Showing papers by "Xiamen University published in 1985"

Population identification of red-fin pargo, Parargyrops edita Tanaka, in Taiwan strait and Beibu Gulf

Abstract: This paper deals with population identification ofParargyrops edita Tanaka. Samples of spawning stocks were collected from Niushan-Penghu, Minnan-Taiwan shoal (Southern Fujian-Taiwan shoal) and Beibu Gulf during the spawning period 1981–1982. Morphological characters, both meristic and morphometric, are counted and measured respectively. The stock concept and intraspecific categories have been discussed. Some meristic characters as the number of left or right ventral fin spine, right ventral fin rays and abdominal vertebrae of this fish may be constant, others as the numbers of left or right pectoral fin rays and gill-rakers may have obvious geographical variation. Morphological characters have not attained the level of subspecific distinctness, no sub-species could be found among these stocks by means of coefficient of difference (C.D.). Basing upon the comparative analysis ofMdiff, the authors consider that stocks of Minnan-Taiwan shoal and Niushan-Penghu belong to the same local population, Taiwan Strait local population. By means of the discriminant function analysis and linear relationship analysis, statistical differences will be found to exist in meristic characters between the stock of Minnan-Taiwan shoal and that of Niushan-Penghu, so that the two are virtually different stocks or subpopulations. The stock of Beibu Gulf belongs to another called the Beibu Gulf local population. These two local populations are of allopatric distribution and show statistically significant difference between themselves. Among these stocks, the Minnan-Taiwan shoal stock is strongly influenced by the much more complicated environmental conditions of the mixed boundary region of the subtropical Sino-Japanese Subregion in the north and the tropical Indo-Malayan Subregion in the south. Thus its coefficient of variability (C.V.) is greater than those of the other two in the mean values of various meristic characters.

EHMO study of the modes of coordination activation and hydrogenation of dinitrogen on α-Fe(111) surface for ammonia synthesis

Abstract: The μ7(η2, ω2, ω′2) symmetrical flat-lying mode with double-end-on plus multiple-side-on coordination activation of N2 (mode-A) was compared with other modes, namely, μ7(η2, ω) single-end-on plus multiple-side-on inclined-mounting mode (mode-B), or μ7(η2, ω, ω′) unsymmetrical double-end-on plus multiple-side-on mode (mode-B′), and μ7(η2, ω) single-end-on plus multiple-side-on perpendicular-insertion mode (mode-C), based upon extended Huckel molecular orbital approach together with experimental results of laser Raman and IR spectroscopy of chemisorbed species on ammonia synthesis iron catalysts previously reported. As far as the chemisorption energy is concerned, mode-A appears to be the most favorable to the coordination activation of N2. Preliminary results of EHMO calculations also indicated N2 sufficiently activated with mode-A might react with slightly activated chemisorbed H2 with flat-lying coordination, or with 2H with bridging coordination, to form chemisorbed N2H2, or 2NH.