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1.
Molecules ; 28(24)2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38138435

RESUMO

Currently, two-dimensional (2D) materials with intrinsic antiferromagnetism have stimulated research interest due to their insensitivity to external magnetic fields and absence of stray fields. Here, we predict a family of stable transition metal (TM) borides, TMB12 (TM = V, Cr, Mn, Fe) monolayers, by combining TM atoms and B12 icosahedra based on first-principles calculations. Our results show that the four TMB12 monolayers have stable antiferromagnetic (AFM) ground states with large magnetic anisotropic energy. Among them, three TMB12 (TM=V, Cr, Mn) monolayers display an in-plane easy magnetization axis, while the FeB12 monolayer has an out-of-plane easy magnetization axis. Among them, the CrB12 and the FeB12 monolayers are AFM semiconductors with band gaps of 0.13 eV and 0.35 eV, respectively. In particular, the AFM FeB12 monolayer is a spin-polarized AFM material with a Néel temperature of 125 K. Moreover, the electronic and magnetic properties of the CrB12 and the FeB12 monolayers can be modulated by imposing external biaxial strains. Our findings show that the TMB12 monolayers are candidates for designing 2D AFM materials, with potential applications in electronic devices.

2.
Nanoscale ; 15(46): 18745-18752, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-37955150

RESUMO

To realize the quantum anomalous Hall (QAH) effect in two-dimensional (2D) intrinsic magnetic materials, which combines insulating bulk states and metallic edge channel states, is still challenging in experiment. Here, based on first-principles calculations, we predicted two stable kagome-latticed QAH insulators: Cr3Se4 and Fe3S4 monolayers, with the Chern number C = 1. It is found that both structures exhibit a large magnetic anisotropy energy and sizable band gaps, and a topological phase transition from C = -1 to C = 1 occurs when the magnetization orientation changes from the z-axis to the -z-axis. Remarkably, the non-trivial topological properties are robust against biaxial strains of up to ±6%. Furthermore, a variable high Chern number of C = 2 or C = 3 can be observed by stacking two or three layers of the QAH monolayer with an MoS2 insulator. Our results signify that such layered kagome materials can be promising platforms for exploring novel QAH physics.

3.
Oncol Lett ; 26(6): 546, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38020306

RESUMO

Preoperative neoadjuvant therapy is widely used in cancer treatment; however, its efficacy in different subtypes of non-small cell lung cancer (NSCLC) is unknown. The present study compared the clinical efficacy of preoperative neoadjuvant therapy for two major NSCLC subtypes. Patients with NSCLC who underwent preoperative neoadjuvant therapy between January 2016 and August 2022 were reviewed. Patients were stratified according to histology and treatment strategy. Retrospective analysis was performed by comparing the basic clinical characteristics of the patients, clinicopathological characteristics of the tumors, imaging data and pathological responses to treatment. A total of 36 cases of lung squamous cell carcinoma (LUSC) and 31 cases of lung adenocarcinoma (LUAD) were included. After neoadjuvant chemotherapy combined with immunotherapy, the pathological response rates were higher for patients with LUSC than LUAD, but there was no statistically significant difference between the two subgroups (P=0.06). However, the pathological complete response rates after neoadjuvant chemotherapy combined with immunotherapy were significantly higher for LUSC than those after chemotherapy alone (P=0.01). These preliminary findings suggested that preoperative chemotherapy combined with immunotherapy could improve the pathological response of patients, particularly in those with LUSC. The present study provided new insights into the treatment of NSCLC.

4.
Int J Biol Sci ; 19(14): 4442-4456, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37781041

RESUMO

As the most common malignancy from mediastinum, the metabolic reprogramming of thymoma is important in its development. Nevertheless, the connection between the metabolic map and thymoma development is yet to be discovered. Thymoma was categorized into three subcategories by unsupervised clustering of molecular markers for metabolic pathway presentation in the TCGA dataset. Different genes and functions enriched were demonstrated through the utilization of metabolic Gene Ontology (GO) analysis. To identify the main contributors in the development of thymic malignancy, we utilized Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The prognosis of thymoma was evaluated by screening the essential pathways and genes using GSVA scores and machine learning classifiers. Furthermore, we integrated the transcriptomics findings with spectrum metabolomics investigation, detected through LC-MS/MS, in order to establish the essential controller network of metabolic reprogramming during thymoma progression. The thymoma prognosis is related to glycosphingolipid biosynthesis-lacto and neolacto series pathway, of what high B3GNT5 indicate poor survival. The investigation revealed that glycosphingolipid charts have a significant impact on metabolic dysfunction and could potentially serve as crucial targets in the clinical advancement of metabolic therapy.


