42results about How to "Unstable" patented technology

The invention discloses a combination forecast modeling method of wind farm power by using gray correlation analysis, belonging to the technical field of wind power generation modeling. In particular, the invention is related to a weighted combination forecast method of wind power based on a least square support vector machine and an error back propagation neural network. The forecast method comprises that forecasted values of wind speed and wind direction are acquired in advance from meteorological departments while real-time output power is acquired from a wind farm data acquiring system; that the forecasted values of wind speed and wind direction and the real-time output power are inputted into a data processing module for data analyzing extraction and data normalization, and then normalized data is loaded to a database server; processed data in the database server is extracted by a combination forecast algorithm server to carry out model training and power forecast, and the wind farm sends running data to the data processing module in real time to realize rolling forecasting. The method of the invention achieves the goal of combination forecast of wind farm output in a short time. The method not only maximally utilizes advantages of two algorithms but also increases forecast efficiency by saving computing resources and shortening computing time.

The invention discloses a self-adaptive threshold value moving object detection method based on a codebook background model, which belongs to the technical field of intelligent video monitoring. The method comprises the following steps of (1) classifying an inputted video image sequence into a training set and a detection result set, and creating an initial codebook background model for the inputted training set through a self-adaptive threshold value method; (2) purifying and optimizing the created initial codebook background model through a time filtering way; (3) applying the purified codebook background model to the foreground detection, and subtracting the codebook background model adopting the front n frames of image which is used as a training sample as the training set by the subsequently inputted video image sequence; and (4) binarizing the obtained differential image, and utilizing the binary image as a final detection result image. By adopting the method, the threshold value can be self-adaptively adjusted, so that compared with the traditional detection method, the method has the advantages that a better detection result can be obtained, and the accuracy is high.

The invention discloses a track network's crowded bottleneck identification method based on percolation theory. The method comprises the following steps: a) abstracting a track network as a directed topological map; b) selecting the interval full-load rate as the state characteristic index; c) according to the percolation theory, constructing a dynamic network or rather, giving a specific full-load rate value l at each moment wherein if the interval full-load rate is greater than the specific value of l, then deleting the interval; and keeping the interval if otherwise; d) for the same moment, changing the value l with the result of changing the network connection; based on the percolation theory, when the scale of the second largest communication graph SG in the network reaches the maximum, naming the corresponding value l as the threshold value; and e) determining that the interval set deleted at the threshold value extracted at value l as the possible bottleneck set; changing the interval state of the interval set; and if the changed of the interval can improve the network condition, then, determining the interval as the crowded bottleneck. According to the method of the invention, it is possible to perform dynamic identification to a crowded bottleneck so as to facilitate the adjustment of the bus times and intervals to start the buses by the operation and management personnel and to provide high quality service to passengers accordingly.

The invention relates to a petrifaction heat insulated tank which comprises a tank body. The petrifaction heat insulated tank is characterized by also comprising a heat collecting pipe, fins, a keel, a transparent protection plate, a heat insulating layer, a water inlet and a water outlet, wherein the heat insulating layer is adhered on the outer wall of the tank body and externally provided with the heat collecting pipe; the fins are arranged outside the heat collecting pipe, and the transparent protection plate is covered on the outer layer of the fins and connected with the tank body through the keel; and the heat collecting pipe is connected between the water inlet and the water outlet. The invention scientifically utilizes solar resources, realizes the effects of heating, heat insulating, cooling and cold insulating of the tank, achieves the purposes of saving energy and reducing emission, realizes the integral and scientific combination of a tank building and solar energy utilization, has the advantages of no land space occupation, simple construction, low manufacture cost and safe and reliable operation, and not only is suitable for centralized mounting and central control of a petrifaction mixed tank area, but also can independently use a single tank so as to be convenient for scientific and reasonable uniform operation.

The invention relates to a level set target tracking method based on a convolutional neural network, and belongs to the technical field of target tracking and video processing. The level set target tracking method based on a convolutional neural network includes the following steps: 1) utilizing the first frame and the first frame standard target contour of video input to initialize an Adaboost detection module; 2) calling a detection module to obtain the initial position and shape of an object in the subsequent video frame; 3) operating a level set method tracking module on the above basis, and accurately segmenting the object contour; and 4) by means of the result of the step 3, distinguishing the foreground / background, and updating a weak classifier of the detection module. For the level set target tracking method based on a convolutional neural network, the utilization method of convolutional neural network characteristics can make a preferable distinction on the foreground / background so as to improve the detection accuracy and improve the overall target tracking effect; and the level set target tracking method based on a convolutional neural network can balance performance andefficiency, and can obtain relatively excellent tracking effect at the same operating speed.

