• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.904-911
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• 2011

This paper deals with transmission characteristics of a new dual resonant structure for designing waveguide band-pass filter. The structure which has a pass-band between two adjacent stop-bands in a single body consists of circular ridged aperture and four armed conducting patch. The dual resonant behavior of the structure can be represented by a combination of LC series and parallel resonant circuits. Also these resonant properties can be easily controlled by varying the geometry of the aperture and four armed conducting patch. Actually, the structure is fabricated on the microstrip substrate by use of etching technique so that it is formed an iris type resonator which can be easily put into the transverse plane of the waveguide. We use WR-90 standard waveguide, adapters, and VNA(vector network analyzer) to measure the resonant characteristics of the structure. It is very useful to design and to improve the cutoff skirts characteristics in the waveguide band-pass filter design area.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.430-434
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• 2008

'Morningwhite' is a new sweetpotato variety developed by Mokpo Experiment Station, National Institute of Crop Science (NICS), RDA in 2007, with white flowering. This variety was selected from the cross between "Sinjami" and "Muan 10" in 2004, seedling and line selections were applied in 2005 and 2006. 'Morningwhite' is morning glory type flowers with white color. It has Lobed leaf, green vine and petiole, elliptic storage root, red skin and yellow flesh color of storage root. The average yield of storage root was 14.0 ton/ha. Number of storage roots over 50 gram per plant was 2.5 and the average weight of storage root was 140 gram.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.230-236
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• 1990

To examine the behavior of yellow tail Seriola quinqueradiata and of file fish Navodon modestus to set net, the 1/30 scale model net of the actual set net used in the east coast of Korea was made of netting and set in the indoor experimental tank(700cm W$\times$700cm L$\times$100cm D), of which the water depth was kept 70cm. Total length of yellow tail examined were 37~45cm and file fish were 18~21cm. The fishes were released as groups of 3 to 20 individuals. The number of fish entered into the pound net or the bag net, escaped from the net was counted every minute and accumulated for 10minutes to check the ratio entered and the ratio escaped. The result obtained can be summarized as follows: 1. In case of yellow tail, even though the ratio entered into the pound net was not so high, that into the bag net was comparatively high. Traces of the fish swimming were comparatively smooth and both entering into the pound net and escaping from it was easily done. 2. In case of file fish, even though the ratio entered into the pound net was higher than that of yellow tail, that into the bag net was lower than that into the pound net. Traces of the fish swimming were roundly meandered. Entering into the bag net was not so smoothly done, even though that into the playground was smoothly done. 3. Both yellow tail and file fish, the ratio escaped from the bag net was almost0 and that from the pound net was less than 10%.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.24-28
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• 2002

Effect of pretreatment processing (peeling time, drying temperature, sample type) on the quality of hot air drying peony roots was investigated. Peony roots were peeled for 0, 10, 20, 30, 60, 90 and 120 minute in the peeling machine after water washing. Sample types were whole or cut (thickness of 3mm). Temperatures of hot air drying were 30, 40, 50 and $60^{\circ}C$ The level of water contents in dried sample was $14{\sim}15%$. Drying time was muth reduced as the peeling time, cutting sample types and higher temperature. Contents of paeoniflorin were maintained highest amount (3.48%) in the non-peeling cut sample dried at $30^{\circ}C$ and lowest amount (2.29%) in the 120min-peeling whole one dried at $60^{\circ}C$. Skin color of dried peony roots was heavily discolored in the sample of non-peeling whole type dried at $60^{\circ}C$ and the color was dark brown $({\Delta}E\;was\;46.1)$. When considering shortening of drying time, preservation of active compounds and maintenance of color, the best pretreatment method of drying in peony roots was non-peeling, cut type processing.

• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.247-272
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• 2005

