一种液晶环氧树脂固化中扩散控制动力学研究

根据扩散控制反应的基本原理 ,建立了合适的反应模型 ,描述了 4 ,4′ 二 ( 2 ,3 环氧丙氧基 )偶氮苯(DGEAP) / 4,4′ 二氨基二苯甲烷 (DDM)环氧树脂的固化行为 .该模型认为 ,随着环氧基团反应程度的提高 ,基团的反应半径将受到影响 .当体系中出现了介晶基元的有序排列时 ,与之相连的反应基团的分布也受到影响 ,有序区内的局部浓度将变大 ,产生假浓度效应 ,并最终影响扩散控制反应动力学 .通过与普通环氧树脂固化动力学的比较 ,证实了这一效应 .     

Synthetic enantiopure aziridinomitosenes: preparation, reactivity, and DNA alkylation studies

An enantiocontrolled route to aziridinomitosenes had been developed from l-serine methyl ester hydrochloride. The tetracyclic target ring system was assembled by an internal azomethine ylide cycloaddition reaction based on silver ion-assisted intramolecular oxazole alkylation and cyanide-induced ylide generation via a labile oxazoline intermediate (62 to 66). Other key steps include reductive detritylation of 26, methylation of the N-H aziridine 56, oxidation of the sensitive cyclohexenedione 68 to quinone 70, and carbamoylation using Fmoc-NCO. Although the aziridinomitosene tetracycle is sensitive, a range of protecting group manipulations and redox chemistry can be performed if suitable precautions are taken. A study of DNA alkylation by the first C-6,C-7-unsubstituted aziridinomitosene 11a has been carried out, and evidence for DNA cross-link formation involving nucleophilic addition to the quinone subunit is described.     

STUDIES ON cis-trans-ISOMERIZATION AND REACTION KINETICS OF A μ, η~2-VINYL LIGAND IN A TRIOSMIUM CLUSTER

The dihydride cluster H_2O_(s_3)(CO)_(10) reacts with ethyne to give a cis-adduct [O_(s_3)H(μ,η~2-CH=CH_2)(CO)_(10)]. The high deuterated cluster D_2O_(s_3)(CO)_(10), the reaction of D_2O_(s_3)(CO)_(10)with ethyne C_2H_2 to form the vinyl product cluster [O_(s_3)D(μ, η~2-CH=CHD)(CO)_(10)], and thereaction of H_2O_(s_3)(CO)_(10) with the deuterated ethyne C_2D_2 to form [O_(s_3)H(μ,η~2-CD=CDH)(CO)_(10)] have been reported primarily in this paper. The two cis-adducts undergo cis-trans-isomerization of μ,η~2-vinyl ligands under a small amount of the nucleophile pyridine. Usingthe combination of deuteration and dynamic ~1H,~2H NMR spectra, we report the experimen-tal evidence determined by the dynamic ~1H, ~2H NMR spectra, mechanism, and kinetic dataof the isomerization.     

Synthesis and X-ray crystal structure of oxamido-bridged heterobinuclear Ni(Ⅱ)-Cu(Ⅱ) complexes

The two complexes [Ni(oxen)Cu(L)2](ClO4)2.xH2O (L=2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen)) have been synthesized, where oxen is N,N'-bis(2-aminoethyl)oxamido di-anion. The crystal structure of [Ni(oxen)Cu(bpy)2](ClO4)2.CH3OH has been determined by X-ray diffraction method. The crystal is triclinic system, space group P1 with a=12.179(1),b=12.298(2), c=11.476(2) A, a=97.57(1), B=97.52(1), 7=80.29(2), V=1669.04(67) A3, Z=2, Dcalcd=1.667 g/cm3. The structure has been refined to final R of 0.076 and Rw of 0.080, respectively. The complexes have an extended oxamido-bridged structure and consist of Ni(Ⅱ) ion in a square planar environment and Cu(Ⅱ) ion in a distorted octahedral environment.     

