Xi'an Shiyou University

Single-atom photocatalysts have shown their compelling potential and arguably become the most active research direction in photocatalysis due to their fascinating strengths in enhancing light-harvesting, charge transfer dynamics, and surface reactions of a photocatalytic system. While numerous comprehensions about the single-atom photocatalysts have recently been amassed, advanced characterization techniques and vital theoretical studies are strengthening our understanding on these fascinating materials, allowing us to forecast their working mechanisms and applications in photocatalysis. In this review, we begin by describing the general background and definition of the single-atom photocatalysts. A brief discussion of the metal-support interactions on the single-atom photocatalysts is then provided. Thereafter, the current available characterization techniques for single-atom photocatalysts are summarized. After having some fundamental understanding on the single-atom photocatalysts, their advantages and applications in photocatalysis are discussed. Finally, we end this review with a look into the remaining challenges and future perspectives of single-atom photocatalysts. We anticipate that this review will provide some inspiration for the future discovery of the single-atom photocatalysts, manifestly stimulating the development in this emerging research area.

This tutorial review elucidates how to design catalytically active sites for efficient and highly selective photocatalytic reduction of CO₂ by learning from conventional CO₂ hydrogenation and syngas conversion.

The key drivers of 6G result not only from the challenges and performance limits that 5G presents but also from the technology-driven paradigm shift and the continuous evolution of wireless networks. Intelligent driving and industry revolutions create core requirements for 6G that will lead to service classes of ubiquitous mobile ultrabroadband (uMUB), ultrahighspeed-with-low-latency communications (uHSLLC), and ultrahigh data density (uHDD).

Abstract Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.

Abstract With the serious impact of fossil fuels on the environment and the rapid development of the global economy, the development of clean and usable energy storage devices has become one of the most important themes of sustainable development in the world today. Supercapacitors are a new type of green energy storage device, with high power density, long cycle life, wide temperature range, and both economic and environmental advantages. In many industries, they have enormous application prospects. Electrode materials are an important factor affecting the performance of supercapacitors. MnO 2 ‐based materials are widely investigated for supercapacitors because of their high theoretical capacitance, good chemical stability, low cost, and environmental friendliness. To achieve high specific capacitance and high rate capability, the current best solution is to use MnO 2 and carbon composite materials. Herein, MnO 2 –carbon composite as supercapacitor electrode materials is reviewed including the synthesis method and research status in recent years. Finally, the challenges and future development directions of an MnO 2 –carbon based supercapacitor are summarized.

The purpose of this article was to quantitatively investigate the pore structure and fractal characteristics of different lithofacies in the upper Permian Dalong Formation marine shale. Shale samples in this study were collected from well GD1 in the Lower Yangtze region for mineral composition, X-ray diffraction (XRD), and nitrogen adsorption–desorption analysis, as well as broad-ion beam scanning electron microscopy (BIB-SEM) observation. Experimental results showed that the TOC (total organic carbon) content and vitrinite reflectance (Ro) of the investigated shale samples were in the ranges 1.18–6.45% and 1.15–1.29%, respectively, showing that the Dalong Formation shale was in the mature stage. XRD results showed that the Dalong Formation shale was dominated by quartz ranging from 38.4% to 54.3%, followed by clay minerals in the range 31.7–37.5%, along with carbonate minerals (calcite and dolomite), with an average value of 9.6%. Based on the mineral compositions of the studied samples, the Dalong Formation shale can be divided into two types of lithofacies, namely siliceous shale facies and clay–siliceous mixed shale facies. In siliceous shale facies, which were mainly composed of organic pores, the surface area (SA) and pore volume (PV) were in the range of 5.20–10.91 m2/g and 0.035–0.046 cm3/g, respectively. Meanwhile, the pore size distribution (PSD) and fractal dimensions were in the range 14.2–26.1 nm and 2.511–2.609, respectively. I/S (illite-smectite mixed clay) was positively correlated with SA, PV, and fractal dimensions, while illite had a negative relationship with SA, PV, and fractal dimensions. I/S had a strong catalytic effect on organic matter for hydrocarbon generation, which was beneficial to the development of organic micropores, so I/S was conducive to pore structure complexity and the increase in SA and PV, while illite easily filled organic pores, which was not beneficial to the improvement of pore space. In clay–siliceous mixed shale facies, which mainly develop inorganic pores such as intergranular pores, SA and PV were in the range of 6.71–11.38 m2/g and 0.030–0.041 cm3/g, respectively. Meanwhile, PSD and fractal dimensions were in the range of 14.3–18.9 nm and 2.563–2.619, respectively. Quartz and I/S showed weak positive correlations with SA, PV, and fractal dimensions. The various compact modes between quartz particles and the disorder of I/S were conducive to the complexity of pore structure and the improvement of SA and PV. The research findings can provide a reference for the optimization and evaluation of shale gas favorable area of the Lower Yangtze Platform.

