The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(...The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(ETF)is located in the main ring of the HIRFL-CSR.The gamma detector of the ETF is built to measure emitted gamma rays with energies below 5 MeV in the center-of-mass frame and is planned to measure light fragments with energies up to 300 MeV.The readout electronics for the gamma detector were designed and commissioned.The readout electronics consist of thirty-two front-end cards,thirty-two readout control units(RCUs),one common readout unit,one synchronization&clock unit,and one sub-trigger unit.By using the real-time peak-detection algorithm implemented in the RCU,the data volume can be significantly reduced.In addition,trigger logic selection algorithms are implemented to improve the selection of useful events and reduce the data size.The test results show that the integral nonlinearity of the readout electronics is less than 1%,and the energy resolution for measuring the 60 Co source is better than 5.5%.This study discusses the design and performance of the readout electronics.展开更多
We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FA...We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FAPbI_3) by using the material studio. By using the first-principles calculations, the energy band structure, density of states(DOS), and partial DOS(PDOS) of the hydrazine-iodide lead halide are obtained. Then, we theoretically analyze a design scheme for perovskite solar cell materials, published in [Science 354, 861(2016)], with the photoelectric conversion efficiency that can reach 20.3%. Also, we use non-toxic elements to replace lead in FAPbI_3 without affecting its photoelectric conversion efficiency. Here in this work, we explore the energy band structure, lattice constant, light absorption efficiency, etc. After the Ca, Zn, Ge Sr, Sn, and Ta atoms replacing lead(Pb) and through comparing the spectral distributions of the solar spectrum, it can be found that FAGeI_3, FASnI_3, and FAZnI_3 have better absorbance characteristics in the solar spectrum range. If the band gap structure is taken into account, FAGeI_3 will become an ideal material to replace FAPbI_3, although its performance is slightly lower than that of FAPbI_3. The toxicity of Pb is taken into account, and the Ge element can be used as a substitute element for Pb. Furthermore, we explore one of the perovskite materials, i.e., FA0.75Cs_(0.25)Sn_(0.25)Ge_(0.75)I_3 whose photovoltaic properties are close to those of FA_(0.75)Cs_(0.25)Sn_(0.5)Pb_(0.5)I_3, but the former does not contain toxic atoms.Our results pave the way for further investigating the applications of these materials in relevant technologies.展开更多
Dislocations and other atomic-level defects play a crucial role in determining the macroscopic properties of crystalline materials,but it is extremely difficult to observe the evolution of dislocations due to the limi...Dislocations and other atomic-level defects play a crucial role in determining the macroscopic properties of crystalline materials,but it is extremely difficult to observe the evolution of dislocations due to the limitations of the most advanced experimental techniques.Therefore,in this work,the rapid solidification processes of Ni_(47)Co_(53) alloy at five cooling rates are studied by molecular dynamics simulation,and the evolutions of their microstructures and dislocations are investigated as well.The results show that face-centered cubic(FCC) structures are formed at the low cooling rate,and the crystalline and amorphous mixture appear at the critical cooling rate,and the amorphous are generated at the high cooling rate.The crystallization temperature and crystallinity decrease with cooling rate increasing.Dislocations are few at the cooling rates of 1×10^(11) K/s,5×10^(12) K/s,and 1×10^(13) K/s,and they are most abundant at the cooling rates of 5×10^(11) K/s and1 × 10^(12) K/s,in which their dislocation line lengths are both almost identical.There appear a large number of dislocation reactions at both cooling rates,in which the interconversion between perfect and partial dislocations is primary.The dislocation reactions are more intense at the cooling rate of 5×10^(11) K/s,and the slip of some dislocations leads to the interconversion between FCC structure and hexagonal close packed(HCP) structure,which causes the twin boundaries(TBs) to disappear.The FCC and HCP are in the same atomic layer,and dislocations are formed at the junction due to the existence of TBs at the cooling rate of 1 ×10^(12) K/s.The present research is important in understanding the dislocation mechanism and its influence on crystal structure at atomic scales.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 12222512, 12375193, U2031206, U1831206, and U2032209)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (GJJSTD20210009)+1 种基金the CAS Pioneer Hundred Talent Programthe CAS Light of West China Program
文摘The Cooling Storage Ring of the Heavy Ion Research Facility in Lanzhou(HIRFL-CSR)was constructed to study nuclear physics,atomic physics,interdisciplinary science,and related applications.The External Target Facility(ETF)is located in the main ring of the HIRFL-CSR.The gamma detector of the ETF is built to measure emitted gamma rays with energies below 5 MeV in the center-of-mass frame and is planned to measure light fragments with energies up to 300 MeV.The readout electronics for the gamma detector were designed and commissioned.The readout electronics consist of thirty-two front-end cards,thirty-two readout control units(RCUs),one common readout unit,one synchronization&clock unit,and one sub-trigger unit.By using the real-time peak-detection algorithm implemented in the RCU,the data volume can be significantly reduced.In addition,trigger logic selection algorithms are implemented to improve the selection of useful events and reduce the data size.The test results show that the integral nonlinearity of the readout electronics is less than 1%,and the energy resolution for measuring the 60 Co source is better than 5.5%.This study discusses the design and performance of the readout electronics.
