Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protect...Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protection,such as temperature-responsive electrodes,and thermal-shutdown separators,these methods only provide irreversible protection.Recently,reversible temperature-sensitive electrolytes have emerged as promising alternatives,offering both thermo-reversibility and self-protective properties.However,further research is crucial to fully understand these thermal-shutdown electrolytes.In this study,we propose lower critical solution temperature(LCST)phase behavior poly(benzyl methacrylate)/imidazolium-based ionic liquid mixtures to prepare temperature-sensitive electrolytes that provide reversible thermal shutdown protection of batteries.This electrolyte features an appropriate protection temperature(~105℃)and responds quickly within a 1 min at 105℃,causing cells to hardly discharge as the voltage suddenly drops to 3.38 V,and providing efficient thermal shutdown protection within 30 min.Upon cooling back to room temperature,the battery regains its original performance.Additionally,the electrolyte exhibits excellent cycling stability with the capacity retention of the battery is 91.6%after 500 cycles.This work provides a viable solution for preventing batteries from thermal runaway triggered by overheating.展开更多
Photo-assisted SCR(PSCR) offers a potential solution for removal of NO at room temperature. MnTiO_(x)as PSCR catalyst exhibits superior performance with NO removal of 100% at the room temperature. Electron paramagneti...Photo-assisted SCR(PSCR) offers a potential solution for removal of NO at room temperature. MnTiO_(x)as PSCR catalyst exhibits superior performance with NO removal of 100% at the room temperature. Electron paramagnetic resonance(EPR) analysis revealed the presence of numerous oxygen vacancies on MnTiO_(x). Optical carrier density functional theory(DFT) calculations showed that the threedimensional orbital hybridization of Mn and Ti is significantly enhanced under light irradiation. The MnTiO_(x)catalyst exhibited excellent electron–hole separation ability, which can adsorbe NH_(3)and dissociate to form NH_(2)fragments and H atoms. In-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS) indicated that the optical carrier enhanced NH_(3)adsorption on MnTiO_(x), which makes it possess excellent PSCR activity. This work provided an additional strategy to NO removal with PSCR catalysts and showed potential for use in photocatalysis.展开更多
We rationally designed a high performance denitration(De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti(CP-SD)catalyst for selective catalytic reduction(SCR). This was prepared by a co-precipitatio...We rationally designed a high performance denitration(De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti(CP-SD)catalyst for selective catalytic reduction(SCR). This was prepared by a co-precipitation and spray drying(CP-SD) method. The catalyst was systematically characterized, and its morphological structure and surface properties were identified. Compare with conventional Mn–Ce–Fe–Ti(CP) catalysts, the Mn–Ce–Fe–Ti(CP-SD) catalyst had superior surface-adsorbed oxygen leading to enhanced 'fast NH3-SCR' reaction. The asobtained Mn–Ce–Fe–Ti(CP-SD) catalyst offered excellent NO conversion and N2 selectivity of 100.0% and 84.8% at 250℃, respectively, with a gas hourly space velocity(GHSV) of 40,000 h-1. The porous micro-spherical structure provides a larger surface area and more active sites to adsorb and activate the reaction gases. In addition, the uniform distribution and strong interaction of manganese, iron, cerium, and titanium oxide species improved H2O and SO2 resistance. The results showed that the Mn–Ce–Fe–Ti(CP-SD) catalyst could be used prospectively as a denitration(De-NOx) catalyst.展开更多
Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still car...Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.展开更多
This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most se...This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most serious influence in multicore fiber transmission process. Before the experiment, the affecting factors of fiber crosstalk were analyzed through simulation, such as core space, bending radius, and fiber length. Combined with the simulation analysis, the design scheme of multicore fiber with low crosstalk was obtained. Before the fiber design, various factors of influence crosstalk such as the core- to-core distance, bending radius, fiber length and so on. Based on the simulation analysis, conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk. The space division multiplexing and wavelength division multiplexing technology, was adopted to conduct seven-core optical fiber transmission of 58.7kin.The crosstalk of adjacent core was suppressed to as low as 45dB / km, the attenuation of inner core was 0.24dB/ km, the outer cores＇ 0.32dB/km. Different bit error rate （BER） performances were also studied under different conditions, through reasonably designing the system to reduce the error rate, improve the performance of the system, and realize long distance and large capacity transmission with fiber.展开更多
汽车功能安全是保证汽车安全的关键技术,危险事件识别是汽车功能安全过程中的重要环节,本文通过利用危险与可操作性分析方法(HAZOP,Hazard and Operability Analysis),选取6种引导词对汽车的电子液压制动系统(EHB,Electronic-hydraulic ...汽车功能安全是保证汽车安全的关键技术,危险事件识别是汽车功能安全过程中的重要环节,本文通过利用危险与可操作性分析方法(HAZOP,Hazard and Operability Analysis),选取6种引导词对汽车的电子液压制动系统(EHB,Electronic-hydraulic Brake)进行了潜在危险事件识别,详细介绍了HAZOP分析方法的相关项定义、危害分析、风险评估等过程,所得到的潜在危险事件能够有效帮助研发人员进行汽车EHB制动系统的功能安全分析,提高系统的可靠性。展开更多
Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and ...Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and lattice dynamics simulations,we studied phonon transport in SiC materials with an SF.Compared to perfect SiC materials,the SF can reduce thermal conductivity.This is caused by the additional interface thermal resistance(ITR)of SF,which is difficult to capture by the previous phenomenological models.By analyzing the spectral heat flux,we find that SF reduces the contribution of low-frequency(7.5 THz-12 THz)phonons to the heat flux,which can be attributed to SF reducing the phonon lifetime and group velocity,especially in the low-frequency range.The SF hinders phonon transport and results in an effective interface thermal resistance around the SF.Our results provide insight into the microscopic mechanism of the effect of defects on heat transport and have guiding significance for the regulation of the thermal conductivity of materials.展开更多
With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical netwo...With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical networks,this paper proposes a bee colony optimization algorithm for routing and wavelength assignment based on directional guidance(DBCO-RWA)in satellite optical networks.In D-BCORWA,directional guidance based on relative position and link load is defined,and then the link cost function in the path search stage is established based on the directional guidance factor.Finally,feasible solutions are expanded in the global optimization stage.The wavelength utilization,communication success probability,blocking rate,communication hops and convergence characteristic are simulated.The results show that the performance of the proposed algorithm is improved compared with existing algorithms.展开更多
In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are car...In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are carried out and then the modeling scheme of few-mode multicore optical fiber channel based on non-uniform mode field distribution is put forward. The proposed modeling scheme can not only exponentially increases the system capacity through fewmode multi-core optical fiber channel, but has better transmission performance compared to the channel of the same type to the uniform channel revealing from the simulation results.展开更多
基金funded by the National Natural Science Foundation of China(no.22075155)the Zhejiang Provincial Natural Science Foundation of China(No.LY24B030002)+2 种基金Ningbo Natural Science Foundation(2023J089)the China Scholarship Council(CSC)the Ningbo Science and Technology Bureau(2024QL036).
文摘Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protection,such as temperature-responsive electrodes,and thermal-shutdown separators,these methods only provide irreversible protection.Recently,reversible temperature-sensitive electrolytes have emerged as promising alternatives,offering both thermo-reversibility and self-protective properties.However,further research is crucial to fully understand these thermal-shutdown electrolytes.In this study,we propose lower critical solution temperature(LCST)phase behavior poly(benzyl methacrylate)/imidazolium-based ionic liquid mixtures to prepare temperature-sensitive electrolytes that provide reversible thermal shutdown protection of batteries.This electrolyte features an appropriate protection temperature(~105℃)and responds quickly within a 1 min at 105℃,causing cells to hardly discharge as the voltage suddenly drops to 3.38 V,and providing efficient thermal shutdown protection within 30 min.Upon cooling back to room temperature,the battery regains its original performance.Additionally,the electrolyte exhibits excellent cycling stability with the capacity retention of the battery is 91.6%after 500 cycles.This work provides a viable solution for preventing batteries from thermal runaway triggered by overheating.
基金supported by Science and Technology Innovation Talents Program of Bingtuan (No.2019CB025)Major Scientific and Technological Project of Bingtuan (No.2018AA002)Project of Regional Innovation in Bingtuan (No.2021BB005)。
文摘Photo-assisted SCR(PSCR) offers a potential solution for removal of NO at room temperature. MnTiO_(x)as PSCR catalyst exhibits superior performance with NO removal of 100% at the room temperature. Electron paramagnetic resonance(EPR) analysis revealed the presence of numerous oxygen vacancies on MnTiO_(x). Optical carrier density functional theory(DFT) calculations showed that the threedimensional orbital hybridization of Mn and Ti is significantly enhanced under light irradiation. The MnTiO_(x)catalyst exhibited excellent electron–hole separation ability, which can adsorbe NH_(3)and dissociate to form NH_(2)fragments and H atoms. In-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS) indicated that the optical carrier enhanced NH_(3)adsorption on MnTiO_(x), which makes it possess excellent PSCR activity. This work provided an additional strategy to NO removal with PSCR catalysts and showed potential for use in photocatalysis.
基金supported by Major Scientific and Technological Project of Bingtuan (No.2018AA002)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R46)
文摘We rationally designed a high performance denitration(De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti(CP-SD)catalyst for selective catalytic reduction(SCR). This was prepared by a co-precipitation and spray drying(CP-SD) method. The catalyst was systematically characterized, and its morphological structure and surface properties were identified. Compare with conventional Mn–Ce–Fe–Ti(CP) catalysts, the Mn–Ce–Fe–Ti(CP-SD) catalyst had superior surface-adsorbed oxygen leading to enhanced 'fast NH3-SCR' reaction. The asobtained Mn–Ce–Fe–Ti(CP-SD) catalyst offered excellent NO conversion and N2 selectivity of 100.0% and 84.8% at 250℃, respectively, with a gas hourly space velocity(GHSV) of 40,000 h-1. The porous micro-spherical structure provides a larger surface area and more active sites to adsorb and activate the reaction gases. In addition, the uniform distribution and strong interaction of manganese, iron, cerium, and titanium oxide species improved H2O and SO2 resistance. The results showed that the Mn–Ce–Fe–Ti(CP-SD) catalyst could be used prospectively as a denitration(De-NOx) catalyst.
