Variational Inclusion Systems in $\mathbb{R}^N$

The authors study the existence of nontrivial solutions to p-Laplacian variational inclusion systems

A simple and effective scheme for data reduction of stress relaxation incorporating physical-aging effects: An analytical and numerical analysis

A simple methodology for obtaining viscoelastic parameters from the stress relaxation tests incorporating physical-aging effects is presented. The method assumes that the experimental data are in the linear viscoelastic domain. Three different mathematical representations of the viscoelastic stress relaxation modulus are analysed and used. Experimental data obtained from literature and simulated data with a random error are used to evaluate the proposed methodology. It is proved that it can capture very well the relaxation modulus of polymers irrespective of the mathematical representation used for the relaxation modulus. Moreover, the methodology proved to be reasonably insensitive to random noise. Extrapolation predictions were also evaluated for the proposed models with very good results.     

Classification of time-of-flight secondary ion mass spectrometry spectra from complex Cu–Fe sulphides by principal component analysis and artificial neural networks

Artificial neural network (ANN) and a hybrid principal component analysis-artificial neural network (PCA-ANN) classifiers have been successfully implemented for classification of static time-of-flight secondary ion mass spectrometry (ToF-SIMS) mass spectra collected from complex Cu–Fe sulphides (chalcopyrite, bornite, chalcocite and pyrite) at different flotation conditions. ANNs are very good pattern classifiers because of: their ability to learn and generalise patterns that are not linearly separable; their fault and noise tolerance capability; and high parallelism. In the first approach, fragments from the whole ToF-SIMS spectrum were used as input to the ANN, the model yielded high overall correct classification rates of 100% for feed samples, 88% for conditioned feed samples and 91% for Eh modified samples. In the second approach, the hybrid pattern classifier PCA-ANN was integrated. PCA is a very effective multivariate data analysis tool applied to enhance species features and reduce data dimensionality. Principal component (PC) scores which accounted for 95% of the raw spectral data variance, were used as input to the ANN, the model yielded high overall correct classification rates of 88% for conditioned feed samples and 95% for Eh modified samples.     

Are the results of customary methods for analyzing dioxin and dioxin-like compound congener profiles court-proof?

The congener profile of samples contaminated with dioxin and dioxin-like compounds allows identifying sources of contamination. This article studies the statistical methods of congener profile analysis reported in the literature with respect to the reliability of obtained results. The performance of customary analysis methods regarding raw data transformation and applied TEF (toxic equivalency factor) values is discussed. In particular, the method of principal component analysis and k-means cluster is taken as an example and examined in detail. Reasons for occurring inconsistencies such as the dependence of results on raw data transformation and the disregard of measurement uncertainty are described, and it is shown that they also explain inconsistencies in other methods of cluster analysis such as hierarchical cluster analysis and neural networks. It is concluded that these methods cannot be employed to reach court-proof decisions, i.e. decisions which meet court evidentiary standards. An alternative approach to analyzing congener profiles based on mathematical statistics is briefly presented, allowing reliable, court-proof decisions.     

氧气在碳化钨负载的铜-金合金单层上吸附与解离的第一性原理研究

采用基于密度泛函理论的第一性原理方法研究了碳化钨负载的铜-金合金单层催化剂对氧气吸附和解离性质的影响.通过比较碳化钨负载的纯金单层与铜掺杂的合金单层的电荷布局,发现掺杂铜可以创造新的活性位点,改变氧气的吸附构型,改善氧气的吸附和解离性质.进一步探究了氧气在Cu₁Au₈/WC(0001),Cu₂Au₇/WC(0001)上的解离过程,发现:氧气在Cu₂Au₇/WC(0001)上解离势垒仅为0.64 eV,远低于在纯金单层上的1.56 eV,表明铜掺杂有效促进了氧气的解离.铜掺杂后的单层结构变化预示了在单层产生了配位效应和局部应力效应.电荷布局和态密度结果表明铜掺杂促进了单层上电荷的重新分布,加强了氧气分子与基底的电荷转移和轨道杂化,从而增强了对氧气的吸附.当前的研究结果阐明了碳化钨负载合金单层对氧气分解的促进作用和机理,为设计更加高效廉价的氧还原反应催化剂奠定理论基础.     

