Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
ACS Appl Mater Interfaces ; 16(37): 49733-49744, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39231365

RESUMO

This paper presents a comprehensive study of the structural optimization of polyimide-film (PI-film) capacitive humidity sensors, with a focus on enhancing their performance for application in new energy vehicles (NEVs). Given the critical role of humidity sensors in ensuring the safety and efficiency of vehicle operations─particularly in monitoring lithium-ion battery systems─the study explores the intricate relationship between the interdigitated electrode (IDE) dimensions and the PI-film thickness to optimize sensor responsiveness and reliability. Through a combination of COMSOL Multiphysics simulations (a powerful finite element analysis, solver, and simulation software) and experimental validation, the research identifies the optimal geometrical combination that maximizes the sensitivity and minimizes the response time. The fabrication process is streamlined for batch preparation, leveraging the spin-coating process to achieve consistent and reliable PI films. Extensive characterizations confirm the superior morphology, chemical composition, and humidity-sensing capabilities of the developed sensors. Practical performance tests further validate their exceptional repeatability, long-term stability, low hysteresis, and excellent selectivity, underpinning their suitability for automotive applications. The final explanation of the sensing mechanism provides a solid theoretical foundation for observed performance improvements. This work not only advances the field of humidity sensing for vehicle safety but also offers a robust theoretical and practical framework for the batch preparation of PI-film humidity sensors, promising enhanced safety and reliability for NEVs.

2.
Nervenarzt ; 95(9): 824-829, 2024 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-39085520

RESUMO

BACKGROUND: Kratom/ketum is a psychoactive herbal preparation that has been used for a long time as a remedy and performance-enhancing substance in Southeast Asia. The advancement of globalization is making kratom increasingly more available in the western world, where it is becoming increasingly more used. OBJECTIVE: The current research on kratom and its ingredients is presented. MATERIAL AND METHODS: An overview of the use and effects of kratom is exemplary given on the basis of reports. The instrumentalization of the drug and its consequences up to the development of addiction are discussed. RESULTS: Consumption is accompanied by several instrumentalizeable effects so that kratom is used as a therapeutic substance in the self-management of pain, anxiety and depression as well as other substance addictions. Another benefit comes from the performance-enhancing effects on physical work and in a social context. Consumption is usually well controlled, rarely escalates and has few and mostly mild aversive side effects. The danger arises from consumption particularly when there is an escalation of the dose and from mixed consumption with other psychoactive substances. The main alkaloid mitragynine and the more potent 7­hydroxy-mitragynine are considered mainly responsible for the effect. Both have a complex pharmacology that involves partial µ­opioid receptor agonism. DISCUSSION: Epidemiological, clinical and neurochemical studies have shown that kratom only has a limited addictive drug profile, which might suggest a medical use as a remedy or substitute in addiction treatment.


Assuntos
Mitragyna , Transtornos Relacionados ao Uso de Substâncias , Humanos , Mitragyna/química , Extratos Vegetais/uso terapêutico , Alcaloides de Triptamina e Secologanina/uso terapêutico , Alcaloides de Triptamina e Secologanina/farmacologia , Fitoterapia
3.
ChemSusChem ; 17(14): e202400466, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-38727153

RESUMO

As a result of full-scale ongoing global efforts, the power conversion efficiency (PCE) of the organic-inorganic metal halide perovskite has skyrocketed. Unfortunately, the long-term operational stability for commercialization standards is still lagging owing to intrinsic defects such as ion migration-induced degradation, undercoordinated Pb2+, and shallow defects initiated by disordered crystal growth. Herein, we employed multifunctional, non-volatile tetra-methyl guanidine hydrochloride [TMGHCL] ionic liquid (IL) as an additive to elucidate defects' passivation effects on organic-inorganic metal halide perovskite. More specifically, the formation of hydrogen bonds between H+ in GA+ and I- and coordinate bonding between Cl- and undercoordinated Pb2+ could significantly passivate these defects. The hypothesis was confirmed by both experimental and DFT simulations displaying that the optimized ratio of IL integration restrains ion migration, improving grains' size, and significantly elongating the carrier lifetime. Remarkably, the modified cell achieved a peak efficiency of 22.00 % with negligible hysteresis, compared to the control device's PCE of 20.12 %. In addition, the TMGHCL-based device retains its 93.29 % efficiency after 16 days of continuous exposure to air with a relative humidity of 35±5% and temperature of 25±5 °C. This efficient approach of adding IL to perovskites absorber can produce high PCE and has strong commercialization potential.

