https://scholar.dgist.ac.kr/handle/20.500.11750/56593 2026-04-04T18:06:45Z https://scholar.dgist.ac.kr/handle/20.500.11750/60083 Title: 친수성 표면 위에서 나노입자 현탁액 미세 액적의 퍼짐 역학 Author(s): 김현우; 정소현; 김호영 Abstract: 미세 액적(microdroplet)은 바이오 프린팅 및 하향식(bottom-up) 제조 기술에서 핵심적인 역할을 하며, 특히 고체 표면에서의 퍼짐(spreading) 거동 제어는 정밀도와 정확도를 결정하는 중요한 요소이다. 순수 액체의 퍼짐성에 대한 연구는 오랫동안 연구되어 왔지만(1~3), 입자 현탁액을 포함한 미세 액적의 퍼짐 거동에 대한 연구는 부족한 실정이다. 본 연구에서는 자체 제작한 잉크젯 시스템을 이용해 직경 50~80 μm 의 단일 미세 액적을 생성하고, 친수성 표면에서 다양한 크기의 입자를 포함하는 수성 미세 액적의 퍼짐 거동을 관찰하였다. 실험 결과, 동일한 Weber 수에서 나노입자 현탁액의 퍼짐 반경이 순수 물보다 더 크게 나타났다. 이를 이해하기 위해 나노입자의 브라운 운동과 입자 간 상호작용이 접촉선 이동성(contact line mobility)에 미치는 영향을 분석하고, 입자 크기(dp), 점도(μ), 기판 온도(T) 등의 변수를 조정하여 퍼짐 거동을 정량적으로 평가하였다. 2025-04-02T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58290 Title: Bioinspired and biohybrid soft robots: Principles and emerging technologies Author(s): Chen, Zhengkun; Chen, Jiafan; Jung, Sohyun; Kim, Ho-Young; Lo Preti, Matteo; Laschi, Cecilia; Ren, Ziyu; Sitti, Metin; Full, Robert J.; Yang, Guang-Zhong Abstract: Soft robots have drawn increasing attention due to their inherent flexibility, deformability, and adaptability. The natural world, with its evolutionary refinement, presents the best source of inspiration for building soft robots. Creatures with sophisticated soft bodies and delicate mechanisms can be ideal biological models. This perspective focuses on bioinspired and biohybrid soft robots, providing a comprehensive review of the latest research in this area. We introduce the state-of-the-art principles of soft robots according to actuation, material selection, and sensing techniques. Based on biological classification methods used in nature, current research progress on biomimetic soft robots in animals, plants, and microorganisms is described. Emerging areas of interests are also highlighted for different biological species. Additionally, this paper explores the potential application areas of soft robots across various domains, outlining future challenges and ongoing developments. © 2025 2025-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/12950 Title: Avian mud nest architecture by self-secreted saliva Author(s): Jung, Yeonsu; Jung, Sohyun; Lee, Sang-im; Kim, Wonjung; Kim, Ho-Young Abstract: Mud nests built by swallows (Hirundinidae) and phoebes (Sayornis) are stable granular piles attached to cliffs, walls, or ceilings. Although these birds have been observed to mix saliva with incohesive mud granules, how such biopolymer solutions provide the nest with sufficient strength to support the weight of the residents as well as its own remains elusive. Here, we elucidate the mechanism of strong granular cohesion by the viscoelastic paste of bird saliva through a combination of theoretical analysis and experimental measurements in both natural and artificial nests. Our mathematical model considering the mechanics of mud nest construction allows us to explain the biological observation that all mud-nesting bird species should be lightweight. © 2021 National Academy of Sciences. All rights reserved. 2020-12-31T15:00:00Z