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1.
Small ; : e2402927, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38794873

RESUMO

Na3V2(PO4)3 is a promising high-voltage cathode for aqueous zinc-ion batteries (ZIBs) and organic sodium-ion batteries (SIBs). However, the poor rate capability, specific capacity, and cycling stability severely hamper it from further development. In this work, Na3V2(PO4)3 (NVP) with vanadium nitride (VN) quantum dots encapsulated by nitrogen-doped carbon (NC) nanoflowers (NVP/VN@NC) are manufactured as cathode using in situ nitridation, carbon coating, and structural adjustment. The outer NC layer increases the higher electronic conductivity of NVP. Furthermore, VN quantum dots with high theoretical capacity not only improve the specific capacity of pristine NVP, but also serve as abundant "pins" between NVP and NC to strengthen the stability of NVP/VN@NC heterostructure. For Zn-ion storage, these essential characteristics allow NVP/VN@NC to attain a high reversible capacity of 135.4 mAh g-1 at 0.1 A g-1, and a capacity retention of 91% after 2000 cycles at 5 A g-1. Meanwhile, NVP/VN@NC also demonstrates to be a stable cathode material for SIBs, which can reach a high reversible capacity of 124.5 mAh g-1 at 0.1 A g-1, and maintain 92% of initial capacity after 11000 cycles at 5 A g-1. This work presents a feasible path to create innovative high-voltage cathodes with excellent reaction kinetics and structural stability.

2.
BMC Cancer ; 24(1): 800, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38965506

RESUMO

Drug resistance remains a significant challenge in the treatment of pancreatic cancer. The development of drug-resistant cell lines is crucial to understanding the underlying mechanisms of resistance and developing novel drugs to improve clinical outcomes. Here, a novel pancreatic cancer cell line, PDAC-X1, derived from Chinese patients has been established. PDAC-X1 was characterized by the immune phenotype, biology, genetics, molecular characteristics, and tumorigenicity. In vitro analysis revealed that PDAC-X1 cells exhibited epithelial morphology and cell markers (CK7 and CK19), expressed cancer-associated markers (E-cadherin, Vimentin, Ki-67, CEA, CA19-9), and produced pancreatic cancer-like organs in suspension culture. In vivo analysis showed that PDAC-X1 cells maintained tumorigenicity with a 100% tumor formation rate. This cell line exhibited a complex karyotype, dominated by subtriploid karyotypes. In addition, PDAC-X1 cells exhibited intrinsic multidrug resistance to multiple drugs, including gemcitabine, paclitaxel, 5-fluorouracil, and oxaliplatin. In conclusion, the PDAC-X1 cell line has been established and characterized, representing a useful and valuable preclinical model to study the underlying mechanisms of drug resistance and develop novel drug therapeutics to improve patient outcomes.


Assuntos
Carcinoma Ductal Pancreático , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Neoplasias Pancreáticas , Humanos , Linhagem Celular Tumoral , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Animais , Camundongos , Resistência a Múltiplos Medicamentos/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Masculino , Feminino , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Gencitabina , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico
3.
Int J Neurosci ; : 1-7, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38525692

RESUMO

OBJECTIVE: This research aimed to ascertain the effects of acupuncture at myofascial trigger points (MTrPs) in combination with sling exercise therapy (SET) on the clinical recovery and cervical spine biomechanics in patients with cervical spondylotic radiculopathy (CRS). METHODS: Eighty patients with CSR were divided into Group A and Group B. Group A was treated with acupuncture at MTrPs, and Group B was treated with acupuncture at MTrPs combined with SET. The cervical spine function, pain level, cervical spine biomechanics and the occurrence of complications were compared between the two groups before and after treatment. RESULTS: After treatment, the Japanese Orthopaedic Association scores, Clinical Assessment Scale for Cervical Spondylosis scores, cervical forward flexion angle, posterior extension angle, left lateral flexion angle, right lateral flexion angle, left lateral rotation angle, and right lateral rotation angle of the Group B were raised, and the Neck Disability index, Visual Analogue Scale scores, and Neck Pain Questionnaire scores were reduced versus those of the Group A. The difference in complication rates between the two groups was not of statistical significance. CONCLUSION: Acupuncture at MTrPs combined with SET promotes functional recovery of the cervical spine, reduces pain, and improves cervical spine biomechanics in patients with CRS.

