In this study, the refinement of Multiwalled Carbon Nanotubes (MWCNTs) derived from chemical vapor decomposition is investigated. An ultrasonic pretreatment method is employed to disentangle carbon and metal impurities intertwined with MWCNTs. The pretreated MWCNTs exhibit a marginal decrease in C–O/C = O content from 8.9 to 8.8%, accompanied by a 2.5% increase in sp3 carbon content, indicating a mildly destructive pretreatment approach. Subsequently, selective oxidation by CO2 and hydrochloric acid etching are utilized to selectively remove carbon impurities and residual metal, respectively. The resulting yield of intact MWCNTs is approximately 85.65 wt.%, signifying a 19.91% enhancement in the one-way yield of pristine MWCNTs. Notably, the residual metal content experiences a substantial reduction from 9.95 ± 2.42 wt.% to 1.34 ± 0.06 wt.%, representing a 15.68% increase in the removal rate. These compelling findings highlight the potential of employing a mild purification process for MWCNTs production, demonstrating promising application prospects.

Metaverse provides technology for people to connect, find communities, and grow businesses. Its sales have seen growth during the COVID-19 pandemic. In an era of metaverse, luxury brands such as Gucci, Ralph Lauren, Burberry, Balenciaga, and Dolce & Gabbana are trying to adapt to new changes. They launched NFT(Non-fungible token) goods, digital fashion, and virtual luxury goods on various metaverse platforms such as Zepeto, Roblox, and Fortnite. For example, Ralph Lauren in Zepeto provides various types of luxury items, immerses in virtual performances, and has a game plot interaction. As people immerse themselves in the Metaverse, they feel happy from various activities—such as watching advertisements, drinking juice, and playing with friends. Thus, what factors should be considered when the luxury brands manage the metaverse?

Metaverse blends the physical and virtual worlds, transforming the customer's shopping experience. This study aims to identify the psychological mechanism in the metaverse environment and the relationship between metaverse experience and consumer happiness. To identify metaverse experiences, both behavioral and functional magnetic resonance imaging (fMRI) studies were conducted. In a behavioral study, we found that consumers' happiness increased when participants were in an immersive metaverse space. In the fMRI study, we found greater activation in the medial prefrontal cortex (MPFC) and lateral occipital cortex (LOC) regions in the high level of the immersive metaverse and found a positive relationship with consumers' happiness. This paper is the first attempt in marketing to provide an integrative brain map for the metaverse experience. This brain map helps marketers better understand the consumer experience. This study suggests that only in the immersive metaverse space where virtual and physical experiences interact can consumers become one with the virtual space and maximize customer experience values.

In order to solve the problem of improper thrust distribution of each thruster of underwater vehicle, the PSO optimization algorithm is used to solve the problem of thrust distribution. According to the spatial layout of the thruster, the algorithm model of the underwater vehicle propulsion system is established. The thrust input is carried out under the broken line search trajectory, and the simulation verifies the thrust allocation results of the PSO algorithm and the traditional pseudo-inverse method. The simulation results show that compared with the traditional algorithm. First of all, the PSO algorithm can set the physical threshold for each thruster to prevent the thruster from having too much thrust. Secondly, it can ensure that the thruster can turn with a reasonable torque to prevent the robot from drifting due to the large thrust gap. This paper provides a theoretical reference for thrust distribution of underwater salvage robot, and has practical engineering significance.

The carbon-containing molecule can be used as an NMR probe to explore the acidic and structural features of various catalytic materials. Thereinto, although mesityl oxide (MO) has been extensively employed to determine the acidity of solution and ionic liquid systems, could it be utilized to characterize the acidic properties of solid acid catalysts? In this work, on the basis of a series of isolated Brønsted and Lewis acid models with varied acid strengths, the adsorption configurations and corresponding 13C chemical shifts of adsorbed MO molecules have been comprehensively studied by means of a theoretical investigation approach. Among them, both the 13C chemical shift difference between β and α carbon atoms (Δδ), and the 13C chemical shift of β carbon atoms (δ13Cβ) in adsorbed MO molecules were explicitly demonstrated to be closely related to the intrinsic acid strength of Brønsted acid sites. These correlations could be utilized to quantitatively scale the Brønsted acid strength of solid acid catalysts. Besides, a moderate relationship was theoretically derived for the relevant 13C NMR parameters and intrinsic Lewis acid strength.

For applications in cement-based materials, studies on carbon-based nanomaterials have been almost exclusively on carbon nanotubes, carbon nanofibers, and graphite oxide. Graphene sheets (GPs), as a kind of carbon-based nanomaterials, show unusual mechanical, electrical, optical, and other properties. In this paper, the main focus is to enhance the effect of GPs by improving dispersion through ultrasonication and use of surfactant. Then, dispersion and stability are quantitatively measured by comparing absorbance spectra through spectrophotometry and qualitatively observed through digital imaging and SEM imaging. Therefore, the dispersing protocol is optimized and the most effective and stable dispersion is achieved. At last, the piezoresistivities under compressive load of GPs/cement composites pastes at different additions of GPs are studied by comparing with plain cement paste.

Nostalgia refers to the sentimental longing for the valued past (Sedikides, Wildschut, & Baden, 2004). It is considered a bittersweet emotion, involving both wistful joy and sadness (Sedikides et al., 2004). Nostalgia is also a social emotion. Nostalgic memories typically center on social activities involving the self and close others (Wildschut et al., 2010). Prior research has mainly focused on the social and emotional nature of nostalgic narratives, and researchers have only recently started to investigate the motivations triggered by the process of recalling nostalgic narratives. For example, recalling a nostalgic event can heighten people’s motivation to savor such an experience and prolong it (Huang, Huang, & Wyer, 2016). In the current research, we posit that thinking about nostalgic events can trigger another motivation, namely, a desire to revive the past. Whenever people experience nostalgic feelings, they are likely to perceive differences between the present and their memorable past and desire to go back in time (Hepper et al., 2012; Sedikides et al., 2004). This motivation, once activated, can lead people to take actions to change their current state in the hope of reviving the past (Koole & Jostmann, 2004; Kuhl, 1985). This tendency of taking actions to make changes may generalize to subsequent unrelated situations (Kruglanski et al., 2002), and consequently increase consumer switching behavior (Jiang, Zhan, & Rucker, 2014). These predictions were tested across five studies in various consumption contexts. Our findings contribute to consumer research in two important ways, (a) by demonstrating a novel motivational impact of nostalgia on consumer behavior, and (b) by delineating a systematic influence of an unexplored but pervasive emotional factor— nostalgia—on consumer switching behavior. This research also offers practical implications. Conventional wisdom suggests that nostalgia can make consumers prefer products reminiscent of the “old days”. Our findings show that nostalgia can have broader implications for consumer choices and marketers may use it to manage consumer switching behavior.

Using the volume-limited Main galaxy sample constructed from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we explore the environmental dependence of the fraction of ‘unconventional’ galaxies: luminous blue and faint red. It is found that the fraction of faint red increases apparently with increasing local density, and the fraction of luminous blue declines substantially with increasing local density, which shows that there is an environmental dependence for color beyond that for luminosity.