The big success in marine shale gas exploration and production made China the third country worldwide to commercialize shale gas development. However, the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation in and around the Sichuan Basin are currently the only targets that have realized shale gas industrial development. Great challenges are emerging since tremendous shale gas resources of marine facies, continental facies, and transitional facies that are trapped in new areas and multiple other formations are yet to be successfully developed. Thus, we find it a great necessity to provide suggestions on shale gas exploration and development in China, which hopefully can be helpful for global shale gas exploitation. To meet this goal, this work provides a critical review on the history and current status of China’s shale gas exploration and development and summarizes key practical experiences. In the light of characteristic analysis of typical industrial gas fields and wells, research status, problems and challenges, along with suggestions on pivotal scientific issues are addressed including the development of organic-rich shales, reservoir types and characteristics, shale gas content, and the main controlling factors on shale gas enrichment. Further, future directions of shale gas exploration and development are nailed down, incorporating three levels: areas to improve development technology, areas to seek exploration breakthrough, and areas to conduct preliminary studies. The normal-pressure and deep shale gas retained in the Wufeng and Longmaxi Formations in and around the Sichuan Basin are the first level, which are the most realistic resources that can be commercially developed. For the normal-pressure shale gas, detailed research on the sweet spot selection, drilling–encounter ratio enhancement, and cost minimization by advanced technologies are most imperative; for the deep shale gas, state-of-the-art technology to maximize the stimulated reservoir volume of lateral wells is the key. Gas resources in other shale formations in the Sichuan Basin and its periphery such as the Cambrian marine shales, Permian transitional shales, and Jurassic continental shales are the second level, which have the greatest prospective to claim exploration breakthroughs, while shale gas resources in other basins or regions still demand grand scientific and technological tasks for exploration and development preparation. All in all, as a country with diverse shale gas types and such intricate geological and surface conditions, the summary of China’s shale gas exploration and development practices is of vital significance that will not only shed light on China’s shale gas development directions but also provide references for the shale gas industry in other countries and regions.

A supercapacitor is a potential electrochemical energy storage device with high-power density (PD) for driving flexible, smart, electronic devices. In particular, flexible supercapacitors (FSCs) have reliable mechanical and electrochemical properties and have become an important part of wearable, smart, electronic devices. It is noteworthy that the flexible electrode, electrolyte, separator and current collector all play key roles in overall FSCs. In this review, the unique mechanical properties, structural designs and fabrication methods of each flexible component are systematically classified, summarized and discussed based on the recent progress of FSCs. Further, the practical applications of FSCs are delineated, and the opportunities and challenges of FSCs in wearable technologies are proposed. The development of high-performance FSCs will greatly promote electricity storage toward more practical and widely varying fields. However, with the development of portable equipment, simple FSCs cannot satisfy the needs of integrated and intelligent flexible wearable devices for long durations. It is anticipated that the combining an FSC and a flexible power source such as flexible solar cells is an effective strategy to solve this problem. This review also includes some discussions of flexible self-powered devices.

