적층조건별 물성 예측을 위한 DIGIMAT 활용

박수빈(S.B, Park),우영한(Y.H, Woo),허민도(M.D, Heo),문지훈(J.H, Mun) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

본 연구에서는 구조재로 널리 사용되는 탄소섬유강화플라스틱 복합재 적층조건별 인장, 압축 물성을 가상분석 하였다. 해석 수행에 앞서 필요한 물성 추출을 위해 0 도 인장물성, 압축물성과 45 도 전단물성, 복합재 부피분율, 밀도를 시험·측정하였으며, 해당 값을 바탕으로 가상분석을 진행하였다. 해석을 위한 시편은 Toray 3K Twill, Epoxy(금호피앤비화학, KER9610, KCA9630), 4ply 적층 후 진공백 성형으로 120 도에서 30min 간 경화를 진행하였다. 인장시험은 ASTM D3039, 압축시험은 ASTM D6641, 45 도 전단시험은 ASTM D3518, 부피분율은 ASTM D3171 규격에 따라 시험하였으며, 인장강도 600.85MPa, 인장 modulus 59.23GPa, 압축강도 368.88MPa, 압축modulus 48.56GPa, 전단강도 80.08MPa, 전단modulus 8.01GPa, 부피분율 49.7%의 값을 확인하였다. 해석 시 적층 조건으로는 Trunk Lid Outer에 사용되는 재료이기 때문에 symmetric 한 적층 패턴으로 진행하였으며, [0/45]_s, [0/0/45]_s, [45/0/45]_s, [0], [45]으로 가상분석을 진행하였다. 0 도 인장물성의 경우 시험 값이 해석 값보다 조금 더 높게 나타났으나, 이는 수지 물성 입력 시험 값이 아닌 유사한 수치를 넣어 차이가 있는 것으로 판단되며, 정확한 해석을 위해서는 해당 값을 직접 측정하여 반영해야 한다. 압축의 경우 해석 값과 유사하게 나왔는데 이는 압축의 경우 수지보다 섬유 물성에 크게 작용하기 때문인 것으로 사료되어진다. In this study, the tensile and compressive properties of carbon fiber reinforced plastic composites widely used as structural materials for each lamination condition were virtually analyzed. In order to extract the required physical properties before performing the analysis, the 0 degree tensile property, the compressive property and the 45 degree shear property, the volume fraction of the composite material, and the density were tested and measured, and a virtual analysis was conducted based on the corresponding values. The specimens for analysis were Toray 3K Twill, Epoxy (Kumho P&B Chemical, KER9610, KCA9630), 4ply laminated and then cured at 120 degrees for 30 minutes by vacuum bag forming. The tensile test was ASTM D3039, the compression test was ASTM D6641, the 45 degree shear test was ASTM D3518, the volume fraction was tested according to the ASTM D3171 standard. , Shear strength of 80.08 MPa, shear modulus of 8.01 GPa, and volume fraction of 49.7% were confirmed. In the analysis, the lamination condition was a symmetric lamination pattern because it was a material used for the trunk lid outer, and [0/45]_s, [0/0/45]_s, [45/0/45]_s, [0 ], [45] for virtual analysis. In the case of the 0 degree tensile property, the test value was slightly higher than the analysis value, but it is judged that there is a difference by putting a similar value rather than the resin property input test value. do. In the case of compression, the result was similar to the analysis value, which is believed to be because the compression has a greater effect on fiber properties than resin.

