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3425results about How to "Avoid deposition" patented technology

Process of manufacturing Trench gate semiconductor device having gate oxide layer with multiple thicknesses

The a trench semiconductor device such as a power MOSFET the high electric field at the corner of the trench is diminished by increasing the thickness of the gate oxide layer at the bottom of the trench. Several processes for manufacturing such devices are described. In one group of processes a directional deposition of silicon oxide is performed after the trench has been etched, yielding a thick oxide layer at the bottom of the trench. Any oxide which deposits on the walls of the trench is removed before a thin gate oxide layer is grown on the walls. The trench is then filled with polysilicon in or more stages. In a variation of the process a small amount of photoresist is deposited on the oxide at the bottom of the trench before the walls of the trench are etched. Alternatively, polysilicon can be deposited in the trench and etched back until only a portion remains at the bottom of the trench. The polysilicon is then oxidized and the trench is refilled with polysilicon. The processes can be combined, with a directional deposition of oxide being followed by a filling and oxidation of polysilicon. A process of forming a "keyhole" shaped gate electrode includes depositing polysilicon at the bottom of the trench, oxidizing the top surface of the polysilicon, etching the oxidized polysilicon, and filling the trench with polysilicon.
Owner:ADVANCED ANALOGIC TECHNOLOGIES INCORPORATED

Controlled downhole chemical injection

A petroleum well having a well casing, a production tubing, a source of time-varying current, a downhole chemical injection device, and a downhole induction choke. The casing extends within a wellbore of the well. The tubing extends within the casing. The current source is located at the surface. The current source is electrically connected to, and adapted to output a time-varying current into, the tubing and/or the casing, which act as electrical conductors for providing downhole power and/or communications. The injection device having a communications and control module, a chemical container, and an electrically controllable chemical injector. The communications and control module is electrically connected to the tubing and/or the casing. The chemical injector is electrically connected to the communications and control module, and is in fluid communication with the chemical container. The downhole induction choke is located about a portion of the tubing and/or the casing. The chemical injector is electrically connected to the communications and control module, and is in fluid communication with the chemical container. The downhole induction choke is located about a portion of the tubing and/or the casing. The induction choke is adapted to route part of the electrical current through the communications and control module by creating a voltage potential between one side of the induction choke and another side of the induction choke. The communications and control module is electrically connected across the voltage potential. Also, a method is provided for controllably injecting a chemical into the well downhole, which may be used to: improve lift efficiency with a foaming agent, prevent deposition of solids with a paraffin solvent, improve a flow characteristic of the flow stream with a surfactant, prevent corrosion with a corrosion inhibitor, and/or prevent scaling with scale preventers.
Owner:SHELL OIL CO

Exhaust aftertreatment system using urea water

An exhaust aftertreatment system comprises an injector for injecting urea water into an exhaust duct, and a denitration catalyst disposed downstream of the injector with respect to a flow of exhaust gas. The exhaust aftertreatment system reduces nitrogen oxides in the exhaust gas by the denitration catalyst while using ammonia produced from the urea water injected from the injector. The urea water is injected along a direction of the flow of the exhaust gas within the exhaust duct, and a porous plate is disposed in multiple stages in a space of the exhaust duct such that droplets of the injected urea water impinge against the porous plate before reaching a wall surface of the exhaust duct. A surface of the porous plate subjected to the impingement of the droplets is arranged to face downstream with respect to the flow of the exhaust gas. Deposition of the urea water is prevented by causing film boiling when the droplets impinge against the porous plate, and the urea water reflected by the porous plate is uniformly dispersed into the exhaust gas. Thus, the urea water is uniformly dispersed into the exhaust gas without increasing a pressure loss of the exhaust gas. The urea water is prevented from depositing on the wall surface and producing a precipitate in the form of a solid.
Owner:HITACHI HIGH-TECH CORP +2

Color mixer and reversing valve device thereof

ActiveCN103968106ASolve the phenomenon of color paste dryingSolve the problem of color paste depositionPlug valvesTransportation and packagingInjection pumpPhysics
The invention discloses a reversing valve device. A first opening on a valve body is used for being communicated with a colorant container while a second opening on the same is used for being communicated with an injection pump, a valve core is arranged in an internal valve cavity of the valve body in a pivoted manner, an internal passage and a first colorant injection hole are arranged on the valve core, the internal passage is communicated with the second opening of the valve body, one end of the first colorant injection hole is communicated with the internal passage while the other end of the same is arranged on the peripheral surface of the valve core, a third opening on the valve body is formed on the inner wall of the internal valve cavity, a first passage is communicated with the first opening and the third opening, a fourth opening is formed on the lower end face of the valve body and communicated with the internal valve cavity, the first colorant injection hole can switch working positions along with rotating of the valve core, and the first colorant injection hole is exposed out of the fourth opening when being at a first colorant injection working position and communicated with the third opening when being at a non-colorant-injection position. By structural optimization, the phenomenon that colorant appears at a colorant outlet can be completely avoided. On the basis, the invention further provides a color mixer with the reversing valve device.
Owner:ZHENGZHOU SANHUA TECH & IND
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