4.
Sci Total Environ ; 931: 172973, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38705294

RESUMO

In this work, corn straw was used as raw material, Hummers method and activation were used to adjust the graphite structure in biochar, and preparing straw based biochar (H-BCS) with ultra-high specific surface area (3441.80 m2/g), highly total pore volume (1.9859 cm3/g), and further enhanced physicochemical properties. Compared with untreated straw biochar (BCS), the specific surface area and total pore volume of H-BCS were increased by 47.24 % and 55.85 %, respectively. H-BCS showed good removal ability in subsequent experiments by using chloramphenicol (CP), hexavalent chromium (Cr6+), and crystal violet (CV) as adsorption models. In addition, the adsorption capacities of H-BCS (CP: 1396.30 mg/g, Cr6+: 218.40 mg/g, and CV: 1246.24 mg/g) are not only higher than most adsorbents, even after undergoing 5 cycles of regeneration, its adsorption capacity remains above 80 %, indicating significant potential for practical applications. In addition, we also speculated and analyzed the conjecture about the "graphite-structure regulation" during the preparation process, and finally discussed the possible mechanism during the adsorption processes. We hope this work could provide a new strategy to solve the restriction of biochar performance by further exploring the regulation of graphite structure in carbon materials.


Assuntos
Carvão Vegetal , Grafite , Poluentes Químicos da Água , Carvão Vegetal/química , Grafite/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Adsorção , Eliminação de Resíduos Líquidos/métodos , Cromo/química , Poluição da Água/prevenção & controle , Zea mays/química , Purificação da Água/métodos
5.
Appl Neuropsychol Child ; : 1-8, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38452103

RESUMO

The present study aimed to identify autistic traits as a mediator between visual working memory capacity and enhanced performance in visual-perceptual tasks in children with ASD. One hundred-forty children, ages 4-6 years, participated in this study (mean age = 5.34 ± 4.11, 98 males). They were recruited from Taiba Specialized Centers for the Care of People with Special Needs in Saudi Arabia. A correlational design was used to identify the mediating role of autistic traits in the relationship between visual working memory capacity and enhanced performance in visual-perceptual tasks in children with ASD. The present study developed a theoretical model that incorporated autistic traits as a mediator between visual working memory capacity and enhanced performance in visual-perceptual tasks in children with ASD. The study findings indicate that: (1) A significant positive correlation exists between autistic traits and visual working memory capacity; (2) A significant positive correlation exists between autistic traits and enhanced performance in visual-perceptual tasks; (3) The relationship between visual working memory capacity and enhanced performance is mediated by autistic traits.

6.
Front Neurosci ; 17: 1110714, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37123379

RESUMO

While noise is generally believed to impair performance, the detection of weak stimuli can sometimes be enhanced by introducing optimum noise levels. This phenomenon is termed 'Stochastic Resonance' (SR). Past evidence suggests that autistic individuals exhibit higher neural noise than neurotypical individuals. It has been proposed that the enhanced performance in Autism Spectrum Disorder (ASD) on some tasks could be due to SR. Here we present a computational model, lab-based, and online visual identification experiments to find corroborating evidence for this hypothesis in individuals without a formal ASD diagnosis. Our modeling predicts that artificially increasing noise results in SR for individuals with low internal noise (e.g., neurotypical), however not for those with higher internal noise (e.g., autistic, or neurotypical individuals with higher autistic traits). It also predicts that at low stimulus noise, individuals with higher internal noise outperform those with lower internal noise. We tested these predictions using visual identification tasks among participants from the general population with autistic traits measured by the Autism-Spectrum Quotient (AQ). While all participants showed SR in the lab-based experiment, this did not support our model strongly. In the online experiment, significant SR was not found, however participants with higher AQ scores outperformed those with lower AQ scores at low stimulus noise levels, which is consistent with our modeling. In conclusion, our study is the first to investigate the link between SR and superior performance by those with ASD-related traits, and reports limited evidence to support the high neural noise/SR hypothesis.

