Abstract:
A process for making cerium dioxide nanoparticles containing at least one transition metal (M) utilizes a suspension of cerium hydroxide nanoparticles prepared by mechanical shearing of an aqueous mixture containing an oxidant in an amount effective to enable oxidation of cerous ion to ceric ion, thereby forming a product stream that contains transition metal-containing cerium dioxide nanoparticles, Ce1-xMxO2, wherein “x” has a value from about 0.3 to about 0.8. The nanoparticles thus obtained have a cubic fluorite structure, a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm, and a geometric diameter of less than about 4 nm. The transition metal-containing crystalline cerium dioxide nanoparticles can be used to prepare a dispersion of the particles in a nonpolar medium.
Abstract:
A process for making cerium dioxide nanoparticles containing at least one transition metal (M) utilizes a suspension of cerium hydroxide nanoparticles prepared by mechanical shearing of an aqueous mixture containing an oxidant in an amount effective to enable oxidation of cerous ion to ceric ion, thereby forming a product stream that contains transition metal-containing cerium dioxide nanoparticles, Ce1-xMxO2, wherein “x” has a value from about 0.3 to about 0.8. The nanoparticles thus obtained have a cubic fluorite structure, a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm, and a geometric diameter of less than about 4 nm. The transition metal-containing crystalline cerium dioxide nanoparticles can be used to prepare a dispersion of the particles in a nonpolar medium.
Abstract:
Cylindrical optical components of quartz glass are known, which have an inner zone made of an inner zone glass, which extends in the direction of the longitudinal axis and is surrounded by a jacket zone made of a jacket zone glass, the average pt wall thickness thereof varying at least over a part of its length in the direction of the longitudinal axis of the component. The aim of the invention is to provide a method that allows a simple and cost-effective production of such an optical component from quartz glass. A method is proposed according to the invention, comprising the following method steps: (a) providing a first parison made of an inner zone glass, which has a first contact surface on the end face, said contact surface having a conical external contour; (b) providing a second parison from the jacket zone glass; (c) embedding the contact surface with a conical external contour into the jacket zone glass and welding the contact surface to the jacket zone glass, thereby forming a composite parison which has a cone-shaped inner zone area of inner zone glass in a contact area, said inner zone area being surrounded by a jacket zone having the shape of an inner cone; and (d) elongation of the composite parison to form the optical component or a preproduct of the component.
Abstract:
A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.
Abstract:
The invention relates to a method allowing cost-effective production of doped quartz glass, particularly laser-active quartz glass, that is improved with regard to the homogeneity of the doping material distribution, in that a suspension is provided comprising SiO2 particles and an initial compound for at least one doping material in an aqueous fluid, the fluid being removed under formation of a doped intermediate product comprising particles of the doping material or particles of the precursor substance or the doping material, and the doped quartz glass is formed by sintering the doped intermediate product, wherein at least part of the particles of the doping material or the particles of the precursor substance of the same is generated in the suspension as a precipitate of a pH-value-controlled precipitation reaction of the initial compound.
Abstract:
A process for replacing the continuous phase of a nanoparticle dispersion with a less polar phase, includes filtering the dispersion through a semi-permeable membrane filter to remove the continuous phase, and introducing a less polar phase.
Abstract:
The aim of the invention is to improve a generally known method for producing quartz glass doped with fluorine, wherein SiO2 particles are formed in the presence of fluorine by means of a plasma deposition process, deposited in layers on an outer envelope of a cylindrical quartz glass substrate body rotating about its longitudinal axis, and vitrified to form a layer of quartz glass with a fluorine content of at least 1.5 wt. %, in such a way that a quartz glass semifinished product with a high fluorine content, characterised by a high basic transmission in the UV wavelength range, is obtained. To this end, the substrate body has at least one reservoir layer of quartz glass at least in the region of the outer envelope thereof, having a minimum hydroxyl group content of 200 wt. ppm and/or a minimum hydrogen content of 1×1017 molecules/cm3, and the substrate body is either fully or partially removed following the deposition of the quartz glass layer doped with fluorine.
Abstract translation:本发明的目的是改进用于生产掺杂有氟的石英玻璃的通常已知的方法,其中通过等离子体沉积工艺在氟存在下形成SiO 2颗粒,其沉积在圆柱形石英玻璃的外包层上 衬底体围绕其纵向轴线旋转,并且玻璃化以形成氟含量为至少1.5重量%的石英玻璃层。 以这样的方式获得具有高氟含量的石英玻璃半成品,其特征在于在UV波长范围内具有高的基本透射率。 为此,衬底主体至少在其外壳的区域中具有至少一个石英玻璃储存层,其最小羟基含量为200重量%。 ppm和/或1×1017分子/ cm 3的最小氢含量,并且在掺杂了氟的石英玻璃层沉积之后,基板主体被完全或部分地去除。
Abstract:
Cylindrical optical components of quartz glass are known, which have an inner zone made of an inner zone glass, which extends in the direction of the longitudinal axis and is surrounded by a jacket zone made of a jacket zone glass, the average wall thickness thereof varying at least over a part of its length in the direction of the longitudinal axis of the component. The aim of the invention is to provide a method that allows a simple and cost-effective production of such an optical component from quartz glass. A method is proposed according to the invention, comprising the following method steps: (a) providing a first parison made of an inner zone glass, which has a first contact surface on the end face, said contact surface having a conical external contour; (b) providing a second parison from the jacket zone glass; (c) embedding the contact surface with a conical external contour into the jacket zone glass and welding the contact surface to the jacket zone glass, thereby forming a composite parison which has a cone-shaped inner zone area of inner zone glass in a contact area, said inner zone area being surrounded by a jacket zone area having the shape of an inner cone; and (d) elongation of the composite parison to form the optical component or a preproduct of the component.
Abstract:
A process for replacing the continuous phase of a nanoparticle dispersion with a less polar phase, includes filtering the dispersion through a semi-permeable membrane filter to remove the continuous phase, and introducing a less polar phase.
Abstract:
A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.