Search

The coastal zone is essential to economic and social development. However, coastline evolution is a complex research topic, owing to the intersection and coupling of different fields such as wind, wave, and current. Research is further complicated by variations in these fields’ temporal and spatial scales. This study acquired and preprocessed multi-phase Landsat remote sensing satellite images of the eastern coast, from Wailuo to Zhuzi, from 1987 to 2021. Then, the decoded and extracted instantaneous coastline images were corrected, and quantitative analysis was carried out through the Digital Coastline Analysis System (DSAS). The results showed that trends of coastline evolution in the study area in the medium–long term were overall balanced. All the transects manifested temporal and spatial differences, and erosional hot spots were mainly concentrated on the coastal cape and its vicinity. To investigate storm-induced beach erosion in the short term, the 400 m coastline of Baimao in the area was selected as a field site, and the field survey was conducted during two storms. The distribution of the dynamic parameters of sediment deposition was also investigated. The results showed that the beach in the field site had an excellent ability to resist storm erosion and that the topographic change was greatly affected by geological conditions in the area, such as reef masking and a typical headland beach. The grain size parameters of the beach sediments were sensitive to storms, reflecting the adjustment of the beach surface during typhoons. This study shows how a multi-timescale analysis could represent an efficient approach to understanding the dynamic evolution of the coastline. It showed a detailed description of the historical coastline evolution of the eastern coast of the Leizhou Peninsula after 1987. Additionally, the coastline evolution and sediment distribution for the sedimentation dynamic environment of Baimao tourist area in the short term were also investigated. In conclusion, this study can contribute to the rational utilization of coastal resources, to coastal disaster prevention, and the mitigation of local coastal areas.

An extended object-oriented petri net (EOOPN) supporting the description and evolution of components in the context of intelligent and cloud computing is proposed in this paper. EOOPN can tersely and independently represent all kinds of resources and restrains in a complex system, and reveal structural and behavioral information of simulated system. The modeling and analyzing power that EOOPN possesses enables it to be a tool which is capable of supporting component-based software evolution process under the circumstances of cloud computing. The formal definition of EOOPN is given and a wide range of object-oriented features supported by EOOPN are explained. Moreover, a roadmap of using EOOPN to evolving software components is discussed.

The growth of cases of nosocomial infections is an urgent issue in health care facilities. Reducing cross-contamination from high-frequency touch surfaces is a key area of interest. Robust TiO2 coatings on touch surfaces could reduce pathogen viability if the material could be modified to increase photocatalytic activity (PCA) under visible light. Research has focused on increasing the bandgap by use of dopants and rutile-anatase heterojunctions, using nanoparticles to increase active surface area, and sensitizing TiO2 with carbon. We have previously reported 11 μm thickness nanostructured anatase and rutile mixed phase TiO2 and carbon composite coatings (NsARC) which are antimicrobial under visible light. Here we investigate the role of the co-deposited carbon in the antibacterial performance. Coatings of 4.0–6.0 μm thicknesses nanostructured anatase were deposited by pulsed-pressure metalorganic chemical vapor deposition (pp-MOCVD) on stainless steel and glass substrates, and one set was heat-treated to remove the co-deposited amorphous carbon. Morphology, phase and adhesion were not affected by the short heat treatment at 500 °C in air. The water contact angle was reduced under visible light to a much greater extent for the carbon-free sample. The antimicrobial performance of the coatings was marginally enhanced by removing the carbon. While the carbon may be enhancing the visible light PCA of the TiO2, we conclude that it is also interfering with the transport of radical oxygen species to the bacteria and reducing the active surface area.

Base on the Extended Object-Oriented Petri Net, and the component evolution processes that has been proposed in our previous research, this paper studies the component assembling technique based on the EOOPN subnet combination. The definition of sequential assembling, a type of connector-based EOOPN-CN assembling approach, is given and subsequently its properties and proof is detailed. This paper’s work laid foundations for the further presentational and analytical aspects of component evolution.

In this paper, anodization of NiTi was carried out in a viscous fluorine ion containing ethylene glycol electrolyte, with the objective of investigating the influence of anodization conditions on the surface properties. The surface morphologies and chemical compositions of the anodized NiTi surfaces were characterized by using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Nanosized oxides with evenly distributed pores were observed on the anodized NiTi surfaces. The pore size and shape depended on the anodization conditions. This oxide layer formed on the anodized NiTi surface was mainly composed of TiO 2 , with significantly reduced Ni content. The surface roughness and wettability of anodized NiTi surfaces were also greatly enhanced. Moreover, the anodized NiTi surface showed an improved antibacterial activity with Escherichia coli . The present study indicates that anodization of NiTi in an ethylene glycol based electrolyte is an efficient method to modify the surface microstructure as well as surface chemistry of NiTi for biomedical applications.

