63results about How to "Save on preprocessing steps" patented technology

The invention discloses a dynamic time sequence convolutional neural network-based license plate recognition method. The method comprises the following steps of: reading an original license plate image; carrying out license plate angle correction to obtain a to-be-recognized license plate image; inputting the to-be-recognized license plate image into a previously designed and trained convolutionalneural network so as to obtain a feature image and time sequence information, wherein the feature image comprises all the features of the license plate; and carrying out character recognition, inputting the feature image into a convolutional neural network of a long and short-term memory neural network layer on the basis of time sequence information of the last layer so as to obtain a classification result, and carrying out decoding by utilizing a CTC algorithm so as to obtain a final license plate character result. According to the method, vision modes are directly recognized from original images through using convolutional neural networks, self-learning and correction are carried out, the convolutional neural networks can be repeatedly used after being trained for one time, and the timeof single recognition is in a millisecond level, so that the method can be applied to the scenes needing to recognize license plates in real time. The dynamic time sequence-based long and short-termneural network layer is combined with CTC algorithm-based decoding, so that recognition error problems such as leak detection and repeated detection are effectively avoided, and the algorithm robustness is improved.

The invention provides an interface device for on-line coupling of LC-GC / MS and a method for analyzing fragrant components in tobaccos by utilizing the device. According to the method, reverse blowing gas can be provided through switch of a gas switch valve, during sample injection, the reverse blowing gas is discharged form a GC flow-splitting port against the GC carrier gas direction through a tee coupling, therefore solvents can be transferred out completely, solutes are reserved in a TenaxTA absorbent in a PTV liner tube, thermal desorption is performed on a PTV injection port after the solvents are transferred completely, the GC carrier gas shifts cut fractions to be tested into a GC column for separation, effects on an MS vacuum system due to the fact the solvents enter the GC column are effectively avoided, and large volume injection can be achieved.

The invention provides an etherification method for producing clean gasoline, hydrocarbon etherification raw materials are mixed with fatty alcohol, which are put into an etherification reactor for contacting and being in reaction with the etherification catalyst, without separation, the reaction products are directly put into a catalytic cracking stabilizer for fractionation, separated liquefied gas can be got from the top of the tower, while stabilized gasoline containing ether compound is got from the bottom of the stabilizer, the etherification catalyst is chosen from one or a plurality of strong acid cation exchange resin, zeolite catalyst and heteropoly acid catalyst. The method effectively combines the hydrocarbon etherification and existing catalytic cracking stabilizing system together, fully makes use of the catalytic cracking stabilizing system to separate the etherification reaction products, which not only effectively reduces the energy consumption and operating cost, but also gets the stabilized gasoline with low content of olefin, the high octane value and qualified vapor pressure.

The invention discloses a pointer type instrument reading identification method based on deep learning. The method comprises the following steps: identifying a dial area in a to-be-identified instrument picture through a first deep network model; intercepting an area where a dial plate of the instrument to be identified is located from the picture; identifying a circle center coordinate, each scale line number coordinate, a semi-pointer tip coordinate and coordinates of two scale line numbers located at two sides of the pointer in the dial plate through a second depth network model; respectively intercepting the areas where the two scale line numbers are located from the intercepted picture of the dial area of the instrument to be identified; and identifying numerical values of the two scale line numbers through a third depth network model, and reading by adopting an angle method. According to the pointer type instrument reading identification method based on deep learning, the readingnumbers of multiple types of pointer type instruments can be identified at the same time, and the reading efficiency is higher.

The invention discloses a system to make pentose solution through serially continuing hydrolysis for agricultural and forestry chemical waste, which contains N-grade of mutually serial hydrolytic units, wherein N is integral, which is not less than 2; each grade of hydrolytic unit includes mutually serial hydrolytic device and solid-liquid separating device to hydrolyze the agricultural and forestry chemical waste and separate liquid and solid of the hydrolyzed mixture to generate the hydrolytic acid liquid and solid with pentose. The system makes the entire technique realize automation with high conversion rate of agricultural and forestry chemical waste and high pentose solution density, which produces the solid material as raw material cellulose of alcohol.