철강산업 용융로의 대기오염물질 배출계수 산정 연구

석광설,방선애,홍지형,이석조,김대곤,이대균,허정숙,이은정 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.4

The purpose of this study is 10 estimate of emission factors of the air pollutants for the melting furnaces for the iron and steel industry. The result of this study is able to obtain the emission factor of particulate matters (PM), sulfur dioxide, nitrogen oxides for melting furnace. The emission factors of each pollutants were as follows: - the emission factor varied between 6.13E-03 ∼ 6.12E-01kg/ton for PM - 1.59E-01 ∼ 2.45E+00kg/ton for S0₂ - 6.82E-02 ∼ 6.88E-01kg/ton for NOx, respectively. Analysis of the differences in the emission factors of ours and U.S. EPA's yielded the following results for the Wilcoxon method: p>0.05. The statistical analysis showed no differences in the our emission factors and U.S. EPA's

Lactococcus lactis BFE920 activates the innate immune system of olive flounder (Paralichthys olivaceus), resulting in protection against Streptococcus iniae infection and enhancing feed efficiency and weight gain in large-scale field studies

Kim, D.,Beck, B.R.,Heo, S.B.,Kim, J.,Kim, H.D.,Lee, S.M.,Kim, Y.,Oh, S.Y.,Lee, K.,Do, H.,Lee, K.,Holzapfel, W.H.,Song, S.K. Academic Press 2013 Fish & shellfish immunology Vol.35 No.5

The protective effect of a food-grade lactic acid bacterium Lactococcus lactis BFE920 against disease of olive flounder (Paralichthys olivaceus) cultivated on a large scale was studied. Initially, antimicrobial activity of L. lactis against several fish pathogens was evaluated in vitro; the probiotic showed strong antibacterial activity against Streptococcus iniae, Streptococcus parauberis and Enterococcus viikkiensis, and moderate activity against Lactococcus garviae. When olive flounders were fed for two weeks with experimental diets containing varying concentrations of L. lactis (1 x 10<SUP>6</SUP>, 5 x 10<SUP>6</SUP>, 2.5 x 10<SUP>7</SUP> and 1.25 x 10<SUP>8</SUP> CFU/g feed), all the experimental feed groups showed 68-77% survival upon challenge with S. iniae. A field-scale feeding trial with L. lactis dietary supplement was conducted in a local fish farm (n = 12,000) for three months, and disease resistance, innate immune parameters and growth performance were evaluated. The average weight gain and feed efficiency were increased up to 6.8% and 8.5%, respectively. At the end of the feeding trial, the olive flounders were challenged with S. iniae. The L. lactis-fed group was protected from S. iniae challenge with a 66% survival rate. This disease protection is due to the flounder's innate immunity activated by the L. lactis administration: increased lysosomal activities and production of IL-12 and IFN-γ. These data clearly indicated that L. lactis BFE920 may be developed as a functional feed additive for protection against diseases, and for enhancement of feed efficiency and weight gain in olive flounder farming.

Rational Design of Low Cost and High Energy Lithium Batteries through Tailored Fluorine-free Electrolyte and Nanostructured S/C Composite

Agostini, M.,Lim, D.-H.,Sadd, M.,Hwang, J.-Y.,Brutti, S.,Heo, J. W.,Ahn, J. H.,Sun, Y. K.,Matic, A. Wiley (John WileySons) 2018 ChemSusChem Vol.11 No.17

<P>We report a new Li-S cell concept based on an optimized F-free catholyte solution and a high loading nanostructured C/S composite cathode. The Li2S8 present in the electrolyte ensures both buffering against active material dissolution and Li+ conduction. The high S loading is obtained by confining elemental S (approximate to 80%) in the pores of a highly ordered mesopores carbon (CMK3). With this concept we demonstrate stabilization of a high energy density and excellent cycling performance over 500 cycles. This Li-S cell has a specific capacity that reaches over 1000 mA hg(-1), with an overall S loading of 3.6 mg cm(-2) and low electrolyte volume (i.e., 10 mu L cm(-2)), resulting in a practical energy density of 365 Wh kg(-1). The Li-S system proposed thus meets the requirements for large scale energy storage systems and is expected to be environmentally friendly and have lower cost compared with the commercial Li-ion battery thanks to the removal of both Co and F from the overall formulation.</P>

Rice serine/threonine kinase 1 is required for the stimulation of OsNug2 GTPase activity

