Electrically controlled solid propellant(ECSP)offers multiple ignition and adjustable burning rate,serving as fuel for next-generation intelligent propulsion systems.To further enhance the combustion performance of EC...Electrically controlled solid propellant(ECSP)offers multiple ignition and adjustable burning rate,serving as fuel for next-generation intelligent propulsion systems.To further enhance the combustion performance of ECSP,a method utilizing electrochemical and thermal decomposition catalysts has been proposed.In this work,we investigated the combustion characteristics of hydroxylamine nitrate(HAN)-based ECSP incorporating cerium oxide(CeO_(2))and graphene oxide(GO)by using an electrically controlled combustion test system.Electrochemical impedance spectroscopy(EIS)and linear sweep voltammetry(LSV)were used to measure the electrical conductibility and overpotential of ECSP with various additives,and Tafel curves were calculated.Thermogravimetric analysis coupled with differential scanning calorimetry(TG-DSC)was employed to investigate the thermal decomposition behavior of ECSP.While the addition of CeO_(2) and GO reduced the conductivity of ECSP,both catalysts exhibited strong electrocatalytic properties and facilitated the thermal decomposition of ECSP.Between two catalysts,GO demonstrated superior electrochemical catalytic performance but weaker thermal decomposition catalytic ability than CeO_(2).The addition of catalysts significantly enhanced the combustion performance of HAN-based ECSP.Specifically,the ignition delay time was shortened by 10%~20%.CeO_(2) raised the burning rate by approximately 20%but GO exhibited a remarkable boost of 40%in burning rate at high voltage.The combination of GO and PVA produced a flame-retardant substance that negatively impacted the ignition delay of ECSP and resulted in a smaller increase in the burning rate of ECSP at low ignition voltages.展开更多
Arc fault detection is desperately required in Solid State Power Controllers（SSPC） in addition to their fundamental functions because arcs will provoke growing harm and threat to aircraft safety. Experimental study ...Arc fault detection is desperately required in Solid State Power Controllers（SSPC） in addition to their fundamental functions because arcs will provoke growing harm and threat to aircraft safety. Experimental study has been done to obtain the faulted current data. In order to improve the detection speed and accuracy, two fast arc fault detection methods have been proposed in this paper with the analysis of only half cycle data. Both Fast Fourier Transform（FFT） and Wavelet Packets Decomposition（WPD） have been adopted to distinguish arc fault currents from normal operation currents. Analysis results show that Alternating Current（AC） arcs can be effectively and accurately detected with the proposed half cycle data based methods. Moreover,experimental verification results have also been provided.展开更多
The solid state photochemical reaction of nitrobenzaldehyde with indole was investigated. Seven hey products were identified by IR, MS,^(1)H HMR and elemental analysis.
The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP)can be classified into fixed and movable types.In movable electrode structures,springs are typically used to push the ele...The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP)can be classified into fixed and movable types.In movable electrode structures,springs are typically used to push the electrodes and the propellant.The effects of spring pressure on the ignition and combustion of propellants have not yet been studied.In this paper,a universal testing machine and an electrochemical workstation were firstly utilized to investigate the compressive mechanical property and conductivity of Hydroxylamine Nitrate(HAN)-ECSP.The maximum pressure at which the propellant undergoes elastic deformation is 65 kPa.When the spring pressure increased from 5.1 kPa to 20.4 kPa,the propellant resistance decreased from 56.8 X to 36.8 X.Various observation methods were employed to study the process of electrical energy injection and the ignition and combustion characteristics under constant voltage.Appropriately increasing the spring pressure can accelerate the injection of electrical energy into the propellant,increase the electrification current,and thus reduce the initial ignition delay time of the propellant.When the spring pressure is 20.4 kPa,the squeezing speed of the propellant is too fast,making it difficult for the propellant to be adequately heated at the electrode interface,which is unfavorable for ignition.Excessive spring pressure also leads to the accumulation of a large amount of combustion residue on the electrode plate,hindering the mixing and diffusion of hot gases during the second ignition process,preventing the gaseous flame of the propellant.When the spring pressure is 5.1 kPa,improving the working voltage can enhance the repeated ignition characteristics of the propellant.展开更多
