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1.
PLoS One ; 19(3): e0298401, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38512896

RESUMO

Researchers conducted an investigation by tornado simulator to study the impact of wind angle on the aerodynamic characteristics of a reduced (1:150) high-speed train model using six-dimensional force/torque sensor. The reduced scale model size can match the relative size relationship between high-speed train and tornado vortex core in real condition. Results show that the wind angle affects the mean value and standard deviation of the force and moment coefficient of the high-speed train at the same radial position. The variations of the mean value and standard deviation of the pitching moment coefficient of the high-speed train carriage model at 60°and 90°are different from that at other wind angles. The variations of the mean value of the pitching moment coefficient of the high-speed train head model at 0°, 15°and 30°are different from that at other wind angles. The variations of the standard deviation of the pitching moment coefficient of the high-speed train head model at 60°,75°and 90°are different from that at other wind angles. This research will help the further study of the operation safety of high-speed train in the event of a tornado impacting a high-speed train network.


Assuntos
Tornados , Vento , Torque
2.
Carbohydr Polym ; 332: 121935, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38431402

RESUMO

A novel cellulose composite (denoted as PEI@MMA-1) with porous interconnected structure was prepared by adsorbing methyl cellulose (MC) onto microcrystalline cellulose (MCC) and cross-linking polyethyleneimine (PEI) with MCC by the action of epichlorohydrin, which had the excellent adsorption property, wettability and elasticity. The performances of PEI@MMA-1 composite for removing tetracycline (TC), Cu2+ and coexistent pollutant (TC and Cu2+ mixture) were systematically explored. For single TC or Cu2+ contaminant, the maximum adsorption capacities were 75.53 and 562.23 mg/g at 30 °C, respectively, while in the dual contaminant system, they would form complexes and Cu2+ could play a "bridge" role to remarkably promote the adsorption of TC with the maximum adsorption capacities of 281.66 and 253.58 mg/g for TC and Cu2+. In addition, the adsorption kinetics, isotherms and adsorption mechanisms of single-pollutant and dual-pollutant systems have been thoroughly investigated. Theoretical calculations indicated that the amide group of TC molecule with the assistance of Cu2+ interacted with the hydroxyl group of PEI@MMA-1 composite to enhance the TC adsorption capacity. Cycle regeneration and fixed bed column experiments revealed that the PEI@MMA-1 possessed the excellent stability and utility. Current PEI@MMA-1 cellulose composite exhibited a promising application for remediation of heavy metals and antibiotics coexistence wastewater.


Assuntos
Celulose/análogos & derivados , Cobre , Polietilenoimina/análogos & derivados , Poluentes Químicos da Água , Cobre/química , Adsorção , Poluentes Químicos da Água/química , Tetraciclina/química , Antibacterianos , Íons , Cinética
3.
J Colloid Interface Sci ; 638: 412-426, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36758254

RESUMO

The strong electron interaction between metal oxide-carbon-based catalyst components plays a vital role in the peroxymonosulfate (PMS) activation for pollutant degradation. Herein, a novel CoOOH nanosheets anchored on rape straw-derived biochar (BC) surface (labeled as CoOOH/BC) as an efficient PMS activator toward degrading sulfamethoxazole (SMX) was synthesized. Experimental results indicated that integrating CoOOH nanosheets on the BC surface could inhibit CoOOH aggregation to increase the specific surface areas, exert a component synergistic effect to enhance activation degradation activity, and improve the catalyst stability. As a result, a 96 % degradation efficiency of SMX was achieved within 20 min over 20 wt% CoOOH/BC composite catalyst under the optimal conditions. Density functional theory (DFT) calculations disclosed that a built-in electric field (BIEF) pointing from BC to CoOOH was constructed at their interface, which could mediate PMS activation for reactive oxygen species (ROS) generation and induce direct electron transfer from SMX to PMS, resulting in efficient SMX degradation via both radical and non-radical pathways. Moreover, quenching experiments and electron paramagnetic resonance (EPR) measurements confirmed that single oxide (1O2) and superoxide radical (O2·-) are the dominant active species in the current system. Additionally, the possible SMX degradation routes were reasonably proposed based on liquid chromatography-mass spectrometry (LC-MS) results. This work provides an in-depth understanding of the role of BIEF in PMS activation, and expands the application of biochar-based materials in the field of environmental remediation.


