2453 results about "Magnetic stirrer" patented technology

The invention provides a simple method, devices and several machines for simultaneously stirring and aerating thousands of vessels or wells of microplates in a robust manner and with economy. This method uses the simple principle of magnetic stirrers being levitated vertically when passed laterally or vertically through a strong horizontal dipole magnetic field. The dipole magnetic fields may be produced by using permanent magnets, electromagnets or a modulating / reversing electro-magnetic field. Each vessel contains a magnetic ball, disc, bar, dowel or other shape (stirrers) which in their magnetic attraction to the dipole magnetic field will cause the stirrers to levitate up in the vessel as the stirrer's magnetic poles attempt to align with the center of the dipole's magnetic field. The stirrers will fall to the bottom of the vessel by gravity or by changing the relative position of the levitating magnetic field to pull them down, or by passing the vessel laterally over another magnetic field. The up and down movement of the stirrers provides a vigorous mixing of the contents of many vessels at same time. If the level of the vessel's meniscus is situated so the stirrers pass through it on their way up and down, the air / liquid interface is significantly increased thereby significantly increasing aeration of the liquid.

The invention provides a simple method, device and several machines for simultaneously stirring thousands of vessels or wells of microplates in a robust manner and with economy. This method uses the simple principle of magnetic stirrers aligning themselves to a vertical driving magnetic field placed beneath them and moving laterally or by moving the vessels over a stationary magnetic field or by spinning the drive magnets, or by using a modulating / reversing electromagnetic field to produce the moving effect. Each vessel contains a magnetic disc, bar, dowel or other shape (stirrers) which in it's magnetic attraction to the vertical driving magnetic field will cause it to move and align it's magnetic field as the opposite poles of the drive magnet and the stirrer attract each other. The attraction of the stirrers to the vertical driving magnetic field causes the stirrers to stand on end and tumble as the stir devices try to align to the opposite moving magnetic pole. The stirrers tumble because the walls of the vessels or friction with the vessel bottom prevents their lateral movement.

The invention relates to a nanoparticle-added composite foam system used for an oil and gas field and a preparation method thereof. The composite foam system comprises components of, by mass, 0.3 to 0.5 parts of an anionic surfactant, 1 to 1.5 parts of modified silica nanoparticles, 0.03 to 2.3 parts of counter-ion salt, and 100 parts of water. The method comprises mixing the abovementioned components according to ratio, stirring by using a magnetic stirrer, standing, and then rapidly stirring to form well stable foam using a Waring Blender way. According to the composite foam system, the produced foam has a longer half life than that of foam stabilized by ordinary surfactant, and a larger start-foaming volume than that generated by adding a foam stabilizer The system has advantages of simple formula and preparation technology and good salt tolerance and temperature tolerance, can adapt to complex oil reservoir condition underground, does not pollute stratum, is capable of effectively blocking large channels and improving sweeping efficiency, and thus has good application prospects in oil field exploitation, especially in foam displacement.

The invention discloses a method for preparing antibacterial nanometer silver colloid, belonging to the technical field of nanometer biological materials. The method uses a chemical reduction method, comprising the following steps: dissolving water-soluble protective agent in silver nitrate water solution with the concentration of 0.001-0.1mol / L, wherein the mass ratio of protective agent to silver nitrate is 0.5-10.0:1; carrying out ice bath on sodium borohydride water solution with the concentration of 0.001-0.2mol / L for 10-30min; and dropwise adding the silver nitrate water solution containing protective agent in the sodium borohydride water solution with the speed of 30-60 drop / min, stirring by a magnetic stirrer, stirring for 20-40min after dropwise adding to prepare the nanometer silver colloid with the grain size of 5-80nm, wherein the mol ratio of the sodium borohydride to the silver nitrate is 1.0-30.0:1. The nanometer silver colloid prepared by the invention has the advantages of high concentration, high stability, high dispensability, and obviously-enhanced antibacterial property.

