• E2M - 전기 전자와 첨단 소재
• /
• 제8권6호
• /
• pp.721-726
• /
• 1995

In this paper, reduction characteristics of NOx gas produced from diesel engine combustion is studied by using pulse corona discharge. Nox concentration of 1900ppm (NO 1870, NO$\sub$2/ 30 ppm, N$\sub$2/ balance gas) was controlled in a fixed quantity of 280ppm, using a flow meter. Reactors are composed of cylinder type. NOx reduction rate is investigated with discharge electrode diameter[0.5,1,3,4.phi.], reactor length [130,300mm], reactor materials[Copper, Poly Vinyl Chloride] and Input voltage[DC, AC, DC Pulse square voltage]. In the result, NOx reduction rate is the best of all in copper reactor, small electrode diameter[0.5.phi.], DC pulse voltage and long reactor[300mm]. Then Teduction rate of NOx is about 93%.

• Transactions on Electrical and Electronic Materials
• /
• 제1권4호
• /
• pp.16-19
• /
• 2000

Power transistors to be used in Power Integrated Circuits(PIC) are required to have low on resistance, fast switching speed, and high breakdown voltage. The lateral IGBTs(LIGBTs)are promising power devices for high voltage PIC applications, because of its superior device characteristics. In this paper, dual cathode LIGBT(DCIGBT) for high voltage is presented. We have verified the effectiveness of high blocking voltage in the new device by using two dimensional devices simulator. We have analyzed the forward blocking characteristics , the latch up performance and turn off characteristics of the proposed structure. Specially, we have focused forward blocking of LIGBT. The forward blocking voltage of conventional LIGBT and the proposed LIGBT are 120V and 165V, respectively. . The forward blocking characteristics of the proposed LIGBT is better than that of the conventional LIGBT. This forward blocking comparison exhibits a 1.5 times improvement in the proposed LIGBT.

• Transactions on Electrical and Electronic Materials
• /
• 제12권1호
• /
• pp.1-6
• /
• 2011

This paper summarized concept, manufacture and results of the micro-tubular solid oxide fuel cells (SOFCs). The cells were fabricated by co-sintering of extruded micro-tubular anode support and electrolyte coating layer, and then additional cathode coating. The cells showed quick voltage rising within 1 minute, and the electrochemical performances were closely related to the balance of fuel utilization and performance loss. And a thermal-fluid simulation model was also reported in combination with the electrochemical evaluation results on the GDC-based micro-tubular SOFCs.

• 대한산업공학회지
• /
• 제18권1호
• /
• pp.11-24
• /
• 1992

The performance of Storage assignment policies is traditionally evaluated with the storage capacity of and AS/RS taken as given. However, the storage capacity is closely related to the inventory model used in real situations. This paper presents a model of evaluating the performance of three storage policies(random storage, class-based storage, and full turnover-based storage) considering production lot-sizing simultaneously with storage assignment of inventory items. The objective of the model is to achieve a balance of warehouse throughput and space requirements such that a total of material handling cost, production ordering cost, and inventory holding cost is minimized. The effects of the parameters involved in the model are investigated on the performance of each storage policy through example problems.

• 한국유기농업학회지
• /
• 제19권spc호
• /
• pp.178-181
• /
• 2011

The test was carried out at a test field at the Wanju Eco-Farming Complex from 2009 to 2010 to figure out the proper application of fertilizers when growing rice at the Eco-Farming Complex. The result showed that when compared to the basal application of compost as fertilizer, applying supplementary compost after natural re-seeding of chinese milk vetch (CMV) helped balance soil nutrition and maintained rice yields.

• Coupled systems mechanics
• /
• 제3권1호
• /
• pp.53-71
• /
• 2014

Accurate prognoses of the durability of concrete structures require a detailed description of the continuously running aging processes and a consideration of the complete load history. Therefore, in the framework of continuous porous media mechanics a model is developed, which allows a detailed analysis of the most important aging processes of concrete as well as a flexible coupling of different processes. An overview of the prediction model and the balance equations is given. The material dependent model equations, the consequences of coupling different processes and the solution scheme are discussed. In two case studies the aging of concrete due to hydration and chloride penetration are presented, which illustrate the capabilities and the characteristics of the developed model.