The invention discloses a traditional Chinese medicine composition for treating acne, its preparation method and its application. The composition comprises an active ingredient composed of nine medicines and a conventional pharmaceutical carrier, and the active ingredient is composed of the following ingredients : Salvia, Hedyotis diffusa, Pueraria, Angelica, Dandelion, Forsythia, Morus Alba, Loquat Leaf and Fritillaria. The composition of the present invention can be produced by conventional methods in the art, and can be made into various commonly used dosage forms, especially oral dosage forms, such as granules and the like. When the composition of the invention is used for clinical treatment of acne, it has remarkable curative effect and no toxic or side effect.

A multilayer composite comprises a printable facestock with a carrier sheet separably laminated directly to its top surface. The facestock is a dimensionally unstable and / or low flexural stiffness transparent film having a thickness not greater than about 4.0 mils. In subsequent processing, graphics are printed on the bottom surface of the facestock followed by the application of pressure sensitive adhesive and a release liner. The liner is removable, allowing the composite to be adhered to a substrate, with the graphics remaining beneath and protected by the facestock. The carrier sheet is separable from the top surface of the facestock, either before or following removal of the release liner.

The invention discloses a solar dehumidification system for an underground space. The solar dehumidification system comprises a solar heat utilization part, a concentrated solution regeneration part and an underground space dehumidification part. The solar heat utilization part comprises a dilute solution storage tank, a three-way reversing valve, a solar heat collector, a temperature controller and an air source heat pump hot water unit, wherein the solar heat collector is introduced into an open type pulsating heat pipe, so that the temperature of a dilute solution is increased, and water evaporation in the solution regeneration part is promoted; the concentrated solution regeneration part comprises a dehumidification solution regenerator, a first solution pump, a heat regenerator, an air cooler and a concentrated solution storage tank, and the solution concentration is increased by using a flash evaporation technology of liquid dehumidification; and the underground space dehumidification part comprises a second solution pump, a fan, a first temperature detector, a humidity detector, a film type dehumidifier, a third solution pump, a humidity controller and a second temperature detector, and the air humidity is reduced by using a film dehumidification technology. Therefore, the system not only realizes efficient pollution-free dehumidification of the underground space, but also can solve the problems that the regeneration concentration is low and the dehumidified air is easy to carry a dehumidification solution in a liquid solution dehumidification technology.

The invention belongs to the technical field of remediation of contaminated soil and particularly relates to a heavy-metal passivator produced by using a matrix. The heavy-metal passivator comprises the following ingredients in parts by weight: 30-40 parts of activated sludge biochar, 30-40 parts of kitchen waste humic acid, 5-10 parts of waste brewer's yeast, 5-10 parts of bacilli, 3-6 parts of reduced iron, 20-30 parts of modified attapulgite, 20-30 parts of modified montmorillonite and 20-30 parts of modified diatomite. The multielement efficient heavy-metal passivator is compounded by using a chemical modified passivator and a modified natural passivator, is applicable to compounded stabilization of a variety of heavy metals, is used for remedying heavy-metal contaminated lands into fertile farmlands and has a relatively high real value and a broad application prospect.

The invention discloses a method for modeling a gear grinding machine thermal error model based on a bidirectional LSTM network. The method comprises the following steps: 1) preprocessing original thermal error data; 2) randomly generating a whale population, and judging whether the initial position of the whale population exceeds a preset range or not; if yes, changing the initial position of the whale population into a boundary; if not, keeping the position of the whale population; 3) establishing a Bi-LSTM neural network; 4) mapping the position of the whale population into the batch size of the Bi-LSTM neural network and the number of neurons of a hidden layer; 5) inputting the preprocessed original thermal error data into the Bi-LSTM neural network, and taking MAE as the fitness of the whale optimization algorithm; 6) judging whether the MAE meets a preset requirement or not, if not, updating the position of the whale population, and if the fitness after updating is smaller than the optimal fitness before updating, determining the optimal position X * before updating; 7) judging whether the number of iterations reaches the maximum value or not, and if yes, terminating iteration; if not, making t to be equal to t + 1, and cycling the step 4) and the step 7); and 8) outputting the MAE.

