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971.
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The initial stages of interface formation for Ag deposited onto Ge(100)-(2 × 1) were studied with high-energy electron diffraction and high- resolution photoemission. The surface core-level energies for clean Ge(100)-(2 × 1) were not changed with the deposition of about one monolayer of Ag, indicating that there was no chemical reaction or atomic intermixing. The Ag nucleated at a coverage of about monolayer and showed three-dimensional growth for higher coverages. 相似文献
973.
We calculate energy spectra and angular distributions of single and correlated spectra after the absorption of stopped pions in nuclei. We assume: The pion is abosrbed by a pair of nucleons; these primary nucleons may leave the nucleus directly or only after one or more collisions with other nucleons. We propose a multiple scattering expansion for the intranuclear cascade after pion absorption. Various experimental data are successfully described in shape and absolute magnitude. The ratio Rnp = R(π?np → nn)/R (π? pp → np) is determined from the experimental proton spectra: Rnp = 13 ± 6. 相似文献
974.
Chiang C. Mei 《Wave Motion》1979,1(2):113-122
The diffraction of high-frequency P waves incident along the axis of a slender cavity of finite length is investigated. The diffracted field can be divided into several regions. Near the cavity SV waves are generated by mode conversion but they are confined to two slanted strips on the sides of the cavity. The boundary layers along the edges of these strips are also studied. Diffraction of incident SV waves is also considered but the P waves generated by mode conversion affect only the immediate neighborhood of the cavity. Similar problems with a rigid slender inclusion are briefly discussed. 相似文献
975.
F. P. Chiang 《Optics and Lasers in Engineering》1981,2(3):151-160
Strain concentration factors of circular cylinders with circular and square holes are analysed by a white light speckle method. We introduce a four-aperture arrangement for recording white light speckles and find that the resulting isothetics are better in quality. 相似文献
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Development of Genetic Dereplication Strains in Aspergillus nidulans Results in the Discovery of Aspercryptin
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Dr. Yi‐Ming Chiang Dr. Manmeet Ahuja C. Elizabeth Oakley Dr. Ruth Entwistle Dr. Anabanadam Asokan Dr. Christoph Zutz Dr. Clay C. C. Wang Dr. Berl R. Oakley 《Angewandte Chemie (International ed. in English)》2016,55(5):1662-1665
To reduce the secondary metabolite background in Aspergillus nidulans and minimize the rediscovery of compounds and pathway intermediates, we created a “genetic dereplication” strain in which we deleted eight of the most highly expressed secondary metabolite gene clusters (more than 244,000 base pairs deleted in total). This strain allowed us to discover a novel compound that we designate aspercryptin and to propose a biosynthetic pathway for the compound. Interestingly, aspercryptin is formed from compounds produced by two separate gene clusters, one of which makes the well‐known product cichorine. This raises the exciting possibility that fungi use differential regulation of expression of secondary metabolite gene clusters to increase the diversity of metabolites they produce. 相似文献