게시글에 개인정보(주민등록번호, 휴대전화번호 등)가 포함되지 않도록 주의하시기 바랍니다.
http://prl.aps.org/abstract/PRL/v107/i26/e264501
Jungchul Kim1, Myoung-Woon Moon2, Kwang-Ryeol Lee2, L. Mahadevan3, and Ho-Young Kim1,*
1School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea
2Interdisciplinary and Fusion Technology Division, KIST, Seoul 136-791, Korea
3School of Engineering and Applied Sciences, Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
Writing with ink involves the supply of liquid from a pen onto a porous hydrophilic solid surface, paper. The resulting linewidth depends on the pen speed and the physicochemical properties of the ink and paper. Here we quantify the dynamics of this process using a combination of experiment and theory. Our experiments are carried out using a minimal pen, a long narrow tube that serves as a reservoir of liquid, which can write on a model of paper, a hydrophilic micropillar array. A minimal theory for the rate of wicking or spreading of the liquid is given by balancing the capillary force that drives the liquid flow and the resistance associated with flow through the porous substrate. This allows us to predict the shape of the front and the width of the line laid out by the pen, with results that are corroborated by our experiments.
기계과 김호영 교수님 방의 논문입니다. 익숙한 현상으로부터 이런 이슈를 끌어내는게 놀랍네요. 결론도 그렇고, 논리도 쉽게 와 닿는데요, 막상 논문을 보면 그다지 익숙하지 않습니다. 머랄까... 하버드 공저자와 교신저자 두분이 워낙 수학에 전문가들이네요. 특히 Prof. Mahadevan, 이 분 검색해보니 말로만 듣던 인도 수학 천재군요. 실험실 홈페이지를 가보면 자연현상을 모두 수학으로 표현하려는거 같아요.