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Spatial Relation is one of the important components of Geographical Information Science and Spatial Database. There have been lots of researches on Spatial Relation and many different spatial relations have been proposed. The relationships among these spatial relations such as hierarchy and so on are complex and this brings some difficulties to the applications and teaching of these spatial relations. This paper summaries some common spatial relations, extracts the topic types, association types, resource types of these spatial relations using the technology of Topic Maps, and builds many different relationships among these spatial relations. Finally, this paper utilizes Java and Ontopia to build a topic map among these common spatial relations, forms a complex knowledge network of spatial relations, and realizes the effective management and retrieval of spatial relations.

The parabolic equation (PE) method is a good choice in solving large-scale problems, but the resultant matrix is usually ill conditioned. In this letter, we introduce the geometric optics (GO) management in the calculation of bistatic radar cross sections using three-dimensional vector PE method. This method manages the object surface by GO, and hence the ill-conditioned problem can be avoided. Examples are given using the presented method, original method, and the method of moments. Results show the validity and stability of the presented method.

OBJECTIVE: Recent researches have proved that circular RNAs (circRNAs) act as an important role in many diseases. Our study aims to uncover the role of circ-ABCB10 in the progression of non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was utilized to detect circ-ABCB10 expression in NSCLC patients. Then, we conducted Cell Counting Kit-8 (CCK-8) assay, colony formation assay, Ethynyl deoxyuridine (EdU) incorporation assay, cell cycle assay, and cell apoptosis assay in treated NSCLC cells. Besides, further experiments including RT-qPCR and Western blot assay were performed to explore the potential mechanism in vitro. RESULTS: Circ-ABCB10 expression level was significantly higher in NSCLC samples comparing to that in adjacent tissues. Moreover, functional assays showed that the cell growth ability of NSCLC cells was inhibited after circ-ABCB10 was knocked down. In addition, the cell apoptosis of NSCLC cells was promoted after circ-ABCB10 was knocked down. Also the expression of KISS1 was upregulated by the knockdown of circ-ABCB10. Furthermore, it was found that KISS1 expression was negatively correlated to the circ-ABCB10 expression in NSCLC tissues. CONCLUSIONS: Results above indicated that circ-ABCB10 promoted cell proliferation and inhibited cell apoptosis of NSCLC by suppressing KISS1, which suggested that circ-ABCB10 may be a potential therapeutic target in NSCLC. [ABSTRACT FROM AUTHOR]

We present a thin metasurface with large microwave absorptivity and low infrared emissivity simultaneously. By properly tuning the resonance peaks and impedance of the meta-atom, broadband microwave absorptivity greater than 90% from 8.2 to 16.0 GHz is achieved. In the meantime, owing to large coverage of periodic metal patches on the top surface, low infrared emissivity is exhibited in the infrared region (IR) of 8 µm–14 µm. The excellent agreement between numerical simulation and experimental result demonstrates the good performance of the proposed metasurface. Due to the usage of polymethacrylimide (PMI) and polyethylene terephthalate (PET) as the substrate, the metasurface is especially advantageous for the light weight, making it a favorite in real engineering applications. [ABSTRACT FROM AUTHOR]

We propose a kind of stereometamaterial composed of periodic structures with twisted asymmetrical split-ring (ASR) resonators. The proposed stereometamaterial has intrinsic chirality and can be used as a multiband polarization spectral filter. Full-wave simulation and experimental results demonstrate that the stereometamaterial with the twist angle οfϕ = 90° exhibits three ripple-free cross-polarization transmission peaks at normal incidence of plane waves. The cross-polarization transmission bands are centered at the maxima of circular dichroism, accompanied by pairs of pure circular birefringence points. In physics, the near-field electric and magnetic coupling of orthogonal ASR molecules in parallel planes contributes to the conversion of two orthogonal linear polarizations. The transmission of the proposed multiband polarization spectral filter can be engineered via the mutual twist angle and asymmetry of the ASRs and the thickness of the dielectric spacer layer and also be tuned via the angle of incidence. [ABSTRACT FROM AUTHOR]