Abstract: An axial-flow impeller includes a hub and blades. A tail edge of one blade has recessed portions successively arranged in a direction from a blade root of the blade to an outer edge of the blade. On a reference projection of the impeller on a reference plane perpendicular to a rotation axis of the impeller, a first connection line connects a starting point of a first recessed portion closest to the blade root and an end point of a second recessed portion closest to the outer edge, a second connection line connects a tail edge point of the blade root and the end point of the second recessed portion, one or more of the recessed portions is each partially located at a front-edge side of the second connection line, and remaining one or more of the recessed portions is each completely located between the first and second connection lines.

Abstract: Disclosed are a hermetic tarpaulin device and a nursing room. The hermetic tarpaulin device includes a frame and a tarpaulin body. The frame can be unfolded or folded into a predetermined shape. The tarpaulin body can be connected to the frame. When the frame is unfolded, the tarpaulin body is unfolded to form a hermetic space completely isolated from an outside world, and when the frame is folded, the tarpaulin body is folded into a whole. The tarpaulin body can be unfolded with the frame to form a hermetic space completely isolated from the outside world, which can achieve complete isolation from the outside world, thereby improving the isolation effect, and the nursing room can be more convenient to build, and can also reduce the cost and reduce the occupied space.

Abstract: Disclosed are an air intake mechanism and a negative pressure system. The air intake mechanism includes a first air intake end, a first air outlet end, and a first passage provided between the first air intake end and the first air outlet end, a first air driving unit is provided on the first passage, a first filter assembly is provided between the first air intake end and the first air driving unit, and a second filter assembly is provided between the first air outlet end and the first air driving unit.

Abstract: Disclosed is an air conditioning device, including a telescopic main structure, a ventilation air conditioning assembly and a control assembly, the ventilation air conditioning assembly is installed on the main structure, the main structure is configured to form a hermetic space inside it, and is configured to stretch or fold the hermetic space. The ventilation air conditioning assembly is configured to form a differential pressure environment in the hermetic space, the control assembly can be used to control the main structure to stretch or fold, and control the ventilation air conditioning assembly to adjust an air pressure, a temperature and a humidity in the hermetic space.

Abstract: An axial-flow impeller includes a hub and blades. A tail edge of one blade has recessed portions successively arranged in a direction from a blade root of the blade to an outer edge of the blade. On a reference projection of the impeller on a reference plane perpendicular to a rotation axis of the impeller, a first connection line connects a starting point of a first recessed portion closest to the blade root and an end point of a second recessed portion closest to the outer edge, a second connection line connects a tail edge point of the blade root and the end point of the second recessed portion, one or more of the recessed portions is each partially located at a front-edge side of the second connection line, and remaining one or more of the recessed portions is each completely located between the first and second connection lines.