Hasil untuk "Property"

D. Abergel, V. Apalkov, J. Berashevich et al.

The electronic properties of graphene, a two-dimensional crystal of carbon atoms, are exceptionally novel. For instance, the low-energy quasiparticles in graphene behave as massless chiral Dirac fermions which has led to the experimental observation of many interesting effects similar to those predicted in the relativistic regime. Graphene also has immense potential to be a key ingredient of new devices, such as single molecule gas sensors, ballistic transistors and spintronic devices. Bilayer graphene, which consists of two stacked monolayers and where the quasiparticles are massive chiral fermions, has a quadratic low-energy band structure which generates very different scattering properties from those of the monolayer. It also presents the unique property that a tunable band gap can be opened and controlled easily by a top gate. These properties have made bilayer graphene a subject of intense interest. In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. Recent experminental observations of a metal–insulator transition in hydrogenated graphene is discussed in terms of a self-consistent theory and compared with related numerical simulations. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect and optical properties. Confinement of electrons in graphene is non-trivial due to Klein tunnelling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane–gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.

N. Mermin

B. Alpern, F. Schneider

B. Hjorth

T. Daubert, R. Danner

P. Meredith, T. Sarna

R. Munro

The physical, mechanical, and thermal properties of polycrystalline TiB2 are examined with an emphasis on the significant dependence of the properties on the density and grain size of the material specimens. Using trend analysis, property relations, and interpolation methods, a coherent set of trend values for the properties of polycrystalline TiB2 is determined for a mass fraction of TiB2 ⩾ 98 %, a density of (4.5±0.1) g/cm3, and a mean grain size of (9±1) µm.

Z. Fan, J. Lu

O. Kupferman, M. Vardi

Y. Ai, J. Jane

Babu S., Rama Narayanan V.

Financial fraudsters use Gen AI, digital channels, global networks, and synthetic identities making it complex to identify the fraudulent activities. Traditional rule-based systems relying on traditional methods do not identify frauds which use multi-step transaction routing with multiple institutions and across borders. Graph database using Labelled Property Graphs, represents customers, accounts, and transactions as interconnected nodes and edges. By ingesting live transaction data, they apply pattern-matching and community-detection to expose suspicious subgraphs. Money-laundering rings or collusive clusters—and let investigators trace multi-hop links to “hub” accounts with clear visual audit trails. Machine learning models trained on vast historical datasets, using supervised classifiers (e.g., gradient boosting) and unsupervised anomaly detectors. Features like transaction amounts, geolocation consistency, device fingerprints, and temporal sequences feed these models, while recurrent architectures capture evolving fraud tactics. Yet they often suffer from concept drift, require extensive labelled data, underperform on imbalanced cases, and behave as opaque black boxes, generating false positives and hampering trust. A hybrid framework combines relational graph insights with statistical scoring, boosting detection accuracy, reducing false alarms, and enhancing investigators’ confidence in fraud detection and prevention.

Indira Chatterji, Martin Kassabov

We construct a finitely presented group with property (T) which can not act on on reasonable spaces. Such group is constructed using an generalization of Hall embedding theorem, where property (T) is added at the expense of weakening the simplicity requirement.

Lei Han, Jingying Tan, Yucui Zhang

Abstract Given the promising prospect of nanozymes in colorimetric test strips, it is essential to eliminate the interferences of their multi-activities and various colors on the test strip. Here, white Mn-based metal-organic frameworks (Mn-MOFs) with ultrathin 2D morphology (3 nm thick) were successfully synthesized by a simple ultrasonic approach. The origin of the white optical property in Mn-MOFs was systematically investigated, revealing that it stems from specific metal-ligand coordination polymerization rather than morphological features or defect states. Mn-MOF nanozymes possessed exclusive peroxidase-mimicking activity rather than oxidase-like activity, effectively resisting O2 interference during colorimetric assay. Moreover, Mn-MOF nanozymes displayed unique substrate selectivity without additional modification. Unlike other colored nanozymes, the whiteness of Mn-MOF nanozymes enhanced the paper’s whiteness, boosting contrast for colorimetric detection on test strip. This study pioneers a systematic investigation into the origin of whiteness in MOF nanozymes. The coordination-defined properties enable interference-free optical design and O2-resistant on-site detection.

