124results about How to "Simple manufacturing method" patented technology

The invention belongs to the field of biochar adsorbing materials, and relates to a method for preparing modified biochar with aquatic plant waste and hematite. The method includes the following steps: (1) naturally drying aquatic plants prior to crushing to obtain aquatic plant powder; (2) crushing the hematite to obtain hematite powder; (3) weighing the hematite powder prior to putting the hematite powder into deionized water, and performing ultrasonic treatment to obtain suspension; (4) weighing the aquatic plant powder, soaking the aquatic plant powder in the suspension, and stirring and drying to obtain fully mixed aquatic plant and hematite mixture; (5) weighing the fully mixed aquatic plant and hematite mixture, putting the mixture in a batch-type atmosphere furnace, and feeding nitrogen into the furnace; performing temperature programming to the target temperature, and maintaining final-temperature pyrolysis; after the pyrolysis process is finished, obtaining the target product, namely the modified biochar. The modified biochar has strong adsorbability in nitrate and phosphate, high in stability and reusable.

This invention provides an aluminum foil anode material for lithium-ion batteries and its preparation method. The method applies metallic aluminum to a monolithic material system. Based on a chemical displacement reaction, a rolling-heat treatment method is used to dope the target metal element into the aluminum foil composite material, achieving alloy composition design of the aluminum foil. Furthermore, carbon elements can be incorporated into the interlayer of the aluminum foil to improve the lithium storage performance of the aluminum foil anode. The preparation method of this invention is simple and feasible, with a simple process flow and low cost. It can modify a large quantity of aluminum foil in a short time, and the reaction raw materials can react completely, with useless reaction products volatilizing spontaneously. In addition, the modified aluminum foil material can be directly used as a lithium-ion battery anode material, effectively improving the lithium storage performance of the aluminum foil anode material.

The application provides a packaging film with positioning holographic effect and a preparation method and application thereof. The packaging film comprises a base film, a laser holographic layer, a graphic layer and a reflection layer which are arranged in a stack; the preparation method comprises the following steps: coating laser mold pressing information paint on one side of the base film, drying, using a mold pressing and printing all-in-one machine to press and print the graphic coating on the side of the laser holographic layer away from the base film after laser holographic pressing, forming the laser holographic layer and the graphic layer on one side of the base film; then preparing the reflection layer on the side of the graphic layer away from the base film to obtain the packaging film with positioning holographic effect. In the application, the structure of the packaging film is designed, and the mold pressing and printing all-in-one machine is used, so that the packaging film with accurate positioning information is prepared, the positioning deviation of the graphic and holographic positioning mark is less than or equal to 0.20 mm, the preparation method is simplified, and the production efficiency is improved.

This invention relates to the application of electromagnetic shielding composite materials, specifically to an electromagnetic shielding composite film with a gradient structure and its preparation method. Using a polymer film as the core layer, electromagnetic functional layers are sequentially deposited on both sides of the polymer core layer, and a carbon fiber felt is composited on at least one side, resulting in an electromagnetic shielding composite film with excellent electromagnetic shielding performance. The gradient multilayer structure design of this invention utilizes the principles of impedance mismatch at different interfaces and the skin effect to effectively improve the multiple reflections of electromagnetic waves between different functional layers. Furthermore, the type of polymer core layer can be changed according to different needs; using a polymer-based high-barrier film as the core layer can yield a high-barrier electromagnetic shielding packaging film that combines high barrier properties with high electromagnetic shielding.

The application discloses a nickel-based flux-cored wire for LNG storage tanks and a preparation method and application thereof, and belongs to the technical field of welding material flux-cored wires, and solves the problem that the mechanical properties and toughness of a weld after welding of an existing welding wire used for welding 9Ni steel plates are not matched with the 9Ni steel, thereby leading to low service life of the storage tank. The nickel-based flux-cored wire comprises a core and a cladding layer cladded outside the core; the cladding layer comprises, in percentage by mass, C: 0.015%, Cr: 14.5%-20.0%, S: 0.04%, P: 0.04%, and the balance of Ni and inevitable impurities; and the core comprises, in percentage by mass, Co: 0.5%-2.5%, Cr: 13.0%-18.0%, Si: 0.15%, Al: 0.01%-0.03%, Mn: 0.001%-0.02%, Mo: 15%-17%, W: 10%-20%, Fe: 10%-15%, and the balance of Ni and inevitable impurities.

