Activities

2025.08.13

I'm excited to share that our recent work, “Photophoretic flight of perforated structures in near-space conditions,” has now been published in Nature. 

We have successfully designed and fabricated a centimeter-scale ultralight panel based on a nanolattice structure, applying the principle of photophoresis to enable fuel-free, sunlight-powered levitation in low-pressure environments. This research marks a successful application of nanolattice structures outside the lab and the first-ever demonstration of levitating a centimeter-scale structure in a sunlight environment via photophoresis.

I am deeply grateful to my co–first author, Dr. Ben Schafer, and corresponding author, Prof. Joost Vlassak, with whom I have had the privilege of collaborating over the past six years. My sincere thanks also go to Prof. David Keith for guiding us in photophoresis, and to Prof. Felix Sharipov and Dr. Gyeong-Seok Hwang for their invaluable contributions.

https://seas.harvard.edu/news/2025/08/new-window-earths-upper-atmosphere
https://www.nature.com/articles/s41586-025-09281-8 

2025.07.17

Si-hyun and Jun-tae are conducting macro-scale tensile tests. They are preparing indentation and tensile data for various metallic materials, which will serve as a foundation for developing their indentation-to-tension conversion model.

2025.07.10

Our lab members took a group photo without me. lol
Please make sure to include me next time. Nice photo! :)

2025.07.10

Our lab members participated in the 2025 Industry-Academia Cooperation Forum on Secondary Batteries. They had the opportunity to introduce both our lab and their own research. Let’s keep up the great work!

2025.07.09

Dr. Sang-sub Han from KBSI visited PKNU and gave a seminar titled "Atomically Thin Wafer-Scale 2D Material Growth and Applications for Mechanically Reconfigurable Future Electronic Devices." Thank you for sharing such an exciting topic! 

2025.06.26

Prof. Kim attended the 2025 Spring Conference of the KSME Division of Materials and Fracture. After the conference, he visited Seopjikoji in Jeju Island with Prof. Gi-dong Sim, Prof. Joost Vlassak, and Prof. Jae-hoon Choi. 

2025.06.24

Prof. Vlassak and Prof. Kim visited Samsung Electronics. Many thanks to Dr. Hwang for the warm hospitality. 

2025.06.23

Prof. Vlassak and Prof. Kim visited FRONTICS, a company specializing in macro-scale indentation. We had an in-depth discussion on indentation testing with Prof. Kwon. It was a great pleasure to take a photo with my two advisors (Ph.D. and Postdoc). 

2025.06.22

Prof. Vlassak and Prof. Jiao visited the NMMRL at PKNU. We had a very productive research discussion. Sincere thanks to both for their visit.

2025.06.20

Former students and postdocs of Prof. Joost J. Vlassak from Harvard University gathered at KAIST for a workshop. It was a great pleasure to see everyone. Many thanks to Prof. Gi-dong Sim for organizing this wonderful event! 

2025.06.02-06

Prof. Kim attended ICSMA20 in Kyoto, Japan, and gave an oral presentation titled "Prediction of tensile properties from sharp indentation using neural network-based model without non-uniqueness problem." The photo was downloaded from the conference website after the event :)

2025.05.29

We ordered pizza together at the lab. Let’s all do our best in the first semester of 2025!

2025.05.13

Mr. Jinsoo Bae from Samsung Electronics visited our lab. He introduced mechanical issues related to package reliability, and we discussed how mechanical characterization techniques could contribute to improving package reliability. 

2025.04.29

Seo Hyeon's review paper submitted to JKIEEME (J. Korean Inst. Electr. Electron. Mater. Eng.) has been selected for the Best Paper Award. Congratulations, Seo Hyeon! The title of the paper is "A Review on Evaluation of Elastic Modulus Using Nanoindentation," and Si Hyun, Hyun-Wook, and Dr. Kwon from SK hynix also contributed to this work.

