• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.131-136
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• 2011

Synthesis of N-(1H-benzimidazol-2-yl)-6-substituted-1,3-benzothiazol-2-amines and 6-substituted-N-(4,5-dihydro-1H-imidazol-2-yl)-1,3-benzothiazol-2-amines by the reaction of substituted 2-aminobenzothiazoles with carbon disulphide and methyl iodide followed by the reaction with o-phenylene diamine/ethylene diamine are reported. All the synthesized compounds were characterized by elemental analysis, IR spectra and $^1H$ NMR spectral studies. The potent antibacterial and entomological (antifeedant, acaricidal, contact toxicity and stomach toxicity) activities of the synthesized compounds were investigated.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.417-429
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• 2021

Due to fossil fuel depletion and environmental pollution, H2 production from organic waste has received an increased attention. In this study, we present an integrated process for the H2 production from biogas and evaluate the economic feasibility and sustainability via rigorous techno-economic analysis (TEA) and life-cycle assessment (LCA). Through the TEA, we determine the minimum H2 selling price using discounted cash flow analysis and investigate the main cost drivers. The environmental impact of the proposed process is quantified via LCA.

• 한국기계가공학회지
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• 제16권1호
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• pp.90-95
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• 2017

Recently, smaller and lighter products have become of interest in industry applications that increasingly demand thin plate joints of thickness 1.0 mm or less using friction stir welding. In this study, high frequency spindles that run at 3,500-6,500 rpm are introduced for thin friction stir-welded plates. Weldability tests are performed for the butt-joint method of Al5052-H32 alloy of 1.0 mm thickness under 3,500-6,500 rpm spindle revolution with 250-400 mm/min feed speed. An optical microscope was used to analyze the bid structure of the welded zone and stir zone. The tensile-strength and hardness of the welded zone were then measured.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3255-3260
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• 2011

Two novel binuclear metal-organic coordination complexes $[Cd_2(L)_2(bpy)_2(H_2O)_2]{\cdot}6H_2O$ (1), $[Cd_2(L)_2(phen)_2-(H_2O)_2]{\cdot}2H_2O$ (2) (where L = 2-methylquinoline-3,4-dicarboxylate dianion, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by single crystal Xray diffraction, spectral method (IR), elemental analysis and thermal gravimetric analysis (TGA). Both 1 and 2 consist of two Cd(II) atoms bridged by two monoatomic bridging carboxylate groups from two L ligands, and the second carboxylate group of each L is monodentately coordinated to Cd(II), creating a sevenmembered chelating ring. The coordination at each metal nucleus is completed by a water molecule and a chelating bidentate molecule. The 3D structures of the complexes are stabilized by ${\pi}-{\pi}$ stacking interactions and hydrogen-bonds.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.540-543
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• 2000

본연구에서는 Rhodococcus rhodochrous IGTS8 균주를 사용하여 고농도의 유상에서 탈황효율을 높이기 위한 오일 함유비, pH, 영양물질의 영향을 조사하였다. 오일 함유비에 의한 영향은 유상이 30%이하일 경우 그리 크지 않았으며, pH 조절에 의해 50%, 영양물질의 강화에 의해 32%의 탈황효율이 증가했다. 강화배지에서 pH를 조절하며 배양한 결과, 기존의 배양에 비해 136% 탈황효율이 증가했다.

• 대한기계학회논문집A
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• 제33권4호
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• pp.440-446
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• 2009

This paper was designed to fabricate the miniature spur gear with pitch circle of 2.25mm using extrusion process of a mechanically alloyed Al-78wt%Zn powder. The mechanical alloying of the powder particles were performed for ball milled times of 4h, 8h, 16 and 32h by the planetary ball milling. The mechanical properties of these alloyed powders, which were compacted and sintered-cylindrical preforms, were estimated using compression test. The results showed that the alloyed powder with average particle size of $10{\mu}m$ milled for 32h has the highest compressive(fractured) strength(288MPa). Extrusions of the miniature spur gear using the alloyed powder were carried out at different extrusion temperatures. Extrusion temperature of $300^{\circ}C$ provided the spur gear with the highest relative density and Vickers hardness and without any surface defects.

