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1.
Small ; 20(6): e2306104, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37775948

RESUMEN

Microwave absorbers with high efficiency and mechanical robustness are urgently desired to cope with more complex and harsh application scenarios. However, manipulating the trade-off between microwave absorption performance and mechanical properties is seldom realized in microwave absorbers. Here, a chemistry-tailored charge dynamic engineering strategy is proposed for sparking hetero-interfacial polarization and thus coordinating microwave attenuation ability with the interfacial bonding, endowing polymer-based composites with microwave absorption efficiency and mechanical toughness. The absorber designed by this new conceptual approach exhibits remarkable Ku-band microwave absorption efficiency (-55.3 dB at a thickness of 1.5 mm) and satisfactory effective absorption bandwidth (5.0 GHz) as well as desirable interfacial shear strength (97.5 MPa). The calculated differential charge density depicts the uneven distribution of space charge and the intense hetero-interfacial polarization, clarifying the structure-performance relationship from a theoretical perspective. This work breaks through traditional single performance-oriented design methods and ushers a new direction for next-generation microwave absorbers.

2.
Environ Res ; 216(Pt 3): 114701, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-36332670

RESUMEN

To reduce the heavy dependence on petroleum, bioethanol has been increasingly employed as an alternative and sustainable transportation fuel. However, the characteristics of black carbon (BC) emissions from E10 petrol vehicles (i.e., ethanol-gasoline containing 10% ethanol) are still unclear, especially under real driving conditions. Here, a tunnel test was conducted during a cold winter. This tunnel was characterized by heavy traffic comprising more than 98% E10-fueled gasoline vehicles (GVs). Real-time BC concentrations, traffic parameters and meteorological conditions were recorded during the sampling campaign. The average BC concentration inside the tunnel (10.94 ± 5.02 µg m-3) was almost twice the background concentration. Based on aethalometer AE33 in situ measurements and the minimum R-squared (MRS) method, real-time aerosol light absorption was apportioned. The light absorption proportions of BC, primary brown carbon (BrC1) and secondary brown carbon (BrC2) were 79.86%, 2.78% and 17.36%, respectively, at 370 nm. The BC emission factor (EFBC) of the E10-fueled vehicles was 1.09 ± 0.49 mg km-1·veh-1 and 15.24 ± 6.85 mg·(kg fuel)-1, lower than those of traditional gasoline fueled vehicles in previous studies. This study can support the compilation of vehicular BC emission inventories, provide recommendations for biofuel policies and contribute to comprehensively understanding the climatic impact of E10 petrol.


Asunto(s)
Contaminantes Atmosféricos , Gasolina , Gasolina/análisis , Contaminantes Atmosféricos/análisis , Emisiones de Vehículos/análisis , Aerosoles/análisis , Hollín/análisis , Carbono/análisis , Etanol/análisis , Monitoreo del Ambiente/métodos
3.
Sensors (Basel) ; 23(17)2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37688111

RESUMEN

Enhancing gasoline detergency is pivotal for enhancing fuel efficiency and mitigating exhaust emissions in gasoline vehicles. This study investigated gasoline vehicle emission characteristics with different gasoline detergency, explored synergistic emission reduction potentials, and developed versatile emission prediction models. The results indicate that improved fuel detergency leads to a reduction of 5.1% in fuel consumption, along with decreases of 3.2% in total CO2, 55.4% in CO, and 15.4% in HC emissions. However, during low-speed driving, CO2 and CO emissions reductions are limited, and HC emissions worsen. A synergistic emission reduction was observed, particularly with CO exhibiting a pronounced reduction compared to HC. The developed deep-learning-based vehicle emission model for different gasoline detergency (DPVEM-DGD) enables accurate emission predictions under various fuel detergency conditions. The Pearson correlation coefficients (Pearson's r) between predicted and measured values of CO2, CO, and HC emissions before and after adding detergency agents are 0.913 and 0.934, 0.895 and 0.915, and 0.931 and 0.969, respectively. The predictive performance improves due to reduced peak emissions resulting from improved fuel detergency. Elevated gasoline detergency not only reduces exhaust emissions but also facilitates more refined emission management to a certain extent.