热处理过程中聚酯长丝的形态变化

在自制的红外三因素处理机上~[1],用红外加热在定张力下对聚对苯二甲酸乙二酯(PET)成品长丝进行热处理(二次定型)。用X-光衍射(WAXS)、X-光小角散射(DAXS)、红外光谱(IR)和双折射方法,测定样品的热收缩、结晶度、晶粒尺寸和取向、非晶取向、长周期和链折叠带强度。所得形态参数的变化表明,处理温度在200℃以上时,张力不再阻碍链折叠。不同定张力样品的形态研究表明,存在阻碍链折叠的某个张力转折值。本文条件下,这个张力值为f_(critical)=0.066g/dtex 。张力大于此值,链折叠过程受阻。     

An Efficient Method for the Synthesis of Acyl-diazenes Using NaNO_2/NaHSO_4·H_2O

Azo compounds are widely utilized as analytic reagents and dyes1, they can also be used in material of non-linear optics, material of optics information storing in laser disks, and dyes with oil solubility in photochromy in modern technology2. Recently, many noteworthy studies have shown that some azo compounds possess excellent optical memory and photoelectric properties3,4. For example, polymer scaffolds bearing azobenzene-potential are useful for optical information storage, azo-dye doped…     

Molecular Recognition of Bridged Bis(β-cyclodextrin)s Linked by Phenylenediseleno Tether on the Primary or Secondary Side with Fluorescent Dyes

A Novel β-cyclodextrin dimer,2,2′-o-phenylenediseleno-bridgedbis(β-cyclodextrin)(2),has been synthesized by reaction ofmono-[2-O-(p-tolylsulfonyl)]-β-cyclodextrin and poly(o-phenylenediselenide).The complexation stability constants(K_s)and Gibbs free energy changes(-ΔG°)of dimer 2 with fourfluorescence dyes,that is,ammonium 8-anilino-1-naphthalene-sulfonate(ANS),sodium 6-(p-toluidino)-2-naphthalenesul-fonate(TNS),Acridine Red(AR)and Rhodamine B(RhB)have been determined in aqueous phosphate buffer solution(pH=7.2,0.1 mol·L~(-1)at 25℃ by means of fluorescence spec-     

Synthesis, Structure and Conductivity of the New Charge-transfer Salt (ET)_2(CH_2=CH-CH_2-SO_3)·H_2O

ET is one of the most famous electron-donor molecules, which forms charge-transfer complexes (abbr. CT-complexes) with various types of counterions. These complexes have received intense attention because a wide range of physical properties such as conductivity and superconductivity1, ferromagnetism2-4 and nonlinear optical properties5 was found in these materials. Although the majority of the ET-based CT-complexes were prepared by combining with inorganic counterions, CT-complexes with o…     

Synthesis, Structure and Characterization of [Cu(2,2'-bpy)2][{Cu(2,2'-bpy)2}2W12O40(H2)]·4H2O

An organic-inorganic compound [Cu(2,2'-bpy)2][{Cu(2,2'-bpy)2}2W12O4o(H2)]·4H2O (Mr = 4048.00) was prepared from the hydrothermal reaction of Na2WO4·2H2O, CuCl2·2H2O,2,2'-bipyridine (2,2'-bpy) and H2O at 160 ℃ for 4 days. The compound crystallizes in the monoclinic system, space group P21/n with a = 18.9196(8), b = 20.4212(8), c = 21.8129(9)(A), β=96.992(3)°, V= 8365.0(6) (A)3, Dc= 3.214 g/cm3, Z = 4,μ(MoKα) = 17.269 mm-1 and F(000) = 7324.Of the 119837 total reflections, 17315 were unique (Rint = 0.0489). The final R = 0.0385 and wR =0.0770 for 11142 observed reflections with I ＞ 2σ(I). Single-crystal X-ray diffraction reveals that the structure is composed of [{Cu(2,2'-bpy)2}2W12O40(H2)]2- anions, discrete [Cu(2,2'-bpy)2]2 cations and lattice water molecules, and the anion is made up of a {W12O40(H2)}6- α-Keggin core decorated with two {Cu(2,2'-bpy)2}2 groups through bridging oxygen atoms.     

激光通道传输热特性对远场光束质量的影响

 通过仿真计算分析了激光在光束控制系统通道内传输所产生的热效应及其对远场光束质量的影响。激光传播由近轴波方程描述，用快速傅里叶变换技术求解；激光热效应引起的流场密度变化采用完全Navier-Stokes方程计算。计算给出了不同波长、不同吸收系数条件下的远场光斑情况。计算结果表明，在典型的工作条件和状态下，较高能量激光在光束控制系统通道内产生的热效应影响不容忽视，它会明显降低远场目标处的能量集中度，增大光斑的发散。