More accurate measurement of the vibrational temperature for a DC-glow discharge plasma with N₂ gas has been attempted using the spectroscopic diagnostics. The vibrational temperatures were determined from vibrational intensity distributions of the second positive system bands (the C³Πu→B³∏g emissions, Δv=-2) in N₂ spectra. These vibrational distribution of the spectrum system have also been adjusted in the present calculations so as to fit experimental spectral intensity and theoretical spectral intensity which depend on rotational temperature and gas pressure. From this diagnosis, the errors associated with the measured vibrational temperature are estimated to be of the order of 6%. However, the present developed diagnosis has also been applied to measure the vibrational temperatures of a negative glow region with the discharge current density on DC-glow discharge plasma in N₂ gas.

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Recentry, the neccessity of establishing the way to diagnose the aging of insulation materials and to prediction of insulation breakdown become important.
In this paper, the prediction of breakdown is considered. A cylindlical void which is made of polyethylene is used for experiments. And the distribution of the discharge magnitude in relation to phase angle of applied voltage is measured by a partial discharge measuring system.
The discharge measurements, such as the discharge magnitude Q, number of pulses N, average discharge magnitude Q_AV, the skweness and the kurtosis are calculated from the distribution to estimate the time to breakdown. In the early stage of aging. life (time to breakdown) can be estimated by regression line which shows the relation between the life and the discharge measurement.
And the new parameters G and C are proposed for the prediction of breakdown and are examined their effectiveness for prevention. G-parameter is the center of gravity and C-parameter is the gradient of the discharge distrbution. They symbolize the portent of the breakdown. It is confirmed that these two parameters are efficient to predict the breakdown just before the breakdown occured.

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Electrical cables in nuclear power generating stations are demanded to have a high reliability. For further improvement of the reliability, the development of nondestructive diagnoses seems desirable for maintenance of cables. The authors have been studying the residual voltage for developing a diagnosis of electrical cables. The purpose of this paper is to give a foundation for development of diagnostic technology for detecting the irradiated degradation; we studied the relations between γ-irradiation dose and the leakage current, the discharge current, and the residual voltage. We have tried to calculate the amount of. polarized charge and characteristic dielectric relaxation time for distribution of relaxation times by using data on the residual voltage. The calculated results agreed with the results obtained from the leakage current and the discharge current. These results suggest that we can employ the residual voltage in diagnostic technology for detecting the irradiated degradation.

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When an AC voltage is applied to a low density polyethylene (LDPE) film placed under a needle-plane electrode system, there is a possibility of the formation of the space charge field in the vicinity of the needle electrode by electrons (or holes) injected from the needle electrode. In the present paper, we investigated the properties of the space charge, e. g., total amount of trapped charge, formed in the vicinity of the needle electrode by using electrical measurements of thermally stimulated current (TSC) and thermally stimulated surface potential (TSSP). From the investigation, it was concluded that a space charge field is formed in an LDPE film by the application of the AC voltage, and that total amount of trapped charge by the application of the AC voltage is less than that by the application of the DC voltage, etc. Finally, on the basis of the present experimental results, we studied the space charge effect on the AC treeing mechanism.

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Scattering and radiation from a system of arbitrary shaped three dimensional conducting wire and body are investigated by the moment method. The wire and body scatterers are treated by the electric field integral equation, triangular shape expansion/testing functions through an identical process. A new technique is presented for treating the wire-body junction problem. The wire at the junction, from view point of the body, is presented by an equivalent triangular patch. Therefore the wire-body junction problem is changed to surface-surface junction problem and the surface junction is treated by overlapping method. In this technique the junction can be at any edge or very near to vertex and also no special attachment-mode is necessary. The moment method formulas are more simple and flexible than the attachment-mode technique. Computed input impedances or admittances are compared with measured or computed data of other authors and very good accuracy is obtained.

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Recently, in order to print patterns of ultra large scale integrated circuits, the demand for soft X-ray sources has become greater. A high current vacuum spark has a merit of flexibility in selection of characteristic X-ray emission wavelengths, because many materials can be used. This paper proposes use of sulfur as an X-ray material from the viewpoint of pattern contrast. Sulfur characteristic X-rays (0.4-0.52nm) offer a range of suitable soft X-rays for various mask materials, i. e. tantalum, tungsten, platinum and gold. In experiments, sulfur was put in a PTFE pipe which was set in the center of the anode. Soft X-ray emissions resulted when a pulse current of about 150kA flowed. The X-ray emission time from discharge to production of a magnetic pinch was about 1μs at various discharge currents. This time was short in comparison with the 2.4μs rise time of the discharge current. Therefore the X-ray intensity should be enhanced by utilizing a fast rise time current.

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Superfluid helium is considered as an excellent coolant for superconducting magnets because it has an apparent thermal conductivity about 1, 000 times greater than copper.
It is widely well known that the behavior of superfluid helium is described by a two-fluid model. For example, when a thermal disturbance occurs, the normal fluid component is aliented from the heat source and the superfluid component approaches the heat source. The superfluid component has a nil entropy, only the normal fluid component will contribute the heat transport. So it is very important to know the velocity of the normal fluid component of superfluid helium.
We have developed a new flowmeter with the objective of measuring the normal fluid component' s flow velocity using ions because ions are valuable probes in the study of superfluid helium. It has a construction in which two set of electrodes are fitted inside a glass tube. The fluid is flowed inside this glass tube, and 10kV is impressed on the electrode of the upper stream generates a discharge phenomenon by which a part of the fluid is ionized. A voltage of 5-8kV is impressed on the electrode on the downstream side. In this condition, no discharge will be generated, but a discharge is triggered when the fluid ionized upstream flows down. The fluid's flow velocity is calculated from the difference in the time which these two discharge phenomena are generated. This flowmeter is available for all other kind of fluid except inflammable or explosive fluid.
In this paper this flowmeter has been tested for nitrogen gas and liquid nitrogen and proved to work well. We have also succeeded in measuring the flow velocity of the normal fluid component.

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The initiation and growth of electrical tree in crystalline polymers are influenced by the superstructure. But, there are still many unclear points in the relationship between the tree deterioration and the superstructure (spherulites).
In order to study relationship between the tree deterioration and the spherulite, we designed the measuring apparatus which allows simultaneous observation of these phenomena. The sample was set on the stage of the polarizing microscope to make observations of the tree initiation and growth in polypropylene.
This paper reports results of some observation concerning the tree initiation and growth in polypropylene with 60Hz AC voltage. The results are as follows:
(1) Prior to the initiation of trees, a fine deterioration zone is formed on spherulite surfaces. Thereafter, the discharge is occurred along spherulite surface, and the trees occur.
(2) Tree shapes change under the influence of distribution state of spherulite.
(3) Tree initiation voltage are 5.8kV for the spherulite inside and 5.1kV for the spherulite boundary, respectively.

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