• 반도체디스플레이기술학회지
• /
• 제21권1호
• /
• pp.148-154
• /
• 2022

As the 4th industrial age approaches, the demand for semiconductors is increasing enough to be used in all electronic devices. At the same time, semiconductor technology is also developing day by day, leading to ultraprecision and low power consumption. Semiconductors that keep getting smaller generate heat because the energy density increases, and the generated heat changes the shape of the semiconductor package, so it is important to manage. The temperature change is not only self-heating of the semiconductor package, but also heat generated by external damage. If the package is deformed, it is necessary to manage it because functional problems and performance degradation such as damage occur. The package burn in test in the post-process of semiconductor production is a process that tests the durability and function of the package in a high-temperature environment, and heat dissipation performance can be evaluated. In this paper, we intend to review a new material formulation that can improve the performance of the adapter, which is one of the parts of the test socket used in the burn-in test. It was confirmed what characteristics the basic base showed when polyamide, a high-molecular material, and alumina, which had high thermal conductivity, were mixed for each magnification. In this study, functional evaluation was also carried out by injecting an adapter, a part of the test socket, at the same time as the specimen was manufactured. Verification of stiffness such as tensile strength and flexural strength by mixing ratio, performance evaluation such as thermal conductivity, and manufacturing of a dummy device also confirmed warpage. As a result, it was confirmed that the thermal stability was excellent. Through this study, it is thought that it can be used as basic data for the development of materials for burn-in sockets in the future.

• 한국지진공학회논문집
• /
• 제27권5호
• /
• pp.203-211
• /
• 2023

For fast-built and safe precast concrete (PC) construction, the dry mechanical splicing method is a critical technique that enables a self-sustaining system (SSS) during construction with no temporary support and minimizes onsite jobs. However, due to limited experimental evidence, traditional wet splicing methods are still dominantly adopted in the domestic precast industry. For PC beam-column connections, the current design code requires achieving emulative connection performances and corresponding structural integrity to be comparable with typical reinforced concrete (RC) systems with monolithic connections. To this end, this study conducted the standard material tests on mechanical splices to check their satisfactory performance as the Type 2 mechanical splice specified in the ACI 318 code. Two PC beam-column connection specimens with dry mechanical splices and an RC control specimen as the special moment frame were subsequently fabricated and tested under lateral reversed cyclic loadings. Test results showed that the seismic performances of all the PC specimens were fully comparable to the RC specimen in terms of strength, stiffness, energy dissipation, drift capacity, and failure mode, and their hysteresis responses showed a mitigated pinching effect compared to the control RC specimen. The seismic performances of the PC and RC specimens were evaluated quantitatively based on the ACI 374 report, and it appeared that all the test specimens fully satisfied the seismic performance criteria as a code-compliant special moment frame system.

• International Journal of Advanced Culture Technology
• /
• 제11권3호
• /
• pp.277-296
• /
• 2023

The South Korean ethnic diaspora US lobby shows efficacy as an interest group in generating influence in American foreign and domestic public policy making. The persuasive portrayal of South Korea as a critical Cold War US ally reinforced US amenability to pro-South Korea lobbying. Also, the South Korean US diaspora is a comparatively recent immigrant group, thus its lingering resistance to assimilation facilitates its political mobilization to lobby the US government. One source of this influence includes the foundational legacy of proselytizing Western and particularly American religious social movement representatives in Korean religiosity and society. US protestant Christianity acquired a strong public association with emerging Korean nationalism in response to Japanese imperialism and occupation. Hostility towards Japanese colonialism followed by the threat from Soviet-sponsored, North Korean Communism meant Christianity did not readily become a cultural symbol of excessive external, US interference in South Korean society by South Korean public opinion. The post-Cold War shift in US foreign policy towards targeting so-called rogue state vestiges of the Cold War including North Korea enhanced further South Korea's influence in Washington. Due to essential differences in the perceived historical role of American influence, extrapolation of the South Korean development model is problematic. US hegemony in South Korea indicates that perceived alliance with national self-determination constitutes the core of soft power appeal. Civilizational appeal per se in the form of religious beliefs are not critically significant in promoting American polity influence in target polities in South Korea or, comparatively, in the Middle East. The United States is a perceived opponent of pan-Arab nationalism which has trended towards populist Islamic religious symbolism with the failure of secular nationalism. The pronounced component of evangelical Christianity in American core community nationalism which the Trump campaign exploited is a reflection of this orientation in the US.

