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91.
Osami Yanagisawa Mitsuru Izumi Wei-Zhi Hu Kenji Nakanishi Hideo Nojima 《Journal of Superconductivity》1999,12(1):307-310
The magnetic behavior of the distorted perovskite manganese, Pr0.65Ca0.35MnO3 was studied by X-band electron spin resonance for powder samples. We observed the onset of the charge-ordered state at T
CO215 K, the antiferromagnetic transition with the peak of the ESR linewidth, H
p–p
at T
AF180 K and the canted antiferromagnetic transition at T
CAF125 K associated with the abrupt increase of both the effective magnetization and H
p–p
. Below 90 K, the absorption intensity profile becomes weakened with decreasing temperature suggesting the existence of some kind of magnetic disorder below 90 K, which is responsible for a part of evidence of the existence of the spin-glass state as has been proposed by Yoshizawa et al., Phys. Rev. B
52, 1689 (1996). 相似文献
92.
Yasunari Nagaki Satoru Itabashi Hideo Mitsui Mototaka Sone 《Electrical Engineering in Japan》1994,114(3):23-32
It has been proposed that vapor-mist dielectrics in which mixing liquid droplets such as tetrachloroethlene in a gas have the ability of increasing flashover, impulse voltage, and of suppressing partial discharge. Vapor-mist methods have been performed on other materials and the effect of the mist can also be obtained on benzene, hexane, and even water as general materials. Although these studies have been carried out, neither the discharge mechanism on vapor-mist nor the reason for the increase of the discharge voltage is understood fully because the mist is of various sizes. On the other hand, agglomeration of water molecules can be studied with the FR-IR method, and are classified into monomer, dimer, trimer (including polymer). Water gives mist stats which are significant in discussing effects. This paper describes states of water mist and their effect under nonuniform field with positive and negative polarities. Water mist in vapor exists as dimer and trimer, and their amount decreases with the reduction of temperature. These mists have no effect on discharge suppression. However, when the mists are formed by space charges, the inception voltage is increased by these mists in the negative polarity. 相似文献
93.
Takeshi Naito Hideo Ueda Masao Kikuchi 《Metallurgical and Materials Transactions A》1984,15(7):1431-1436
The characteristic fatigue behavior of carburized and quenched steel with internal oxides and non-martensitic microstructure near the surface was presented through rotating bending fatigue test. The S-N diagram revealed two knees and the specimens continued to fail over 107 stress cycles. The fatigue limit could not be obtained even at 108 stress cycles. The test results were compared to those for the specimens without surface structure anomalies to show the effect of structure anomalies on the fatigue behavior of carburized steel. 相似文献
94.
S. Nakagawa M. Kuno Y. Naito T. Nozawa T. Momma J. Mizuno T. Tsukamoto S. Motohashi M. Niwa 《Nuclear Engineering and Design》1998,179(2):145-156
Forced vibration tests were carried out at the Hamaoka (BWR) Unit 4 R/B (reactor building) in Japan in April and May of 1992. Fundamental dynamic characteristics of the R/B were obtained, including its interaction with the adjacent T/B (turbine building) and the soil–structure interaction. Results for the preceding R/Bs are compared, and probable causes for fluctuations in the resonance curve around the 1st peak are discussed. Furthermore, simulation analyses of the fundamental dynamic characteristics of the soil–structure system were conducted, using a basic lumped-mass soil–structure model (lattice model), and strong correlation with the measured data was obtained. Other detailed simulation models were employed to investigate the effects of simultaneously induced vertical response and response of the adjacent turbine building on the lateral response of the reactor building. 相似文献
95.
Brittle material fractures at a critical value of stress intensity factor or crack opening displacement (COD) without any prior crack growth. In the ductile materials, however unstable fracture initiation may be preceded by a period of slow crack growth from the notch tip. Such slow crack growth may be an essential prelude to unstable fast fracture and thus COD at the start of slow crack growth can also be regarded as a critical value of the fracture characteristics. We have tried to apply the acoustic emission techniques to the COD test. Acoustic emission techniques can be used to detect the onset of slow crack growth and to obtain a relation between COD and AE characteristics in the COD test. 相似文献
96.
Crack propagation velocity in delayed failure under superposed repeating load, (, was compared with that under static load, (Two peaks appear on the relation between decreasing rate of crack propagation velocity, and frequency, ?, both under sinusoidal and square load. By changing the ratio of holding time at maximum stress intensity factor to that at minimum stress intensity factor in square load, it was deduced that the existence of two peaks on the 1 ? β vs curve was caused by an asymmetric interaction between hydrogen atoms and cyclic moving of the position with triaxial tensile stress at crack tip. Moreover, the relation between 1 ? β and under the positive or negative saw tooth load could be well explained by the interaction model. 相似文献
97.
The mechanical properties of Fe-13 wt% Cr-2 wt% Mo-2.5 wt% Ti alloy were examined by tensile tests with respect to its fracture mechanism. In order to improve the properties, 1 wt% Nb was added and its effects were examined. In the temperature range, room temperature to 500° C, the fracture characteristics of the alloys are mainly governed by the characteristics of the x-phase precipitation. Fracture elongation is a function of (C/r)1/2 where C is the radius of the x-phase and r is its mean spacing. 1 wt% Nb addition is an effective method for improving the ductility without a decrease in the strength of the alloy. 相似文献
98.
The method has been developed to improve the bitumen product which incorporates an evaporator concentrate from a BWR, with respect to the swelling and leaching. The leachability of the product has been measured by the method recommended by the IAEA. The swelling of the product is successfully prevented by the addition of calcium chloride. The specimen containing the waste up to Wa/B (Weight ratio of Na2SO4 + CaCl2 and bitumen) = 60:40 shows no pronounced swelling, when it is immersed in water. The cumulative fractions of 137Cs and 60Co leached from a specimen which does not contain CaCl2 are 0.65 and 0.2 at the leaching time of 30 days. On the hand, the corresponding value at 100 days for the specimen with calcium chloride addition is 5 × 10?4 for 137Cs and 1 × 10?4 for 60Co. The coating of the specimen surface with a fresh bitumen (5 mm thickness) reduces the leachability further. These results indicate that this method is effective to improve the bitumen product incorporating BWR's evaporator concentrate. 相似文献
99.
Kichizo Niwa Goro Shimaoka 《JOM Journal of the Minerals, Metals and Materials Society》1957,9(4):430-434
Single graphite flakes segregated from molten carbon or silicon-rich iron at 1200° to 1500°C were subjected to electron diffraction experiments. The results indicated that the well developed thick flakes are composed of one single crystal, while the thin almost colorless flakes consist of two or three single crystals oriented with the basal plane parallel to the flake surface and rotated at an angle of 15°, 18°, 22°, 25° or 28° about the C-axis. The stacking of the atomic layers in each single crystal indicates that they are α and β-type, or a more disordered structure, at each instant. Double diffraction evidence and additional electron microdiffraction observations showed that the thin single flake has an aggregate structure with two close-packed single crystals. 相似文献
100.