地表反射太阳辐射的参数化计算方法

 从能量守恒定律出发,建立了朗伯地表对下行辐射的反射作用引起天空亮度变化的解析计算模型。利用射线追踪原理,提出了地表与大气之间多次反射作用的理论模型。引入了一个多次散射的影响因子,并对附加的天空亮度进行了修正。利用混合修正的d-Eddington近似和互易性原理计算了大气的透射率、反照率以及半球平均反照率。最后计算了地表反照率分别为0.15,0.25和0.35情形下的天空亮度增量,实验测量数据证实了这些结果。结果表明：当地表的反照率不为0时,存在“临边增亮”效应,并且随着地表反照率的增大,这种效应更加明显。     

Electrochemical Reactors Enable Divergent Site Selectivity in the C−H Carboxylation of N-Heteroarenes

Catalytic and switchable C−H functionalization of N-heteroarenes under easily tunable conditions is a robust but challenging tool for the construction of biologically relevant compounds. Recently, a general electrochemical strategy has been developed for the direct C−H carboxylation of N-heteroarenes with CO₂, and by simply choosing different types of cell setups, carboxylated products are furnished with excellent and tunable site selectivity. This study also paves the way for regulating the reactivity modes in electrochemical synthesis.     

Sabatier Relations in Electrocatalysts Based on High-entropy Alloys with Wide-distributed d-band Centers for Li-O2 Batteries

Li-O₂ battery (LOB) is a promising “beyond Li-ion” technology with ultrahigh theoretical energy density (3457 Wh kg⁻¹), while currently impeded by the sluggish cathodic kinetics of the reversible gas-solid reaction between O₂ and Li₂O₂. Despite many catalysts are developed for accelerating the conversion process, the lack of design guidance for achieving high performance makes catalysts exploring aleatory. The Sabatier principle is an acknowledged theory connecting the scaling relationship with heterogeneous catalytic activity, providing a tradeoff strategy for the topmost performance. Herein, a series of catalysts with wide-distributed d-band centers (i.e., wide range of adsorption strength) are elaborately constructed via high-entropy strategy, enabling an in-depth study of the Sabatier relations in electrocatalysts for LOBs. A volcano-type correlation of d-band center and catalytic activity emerges. Both theoretical and experimental results indicate that a moderate d-band center with appropriate adsorption strength propels the catalysts up to the top. As a demonstration of concept, the LOB using FeCoNiMnPtIr as catalyst provides an exceptional energy conversion efficiency of over 80 %, and works steadily for 2000 h with a high fixed specific capacity of 4000 mAh g⁻¹. This work certifies the applicability of Sabatier principle as a guidance for designing advanced heterogeneous catalysts assembled in LOBs.     

Recent studies on advance spectroscopic techniques for the identification of microorganisms: A review

The continuous development of resistance to antibiotic drugs by microorganisms causes high mortality and morbidity. Pathogens with distinct features and biochemical abilities make them destructive to human health. Therefore, early identification of the pathogen is of substantial importance for quick ailments and healthcare outcomes. Several phenotype methods are used for the identification and resistance determination but most of the conventional procedures are time-consuming, costly, and give qualitative results. Recently, great focus has been made on the utilization of advanced techniques for microbial identification. This review is focused on the research studies performed in the last five years for the identification of microorganisms particularly, bacteria using advanced spectroscopic techniques including mass spectrometry (MS), infrared (IR) spectroscopy, Raman spectroscopy (RS), and nuclear magnetic resonance (NMR) spectroscopy. Among all the techniques, MS techniques, particularly MALDI-TOF/MS have been widely utilized for microbial identification. A total of 44 bacteria i.e., 6 Staphylococcus spp., 3 Enterococcus spp., 6 Bacillus spp., 4 Streptococcus spp., 6 Salmonella spp., and one from each genus including Escherichia, Acinetobacter, Pseudomonas, Proteus, Clostridioides, Candida, Brucella, Burkholderia, Francisella, Yersinia, Moraxella, Vibrio, Shigella, Serratia, Citrobacter, and Haemophilus (spp.) were discussed in the review for their identification using the above-mentioned techniques. Among all the identified microorganisms, 21% of studies have been conducted for the identification of E. coli, 14% for S. aureus followed by 37% for other microorganisms.