Abstract: Methods, systems, and computer programs are presented for eliminating bias while training an ML model using training data that includes past experimental data. One method includes accessing experiment results, for A/B testing of a first model, that comprise information regarding engagement with a first set of items presented to users, each item being presented within an ordered list of results. A position bias is calculated for positions within the ordered list of results where the items were presented. A machine-learning program is trained to obtain a second model using a training set comprising values for features that include the calculated position bias. The method includes detecting a second set of items to be ranked for presentation to a first user, and calculates, using the second model, a relevance score for the second set of items, which are ranked based on the respective relevance score and presented on a display.

Abstract: An exercise apparatus and a method thereof relate to the technical fields of physical exercise, training instruments, life cultivation and health preservation, leisure and entertainment, teaching appliances, smart home and the like. Through reverse thinking, by changing a shape, a structure, a function, a control method or/and a using method of an electric scooter, the electric scooter is switched to the fields of physical exercise or/and learning and education. By means of technical characteristics in an attempt to avoid by the technical staff, unexpected technical effects are achieved, and a new purpose of the electric scooter is achieved. The exercise apparatus carries a user to perform automatic round-trip movement, the user correspondingly adjusts physical and mental states to prevent from falling and the exercise apparatus is helpful for improving abilities of balancing, coordination, relaxation, flexibility, concentration and contingency of the user.

Abstract: An N-type double-sided solar cell preparation method comprises: sequentially forming a front aluminum oxide passivation layer and a front silicon nitride anti-reflection layer on a front face of an N-type silicon wafer. The front aluminum oxide passivation layer is prepared by using a plasma-enhanced atomic layer deposition method, and the deposition conditions thereof involve: any frequency in the frequency range of 40 kHz to 400 kHz is selected to be a radio-frequency power supply frequency, a gaseous aluminum source is first introduced into a plasma apparatus in a vacuum state, such that a layer of aluminum source molecules is adsorbed on the surface of the silicon wafer, and a gaseous oxygen source is then introduced, such that the oxygen source is ionized into plasma and reacts with the aluminum source to obtain aluminum oxide.

Abstract: A method for manufacturing a TOPCon cell includes following steps: texturing a front side of an silicon wafer and then preparing a PN junction; forming a tunnel oxide layer, an intrinsic polysilicon layer, a doped polysilicon layer, and a silicon oxide mask layer in sequence on a back side of the silicon wafer, wherein the tunnel oxide layer is deposited by PEALD at a deposition temperature of 150° C. to 200° C., the doped polysilicon layer is deposited by PECVD, and the silicon oxide mask layer has a thickness of 10 nm to 40 nm; removing a wraparound silicon oxide mask layer material and a wraparound polysilicon layer material from the front side of the silicon wafer, and then removing the silicon oxide mask layer from the back side; and forming a front electrode on the PN junction and a back electrode on the doped polysilicon layer, respectively.

Abstract: In the preparation process for a passivated contact battery, preparation of a back surface field passivation structure thereof comprises: growing a tunneling oxide layer on a back surface of a silicon wafer; growing an intrinsic silicon carbide layer on a surface of the tunneling oxide layer; growing a phosphorus-doped silicon carbide layer on a surface of the intrinsic silicon carbide layer; and performing annealing, so as to cause the silicon carbide and the phosphorus in the phosphorus-doped silicon carbide layer to form covalent bonds. The passivated contact battery can be obtained by means of the described preparation process, and same comprises a silicon wafer as well as a tunneling oxide layer, an intrinsic silicon carbide layer, and a phosphorus-doped silicon carbide layer which are sequentially stacked on a back surface of the silicon wafer.

Abstract: A silicon oxide layer is formed on the back surface of an N-type silicon wafer; an N-type silicon layer is formed on the silicon oxide layer, wherein the phosphine concentration of the N-type silicon layer is within a first preset concentration range; and an antireflection layer is formed on the N-type silicon layer and a back electrode is formed on the antireflection layer. In the high-temperature annealing process, hydrogen atoms can be bound by phosphine, such that membrane explosion caused by the escape of hydrogen atoms is avoided, an open-circuit voltage, the conversion efficiency and a filling factor can be improved, a back passivation effect can be enhanced, and the quality of a cell piece can be improved.

