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The synaptic devices based on various electronic materials have been widely investigated to realize functions of artificial information processing with low power consumption. In this work, a novel CVD graphene field-effect transistor is fabricated with ionic liquid gate to study the synaptic behaviors based on the electrical-double-layer mechanism. It is found that the excitative current is enhanced with the pulse width, voltage amplitude and frequency. With different situations of the applied pulse voltage, the inhibitory and excitatory behaviors are successfully simulated, at the same time the short-term memory is also realized. The corresponding ions migration and charge density variation are analyzed in the different time segments. This work provides the guidance for the design of artificial synaptic electronics with ionic liquid gate for low-power computing application.

Electron cyclotron resonance is induced to enhance the discharging performance of a cusped field thruster, by feeding microwave into the channel. Due to a critical combination of ECR discharge and DC discharge, propellant utilization is significantly improved, with varying degrees of impact on other parameters. The DC mode, the ECR mode and the combined mode are achieved and analyzed respectively. A Faraday probe and a retarding potential analyzer are employed to diagnose the plume plasma, and approximate calculated thrust is given. In addition, high frequency electric field simulation is carried out to indicate the microwave feeding process in different mass flow rate conditions, making use of a Particle-In-Cell simulation result. The result shows that the ECR enhancement is particularly effective in low mass flow conditions, and the special plasma distribution in the cusped magnetic field leads to the propellant utilization trend in the combined mode.

The analysis of safety-critical systems designed by architectural languages such as AADL (Architecture Analysis and Design Language) is a challenging research topic. In such a context, formal methods become an advocated practice in software engineering for rigorous analysis. Moreover, they are applied on specific formalisms to be analyzed on dedicated tools. This paper studies the comprehensive formal specification for AADL language, in particular supporting major components of AADL and Behavior Annex. The presentation of this specification and modeling is the aim of this paper. This work is illustrated with a ARINC653 case study. As a study case, this work develops an AADL model from an ARINC653, specify a set of critical properties of the model and perform formal modeling in in Isabelle/HOL.

The trip on the 110kV transmission line was caused by the collapse of cement pole and disconnection of wire. A series of tests including macro check, dimensional measurement, mechanical property test and metallographic observation, have been carried out for the failure investigation. The experimental results showed that the failure of #43 pole was caused by combination of the rusting and breakage of transmission line under corrosive conditions and the unqualified hoops cannot bear the impact load and unbalanced tension of broken wires. At the same time, the corresponding supervision measures concerning about the design and purchase of materials used in Grid system and operation and maintenance inspection requirements were also put forward.

In the paper, the pressure and temperature response of the containment with free volume 1400m3 and 2000 m3 is analyzed based on the mass and energy release for postulated loss of coolant accident (LOCA). And the relation between containment free volume and containment pressure also is analyzed. The results of calculation have certain guiding significance for the determination of the pressurized water reactor (PWR) volume.

The forebody/inlet shape of the scramjet engine is significant to airplane performance. A multi-object optimization of hypersonic body-intake configuration is reported in the present work. The optimization system consists of geometry parameterization, mesh deformation, aerodynamic performance evaluation via computational fluid dynamics (CFD) and the top level driving optimization algorithm. In the present work, geometry parameterization is accomplished through B-Spline based free form deformation (FFD) method, volume mesh deformation is computed via inverse distance weight (IDW) method. Aerodynamic performance is evaluated with shear stress transportation model closed Reynolds averaged Navier-Stokes equations. At the top level, optimization is driven by the non-dominated sorting genetic algorithm II (NSGA-II) algorithm. Finally, the present optimization system is applied to a two dimensional hypersonic combined forebody-intake configuration. Numerical result shows that optimization gained improvement of 5% thrust, 9% pressure rise ratio and 7% total mass flow rate, which approved the effectiveness of the present optimization methodology.

