Abstract: Silica particles having a thiol group on a surface thereof, and satisfying the following conditions (a) to (c): (a) a particle diameter is 20 to 1,000 nm; (b) a density of the thiol group on the surface of the silica particles is 0.002 to 0.2 piece/nm2; and (c) a ratio (B/A) in terms of an amount B (piece/particle) of the thiol group existing on the surface of the silica particles to an amount A of sulfur elements in the silica particles (the number of sulfur elements derived from thiol per silica particle) is 0.10 to 0.60.

Abstract: A method of producing a labeled antibody, including the steps of: a) allowing silica nanoparticles containing a functional molecule and having a thiol group on a surface thereof, and a linker molecule containing a maleimido group and an amino group, to coexist in a solvent to form a thioether bond between the thiol group and the maleimido group, thereby obtaining functional molecule-containing silica nanoparticles on which the linker molecule is bonded; and b) allowing the functional molecule-containing silica nanoparticles on which the linker molecule is bonded, carbodiimide and an antibody to coexist in an aqueous solvent to form an amide bond between the amino group of the linker molecule and a carboxyl group of the antibody.

Abstract: Silica particles having a thiol group on a surface thereof, and satisfying the following conditions (a) to (c): (a) a particle diameter is 20 to 1,000 nm; (b) a density of the thiol group on the surface of the silica particles is 0.002 to 0.2 piece/nm2; and (c) a ratio (B/A) in terms of an amount B (piece/particle) of the thiol group existing on the surface of the silica particles to an amount A of sulfur elements in the silica particles (the number of sulfur elements derived from thiol per silica particle) is 0.10 to 0.60.

Abstract: A method of producing a labeled antibody, including the steps of: a) allowing silica nanoparticles containing a functional molecule and having a thiol group on a surface thereof, and a linker molecule containing a maleimido group and an amino group, to coexist in a solvent to form a thioether bond between the thiol group and the maleimido group, thereby obtaining functional molecule-containing silica nanoparticles on which the linker molecule is bonded; and b) allowing the functional molecule-containing silica nanoparticles on which the linker molecule is bonded, carbodiimide and an antibody to coexist in an aqueous solvent to form an amide bond between the amino group of the linker molecule and a carboxyl group of the antibody.

Abstract: A metal nanonetwork includes metal nanostructures that are joined by metallic bond. The joined part between the metal nanostructures includes a fillet part. In the joined part between the metal nanostructures, the distance between the central axis of one metal nanostructure and the central axis of another metal nanostructure is smaller than the sum of the radii of both metal nanostructures. The metal nanostructure is a metal nanowire. A first method for producing the metal nanonetwork includes a process of forming an oxide film on the outermost surface of the metal nanostructure, and a process of reducing the oxide film at the joined parts of a plurality of the metal nanostructures to thereby join the metal nanostructures.

Abstract: In a fine particle dispersion, a fine particle (P) is dispersed in a mixed organic solvent. The fine particle (P) is formed of one type or not less than two types of a metal, an alloy, and/or a metallic compound, and has a mean particle diameter between 1 nm and 150 nm for primary particles thereof. Further, the fine particle (P) has a surface at least a part thereof coated with a polymer dispersing agent (D).

Abstract: In a fine particle dispersion, a fine particle (P) is dispersed in a mixed organic solvent. The fine particle (P) is formed of one type or not less than two types of a metal, an alloy, and/or a metallic compound, and has a mean particle diameter between 1 nm and 150 nm for primary particles thereof. Further, the fine particle (P) has a surface at least a part thereof coated with a polymer dispersing agent (D).

Abstract: A method for producing a fine particle dispersion includes the steps of reducing a metal ion to form a fine particle dispersion aqueous solution; adding an aggregation accelerator into the fine particle dispersion aqueous solution so that agglomerated or precipitated fine particles are separated to obtain fine particles; and re-dispersing the fine particles into an organic solvent containing an organic solvent having an amide group, a low boiling point organic solvent having a boiling point between 20° C. and 100° C. at a normal pressure, and an organic solvent having a boiling point higher than 100° C. at a normal pressure and containing an alcohol and/or a polyhydric alcohol.

