• 한국주조공학회지
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• 제2권3호
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• pp.16-24
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• 1982

For the purpose of development of domestic carburizer, when the basicity of ash in carburizer was changed from $Na_2O/Al_2O_3+SiO_2$ ; 0.06 to $Na_2O/Al_2O_3+SiO_2$ ; 0,196wt%, using $Na_2O$ as flux for domestic graphite resource (Bong Myung armorphous graphite), carburizing efficiency was improved as basicity increased, optimum basicity value was $Na_2O/Al_2O_3+SiO_2$ ; 0.151. This means that $Na_2O$ contributed to lower viscosity of slag and raise occurence probability of specific reaction surface between molten iron and carburizer. The experiment of effect of general characteristics offecting carburizing ability of this carburizer was performed, the result is that 10/30 mesh was optimum size of the carburizer and as carbon equivalent of molten iron was higher, carburizing ratio was lowered, but when si concentration was below 1.8% in general cast iron melting region, recovery showed 75-85%. As agitation rate of molten iron and temperature interval were higher, Carburizing ratio was increased and showed max, 94%. Desulfurizing phenomena of molten iron by $Na_2O$ in carburizer didn't appear.

• 자원ㆍ환경경제연구
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• 제10권4호
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• pp.547-567
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• 2001

This paper analyzed what kind of institutional scheme for domestic policy instruments to reduce GHG emissions are desirable for Korea in complying with the international efforts to mitigate climate change, by focusing on independent abatement(equivalent to the imposition of carbon tax) and domestic emission trading. It also examined the economic and environmental implications of recycling the government revenue created from implementation of those policies. By utilizing a dynamic CGE model, this study shows that the economic cost under independent abatement is projected to be higher than that under emission trading. It is because under independent abatement scheme each emitter in economy must meet its emission target regardless of the abatement cost. On the other hand, emission trading allows emitters to reduce the marginal cost of abatement through trading of emission permits. In designing future domestic policies and measure to address the climate change problem in Korea, therefore, this study proposes the introduction of domestic emission trading scheme as the main domestic policy instrument for GHG emission abatement. In terms of double dividend, in addition, this study shows that both independent abatement and emission trading schemes under various assumption on the revenue recycling may not generate the double dividend in Korea.

• Mass Spectrometry Letters
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• 제2권2호
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• pp.41-44
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• 2011

Molecular compositions of two types of heavy oil were studied using positive atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Vacuum gas oil (VGO) was generated from vacuum distillation of atmospheric residual oil (AR), and slurry oil (SLO) was generated from catalytic cracking of AR. These heavy oils have similar boiling point ranges in the range of 210-$650^{\circ}C$, but they showed different mass ranges and double-bond equivalent (DBE) distributions. Using DBE and carbon number distributions, aromatic ring distributions, and the extent of alkyl side chains were estimated. In addition to the main aromatic hydrocarbon compounds, those containing sulfur, nitrogen, and oxygen heteroatoms were identified using simple sample preparation and ultra-high mass resolution FT-ICR MS analysis. VGO is primarily composed of mono- and di-aromatic hydrocarbons as well as sulfur-containing hydrocarbons, whereas SLO contained mainly polyaromatic hydrocarbons and sulfur-containing hydrocarbons. Both heavy oils contain polyaromatic nitrogen components. SLO inludes shorter aromatic alkyl side chains than VGO. This study demonstrates that APPI FT-ICR MS is useful for molecular composition characterization of petroleum heavy oils obtained from different refining processes.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.79-81
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• 2005

Bridges constructed recently are preferred to have long spans and simple structure details considering not only the function as bridge but scenic beauty, maintenance, construction term and life cycle cost, etc. Therefore, they require high performance steels like extra-thick plate steels and TMCP steels. A TMCP steel produced by themo-mechanical control process is now spot lighted due to the weldability for less carbon equivalent. It improved at strength and toughness in microstructure. Recently, the SM570-TMC steel which is a high strength TMCP steel whose tensile strength is 600MPa has been developed and applied to steel structures. But, for the application of this steel to steel structures, it is necessary to elucidate not only the material characteristics but also the mechanical characteristic of welded joints. In this study, the characteristics of residual stresses in welded joints of SM570-TMC steel were studied through the three-dimensional thermal elastic-plastic analyses on the basis of mechanical properties at high temperatures obtained from the elevated temperature tensile test.

• 미생물학회지
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• 제22권3호
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• pp.167-173
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• 1984

The cellabiase (${\beta}$-glucosidase) gene in a Cellulomonas sp. CS1-1 was cloned into E. coli HB101 using the vector plasmid pBR322, and the expression of the gene in E. coli studied. The chromosomal DNA of the cellulomonas was digested by seveal restriction enzymes, each of which has only one cleaving site in plasmid pBR322. The recombinant plasmid, pSB2, created with Sal I frament, was expressed for the cellobiase gene in E. coli. The recombiant plasmid was estimated to contain 6.4 Kb foreign DNA at the Sal I site of plasmid pBR322 and the inserted DNA was mapped by single and double digestion with several enzymes. E. coli HB101(pSB2) has slowly grown in a mineral liquid medium containing cellobiose as a sole carbon source. The cellobiase activity in the transformed E. coli was 132 units per liter, which is equivalent to one twenty fifth of that in doner strain Cellulomonas sp. CS1-1. The transforned cell with plasmid containing cellulase gene grow well in the LB mediuns. The synthesis of cellobiase in the strain, E. coli HB101 (pSB2), was inhibited by glucose and at high concentration of cellobiose, and induced by cellobiose at low concentration.

