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Superconducting quantum interference devices (SQUIDs) are low-noise amplifiers that are essential for the readouts of translation edge sensors (TESs). The linear flux range is an important parameter for SQUID amplifiers, especially those controlled by high-bandwidth digital flux-locked-loop circuits. A large linear flux range helps to accurately measure the input signal and also allows increasing the multiplexing factor in the time-division multiplexed (TDM) readout scheme of the TES array. We report an improvement of the linear flux range of a SQUID using self-feedback effect. When an asymmetric SQUID loop is designed, a voltage-biased SQUID shows an asymmetric current-flux (I-Φ) response curve. The linear flux range is improved alongside the I-Φ curve with a shallow slope. The experimental results agree well with the numerical simulations. The asymmetric SQUID will sever as a building block in the development of the TDM readout systems for large TES arrays.

Organic single crystals are attracting enormous attention and playing an indispensable role in the realization of high-performance electronic devices. In this paper, we reported an in-situ growth method for two-dimensional branch-like and hexagonal shapes fluoranthene crystals under the photophoretic and dielectrophoretic forces generated by the photothermal and photovoltaic effects in both vapor- and liquid- environments. The crystals grown via this method are characterized by the real-time controllability and large size. At the same time, the crystal morphology can also be modified through non-contact illumination. This growth method may serve the future demand for the crystal growth in different phases.

The understanding of soliton dynamics promotes the development of ultrafast laser technology. High-energy pure-quartic solitons (PQSs) have gradually become a hotspot in recent years. Herein, we numerically study the influence of gain bandwidth, saturation power, small-signal gain, and output coupler on PQSs dynamic in passively mode-locked fiber lasers. The results present that the above four parameters can affect PQS dynamics. Pulsating PQSs occur as alter other three parameters when taken gain bandwidth as 50 nm. Meanwhile, PQSs show an evolution from pulsating to erupting and then to splitting as altered other three parameters when taken gain bandwidth as 10 nm, which can be attributed to the existence of spectral filtering effect and intra-cavity fourth-order dispersion. These findings provide new insights into PQSs dynamics in passively mode-locked fiber lasers.

It is proposed that an energy optimization model of multi energy interaction in thermal power plants with wind power, photovoltaic and hydrogen production and hydrogen fuel cell system (HPHFCS). Considering that the wind power, photovoltaic and HPHFCS are connected to the auxiliary power system of thermal power plant, according to the output characteristics of the multiple power sources and auxiliary power load, an energy optimization model of multi energy interaction at the auxiliary power is proposed and analysed. This paper quantitatively analyses the role of wind power, photovoltaic and HPHFCS connected to the auxiliary power system of thermal power plants in promoting the local consumption of renewable energy sources and reducing the power consumption rate of thermal power plants. Numerical cases and simulation results validate the correctness and effectiveness of the energy optimization model in this paper.

The current status of the regional 10kV distribution network has problems such as the unreasonable capacity declaration, capacity redundancy, and line margin reduction due to a large number of distributed PV and electric vehicle access. In this regard, a redundancy margin analysis method of a 10kV regional distribution network based on demand-side response is proposed. The customer distribution substation power consumption data and operation data are analyzed to establish a 10kV regional distribution network redundancy margin analysis model, and the model is constrained. In the experiments, the proposed method is verified for analysis accuracy. The analysis of the experimental results shows that the proposed method has a high analytical accuracy for analyzing the redundancy margin of the 10kV regional distribution network.

The proximity effect to reduce the transition temperature of a superconducting film is frequently used in transition-edge sensors. Here, we develop these transition-edge sensors using Mo/Au/Au tri-layer films to detect soft x-rays. They are equipped with an overhanging photon absorber. We reduce the fabrication complexity by integrating the sensor patterning with the tri-layer film formation. We determine the electro-thermal parameters of the sensors through a series of resistance vs. temperature and current vs. voltage measurements. We also demonstrate their energy-resolving capability by using a 55Fe radioactive x-ray source. The best energy resolution was approximately 6.66 eV at 5.9 keV, with a theoretical count rate of 500 Hz.

