• 기술혁신학회지
• /
• 제12권1호
• /
• pp.212-236
• /
• 2009

본 연구는 차세대 컨버전스서비스를 대상으로 고객, 기술, 사업자, 규제의 4대 이슈별로 환경 불확실성요인을 규명하고, 이들 환경 불확실성요인 중 특히 핵심이 되는 불확실성 요인을 도출하였다. 이어 도출된 핵심불확실성요인(KUF: Key Uncertainty Factor)을 중심으로 환경의 잔여불확실성 수준에 대한 평가를 시나리오 플래닝에 의해 실시하고, 이를 기반으로 차세대 컨버전스서비스의 진입전략 수립을 위한 방향을 제시하였다. 본 연구의 차세대 컨버전스서비스 사업의 불확실성 평가 및 진입 시나리오 구성에 대한 연구결과를 종합하면 다음과 같다. 2가지 잔여 불확실성 수준(선택 가능한 미래 수준, 예측 범위의 미래 수준)의 6개 시나리오를 대상으로 각각의 전략적 속성을 평가한 결과 시장 진입의 성공 요소로 2가지 핵심성공요인(KSF: Key Success Factor)을 도출하였다. 즉, 고객수요추세, 광고규제 완화를 핵심성공요인(KSF: Key Success Factor)으로 도출하였으며, 이를 토대로 4가지 전략적 시나리오 유형 및 각 시나리오 별 요구되는 사업자 대응역량에 대한 방향성을 제시하였다. 본 연구의 결과는 컨버전스 시장의 활성화는 물론 관련 사업자의 자원의 효율적 배분, 진입형태, 진입 적정시기 등 진입전략 수립에 많은 시사점을 제공할 것이다.

• 대한기계학회논문집
• /
• 제18권11호
• /
• pp.2932-2943
• /
• 1994

An efficient approach to the automatic construction of effective quadrilateral finite element meshes for two-dimensional analysis is presented. The procedure is composed of, firstly, an initial mesh generation and, secondly, an h-version of adaptive refinement based on error analysis. As for an initial mesh generation scheme, a modified looping algorithm has been employed. For the adaptive refinement process, an error indicator obtained by computing the residual error of the equilibrium equations in the energy norm with a relaxation factor has been employed. Examples of mesh generation and self-adaptive mesh improvements are given. These example solutions demonstrate that an effective mesh for a given error tolerance can be obtained in a few steps of the analysis processes.

• 대한기계학회논문집A
• /
• 제38권7호
• /
• pp.809-815
• /
• 2014

최근들어 원자력 발전소에 유도 가열 공정으로 굽힌 배관을 적용하려는 동향이 있다. 이러한 유도 가열 굽힘 공정 동안의 열-기계적 메커니즘에 의해 잔류응력이 발생할 수 있다. 잔류응력은 균열 발생과 성장에 중요한 영향을 미치는 균열 구동력들 중의 하나이다. 그러나, 기존 연구들은 두께 변화, 타원도와 같은 기하학적 형상 변이에 집중하고 있는 반면 공정 변수가 잔류응력에 미치는 영향과 관련된 연구는 찾아보기 힘들다. 본 연구에서는 316 오스테나이트 스테인리스 강으로 제작된 유도 가열 굽힘 배관의 잔류응력 분포에 미치는 공정 변수의 영향을 유한요소 변수 해석을 통해 고찰하였다. 고찰결과, 굽힘 모멘트와 굽힘 각도는 잔류응력에 미치는 영향이 미미한 반면 유도 가열률과 이송 속도는 잔류응력에 상당한 영향을 미침을 확인하였다.

• 한국수소및신에너지학회논문집
• /
• 제22권4호
• /
• pp.534-545
• /
• 2011

This paper describes the evaluation of kinetic parameters for pyrolysis and carbon char oxidation of residual oil. The non-isothermal pyrolysis of residual oil was carried out with TGA (Thermo-Gravimetric Analyzer) at heating rate of 2, 5, 10 and $20^{\circ}C/min$ up to $800^{\circ}C$ under N2 atmosphere. The first order and nth order pyrolysis models were used to fit the experimental data, and the nth order model was turned out to follow the experimental data more precisely than the first order model. For carbon char oxidation experiment, TGA and four heating rates used in pyrolysis experiment were also adapted. The kinetic parameters for the residual carbon char particle were obtained with three char oxidation model, that is, volume reaction, grain and random pore model. Among them, the random pore model described the char oxidation behaviour quite well, compared to other two models. The non-linear regression method was used to obtain kinetic parameters for both pyrolysis and carbon char oxidation of residual oil.

