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Continuous breakthroughs of photoelectric conversion efficiency (PCE) in perovskite solar cells are achieved, but the inherent instability caused by residual tensile strain and interfacial defects remains a major obstacle to their application. In this study, a polydentate ligand‐regulated dual‐surface stress management strategy for perovskite (PVK) is introduced to eliminate tensile strain and interface defects via multidentate anchoring. 3‐amino‐5‐bromopicolinaldehyde (BD) is employed on the lower surface of PVK, while its −CO, −NH2, and pyridine functional groups facilitate the bridging of SnO2 with PVK, alleviating tensile stress and lowering interfacial energy barriers. For the upper surface, the bis−SO2, pyridine, and bis−CF3 functional groups of N‐(5‐Chloro‐2‐pyridyl) bis(trifluoromethanesulfonimide) (FC) are utilized to increase the ion migration energy barrier through anchoring, which effectively diminishes tensile stress and defects. Besides, −CF3 also constructs a hydrophobic barrier on the upper surface. Notably, tensile stress successfully transforms into compressive stress based on the dual‐surface stress regulation, significantly improving the framework stability of PVK. Consequently, the devices treated with BD and FC achieve an elevated open‐circuit voltage of 1.24 V and PCE of 24.70%. The modified device (unencapsulated) maintains 92% of initial PCE after 2000 h in the atmosphere and 91% after 500 h under 85% RH, showcasing enhanced stability. [ABSTRACT FROM AUTHOR]

The trap states at both the upper and bottom interfaces of perovskite layers significantly impact non‐radiative carrier recombination. The widely used solvent‐based passivation methods result in the disordered distribution of surface components, posing challenges for the commercial application of large‐area perovskite solar cells (PSCs). To address this issue, a novel NH3 gas‐assisted all‐inorganic dual‐interfaces passivation strategy is proposed. Through the gas treatment of the perovskite surface, NH3 molecules significantly enhanced the iodine vacancy formation energy (1.54 eV) and bonded with uncoordinated Pb2+ to achieve non‐destructive passivation. Meanwhile, the reduction of the film defect states is accompanied by a decrease in the work function, which promotes carrier transport between the interface. Further, a stable passivation layer is constructed to manage the bottom interfacial defects using inorganic potassium tripolyphosphate (PT), whose ─P═O group effectively mitigated the charged defects and lowered the carrier transport barriers and nucleation barriers of PVK, while the gradient distribution of K+ improved the crystalline quality of PVK film. Based on the dual‐interface synergistic effect, the optimal MA‐contained PSCs with an effective area of 0.1 cm2 achieved an efficiency of 24.51% and can maintain 90% of the initial value after aging (10−20% RH and 20 °C) for 2000 h. [ABSTRACT FROM AUTHOR]

Thermal management of power lithium-ion battery modules is very important to avoid thermal problems such as overheating and out of control, the study of thermal behavior of battery modules can provide guidance for the design and optimization of modules and thermal management. In this paper, a 3d thermal model of the power lithium-ion battery module is established based on STARCCM+ by using computational fluid dynamics (CFD) method, and a grid independence simulation test is used to determine the number of grids, the temperature distribution is analyzed under the condition of 1C charge current. The research results show that the internal temperature rises gradually with the charge going on, the temperature distribution of the cells is basically symmetrical. When the heat transfer coefficient is 5W/(m2⋅K) and the natural convective air inlet temperature is 300K, the module temperature uniformity is good. But because of the maximum temperature slightly higher than the temperature of thermal runaway, additional cooling methods need to be considered to cool the battery.

