碱性矿化水灌溉对土壤溶质运移的影响

经过连续几年的灌溉试验可知,应用2.5 g稬-1以下的低矿化水灌溉是安全的,超过此值土壤积盐和碱化明显。灌溉后,土壤中溶质运移受多因素影响。在阳离子分布中,水平方向Na+随灌溉水矿化度增大而增多,Ca2+、Mg2+变化不大;土壤剖面上,从表层至60 cm土层,先以Ca2+、Mg2+为主,过渡到Na+、Ca2+、Mg2+共同占优,再发展为以Na+占优。阴离子的分布中,水平方向,随灌溉水矿化度增大HCO3-增多;土壤剖面上,从表向里,先以Cl-或SO42-为主,过渡到C1-、SO42-、HCO3-均分局面,再发展以HCO3-占优。灌溉后土壤pH值在0~20 cm变化不明显,大于20 cm土层有一定增加。土壤中的SAR和ESP均以大于1.5 g稬-1的碱性低矿化水灌溉后增加明显,碱化层由下向上抬升,小麦田碱化速度快于玉米田。

无机阴离子对镉、铅解吸特性的影响

土壤中重金属的解吸直接影响重金属在环境中的形态转化和植物有效性。而地表水环境及土壤中的无机阴离子能与重金属离子络合,影响重金属在环境中的迁移和作物的吸收。因此,有关无机阴离子对重金属解吸特性影响的研究,将有利于了解重金属的吸附-解吸机制及其控制措施。文章以我国东北地区草甸棕壤作为研究对象,采用静态解吸实验研究无机阴离子(C1-、SO42-、F-)对土壤中镉、铅的解吸行为的影响。结果表明,土壤中镉、铅的解吸率与无机阴离子类型、浓度密切相关;随着解吸液中无机阴离子(C1-、SO42-、F-)浓度的增大,土壤镉、铅的解吸率随之提高。C1-、SO42-、F-这3种无机阴离子对解吸土壤中镉的影响力顺序是:C1->SO42->F-;对解吸土壤中铅的影响力顺序是:SO42->C1->F-。

有机酸无机离子对土壤镉铅解吸特性的影响

为深入了解草甸棕壤中镉、铅的解吸行为,采用一次平衡法探讨有机酸、无机离子对镉、铅解吸特性的影响。结果表明,柠檬酸、草酸、组氨酸摩尔浓度较低时,有机配位体抑制镉的释放,而有机酸摩尔浓度较高时(>2 mmol·L-1)将明显促进镉的释放。柠檬酸、草酸、组氨酸对Pb的解吸率随有机酸摩尔浓度提高(0-20 mmol·L-1)而增大,对Cd、Pb浸提能力的大小关系为:柠檬酸﹥草酸﹥组氨酸。随解吸液中无机离子(C1-、SO42-、F-)摩尔浓度的增大,镉、铅的解吸率亦随之提高。无机离子对解吸土壤中Cd的影响力顺序是:C1->SO42->F-;对解吸土壤中Pb的影响力顺序是:SO42->C1->F-。

Temperature and pressure dependence of phase separation of trans-decahydronaphthalene/polystyrene solution

The cloud-point temperatures (T-c1's) of ti-ans-decahydronaphthalene (TD)/polystyrene (PS, M-w = 270 kg/mol) solutions were determined by fight scattering measurements over a range of temperatures (1-16 degreesC), pressures (100-900 bar), and compositions (4.2-21.6 vol% polymer). The system phase separates upon cooling and the T-c1 was found to increase with the rising pressure for the constant composition. In the absence of special effects this finding indicates positive excess volumes. The special attention was paid to the demixing temperatures as a function of the pressure for the different polymer solutions and the plots in the T-volume fraction plane and P-volume fraction plane. The cloud-point curves of polymer solutions under changing pressures were observed for different compositions, demonstrates that the TD/PS system exhibits UCST (phase separation upon cooling) behavior. With this data the phase diagrams under pressure were calculated applying the Sanchez-Lacombe (SL) lattice fluid theory. Furthermore, the cause of phase separation, i.e., the influence of Flory-Huggins (FH) interaction parameter under pressure was investigated.

添加元素对AB_2型Laves相合金电化学性能的影响

比较系统地研究了 AB2 型 Laves相合金 Zr0 .9Ti0 .1Ni0 .1Mn0 .7V0 .3 M0 .1( M=None,Ni,Mn,V,Co,Cr,Al,Fe,Mo,Si,C,Zn,Cu和 B)的相结构和电化学性能以及高温和低温放电性能等 .结果表明 ,1 4种合金均具有六方 C1 4型 Laves相的主相晶体结构 ,同时 ,含有少量立方 C1 5型 Laves相和一些由 Zr.9Ni11及 Zr Ni组成的非 Laves相 ;添加 V和 Mn可提高 AB2 合金的放电容量 ;添加 B和 Mn则显著提高了 AB2 合金的高倍率放电性能和低温放电容量 ;添加 Al,C,Si和 Co对合金电极的循环稳定性改善明显 ;而 Mn,Ni,V,Fe,Cu,Mo和 B等却不同程度地降低了循环稳定性 ;添加 Si,Mo,V,Cr和 Al可明显改善合金电极的自放电性能 ;添加 Si,Cr,V可显著改善 AB2 合金电极的高温放电性能 .讨论了各种添加元素影响合金性能的可能原因.