In the past decade, metal halide perovskite (HP) has become a superstar semiconductor material due to its great application potential in the photovoltaic and photoelectric fields. In fact, HP initially attracted worldwide attention because of its excellent photovoltaic efficiency. However, HP and its derivatives also show great promise in X-ray detection due to their strong X-ray absorption, high bulk resistivity, suitable optical bandgap, and compatibility with integrated circuits. In this review, the basic working principles and modes of both the direct-type and the indirect-type X-ray detectors are first summarized before discussing the applicability of HP for these two types of detection based on the pros and cons of different perovskites. Furthermore, the authors expand their view to different preparation methods developed for HP including single crystals and polycrystalline materials. Upon systematically analyzing their potential for X-ray detection and photoelectronic characteristics on the basis of different structures and dimensions (0D, 2D, and 3D), recent progress of HPs (mainly polycrystalline) applied to flexible X-ray detection are reviewed, and their practicability and feasibility are discussed. Finally, by reviewing the current research on HP-based X-ray detection, the challenges in this field are identified, and the main directions and prospects of future research are suggested.

The development of Artificial Neural Networks (ANNs) has achieved a lot of fruitful results so far, and we know that activation function is one of the principal factors which will affect the performance of the networks. In this work, the role of many different types of activation functions, as well as their respective advantages and disadvantages and applicable fields are discussed, so people can choose the appropriate activation functions to get the superior performance of ANNs.

Oily sludge is a kind of solid emulsified waste produced by the petroleum industry. It is generally composed of water, crude oil, and solid particulate matter. Because it contains large amounts of cycloalkanes, benzene series, polycyclic aromatic hydrocarbons, and other toxic and harmful substances, it poses a substantial threat to human health and the surrounding environment; therefore, it must be treated to reduce its toxicity. However, a large component of oily sludge is crude oil, which has great recycling value. Therefore, various crude oil recovery technologies, such as solvent extraction, pyrolysis, centrifugation, ultrasonic treatment, electronal treatment, flotation, supercritical treatment, and combined processes, have been developed for the treatment of oily sludge. The main purpose of this review is to discuss the development of these recycling technologies and to summarize and compare their advantages, disadvantages, and mechanisms of action. On this basis, the future development direction of recycling technology is prospected.

Last several years, industrial and information technology field have undergone profound changes, entering "Industry 4.0" era. Industry4.0, as a representative of the future of the Fourth Industrial Revolution, evolved from embedded system to the Cyber Physical System (CPS). Manufacturing will be via the Internet, to achieve Internal and external network integration, toward the intelligent direction. This paper introduces the development of Industry 4.0, and the Cyber Physical System is introduced with the example of the Wise Information Technology of 120 (WIT120), then the application of Industry 4.0 in intelligent manufacturing is put forward through the digital factory to the intelligent factory. Finally, the future development direction of Industry 4.0 is analyzed, which provides reference for its application in intelligent manufacturing.

Summary Hydraulic fracturing is an indispensable technology in developing tight oil and gas resources. However, the development of tight oil and gas is not consistently satisfactory. Further understanding of hydraulic fracturing of tight sandstone is required, which increases the production of tight oil and gas reservoirs, particularly in China. Currently, there are a few true triaxial hydraulic fracturing physical simulations of large tight sandstone outcrops. To weaken the boundary effect, this study performed simulations using large tight sandstone outcrops (500 × 500 × 500 mm and 500 × 500 × 800 mm) in the Shahezi Formation (Fm.), Jilin Province, China. The effect of natural fracture (NF) development degree, in-situ stress conditions, fracturing treatment parameters, and temporary plugging on fracture propagation were investigated. Furthermore, fracture propagation was investigated based on post-fracturing fine reconstruction, high-energy computed tomography (CT) scan, acoustic emission monitoring (AEM), and analysis of a fracturing pressure curve. Finally, suggestions on fracturing treatment were proposed. The results show that the NF is a key factor in determining the hydraulic fracture (HF) morphology in the tight sandstone reservoir. Further, the number, approaching angle, and cementation strength of the preexisting NF affect the HF propagation path; these are the key factors for forming complex fractures. In the tight sandstone reservoir with well-developed NFs, the fracture morphology is dominated by the NF under horizontal differential stress ≤ 9 MPa. A single fracture is more likely to occur under horizontal differential stress ≥ 12 MPa, which is less affected by the NF. In the fracturing at variable injection rates, a low rate facilitates fluid penetration into the NF, while a high rate facilitates deep HF propagation. A low-viscosity fracturing fluid at a high rate facilitates further propagation of the temporary plugging agent (TPA), thus achieving deep temporary plugging and fracture diversion. A high-viscosity fluid does not facilitate accumulation and plugging of particulate TPA. Higher horizontal differential stress leads to a smaller diversion radius of new HF, which is closer to the original HF, leading to poorer stimulation effect. The results provide a reference for the fracturing design of the tight sandstone.