Many diseases spread due to the bacterial infections, which cause significant economic and personal losses. Contact with infected surfaces is likely to catch infections. Hence, antimicrobial surfaces play an important role in public sectors that can prevent the spreading of disease and infection. Coatings on contact surfaces have been used to provide antimicrobial function. Copper (Cu), as one of the commonly used metals, has long been known to possess germ-killing properties. However, metallic Cu or Cu coatings have not been widely used for the purposes of antimicrobial due to the heavy weight, relatively high cost, limited corrosion resistance and low compatibility of the metal with substrates of non-metallic materials. We have recently developed a polymer-based coating system containing mixtures of fine particles of Cu and Cu salt, which provides excellent antimicrobial properties. The results indicate that the coating with embedded fine Cu salt showed higher antimicrobial property than the coating with only Cu due to the release of more Cu ions. The elimination of 10(6) bacteria by contacting the polymer-Cu coatings needs 8 h, while contacting with the polymer-CuCl2 coatings took only 20 min to kill the same amount of bacteria. We have also used transmission electron microscopy and synchrotron infrared microscopy technique to study the degradation of bacterial cell membrane to understand the mechanism of the antimicrobial function of Cu coating.

Copper (Cu) containing coatings can provide sustainable protection against microbial contamination. However, metallic Cu coatings have not been widely used due to the relatively high cost, poor corrosion resistance, and low compatibility with non-metal substrates. Titanium dioxide (TiO 2 ) possesses antibacterial functions by its photocatalytic properties which can destroy bacteria or suppress their reproduction. TiO 2 also has the function of improving the mechanical properties through particle dispersion strengthening. We have recently developed an innovative polymer based coating system containing fine particles of Cu and TiO 2 nanoparticles. These polymer based coatings simultaneously display excellent antimicrobial and good mechanical properties. The results showed that the addition of TiO 2 has improved the antimicrobial property under sunlight, which provides extended applications in outdoor environment. The elimination of 10 6 bacterial by contacting the coatings without TiO 2 needs 5 h, while contacting with the Cu/TiO 2 – 1 wt.% TiO 2 took only 2 h to kill the same amount of bacteria. The coatings also presented enhanced hardness and wear resistance after adding TiO 2 . The width of wear track decreased from 270 μm of the Cu-polymer coating to 206 μm of Cu/TiO 2 -polymer coatings with 10 wt.% TiO 2 . Synchrotron Infrared Microscopy was used to in-situ and in-vivo study the bacteria killing process at the molecular level. The real-time chemical images of bacterial activities showed that the bacterial cell membranes were damaged by the Cu and TiO 2 containing coatings

Based on the Extended Object-Oriented Petri Net, and the component evolution processes that has been proposed in our previous research, the notion of Stochastic Petri Net (SPN) is integrated into EOOPN to facilitate the time aspect of system performance analysis. To simplify the complexity of time performance analysis, the system is further divided into layer subsystems so that the issue of state space explosion leading to immense increasing in computational complexity is avoided.

This paper studies the issue of component refinement on the bases of component evolution processes that has been proposed in authors previous research work focused on Extended Object-Oriented Petri Net. Components are refined through basic elements of software system's architectural components. The detailed idea of component refinement is discussed and a set of methods and rules relating to component refinement are provided under the framework of EOOPN model.

Base on the Extended Object-Oriented Petri Net, and the component evolution processes that has been proposed in our previous research, this paper applies the top-down and bottom-up strategy to stratify component models. The definition of Equivalent Model of EOOPN is given, four types of subnet Equivalent Model are analyzed and the system performance analysis methodologies corresponding to the four types of subnet are discussed.

Base on the Extended Object-Oriented Petri Net, and the component evolution processes that has been proposed in our previous research, this paper studies the issue of component refinement. Three types of component refinement under the framework of EOOPN model, namely ABP refinement, ABT refinement and Token refinement, are proposed in this paper along with their definitions and component features before and after the processes of refinement.

Copper ( Cu ) is widely used as electrical conducting and contacting material. However, Cu is soft and does not have good mechanical properties. In order to improve the hardness and wear resistance of Cu , sol-enhanced Cu – Al 2 O 3 nanocomposite coatings were electroplated by adding a transparent Al oxide ( Al 2 O 3) sol into the traditional electroplating Cu solution. It was found that the microstructure and mechanical properties of the nanocomposite coatings were largely influenced by the Al 2 O 3 sol concentration. The results show that the Al 2 O 3 nanoparticle reinforced the composite coatings, resulting in significantly improved hardness and wear resistance in comparison with the pure Cu coatings. The coating prepared at the sol concentration of 3.93 mol/L had the best microhardness and wear resistance. The microhardness has been improved by ~20% from 145.5 HV (Vickers hardness number) of pure Cu coating to 173.3 HV of Cu – Al 2 O 3 composite coatings. The wear resistance was also improved by ~84%, with the wear volume loss dropped from 3.2 × 10-3 mm3 of Cu coating to 0.52 × 10-3 mm3 of composite coatings. Adding excessive sol to the electrolyte deteriorated the properties.

In this paper, Nitinol, an equiatomic binary alloy of nickel and titanium, was surface modified for its potential biomedical applications by chemical and electrochemical etching. The main objective of the surface modification is to reduce the nickel content on the surface of Nitinol and simultaneously to a rough surface microstructure. As a result, better biocompatibility and better cell attachment would be achieved. The effect of the etching parameters was investigated, using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX) and X-ray photoelectron spectrometry (XPS). The corrosion property of modified Nitinol surfaces was investigated by electrochemical work station. After etching, the Ni content in the surface layer has been reduced and the oxidation of Ti has been enhanced.