A Design Study of A Magnetron Injection Gun for A Gyrotron Oscillator

A magnetron injection gun has been designed for an X-band gyrotron oscillator. The design is based on two-dimensional numerical analyses of the equi-potential surfaces and the electron trajectories. The gun can produce a helical beam of electrons with large perpendicular velocities to the magnetic field. The positional velocity spread of the emitting electrons remains within 12% just before injection into an open resonator. The variation of the velocities along the trajectory is studied and compared with that predicted by the adiabatic approximation. The approximation may yield an appreciable deviation due to the neglect of the inward drift of electrons. Typical parameters of the designed electron gun are presented

A Study on Plasma Diffusion in a Uniform Magnetic Field

Through gas plasmas of very low charge densities, electrons and ions diffuse freely because the space charge is negligible (free diffusion limit). On the contrary at high charge densities, the space-charge induced field saturates and causes the ambipolar diffusion which is a combination of diffusive and saturated mobility flow (ambipolar limit). The transition from the ambipolar to the free diffusion is studied for the case of magnetized slab plasmas maintained in between two plane-walls through ionization by electron collision. The basic equation is nonilnear because of the mobility flow due to the spacecharge field. A simple analytic approximation is applied to the distribution of charged particles. The amplitude of charged particle distribution and the plasma thickness are determined by an iterative numerical procedure. For typical values of the characteristic plasma parameters for magnetized hydrogen plasmas, variation of the charged particle density through the transition between both limits is investigated. Spatial distributions of electrons and ions inside the plasma slab are calculated

A Study on the Space and Energy Dependent Reactor Kinetics, with Direct Physical Interpretation of the Effective Neutron Lifetime and Criticality Factor

First, the concept of neutron importance is introduced. It is assumed that each of the neutrons produced by fission in a chain reactor possesses an importance proportional to the number of its descendants. Secondly, on the basis of the law of conservation, a transport equation of the neutron importance is derived. Then, the effective neutron lifetime is defined as the mean interval of successive fission events in the course of the importance transport. The consistent definition of the criticality factor is the neutron multiplicity during the effective neutron lifetime so defined. After defining the basic reactor kinetics parameters, such as the effective neutron lifetime and criticality factor, the persistent time behavior of nuclear chain reactors has been investigated. The kernel form reactor equation is used because of its physical intelligibility. The formulas obtained are applicable to any reactor, provided that the neutron flux and its adjoint function is known either analytically or numerically

Estimation of Annual Average Thermal Efficiency of Modern Steam Power Plants in a Large Hydro-Steam Combined Electric Power System

One of the fundamental problems in planning steam electric power generation is to estimate its annual average thermal efficiencies for a projected plant in a given electric power system. The following discussion is mainly concerned the estimation of thermal efficiency of modern type steam electric power plant to be put into the system operation

A Method for Estimating the Power Duration Curves of the Project Power in a Large Combined Hydro-Steam Power System

In planning electric power generation of a large combined hydro-steam power system, we should determine not only the power and energy but also the power duration curve, which is necessary to calculate the energies, generating hours and start-stop frequencies of each generating unit. The project power, which includes the existing steam power, will be found from the predicted load after subtracting the part assigned to the existing hydro plants. In general, the past data show that the curve, represented by the vertical distance between the duration curves of load and that of hydro power, will be greatly different from the steam power duration curve of the corresponding year. In this paper, the authors try to find out a method in which the duration curves of the predicted steam power, estimated by utilizing the past data of load and hydro power, are closely matching with the actual duration curve of steam power in the corresponding year. The diagrams, calculated by this method from the past data of a certain power system, are expected to be applicable in estimation of the duration curves of project power in near future, at least for the same power system

The S₄ and Few-Group Diffusion Calculations of Fast Reactors

To economize a large amount of numerical work in the calculation of fast breeders, the present work has been done in the hope that few-group diffusion theory might give acceptable results in some cases. A hypothetic 233TJ-232Th system with large core size (～670/) as well as a hypothetic 239Pu-238U fast reactor with small core size (～50l) are adopted. These systems are assumed to be of spherically symmetric geometry. One dimensional calculations are applied to obtain the static characteristics of the systems. The results from few-group S4 and diffusion method are investigated. These results seem to indicate that fouror three-group diffusion calculation might at least be used in place of three-group S4 computation for both large and small fast reactors. A new convergence criterion imposed upon the static parameters is proposed. The leakage rate of neutrons from the blanket is selected as the sensitive measure of convergence. This rate is estimated in two ways, i.e. with the aid of neutron current and by neutron inventory. The sufficiently converged state can be reached when these two values coincide with each other. One is also able to infer the necessary number of spatial mesh points by comparing these two values

The Selection of the Representative Year of Stream Flow for Electric Power Generation

An analysis of the actual state of the combination of the load and the hydro-and steam-power in a large combined hydro-steam power system is necessary for any economic comparison between various types of hydro- and steam-power generation; and for the power generation by a plant of the run-off-river type as well as of the pondage and storage types, it sometimes involves an inspection of the daily stream flow in connection with the daily load curve throughout a year. In such cases, it being difficult to draw a daily stream flow diagram for the future, it sometimes becomes necessary to select the representative year representing a typical stream flow from the data in the past. This paper describes the method for its selection

Estimation of the Average Stream Flow in the Immediate Future for Hydro-electric Power Generation

In making an economical study of a large combined hydro-steam power system, it is necessary to estimate the annual average available power of the rivers for any given year in the immediate future, and, especially for the control of a plant of pondage or storage type, to estimate the drought-seasonal average stream flow during the coming winter. In this paper we shall study the method for estimating the annual average stream flow by means of the theoretically based method of statistical extrapolation, and the method for estimating the drought-seasonal average stream flow during the coming winter by means of the method of statistical extrapolation for a time series with two members, by analysing the existing data of the seasonal average stream flows during winter and autumn over a number of recent years, including that for autumn of the estimated year, taking the data of certain rivers as examples

Metal complex oligomer and polymer wires on electrodes: Tactical constructions and versatile functionalities

AbstractThis review covers recent progress in the construction of metal complex wires on various substrates via the stepwise coordination method, their functions, and the electrochemical evaluation of bis(terpyridine)metal complex oligomer wires on electrodes. In the layer-by-layer process of metal complex wire construction, various combinations of anchor ligands, metal sources, and bridging ligands have been used. The prepared structures show multiple functions, including photocurrent generation, catalytic activity, insulation properties, and long-range electron transport abilities. The electron transport behavior, and the long-range electron transport abilities from the terminal redox site to the electrode via bis(terpyridine)metal complex wires, were evaluated using potential step chronoamperometry. The remarkable long-range electron transport abilities were evidenced in the small values for the attenuation factor, β. The influence of the building blocks in the metal complex wires on the β value and the electron transfer rate constant was demonstrated