Alexander V. Osipov

We give a characterization of the $Δ_1$-property of any Tychonoff space $X$ in terms of the function space $B_1(X)$ of all Baire-one real-valued functions on a space $X$ with the topology of pointwise convergence. We establish that for a Tychonoff space $X$ the $Δ_1$-property is equivalent to the Choquet property of $B_1(X)$. Also we construct under $ZFC$ an example of a separable pseudocompact space $X$ such that $C_p(X)$ is $κ$-Frechet-Urysohn but $X$ fails to be a $Δ_1$-space. This answers a question of Kakol-Leiderman-Tkachuk.

Abdulrahman Al-Fakih, Ardiansyah Koeshidayatullah, Nabil A. Saraih et al.

Accurate geological modeling is critical for reservoir characterization, yet traditional methods struggle with complex subsurface heterogeneity, and they have problems with conditioning to observed data. This study introduces Pix2Geomodel, a novel conditional generative adversarial network (cGAN) framework based on Pix2Pix, designed to predict reservoir properties (facies, porosity, permeability, and water saturation) from the Rotliegend reservoir of the Groningen gas field. Utilizing a 7.6 million-cell dataset from the Nederlandse Aardolie Maatschappij, accessed via EPOS-NL, the methodology included data preprocessing, augmentation to generate 2,350 images per property, and training with a U-Net generator and PatchGAN discriminator over 19,000 steps. Evaluation metrics include pixel accuracy (PA), mean intersection over union (mIoU), frequency weighted intersection over union (FWIoU), and visualizations assessed performance in masked property prediction and property-to-property translation tasks. Results demonstrated high accuracy for facies (PA 0.88, FWIoU 0.85) and water saturation (PA 0.96, FWIoU 0.95), with moderate success for porosity (PA 0.70, FWIoU 0.55) and permeability (PA 0.74, FWIoU 0.60), and robust translation performance (e.g., facies-to-facies PA 0.98, FWIoU 0.97). The framework captured spatial variability and geological realism, as validated by variogram analysis, and calculated the training loss curves for the generator and discriminator for each property. Compared to traditional methods, Pix2Geomodel offers enhanced fidelity in direct property mapping. Limitations include challenges with microstructural variability and 2D constraints, suggesting future integration of multi-modal data and 3D modeling (Pix2Geomodel v2.0). This study advances the application of generative AI in geoscience, supporting improved reservoir management and open science initiatives.

Rainis Haller, Jaan Kristjan Kaasik, Andre Ostrak

We separate the local diameter two property from the diameter two property and their weak-star counterparts from each other in spaces of Lipschitz functions. We characterise the $w^*$-LD$2$P, the $w^*$-D$2$P, the LD$2$P, and the SD$2$P in these spaces. We introduce a generalised version of cyclical monotonicity to study functionals on spaces of Lipschitz functions.

Rudra Awdhesh Kumar Mishra, Gothandam Kodiveri Muthukaliannan

Abstract Antimicrobial peptides have garnered increasing attention as potential alternatives due to their broad-spectrum antimicrobial activity and low propensity for developing resistance. This is for the first time; proteome sequences of Aegle marmelos were subjected to in-silico digestion and AMP prediction were performed using DBAASP server. After screening the peptides on the basis of different physiochemical property, peptide sequence GKEAATKAIKEWGQPKSKITH (AM1) shows the maximum binding affinity with − 10.2 Kcal/mol in comparison with the standard drug (Trimethoprim) with − 7.4 kcal/mol and − 6.8 Kcal/mol for DHFR and SaTrmK enzyme respectively. Molecular dynamics simulation performed for 300ns, it has been found that peptide was able to stabilize the protein more effectively, analysed by RMSD, RMSF, and other statistical analysis. Free binding energy for DHFR and SaTrmK interaction from MMPBSA analysis with peptide was found to be -47.69 and − 44.32 Kcal/mol and for Trimethoprim to be -13.85 Kcal/mol and − 11.67 Kcal/mol respectively. Further in-vitro study was performed against Methicillin Susceptible Staphylococcus aureus (MSSA), Methicillin Resistant Staphylococcus aureus (MRSA), Multi-Drug Resistant Staphylococcus aureus (MDR-SA) strain, where MIC values found to be 2, 4, and 8.5 µg/ml lesser in comparison to trimethoprim which has higher MIC values 2.5, 5, and 9.5 µg/ml respectively. Thus, our study provides the insight for the further in-vivo study of the peptides against multi-drug resistant S. aureus.

