62 research outputs found

    Character Formulas on Cohomology of Deformations of Hilbert Schemes of K3 Surfaces

    Full text link
    Let X be a hyperkahler manifold deformation equivalent to a Hilbert scheme of n points on a K3 surface. We compute the graded character formula of the generic Mumford-Tate group representation on the cohomology ring of X, and derive a generating series for deducing the number of canonical Hodge classes on X. The formula indicates the number of Hodge classes on X that remain Hodge under any deformation.Comment: To appear in J. London Math. So

    Modular Forms and Special Cubic Fourfolds

    Full text link
    We study the degree of the special cubic fourfolds in the Hilbert scheme of cubic fourfolds via a computation of the generating series of Heegner divisors of even lattice of signature (2, 20).Comment: 13 page

    Robust performance and stability of In2Оз thin-film transistors with atomic-layer-deposited channels

    Get PDF
    Atomic-layer-deposition (ALD) ln20 3 thinfilm transistors (TFTs) were fabricated under a maximum processing temperature of 200 °C. In order to reduce the concentration of oxygen vacancies in the ln20 3 channel, 0 2 plasma treatment was carried out on the TFTs by plasmaenhanced chemical vapor deposited (PECVD). The ln20 3 TFT treated at 200 °C for 240s exhibited good performance such as a field-effect mobility of 11 cm2/Vs, a threshold voltage (Vth) of 0.9 V, a subthreshold swing of 0.38 V/dec, and an on/off current ratio of 107 In addition, the device exhibits a small negative threshold voltage shift (A Vth) during negative gate bias stress. However, it showed a more pronounced A Vth under positive bias stress with a characteristic turnaround behavior from a positive A Vth to a negative A Vth. The positive AV m is attributed to the charge trapping effect, and the abnormal negative AVth should due to the hydrogen incorporated into the film

    Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province

    Get PDF
    Flowslide in loessic regions, characterized by their elongated shape and tendency to slide and accumulate along channels or gentle hillslopes, frequently lead to devastating and unpredictable disasters. The Yongguang 1# flowslide in Minxian County, Gansu Province, caused by the Minxian-Zhangxian Ms6.6 earthquake at 7:45AM on July 22, 2013, claimed twelve lives and had a volume of approximately 23×104 m3. The landslide had a vertical difference of 175m between its front and rear edges, a total length of 1 030 m, and a ratio of 0.17, classifying it as a long-runout landslide. This paper explored the characteristics of the sliding process and the sliding velocities of different portions of the flowslide through field survey and a comprehensive analysis of the observation data of the sliding process, while also analyzing the sliding mechanism. Triggered by earthquake, the runout process of the flowslide has been affected by local terrain. The flowslide experienced two complex sliding stages of acceleration and deceleration. Initially, the landslide slid as a whole in the front platform area for 50 to 130 m, and then the front sliding body with an volume of about 6×104 m3 continued to slide along the front channel for 740 m, resulting in a maximum runout distance of 870 m. The entire sliding process lasted about 7 hours, with a maximum sliding speed of approximately 10.6 m/s, and an average sliding speed of 0.034 m/s. The formation of the Yongguang 1# landslide was influenced by the coupled effects of seismic activity and early-precipitation. The earthquake, preceded by heavy rainfall, led to infiltration and softening of the soil. During the sliding process, the high water content in the sliding zone generated high pore water pressure, and in some cases, liquefaction occurred. The channel-shaped topography and low permeability of the sliding zone soil caused a very slow dissipation of pore water pressure, resulting in a significant reduction in frictional resistance in the sliding zone soil throughout the entire sliding process, with a noticeable velocity-sustaining effect. These factors are the primary reasons for the long-runout of the Yongguang 1# landslide

    Deformations of Hilbert Schemes of Points on K3 Surfaces and Representation Theory