This invention discloses high-entropy rare-earth silicate ceramic nanopowders, their preparation methods, and applications. The preparation method of the high-entropy rare-earth silicate ceramic nanopowders of this invention includes the following steps: 1) dissolving rare-earth oxide powder in an acid solution to prepare a rare-earth salt solution, then adding urea and silica powder and performing a gelation reaction to obtain a gel; 2) igniting the gel for combustion synthesis, grinding, and obtaining a precursor powder; 3) calcining the precursor powder to obtain the high-entropy rare-earth silicate ceramic nanopowders. The high-entropy rare-earth silicate ceramic nanopowders of this invention possess excellent characteristics such as fine particle size, uniform elemental distribution, large component space, and absence of impurities. Furthermore, its preparation method has advantages such as fast synthesis speed, simple equipment, simple and controllable process, and low industrialization cost, making it suitable for application in hot-end components of aerospace engines and possessing very broad application prospects.

This invention proposes a sludge brick based on sewage treatment plant sludge and its preparation method, belonging to the field of building materials technology. The sludge brick, by weight, comprises the following raw material components: 50-70 parts sewage sludge, 8-12 parts reinforcing agent, 8-10 parts ceramic fragments, 6-8 parts heavy metal ion scavenging agent, 3-4 parts deodorizing agent, and 9-12 parts water. This invention utilizes domestic sewage sludge to prepare sludge bricks, reducing sludge disposal problems, avoiding the impact of domestic sewage sludge on the environment and human health, and achieving resource recycling. Furthermore, the preparation process defined in this invention reduces the generation and emission of waste gas, ensures that wastewater meets discharge standards, reduces environmental impact, and the prepared sludge bricks possess excellent mechanical properties, expanding their application prospects in building materials.

The present application relates to the technical field of photoresist, in particular to a photoresist composition, a preparation method and application thereof.A photoresist composition comprises the following components by mass percentage: phenolic resin 5-40%, photosensitive compound 1-20%, adhesion enhancer 0.01-2%, surface leveling agent 0.01-1% and organic solvent 55-90%; the photosensitive compound is selected from at least two of a first G-line photosensitive compound, a second G-line photosensitive compound and an I-line photosensitive compound; the adhesion enhancer is selected from melamine resin and / or silane coupling agent; and the surface leveling agent is selected from silicon compound and / or fluorocarbon compound.The photoresist composition has high development adhesion, good pattern angle and high sensitivity.

The application provides a preparation method of a polyamide reverse osmosis membrane, comprising the following steps: (1) immersing a non-woven fabric supported ultrafiltration membrane into an aqueous phase solution, and removing the excess aqueous phase solution on the surface of the ultrafiltration membrane after taking out; (2) immersing the ultrafiltration membrane obtained in the step (1) into an oil phase solution to perform interfacial polymerization, and then removing the excess oil phase solution on the surface of the ultrafiltration membrane; (3) coating an alcohol solution containing dansyl on the surface of the membrane obtained in the step (2), performing heat treatment, cleaning with hot water after the reaction is completed, and obtaining the reverse osmosis membrane. The amino group in dansyl reacts with acyl chloride and is grafted in the polyamide network. The tertiary amine in dansyl accepts protons in an acidic solution and shows hydrophilicity, which improves the hydration water content of the polyamide and the stability of the polyamide structure. The naphthalene group in dansyl occurs hydrophobic aggregation in an alkaline solution, which reduces the size and polarity of the polyamide hole, so that the polyamide reverse osmosis membrane with acid and alkali resistance and high boron removal is prepared.

This invention discloses a superhydrophobic fiber membrane with a wrinkled structure and its preparation method. The preparation method is as follows: immersing a polypropylene fiber membrane in a methanol solution of a photoinitiator; removing it and irradiating it under a UV lamp; then immersing it in a methanol solution of an amino monomer and irradiating it under a UV lamp; then immersing it in a hexane solution of an acyl chloride, removing it, and then immersing it in a methanol solution of a hydroxyl monomer for interfacial polymerization; removing it; drying it; immersing it in a hexane solution of a long-chain alkylchlorosilane, removing it, and drying it to obtain a superhydrophobic fiber membrane with a wrinkled surface structure. The method of this invention is simple, easy to implement, and operates under mild conditions, requiring no precision instruments. It offers fast separation speed, high efficiency, and good reusability. When used to separate water-in-oil emulsions containing surfactants, the wrinkled structure on the fiber membrane surface increases the contact area between the superhydrophobic surface and the emulsion, promoting the coalescence and demulsification of microemulsions, and achieving a water retention rate of over 99%.