4.
BMC Pulm Med ; 23(1): 436, 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37946130

RESUMO

OBJECTIVE: Fucosyltransferases (FUTs) molecules have been identified to be involved in carcinogenesis of malignant tumors. Nevertheless, the biological function of fucosyltransferases-3 (FUT3) in lung adenocarcinoma (LUAD) malignant phenotype remains unclear. Herein, we investigated the association between FUT3 and LUAD pathological process. METHODS: Immunochemistry, RT-qPCR and western blot assays were conducted to evaluate the expression of FUT3 in LUAD and corresponding adjacent tissues. The prognostic value of FUT3 was assessed via Kaplan­Meier plotter database. The biological process and potential mechanism of FUT3 in LUAD were conducted via GSEA. Additionally, immunofluorescence and metabolite activity detection were performed to determine the potential role of FUT3 in LUAD glucose metabolism. The active biomarkers associated with NF-κB signaling pathway were detected via western blot. Subcutaneous tumor model was conducted to analyze the effect of FUT3 on tumorigenesis of LUAD. RESULTS: FUT3 was remarkably upregulated in LUAD tissues compared with adjacent tissues from individuals. FUT3 overexpression may predict poor prognosis of LUAD patients. Knockdown of FUT3 significantly inhibited tumor proliferation, migration and glucometabolic alteration in LUAD cells. Moreover, GSEA demonstrated that elevated FUT3 was positively related to NF-κB signaling pathway. Additionally, in vitro and in vivo assays also indicated that downregulation of FUT3 resulted in the suppression of oncogenesis and glucose metabolism via inactivation of NF-κB pathway. CONCLUSION: Our findings demonstrated that FUT3 was involved in glucometabolic process and tumorigenesis of LUAD via NF-κB signaling pathway. FUT3 may be an optimal target for diagnosis and treatment of LUAD patients.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Adenocarcinoma de Pulmão/genética , Carcinogênese , Linhagem Celular Tumoral , Proliferação de Células , Transformação Celular Neoplásica , Fucosiltransferases/genética , Glucose , Neoplasias Pulmonares/genética , NF-kappa B
5.
BMC Endocr Disord ; 22(1): 107, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35443670

RESUMO

BACKGROUND: Thyroid cancer is the most prevalent endocrine malignancy. Long non-coding RNA (lncRNA) MIR31HG is abnormally expressed in thyroid cancer tissues. However, the precise, critical role of MIR31HG in thyroid cancer development remains unclear. METHODS: MIR31HG, microRNA (miR)-761 and mitogen-activated protein kinase 1 (MAPK1) were quantified by quantitative real-time PCR (qRT-PCR) and immunoblotting. Cell viability, proliferation, apoptosis, invasion and migration abilities were evaluated by MTS, 5-Ethynyl-2'-Deoxyuridine (EdU), flow cytometry, transwell and wound-healing assays, respectively. Dual-luciferase reporter assays were used to validate the direct relationship between miR-761 and MIR31HG or MAPK1. RESULTS: MIR31HG was overexpressed in human thyroid cancer, and its overexpression predicted poor prognosis. Suppression of MIR31HG impeded cell proliferation, invasion and migration, as well as promoted cell apoptosis in vitro, and diminished the growth of xenograft tumors in vivo. Mechanistically, MIR31HG targeted and regulated miR-761. Moreover, miR-761 was identified as a molecular mediator of MIR30HG function in regulating thyroid cancer cell behaviors. MAPK1 was established as a direct and functional target of miR-761 and MAPK1 knockdown phenocopied miR-761 overexpression in impacting thyroid cancer cell behaviors. Furthermore, MIR31HG modulated MAPK1 expression by competitively binding to miR-761 via the shared binding sequence. CONCLUSION: Our findings demonstrate that MIR31HG targets miR-761 to regulate the functional behaviors of thyroid cancer cells by upregulating MAPK1, highlighting a strong rationale for developing MIR31HG as a novel therapeutic target against thyroid cancer.


