Abstract: The disclosure provides a power tool and power tool system, including: a first slot and a second slot; when the power tool is in a double-pack working state, battery packs are respectively arranged in the first slot and the second lot; when the power tool is in a single-pack working state, the battery pack is arranged in the first slot or the second slot, and both the double-pack working state and the single-pack working state provides a same rated voltage to the power tool

Abstract: A cache validation system receives Content Delivery Network (CDN) caching rules and a request log, such as a log of HTTP requests received by a CDN. The cache validation system generates test requests from the CDN caching rules and the request log. In a testing environment, the cache validation system determines one or more cache validation indicators, such as, but not limited to, a hit-to-miss value, from the test requests and the CDN caching rules before application of a proposed change to a CDN caching rule. The cache validation system applies the proposed change to the CDN caching rules in the testing environment. The cache validation system determines one or more updated cache validation indicators from the test requests for the CDN caching rules after application of the proposed change. If the initial and updated cache validation indicator(s) satisfy a threshold, then the cache validation system can provide a notification.

Abstract: Disclosed are a screen projection method and device of a projector, an electronic device, and a storage medium. When a projector receives a projection instruction to project a target screen through the projector, projection scenario information of the projector in a current projection scenario and a preset historical projection record may be acquired. Then, target projection information matching the current projection scenario may be determined based on the acquired projection scenario information and historical projection record. The target screen may be corrected based on the target projection information. The corrected target screen may be projected via the projector. This process may correct the projection screen of the projector efficiently and simply after the projection scenario of the projector is changed, thereby efficiently and accurately.

Abstract: The disclosure provides a power tool and power tool system, including: a first slot and a second slot; when the power tool is in a double-pack working state, battery packs are respectively arranged in the first slot and the second lot; when the power tool is in a single-pack working state, the battery pack is arranged in the first slot or the second slot, and both the double-pack working state and the single-pack working state provides a same rated voltage to the power tool.

Abstract: The battery pack includes a housing, and a battery module, a plurality of busbars, and an insulated first isolation tape that are accommodated in the housing. The battery module includes a plurality of cells arranged in a length direction of the battery pack, the plurality of busbars are disposed on a surface on which poles of the plurality of cells are located, two adjacent cells in the plurality of cells are electrically connected via one of the plurality of busbars, and the first isolation tape extends in the length direction of the battery pack and covers a surface that is of the plurality of busbars and that is away from the plurality of cells. There is a gap between the first isolation tape and pressure relief valves of the plurality of cells in a direction in which the poles and the pressure relief valves are spaced from each other.

Abstract: A circuit board structure includes a flexible core board, a first circuit layer, a first solder mask layer, a first protective layer, a rigid plate and a plurality of electrically-conductive members. The flexible core board includes a first surface and a second surface. The first circuit layer is formed on the first surface, and has a plurality of electrical connection portions. The first solder mask layer is coated on the first circuit layer and the first surface. The first solder mask layer has a plurality of opening portions aligned with the electrical connection portions. The first protective layer is disposed on the first solder resist layer and has a flat surface. The rigid plate is disposed on the second surface and corresponds to the opening portions. The electrically-conductive members are respectively formed on the electrical connection portion and exposed from the opening portion.

Abstract: A display method and an electronic device are provided. The method is applied to a folding-screen electronic device including a first display portion and a second display portion. The method includes: displaying, based on an observation point of a user and a three-dimensional model of a preset object at a first moment, a first projected image of the preset object through the first display portion, and displaying a second projected image of the preset object through the second display portion when it is determined that a folding-screen electronic device is in a half-folded state; and displaying, based on a second position, a third projected image of the preset object through the first display portion, and displaying a fourth projected image of the preset object through the second display portion when it is detected that the observation point of the user is moved from a first position to the second position.

Abstract: A composite mounting type electrical connector includes an insulating shell, a plurality of terminals and a plurality of shielding members. The terminals are arranged in two rows parallel to each other, and the shielding members are arranged between the two rows of terminals and separated from each other by a predetermined distance to form insulation. The two rows of terminals are soldered to a circuit board by surface mounting technology and dual in line package process respectively. The ground terminals in the two columns of terminals are commonly connected to a shield member to form a common ground structure. The power terminals in the two columns of terminals are commonly connected to another shielding member to form a parallel connecting structure.

Abstract: The disclosure provides a battery charging circuit, a battery pack and a battery pack charging system. The battery charging circuit includes a first control switch, a switch control unit and a power supply unit. The first control switch is arranged between the charging positive terminal and the positive electrode of the battery pack, or between the charging negative terminal and the negative electrode of the battery pack, and it is an NMOS transistor with a body diode. The switch control unit is connected to the gate, source, and drain of the first control switch and controls the on-off of the first control switch by sampling a voltage between the source and the drain of the first control switch. The output end of the power supply unit is connected to the power source end of the switch control unit to supply power to the switch control unit.

Abstract: The invention provides a voltage balancing system for balancing controlling of voltage of battery cells including a first set of battery cells and a second set of battery cells connected in series. The system includes a high-side analog front end (AFE) connected to the first set of battery cells, a low-side analog front end (AFE) connected to the second set of battery cells, a microcontroller communicating with the high-side AFE and the low-side AFE, and a communication isolating module interconnecting between the high-side AFE and the microcontroller. The system further includes a balancing module arranged at a back end of the low-side AFE or the high-side AFE to equalize voltages output by the low-side AFE and the high-side AFE. Compared with the prior arts, the system employs a balancing module to balance the voltages of the two sets of battery cells, which can shorten the voltage difference therebetween.