The invention relates to hydrothermal carbon spheres for supporting nanosilver by using a one-step method and a preparation method and application of the hydrothermal carbon spheres. The preparation method comprises the following steps: removing impurities from whole collected biomass components, washing, drying, preparing fine granules under the external mechanical actions of a crushing machine and a ball mill, dissolving the whole biomass components into a sodium hydroxide / urea system, after the solution is dissolved, dropping a prepared silver ammonia solution, uniformly mixing, pouring theuniformly mixed solution into a high-temperature high-pressure reaction kettle, carrying out a hydrothermal reaction, and after the hydrothermal reaction is completed, carrying out centrifugation, washing, ultrasonic treatment, centrifugation and freeze drying on the solution, thereby obtaining the nanosilver supported hydrothermal carbon spheres finally. By adopting the hydrothermal carbon spheres, the defects that nanosilver is liable to aggregate, instable and too rapid in leakage can be alleviated, the application range of the hydrothermal carbon spheres as a nanosilver carrier is widened, and whole biomass components such as agriculture and forestry biomass wastes can be sufficiently utilized.

The invention discloses a method for activating a carbon fiber by colloid copper and preparing a chemical plating copper-nickel duplex metal layer by one-step. According to the method for activating the carbon fiber by the colloid copper and preparing the chemical plating copper-nickel duplex metal layer by one-step, a colloid copper activating method is adopted to replace traditional palladium, cheap material copper sulfate is adopted, an optimized activating solution has good stability and high activation properties, and a composite plate formed during subsequent chemical plating is even andcontinuous; in addition, compared with a two-step method of nickel plating after copper plating, a one-step method of chemically plating the copper-nickel duplex metal layer reduces the using amountof copper sulfate and nickel sulfate, and the one-step method is faster and more efficient; and sodium monophosphate is used for replacing formaldehyde as a reducing agent, and environmental pollutionand harm to human bodies are reduced.

The invention provides a lateral line etherification method which integrates a catalytic cracking absorbing stabilizing system; hydrocarbon etherification raw materials are sent into a catalytic cracking stabilizer for fractionation, the catalytic cracking stabilizer is provided with a lateral line discharge hole from the position about 95 percent of the height to about 50 percent of the height of the stabilizer, the liquid material and fatty alcohol from the lateral line discharge hole are mixed together to be sent into an etherification reactor for reaction with the effect of etherification catalyst, the reaction products are sent into the stabilizer for fractionation without separating from the lateral line feeding hole under the lateral line discharge hole, separated liquefied gas can be obtained from the top of the stabilizer, while stabilized gasoline containing ether compound is obtained from the bottom of the stabilizer. The method fully makes use of the mass transfer and heat transfer conditions of the catalytic cracking stabilizing system, which does not only reduce the energy and material consumption, but also obtains the stabilized gasoline with low content of olefin, the high octane value and qualified vapor pressure.

The invention relates to a <18>O on-line marked protein quantitative analysis platform, and an operation method thereof. The <18>O on-line marked protein quantitative analysis platform is a system integrating protein on-line enzymolysis, <18>O on-line marking and polypeptide separation and detection. The <18>O on-line marked protein quantitative analysis platform comprises an injection pump, a sampling needle, a column oven, an enzyme reactor, a switch valve, a peptide fragment capture column, a liquid phase chromatography pump, a polypeptide separation column and a mass spectrometry detector. A protein sample is firstly loaded to the enzyme reactor through the injection pump to carry out incubation; <18>O marking can be carried out at the same time with enzymolysis; and the <18>O marked peptide fragment after enzymolysis is enriched on-line and transferred into the polypeptide separation column for further separation, and finally is detected by the mass spectrometry detector. The <18>O on-line marked protein quantitative analysis platform integrates the protein on-line enzymolysis, <18>O on-line marking and polypeptide separation.

The invention discloses low-cost medical breathable tape and a manufacturing method thereof. The low-cost medical breathable tape comprises a medical hot-melt pressure-sensitive adhesive coating, a base material layer and a waterproof and moisture permeable coating, wherein the medical hot-melt pressure-sensitive adhesive coating, the base material layer and the waterproof and moisture permeable coating are arranged in sequence from top to bottom, netty air holes are formed in the base material layer, and the medical hot-melt pressure-sensitive adhesive coating and the waterproof and moisture permeable coating are attached to the base material layer. The manufacturing method of the low-cost medical breathable tape comprises the steps of (a) preparing waterproof slurry for use, (b) enabling the back side of the breathable base material layer to be coated with separant and the waterproof slurry prepared in the step (a) and drying the separant and the waterproof slurry, and (c) adhering medical hot-melt pressure-sensitive adhesive to the front side of the breathable base material layer and carrying out rewinding and cutting after the medical hot-melt pressure-sensitive adhesive is dried. The low-cost medical breathable tape and the manufacturing method thereof have the advantages that preprocessing steps of base materials are simplified, no intermedium is used for colloid transferring, and the production is safe and free of pollution; the production cycle is short and cost is effectively reduced; finished low-cost medical athletic tape is used for binding and fixing, breathability and flatness are good, and using is more convenient.

