The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF...The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.展开更多
CZTS(Cu_(2)ZnSnS_(4))is a quaternary semiconductor that is environmentally friendly,less expensive.In this paper,we report on the optimization and fabrication of CZTS-based heterojunction nanodevices for bifunctional ...CZTS(Cu_(2)ZnSnS_(4))is a quaternary semiconductor that is environmentally friendly,less expensive.In this paper,we report on the optimization and fabrication of CZTS-based heterojunction nanodevices for bifunctional applications such as solar cells and photodetectors.CZTS thin films were deposited on top of(Molybdenum)Mo-coated glass substrates via RF sputtering at 100 and 200 W.Rapid thermal processing(RTP)was used at 300,400,and 500℃temperatures.Cd S(cadmium sulphide)was deposited on CZTS using a chemical bath deposition system with 3-and 5-min deposition times.Zn O(zinc oxide)and AZO(aluminium doped zinc oxide)layers were deposited using RF(radio frequency)sputtering to create the solar device.XRD confirms the formation of a tetragonal structure with increased crystallinity due to the use of RTP.Raman reveals the characteristic Raman shift peak associated with CZTS at 336 and 335 cm^(-1).The FESEM shows a relationship with RTP temperature.Surface features,including grain size,vary with RTP temperature.The ideality factor is nearly 2,indicating imperfection in the Mo/CZTS interface.Schottky barrier height estimates range from 0.6 to 0.7 e V.Absorbance and transmittance show a predictable fluctuation with RTP temperature.Photovoltaic device was built using the higher crystalline feature of CZTS in conjunction with Cd S deposited at 3 and 5 min.The efficiency of Cd S deposited after 3 and 5 min was 1.15 and 0.97 percent,respectively.Fabricated devices were used for wavelength-dependent photodetection.This work demonstrated self-powered photodetection.展开更多
In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of co...In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of copper strips connected to a capacitor at either end,is typically employed as a vacuum chamber to mitigate eddy current effects and beam coupling impedance.Consequently,the ceramic chamber exhibits a thin-walled multilayered complex structure.Previous theoretical studies have suggested that the impedance of such a structure has a negligible impact on the beam.However,recent impedance measurements of the ceramic chamber in the China Spallation Neutron Source(CSNS)RCS revealed a resonance in the low-frequency range,which was confirmed by further theoretical analysis as a source of beam instability in the RCS.Currently,the magnitude of this impedance cannot be accurately assessed using theoretical calculations.In this study,we used the CST Microwave Studio to confirm the impedance of the ceramic chamber.Further simulations covering six different types of ceramic chambers were conducted to develop an impedance model in the RCS.Additionally,this study investigates the resonant characteristics of the ceramic chamber impedance,finding that the resonant frequency is closely related to the capacitance of the capacitors.This finding provides clear directions for further impedance optimization and is crucial for achieving a beam power of 500 kW for the CSNS Phase-Ⅱ project(CSNS-Ⅱ).However,careful attention must be paid to the voltage across the capacitors.展开更多
Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for mari...Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for maritime rockets.The suggested approach introduces a hybrid model that combines random forest(RF)and Adaptive boosting(Ada Boost)methods to describe the coupling mechanism of factors affecting rocket rolling and to suppress the rolling.This combination improves forecast accuracy.Thereafter,the dimensionality reduced response surfaces are used to visually present the coupling between rocket rolling and influencing factors,which reveals the prelaunch rolling mechanism.When angle between the launch device and the ship's bow is within 80°-100°,the dynamic friction coefficient between adapters and guideways is 0.4,and the dynamic friction coefficient between the rocket and launchpad is within 0-0.15 or0.5-0.7,the prelaunch rolling of rocket during one motion cycle of the ship is less than 0.065°,originally 0.27°,reduced by 75.93%,effectively suppressing the prelaunch rolling.This study improves the prelaunch stability of maritime rockets in rough sea conditions and establishes a mapping relationship between the factors affecting rocket rolling and the structure of the sea launch system,guiding the optimization of future sea launch systems.展开更多
基金National Natural Science Foundation of China(11875039)Shanxi Scholarship Council of China(2023-033)+2 种基金Fundamental Research Program of Shanxi Province(202303021221071)China Baowu Low Carbon Metallurgical Innovation Foundation(2022)2023 Anhui Major Industrial Innovation Plan Project。
文摘The in-flight heating process of cerium dioxide(CeO_(2))powders was investigated through experiments and numerical simulations.In the experiment,CeO_(2)powder(average size of 30μm)was injected into radio-frequency(RF)argon plasma,and the temperatures were measured using a DPV-2000 monitor.A model combining the electromagnetism,thermal flow,and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed.The melting processes of CeO_(2)powders of different diameters,with and without thermal resistance effect,were investigated.Results show that the heating process of CeO_(2)powder particles consists of three main stages,one of which is relevant to a dimensionless parameter known as the Biot number.When the Biot value≥0.1,thermal resistance increases significantly,especially for the larger powders.The predicted temperature of the particles at the outlet(1800–2880 K)is in good agreement with the experimental result.