The invention relates to a method of synthesizing nickel cobalt oxide electrode material using a hydrothermal method and an application thereof. The method comprises dissolving CoCl2.6H2O, NiCl2.6H2O and CO(NH2)2 into an appropriate amount of deionized water, wherein the mole ratio of CoCl2.6H2O to NiCl2.6H2O is 1 : 2; uniformly stirring the mixed solution by using a magnetic stirrer, transferring the solution into an autoclave, heating the solution to 100 DEG C and keeping the temperature constant for 10 hours; cooling the solution to room temperature, filtering, washing and drying reactants, and then annealing the reactants for 2 hours in an air atmosphere of 250 DEG C. The method is simple to operate and environmental-friendly. The prepared nickel cobalt oxide nanowire is a spinel-type cubic phase and porous, has high purity and relatively high specific surface area, and can be used as electrode materials for super capacitors, with specific capacitance thereof being 722 F / g.

Disclosed are a preparation method and application of heterogeneous Fenton-like catalyst. The preparation method includes the steps of firstly, dissolving complexing agent and metal salt in distilled water to respectively prepare complexing agent and metal salt solutions; secondly dropwise adding the metal salt solution into the complexing agent solution under the action of a magnetic mixer, and mixing for 20-60 after dropwise addition to obtain metal complex solution; and thirdly, impregnating activated carbon fiber in the metal complex solution for 1-24h, and subjecting taken-out activated carbon fiber to distilled water washing and drying to obtain the heterogeneous Fenton-like catalyst. The preparation method is simple, and conditions are mild. Environment-friendly hydrogen peroxide is used as oxidant, no extra ultraviolet light or even visible light is needed, and the heterogeneous Fenton-like catalyst is capable of efficiently degrading organic pollutants such as dye within a wide pH range of 2-10. The heterogeneous Fenton-like catalyst is well repeatable, and secondary pollution of the homogeneous Fenton reagent caused by iron ions is avoided.

A magnetically driven agitator for a mixture contained in a recipient which agitator is supported by a collar hermetically mounted in a wall of the recipient and which collar is provided with a blind sleeve inside which is housed a drive shaft provided with a first magnetic coupling. A propelling screw is disposed around the blind sleeve and is provided with a second magnetic coupling adapted to cooperative with the first magnetic coupling for driving the propelling screw about an axis of rotation. A third magnetic element carried by the propelling screw is disposed opposite a cell for detecting the movement of the third coupling element during rotation of the propelling screw about the axis of rotation.

Intelligent cooking apparatuses incorporate wireless communication technology to carryout cooking procedures. More specifically, stoves, ovens, and cookware may send and receive data wirelessly to carryout cooking procedures. An application may guide persons through recipes and automate many of the cooking procedures. Cookware may send batch information to an application for processing, display, and analysis. Cookware may use hardware for automated cooking actions, such as a magnetic stirrer and driver for stirring the contents in cookware, all monitored by various sensors located in the cookware.

The invention provides a preparation method of fibrous membrane with a super hydrophobic multi-stage nanometer structure, which is characterized by comprising the following specific steps: 1, at room temperature, adding hydrophobic polymer and hydrophobic inorganic nanoparticles into a sealed container filled with solvent, putting the sealed container on a magnetic stirrer to stir at the revolving speed of 10-200 rpm, and obtaining solution with even property; 2, at room temperature, inputting solution obtained in step 1 onto a spinning nozzle at constant flow velocity; connecting the spinning nozzle to a high voltage static generator to carry out electrostatic spinning; and receiving spun fiber by a receiver to obtain the fibrous membrane with super hydrophobic multi-stage nanometer structure. The invention can drastically improve the hydrophobic performance of the fibrous membrane.

A synthetic method of a novel visible light photocatalyst Bi2MoO6 (bismuth molybdate) is provided. The method includes the following steps: weighing Bi(NO3)3*5H2O and (NH4)6Mo7O24*4H2O solids at the theoretical ratio by mass of 14:1, dispersing the weighed solids into an appropriate amount of deionized water, stirring to obtain white curdy precipitates, placing the precipitates in a magnetic stirrer and stirring at normal temperature for 30 minutes, subjecting to ultrasonic treatment with a ultrasonic generator for 30 minutes to allow intensively mixing, allowing reactions of the treated white precipitates at 150-200 DEG C under sealed conditions, filtering the reaction product to collect flavescent precipitates, washing, drying, and grinding to obtain Bi2MoO6 (bismuth molybdate) photocatalyst. The photocatalyst has good photodegradation effect on target pollutants; and when the temperature of hydrothermal synthesis is 160 DEG C, the removal rate of target pollutant 4BS after photodegradation for 90 minutes reaches 99.5%. The inventive synthetic method has the advantages of simple process and low requirement for equipment, and is suitable for the synthesis of highly-active visible light photocatalyst Bi2MoO6 (bismuth molybdate).