Assuntos
Timoma , Neoplasias do Timo , Humanos , Timoma/genética , Cromatografia Líquida , Espectrometria de Massas em Tandem , Neoplasias do Timo/genética , Análise por Conglomerados
5.
Environ Sci Pollut Res Int ; 30(46): 102231-102243, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37665441

RESUMO

Global warming is currently an area of concern. Human activities are the leading cause of urban greenhouse gas intensification. Inversing the spatial distribution of carbon emissions at microscopic scales such as communities or controlling detailed planning plots can capture the critical emission areas of carbon emissions, thus providing scientific guidance for intracity low-carbon development planning. Using the Sino-Singapore Tianjin Eco-city as an example, this paper uses night-light images and statistical yearbooks to perform linear fitting within the Beijing-Tianjin-Hebei city-county region and then uses fine-scale data such as points of interest, road networks, and mobile signaling data to construct spatial characteristic indicators of carbon emissions distribution and assign weights to each indicator through the analytic hierarchy process. As a result, the spatial distribution of carbon emissions based on detailed control planning plots is calculated. The results show that among the selected indicators, the population distribution significantly influences carbon emissions, with a weight of 0.384. The spatial distribution of carbon emissions is relatively distinctive. The primary carbon emissions are from the Sino-Singapore Cooperation Zone due to its rapid urban construction and development. In contrast, carbon emissions from other areas are sparse, as there is mostly unused land under construction.

6.
Phys Chem Chem Phys ; 25(32): 21227-21235, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37539626

RESUMO

Multiferroic van der Waals (vdW) heterostructures (HSs) prepared by combining different ferroic materials offer an exciting platform for next-generation nanoelectronic devices. In this work, we investigate the magnetoelectric coupling properties of multiferroic vdW HSs consisting of a magnetic TMBr2 (TM = V-Ni) monolayer and a ferroelectric Ga2SSe2 monolayer using first-principles theory calculations. It is found that the magnetic orderings in the magnetic TMBr2 layers are robust and the band alignment of these TMBr2/Ga2SSe2 HSs can be altered by reversing the polarization direction of the ferroelectric layer. Among them, VBr2/Ga2SSe2 and FeBr2/Ga2SSe2 HSs can be switched from a type-I to a type-II semiconductor, which allows the generation of spin-polarized and unpolarized photocurrent. Besides, CrBr2/Ga2SSe2, CoBr2/Ga2SSe2 and NiBr2/Ga2SSe2 exhibit a type-II band alignment in reverse ferroelectric polarization states. Moreover, the magnetic configuration and band alignment of these TMBr2/Ga2SSe2 HSs can be further modulated by applying an external strain. Our findings suggest the potential of TMBr2/Ga2SSe2 HSs in 2D multiferroic and spintronic applications.

7.
Front Cardiovasc Med ; 10: 1112222, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36760573

RESUMO

Background: Immune checkpoint inhibitor-related myocarditis is the deadliest complication of immunotherapy. However, the underlying pathophysiological mechanisms of its occurrence and development remain unclear. Due to the long-term lack of effective early diagnosis and treatment options, it is of great significance to understand the pathophysiological mechanism of immune checkpoint inhibitor-related myocarditis. Methods: Tissue samples from three patients with immune checkpoint inhibitor-related myocarditis and three control tissue samples were collected for protein analysis. Differentially expressed proteins were screened out using quantitative proteomics technology based on TMT markers. Protein-protein interaction (PPI) and Gene Ontology (GO) functional enrichment analyses of cross-factors were subsequently performed. Combined with the PD-L1 subcellular organelle- level protein interaction network, we searched for hub proteins involved in immune checkpoint inhibitor-related myocarditis and explored potential drug sensitivity and disease correlation. Results: A total of 306 differentially expressed proteins were identified in immune checkpoint inhibitor-related myocarditis. Enrichment analysis showed that the differentially expressed proteins were closely related to mitochondrial metabolism. By analyzing mitochondria-related proteins and PD-L1-related proteins, we found four hub proteins, mammalian target of rapamycin (mTOR), Glycogen synthase kinase 3ß (GSK3ß), Protein tyrosine phosphatase non-receptor type 11 (PTPN11), and Mitofusin 2 (MFN2), indicating that they are closely related to immune checkpoint inhibitor-related myocarditis. Finally, we explored potential drugs for the treatment of immune checkpoint inhibitor-related myocarditis. Conclusion: Mitochondrial metabolism is involved in the process of immune checkpoint inhibitor-related myocarditis, and we identified four hub proteins, which may become new biomarkers for the early diagnosis and treatment of immune checkpoint inhibitor-related myocarditis.