四逆汤煎煮过程中乌头类生物碱的溶出和水解平衡

目的　研究四逆汤中乌头类生物碱的溶出平衡和水解平衡。方法　利用电喷雾质谱分析 ,比较了制附子、四逆汤、四逆汤药渣和含有 3种双酯型生物碱的混合对照品体系中的乌头碱类二萜生物碱。结果　在煎煮过程中双酯型生物碱溶解并发生水解反应 ,而脂类生物碱则难溶于水。乌头碱、中乌头碱、次乌头碱水溶性相近 ,但是次乌头碱在水中的热稳定性更高 ,C1 9二萜骨架上 C3取代基 ( - OH或 - H)的变化影响生物碱的稳定性。结论　四逆汤中的乌头碱类生物碱的种类及含量由其溶解性和化学稳定性共同决定。

Cyclization in situ of isoprene polymerization catalyzed by Nd-Al bimetallic complex

Function of chloride and effect of various alkylaluminiums, C1/A1 molar ratio, solvents on cyclization in situ of isoprene polymerization catalyzed by Nd-Al bimetallic complex were studied. The structure of cyclized products was characterized by means of IR and H-1 NMR, The results indicated that in the course of isoprene polymerization with rare earth catalytic system, the function of alkylchloride introduced is terminating cis-polymerization and generating cationic species with alkyl-aluminums to initiate cyclization in situ. Soluble cyclized polyisoprene was obtained with fragments of cyclopolyisoprene.

胺类化合物气相色谱保留指数与结构的相关性研究

应用Am指数和引力指数C1对在3种体系下的胺类化合物的气相色谱保留指数和结构进行了相关性研究，并运用最佳子变量集算法和人工神经网法进行了计算分析，在非极性固定相OV-101和极性固定相OV-225和NGA下均获得了比较好的相关模型。

梳状聚合物电解质的力学松弛时间

以苯乙烯 /马来酸酐共聚物为骨架 ,聚乙二醇单甲醚为侧链合成了 3种不同侧链长度的梳状高分子聚合物 ,制成了锂盐络合物薄膜 .动态力学性能研究结果表明 ,本体系是主链刚性、侧链较柔软的梳状接枝聚合物 .应用时间温度等效原理 ,选择Tα 作为参考温度 ,建立了主曲线 ,得到了移动因子图和等自由体积图 .Williams、Landel和Ferry(WLF)经验方程的两个参数C1、C2 随着盐浓度增加而增大 .若T0 =50℃作为参考温度 ,平均松弛时间lgτc 与锂盐浓度C呈线性关系 .随着侧链分子量增加 ,主曲线向高频率移动 ;平均松弛时间lgτn 与侧链分子量的关系也是线性的 ;另外随着盐的不同 ,主曲线也会产生移动 ,表明盐种类对松弛时间产生影响.

吲哚酚衍生物的结构-式电位关系及电氧化机理

以半经验分子轨道方法计算吲哚酚衍生物的分子结构参数.以主因子分析法和多元线性回归法研究了吲哚酚衍生物的式电位与其分子结构参数间的关系.研究发现,在所选择的19个分子结构参数中,双中心电子交换能(Eex(2)/eV),O -C键的共振能(Er(C1-O)/eV)和分子的电离势(Ip/eV)与其式电位有较好的相关性.其回归方程为:y=1.47×10-3Eex(2) -5.74×10-2 Er(C1-O) -1.41×10-2Ip(RC=0.9999,SD=0.00424).由分子结构与式电位关系及中间产物的稳定性可推测,在吲哚酚的氧化机理中氢的电离反应优先于电子转移过程.

Hydrothermal synthesis and crystal structure of Co(En)(3)MoO4

Co(En)(3)MoO4 was synthesized by using the method of hydrothermal synthesis and characterized by elemental analysis, IR, ESR and single-crystal X-ray methods. It crystallizes in hexagonal space group P (3) over bar C1 with a=1.596 4(2) nm, b=1.596 4(2) nm, c = 0.993 5(2) nm, alpha=beta=90 degrees gamma=120 degrees, M-c=399.18, V=2.192 6(6) nm(3), D-c=1.814 g/nm(3), Z=6, F(000)=1 2181 R-1=0.070 3, R-w=0.220 7. According to separation of anion which acted on electrostatic potential, the anion and cation ions formed a type of organic and inorganic material.

Electrocatalytic oxidation of methanol on polypyrrole film modified with platinum microparticles

The electrocatalytic oxidation of methanol on polypyrrole (PPy) film modified with platinum microparticles has been studied by means of electrochemical and in situ Fourier transform infrared techniques. The Pt microparticles, which were incorporated in the PPy film by the technique of cyclic voltammetry, were uniformly dispersed. The modified electrode exhibits significant electrocatalytic activity for the oxidation of methanol. The catalytic activities were found to be dependent on Pt loading and the thickness of the PPy film. The linearly adsorbed CO species is the only intermediate of electrochemical oxidation of methanol and can be readily oxidized at the modified electrodes. The enhanced electrocatalytic activities may be due to the uniform dispersion of Pt microparticles in the PPy film and the synergistic effects of the highly dispersed Pt microparticles and the PPy film. Finally, a reaction mechanism is suggested.

四氯合锌酸二(正十一烷基铵)晶体相变的Raman光谱

用Raman光谱研究了[n-C_(11)H_(23)NH_3]_2ZnCl_4(简记为C_nZn)配合物的固-固相变.结果表明,配合物产生的固-固相变主要与烷烃链的堆积结构和分子构象变化有关.在 T_(c1)=25℃的相变是由于烷烃链的侧向堆积和分子构象的有序到部分无序变化.在中间相,分子链局部产生旁式构象.在T_(c2)=87℃的相变主要来源于烷烃链从部分构象有序到完全无序的变化.高温相形成了构象完全无序相.相应于烷烃链的“熔化”.