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1.
J Phys Chem Lett ; 15(18): 4799-4805, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38666898

RESUMO

We investigate the role of the black-phosphorus-based n-p (BP-np) junction modulated by linearly polarized light (LPL) in governing the quantum transport behaviors. Following the analysis of the band structures, we find that the LPL can adjust the gap between the conduction and valence bands by reducing the impact of momentum mismatch caused by the band gap. In addition, LPL can also eliminate the angle dependence of transmission. This means that for BP with a fixed band gap, the transmission-forbidden region can be reduced and the transmission probability can be increased by applying LPL modulation of the band gap to achieve all-angle perfect transmission, i.e., super-Klein tunneling (SKT). Our investigation also found that the SKT is robust to different incident energies, resulting in a larger conductance platform. These findings could be useful for the development and application of optical-like electronic devices.

2.
J Clin Ultrasound ; 52(3): 295-304, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38143429

RESUMO

PURPOSE: This study explored the correlation between inflammatory markers and ulcerative plaques based on carotid doppler ultrasound (CDU) in individuals with acute ischemic stroke (AIS). METHODS: A total of 202 cases diagnosed with AIS associated with atherosclerotic plaque (AP) in the carotid artery were enrolled in this research. Collecting clinical baseline data, laboratory data (such as the complete blood count) and imaging data (CDU and Brain magnetic resonance imaging [MRI]). Then the correlation between Systemic immune-inflammation index (SII, SII = P N/L, where P, N, and L were the peripheral blood platelet, neutrophil and lymphocyte counts, respectively), the shape and position of AP, the degree of carotid artery stenosis, and the presence of ulcerative plaques. Cutoff values were determined accordingly. RESULTS: SII and high sensitivity CRP (hs-CRP) were independent risk factors for the presence of vulnerable carotid plaques. SII, type A plaque, plaque above carotid bifurcation, and severe carotid stenosis were independent risk factors for the presence of ulcerative plaque. The AUC value, the sensitivity, specificity, the best cutoff value of SII in predicting the presence of ulcerative plaque was 0.895, 93.3%, 89.2%, and 537.4 (109 /L), respectively. CONCLUSION: SII at admission was found to be independently associated with the presence of AIS with vulnerable plaque, especially ulcerative plaques. Moreover, plaque ulceration was more likely to form when the area of higher plaque thickness was located in the upstream arterial wall of maximum plaque thickness (WTmax), plaque was above the carotid bifurcation and severe carotid stenosis.


Assuntos
Estenose das Carótidas , AVC Isquêmico , Placa Aterosclerótica , Acidente Vascular Cerebral , Humanos , Placa Aterosclerótica/complicações , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/patologia , Estenose das Carótidas/complicações , Estenose das Carótidas/diagnóstico por imagem , AVC Isquêmico/complicações , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/patologia , Artérias Carótidas/patologia , Inflamação/diagnóstico por imagem , Inflamação/complicações , Inflamação/patologia , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem
3.
Nanomaterials (Basel) ; 13(14)2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37513128

RESUMO

The potential application of borophene as a sensing material for gas-sensing devices is investigated in this work. We utilize density functional theory (DFT) to systematically study the adsorption mechanism and sensing performance of χ3-borophene to search for high-sensitivity sensors for minor pollutant gases. We compare the results to those for two Pmmn borophenes. The first-principles calculations are used to analyze the sensing performance of the three different borophenes (2 Pmmn borophene, 8 Pmmn borophene, and χ3-borophene) on five leading harmful gases (CO, NH3, SO2, H2S, and NO2). The adsorption configuration, adsorption energy, and electronic properties of χ3-borophene are investigated. Our results indicate that the mechanism of adsorption on χ3-borophene is chemisorption for NO2 and physisorption for SO2 and H2S. The mode of adsorption of CO and NH3 on χ3-borophene can be both physisorption and chemisorption, depending on the initially selected sites. Analyses of the charge transfer and density of states show that χ3-borophene is selective toward the adsorption of harmful gases and that N and O atoms form covalent bonds when chemisorbed on the surface of χ3-borophene. An interesting phenomenon is that when 8 Pmmn borophene adsorbs SO2, the gas molecules are dismembered and strongly adsorb on the surface of 8 Pmmn borophene, which provides a way of generating O2 while adsorbing harmful substances. Overall, the results of this work demonstrate the potential applications of borophene as a sensing material for harmful gas sensing or removal.

