微机化紫外可见区现场光谱电化学联用测量系统的研制

本文报道了由微机控制的紫外可见区现场(in situ)光谱电化学联用测量系统的硬件和软件设计。该系统可以测量电化学调制反射光谱,光电流谱和光电容谱,并可实现同一实验体系的同时联合测量,这些功能均由计算机软件完成。该系统已应用于金属、半导体、半导电氧化膜电极/溶液界面行为的研究,得到了一些新的实验结果

周期性机械拉伸对表皮干细胞分化及生物学效应的影响

背景:表皮干细胞是创面愈合过程中的重要细胞成分之一,表皮干细胞分布在基底层,约占基底层细胞的1%-10%,对皮肤的张力有较高的感应能力,其细胞表面有高水平的integrin-beta1表达,因而integrin-beta1高表达被认为是KSC分子标志之一,同时也是表皮干细胞对皮肤张力的感应器。。整合素尤其是整

Reaction of p-Chloronitrobenzene Adsorbed on Silver Nanoparticles

Corresponding author. Email: [email protected]; Tel: +86-592-2189023[中文文摘]表面增强拉曼光谱(SERS)具有极高的检测灵敏度,通过检测吸附分子的SERS信号,可以获得表面吸附分子的结构以及可能发生的反应.在拉曼激发光源的辐射下,在碱性溶液中,银纳米粒子表面吸附的对氯硝基苯(PCNB)的SERS光谱与其固体的常规拉曼光谱相比,出现异常SERS谱.通过采用密度泛函理论(DFT)计算,对PCNB以及可能的偶联产物p,p′-二氯偶氮苯(DCAB)进行理论分析以及谱峰归属,发现这些异常峰来自其偶联产物DCAB的偶氮C-N=N-C基团的基频振动. [英文文摘]Surface-enhanced Raman spectroscopy (SERS) on silver nanoparticles is highly sensitive because of surface plasmon resonance. We have studied the structures and photoinduced chemical reactions of p-chloronitrobenzene (PCNB) molecules adsorbed on silver nanoparticles using a combination of SERS and density functional theory (DFT) calculations. When the PCNB molecules are adsorbed to the surface of silver nanoparticles in alkaline solution, the SERS spectra are very different from the normal Raman spectra of PCNB. Comparison of the DFT simulated Raman spectra of PCNB and p,p-dichloroazobenzene (DCAB) indicates that the new peaks in the SERS spectrum of PCNB adsorbed on silver nanoparticles arise from the azo (C－N＝N－C) group of DCAB.国家自然科学基金(20973143, 91027009, 21021002);国家重点基础研究发展规划项目(973)(2009CB930703);厦门大学(2010121020

Selectivity of biopolymer membranes using HepG2 cells

Bioartificial liver (BAL) system has emerged as an alternative treatment to bridge acute liver failure to either liver transplantation or liver regeneration. One of the main reasons that the efficacy of the current BAL systems was not convincing in clinical trials is attributed to the lack of friendly interface between the membrane and the hepatocytes in liver bioreactor, the core unit of BAL system. Here, we systematically compared the biological responses of hepatosarcoma HepG2 cells seeded on eight, commercially available biocompatible membranes made of acetyl cellulose&ndash;nitrocellulose mixed cellulose (CA&ndash;NC), acetyl cellulose (CA), nylon (JN), polypropylene (PP), nitrocellulose (NC), polyvinylidene fluoride (PVDF), polycarbonate (PC) and polytetrafluoroethylene (PTFE). Physicochemical analysis and mechanical tests indicated that CA, JN and PP membranes yield high adhesivity and reasonable compressive and/or tensile features with friendly surface topography for cell seeding. Cells prefer to adhere on CA, JN, PP or PTFE membranes with high proliferation rate in spheriod-like shape. Actin, albumin and cytokeratin 18 expressions are favorable for cells on CA or PP membrane, whereas protein filtration is consistent among all the eight membranes. These results further the understandings of cell growth, morphology and spreading, as well as protein filtration on distinct membranes in designing a liver bioreactor.</p

GaNxAs1-x(x＜0.01)中合金态的光学特性

应用多种光谱手段研究了分子束外延生长在半绝缘的(001,GaAs衬底上的低氮含量的GaNAs中三元合金态的光学特性.变温PL谱揭示了合金态的本征特性以及其与氮的杂质态的根本区别,而脉冲激发的光荧光谱则进一步显示了合金态的本征光学特性.最后还研究了GaNAs的吸收光谱特征

显微光谱研究半绝缘GaAs带边以上E_0+△_0光学性质

通过显微光致发光技术和显微拉曼(Raman)技术研究了半绝缘GaAs(SI-GaAs)晶体的带边附近的发光.在光荧光谱中,观察到在高于GaAs带边0.348 eV处有一个新的荧光峰.结合Raman谱指认此发光峰来源于GaAs的E_0+△_0能级的非平衡荧光发射.同时,通过研究E_0+△_0能级的偏振、激发光强度依赖关系,以及温度依赖关系说明E_0+△_0能级与带边E_0共享了共同的导带位置Г_6,同时这也说明在GaAs中主要是导带的性质决定了材料的光学行为.同时,通过与n-GaAs和δ掺杂GaAs相比较,半绝缘GaAs晶体的E_0+△_0能级的发光峰更能反映GaAs电子能级高临界点E_0+△_0的能量位置和物理性质.研究结果说明显微光致发光技术是研究半导体材料带边以上能级光学性质的一种非常有力的研究工具

GaNAs/GaAs中的激子局域化和发光特性

通过多种光谱手段研究了GaNAs量子阱和体材料中的局域态和非局域态的不同光学特性.在超短激光脉冲激发下,第一次在GaNAs/GaAs量子阱发光光谱中,观察到非局域激子发光.选择激发光谱表明,局域中心主要聚集在GaNAs、GaAs异质结界面.在低N含量的GaNAs体材料发光光谱中,除了与N相关的局域态发光外,也发现发光特性完全不同的GaNAs合金态发光.这些结果为理解Ⅲ-V-N族半导体的异常能带特性具有十分重要的意义