4.
Waste Manag Res ; 41(10): 1549-1558, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37070218

RESUMEN

Technology for recycling retired lithium batteries has become increasingly environment-friendly and efficient. In traditional recovery methods, pyrometallurgy or hydrometallurgy is often used as an auxiliary treatment method, which results in secondary pollution and increases the cost of harmless treatment. In this article, a new method for combined mechanical recycling of waste lithium iron phosphate (LFP) batteries is proposed to realize the classification and recycling of materials. Appearance inspections and performance tests were conducted on 1000 retired LFP batteries. After discharging and disassembling the defective batteries, the physical structure of the cathode binder was destroyed under ball-milling cycle stress, and the electrode material and metal foil were separated using ultrasonic cleaning technology. After treating the anode sheet with 100 W of ultrasonic power for 2 minutes, the anode material was completely stripped from the copper foil, and no cross-contamination between the copper foil and graphite was observed. After the cathode plate was ball-milled for 60 seconds with an abrasive particle size of 20 mm and then ultrasonically treated for 20 minutes with a power of 300 W, the stripping rate of the cathode material reached 99.0%, and the purities of the aluminium foil and LFP reached 100% and 98.1%, respectively.


Asunto(s)
Cobre , Litio , Suministros de Energía Eléctrica , Reciclaje/métodos , Electrodos , Hierro , Fosfatos
5.
Environ Res ; 200: 111463, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34111436

RESUMEN

The Chinese government has developed an ambitious project to promote the application of ethanol gasoline (E10) on a national scale since 2017. Given the difference in fuel properties between E10 and traditional gasoline, it is necessary to evaluate the volatile organic compound (VOC) emissions from E10-fuelled vehicles. In this study, a two-week sampling campaign was conducted in an urban tunnel, in which E10-fuelled vehicles were dominant, to evaluate the characteristics of VOC emissions from the mixed fleet. In total, 105 VOC species were identified, and the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) were estimated. The results showed that for vehicular VOC concentrations in the tunnel, alkanes, oxygenated VOCs (OVOCs) and alkenes were the most abundant VOC groups, with the average proportion being more than 80% of the total VOCs. The fleet-average VOC emission factor (EF) was 14.8 mg/km/veh, which was much lower than that from traditional gasoline-fuelled vehicle fleets, and alkanes, OVOCs, alkenes and aromatics were the major VOC groups. Because of the large number of E10-fuelled vehicles in the mixed fleet, a high proportion of OVOCs among the vehicular VOC emissions was observed. Ethane, acrolein, ethanol, ethylene and toluene were the top five VOC species with the largest EF in VOC emissions from the fleet. Alkenes were the main contributors with an average contribution of 43.9% of the total OFP, whereas aromatics dominated the total SOAFP by 95.8% on average. These results may provide a reference for the extensive application of ethanol gasoline and the development of vehicular emission models.


Asunto(s)
Contaminantes Atmosféricos , Ozono , Compuestos Orgánicos Volátiles , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , China , Monitoreo del Ambiente , Ozono/análisis , Emisiones de Vehículos/análisis , Compuestos Orgánicos Volátiles/análisis
6.
Waste Manag Res ; 39(9): 1164-1173, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33407040

