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The self-similarity, high geometric symmetry and spatial utilization properties of fractal structures provide new methods for the development of absorbing metamaterials. In this paper, the microwave absorption properties of the gradient dendritic fractal metamaterial structure (GDFMs) based on carbon black and acrylonitrile–butadiene–styrene composites were investigated. The optimal metamaterial structure has an effective absorption in the frequency range of 4.5–40 GHz. The rotational-symmetry GDFMs leads to the polarization independence, and the GDFMs exhibits a wide-angle absorption performance for both TE and TM waves. It is expected that the proposed GDFMs has good application prospects in electromagnetic wave absorption.

As the most common malignancy in the endocrine system, thyroid cancer is often determined based on ultrasound images by professional radiologists based on ultrasound images. In this study, a cascade automatic classification system (CACS) is proposed to accurately achieve automatic segmentation and classification of thyroid nodules, reducing over-reliance on experienced doctors in the diagnosis. Firstly, the Res-UNet is used to segment the region of interest (ROI) of thyroid nodules in ultrasound images. Then, to overcome the limitations of the small sample size of medical training data as well as category imbalance, the modified Conditional Variational Auto-Encoder (CVAE), learning the probability distribution of the ultrasound images, is trained to produce new medical ultrasound images for ROI data augmentation. Finally, we perform the classification task by a three-branch ensemble network combined with clinical diagnostic features of thyroid nodule such as the aspect ratio, internal and external echoes, and edges. The proposed CACS can identify benign and malignant thyroid nodules with an accuracy of 0.892 and an AUC of 0.887, according to testing on real patient data.

In the recycling process of lithium-ion battery, the poor external environment will lead to the degradation of battery performance, so it is necessary to predict the residual life of lithiumion battery. However, the aging cycle of lithium-ion battery is long, so it is difficult to obtain sufficient aging data in a short time. Aiming at the problem of low prediction accuracy of lithium battery residual life under the condition of small samples, a BP neural network modelling algorithm fused with expert knowledge is proposed. Firstly, indirect health factors were extracted from the aging data of lithium battery in NASA PCOE laboratory. Secondly, the initial weight and threshold of BP neural network were optimized by genetic algorithm, and the initial multiplier value of the augmented Lagrange function was set according to Spearman correlation coefficient. Finally, the expert knowledge is integrated into the training process of BP neural network through the augmented Lagrange multiplier method. Simulation results show that the proposed algorithm has higher prediction accuracy than the traditional BP neural network under the condition of small samples.

Proton conducting ceramics show promise in fuel cells, electrolyzers, permeation membranes, sensor applications, and membrane reactors. Among several types of materials that exhibit proton conduction, perovskite oxides show high proton conductivity at intermediate temperatures, presenting potential benefits for long-term use and lower costs for energy applications. Doped barium zirconate, BaZrO3, is a material that has shown high proton conductivity with encouraging chemical stability. Therefore, it is considered a promising material especially for proton-conducting solid oxide electrochemical cells. Although the proton conduction of doped BaZrO3 has been extensively characterized, the specific phenomena behind its proton conduction are not fully understood. Only recently have specialized techniques and computational tools begun to elucidate the phenomena that determine the conduction properties of the material. In this mini review, an evaluation of the factors affecting the proton conductivity of doped BaZrO3 perovskites and the phenomena governing variations in proton concentration and mobility are presented. Special attention is given to proton interactions with dopants and their resulting effect on hydration and transport properties. Technical strategies are provided to give some guidance on the development of protonic ceramics in energy conversion applications.

In the context of my country’s full effort to build pumped storage power stations, my country has the ability to independently research and develop pumped storage power stations, and has set a development goal to manufacture pumped storage units with larger single-unit capacity and higher speed. Generator motors play an important role in the safe and stable operation of power systems, and have a significant impact on power grids and power stations. This paper establishes a physical model of the damping winding of the generator motor, simulates the change of electrical parameters when a short-circuit fault occurs in the no-load operation of the generator motor, and obtains and analyzes the change rule, which has great theoretical and practical significance.

