聚苯胺纳米管/壳聚糖修饰玻碳电极循环伏安法测定阿米卡星

将1.0g·L~(-1)聚苯胺纳米管-N,N-二甲基甲酰胺(DMF)溶液和1.0g·L~(-1)壳聚糖乙酸溶液以1比50的比例混合,并超声处理1h后滴涂在玻碳电极表面,制得聚苯胺纳米管/壳聚糖修饰电极(记为PANT′s/CTS/GCE)。采用循环伏安法研究了阿米卡星在聚苯胺纳米管/壳聚糖修饰电极上的电化学行为。试验结果表明:在pH5.0磷酸盐缓冲溶液中,阿米卡星在聚苯胺纳米管/壳聚糖修饰电极于-0.2V处出现一个不可逆的还原峰,且还原峰电流与阿米卡星的质量浓度在10.0～80.0mg·L~(-1)范围内呈线性关系,检出限(3S/N)为8.0mg·L~(-1)。应用此法测定注射液中阿米卡星的含量,测定结果与分光光度法测定值相一致。     

异山梨醇型聚碳酸酯与ABS树脂共混体系的结构与性能研究

采用异山梨醇型聚碳酸酯(DB),与掺混型ABS熔融共混制备了具有不同聚丁二烯(PB)含量和丙烯腈(AN)含量的DB/掺混型ABS合金,并在考察掺混型ABS特征对合金结构与性能的影响的基础上,分别使用同种掺混型ABS以及各种商品化ABS树脂,比较了DB/ABS合金和双酚A型聚碳酸酯/ABS合金的性能及其变化规律.结果表明,对DB/掺混型ABS(70/30)合金而言,PB含量变化对于合金拉伸性能的影响明显大于AN含量变化所带来的影响,在PB含量为6.3 wt%条件下,各不同AN含量的合金体系均有最好的性能表现.PB含量和AN含量变化对合金分散相形态的影响与力学拉伸性能变化特征一致.DB/ABS合金体系均具有良好的热稳定性与热力学相容性,受AN含量和PB含量变化的影响较小,合金玻璃化转变温度与DB非常接近.以双酚A型聚碳酸酯为基础的聚碳酸酯(PC)/ABS合金及以异山梨醇型聚碳酸酯为基础的DB/ABS合金,在拉伸性能变化上均表现出完全相同的规律,且无论是采用掺混型ABS还是采用商品化ABS的体系,PC/ABS与DB/ABS合金在拉伸性能所反映出的规律也是基本一致的.     

Effects of electrically inert fillers on the properties of poly(<Emphasis Type="Italic">m</Emphasis>-xylene adipamide)/multiwalled carbon nanotube composites

The effects of three types of electrically-inert fillers, calcium carbonate (CaCO₃), talc and glass fiber (GF), on electrical resistivity, crystallization behavior and dynamic mechanical properties of poly(m-xylene adipamide) (MXD6)/multiwalled carbon nanotube (MWCNT) composites are investigated. The electrical resistivity of MXD6/MWCNT composites is significantly reduced with the addition of inert fillers due to the volume-exclusion effect that leads to increased effective concentration of MWCNTs in MXD6 matrix and also due to improved MWCNT dispersion. The crystallization temperature of MXD6 increases with the addition of MWCNTs, indicating that MWCNTs can act as nucleating agent and induce crystallization of MXD6. The incorporation of inert fillers has no further effect on crystallization behavior of MXD6, but significantly improves the storage modulus of MXD6/MWCNT composite, demonstrating that CaCO₃, talc and GF filled MXD6/MWCNT composites are very promising materials with not only improved electrical property but also excellent mechanical properties.     

ELECTRICAL RESISTIVITY, CRYSTALLIZATION AND MECHENICAL PROPERTIES OF POLYPROPYLENE/MULTI-WALLED CARBON NANOTUBE/CALCIUM CARBONATE COMPOSITES PREPARED BY MELT MIXING

 Polypropylene (PP)/multi-walled carbon nanotube (MWCNT)/calcium carbonate (CaCO₃) composites are prepared by melt mixing using two types of CaCO₃ of different sizes. The electrical resistivities of the composites with the two types of CaCO₃ are all lower than those of the corresponding PP/MWCNT composites at various MWCNT loadings (1 wt%-5 wt%). The morphology of the composites is investigated by field emission scanning electron microscopy (FESEM). The crystallization behavior of PP in the composites is characterized by differential scanning calorimetry (DSC). The storage modulus, as measured by dynamic mechanical analysis (DMA), increases significantly by the presence of CaCO₃.     