The application belongs to the field of batteries and relates to a blended polymer full solid-state electrolyte containing nano-powder rubber, a preparation method of the blended polymer full solid-state electrolyte and a lithium ion battery. The full solid-state electrolyte comprises a polymer blend, a lithium salt and nano-powder rubber; the polymer blend comprises polyacrylonitrile and polypropylene carbonate; the weight content of the polymer blend is 25-70%, the weight content of the lithium salt is 20-50% and the weight content of the nano-powder rubber is 3-35% based on the total weight of the full solid-state electrolyte. The full solid-state electrolyte has higher conductivity and better cycle performance.

The invention discloses a metal-doped aluminum oxide supported alkaline catalyst as well as a preparation method and application thereof. The catalyst comprises a carrier and an alkaline component supported on the carrier, the carrier contains Al2O3 (aluminum oxide), AgxOy (silver oxide) and RemOn (iron oxide); agxOy is selected from one or more of elemental Ag and Ag oxide; remOn is selected from one or more of elemental Re and Re oxides; the alkaline component is selected from one or more of alkali metal, alkaline earth metal and organic alkaline compounds. According to the present invention, the catalyst carrier contains Al2O3, AgxOy and RemOn, and through the synergistic effect of the AgxOy and the RemOn in different forms, the loaded alkaline component and the optional modification component, the performance of the catalyst is significantly improved, such that the catalyst has the good catalytic performance, can achieve the adsorption removal and refining of different organic sulfur and inorganic sulfide under the low temperature condition, and has the good industrial application prospect. In addition, the catalyst can be regenerated repeatedly, and the preparation method of the catalyst is simple and easy to implement and convenient for industrial production.

This invention discloses hollow silver-platinum nanoalloy particles, their preparation method, and applications. The silver-platinum nanoalloy particles have a particle size of 30-60 nm, an overall hollow structure, and a porous surface distribution of silver and platinum fused together. The preparation method includes: using epigallocatechin gallate as the sole reducing agent and stabilizer, reducing silver nitrate in ethylene glycol to prepare monodisperse silver nanoparticles; then, at 60-80°C, slowly adding chloroplatinic acid solution in batches to the silver nanoparticle solution to carry out an in-situ exchange reaction; after the reaction, washing and separation yields the final product. This invention provides a green, simple, mild, and highly controllable preparation method. The prepared silver-platinum nanoalloy particles simultaneously possess excellent nanozyme catalytic activity and high-sensitivity surface-enhanced Raman scattering performance, achieving integrated synergistic catalytic and detection functions. It has broad application prospects in food safety testing, environmental monitoring, and biosensing.

The invention provides a lithium metal composite negative electrode, a preparation method thereof and a solid-state battery. The lithium metal composite negative electrode is of a multi-layer structure and sequentially comprises a current collector, a buffer binding layer, an active substance layer and an interface enhancement layer, the buffer binding layer is a conductive buffer material layer, the active substance layer is a lithium metal and / or lithium alloy layer, and the interface enhancement layer is a lithium metal and / or lithium alloy layer. The interface enhancement layer is a layer which contains an MOFs material, a lithium salt and an organic polymer material and has a three-dimensional porous structure. In the interface enhancement layer, an organic polymer material improves the surface mechanical strength of the negative electrode, improves the ionic conductivity and inhibits lithium metal expansion; the MOFs has a three-dimensional porous structure and can store a large number of lithium ions, accelerate ion conduction, regulate and control uniform deposition of metal lithium on the surface of the negative electrode and effectively inhibit growth of lithium dendrites on the surface of the negative electrode. The interface enhancement layer improves the compatibility between the lithium metal and the solid electrolyte, reduces the generation of side reactions, improves the cycle performance of the metal lithium solid-state battery and prolongs the service life of the metal lithium solid-state battery.

