摘要:
An abrasive grain including a porous particle material in which a large number of secondary particles contain gaps between primary particles bonded to each other. The secondary particles are produced by growing primary particles into secondary particles, which are formed by cohesion of a large number of primary particles, via a heat treatment at a temperature sufficient to form necks at bonding points between the primary particles.
摘要:
An abrasive grain including a porous particle material in which a large number of secondary particles contain gaps between primary particles bonded to each other. The secondary particles are produced by growing primary particles into secondary particles, which are formed by cohesion of a large number of primary particles, via a heat treatment at a temperature sufficient to form necks at bonding points between the primary particles.
摘要:
An abrasive grain including a porous particle material in which a large number of fine particles for cutting edges form gaps partly among them and bond loosely each other. The particles for the cutting edges are produced by growing primary particles in secondary particles, which are formed by cohesion of a large number of primary particles, with a heat treatment at a temperature of forming necks at bonding points among the primary particles.
摘要:
A processing tool is used to carry out a fixed-abrasive grinding process on a surface of a silicon work-piece. The processing tool includes abrasive grains made up silica grains. A primary average grain size of the silica grains is desirably 0.8 nm to 10 μm.
摘要:
An abrasive wire provides an efficient cutting operation with high accuracy and a longer service life. Abrasive grains are provided around a core wire. The abrasive grains are bonded to the core wire by a light curing resin or an electron beam curing resin which can be cured within a few seconds. Accordingly, the curing operation can be performed while the core wire is moved in the direction of the longitudinal axis of the core wire. Thus, a long abrasive wire can be fabricated at reduced time and cost.
摘要:
The present invention provides a hydrogen production method capable of producing hydrogen with good efficiency while solving problems such as separation, lower-temperature reaction and heat supply in production of hydrogen by dehydrogenation reaction of raw material oil. Within a reaction tube of a double-tube structure comprising an inner tube composed of a hydrogen separating membrane, a metallic outer tube having a plurality of internal fins, and a metal oxide layer and further a catalyst supported on the fins, hydrocarbon having cyclohexane ring is dehydrogenated to produce hydrogen and aromatic hydrocarbon, and selective membrane separating operation of hydrogen is performed within the reaction system while conducting the dehydrogenation to remove mainly the hydrogen on a permeating side and obtain mainly the aromatic hydrocarbon on a non-permeating side. The other method comprises absorbing at least part of the resulting hydrogen flow to a hydrogen absorbing (storing) alloy to make the pressure on the hydrogen permeating side of the hydrogen separating membrane lower than that on the non-permeating side.
摘要:
There is provided a catalyst that is highly resistant to sulfur and nitrogen compounds and active for hydrogenation and shows a low hydrocracking rate and a long service life as well as a method of converting aromatic hydrocarbons in hydrocarbon oil containing sulfur and nitrogen compounds into saturated hydrocarbons by using such a catalyst. A method of hydrogenating aromatic hydrocarbons in hydrocarbon oil containing 80 wt % or more of a fraction having a boiling point of 170 to 390° C. and said aromatic hydrocarbons is characterized in that the hydrocarbon oil is brought into contact with hydrogen in the presence of a catalyst containing clay minerals having principal ingredients of Si and Mg as carrier and at least one of the VIII-group metals of periodic table as active metal.
摘要:
A method for converting benzene and aromatic hydrocarbon compounds having 9 or more carbon atoms contained in a material oil having a boiling point of 30˜210° C. into toluene and aromatic hydrocarbon compounds having 8 carbon atoms in the presence of hydrogen and the said catalyst. The catalyst can be obtained by carrying at least one metal or metal compound selected from Group VIII and Group VIA of the Periodic Table on a carrier containing zeolites in which maximum diameter among diameters of its micropores is 0.6-1.0 nm and a ratio of SiO2/Al2O3 is 50 or more.
摘要:
An electrolytic in-process dressing method, an electrolytic in-process dressing grinding apparatus, and an electrolytic in-process dressing grindstone, for grinding workpiece as the grindstone is being subjected to electrolytic in-process dressing, are provided, in which the grindstone is made of abrasive grains and a binding material which is capable of forming a uniform and fine passive layer at the grinding surface thereof and also capable of preventing excessive elusion of the binding material, thereby preventing the formation of chips at the ground surface in the course of grinding operation.
摘要:
There is provided thermosetting resin compositions suitable for injection molding compounds having an apparent curing rate of 0.7 and 0.008 cm/sec respectively at 170.degree. C. and 110.degree. C. by a disk cure tester and an apparent activation energy of at least 26 Kcal/mol, by the addition of fluidity modifiers selected from ether compounds having methylene ether type structure, ester compounds having methylene groups connected with carbonyl ether groups and alcohol compounds having methylene groups connected with hydroxyl groups, to phenolic resin, hexamethylenetetramine, fillers and additives.