Synthesis and properties of two series of H-bonded and non-H-bonded thermotropic liquid crystal monomers

Two series of monomers, namely n-1-bromo-(4-(4-nitrophenylazo)phenyloxy]alkanes (Bn, n = 2, 3, 4, 5, 6, 8, 10) and N-n-[4-(4-nitrophenylazo)phenyloxy]alkyl diethanolamines (Cn, n = 3, 5, 6, 10), were synthesized and characterized. Their thermal behaviour was studied by differential scanning calorimetry (DSC), wide angle X-ray diffractometry (WAXD) and polarizing optical microscopy (POM) equipped with a hot stage. The results showed that the Bns (n greater than or equal to 6) exhibit monotropic nematic liquid crystalline behaviour; no liquid crystalline phase was found for the Bns (n < 6), while for the Cns, enantiotropic smectic liquid crystallinity for n = 5, 6, 10 was seen, and for n = 3 monotropic smectic phases were found. This different phase behaviour between Bn and Cn compounds is attributed to their different end groups. The FTIR analysis of Cn indicated that there exists an intermolecular hydrogen bond between hydroxy groups, so that more stable liquid crystalline phase are formed. The effect of the length of the flexible chain on the thermal behaviour is also discussed.

Ge-132与稀土离子的配合物及其对单核苷酸磷酯键的催化水解作用

Ge－132的羧酸阴离子与稀土离子螯合配位，生成3：1型配合物。在配合物中，Ge－132的GeO3/2基因水解为Ge（OH）3，并且不参与稀土配位，系列稀土离子配合物的结构性质基本相同，在50℃，pH值为6的水溶液中，该配合物选择性地催化5’－AMP或5’－dAMP的磷酯键水解断裂，生成相应的核苷和磷酸，而不影响碱基与戌糖之1间的苷键。

聚氯乙烯-尼龙6树脂分离富集碘量法测定金精矿中金

采用聚氯乙烯尼龙６树脂分离富集溶解于王水中的金精矿样品中的金，然后用乙二胺溶液洗脱，并用碘量法测金。经标样验证，结果令人满意。

Luminescence properties of sol-gel derived silica gels doped and undoped with RE-complexes (RE=Eu, Tb)

The luminescence properties of silica gels and silica gels doped with two rare earth complexes, Eu(TTA)(3) and Tb(o-CBA)(3) (TTA=thenoyltriffuocetate, o-CBA=o-chlorobenzoic acid) are reported and discussed. Pure silica gels show a blue luminescence, and the maximum excitation and emission wavelengths depend strongly on the solvents used. Both of the studied rare earth complexes exhibit the characteristic emissions of the rare earth ions in silica gels, i.e., Eu3+5D0-->F-7(J)(J=0,1,2,3,4), Tb3+5D4-->F-7(J)(J=3,4,5,6) transitions. Compared with the pure RE-complexes powder, the silica gels doped with RE-complexes show fewer emission lines of the rare earth ions. Furthermore the rare earth ion (Tb3+) presents a longer lifetime (1346 mu s) in silica gel doped with Tb(o-CBA)3 than in pure Tb((o-CBA)(3) powder (744 mu s). The reasons responsible for these results are discussed in the context.

Rapid automated in-situ monitoring of total dissolved iron and total dissolved manganese in underground water by reverse-flow injection with chemiluminescence detection during the process of water treatment

Measurement of iron and manganese is very important in evaluating the quality of natural waters. We have constructed an automated Fe(II), total dissolved iron(TDI), Mn(II), and total dissolved manganese(TDM) analysis system for the quality control of underground drinking water by reverse flow injection analysis and chemiluminescence detection(rFIA-CL), The method is based on the measurement of the metal-catalyzed light emission from luminol oxidation by potassium periodate. The typical signal is a narrow peak, in which the height is proportional to light emitted and hence to the concentration of metal ions. The detection limits were 3 x 10(-6) mu g ml(-1) for Fe(II) and the linear range extents up to 1.0 x 10(-4) and 5 x 10(-6) mu g ml(-1) for Mn(II) cover a linear range to 1.0 x 10(-4) mu g ml(-1). This method was used for automated in-situ monitoring of total dissolved iron and total dissolved in underground water during water treatment. (C) 1997 Elsevier Science B.V.

对氨基二乙基苯胺全差示光度法测定微量铬

详细实验了铬（Ⅵ) 与对氨基二乙基苯胺氧化显色反应的条件。实验结果表明：铬（Ⅵ）与对氨基二乙基苯胺反应形成的红色产物在 554 nm处有最大吸收。表观摩尔吸收系数为 3．3 × 104L·mol-1·cm-1；线性范围为0～1.6 mg／L。实验了采用全差示光度法测定水中铬的条件，用于某湖水中 4．07 μg/L的铬测定时，相对标准偏差为 3．4％（n=6）。测定结果与二苯胺基脲法的测定结果相比令人满意。

一些双官能团苯基醚化合物的离子/中性复合物中间体质谱碎裂

报道了3种含双官能团苯基醚化合物2－（2，6－二氯苯氧基）丙睛、N－羟基－4－丁氧基苯乙酰胺、2－（1－甲基乙氧基）苯酚甲氨基甲酸酯的电子轰击质谱碎裂．用亚稳分析和低能碰撞诱导解离研究了3种化合物的分子离子碎裂规律，除简单的直接键断裂外，还证实经历了离子／中性（碎片）复合物中间体的单分子解离反应同时存在的竞争机理，解释了观察到的分子内单氢迁移、双氢迁移现象.

