Search

Low-energy electron collisions with normal-pentane (n-C5H12) that initiate the plasma to assist combustion are critical in understanding the underlying physics and chemistries. In the present work, we studied this collisional process using the R-matrix method at the static-exchange plus polarization and close-coupling model levels. The scattering calculation was performed by running the UKRmol+ code using the Quantemol Electron Collision interface to obtain elastic differential, momentum transfer, integral, and electronic excitation cross sections up to 20 eV and ionization cross sections up to 1000 eV. Our computed cross-section data are in better agreement with the available experimental results both regarding the magnitude and shape. We also demonstrated the importance of using a diffuse basis set in describing the scattering due to the Rydberg nature of the lowest unoccupied molecular orbitals of n-C5H12.

We studied the magnetic properties and domain evolution of the annealed and TbF3-diffused sintered Nd–Fe–B magnets using electrophoretic deposition method. After TbF3 diffusion, the coercivity increased significantly and the increment was 9.9 kOe, and microstructure analysis suggested that Tb favored to form the (Nd, Tb)2Fe14B shell phase in the outer region of the matrix grains. The first magnetization reversal and the dynamic successive domain propagation process was detected through the magneto-optical Kerr microscope. For the TbF3-diffused magnet, the magnetization reversal appeared at a larger applied field and the degree of simultaneous magnetization reversal decreased compared to the annealed magnet. During demagnetization after being fully magnetized, the formation of domain wall motion (DWM) in reproduced multi-domain regions was observed by the step method. And the maximum polarization change resulted from the reproduced DWM was inversely related to the coercivity. The increment of coercivity for the diffused magnet was mainly attributed to the harder nucleation of the magnetic reversed region owing to the improved magnetocrystalline anisotropy field by Tb diffusion.

The effects of doped CeO2 on the magnetic properties and microstructure are studied in 2:17 type SmCo magnets. With the increase of CeO2 from 0 wt.% to 3 wt.%, the coercivity of magnets increases from 22.22 kOe to over 29.37 kOe, which is an increase of more than 30%. When the doping content is lower than 1 wt.%, the remanence and magnetic energy product of the magnet remain almost constant. Both decrease sharply as the doping concentration further increases. After CeO2 doping, the oxide content in the magnet increases significantly and the Ce element is uniformly distributed in the magnet. Observing the magnetic domain reveals that doping CeO2 can refine the magnetic domains and make the magnetic domain wall more stable, resulting in a significant increase in the coercivity of the magnets.

Magnetic microbubbles (MMBs) can be controlled and directed to target site by a suitable external magnetic field, have potential in therapeutic drug-delivery application. However, few studies focus on their dynamics in blood vessels under the action of magnetic and ultrasonic fields, even little insight into mechanism generated in diagnostic and therapeutic application. In this case, equations of MMBs were established for simulating translation, radial pulsation and the both coupled effect. Meanwhile, the acoustic streaming and shear stress on vessel wall were also presented, which are associated with drug release. Results suggest that the magnetic pressure increases bubble pulsation amplitude, and the translation coupled with pulsation are manipulated by magnetic force, causing the retention in target area. As the bubble approaches the vessel wall, the acoustic streaming and shear stress increase with magnetic field enhancement. Responses of bubble to a uniform and a gradient magnetic field were explored in this work. The mathematical models derived in this work could provide theoretical support for experimental phenomenon in literature and also agree with the reported models.

