278 results about "Stearate" patented technology

The invention relates to the technical field of insulating materials, in particular to insulating powder and a preparation method thereof. The invention discloses a flame-retardant coating which comprises the following components in parts by weight: 15-25 parts of epoxy resin, 10-20 parts of aluminum hydroxide, 5-12 parts of nano boron nitride, 1-3 parts of a silane coupling agent KH-560, 3-8 parts of polytetrafluoroethylene micro powder, 2-6 parts of fluorine-modified montmorillonite, 4-9 parts of melamine cyanurate, 2-5 parts of nano titanium dioxide, 1-4 parts of a fluorine-modified graphene oxide-polyaniline composite material and 0.5-2 parts of pentaerythritol stearate. The anti-corrosion coating is prepared from the following components in parts by weight: 1 to 3 parts of nano zinc oxide, 5 to 10 parts of glass fiber, 2 to 5 parts of polyhedral oligomeric silsesquioxane-polyimide copolymer, 1 to 4 parts of ferrocenyl epoxy resin and 0.5 to 2 parts of perfluorooctyltriethoxysilane. The insulation powder is high in corrosion resistance, excellent in insulation, heat dissipation and mechanical performance, environmentally friendly in processing, good in adaptability, capable of prolonging the service life of equipment and reducing the cost, suitable for special environments and wide in popularization prospect.

The invention provides a grinding fluid, the grinding fluid comprises a base fluid, a grinding material, nano-diamond and a dispersion stabilizer, the base fluid comprises polyether and silicone oil, the grinding material comprises surface modified silicon carbide particles, and the dispersion stabilizer comprises polyethylene glycol stearate and polyvinylpyrrolidone. The surface roughness of a grinding piece can be reduced, the scratch density and microcracks of the surface are reduced, damage of grinding fluid to the grinding piece is reduced or even avoided, and the service life of a cutter can be prolonged. The invention also provides a preparation method of the grinding fluid and a process method using the grinding fluid.

The application belongs to the field of separation and specifically relates to a cellulose / PVDF electrostatic spinning oil-water separation membrane and a preparation method thereof. The preparation method comprises the following steps: S1: preparing cellulose stearate; S2: mixing cellulose stearate obtained in step S1 and polyvinylidene fluoride (PVDF) prepared into solutions respectively to obtain a spinning solution; and S3: defoaming the spinning solution obtained in step S2 and then electrostatic spinning to obtain a cellulose stearate / polyvinylidene fluoride (PVDF) hydrophobic oleophilic oil-water separation membrane. The mixed electrostatic spinning nanofiber membrane has better mechanical properties, and due to the addition of modified cellulose, the nanofiber membrane has greater separation flux, higher separation efficiency and greater porosity.

The invention discloses a high-whiteness EVA chemical foaming sole material and a preparation method thereof, and belongs to the technical field of footwear products. The EVA chemical foaming sole material is formed by chemical foaming of an EVA composite raw material. The EVA composite raw materials mainly comprise 50 to 70 parts of EVA, 20 to 40 parts of an olefin thermoplastic elastomer, 0.4 to 0.7 part of a peroxide cross-linking agent, 2 to 4 parts of an AC foaming agent, 1 to 2 parts of zinc oxide, 0.3 to 0.8 part of 6-hydroxy-1, 2, 3, 4-tetrahydroquinoline, 0.5 to 1 part of nano zinc carbonate and 0.5 to 1 part of pentaerythritol tetrastearate. The whitening effect of the sole material can be realized on the premise of protecting the EVA foaming-crosslinking structure; therefore, the attractiveness of the product is improved, the durability is better, the mechanical properties and other properties of the EVA foamed sole are not influenced, and the high-quality requirements of elasticity, pressure resistance, comfort and the like of sports shoes can be met.

The invention relates to the technical field of pharmaceutical preparations, in particular to a solid dispersion-based sustained-release drug composite carrier as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out synergistic spray drying on double polymers (hydroxypropyl methylcellulose acetate succinate and polyvinylpyrrolidone-vinyl acetate copolymer) to form a solid dispersion; compounding with mesoporous silica and calcium silicate for localization, and spraying ethanol to activate pores; calcium stearate and magnesium stearate are sequentially added for lubrication; prefabricating a sustained-release skeleton master batch; and finally, mixing, rolling and forming. According to the method, through hierarchical structural design, the drug stability, the powder fluidity and the release controllability are remarkably improved, the method is suitable for industrial production of the dihydroergoline mesylate sustained release preparation, and a release curve is smooth and reliable.

