Crosslinked Proton Exchange Membranes with a Wider Working Temperature Based on Phosphonic Acid Functionalized Siloxane and PPO

Zhihui Wu,Chunhui Shen,Shanjun Gao,Xi Zhu,Mingliang Zhang,Ao Ding 한국고분자학회 2021 Macromolecular Research Vol.29 No.3

A series of proton exchange membranes were prepared by incorporating phosphonic functionalized siloxane into sulfonic poly(2,6-dimethyl-1,4-phenyleneoxide) (SPPO) and imidazole functionalized poly(2,6-dimethyl-1,4-phenyleneoxide) grafted with siloxane (IPPO-Si). Phosphonic acid functionalized siloxane was synthesized from amino trimethyl phosphonic acid (ATMP) and (3-aminopropyl)triethoxysilane (APTES). FTIR results showed that 1-methylimidazole and APTES were successfully grafted onto polyphenylene oxide, and APTES successfully formed Si-O-Si crosslinked networks through hydrolytic crosslinking. The membranes were thermally stable up to 220 °C and exhibited excellent oxidative stability and mechanical performance. We also measured the proton conductivity of the membranes. The results showed that the proton conductivities of the composite membranes increased with the increasing of SPPO content at different degrees under high (100 °C-160 °C) and low (25 °C-80 °C) temperature conditions. Furthermore, the IPPO-SI-P/SPPO-30 has the best conductivity, reaching to 0.1131 S cm-1 at 80 °C, 100%RH and 0.1049 S cm-1 at 160 °C, 5%RH, respectively. Therefore, this novel membrane acts as a potential candidate for proton exchange membranes with a wider applicable temperature (25 °C-160 °C).

Dissipative Fault Detection for Nonlinear Markov Jump Systems With Cyber Attacks and Hidden Mode Information Under Round-robin Protocol

Zhihui Wu,Siteng Ma,Dongyan Chen,Xue Zhao,Cai Chen 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.11

This paper addresses the problem of dissipative fault detection (FD) for nonlinear Markov jump systems (MJSs) with cyber attacks and hidden modal information, in which the round-robin (R-R) protocol is introduced to save network bandwidth. Two Bernoulli random variables are used to characterize the measurement affected by potential cyber attacks. The hidden Markov model (HMM) is employed to handle the phenomenon of hidden mode information. Subsequently, the sufficient conditions are derived based on the Lyapunov stability theory to ensure that the FD system is stochastically stable and stochastically strictly (Q1, Q2, Q3)-γ dissipative. The desired FD filter matrices are obtained by solving linear matrix inequalities (LMIs). Finally, a simulation is provided to verify the feasibility and effectiveness of the designed FD scheme.

Quantized Consensus Control for Multi-UAVs based on Prescribed Performance

Zhihui Du,Jingping Shi,Zhonghua Wu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1

A distributed adaptive control approach based on a prescribed performance is proposed for multiple unmanned aerial vehicles (multi-UAVs) with disturbances and input quantization. The tracking error is converted into the consensus error by relying on the communication topology so that the distributed controller can be implemented. The radial basic function (RBF) neural network with composite learning is used to estimate the unknown nonlinear functions, and adaptive compensation terms are applied to compensate for the errors caused by filters and disturbances. A hysteretic quantizer is introduced to process the control input signal to relax the channel burden, and an estimator is implemented to solve the problem where the quantizer parameters are unknown. An improved Barrier Lyapunov function (BLF) is developed to ensure that the consensus error satisfies the prescribed performance requirements. Stability analysis proves that the tracking error and all signals in the closed-loop systems are bounded. Finally, all follower UAVs can track the virtual leader and maintain the given formation. A numerical simulation is provided to validate the effectiveness of the proposed control approach.