The invention discloses a low temperature hydrothermal preparation method of alkali catalysis or Lewis acid / proton acid catalysis biomass. The method is as below: adding a certain amount of biomass, deionized water and a proper amount of alkali or Lewis acid / protonic acid into carbide carbon of biomass to a teflon inner liner, stirring to dissolve soluble biomass, filling into a stainless steel reaction kettle, and placing in an oven and reacting for a while at preset temperature, and reacting insoluble biomass in a device equipped with a heating sleeve and a thermostat magnetic stirrer under the preset temperature, wherein the reaction conditions are as below: temperature of 110-160 DEG C (preferably 120-140 DEG C) and reaction time of 6-72 h (preferably 12-36 h); naturally cooling to room temperature, conducting high speed centrifugal separation, and re-dispersing and repeatedly washing the obtained solid with deionized water and 95% ethanol to obtain a colorless supernatant, and drying to obtain carbon microsphere / nanosphere. The method provided by the invention has the advantages of low hydrothermal carbonation temperature and high carbon production rate of the biomass, and is applicable to large-scale industrial production; and the product can be used as a catalyst carrier or adsorbent.

Intelligent cooking apparatuses incorporate wireless communication technology to carryout cooking procedures. More specifically, stoves, ovens, and cookware may send and receive data wirelessly to carryout cooking procedures. An application may guide persons through recipes and automate many of the cooking procedures. Cookware may send batch information to an application for processing, display, and analysis. Cookware may use hardware for automated cooking actions, such as a magnetic stirrer and driver for stirring the contents in cookware, all monitored by various sensors located in the cookware.

The invention belongs to bioenergy source utilizing field, especially relating to a bioreactor-direct microbial fuel cell and its use. And it mainly comprises tubular anode chamber and cathode chamber and proton exchange membrane to isolate the two chambers, where both the electrodes are of unpolished high-purity graphite rod; the anode is inoculated with bacteria, where before inoculation, charging aseptic N2-CO2(80:20) mixed gas to remove all oxygen gas from culture medium and after inoculation, slowly charging mixed gas and keeping strict anaerobic environment; the cathode keeps charging aseptic air and keeps dissolved oxygen concentration in the aseptic air; in the two chambers, slowly blending with magnetic blender; before used, the battery device is processed by high pressure moisture-heat sterilization. And the invention can use glucose, fructose, xylose, sucrose, maltose, and other sugar-containing matters and organic waste water as raw materials and directly converts their chemical energies into electric energy, having characters of no medium toxicity, good stability, moderate operating conditions, clean power generation, etc.

The invention discloses a method and a device for removing organic matters from water by using double-pool double-effect visible light in response to a photo-electro-Fenton reaction. The device comprises a cathode pool, an anode pool, a saturated potassium chloride (KCl) salt bridge, a visible light response semiconductor membrane material anode, a carbon-iron composite material oxygen negative electrode, an air pump, a magnetic stirrer, a direct current stabilized voltage power supply and a visible light source, wherein an anode performs photoelectrocatalysis under the actions of visible light and anode bias voltage to remove organic pollutants from water; the carbon-iron composite material oxygen negative electrode performs cathode potential reduction on O2 under the conditions of external voltage and introduced air to produce hydrogen peroxide which is subjected to an electric Fenton reaction to generate active substances such as hydroxyl radicals and the like capable of effectively removing the organic matters from the water; electrons produced by a photoanode migrate towards an oxygen cathode under the action of anode bias voltage; the O2 is reduced by the electrons on the cathode to generate more H2O2; and the H2O2 produced on the cathode cannot migrate to the anode pool for consumption, so that higher H2O2 concentration is ensured, and the oxidation reaction of the organic matters by electric Fenton is ensured. The method and the device are suitable for treating various types of organic waste water.

The invention discloses a manufacturing method of octal-olefin succinic starch ester, which comprises the following steps: 1) blending potato starch and water in the thermostatic magnetic stirrer into emulsion; 2) adopting 3% sodium hydroxide to adjust the pH value of emulsion to 7.5-8.0; 3) adopting anhydrous alcohol to dilute octal-olefin succinic anhydride; 4) blending the diluted octal-olefin succinic anhydride and emulsion phase in the step 2) to form reacting system; adding 3% NaOH solution to maintain the pH value of reacting system; reacting 2-4h; 5) using 2mol / L alcaine to adjust the pH value to 6.4-6.6; washing through water and 70% alcohol separately; drying; grinding.