Assuntos
Carvão Vegetal , Peróxidos , Peróxidos/química , Sulfametoxazol/química
4.
Sensors (Basel) ; 23(4)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36850406

RESUMO

In order to improve the performance of a micro-electro-mechanical system (MEMS) accelerometer, three algorithms for compensating its temperature drift are proposed in this paper, including deep long short-term memory recurrent neural network (DLSTM-RNN, short DLSTM), DLSTM based on sparrow search algorithm (SSA), and DLSTM based on improved SSA (ISSA). Moreover, the piecewise linear approximation (PLA) method is employed in this paper as a comparison to evaluate the impact of the proposed algorithm. First, a temperature experiment is performed to obtain the MEMS accelerometer's temperature drift output (TDO). Then, we propose a real-time compensation model and a linear approximation model for neural network methods compensation and PLA method compensation, respectively. The real-time compensation model is a recursive method based on the TDO at the last moment. The linear approximation model considers the MEMS accelerometer's temperature and TDO as input and output, respectively. Next, the TDO is analyzed and optimized by the real-time compensation model and the three algorithms mentioned before. Moreover, the TDO is also compensated by the linear approximation model and PLA method as a comparison. The compensation results show that the three neural network methods and the PLA method effectively compensate for the temperature drift of the MEMS accelerometer, and the DLSTM + ISSA method achieves the best compensation effect. After compensation by DLSTM + ISSA, the three Allen variance coefficients of the MEMS accelerometer that bias instability, rate random walk, and rate ramp are improved from 5.43×10-4mg, 4.33×10-5mg/s12, 1.18×10-6mg/s to 2.77×10-5mg, 1.14×10-6mg/s12, 2.63×10-8mg/s, respectively, with an increase of 96.68% on average.

5.
Int J Biol Sci ; 18(1): 441-458, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34975343

RESUMO

Traumatic brain injury (TBI) is one of the main concerns worldwide as there is still no comprehensive therapeutic intervention. Astrocytic water channel aquaporin-4 (AQP-4) system is closely related to the brain edema, water transport at blood-brain barrier (BBB) and astrocyte function in the central nervous system (CNS). Minocycline, a broad-spectrum semisynthetic tetracycline antibiotic, has shown anti-inflammation, anti-apoptotic, vascular protection and neuroprotective effects on TBI models. Here, we tried to further explore the underlying mechanism of minocycline treatment for TBI, especially the relationship of minocycline and AQP4 during TBI treatment. In present study, we observed that minocycline efficaciously reduces the elevation of AQP4 in TBI mice. Furthermore, minocycline significantly reduced neuronal apoptosis, ameliorated brain edema and BBB disruption after TBI. In addition, the expressions of tight junction protein and astrocyte morphology alteration were optimized by minocycline administration. Similar results were found after treating with TGN-020 (an inhibitor of AQP4) in TBI mice. Moreover, these effects were reversed by cyanamide (CYA) treatment, which notably upregulated AQP4 expression level in vivo. In primary cultured astrocytes, small-interfering RNA (siRNA) AQP4 treatment prevented glutamate-induced astrocyte swelling. To sum up, our study suggests that minocycline improves the functional recovery of TBI through reducing AQP4 level to optimize BBB integrity and astrocyte function, and highlights that the AQP4 may be an important therapeutic target during minocycline treating for TBI.