Abstract: Disclosed in the present disclosure are a liquid level measurement device, method and apparatus, a storage medium, and a 3D printer, relating to the technical field of liquid level measurement. The liquid level measurement device comprises: a first excitation circuit, configured to output a first voltage signal according to a first excitation signal and a current liquid level; a first detection circuit, configured to extract a peak voltage of the first voltage signal; and a comparison and amplification circuit, configured to output a second voltage signal according to the peak voltage and a first preset reference voltage, wherein the second voltage signal is configured to represent a height corresponding to the current liquid level. Small space is occupied, and the detection accuracy is high.

Abstract: An electrically conducting structure for a flexible circuit board, comprising a flexible substrate, a circuit layer, a soldering structure and an electrically connecting structure. The flexible substrate includes a first surface, a second surface, a lateral surface and a plurality of grooves. The first surface is opposite to the second surface, and the lateral surface connects the first surface and the second surface. The grooves are formed on the lateral surface and connect the first surface and the second surface. The circuit layer is formed on the first surface and includes an electrically conducting structure located near the lateral surface. The soldering structure is formed on the second surface. The electrically connecting structure extending form the first surface to the second surface connects the electrically conducting structure and the soldering structure.

Abstract: A forward and reverse bidirectional flow rate measurement method for a subsea chemical agent injection device is provided. The device includes a device body, a flow channel is formed inside the device body, the device body includes an agent input connector, a pressure reduction member, a needle valve assembly, and an agent output connector that are sequentially communicated through the flow channel; and the method is implemented by: calibrating forward and reverse flow of agents at different openings and flow rates, then obtaining differential pressures before and after the agents flow through the needle value assembly; fitting relationships between the flow rates and the differential pressures at different openings to obtain a plurality of arrays of opening-flow coefficients; then fitting relationships between the flow coefficients and the needle valve openings to establish a formula for the flow rate and the opening-differential pressure, and finally performing the measurement in real time.

Abstract: An electrically conducting structure for a flexible circuit board, comprising a flexible substrate, a circuit layer, a soldering structure and an electrically connecting structure. The flexible substrate includes a first surface, a second surface, a lateral surface and a plurality of grooves. The first surface is opposite to the second surface, and the lateral surface connects the first surface and the second surface. The grooves are formed on the lateral surface and connect the first surface and the second surface. The circuit layer is formed on the first surface and includes an electrically conducting structure located near the lateral surface. The soldering structure is formed on the second surface. The electrically connecting structure extending form the first surface to the second surface connects the electrically conducting structure and the soldering structure.

Abstract: The disclosure provides a battery charging circuit, a battery pack and a battery pack charging system. The battery charging circuit includes a first control switch, a switch control unit and a power supply unit. The first control switch is arranged between the charging positive terminal and the positive electrode of the battery pack, or between the charging negative terminal and the negative electrode of the battery pack, and it is an NMOS transistor with a body diode. The switch control unit is connected to the gate, source, and drain of the first control switch and controls the on-off of the first control switch by sampling a voltage between the source and the drain of the first control switch. The output end of the power supply unit is connected to the power source end of the switch control unit to supply power to the switch control unit.

Abstract: A forward and reverse bidirectional flow rate measurement method for a subsea chemical agent injection device is provided. The device includes a device body, a flow channel is formed inside the device body, the device body includes an agent input connector, a pressure reduction member, a needle valve assembly, and an agent output connector that are sequentially communicated through the flow channel; and the method is implemented by: calibrating forward and reverse flow of agents at different openings and flow rates, then obtaining differential pressures before and after the agents flow through the needle value assembly; fitting relationships between the flow rates and the differential pressures at different openings to obtain a plurality of arrays of opening-flow coefficients; then fitting relationships between the flow coefficients and the needle valve openings to establish a formula for the flow rate and the opening-differential pressure, and finally performing the measurement in real time.

Abstract: A plug electrical connector and an electrical connector combination having the same are disclosed. The plug electrical connector includes a plug insulation structure; a plurality of plug terminals joined to the plug insulation structure; a movable member movably disposed on the plug insulation structure; at least one contact terminal joined to the movable member; wherein the at least one contact terminal and the movable member move simultaneously between a contact position and a retreat position. The electrical connector combination includes the aforementioned plug electrical connector and a receptacle electrical connector. The receptacle electrical connector includes a receptacle insulation structure; a plurality of receptacle terminals joined to the receptacle insulation structure; at least one detecting terminal joined to the receptacle insulation structure. The contact terminal is selectively to contact the detecting terminal, whereby certain specific functions of an electronic device are activated.

Abstract: Recombinant viral vectors are disclosed that contain a nucleic acid encoding a Second Mitochondria-derived Activator of Caspases (Smac) protein inserted within an RNA virus genome, wherein the Smac protein specifically binds to at least a portion of an Inhibitor of Apoptosis Protein (IAP). Also disclosed are methods of treating cancer using the disclosed vectors.

Abstract: A battery pack apparatus includes a housing, a support frame, at least one battery cell module, a heat dissipation air duct, at least one first fan and a controller. The support frame is disposed within a accommodating space of the housing. The at least one battery cell module is mounted in the accommodating space via the support frame. The heat dissipation air duct is formed within the accommodating space. Two ends of the heat dissipation air duct are respectively in communication with air vents on the opposite sides of the housing. The at least one first fan is capable of bidirectional rotation, is disposed within the accommodating space, and is positioned adjacent to one of the air vents.

Abstract: The present disclosure provides methods for reducing methane emissions from a ruminant comprising administering to the ruminant bromoform produced by a composition comprising: bromide, and a vanadium-dependent haloperoxidase (VHPO) comprising SEQ ID NO: 2 or a variant protein thereof.