Accelerated Landweber iteration with convex penalty for linear inverse problems in Banach spaces

In recent years, Landweber iteration has been extended to solve linear inverse problems in Banach spaces by incorporating non-smooth convex penalty functionals to capture features of solutions. This method is known to be slowly convergent. However, because it is simple to implement, it still receives a lot of attention. By making use of the subspace optimization technique, we propose an accelerated version of Landweber iteration with non-smooth convex penalty which significantly speeds up the method. Numerical simulations are given to test the efficiency.     

Tailoring A Poly(ether sulfone) Bipolar Membrane: Osmotic-Energy Generator with High Power Density

Osmotic energy, obtained through different concentrations of salt solutions, is recognized as a form of a sustainable energy source. In the past years, membranes derived from asymmetric aromatic compounds have attracted attention because of their low cost and high performance in osmotic energy conversion. The membrane formation process, charging state, functional groups, membrane thickness, and the ion-exchange capacity of the membrane could affect the power generation performance. Among asymmetric membranes, a bipolar membrane could largely promote the ion transport. Here, two polymers with the same poly(ether sulfone) main chain but opposite charges were synthesized to prepare bipolar membranes by a nonsolvent-induced phase separation (NIPS) and spin-coating (SC) method. The maximum power density of the bipolar membrane reaches about 6.2 W m⁻² under a 50-fold salinity gradient, and this result can serve as a reference for the design of bipolar membranes for osmotic energy conversion systems.     

孔洞和孪晶界对银纳米线形变行为联合影响的分子动力学模拟

Based on molecular dynamics simulations, the plastic deformation of silver nanowires under uniaxial tension has been studied systematically. In this paper, the mechanical properties of [111]-oriented twin nanowires with different hole sizes have been studied. The existence of holes has no effect on the elastic deformation stage. The hole on the twin boundary has two main roles in the plastic deformation stage. During the initial stages of plastic deformation, the main function of the hole is to produce new dislocations as dislocation sources at small hole sizes.Upon increasing the hole size, the main effect changes to stop dislocation slip. During the late stages of plastic deformation, the two functions of the hole complement each other, upon increasing the hole size, the function of the hole as dislocation sources becomes obvious, leading to weakening of the plasticity of the nanowires.     

UiO-66-NH2负载铜催化剂的制备及其对醇的催化氧化

通过溶剂热法成功制备了一种基于金属有机骨架(MOF)的复合材料Cu-Cu₂O/UiO-66-NH₂，采用傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)对材料进行全面表征。在空气作氧化剂条件下，以苯甲醇氧化为苯甲醛作为模型反应，系统地考察了溶剂、温度、催化剂各组分用量等因素对催化效果的影响。研究结果表明，该复合催化剂在醇选择性氧化反应中表现出优异的催化性能，60℃下反应5 h便可将苯甲醇定量转化为苯甲醛，并对其他苄基醇、烯丙基醇和杂芳基醇等底物也展现出良好活性。此外，循环利用3次后，该催化剂活性几乎不变，表明其具有良好的稳定性和重复使用性。     

Convergence for a class of non-autonomous Nicholson’s blowflies model with time-varying coefficients and delays

This paper is concerned with a class of the generalized non-autonomous Nicholson’s blowflies model with time-varying coefficients and delays which is defined on the nonnegative function space. Under proper conditions, we employ a novel proof to establish some criteria to ensure that all solutions of this model converge to an equilibrium. Moreover, we give an example to illustrate our main result.     

Polyvinylidene fluoride/polystyrene hybrid fibers with high ionic conductivity and enhanced mechanical strength as lithium-ion battery separators

Journal of Solid State Electrochemistry - Ionic conductivity is an important separator parameter influencing the cycle life and rate capability of lithium-ion batteries (LIBs). To improve the ionic...     

Exponential convergence of an epidemic model with time-varying delays

In this paper the convergence behavior of an epidemic model with time-varying delays are considered. Some sufficient conditions are established to ensure that all solutions of the epidemic model with permitted initial conditions converge exponentially to zero, which are new and complement previously known results.     

A note on iterative roots of PM functions

In this paper we study iterative roots of PM functions, a special class of non-monotone functions. Problem 2 in [W. Zhang, PM functions, their characteristic intervals and iterative roots, Ann. Polon. Math. LXV (1997) 119-128] is solved partly and Theorem 4 in that paper is generalized.     

含季鏻阳离子的[Mo6O19]2-多酸化合物的合成、结构及光催化性能研究

通过使用季鏻盐与钼酸铵在常温条件下合成了含季鏻阳离子的(n-PentylPh₃P)₂[Mo₆O₁₉]多酸化合物,并通过X-射线单晶衍射、红外光谱、紫外光谱、热重分析和电化学对其进行了表征。产物中的季鏻配体上的氢原子通过与多酸阴离子端基氧原子形成氢键而构筑了一维链状结构,并且季鏻配体上的苯环与相邻季鏻配体上的苯环通过π-π作用形成三维层状结构。此外,对该多酸化合物的光催化降解亚甲基蓝的性能进行了研究。     

钯(II)-柠檬黄-离子液体三元络合体系的共振瑞利散射光谱及其分析应用研究

在pH 2.0～6.0的BR缓冲溶液中, Pd(II)与柠檬黄(TTZ)形成的络离子与溴化1-十六烷基-3-甲基咪唑([C₁₆mim]Br)离子液体发生作用形成离子缔合物, 引起溶液共振瑞利散射(RRS)显著增强, 并产生新的RRS光谱, 其最大RRS峰位于458 nm. 在0.043～0.860 μg/mL范围内散射强度(ΔI)与柠檬黄的浓度成正比. 该方法简单灵敏, 对柠檬黄的检出限(3σ/K)为5.5 ng/mL (n＝11). 建立了一种简便、快速测定柠檬黄的新方法, 并成功用于饮料样中柠檬黄含量的测定.