Assuntos
MicroRNAs , RNA Longo não Codificante/genética , Neoplasias da Glândula Tireoide , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/metabolismo
6.
Angew Chem Int Ed Engl ; 61(38): e202206544, 2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-35916327

RESUMO

Electrochemical production of hydrogen peroxide (H2 O2 ) from O2 on single-atom catalysts has attracted great attention, yet the quest for robust catalysts is driven by achieving >90 % Faradaic efficiency (FE) under industrial-relevant current densities (>100 mA cm-2 ). Herein we synthesize a catalyst that contains single nickel site coordinated by four nitrogen and two oxygen atoms (i.e., N4 Ni1 O2 ) via involving carboxyl functionalized multiwall carbon nanotubes as a substrate to provide extra O coordination to the regular NiN4 site. It has a cathodic energy efficiency of approximately 82 % and a H2 O2 FE of around 96 % at 200 mA cm-2 current density, outperforming the reported single-atom catalysts for H2 O2 electrosynthesis.

7.
Sensors (Basel) ; 21(21)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34770520

RESUMO

This paper proposes a parameter identification method for the multiparameter identification study of the linear-arch composite beam piezoelectric energy harvester. According to the voltage response characteristics of the system under short-circuit conditions, the mechanical equation is solved by transient excitation, combined with the backbone curve theory and logarithmic attenuation method, to obtain the system's linear damping, linear stiffness, and nonlinear stiffness. According to the voltage response characteristics of the system under open-circuit conditions, combined with the electrical equations, the system electromechanical coupling coefficient and equivalent capacitance coefficient are obtained; numerical simulation results show that the identification parameters have good accuracy. Finally, an experimental platform was built for verification, and the results show that the method has high accuracy and practicability.

8.
Nano Lett ; 14(3): 1172-7, 2014 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-24506191

RESUMO

Dealloyed nanoporous metals have attracted much attention because of their excellent catalytic activities toward various chemical reactions. Nevertheless, coarsening mechanisms in these catalysts have not been experimentally studied. Here, we report in situ atomic-scale observations of the structural evolution of nanoporous gold during catalytic CO oxidation. The catalysis-induced nanopore coarsening is associated with the rapid diffusion of gold atoms at chemically active surface steps and the surface segregation of residual Ag atoms, both of which are stimulated by the chemical reaction. Our observations provide the first direct evidence that planar defects hinder nanopore coarsening, suggesting a new strategy for developing structurally stable and highly active heterogeneous catalysts.

9.
Angew Chem Int Ed Engl ; 54(28): 8100-4, 2015 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-26014715

RESUMO

We report a novel multicomponent mixed-valence oxyhydroxide-based electrode synthesized by electrochemical polarization of a de-alloyed nanoporous NiCuMn alloy. The multicomponent oxyhydroxide has a high specific capacitance larger than 627 F cm(-3) (1097±95 F g(-1) ) at a current density of 0.25 A cm(-3) , originating from multiple redox reactions. More importantly, the oxyhydroxide electrode possesses an extraordinarily wide working-potential window of 1.8 V in an aqueous electrolyte, which far exceeds the theoretically stable window of water. The realization of both high specific capacitance and high working-potential windows gives rise to a high energy density, 51 mWh cm(-3) , of the multicomponent oxyhydroxide-based supercapacitor for high-energy and high-power applications.

10.
J Colloid Interface Sci ; 659: 868-877, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38219305

RESUMO

A recyclable hard-template method is proposed to exploit spindle-shaped hollow nitrogen-doped amorphous carbon (h-NAC) with a large number of short-range curved carbon fragments as anodes for lithium/sodium ion batteries (LIBs/SIBs). Besides providing adsorption sites due to the high existence of oxygen-containing functional groups (CO and COOH), the heavily exposed edge regions also provide a favorable storage environment with high adsorption energy for Li+/Na+ due to their short-range curved structure. Importantly, the etching solution of hard templates can be recycled to generate the FeOOH nanospindles as a precursor through a simple chemical titration, which supplies a new idea for the green preparation of hollow materials. The h-NAC electrode is proven to be bifunctional for storing lithium and sodium ions, displaying favorable rate capability (255 mAh g-1 and 106 mAh g-1 at 5 A g-1 for LIBs and SIBs, respectively). After 1000 cycles at 1 A g-1, the reproducible capacities of the LIBs and SIBs kept 496 mAh g-1 and 181 mAh g-1, respectively.

