Abstract: An annealing process for treatment of an aluminum alloy of AA5XXX series which comprises steps of annealing the aluminum alloy at a first temperature of from about 350° C. to about 450° C. by a rate of temperature increase from about 0.1° C./s to about 0.5° C./s; and cooling down the annealed aluminum alloy to a temperature below 50° C. Aluminum alloys of the AA5XXX series treated by the annealing process of the present invention are also provided.

Abstract: Provided are Ce/Co/Cu permanent magnet alloys containing certain refractory metals, such as Ta and/or Hf, and optionally Fe which represent economically more favorable alternative to Sm-based magnets with respect to both material and processing costs and which retain and/or improve magnetic characteristics useful for GAP MAGNET applications.

Abstract: A method for producing a component made of a steel product coated with an Al—Si protective coating, includes: providing a substrate consisting of a steel produced coated with an Al—Si protective coating, heating the substrate to a temperature T1 such that the Al—Si protective coating is only partially pre-alloyed with Fe of the steel product, cooling the pre-alloyed substrate to room temperature, applying a corrosion protection oil to the surface of the pre-alloyed substrate, wherein the oil consists of a composition containing fatty acid ester, transporting the pre-alloyed substrate to which the oil has been applied, heating the pre-alloyed substrate to which the oil has been applied to a temperature T2 such that the Al—Si protective coating is fully alloyed with Fe of the steel product and the oil is removed without leaving residue, and shaping the re-heated substrate to form the component.

Abstract: An insulated bearing includes an outer ring, an inner ring, and a plurality of rolling elements. At least one of the outer ring and an inner ring is made of metal, the plurality of rolling elements are provided between the outer ring and the inner ring, so as to be freely rolled, and at least one of the outer ring and an inner ring is coated with an insulating layer. The insulating layer is formed of a mixture in which silicon carbide and/or aluminum nitride as an additive are/is dispersed in aluminum oxide as a base matrix. The content of the additive is 1 to 40 mass % with respect to the total amount of the mixture.

Abstract: Methods of processing thin film by oxidation at high pressure are described. The methods are generally performed at pressures greater than 2 bar. The methods can be performed at lower temperatures and have shorter exposure times than similar methods performed at lower pressures. Some methods relate to oxidizing tungsten films to form self-aligned pillars.

Abstract: The disclosure relates to the field of vapor-plating technologies, and discloses a mask strip, a mask, and a vapor-plating device to thereby improve the quality of vapor plating. The mask strip includes solder holes for soldering on a upper surface of a frame of a mask, and a first groove which is on the sides of the solder holes away from the upper surface of the frame, and communicates with the solder holes.

Abstract: At least one embodiment of the present disclosure provides a mask, an evaporation device and an apparatus. The mask includes at least one first mask strip and at least one second mask strip intersected with each other, wherein the mask is configured to form a component of an apparatus and includes a mask pattern for forming the component, and in an intersection region of the first mask strip and the second mask strip, the first mask strip and the second mask strip together constitute a portion of the mask pattern.

Abstract: There have been cases where transistors formed using oxide semiconductors are inferior in reliability to transistors formed using amorphous silicon. Thus, in the present invention, a semiconductor device including a highly reliable transistor formed using an oxide semiconductor is manufactured. An oxide semiconductor film is deposited by a sputtering method, using a sputtering target including an oxide semiconductor having crystallinity, and in which the direction of the c-axis of a crystal is parallel to a normal vector of the top surface of the oxide semiconductor. The target is formed by mixing raw materials so that its composition ratio can obtain a crystal structure.

Abstract: Provided is a sputtering target which can lower a heat treatment temperature for ordering a Fe—Pt magnetic phase and can suppress generation of particles during sputtering. The sputtering target is a nonmagnetic material-dispersed sputtering target containing Fe, Pt and Ge. The sputtering target includes at least one magnetic phase satisfying a composition represented by (Fe1-?Pt?)1-?Ge?, as expressed in an atomic ratio for Fe, Pt and Ge, in which ? and ? represent numbers meeting 0.35???0.55 and 0.05???0.2, respectively. The magnetic phase has a ratio (SGe30mass%/SGe) of 0.5 or less. The ratio (SGe30mass%/SGe) is an average area ratio of Ge-based alloy phases containing a Ge concentration of 30% by mass or more (SGe30mass%) to an area ratio of Ge (SGe) calculated from the entire composition of the sputtering target, in element mapping by EPMA of a polished surface obtained by polishing a cross section perpendicular to a sputtering surface of the sputtering target.