This invention belongs to the field of photocatalyst materials technology, specifically relating to a three-dimensional graphene aerogel photo-self-propelled Fenton catalyst, its preparation method, and its application. The preparation method includes: mixing a graphene dispersion containing ethylenediamine with a phenolic resin prepolymer containing ferrocene, phenols, and an alkaline catalyst; followed by a one-step hydrothermal reaction, washing, and freeze-drying to obtain the three-dimensional graphene aerogel photo-self-propelled Fenton catalyst. This catalyst can be used to degrade organic pollutants in water under visible light irradiation.

This invention relates to the field of shape memory alloy technology, specifically providing a zero-hysteresis giant linear elastic Ni-Fe-Ga shape memory alloy microwire and its preparation method. The preparation method of the alloy microwire includes: ① preparing austenitic alloy microwires using a glass coating method; ② inducing the austenite in the microwires into a full martensite structure through stress aging treatment and maintaining it at room temperature; ③ finally introducing some austenite into the martensite alloy microwires through annealing treatment, obtaining a wire material with a stable austenite / martensite coexistence structure at room temperature. The Ni-Fe-Ga ternary shape memory alloy microwires provided by this invention exhibit both zero hysteresis and giant linear elasticity characteristics under external force, with a maximum elastic strain of up to 7.7%, and the preparation method is simple, showing broad application prospects in high-precision micro-actuators and sensing fields.

This invention provides an impeller comprising: a cylindrical hub extending axially; and a plurality of blades extending radially outward from the hub and arranged circumferentially, wherein the impeller has a plurality of segmented impeller portions, each of the plurality of segmented impeller portions comprising: a segmented hub portion forming part of the hub; and at least one blade extending radially outward from the segmented hub portion forming part of the plurality of blades. In the impeller, one blade and another blade circumferentially adjacent to each other are part of different segmented impeller portions among the plurality of segmented impeller portions.

The application relates to a G-quadruplex RNA fluorescent ligand and a preparation method and application thereof, a structure formula of the G-quadruplex RNA fluorescent ligand is shown in the following formula: the compound can be specifically targeted and can be subjected to fluorescent imaging in a solution system and a cell system, a high-throughput fluorescent screening method is established in the solution and the cell system, and an organic small-molecule compound with strong binding capacity to G-quadruplex RNA can be effectively identified and screened from a small-molecule drug library; the screening result of the method is high in accuracy, the affinity and biological activity of a candidate compound can be quickly determined by evaluating the change of a fluorescent signal, and therefore the research and development process of an antitumor drug is accelerated; and the application belongs to the field of biological medicines.

The application discloses a kind of hydrophilic photo-thermal covalent organic framework nanofiber materials and preparation method thereof, belong to photo-thermal material and seawater desalination field.For the technical problem that existing photo-thermal material is difficult to consider high efficient light absorption and fast water transport, first, homogeneous polymerization method is used, monomer containing sulfonic acid group and porphyrin monomer etc. occur polycondensation reaction in acetic acid aqueous solution, and the photo-thermal covalent organic framework dispersion is obtained by dialysis purification;Subsequently, the dispersion is freeze-dried, and the hydrophilic photo-thermal covalent organic framework nanofiber is obtained.The material uses porphyrin big π bond system as photo-thermal conversion core, and uses the rich sulfonic acid group and regular pore channel in framework to build efficient water transport network.The preparation process of the application is mild and controllable, and the obtained material has excellent broadband light absorption and hydrophilic ability, and has broad application prospect in the field of solar-driven interfacial seawater desalination.

This invention discloses a method and its application for controlling the bending degree of a two-dimensional cobalt four-coordinate conjugated compound on a three-dimensional tubular carbon material. The specific procedure involves ultrasonically dispersing a three-dimensional honeycomb-structured tubular carbon material in methanol, and dispersing the two-dimensional cobalt four-coordinate conjugated compound in methanol. The dispersion of the two-dimensional cobalt four-coordinate conjugated compound is slowly added dropwise to the dispersion of the three-dimensional honeycomb-structured tubular carbon material, while magnetic stirring. The solution is filtered and washed with methanol. Finally, the resulting solid is dried in a vacuum drying oven to obtain a composite structure of the two-dimensional cobalt four-coordinate conjugated compound and the three-dimensional honeycomb-structured tubular carbon material. This invention modifies the bending strain of the two-dimensional cobalt four-coordinate conjugated compound on the three-dimensional honeycomb-structured tubular carbon material by controlling the diameter of the tubular material. The preparation method is simple, efficient, environmentally friendly, and low-cost.

