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1.
J. M. Parpia W. P. Kirk P. S. Kobiela Z. Olejniczak 《Journal of Low Temperature Physics》1985,60(1-2):57-72
The ac susceptibility of lanthanum-diluted cerium magnesium nitrate has been compared to the temperature scales as derived
from the (P, T) relation determined by Halperin and that was measured recently by Greywall. It is found that the susceptibility does
not obey a simple Curie-Weiss law over the temperature range between 1 and 50 mK. The results of these calibrations are also
used to determine the temperatures for the second-order phase transitions into the superfluid phases of3He at several pressures. TheseT
c(P) values are compared to results of earlier experiments that used thermometry based on the susceptibility of platinum as well
as other thermometry techniques. 相似文献
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Scale and sludge from Bulalo geothermal field, Philippines, have been characterized by whole rock analysis, radioactivity counting, size analysis, light microscopy, scanning electron microscopy, and X-ray diffraction. Their leachability was assessed by regulatory leaching procedures and by sequential extraction. Both scale and sludge consisted mostly of oxides of Si, Al, and Fe with no radionuclides detected. The scale had 10% S content. Sulfides and silicates were important phases in both samples having size ranges from submicron to 2 mm. Geothermal soils at Bulalo have higher than normal soil levels of As, S, Cu, Cr, Zn, and Pb but regulatory leaching tests indicated that these elements are not released. However, the sequential extraction showed that As, Cu, and Zn were leachable under extreme conditions. 相似文献
5.
The crystallization behaviour of three amorphous alloys, Co50Ni25Si15B10, Ni50Co25Si15B10 and Ni50Co25P15B10, was studied by means of differential thermal analysis in conjunction with scanning transmission electron microscopy. Isochronal annealing showed a strong dependence of crystallization on scan rate over the range of 1.99 to 20.70 K min–1. At high Co/Ni ratios, a sequential two-stage crystallization process involving primary MS-I phase followed by MS-II phase precipitation was observed. At low Co/Ni ratios MS-I and MS-II crystallization were concurrent and inseparable. Replacement of the metalloid Si with P as the glass-former dramatically reduced the activation energy for crystallization as well as the crystallization temperature. A mechanistic understanding of these findings was pursued in light of TEM/STEM microanalysis 相似文献
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In Clione limacina, locomotory rhythm is produced in the central pattern generator by reciprocal activity of two groups of interneurons. Dorsal (D) and ventral (V) phase interneurons activate neurons of the same phase and inhibit neurons of the opposite phase. Which neurotransmitters are used by these interneurons is not clear. In this study, identified follower neurons to V and D interneurons were isolated, and their responses to the local application of potential neurotransmitters were examined. Acetylcholine exerted inhibitory action on the isolated D-phase neurons and excitatory action on V-phase neurons. Glutamate produced excitation in D-phase neurons, and inhibition in V-phase neurons. These results suggest that acetylcholine is the neurotransmitter of D-phase interneurons, while glutamate might be the neurotransmitter of V-phase interneurons. 相似文献
8.
Douglas H. Taylor Kirk E. Lagory Daniel J. Zaccaro Ronald J. Pfohl R.Dana Laurie 《The Science of the total environment》1985
Trichloroethylene (TCE) is a common contaminant of underground water supplies. To examine the effect of TCE on the developing central nervous system, rats were exposed to TCE throughout gestation until 21 days postpartum via their dams' drinking water. TCE concentrations of 312 mg/l, 625 mg/l and 1250 mg/l were tested. Exploratory behavior was higher in 60- and 90-day old male rats which were exposed to any level of TCE. The effect of TCE-exposure on locomotor activity (running wheel) was also examined in 60-day old males (625 and 1250 ppm exposure groups). Locomotor activity was significantly higher in rats exposed to 1250 ppm TCE. These data suggest that TCE has long-term effects on behaviour. 相似文献
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The formation of zinc ferrite (ZnFe2O4) during the roasting of iron-bearing zinc concentrates requires substantial additional processing to recover the zinc from
this compound by leaching and to eliminate the iron from the leachate. The phase changes that occur in the particles of a
typical industrial zinc sulfide concentrate during roasting in a fluidized bed at 1223 K were investigated by the use of light
microscopy, electron microprobe analysis, and SEM with EDS. The processes which the iron undergoes during its eventual transformation
into ferrite have been clarified by examination of the phases and the morphology of partially roasted marmatitic sphalerite
particles (Zn, Fe)S, and by reference to the known phase equilibria involved in the Zn-Fe-S-0 system. The oxidation of ironbearing
sphalerite occurs in three stages. The first involves the selective diffusion of most of the iron to the particle surface
resulting in the formation of an iron oxide shell enclosing a largely unreacted zinc sulfide kernel. In the second stage,
this kernel is oxidized to form a solid solution of zinc oxide and iron oxide. The iron is initially present in the ferrous
state but, with the disappearance of the sulfide kernel, is oxidized to ferric iron. In the final stage, this dissolved iron
oxide and the iron oxide shell react with the surrounding zinc oxide to form the refractory spinel zinc ferrite. 相似文献