Abstract: A photodetector includes a first semiconductor layer, an absorption structure, a second semiconductor layer, and a barrier structure. The absorption structure is located on the first semiconductor layer, and having a first conduction band, a first valence band, and a first band gap. The second semiconductor layer is located on the absorption structure, and having a second conduction band, a second valence band, and a second band gap. The barrier structure is located between the absorption structure and the second semiconductor layer, and having a third conduction band, a third valence band, and a third band gap. The third conduction band is greater than the second conduction band or the third valence band is less than the second valence band.

Abstract: A folding bicycle includes an X-shaped frame consisting of a lower front, a lower rear, an upper front, and an upper rear supporting arm; a front and a rear wheel respectively mounted to distal ends of the lower front and lower rear supporting arms; a saddle pivotally connected to a distal end of the upper rear supporting arm; a handlebar rotatably connected to a distal end of the upper front supporting arm; a locking mechanism mounted between the lower front and lower rear supporting arms for holding the frame in an extended position; and a steering mechanism arranged between the handlebar and the front wheel for steering the bicycle.

Abstract: The present invention provides an aerobic exercise device, which has contour of a nunchaku, comprising a pair of rubber holding rods having a receiving hole respectively, a pair of spheroidal revolvers located in said receiving holes respectively, and at least an elastic rope made by latex material being coupled with said revolvers by two ends thereof. The aerobic exercise device provided by this invention can have safer function when practicing because of its design.

Abstract: A push-up exercise holder. The holder includes a seat, a lever that is pivotally installed on the holder, and an elastic buffer element is installed between the seat and the lever. A holding portion of the lever is elevated and positioned on the seat, and a notch is formed between the lever and seat so that as the push-up exercise holder is held, it generates a buffer effect with upward and downward movement of a body.

Abstract: A multipurpose exerciser is provided that is formed from two pivotally connected n-shaped frames and an adjustable crossbar extending between one of the n-shaped frames near two ends thereof. Foam rubber material is wrapped around the two n-shaped frames and the adjustable crossbar. One of the n-shaped frames is a primary frame which has a middle portion forming a handle for a user to grip. The adjustable crossbar is provided with two loop-shaped straps at the two outer ends thereof for putting over different areas of the user's body for safety purposes. The two n-shaped frames are angularly adjustable relative to each other, to permit the user to do different exercises with the exerciser by applying force to the primary frame. The exerciser can be used for abdominal exercises, rowing exercises, chest and arm exercises, etc.