The invention provides a method for controlling an oxidation reaction of an ADC (azodicarbonamide) foaming agent by intermittently introducing chlorine, which comprises the following steps: dissolving biurea and water in a reaction kettle according to a solid-to-liquid ratio of 1: (2-3) to obtain biurea slurry; adding halide into the biurea slurry as an oxidation aid, and introducing chlorine into the reaction kettle for reaction under the condition that the temperature in the reaction kettle is adjusted to 10-40 DEG C; when the reaction is carried out to 85%-90%, chlorine introduction is stopped, polyoxyethylene stearate is added into the reaction kettle to serve as a surfactant, and the mass ratio of reactants in the reaction kettle to polyoxyethylene stearate is 100: (0.01-0.1); continuously introducing chlorine into the reaction kettle, and controlling the chlorine to be intermittently introduced into the reaction kettle until the reaction is finished; the chlorine introduction time is 1-30 min / time, and the intermittent time is 1-40 min / time; filtering and cleaning reactants in the reaction kettle step by step, and drying, crushing, grading and the like after the pH value of the reactants reaches 6.5 to obtain a finished product ADC foaming agent. The end point of the ADC oxidation reaction can be effectively controlled, and excessive chlorine is prevented from decomposing the product.

The invention relates to the technical field of cosmetics, and discloses a composition and application thereof to preparation of a reagent for intervening lip aging. The composition comprises Inca inchi seed oil, stearyl glycyrrhizinate and a myrothamnus flabellifolia leaf and stem extract, wherein the mass ratio of the Inca inchi seed oil to the stearyl glycyrrhizinate to the myrothamnus flabellifolia leaf and stem extract is (1-15): 1: (0.2-10). According to the composition, through scientific compounding and a multi-target epigenetics mechanism, the function of tough lip blood vessels is improved and maintained, meanwhile, the epidermis is repaired, and lip rejuvenation is achieved through the dual effects of the epidermis and the blood vessels.

The invention belongs to the technical field of daily plastic products, and particularly relates to a high-temperature-resistant reinforced transport case material and a preparation method thereof. The transport case is prepared from the following raw materials in parts by mass: 88 to 100 parts of polypropylene, 8 to 12 parts of PP-g-ITA, 7 to 10 parts of PP-g-AN, 0.05 to 0.2 part of an aryl dicarboxamide nucleating agent, 5 to 8 parts of fibers, 3 to 5 parts of mica powder, 0.2 to 0.5 part of an antioxidant, 0.1 to 0.2 part of a benzotriazole ultraviolet absorbent, 0.2 to 0.3 part of a silane coupling agent, 0.1 to 0.2 part of polyethylene wax, 0.2 to 0.4 part of calcium stearate and 0.1 to 0.3 part of pentaerythritol stearate. The preparation method of the high-temperature-resistant reinforced transport case material is simple, and a transport case prepared from the high-temperature-resistant reinforced transport case material is excellent in thermal stability, weather resistance and mechanical property.

The application discloses a preparation method of a nickel-doped and high-hydrated cobalt-chromium-iron ore monocrystal under high temperature and high pressure, and the method comprises the following steps: preparing a cylindrical cobalt-chromium-iron ore sample by taking solid basic cobalt carbonate powder, solid chromium (III) acetate hydroxide crystal powder, solid nickel stearate, solid oxalic acid powder, solid chromium hydroxide powder, solid nickel hydroxide powder and liquid dilute nitric acid as starting raw materials; preparing water source sheets by taking chromium hydroxide powder and nickel hydroxide powder in a weight ratio of 4:1; placing two water source sheets at two ends of the cylindrical cobalt-chromium-iron ore sample respectively and then putting them into a double-capsule structure sample bin; and obtaining a cobalt-chromium-iron ore monocrystal after high-temperature and high-pressure reaction, so that the blank of the preparation technology of the nickel-doped and high-hydrated cobalt-chromium-iron ore large-grain monocrystal under the current high-temperature and high-pressure condition is solved, and the experimental sample of the nickel-doped and high-hydrated cobalt-chromium-iron ore large-grain monocrystal is obtained.

