摘要:
The invention relates to an abrasive containing a slurry of the cerium oxide grains dispersed in water. The Cerium oxide grains are obtained by adding hydrogen peroxide to an aqueous dispersion of cerium carbonate. The Cerium oxide grains are obtained by oxidizing a precipitate, which is formed through addition of ammonium hydrogencarbonate to an aqueous solution of cerium nitrate, with hydrogen peroxide. The Cerium oxide grains are obtained by neutralizing or alkallfying an aqueous solution of cerium ammonium nitrate.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent in forming a protecting film and (5) water; and a method for polishing.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent in forming a protecting film and (5) water; and a method for polishing.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent in forming a protecting film and (5) water; and a method for polishing.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent in forming a protecting film and (5) water; and a method for polishing.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent informing a protecting film and (5) water; and a method for polishing.
摘要:
An abrasive liquid for a metal comprising (1) an oxidizing agent for a metal, (2) a dissolving agent for an oxidized metal, (3) a first protecting film-forming agent such as an amino acid or an azole which adsorbs physically on the surface of the metal and/or forms a chemical bond, to thereby form a protecting film, (4) a second protecting film-forming agent such as polyacrylic acid, polyamido acid or a salt thereof which assists the first protecting film-forming agent in forming a protecting film and (5) water; and a method for polishing.
摘要:
As new compounds are now provided 7,7,8,8,-tetramethyl-cis-diaza-bicyclo{4.2.0}octane-3,5,-dione derivatives which have an activity to induce the differentiation of tumor cells and are useful as antitumor agent, and which also have an antiviral activity against various viruses and are useful as antiviral agent. These new derivatives may be produced by a photo-addition reaction of a uracil compound with 2,3-dimethyl-2-butene.
摘要:
Disclosed is a semiconductor device and method for manufacturing the same, which is provided with a first wiring layer whose thickness within a contact hole is great in a lower portion of the contact hole and is small in an upper portion thereof. Since the first wiring layer at the lower portion of the contact hole is sufficiently thick, reaction between a second wiring layer formed on the first wiring layer and a substrate is effectively prevented. The first wiring layer is formed by bias sputtering in which a bias voltage is applied to the substrate.
摘要:
Descaling elements for cleaning cooling water tubes within a steam condenser are received within a water soaking vessel. A wire net is stretched within said vessel, and said vessel is charged with water until the water level reaches a predetermined limit line above said wire net. The presence of the wire net prevents the descaling elements from being floated up to the water surface. A considerably large space is formed between the water surface and the ceiling of the vessel. Said space communicates with an evacuating device for deaerating the interior of the vessel, and no air filter or air separator is required for said evacuating device.BACKGROUND OF THE INVENTIONThis invention relates to the heat exchanging tubes of a heat exchanger, and more particularly to a descaling system for cleaning the cooling water tubes of a steam condenser, and further in detail to a descaling system for removing substances deposited on the inner walls of the cooling water tubes of a steam condenser by continuously forcing a large number of descaling elements such as water-soaked sponge balls through said tubes.As above described, a descaling system is known which uses water-holding descaling elements for the purpose of cleaning the steam condenser tubes. For example, in the known descaling system a circulation passageway for passing descaling elements therethrough connects with the cooling water inlet pipe and outlet pipe of a steam condenser. In the course of said passageway a water-soaking vessel within which descaling elements are received and which is charged with cooling water is provided. Said vessel is provided with an evacuating device for evacuating the vessel interior up to a prescribed vacuum level. Said evacuating device is generally provided with plural deaeration valves and vacuum pump or air ejector and, in addition, provided with an air filter or air separator for removing water so as to prevent it from entering said pump or ejector.The above-mentioned descaling system has the drawbacks that all of the descaling elements can not be evenly, fully soaked with water because many of the descaling elements are floated up to the proximity of the water surface within the vessel; and a water separator or filter should be provided and the piping line should also be of water-resistant quality because when the vessel interior is deaerated by the evacuating device, water is also soaked into the piping line of said device, resulting in a complicated construction of the evacuating device and an increase in its manufacturing cost.SUMMARY OF THE INVENTIONThe general object of the invention is to provide an improved descaling system eliminating the drawbacks in the foregoing conventional descaling system.In the descaling system of the invention, a wire net is stretched within a water-soaking vessel having descaling elements received therein; said descaling elements are received below said wire net; said vessel is charged with water up to a predetermined limit line above the wire net; said wire net is in a state always immersed in water during the water soaking operation for the descaling elements; and a considerably large volume of space is provided in the upper part of the vessel interior and the water within the vessel has a free surface.Accordingly, in the descaling system of the invention, when the water-soaking vessel is deaerated by an evacuating device associated with said vessel, there is a reduced possibility of water being entered into the piping line of said device because of the presence of a considerably large volume of space. As the result, the necessity of providing a water filter or water separator within said device is reduced, offering the advantage of attaining the manufacturing cost reduction of the evacuating device.Since the descaling elements are prevented from being floated on the water surface by the wire net, they are fully immersed in the water, offering the advantage of reliably enabling the water soaking.Accordingly, an object of the invention is to provide a descaling system low in manufacturing cost.Another object of the invention is to provide a descaling system enabling the water soaking operation for the descaling elements to be reliably carried out, thereby attaining a good descaling effect.A still another object of the invention is to provide a descaling system enabling the water soaking operation for the descaling elements to be carried out for a short time with high efficiency.