BACKGROUND: Endometrial cancer is one of the most common female reproductive system tumors. Ninjurin2 (NINJ2) is a new adhesion factor. As a vascular susceptibility gene, it is highly expressed in other cancers and promotes the growth of cancer cells. We conducted an association analysis between NINJ2 gene polymorphism and endometrial cancer risk. METHODS: Five SNPs rs118050317, rs75750647, rs7307242, rs10849390 and rs11610368 of NINJ2 gene were genotyped in 351 endometrial cancer patients and 344 healthy controls. The clinical index difference between cases and controls were tested by one-way analysis of variance. The allele and genotype frequency of cases and controls were been compared by Chi square test. The odds ratios (OR) with 95% confidence interval (95% CI) were examined by logistic regression analysis. RESULTS: The SNP rs118050317 mutant allele C and homozygote CC genotype were significant increased the endometrial cancer risk (OR 1.46, 95% CI 1.04-2.06, p = 0.028; OR 8.43, 95% CI 1.05-67.89, p = 0.045). In the clinical index analysis, there were significant higher quantities of CEA, CA125 and AFP in cases serum than controls. CONCLUSION: The NINJ2 gene polymorphism loci rs118050317 mutant allele C was associated with an increased risk of endometrial cancer. CEA, CA125 and AFP quantities were significant higher in endometrial cancer patients.

Abstract Structural reconstruction is a process commonly observed for Cu‐based catalysts in electrochemical CO 2 reduction. The Cu‐based precatalysts with structural complexity often undergo sophisticated structural reconstruction processes, which may offer opportunities for enhancing the electrosynthesis of multicarbon products (C 2+ products) but remain largely uncertain due to various new structural features possibly arising during the processes. In this work, the Cu 2 O superparticles with an assembly structure are demonstrated to undergo complicated structure evolution under electrochemical reduction condition, enabling highly selective CO 2 ‐to‐C 2+ products conversion in electrocatalysis. As revealed by electron microscopic characterization together with in situ X‐ray absorption spectroscopy and Raman spectroscopy, the building blocks inside the superparticle fuse to generate numerous grain boundaries while those in the outer shell detach to form nanogap structures that can efficiently confine OH − to induce high local pH. Such a combination of unique structural features with local reaction environment offers two important factors for facilitating C−C coupling. Consequently, the Cu 2 O superparticle‐derived catalyst achieves high faradaic efficiencies of 53.2% for C 2 H 4 and 74.2% for C 2+ products, surpassing the performance of geometrically simpler Cu 2 O cube‐derived catalyst and most reported Cu electrocatalysts under comparable conditions. This work provides insights for rationally designing highly selective CO 2 reduction electrocatalysts by controlling structural reconstruction.

Image segmentation is a classic subject in the field of image processing and also is a hotspot and focus of image processing techniques. With the improvement of computer processing capabilities and the increased application of color image, the color image segmentation are more and more concerned by the researchers. Color image segmentation methods can be seen as an extension of the gray image segmentation method in the color images, but many of the original gray image segmentation methods can not be directly applied to color images. This requires to improve the method of original gray image segmentation method according to the color image which have the feature of rich information or research a new image segmentation method it specially used in color image segmentation. This article proposes a color image segmentation method of automatic seed region growing on basis of the region with the combination of the watershed algorithm with seed region growing algorithm which based on the traditional seed region growing algorithm.