The invention belongs to the technical field of non-ferrous metal analysis and particularly relates to an electropolishing preparation method of a sample for EBSD (Electron Back-Scattered Diffraction) analysis of a titanium-aluminum alloy. The electropolishing preparation method comprises the following steps: firstly, carrying out earlier stage treatment on the sample: determining the size of the sample to be smaller than 7mm*6mm*4mm, and carrying out standard metallographic treatment and mechanical polishing on the testing surface; secondly, setting up a portable device: connecting the sample with a positive pole of a power supply, connecting a stainless steel plate with a negative pole of the power supply and matching the bottom end of electrolyte with a magnetic stirrer; thirdly, preparing the electrolyte: selecting 4 to 12 percent of perchloric acid, 55 to 65 percent of methyl alcohol and the balance of n-butyl alcohol according to the volume ratio, wherein the total amount of the electrolyte is 700ml; putting the electrolyte into a beaker with the volume of 1L; fourthly, carrying out electrolysis treatment, washing and drying: controlling the temperature to be 30 DEG C below zero to 20 DEG C below zero, controlling the voltage to be 25 to 35V and controlling the polishing time to be 40 to 55 seconds. The electropolishing preparation method disclosed by the invention has the advantages of large surface area for treating the sample and suitability for preparing titanium-aluminum alloy samples with various components and various test purposes, which are prepared by different processing method. In addition, the electropolishing preparation method has the advantages of easiness and flexibility in operation, no restriction from site facilities and the like, good polishing effect and high rate of finished products; the device has the characteristics of high mobility, low cost, easiness in promotion and wide application prospect.

The invention discloses a device and method for recovering nitrogen and phosphor in the wastewater by the ammoniomagnesium phosphate crystal method. The invention adopts an MAP nitrogen and phosphor recovery device which has a two-stage agitation of a magnetic stirring apparatus and a deposit catcher, then the wastewater of 3 / 5 to 4 / 5 of the volume of the device is added as the reactant liquor, then add magnesium source and phosphorus source regulation reaction liquor with the ration of NH4<+>: PO4<3->: Mg<2+> equal to 1:1:1 to 1:1.2:1.2, then alkali liquor is dropped continuously to maintain the PH value of the reaction liquor at 9.0 plus / minus 0.1, the magnetic stirring apparatus rotates at the speed of 400-600 r / m and the deposit catcher is driven by a motor stirrer and agitates continuously at the speed of 40-60 r / m, and finally the MAP can be obtained. The invention overcomes the problem that the activity of the crystal-forming ions drops when the PH value decreases during the crystallization process, promotes the MAP crystallization process and improves the MAP recovery rate; the magnetic stirring apparatus and the deposit catcher adopted in the MAP recovery device reduces the stirring dead area in the reactor, the reaction liquor is stirred more sufficiently, which is favorable for the MAP crystal-forming ions to form crystal; the deposit catcher that is designed to catch MAP is favorable to improve the MAP purity in the recovered products.

The invention provides a method for preparing a nanometer hardened organic silicon coating. The method is mainly characterized by comprising the following steps of: mixing ethyl orthosilicate, deionized water and various silane coupling agents (such as KH560, methyl triethoxysilane and the like) according to a proportion; adding absolute ethyl alcohol, stirring by using a magnetic stirrer, and adding an inorganic acid catalyst during the stirring; and heating and condensing the solution to obtain organic silicon composite coating solution. The solution can be used for coatings on the surface of substrates such as glass, metal, plastic and the like, and a coating is obtained by a pulling process. The obtained coating has high hardness, wear resistance and weather resistance and can be used for protecting the surface of various substrates. The method has the characteristics that: the preparation process is simple; and feasible and mass production can be realized.