基金supported by the National Natural Science Foundation of China (U1303291)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R46)
文摘Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.
基金National High Technology 863 Program of China(No.2013AA013301,2013AA013403,2015AA015501,2015AA015502,2015AA015504,2015AA016901)National NSFC(No.61425022/61522501/61307086/61475024/61275158/61201151/61275074/61205066)+4 种基金Beijing Nova Program(No.Z141101001814048)Beijing Excellent Ph.D.Thesis Guidance Foundation(No.20121001302)the Universities Ph.D.Special Research Funds(No.20120005110003/20120005120007)the Fundamental Research Funds for the Central Universities with No.2014RC0203Fund of State Key Laboratory of IPOC(BUPT)
文摘This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most serious influence in multicore fiber transmission process. Before the experiment, the affecting factors of fiber crosstalk were analyzed through simulation, such as core space, bending radius, and fiber length. Combined with the simulation analysis, the design scheme of multicore fiber with low crosstalk was obtained. Before the fiber design, various factors of influence crosstalk such as the core- to-core distance, bending radius, fiber length and so on. Based on the simulation analysis, conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk. The space division multiplexing and wavelength division multiplexing technology, was adopted to conduct seven-core optical fiber transmission of 58.7kin.The crosstalk of adjacent core was suppressed to as low as 45dB / km, the attenuation of inner core was 0.24dB/ km, the outer cores＇ 0.32dB/km. Different bit error rate （BER） performances were also studied under different conditions, through reasonably designing the system to reduce the error rate, improve the performance of the system, and realize long distance and large capacity transmission with fiber.
文摘汽车功能安全是保证汽车安全的关键技术,危险事件识别是汽车功能安全过程中的重要环节,本文通过利用危险与可操作性分析方法(HAZOP,Hazard and Operability Analysis),选取6种引导词对汽车的电子液压制动系统(EHB,Electronic-hydraulic Brake)进行了潜在危险事件识别,详细介绍了HAZOP分析方法的相关项定义、危害分析、风险评估等过程,所得到的潜在危险事件能够有效帮助研发人员进行汽车EHB制动系统的功能安全分析,提高系统的可靠性。
基金Sichuan Science and Technology Program(Grant No.2023NSFSC0044)the National Natural Science Foundation of China(Grant No.51501119)+1 种基金the Fundamental Research Funds for the Central Universitiespartially supported by the High-Performance Computing Center at Sichuan University。
文摘Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and lattice dynamics simulations,we studied phonon transport in SiC materials with an SF.Compared to perfect SiC materials,the SF can reduce thermal conductivity.This is caused by the additional interface thermal resistance(ITR)of SF,which is difficult to capture by the previous phenomenological models.By analyzing the spectral heat flux,we find that SF reduces the contribution of low-frequency(7.5 THz-12 THz)phonons to the heat flux,which can be attributed to SF reducing the phonon lifetime and group velocity,especially in the low-frequency range.The SF hinders phonon transport and results in an effective interface thermal resistance around the SF.Our results provide insight into the microscopic mechanism of the effect of defects on heat transport and have guiding significance for the regulation of the thermal conductivity of materials.
基金supported in part by the National Key Research and Development Program of China under Grant 2021YFB2900604in part by the National Natural Science Foundation of China(NSFC)under Grant U22B2033,61975234,61875230。
文摘With the development of satellite communication,in order to solve the problems of shortage of on-board resources and refinement of delay requirements to improve the communication performance of satellite optical networks,this paper proposes a bee colony optimization algorithm for routing and wavelength assignment based on directional guidance(DBCO-RWA)in satellite optical networks.In D-BCORWA,directional guidance based on relative position and link load is defined,and then the link cost function in the path search stage is established based on the directional guidance factor.Finally,feasible solutions are expanded in the global optimization stage.The wavelength utilization,communication success probability,blocking rate,communication hops and convergence characteristic are simulated.The results show that the performance of the proposed algorithm is improved compared with existing algorithms.
基金supports from National High Technology 863 Program of China(No.2013AA013403,2015AA015501,2015AA015502,2015AA015504)National NSFC(No.61425022/61522501/61307086/61475024/61275158/61201151/61275074/61372109)+4 种基金Beijing Nova Program(No.Z141101001814048)Beijing Excellent Ph.D.Thesis Guidance Foundation(No.20121001302)the Universities Ph.D.Special Research Funds(No.20120005110003/20120005120007)Fund of State Key Laboratory of IPOC(BUPT)P.R.China
文摘In this paper, the influencing factors that affect few-mode and multi core optical fiber channel are analyzed in a comprehensive way. The theoretical modeling and computer simulation of the information channel are carried out and then the modeling scheme of few-mode multicore optical fiber channel based on non-uniform mode field distribution is put forward. The proposed modeling scheme can not only exponentially increases the system capacity through fewmode multi-core optical fiber channel, but has better transmission performance compared to the channel of the same type to the uniform channel revealing from the simulation results.
