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This work proposes an innovative approach for supersonic flow field modeling around airfoils based on sparse convolutional neural networks (SCNN) and Bézier generative adversarial network (GAN), where 1) the SCNN model is built to end-to-end predict supersonic compressible physical flow fields around airfoils from spatially-sparse geometries and 2) the trained Bézier-GAN is utilized to generate plenty of smooth airfoils as well as the latent codes representing airfoils. The spatially-sparse positions of airfoil geometry are represented using Signed Distance Function (SDF). Particularly, the latent codes are merged with the SDF matrix and the Mach number to form the input of the SCNN model, effectively making the SCNN model possess more robust geometric adaptability to different flow conditions. The most significant contribution compared to the regular convolutional neural network is that SCNN introduces sparse convolutional operations to process spatially-sparse input matrix, specifically, which only focuses on the local area with flow information when performing convolution, eventually saving memory usage and improving the network’s attention on the flow area. Further, the testing results show that the SCNN model can more accurately predict supersonic flow fields with a mean absolute error lower than 5% and save 40% of GPU (Graphics Processing Unit) memory. These results indicate that the proposed SCNN model can capture the shock wave features of supersonic flow fields and improve learning efficiency and computing efficiency.

Emergent symmetry in Dirac system means that the system acquires an enlargement of two basic symmetries at some special critical point. The continuous quantum criticality between the two symmetry broken phases can be described within the framework of Gross-Neveu-Yukawa (GNY) model. Using the first-order $\epsilon$ expansion in $4-\epsilon$ dimensions, we study the critical structure and emergent symmetry of the chiral GNY model with $N_f$ flavors of four-component Dirac fermions coupled strongly to an $O(N)$ scalar field under a small $O(N)$-symmetry breaking perturbation. After determining the stable fixed point, we calculate the inverse correlation length exponent and the anomalous dimensions (bosonic and fermionic) for general $N$ and $N_f$. Further, we discuss the emergent-symmetry and the emergent supersymmetric critical point for $N\geq4$ on the basis of $O(N)$-GNY model. It turns out that the chiral emergent-$O(N)$ universality class is physically meaningful if and only if $N, Comment: 14pages,6figures,1table

Large components outside satellite body are extremely sensitive to the sound field. As the entire satellite acoustic-vibration (hereinafter referred to as acoustic) model is very complex, computationally intensive and time-consuming, the feasibility of only modelling these large components when they are just concerned deserves to be investigated. In this paper, an entire satellite model, a finite element (FE) model a statistical energy analysis (SEA) model of the solar array were firstly established, and then their results and time needed were compared in order to explore the fastest and most efficient modelling method of large components outside satellite body. The results demonstrate that modelling only solar array not the entire satellite is feasible when only it is concerned. The FE model of solar array should be used if the responses at each point are necessary, while the SEA model is recommended if not.

In order to solve the problems of high error rate and long time in the traditional signal error compensation method, a new nonlinear compensation method for the signal error of capacitance micro displacement sensor is designed. The structure of the capacitive micro displacement sensor is optimized. The signal acquisition module is used to collect the optimized capacitive micro displacement sensor signal, and the collected signal is processed by adding window interpolation FFT. According to the signal processing results, the RBF neural network model is used to realize the nonlinear compensation of the signal error of the capacitive micro displacement sensor. The experimental results show that the method has the advantages of less noise, lower compensation error rate and time consuming, and better practical application effect.

Graphene has much higher mechanical strength than other materials, but can be significantly influenced by the vacancy defect or Stone-Wales defect in the lattices. In this paper, we use molecular dynamics simulation to study the effects of vacancy and Stone-Wales defects in fracture behavior of the defective graphene. The results show that the fracture strength of graphene is more sensitive to the vacancy defects than that of Stone-Wales defect. When the defect is located in the center of graphene, the fracture strength of defect graphene is less than that of defect-free graphene. When the defect is far away from the center of graphene, the fracture strength of defect graphene will be enhanced, even greater than that of defect-free graphene. This study may help to understand the properties of graphene with defect, but also show the potential for graphene-based materials in engineering.

