摘要：This paper presents and verifies a new idea for constructing an ultrasonic motor （USM）. The stator contains several vibrators fabricated by bonding piezoelectric ceramics （PZTs） to a metal base. When two alternating current （AC） voltages with a 90° phase difference are applied to the PZTs, longitudinal and bending modes are excited in the vibrator. The bending vibrations of the vibrators are stacked to form the torsional vibration of the stator, ultimately generating longitudinal-torsional composite vibration. Both vibrators and the stator are excited to the resonance state. A standing wave is formed by superposition of longitudinal and torsional modes. The proposed motor is an in-plane vibration motor because the vibrations of the stator are in the circumferential plane. The finite element method （FEM） is used to validate the feasibility of the proposed motor. The fabricated stator contains five vibrators. The tested resonance frequencies of longitudinal and torsional modes are 44.42 kHz and 43.83 kHz, respectively. The stall torque is 0.3 N＇m and no-load speed is 45 r/min. The highest efficiency is 30%. The applied driving voltage is 100 Vo.p （peak voltage） at 43.9 kHz. The designed motor is a parallel-actuated integral motor. It allows the vibrators to operate synchronously, and overcomes asynchronous issues that occur in traditional multi-vibrator motors.

摘要：The suppression of combustion instabilities using the extremum seeking algorithm(ESA) is analyzed.A function model of the pressure oscillation and the mean fuel–air ratio in the combustion chamber is derived and implies an extremum relation between the oscillation amplitude of the pressure and the mean fuel–air ***, the control system of combustion instabilities can be considered as an extremum seeking control system(ESCS). All traditional ESCSs employ a separate design method, which divides the design of the ESA from the controller design. It is thus difficult for traditional ESCSs to achieve optimal performance of the control system. To solve this problem, an integrated extremum seeking control method for ESCSs is proposed. Using this integrated control, the minimal oscillation amplitude of the pressure is realized by adaptively seeking the optimal mean fuel–air ratio. Hence, this design method can effectively suppress combustion instabilities in aeroengines. By comparing simulation results, the effectiveness of the proposed method is validated.

摘要：Both of planar and mesoporous architectures prevail for perovskite solar cells(PSCs).However,it is still an open question how the architecture affects the performance of *** inconsistent results in the references often create *** particular,the specific roles of mesoporous frameworks are yet to be well elaborated and require further *** this study,we carefully compared the properties of perovskite films and the device performances for both architectures to unravel the roles of mesoporous TiO2 framworks in CH3NH3PbI3 *** detailed characterizations of structural,microscopic,optical and electrical properties revealed that the presence of mesoporous TiO2 framework contributed to enlarged perovskite crystal sizes,enhanced light harvesting,efficient electron extration and suppressed charge *** a result,compared with the planar device,the mesoporous device yielded an improved power conversion efficiency of 18.18%,coupled with a reduced *** study reveals the benefits of mesoporous TiO2 framework in PSCs and provides the guidance for the design and optimization of architectures for high-performance devices.

摘要：Design and construction of the first prototype ionization chamber for CSNS and Proton Accelerator （PA） beam loss monitor （BLM） system is reported. The low leakage current （〈0.1 pA）, good plateau （≈800 V） and linearity range up to 200 Roentgen/h are obtained in the first prototype. All of these give us good experience for further improving the ionization chamber construction.

摘要：Based on the first ionization chamber （IC） prototype, the structure, working gas component and electrode material of the IC are improved. The test of the improved IC shows that the plateau length is about 2000 V, the plateau slope is less than 0.2%/100 V, the sensitivity is 19.6 pA/rad·h 1, the up-limitation of the linearity can be up to 3.6×105 rad/h, and the applied voltage can be operated to 3500 V. The test results show that the performance of the improved IC meets the requirements of the beam loss monitor.

摘要：The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)*** carbon-based and transition metal compound-based material solutions generally suffer from poor catalysis and adsorption,respectively,despite the performance gain in terms of the ***,we have enhanced polysulfide adsorptioncatalytic capability and protected the Li anode using a complementary bimetallic carbide electrocatalyst,Co3 Mo3 C,modified commercial *** this demonstration,the potentials of bimetal compounds,which have been well recognized in other environmental catalysis,are also extended to Li-S *** with this modified separator,a simple cathode(S/Super P composite)can deliver high sulfur utilization,high rate performance,and excellent cycle stability with a low capacity decay rate of^0.034%per cycle at 1 C up to1000 *** at a high S-loading of 8.0 mg cm^-2 with electrolyte/sulfur ratio=6 m L g^-1,the cathode still exhibits high areal capacity of^6.8 m A h cm^-*** experimental analysis and the first-principles calculations proved that the bimetallic carbide Co3 Mo3 C provides more binding sites for adsorbing polysulfides and catalyzing the multiphase conversion of sulfur/polysulfide/sulfide than monometallic carbide Mo2 ***,the modified separator can be reutilized with comparable electrochemical *** also showed other bimetallic carbides with similar catalytic effects on Li-S batteries and this material family has great promise indifferent energy electrocatalytic systems.