• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.243-247
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• 2015

The characteristics of the fluid force reduction of a square prism having a small triangular prism at the upstream side was investigated by measuring of lift and drag on the square prism The experimental parameters were the width ratios (H/B=0.2~0.6) of triangular prisms to the prism width and the gap ratios (G/B=0~3) between the square prism and the triangular prism. The drag reduction rate of the square prism was increased and then decreased with G/B in case of the same H/B, and was increased with H/B in case of the same G/B. The maximum drag reduction rate was represented by 78.5% at H/B=0.6 and G/B=1.5. The lift reduction rate of the square prism was hardly not affected by the width and gaps ratios, the average value was about 52.4%.

• Journal of the Korean Mathematical Society
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• v.45 no.5
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• pp.1203-1220
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• 2008

Let V be an arbitrary system of weights on an open connected subset G of ${\mathbb{C}}^N(N{\geq}1)$ and let B (E) be the Banach algebra of all bounded linear operators on a Banach space E. Let $HV_b$ (G, E) and $HV_0$ (G, E) be the weighted locally convex spaces of vector-valued analytic functions. In this paper, we characterize self-analytic mappings ${\phi}:G{\rightarrow}G$ and operator-valued analytic mappings ${\Psi}:G{\rightarrow}B(E)$ which generate weighted composition operators and invertible weighted composition operators on the spaces $HV_b$ (G, E) and $HV_0$ (G, E) for different systems of weights V on G. Also, we obtained compact weighted composition operators on these spaces for some nice classes of weights.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.103-109
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• 2008

In this papaer, a new type of ${\lambda}_g/4$ short stub band pass filter and ${\lambda}_g/2$ open stub band pass filter are purposed. Both are designed using FSCS technique for harmonic suppression. The proposed filters that used FSCS technique and a broadband stop filter is integrated to band pass filter to suppress the harmonics. The BSF are also placed between stubs so that the size is larger than prevent as compared to conventional one. The propose filters have center frequency of 5.8 GHz, bandwidth of 50% and harmonics suppressin is 120% has in bandwith. The measurement results in the case of ${\lambda}_g/4$ short stub filter, insertion loss of 0.5 dB, return loss of 14 dB are achieved and in the case of ${\lambda}_g/2$ open stub filter, loss of 0.8 dB, return loss of 14.4 dB are achieved. The simulation results and the measurement results are almost the same.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.167-173
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• 2008

In this paper, the flexible narrow bandpass filters (BPFs) with ${\lambda}$g/4 short and ${\lambda}$g/2 open stubs by microstrip line on duroid substrate are suggested. These BPFs with narrow bandwidth show flexible bandwidth with variation of the position of the stubs using the Qe (external quality factor) without changing the impedance value at microwave range. On the other hand, by replacing the series quarter-wavelength connecting lines with the equivalent T-shaped line of bandstop filter(BSF), the compact stub bandpass filter with harmonics suppression can be realized. The BPF with ${\lambda}$g/4 short stubs shows the insertion loss of 2.1 dB and the return loss of 18 dB and BPF with ${\lambda}$g/2 open stubs shows the insertion loss of 1.2 dB and the return loss of 21.9 dB at the center frequency of 5.8 GHz and the bandwidth of 10 %.

• Journal of the Korean Mathematical Society
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• v.59 no.4
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• pp.757-774
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• 2022

Let a and b be positive even integers. An even [a, b]-factor of a graph G is a spanning subgraph H such that for every vertex v ∈ V (G), d_H(v) is even and a ≤ dH(v) ≤ b. Let κ(G) be the minimum size of a vertex set S such that G - S is disconnected or one vertex, and let σ₂(G) = min_uv∉E(G) (d(u)+d(v)). In 2005, Matsuda proved an Ore-type condition for an n-vertex graph satisfying certain properties to guarantee the existence of an even [2, b]-factor. In this paper, we prove that for an even positive integer b with b ≥ 6, if G is an n-vertex graph such that n ≥ b + 5, κ(G) ≥ 4, and σ₂(G) ≥ ${\frac{8n}{b+4}}$, then G contains an even [4, b]-factor; each condition on n, κ(G), and σ₂(G) is sharp.

• Journal of Environmental Health Sciences
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• v.35 no.4
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• pp.295-303
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• 2009

A simulated wastewater containing the dye Rhodamine B (RhB) was electrolytically treated using a three-dimensional electrode reactor equipped with granular activated carbon (GAC) as particle electrode. The effect of type of packing material (GAC, ACF, Nonwoven fabric fiber coated with activated carbon), amounts of GAC packing (25-100 g), current (0.5-3 A) and electrolyte concentration (0.5-3 g/l) was evaluated. Experimental results showed that performance for RhB decolorization of the 3 three-dimensional electrodes lie in: GAC > Nonwoven fabric fiber > ACF. When considered RhB decolorization, oxidants concentration and electric power, optimum GAC dosage was 50 g. Generated concentration of 3 oxidants ($ClO_2$, free Cl, $H_2O_2$) was increased with increase of applied current, however optimum current for RhB degradation was 2.5 A. The oxidants concentration was increased with increase of NaCl concentration and optimum NaCl dosage for RhB degradation was 1.5 g/l.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.5
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• pp.439-444
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• 2000