The invention belongs to the technical field of polylactic acid filter materials, and discloses an antibacterial electret polylactic acid composition for melt-blowing, a preparation method of the antibacterial electret polylactic acid composition, polylactic acid granules, application of the polylactic acid granules and polylactic acid melt-blown cloth, the antibacterial electret polylactic acid composition for melt-blowing comprises polylactic acid, a plasticizer, a composite electret and a guanidine salt polymer, optionally a dispersant and optionally an antioxidant; relative to 100 parts by weight of polylactic acid, the content of the plasticizer is 0.5-2 parts by weight, the content of the composite electret is 0.5-3 parts by weight, the content of the guanidine salt polymer is 0.3-3 parts by weight, the content of the dispersing agent is 0-0.3 part by weight, and the content of the antioxidant is 0-0.2 part by weight; the composite electret comprises tourmaline powder, a hindered amine light stabilizer, hydroxy stearate and a dendritic polymer. The composite electret and the guanidine salt polymer are added into the polylactic acid composition, so that the antibacterial polylactic acid melt-blown cloth with excellent antibacterial effect and efficient filtering efficiency is prepared.

The invention relates to the technical field of 3D printing materials, and particularly discloses nylon powder for 3D printing and a preparation method of the nylon powder. The nylon powder for 3D printing is mainly prepared from the following raw materials in percentage by weight: 95-99% of spherical nylon-based powder, 0.5-3% of a nucleating agent, 0.3-1.5% of stearate and 0.2-0.5% of fumed silica. Through mutual cooperation of the raw materials, the nylon powder for 3D printing has the advantages of high fluidity, good powder laying thickness uniformity, wide sintering window temperature and high tensile strength of a printed piece, and meets market requirements.

The present invention relates to a cosmetic preparation comprising at least one mineral sunscreen filter, polyglyceryl-4 diisostearate / polyhydroxystearate / sebacate, polyhydroxystearic acid, isostearic acid, polyglyceryl-2 oleate and polyglyceryl-2 stearate; and the use of the preparation for protection against sunlight.

The embodiment of the invention discloses a plastic filling lubricating master batch and a preparation method thereof. The plastic filling lubricating master batch comprises a filling agent, a polypropylene material, a heat stabilizer, an antioxidant, a reaction accelerator, a modifier, an elastic material, a lubricant and a coupling agent, wherein the filling agent is calcium carbonate; the polypropylene material is polypropylene 7042; the heat stabilizer is compounded by zinc stearate and a beta-diketone auxiliary stabilizer; the antioxidant comprises a main antioxidant, an auxiliary antioxidant and a synergist; the reaction accelerant is a compound of stearic acid and citric acid; the modifier is PE wax and / or EBS; the elastic material is POE (Polyolefin Elastomer); the lubricant is prepared by compounding erucyl amide and modified polyethylene wax; the coupling agent is a titanate coupling agent.

The application relates to the technical field of battery diaphragm, and discloses a lithium ion battery diaphragm with high viscosity and high safety, which is prepared from the following components in parts by weight: 15-20 parts of polyolefin, 80-85 parts of pore-forming agent and 2-4 parts of filler; the viscosity average molecular weight of the polyolefin is 1-4 million; the raw material of the filler comprises component A and component B in a mass ratio of 1:19-19:1; the component A comprises barium stearate; and the component B comprises one or more of lithium molybdate, lithium tungstate and lithium tantalate. Through the technical scheme, the problem of low strength of the lithium battery diaphragm in the related art is solved.

The invention provides a flame-retardant polyethylene master batch filled with magnesium hydroxide and a preparation method of the flame-retardant polyethylene master batch, and relates to the field of flame-retardant materials. The flame-retardant polyethylene master batch filled with magnesium hydroxide comprises the following raw materials in parts by mass: 8-20 parts of linear low-density polyethylene, 3-6 parts of an ethylene-octylene copolymer, 60-80 parts of modified magnesium hydroxide powder, 8-12 parts of montmorillonite powder, 3-5 parts of zinc borate, 2-5 parts of graphite powder, 1-4 parts of a lubricant, 4-8 parts of a coupling agent, 2-4 parts of barium stearate and 0.5-2 parts of an antioxidant. Compared with a common polyethylene material, the flame-retardant polyethylene master batch filled with magnesium hydroxide prepared by the invention has higher flame retardance, smoke suppression and carbon forming properties, also improves the dripping resistance of the polyethylene material, and can be used for preparing products such as polyethylene wires and cables, polyethylene foam boards, polyethylene pipes and the like.

