Phase diagram of superconducting vortex ratchet motion in a superlattice with noncentrosymmetry

Ratchet motion of superconducting vortices, which is a directional flow of vortices in superconductors, is highly useful for exploring quantum phenomena and developing superconducting devices, such as superconducting diode and microwave antenna. However, because of the challenges in the quantitative characterization of the dynamic motion of vortices, a phase diagram of the vortex ratchet motion is still missing, especially in the superconductors with low dimensional structures. Here we establish a quantitative phase diagram of the vortex ratchet motion in a highly anisotropic superlattice superconductor, (SnS)1.17NbS2, using nonreciprocal magnetotransport. The (SnS)1.17NbS2, which possesses a layered atomic structure and noncentrosymmetry, exhibits nonreciprocal magnetotransport in a magnetic field perpendicular and parallel to the plane, which is considered a manifest of ratchet motion of superconducting vortices. We demonstrated that the ratchet motion is responsive to current excitation, magnetic field and thermal perturbation. Furthermore, we extrapolated a giant nonreciprocal coefficient ({\gamma}), which quantitatively describes the magnitude of the vortex ratchet motion, and eventually established phase diagrams of the ratchet motion of the vortices with a quantitative description. Last, we propose that the ratchet motion originates from the coexistence of pancake vortices (PVs) and Josephson vortices (JVs). The phase diagrams are desirable for controlling the vortex motion in superlattice superconductors and developing next-generation energy-efficient superconducting devices

Taxonomy of the genus Epsilon from China, with a new species and an updated key to the Oriental species (Hymenoptera, Vespidae, Eumeninae)

A new species of potter wasps, Epsilon similimanasicum sp. nov. is described and illustrated from Zhejiang, China. The holotype specimen of Epsilon subfistulosum (Wickwar, 1908) was examined and based on the characters of the type specimen, it is transferred from the genus Epsilon de Saussure to the genus Pararrhynchium de Saussure, as Pararrhynchium subfistulosum comb. nov. In addition, an updated key to the Oriental species of Epsilon is provided

Taxonomy of the genus Epsilon from China, with a new species and an updated key to the Oriental species (Hymenoptera, Vespidae, Eumeninae)

A new species of potter wasps, Epsilon similimanasicum sp. nov. is described and illustrated from Zhejiang, China. The holotype specimen of Epsilon subfistulosum (Wickwar, 1908) was examined and based on the characters of the type specimen, it is transferred from the genus Epsilon de Saussure to the genus Pararrhynchium de Saussure, as Pararrhynchium subfistulosum comb. nov. In addition, an updated key to the Oriental species of Epsilon is provided

Multiband Radar Signal Coherent Processing Algorithm for Motion Target

In real application, most aerial targets are movable. In this paper, an effective multiple subbands coherent processing method is proposed for moving target. Firstly, an echoed signal model of motion target based on geometrical theory of diffraction is established and the influence of velocity on range profile of the target is analyzed. Secondly, a method based on minimum entropy principle is used to compensate velocity. Then, incoherent factors including a quadratic phase term, a linear phase factor, a fixed factor, and an amplitude difference term are analyzed. Subsequently, efficient methods are applied to estimate other incoherent factors, except that the quadratic term is small enough to be ignored. Finally, the feasibility and performance of the proposed method are investigated through numerical simulation

Taxonomy of the genus Epsilon from China, with a new species and an updated key to the Oriental species (Hymenoptera, Vespidae, Eumeninae)

A new species of potter wasps, Epsilon similimanasicum sp. nov. is described and illustrated from Zhejiang, China. The holotype specimen of Epsilon subfistulosum (Wickwar, 1908) was examined and based on the characters of the type specimen, it is transferred from the genus Epsilon de Saussure to the genus Pararrhynchium de Saussure, as Pararrhynchium subfistulosum comb. nov. In addition, an updated key to the Oriental species of Epsilon is provided

Changes in ecosystem services and their tradeoffs and synergies in the Yangtze River Basin from 2000 to 2020

