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扫描电子显微镜与扫描隧道显微镜联用装置 总被引:2,自引:0,他引:2
在KYKY-1000B型扫描电子显微镜上所开发的与其联用的袖珍型扫描隧道显微镜主要有四个部分:(1)减震阻尼装置,(2)隧道探针,(3)探针扫描与逼近装置,(4)电子控制与图象采集系统。它的分辨率约为1nm,并用它观察了半导体光栅与硅上金膜的细微结构。 相似文献
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Moir patterns on HOPG were studied with scanning tunneling microscopy (STM). The results reveal that the observed Moiré patterms originate from the defects locating several layers below the surface ,which presents the first experimental evidence supporting the prediction that in HOPG the nanoscale electronic waves can propagate through several layers without obvious decay. 相似文献
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用原子力显微镜检测了不同浓度下皂苷和皂苷元的分子聚集相行为.实验表明,当浓度为1.0×10-5 mol/L时,皂苷形成分散较均匀的小片段结构,表现为皂苷分子的聚集体结构;而皂苷元由多个分子连接形成聚集体结构,与皂苷相比高度起伏较低,链的长度较长.浓度为1.0×10-4 mol/L时,皂苷出现了不规则片层与小片段共存结构;皂苷元却形成多孔的网状结构.当浓度增大到1.0×10-3 mol/L时,皂苷小分子紧密聚集、分布在云母表面;皂苷元则形成紧密聚集的大片层多孔结构.结构分析表明,分子官能团的属性对于皂苷和皂苷元分子形成的不同结构起到了关键作用,分子骨架中的糖链阻碍皂苷形成大片层结构,而皂苷元由于分子骨架中羟基间氢键相连接,易于形成大的片层结构. 相似文献
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本文首次以LB技术将四苯基卟啉铜(CuTPP)分子沉积到高定向热解石墨上,并用STM研究其表面形貌,得到了原子级分辨的CuTPP分子的表面形貌图,结果表明,CuTPP分子具有近似圆状平面结构,分子直径为1.0nm,与理论结果十分吻合,结合STM原理,讨论了有机大分子STM成像的条件。 相似文献
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NMR technologies such as relaxation, self-diffusion coefficient and other NMR methods were reviewed. The results of NMR measurements, especially, on 1H, 13C, 19F-NMR spectra and quadrupolar echo of 2H-NMR spectra on self-assembled properties and structures have been obtained. The investigations on the self-assembly of amphiphiles and the transition of self assembled structures were introduced and the determination of NMR measurements on micelles, vesicles and microemulsions was summed. 相似文献
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Rui GUO Jialin ZHANG Songtao ZHAO Xiaojiang YU Shu ZHONG Shuo SUN Zhenyu LI Wei CHEN 《物理化学学报》2017,33(3):627-632
Corannulene (COR) is considered a promising molecular building block for organic electronics owing to its intriguing geometrical and electronic properties. Intensive research efforts have been devoted to understanding the assembly behavior and electronic structure of COR and its derivatives on various metal surfaces via low-temperature scanning tunneling microscopy (LT-STM). Here we report the formation of binary molecular networks of copper hexadecafluorophthalocyanine (F16CuPc)-COR self-assembled on the highly oriented pyrolytic graphite (HOPG) and Ag (111) substrates. Intermolecular hydrogen bonding between F16CuPc and COR facilitates the formation of binary molecular networks on HOPG and further induces a preference for bowl-down configured COR molecules. This observed configuration preference disappears on Ag (111) substrate, where COR molecules lie on the substrate with their bowl openings pointing up and down randomly. We propose that strong interfacial interactions between the molecule and Ag (111) surface constrain the bowl inversion of the COR molecule, which thus retains its initial configuration upon adsorption. 相似文献
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《化学物理学报(中文版)》2007,20(4):468-474
Scanning tunneling microscopy (STM) can provide us the special means to characterize the locally physical and chemical properties of individual molecules, and even help us to manipulate the individual molecules for constructing new molecule-scale devices. Here we have adopted two new types of STM techniques to characterize the encapsulated metal atom inside a fullerene cage, and to construct a molecule-device with strong Kondo effect, respectively. The spatially dI/dV mapping spectra were used to unveil the energy-resolved metal-cage hybrid states of individual Dy@C82 molecule, and the important information about the spatial position of Dy atom inside the cage and the Dy-cage interaction was revealed. The high-voltage pulse by STM tip is controlled to induce the dehydrogenation of Co phthalocyanine molecule and change its adsorption configuration on Au(111) surface, so as to recover Kondo effect that disappears in the case of intact adsorbed molecule. 相似文献
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Direct Observation of Transition Metal Dichalcogenides in Liquid with Scanning Tunneling Microscopy 下载免费PDF全文
Ze Wang Ji-hao Wang Wei-feng Ge Wen-jie Meng Jing Zhang Qi-yuan Feng Yu-bin Hou Qing-you Lu 《化学物理学报(中文版)》2018,31(6):767-771
