Facile synthesis of NiAl layered double hydroxide nanoplates for high-performance asymmetric supercapacitor

Layered double hydroxide (LDH) is a promising electrode material for supercapacitor owing to its versatility in compositions, high theoretical capacitance, environmental benignity, and low cost. However, capacity fading of LDH hinders its application in energy storage. Herein, we develop a facile approach to synthesize NiAl-LDH nanoplates possessing high electrochemical activity and desirable morphology to improve ion diffusion kinetics and reduce charge transfer resistance, leading to enhanced specific capacitance compared to pristine NiAl-LDH. Scanning electron microscopy shows that the LDH nanoplates are as thin as ∼30 nm with a mean lateral dimension of ∼150 nm. The NiAl-LDH nanoplates electrode delivers remarkably high specific capacitance of 1713.2 F g−1 at 1 A g−1 and good cycling ability of 88% capacitance retention over 5000 cycles compared to only 757.1 F g−1 at 1 A g−1 and 76.4% of the pristine NiAl-LDH. An asymmetric supercapacitor (ASC) is assembled using NiAl-LDH nanoplates and graphene as positive and negative electrodes, respectively. The ASC operating at 1.4 V delivers a high specific capacitance of 125 F g−1 at 1 A g−1 with a high energy density of 34.1 Wh kg−1 at a power density of 700 W kg−1 and outstanding cyclic stability (91.8% capacitance retention after 5000 cycles)

High-performance solid-state flexible supercapacitor based on reduced graphene oxide/hierarchical core-shell Ag nanowire@NiAl layered double hydroxide film electrode

All-solid-state flexible supercapacitor (AFSC) is a promising energy storage device due to its high flexibility, security, and environmental friendliness. However, high electrical resistance and low specific capacitance of electrodes limit its application for potential portable electronic devices. In this study, we design a novel hybrid film electrode composed of reduced graphene oxide (rGO)/silver nanowire (Ag NW)@nickel aluminum layered double hydroxide (NiAl LDH; herein, GAL) possessing high electrochemical performance by using hydrothermal and vacuum filtration techniques. The Ag NW@NiAl LDH (AL) composites with hierarchical core-shell structure are utilized to increase electroactive surface area and improve electrical conductivity, while the rGO nanosheets serve as a prominent carbon material with outstanding electrical conductivity and mechanical flexibility. The freestanding GAL electrode shows high specific capacitance of 1148 F g−1 at 1 A g−1 compared with rGO/NiAl LDH (GL) of 765.2 F g−1 at 1 A g−1. Furthermore, the bind-free symmetric AFSC device is successfully prepared using GAL hybrid film as electrodes and PVA-KOH as solid-state gel electrolyte. The GAL//GAL AFSC device delivers a superior specific capacitance of 127.2 F g−1 at 1 A g−1, a high energy density of 35.75 mWh cm−3 at a power density of 1.01 W cm−3, and great cycling ability of 83.2% over 10,000 cycles at 5 A g−1. This study introduces a novel design of flexible electrode structure for advanced energy storage applications

A topological insulator surface under strong Coulomb, magnetic and disorder perturbations

Three dimensional topological insulators embody a newly discovered state of matter characterized by conducting spin-momentum locked surface states that span the bulk band gap as demonstrated via spin-resolved ARPES measurements . This highly unusual surface environment provides a rich ground for the discovery of novel physical phenomena. Here we present the first controlled study of the topological insulator surfaces under strong Coulomb, magnetic and disorder perturbations. We have used interaction of iron, with a large Coulomb state and significant magnetic moment as a probe to \textit{systematically test the robustness} of the topological surface states of the model topological insulator Bi$_2$Se$_3$. We observe that strong perturbation leads to the creation of odd multiples of Dirac fermions and that magnetic interactions break time reversal symmetry in the presence of band hybridization. We also present a theoretical model to account for the altered surface of Bi$_2$Se$_3$. Taken collectively, these results are a critical guide in manipulating topological surfaces for probing fundamental physics or developing device applications.Comment: 14 pages, 4 Figures. arXiv admin note: substantial text overlap with arXiv:1009.621

Modification of existing water turbine system for application at local river

This thesis is about doing analysis and investigations on river flow rate in Malaysian River which focusing at Sungai Pahang. Through this analysis and investigation could obtain the potential of running a Water Turbine System (WTS). The main problem statement is on location limitation to obtain peak flow rate of river to running water turbine systems which is depending on depth and width of the river and also from the velocity of sectional area of river. Other than that, choosing most suitable water turbine system is also one of main criteria to be taken in this research. Water Turbine are one of clean renewable energy sources which holding high percentage of energy resource provider among renewable energy. The analysis and investigation are constrained from data of river volume flow rate which shows there are peaks values of volume flow rate in Pahang River. This thesis will carry on with modeling a WTS that can be recommended to construct in Pahang River. The analysis on flow rate of Pahang River are done by calculating potential Power (W) that could produced based on volume flow rate data that obtain from Department of Irrigation and Drainage of Malaysia. Since water turbine could provide electricity power without affecting pollution to the environment. Water turbines systems also are cheapest resource to be obtain. Final modeling of water turbine system is completed by using SolidWorks

IL-6 facilitates cross-talk between epithelial cells and tumor- associated macrophages in <i>Helicobacter pylori</i>-linked gastric carcinogenesis

Purpose: Helicobacter pylori (H. pylori) is a significant risk factor for development of gastric cancer (GC), one of the deadliest malignancies in the world. However, the mechanism by which H. pylori induces gastric oncogenesis remains unclear. Here, we investigated the function of IL-6 in gastric oncogenesis and macrophage-epithelial cell interactions. Methods: We analyzed publicly available datasets to investigate the expression of IL-6 and infiltration of M2 macrophages in GC tissues, and determine the inter-cellular communication in the context of IL-6. Human gastric epithelial and macrophage cell lines (GES-1 and THP-1-derived macrophages, respectively) were used in mono- and co-culture experiments to investigate autocrine-and paracrine induction of IL-6 expression in response to H. pylori or IL-6 stimulation. Results: We found that IL-6 is highly expressed in GC and modulates survival. M2 macrophage infiltration is predominant in GC and drives an IL-6 mediated communication with gastric epithelium cells. In vitro, IL-6 triggers its own expression in GES-1 and THP-1-derived macrophages cells. In addition, these cell lines are able to upregulate each other's IL-6 levels in an autocrine fashion, which is enhanced by H. pylori stimulation. Conclusion: This study indicates that IL-6 in the tumor microenvironment is essential for intercellular communication. We show that H. pylori enhances an IL-6-driven autocrine and paracrine positive feedback loop between macrophages and gastric epithelial cells, which may contribute to gastric carcinogenesis.</p

Rotational Symmetry Breaking in a Trigonal Superconductor Nb-Doped Bi₂Se₃

The search for unconventional superconductivity has been focused on materials with strong spin-orbit coupling and unique crystal lattices. Doped bismuth selenide (Bi2Se3) is a strong candidate, given the topological insulator nature of the parent compound and its triangular lattice. The coupling between the physical properties in the superconducting state and its underlying crystal symmetry is a crucial test for unconventional superconductivity. In this paper, we report direct evidence that the superconducting magnetic response couples strongly to the underlying trigonal crystal symmetry in the recently discovered superconductor with trigonal crystal structure, niobium (Nb)-doped Bi2Se3. As a result, the in-plane magnetic torque signal vanishes every 60°. More importantly, the superconducting hysteresis loop amplitude is enhanced along one preferred direction, spontaneously breaking the rotational symmetry. This observation indicates the presence of nematic order in the superconducting ground state of Nb-doped Bi2Se3