臺灣博碩士論文加值系統

為了探討應變速率對足底軟組織機械特性的影響，5-12MHz的超音波探頭以三個不同的最大負載速度3.75±0.2cm/s、6.23±0.4 cm/s、14.64±0.2cm/s，直接在足底軟組之上施19.6N/cm2的應力。記錄足底軟組織在動態受力下的厚度變化。
實驗的對象皆為足底正常的年輕人，共有5位女性及7位男性，平均年齡為25±2.4歲。實驗所得結果壓縮指標（compressive index：CI）、勁度（stiffness：Ep）以及能量散逸率（energy dissipation of ratio：EDR）等參數變化作為軟組織機械特性的指標。負載速度的變化會明顯地影響軟組織遲滯圈的負載相走勢，負載速度越高遲滯圈負載相越往上移。而卸載相是不會受到壓縮頻率而變化的。這現象會直接反映在EDR值的變化上頭。前足部的EDR值對應於三個頻率分別38.29±9.07%、43.42±8.31%及54.59±7.44%; 在後足部則為32.56±3.89%、36.08±6.04%及49.65±5.65%。EDR有明顯地因頻率而升高的現象。在CI方面，在本實驗的速度範圍內，不會受到負載速度改變的影響。前足除第一趾（61.78±2.73％）外的四趾（55.26±6.28％）有近似相同的數值。第一趾會稍大。後足部的CI（45.68±6.98％）則是比前足部小。Ep則和負載速度沒有直接的關連。
本實驗雖然無法真正模擬走路的負載速度，卻充分地說明負載速度的改變對EDR的影響，以及軟組織特性如何改變。軟組織遲滯圈曲線配合再上CI與EDR等參數，可以發現前足與後足因為構造上的不同，而有機械特性上的差異。

Loading-unloading apparatus that combined clinical ultrasound and load cell was built to investigate the effects of strain rate on the plantar soft tissue. A 5-12 MHZ linear array transducer was used to compress the soft tissues up to 19.6N/cm2, and three loading velocities 3.75±0.2cm/s, 6.23±0.4cm/s, 14.64±0.2cm/s was adopted. The changes in soft-tissue thickness and the compression force were recorded simultaneously, and the stress-strain could be derived directly.
Young subjects (five females and seven males) with no apparent foot diseases were enrolled in the study. The mechanical properties were based on their compressive index (CI), stiffness (Ep), and energy dissipation of ratio (EDR). For young subjects, the increase in loading velocity caused the stress-strain curve at the loading phase to shift upward. However, the unloading phase was not affected. This resulted an increase in the EDR. The EDR for fore foot (metatarsal heads) were about 38.29±9.07%, 43.42±8.31% and 54.59±7.44% that corresponding to increasing frequencies. The EDR for the heel pad were 32.56±3.89%, 36.08±6.04% and 49.65±5.65% respectively. Higher strain rate resulted in a larger EDR. The loading velocity had little influence on the CI. The metatarsal heads of the fore foot except the first toe (61.78±2.73%) have similar CI values (55.26 ±6.28%). The CI of the heel pad is smaller than that of the fore foot. No direct correlation was found between the Ep and the loading velocity.

英文摘要…………………………………………….…………………Ⅰ
摘要…………………………………………….……………………….Ⅱ
目錄……………………………………………………………………..Ⅲ
表目錄…………………………………………………………………..Ⅴ
圖目錄………………………………………………………………..…Ⅵ
第一章緒論……………………………………………………………1
1-1前言……………………………………………………………...1
1-2文獻回顧………………………………………………………1
1-3研究動機與目的………………………………………………...3
1-4論文架構………………………………………………………...4
第二章研究原理………………………………………………………..5
2-1材料力學理論………………………………………………...…5
2-2生物體的黏彈特性……………………………………...………6
2-3足底構造………………………………………………………9
2-2-1後足構造…………………………………………………...9
2-2-2前足構造………………………………………….10
2-4醫用超音波基本原理……………………………………….…10
第三章實驗方法與步驟………………………………………………12
3-1實驗方法…………………………………………………….…12
3-1.1力量的施予………………………………………………..12
3-1.2軟組織厚度變化…………………………………………..13
3-1.3下壓速度的設計…………………………………………..13
3-2實驗設備…………………………………………………….…13
3-3實驗步驟…………………………………………………….…15
3-3-1荷重轉換器校正……………...………………………..…15
3-3-2力與位移同步校正………………...…………………..…15
3-4實驗對象…………………………………………………….…16
3-5實驗步驟…………………………………………………….…16
3-6資料的分析與處理………………………………………….…18
第四章結果與討論………………………………………………19
4-1實驗結果……………………………………………..…19
4-1-1軟組織勁度與力量大小關係………………..………...…19
4-1-2軟組織勁度與壓縮頻率的關係………………………….19
4-1-3軟組織應力與應變的關係……………………………..20
4-1-4EDR與頻率的關係………………………………………20
4-1-5EDR與測量點的關係…………………………………20
4-1-6CI與Ep………………………………………………….21
4-2實驗討論……………………………………………………….20
4-2-1誤差分析………………………………………………….21
4-2-2軟組織的機械特性與壓縮頻率的關係……………….…23
4-2-3前足部與後足部的比較…….……………………………25
4-2-4同一個量測點下，EDR在個體中的差異………………..26
4-2-5可信度………………………………………………….…27
4-2-6實驗結果與文獻比較……………………………………28
4-2-7改變施力頻率的意義…………………………………….30
4-2-8水袋的影響與預先調節的意義…………………………30
4-2-9最大應力的比較…………………………………………31
4-2-10吸震能力的探討…………………………………………31
第五章結論……………………………………………………………32
參考文獻………………………………………………………………..34

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