Photon upconversion via triplet–triplet annihilation (TTA) has achieved high efficiencies in solution and within polymer matrices that support molecular migration systems. It has diverse potential ...applications including bioimaging, optical sensors, and photovoltaics. To date, however, the reported performance of TTA in rigid solid‐state systems is substantially inferior, which may complicate the integration of TTA in other solid‐state devices. Here, solid‐state loss mechanisms in a green‐to‐blue upconversion system are investigated, and three specific losses are identified: energy back transfer, sensitizer aggregation, and triplet–charge annihilation. Strategies are demonstrated to mitigate energy back transfer and sensitizer aggregation, and a completely dry‐processed solid‐state TTA upconversion system having an upconversion efficiency of ≈2.5% (by the convention of maximum efficiency being 100%) at a relatively low excitation intensity of 238 mW cm−2 is reported. This device is the first demonstration of dry‐processed solid‐state TTA comparable to solution‐processed solid‐state systems. The strategies reported here can be generalized to other upconversion systems and offer a route to achieving higher‐performance solid‐state TTA upconversion devices that are compatible with applications sensitive to solvent damage.
Solid‐state triplet–triplet‐annihilation‐based photon‐upconversion systems are subject to losses from back transfer, molecular aggregation, and triplet–charge annihilation. Following strategies provided to mitigate these losses, a dry‐processed solid‐state device having comparable upconversion efficiency and threshold intensity to solution‐processed solid‐state systems is developed, offering a route for high‐performance upconversion devices compatible with applications sensitive to solvent damage.
•The ultra-low emission purification technologies of SO2 in flue gas are described.•The advantages and disadvantages of several desulfurization methods are compared.•The research status of ...desulfurization technology is described.•The mass transfer mechanisms of several desulfurization technologies are reviewed.•The current development problems and future research directions of desulfurization technology are pointed out.
Through the purification technology of flue gas desulfurization, ultralow emissions of SO2 flue gas in industrial flue gas can be achieved. This article involves dry desulfurization, semi-dry desulfurization, and wet desulfurization technologies. The research progress of these technologies since they were first proposed is summarized, and the problems existing in these desulfurization technologies are analyzed. The theory of mass transfer and absorption in flue gas desulfurization is summarized, and the optimal desulfurization process parameters for the operation of desulfurization technology are obtained. A high added value production of desulfurization technology can be realized by studying the recycling of desulfurization products. This paper summarizes the characteristics and the latest research progress of various desulfurization technologies, and aims to provide help for the better development of desulfurization technologies. It also provides suggestions for the future research direction of desulfurization technology.
•Separation processes for RE solvent extraction from aqueous solutions have been reviewed.•Bastnesite, monazite, and xenotime are main sources of RE hydrometallurgical processing.•SX is the main ...technology to separate individual rare earths or produce mixed rare earths.•For process configuration, up to hundreds of stages of mixers and settlers may be used.
Rare earth elements have unique physicochemical properties that make them essential elements in many high-tech components. Bastnesite (La, Ce)FCO3, monazite, (Ce, La, Y, Th)PO4, and xenotime, YPO4, are the main commercial sources of rare earths. Rare earth minerals are usually beneficiated by flotation or gravity or magnetic processes to produce concentrates that are subsequently leached with aqueous inorganic acids, such as HCl, H2SO4, or HNO3. After filtration or counter current decantation (CCD), solvent extraction is usually used to separate individual rare earths or produce mixed rare earth solutions or compounds. Rare earth producers follow similar principles and schemes when selecting specific solvent extraction routes. The use of cation exchangers, solvation extractants, and anion exchangers, for separating rare earths has been extensively studied. The choice of extractants and aqueous solutions is influenced by both cost considerations and requirements of technical performance. Commercially, D2EHPA, HEHEHP, Versatic 10, TBP, and Aliquat 336 have been widely used in rare earth solvent extraction processes. Up to hundreds of stages of mixers and settlers may be assembled together to achieve the necessary separations. This paper reviews the chemistry of different solvent extractants and typical configurations for rare earth separations.
Display omitted
•The corrosion behavior has been explained for Cu-Sn-Pb bronze alloy.•The 79.81Cu-Sn-Pb bronze alloy exhibited the best corrosion resistance.•The corrosion layer on the surface of the ...alloy consists of tin-rich inner layer and metal composite.
The corrosion behaviour of Cu-Sn-Pb bronze alloys in an archaeological-soil medium was examined using electrochemical measurements, microscopy observations and X-ray photoelectron spectroscopy analyses. The corrosion mechanism was mainly composed of the spontaneous dissolution of the base alloy and the formation of surface corrosion products. Results showed that the corrosion rate decreased with increasing Cu content, and the 79.81Cu-Sn-Pb has the lowest corrosion rate among four bronzes examined in this study. The corrosion products of the alloy consisted of two layers, an outer layer of copper, lead oxides and metal chlorides and sulphates, and an inner layer filled with Sn products.
