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1.
Front Pharmacol ; 15: 1138251, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38708079

RESUMO

Background and aims: To investigate mechanisms underlying the effects of Da-Cheng-Qi decoction (DCQD) on severe acute pancreatitis (SAP) capillary leakage syndrome. Methods: In this study, a SAP rat model was established using retrograde perfusion of 5% sodium taurocholate into the biliopancreatic duct. The study included three randomized groups: control, SAP (modeling), and DCQD (via gavage at 2 h pre-modeling and 2 and 4 h post-modeling). HPLC was used to analyzed major components of DCQD. Pathological changes and capillary permeability in the rat pancreatic tissues were examined. mRNA levels of claudin 5, occludin, zonula occludin-1 (ZO-1), and junctional adhesion molecules (JAM-C) were assessed using qRT-PCR. Tight junction-associated protein expression was evaluated using immunofluorescence and Western blot analyses. Human umbilical vein endothelial cells (HUVECs) were used to investigate the mechanism m of DCQD. Results: Serum levels of amylase, TNF-α, IL-1ß, IL-2, and IL-6 were higher in the SAP group compared to the DCQD group (p < 0.05). DCQD treatment significantly attenuated rat pancreas damage (p < 0.05) and reduced tissue capillary permeability compared to the SAP group (p < 0.05). Claudin 5, occludin, and ZO-1 expression in the rat tissues was upregulated, but JAM-C was downregulated by DCQD treatment (p < 0.05). HUVEC permeability was improved by DCQD in a dose-time-dependent manner compared to the SAP group (p < 0.05). DCQD also upregulated claudin 5, occludin, and ZO-1 expression in vitro (p < 0.05). Conclusion: DCQD can improve capillary permeability in both in vivo and in vitro models of SAP by upregulating expression of claudin 5, occludin, and ZO-1, but not JAM-C.

2.
Chin J Integr Med ; 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37943488

RESUMO

OBJECTIVE: To investigate the effect of honokiol (HON) and the role of high-mobility group protein B1 (HMGB1) on the pathogenesis of severe acute pancreatitis (SAP). METHODS: Thirty mice were numbered according to weight, and randomly divided into 5 groups using a random number table, including control, SAP, SAP and normal saline (SAP+NS), SAP and ethyl pyruvate (SAP+EP), or SAP+HON groups, 6 mice in each group. Samples of pancreas, intestine, and blood were collected 12 h after SAP model induction for examination of pathologic changes, immune function alterations by enzyme linked immunosorbent assay (ELISA), and Western blot. In vitro experiments, macrophages were divided into 5 groups, the control, lipopolysaccharide (LPS), LPS+DMSO (DMSO), LPS+anti-HMGB1 monoclonal antibody (mAb), and LPS+ HON groups. The tight connection level was determined by transmission electron microscopy and fluorescein isothiocyanate-labeled. The location and acetylation of HMGB1 were measured by Western blot. Finally, pyridone 6 and silencing signal transducer and activator of the transcription 1 (siSTAT1) combined with honokiol were added to determine whether the Janus kinase (JAK)/ STAT1 participated in the regulation of honokiol on HMGB1. The protein expression levels of HMGB1, JAK, and STAT1 were detected using Western blot. RESULTS: Mice with SAP had inflammatory injury in the pancreas, bleeding of intestinal tissues, and cells with disrupted histology. Mice in the SAP+HON group had significantly fewer pathological changes. Mice with SAP also had significant increases in the serum levels of amylase, lipase, HMGB1, tumor necrosis factor- α, interleukin-6, diamine oxidase, endotoxin-1, and procalcitonin. Mice in the SAP+HON group did not show these abnormalities (P<0.01). Studies of Caco-2 cells indicated that LPS increased the levels of occludin and claudin-1 as well as tight junction permeability, decreased the levels of junctional adhesion molecule C, and elevated intercellular permeability (P<0.01). HON treatment blocked these effects. Studies of macrophages indicated that LPS led to low nuclear levels of HMGB1, however, HON treatment increased the nuclear level of HMGB1 (P<0.01). HON treatment also inhibited the expressions of JAK1, JAK2, and STAT1 (P<0.01) and increased the acetylation of HMGB1 (P<0.05). CONCLUSION: HON prevented intestinal barrier dysfunction in SAP by inhibiting HMGB1 acetylation and JAK/STAT1 pathway.