An inorganic phosphatic crystal material has a two-dimension electronegativity skeleton structure formed by four elements of aluminium, oxygen, phosphor and fluorine. Sodion and / or lithium ion is disposed in the interlayer and pore canals of the two-dimension electronegativity skeleton. The expression of the material is Na5-XLiXAl3(PO4)6F6. A preparation method of the material provided by the invention comprises the following steps of: mixing an aluminium source, phosphatic of sodium and / or phosphatic of lithium, fluoride and deionized water according to the mol ratio of 3-5: 6-10: 6-10: 20-100, and stirring to form an initial gel; adjusting pH value of the initial gel obtained from step a to 8-9 by the use of a sodium hydroxide solution and / or a lithium hydroxide solution; and hydrothermally crystallizing the gel obtained from step b at the crystallization temperature of 120-160 DEG C for 12-90 hours so as to obtain the inorganic phosphatic crystal material. By the adoption of the inorganic phosphatic crystal material provided by the invention, the performance of solid electrolyte and an inorganic ion exchanger is raised.

The invention discloses an abnormal brain connection prediction system, method and device and a readable storage medium, and the method comprises the steps: automatically extracting high-order correlation features in different modes and high-order complementary features between different modes through a deep learning method; and realizing the analysis of abnormal connection of the multi-modal brain network and prediction of different cognitive diseases through an adversarial training method. The method solves the problem that an existing method cannot accurately evaluate the change rule of brain structural morphology and functional connection. According to the method, a prior knowledge guide model is used for learning interpretable characterization, the consistency of different modal characterization distribution is restrained through a paired collaborative discriminator, and then brain graph data is reconstructed for feature codes through a reverse generator and a decoder; and finally, inter-modal and intra-modal high-order correlation features are extracted through a hypergraph perception fusion module, and an adversarial loss function, a reconstruction loss function and a classification loss function are set to guide model learning so as to achieve the purpose of mining the abnormal brain connectivity of the Alzheimer's disease.

The invention relates to a chiral LC-MS (liquid chromatograph-mass spectrometer) / MS high-throughput detection method for pantoprazole in human plasma. The method includes the steps: taking plasma samples to be detected to mix into internal standard solution; adding 500muL internal standard solution into the plasma samples to serve as protein precipitators by the aid of a pretreatment method of a protein precipitation method; taking liquid supernatant after vortex and centrifugation to obtain samples to be detected; performing LC-MS analysis. The method has the advantages that the method meets analysis requirements of large-batch clinical samples and is simple to operate, short in pretreatment time and chromatographic analysis time and suitable for pretreatment of high-throughput samples as compared with the prior art.

The invention discloses a platinum-carbon catalyst, a preparation method thereof and an application of the platinum-carbon catalyst in a cathode catalyst of a fuel cell, and the preparation method comprises the following steps: 1) preparing an aqueous solution of sugar, adjusting the pH value to 5-9, then carrying out hydrothermal carbonization reaction by adopting the solution, and drying to obtain a carbon carrier material; 2) preparing a mixed solution of glucose and a platinum precursor, and heating the mixed solution; 3) adding a dispersion liquid of a carbon carrier material, adjusting the pH value to 3-10, heating, and reacting; 4) cooling and separating a reaction product to obtain a platinum-carbon catalyst precursor; and 5) calcining to obtain the platinum-carbon catalyst. According to the preparation method, cheap saccharides are used as precursors to prepare the carbon carriers, pretreatment is not needed, nano platinum particles can be well dispersed, and the catalytic performance of the prepared catalyst on oxygen reduction is superior to that of a commercial platinum-carbon catalyst. Moreover, the method is green in reaction, simple in preparation process and suitable for industrial production, and has a wide application prospect in the field of fuel cell catalysts.