Trajectory tracking plays a notable role in unmanned surface vehicles (USV), especially for the emerging intelligent aquaculture, as the level of integration, high-efficiency, and low-labor-intensity of such USV is determined by trajectory tracking. Here, we report a generic trajectory tracking control system for a paddle boat by establishing a three-degree-of-freedom kinematics model, which could precisely characterize the relationship between velocities, forces and moments of the paddle boat. A Pixhawk 4 as the core controller of the hardware system could be integrated with the other hardware submodules and could complete the wireless data transmission, monitoring and remote control functions. Meanwhile, we establish a fuzzy rule table, consider the advantages of line-of-sight (LOS) guidance and fuzzy adaptive proportional-integral-differential (PID) algorithm, combine the two parts and apply them as the key algorithm in the trajectory tracking of the paddle boat. Demonstrations include trajectory tracking effect at different velocities, turning effect at left-turn moment, and trajectory tracking effect at different turning angles. The results show that the paddle boat is able to travel under the trajectory formed by following the planned waypoints within the error allowed, which is called effective trajectory tracking. And can offer an alternative pathway toward achieving effective trajectory tracking control in advanced intelligent aquaculture USV for smartly and wirelessly operated pond drug spraying. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate working performance for a four-stroke piston type compressed air engine (CAE) via experimental research. A conventional internal combustion engine(IC engine) is modified to a four-stroke CAE and a mathematical model is set up. Working performances are investigated by output torque, power, air consumption, exhaust pressure, exhaust temperature and cylinder pressure on a test bench. The CAE is installed on a vehicle for the road test. The experiment and analysis show several meaningful results. The increase of the supply pressure will result in the increase of the rotational speed, and it can effectively improve the output torque and power. However, it can lead to an increase in air consumption. The success of this application demonstrates compressed air cars are likely to be industrialized duo to their zero pollution and zero emissions.

Introducing excess PbI2 has proven to be an effective in situ passivation strategy for enhancing efficiency of perovskite solar cells (PSCs). Nevertheless, the photoinstability and hysteresis are still tough issues owing to the photolysis nature of PbI2. Moreover, the humidity‐related degradation of perovskite films is also a difficult territory to cover in such an in situ passivation strategy. Herein, a synergistic strategy is reported via initiatively inducing vertical graded PbI2 distribution (GPD) in the whole perovskite film and capping a cis‐Ru(H2dcbpy)(dnbpy)(NCS)2 (Z907) internal encapsulation (IE) layer on the surface to ameliorate the above issues. The GPD design can enhance luminescence, prolong carrier lifetimes, ascertaining the improvement of efficiency and elimination of photoinstability in the PSCs. Besides, the introduced IE layer not only can promote the moisture and thermal resistance, but also inhibit Pb leakage and ion migration in the PSCs. Through the synergetic regulations, the resultant PSCs exhibit an impressive open circuit voltage (VOC) of 1.253 V, fill factor of 81.25%, and power conversion efficiency (PCE) of 24.28%. Moreover, the PSCs maintain 91% of its initial PCE at relative humidity of 85% after 500 h aging and 94% under continuous heating at 85 °C after 750 h aging. [ABSTRACT FROM AUTHOR]

As it involves the lightest physical states excited from the vacuum by the vector quark current, near-threshold ρ0 photoproduction is considered a possible way to research the proton radius and the absolute value of the scattering lengths of the ρ0-proton interaction. In this study, under the assumption of a scalar form factor of dipole form, the value of the proton mass radius is calculated as (0.85 ± 0.06) fm by fitting the differential cross section of the γp → ρ0p reaction at near-threshold energy. For light vector meson photoproduction, because the exchange of a scalar quark-antiquark pair is not suppressed and should dominate the scalar gluon exchange, the radius we extract from ρ0 photoproduction is likely to represent the quark radius of the proton. This fact may explain why the value obtained in this study is very near the proton charge radius. Moreover, the absolute value of the ρ0-proton scattering length ∣ α ρ 0 p ∣ = (0.31 ± 0.06) fm is obtained for the first time within the vector meson dominance model. This result disobeys the rule that the absolute value of the vector meson and proton scattering length ∣ α V p ∣ increases with the meson’s mass, which can be attributed to treating the ρ0 meson as a point in the analysis. These results provide useful theoretical information for an in-depth understanding of proton structure and the proton-vector meson interaction. [ABSTRACT FROM AUTHOR]