RESUMEN

Lithium iron phosphate (LFP) batteries contain metals, toxic electrolytes, organic chemicals and plastics that can lead to serious safety and environmental problems when they are improperly disposed of. The published literature on recovering spent LFP batteries mainly focuses on policy-making and conceptual design. The production line of recovering spent LFP batteries and its detailed operation are rarely reported. A set of automatic line without negative impact to the environment for recycling spent LFP batteries at industrial scale was investigated in this study. It includes crushing, pneumatic separation, sieving, and poison gas treatment processes. The optimum retaining time of materials in the crusher is 3 minutes. The release rate is the highest when the load of the impact crusher is 800 g. An air current separator (ACS) was designed to separate LFP from aluminium (Al) foil and LFP powder mixture. Movement behaviour of LFP powder and Al foil in the ACS were analysed, and the optimized operation parameter (35.46 m/s) of air current speed was obtained through theoretical analysis and experiments. The weight contents of an Al foil powder collector from vibrating screen-3 and LFP powder collector from bag-type dust collector are approximately 38.7% and 52.4%, respectively. The economic cost of full manual dismantling is higher than the recovery production line. This recycling system provides a feasible method for recycling spent LFP batteries.


Asunto(s)
Aluminio , Litio , Suministros de Energía Eléctrica , Electrodos , Hierro , Fosfatos , Reciclaje
7.
Waste Manag Res ; 39(1): 146-155, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32938335

RESUMEN

Spent lithium iron phosphate (LFP) batteries contain abundant strategic lithium resources and are thus considered attractive secondary lithium sources. However, these batteries may contaminate the environment because they contain hazardous materials. In this work, a novel process involving low-temperature heat treatment is used as an alternative pretreatment method for recycling spent LFP batteries. When the temperature reaches 300°C, the dissociation effect of the anode material gradually improves with heat treatment time. At the heat treatment time of 120 minutes, an electrode material can be dissociated. The extension of heat treatment time has a minimal effect on quality loss. The physicochemical changes in thermally treated solid cathode and anode materials are examined through scanning electron microscopy with energy-dispersive X-ray spectroscopy. The heat treatment results in the complete separation of the materials from aluminium foil without contamination. The change in heat treatment temperature has a small effect on the quality of LFP material shedding. When the heat treatment temperature reaches 300°C and the time reaches 120 minutes, heat treatment time increases, and the yield of each particle size is stable and basically unchanged. The method can be scaled up and may reduce environmental pollution due to waste LFP batteries.


Asunto(s)
Suministros de Energía Eléctrica , Litio , Electrodos , Hierro , Fosfatos , Reciclaje , Temperatura
8.
Waste Manag Res ; 38(8): 911-920, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32552572

RESUMEN

The consumption of lithium iron phosphate (LFP)-type lithium-ion batteries (LIBs) is rising sharply with the increasing use of electric vehicles (EVs) worldwide. Hence, a large number of retired LFP batteries from EVs are generated annually. A recovery technology for spent LFP batteries is urgently required. Compared with pyrometallurgical, hydrometallurgical and biometallurgical recycling technologies, physical separating technology has not yet formed a systematic theory and efficient sorting technology. Strengthening the research and development of physical separating technology is an important issue for the efficient use of retired LFP batteries. In this study, spent LFP batteries were discharged in 5 wt% sodium chloride solution for approximately three hours. A specially designed machine was developed to dismantle spent LFP batteries. Extending heat treatment time exerted minimal effect on quality loss. Within the temperature range of 240°C-300°C, temperature change during heat treatment slightly affected mass loss. The change in heat treatment temperature also had negligible effect on the shedding quality of LFP materials. The cathode material and the aluminium foil current collector accounted for a certain proportion in a sieve with a particle size of -1.25 + 0.40 mm. Corona electrostatic separation was performed to separate the metallic particles (with a size range of -1.5 + 0.2 mm) from the nonmetallic particles of crushed spent LFP batteries. No additional reagent was used in the process, and no toxic gases, hazardous solid waste or wastewater were produced. This study provides a complete material recovery process for spent LFP batteries.


