Valley and pseudospin-valley topologically protected edge states in symmetric pillared phononic crystals

We present a symmetric double-sided pillared phononic crystals (PPnCs) that can emulate both quantum spin Hall effect (QSHE) and quantum valley Hall effect (QVHE) by solely imposing different geometric perturbations. Indeed, the Dirac cones can occur in the low (deep subwavelength) and high frequency regime by judiciously turning the parameters of the attached pillars and even a double Dirac cone can be achieved. We realize the valley-protected, the pseudospin-protected or the pseudospin-valley coupled edge states with the proposed platform. Besides, we show a variety of refraction phenomena (positive, negative and evanescent) of the valley-polarized edge state at the zigzag termination when emulating QVHE. Further, we illustrate the valley-dependent feature of the pseudospin-valley coupled edge state and demonstrate the valley based splitting of the pseudospin-protected edge states in a Y-junction wave guide.Comment: 4 figure

Perfusion imaging INSPIREs precision medicine in stroke

No abstract available

Contact pressure and wear in sheet metal forming - an FEM analysis

Wear is the principal cause of tool failure in most sheet metal forming processes. It is well known that the contact pressure between the blank and the tool has a large influence on the wear of the tool, and hence the tool life. This investigation utilises the finite element method to analyse the contact pressure distribution over the die radius for a particular deep drawing process. Furthermore, the evolution of the predicted contact pressure distribution throughout the entire stroke of the punch is also examined. It was found that the majority of the process shows a steady state pressure distribution, with two characteristic peaks over the die radius, at the beginning and end of the sheet contact area. Interestingly, the initial transient contact pressure response showed extremely high localised peak pressures; more than twice that of the steady state peaks. Results are compared to wear reported in the literature, during similar experimental deep drawing processes. Finally, the significance and effect of the results on wear and wear-testing techniques are discussed.<br /

Web Aesthetics: How Does it Influence the Sales Performance in Online Marketplaces

Web aesthetics is advocated as one of the key factors influencing consumers’ attitude and behavior in the websites they visited. However, its real effects on the sales performance of websites remain largely unknown. This study is one of the first empirical studies to evaluate web aesthetics quantitatively and directly measure its effects on sales performance by using real-life transaction data. In this study, we identify the representative factors of three primary determinants of web aesthetics (unity, complexity, and intensity) in online marketplaces. Drawing on cognitive dissonance and confirmation bias theory, we further investigate how the influence of web aesthetics on sales performance is contingent on different levels of the seller’s reputation. A set of interaction relationships are proposed and will be tested using real-life transaction data collected from Taobao.com (the largest online marketplace in China). Potential theoretical implications are discussed and potential practical implications are offered for practitioners

Creativity under workload pressure and integrative complexity:The double-edged sword of paradoxical leadership

Modern-day organizations often demand creativity, but motivating creativity under unfavorable conditions such as high workload pressure is difficult. Integrating paradox theory and social cognitive theory, we conceptualize creativity as a process that involves tensions among competing goals and demands, and those tensions become salient under high workload pressure. We propose that learning to constructively deal with such salient tensions is important for the development of creativity and that paradoxical leader behavior (PLB) may stimulate creativity by enhancing employees' creative self-efficacy (CSE) in such challenging situations. However, PLB will only promote CSE and employee creativity when employees have a high level of integrative complexity to accept and appreciate the complex and paradoxical behaviors of the leader. Based on data from 252 employee-supervisor dyads, we found that through CSE, PLB was most effective in promoting employee creativity when workload pressure and integrative complexity were both high. However, PLB was less effective for promoting CSE and creativity when workload pressure was low, or when workload pressure was high while integrative complexity was low. Implications and limitations of our research are discussed

A new kind of Lax-Oleinik type operator with parameters for time-periodic positive definite Lagrangian systems

In this paper we introduce a new kind of Lax-Oleinik type operator with parameters associated with positive definite Lagrangian systems for both the time-periodic case and the time-independent case. On one hand, the new family of Lax-Oleinik type operators with an arbitrary $u\in C(M,\mathbb{R}^1)$ as initial condition converges to a backward weak KAM solution in the time-periodic case, while it was shown by Fathi and Mather that there is no such convergence of the Lax-Oleinik semigroup. On the other hand, the new family of Lax-Oleinik type operators with an arbitrary $u\in C(M,\mathbb{R}^1)$ as initial condition converges to a backward weak KAM solution faster than the Lax-Oleinik semigroup in the time-independent case.Comment: We give a new definition of Lax-Oleinik type operator; add some reference

Quenched Chiral Perturbation Theory for Heavy-light Mesons

We formulate quenched chiral perturbation theory for heavy-light mesons coupled to pions, and calculate the one-loop chiral logarithmic corrections to $f_B$, $f_{B_{s}}$, $B_B$ and $B_{B_{s}}$. We also calculate these corrections for ``partially quenched'' theories. In both theories, the chiral logarithms diverge in the chiral limit, indicating that (partially) quenched theories should not be used to study this limit. Comparing the chiral logarithms to those in QCD, we estimate the errors caused by (partial) quenching. By forming suitable ratios, we can reduce the uncertainties in our estimates.Comment: 22 pages, revtex format, 5 Postscript figure