1,1-bis-(4,4'-diethylaminophenyl)-4,4-diphenyl-1,3-butadiene (DEPB) and N,N'-diphenyl-N,N'-bis-(3-methylphenylene)-1,1'-diphenyl-4, 4'-diamine (TPD) are used as organic photoconductors (OPC) and as hole transport materials for organic light-emitting diodes (LED). The hole mobilities of cast or vapour-deposited DEPB and TPD films are measured using the time-of-flight method. The hole mobility of a cast DEPB/polycarbonate film increases with the concentration of DEPB, but the cast pure DEPB film could not be prepared because of crystallization. Since crystallization in a vapour-deposited DEPB film proceeded very slowly, it was possible to measure the hole mobility, which is 5-8*10-5 cm2 V-1 s-1. The hole mobilities of TPD films were consistent with those reported by Abkowitz et al. (1986). The hole mobility of vapour-deposited TPD film was several times 10-4 cm2 V-1 s-1 and the electric field dependence of its hole mobility was consistent with that for a cast pure TPD film. In other words, it is possible to estimate the mobility of vapour-deposited OPC material by measuring that of a cast pure OPC film, for cases when a relatively thick, vapour-deposited OPC film is difficult to prepare.

The authors investigated the electrical conduction and electroluminescence in evaporated thin films for 1,1-bis-(4,4'-diethylaminophenyl)-4,4-diphenyl-1,3-butadiene (DEPB) which can be used as the carrier transport layer of electrography. Holes are the majority charge carriers for electrical conduction in DEPB thin films. The current in DEPB thin films below 1 MV cm-1 and at -160 degrees C is of Schottky type. Currents below 0.3 MV cm-1 and above -80 degrees C are attributable to the space-charge-limited current. Those above 1 MV cm-1 and above -80 degrees C result from the tunnelling-type current. Currents in DEPB thin films are accompanied by electroluminescence (EL). The EL intensities increase with current. The emitting region in DEPB is the whole bulk material.

In this paper, simultaneous optimization is carried out for successive two cycles of pressurized water reactors. At first, a simplified problem of the simultaneous optimization was studied by assuming the batch-wise power sharing as independent variable, i.e., batch-wise power sharing was optimized without considering corresponding loading patterns. The optimization of the batch-wise power sharing was carried out for the conventional single cycle, the equilibrium cycle and the two successive (tandem) cycles. The analysis indicated that the tandem cycle optimization well reproduce that of the equilibrium cycle optimization, which is considered as a typical case of the true multicycle optimization. Next, simultaneous optimization of loading patterns for tandem cycles is carried out using the simulated annealing method. Since the design space of the tandem cycles optimization is much larger than that of the conventional single cycle optimization, the optimization condition (i.e., number of calculated patterns) are established through sensitivity study. The optimization results are compared with those obtained by the successive single cycle optimizations and it is clarified that the successive single cycle optimization well reproduces the optimization results obtained by the simultaneous optimization if objective functions are appropriately chosen. The above result will be encouraging for the current in-core optimization method since single cycle optimization is utilized due to limitation of computation time.

In this paper, simultaneous optimization is carried out for successive two cycles of pressurized water reactors. At first, a simplified problem of the simultaneous optimization was studied by assuming the batch-wise power sharing as independent variable, i.e., batch-wise power sharing was optimized without considering corresponding loading patterns. The optimization of the batch-wise power sharing was carried out for the conventional single cycle, the equilibrium cycle and the two successive (tandem) cycles. The analysis indicated that the tandem cycle optimization well reproduce that of the equilibrium cycle optimization, which is considered as a typical case of the true multicycle optimization. Next, simultaneous optimization of loading patterns for tandem cycles is carried out using the simulated annealing method. Since the design space of the tandem cycles optimization is much larger than that of the conventional single cycle optimization, the optimization condition (i.e., number of calculated patterns) are established through sensitivity study. The optimization results are compared with those obtained by the successive single cycle optimizations and it is clarified that the successive single cycle optimization well reproduces the optimization results obtained by the simultaneous optimization if objective functions are appropriately chosen. The above result will be encouraging for the current in-core optimization method since single cycle optimization is utilized due to limitation of computation time.