Exploring new materials and methods to achieve high utilization of sulfur with lean electrolyte is still a common concern in lithium‐sulfur batteries. Here, high‐density oxygen doping chemistry is ...introduced for making highly conducting, chemically stable sulfides with a much higher affinity to lithium polysulfides. It is found that doping large amounts of oxygen into NiCo2S4 is feasible and can make it outperform the pristine oxides and natively oxidized sulfides. Taking the advantages of high conductivity, chemical stability, the introduced large Li–O interactions, and activated Co (Ni) facets for catalyzing Sn2–, the NiCo2(O–S)4 is able to accelerate the Li2S‐S8 redox kinetics. Specifically, lithium‐sulfur batteries using free‐standing NiCo2(O–S)4 paper and interlayer exhibit the highest capacity of 8.68 mAh cm–2 at 1.0 mA cm–2 even with a sulfur loading of 8.75 mg cm–2 and lean electrolyte of 3.8 µL g–1. The high‐density oxygen doping chemistry can be also applied to other metal compounds, suggesting a potential way for developing more powerful catalysts towards high performance of Li–S batteries.
Owing to its high conductivity, chemical stability, and sufficient lithium polysulfide (LiPS) affinity, the high‐density oxygen‐doped sulfide can outperform the pristine oxide and the natively oxidized sulfide in terms of catalyzing LiPS conversion for long cycling of Li–sulfur batteries.
Abstract
Flexible electronics (FEs) with excellent flexibility or foldability may find widespread applications in the wearable devices, artificial intelligence (AI), Internet of Things (IoT), and ...other areas. However, the widely utilization may also bring the concerning for the fast accumulation of electronic waste. Green FEs with good degradability might supply a way to overcome this problem. Starch, as one of the most abundant natural polymers, has been exhibiting great potentials in the development of environmental-friendly FEs due to its inexpensiveness, good processability, and biodegradability. Lots of remarks were made this field but no summary was found. In this review, we discussed the preparation and applications of starch-based FEs, highlighting the role played by the starch in such FEs and the impacts on the properties. Finally, the challenge was discussed and the outlook for the further development was also presented.
Flourishing sales of new electric vehicles have led to a considerable surge in demand for the vital, upstream raw material, lithium (Li). As an essential energy metal and raw material for the ...production of batteries, lithium has become indispensable to the electric vehicle industry. It has been identified as a strategic, emerging industrial mineral in China. Based on a literature review and qualitative analysis of the imbalance between the supply and demand of lithium raw materials in China, this paper analyzes the current challenges of China’s lithium supply chain, especially mining, pricing and recycling, that are obstructing the realization of China’s carbon neutrality. On this basis, relevant policy suggestions are proposed from three perspectives: strengthening lithium resource development and reserve capacity, promoting international cooperation for lithium supply, and properly regulating the circular economy of domestic lithium resources.
Cu and Fe skarns are two economically important types of skarn deposit worldwide, but the critical factors controlling the difference in metal associations remain enigmatic. The Edong ore district, ...China, presents an excellent opportunity to study the differences between Cu–Fe and Fe skarn deposits. We have measured He–Ar isotopes trapped in fluid released by crushing pyrite and chalcopyrite from four well known Cu–Fe and Fe deposits in the Edong district, Eastern China, with the aim of constraining their different fluid source and then discussing the factors controlling their variations between Cu–Fe and Fe skarns.