Abstract: Disclosed is a fine particle dispersion which is superior in dispersibility and storage stability. Specifically disclosed is a fine particle dispersion in which a fine particle (P) comprised of one type or not less than two types of a metal, an alloy, and/or a metallic compound, having a mean particle diameter of between 1 nm and 150 nm for primary particles thereof, with being coated at least a part of a surface thereof with a polymer dispersing agent (D), is dispersed in a mixed organic solvent. This fine particle dispersion is characterized in that a weight ratio of (D/P) between the polymer dispersing agent (D) coating the surface of the fine particle (P) and the fine particles (P) in the dispersion is between 0.001 and 10, and the mixed organic solvent is one of: (i) a mixed organic solvent which contains an organic solvent (A) as between 50% and 95% by volume having an amide group, and a low boiling point organic solvent (B) as between 5% and 50% by volume having a boiling point of between 20° C.

Abstract: Disclosed is a method for producing a fine particle dispersion such as a dispersion of metal fine particles which is superior in dispersibility and storage stability. Specifically disclosed is a method for producing a fine particle dispersion wherein fine particles of a metal or the like, having a mean particle diameter of between 1 nm and 150 nm for primary particles, are dispersed in an organic solvent.

Abstract: An EA-DFB module including a DFB laser diode and an EA modulator formed on an InP first-conductivity-type substrate has a mesa stripe, a current blocking structure formed on both side surfaces of the mesa strip and a second InP cladding layer formed on top of the mesa stripe and the current blocking structure. The current blocking structure includes a Fe-doped semi-insulating film, a first conductivity-type buried layer and a carrier-depleted layer. The carrier-depleted layer reduces the parasitic capacitance at the boundary between the first-conductivity-type buried layer and the second InP cladding layer.

Abstract: An EA-DFB module including a DFB laser diode and an EA modulator formed on an InP first-conductivity-type substrate has a mesa stripe, a current blocking structure formed on both side surfaces of the mesa strip and a second InP cladding layer formed on top of the mesa stripe and the current blocking structure. The current blocking structure includes a Fe-doped semi-insulating film, a first conductivity-type buried layer and a carrier-depleted layer. The carrier-depleted layer reduces the parasitic capacitance at the boundary between the first-conductivity-type buried layer and the second InP cladding layer.

Abstract: Disclosed is a process of producing a semiconductor layer structure which emits lights with a plurality of luminescence wavelengths from the same quantum well structure. The layer structure has a layer structure which has the quantum well structure located between a lower light-confinement layer and an upper light-confinement layer. At least a part of the quantum well structure is an area which has a shorter luminescence wavelength than those of the other portions. This area is produced by stacking a lower cladding layer, the lower light-confinement layer, the quantum well structure, the upper light-confinement layer and a first semiconductor layer having a first conductivity type on a semiconductor substrate by epitaxial growth and further stacking a second semiconductor layer having the opposite conductivity type to that of the first semiconductor layer on the entire surface or a partial surface of the first semiconductor layer. This second semiconductor layer may be removed after the formation.

Abstract: A semiconductor laser has a multiple-quantum well (MQW) structure overlying a first III-V compound semiconductor. The MQW includes a plurality of layer combinations including a strained well layer and a strained barrier layer, which are formed in a cyclic order. An ultra-thin intermediate film made of the first III-V compound semiconductor and having a thickness corresponding to from monoatomic layer to ten atomic layer is interposed between each strained well layer and each strained barrier layer. The intermediate film functions for preventing formation of mixed crystal formed between the well layer and the barrier layer, thereby improving current density threshold and other characteristics of the semiconductor laser.

Abstract: The present invention gives rise to a 1.3 .mu.m tensile-strained quantum well laser having a quantum well active layer which can be structurally specified as In.sub.1-x Ga.sub.x As.sub.y P.sub.1-y with X between 0.42 and 0.55 and Y between 0.8 and 0.75. The InGaAsP active layer needs to have a tensile stress between 1.0 and 1.5% and can be fabricated without any substantial phase-separation between InP and GaAs. The 1.3 .mu.m tensile-strained quantum well laser is equipped with a remarkably meager threshold current density of less than 0.2 kA/cm.sup.2. The preferable tensile strain ranges between from 1.2 to 1.4% or thereabout.