A high production yield CDs was synthesized by waste plastic (polystyrene) with a large full width at half maximum of 150–200 nm, exhibited tunable photoluminescence from white to yellow and orange. ...CDs powder was used to fabricate single-component white and multi-color light-emitting diodes on UV chips. This investigation not only proves that solid-state fluorescent CDs have broad application prospects, but also provides a feasible method for recycling plastic waste.
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Plastic waste is generally resistant to natural degradation and has become a major environmental pollution problem globally. The pollution of ecosystems seriously affects the health and survival of organisms, including humans. Much attention has been paid to finding suitable ways to convert plastic waste into high-value-added carbon materials. To this end, we report the high production yield (60%–85%) of carbon dots (CDs) for solid-state fluorescence (SSF) obtained by a one-step solvothermal method using waste expanded polystyrene as the precursor. The SSF mechanism of the CDs was also explored. Their emission wavelength, with a large full width at half maximum of 150–200 nm, exhibited tunable photoluminescence from white to yellow and orange. CDs powder was used to fabricate single-component white and multi-colour light-emitting diodes on UV chips. Overall, plastic waste was converted into tunable solid-state fluorescent CDs powder, which has promising applications in carbon-based lighting, by a simple solvothermal method that provides a viable method for recycling plastic waste.
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Tandem electrocatalysis is an emerging concept for effective electrochemical CO2 reduction reaction (CO2RR) towards multicarbons (C2+). This decouples the multiple steps of CO2-to-C2+ ...into two steps of CO2-to-CO and CO-to-C2+ catalyzed by individual catalysts, to improve the Faradic efficiency (FE). However, due to the mass-transport limitation of CO from the generation site to the long-distance consumption site, such a strategy still remains challenge for high-rate production of C2+ products. Herein, we designed CuO/Ni single atoms tandem catalyst, which made the catalytic sites of Ni and Cu for independently catalyzing CO2-to-CO and CO-to-C2+ compactly neighbored, enabling the in-situ generation and rapid consumption of CO. The CuO/Ni SAs tandem catalyst achieved a particularly high partial current density of C2+ products (1220.8 mA/cm2), while still maintained outstanding C2+ products FE (81.4%) and excellent selectivities towards ethylene (FE 54.1%) and ethanol (FE 28.8%), enabling the profitable production of multicarbons by CO2RR.
SUMMARY
Photosynthesis is a key process in sustaining plant and human life. Improving the photosynthetic capacity of agricultural crops is an attractive means to increase their yields. While the core ...mechanisms of photosynthesis are highly conserved in C3 plants, these mechanisms are very flexible, allowing considerable diversity in photosynthetic properties. Among this diversity is the maintenance of high photosynthetic light‐use efficiency at high irradiance as identified in a small number of exceptional C3 species. Hirschfeldia incana, a member of the Brassicaceae family, is such an exceptional species, and because it is easy to grow, it is an excellent model for studying the genetic and physiological basis of this trait. Here, we present a reference genome of H. incana and confirm its high photosynthetic light‐use efficiency. While H. incana has the highest photosynthetic rates found so far in the Brassicaceae, the light‐saturated assimilation rates of closely related Brassica rapa and Brassica nigra are also high. The H. incana genome has extensively diversified from that of B. rapa and B. nigra through large chromosomal rearrangements, species‐specific transposon activity, and differential retention of duplicated genes. Duplicated genes in H. incana, B. rapa, and B. nigra that are involved in photosynthesis and/or photoprotection show a positive correlation between copy number and gene expression, providing leads into the mechanisms underlying the high photosynthetic efficiency of these species. Our work demonstrates that the H. incana genome serves as a valuable resource for studying the evolution of high photosynthetic light‐use efficiency and enhancing photosynthetic rates in crop species.
Significance Statement
Hirschfeldia incana is a diploid, wild species, closely related to Brassica crops, which displays remarkably high photosynthesis rates at high irradiance, a desirable trait to improve in crops to increase yield. We propose H. incana as an attractive high‐photosynthesis model species and present the reference genome sequence as a valuable resource for studying the evolution, genetics, and physiology of high photosynthetic light‐use efficiency at high irradiances.
