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Continuous fiber reinforced thermoplastic composites (CFRTPCs) are becoming more significant in industrial applications but are limited by the high cost of molds, the manufacturing boundedness of complex constructions and the inability of special fiber alignment. The purpose of this paper is to put forward a novel three-dimensional (3D) printing process for CFRTPCs to realize the low-cost rapid fabrication of complicated composite components.

For this purpose, the mechanism of the proposed process, which consists of the thermoplastic polymer melting, the continuous fiber hot-dipping and the impregnated composites extruding, was investigated. A 3D printing equipment for CFRTPCs with a novel composite extrusion head was developed, and some composite samples have been fabricated for several mechanical tests. Moreover, the interface performance was clarified with scanning electron microscopy images.

The results showed that the flexural strength and the tensile strength of these 10 Wt.% continuous carbon fiber (CCF)/acrylonitrile-butadiene-styrene (ABS) specimens were improved to 127 and 147 MPa, respectively, far greater than the one of ABS parts and close to the one of CCF/ABS (injection molding) with the same fiber content. Moreover, these test results also exposed the very low interlaminar shear strength (only 2.81 MPa) and the inferior interface performance. These results were explained by the weak meso/micro/nano scale interfaces in the 3D printed composite parts.

The 3D printing process for CFRTPCs with its controlled capabilities for the orientation and distribution of fiber has great potential for manufacturing of load-bearing composite parts in the industrial circle.

Artificial electromagnetic (EM) medium and devices are designed with integrated micro- and macro-structures depending on the EM transmittance performance, which is difficult to fabricate by the conventional processes. Three-dimensional (3D) printing provides a new solution for the delicate artificial EM medium. This paper aims to first review the applications of 3D printing in the fabrication of EM medium briefly, mainly focusing on photonic crystals, metamaterials and gradient index (GRIN) devices. Then, a new design and fabrication strategy is proposed for the EM medium based on the 3D printing process, which was verified by the implementation of a 3D 90o Eaton lens based on GRIN metamaterials.

A new design and manufacturing strategy driven by the physical (EM transmittance) performance is proposed to illustrate the realization procedures of EM medium based device with controllable micro- and macro-structures. Stereolithography-based 3D printing process is used to obtain the designed EM device, an GRIN Eaton lens. The EM transmittance of the Eaton lens was validated experimentally and by simulation.

A 3D 90o Eaton lens was realized based on GRIN metamaterials structure according to the proposed design and manufacturing strategy, which had the broadband (12-18 GHz) and low loss characteristic. The feasibility of 3D printing for the artificial EM medium and GRIN devices has been verified for the further real applications in the industries.

The applications of 3D printing in artificial EM medium and devices were systematically reviewed. A new design strategy driven by physical performance for the EM device was proposed and validated by the firstly 3D printed 3D Eaton lens.

The purpose of this paper is to study the rapid prototyping of porcelain products by using layer‐wise slurry deposition (LSD), in order to reduce the time to market of new or customized porcelain products or artworks.

The properties such as phase composition, microstructure, shrinkage, density, and mechanical strength, of laser sintered (LS) and biscuit fired (BF) samples, before and after post sintering in a furnace, were studied and compared with each other.

The laser sintered sample was comparable with the biscuit fired sample in porosity, but had just half the mechanical strength of the latter due to the layer‐wise fabrication process. The feasibility of rapid prototyping of porcelain products was validated by the successful fabrication of some porcelain samples, which showed that the relatively low mechanical strength of the laser sintered sample was still high enough for the following handling processes, such as surface glazing and glost firing.

The paper demonstrates the possibility of rapid prototyping of porcelain components and the models produced by using LSD process.

The purpose of this paper is to bring up the concept of multi‐material electromagnetic band‐gap structure (EBGs) and develop a method for its fabrication. Meanwhile, its microwave properties were studied and compared with the traditional EBGs consisting of two kinds of material.

Stereolithography (SL) and gel casting were used to fabricate 3D multi‐material EBGs. Resin mold was designed and fabricated based on SL process, slurries loaded with 55vol per cent Al₂O₃ and 55vol per cent TiO₂, respectively, were prepared, and using gel casting, multilayer EBGs with diamond structure were fabricated. T/R method was used to obtain the characteristic parameter S₂₁ of the EBGs; meanwhile, characters of their band structure were studied based on plane wave expansion method.

The fabricated EBGs with a TiO₂‐resin‐air structure showed a band gap from 11.7 GHz to 16.0 GHz along <1, 1, 0> direction; the EBGs with a TiO₂‐resin‐Al₂O₃ structure showed a band gap from 11.4 GHz to 11.9 GHz along <1, 1, 0> direction. Both of them agreed well with the simulation result. Also, through the study of multi‐material EBGs' microwave properties, it could be seen that this structure was a good approach to adjust the band gap.

With the concept of multi‐material EBG structure brought up, multilayer 3D EBGs were designed and fabricated based on SL combined with gel casting. It could be seen that multi‐material EBGs was a good approach to adjust the band gap. Also, the fact that the testing result matched the simulation validates the feasibility of the process.

The purpose of this paper is to present a novel and effective fabricating method of 3D ceramic photonic crystals with diamond structure.