Ginsenoside Rg3 Inhibition of Thyroid Cancer Metastasis Is Associated with Alternation of Actin Skeleton

Wenshuang Wu,Qian Zhou,Wanjun Zhao,Yanping Gong,Anping Su,Feng Liu,Yang Liu,Zhihui Li,Jingqiang Zhu 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.9

Ginsenoside Rg3, a bioactive constituent from Panax ginseng, is a worldwide well-known traditional Chinese medicine used as a tonic. It also has good antitumor activity by inhibiting tumors metastasis. Tumor metastasis is a high risk in thyroid cancer. However, the effect and molecular mechanism underlying the antimetastatic activity of Rg3 in thyroid cancer have not been reported. In our study, we found that Rg3 inhibited the growth of thyroid cancer in vitro and in vivo and significantly inhibited metastasis of thyroid cancer. Rg3 apparently inhibited the migration and invasion in four papillary thyroid cancer (PTC) cells (TPC-1, BCPAP, C643, and Ocut-2c cells) and pulmonary metastasis in lung metastasis model of C643 cells in nude mice. We further found that a possible mechanism of Rg3 inhibiting thyroid cancer cells metastasis was associated with inhibiting cells actin skeleton function. Rg3 inhibited lamellipodia formation and induced microspike formation by inhibiting Rho GTPase in thyroid cancer cells. Rg3 decreased the levels of Rac-1 and Cdc42 proteins. In addition, Rg3 decreased the expression levels of matrix metalloproteinase-2 (MMP-2) and MMP-9 proteins in four thyroid cancer cells. The results that Rg3 remarkably inhibited the expression of vascular endothelial growth factor-C (VEGF-C) protein in PTC cells and VEGF-A protein in anaplastic thyroid cancer (ATC) cells and decreased the staining of CD31 in PTC and ATC tumors hinted that Rg3 might inhibit the lymph node metastasis in PTC and angiogenesis in ATC. These studies suggested that Rg3 might be a useful agent for the treatment of metastatic thyroid cancers.

Pervaporation performance of BTESE/TEOS-derived organosilica membrane and its stability in isopropanol aqueous solutions

Hongdan Wu,Xiaodi Liu,Xiaoyu Yang,Chuanzhi Hu,Zhihui Zhou 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.1

Organosilica membranes derived from bis(triethoxysilyl)ethane (BTESE) and tetraethyl orthosilicate (TEOS) were prepared by sol-gel method on porous α-Al2O3 supports and applied in pervaporation dehydration of isopropanol (IPA) aqueous solutions. The permeation characteristics of membranes in IPA/water mixture were evaluated for preparation conditions and stability, including long-term stability, acid resistance, and feed concentration. It was observed that the water contact angle of BTESE/TEOS-derived organosilica membrane decreased from (77.74±0.47)° to (36.67±1.05)° as the content of TEOS increased, which proved that the surface property of the membrane could be changed by the part of hydrocarbon units after hydrolysis condensation reaction. As the molar ratio of BTESE to TEOS was 1 : 2, the organosilica membrane showed high pervaporation performance for 90 wt% isopropanol aqueous solutions at 75 °C, with a water permeation flux of 10.580 kg·m−2·h−1 and separation factor of 1170. Stability experiments of long-term operation and acid environment in isopropanol aqueous solutions showed slight changes in flux and separation factor, proving that organosilica membranes had better stability. An increase in IPA concentration from 60 wt% to 90 wt% decreased both water flux and water content on the permeate side, suggesting that the effective pore sizes for permeation could be reduced by adsorption of IPA molecules, whereas the membrane remained high permeance in isopropanol aqueous solutions with high water content. The separation mechanism of pervaporation dehydration of isopropanol aqueous solutions by BTESE/TEOS-derived membrane was mainly attributed to the molecular sieve separation effect. The results showed that the BTESE/TEOS-derived organosilica membranes had an application prospect in the dehydration of aqueous-organic mixtures.

Wind Power Forecasting Based on Ensemble Empirical Mode Decomposition with Generalized Regression Neural Network Based on Cross-validated Method

Huanhuan Cai,Zhihui Wu,Chao Huang,Daizheng Huang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.5

The growth of wind power connected to the power grid has increased the importance of accurate wind power prediction that exhibits non-linearity and non-stationarity. The goal of this study is to forecast wind power by using the generalized regression neural network (GRNN) coupled with ensemble empirical mode decomposition (EEMD) and assessment of prediction accuracy. EEMD technologies are used to perform decomposition, and each intrinsic mode function is predicted and forecasted by using a GRNN based on cross-validated parameters. The forecasting results of the sub-series are superimposed as the results of wind power prediction. Results show that the proposed method has high prediction accuracy and is highly effective in forecasting wind power.

