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A new study uses transmission electron microscopy and a three-dimensional atom probe to investigate the microstructures of a Nd8Fe76.5Co8B6Nb1Cu0.5 nanocomposite permanent magnet.

To investigate the variations of the solar activity over a long time scale, we have started the measurements of 14C in an ancient tree, synthesizing 10 g benzene from the tree rings and using the liquid scintillation counting system Quantulus with ultra low background level. The background rate of the Quantulus was 1.2 cpm while the counting rate of 14C was 91.0 cpm for the ancient tree. The pulse height distribution of [Beta] rays from inc was well fitted with theoretical [Beta] rays spectrum. The Quantulus detected [Beta] rays down to 7.5 keV with good detection efficiency. It was confirmed that the total counts from the 14C in the sample benzene can be measured within 0.2% accuracy on the basis of the pulse height distribution of a standard benzene sample, using the least squares fitting method.

A new type of proportional counter utilizing a capillary plate with the capability of fine position resolution and high gas gain has been developed. It consists of a bundle of fine glass capillaries with electrodes on both the inlet and the outlet. The capillaries are 100 [[micro]meter] in diameter and 800 [[micro]meter] in length, and gas multiplication was found to occur in each capillary with an applied voltage between the inlet and the outlet. The proportional counter was found to operate up to a gain of [10.sup.4] at gas pressures of 1, 0.75 and 0.5 atm. The energy resolution for 1 atm was 20.8% for 5.9 keV X-rays at a gas gain of 4000. The detection efficiency was comparable to a conventional single wire proportional counter. The dependences of energy resolution on the drift and applied voltage to the capillary plate are investigated and discussed, using calculated electric fields for the drift and capillary regions.

Describes a study which investigated the microstructures of a ... nanocomposite magnet by transmission electron microscopy and three-dimensional atom probe microanalysis. Transmission electron microscopy observations; Atom probe analysis; Microstructural evolution from an amorphous alloy; Results and discussion.

To measure at an accuracy of [is less than] 0.2% the variations of the [sup.14]C concentration in old tree rings, we have constructed a high accurate [sup.14]C measuring system composed of a benzene synthesizer and a Quantulus 1220[TM]. The detection efficiency decreased in proportion to the number of shift channel in the [sup.14]C spectrum due to the quenching effect. The decreasing rate was 0.092% for 1 channel shift. Analysis by ion-chromatography showed that the ion [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] in the benzene sample was a main factor quenching the spectrum. The counting stability of the Quantulus for long term measurement was tested using the synthesized benzene samples for the duration of 5 months. All the data were distributed according to Poisson statistics and were within the Poisson counting precision of 3[[Sigma].sub.p] around the average counts. We conclude that the counting fluctuation of the Quantulus is almost determined by the Poisson counting statistics. Moreover, from the data analysis for the trend of the counting rate, it is indicated that the Quantulus operates with a high stability and has the possibility to detect the systematic variations of the counting rate which are 0.3% in the duration of 5 months.

Abstract: How do product variety and quality affect the aggregate price bias? We develop a general equilibrium model that accounts for the joint interaction of product quality and variety. Our findings show that the aggregate price bias is procyclical and the contribution of product variety is persistent whereas the contribution of product quality becomes countercyclical in the medium to long run. We show that accounting for product quality and variety has critical implications on the measure of cyclical fluctuations. Measurements of cyclical fluctuations derived using the consumption deflator, which abstracts from changes in product quality and variety, underestimate the variables' true volatility. [ABSTRACT FROM AUTHOR]

Magnetic properties of the intergranular phase in the bcc-Fe/NdFeB nanocomposite alloys containing Nb and Co were investigated with Mo¨ssbauer spectroscopy. The alloys were prepared with melt-spinning and post-annealing method. It is revealed that the intergranular phase is not amorphous as considered so far and consists of several thin layers outside the nanoscale grains of bcc-Fe and Nd[sub 2]Fe[sub 14]B. The hyperfine field in the layer on the surface of the grain is rather strong and the structure of this layer is similar to the grain. The field in the outer layers is reduced because the structure becomes indistinct gradually as the layer is apart from the grain. The high remanence and coercive field of the nanocomposite alloys may originate from the magnetic coupling between grains via the intergranular ferromagnetic phase. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The effects of different photoperiod treatments (12, 16, 20, or 24 h) and their duration (1, 2, 3, or 4 weeks) on the percentage of flowering plants and the number of inflorescences were investigated in the Summer in everbearing (EB) strawberry (Fragaria x ananassa Duch.) cultivars with various EB strengths in a field in northern Japan. For 'Tochihitomi', a strong EB cultivar, inflorescences emerged in all control plants grown under the natural photoperiod (≤ 14.5 h), and the number of inflorescences was not affected by any photoperiod treatment. In cultivars of intermediate EB strength (i.e., 'Summer-drop', 'Summer-tiara', 'Miyazaki-natsuharuka', and 'Summer-fairy'), flowering was < 100% under a 12-h photoperiod. The number of inflorescences was higher under the 24-h photoperiod than in control plants, with the effect of the duration of the photoperiod dependent on cultivar. For 'Natsuakari', a weak EB, 0 - 20% of plants flowered under the 12-h photoperiod, and 0% under the natural photoperiod. However, flower buds were induced in all plants treated with the 16-h or 20-h photoperiods for 2 weeks, or with the 24-h photoperiod for 1 week. Furthermore, the 16-h (2 weeks) and 20-h and 24-h (1 week) photoperiod treatments induced significantly more inflorescences than in control plants. Although the characteristics of flowering of EB strawberry plants differed between cultivars, we suggest that flowering can be promoted by a 24-h photoperiod applied for 1 - 4 weeks in cultivars of weak or intermediate EB strength. [ABSTRACT FROM AUTHOR]