4.
Nanomaterials (Basel) ; 13(9)2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37177096

RESUMO

One of the critical techniques for developing hydrogen storage applications is the advanced research to build novel two-dimensional materials with significant capacity and effective reversibility. In this work, we perform first-principles unbiased structure search simulations to find a novel AsC5 monolayer with a variety of functionally advantageous characteristics. Based on theoretical simulations, the proposed AsC5 has been found to be energetically, dynamically, and thermally stable, supporting the viability of experiment. Since the coupling between H2 molecules and the AsC5 monolayer is quite weak due to physisorption, it is crucial to be enhanced by thoughtful material design. Hydrogen storage capacity can be greatly enhanced by decorating the AsC5 monolayer with Li atoms. Each Li atom on the AsC5 substrate is shown to be capable of adsorbing up to four H2 molecules with an advantageous average adsorption energy (Ead) of 0.19 eV/H2. The gravimetric density for hydrogen storage adsorption with 16Li and 64 H2 of a Li-decorated AsC5 monolayer is about 9.7 wt%, which is helpful for the possible application in hydrogen storage. It is discovered that the desorption temperature (TD) is much greater than the hydrogen critical point. Therefore, such crucial characteristics make AsC5-Li be a promising candidate for the experimental setup of hydrogen storage.

5.
Front Cardiovasc Med ; 9: 1001269, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36386316

RESUMO

Objectives: This study aimed to determine whether texture analysis (TA) and machine learning-based classifications can be applied in differential diagnosis of cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM) using non-contrast cine cardiac magnetic resonance (CMR) images. Methods: In this institutional review board-approved study, we consecutively enrolled 167 patients with CA (n = 85), HCM (n = 82), and 84 patients with normal CMR served as controls. All cases were randomized into training [119 patients (70%)] and validation [48 patients (30%)] groups. A total of 275 texture features were extracted from cine images. Based on regression analysis with the least absolute shrinkage and selection operator (LASSO), nine machine learning models were established and their diagnostic performance determined. Results: Nineteen radiomics texture features derived from cine images were used to differentiate CA and HCM. In the validation cohort, the support vector machine (SVM), which had an accuracy of 0.85, showed the best performance (MCC = 0.637). Gray level non-uniformity (GLevNonU) was the single most effective feature. The combined model of radiomics texture features and conventional MR metrics had superior discriminatory performance (AUC = 0.89) over conventional MR metrics model (AUC = 0.79). Moreover, results showed that GLevNonU levels in HCM patients were significantly higher compared with levels in CA patients and control groups (P < 0.001). A cut-off of GLevNonU ≥ 25 was shown to differentiate between CA and HCM patients, with an area under the curve (AUC) of 0.86 (CI:0.804-0.920). Multiple comparisons tests showed that GLevNonU was significantly greater in LGE+, relative to LGE-patient groups (CA+ vs. CA- and HCM+ vs. HCM-, P = 0.01, 0.001, respectively). Conclusion: Machine learning-based classifiers can accurately differentiate between CA and HCM on non-contrast cine images. The radiomics-MR combined model can be used to improve the discriminatory performance. TA may be used to assess myocardial microstructure changes that occur during different stages of cardiomyopathies.