Full list of authors: Bao, Dong-Wei; Brotherton, Michael S.; Du, Pu; McLane, Jacob N.; Zastrocky, T. E.; Olson, Kianna A.; Fang, Feng-Na; Zhai, Shuo; Huang, Zheng-Peng; Wang, Kai; Zhao, Bi-Xuan; Li, Sha-Sha; Yang, Sen; Chen, Yong-Jie; Liu, Jun-Rong; Yao, Zhu-Heng; Peng, Yue-Chang; Guo, Wei-Jian; Songsheng, Yu-Yang; Li, Yan-Rong; Jiang, Bo-Wei; Kasper, David H.; Chick, William T.; Nguyen, My L.; Maithil, Jaya; Kobulnicky, H. A.; Dale, D. A.; Hand, Derek; Adelman, C.; Carter, Z.; Murphree, A. M.; Oeur, M.; Schonsberg, S.; Roth, T.; Winkler, Hartmut; Marziani, Paola; D'Onofrio, Mauro; Hu, Chen; Xiao, Ming; Xue, Suijian; Czerny, Bozena; Aceituno, Jesus; Ho, Luis C.; Bai, Jin-Ming; Wang, Jian-Min; MAHA Collaboration.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., In this third paper of the series reporting on the reverberation mapping campaign of active galactic nuclei with asymmetric Hβ emission-line profiles, we present results for 15 Palomar–Green quasars using spectra obtained between the end of 2016–2021 May. This campaign combines long time spans with relatively high cadence. For eight objects, both the time lags obtained from the entire light curves and the measurements from individual observing seasons are provided. Reverberation mapping of nine of our targets has been attempted for the first time, while the results for six others can be compared with previous campaigns. We measure the Hβ time lags over periods of years and estimate their black hole masses. The long duration of the campaign enables us to investigate their broad-line region (BLR) geometry and kinematics for different years by using velocity-resolved lags, which demonstrate signatures of diverse BLR geometry and kinematics. The BLR geometry and kinematics of individual objects are discussed. In this sample, the BLR kinematics of Keplerian/virialized motion and inflow is more common than that of outflow. © 2022. The Author(s). Published by the American Astronomical Society., We acknowledge the support by the National Science Foundation of China through grants NSFC-12022301, -11991051, -11991054, -11873048, -11833008, by National Key R&D Program of China (grants 2016YFA0400701), by grant No. QYZDJ-SSW-SLH007 from the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), by the Strategic Priority Research Program of CAS grant No.XDB23010400, and by the International Partnership Program of CAS, grant No.113111KYSB20200014. L.C.H. was supported by the National Science Foundation of China (11721303, 11991052) and the National Key R&D Program of China (2016YFA0400702). M.B. enjoyed support from the Chinese Academy of Sciences Presidents International Fellowship Initiative, grant No. 2018VMA0005. YRL acknowledges financial support from the National Natural Science Foundation of China through grant NSFC-11922304 and from the Youth Innovation Promotion Association CAS. H.C. acknowledges financial support from grant NSFC-12122305. We also acknowledge support from a University of Wyoming Science Initiative Faculty Innovation Seed grant. This work is supported by the National Science Foundation under REU grant AST 1852289. T.E.Z. acknowledges support from NSF grant 1005444I., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

With the proposal of the dual-carbon target, renewable energy generation cannot meet the requirements of flexible grid dispatching as traditional power generation energy. Therefore, the proposal of storage energy has become an important development direction. This paper established an optimal configuration model which is applicable to high-proportion photovoltaic power. Then, the rationality of the scheme is evaluated through complementary effects. In the end, the feasibility of the model proposed in this paper is proved by practical cases. The results show that the model can alleviate the peak shaving task undertaken by energy storage, avoid excessive allocation, and reflect the difference in energy storage allocation in various cities.

This study is started from a photon-magnon model with a competition effect of the level attraction and repulsion, its Hermiticity is mainly decided by a phase-dependent and asymmetric coupling factor, namely φ = 0 for Hermitian and ϕ = π for non-Hermitian. Then an extensional study predicts the quantum critical behaviors using an Hermitian and even no-Hermitian photon-spins model with an additional second-order drive. The numerical results firstly indicate that this coupling phase φ can function the protective effect on quantum phase transitions (QPTs), and the new tricritical points can not only be modulated by this nonlinear drive, but also be influenced by the dissipation and the collective decoherence. Secondly, this competition effect can also induce a reversal of the value of order parameters between the positive and negative. This study can also bring more important results of QPTs toward the issue of symmetry breaking and non-Hermiticity.

The layered pavements usually exhibit complicated mechanical properties with the effect of complex material properties under external environment. In some cases, such as launching missiles or rockets, layered pavements are required to bear large impulse load. However, traditional methods cannot non-destructively and quickly detect the internal structural of pavements. Thus, accurate and fast prediction of the mechanical properties of layered pavements is of great importance and necessity. In recent years, machine learning has shown great superiority in solving nonlinear problems. In this work, we present a method of predicting the maximum deflection and damage factor of layered pavements under instantaneous large impact based on random forest regression with the deflection basin parameters obtained from falling weight deflection testing. The regression coefficient R 2 of testing datasets are above 0.94 in the process of predicting the elastic moduli of structural layers and mechanical responses, which indicates that the prediction results have great consistency with finite element simulation results. This paper provides a novel method for fast and accurate prediction of pavement mechanical responses under instantaneous large impact load using partial structural parameters of pavements, and has application potential in non-destructive evaluation of pavement structure.

