扫描隧道显微镜针尖的电化学腐蚀制备方法

本文利用电化学腐蚀方法设计并搭建了一种扫描隧道显微镜（ＳＴＭ）针尖制备的直流腐蚀电路。电路中使用了９０１３三极管和ＬＭ３１１快速比较器，使电解池切断时间低于５００ｎｓ。成功地制备了质量较高的钨针类。     

扫描隧道显微镜针尖制备及其影响因素的研究

利用电化学腐蚀方法制备了扫描隧道显微镜的针尖，同时对影响针尖和尖度的各种因素进行了实验研究，并分析其电化学原理 。     

导电原子力显微镜在介质薄膜电流图像检测中产生的假像

对导电原子力显微镜在介质层电流图像检测中存在的假像进行了研究。发现这种假像归因于导电探针针尖较大的直径,其大小与被检测样品表面的缺陷点、漏洞、沟穴大小相关。研究表明,为提高图像分辨率,避免检测过程中存在的假像,需要使用具有纳米直径针尖的超尖导电探针。     

时间与温度对纳米光纤针尖腐蚀影响的研究

为增大纳米光纤针尖的锥角(即透过率),通过实验研究了腐蚀时间与温度对光纤针尖锥角、直径及表面的影响,结果表明,光纤针尖的腐蚀是非自动截止的,针尖的锥角和直径随着腐蚀时间的增加而增大,提高温度可改善针尖表面,通过选取腐蚀时间与温度可以制作不同的纳米光纤针尖.     

湿法制备 STM 针尖过程中影响因素的分析

用电化学腐蚀法，通过快速控制电路控制微针尖的腐蚀。根据电化学的动力学原理，分析了制备过程中电压变化范围、电压切断时间、电解液浓度和钨丝浸入深度等因素对微尖质量的影响，并讨论了微尖形成机制。     

时问与温度对纳米光纤针尖腐蚀影响的研究

为增大纳米光纤针尖的锥角（即透过率）,通过实验研究了腐蚀时间与温度对光纤针尖锥角、直径及表面的影响,结果表明,光纤针尖的腐蚀是非自动截止的,针尖的锥角和直径随着腐蚀时间的增加而增大,提高温度可改善针尖表面,通过选取腐蚀时间与温度可以制作不同的纳米光纤针尖。     

可用于固定床加氢的Raney镍催化剂制备方法

以镍铝合金粉末和适当有机聚合物粘结剂为原料，制备出可用于固定床加氢的颗粒状RaneyNi催化剂。X射线衍射、热重-热差和原子吸收光谱分析结果表明，在成型合金颗粒焙烧过程中，合金中的NiAl3相逐渐转化为Ni2Al3相。同时，有一小部分金属铝逐渐氧化生成α—Al2O3，可以提高催化剂的机械强度，并能抑制金属镍的氧化。催化剂活性的高压微反评价结果显示，固定床Raney镍催化剂的2-辛酮加氢催化活性高于负载型镍催化剂。     

氨基硅烷自组装分子膜的制备与摩擦特性

采用原子力显微镜对3-氨基丙基-三乙氧基硅烷自组装分子膜成膜过程进行了表征,其成膜过程包括两个阶段,第一阶段为APS水解产物与基体表面发生聚合反应,表现为"岛"式结构数量增多.第二阶段为APS分子之间发生聚合反应,表现为"岛"式结构长大.在微摩擦磨损试验机对氨基硅烷摩擦特性的研究表明,在载荷为50 mN时,钢球与APS自组装分子膜间的摩擦系数随滑动速度的增加而减小.在滑动速度为0.33×10-4 m/s时,钢球与APS自组装分子膜间的摩擦系数随着载荷的增大逐渐减小,但变化幅度不大.     

Aligning DNA on Si surface and cutting off by tips of atomic force microscope

DNA is a kind of promising molecule as nano-lead to build or connect nano-devices due to its stable linear structure and certain conductivity. Many methods have been applied to constructing nano-patterns by using DNA molecule. In this report it is presented that λ-DNA was aligned on Si substrate by using the free-flowing method and then imaged by an atomic force microscope (AFM). After the second liquid flow, a catenary-like pattern and a crossed network of λ-DNA were formed. In addition, the aligned λ-DNA was successfully cut off by tips of AFM.     

Dynamic evolution of adhesion force between protein films studied by atomic force microscope

The approaching of two hydrophobic surfaces in water will lead to the combination of air bubbles adsorbed on the surfaces, thus additional long-range attraction is induced due to the bridging capillary force. Theoretical analysis shows that the process is a first-order phase transition, while no direct experiment supports the predication. The interaction between protein modified tip of atomic force microscope and protein film on mica was studied. The results demonstrate that the adhesion force between them increases to a stable value during the calibration process and the evolution clearly indicates the character of first-order transition.     

