Clinical and mechanical studies progress on treatment of malignant tumour by ultralow frequency pulsed - gradient magnetic fields 半梯度磁場治療惡性腫瘤的臨床和機理研究進展
But can keep even gradient magnetic field range strong , hall ' s component can only measurement displacement among a small circle ( usually only about 1mm ) 然而,能保持均勻梯度磁場的范圍不大,霍爾元件只能小范圍(通常僅約1mm )的測量位移。
The hore component is set on the tracking mechanical system to detect the magnetic field ' s movement . under this situation , the hore component will always keep up with the target ' s movement and keep in the magnet ' s unitary gradient magnetic field 這樣,霍爾元件慣性小、非接觸的優點將使它在各種位移與振動的測量中發揮作用,成為一種性能優良的位移傳感器。
According to more effect , when the hore component is placed in a gradient field , at the same time the direction of the current is perpendicular to the direction of the voltage , then between the two parallel side face come out the hore voltage . when hore component is set in this kind of uni - gradient magnetic field and the electric current is unchanged , the voltage output of hore component will be proportional to the position of the hore component in the magnetic field . so we can use the hore component to measure the movement of hore component against magnetic field 根據霍爾效應可知,置于磁場中的霍爾元件若電流方向與磁場方向垂直,則在霍爾元件垂直于磁場和電流方向的兩個側面將產生電勢,將霍爾元件置于強度隨空間位置線性變化的磁場中,且控制電流恒定,輸出就正比于霍爾元件處于磁場中的位置,因此可以用霍爾元件來測量磁場與霍爾元件間的相對位移量。
If we want to compose in a larger area a uni - gradient magnetic field , the device will be too complicated and unfit for move . it will restrict the application of hore component in displacement measuring . in order to change this situation , in this dissertation , a kind of auto - tracking measuring system is introduced 若能在簡單磁場的條件下,通過自動跟隨系統驅動霍爾元件跟隨測量移動物體的位移,使霍爾元件盡可能地保持在均勻梯度磁場內,就可以在很大程度上增加測量范圍。
This paper presents our research in actuating in - vivo micro - robot based on the capsule endoscope platform by the external power . while seeking secure driving method we take several factors into account , such as driving environment , power transmitting and consuming , motion requirement and controllability , and locating technique . we mainly deal with driving the capsule with spatial gradient magnetic field , so we employ combined electro - magnetic coils , including gradient coils and homogenous coils , which have rotational dof around a translatable patient bed , to compose a controllable uniform gradient which act on the permanent - magnet embedded robot , thereby get an appropriate spatial force and torque to fulfill the anticipant locomotion such as move , stop , pitch and yaw 基于驅動環境、能量供給和消耗、驅動動作要求及驅動安全性與可控性,定位方案等多方面考慮,尋求安全可靠的腸胃檢查微機器人的外部驅動控制方法,并著重研究直接利用外磁場磁力驅動微機器人:在微機器人內部嵌入永磁性體,利用體外的組合電磁線圈產生加載電流控制的驅動磁場,其中外部的電磁線圈由多組梯度線圈和勻場線圈組合構成,通過繞病床的旋轉以及病床的平移共同控制微機器人所在位置的磁場強度及梯度,作用于微機器人內嵌磁體以獲得空間意義上的必要驅動力和調整轉矩,從而有效地完成驅動動作要求。