Direct Investigation of Superparamagnetism in Co Nanoparticle Films

A direct probe of superparamagnetism was used to determine the complete anisotropy energy distribution of Co nanoparticle films. The films were composed of self-assembled lattices of uniform Co nanoparticles 3 nm or 5 nm in diameter, and a variable temperature scanning-SQUID microscope was used to measure temperature-induced spontaneous magnetic noise in the samples. Accurate measurements of anisotropy energy distributions of small volume samples will be critical to magnetic optimization of nanoparticle devices and media.Comment: 4 pages, 4 figures. Submitted to Physical Review Letter

Research Orientations

Thirty-seven articles can be divided into three categories: 1) Business and Management, 2) Collaborative Consumption and Collaborative Economy, 3) Marketing and Consumption

Can shared micromobility programs reduce greenhouse gas emissions: Evidence from urban transportation big data

Shared micromobillity has been extensively developed globally in the past few decades, but its impact on the environment remains unclear. This study quantitatively estimates the effects of global shared micromobillity programs on greenhouse gas (GHG) emissions using a life cycle assessment (LCA) perspective. Specifically, it takes major countries and cities around the world as examples to empirically analyze the impact of station-based bike-sharing (SBBS), free-floating bike-sharing (FFBS), free-floating e-bike sharing (FFEBS), and free-floating e-scooter sharing (FFESS) programs on the GHG emissions of urban transportation. The results show that, with the exception of SBBS, the other shared micromobillity programs have not achieved desirable GHG emissions reduction benefits. Contrarily to subjective expectations, although the rapid progress of technology in recent years has promoted the vigorous development of shared micromobility, it has brought negative impacts on the GHG emissions rather than the positive benefits claimed by related promoters and operators. The overcommercialization and low utilization rate makes shared micromobility more likely to be an environmentally-unfriendly mode of transportation. In addition, the regional differences in mode choice, operational efficiency, fleet scale, and market potential of shared micromobility and the corresponding impacts on GHG emissions vary greatly. Therefore, authorities should formulate appropriate shared micromobility plans based on the current conditions and goals of the region. This empirical study helps to better understand the environmental impact of the global shared micromobility program and offers valuable references for improving urban sustainability

Exchange Bias Effect in Au-Fe3O4 Nanocomposites

We report exchange bias (EB) effect in the Au-Fe3O4 composite nanoparticle system, where one or more Fe3O4 nanoparticles are attached to an Au seed particle forming dimer and cluster morphologies, with the clusters showing much stronger EB in comparison with the dimers. The EB effect develops due to the presence of stress in the Au-Fe3O4 interface which leads to the generation of highly disordered, anisotropic surface spins in the Fe3O4 particle. The EB effect is lost with the removal of the interfacial stress. Our atomistic Monte-Carlo studies are in excellent agreement with the experimental results. These results show a new path towards tuning EB in nanostructures, namely controllably creating interfacial stress, and open up the possibility of tuning the anisotropic properties of biocompatible nanoparticles via a controllable exchange coupling mechanism.Comment: 28 pages, 6 figures, submitted to Nanotechnolog

Electro-Oxidation of Formic Acid Catalyzed by FePt Nanoparticles

The electrocatalytic oxidation of formic acid at a gold electrode functionalized with FePt nanoparticles was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a mixed solution of 0.1 M HCOOH and 0.1 M HClO 4 . The FePt bimetallic nanoparticles, with a mean diameter of 3 nm, were prepared by a chemical reduction method. The Au/FePt nanostructured electrode was prepared firstly by the deposition of FePt nanoparticles onto a clean Au electrode surface, followed by ultraviolet ozone treatment to remove the organic coating. In CV measurements, two well-defined anodic peaks were observed at þ0.20 and þ0.51 V (vs. a Ag/AgCl quasi-reference). The anodic peak at þ0.20 V was attributed to the oxidation of HCOOH to CO 2 on surface unblocked by CO, whereas the peak at þ0.51 V was ascribed to the oxidation of surface-adsorbed CO (an intermediate product of HCOOH oxidation) and further oxidation of bulk HCOOH. From the onset potential and current density of the electro-oxidation of HCOOH, FePt nanoparticles exhibit excellent electrocatalytic activities as compared to Pt and other metal alloys. EIS measurements were carried out to further examine the reaction kinetics involved in the HCOOH electro-oxidation. The EIS responses were found to be strongly dependent on electrode potentials. At potentials more positive than À0.25 V (vs. Ag/ AgCl), pseudo-inductive behavior was typically observed. At potentials between þ0.3 and þ0.5 V, the impedance response was found to reverse from the first quadrant to the second quadrant; such negative Faradaic impedance was indicative of the presence of an inductive component due to the oxidation of surface-adsorbed CO. The impedance responses returned to normal behavior at more positive potentials (þ0.6 to þ0.9 V). The mechanistic variation was attributed to the formation of different intermediates (CO or oxygen containing species) on the electrode surface in different potential regions. Two equivalent circuits were proposed to model these impedance behaviors

