본 연구는 중학생들이 온실 효과와 지구 온난화를 이해하고, 이를 지구 복사 평형 관점에서 설명할 수 있는지 심층적으로 살펴보고자 하였다. 이를 위해 ‘대기권과 날씨’ 대단원 수업을 완료한 중학교 3학년 118명의 학생을 대상으로, 복사 평형, 온실 효과, 지구 온난화에 대한 선택형 및 서답형으로 구성된 학생 이해 온라인 평가를 2021년 7월 13 일부터 7월 24일까지 실시하였다. 최종적으로 97명의 학생 응답을 수집하여 분석한 결과, 과반수(61.9%)가 넘는 학생들이 복사 평형의 의미를 옳게 기술하였으나 제시된 자료와 무관하게 사전 지식이나 구체적 사례를 들어 설명하는 경우가 많았다. 대부분의 학생들(92.8%)은 대기가 있는 지구에서 온실 효과가 나타나는 것을 알고 있었지만, 온실 효과를 복사 평형이 깨진 상태로 생각하는 경향이 높았으며(32.0%), 달과 지구 모두 복사 평형이 일어난다고 응답한 학생 (47.4%)은 절반에 미치지 못했다. 온실 효과의 원인으로 대기의 재복사를 찾아낸 학생은 다수(69.1%)였으나, 지구로 입사한 태양 복사량보다 방출한 지표 복사량이 더 크다고 응답한 학생은 소수(39.2%)에 불과하였다. 또한 절반 정도의 학생들(49.5%)이 온실 기체의 증가와 대기 흡수, 이로 인한 지표로의 재복사의 관계를 잘 이해하고 있었다. 그러나 온실 기체가 증가할 때, 지표 방출에 대해서는 증가(14.4%), 일정(9.3%), 감소(7.2%), 무응답(18.6%)으로 의견이 매우 다양하게 나타났다. 복사 평형, 온실 효과, 지구 온난화는 지구계의 균형과 상호작용이라는 빅 아이디어로 연결된 커다란 하나의 의미망이므로 학생들이 지구 온난화로 인한 기후 변화를 이해하고 적용하고 해석하는 개념 체계가 될 수 있다. 따라서 현재 인류에 닥친 기후 변화 위기와 관련해 학생들이 정확한 이해에 근거하여 과학적으로 사고하고 과학적 개념을 정립할 수 있도록, 정교한 프로그램 개발과 수업 경험을 제공하고 그 효과를 점검하는 후속 연구가 진행되어야 할 것이다.

The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. Based on the methodology performed in previous studies, the welding heat source was found through experiments and FEM under the welding power conditions of three cases and the parameters of the welding heat source were analyzed according to the welding power. In this study, parameters of fiber laser welding heat source according to welding power were searched through optimization algorithm and finite element analysis, and the correlation was analyzed. It was confirmed that the concentration of the welding heat source in the 1st layer was high regardless of the welding power, and it was confirmed that the concentration of the welding heat source in the 5th layer (last layer) increased as the welding power increased. This reflects the shape of the weld bead that appears during actual fiber laser welding, and it was confirmed that this study represents the actual phenomenon.

In this study, a welding heat source model was presented and verified during fiber laser welding. The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. It consists of a total of 12 parameters, and an optimization algorithm was used to find them. As optimization algorithms, adaptive simulated annealing, multi island genetic algorithm, and Hooke-Jeeves technique were applied for comparative analysis. The parameters were found by comparing the temperature distribution when the STS304L was bead on plate welding and the temperature distribution derived through finite element analysis, and all three models were able to derive a model with similar trends. However, there was a deviation between parameters, which was attributed to the many variables. It is expected that a more clear welding heat source model can be derived in subsequent studies by giving a guide to the relational expression and range between variables and increasing the temperature measurement point, which is the target value.

Welding is the most widely used technology for manufacturing in the automobile, and shipbuilding industries. Fiber laser welding is rapidly introduced into the field to minimize welding distortion and fast welding speed. Although it is advantageous to use finite element analysis to predict welding distortion and find optimized welding conditions, there are various heat source model for fiber laser welding. In this study, a welding heat source was proposed using a multi-layered heat source model that encompasses most of the existing various welding heat source models: conical shape, curved model, exponential model, conical-cylindrical model, and conical-conical model. A case study was performed through finite element analysis using the radius of each layer and the ratio of heat energy of the layer as variables, and the variables were found by comparing them with the actual experimental results. For case study, by applying Adaptive simulated annealing, one of the global optimization algorithms, we were able to find the heat source model more efficiently.

The estimation of heat source model is very important for heat transfer analysis with finite element method. Part I of this study used adaptive simulated annealing which is one of the global optimization algorithm for anticipating the parameters of the Goldak model. Although the analysis with 3D model which depicted the real situation produced the correct answer, that took too much time with moving heat source model based on Fortran and Abaqus. This research suggests the procedure which can reduce time with maintaining quality of analysis. The lead time with 2D model is reduced by 90% comparing that of 3D model, the temperature distribution is similar to each other. That is based on the saturation of heat transfer among the direction of heat source movement. Adaptive simulated annealing with 2D model can be used to estimate more proper heat source model and which could enhance to reduce the resources and time for experiments.

Anticipation of welding deformation with finite element method is a very interested topic in the industries, adequate heat source model is essential for concluding reasonable results. This study is related to estimate the parameters of Goldak heat source model, and global optimization algorithm is applied to this research. The heat affected zone (HAZ) boundary line of bead on plate (BOP) welding is used as the target, parameters of heat sources are used as the variables. Adaptive simulated annealing is applied and the optimal result is obtained out of 1,000 candidates. The convergence of finite element method and the global optimization is meaningful for estimation of welding deformation, which could enhance to reduce the resources and time for experiments.

This analyzed the competitive structure of heat pump by nationality, by year-on-year and by technology on patent pending thru patent information analysis and applied KISTI holding DWPI for it. Heat pump technology is expected to position at development period or at start point reaching puberty just got out development period and to be consistently developed thru patent portfolio analysis.