Asunto(s)
Suministros de Energía Eléctrica , Litio , Electrodos , Hierro , Fosfatos , Reciclaje
9.
Waste Manag Res ; 37(12): 1217-1228, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31486742

RESUMEN

With the rapid development of the electric vehicle market since 2012, lithium-iron phosphate (LFP) batteries face retirement intensively. Numerous LFP batteries have been generated given their short service life. Thus, recycling spent LFP batteries is crucial. However, published information on the recovery technology of spent LFP batteries is minimal. Traditional separators and separation theories of recovering technologies were unsuitable for guiding the separation process of recovering metals from spent LFP batteries. The separation rate of the current method for recovering spent LFP batteries was rather low. Furthermore, some wastewater was produced. In this study, spent LFP batteries were dismantled into individual parts of aluminium shells, cathode slices, polymer diaphragms and anode slices. The anode pieces were scraped to separate copper foil and anode powder. The cathode pieces were thermally treated to reduce adhesion between the cathode powder and the aluminium foil. The dissociation rate of the cathode slices reached 100% after crushing when the temperature and time reached 300℃ and 120 min, respectively. Eddy current separation was performed to separate nonferrous metals (aluminium) from aluminium and LFP mixture. The optimized operation parameters for the eddy current separation were feeding speed of 1 m/s and magnetic field rotation speed of 4 m/s. The separation rate of the eddy current separation reached 100%. Mass balance of the recovered materials was conducted. Results showed that the recovery rate of spent LFP can reach 92.52%. This study established a green and full material recovery process for spent LFP batteries.


Asunto(s)
Aluminio , Litio , Suministros de Energía Eléctrica , Electrodos , Hierro , Fosfatos , Reciclaje
10.
Waste Manag Res ; 37(4): 374-385, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30726173

RESUMEN

A novel approach to recycling of copper and aluminum fragments in the crushed products of spent lithium iron phosphate batteries was proposed to achieve their eco-friendly processing. The model of pneumatic separation that determines the optimal airflow velocity was established using aerodynamics. The influence of the airflow velocity, and the density and thickness, and their ratios, of the aluminum and copper fragments on pneumatic separation were evaluated. The results show that the optimal airflow velocities of copper and aluminum fragments with and without the electrode materials are 3.27m/s and 1.67m/s, respectively. The accuracy and reliability of the present model was verified using a pneumatic separation experiment. It is concluded that graded pneumatic separation is unnecessary for the crushed particle size more than 9 mm. The experimentally determined optimal airflow velocity of the copper and aluminum fragments with and without the electrode materials is 3.3m/s and 1.7m/s, respectively. The mass fractions of the copper and aluminum fragments upon removal of the electrode materials after pneumatic separation are 97% and 96%, respectively, and both with the electrode material achieve 97.0%. The theoretically obtained optimal airflow velocities have good agreements with the experimentally obtained ones.


Asunto(s)
Litio , Reciclaje , Suministros de Energía Eléctrica , Electrodos , Hierro , Fosfatos , Reproducibilidad de los Resultados
11.
Waste Manag Res ; 37(8): 767-780, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31218930

RESUMEN

The recycling processes of spent lithium iron phosphate batteries comprise thermal, wet, and biological and mechanical treatments. Limited research has been conducted on the combined mechanical process recycling technology and such works are limited to the separation of metal and non-metal materials, which belongs to mechanical recovery. In this article the combined mechanical process recycling technology of spent lithium iron phosphate batteries and the separation of metals has been investigated. The spent lithium iron phosphate batteries monomer with the completely discharged electrolyte was subjected to perforation discharge. The shell was directly recycled and the inner core was directly separated into a positive electrode piece, dissepiment, and negative electrode piece. The dissociation rate of the positive and negative materials reached 100.0% after crushing when the temperature and time reached 300 °C and 120 min. The crushed products were collected and sequentially sieved after the low-temperature thermal treatment. Then, nonferrous metals (copper and aluminium) were separated from the crushed spent lithium iron phosphate batteries by eddy current separation with particle size -4 + 0.4. The optimised operation parameters of eddy current separation were fed at speeds of 40 r min-1, and the rotation speed of the magnetic field was 800 r min-1. The nonferrous metals of copper and aluminium were separated by the method of pneumatic separation. The optimal air speed was 0.34 m s-1 for the particle-size -1.6 + 0.4 mm and 12.85-14.23 m s-1 for the particle-size -4 + 1.6 mm. The present recycling process is eco-friendly and highly efficient and produces little waste.


