Abstract: A secondary storage device using a nonvolatile semiconductor memory in which individual block areas constituting the nonvolatile semiconductor memory can be used up to their limit of use. When the number of repetitions of erasure in a second block area has reached a predetermined reference value, a searching unit searches active block areas for an alternate block area. A second writing unit writes information which has been stored in the alternate block area, into the second block area. A second correspondence modifying unit associates the physical block number with the logical block number and causes a logical-physical correspondence storing unit to store the correspondence of the thus-associated block numbers. A second erasing unit erases the information stored in the alternate block area and treats the block area with the physical block number as a spare block area.

Abstract: An arithmetic circuit with a small number of parts performs high-speed arithmetic operations for calculating a square-root of a sum of squares of two numbers. Absolute values of two inputs S.sub.in1 and S.sub.in2 are determined by absolute value calculators and are compared by an absolute value comparator According to the comparison result, a first multiplexer selects the smaller of the two absolute values and a second multiplexer selects the larger of the two absolute values. The smaller absolute value is shifted by a 2-bit right shifter and by a 3-bit right shifter respectively, and the obtained shifted results are added together by a (N-2)-bit adder. The sum of the shifted values is then added by a N-bit adder to the larger absolute value. A square-root of the square-sum of two inputs S.sub.in1 and S.sub.

Abstract: A protocol conversion system that provides improved reliability in data transmission and reception. The system comprises a first node belonging to a network A, a second node belonging to another network B, and a protocol converter disposed between the two nodes. The first node uses a first communications protocol that defines a set of rules for communications in the network A, while the second node uses a second communications protocol for the network B. Serving as a relaying device between the first node and second node, the protocol converter converts the communications protocol of the messages traveling between them. The protocol converter comprises a first message processor to process the messages according to layer definitions of the first communications protocol, a second message processor to process the messages according to layer definitions of the second communications protocol, and a first protocol converter that adds and removes some control information to/from the messages for protocol conversion.

Abstract: An apparatus for generating a modulated magnetic field includes a magnetic head coil and a pair of additional inductive coils. The ratio of the average inductance of the additional inductive coils to the inductance of the head coil is from 2 to 8. The apparatus ensures a magneto-optical recording system of the magnetic field modulation mode having an increased switching speed and a minimized overshoot of recording current.

Abstract: An apparatus for controlling synchronization in a system having at least first and second units each having internal circuits includes signal paths through which a control signal output from a second unit is sent to a first unit and a control signal output from the first unit is sent to the second unit. A first preparatory process part carries out a process to place the internal circuits of the second unit in an operating state when the second unit is connected to the system and for outputting a control signal to the signal paths. A first function mask control part is provided for stopping the operation of the internal circuits of the second unit when a control signal from the first unit is not received by the second unit, and for restarting the operation of the internal circuits when the control signal is received.

Abstract: An improved information-modulate magnetic field generating circuit for magneto-optical recording which uses a step-down transformer whose secondary winding has less turns than the primary winding, thus permitting substantial reduction of electric power for driving the magnetic head coil.

Abstract: Magneto-optical recording method for a magneto-optical recording disk using a non-flying magnetic head. The magnetic head produces a magnetic field extending from a primary magnetic pole and returning to an auxiliary magnetic pole while the disk is rotated. The magnetic head is spaced apart from one major surface of the disk such that the primary magnetic pole applies a magnetic field across the disk. Magneto-optical recording is effected in a magnetic field-modulation mode while properly controlling the projected area of the primary magnetic pole and the distance between the magnetic head and the disk surface. A satisfactory C/N is obtained in a consistent manner while jitter is reduced.

Abstract: A nuclear magnetic resonance multi-echo imaging method and an apparatus therefor in which gradient field pulses having predetermined products of intensity and time are applied on both sides of an inversion pulse in at least two of three directions which are orthogonal to each other to dephase components of a magnetization vector which leads to an artifact signal and an error signal, whereby only a normal echo signal can be sampled to form a correct image.

Abstract: In an NMR imaging method of distinguishing two chemical shifts of unclear spins and obtaining respective spin distribution images, 180.degree. RF. pulses are applied twice to generate two spin echoes after spins of an object for inspection have been exicted. In the second echo among them, a pulse time-interval is so set that the time difference between the Hahn echo and the gradient echo may provide two chemical shifts with a phase difference of 2n.pi.. On the basis of information representing the distribution of a static magnetic field included in an image obtained from the second pulse, an image obtained from the first echo is compensated. By using the compensated image, spin distribution images with two chemical shifts distinguished are obtained.

Abstract: An NMR spectroscopic imaging method of obtaining separate spin distribution images for respective spectral components of the spectrum of an NMR signal caused by the chemical shift of nuclides of interest in an object includes providing for a transversal magnetization signal of the object placed in a static magnetic field. A position of the signal in a phase domain is translated in a K-space from the origin thereof. Further, the signal is sampled while rotating a position of the signal in the K-space plural times on a certain circle in the K-space by applying a rotating field gradient, thereby to obtain a group of signal data. Signal data trains each of which is composed of signal data present at the same position on the K-space in the signal data group obtained by the sampling during the plural signal rotations, is subjected to Fourier transformations, respectively, thereby effecting a spectral analysis of the NMR signal.