6.
Front Neurol ; 13: 959531, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36158955

RESUMO

Vulnerable carotid plaque is closely related to the occurrence of Ischemic stroke. Therefore, accurate and rapid identification of the nature of carotid plaques is essential. AS is a chronic immune inflammatory process. Systemic immune-inflammation index (SII) is a novel index of immune inflammation obtained from routine whole blood cell count analysis, which comprehensively reflects the state of inflammation and immune balance in the body. This study sought to explore the relationship between SII level and carotid plaque vulnerability, plaque composition characteristics, and acute ischemic stroke (AIS) severity. A total of 131 patients diagnosed with AIS presenting with a carotid atherosclerotic plaque were enrolled in this study. Using carotid ultrasound (CDU) to assess the carotid-responsible plaque properties, we divided the patients into stable plaques group and vulnerable plaques group, and analyzed the correlation between SII levels and plaque vulnerability. And we further analyzed to evaluate the correlation between high SII levels and plaque characteristics and AIS severity. In addition, Cohen's Kappa statistics was used to detect the consistency of Carotid ultrasound (US) and cervical High-resolution magnetic resonance imaging (HRMRI) in evaluating plaque vulnerability. The findings showed that the vulnerable group had higher levels of SII compared with the stable group. The high SII group had more vulnerable plaques and a high frequency of plaque fibrous cap rupture compared with the low SII group. Logistic analysis showed that a high SII level was an independent risk factor for vulnerable plaques (odds ratio [OR] = 2.242) and plaque fibrous cap rupture (OR=3.462). The results also showed a high consistency between Carotid US and HRMRI methods in the assessment of plaque vulnerability [Cohen's kappa value was 0.89 (95% CI = 0.78-0.97)] and the level of SII was positively associated with NIHSS score (r = 0.473, P < 0.001). Our study suggests that elevated levels of SII may have adverse effects on the vulnerability of carotid plaques, especially in stroke patients with vulnerable plaques with ruptured fibrous caps, which may aggravate the severity of AIS.

7.
Front Neurol ; 13: 848545, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35923825

RESUMO

Background: Early mobilization in the intensive care unit (ICU) is a hotspot. This study aims to provide a bibliometric perspective of the progress in this field. Methods: We extracted publications on ICU early mobilization published in the Web of Science Core Collection database from 2000 to 2021. VOSviewer was used to construct co-occurrence and co-citation relationships for authors, references, and keywords; Citespace was used to visualize knowledge mapping of subject categories, countries, and keywords with the strongest citation bursts. Results: A total of 4,570 publications were analyzed, with a steady increase in publications in the field of ICU early mobilization. From a macro perspective, research on ICU early mobilization involves multidisciplinary involvement, including critical care medicine, neurology, and nursing; as for the meso perspective, the United States is the major contributor. Needham DM and Schweickert WD are the key researchers in this field. Moreover, the core journal is Critical Care Medicine, with the most publications and citations. The microscopic level, dominated by references and keywords, illustrates that the hotspot and frontier of research on ICU early mobilization focus on ICU-acquired weakness, delirium, the prognosis of critical illness, and severe COVID-19. Conclusion: This study presents a research landscape of ICU early mobilization from different perspectives. These findings will contribute to a better understanding of the current state of research in critical care medicine and provide the available information for future research ideas.

8.
J Clin Ultrasound ; 50(7): 905-912, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35801515

RESUMO

Ischemic stroke (IS) exhibits a high disability rate, mortality, and recurrence rate, imposing a serious threat to human survival and health. Its occurrence is affected by various factors. Although the previous research has demonstrated that the occurrence of IS is mainly associated with lumen stenosis caused by carotid atherosclerotic plaque (AP), recent studies have revealed that many patients will still suffer from IS even with mild carotid artery lumen stenosis. Blood supply disturbance causes 10% of IS to the corresponding cerebral blood supply area caused by carotid vulnerable plaque. Thrombus blockage of distal branch vessels caused by rupture of vulnerable carotid plaque is the main cause of ischemic stroke. Therefore, how to accurately evaluate vulnerable plaque and intervene as soon as possible is a problem that needs to be solved in clinic. The vulnerability of plaque is determined by its internal components, including thin and incomplete fibrous cap, necrotic lipid core, intra-plaque hemorrhage, intra-plaque neovascularization, and ulcerative plaque formation. The development of imaging technology enables the routine detection of AP vulnerability. By analyzing the pathological changes, characteristics, and formation mechanism of carotid plaque vulnerability, this article aims to explore the modern imaging methods which can be used to identify plaque composition and plaque vulnerability to provide a reference basis for disease diagnosis and differential diagnosis.