In view of the inherent poor tribological properties of copper, the reinforcement of copper matrix composites with WC particles presents a promising research area with significant industrial influence. Therefore, in the present study, a molecular dynamics approach is used to simulate the process of repeated friction of diamond grinding balls on WC/Cu composites, and the friction force, friction coefficient, abrasion depth, wear rate, abrasion morphology, von-Mises stress, internal defects, workpiece energy, and performance comparison of different layer thicknesses are systematically investigated in the multiple friction process. It is found that the fluctuation amplitude of friction force, friction coefficient, and abrasion depth are smaller and the fluctuation frequency is larger during the initial friction, whereas near the WC phase, there appears extreme values of the above parameters and the von-Mises stress is highly concentrated while the workpiece energy contonues to increase. In the case of the repeated friction, with the increase of friction times, the friction force, friction coefficient, and abrasion depth fluctuation amplitude increase, the fluctuation frequency decreases, the workpiece energy reaches an extreme value near the WC phase, and a large number of dislocations plug, therefore, the region is strengthened. As the distance between the grinding ball and the WC phase decreases, the more obvious the strengthening effect, the stronger the ability of workpiece to resist the wear will be.

A viable strategy for enhancing photovoltaic performance is to comprehend the underlying quantum physical regime of charge transfer in a double quantum dots (DQD) photocell. This work explored the photovoltaic performance dependent spatially correlated fluctuation in a DQD photocell. The effects of spatially correlated fluctuation on charge transfer and output photovoltaic efficiency were explored in a proposed DQD photocell model. The results revealed that the charge transport process and the time to peak photovoltaic efficiency were both significantly delayed by the spatially correlated fluctuation, while the anti-spatially correlated fluctuation reduced the output peak photovoltaic efficiency. Further results revealed that the delayed response could be suppressed by gap difference and tunneling coefficient within two dots. Subsequent investigation demonstrated that the delayed response was caused by the spatial correlation fluctuation slowing the generative process of noise-induced coherence, which had previously been proven to improve the quantum photovoltaic performance in quantum photocells. And the reduced photovoltaic properties were verified by the damaged noise-induced coherence owing to the anti-spatial correlation fluctuation and a hotter thermal ambient environment. The discovery of delayed response generated by the spatially correlated fluctuations will deepen the understanding of quantum features of electron transfer, as well as promises to take our understanding even further concerning quantum techniques for high efficiency DQD solar cells.

Dielectric polymer-based composites have demonstrated enormous promise in the applications of electrostatic film capacitors due to their exceptional insulating characteristics. However, the achievement of great energy-storage density (U e) is always difficult in linear dielectric polymer-based composites for operation at weak field strength due to the low permittivity (ϵ r) and electric displacement difference (D max − D rem) values. Here, a tri-layered configuration of multicomponent polymeric films is proposed. The outer layers of the tri-layered composite are linear dielectric polymethyl methacrylate (PMMA), and the inner layer is a nonlinear polymer incorporating a low number of polydopamine-modified barium titanate particles (BT@PDA). An increased ϵ r of 8.9@1 kHz is achieved in the designed composite featuring only 2 wt% BT@PDA fillers, equivalent to 234% of the PMMA (∼3.8@1 kHz) matrix. An improved U e of 9.3 J cm−3 at 340 MV m−1 is endowed in the designed film, implying an enormous ∼343% increment of the energy storage compared to the benchmark biaxially oriented polypropylene (∼2.1 J cm−3 at 300 MV m−1). All these advantages present a practical strategy for supplying linear dielectric polymer-based composites with anticipative capacitive energy-storage properties for operation at weak field strengths.