With the development of carbon neutrality strategies, highly polluting and non–renewable fossil fuels are gradually being replaced by electrochemical energy storage systems. Therefore, developing ...high–performance, safe, and green electrochemical energy storage systems has become a research hotspot. Metal–air batteries are a new type of energy storage system with good discharge performance and economic benefits. Magnesium is an energy–storage metal with abundant reserves and low pollution. Its light weight and excellent electrochemical properties make it a key material for energy storage research. Magnesium–air batteries combine the advantages of magnesium and metal–air batteries, with higher energy density, stable discharge, no charging, direct mechanical replacement, and no environmental pollution, highlighting their potential as. Promising energy storage systems. This article reviews the structure and principles of water–based magnesium–air batteries, summarises and compares the optimisation methods for different anodes and cathodes, introduces the development and advantages of magnesium seawater batteries, and discusses the prospects for magnesium–air batteries. Aiming to help researchers understand the current research progress of water–based magnesium–air batteries, discover new research directions based on a comparison of different optimisation methods, and promote the development of magnesium–air battery research, which has important implications for basic research on magnesium–air batteries.
Display omitted
Policy evaluations are crucial in promoting effective administrations. However, evaluations of spatial policies are rare, due to its ambiguity and complexity. Especially when a developmental state ...transitions to democracy, the loss of top-down leadership disables formulation of indicators for evaluations. In such cases, it is essential to search for new evaluation methods and approaches.
This paper introduces a Taiwanese and East Asian context, with a unique historical path toward democracy, which is rarely discussed regarding policy evaluation, especially spatial policy evaluation. As the “hard” developmental states democratize and value more human aspects instead of sheer economic development, compared with “hard” methods such as quantitative impact evaluations, “soft” measures like process evaluation, participatory evaluation and self-assessment may enhance cross-departmental dialogues and connections between policies and executors.
With humans at the center of space use and policy making, this research explores the possibility of bottom-up evaluation without indicators. The new ideas proposed here bridge the vacancies of power dominance in developmental states during transition, and serve as references for such states in current times, especially in the Asian region.
•It is possible to evaluate spatial policies without indicators.•Bottom-up evaluation is more suitable for policies involving multiple stakeholders.•As spatial policies are highly conceptual, process evaluations are more suitable.•Self-evaluation could examine correspondence between execution and policy goals.
Tuft cells were first discovered in epithelial barriers decades ago, but their function remained unclear until recently. In the last 2 years, a series of studies has provided important advances that ...link tuft cells to infectious diseases and the host immune responses. Broadly, a model has emerged in which tuft cells use chemosensing to monitor their surroundings and translate environmental signals into effector functions that regulate immune responses in the underlying tissue. In this article, we review the current understanding of tuft cell immune function in the intestines, airways, and thymus. In particular, we discuss the role of tuft cells in type 2 immunity, norovirus infection, and thymocyte development. Despite recent advances, many fundamental questions about the function of tuft cells in immunity remain to be answered.
Bauxite residue is an alkaline solid waste produced during the extraction of alumina from bauxite, which causes serious environmental problems and safety risks. In this study, alkali and alumina were ...recovered from Bayer bauxite residue using a novel calcification-carbonisation process. This produced a non-hazardous and near-neutral residue (C-C residue), the properties of which facilitated its subsequent reuse. After the calcification-carbonisation treatment, 46.5% of the alumina was extracted and the Na2O content in the final residue (C-C residue) dropped to less than 0.3%. In addition, the feasibility of using C-C residue in the production of cement and the preparation of soil was analysed. The results showed that the chemical composition of C-C residue is very close to that of Portland cement clinker, which allows the dosage of bauxite residue in cement production to be increased. A comparison of the C-C residue with a general soil showed that the former performed well for many soil parameters, such as alkalinity and salinity, and has great potential for application in soil preparation. Thus, the calcification-carbonisation method, combined with cement production or soil preparation, is a sustainable process for completely reusing Bayer bauxite residue and facilitating bauxite waste minimisation.
Display omitted
•A novel C-C process was proposed to recover alkali and alumina from Bayer bauxite residue.•Bauxite residue was transformed structurally into a near-neutral and nonhazardous residue.•The potential use of C-C residue was analysed based on a series of characteristic contrasts.•Extracting metals first and then reusing residue was proposed to realise zero discharge.
The COVID-19 pandemic has impacted the industry immensely and, in some cases, irreversibly. This research pioneers in studying how the pandemic have influenced the survival and spatial distribution ...of the health-related manufacturing industry (HRMI) in Taiwan. Eight categories of HRMI are examined, with their change in survival performances and spatial concentration between 2018 and 2020. Average Nearest Neighbour and Local Indicators of Spatial Association are conducted, to visualise the distribution of industrial clusters. We found the pandemic did not shock the HRMI in Taiwan, but actually induced its growth and spatial concentration to a certain extent. Additionally, due to it being a knowledge-intensive industry, the HRMI mainly concentrate in metropolitan areas with which universities and science parks may have largely supported. However, the spatial concentration and cluster scope growth do not necessarily accompany the improvement of spatial survival, which may be resulted from the different life cycle stages an industry category is in. This research fills in the gap of medical studies with literatures and data from the field of spatial studies. It provides interdisciplinary insights under the condition of pandemic.
PDF
