大气污染下具HollingⅡ功能性反应的种群生存条件

从生态毒理学的角度,建立了具HollingⅡ功能性反应的大气污染模型,研究了污染系统中种群的弱持续生存等条件,得到了常数输入下系统奇点的全局渐近稳定性.     

One-dimensional Zigzag Chain Coordination Polymer [Zn(μ-phth)(imi)_2]_∞ Bridged by ο-Phthalato

1 INTRODUCTION The research on coordination polymers is currently of great interest because of their fascinating structure diversity and potential applications as functional materials, which possess potential functions such as molecular recognition, enantiomer separation, chiral synthesis, photoluminescent and selective catalysis[1]. Recently many coordination polymers with special physical and chemical properties have been synthesized and reported[2]. The structures and functions of th…     

从捕光天线到反应中心分子能量传递研究

利用飞秒时间分辨光谱技术研究了PSⅡ中捕光天线LHCⅡ内Chla分子和β-Car分子传递光能到反应中心的时间特性,实验测得Chla分子用了25 ps,β-Car分子用了250 ps.理论研究得出:25 ps是相邻Chl分子之间随机转移传能的时间常数,250 ps是LHCⅡ内相邻β-Car分子,通过Chla分子单步FÖrster共振传递、Dexter电子交换机制、激子转移把能量转移到反应中心的总时间.理论计算与实验结果基本符合,激子随机转移传递激发能快而有效.     

BEPC II氦低温系统的初步设计

低温超导技术将应用于第二代北京正负电子对撞机 (BEPC II)。文中所设计的大型氦低温系统将为第二代北京正负电子对撞机的三个磁体 :超导螺线管磁体、插入四极铁磁体和高频超导腔磁体提供 4 .5 K下 80 0 W的冷量和 6 0 .0 L/ h的液氦产量。由于每个用户都有其特定的工作要求 ,该系统为每个用户配置一个控制杜瓦 ,以满足磁体的工作要求。     

Synthesis, Crystal Structure and Magnetic Properties of a Novel Azide-bridged Copper（Ⅱ） Coordination Polymers Containing Nitroxy Nitroxide

A novel azide-bridged copper(Ⅱ) coordination polymer, [Cu3(NITpPy)4(N3)6]n (NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidazline-3-oxide-1-oxyl), was structurally and magnetically characterized. It crystallizes in the triclinic space group P with a = 7.6932(10), b = 14.5556(19), c = 16.122(2) , α = 108.443(2), β = 95.251(2), γ = 104.236(2)°, V = 1631.7(4) 3, C48H64Cu3N30O8, Mr = 1379.87, Z = 1, Dc = 1.404 g/cm3, μ(MoKα) = 1.041 mm-1, F(000) = 713, the R = 0.0510 and wR = 0.1185 for 4285 observed reflections with I > 2σ(I). X-ray analysis reveals that the Cu(Ⅱ) ions are linked by nitrogen atom of μ1,1 azido ligands to form a Cu-Cu-Cu unit. The units are linked by μ1,3 azido ligands through a bridging style to form a one-dimensional coordination polymer. The variable-temperature magnetic susceptibility data of the complex show ferromagnetic interactions in the complex.     

Ionothermal Syntheses and Crystal Structures of Two Cobalt（Ⅱ） Compounds：Co（2,2＇-bpy）_2Br_2 and Co（1,10-phen）_2Br_2

Two cobalt(Ⅱ) compounds,Co(2,2-bpy) 2 Br 2 (1,2,2-bpy=2,2-bipyridyl) and Co(1,10-phen) 2 Br 2 (2,1,10-phen=1,10-phenanthroline),have been prepared under ionothermal reactions using the 1-propyl-3-methylimidazolium bromide ionic liquid solvent.Single-crystal X-ray analyses reveal that 1 crystallizes in a monoclinic space group P2 1 /c,with a=8.5509(13),b=14.804(2),c=15.650(2),β=97.119(2) o,V=1965.8(5) 3,Z=4,C 20 H 16 Br 2 N 4 Co,M r=531.12,D c=1.795 g/cm 3,μ=4.950 mm-1,F(000)=1044,the final R=0.0467 and wR=0.0736 for 2291 observed reflections with I > 2σ(Ⅰ).Complex 2 crystallizes in a monoclinic space group P2 1 /n,with a=10.4237(8),b=16.8657(12),c=12.4945(9)b,β=102.110(1) o,V=2147.7(3) 3,Z=4,C 24 H 16 Br 2 N 4 Co,M r=579.16,D c=1.791 g/cm 3,μ=4.540 mm-1,F(000)=1140,the final R=0.0431 and wR=0.1042 for 3470 observed reflections with I > 2σ(Ⅰ).The mononuclear molecules of 1 are linked by the C-H···Br hydrogen bonds and π-π interactions to form a three-dimensional supramolecular framework structure.The C-H···Br hydrogen bonds and π-π interactions link the mononuclear molecules of 2 to give a two-dimensional layer structure.     

Hydrothermal Synthesis and Crystal Structure of An Iron（Ⅱ） Formate [H3CO3] [Fe（HCO2）3]

An iron(Ⅱ) formate [H 3 CO 3 ][Fe(HCO 2) 3 ] (1) has been synthesized under hydro-thermal conditions and characterized by single-crystal X-ray diffraction analysis.Complex 1 crystallizes in the orthorhombic system,space group Pnna with a=8.4130(4),b=11.8306(6),c=8.9468(4),α=106.527(4),β=105.876(4),γ=103.173(4) o,M r=253.94,V=890.48(7)3,Z=4,D c=1.894 g/cm 3,μ=1.721 mm-1,F(000)=512,R int=0.0164,the final R=0.0323 and wR=0.0998 for 979 observed reflections (I > 2σ(I)).1 exhibits a 3D open microporous framework formed by formate anions bridging Fe(Ⅱ) ions.