Abstract: A novel method, composition and storage and delivery container for using antimony-containing dopant materials are provided. The composition is selected with sufficient vapor pressure to flow at a steady, sufficient and sustained flow rate into an arc chamber as part of an ion implant process. The antimony-containing material is represented by a non-carbon containing chemical formula, thereby reducing or eliminating the introduction of carbon-based deposits into the ion chamber. The composition is stored in a storage and delivery vessel under stable conditions, which includes a moisture-free environment that does not contain trace amounts of moisture. The storage and delivery container is specifically designed to allow delivery of high purity, vapor phase antimony-containing dopant material at a steady, sufficient and sustained flow rate.

Abstract: Several embodiments of the present technology are directed to actively controlling a temperature of a substrate in a chamber during manufacturing of a material or thin film. In some embodiments, the method can include cooling or heating the substrate to have a temperature within a target range, depositing a material over a surface of the substrate, and controlling the temperature of the substrate while the material is being deposited. In some embodiments, controlling the temperature of the substrate can include removing thermal energy from the substrate by directing a fluid over the substrate to maintain the temperature of the substrate within a target range throughout the deposition process.

Abstract: An evaporator includes at least one feeding member and a heating member. Each feeding member is configured to transfer a source material in a transfer speed that is adjustable, and the heating member is configured to heat the source material transferred by the feeding member for evaporation to thereby generate a source material vapor. An evaporation coating apparatus further includes a coating chamber, an object holder, and a controller configured to control the transfer speed, wherein the evaporator and the object holder are both disposed inside the coating chamber, the object holder is configured to provide a platform for placing an object to be coated thereon, and the coating chamber is configured to provide an environment for the source material vapor vented out from the evaporator to attach to the object to thereby form a film of the source material onto the object.

Abstract: A method for Neutral Beam irradiation derived from gas cluster ion beams and articles produced thereby including optical elements.

Abstract: A method for depositing tungsten includes arranging a substrate including a titanium nitride layer in a substrate processing chamber and performing multi-stage atomic layer deposition of tungsten on the substrate using a precursor gas includes tungsten chloride (WCIx) gas, wherein x is an integer. The performing includes depositing the tungsten during a first ALD stage using a first dose intensity of the precursor gas, and depositing the tungsten during a second ALD stage using a second dose intensity of the precursor gas. The first dose intensity is based on a first dose concentration and a first dose period. The second dose intensity is based on a second dose concentration and a second dose period. The second dose intensity is 1.5 to 10 times the first dose intensity.

Abstract: Methods of selectively depositing ruthenium are described. The preferred deposition surface changes based on the substrate temperature during processing. At high temperatures, ruthenium is deposited on a first surface of a conductive material over a second surface of an insulating material. At lower temperatures, ruthenium is deposited on an insulating surface over a conducting surface.

Abstract: A diazadienyl compound represented by General Formula (I) below: wherein R1 represents a C1-6 linear or branched alkyl group, and M represents nickel atom or manganese atom. In particular, since a compound in which R1 in General Formula (I) is a methyl group has a high vapor pressure and a high thermal decomposition starting temperature, the compound is useful as a raw material for forming a thin film by a CVD method or ALD method.

Abstract: A method of manufacturing a material including tantalum carbide (TaC) with a particularly low impurity content, and a TaC material formed by the method are provided. The method includes preparing a base material, and forming a TaC coating layer on a surface of the base material at a temperature of 1,600° C. to 2,500° C.

Abstract: The present disclosure generally relate to thin films incorporating high aspect ratio feature definitions and methods for forming the same. As gate height increases, 3D NAND gate stacks are subject to higher aspect ratio etching. Due to the current limitations of etching techniques, the vertical etch profile typically tapers as the depth into the gate stack increases. The inventors have devised a unique deposition scheme that compensates for etch performance degradation in deep trenches by a novel plasma-enhanced chemical vapor deposition (PECVD) film deposition method. The inventors have found that by grading various properties (e.g., refractive index, stress of the film, dopant concentration in the film) of the as-deposited films (e.g., silicon nitride) a more uniform etch profile can be achieved by compensating for variations in both dry and wet etch rates.