7.
Nanomaterials (Basel) ; 13(5)2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36903738

RESUMO

In this study we fabricated a piezoelectric nanogenerator (PENG) of nanocomposite thin film comprising a conductive nanofiller of reduced graphene oxide (rGO) dispersed in a poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) matrix that was anticipated to show enhanced energy harvest performance. For the film preparation we employed the Langmuir-Schaefer (LS) technique to provide direct nucleation of the polar ß-phase without any traditional polling or annealing process. We prepared five PENGs consisting of the nanocomposite LS films with different rGO contents in the P(VDF-TrFE) matrix and optimized their energy harvest performance. We found that the rGO-0.002 wt% film yielded the highest peak-peak open-circuit voltage (VOC) of 88 V upon bending and releasing at 2.5 Hz frequency, which was more than two times higher than the pristine P(VDF-TrFE) film. This optimized performance was explained by increased ß-phase content, crystallinity, and piezoelectric modulus, and improved dielectric properties, based on scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), x-ray diffraction (XRD), piezoelectric modulus, and dielectric property measurement results. This PENG with enhanced energy harvest performance has great potential in practical applications for low energy power supply in microelectronics such as wearable devices.

8.
Int J Mol Sci ; 23(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36430558

RESUMO

In this study, Irisensata Thunb grass (ITG) was used as a biomass carbon resource to prepare biochars for the first time. After microbial treatment, the obtained microbial-treated ITG (MITG) was activated by using a mixed base as an activator for preparation of biochar (MITGB). The specific surface area and total pore volume of MITGB were 3036.4 m2/g and 1.5252 cm3/g, which were higher than those of biochar prepared without microbial treatment (ITGB, 2930.0 m2/g and 1.5062 cm3/g). Besides, the physicochemical properties of MITGB and ITGB were also quite different including micro morphology, surface chemistry, functional groups, etc. In the experiment of removing organic pollutants with synthetic dye RhB and antibiotic TH as the models, MITGB showed excellent treatment ability. The maximum adsorption capacities of MITGB for RhB and TH were 1354.2 and 1462.6 mg/g, which were higher than most of the biochars. In addition, after five cycles of recycling, the adsorption capacities of the organic pollutant models can still be maintained at more than 80%, which showed high stability. This work verified the feasibility of microbial treatment to further improve the performance of biochar and provided a new idea and direction for exploring other biochars.


Assuntos
Poluentes Ambientais , Porosidade , Carvão Vegetal/química , Adsorção
9.
Molecules ; 27(20)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36296719

RESUMO

Sulfonic resins are highly efficient cation exchangers widely used for metal removal from aqueous solutions. Herein, a new sulfonation process is designed for the sulfonation of algal/PEI composite (A*PEI, by reaction with 2-propylene-1-sulfonic acid and hydroxylamine-O-sulfonic acid). The new sulfonated functionalized sorbent (SA*PEI) is successfully tested in batch systems for strontium recovery first in synthetic solutions before investigating with multi-component solutions and final validation with seawater samples. The chemical modification of A*PEI triples the sorption capacity for Sr(II) at pH 4 with a removal rate of up to 7% and 58% for A*PEI and SA*PEI, respectively (with SD: 0.67 g L-1). FTIR shows the strong contribution of sulfonate groups for the functionalized sorbent (in addition to amine and carboxylic groups from the support). The sorption is endothermic (increase in sorption with temperature). The sulfonation improves thermal stability and slightly enhances textural properties. This may explain the fast kinetics (which are controlled by the pseudo-first-order rate equation). The sulfonated sorbent shows a remarkable preference for Sr(II) over competitor mono-, di-, and tri-valent metal cations. Sorption properties are weakly influenced by the excess of NaCl; this can explain the outstanding sorption properties in the treatment of seawater samples. In addition, the sulfonated sorbent shows excellent stability at recycling (for at least 5 cycles), with a loss in capacity of around 2.2%. These preliminary results show the remarkable efficiency of the sorbent for Sr(II) removal from complex solutions (this could open perspectives for the treatment of contaminated seawater samples).