Heo, J.B.,Lee, Y.M.,Yun, H.R.,Im, C.H.,Lee, Y.S.,Yi, Y.B.,Kwon, C.,Lim, J.,Bahk, J.D. G. Fischer 2014 Journal of plant physiology Vol.171 No.17

Several GTPases are required for ribosome biogenesis and assembly. We recently identified rice (Oryza sativa) nuclear/nucleolar GTPase 2 (OsNug2), a YlqF/YawG family GTPase, as having a role in pre-60S ribosomal subunit maturation. To investigate the potential factors involved in regulating OsNug2 function, yeast two-hybrid screens were performed using OsNug2 as bait. Rice serine/threonine kinase 1 (OsSTK1) was identified as a candidate interacting protein. OsSTK1 appeared to interact with OsNug2 both in vitro and in vivo. OsSTK1 was found to have no effect on the GTP-binding activity of OsNug2; however, the presence of recombinant OsSTK1 in OsNug2 assay reaction mixtures increased OsNug2 GTPase activity. A kinase assay showed that OsSTK1 had weak autophosphorylation activity and strongly phosphorylated serine 209 of OsNug2. Using yeast complementation testing, we identified a GAL::OsNug2(S209N) mutation-harboring yeast strain that exhibited a growth-defective phenotype on galactose medium at 39<SUP>o</SUP>C, which was divergent from that of a yeast strain harboring GAL::OsNug2. The intrinsic GTPase activity of OsNug2(S209N), which was found to be similar to that of OsNug2, was not fully enhanced upon weak binding of OsSTK1. Our findings indicate that OsSTK1 functions as a positive regulator of OsNug2 by enhancing OsNug2 GTPase activity. In addition, phosphorylation of OsNug2 serine 209 is essential for its complete function in biological functional pathway.

ASTM D5470 열전도도 측정장치 구축

배강현(G. H. Bae),박준수(J. S. Park),허동영(D. Y. Heo),한승훈(S. H. Han) 한국기계가공학회 2023 한국기계가공학회 춘추계학술대회 논문집 Vol.2023 No.12

Wound healing potential of antibacterial microneedles loaded with green tea extracts

Park, S.Y.,Lee, H.U.,Lee, Y.C.,Kim, G.H.,Park, E.C.,Han, S.H.,Lee, J.G.,Choi, S.,Heo, N.S.,Kim, D.L.,Huh, Y.S.,Lee, J. Elsevier 2014 Materials Science and Engineering C Vol.42 No.-

This study evaluates the utility of an antibacterial microneedle composed of green tea (GT) extract and hyaluronic acid (HA), for the efficient delivery of GT. These microneedles have the potential to be a patient-friendly method for the conventional sustained release of drugs. In this study, a fabrication method using a mold-based technique to produce GT/HA microneedles with a maximum area of ~50mm<SUP>2</SUP> with antibacterial properties was used to manufacture transdermal drug delivery systems. Fourier transform infrared (FTIR) spectrometry was carried out to observe the potential modifications in the microneedles, when incorporated with GT. The degradation rate of GT in GT/HA microneedles was controlled simply by adjusting the HA composition. The effects of different ratios of GT in the HA microneedles were determined by measuring the release properties. In HA microneedles loaded with 70% GT (GT70), a continuous higher release rate was sustained for 72h. The in vitro cytotoxicity assays demonstrated that GT/HA microneedles were not generally cytotoxic to Chinese hamster ovary cells (CHO-K1), human embryonic kidney cells (293T), and mouse muscle cells (C2C12), which were treated for 12 and 24h. Antimicrobial activity of the GT/HA microneedles was demonstrated by ~95% growth reduction of gram negative [Escherichia coli (E. coli), Pseudomonas putida (P. putida), and Salmonella typhimurium (S. typhimurium)] and gram positive bacteria [Staphylococcus aureus (S. Aureus) and Bacillus subtilis (B. subtilis)], with GT70. Furthermore, GT/HA microneedles reduced bacterial growth of infected wound sites in the skin and improved wound healing process of skin in rat model.

