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Ultrasonic Vibration Assisted Cutting of Nomex Honeycomb Core Materials
Dao‑Hui Xiang,Bang‑Fu Wu,Yun‑Long Yao,Bo Zhao,Jin‑Yuan Tang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.1
Nomex honeycomb core materials have been widely used in the aviation industry due to their special structure and performance. Conventional high-speed machining have resulted in the poor machinability of the honeycomb core so that the ultrasonic machining technology was applied. The kinematic characteristics in the ultrasonic vibration assisted cutting process were analyzed according to the movement of the sharp tool. Based on slide effect, a cutting force model was proposed to study the relationship between cutting parameters and cutting force. Ultrasonic vibration assisted cutting and ordinary cutting tests of Nomex honeycomb core material were conducted by considering feed rate, the inclined angle and the deflected angle. Besides, the effects of cutting parameters on machined surface quality of honeycomb core wall were studied. The test results show that slide effect caused by ultrasonic vibrations can reduce cutting resistance compared with ordinary cutting. The developed cutting force model can be applied to evaluated the cutting force in the ultrasonic vibration assisted cutting of Nomex honeycomb core material. The inclined angle has a great influence on the cutting force during ultrasonic vibration assisted cutting. High-speed reciprocating sliding action can effectively cut aramid fibers so that burrs and tearing defects of the incision have been greatly improved under condition of ultrasonic vibration assisted cutting.
Fixed‑time non‑singular terminal sliding mode control for PMSM drive systems
Huixiang Liu,Keqi Mei,Lu Liu,Yafei Chang,Shihong Ding,Hanzhang Zhang,Jun Wang 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2
To further improve the response speed and anti-interference capability of permanent magnet synchronous motors (PMSMs), many advanced control algorithms have been developed. Among the various advanced controls, the fixed-time terminal sliding mode control is one of the effective methods. However, there are still some problems, e.g., too many parameters imposed on the control design in the existing results. In this paper, a fixed-time non-singular terminal sliding mode control (FTNTSMC) method is proposed for the speed loop of a PMSM drive system. First, to improve the closed-loop performance of the PMSM drive system, the relationship between the reference q-axis current and the speed of the PMSM is described in a second-order model. Next, a sliding mode surface with variable exponential coefficients is selected, and the expression of the controller is given. Then, the stability of the PMSM drive system is demonstrated by using Lyapunov functions. Using this method, the fixed-time convergence of the PMSM drive system can be realized and the occurrence of singularity phenomena can be avoided in a simpler and easier method. Finally, the effectiveness of the proposed method is verified by simulation and experimental results.
Huixiang Wu,CHANGJUN HOU,Huanbao Fa,Liang Dong,Yi Ma,Mei Yang,Caihong Shen,Jun Zhou,DANQUN HUO 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.7
Cartap is among the most popular pesticides that are widely used to boost food production, however, its residues pose a great threat to human health and the environment. We presented simple and effective colorimetric sensor based on aggregation of gold nanoparticles (AuNPs) with appropriate diameter and fluorescent sensor via inner filter effect (IFE) of AuNPs on cadmium telluride quantum dots (CdTe QDs), respectively. Firstly, effect of diameter of AuNPs was investigated and the results indicated that AuNPs with diameter of 13 nm (AuNPs13nm) showed better sensitivity toward cartap. Thus, AuNPs13nm was chosen for colorimetric and fluorescent cartap assay. On one hand, mercaptoacetic acid (MA) was functionalized on AuNPs13nm for the improvement of anti-disturbance ability for discrimination study. A decent linear relationship for cartap was obtained in the range from 1 µM to 50 µM with detection limit of 1.32 µM for colorimetric readout; on the other hand, fluorescent sensor based on AuNPs13nm displayed excellent linear relationship with cartap concentration varying from 20 nM to 100 nM with low detection limit of 4.02 nM. And the above-mentioned sensor showed acceptable anti-disturbance ability for cartap discrimination. These results demonstrated that the sensor as-developed would be a great potential candidate for cartap detection in real application.
Photoelectrocatalytic Degradation of Phenol Using a TiO₂/Ni Thin-film Electrode
Xiaoli, Yan,Huixiang, Shi,Dahui, Wang 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4
As a new type of photoelectrode, TiO₂/Ni thin-film electrode was prepared by dip-coating technique. The structural and surface morphology of electrode was examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). Effects of initial phenol concentration, pH value, number of film layers, voltage of electrical bias applied, variation of inorganic salt type and types of dissolved gas on the photoelectrocatalytic (PEC) degradation of phenol using ultraviolet (UV) illuminated TiO₂/Ni thin-film electrode were investigated. The mechanism of PEC degradation of phenol was also studied by analyzing reaction intermediates.
Peng Wan,Huixiang Yu,Feng Li,Pengfei Gao,Lei Zhang,Zhengzhi Zhao 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10
The hot deformation behavior of low-density high-strength Fe–Mn–Al–C alloy steel at T = 900-1150 °C and ̇ = 0.01-10 s−1was studied by the Gleeble-3500 thermo-mechanical simulator. The rheological stress curve characteristics of the steel wereanalyzed through experimental data, and a physical constitutive model considering strain coupling was established. At thesame time, the finite element software DEFORM was used to calculate the critical damage value of the steel, and the influenceof T and ̇ on the maximum damage value was considered. By introducing the dimensionless parameter Zener–Hollomon, thecritical damage model was established. Finally, the workability of the steel was evaluated by using the intuitive processingmap technology. The results indicated that Fe–Mn–Al–C alloy steel is a positive strain rate-sensitive and a negative temperature-sensitive material, and the constitutive model considering physical parameters can well predict the rheological stress ofthe steel during hot deformation (R = 0.997). The critical damage factor of Fe–Mn–Al–C alloy steel varies with the changeof T and ̇ , and the range is 0.359-0.535. At the same time, the critical damage factor is more sensitive to ̇ . At a constantT, the damage factor decreases with the increase of ̇ . Based on the Prasad instability criterion, the dynamic material modelprocessing map and the microstructure verification after thermal compression, the rheological instability characteristics ofthe steel are mainly mechanical instability and local plastic flow, and the stable deformation area is mainly characterized bydynamic recrystallization. The optimal hot working process window of the steel is 975-1050 °C/0.01-0.032 s−1.