Asunto(s)
Aluminio , Litio , Cobre , Suministros de Energía Eléctrica , Hierro , Fenómenos Mecánicos , Fosfatos , Reciclaje
12.
J Nanosci Nanotechnol ; 17(1): 507-16, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29625521

RESUMEN

The mesoporous manganese dioxide with high specific surface area was obtained through a one-pot prepare procedure at ambient temperature under acidic conditions. And the graphene/mesoporous manganese dioxide composite was synthesized by a simple hydrothermal approach. As a comparison, silver nanowires also as a conductor was added to the mesoporous manganese dioxide. Both of the graphene and silver nanowires can increase the capacitance of the mesoporous manganese dioxide-based composite electrode materials. Compared with the graphene/mesoporous manganese dioxide composite, the silver nanowires/mesoporous manganese dioxide mixture has a better electrochemical performance, the specific capacitance and energy density is almost 2.2 times larger than that of the composites. The morphology and detail structure were investigated by the Scanning electron microscopy, X-ray diffraction, Raman spectra, Fourier transform infrared spectrometry and Nitrogen adsorption­desorption isotherms. The electrochemical performance was assessed by the cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy.

13.
J Environ Sci (China) ; 48: 193-199, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27745664

RESUMEN

The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0-10km/hr were increased to 10-20km/hr, the CO2, CO, nitrogen oxide (NOx), and total hydrocarbon (THC) emission factors decreased by (71.6±4.3)%, (65.6±9.5)%, (64.9±9.2)% and (67.8±0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0-10km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO2 and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Gas Natural , Emisiones de Vehículos/análisis , China , Ciudades , Hidrocarburos/análisis , Óxidos de Nitrógeno/análisis
14.
Ecotoxicol Environ Saf ; 104: 220-5, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24726932

RESUMEN

The effect of concurrent degradation of tetrabromobisphenol A (TBBPA) by the strain Ochrobactrum sp. T under aerobic condition was investigated. The results demonstrated that four extra energy source-addition systems still followed pseudo-first order kinetics. The addition of ethanol or glucose could promote the biodegradation ability of Ochrobactrum sp. T to TBBPA, and 90.1 percent and 77.5 percent of TBBPA (5mg L(-1)) could be removed with corresponding TBBPA half-lives of 26 and 36h, respectively, after 96h reaction. Comparatively, the degradation efficiency of the sole TBBPA system was only 72.9 percent under the same condition. In contrast, two other co-substrates 2,4,6-tribromophenol (TBP) and bisphenol A (BPA) showed a negative effect on the TBBPA biodegradation, and the degradation efficiencies of TBBPA were achieved as 44.7 percent and 67.4 percent, respectively. For the TBBPA+TBP system, the competitive inhibition for the TBBPA debromination was less than the inhibition of the toxicity to the bacterium. While for the TBBPA+BPA system, the degradation of TBBPA could be promoted at the beginning of the reaction, and was then inhibited slightly with further prolonging of reaction time. This is probably due to the substrates being oxidized, and BPA can consume partial oxygen and provide the electrons during the concurrent biodegradation process. In addition, although higher estrogenic activity could be detected for the debrominated intermediates in TBBPA co-degradation process than the original TBBPA, the estrogenicity of the whole system still decreased finally after 96h degradation.


