남한, 북한, 미국 등 세 행위자 간에는 복잡한 상호작용이 지속되며 전략적 삼각관계가 형성되어 왔다. 세 국가 간 관계에 적용돼 온 디트머의 전략적 삼 각관계 분석틀에 따르면 냉전기엔 ‘안정적 결혼’, 탈냉전기엔 ‘안정적 결혼’과 ‘로맨틱 삼각관계’ 사이의 과도기가 이어졌다. 하지만 북한이 대미 협상수단으 로서 핵개발 단계를 넘어 핵보유국 지위를 기정사실화하고, 미중 간 패권경쟁 과 ‘한미일 대 북중러’라는 구도가 본격화된 신냉전기에 들어서면서 남북미 간 전략적 삼각관계는 무너졌다. 하노이 회담 결렬 이래 미국과의 대화에 목매지 않고 대미 장기전체제에 돌입한 북한은 남한과의 대화도 철저히 단절한 채 동 맹국들과의 관계에만 몰두하고 있다. 북한의 핵 무력 완성으로 비핵화라는 목 표가 불가능에 가까워지고 ‘군축’이 최선책이 된 가운데 현재 중국과 러시아를 상대하느라 여력이 없는 바이든 정부에도 북한문제는 후순위로 전락해 소극적 인 대북정책을 펼치고 있다. 하지만 남북미 간 상호작용이 아예 끊겨버린 지금 이 오히려 북한의 배신행위 아래 불안정하게 유지되어 오고 있던 현재까지의 남북미 관계가 새롭게 거듭나는 중요한 기회일 수 있다. 기회가 오기까지 남북 관계에서의 긴장 국면이 확전되지 않도록 잘 관리하는 것이 현재 한국 정부의 과제일 것이다.

Although the Ti–6Al–4V alloy has been used in the aircraft industry owing to its excellent mechanical properties and low density, the low formability of the alloy hinders broadening its applications. Recently, laser-powder bed fusion (L-PBF) has become a novel process for overcoming the limitations of the alloy (i.e., low formability), owing to the high degree of design freedom for the geometry of products having outstanding performance used in hightech applications. In this study, to investigate the effect of bulk shape on the microstructure and mechanical properties of L-PBFed Ti-6Al-4V alloys, two types of samples are fabricated using L-PBF: thick and thin samples. The thick sample exhibits lower strength and higher ductility than the thin sample owing to the larger grain size and lower residual dislocation density of the thick sample because of the heat input during the L-PBF process.

The purpose of this study was to examine changes in serving frequency of elementary school meal before and after the COVID-19 pandemic. Number of menus provided in June and July of 2019 and 2020 were compared for 300 elementary schools in Korea. As a result, the serving frequency of la carte and dessert was increased after COVID-19. In addition, frequencies of main dishes such as pork cutlet, chicken, sweet and sour pork, hamburger steak, and so on using processed food were increased after COVID-19. Because of the longer serving time due to staggered serving, cook's working time for serving meals became longer. Therefore, it was judged that the number of servings of processed food was increased rather than the menu with a large amount of preprocessing work. Moreover, among desserts, fruits showed increased serving frequency. Serving frequencies for juice and dairy products were also increased. However, increased servings of juice and dairy products could increase sugar intake. Thus, a careful plan for menu composition is needed to provide balanced nutrients to students under emergency situations such as an infectious disease.

Because magnets fabricated using Nd-Fe-B exhibit excellent magnetic properties, this novel material is used in various high-tech industries. However, because of the brittleness and low formability of Nd-Fe-B magnets, the design freedom of shapes for improving the performance is limited based on conventional tooling and postprocessing. Laserpowder bed fusion (L-PBF), the most famous additive manufacturing (AM) technique, has recently emerged as a novel process for producing geometrically complex shapes of Nd-Fe-B parts owing to its high precision and good spatial resolution. However, because of the repeated thermal shock applied to the materials during L-PBF, it is difficult to fabricate a dense Nd-Fe-B magnet. In this study, a high-density (>96%) Nd-Fe-B magnet is successfully fabricated by minimizing the thermal residual stress caused by substrate heating during L-PBF.

This study compares and analyzes changes in users’ perceptions of industrial catering food service quality before and after COVID-19. The survey enrolled 226 subjects at five industrial catering establishments in Seoul and Gyeonggi Province; a total of 204 customers with complete data were included in the final analysis. Factor analysis was conducted to verify convergence validity and construct reliability; results pertaining to ‘service and environmental hygiene’ and ‘quality of food’ were extracted. Among the general variables of food service quality, differences were obtained in the user’s perceptions of food service qualities according to gender, education, and marital status. Our results revealed that women, low education, and married people perceived significant differences in all attributes before and after COVID-19. Additionally, varied altered perceptions were determined for service quality according to the occupations of the subjects. However, no differences were obtained for pleasant dining environment in the ‘service and environmental hygiene factor’ and variety of desserts in the ‘food quality factor’.