3.
Opt Lett ; 48(21): 5747-5750, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910749

RESUMO

While higher-order photonic topological corner states typically are created in systems with nontrivial bulk dipole polarization, they could also be created in systems with vanishing dipole polarization but with nontrivial quadrupole topology, which though is less explored. In this work, we show that simple all-dielectric photonic crystals in the Lieb lattice can host a topologically nontrivial quadrupole bandgap. Through a combination of symmetry analysis of the eigenmodes and explicit calculations of the Wannier bands and their polarization using the Wilson loop method, we demonstrate that the Lieb photonic crystals can have a bandgap with vanishing dipole polarization but with nontrivial quadrupole topology. The nontrivial bulk quadrupole moment could result in edge-localized polarization and topological corner states in systems with open edges. Interestingly, the indices of the corner states show an unusual "3+1" pattern compared to previously known "2+2" pattern, and this new pattern leads to unusual filling anomaly when the corner states are filled. Our work could not only deepen our understanding about quadrupole topology in simple all-dielectric photonic crystals but could also offer new opportunities for practical applications in integrated photonic devices.

4.
Nanomicro Lett ; 15(1): 212, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37707720

RESUMO

Hydrazine oxidation reaction (HzOR) assisted hydrogen evolution reaction (HER) offers a feasible path for low power consumption to hydrogen production. Unfortunately however, the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts, which are still challenging due to the totally different catalytic mechanisms. Herein, the [W-O] group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst, which possesses excellent catalytic performances towards both HER (185.60 mV at 1000 mA cm-2) and HzOR (78.99 mV at 10,00 mA cm-2) with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm-2. The introduction of [W-O] groups, working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation, leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in [W-O] group as well, resultantly boosting the hydrogen production and HzOR. Moreover, a proof-of-concept direct hydrazine fuel cell-powered H2 production system has been assembled, realizing H2 evolution at a rate of 3.53 mmol cm-2 h-1 at room temperature without external electricity supply.

5.
Adv Mater ; 35(32): e2304508, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37344386

RESUMO

Environmentally friendly electrochemical reduction of contaminated nitrate to ammonia (NO3 - RR) is a promising solution for large quantity ammonia (NH3 ) production, which, however, is a complex multi-reaction process involving coordination between different reaction intermediates of nitrate reduction and water decomposition-provided active hydrogen (Hads ) species. Here, a dual-site catalyst of [W-O] group-doped CoP nanosheets (0.6W-O-CoP@NF) has been designed to synergistically catalyze the NO3 - RR and water decomposition, especially the reactions between the intermediates of NO3 - RR and water decomposition-provided Hads species. This catalytic NO3 - RR exhibits an extremely high NH3 yield of 80.92 mg h-1 cm-2 and a Faradaic efficiency (FE) of 95.2% in 1 m KOH containing 0.1 m NO3 - . Significantly, 0.6W-O-CoP@NF presents greatly enhanced NH3 yield and FE in a wide NO3 - concentration ranges of 0.001-0.1 m compared to the reported. The excellent NO3 - RR performance is attributed to a synergistic catalytic effect between [W-O] and CoP active sites, in which the doped [W-O] group promotes the water decomposition to supply abundant Hads , and meanwhile modulates the electronic structure of Co for strengthened adsorption of Hads and the hydrogen (H2 ) release prevention, resultantly facilitating the NO3 - RR. Finally, a Zn-NO3 - battery has been assembled to simultaneously achieve three functions: electricity output, ammonia production, and nitrate treatment in wastewater.

6.
Nat Commun ; 14(1): 1997, 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37032360

RESUMO

Substituting hydrazine oxidation reaction for oxygen evolution reaction can result in greatly reduced energy consumption for hydrogen production, however, the mechanism and the electrochemical utilization rate of hydrazine oxidation reaction remain ambiguous. Herein, a bimetallic and hetero-structured phosphide catalyst has been fabricated to catalyze both hydrazine oxidation and hydrogen evolution reactions, and a new reaction path of nitrogen-nitrogen single bond breakage has been proposed and confirmed in hydrazine oxidation reaction. The high electro-catalytic performance is attributed to the instantaneous recovery of metal phosphide active site by hydrazine and the lowered energy barrier, which enable the constructed electrolyzer using bimetallic phosphide catalyst at both sides to reach 500 mA cm-2 for hydrogen production at 0.498 V, and offer an enhanced hydrazine electrochemical utilization rate of 93%. Such an electrolyzer can be powered by a bimetallic phosphide anode-equipped direct hydrazine fuel cell, achieving self-powered hydrogen production at a rate of 19.6 mol h-1 m-2.

