Theoretical Investigation of the Influence of Wavelength on the Bandwidth in Multimode W-Type Plastic Optical Fibers with Graded-Index Core Distribution

The bandwidth of multimode W-type plastic optical fibers (POFs) with graded-index (GI) core distribution is investigated by solving the time-dependent power flow equation. The multimode W-type GI POF is designed from a multimode single-clad (SC) GI POF fiber upon modification of the cladding layer of the latter. Results show how the bandwidth in W-type GI POFs can be enhanced by increasing the wavelength for different widths of the intermediate layer and refractive indices of the outer cladding. These fibers are characterized according to their apparent efficiency to reduce modal dispersion and increase bandwidth.

AN ANALYSIS METHOD OF THE AMOUNT OF BRICKS USED IN PUZHOU ANCIENT CITY WALL BASED ON SLAM

The calculation of the amount of bricks used in the area of falling-off is of great significance to the restoration of the ruins of ancient cities In order to support the digital restoration of the city wall of Puzhou Ancient City Site, this paper analyzed and calculated the amount of outer cladding brick of the city wall based on SLAM data. Firstly, the point cloud data of Puzhou city wall is obtained by SLAM technology. Secondly, the original point cloud is processed by Geomagic Studio software, and the area of the damaged area is accurately measured from the packaging model. Finally, based on the characteristics of brick masonry of ancient city walls, this paper estimates the amount of brick used in the area where the external wall of drum tower falls off, thus providing data support for the repair and maintenance of Puzhou ancient city.

Assessment of the Cement Plate Building Covering Facade

The article deals with the methodology of the assessment of the state of the external facade of the outer cladding façade from the fiber cementitious boards in view of meeting the conditions of the technical legislation valid in the Czech Republic. On a particular case, the methodology of the procedure from the visual assessment of the facade facing plates to the requirements of their mechanical and physical properties is described. The object under consideration is a civic building in a climatically challenging location in the Beskydy foothills, whose facade is completely lined with fiber-cement boards. The assessment is based on the provisions of ČSN ISO 13822 (73 0038): Design principles for structures - Evaluation exists. construction and ČSN P 74 7251: 2015 Folded cladding, tiles and panel cladding - Requirements for casting accuracy, quality and appearance. For the assessment of mechanical and physical properties, the provisions of ČSN EN 12467 - Fiber-cement flat plates - Specimen specification and test method are used. Limit values ​​of individual parameters are taken into account in the technical sheets of the manufacturer of fiber-cement boards.

Efficient blue luminescence from colloidal CdSe quantum-dot quantum-well nanocrystals

ABSTRACTCdS/CdSe/ZnS quantum dot quantum well (QDQW) nanocrystals were synthesized using the successive ion layer adsorption and reaction technique. CdSe QWs with a well width of 1.05 nm emitted blue light at 467 nm with a spectral full-width-at-half-maximum of ∼30 nm. It was found that a 3-monolayer ZnS outer cladding layer can effectively passivate the QDQW structures, leading to a ∼35% quantum yield (QY) of the QW photoluminescence. QDQW light-emitting diodes (LEDs) with blue QW electroluminescence (EL) were fabricated. The devices with an emitting layer comprising QDQWs embedded in a poly(N-vinylcarbazole) host were five times brighter than LEDs based on closely-packed QDQWs. However, the overall EL of the devices was dominated by interface state emission due to poor charge injection into the QDQWs.