Abstract: A helical antenna, including a printed circuit board and a radiating body provided above the printed circuit board. The radiating body includes at least one main helical arm and at least one parasitic helical arm. Each main helical arm corresponds to at least one parasitic helical arm. Each main helical arm is arranged in parallel with and is spaced with its corresponding parasitic helical arm. A first terminal of each main helical arm is electrically connected to a first terminal of the corresponding parasitic helical arm. A second terminal of the main helical arm and a second terminal of the parasitic helical arm are both in a floating state, and a length of the parasitic helical arm is greater than a length of its corresponding main helical arm.

Abstract: The embodiment of the present disclosure provides a recovery device for oil spilling on water, a control method thereof, and a recovery vessel. The recovery device includes a casing, a control center, a variable pressure airbag, an oil detector, an isolation layer, a water suction pump, and a drain pipe. The casing is of a hollow structure, the hollow structure is used to accommodate an oil-water mixture and used as a temporary oil collection tank, the upper part of the casing is provided with an oil-water mixture inlet, the bottom of the casing is provided with a drain port, and the side wall of the casting is provided with an oil suction port. The variable pressure airbag is arranged outside the casing, and the variable pressure airbag is configured to adjust buoyancy of the recovery device. The water suction pump is configured to pump out water in the casing and discharge water to a water environment outside the casing through the drain pipe.

Abstract: The embodiments of the present disclosure provide a detachable anti-vibration sealing protection device for a pipe flange. The protection device includes a casing, wherein left and right end surfaces of the casing have through holes for the pipeline to pass through, and the casing has an accommodation cavity for placing the flange; a first shock absorption assembly for radial shock absorption of the flange; and a second shock absorption assembly which is installed in a one-to-one correspondence with the flange and is configured for axial shock absorption of the corresponding flange. The first shock absorption assembly and the second shock absorption assembly are installed in the accommodation cavity.

Abstract: A sea surface oil recovery device is provided, which comprises a storage cabin, an oil-water separation system and an oil-water collection system arranged on the storage cabin. The storage cabin is provided with an oil storage cabin, a water storage cabin, a separation cabin and a gas storage cabin which are separated from each other, and the storage cabin is provided with a water pipe for connecting the water storage cabin with the outside of the storage cabin. The oil-water separation system comprises a molecular semipermeable membrane for separating oil and water and a water suction pipe, wherein the molecular semipermeable membrane is arranged between the separation cabin and the water storage tank and connects the separation cabin with the water storage tank; the water suction pipe is arranged between the oil storage cabin and the separation cabin and connects the oil storage tank with each other.

Abstract: The present invention discloses a compound fluorine-free foam extinguishing agent and a preparation method therefor, comprising components of the following parts by weight: 6-8 parts of alkyl glycoside, 10-14 parts of polysiloxane quaternary ammonium salt, 0.5-1 part of silicon dioxide and 60-65 parts of water. The compound fluorine-free foam extinguishing agent prepared by the present invention has a high stability, a high expansion, an obvious fire extinguishing effect and a higher environment-friendliness. The polysiloxane quaternary ammonium salt contains hydrophobic polysiloxane long chains, has a high temperature resistance, and collaborates with the alkyl glycoside to be adsorbed on the surface of silicon dioxide particles, which improves the stability of the silicon dioxide in a solution and reduces the surface tension of the solution.

Abstract: The embodiments of the present disclosure provide a method and a system for leakage analysis of an urban pipeline, and a storage medium. The method includes: obtaining sample signal data of an original signal and a corresponding first waveform diagram; obtaining at least two first components and a second component by processing the sample signal data based on preset iteration operations; determining a mutual information entropy of two adjacent first components in the at least two first components; determining high-frequency signal data of the original signal based on the mutual information entropy; determining an effective characteristic signal and a corresponding second waveform diagram based on the high-frequency signal data and the sample signal data; determining whether the urban pipeline leaks based on the second waveform diagram; and in response to that the urban pipeline leaks, determining a leakage aperture of the urban pipeline based on the effective characteristic signal.

Abstract: The embodiments of the present disclosure provide an adaptive sealing device for pipeline porous leakage. The device includes a pressure protection device and an encircling sealing rubber cover. The pressure protection device is used to pressurize and seal the pipeline based on the encircling sealing rubber cover. The device further includes a control mechanism connected with the pressure protection device for adjusting the sealing pressure of the pressure protection device on the pipeline. The device further includes an anti-retraction mechanism connected with the pressure protection device and the control mechanism for limiting the pressure protection device and/or the control mechanism.

Abstract: The embodiments of the present disclosure provide a detachable anti-vibration sealing protection device for a pipe flange. The protection device includes a casing, wherein left and right end surfaces of the casing have through holes for the pipeline to pass through, and the casing has an accommodation cavity for placing the flange; a first shock absorption assembly for radial shock absorption of the flange; and a second shock absorption assembly which is installed in a one-to-one correspondence with the flange and is configured for axial shock absorption of the corresponding flange. The first shock absorption assembly and the second shock absorption assembly are installed in the accommodation cavity.