As a high-standard verdant method of transportation, electric-powered-vehicles have become the development hotspot of the automotive business in recent years. Large scale access to electric-powered vehicles can form a distributed energy storage system, which can improve the operational performance of power grid peak shaving and frequency modulation, and improve the comprehensive utilization efficiency of system energy. But at the same time, large-scale electric-powered vehicles connected to the DC distribution network will have a certain impact on its topology. Therefore, this paper studies the impact of the access location and number of electric-powered vehicles on the network topology and establishes a multi-dimensional evaluation system of the DC distribution network topology. The application of this result can play an evaluation and guidance role in the operation stability of the DC distribution network in the case of large-scale access to electric-powered vehicles.

A set of rare earth electrolysis equipment monitoring systems based on OPC unified architecture is proposed given the complex environment of the rare earth electrolysis workshop, the difficulty of data acquisition, and the interconnection between equipment. The monitoring client of rare earth electrolysis equipment based on OPC UA communication protocol is designed and developed with C # language. The connection between the OPC UA server and the monitoring system is realized, and the data acquisition and real-time monitoring of the running state of the electrolysis equipment are completed. The primary goal of the rare earth electrolysis field equipment is to acquire and monitor rare earth electrolysis process current, voltage, and other internal state data in real-time.

In the archive of the Ground Wide Angle Camera (GWAC), we found 43 white light flares from 43 stars, among which, three are sympathetic or homologous flares, and one of them also has a quasi-periodic pulsation with a period of $13.0\pm1.5$ minutes. Among these 43 flare stars, there are 19 new active stars and 41 stars that have available TESS and/or K2 light curves, from which we found 931 stellar flares. We also obtained rotational or orbital periods of 34 GWAC flare stars, of which 33 are less than 5.4 days, and ephemerides of three eclipsing binaries from these light curves. Combining with low resolution spectra from LAMOST and the Xinglong 2.16m telescope, we found that $L_{\rm H\alpha}/L_{\rm bol}$ are in the saturation region in the rotation-activity diagram. From the LAMOST medium-resolution spectrum, we found that Star \#3 (HAT 178-02667) has double H$\alpha$ emissions which imply it is a binary, and two components are both active stars. Thirteen stars have flare frequency distributions (FFDs) from TESS and/or K2 light curves. These FFDs show that the flares detected by GWAC can occur at a frequency of 0.5 to 9.5 yr$^{-1}$. The impact of flares on habitable planets was also studied based on these FFDs, and flares from some GWAC flare stars may produce enough energetic flares to destroy ozone layers, but none can trigger prebiotic chemistry on their habitable planets., Comment: 20 pages, 9 figures, 3 tables

A grain boundary diffusion (GBD) process with Pr80 – x Al x Cu20 (x = 0, 10, 15, 20) low melting point alloys was applied to commercial 42M sintered Nd–Fe–B magnets. The best coercivity enhancement of a diffused magnet was for the Pr65Al15Cu20 GBD magnet, from 16.38 kOe to 22.38 kOe. Microstructural investigations indicated that increase in the Al content in the diffusion source can form a continuous grain boundary (GB) phase, optimizing the microstructure to enhance the coercivity. The coercivity enhancement is mainly due to the formation of a continuous GB phase to separate the main phase grains. Exchange decoupling between the adjacent main phase grains is enhanced after the GBD process. Meanwhile, the introduction of Al can effectively promote the infiltration of Pr into the magnet, which increases the diffusion rate of rare-earth elements within a certain range. This work provides a feasible method to enhance coercivity and reduce the use of rare-earth resources by partial replacement of rare-earth elements with non-rare-earth elements in the diffusion source.

This paper abstracts the aircraft overhaul operation process into a directed network. Based on the analysis of the network structure, the calculation method of the operation time is given. Under the premise that the total resources and types of resources have been determined, an aircraft repair line resource optimization allocation model has been established to achieve the shortest single-machine repair time and find the optimal quantity ratio of various resources. According to the characteristics of the optimal allocation of aircraft repair line resources, the Binary Smart Wolf Pack Algorithm is used to solve the problems. Finally, the model and solution method are verified by a numerical example.