Acoustic-vibration prediction at early stage of satellite development can contribute to their structural and layout design. In this paper, numerical models of a practical satellite subjected to acoustic excitation at launch stage were established. Then, the effect of acoustic condition was further analyzed. The results demonstrate that it is difficult to predict all-frequency-band acoustic response of complex satellites by an individual method, so a combined method was proposed in this paper. The damping loss factor model of panels with equipment was introduced to resolve the issue of on-board equipment modelling in the statistical energy analysis model. The service modules are extremely sensitive to acoustic excitation of about 354∼2828Hz, which should be highlighted when carrying a rocket with a high sound pressure level at this frequency band.

In this study, BPA was selected as the research object to explore the effect of BPA on the development of reproductive system and its damage mechanism in the weaning F1 male offspring SD rats. The development of sexual organs and the change of sex hormone level in F1 male offspring were observed from the day of pregnancy when BPA of 50mg / kg, 100mg / kg and 200mg / kg was administered to the mother rats to the weaning period. The results showed that the serum PRL level of F0 parent rats in BPA group increased significantly at the end of weaning period, and the serum E2 level of 100 mg / kg and 200 mg / kg groups increased significantly. In F1 offspring, the dose of BPA was positively correlated with the level of serum E2, negatively correlated with the level of serum T, FSH decreased in 200mg / kg BPA group, and the organ coefficient of testis decreased significantly in 100mg / kg and 200mg / kg groups compared with the control group.

To explore the significance of p16 gene methylation and abnormal expression in cervical cancer, Methylation specific PCR (MSP) was used to detect 5 ′ CpG island methylation of p16 gene promoter in 60 cervical cancer tissues of different pathological types and clinical stages, who was chosen in Human province. Detection of homozygous deletion of exon 1 (E1) and exon 2 (E2) of p16 gene by PCR. Immunohistochemical analysis of p16 protein expression. The results showed that there was no methylation of p16 gene in normal control tissues and paracancerous tissues and no E1 and E2 deletions and abnormal p16 protein expression were found. The methylation rate of 60 cervical cancer samples was 21.67% (13 / 60), the deletion rate of p16 gene was 15.00% (9 / 60), and the expression rate of p16 protein was 51.67% (31 / 60). It can be seen that the positive expression rate of p16 gene protein decreased with the increase of clinical stage. The results suggest that p16 gene inactivation is common in cervical cancer and closely related to the pathological grade. p16 gene methylation plays a role in the development of cervical cancer.

In sharp contrast to conventional topological superfluids, higher order (order r > 1) topological superfluids in n dimensions do not host n - 1 dimensional Majorana boundary states, instead host n - r dimensional Majorana excitations. In this paper, we propose Majorana corner modes can emerge in a second order superfluid with s-wave pairing, instead of unconventional pairings such as d-wave and [Formula: see text]-wave pairings in most of previous proposals. There are three key ingredients in this scheme consisting of a topological insulator, an in-plane Zeeman field, and an s-wave pairing. Based on the low energy theory for edge states, where the effective Dirac mass sign changes at the corner, we unveil the emergence of Majorana corner modes. Our proposal provides a promising platform for implementing 2D second order topological superfluids and Majorana corner modes.

We present a quantum secure imaging (QSI) scheme based on the phase encoding and weak+vacuum decoy-state BB84 protocol of quantum key distribution (QKD). It allows us to implement a computational ghost imaging (CGI) system with more simplified equipment and reconstructed algorithm by using a digital micro-mirror device (DMD) to preset the specific spatial distribution of the light intensity. What is more, the quantum bit error rate (QBER) and the secure key rate analytical functions of QKD are used to see through the intercept-resend jamming attacks and ensure the authenticity of the imaging information. In the experiment, we obtained the image of the object quickly and efficiently by measuring the signal photon counts with a single-photon detector (SPD), and achieved a secure key rate of 571.0 bps and a secure QBER of 3.99%, which is well below the lower bound of QBER of 14.51%. Besides, our imaging system uses a laser with invisible wavelength of 1550 nm, whose intensity is as low as single-photon, that can realize weak-light imaging and is immune to the stray light or air turbulence, thus it will become a better choice for quantum security radar against intercept-resend jamming attacks.

