There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

비만아 부모의 돌봄 경험: q 방법론

Self-constructing materials, which can spontaneously change their shapes from ordinary two-dimensional (2D) planes into complex three-dimensional (3D) structures, are always an attractive subject of intelligent materials. Herein, we report a simple yet effective strategy for the fabrication of programmable, thermally responsive and self-constructing hydrogels which can undergo various types of transformation from an ordinary sheet into different complex 3D shapes. By designing the surface patterns of a thermo-responsive hydrogel sheet, planar-to-tubular, planar-to-helical and planar-to-cylindrical transformation can be readily achieved upon temperature change. Integrating this kind of materials into semiconductors, self-constructive, flexible and functional electronic devices may be developed as a leading topic of smart materials.

Thermal-induced three-dimensional shape transformations of hydrogel sheets

For millennia, restoring sight to the blind has been viewed as being nothing less than miraculous. It has only been in the last few years that the fields of electronic microfabrication, neurophysiology, and retinal surgery have advanced to the point where an implantable visual prosthesis system, based on electrical stimulation, is considered feasible.

Intraocular Retinal Prostheses and Related Signal Processing

Depth perception via monocular cues was studied with a reach and grasp task in a retinal prosthesis simulator at low resolution. Results indicate that depth perception may be possible with retinal prostheses implanted only monocularly.

Retinal Prostheses: Monocular Depth Perception In the Low Resolution Limit

This paper proposes a new scan method for high frequency ultrasound (higher than 40 MHz) imaging. A needle transducer with a certain angled tip is inserted through a small incision hole and rotated around the axial direction to acquire sector or polar images of tissues deep inside the body where the conventional mechanical scanning cannot be performed. The feasibility of this novel technique was tested by computer simulation of wire phantom images and manually rotated scanning to image a polyimide tube with an unfocused 40-MHz PMN-PT needle transducer with a beveled tip of 45deg. The results indicate that the rotational scan imaging may expand the minimally invasive applications of high frequency ultrasound to other areas due to the closeness of the needle transducer to structures of interest buried in other tissues.

Mark S. Humayun

Papers

Thermal-induced three-dimensional shape transformations of hydrogel sheets

Intraocular Retinal Prostheses and Related Signal Processing

Retinal Prostheses: Monocular Depth Perception In the Low Resolution Limit

A novel scan method using angled high frequency single element needle transducers

Surgical treatment of central retinal vein occlusion