摘要:
A method of directly precipitating a spherical amorphous silica in a high yield by adding a carboxymethyl cellulose (CMC) as a coagulation growing agent in a step of neutralizing the alkali silicate with an acid. The CMC having a particular etherification degree and a particular polymerization degree is added in an amount of from 1 to 100% by weight reckoned as SiO.sub.2 with respect to silica in the alkali silicate, whereby the whole silica particles turn into spherical amorphous silica particles having high sphericalness. There can be obtained spherical amorphous silica particles having a BET specific surface area of from 25 to 800 m.sup.2 /g, an apparent specific gravity of from 0.1 to 0.8 and a particle diameter of from 0.2 to 50 .mu.m cheaply and in a high yield.
摘要:
A magnetic recording medium exhibiting not only good durability and traveling reliability but also improved static magnetic properties and electromagnetic transduction characteristics can be obtained according to the present invention. The magnetic recording medium includes a non-magnetic substrate and a magnetic layer composed of a magnetic powder, a binder and a lubricant, wherein the binder contains not less than 50% by weight of a polyester-polyurethane resin having a number-average molecular weight (Mn) of not greater than 15,000 and a ratio of a weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of not smaller than 2.5.
摘要:
The stretched film of the lactic acid-based polymer of the invention can degrade under natural environment, and additionally has an excellent mechanical strength and durability. By use of a lubricant in combination with an inorganic filler, these properties are further improved and thickness accuracy is enhanced. Consequently, the stretched film of the lactic acid-based polymer of the invention can be widely applied to a prepaid card and other various film materials, lamination materials and packaging materials. Even though abandoned after use in the natural environment, the stretched film relatively quickly decomposes into carbon dioxide and water and does not accumulate as waste.
摘要:
A brake force control device for a vehicle includes a master cylinder generating a brake pressure by operation of an operating member of the vehicle, a wheel brake for being mounted on a vehicle wheel and connected to the master cylinder through a conduit, a pressure control chamber connected to the wheel brake, a displacement actuator which varies the capacity of the pressure control chamber and an electric controller for operating the displacement actuator so as to supply the brake pressure to the wheel brake when the master cylinder does not generate the brake pressure.
摘要:
Disclosed are amorphous silica or silica-alumina spherical particles composed of X-ray diffractometrically substantially amorphous silica or silica-alumina, wherein individual particles have a definite spherical shape and a notched surface, the circularity (A) represented by the following formula: ##EQU1## wherein r1 stands for the radius of the circumcircle of the profile of the particle in an electron microscope photo thereof and r2 stands for the radius of the inscribed circle of the profile of the particle in the electron microscope photo, is in the range of from 0.90 to 1, the notching degree (B) represented by the formula: ##EQU2## wherein .DELTA.t stands for the depth between the peak and trough in the radial direction of notches on the profile of the particle in the electron microscope photo and r1 is as defined above, is in the range of from 1 to 10%, and the primary particle size (2r1) determined by the electron microscope method is in the range of from 0.1 to 20 .mu.m.
摘要:
Disclosed are a magnetic ribbon on at least one surface of which fine particles formed of a nonmagnetic inorganic substance having insulating properties are attached and a magnetic core around which this magnetic ribbon is wound or on which it is laminated. The fine particles serve as a spacer to form a layer of air between adjacent layers of the magnetic ribbon.
摘要:
The invention is a process for preparing amorphous silica alumina spherical particles by mixing sodium silicate or silicic acid gel with sodium aluminate and sodium hydroxide in an aqueous solution to form a gel, homogenizing the formed gel, crystallizing this intermediate product at 85.degree. C. to 200.degree. under atmospheric pressure or under hydrothermal conditions to form spherical zeolite particles with an x-ray diffraction pattern inherent to P-type zeolites and with a notched surface, treating the zeolite particles with acid to remove the sodium, thereby rendering the particles amorphous.
摘要:
An electronic air cleaner having therein an electrostatic precipitator and an ultraviolet sterilizing lamp is positioned close to an antenna of a radio receiver. A shielding cover lined with a thin metal film covers the lamp to block radiation of the electric noise waves generated by the lamp.