Asunto(s)
Ochrobactrum/metabolismo , Bifenilos Polibrominados/metabolismo , Aerobiosis , Compuestos de Bencidrilo/química , Biodegradación Ambiental , Contaminantes Ambientales/metabolismo , Estrógenos/química , Fenoles/química
15.
ACS Appl Mater Interfaces ; 16(19): 24781-24795, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38695117

RESUMEN

Aqueous zinc-ion batteries (ZIBs) are regarded as a type of promising energy-storage device because of their high safety and low cost, and polyaniline (PANI) is normally employed as a cathode material for ZIBs owing to its unique electrochemical properties and high environmental stability. However, a low specific capacity and a short cycle life limit the development and applications of PANI-based electrodes. Herein, we have developed a novel type of highly stable PANI-based cathode material enabled by phosphene (PR) for aqueous Zn-PANI batteries through in situ chemical oxidative polymerization. The introduction of PR nanoflakes not only inhibits the degradation of PANI and generates more active sites for Zn2+ storage but also enables a synergistic effect of the Zn2+ insertion/extraction and P-Zn alloying reaction. This promotes a high reversible specific capacity of 240.2 mAh g-1 at 0.2 A g-1 and excellent rate performance for the PR/PANI nanocomposite cathode material. Compared to the pristine PANI cathode material, the PR/PANI nanocomposite cathode material is more suitable for the Zn-PANI battery, thanks to its higher specific capacity and better cycle stability. This study provides an innovative approach for developing the next generation of reliable PR-based electrode materials for aqueous energy-storage devices.

16.
Sci Bull (Beijing) ; 69(6): 741-746, 2024 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-38320899

RESUMEN

Several Pulsar Timing Array (PTA) Collaborations have recently provided strong evidence for a nHz Stochastic Gravitational-Wave Background (SGWB). Here we investigate the implications of a first-order phase transition occurring within the early Universe's dark quantum chromodynamics epoch, specifically within the framework of the mirror twin Higgs dark sector model. Our analysis indicates a distinguishable SGWB signal originating from this phase transition, which can explain the measurements obtained by PTAs. Remarkably, a significant portion of the parameter space for the SGWB signal also effectively resolves the existing tensions in both the H0 and S8 measurements in Cosmology. This intriguing correlation suggests a possible common origin of these three phenomena for 0.2<ΔNeff<0.5, where the mirror dark matter component constitutes less than 30% of the total dark matter abundance. Next-generation CMB experiments such as CMB-S4 can test this parameter region.

17.
Sci Total Environ ; 937: 173504, 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-38797411

RESUMEN

Studying the relationship between biodiversity and ecosystem multifunctionality (the ability of ecosystems to provide multiple ecosystem functions) (BEMF) is a current hotspot in ecology research. Previous studies on BEMF emphasized the role of plant and microbial diversity but rarely mention stand spatial structure. To investigate the effect of stand spatial structure on BEMF, this study established 30 forest dynamic plots in three natural restoration stages (shrubbery, secondary growth forest, and old-growth forest) in Maolan National Nature Reserve, Guizhou province, China. A positive response in soil multifunctionality (SMF), plant species diversity, stand spatial structure, and fungal ß diversity (p < 0.05) followed natural restoration. However, bacterial ß diversity showed a negative response (p < 0.05), while microbial α diversity remained unchanged (p > 0.05). These results based on a structural equation model showed that plant species diversity had no direct or indirect effect on SMF, soil microbial diversity was the only direct driver of SMF, and stand spatial structure indirectly affected SMF through soil microbial diversity. The random forest model showed that soil microbial ß diversity and the Shannon-Wiener index of the diameter at breast height for woody plant species were the optimal variables to characterize SMF and soil microbial diversity, respectively. These results suggested that natural restoration promoted SMF, and microbial diversity had a direct positive effect on SMF. In the meantime, stand spatial structure had a significant indirect effect on SMF, while plant species diversity did not. Future work on degraded karst forest restoration should direct more attention to the role of the stand spatial structure and emphasize the importance of biodiversity.


