The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer treatment.Herein,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to ...The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer treatment.Herein,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to treat breast cancer via accurate tumor elimination,on-demand adipose tissue regeneration and effective infection inhibition.The hydrogel consisted of thiol groups ended polyethylene glycol(SH-PEG-SH)and doxorubicin encapsulated mesoporous silica nanocarriers(DOX@MSNs)double crosslinked hyaluronic acid(HA)after loading of antibacterial peptides(AP)and adipose-derived stem cells(ADSCs).A pH-cleavable unsaturated amide bond was pre-introduced between MSNs and HA frame to perform the tumor-specific acidic environment dependent DOX@MSNs release,meanwhile an esterase degradable glyceryl dimethacrylate cap was grafted on MSNs,which contributed to the selective chemotherapy in tumor cells with over-expressed esterase.The bond cleavage between MSNs and HA would also cause the swelling of the hydrogel,which not only provide sufficient space for the growth of ADSCs,but allows the hydrogel to fully fill the irregular defects generated by surgery and residual tumor atrophy,resulting in the on-demand regeneration of adipose tissue.Moreover,the sustained release of AP could be simultaneously triggered along with the size change of hydrogel,which further avoided bacterial infection to promote tissue regeneration.展开更多
Microbial fuel cells(MFCs)incorporating air-breathing cathodes have emerged as a promising ecofriendly wastewater treatment technology capable of operating on an energy-free basis.However,the inevitable biofouling of ...Microbial fuel cells(MFCs)incorporating air-breathing cathodes have emerged as a promising ecofriendly wastewater treatment technology capable of operating on an energy-free basis.However,the inevitable biofouling of these devices rapidly decreases cathodic catalytic activity and also reduces the stability of MFCs during long-term operation.The present work developed a novel microbial separator for use in air-breathing MFCs that protects cathodic catalytic activity.In these modified devices,microbes preferentially grow on the microbial separator rather than the cathodic surface such that biofouling is prevented.Trials showed that this concept provided low charge transfer and mass diffusion resistance values during the cathodic oxygen reduction reaction of 4.6±1.3 and 17.3±6.8 U,respectively,after prolonged operation.The maximum power density was found to be stable at 1.06±0.07 W m2 throughout a long-term test and the chemical oxygen demand removal efficiency was increased to 92%compared with a value of 83%for MFCs exhibiting serious biofouling.In addition,a cathode combined with a microbial separator demonstrated less cross-cathode diffusion of oxygen to the anolyte.This effect indirectly induced the growth of electroactive bacteria and produced higher currents in air-breathing MFCs.Most importantly,the present microbial separator concept enhances both the lifespan and economics of air-breathing MFCs by removing the need to replace or regenerate the cathode during longterm operation.These results indicate that the installation of a microbial separator is an effective means of stabilizing power generation and ensuring the cost-effective performance of air-breathing MFCs intended for future industrial applications.展开更多
A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish ...A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish Algorithm integrated Perturb and Obserb (IJFA-PO) has been proposed to track the Global Maximum Power Point (GMPP). Second, the main unit-powered via DC–AC converter is synchronised with the grid. To cope with the wide voltage variation and harmonic mitigation, an auxiliary unit undergoes a novel series compensation technique. Out of various switching approaches, IJFA-based Selective Harmonic Elimination (SHE) in 120° conduction gives the optimal solution. Three switching angles were obtained using IJFA, whose performance was equivalent to that of nine switching angles. Thus, the system is efficient with minimised higher-order harmonics and lower switching losses. The proposed system outperformed in terms of efficiency, metaheuristics, and convergence. The Total Harmonic Distortion (THD) obtained was 1.32%, which is within the IEEE 1547 and IEC tolerable limits. The model was developed in MATLAB/Simulink 2016b and verified with an experimental prototype of grid-synchronised PV capacity of 260 W tested under various loading conditions. The present model is reliable and features a simple controller that provides more convenient and adequate performance.展开更多
