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This study aims to obtain the mechanistic insights for the fabrication of pure copper thin wall components by selective infrared (IR) laser melting (SLM) and correlated with microstructure development, microhardness, surface morphology and phase analysis. Experimental processes for single track and selection of substrate materials have been studied using a combination of different laser powers and scanning speeds.

SLM of pure copper was performed on a YONGNIAN Laser YLMS-120 SLM machine using an Nd: YAG fiber laser operating at 1,060 nm in the NIR region. Single-track experiments and processing parameters are investigated through different combinations of laser power and scanning speed. The microstructure of the fabricated pure copper samples by SLM technique was analyzed by means of X-ray diffraction, scanning electron microscope equipped with energy disperse spectrometer, optical microscope (OM) and micro-hardness tester.

Steel-based substrates were found suitable for pure copper manufacturing due to sufficient heat accumulation. The width of a single track was determined by liner energy density, showing discontinuities and irregular morphologies at low laser powers and high scanning speeds. As a result of instability of the molten pool induced by Marangoni convection, cracks and cavities were observed to appear along grain boundaries in the microstructure. The top surface morphology of SLM-processed component showed a streamflow structure and irregular shapes. However, the powder particles attached to side surface, which manifest copper powders, are even more sensitive to melt pool of contour track. The crystal phase characteristics of copper components indicated increasing crystallite size of a-Cu, and the decreasing intensity of diffraction peak was attributed to the presence of defects during SLM. The maximum relative density and microhardness were 82 per cent and 61.48 HV0.2, respectively. The minimum thickness of a pure copper thin wall component was 0.2 mm.

This paper demonstrated the forming mechanism and explored feasibility of pure copper thin wall parts by SLM technology in the NIR region. The surface morphology, microstructure and crystal structure were preliminary studied with laser processing parameters.

This paper introduces a new subject called bio‐manufacturing. Bio‐manufacturing combines life science with manufacturing science, and uses manufacturing method to form materials with bio‐activity and bio‐degradability into scaffolds. In this paper, we discuss the hierarchy of bio‐manufacturing: the lower grade uses undegradable bio‐material to form permanent organ replacement such as auricular cartilage and the higher grade uses biodegradable bio‐materials to repair organ damage or organ replacement which degrades after embedded in the human body. They all adopt jetting/extrusion deposition process (fused deposition modelling or 3D printer), the distinct different point being the temperature of the forming chamber. The samples of bones and auricular cartilage produced by those processes had been practiced on dogs and rabbits, repaired their damage.

A mathematical model to predict the layered process error and an optimization algorithm to define the fabricating orientation based on the minimum process error for layered manufacturing fabrication has been developed. Case studies to determine the preferred orientation candidates for fabricating spherical objects, cube objects and objects with irregular geometrical shapes have been conducted and the results were used to validate the sensitivity, accuracy, and capability of the developed model and optimization algorithm. Different orientation candidates determined by minimum processing error and by minimum processing time were also compared. The developed model and the optimization algorithm can be used, in conjunction with other processing parameters such as processing time and support structure, to define an optimal processing planning for layered manufacturing fabrication.

A mathematical model to describe the principle of layered manufacturing and layered fabrication error is presented in this paper. In this model, the layered manufacturing process is characterized by the model decomposition and material accumulation. A 3D design model is represented by a set of points with sequence functions to correlate the layered processing information. Iso‐sequence planes are defined as the processing layers to collect points with the same processing sequence and to define the material accumulation along its gradient direction. Examples of using the proposed model to describe the layered manufacturing to process flat and no‐flat surfaces and the description of the layered processing error are also presented.

Multi‐functional rapid prototyping manufacturing system (M‐RPMS) is an important potential developing field and tendency of RP technique. Application area of the M‐RPMS has been discussed in this paper. It is believed that the M‐RPMS has to be developed both for industrial and academic purposes. The openness of software and hardware, the diversity of RP processes and the highest function/cost ratio are the outstanding speciality of the M‐RPMS. This paper also introduces the design principle of the M‐RPMS, the calculation method for function integration degree (FID), the running of SLS in the M‐RPMS and the key of early stage rapid feedback design system.

Aims to provide information on organism manufacturing engineering (OME), a newly proposed interdisciplinary research area.

A conceptual discussion and approach are taken.

OME is based on layer‐by‐layer RP principles and the integration of the new advancement of manufacturing science, biomaterials, cell molecular biology and developmental biology. OME aims to construct live tissues and organs through controlled assembly of 3D cell structure with the principles and methods of modern manufacturing science and life science.

