• 전자공학회논문지 IE
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• v.45 no.1
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• pp.31-37
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• 2008

A Wibro RF down converter of 2.3GHz band is designed and implemented in this paper. The problems that can occur in the receiver LNA(Low Noise Amplifier) to minimize additional purposes. In addition, 2.3GHz band from the 75 MHz downward to minimize the losses in the process, transform and improve efficiency, and achieve stable characteristics can be used to make high frequency characteristics of the device. Wibro repeater uses a TDMA(Time Division Multiplexing Access) method is needed because the RF switch. Production criterion specification, the input voltage from +8 V 1.2A of current consumption, 60dB gain and the noise figure of less than 2.5dB, VSWR(Voltage Standing Wave Ratio) less than 1.5, more than IMD(Inter Modulation Distortion) 60dB satisfied. Environmental conditions ($-20^{\circ}C$ to $70^{\circ}C$) to pass the test of reliability in a long time, that seemed crafted Wibro down converter be applied to the Wibro repeater.

• Journal of the Korean Society of Food Culture
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• v.22 no.4
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• pp.475-481
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• 2007

This study was carried out to determine the quality characteristics of Jeju mandarin orange jelly with various gelling agent such as agar, ${\kappa}-carrageenan$ and gellan gum for the aged. The concentration of agar was 0.4-0.6% and that of ${\kappa}-carrageenan$ and gellan gum was 0.2-0.4%. The color value, gelling temperature, melting temperature, break down rate, textural properties and sensory acceptance test of Jeju mandarin orange jelly with various gelling agent were measured. Average age of the subjects for acceptance test was 78.23. Redness and yellowness of Jeju mandarin orange jelly with agar was lower than that with ${\kappa}-carrageenan$. The gelling and melting temperature of Jeju mandarin orange jelly with agar was lowest among the jellies. Break down rate of Jeju mandarin orange jelly with agar was highest among the jellies. Above results showed that the stability of Jeju mandarin orange jelly with agar was inferior than that with ${\kappa}-carrageenan$ and gellan gum. Hardness, adhesiveness and springiness of Jeju mandarin orange jelly with agar was lowest among the jellies and sensory acceptance of Jeju mandarin orange jelly with gellan gum was highest among them. Thus, gellan gum was appropriate gelling agent for the Jeju mandarin orange jelly with regard to the acceptability and the depression of sour taste in Jeju mandarin orange jelly could improve the acceptability for the aged.

• Korean journal of food and cookery science
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• v.23 no.6
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• pp.891-898
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• 2007

This study was carried out to determine the quality characteristics of grape jellies made with various gelling agents such as agar, $\kappa$-carrageenan, and gellan gum for consumption by elderly women. The concentrations of agar were 0.25, 0.35, and 0.45%, and those of the $\kappa$-carrageenan and gellan gum were 0.15, 0.3, and 0.4%, respectively. The color values, gelling temperatures, melting temperatures, break down rates, textural properties, and consumer acceptance of the grape jellies were measured. The average age of the subjects participating in the acceptance test was 82. The lightness of the grape jelly made with agar was the highest, and its redness was the lowest among the jellies. The gelling and melting temperatures for the grape jelly made with gellan gum were higher than those of the other jellies, and the melting temperatures were 37, 43, and $47^{\circ}C$ based on 0.15, 0.3, and 0.4% gellan gum content, respectively. The break down rate of the grape jelly made with gellan gum was the lowest among the jellies. These results indicate that the stability of the grape jelly made with gellan gum was superior among the jellies. The hardness, adhesiveness, and springiness of the grape jelly made with agar were lowest among the jellies, and the grape jellies made with agar(0.25% and 0.35%) and gellan gum(0.15% and 0.3%) had the highest consumer acceptance among the jellies. However, the gellan gum was deemed an inappropriate gelling agent with regard to the acceptability due to its sour and moldy taste as perceived by the participants.

• Journal of Environmental Impact Assessment
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• v.12 no.2
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• pp.73-86
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• 2003

In this study, we performed 8 times of water quality sampling and continuous measurement of flow to identify wastewater flow characteristics for wastewater treatment basins of Namyangju city. The field survey has been conducted 6 times in dry weather period and 2 times in wet weather period. Each survey conducted 24-hr water quality sampling in the interval of 2-hr. From the analysis of flow data and water quality data, the following conclusions can be drawn. For Namyangju-1 station, which represents residential and commercial mixed area, flow rises early in the morning before office-going hour and moves up and down within narrow range, and lasted after office-leaving hour, resulting from continuous commercial activity. In case of Namyangju-5 station representing community and Namyangju- 6 station representing residential area, the flow immediately falls down after rising early in the morning and later rises again at the office-leaving hour, and arrives at peak flows around late evening. In the analysis of wastewater characteristics for weekdays and weekends, without landuse types the flow rate of weekends is higher than that of weekdays because it reflects population, being not contributed to generate wastewater during the working hours of weekdays, stay home and produce wastewater for weekends period.

