Abstract: An air conditioning unit includes: a first refrigeration system including a first evaporator, a first compressor, a first condenser, a first one-way valve, and a first throttling element connected in sequence in a loop as well as a second one-way valve connected in parallel with the first compressor, and a first fluorine pump connected in parallel with the first one-way valve; and a second refrigeration system including a second evaporator, a second compressor, a second condenser, a third one-way valve, and a second throttling element connected in sequence in a loop as well as a fourth one-way valve connected in parallel with the second compressor, and a second fluorine pump connected in parallel with the third one-way valve, where the first evaporator and the second evaporator are arranged front and rear in sequence along a return air cooling duct.

Abstract: A large-width cathode roller for producing high-strength ultra-thin copper foil includes titanium side plates and a titanium cylinder sealed by the titanium side plates, and a cathode roller core penetrated through the titanium side plates. Steel-copper explosive clad cylinders and a steel support plate are disposed in/on the side plate, inner ring surfaces of the side plates and the copper plates are connected to a copper sleeve around the cathode roller core, outer ring surfaces of the copper plates and the steel support plates are connected to a copper cylinder, inner ring surfaces of the steel support plates are connected to the cathode roller core; and multiple electrically conductive support rings on the copper cylinder are connected to the copper plates on two sides through the electrically conductive copper bars to form a conducting loop to improve the distribution uniformity of the current on the surface of the cathode roller.

Abstract: The present invention discloses construction method and system of a descriptive model of classroom teaching behavior events. The construction method includes steps as the followings: acquiring classroom teaching video data to be trained; dividing the classroom teaching video data to be trained into multiple events according to utterances of a teacher by using a voice activity detection technology; and performing multi-modal recognition on all events by using multiple artificial intelligence technologies to divide the events into sub-events in multiple dimensions, establishing an event descriptive model according to the sub-events, and describing various teaching behavior events of the teacher in a classroom. The present invention divides a classroom video according to voice, which can ensure the completeness of the teacher's non-verbal behavior in each event to the greatest extent.

Abstract: A hot-spinning formation method for large-diameter titanium alloy cylindrical parts. A workblank is placed in a resistance furnace to heated to 600-650° C., is maintained at this temperature for 0.5-1 h and is then taken out of the resistance furnace; after the workblank is heated, the inner diameter of the workblank becomes larger; the heated workblank is installed on a mandrel, and spinning is started when a maximum clearance between the workblank and the mandrel is less than 0.5 mm; the mandrel and the spinning rollers do not need to be preheated, and a multi-pass spinning process is adopted, such that the workblank can deform more uniformly. A vertical spinning lathe is used for spinning, the mandrel is easy to change, and the workblank is easy to assemble and disassemble.

Abstract: A large-width cathode roller for producing high-strength ultra-thin copper foil includes titanium side plates and a titanium cylinder sealed by the titanium side plates, and a cathode roller core penetrated through the titanium side plates. Steel-copper explosive clad cylinders and a steel support plate are disposed in/on the side plate, inner ring surfaces of the side plates and the copper plates are connected to a copper sleeve around the cathode roller core, outer ring surfaces of the copper plates and the steel support plates are connected to a copper cylinder, inner ring surfaces of the steel support plates are connected to the cathode roller core; and multiple electrically conductive support rings on the copper cylinder are connected to the copper plates on two sides through the electrically conductive copper bars to form a conducting loop to improve the distribution uniformity of the current on the surface of the cathode roller.

Abstract: A hot-spinning formation method for large-diameter titanium alloy cylindrical parts. A workblank is placed in a resistance furnace to heated to 600-650° C., is maintained at this temperature for 0.5-1 h and is then taken out of the resistance furnace; after the workblank is heated, the inner diameter of the workblank becomes larger; the heated workblank is installed on a mandrel, and spinning is started when a maximum clearance between the workblank and the mandrel is less than 0.5 mm; the mandrel and the spinning rollers do not need to be preheated, and a multi-pass spinning process is adopted, such that the workblank can deform more uniformly. A vertical spinning lathe is used for spinning, the mandrel is easy to change, and the workblank is easy to assemble and disassemble.

Abstract: The disclosure discloses a fingerprint positioning method in a smart classroom, which is specifically: firstly, performing Gaussian filtering and taking the average value on a wireless signal strength value RSSI in the fingerprint database; then finding the neighbor point closest to the signal strength of the to-be-measured point; finally, the Euclidean distance is used as the weight reference, and the weighted center of mass is obtained for the nearest neighbor points. The weight index is introduced as an index of the weight, and the coordinates of the to-be-tested node are obtained. The disclosure has a higher positioning accuracy, smaller positioning error fluctuations and greater environmental adaptability.

Abstract: The disclosure discloses a fingerprint positioning method in a smart classroom, which is specifically: firstly, performing Gaussian filtering and taking the average value on a wireless signal strength value RSSI in the fingerprint database; then finding the neighbor point closest to the signal strength of the to-be-measured point; finally, the Euclidean distance is used as the weight reference, and the weighted center of mass is obtained for the nearest neighbor points. The weight index is introduced as an index of the weight, and the coordinates of the to-be-tested node are obtained. The disclosure has a higher positioning accuracy, smaller positioning error fluctuations and greater environmental adaptability.