The challenge of solving the initial value problem for the coupled Lakshmanan-Porsezian- Daniel equations which involves non-zero boundary conditions at infinity is addressed by the development of a suitable inverse scattering transform. Analytical properties of the Jost eigenfunctions are examined, along with the analysis of scattering coefficient characteristics. This analysis not only leads to the derivation of additional auxiliary eigenfunctions but also is necessary for a comprehensive investigation of the fundamental eigenfunctions. Two symmetry conditions are discussed for studying the eigenfunctions and scattering coefficients. These symmetry results are utilized to rigorously define the discrete spectrum and ascertain the corresponding symmetries of scattering datas. The inverse scattering problem is formulated by the Riemann-Hilbert problem. Subsequently, we derive analytical solutions from the coupled Lakshmanan-Porsezian-Daniel equations with a detailed examination of the novel soliton solutions.

Herglotz’s principle is suitable for dealing with nonconservative phenomena. It is an extension of Hamilton’s principle. The generalized Chaplygin canonical equations are derived from Herglotz principle for nonconservative systems with nonholonomic constraints. The variational equation of Hamilton–Herglotz action for generalized Chaplygin systems is derived by using the Chetaev condition of constraints on virtual displacements. From this, two formulas of non-isochronous variation of the action are deduced. The definitions of Herglotz-type Noether symmetric transformation and quasi-symmetric transformation in phase space are given, and the criterion (i.e., generalized Noether identity) is derived by using total variational formula, and the Herglotz-type Noether-conserved quantities are given. Finally, a nonconservative nonholonomic system is investigated, the Herglotz-type generalized Chaplygin equation and generalized Noether identity are set up, and conservation laws are found by using the theorems we obtained, and the validity of the results is verified.

To facilitate the widespread adoption of typical oxygen reduction reaction (ORR) applications such as fuel cells and metal-air batteries, the development of non-precious metal ORR electrocatalysts with high performance, strong stability, and excellent poisoning resistance is urgent and crucial. In this work, we synthesized Fe, N co- doped carbon nanotube networks (Fe-NCNNs) with highly dispersed active sites and high carbon nanotubulation through the pyrolysis of high-surface-energy precursor (Fe-ZIF-8-20/1) prepared via rapid crystallization strategy. X-ray photoelectron spectroscopy (XPS) results indicated that the doping level of nitrogen in Fe-NCNNs was as high as 10.8 at. %, with pyridinic nitrogen and Fe-Nx being the dominant species. As a result of the synergistic effect of highly conductive carbon nanotubes and dense Fe-Nx active sites, Fe-NCNNs exhibited superior ORR activity to commercial Pt/C in both alkaline and acidic electrolytes. Notably, due to the protection of active sites by in-situ encapsulation, the catalyst also performed excellently in terms of durability and poisoning resistance (against methanol and SCN-). This work provides a new approach for the facile preparation of catalysts with high performance, high stability, and high poisoning resistance.

Nodular diaphragm wall (NDW) is a novel foundation type with favorable engineering characteristics. In contrast to traditional diaphragm walls, the vertical bearing capacity of NDW is significantly enhanced by the existence of nodular sections. Currently, the application and research of NDW are limited, and further clarification is needed regarding its deformation properties and failure modes. This study employs particle image velocimetry (PIV) technology to analyze the displacement and failure mechanisms of the foundation under vertical uplift. The findings indicate that positioning end and middle nodular sections extend the influence range to both deep and shallow soil layers, while multiple nodular sections facilitate in mobilizing broader spectrum of soil. The failure pattens of NDW involve interconnected sliding planes, including vertical sliding planes, inverted pyramid-shaped, or tangent curves, and vase-shaped curves (referred to as curve sliding planes). Overall, compared to pile foundations, the failure surfaces of the retaining wall exhibit complexity, influenced by the number and arrangement of sections, with certain sliding plane orientations correlated with the soil's internal friction angle.

A novel and facile method for the synthesis of N-β-CF3 -substituted 2-pyridones via hydroamination of α-(trifluoromethyl)styrenes with 2-pyridones was described. The reaction proceeded smoothly at room temperature, affording a variety of N-(β-trifluoromethyl-β-arylethyl)pyridin-2(1H)-ones in moderate to good yields with excellent N-regioselectivity.

We consider using Fourier coded aperture transform to solve the acquisition and reconstruction problem of three-dimensional (3-D) hyperspectral imaging. In recent years, Coded aperture snapshot spectral imaging (CASSI) system has received increasing attention. However, reconstruction errors are unavoidable due to its ill-posed problems and the number of dispersion channels is limited. The Hadamard transform spectral (HTS) imaging method has no limitation on the number of dispersion channels, but it usually requires a long data acquisition time. By exploring the process of coded spectral imaging, in this paper, we propose Fourier coded aperture transform spectral imaging (FCTS). We compared the performance of HTS and FCTS by theoretical analysis and experiments. The results show that FCTS has better concentrated energy than HTS on natural hyperspectral data. Compared with the Hadamard transform method, the Fourier basis mode has better physical correlation with the natural image, and the reconstruction quality of FCTS is better than that of HTS in the case of under-sampling.