Assuntos
Aquaporina 4/efeitos dos fármacos , Edema Encefálico/tratamento farmacológico , Lesões Encefálicas Traumáticas/tratamento farmacológico , Minociclina/farmacologia , Animais , Antibacterianos/farmacologia , Apoptose , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Recuperação de Função Fisiológica
6.
Front Surg ; 9: 1043794, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36684344

RESUMO

Objective: To observe and analyze the surgical efficacy of arthroscopic debridement of calcified deposits and arthroscopic debridement combined with subacromial decompression in patients with supraspinatus tendon calcific myositis. To observe the effect of Subacromial decompression on the efficacy of arthroscopic treatment of shoulder calcific tendinitis. Patients and methods: From 2016 to 2021, 48 cases of shoulder arthroscopic debridement due to supraspinatus calcific tendinitis met the inclusion criteria and were included, with 24 cases assigned to the arthroscopic debridement group and 24 cases to the arthroscopic debridement combined with subacromial decompression group. Changes between preoperative and postoperative shoulder pain and shoulder function were statistically analyzed. Results: The 24 patients in the arthroscopic debridement group were better than the arthroscopic debridement combined with subacromial decompression group in terms of short-term postoperative shoulder pain and shoulder joint function recovery (P < 0.05). There was no significant difference in the postoperative long-term shoulder pain and shoulder function recovery between the two groups (P > 0.05). Conclusions: Compared with arthroscopic debridement combined with subacromial decompression, arthroscopic debridement alone is a better surgical option for the treatment of calcific tendinitis.

7.
Lab Invest ; 102(1): 90-101, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34521991

RESUMO

Bioactive glass (BG) has recently shown great promise in soft tissue repair, especially in wound healing; however, the underlying mechanism remains unclear. Pyroptosis is a novel type of programmed cell death that is involved in various traumatic injury diseases. Here, we hypothesized that BG may promote wound healing through suppression of pyroptosis. To test this scenario, we investigated the possible effect of BG on pyroptosis in wound healing both in vivo and in vitro. This study showed that BG can accelerate wound closure, granulation formation, collagen deposition, and angiogenesis. Moreover, western blot analysis and immunofluorescence staining revealed that BG inhibited the expression of pyroptosis-related proteins in vivo and in vitro. In addition, while BG regulated the expression of connexin43 (Cx43), it inhibited reactive oxygen species (ROS) production. Cx43 activation and inhibition experiments further indicate that BG inhibited pyroptosis in endothelial cells by decreasing Cx43 expression and ROS levels. Taken together, these studies suggest that BG promotes wound healing by inhibiting pyroptosis via Cx43/ROS signaling pathway.


Assuntos
Cerâmica/farmacologia , Conexina 43/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Piroptose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Vasos Sanguíneos/efeitos dos fármacos , Vasos Sanguíneos/fisiologia , Western Blotting , Cerâmica/química , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Masculino , Camundongos Endogâmicos ICR , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Polymers (Basel) ; 13(20)2021 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-34685223

RESUMO

Rice straw-derived cellulose (RSC) with purity of 92 wt.% was successfully extracted from rice straw by a novel and facile strategy, which integrated the C2H5OH/H2O autocatalytic process, dilute alkali treatment and H2O2 bleaching process. Influencing factors of the cellulose extraction were systematically examined, such as ethanol concentration, alkali concentration, H2O2 bleaching process and so on; the optimal extraction conditions of cellulose was determined. A series of rice straw-derived cellulose acetate (RSCA) with different degree of substitution (DS) were prepared by the acetylation reaction; the effects of Ac2O/cellulose ratio, reaction temperature and reaction time on the acetylation reaction were investigated. Results of FTIR and XRD analysis demonstrated that highly purified RSC and RSCA were prepared comparing with the commercial cellulose and cellulose acetate. Solubility analysis of RSCA with different DS indicated as-prepared RSCA with DS of 2.82 possessed the best solubleness, which was suitable for electrospinning. Moreover, the flexible RSCA fibrous membrane was easily fabricated by a facile electrospinning method. Our proposed method provided a strategy for realizing the high-value utilization of waste rice straw resource, as prepared RSC and RSCA can be used as chemical raw material, and electrospun RSCA fibrous membrane has various applications in medical materials, food packaging, water purification and so on.

