Effect of silica nanoparticles with different sizes on the catalytic activity of glucose oxidase

In this work we present a strategy for the covalent immobilization of periodate oxidized glucose oxidase () to aminated silica nanoparticles (ASNPs) modified on gold electrodes. Silica nanoparticles greatly enhanced the catalytic ability of GOx toward the oxidation of glucose and improved the electron transfer between the GOx and the electrode surface. ASNPs of varying size—that is 100, 80, 60, and 30 nm—were prepared, and they were used to fabricate biosensors. Electrochemical impedance spectroscopy (EIS) of ferrocyanide followed the assembly process and verified the successful immobilization of on ASNPs modified on gold electrodes. From the analysis of catalytic signals of biosensors using different sizes of ASNPs under the same conditions, the surface concentration of electrically wired enzyme (Γ _ET) was estimated and was found to increase with decreasing ASNPs size. Therefore, the sensitivity of biosensors using smaller ASNPs was higher than that using larger particles. Specifically, we utilized the ASNPs with optimal size (30 nm) to fabricate the glucose biosensor. The resulting electrodes showed a wide linear response to glucose at least to 6 mM and reached 95% of the steady-state current in less than 4 s with a sensitivity of 5.02 μA mM⁻¹ cm⁻² and a detection limit of 0.01 mM. The biosensor also showed excellent stability and good reproducibility. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

肿瘤细胞中长春新碱的高效液相色谱法测定

长春新碱（ＶＣＲ）为重要和常用抗肿瘤药物之一。肿瘤细胞耐药性是导致化疗失败的主要原因。为了筛选耐药细胞的逆转剂,建立了测定肿瘤细胞内ＶＣＲ浓度的高效液相色谱法,色谱条件为：Ｚｏｒｂａｘ－ＯＤＳ反相柱２５ｃｍ×４．６ｍｍｉ．ｄ．,流动相：０．０２ｍｏｌ／ＬＫ２ＨＰＯ４（ｐＨ６．６）∶ＣＨ３ＯＨ（２０∶８０,Ｖ／Ｖ）,流速：１．０ｍＬ／ｍｉｎ,检测波长：２６７ｎｍ。方法简单、快速、选择性好,在１０～２００ｍｇ／Ｌ范围内ＶＣＲ浓度－峰高呈良好的线性关系（ｒ＝０．９９９８）,仪器灵敏度为４ｎｇ。     

用热重分析法研究氢氧化镧的热分解过程

在研究固相交换反应过程中,我们对氢氧化镧进行了热重分析,发现氢氧化镧的热分解过程是分两步进行的,由其热重曲线计算了氢氧化镧热分解反应的活化能和反应级数。     

Pt-Sn/MgAl2O4催化剂的TPR和H2-TPD研究

Pt Sn/MgAl 2O 4 catalysts prepared by co impregnation with nominal 0 35% platinum and varying content of tin (0～2 5%) were characterized by temperature programmed reduction (TPR) and temperature programmed desorption of hydrogen (H 2 TPD). TPR results showed that platinum catalyzed the reduction of tin. However, the average oxidation state of tin after reduction depended upon the concentration of tin on the catalysts. H 2 TPD data indicated that tin addition inhibited the inactivated adsorption of hydrogen but promoted the activated adsorption, implying that tin modified both the ensembles of platinum and metal support interface, thus increasing hydrogen mobility and promoting hydrogen spillover.     

Ni80P20合金的非晶化度与催化活性的关联

采用淬冷法,通过改变冷却铜辊的转速,得到了一系列具有不同非晶化度的Ｎｉ８０Ｐ２０合金材料。以乙炔加氢为探针反应的催化研究结果表明,合金的催化活性随非晶化程度的增加而增加,同时,非晶态合金具有比相应的晶态金合明显优良的催化稳定性,ＸＲＤ和ＡＥＳ深度分析显示：在氧化－还原活化处理过程中,相对晶态合金而言,非晶态合金显示明显的“惰性”,活化后的表面上含有较多的对加氢反应有促进作用的氧化镍相互作用的结构。     

水蒸汽对PtSn／Al2O3催化剂结构及反应性能的影响

比较研究了Ａｌ２Ｏ３负载的铂及ＰｔＳｎ催化剂在氮气及水蒸汽稀释条件下的丙烷脱氢性能,并利用ＸＰＳ及氢脉冲吸附对催化剂进行了表征。结果表明,水蒸汽可促使Ｐｔ／Ａｌ２Ｏ３催化剂的铂晶粒烧结。与在氮气氛中相比,在水蒸汽存在下反应显著提高了Ｐｔ／Ａｌ２Ｏ３的丙烷转化率,却降低了丙烯的选择性。另一方面,水蒸汽可调变ＰｔＳｎ／Ａｌ２Ｏ３催化剂的结构,破坏了ＰｔＳｎ／Ａｌ２Ｏ３中与锡相互作用的铂簇团结构。从而导     

类锂等电子系列(1s2p2p)~4 P~e和(1s2s2p)~4 P~0态的能量和精细结构研究

利用改进的马鞍点方法,截断变分方法,并考虑能量的相对论修正和质量极化效应,计算和研究了类理等电子系列的两个四重态（１ｓ２ｐ２ｐ）４Ｐ０和（１ｓ２ｓ２ｐ）４Ｐｅ态的精细结构和平均跃迁波长,并与实验和其它理论计算结果进行了比较。     

纤维/金属网增强层板低速冲击损伤机理和演化

本文首先通过落锤低速冲击实验测试了纯玻璃纤维增强环氧树脂复合材料和304不锈钢丝网(SSWM)/玻璃纤维混杂复合材料的力学性能,探究了SSWM嵌入数量对混杂复合材料抗冲击性能的影响．随后采用Abaqus有限元软件建立了混杂复合材料的低速冲击模型,分别采用三维Hashin失效准则和Jason-Cook破坏准则模拟了纤维/基体和SSWM的损伤;建立了基于表面接触的内聚力模型来模拟界面分层;编写了VUMAT用户子程序定义混杂复合材料层合板的渐进失效过程．结果表明：相较于纯玻璃纤维增强环氧树脂层合板,SSWM/玻璃纤维混杂增强环氧树脂层合板的抗冲击性能更优,其中铺层形式为铺层III的混杂复合材料抗冲击性能最佳．通过对比发现有限元仿真结果与实验结果吻合良好,表明建立的模型适用于SSWM/玻璃纤维混杂增强环氧树脂复合材料低速冲击损伤的评估．通过分析仿真结果发现混杂复合材料的低速冲击损伤主要是冲击区域的纤维断裂、基体破坏和层间分层;SSWM通过吸收和传递冲击能量从而提升了混杂复合材料的抗冲击性能．