7.
Nanoscale Adv ; 5(4): 1086-1094, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36798491

RESUMO

Semiconductor colloidal quantum dots (QDs) have been regarded as promising fluorescent materials for chemical sensing, bio-detection and optical communications; yet it still remains challenging to bring out self-powered photodetectors based solely on QDs because the excited charges within QDs are extremely immobile due to their reduced dimensionalities and they hardly form effective photocurrents. Hence, we have attempted to decouple the light-absorption and charge-transport criteria in order to feature highly-sensitive, rapid-response and self-driven photodetectors based on single-layer carbon QD layers (CQDLs) via facile in situ self-assembling deposition with fine control over thickness. We show explicit dark-current suppression by visualizing charge blocking phenomena and screen effects due to layered CQDL structures, which alleviate the movement of leakage carriers crossing over the CQD interlayers. By examining the distribution of electric fields within CQDLs under light excitation, the spatial dependence of the light-trapping effect within CQDLs was confirmed. These features are strongly associated with the thickness tuning of CQDLs, while 65 nm of CQDL thickness could manifest remarkable photoresponsivity above 9.4 mA W-1 and detectivity above 5.9 × 1012 under broadband light illumination. These results demonstrate the insights gained from an understanding of broadband optoelectronics, which might potentially pave the way for further employment in functional photodetection.

8.
Medicine (Baltimore) ; 101(44): e31238, 2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36343047

RESUMO

At present, the mechanism of reciprocal ST-segment depression (RSTD) is unclear. ST-segment changes may be caused by the potential difference between the positive and negative electrodes, although this requires further investigation. The characteristics of RSTD and their relationship with ST-segment elevation in acute ST segment elevation myocardial infarction (STEMI) patients were analyzed. We replaced the negative electrode of the precordial leads of an inferior wall myocardial infarction patient and observed the changes in the ST-segment of the precordial leads. A total of 85 patients were included, of which 75 were patients with RSTD. All 45 patients with inferior myocardial infarction had limb lead RSTD, and 37 had anterior lead ST-segment depression. All ST-segment changes in STEMI can be explained by the proposed mechanism, and the value of ST segment depression in limb leads can be calculated by the value of ST segment elevation. In summary, the mechanism of RSTD in acute myocardial infarction may be that the action potential (AP) of the negative electrode of the lead weakens or disappears and the AP of the positive electrode may not be completely offset, resulting in ST-segment depression. Animal experimental studies are needed for further confirmation. When the negative electrode of the precordial lead is changed in acute inferior wall myocardial infarction patient, the ST-segment of the precordial lead changes accordingly. All the changes are consistent with our analysis.


Assuntos
Infarto Miocárdico de Parede Anterior , Infarto Miocárdico de Parede Inferior , Infarto do Miocárdio , Infarto do Miocárdio com Supradesnível do Segmento ST , Humanos , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico , Depressão , Eletrocardiografia , Infarto do Miocárdio/diagnóstico , Arritmias Cardíacas
9.
Appl Opt ; 61(23): 6905-6914, 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-36255772

RESUMO

Single-pixel imaging (SPI) is a new technology with many applications and prospects. Polarization detection technology can improve the detection and identification ability of the imaging system. A near-infrared polarization SPI lidar system is designed to realize detection and polarization imaging of outdoor long-range targets. The depth, intensity, linear polarization, and polarization degree images of typical remote targets are obtained. The results show that the polarization image contains many details and contour information of the target, and the intensity image contains brightness and reflectivity information. Intensity and polarization information complement each other. The characteristics of intensity and polarization images at different spatial frequencies are analyzed for the first time, to our knowledge, by taking advantage of the Fourier modulation mode. We found that the proportion of high-frequency information in the polarization image is much higher than that of the intensity image. The sampling strategy of collecting only low-frequency components is applicable in intensity imaging but needs further improvement in polarization imaging. The polarization SPI lidar system can enrich the target information acquired, improve imaging contrast, and have significant application value for target detection and identification in complex backgrounds.

