• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.22-29
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• 2013

The combined structure of both an annular dielectric resonator and a quarter-wave monopole is proposed to generate an omnidirectional radiation pattern over the wideband frequency range. The monopole works at the lower frequency band and excites the cylindrical dielectric resonator along its center point by electrical coupling mechanism. The rectangular shape of the DR is cut to generate the wideband operation of 4.7-18.2 GHz. The geometrical parameter of cylindrical dielectric resonator is 5.8 mm, 11.6 mm and 6.0 mm in inner diameter, outer diameter and height, respectively.

• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.289-296
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• 2010

The effect of organic additives, thiourea (TU), on the copper electroplated layer of large rectangular size was investigated through physical and various electrochemical techniques. It was found that TU had strong adsorption characteristics on the Ni substrate and affected the initial electroplating process by inducing surface reaction instead of mass transfer in the bulk solution. TU additives had its critical micelle concentration at 200 ppm in copper sulphate solution and showed abrupt change in morphological and electrochemical impedance spectroscopic results around this concentration, which could be related with the destruction of adsorption structure of TU-Cu(I) complex formed at the Ni substrate surface. By conducting a commercial electroplating simulation, when TU additives was included at cmc in the plating solution, it acted as a depolarizer for copper electrodeposition and was effective to reduce the unevenness of copper deposits between centre and edge region at high current densities of 10 ASD.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.4
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• pp.11-18
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• 2012

This study is to establish the dwelling principle and architectural characteristics of Powhatan Indian Community in Eastern part of North America. To find a pattern and dwelling principle of town building and housing, I have researched both site survey of Powhatan at Jamestown Settlement in Virginia and a related references of North America Indian. In addition of study, I have tried to understand their life style in 17C, a spatial characteristics of space composition, and a using materials of Yehakin which means Powhatan's house in the exhibition hall of Jamestown Settlement. The results of this paper are as follows: First, the form of Powhatan house is like a longhouse which has two types that are oblong and rectangular house. Usually they had lived in the style of oblong house. Second, there are three patterns to set up the semi-permanent settlement of Powhatan, which are circle-type, street-type, and free-type of village. Third, the fire place of interior space that is most importance element to heat and cook is put it into the center of room, and the other beds and shelves are arranged by the side of wall which is covered of rush matt.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.72-75
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• 2017

In this paper, we design the circular slits in the parch antenna for size reduction and high gain working at 900 MHz. Modifying the rectangular type patch, we decrease the antenna real-estate, leading to antenna miniaturization with added circular slits in itself. The antenna is tuned for under -30 dB return loss by adjusting the number of circular slits and their radii, and its design is performed for the maxim bean pattern of 4 dBi gain. Compared with the antenna without circular slits, the designed antenna shows 20 MHz downward shift of frequency, proving that the size reduction is achieved with this antenna design.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.347-349
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• 2005

This paper presents an efficient algorithm to estimate the maximum load level for heavily loaded power systems with the load-generation variation vector obtained by ELD (Economic Load Dispatch) and/or short term load forecasting while utilizing the elliptic pattern of the P-e curve. It is well known the power flow equation in the rectangular coordinate is fully quadratic. However, the coupling between e and f makes it difficult to take advantage of this quadratic characteristic. In this paper, a simple technique is proposed to reflect the e-f coupling effects on the estimation of maximum loadability with theoretical analysis. An efficient estimation algorithm has been developed with the use of the elliptic properties of the P-e curve. The proposed algorithm is tested on IEEE 14 bus system, New England 39 bus system and IEEE 118 bus system, which shows that the maximum load level can be efficiently estimated with remarkable improvement in accuracy.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.353-360
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• 2008

The LGP with nanometer structures resulted in enhancement of optical efficiency. Its fundamental mechanism is to recycle the polarized light via one round-trip through QWP(Quarter-Wave Plate) but the maximum efficiency to reach with this method is limited up to 2. To get the larger efficiency than this limited one a LGP with nanometer-patterned grating is suggested. For its optimum design the computer simulation is performed and suggests a grating that the spatial frequency between adjacent patterns is 500nm, its height 250nm, duty cycle 50%, and its cross section is rectangular. On the basis of simulation results the LGP with nanometer-patterned grating is fabricated and its optical properties such as angular intensity distribution and CIE color coordinates are characterized. The angles of transmitted light are nearly the same as the results expected from the generalized Snell's law. Thus the Mathematica code, developed in this experiment, will be applied to designing the optimized LGP. The LGP with nanometer-patterened grating shows the enhancement of transmitted intensity distribution up to 4.9 times.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.261-266
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• 2006

In this study, a scaled model chamber was built to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model by visualization equipment with laser apparatus. Four different kinds of measuring area were selected as experimental condition Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system and its software adopting two-frame grey-level cross correlation algorithm. The flow pattern reveals the large scale counter-clockwise forced-vortex rotation at center area.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.421-424
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• 2007

Thermal behavior of $Li_{1-x}CoO_2$ has been investigated employing DSC (Differential Scanning calorimetry) and TGA (Thermogravimetry Analyzer), and the crystal parameters were calculated from XRD (X-ray diffraction).for the commercial rectangular pouch cell(1000 mAh).The cathode materials coated over aluminium foil current collector is made up of a blend consisting of active material $LiCoO_2$(size $20\;{\mu}m$, 94 wt%), conducting material super p black (SPB, 3 wt%) and binder polyvinylidene fluoride (PVDF, 3 wt%). The anode is a mix consisting of carbon (92 wt%) and PVDF(8 wt%) coated over copper foil. The cells for the experiments were first preconditioned by cycling three times and stabilized at OCV=3.0, 3.5, 4.2, 4.35 and 4.5 V. The stabilized cathode material was used for thermal and crystal parameter investigations.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.51-58
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• 2006

The enhancement of antenna near-field measurements is obtained using a general probe compensation equation based on the Lorentz reciprocity theorem and reciprocity notation. The probe compensation is an essential process of the near-field to far-field transformations. Applying the equation proposed in this paper to a planar scanning for a rectangular horn antenna shows that our near-field radiation pattern is similar to that of a far-field and our theory is very simple to use and suitable for most practical applications.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.395-397
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• 2006

Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. The effect of various interlacing nozzle geometries on the interlacing process was studied. The geometries of interlacing nozzles with single or multiple air inlets located across the width of yarn channels are investigated. The basis case is the yarn channel, with a perpendicular main air inlet in the middle. Other cases have main air inlets, slightly inclined double sub air inlets, The yarn channel cross sectional shapes are either semicircular or rectangular shapes. The compressed impinging jet from the main air inlet hole hits the opposing bottom wall of the yarn channel, is divided into two branches, joins with the compressed air coming out from sub air inlet at the bottom and creates two free jets at both ends of the yarn channel. The compressed air movement in the cross-section consists of two opposing directional vortices. The CFD-FASTRAN flow parallel solver was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this pater.