The invention discloses a fire-proof plate and a preparation method thereof. The fire-proof plate comprises closed cell perlite, volcanic ash, cement, asbestos fibers, talcum powder, sodium bicarbonate, calcium bicarbonate, barium sulfate, aluminum oxide C and water. The preparation method of the fire-proof plate includes the steps: uniformly mixing the closed cell perlite, the volcanic ash, the cement, the asbestos fibers, the barium sulfate and the aluminum oxide C to obtain a solid mixture A; adding the talcum powder into the water, adding the calcium bicarbonate and the sodium bicarbonateafter homogenization, and uniformly mixing the talcum powder, the calcium bicarbonate and the sodium bicarbonate to obtain liquid B; adding the liquid B into the solid mixture A and uniformly stirringthe liquid B and the solid mixture A to obtain mixed slurry; pouring the mixed slurry into a mould and performing standing, foaming and curing to obtain the fire-proof plate. The fire-proof plate isgood in heat insulation effect and suitable for manufacturing a fire-proof and heat insulation layer of special equipment such as a safety box and an ATM (automatic teller machine) and can effectivelyinsulate high temperature.

The invention provides a steady-flow heat storage type hydraulic control compressed air energy storage system and method based on clean energy. The system comprises a steady-flow water pumping system, a compression heat storage and gas storage system, a water pushing power generation system and a comprehensive control system. The super capacitor in the steady-flow water pumping system is used for carrying out frequency modulation on fluctuation current generated by clean energy such as wind energy and solar energy, and stable current is output to drive a water pump to pump water to compress air; compressed air is stored through an air storage tank in the compression heat storage and air storage system, waste heat of circulating water is recycled through a water storage tank, and heat transfer between the air storage tank and the water storage tank is regulated and controlled through a heat switch formed by a light sensation material pattern layer and a light strip. The power generation system utilizes exhaust of compressed air to push a water turbine to generate power, heat storage capacity of a water storage tank is transmitted to the compressed air, and pressure intensity and temperature losses during exhaust of an air storage tank are made up. And the comprehensive control system is used for remotely monitoring and regulating the steady flow pumping system, the compression heat and gas storage system and the water pushing power generation system.

The invention belongs to the technical field of contaminated soil remediation, and particularly relates to a passivator for repairing agricultural soil polluted by heavy metal chromium, wherein the passivator comprises the following components in parts by weight: 1-10 parts of calcium polysulfide, 1-5 parts of potassium sulfide, 1-5 parts of dipotassium phosphate, 1-3 parts of sodium lignin sulfonate, 2-4 parts of potassium humate, 1-5 parts of attapulgite and 1-3 parts of quick lime. The chemical modified passivator and the modified natural passivator are compounded into the multi-element efficient chromium passivator, so that the multi-element efficient chromium passivator is suitable for chromium compound stabilization, heavy metal chromium polluted land is repaired into fertile farmland, and the multi-element efficient chromium passivator has high practical value and wide application prospects.

The invention discloses a chamomile essential oil extraction and processing technology. The chamomile essential oil extraction and processing technology comprises the following steps: (1) performing impurity removal on camomile, drying until the moisture of camomile pieces does not exceed 10%, and pulverizing to 40 meshes for later use; (2) irradiating camomile granules with LED (light-emitting diode) light, wherein the specific irradiation time is 15-25 minutes, the irradiation intensity is 15-20lx, and the color temperature of light irradiation is 5500-6000K; (3) adding 3 times by weight of anhydrous ethanol, and standing at 20 DEG C for 1 hour to obtain a mixed solution; (4) putting the mixed solution obtained after the treatment in the step (3) in a microwave extraction apparatus, and performing microwave treatment at microwave power of 400w for 10 minutes; and (5) performing vapor extraction, refrigerating the collected crude product in a refrigerator of 5 DEG C for 2 hours, and finally centrifuging to perform oil-water separation.