Assuntos
Estenose das Carótidas , AVC Isquêmico , Placa Aterosclerótica , Artérias Carótidas/patologia , Estenose das Carótidas/diagnóstico por imagem , Constrição Patológica/patologia , Humanos , Imageamento por Ressonância Magnética , Placa Aterosclerótica/diagnóstico , Fatores de Risco
9.
Front Neurosci ; 16: 885209, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35720730

RESUMO

Vulnerable carotid plaques are closely related to the occurrence of ischemic stroke. Therefore, accurate and rapid identification of the nature of carotid plaques is essential. This study aimed to determine whether texture analysis based on a vascular ultrasound can be applied to identify vulnerable plaques. Data from a total of 150 patients diagnosed with atherosclerotic plaque (AP) by carotid ultrasound (CDU) and high-resolution magnetic resonance imaging (HRMRI) were collected. HRMRI is the in vivo reference to assess the nature of AP. MaZda software was used to delineate the region of interest and extract 303 texture features from ultrasonic images of plaques. Following regression analysis using the least absolute shrinkage and selection operator (LASSO) algorithm, the overall cohort was randomized 7:3 into the training (n = 105) and testing (n = 45) sets. In the training set, the conventional ultrasound model, the texture feature model, and the conventional ultrasound-texture feature combined model were constructed. The testing set was used to validate the model's effectiveness by calculating the area under the curve (AUC), accuracy, sensitivity, and specificity. Based on the combined model, a nomogram risk prediction model was established, and the consistency index (C-index) and the calibration curve were obtained. In the training and testing sets, the AUC of the prediction performance of the conventional ultrasonic-texture feature combined model was higher than that of the conventional ultrasonic model and the texture feature model. In the training set, the AUC of the combined model was 0.88, while in the testing set, AUC was 0.87. In addition, the C-index results were also favorable (0.89 in the training set and 0.84 in the testing set). Furthermore, the calibration curve was close to the ideal curve, indicating the accuracy of the nomogram. This study proves the performance of vascular ultrasound-based texture analysis in identifying the vulnerable carotid plaques. Texture feature extraction combined with CDU sonogram features can accurately predict the vulnerability of AP.

10.
J Immunol Res ; 2022: 1161931, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35600043

RESUMO

Background: Globally, non-small-cell lung cancer (NSCLC) is one of the most prevalent tumors. Various studies have investigated its etiology, but the molecular mechanism of NSCLC has not been elucidated. Methods: The GSE19804, GSE118370, GSE19188, GSE27262, and GSE33532 microarray datasets were obtained from the Gene Expression Omnibus (GEO) database for the identification of genes involved in NSCLC development as well as progression. Then, the identified differentially expressed genes (DEGs) were subjected to functional enrichment analyses. The protein-protein interaction (PPI) network was built after which module analysis was conducted via the Search Tool for Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape. There were 562 DEGs: 98 downregulated genes and 464 upregulated. These DEGs were established to be enriched in p53 signaling pathway, transendothelial leukocyte migration, cell adhesion molecules, contractions of vascular smooth muscles, coagulation and complement cascades, and axon guidance. Assessment of tumor immunity was performed to determine the roles of hub genes. Results: There were 562 dysregulated genes, while 12 genes were hub genes. NUF2 was established to be a candidate immunotherapeutic target with potential clinical implications. The 12 hub genes were highly enriched in the p53 signaling pathway, the cell cycle, progesterone-associated oocyte maturation, cellular senescence, and oocyte meiosis. Survival analysis showed that NUF2 is associated with NSCLC occurrence, invasion, and recurrence. Conclusion: The NUF2 gene discovered in this study helps us clarify the pathomechanisms of NSCLC occurrence as well as progression and provides a potential diagnostic and therapeutic target for NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Proteínas de Ciclo Celular , Neoplasias Pulmonares , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Proteínas de Ciclo Celular/genética , Biologia Computacional , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Prognóstico , Proteína Supressora de Tumor p53/genética
11.
J Phys Condens Matter ; 34(8)2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34787103

RESUMO

We investigate the quantum transmission through the n-p-n heterojunction of massive 8-Pmmnborophene. It is found that the Dirac mass of the electron interacts nontrivially with the anisotropy of the 8-Pmmnborophene, leading to the occurrence of new transmission behaviors in this n-p-n heterojunction. Firstly, the effective energy range of nonzero transmission can be reduced but deviates from the mass amplitude, which induces the further controllability of the transmission property. Secondly, even if the equal-energy surfaces in the p and n parts do not encounter in thek-space, finite transmission is allowed to occur as well. In addition, the existence of Dirac mass can change the reflection manner from the retroreflection to the specular reflection under appropriate conditions. The findings in this work can be helpful in describing the quantum transport properties of the heterojunction based on 8-Pmmnborophene.