9.
Front Pharmacol ; 12: 628950, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34497508

RESUMO

Diabetic nephropathy (DN) is a common diabetes associated complication. Thus, it is important to understand the pathological mechanism of DN and find the appropriate therapeutic strategy for it. Dl-3-n-Butylphthalide (DL-NBP) has anti-inflammatory and antioxidant effects, and been widely used for the treatment of stroke and cardiovascular diseases. In this study, we selected three different doses (20, 60, and 120 mg⋅kg-1 d-1) of DL-NBP and attempted to elucidate its role and molecular mechanism underlying DN. We found that DL-NBP, especially at the dose of 60 or 120 mg⋅kg-1 d-1, could significantly ameliorate diabetes-induced elevated blood urea nitrogen (BUN) and creatinine level, and alleviate renal fibrosis. Additionally, the elevated expressions of collagen and α-smooth muscle actin (α-SMA) in the kidney from db/db mice were found to be significantly suppressed after DL-NBP treatment. Furthermore, mechanistic studies revealed that DL-NBP inhibits pro-inflammatory cytokine levels, thereby ameliorating the development of renal fibrosis. Moreover, we found that DL-NBP could not only reduce the endoplasmic reticulum stress (ERS), but also suppress activation of the renin-angiotensin system to inhibit vascular endothelial growth factor (VEGF) level, which subsequently reduces the podocyte apoptosis in kidney of db/db mice. In a word, our findings suggest that DL-NBP may be a potential therapeutic drug in the treatment of DN.

10.
Oxid Med Cell Longev ; 2020: 8586314, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33354279

RESUMO

There is a high incidence of acute and chronic skin defects caused by various reasons in clinically practice. The repair and functional reconstruction of skin defects have become a major clinical problem, which needs to be solved urgently. Previous studies have shown that fibroblast growth factor 10 (FGF10) plays a functional role in promoting the proliferation, migration, and differentiation of epithelial cells. However, little is known about the effect of FGF10 on the recovery process after skin damage. In this study, we found that the expression of endogenous FGF10 was increased during wound healing. We prepared FGF10-loaded poly(lactic-co-glycolic acid) (FGF10-PLGA) microspheres, and it could sustain release of FGF10 both in vitro and in vivo, accelerating wound healing. Further analysis revealed that compared with FGF10 alone, FGF10-PLGA microspheres significantly improved granulation formation, collagen synthesis, cell proliferation, and blood vessel density. In the meantime, we found that FGF10-PLGA microspheres inhibited the expression of endoplasmic reticulum (ER) stress markers. Notably, activating ER stress with tunicamycin (TM) reduced therapeutic effects of FGF10-PLGA microspheres in wound healing, whereas inhibition of ER stress with 4-phenyl butyric acid (4-PBA) improved the function of FGF10-PLGA microspheres. Taken together, this study indicates that FGF10-PLGA microspheres accelerate wound healing presumably through modulating ER stress.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator 10 de Crescimento de Fibroblastos/farmacologia , Microesferas , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/farmacologia , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões , Administração Tópica , Animais , Masculino , Camundongos , Camundongos Endogâmicos ICR , Ferimentos e Lesões/tratamento farmacológico , Ferimentos e Lesões/metabolismo , Ferimentos e Lesões/patologia
11.
Food Sci Nutr ; 8(7): 3504-3514, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32724613

