温度对PTCDA结构形貌影响的Raman和AFM分析

通过真空蒸发将PTCDA淀积在p-Si(100)面.采用Raman光谱,AFM分别研究了衬底温度对于PTCDA分子结构和表面形貌的影响,进而完善了p-Si基PTCDA薄膜的生长机制.     

无氰脉冲电镀金工艺及其在空腔靶中的应用

提出采用脉冲电镀在无氰亚硫酸盐体系中制备镀金层并应用在空腔靶上。讨论了电流密度、pH、温度及脉冲占空比对电镀过程及镀层性能的影响。结果发现,当占空比在1∶(9~18)时,镀层最细致、光滑,粗糙度在30 nm左右。采用原子力显微镜观测了该工艺处理后的空腔的形貌。由此工艺获得的金腔结构稳定,均匀致密,精度良好且外观光亮。     

双功能弯曲光纤探针的制作

探针是所有扫描探针显微镜的关键部件。本文提出了一种采用普通单模光纤制作在原子力和光子扫描隧道组合显微镜(AF/PSTM)上使用的弯曲光纤探针的方法。通过合理的选择实验参数,经过热拉伸与化学腐蚀两个过程,得到弯曲部分的角度为110°~120°、锥角约60°~80°的弯曲光纤探针。经扫描电镜观察,光纤探针的尖端直径小于100nm。此种方法加工光纤探针的成品率约70%左右。     

丙纶表面沉积纳米薄膜的原子力显微镜分析

采用低温磁控溅射技术在丙纶(熔喷法非织造布)表面沉积铝、氧化锌和聚四氟乙烯纳米薄膜,用原子力显微镜观察纤维基材及三种纳米薄膜沉积在纤维表面的微观结构,为进一步对聚合物纤维材料磁控溅射功能化加工的工艺参数优化调整,以及对沉积材料在纤维表面的结合机理的研究提供理论依据。通过对原子力显微镜图像分析发现,丙纶(熔喷法非织造布)表面比较平滑,而丙纶长丝的表面则成一定的周期性条纹状结构;低温磁控溅射技术在丙纶(熔喷法非织造布)表面构建的功能性纳米薄膜随着沉积材料的不同,其在纤维表面的聚集形态不同。铝和氧化锌在纤维表面形成纳米颗粒状结构,而高分子材料聚四氟乙烯则形成纳米条带状形貌。分析和测量了金属颗粒和聚四氟乙烯条带的尺寸。     

基于原子力显微镜的纳米三维刻划加工控制系统

介绍了一套新型的纳米三维刻划加工控制系统,系统基于AFM原子力显微镜,配合三维微动工作台,设计开发了专门的加工控制装置,成功的实现了纳米刻划加工中的深度控制问题,可实现在X、Y、Z方向分别为100μm×100μm×20μm范围内,X、Y向精度为±5 nm、Z向精度为±10 nm的三维结构机械刻划加工,应用结果表明,该系统实现了具有在位形貌检测功能的三维纳米刻划加工,在微纳米刻划加工领域具有一定的实用性和推广价值。     

Self-Assembly and Neurotoxicity of β-Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

The three GxxxG repeating motifs from the C-terminal region of β-amyloid (Aβ) peptide play a significant role in regulating the aggregation kinetics of the peptide. Mutation of these glycine residues to leucine greatly accelerates the fibrillation process but generates a varied toxicity profile. Using an array of biophysical techniques, we demonstrated the uniqueness of the composite glycine residues in these structural repeats. We used solvent relaxation NMR spectroscopy to investigate the role played by the surrounding water molecules in determining the corresponding aggregation pathway. Notably, the conformational changes induced by Gly³³ and Gly³⁷ mutations result in significantly decreased toxicity in a neuronal cell line. Our results indicate that G³³xxxG³⁷ is the primary motif responsible for Aβ neurotoxicity, hence providing a direct structure–function correlation. Targeting this motif, therefore, can be a promising strategy to prevent neuronal cell death associated with Alzheimer's and other related diseases, such as type II diabetes and Parkinson's.     

高度有序多孔阳极氧化铝膜形成机理的探讨

使用高纯铝片,利用电化学阳极氧化制备了多孔阳极氧化铝(AAO)膜,用原子力显微镜(AFM)对其形貌进行了表征,提出铝阳极氧化过程中纳米孔从无序到有序的自组织模型,探讨了高度有序六角形纳米孔阵列的形成过程,并分析了影响纳米孔有序度的因素及提高有序度的途径.根据自组织模型探讨了长时间阳极氧化和二次氧化条件下形成高度有序六角形纳米孔阵列的机理.     

Effects of scratching directions on AFM-based abrasive abrasion process

AFM-based single abrasive abrasion process is widely employed in the surface micro/nanomachining for fabrication of structures at the nanometer scale. The wear depth and roughness are significantly important in the application of these structures. To study effects of scratching directions on the wear depth and roughness within the wear mark, single groove scratching test and wear test on the surface of polished single crystal silicon were carried out using AFM with a pyramidal diamond tip. Single groove scratching tests indicated that tip geometry leads to different removal states such as cutting and plowing. At the same load, deeper wear depth and rougher surface were produced by using the scratching direction perpendicular to the long axis of the cantilever rather than parallel to the long axis of the cantilever. Surface roughness decreases with respect to the feed scratching perpendicular to the long axis of the cantilever, whereas while scratching along the long axis of the cantilever, the surface roughness is rougher at the small feed. This is attributed to the different stiffness of the cantilever along different scratching directions and different removal states between the tip and sample.     

Morphology of wax modified coil coatings without and with pigmentation

Wax modified coil coatings without and with white pigmentation were analyzed by optical light microscopy, Raman spectroscopy and Atomic Force Microscopy. By optical light and Raman microscopy dispersed spherical wax domains in the micrometer range were ascertained on the surface and within the bulk of the coatings. By the combined Atomic Force microscopical and Raman spectroscopical approach it was possible to detect resin and pigment residues in the lubricant features with diameters above 2 μm. Vice versa indications for wax inclusions with diameters below 2 μm in the matrix and rather thin wax layers expanding from the spherical lubricant domains onto the surface were obtained. As to the wax distribution evaluated by optical light and Raman microscopy significant differences between clearcoat and white topcoat were detected. The non-pigmented coating exhibited smaller wax features and an inhomogeneous distribution with less wax on the surface.     

Adsorption and inhibition effect of 6-benzylaminopurine on cold rolled steel in 1.0 M HCl

The adsorption and inhibition effect of 6-benzylaminopurine (BAP) on cold rolled steel (CRS) in 1.0 M HCl at 25-50 °C was studied by weight loss and potentiodynamic polarization methods. The results showed that BAP was a good inhibitor in 1.0 M HCl, and the inhibition efficiency (IE) increased with the inhibitor concentration. The adsorption of BAP on the CRS surface obeyed the Langmuir adsorption isotherm equation. Both thermodynamic parameters (adsorption heat ΔH⁰, adsorption free energy ΔG⁰ and adsorption entropy ΔS⁰) and kinetic parameters (apparent activation energy E_a and pre-exponential factor A) were calculated and discussed. Polarization curves showed that BAP acted as a mixed-type inhibitor in hydrochloric acid. Good agreement between weight loss and polarization methods was obtained. The adsorbed film on CRS surface containing optimum dose of BAP was investigated by Fourier transform infrared spectroscopy (FTIR) and atomic force microscope (AFM). Quantum chemical calculation was applied to elucidate the adsorption mode of the inhibitor molecule onto steel surface. Depending on the results, the inhibitive mechanism was proposed from the viewpoint of adsorption theory.