Abstract: In a solar cell, the back surface of a substrate thereof is provided with alternately distributed emitter zones and back surface field zones. An emitter is formed in each emitter zone, and the emitters are made of boron-doped monocrystalline silicon. A back surface field is formed in each back surface field zone; the back surface fields comprise tunneling oxide layers and polycrystalline silicon layers in stacked distribution, the polycrystalline silicon layers being made of phosphorus-doped polycrystalline silicon, and the tunneling oxide layers being located between a polycrystalline silicon layer and a polycrystalline silicon layer. Positive electrodes are electrically connected to the emitters, and negative electrodes are electrically connected to the back surface fields.

Abstract: Methods, systems, and computer programs are presented for eliminating bias while training an ML model using training data that includes past experimental data. One method includes accessing experiment results, for A/B testing of a first model, that comprise information regarding engagement with a first set of items presented to users, each item being presented within an ordered list of results. A position bias is calculated for positions within the ordered list of results where the items were presented. A machine-learning program is trained to obtain a second model using a training set comprising values for features that include the calculated position bias. The method includes detecting a second set of items to be ranked for presentation to a first user, and calculates, using the second model, a relevance score for the second set of items, which are ranked based on the respective relevance score and presented on a display.

Abstract: A tunnel oxide layer, an N-type bifacial crystalline silicon solar cell and a method for manufacturing the same are provided. The method for manufacturing the tunnel oxide layer includes forming excess -OH on a back side of a silicon wafer, and depositing the tunnel oxide layer on the back side of the silicon wafer by a Plasma Enhanced Atomic Layer Deposition method. The method for manufacturing the N-type bifacial crystalline silicon solar cell can include following steps: performing cleaning, texturing, boron diffusing, and alkaline polishing on an N-type silicon wafer, sequentially forming a P-type doped layer, a passivation layer, and an anti-reflection layer on a front side of the alkaline-polished N-type silicon wafer, and forming a tunnel oxide layer on a back side of the alkaline-polished N-type silicon wafer, followed by forming an N-type doped polysilicon layer, and after annealing, forming an anti-reflection layer.

Abstract: The present invention discloses an isolation section suppressing shock wave forward transmission structure for a wave rotor combustor and a wave rotor combustor, and belongs to the new concept field of unsteady combustion. The isolation section suppressing shock wave forward transmission structure for a wave rotor combustor includes a wave rotor and a gas inlet port, and the wave rotor is provided with several wave rotor channels. When the wave rotor rotates, the several wave rotor channels communicate with the isolation section sleeve sequentially through the fan-shaped hole. The present invention suppresses reflected shock waves by changing a flow blockage ratio and a shape of the pneumatic valve to consume back transmission pressure, which is beneficial to a fuel intake process, so that steady working of the wave rotor combustor in a state of deviating from a design point can be implemented.

Abstract: The present invention discloses an isolation section suppressing shock wave forward transmission structure for a wave rotor combustor and a wave rotor combustor, and belongs to the new concept field of unsteady combustion. The isolation section suppressing shock wave forward transmission structure for a wave rotor combustor includes a wave rotor and a gas inlet port, and the wave rotor is provided with several wave rotor channels. When the wave rotor rotates, the several wave rotor channels communicate with the isolation section sleeve sequentially through the fan-shaped hole. The present invention suppresses reflected shock waves by changing a flow blockage ratio and a shape of the pneumatic valve to consume back transmission pressure, which is beneficial to a fuel intake process, so that steady working of the wave rotor combustor in a state of deviating from a design point can be implemented.

Abstract: An exercise apparatus and a method thereof relate to the technical fields of physical exercise, training instruments, life cultivation and health preservation, leisure and entertainment, teaching appliances, smart home and the like. Through reverse thinking, by changing a shape, a structure, a function, a control method or/and a using method of an electric scooter, the electric scooter is switched to the fields of physical exercise or/and learning and education. By means of technical characteristics in an attempt to avoid by the technical staff, unexpected technical effects are achieved, and a new purpose of the electric scooter is achieved. The exercise apparatus carries a user to perform automatic round-trip movement, the user correspondingly adjusts physical and mental states to prevent from falling and the exercise apparatus is helpful for improving abilities of balancing, coordination, relaxation, flexibility, concentration and contingency of the user.

