Abstract: A supported metallocene catalyst includes a carrier and a metallocene component. The carrier includes an inorganic oxide particle and an alkyl aluminoxane material. The inorganic oxide particle includes at least one inorganic oxide compound selected from the group consisting of an oxide of Group 3A and an oxide of Group 4A. The alkyl aluminoxane material includes an alkyl aluminoxane compound and an alkyl aluminum compound that is present in amount ranging from greater than 0.01 wt % to less than 14 wt % base on 100 wt % of the alkyl aluminoxane material. The metallocene component is supported on the carrier, and includes one of a metallocene compound containing a metal from Group 3B, a metallocene compound containing a metal from Group 4B, and a combination thereof. A method for preparing the supported metallocene catalyst and a method for preparing polyolefin using the supported metallocene catalyst are also disclosed.

Abstract: A tractor assembly includes a connection unit which is connected between the tractor and the wheel chair. The connection unit includes a fixing member, a top link unit, a bottom link unit and a swing rod so as to form a four-link mechanism. The connection unit includes an engaging unit with an engaging section, and a position unit. The top link unit has a reception hole and the positioning unit has a push rod. When the push rod is located at the first position, the reception hole is closed. When the push rod is located at the second position, the push rod is retracted and the reception hole is exposed. The bottom link unit is pivoted about one end of the swing rod to move the other end of the swing rod to the position of the reception hole, the engaging section is inserted into the reception hole.

Abstract: A tractor assembly includes a connection unit which is connected between the tractor and the wheel chair. The connection unit includes a fixing member, a top link unit, a bottom link unit and a swing rod so as to form a four-link mechanism. The connection unit includes an engaging unit with an engaging section, and a position unit. The top link unit has a reception hole and the positioning unit has a push rod. When the push rod is located at the first position, the reception hole is closed. When the push rod is located at the second position, the push rod is retracted and the reception hole is exposed. The bottom link unit is pivoted about one end of the swing rod to move the other end of the swing rod to the position of the reception hole, the engaging section is inserted into the reception hole.