Self-regulation in infinite populations with fission-death dynamics

The evolution of an infinite population of interacting point entities placed in ${\mathbb{R}}^d$ is studied. The elementary evolutionary acts are death of an entity with rate that includes a competition term and independent fission into two entities. The population states are probability measures on the corresponding configuration space and the result is the construction of the evolution of states in the class of sub-Poissonian measures, that corresponds to the lack of clusters in such states. This is considered as a self-regulation in the population due to competition.     

The Crystal Structures of Some 1-Aryl-5-methyl-1,2,3-triazole Derivatives

Abstract  The two 1-aryl-5-methyl-1,2,3-triazole derivatives were prepared by the 1-aryl-5-methyl-1,2,3-triazol-4-carboxylic acids 3. The yielded products 4a–b were confirmed by NMR, MS, IR spectra. We investigated the crystalline structure of compounds 4a and 4b. Compound 4a, C₉H₈BrN₃, Mr = 238.09, crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 11.660(2), b = 7.668(2), c = 11.818(2) ?, α = 90.00, β = 116.01(3), γ = 90.00o. V = 949.6(3) ?³, Z = 4, Dx = 1.665 Mg m⁻³. The final R was 0.0477. Compound 4b, C₁₃H₁₁N₃, Mr = 209.25, crystallized in the orthorhombic space group Pbca with unit cell parameters a = 10.373(2) ?, b = 11.691(2) ?, c = 17.579(4) ?, α = 90.00o, β = 90.00o, γ = 90.00o, V = 2131.8(7) ?³, Z = 8, D _m = 1.304 Mg m⁻³. The final R was 0.0565. Index Abstract  The two 1-aryl-5-methyl-1,2,3-triazole derivatives were prepared by the 1-aryl-5-methyl-1,2,3-triazol-4-carboxylic acids 3. The yielded products 4a–b were confirmed by NMR, MS, IR spectra. We investigated the crystalline structure of compounds 4a and 4b. Compound 4a, C9H8BrN3, Mr = 238.09, crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 11.660(2), b = 7.668(2), c = 11.818(2)  ?, α = 90.00, β = 116.01(3), γ =90.00o. V = 949.6(3) ?³, Z = 4, Dx = 1.665 Mg m⁻³. The final R was 0.0477. Compound 4b, C13H11N3, Mr = 209.25, crystallized in the orthorhombic space group Pbca with unit cell parameters a = 10.373(2) ?, b = 11.691(2) ?, c = 17.579(4) ?, α = 90.00o, β = 90.00o, γ = 90.00o, V = 2131.8(7) ?³, Z = 8, D _m = 1.304 Mg m⁻³. The final R was 0.0565.      

联二萘酚类磷酸吡哆醛模拟酶的合成与应用研究进展

模拟酶化合物的合成与应用研究具有重要的理论和实际意义。近年来研究的一些联二萘酚类磷酸吡哆醛模拟酶具有氨基酸构型转换的功能,并可用于手性氨基醇的对映选择性识别。本文简要介绍了该类化合物的合成方法,综述了近年来联二萘酚类磷酸吡哆醛模拟酶在手性氨基酸构型转换、手性氨基醇对映选择性识别以及萃取拆分等方面的应用。     

The Full Study of Planar Quadratic Differential Systems Possessing a Line of Singularities at Infinity

In this article we make a full study of the class of non-degenerate real planar quadratic differential systems having all points at infinity (in the Poincaré compactification) as singularities. We prove that all such systems have invariant affine lines of total multiplicity 3, give all their configurations of invariant lines and show that all these systems are integrable via the method of Darboux having cubic polynomials as inverse integrating factors. After constructing the topologically distinct phase portraits in this class we give invariant necessary and sufficient conditions in terms of the 12 coefficients of the systems for the realization of each one of them and give representatives of the orbits under the action of the affine group and time rescaling. We construct the moduli space of this class for this action and give the corresponding bifurcation diagram. Dedicated to Professor Zhifen Zhang on the occasion of her 80th birthday     

A Stereostructural Study of 17-Hydroxylupanine and its Perchlorate

Summary.  The bisquinolizidine carbinolamine 17-hydroxylupanine was synthesized de novo from lupanine using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; its structure was established by NMR techniques. The equatorial position of the hydroxy group as well as the prevailing boat form of ring C were determined. As expected, the carbinolamine converted into the C17=N16 anhydronium perchlorate upon treatment with HClO₄. NMR analysis of the salt revealed a conformational equilibrium within rings A and D, whereas rings B and C remain rigid. Received March 13, 2000. Accepted March 21, 2000     

多组态Dirac-Fock方法与准相对论组态相互作用方法的比较研究

利用多组态Dirac-Fock(MCDF)方法与准相对论组态相互作用方法,分别详细计算了低Z、中Z和高Z原子(离子)各个壳层上电子的束缚能、平均轨道半径、总束缚能、激发能、精细结构能级以及类Ne等电子系列离子的2p53s 1,3P1-2p6 1S0跃迁能,并且对这两种方法的结果进行了数值比较.     

氨基酸合成方法研究—(XI)N-取代亚氨酸酯与芳醛缩合产物—去氢氨基酸衍生物的构型及其NMR研究

通过~1H NMR、NOE差谱和门控去偶~(13)C NMR等的研究确定了新合成的五对α-去氢氨基酸衍生物的构型,并利用部分弛豫、APT~(13)C NMR二维碳氢相关谱及~(13)C-~(19)F偶合常数等对NMR谱线进行了归属.     

金属卟啉催化烷烃选择性氧化反应的研究进展

金属卟啉作为一种仿生催化剂,能够实现在温和条件下对分子氧的催化活化,在催化烷烃氧化反应中显现出巨大的潜力.本文总结了金属卟啉结构对烷烃选择性氧化结果的影响,并介绍了近期金属卟啉催化剂应用于烷烃氧化反应的研究进展,最后探讨了金属卟啉催化剂在催化烷烃选择性氧化反应中存在的问题及发展前景.     

Nb^30＋,Na—like离子自电离速率和自电离分支比

用组态相互作用方法，研究了Ｎｂ３０＋，Ｎａ－ｌｉｋｅ２ｐ５３ｌ３ｌ′（ｌ，ｌ′＝０，１，２）内壳层电子激发跃迁的自电离速率和自电离分支比，结果表明自电离速率对自电离分支比的贡献最大。     

铅原子J=2偶宇称Rydberg系列组态相互作用对光谱强度的影响

实验获得了碳族原子铅的偶宇称J=0和2的束缚Rydberg态能级,利用六通道模型分析了铅原子J=2的束缚Rydberg系列之间强烈的组态相互作用对电离光谱的影响.