Growth of Large Domain Epitaxial Graphene on the C-Face of SiC

Growth of epitaxial graphene on the C-face of SiC has been investigated. Using a confinement controlled sublimation (CCS) method, we have achieved well controlled growth and been able to observe propagation of uniform monolayer graphene. Surface patterns uncover two important aspects of the growth, i.e. carbon diffusion and stoichiometric requirement. Moreover, a new "stepdown" growth mode has been discovered. Via this mode, monolayer graphene domains can have an area of hundreds of square micrometers, while, most importantly, step bunching is avoided and the initial uniformly stepped SiC surface is preserved. The stepdown growth provides a possible route towards uniform epitaxial graphene in wafer size without compromising the initial flat surface morphology of SiC.Comment: 18 pages, 8 figure

Stimulation of vagus nerve for patients with disorders of consciousness: a systematic review

PurposeThe purpose of this study is to evaluate the efficacy and safety of stimulating the vagus nerve in patients with disorders of consciousness (DOCs).MethodsA comprehensive systematic review was conducted, encompassing the search of databases such as PubMed, CENTRAL, EMBASE and PEDro from their inception until July 2023. Additionally, manual searches and exploration of grey literature were performed. The literature review was conducted independently by two reviewers for search strategy, selection of studies, data extraction, and judgment of evidence quality according to the American Academy of Cerebral Palsy and Developmental Medicine (AACPDM) Study Quality Scale.ResultsA total of 1,269 articles were retrieved, and 10 studies met the inclusion criteria. Among these, there were three case reports, five case series, and only two randomized controlled trials (RCTs). Preliminary studies have suggested that stimulation of vagus nerve can enhance the levels of DOCs in both vegetative state/unresponsive wakefulness state (VS/UWS) and minimally conscious state (MCS). However, due to a lack of high-quality RCTs research and evidence-based medical evidence, no definitive conclusion can be drawn regarding the intervention’s effectiveness on consciousness level. Additionally, there were no significant adverse effects observed following stimulation of vagus nerve.ConclusionA definitive conclusion cannot be drawn from this systematic review as there was a limited number of eligible studies and low-quality evidence. The findings of this systematic review can serve as a roadmap for future research on the use of stimulation of vagus nerve to facilitate recovery from DOCs

Dressed ion acoustic solitary waves in quantum plasmas with two polarity ions and relativistic electron beams

A theory for dressed quantum ion acoustic waves (QIAWs), which includes higher-order corrections when QIAWs are investigated by the reductive perturbation method, is presented for unmagnetized plasmas containing positive and negative ions and weakly relativistic electron beams. The properties of the QIAWs are investigated using a quantum hydrodynamic model, from which a Korteweg–de Vries equation is derived using the reductive perturbation method. An equation including higher-order dispersion and nonlinearity corrections is also derived, and the physical parameter space is discussed for the importance of these correction

Numerical simulations of semi-armor-piercing warhead penetrating aircraft carrier target

FEM models of semi-armor-piercing warhead penetrating aircraft carrier deck are established, which are validated by related experimental data. Base on the models, the process of semi-armor-piercing warhead penetrating aircraft carrier deck with different incidence angles and attack angles are carried out. The results show that incidence angles have no remarkable influence on penetration capability of the projectile under the circumstance of zero attack angle. Ductility reaming damage mode and adiabatic plugging damage mode are exhibited in the penetration process. Attack angles have notable influence on penetration capability of the projectile. The FEM models and the results could provide reference for penetration effect research of semi-armor-piercing warhead penetrating aircraft carrier target

Mechanical Response of Square Honeycomb Sandwich Plate with Asymmetric Face Sheet Subjected to Blast Loading

AbstractSandwich structures are widely used in many important engineering to resist the blast loading. In order to improve the capacity of energy absorption, topology of core structure, .e.g. foam, folded plate, square and hexagonal honeycombs, and pyramidal truss is studied. However, very few investigations have been carried out to study the dynamic mechanical response and energy absorption of sandwich plate with asymmetric face sheet. In this paper, the dynamic mechanical response of sandwich plate with asymmetric face sheet is numerically analyzed using LS-DYNA code. For the sandwich plate with asymmetric face sheet, the thickness of core, the thickness of wall, the cell size and the mass of sandwich plate are fixed in analysis. We take the thickness ratio δ of the upper face sheet to the lower face sheet to be 2/5, 3/4, 1, 4/3 and 5/2, respectively. The maximum deflection and energy absorption of the sandwich plate subjected to blast loading are investigated for different δ. And the performance of the sandwich plate is compared to that of the solid plate with the same mass and the same material. The efficiency of energy absorption and the performance of resistance to blast are also obtained for the five structures under the same mass of TNT charge. The effect of δ on the dynamic response of square honeycomb is discussed. The results can be used for optimizing design of sandwich plate with enough resistance to blast