호알칼리성 방선균 Streptomyes sp. B-2를 Glucose Isomerse 생성을 위해 토양에서 분리했다. Glucose Isomerase(G.I)는 high fructose glucose syrup과 fructose의 생산을 위해서 식품 공업에서 아주 중요시되고 있는 효소이다. 호알칼리성 방선균 Streptomyces sp. B-2가 생성하는 glucose isomerase(G.I.)를 정제하였다. G.I.는 (NH$_4$)$_2$So$_4$분획, DEAE-cellulose, Sephadex G-200 chromatography하여 순수 분리 하였다. 순수분리된 G.I.는 electrophoresis에 의해 확인을 했다. SDS-acrylamide gel electrophoresis에 의해 정제된 효소는 single band를 보여주었다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.137-147
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• 2020

This paper proposes printed bow-tie antennas with 3 ~ 5 GHz broadband characteristics were proposed for testing the electromagnetic immunity of automotive electrical components in the 5G frequency band. The antenna get -10 dB bandwidth in the 2.75 ~ 6 GHz frequency band and the broadside radiation pattern with S₁₁ characteristic of -16.2 dB at resonant frequency. In testing electromagnetic immunity in the 5G mobile communication frequency band, the VSWR characteristic remained below 2.1, forming a level of 1 W as proposed by international standards. As a result, it is confirmed that the proposed antenna can be applied to antenna testing for electromagnetic immunity verification in the 5G mobile communication frequency band.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.118-126
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• 2013

The experiment was carried out to analyze the inhibition effect of plant pathogenic fungi and growth promotion activity induced by the bacterial strains isolated from peatmoss. Among the isolated bacterial strains, B10-2, B10-4, B10-5 and B10-6 which showed more than 30% inhibition rate against Botrytis cinerea and Rhizoctonia solani in vitro, were further analyzed in the greenhouse for the growth promotion activity on lettuce (Lactuca sativa), pak-choi (Brassica compestris L. ssp. chinensis) and Chinese cabbage (Brassica campestris L. ssp. pekinensis). The results showed the treatment of B10-4 on lettuce showed the highest growth promotion activity with the leaf area ($169.17cm^2$), fresh weight (leaf: 40.29 g, root: 8.80 g)and dry weight (leaf: 11.24 g, root: 4.17 g), which was about two folds as compared to control. On pak-choi, the growth promotion rate was the highest with the leaf area of $112.87cm^2$, leaf fresh weight of 60.70 g, root fresh weight of 3.37 g, leaf dry weight of 14.34 g, and root dry weight of 1.90 g. As a result of treatment of B10-13 on chinese cabbage, the growth promotion rate was the highest with the leaf area ($293.56cm^2$), fresh weight (leaf: 113.67 g, root: 2.40 g) and dry weight (leaf: 6.03 g, root: 0.53 g). The production of Indole Acetic Acid (IAA) and Indole-3-Butylic Acid (IBA) were also analyzed in these bacterial isolates. The IAA and IBA analyses were carried out in all bacterial isolates each day within the 5 days of incubation period. The highest production of IAA was observed with $112.57{\mu}g/mg$ protein in B10-4 after 3 days of incubation and IBA production was the highest in B10-2 with $58.71{\mu}g/mg$ protein after 2 days of incubation. Also, phosphate solubilizing activity was expressed significantly in B10-13 in comparison to that of other bacterial isolates. Bacterial identification showed that B10-2 was Bacillaceae bacterium and B10-5 was Bacillus cereus, B10-4 and B10-6 were Bacillus sp. and B-13 was Staphylococcus sp. by ITS sequence.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.323-328
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• 1993

Benzo(a)pyrene [B(a)P], one of the polycyclic aromatic hydrocarbons (PAHs) is known as a potent carcinogen. As lipid consumption increases recently, the toxic effect of overheated lipid foods and fats ＆ oils were reported increasingly. In this study, the contents of B(a)p, other PAHs and rancidities of soybean oil were determined, and then the proper heating temperature, time and frequency were recommended, The work was carried out using soybean oil heated at $180\pm$5^{\circ}C$$, $200\pm$5^{\circ}C$$, and $300\pm$5^{\circ}C$$,for 50 hours. Acid Value(AV) and Conjugated Diene Value of samples were determined. The contents of B(a)P and other PAHs contents of all samples were masured by HPLC/UV method. The results obtained were as follows; Each content of PAHs in the fresh soybean oil was: Pyr 1.093, B(a)A 0.986, Ch 1.147, DMBA 1.082, B(e)P 0.664, Per 1.135, B(a)P 0.146, DBA 1.053, 3-MC 0.05 rg/kg. When the soybean oil was heated at $180\pm$5^{\circ}C$$, for 10, 20, 30, and 50 hours, B(a)P conterlts in heated soybean oils were 0.391, 0.692, 0.451, and 0.372 $\mu\textrm{g}$/kg respectively. Acid value of them were 0.26, 0.26, 0.29, and 0.33, and conjugated diene value was 0.67, 0.76, 0.99, and 1.04, respectively. When the soybean oil was heated at $200\pm$5^{\circ}C$$,and $300\pm$5^{\circ}C$$,for 10, 20, 30, and 50 hours, B(a)P coiltents in soybean oil heated at $200\pm$5^{\circ}C$$,were 0.844, 0.512, 0.479 and 0.247 Ig/kg respectively, Acid value 0.22, 0.21, 0.23 and 0.51 and CDNV 0.39, 0.49, 3.27, and 3.89. B(a)P contents in soybean oil heated at $300\pm$5^{\circ}C$$,were 0.466, 0.706, 0.607 and 0.247$\mu\textrm{g}$/kg respectively, Acid value 0.47, 1.57, 3.90, and 6.42 and CDNV 0.65, 2.15, 3.00, and 3.88.