Assuntos
Poluentes Químicos da Água , Adsorção , Poluentes Químicos da Água/química , Cloreto de Sódio , Água do Mar , Água , Cinética , Estrôncio , Ácidos Sulfônicos , Aminas , Concentração de Íons de Hidrogênio
10.
Chemosphere ; 273: 129748, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33524751

RESUMO

NaTaO3 (NTO), as a popular photocatalyst with the prominent redox ability, largely straddles across the conduction band minimum (CBM) and valence band maximum (VBM) edge over Fermi level. Pristine NTO exhibits the poor light-harvesting ability and the rapid recombination of electron-hole pairs. We proposed an effective method to improve the photocatalytic property of NTO (ABO3-type) by substituting B site with Sr. The SrxNaTayO3 (SNTO) exhibited the boosted photocatalytic activity toward tetracycline oxidation under solar light irradiation. The rate constant for S0.5NTO (molar ratio of Sr: Ta = 1 : 2) was 5.1 times higher than the pure NTO. DFT results indicated that the Sr 3d orbital combining the O 2p and Ta 5d hybrid orbitals, widened the VB of SNTO. The band gap was narrowed from 3.86 to 2.82 eV after Sr substitution, which enhanced its light-harvesting ability. The VBM moved upward for 1.42 V and the CBM moved upward for 0.38 V. The shifts of the CBM and VBM, together with the more stretched Ta-O-Ta configuration, highly facilitated the electron-hole pair separation in SNTO. These electronic structure changes accounted for the significant photocatalytic performance enhancement of NaTaO3 via Sr substitution for B-site-Ta.


Assuntos
Luz , Semicondutores , Catálise , Eletrônica , Elétrons
11.
Angew Chem Int Ed Engl ; 60(13): 7056-7060, 2021 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-33443304

RESUMO

The co-insertion of dual ions can often offer enhanced electrochemical performance for the aqueous zinc batteries. Although the insertion of non-metallic ions has been achieved in aqueous zinc batteries, the co-insertion chemistry of non-metallic cations is still a challenge. Here, a reversible H+ /NH4 + co-insertion/extraction mechanism was developed in an aqueous Zn/MnO2 battery system. The synergistic effect between the dual cations endows the aqueous batteries with the fast kinetics of ion diffusion and the reversible structure evolution of MnO2 . As a result, the Zn/MnO2 battery displays excellent rate capability and cycling performance. This work will pave the way toward the design of aqueous rechargeable batteries with non-metallic ions.

12.
Chemosphere ; 243: 125300, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31734595

RESUMO

The removal of nutrients in a combined modified University of Cape Town and post-anoxic/aerobic-membrane bioreactor (UCT-A/MBR) was investigated. Denitrifying phosphorus removal (DPR) and nitrate-dependent anaerobic ferrous oxidation (NAFO) were applied to enhance the nutrient removal performances. The results showed that NAFO with the addition of Fe(II) and DPR could promote nitrogen and phosphorus removal. The total nitrogen removal efficiency gradually increased from 71.05 ±â€¯2.00% to 73.84 ±â€¯1.74% and 75.70 ±â€¯1.47% with no Fe(II) addition, addition to the post-anoxic tank, and addition to the anoxic tank, and the total phosphorus removal efficiency increased from 89.37 ±â€¯1.91% to 95.21 ±â€¯0.85% and 96.01 ±â€¯1.10%, respectively. Gene sequencing was conducted, and Saprospiraceae was determined to be the dominant DPR-related bacteria, with its abundance increasing from 16.31% to 22.45% after Fe(II) addition. Additionally, the proportion of the NAFO-related bacteria Azospira increased from 0.58% to 1.91% after Fe(II) addition. The microbial succession caused by the addition of Fe(II) may have resulted in the enhanced removal performance.