Investigation of stress corrosion-enhanced plastic deformation using atomic force microscope

Atomic force microscope (AFM) was used to study in situ the change in slip bands during stress corrosion of brass in the ammonia solution prior to initiation of stress corrosion crack. The result showed that additive slip bands appeared ahead of a loaded notch tip during stress corrosion prior to initiation of stress corrosion crack after the constant deflection specimen was precrept for 48 h and then polished. The average height and spacing of slip bands generated during stress corrosion were about three times less or larger, respectively, than those during loading in air.     

用磁场能量计算磁力

本文介绍了用磁场能量计算磁力的方法，并利用这方法证明了两个载流闭合回路之间的磁力遵从牛顿第三定律。     

Calculation of the intracellular elastic modulus based on an atomic force microscope micro-cutting system

Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of the intracellular elastic modulus based on the contact pressure between the silicon tip of an atomic force microscope and the target cells,and cutting depth.Ovarian cells(UACC-1598) and colon cancer cells(NCI-H716) were cut into sequential layers using an atomic force microscope silicon tip.The cutting area on the cells was 8μm×8μm,and the loading force acting on the cells was increased from 17.523 to 32.126μN.The elastic modulus distribution was measured after each cutting process.There were significant differences in contact pressure and cutting depth between different cells under the same loading force,which could be attributed to differences in their intrinsic structures and mechanical properties.The differences between the average elastic modulus and surface elastic modulus for UACC-1598 and NCI-H716 cells were 0.288±0.08 kPa and 0.376±0.16 kPa,respectively.These results demonstrate that this micro-cutting method can be used to measure intracellular mechanical properties,which could in turn provide a more accurate experimental basis for the development of novel methods for the diagnosis and treatment of various diseases.     

红枣多糖微结构的原子力显微镜观测

应用原子力显微镜，对红枣多糖的微观形貌进行了观测研究，给出最佳观察方法．发现其单个分子链及其多个侧枝、聚合物链分子间互相缠绕，链间通过糖单元间不同的连接方式衍生出许多聚集体，大小在150-300nm范围内，从而直接证实了多糖大分子具有高度分枝的化学结构．同时发现红枣多糖两股糖链呈螺旋型紧密排列、多个糖链缠绕成股的情况，提示多糖在结构上可能存在类似蛋白质的自组装现象．     

用AFM对质粒DNA在云母表面的自组装研究

通过原子力显微镜(AFM)对在云母表面上自然挥干的不同质量浓度的质粒DNA分子进行扫描,原子力显微镜图像显示：当质量浓度为0．1μg／mL时,DNA分子呈现出线性结构,随着质量浓度加大至1μg／mL,DNA分子相互缠绕为网状结构,质量浓度为10μg/mL时,呈现出具有典型的聚合形态,当质量浓度进一步加大到100μg／mL,则呈现出明显的树状脉络结构．通过原子力显微镜对质粒DNA分子的形态表征,可以看出质粒DNA分子具有典型的自组装的特性．     

Imaging bacteriorhodopsinlike molecules of claretmembranes from Tibet halobacteria xz515 by atomic force microscope

HalobacteriaH.sp.xz 515 was isolated from a salt lake in Tibet. Although proton release-and-uptake across claret membrane is in reverse order compared to bacteriorhodopsin in purple membrane fromHalobacterium Salinarum, and its efficiency of proton pump is much lower, AFM image shows that the molecules are still arranged in a two-dimensional hexagonal lattice of trimers. Primary structure of Cto G-helix of the archaerhodopsin shows that it has only 56% homology with bacteriorhodopsin. But the interactive amino acid residues at the interface between B and D-helixes are conserved. These amino acid residues are believed to play a significant role in the stability of protein oligomers.     

Imaging surface structure of purple membrane partly dissolved by CHAPS with atomic force microscope

Atomic force microscope was employed to study the surface structure of purple membrane (PM) using contact mode in liquid. The surface structures of native PM and PM partly dissolved by detergent CHAPS were com- pared. Results show that 6 mmol/L CHAPS could induce some cracks and holes in PM. While Bateriorhodopsin (BR) was still presented as trimers in the two-dimensional hex- agonal structure. We assume that it was caused by the inter- action between CHAPS micellar and PM. Both absorption spectra and flash photolysis kinetic spectra indicated that BR抯 biochemical functions have been changed.