The pumped storage power station is an inevitable product of the power system structure and power supply demand development to a certain stage, and it is a necessary management tool to ensure the safe and stable operation of the power system. Pumped storage power plants have the ability to improve and balance the load of the power system, which can improve the quality of power supply to the power grid and improve overall economic benefits. With the development of high-tech industries such as informatization and digitization and the improvement of people’s living standards, society has higher and higher requirements for pumped storage power stations. Pumped storage motor is a three-phase salient-pole synchronous motor used in pumped storage power stations. This paper simulates and analyzes the stator voltage, current and electromagnetic torque when single-phase grounding short circuit, inter-phase short circuit, and two-phase grounding short circuit occur in pumped-storage motors, and the law of change is obtained.

Nowadays, microsimulation method has been introduced to different fields, such as Social Science, Medicine research and Economic study. This method evaluates the effects of the proposed interventions or policies before they are implemented in the real world. In this article, we will concentrate on microsimulation method used in Social Science by firstly explaining two main streams in microsimulation world, Static approach and Dynamic approach. In the following section, the uncertainty of a Finnish static microsimulation model JUTTA is assessed and Toimtuki model, one of the sub-models in JUTTA is detected to have space to be more accurate. In order to do so, two experimental statistical models-Linear Regression model and Two-Stage Least Squares(2SLS) model are applied to it. From the results, we could conclude that both the Linear Regression and 2SLS successfully improves the accuracy of TOIMTUKI to some extent.

This study aims to increase the amount of electrical energy harvested from a piezoelectric vibration energy harvester under unloaded and high-load resistance conditions. Although increased piezoelectric charge due to the synchronized switch harvesting on inductor (SSHI) strategy damps mechanical vibrations, the mechanical vibration amplitude of a mechanical element in a harvester is assumed to be constant for most discussions regarding the active harvester with SSHI strategy. However, this assumption is not valid under excessive switching actions, in which case the performance of the harvester deteriorates. This problem is known as the vibration suppression effect. To address this problem, in this study, two switching strategies for the charge inversion circuit—namely, switching considering vibration suppression-threshold (SCVS-t) and adaptive SCVS-t (ASCVS-t)—are proposed through intermittent switching actions. During the harvesting process, intermittent switching using these strategies is performed based on the output voltage threshold, thus maintaining high mechanical vibration amplitude and excellent harvesting performance by avoiding excess switching. The ASCVS-t adopts a tuning algorithm for the time-varying threshold and can achieve appropriate intermittent switching and effective harvesting under various vibration conditions without pre-tuning. Experimental comparisons with conventional strategies confirm that the proposed strategies achieve 2.9 times and 2.0 times greater harvested energy storages than a standard harvester and conventional switching strategy, respectively.

Geological Cloud 2.0 is a comprehensive upgrade of data resources and systems on the Geological Cloud 1.0. As one of its distributed nodes, geological environment sub-node provides data sharing services in the geological environment for Geological Cloud 2.0. In order to better serve the comprehensive sharing of Geological Cloud 2.0 data resources, the specific technical implementation of Geological Cloud 2.0 geological environment sub-node data sharing was introduced with shared data. The construction effect of this node was introduced. The results show that the data sharing implementation technology of geological environment sub-node provides reference experience for Geological Cloud 2.0 construction and upgrading in the future.

We performed a detailed electrical transport study at very high magnetic fields and low temperatures in high quality single crystals of Sr4Ru3O10. When the field is applied along the inter-plane direction Shubnikov-de Hass oscillations are observed showing that a metamagnetic transition leads to a quite non-trivial evolution of the geometry of the Fermi surface. It can be ascribed either that localized and itinerant bands coexist in this system, the former leading to the ferromagnetic response and the latter to itinerant metamagnetic behavior, or that itinerant metamagnetism emerges from a Stoner-like ferromagnetic ground state.

