• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.302-303
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• 2006

The response surface modeling of the pretilt angle control using ion-beam (IB) alignment on nitrogen doped diamond-like carbon (NDLC) thin film layer is investigated. The response surface model is used to analyze the variation of the pretilt angle under various process conditions IB exposure angle and IB exposure time are considered as Input factors. The analysis of variance technique is used to analyze the statistical significance, and effect plots are also investigated to examine the relationships betweenthe process parameters and the response. The model can allow us to reliably predict the pretilt angle with respect to the varying process conditions.

• 한국환경보건학회지
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• 제21권4호
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• pp.24-31
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• 1995

Gas sensing element, $\alpha-Fe_2O_3$ was synthesized by dehydration, reduction, and oxidation of $\alpha-FeOOH$, which was synthesized with $FeSO_4\cdot 7H_2O$ and NaOH. They were produced as a bulk-type, a thick film-type. Then, their responses and mechanisms of response to the gas of carbon monoxide were studied. The qualities of gas sefising elements are decided by the structure and the relative surface area. In the process of $\alpha-FeOOH$ synthesis, the effects of reaction conditions as the equivalent ratio, on the structure and the relative surface area of gas sensing element were observed. The changes of the structure were measured with XRD, SEM,TG-DTA and BET. The resistance changes of the synthesized gas sensor in the air were measured. The response ratio were also measured for the changes of working temperature and gas concentration. As a result of analysis with XRD, it was confirmed that the the best conditions for the synthesis of $\alpha-FeOOH$ were equivalent ratio 0.65. The thick film-type element of $\gamma-Fe_2O_3$ responded more quickly than the bulk-type did. The structure and the relative surface area of the $\rho-FeOOH$ were confirmed as the important factors deciding gas response charcteristics.

• 한국생산제조학회지
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• 제21권5호
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• pp.797-804
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• 2012

Magnesium has a long tradition of use as a lightweight material in the field of automotive industry. This paper presents the design optimization process of Mg armrest frame to minimize its weight by replacing the steel frame. formerly, the analysis of steel armrest frame was peformed to determine the design specifications for Mg armrest frame. The initial design of Mg armrest frame was carried out by topological optimization technique. After six types of design variables and four types of response variables were defined, DOE(Design of Experiment) and RSM (Response Surface Method) were applied in order to measure sensitivity of design variables and realize optimization through regression model. After design optimization, the weight of the optimized Mg armrest frame was reduced by about 3% compared to the initial design of the Mg frame and was decreased by 41.7% in comparison with that of the steel frame. Some prototypical armrest frames were also made by die casting process and tested. The results were satisfying for its design specifications.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.182-194
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• 2017

The optimum alkali pretreatment parameters (reaction time, reaction temperature and potassium hydroxide concentration) for facilitate the conversion into fermentable sugar (glucose) from steam exploded (severity log Ro 2.45) barley husk were determined using Response Surface Methodology (RSM) based on a factorial Central Composite Design (CCD). The prediction of the response was carried out by a second-order polynomial model and regression analysis revealed that more than 88% of the variation can be explained by the models. The optimum conditions for maximum cellulose content were determined to be 201 min reaction time, $124^{\circ}C$ reaction temperature and 0.9% potassium hydroxide concentration. This data shows that the actual value obtained was similar to the predicted value calculated from the model. The pretreated barley husk using acid hydrolysis resulted in a glucose conversion of 94.6%. This research of steam explosion and alkali pretreatment was a promising method to improve cellulose-rich residue for lignocellulosic biomass.

• Journal of Welding and Joining
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• 제19권2호
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• pp.228-234
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• 2001

A methodology is developed and used to evaluate the response sensitivity of the thermal systems to variations in their design parameters. Technique for computing the sensitivity of temperature distributions to changes in processing parameters needed to decide the more effective laser input parameters for laser surface hardening treatment is considered. In this study, a state equation governing the heat flow in laser surface treatment is analyzed using a three-dimensional finite element method and sensitivity data of the processing parameter obtained using a direct differentiation method is applied to the sensitivity analysis. The interesting processing parameters are taken as the laser scan velocity and laser beam radius ( $r_{ b}$), and the sensitivities of the temperature T versus v and $r_{b}$ are analyzed. These sensitivity results are obtained with another parameters fixed. To verify the numerical analysis results, hardened layer dimensions (width and depth) of the numerical analysis are compared with the experimental ones.nes.

