Abstract: The present disclosure provides an ecological governance method based on erosion prevention and control for a gentle slope farmland and relates to the technical field of ecological governance of farmlands. The ecological governance method based on erosion prevention and control for a gentle slope farmland includes the following steps: sampling a gentle slope farmland to investigate erosion thereof; and determining erosion of a gentle slope cultivated land and selecting a corresponding recovery strategy based on a detection result of a sample, a soil quality index (SQI), and a comprehensive vegetation quality index (VQI), where the recovery strategy includes a natural recovery method and a biological-farming comprehensive recovery method; enclosing the gentle slope cultivated land, fallowing the gentle slope cultivated land and reducing tillage; exterminating insect pests and poisonous weeds in the enclosed area; and turning over straws under soil by a cultivator. The growth of poisonous weeds is inhibited.

Abstract: The embodiment of the present disclosure provides an imaging method for a dispersion energy spectrum of surface waves, an electronic device, and a storage medium. The imaging method includes: obtaining first surface wave data, and the first surface wave data corresponding to a space-time domain representation; processing the first surface wave data to obtain the second surface wave data, and the second surface wave data corresponding to a space-frequency domain representation; and processing the second surface wave data based on a preset algorithm to obtain a first imaging result, the first imaging result corresponding to a slowness-frequency domain representation.

Abstract: A service chain fault detection method includes: determining, by a service forwarding entity (SFE), to communicate with a first service function (SF) node on a service chain after obtaining a first fault tracing detection request packet, wherein the first fault tracing detection request packet comprises a path identifier (ID), and the path ID is used to identify a path of the service chain; obtaining, by the SFE, an ID of the first SF node; and sending, by the SFE, a first fault tracing detection response packet to the device for initiating fault detection, wherein the first fault tracing detection response packet comprises the path ID and the ID of the first SF node.

Abstract: The disclosure provides a multi-type hydrate formation simulation system and a method thereof. The simulation system comprises a hydrate generator, a gas source device and a cryogenic cooler. The hydrate generator comprises a reactor, in which a formation simulation space is provided and can be selectively filled with a loose formation skeleton or a consolidated formation skeleton. The gas source device is configured to introduce natural gas at a preset pressure into the formation simulation space. The cryogenic cooler comprises a temperature-adjustable thermotank, in which the hydrate generator is arranged. The simulation system and method provided can be used to study the influence of consolidated hydrate formation structures and loose hydrate formation structures and particle contact modes on the physical properties of hydrate rock, and are of great significance to the interpretation of hydrate formation exploration data and the estimation of hydrate saturation.

Abstract: This application provides a method for obtaining a FIB of a device on a network. The network includes a verification system and a plurality of devices, and a first device is one of the plurality of devices. The first device receives a request message sent by the verification system, where the request message carries a command for obtaining a FIB of the first device that is generated at a specified time. The first device obtains the FIB or a FIB snapshot of the first device that is generated at the specified time. The first device adds the obtained FIB or FIB snapshot to a response message, and sends the response message to the verification system.

Abstract: The invention relates to intermediates useful in the preparation of halichondrin compounds, methods for preparing the same and use thereof, such as halichondrins, eribulin, or their analogs. The intermediates, the methods and use thereof are used for the synthesis of the C20-C26 fragment of halichondrin compounds. The raw materials in the synthetic route of the invention are cheap and easily obtained, the sources and the qualities of the raw materials are reliable. The choice of the methods useful in the synthesis of chiral central structures are based on the structural characteristics of the reactants, thus effectively improving the synthesis efficiency, reducing the difficulties and risks of product quality control, and avoiding the use of highly toxic and expensive organotin catalysts to significantly decrease costs and improve environmental friendliness.

Abstract: This application provides a method for obtaining a FIB of a device on a network. The network includes a verification system and a plurality of devices, and a first device is one of the plurality of devices. The first device receives a request message sent by the verification system, where the request message carries a command for obtaining a FIB of the first device that is generated at a specified time. The first device obtains the FIB or a FIB snapshot of the first device that is generated at the specified time. The first device adds the obtained FIB or FIB snapshot to a response message, and sends the response message to the verification system.

Abstract: The present invention relates to pyran-fused ring compounds, preparation methods thereof and use thereof, especially to pyran-fused ring compounds usable for preparing Halichondrin, Eribulin, or analogues thereof, preparation methods thereof and use thereof. Use of any of the compounds of formula (I) to (XIII) of the present invention in preparation of Halichondrin B, Eribulin, analogues thereof or C1-C13 moieties thereof. Provided in the present invention are intermediates usable for preparing Halichondrin B, Eribulin, or analogues thereof, especially the key product of C1-C13 moieties, preparation methods thereof and use thereof. The starting material for the synthesis pathway of the present invention is inexpensive and readily available with sustainable source and reliable quality.

Abstract: An intermediate compound is prepared and used for the synthesis of halichondrin B, eribulin or an analog thereof, particularly a structural fragment C27-C35 thereof. The starting materials of the synthetic route are readily available, and the optical purity of the starting materials can be ensured, so that the optical purity of the structural fragment C27-C35 in halichondrin B, eribulin or the analog thereof is ensured. Steps for constructing a chiral center of the structural fragment C27-C35 feature higher diastereoselectivity and yield, in particular preparation methods of compounds of formulae (X), (XI), (XVI) and (XV). By-products of partial reactions can be removed only by recrystallization, which results in easy purification and significant reduce in cost.

Abstract: This application provides a method for obtaining a FIB of a device on a network. The network includes a verification system and a plurality of devices, and a first device is one of the plurality of devices. The first device receives a request message sent by the verification system, where the request message carries a command for obtaining a FIB of the first device that is generated at a specified time. The first device obtains the FIB or a FIB snapshot of the first device that is generated at the specified time. The first device adds the obtained FIB or FIB snapshot to a response message, and sends the response message to the verification system.

Abstract: A multicast packet transmission method, apparatus, and system, where the method is applied to a multicast ring network and the method includes receiving, by a first network node in the multicast ring network through a first path in a clockwise direction of the multicast ring network, a first multicast packet from a second network node in the multicast ring network, receiving, by the first network node through a second path in an anticlockwise direction of the multicast ring network, a second multicast packet from the second network node, where a payload of the first multicast packet is the same as a payload of the second multicast packet, and forwarding, by the first network node, the first multicast packet or the second multicast packet to at least one multicast destination device connected to the first network node.

Abstract: A method is performed by a control device, and the method includes: obtaining a first request and a second request, where the first request includes a bandwidth required by a first service, the second request includes a bandwidth required by a second service; determining the bandwidth required by the first service, and the bandwidth required by the second service, that a bandwidth occupation conflict exists between the first request and the second request; obtaining a plurality of comprehensive allocation modes for the first service and the second service based on the bandwidth provided by the port, the bandwidth required by the first service, and the bandwidth required by the second service; and determining a preferred comprehensive allocation mode from the plurality of comprehensive allocation modes based on a bandwidth allocation policy group including a plurality of bandwidth allocation policies.

Abstract: The present invention relates to pyran-fused ring compounds, preparation methods thereof and use thereof, especially to pyran-fused ring compounds usable for preparing Halichondrin, Eribulin, or analogues thereof, preparation methods thereof and use thereof. Use of any of the compounds of formula (I) to (XIII) of the present invention in preparation of Halichondrin B, Eribulin, analogues thereof or C1-C13 moieties thereof. Provided in the present invention are intermediates usable for preparing Halichondrin B, Eribulin, or analogues thereof, especially the key product of C1-C13 moieties, preparation methods thereof and use thereof. The starting material for the synthesis pathway of the present invention is inexpensive and readily available with sustainable source and reliable quality.

Abstract: An embodiment provides a packet transmission method and apparatus, to resolve a problem that occurs when a packet cannot traverse a NAT device when VTEPs communicate with each other through the NAT device. The method is applied to a VXLAN including a first VTEP, a second VTEP, and a NAT device. The method includes: performing, by the first VTEP, VXLAN encapsulation on a first packet, obtaining a second packet; sending, by the first VTEP, the second packet to the second VTEP through the NAT device; and performing, by the second VTEP, VXLAN decapsulation on the received second packet, to obtain the first packet. The first packet is a packet to be sent by the first VTEP, a destination port number of the second packet is obtained based on a destination IP address of the second packet, and a source port number of the second packet is a preset port number.

Abstract: The frost-resistant assembled initial support structure of the tunnel for supporting a surrounding rock includes a bearing layer, an elastic compressible structure and an inflatable airbag. A gap space is formed between the bearing layer and the surrounding rock, and the inflatable airbag and the elastic compressible structure are provided in the gap space; and the inflatable airbag after being inflated and the elastic compressible structure jointly fill up the gap space. A construction method includes providing the bearing layer in the tunnel, and forming the gap space between the bearing layer and the surrounding rock; providing the inflatable airbag and the elastic compressible structure in the gap space; and inflating the inflatable airbag and filling up the gap space with the inflatable airbag and the elastic compressible structure.

Abstract: A controller receives an access request message of a to-be-served flow that is sent by a network device. The access request message includes an identifier of the to-be-served flow and an identifier of a terminal that sends the to-be-served flow. The controller determines service level information of the to-be-served flow based on the identifier of the terminal and the identifier of the to-be-served flow. The controller determines a transmission path of the to-be-served flow and a transmission path of a being-served flow based on the service level information of the to-be-served flow and service level information of the being-served flow. The controller publishes the transmission path of the to-be-served flow and the transmission path of the being-served flow to the network device.

Abstract: A service chain fault detection method includes: determining, by a service forwarding entity (SFE), to communicate with a first service function (SF) node on a service chain after obtaining a first fault tracing detection request packet, wherein the first fault tracing detection request packet comprises a path identifier (ID), and the path ID is used to identify a path of the service chain; obtaining, by the SFE, an ID of the first SF node; and sending, by the SFE, a first fault tracing detection response packet to the device for initiating fault detection, wherein the first fault tracing detection response packet comprises the path ID and the ID of the first SF node.

Abstract: This application discloses a service chain fault detection method and an apparatus. The method includes: determining, by a service forwarding entity (SFE), to communicate with a first service function (SF) node on a service chain after obtaining a first fault tracing detection request packet, wherein the first fault tracing detection request packet comprises a path identifier (ID), and the path ID is used to identify a path of the service chain; obtaining, by the SFE, an ID of the first SF node; and sending, by the SFE, a first fault tracing detection response packet to the device for initiating fault detection, wherein the first fault tracing detection response packet comprises the path ID and the ID of the first SF node.

Abstract: The invention relates to intermediates useful in the preparation of halichondrin compounds, methods for preparing the same and use thereof, such as halichondrins, eribulin, or their analogs. The intermediates, the methods and use thereof are used for the synthesis of the C20-C26 fragment of halichondrin compounds. The raw materials in the synthetic route of the invention are cheap and easily obtained, the sources and the qualities of the raw materials are reliable. The choice of the methods useful in the synthesis of chiral central structures are based on the structural characteristics of the reactants, thus effectively improving the synthesis efficiency, reducing the difficulties and risks of product quality control, and avoiding the use of highly toxic and expensive organotin catalysts to significantly decrease costs and improve environmental friendliness.

Abstract: This application provides a method for obtaining a FIB of a device on a network. The network includes a verification system and a plurality of devices, and a first device is one of the plurality of devices. The first device receives a request message sent by the verification system, where the request message carries a command for obtaining a FIB of the first device that is generated at a specified time. The first device obtains the FIB or a FIB snapshot of the first device that is generated at the specified time. The first device adds the obtained FIB or FIB snapshot to a response message, and sends the response message to the verification system.