Perovskite materials have rapidly emerged as leading candidates for next-generation photovoltaic technologies, driven by their cost-effectiveness, tunable bandgaps, and remarkable power conversion efficiency. Compared with conventional high-performance photovoltaic materials such as crystalline silicon, copper indium gallium selenide, and organic semiconductors, perovskite solar cells (PSCs) offer significant advantages in terms of efficiency, material versatility, and device fabrication. Owing to sustained research efforts, the performance of PSCs has improved dramatically through the development of passivation strategies, material design, and interface engineering. This review provides a comprehensive overview of recent advances in PSCs, with a particular emphasis on the structural features of perovskite materials that underpin their photovoltaic performance. We begin by introducing the unique structural and optoelectronic properties of perovskites, followed by a discussion of their working principles within different solar cell architectures. We then highlight the mechanisms and progress in low-dimensional (LD)/3D perovskite heterostructures, which have played a crucial role in boosting device efficiency and stability. Finally, we address the remaining challenges to hinder large-scale commercialization and propose future research directions aimed at further enhancing device performance and long-term reliability. By integrating structural and technological insights, this review aims to provide researchers with a clear understanding of the evolution of perovskite solar cell technologies and their prospects for practical application.

Mesocrystals were originally described as superstructures composed of nanocrystals with a common crystallographic orientation. This concept has since evolved into a distinct materials science paradigm. With the rapid advancement of ultrathin epitaxial techniques, such as molecular beam epitaxy and nanolithography, various low-dimensional mesoscopic structures can now be fabricated. In recent years, quantum dot superlattices have emerged as a important platforms for studying low-dimensional mesoscopic systems due to the rich quantum phenomena they exhibit. This article reviews various synthesis methods for quantum dot superlattices, including fabrication processes suchas saturated solvent evaporation, ultrasonication, template-assisted assembly, and liquid-liquid interfacial self-assembly. It further describes the characterization techniques and properties of quantum dot superlattices, and conclude with a discussion of their applications in light emission and photoelectric detection.

The river systems in Guangzhou are complex and diverse. Due to rapid urbanization and industrialization process, the water quality problem is becoming increasingly severe, and regular monitoring is urgently needed. Due to variations in weather, time, location and measurement angle, the measured remote sensing reflectance is greatly affected by the bidirectionality of water bodies (BRDF), making it difficult to establish a unified models. Based on the measured hyperspectra and chlorophyll a concentrations obtained simultaneously, this study introduced BRDF to correct the water reflectance in response to the above issues. An empirical algorithm was used to establish an inversion model of water reflectance and chlorophyll a concentration, and the model accuracy before and after correction was compared. The results show that BRDF correction can effectively improve the model inversion accuracy and reduce abnormal data interference. The applicability of this method to measure has been preliminarily verified.

Promoting the inter-regional enterprise relocation to facilitate industrial coordinated industrial development between the Pearl River Delta and the eastern, western, and northern parts of Guangdong, and to build a new development pattern of mutually reinforcing regional economic progress, has long been a key strategic initiative of Guangdong Province. However, in the academic community the characteristics and outcomes of government-driven enterprise relocation remain unexplored at the micro-level of individual firms. This paper utilizes land transaction data to construct an analytical framework of ″enterprise relocation investment-industrial land transactions-local economic growth,″ examining the spatial distribution characteristics and economic effects of inter-regional enterprise relocation. Employing kernel density analysis, this study depicts the spatial patterns of enterprise relocation from a micro perspective. From the fiscal dimension of land revenue, it further applies individual fixed effects models and geographically weighted regression models to investigate the economic impact of enterprise relocation and its policy implications. The findings reveal that: ① Enterprise relocation in Guangdong Province exhibits spatial evolution characterized by intra-urban suburban diffusion and inter-city polar-core diffusion; ② Industrial land induced by enterprise relocation exerts positive effects on local economic development, and its conveyance spatial differentiation demanstrates a gradual increase from the core to periphery; ③ Enterprise relocation is transitioning from a gradient-driven mode to a new polycentric networds pattern. The study indicates that while Guangdong's policice practices on enterprise relocation have achieved certain successes in promoting local economic development, they also pose new challenges for local governments in institutional innovation and reshaping comparative advantages.