The existing transformer short-circuit test equipment and technology have several limitations. The purpose of short-circuit test is to simulate the test of high-voltage equipment under the short-circuit fault condition of the power system, usually, a large capacity test such as transformer burst short-circuit test, circuit breaker dynamic heat stability test, to verify the reliability and stability of related equipment under extreme working conditions. At present, the large capacity test generally uses methods of power grid dedicated line power supply and short-circuit testing alternator group. However, these two methods have difficulties in construction approval, high investment costs, complex site requirements, a large impact on the power grid, and low control accuracy. Theoretical studies on equivalent simulation verification method of short-circuit withstand capability test of distribution transformer demonstrated the feasibility of using modern power electronics and advanced energy storage technology to replace conventional power grid dedicated line power supply, short-circuit testing alternator and other short-circuit impact test equipment. It could complete the transformer short-circuit impact test specified by (IEC60076-5) with lower cost and higher efficiency, verify the short-circuit impact resistance of the transformer, and improve the test capacity.

Subsea pipelines are subject to complex loading environments, and fatigue damage is one of the main failure modes. Due to manufacturing or environmental factors, crack defects are inevitable in submarine pipelines. For subsea pipelines in service, it is of practical importance to predict the residual fatigue life. On the premise of the conservative estimation method, the MTS criterion is used to analyze the crack propagation mode of subsea pipelines. In the numerical prediction method, the crack stress intensity factor is solved by the finite element method combined with the 1/4 node displacement method, and then the fatigue life of the subsea pipeline is predicted by the da/dN method based on the Paris formula. The results show that when the crack size increment Δa is set reasonably, the predicted results of crack propagation life of subsea pipeline are close to the experiment results, which verifies the accuracy of the numerical prediction method. The choice of the crack size increment has a large impact on the life prediction and needs to be considered in terms of both calculation accuracy and time consumption. The results obtained provide a reference for the safety assessment of pipelines in service.

Path planning algorithms based on sampling have been widely studied and applied in recent years, among which the Informed-RRT* algorithm is a typically progressive optimization algorithm. To overcome the weakness of low optimization efficiency of the Informed-RRT* algorithm, an improved algorithm AIRRT* (Adaptive Informed-RRT*) is proposed, which can greatly improve optimization efficiency and improve the quality of optimized paths. According to the node distribution of the initial path, the appropriate node construction areas are dynamically selected first in the process of direct local sampling. Then collision detection and reconstruction are performed. Unlike the traditional algorithm, the AIRRT* algorithm determines the area to be reconstructed firstly, then performs direct local sampling in the reconstructed area, and finally reconstructs the path to improve the sampling efficiency. In addition, to reduce the searching difficulty of global path nodes, the invalid nodes are removed in reconstruction, which limits the growth of nodes in optimization. AIRRT* algorithm is compared with the common algorithms through simulation experiments, which proves that AIRRT* algorithm has obvious advantages in algorithm efficiency and path quality and has good applicability in varied scenarios.

In order to solve the problems in the practical application of the UR5 robot, improve the work efficiency and ensure the stability of the movement, the related kinematics analysis and trajectory planning of the UR5 robot is carried out, and the D-H parameter kinematics model is established to carry out forward and reverse motion. The transformation relationship of each link coordinate system in the forward kinematics and the rotation angle of each joint in the inverse kinematics are solved, and then MATLAB is used to perform related calculations to verify the feasibility of the algorithm. The robot arm performs interpolation to complete the trajectory planning between the beginning and end points passing through multiple intermediate nodes.

Laser additive manufacturing (AM) of lattice structures with light weight, excellent impact resistance, and energy absorption performance is receiving considerable attention in aerospace, transportation, and mechanical equipment application fields. In this study, we designed four gradient lattice structures (GLSs) using the topology optimization method, including the unidirectional GLS, the bi-directional increasing GLS, the bi-directional decreasing GLS and the none-GLS. All GLSs were manufactureed by laser powder bed fusion (LPBF). The uniaxial compression tests and finite element analysis were conducted to investigate the influence of gradient distribution features on deformation modes and energy absorption performance of GLSs. The results showed that, compared with the 45° shear fracture characteristic of the none-GLS, the unidirectional GLS, the bi-directional increasing GLS and the bi-directional decreasing GLS had the characteristics of the layer-by-layer fracture, showing considerably improved energy absorption capacity. The bi-directional increasing GLS showed a unique combination of shear fracture and layer-by-layer fracture, having the optimal energy absorption performance with energy absorption and specific energy absorption of 235.6 J and 9.5 J g−1 at 0.5 strain, respectively. Combined with the shape memory effect of NiTi alloy, multiple compression-heat recovery experiments were carried out to verify the shape memory function of LPBF-processed NiTi GLSs. These findings have potential value for the future design of GLSs and the realization of shape memory function of NiTi components through laser AM.