To solve the problem of the low recovery rate of critical loads in the capacity efficiency margin calculation model of the distribution substation area, a data-driven capacity efficiency margin calculation model for the distribution substation area is designed by identifying the data characteristics of customer-side resources in the distribution substation area, approximating the functional relationship between mechanical and electrical energy using segmentation functions, finding the equipment regulation strategies corresponding to historical load sequences from the database, designing a dynamic optimal tide framework using data-driven technology, discovering the shortcomings that limit the performance of network carrying capacity, and constructing a capacity efficiency margin calculation model. Test results: Under three different simulation scenarios, the average values of key load recovery rates of the distribution substation capacity efficiency margin calculation model and the other two models are 64.946%, 56.223%, and 55.024% respectively, indicating that the designed distribution substation capacity efficiency margin calculation model is more effective when fully combined with data-driven technology.

With the rapid development of smart power terminals equipped with embedded operating systems, business APPs have emerged rapidly along with them. Since various business APPs have excessive access to system resources, this will lead to the waste of system resources, and at the same time, the system security is not guaranteed. Therefore, in this paper, based on the context-aware program access control hardware resource framework, an auxiliary tool is designed to control the access of business APPs with excessive authority. The auxiliary tool trains the model through the steps of training sample collection, sample data processing, feature extraction, parameter selection, and model training. By conducting simulation experiments, the results show that by using the auxiliary tool proposed in this paper, the device can well identify the business APPs with excessive privileges and reduce the abuse of related resources with a small load, which has almost negligible impact on the users’ usage.

Research has shown that passively mode-locked fiber lasers produce chaotic output, which has caught the attention of physicists, chemists, and bio-scientists owing to their wide bandwidth, good random characteristics, and strong anti-interference. In passively mode-locked fiber lasers, soliton pulsations and soliton explosions with period bifurcation characteristics have been demonstrated to be effective paths to chaos as far as 20 years ago. However, due to the lack of real-time spectrum measurement techniques, the earlier research investigated their theoretical aspect. In recent years, the rise of the dispersive Fourier transform technique has activated an upsurge of experimental research. The present work first discussed the theoretical model of passively mode-locked fiber lasers, the computational analysis method of soliton dynamics, and the related theory of the dispersive Fourier transform technique. In addition, we presented and evaluated the progress of the theoretical and experimental research on soliton pulsations as well as on soliton explosions in passively mode-locked fiber lasers. Finally, we proposed the future research directions of the soliton pulsations and soliton explosions that offer great promise for scientific discoveries.

YOLO v5 was born when Joseph Redmon, the father of YOLO, announced his retirement from the field of computer vision, and its structure was further optimized on the basis of YOLO v4. After the sort target tracking algorithm was proposed, the deep sort algorithm added the optimization of apparent features on the basis of the sort algorithm, which enables the model to be more suitable for practical situations and more mature for vehicle detection on traffic roads. Focusing on the new direction of road traffic detection, a single camera is used to detect and track dual-channel vehicles. In the process of experimental exploration, a “double vertical line” algorithm is proposed by introducing the attention mechanism into the YOLO v5 structure and combining with the deep sort target tracking algorithm, which provides a new thinking angle and flow chart for vehicle repeat counting. Finally, the detection results of vehicle identity and traffic flow are obtained through experiments, enabling vehicles to be detected and tracked in real time even on roads with a certain speed. In addition, the calculation law avoids the miscalculation of roads with forks, obtains excellent results on vehicle types and traffic flow, and uses id identity to give car information, which significantly improves the possibility that the model can be applied to practical problems.

We have numerically and experimentally observed the soliton pulsation with obvious breathing behavior in the anomalous fiber laser mode-locked by a nonlinear polarization rotation technique. The numerical study of the soliton pulsation with breathing behavior was analyzed through the split-step Fourier method at first, and it was found that the phase difference caused by the polarization controller would affect the breathing characteristics. Then, taking advantage of the dispersive Fourier transform technique, we confirmed the breathing characteristic of soliton pulsation in the same fiber laser as the simulation model experimentally. These results complement the research on the breathing characteristic of soliton pulsation.