Selective harmonic elimination pulse width modula-tion(SHEPWM)is a modulation strategy widely used for three-level wind power grid-connected converters.Its purpose is to eliminate specified sub-low frequency harmonics...Selective harmonic elimination pulse width modula-tion(SHEPWM)is a modulation strategy widely used for three-level wind power grid-connected converters.Its purpose is to eliminate specified sub-low frequency harmonics by controlling switching angle.Furthermore,it can reduce fluctuation of the microgrid system and improve system stability.Intelligent al-gorithms have been applied to the SHEPWM solution process to mitigate calculation complexity associated with the algebraic method,as well as the need to set the initial value.However,disorder of the optimization result causes difficulty in satisfying incremental constraint of the three-level NPC switching angles,and affects the success rate of the algorithm.To overcome this limitation,this paper proposes a fast SHEPWM strategy to optimize the result obtained by the intelligent algorithm.The SHEPWM can be realized by solving switching angles through a state equations-based mathematical model,which is constructed by using the initial variables randomly generated by the intelligent algorithm as the disturbance.This mathematical model improves the success rate of calculation by simplifying constraint representation of switching angles and solving the disorder problem of the optimization result.At the same time,a method based on the circle equation and the trigonometric function is applied to the initial variable assignment of the state equation,which further improves the speed and accuracy of the solution,realizes a more thorough filtering effect,and further reduces the impact of sub-low frequency harmonics on a wind power integrated system.Finally,simulation and experiment results have been used to prove the effectiveness of the proposed SHEPWM strategy when combined with intelligent algorithms.Index Terms-Wind power converter,adaptive genetic algorithm,selective harmonic elimination pulse-width modulation(SHEPWM),state equation,success rate.展开更多
This paper presents a unique voltage-raising topology for a single-phase seven-level inverter with triple output voltage gain using single input source and two switched capacitors.The output voltage has been boosted u...This paper presents a unique voltage-raising topology for a single-phase seven-level inverter with triple output voltage gain using single input source and two switched capacitors.The output voltage has been boosted up to three times the value of input voltage by configuring the switched capacitors in series and parallel combinations which eliminates the use of additional step-up converters and transformers.The selective harmonic elimination(SHE)approach is used to remove the lower-order harmonics.The optimal switching angles for SHE is determined using the genetic algorithm.These switching angles are com-bined with a level-shifted pulse width modulation(PWM)technique for pulse generation,resulting in reduced total harmonic distortion(THD).A detailed com-parison has been made against other relevant seven-level inverter topologies in terms of the number of switches,drivers,diodes,capacitors,and boosting facil-ities to emphasize the benefits of the proposed model.The proposed topology is simulated using MATLAB/SIMULINK and an experimental prototype has been developed to validate the results.The Digital Signal Processing(DSP)TMS320F2812 board is used to generate the switching pulses for the proposed technique and the experimental results concur with the simulated model outputs.展开更多
Selective harmonic elimination(SHE) in multilevel inverters is an intricate optimization problem that involves a set of nonlinear transcendental equations which have multiple local minima. A new advanced objective fun...Selective harmonic elimination(SHE) in multilevel inverters is an intricate optimization problem that involves a set of nonlinear transcendental equations which have multiple local minima. A new advanced objective function with proper weighting is proposed and also its efficiency is compared with the objective function which is more similar to the proposed one. To enhance the ability of the SHE in eliminating high number of selected harmonics, at each level of the output voltage, one slot is created. The SHE problem is solved by imperialist competitive algorithm(ICA). The conventional SHE methods cannot eliminate the selected harmonics and satisfy the fundamental component in some ranges of modulation indexes. So, to surmount the SHE defect, a DC-DC converter is applied. Theoretical results are substantiated by simulations and experimental results for a 9-level multilevel inverter. The obtained results illustrate that the proposed method successfully minimizes a large number of identified harmonics which consequences very low total harmonic distortion of output voltage.展开更多
基金the National High Level Talents Special Support Plan(X.C.)the“Young Talent Support Plan”of Xi'an Jiaotong University(X.C.)+2 种基金the Natural Science Foundation of Shaanxi Province(No.2022JZ-48 to X.C.)the National Natural Science Foundation of China(No.82272141 to X.C.)the Shaanxi Provincial Key Research and Development Plan Project(No.2023-JC-QN-0260 to X.Q.).