The reverse diamond‐structure resin molds are fabricated by stereolithography (SL), then ceramic slurry is prepared and injected into the molds under vacuum condition. Subsequently, ceramic photonic crystals are obtained after vacuum freeze‐drying and sintering.

The combination of SL, gel‐casting and freeze‐drying could be used to fabricate the 3D ceramic photonic crystals with diamond structure which have intact structure and minimal shrinkage. The samples have been tested and the experimental results indicate that their band gap is in the range of 10.14‐12.20 GHz, consistent with the simulation results.

The influence of fabrication process on the photonic band gap needs further study.

This paper presents a novel fabricating method of 3D diamond‐structure ceramic photonic crystals based on SL, gel‐casting and freeze‐drying. The method fabricates complex ceramic photonic crystals with high accuracy and helps further research in this field.

The purpose of this paper is to investigate the influence of economic policy uncertainty (EPU) on China’s grain futures prices. Related literature has discussed several factors contributing to the dramatic boom and bust in China’s grain futures prices, but has overlooked the influence of EPU.

The study employs a newly developed time-varying parameter vector autoregressive model to study and contrast the impact of different types of uncertainty on China’s grain futures prices. The directional volatility spillover index is used to measure the impact of EPU on China’s grain futures prices and compare the differences among commodities.

The results show that EPU affects China’s grain futures prices significantly. The 2008 global financial crisis had stronger influence on China’s grain futures prices than other types of uncertainty. Furthermore, EPU has smaller influence on wheat futures price than on maize and soybean. The Chinese Government interventions may be the reason for this difference.

This study addresses the lack of empirical investigation on the influence of EPU on China’s grain futures price volatility.

This paper investigates whether China's R&D tax deduction policy triggers firms to manipulate their R&D expenditures upward.

This paper employs the ratio of actual tax savings as a proxy for the benefits of the R&D tax deduction policy based on manually collected and systematically cross-checked data. The relationship between tax benefits and abnormal R&D spending is estimated in a sample of Chinese A-share listed companies for the period 2007–2018.

The findings suggest that tax deductions lead to positive abnormal R&D spending and that this deviation in R&D spending may be attributed to firms' upward R&D manipulation for tax avoidance. The results also indicate that this behavior is more significant for the period after the policy revision, in non-HNTEs (high and new technology enterprises), and in firms with a high ratio of R&D expenses.

It is difficult to establish a sophisticated and unified model to identify the specific strategy of upward R&D manipulation that firms use to obtain tax benefits.

Managers should take into account upward R&D manipulation when designing governance mechanisms. Policymakers in developing countries may further pursue preferential tax policies that cover every stage of innovation activities gradually; the local provincial governments need to leverage their proximity and flexibility advantages to develop a tax collection and administration system.

This study contributes to the understanding of the complex effect of R&D tax incentives and helps more fully illuminate firms' upward R&D manipulation behavior from the perspective of tax planning strategies, which are underexplored in previous research.

Although social networks play an important role in individual ambidexterity, few studies have examined the impact of salespeople's social networks on sales-service ambidexterity. The purpose of this paper is to explore how salespeople's internal and external social networks affect sales-service ambidexterity.

The unique data of 331 salespeople from 39 units in retail banking industry and insurance industry were collected, and the hierarchical linear model was adopted to test the hypotheses. Finally, the alternative measure of the dependent variable and the alternative estimation method were adopted for robustness test.

The results show that the strength of salespeople's internal social networks and the extensiveness of salespeople's external social networks could facilitate sales-service ambidexterity of salespeople separately and synergistically. Salespeople's role breadth self-efficacy partially mediates the influences of internal and external social networks on sales-service ambidexterity, while empowerment climate and transformational leadership positively moderate the aforementioned mediational process by strengthening the relationship between salespeople's role breadth self-efficacy and sales-service ambidexterity.

Practical guidelines are provided for managers to shape ambidextrous salespeople by facilitating salespeople's internal and external social networks, promoting transformational leadership and creating empowerment climate within the unit.

To the best of the author's knowledge, this paper is the first to systematically examine the impact of salespeople's social network on sales-service ambidexterity. Drawing from social cognitive theory and the ambidexterity literature, this research reveals the mechanism of how salespeople's internal and external social networks contribute to sales-service ambidexterity.

One aspect of agency theory suggests that dominant shareholders use the firm’s assets for their personal benefits and 1thus expropriate minority shareholders (tunneling). Accordingly, this paper aims to examine the effect of capital structure and cash holding decisions on minority shareholders' expropriation for short and long periods.

Data of 16 years (2000-2015) has been obtained from 200 non-financial firms registered at Pakistan Stock Exchange (PSX). The study used fixed effect and autoregressive distributed lagged to obtain the results.

The results suggest that the presence of more debts in capital structure is positively associated with minority shareholders' expropriation, whereas a negative association has been found between the level of cash holding and minority shareholders expropriation. These results have been observed as significant both for the short and long run.

This study also suggests some important measures to control minority shareholders' expropriation by the dominant shareholders and thus to protect their rights.

There is a lack of literature for this severe issue in the developing countries especially Pakistan, so this study narrates the potential measures to the regulatory authority of the market to curb tunneling and to protect minority shareholders.