The invention discloses a cross-linked polymer-molecular cluster non-fluorine composite proton exchange membrane and a preparation method and application thereof, the cross-linked polymer-molecular cluster non-fluorine composite proton exchange membrane is mainly prepared from branched polyethyleneimine (PEI), polyvinyl chloride (PVC) and phosphotungstic acid (PW12), quaternized PEI and PVC are subjected to a cross-linking reaction, and then the prepared membrane is immersed in a PW12 solution to prepare the cross-linked polymer-molecular cluster non-fluorine composite proton exchange membrane. Wherein the mass ratio of the PEI to the PVC can be adjusted as required, the mass fraction of the PW12 solution is preferably 5-20%, the proton exchange membrane has good mechanical properties, thermal stability and excellent proton conductivity, and the preparation method is simple, low in cost and environmentally friendly.

The application belongs to the field of functional substance research, and particularly relates to a corn extract for promoting GLP-1 secretion, and a preparation method and application thereof. The corn extract provided by the application is a dried product obtained by ultrasonic extraction of a dried powder of fresh corn kernels after room temperature soaking in ethanol or an ethanol aqueous solution; the fresh corn comprises yellow sweet corn; the temperature of the ultrasonic extraction is 30-60 DEG C; the power of the ultrasonic extraction is 50-150 W; and the time of the ultrasonic extraction is 30-90 min. The preparation method of the corn extract is simple and easy to implement, and can effectively reduce the production cost of functional ingredients. The corn extract can effectively promote the secretion of GLP-1 by intestinal L cells in both healthy and insulin-resistant states, and simultaneously improve cell viability.

The application discloses a preparation method of high-strength and high-ductility titanium-based composite material with a composition gradient, and comprises the following steps: 1, material selection: selecting a plurality of Mo equivalent different beta type titanium alloy powder as a matrix material, and selecting carbon nanoparticles as a precursor material of a reinforcing body; 2, powder mixing: placing the plurality of Mo equivalent different beta type titanium alloy powder and the carbon nanoparticles in a ball mill and ball milling and uniformly mixing; 3, forming: performing plasma sintering forming on the mixed powder; 4, heat treatment: performing solid solution treatment on a titanium-based composite material blank to obtain the high-strength and high-ductility titanium-based composite material with the composition gradient. The application utilizes a powder metallurgy method to sinter the plurality of Mo equivalent different beta type titanium alloy powder and the carbon nanoparticles into a bulk alloy, so that the sintered bulk alloy has the composition gradient, and the prepared titanium-based composite material with the composition gradient has excellent mechanical properties and is a high-strength and high-elongation composite material.

The utility model discloses a connecting and fixing device, which belongs to the technical field of aeronautical manufacturing and maintenance, and comprises a connecting piece A and a connecting piece B which have the same structure, fixing bases of the connecting piece A and the connecting piece B are used for being fixed on materials needing to be connected, and fastening parts in a hollow triangular prism shape are fixed on the lower parts of the fixing bases of the connecting piece A and the connecting piece B; the difference is that the size of the fastening part of the connecting piece B is smaller than that of the connecting piece A, so that the connecting piece B can be sleeved in the connecting piece A and then is fixedly connected through a fastening screw. According to the utility model, the situation that a common angle section needs to be fixed at a fixed angle in advance is avoided, the effective utilization of the space in the operation process is improved, and the connection mode has no limitation requirement on the space of the two materials.

The invention relates to the technical field of batteries, in particular to porous carbon. The invention provides porous carbon, the porous carbon comprises micropores, the percentage of the pore volume of the micropores in the total pore volume is greater than or equal to 85%, and in a pore distribution curve with the abscissa being the pore diameter and the ordinate being the differential pore volume dV / dW obtained by a nitrogen adsorption method test, the differential pore volume dV / dW of the porous carbon is greater than 0.05 cm < 3 >. G <-1 >. Nm <-1 > within the pore diameter range of 1-2nm. The porous carbon has proper microporosity and pore size distribution in Koelreuteria-shaped distribution, can effectively improve the silicon loading efficiency, reserves a part of space for volume enlargement caused by silicon expansion in the nanometer silicon circulation process, has the effect of relieving volume expansion when lithium is embedded into silicon, can reduce the volume expansion rate of the silicon-based negative electrode material, and improves the silicon-based negative electrode material performance. The cycling stability of the battery is improved.