文摘The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer treatment.Herein,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to treat breast cancer via accurate tumor elimination,on-demand adipose tissue regeneration and effective infection inhibition.The hydrogel consisted of thiol groups ended polyethylene glycol(SH-PEG-SH)and doxorubicin encapsulated mesoporous silica nanocarriers(DOX@MSNs)double crosslinked hyaluronic acid(HA)after loading of antibacterial peptides(AP)and adipose-derived stem cells(ADSCs).A pH-cleavable unsaturated amide bond was pre-introduced between MSNs and HA frame to perform the tumor-specific acidic environment dependent DOX@MSNs release,meanwhile an esterase degradable glyceryl dimethacrylate cap was grafted on MSNs,which contributed to the selective chemotherapy in tumor cells with over-expressed esterase.The bond cleavage between MSNs and HA would also cause the swelling of the hydrogel,which not only provide sufficient space for the growth of ADSCs,but allows the hydrogel to fully fill the irregular defects generated by surgery and residual tumor atrophy,resulting in the on-demand regeneration of adipose tissue.Moreover,the sustained release of AP could be simultaneously triggered along with the size change of hydrogel,which further avoided bacterial infection to promote tissue regeneration.
基金supported by the National Nature Science Foundation of China(Grant No.52100021)the China Postdoctoral Science Foundation(Grants No.2022M720004 and No.2022M710208)。
文摘Microbial fuel cells(MFCs)incorporating air-breathing cathodes have emerged as a promising ecofriendly wastewater treatment technology capable of operating on an energy-free basis.However,the inevitable biofouling of these devices rapidly decreases cathodic catalytic activity and also reduces the stability of MFCs during long-term operation.The present work developed a novel microbial separator for use in air-breathing MFCs that protects cathodic catalytic activity.In these modified devices,microbes preferentially grow on the microbial separator rather than the cathodic surface such that biofouling is prevented.Trials showed that this concept provided low charge transfer and mass diffusion resistance values during the cathodic oxygen reduction reaction of 4.6±1.3 and 17.3±6.8 U,respectively,after prolonged operation.The maximum power density was found to be stable at 1.06±0.07 W m2 throughout a long-term test and the chemical oxygen demand removal efficiency was increased to 92%compared with a value of 83%for MFCs exhibiting serious biofouling.In addition,a cathode combined with a microbial separator demonstrated less cross-cathode diffusion of oxygen to the anolyte.This effect indirectly induced the growth of electroactive bacteria and produced higher currents in air-breathing MFCs.Most importantly,the present microbial separator concept enhances both the lifespan and economics of air-breathing MFCs by removing the need to replace or regenerate the cathode during longterm operation.These results indicate that the installation of a microbial separator is an effective means of stabilizing power generation and ensuring the cost-effective performance of air-breathing MFCs intended for future industrial applications.
文摘A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish Algorithm integrated Perturb and Obserb (IJFA-PO) has been proposed to track the Global Maximum Power Point (GMPP). Second, the main unit-powered via DC–AC converter is synchronised with the grid. To cope with the wide voltage variation and harmonic mitigation, an auxiliary unit undergoes a novel series compensation technique. Out of various switching approaches, IJFA-based Selective Harmonic Elimination (SHE) in 120° conduction gives the optimal solution. Three switching angles were obtained using IJFA, whose performance was equivalent to that of nine switching angles. Thus, the system is efficient with minimised higher-order harmonics and lower switching losses. The proposed system outperformed in terms of efficiency, metaheuristics, and convergence. The Total Harmonic Distortion (THD) obtained was 1.32%, which is within the IEEE 1547 and IEC tolerable limits. The model was developed in MATLAB/Simulink 2016b and verified with an experimental prototype of grid-synchronised PV capacity of 260 W tested under various loading conditions. The present model is reliable and features a simple controller that provides more convenient and adequate performance.