Abstract: Disclosed in a nuclear magnetic resonance (NMR) based inspection apparatus using an SQUID flux meter for detecting a small NMR signal, in which a receiving coil for receiving the NMR signal from an object is connected to a mixer, which mixes a reference high-frequency signal with the NMR signal so that the NMR signal is reduced to a low-frequency signal having a differential component of frequencies of both signals, and the low-frequency signal is applied to the input coil of the SQUID flux meter so that it is converted into a voltage signal. The mixer circuit includes Schottky diodes operative at a liquid helium temperature or Josephson junctions, and the portions of apparatus from the reception coil up to the SQUID flux meter are operated in a superconductive state at a liquid helium temperature.

Abstract: Method for measuring the time dependence of an oscillating field gradient and representatively its integral function with respect to time for imaging method using the field gradient such as rapid chemical shift imaging method echo planar method, etc. A uniform specimen is placed within a coil of an NMR device, in which nuclear spins are excited; a phase encoding field gradient is applied thereto; and signals are sampled under application of the field gradient to be measured. These steps are repeated and an integral function of the field gradient with respect to time is obtained by using the peak position in the series of data obtained by this repetition.

Abstract: An Alderman high-frequency coil used for generating or detecting a high-frequency magnetic field in an NMR apparatus comprises two ring-shaped inner conductors aligned coaxially with a spacing being made therebetween and two outer conductors disposed to surround the inner conductors. The outer conductors are each split along the current path to form a 4-piece outer conductor.

Abstract: An NMR imaging method which provides a three-dimensional image representative of the two-dimensional distribution of nuclear spin species resolved by chemical shift or the local spectra resolved by two-dimensional location. After the excitation of nuclear spins and the phase-encoding by application of a field gradient G.sub.y, a periodically inverting field gradient G.sub.x is generated to yield a continuous echo train. The echo train is sampled and separated into data of odd-numbered echoes and data of even-numbered echoes which data are in turn reconstructed into two-dimensional data arrays, respectively. The data thus reconstructed are three-dimensional Fourier-transformed.

Abstract: An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 wherein the .alpha.-olefin polymer is a homopolymer made up of a C.sub.10 to C.sub.25 alpha-olefin monomer or is a copolymer made up of a monomer mixture comprising more than 50 wt. % of at least 2 C.sub.10 to C.sub.25 alpha-olefin monomers and a melt index greater than 1.8 g/10 min. and (B) an olefin vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt. % and an average molecular weight of from about 50,000 to 1,000,000 and a melt index greater than 2 g/10 min. The .alpha.

Abstract: An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 wherein the .alpha.-olefin polymer is a homopolymer made up of a C.sub.10 to C.sub.25 alpha-olefin monomer or is a copolymer made up of a monomer mixture comprising more than 50 wt. % of at least 2 C.sub.10 to C.sub.25 alpha-olefin monomers and a melt index greater than 1.8 g/10 min. and (B) an olefin vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt. % and an average molecular weight of from about 50,000 to 1,000,000 and a melt index greater than 2 g/10 min. The .alpha.

Abstract: In a solvent dewaxing process wherein a waxy hydrocarbon oil is mixed with a dewaxing aid and dewaxing solvent and chilled to form a slurry comprising solid particles of wax and a mixture of dewaxed oil and solvent, the improvement which comprises using a polymeric dewaxing aid comprising a condensation product of naphthalene and chlorinated wax having an average molecular weight ranging from about 20,000 to 500,000 and a molecular weight distribution exceeding the range of from about 10,000 to 1,000,000.

Abstract: In a solvent dewaxing process wherein a waxy hydrocarbon oil is mixed with a dewaxing aid and dewaxing solvent and chilled to form a slurry comprising solid particles of wax and a mixture of dewaxed oil and solvent, the improvement which comprises using a polymeric dewaxing aid comprising a condensation product of naphthalene and chlorinated wax having an average molecular weight ranging from about 20,000 to 500,000 and a molecular weight distribution exceeding the range of from about 10,000 to 1,000,000.

Abstract: Dewaxing aid used in a solvent dewaxing process is recovered in wax bottoms from slack wax by vacuum distilling the slack wax to about 5-10 wt. % bottoms at a temperature no greater than about 320.degree. C. The dewaxing aid-containing wax bottoms is recycled back into the dewaxing process by adding same to the wax-containing oil feed in an amount ranging from about 0.5-5 wt. %. This has been found to be particularly advantageous when the dewaxing aid is an .alpha.-olefin copolymer, a chlorinated paraffin/naphthalene condensation product and mixture thereof because of their thermal stability.

Abstract: An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 and (B) an olefin-vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt.% and an average molecular weight of from about 50,000 to 1,000,000. The .alpha.-olefin polymer having a high molecular weight and wide molecular weight distribution, when combined with the olefin-vinyl acetate copolymer, synergistically improves the efficiency of wax separation.