On the Uphill Domination Polynomial of Graphs

A path π = [v1, v2, …, vk] in a graph G = (V, E) is an uphill path if deg(vi) ≤ deg(vi+1) for every 1 ≤ i ≤ k. A subset S ⊆ V(G) is an uphill dominating set if every vertex vi ∈ V(G) lies on an uphill path originating from some vertex in S. The uphill domination number of G is denoted by γup(G) and is the minimum cardinality of the uphill dominating set of G. In this paper, we introduce the uphill domination polynomial of a graph G. The uphill domination polynomial of a graph G of n vertices is the polynomial , where up(G, i) is the number of uphill dominating sets of size i in G, and γup(G) is the uphill domination number of G, we compute the uphill domination polynomial and its roots for some families of standard graphs. Also, UP(G, x) for some graph operations is obtained.

关于Uphill和Downhill悖论的解释

近年来，国际资本流动发生了逆转，由之前的发达国家流向发展中国家转为由发展中国家流向发达国家。资本流动方向与传统的经济学理论相悖，有关悖论的解释成为国际经济学领域一大挑战。本文拟从制度环境、人口结构、资本市场完善程度、外资利用水平、国际金融秩序领域进行悖论解释。

Stress-Induced Uphill Diffusion with Interfacial Contact Loss in Solid-State Electrodes

We simulate the mechanical-chemical coupling during delithiation and relaxation of a cathode in a solid-state lithium-ion battery.Contact loss at the interface between the active particle and the solid electrolyte is considered.Uphill diffusion is observed during delithiation and relaxation.This phenomenon is explained by analyzing the total chemical potential and its two components.Contact loss at the interface greatly influences the stress and stress gradient in the active particle.As delithiation continues,the stress and stress gradient grow considerably,and the mechanical part of the total chemical potential becomes dominant over the chemical part of it.In the latter stage of delithiation,the influence of the incomplete interfacial constraint on the stress becomes dominant,while the effect of the concentration gradient becomes negligible.After relaxation,the concentration and stress gradients increase in a particle with contact loss.The influence of the degree of contact loss on the mechanical-chemical coupling is investigated.The overall tensile stress in the active particle increases with decreasing contact loss,causing a sharp decrease in local concentration.We also check the effect of the elastic modulus of the solid electrolyte on the coupling of the active material.A rigid solid electrolyte with a higher elastic modulus more strongly restricts the active particle,leading to a higher tensile stress,a larger stress gradient,and a greater concentration gradient.

Uphill Battle for Gillard

The new Australian prime minister must make policy adjustments before an electionu Astralia’s rulingparty, the Labor Party, in lateJune installed

近30年中国耕地上山现象及持续利用评估

In recent years, cropland development in high-slope regions in China has alleviated the contradiction between total cropland balance and insufficient development space. However, this change in cropland slope brings risks to sustainable resource utilization. This study explored the slope characteristics of cropland in China from 1990 to 2020 and assessed the gained cropland stability. The results showed that(1) From 1990 to 2020, the lost cropland area was greater than the gained area, and the distribution showed an uphill trend.(2) The areas with a significant upslope change in cropland were mainly concentrated in the southern plain, containing the central grain-producing regions at its core and other well-developed eastern coastal areas.(3) The areas with distinct downslope cropland changes were mainly concentrated in the upper reaches of the Yangtze and Yellow rivers and the ecologically fragile areas of Inner Mongolia and the Loess Plateau.(4) The gained cropland stability was unsatisfactory;about one-third of the gained cropland was unstable, which had the highest abandonment rate within 5 years, and the gained cropland stability decreased with the slope. In addition, this study explored cropland conversion types at different slopes in different regions and discussed the reasons for slope cropland changes and gained cropland instability in different regions. Finally, optimization policies were proposed to protect and control newly gained cropland.

Synergistic and Antisynergistic Intracrystalline Diffusional Influences on Mixture Separations in Fixed-Bed Adsorbers

Separations of mixtures in fixed-bed adsorbers are influenced by factors such as(1)selectivity of adsorption,Sads,(2)diffusional time constants,Đi/rc 2,and(3)diffusion selectivity,Đ1/Đ2.In synergistic separations,intracrystalline diffusion of guest molecules serves to enhance the selectivities dictated by thermodynamics of mixture adsorption.In antisynergistic separations,intracrystalline diffusion serves to reverse the hierarchy of selectivities dictated by adsorption equilibrium.For both scenarios,the productivities of the desired product in fixed-bed operations are crucially dependent on diffusional time constants,Đi/rc 2;these need to be sufficiently low in order for diffusional influences to be effective.Also,the ratioĐ1/Đ2 should be large enough for manifestation of synergistic or antisynergistic influence.Both synergistic and antisynergistic separations have two common,distinguishing characteristics.Firstly,for transient uptake within crystals,the more mobile component attains supraequilibrium loadings during the initial stages of the transience.Such overshoots,signifying uphill diffusion,are engendered by the cross-coefficientsΓij(i≠j)of thermodynamic correction factors.Secondly,the component molar loadings,plotted in composition space,follow serpentine equilibration paths.If cross-coefficients are neglected,no overshoots in the loadings of the more mobile component are experienced,and the component loadings follow monotonous equilibration paths.The important takeaway message is that the modeling of mixture separations in fixed-bed adsorbers requires the use of the Maxwell−Stefan equations describing mixture diffusion employing chemical potential gradients as driving forces.

Phase evolution of binary immiscible Al-Sn film

Binary immiscible Al-Sn alloy is a very important potential anode material for lithium ion batteries.The phase stability and separation process of Al-Sn film,fabricated by magnetron co-sputtering method,was investigated by X-ray diffractometer(XRD),differential scanning calorimetry(DSC) and in situ transmission electron microscopy(TEM) and explained by Miedema theoretical model.Thermodynamic analysis reveals that the asdeposited Al-Sn film will decompose spontaneously into Al-riched areas and Sn-riched areas because of the positive mixing enthalpy.The crystallization process takes place when the Al content in the Al-riched area or Sn content in the Sn-riched area increases.Experimental results show that Al-Sn thin film is composed of an amorphous matrix and well-dispersed composite nanoparticles.Every particle contains an Al-riched area and a Sn-riched area.The Snriched area crystallizes and swallows up the Al-riched area gradually during heating through uphill diffusion of the Sn atoms.Based on the theoretical analysis and experimental results,an empirical model to explain the phase evolution process in the Al-Sn film was proposed.