8.
Nanoscale ; 15(5): 2079-2086, 2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36629033

RESUMO

Exploring two-dimensional (2D) ferromagnetic materials with a high transition temperature and large magnetic anisotropy is extremely essential for highly efficient spintronic applications. With the density functional theory method, we predicted planar hypercoordinate transition-metal borides, TMB12 (TM = Ti, V, Cr, Mn, Fe; B = boron), by the condensation of TM@B8 and B4 units. The results showed that these transition-metal borides possess superior thermal, dynamic and mechanical stabilities. Interestingly, the TMB12 monolayer with TM = (V, Cr) is confirmed as a robust ferromagnetic metal with a high Curie temperature of ∼335 K and ∼221 K, respectively. In addition, the system with TM = (Mn, Fe) is found to be an antiferromagnetic metal with a Néel temperature of ∼173 K and ∼91 K, respectively. In particular, large perpendicular magnetic anisotropy is identified for CrB12, MnB12, and FeB12 monolayers, around 198-623 µeV. Furthermore, four TMB12 (TM = Ti, V, Cr, Mn) systems are determined to be candidate catalysts for the hydrogen evolution reaction, with nearly zero free energy of hydrogen adsorption (ΔGH = -0.0003 to -0.03 eV). Our study highlighted potential 2D metal borides for spintronic devices and high efficiency electrochemical catalysts.

9.
Chemistry ; 29(7): e202202925, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36333274

RESUMO

Fixing nitrogen (N2 ) by electrosynthesis method has become a promising way to ammonia (NH3 ) production, nevertheless, developing electrocatalysts combining long-term stable and low-cost feathers are still a great challenge to date. Using comprehensive first-principles calculations, we herein investigate the potential of a new class of two-dimensional (2D) transition metal tri-borides (TMB3 s) as nitrogen reduction reaction (NRR) electrocatalysts, and explore the effect of magnetic orders on the NRR. Our results show that the TMB3 s can sufficiently activate N2 and convert it to NH3 . Particularly, TiB3 is identified as a high-efficiency catalyst for NRR because of its low limiting potential (-0.24 V) and good suppression of the competitive hydrogen evolution reaction (HER). For the first time, we present that these TMB3 s with various magnetic states exhibit different performances in the adsorption of N2 and NRR intermediates, and minor effect on activation of N2 . Besides, VB3 , CrB3 , MnB3 , and FeB3 monolayers possess the superior capacity to suppress surface oxidation via the self-activating process, which reduces * O/* OH into * H2 O under NRR electrochemical conditions, thus favoring the N2 electroreduction. This work paves the way for finding high-performance NRR catalysts for transition metal borides and pioneering the research of magnetic states effects in NRR.

