下辽河平原潮棕壤稻田的无机态氮淋溶

应用陶土渗滤管法,研究了不同施氮和渗漏条件下潮棕壤稻田的氮淋溶损失。结果表明:稻季各次施用氮肥后,60 cm和90 cm深处渗漏液中NH4+-N含量都小于2 m g/L,并且各施氮肥处理和对照间差别不显著;但硝酸盐淋溶比较显著,多集中在3~15 m g/L之间。硝酸盐淋溶随施氮量增加而增加,90 cm深度渗漏液中这一趋势更为明显。水分渗漏状况影响硝酸盐在不同土层深度的累积:渗水越快,硝酸盐淋溶深度越大。渗水较快或者施氮量高时,硝酸盐的淋溶浓度高于国际饮用水卫生标准10 m g/L。施用基肥后灌水,NH4+-N、NO3--N立即出现高峰,而施用分蘖肥和穗肥后,高峰出现在施肥后10 d或更久;另处基肥时期淋溶氮的浓度也比较高。

我国煤炭省际调运的空间格局演变及其影响

了解我国煤炭省际运输空间格局的演变及其影响,有助于我国煤炭综合运输及能源可持续利用研究。通过对我国1985年以来煤炭省际输出,输入量和省区的空间变化及社会和环境影响分析,研究发现近20年来我国煤炭省际调运的空间格局发生了明显变化。全国省际煤炭输出和输入量迅速增长,输出和输入的不均匀程度稍有减小。输出省区向西、向北偏移,输入省区向东南方向偏移。在主要的煤炭净输出省区中,山西一直居于主导地位,但是内蒙古和陕西省的影响力逐渐增强：分散的区域性煤炭输出省区影响范围不断萎缩,输出量向邻近省区集中。我国煤炭省际运输空间格局的演变带来了一些社会和环境影响,煤炭省际运输量和运输距离的增加不仅带来了更为严重的环境和生态影响,也为我国东西部地区的协调发展带来了挑战,并对我国能源安全带来了更多的隐患。

龙胆质谱指纹图谱及化学模式识别方法研究

利用电喷雾质谱(ESI-MS)法建立龙胆质谱指纹图谱,研究其中代表性裂环烯醚萜苷类成分的ESI-MS规律。采用甲醇超声法提取龙胆中裂环烯醚萜苷类成分,在正离子方式检测模式下直接进样,应用一级全扫描质谱建立其特征图谱。运用化学模式识别方法对图谱数据进行分析,发现秋季龙胆样品的聚集程度优于春季龙胆样品,根据春季、秋季药材样品的差异,可以对采收期进行区分;裂环烯醚萜苷类成分在二级质谱中易发生脱水、乙酰基、葡萄糖基等。电喷雾质谱法的精密度、稳定性、重现性均符合要求,且具有特征性强、分析速度快、样品用量少等优点。

A novel 2D arsenic vanadate network grafted with a transition metal complex: [Cu(phen)][(VV4As2O19)-V-IV-As-V]center dot 0.5H(2)O

A novel organic-inorganic hybrid compound [Cu(phen)](2)[(VV4As2O19)-V-IV-As-V-O-V].0.5H(2)O 1 has been hydrothermally synthesized. Its structure, determined by single crystal X-ray diffraction, exhibits an unusual two-dimensional arsenic vanadate layered network grafted with the [Cu(phen)](2+) complex. The chelating phen ligands project perpendicularly beyond the inorganic layer. Variable temperature magnetic susceptibility studies indicate that both ferro- and antiferro-magnetic interactions exist in 1.

Synthesis and luminescence properties of oxyapatite NaY9Si6O26 doped with Eu3+, Tb3+, Dy3+ and Pb2+

Oxyapatite NaY9Si6O26 was prepared by sol-gel method. By choosing the precursors, a single phase compound was obtained. This soft chemical method lowered the reaction temperature by 100degreesC compared with the solid state method. Its morphology was studied by transmission electron microscopy (TEM). Several rare earth ions (Eu3+, Tb3+, Dy3+) and Pb2+ ion were doped in this compound. The high resolution emission spectrum of Eu3+ showed that rare earth ions occupied two yttrium sites. In spite of the charge imbalance of Pb2+ with the cations in this compound, it was found that Pb2+ could emit in UV range and transfer its excitation energy to Dy3+ ion.