• Structural Engineering and Mechanics
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• 제76권5호
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• pp.561-578
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• 2020

The present work addresses the surface integrity and chip morphology in finish hard turning of AISI D3 steel under nanofluid assisted minimum quantity lubrication (NFMQL) condition. The surface integrity aspects include microhardness, residual stress, white layer formation, machined surface morphology, and surface roughness. This experimental investigation aims to explore the feasibility of low-cost multilayer (TiCN/Al2O3/TiN) coated carbide tool in hard machining applications and to assess the propitious role of minimum quantity lubrication using graphene nanoparticles enriched eco-friendly radiator coolant based nano-cutting fluid for machinability improvement of hardened steel. Combined approach of central composite design (CCD) - analysis of variance (ANOVA), desirability function analysis, and response surface methodology (RSM) have been subsequently employed for experimental investigation, predictive modelling and optimization of surface roughness. With a motivational philosophy of "Go Green-Think Green-Act Green", the work also deals with economic analysis, and sustainability assessment under environmental-friendly NFMQL condition. Results showed that machining with nanofluid-MQL provided an effective cooling-lubrication strategy, safer and cleaner production, environmental friendliness and assisted to improve sustainability.

• 한국생산제조학회지
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• 제9권2호
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• pp.52-58
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• 2000

the quality of a TV is closely connected with the high quality surface of Braun tube. To get high quality surface an improved grinding system is needed. It has three main parts : the housing part of supporting frame the outershaft part rotat-ed by motor and the innershaft part having eccentricity from the rotation axis of the outershaft. the housing part and the outershaft part are connected by outerbearings, The outershaft part and the innershaft part are connected by innerbearings. Although the outershaft part is rotated at high-speed the innershaft part is not rotated by offset coupling. The high quality grinding surface can be obtained by this mechanism of panel surface grinder, Because the innershaft is unbalanced by eccentricity from rotation axis of outershaft the unbalancing vibration is resulted In this rotor system with high-speed rota-tion the unbalancing vibration makes the opertion unstable. In this research the transfer function is obtained bythe frequency response analysis of finite element model. The simu-lation result is proved by comparing with the experimental result measured by signal analyzer Then the results are corre-lated. in order to improve the design an optimization method is used instead of two-planes balancing method The parts of the 3-dimensional panel surface grinder satisfy the each constraint, The result shows that the design of the panel surface grinder can be optimized.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.351-355
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• 2003

Screening 실험을 통하여 결정된 주요인자인 sucrose, nitrogen, 배양온도로 인자의 최적수준을 결정하는 표면반응법중 하나인 Box-Behnken design을 수행하였다. 각 인자의 상관관계를 통하여 sucrose는 90 g/L, nitrogen은 41 mM, 온도는 $22^{\circ}C$가 최적수준으로 결정이 되었으며 확인실험을 통하여 대조구보다 세포생장이 증가하였을 뿐만 아니라 hGM-CSF의 생산도 약 2배 정도 증가되었음을 확인하였다. 이것은 고농도의 sucrose로 인해 배지내로의 hGM-CSF의 분비가 촉진되었기 때문이며 또한 저온으로 인해 분비된 hGM-CSF를 분해하는 protease 활성이 감소되었기 때문인 것으로 사료된다.

• 한국정밀공학회지
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• 제22권1호
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• pp.167-174
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• 2005

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• 동력기계공학회지
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• 제2권2호
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• pp.81-86
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• 1998

The dynamic response characteristics of Tension Leg Platforms(TLPs) in waves are examined for presenting the basic data for design of TLPs. The numerical approach is based on a combination of the three dimensional source distribution method and the dynamic response analysis method, in which the superstructure of TLP is assumed to be flexible instead of rigid. Restoring forces by hydrostatic pressure on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the motion and structural analysis. Numerical results are compared with the experimental ones, which are obtained in the literature, concerning the motion and tension responses of a TLP in waves. The results of comparison confirmed the validity of the proposed approach.