Abstract: Embodiments relate to a base film that is colorless, transparent, and excellent in mechanical properties and optical properties, particularly with low moisture permeability, a process for preparing the same, and a cover window and a display device comprising the same. The cover window comprises a base film comprising a polyamide-based polymer and having a moisture permeability of 300 g/m2·day or less; and a functional layer.

Abstract: The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan ? over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 2.0 or less.

Abstract: Embodiments relate to a polyamide-based film that is colorless and transparent, is excellent in mechanical properties and optical properties, has a wide angle of view by securing at least a certain level of luminance at various angles, and, in particular, has gloss characteristics similar to those of glass, a process for preparing the same, and a cover window comprising the same. The polyamide-based film comprises a polyamide-based polymer, wherein when the polyamide-based film is placed on a surface light source, light is irradiated from the surface light source, and the luminance value (L0) measured in the normal direction of the surface light source is 100%, the luminance value (L50) measured in the direction of 50° from the normal direction of the surface light source is 25% or more.

Abstract: The present disclosure relates to a rubber composition for tire tread and a tire manufactured by using the rubber composition for the tire tread, and more specifically to, a rubber composition for tire tread, the rubber composition comprising: 100 parts by weight of a raw rubber; 50 to 200 parts by weight of a reinforcing filler; 5 to 100 parts by weight of a hydrocarbon-based resin; and 5 to 50 parts by weight of a hydrogenated styrene-butadiene rubber, and a tire manufactured by using the rubber composition for the tire tread.

Abstract: The present invention provides a novel diamine compound capable of producing a polymer which exhibits greatly enhanced mechanical properties and heat resistance while maintaining transparency. A film including a polymer produced using the diamine compound has excellent transparency, heat resistance, mechanical strength and flexibility, and thus can be used in various fields, such as in a device substrate, a display cover substrate, an optical film, an Integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), a tape, a touch panel and an optical disc protection film, and the like.

Abstract: The present invention relates to monodisperse silanized ferrimagnetic iron oxide particles, a method for producing the same and a method for independent generic binding of nucleic acid molecules to the particles.

Abstract: A composition comprising a cyclic olefin copolymer; a particulate filler dispersed in the cyclic olefin copolymer; and a solvent is disclosed. The composition can be used to make a transmissive composite. The transmissive composite and a method of making a transmissive composite panel are also disclosed.

Abstract: The present disclosure relates to a method for preparing aluminosilicate particles having excellent dispersion, a reinforcing material for rubber including the aluminosilicate particles, and a rubber composition for tires including the same. The reinforcing material for rubber including the aluminosilicate particles prepared by the method of the present disclosure can exhibit excellent dispersibility in the rubber composition and an enhanced reinforcing effect, so that it can be suitably used in eco-friendly tires requiring high efficiency and high fuel efficiency.

Abstract: Provided are an aqueous resin dispersion of an ethylene-vinyl alcohol copolymer exhibiting excellent dispersion stability, a production method for the aqueous resin dispersion, a hydrophilization agent including the aqueous resin dispersion, a hydrophilization method using the hydrophilization agent, a metal material on which a hydrophilic coating has been formed, and a heat exchanger on which a hydrophilic coating has been formed.

Abstract: A polypropylene resin composition includes: a base resin; a thermoplastic elastomer; and an inorganic filler; a major-axis diameter/minor-axis diameter, which is an aspect ratio of the inorganic filler, is 2 to 8. A molded product includes an injection molding of the polypropylene resin composition. The polypropylene resin composition may simultaneously impart excellent rigidity, impact resistance, and excellent dimensional stability even when applied to a molded product having a small thickness, while maintaining a low specific gravity.

Abstract: The present invention relates to a method of preparing a thermoplastic resin. More particularly, the present invention relates to a method of preparing a thermoplastic resin, the method including a coagulation step of adding a water-soluble silicate compound and a metal salt coagulant to an ?-methylstyrene-vinyl cyan compound copolymer latex, followed by coagulation. In accordance with the present invention, a method of preparing a thermoplastic resin having superior heat resistance by adding an additive during coagulation and aging of ?-methylstyrene-vinyl cyan compound copolymer latex while controlling an addition time point of the additive is provided.

