2. 中國非洲豬瘟疫情持續擴散，一旦非洲豬瘟病毒進入臺灣，對國內豬肉市場和養豬業者勢必造成影響。請以非洲豬瘟入侵臺灣為前題假設，分別就此一事件對 1) 國內豬肉市場供需、數量及價格和 2) 養豬業者的產量和經濟利潤可能造成的影響，繪圖並輔以文字詳細說明。(20%)

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二、非洲豬瘟疫情

依據行政院農業委員會 106 年農業統計年報顯示，106 年國內豬肉供給量有 12.83% 來自國外進口，87.17% 由國內生產，主要豬肉進口來源國家為加拿大、西班牙、丹麥和美國，合計占總進口量的 85%，而臺灣每年從日本輸入的生鮮豬肉產品僅占進口比例約 0.06%。目前這些主要豬肉進口來源國家都不是非洲豬瘟疫區。

二、The figure below shows the essentials of a mass spectrometer, which can be used to measure the mass of an ion; an ion of mass \( m \) (to be measured) and charge \( q \) is produced in source \( S \). The initially stationary ion is accelerated by the electric field due to a potential difference \( V \). The ion leaves \( S \) and enters a separator chamber in which a uniform magnetic field \( \vec{B} \) is perpendicular to the path of the ion. A wide detector lines the bottom wall of the chamber, and the \( \vec{B} \) causes the ion to move in a semicircle and thus strike the detector. Suppose that \( B=80.000 \text{ mT} \), \( V=1000.0 \text{ V} \), and ions of charge \( q=+1.6022 \times 10^{-19} \text{C} \) strike the detector at a point that lies at \( x=1.6254 \text{ m} \). What is the mass \( m \) of the individual ions, in atomic mass units? 【Hint】： atomic mass units: \( 1 \text{ u} = 1.6605 \times 10^{-27} \text{ kg} \). The SI unit for \( \vec{B} \) : \( 1 \text{ T} = 1 \frac{\text{newton}}{(\text{coulomb/second})(\text{meter})} = 1 \frac{\text{N}}{\text{A}\cdot\text{m}} \). \( F_B = |q|vB \sin \varphi \). \( F = m \frac{v^2}{r} \).

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