A highly efficient, fully parallelized, fully relativistic, three-dimensional particle-incell model for simulating plasma and laser wakefield acceleration is described. The model is based on the quasi-static approximation, which reduces a fully three-dimensional electromagnetic field solve and particle push to a two-dimensional field solve and particle push. This is done by calculating the plasma wake assuming that the drive beam and/or laser does not evolve during the time it takes for it to pass a plasma particle. The complete electromagnetic fields of the plasma wake and its associated index of refraction are then used to evolve the drive beam and/or laser using very large time steps. This algorithm reduces the computation time by 2 to 3 orders of magnitude without loss of accuracy for highly nonlinear problems of interest. The code is fully parallelizable with different domain decompositions for the 2D and 3D pieces of the code. The code also has dynamic load balancing. We present the basic algorithms and design of QuickPIC, as well as comparison between the new algorithm and conventional fully explicit models (OSIRIS). Direction for future work is also presented including a software pipeline technique to further scale QuickPIC to 10,000+ processors.

Plasma-based lepton acceleration concepts are a key element of the long-term R&D portfolio for the U.S. Office of High Energy Physics. There are many such concepts, but we consider only the laser (LWFA) and plasma (PWFA) wakefield accelerators. We present a summary of electromagnetic particle-in-cell (PIC) simulations for recent LWFA and PWFA experiments. These simulations, including both time explicit algorithms and reduced models, have effectively used terascale computing resources to support and guide experiments in this rapidly developing field. We briefly discuss the challenges and opportunities posed by the near-term availability of petascale computing hardware.

In this paper, polymethacrylate enteric coated materials based on the equal mass of methyl acrylic acid and ethyl acrylate as the main raw materials were synthesized through emulsion polymerization. Omeprazole Enteric-coated Capsules were prepared by the fluidized bed coating technology using above materials as enteric layer and in vitro enteric test was considered according to standard. The results showed that the material had good coverage in the surface of omeprazole isolated pellets, excellent acid resistance in artificial gastric acid environment, and reached the disintegration effect in the buffer solution of 20min. Moreover the drug release reached 88.2% and had excellent long-term storage.

This paper proposes an H−/H∞ fault detection observer design method by using generalized output for a class of polytopic linear parameter-varying (LPV) system. First, with the aid of the relative degree of output, a new output vector is generated by gathering the original and its time derivative. The actuator fault is introduced into the measurement equation of the new system. An H−/H∞ observer is designed for the new LPV polytopic system to guarantee the robustness against disturbances and to improve the fault sensitivity, simultaneously. The existence conditions of the H−/H∞ observer are given and solved by a set of linear matrix inequalities (LMIs). Finally simulation results are given to illustrate the effectiveness of the proposed method.

A novel mechanical anti-aliasing filtering fibre-optic hydrophone with a cylindrical Helmholtz resonator is constructed and tested. The experimental results show that the hydrophone has a function of low-pass filtering. The low frequency acoustic sensitivity is about −160 dB (1 rad/μPa), and the response curve has a resonance determined by the Helmholtz resonator. Theoretical and experimental results both show that the resonant frequency moves towards high frequency with the increasing orifice diameters. The sensitivity attenuation of high frequency is larger than 10 dB. This new fibre-optic hydrophone is a prototype device for a class of sensors used to eliminate the aliasing in future sonar systems.