The invention discloses a tea tree essential oil extracting and processing technology. The technology comprises the following steps that 1, after impurities are removed, tea tree leaves are dried till the water content does not exceed 10%, and the dried tea tree leaves are crushed into 40-mesh tea tree granules for standby application; 2, the tea tree granules are irradiated through LED light particularly under the conditions that the illumination time is 15 min to 25 min, the illumination intensity is 15 lx to 20 lx, and the illumination color temperature is 5,500 K to 6,000 K; 3, absolute ethyl alcohol of which the weight is 3 times the weight of the tea tree granules is added, standing is conducted for 1 h at 20 DEG C, and a mixed solution is obtained; 4, the mixed solution treated through the step 3 is put into a microwave extraction apparatus, and microwave treatment is conducted for 10 min under the 400-w microwave power condition; 5, water vapor extraction is conducted, a collected crude product is refrigerated in a 5-DEG C refrigerator for 2 h, and centrifugal operation and oil-water separation are conducted.

The invention relates to the technical field of modified materials, and discloses tea tree oil microcapsules and a preparation method thereof. The preparation method comprises the steps that 2, a urea-formaldehyde resin prepolymer obtained in the step 1, lauryl sodium sulfate and water are taken to be stirred to be uniform at room temperature, and a first mixture is obtained; 3, tea tree oil is taken to be dissolved into absolute ethyl alcohol, mixed liquid is slowly added into the first mixture, stirring is conducted for 10-20 min, the system pH and a stirring process are regulated, a system is heated to 30 DEG-35 DEG C, solidification is conducted for 80-120 min, and then filtering is conducted to obtain an intermediate product, wherein the mass ratio of the urea-formaldehyde resin prepolymer to the tea tree oil to absolute ethyl alcohol is (8-15):(1-5):(3-6), and the mass of lauryl sodium sulfate accounts for 1%-4% of the total mass of the urea-formaldehyde resin prepolymer. According to the preparation method, the defects that the tea tree oil is volatile and unstable can be effectively overcome, and the prepared tea tree oil microcapsules are uniform in particle size distribution, smooth and full in particle, high in drug loading rate and good in slow-release effect.

The invention discloses a combination forecast modeling method of wind farm power by using gray correlation analysis, belonging to the technical field of wind power generation modeling. In particular, the invention is related to a weighted combination forecast method of wind power based on a least square support vector machine and an error back propagation neural network. The forecast method comprises that forecasted values of wind speed and wind direction are acquired in advance from meteorological departments while real-time output power is acquired from a wind farm data acquiring system; that the forecasted values of wind speed and wind direction and the real-time output power are inputted into a data processing module for data analyzing extraction and data normalization, and then normalized data is loaded to a database server; processed data in the database server is extracted by a combination forecast algorithm server to carry out model training and power forecast, and the wind farm sends running data to the data processing module in real time to realize rolling forecasting. The method of the invention achieves the goal of combination forecast of wind farm output in a short time. The method not only maximally utilizes advantages of two algorithms but also increases forecast efficiency by saving computing resources and shortening computing time.

The invention discloses a wireless signal propagator for ships, which includes a signal encoding circuit, a frequency selection circuit, a voltage stabilizing circuit and a power amplifier transmitting circuit. After RC filtering, it is sent to the input terminal of the frequency selection circuit. The frequency selection circuit generates resonance from the LC to select the frequency of the output signal of the signal encoding circuit. The output signal of the circuit is amplified for power. The invention has the advantages of strong anti-interference and anti-attenuation and accurate signal propagation.

The invention provides a method for preparing biogas through mixed anaerobic fermentation of cow dung and corn straw. The method comprises the steps of with the corn straw and the cow dung as raw materials, firstly pretreating the corn straw in a manner of mechanical crushing and basic hydrolysis, then mixing the pretreated corn straw with the cow dung in the mass ratio being (1.5-2) to 1, addingFe2+ according to the quantity being 1.0mg.L<-1>-1.5mg.L<-1>, adjusting the total solid content of a mixture to be 6%-10%, with anaerobic sludge as a fermentation initiator, controlling the anaerobicfermentation temperature to be 20-30 DEG C, and in the fermentation process, performing noncontinuous stirring. The biogas is prepared by the method, fermentation starting is quick, the fermentation period is shortened, the decomposition rate of raw materials is increased, the biogas yield is promoted, the content of methane in gas is increased, and the stability of the fermentation process is increased.