Intercropping is one of the most vital practice to improve land utilization rate in China that has limited arable land resource. However, the traditional intercropping systems have many disadvantages ...including illogical field lay-out of crops, low economic value, and labor deficiency, which cannot balance the crop production and agricultural sustainability. In view of this, we developed a novel soybean strip intercropping model using maize as the partner, the regular maize-soybean strip intercropping mainly popularized in northern China and maize-soybean relay-strip intercropping principally extended in southwestern China. Compared to the traditional maize-soybean intercropping systems, the main innovation of field lay-out style in our present intercropping systems is that the distance of two adjacent maize rows are shrunk as a narrow strip, and a strip called wide strip between two adjacent narrow strips is expanded reserving for the growth of two or three rows of soybean plants. The distance between outer rows of maize and soybean strips are expanded enough for light use efficiency improvement and tractors working in the soybean strips. Importantly, optimal cultivar screening and increase of plant density achieved a high yield of both the two crops in the intercropping systems and increased land equivalent ratio as high as 2.2. Annually alternative rotation of the adjacent maize- and soybean-strips increased the grain yield of next seasonal maize, improved the absorption of nitrogen, phosphorus, and potasium of maize, while prevented the continuous cropping obstacles. Extra soybean production was obtained without affecting maize yield in our strip intercropping systems, which balanced the high crop production and agricultural sustainability.
Marine shale gas resources have great potential in the south of the Sichuan Basin in China. At present, the high-quality shale gas resources at depth of 2000–3500 m are under effective development, ...and strategic breakthroughs have been made in deeper shale gas resources at depth of 3500–4500 m. To promote the effective production of shale gas in this area, this study examines key factors controlling high shale gas production and presents the next exploration direction in the southern Sichuan Basin based on summarizing the geological understandings from the Lower Silurian Longmaxi Formation shale gas exploration combined with the latest results of geological evaluation. The results show that: (1) The relative sea depth in marine shelf sedimentary environment controls the development and distribution of reservoirs. In the relatively deep water area in deep-water shelf, grade-I reservoirs with a larger continuous thickness develop. The relative depth of sea in marine shelf sedimentary environment can be determined by redox conditions. The research shows that the uranium to thorium mass ratio greater than 1.25 indicates relatively deep water in anoxic reduction environment, and the uranium to thorium mass ratio of 0.75–1.25 indicates semi-deep water in weak reduction and weak oxidation environment, and the uranium to thorium mass ratio less than 0.75 indicates relatively shallow water in strong oxidation environment. (2) The propped fractures in shale reservoirs subject to fracturing treatment are generally 10–12 m high, if grade-I reservoirs are more than 10 m in continuous thickness, then all the propped section would be high-quality reserves; in this case, the longer the continuous thickness of penetrated grade-I reservoirs, the higher the production will be. (3) The shale gas reservoirs at 3500–4500 m depth in southern Sichuan are characterized by high formation pressure, high pressure coefficient, well preserved pores, good pore structure and high proportion of free gas, making them the most favorable new field for shale gas exploration; and the pressure coefficient greater than 1.2 is a necessary condition for shale gas wells to obtain high production. (4) High production wells in the deep shale gas reservoirs are those in areas where Long11– Long13 sub-beds are more than 10 m thick, with 1500 m long horizontal section, grade-I reservoirs penetration rate of over 90%, and fractured by dense cutting + high intensity sand injection + large displacement + large liquid volume. (5) The relatively deep-water area in the deep-water shelf and the area at depth of 3500–4500 m well overlap in the southern Sichuan, and the overlapping area is the most favorable shale gas exploration and development zones in the southern Sichuan in the future. With advancement in theory and technology, annual shale gas production in the southern Sichuan is expected to reach 450×108 m3.
Based on the understandings on enrichment rules of marine shale gas in southern China and data obtained from exploration and development in Fuling shale gas field, this article discusses the key ...controlling factors on shale gas enrichment and their relationships, it also discusses further the theory of Two-Factor Enrichment of marine shale gas in southern China. The bases for shale gas enrichment are shale gas generation and accumulation, the shale gas reservoirs of deep-water shelf are characterized by high TOC, high porosity, high gas contents and high siliceous contents, with high hydrocarbon-generation intensity. The organic pores are rich in shales in favorable for stimulation, so they are the bases for large scale hydrocarbon accumulation. Preservation conditions are vital to the formation and enrichment of shale gas reservoirs, good top and base layers can effectively prevent hydrocarbon from escaping vertically at the beginning of hydrocarbon generation. Shale gas preservation conditions depend on the intensity and duration of tectonic movements, good preservation conditions are key geological factors for shale gas accumulation, shale reservoirs have high gas contents, high porosity and high pressure and are likely to form high yield area of shale gas.