Abstract: A fiber reinforced thermoplastic resin molding material includes a thermoplastic resin; a resin impregnated reinforcing fiber filament obtained by impregnating reinforcing fibers with a resin having a melt viscosity at 200° C. lower than a melt viscosity of the thermoplastic resin; and a reinforcing fiber modifier having a melt viscosity at 200° C. lower than the melt viscosity of the thermoplastic resin and a difference in solubility parameter value from the thermoplastic resin equal to or larger than 1.0, the molding material including 50 to 98.9 parts by weight of the thermoplastic resin; 1 to 40 parts by weight of the reinforcing fiber; 0.1 to 10 parts by weight of the reinforcing fiber modifier; and 0.2 to 12 parts by weight of the resin relative to total 100 parts by weight of the thermoplastic resin, the reinforcing fiber, and the reinforcing fiber modifier.

Abstract: A flame-retardant flexible polymer composition includes a polymer component that contains 98 to 80 parts by mass of a chlorinated polyethylene and 2 to 20 parts by mass of a polyolefin polymer; and calcium hydroxide particles having a surface containing calcium silicate, wherein a content of the particles relative to 100 parts by mass of the polymer component is 5 parts by mass or more and 20 parts by mass or less. A polymer tube is formed from the flame-retardant flexible polymer composition. An insulated wire includes an insulation formed from the flame-retardant flexible polymer composition.

Abstract: Provided are a polyamic acid resin, a polyamideimide film, and a method for preparing the same. More specifically, provided are a polyamic acid resin derived from a combination of specific components, and a polyamideimide film capable of implementing high modulus and excellent optical properties.

Abstract: A composition comprising a cyclic olefin copolymer; a particulate filler dispersed in the cyclic olefin copolymer; and a solvent is disclosed. The composition can be used to make a transmissive composite. The transmissive composite and a method of making a transmissive composite panel are also disclosed.

Abstract: A copolymerized polysilazane comprising at least repeating units represented by general formula (I): —Si(R1)(R2)—NR3— and repeating units represented by general formula (II): —Si(R1)(R2)—NH— (in the formulas, R1 and R2 each independently represent a hydrogen atom, hydrocarbon group, hydrocarbon group-containing silyl group, hydrocarbon group-containing amino group, or hydrocarbon oxy group, and R3 represents an alkyl group, alkenyl group, alkoxy group, cycloalkyl group, aryl group or alkyl silyl group), and the NR3/SiH1,2 ratio (SiH1,2 represents the total amount of SiH1 and SiH2) is 0.005-0.3. Said copolymerized polysilazane can be manufactured by reacting Si(R1)(R2)X2 (in the formula, X represents a halogen atom) with a primary amine compound: R3NH2 and then reacting with ammonia, and is able to form a siliceous film that has withstand voltage characteristics and solvent resistance by curing at a low temperature.

Abstract: A method of preparing a polymer dispersion comprising (i) contacting an aqueous dispersion of de-ionized acidic colloidal silica particles with a first mixture of monomers to form a combination; (ii) polymerizing such combination at an initial pH of from 2 to 5 to at least 90% in completion; and (iii) adding a second mixture of monomers at a rate substantially equal to the rate of consumption of such second mixture of monomers to continue and complete the polymerization. The present invention further provides a polymer dispersion made from the above method.

Abstract: A mortar mixture for horizontal surfaces or as casting mortar in molds has at least 20% of the mortar mixture by volume being balls composed of expanded silica sand or expanded perlite with the balls being glazed and closed at the surface thereof and filled with air. The expanded perlite balls are mixed with binding agents, additives as binders, an air-void forming agent, chemical admixtures as liquefiers, quick-setting binders, or a combination thereof, and composed of polymers. The method for producing the mortar mixture is performed by sorting perlite sand into various grain sizes by a grading curve. Each individual grain size is then expanded in a trickling channel having multi-stage temperature zones so that the surface of the balls is glazed. The glazed, expanded perlite so produced are mixed together into a homogenous mixture by adding binding agents and cellulose, air-void forming agent, chemical admixtures or a combination thereof.

Abstract: The present invention describes a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table, supported on a hybrid catalytic support provided with aliphatic organic groups, and a process for supporting metallocene on the hybrid catalytic support. The supported metallocene catalyst provides an ethylene polymer with broad or bimodal molecular weight distribution, in the presence of only one metallocene complex on the support.

