We have carried out the experiments on TEA-CO₂ laser oscillation using the inductive energy storage pulsed-power generator, which has an copper wire fuse as an opening switch. Maximum laser output energy of about 1J/pulse was obtained in case of fuse length of 5cm and energy storage inductance of 8μH. The laser output energy depends on the energy storage inductance and the parameters of the fuse. In this paper, the dependencies of laser output energy on inductance and fuse length, and the comparison between the inductive and capacitive system were described. Furthermore the laser efficiency was discussed by calculating the electron energy distribution of laser main discharge region.

抄録全体を表示

The escape factor of a resonance radiation, which have Voigt profile and emitted by resonance atoms distributed in parabolically in a infinite cylindrical discharge tube, was calculated. In the case of complete redistribution in frequency, the escape factor was calculated precisely by numerical method, and the Walsh's formula agree with precise numerical result within 10 percent. In the case of partial redistribution in frequency, the author derived a new formula of escape factor similar to the Walsh's formula from the spectrum given by Post. This new formula agree well with Payne's result for argon gas which was derived by transport equation of photons. The new formula also be able to improve the discrepancy between theory and experiment appear in the study of Ferreira and Loureiro.

抄録全体を表示

In this paper, we studied the wave propagation and reflection on the linear ladder type circuit. Several examples of the exact linear response of this circuit were found. And the band pass ladder type circuit has a peculiar property with respect to the wave propagation.It is possible that the phase and group velocities of the wave on this circuit have opposite direction each other. Moreover, the wave reflection on the ladder type circuit was considered.
Reflection and transmission coefficiency of the wave were calculated, and non-reflection condition was found. From this condition, the non-reflection terminal circuit was constructed.

抄録全体を表示

Proximity resistance to high-frequency current conducted with same direction in contact has been analyzed, taking Lorentz and Coulomb forces into considerations.
As a result, displacement of conducting carriers caused by the proximity effect, forms the new current distribution with three components, that is, skin effect, Lorentz force and Coulomb force components without the boundaries of carriers.
Based on this consideration, the ratio of ac resistance to the dc one has been calculated, using Cassinian ovals. The calculated resistance was in agreement with experimental value within 10%.

抄録全体を表示

Internal space charge behavior of an insulating material has been widely discussed recently, and many experiments were carried out by using the materials for dc cables, such as XLPE, LDPE and HDPE. Since epoxy resin is used for insulation under strong electric fields in power apparatus and in electronic devices, we used the pulsed electroacoustic method to investigate the internal space charge behavior of epoxy resin samples: two types used for insulation and one type for craft use.
When dc electric fields were applied to the craft resins treated by immersing them into R.T. water for 8hrs and 24hrs, positive and negative charges accumulated near the anode and the cathode respectively, and the charge distributions changed with the immersion time. On the other hand, no charge was observed in the insulation type. Then we treated the samples by immersing them into 100°C water for 8hrs. When the sample was treated fbr 8hrs, hetero charge dlstribution which means the positive charge near the cathode and the negative charge near the anode, were observed. This result is consistent with a previous paper reporting that chemical analysis revealed that the secondary decomposition occurred. These results show that water and temperature influence on the internal space charge behavior of epoxy resins.

抄録全体を表示

Composite materials like carbon fiber reinforced plastics (CFRP) or fiber reinforced plastics (FRP) are used for construction materials of spacecraft. In case fiber reinforced plastics (FRP) are used for construction materials of spacecraft, germanium (Ge) sputtered FRP is used because of its ability of thermal control. On an orbit of high altitude, the charging on polymer materials can cause troubles in measurements on spacecraft.
To investigate the charging phenomena on these kinds of materials in vacuum, electron beams are irradiated on test pieces of FRP, Ge-sputtered FRP and CFRP. The experiments are conducted in a high-vacuum chamber attached with an electron beam gun.
The results show that the absolute values of the surface potential of Ge-sputtered FRP keep lower values than that of FRP. The irradiation on negatively charged Ge-sputtered FRP decreases the magnitude of the surface potential. Ge-sputtered FRP with a thicker layer of Ge shows a similar and pronounced tendency. Irradiation with higher current density also causes more rapid decrease of the potential. The results for CFRP also show low values of the saturated surface potential. These characteristics are different from those of simple polymer test pieces such as a fluoroethylenepropylene (FEP) film. In spite that the penetration depth of electrons is confined in Ge layer, the surface potential of Ge-sputtered FRP shows lower values than the potential expected for single materials. The mechanism of this phenomenon seems to be related to secondary electron emission.

抄録全体を表示

A magnetically shielded room (MSR) is constructed by combing superconducting panels with normal conductive junctions. The MSR is composed by vacuum insulation panels, a tank for liquid nitrogen for superconducting panels and a ferromagnetic door. Thermally insulating vacuum panels, a reservoir of liquid. nitrogen to cool the superconducting panels and ferromagnetic door make up the MSR.
The superconducting panel is made of 0.2mm thick Bi₂Sr₂CaCu₂Ox film coated on both side of a silver sheet (600mm×800mm× 0.5mm). The MSR are constructed by connecting panels by soldering on the edge of the silver sheet 50mm in width. Measurement results of shielding factors of MSR to ac magnetic fields did not agree with a simple computation supposing that the MSR is shielded by superconductors with perfect connection. We developed an equation to compute the shielding factors taking account of leakage magnetic fields through the normal conductive junction. The computation fundamentally agreed with the measurement results so that the equation is applicable to evaluate a shielding performance of a superconducting MSR.
As well known, a double layer permalloy MSR must keep a fair distance between the two layers to keep effective shielding factors of each layer. A double layer MSR composed of a ferromagnetic shield layer and a superconducting layer gives the best shielding factor when the distance is zero and the factor exceeds multiplication of factors of each layer. We demonstrated the distance effect by experiments.