Effects of Zinc oxide nanoparticles on the morphology and viscoelastic properties of polyamide 6/poly(butylene terephthalate) blends

The morphology of polyamide 6/poly(butylene terephthalate)(PA6/PBT, 70/30, W/W) blends filled with pristine Zinc oxide(ZnO) nanoparticles and ZnO surface-modified by γ-glycidoxypropyltrimethoxysilane(K-ZnO) was investigated. The incorporation of ZnO and K-ZnO by one-step compounding both resulted in a smaller size and narrower distribution of PBT domains and the effect of ZnO was greater than K-ZnO. To reveal the underlying mechanism, two-step compounding in which ZnO or K-ZnO was premixed with PA6 or PBT was conducted and the finest morphology was achieved when mixing PA6 with premixed PBT/ZnO. Transmission electron microscopy(TEM) demonstrated that ZnO was distributed in PBT in all cases and K-ZnO was enriched at the interface except when K-ZnO was premixed with PBT. ZnO and K-ZnO caused a deterioration in the melt rheological properties of PBT, which played a dominating role in the morphological changes. In addition, the interfacial localization of K-ZnO enhanced the dynamic rheological properties of PA6/PBT blends substantially.     

模板法制备三维多孔石墨烯及其复合材料研究进展

三维多孔石墨烯及其复合材料作为一种功能材料在能量存储、光电器件、气体分离和存储、吸附和传感器等领域得到关注.模板法由于能够精确控制孔尺寸、形貌和结构得到广泛研究.综述了利用分子筛、沸石、SiO2等硬模板,胶束、乳液、嵌段共聚物等软模板以及植物、粉末冶金、原位自牺牲等非传统模板制备三维多孔石墨烯及其复合材料的方法,并分析了各种方法的优缺点及材料性能.以期为三维多孔石墨烯及其复合材料的研究提供参考.     

口腔锥形束CT观察纳米羟基磷灰石诱导犬根尖闭合的研究

目的:口腔锥形束CT(cone beam CT,CBCT)评价纳米羟基磷灰石(hydroxyapatite,HA)诱导年轻恒牙根尖形成的效果.方法:选用2只56月龄犬的16颗恒切牙,术前拍摄CBCT片测量根尖面积,经去髓后,随机分为4组,A组为实验组,用HA糊剂充填根管;B、C组为阳性对照组,分别用氢氧化钙(calcium hydroxyde,CH)、Vitapex充填;D组为阴性对照组,用AH plus糊剂充填.术后4周通过CBCT片观察根尖形态并与数字化X线根尖片对比.利用CBCT系统软件测量根尖面积,每组数据与术前相比行配对t检验,各组根尖面积减少值行单因素方差分析(α=0.05).结果(1)CBCT显示:A、B、C组根尖矢状面呈内聚状,未完全闭合,D组根尖呈平行开放状.A、B、C、D组根尖横断面均呈颊舌径较大的椭圆形,未闭合.根尖片显示:A、B、C组根尖呈内聚闭合状,D组根尖呈平行开放状.(2)CBCT显示:A、B、C各组根尖面积测量数据术后与术前对比均有缩小(配对t检验P＜0.05),但3组间根尖面积缩小量差别不显著(方差分析(P＞0.05).D组术后与术前相比根尖无明显缩小(配对t检验P＞0.05)结论:(1)CBCT与根尖片相比,能更准确反映根尖形态,适于根尖诱导术后评价.(2)HA能诱导根尖闭合,影像学观察其短期效果与CH、Vitapex差别不显著.     

钙黄绿素对Yb(Ⅲ)近红外发光的敏化作用研究

近红外发光可用于荧光免疫分析、激光系统及光信号放大等方面,三价镧系离子配合物的近红外发光的研究引起了人们的兴趣。近红外发光稀土离子的发射能级低,特别容易受到溶剂分子的碰撞而产生荧光猝灭作用,通过优化配体的结构,提高配体对中心稀土离子的配位作用,尽     

导电型高分子/碳纳米管复合材料研究

介绍了作者课题组近年来在导电型高分子/碳纳米管(CNT)复合材料研究中若干有代表性的工作,我们从设计多相多组分体系角度出发,通过向单一高分子/CNT体系中添加包括无机粉体、有机高分子和第二种导电介质等第三组分来调控CNT在体系中的分布状态,以期建立提高复合材料的导电性能的技术方法,并研究了添加第三组分引致材料导电性能提...     

光纤光栅多参数桥梁结构监测系统的研究

从土木工程应用的实际情况出发,利用光纤光栅传感器具有波长绝对编码和易于复用的特点,提出工程化同时测量温度、应变和压力的全光栅型低成本分布式传感方案。设计了基于连续波调频技术的光纤光栅多参量桥梁结构监测系统,将光频域反射复用与波分复用技术相结合,实现分布式光栅传感网络的寻址,提高了系统复用容量。实验表明：所设计的传感系统能够准确监测结构重要部位的内部应变及车流量等参数,为桥梁结构的静、动载测试提供了准确的数据,同时也为桥梁的工作状态评估和健康诊断提供了依据。