Traditional target detection methods have poor tracking effect for targets with excessive displacement or occlusion between adjacent frames, and it is difficult to deal with high-speed moving targets. In view of the low detection rate of the current system in detecting long-distance weak and small targets, false targets and occlusion in the air, the working mode of convolutional neural network (CNN) and its advantages in target detection are analyzed, and a target detection method based on CNN is proposed, which can ensure the target detection accuracy and meet the real-time requirements of combat scenes, Finally, compared with other algorithms, the proposed method achieves the best results on four types of data. While the center error is low, it has high tracking success rate and low time complexity, which meets the requirements of high precision and real-time of the system.

This paper improves the core functions of the real-time video analysis system for edge computing which we proposed before. The improvement of this paper including distributed cluster status management and two-level horizontal expansion. The three-level task scheduling mechanism is realized, and the complete data link processing is realized. At the same time, RK3399pro is proposed to replace RK3399 as the hardware computing unit of the AI business. On the premise of satisfying real-time processing, the computing unit resources are saved. Compared with our previous system, the processing capacity of the new system is improved by 6-8 times.

Aiming at a series of issues on traditional boost converter which commonly used in photovoltaic maximum power point tracking (MPPT) devices, such as the limited output voltage, the low boost efficiency, the excessive heat generating, this paper proposed a novel z-source converter. Compared with traditional boost converter, several researches have done among topology structure, operational principle, boost factor. Based on the theoretic analysis, this paper given two schemes of photovoltaic MPPT system which using boost converter and z-source converter, the models of them are established based on Matlab. The simulation results indicate that the duty-ratio of photovoltaic MPPT system based on z-source converter is smaller, the stability of MPPT is better. The novel z-source converter can fundamentally solve the issues caused by traditional boost converter in photovoltaic MPPT devices, and it has incomparable advantages than traditional boost converter in the field of photovoltaic power generation.

In order to study the effect of blade structures on the induced excitation characteristics, two different structures are investigated, which are the blade with special trailing edge and the staggered blade. Firstly, based on the steady numerical simulation, the time-averaged velocity and pressure distribution are obtained at different Re numbers (5×103 and 1×104). Secondly, the unsteady numerical simulation method LES is applied to acquire the transient and complex flow field around the blade. It is found that both two blade structures significantly change the flow characteristics around the blade, especially in the wake flow region. The evident frequency is observed from the frequency spectrums. It is clear that the dominant frequency is originated from the vortex shedding, which is similar to the Karmen vortex street. Finally, the results will be useful for the design of blade with low noise purpose.

In order to improve the performance of electricity information collection system, this paper studies and proposes a new method of low-voltage power line carrier signal frequency domain noise reduction. It includes frequency domain decomposition of carrier signal, filtering noise reduction and signal frequency domain restoration. Then compared our method with the wavelet packet noise reduction method based on multi-resolution. The experimental results show that the proposed algorithm is better than the comparison algorithm under different modulation modes and carrier frequencies, especially suitable for carrier signal noise reduction under bad channel conditions. The algorithm proposed in this paper has good anti signal attenuation performance, and it can effectively enhance the SNR, and ensure the transmission performance and system reliability of the electricity information collection system.

In view of the development of the city and the development and utilization of underground space, the new building foundation pit is close to the existing foundation pit. In view of this problem, a common reconstruction technology of existing retaining piles under the condition that the new and old foundation pits are adjacent to each other is proposed. The main construction process includes: primary selection of common pile section, design change, bored pile inspection, construction of steel pipe pile with pilot hole, depth judgment of new and old foundation pit, construction of locking anchor rod, foundation pit construction, monitoring and acceptance, etc. The reconstruction and reuse technology of the existing foundation pit supporting pile has been applied in a foundation pit in Zhuhai, which proves that it is safe and reliable, saves the construction period, reduces the construction difficulty, and improves the construction efficiency, which can provide reference for similar projects.

As an important way to solve the problems of urban public transportation, urban rail transit has been comprehensively developed in urban construction. However, the subsequent construction of municipal engineering will affect the deformation of the underlying subway tunnel due to excavation and unloading. Aiming at the excavation of the foundation pit of the upper-span intercity railway tunnel section, by optimizing the construction technology, it is proposed to excavate in stages, small pits and small silos, and Midas GTS is used to establish a finite element model of foundation pit construction. The deformation and force influence of the existing tunnel structure underneath have been analyzed in detail. The method of excavation by stages, small pits and small silos can be used. And the technical methods adopted can reduce the impact of soil unloading on the underlying tunnel and ensure the safety and quality of foundation pit excavation. The project provides a reference basis.