RESUMO

Lignin was isolated from wheat straw via organosolv process and further transferred to monophenolic compounds via oxidative conversion. Wheat straw lignin (WSL) with purity at 91.4 wt% was acquired in the presence of heterogeneous and recyclable catalyst of Amberlyst-45. WSL was characterized by infrared spectrometer (IR), nuclear magnetic resonance spectroscopy (NMR) including 1H NMR and 13C NMR spectra. The results showed that WSL possesses typical syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H) units, and it is mainly composed of S and G units. The product distribution was dependent on the composition of WSL. Derivatives from S and G units were found to be the main products. The oxidative conversion of WSL was performed by varying oxidant and catalyst. Both the formation of monophenolic compounds and aromatic aldehydes were enhanced by combining oxidants and catalysts. The composite catalyst composed of NaOH/NaAlO2 was effective for the oxidation of WSL in the presence of nitrobenzene and atmospheric pressure air. The total yield of monophenolic compounds reached up 18.1%, and yields at 6.3 and 5.7% for syringaldehyde and vanillin were achieved, respectively.

12.
Environ Sci Pollut Res Int ; 27(33): 42001-42021, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32700279

RESUMO

Human activities during each phase of coal mine life cycle greatly affect groundwater environment. The groundwater environment destruction is not just only the destruction of underground structure but also the social problems caused by available groundwater resources reduction, as well as the environmental problems affecting ecosystem and human health. Moreover, the groundwater environmental risk of coal mining is complex, dynamic, and long-term. Therefore, a framework and quantitative method for groundwater environmental risk analysis at different phases of the mine life cycle was presented, which is composed of the groundwater system destruction risk (GSDR) and social-economic-ecological vulnerability (SEEV) assessment. The framework was applied in Hongshan abandoned coal mine, North China. Based on the aquifer structure destruction, groundwater flow field evolution, contamination, and social-economic influence analysis, 12 main controlling factors for the GSDR and 7 factors for the SEEV were determined and quantified separately. The results showed that the groundwater contamination of the Hongshan mine mainly occurred after closure, caused by the cross-strata pollution of mine water, which significantly reduced the groundwater available resources, which greatly affected local social-economy sustainable development and residents' health. The Hongshan mine closure increased groundwater environmental risk, with the GSDR high-risk zone being 12.51 km2 larger than that during the mining phase and the SEEV was calculated at a high level. This framework promotes systematic integration of the groundwater environmental risk assessment in mine life cycle.


Assuntos
Minas de Carvão , Água Subterrânea , Animais , China , Carvão Mineral/análise , Ecossistema , Monitoramento Ambiental , Humanos , Medição de Risco
13.
Sci Rep ; 9(1): 19853, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882832

RESUMO

Landslide displacement time series can directly reflects landslide deformation and stability characteristics. Hence, forecasting of the non-linear and non-stationary displacement time series is necessary and significant for early warning of landslide failure. Traditionally, conventional machine learning methods are adopted as forecasting models, these forecasting models mainly determine the input and output variables experientially and does not address the non-stationary characteristics of displacement time series. However, it is difficult for these conventional machine learning methods to obtain appropriate input-output variables, to determine appropriate model parameters and to acquire satisfied prediction performance. To deal with these drawbacks, this study proposes the wavelet analysis (WA) to decompose the displacement time series into low- and high-frequency components to address the non-stationary characteristics; then proposes thee chaos theory to obtain appropriate input-output variables of forecasting models, and finally proposes Volterra filter model to construct the forecasting model. The GPS monitoring cumulative displacement time series, recorded on the Shuping and Baijiabao landslides, distance measuring equipment monitoring displacements on the Xintan landslide in Three Gorges Reservoir area of China, are used as test data of the proposed chaotic WA-Volterra model. The chaotic WA-support vector machine (SVM) model and single chaotic Volterra model without WA method, are used as comparisons. The results show that there are chaos characteristics in the GPS monitoring displacement time series, the non-stationary characteristics of landslide displacements are captured well by the WA method, and the model input-output variables are selected suitably using chaos theory. Furthermore, the chaotic WA-Volterra model has higher prediction accuracy than the chaotic WA-SVM and single chaotic Volterra models.

