• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.68-73
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• 2010

In this paper, a compact Ultra-Wideband band-pass filter with notched band at 5.8GHz by using LC resonator is proposed. The structure of the proposed band-pass filter is very simple, and the DGS(Defected Ground Structure) is used to get the low-pass filter characteristics and the LC resonator is used to get the notched filter. The proposed band-pass filter can be much smaller than a cascaded filter type. The LC resonator is designed with a radial stub and small stub. As a result of measurement, the insertion loss is less than 0.5dB throughout the pass-band of 2.21GHz~10.92GHz, the return loss is more than 16dB and the maximum variation of group delay is 0.29ns and a notched band is 5.2GHz~6.2GHz.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.234-238
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• 1989

The crystal structure of partially $Ag^+$-exchanged zeolite A, $Ag_{3.2}Na_{8.8}$-A, vacuum dehydrated at $360^{\circ}C$ and then exposed to 0.1 torr of cesium vapor for 12 hours at $250^{\circ}C$ has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m (a = 12.262(2)${\AA})\;at\;21(1)^{\circ}C$. The structure was refined to the final error indexes $R_1=0.068\;and\;R_2=0.072$ by using 338 reflections for which $I_o\;>\;3{\sigma}(I_o)$ and the composition of unit cell is $Ag_{3.2}Cs_{8.8}-A.\;3\;Cs^+$ ions lie on the centers of the 8-rings at sites of D4h symmetry. Two crystallographycally different 6-ring $Cs^+$ ions were found: 1.5 $Cs^+$ ions at Cs(2) are located inside of sodalite cavity and 4.3 $Cs^+$ ions at Cs(3) are located in the large cavity. The fractional occupancies observed at Cs(2) and Cs(3) indicate that the existence of at least three types of unit cells with regard to the 6-ring $Cs^+$ ions. For example, 50% of unit cells may have two $Cs^+$ ions at Cs(2) and 4 $Cs^+$ ions at Cs(3). 30% of unit cells may have one Cs+ ion at Cs(2) and 5 $Cs^+$ ions at Cs(3). The remaining 20% would have one $Cs^+$ ion at Cs(2) and 4 $Cs^+$ ions at Cs(3). On threefold axes of the unit cell two non-equivalent Ag atom positions are found in the large cavity, each containing 0.64 and 1.92 Ag atoms, respectively. A crystallographic analysis may be interpreted to indicate that 0.64 $(Ag_5)^+$ clusters are present in each large cavity. This cluster may be viewed as a tetrasilver molecule $(Ag_4)^0$(bond length, 2.84${\AA}$) stabilized by the coordination of one $Ag^+$ ion.

• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.145-150
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• 1999

Gd1-xSrxMnO3(0$\leq$X$\leq$0.6) as the cathode for solid oxide fuel cell was synthesized by citrate process and studied for its crystal structure, electrical conductivity, thermal expansion coefficient (TEC), and investigated reactivity with 8 mol% yttria stabilized zirconia(8YSZ) or Ce0.8Gd0.2O1.9 (CGO). The crystal structure of Gd1-xSrxMnO3 changed from orthorhombic (0$\leq$X$\leq$0.3) through cubic (0.4$\leq$X$\leq$0.5) to tetragonal structure (X=0.6). When Sr contents was increased, the electrical conductivity of Gd1-xSrxMnO3 was inthose of La1-xSrxMnO3, 8YSZ and CGO if Sr content was above 30mol%. TEC of Gd1-xSrxMnO3 was increased with Sr content. After heat treatment at 1300$^{\circ}C$ for 48 hours, reaction product of Gd1-xSrxMnO3 and 8YSZ was SrZrO3. However CGO had no reaction product with Gd1-xSrxMnO3.