We describe measurements of thermodynamic temperature in the range 5 K to 24.5561 K (the triple point of neon) using single-pressure refractive-index gas thermometry (SPRIGT) with 4He. In the wake of the May 2019 re-definition of the kelvin and its associated mise en pratique, the main purpose of the work is to provide values of T–T 90, the discrepancy between thermodynamic temperature and that of the International Temperature Scale of 1990 (ITS-90). The link to ITS-90 is made via calibrated rhodium-iron resistance thermometers. Innovations required to reach the level of accuracy required for meaningful measurements (uncertainty in T–T 90 less than the expected deviation) include the suppression of temperature oscillations in a cryogen-free cryostat, a pressure stabilization scheme based on a non-rotating piston balance, modelling of the hydrostatic head correction and refinements of the measurement of microwave resonances in a quasi-spherical copper resonator. The accuracy of measurements varies from 0.05 mK to 0.17 mK and is competitive with that of all previous ones in this temperature range using other techniques. The improvement stems partly from the new techniques used for the new definition of the kelvin as well as ab initio calculations of the thermophysical properties ofgaseous 4He. In addition to confirming the validity of SPRIGT as an accurate, easier-to-implement alternative to other low-temperature primary thermometry techniques (e.g. acoustic gas thermometry) yet with scope for improvement, the results should provide important input data for any future revision of ITS-90.

Beijing lake yanxi ecological development demonstration project, a total of 60 square meters, consists of eight 50 tower and garage, tower, a total of seven family, layer number ranged from 8 to 15 layers, structure with shear wall structure, garage mainly adopts frame structure, through the choice of different structure and introduction, the structure system is analyzed.

This paper presents a broadband LNA using 70nm GaAs MHEMT process operating from 1.5GHz to 20GHz. The multi-feedback technique and input/output impedance match are applied to compensate the transistor gain roll-off with frequency and optimize the stability and reflection coefficients. The effect of the multi-feedback technique for stability, noise figure, gain flatness, linearity, and S-parameter performance are analyzed and discussed. Among the whole bandwidth, this LNA features gain of average 29.5dB increasing with frequency and noise figure of average 1.15dB. This LNA also achieves good reflection and isolation performance. The consuming of this LNA is blow 150mW and the chip area is less than 1.4mm*0.8mm. The figure-of-merit (FOM) is about 362.6 (GHz/mW). This LNA could be found its application in high data rate transmission, software defined radio, 5G communication, test instrumentation, wideband radar and other wideband systems.

Formation satellites have configuration requirement. It takes new problem to the automatic process of long term satellite management. Because formation satellites can be managed by inter satellite links for TT&C missions. The complex restricted conditions have been analyzed, including that the execution time and content of TT&C event are various, and time is short for TT&C and so on. A solution of TT&C mission planning is given for formation satellites with multiple constraints. Based on automatic process for multi-satellite management, the formation satellites can be managed automatically for long term. It is applied in the system forsatellite long termmanagement. The result shows that can avoid mistakes caused by manual operation, and improve management efficiency for formation satellites.

Molybdenum disulfide (MoS2) nanosheets showed remarkable catalytic performances and applications because of the excellent catalytic activity at the edge sites. Meanwhile, vertically aligned nanosheets can remarkably increase the surface area within a specific area, making vertical MoS2 nanosheets an ideal electrochemical material. Recently, chemical vapor deposition (CVD) was shown as a reliable method to grow vertical MoS2 nanosheets. Here, the growth of vertical MoS2 nanosheets on various substrates by CVD was reported and the influence of substrates on growth was investigated. Dense vertical MoS2 nanosheets were successfully synthesized on carbon materials, including activated carbon, glassy carbon, carbon paper, graphene and rGO films, but were not observed on GO films, SiO2/Si, glass and ITO. First-principles calculations based on density functional theory suggested that carbon atoms on substrates could facilitate vertical growth of MoS2 nanosheets.

