• Title/Summary/Keyword: AT feeding systems

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Compact Rectenna System Design Using a Direct Impedance Matching Method (임피던스 직접 정합 방법에 의한 Rectenna 시스템 소형화 설계)

  • Choi, Taemin;Han, Sang-Min
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.3
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    • pp.286-291
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    • 2013
  • In this paper, a compact rectenna system is designed using a circular sector antenna with harmonic-rejecting characteristics and a direct impedance matching method. The system is designed with bandpass filtering performed by the harmonic-rejection of the circular sector antenna and without impedance matching circuit for the diodes by the direct impedance matching technique. Therefore, while the rectifying circuit of the proposed system can be implemented without a bandpass filter and a impedance matching circuit, it is integrated on the back side of the antenna using precise fabrication techniques for coaxial feedings without degrading the system performances corresponding to the feeding points. From the experimental results, the optimized rectenna system has presented excellent performances of a conversion efficiency of more than 52 % and a conversion voltages of more than 1.5 V at 2.5 GHz.

PRODUCTION FROM FINE WOOL SHEEP IN THREE AREAS IN NORTHERN CHINA

  • Masters, D.G.;Purser, D.B.;Yu, S.X.;Wang, Z.S.;Yang, R.Z.;Liu, N.;Wang, X.L.;Lu, D.X.;Wu, L.H.;Rong, W.H.;Ren, J.K.;Li, G.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.3 no.4
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    • pp.305-312
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    • 1990
  • The seasonal changes in production, the systems of management and the seasonal climatic and feeding conditions are described for three farms representative of the major areas for growing fine-wool sheep in northern China. At all farms, summer and autumn were seasons of rapid liveweight gain and wool growth. In the winter and spring, during lactation, liveweight declined wool growth decreased by approximately 70%, and fibre diameter by 4 to 8 microns. The wool produced was characterized by a very low clean wool yield (39-51%). Greasy fleece weights ranged from 4.5 to 8.0 kg and average diameter of wool fibres from 20.5 to 23 microns. The number of lambs born per 100 ewes mated ranged from 79 to 95, lamb weights ranged from 3.8 to 4.5 kg, and weaning weights ranged from 17 to 25 kg. Overall, the patterns of sheep production were similar to those found in seasonally arid environments (such as in the mediterranean climatic zone). Yield of clean wool and therefore clean fleece weights were far below those in most other fine-wool producing areas of the world.

Effects of Dietary Supplemented Inorganic and Organic Selenium on Antioxidant Defense Systems in the Intestine, Serum, Liver and Muscle of Korean Native Goats

  • Chung, J.Y.;Kim, J.H.;Ko, Y.H.;Jang, I.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.1
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    • pp.52-59
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    • 2007
  • The present study was designed to assess whether dietary inorganic and organic selenium (Se) could affect antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GST), and the level of malondialdehyde (MDA), a marker of lipid peroxidation, in the intestine, serum, liver, and gastrocnemius muscle of Korean native goats. A total of eighteen Korean native goats was allotted into three dietary groups, consisting of basal diet (CON), or basal diet with either 0.25 ppm inorganic (IOSEL) or 0.25 ppm organic Se (ORSEL), and fed the corresponding diets for 5 wks. Growth performance, including body weight and total gain, and blood biochemical profiles, including GSH-Px, were not significantly different between the three dietary groups. Also, the specific activities of SOD, GSH-Px, and GST, and the level of MDA in the intestinal mucosa and liver from goats were not substantially affected by either inorganic Se or organic Se. However, goats fed the diet containing organic Se showed a significant increase in GSH-Px and GST activities in the gastrocnemius muscle compared with those fed the basal diet. In conclusion, increased muscle GSH-Px and GST activities suggest that dietary organic Se may affect, at least in part, the antioxidant defense system in muscle of Korean native goats under the conditions of our feeding regimen.

