Friction behavior of monolayer molybdenum diselenide nanosheet under normal electric field

The friction behavior of monolayer molybdenum diselenide (MoSe₂) under normal electric field was studied by the atomic force microscope. The friction coefficients of MoSe₂ are increasing with bias voltage applied on the Si substrate. The results show that the adhesion and electrostatic forces increase with bias and approximately follow a parabolic law. The friction force and surface potential are of the same tendency with bias application time, and the contribution of charges accumulation to friction is considerable. The mechanisms of the friction behavior under external normal electric field were explained with electrostatic force and adsorption. This study reveals a possibility of electronically controlling friction in two-dimensional MoSe₂ system, with potential applications in solid lubricant and moving parts for MEMS devices.     

隧道电子激发的辛硫醇条纹相自组装膜上卟啉单分子荧光

利用扫描隧道显微镜诱导发光技术,对单个卟啉分子的电致荧光现象进行了研究. 为了避免金属衬底对单个卟啉分子的荧光淬灭,利用条纹状辛硫醇自组装膜作为脱耦合层,实现了单个中性卟啉分子的电致荧光,并且发现分子荧光的产生呈现双极性特征. 另外,分子瓣上的荧光强度要强于分子中心的荧光强度.     

近场显微干涉成像中的探测角度和偏振问题研究

用偶极子耦合系统来模拟近场干涉测量中的探针样品关系,并利用各电场分量之间的组合方程组精确计算出其可能探测到的强度和相位像。结果显示,近场干涉所测量到的近场像的分辨力和探测器的方位及参考光的偏振方向之间有较强的依赖关系,随着探测器位置不同或者参考光偏振方向的变化,同一样品在同一照明条件下所得到的图像也会发生明显的改变。在倏逝波照明的情况下,近场像的精确度随着探测器相对于样品视角的增大而改善,且在不同偏振方向的近场像中,只有偏振方向垂直于样品表面的像能真实反映样品的细节分布,且同时具有足够的强度分布。     

基于图像清晰度评价函数的显微镜自动调焦技术研究

自动调焦技术是提高自动显微镜测量精度的一个重要手段,图像清晰度评价函数是计算机自动调焦中的关键技术。根据图像清晰度评价函数实现了显微镜的自动调焦。     

染色体的显微光谱

利用显微光谱技术在可见光范围内测定了蚕豆根尖染色体，小白鼠髓细胞染色体和小白鼠骨髓细胞微核的光谱，其光谱形状各具有特征，峰值亦有差异。     

In Vitro Monitoring of Live Cardiomyocytes Dynamics by a Scanning Near Field Optical Microscope Setup

We describe an original scanning near field optical microscope setup developed to examine rhythmically beating cardiac myocytes fully immersed in culture media. Scans could be halted at any point to record localized contraction profiles. Contractions could be detected with high sub nanometric vertical sensitivity and changed shape dramatically within adjacent sub micron-sized areas. We believe that the spatial dependency of contractions arises because of system’s ability to resolve the dynamic behavior of individual sub membrane actin bundles. Our results, combining imaging and real time recording in localized areas, reveal a new, non-invasive method for studying sub micron morphological activity in live biological samples.This paper was originally presented at the 5th International Conference on NEAR FIELD OPTICS and RELATED TECHNLOGIES (NFO-5), which was held on December 6–10, 1998 at Coganoi Bay Hotel, Shirahama, Japan, in cooperation with the Japan Society of Applied Physics and Mombusho Grant-in Aid for Scientific Research on Priority Areas “Near-Field Nano-optics” Projects, sponsored by Japan Society for the Promotion of Science.     

含银偏振玻璃的制备及光学性能

研究了拉伸还原法制备含银Ｒ２Ｏ－Ｂ２Ｏ３－Ａｌ２Ｏ３－ＳｉＯ２系统偏振玻璃的工艺,得到了工艺波段在６００￣１４００ｎｍ、透光度９０％、消光比１６２：１的玻璃偏振片,着重探讨了拉伸比对偏光性能的影响,并对偏振机理作出了解释。     

Raman spectroscopy of automotive paints: Forensic analysis of variability and spectral quality

Raman spectroscopy was evaluated as a forensic technique for the analysis of automotive paints with the purpose to verify the measurement variability as well as to study the spectral quality by means of parameters and conditions. The objective lens, accumulation number, and laser (power, mode, and wavelength) were observed to significantly affect the spectral quality and thus should be taken into consideration during the development of a forensic database. On the other hand, exposure time, Raman shift range, and baseline correction had less influence on the features of the obtained spectra. Interestingly, samples collected from the bumper coating composed of a plastic substrate in comparison with fragments obtained from other parts of the same vehicle containing metallic substrate showed different absorption band patterns. In addition, less variability of data acquired directly onto the paint chip’s surface has demonstrated that direct analysis should be preferred during spectra library development as opposed to cross-section measurements. Sample homogeneity and distinction power of the technique combined with Principal Components Analysis were also investigated. The preliminary results showed that although Raman spectroscopy is extremely accurate in the identification of vehicles, it is necessary to pay particular attention to the spectral variability in order to avoid false database matching and misleading of forensic investigations. Therefore, we suggest that separated spectra library shall be developed for each laser wavelength as well as for each sample substrate. Further studies with a higher number of paint chips will enable the establishment of prediction models aimed to identify unknown samples involved in hit-and-run cases.     

Ion‐Beam Sculpting of Nanowires

Nanomaterials often undergo unusual mechanical deformations compared to their bulk counterparts when irradiated with ion‐beams. This study visualizes and investigates some of the unusual interactions that can occur in nanomaterials during irradiation with medium‐energy ion‐beams using a helium‐ion microscope (HIM). Ion‐beam sculpting of semiconductor nanowires (NWs) with sub‐10 nm features is demonstrated. Moreover, irradiation‐induced growth of NWs at room‐temperature is discovered. The new concept and possible mechanism of irradiation‐induced VLS (vapor–liquid–solid) growth of NWs is introduced. These results are the basis for further fundamental and technological developments toward manipulation and visualization of ion–matter interactions at the nanoscale.     

Precise autofocusing microscope with rapid response

The rapid on-line or off-line automated vision inspection is a critical operation in the manufacturing fields. Accordingly, this present study designs and characterizes a novel precise optics-based autofocusing microscope with a rapid response and no reduction in the focusing accuracy. In contrast to conventional optics-based autofocusing microscopes with centroid method, the proposed microscope comprises a high-speed rotating optical diffuser in which the variation of the image centroid position is reduced and consequently the focusing response is improved. The proposed microscope is characterized and verified experimentally using a laboratory-built prototype. The experimental results show that compared to conventional optics-based autofocusing microscopes, the proposed microscope achieves a more rapid response with no reduction in the focusing accuracy. Consequently, the proposed microscope represents another solution for both existing and emerging industrial applications of automated vision inspection.