A study of the interaction of cationic dyes with gold nanostructures

The interaction of methylene blue and crystal violet dyes with a range of gold nanoparticles (AuNPs), gold nanoclusters and gold/silver nanoclusters is reported

Ultrasonic guided wave monitoring of dendrite formation at electrode–electrolyte interface in aqueous zinc ion batteries

The formation of dendrite affects the cycling life of a battery and lead to malfunctions such as internal short-circuiting and thermal runaway events. However, existing methods to observe dendrite formation, such as X-ray computed tomography and scanning electron microscopy are either prohibitively complicated or unsuitable for long-term, in-situ monitoring. In this study we present a method which uses the fundamental shear-horizontal mode (SH0*) guided ultrasonic waves to independently monitor the status of the electrodes in a symmetric aqueous zinc-ion battery. Experimental measurements show that the velocity and attenuation of the ultrasonic wave on the opposing electrodes vary in the opposite senses during the cycling. While the velocity and attenuation changes can be partially reversed, a monotonic drift can also be observed with increasing number of cycles. Coupled with optical microscopy, the partially reversible oscillations can be associated with zinc stripping/plating. The irreversible drifting can be associated with the formation of ‘dead’ zinc dendrite. The technique shows clear sensitivity to the formation of dendrite, especially in the early stages (∼10 cycles) of charging and discharging processes. This work should inspire future research to enable quantitative assessment of the technique sensitivity and to improve its resolution

Spin-dependent electrical transport in ion-beam sputter deposited Fe-Cr multilayers

The temperature dependence of the electrical resistivity and magnetoresistance of Xe-ion beam sputtered Fe-Cr multilayers has been investigated. The electrical resistivity between 5 and 300 K in the fully ferromagnetic state, obtained by applying a field beyond the saturation field (H_sat) necessary for the antiferromagnetic(AF)-ferromagnetic(FM) field-induced transition, shows evidence of spin-disorder resistivity as in crystalline Fe and an s-d scattering contribution (as in 3d metals and alloys). The sublattice magnetization m(T) in these multilayers has been calculated in terms of the planar and interlayer exchange energies. The additional spin-dependent scattering \Delta \rho (T) = \rho(T,H=0)_AF - \rho(T,H=H_sat)_FM in the AF state over a wide range of temperature is found to be proportional to the sublattice magnetization, both \Delta \rho(T) and m(T) reducing along with the antiferromagnetic fraction. At intermediate fields, the spin-dependent part of the electrical resistivity (\rho_s (T)) fits well to the power law \rho_s (T) = b - cT^\alpha where c is a constant and b and \alpha are functions of H. At low fields \alpha \approx 2 and the intercept b decreases with H much the same way as the decrease of \Delta \rho (T) with T. A phase diagram (T vs. H_sat) is obtained for the field- induced AF to FM transition. Comparisons are made between the present investigation and similar studies using dc magnetron sputtered and molecular beam epitaxy (MBE) grown Fe-Cr multilayers.Comment: 8 pages, 10 figures, to appear in Phys. Rev.

The Anatomy of Sartorius Muscle and its Implications for Sarcoma Radiotherapy

Purpose: Controversy exists as to whether sartorius muscle is completely invested in fascia. If it is, then direct tumour involvement from soft tissue sarcoma of the anterior thigh would be unlikely and would justify omitting sartorius from the radiotherapy volume

Negative Domain Wall Contribution to the Resistivity of Microfabricated Fe Wires

The effect of domain walls on electron transport has been investigated in microfabricated Fe wires (0.65 to 20 $\mu m$ linewidths) with controlled stripe domains. Magnetoresistance (MR) measurements as a function of domain wall density, temperature and the angle of the applied field are used to determine the low field MR contributions due to conventional sources in ferromagnetic materials and that due to the erasure of domain walls. A negative domain wall contribution to the resistivity is found. This result is discussed in light of a recent theoretical study of the effect of domain walls on quantum transport.Comment: 7 pages, 4 postscript figures and 1 jpg image (Fig. 1

Entangling two Bose Einstein condensates in a double cavity system

We propose a scheme to transfer the quantum state of light fields to the collective density excitations of a Bose Einstein condensate (BEC) in a cavity. This scheme allows to entangle two BECs in a double cavity setup by transferring the quantum entanglement of two light fields produced from a nondegenerate parametric amplifier (NOPA) to the collective density excitations of the two BECs. An EPR state of the collective density excitations can be created by a judicious choice of the system parameters.Comment: 3 figure

Rechargeable aqueous Zn-based energy storage devices

Since the emergence of the first electrochemical energy storage (EES) device in 1799, various types of aqueous Zn-based EES devices (AZDs) have been proposed and studied. The benefits of EES devices using Zn anodes and aqueous electrolytes are well established and include competitive electrochemical performance, low-cost, ease of manufacture, good safety, and environmentally benign characters. Over 50 different types of AZDs (the combination of electrodes and configurations) have been invented; some of them have dominated the current primary battery market, while others are considered promising next-generation EES devices. While most of the existing reviews in this area consider the progress of a particular device or single component, this work adopts a holistic perspective to summarize and review all types of key devices and representative AZDs. First, this work will discuss electrochemical charge storage mechanisms and interface properties in AZDs. Next, the classification, challenges, recent progress, and promising strategies of each key component will be provided. Finally, the way in which components can be assembled to meet the requirements of specific scenarios, including high-capacity, (ultra)high-power, or high-energy applications, will be considered. This work does not attempt to introduce all recent progress but only discuss the most representative work with a view to figure out suitable directions for the advancement of this field

An anti-aging polymer electrolyte for flexible rechargeable zinc-ion batteries

An adhesive polymer electrolyte was developed for solid-state zinc-ion batteries. The resistance maintains constant for over 200 hours, much better than that of conventional hydrogel electrolytes

Mo/Fe bimetallic pyrophosphates derived from Prussian blue analogues for rapid electrocatalytic oxygen evolution

Efficient and stable oxygen evolution electrocatalysts are indispensable for industrial applications of water splitting and hydrogen production. Herein, a simple and practical method was applied to fabricate (Mo, Fe)P2O7@NF electrocatalyst by directly growing Mo/Fe bimetallic pyrophosphate derived from Prussian blue analogues on three-dimensional porous current collector. In alkaline media, the developed material possesses good hydrophilic features and exhibits best-in-class oxygen evolution reaction (OER) performances. Surprisingly, the (Mo, Fe)P2O7@NF only requires overpotentials of 250 and 290 mV to deliver 100 and 600 mA cm−2 in 1 mol L−1 KOH, respectively. Furthermore, the (Mo, Fe)P2O7@NF shows outstanding performances in alkaline salty water and 1 mol L−1 high purity KOH. A worthwhile pathway is provided to combine bimetallic pyrophosphate with commercial Ni foam to form robust electrocatalysts for stable electrocatalytic OER, which has a positive impact on both hydrogen energy application and environmental restoration