Short-term series forecasting is one of the essential issues in a variety of tasks, such as traffic flow prediction, stock market tendency analysis, etc. Most current methods based on stable or abundant historical data. In this paper, we proposed a novel model called LA-NN. It takes advantages of both long short-term memory (LSTM) network and autoregressive integrated moving average (ARIMA) by a relation integration of them. So as to deal with the situation of insufficient historical data and sudden abnormal changes in data. A comparison with other representative forecast models validates that the proposed LA-NN network can achieve a better performance.

In order to investigate basic output performances of PEMFC (Proton Exchange Membrane Fuel Cell) stack, a dynamic model of PEMFC stack has been developed by combining electrochemical sub-model and thermodynamic sub-model. With necessary validation, it demonstrates that modelling results and experimental data are in very good agreement in terms the U-I curve and power output. By applying the dynamic model to analyse performance outputs of PEMFC stack and applying the model for FC-Hybrid vehicle powertrain configuration, it demonstrates that improved PEMFC quality with increased maximum current density could increase the peak power output and also increase the working efficiency, although the increase of peak power is not linear relation with the increase of maximum current density. Higher working temperature of PEMFC would benefit the increases of both peak power output and efficiency. Compared to working temperature, ambient temperature’s increase could also make positive influence on power output and efficiency, though the influence is weak. Coupling the dynamic model with a powertrain model of FC-Electric hybrid vehicle, the analysis suggests that both PEMFC stack and battery stack should have similar size for general driving condition. Too big either PEMFC stack or battery stack would increase the total weight then contaminate the fuel/energy economy.

In this paper, a broadband low noise amplifier (LNA) is presented with 70nm GaAs metamorphic high electron mobility transistor (MHEMT) process. The feedback and input/output impedance match techniques for broadband amplifier are presented. The stability, noise figure, gain flatness, and S-parameter performance of this LNA are analyzed and discussed. The small signal gain of the LNA is 20dB±0.2dB and noise figure of 0.86dB~1.35dB among operating from almost DC to 15GHz. This LNA exhibits reflection below -10dB, power dissipation of 70mW and chip area of 1.0mm*0.6mm. This LNA finds its application in many wideband systems.

The three-dimensional high-resolution imaging sonar uses multi-beam technology combined with synthetic aperture technology to achieve centimeter-level imaging of small underwater targets. It has a good imaging effect on underwater anchoring, sinking mine and buried mine target detection and underwater topography, and has a wide range of military and civil engineering applications. The system has a large amount of data transmission and computation, including multiple functional modules such as synthetic aperture, high resolution array processing, image processing, and target recognition. The software architecture is complex and real-time system development faces serious challenges. The blade servers have been widely used in the telecommunications, financial and other big data processing fields as for the high efficiency, stability and autonomy. This paper introduces a cluster 3D imaging signal processing system based on x240m5 blade server. The message queue communication (ZMQ) is used to realize the stable transmission of large data volume. At the same time, the mixed programming technology of C language and Matlab language combines the convenience of real-time and software integration, which greatly shortens the development cycle. The system runs stably and realizes the imaging recognition of the small spheres and their clump weights in the simulated target water.

Multi-path effecting and Dopplereffecting on missile-borne tester signal transmission based onZigbee application was researched. The maximum transmission distance was derived based on communication channel loss model and multi-path model. The effecting of multi-path on transmission distance was discussed. The effecting of Doppler shift was researched by speed of rocket sled and receiver position. Transmission speed and error rate of missile-borne tester was studied by Doppler effecting. The measure which reduced multi-path fading and Doppler effecting was gained. These can advance signal transmission quality and improve revamping of equipment.

In the present work, Mo4O11 @MoO3 nanobelts are successfully prepared by a two-step hydrothermal method. The nanobelts are about several micrometers in length and 200–300 nm in width with Mo4O11 nanoparticle on surface. The introduction of nanoparticles act as the adsorption sites which facilitate the adsorption of O2 and NO2 gas molecules, because of the point defects such as Mo5+ ions and oxygen vacancies inducing to increase the concentration of carriers, which synthetically contribute the sensing performance enhancement. The Mo4O11@MoO3 nanobelts show excellent sensing performance with 6 times enhancement with the decreased working temperature comparing with the pure α-MoO3 nanobelts. This study indicate that this kind of sensor show a promising application in NO2 detection.

