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Stress and strain tolerance is investigated for jelly roll (JR)-processed rapid-heating, quenching and transformation annealing (RHQT) Nb[subscript 3]Al superconductors. Results are enumerated and discussed.

Corrosion of steel exposed to magnetic fields is reported. The relationship between corrosion patterns and magnetic-field gradients near the steel is discussed.

We have already reported the best critical current density of 66,000 A/[cm.sup.2] with an Ag sheathed Bi-2223 tape conductor. The Brick-wall model is for explaining the current transport mechanism of this conductor. The model has its roots in the fact that the Bi-2223 tape core is a complicated stack of crystals which have a mica-flake structure. The orientation of the crystals seriously affects the current transport capability. Moreover, the contacts between the stacking crystals are very important. The transport current flows dividing into many branch paths. Under high magnetic field, the different paths experienced different electromagnetic forces. Differences between the electromagnetic forces on the different crystals can affect the contacts so as to increase resistivity and decrease overall critical current density of the tape. This effect can foretell the limit of the critical current density obtainable with these kind of conductors.

Co-Pt and Si[O.sub.2] granular films were prepared on a Cr seed layer. Co-Pt grains dispersed in the Si[O.sub.2] matrix discretely. Conical grains grew in contact with the Cr layer and spherical grains grew between the conical ones. Coercivity exceeded 2 kOe and coercive squareness reached about 0.7 at a remanent magnetic moment of 0.4 memu/[cm.sup.2]. Activating magnetic moment was [10.sup.-15] emu and the index of the thermal stability was about 100. Bit error rate was held below [10.sup.-5] up to a linear density of 280 kfci. The recording pattern at the track width of 1[[micro]meter] was clearly visible. The Co-Pt and Si[O.sub.2] granular media have potential for 5 Gb/[in.sup.2] recording. Index Terms - Bit error rate, granular media, magnetic properties, micro-structure.

Two superconducting coils were constructed as part of a study on the characteristics of bismuth-based superconductors. The coils were built of silver-sheathed high-temperature superconducting wires made by the powder-in-tube process. One is designed for a 0.2-T iron core magnet that operates at 77.3 K while the other is an insert coil for a hybrid magnet that induces 0.8 T with a background field of 7 T at 4.2-K operation.

Abstract:A novel single-ended push pull (SEPP)soft-switching high-frequency inverter for induction-heating applications with a continuous output power regulation scheme at a .xed frequency incorporating a novel lossless snubber circuit is presented.Conventional SEPP high- frequency inverters have been .nding their home-electronic applications owing to their simpli .ed circuit constitutions.However,their soft-switching operations were restricted in a relatively narrow output power range when they were controlled by a PWM technique.The proposed high- frequency inverter topology is based on the conventional SEPP high-frequency inverter together with a novel lossless snubber circuit operated at an auxiliary resonant frequency so that it can be operated under soft-switching as well as PWM regulations.Hence,the soft-switching operation range of the proposed inverter can be widened considering accompanied by a high ef .ciency compared with the conventional SEPP inverter.Uses can include a home-cooking application with a high thermal ef .ciency and high safety at a .xed frequency of 20 kHz.The operating principle,is described and the results of computer-aided simulation analysis of the circuit operation and evaluation of the performance of the proposed inverter are given,which show its high utility. [ABSTRACT FROM AUTHOR]

A ZCS high frequency inverter with a fixed frequency voltage regulation scheme regulated by an instantaneous current-vector control is presented. Its total conversion efficiency reaches 90% owing to its soft switching operation. It is based on a conventional voltage-fed seriesresonant half-bridge inverter, which incorporates reverse-blocking two-terminal quasi-resonant ZCS cells and utilises B-SITs as switching power devices. Thus, high conversion efficiency is attained. Its maximum voltages across active switching power devices are clamped to the DC source voltage so that the voltage rating of the switching power device can be suppressed at a lower level. Since the output power of the inverter depends on the value of impedance of the resonant load circuit, it should be determined at the most suitable value, which is, however, relatively low. Consequently, a working coil with a low inductance is required. On the other hand, its output power is decreased considerably for a working coil with a high inductance. To solve this problem, a dual-resonant load circuit topology is introduced into the inverter circuit so that it can meet various loads. Next, the reverse-conducting ZCS inverter topology incorporating the reverse-conducting two-terminal quasi-resonant ZCS cells with its circuit operation and performance is described. In addition, a breadboard of this inverter is prepared and operated at 200 kHz for induction heating of an aluminium vessel with a sufficient efficiency. Note that induction heating of nonmagnetic material such as the aluminium vessel has been considered technically difficult. [ABSTRACT FROM AUTHOR]

Examines voltage-fed full-bridge series resonant inverters that use static induction transistors. Control implementation; Inverter operation; Characteristics from the viewpoint of practical operation.

A design method for a code-matched symbol-interleaver for turbo trellis-coded modulation is proposed. The method constructs an interleaver by code matched criteria to eliminate some input error events of low symbol Hamming weight (SHW) sequences of the code which can produce low SHW codewords. Numerical results confirm that the interleaver can lower the error floor at moderate to high signal-to-noise ratio. [ABSTRACT FROM PUBLISHER]