Effect of metC mutation on Salmonella Gallinarum virulence and invasiveness in 1-day-old White Leghorn chickens

Shah, D.H.,Shringi, S.,Desai, A.R.,Heo, E.J.,Park, J.H.,Chae, J.S. Elsevier Scientific Pub. Co 2007 Veterinary microbiology Vol.119 No.2

Salmonella enterica serotype Gallinarum (S. Gallinarum) is the causative agent of fowl typhoid (FT) in chickens. FT is a severe systemic disease of chickens causing heavy economic losses to the poultry industry through mortality, reduced egg production and culling of precious breeding stocks. In this study, a metC (encoding cystathionine β lyase) mutant was produced from a virulent strain of S. Gallinarum by Mini-Tn5 insertional inactivation. The mutant was significantly attenuated in virulence for 1-day-old White Leghorn chickens. Inactivation of metC resulted in 10<SUP>4</SUP>-fold increase in the LD<SUB>50</SUB> when compared with the wild type parent. The metC mutant showed an in vivo competitiveness defect in the challenged chickens and significantly lower (P<0.01) bacterial burden in the reticuloendothelial organs when compared with the wild-type parent. These results indicate that metC gene is important for virulence of S. Gallinarum in chickens.

Synthesis and photovoltaic characterization of D/A structure compound based on N-substituted phenothiazine and benzothiadiazole

Yun, D.H.,Yoo, H.S.,Heo, S.W.,Song, H.J.,Moon, D.K.,Woo, J.W.,Park, Y.S. Korean Society of Industrial and Engineering Chemi 2013 Journal of industrial and engineering chemistry Vol.19 No.2

In this study, poly [(N-10'-dodecyl-phenothizin-3,7-ylene)-alt-(2,2'-bithiophen-5-yl)] (P1) and poly [(N-10'-dodecyl-phenothiazin-3,7-ylene)-alt-(5',6'-dioctyloxy-benzothiadiazole-bithiophene)] (P2) were synthesized by Suzuki coupling reaction. Optical and electrochemical characteristics of the synthesized polymers, P1 and P2, were then analyzed, indicating that their wavelength of maximum absorption was 453nm and 533nm, respectively, and their band-gap was 1.93eV and 1.74eV, respectively. The maximum power conversion efficiency (PCE) of organic photovoltaic cells created by using P1 and P2 were 0.74% (P1:PC<SUB>71</SUB>BM=1:4,w/w) and 1.00% (P2:PC<SUB>71</SUB>BM=1:3,w/w), respectively, and the short circuit current density (J<SUB>SC</SUB>), fill factor (FF), and open circuit voltage (V<SUB>OC</SUB>) of the device were 3.5mA/cm<SUP>2</SUP>, 31.8%, and 0.68V, respectively, for P1 and 3.9mA/cm<SUP>2</SUP>, 32.7%, and 0.78V, respectively, for P2.

RraAS1 inhibits the ribonucleolytic activity of RNase ES by interacting with its catalytic domain in Streptomyces coelicolor

Seo, S.,Kim, D.,Song, W.,Heo, J.,Joo, M.,Lim, Y.,Yeom, J. H.,Lee, K. MICROBIOLOGICAL SOCIETY OF KOREA 2017 JOURNAL OF MICROBIOLOGY -SEOUL- Vol. No.

<P>RraA is a protein inhibitor of RNase E, which degrades and processes numerous RNAs in Escherichia coli. Streptomyces coelicolor also contains homologs of RNase E and RraA, RNase ES and RraAS1/RraAS2, respectively. Here, we report that, unlike other RraA homologs, RraAS1 directly interacts with the catalytic domain of RNase ES to exert its inhibitory effect. We further show that rraAS1 gene deletion in S. coelicolor results in a higher growth rate and increased production of actinorhodin and undecylprodigiosin, compared with the wild-type strain, suggesting that RraAS1-mediated regulation of RNase ES activity contributes to modulating the cellular physiology of S. coelicolor.</P>