Numerical simulations of semi-armor-piercing warhead penetrating aircraft carrier target

FEM models of semi-armor-piercing warhead penetrating aircraft carrier deck are established, which are validated by related experimental data. Base on the models, the process of semi-armor-piercing warhead penetrating aircraft carrier deck with different incidence angles and attack angles are carried out. The results show that incidence angles have no remarkable influence on penetration capability of the projectile under the circumstance of zero attack angle. Ductility reaming damage mode and adiabatic plugging damage mode are exhibited in the penetration process. Attack angles have notable influence on penetration capability of the projectile. The FEM models and the results could provide reference for penetration effect research of semi-armor-piercing warhead penetrating aircraft carrier target

Long non-coding RNA TUG1 knockdown hinders the tumorigenesis of multiple myeloma by regulating the microRNA-34a-5p/NOTCH1 signaling pathway

Multiple myeloma (MM) is a serious health issue in hematological malignancies. Long non-coding RNA taurine-upregulated gene 1 (TUG1) has been reported to be highly expressed in the plasma of MM patients. However, the functions of TUG1 in MM tumorigenesis along with related molecular basis are still undefined. In this study, increased TUG1 and decreased microRNA-34a-5p (miR-34a-5p) levels in MM tissues and cells were measured by the real-time quantitative polymerase reaction assay. The expression of relative proteins was determined by the Western blot assay. TUG1 knockdown suppressed cell viability, induced cell cycle arrest and cell apoptosis in MM cells, as shown by Cell Counting Kit-8 and flow cytometry assays. Bioinformatics analysis, luciferase reporter assay, and RNA pull-down assay indicated that miR-34a-5p was a target of TUG1 and directly bound to notch receptor 1 (NOTCH1), and TUG1 regulated the NOTCH1 expression by targeting miR-34a-5p. The functions of miR-34a-5p were abrogated by TUG1 upregulation. Moreover, TUG1 loss impeded MM xenograft tumor growth in vivo by upregulating miR-34a-5p and downregulating NOTCH1. Furthermore, TUG1 depletion inhibited the expression of Hes-1, Survivin, and Bcl-2 protein in MM cells and xenograft tumors. TUG1 knockdown inhibited MM tumorigenesis by regulating the miR-34a-5p/NOTCH1 signaling pathway in vitro and in vivo, deepening our understanding of the TUG1 function in MM

A Robust Automatic Method to Extract Building Facade Maps from 3D Point Cloud Data

Extracting facade maps from 3D point clouds is a fast and economical way to describe a building’s surface structure. Existing methods lack efficiency, robustness, and accuracy, and depend on many additional features such as point cloud reflectivity and color. This paper proposes a robust and automatic method to extract building facade maps. First, an improved 3D Hough transform is proposed by adding shift vote and 3D convolution of the accumulator to improve computational efficiency and reduce peak fuzziness and dependence on the step selection. These modifications make the extraction of potential planes fast and accurate. Second, the coplane and vertical plane constraints are introduced to eliminate pseudoplanes and nonbuilding facades. Then, we propose a strategy to refine the potential facade and to achieve the accurate calibration and division of the adjacent facade boundaries by clustering the refined point clouds of the facade. This process solves the problem where adjoining surfaces are merged into the same surface in the traditional method. Finally, the extracted facade point clouds are converted into feature images. Doors, windows, and building edges are accurately extracted via deep learning and digital image processing techniques, which combine to achieve accurate extraction of building facades. The proposed method was tested on the MLS and TLS point cloud datasets, which were collected from different cities with different building styles. Experimental results confirm that the proposed method decreases computational burden, improves efficiency, and achieves the accurate differentiation of adjacent facade boundaries with higher accuracy compared with the traditional method, verifying the robustness of the method. Additionally, the proposed method uses only point cloud geometry information, effectively reducing data requirements and acquisition costs