Effects of Dietary Proteins and Inositol Hexaphosphate on the Preneoplastic Lesions and Antioxidant Enzymes of Hepatocellular Carcinogenesis in Rats (식이 단백질의 종류 및 Inositol Hexaphosphate가 간세포 암화과정에서 전암성 병변의 지표 및 항산화 효소계에 미치는 영향)

  • 김현덕;최혜미
    • Korean Journal of Community Nutrition
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    • v.4 no.2
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    • pp.239-247
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    • 1999
  • Six-week-old Sprague Dawley rats were fed the diets of 20% casein or soy protein. Two weeks after the feeding, hepatocellular chemical carcinogenesis was initiated by diethylnitrosamine(DEN), and promoted by the diet containing 0.01% 2-acetylamino-fluorene(AAF) and two-thirds partial hepatectomy(PH). The animals were sacrificed at 8 weeks after the DEN injection. The area of placetal glutathione S-trnasferase(GST-P) positive foci, the activities of several enzymes in cellualr antioxidant enzyme systems and glucose 6-phosphatase were determined to investigate the mechanism of the anticarcinogenic effect by the dietary proteins. In another set of experiments, the drinking water of rats fed casein was supplemented with 1.5% inositol hexaphosphate(InsP6) to elucidate whether it has the comparable anticancer action of soy protein. The area and number of GST-P positive foci in the soy protein group were significantly(p<0.05) lower than those inthe casein group. The livers of rats fed casein showed moderate fattydegeneration and larger hyperplastic nodules than those of rats fed soy protein. In another set of experiments, the area and number of GST-P positive foci in the rats fed casein supplemented with InsP6 were not significantly different from those in the rats fed casein or soy protein. The lipid peroxidation of rats fed different protein sources showed no significant difference. Glutathione S-transferase(GST) activities were increased significantly(p<0.05) by carcinogen treatment in all dietary groups. Glucose 6-phosphatase(G6Pase) activities were decreased by carcinogen treatment, and hence showed a reverse relationship(r=-0.695, p<0.01) to the GST-P positive foci. Therefore, the activities in the rats fed casein were lower than those in the rats fed soy protein. These results suggest that the soy protein seems to be more anti-carcinogenic than casein by decreasing the preneoplastic lesion and by increasing the membrane stability but inositol hexaphosphate, a component of soy protein, may not be protective against hepatocarcinogenesis.

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Trace Mineral Nutrition in Poultry and Swine

  • Richards, James D.;Zhao, Junmei;Harrell, Robert J.;Atwell, Cindy A.;Dibner, Julia J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.11
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    • pp.1527-1534
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    • 2010
  • Trace minerals such as zinc, copper, and manganese are essential cofactors for hundreds of cellular enzymes and transcription factors in all animal species, and thus participate in a wide variety of biochemical processes. Immune development and response, tissue and bone development and integrity, protection against oxidative stress, and cellular growth and division are just a few examples. Deficiencies in trace minerals can lead to deficits in any of these processes, as well as reductions in growth performance. As such, most animal diets are supplemented with inorganic and/or organic forms of trace minerals. Inorganic trace minerals (ITM) such as sulfates and oxides form the bulk of trace mineral supplementation, but these forms of minerals are well known to be prone to dietary antagonisms. Feeding high-quality chelated trace minerals or other classes of organic trace minerals (OTM) can provide the animal with more bioavailable forms of the minerals. Interestingly, many, if not most, published experiments show little or no difference in the bioavailability of OTMs versus ITMs. In some cases, it appears that there truly is no difference. However, real differences in bioavailability can be masked if source comparisons are not made on the linear portion of the dose-response curve. When highly bioavailable chelated minerals are fed, they will better supply the biochemical systems of the cells of the animal, leading to a wide variety of benefits in both poultry and swine. Indeed, the use of certain chelated trace minerals has been shown to enhance mineral uptake, and improve the immune response, oxidative stress management, and tissue and bone development and strength. Furthermore, the higher bioavailability of these trace minerals allows the producer to achieve similar or improved performance, at reduced levels of trace mineral inclusion.

Hormonic Evaluation of An Imported IAT(Intra Airport Transit) System in Incheon International Airport (인천 국제공항청사 경전철 도입에 따른 고조파 영향 분석)

  • Kim, Jin-O;Song, Hak-Seon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.1
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    • pp.41-47
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    • 2006
  • This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used for electric vehicles with 80[kW] per car produced by Mitsubishi Heavy Industries Ltd, and which is constructed with SIV(Static Inverter), VVVF controller and two induction motor. The vehicles operated in the IAT system can be treated as rapidly changing DC loat and at a feeding substation, 3-phase electric power is transferred to DC 750[V] by rectifier. Since vehicles are changing continuously, the voltages for the load fluctuate in the IAT system, and moreover, the voltage fluctuation generates high-order harmonics. It results the difficulty in maintaining power quality in KEPCO systems' side. The power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper. The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

