Abstract: An object of the present invention is to efficiently produce ultrafine particles having such a small diameter as 50 nm or less, a narrow range of size distribution, and a non-oxidation surface. According to the present invention, the metallic ultrafine particles are produced by dropping a raw metallic powder onto a controllably heated evaporating surface in a decompressed inert gas; instantly evaporating the raw metallic powder to form the ultrafine particle; and condensing and depositing the ultrafine particle on a trapping surface arranged above the evaporating surface. The raw metallic powder is any one of a single metal, an alloy and an intermetallic compound, preferably has an average particle diameter controlled to 500 ?m or smaller so that the powder can be instantly evaporated, and is preferably supplied by a minute amount.

Abstract: An object of the present invention is to efficiently produce ultrafine particles having such a small diameter as 50 nm or less, a narrow range of size distribution, and a non-oxidation surface. According to the present invention, the metallic ultrafine particles are produced by dropping a raw metallic powder onto a controllably heated evaporating surface in a decompressed inert gas; instantly evaporating the raw metallic powder to form the ultrafine particle; and condensing and depositing the ultrafine particle on a trapping surface arranged above the evaporating surface. The raw metallic powder is any one of a single metal, an alloy and an intermetallic compound, preferably has an average particle diameter controlled to 500 ?m or smaller so that the powder can be instantly evaporated, and is preferably supplied by a minute amount.

Abstract: Method and apparatus for sensing liquid level of the invention includes a plurality of thermocouple elements that are formed by connecting two kind of thermocouple wires alternately in series into a plurality of thermometric contacts. The two kind of thermocouple wires have different thermoelectric powers SA and SB and have a variety of predetermined lengths. The invention can sense with high reliability a liquid level of a sensed liquid by changing electromotive forces from these thermocouple elements into binary signals by using fewer thermocouple elements than the conventional apparatus. The invention also includes thermocouple elements for parity check to self-diagnose the sensed result to inspect easily and securely errors in operation due to disconnections in the thermocouple elements or external noises.