We present atomic-resolution images of TiSe\begin{document}$_2$\end{document} , MoTe\begin{document}$_2$\end{document} and TaS\begin{document}$_2$\end{document} single crystals in liquid condition using our home-built scanning tunneling microscopy (STM). By facilely cleaving of single crystals in liquid, we were able to keep the fresh surface not oxidized within a few hours. Using the high-stable home-built STM, we have obtained atomic resolution images of TiSe\begin{document}$_2$\end{document} accompanied with the single atom defects as well as the triangle defects in solution for the first time. Besides, the superstructure of MoTe\begin{document}$_2$\end{document} and hexagonal charge-density wave domain structure in nearly commensurate phase of TaS\begin{document}$_2$\end{document} were also obtained at room temperature (295 K). Our results provide a more efficient method in investigating the lively surface of transition metal dichalcogenides. Besides, the high stable liquid-phase STM will support the further investigations in liquid-phase catalysis or electrochemistry. 相似文献
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Matthias Bhringer Karina Morgenstern Wolf-Dieter Schneider Richard Berndt 《Angewandte Chemie (International ed. in English)》1999,38(6):821-823
Adsorption of sub-monolayer amounts of 1-nitronaphthalene (NN) onto Au(111) leads to the aggregation of NN decamers, which exhibit two-dimensional chirality and represent a racemic mixture. In analogy to Pasteur's experiment of 1848 a scanning tunneling microscope can be used to discriminate and separate the enantiomers on a molecular scale. 相似文献
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Identification of Core Segment of Amyloidal Peptide Mediated by Chaperone Molecules by using Scanning Tunneling Microscopy 下载免费PDF全文
We illustrate in this work that pristine assemblies of amyloidal peptides can be obtained by perturbations of reduced scanning bias, and show a broad distribution in peptide length. In contrast, the chaperone‐mediated peptide co‐assembly presents ordered lamellar structures with a homogeneous distribution in length, which could be attributed to the core segment of the peptide. The efforts are beneficial for gaining insight into the aggregation propensity of peptides and inter‐peptide interactions. 相似文献
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Yongfang Zheng Meng Xu Lanlan Yu Fuyang Qu Yuchen Lin Jing Xu Yimin Zou Prof. Yanlian Yang Prof. Chen Wang 《Chemphyschem》2019,20(1):103-107
The abnormal accumulation of beta-amyloids (Aβ) in brain is considered as a key initiating cause for Alzheimer's disease (AD) due to their richness in plaques and self-aggregate propensity. In recent studies, N-terminally extended Aβ peptides (NTE-Aβ) with the N-terminus originating prior to the canonical β-secretase cleavage site were found in humans and suggested to have possible relevance to AD. However, the effects of the extended N-terminus on the amyloidegenic structure and aggregation propensity have not been fully elucidated. Herein, we characterized the assembly structures of Aβ1-42, Aβ(−5)-42, Aβ(−10)–42 and Aβ(−15)-42 with both normal and reversed sequences on highly oriented pyrolytic graphite (HOPG) surfaces with scanning tunneling microscopy (STM). The molecularly resolved surface-mediated peptide assemblies enable identification of amyloidegenic fragments. The observations reveal that the assembly propensity of the C-terminal strand of Aβ1-42 is highly conserved and insensitive to N-terminal extensions. In contrast, different assembly structures of the N-terminal strand of Aβ variants can be observed with possible assignment of varied amyloidegenic fragments in the extended N-termini, which may contribute to the varied aggregation propensities of Aβ42 species. 相似文献
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Impact of Surface Dipole on Resonant Electron Injection in Scanning Tunneling Spectroscopy 下载免费PDF全文
Resonant electron injection and first-principles calculations are utilized to study single-adsorbed selenium (Se) atom on a Si(111)-7×7 surface. Theoretical calculations indicate that a negative dipole of 0.61 eV forms toward the adsorbed Se atom due to electron trans-fer from the associated Si atoms. The formation of surface dipole modifies the effective tunneling barrier height and causes a shift in the energy of the resonant state formed in the vacuum gap between the tip and the sample surface. The experimental data imply that an outward negative surface dipole of 0.61 eV causes a resonant electron injection bias shift to high voltage of about 0.45 V. 相似文献