Research on compressed air engine (CAE) is of great value under the background of energy conservation, emission reduction, and environmental protection in recent years. Compared with traditional internal combustion engine (ICE), four-stroke compressed air engine (F-s CAE) has no combustion and explosion process during operation, and the use and emission of working medium is clean air. Here, to deeply discuss the working performance of the F-s CAE, first, we expound a working principle of the F-s CAE. In addition, we analyze the control strategy of the electronic control unit (ECU) system and carry out a calibration test for the CAE. Meanwhile, we further conduct a feasibility analysis to verify its scientificity as the power of means of transport. In the test process, engine speed, supply pressure, port timing (intake advance angle and intake sustain angle) can directly affect the working performance. Results suggest that the overall effective power and single cylinder compressed air consumption increase with increase in the engine speed, while the average effective torque changes oppositely. Kinetic and dynamic characteristics are much better after supply pressure increased. The dynamic performance improves with the decrease in intake advance angle, but subsequently goes down when the intake advance angle decreases from 10°CA to −90°CA, and the intake advance angle as −70°CA is optimal. Overall, an intake sustain angle of 80°CA is more conducive to improving CAE dynamic performance compared to a relatively small intake sustain angle. The research results will be useful for further design and improvement of the F-s CAE. [ABSTRACT FROM AUTHOR]

The Cu2Ni0.05Zn0.95Sn(S,Se)4 (CNZTSSe) films were synthesized by sol-gel combined with selenidation treatment. To further enhance the crystal quality of the film, the selenidation conditions were optimized, and the effects of selenidation time on the properties of the CNZTSSe films and devices were systematically studied. The results show that the crystallinity of the films increased remarkably with the increase of selenidation time. Under the optimum selenidation time of 15 min, smooth and dense films were obtained. Through the analysis of EDS results, it is found that Se occupies more S positions with the increase of selenidation time, which decreases the band gap of the film from 1.14 eV to 1.0 eV. In addition, the formation of Zn-related defects is effectively suppressed by Ni doping to enhance the open circuit voltage (Voc) of the CNZTSSe solar cells. When the selenidation time is 15 min, the CNZTSSe film has the highest carrier concentration of 1.68 × 1016 cm−3, and the best efficiency of the device prepared based on the film as the absorption layer is 5.0%, and the Voc is 337 mV. [ABSTRACT FROM AUTHOR]

Cu2Ni0·05Zn0·95Sn(S,Se)4 (CNZTSSe) films were synthesized on Mo-coated glass substrates by the simple sol–gel means combined with the selenization process, and CNZTSSe-based solar cells were successfully prepared. The effects of selenization temperature on the performance and the photoelectric conversion efficiency (PCE) of the solar cells were systematically studied. The results show that the crystallinity of films increases as the selenization temperature raises based on nickel (Ni) doping. When the selenization temperature reached 540 °C, CNZTSSe films with a large grain size and a smooth surface can be obtained. The Se doping level gradually increased, and Se occupied the S position in the lattice as the selenization temperature was increased so that the optical band gap (Eg) of the CNZTSSe film could be adjusted in the range of 1.14 to 1.06 eV. In addition, the Ni doping can inhibit the deep level defect of SnZn and the defect cluster [2CuZn + SnZn]. It reduces the carrier recombination path. Finally, at the optimal selenization temperature of 540 °C, the open circuit voltage (Voc) of the prepared device reached 344 mV and the PCE reached 5.16%. [ABSTRACT FROM AUTHOR]

