Hisae O. Shimizu

Optical imaging of arteriovenous fistula for clinical application: Clarification of transillumination image of blood vessel by image-subtraction

3. Experiment and Discussion � 試作したコイルの特性を評価するため,イン ピーダンス計測実験を行った.また,比較のた め,キャパシタを挿入しない非分割コイルも2 種類試作した.1つは分割コイルと直径,コイ ル長さ,巻き数が同じで,もう一つは分割コイ ルと自己共振周波数が同程度となる,巻き数10 の非分割コイルである. リアクタンスの計測結果をFig. 4,結果のまとめ をTable 1に示す.巻き数12の非分割コイルの自 己共振周波数が156 MHzに対し,分割コイルで は179 MHzと,約15%と高い値となり,自己共 振周波数を向上することができた.また,巻き 数10の非分割コイルは自己共振周波数が185 MHzと,分割コイルと同程度の自己共振周波数 となった. 次に各コイルがMRI用マイクロコイルとして 使用可能かどうかを判断するためMRI信号受信 回路に実装し,SWR (Standing Wave Ratio) 計測 実験を行った.分割コイルのSWRは約1.2,巻き 数12の非分割コイルは約3.1となり,巻き数12の 非分割コイルはMRI用マイクロコイルとして使 用困難であるが,分割コイルは同じ巻き数であ りながら使用可能である.これは,キャパシタ 分割により自己共振周波数が向上したためであ る.なお,巻き数10の非分割コイルもSWRが約

Theoretical analysis of body hair movement in ELF electric field exposure in different environmental conditions

To elucidate the mechanism of the biological effect of ELF (extremely low frequency, 0-300 Hz) electric field and to settle appropriate safety standards, the body hair movement in AC electric field exposure was analyzed. We derived the equation of motion to describe the body hair movement cause by the electric force, and obtained an analytic solution for AC input. We applied this solution to practical conditions and clarified the body hair movement in AC electric field exposure. Using this solution, we analyzed the body hair movement in different humidity and verified the validity of the analysis in experiments.

Analysis of Body Hair Movement in ELF Electric Field Exposure

For the study of the perception of ELF electric field, a fundamental study was conducted on the movement of body hair in field exposure. The electric force exerted on a hair was given from the force component at dielectric discontinuity. With this force, the equation of the hair displacement in field exposure was derived. The displacement evaluated by the equation agreed well with experimental results. Finally, the hair movement in field exposure was formulated theoretically. The derived equation well describes the real movement of body hair in field exposure. With the equation, the mechanisms of the threshold variation in the field perception was made clear