He–Ar isotopic compositions are markedly different between the Cu–Fe and Fe skarn deposits in the Edong district. 3He/4He ratios in the Cu–Fe deposits are 0.75–1.87Ra and 40Ar/36Ar ratios are 300–472. By contrast, He–Ar isotopic compositions in minerals from the Fe deposits have lower 3He/4He and 40Ar/36Ar ratios of 0.08–0.93Ra and 299–361, respectively. These results suggest that noble gas of the Cu–Fe and Fe skarn deposits in the Edong district formed by variable degrees of mixing between a magmatic fluid containing a mantle component, and modified air–saturated water (MASW). Importantly, He–Ar isotope data provide compelling evidence that contrasting fluid sources were involved in the formation of the Cu–Fe and Fe deposits, i.e., mineralizing fluids of the Cu–Fe deposits could have a greater contribution from mantle component, and little involvement of MASW than those of the Fe deposits in the Edong district. This conclusion is consistent with obvious differences in the nature of the intrusions related to mineralization, as well as sulfur isotopic compositions of sulfides in the Cu–Fe and Fe deposits. It is most likely that different proportion of mantle-derived noble gases play an essential role in controlling differences between the Cu–Fe and Fe skarn deposits.
•He–Ar isotopic compositions are markedly different between the Cu–Fe and Fe skarns.•Noble gas within these Cu–Fe and Fe skarns were derived from mixture between magmatic fluid and MASW.•Different proportion of mantle-derived noble gases between the Cu–Fe and Fe skarns
Resource-based cities, which emerge due to the large-scale industrialization of China, mainly rely on local natural resources for industrial layout and economic development. However, resources have ...been gradually exhausted due to overuse, resulting in a series of negative impacts on the environment and resources. In order to realize long-term sustainable development and avoid falling into the “resource curse,” measures such as industrial structure adjustment and technological upgrading to promote the transformation of these cities ought to be implemented. Taking Benxi, one of the most typical mineral resource-based cities in China, as an example, this study discusses the economic and environmental performance and existing problems in the local transformation process, comparing it with successful transformation patterns of global mineral resource-based cities. On this basis, a series of policy suggestions together with possible ways toward sustainable development are put forward and summarized.
Gastric cancer is the second leading cause of worldwide cancer mortality, yet the underlying genomic alterations remain poorly understood. Here we perform exome and transcriptome sequencing and SNP ...array assays to characterize 51 primary gastric tumours and 32 cell lines. Meta-analysis of exome data and previously published data sets reveals 24 significantly mutated genes in microsatellite stable (MSS) tumours and 16 in microsatellite instable (MSI) tumours. Over half the patients in our collection could potentially benefit from targeted therapies. We identify 55 splice site mutations accompanied by aberrant splicing products, in addition to mutation-independent differential isoform usage in tumours. ZAK kinase isoform TV1 is preferentially upregulated in gastric tumours and cell lines relative to normal samples. This pattern is also observed in colorectal, bladder and breast cancers. Overexpression of this particular isoform activates multiple cancer-related transcription factor reporters, while depletion of ZAK in gastric cell lines inhibits proliferation. These results reveal the spectrum of genomic and transcriptomic alterations in gastric cancer, and identify isoform-specific oncogenic properties of ZAK.
The possible relationship between the thermal stability and the catalytic power of enzymes is of great current interest. In particular, it has been suggested that thermophilic or hyperthermophilic ...(Tm) enzymes have lower catalytic power at a given temperature than the corresponding mesophilic (Ms) enzymes, because the thermophilic enzymes are less flexible (assuming that flexibility and catalysis are directly correlated). These suggestions presume that the reduced dynamics of the thermophilic enzymes is the reason for their reduced catalytic power. The present paper takes the specific case of dihydrofolate reductase (DHFR) and explores the validity of the above argument by simulation approaches. It is found that the Tm enzymes have restricted motions in the direction of the folding coordinate, but this is not relevant to the chemical process, since the motions along the reaction coordinate are perpendicular to the folding motions. Moreover, it is shown that the rate of the chemical reaction is determined by the activation barrier and the corresponding reorganization energy, rather than by dynamics or flexibility in the ground state. In fact, as far as flexibility is concerned, we conclude that the displacement along the reaction coordinate is larger in the Tm enzyme than in the Ms enzyme and that the general trend in enzyme catalysis is that the best catalyst involves less motion during the reaction than the less optimal catalyst. The relationship between thermal stability and catalysis appears to reflect the fact that to obtain small electrostatic reorganization energy it is necessary to invest some folding energy in the overall preorganization process. Thus, the optimized catalysts are less stable. This trend is clearly observed in the DHFR case.
