To reduce production cost and inhibit the aggregation of graphene, graphene oxide and copper nitrate solution were used as raw materials in the paper. Cu particles were introduced to the graphene nanosheets by in-situ chemical reduction method in the hydrazine hydrate and sodium hydroxide solution, and the copper matrix composite reinforced with Cu-doped graphene nanosheets were fabricated by powder metallurgy. The synthesized Cu-doped graphene was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The relative density, hardness, electrical conductivity and tensile strength of the copper matrix composite reinforced with Cudoped graphene were measured as well. The results show that copper ions and graphene oxide can be effectively reduced by hydrazine hydrate simultaneously. Most of oxygen functional groups on the Cu-doped graphene sheets can be removed dramatically, and Cu-doped graphene inhibit the graphene aggregation effectively. Within the experimental range, the copper matrix composites have good comprehensive properties with 0.5 wt% Cu-doped graphene. The tensile strength and hardness are 221 MPa and 81.6 HV, respectively, corresponding to an increase of 23% and 59% compared to that of pure Cu, and the electrical conductivity reaches up to 93.96% IACS. However, excessive addition of Cu-doped graphene is not beneficial for the improvement on the hardness and electrical conductivity of copper matrix composite.
Graphene exhibits high carrier mobility and concentration as well as other remarkable properties. Among them, the thermal behaviors of phonon modes play important roles in the application of optical and electronic devices. Here, A–A stacked graphene were proved well by Raman investigation on G and 2D modes. Temperature-dependent Raman scattering measurements on graphene with various number of layers on different substrates were conducted in the temperature range of 80–460 K. The first-order temperature coefficient of single layer graphene (SLG) on SiO2/ Si substrate is obviously smaller than that on Cu foil, indicating that the substrate effect attributes a great impact on graphene phonon temperature dependence. The first-order temperature coefficients of multilayer graphene linearly decrease as the number of layers increases, attributed to the reduction of substrate effect in phonon behaviors, rather than to the anharmonic phonon–phonon (ph–ph) coupling or thermal expansion.
Carbonaceous materials are considered as potential adsorbents for organic dyes due to their unique structures which provide high aspect ratios, hydrophobic property, large efficient surface area, and easy surface modification. In this work, graphene nanoribbons (GNRs) were prepared by atomic hydrogen-induced treatment of single-walled carbon nanotube (SWCNTs), which inspire the idea of cutting and unzipping the SWCNTs carpets with the modified in molecules prevent because of the unfolding of the side-walls. The unfolded spaces and uniform vertical arrangement not only enhance the active surface area, but also promote the electrostatic and π–π interactions between dyes and GNRs. The improved adsorption capacity of GNRs beyond original SWCNTs can be determined by the adsorption kinetics and isotherm, which are evaluated through adsorption batch experiments of the typical cationic methylene blue (MB) and anionic orange II (OII) dye, respectively. It is shown that the adsorption kinetics follow a pseudo second-order model while the adsorption isotherm could be determined by Langmuir model. The results reveal that the maximum adsorption capacities of GNRs for MB and OII are 280 and 265 mg/g, respectively. The GNRs present the highly efficient, cost effective, and environmental friendly properties for the commercial applications of wastewater treatment.
The restaurant industry is more engaged in innovation now. Many entrepreneurs realized that the restaurant sector faces major challenging market environments: changing needs of customers, high competition, low barriers to entry, high labor costs, and innovation technology. The market orientation drives business learning about customers. Engaged customers can assist firms to improve performance by getting involved with the firm’s product innovation. Innovation could help restaurants to improve the products and service quality, cut costs, increase sales and profits; it is the basic condition for the survival of restaurant entrepreneurs. However, studies about how the innovation affects restaurant performance were still limited to describe the overview of products innovation process (Ivkov et al., 2016). Resource-based theory takes the internal resources and capabilities of a firm as valuable sources of competitive advantage. How to combine internal resources and quickly respond to market needs to create performance of innovation entrepreneurship that still unclear and worth exploring in depth discussion. Based on the above, This study personal interview with twelve restaurant entrepreneur, government experts and scholars reveal how absorptive capacity could strengthen the link between positional advantage and innovation for entrepreneurship restaurants with the influence of customer engagement. The positional advantages can make enterprise differentiate with their competitors, that including entrepreneurial orientation, human capital and market orientation (Jogaratnam,2017). The experts believe that innovation entrepreneurs need to adopt an open mind, seek new opportunities in the catering market, acquire or develop new technologies and launching new products / services in the market, using high returns and high risk strategies in search of success in market. Training and educating team members are effective way to improve their innovation entrepreneurship.
