Abstract: The present invention discloses a rewritable phase-change optical disk having a recording material of a five-element alloy, Te—(Ge,Bi,Sb)—X, wherein X is B (boron) or C (carbon); Te (tellurium) ranges from 47 to 60 atomic percentage (at. %); Ge (germanium) ranges from 12 to 48 at. %; and Si (silicon) together with Sb (antimony) range from 5 to 41 at. %, based on the total atomic number of Te, Ge, Bi and Sb; and B or C range from 0.05 to 4 at. %, based on the total atomic number of Te, Ge, Bi, Sb and X.

Abstract: The present invention discloses a rewritable phase-change optical disk having a recording material of a five-element alloy, Te—(Ge,Bi,Sb)—X, wherein X is B (boron) or C (carbon); Te (tellurium) ranges from 47 to 60 atomic percentage (at. %); Ge (germanium) ranges from 12 to 48 at. %; and Si (silicon) together with Sb (antimony) range from 5 to 41 at. %, based on the total atomic number of Te, Ge, Bi and Sb; and B or C range from 0.05 to 4 at. %, based on the total atomic number of Te, Ge, Bi, Sb and X.

Abstract: This invention relates to a rewritable optical information recording medium of the phase-change type, which is made of a Te—Ge—Sb—B quaternary alloy. The optical contrast of the recording medium according to the present invention is enhanced over 35% in the visible wavelength range of 350 nm to 800 nm. Hence, the CNR of an optical disk with the recording medium of the present invention is increased, and the recording medium is suitable for optical information record operated in shorter visible wavelength. In addition, since the crystallization of the recording medium according to the present invention is single-phase, the performance of the repeated recording and erasing is enhanced.

Abstract: A nuclear medical drug for localize radiotheraphy of a tumor and methods for its preparation. The drug includes a radioactive ceramic or glass particle having biocompatiblity. Ceramic or glass particles prepared by traditional processes become radioactive particles with pure .beta.-particle-emitting radionuclides after being irradiated with an appropriate flux of neutrons. The radioactive particle with suitable particle size can then be dispersed into a contrast medium for injection or can be implanted by operation.

Abstract: The non-acicular modified maghemite and magnetite have high coercivity of, for the maghemite, up to 2200 Oe, saturation and residual magnetization of 63-85 emu/g and 43-52 emu/g, respectively; for the magnetite, the corresponding values are 800-1600 Oe, 82-87 emu/g, and 44-51 emu/g, respectively; while retaining same squareness ratio and same chemistry with conventional iron oxides, fine particle size of around 50 nm, easier dispersion and coating, invaried properties after curing, and low value of temperature coefficient of coercivity (0.24-0.37%/.degree. C. for the maghemite and 0.20-0.33%/.degree. C. for the magnetite), have been invented. They are thus especially suitable for high density recording. The modified maghemite and magnetite are prepared by precipitating from aqueous solution containing Fe, Mn, Co and Zn ions at proper ratio using an organic alkali as precipitant, followed by specific heat treatment sequences.

Abstract: A method for preparing a magnetic recording medium includes the following steps of providing a substrate; providing a solution consisting essentially of ions of cobalt, manganese and iron in deionized water; and preheating the substrate and spraying the solution onto the preheated substrate at an elevated temperature to uniformly distribute droplets thereon and form a magnetic recording medium film on the subtrate. Such method can prepare a magnetic thin film which has a high recording density and is cost-effective.

Abstract: A method for preparing a barium-ferrite-coated, needle-shaped .gamma.-Fe.sub.2 O.sub.3 magnetic powder of better properties is provided. The method includes the following steps of a) letting an iron-containing solution undergo a reaction to precipitate a needle-shaped .alpha.-FeOOH phase powder, b) mixing said .alpha.-FeOOH powder into a barium-containing solution in a predetermined Fe/Ba ratio, c) filtering without washing the precipitated powder, and d) subjecting the precipitated powder to heat treatments including calcination, reduction and oxidation.

Abstract: A method for preparing a magnetic recording medium includes the steps of providing a substrate, providing an alloy composite target attaching thereon Co and Fe pellets to modify the composition of this magnetic recording medium, and utilizing the target to form a (Co,Mn) modified .gamma.-Fe.sub.2 O.sub.3 thin film on the substrate under controlled conditions. Such method can provide a magnetic recording medium which is cost-effective and has a better SNR, a better resistance to corrosion and a high coercivity.

Abstract: A permanent magnet essentially consisting of in weight percent, 60% to 68% at least one transition element by weight, 30% to 38% at least one rare earth element by weight, 0.1% to 1.5% nitrogen by weight, and 0.8% to 1.5% boron by weight is disclosed. A method for producing the permanent magnet containing at least one rear element, at least one rare earth element, nitrogen and boron includes melting, cooling, milling, magnetizing, and compacting the transition element, the rare earth element and boron to form a green compact, and then sintering the green compact in nitrogen atmosphere having a constant partial pressure for 1 to several hours to form the permanent magnet.