Given a family of vector fields parametrized by ? in its linear part, one usually obtains its versal unfolding by the so-called two-step approach, i.e. find a Poincar? normal form for the system with fixed ?0 and then apply the obtained near-identity transformation to the system with general ?. It is also a common practice to treat ? as a component together with those state components and calculate normal forms of the extended system. In this paper we reformulate normal forms on modules of homogeneous polynomials over the ring of all continuous functions of ? and give a direct computation of versal unfolding. Our procedure enables us to determine coefficients of all terms of a certain degree in the normal form before we give a near-identity transformation of this degree. We can give all available near-identity transformations and choose an appropriate one to eliminate more terms of higher degree for a simpler normal form. We prove that the normal form reduced in our procedure is the simplest and unique. We illustrate our method with systems of linear centre and nilpotent linear parts separately.

The three-dimensional turbulent flow around plate cascades in staggered is an important factor to induce hydro-mechanical vibration. Taking the upstream three plates in side-by-side configuration and the downstream single plate in tandem configuration to form the overall staggered layout of the cascades as the subject of investigation. Based on the Large-Eddy-Simulations (LES), the forces experienced by the plates, velocity distributions and three-dimensional vortex structures around the plates are analysed in detail. Some experiments were also carried out to validate the accuracy of the numerical results by LDA measurement. The mean velocity distributions from LES results agree fairly well with the experimental results. Results show that the existence of the downstream plate hinders the development of the upstream wake and has a significant inhibitory effect on the forces experienced by the upstream plates; When the gap spacing is smaller, the stream-wise length of the reverse flow region between the upstream and downstream plate becomes larger, and the minimum velocity in this region is lower than other reverse flow regions; The flow around the plate cascades exhibits high three-dimensional characteristics, and the amplitude of the fluctuation of the forces on the downstream plate under the interference of the upstream wakes is increased obviously. The downstream plate is located in the wake of the upstream cascade, and has a steady flow to the upstream wake. Analysis on the flow can provide theoretical support for the flow control in hydraulic machinery.

The aim of this study is to investigate the effects of different packing materials on cotton fires. After the cotton bale is ignited, the caving area, the mass loss rate and the temperature variation of cotton bales were measured. Through the experiment, it was found that Cotton bale packed with Plastic belt has the phenomenon of collapse, but the cotton bale packed with Steel ribbon does not happen to collapse. The mass loss rate of the Cotton bale packed with Plastic belt is faster than that of the cotton bale packed with Steel ribbon, and the temperature is higher.

This paper describes a negative nanoimprint lithography (N-NIL) technique for fabricating metallic nanostructures via combining conventional nanoimprint lithography (NIL) with wet chemical etching. Various metallic nanostructures such as gold grating, gold/chromium alternate bimetallic grating and gold nanoelectrode arrays, which are negative replications of the stamp pattern, have been fabricated with N-NIL. This method has demonstrated its advantages on varying the feature size of obtained metallic nanostructures with a single stamp as well as on fabricating bimetallic nanostructures. In addition, it offers a unique path to fabricate micro?nano complex structures in a single imprint process, which compensates the limitation of conventional nanoimprint lithography and maintains the advantages of conventional nanoimprint lithography such as high throughput, low cost and sub-100?nm resolution.

We discuss the relationship between scattering length and binding energy for a diatomic system with long-range van der Waals interaction. The well-known relation, 0 = −(2/2μ)(1/a0)2, is generalized to much higher orders for the s wave. Analytic results for the binding energies of p and higher angular momentum states are also presented.

We show that universal properties of a many-atom quantum system exist at a much higher density, or a much shorter length scale, than those implied by traditional theories for a dilute Bose gas. In particular, a universal equation of state at length scale β6 = (mC6/2)1/4 (corresponding to the van der Waals interaction) is defined and investigated by combining the concept of effective potential, the constrained variational method and the analytic solution for the van der Waals potential. In one application, we show that a many-atom Bose system with negative scattering length may form a metastable liquid Bose–Einstein condensate (BEC) state with an equilibrium density that is controlled by a scaled scattering length.