Abstract: Described are multi-layer coatings, substrates (i.e., articles) coated with a multi-layer coating, and methods of preparing a multi-layer coating by atomic layer deposition, wherein the coating includes layers alumina and yttria.

Abstract: A plasma atomic layer deposition apparatus capable of improving a film quality of a film formed on a substrate is provided. The atomic layer deposition apparatus is a plasma atomic layer deposition apparatus configured to form the film on the substrate is in an atomic layer unit by generating plasma discharge between a lower electrode BE holding the substrate 15 and a facing upper electrode UE, and has a deposition prevention member CTM made of an insulator surrounding the upper electrode UE but being away therefrom in a plan view.

Abstract: Forming a protective coating ex situ in an atomic layer deposition process to coat one or more chamber components subsequently installed in a reaction chamber provides a number of benefits over more conventional coating methods such as in situ deposition of an undercoat. In certain cases the protective coating may have a particular composition such as aluminum oxide, aluminum fluoride, aluminum nitride, yttrium oxide, and/or yttrium fluoride. The protective coating may help reduce contamination on wafers processed using the coated chamber component. Further, the protective coating may act to stabilize the processing conditions within the reaction chamber, thereby achieving very stable/uniform processing results over the course of processing many batches of wafers, and minimizing radical loss. Also described are a number of techniques that may be used to restore the protective coating after the coated chamber component is used to process semiconductor wafers.

Abstract: There is provided a substrate processing apparatus including a process chamber in which a substrate is accommodated, a processing gas supply system configured to introduce a processing gas containing hydrogen peroxide into the process chamber and an exhaust system configured to exhaust an interior of the process chamber, wherein at least one selected from the group of the process chamber, the processing gas supply system, and the exhaust system includes a metal member, the metal member exposed to the processing gas or a liquid generated by liquefying the processing gas is made of a material containing an iron element, and a surface of a plane of the metal members, which is exposed to the processing gas or the liquid, is formed of a layer containing iron oxide which is formed by performing a baking process on the metal member.

Abstract: A thin film deposition apparatus is provided. The thin film deposition apparatus prevents powders from being generated by a gas supply unit for supplying process gas when a thin film is deposited by atomic layer deposition (ALD).

Abstract: A source gas supply unit includes a canister including a precursor accommodating space therein, and an inflow surface and an outflow surface which are open. The source gas supply unit includes a first lid configured to seal the inflow surface of the canister and having a gas inlet connected to the precursor accommodating space and a second lid configured to seal the outflow surface of the canister and having a gas outlet connected to the precursor accommodating space. The source gas supply unit includes a ring-shaped solid precursor located in the precursor accommodating space and including a gas flow path therein, which communicates with the gas inlet and the gas outlet. A cross-sectional area of the gas flow path increases from the inflow surface of the canister toward the outflow surface thereof.

Abstract: The invention is directed to a vaporizer or ampoule assembly with an improved vaporizer vessel body and support tray assembly configuration located therein that together increase the vaporizable material utilization and uniformity.

Abstract: A film formation apparatus includes a rotary table provided in a processing container; a mounting table mounting a substrate and revolved by rotation of the rotary table; a film formation gas supply part configured to supply a film formation gas to a region through which the mounting table passes by the rotation of the rotary table; a spinning shaft rotatably provided on a portion rotating together with the rotary table; a driven gear provided on the spinning shaft; a driving gear configured to rotate while facing a revolution orbit of the driven gear and provided along an entire circumference of the revolution orbit so as to constitute a magnetic gear mechanism with the driven gear, and a relative-distance-changing mechanism configured to change a relative distance between the revolution orbit of the driven gear and the driving gear.

Abstract: A method includes: forming an n-type diffusion layer as a second-conductivity-type semiconductor layer on a first-conductivity-type crystalline semiconductor substrate; and forming an anti-reflective film by a CVD method to extend from a light receiving surface side to a side surface of the semiconductor substrate, by placing the semiconductor substrate on a mount in a film forming chamber with a back surface brought into contact with the mount, evacuating and decompressing the film forming chamber, and supplying source gas into the film forming chamber. In the film formation, a tray has a through hole, and the anti-reflective film is formed on the surface of the semiconductor substrate excluding the contact surface by bringing the semiconductor substrate into close contact with the contact surface by causing the through hole to have a negative pressure relative to the pressure in the film forming chamber by the evacuation.

