聚多巴胺功能化的四氧化三钴纳米复合材料的制备及电催化性能

通过简单的自聚合反应在四氧化三钴表面包覆聚多巴胺膜,联合使用纳米铂和辣根过氧化物酶用于电催化还原过氧化氢。结果表明,聚多巴胺的使用增强后续纳米铂的负载量和辣根过氧化物酶的生物活性;四氧化三钴、纳米铂和辣根过氧化物酶的多重信号放大作用,大大增强了该复合材料的催化活性,提高了过氧化氢传感器的灵敏度。优化实验条件下,传感器对过氧化氢的检测范围为0.1～700μmol·L^-1,检测限为0.08μmol·L^-1。     

反相离子对色谱中有机溶剂浓度和离子对试剂浓度对保留值的影响

我们测定了氨基苯磺酸和氨基萘磺酸在反相离子对色谱中不同乙腈/水, 甲醇/水配比和离子对试剂浓度下的保留值,并把两种冲洗剂下的保留值和关系式lnk'=a+C~c~b中的参数a,C作线性关联,得到很好的相关性,这表明有机溶剂乙腈和甲醇对选择性并无显著的影响,但乙腈有更大的冲洗强度.证明关系式lnk'=A+Blnc~p+C~c~ b能较好地描述有机溶剂和离子对试剂浓度对保留值的影响, 但当离子对试剂浓度较高时该关系式不成立.同时提出了有机溶剂浓度和离子对试剂浓度"等同效应" 的概念     

L-苯丙氨酸衍生物与脂肪胺构筑双组分超分子凝胶

设计合成了系列单链L-苯丙氨酸衍生物,该系列衍生物单组分没有胶凝性能. 选择脂肪胺作为配对物,与L-苯丙氨酸衍生物组成双组分体系后能够胶凝许多有机溶剂形成凝胶. 流变学测试显示该凝胶体系弹性模量（G’）比粘性模量（G"）约高一个数量级,有着很好的机械性能,并且呈现出典型的类固体的流变学行为. 傅里叶变换红外（FT-IR）光谱、核磁共振（NMR）谱、小角X射线衍射（SAXS）和扫描电镜（SEM）结果表明,凝胶中胶凝剂分子形成纤维状或片层状的聚集体,羧基（―COOH）和氨基（―NH₂）的酸碱作用、酰胺基团间（―CONH―）的氢键作用以及分子间范德华作用力是形成该凝胶的主要驱动力. 凝胶中胶凝剂分子自组装形成具有周期性的层状有序结构,层状结构进一步组装形成纤维状聚集体,最终形成三维网状结构阻碍溶剂流动形成凝胶.     

HRP-纳米金/纳米硫化镉/聚天青Ⅰ修饰玻碳电极的制备及用作过氧化氢生物传感器

以玻碳电极为基底,电聚合一层表面均匀的带正电性的聚天青Ⅰ膜,再通过静电作用吸附一层带负电性的具有大比表面积的纳米硫化镉来固定纳米金和辣根过氧化物酶(HRP)的复合物,制备出性能良好的过氧化氢生物传感器.采用循环伏安法(CV)和计时电流法对该生物传感器的性能进行了研究.试验表明:该方法不仅增加了酶的吸附量,还有效保持了酶的生物催化活性,此生物传感器对过氧化氢浓度在4.0×10-7～1.2×10-3mol·L-1范围内呈线性关系,检出限为1.4×10-7mol·L-1.     

A subspace expanding technique for global zero finding of multi-degree-of-freedom nonlinear systems

A subspace expanding technique(SET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains, which are called cells. The covering set of the cells is identified by parallel calculations with the root bracketing method. The covering set can be found first in a low-dimensional subspace, and then gradually extended to higher dimensional spaces with the introduction of more equations and variables into the calculations. The results show that the proposed SET is highlyefficient for finding zeros in high-dimensional spaces. The subdivision technique of the cell mapping method is further used to refine the covering set, and the obtained numerical results of zeros are accurate. Three examples are further carried out to verify the applicability of the proposed method, and very good results are achieved. It is believed that the proposed method will significantly enhance the ability to study the stability, bifurcation,and optimization problems in complex MDOF nonlinear dynamic systems.     

二氧化硅@聚合物同轴纳米纤维

The preparation and formation mechamsm ot silica/polyvinylpyrrolidone(PAN) coaxial nanofibers were presented in this paper. The PVP-PAN composite nanofibers were obtained via an electrospinning technique, while SiO2 nanoparticles were prepared according to a Stoeher method. The measurements of water contact angle(WCA), the compared results of silica coating PVPPAN composite nanofibers with PAN nanofibers indicate that much PVP resided on the composite nanofiber surface, which resuks in the occurrence of SiO2@polymer coaxial nanofibers due to the formation of hydrogen bonding between silica and composite nanofibers and subsequent adsorption of silica on the fiber surface.     

反相液相色谱中溶质保留与溶剂化结构参数间的定量关系

本文研究了等度条件下反相液相色谱中溶质保留与溶剂化结构参数间的定量关系;考察了反相液相色谱保留值变化规律式lnk'=a+cC~b中参数a.c 与溶剂化结构参数间的定量关系,结果表明能较好地预测等度和不同冲洗剂组成下溶质的保留值,将乙腈-水和甲醇-水冲洗剂下的a.c值定量关联,表明在考虑溶质的氢键作用参数后,其相关性有所提高.     

钨氧键价参数的研究

根据键价理论中的指数方程s_ij=exp[(R_o-r_ij)/B],利用晶体结构报告中不同氧化态n的329个W-O键长数据,选取不同的B值对键价参数R₀进行了拟合,建立了一系列R₀-n线性方程,并进而得到与W氧化态无关的键价参数R₀=0.1896 nm和B=0.028nm.与文献数据比较,本文拟合的键价参数取得了较好的键价和计算结果,讨论了几个应用的实例.     

Metallo-Phosphorylation of Alkynes: Reaction of Alkynes with Cp2Zr(1-butene) ( PR3 ) and Chlorophosphate

Phosphorylation of alkynes is an attractive reaction for the synthesis of stereodefined alkenylphosphonates that are useful intermediates in organic synthesis. Particularly interesting and challenging reactions are those involving the region- and stereo-selective simultaneous introductions of phosphate and other functional groups to multiple carbon-carbon bonds.[1,2]     

铈锰/硅基气凝胶载体的制备及其在合成碳酸二苯酯中的应用

分别采用原位合成法、浸渍法制备不同组成的铈锰/硅基气凝胶载体,利用XRD、BET、TEM、EDS、FT-IR等手段对其结构进行表征.结果表明:采用浸渍法制备的铈锰/复合硅基气凝胶,铈锰金属氧化物为纳米尺寸颗粒,孔道保留较为完整.以苯酚催化氧化羰基化合成碳酸二苯酯反应,考察了铈锰/硅基复合气凝胶载体载钯催化剂的催化性能,结果表明以浸渍法制备组分为m(Ce+Mn)/m(SiO_2)=20%载钯催化剂,在反应压力5 MPa、反应温度75℃、反应时间6 h时,碳酸二苯酯单程收率可达21.58%,选择性为99.27%.