Single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity

Introducing the top partner is a common way to cancel the largest quadratically divergent contribution to the Higgs mass induced by the top quark. In this work, we study single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity(LHT). Since it is well known that polarized beams can enhance the cross section, we analyze the signal via polarized electron beams,and photon beams. we have selected two decay modes for comparison, based on the leptonic or the hadronic decays of the W and Z from the top partner. We then construct a detailed detector simulation, and choose a set of cuts to enhance signal significance. For mode A(B), the capacity for exclusion in this process at s~(1/2)=3TeV is comparable to the current experimental limits with L=1000(500) fb~(-1). If the integrated luminosity can be increased to 3000 fb~(-1), the top partner mass+mTcan be excluded up to 1350(1440) GeV at 2σ level. We also considered the initial state radiation effect, and find that this effect reduces the excluding ability of the eγ collision on the the top partner mass by approximately 10 GeV. Moreover, the ability to exclude the LHT parameter space at eγ collision complements the existing research.     

Fractional Klein-Gordon-Schrödinger equations with Mittag-Leffler memory

The main objective of the present investigation is to find the solution for the fractional model of Klein-Gordon-Schrödinger system with the aid of q-homotopy analysis transform method (q-HATM). The projected solution procedure is an amalgamation of q-HAM with Laplace transform. More preciously, to elucidate the effectiveness of the projected scheme we illustrate the response of the q-HATM results, and the numerical simulation is offered to guarantee the exactness. Further, the physical behaviour has been presented associated with parameters present the method with respect fractional-order. The present study confirms that, the projected solution procedure is highly methodical and accurate to solve and study the behaviours of the system of differential equations with arbitrary order exemplifying the real word problems.     

NiS助催化剂的硫调控光沉积合成及其增强g-C3N4的光催化产氢性能

作为一种非金属聚合半导体,石墨相氮化碳(g-C3N4)具有特殊的能带结构、可见光响应能力以及优良的物理化学性质以及生产成本低等特点,因而已成为目前光催化领域的研究热点.然而,由于g-C3N4被光激发的电子与空穴极易复合,导致g-C3N4材料的光催化性能并不理想.而助剂修饰是实现光生载流子有效分离以提高光催化活性的有效途径.众所周知,贵金属Pt可以作为光催化产氢的反应位点,但高昂的成本限制了它的实际应用.所以,开发高效的非贵金属助剂很有必要.近年来,NiS作为优良的电子助剂在光催化领域受到广泛关注.大量研究表明,NiS可以作为g-C3N4的产氢活性位点用于提高其光催化产氢性能.NiS助剂主要是通过水热、煅烧和液相沉淀的方法修饰在g-C3N4的表面上.相较而言,助剂的光沉积方法具有一些独特的优势,例如节能、环保、简易并且能够实现其原位牢固地沉积在光催化剂的表面.然而g-C3N4光生电子和空穴强还原和氧化能力容易导致像Ni^2+的还原和S^2-的氧化等副反应发生,因此NiS助剂很难光沉积在g-C3N4材料表面.本文采用硫调控的光沉积法成功合成了NiS/g-C3N4光催化材料,该法利用g-C3N4在光照条件下产生的光生电子结合S以及Ni^2+生成NiS,然后原位沉积在g-C3N4表面.由于E0(S/NiS)(0.096 V)比E0(Ni^2+/Ni)(-0.23 V)更正,所以NiS优先原位沉积在g-C3N4表面.因此,硫调控的光沉积法促进了NiS的生成,并抑制了金属Ni等副反应的形成.通过X射线光电子能谱分析NiS/g-C3N4的表面化学态,表明该方法能成功地将NiS修饰在g-C3N4的表面,这也得到透射电镜和高分辨透射电镜结果的证实.光催化产氢的结果表明,NiS/g-C3N4光催化剂实现了良好的光催化性能,其最优产氢速率(244μmol h^?1 g^?1)接近于1 wt%Pt/g-C3N4(316μmol h^?1 g^?1).这是因为硫调控的光沉积法实现NiS助剂在g-C3N4表面的修饰,从而促进光生电子与空穴的有效分离,进而提高光催化制氢效率.此外,在该方法中,NiS的形成通常在g-C3N4光生电子的表面传输位点上,因此也能够使NiS提供更多的活性位点以提高界面产氢催化反应速率.电化学表征结果也进一步证明NiS/g-C3N4光催化剂加快了电子与空穴的分离和转移.更重要的是,这种简易且通用的方法还可以实现CoSx,CuSx,AgSx对g-C3N4的助剂修饰,并且都提高了g-C3N4的光催化产氢性能,表明该方法具有一定的普适性,为高效光催化材料的合成提供了新的思路.     