In this paper, water-soluble nitrogen doped fluorescent carbon dots (N-CDs) have been prepared by a facile hydrothermal treatment of bagasse waste and urea. The prepared N-CDs were characterized by high resolution TEM, fluorescence spectroscopy, FTIR and x-ray photoelectron spectroscopy. The results revealed that the prepared N-CDs were mainly composed of hydroxyl, carboxyl and amino groups with an average size of ca. 5.0 nm. The prepared N-CDs exhibited excellent photoluminescence and emitted light blue fluorescence under a 365 nm UV light. Owing to the selective fluorescent quenching response of Hg2+, the prepared N-CDs have been used as a fluorescent probe for sensitive detection of Hg2+ in water. The fluorescent quenching mechanism could be due to the special coordination interaction between Hg2+ and the surface functional groups of the fluorescent N-CDs. Meanwhile, the fluorescence quenching efficiency decreased linearly with Hg2+ in the concentration range of 0.005–0.8 μM. The detection limit is low to 0.002 μM. The synthesized N-CDs were further applied to the detection of Hg2+ in real water samples.

The character of forming long-range contacts affects the three-dimensional structure of globular proteins deeply. As the different ability to form long-range contacts between 20 types of amino acids and 4 categories of globular proteins, the statistical properties are thoroughly discussed in this paper. Two parameters NC and ND are defined to confine the valid residues in detail. The relationship between hydrophobicity scales and valid residue percentage of each amino acid is given in the present work and the linear functions are shown in our statistical results. It is concluded that the hydrophobicity scale defined by chemical derivatives of the amino acids and nonpolar phase of large unilamellar vesicle membranes is the most effective technique to characterise the hydrophobic behavior of amino acid residues. Meanwhile, residue percentage Pi and sequential residue length Li of a certain protein i are calculated under different conditions. The statistical results show that the average value of Pi as well as Li of all-? proteins has a minimum among these 4 classes of globular proteins, indicating that all-? proteins are hardly capable of forming long-range contacts one by one along their linear amino acid sequences. All-? proteins have a higher tendency to construct long-range contacts along their primary sequences related to the secondary configurations, i.e. parallel and anti-parallel configurations of ? sheets. The investigation of the interior properties of globular proteins give us the connection between the three-dimensional structure and its primary sequence data or secondary configurations, and help us to understand the structure of protein and its folding process well.

Converting ultrasonic signal to ultrasonic pulse stream is the key step of finite rate of innovation (FRI) sparse sampling. At present, ultrasonic pulse-stream-forming techniques are mainly based on digital algorithms. No hardware circuit that can achieve it has been reported. This paper proposes a new quadrature demodulation (QD) based circuit implementation method for forming an ultrasonic pulse stream. Elaborating on FRI sparse sampling theory, the process of ultrasonic signal is explained, followed by a discussion and analysis of ultrasonic pulse-stream-forming methods. In contrast to ultrasonic signal envelope extracting techniques, a quadrature demodulation method (QDM) is proposed. Simulation experiments were performed to determine its performance at various signal-to-noise ratios (SNRs). The circuit was then designed, with mixing module, oscillator, low pass filter (LPF), and root of square sum module. Finally, application experiments were carried out on pipeline sample ultrasonic flaw testing. The experimental results indicate that the QDM can accurately convert ultrasonic signal to ultrasonic pulse stream, and reverse the original signal information, such as pulse width, amplitude, and time of arrival. This technique lays the foundation for ultrasonic signal FRI sparse sampling directly with hardware circuitry.

We report the synthesis of three-dimensional (3D) urchin-like Nb2O5 microstructures by a facile hydrothermal approach with subsequent annealing treatment. As anode materials for lithium-ion batteries, the 3D urchin-like Nb2O5 microstructures exhibit superior electrochemical performance with excellent rate capability as well as long-term cycling stability. The electrode delivers high capacity of 131 mA h g−1 after 1000 cycles at a high current density of 1 A g−1. The excellent electrochemical performance suggests the 3D urchin-like Nb2O5 microstructures may be a promising anode candidate for high-power lithium ion batteries.

We present another topological superfluid with s-wave pairing for ultracold fermionic atoms in addition to the chiral topological superfluid proposed by Sato et al (2009 Phys. Rev. Lett. 103 020401), of which edge dislocations host Majorana zero modes that may be utilized as decoherence-free qubits, and quantized vortices trap zero energy modes. The quantum phase fluctuations for topological superfluids and Berezinsky–Kosterlitz–Thouless transition are also discussed.