10.
Front Surg ; 9: 973954, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36147693

RESUMO

Background: The subxiphoid approach has been widely used recently. However, there is little data focusing on neurological outcomes in patients with thymomatous myasthenia gravis (MG) who underwent subxiphoid thoracoscopic thymectomy. The purpose of this study was to compare the neurological outcomes of patients with thymomatous MG who underwent extended thymectomy with a subxiphoid or transthoracic approach 1 year postoperatively. Methods: The records of patients with Masaoka stage I and II thymomas who underwent extended thymectomy from January 2019 to December 2020 with tumor size less than 5 cm and thymomatous MG were retrospectively reviewed and evaluated. Neurological outcomes were measured by a quantitative myasthenia gravis score (QMGS), with a 2.3-point reduction in QMGS associated with improvement in clinical MG status. The clinical efficacy and variables affecting the outcomes were assessed using the Kaplan-Meier method and Cox proportional hazard regression analysis. Results: A total of 89 patients were included in the analysis, of which 44 had a subxiphoid approach and 45 had a trans-sternal approach. Mean QMGS decreased from 12 at initial diagnosis to 8.7 preoperatively and 5.6 at 12 months postoperatively in the subxiphoid group and from 12.1 to 8.9 to 6.0 in the transthoracic group. Thirteen patients (28.9%) who underwent the trans-sternal approach and 10 (22.7%) who underwent the subxiphoid approach did not have an improved clinical status compared with their preoperative status. The median time to clinical improvement was 3 months (95% CI, 2.15-3.85) for the subxiphoid approach and 6 months (95% CI, 5.54-6.46) for the trans-sternal approach. Univariate results showed that the subxiphoid approach was associated with a faster improvement in clinical status (HR = 1.701, 95% CI, 1.044-2.773, P < 0.05), and age ≦48 was associated with a faster improvement in clinical status (HR = 1.709, 95% CI, 1.044-2.799, P < 0.05). The multivariate model including age ≦48 (HR = 1.837, 95% CI, 1.093-3.086, P = 0.022) and the subxiphoid approach (HR = 1.892, 95% CI, 1.127-3.177, P = 0.016) was significantly associated with a faster improvement in clinical status. Conclusions: In patients with Masaoka stage I and II thymoma who underwent thymectomy, with tumor size less than 5 cm and thymomatous MG, age ≦48 years and the subxiphoid approach were associated with a rapid improvement in clinical status.

11.
Ying Yong Sheng Tai Xue Bao ; 33(9): 2493-2500, 2022 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-36131666

RESUMO

Quantitative assessment of livability within a city facilitates the identification of urban problems and targeted improvements to the environment. Available studies are mostly limited to static analysis of a particular phase. It is difficult to reveal the dynamic development state of cities at the micro level. Taking Sino-Singapore Tianjin Eco-city as an example, we established an evaluation index system for the livability of the eco-city from five dimensions, including environmental health, transportation convenience, urban security, facility convenience, and economic prosperity. Multi-source data from 2016 to 2020, including the remote sensing images, points of interest, and planning data, combined with the entropy method and the TOPSIS method were used to dynamically monitor the livability of the eco-city in a long-term series. The results showed that during the study period, the livability levels of different areas in the eco-city had strong spatial and temporal variations. Spatially, with the southern part of the Sino-Singapore Eco-city Cooperation Zone as the core, the overall livability was characterized by a high center and a low edge. The convenience of facilities, traffic convenience, and economic prosperity were characterized by a high center and a low edge. Urban security and environmental health showed the characteristics of low center and high edge. From 2016 to 2020, the livability improvement rate of the eco-city had gradually accelerated, with the the most obvious improvement in the southern part of the China-Singapore Cooperation Zone.


Assuntos
Meios de Transporte , China , Cidades , Entropia
12.
Nanoscale ; 14(34): 12491-12497, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-35983780

RESUMO

Topological and ferromagnetic features in two-dimensional (2D) materials have attracted considerable interest due to their excellent physical properties. 2D Weyl half-semimetals (WHSMs) are excellent platforms to study both properties. In this study, we predicted a 2D ferromagnetic WHSM, VB28, via first-principles calculations. The VB28 monolayer displays ultra-high thermodynamic stability. It has a couple of fully spin-polarized Weyl nodal points in the spin-down channel. The Weyl points are found to be protected by vertical mirror and antiunitary C2zT symmetries, which are robust against spin-orbit coupling (SOC) and in-plane strains. Our study not only discovers an intrinsic ferromagnetic 2D WSHM material with Weyl points around the Fermi level but also provides a potential candidate with good stability for spintronic devices.

13.
Nanomaterials (Basel) ; 12(16)2022 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-36014635

RESUMO

The geometrical structure, electronic and magnetic properties of B-endoped C60 (B@C60) ligand sandwich clusters, TM&(B@C60)2 (TM = V, Cr), and their one-dimensional (1D) infinite molecular wires, [TM&(B@C60)]∞, have been systematically studied using first-principles calculations. The calculations showed that the TM atoms can bond strongly to the pentagonal (η5-coordinated) or hexagonal rings (η6-coordinated) of the endoped C60 ligands, with binding energies ranging from 1.90 to 3.81 eV. Compared to the configurations with contrast-bonding characters, the η6- and η5-coordinated bonding is energetically more favorable for V-(B@C60) and Cr-(B@C60) complexes, respectively. Interestingly, 1D infinite molecular wire [V&(B@C60)-η6]∞ is an antiferromagnetic half-metal, and 1D [Cr&(B@C60)-η5]∞ molecular wire is a ferromagnetic metal. The tunable electronic and magnetic properties of 1D [TM&(B@C60)]∞ SMWs are found under compressive and tensile stains. These findings provide additional possibilities for the application of C60-based sandwich compounds in electronic and spintronic devices.