• 한국결정학회지
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• 제6권1호
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• pp.27-35
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• 1995

1-tert-butoxycarbonyl-4-[N-(tert-butoxycarbonyl)-N-(ethoxycarbonylmethyl)amino]-3-phenylsulfonylpyrrolidind [C24H36O8N2S;이하 BEP]의 분자 및 결정구조를 X-선 회절법으로 연구하였다. 이 결정의 분자는 C24H36O8N2S, 삼사정계이고 공간군은 P1이다. 단위세포 길이는 a=11.363(8)Å, b=11.589(6)Å, c=11.013(10)Å,α=95.32(6)°,β=98.64(7)°,γ=79.57(5)°,V=1406.8(18)Å3, t=293K, Z=2이다. 구조해석에 사용한 X-선은 CuKα선(λ=1.5418Å)을 사용하였다. 분자구조는 직접법으로 풀었으며 최소자승법으로 정밀화하였다. 최종 신뢰도 R값은 F≥4 σ(F)인 3621개의 회절반점에 대하여 R=9.78% 이었다.

• 소성∙가공
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• 제32권4호
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• pp.215-220
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• 2023

In this study, the correction process of stress-strain curves obtained from hot compression test is introduced since the barreling induced by friction and adiabatic heat generation induced by plastic work occur under high strain rate. A shear friction factor was quantitatively estimated by measuring the dimension of barreling and temperature rise due to adiabatic heat generation was directly measured during compression test. Thereafter, the stress-strain curves were re-evaluated by introducing several equations to correct the effects of the friction and temperature rise. It was found that adiabatic factor at strain rate of 10/s is in the range of about 0.5 to 0.75 for Nimonic 80A and decreases as the assigned temperature increases.

• 대한기계학회논문집A
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• 제39권7호
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• pp.659-663
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• 2015

본 연구에서는 다른 게이지 체적을 가지는 시편들의 동일한 에너지밀도 하에서의 통전소성 인장 거동을 실험을 통하여 비교하였다. 5052-H32 알루미늄 합금의 통전소성 인장실험의 결과는 시편의 게이지 길이나 폭 혹은 체적에 상관없이 동일한 에너지밀도가 가해질 때 거의 유사한 통전소성 특성을 보여준다. 특히 통전소성 인장시험의 전형적인 현상인 stress-drop 의 크기를 비교할 때, 소재의 통전소성이 개별적인 전류밀도와 통전시간이 아닌 에너지밀도에 의해서 영향을 받는다는 것을 확인할 수 있다. 본 논문의 결과는 통전소성 현상을 응용한 제조공정의 개발 시 공정설계변수들 중 전류밀도와 통전시간 두 가지를 에너지밀도 하나로 줄일 수 있다는 것을 의미하며 이는 향 후 다양한 통전소성 기반 제조기술의 개발에 이바지 할 것으로 예상된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권2호
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• pp.155-160
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• 2014

The purpose of this study was to estimate genetic parameters of ultrasound measurements for longissimus dorsi muscle area (LMA), backfat thickness (BFT), and marbling score (MS) in Hanwoo cows (N = 3,062) at the ages between 18 and 42 months. Data were collected from 100 Hanwoo breeding farms in Gyeongbuk province, Korea, in 2007 and 2008. The cows were classified into four different age groups, i.e. 18 to 22 months (the first pregnancy period), 23 to 27 (the first parturition), 28 to 32 (the second pregnancy), and 33 to 42 (the second parturition), respectively. For each age group, a multi-trait animal model was used to estimate variance components and heritabilities of the three traits. The averages of LMA, BFT, and MS measurements across the cows of all age groups were 50.1 $cm^2$, 4.62 mm, and 3.04, respectively and heritability estimates were 0.09, 0.10, and 0.08 for the respective traits. However, when the data were analyzed in different age groups, heritability estimates of LMA and BFT were 0.24 and 0.47, respectively, for the cows of 18 to 22 months of age, and 0.21 for MS in the 28 to 32 months old cows. When the cows of all age groups were used, the estimates of genetic (phenotypic) correlations were 0.43 (0.35), -0.06 (0.34) and 0.21 (0.32) between LMA and BFT, LMA and MS, and BFT and MS, respectively. However, in the cow age group between 28 and 32 (18 and 22) months, the estimates of genetic (phenotypic) correlations were 0.05 (0.29), -0.15 (0.24) and 0.38 (0.24), for the respective pairs of traits. These results suggest that genetic, environmental, and phenotypic variations differ depending on cow age, such that care must be taken when ultrasound measurements are applied to selection of cows for meat quality.