Against the backdrop of large-scale development of rooftop photovoltaic (PV) systems at the city level, few studies have comprehensively considered implementation models, carbon reduction potential, economic feasibility, and government policies, thereby hindering the effective implementation of rooftop PV power generation models. This study analyzes the carbon reduction benefits of rooftop PV power generation in Shenzhen under the engineering, procurement, and construction (EPC) model, with the main conclusions as follows: ① The annual power generation of rooftop PV systems in Shenzhen reaches 13.989 billion kWh, achieving an annual carbon reduction of 7.86 million tons and significant pollutant reduction (SO₂: 6,921 t, NO_x: 6,332 t). The unit carbon emission is 27.35 g CO₂-eq/kWh, demonstrating outstanding carbon reduction benefits. ② The project demonstrates sound economic performance, with a net present value (NPV) of 37.523 billion CNY and an internal rate of return (IRR) of 18.82% under the existing subsidy policy, indicating strong investment feasibility. ③ Sensitivity analysis shows that financial subsidies have the greatest impact on IRR, followed by initial investment, while carbon trading and pollutant prices have the weakest influence, indicating that financial subsidies remain a key driver for rooftop PV construction at the current stage. This study provides targeted recommendations for the rooftop PV power generation model in terms of technological R&D, environmental trading market development, and financial subsidy support, which will serve as a reference for both research and practice in urban rooftop PV projects.

As a national strategic infrastructure project, high-speed railway construction has widely adopted the EPC turnkey contracting model. While this model integrates resources and responsibilities across design, procurement, and construction, thereby improving project efficiency, it also introduces a more complex safety risk system. To systematically identify the interrelationships and hierarchical structure of safety risk factors in high-speed railway EPC projects, this study adopts a system analysis framework encompassing “mon, machine, material, method, and environment” to identify 20 key risk factors across five dimensions. Based on expert survey data, the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method is applied to quantify causal relationships among factors, computed their centrality and causality degrees, and identify core risk factors such as support structure defects, chaotic on-site management, and structural calculation errors. Furthermore, the Interpretive Structural Modeling (ISM) approach is employed to construct a multi-level hierarchical structure of risk factors, revealing the transmission path of risks from underlying personnel and management factors to surface technical and environmental factors. The results indicate that factors such as insufficient personnel competence and ineffective safety reviews are fundamental drivers of systemic risks, while technical factors including support structure defects and inaccurate geological survey data function as intermediate factors, and issues such as material defects and improper selection of mechanical equipment act as direct surface factors. Accordingly, targeted strategies are proposed in four aspects: enhancing personnel capabilities, controlling technical risks, improving full-chain collaborative management, and addressing external environmental challenges. This study provides a theoretical basis for achieving “source control and systematic governance” in safety risk management of high-speed railway EPC projects.

Considered herein is the Cauchy problem for a class of fourth-order Schrödinger equations with second-order nonlinear derivative term iu_t-Δ² u+uΔ|u|²+|u|^p-1u=0. We first construct its variational framework and then prove the existence of standing wave solutions in the context of differing power exponent p and spatial dimension N. In addition, we establish the stability of standing wave solutions through the effective combination of concentration-compactness lemmas and some variational techniques and methods.

This paper studies a coupled spin-polarized system with helicity in R³. Through spatial discretization, we establish the global existence of a weak solution for three-dimensional Cauchy problem.

Cluster algebra is an important research object in algebra. Its generators are cluster variables and satisfy some mutation rule. As a commutative subalgebra of the field of rational functions, there have been some results on the research of the rank 2 cluster algebra $\mathcal{A}$(b, c). In particular, for bc≤4, the cluster algebra has both affine and finite types. By introducing Chebyshev polynomial z_n, this paper establishes multiplication formulas for Kronecker type cluster algebra $\mathcal{A}$(2,2) with principal coefficients.