Effects of Some Additionals for the Magnetic Properties of Ba and Sr Oxide Magnets

Technical magnetic properties of Ba and Sr oxide magnets were measured with various amounts of additionals. It has been found that SiO_2, B_2O_3, GeO_2 and Cr_2O_3 are fairly effective, but CdO, SnO, CoO and CuO are not effective and V_2O_5 is very injurious. The improved properties of the isotropic ferrite magnet with these additionals are, for instance, 2500 Gauss in remanence and 1700 Oersted in coercive force and 1.5×10^6 Gauss Oersted in BH_. Curie points of Ba and Sr ferrite are 450℃ and 475℃ respectively and they are not changed by 3 per cent or so of these additionals. Effect of magnetic annealing could not be observed in the system. dI/dT is 0.6～0.4 Gauss/degree and no additional has been found to decrease dI/dT without the decrease of I_3 in the scope of the work

初婚過程の規定要因 : 兄弟姉妹構成の影響を中心に

This study attempts to clarify the effects of sib size, birth order and the possession of older brothers, older sisters, younger brothers, or younger sisters on first marriage formation in Japan. Twelve sociological demographic and psychological hypotheses are presented and examined with regard to their effects on three outcomes in each age segment: getting married through arranged marriage, getting married through love marriage and staying never-married.P. Allison\u27s discrete-time event-history analysis (using multinomial logit model) is applied to the merged data of never-married and first-married persons aged 18-34 from the 1982 national fertility survey conducted by the Institute of Population Problems in order to simultaneously examine the effects of sibling configuration on both the timing and the two mate selection methods of first marriage (first marriage probability by mate variables with another set, age, and prenuptial living arrangements. The results seem to support the Parental Control Hypothesis and the Acquaintance Opportunity Hypothesis for both sexes and the Normative Order Hypothesis for females. Other hypotheses including the Household Crowding Hypotheses and the Demand for Children Hypothesis also seem to have limited support

The Asuka-87 and Asuka-88 collections of Antarctic meteorites: Search, discoveries, initial processing, and preliminary identification and classification

Over 2400 pieces were collected by the Asuka wintering party of the 29th Japanese Antarctic Research Expedition (JARE-29,1987-89) on the bare icefields around the S∅r Rondane Mountains in Queen Maud Land, East Antarctica. The Asuka party searched almost all of the bare icefields around the mountains in the 1987-88 and 1988-89 field seasons. About 110 pieces (Asuka-87) of meteorites were collected on the bare ice around Mt. Balchen in the eastern part of the mountains in January and February 1988. In the first reconnaissance, about 240 pieces of meteorites (also Asuka-87) were recovered from the Nansenisen Icefield in February and March 1988. The Asuka-88 meteorites, over 2100 pieces, were found during the systematic search of this icefield during November 1988 and January 1989. The specimens were named officially the Asuka (A)-87001 to A-87352,and A-880001 to A-882124,in order of discovery. The Asuka-87 and Asuka-88 meteorite collections were filed as the National Institute of Polar Research (NIPR) meteorites with details of date of find, weight, dimensions and comments. According to the initial processing, the Asuka-87 meteorites comprise one iron, one stony-iron, 9 achondrites, 3 carbonaceous chondrites and over 300 ordinary chondrites, the total weight being 120kg. The largest specimen in the Asuka-87 collections is an LL-group chondrite of about 46kg. The Asuka-88 meteorites comprise 7 irons, 5 stony-irons, over 50 achondrites, 31 carbonaceous chondrites and over 2000 ordinary chondirtes. The total weight is about 400kg. Two specimens in the Asuka-88 collection were tentatively identified as a very coarse-grained and unbrecciated gabbroic meteorite and an olivine-fassaite-plagioclase achondrite with crystalline texture

Meteorite search by JARE-39 in 1998-99 season

A meteorite search party composed of eight men of the 39th Japanese Antarctic Research Expedition (JARE) collected 4136 meteorites on bare ice areas around the Yamato Mountains and the Belgica Mountains in 1998-99 field season. Approximately 4100 meteorites have been collected around the Yamato Mountains. They include many kinds of rare meteorites. By classification in the field, 2 lunar meteorites, 3 irons, 4 stony irons, 15 ureilites, 37 diogenites, 63 eucrites, 29 unclassified achondrites and 160 carbonaceous chondrites are distinguished. The number of irons is very small for such a great number of the meteorites. We also searched for meteorites around the Belgica Mountains. Twenty-one meteorites have been collected. All of them are ordinary chondrites

On the Condition of Synthesis for Fe(CO)_5

The suitable condition of synthesis for Fe(CO)_5 was determined by the chemical data of equilibrium state and also discussed qualitatively from the view point of the reaction velocity. The results were checked by some experimental data and it was found that the results were good enough to guess the suitable condition

Studies on the Oxide Magnets. III : Effects of TiO_2

The relationship between magnetic properties and the amount of TiO_2 was observed on TiO_2-Fe_2O_3-MO system (M=Ba, Sr and Pb) in the range (Fe_2O_3 + TiO_2)/MO = 4～9. Specimens were prepared from TiO_2, oxides or carbonates of M and Fe_2O_3 Obtained from Fe(CO)_5. Magnetic properties were weakend by the addition of TiO_2, except at the ratio of (Fe_2O_3 + TiO_2)/MO=4, and it is considered that the apparent improvement at this composition may be due to the shift of the maximum point of magnetic properties in Fe_2O_3-MO system

On the Magnetic Property of Iron Oxides

Pure α-Fe_2O_3 powder prepared by oxidation of Fe(CO)_5, was reduced to Fe_3O_4 by the hydrogen stream containing water vapour. The magnetic properties were measured at each state of reduction and the reduced grade was checked by the chemical and X-ray analysis. Fe_3O_4 thus prepared, was oxidized again and it was proved that the changes of the magnetic properties during oxidation and reduction, coincide with one another

Studies on the Oxide Magnets. IV : Effects of Al_2O_3

The relation between magnetic properties and the amount of Al_2O_3 was observed in Al_2O_3-Fe_2O_3-MO system (M=Ba, Sr and Pb), varying the ratio of (Fe_2O_3+ Al_2O_3)/MO from 3.5 to 6.5. In order to obtain a constant and good activity, Fe_2O_3 specially prepared from Fe(CO)_5 Was used. Coercive force of these magnets increased through the addition of Al_2O_3 but saturation or remanent decreased with the amount of Al_2O_3, except at the composition of (Al_2O_3+Fe_2O_3)/BaO<4.5

Effects of Additionals on the Magnetic Properties of PbO-Fe_2O_3 System

Effects of additionals on the magnetic properties were observed in PbO-Fe_2O_3-MO system, varying the sintering conditions and the value of Fe_2O_3/PbO. Substituting PbO or Fe_2O_3 for SnO, ZnO, CdO, MgO, NiO, CuO, CoO, Cr_2O_3, B_2O_3, GeO_2, SiO_2 and ZrO_2, etc., it was found that Cr_2O_3, B_2O_3, GeO_2 and SiO_2 are effective. Best results were obtained in these systems mixed at Fe_2O_3/PbO=4～5 by mol and sintered at 950°～1100℃. Magnetic properties of the improved PbO system oxide magnets were comparable to those of the BaO or SrO system