Abstract: The present invention describes a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table, supported on a hybrid catalytic support provided with aliphatic organic groups, and a process for supporting metallocene on the hybrid catalytic support. The supported metallocene catalyst provides an ethylene polymer with broad or bimodal molecular weight distribution, in the presence of only one metallocene complex on the support.

Abstract: A method for producing high-molecular weight, solid, meltable, thermoplastic, pre-ceramic polymers by converting liquid low-molecular weight polysilazanes in a solvent, in the presence of a catalyst, and a stopping reagent stopping the reaction as soon as the desired degree of polymerization is achieved. The obtained polysilazanes can be processed by conventional industrial methods, such as, for example, extrusion, injection molding, melt spinning, calendering, film and hollow body blowing, rotational molding, fluidized bed sintering, flame spraying and transfer molding (RTM and DP RTM).

Abstract: The invention relates to a method for regenerating used foundry sand, which is contaminated with soluble glass, wherein: used foundry sand is provided, which is tainted with a binding agent made of the soluble glass, to which a particle-shaped metal oxide is added; and the used foundry sand is subjected to a thermal treatment, wherein the foundry sand is heated to a temperature of at least 200° C., thereby obtaining regenerated foundry sand. The invention further relates to regenerated foundry sand, as that obtained from using the method.

Abstract: The present invention is directed to a condensed phase batch process for synthesis of trisilylamine (TSA). An improved synthesis method that incorporates a solvent to help promote a condensed-phase reaction between ammonia gas (or liquid) and liquified monochlorosilane (MCS) in good yields is described. This method facilitates the removal of the byproduct waste with little to no reactor down time, substantial reduction of down-stream solids contamination and high-purity product from first-pass distillation.

Abstract: A method for producing a modified polymer or a hydrogenated product thereof, includes polymerizing a monomer in a polymerization solvent which includes a hydrocarbon-based solvent, using a polymerization initiator to obtain a reaction solution. A functional group is introduced into the modified polymer or the hydrogenated product thereof, using a compound having the functional group protected with a silyl group. The reaction solution is separated into a solvent fraction including the hydrocarbon-based solvent, and a solid fraction including the modified polymer or the hydrogenated product thereof. The solvent fraction separated from the reaction solution is distilled to obtain a low-boiling fraction including the hydrocarbon-based solvent and a silanol compound. At least part of the silanol compound is removed from the low-boiling fraction by liquid-liquid extraction. At least part of a raffinate of the low-boiling fraction is recycled as a polymerization solvent.

Abstract: The present invention relates to a thermoplastic polyolefin elastomer composition in powder form comprising an olefin block copolymer and optionally a high density polyethylene (HDPE), said composition having a Shore A hardness greater than 75, a Tg less than ?45° C., a distinct melting peak greater than 95° C., a zero shear viscosity equal to or less than 1,200 Pa-s and a particle size distribution wherein 85 percent of the particles fall between 150 microns to 420 microns and no particles are greater than 500 microns. Said composition demonstrates good pulverizing and flow characteristics at a temperature of 5° C. or less than the distinct melting peak of the olefin block copolymer. In another aspect, this invention relates to a process for preparing said thermoplastic polyolefin elastomer powder and applications for using said powder.

Abstract: The present invention provides a composition for treatment, the composition comprising dispersed in water (i) a fluorinated compound, (ii) a potassium or lithium silicate and (iii) an acrylic polymer. The invention further provides a method of treating substrates with the composition.

Abstract: Provided are a rubber composition improving wet-grip performance and its temperature dependence while ensuring good fuel economy, and a pneumatic tire including the composition. The composition includes, per 100% by mass of a rubber component: 5-55% by mass of an aromatic vinyl compound/conjugated diene compound copolymer (A) having an aromatic vinyl compound content of at least 5% by mass but less than 15% by mass and a vinyl bond content in a conjugated diene compound moiety of 10-70 mol %; and 5-75% by mass of an aromatic vinyl compound/conjugated diene compound copolymer (B) having an aromatic vinyl compound content of at least 15% by mass but less than 30% by mass and a vinyl bond content in a conjugated diene compound moiety of 10-70 mol %, and also includes, per 100 parts by mass of the rubber component, 10-150 parts by mass of a silica having a N2SA of 40-400 m2/g.