The invention discloses a method for increasing the yield of clean fuel oil. The method comprises the following steps: subjecting ethylene tar to fractionation so as to obtain a light fraction and a heavy fraction, mixing the heavy fraction with a conventional coking raw material, then subjecting the mixture to a delay coking treatment so as to obtain a coking product, transporting the coking product and a C9 component from an ethylene device into a coking distillation tower, carrying out a distillation treatment so as to obtain a coking gasoline fraction and a coking diesel oil fraction, carrying out a hydro-refining treatment on the obtained coking gasoline fraction, mixing the coking diesel oil fraction with the ethylene tar light fraction, then subjecting the mixture to a hydro-treatment, and separating the products so as to obtain a gasoline product and a diesel oil product. The method fully utilizes the ethylene tar and C9 fraction, improves the utilization rate of by-products of ethylene device, prominently improves the yield and quality of lightweight fuel oil, and is beneficial for yield increasing of high quality clean fuel oil for refineries.

The invention provides an etherification method which integrates a catalytic cracking absorbing stabilizing system; after being mixed with fatty alcohol, hydrocarbon etherification raw materials are sent into a catalytic cracking stabilizer; during the reaction period in the catalytic cracking stabilizer, the materials are in contact with the etherification catalyst for reaction and fractionation, separated liquefied gas can be obtained from the top of the stabilizer, while stabilized gasoline containing ether compound is obtained from the bottom of the stabilizer, the etherification catalyst is chosen from one or a plurality of strong acid cation exchange resin, zeolite catalyst and heteropoly acid catalyst. The method fully makes use of the mass transfer and heat transfer conditions of the catalytic cracking stabilizing system, which does not only reduce the energy and material consumption, but also obtains the stabilized gasoline with low content of olefin, high octane value and qualified vapor pressure; the method has great suitability towards the characteristic that domestic catalytic gasoline has high content of olefin, which can provide more operating flexibility for refineries to produce gasoline of high index.

The invention provides a device for treating oily wastewater based on photocatalytic-oxidation composite diatomite-based nano-ceramics. The device comprises oil-water separating, filtering, adsorbingand photocatalytic treating modules; and during treatment, the modules act simultaneously, treatment steps, which originally need multiple steps and a long time, are integrated and completed in one device, and the treatment effect on the oily wastewater is good. The invention further provides a method for treating the oily wastewater based on the photocatalytic-oxidation composite diatomite-basednano-ceramics.

The invention provides a hydrocarbon etherification method which is combined with a catalytic cracking absorbing stabilizing system; after being mixed with the chosen fatty alcohol, the hydrocarbon etherification raw materials are sent into a pre-etherification reactor, and reacts with a pre-etherification catalyst in a contact way; without separation, the reaction products are directly put into catalytic cracking stabilizer after being mixed with the chosen fatty alcohol; during the reaction period in the catalytic cracking stabilizer, the reaction products react in contact with the etherification catalyst for fractionation, separated liquefied gas can be obtained from the top of the stabilizer, while stabilized gasoline containing ether compound is obtained from the bottom of the stabilizer. The method fully makes use of the mass transfer and heat transfer conditions of the catalytic cracking stabilizing system, which does not only reduce the energy and material consumption, but also obtains the stabilized gasoline with low content of olefin, high octane value and qualified vapor pressure; the method has great suitability towards the characteristic that domestic catalytic gasoline has high content of olefin, which can provide more operating flexibility for refineries to produce gasoline of high index.

The invention discloses a PtNi nano-alloy electrochemical sensor for detecting dopamine. The PtNi nano-alloy electrochemical sensor is characterized in that 4 microliters to 5 microliters of a binary PtNi nano-crystal ethanol solution is coated on a glassy carbon electrode to form a modified electrode PtNi / GCE; meanwhile, the modified electrode PtNi / GCE, a silver / silver chloride electrode and a platinum plate electrode form a three-electrode system; the dopamine is directly detected by utilizing an electrochemical working station. The electrochemical sensor disclosed by the invention has special sensitivity and stability on the dopamine and has relatively low detection limit, relatively wide detection range and good anti-interference property.