Abstract: A synthesis method of ?-nitropyrazole amide compound through asymmetrical catalyzing technique is provided, a nitroalkane and an ?,?-unsaturated pyrazole amide are applied as the raw material, a complex formed by a chiral amine oxide with a rare earth metal compound is served as the catalyst, a 4 ? molecular sieve is served as an additive, the ?-nitropyrazole amide compound can be obtained with a yield more than 99% and enantiomeric excess more than 99% ee. The catalytic system not only has the advantages of simple operation, mild reaction conditions, requiring no acid/base additives, convenient product purification, high yield and enatioselectivity, compliance with green atomic economy, and promising prospects for industrial application, but also allows the obtained ?-nitropyrazole amide compound to undergo some simple chemical conversions to produce some molecules having physiological activities.

Abstract: Provided is a method for preparing a nitrogen-containing aromatic compound through catalytic pyrolysis from organic materials. The method comprises: feeding organic materials and a catalyst into a reactor, to enable the organic material to undergo reactions in the presence of nitrogen and under heating conditions, so as to generate a reaction system flow containing one or more nitrogen-containing aromatic compounds.

Abstract: A paroxetine intermediate, a method for preparing the same, and uses thereof are provided. Specifically, the method includes: reacting a compound of formula I below with a compound of formula II in the presence of an organic base under the catalysis of a complex formed from a chiral amine oxide L and a rare-earth metal compound Ln(OTf)3 to prepare a compound of formula III below: wherein R1 is alkyl, phenyl or benzyl; R2, R3, R4 are each independently C1-C6 alkyl or C6-C10 aryl; the chiral amine oxide L has the following structure: wherein n=1, 2; and R=Ph—, 2,6—Me2C6H3—, 2,6—Et2C6H3—, 2,6-iPr2C6H3—, Ph2CH—.

Abstract: A synthesis method of ?-nitropyrazole amide compound through asymmetrical catalyzing technique is provided, a nitroalkane and an ?,?-unsaturated pyrazole amide are applied as the raw material, a complex formed by a chiral amine oxide with a rare earth metal compound is served as the catalyst, a 4 ? molecular sieve is served as an additive, the ?-nitropyrazole amide compound can be obtained with a yield more than 99% and enantiomeric excess more than 99% ee. The catalytic system not only has the advantages of simple operation, mild reaction conditions, requiring no acid/base additives, convenient product purification, high yield and enatioselectivity, compliance with green atomic economy, and promising prospects for industrial application, but also allows the obtained ?-nitropyrazole amide compound to undergo some simple chemical conversions to produce some molecules having physiological activities.

Abstract: A paroxetine intermediate, a method for preparing the same, and uses thereof are provided. Specifically, the method includes: reacting a compound of formula I below with a compound of formula II in the presence of air organic base under the catalysis of a complex formed from a chiral amine oxide L and a rare-earth metal compound Ln(OTf)3 to prepare a compound of formula III below: wherein R1 is alkyl, phenyl or benzyl; R2, R3, R4 are each independently C1-C6 alkyl or C6-C10 aryl; the chiral amine oxide L has the following structure: wherein n=1, 2; and R=Ph-, 2,6-Me2C6H3-, 2,6-Et2C6H3-, 2,6-iPr2C6H3-, Ph2CH—.

Abstract: Provided is a method for preparing a nitrogen-containing aromatic compound through catalytic pyrolysis from organic materials. The method comprises: feeding organic materials and a catalyst into a reactor, to enable the organic material to undergo reactions in the presence of nitrogen and under heating conditions, so as to generate a reaction system flow containing one or more nitrogen-containing aromatic compounds.

Abstract: A system communicating over a full duplex control channel of a multimedia communication link by using synchronization signals that may also function as a logical link command. Synchronization indicators are exchanged between two communicating devices for maintaining synchronization of a logical link. At least two different types of synchronization signals may be sent between the two devices as synchronization indicators. A first synchronization signal is used by default to maintain synchronization of a logical link. A second synchronization signal is used in place of the first synchronization signal to maintain synchronization of the logical link. The second synchronization signal may be used to imply a virtual link command to indicate that a device is ready to receive data or has successfully received data over the virtual link.