对甲苯磺酸掺杂聚吡咯的合成、表征及其对金属镁的防腐蚀性能研究

以对甲苯磺酸为掺杂剂, 三氯化铁为氧化剂, 化学氧化吡咯制备了对甲苯磺酸掺杂聚吡咯. 考察了掺杂剂与氧化剂的用量对掺杂聚吡咯电导率的影响, 得到了高电导率聚吡咯的优化条件, 用UV, IR和SEM对其结构和形貌进行了表征. 结果表明, n(对甲苯磺酸)∶n(吡咯)∶n(三氯化铁)＝0.75∶1∶0.5时, 合成的聚吡咯的形貌规则, 电导率达42.7 S•cm^－1. 以聚吡咯为功能成分, 环氧树脂为成膜物质, 得到一种功能膜, 旋涂于金属镁表面, 采用极化曲线和开路电位考察了含有聚吡咯的膜层对金属镁的防腐蚀性能. 结果表明, 含有聚吡咯的膜层对金属镁有很好的防腐蚀性能, 腐蚀电流为0.0981 A, 腐蚀电位为－0.88 V, 在膜层与金属镁之间形成了一层钝化膜.     

Ba3[Ge2B7O16(OH)2](OH)(H2O) and Ba3Ge2B6O16: novel alkaline-earth borogermanates based on two types of polymeric borate units and GeO4 tetrahedra

Two new barium borogermanates with two types of novel structures, namely, Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) and Ba(3)Ge(2)B(6)O(16), have been synthesized by hydrothermal or high-temperature solid-state reactions. They represent the first examples of alkaline-earth borogermanates. Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) crystallized in a polar space group Cc. Its structure features a novel three-dimensional anionic framework composed of [B(7)O(16)(OH)(2)](13-) polyanions that are bridged by Ge atoms with one-dimensional (1D) 10-membered-ring (MR) tunnels along the b axis. The Ba(II) cations, hydroxide ions, and water molecules are located at the above tunnels. Ba(3)Ge(2)B(6)O(16) crystallizes in centrosymmetric space group P1. Its structure exhibits a thick layer composed of circular B(6)O(16) units connected by GeO(4) tetrahedra via corner sharing, forming 1D 4- and 6-MR tunnels along the c axis. Ba1 ions reside in the tunnels of the 6-MRs, whereas Ba2 ions are located at the interlayer space. Both compounds feature new types of topological structures. Second-harmonic-generation (SHG) measurements indicate that Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) displays a weak SHG response of about 0.3 times that of KH(2)PO(4). Optical, thermal stability, and ferroelectric properties as well as theoretical calculations have also been performed.     

四个Cd(Ⅱ)配位聚合物:辅助配体对晶体结构以及荧光性能的影响

采用溶剂热的方法,将配位模式丰富的多羧酸有机配体5-(2-硝基-4-羧基苯氧基)-间苯二甲酸(H3ncpoi)与Cd~(2+)离子以及不同的辅助配体原位组装而成4个新的配位聚合物晶体:[Cd(Hncpoi)(2,2′-bpy)(H2O)]n(1),{[Cd2(Hncpoi)2(bpyp)(H2O)4]·3H2O}n(2),{[Cd2(Hncpoi)2(azpy)(H2O)2]·2H2O}n(3),{[Cd2(Hncpoi)2(dpe)(H2O)2]·2H2O}n(4),其中H3ncpoi为5-(2-硝基-4-羧基苯氧基)-间苯二甲酸,2,2′-bpy为2,2′-联吡啶,bpyp为1,4-二-吡啶基-4-亚甲基-哌嗪,azpy为4,4′-偶氮吡啶,dpe为1,2-二-(4-吡啶基)乙烯。对4个配合物进行了X射线单晶衍射、粉末衍射,元素分析、热重、荧光光谱等表征。X射线单晶结构分析表明,配合物1,2具有一维链状结构,而配合物3,4则具有二维(4,4)格子层状结构,一维链和二维层之间通过分子间作用力连接成三维超分子结构。进一步研究表明,辅助配体的构型、配位方式等对晶体结构具有决定性作用。与此同时,对几个配合物的荧光光谱进行分析,发现不同的辅助配体对配合物的荧光性能有着显著的影响。     

Syntheses, crystal structures and luminescent properties of new lanthanide(III) organoarsonates