A new type of light‐switchable “smart” single‐walled carbon nanotube (SWNTs) is developed by the reversible host–guest interaction between azobenzene‐terminal PEO (AzoPEO) and pyrene‐labeled host ...attached on the sidewalls of nanotubes via π–π stacking. The SWNTs hybrids not only are well dispersed in pure water, but also exhibit switchable dispersion/aggregation states upon the alternate irradiation of UV and visible light. Moreover, the SWNTs hybrids dispersion is preliminarily used as coating fluid to form transparent conductive films. The dispersant AzoPEO is removed by the contamination‐free UV treatment, decreasing the resistance of the films. This kind of light‐switchable SWNTs hybrids, possessing a ‘‘green’’ trigger and intact structure of the nanotube, may find potential applications in sensor of biomedicines, device fabrication, etc. Additionally, such a reversible host–guest interaction system may open up the possibility to control the dispersion state of SWNTs by other common polymers.
A new type of “smart” single‐walled carbon nanotube (SWNT) is created by combining reversible host–guest interaction and noncovalent π–π stacking. The SWNTs hybrids not only are well dispersed in pure water, but they also exhibit switchable dispersion/aggregation states upon the alternate irradiation with UV and visible light in pure water.
Based on the analysis of the typical Ordos well groups, this study began with the accurate characterization of the fracture geometry by adopting advanced laboratory experiment methods and monitoring ...techniques. Then, with the integration of fracture geometry characterization and in situ stress distributions, fracture optimizations of the target wells were performed through numerical simulations methods. Finally, this study established a sweet spot prediction and identification method for long horizontal shale oil wells and constructed a set of optimization design methods for multistage hydraulic fracturing. This investigation revealed that the hydraulic fractures in Chang-7 terrestrial shale oil reservoirs exhibited the belt pattern, and the primary fractures generated the secondary fractures, which activated the natural fractures and induced shear failure. Macroscopic fractures were found to be perpendicular to the direction of the minimum principal stress. Secondary fractures and activated natural fractures were distributed around the primary fracture in the form of fracture types I and II. Multicluster perforation optimization techniques, which were based on shale reservoir classification and evaluation, and aimed at activating multiclusters and determining fracture sweet spots, were developed. These were successfully applied to the field operation and achieved production enhancement performance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Hierarchically porous carbonaceous sponges and their magnetic nanocomposites were fabricated by a combined approach of hydrothermal carbonization and freeze drying. The resulting carbonaceous sponges ...have hierarchically porous structure and a large number of oxygen-containing functional groups. The unique structure enables carbonaceous sponges candidate materials for rapid and efficient organic molecules removal from water.
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•The CS is sustainable, inexpensive and hierarchically porous.•The CS exhibits excellent adsorption capacities toward organic molecules.•Convenient solid–liquid separation after removal of organic molecules is achieved by introducing Fe3O4 NPs into CS network.
This work describes the preparation, characterization and removal capability of a novel biomass derived carbonaceous sponges (CS) and their nanocomposites. The CS has hierarchically porous structure which is composed of lamellar structures and secondary porous structures. The pore size is on a scale from 1nm to 200μm. Utilizing the CS as adsorbents, rapid removal of model organic molecules, including methylene blue (MB), methyl orange (MO) and crystal violet (CV), from their aqueous solutions can be completed within 1min with the assistance of pressure and the removal efficiency reaches up to 100%, 81% and 98%, respectively. The removal capabilities for CS towards MB, MO and CV are 0.0769g/g, 0.2218g/g and 1.0384g/g, respectively and 0.0635g/g, 0.0977g/g and 0.8634g/g, respectively for CS nanocomposites.
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