As single-pixel imaging technology is highly sensitive and low-cost, a large number of hyperspectral imaging methods based on single-pixel have been proposed. Although the image of each band can be reconstructed independently, the parameters that need to be computed for reconstructing hyperspectral images will increase in parallel with the number of bands. Therefore, in this paper, we propose a redundant compressed single-pixel hyperspectral imaging system (RCSHI), which takes full advantage of the spectral redundancy of hyperspectral images by jointly reconstructing images from different bands and compressing the spectral dimension of the data. RCSHI reduces the amount of redundant hyperspectral information stacking and the number of parameters that need to be computed to reconstruct hyperspectral images. In addition, we use progressive fusion enhancement to recover the compressed spectral dimension and enhance the spatial dimension of the images. Experimental results show that RCSHI is able to acquire hyperspectral data with high spatial and spectral resolution and performs well on various datasets and actual scenarios, especially at lower compressed sampling rates.

新工程教育改革下的人才培养目标对设计学专业的教育教学提出了新要求,即要以培养具有创新创业能力和综合实践能力的创新型人才为方向.目前我国高等院校的设计学专业教育教学存在教学定式化、产学相脱节、课程体系不完善等问题.针对这些问题,尝试构建设计学专业新工程教育教学体系,包括彰显"全链式"培养特色,构建"跨学科—多体系"的融合式教学模式,制定"串编式"核心课程规划,实施"共享式"实践项目的组织模式以及建立相关教育教学保障机制等,以期为我国设计学专业人才培养、教学内容改革和教学方法改进提供参考.

Novel 3D printed square auxetic tubular lattice (SATL) structures were designed, fabricated and investigated. Their mechanical properties were examined by the finite element method and experiments. The height and wall thickness show different effects on the mechanical properties of SATL structures. Compared with the circular auxetic tubular (CATL) structures, the SATL structure has a lower peak force under axial load. Under lateral load, the SATL structure has higher stiffness and specific energy absorption. Moreover, the auxetic effect of the proposed SATL structure is also obvious under lateral load. Then, numerical investigations of several improved SATL structures were carried out, the results show that the improved square auxetic tubular lattice (ISATL) structures have stronger energy absorption capacity under axial and lateral loads. Due to their unique structural design and excellent mechanical properties, the SATL structures and ISATL structures have great potential for applications in civil engineering, vehicle crashworthiness and protective infrastructure.

A mild and practical Fe-catalyzed hydroxytrifluoromethylation of α-(trifluoromethyl)styrenes with CF3SO2Na in the presence of K2S2O8 and air was developed. The reaction proceeded efficiently at room temperature without β-fluoride elimination and afforded the corresponding α,β-bistrifluoromethyl tertiary alcohols in good to excellent yields.

With the rise of big data and artificial intelligence, intelligent welding systems (IWS) are attracting more and more attention in machinery manufacturing. The work focused on weld reinforcement monitoring in wire arc additive manufacturing (WAAM). To track deposition status, a weld reinforcement monitoring or prediction system based on multi-modality was proposed. It is expected to be used as a functional component in the IWS in the future, helping to monitor deposition quality and detect anomalies. The reasons for adopting multi-modality can be summarized as follows. Firstly, the complex deposition process is hard to characterize with a single sensor. Secondly, equipped with a multi-sensor can reduce the impact of strong arc light or splash on the monitoring system. To fuse the welding information from different sensors, an implicit fusion method based on parameter sharing was adopted. The core of the proposed monitoring system is the neural network model. The input of the model includes two parts: molten pool images and infrared temperature field. Experimental results demonstrated that the model's weld reinforcement prediction error is around 0.05 mm. The study proved the effectiveness of multi-modal information for weld reinforcement monitoring systems.

以在老龄化的背景下,乡村养老政策的出台使乡村养老成为一大趋势.以老年人需求为出发点,探讨老年人的各类需求在乡村康复景观中的行为体现.研究适宜老年人居住的乡村康复景观,满足当代老年人需求,有助于老人的健康,为乡村景观的设计提供参考.通过对案例的研究,分析在乡村康复景观中与老年人需求相契合的设计要素.以河南焦作韩庄村为例,构建相应的设计策略,以指导乡村康复景观的设计.

通过分析新冠疫情对博物馆线下展览的影响,探寻新冠疫情下博物馆的新机遇,发现"云展览"是博物馆数字化发展道路上新的转机.针对"云展览"的发展现状,并结合国内外相关案例,总结了后疫情时代博物馆"云展览"的优势以及现存的问题,最终提出了博物馆"云展览"的未来发展路径:一是加强"云展览"平台建设和顶层规划;二是加大技术支撑,突破互动体验瓶颈;三是吸纳社会力量参与,构建"云展览"体系;四是拓展"云展览"衍生价值,创新博物馆商业模式.

