正则模型类的时态可定义性

正则模型是非正规模态逻辑的模型,通过定义正则模型的不相交并、C2t-互模拟、生成子模型、C2t-超滤扩张等模型上的运算,可以证明一个正则模型类在时态语言中可定义当且仅当它在不相交并、满C2t-互模拟像、C2t-超滤扩张下封闭,并且它的补类在C2t-超滤扩张下封闭.该刻画定理说明了时态语言在正则模型类上的表达力。     

一个面向服务的应用案例研究

本文从一个现有的信息系统出发,通过分析因为业务增长和环境变化而带来的问题,提出需要进行面向服务的改造。根据面向服务系统的基本原则,从请求之问的状态、请求方式、接口的多样性和体系结构等方面阐述了该系统的改造。本文所描述的SOA改造的方法和体系结构设计以及面向服务改造后带来的优点具有普遍的意义。     

Video super-resolution reconstruction using a mobile search strategy and adaptive patch size

In this study, a new video super-resolution (SR) reconstruction approach using a mobile search strategy and adaptive patch size is proposed. Based on the modified nonlocal-means (NLM) SR algorithm, a mobile search strategy for motion estimation and adaptive patch size are proposed to reduce the computational complexity of the proposed approach and improve the visual quality of the final video SR reconstruction results, respectively. Based on the experimental results obtained in this study, the performance (visual quality and PSNR values) of the proposed approach is better than those of three comparison approaches.     

Synthesis and characterization of cobalt–molybdenum bimetallic carbides catalysts

Co₃Mo₃C, Co₆Mo₆C and MCM41-supported Co₃Mo₃C catalyst are prepared by a simple one-step thermal decomposition method without the conventional temperature-programmed carburization. The resultant carbides are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and BET surface area measurements. The as-prepared Co₃Mo₃C/MCM41 catalyst exhibits good performance in both probe reactions of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), which proves the one-step decomposition method to be an effective route for the preparation of bimetallic carbide catalyst.     

空间实体有限元仿真模拟及实时监控

某公路大桥由于预应力损失变大以及长期超载等原因,主桥中跨跨中出现了约22cm的明显下挠,箱梁内侧腹板出现了大量的斜剪裂缝.利用空间实体有限元模型对该桥加固施工过程中进行仿真模拟,弥补梁单元分析模型中空间效应计算方面的不足,并通过对被加固桥梁进行实时、连续的施工监控,消除温度、振动附加应力影响,从而为加固施工提供更为可靠、真实的监控值和实测数据,从中探索施工监测的新方法.     

Improving Out-of-Plane Charge Mobility and Phase Stability of Dion-Jacobson Lead-Free Perovskites via Intercalating π-Conjugated Aromatic Spacers

The layered quasi-2D perovskites are recognized as one of the effective strategies to resolve the big problem of intrinsic phase instability of the perovskites. However, in such configurations, their performance is fundamentally limited due to the correspondingly weakened out-of-plane charge mobility. Herein, the π-conjugated p-phenylenediamine (PPDA) is introduced as organic ligand ions for rationally designing lead-free and tin-based 2D perovskites with the aid of theoretical computation. It is evidenced that both out-of-plane charge transport capacity and stability can be significantly enhanced within as-established quasi-2D Dion-Jacobson (DJ) (PPDA)Cs_n-1Sn_nI_3n+1 perovskites. The obviously increased electrical conductivity and reduced carrier effective masses are attributed to the enhanced interlayer interactions, limited structural distortions of diamine cations, as well as improved orbital coupling between Sn²⁺ and I⁻ ions of (PPDA)Cs_n-1Sn_nI_3n+1 perovskites. Accordingly, by dimension engineering of the inorganic layer (n), the bandgap (E_g) of quasi-2D perovskites can be linearly tailored toward the suitable E_g (1.387 eV) with optimal photoelectric conversion efficiency (PCE) of 18.52%, representing their great potential toward promising applications in advanced solar cells.     

Effects of redundant systems on controlling the disaster spreading in networks

Many systems in our life contain redundant systems. If one system collapses, its redundant system will substitute it to work for a period of time. In our paper, we have specifically studied the effects of redundant systems on controlling the disaster spreading in networks. Based on the network structure, several redundant strategies have been formulated. On the one hand, the effects of the redundant systems designed uniformly have been studied in different types of networks, the result shows that the random network has been improved the best to fight the disaster. On the other hand, the effectiveness of those redundant strategies have been discussed in the scale free network, results show that the strategy based on total degree is the most effective one to control the spreading. All results found in this paper offer promising perspectives to design redundant systems for preventing cascading failures.