The present application belongs to the technical field of pharmaceutical preparation, and provides a quick-dissolving nicorandil tablet and a preparation method thereof. The tablet is composed of an active ingredient nicorandil, hydroxypropyl methylcellulose acetate stearate, maltodextrin powder, a disintegrating agent and a lubricant. The product of the present application has good performances in moisture and heat stability and dissolution rate. In particular, the dissolution rate still has the performance of quick dissolution after accelerated investigation, which is beneficial to the emergency treatment of angina pectoris.

The application discloses a manufacturing process of a stamping processing protective film, which comprises the following steps: step one, stirring and mixing zinc oxide, polysebacic acid-decanediol diol and dicyclohexyl carbodiimide at 50-60 DEG C to obtain material A; step two, putting 100 parts of low-density polyethylene with a melt index of 0.5-5 g / 10 min, metallocene linear low-density polyethylene with a melt index of 1.8-2 g / 10 min, oleic acid amide, zinc stearate, stearate and an antioxidant into a mixer, uniformly mixing and then extruding and granulating in a double-screw extruder to obtain material B; step three, putting material A, material B and terpolymer polypropylene into a banbury mixer, discharging after banburying for 10-30 min to obtain a master batch; and step four, blow molding the master batch to obtain a polyethylene base material layer. The protective film improves the elongation at break of the film and also improves the puncture resistance of the protective film.

The utility model belongs to the technical field of tail gas treatment devices, and particularly relates to a tail gas absorption device of a stearate reaction kettle, which comprises a filter assembly for filtering gas and an adsorption assembly for adsorbing the gas, the filter assembly comprises a first shell, a first filter structure and a first material pipe, the first filtering structure is separably arranged in the first cavity and divides the first cavity into a gas cavity and a material cavity which are distributed up and down, one side of the gas cavity is connected with a first gas pipe, and the other end of the first gas pipe is communicated with the adsorption assembly. Compared with the prior art, direct contact between the discharging end of the reaction kettle and the outside atmosphere is changed into indirect contact through the filtering assembly and the adsorption assembly, tail gas leakage caused by direct tail gas suction is avoided, the tail gas absorption rate can be improved, on the one hand, solid-gas separation is conducted on products in the first cavity through the first filtering structure, and the product quality is improved. Therefore, the condition that a small amount of products are taken away during tail gas recovery is reduced.

The invention discloses snowflake cream with pearly luster and a preparation process of the snowflake cream. The snowflake cream comprises the following raw material components: a phase A: water; butanediol; glycerol; methyl glucitol polyether-20; a polyacrylate cross-linked polymer-6; sodium hyaluronate; potassium hydroxide (90%); 4-hydroxyacetophenone; xanthan gum; phase B: caprylic / capric triglyceride; cetostearyl alcohol; stearic acid; a polydimethylsiloxane; squalane; simmondsia chinensis seed oil; mineral oil; and polyethylene glycol (PEG)-100 stearate. Glyceryl stearate; tocopheryl acetate; isononyl isononanoate; a phase C: 1, 2-hexanediol; carnosine; a centella asiatica extract; collagen; the snowflake cream has the advantages of uniform pearly luster texture and the advantages of traditional snowflake cream.

The application relates to the cable technical field and discloses a 35kV aging-resistant power cable which comprises, from inside to outside, a conductor, a conductor shielding layer, an insulation layer and a sheath layer; the raw material of the sheath layer comprises the following components in parts by weight: 100 parts of chlorinated polyethylene, 15-20 parts of chlorosulfonated polyethylene material, 7-12 parts of ethylene-vinyl acetate copolymer, 10-15 parts of ethylene-propylene-diene rubber, 10-15 parts of filler, 0.2-0.4 parts of vulcanizing agent, 2-3 parts of activator and 5-8 parts of compatibilizer; the raw material of the chlorosulfonated polyethylene material comprises the following components in parts by weight: 60 parts of chlorosulfonated polyethylene, 5-10 parts of zeolite, 5-10 parts of illite and 0.5-2.5 parts of rare earth stearate. Through the technical scheme, the problem that the aging resistance of the sheath layer of the power cable needs to be improved in the related art is solved.

