Spectrally Selective Emitters with Deep Rectangular Cavities Fabricated with Fast Atom Beam Etching

科研費報告書収録論文(課題番号:11555057・基盤研究(B)(2)・H11～H13/研究代表者:湯上, 浩雄/太陽熱光起電力による高温輻射-電力直接変換システムの開発

Modal mineral abundances and the differentiation trends in primitive achondrites

The mineral distribution maps of polished thin sections (PTSs) of acapulcoites (Acapulco, Allan Hills (ALH) 77081,ALH78230,Elephant Moraine (EET) 84302 and Yamato (Y)-8307) and lodranites (Gibson, MacAlpine Hills (MAC) 88177,Y-74357,Y-75274,Y-791491 and Y-8002), winonaites (Tierra Blanca, Y-74025,Y-75305 and Y-8005), silicate inclusions in IAB iron meteorites (Y-791058 and Caddo County), and an H7 chondrite (Y-75008) were made from elemental distribution maps of the electron probe microanalyzer to obtain quantitative modal abundances of minerals, and to study variations in the distributions of minerals. The trends of variations of chemical compositions of minerals were also studied. Other related meteorites, ALH81187 and ALH81261 (acapulcoites) were also studied for comparison. Textures of these meteorites are various from fine-grained recrystallized chondrite-like materials including minerals known in chondrites, to coarse-grained materials with opaque mineral grains which have complex shapes, often with large aggregates of Fe-Ni metal. The variety of modal abundances and textures of primitive achondrites suggests that heterogeneity produced by local segregation of partially melted materials on their parent bodies can explain the origin of variation of primitive achondrites. Systematic variations in the relative abundances of olivine, augite+plagioclase, and orthopyroxene shows that the plagioclase-augite-rich region of Caddo County B3A (augite+plagioclase=96.8%) can be taken as an endmember of the variations observed in other primitive achondrites. The orthopyroxene-chromite-rich region of EET84302,19 (orthopyroxene=95.1%) and Y-74357 (olivine=83.2%) are other types of segregated materials. The mechanism proposed in this paper reveals the early differentiation processes of planetesimals from primitive source materials

Comparisons of textural and chemical variations of minerals in some primitive achondrites and an H7 chondrite, with reference to their formation and cooling histories

The textures and trends of chemical variations of minerals in five acapulcoites (Acapulco, Allan Hills (ALH)-77081,ALH-78230,ALH-81187 and ALH-81261), two winonaites (Tierra Blanca and Yamato (Y)-74025) and an H7 chondrite (Y-75008) were studied for comparison to deduce their formation conditions and subsolidus cooling histories. The mineral distribution maps of polished thin sections (PTSs) of ALH-78230,Tierra Blanca, Y-74025,Y-75008,were made from elemental distribution maps of the electron probe microanalyzer to study variations in the distributions of minerals. Textures of these meteorites are fine-grained recrystallized chondrite-like materials including minerals known in chondrites. Opaque mineral grains have complex shapes, often with large aggregates of Fe-Ni metals, as was observed in Y-74025. Elongation parameters defined as L/(4πS)^ (=A), range from 1.4 to 1.6 for acapulcoites, where L is length and S is area of a grain. Despite their formation in different parent bodies, the variety of textures of primitive achondrites suggests that heterogeneity produced by local segregation of partially melted materials on their parent bodies can explain the origin of variation of primitive achondrites. CaO zoning of orthopyroxene can be attributed to the segregation and migration of Ca-rich partial melts. Mg/Fe variations of olivine can be explained by subsolidus reduction, when their parent body was disrupted or fractured by an impact while its interior was still hot

On the experiments of Surfatron concept with use of capillary plasma.

In the middle of 1980th, the VpxB concept for accelerating electrons are found by Nishida et al, with the use of plasma wave excited by high power microwave in the interaction with weakly magnetized plasma. This acceleration concept was called “Surfatron effect” in the relativistic regime. However, there is no experimental evidence so far in the relativistic regime, although the acceleration efficiency is highest in all of the concepts based on the plasma wave acceleration scheme, and we are now under experiments. In order to make longer the acceleration distances, there are several ideas including 1)ducting of the electromagnetic waves (EM wave) in the preformed plasma, 2)selfchanneling of the EM waves, and others. In this paper, the experimental results are shown on the ducting phenomena by using strong microwave for simulating the laser ducting, and on the capillary plasma scheme