Abstract: A positive electrode active material, a positive electrode plate, a secondary battery, and a power consuming apparatus are provided. The positive electrode active material includes (i) secondary particles and (ii) single-crystal or quasi-single-crystal particles. The secondary particles are mainly formed by aggregating primary particles and the secondary particles further include an M1 element. The M1 element includes a transition metal element other than iron. A mass content of the M1 element is X1 based on a total mass of the secondary particles, where 500 ppm?X1?5000 ppm, and optionally, 800 ppm?X1?2000 ppm. The single-crystal or quasi-single-crystal particles include an Ma element. The Ma element includes a transition metal element other than iron. A mass content of the Ma element is X2 based on a total mass of the single-crystal or quasi-single-crystal particles, where X2 is less than X1.

Abstract: An electrode sheet, a secondary battery, an electric device, a preparation method, and a reuse method are described. The electrode sheet comprises a current collector and multiple active material layers located on at least one side of the current collector; the multiple active material layers comprise a first active material layer and a second active material layer, wherein the second active material layer is the active material layer farthest from the current collector, and the first active material layer is located between the second active material layer and the current collector, and comprises current collector particles.

Abstract: The present disclosure relates to a lithium-ion secondary battery, a battery apparatus, an electrical apparatus, and preparation methods for a positive electrode active material and a positive electrode plate. The battery includes a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate comprises a current collector and a film layer disposed on at least one side of the collector. The film layer comprises a positive electrode active material including lithium-containing transition metal phosphate particles, at least part of the surfaces of which are coated with a carbon material. In a cross-section along the electrode plate thickness direction, the DA90 of the particles ranges from 1400 nm to 2100 nm, and the particle size concentration ratio (DA90?DA10)/DA50 ranges from 1.855 to 2.375, wherein DA90, DA50, and DA10 respectively denote the particle sizes corresponding to 90%, 50%, and 10% of the area cumulative distribution.

Abstract: A positive electrode active material, a positive electrode plate, a secondary battery, and a power consuming apparatus are provided. The positive electrode active material includes (i) secondary particles and (ii) single-crystal or quasi-single-crystal particles. The secondary particles are mainly formed by aggregating primary particles and the secondary particles further include an M1 element. The M1 element includes a transition metal element other than iron. A mass content of the M1 element is X1 based on a total mass of the secondary particles, where 500 ppm?X1?5000 ppm, and optionally, 800 ppm?X1?2000 ppm. The single-crystal or quasi-single-crystal particles include an Ma element. The Ma element includes a transition metal element other than iron. A mass content of the Ma element is X2 based on a total mass of the single-crystal or quasi-single-crystal particles, where X2 is less than X1.

Abstract: A friction-reducing and wear-resistant polyamide-imide composite material, a preparation method thereof and an application method therefor are provided, which relate to the technical field of polymer materials. The composite material includes the following raw materials in part by weight: 100 parts of basic slurry, 0.1-20 parts of functional filler, 0-50 parts of diluent, 0.1-1 part of defoamer, and 0.1-1 part of dispersant. The basic slurry is aqueous polyamide-imide emulsion. The functional filler is a biomass carbon composite molybdenum disulfide material treated with a siloxane coupling agent, and a source of biomass carbon is cattail-derived carbon fibers. The composite material has advantages of low friction coefficient and wear rate, wide raw material sources, environmental friendliness, and high dispersion stability. The preparation method has a simple and convenient process and can meet demands for planned production.

Abstract: A method and a device for data migration of a blockchain. The method includes generating a state tree based on state data of accounts in the blockchain, in which the state tree is a B+ tree based on a copy-on-write technology, and each leaf node of the state tree is configured to store the state data; determining a target state tree to be migrated from the generated state tree when data migration is triggered; sending state data of the target state tree to an extended node of a master node; if migration completion information is received from the extended node, updating a data mapping table stored in the master node, in which the data mapping table is configured to represent a mapping relationship between state data stored in the extended node and the extended node; and deleting the target state tree in the master node.