Isoflavones found in soybeans are present as glycosides and aglycones, which differ according to their chemical structure. The absorption rate and bioavailability of aglycones are greater than those of glycosides. It is known that aglycone isoflavones in soybean was converted from glycoside isoflavones by activating of endogenous β-glucosidase under drying (40~60℃) conditions after soaking. In this study, we compared and analyzed the proximate composition and isoflavone contents of soybean powders prepared under dried after soaking were analyzed. In the comparison of the proximate compositions, the moisture contents of white soybean powder dried after soaking (WSPDS) and black soybean powder dried after soaking (BSPDS) were decreased as compared with those of the control white soybean powder (CWSP) and control black soybean powder (CBSP). Whereas the contents of other proximate compositions were increased. The aglycone isoflavone contents were higher in WSPDS than in CWSP. Whereas the aglycone isoflavone contents of BSPDS had a similar content those of CBSP because of the component characteristics of black soybean. In conclusion, we believe that it is appropriate to identify and utilize the component characteristics of soybean varieties in order to induce an increase in the functional component content of soybeans under drying conditions after soaking.

완공된 건물과 달리 시공 중인 건물은 설계단계와 다른 하중 작용 및 콘크리트 강도 미발현 등 다양한 요인에 의해 설계단계에서 검 토한 하중을 초과하는 하중이 작용하여 건물의 안전성에 문제가 생길 위험이 있다. 또한 시공 중인 건물에 지진이 발생할 경우 더 큰 피해가 발생할 가능성이 있다. 따라서 이 연구는 전형적인 다양한 규모의 5층, 15층, 25층, 60층 예제모델을 작성하고 골조완성도에 따 른 시공단계 모델을 통해 시공 중인 건물의 지진하중의 영향을 분석하였다. 시공 중인 건물의 시공기간은 완공단계 이후의 사용기간 에 비해 매우 짧으므로 설계단계와 동등한 수준의 지진을 적용하는 것은 과도한 하중이 적용될 수 있으므로 시공단계 모델에 재현주 기 50~2,400년의 지진을 적용하여 지진하중을 검토하고 부재단면성능을 분석하였다. 그 결과 설계단계를 초과하는 하중의 여부 및 구조적 안전성 확보가 가능한 수준의 지진재현주기를 검토할 수 있었다. 또한 각 예제모델의 시공기간을 가정하여 시공기간에 따른 지진재현주기를 선정하고 선정한 재현주기의 설계 적절성을 확인하였다.

Since delivery food has become a new dietary culture, this study examines consumer awareness through big data analysis. We present the direction of delivery food for healthy eating culture and identify the current state of consumer awareness. Resources for big data analysis were mainly articles written by consumers on various websites; the collection period was divided into before and after COVID-19. Results of the big data analysis revealed that before COVID-19, delivery food was recognized as a limited product as a meal concept, but after COVID-19, it was recognized as a new shopping list and a new product for home parties. This study concludes by suggesting a new direction for healthy eating culture.

This article focuses on the Namdaemum repair and the Seokguram restoration, which had begun in 1961, as an important repair conducted during the time of seeking the conservation principle of architectural heritage after liberation in Korea. Through the analysis of the principles described in the repair report issued after the two repairs, meeting records, and related expert announcements, it is shown that the principle of 'preservation of the historic state' had been established at Namdaemun repair and later have changed to the principle of 'restoration of the historic form' which means reconstruction in Seokguram restoration. By analyzing the minutes of the Cultural Heritage Committee's meeting on the repair of other cultural properties during this period, it is revealed that the key terms related to the preservation principle, 'historic form' and 'restoration', were given meaning as 'object' and 'method' of preservation, and then 'restoration of the historic form' has been gradually used as a conservation principle.

세계 5대 갯벌해역으로 유명한 한국 서해 경기만의 기후변화 영향을 파악하고, 기후변화 영향을 최소화하기 위한 적응방안 연 구하였다. 경기만의 기후변화 영향으로 2100년에 수온은 1.2 ℃ 증가하고, 염분이 1.1 PSU 감소하며, 해수면은 35.2 cm 상승하는 것으로 예 측되었다. 또한 해수면 상승의 효과로 150.5 km2의 해안지역이 침수될 것으로 예상되었다. 기후변화로 인한 경기만 생태환경 영향을 최소 화하기 위한 적응대책으로는 1) 경기만 자체 자연환경의 적응능력 유지를 위한 지원, 2) 생물 서식지 확보를 위한 인간 활동 조정 등 두가 지 방안이 제시되었다.