    No full text
    We study the cohomology rings of Kaehler deformations X of Hilbert schemes of points on K3 surfaces by representation theory. We compute the graded character formula of the Mumford - Tate group representation on the cohomology ring of X. Furthermore, we also study the Hodge structure of X, and find the generating series for deducting the number of canaonical Hodge classes in the middle cohomology

    Ultrahigh Energy Storage Properties in (Sr0.7Bi0.2)TiO3-Bi(Mg0.5Zr0.5)O3 Lead-Free Ceramics and Potential for High-Temperature Capacitors

    Get PDF
    2020 by the authors. Due to the enhanced demand for numerous electrical energy storage applications, including applications at elevated temperatures, dielectric capacitors with optimized energy storage properties have attracted extensive attention. In this study, a series of lead-free strontium bismuth titanate based relaxor ferroelectric ceramics have been successfully synthesized by high temperature solid-state reaction. The ultrahigh recoverable energy storage density of 4.2 J/cm3 under 380 kV/cm, with the high efficiency of 88%, was obtained in the sample with x = 0.06. Of particular importance is that this ceramic composition exhibits excellent energy storage performance over a wide work temperature up to 150 °C, with strong fatigue endurance and fast discharge speed. All these merits demonstrate the studied ceramic system is a potential candidate for high-temperature capacitors as energy storage devices

    Weak Approximation for Cubic Hypersurfaces and Degree 4 del Pezzo Surfaces

    No full text
    International audienceIn this article we prove the following theorems about weak approximation of smooth cubic hypersurfaces and del Pezzo surfaces of degree 4 defined over global fields. (1) For cubic hypersurfaces of dimension at least two defined over global function fields, if there is a rational point, then weak approximation holds at places of good reduction whose residue field has at least eleven elements. (2) For del Pezzo surfaces of degree 4 defined over global function fields, if there is a rational point, then weak approximation holds at places of good reduction whose residue field has at least thirteen elements. (3) Weak approximation holds for cubic hypersurfaces of dimension at least ten defined over a global function field of characteristic not equal to 2,3,5 or a purely imaginary number field

    Design and Polarization Characteristics Analysis of Dihedral Based on Salisbury Screen

    No full text
    Salisbury screens have a number of unique electromagnetic scattering characteristics. When appropriately designed, the Salisbury screen can reach the radar target signature transform. Based on the electromagnetic scattering characteristics of the Salisbury screen, we designed a novel dihedral corner, and theoretically analyzed and simulated its electromagnetic scattering characteristics in this study. The results reveal the monostatic radar cross section curves of the 90°and 60° Salisbury screen dihedral and metal dihedral, respectively. Taking an orthogonal dihedral corner as an example, we obtained the polarization scattering matrixes for different incident degrees. In addition, we investigated the influence of illumination frequency, target gestures, and other key factors on the polarization characteristics of the Salisbury screen dihedral corner. The theoretical and simulation analysis results show that compared with the conventional metal dihedral corner, the Salisbury screen dihedral corner significantly influences the scattering characteristics and will have potential application in electronic warfare

    Review of the Application of Microwave Heating Technology in Asphalt Pavement Self-Healing and De-icing

    No full text
    In the past decades, a large amount of research was conducted to investigate the application prospect of microwave heating technology in improving the efficiency of asphalt pavement self-healing and de-icing. This paper reviewed the achievements in this area. Firstly, the properties of asphalt concrete after microwave heating were summarized, including microwave sensitivity and heating uniformity. Then, the evaluation indicators and influence factors of the self-healing properties of the asphalt mixtures heated by microwave were reviewed. Finally, the application of microwave heating in asphalt pavement de-icing was explored. In addition, asphalt pavement aging due to microwave heating was also reviewed. It was found that microwave heating technology has good prospects in promoting asphalt pavement self-healing and de-icing. There are also some problems that should be studied in depth, such as the cost-effectiveness of microwave-sensitive additives (MSAs), the performance of the pavement with MSAs, mechanism-based self-healing performance indicators, and the aging of asphalt pavements under cycling microwave heating
    corecore