14.
J Nanosci Nanotechnol ; 16(2): 2032-41, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27433724

RESUMO

The CdS/C3N4 composites with efficient photocatalytic performance under visible light irradiation were synthesized by a facile sonochemical route. The as-prepared CdS/C3N4 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution trans- mission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance absorption spectra (DRS), fourier transform infrared spectroscopy (FTIR) and photoluminescence spectra (PL). The photocatalytic degradation of rhodamine B (RhB) by the CdS/C3N4 composites was explored and optimized, suggesting the optimal amount of CdS in the composites was 50 wt%. The significantly enhanced photocatalytic activity of CdS/C3N4 composites could be attributed to the effectively interfacial transfer of photogenerated charge carriers between CdS and C3N4, which restrained the recombination of electron-hole pairs.

15.
J Huazhong Univ Sci Technolog Med Sci ; 34(4): 582-585, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25135731

RESUMO

The clinical characteristics of painless aortic dissection were investigated in order to improve the awareness of diagnosis and treatment of atypical aortic dissection. The 482 cases of aortic dissection were divided into painless group and pain group, and the data of the two groups were retrospectively analyzed. The major clinical symptom was pain in 447 cases (92.74%), while 35 patients (7.26%) had no typical pain. The gender, age, hypertension, hyperlipidemia, diabetes, smoking and drinking history had no statistically significant differences between the two groups (P>0.05). The proportion of Stanford type A in painless group was significantly higher than that in pain group (48.57% vs. 21.03%, P=0.006). The incidence of unconsciousness in the painless group was significantly higher than that in the pain group (14.29% vs. 3.58%, P=0.011). The incidence of hypotension in painless group was significantly higher than that in pain group for 4.26 folds (P=0.01). Computed tomography angiography (CTA) examination revealed that the incidence of aortic arch involved in the painless group was significantly higher than that in the pain group (19.23% vs. 5.52%, P=0.019). It was concluded that the incidence of painless aortic dissection was higher in Stanford A type patients, commonly seen in the patients complicated with hypotension and unconsciousness. CTA examination revealed higher incidence of aortic arch involvement.


Assuntos
Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/fisiopatologia , Hipotensão/diagnóstico por imagem , Hipotensão/fisiopatologia , Inconsciência/diagnóstico por imagem , Inconsciência/fisiopatologia , Adulto , Idoso , Angiografia , Ruptura Aórtica/epidemiologia , Feminino , Humanos , Hipotensão/epidemiologia , Incidência , Masculino , Pessoa de Meia-Idade , Dor/diagnóstico por imagem , Dor/epidemiologia , Dor/fisiopatologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Inconsciência/epidemiologia
16.
Dalton Trans ; 43(3): 982-9, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24162386

RESUMO

Fullerene modified C3N4 (C60/C3N4) composites with efficient photocatalytic activity under visible light irradiation were fabricated by a simple adsorption approach. The as-prepared C60/C3N4 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance absorption spectra (DRS), Fourier transform infrared spectroscopy (FTIR) and photoluminescence spectra (PL). The photocatalytic degradation of rhodamine B (RhB) by the C60/C3N4 composites was investigated and optimized, suggesting that the optimal amount of C60 in the composites was 1 wt%. The significantly enhanced photocatalytic activity could be attributed to the efficient separation of photogenerated electrons and holes in the C60/C3N4 composites. A possible mechanism of C60/C3N4 composites as photocatalysts was proposed.

17.
Dalton Trans ; 42(10): 3402-9, 2013 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-23258545

RESUMO

A novel nanostructured carbon/TiO(2) nanocomposite photocatalyst is firstly fabricated via a facile hydrothermal process by using fullerene (C(60)) decorated single-walled carbon nanotubes (SWCNTs) as carbon source, which is denoted as C(60)-d-CNTs. The obtained nanostructured carbon/TiO(2) nanocomposites are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectra (DRS), Raman spectra, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectra (PL), and then are used as catalysts for photocatalytic hydrogen production. It is found that the kinds and contents of various carbon nanostructured materials (such as SWCNTs, C(60) and C(60)-d-CNTs) coupled with TiO(2) can significantly enhance the photoactivity for hydrogen production, and the 5 wt% C(60)-d-CNTs/TiO(2) nanocomposite exhibits the best performance. Experimental results suggest that the C(60)-d-CNTs as a novel carbon nanostructured material could be more beneficial for the photogenerated carrier separation than SWCNTs and C(60) when these carbon nanostructured materials are coupled with TiO(2).