Abstract: The present invention relates to a rubber composition including a rubber component (A), a farnesene polymer (B) and silica (C).

Abstract: De-polluting, self-cleaning coating compositions are disclosed which comprise an organic binder having dispersed therein photocatalytic titanium dioxide particles substantially in anatase form which have an average crystallite size between about 1 nm and about 150 nm and which preferably have photocatalytic activity in the presence of visible light. Advantageously, the coatings of the invention do not require pre-activation to achieve high initial photocatalytic activity against pollutants in the air, such as NOx compounds.

Abstract: A composition for forming a silica layer, a method of manufacturing the composition, a silica layer prepared using the composition, and a method of manufacturing the silica layer, the composition including hydrogenated polysilazane, hydrogenated polysiloxazane, or a combination thereof, wherein a concentration of a sum of hydrogenated polysilazane and hydrogenated polysiloxazane having a weight average molecular weight, reduced to polystyrene, of greater than or equal to about 50,000 is about 0.1 wt % or less, based on a total amount of the hydrogenated polysilazane and hydrogenated polysiloxazane.

Abstract: Disclosed herein are high structured carbon blacks, methods of synthesis and treatment, and dispersions and inkjet ink formulations prepared therefrom. The carbon black can have the following properties: OAN?170 mL/100 g; and STSA ranging from 160 to 220 m2/g. The carbon black can also have the following properties: OAN?170 mL/100 g; and a ratio of STSA/BET surface area ranging from 0.7 to 1.

Abstract: A polymer concrete composition, preferably for decorative and shock resistant building structures and goods includes a binder based of polyfunctional unsaturated compounds, namely acrylated/methacrylated vegetable oil, preferably acrylated/methacrylated soybean oil in an amount of not less than 60 part by weight and at least one acrylatedmethacrylated monomer and/or oligomer in an amount of not more than 40 part by weight, and an aggregate blend. The polymer concrete composition based on acrylated/methacrylated vegetable oil has high wear and shock resistance with low shrinkage and can be used for prefabricated building decorative structures and particularly in civil engineering.

Abstract: In order to provide a rubber composition in which dispersibility of silica is improved and in which a viscosity of an unvulcanized rubber is lowered and a heat build-up improving effect of a vulcanized rubber is well exerted, and a tire prepared by using the rubber composition, the rubber composition is endowed with a constitution in which 100 parts by mass of at least one rubber component selected from natural rubber and/or diene base synthetic rubbers are compounded with 55 to 200 parts by mass of silica and 0.5 to 15 parts by mass of at least one of alkanolamines represented by the following Formula (I): [in Formula (I), R1 represents an alkyl group or an alkenyl group having 1 to 24 carbon atoms, and the above alkyl group and alkenyl group may be any of a linear group, a branched group and a cyclic group; m and n represent an average addition molar number, and m and n are numerical values which represent m+n=1 to 20].

Abstract: An aqueous resin composition with gas barrier properties contains (i) polyurethane resin having aurethane group and a urea group in a total concentration of 25 to 60% by weight and having a acid value of 5 to 100 mgKOH/g, (ii) a swelling inorganic layered compound (e.g., a water-swelling mica, and a montmorillonite), and (iii) a polyamine compound having an amine value of 100 to 1900 mgKOH/g. The polyurethane resin (i) is obtained by a reaction of (A) an aromatic, araliphatic or alicyclic polyisocyanate, (B) a polyhydroxyalkanecarboxylic acid, and at least one component selected from (C) a C2-8alkylene glycol and (D) a chain-extension agent (e.g., diamine, hydrazine and a hydrazine derivative), and neutralized with a neutralizing agent. The proportion of the acid group of the polyurethane resin (i) relative to the basic nitrogen atom of the polyamine compound (iii) is 10/1 to 1/5 as the equivalent ratio.

