Abstract: A converter system includes a plurality of converters, a sampling circuit, and a control circuit. The plurality of converters are connected in parallel. Each converter includes a detection circuit which includes a first switch and at least two resistors. The first switch is connected in parallel with one of the at least two resistors. The control circuit control the sampling circuit to collect a first voltage and a second voltage, where the first voltage is a voltage that is between a second bus and a ground cable and that is collected by the sampling circuit when first switches in detection circuits of a first quantity are in a turn-on state, the second voltage is a voltage that is between the second bus and the ground cable and that is collected by the sampling circuit when first switches in detection circuits of a second quantity are in a turn-on state.

Abstract: Provided is a medical device implantation apparatus, comprising: an outer sheath, connected to a first portion of a handle and extending from a proximal end to a distal end; a middle sheath, the middle sheath being arranged in the outer sheath, and the middle sheath being connected to a second portion of the handle; an inner sheath, the inner sheath being allowed to pass through the middle sheath, the inner sheath being connected to a third portion of the handle, and the inner sheath being movable relative to the outer sheath; outer casings, with at least two outer casings being provided, and a distal end of the inner sheath being respectively fixedly connected to the outer casings; and a medical device, arranged around the inner sheath and partially accommodated in the outer casings.

Abstract: A terminal is disclosed including a selection unit that selects first resource candidates for sidelink transmission based on monitoring in a sensing window, and specifies second resource candidates by excluding specific periodic resources that are reserved by another terminal from the first resource candidates; and a transmission unit that performs sidelink transmission using a resource selected from the second resource candidates. In another aspect, a transmission method executed by a terminal is also disclosed.

Abstract: A key-value store and a file system are integrated together to provide improved operations. The key-value store can include a log engine, a hash engine, a sorting engine, and a garbage collection manager. The features of the key-value store can be configured to reduce the number of I/O operations involving the file system, thereby improving read efficiency, reducing write latency, and reducing write amplification issues inherent in the combined key-value store and file system.

Abstract: The present disclosure provides an immobilized crude enzyme for degrading complex polycyclic aromatic hydrocarbons (PAHs) in soil and a preparation method thereof, and relates to the field of remediation of complex organics-polluted soil. The present disclosure particularly relates to an immobilized crude enzyme and a preparation method thereof. In the present disclosure, the immobilized crude enzyme for degrading complex PAHs in soil is prepared from an acid-modified chestnut inner shell and a crude enzyme solution of white rot fungi; and there are copper ions in the crude enzyme solution of the white rot fungi. The preparation method includes: 1, preparing a chestnut inner shell into a powdered material; 2, preparing modified biochar; 3, conducting immobilization.

Abstract: An automatic concrete dam defect image description generation method based on graph attention network, including: 1) extract the local grid features and whole image features of the defect image and conduct image coding by using multi-layer convolutional neural network; 2) construct the grid feature interaction graph, and fuse and encode the grid visual features and global image features of the defect image; 3) update and optimize the global and local features through the graph attention network, and fully utilize the improved visual features for defect description. The invention constructs the grid feature interaction graph, updates the node information by using the graph attention network, and realizes the feature extraction task as the graph node classification task. The invention can capture the global image information of the defect image and the potential interaction of local grid features, and the generated description text can accurately and coherently describe the defect information.

Abstract: This application provides a photovoltaic system and a power supply current control method thereof. The photovoltaic system includes a direct current bus and at least two power supply units connected in parallel to the direct current bus. The power supply current control method of a photovoltaic system includes: obtaining a current power supply state parameter of each of the at least two power supply units, determining a reference power supply current value of each power supply unit based on the current power supply state parameter of each power supply unit, and adjusting a current supply power of each power supply unit based on the reference power supply current value of each power supply unit. According to this application, appropriate load distribution between power supply units can be ensured, and applicability is high.

Abstract: A control system and method for a power supply system. The control system includes a front controller and a front voltage conversion circuit and a post controller and a post voltage conversion circuit. The front voltage conversion apparatus is configured to supply power to the post voltage conversion apparatus through a direct current bus. The post voltage conversion apparatus is configured to: receive electric energy transmitted by the front voltage conversion apparatus through the direct current bus, and supply power to a power grid. The post controller is further configured to transmit, to the front controller through the direct current bus, information indicating that high voltage ride-through occurs on the power grid. Voltage control on the direct current bus does not need to depend on the high-speed communication cable, thereby improving control efficiency of a power supply system.

Abstract: A time-series image description method for dam defects based on local self-attention mechanism is provided, including: performing frame sampling on an input time-series image of dam defect, extracting a feature sequence using a convolutional neural network and using the sequence as an input to a self-attention encoder, where the encoder includes a Transformer network based on a variable self-attention mechanism that dynamically establishes contextual feature relations for each frame; generating description text using a long short term memory (LSTM) network based on a local attention mechanism to enable each word predicted to be feature related to an image frame, improving text generation accuracy by establishing a contextual dependency between image and text. A dynamic mechanism is added to the present application for calculating the global self-attention of image frames, and LSTM networks with added local attention directly establish the correspondence between image and text modal data.

Abstract: A photovoltaic power generation system and a method and a device for detecting an earth fault of a photovoltaic string. The controller obtains a terminal voltage of each photovoltaic string before voltage disturbance, where the terminal voltage is a voltage to earth of a positive electrode or negative electrode of the photovoltaic string; performs voltage disturbance on each photovoltaic string and obtains a terminal voltage of each photovoltaic string after the voltage disturbance; determines a photovoltaic string with an earth fault based on the terminal voltage of each photovoltaic string before and after the voltage disturbance; obtains a photovoltaic panel with an earth fault by using the terminal voltage and an output voltage of the photovoltaic string before the voltage disturbance, or obtains a photovoltaic panel with an earth fault by using the terminal voltage and an output voltage of the photovoltaic string after the voltage disturbance.

