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A new compound (1) was found to accumulate when oat leaves were treated with elicitors. A reaction with peroxidase and avenanthramide B, an oat phytoalexin, in the presence of hydrogen peroxide resulted in the formation of 1. The chemical structure of 1 was determined to be a cyclic dehydrodimer of avenanthramide B based on spectroscopic analyses and chemical derivatization, and 1 was named bisavenanthramide B. 相似文献
895.
Ammonia synthesis by means of plasma over MgO catalyst 总被引:1,自引:0,他引:1
Kazuo Sugiyama Kiyoshi Akazawa Masaaki Oshima Hiroshi Miura Tsuneo Matsuda Okio Nomura 《Plasma Chemistry and Plasma Processing》1986,6(2):179-193
Ammonia synthesis from H2-N2 mixed gas was studied at room temperature in a glow-discharge plasma in the presence of metals or metal oxides. Magnesia (MgO) and calcia (CaO), which are oxides with solid basicity, revealed catalytic activity in the plasma synthesis of ammonia, although they are catalytically inactive in industrial ammonia synthesis. The acidic oxides (Al2O3, WO3, and SiO2-Al2O3) lead to the consumption of the reactant, i.e., the H2-N2 mixed gas. No ammonia was isolated. Metal catalysts showed higher activity than the above basic oxides. They have, however, different activities. The reaction was faster over the active materials than over sodium chloride (NaCl) or glass wool or in a blank reactor without any catalyst. 相似文献
896.
Wakita K Tokitoh N Okazaki R Nagase S 《Angewandte Chemie (International ed. in English)》2000,39(3):634-636
Solid-state, room-temperature stability for silabenzene 1 is granted by the bulky silane rendering kinetic inertness. Silabenzene 1 is synthesized in good yield from the crowded chlorosilane 2 with tert-butyllithium. The delocalized, aromatic nature of 1 was confirmed by NMR spectroscopy and the (1)J(Si-C) value, as well as calculations on an analogous silabenzene. 相似文献
897.
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Let d and n be positive integers with n ≥ d + 1 and 𝒫 ? ? d an integral cyclic polytope of dimension d with n vertices, and let K[𝒫] = K[?≥0𝒜𝒫] denote its associated semigroup K-algebra, where 𝒜𝒫 = {(1, α) ∈ ? d+1: α ∈ 𝒫} ∩ ? d+1 and K is a field. In the present paper, we consider the problem when K[𝒫] is Cohen–Macaulay by discussing Serre's condition (R 1), and we give a complete characterization when K[𝒫] is Gorenstein. Moreover, we study the normality of the other semigroup K-algebra K[Q] arising from an integral cyclic polytope, where Q is a semigroup generated by its vertices only. 相似文献