Felix Wetzler, Jan-Erik Nebel, Wei Zhang et al.

When fabricating magnetic components for micro-electro-mechanical systems, the intrinsic material properties as well as the magnetic anisotropy of the deposited material and the fabricated devices must be adjusted to the application. This work focuses on electrochemically deposited cobalt phosphorus layers from a sulfate-based electrolyte to be used as hard magnetic scales in position measurement systems. In preliminary tests round discs (5 mm diameter, 20 or 10 μm height) were fabricated, showing the influence of three process parameters (current density, pH-value and temperature) on the chemical composition and the magnetic behavior of the deposited cobalt phosphorus. Hereby deposition parameters to produce hard magnetic cobalt phosphorus are defined. Deposits with up to 6 wt.-% phosphorus show hard magnetic behavior, whereas deposits with more than 6 wt.-% show soft magnetic behavior. This is correlated with a transition from crystalline to amorphous structures. In further investigations arrays of micro scales (40 μm width, 10 μm height) were fabricated to show the influence of direct current and pulsed current on the properties of the deposits. Pulsed current increases coercive field strength by about 40 %, resulting in maximum values of 23 kA/m (in-plane) and 14 kA/m (out-of-plane). Remanence increases by about 30 %, resulting in maximum values of 0.40 T (in-plane) and 0.2 T (out-of-plane). Pulse plating changes preferred orientation from (110) to (100) and slightly increases grain size by about 20 %, resulting in an average grain size of 25 nm.

Zhe Zhao, Leonardo Modesto

Abstract In a large class of nonlocal as well as local higher derivative theories minimally coupled to the matter sector, we investigate the exactness of two different classes of homogeneous Gödel-type solutions, which may or may not allow closed time-like curves (CTC). Our analysis is limited to spacetimes solving the Einstein’s EoM, thus we can not exclude the presence of other Gödel-type solutions solving the EoM of local and nonlocal higher derivative theories but not the Einstein’s EoM. It turns out that the homogeneous Gödel spacetimes without CTC are basically exact solutions for all theories, while the metrics with CTC are not exact solutions of (super-)renormalizable local or nonlocal gravitational theories. Hence, the quantum renormalizability property excludes theories suffering of the Gödel’s causality violation. We also comment about nonlocal gravity non-minimally coupled to matter. In this class of theories, all the Gödel’s spacetimes, with or without CTC, are exact solutions at classical level. However, the quantum corrections, although perturbative, very likely spoil the exactness of such solutions. Therefore, we can state that the Gödel’s Universes with CTC and the super-renormalizability are mutually exclusive.

Walaa S. Anwar, Fatma M. Abdel-maksoud, Ahmed M. Sayed et al.

Abstract Background Calamus rotang L. (CR) is an Indian shrub. The leaves and other organs of the plant are traditionally used in India for treatment of various diseases. The in vitro antioxidant property of the leaves extract was previously established. Thus, the current study aimed to evaluate the antioxidant and hepatoprotective effects of CR ethyl acetate extract at a dose of 350 mg/kg on CCl4 induced hepatotoxic rats through different mechanisms. Methods Histopathological examination of the treated rats’ group in comparison with positive and negative controls were performed. Quantitative measuring of the proinflammatory cytokines (TNF α), inflammatory regulators (Arginase, PPAR α) and the antiapoptotic protein Bcl-2 in comparison with positive and negative control groups was achieved using immunohistochemical examination. HPLC profiling of the polyphenol contents and molecular docking of the identified compounds against BH3 proapoptotic protein were correspondingly studied to evaluate the potential antiapoptotic property. Results The CR extract greatly protects the liver tissue through the suppression of TNF α, arginase and PPAR α induced by CCl4 as well as its enhancement of the antiapoptotic Bcl-2 protein. Fourteen polyphenols of different classes were identified in CR extract and tested via molecular docking for their potential antiapoptotic activities against BH3 protein. Naringin, rutin, 7-hydroxy flavone, and ellagic acid compounds exhibit the highest affinity and potential inhibition of pro-apoptotic protein BH3 via molecular docking study. Conclusions The ethyl acetate fraction of the leaves of C. rotang is rich in polyphenols that exhibited potent hepatoprotective effect on CCl4 induced hepatotoxic rats through its antioxidant, anti-inflammatory, anti-steatosis and antiapoptotic properties.