Performance Evaluation of Hydrogen Peroxide Vaporizer with $K_2MnO_4/Al_2O_3$ Catalyst ($K_2MnO_4/Al_2O_3$촉매를 이용한 과산화수소 기화기의 성능평가)

  • Rang Seong-Min;An Sung-Yong;Kwon Hyuck-Mo;Kwon Se-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.329-334
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    • 2005
  • The rocket grade hydrogen peroxide has been widely used as a monopropellant in propulsion systems. Conventional decomposition of hydrogen peroxide, however, requires preheating before feeding into the reactor. In the present paper, we described an experimental study of a catalytic reactor bed that employs multiple catalysts to enhance the low temperature response in the vicinity of the reactor inlet. $K_2MnO_4$ is experimentally chose as the inlet catalyst from the candidates of silver, platinum, $La_{0.8}Sr_{0.2}CoO_3(LSC),\;and\;K_2MnO_4$. We developed new synthesis and coating method using modified alumina sol-gel method to strengthen the adhesion of $K_2MnO_4$ catalyst. from the vaporizer experiment with hydrogen peroxide at room temperature, satisfactory vaporizing performance was measured.

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Study on the Development Trend of Pressurization System for Propulsion System of Launch Vehicle (발사체 추진기관 가압시스템 개발 사례 연구)

  • Shin, Dong-Sun;Kim, Byung-Hun;Han, Sang-Yeop
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.721-724
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    • 2011
  • A system to pressurize propellants stored in propellant tanks is necessary to feed liquid-propellants into combustion devices at the required pressure and flowrate without having cavitation in turbo-pumps. A pressurization system can be categorized into pre-pressurization stage and main-pressurization stage. This report is regarding to a main-pressurization system. Pressurization methods for propellant tanks are divided into pressurant gas generating method and pressurant gas feeding method. One of pressurant gas generating methods uses the vaporized oxygen gas from cryogenic liquid oxygen and non-flammable gas. In this report, both advantages and disadvantages for pressurization methods and types of pressurization systems are compared. Especially the characteristics and principle of pressurization system using impulsive control strategy applied in launch vehicles are introduced. Additionally the structure, schematics, and specifications of heat exchanger, which is one of main units in pressurization system are also discussed. This paper can be utilized to generate the conceptual requirements and to design preliminary configuration of pressurization system during the development of launch vehicle.

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Design of High Efficiency Switching Mode Class E Power Amplifier and Transmitter for 2.45 GHz ISM Band (2.45 GHz ISM대역 고효율 스위칭모드 E급 전력증폭기 및 송신부 설계)

  • Go, Seok-Hyeon;Koo, Kyung-Heon
    • Journal of Advanced Navigation Technology
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    • v.24 no.2
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    • pp.107-114
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    • 2020
  • A power amplifier of 2.4 GHz ISM band is designed to implement a transmitter system. High efficiency amplifiers can be implemented as class E or class F amplifiers. This study has designed a 20 W high efficiency class E amplifier that has simple circuit structure in order to utilize for the ISM band application. The impedance matching circuit was designed by class E design theory and circuit simulation. The designed amplifier has the output power of 44.2 dBm and the power added efficiency of 69% at 2.45 GHz. In order to apply 30 dBm input power to the designed power amplifier, voltage controlled oscillator (VCO) and driving amplifier have been fabricated for the input feeding circuit. The measurement of the power amplifier shows 43.2 dBm output and 65% power added efficiency. This study can be applied to the design of power amplifiers for various wireless communication systems such as wireless power transfer, radio jamming device and high power transmitter.

Design of Coupled-line Band-pass Filter Using New Equivalent Circuit of Tapped-line (탭 선로의 새로운 등가 회로를 이용한 결합 선로 대역 통과 필터 설계)

  • Lee, Il-Woo;Han, Seung-Hyun;Yun, Tae-Soon;Kwoun, Sung-Su;Hong, Tae-Ui;Lee, Jong-Chul
    • 한국ITS학회:학술대회논문집
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    • v.2006 no.10
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    • pp.187-190
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    • 2006
  • In this paper, the equivalent circuit of tapped-line that is applied in the feeding of the band-pass filter with high coupling is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and additional transmission line, and the electrical lengths of stub and line can be obtained by the impedance of resonator and the inverter. The new equivalent circuit of tapped-line can be simply applied of design of band-pass filter and leads to very good agreement compared with theoretical value. The coupled-line band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.97 dB and the return loss of 18.5 dB at the center frequency of 5.8 GHz.

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