The first examples of lanthanide(III) organoarsonates, Ln(L(1))(H(2)O)(3) (Ln = La (1), H(3)L(1) = 4-hydroxy-3-nitrophenylarsonic acid), Ln(L(1))(H(2)O)(2) (Ln = Nd (2), Gd (3)), and mixed-ligand lanthanide(III) organoarsonates, Ln(2)(HL(1))(2)(C(2)O(4))(H(2)O)(2) (Ln = Nd (4), Sm (5), Eu (6)), were hydrothermally synthesized and structurally characterized. Compounds 1-3 feature a corrugated lanthanide arsonate layer, in which 1D lanthanide arsonate inorganic chains are further interconnected via bridging L(1)(3-) ligands. Compounds 4-6 exhibit a complicated 3D network. The interconnection of the lanthanide(III) ions by the bridging arsonate ligand leads to the formation of a novel 3D framework with long narrow 1D tunnels along the a-axis, with the oxalate anions are located at the above tunnels and bridging with lanthanide(III) ions. Compounds 2 and 4 exhibit the characteristic emission bands of the Nd(III) ion, whereas compound 6 displays the characteristic emission bands of the Eu(III) ion. The magnetic properties of compounds 3-6 were also investigated.     

卟啉基超交联聚合物的合成及其对二氧化碳和汞(Ⅱ)离子的吸附北大核心CSCD

超交联聚合物(HCPs)具有较高的比表面积和独特的孔结构,且制备方法简单、合成原料广泛,是多孔有机聚合物的研究热点之一。卟啉是一类由4个吡咯类亚基的α-碳原子通过次甲基桥互联形成的大分子杂环化合物,可与多种金属形成稳定的配合物,在重金属的吸附与检测、气体的吸附与分离等方面具有很好的应用。卟啉结构的HCPs也有了较多的报道,然而当前报道的卟啉结构HCPs几乎均是通过Friedel-Crafts烷基化反应构筑的。Friedel-Crafts酰基化反应在卟啉结构HCPs上报道较少。而通过Friedel-Crafts酰基化反应制备的聚合物表面含大量羰基,为其进一步功能化提供了可能。但是,这类聚合物的比表面积低、孔结构差,而其优良孔结构的构建是亟待解决的问题。为此,本文在四苯基卟啉与1,2,4,5-苯四甲酸酐通过Friedel-Crafts酰基化反应制备的聚合物的基础上,进一步通过席夫碱反应,用含刚性三嗪环的三聚氰胺将其进一步交联,合成了三聚氰胺修饰的卟啉基超交联聚合物。结果发现,三聚氰胺的引入不仅实现了超交联聚合物孔结构的支撑,使得聚合物比表面积极大增长(从2 m^(2)/g增加到118 m^(2)/g),且具有优良的多级孔结构。三聚氰胺修饰卟啉基超交联聚合物的高氮质量分数(46.28%)和多级孔结构使其对CO_(2)(93 mg/g,273 K,101 kPa)和Hg^(2+)(494.1 mg/g,298 K)具有较好的吸附。     

4个Cd(Ⅱ)配位聚合物:辅助配体对晶体结构以及荧光性能的影响

采用溶剂热的方法,将配位模式丰富的多羧酸有机配体5-（2-硝基-4-羧基苯氧基）-间苯二甲酸（H₃ncpoi）与Cd²⁺离子以及不同的辅助配体原位组装而成4个新的配位聚合物晶体：[Cd（Hncpoi）（2,2''-bpy）（H₂O）]_n（1）,{[Cd₂（Hncpoi）₂（bpyp）（H₂O）₄]·3H₂O}_n（2）,{[Cd₂（Hncpoi）₂（azpy）（H₂O）₂]·2H₂O}_n（3）,{[Cd₂（Hncpoi）₂（dpe）（H₂O）₂]·2H₂O}_n（4）,其中H₃ncpoi为5-（2-硝基-4-羧基苯氧基）-间苯二甲酸,2,2''-bpy为2,2''-联吡啶,bpyp为1,4-二-吡啶基-4-亚甲基-哌嗪,azpy为4,4''-偶氮吡啶,dpe为1,2-二-（4-吡啶基）乙烯。对4个配合物进行了X射线单晶衍射、粉末衍射,元素分析、热重、荧光光谱等表征。X射线单晶结构分析表明,配合物1,2具有一维链状结构,而配合物3,4则具有二维（4,4）格子层状结构,一维链和二维层之间通过分子间作用力连接成三维超分子结构。进一步研究表明,辅助配体的构型、配位方式等对晶体结构具有决定性作用。与此同时,对几个配合物的荧光光谱进行分析,发现不同的辅助配体对配合物的荧光性能有着显著的影响。     