The invention relates to a molybdate doped polypyrrole / epoxy resin self-healing coating, a preparation method thereof and an application thereof, and belongs to the field of metal anti-corrosion coatings. The coating is composed of two parts, namely a polypyrrole / epoxy resin system mother liquor, and a polyamide curing agent. The polypyrrole / epoxy resin system mother liquor comprises molybdate doped polypyrrole, epoxy resin, an anti-settling agent, an anti-foaming agent, a levelling agent and an organic solvent. The molybdate doped polypyrrole is added in the organic solvent and then the mixture is uniformly dispersed in an ultrasonic dispersion instrument. After that, the anti-settling agent, the antifoaming agent and the levelling agent are added respectively, and are stirred on a magnetic stirring apparatus. Then the epoxy resin is added to form the uniformly dispersed polypyrrole / epoxy resin system mother liquor. The polyamide curing agent is added in the prepared mother liquor, and is stirred to be uniformly dispersed. In this way, a molybdate doped polypyrrole / epoxy resin self-healing coating can be obtained. The coating is sprayed or brushed onto the 2024 type aluminum alloy after being subjected to oil-removing treatment. After the drying and curing process of the coating at the room temperature, a molybdate doped polypyrrole / epoxy resin self-healing coating can be formed.

This invention discloses process and apparatus for micro electroforming by using supercritical fluid. The process comprises: (1) generating supercritical fluid electroforming solution in the reactor of a fine deposition unit; (2) controlling the power source by a control unit, selecting appropriate electric parameters, and depositing metal ions onto the photoresist patterns of the cathode of the fine deposition unit; (3) removing residual photoresist to obtain fine component. The apparatus comprises a CO2 steel bottle, a high-pressure pump, a DC power source, a control unit, a fine deposition unit, a magnetic stirrer, a thermostatic bath, a backpressure valve and a recovery device. The method and apparatus in this invention can deposit compact, smooth and clear fine component, and the waste supercritical fluid electroforming solution can be recovered and recycled.

The invention relates to an obstruction testing method for soil permeability under constant flow velocity. An apparatus for obstruction testing of soil permeability under constant flow velocity is arranged and comprises a cylindrical permeation column, differential pressure sensors, a constant flow pump, a magnetic stirrer, a laser particle analyzer, an inflow water reservoir vessel, valves, pressure-resistant flexible pipes, an effluent water collection container, etc. Obstruction particles are added into the inflow water reservoir vessel and uniformly stirred by using the magnetic stirrer, so an obstruction sample is allowed to be suspended in an infiltration liquid; the constant flow pump is used for maintaining constant seepage flow and continuously supplying water; and the differential pressure sensors are used for replacing traditional piezometric tube in measurement of seepage pressure at a plurality of different seepage sections and automatically and continuously acquiring testing data. The method visually reflects rules that how the particle sizes and quantity of the obstruction particles and seepage time change seepage pressure and permeability of the sample, can change the particle size of the obstruction sample and the content of the obstruction sample in the infiltration liquid, and is capable of carrying out continuous obstruction testing of permeability under different flow velocities so as to research influence of particle migration on the permeability of soil.

The invention discloses a preparation method of flower-shaped molybdenum disulfide microspheres. The preparation method comprises the steps of dissolving ammonium molybdate tetrahydrate in deionized water to prepare a solution of 0.02-0.05 mol / L; adding thiourea to the solution, and stirring the mixture for 20-30 min by using a magnetic stirrer so that the solution is mixed uniformly, wherein the mol ratio of ammonium molybdate tetrahydrate to thiourea is (1 : 20) to (1 : 30); transferring the solution to a hydrothermal reaction kettle, performing hydrothermal reaction for 4-8 hours at 220-240 DEG, naturally cooling, centrifuging, washing by deionized water and ethyl alcohol, and drying again to obtain molybdenum disulfide microspheres. The preparation method of the flower-shaped molybdenum disulfide microspheres has the advantages that the cost is low, the process is simple and is easy to control, the appearances of the prepared microspheres are even, and the product output is high; the preparation method is applied to large-scale industrial production.

The invention provides a preparation method of an electrolyte used for a lithium manganate power battery at a high temperature, and relates to the technical field of lithium manganate power batteries. The components in the formula of the electrolyte comprise a non-aqueous organic solvent, a lithium salt, a high temperature additive, 0.1-5% by mass of a film forming additive, 0.1-10% by mass of a fire retardation additive, 0.1-10% by mass of an overcharge-preventing additive and 0.001-1% by mass of a stabilizer. The preparation method comprises: at a room temperature, weighing a film forming additive, a non-aqueous organic solvent, a high temperature additive, an overcharge-preventing additive, a fire retardation additive, a stabilizer and a lithium salt in a glove box filled with argon, pouring the raw materials into a beaker, placing on a magnetic stirrer, controlling the stirring rate until completely dissolving the lithium salt, and uniformly mixing various solvents so as to obtain the non-aqueous electrolyte, wherein the non-aqueous electrolyte has excellent high temperature cycle performance and excellent safety.