• Structural Engineering and Mechanics
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• v.8 no.6
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• pp.547-560
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• 1999

In this paper an asymptotic iteration method is adopted to analyze non-linear free vibration of reticulated circular plates composed of beam members placed in two orthogonal directions. For the resulting linear ordinary differential equations in the process of iteration, the power series with rapid convergence has been applied to obtain an analytical solution for non-linear characteristic relation between the amplitude and frequency of the structure. Numerical examples are given, and the phenomena indicating hardening of such structures have been presented for the (immovable or movable) simply-supported and clamped circular plates.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1405-1406
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• 2009

• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.695-699
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• 1992

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.338-343
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• 1995

The electronic structure of photoskinsensitizing 8-azapsoralen and 4,4',5'-trimethyl-8-azapsoralen has been investigated by the semiempirical (PM3-CI-UHF, etc) methods. The formation of molecular complexes between ground thymine and excited azapsoralen is discussed in terms of charge transfer interaction. The results indicated that the most probable orientation through C4-cycloaddition of 3,4-double bond of azapsoralen and 5,6-double bond of thymine bases, expecially photoadducts were inferred to be a trans-anti azapsoralen(3,4) < > Thymine(5,6) and trans-anti 4,4',5'-trimethyl-8-azapsoralen (3,4) < > Thymine(5,6).

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.945-952
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• 2003

With the rapid growth of the B2B electronic commerce, digital catalogs for expressing product information effectively and exchanging it easily between companies become increasingly important. In this paper, we refer a product expression model to effectively integrate product information, and implement the model using XDK(XML Development Kit), which is given by Oracle 8i. We will first derive an XML DTD reflecting the model. We will then develop a system that stores and retrieves product information on/from Oracle 8i databases, which is written in XML, complying the XML DTD structure. Finally, We will give an experiment on the system.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.3
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• pp.17-24
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• 2013

This study examined and investigated architectural characteristics such as the use of buildings, the number of layers, and structure, and roof landscape characteristics such as roof types, materials, and color in rural villages which were located on the street on the assumption that the landscape of rural villages should be managed by considering visual aspects. The results were as follows. The commonest frequency was found in 'residence'(2/3) for the use of buildings and 'masonry structure'(2/3) for the structure. 'Wood structure' and 'light gauge steel structure(prefabricated structure)' were also commonly found. The results suggest that although many rural houses have partially improved by agricultural and fishery development projects and garden suburbs has been increased by city residents' desire for rural life, there have been still many old houses. Frequently used roof types were a gambrel roof and a hipped roof. Roof materials were mixed in several materials such as tiles, slate, panels, color steel plate, reinforced concrete, and asphalt shingles. Roof color was also mixed in several colors such as reddish N7 and N0.5 of Neutral color, 10R3/6 and 10R3/10 of R color, 7.5B4/10 and 7.5B7/8 of B color and 5G8/6 of G color. The result suggests that roof color impedes the landscape of rural villages on the street. Based on the results, some roofs of rural villages were improved by the support of the government or the local governments but there are still many old roofs. The mixture of improved roofs and old roofs mainly contributed to impeding the landscape of rural villages and it was probably caused by the lack of systematic landscape plans by individual improvement of buildings. Therefore, it is necessary to devise systematic landscape plans in consideration of local identity and neighboring environment. In particular, the guideline for roof color influencing a street landscape should be established.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1182-1190
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• 2001

In this paper, microstrip photonic bandgap (PBG) structure with special perforation patterns etched on the line itself is analyzed and optimized in shape, then used for harmonic tuning of power amplifier. This PBG has an advantage in being fabricated and grounded. The dimension of unit lattice is enlarged vertically, but its input and output line maintain 50 Ω using tapered line. This modification from original structure can lessen possible error in etching PCB. The analysis and design of PBG structure are acquired from using EM simulation. The measured insertion loss of the final structure is 0.3 ∼0.4 dB, and its bandwidth of stopband is 6∼7 GHz. Measured results of improved characteristics by using PBG structure at the output of the power amplifier are 0.72∼0.99 dB in output power, 1.14∼7.8 % in PAE, and 1 dBc in the third IMD.