Abstract: The invention discloses a strontium ferrite-based sacrificial mortar and its preparation method, the strontium ferrite-based sacrificial mortar mainly comprises 720-1000 parts of sulphoaluminate cement, 100-300 parts of strontium ferrite, 600-650 parts of quartz sand, 400-450 parts of water and 0.01-35 parts of superplasticizer. The preparation process is simple, and the strontium ferrite-based sacrificial mortar can be prepared by using a conventional forced single horizontal shaft concrete mixer. The obtained mortar has excellent working performance, compressive strength and corrosion resistance. It can be used in the current third and future fourth generation nuclear power plant core catchers, and has obvious engineering application value.

Abstract: The invention relates to a composite shock absorber for a polycrystalline diamond compact bit, comprising a drilling tool body having a water inlet, an impact body having a water outlet and forming a shock absorption cavity, a disc spring group having an annular pressing sleeve, a cylindrical torsion bar spring which has an external thread and a spline, is connected to the drilling tool body through threads and extended into an impactor and connected thereto through the spline, and the annular pressing sleeve, wherein bit vibration impact force is transmitted therebetween through a torsion transmission joint, and a bearing group is arranged between the lower end surface of the annular pressing sleeve and an annular step of the impact body. The composite shock absorber can weaken damage of the slippage effect to polycrystalline diamond compact cutting teeth, absorb axial vibration from a drill stem and prolong the service life of the bit.

Abstract: The present disclosure provides a method, apparatus, medium and device for extracting a river drying-up region and frequency, and belongs to the technical field of remote sensing. The method for extracting a river drying-up region and frequency can be applied to efficiently acquiring river drying-up information for a long time within the large spatial region. With the inverse normalized difference water index (iNDWI) and the maximum value composite (MVC) method for the remote sensing images, the present disclosure omits the troublesome step of separately extracting a river range for each image in the conventional method. In addition, the present disclosure quickly obtains the drying-up frequency by counting the total number of available images and the number of non-water images at the same pixel position, and yields a greater efficiency for extracting the river drying-up region and frequency.

Abstract: A converter system includes a plurality of converters, a sampling circuit, and a control circuit. The plurality of converters are connected in parallel. Each converter includes a detection circuit which includes a first switch and at least two resistors. The first switch is connected in parallel with one of the at least two resistors. The control circuit control the sampling circuit to collect a first voltage and a second voltage, where the first voltage is a voltage that is between a second bus and a ground cable and that is collected by the sampling circuit when first switches in detection circuits of a first quantity are in a turn-on state, the second voltage is a voltage that is between the second bus and the ground cable and that is collected by the sampling circuit when first switches in detection circuits of a second quantity are in a turn-on state.

Abstract: Provided is a heat transfer composition, which is characterized in that the heat transfer composition comprises the following three components: 1,1,1,2-tetrafluoroethane (R134a) with a mass ratio of 28%-46%, 2,3,3,3-tetrafluoropropene (R1234yf) with a mass ratio of 33%-71%, and trans 1,3,3,3-tetrafluoropropene (R1234ze(E)) with a mass ratio of I %-23%. The described heat transfer composition which replaces R134a not only has the environmentally friendly features of having low GWP and zero ODP, but also has excellent thermal performance. When applied in a centrifugal chiller, the volumetric refrigeration capacity and energy efficiency are equivalent to those of a centrifugal unit using an R134a refrigerant, and the slip in temperature is small; thus, the present application may become a heat transfer composition to replace R134a.

Abstract: A complex surface three-coordinate measuring device includes a three-degree-of-freedom motion platform and a force control probe, the force control probe is fixedly mounted on the Z-axis sliding block, which is in the same direction as the X-axis direction and used to contact with the workpiece surface with constant force. A six-axis force sensor is used to collect the contact force between the stylus and the workpiece surface. In this method, the force control is realized in the measurement to make the stylus in constant force contact with the workpiece surface. The error compensation direction is determined according to the direction of the contact force, and then the effective radius of the stylus spherical head is compensated in this direction, thus the actual contact point of stylus and workpiece can be obtained.

Abstract: The invention relates to a composite shock absorber for a polycrystalline diamond compact bit, comprising a drilling tool body having a water inlet, an impact body having a water outlet and forming a shock absorption cavity, a disc spring group having an annular pressing sleeve, a cylindrical torsion bar spring which has an external thread and a spline, is connected to the drilling tool body through threads and extended into an impactor and connected thereto through the spline, and the annular pressing sleeve, wherein bit vibration impact force is transmitted therebetween through a torsion transmission joint, and a bearing group is arranged between the lower end surface of the annular pressing sleeve and an annular step of the impact body. The composite shock absorber can weaken damage of the slippage effect to polycrystalline diamond compact cutting teeth, absorb axial vibration from a drill stem and prolong the service life of the bit.

Abstract: The present application provides a control method for a vehicle air conditioner, including: performing remote control in advance, wherein performing remote control in advance includes performing remote timing control in advance. Performing remote timing control in advance includes starting the air conditioner t0 minutes before the vehicle is started, so as to perform pre-cooling or pre-heating, wherein t0 is a constant. Compared with a vehicle air conditioner in the prior art, the vehicle air conditioner in the present application performs, by a configured step of performing remote control in advance, pre-cooling or pre-heating before the vehicle is started, so as to control an interior temperature of the vehicle in advance, such that when a user enters the vehicle, a comfortable ambient temperature is provided, thereby providing a comfortable ambient for a vehicle owner and a passenger.