12.
Int Immunopharmacol ; 100: 108073, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34454290

RESUMO

BACKGROUND: Investigating anti-oxidant therapies that lead to the diminution of oxidative injury is priority in clinical. We herein aimed to explore whether and how Licochalcone B (Lico B) act as an anti-oxidant in the stroke model. METHODS: Middle cerebral artery occlusion (MCAO) was constructed as stroke model and exposed to various doses of Lico B. Behavioral tests and neurological behavior status were detected for neurological function examination. Histological staining was used for evaluating cerebral injury, and neuronal apoptosis or damage. Levels of oxidative stress and inflammation were also assessed by biochemical analysis and expression analysis. Nrf2 knockdown induced by lentiviral vector was used for the research on mechanism. RESULTS: Lico B had improvement effects on cerebral infarction size, memory impairments, and neurological deficits after MCAO. Histological evaluation also revealed the amelioration of neuronal injury and apoptosis by Lico B, along with down-regulation of apoptosis-related proteins. Additionally, Lico B rescued the down-regulation of BDNF and NGF after MCAO. Moreover, Lico B suppressed the oxidative stress and inflammation, manifesting as the enhancement of SOD, GSH and IL-4, but the decline of MDA, iNOS, and TNF-α. Finally, Nrf2 knockdown reversed the Lico B-caused improvement in neuronal injury, apoptosis and oxidative stress levels. CONCLUSIONS: The present study revealed the neuroprotective effects of Lico B in MCAO rats. Importantly, we proposed a potential mechanism that Lico B activated the Nrf2 pathway, thereby acting as anti-oxidant to attenuate neuronal injury and apoptosis after stroke. The proposed mechanism provided an encouraging possibility for anti-oxidant therapy of stroke.


Assuntos
Antioxidantes/farmacologia , Chalconas/farmacologia , Infarto da Artéria Cerebral Média/tratamento farmacológico , Fator 2 Relacionado a NF-E2/agonistas , Animais , Antioxidantes/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/imunologia , Chalconas/uso terapêutico , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Hipocampo/efeitos dos fármacos , Hipocampo/imunologia , Hipocampo/patologia , Humanos , Infarto da Artéria Cerebral Média/imunologia , Infarto da Artéria Cerebral Média/patologia , Masculino , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/imunologia , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/imunologia , Ratos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/imunologia
13.
J Phys Condens Matter ; 33(21)2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33588382

RESUMO

We investigate the effect of quantum interference on the Andreev reflections (ARs) induced by Majorana bound states (MBSs), by considering their additional coupling via a quantum-dot molecule. It is found that due to the direct and indirect couplings of MBSs, a quantum ring is constructed in this system. Consequently, the interference effect makes important contribution to the ARs, especially in the presence of the local magnetic flux. All the results are manifested as the tight dependence of the differential conductance and Fano factors on the magnetic flux phase factor, dot-MBS couplings, and the dot level, respectively. Moreover, at the zero-bias limit, the magnitudes of the Fano factors and their relation can be efficiently altered by the interference properties. We believe that quantum interference is important for manipulating the Andreev reflection behaviors of the MBSs.

14.
Opt Express ; 28(23): 35168-35178, 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33182968

RESUMO

We theoretically investigate the frustrated double ionization (FDI) of Ar atoms with counter-rotating two-color circular (CRTC) laser fields using the three-dimensional (3D) classical ensemble method. Our results show that the FDI probability depends upon the intensity ratio of the CRTC laser fields. The FDI event accompanied with the recollision excitation with subsequent ionization is prevalent and three pathways exist in FDI processes driven by CRTC laser fields. The momentum distribution of a recaptured electron at the ionization time after recollision indicates that the momentum being close to the vector potential is a necessary condition for FDI events to occur. In addition, the recaptured electron most probably transitions to a Rydberg state of which the quantum number is ten in the CRTC fields.