基金Project supported by the National Natural Science Foundation of China(Grant No.11164004)the Industrial Research Project of Guizhou Province,China(Grant No.GY[2012]3060)+1 种基金the Project of Education Department of Guizhou Province,China(Grant No.[2016]215)the Special Laboratory Fund of Education Department of Guizhou Province,China(Grant No.GY[2014]217)
文摘We have discussed the materials of solar cell based on hybrid organic–inorganic halide perovskites with formamidinium(NH_2CH = NH_2^+or FA) lead iodide. Firstly, we build the structure of formamidinium lead iodide(FAPbI_3) by using the material studio. By using the first-principles calculations, the energy band structure, density of states(DOS), and partial DOS(PDOS) of the hydrazine-iodide lead halide are obtained. Then, we theoretically analyze a design scheme for perovskite solar cell materials, published in [Science 354, 861(2016)], with the photoelectric conversion efficiency that can reach 20.3%. Also, we use non-toxic elements to replace lead in FAPbI_3 without affecting its photoelectric conversion efficiency. Here in this work, we explore the energy band structure, lattice constant, light absorption efficiency, etc. After the Ca, Zn, Ge Sr, Sn, and Ta atoms replacing lead(Pb) and through comparing the spectral distributions of the solar spectrum, it can be found that FAGeI_3, FASnI_3, and FAZnI_3 have better absorbance characteristics in the solar spectrum range. If the band gap structure is taken into account, FAGeI_3 will become an ideal material to replace FAPbI_3, although its performance is slightly lower than that of FAPbI_3. The toxicity of Pb is taken into account, and the Ge element can be used as a substitute element for Pb. Furthermore, we explore one of the perovskite materials, i.e., FA0.75Cs_(0.25)Sn_(0.25)Ge_(0.75)I_3 whose photovoltaic properties are close to those of FA_(0.75)Cs_(0.25)Sn_(0.5)Pb_(0.5)I_3, but the former does not contain toxic atoms.Our results pave the way for further investigating the applications of these materials in relevant technologies.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11964005, 11963003, and 62163006)the Fostering Project of Guizhou University, China (Grant Nos. [2020]33 and [2020]76)+1 种基金the Basic Research Program of Guizhou Province, China (Grant Nos. ZK[2022] 042 and ZK[2022] 143)the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University, China (Grant No. 2020-520000-83-01-324061)。
文摘Dislocations and other atomic-level defects play a crucial role in determining the macroscopic properties of crystalline materials,but it is extremely difficult to observe the evolution of dislocations due to the limitations of the most advanced experimental techniques.Therefore,in this work,the rapid solidification processes of Ni_(47)Co_(53) alloy at five cooling rates are studied by molecular dynamics simulation,and the evolutions of their microstructures and dislocations are investigated as well.The results show that face-centered cubic(FCC) structures are formed at the low cooling rate,and the crystalline and amorphous mixture appear at the critical cooling rate,and the amorphous are generated at the high cooling rate.The crystallization temperature and crystallinity decrease with cooling rate increasing.Dislocations are few at the cooling rates of 1×10^(11) K/s,5×10^(12) K/s,and 1×10^(13) K/s,and they are most abundant at the cooling rates of 5×10^(11) K/s and1 × 10^(12) K/s,in which their dislocation line lengths are both almost identical.There appear a large number of dislocation reactions at both cooling rates,in which the interconversion between perfect and partial dislocations is primary.The dislocation reactions are more intense at the cooling rate of 5×10^(11) K/s,and the slip of some dislocations leads to the interconversion between FCC structure and hexagonal close packed(HCP) structure,which causes the twin boundaries(TBs) to disappear.The FCC and HCP are in the same atomic layer,and dislocations are formed at the junction due to the existence of TBs at the cooling rate of 1 ×10^(12) K/s.The present research is important in understanding the dislocation mechanism and its influence on crystal structure at atomic scales.