For distributed fiber Raman amplifiers (DFRAs), stimulated Brillouin scattering (SBS) can deplete the pump once occurring and consequently generate gain saturation. On the basis of such a theory, theoretical gain saturation powers in DFRAs with various pump schemes are obtained by calculating SBS thresholds in them, and the experimental results show that they are in excellent agreement with the calculation results. The saturation power of the DFRA with a 300 mW forward pump is as low as 0 dBm, which needs to be enhanced by phase modulation, and the effect is quantitatively studied. A simple model taking both modulation frequency and index into consideration is presented by introducing a correction factor to evaluate the effect of phase modulation on the enhancement of saturation power. Experimentally, it is shown that such a correction factor decreases as the modulation frequency increases and approaches zero when the modulation frequency becomes high enough. In particular, a phase modulation with a modulation frequency of 100 MHz and a modulation index of 1.380 can enhance the saturation power by 4.44 dB, and the correction factor is 0.25 dB, in which the modulation frequency is high enough. Additionally, the factor is 1.767 dB for the modulation frequency of 25 MHz. On this basis, phase modulations with various indexes and a fixed frequency of 25 MHz are adopted to verify the modified model, and the results are positive. To obtain the highest gain saturation power, the model is referable. The research results provide a guide for the design of practical DFRAs.

Recent studies show that the out-of-plane quadrupolar magnetic field in fast magnetic reconnection is distorted in the presence of a guide field. It is asymmetric with respect to the current sheet. In this work, we analyze the spatial and amplitude asymmetries of the Hall magnetic field By and the Hall electric field Ez in reconnection with different guide fields by a series of 2.5-D particle-in-cell simulations. We derive the relation between the asymmetry of By and Ez and the guide field strength. In addition, by analyzing the different terms in the generalized ohm's law, we find that the electric field Ez is mainly balanced by the Hall term, and the amplitude asymmetry is mainly caused by the Hall effect.

Four-wave mixing, as well as its induced intensity noise, is harmful to wavelength division multiplexing systems. The efficiency and the relative intensity noise of four-wave mixing are numerically simulated for the two-wave and the three-wave fiber transmissions. It is found that the efficiency decreases with the increase of both the frequency spacing and the fiber length, which can be explained using the quasi-phase-matching condition. Furthermore, the relative intensity noise decreases with the increase of frequency spacing, while it increases with the increase of fiber length, which is due to the considerable power loss of the pump light. This investigation presents a good reference for the practical application of wavelength division multiplexing systems.

A sharp dipolarization front (DF) has recently been detected in the Earth's magnetotail and is associated with complex kinetic effects. We present one event where a tailward propagating negative DF (with Bz decreasing sharply to negative value) was observed near a reconnection region. The thickness of the negative DF is comparable with the local ion gyro-radius/inertial length. There is a strong field-aligned current at the front. Electromagnetic whistler wave enhancements are observed around the front, associated with counter-streaming electron beams. We further compare the features of the observed negative DF with the recent kinetic simulation results, as well as the Earthward propagating DFs observed by the THEMIS spacecraft.

We present plasma wakefield acceleration experimental results showing that the energy gain by 28.5GeV electrons scales with plasma length and reaches 14GeV over a plasma with a density of 2.6◊10 17 cm 3 and a length of 31cm. At this plasma density the average accelerating gradient is 36GeVm 1 . These results are in good agreement with the numbers obtained from particle in cell simulations describing the experiment. The linear scaling is also observed both at lower and higher plasma densities, at which smaller energy gains and accelerating gradients are measured. The systematic measurements of energy gain show the reproducibility and control of the acceleration process.

Accelerators are the largest and most costly scientific instruments of the Department of Energy, with uses across a broad range of science, including colliders for particle physics and nuclear science and light sources and neutron sources for materials studies. COMPASS, the Community Petascale Project for Accelerator Science and Simulation, is a broad, four-office (HEP, NP, BES, ASCR) effort to develop computational tools for the prediction and performance enhancement of accelerators. The tools being developed can be used to predict the dynamics of beams in the presence of optical elements and space charge forces, the calculation of electromagnetic modes and wake fields of cavities, the cooling induced by comoving beams, and the acceleration of beams by intense fields in plasmas generated by beams or lasers. In SciDAC-1, the computational tools had multiple successes in predicting the dynamics of beams and beam generation. In SciDAC-2 these tools will be petascale enabled to allow the inclusion of an unprecedented level of physics for detailed prediction.