Stochastic delay foraging arena predator–prey system with Markov switching

Abstract

In this paper, we introduce white noise, telegraph noise and time delay to the two-dimensional foraging arena population system describing the prey and predator abundance. The aim is to find out how the interactions between white noise, telegraph noise and time delay affect the dynamics of the population system. Firstly, the existence of a global positive solution is verified. Then the long-time properties including the stochastically ultimate boundedness, extinction and some other asymptotic pathwise estimation of this population system are studied. Finally, the main results are illustrated by two examples.     

临近空间单粒子串扰的解析模型

随着尺寸不断缩减, 串扰对单粒子效应的影响越来越重要. 为了量化串扰效应对单粒子瞬态(SET)的影响, 基于SET等效电路和互连线的6 结点模型, 利用所定义的导纳的四种规则, 简化计算, 推导了单粒子串扰(SEC)的解析模型. 通过求导和泰勒公式, 导出了串扰电压峰值的表达式. 仿真结果显示, 该解析模型与SPICE电路的一致性较好, 平均相对误差为2.51%, 最大误差为5.11%.     

Electrochemical properties of rutile TiO2 nanorods as anode material for lithium-ion batteries

In this paper, we synthesized rutile TiO₂ nanorods by hydrolysis of TiCl₄ ethanolic solution in water at 50?°C. Scanning electron microscopy and transmission electron microscopy images show that the as-prepared sample was consisted of nanoflowers of about 500?nm in sizes, and each petal of nanoflowers was assembled by several nanorods. We tested the electrochemical properties of the rutile TiO₂ nanorods as an anode material for lithium-ion batteries. The rutile TiO₂ nanorods exhibited a large initial discharge capacity of 223?mA?h?g^?1, and the stabilized capacity was as high as 170?mA?h?g^?1 after 100 cycles. These improved electrochemical performances may be attributed to the shorter diffusion length for both the electron and Li⁺, and the large electrode?Celectrolyte contact area offered by the nanorods with a large specific surface area, which facilitated the lithium ions insertion and extraction.     

Heterogeneous copper‐catalyzed oxidative coupling of oxime acetates with sodium sulfinates: An efficient and practical synthesis of β‐keto sulfones

An efficient and practical route to β‐keto sulfones has been developed through heterogeneous oxidative coupling of oxime acetates with sodium sulfinates by using an MCM‐41‐supported Schiff base‐pyridine bidentate copper (II) complex [MCM‐41‐Sb,Py‐Cu (OAc)₂] as the catalyst and oxime acetates as an internal oxidant, followed by hydrolysis. The reaction generates a variety of β‐keto sulfones in good to excellent yields. This new heterogeneous copper (II) catalyst can be easily prepared via a simple procedure from readily available and inexpensive reagents and exhibits the same catalytic activity as Cu (OAc)₂. MCM‐41‐Sb,Py‐Cu (OAc)₂ is also easy to recover and is recyclable up to eight times with almost consistent activity.     

Facile preparation of nano-g-C3N4/UiO-66-NH2 composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

In this work,the nano-g-C₃N₄/Ui O-66-NH₂composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C₃N₄/Ui O-66-NH₂composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatogra...     

A supramolecular cadmium(II) complex: (1,10‐phenanthroline)[tris(2‐amino­ethyl)­amine]­cadmium(II) dinitrate hydrate

Colourless prismatic crystals of the title compound, [Cd(tren)(phen)](NO₃)₂·H₂O [phen = 1,10‐phen­an­thro­line, C₁₂H₈N₂; tren = tris(2‐amino­ethyl)­amine, C₆H₁₈N₄], form from an aqueous solution of equivalent amounts of Cd(NO₃)₂, tren and phen. Infinite one‐dimensional polymeric zigzag motifs, constructed via alternating hydrogen‐bonding and π–π interactions, are further mediated by nitrate–amine hydrogen bonds to create three‐dimensional networks.     