The variation of mass, and moment of inertia of a spin-stabilized spacecraft leads to concern about the nutation instability. Here a careful analysis on the nutation instability is performed on a spacecraft propelled ...The variation of mass, and moment of inertia of a spin-stabilized spacecraft leads to concern about the nutation instability. Here a careful analysis on the nutation instability is performed on a spacecraft propelled by solid rocket booster（SRB）. The influences of specific solid propellant designs on transversal angular velocity are discussed. The results show that the typical SRB of End Burn suppresses the non-principal axial angular velocity. On the contrary, the frequently used SRB of Radial Burn could amplify the transversal angular velocity. The nutation instability caused by a design of Radial Burn could be remedied by the addition of End Burn at the same time based on the study of the combination design of both End Burn and Radial Burn.The analysis of the results proposes the design conception of how to control the nutation motion.The method is suitable to resolve the nutation instability of solid rocket motor with complex propellant patterns.展开更多
Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution rate.However,most new chemical entities exhibit poor water solubility,and he...Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution rate.However,most new chemical entities exhibit poor water solubility,and hence are exempt from such benefits.Although combining drug amorphization with controlled release formulation is promising to elevate drug solubility,like other supersaturating systems,the problem of drug recrystallization has yet to be resolved,particularly within the dosage form.Here,we explored the potential of an emerging,non-leachable terpolymer nanoparticle(TPN)pore former as an internal recrystallization inhibitor within controlled release amorphous solid dispersion(CRASD)beads comprising a poorly soluble drug(celecoxib)reservoir and insoluble polymer(ethylcellulose)membrane.Compared to conventional pore former,polyvinylpyrrolidone(PVP),TPN-containing membranes exhibited superior structural integrity,less crystal formation at the CRASD bead surface,and greater extent of celecoxib release.All-atom molecular dynamics analyses revealed that in the presence of TPN,intra-molecular bonding,crystal formation tendency,diffusion coefficient,and molecular flexibility of celecoxib were reduced,while intermolecular H-bonding was increased as compared to PVP.This work suggests that selection of a pore former that promotes prolonged molecular separation within a nanoporous controlled release membrane structure may serve as an effective strategy to enhance amorphicity preservation inside CRASD.展开更多
In this work, we report a simple and inexpensive approach to synthesize effective multicomponent Cu-Cu2O-CuO catalysts for the Rochow process from industrial waste contact masses （WCMs）. WCMs from the organosilane i...In this work, we report a simple and inexpensive approach to synthesize effective multicomponent Cu-Cu2O-CuO catalysts for the Rochow process from industrial waste contact masses （WCMs）. WCMs from the organosilane industry were treated with acid followed by reduction with metallic iron powder. The obtained copper powder was then subjected to controlled oxidation in air at different temperatures, followed by ball milling. The orthogonal array approach was applied to optimize this process, and the stirring speed and pH were found to significantly affect the leaching ratio and copper yield, respectively. When used for the Rochow process, the optimized ternary Cu-Cu2O-CuO catalyst greatly enhanced the dimethyldichlorosilane selectivity and Si conversion compared with Cu-Cu2O-CuO catalysts prepared without ball milling, bare Cu catalysts, and Cu-Cu2O-CuO catalysts with different compositions. This could be attributed to their small particle size and the strong synergistic effect among the multiple components in the catalyst with the optimized composition.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12074187).
