A new technique is proposed for NMR image restoration from the influence of main magnetic field non-uniformities. This technique is applicable to direct Fourier NMR imaging. The mathematical basis and details of this technique are fully described. Modification to include image restoration from non-linear field gradient influence is also presented. Computer simulation demonstrates the effectiveness of this technique for both Fourier zeugmatography and spin-warp imaging.

No abstract

A dry two-stage low NOx combustor for a 73 MW gas turbine has been developed to meet stringent NOx limitations in Japan. This combustion system has a fuel-air control mechanism to ensure stable switching from one-stage combustion to two-stage combustion. NOx emission is very low not only at full load but also in the entire gas turbine operating range. The NOx characteristics have proved to be within the goal in full scale, full pressure combusion tests. This paper outlines the development plan and describes the structure and combustion characteristics of the low NOx combustor.

No abstract

The method used in this study employs a multi-element transducer. Each transducer element transmits successive cylindrical sound waves at a predetermined interval. During the transmission intervals, all elements receive echos from targets. A digital processor then distributes the amplitude data of these echos on elliptic addresses located in a digital memory system. The relation between sound propagation time and element location determines these elliptic addresses. The resolving power is estimated to be the same as that of a cylindrical transducer measured at the focal point for pulse-echo mode operation. The results of numerical analyses agree well with the estimated values and indicate a high resolving power within the entire imaging plane. A prototype system utilizing this method, containing a 32-element transducer and a mini computer, is used to complete some experimental imaging of stationary targets and the obtained images are discussed.