文摘CZTS(Cu_(2)ZnSnS_(4))is a quaternary semiconductor that is environmentally friendly,less expensive.In this paper,we report on the optimization and fabrication of CZTS-based heterojunction nanodevices for bifunctional applications such as solar cells and photodetectors.CZTS thin films were deposited on top of(Molybdenum)Mo-coated glass substrates via RF sputtering at 100 and 200 W.Rapid thermal processing(RTP)was used at 300,400,and 500℃temperatures.Cd S(cadmium sulphide)was deposited on CZTS using a chemical bath deposition system with 3-and 5-min deposition times.Zn O(zinc oxide)and AZO(aluminium doped zinc oxide)layers were deposited using RF(radio frequency)sputtering to create the solar device.XRD confirms the formation of a tetragonal structure with increased crystallinity due to the use of RTP.Raman reveals the characteristic Raman shift peak associated with CZTS at 336 and 335 cm^(-1).The FESEM shows a relationship with RTP temperature.Surface features,including grain size,vary with RTP temperature.The ideality factor is nearly 2,indicating imperfection in the Mo/CZTS interface.Schottky barrier height estimates range from 0.6 to 0.7 e V.Absorbance and transmittance show a predictable fluctuation with RTP temperature.Photovoltaic device was built using the higher crystalline feature of CZTS in conjunction with Cd S deposited at 3 and 5 min.The efficiency of Cd S deposited after 3 and 5 min was 1.15 and 0.97 percent,respectively.Fabricated devices were used for wavelength-dependent photodetection.This work demonstrated self-powered photodetection.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515140007).
文摘In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of copper strips connected to a capacitor at either end,is typically employed as a vacuum chamber to mitigate eddy current effects and beam coupling impedance.Consequently,the ceramic chamber exhibits a thin-walled multilayered complex structure.Previous theoretical studies have suggested that the impedance of such a structure has a negligible impact on the beam.However,recent impedance measurements of the ceramic chamber in the China Spallation Neutron Source(CSNS)RCS revealed a resonance in the low-frequency range,which was confirmed by further theoretical analysis as a source of beam instability in the RCS.Currently,the magnitude of this impedance cannot be accurately assessed using theoretical calculations.In this study,we used the CST Microwave Studio to confirm the impedance of the ceramic chamber.Further simulations covering six different types of ceramic chambers were conducted to develop an impedance model in the RCS.Additionally,this study investigates the resonant characteristics of the ceramic chamber impedance,finding that the resonant frequency is closely related to the capacitance of the capacitors.This finding provides clear directions for further impedance optimization and is crucial for achieving a beam power of 500 kW for the CSNS Phase-Ⅱ project(CSNS-Ⅱ).However,careful attention must be paid to the voltage across the capacitors.
文摘Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for maritime rockets.The suggested approach introduces a hybrid model that combines random forest(RF)and Adaptive boosting(Ada Boost)methods to describe the coupling mechanism of factors affecting rocket rolling and to suppress the rolling.This combination improves forecast accuracy.Thereafter,the dimensionality reduced response surfaces are used to visually present the coupling between rocket rolling and influencing factors,which reveals the prelaunch rolling mechanism.When angle between the launch device and the ship's bow is within 80°-100°,the dynamic friction coefficient between adapters and guideways is 0.4,and the dynamic friction coefficient between the rocket and launchpad is within 0-0.15 or0.5-0.7,the prelaunch rolling of rocket during one motion cycle of the ship is less than 0.065°,originally 0.27°,reduced by 75.93%,effectively suppressing the prelaunch rolling.This study improves the prelaunch stability of maritime rockets in rough sea conditions and establishes a mapping relationship between the factors affecting rocket rolling and the structure of the sea launch system,guiding the optimization of future sea launch systems.