Adsorption characteristics of poly(styrene-co-divinylbenzene) resin functionalized with methoxy and phenoxy groups for phenol

Two macroporous crosslinked poly(styrene-co-divinylbenzene) resins functionalized with methoxy and phenoxy groups, PVBME and PVBPE were prepared and their adsorption characteristics for phenol were studied in hexane as well as in aqueous solution. It was shown that the equilibrium adsorption capacity of phenol onto PVBPE was a little larger than that onto PVBME at the same temperature and equilibrium concentration. The adsorption onto PVBME in hexane can be correlated to Langmuir isotherm model, whereas the semi-empirical Freundlich isotherm model characterized the adsorption onto PVBPE better. The adsorption thermodynamic parameters were calculated and it was found that the adsorption enthalpy, adsorption free energy, and adsorption entropy were all negative, and the adsorption thermodynamic parameters onto PVBPE were more negative than the corresponding ones onto PVBME. The relationship of the adsorption capacity with the equilibrium concentration was linear in aqueous solution. The adsorption was hypersensitive to the solution pH in aqueous solution, and the optimum pH was determined to be 6.0. The adsorption dynamics of phenol onto PVBPE in aqueous solution was investigated and it was seen that the adsorption can be well fitted by the pseudo-first-order rate equation.     

电子背散射衍射法研究马氏珠母贝珍珠层中文石择优取向

贝壳珍珠层中的文石相对于在自然环境中生长的文石来说具有更优异的力学性能,这种力学性能取决于其独特的晶体排布方式。通过电子背散射衍射(EBSD)技术获得了马氏珠母贝中不同文石的结晶学取向信息,结果表明珍珠层中文石晶体的c轴均垂直于珍珠层层面,而a、b轴在平行珍珠层方向上具有两级取向畴结构:在初级畴结构内,相邻畴绕c轴偏转,导致不同畴之间a轴或b轴的取向差约64°。在次级畴结构内,文石板片围绕c轴偏转,导致不同畴之间a轴或b轴取向差在10°或20°左右。这种畴结构为我们认识珍珠层中文石的生长机理提供了有益线索。     

Flame quenching process in cavity based on model scramjet combustor

The flame quenching process in combustors was observed by high speed camera and Schlieren system, at the inflow conditions of Ma = 2.64, T 0 = 1 483 K, P 0 = 1.65 MPa, T = 724 K and P = 76.3 kPa. Changing process of the flame and shock structure in the combustor was clearly observed. The results revealed that the precombustion shock disappeared accompanied with the process in which the flame was blown out and withdrawed from the mainflow into the cavity and vanished after a short while. The time of quenching process was extended by the cavity flame holder, and the ability of flame holding was enhanced by arranging more cavities in the downstream as well. The flame was blown from the upstream to the downstream, so the flame in the downstream of the cavity was quenched out later than that in the upstream.     

Experimental investigation of combustion mechanisms of kerosene-fueled scramjet engines with double-cavity flameholders

A scramjet combustor with double cavitybased flameholders was experimentally studied in a directconnected test bed with the inflow conditions of M = 2.64,Pt = 1.84 MPa,Tt = 1 300 K.Successful ignition and selfsustained combustion with room temperature kerosene was achieved using pilot hydrogen,and kerosene was vertically injected into the combustor through 4×φ 0.5 mm holes mounted on the wall.For different equivalence ratios and different injection schemes with both tandem cavities and parallel cavities,flow fields were obtained and compared using a high speed camera and a Schlieren system.Results revealed that the combustor inside the flow field was greatly influenced by the cavity installation scheme,cavities in tandem easily to form a single side flame distribution,and cavities in parallel are more likely to form a joint flame,forming a choked combustion mode.The supersonic combustion flame was a kind of diffusion flame and there were two kinds of combustion modes.In the unchoked combustion mode,both subsonic and supersonic combustion regions existed.While in the choked mode,the combustion region was fully subsonic with strong shock propagating upstream.Results also showed that there was a balance point between the boundary separation and shock enhanced combustion,depending on the intensity of heat release.