15.
Kaohsiung J Med Sci ; 36(10): 793-798, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32492286

RESUMO

Hepatocellular carcinoma (HCC) is one of the common malignant tumors with poor overall prognosis. As a tumor suppressor, the function of miR-559 in HCC is not clear. In this study, quantitative real-time PCR was carried out to measure the expression of miR-559 in HCC cell lines. The effects of miR-559 on HCC cell proliferation, migration, and invasion were evaluated through a series of functional assays. The mechanism through which miR-559 regulates HCC cells was investigated by dual-luciferase reporter assay and functional experiments. The results revealed that miR-559 expression was low in HCC cell lines. Upregulation of miR-559 suppressed HCC cell proliferation, migration, and invasion. Dual-luciferase reporter assay confirmed Golgi membrane protein 73 (GP73) as a target gene of miR-559. Moreover, miR-559 could negatively regulate GP73 expression in HCC cells. These results demonstrated that low-level expression of miR-559 was associated with HCC, and overexpression of miR-559 could inhibit HCC cell growth and invasion via targeting GP73.


Assuntos
Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Proteínas de Membrana/metabolismo , MicroRNAs/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Proliferação de Células/fisiologia , Regulação Neoplásica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Proteínas de Membrana/genética , MicroRNAs/genética
16.
Opt Express ; 28(6): 8560-8573, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32225478

RESUMO

We theoretically study the transport properties in a one-dimensional photonic lattice influenced by the presence of side-coupled P T-symmetric non-Hermitian defects. The P T symmetry is manifested as the complex potentials on the defects and the complex defect-lattice couplings, respectively. These two mechanisms are found to induce the Fano effect in the transport processes, with the different characteristics of it. Next, if the complex potentials and defect-lattice couplings co-exist, the Fano effect will be achieved more efficiently. However, further enhancing either of them can weaken the Fano interference seriously. Our findings reveal the physical essence of the Fano effect on the P T-symmetric non-Hermitian defects, and the results can provide insights into the engineering and dynamical control of Fano resonances in non-Hermitian photonic structures.

17.
J Phys Condens Matter ; 32(16): 165401, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-31846955

RESUMO

By introducing the next-nearest-neighboring (NNN) intersite coupling, we investigate the eigenenergies of the [Formula: see text]-symmetric non-Hermitian Su-Schrieffer-Heeger (SSH) model with two conjugated imaginary potentials at the end sites. It is found that with the strengthening of NNN coupling, the particle-hole symmetry is destroyed. As a result, the bonding band is first narrowed and then undergoes the top-bottom reversal followed by the its width's increase, whereas the antibonding band is widened monotonously. In this process, the topological state extends into the topologically-trivial region, and its energy departs from the energy zero point, accompanied by the emergence of one new topological state in this region. All these results give rise to the complication of the topological properties and the manner of [Formula: see text]-symmetry breaking. It can be concluded that the NNN coupling takes important effects to the change of the topological properties of the non-Hermitian SSH system.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(12): 3315-8, 2011 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-22295785

RESUMO

Ce(1-x)(Fe(0.5)La(0.5))xO(2-delta) solid solutions were obtained via hydrothermal method. The structure of the solid solutions and the cell parameters were characterized by XRD analysis technique, the electron transition properties and doping effectswere measured by UV-Vis diffraction spectrum and Raman spectrum technique. XRD results showed that Ce(1-x)(Fe(0.5)La(0.5))xO(2-delta) id solutions exhibited cubic fluorite structure till the doping content increased to 0.30. Tiny Fe2O3 phase was observed when x = 0.30. The particle size was kept nanoscaled, and location of different kind of doping ions in CeO2 lattice was discussed. By increasing the doping content, the cell parameter was kept increasing gradually till x = 0.18, then it remained almost constant. The UV-Vis diffraction spectrum analysis showed that the absorption threshold edge redshifted, the band gap energy decreased with increasing the doping content. The valence of Fe ions in the lattice of CeO2 was +3. The F2g Raman mode also showed a downshift, and the peak gradually became broader, which further proved the influence of the dopant.

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