• Corrosion Science and Technology
• /
• 제17권1호
• /
• pp.12-19
• /
• 2018

Langelier Index (LI) is used as a tap water corrosiveness index. Residual chlorine in tap water induces corrosion inside water pipes. This study takes a deeper look into the effect of residual chlorine in water pipes. Comparison between tap waters of Y and K water treatment plant (WTP) shows that the LI index of K WTP is lower than that of Y. However, the corrosion rate of Y WTP is higher than that of K WTP. This means that the higher the concentration of residual chlorine in tap water, the higher the corrosion rate of pipe materials. When calcium hydroxide was added to tap water, the corrosiveness index was improved and thus the corrosion rate reduced. It is possible to increase the disinfection efficiency by increasing the duration of residual chlorine and suppressing the rust generation of water pipes and to supply minerals. A guideline for corrosion control with residual chlorine should be set up. The effects of residual chlorine should be included in the corrosiveness index of tap water.

• 한국환경과학회지
• /
• 제25권5호
• /
• pp.737-744
• /
• 2016

For electrolysis process using an insoluble electrode, electrochemical performance was greatly affected by the manufacturing method and procedure, such as the firing temperature, pre-treatment, type of precursor solution, coating method, electrode material, etc. Components of the electrode therein is one of the most important factors in electrochemical reaction. To achieve such characteristics, a appropriate ratio of the electrode material should be carefully chosen. The aim of this research was to apply experimental design method in the optimization of electrode component for the maximum generation of oxidants in electrochemical oxidation process. Mixture design, especially expanded simplex lattice design, in DOME (design of mixture experiments) with Design Expert - commercial software - was used to analyze the data. Analysis of variance (ANOVA) showed a high coefficient of determination ($R^2$) value of 0.9470, thus ensuring a satisfactory adjustment of the $3^{rd}$ order special cubic regression model with the experimental data. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the TRO generation concentration and independent variables(mol ratio of 3 electrode components) in a real unit: TRO generation concentration $(mg/L)=TRO\;conc.=98.25{\times}[Ir]+49.71{\times}[Sn]+95.29{\times}[Sb]-16.91{\times}[Ir]{\times}[Sn]-29.47{\times}[Ir]{\times}[Sb]-22.65{\times}[Sn]{\times}[Sb]+703.19{\times}[Ir]{\times}[Sn]{\times}[Sb]$. The optimized formulation of the 3 component electrode for an high TRO (total residual oxidants) generation was acquired at mol ratio of Ir 0.406, Sn 0.210, Sb 0.384 (desirability d value, 1).

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.633-636
• /
• 2005

Imprint lithography is a promising method for high-resolution and high-throughput lithography using low-cost equipment. As with other nanoimprint methods, ultraviolet-nanoimprint lithography (UV-NIL) resolution appears to be limited only by template resolution, and offers a significant cost of ownership reduction when compared to other next generation lithography (NGL) methods such as EUVL and 157 nm lithography. The purpose of this paper is to suggest optimum values of control parameters of Imprio 100 manufactured by Molecular Imprint, Inc., which is the first commercially available UV-NIL tool, for sound nanoimprint. UV-NIL experiments were performed on Imprio 100 to find dispensing recipe for avoiding air entrapment. Dispensing recipe related to residual layer thickness and uniformity was optimized and 40 nm thick residual layer was achieved.

• Journal of Welding and Joining
• /
• 제17권5호
• /
• pp.77-82
• /
• 1999

Resistance spot welding process is completed in very short time and there are many factors affecting on the generation of heat. It is difficult to control these experimental factors and monitor distribution of the temperature and stresses in the experimental analysis case. and too much time and expense are required for the experimental trials to fine proper welding condition. So numerical analyses have been attempted steadily, but most numerical analyses on the resistance spot welding are mainly focused on thermal behavior. Therefore, in this paper, the numerical analysis of mechanical behavior as well as heat conduction is carried out for the spot welding process. For this numerical analysis, axial symmetric computer program for the spot welding analysis by F.E.M. has been developed considering heat conduction and thermal elastic-plastic theory. Material properties depending on temperature such as density, heat conductivity, heat expansion coefficient, specific heat, yield stress, elastic modulus, and specific resistance are considered. Using the results of temperature distribution obtained from heat conduction analysis, the thermal elastic-plastic analysis is carried out to clarify mechanical behavior of spot welded specimen. In order to evaluate the effect of residual stresses, numerical analyses are carried out under tension-shear load in two cases respectively; one with residual stress, the other without residual stresses.