Abstract: A B+-tree-based data management method includes writing, when a first write operation on a node data of a B+ tree is detected, the node data to a base page of a disk, wherein the base page contains a pointer field configured to indicate an associated delta page; creating a first delta record in a delta page based on the base page, when a first write operation on a target entry in the base page is detected; creating a second delta record in the delta page when a second write operation on the target entry is detected, the second delta record is used to record second data corresponding to the second write operation. Accordingly, a waste of disk space may be reduced, and complexity of read-write operations may be lowered.

Abstract: A positive electrode active material, a positive electrode plate, a secondary battery, and a power consuming apparatus are provided. The positive electrode active material includes (i) secondary particles and (ii) single-crystal or quasi-single-crystal particles. The secondary particles are mainly formed by aggregating primary particles and the secondary particles further include an M1 element. The M1 element includes a transition metal element other than iron. A mass content of the M1 element is X1 based on a total mass of the secondary particles, where 500 ppm?X1?5000 ppm, and optionally, 800 ppm?X1?2000 ppm. The single-crystal or quasi-single-crystal particles include an Ma element. The Ma element includes a transition metal element other than iron. A mass content of the Ma element is X2 based on a total mass of the single-crystal or quasi-single-crystal particles, where X2 is less than X1.

Abstract: A method for privacy protection of smart contract includes: obtaining a variable identifier, a privacy-trigger sub-script, and ciphertexts of a plurality of privacy-trigger sub-scripts of other participating users input by the user intending to perform a transaction in response to a transaction instruction; determining a target state variable corresponding to the variable identifier from the smart contract, and obtaining a precomputed ciphertext corresponding to the target state variable; computing, using the preset digest algorithm, based on the plurality of privacy-trigger sub-scripts and the ciphertexts of the plurality of privacy-trigger sub-scripts to obtain the target ciphertext; executing a decision-making script bytecode in the privacy-trigger sub-script to obtain an execution result if the target ciphertext is identical to the precomputed ciphertext; and performing a predetermined operation on the target state variable when the execution result indicates execution success.

Abstract: The present disclosure provides a consensus method and a consensus apparatus for a blockchain system. The consensus method includes: generating a subsequent proposal block by referencing a plurality of proposal blocks and combining current transactions from clients in an (n+x2)-th consensus round; and achieving consensus on the preceding proposal block by using the subsequent proposal block as a certificate for the preceding proposal block. The plurality of proposal blocks are correspondingly generated by the plurality of validation nodes referencing a preceding proposal block in an n-th consensus round, and the preceding proposal block is generated in an (n?x1)-th consensus round. In the consensus method of the present disclosure, there is no need to transmit a large amount of signature messages in the consensus process, and consensus on a specific block is achieved by establishing reference relationships between blocks generated in different consensus rounds.

Abstract: The invention provides a non-contact indoor thermal environment control system and a method based on reinforcement learning, which adopts a non-contact measurement mode to collect the video information of indoor personnel and judge the hot/cold state of the personnel through the processing of the video information. It can reduce the intrusiveness caused by the use of measuring equipment. At the same time, the invention adopts the reinforcement learning method to train and obtain the optimal thermal environment control strategy according to the environmental information, the hot and cold state of the personnel and the previous regulation strategy, which not only considers the difference of individual thermal comfort, but also satisfies the dynamic thermal comfort of personnel, improves the regulation efficiency of indoor thermal environment. At the same time, it can reduce the energy consumption of HVAC, achieve a sustainable state of energy saving and environmental protection.

Abstract: The invention discloses a spray cooling fan control system and method based on computer vision technology. The data acquisition system monitors person thermal comfort through various non-contact measurement methods, which improves the accuracy and instantaneity and achieves human thermal comfort and energy saving. The information processing system adjusts the air and spray volume based on human skin temperature and thermal sensation and plans the mobile path. The mobile control system moves the spray cooling fan to the optimal location so that the mobility and flexibility are enhanced. The intelligent voice interaction system and the end control system control the opening of the fan intelligently and humanely so that people become the main subject which controls the environmental temperature optimization equipment. Consequently, the invention cools person precisely and meets the thermal environment control and personnel thermal needs quickly.