Abstract 2D layered metallic graphite composites are promising electromagnetic wave absorption materials (EWAMs) for their combined properties of abundant interlayer free spaces, rich metallic polarized sites, and high conductivity, but the controllable synthesis remains rather challenging. Herein, a dual‐step redox engineering strategy is developed by employing cobalt boron imidazolate framework (Co‐BIF) to construct 2D CoNi‐alloy embedded B, N‐doped carbon layers (2D‐CNC) as a promising EWAM. In the first step, a chemical etching oxidation process on Co‐BIF is used to obtain an optimized 2D‐CoNi‐layered double hydroxide (2D‐CoNi‐LDH) intermediate and in the second, high‐temperature calcination reduction is implemented to modify graphitization of the degree of the 2D‐CNC. The obtained sample delivers superior reflection loss (RL min ) of −60.1 dB and wide effective absorption bandwidth (EAB) of 6.24 GHz. The synergy mechanisms of interfacial/dipole polarization and magnetic coupling are in‐depth evidenced by the hologram and Lorentz electron microscopy, revealing its significant contribution on multireflection and impedance matching. Further theoretical evaluation by COMSOL simulation in different fields based on the dynamic loss process toward the test ring reveals the in situ EW attenuation process. This work presents a strategy to develop multifunctional light‐weight infrared stealthy aerogel with superior pressure‐resistant, anti‐corrosion, and heat‐insulating properties for future applications.

Graphitic carbon nitride (g-C3N4), with facile synthesis, unique structure, high stability, and low cost, has been the hotspot in the field of photocatalysis. However, the photocatalytic performance of g-C3N4 is still unsatisfactory due to insufficient capture of visible light, low surface area, poor electronic conductivity, and fast recombination of photogenerated electron-hole pairs. Thus, different modification strategies have been developed to improve its performance. In this review, the properties and preparation methods of g-C3N4 are systematically introduced, and various modification approaches, including morphology control, elemental doping, heterojunction construction, and modification with nanomaterials, are discussed. Moreover, photocatalytic applications in energy and environmental sustainability are summarized, such as hydrogen generation, CO2 reduction, and degradation of contaminants in recent years. Finally, concluding remarks and perspectives on the challenges, and suggestions for exploiting g-C3N4-based photocatalysts are presented. This review will deepen the understanding of the state of the art of g-C3N4, including the fabrication, modification, and application in energy and environmental sustainability.

The inferior crystallinity and phase stability of CsPbI2Br films have severely hindered the development of carbon-based, all-inorganic perovskite solar cells (PSCs). Herein, we demonstrate the preparation of CsPbI2Br films by the top-seeded solution growth (TSSG) technique. It is performed through spin-coating of CH3NH3Br (MABr) atop CsPbI2Br precursor film prior to annealing, during which perovskite seeds are generated atop it. These perovskite seeds not only serve as nuclei to regulate the growth of CsPbI2Br grains but also provide additional Br– anions to generate a thin Br-rich layer atop the final CsPbI2Br film. The former contributes to the formation of CsPbI2Br film with full coverage, larger grains, higher crystallinity, and fewer electronic defects, while the latter gives rise to residual compressive strain along the film and thus markedly boosts its phase stability. Consequently, the optimized carbon-based, all-inorganic PSC exhibits a much better efficiency of 14.84% coupled with favored storage and operational stability.

Environmental regulation and green technology are important to mitigate global warming, whereas few studies explored the role of green technology in environmental regulation on carbon intensity. This paper systematically reviews the literature on the relationship among environmental regulation, green technology, and carbon intensity, and assumes that green technology is a potential mediator of the impact of environmental regulation on carbon intensity. The advanced SBM model and the factor analysis method were performed to measure the relationships. To explore the mediating effect of green technology, the two-step econometric model and the nonlinear mediating effect model were applied to a panel dataset of 30 provinces in China spanning the period 2005–2016. The results show that there is an inverted U-shaped relationship between environmental regulation and green technology, and a U-shaped relationship between environmental regulation and carbon intensity. Green technology has a significant negative impact on carbon intensity. This proves that green technology is an important mediating variable on the relationship between environmental regulation and carbon intensity. Moreover, the current environmental regulation intensity lies before the inflection point of both the inverted U-shaped and the U-shaped curves. The effects of environmental regulation on green technology and carbon intensity in developed and developing regions follow an inverted U-shaped, and a U-shaped curve, respectively. Furthermore, the mediating effect in developing regions is significantly larger than that in developed regions. Finally, policy implications are given to reduce carbon intensity.