Dynamic Economic Dispatch for Microgrid Based on the Chance-Constrained Programming

Daizheng Huang,Lingling Xie,Zhihui Wu 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

The power of controlled generators in microgrids randomly fluctuate because of the stochastic volatility of the outputs of photovoltaic systems and wind turbines as well as the load demands. To address and dispatch these stochastic factors for daily operations, a dynamic economic dispatch model with the goal of minimizing the generation cost is established via chance-constrained programming. A Monte Carlo simulation combined with particle swarm optimization algorithm is employed to optimize the model. The simulation results show that both the objective function and constraint condition have been tightened and that the operation costs have increased. A higher stability of the system corresponds to the higher operation costs of controlled generators. These operation costs also increase along with the confidence levels for the objective function and constraints.

Beam Shaping and Speckle Reduction in Laser Projection Display Systems Using a Vibrating Diffractive Optical Element

Chuanyang Liang,Wei Zhang,Zhihui Wu,Dawei Rui,Yongxin Sui,Huaijiang Yang 한국광학회 2017 Current Optics and Photonics Vol.1 No.1

The laser has been regarded as the potential illumination source for the next generation of projectors. However, currently the major issues in applying the laser as an illumination source for projectors are beamshaping and laser speckle. We present a compact solution for both issues by using a vibrating diffractiveoptical element (DOE). The DOE is designed and fabricated, and it successfully transforms the circularGaussian laser beam to a low speckle contrast uniform rectangular pattern. Under a vibration frequencyof 150 Hz and amplitude of 200 μm, the speckle contrast value is reduced from 67.67% to 13.78%, andthe ANSI uniformity is improved from 24.36% to 85.54%. The experimental results demonstrate thefeasibility and potential of the proposed scheme, and the proposed method is a feasible approach to theminiaturization of laser projection display illumination systems.

Beam Shaping and Speckle Reduction in Laser Projection Display Systems Using a Vibrating Diffractive Optical Element

Liang, Chuanyang,Zhang, Wei,Wu, Zhihui,Rui, Dawei,Sui, Yongxin,Yang, Huaijiang Optical Society of Korea 2017 Current Optics and Photonics Vol.1 No.1

The laser has been regarded as the potential illumination source for the next generation of projectors. However, currently the major issues in applying the laser as an illumination source for projectors are beam shaping and laser speckle. We present a compact solution for both issues by using a vibrating diffractive optical element (DOE). The DOE is designed and fabricated, and it successfully transforms the circular Gaussian laser beam to a low speckle contrast uniform rectangular pattern. Under a vibration frequency of 150 Hz and amplitude of $200{\mu}m$, the speckle contrast value is reduced from 67.67% to 13.78%, and the ANSI uniformity is improved from 24.36% to 85.54%. The experimental results demonstrate the feasibility and potential of the proposed scheme, and the proposed method is a feasible approach to the miniaturization of laser projection display illumination systems.

Dynamic Economic Dispatch for Microgrid Based on the Chance-Constrained Programming

Huang, Daizheng,Xie, Lingling,Wu, Zhihui The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

The power of controlled generators in microgrids randomly fluctuate because of the stochastic volatility of the outputs of photovoltaic systems and wind turbines as well as the load demands. To address and dispatch these stochastic factors for daily operations, a dynamic economic dispatch model with the goal of minimizing the generation cost is established via chance-constrained programming. A Monte Carlo simulation combined with particle swarm optimization algorithm is employed to optimize the model. The simulation results show that both the objective function and constraint condition have been tightened and that the operation costs have increased. A higher stability of the system corresponds to the higher operation costs of controlled generators. These operation costs also increase along with the confidence levels for the objective function and constraints.