• 공업화학
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• 제18권1호
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• pp.1-9
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• 2007

천연가스는 가솔린에 비하여 에너지 밀도가 매우 낮아 천연가스 차량의 경우 약 24.8 MPa로 압축된 압축천연가스(CNG)를 이용하기 때문에 고압을 얻기 위하여 다단계 압축이 요구될 뿐 아니라 안정성에 문제가 많다. 이런 이유로 비교적 낮은 압력에서 저장할 수 있는 흡착천연가스에 관심을 갖게 되었다. 천연가스의 저장에 용이한 매질을 개발하여 3.5 MPa에서 CNG와 에너지 밀도가 유사하고, 같은 용적의 가솔린에 비하여 1/4 수준의 운전거리를 확보하는 것이 현재의 목표이다. 본 총설에서는 흡착천연가스(ANG) 저장을 위한 탄소매질의 개발현황, 매질의 특성 및 실용화를 위하여 진행되고 있는 내용을 간략하게 소개하고 몇 가지 필요한 제언을 한다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.276-278
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• 2005

Bridge constructed recently is preferred to have a long span and a simple structure detail considering not only functions as bridge but scenic beauty, maintenance, construction term and life cycle cost, etc. Therefore, it demands a high quality steel like a thick plate steel and a high performance steel. A TMCP steel produced by theme-mechanical control process is now spotlighted due to the weldability for less carbon equivalent. It improved at strength and toughness in microstructure. Resently the SM570-TMC steel, a high strength TMCP steel whose tensile strength is 600MPa, is developed and applied to steel structures. But, for the application of this steel to steel structures, it is necessary to elucidate not only the material characteristics but also the mechanical characteristic of welded joint. In this paper, we investigated the characteristics of residual stresses generated by welding of SM570-TMC steels through an experimental study

• Geomechanics and Engineering
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• 제12권2호
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• pp.327-346
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• 2017

Laminated plates have many applications in different industrials. Buckling analysis of these structures with the nano-scale reinforcement has not investigated yet. However, buckling analysis of embedded laminated plates with nanocomposite layers is studied in this paper. Considering the single-walled carbon nanotubes (SWCNTs) as reinforcement of layers, SWCNTs agglomeration effects and nonlinear analysis using numerical method are the main contributions of this paper. Mori-Tanaka model is applied for obtaining the equivalent material properties of structure and considering agglomeration effects. The elastic medium is simulated by spring and shear constants. Based on first order shear deformation theory (FSDT), the governing equations are derived based on energy method and Hamilton's principle. Differential quadrature method (DQM) is used for calculating the buckling load of system. The effects of different parameters such as the volume percent of SWCNTs, SWCNTs agglomeration, number of layers, orientation angle of layers, elastic medium, boundary conditions and axial mode number of plate on the buckling of the structure are shown. Results indicate that increasing volume percent of SWCNTs increases the buckling load of the plate. Furthermore, considering agglomeration effects decreases the buckling load of system. In addition, it is found that the present results have good agreement with other works.

• Steel and Composite Structures
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• 제24권4호
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• pp.499-512
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• 2017

This paper deals with nonlinear dynamic stability of embedded piezoelectric nano-composite separators conveying pulsating fluid. For presenting a realistic model, the material properties of structure are assumed viscoelastic based on Kelvin-Voigt model. The separator is reinforced with single-walled carbon nanotubes (SWCNTs) which the equivalent material properties are obtained by mixture rule. The separator is surrounded by elastic medium modeled by nonlinear orthotropic visco Pasternak foundation. The separator is subjected to 3D electric and 2D magnetic fields. For mathematical modeling of structure, three theories of classical shell theory (CST), first order shear deformation theory (FSDT) and sinusoidal shear deformation theory (SSDT) are applied. The differential quadrature method (DQM) in conjunction with Bolotin method is employed for calculating the dynamic instability region (DIR). The detailed parametric study is conducted, focusing on the combined effects of the external voltage, magnetic field, visco-Pasternak foundation, structural damping and volume percent of SWCNTs on the dynamic instability of structure. The numerical results are validated with other published works as well as comparing results obtained by three theories. Numerical results indicate that the magnetic and electric fields as well as SWCNTs as reinforcer are very important in dynamic instability analysis of structure.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1851-1853
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• 2006

We herein report a new analytical application of XPS to the identification of organic molecules in room temperature ionic liquid for the first time. An organic compound, propargylamine (1), produced in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]), which is one of the room temperature ionic liquids (RTILs), via $A^3$ coupling reaction, is characterized by means of x-ray photoelectron spectroscopy (XPS) rather than using conventional organic compound analysis techniques. There are four non-equivalent carbons in RTILs and 1 each. The ratios of normalized integrated areas of the deconvoluted binding energy of core electron of carbon (C1s) peaks are well matched to the number of carbons in those compounds. The binding energies of C1s of the featured carbons in 1, C4 (sp carbons in acetylene group) and C5 ($sp^2$ carbons in benzene ring), are assigned 286.2 and 285.4 eV, respectively. These results will be able to provide an important tool and a new strategy for the analysis of organic molecules