VUV excited luminescence of europium activated calcium borophosphate prepared in air

XAFS (EXAFS and XANES) at Eu-L-3 edge were used to determine the local structure and the valences of europium in CaBPO5:Eu prepared in air. The results of EXAFS showed that the doped europium atoms were nine-coordinated by oxygen atoms and the distances of bond Eu-O were 2.39 Angstrom in the host lattice. XANES at Eu-L-3 edge exhibited that Eu2+ and Eu3+ coexisted in the matrix. The luminescent spectrum of the material excited by VUV at 147 nm presented a similar spectrum with that excited by f-f transition of Eu2+ at 396 nm and f-d transition of Eu2+ at 312 nm. The broad emission band due to both 4f(6)5d - 4f(7) transition of EU2+ and f - f transition of Eu3+ could be observed in emission spectra, which indicated that the trivalent europium ions were reduced in air in the matrix at high temperature by the defects [V-Cn]" formed by aliovalent substitution between Ca2+ and Eu3+ ions. The UV excitation spectrum showed the typical f-f transition of Eu3+ and f-d transition of Eu2+. The bands with the maxima at about 113 and 158 nm in VUV excitation spectrum were assigned to originate from the absorption of the host lattice.

LaNi2和LaNi2.28储氢电极性能研究

在真空电弧炉内制备了LaNi<,2>和LaNi<,2.28>合金,在超高压下处理LaNi<,2>合金,得到了具有Laves相结构的AB<,2>型金属间化合物,采用机械合金化装置对上述铸造合金进行了球磨处理,制备了LaNi<,2.28>非晶合金粉末.利用这些合金制备储氢电极,与烧结镍阳极组成单电池,研究各种电极的充放电性能,得到如下结论:(1)LaNi<,2>和LaNi<,2.28>铸态合金电极的放电容量分别为199.4mAh/g和241.0mAh/g;(2)铸态AB<,2>合金的循环性能和放电容量高于Laves相结构的AB<,2>型合金;(3)非晶化的合金电极非常容易被活化,但循环性能和放电容量都远低于铸态合金电极.

Luminescent centers of EU2+ in BaMgAl10O17 phosphor

Two kinds of luminescent centers an observed in BaMgAl10O17:Eu2+ phosphor. Influence of flux on luminescence of Eu2+ in the phosphor is discussed in detail. There exists Eu2+ (F-) center (a luminescent center with 277 nm excitation band and 386 nm emission band) due to the substitution of F- ions for O2- ions, Effective energy transfer from Eu2+ (F-) to Eu2+ (O2-) (a luminescent center with 334 nm excitation band and 450 nm emission band) is observed. The quenching concentration of Eu2+ in BaMgAl10O17 is raised by 0.20 mole per mole host due to forming of new luminescent center Eu2+ (F-). (C) 2001 Elsevier Science Ltd. All rights reserved.

Studies on the structure and properties of thermotropic liquid crystalline poly(aryl ether ketone)s

Series of thermotropic liquid crystalline poly (aryl ether ketone) s were synthesized by mucleophilic substitution reactions of 4,4'-biphenol and substituted hydroquinone with different difluoromonomers, The relationship between structure and properties of the novel copolymers was investigated. For the copolymers with liquid crystalline properties, their melting transition temperatures show no great change with increase the content of the crystal-disrupting unit. The reason is that the crystal phase is directly transformed from the ordered liquid crystal phase. Side-groups have important effect on mesophase stability, The temperature range of mesophase stability for the chloro-polymers is smaller than those of other series of copolymers (P-phenyl, t-butyl, methoxy, 3-trifluoromethylbenzene). This behavior indicates that the effect of geometric repulsive factor on the thermodynamic stability of the mesophase is much larger than that of the polarizability attractive factor. Different ordered liquid crystal phases are observed in the polymers with different molecular weights. At low molecular weight, highly ordered smectic liquid crystal phases form. With increasing the molecular weight, the ordered degree of the liquid crystals decreases, and only the nematic liquid crystal phase is observed in the polymer with higher molecular weight.

液晶聚芳醚酮的结构与性能研究

以联苯二酚、取代对苯二酚及含氟酮单体为原料 ,通过亲核取代反应 ,合成了系列具有液晶性的新型聚芳醚酮 .研究了聚合物分子结构与性能之间的关系 .由于结晶相是从有序的液晶相转化形成的 ,故侧基含量的增加对液晶聚合物的融熔转变温度无显著影响 .聚合物的液晶稳定性受侧基影响较大 ,含极性侧基的氯取代聚合物的液晶温区比含大空阻侧基的聚合物的液晶温区小得多 ,说明空间几何因素比极性因素对液晶稳定性的影响大 .不同分子量聚合物有不同的液晶有序结构 ,低分子量聚合物具有高有序液晶结构 ,而高分子量聚合物只有低有序的向列相结构 .