Photopolymerization of metal nanoparticles on multiwall carbon nanotubes

A facile method for the functionalization of multiwall carbon nanotubes (MWCNT) by photopolymerization of 5-mercapto-2,2'-bithiophene modified metal (Au or Ag) nanoparticles on the surface of the MWCNT is developed.     

Bottom-contact poly(3,3'-didodecylquaterthiophene) thin-film transistors with gold source-drain electrodes modified by alkanethiol monolayers

A series of alkanethiol monolayers (CH 3(CH 2) n-1 SH, n = 4, 6, 8, 10, 12, 14, 16) were used to modify gold source-drain electrode surfaces for bottom-contact poly(3,3'-didodecylquaterthiophene) (PQT-12) thin-film transistors (TFTs). The device mobilities of TFTs were significantly increased from approximately 0.015 cm (2) V (-1) s (-1) for bare electrode TFTs to a maximum of approximately 0.1 cm (2) V (-1) s (-1) for the n = 8 monolayer devices. The mobilities of devices with alkanethiol-modified Au electrodes varied parabolically with alkyl length with values of 0.06, 0.1, and 0.04 cm (2) V (-1) s (-1) at n = 4, 8, and 16, respectively. Atomic force microscopy investigations reveal that alkanethiol electrode surface modifications promote polycrystalline PQT-12 morphologies at electrode/PQT-12 contacts, which probably increase the density of states of the PQT-12 semiconductor at the interfaces. The contact resistance of TFTs is strongly modulated by the surface modification and strongly varies with the alkanethiol chain length. The surface modifications of electrodes appear to significantly improve the charge injection, with consequent substantial improvement in device performance.     

The critical behavior of {water + AOT + decane} microemulsion with various molar ratios of water to AOT

To examine the critical behavior of the microemulsion, we have determined the coexistence curves for two ternary microemulsion systems of {water + sodium di(2-ethylhexyl) sulfosuccinate (AOT) + n-decane} with the molar ratios ω = (45.2 and 50.0) of water to AOT, respectively, by measuring refractive index at a constant pressure in the critical region. The critical exponent β and the critical amplitude B have been deduced from the coexistence curves. It was found that the values of β for both systems were consistent with the 3D-Ising exponent in a critical region. By increasing ω, i.e. the droplet size, the critical temperature and, to a lesser extent, the critical concentration decrease. The region of coexisting two phases was drastically reduced by an increase in the droplet size.     

An Injectable Integration of Autologous Bioactive Concentrated Growth Factor and Gelatin Methacrylate Hydrogel with Efficient Growth Factor Release and 3D Spatial Structure for Accelerated Wound Healing

Growth factors are essential for wound healing owing to their multiple reparative effects. Concentrated growth factor (CGF) is a third-generation platelet extract containing various endogenous growth factors. Herein, a CGF extract solution is combined with gelatin methacrylate (GM) by physical blending to produce GM@CGF hydrogels for wound repair. The GM@CGF hydrogels show no immune rejection during autologous transplantation. Compared to CGF, GM@CGF hydrogels not only exhibit excellent plasticity and adhesivity but also prevent rapid release and degradation of growth factors. The GM@CGF hydrogels display good injectability, self-healing, swelling, and degradability along with outstanding cytocompatibility, angiogenic functions, chemotactic functions, and cell migration-promoting capabilities in vitro. The GM@CGF hydrogel can release various effective molecules to rapidly initiate wound repair, stimulate the expressions of type I collagen, transform growth factor β1, epidermal growth factor, and vascular endothelial growth factor, promote the production of granulation tissues, vascular regeneration and reconstruction, collagen deposition, and epidermal cell migration, as well as prevent excessive scar formation. In conclusion, the injectable GM@CGF hydrogel can release various growth factors and provide a 3D spatial structure to accelerate wound repair, thereby providing a foundation for the clinical application and translation of CGF.