The invention discloses a preparation method of soft magnetic composite material powder. The preparation method comprises the following steps: (1) preparing coating liquid; (2) pretreatment: carrying out oil removal, degreasing and hydroxylation treatment on the metal magnetic material powder; (3) coating: filling the metal soft magnetic powder into a rotary evaporator and injecting coating liquid; (4) aging and drying; (5) calcining at low temperature, namely preserving heat at 150-700 DEG C for 0.1-50 hours, wherein the heat can be preserved in stages; the heat preservation atmosphere is N2 / H2 mixed gas, the hydrogen proportion is smaller than or equal to 80 vol%, and the oxygen partial pressure is smaller than or equal to 10 <-3 > Pa; and (6) powder mixing: adding a lubricant, a forming agent or a secondary coating agent into the metal soft magnetic powder coated with Al2O3. The forming agent or the secondary coating agent is silicon resin or epoxy resin, and the lubricant is stearic acid or / and stearate or wax; (7) die forming; (8) heat treatment; (9) impregnation; and 10, curing. Compared with the prior art, the preparation method is simple, good in magnetic performance, safe and environmentally friendly.

The application discloses a medical irradiation-resistant non-woven fabric and a preparation method thereof, and belongs to the technical field of non-woven fabrics. The medical irradiation-resistant non-woven fabric comprises the following raw materials in mass fractions: 100 mass parts of polypropylene resin, 1-2 mass parts of irradiation-resistant stabilizer, 1-2 mass parts of antibacterial agent, 0.4-0.6 mass parts of antistatic agent, 0.6-0.8 mass parts of antioxidant, 0.6-0.8 mass parts of lubricant, 0.1-0.2 mass parts of stearate, and the irradiation-resistant stabilizer is prepared by grafting an amino group on a carbonyl-containing aromatic hydrocarbon substrate through a carrier coated with an absorbent. The irradiation-resistant stabilizer is introduced in the preparation process of the polypropylene non-woven fabric, so that the irradiation-resistant performance of the non-woven fabric is improved, and the non-woven fabric still has certain anti-fracture performance and toughness after multiple irradiations.

The invention relates to the stearate salt of sabcomeline. The stearate salt of sabcomeline may be a solid, preferably in a crystalline solid. The invention also relates to various polymorphic forms of sabcomeline stearate salt. The invention further relates to methods of preparing the stearate salt of sabcomeline and its various polymorphic forms and to pharmaceutical compositions containing the stearate salt of sabcomeline and its various polymorphic forms.

The invention discloses oxidized paraffin and antirust wax and a preparation method thereof, and relates to the field of paraffin. The antirust wax comprises oxidized paraffin, an emulsifier, an antirust agent and water, and the emulsifier is at least one of sorbitan monooleate, lauryl sodium sulfate and fatty alcohol-polyoxyethylene ether; the antirust agent is at least one of cyclohexylamine stearate, alkenyl succinic acid and alpha-mercaptobenzothiazole; the oxidized paraffin is loaded with a Mn metal element through a carrier. The catalyst loaded with the active component Mn is added in the preparation process of the oxidized paraffin, the acid value and the soap value of the oxidized paraffin are effectively increased, the oxidized paraffin interacts with the specific emulsifier and the antirust agent, the emulsifier does not affect the anti-oxidation protection function of functional components, and meanwhile, the antirust agent and the oxidized paraffin cooperate with each other to achieve the anti-corrosion effect in a synergistic mode; and the antirust capability of metal in a humid and hot environment and an acid-base environment is improved, and the application prospect is expanded.

The invention belongs to the technical field of polylactic acid filter materials, and discloses a composite electret, a polylactic acid composition, a preparation method of the composite electret, polylactic acid granules, application of the polylactic acid granules and polylactic acid melt-blown cloth, and the composite electret comprises tourmaline powder, a hindered amine light stabilizer, hydroxy stearate and a dendritic polymer. The composite electret provided by the invention is a novel organic-inorganic composite electret, and can solve the problems that the addition amount of common inorganic electrets is large, so that polylactic acid melt-blown fibers are too thick, the yarn breaking rate is high, and the filtering efficiency is low.