反向流动注射化学发光法测定痕量铁

基于邻菲啰啉对高碘酸钾－碱性鲁米诺－铁（Ⅲ）体系发光强度的增敏作用建立了水体中总铁的反向流动注射化学发光检测方法。该法线性范围在１×１０－４～１０ｍｇ／Ｌ，检测限为３×１０－６ｍｇ／Ｌ，对于５×１０－３ｍｇ／ＬＦｅ（Ⅱ）测定９次的相对标准偏差为０．９％。此方法已用在水处理中总铁的监测.

Synthesis of lanthanide-alkylaluminium bimetallic complexes and studies on their catalytic activities for polymerization of some polar monomers

Three new lanthanide (Ln)-alkylaluminium (Al) bimetallic complexes with the formula [(mu-CF3CO2)(2)Ln(mu-CF3CHO2)AIR(2) . 2THF](2) (Ln = Nd, Y, R=i-C4H9 (i-Bu); Ln=Eu, R=C2H5(Et); THF=tetrahydrofuran) were synthesized by the reaction of Ln(CF,CO,), (Ln=Nd, Y) with HAI (i-Bu)(2) and of Eu(CF3CO2)(3) with AlEt(3), respectively. Their crystal structures were determined by X-ray diffraction at 233 K. [(mu-CF3CO2)(2)Nd (mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Nd-Al) and [(mu-CF3CO2)(2)Y(mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Y-Al) are isomorphous and crystallize in space group with a=12.441(3) Angstrom [12.347(5) Angstrom for Y-Al], b=12.832(3) Angstrom [12.832(4) Angstrom], c=11.334(3) Angstrom [11.292(8) Angstrom], alpha=104.93 (2)degrees [104.45(4)degrees], beta=98.47(2)degrees [98.81(4)degrees], gamma=64.60(2)degrees [64.30(3)degrees], R=0.519 [0.113], R(w)=0.0532 [0.110], Z=1 and [(mu-CF3CO2)(2)Eu(CF3CHO2)AlEt(2) . 2THF](2)(Eu-Al) in space group P2(1)/n with a=11.913(6) Angstrom, b=14.051(9) Angstrom, c=17.920(9) Angstrom, alpha=101.88(11)degrees, beta=gamma=90 degrees, R=0.0509, R(w)=0.0471 and Z=2. The six CF3CO2- (including CF3CHO2-) of each complex, among which pairs are equivalent, coordinated to Ln and Al in three patterns: (A) the two oxygen atoms in one of the three CF3CO2- type coordinated to two different Ln; (B) the two oxygen atoms in the second of CF3CO2- type coordinated to Ln and Al, respectively; (C) one of the two oxygen atoms in the third CF3CO2- type bidentately coordinated to two Ln and another oxygen coordinated to Al and one of the two Ln, respectively. Unlike types A and B, in type C the carboxyl carbon with a hydrogen atom bonded to it was found to appear as an sp(3)-hybridized configuration rather than an sp(2)-one. 1D and 2D NMR results further confirmed the existence of such a disproportionated CF3CHO2- ligand. Methyl methacrylate (MMA) and epichlorohydrin (ECH) could be polymerized by Y-Al or Eu-Al as a single-component catalyst and highly syndiotactic poly(MMA) was obtained. THF could also be polymerized by Y-Al in the presence of a small amount of ECH.

SYNTHESIS AND CHARACTERIZATION OF TRISUBSTITUTED HETEROPOLYTUNGSTOGERMANATES CONTAINING GROUP 3A ELEMENTS

Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1 as expected for trisubstituted heteropoly anions. The intensity ratio of alpha-Ga compound is 1:2, which is different from others(a:1). With the help of FAB mass spectrum, we concluded that it is a dimer with D-3h structure in aqueous, and the others exist by monomers with C-3v structures.

聚电解质──壳聚糖浓溶液流变学性质研究：浓度、温度、溶剂pH值和外加盐对粘度及流动性的影响

本工作用日本岩本ＲＰＸ－７０５多功能流变仪测定了在不同浓度、温度、溶剂ｐＨ值和外加盐浓度对壳聚糖在甲酸水溶液中其浓溶液粘度η随剪切速率γ的变化关系．讨论了浓度、温度等对溶液粘度、流动活化能Ｅ_γ和流动指数ｎ的影响．发现溶剂ｐＨ值减小或溶液中外加盐浓度增加，溶液粘度变小，ｎ增大，表明非牛顿流动性减弱，并且进一步讨论了零剪切粘度η_０和外加盐浓度Ｃ_ｓ的依赖关系．