Auxetic metamaterials have attracted increasing attention due to their exceptional mechanical properties. However, the critical parameters of mechanical response and Poisson's ratio would be changed simultaneously when a geometrical parameter is tuned, which is adverse to achieving the quantitative design of energy absorption by tuning a single geometrical parameter. Thus, the methodology based on tuning densification strain is proposed to design auxetic unit cells with tunable stiffness. In this study, the static performance of 2D metallic auxetic metamaterials designed by the variable stiffness factor (VSF) method is examined experimentally and numerically. To further achieve tunable energy absorption under crushing load, the concept of VSF is extended to variable energy factor (VEF). The dynamic response of verified numerical models is investigated subjected to low-, medium-, and high-velocity crushing. Finally, a functionally graded auxetic structure with different design layers is proposed to effectively solve the issues of high stiffness ratio and initial peak force. These results show that the designed structure has the actual VSF and VEF percentages close to the designed value under low- and medium-velocity crushing. The findings from this study are useful for wider applications of auxetics in protective engineering.

Large-size aluminum alloy rings are widely used as connector, transition ring and reinforcing structure in aerospace and other fields. However, the residual stress introduced during the manufacturing process lead to the structural instability and poor mechanical properties of the aluminum alloy rings. In this paper, pulsed electromagnetic force is used to deform the aluminum alloy rings into plastic state and eliminate the residual stress in the workpieces. The residual stress in a large-size aluminum alloy ring with an outer diameter of 720 mm, a wall thickness of 60 mm, and a height of 60 mm was studied in this paper. To meet the demand of high energy input for bulging the alloy ring, an actuator coil with high voltage insulation and tough inner support was optimized designed by finite element software COMSOL Multiphysics. It was found that adding a steel ring with a truncated gap inside the epoxy skeleton can improve the compression strength of the magnet and increase the plastic deformation of the aluminum alloy ring. Besides, simulation results showed that multiple discharges can reduce the discharge voltage, which can effectively increase the service life and safety of the magnet system.

Bismuth-rich oxyhalides (BixOyXz; X = Cl, Br and I) with optimized morphologies and structures have exhibited prominent photocatalytic activity for the removal of some antibacterials. So far, the antibacterials that have been efficiently degraded by BixOyXz, belong to tetracycline, fluoroquinolone, sulfonamide, metronidazole and chloramphenicol. In this review, degradation mechanisms are summarized based on the significant effect of optimized morphologies and adjusted structures on the production and utilization rate of photogenerated carriers. Corresponding improvements of specific surface area, porosity and surface affinity are underlined. Constructions of binary and ternary heterostructures on the basis of 1D, 2D and 3D BixOyXz, nanostructures are highlighted. Beneficial intimate interfaces, surface defects, band structure and facet exposure are emphasized. Expanding target pollutant to other categories of antibacterials and further improving photocatalytic activities of BixOyXz can pave the way for treating real wastewater containing antibacterials residues. In order to assess the practicability of BixOyXz we need to pay great attention to the essentials of antibacterials composition, water matrix, reaction environment and extension of light-response range. Mixture solutions of several antibacterials with the ratio similar to the formulation in practically treating infections might be the preferred target pollutants in future research. We hope this review will be helpful for scientific community to employ BixOyXz photocatalysts with competitive activities for removing antibacterials residues in aqueous environments. (C) 2020 Elsevier B.V. All rights reserved.

通过对国内发展较好的长三角地区文化艺术产业的研究,总结和归纳文化艺术产业发展的可行策略,形成文化艺术产业发展的地域性发展重塑模式.结果 表明,在现有的发展环境中,文化艺术产业发展需要协调和统筹社会各方力量,不仅要站在文化艺术挖掘了解的角度,还要考虑文化发展的政策环境、投资环境、传统文化艺术和当代设计的美学结合以及和高新技术的发展同步;文化艺术产业发展应在全局和宏观的视角上思考和研究.

运用细分后的Kano模型甄别养老机构中老年人对公共空间需求的优先度排序及其影响因素的主次排序.首先通过规范、文献研究与访谈研究获取南京市养老机构中老年群体公共空间需求要素,并将得到的需求项进行层次归属划分.接着测算SI与DI系数量化各项需求对空间满意度的影响,得出公共空间需求优先度排序.最后利用多元线性回归对需求项的影响因素进行分析,探讨"自我"和"家庭"维度下影响因素的主次排序.得出养老机构公共空间的设计应首先满足老年人医疗保健空间层面的需求且空间需求受老年人"自我"维度下失能等级的影响程度最深.通过对需求重要度的排序,可以得出设计的优先满足策略,提升空间的利用效率及老年群体的满意度,为养老机构公共空间的投入侧重点提供理论依据.