14.
Environ Res ; 204(Pt A): 111979, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34506782

RESUMO

The response of the denitrification community to long-term antibiotic exposure requires further investigation. Here, the significantly altered denitrifying community structure and function were observed by continuous exposure to 1 mg/L sulfamethoxazole (SMZ) or chlortetracycline (CTC) for 180 d in the expanded granular sludge bed reactors. Thaurea, positively correlated with SMZ and NO3- removal efficiency (NrE), was highly enriched in the SMZ-added reactor, while, Comamons and Acinetobacter were largely inhibited. The acute inhibited and then gradual-recovered NrE (87.17-90.38 %) was observed with highly expressed narG, indicating the adaptability of Thaurea to SMZ. However, the abundance of Thaurea and Comamonas greatly decreased, while Melioribacter and Acinetobacter were largely enriched in the CTC-added reactor. CTC created more serious and continuous inhibition of NO3- reduction (NrE of 64.53-66.95 %), with lowly expressed narG. Improved NO2- reduction capacity was observed in both reactors (70.16-95.42 %) with highly expressed nirS and nosZ, revealing the adaptability of NO2- reduction populations to antibiotics.


Assuntos
Clortetraciclina , Desnitrificação , Bactérias , Reatores Biológicos , Clortetraciclina/toxicidade , Nitrogênio , Esgotos , Sulfametoxazol/toxicidade
15.
ACS Appl Mater Interfaces ; 13(49): 58871-58884, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34859994

RESUMO

High-voltage high-nickel low-cobalt lithium layered oxide cathodes show great application prospects for lithium-ion batteries due to their low cost and high capacity. However, deterioration of the bulk structure and the electrode-electrolyte interface will significantly endanger the cycle life and thermal stability of the battery as the nickel content and voltage increase. We present here a lattice doping strategy to greatly improve the cell performance by doping a small dose of Ti (2 mol %) in LiNi0.6Co0.05Mn0.35O2. Through density functional theory calculations, we know that the diffusion energy barrier of Li+ decreases and the activation energy of surface lattice oxygen atom loss increases after Ti doping, thereby improving the rate performance and inhibiting the undesired phase transition. The battery in situ X-ray diffraction (XRD) pattern demonstrates that Ti doping tunes the H1-H2 phase-transition process from a two-phase reaction to a single-phase reaction and inhibits the undesired H2-H3 phase transition, minimizing the mechanical degradation. The variable temperature in situ XRD reveals delayed phase-transition temperature to improve thermal stability. These improvements can be attributed to Ti doping to passivate the reactivity of the layered oxide cathode, which is fundamentally related to the strong Ti-O bond and no unpaired electrons for Ti4+. This work provides valuable strategic guidelines for the use of high-voltage high-nickel low-cobalt cathodes in lithium-ion batteries.

16.
ACS Omega ; 6(20): 13426-13432, 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34056490

RESUMO

Building vertical van der Waals heterojunctions between two-dimensional layered materials has become a promising strategy for modulating the properties of two-dimensional materials. Herein, we investigate the electronic structures of non-twisted/twisted bilayer InSe/InSe and heterobilayer graphene/InSe (Gr/InSe) by employing density functional theory calculations. For twisted bilayer InSe/InSes, their interlayer distances and band gaps are almost identical but a bit larger than those of the AB-stacking one due to the spontaneous polarization. Differently, the band gaps of twisted Gr/InSe are found to vary with the rotation angles. Our results provide an effective way to tune the electronic properties of two-dimensional materials.