Abstract: A susceptor device for a chemical vapor deposition (CVD) reactor including metal organic CVD (MOCVD) used in the semiconductor industry. The susceptor device particularly is used with induction heating and includes a horizontal plate adapted for holding one or more wafers and a vertical rod around which the induction heating coils are disposed. A screw system and an insulator can further be used. This design helps prevent undesired levitation and allows for the gas injectors of the reactors to be placed closer to the wafer for deposition during high-temperature deposition processes at susceptor surface temperatures of about 1500° C. or higher.

Abstract: Described examples include a method of fabricating a gas cell, including forming a cavity in a first substrate, providing a nonvolatile precursor material in the cavity of the first substrate, bonding a second substrate to the first substrate to form a sealed cavity including the nonvolatile precursor material in the cavity, and activating the precursor material after or during forming the sealed cavity to release a target gas inside the sealed cavity.

Abstract: A compositionally-graded thin film is formed on a substrate by atomic layer deposition. A mixing system provides a homogeneous gaseous mixture having a controllable ratio of first and second reactive gaseous species. The first and second reactive gaseous species each react with a third reactive gaseous species but do not react with each other. A deposition unit includes first and second reactive gas zones. The homogeneous gaseous mixture is provided to the first reactive gas zone, and the third reactive gaseous species is provided to the second reactive gas zone. The mixing system is controlled to change the ratio of the first and second reactive gaseous species as a function of time as the substrate is moved relative to the deposition unit such that the deposited material has a variable composition as a function of height above the substrate.

Abstract: A spatial atomic layer deposition system is provided to fabricate a compositionally-graded thin film. A mixing system provides a homogeneous gaseous mixture having a controllable ratio of first and second reactive gaseous species. The first and second reactive gaseous species each react with a third reactive gaseous species but do not react with each other. A deposition unit includes first and second reactive gas zones. The homogeneous gaseous mixture is provided to the first reactive gas zone, and the third reactive gaseous species is provided to the second reactive gas zone. The mixing system is controlled to change the ratio of the first and second reactive gaseous species as a function of time as the substrate is moved relative to the deposition unit such that the deposited material has a variable composition as a function of height above the substrate.

Abstract: A method and apparatus for subjecting a surface of a substrate to successive surface reactions of precursors according to the principles of atomic layer deposition. The method including subjecting the surface of the substrate to the first precursor in a first precursor zone and subjecting the surface of the substrate to the second precursor in a second precursor zone. The method further includes changing the first precursor in the first precursor zone to a subsequent precursor which is different than the first and second precursors and subjecting the surface of the substrate to the subsequent precursor in the first precursor zone and subjecting the surface of the substrate to the second precursor in the second precursor zone.

Abstract: A method and an apparatus for coating a substrate by subjecting a surface of the substrate to successive surface reactions of a first precursor and a second precursor in a reaction chamber. The method includes the steps of arranging the substrate to the substrate support in the reaction zone; supplying a predetermined amount of the first precursor to the reaction chamber for providing a flow of the first precursor to the reaction zone; supplying the second precursor for providing a flow of the second precursor through the reaction zone and discharging the second precursor from the reaction chamber, the second precursor being inactive to react with the first precursor; generating plasma discharge to the reaction zone for forming active precursor radicals from the second precursor supplied into the reaction zone, the active precursor radicals being active to react with the first precursor.

Abstract: A thin-film optical device is formed on a substrate by atomic layer deposition. A mixing system provides a homogeneous gaseous mixture having a controllable ratio of first and second reactive gaseous materials. The first and second reactive gaseous materials each react with a third reactive gaseous material but do not react with each other. The homogeneous gaseous mixture is provided to a first inlet port, the third reactive gaseous material is provided to a second inlet port, and an inert gaseous material is provided to a third inlet port. The gas flows are directed through corresponding output channels of the delivery head toward the substrate. The mixing system is controlled to change the ratio of the first and second reactive gaseous materials as a function of time as the substrate is moved relative to the delivery head with an oscillating motion such that deposited layers have a varying composition.

