• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.64 no.4
• /
• pp.303-307
• /
• 2015

The effects of additive such as $H_2O_2$ in KOH electrolyte solution for the Aluminum/Air fuel cell were investigated with regard to electric power characteristics. The power generated by a Al/Air fuel cell was controlled by the KOH electrolyte solution and $H_2O_2$ depolarizer. Higher cell power was achieved when higher KOH electrolyte concentration and higher $H_2O_2$ depolarizer amount. The maximum power was increased by the increase amount $H_2O_2$ depolarizer, it was found that $H_2O_2$ depolarizer inhibits the generation of hydrogen and the polarization effect was reduced as a result. Internal resistance analysis was employed to elucidate the maximum power variation. Higher internal resistance created internal potential differences that drive current dissipating energy. In order to improve the output characteristics of the Al/Air fuel cell, it is thought to be desirable to increase the KOH electrolyte concentration and increase the $H_2O_2$ addition amounts.

• Journal of Drive and Control
• /
• v.17 no.3
• /
• pp.15-25
• /
• 2020

The cycle time and power saving effect of a hydraulic hybrid injection molding machine using a servo motor are considered in this paper. In order to verify control characteristics, such as pressure and speed, experiments were performed with the hydraulic hybrid injection molding machine, clamping force of 110 ton. The power consumption and production cycle time of a conventional hydraulic injection molding machine were measured to compare its performances with the hydraulic hybrid injection molding machine. An injection molding machine with a clamping force of 1300 ton was used as the conventional machine, the hybrid machine was implemented by replacing its induction motors with servo motors. In the remodeled hybrid machine, experiments were performed to investigate how the displacement of the mold clamping pump affects the power consumption and production cycle time. The results showed that the production cycle time of the hybrid injection molding is similar to a conventional hydraulic injection molding machine but with a significant energy saving of about 40%.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.5
• /
• pp.342-348
• /
• 2021

The PV module of solar power systems requires maximum power point tracking (MPPT) technique because the power-voltage and current-voltage characteristics vary depending on the surrounding environment. In addition, the 120 Hz ripple voltage on the DC-Link is caused by the imbalance of the system voltage and current. The effect of this 120 Hz ripple voltage reduces the efficiency of the power generation system by increasing the output current distortion rate. Increasing the capacity of DC-Link can reduce the 120 Hz ripple voltage, but this method is inefficient in price and size. We propose a technique that detects 120 Hz ripple voltage and reduces the effect of ripple voltage without increasing the DC-Link capacity through a controller. The proposed technique was verified through simulations and experiments using a 1 kW single-phase solar power system. In addition, the proposed technique's feasibility was demonstrated by reducing the distortion rate of the output current.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.17 no.1
• /
• pp.29-34
• /
• 2011

Background: The purpose of this study was to investigate the effect of a Kinesio taping on muscle power and fatigue index in quadriceps femoris (vastus medialis, vastus lateralis, rectus femoris.). Methods: 15 male (heathy collegiate students) was enrolled from Kyungwoon university, Gumi. Kinesio tape was applied on quadriceps femoris muscle of subjects. Muscle power and fatigue index was measured by Wingate ergometer (warm-up was 30sec in 60W, maximum power test was 30sec in 100W, recovery was 30sec in 60W) in pre- and post applied taping. Results: As a results, there showed statistically significant improvement in mean power, peak power, mean power/kg, peak power/kg, fatigue index (p<.05). Conclusions: The study of Wingate test by applying Kinesio taping was significantly effected in mean power, peak power, mean power/kg, peak power/kg.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.7
• /
• pp.52-58
• /
• 2012

In this study, we have investigated the effect of the solar power generation facilities on the power quality of interconnected solar power generation system. When the solar power generation facility was connected to the distribution system, whether the solar power generation is under operation or not, Peak factor of current was increased to 0.033[%], Frequency is deviated from $60{\pm}0.2$[Hz] and also Short term flicker indication($P_{st}$) increased to 0.213[p.u.] compare with the disconnected situation. Harmonic current [%] in orders was 11.42[%] maximum under 11th orders and was 7.861[%] between 11th and 17th orders. These values were about 3 or 4 times compared with "the power system interconnection technique standards" at the same situation above. Therefore, we could confirmed that the solar power generation facility, when it was connected to the existing distribution system, made bad influence on the power qualities such as the peak factor of current, frequency regulation, short term flicker indication($P_{st}$) and harmonic current [%] in orders etc.