11.
J Colloid Interface Sci ; 667: 441-449, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38642483

RESUMO

In this study, a flexible, free-standing Fe-doped CoP nanoarrays electrode for superior lithium-ion storage has been successfully fabricated. The electrode combines the advantages of a Fe-doping and a flexible carbon cloth (CC) support, resulting in a high specific capacity (1356 mAh/g at 0.2 A/g) and excellent cycling stability (1138 mAh/g after 100 cycles). The cyclic voltammetry (CV) curves at different scan rates investigate the outstanding lithium storage behavior of Fe-CoP-NAs/CC which indicates a combined influence of diffusion behavior and capacitance behavior on the electrochemical process. The galvanostatic intermittent titration technique (GITT) analyzes the diffusion kinetics of Li+ which indicates the fast diffusion kinetics in the Fe-CoP/NAs/CC anode. The assembled Fe-CoP-NAs/CC//LiFePO4 battery exhibits a remarkable capacity of 325.2 mAh/g even at 5 A/g. And the battery also has good cycle stability, and still provides 498.1 mAh/g specific capacity after 200 cycles. Moreover, the Fe-CoP-NAs/CC//LiFePO4 soft-pack battery can continuously power the LEDs when it is bent at various angles which demonstrates its potential for use in wearable devices.

12.
J Clin Med ; 12(5)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36902523

RESUMO

The aim of this study was to explore the relationship between lipids with different structural features and lung cancer (LC) risk and identify prospective biomarkers of LC. Univariate and multivariate analysis methods were used to screen for differential lipids, and two machine learning methods were used to define combined lipid biomarkers. A lipid score (LS) based on lipid biomarkers was calculated, and a mediation analysis was performed. A total of 605 lipid species spanning 20 individual lipid classes were identified in the plasma lipidome. Higher carbon atoms with dihydroceramide (DCER), phosphatidylethanolamine (PE), and phosphoinositols (PI) presented a significant negative correlation with LC. Point estimates revealed the inverse associated with LC for the n-3 PUFA score. Ten lipids were identified as markers with an area under the curve (AUC) value of 0.947 (95%, CI: 0.879-0.989). In this study, we summarized the potential relationship between lipid molecules with different structural features and LC risk, identified a panel of LC biomarkers, and demonstrated that the n-3 PUFA of the acyl chain of lipids was a protective factor for LC.

13.
J Am Chem Soc ; 134(42): 17536-42, 2012 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-23020313

RESUMO

We report for the first time the highly selective semihydrogenation of alkynes using the unsupported nanoporous gold (AuNPore) as a catalyst and organosilanes with water as a hydrogen source. Under the optimized reaction conditions, the present semihydrogenation of various terminal- and internal-alkynes affords the corresponding alkenes in high chemical yields and excellent Z-selectivity without any over-reduced alkanes. The use of DMF as solvent, which generates amines in situ, or pyridine as an additive is crucial to suppress the association of hydrogen atoms on AuNPore to form H(2) gas, which is unable to reduce alkynes on the unsupported gold catalysts. The AuNPore catalyst can be readily recovered and reused without any loss of catalytic activity. In addition, the SEM and TEM characterization of nanoporosity show that the AuNPore catalyst has a bicontinuous 3D structure and a high density of atomic steps and kinks on ligament surfaces, which should be one of the important origins of catalytic activity.


Assuntos
Alcenos/síntese química , Alcinos/química , Aminas/química , Ouro/química , Nanopartículas Metálicas/química , Alcenos/química , Hidrogenação , Estrutura Molecular , Tamanho da Partícula , Porosidade , Propriedades de Superfície
14.
Micromachines (Basel) ; 13(5)2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35630281

RESUMO

Collecting vibration energy in the environment is expected to solve the problem of the self-power supply of wireless monitoring nodes in underground coal mines. By introducing nonlinear factors, a linear-arch bi-stable piezoelectric energy harvester (LBPEH) is designed. In order to reveal the influence of system parameters on the dynamic characteristics of LBPEH, the magnetic force model is established by the magnetizing current method, and the restoring force model is acquired through experimental measurement. The electromechanical coupling dynamics model of the system is established based on the Lagrange equation and Kirchhoff's law. The influence of excitation amplitude and excitation frequency on the dynamic characteristics of the piezoelectric energy harvester is simulated and analyzed. Moreover, experiments are designed to verify the results of the simulation. The results reveal that the restoring force of the linear-arch beam is nonlinear, and the LBPEH constructed by the linear-arch beam has an asymmetric potential well. Changing the excitation frequency or excitation amplitude can make the system in the well chaotic and achieve a large periodic motion state. With the increase of excitation amplitude, it is beneficial for the system to realize large periodic motion. The research provides theoretical guidance for the design of piezoelectric energy harvesters for different excitation conditions.