10.
Small ; 18(48): e2204443, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36257819

RESUMO

Earth-abundant tungsten carbide exhibits potential hydrogen evolution reaction (HER) catalytic activity owing to its Pt-like d-band electronic structure, which, unfortunately, suffers from the relatively strong tungsten-hydrogen binding, deteriorating its HER performance. Herein, a catalyst design concept of incorporating late transition metal into early transition metal carbide is proposed for regulating the metal-H bonding strength and largely enhancing the HER performance, which is employed to synthesize CoW bi-metallic carbide Co6 W6 C by a "disassembly-assembly" approach in a confined environment. Such synthesized Co6 W6 C nanocatalyst features the optimal Gibbs free energy of *H intermediate and dissociation barrier energy of H2 O molecules as well by taking advantage of the electron complementary effect between Co and W species, which endows the electrocatalyst with excellent HER performance in both alkaline and seawater/alkaline electrolytes featuring especially low overpotentials, elevated current densities, and much-enhanced operation durability in comparison to commercial Pt/C catalyst. Moreover, a proof-of-concept Mg/seawater battery equipped with Co6 W6 C-2-600 as cathode offers a peak power density of 9.1 mW cm-2 and an open-circuit voltage of ≈1.71 V, concurrently realizing hydrogen production and electricity output.

11.
Opt Express ; 30(21): 37484-37492, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36258336

RESUMO

Long-range light detection and ranging (lidar) of active illumination optical imaging has widespread applications, such as remote sensing, satellite-based global topography, and target recognition and identification. Here, to make trade-offs among imaging efficiency, resolution, receiving field of view, divergence angle, and detected distance, we demonstrate a scanning single-pixel imaging lidar (SSPIL), enjoying the merits of the traditional pointing-by-pointing scanning imaging and single-pixel imaging. The imaging strategy of SSPIL is divided into scanning search and staring imaging processes. These strategies can save most time consumption for imaging background areas and thus improve imaging efficiency. Three imaging experiments were conducted in real urban atmospheric conditions. The preliminary results show SSPIL has the ability for long-range imaging with high efficiency, high resolution, and a large receiving field of view. Also, from the imaging results, we found that multiple samples can improve the SNR of imaging in the real urban atmosphere. The present work may provide a valuable alternative approach in the long-range active illumination optical imaging fields.

12.
Medicine (Baltimore) ; 101(38): e30812, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36197171

RESUMO

There has been an epidemic of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) delta variant in Jingmen, China, and the clinical and epidemiological characteristics of all patients infected with SARS-CoV-2 delta variant in an epidemic are rarely reported. All the coronavirus disease 2019 (COVID-19) patients diagnosed in Jingmen in August 2021 were enrolled in this study. Epidemiological data and clinical characteristics were analyzed. Of 58 patients (38 male and 20 female), 11 were children. The mean age was 35 years, and the median age was 39 years (range, 1-60 years; interquartile range, 28-51). The infectivity of the SARS-CoV-2 Delta variant may have increased, but pathogenicity could have decreased significantly. The vast majority of patients had either no symptoms or mild symptoms. Even though the variant virus is highly contagious, control measures have proven effective. Symptoms included fever (53%), cough (48%), headache (6%), runny nose (13%), loss of smell and taste (6%), elevated C-reactive protein (26%), increased neutrophil count (13%), decreased eosinophil count (21%), and elevated mononuclear granulocytes (26%). Thirty-eight of the 47 adults showed lymphocyte decline, but none of the children showed a significant decline, and more than half of them showed an increase. Thirty patients had no pneumonia, 27 patients had mild pneumonia, and only one patient with multiple chronic diseases had severe pneumonia. None of the 11 children had been vaccinated, 10 did not have pneumonia, and 1 had a small lung lesion. The number of new patients disappeared in 15 days after the lockdown of the city.


Assuntos
COVID-19 , SARS-CoV-2 , Adolescente , Adulto , Proteína C-Reativa/metabolismo , COVID-19/epidemiologia , Criança , Pré-Escolar , China/epidemiologia , Controle de Doenças Transmissíveis , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
13.
Nanomaterials (Basel) ; 12(15)2022 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-35957070

RESUMO

The development of bifunctional electrocatalysts with efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is still a key challenge at the current stage. Herein, FeNi LDH/V2CTx/nickel foam (NF) self-supported bifunctional electrode was prepared via deposition of FeNi LDH on V2CTx/NF substrate by hydrothermal method. Strong interfacial interaction between V2CTx/NF and FeNi LDH effectively prevented the aggregation of FeNi LDH, thus exposing more catalytic active sites, which improved electrical conductivity of the nanohybrids and structural stability. The results indicated that the prepared FeNi LDH/V2CTx/NF required 222 mV and 151 mV overpotential for OER and HER in 1 M KOH to provide 10 mA cm-2, respectively. Besides, the FeNi LDH/V2CTx/NF electrocatalysts were applied to overall water splitting, which achieved a current density of 10 mA cm-2 at 1.74 V. This work provides ideas for improving the electrocatalytic performance of electrocatalysts through simple synthesis strategies, structural adjustment, use of conductive substrates and formation of hierarchical structures.