4-羟基偶氮苯与6-氯-5,12-萘并萘醌反应产物的NMR分析

无水碳酸钾存在下6-氯-5,12-萘并萘醌与4-羟基偶氮苯在干燥DMF中反应的主要产物在某些反应条件下不是6[4-(苯基偶氮基)苯氧基]-5,12-萘并萘醌(1)。该未知反应产物2经核磁共振方法研究证实是6-(N,N-二甲氨基)-5,12-萘并萘醌。本文对化合物2的~1H-和~(13)C化学位移、偶合信息和结构作了详细归属,并推测其反应进程,实验结果表明,化合物2是由化合物1与溶剂DMF反应生成。

Gas permeation properties of cardo polyaryletherketones containing different alkyl substituents

The gas permeation properties of a series of cardo polyaryletherketone materials are reported, In this series, the hydrogen atoms of benzene rings on the backbone are systematically replaced with different alkyl substituents. The effects of temperature and structure variation on gas permeability and selectivity are discussed in detail. The experimental results revealed that the polyetherketone obtained by the introduction of dimethyl and diisopropyl substituents to phenolphthalein unit is 3 similar to 6 times more permeable than the unmodified one for the gases studied.

Synthesis and thermal transitional properties of side-chain liquid crystalline polyacrylates containing para-nitroazobenzene as mesogenic groups

The synthesis and characterization of side-chain liquid crystalline (LC) polyacrylates containing para-nitroazobenzene (Pn) as mesogenic groups were described. Homopolymers with 3 and 4 carbon atoms in the spacers were non-LC polymers; for homopolymers with 6 carbon atoms in the spacer, nematic LC behavior was observed. Copolymers with acrylic acid as one component exhibited an S-Ad phase according to the WAXD results which showed the d/l of 1.4-1.54 for the copolymers with 3, 4, and 6 carbon atoms in the spacers. Considering the molecular structure as well as the WAXD results of the copolymers, the possible molecular arrangement in the smectic Sad phase was proposed, in which the smectic layers were composed of the antiparallel mesogens and the antiparallel arrangement was considered to be enhanced due to the H bond between - COOH and - NO2. The stress-induced orientational phenomena of Pn in the LC states was also discussed. (C) 1996 John Wiley & Sons, Inc.

稀土氧化钕填充尼龙6体系的流变行为研究

用锥板粘度仪测试仪测试了稀土氧化钕（Ｎｄ２Ｏ３）填充尼龙６体系的流变行为，填充体系的熔融粘度明显低于空白尼龙６，体系的粘度随稀土氧化物含量的增加而降低，填充后试样具有良好的流动性和加工稳定性。

双环己基18冠6对水/硝基苯界面离子的促进传输

Li~-和H~-因较强的亲水性,较难穿越液/液界面进行传输。本文报道了冠醚双环已基18冠6对Li~+,Na~+,Rb~-和H~-在水/硝基苯界面的促进传输行为,求得了相应促进传输过程的一系列参数,并对被传输离子在传输过程中的形态变化进行了初步的探讨。

尼龙6,6(PA_(6,6)及其共混物结晶性能的研究

尼龙6,6(PA_(6,6))是一种典型的结晶性工程塑料,被广泛应用于纺织、机械制造等行业,但其加工温度范围较窄,耐热性差。聚醚砜(PES)具有较高的玻璃化转变温度,是非晶聚合物,可以诱发某些结晶聚合物结晶。PES与PA_(6,6)共混体系的研究报道较少,本文用熔融法将PES与PA_(6,6)制成共混物,企图改善PA_(6,6)的结晶性,以提高其耐热性,取得了较理想的结果。

稀土-其它过渡金属混合催化剂用于共轭双烯烃的聚合——Ⅳ.(NdCl_3+FeCl_3)·nphen-HAI(i-Bu)_2体系对异戊二烯的聚合

本文报道由(NdCl_3+FeCl_3)·nphen-HAl(i-Bu)_2催化体系引发异戊二烯聚合的结果。在适当Nd/Pe比下,该体系对异戊二烯聚合的活性可超过单一钕或铁催化剂的活性,同时随催化剂中钕和铁含量的不同,所得产物的微观结构变化很大,当体系中钕含量由100％→0时,产物的顺-1,4结构含量由94.4％→22.1％,而3,4结构含量由5.6％→77.9％。Al/M(N=Nd+Fe)比、单体浓度和聚合温度不仅对聚合活性有影响,对产物的微观结构影响也较大。事实表明,该聚合体系中存在着两种过渡金属(Nd和Fe)活性中心,它们按各自的机理进行异戊二烯的聚合。

中国红参中碳、氢、氮元素和蛋白含量的自动分析

人参为五加科植物人参(Panax ginseng C.A.Mey.)的干燥根。红参则是鲜人参洗净后经高温蒸气加热后干燥而制得的产品。有关人参中皂甙、氨基酸、多肽、挥发油、微量元素等成分的研究国内外均有大量的报道。但关于红参中碳、氢、氮元素的研究以及自动定量方法国内外尚未见报道。 1.仪器:1106型元素自动分析仪(意大利)其配套设备包括B-5000型记录仪,微处理机和电子天平。 2.人参样品:1号红参由吉林省抚松县参茸公司提供。2号红参由抚松县漫江参场提供。3号红参为抚松县参场提供。4号红参由延边地区提供。5号红参由集安县新开河参场提供。上述样品均为6年生。