An effective battery thermal management system (BTMS) of power battery module for electric vehicles (EVs) plays a decisive role in battery life, cost, and safety in use. A BTMS method for a lithium-ion battery module, which is consisting of 12 prismatic cells, is proposed based on liquid cooling in the present work. Three circuitous channels embedded with a cooling plate are studied. In addition, the reliability and scientificity of the numerical model are verified by cooling performance tests. The simulation and test for this BTMS under a 3C discharging and charging rate were performed. Meanwhile, the performance evaluations of the battery module by considering different cooling conditions and battery arrangement are investigated numerically. With the help of the numerical model and test, the effects of flow area, mass flow rate, and cell gap on the battery temperature are examined and discussed. Simulation results illustrate that the larger flow area is experienced with a lower maximum temperature. BTMS with five channels design exhibits better heat dissipation behavior, and the maximum temperature and temperature difference under 80 g/s mass flow rate is about 45°C. Then, increases of maximum temperature and temperature difference are shown under lower mass flow rate, and the peak temperature at the lowest flow rate of 2 g/s is equal to 79.89°C, while it increases to 80 g/s, the peak temperature drops down to 47.43°C. Moreover, the lower the cell gap is, the worse the cooling performance is. Consequently, this study of this paper will provide a theoretical and an experimental basis for improving the battery module thermal behavior and BTMS strategy. [ABSTRACT FROM AUTHOR]

This study presents a theoretical model and an experimental investigation of a piston engine driven by compressed air. The compressed air engine (CAE) is proposed which is modified from a conventional internal combustion engine. The experiments in this study have used a test bench to examine the output torque and power performance and pressure variations of CAE at different port timing. The study has found that port timing has a direct influence on the working performances of CAE. Based on the theoretical analysis, the model of CAE developed for engine performance analysis and working process is described in this paper. In addition, good agreement of simulation results is obtained between the model and the test. The results show that, as intake advance angle increases, the cylinder pressure decreases during the expansion stroke stage and the exhaust stroke stage. An increase of cylinder pressure is shown at larger intake sustain angle. Moreover, one can find that compared with exhaust advance angle, the intake advance angle and the intake sustain angle have more influence on output torque and power. Consequently, this study of this paper will provide a theoretical and an experimental basis for further study on optimizing the design of CAE. [ABSTRACT FROM AUTHOR]

Trajectories of charged particles in two-dimensional axisymmetric magnetic fields bear obvious resemblance to epicyclods. The main focus of this study is the systematic assessment of the accuracy of the epicycloid approximation for particle trajectories under such conditions. We primarily discuss particle motion constrained to the equatorial plane of a magnetic dipole. It is shown that with well chosen epicycloid parameters, this approximation can remain accurate for conditions well outside the area of expected validity of the Guiding Center approach. Calculating the epicycloid parameters using exact results for particle motion in the equatorial plane of a magnetic dipole allows to retain the accuracy of this approximation to surprisingly high particle energies. We also show that this approach allows us to approximate the trajectory of a charged particle more accurately than its velocity. [ABSTRACT FROM AUTHOR]

A spiral bevel gear system supported on thrust bearings considering the coupled bending-torsional nonlinear vibration is proposed and an eight degrees of freedom (8DOF) lumped parameter dynamic model of the spiral bevel gear system combined with time-varying stiffness, static transmission error, gear backlash, and bearing clearances is investigated. The spiral bevel gear system is analyzed with the equations of motion and the dynamic response is solved using the Runge-Kutta method. The effects of mesh frequency, mesh damping coefficient, load coefficient, and gear backlash are revealed, which describe the true mesh characteristics of the spiral bevel gear system. The bifurcation characteristics as jump discontinuities, periodic windows, and chaos are obtained by studying time histories, phase plane portraits, Poincaré maps, Fourier spectra, and global bifurcation diagrams of the gear system. The results presented in this study provide some useful information for engineers in designing and controlling such gear systems. [ABSTRACT FROM AUTHOR]