基金supported in part by National Natural Science Foundation of China(52177193)Key Research and Development Program of Shaanxi Province(2022GY-182)+1 种基金China Scholarship Council(CSC)State Scholarship Fund International Clean Energy Talent Project(Grant No.[2018]5046,[2019]157)Open Research Fund of Jiangsu Collaborative Innovation Center for Smart Distribution Network,Nanjing Institute of Technology(XTCX202107).
文摘Selective harmonic elimination pulse width modula-tion(SHEPWM)is a modulation strategy widely used for three-level wind power grid-connected converters.Its purpose is to eliminate specified sub-low frequency harmonics by controlling switching angle.Furthermore,it can reduce fluctuation of the microgrid system and improve system stability.Intelligent al-gorithms have been applied to the SHEPWM solution process to mitigate calculation complexity associated with the algebraic method,as well as the need to set the initial value.However,disorder of the optimization result causes difficulty in satisfying incremental constraint of the three-level NPC switching angles,and affects the success rate of the algorithm.To overcome this limitation,this paper proposes a fast SHEPWM strategy to optimize the result obtained by the intelligent algorithm.The SHEPWM can be realized by solving switching angles through a state equations-based mathematical model,which is constructed by using the initial variables randomly generated by the intelligent algorithm as the disturbance.This mathematical model improves the success rate of calculation by simplifying constraint representation of switching angles and solving the disorder problem of the optimization result.At the same time,a method based on the circle equation and the trigonometric function is applied to the initial variable assignment of the state equation,which further improves the speed and accuracy of the solution,realizes a more thorough filtering effect,and further reduces the impact of sub-low frequency harmonics on a wind power integrated system.Finally,simulation and experiment results have been used to prove the effectiveness of the proposed SHEPWM strategy when combined with intelligent algorithms.Index Terms-Wind power converter,adaptive genetic algorithm,selective harmonic elimination pulse-width modulation(SHEPWM),state equation,success rate.
文摘This paper presents a unique voltage-raising topology for a single-phase seven-level inverter with triple output voltage gain using single input source and two switched capacitors.The output voltage has been boosted up to three times the value of input voltage by configuring the switched capacitors in series and parallel combinations which eliminates the use of additional step-up converters and transformers.The selective harmonic elimination(SHE)approach is used to remove the lower-order harmonics.The optimal switching angles for SHE is determined using the genetic algorithm.These switching angles are com-bined with a level-shifted pulse width modulation(PWM)technique for pulse generation,resulting in reduced total harmonic distortion(THD).A detailed com-parison has been made against other relevant seven-level inverter topologies in terms of the number of switches,drivers,diodes,capacitors,and boosting facil-ities to emphasize the benefits of the proposed model.The proposed topology is simulated using MATLAB/SIMULINK and an experimental prototype has been developed to validate the results.The Digital Signal Processing(DSP)TMS320F2812 board is used to generate the switching pulses for the proposed technique and the experimental results concur with the simulated model outputs.
文摘Selective harmonic elimination(SHE) in multilevel inverters is an intricate optimization problem that involves a set of nonlinear transcendental equations which have multiple local minima. A new advanced objective function with proper weighting is proposed and also its efficiency is compared with the objective function which is more similar to the proposed one. To enhance the ability of the SHE in eliminating high number of selected harmonics, at each level of the output voltage, one slot is created. The SHE problem is solved by imperialist competitive algorithm(ICA). The conventional SHE methods cannot eliminate the selected harmonics and satisfy the fundamental component in some ranges of modulation indexes. So, to surmount the SHE defect, a DC-DC converter is applied. Theoretical results are substantiated by simulations and experimental results for a 9-level multilevel inverter. The obtained results illustrate that the proposed method successfully minimizes a large number of identified harmonics which consequences very low total harmonic distortion of output voltage.