[Objective] The Yangtze River is an important ecological security barrier in China. Analyzing the spatial-temporal changes of ecosystem services and the driving force of land use change in the Yangtze River Basin is conducive to the coordinated development of ecology and economy in the region. [Methods] Based on remote sensing data from 2000 to 2020, the RUSLE model and the InVEST model were used to calculate the amount of soil retention, water yield, and carbon sequestration in the Yangtze River Basin. The Sen trend method and hotspot analysis method were used to analyze changes in ecosystem services. Partial correlation analysis was used to analyze the tradeoff-synergy relationships between services, and the reasons for change in ecosystem services were analyzed from the perspective of land use change. [Results] (1) From 2000 to 2020, the trends of change of average annual soil retention, water yield, and carbon sequestration in the basin were about 1.75 t/(hm2·a), -1.33×103 m3/(km2·a), and 1.62 gC/(m2·a). Except for water yield, which showed a decreasing trend in some areas, other services showed an increasing trend in most areas. The overall area of ecosystem services hotspots was expanded, especially those dominated by carbon sequestration and water yield services. (2) Soil retention and water yield were mainly in an insignificant tradeoff relationship, soil retention and carbon sequestration were mainly in a significant synergistic relationship, and carbon sequestration and water yield were mainly in an insignificant synergistic relationship. (3) The conversion from cropland to forestland had a greater impact on soil conservation services, the conversion from cropland to grassland had a greater impact on carbon sequestration services, and the conversion from grassland to cropland had a greater impact on water yield services. (4) Soil retention, water yield, and carbon sequestration services tended to be synergistic when cropland was converted to forest and grass areas, and tended to be tradeoff when the forest and grass areas were turned to cropland. [Conclusion] The ecosystem services in the Yangtze River Basin have improved in general. The increase in forest and grass area in land use change had a positive effect on the improvement of ecosystem services and the coordinated development between services. The game between land development and ecological protection has led to dynamic changes in ecosystem services. Considering the importance of regional economic development, it is necessary to balance development and protection, and achieve green and sustainable development

Additions to the knowledge of the genus Allorhynchium van der Vecht, 1963 from China (Hymenoptera, Vespidae, Eumeninae)

In this study, Halysituberosus Dong & Wang, 2017 is treated as a synonym of Allorhynchium van der Vecht, 1963 (syn. nov.). Halysituberosus yingjiangensis Dong & Wang, 2017 is a new synonym of Allorhynchium lugubrinum (Cameron, 1900) (syn. nov.) and Halysituberosus menglianensis Dong & Wang, 2017 is transferred to Allorhynchium as a new combination (comb. nov.). Based on additional COI gene sequencing and morphological characters including genitalia characters, both Allorhynchium diffinis (Giordani Soika, 1986) and Allorhynchium radiatum Li, Barthélémy & Carpenter, 2019 are confirmed to be valid species, and their males of the two species are described for the first time. Allorhynchium quadrimaculatum Gusenleitner, 1997 is newly recorded from China. A key to the Chinese species of Allorhynchium are also updated

The complete mitochondrial genome of Orancistrocerus aterrimus aterrimus and comparative analysis in the family Vespidae (Hymenoptera, Vespidae, Eumeninae)

To date, only one mitochondrial genome (mitogenome) in the Eumeninae has been reported in the world and this is the first report in China. The mitogenome of O. a. aterrimus is 17 972 bp long, and contains 38 genes, including 13 protein coding genes (PCGs), 23 tRNA genes, two rRNA genes, a long non-coding region (NCR), and a control region (CR). The mitogenome has 79.43% A + T content, its 13 PCGs use ATN as the initiation codon except for cox1 using TTG, and nine genes used complete translation termination TAA and four genes have incomplete stop codon T (cox2, cox3, nad4, and cytb). Twenty-two of 23 tRNAs can form the typical cloverleaf secondary structure except for trnS1. The CR is 1 078 bp long with 84.69% A+T content, comprising 28 bp tandem repeat sequences and 13 bp T-strech. There are two gene rearrangements which are an extra trnM2 located between trnQ and nad2 and the trnL2 in the upstream of nad1. Within all rearrangements of these mitogenomes reported in the family Vespidae, the translocation between trnS1 and trnE genes only appears in Vespinae, and the translocation of trnY in Polistinae and Vespinae. The absent codons of 13 PCGs in Polistinae are more than those both in Vespinae and Eumeninae in the family Vespidae. The study reports the complete mitogenome of O. a. aterrimus, compares the characteristics and construct phylogenetic relationships of the mitogenomes in the family Vespidae

NiO removal of Ni/Au Ohmic contact to p-GaN after annealing

The Ni/Au contact was treated with oxalic acid after annealing in O_2 ambient, and its I-V characteristic showed the property of contact has been obviously improved. An Auger electron spectroscopy (AES) depth pro-file of the contact as-annealed showed that the top layer was highly resistive NiO, while an X-ray photo-electron spectroscopy (XPS) of oxalic acid treated samples indicated that the NiO has been removed effectively. A scanning electron microscope (SEM) was used to observe the surface morphology of the contacts, and it was found that the lacunaris surface right after annealing became quite smooth with lots of small Au exposed areas after oxalic acid treatment. When the test probe or the subsequently deposited Ti/Au was directly in contact with these small Au areas, they worked as low resistive current paths and thus decrease the specific contact resistance