Abstract: An autonomous ship bottom inspection method by a ROV(s) based on a ship 3D model in STL format is provided. The ship 3D model is obtained and a surface thereof is spliced by triangular facets. Body 3D coordinate points of the ship 3D model are obtained and then expanded according to a safety distance of ROV and ship to obtain inspection track points of the ROV. The ship 3D model is divided into regions, and the inspection track points in each region are performed with interpolation and smoothing. Smoothed inspection track points of the regions are connected as per a result of the dividing to obtain a ship bottom inspection track, a real-time position of the ROV is obtained, a ship bottom inspection path is generated based on the ship bottom inspection track and the real-time position. The ROV is controlled to move as per the ship bottom inspection path.

Abstract: An optical fiber sensing system for temperature and salinity synchronous measurement is provided, which includes a broad-spectrum light source, an optical fiber circulator, a coupler, a first interferometer, a second interferometer, a third interferometer and a spectrometer; the first interferometer is insensitive to temperature and salinity; the second interferometer is sensitive to both temperature and salinity, and the third interferometer is only sensitive to temperature; light emitted by the broad-spectrum light source passes through the optical fiber circulator and enters the first interferometer; reflected light of the first interferometer passes through the optical fiber circulator and the coupler sequentially, and then enters the second and the third interferometers respectively; the reflected light of the second and the third interferometers enters the spectrometer after passing through the coupler; the temperature and the salinity to be measured are simultaneously obtained by performing spectral an

Abstract: A method for preparing a carbon nano tube/polyacrylic acid hydrogel, a product and an application thereof are provided. The method includes: oxidizing a carbon nanotube into a carboxylated carbon nanotube, thereafter performing in-situ polymerization with acrylic acid, sodium hydroxide, ammonium persulfate, triethanolamine and N, N-methylenebisacrylamide to obtain a carbon nanotube/polyacrylic acid hydrogel. The hydrogel has a uniform porous structure, facilitating a rapid transmission and supply of water. The carbon nanotubes in the hydrogel are of an array structure, achieving a full absorption of solar energy to realize a high-efficiency photothermal conversion. The gel is attached to a sponge base to obtain a solar-powered carbon nano tube/polyacrylic acid hydrogel steam generator for the photothermal conversion. The steam generator is used for solar seawater desalination, but can improve evaporation rate and evaporation efficiency.

Abstract: The invention discloses a method for preparing an anticorrosive surface layer of a metal material in a marine environment by laser, which belongs to the technical field of laser processing. First, the laser cladding method is used to prepare a cladding surface layer on the surface of the metal material that is not easy to undergo chemical substitution reaction with the chlorides (NaCl, MgCl2 , CaCl2 etc.) in the seawater. Then, on the surface of the cladding surface layer, ultrafast laser processing is used to form a surface layer with a wetting angle (and water) greater than 90 degrees and with hydrophobic characteristics.

Abstract: A method for identifying pitch error and yaw error of a numerically-controlled (NC) machine tool, including: acquiring a Cartesian coordinate system of a target machine tool; setting each axis of the Cartesian coordinate system as movement axis, where each movement axis has three measurement trajectories, and the three measurement trajectories are mutually parallel to the corresponding axis, and not on the same plane; selecting an axis as the movement axis; and obtaining positioning error data between an actual operation measurement point and an ideal operation measurement point of the target machine tool when the target machine tool moves along the three measurement trajectories corresponding to the movement axis; and according to spatial angle geometric relationship and the positioning error data, obtaining a pitch error angle and a yaw error angle of the target machine tool.

Abstract: A composite hydrogel sponge and its preparation method and application, and a solar desalination device are provided. The composite hydrogel sponge includes a water supply layer and an evaporation layer disposed on the water supply layer. A material of the water supply layer is polyacrylamide hydrogel, and a material of the evaporation layer is polyacrylamide/graphene composite hydrogel. The polyacrylamide/graphene composite hydrogel includes the polyacrylamide hydrogel and the graphene dispersed in the polyacrylamide hydrogel. The composite hydrogel sponge has a special porous structure of the sponge, which is beneficial to the rapid transmission and supply of water; meanwhile, the graphene on the surface of the evaporation layer can fully receive solar energy to achieve higher photo-thermal conversion efficiency.

Abstract: An omnidirectional underwater vehicle includes an open-frame mechanism including a frame with top thrusters at four corners of a top end of the frame; mechanical arms disposed at a front end of the frame; and a rotary holder disposed in the frame and including a motor fixing plate, an upper bearing fixing plate and a lower bearing fixing plate. A cylindrical roller bearing is fixed between the upper bearing fixing plate and the lower bearing fixing plate, and an inner edge of the cylindrical roller bearing is provided with two bearing clip inner plates from top to bottom. A servo motor is fixed on the motor fixing plate, a bottom end of the bearing clip inner plate at the bottom is fixedly connected to a steering gear fixing plate, and a top end of the steering gear fixing plate is provided with fully waterproof steering gears installed with underwater thrusters.

Abstract: Disclosed are a method, a device, equipment and a medium for dynamic positioning of a semi-submersible offshore platform. The method includes: acquiring a real-time position of the platform; if the real-time position is different from a preset position, detecting an external force torque by a first torque detector; calculating a first target thrust produced by each of propellers, controlling the propellers to produce forces according to a first target thrust torque, and detecting an actual thrust torque; obtaining a fault condition of each of the propellers if the actual thrust torque is different from the first target thrust torque, indicating that the propellers have faults; recalculating a thrust of each of the propellers, a second target thrust torque, according to the fault condition, the external force torque and the preset formula set; and controlling each of the propellers to generate the thrust according to a corresponding second target thrust torque.

Abstract: A fiber optic temperature sensor, a sensing head structure, and a manufacturing method are provided. The fiber optic temperature sensor includes a broad spectrum light source, a first fiber optic coupler, a spectrometer, a first sensing interferometer, and a second sensing interferometer. The first sensing interferometer and the second sensing interferometer have opposite temperature responses. A first free spectral range corresponding to the first sensing interferometer is close to but not equal to a second free spectral range corresponding to the second sensing interferometer. In the fiber optic temperature sensor, two sensing interferometers both sensitive to temperature are used, and the two sensing interferometers have opposite temperature responses, thereby achieving an enhanced vernier effect, and improving the sensitivity of temperature measurement.

Abstract: The present invention provides an energy-saving quick-freezing method for golden pomfret. The method is putting golden pomfret into a liquid nitrogen quick-freezer with a cavity temperature of A, and when a core temperature of fish body reaches ?6 to ?4° C., turning off the liquid nitrogen quick-freezer; when the cavity temperature of the liquid nitrogen quick-freezer rises to B, starting the liquid nitrogen quick-freezer, and when the core temperature of the fish body reaches ?19 to ?17° C., turning off the liquid nitrogen quick-freezer; and taking out the golden pomfret and storing at ?19 to ?17° C.; wherein, the A is ?105 to ?85° C., the B is ?95 to ?65° C., and A<B.

Abstract: Disclosed is a device for repairing deep-water cage nets. The device includes an open-frame underwater robot and a repairing mechanism of deep-water cage nets, where the repairing mechanism of deep-water cage nets includes a hole penetrating mechanism, a wire feeding mechanism, a rotary knotting mechanism, a steel wire cutting mechanism and steel wire clamping mechanisms. The hole penetrating mechanism comprises mechanical claws and a control box for controlling the mechanical claws. The wire feeding mechanism and the steel wire cutting mechanism are both fixedly arranged in the control box, and the steel wire clamping mechanisms and the rotary knotting mechanism are both arranged between two mechanical claws. The open-frame underwater robot is detachably connected with the repairing mechanism of deep-water cage nets through a connecting shaft.

Abstract: A fiber optic temperature sensor, a sensing head structure, and a manufacturing method are provided. The fiber optic temperature sensor includes a broad spectrum light source, a first fiber optic coupler, a spectrometer, a first sensing interferometer, and a second sensing interferometer. The first sensing interferometer and the second sensing interferometer have opposite temperature responses. A first free spectral range corresponding to the first sensing interferometer is close to but not equal to a second free spectral range corresponding to the second sensing interferometer. In the fiber optic temperature sensor, two sensing interferometers both sensitive to temperature are used, and the two sensing interferometers have opposite temperature responses, thereby achieving an enhanced vernier effect, and improving the sensitivity of temperature measurement.

Abstract: A controllable semi-open mariculture cabin system is provided, including a mariculture cabin, a water inlet mechanism, a filtering mechanism, and a fish outlet pipe. The water inlet mechanism includes a water inlet pipe and a plurality of high-pressure water inlet pipes. The water inlet pipe is located on one side of an upper part of the mariculture cabin. The plurality of high-pressure water inlet pipes are distributed in a circumferential direction of a top of the mariculture cabin. Tail ends of the high-pressure water inlet pipes are connected to jet pipes extending into the mariculture cabin. The filtering mechanism is arranged at the bottom of the mariculture cabin. An outlet end of the filtering mechanism is located in sea water outside. The fish outlet pipe is provided on a cabin wall of the mariculture cabin. A gate valve capable of opening and closing is mounted on the fish outlet pipe.