15.
Front Immunol ; 13: 906420, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36275646

RESUMO

Background: DERL3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, the correlation of DERL3 expression with the malignant phenotype of lung adenocarcinoma (LUAD) cells is unclear and remains to be elucidated. Herein, we investigated the interaction between the DERL3 and LUAD pathological process. Methods: The Cancer Genome Atlas (TCGA) database was utilized to determine the genetic alteration of DERL3 in stage I LUAD. Clinical LUAD samples including carcinoma and adjacent tissues were obtained and were further extracted to detect DERL3 mRNA expression via RT-qPCR. Immunohistochemistry was performed to evaluate the protein expression of DERL3 in LUAD tissues. The GEPIA and TIMER website were used to evaluate the correlation between DERL3 and immune cell infiltration. We further used the t-SNE map to visualize the distribution of DERL3 in various clusters at the single-cell level via TISCH database. The potential mechanisms of the biological process mediated by DERL3 in LUAD were conducted via KEGG and GSEA. Results: It was indicated that DERL3 was predominantly elevated in carcinoma compared with adjacent tissues in multiple kinds of tumors from the TCGA database, especially in LUAD. Immunohistochemistry validated that DERL3 was also upregulated in LUAD tissues compared with adjacent tissues from individuals. DERL3 was preliminarily found to be associated with immune infiltration via the TIMER database. Further, the t-SNE map revealed that DERL3 was predominantly enriched in plasma cells of the B cell population. It was demonstrated that DERL3 high-expressed patients presented significantly worse response to chemotherapy and immunotherapy. GSEA and KEGG results indicated that DERL3 was positively correlated with B cell activation and unfolded protein response (UPR). Conclusion: Our findings indicated that DERL3 might play an essential role in the endoplasmic reticulum-associated degradation (ERAD) process in LUAD. Moreover, DERL3 may act as a promising immune biomarker, which could predict the efficacy of immunotherapy in LUAD.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Prognóstico , Estresse do Retículo Endoplasmático/genética , Degradação Associada com o Retículo Endoplasmático , Regulação Neoplásica da Expressão Gênica , Biomarcadores/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo
16.
Cell Death Discov ; 8(1): 360, 2022 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-35963847

RESUMO

Non-small cell lung cancer (NSCLC) is a primary histological subtype of lung cancer with increased morbidity and mortality. K+ channels have been revealed to be involved in carcinogenesis in various malignant tumors. However, TWIK-related acid-sensitive potassium channel 1 (TASK-1, also called KCNK3), a genetic member of K2P channels, remains an enigma in lung adenocarcinoma (LUAD). Herein, we investigated the pathological process of KCNK3 in proliferation and glucose metabolism of LUAD. The expressions of KCNK3 in LUAD tissues and corresponding adjacent tissues were identified by RNA sequencing, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry. Gain and loss-of-function assays were performed to estimate the role of KCNK3 in proliferation and glucose metabolism of LUAD. Additionally, energy metabolites of LUAD cells were identified by targeted metabolomics analysis. The expressions of metabolic molecules and active biomarkers associated with AMPK-TXNIP signaling pathway were detected via western blot and immunofluorescence. KCNK3 was significantly downregulated in LUAD tissues and correlated with patients' poor prognosis. Overexpression of KCNK3 largely regulated the process of oncogenesis and glycometabolism in LUAD in vitro and in vivo. Mechanistic studies found that KCNK3-mediated differential metabolites were mainly enriched in AMPK signaling pathway. Furthermore, rescue experiments demonstrated that KCNK3 suppressed proliferation and glucose metabolism via activation of the AMPK-TXNIP pathway in LUAD cells. In summary, our research highlighted an emerging role of KCNK3 in the proliferative activity and glycometabolism of LUAD, suggesting that KCNK3 may be an optimal predictor for prognosis and a potential therapeutic target of LUAD.

