Abstract: It is provided a novel method of producing polarization inversion parts by electric field polling process wherein the polarization inversion part extends to a deeper point from the surface of a substrate. The polarization inversion part is produced by electric field polling process using a comb electrode having a plurality of electrode portions 5 and a feeding portion 1. Each electrode portion 5 has a base portion 6 extending from the feeding portion 1 and a plurality of conductive portions 5a, 5b and 5c separated from the base portions 6, and the conductive portions have an average length “d” of 4 ?m or longer and 9 ?m or shorter. Alternatively, each electrode portion 5 has a base portion 6 extending from the feeding portion 1 and a plurality of conductive portions 5a, 5b and 5c separated from the base portion 6, and the conductive portion 5b at the tip end of the electrode portion has a length “db” smaller than the length “da” of the conductive portion 5b nearest to the base portion.

Abstract: A comb electrode 3 is provided on a first main face 2a and a uniform electrode 4 is provided on a second main face 2b of a substrate made of a ferroelectric single crystal of a single domain, and a voltage is applied on the comb electrode 3 and the uniform electrode 4 to produce domain inversion part. It is laminated, on the substrate, an underlying substrate comprising a main body 5, a first conductive film 6 provided on a first main face 5a and a second conductive film 7 provided on a second main face 5b of the main body 5. The uniform electrode 4 is electrically conducted with the first conductive film 6 and a voltage is applied on the comb electrode 3 and the second conductive film 7 to form a domain inversion part in the substrate 2.

Abstract: A first electrode and a second electrode are provided in separation on a main surface of a substrate made of a ferroelectric single crystal. A first voltage is applied between the first electrode and the second electrode, for example, on condition that the first electrode is positive and the second electrode is negative, to generate and grow a first polarization-inverted portion toward the second electrode from the first electrode. Then, the distance between the first electrode and the second electrode is changed, and a second voltage is applied between the first electrode and the second electrode on the same condition, to generate and grow a second polarization-inverted portion, in a different area from that of the polarization-inverted portion, toward the second electrode from the first electrode.

Abstract: A first electrode and a second electrode are provided in separation on a main surface of a substrate made of a ferroelectric single crystal. A first voltage is applied to between the first electrode and the second electrode, for example on condition that the first electrode is positive and the second electrode is negative, to generate and grow a first polarization-inversed portion toward the second electrode from the first electrode. Then, the distance between the first electrode and the second electrode is changed, and a second voltage is applied to between the first electrode and the second electrode on the same condition, to generate and grow a second polarization-inversed portion, in a different area from that of the first polarization-inversed portion, toward the second electrode from the first electrode.

Abstract: In order to realize server switching to a backup server from a working server without changing any setting on a client computer, a network system is provided having a network supervising means for supervising operations of a plurality of server computers connected to the network, a server switching means for realizing server switching in which the backup server computer alternatively executes the server function of the working server computer by virtually setting the address of the working server computer connected to the network as the address of the backup server computer. A packet converting means is provided for converting the packet transmitted and received between the working server computer and the client computer into the packet transmitted and received between the backup server computer and the client computer.

Abstract: A packet broadcasting method broadcasts a data packet sent by a broadcasting source terminal to a number of broadcast destination terminals. A broadcasting apparatus having a peculiar DTE address is provided in a packet switching system and a broadcasting table having one or a plurality of broadcasting source terminals is defined in the broadcasting apparatus. The broadcasting apparatus registers a terminal other than a broadcasting source terminal into the broadcasting table as a broadcast destination terminal in response to a call set-up from such a terminal When the broadcasting apparatus receives a data packet from the broadcasting source terminal, a data packet having the same data as the received data packet is sent to the broadcast destination terminal.

Abstract: A tomographic image of a X-ray tested tissue of body is reconstructed by calculating X-ray absorption coefficients of picture elements constituting a tomographic plane in reference to measured values produced by the first and second projectional distributions of X-ray produced by projecting X-ray. Accordingly, it becomes possible to reconstruct a clear tomographic image of a moving X-ray tested tissue and to make an X-ray exposure level very low by extremely shortening the time of the reconstruction of computed tomographic image. Moreover, a resolving power of measuring is substantially improved, resulting in that an accuracy of reconstructing the tomographic image may also be improved.

Abstract: A method of reconstructing a computed tomographic image comprising projecting X-rays through material to be tested at a plurality of spaced positions, and measuring the X-ray density values of the X-rays projected through the material along the distribution of projected X-rays. The spaced positions at which the X-ray density values are measured are selected such that the tomographic plane of the material to be reconstructed is represented by a pseudo-tomographic plane comprised of an array of n rows of m columns of picture elements, each having a single piece of X-ray density information, and such that each X-ray beam passes through the lower left corner of a corresponding picture element. The X-ray absorption coefficient for each picture element is calculated from the measured values of X-ray density, and the computed tomographic image is reconstructed by positioning picture elements having the computed X-ray absorption coefficients in an array corresponding to the array in the pseudo-tomographic plane.

Abstract: Measured values are produced from one of a plurality of projectional distributions of X-ray being constituting the major data, other measured values are produced from the remaining projectional distributions of X-ray constituting sub-data, X-ray absorption coefficient for picture elements constituting a tomographic plane is calculated to construct a tomogram of the X-ray tested tissue of body, resulting in that a substantial decrease of the measuring time will decrease exposure time to X-ray and/or enable a clear reconstruction of a moving X-ray tested tissue of a body as well as improve substantially and the accuracy of reconstruction.