Abstract: A semiconductor storage device that is capable of improving reliability includes: a non-volatile memory provided with a block including a plurality of memory cell transistors connected to a word line; and a controller configured to monitor a threshold voltage distribution width of the plurality of memory cell transistors after performing at least one of an erasing operation on the block and a preliminary write operation on the plurality of memory cell transistors and to classify the plurality of memory cell transistors according to the threshold voltage distribution width of the plurality of memory cell transistors.

Abstract: A polyacetal resin composition which has improved friction-wear characteristics as compared with conventional polyacetal resin compositions and which is less restricted in counter sliding members and can conform to a wide range of friction-wear conditions. A polyacetal resin composition comprising 100 parts by weight of (A) a polyacetal resin, 0.1 to 10 parts by weight of (B) a polyethylene wax having a number average molecular weight of 500 to 15,000, 0.1 to 10 parts by weight of (C) a polyethylene resin having a number average molecular weight of 2×104 to 50×104, and 0.1 to 5 parts by weight of (D) a silicone oil having a kinetic viscosity at 25° C. of 50×104 cSt or more.

Abstract: A polyacetal resin composition which has improved friction-wear characteristics as compared with conventional polyacetal resin compositions and which is less restricted in counter sliding members and can conform to a wide range of friction-wear conditions. A polyacetal resin composition comprising 100 parts by weight of (A) a polyacetal resin, 0.1 to 10 parts by weight of (B) a polyethylene wax having a number average molecular weight of 500 to 15,000, 0.1 to 10 parts by weight of (C) a polyethylene resin having a number average molecular weight of 2×104 to 50×104, and 0.1 to 5 parts by weight of (D) a silicone oil having a kinetic viscosity at 25° C. of 50×104 cSt or more.

Abstract: The present invention relates to a polycarbonate resin composition comprising 100 parts by weight of an aromatic polycarbonate resin (a), 3 to 30 parts by weight of titanium oxide (b), 0.01 to 9 parts by weight of silica (c1), 0.01 to 9 parts by weight of a polyorganosiloxane polymer (c2), and 0.01 to 5 parts by weight of polytetrafluoroethylene (d).

Abstract: The present invention relates to a polycarbonate resin composition comprising 100 parts by weight of an aromatic polycarbonate resin (a), 3 to 30 parts by weight of titanium oxide (b), 0.01 to 9 parts by weight of silica (cl), 0.01 to 9 parts by weight of a polyorganosiloxane polymer (c2), and 01 to 5 parts by weight of polytetrafluoroethylene (d).

Abstract: A method for preparing a modified optically isotropic pitch comprising, preparing a synthetic pitch by reacting a member selected from the group consisting of a conjugated polycyclic hydrocarbon containing a low molecular weight alkyl group or a material containing such a substituted hydrocarbon in the presence of hydrofluoric acid/boron trifluoride, and treating the synthetic pitch by passing an oxidizing gas through the synthetic pitch at elevated temperatures.

Abstract: A method for the desulfurization of hydrocarbons by desulfurizing unsaturated hydrocarbons or hydrocarbon materials containing unsaturated hydrocarbons, in the presence or absence of hydrogen, using a copper-zinc desulfurizing agent prepared by the co-precipitation method. By this method, the sulfur content of the hydrocarbons can be reduced while suppressing hydrogenation of the unsaturated hydrocarbons.

Abstract: A method for preparing a modified optically isotropic pitch comprising, preparing a synthetic pitch by reacting a member selected from the group consisting of a conjugated polycyclic hydrocarbon containing a low molecular weight alkyl group or a material containing such a substituted hydrocarbon in the presence of hydrofluoric acid/boron trifluoride, and treating the synthetic pitch by passing an oxidizing gas through the synthetic pitch at elevated temperatures.

Abstract: Mesophase pitch that has a softening point of no more than 250.degree. C., a pyridine-insolubles content of no more than 50% and a n-heptane solubles content of 3-10%, with the n-heptane solubles experiencing a weight loss of no more than 15% at 450.degree. C. as measured by thermogravimetry is produced by polymerizing a condensed polycyclic aromatic hydrocarbon or a substance containing it in the presence of HF and BF.sub.3. This mesophase pitch is suppressed satisfactorily in its tendency to smoke during spinning and, additionally, it has a low enough softening point to exhibit outstanding spinnability. Hence, the pitch allows for high-volume spinning to be performed continuously for a prolonged time without causing extensive fouling of the surface of spinning nozzles.

Abstract: A heat-resistant resin composition comprising a melt-kneaded product of:(A) at least one member selected from the group consisting of a polyamideimide resin precursor composed mainly of a recurring unit of the formula (1)-a, ##STR1## wherein R is a divalent aromatic group or aliphatic group, R.sup.1 is a hydrogen atom, an alkyl group or a phenyl group, and Ar is a trivalent aromatic group composed of at least one six-membered ring, and a polyamideimide resin composed mainly of a recurring unit of the formula (1)-b, ##STR2## wherein R, R.sup.1 and Ar are as defined in the above formula (1)-a, (B) a polyphenylene sulfide resin, and(C) an organic isocyanate compound having at least two isocyanate groups in the molecule, the amount of said organic isocyanate compound being 0.5 to 5 parts by weight based on 100 parts by weight of the total amount of the compounds (A) and (B).