Strong coupling between lithiation kinetics and mechanical stress determines the fate of nanostructured electrodes

(i) Material processing testing and characterization that includ

A Chemo-Mechanical model of delithiation in high-capacity anode materials

We present a chemo-mechanical model to investigate the delithiation-induced phase transformation, morphological evolution, stress generation, void nucleation, and growth in high-capacity anode materials such as silicon (Si) and germanium (Ge). The model couples lithium (Li) diffusion with large elasto-plastic deformation by solving a set of coupled phase field and mechanical equilibrium equations using the finite element method, which leads to the coevolution of the Li concentration, stress distribution, and morphology of the anode materials during the delithiation process. The model conveniently simulates the phase boundaries, in addition to void nucleation and growth. Our simulations using this model identify a set of key chemo-mechanical parameters controlling the damage evolution and accumulation in the electrodes. As such, the model offers a generic framework for the study of the degradation mechanisms in the high-capacity electrode materials during electrochemical cycling

Molecular origins of the loss of deformability in Plasmodium -falciparum infected erythrocytes: a coarse-grained modeling

Plasmodium falciparum, the most virulent human malaria parasite, invades human erythrocytes, exports proteins to modify erythrocyte membranes, endows erythrocyte with high stiffness and cytoadherence, and subsequently leading to blockage of blood vessels and dysfunction of organs. Despite continuous progress in experimental studies on erythrocyte remodeling triggered by P. falciparum infection, the underlying molecular mechanisms regarding how the microstructural modifications of erythrocyte membrane lead to the impressive loss of deformability remains elusive. Using a coarse-grained erythrocyte membrane model, capable of incorporating molecular level structural modifications caused by P. falciparum, we systematically investigated shear elasticity of the erythrocyte membranes. Our simulation results show that though the spectrin network accounts for the shear modulus of healthy erythrocyte, pure alteration of the spectrin network could not induce remarkable increase in the shear modulus. Instead, knob formation in the bilayer membrane significantly influences erythrocyte membrane via tightening the associations between spectrin network and lipid bilayer, thereby resulting in increased shear modulus and the loss of deformability. Evolution of knob density and size also plays an important role in enhancing the shear modulus. Shear moduli of P. falciparum-infected erythrocyte at different asexual stages obtained from our model are in good agreement with experimental results. Our findings offer molecular insights into the stiffening mechanism of P. falciparum infected erythrocytes

Trusted Third Parties in the Electronic Marketplace: An Evolutionary Game Approach

Using an evolutionary game approach, this paper studies different equilibria in the electronic marketplace, and demonstrates that electronic transaction through a TTP is an evolutionarily stable strategy. According to the evolutionary game analysis, people will gradually adopt this strategy in the electronic marketplace

An Empirical Analysis of Virtual Goods Pricing Strategies in Virtual Worlds

3D Virtual worlds are computer mediated environments intended for the users to inhabit and interact via their representational avatars. Trading virtual goods in 3D virtual worlds plays an important role in realizing the virtual economy. This essay examines the impact of the unique virtual goods permission settings (Copy, Modify, and transfer) on creators’ pricing strategies. We collect data of virtual items from the Second Life marketplace XStreet to explore the factors that affect virtual goods prices. We use ANOVA to test the relationship between each permission and price, and conduct random effects model to investigate how permissions affect price in different categories. Our empirical results show that “Copy” permission, which might be regarded to reduce the profit of the creators, has a positive effect in virtual goods pricing strategies. Virtual items are more likely to be assigned “Copy” which seems to give additional duplicates for free. Furthermore, prices of virtual goods with “Copy” permission are higher than those without, and the more copies a consumer wants, the higher the price difference between the items with “Copy” and those without “Copy” permission. The effects of other issues on virtual goods prices are analyzed and managerial implications are discussed

Variable Nanoparticle-Cell Adhesion Strength Regulates Cellular Uptake

In receptor-mediated endocytosis, cells exercise biochemical control over the mechanics of adhesion to engulf foreign particles, featuring a variable adhesion strength. Here we present a thermodynamic model with which we elucidate that the variable adhesion strength critically governs the cellular uptake, yielding an uptake phase diagram in the space of ligand density and particle size. We identify from the diagram an endocytosed phase with markedly high uptake, encompassed by a lower and an upper phase boundary that are set, respectively, by the enthalpic and entropic limits of the adhesion strength. The phase diagram may provide useful guidance to the rational design of nanoparticle-based therapeutic and diagnostic agents

Solving the Information Overload Problem: The Role of Unconscious Thought in Enhancing Online Purchasing Decisions

The prosperity of online shopping has led e-commerce vendors to provide increasingly rich information to enhance consumers’ shopping experience and satisfaction. However, there is little awareness that consumers cannot tolerate too much information. As human beings have a limited capacity to process information, online shoppers are easily confused when facing rich information, particularly when the information greatly exceeds their processing capacity. In contrast to previous research, which has focused on the formatting of appropriate information or user interfaces to solve the overload problem, this study explored a new solution based on the role of unconscious as opposed to conscious thought. By combining perspectives from the Unconscious Thought Theory.and Information Processing Theory in a unified model, we examined the role of thinking mode in consumers’ decision satisfaction, as well as information processing factors that affect the efficiency of unconscious thought in the presence of rich information. Results show that unconscious thought is an effective way to solve the information overload problem and is thus worthy of special attention in the design of e-commerce web pages. The study also contributes to both unconscious thought theory and information processing theory by exploring the interaction of the quality and quantity of information with thinking mode in affecting the quality of purchasing decisions

One-particle-thick, Solvent-free, Course-grained Model for Biological and Biomimetic Fluid Membranes

Biological membranes are involved in numerous intriguing biophysical and biological cellular phenomena of different length scales, ranging from nanoscale raft formation, vesiculation, to microscale shape transformations. With extended length and time scales as compared to atomistic simulations, solvent-free coarse-grained membrane models have been exploited in mesoscopic membrane simulations. In this study, we present a one-particle-thick fluid membrane model, where each particle represents a cluster of lipid molecules. The model features an anisotropic interparticle pair potential with the interaction strength weighed by the relative particle orientations. With the anisotropic pair potential, particles can robustly self-assemble into fluid membranes with experimentally relevant bending rigidity. Despite its simple mathematical form, the model is highly tunable. Three potential parameters separately and effectively control diffusivity, bending rigidity, and spontaneous curvature of the model membrane. As demonstrated by selected examples, our model can naturally simulate dynamics of phase separation in multicomponent membranes and the topological change of fluid vesicles

Electrochemically driven mechanical energy harvesting

Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress–voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson’s ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition–voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities.National Science Foundation (U.S.) (CBET-1240696)Samsung Scholarship FoundationKwanjeong Educational Foundatio