Even though Mod is a cutting-edge business model that benefits a variety of multi-sided market participants, empirical research on Mod, the value co-creation activity of game users and game developers, is hard to come by. This study intends to look into how the combination of the Mod and the IP from the prior game affects user engagement. An experiment was carried out with Korean university students to examine the hypotheses. User engagement was found to increase with the use of the Mod and the IP from the previous games. On the other side, it was discovered that the impact of mod games on user engagement did not differ significantly from non-mod games when the previous game's IP was absent. The study's findings help establish the framework for afterwards empirical research by showing the effect of mod on user engagement.

In this study, we investigated the effect of the residual carbides and tempered carbides precipitated by tempering treatment after quenching on the pitting corrosion of mod. 440A martensitic stainless steel. In quenched specimens and tempered specimens after quenching of mod. 440A martensitic stainless steel, the volume fraction of the residual carbides and total carbides decreased with the increase of the austenitizing temperature. Pitting resistance increased with the increase of austenitizing temperature. With the increase of the volume fraction of the residual and total carbides, the pitting resistance of mod. 440A martensitic stainless steel was decreased. The pitting resistance of mod. 0.5C-17Cr-0.5Ni 440A martensitic stainless steel had stronger affected by residual carbides than precipitated carbides produced by tempering.

본 연구는 국내에 보급되어 있는 여러 형태의 이유자돈사에 대하여 CFD(Computational Fluid Dynamics) 컴퓨터 시뮬레이션을 통해 가상으로 모델화하여 특성을 비교 분석하고 실제 돈사에서 각종환경요인과 이유자돈의 증체율 및 폐사율을 비교 분석함으로써 우리나라의 기후 조건에 적합한 모델을 제시하기 위하여 수행되었다. 실험돈사로는 복도-더그매 예열 음압환기방식 무창이유자돈사(Model-1), 더그매 예열 음압환기방식 무창이유자돈사(Model-2), 그리고 윈치커튼형 음압환기방식 개방이유자돈사(Model-3)가 이용되었다. 시뮬레이션 결과 Model-1이 Model-2와 Model-3에 비하여 전체적으로 낮은 풍속과 균일한 풍속분포도를 나타냈으며 모델간의 평균 온도, 평균 상대습도 및 평균 암모니아 농도가 차이가 없었으나(p>0.05) Model-1과 Model-3의 종료체중과 일당증체량이 Model-2에 비해 높았다(p<0.001). 따라서 Model-1이 Model-2와 Model-3에 비하여 우리나라의 기후 조건에 적합한 것으로 판단되었다.

In this study, mechanical tests and microstructural analyses including TEM analyses with EDX of precipitates in modified 9Cr-1Mo steel were carried out to determine the cause of embrittlement observed after heat-treatment, which limits the usage of the alloy for power plants. Mod. 9Cr-1Mo steel specimens at austenite temperature were quenched to the molten salt baths at 760˚C and 700˚C, in which the specimens were kept for 10 min ~ 10 hr with subsequent air-cooling. Impact tests showed that the impact value dropped abruptly when the specimens were kept longer than 30 min at ~760˚C reaching to minima in about 1 hr, and then increasing at further retention. The tensile strength of the specimens reached the minimum value without much change afterward, whereas the values of elongation showed the same trend as that of the impact value. The isothermally heat-treated steel at 700˚C also showed a minimum impact value in about 1 hr. These results suggest that the isothermal heattreatment at 760 and 700˚C for about 1 hr induces temporal embrittlement in Mod. 9Cr-1Mo steel. The microstructural examination of all the specimens with extraction replica of the carbides revealed that the specimens with temporal embrittlement had Cr2C, indicating that the cause of the embrittlement was the precipitation of the Cr2C. In addition, TEM/EDX results showed that the Fe/Cr ratio was 0.033 to 0.055 for Cr2C, whereas it was 0.48 to 0.75 for Cr23C6, making the distinction of the Cr2C and Cr23C6 possible even without direct electron diffraction analyses.

It is well known that modified 9Cr-1Mo steel has a low thermal expansion and high thermal conductivity with excellent high temperature properties compared to austenitic stainless steel. For these advantages, the steel is very popular for the boiler tube of thermal power plants. Normalizing is commonly utilized to obtain martensite in this steel, which shows an unusual toughness for martensite. However, some accidents related to this steel have been reported recently, opening the necessity for further study. As a particular behavior of the steel, an abrupt drop of the impact value has been identified upon tempering at 750˚C for about 1 hour. It is well known that Fe3C forms during autotempering and turns to Cr2C at an early stage and then transforms to Cr23C6. In this study, the cause of the abrupt drop of the impact value was investigated with an impact test, microstructural observation, nanodiffraction and phase analyses using instruments such as optical and transmission electron microscopes (TEM) with an extraction carbon replica of the carbides. The analyses revealed that the M2C that formed when retained for about 1 hour at 750˚C causes a drastic decrease in the mechanical properties. The sharp drop in mechanical properties, however, disappeared as the M2C transformed into M23C6 with longer retention.

We fabricated YBCO film using a TFA-MOD method. In order to enhance the reaction kinetics and to control the formation of the second phases, and powders were used as precursors (the so called "211 process"). The films were calcined at and then fired at in a 12.1% humidified atmosphere. We found that the microstructure varied significantly with the firing temperature. The textures of all of the films were similar and mainly biaxial. For the film fired at , the critical current was obtained to be 39 A/cm-width (corresponding critical current density is 2.0 MA/).

게임은 이용하는 사람이 선택할 수 있는 자율성의 폭이 넓은 열린 문화(open culture)이다. 즉, 게임 소비자의 참여가 적극적으로 요구되고 수용된다. 그런 의미에서, 원작 게임에 여러 가지 변형을 가하는 모드(MOD)는 게임 이용자의 적극적인 참여를 나타내는 대표적인 사례이자 게임 제작 과정에서 소비자의 참여 가능성을 보여주는 예시이다. 본 연구는 모드 게임의 대표적인 사례 중 Half-Life 모드의 분석을 통해, 게임 제작 과정의 발전적 측면에서 본 소비자 참여 가능성에 대해 논의한다.