抄録全体を表示

Localized flux waveforms in laminated core are usually measured by using a search-coil method. However, this method has several problems due to holes for search coils, such as measurement error of magnetic field strength due to deterioration of magnetic properties in and around hole, and restrictions of distance between holes and number of measuring positions. In order to overcome those difficulties, a stylus-probe method and an improved probe method have been developed. Although these methods enable us to measure localized flux waveforms in a single sheet, they are not applicable to the laminated core because of insufficient interlaminar gap for setting probes and necessity for setting probes at corresponding positions on both sides of all sheets in the laminated core. In this paper, a new nondestructive method called a "B-estimated method" for evaluating localized flux waveforms in the laminated core is proposed. The effectiveness of the newly proposed method is validated by measuring waveforms of flux density and magnetic field strength, and by calculating iron losses from those waveforms at several positions in a model transformer.

抄録全体を表示

Up to now, a bulk and a thick film as a temperature-sensitive substance has been provided. However, the sensitivity of these substances with a large heat capacity are low level for minute temperature detection. The development of a thin film following the tendency of a miniaturization and lightweight of an electronic system has been required. The preparation of a temperature-sensitive magnetic thin film (TMF) has not yet been proposed because the adjustment of the mixture ratio on the TMF's materials which are metal oxides of Fe, Mn and Zn is very difficult. Then, the authors investigated a method fabricating the TMF via an annealing treatment after the sputtering of a temperature-sensitive ferrite with low Curie temperature as a target. The method has two step profile that after depositing metal components of a temperature-sensitive ferrite on the substrate by sputtering, a high temperature annealing treatment is performed pouring argon gas in a tank including oxygen, as result a ferrite thin film (thickness: 1.5μm) with spinel structure can be prepared. The TMF reproduced faithfully a component of a temperature-sensitive ferrite has the remarkable temperature dependence and a small heat capacity, so responds sharply to a minute temperature variation of 10^-1°C degree. There fore, the TMF is expected to be applied to a pyromagnetic sensor, an optimized artificial sensor as well as a biosensor.

抄録全体を表示

The Pulsed Electro-Acoustic (PEA) method has been used for the measurement of space charge distribution in coaxial cables. When the PEA method are applied to the measurements of cables with various radius, however, it is necessary to make the curved surface electrode which fit with each outer radius of various cables. Therefore, we attempt to develop the PEA system with a flat electrode instead of curved surface electrode. To develop the new system, an analysis of optimum size of piezoelectric sensor is carried out, Furthermore, a structural improvement is adopted to reduce a noise level. Using the newly developed system, the PEA method become to be applicable to the any kind of cables with various radius.

抄録全体を表示

We have evaluated the electrical degradation of the Zincoxide(ZnO) varistors added two kinds of additives by the V-I measurements and the improved ICTS method. Results of the V-I characteristics show that both the characteristics of varistors added Bi₂O₃ and CoO and those added Bi₂O₃ and MnO₂ were recovered by thermal annealing. This indicates that the distribution of O₂- ion changed by applying voltage was returned to the initial condition by thermal annealing. Results of the improved ICTS measurement show that the trap density for varistors added Bi₂O₃ and CoO decreased after degradation. Trap levels for varistors added Bi₂O₃ and MnO₂ became shallower after degradation. The result of simulation shows that varistors with narrow distribution of trap levels, deep trap levels and the low donor density have excellent nonlinear characteristic.

抄録全体を表示

In the magnetic circuits under the demagnetizing field condition the fluxes of permanent magnets decrease gradually with the operating time. The loss of the flux is irreversible and affected by the magnetic properties, the temperature and the dimensional condition of the magnetic circuit. This paper proposes a new method for estimating the flux loss of rare-earth magnets for the application required the long-time stability. The non-dimensional value Δ=μr•HCJ/B_r-(1-B/B_r), the 1st term is decided by the magnetic properties at the operating temperature and the 2nd term is decided by the condition of the magnetic circuit, can be used as the parameter to predict the flux stability. When Δ is greater than 0.2, both of the initial flux loss and the aging loss of the rareearth magnets are shown in a small amount.

抄録全体を表示

The results of the loss measurements of some rare-earth permanent magnets in a. c. magnetic field are presented. The losses are consisted of the eddyurrent losses and the hyteresis losses of the magnets itselves and the eddy-current losses of the metal coatings. The hysteresis losses occur in Sm₂Co₁₇ type ones. These data can be applied for estimating the tooth-ripple losses of the motors with permanent magnets on the pole surfaces, and for discussing the flux loss under the motor flux condition.

抄録全体を表示