杂多酸催化研究新进展

杂多酸催化剂泛指杂多酸及其盐 ,是一类由中心原子 (即杂原子 ,如 P、 Si等 )和配位原子 (即多原子 ,如 Mo、 W等 )通过氧原子桥联方式进行空间组合的多氧簇金属配合物 (polyoxometalate) ,作为催化材料广泛应用于均相与多相催化反应体系 .近年来 ,杂多酸在催化领域中受到越来越多关注 ,主要原因是 :1 .随着石油化工与精细化工的发展 ,催化材料的多功能性成为研究的新目标 .杂多酸是一种酸碱性与氧化还原性兼具的双功能型催化剂 ,对于新催化过程的研究具有重要意义 ;2 .随着分子“剪裁”技术的迅速兴起 ,新型催化材料层出不穷 .杂多酸的阴…     

Synthesis and Properties of New-type Troponoid Dithio-Crown Ethers

Troponoiddithio-crownethersareakindofnovelcomPounds.Takeshitaetall-'havereportedthesynthesisandmercurophilicpropertiesofthiskindofcompounds.lnthereportedcomPounds,thetWosulfuratomsareattached,partorall,tothetroponeringdirectly.Whetherthedithio-crownethersstillhaveselectiveandreversiblemercurysaltcaptUringabi1itywhenthetWosulfuratomslinktothebenZylic-mpepositionoftroponeringarousedourinterest.Herein,wewishtoreportthatfromthereactionof3,7-dichloromethyl-5-isopropyl-2-methoxytropone4withbis(mer…     

多羧基小分子化合物诱导阳离子囊泡聚集的研究

研究了由阳离子型肽脂质溴化N,N-二-十六烷基-Na-6-三甲胺基己酰基-L-丙氨酰胺(N+C5Ala2C16)形成的阳离子囊泡,在加入含羧基小分子化合物后形成的聚集。考察了乙二胺四乙酸(EDTA)加入到囊泡中后吸光值随时间的变化。结果表明:当EDTA增加到一定浓度时可以引起由阳离子囊泡的聚集;在加入Ca2+后,阳离子囊泡聚集体得到分散;借助电子显微镜观察到了囊泡的聚集和分散。超滤后,用高效液相色谱法确定了囊泡结合的EDTA量。考察了不同pH条件下EDTA对囊泡聚集的影响,当EDTA等含多羧基小分子化合物羧基解离数为三个或以上时能够引起囊泡的聚集,而少于三个时囊泡不能发生聚集。     

四元体系LiNO3-Mg(NO3)2-NH4NO3-H2O相图预测及相关相变储能材料的研究

应用修正的BET热力学模型对Mg(NO3)2-NH4NO3-H2O三元体系和LiNO3-Mg(NO3)2-NH4NO3-H2O四元体系在273～320 K的相图进行预测,并找到一个相变温度较低的四元共晶点Mg(NO3)2.6H2O-LiNO3.3H2O-NH4NO3,其质量百分数组成为:25.5%的硝酸铵,28.4%的硝酸锂,13.8%的硝酸镁和32.3%的水,通过实验对共晶点组成材料的吸放热行为进行测定,发现其熔化温度为286.3 K,且DSC测试其相变热焓为192.7 J.g-1,表明该材料可用作潜在的低温相变储能材料。     

基于纳米金与纳米银簇间表面等离子增强能量转移效应特异性检测microRNA

microRNAs(miRNAs)的灵敏检测对临床诊断具有十分重要的意义.本研究采用偶联DNA聚合酶和核酸内切酶介导的恒温扩增反应实现靶标循环再生的策略,利用纳米金(AuNPs)与纳米银簇(AgNCs)间表面等离子增强能量转移效应,开发了一种miRNA定量检测方法.在AuNPs表面组装两种探针(Probe a和Probe b)制备响应元件Probe b-Probe a-AuNP,其中Probe a通过3′端巯基共价偶联到AuNPs表面,此外具有靶标miRNA互补序列、核酸内切酶酶切序列和Probe b互补序列,Probe b为荧光AgNCs合成模板.靶标miRNA存在时,启动酶级联恒温扩增反应,导致Probe b脱离AuNPs表面,抑制了Probe b为模板合成的AgNCs与AuNPs间表面等离子增强能量转移效应,使得反应体系荧光信号增强.本方法的检出限为2.5×10-11 mol/L,与miRNAs商业化检测试剂盒相比,避免了逆转录反应,而且操作简单,检测成本低,可应用于生物样本中miRNAs分析.     