18.
Phys Chem Chem Phys ; 14(48): 16745-52, 2012 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-23138223

RESUMO

Porous graphitic carbon nitride (g-C(3)N(4)) was prepared by a simple pyrolysis of urea, and then a g-C(3)N(4)-Pt-TiO(2) nanocomposite was fabricated via a facile chemical adsorption followed by a calcination process. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance absorption spectra, and electron microscopy. It is found that the visible-light-induced photocatalytic hydrogen evolution rate can be remarkably enhanced by coupling TiO(2) with the above g-C(3)N(4), and the g-C(3)N(4)-Pt-TiO(2) composite with a mass ratio of 70 : 30 has the maximum photoactivity and excellent photostability for hydrogen production under visible-light irradiation, and the stable photocurrent of g-C(3)N(4)-TiO(2) is about 1.5 times higher than that of the bare g-C(3)N(4). The above experimental results show that the photogenerated electrons of g-C(3)N(4) can directionally migrate to Pt-TiO(2) due to the close interfacial connections and the synergistic effect existing between Pt-TiO(2) and g-C(3)N(4) where photogenerated electrons and holes are efficiently separated in space, which is beneficial for retarding the charge recombination and improving the photoactivity.

19.
Nanoscale ; 4(7): 2372-7, 2012 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-22395742

RESUMO

Walnut-like In(2)S(3) microspheres were synthesized through an ionic liquid-assisted solvothermal method for the first time. The crystal structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and nitrogen adsorption-desorption measurement. It was found that the additional amount of ionic liquid, solvothermal temperature and time played crucial roles in controlling the structure and morphology of the In(2)S(3) microspheres. A possible formation mechanism of the walnut-like In(2)S(3) microsphere was proposed on the basis of the experimental results.


Assuntos
Índio/análise , Índio/química , Líquidos Iônicos/farmacologia , Microesferas , Microtecnologia/métodos , Selênio/análise , Selênio/química , Catálise , Juglans , Microscopia Eletrônica de Varredura , Modelos Biológicos , Nanoconchas/análise , Nanoconchas/química , Nanoconchas/ultraestrutura , Difração de Pó , Solventes/química , Solventes/farmacologia , Temperatura , Difração de Raios X
20.
Dalton Trans ; 41(4): 1179-86, 2012 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-22117224

RESUMO

Multiwalled carbon nanotubes (MWCNTs) and ZnIn(2)S(4) composites were prepared by a facile hydrothermal method, which was used for hydrogen production under visible-light (λ≥ 420 nm) irradiation. The obtained MWCNTs/ZnIn(2)S(4) composites were characterized by X-ray diffraction (XRD), thermogravimetric and differential scanning calorimetry analyses (TG-DSC), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance absorption spectra (DRS), Fourier transform IR spectroscopy (FTIR) and Photoluminescence spectra (PL). It was found that the MWCNTs were embedded into the interior of floriated ZnIn(2)S(4) microspheres. The effects of the composite ratio in the MWCNTs/ZnIn(2)S(4) on the photocatalytic activity for hydrogen production were investigated. The results show that the 3 wt% MWCNTs/ZnIn(2)S(4) composite reaches its maximum photocatalytic hydrogen production efficiency with an apparent quantum efficiency as high as 23.3% under 420 nm light irradiation. The significantly enhanced photoactivity for the present composite originates from the synergetic effect of its component intrinsic properties. A possible mechanism of the MWCNTs/ZnIn(2)S(4) composite as a photocatalyst for H(2) evolution was proposed.

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