Abstract: An air pressure sensor based on a suspended-core fiber and a side-hole fiber is provided and includes a broadband light source, an optical fiber circulator, a sensing head and a spectrometer; the optical fiber circulator is connected with the broadband light source, the sensing head and the spectrometer; the sensing head includes a single mode fiber, a multimode fiber, the suspended-core fiber and the side-hole fiber; the single mode fiber is connected with the suspended-core fiber through the multimode fiber; and the multimode fiber is connected with the side-hole fiber through the suspended-core fiber. The sensor uses a fabrication method of fiber fusion, and the operation is simple; the sensor has advantages of small volume, compact structure and convenient use; the sensor has good stability without adhesive; additionally, parallel connection of double cavities could produce vernier effects, so the sensor has good contrast of interference spectrum and high sensitivity.

Abstract: The present invention provides an energy-saving quick-freezing method for golden pomfret. The method is putting golden pomfret into a liquid nitrogen quick-freezer with a cavity temperature of A, and when a core temperature of fish body reaches ?6 to ?4° C., turning off the liquid nitrogen quick-freezer; when the cavity temperature of the liquid nitrogen quick-freezer rises to B, starting the liquid nitrogen quick-freezer, and when the core temperature of the fish body reaches ?19 to ?17° C., turning off the liquid nitrogen quick-freezer; and taking out the golden pomfret and storing at ?19 to ?17° C.; wherein, the A is ?105 to ?85° C., the B is ?95 to ?65° C., and A<B.

Abstract: Provided is a gene for trypsin-like serine protease, a protein encoded thereby and use thereof. The nucleotide sequence of the gene for trypsin-like serine protease is set forth in SEQ ID No. 1, the amino acid sequence of the protein encoded by the gene for trypsin-like serine protease is set forth in SEQ ID No. 2. The protein encoded by the gene provided by the present disclosure is capable of inhibiting P. aeruginosa, A. hydrophila, V. parahaemolyticus and V. harveyi.

Abstract: A Michelson interference optical fiber temperature sensor for detecting fringe contrast change is provided. It includes a light source, an optical fiber coupler connected to a first optical fiber and a second optical fiber, a coarse wavelength division multiplexer, a first photodetector, a second photodetector, a display device, and a processing circuit connected to the display device. The light source, optical fiber coupler and coarse wavelength division multiplexer are connected sequentially in that order. The coarse wavelength division multiplexer is connected to the first photodetector and the second photodetector individually. The first photodetector and the second photodetector are connected to the processing circuit. An end of the first optical fiber or the second optical fiber facing away from the optical fiber coupler is connected to a semiconductor. It has advantages of simple and fast manufacturing process, safe and reliable sensor, stable signal, low cost, high sensitivity and high precision.

Abstract: An error compensation system for a numerical control (NC) machine tool based on iterative learning control, including a trajectory generating module, a down-sampling module, a position controller, a first holder, a velocity-loop iterative learning controller, a velocity controller, a second holder and a control plant. The trajectory generating module is configured to generate a desired trajectory command including a first sampling command. The first sampling command is transmitted to the down-sampling module and the velocity-loop iterative learning controller. The first sampling command is down-sampled through the down-sampling module to obtain a second sampling command. The velocity-loop iterative learning controller is configured to receive the first sampling command, and obtain a first sampling error compensation sequence according to a first sampling error sequence and a first sampling error compensation sequence of a previous iteration machining process stored therein.

Abstract: A high-sensitivity high-temperature sensor based on dislocation welding of suspended optical fiber is provided and includes a broadband light source, an optical fiber circulator, a sensing head and a spectrometer. The optical fiber circulator is connected to the broadband light source, the sensing head and the spectrometer individually, the sensing head includes a first single-mode optical fiber, a multi-mode optical fiber, a suspended core optical fiber and a second single-mode optical fiber which are connected in sequence. The high-sensitivity high-temperature sensor has the following advantages: simple to manufacture, no need for expensive special equipment; small sizes, compact structure, easy to use; full optical fiber structure, which can measure high temperatures up to 1000 degrees; no need for adhesive, good sensor stability; double cavities in parallel can generate vernier effects with high sensitivity.

Abstract: A model inversion-based iterative learning control method for a printer and a printer system. An error of a desired trajectory and an actual displacement of a printing paper and an error of a reference input and an actual displacement of a motor are considered at the same time to construct an iterative learning control model for the printer based on an inversion model, so as to iteratively modify an error failing to meet requirements.