• 반도체디스플레이기술학회지
• /
• 제9권4호
• /
• pp.19-23
• /
• 2010

Nanoimprint lithography (NIL) is one of the most versatile and promising technology for micro/nano-patterning due to its simplicity, high throughput and low cost. Recently, one of the major trends of NIL is large-area patterning. Especially, the research of the application of NIL to TFT-LCD field has been increasing. Technical difficulties to keep the uniformity of the residual layer, however, become severer as the imprinting area increases. In this paper we performed a numerical study for a large area NIL (the $2^nd$ generation TFT-LCD glass substrate ($370{\times}470$ mm)) by using finite element method. First, a simple model considering the surrounding wall was established in order to simulate effectively and reduce the computing time. Then, the volume of fluid (VOF) and grid deformation method were utilized to calculate the free surfaces of the resist flow based on an Eulerian grid system. From the simulation, the velocity fields and the imprinting pressure during the filling process in the NIL were analyzed, and the effect of the surrounding wall and the uniformity of residual layer were investigated.

• 한국응용곤충학회지
• /
• 제40권1호
• /
• pp.83-88
• /
• 2001

Imidacloprid의 벼멸구에 대한 약효 지속효과와 벼체내 함유량과의 관계를 구명하기위해 imidacloprid 입제를 추천량 (0.3 kg a.i./ha), 추턴 약량의 1/2 (0.15 kg a.i/ha), 114 (0.075 kg a.i./ha) 약량으로 수중 처리하였으며 액제를 추천농도(0.032kg a.i./ha), 추천농도의 112(0.016kg a.i./ha), 1/4 (0.008 kg a.i./ha)의 농도로 벼에 경엽 처리한 후 시기별로 벼멸구를 접종, 사충수를 조사하였고 그 때의 벼체내 약제 함유량을 조사하였다 Imidacloprid 입제의 추천 약량을 처리하였을 경우 약 효(100% 살충률)가 40일까지 지속되었으며, 추천량의 1/2, 1/4 약량에서는 접종세대에 대한 치사효과가 각각 30, 20일가지 지속되었다. Imidacloprid 액제는 추천농도와 1/2농도 처리에서는 접종세대에 대한 약효지속효과가 약제처리 후 40일까지 지속되었으며, l/4농도로 처리한 경우에는 처리 후 30일까지 지속되었다. Imldacloprid입제나 액제 모두 약효 지속기간이 길어 처리 농도에 따라 약간의 차이는 보이나 약 30일 정도 약효가 지속되었다. 파종 전 종자 분의 처리 (3g/볍씨 1kg)의 경우 약제처리 후 55일가지 약효를 나타냈으며 60일부터는 점차적으로 살충력이 낮아지는 경향을 보였다. Imidacloprid 입제를 약량별로 처리한 후 도체 내 잔류량을 시일 별로 조사한 결과 추천량 처리시 처리 1일 후부터 잔류량이 점차적으로 증가되어 6일차에 0.46ppm으로 최고치를 나타낸 후 차차 감소되어 처리40일경에는 0.09ppm이 되었다. 1/2약량, 1/4약량 처리에서도 처리 후 6일경에 잔류량이 각각 0.23ppm, 0.2ppm으로 최고 치에 도달한 후 점차적으로 감소되는 경향을 보였다. Imidacloprid 액체를 추천농도와 추천농도의 1/2, 추천농도의 1/4로 처리한 후의 도체 내 잔류량은 처리 직후 각각 2,0. 6,0. 0.2ppm의 잔류량을 보였고, 처리 후 10일경에는 1/2, 1/4 농도처리 의 잔류량은 추천농도의 잔류량과 각각 7배와 11배의 차이를 보였다.