Abstract: A sea surface oil recovery device is provided, which comprises a storage cabin, an oil-water separation system and an oil-water collection system arranged on the storage cabin. The storage cabin is provided with an oil storage cabin, a water storage cabin, a separation cabin and a gas storage cabin which are separated from each other, and the storage cabin is provided with a water pipe for connecting the water storage cabin with the outside of the storage cabin. The oil-water separation system comprises a molecular semipermeable membrane for separating oil and water and a water suction pipe, wherein the molecular semipermeable membrane is arranged between the separation cabin and the water storage tank and connects the separation cabin with the water storage tank; the water suction pipe is arranged between the oil storage cabin and the separation cabin and connects the oil storage tank with each other.

Abstract: Disclosed is an urban non-metallic pipeline leakage location method, the method comprise the following steps: determining whether leakage occurs in a pipeline through numerical simulation law analysis or a Markov chain-based flow analysis method; for a leaking pipeline, establishing an inverse-transient control equation for non-metallic pipeline gas leakage, and obtaining pressure and flow rate data of each measuring point in different periods of time through experiments and substituting the data into the control equation to analyze experimental data; and defining a nonlinear programming problem of an objective function with a least squares criterion, and applying a sequential quadratic programming method to minimize the objective function, so as to determine the size and position of the leakage.

Abstract: Disclosed is a method for predicting corrosion and spontaneous combustion of sulfur-related petrochemical equipment. The method solves the issues in the existing techniques that includes narrow predicting range, high workload in installation and maintenance, and time lag in predicting corrosion and spontaneous combustion inside equipment. The method comprises a step of a dual index system prediction, which includes a step of monitoring a temperature and a step of detecting SO2 gas generated by spontaneous combustion. The time when spontaneous combustion occurs can be accurately calculated by using a fitted quantitative relationship formula generated by the spontaneous combustion of corrosion products. The method has a low Labor cost. The method has a low labor cost and, does not require on-site gas detection to be carried out by means of manual detection, which both reduces the cost and ensures the detection accuracy.

Abstract: Disclosed is an urban non-metallic pipeline leakage location method, the method comprise the following steps: determining whether leakage occurs in a pipeline through numerical simulation law analysis or a Markov chain-based flow analysis method; for a leaking pipeline, establishing an inverse-transient control equation for non-metallic pipeline gas leakage, and obtaining pressure and flow rate data of each measuring point in different periods of time through experiments and substituting the data into the control equation to analyze experimental data; and defining a nonlinear programming problem of an objective function with a least squares criterion, and applying a sequential quadratic programming method to minimize the objective function, so as to determine the size and position of the leakage.

Abstract: The disclosure provides a pipeline leak detection device and a leak detection method based on the variational mode decomposition optimized by the particle swarm (PSO-VMD). The acoustic emission signals with leakage and without leakage are collected by the acoustic emission system. Since the decomposition result of the traditional VMD depends on the selection of the parameter preset scale K and the penalty coefficient ?, the PSO is employed to obtain the optimal parameters of the VMD. The optimized parameters are input into VMD to decompose the original signals, and then K intrinsic mode functions (IMFs) can be obtained. After the signal reconstruction for de-noising, based on the energy ratio, the time-domain features are extracted and the support vector machine (SVM) is used to detect the leak.

Abstract: A helical antenna, including a printed circuit board and a radiating body provided above the printed circuit board. The radiating body includes at least one main helical arm and at least one parasitic helical arm. Each main helical arm corresponds to at least one parasitic helical arm. Each main helical arm is arranged in parallel with and is spaced with its corresponding parasitic helical arm. A first terminal of each main helical arm is electrically connected to a first terminal of the corresponding parasitic helical arm. A second terminal of the main helical arm and a second terminal of the parasitic helical arm are both in a floating state, and a length of the parasitic helical arm is greater than a length of its corresponding main helical arm.

Abstract: Disclosed is a method for predicting corrosion and spontaneous combustion of sulfur-related petrochemical equipment. The method solves the issues in the existing techniques that includes narrow predicting range, high workload in installation and maintenance, and time lag in predicting corrosion and spontaneous combustion inside equipment. The method comprises a step of a dual index system prediction, which includes a step of monitoring a temperature and a step of detecting SO2 gas generated by spontaneous combustion. The time when spontaneous combustion occurs can be accurately calculated by using a fitted quantitative relationship formula generated by the spontaneous combustion of corrosion products. The method has a low Labor cost. The method has a low labor cost and, does not require on-site gas detection to be carried out by means of manual detection, which both reduces the cost and ensures the detection accuracy.