The invention discloses a micron-sized zone sampling method and device suitable for a capillary tube. The sampling device comprises a capillary tube, sampling plates, a displacement control mechanism and a capillary tube cleaning mechanism, wherein one end of the capillary tube is the sampling end; the sampling end is polished to be flat or sharp, and is perpendicularly pointed to the sampling plates; the other end of the capillary tube is connected with the capillary tube cleaning mechanism; the sampling plates are placed on the displacement control mechanism; the displacement control mechanism is used for controlling the sampling plates to horizontally move in the long axis or short axis direction of the capillary tube. The sampling method utilizes the in situ dissolution and diffusion principle to transfer sample components, can be applied to in situ direct sampling of the liquid sample, the solid sample and the transition state sample of the solid sample, and can reduce the sample pretreatment steps; the sampling zone is micron-sized, and the sampling method is urgently needed by the short capillary tube separation technology; the sampling is simple and convenient to control, and the device is easy to design and manufacture.

The invention provides a speech recognition method based on a time domain convolution coding and decoding network, and the method comprises the steps: inputting audio information, obtaining audio features which comprise a Mel-frequency cepstrum coefficient and a linear prediction cepstrum coefficient, inputting the audio features into a pre-constructed neural network model to obtain a time sequence feature sequence, encoding and decoding the time sequence characteristic sequence through a time domain convolution network to obtain a group of output sequences, and obtaining a prediction result according to the output probability of each element in the output sequence and a preset mapping rule of the output sequence and a preset label sequence, the problem of speech recognition delay can be effectively solved.

The invention provides an industrial wastewater treatment system based on a low-temperature mass transfer concentration technology. Waste liquid is subjected to low-temperature mass transfer and carrier gas extraction in the device, the mass transfer unit can transfer 80% of moisture in the waste liquid into air under the driving of low-temperature mass transfer power by utilizing the water vaporpartial pressure difference between the surface of a solution and circulating air, and the moisture separation unit separates out condensed water from saturated humid air in an evaporation section ofa heat pump; and water and waste liquid are concentrated and separated, and no waste is discharged except the separated wastewater concentrated solution in the operation process.

The invention relates to the technical field of electrochemical detection, in particular to a working electrode biological reactant and application and an electrode-type test strip thereof. The working electrode biological reactant comprises ascorbic acid oxidase, peroxidase and a reductive electronic mediator. The electrode-type test strip provided by the invention can accurately determinate the content of ascorbic acid in whole blood and can avoid interference of endogenous dehydrogenized ascorbic acid in serum.

The invention provides a preparation method of isocyanurate polyether polyol. The preparation method comprises the steps: (1) mixing an initiator tris(2-hydroxyethyl)isocyanurate with a catalyst so asto obtain an initial mixture; (2) adding an epoxy compound to the initial mixture dropwise, and performing heating for a solid-liquid reaction so as to obtain a primary reaction product; (3) adding the epoxy compound to the primary reaction product continuously, and performing a gas-liquid reaction so as to obtain a secondary reaction product; and (4) cooling the secondary reaction product so asto obtain the isocyanurate polyether polyol, wherein the temperature of the solid-liquid reaction is not more than 110 DEG C, and darker color, caused by local overheating, of the final product is avoided through control on the temperature of the solid-liquid reaction at not more than 110 DEG C, so that the reaction is safe and controllable, and the energy consumption and cost are reduced.

The invention discloses an aqueous coating for an automobile plastic part. The aqueous coating comprises the following components in parts by weight: 50-70 parts of an aqueous polyacrylic acid dispersant, 2-4 parts of a dispersant, 3-5 parts of a leveling agent, 0.5-1 part of a defoaming agent, 3-5 parts of filming aids, 5-8 parts of nano titania, 15-20 parts of coarse whiting, 5-8 parts of precipitated barium sulphate of 1500 meshes, 0.1-0.3 part of rheologic aids, 1-3 parts of a water-soluble titanate coupling agent, 1-3 parts of a flash-rust inhibitor, 0.5-1 part of a thickening agent, 70-90 parts of an isocyanate curing agent and 15-25 parts of a solvent. Th invention further discloses a preparation method of the aqueous coating. The aqueous coating disclosed by the invention is a sealed polyurethane coating which can be applied to a plastic part after common pretreatment, and a coating layer is high in acid-alkali resistance, corrosion resistance and tension strength and excellentin adhesion property.