17.
Chemphyschem ; 22(9): 894-903, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33538388

RESUMO

Unlike graphene and other 2D materials, borophene is 2D polymorphic with diverse hexagonal holes (HHs)-triangles ratios and the concentrations of HHs are highly substrate dependent. Here, we systematically explored the evolution of boron cluster on Ag(111) surface, BN @Ag(111) (N=1∼36), to understand the nucleation of 2D boron sheet on metal surface. Our calculation showed that, with the size increasing, the structures of most stable BN clusters undergo an evolution from compact triangular lattice, such as double-chains or triple-chains, to the ones with mixed triangular-hexagonal lattices. The first single-HH appears at N=12 and the first double-HH appears at N=27. The stability of large BN clusters with mixed structures is derived from the charge transfer between triangular lattice and the HHs, as well as between the substrates and the BN clusters. Our results provide a deep understanding on the formation of small boron clusters in the initial nucleation stage of borophene growth.

18.
J Hazard Mater ; 405: 124366, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33301967

RESUMO

Antibiotics commonly exist in municipal, livestock and industrial wastewaters. However, the response of key microbiota performance in wastewater treatment plants to antibiotic exposure lacks systematic research. In this study, the short-term acute stress of four commonly used antibiotics (sulfamethoxazole, chlortetracycline, ciprofloxacin, and amoxicillin) on microbial denitrification performance was systematically investigated. All tested antibiotics exhibited the inhibitory effects in varying degrees by repeated addition for six cycles. The nitrate removal efficiencies (NrE) decreased to 7.98-26.80%, accompanied by the significant decrease of the expressed narG gene, by exposure to sulfamethoxazole, chlortetracycline or amoxicillin. Nitrite reduction was inhibited more severely than nitrate reduction, which was further verified by the low- or non-expressed nirS and nosZ genes. Furthermore, a higher antibiotic concentration made stronger inhibitory effect. Except for chlortetracycline, 2.09-6.80 times decrease of k value was commonly observed as concentration increased from 10 to 50 or 100 mg L-1. Even in a short period (24 h), antibiotics largely decreased the abundance of the dominant denitrifying bacterial genera (Thauera, Comamonas, etc.), while, some unclassified populations (Labrenzia, Longilinea, etc.) were enriched. This study provides theoretical researches on the microbial denitrification behaviors influenced by exposure to different antibiotics.


Assuntos
Desnitrificação , Microbiota , Antibacterianos/farmacologia , Reatores Biológicos , Nitritos , Nitrogênio , Águas Residuárias
19.
ACS Omega ; 5(10): 5534-5539, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32201846

RESUMO

Organometallic sandwich complexes, composed of cyclic hydrocarbon ligands and transition-metal atoms, display unique physical and chemical properties. In this work, the electronic and spin transport properties of one-dimensional (1D) VBz2 ligand bimetallic sandwich complexes, VBz2-TM (TM = Cr, Mn, and Fe), are systematically investigated using density functional theory and nonequilibrium Green's function method. The results show that all the 1D infinite molecular wires [(VBz2)TM]∞ (TM = Cr-Fe) are found to be thermodynamically stable with high binding energies (∼1.0-3.45 eV). In particular, they are predicted to be ferromagnetic half metals. Moreover, the I-V curves exhibit negative differential resistance for one, two, and three VBz2-TM wires at TM = Cr, Mn, and Fe, respectively, which is of great significance for certain electronic applications. Our findings strongly suggest that the benzene ligand bimetallic sandwich molecular wires are good candidates for potential electronics and spintronics.

20.
Ying Yong Sheng Tai Xue Bao ; 31(8): 2721-2730, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34494795

RESUMO

The objective evaluation of human settlement in cities helps find the problems exposed in urban development and make targeted adjustments to improve urban environment. Taking the downtown of Fuzhou as the research area, the residential area as the research unit, using multi-source data such as meteorological monitoring data, remote sensing imagery, map points of interest data (POI), and land planning data, we constructed monitoring system of urban human settlement from four aspects: environmental health and comfort, traffic convenience, city safety, and life conve-nience. The TOPSIS method was used to conduct a comprehensive evaluation of human settlement. The results showed that the human settlement level of downtown Fuzhou was quite different, which was high in the central area and low in the peripheral areas. The human settlement index was high in the middle of the urban area, low in the eastern and southern areas, with mixed high and low values in the western and northern areas. In each index layer, the characteristics of high-high agglomeration and low-low agglomeration of traffic convenience and life convenience were consistent with the distribution of high and low value clusters of the human settlement. Convenient transportation and complete service facilities had a greater impact on human settlement. The environmental health and comfort were characterized by interior low and edge high of the city, while city safety was characterized by interior high and edge low.


Assuntos
Monitoramento Ambiental , Meios de Transporte , Cidades , Humanos
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