In this presentation, numerical study on crack location and crack number on the responses of representative unit cell of unidirectional composites under tension is conducted by extended finite element method (XFEM). The composites studied here are single-crack composites, two-crack composites, and three-crack composites. Each of the composites is under tension in the x direction, in the y direction, and in the z direction. Basing on simulation results, one can draw conclusion that the averaged strength decreases as the embedded crack number increases when composites are under tension. One interesting finding is that a crack could be a dominant crack but becomes inactive when other different cracks are in presence under the same loads. The responses of representative unit cell of composites depend upon crack location and the applied loading direction. The results from these simulations can also explain why there is discrepancy of strength prediction from the composites manufactured under the same conditions. The simulation method presented here can be
used to model degree of defects (by modelling the number of cracks) and stochastic characteristics of ultimate strength (by modelling distribution of crack strength)

本研究主要利用熱電偶感測器及布拉格光纖光柵感測技術，探討不同纖維疊層數下乙烯基樹脂搭配玻璃纖維在製成複合材料積層板時，成型時產生的溫度與成型後積層板內部的殘留應變的關聯。乙烯基樹脂為船舶產業中常用的樹脂種類，具有極佳的機械性及耐候性，但在固化交聯時會劇烈放熱，導致成型後製品內部存在殘留應變並產生尺寸收縮，本研究進行多組實驗並逐漸增加纖維層數，觀測樹脂硬化過程中布拉格光纖光柵之波長漂移的情形並測量各層的溫度變化，來分析積層板由開始灌注到固化結束的內部情形，隨後藉由相關公式計算固化結束後之殘留應變，並在對積層板進行後硬化處理後，再次量測波長位置最終獲得各層數之殘留應變。最後結果得出當纖維層數及樹脂量增加時積層板內部之層間殘留應變也會隨之增加，其增加的幅度並非以線性上升，而是指數性的隨著層數增長，另外底層(靠近模具面)的溫度低於其他各層的溫度，說明不同模具材質會影響樹脂放熱。

我們外加雙頂閘極於砷化銦為基材的二維電子氣分離式閘極元件。分離式閘極侷限了電子傳輸方向只能在x方向；頂閘極則是在電子傳輸方向形成位障。而我們探討由內建電場所引起的Rashba效應、因塊材反轉不對稱，引發等效內建電場的Dresselhaus效應、及對分離式元件施加磁場所造成的Zeeman效應的作用下，對電導的影響。我們報告了在固定閘極長度與寬度，且固定Rashba效應及Zeeman效應參數，僅改變Dresselhaus效應強度參數，發現了RP結構與HBS均會受到Dresselhaus效應的影響而改變，而RP結構並未消失；隨著Dresselhaus參數β值越大，RP能量出現紅移現象。內模態分電導G22在β值大於0.1時開始貢獻；並且β值越大，貢獻越明顯；β值在0.15時我們發現量子點HBS。
------
We apply a double-top-gate to a split-gate device in a InAs-based 2DEG. The split-gate limits the electron transmission direction to only the x direction; the top gate forms a barrier in the electron transmission direction. And we discuss the Rashba effect caused by the build-in electric field, the Dresselhaus effect that causes the equivalent build-in electric field due to the asymmetry of the bulk material, and the Zeeman effect caused by the application of a magnetic field to the separate element. We report that when the length and width of the gate are fixed, and the Rashba effect and Zeeman effect parameters are fixed, only the Dresselhaus effect strength parameters are changed. We found that both the RP structure and HBS will be affected by the Dresselhaus effect and change, but the RP structure has not disappeared; as the value of β increases, the energy decreases, and a red shift occurs. The partial conductance G22 starts to make a contribution when the β value is greater than 0.1, and the larger the β value, the more obvious the contribution. When the β value is 0.15, we find the quantum dot HBS.

我們探討具雙指閘的P型磁控窄通道半導體元件，因為指閘極電壓的變化以及磁控產生的Zeeman效應，對電洞的電導結構影響。若隨著雙指閘系統中每一指閘施加的電位能上升，會將電導結構逐漸往下壓，電導結構從理想的電導結構，慢慢轉變成共振峰結構，最後變為類似無限深位能井的結構，而藉由無限深位能井的關係，我們就可以使用推算出來的公式，預測出輕重電洞各自共振峰出現的能量點位置。當我們再加入磁控產生的Zeeman效應，可以清楚的看到Zeeman效應導致的電導分裂在低能量區比在高能量區明顯。
---------
We discuss the P-type magnetic-field controlled narrow channel with double-finger gate components, because the change of finger gate voltage and the Zeeman effect produced by the magnetic field affect the conductance structure of the hole. If the potential energy applied by each finger gate in the two-finger gate system rises, the conductance structure will gradually be pressed down, and the conductance structure will gradually change from an ideal conductance structure to a resonance peak structure, and finally become similar infinite deep potential energy well. By the structure of infinitely deep potential energy well, we can use the calculated formula to predict the position of the energy point where the each resonant peak of the light and heavy electric holes appear. When we add the Zeeman effect produced by the magnetic field, we can clearly see that the conductance splitting caused by the Zeeman effect is more pronounced in the low-energy region than in the high-energy regime.

In 1934, Timoshenko presented the solution of the deformation of an isotropic rectangular bar under torsion. A truth cannot be ignored is that the deformation of a rectangular bar under torsion should remain the same if the values of its thickness and width are exchanged. Timoshenko’s solution does not fit this truth and is obviously an approximation. The solution of the deformation of an orthotropic bar under torsion was presented in 1950 by Lekhnitski, which is in series form and energy conservation is not taken into consideration. In 1990, Tsai, Daniel and Yaniv presented a close form solution of the deformation of an orthotropic plate under torsion taking into consideration its out-off-plane behavior and energy conservation. By applying a shear correction factor for correcting the strain energy induced by the shear stress to equal to the work done by the external torsion. This work seems to be the only one dealing with an anisotropic plate under torsion in the 30 years after Lekhnitski’s work, and the solutions of both works are extremely identical numerically. However, when the thickness of the plate is in the same order as that of its width, the plate is no more a “thick plate”, but a rod. The behavior in out-off-plane direction is no more a sidekick of the in-plane behavior, and Tsai’s assumption is no more suitable. This work presents, 30 years after Tsai’s research, an exact solution of the deformation of an orthotropic rod under torsion. Fourier series is applied, and all the stresses and strains are derived. All the compatibility conditions, stress boundary conditions, stress equilibrium conditions, force equilibrium condition and energy conservation condition are all taken into consideration and satisfied. When the solution is simplified for isotropic rectangular bar, it is extremely close to Timoshenko’s approximate solution numerically until the aspect ratio is larger than 5.

A low-cost tactile sensor has been developed by using a thin coating of polyvinyl alcohol (PVA) doped with Iron (Fe) particles over an Indium Tin Oxide (ITO) coated polyethylene terephthalate (PET) substrate. Fe-PVA composite film was face-to-face assembled with PET-ITO to form a tactile sensor. The electrical contact resistance (ECR) variation has been monitored for experimental and practical tactile sensing application. A highest sensitivity of 1.96 kPa-1 has been achieved. Further, real-time applications in fist-clenching detection were successfully carried out showing the great potential for wearable applications.