An object of the present invention is to provide a composition for forming an undercoat layer capable of forming an undercoat layer that does not easily peel off from the substrate, an undercoat layer formed by the composition, as well as an exhaust gas purification catalyst and an exhaust gas purification apparatus each including the undercoat layer, and, to achieve the object, the present invention provides a composition for forming an undercoat layer, the composition containing tin oxide microparticles and tin oxide nanoparticles, wherein a content of the tin oxide nanoparticles is 8% by mass or more and 30% by mass or less, with respect to a total content of the tin oxide microparticles and the tin oxide nanoparticles, an undercoat layer formed by the composition, as well as an exhaust gas purification catalyst and an exhaust gas purification apparatus each including the undercoat layer.

A process for preparing C.sub.2 to C.sub.5 olefins includes introducing a feed stream comprising hydrogen and at least one carbon-containing component selected from the group consisting of CO, CO.sub.2, and mixtures thereof into a reaction zone. The feed stream is contacted with a hybrid catalyst in the reaction zone, and a product stream is formed that exits the reaction zone and includes C.sub.2 to C.sub.5 olefins. The hybrid catalyst includes a methanol synthesis component and a solid microporous acid component that is selected from molecular sieves having 8-MR access and having a framework type selected from the group consisting of CHA, AEI, AFX, ERI, LTA, UFI, RTH, and combinations thereof. The methanol synthesis component comprises a metal oxide support and a metal catalyst. The metal oxide support includes titania, zirconia, hafnia or mixtures thereof, and the metal catalyst includes zinc.

A preparation method for a highly chlorine- and water-resistant catalyst is provided. A mixture of at least one of SnO.sub.2, GeO.sub.2, and MoO.sub.2 with CeO.sub.2 is used as a catalyst support, face-centered cubic ruthenium oxide is used as an active component, and the catalyst with excellent chlorine- and water-resistance is prepared through selective adsorption regulation, which can realize safe and efficient purification of chlorine-containing organic waste gas at temperatures below 250° C.

A preparation method for a highly chlorine- and water-resistant catalyst is provided. A mixture of at least one of SnO.sub.2, GeO.sub.2, and MoO.sub.2 with CeO.sub.2 is used as a catalyst support, face-centered cubic ruthenium oxide is used as an active component, and the catalyst with excellent chlorine- and water-resistance is prepared through selective adsorption regulation, which can realize safe and efficient purification of chlorine-containing organic waste gas at temperatures below 250° C.

The present invention is related to a curable composition for dental impression comprising: a curable base composition and a surfactant system comprising a first surfactant, which is at least one compound having formula (I) and a fluorotelomer having formula (II), which works synergistically with the fluorotelomer so as to permit the composition to surprisingly have a lower contact angle; these results are reached with relatively low concentrations of biodegradable surfactants.

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The present invention is related to a curable composition for dental impression comprising: a curable base composition and a surfactant system comprising a first surfactant, which is at least one compound having formula (I) and a fluorotelomer having formula (II), which works synergistically with the fluorotelomer so as to permit the composition to surprisingly have a lower contact angle; these results are reached with relatively low concentrations of biodegradable surfactants.

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Embodiments of the present invention include a filter element for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst. The embodiments of the present invention also includes a system for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst; and a method using the system.

Embodiments of the present invention include a filter element for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst. The embodiments of the present invention also includes a system for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst; and a method using the system.

Provided are a composite structure, in which metal nanoparticle-perovskite oxide is bound to metal oxide supports (i.e., sensing materials), and a preparation method thereof. The composite structure has improved durability, in which metal nanoparticles uniform in size are evenly distributed on the surface of perovskite oxide. Provided is also a high-performance gas sensor having excellent target gas detection performances by including the composite structure.

Provided are a composite structure, in which metal nanoparticle-perovskite oxide is bound to metal oxide supports (i.e., sensing materials), and a preparation method thereof. The composite structure has improved durability, in which metal nanoparticles uniform in size are evenly distributed on the surface of perovskite oxide. Provided is also a high-performance gas sensor having excellent target gas detection performances by including the composite structure.