Strain-dependent electronic and magnetic of Co-doped monolayer of WSe2

We perform first-principles calculation to investigate electronic and magnetic properties of Co-doped WSe₂ monolayer with strains from −10% to 10%. We find that Co can induce magnetic moment about 0.894 μ_B, the Co-doped WSe₂ monolayer is a magnetic semiconductor material without strain. The doped system shows half-metallic properties under tensile strain, and the largest half-metal gap is 0.147 eV at 8% strain. The magnetic moment (0.894 μ_B) increases slightly from 0% to 6%, and jumps into about 3 μ_B at 8% and 10%, which presents high-spin state configurations. When we applied compressive strain, the doped system shows a half-metallic feature at −2% strain, and the magnetic moment jumps into 1.623 μ_B at −4% strain, almost two times as the original moment 0.894 μ_B at 0% strain. The magnetic moment vanishes at −7% strain. The Co-doped WSe₂ can endure strain from −6% to 10%. Strain changes the redistribution of charges and magnetic moment. Our calculation results show that the Co-doped WSe₂ monolayer can transform from magnetic semiconductor to half-metallic material under strain.     

Theoretical investigation on submicron particle penetration through circular tubes inside a porous medium

The analytical infinite series solution of submicron particle transport in a circular tube bounded by a porous wall, such as a pinhole, is determined under the slip velocity boundary condition, and the solution is verified by using the experimental data in the previous studies for the specific cases. The results show that particle penetration rate increases with the increase of the porous parameter, the axial pressure drop, and the pinhole radius, whereas it decreases with increasing the pinhole length. The penetration rate of nano-particles are more sensitive to the variation of these parameters. However, the differences between the penetrations of particles ranging from 0.3 μm to 1 μm are not evident because the diffusion becomes weak gradually in this size range. In addition, a further comparison is performed between the analytical solution and the existing studies, and approximate expressions are presented for accurate calculation of particle penetration rate through pinholes appearing in porous materials including filter devices and masks.     

Molecular engineering of CxNy: Topologies,electronic structures and multidisciplinary applications

As a class of metal-free two-dimensional (2D) semiconductor materials, polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures, availability in abundance and high stability. According to the different ratios of C and N atoms in the framework, a series of C_xN_y materials have been successfully synthesized by virtue of various precursors, which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing. In view of topological structures on their electronic structures and material properties, the as-reported C_xN_y could be generally classified into two main categories with three- or six-bond-extending frameworks. Owing to the effective n→π* transition in most C_xN_y materials, the relative energy level of the lone-pair electrons on N atoms is high, which thus endows the materials with the capability of visible light absorption. Meanwhile, the different repeating units, bridging groups and defect sites of these two kinds of C_xN_y allow them to effectively drive a diverse of promising applications that require specific electronic, interfacial and geometric properties. This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of C_xN_y materials. In the final part, we also discuss the existing challenges of C_xN_y and outlook the prospect possibilities.     

Nitrogen doped porous carbon as excellent dual anodes for Li- and Na-ion batteries

Biomass-derived carbon materials have obtained great attention due to their sustainability,easy availability,low cost and environmentally benign.In this work,bamboo leaves derived nitrogen doped hierarchically porous carbon have been efficiently synthesized via an annealing approach,followed by an etching process in HF solution.Electrochemical measurements demonstrate that the unique porous structure,together with the inherent high nitrogen content,endow the as-derived carbon with excellent lithium/sodium storage performance.The porous carbon annealed at 700℃presents outstanding rate capability and remarkable long-term stability as anodes for both lithium-ion batteries and sodium-ion batteries.The optimized carbon delivers a high discharge capacity of 450 mAh/g after 500 cycles at the current density of 0.2 A/g for LIBs,and a discharge capacity of 180 mAh/g after 300 cycles at the current density of 0.1 A/g for SIBs.     

Exact solutions of the generalized K(m, m) equations

Family of equations, which is the generalization of the K(m, m) equation, is considered. Periodic wave solutions for the family of nonlinear equations are constructed.     

Simultaneous strain and temperature measurement with a single fiber Bragg grating based on the polarization properties analysis

In this paper, a new technique for discrimination of temperature and strain exploiting the polarization properties of a single normal fiber Bragg grating (FBG) is firstly proposed and experimentally demonstrated. The spectral characterization of the differential group delay (DGD) of the FBG is studied. The evolution of the DGD response of the FBG as a function of temperature and strain is analyzed. The numerical simulations and experimental results suggest that implementing two independent measurements of the resonance wavelength shift and the changes of the DGD can discriminate the temperature and strain effects.