Role transitions at the prosumer level: Spillover effects in the collaborative economy from an interactive marketing perspective

Purpose: The purpose of this study is to examine the process underlying how consumers shift roles from users to suppliers of goods or services in the collaborative economy (CE). It examines quantatively the impact of a series of explanatory variables underlying that switchover process. Design/methodology/approach: This study identifies and tests the key factors that motivate the userprovider transition by introducing the spillover effect from the proenvironmental literature into collaborative practices and using four experimental designs. Considering behavioral characteristics, context, intrinsic variables and socialization, this study provides an in-depth understanding of the process of transition from user to supplier in the CE. Findings: The results suggest the interactive nature of the spillover as peer influence boosts changes in individual motivations, preferences and behaviors. Furthermore, promoting solidarity between members of the CE platform facilitates the transition of participants from users to providers. In addition, the users’ perception of socialization, satisfaction and sense of indebtedness may also play a significant role in the transition. Research limitations/implications: The study highlights the process underlying the switchover from user to provider at the prosumer level. More specifically, this study identifies key variables influencing the intention to switchover in the CE by drawing on the spillover effect from pro-environmental behavior and considering the spillover as an interactive process. Practical implications: Managers who wish to develop collaborative systems must attract a critical mass of providers to ensure the viability of their systems. Instead of recruiting new providers, managers may convert existing users into providers. This study identifies the key variables to modulate to this end. Originality/value: The findings offer important managerial implications and shed new light on the CE literature

Penetration of Endothelial Cell Coated Multicellular Tumor Spheroids by Iron Oxide Nanoparticles

Iron oxide nanoparticles are a useful diagnostic contrast agent and have great potential for therapeutic applications. Multiple emerging diagnostic and therapeutic applications and the numerous versatile parameters of the nanoparticle platform require a robust biological model for characterization and assessment. Here we investigate the use of iron oxide nanoparticles that target tumor vasculature, via the tumstatin peptide, in a novel three-dimensional tissue culture model. The developed tissue culture model more closely mimics the in vivo environment with a leaky endothelium coating around a glioma tumor mass. Tumstatin-iron oxide nanoparticles showed penetration and selective targeting to endothelial cell coating on the tumor in the three-dimensional model, and had approximately 2 times greater uptake in vitro and 2.7 times tumor neo-vascularization inhibition. Tumstatin provides targeting and therapeutic capabilities to the iron oxide nanoparticle diagnostic contrast agent platform. And the novel endothelial cell-coated tumor model provides an in vitro microtissue environment to evaluate nanoparticles without moving into costly and time-consuming animal models

Consumers’ coping strategies when they feel negative emotions in the face of forced deconsumption during the Covid-19 pandemic lockdowns

Introduction: This paper explores consumers’ coping strategies when they feel negative emotions due to forced deconsumption during the Covid-19 pandemic lockdowns. Methods: The tool used for data collection is the questionnaire. It was made using the LimeSurvey software. A total of 621 complete observations were analyzed. Results: The findings demonstrate that anger positively influences the activation of seeking social support, mental disengagement, and confrontive coping strategies. Besides, disappointment activates mental disengagement but only marginally confrontive coping and not behavioral disengagement. Furthermore, regret is positively related to confrontive coping, behavioral disengagement, acceptance, and positive reinterpretation. Finally, worry positively impacts behavioral disengagement, self-control, seeking social support, mental disengagement, and planful problem-solving. Discussion: The study’s originality lies in its investigation of consumers’ coping strategies when experiencing negative emotions due to forced deconsumption in the context of the Covid-19 pandemic