applications, as AFM materials can induce unidirectional anisotropy of the FM material via exchange coupling. The strength of the exchange coupling is known to be sensitive to quality of the interface of the AFM/FM bilayers. In this study, we utilize proton irradiation to modify the interface structures and investigate its effect on the magnetic properties of AFM/FM structures, including the exchange bias and magnetic thermoelectric effect. The magnetic properties of IrMn/CoFeB structures with various IrMn thicknesses are characterized after they are exposed to a proton beam of 3 MeV and $1{\sim}5{\times}10^{14}ions/cm^2$. We observe that the magnetic moment is gradually reduced as the amount of the dose is increased. On the other hand, the exchange bias field and thermoelectric voltage are not significantly affected by proton irradiation. This indicates that proton irradiation has more of an influence on the bulk property of the FM CoFeB layer and less of an effect on the IrMn/CoFeB interface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.479-482
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• 1999

Cured epoxy resins are extensively used for the electrical insulation in high-voltage equipments. The bisphenol A-based epoxy resins lured with azine show, especially, good thermal properties and mechanical resistances. For the technical and economic reasons, varing amount of inorganic fillers are added to endow the required special properties. In the large generators and motors of power plants, epoxy insulation is disclosed to the harsh conditions like the superheated steam and abrupt temperature variation. Hygrothermal aging at elevated temperatures tends to induce degradation in epoxy resins. To predict the effect of this degradation in DGEBA/MDA/SN/zeolite system, we proceeded the forced moisture absorption experiment using the autoclave. The thermal properties of the untreated and treated specimens were analyzed by DSC and TGA under the nitrogen flowing condition. The moisture absorption results showed a weight increase during hygrothermal aging at 1207. At the initial aging period, the system leaded to more or less postcuring but more prolonged environmental aging leaded the discoloration of specimen and lowering the T$_{g}$./.

• Mycobiology
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• v.45 no.4
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• pp.409-420
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• 2017

Foliar sprays of three plant resistance inducers, including chitosan (CH), potassium sorbate (PS) ($C_6H_7kO_2$), and potassium bicarbonates (PB) ($KHCO_3$), were used for resistance inducing against Erysiphe cichoracearum DC (powdery mildew) infecting okra plants. Experiments under green house and field conditions showed that, the powdery mildew disease severity was significantly reduced with all tested treatments of CH, PS, and PB in comparison with untreated control. CH at 0.5% and 0.75% (w/v) plus PS at 1.0% and 2.0% and/or PB at 2.0% or 3.0% recorded as the most effective treatments. Moreover, the highest values of vegetative studies and yield were observed with such treatments. CH and potassium salts treatments reflected many compounds of defense singles which leading to the activation power defense system in okra plant. The highest records of reduction in powdery mildew were accompanied with increasing in total phenolic, protein content and increased the activity of polyphenol oxidase, peroxidase, chitinase, and ${\beta}$-1,3-glucanase in okra plants. Meanwhile, single treatments of CH, PS, and PB at high concentration (0.75%, 2.0%, and/or 3.0%) caused considerable effects. Therefore, application of CH and potassium salts as natural and chemical inducers by foliar methods can be used to control of powdery mildew disease at early stages of growth and led to a maximum fruit yield in okra plants.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.846-853
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• 2014

High performance intake silencer with low pressure drop are developed for a household oxygen generator. First, the acoustic power of the target oxygen generator are experimentally evaluated according to ISO code. Then, the transmission loss of and the flow characteristics inside the existing intake silencer are predicted and analyzed. On a basis of these results, two intake silencers are proposed, which are designed to induce the swirling flow inside the intake silencer and thus to reduce the flow loss. The predicted TL and the pressure drop for these two new silencers are compared to the existing one, which shows that the proposed ones have higher TL as well as low pressure drop. The reason for these improvements are explained by investigating the flow characteristics of the new silencers in detail.

• Korean Journal of Metals and Materials
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• v.48 no.6
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• pp.514-522
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• 2010

Graphite epoxy composite material (GECM) shows high specific strength and its application in the aerospace industry is gradually increasing. However, its application would induce galvanic corrosion between GECM and metallic materials. This work focused on the effects of anodizing and thermal oxidation on galvanic corrosion in a 3.5% NaCl solution between GECM and aluminium and titanium. In the case of anodized aluminium, galvanic corrosion resistance to the GECM was greatly improved by the anodizing treatment regardless of area ratio. In the case of anodized titanium, the anodizing by a formation voltage of 50V increased corrosion resistance of titanium in galvanic tests. Thermal oxidation of titanium also improved corrosion resistance of Ti to GECM.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.15-20
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• 2019

As industry is progressing and standards of living are improved, the demand of electrical energy is expected to grow 8-9% annually. Therefore, the importance of electrical fire prevention technology with the ability of the power supply is being emphasized. According to the statistics of fire in Korea, fire occurred about 45,000 cases annually, and electrical fire possessed about 20%. The electrical fire by poor contact has increased gradually, can be connected as great fire to secondarily induce short circuit and earth fault. Then analysis of heating causes of electrical connections between copper and copper alloy is needed. Also, detection and analysis algorithm of oxide at copper alloy are necessary. In this research, in order to understand the characteristics of oxide growth with rising resistance and heating, it is demonstrated that the oxide at electrical connections can cause fire due to arcing.

• PNF and Movement
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• v.12 no.1
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• pp.45-50
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• 2014

Purpose: Deficits in upper-extremity function in individuals with tetraplegia are primarily due to the loss of motor pathways. The purpose of this case report is to describe the effect of closed kinetic chain exercise using PNF on hand function and ADL of patient with incomplete spinal cord injure. Methods: Patient was a 53-year-old man with C4 tetraplegia and hand and upper extremity impairment who participated in this training intervention for 10 weeks. Results: Patient demonstrated improvements in upper extremity strength, hand function and performance of ADL. Outcome measures(ASIA motor scale, Hand power, Jebsen-Taylor Hand Function test, SCIM) were measured before and after the training program. Conclusion: The results of this case suggests that an closed kinetic chain exercise program in incomplete spinal cord injury patient may induce Hand function and ADL.