The extended use of chemicals in both consumer and industrial products has led to a widespread ubiquity of compounds listed as high production volume chemicals (HPVs). Organophosphate esters, ...phthalate esters, benzothiazoles and benzotriazoles are part of this list, intended to prioritize their study to evaluate population's safety. Their fate throughout the environment reaches seafood, thus becoming accessible to the population via dietary intake. The reported negative effects led to the development of selective and sensitive methods capable of determining these compounds. The present review compiles the most used analytical methods for the determination of HPVs in seafood, mainly based on solid-liquid extraction, QuEChERS or pressurized liquid extraction, as extraction techniques, among others. The utility of efficient clean-up strategies is also discussed, aiming for reliable determinations while maintaining the instruments efficiency. Finally, an overview of the occurrence of these compounds in seafood and the exposure and risk associated to their ingestion is also discussed.
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•Widespread ubiquity of HPVs in seafood has been recently put on the spotlight.•QuEChERS and d-SPE are efficient seafood extraction and clean-up strategies.•HPVs dietary intake via seafood represents a minor risk for population.•Future perspectives rely on greener seafood analysis methodologies.
High pressure difference, high flow rate, and high sand content in throttling manifolds of high-pressure and high-production gas wells make the problems of high-speed gas-solid erosion wear ...especially prominent. The failure of the throttling manifold is frequent, which is easy to induce overflow, kick, and blowout accidents, aggravates well-controlled risks, and brings safety risks. Therefore, according to ASTM G76–2013, this paper adopts the gas-solid nozzle erosion test method and air jet erosion test rig. The high speed (107 m/s-49 m/s) gas-solid nozzle erosion test of 30CrMo alloy steel was carried out under different inlet pressures (0.06 MPa–0.15 MPa) and impact Angle (15°-90°), and the erosion rate of 30CrMo alloy steel under different experimental conditions was obtained. The erosion rate equation of 30CrMo alloy steel suitable for high-speed solid particle impact is established. Based on the results of erosion experiments, the optimal particle motion model for high-speed compressible flow is constructed. Combined with the discrete phase model (DPM) and gas-solid two-phase coupling calculation method, a three-dimensional CFD erosion model of the “reduced-tuber-nozzle-erosion cavity” was established. The erosion simulation of the gas-solid nozzle of 30CrMo alloy steel, a throttling manifold material, was carried out at different impact angles (15°-90°) and inlet pressure (0.06 MPa–0.15 MPa), and the distribution characteristics of the flow field, particle movement trajectory, impact velocity distribution, and slip characteristics were revealed. The accuracy and reliability of the CFD erosion model and simulation results have been validated by test data.
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•High-speed gas-solid erosion test of choke manifold material is conducted.•Erosion rate equation of 30CrMo suitable for high-speed particle impact is created.•Optimal particle motion model suitable for high-speed compressible flow is presented.•3D CFD erosion model of “reducing tube-spray nozzle-erosion chamber” is established.•Flow field, particle trajectory, erosion morphology and erosion rate are obtained.
The Wufeng Formation–Longmaxi Formation in the Sichuan Basin in South China is the key stratum for shale gas exploration and production. To date, three national shale gas demonstration zones have ...been developed. Nevertheless, there are still some test wells that have not yet been commercialized. In this study, the geological characteristics of commercial and non-commercial zones are analyzed, as are the main controlling factors of high-producing wells (high estimated ultimate recovery; EUR), and the reasons for low-production wells (low EUR) by dissecting the three national shale gas demonstration zones and the main shale gas exploration wells. The results of this study indicate the following: (1) The black shale in the WF2–LM4 graptolite zone is deposited in the Craton depression on the Upper Yangtze plate, which provides a relatively stable tectonic environment for tectonic deformation and uplift destruction. The large shale thickness and weak tectonic activity jointly result in shale gas being enriched mainly in the deep-water shelf. (2)The regional fault has a destructive effect on shale gas preservation, and the shale gas reservoir is likely to be destroyed. In the areas close to the regional fault, multiple fracture-fluid migration activities caused by multistage tectonic movements are also detrimental to shale gas preservation. Conversely, shale gas is generally well preserved in areas far from regional faults. (3) The black shale thickness in the WF2–LM4 graptolite zone in the deep-water shelf area controls the shale gas field distribution. Furthermore, the horizontal well trajectory in the WF2–LM4 graptolite zone determines the shale gas well test production and EUR. The results of this work will provide a reference for shale gas exploration and development of the Wufeng Formation–Longmaxi Formation in the Sichuan Basin, as well as the Silurian strata in other parts of the world.
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