• 한국의류산업학회지
• /
• 제25권4호
• /
• pp.449-459
• /
• 2023

This study focuses on online communities and the ritual conversations of users when participating in sharing activities. The study aims to understand the social and psychological phenomena that occur between users within the context of Erving Goffman's impression management theory. Case studies and a content analysis were conducted by collecting posts and comments related to fashion products in the sharing activities category on Naver Cafe "Family Sale." On the one hand, the study identified various disposition motives among givers, including a desire for recognition, self-expression, activation of the community, emotional sympathy, goodwill, play, and simple disposition. On the other hand, receivers' purchase motives included the need for a product, reciprocation based on a sense of belonging, play, gift-giving, and simple response. Analyzing the posts of givers and the comments of receivers of fashion products using impression management strategies and dramaturgical analysis, the study interpreted users' impression management and revealed propensities in fashion consumption: fashionability, conspicuousness, value orientation, and economic feasibility. Through ritual conversations, users managed to attain emotional stability on an individual level, while they reinforced collective bonds on a social level. They fulfilled their roles with their own narratives to achieve personal and collective goals in a non-face-to-face situations and non-monetary transactions. This study is significant in that it examines normative communication in an online community and user relationships to understand a recent phenomenon in the fashion industry.

• 미래기술융합논문지
• /
• 제2권1호
• /
• pp.41-47
• /
• 2023

본 연구는 헬스케어분야를 전공하는 만학도를 대상으로 일과 학업병행에 따른 삶과 여가에 대한 이야기를 들어보고자 하였다. 이를 위해 4명의 만학도를 대상으로 일과 학업 병행과정에서 느끼는 일상의 내용을 중심으로 현재 삶과 여가, 여가의 긍정과 부정적인 점, 향후 삶과 여가에 대한 내용을 인터뷰와 함께 기술할 수 있도록 하였다. 이후 인터뷰 내용과 함께 기술내용을 상호보강하고 자기기입의 형식으로 서술하였다. 만학도의 일과 학업의 병행에서 여가시간의 감소는 삶의 질을 감소시킬 수 밖 에 없다. 하지만 본인의 학업의 목적과 여가의 균형을 잃지 않기 위해 저마다 노력을 하고 있었다. 만학도의 일과 학업 병행은 미래의 삶과 여가를 위한 선택이고 과정이다. 그 과정에서의 애환은 삶의 가치와 희망이라 생각된다.

• 한국지진공학회논문집
• /
• 제27권3호
• /
• pp.129-137
• /
• 2023

This study presents a dry precast concrete (PC) beam-column connection, and its target seismic performance level is set to be emulative to the reinforced concrete (RC) intermediate moment resisting frame system specified in ACI 318 and ASCE 7. The key features include self-sustaining ability during construction with the dry mechanical splicing method, enabling emulative connection performances and better constructability. Test specimens with code-compliant seismic details were fabricated and tested under reversed cyclic loading, which included a PC beam-column connection specimen with dry connections and an RC control specimen. The test results showed that all the specimens failed in a similar failure mode due to plastic deformations in beam members, while the hysteretic response curve of the PC specimen showed comparable and emulative performances compared to the RC specimen. Seismic performance evaluation was quantitatively addressed, and on this basis, it confirmed that the presented system can fully satisfy all the required performance for the intermediate RC moment resisting frame.