Focuses on important processes for indirect and direct cell assembly using OME approaches.

This study aims to study the distribution characteristics of antibiotic resistance in direct-eating food and analysis of Citrobacter freundii genome and pathogenicity. Residual antibiotics and antibiotic resistance genes (ARGs) in the environment severely threaten human health and the ecological environment. The diseases caused by foodborne pathogenic bacteria are increasing daily, and the enhancement of antibiotic resistance of pathogenic bacteria poses many difficulties in the treatment of disease.

In this study, six fresh fruits and vegetable samples were selected for isolation and identification of culturable bacteria and analysis of antibiotic resistance. The whole genome of Citrobacter freundii isolated from cucumber was sequenced and analyzed by Oxford Nanopore sequencing.

The results show that 270 strains of bacteria were identified in 6 samples. From 12 samples of direct food, 2 kinds of probiotics and 10 kinds of opportunistic pathogens were screened. The proportion of Citrobacter freundii screened from cucumber was significantly higher than that from other samples, and it showed resistance to a variety of antibiotics. Whole genome sequencing showed that Citrobacter freundii was composed of a circular chromosome containing signal peptides, transmembrane proteins and transporters that could induce antibiotic efflux, indicating that Citrobacter freundii had strong adaptability to the environment. The detection of genes encoding carbohydrate active enzymes is more beneficial to the growth and reproduction of Citrobacter freundii in crops. A total of 29 kinds of ARGs were detected in Citrobacter freundii, mainly conferring resistance to fluoroquinolones, aminoglycosides, carbapenem, cephalosporins and macrolides. The main mechanisms are the change in antibiotic targets and efflux pumps, the change in cell permeability and the inactivation of antibiotics and the detection of virulence factors and ARGs, further indicating the serious risk to human health.

The detection of genomic islands and prophages increases the risk of horizontal transfer of virulence factors and ARGs, which spreads the drug resistance of bacteria and pathogenic bacteria more widely.

Since One Belt One Road (OBOR) was proposed, Singaporean sides have reacted differently. Based on the case of Zaobao, the authors develop the theoretical frame including international relations, agenda setting and media framing, analyzing the construction of textual materials on OBOR and its influencing factors.

In this sense, this paper attempts to use Zaobao's texts on OBOR from 2015 to 2017 as textual materials, by using the discourse analysis method and combining the theories of international relations, agenda setting and media framing, to explore the following two relevant questions: How does the mainstream Chinese media of Singapore construct OBOR issue? What factors influence this kind of construction?

The study finds that agendas setting on OBOR are diversified in the purpose of supporting official position and meeting audiences' expectations, which are constrained by the factors such as international situations, regional strategies, national interests and domestic politics. The authors learn more details about hidden and vague thoughts on OBOR from all sides in Singapore through this discourse analysis.

In summary, the academic community has a certain foundation for the study of the cognition of the “Belt and Road” initiative. However, compared with the other countries' research on the Belt and Road cognition, the research on Singapore is insufficient. Singapore is an important hub for the 21st Century Maritime Silk Road. At the same time, as a leader of Association of Southeast Asian Nations (ASEAN), it has a strong appeal and influence in other ASEAN countries. It has also played a pivotal role in building the “Belt and Road”. However, the “Belt and Road” initiative has been proposed and implemented for five years. The research on Singapore's cognition and reaction of the “Belt and Road” initiative is still insufficient. Therefore, an in-depth study of Singapore's cognition of the ‘Belt and Road” initiative has significant academic and applied value. This paper attempts to explore the construction of the “One Belt, One Road” initiative by Singapore's official media to make up for the shortcomings of existing research.

This paper aims to propose a suitable atomizing solidification chitosan (CS) gel liquid extrusion molding technology for the three dimensional (3D) printing method, and experiments verify the feasibility of this method.

This paper mainly uses experimental means, combined with theoretical research. The preparation method, solidification forming method and 3D printing method of CS gel solution were studied. The CS gel printing mechanism and printing error sources are analyzed on the basis of the CS gel ink printing results, printing performance with different ratios of components by constructing a gel print prototype, experiments evaluating the CS gel printing technology and the effects of the process parameters on the scaffold formation.

CS printing ink was prepared; the optimal formula was found; the 3 D printing experiment of CS was completed; the optimal printing parameters were obtained; and the reliability of the forming prototype, printing ink and gel printing process was verified, which allowed for the possibility to apply the 3 D printing technology to the manufacturing of a CS gel structure.

This study can provide theoretical and technical support for the potential application of CS 3 D printed gels in tissue engineering.