17.
J Colloid Interface Sci ; 627: 804-814, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35901560

RESUMO

The rational design of ultrathin and few-layered structures for three-dimensional MoS2 nanospheres is crucial for achieving attractive lithium-ion batteries (LIBs). Herein, hollow nanospheres constructed by ultrafine and few-layered MoS2 homogeneously incorporated in N-doped amorphous carbon (HUF-MoS2/NC) have been successfully synthesized as high-performance anode for LIBs. Using Mo-glycerol spheres as templates and dopamine hydrochloride as coordination ligands, hollow Mo-glycerol-polydopamine precursors are formed with Mo-containing groups which are surrounded by organic carbon species. Consequently, the MoS2 is confined to the nanoscale and grows partially amorphous fragments while being uniformly embedded in NC. This unique architecture can not only hinder the substantial restacking between MoS2 interlayers, offering more active sites, but also vastly enhance the electrical conductivity and relieve the mechanical stress ascribed to volume changes. As a result, the HUF-MoS2/NC composite anode exhibits excellent cyclic stability (980mAhg-1 after 300 cycles at 0.2Ag-1) and superior rate performance (498mAhg-1 at 5.0Ag-1) for LIBs.

18.
Micromachines (Basel) ; 12(9)2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34577689

RESUMO

In order to explore the dynamic characteristics of the linear-arch beam tri-stable piezoelectric energy harvester (TPEH), a magnetic force model was established by the magnetic dipole method, and the linear-arch composite beam nonlinear restoring force model was obtained through experiments. Based on the Euler-Bernoulli beam theory, a system dynamic model is established, and the influence of the horizontal distance, vertical distance and excitation acceleration of magnets on the dynamic characteristics of the system is simulated and analyzed. Moreover, the correctness of the theoretical results is verified by experiments. The results show that the system can be mono-stable, bi-stable and tri-stable by adjusting the horizontal or vertical spacing of the magnets under proper excitation. The potential well of the system in the tri-stable state is shallow, and it is easier to achieve a large-amplitude response. Increasing the excitation level is beneficial for the large-amplitude response of the system. This study provides theoretical guidance for the design of linear-arch beam TPEH.

19.
Micromachines (Basel) ; 12(8)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34442617

RESUMO

To improve the energy harvesting performance of an energy harvester, a novel bistable piezoelectric energy harvester with variable potential well (BPEH-V) is proposed by introducing a spring to the external magnet from a curve-shaped beam bistable harvester (CBH-C). First, finite element simulation was performed in COMSOL software to validate that the curved beam configuration was superior to the straight beam in power generation performance, which benefits energy harvesting. Moreover, the nonlinear magnetic model was obtained by using the magnetic dipoles method, and the nonlinear restoring force model of the curve-shaped beam was acquired based on fitting the experimental data. The corresponding coupled governing equations were derived by using generalized Hamilton's principle, the dynamic responses were obtained by solving the coupling equations with the ode45 method. Finally, the numerical simulations showed that the proposed harvester can make interwell oscillations easier due to the spring being efficiently introduced to pull down the potential barrier compared with the conventional bistable harvester. Spring stiffness has a great impact on characteristics of the system, and a suitable stiffness contributes to realize large-amplitude interwell oscillations over a wide range of excitation, especially in the low excitation condition.

20.
J Colloid Interface Sci ; 587: 260-270, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33360899

RESUMO

In order to cope with the problem of insufficient lithium metal reserves, sodium ion batteries (SIBs) are proposed and extensively studied for the next-generation batteries. In our work, hierarchical NiCo2Se4 nanoneedles/nanosheets are deposited on the skeleton of N-doped three dimensional porous graphene (NPG) by a convenient solvothermal method and subsequent gas-phase selenization process. Compared with NiCo2Se4 powder, the optimized NiCo2Se4/N-doped porous graphene composite (denoted as NCS@NPG) as self-supporting anode exhibits the excellent electrode activity for SIBs, with a specific capacity of 500 mAh/g and 257 mAh/g at a current density of 0.2 A/g and 6.4 A/g, respectively. The high specific capacity as well as rate capacity can be attributed to the three-dimensional graphene skeleton with high electrical conductivity and pore structure, which provides convenient ion and electron transmission channels.

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