• 무역학회지
• /
• 제41권4호
• /
• pp.269-291
• /
• 2016

본 연구는 전략물자 자율준수체제(전략물자 CP)를 이와 유사한 국내 제도인 AEO 제도 및 공정거래 자율준수제도와 비교 분석하여, 전략물자 자율준수무역거래자제도(전략물자 CP)의 안정적이고 효과적인 운영을 위한 개선방안을 제시하고자 하는데 그 목적이 있다. 전략물자 CP를 효율적으로 개선하여 기업의 자율관리 역량을 강화하기 위해서는 교육 이수 요건을 구체화하고, 기업의 전략물자 판정능력에 대한 평가를 강화하며, 전략물자 CP를 적극적으로 도입하는 기업에 대해 특혜를 제공하여야 한다. 또한, 전략물자 CP의 확산과 내실화를 위하여 현재의 지정제 운영방식에서 등록 후 지정방식으로 전환하는 것을 고려해 볼 수 있으며, 전략물자 CP 제도의 성공적인 운영을 위하여 기업이 자체적으로 미비점을 개선할 수 있도록 사후관리를 강화할 필요가 있다.

• Tribology and Lubricants
• /
• 제39권6호
• /
• pp.235-243
• /
• 2023

This paper presents the fabrication process of water-lubricated plastic bearings. Plastic bearings require good mechanical properties and tribological properties as well as elasticity and shock resistance, especially when lubricated in dirty water conditions. In this study, sleeve-type plastic bearings are produced by winding a prepreg sheet, which primary contains nitrile rubber (NBR)-modified epoxy, self-lubricating fillers, and various types of lattice-structured reinforcing fibers such as carbon, Aramid, and polyethylene terephthalate. A thermosetting epoxy is chemically modified with NBR to impart elasticity and low-friction characteristics in water conditions. Experimental investigations are conducted to examine the mechanical and tribological characteristics of the developed bearing materials, and the results are compared with the characteristics of a commercial plastic bearing (Thordon SXL), well known as a water-lubricated bearing. A Thordon bearing (mainly composed of polyurethane) exhibits an extremely low load-bearing capacity and is thus only suitable for medium loading (1~10MPa). The tribological characteristics of the test materials are evaluated through Falex block-on-ring (LFW-1) friction and wear tests. The results indicate that friction exhibited by the carbon-fiber-reinforced NBR-10wt.%-modified epoxy composite material, incorporated with the addition of 20wt.% UHMWPE and 6wt.% paraffin wax, is lower than that of the Thorden bearings, whereas its wear resistance surpass that of Thorden ones. Because of these features, the load carrying capacity of the fabricated composite (>10MPa) is higher than that of the Thorden bearings. These results confirm the applicability of water-lubricated plastic bearing materials developed in this study.

• The Journal of Advanced Prosthodontics
• /
• 제16권2호
• /
• pp.91-104
• /
• 2024

PURPOSE. The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS. The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION. The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.

• 한국지진공학회논문집
• /
• 제28권2호
• /
• pp.85-92
• /
• 2024

This study presents code-compliant seismic details by addressing dry mechanical splices for precast concrete (PC) beam-column connections in the ACI 318-19 code. To this end, critical observations of previous test results on precast beam-column connection specimens with the proposed seismic detail are briefly reported in this study, along with a typical reinforced concrete (RC) monolithic connection. On this basis, nonlinear dynamic models were developed to verify seismic responses of the PC emulative moment-resisting frame systems. As the current design code allows only the emulative design approach, this study aims at identifying the seismic performances of PC moment frame systems depending on their emulative levels, for which two extreme cases were intentionally chosen as the non-emulative (unbonded self-centering with marginal energy dissipation) and fully-emulative connection details. Their corresponding hysteresis models were set by using commercial finite element analysis software. According to the current seismic design provisions, a typical five-story building was designed as a target PC building. Subsequently, nonlinear dynamic time history analyses were performed with seven ground motions to investigate the impact of emulation level or hysteresis models (i.e., energy dissipation performance) on system responses between the emulative and non-emulative PC moment frames. The analytical results showed that both the base shear and story drift ratio were substantially reduced in the emulative system compared to that of the non-emulative one, and it indicates the importance of the code-compliant (i.e., emulative) connection details on the seismic performance of the precast building.