Asunto(s)
Biodiversidad , Bosques , Microbiología del Suelo , Suelo , China , Suelo/química , Microbiota , Ecosistema , Hongos , Monitoreo del Ambiente , Conservación de los Recursos Naturales
18.
Light Sci Appl ; 13(1): 159, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38982066

RESUMEN

Ultrasound sensors play an important role in biomedical imaging, industrial nondestructive inspection, etc. Traditional ultrasound sensors that use piezoelectric transducers face limitations in sensitivity and spatial resolution when miniaturized, with typical sizes at the millimeter to centimeter scale. To overcome these challenges, optical ultrasound sensors have emerged as a promising alternative, offering both high sensitivity and spatial resolution. In particular, ultrasound sensors utilizing high-quality factor (Q) optical microcavities have achieved unprecedented performance in terms of sensitivity and bandwidth, while also enabling mass production on silicon chips. In this review, we focus on recent advances in ultrasound sensing applications using three types of optical microcavities: Fabry-Perot cavities, π-phase-shifted Bragg gratings, and whispering gallery mode microcavities. We provide an overview of the ultrasound sensing mechanisms employed by these microcavities and discuss the key parameters for optimizing ultrasound sensors. Furthermore, we survey recent advances in ultrasound sensing using these microcavity-based approaches, highlighting their applications in diverse detection scenarios, such as photoacoustic imaging, ranging, and particle detection. The goal of this review is to provide a comprehensive understanding of the latest advances in ultrasound sensing with optical microcavities and their potential for future development in high-performance ultrasound imaging and sensing technologies.

19.
J Colloid Interface Sci ; 672: 465-476, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-38852349

RESUMEN

Enhancing the flame retardancy of epoxy (EP) resins typically entailed a trade-off with other physical properties. Herein, hyperbranched poly(amidoamine) (HPAA) and phytic acid (PA) were used to functionalize graphene oxide (GO) via electrostatic self-assembly in water to prepare a phosphorus-nitrogen functionalized graphene oxide nanosheet (PN-GOs), which could be utilized as high efficient flame-retardant additive of epoxy resin without sacrificing other properties. The PN-GOs demonstrated improved dispersion and compatibility within the EP matrix, which resulted in significant concurrent enhancements in both the mechanical performance and flame-retardant properties of the PN-GOs/EP nanocomposites over virgin EP. Notably, the incorporation of just 1.0 wt% PN-GOs yielded a 20.4, 6.4 and 42.7 % increases in flexural strength, flexural modulus and impact strength for the PN-GOs/EP nanocomposites, respectively. Furthermore, simultaneous reductions were achieved in the peak heat release rate (pHRR) by 60.0 %, total smoke production (TSP) by 43.0 %, peak CO production rate (pCOP) by 57.9 %, and peak CO2 production rate (pCO2P) by 63.9 %. This study presented a facile method for the design of GO-based nano flame retardants, expanding their application potential in polymer-matrix composites.

20.
Materials (Basel) ; 16(18)2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37763464

RESUMEN

The automated fiber placement (AFP) process faces a crucial challenge: the emergence of out-of-plane buckling in thermoplastic prepreg tows during steering, significantly impeding the quality of composite layup. In response, this study introduces a novel approach: the development of equations for wrinkle-free fiber placement within composite pressure vessels. The investigation encompasses a detailed analysis of prepreg trajectories in relation to shell geometry, accompanied by an in-depth understanding of the underlying causes of wrinkling on dome surfaces. Moreover, a comprehensive model for shell coverage, grounded in placement parameters, is meticulously established. To validate the approach, a simulation tool is devised to calculate press roller motions, ensuring the uniform fiber dispersion on the mandrel and achieving flawless coverage of the shell without wrinkles. This innovative strategy not only optimizes the AFP process for composite layup but also remarkably enhances the overall quality of composite shells. As such, this research carries significant implications for the advancement of composite manufacturing techniques and the concurrent improvement in material performance.

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