The Philadelphus schrenkii complex including P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, P. tenuifolius, P. pekinensis, P. seoulensis, P. lasiogynus, and P. scaber, is distributed in China, Korea, japan, and far eastern Russia. Their taxonomic delimitations are obscure because quantitative characters, such as presence/absence and density of hair on leaf, petiole, style, disc, calyx-tube, and pedicel, are highly variable with no apparent characteristics that consistently distinguish from each other within the group. Thus, these morphological characters are reexamined using univariate analyses. P. pekinenesis is distinct from other taxa in having glabrous disk, calyx, pedicel, and leaf blade. In addition, the number of flowers in an inflorescence [(5)7-9(11) vs 5-7 in other taxa], smaller calyx tube [2.5-3 mm vs. (2.5)3-4(5.9) in other taxa], and slightly divided styles help distinguish P. pekinenesis from other related taxa in Korea. However, P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, and P. lasiogynus show continuous variation in the pubescence of disk, calyx, pedicel, and leaf blade, and this may reflect a lack of divergence among them. Particular emphases are placed on P. tenuifolius and P. seoulensis, because of the high degree of morphological intergradation with respect to the degree of pubescence in disk, calyx, pedicel, and leaf blade and their inconsistent circumscription across various systematic treatments. P. scaber, distributed in the southern Korea, has often been treated as an independent species having exfoliated branchlets, distinct serrated leaf margin, and recurved styles. However, this current study suggests that P. scaber should be recognized as a form of P. tenuifolius because these distinguishing characters are continuous between P. tenuifolius and P. scaber. In geographical distribution, P. pekinensis is mainly distributed in the southern part of Korea, while P. tenuifoilus and P. schrenkii are commonly found all over the country.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.475-485
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• 2010

This paper proposes a novel concept for a microstrip resonator that can function as a filter and as an antenna at the same time. The proposed structure consists of an outer ring, an open loop-type inner ring, a circular patch, and three ports. The frequencies where the proposed structure works as a filter and as an antenna, respectively, are determined primarily by the radius of the inner ring and the circular patch. The measured results show that, when the microstrip resonator operates as a filtering device, this filter has about 15.1 % bandwidth at the center frequency of 0.63 GHz and a minimum insertion loss of 1.5 dB within passband. There are three transmission zeros at 0.52 GHz, 1.14 GHz, and 2.22 GHz. In the upper stopband, cross coupling - taking place at the stub of the outer ring - and the open loop-type inner ring produce one transmission zero each. The circular patch generates the dual-mode property of the filter and another transmission zero, whose location can be easily adjusted by altering the size of the circular patch. The proposed structure works as an antenna at 2.7 GHz, showing a gain of 3.8 dBi. Compared to a conventional patch antenna, the proposed structure has a similar antenna gain. At the resonant frequencies of the filter and the antenna, high isolation(less than -25 dB) between the filter port and the antenna port can be obtained.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.4
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• pp.25-30
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• 1971

Fabrication and measurements of the magnetically tunable YIG band pass or stop filter at X-band are discussed. Using two YIG spheres located at the region of r-f circularly polarized magnetic field between the strip lines, the pass or stop characteristics of the filter are obtained. In the case of band stop, the output level is typically 25db lower than the input power. Contrarily for the pass band, the pass band level is 22db higher than the stop frequency region. The experimental results are in good agreement with the theoretical values of FMR. Further it is shown that the structure can be used for a directional coupler.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.7
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• pp.525-536
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• 2014

In this paper, GUI program for microspeaker system simulation program was developed and verified through closed box, vent box and 6th order bandpass enclosure system. By using the pseudo loudspeaker model concept, TS parameters and rear volume of microspeaker were identified. Their suitabilities were proved by comparing test results with simulations of electrical impedance and sound pressure response curves for the three box types; closed box, vent box and 6th order bandpass box. Also, MSSP was found to be effective regardless of the microspeaker's shape, either circular or rectangular shape. MSSP can be used for the microspeaker system simulation, and can give a general prediction of such as; sound pressure level curve, electrical impedance, diaphragm velocity and displacement curve according to multiple design parameters; diaphragm mass, compliance, force factor, front and rear volume, front and rear port's diameter and length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.505-513
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• 1996

In this paper the dual-mode bandpass filters with a Chebyshev response are designed and manufactured at Ku-band as well as K-band. Manufactured filters are resonated by two independent orthogonal $TE_{113}$ circular-cavity modes and characterized by 4-pole Chebyshev function. One is operating at a center frequency of 12.5GHz with a bandwidth of 100MHz and the other, a center frequency of 19.25GHz with 120MHz, respectively. The measureed experimental results of a 12.5GHZ dual-mode filter ahve a 1.2dB intertion loss in the passband and 65dB out-of-rejection, and a 19.25GHz filter has a 1.55dB insertion loss and 70dB out-of-rejection. These experimantal results shoults show good agreements with the design specifications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.457-467
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• 2012

In this paper, a miniaturized band-pass filter structure, which comprises the irises of small resonant aperture and L-type irises inverter, is proposed. Ridged circular aperture iris is chosen as an elementary resonator. L-type iris which is placed between two adjacent elementary resonators is newly proposed as impedance inverter in order to reduce longitudinal length of the proposed filter. The fabricated minimized filter has 400 MHz bandwidth at the 10 GHz center frequency and the whole size is reduced to 70 % in length compared to conventional filter.