The invention discloses an extraction method for sage essential oil. The method comprises the following steps that 1, sage is subjected to impurity removal and then dried to obtain sage slices of which the moisture does not exceed 10%, and the sage slices are crushed to 40 meshes for use; 2, LED light is adopted for shining sage grains, wherein the shining time ranges from 15 min to 25 min, the light intensity ranges from 15 lx to 20 lx, and the light color temperature ranges from 5,500 K to 6,000 K; 3, absolute ethyl alcohol of which the weight is three times that of the sage grains is added, standing is conducted for 1 h at 20 DEG C, and a mixed solution is obtained; 4, the mixed solution subjected to treatment in the third step is arranged in a microwave extraction instrument, and microwave treatment is conducted for 10 min under the condition that the microwave power is 400 w; 5, steam extraction is conducted, a collected crude product is refrigerated for 2 h in a refrigerator of 5 DEG C, and finally centrifugation is conducted for oil-water separation.

The invention discloses a micro high-flow motor. The micro high-flow motor comprises a rack, a motor body, a pump body and a cover body, wherein the motor is arranged on the rack, and the cover body is provided with an air inlet pipe and an air outlet pipe. The pump body comprises a piston and an eccentric wheel. The eccentric wheel is connected with a rotating shaft of the motor body. The piston is connected to an eccentric shaft of the eccentric wheel in free-rotating and sleeving modes. A cavity allowing a piston piece to swing therein is formed in the rack. The motor body, the eccentric wheel and the piston are combined so that the flow can reach 15-25 L / min when the motor body operates, and the negative-pressure value can reach 76 kpa or over; the motor body drives the piston to move forward and backward and to swing simultaneously, accordingly unstable airflow at the constant speed is generated, and therefore, when air acts on a human body, the human body has the obvious shaking feeling in the process of inhaling and exhaling the air, and discomfort caused by the continuous negative pressure is relieved to a great extent.

The invention discloses a bergamot essential oil extraction method. The method includes steps: (1) decontaminating bergamots, drying until the moisture content is not higher than 10%, and grinding to 40-mesh powder for standby application; (2) adopting LED (light emitting diode) for irradiating bergamot particles, wherein illumination time is 15-25min, illumination intensity is 15-20lx, and illumination color temperature is 5500-6000K; (3) adding absolute ethyl alcohol being three times of the bergamot particles in weight, and standing for 1h at 20 DEG C to obtain a mixed solution; (4) putting the mixed solution treated at the step (3) in a microwave extractor, and performing microwave treatment for 10min under a microwave power condition of 400w; (5) extracting vapors, refrigerating collected crude products for 2h in a refrigerator at 5 DEG C, and finally centrifuging for oil-water separation.

The invention relates to a special compound premix feed for producing selenium-enriched pork and a production method of the special compound premix feed. 1 weight percent of the premix feed is added into a raw feed, the premix feed is suitable for 120-day-age growing-finishing pigs to pig in slaughter stage, the content of selenium of the produced pork is 0.25-0.29mg / kg, the requirements of the pigs on selenium can be met, and the healthy growth of the pigs is guaranteed. A used selenium source is nano-selenium or selenium yeast, the nano-selenium is nano-scale elemental selenium by taking macromolecular substances such as proteins and saccharides as dispersing agents and has the characteristics of small particle size, large superficial area, instability and the like, the selenium yeast is a high-quality organic selenium source, the nano-selenium or selenium yeast is more easily absorbed by the organism compared with other selenium sources such as sodium selenite and amino acid chelated selenium, and has the relatively high bioavailability, safety and oxidation resistance, the selenium-enriched pork belongs to functional healthy pork with a selenium supplement effect, the selenium contained in the selenium-enriched pork is the organic selenium which is easily absorbed and utilized by the human body, and the selenium-enriched pork is an excellent selenium supplement food.

The invention discloses an energy storage device capable of factory production for energy storage and power generation. The energy storage device comprises a shaft lever, a plurality of energy storage units, a gear box, a braking gear, a brake member and a motor, wherein each energy storage unit comprises an annular cover shell and an energy storage spring respectively, and the shaft lever is sleeved with the energy storage units; the energy storage units form a cylindrical energy storage main body, and an output shaft of the gear box is connected with the outer side end of the shaft lever; an input shaft of the gear box is sleeved with the braking gear, and the brake member includes a support base and a block pin; the block pin can reach the position between each two adjacent external teeth of the braking gear, and braking of the braking gear is formed; the output end of the motor is connected with the end part of the input shaft of the gear box in a transmission mode; the motor drives the shaft lever to rotate through the gear box, and the energy storage springs contract under the action of the rotation of the shaft lever so as to achieve winding for energy storage. The energy storage device adopts the basic principle of the energy storage of an old type table clock, and the basic principle is enlarged infinitely within the permissible range of the capabilities of manufacture, transportation and installation, so that the purpose of the energy storage is achieved.