In this study, we prepared Na-doped Cu2ZnSn(S,Se)4 [noted as (Na0.1Cu0.9)2ZnSn(S,Se)4] films on the Mo substrate using a simple and cheap sol–gel method together with the post-annealing technique. The effects of selenization temperature on the properties of Na-doped Cu2ZnSn(S,Se)4 were surveyed. The results indicated that some sulfur atoms in the films were substituted by selenium atoms by increasing the selenization temperature, and all films selenized at different temperatures had a kesterite structure. As the selenization temperature increased from 520 to 560 °C, the band gaps of the film can be tuned from 1.03 to 1 eV. The film with better morphology and opto-electrical properties can be obtained at an intermediate selenization temperature range (e.g., 540 °C), which had the lowest resistivity of 47.7 Ω cm, Hall mobility of 4.63 × 10−1 cm2/Vs, and carrier concentration of 2.93 × 1017 cm−3. Finally, the best power conversion efficiency (PCE) of 4.82% was achieved with an open circuit voltage (Voc) of 338 mV, a short circuit current density (Jsc) of 27.16 mA/cm2 and a fill factor (FF) of 52.59% when the selenization temperature was 540 °C. [ABSTRACT FROM AUTHOR]

In this work, the Cu2MnxZn1−xSn(S,Se)4 (0 ≤ x ≤ 1) (CMZTSSe) alloy films were fabricated by a sol-gel method. Meanwhile, the effects of Mn substitution on the structural, morphological, electrical, optical, and device performance were studied systematically. The clear phase transformation from Cu2ZnSn(S,Se)4 (CZTSSe) with kesterite structure to Cu2MnSn(S,Se)4 (CMTSSe) with stannite structure was observed as x = 0.4. The scanning electron microscope (SEM) results show that the Mn can facilitate the grain growth of CMZTSSe alloy films. Since the x was 0.1, the uniform, compact, and smooth film was obtained. The results show that the band gap of the CMZTSSe film with a kesterite structure was incessantly increased in a scope of 1.024–1.054 eV with the increase of x from 0 to 0.3, and the band gap of the CMZTSSe film with stannite structure was incessantly decreased in a scope of 1.047–1.013 eV with the increase of x from 0.4 to 1. Meanwhile, compared to the power conversion efficiency (PCE) of pure CZTSSe device, the PCE of CMZTSSe (x = 0.1) device is improved from 3.61% to 4.90%, and about a maximum enhanced the open-circuit voltage (VOC) of 30 mV is achieved. The improvement is concerned with the enhancement of the grain size and decrease of the Cu instead of Zn (CuZn) anti-site defects. Therefore, it is believed that the adjunction of a small amount of Mn may be an appropriate approach to improve the PCE of CZTSSe solar cells. [ABSTRACT FROM AUTHOR]

Cation substitution is a promising approach to reduce the antisite defects and further improve the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) cells. In this paper, silver (Ag) has been introduced into Cu2ZnSn(S,Se)4 (CZTSSe) thin film to replace Cu partially and form (Cu1-xAgx)2ZnSn(S,Se)4 (0 ≤ x ≤ 1) (CAZTSSe) alloy films by combination of solution method and a rapid annealing technique. The fundamental properties of the mixed Ag-Cu kesterite compound are systematically reported as a function of the Ag/(Ag+Cu) ratio. The results show that band gap of kesterite CAZTSSe is incessantly increased by adjusting the Ag doping content, indicating that the CAZTSSe alloy film is a potentially applicable bandgap grading absorption layers material to obtain higher CZTSSe device. Furthermore, CAZTSSe alloy films with better electrical performance were also obtained by adjusting the Ag content during film fabrication. Finally, we also observed an increment in open circuit voltage (Voc) by 160 mV and an accompanying rise in device efficiency from 4.24 to 5.95%. The improvement is correlated to the improved grain size and decreased antisite defects of Cu instead of Zn site (CuZn) in the lattice. The Voc enhancement evidences that the solution method is facile and viable to achieve proper cation substitution toward higher efficiency kesterite solar cells. In addition, the CAZTSSe cell also displays better charge collection performance because of the higher fill factor (FF) and power conversion efficiency (PCE). Therefore, it can be concluded that the doping of Ag is a potentially appropriate method to reduce the Cuzn antisite defects of CZTSSe and improve efficiency of CZTSSe device. [ABSTRACT FROM AUTHOR]