A silica membrane filter 10 includes an ultrafiltration membrane 15, which is disposed on a support body 14 and which contains an element 14 as a primary component, and a silica membrane 18 which is disposed on the ultrafiltration membrane 15 and which has an aryl group. The ultrafiltration membrane 15 has a structure infiltrated by Si of the silica membrane 18, the atomic ratio A (=Si/M) of Si to the element M in a membrane-side region 16, which is a region corresponding to 25% of the ultrafiltration membrane 15 from the silica membrane 18, satisfies 0.01≦A≦0.5, and the ratio A/B of the atomic ratio A to the atomic ratio B (=Si/M) in a base-material-side region 17, which is a region corresponding to 25% from the support body 14, is within the range of 1.1 or more.

Methods for forming and controlling morphology cracks in silicon dioxide (SiO.sub.2) film comprising: preparing SiO.sub.2precursor solution comprising solvent, precursor of SiO.sub.2, precursor of metal oxide nanocrystals, water, and acid; coating the solution onto substrate; drying the solution atop the substrate at a temperature between about 20° C. to 100° C. between 1 minute to 24 hours to form SiO.sub.2 film having uniformly dispersed metal oxide nanocrystals, wherein shorter drying times yield substantially spherical shaped metal oxide nanocrystals and longer drying times yield rod and disc shaped metal oxide nanocrystals; and thermally treating the SiO.sub.2 film between about 60° C. to 500° C. between 1 minute to 24 hours to form cracked mesh SiO.sub.2 film, wherein two cracks initiate from rod shaped metal oxide nanocrystals, three to four cracks initiate from spherical shaped metal oxide nanocrystals, and four or more cracks initiate from disc shaped metal oxide nanocrystals. Other embodiments are described and claimed.

Methods for forming and controlling morphology cracks in silicon dioxide (SiO.sub.2) film comprising: preparing SiO.sub.2precursor solution comprising solvent, precursor of SiO.sub.2, precursor of metal oxide nanocrystals, water, and acid; coating the solution onto substrate; drying the solution atop the substrate at a temperature between about 20° C. to 100° C. between 1 minute to 24 hours to form SiO.sub.2 film having uniformly dispersed metal oxide nanocrystals, wherein shorter drying times yield substantially spherical shaped metal oxide nanocrystals and longer drying times yield rod and disc shaped metal oxide nanocrystals; and thermally treating the SiO.sub.2 film between about 60° C. to 500° C. between 1 minute to 24 hours to form cracked mesh SiO.sub.2 film, wherein two cracks initiate from rod shaped metal oxide nanocrystals, three to four cracks initiate from spherical shaped metal oxide nanocrystals, and four or more cracks initiate from disc shaped metal oxide nanocrystals. Other embodiments are described and claimed.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica. Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica. Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein

the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein

the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

A silica-containing resin composition, characterized by containing a resin and silica particles in an amount of 5 to 300 parts by mass, with respect to 100 parts by mass of the resin, wherein the silica particles satisfy the following requirements (a) to (c): (a) the silica particles have a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m.sup.2/g; (b) the silica particles have a percent moisture absorption of 5.0 mass % or less at a relative humidity of 50%; and (c) the silica particles contain substantially no metallic impurity or halogen.

A silica-containing resin composition, characterized by containing a resin and silica particles in an amount of 5 to 300 parts by mass, with respect to 100 parts by mass of the resin, wherein the silica particles satisfy the following requirements (a) to (c): (a) the silica particles have a specific surface area, as determined through a nitrogen absorption method, of 20 to 500 m.sup.2/g; (b) the silica particles have a percent moisture absorption of 5.0 mass % or less at a relative humidity of 50%; and (c) the silica particles contain substantially no metallic impurity or halogen.

The present invention is to provide a toner for developing electrostatic images, which has an excellent balance between low-temperature fixability and heat-resistant shelf stability, which has good toner conveyance amount stability and printing durability, and which has less occurrence of fog in a high temperature and high humidity environment. Disclosed is a toner for developing electrostatic images, comprising colored resin particles containing a binder resin and a colorant, and an external additive, wherein the toner comprises, as the external additive, fine silica particles in an amount of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the colored resin particles, the fine silica particles having a hydrophobicity of 15 to 49% that is determined after a high-temperature and high-humidity incubation.