The invention discloses a pretreatment method and a detection method of amoxicillin, penicillin G and penicillin V. The pretreatment method comprises the following steps that 1, a mixture of a sample to be detected and acetonitrile is centrifuged to collect supernatant, and the sample to be detected is a milk product which does not contain solid particles; 2, the supernatant is loaded to an activated Oasis PRiME HLB solid-phase extraction column, and effluent is collected. The pretreatment method is fast, simple, economical, reliable, capable of effectively extracting components to be detected and removing the influence of a complex matrix, and beneficial for fast detecting the sample to be detected. While the high extraction rate is kept, less organic solvent is used and discharged, loss of the organic solvent is reduced, environment is protected easily, the pretreatment steps are reduced, time is saved, energy consumption is reduced, and the detection method is fast, simple and high in precision and accuracy, and has high application value.

The invention relates to a method for preparing special corn flour for fermentation. The method comprises the steps: crushing no-mildew corn grains, screening with a screen with the mesh size of 40 meshes, and fetching screen underflow, so as to obtain corn flour; mixing the corn flour and an industrial enzyme preparation, mixing uniformly, and then, feeding the mixture into a twin-screw extrusion and bulking machine for extruding and bulking; drying extruded and bulked raw materials so as to enable the moisture content of the raw materials to be lower than 8-12%; crushing the dried raw materials by using a pulverizer, and controlling the temperature to be below 80 DEG C during crushing, thereby obtaining the special corn flour for fermentation. The method disclosed by the invention is simple in process, convenient in operation, easy in automation and low in preparation cost; the special corn flour for fermentation, prepared by the method, has the advantages that a pretreating step for industrial fermentation enterprises during use is avoided, the corn flour utilization efficiency of microorganisms is increased, and the comprehensive economic benefits of the industrial fermentation enterprises are increased.

The invention provides a modularized electrolytic seawater dehydrogenation module with a dehydrogenation function and an antifouling device, and belongs to the technical field of electrochemical electrolysis antifouling. The hydrogen elimination module is based on a two-step hydrogen elimination technology, comprises a gas-liquid separation technology for separating hydrogen from seawater and a hydrogen elimination technology for eliminating hydrogen by using a platinum-palladium catalyst, and mainly comprises a gas-liquid separation unit, a hydrogen elimination reactor unit, a detection unit and a cooling unit, the device is used for separating and eliminating H2 generated by electrolysis of a cathode in the seawater electrolysis process. Wherein the gas-liquid separation unit adopts a physical method, and H2 is separated from a seawater medium under the action of centrifugal force or gravity; wherein the dehydrogenation reactor unit adopts a platinum-palladium catalyst to enable H2 and O2 to rapidly react to generate H2O, and the H2O generated by the reaction is guided back into a seawater pipeline; wherein the detection unit adopts an H2 sensor to monitor the concentration of residual H2 so as to ensure that the absorption rate of H2 meets the requirement.

The invention discloses a system to make pentose solution through serially continuing hydrolysis for agricultural and forestry chemical waste, which contains N-grade of mutually serial hydrolytic units, wherein N is integral, which is not less than 2; each grade of hydrolytic unit includes mutually serial hydrolytic device and solid-liquid separating device to hydrolyze the agricultural and forestry chemical waste and separate liquid and solid of the hydrolyzed mixture to generate the hydrolytic acid liquid and solid with pentose. The system makes the entire technique realize automation with high conversion rate of agricultural and forestry chemical waste and high pentose solution density, which produces the solid material as raw material cellulose of alcohol.

The invention provides a steel sheet pile cofferdam water stop belt. The water stop belt comprises an elastic outer casing and magnetic columns. The elastic outer casing is provided with a hollow portion, and the plurality of the magnetic columns are disposed in the hollow portion. A water stopping process is further provided for the water stop of a steel sheet pile cofferdam. The steel sheet pilecofferdam water stop belt is embedded in a lock gap of the adjacent steel sheet piles to prevent water outside the cofferdam from permeating the cofferdam. The water stop belt has advantage that a prefabricated belt material replaces the original mixture of multiple materials, the pretreatment steps are reduced, and the installation time is saved; moreover, due to the built-in magnetic columns ofthe water stop belt, mutual suction force exists between the steel sheet piles, time and labor are saved during installation, and the cofferdam is not easily affected by the water flow or loosened when maintained.