Under extreme thermal environment, ablation process of thermal protection system is a key issue in atmospheric re-entry and hypersonic flight vehicles; it displays a strong coupling between ablation mass, velocity and heat transfer. This article presents a method for combining the ablating and melting process, building a right triangle carbon-carbon model for ablation mixed with octadecane phase change material to absorb the heat of combustion delaying the movement of burning interface. For the moving of boundary, it is treated by the modified Stefan model coupled with chemical reaction and thermal radiation at the front leading boundary. The governing equation of heat transfer considering the melting process of phase change material is given by referring the enthalpy method. The effect of volume ratio and aerodynamic heating on the ablation interface and net heat flux on the interface are investigated. Result shows that high volume ratio of the phase change material delays the movement of the interface, and decreases the net heat flux of the interface; on the other hand, high aerodynamic heat accelerates the movement of the interface and increases the interface net heat flux at a given time point. This study can give a rule on how the volume ratio of phase change material influence the ablative process quantitatively.

In this paper, the CoCrAlYTa-10%Al2O3 and Cr3C2-NiCr coatings were prepared by High-velocity oxygen-fuel (HVOF) spraying. The high-temperature wear test was carried out by ball-on-disk high temperature tribometer. The results showed that the CoCrAlYTa-10%Al2O3 coating exhibited lower micro-hardness and higher high-temperature wear resistance as compared with the Cr3C2-NiCr coating. At the end of the wear test, the friction coefficients of the coatings flattened out gradually, which illustrated that the coatings had not failed. With increasing of the loads, the wear rate of the CoCrAlYTa-10%Al2O3 coating first decreased and then increased as loads higher than 9 N. A similar trend was also observed in the Cr3C2-NiCr coating, while the difference was that the wear rate started to rise after the loads more than 6 N. As the loads were lower than 9 N, the wear mechanism of the CoCrAlYTa-10%Al2O3 coating was primarily abrasive wear, there were tribofilms formation on the worn track. Severe plastic deformation and micro-ploughing were appeared on the worn track surface under the load of 12 N. The wear mechanism was mainly abrasive wear, followed by adhesive wear. At 3 N, the worn surface of the Cr3C2-NiCr coating exhibited comparatively rough and some spalled pits. As increasing of the loads, spalled pits and grooves appeared on the surface of the worn track, the wear mechanism of Cr3C2-NiCr coating was mainly abrasive wear, followed by adhesive wear.

Theory of thermal fluctuations in two-band superconductors under an essentially homogeneous magnetic field is developed within the framework of the two-band Ginzburg–Landau theory. The fluctuating specific heat is calculated by using the optimized self-consistent perturbation approach and the results are applied to analyze the thermodynamic data of the iron-based superconductors Ba1−x K x Fe2As2 with x ~ 0.4, which have been suggested to have a two-band structure by recent experiments. We estimate the fluctuation strength in this material and find that the specific heat is described well with the Ginzburg number Gi = 410−4. The influence of interband coupling strength is investigated and the result of the two-band Gaussian approximation approach is compared.

In this paper, motivated by the driving mechanism of a putt-putt toy boat, we explore the feasibility to propel a microsubmarine using a thermally oscillatory approach, which only requires a simple design and does not involve any complicated propulsive systems. We investigate the design, fabrication, actuation and horizontal motions of the corresponding microsubmarines. Based on the understanding gained through preliminary tests on two manually fabricated putt-putt boats, we designed and fabricated the prototype of a microsubmarine. Similar to a putt-putt boat, the prototype also uses a thermally oscillatory process for propulsion. In a cyclic period of this process, due to the expansion and shrinkage of a vapor bubble inside the reservoir of the submarine, liquid is first ejected outside and then sucked into the reservoir. Due to the difference in liquid flow directions between ejection and suction stages, a thrust is produced to propel the submarine. At an applied voltage of 16 V and pulse frequency of 100 Hz, the submarine was found to have the highest speed of 1.8 mm s−1 and longest travel distance of 12.6 mm. The corresponding thrust was estimated to be 67.6 nN.