Scholars have described compulsive behaviour as “hyperstimulation, sometimes unintentional and repeated overindulgence despite negative consequences, deception and self-neglect” (Hartston 2012). Compulsive buying behaviour has become an addiction amongst many consumers and it has fuelled the growth of the retail market since the 1990’s (Neuner, Raab and Reisch 2005; Koran et al. 2006). The higher spending power of the middle-class consumer has led to a greater demand of luxury branded products so that consumers can attain a higher level of social class within the society. This study will explore the impact of emotional factors (self-esteem, FOMO, brand prestige, and brand consciousness) and rationale factors (product quality, price consciousness and sale proneness) on compulsive buyer’s purchase intention. This is the first study to explore the impact of emotional and rationale factors on compulsive buying behaviour in the luxury branded product category. The results show that young consumers with high compulsive buying tendencies are more heavily influenced by emotional factors. Therefore, retailers could target young consumers by focusing on brand prestige and the brand name.
The antioxidant capacities, total phenolic contents (TPC), and total quercetin contents (TQC) of a red (Chenjujuck), a yellow (Sunpower), and a white (Grasier) onion cultivar were determined in this study. Onion was separated into edible portion and dry skin. In the case of edible portion, the yellow onion had the highest antioxidant activity, followed by the red onion. The white onion showed neither antioxidant activity nor quercetin compounds. On the other hand, the dry skin of the red onion showed higher antioxidant activity than yellow onion skin. The white onion skin had slight antioxidant activity, low TPC, and no quercetin compounds. In addition, the flavonoid compounds of the edible portion and dry skins of these colored onions were analyzed by UFLC(ultra-fast liquid chromatography). The major compounds were quercetin 3,4-diglucoside and quercetin 4- glucoside in yellow and red onion edible portion, whereas the major compounds in yellow and red onion skins were quercetin 4- glucoside, quercetin, and quercetin 3,4-diglucoside.
The surface treatment of C-type isotropic pitch-based carbon fiber was carried out by anodic oxidation in 5 wt% NH4NO3 electrolyte. The changes of fiber surface and carbon fiber/ABS resin composites were characterized by SEM, XPS and mechanical properties test. The oxygen functional groups on the surface, such as hydroxyl (-C-OH), carboxyl (-COOH) groups etc., increased after oxidation. Tensile strength, flexural strength and modulus of carbon fiber/ABS composites were also enhanced. However, the impact strength decreased with the improvement of the surface adhesion between CF and matrix.
In this work, based on our previous calculations of spectral energy distributions for a sample of Fermi blazars (Fan et al. 2015a), we calculated the radio loudness and performed correlation analyses. Our analysis results show that radio loudness is closely anti-correlated with synchrotron peak frequency and positively correlated with gamma-ray luminosity, suggesting that the gamma-ray emissions are strongly beamed.
Four shear-deficient reinforced concrete (RC) beam specimens with different shear span ratios were tested using a well-instrumented drop-weight impact machine to gain a better understanding of the effect of shear span ratio on impact behavior of RC beams strengthened with carbon fibre reinforced polymer (CFRP). The results demonstrated that the shear span ratio could change the failure modes for strengthened specimens and also affect the impact resistance.
This study is focused on three-dimensional nonlinear finite element analysis of reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP) strips under impact loading. The validity of the model was assessed through the comparison with experimental results obtained from drop-weight impact tests of the authors. The well agreement proves the feasibility of the proposed numerical analysis method.