巻号一覧
32 巻, 6 号
選択された号の論文の5件中1～5を表示しています
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V. A. TROITSKAYA, O. V. BOLSHAKOVA, E. T. MATVEEVA1980 年 32 巻 6 号 p. 309-324
発行日: 1980年
公開日: 2010/03/12
ジャーナル フリーProperties of polar cap pulsations of discrete type occurring sporadically (IPRP, Pc 1b) and regularly observed around noon (ipcl, Pc 1-2) are described. The character of their dependence on Kp, their diurnal variation, and other morphological properties are used to determine the position of the dayside cusp, and the dynamics of its shifting on latitude. Recent observations of parameters of the regions of the outer magnetosphere are used for suggestions of possible mechanisms of generation of these pulsations. Briefly are outlined the characters of behaviour in the polar cap of well known pulsations of Pc 3, Pc 4, and Pi 2 types.抄録全体を表示PDF形式でダウンロード (2588K) -
Liana F. ZAMBRESKY, Tomiya WATANABE1980 年 32 巻 6 号 p. 325-331
発行日: 1980年
公開日: 2010/03/12
ジャーナル フリーA magnetic sensor coil is shown to behave as a 2nd order Butterworth low pass filter for induced e. m. f. if the coil's output ends are terminated with a set of parallel resistor and capacitor matched to the sensor. The conditions for matching are theoretically derived, assuming an equivalent circuit of the sensor coil. An experiment to check the Butterworth filter behavior agrees well with the theory. It demonstrates the validity of the assumed equivalent circuit of the sensor. The corner frequency of the filter can be changed, selecting different matched values of the resistor and capacitor. In the experiment, the corner frequency is set at 6Hz which rejects 60Hz man-made noise 40 db ca. without distorting magnetic pulsation signals up to the highest frequency range (Pc 1). This technique for rejection of man-made noise is more advantageous than another common practice, putting a twin-T filter between the sensor and the head amplifier. A twin-T filter used this way is shown to give rise to ringing depending on the characteristics of the sensor, the twin-T filter and the input impedance of the head amplifier.抄録全体を表示PDF形式でダウンロード (620K) -
N. S. SASTRI, B. N. BHARGAVA1980 年 32 巻 6 号 p. 333-340
発行日: 1980年
公開日: 2010/03/12
ジャーナル フリーVariation of the additional magnetic field due to the counter-electrojet is examined over the latitudes from the dip equator to Sabhawala (dip=45°) separately for January and the summer months. The additional field is derived from a set of days on which intense afternoon counter-electrojet events have been recorded at Trivandrum near the dip equator, during the period 1965-1977. An almost a reversal in the pattern of field variation in declination is observed between January and summer at all the stations. An approximate representation of the overhead current vectors during the daytime hours in summer months, under the assumption that the field effects result from an additional current system, suggests a vortex in the afternoon with a clockwise rotation and an oppositely directed vortex in the forenoon.抄録全体を表示PDF形式でダウンロード (676K) -
P. TUCKER, W. O'REILLY1980 年 32 巻 6 号 p. 341-355
発行日: 1980年
公開日: 2010/03/12
ジャーナル フリーSynthetic single crystals of titanomagnetite (Fe2.4T0.6O4) were progressively oxidized at 1, 275°C, under controlled CO/CO2 atmospheres to simulate the “deuteric oxidation” process which occurs in nature. For moderate degrees of oxidation the resultant phase assemblage comprised two titanomagnetite phases intergrown with hemoilmenite lamellae. During the acquisition of weak-field thermoremanent magnetization (TRM) by the oxidized multiphase samples, the direction of magnetization was found in some cases to be opposite to that of the applied magnetic field. This self-reversal is thought to be due to a negative magnetostatic interaction between the two titanomagnetites. The interaction field was estimated as being of the order of a few hundred Amps per metre and is thought to be magnetostatic in origin. The region of self-reversal was confined to a narrow oxidation range although partial self-reversal was observed over a much wider range.抄録全体を表示PDF形式でダウンロード (3283K) -
Leroy R. ALLDREDGE1980 年 32 巻 6 号 p. 357-364
発行日: 1980年
公開日: 2010/03/12
ジャーナル フリーPDF形式でダウンロード (623K)
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