On the Möbius Function of a Pointed Graded Lattice

In this paper, we compute the Möbius function of pointed integer partition and pointed ordered set partition using topological and analytic methods. We show that the associated order complex is a wedge of spheres and compute the associated reduced homology group for each subposet. In addition, we compute the Möbius function of pointed graded lattice and use our method to compute the Möbius function of pointed direct sum decomposition of vector spaces.     

Atomic orbitals in molecules: general electronegativity and improvement of Mulliken population analysis

An approach of atomic orbitals in molecules (AOIM) has been developed to study the atomic properties in molecules, in which the molecular orbitals are expressed in terms of the optimized minimal atomic orbitals. The atomic electronegativities are calculated using Pauling's electronegativity of free atom and are employed to find the electronegativity equilibrium in molecules and to describe the amphoteric properties of the transition metals from the groups 4 to 10. AOIM can also improve the numerical stability and accuracy of the original Mulliken population analysis.     

A review on use of TRNSYS as simulation tool in performance prediction of desiccant cooling cycle

Journal of Thermal Analysis and Calorimetry - Solid desiccant-assisted cooling and dehumidification systems are becoming very popular nowadays for maintaining the required thermal comfort in...     

一类A(α)稳定的k阶线性k步法公式

本文给出了一类与Gear方法类似的κ阶线性κ步法隐式公式.作者还求出了公式的分数形式的系数,阶数和局部截断误差主项系数,并验证了2-6步公式都具有A(α)稳定的,计算出了它们的幅角α.最后用对比数值实验验证了公式确实是稳定的,并且适合于求解刚性常微分方程.     

Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment

Efficient hydrolysis of cellulose-to-glucose is critically important in producing fuels and chemicals from renewable feedstocks. Cellulose hydrolysis in aqueous media suffers from slow reaction rates because cellulose is a water-insoluble crystalline biopolymer. The high-crystallinity of cellulose fibrils renders the internal surface of cellulose inaccessible to the hydrolyzing enzymes (cellulases) as well as water. Pretreatment methods, which increase the surface area accessible to water and cellulases are vital to improving the hydrolysis kinetics and conversion of cellulose to glucose. In a novel technique, the microcrystalline cellulose was first subjected to an ionic liquid (IL) treatment and then recovered as essentially amorphous or as a mixture of amorphous and partially crystalline cellulose by rapidly quenching the solution with an antisolvent. Because of their extremely low-volatility, ILs are expected to have minimal environmental impact. Two different ILs, 1-n-butyl-3-methylimidazolium chloride (BMIMC1) and 1-allyl-3-methylimidazolium chloride (AMIMC1) were investigated. Hydrolysis kinetics of the IL-treated cellulose is significantly enhanced. With appropriate selection of IL treatment conditions and enzymes, the initial hydrolysis rates for IL-treated cellulose were up to 90 times greater than those of untreated cellulose. We infer that this drastic improvement in the "overall hydrolysis rates" with IL-treated cellulose is mainly because of a significant enhancement in the kinetics of the "primary hydrolysis step" (conversion of solid cellulose to soluble oligomers), which is the rate-limiting step for untreated cellulose. Thus, with IL-treated cellulose, primary hydrolysis rates increase and become comparable with the rates of inherently faster "secondary hydrolysis" (conversion of soluble oligomers to glucose).     

Stability and bifurcation analysis in the delay-coupled nonlinear oscillators

This paper investigates the dynamical behavior of two oscillators with nonlinearity terms, which are coupled with finite delay parameters. Each oscillator is a general class of second-order nonlinear delay-differential equations. The system of delay differential equations is analyzed by reducing the delay equations to a system of ordinary differential equations on a finite-dimensional center manifold, the corresponding to an infinite-dimensional phase space. In addition, the characteristic equation for the linear stability of the trivial equilibrium is completely analyzed and the stability region is illustrated in the parameters space. Our analysis reveals necessary coefficients of the reduced vector field on the center manifold for studying the bifurcations of the trivial equilibrium such as transcritical, pitchfork, and Hopf bifurcation. Finally, we consider the delay-coupled van der Pol equations.     

Edge-plane-rich nitrogen-doped carbon nanoneedles and efficient metal-free electrocatalysts

CNN news: N-doped carbon nanoneedles (CNNs) are synthesized by self-assembling core-shell nanostructures and nanoreactors around cellulose nanoneedles, and subsequent graphitization. The resulting graphitic nanoneedles (see picture) have well-organized graphitic multi-layers and large proportions of N-doped edge planes. The materials serve as efficient metal-free electrocatalysts for hydrazine oxidation.