文摘Electrically controlled solid propellant(ECSP)offers multiple ignition and adjustable burning rate,serving as fuel for next-generation intelligent propulsion systems.To further enhance the combustion performance of ECSP,a method utilizing electrochemical and thermal decomposition catalysts has been proposed.In this work,we investigated the combustion characteristics of hydroxylamine nitrate(HAN)-based ECSP incorporating cerium oxide(CeO_(2))and graphene oxide(GO)by using an electrically controlled combustion test system.Electrochemical impedance spectroscopy(EIS)and linear sweep voltammetry(LSV)were used to measure the electrical conductibility and overpotential of ECSP with various additives,and Tafel curves were calculated.Thermogravimetric analysis coupled with differential scanning calorimetry(TG-DSC)was employed to investigate the thermal decomposition behavior of ECSP.While the addition of CeO_(2) and GO reduced the conductivity of ECSP,both catalysts exhibited strong electrocatalytic properties and facilitated the thermal decomposition of ECSP.Between two catalysts,GO demonstrated superior electrochemical catalytic performance but weaker thermal decomposition catalytic ability than CeO_(2).The addition of catalysts significantly enhanced the combustion performance of HAN-based ECSP.Specifically,the ignition delay time was shortened by 10%~20%.CeO_(2) raised the burning rate by approximately 20%but GO exhibited a remarkable boost of 40%in burning rate at high voltage.The combination of GO and PVA produced a flame-retardant substance that negatively impacted the ignition delay of ECSP and resulted in a smaller increase in the burning rate of ECSP at low ignition voltages.
基金co-supported by the National Natural Science Foundation of China(Nos.51407144 and 51777169)the Aviation Research Funds(No.20164053029)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.3102017ZY027 and 3102017GX08001)the Young Elite Scientist Sponsorship Program by CAST
文摘Arc fault detection is desperately required in Solid State Power Controllers（SSPC） in addition to their fundamental functions because arcs will provoke growing harm and threat to aircraft safety. Experimental study has been done to obtain the faulted current data. In order to improve the detection speed and accuracy, two fast arc fault detection methods have been proposed in this paper with the analysis of only half cycle data. Both Fast Fourier Transform（FFT） and Wavelet Packets Decomposition（WPD） have been adopted to distinguish arc fault currents from normal operation currents. Analysis results show that Alternating Current（AC） arcs can be effectively and accurately detected with the proposed half cycle data based methods. Moreover,experimental verification results have also been provided.
文摘The solid state photochemical reaction of nitrobenzaldehyde with indole was investigated. Seven hey products were identified by IR, MS,^(1)H HMR and elemental analysis.
基金supported by the National Natural Science Foundation of China(Nos.T222100,22205258,52302485 and 2024JJ5404).
文摘The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP)can be classified into fixed and movable types.In movable electrode structures,springs are typically used to push the electrodes and the propellant.The effects of spring pressure on the ignition and combustion of propellants have not yet been studied.In this paper,a universal testing machine and an electrochemical workstation were firstly utilized to investigate the compressive mechanical property and conductivity of Hydroxylamine Nitrate(HAN)-ECSP.The maximum pressure at which the propellant undergoes elastic deformation is 65 kPa.When the spring pressure increased from 5.1 kPa to 20.4 kPa,the propellant resistance decreased from 56.8 X to 36.8 X.Various observation methods were employed to study the process of electrical energy injection and the ignition and combustion characteristics under constant voltage.Appropriately increasing the spring pressure can accelerate the injection of electrical energy into the propellant,increase the electrification current,and thus reduce the initial ignition delay time of the propellant.When the spring pressure is 20.4 kPa,the squeezing speed of the propellant is too fast,making it difficult for the propellant to be adequately heated at the electrode interface,which is unfavorable for ignition.Excessive spring pressure also leads to the accumulation of a large amount of combustion residue on the electrode plate,hindering the mixing and diffusion of hot gases during the second ignition process,preventing the gaseous flame of the propellant.When the spring pressure is 5.1 kPa,improving the working voltage can enhance the repeated ignition characteristics of the propellant.