Abstract: An atomic layer deposition apparatus is provided. The apparatus includes a gas supply module for simultaneously providing atomic layer deposition gases including a source gas, a purge gas and a reaction gas on different regions of deposition target substrate, and a stage disposed on a side of the gas supply module and configured to move the deposition target substrate in a linear direction. At least 2 layers of the atomic layer are deposited on the deposition target substrate as moving the deposition target substrate in the linear direction along the stage at 1-cycle.

Abstract: There is provided a vertical heat treatment apparatus for forming a film by supplying a precursor gas to a plurality of substrates that are held in a substantially horizontal posture on a substrate holder with a predetermined interval in a vertical direction. The apparatus includes a processing container including an inner tube accommodating the substrate holder and an outer tube that is disposed outside the inner tube; and a gas nozzle that extends vertically along an inner peripheral surface of the inner tube and has a distal end that penetrates from an inside of the inner tube to an outside of the inner tube. A first gas hole for supplying the precursor gas to the inside of the inner tube and a second gas hole for supplying the precursor gas to the outside of the inner tube are formed on the gas nozzle.

Abstract: The invention provides a thin film deposition system and a method, and relates to the field of thin film deposition. The deposition method comprises the following steps: 1) heating metal substrate; carrying out deposition. The method is characterized in the step 1) that a current is conducted into the metal substrate at one end of the growth zone by one electrode, and out of the metal substrate at the other end of the growth zone by the other electrode, so that the metal substrate is heated by the heat emitting of the resistant of the metal substrate itself. According to the method, the quality of the prepared thin film is improved, while the preparation cost of the thin film is reduced. In addition, the consistent double-sided thin films can be easily prepared on two surfaces of the metal substrate by employing the system and method.

Abstract: Disclosed herein is a drum for roll-to-roll deposition to rotate about a longitudinal axis. The drum is circular in a widthwise cross-section and has a shape in which opposite longitudinal edge portions each have a narrower width than a longitudinal central portion. By using the drum for roll-to-roll deposition according to embodiments of the present disclosure, it is possible to remove wrinkles occurring on a flexible substrate when a roll-to-roll deposition process is performed. As a result, it is possible to manufacture a film roll having a deposition layer with excellent widthwise thickness uniformity.

Abstract: Method for metallising a porous structure made of carbon material, the method comprising the following steps: supplying a porous structure made of carbon material, immersing the porous structure in a solution comprising an ionic liquid, formed by a cation and an anion, and a metal precursor, placing the porous structure in a vacuum, immersed in the solution, in such a way as to cause the solution to penetrate into the porosity of the porous structure, adding a hydrogenated reducing agent, in such a way as to metallise the porous structure to within the porosity of the porous structure.

Abstract: A grain-oriented electrical steel sheet according to one embodiment of the present invention includes a steel sheet and an insulation coating, in which the insulation coating contains a first metal phosphate, which is a metal phosphate of one or two more metals selected from Al, Fe, Mg, Mn, Ni, and Zn; a second metal phosphate, which is a metal phosphate of one or two more metals selected from Co, Mo, V, W, and Zr; and colloidal silica, the insulation coating does not contain chromate, and an elution amount of phosphoric acid of the insulation coating as determined by boiling the grain-oriented electrical steel sheet in a boiled pure water for 10 minutes, then measuring an elution amount of phosphoric acid into the pure water, and dividing the amount of phosphoric acid by the area of the insulation coating of the boiled grain-oriented electrical steel sheet is 30 mg/m2 or less.

Abstract: A receiver unit for accepting a multitude of oblong bodies in a treatment tank for treating the surface of the oblong bodies, particularly tubes, via a treatment medium which can be inserted into the treatment tank, enabling the receiver unit to move between an open position, in which the oblong bodies can be inserted into the receiver unit and can be removed from the receiver unit, and a closed position in which it forms a guide opening for the treatment medium, at least partially surrounding the oblong bodies.

Abstract: This disclosure relates to compositions for protecting a metallic surface susceptible to corrosion, the composition comprising a first component comprising an aqueous mixture of an acid-phosphate of chemical formula Am(H2PO4)m.nH2O, where A is hydrogen ion, ammonium cation, metal cation, or mixtures thereof where m=1-3, and n=0-6; the first component solution adjusted to a pH of about 2 to about 5, the first component having a particle size distribution between 0.04 to 60 micron; and a second component, configured for combination and at least partial reaction with the first component to provide a phosphate ceramic, the second component comprising an aqueous solution or suspension of an alkaline oxide or alkaline hydroxide represented by B2mOmB(OH)2m, or mixtures thereof, where B is an element of valency 2m (m=1, 1.5, or 2) the second component solution adjusted to a pH of between 9-14.