2025.04.23~25

Prof. Kim attended the 2025 Spring Meeting of the Korean Institute of Metals and Materials, held in Jeju island. He delivered an invited talk on the mechanical behavior of nanocardboard structures.

2025.04.15~23

Prof. Kim visited the NCBJ (National Center For Nuclear Research) in Poland to deliver an invited talk. Researchers from Seoul National University and the Korea Atomic Energy Research Institute also participated in the visit. During the stay, in-depth discussions were held with NCBJ regarding potential collaborations, and experimental plans were established. These efforts will serve as a foundation for our continued cooperation.

2025.04.01~03

NMMRL (Hyun-Wook, Seo Hyeon, Si Hyun, and Prof. Kim) participated in the 2025 Annual Conference of the Korean Microelectronics and Packaging Society (한국마이크로전자 및 패키징 학회 2025년 정기학술대회) and delivered presentations. Hyun-Wook gave a poster presentation on a study involving residual stress measurement in thin films using FIB and DIC techniques, while Prof. Kim delivered an invited talk on local residual stress measurement methods at small-scale. Great work, everyone!

2025.03.19

Prof. Jong-hyoung Kim gave a lecture at Chungnam National University on micro-mechanics-based design and applications of nanocardboard structures. Special thanks to Prof. Dong-hyun Lee for the kind invitation.

2025.03.17

NMMRL has acquired a new Macro Indentation System (FRONTICS). The new equipment features an auto-engaging function, enabling rapid indentation testing.

2025.03.17

NMMRL (Prof. Jong-hyoung Kim, Hyun-Wook Cho, and Si Hyun Park) visited Korea Institute of Materials Science (KIMS) for research meeting.

2025.01.10

NMMRL has rented a 3D surface profiler (white light interferometer) and a macro-indentation device from KIMS. These instruments will serve as a solid foundation for future collaborative research with KIMS.

2025.01.07

Prof. Jong-hyoung Kim gave an oral presentation titled "Local Mechanical Characterization at Small-scale" at NTUT in Taiwan.

2024.12.30

NMMRL had an end-of-year gathering at qooqoo.

Seo Hyeon Jang, Tae Hyeon Park and Juntae Park officially joined NMMRL. 

Welcome!

2024.12.05

Prof. Jong-hyoung Kim delivered an oral presentation titled "Prediction of Tensile Properties from Indentation Based on Neural Network-Based Model Considering Tip Geometric Imperfection" at the 7th International Conference on Materials Reliability (ICMR-2024) held in Busan. 

Additionally, Prof. Kim successfully co-organized a mini-symposium, "Innovative Material Testing and Applications in Harsh Environment," with Prof. Jin-Ha Hwang (PKNU).

2024.12.04

During ICMR-2024, Prof. Jong-hyoung Kim had dinner with Dr. Kunio Hasegawa (JAEA), Prof. Namsu Huh (SeoulTech), and Prof. Dongil Kwon (SNU). The beef was fantastic!

2024.11.01

Si Hyun Park & Hyun Wook Cho have joined NMMRL as undergraduate researchers.
A warm welcome to both of them!

2024.10.28

Prof. Jong-hyoung Kim delivered an oral presentation titled "Stress-Corrosion Cracking of Polypropylene in Harsh Oxidizing Environments" at the 2024 Fall Meeting of the Korean Institute of Metals and Materials (2024 대한금속재료학회 추계학술대회) held in Pyeongchang in South Korea. He also served as the session chair for the Mechanics and Measurement division.

2024.09.13

Prof. Seung-Kyun Kang (SNU) and Dr. Jae-Young Bae (SNU) visited NMMRL! We had an in-depth discussion about the direction of future collaborative research. Welcome!

2024.08.29

Prof. Jong-hyoung Kim delivered an oral presentation titled "2D Nanolattice Structure: Mechanical Behavior & Application for Levitating" at the 2024 Advanced Strcutural Materials Symposium (2024 첨단구조재료심포지엄) held in Gyeongju.