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The chemical composition and fracture toughness of thermal barrier coatings (TBCs) before and after heat treatment were characterized, and the cracks around the interface between the coating and the substrate could be successfully eliminated and meanwhile the porosity of the coatings tended to reduce. The XRD analysis revealed the coatings were composed of non-transformable tetragonal t’ phase of ZrO2 and γ $\gamma $-(Ni, Cr) with minor Ni3Al (γ′ $\gamma ^' $) precipitates. Additionally, the relationship between the heat treatment and wear resistance was systematically studied. The results indicated that both the hardness and fracture toughness increased after quenching process. The oxidation wear became more prominent after heat treatment, which probably resulted from the better bonding strength of coatings. Dense and homogeneous microstructure introduced by vacuum oil-quenching improved stabilization of the weight gain during thermal cycle test.

The miniaturization of the scrubber used in vessel flue gas desulphurization is a critical issue. In this study, the structure optimization of the vessel desulphurization scrubber based on CFD (computational fluid dynamics) and the SVM‐GA (support vector machine and genetic algorithm) is performed and a miniaturized scrubber design with the same desulphurization efficiency as large scrubbers is obtained. First, the seawater SO2 absorption process in a vessel desulphurization scrubber is investigated using the CFD‐DPM method, and the effects of the operating and structural parameters on the desulphurization efficiency η are discussed in detail. Results show that η is positively correlated to the absorption area height, H2, and the spray level number, N, and η first increases and then decreases with an increase in the scrubber diameter, D1, as well as the inlet flue angle, θ. Then, a prediction model of η considering D1, H2, θ, and N is established and validated using the SVM with the simulation data. Finally, D1, H2, θ, and N are optimized using the GA method based on the SVM model. The results show that the volume of the absorption area, Vab, can be reduced by 30 % while maintaining the same η through the use of this optimization method. [ABSTRACT FROM AUTHOR]

This paper clearly demonstrates the structure of Experimental Advanced Superconducting Tokamak (EAST) power supply system and analyzes principles of the finite-state machine (FSM) elaborately. Depending on the characteristics of EAST power supply system and the requirements of it, this paper chooses the real-time Linux as system platform and experimental physics and industrial control system (EPICS) as development tool to design a control system of the EAST poloidal field power system supply. This paper utilizes a temporal logic control based on the FSM in order to regulate the operation process of real-time sequence logic control of 12 sets of power controllers. This design is evaluated and tested, and it completely meets the real-time requirement of the poloidal field power supply (PFPS) control system. Several experiments have proved that this design definitely meets the real-time sequence logic control requirement of the PFPS control system in the complex situations under magnetic fields. [ABSTRACT FROM AUTHOR]

This paper clearly demonstrates the architecture of time synchronization network of experimental advanced superconducting tokamak (EAST) poloidal field (PF) power supply control system and analyzes characteristics of the IEEE 1588 in detail at the same time. IEEE 1588 has unique advantages for this paper to utilize as protocol in order to improve the accuracy of the time synchronization network (TSN). Consequently, we design a time synchronization system based on PCI eXtensions for Instrumentation-6683H. This paper utilizes one master node to synchronize all slave nodes on the time network in each second. The result shows that the synchronization accuracy can be achieved within 50 ns. According to results of experiments, this system can perfectly meet the requirements of EAST PF power supply control system. [ABSTRACT FROM AUTHOR]

The increasingly strict emission regulations in combustion engines are raising high requirements for the engine valve train system. In this paper, a novel multifunctional wear apparatus is designed to study the performance of engine valve train components. The apparatus employs a mechanical loading system, which consists of a special eccentric wheel and disc springs that apply the combustion loads, and the contact configurations and loading conditions of valve train components are simulated. It has three test functions for different components through specifically designed fixtures. The first function aims to evaluate the interaction between the valve seating face and the seat insert at high temperatures and loads. The second function is used to study the friction and wear properties of the valve stem and the valve guide. The third function is designed to evaluate the performance of the valve seals. At last, a verification test was carried out by the proposed experimental method. A pair of new exhaust valve and seat insert is tested for the performance evaluation of the first function. The wear mechanisms acting on the pairs interface are shown to be a combination of oxidative wear, adhesive wear, as well as fatigue flaking. [ABSTRACT FROM AUTHOR]

Passivation layer with linearly graded bandgap (LGB) was proposed to improve the performance of amorphous/crystalline silicon heterojunction (SHJ) solar cell by eliminating the large abrupt energy band uncontinuity at the a-Si:H/c-Si interface. Theoretical investigation on the a-Si:H(p)/the LGB passivation layer(i)/c-Si(n)/a-Si:H(i)/a-Si:H(n+) solar cell via AFORS-HET simulation show that such LGB passivation layer could improve the solar cell efficiency ( η) by enhancing the fill factor (FF) greatly, especially when the a-Si:H(p) emitter was not efficiently doped and the passivation layer was relatively thick. But gap defects in the LGB passivation layer could make the improvement discounted due to the open-circuit voltage ( VOC) decrease induced by recombination. To overcome this, it was quite effective to keep the gap defects away from the middle of the bandgap by widening the minimum bandgap of the LGB passivation layer to be a little larger than that of the c-Si base. The underlying mechanisms were analysed in detail. How to achieve the LGB passivation layer experimentally was also discussed. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Hydrogenated amorphous silicon germanium (a-SiGe:H) thin films were prepared by a 13.56-MHz plasma-enhanced chemical vapor deposition (PECVD) method. The optical, optoelectronic, and microstructure properties of the a-SiGe:H thin films prepared with different plasma powers were investigated systematically by transmission, photo/dark conductivity, Raman, and Fourier transform infrared (FTIR) spectroscopy measurements. It was found that when the deposition pressure was high and the hydrogen (H2) dilution ratio ([H2]/([SiH4] + [GeH4])) was low, an appropriate high plasma power could enlarge the optical bandgap ( Eg) by reducing the Ge content in the thin film, enhance the film photosensitivity by improving the film microstructure, and increase the film growth rate. As a demonstration, excellent a-SiGe:H thin film with Eg of 1.5 eV, the photosensitivity of above 104 and a growth rate of 6.6 Å s−1 was successfully fabricated for the solar-cell application with a plasma power density of 400 mW cm−2, a deposition pressure of 3 Torr, and a H2 dilution ratio equal to 3 at 220 °C. The underlying mechanism was further analyzed. [ABSTRACT FROM AUTHOR]