Assuntos
Reatores Biológicos/normas , Desnitrificação , Compostos Ferrosos/farmacologia , Nutrientes/isolamento & purificação , Fósforo/isolamento & purificação , Bactérias/efeitos dos fármacos , Reatores Biológicos/microbiologia , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos
13.
ACS Appl Mater Interfaces ; 11(34): 30943-30952, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31364840

RESUMO

Owing to its electronic conductivity and electrochemical reactivity, polyaniline (PANI) can serve as the cathode for rechargeable zinc-ion batteries (ZIBs). However, it suffers from fast deactivation and thus performance deterioration because of spontaneous deprotonation during charge/discharge. Here, we report an effective strategy to improve the electrochemical reactivity and stability of the PANI-based cathode by constructing a π-electron conjugated system between PANI and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on carbon nanotubes (CNTs). The impressive performance of the post-treated CNTs-PANI-PEDOT:PSS (t-CNTs-PA-PE) cathode is largely attributed to the -SO3-H+ groups in PSS, which acts as an internal proton reservoir and provides enough H+ for PANI's protonation, thus promoting its electrochemical activity and reversibility. Besides, the strong interactions between PANI and PEDOT:PSS assist the stretching of π-π conjugation chains, bringing about enhanced electronic conductivity. Consequently, the t-CNTs-PA-PE cathode achieves a high capacity of 238 mA h g-1, together with good rate capability and long-term stability (over 1500 cycles with 100% Coulombic efficiency). Through exerting the freestanding t-CNTs-PA-PE, a flexible ZIB was further constructed with both outstanding electrochemical properties and superior high safety. This work demonstrates the availability of conducting polymer cathodes for high-performance ZIBs, fulfilling the need of flexible electronics.

14.
ACS Appl Mater Interfaces ; 10(38): 32192-32200, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30178659

RESUMO

Carbonized wood (CW) achieved by the pyrolysis of various nature woods has received ever-increasing attentions in energy storage and conversion. However, its charge storage capacity is rather low because of its intrinsic ion adsorption mechanism. This work reports the enhanced capacitive performance of CW by growing electroactive FeOOH nanosheets and coating conductive poly(3,4-ethylenedioxythiophene) (PEDOT) network. Those vertically grown FeOOH nanosheets on both the external surface and inside the channel of CW offer more opened active sites for Faradaic reactions, whereas the porous and conductive PEDOT network significantly boosts the electrode conductivity, facilitates the ion transport, and protects the FeOOH sheets from destruction during cycling. Accordingly, the CW-FeOOH-PEDOT ternary electrodes exhibit 4.3 times higher volumetric capacitance than the CW electrode and remain at 90% capacitance upon increasing the current density from 10 to 50 mA cm-2. Remarkably, the electrode maintains 103% of its capacitance even after 10 000 cycles of galvanostatic charge-discharge at 200 mA cm-2. Besides these unique electrochemical behaviors, the CW-FeOOH-PEDOT also preserves good mechanical strength of the pristine CW electrode. This property allows easy processing of CW-based electrodes into robust energy storage device for practical applications.

15.
ACS Appl Mater Interfaces ; 10(7): 6309-6316, 2018 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-29384645

RESUMO

Li2MnSiO4 has attracted significant attention as a cathode material for lithium ion batteries because of its high theoretical capacity (330 mA h g-1 with two Li+ ions per formula unit), low cost, and environmentally friendly nature. However, its intrinsically poor Li diffusion, low electronic conductivity, and structural instability preclude its use in practical applications. Herein, elongated hexagonal prism-shaped Li2MnSiO4 nanoplates with preferentially exposed {001} and {210} facets have been successfully synthesized via a solvothermal method. Density functional theory calculations and experimental characterization reveal that the formation mechanism involves the decomposition of solid precursors to nanosheets, self-assembly into nanoplates, and Ostwald ripening. Hydroxyl-containing solvents such as ethylene glycol and diethylene glycol play a crucial role as capping agents in tuning the preferential growth. Li2MnSiO4@C nanoplates demonstrate a near theoretical discharge capacity of 326.7 mA h g-1 at 0.05 C (1 C = 160 mA h g-1), superior rate capability, and good cycling stability. The enhanced electrochemical performance is ascribed to the electrochemically active {001} and {210} exposed facets, which provide short and fast Li+ diffusion pathways along the [001] and [100] axes, a conformal carbon nanocoating, and a nanoscaled platelike structure, which offers a large electrode/electrolyte contact interface for Li+ extraction/insertion processes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA