Synthesis of FeOOH scaly hollow tubes based on Cu_(2)O wire templates toward high-efficiency oxygen evolution reaction

For catalytic materials,the characteristics of one-dimension and hollowness are the promotion factors for their full presentation of catalytic activity,and through a template-as sis ted method,both above superiorities can be fused simultaneously.Here,we proposed a novel strategy inspired by Pearson's principle with Cu_(2)O wires as templates,and prepared FeOOH hollow tubes,which covered by FeOOH scales.When applied as oxygen evolution reaction(OER)catalyst,the FeOOH scaly hollow tubes(FeOOH SHTs)showed outstanding catalytic activity with a low overpotential of 245 mV to drive a current density of10 mA·cm^(-2),excellent kinetics manifesting as a low Tafel slope of 46.9 mV·dec^(-1),and robust stability.This work provides a new synthesis strategy for an ideal OER catalyst,FeOOH,with high inherent activity and enhances the feasibility to broaden the design ideas of transition metalbased catalysts.

Anisotropy of two-dimensional ReS_(2)and advances in its device application

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)have attracted growing interest regarding their potential applications in next-generation electronic and optoelectronic devices.Owing to their atomic thickness and tunable bandgap,they exhibit unique mechanical,electrical,and optical properties.As a specific member of the TMDC family,rhenium disulfide(ReS_(2))has stimulated intensive interest due to its anisotropic crystal structure,weak inter-layer coupling,and anisotropic electrical and optical properties.In this review,we summarize the distinct crystal structure and intrinsic anisotropic properties of ReS_(2),followed by an introduction to its synthesis methods.The current applications of ReS_(2)and its heterojunctions are presented based on its anisotropic properties.This review not only provides a timely summary of the current applications of ReS_(2)and its heterojunctions,but also inspires new approaches to develop other innovative devices based on 2D materials with a low lattice symmetry.

Controlled growth of Au/Ni bimetallic nanocrystals with different nanostructures

Bimetallic nanomaterials are of great signifi- cance to both fundamental research and industrial appli- cations. Their physicochemical performances are critically dependent on their architectures and electronic structures. Here, it was reported a controlled synthesis of Au/Ni bimetallic nanocrystals with different nanostructures, i.e., dumbbell, core@shell and alloyed nanostructures in a one- pot synthesis procedure. Detailed structural characteriza- tions were conducted with the combination of transmission electron microscopy （TEM） and X-ray diffraction （XRD）. Even there is a large lattice mismatch between Au and Ni, Au@Ni core@shell nanocrystals are obtained with the seeded growth method. The growth mechanism was deeply investigated. Triphenylphosphine is demonstrated to be an effective capping agent to modify the interfacial energy to form core@shell nanocrystals, and the higher temperature is proved to be a key role in obtaining alloyed nanocrystals.

Morphology-structure diversity of ZnS nanostructures and their optical properties

ZnS nanostructures with different dimensions and structure-related properties were reviewed in this paper. The crystallization of nanostructures from 0D, 1D to 3D, as well as the heterogonous counterparts, was sum- marized in the aspect of zinc blende, wurtzite structure, and their combinations. Furthermore, the structure-related energy bands and the corresponding photoelectric properties of ZnS nanostructures were also focused, in which we made a brief summary of the co-relations between photoluminescence and crystallography, especially the defectrelated luminescence properties of ZnS nanocrystal.

Magnetic properties of α-Fe_2O_3 nanopallets

It is the result of a systemic study about uniform hematite nanopallets with length of about 100 nm, width of about 30 nm, and thickness of less than 10 nm. The sample has superparamagnetic(SPM) properties above the blocking temperature of ～16 K. The temperature dependence of magnetization was well fitted by Bloch T^(3/2) law considering the dipolar interaction of the particles. The field dependence of magnetization was fitted with revised Langevin equation.The magnetization of the weak ferromagnetic(WF) canted spins contributes to the linear portion in the high field region;the surface uncompensated spins and the parasitic ferromagnetic moments due to the canted spins both contribute to the particle moments and the superparamagnetic behavior.

Editorial for rare metals, special issue on nanomaterials and rechargeable battery applications

Energy and environmental problems have raised great concerns in recent years.Increasing demand and consumption on energy cause many environmental problems.Therefore,the significance of renewable energy is increasing steadily.

Correlation between pass-through flux of cobalt target and microstructure and magnetic properties of sputtered thin films

Cobalt thin films were deposited on silicon substrates by magnetron sputtering two commercial cobalt targets with different pass-through fluxes(PTFs).The influences of PTF on the magnetic properties of sputtered thin films were investigated.The results indicate that under the same sputtering conditions,cobalt thin film deposited by Co target with high PTF(84.21%) has lower remanence ratio(0.65),while cobalt thin film prepared by Co target with low PTF(69.13%) has higher remanence ratio(0.87).Through introducing an external magnetic field parallel to the film surface during sputtering processes,both the remanence ratios of cobalt thin films prepared by the two targets can be enhanced to approach 1.High-resolution transmission electron microscopy(HRTEM) images show that in the absence of the external magnetic field during sputtering,cobalt thin film deposited by the target with high PTF is randomly oriented in crystallographic orientations,which is due to that Co atoms have no enough time to migrate and diffuse on substrate and the atomic stacking is disordered.It is worth mentioning that crystallographic orientations of cobalt thin film deposited by target with low PTF are relatively consistent,resulting in relatively higher remanence ratio.In addition,HRTEM analysis indicates that the external magnetic field during sputtering drives the Co grains to arrange in a regular order with(002) orientation,leading to the improvement in remanence ratios.

On the Distributions of Two Classes of Multiple Dependent Aggregate Claims

In this paper we examine two classes of correlated aggregate claims distributions, with univariate claim counts and multivariate claim sizes. Firstly, we extend the results of Hesselager [ASTIN Bulletin, 24： 19-32（1994）] and Wang ＆ Sobrero＇s [ASTIN Bulletin, 24：161-166 （1994）] concerning recursions for compound distributions to a multivariate situation where each claim event generates a random vector. Then we give a multivariate continuous version of recursive algorithm for calculating a family of compound distribution. Especially, to some extent, we obtain a continuous version of the corresponding results in Sundt [ASTIN Bulletin, 29：29-45 （1999）] and Ambagaspitiya [Insurance： Mathematics and Economics, 24：301-308 （1999）]. Finally, we give an example and show how to use the algorithm for aggregate claim distribution of first class to compute recursively the compound distribution.

Risk-minimizing Hedging Strategy for an Equity-indexed Annuity under a Regime Switching Model

The equity-indexed annuity （EIA） contract offers a proportional participation in the performance of a specified equity index, in addition to a guaranteed return on the single premium. How to manage the risk of the EIA is an important issue. This paper considers the hedging of the EIA. We assume that the parameters of the financial model depend on a continuous-time finite-state Markov chain and the Markov chain is observed, that is the Markov regime switching model. The state of the Markov chain can be interpreted as the state of an economy. Under the regime switching model~ we obtain the risk-minimizing hedging strategy for the EIA.

The secondary prevention of hepatitis B virus-associated hepatocellular carcinoma

Primary liver cancer can be classified into three categories according to different pathological types:hepatocellular carcinoma(HCC),intrahepatic cholangiocarcinoma(ICC),and combined HCC-ICC.