Abstract: A positive electrode active material, a positive electrode plate, a secondary battery, and a power consuming apparatus are provided. The positive electrode active material includes (i) secondary particles and (ii) single-crystal or quasi-single-crystal particles. The secondary particles are mainly formed by aggregating primary particles and the secondary particles further include an M1 element. The M1 element includes a transition metal element other than iron. A mass content of the M1 element is X1 based on a total mass of the secondary particles, where 500 ppm?X1?5000 ppm, and optionally, 800 ppm?X1?2000 ppm. The single-crystal or quasi-single-crystal particles include an Ma element. The Ma element includes a transition metal element other than iron. A mass content of the Ma element is X2 based on a total mass of the single-crystal or quasi-single-crystal particles, where X2 is less than X1.

Abstract: The positive electrode sheet comprises a positive electrode film layer located on at least one side of a current collector The particle size distribution index of an active material in the first area of the positive electrode film layer is smaller than the particle size distribution index of an active material in the second area of the positive electrode film layer The particle size distribution index is the ratio of the standard deviation of the particle size of an active material to the average particle size thereof, the first area is an area where the positive electrode film layer extends vertically from the surface on the side close to the current collector to the positive electrode film layer within a distance h1, the second area is an area where the positive electrode film layer extends vertically from the surface on the side close to the current collector.

Abstract: This application provides a composite positive electrode material and preparation method thereof, a positive electrode plate, a secondary battery, and an electric apparatus. The preparation method includes: mixing a lithium source, a phosphorus source, an iron source, a carbon source, and a carbon graphitization catalyst in a predetermined ratio with a solvent to form a mixed slurry; grinding and drying the mixed slurry to obtain a mixed dry substance; and sintering the mixed dry substance to obtain the composite positive electrode material, a sintering temperature being 750° C.-840° C.

Abstract: A positive electrode plate includes a positive current collector and a positive electrode film layer. The positive electrode film layer is disposed on at least one surface of the positive current collector. The positive electrode film layer includes a first positive electrode film layer and a second positive electrode film layer. The first positive electrode film layer is located between the positive current collector and the second positive electrode film layer. The first positive electrode film layer includes a first positive active material. A specific surface area of the first positive active material is 12 m2/g to 16 m2/g. The second positive electrode film layer includes a second positive active material. A specific surface area of the second positive active material is 6 m2/g to 19 m2/g.

Abstract: A composite positive electrode material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The composite positive electrode material includes a composite formed by a positive active material and carbon. In a particle structure of the composite, a mass ratio of a carbon content inside to a carbon content on a surface is (0.8 to 2):1.

Abstract: A control system and a control method of refrigeration in a closed space based on computer vision are provided. An image of a food, temperature and humidity information in the closed space are collected, and a type of the food is identified according to the image. The image is processed through Euler video amplification when food is not packaged to obtain surface color distribution information of the food, a state of the food is determined according to the surface color distribution information and a historical learning result, and a state prompt corresponding to the state of the food is provided to a user. Temperature and humidity in the closed space are regulated according to the state of the food. The state of the food is determined according to storage time and a known quality guarantee period when the food is packaged, and another state prompt is provided to the user.

Abstract: Implementations of the present specification provide methods and apparatuses for training a behavior prediction model. In the implementations of the present specification, a sequence (a behavior sequence of a user) that includes multiple behavior types is split according to behavior types to obtain multiple single-behavior sequences. Time coding is performed on all time points of each of the multiple single-behavior sequences, to obtain multiple single-behavior time sequences corresponding to the multiple single-behavior sequences. Each single-behavior time sequence in the multiple single-behavior time sequences is modeled by using a behavior prediction model, and attention is paid to all time points of each single-behavior time sequence in the multiple single-behavior time sequences, so as to obtain a distribution situation of behaviors corresponding to the multiple single-behavior time sequences in terms of time as predicted by the behavior prediction model.