天然绿色棉花的固体核磁共振表征

近年来,用天然彩色棉花作为纺织原料制成的服饰因具有环保优势而受到越来越多消费者的青睐.为建立鉴别真假天然彩棉的方法,有必要对天然彩棉和普通棉花的结构进行比较研究.本文利用高分辨固体核磁共振(NMR)对天然绿色棉花(以下简称天然绿棉)和普通白色棉花(以下简称普通白棉)中纤维素的聚集态结构与分子链的运动能力等进行了表征.     

高聚物亚浓溶液区标度律的蒙特卡洛模拟

利用蒙特卡洛模拟方法对线形链和星形键在亚浓溶液区的标度律作了验证与讨论。我们的计算结果证明线形链渗透压Π与体积分数Φ在亚浓溶液区的标度规律是与德热纳的理论结果相一致的。同时还证明了星形链在亚浓溶液区具有与线形链相同的标度行为。     

预辐照聚三氟氯乙烯薄膜接枝苯乙烯的研究

预辐照聚三氟氯乙烯薄膜的过氧化含氟自由基室温衰变缓慢,可长期生存。预辐照的有效期可超过六年,研究了苯乙烯接枝反应时的温度、无机盐添加剂和有机溶剂的影响。观察到较低温度能提高接枝率。添加三氯化铁能有效地抑制苯乙烯自聚反应,并研究了聚三氟氯乙烯-苯乙烯接枝共聚物的结构特征。     

Paleomagnetic Results of Later Paleozolic Rocks From Alashan Area of Western North China Block

In order to contribute to the Apparent Polar Wander Path (APWP) of the North China Block (NCB) , we collected paleomagnetic samples of Late Paleozoic rocks from the northern and southern margins of the Alashan (Alxa) terrane (the western part of Inner Mongolia and northern parts of Gansu and Ningxia Provinces) and adjacent regions. Laboratory work revealed different types of demagnetization behavior and isolated a higher temperature characteristic component in most of the samples. Results of IRM experiments show high thermal stability and high coercivities for the magnetic carriers in these rocks. The characteristic component passed the fold and/or reversal tests, suggesting that the characteristic components were probably primary. On the basis of comparing the paleomagnetic results with the geologic evidence, we discuss the tectonic implications. In the Late Paleozoic, the Alashan region had been part of the NCB and was not connected with the northern and southern blocks. During the Carboniferous Alash     

NOx在固体电解质电解池上的电化学消除

 综述了近年来利用固体电解质电解池消除NO的研究进展．重点总结了电化学消除NO研究体系、电化学消除NO分解机制、O2－在固体电解质电解池中传导的控速步骤、电极种类和形态对NO分解性能的影响以及直流与交流电作用的差异等几个方面的研究结果．在RuO2—Ag—YSZ—Pd电解池上实现的NO选择性分解是迄今为止的最佳结果，500℃下NO的转化率为31．8％，NO的分解活性是O2的分解活性的13倍．该领域今后研究的主要方向是，进一步提高NO分解相对于共存O2离子化的选择性、降低O2－在阴极界面处的传导阻力和探寻可在更低温度传导O2－的新的固体电解质     

溴原子取代对二茂铁液晶化合物介晶性的影响

二茂铁液晶因其独特的稳定性和易于衍生化受到研究人员的青睐[1- 8] 。我们曾经报道过一类单取代二茂铁液晶的合成与介晶性[9] 。这里我们报道另外一类二茂铁单取代液晶 ,并对分子的长度、溴原子取代对介晶性的影响进行探讨。合成路线如下 :1　实验部分ＢｒｕｃｋｅｒＡＣＥ -2 0 0ｓｐｅｃｔｒｏｍｅｔｅｒ,ＣＤＣｌ3作溶剂。ＮｉｃｏｌｅｔＭａｇｎａ-ＩＲ 5 0 0Ｓｐｅｃｔｒｏｍｅｔｅｒ,ＳｅｒｉｅｓⅡ ,ＫＢｒ压片。ＷＲＳ -ＩＡ ,ＣａｒｌｏＥｒｂａ 1 1 0ｂ。Ｐｅｒｋｉｎ -Ｅｌｍｅｒ 7Ｓｅｒｉｅｓ热分析仪 ,分温速度 1 0℃ /ｍｉ…     

Ultraviolet photolysis of CH2I2 in methanol: O-H insertion and HI elimination reactions to form a dimethoxymethane product

Ultraviolet photolysis of low concentrations of CH2I2 in methanol solution found that CH2I2 is converted into dimethoxymethane and some H+ and I- products. Picosecond time-resolved resonance Raman (ps-TR3) experiments observed that the isodiiodomethane (CH2I-I) photoproduct decayed faster as the concentration of methanol increases, suggesting that isodiiodomethane is reacting with methanol. Ab initio calculations indicate isodiiodomethane is able to react with methanol via an O-H insertion/HI elimination to form an iodoether (ICH2-O-CH3) and HI products. The iodoether can then further react via another O-H insertion/HI elimination reaction to form the dimethoxymethane (CH3-O-CH2-O-CH3) observed in the photochemistry experiments. A reaction mechanism consistent with these experimental and theoretical observations is proposed.     

The anion sequence in the phase transformation of mesostructures templated by non-ionic block copolymers

A p6m to Ia3d mesophase evolution is achieved by simply adjusting the acidity and/or anion species in the presence of block copolymers; the unusual anion sequence that affects the phase behavior of block copolymer templated mesostructured solids is revealed to be SO(4)(2-)(HSO(4)(-)) > NO(3)(-) > Br(-) > Cl(-).