• Coupled systems mechanics
• /
• 제12권1호
• /
• pp.69-81
• /
• 2023

This paper considers a delamination analysis of a statically undetermined inhomogeneous beam structure of rectangular section with viscoelastic behavior under torsion. The beam is built in at its two ends. The beam has two longitudinal inhomogeneous layers with a delamination crack between them. A notch is made in the upper crack arm. The external torsion moment applied on the beam is a function of time. Under these conditions, the beam has one degree of indeterminacy. In order to derive the strain energy release rate, first, the static indeterminacy is resolved. Then the strain energy release rate is obtained by analyzing the balance of the energy with considering the viscoelastic behavior. The strain energy release rate is found also by analyzing the compliance of the beam for checkup. Solution of the strain energy release rate in a beam without a notch in the upper crack arm is derived too. In this case, the beam has two degrees of static indeterminacy (the torsion moment in the upper crack arm is treated as an additional internal redundant unknown). A parametric investigation of the strain energy release rate is carried-out.

• Advances in nano research
• /
• 제15권2호
• /
• pp.141-153
• /
• 2023

The main objective of this paper is to develop the finite element study on the nonlinear free vibration of functionally graded nanocomposite spherical shells reinforced with graphene platelets under the first-order shear deformation shell theory and von Kármán nonlinear kinematic relations. The governing equations are presented by introducing the full asymmetric nonlinear strain-displacement relations followed by the constitutive relations and energy functional. The extended Halpin-Tsai model is utilized to specify the overall Young's modulus of the nanocomposite. Then, the finite element formulation is derived and the quadrilateral 8-node shell element is implemented for finite element discretization. The nonlinear sets of dynamic equations are solved by the use of the harmonic balance technique and iterative method to find the nonlinear frequency response. Several numerical examples are represented to highlight the impact of involved factors on the large-amplitude vibration responses of nanocomposite spherical shells. One of the main findings is that for some geometrical and material parameters, the fundamental vibrational mode shape is asymmetric and the axisymmetric formulation cannot be appropriately employed to model the nonlinear dynamic behavior of nanocomposite spherical shells.

• 펄프종이기술
• /
• 제48권1호
• /
• pp.100-110
• /
• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• 한국식품과학회지
• /
• 제30권5호
• /
• pp.1114-1119
• /
• 1998

지방질층(${\omega}3$계 고도불포화 지방산을 함유한 정제어유)과 수분층(고분자 물질의 분산 호화액)이 3:2(w:w)의 비율로 혼합되고 유화제가 0.50%(w/w)의 농도로 첨가된 O/W형 유화계내에서 첨가된 유화제와 고분자물질의 종류 및 조성이 유화안정성에 미치는 영향을 검토하였다. HLB값이 11.0 이상 또는 2.8 이하인 단일종류의 유화제가 첨가된 실험구가 99.0 이상의 높은 ESI값을 갖는 안정한 유화계를 형성하였으며, HLB값이 $3.4{\sim}8.6$ 범위의 단일 종류 유화제를 첨가한 경우는 40.0 이하의 낮은 ESI값을 갖는 불안정한 유화계를 형성하였고, 특히 HLB값이 0.6인 유화제 PGPR(polyglycerol polyricinoleate)을 첨가한 경우는 100.0의 높은 ESI값을 나타낼 뿐만 아니라 안정한 유화계를 형성하는 양상을 나타내었다. 또한, PGPR과 PSML(polyoxyethylene sorbitan monolaurate)을 함께 0.50%(w/w)의 농도로 첨가하면 단일 종류의 유화제를 첨가한 경우에 비하여 ESI값이 모두 높은 유화계를 형성하였으며, 유화제의 최적 조성은 PGPR이 0.25%(w/w), PSML이 0.25%(w/w)이었다. 피복물질로서는 waxy corn starch와 agar를 각각 0.25%(w/v) 및 0.50%(w/v)의 농도로 고르게 분산 액화시킨 수분층을 사용한 유화계에서 최대의 ESI값을 갖는 것으로 판명되었다.