Selective adsorption and stable solidification of radioactive cesium ions by porous silica gels loaded with insoluble ferrocyanides

Development of highly functional cesium selective adsorbents for the decontamination of high-activity-level water(HALW) from the Fukushima NPP-1 accident is very urgent. In order to selectively adsorb the radioactive cesium, three kinds of novel porous silica gels loaded with insoluble ferrocyanides(SLFC) were prepared using a successive impregnation/precipitation method. Based on the results of previous research, the SLFC composites have relatively large uptake ratio above 95%, distribution coefficients(Kd) above 103 cm3/g, and excellent adsorption kinetics even in seawater. The solidification results also indicate that zeolites have an excellent Cs immobilization characteristic, gas-trapping and self-sintering abilities, and low leachability. We chose three kinds of SLFC composites to achieve the optimization of solidification by mixing with nine kinds of additives at high temperatures(up to 1200 °C). The Cs contents in the three composites were estimated to be below 30% of the initial contents and decreased with the three stages at calcination temperatures ranging from 25 to 1200 °C. By contrast, the Cs immobilization ratio was markedly lowered by mixing with additives: of those, allophane had the best immobilization result. By increasing the additive ratio to 50 wt%, the Cs immobilization ratio became almost 100% and no volatilization of Cs was detected even after calcination at 1200 °C. This result indicates that calcination of the mixture of SLFC composites after adsorbing Cs+ ions and specific additives under appropriate ratio is effective for stable solidification.     

聚丙烯熔融接枝马来酸酐反应机理的研究

改变聚丙烯（PP）熔融接枝马来酸酐（MAH）反应中的单体和引发剂的浓度以及添加适当助剂,考察了接枝产物的接枝率和恒定剪切应力（600kPa)及温度（210℃）下的剪切粘度,验证了作先前所提出的PP熔融接枝MAH的反应机理。即：在PP熔融接枝MAH的过程中,过氧化物自由基在熔融接枝过程中直接引发MAH单体及MAH单体在聚丙烯的大分子链段发生β断裂前直接被其引发而产生的接枝反应是影响产物的接枝率和分子量的关键。在不改变单体和引发剂浓度的情况下,降低过氧化物自由基在熔融接枝过程中直接引发MAH单体反应的程度而提高聚丙烯的大分子自由基直接引发MAH单体的反应趋势,是提高接枝产物接枝率和分子量的有效途径。     

氯·氨荒酸基·二苯基锗配合物的合成

以二苯基二氯化锡和氨荒酸盐为原料,合成了13种氯．氨荒酸基．二苯基锗配合物,利用元素分析,IR和1HNMR表征了这些配合物的结构,生物活性测试结果表明,该类化合物对KB和Bel癌细胞具有较好的抑制活性。     

钴基催化剂在Fischer-Tropsch合成烃中的研究进展

F2T 合成中催化剂的选择是关键。本文对近十几年来钴基催化剂在F2T 合成烃中的催化性能进行了评述, 重点讨论了负载型钴基催化剂制备过程中载体、钴源、助剂和制备方法等因素对催化剂活性、选择性控制等方面的影响。     

Photocatalytic Characterization of TiO_2 Supported on Active Carbon

Photocatalysis on TiO2, with a promising application to the elimination of organic contaminants from air and water, has been a particularly active area1. For such application, it is important to improve the efficiency of TiO_2 photocatalysts. In the most cases, the concentration of organic contaminants in water is extremely dilute (ppm level or below) and TiO_2 itself has low adsorbabilities for them, it usually takes a long time to complete their decomposition. One of the effective ways to …