The application provides a monolithic adsorbent based on 3D printing technology. The application selects halloysite nanotubes and hydroxypropyl methyl cellulose as binders. The halloysite nanotubes have excellent high-temperature resistance, hardness and durability, and chemical stability, and can meet the application requirements of the catalyst under high-temperature complex working conditions, so that the catalyst structure remains mechanical stability. The hydroxypropyl methyl cellulose has processability and plasticity, and can help to print complex shapes and structures. The super strong bonding force and interlayer adhesion can effectively bond the printing materials, ensure the firmness and stability of the interlayer adhesion in the printing process, and help to reduce the distortion and deformation in the printing process. The monolithic passive NO x adsorbent provided by the application has a simple and feasible preparation method, is a non-noble metal adsorbent with economic benefits, and can be connected in series with a downstream SCR treatment unit to realize ultra-low emission in the NOx cold start stage.

The invention discloses a porous composite membrane as well as a preparation method and application thereof. The porous composite membrane comprises an ion conduction layer and a high-strength layer; the thickness of the ion conduction layer is 30-70 [mu] m; the thickness of the high-strength layer is 4-15 microns; and the thickness of the porous composite membrane is 34-85 [mu] m. And the high-strength layer can further screen protons and metal ions, so that the coulombic efficiency of the battery is further improved. The membrane has excellent chemical stability, and provides a new direction for the design of a high-performance membrane of a flow battery. The preparation method is simple and easy to implement, and mass production is easy to realize. And the high-strength layer is not easy to fall off and has excellent mechanical properties.

This invention discloses a parallel-interface engineered viologen-based defective carbon nitride composite material, its preparation method, and its applications, belonging to the field of energy catalysis and photochemical materials technology. The material comprises: a defective graphitic carbon nitride support; single-atom platinum catalytic sites supported on the support; and a selenium-containing viologen compound anchored by covalent bonds in a configuration parallel to the support surface. Through a bilateral covalent bonding strategy, viologen molecules are stably anchored in a parallel configuration to the single-atom platinum-modified defective carbon nitride surface, constructing a highly efficient and stable "electron bridge" structure, significantly enhancing interfacial bonding and photogenerated electron transport efficiency. This composite material exhibits excellent photocatalytic hydrogen evolution activity and efficient coupling ability with benzylamine oxidation under visible light, and its activity retention rate reaches over 92% after 144 hours of cycling. It provides a new paradigm for solving the problem of poor interfacial stability in photocatalysts and has significant application prospects in the field of solar fuel synthesis.

The invention belongs to the field of macromolecules, and relates to an aerogel compound fertilizer, a biodegradable film and a preparation method and application thereof. The aerogel compound fertilizer comprises a bio-based high-molecular material carrier and a fertilizer loaded on the bio-based high-molecular material carrier, and is prepared by reacting a bio-based high-molecular material, an auxiliary agent and a water-soluble fertilizer, the bio-based high polymer material is a plant hormone; the auxiliary agent is a long-chain aliphatic compound and an N-vinyl amide polymer; based on 100 parts by weight of the aerogel compound fertilizer, the use amount of the bio-based high polymer material is 20-60 parts by weight, the use amount of the long-chain aliphatic compound is 1-10 parts by weight, the use amount of the N-vinyl amide polymer is 1-10 parts by weight, and the use amount of the water-soluble fertilizer is 10-80 parts by weight. The film prepared from the biodegradable composition disclosed by the invention has the characteristics of good mechanical property, good weather resistance, good fertilizer slow release performance, biodegradability and the like.

The invention discloses a preparation method of a reducing gas treatment layered positive electrode material, and belongs to the field of lithium ion batteries. The preparation method comprises the following steps: placing a layered positive electrode material in a reducing atmosphere, and carrying out high-temperature heat treatment to form the layered positive electrode material coated with surface oxygen vacancy defects and low-valence metal oxide. The preparation viscosity of the positive electrode material slurry can be reduced, the specific capacity of the layered positive electrode material is improved, the side reaction between the material and the electrolyte is reduced, the process is simple, and the operability is high.