Using the two-way flow-heat and one-way thermo-solid coupling simulation analysis methods, the designed thin-film thermocouple is analyzed by finite element, and the flow field, temperature field, and structural field inside the sensor are obtained. The high-temperature redundant thin-film thermocouple working simulation test shows that: The response time of the designed thin-film thermocouple is less than 2 seconds, and the stress and deformation are within the required range under the operating temperature load and wind load.

Most of the traditional flow standard devices are fixed, with very large volumes. When the enterprise has the measurement demand, the client needs to remove all the flowmeters and send them to the location of the standard device, take them back after testing and reinstall them on the production line, resulting in low production efficiency. However, while pursuing the mobility of the device, the overall space, weight, and layout of the device are bound to be limited, thus affecting the stability of the water source and measurement accuracy. Therefore, this paper analyzes the characteristics of mobile devices, in the pursuit of lightweight at the same time design and building water source loop, branch, the overall electrical system, and write the host computer calibration software, and finally through the automatic adjustment of the solenoid valve with PID control scheme to adjust the flow, to improve the stability of water sources.

This paper presents a low-power high-quality CMOS image sensor (CIS) using 1.5 V 4T pinned photodiode (4T-PPD) and dual correlated double sampling (dual-CDS) column-parallel single-slope ADC. A five-finger shaped pixel layer is proposed to solve image lag caused by low-voltage 4T-PPD. Dual-CDS is used to reduce random noise and the nonuniformity between columns. Dual-mode counting method is proposed to improve circuit robustness. A prototype sensor was fabricated using a 0.11 µm CMOS process. Measurement results show that the lag of the five-finger shaped pixel is reduced by 80% compared with the conventional rectangular pixel, the chip power consumption is only 36 mW, the dynamic range is 67.3 dB, the random noise is only 1.55 e– rms, and the figure-of-merit is only 1.98 e–·nJ, thus realizing low-power and high-quality imaging.

The 74Se is one of 35 p-nuclei, and 82Se is a r-process only nucleus, and their (n, γ) cross sections are vital input parameters for nuclear astrophysics reaction network calculations. The neutron capture cross section in the resonance range of isotopes and even natural selenium samples has not been measured. Prompt γ-rays originating from neutron-induced capture events were detected by four C6D6 liquid scintillator detectors at the Back-n facility of China Spallation Neutron Source (CSNS). The pulse height weighting technique (PHWT) was used to analyze the data in the 1 eV to 100 keV region. The deduced neutron capture cross section was compared with ENDF/B-VIII.0, JEFF-3.2, and JENDL-4.0, and some differences were found. Resonance parameters were extracted by the R-matrix code SAMMY in the 1 eV–1 keV region. All the cross sections of natSe and resonance parameters are given in the datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00019.

Transient startup operating parameter has a serious influence on the stability of water-lubricated bearings. In this study, CFD method was used to predict the rotordynamic coefficients of water lubricated bearings under transient loads. The stiffness and damping coefficients versus transient time for water-lubricated bearings are given. The stiffness and damping coefficients versus different transient loads for water-lubricated bearings are also given. The results show that the stiffness and damping coefficients will increase rapidly in a very short time. With the increase of impact time, both of them come to a steady value. With the increase of impact load, the direct stiffness and the direct damping coefficients of water lubricated bearing will increase. The value of cross-coupling stiffness and the cross-coupling damping coefficients will decrease.

The dynamics of quadrotor UAV is described considering internal uncertainty and external disturbance. The control system of quadrotor UAV is divided into inner loop attitude control system and outer loop position control system, In order to solve the problem of underactuated character. Three virtual control variables are introduced to decouple the position dynamics. Three sliding mode disturbance observers (SMDOs) are designed to estimate the total disturbances in the position dynamics. Then three sliding mode controllers (SMCs) are designed to drive the trajectory tracking errors to zero asymptotically. The simulation example is carried out to test the effectiveness of SMDOs and SMCs. Simulation results validate that the designed SMDOs and SMCs provide both fast exact tracking capability and strong disturbance rejection capability for the quadrotor UAV.