Abstract: Disclosed is a surface anti-corrosion treatment method for stainless steel. The method comprises the following steps: (1) performing chemical de-oiling and alkaline corrosion treatments on the surface of stainless steel by using a sodium hydroxide solution and a solution containing an alkaline corrosion active agent, and then washing with water; (2) performing, by using an oxidation solution, an oxidation treatment on the surface of the stainless steel treated in step (1), and then washing with water; (3) using the surface of the stainless steel treated in step (2) as a cathode and soaking same in an electrolyte for electrolysis, and then washing with water; and (4) placing the surface of the stainless steel treated in step (3) at a temperature of 50° C.-60° C. under a humidity of 60%-70%, and performing a hardening treatment. Also disclosed are the use of the treatment method in the treatment of a stainless steel part and a stainless steel part obtained after the treatment by means of the treatment method.

Abstract: Features for an aqueous reactor include a field generator. The field generator includes a series of parallel conductive plates including a series of intermediate neutral plates. The intermediate neutral plates are arranged in interleaved sets between an anode and a cathode. Other features of the aqueous reactor may include a sealed reaction vessel, fluid circulation manifold, electrical power modulator, vacuum port, and barrier membrane. Methods of using the field generator include immersion in an electrolyte solution and application of an external voltage and vacuum to generate hydrogen and oxygen gases. The reactor and related components can be arranged to produce gaseous fuel or liquid fuel. In one use, a mixture of a carbon based material and a liquid hydrocarbon is added. The preferred carbon based material is powdered coal.

Abstract: An electrochemical hydrogen compression apparatus and a method for the collection and compression of hydrogen. The apparatus includes a cathode having a surface that is modified with a Tafel inhibitor that inhibits the Tafel reaction at the cathode surface. The same cathode surface may also include a Volmer catalyst to enhance the Volmer reaction at the cathode surface. The apparatus and method can advantageously increase the pressure of collected hydrogen, and may be useful for supplying the hydrogen to energy producing devices, such as a fuel cell.

Abstract: Improved electrochemical production of hydrogen peroxide is provided with a surface-oxidized carbon catalyst. The carbon can be, for example, carbon black or carbon nanotubes. The oxidation of the carbon can be performed, for example, by heating the carbon in nitric acid, or by heating the carbon in a base. The resulting carbon catalyst can have a distinctive oxygen is peak in its X-ray photoelectron spectrum.

Abstract: A product container is provided. The product container includes a first product and an electrochemistry device configured to convert a portion of the first product into a second product, which is an unstable formulation.

Abstract: Disclosed are methods for the electrochemical oxidation of a C—H bond in a compound to give a C—O bond or C—S bond. The oxidation of methane to methanol is described, as well as an electrochemical cell for performing the reaction.

Abstract: A process for producing glycerol carbonate can include providing an electrolyte including CO2 and glycerol in an electrochemical reaction unit, and applying an electrochemical potential between an anode and a cathode immersed in the electrolyte to electrochemically transform the CO2 and glycerol into glycerol carbonate. Providing reduced viscosity and/or certain temperature conditions can advantageously enhance production. The CO2 can be supplied via a CO2-loaded stream obtained from an absorption reactor, or as a gas phase, into the electrochemical reaction unit. The resulting reaction mixture can be processed by solvent extraction of the glycerol carbonate, while the recovered glycerol can be recycled for reuse in electrochemical reactions. Systems including an electrochemical reaction unit, an extractor, an optional absorption reactor, an optional water removal unit, and an optional CO2 gas recycle assembly, is also described.

Abstract: An anti-explosion gas generator for health use is provided. The anti-explosion gas generator for health use includes an electrolysis device for electrolyzing water to produce a gas mixture of hydrogen and oxygen. The gas generator for health use further includes a gas mixing system coupled to the electrolysis device for receiving the gas mixture. The gas mixing system mixes the gas mixture with water vapor, an atomized medicine, a volatile essential oil or a combination thereof to produce a health gas. The health gas is provided for being inhaled by a user.