A compact wideband printed antenna fed by coplanar waveguide (CPW) is presented in this paper. The wideband characteristic is achieved by coupling three monopole resonant modes of the proposed antenna. The proposed antenna is built and simulated to verify the design strategy. A wide impedance bandwidth of 100.5% (1.7866-5.3953 GHz) with S11< - 10 dB is achieved. The proposed antenna has stable performance, including bi-directional radiation pattern and gain. It also shows the merits of low cost and simple structure.

Ultrashort multi-ke V x-ray pulses are generated by electron plasma produced by the irradiation of femtosecond pulses on metals. These sub-picosecond x-ray pulses have extended the field of x-ray spectroscopy into the femtosecond time domain. However, pulse-to-pulse instability and long data acquisition time restrict the application of ultrashort x-ray systems operating at low repetition rates. Here we report on the performance of a femtosecond laser plasma-induced hard x-ray source that operates at 1-k Hz repetition rate, and provides a flux of 2.0 × 1010 photons/s of Cu Kαradiation. Using this system for time-resolved x-ray diffraction experiments, we record in real time, the transient processes and structural changes induced by the interaction of 400-nm femtosecond pulse with the surface of a 200-nm thick Au(111) single crystal.

We propose a method to investigate solute transport in dynamically loaded articular cartilage (AC) through phase contrast imaging (PCI) at Shanghai Synchrotron Radiation Facility (SSRF). Six normal human cartilage specimens were immersed in Iopamiro 370 (I370) contrast agent for 48 h. After immersion, a PC image was taken of each specimen to record initial concentrations and was taken again after 1 h of loading. The relationship between image data and contrast agent concentration was determined and image data could be converted into concentration distribution, which was further processed into the transport direction. Results showed that sensitivity interval of the graylevel occurred in the concentration between 0 and 0.1 M. Solute transport mapping indicated that the transport was divided into upper and lower regions whose directions were opposite. The mapping supported the transport path from the bottom of AC, as well as exhibited bi-circulation within AC, which enhanced the transport efficiency in the cartilage matrix.

In this paper we study an s-wave topological superconductor (SC) with a square vortex lattice. We proposed a topological Majorana lattice model to describe this topological state which was supported by the numerical calculations. We found that the Majorana lattice model is really a "topological SC" on the parent topological SC. Such hierarchy structure becomes a new holographic feature of the topological state.

The time evolution of genuine multipartite entanglement is numerically studied in a model many-spin system decohered by a structured spin bath. It is found that multipartite entanglement can be more persistent than the bipartite entanglement and can even evolve into a specific constant under certain conditions. Besides, multipartite entanglement sudden death and sudden birth are observed. It is shown that the randomness of the coupling strength and connectivity between the spins in the environment will suppress these birth and death phenomena. Furthermore, the initial state of the central system plays a significant role in determining multipartite entanglement dynamics.

Using the first-principles methods, we study the formation energetics properties of intrinsic defects, and the charge doping properties of extrinsic defects in transparent conducting oxides CuCrO2. Intrinsic defects, some typical acceptor-type, and donor-type extrinsic defects in their relevant charge state are considered. By systematically calculating the formation energies and transition energy, the results of calculation show that, VCu, Oi, and OCu are the relevant intrinsic defects in CuCrO2; among these intrinsic defects, VCu is the most efficient acceptor in CuCrO2. It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO2 because of their deep transition energy level. For all the acceptor-type extrinsic defects, substituting Mg for Cr is the most prominent doping acceptor with relative shallow transition energy levels in CuCrO2. Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO2.

We prepare an array of amorphous silicon nanopillars by using a modified nanosphere lithography method. The fabrication process includes three steps: (1) 70 nm thick a-Si film was deposited on a crystalline silicon substrate; (2) the substrate was coated with a monolayer of polystyrene (PS) spheres to form an ordered structure on the a-Si thin film surface; (3) the sample was etched by reactive ion etching to produce the amorphous silicon pillar array. The results of field emission measurements show a low turn-on electrical field of about 4.5 V microm(-1) at a current density of 10 microA cm(-2). A relatively high current density exceeding 0.2 mA cm(-2) at 9 V microm(-1) was also obtained. The field enhancement factor is calculated to be about 1240 according to the Fowler-Nordheim (FN) relationship. The good field emission characteristics are attributed to the geometrical morphology, crystal structure and the high density of the field emitter of the silicon nanopillar.