Parameter selection is crucial to regularization-based image restoration methods. Generally speaking, a spatially fixed parameter for the regularization term does not perform well for both edge and smooth areas. A larger parameter for the regularization term reduces noise better in smooth areas but blurs edge regions, while a small parameter sharpens edge but causes residual noise. In this paper, an automated spatially adaptive regularization model, which combines the harmonic and total variation (TV) terms, is proposed for the image reconstruction from noisy and blurred observation. The proposed model detects the edges and then spatially adjusts the parameters of Tikhonov and TV regularization terms for each pixel according to the edge information. Accordingly, the edge information matrix will also be dynamically updated during the iterations. Computationally, the newly-established model is convex, which can be solved by the semi-proximal alternating direction method of multipliers with a linear convergence rate. Numerical simulation results demonstrate that the proposed model effectively preserves the image edges and eliminates the noise and blur at the same time. In comparison to state-of-the-art algorithms, it outperforms other methods in terms of peak signal to noise ratio, structural similarity index and visual quality.

To maintain sensitivity of the sensor, especially the infrared band sensor, liquid nitrogen is needed for cooling during the imaging process of airborne hyperspectrometer. However, traditional filling process requires a lot of manual intervention, which is not only time-consuming and labor-intensive, but also creates great potential safe hazard during aviation operations. In view of this, this paper designs an airborne hyperspectral automatic filling device for liquid nitrogen using time-delay electromagnetic switch, pressure sensing detector and electromechanical device, which achieves the purpose of automatic liquid nitrogen filling, increases operation efficiency of airborne hyperspectral equipment, reduces air stage operation steps, and guarantees personal safety of air operators, thus playing a good demonstration role in further standardizing and optimizing the technical process of air-borne hyperspectral remote sensing data.

We suggest an indirect approach for solving eigenproblems in quantum mechanics. Unlike the usual method, this method is not a technique for solving differential equations. There exists a duality among potentials in quantum mechanics. The first example is the Newton–Hooke duality revealed by Newton in Principia. Potentials that are dual to each other form a duality family consisting of infinite numbers of family members. If one potential in a duality family is solved, the solutions of all other potentials in the family can be obtained by duality transforms. Instead of directly solving the eigenequation of a given potential, we turn to solve one of its dual potentials which is easier to solve. The solution of the given potential can then be obtained from the solution of this dual potential by a duality transform. The approach is as follows: first to construct the duality family of the given potential, then to find a dual potential which is easier to solve in the family and solve it, and finally to obtain the solution of the given potential by the duality transform. In this paper, as examples, we solve exact solutions for general polynomial potentials.

Dielectric barrier discharges (DBDs) have been widely used in ozone synthesis, materials surface treatment, and plasma medicine for their advantages of uniform discharge and high plasma-chemical reactivity. To improve the reactivity of DBDs, in this work, the O2 is added into Ar nanosecond (ns) pulsed and AC DBDs. The uniformity and discharge characteristics of Ar ns pulsed and AC DBDs with different O2 contents are investigated with optical and electrical diagnosis methods. The DBD uniformity is quantitatively analyzed by gray value standard deviation method. The electrical parameters are extracted from voltage and current waveforms separation to characterize the discharge processes and calculate electron density n e. The optical emission spectroscopy is measured to show the plasma reactivity and calculate the trend of electron temperature T e with the ratio of two emission lines. It is found that the ns pulsed DBD has a much better uniformity than AC DBD for the fast rising and falling time. With the addition of O2, the uniformity of ns pulsed DBD gets worse for the space electric field distortion by O2 −, which promotes the filamentary formation. While, in AC DBD, the added O2 can reduce the intensity of filaments, which enhances the discharge uniformity. The ns pulsed DBD has a much higher instantaneous power and energy efficiency than AC DBD. The ratio of Ar emission intensities indicates that the T e drops quickly with the addition of O2 both ns pulsed and AC DBDs and the ns pulsed DBD has an obvious higher T e and n e than AC DBD. The results are helpful for the realization of the reactive and uniform low temperature plasma sources.