Abstract: An artificial marble includes unsaturated polyester resin (A), compound including silica (B), and luminescent pigment (C). An artificial marble according to a second embodiment includes about 70 to about 95% by weight of a non-luminescent base material (I) comprising unsaturated polyester resin (A), compound including silica (B), and organic/inorganic pigment (C) and about 5 to about 30% by weight of a luminescent amorphous pattern part (II) comprising unsaturated polyester resin (A), compound including silica (B), and luminescent pigment (D). An artificial marble according to a third embodiment includes unsaturated polyester resin (A), compound including silica (B), and amorphous luminescent chip (C).

Abstract: The present invention is directed to compositions useful for sealing substrates and substrates coated therewith. Additionally, methods of sealing and improving sealing performance using such compositions are provided.

Abstract: A low copper-containing friction material composition used for brake pad is provided, which consists of 4-6 parts of aramid fiber, 2-2.5 parts of tire powder, 5-6 parts of magnesia, 5-6 parts of red vermiculite, 8-10 parts of ceramic fiber, 3.5-5 parts of magnetite, 7-8 parts of boron-containing phenolic resin, 15-17 parts of calcium sulfate crystal whisker, 16-18 parts of potassium titanate, 15-17 parts of barite, 5.5-7 parts of flake graphite, 6-8 parts of friction powder of cashew nut oil, 6-8 parts of calcined petroleum coke, 1.5-2 parts of boron nitride, 5-7 parts of flake aluminum powder, 0.4-0.5 parts of pure copper fiber, and 0.4-0.6 parts of black silicon carbide. The friction material composition has low content of heavy metal, wherein the content of copper is lower than 0.5%, has a satisfactory high temperature and thermal decay resistant performance, long service life, good abrasion resistance and stable friction coefficient.

Abstract: A roll cover is produced, in particular for use in a machine for producing and/or processing a fibrous web such as a web of paper or cardboard. The roll cover includes least one layer of a resin matrix that is filled with at least one particulate filler. The filler particles are produced in a polymer component of the resin matrix and/or introduced into the resin matrix from a dispersion via matrix exchange.

Abstract: A composition that contains from 30 to 95 wt. %, based on the total weight of the composition, of a thermoplastic component and an effective amount of a flow-enhancing component. The effective amount of the flow-enhancing component reduces the viscosity of the composition by at least 10% compared to the viscosity of a composition comprising the thermoplastic component, but not an effective amount of the flow-enhancing component. The thermoplastic component is selected from the group consisting of polycarbonates, polyesters, and combinations thereof. The flow-enhancing component comprises b1) a component selected from the group consisting of metal oxides, metalloid oxides, metal alkoxides, metalloid alkoxides, and combinations thereof and b2) a mineral filler component. The weight ratio of component b1) to component b2) ranges from 1:25 to 25:1. A method for enhancing the flow of compositions comprising thermoplastic components is also disclosed.

Abstract: A method for protecting an organic flooring surface (e.g., VCT, wood, a synthetic laminate material, etc.) or a surface of another organic substrate includes applying a composition that includes a silicate and a siliconate to the organic substrate and, with the composition on the surface, burnishing the surface. In some embodiments, the composition may be applied to the surface for maintenance purposes (e.g., periodic cleaning and/or polishing, etc.). The silicate of the composition may include an alkali metal polysilicate, a colloidal silica, or any other suitable silicate. In addition to the silicate and siliconate, the composition may include, or even consist essentially of, acrylic latex, a silane coupling agent, and a solvent, such as ethylene glycol monobutyl ether. Such a composition may also include a leveling agent, such as a surfactant.

Abstract: Coatings includes about 60 weight percent to about 90 weight percent of one or more fluorinated polymers, about 1 weight percent to about 7 weight percent of one or more erosion resistant fillers about 3 weight percent to about 9 weight percent of one or more anticorrosive pigments, about 1 weight percent to about 4 weight percent of one or more thixotropic agents, and about 1 weight percent to about 4 weight percent of one or more porosity reducing filler materials.

Abstract: A composition for protecting a surface of an organic substrate, such as VCT, wood, or a synthetic laminate material, includes a silicate (i.e., an alkali metal polysilicate or colloidal silica) and a siliconate (e.g., a metal siliconate, such as an alkali metal methyl siliconate, etc.). In addition, the composition may include acrylic latex, a silane coupling agent, and a solvent, such as ethylene glycol monobutyl ether. Such a composition may also include a leveling agent, such as a surfactant. Organic substrates, such as VCT, wood, and synthetic laminate materials, with such a composition on their surfaces are also disclosed.

