Abstract: A small cooling fan includes a rotating fan body with a vane in a flat fan housing, and an air channel for backflow prevention. The air channel is provided outside of the vicinity of the tip of the vane of the rotating fan body, extends to an air outlet, and has an inner height larger than that of a fan chamber. This structure can prevent the backflow of the wind at the air outlet and reduce the loss of the static pressure, thereby increasing the airflow quantity in spite of the small size.

Abstract: A lead-free solder paste comprises an Sn—Zn based lead-free solder powder mixed with a flux. The flux contains at least one aromatic hydroxycarboxylic acid selected from the group consisting of aromatic carboxylic acids having one hydroxyl group in a meta position (such as 3-hydroxy-2-methylbenzoic acid) and aromatic carboxylic acids having at least two hydroxyl groups (such as dihydroxynaphthoic acid or dihydroxybenzoic acid) in an amount of 0.1-10.0 mass %. The flux may further include 0.5-20 mass % of an aliphatic hydroxy carboxylic acid (such as hydroxyoleic acid).

Abstract: A solder paste comprising a powder of a Zn-containing Sn-based, lead-free solder mixed with an activator-containing rosin-based flux to which 0.5-10.0 wt % of isocyanuric acid or a haloalkyl ester thereof is added can prevent the formation of solder balls and voids during reflow soldering and exhibit good solderability. A solder paste comprising a powder of an Ag- or Zn-containing Sn-based, lead-free solder mixed with an activator-containing rosin-based flux to which 0.01-10.0 wt % of a salicylamide compound also does not exhibit a change in viscosity and exhibits good solderability.

Abstract: A lead-free solder paste comprises an Sn—Zn based lead-free solder powder mixed with a flux. The flux contains at least one aromatic hydroxycarboxylic acid selected from the group consisting of aromatic carboxylic acids having one hydroxyl group in a meta position (such as 3-hydroxy-2-methylbenzoic acid) and aromatic carboxylic acids having at least two hydroxyl groups (such as dihydroxynaphthoic acid or dihydroxybenzoic acid) in an amount of 0.1-10.0 mass %. The flux may further include 0.5-20 mass % of an aliphatic hydroxy carboxylic acid (such as hydroxyoleic acid).

Abstract: A small cooling fan includes a rotating fan body with a vane in a flat fan housing, and an air channel for backflow prevention. The air channel is provided outside of the vicinity of the tip of the vane of the rotating fan body, extends to an air outlet, and has an inner height larger than that of a fan chamber. This structure can prevent the backflow of the wind at the air outlet and reduce the loss of the static pressure, thereby increasing the airflow quantity in spite of the small size.

Abstract: A solder paste having a powder of a Zn-containing solder alloy such as an Sn—Zn based alloy in admixture with a soldering flux such as a rosin flux is improved by adding from 0.1% to 5.0% by weight of a glycidyl ether compound such as alkyl, alkenyl, or aryl glycidyl ether. The improved solder paste has increased resistance to aging and to concomitant deterioration in solderability caused by reaction of Zn in the solder alloy with ingredients in the flux and has a substantially extended shelf life.

Abstract: An organic acid salt is deposited on the surface of a solder powder containing Sn and Zn. Alternatively, 0.5 to 10 wt. % of a nonionic surfactant is added to a flux. By a method comprising such a procedure, provided are a lead-free solder powder and solder paste having good soldering characteristics wherein the reaction of an activating component with an alloy component in a flux is suppressed.

Abstract: A solder paste having a powder of a Zn-containing solder alloy such as an Sn—Zn based alloy in admixture with a soldering flux such as a rosin flux is improved by adding from 0.1% to 5.0% by weight of a glycidyl ether compound such as alkyl, alkenyl, or aryl glycidyl ether. The improved solder paste has increased resistance to aging and to concomitant deterioration in solderability caused by reaction of Zn in the solder alloy with ingredients in the flux and has a substantially extended shelf life.

Abstract: In order to prevent aging of an Sn--Zn system alloy solder paste, 0.5-5% by weight of a compound obtained by adding an ethylene oxide to cyclohexylamine, preferably together with 0.5-5% by weight of a polyoxyethylene alkylamine is added to a flux of said solder paste.