The invention discloses a sage essential oil extraction method. The method comprises the following steps of: (1) removing impurities from sage, then drying the sage until the moisture does not exceed 10% of sage pieces and grinding the sage into 40-mesh grains for later use; (2) adopting LED light to irradiate the sage grains, wherein the illumination time is 15-25 minutes, the illumination intensity is 15-20lx, and the color temperature of illumination is 5500-6000K; (3) adding absolute ethyl alcohol with weight being 3 times that of the sage grains and standing at 20 DEG C for one hour, thus obtaining a mixed solution; (4) putting the mixed solution after treatment in the step (3) in a microwave extraction apparatus and carrying out microwave treatment for 10 minutes under the condition that the microwave power is 400w; and (5) then carrying out water vapor extraction, refrigerating a collected crude product in a refrigerator at 5 DEG C for two hours and finally carrying out centrifugation operation to carry out oil-water separation.

The invention provides an oil suspension additive and a preparation method and application thereof, and belongs to the technical field of pesticides, the oil suspension additive is prepared by adding nonylphenol polyoxyethylene ether NP-4, nonylphenol polyoxyethylene ether NP-6, nonylphenol polyoxyethylene ether NP-8 and an emulsifier EL-20 into a sufficient amount of solvent oil, stirring and mixing; the obtained oil suspension additive can be used for preparing oil suspension preparations such as sulfonylurea herbicides, sulfoxaflor insecticide and pyrethrin insecticide. According to the invention, different nonylphenol polyoxyethylene ether and castor oil polyoxyethylene ether have different oleophylic group types, different hydrophilic group lengths and different HLB (Hydrophile-Lipophile Balance) values, different particles cannot be aggregated by utilizing steric hindrance among the emulsifier particles through mutual matching in a specific proportion, so that good dispersibility and emulsibility are maintained, and the stability of the emulsifier is improved. Physical phenomena such as unqualified emulsion stability, sedimentation and caking and bottoming in heat storage are effectively prevented.

The invention belongs to the technical field of fertilizers, and particularly relates to a preparation method of a special fertilizer for tea tree germination. The preparation method of the special fertilizer for the tea tree germination comprises the steps of: firstly preparing a mixed slurry of biomass carbon, ammonia water and humic acid, and then introducing CO2 or a gas containing CO2, separating products, drying, and obtaining the special fertilizer for the tea tree germination. The application is different from the direct mixing of biomass carbon and ammonium hydrogen carbonate, adoptsthe biomass carbon with a surface rich in acidic functional groups as a crystal nucleus / carrier, and prepares a biomass carbon-based compound fertilizer through a physical chemical adsorption-chemicalreaction method. That is, the special fertilizer is obtained by reacting NH3+CO2+H2O on the inner and outer surfaces of pores of the biomass carbon, and organic combination with the biomass carbon and humic acid ensures the comprehensive utilization of nitrogen, and has a significant effect on the spring germination of tea trees; and the special fertilizer has high stability, achieves an effect of sustained release, overcomes the shortcomings of a traditional carbon ammonium fertilizer easy to decompose and volatilize, and effectively improves the utilization rate of the fertilizer.

The invention discloses a micro high-flow motor. The micro high-flow motor comprises a rack, a motor body, a pump body and a cover body, wherein the motor is arranged on the rack, and the cover body is provided with an air inlet pipe and an air outlet pipe. The pump body comprises a piston and an eccentric wheel. The eccentric wheel is connected with a rotating shaft of the motor body. The piston is connected to an eccentric shaft of the eccentric wheel in free-rotating and sleeving modes. A cavity allowing a piston piece to swing therein is formed in the rack. The motor body, the eccentric wheel and the piston are combined so that the flow can reach 15-25 L / min when the motor body operates, and the negative-pressure value can reach 76 kpa or over; the motor body drives the piston to move forward and backward and to swing simultaneously, accordingly unstable airflow at the constant speed is generated, and therefore, when air acts on a human body, the human body has the obvious shaking feeling in the process of inhaling and exhaling the air, and discomfort caused by the continuous negative pressure is relieved to a great extent.