• Wind and Structures
• /
• v.21 no.6
• /
• pp.727-753
• /
• 2015

A double-skinned composite tubular (DSCT) wind power tower was suggested and automatic section design software was developed. The developed software adopted the nonlinear material model and the nonlinear column model. If the outer diameter, material properties and design capacities of a DSCT wind power tower are given, the developed software performs axial force-bending moment interaction analyses for hundreds of sections of the tower and suggests ten optimized cross-sectional designs. In this study, 80 sections of DSCT wind power towers were designed for 3.6 MW and 5.0 MW turbines. Moreover, the performances of the 80 designed sections were analyzed with and without considerations of large displacement effect. In designing and analyzing them, the material nonlinearity and the confining effect of concrete were considered. The comparison of the analysis results showed the moment capacity loss of the wind power tower by the mass of the turbine is significant and the large displacement effect should be considered for the safe design of the wind power tower.

• Korean Management Science Review
• /
• v.32 no.2
• /
• pp.37-50
• /
• 2015

The number of contracts for bundling services in a domestic telecommunication market records 1.3 miilion as of the first half year in 2007, and steadily increased to 8.97 million in 2010, to 12.76 million in 2013. In 2014, 70.4% of telecommunication service consumers are found to subscribe to bundling service. Bundling services provide consumers with benefits such as price discount, convenience, increase ARPU. However, a market dominant player in a specific market may transfer its market power to another market by selling bundling services. SSNIP has been adopted to provide a market definition. However, SSNIP is not suitable to measure the effect of market power transition through bundling services because SSNIP cannot measure the effect of changeover sales of bundling services. Thus, in this study, we have investigated the effect of market power transition through bundling services reflecting market power effect and quality upgrade using Gross Upward Market Power Pressure Index metho and reviewed UPP and derivative UPP models.

• Advances in nano research
• /
• v.14 no.5
• /
• pp.463-474
• /
• 2023

The purpose of this paper is to present the analysis of propagating and evanescent waves in functionally graded (FG) nanoplates with the consideration of nonlocal effect. The analytical integration nonlocal stress expansion Legendre polynomial method is proposed to obtain complete dispersion curves in the complex domain. Unlike the traditional Legendre polynomial method that expanded the displacement, the presented polynomial method avoids employing the relationship between local stress and nonlocal stress to construct boundary conditions. In addition, the analytical expressions of numerical integrations are presented to improve the computational efficiency. The nonlocal effect, inhomogeneity of medium and their interactions on wave propagation are studied. It is found that the nonlocal effect and inhomogeneity of medium reduce the frequency bandwidth of complex evanescent Lamb waves, and make complex evanescent Lamb waves have a higher phase velocity at low attenuation. The occurrence of intersections of propagating Lamb wave in the nonlocal homogeneous plate needs to satisfy a smaller Poisson's ratio condition than that in the classical elastic theory. In addition, the inhomogeneity of medium enhances the nonlocal effect. The conclusions obtained can be applied to the design and dynamic response evaluation of composite nanostructures.

• Korean journal of food and cookery science
• /
• v.11 no.2
• /
• pp.98-103
• /
• 1995

The effect of blanching time, blanching water and power settings of microwave oven on the minerals retention in spinach and broccoli were investigated. The vegetables were blanched for 60, 120 and 180 sec, with water 0ml, 50ml and 100ml every 100 g of raw material at two different power settings (700w, 400w). The retention of minerals(Ca,K,Mg,Cu,Fe,Na,p) in spinach and broccoli were higher at the 400w power than 700w power level, regardless of blanching time. At the high power, the retention of minerals in spinach and broccoli were reduced remarkably as the blanching time increased. The reason for this is that the increasing power level results in greater water coming ou from the vegetable. Also, minerals in vegetable as coming out with this water loss in proportion to the blanching time.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.453-454
• /
• 2011

With the transmission line the ratio of lightning breakdown the while whole breaking down is occupying a high share with average 72%, is a tendency which increases continuously. In order decreasing the back flashover faults from like this lightning breakdown, it is very important to maintain grounding resistance of tower below target. In this paper, we synthetically analyzed the grounding resistance reduction effect of tower foundation and standard ground connection from construction site, and investigated efficiency for ways to increase the length of counter poise and expand the size of conductivity concrete materials.