14.
Opt Lett ; 47(12): 3123-3126, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35709066

RESUMO

Single-pixel imaging (SPI), a novel computational imaging technique that has emerged in the past decades, can effectively capture the image of a static object by consecutively measuring light intensities from it. However, when SPI is applied to imaging the dynamic object, severe motion blur in the restored image tends to appear. In this Letter, a new SPI scheme is proposed to largely alleviate such a problem by leveraging a calibrated radon spectrum. Such a spectrum is obtained by translating the acquired one-dimensional projection functions (1DPFs) according to the positional relationship among the 1DPFs. Simulation and experimental results demonstrate that, without prior knowledge, our approach can effectively reduce motion blur and restore high-quality images of the fast-moving object. In addition, the proposed scheme can also be used for fast object tracking.


Assuntos
Radônio , Simulação por Computador , Diagnóstico por Imagem , Movimento (Física)
15.
Angew Chem Int Ed Engl ; 61(32): e202207226, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35638129

RESUMO

A novel Zn-Fe flow battery featuring an Fe3+ reduction reaction (Fe3+ RR)-coupled zinc oxidation, and an Fe2+ oxidation reaction (Fe2+ OR)-coupled hydrogen evolution reaction (HER) system as well, was established. This battery is capable of driving two Fe2+ OR-coupled HER systems in series based on the above Fe2+ /Fe3+ cycling, for efficient self-powered hydrogen evolution. Meanwhile, this Fe2+ /Fe3+ cycling enables the preparation of a multifunctional catalyst, Pt-3@SXNS (siloxene nanosheet), by the Fe2+ OR-promoted dispersion of Pt nanoparticles on SXNS; alternatively, this support could be obtained by Fe3+ RR-assisted exfoliation using Fe3+ from the anolyte of Fe2+ OR-coupled HER. The Pt-3@SXNS catalyst exhibits excellent catalytic activities toward Fe3+ RR in the Zn-Fe flow battery, HER, and Fe2+ OR in the electrolyzer, which is attributed to the strong electronic interaction between Pt and Si. This work offers a new strategy for energy storage and low-cost hydrogen production from acidic wastewater.

16.
J Back Musculoskelet Rehabil ; 35(6): 1311-1319, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35599469

RESUMO

BACKGROUND: Non-specific low back pain (NS-LBP) is a serious public health problem. Tai Chi is promising in reducing the risk of falls and alleviating symptoms in this population. OBJECTIVE: To investigate the effect of Tai Chi on gait and dynamic balance in elderly women with NS-LBP. METHODS: 20 women (age > 65 yr.) with NS-LBP were randomly assigned to a Tai Chi group (n= 10) or a control group (n= 10). The Tai Chi group practiced Tai Chi exercise 3 times a week for 6 weeks. Each session lasted 60 minutes. Pain, spatiotemporal gait features and dynamic balancing capacity were assessed at 0 and 6 weeks. RESULTS: Compared to the control group at 6 weeks, the Tai Chi group had a significant decrease in VAS (p= 0.027) and stride width (p= 0.019), significant improvement in gait velocity, stride length (p< 0.001). Regarding dynamic balance capacity, the Tai Chi group had significant improvements in anterior (Left: p= 0.001; Right: p= 0.038), postero-lateral (Left: p< 0.001; Right: p= 0.038), and postero-medial (Left: p= 0.015; Right: p= 0.018). CONCLUSION: 6-week Tai Chi can relieve pain and improve gait and dynamic balance in elderly women with NS-LBP, which suggests Tai Chi could be a promising rehabilitation intervention to reduce the risk of falls in this population.