A multi-way reaction device for rapid appraisement of photo-catalysis hydrogen production activity is composed of a light source system, a reaction system, a stirring system, a sealing system, a cooling system, a sampling system and a detection system. The multi-way reaction device includes a light reactor, a tubular light source which is driven by a decelerating motor to rotate at an uniform speed is arranged in the center of the light reactor, the light source is arranged in a quartz jacket, and cooling water or a sodium nitrite solution is introduced into the quartz jacket for cooling the light source; a plurality of quartz reaction tubes are uniformly distributed around the light source, the opening part of each quartz reaction tube is in closed connection with the light reactor, a magnetic stirrer is arranged at the lower part for driving rotary at the uniform speed, all volumes of the quartz reaction tubes are the same, and the quartz reaction tubes are connected with a gas chromatography through arranging vacuum pumps and sampling pipelines. The multi-way reaction device can carry out a plurality of groups of photo-catalysis hydrogen production reactions at the same time, and rapidly screen different photolysis hydrogen production catalysts; in addition, when different detectors are selected, the multi-way reaction device can perform rapid multi-way appraisement of various photo-catalytic reactions.

A magnetically actuated mixing straw for mixing a beverage comprises magnetic protrusions located at boom end of the straw. A beverage container containing the mixing straw is placed on top of a magnetic stirrer that causes the mixing straw to rotate and mix the beverage container contents.

The invention discloses a wastewater treatment device and method for in-situ electric generation of H2O2 cooperating with O3 oxidation. The device comprises a reaction container, wherein a magnetic stirrer is arranged at the bottom of the reaction container; a stirring magneton is arranged in the reaction container; a stainless steel microporous aeration head, an inert anode and a gas dispersing cathode are arranged in the reaction container; the inert anode and the gas dispersing cathode are vertically opposite to each other; the reaction container is also provided with a pipeline for introducing O3; and the inert anode and the gas dispersing cathode adopt a DC (direct current) power supply. The method comprises the following steps of: firstly inserting the inert anode and the gas dispersing cathode into the treated wastewater solution, and connecting with the DC power supply; then connecting pure oxygen with an ozone generator by a polytetrafluoroethylene tube; connecting the stainless steel microporous aeration head at a gas outlet of the ozone generator, and inserting into the bottom of the wastewater solution; and finally, switching on the DC power supply to treat the wastewater solution. Through the invention, H2O2 is continuously and efficiently generated and can quickly react with O3 to generate.OH so as to efficiently remove persistent organic pollutants in the water body.

The invention relates to a preparation method of catalyst slurry for a membrane electrode of a fuel cell. The method comprises the following steps of (1) sequentially adding catalyst particles, water, a high polymer proton conductor solution, a Teflon solution, alcohol and a thickener for mixing; and (2) firstly stirring a mixture by using a magnetic stirrer, further stirring the mixture by using a shearing emulsifier or a homogenizer, finally carrying out oscillation by using an ultrasonic wave and obtaining the catalyst slurry. According to the preparation method, agglomeration of catalyst particles is effectively reduced and the dispersing performance of a catalyst is improved through controlling the material composition and the charging sequence and adjusting the stirring and dispersing mode. The electrochemical properties of the membrane electrode prepared by using the catalyst slurry are significantly improved; and furthermore, the process steps are simple, the operation is convenient and feasible, the raw materials are cheap and available, the energy consumption is low and the threshold is low.

A magnetic coupling assembly for a magnetic stirrer includes a non-magnetic disc embedded with two or more pairs of magnets. The two magnets of each pair are oriented with opposite magnetic poles pointing in the upward direction. When the magnetic coupling assembly is driven to rotate, it can bind one or more axially magnetized stir bar in a mixer at a relatively higher speed to achieve better mixing result without causing spin-out or jumping-flea phenomena, compared to when only one pair of magnets is used.