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Scanning tunneling microscopy (STM) at 5 K reveals that native atoms in the surface layer of a semiconductor crystal become bistable in vertical height when a nanostructure is assembled nearby. The binary switching of surface atoms, driven by the STM tip, changes their charge state. Coupling is facilitated by assembling adatom chains, allowing us to explore the emergence of complex multiple switching. Density-functional theory calculations rationalize the observations and a lattice-gas model predicts the cooperative behavior from first principles.

Quantum-dot molecules were constructed on a semiconductor surface using atom manipulation by scanning tunneling microscopy (STM) at 5 K. The molecules consist of several coupled quantum dots, each of which comprises a chain of charged adatoms that electrostatically confines intrinsic surface-state electrons. The coupling takes place across tunnel barriers created reversibly using the STM tip. These barriers have an invariant, reproducible atomic structure and can be positioned---and repeatedly repositioned---to create a series of reconfigurable quantum-dot molecules with atomic precision.

The surface structures of thin erbium silicide layers formed on Si(1 0 0) substrate by solid phase epitaxy are studied by using the in situ high energy electron diffraction, low energy electron diffraction, Auger electron spectroscopy, scanning tunneling microscopy, and ex situ grazing X-ray diffraction. Nanowires and nanoislands of Er silicide coexist on the Si substrate surface and a c(2×2) reconstruction is observed on the top of these nanostructures. The crystalline structure of the Er silicide nanostructure is found to be tetragonal ErSi2. A Si-adatom model for the c(2×2) reconstruction is proposed. The total energy calculation based on the discrete-variational self-consistent multipolar cluster method identifies that the hollow site Si adatom model might be the most energetically favorable one.

In this work, erbium silicide is grown on the Si(1 0 0) surface by depositing Er onto the substrate and annealing at 600–700 °C. Many nanowires of Er silicide are formed with lengths in the range 10–100 nm. The formation and evolution of this nanostructure are investigated at atomic scale directly with scanning tunneling microscopy and low-energy electron diffraction. The direction of these nanowires is found perpendicular to that of Si dimer rows. It is shown that Er coverage and annealing temperature have an effect on the formation of nanowires. On the surface between nanowires, new (5×2) and c(5×4) reconstructions are observed, giving an implication to understand the growth behaviors of Er silicide on Si(1 0 0) surface.

Lung cancer is a common malignant neoplasm that is prone to distant metastasis. However, the incidence of multiple cutaneous and intestinal metastases is rare. The present study describes the case of a 62-year-old female who was admitted to The Affiliated Hospital of Shandong Academy of Medical Sciences in August 2013 with multiple cutaneous lumps. Contrast-enhanced computed tomography showed nodules and masses in the right lung, and multiple enlarged lymph nodes in the mediastinum and right hilum. Biopsies of the lumps in the right lung and skin revealed moderately-differentiated adenocarcinoma, which were considered to be cutaneous metastases of lung cancer. The patient subsequently experienced symptoms of rectal irritation. A digital rectal examination and colonoscopy were performed, and the consequent pathological biopsy identified moderately-differentiated adenocarcinoma. After analyzing the results of previous pathological examinations and immunohistochemistry, it may be suggested that intestinal metastasis had developed. This case highlights the fact that a comprehensive analysis and examination should be performed for suspected cutaneous and intestinal lesions, during which, a pathological biopsy is of great importance in order to form the correct diagnosis for timely treatment.

Scanning tunneling microscopy of longitudinally polarized surface acoustic waves (SAWs) yields amplitude and phase images with nanometer resolution. The eccentricity of the surface oscillation calculated from the experimental data by the model of Chilla et al. is 88°±5° in good agreement with the macroscopic value for high velocity pseudo SAWs. Our study reveals that reliable amplitude and phase information can be deduced even from atomic scale features; however, the local surface geometry and tip shape need to be treated in more detail.

In consideration of personal wealth and public security, time is one of the most significant factors influencing the real-time web service, such as E-Commerce, aviation, military affairs, etc. However, there is no suitable timed model for OWL-S to support modeling the real-time web service in semantic web. In this paper, web service is defined in OWL-S, the standard ontology language of semantic web. Then, in order to formal analyses the time property of web services, Timed CSP which is an extension of Hoare's CSP is utilized to model OWL-S in detail. Finally, Our future working plan is also given in this paper.

We achieved the repositioning of native In adatoms on the polar III-V semiconductor surface InAs(111)A-(2 × 2) with atomic precision in a scanning tunnelling microscope (STM) operated at 5 K. The repositioning is performed by vertical manipulation, i.e., a reversible transfer of an individual adatom between the surface and the STM tip. Surface-to-tip transfer is achieved by a stepwise vibrational excitation of the adsorbate-surface bond via inelastic electron tunnelling assisted by the tip-induced electric field. In contrast, tip-to-surface back-transfer occurs upon tip-surface point contact formation governed by short-range adhesive forces between the surface and the In atom located at the tip apex. In addition, we found that carrier transport through the point contact is not of ballistic nature but is due to electron tunnelling. The vertical manipulation scheme used here enables us to assemble nanostructures of diverse sizes and shapes with the In adatoms residing on vacancy sites of the (2 × 2)-reconstructed surface (nearest-neighbour vacancy spacing: 8.57 Å).

The manipulation of single metallic nanoislands with a precision better than 0.5nm on a MoS2 surface is demonstrated. Optimizing the metal growth conditions yields triangular-shaped nanoislands of 30nm in lateral size and 12nm in height on the MoS2 surface. The manipulation of a single nanoisland was performed using the tip apex of a scanning tunneling microscope. The feedback loop conditions to achieve this manipulation are discussed. Fully planar four-pad nanostructures were constructed, and the apex of each triangular nanoisland of the nanostructure is pointing toward a central 10×20nm2 MoS2 working area where the surface atomic cleanliness is preserved.

The scanning tunneling microscope (STM) has proven to be a powerful technique for probing surface acoustic waves (SAWs) with high spatial resolution. Here we use our ultrahigh-vacuum SAW-STM to investigate a Rayleigh wave excited in LiNbO3 with emphasis laid on the SAW-induced signals at steps that are only a few atomic layers high. Our study reveals that on the length scale of a few nanometer the description of the amplitude and phase contrast by a plain geometrical model fails and a variety of other mechanisms decisively affect the SAW-induced signal. At steps the lateral surface movement due to the SAW may play an important role. For larger step inclination angles also the shape of the STM tip as well as tip-surface interactions become relevant, which may even drive a SAW-induced movement of the tip apex.

Crystalline silicon nitride (SiN x ) thin films on Si(111) and amorphous SiN x films on Si(001) have been obtained after NH3 or NO exposure at T≈1175 K. The crystallinity of the film on Si(111) has been verified with high-resolution cross-sectional transmission electron microscopy (TEM) and scanning tunneling microscopy. The thickness of the SiN x film is 3–6 atomic layers. When compared with the known phases of Si3N4, our SiN x film is relatively close to β-Si3N4, but it could be a new phase of silicon nitride. Si or Ge forms 3D islands initially when deposited on both crystalline and amorphous SiN x films, and most of the islands are not aligned with the Si substrates. However, on SiN x /Si(111), the islands aligned with the Si substrate grow faster than other islands, so that the overlayer gradually grows into a (111)-oriented columnar film. On SiN x /Si(001), the overlayer films remain polycrystalline in later stages of growth.