Abstract: The synthetic aggregate for use in concrete is a composite material of recycled plastic having a filler encapsulated in the plastic. The synthetic aggregate includes between 30% and 50% recycled shredded plastic, the balance being filler. The plastic may be linear low-density polyethylene (LLDPE). The filler can include red sand, fly ash and quarry fines. The synthetic aggregate is best used to make concrete with a water-to-cement ratio of at least 0.5. A method of making the synthetic aggregate includes the steps of mixing plastic with filler to form a homogenized mixture, compressing the homogenized mixture in a mold, melting the plastic in the homogenized mixture to form a composite sheet or slab, and shredding the composite sheet or slab to form either coarse or fine aggregates for use in making concrete.

Abstract: Among the various aspects of the present disclosure is the provision of a methods and compositions for the installation and formation of roads and construction materials. The use of base materials and stabilizing agent provide affordable roads and construction materials.

Abstract: It is an object of the present invention to provide an aqueous ethylene-vinyl alcohol-based copolymer dispersion which is excellent in long-term storage stability and in film-forming properties even when subjected to low-temperature or short-time drying or applied to give thick coats and can give coatings showing high gas barrier performance. The prevent invention is an aqueous ethylene/vinyl alcohol-based copolymer dispersion, which comprises: (A) an ethylene/vinyl alcohol-based copolymer with an ethylene content of 15-65 mole percent and a degree of saponification of not lower than 80 mole percent, (B) a base-neutralized ethylene/?,?-unsaturated carboxylic acid-based copolymer and (C) a polyvinyl alcohol with a degree of saponification of 75-100 mole percent and a degree of polymerization of 100-3500, the content of the polyvinyl alcohol (C) being 0.5-100 parts by weight per 100 parts by weight of the ethylene/vinyl alcohol-based copolymer (A).

Abstract: A stable, aqueous composition containing a crosslinked, nonionic, amphiphilic polymer capable of forming a yield stress fluid in the presence of a surfactant is disclosed. The yield stress fluid is capable of suspending insoluble materials in the form of particulates and/or droplets requiring suspension or stabilization.

Abstract: Antimony free flame retardant compositions are prepared by combining a polymer resin, certain halogenated polyphenylene ether flame retardants and a non-brominated phenoxy oligomer or polymer such as a poly-phenylene ether, aryloxyester, or aryloxycarbonate. The present antimony free flame retardant compositions also typically have more desirable physical properties than similar compositions comprising antimony trioxide and other flame retardant. In particular embodiments, ATO free flame retardant HIPS and PC/ABS compositions are provided.

Abstract: The invention relates to absorptive, crosslinked polymers which are based on partly neutralized, monoethylenically unsaturated monomers carrying acid groups wherein the absorptive crosslinked polymer may be coated with a thermoplastic polymer, and have improved properties, in particular in respect of their capacity for transportation of liquids in the swollen state, and which has a high gel bed permeability and high centrifuge retention capacity.

Abstract: The invention pertains to a method for making a polymer-additive composite particle from a dope by jet spinning the dope to obtain a pulp, fibril or fibrid, wherein the solvent of the dope is selected from N-methyl-2-pyrrolidone, N,N?-dimethylformamide, N,N?-dimethylacetamide, tetramethylurea, and 4 to 75 wt % of a composition consisting of 2 to 95 wt % of a para-aramid polymer and 5-98 wt % of a solid additive material, to a total of 100 wt %, and wherein the aramid polymer is dissolved in the solvent; or coagulating the dope by means of a rotor-stator apparatus in which the polymer solution is applied through the stator on the rotor so that the precipitating polymer-additive composite particle is subjected to shear forces while they are in a plastic deformable stage.

Abstract: The present invention relates, in one aspect, to an adduct of formula O-PF-A, in which O is an oil; PF is a perfluoropolyether phosphate (PFPE phosphate); A is at least one substance selected from: (X) a water-soluble polyhydroxylated substance and (Y) a water-insoluble inorganic substance and to topical applications thereof in particular in the cosmetic and pharmaceutical field.