Assuntos
Dor Lombar , Tai Chi Chuan , Humanos , Feminino , Idoso , Equilíbrio Postural , Dor Lombar/terapia , Marcha , Acidentes por Quedas/prevenção & controle , Dor nas Costas
17.
Opt Lett ; 47(4): 870-873, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35167546

RESUMO

Target tracking has found important applications in particle tracking, vehicle navigation, aircraft monitoring, etc. However, employing single-pixel imaging techniques to track a fast-moving object with a high frame rate is still a challenge, due to the limitation of the modulation frequency of the spatial light modulator and the number of required patterns. Here we report a complementary single-pixel object tracking approach which requires only two geometric moment patterns to modulate the reflected light from a moving object in one frame. Using the complementary nature of a digital micromirror device (DMD), two identical single-pixel detectors are used to measure four intensities which can be used to acquire the values of zero-order and first-order geometric moments to track the centroid of a fast-moving object. We experimentally demonstrate that the proposed method successfully tracks a fast-moving object with a frame rate of up to 11.1 kHz in the first two experiments. In the third experiment, we compare previous works and find that the method can also accurately track a fast-moving object with a changing size and moving speed of 41.8 kilopixel/s on the image plane. The root mean squared errors in the transverse and axial directions are 0.3636 and 0.3640 pixels, respectively. The proposed method could be suitable for ultrafast target tracking.

18.
Angew Chem Int Ed Engl ; 61(15): e202116290, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35075773

RESUMO

Fe-N-C electrocatalysts have been demonstrated to be the most promising substitutes for benchmark Pt/C catalysts for the oxygen reduction reaction (ORR). Herein, we report that N-doped carbon materials with trace amounts of iron (0-0.08 wt. %) show excellent ORR activity and durability comparable and even superior to those of Pt/C in both alkaline and acidic media without significant contribution by the metal sites. Such an N-doped carbon (denoted as N-HPCs) features a hollow and hierarchically porous architecture, and more importantly, a noncovalently bonded N-deficient/N-rich heterostructure providing the active sites for oxygen adsorption and activation owing to the efficient electron transfer between the layers. The primary Zn-air battery using N-HPCs as the cathode delivers a much higher power density of 158 mW cm-2 , and the maximum power density in the H2 -O2 fuel cell reaches 486 mW cm-2 , which is comparable to and even better than those using conventional Fe-N-C catalysts at cathodes.

19.
Nanomaterials (Basel) ; 13(1)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36615984

RESUMO

Developing highly efficient, cost effective and durable bifunctional electrocatalyst remains a key challenge for overall water splitting. Herein, a bifunctional catalyst CoP2-Mo4P3/NF with rich heterointerfaces was successfully prepared by a two-step hydrothermal-phosphorylation method. The synergistic interaction between CoP2 and Mo4P3 heterogeneous interfaces can optimize the electronic structure of active sites, leading to the weak adsorption of H on the Mo sites and the increased redox activity of the Co site, resultantly improving the HER/OER bifunctional catalytic activity. The synthesized CoP2-Mo4P3/NF catalyst exhibits excellent electrocatalytic activity in 1.0 M KOH with low overpotentials of 77.6 and 300.3 at 100 mA cm-2 for HER and OER, respectively. Additionally, the assembled CoP2-Mo4P3/NF||CoP2-Mo4P3/NF electrolyzer delivers a current density of 100 mA cm-2 at a cell voltage of 1.59 V and remains stable for at least 370 h at 110 mA cm-2, indicating the potential application prospective in water splitting.

20.
Opt Express ; 29(19): 30327-30336, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34614758

RESUMO

Real-time tracking of fast-moving object have many important applications in various fields. However, it is a great challenge to track of fast-moving object with high frame rate in real-time by employing single-pixel imaging technique. In this paper, we present the first single-pixel imaging technique that measures zero-order and first-order geometric moments, which are leveraged to reconstruct and track the centroid of a fast-moving object in real time. This method requires only 3 geometric moment patterns to illuminate a moving object in one frame. And the corresponding intensities collected by a single-pixel detector are equivalent to the values of the zero-order and first-order geometric moments. We apply this new approach of measuring geometric moments to object tracking by detecting the centroid of the object in two experiments. The root mean squared errors in the transverse and axial directions are 5.46 pixels and 5.53 pixels respectively, according to the comparison of data captured by a camera system. In the second experiment, we successfully track a moving magnet with a frame rate up to 7400 Hz. The proposed scheme provides a new method for ultrafast target tracking applications.

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