The application relates to the field of marine cement materials, and particularly discloses a preparation method of a solid-waste-based early-strength marine cement-based material, which comprises the following steps: (1) uniformly mixing calcined recycled concrete micro powder and magnesium oxide whiskers, then mixing the mixture with water to form wet materials, and then standing; after hardening, crushing and grinding the obtained solidified body to obtain modified recycled micro powder; (2) uniformly mixing the modified recycled micro powder with a hot isopropyl alcohol solution of a stearate to obtain a waterproof agent after drying; (3) uniformly mixing magnesium oxide whiskers with a hot isopropyl alcohol solution of magnesium stearate to obtain modified magnesium oxide whiskers after drying; (4) uniformly mixing potassium dihydrogen phosphate, the waterproof agent and the modified magnesium oxide whiskers to obtain an early-strength agent; and (5) uniformly mixing granulated blast furnace slag powder, fly ash, solid-waste-based gypsum powder, carbide slag powder, coarse aggregate, fine aggregate, a water reducing agent, the early-strength agent and mixing water to obtain the solid-waste-based early-strength marine cement-based material. The early-strength additive can not only improve the early strength of the solid-waste-based cement-based material, but also improve the adaptability to the marine environment.

The application discloses an anti-permeation low-shrinkage inorganic coating and a preparation method thereof. The anti-permeation low-shrinkage inorganic coating comprises cement material 40-60 parts by mass, active mixed material 15-30 parts by mass, gypsum 5-15 parts by mass, talcum powder 5-15 parts by mass, glycerin stearate 0-2 parts by mass and additive 4.7-6.7 parts by mass. The application selects green inorganic material, combines the characteristics of slow hydration of low-heat Portland cement, micro-expansion of high-magnesium low-heat Portland cement and micro-expansion of ettringite-like product formed between gypsum and cement hydration product, uses micro-expansion to relieve the shrinkage problem of the material, makes the material form a dense structure, and makes the material have the hydrophobic anti-permeation characteristics through the saponification reaction of glycerin stearate under alkaline conditions.

The invention relates to the technical field of wood-plastic composite materials, and particularly discloses a special composite lubricant for PE and PP wood-plastic and a preparation method thereof, the special composite lubricant comprises the following components: EVA solid waste oligomer, polyethylene wax, pentaerythritol stearate, inorganic filler, alkyl quaternary ammonium salt and short-chain fatty acid ester; a residual coordination catalyst in an EVA solid waste oligomer is activated by alkyl quaternary ammonium salt under a heating condition, in-situ polymerization / grafting reaction is carried out through catalysis, nitrogen-containing polar chain segments are directionally introduced, hydroxyl sites are introduced through chain transfer reaction, and the like, so that the dispersity of the fiber is improved, and the interface adhesion is enhanced; by adding the modified polyethylene wax, the short-chain fatty acid ester and the pentaerythritol stearate, friction in a melt can be synergistically adjusted, interface layering can be reduced, the modified polyethylene wax can improve the dispersing performance of the wood flour, and the flame retardance of the wood flour can be improved. The prepared composite lubricant can be compatible with wood flour and PE resin, and is high in stability.

The application discloses a kind of high-performance high fluidity magnetic particles for injection molding and a preparation method thereof, and relates to the technical field of bonded magnetic composite materials.The preparation steps include the following:S1. Anisotropic samarium iron-nitrogen magnetic powder is mixed with isotropic samarium iron-nitrogen magnetic powder to obtain a mixed magnetic powder;S2. Under stirring conditions, ethanol, ethylenediaminetetraacetic acid, phosphate ester coupling agent and antioxidant are added to the mixed magnetic powder, which is stirred and dispersed uniformly, and then dried to obtain pretreated magnetic powder;S3. The mixed material composed of pretreated magnetic powder, silane coupling agent, nylon, diacetyl epoxy vegetable oil glyceride, oleic acid amide and cerium stearate is added to an extrusion granulator, and the magnetic particles for injection molding are obtained by extrusion granulation under nitrogen conditions.The magnetic particles for injection molding prepared by the method have high fluidity, can meet the demand for injection molding of complex shapes, have stable mechanical properties, and have oxidation resistance, which ensures long-term stable magnetic properties of the magnetic particles and reduces magnetic attenuation during use.