| 1 | High-speed maneuvering target detection approach based on joint RFT and keystone transform显示文摘Increasing the integration time is an effective method to improve small maneuvering target detection performance in radar applications.However,range migration and Doppler spread caused by maneuvering target motion during the integration time make it difficult to improve the coherent accumulation of target's energy and detection performance.In this study,a new method based on Radon Fourier transform(RFT) and keystone transform(KT) for high-speed maneuvering target detection is proposed.The proposed algorithm utilizes second-order KT to correct the range curvature,and the improved dechirping method to compensate for the Doppler spread.RFT is then used to correct the range walk for target coherent detection.The method is capable of correcting the range migration and the time-varied Doppler frequency of the target without knowing its velocity and acceleration.The advantage of the proposed method is that it can increase the coherent integration time and improve detection performance under the condition of Doppler frequency ambiguity.Compared with the second-order RFT algorithm,the computational burden of the proposed method is greatly reduced under the premise that the two methods have similar estimation accuracy of range,velocity and acceleration.Numerical experiments demonstrate the validity of the proposed algorithm. | TIAN Jing CUI Wei SHEN Qing WEI ZiXiang WU SiLiang | 2013 | Science China(Information Sciences)2013，56，6： | 19 |
| 2 | Effects of shape and particle size on the photocatalytic kinetics and mechanism of nano-CeO_(2)显示文摘Nanomaterials have been widely applied to many fields because of their excellent photocatalytic performance.The performance is closely related to the catalytic kinetics,but it is not completely clear about the influencing regularities of shape and particle size on the photocatalytic kinetics of nanomaterials and the photocatalytic kinetic mechanism.In this paper,nano-CeO_(2)with different shapes and particle sizes were prepared,the kinetic parameters of adsorption and photocatalytic degradation were determined,and the effects of shape and particle size on the kinetics of adsorption and photocatalysis and photocatalytic mechanism were discussed.The results show that the shape and particle size have significant influences.With the decreases of diameter,the performances of adsorption and photocatalysis of nano-CeO_(2)are improved;and these performances of spherical nano-CeO_(2)are greater than those of linear nano-CeO_(2).The shape and particle size have no effects on the kinetic order and mechanism of the whole photocatalytic process.Then a generalized mechanism of photocatalytic kinetics of nanomaterials was proposed and the mechanism rate equation was derived.Finally,the conclusion can be drawn:the desorption of photodegradation products is the control step of photocatalytic kinetics,and the kinetic order of photocatalytic degradation reaction is 1.The mechanism is universal and all nanomaterials have the same photocatalytic kinetic mechanism and order. | Zixiang Cui Lu Zhang Yongqiang Xue Ya’nan Feng Mengying Wang Jiaojiao Chen Boteng Ji Chenyu Wang Yidi Xue | 2022 | International Journal of Minerals,Metallurgy and Materials2022，29，12： | 1 |
| 3 | Bifunctional oxygen electrocatalysts for rechargeable zinc-air battery based on MXene and beyond显示文摘Oxygen electrocatalysts are of great importance for the air electrode in zinc–air batteries(ZABs).Owing to large surface area,high electrical conductivity and ease of modification,two-dimensional(2D)materials have been widely studied as oxygen electrocatalysts for the rechargable ZABs.The elaborately modified 2D materials-based electrocatalysts,usually exhibit excellent performance toward the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),which have attracted extensive interests of worldwide researchers.Given the rapid development of bifunctional electrocatalysts toward ORR and OER,the latest progress of non-noble electrocatalysts based on layered double hydroxides(LDHs),graphene,and MXenes are intensively reviewed.The discussion ranges from fundamental structure,synthesis,electrocatalytic performance of these catalysts,as well as their applications in the rechargeable ZABs.Finally,the challenges and outlook are provided for further advancing the commercialization of rechargeable ZABs. | Jing Zhang Zixiang Cui Jie Liu Chunjie Li Haoyi Tan Guangcun Shan Ruguang Ma | 2023 | Frontiers of physics2023，18，1： | 1 |
| 4 | Investigation on the radioactivity levels of seawater,sediments,and biota in Daya Bay,China显示文摘Objective:To investigate the radioactivity levels of seawater,sediments,and biota in the Daya Bay sea area,China,in order to establish the radioactivity baseline values,and provide basic data for the assessment of potential radiological risks that might result from the application of nuclear technology or human activities.Methods:Samples of seawater,sediments,and biota were collected from the Daya Bay sea area and analyzed.Their radioactivity baseline data were then compared with information from other regions in China and around the world reported in related literature.Results:For the seawater samples,the activity concentrations of natural radionuclide ^(40)K were 9.9-10.4 Bq/L,while ^(238)U,226Ra,^(210)Pb,^(137)Cs,and ^(110)Ag^(m) were below the minimum detectable activity(MDA).Regarding the sediment samples,the activity concentrations of ^(238)U,^(228)Ra,^(226)Ra,^(210)Pb,^(40)K,and ^(137)Cs were 38.1-40.4,49.1-53.7,32.6-38.6,59-95,590-650,and 0.48-0.88 Bq/(kg dry weight),respectively,while ^(110)Agm was below the MDA.For the marine shrimps in the biota samples,the activity concentrations of ^(228)Ra,^(226)Ra,^(40)K,and ^(137)Cs were 1.14-2.75,0.17-0.43,63-76,and 0.038-0.045 Bq/(kg wet weight),respectively,while ^(238)U,^(210)Pb,and ^(110)Agm were all below the MDA.Furthermore,for the marine fishes in the biota samples,the activity concentrations of ^(228)Ra,^(226)Ra,^(210)Pb,^(40)K,and ^(137)Cs were 2.1-19.7,0.32-3.78,<2.2-2.8,59-70,and<0.007-0.026 Bq/(kg wet weight),respectively,while ^(238)U and ^(110)Ag^(m) were all below the MDA.^(228)Ra was found to be concentrated in Osteomugil ophuyseni with 19.7 Bq/(kg wet weight).Conclusions:The radioactivity levels of seawater and marine sediments in the Daya Bay sea area are within the range of the normal background values.Osteomugil ophuyseni exhibited higher concentrations of ^(228)Ra than other species in this study,while the other species in the biota show no significant difference in the radioactivity levels from data in relevant literature. | Fan Cui Honghui Huang Yi Shen Zhan Tan Pengxiang Qu Ming Dai Hongwei Yu Weixu Huang Zixiang Wu Huifeng Chen Weizhen Guo Yuxin Jia Yanbing Liu | 2023 | Radiation Medicine and Protection2023，4，3： | 0 |
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