ZrO2/ SiO2多层膜的化学法制备研究

 分别以ZrOCl₂·8H₂O 和正硅酸乙酯为原料,采用溶胶-凝胶工艺制备了性能稳定的ZrO₂和SiO₂溶胶。用旋转镀膜法分别在K9玻璃和单晶硅片上制备了ZrO₂/ SiO₂多层膜。采用溶剂替换和紫外光处理等手段,有效地解决了ZrO₂/SiO₂多层膜中膜层开裂和膜间渗透等问题。应用扫描电子显微镜观测了薄膜的表面和剖面微观形貌,并用椭偏仪测得薄膜的厚度和折射率,研究了薄膜厚度、折射率与热处理温度、紫外光处理时间的关系,对所获得薄膜的紫外-可见、红外光谱进行了分析。用输出波长1064nm ,脉宽15ns 的电光调Q光系统产生的强激光进行了单层膜的辐照实验,结果发现溶剂替换后激光损伤阈值有所提高。     

Characterisation of Plasmodium falciparum aspartic protease inhibition by piperidine derivatives

Piperidine derivatives are reported to exhibit a variety of pharmacological activities. In this article, synthesis and aspartic protease inhibitory activity of three nitrophenacyl derivatives of N-methyl-4-hydroxy piperidine are reported. Enzyme assays showed that the attachment of a nitro group in the benzene ring plays an important role in the inhibition of plasmepsin-II of Plasmodium falciparum. The compound 1-methyl-1-(4'-nitrophenacyl)-4-hydroxypiperidinium bromide (3), consisting of a nitro group at the para position, was the most active at the concentration of 1.0?μM. The activity of the compounds was evaluated through the observed orientation and diagrammatic representation of nitrophenacyl derivatives of 4-hydroxy piperidine.     

Finite-difference analysis of natural convection flow of a viscous fluid in a porous channel with constant heat sources

The fully developed natural convection flow of a viscous fluid in a porous channel is modeled and studied numerically. The walls are kept at constant temperatures. The effects of various dimensionless parameters emerging in the model are studied graphically. It has been noted that the velocity and temperature both depend on the heat source and the free convection parameters.     

Numerical Approximations of Impulsive Delay Differential Equations

The article deals with numerical approximations of impulsive delay differential equations with a non-fixed time of impulses. The right-hand side of the approximation is assumed to be Lipschitz with respect to the norm of the measurable functions, which allows us to estimate the distance between functions with different times of jumps. Illustrative examples are provided.     

Asymptotically absorbing nets of positive operators

This paper is devoted to asymptotically absorbing operator nets. The study of such nets has attracted an attention in [19, 20] in connection with the notion of the Lotz ?? R?biger nets on a Banach space which had been studied recently in [4, 8, 9, 18?C20]. In the present paper, we focus mainly on the case of nets of positive linear operators.     

Novel lanthanum sulfide–decorated zirconia nanohybrid for enhanced electrochemical oxygen evolution reaction

Journal of Solid State Electrochemistry - Metal sulfide and oxides have drawn interest as economical substitutes to noble metal catalysts due to their ability for oxygen evolution reaction (OER)...     

带干扰的索赔次数为复合Poisson—Geometric过程的风险模型下的罚金函数

研究了带干扰的索赔次数为复合Poisson—Geometric过程的风险模型,针对此模型,给出了罚金函数满足的积分微分方程,利用DicksonandHipp（2001）中引入的变换方法,得到了罚金函数的拉普拉斯变换的精确表达式．     

Compact-like operators in lattice-normed spaces

A linear operator $T$ between two lattice-normed spaces is said to be $p$-compact if, for any $p$-bounded net $x_{\alpha }$, the net $T{x}_{\alpha }$ has a $p$-convergent subnet. $p$-Compact operators generalize several known classes of operators such as compact, weakly compact, order weakly compact, $AM$-compact operators, etc. Similar to $M$-weakly and $L$-weakly compact operators, we define $p$-$M$-weakly and $p$-$L$-weakly compact operators and study some of their properties. We also study $up$-continuous and $up$-compact operators between lattice-normed vector lattices.     

Neimark–Sacker bifurcation and chaos control in discrete-time predator–prey model with parasites

In this paper, we discuss the qualitative behavior of a four-dimensional discrete-time predator–prey model with parasites. We investigate existence and uniqueness of positive steady state and find parametric conditions for local asymptotic stability of positive equilibrium point of given system. It is also proved that the system undergoes Neimark–Sacker bifurcation (NSB) at positive equilibrium point with the help of an explicit criterion for NSB. The system shows chaotic dynamics at increasing values of bifurcation parameter. Chaos control is also discussed through implementation of hybrid control strategy, which is based on feedback control methodology and parameter perturbation. Finally, numerical simulations are conducted to illustrate theoretical results.