Light-Figure Phenomena Revealed and Crystal Faces Developed by Chemically Etched Nickel-Copper Alloy Crystals

The light-figure phenomena have been observed with single crystals of nickel-copper alloys containing 5～95 percent copper, etched with various chemical reagents, in order to obtain information regarding crystal faces developed by etching and to examine the suitability of the observed light figures to the orientation determination. The etching with boiling saturated aqueous solution of ferric chloride produces distinct light figures, suitable for the orientation determination, for all of alloy crystals, while any other reagent reveals only indistinct or no light figure. The main crystal faces developed by etching with ferric chloride solution are the {hk0}. {110} and {111}-vicinal faces, hk0 varying from 910 for nickel crystals over 610 for 20%Cu alloy crystals to 210 for 95%Cu alloy crystals

The Light-Figure Phenomenon Revealed and Crystal Planes Developed by Etching in Tetragonal Tin Crystals and the Determination of Their Crystal Orientations by the Light-Figure Method. II : Orientation Determination by Light Figures

The application of light figures to the orientation determination of single crystal rods of tetragonal tin has been studied and the procedure for the perfect, accurate, and rapid determination has been worked out. Full accounts are given of the geometrical relationships and etching technique required for the orientation determination, of the directly and accurately measurable ranges and kinds of orientation angles, of the stereographic representation of crystal orientations, and of the accuracy and actual examples of the determination. The perfect determination of crystal orientations can be made with an accuracy within 0.1°by the use of {001}, {100} and {101} light figures revealed by etching with concentrated aqua regia. It is shown that the orientation determination by this method agrees well with that by the X-ray diffraction method

On the Production of Single Crystals of Zinc, Bismuth and Tin by Sucking Up from Their Melts

The preparation of single crystals of zinc, bismuth and tin by sucking up from their melts was tried by the use of simple equipment and procedure and the effect of growing conditions upon the percentage of success and orientations of single crystals produced was studied. Single crystals, 5 mm in diameter and 5～7 cm in length, could be made with 20, 50 and 50 percent success for zinc, bismuth and tin, respectively, and they show a dominant preference of crystal orientations nearly perpendicular to the principal crystallographic axis, namely the hexagonal axis [0001] for zinc, trigonal axis [111] for bismuth, or tetragonal axis [001] for tin

Light Figures and Surface Structures Revealed by Chemically Etched Germanium Single Crystals

Light figures projected on a plate screen from germanium single crystals, polished mechanically and etched with various chemical reagents, are examined in order to find out light figures or etching directions suitable for the orientation determination. In. formation regarding surface structures of germanium single crystals developed by mechanical polishing and by chemical etching has been obtained from the analysis of the observed light figures and from microscopic observations of crystal surfaces. It has been found that distinct light figures suitable for the orientation work are obtained by a short time etching with concentrated nitric acid plus water (1 : 1 and 3 : 7 ; 70℃), with concentrated nitric acid plus water plus hydrofluoric acid plus silver nitrate (45 cc+45 cc+10 cc+50 or 20 mg, and 20 cc+40 cc+40 cc+2 g), with hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4), and with 30 percent hydroperoxide (100℃). Among these etchants, hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4) is most suited for accurate orientation determination. Generally, crystal faces developed by etching have been found to be those belonging to the principal crystal zones, but dilute nitric acid heated at 70℃ develops some additional high-index crystal faces belonging to a high-index crystal zone. There is a tendency that low-index crystal faces appear by a short time etching and high-index ones by a prolonged etching. It is to be added that relatively clear light figures are obtained on germanium crystals as polished with silicon carbide powder

Effects of Growth Rates and Cooling Rates on Defect Generation in Melt-Grown Copper Crystals(Physics)

Single crystals of zone-refined Cu were grown from the melt at growth rates ranging from 0.1 to 29.0 mm/min and with cooling rates of the crystal after growth varying from 0.24 to 45℃/min. It was found that the growth rate had a very important effect on the generation of dislocations and their arrays, but the cooling rate of the crystal after growth had an important effect only when the crystal had been solidified at a rate of 0.1 mm/min

AtUBL5 regulates growth and development through pre-mRNA splicing in Arabidopsis thaliana

Ubiquitin-like proteins play important roles in the regulation of many biological processes. UBL5 (Ubiquitin-like protein 5)/Hub1 (Homologous to ubiquitin 1), a member of the ubiquitin family, acts as a ubiquitin-like modifier on a specific target, the spliceosomal protein Snu66, in yeast and human cells. The 22nd aspartic acid (Asp22) is involved in the attachment of Hub1 to the Hub1 interaction domain (HIND) of Snu66 in yeast to modulate spliceosomal activity. Hub1 differs from other modifiers which interact covalently with their targets. It modulates pre-mRNA splicing by binding to Snu66 non-covalently in both yeast and human cells. However, the molecular mechanisms of Hub1-mediated pre-mRNA splicing in plant systems remains unclear. To better understand the function of Hub1 in plants, we examined the role of this ubiquitin-like modifier in Arabidopsis thaliana, which has two Hub1 homologues. Arabidopsis UBL5/Hub1(UBL5) is highly conserved at the amino acid level, compared to eukaryotic homologues in both plants and animals. In this study, phenotypic analysis of A. thaliana with reduced UBL5 gene expression, generated by RNA interference of AtUBL5a and AtUBL5b were performed. Interestingly, knock down plants of AtUBL5 showed abnormalities in root elongation, plant development, and auxin response. AtUBL5b is highly expressed in the vascular tissue of the leaf, stem, and root tissue. Yeast two-hybrid analysis revealed that AtUBL5a and AtUBL5b interact with the putative splicing factor AtPRP38 through its C-terminal domain (AtPRP38C). Knock down of AtUBL5b resulted in a pattern of insufficient pre-mRNA splicing in several introns of AtCDC2, and in introns of IAA1, IAA4, and IAA5. Defects of pre-mRNA splicing in an AtPRP38 mutant resulted in an insufficient pre-mRNA splicing pattern in the intron of IAA1. Based on these results, we showed that AtUBL5b positively regulates plant root elongation and development through pre-mRNA splicing with AtPRP38C in A. thaliana