• Preventive Nutrition and Food Science
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• v.11 no.4
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• pp.348-357
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• 2006

Nano is a unit that designates a billionth; accordingly nanotechnology could be described as the study and applications of the unique characteristics and phenomena of nanometer size materials. Applications of nanotechnology fall into two categories (one is top-down and the other is bottom-up). Currently, most products are the results of the top-down approach. Nanofoods have distinct functional characteristics stemming from the size, mass, chemical combinations, electrolytic features, magnetic properties of food sources at the nano level and which can be applied for safe absorption and delivery into the body. The greatest advantage of nanofood is that it permits the efficient use of small quantities of nutritional elements by increasing digestive absorption ability and by delivering natural elements without any change in their original characteristics. On the other hand, there are still unsolved problems, such as questions about safety and introduction of harmful material. The demand for new commercial food products is increasing, and commercial food producers are gradually combining nanotechnology and traditional food preparation methods. Nanofoods will improve our eating habits remarkably in the future. Tomorrow we will design nanofoods by shaping molecules and atoms. It will have a big impact on the food and food-processing industries. The future belongs to new products and new processes with the goals of customizing and personalizing consumer products. Nanotechnology is expected to be applied to not only foods themselves, but also to food packaging, production, safety, processing and storage. Also, it is believed that nanotechnology will be applied tracking finished products back to production facilities and even to specific processing equipment in those facilities. The aim of this study is the introduction of technology, applications, products, markets, R&D, and perspectives of nanofoods in the food industry.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.142-149
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• 2004

PMLSM(Permanent Magnet linear Synchronous Motor) has widely applied to industrial automations, machine tools and semiconductor equipments due to the merit on the reduction of noise, vibration and the superior dynamic characteristics in comparison to the conventional method, which uses mechanical transfer equipments. Especially, in the case of applying to Z-axis operation structure, control system needs the method of an initial angle setting and the improvement of up/down operation characteristics. This paper proposes an initial angle setting algorithm and a variable gain schedule using real speed and moving direction to improve up/down operation characteristics. The effectiveness of proposed algorithms Is demonstrated by comparing to a conventional gain system via 4-point absolute positions profile with each velocity, acceleration and deceleration.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.355-370
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• 2020

We conducted a field survey to analyze the ecological structure and spatial distribution of microplankton (phytoplankton and ciliates) in relation to water masses at 21 stations on the surface and chlorophyll-a maximum layers (CML) in the Northern East China Sea (nECS; 32°-33°N; 124°00'-127°30'E) from August 3 to August 6, 2019. The results showed that the water masses were divided into Chinese Coastal Waters (CCW) and the Tsushima Warm Current (TWC). The CCW showed the environmental characteristics of high temperature and low salinity, and the TWC showed high temperature and high salinity. The characteristics of the phytoplankton community in the CCW showed various community structures related to the nutrients supplied from the large rivers of the Chinese continent. However, the TWC had simple community structures because it originated near the equator and moved northward. The standing crops of phytoplankton and ciliates were very high in the CCW but showed low at the TWC. In particular, from the higher standing crops of protozoa than plant plankton at the TWC, the energy flow at the lower tropic levels caused by the microbial loop that fed on heterotrophic bacteria played an important role in the production of resource organisms. In other words, the marine ecological structure of the nECS in summer could be estimated as a bottom-up system at the CCW and a top-down system at the TWC.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.159-165
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• 2021

Electronic devices used in the mobile environments fabricated under the plasma conditions in high vacuum system. Especially for the development of advanced electronic devices, high quality plasma as the process conditions are required. For this purpose, the variable conductance throttle valves for controllable plasma employed to the high vacuum system. In this study, we analyzed the effects of throttle valve applications on vacuum characteristics simulated to obtain the optimum design modelling for plasma conditions of high vacuum system. We used commercial simulator of vacuum system, VacSim(multi) on this study. Reliability of simulator verified by simulation of the commercially available models of high vacuum system. Simulated vacuum characteristics of the proposed modelling agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve schematized as the modelling of throttle valve for the constant process-pressure of below 10-3 torr. Simulation results plotted as pump down curve of chamber, variable valve conductance and conductance logic of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably in plasma process.

• Proceedings of the KIEE Conference
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• summer
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• pp.1199-1201
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• 2004

When The temperature of the joining of SCR rises major changes of characteristics are increase of leakage current, decrease of break-down voltage, and increase of turn off time. Because these changes promote the inferiority of SCR it(SCR) will get out of control and its life time will be shortened and finally it will be destroyed. In this paper, we will measure the changes of the characteristics in accordance with a rise in temperature. On the basis of the result we will find out the appropriate time to change SCR and we will use the result for the maintenance of SCR and increase of reliability of SCR.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.434-436
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• 2000

In this study, we investigate the optical characteristics of merocyanine dye Langmuir-Blodgett(LB) film using the oscillation characteristics of quartz crystal. As results, the resistance and frequency shift at the parallel resonance under the UV irradiation is to be going down. This behaviour of resistance and frequency is different from the case of general mass adsorption into the organic film on the quartz crystal. Generally the frequency decrease of quartz crystal oscillator, which has been considered as mass loading, goes along with the resistance increase. Thus it has been suggested that the J-aggregate dissociation in merocyanine dye LB film by UV irradiation give rise to transformation of oscillation characteristics of quartz crystal.