基金supported by the National Natural Science Foundation of China (Nos. 11502086 and 11502087)
文摘The variation of mass, and moment of inertia of a spin-stabilized spacecraft leads to concern about the nutation instability. Here a careful analysis on the nutation instability is performed on a spacecraft propelled by solid rocket booster（SRB）. The influences of specific solid propellant designs on transversal angular velocity are discussed. The results show that the typical SRB of End Burn suppresses the non-principal axial angular velocity. On the contrary, the frequently used SRB of Radial Burn could amplify the transversal angular velocity. The nutation instability caused by a design of Radial Burn could be remedied by the addition of End Burn at the same time based on the study of the combination design of both End Burn and Radial Burn.The analysis of the results proposes the design conception of how to control the nutation motion.The method is suitable to resolve the nutation instability of solid rocket motor with complex propellant patterns.
基金supported in part by an Ontario Research Fund-Research Excellence(ORF-RE)grant(Ontario,Canada)in partnership with Patheon by Thermo Fisher Scientific,Natural Sciences and Engineering Research Council(NSERC)of Canada Discovery Grant and Equipment Grants to Xiao Yu Wu,University of Toronto(Canada),Leslie Dan Faculty of Pharmacy Dean's Fund to Jamie Anne Lugtu-Pe,University of Toronto(Canada),Mitacs Accelerate Internship sponsored by Candoo Pharmatech Company Inc.to Xuning Zhang(Canada),NSERC CREATE ContRoL program support to Sako Mirzaie and Hao Han R.Chang(Canada),Ontario Graduate Scholarship(OGS)to Hao Han R.Chang(Canada),and Pharmaceutical Sciences graduate department scholarships to Hao Han R.Chang and Kuan Chen,University of Toronto(Canada).
文摘Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution rate.However,most new chemical entities exhibit poor water solubility,and hence are exempt from such benefits.Although combining drug amorphization with controlled release formulation is promising to elevate drug solubility,like other supersaturating systems,the problem of drug recrystallization has yet to be resolved,particularly within the dosage form.Here,we explored the potential of an emerging,non-leachable terpolymer nanoparticle(TPN)pore former as an internal recrystallization inhibitor within controlled release amorphous solid dispersion(CRASD)beads comprising a poorly soluble drug(celecoxib)reservoir and insoluble polymer(ethylcellulose)membrane.Compared to conventional pore former,polyvinylpyrrolidone(PVP),TPN-containing membranes exhibited superior structural integrity,less crystal formation at the CRASD bead surface,and greater extent of celecoxib release.All-atom molecular dynamics analyses revealed that in the presence of TPN,intra-molecular bonding,crystal formation tendency,diffusion coefficient,and molecular flexibility of celecoxib were reduced,while intermolecular H-bonding was increased as compared to PVP.This work suggests that selection of a pore former that promotes prolonged molecular separation within a nanoporous controlled release membrane structure may serve as an effective strategy to enhance amorphicity preservation inside CRASD.
基金The work was supported by the National Natural Science Foundation of China （grant number 21506224）. Z.Z. is grateful for support from the Institute of Chemical and Engineering Sciences.
文摘In this work, we report a simple and inexpensive approach to synthesize effective multicomponent Cu-Cu2O-CuO catalysts for the Rochow process from industrial waste contact masses （WCMs）. WCMs from the organosilane industry were treated with acid followed by reduction with metallic iron powder. The obtained copper powder was then subjected to controlled oxidation in air at different temperatures, followed by ball milling. The orthogonal array approach was applied to optimize this process, and the stirring speed and pH were found to significantly affect the leaching ratio and copper yield, respectively. When used for the Rochow process, the optimized ternary Cu-Cu2O-CuO catalyst greatly enhanced the dimethyldichlorosilane selectivity and Si conversion compared with Cu-Cu2O-CuO catalysts prepared without ball milling, bare Cu catalysts, and Cu-Cu2O-CuO catalysts with different compositions. This could be attributed to their small particle size and the strong synergistic effect among the multiple components in the catalyst with the optimized composition.
