The Cu_(65)Ni_(35) alloy liquid was undercooled by the fluxing method,and the rapid solidification structure was obtained by natural cooling.The solidification interface migration information of Cu_(65)Ni_(35) alloy l...The Cu_(65)Ni_(35) alloy liquid was undercooled by the fluxing method,and the rapid solidification structure was obtained by natural cooling.The solidification interface migration information of Cu_(65)Ni_(35) alloy liquid in rapid solidification stage was photographed with the help of high-speed camera,and the recalescence velocity was calculated.The microstructure evolution of the alloy was systematically studied by observing the microstructure morphology and taking photos on the metallographic microscope.By analyzing the evolution of dendrite grain size and microstructure microhardness with undercoolingand relying on electron backscatter diffraction(EBSD)technology,the grain refinement mechanism of microstructure under high undercooling and low undercooling is finally confirmed.展开更多
A flower-like SnO_(2)–SnO/porous Ga N(FSS/PGaN) heterojunction was fabricated for the first time via a facile spraying process, and the whole process also involved hydrothermal preparation of FSS and electrochemical ...A flower-like SnO_(2)–SnO/porous Ga N(FSS/PGaN) heterojunction was fabricated for the first time via a facile spraying process, and the whole process also involved hydrothermal preparation of FSS and electrochemical wet etching of GaN,and SnO_(2)–SnO composites with p–n junctions were loaded onto PGaN surface directly applied to H_(2)S sensor. Meanwhile,the excellent transport capability of heterojunction between FSS and PGaN facilitates electron transfer, that is, a response time as short as 65 s and a release time up to 27 s can be achieved merely at 150℃ under 50 ppm H_(2)S concentration, which has laid a reasonable theoretical and experimental foundation for the subsequent PGaN-based heterojunction gas sensor.The lowering working temperature and high sensitivity(23.5 at 200 ppm H2S) are attributed to the structure of PGaN itself and the heterojunction between SnO_(2)–SnO and PGaN. In addition, the as-obtained sensor showed ultra-high test stability.The simple design strategy of FSS/PGaN-based H_(2)S sensor highlights its potential in various applications.展开更多
通过对文件传输协议(file transfer protocol,FTP)的研究,提出一种FTP协议信息隐藏方法。通过将特定目录编码,将秘密信息嵌入正常的更改工作目录命令(change working directory,CWD)实现隐蔽通信。对比已有的几种FTP隐蔽信道,对其隐蔽...通过对文件传输协议(file transfer protocol,FTP)的研究,提出一种FTP协议信息隐藏方法。通过将特定目录编码,将秘密信息嵌入正常的更改工作目录命令(change working directory,CWD)实现隐蔽通信。对比已有的几种FTP隐蔽信道,对其隐蔽性、鲁棒性和容量进行分析,该隐蔽信道在隐蔽性和鲁棒性相同的情况下,通过适当编码大幅提高单条命令的隐藏容量,在编码数目大于一定值时,隐藏容量将高于目前已有的几种FTP隐蔽信道。实验结果验证了该方法的可行性。展开更多
基金Funded by the National Natural Science Foundation of China(No.51701187)the Basic Applied Research Projects in Shanxi Province(201801D221151)。
文摘The Cu_(65)Ni_(35) alloy liquid was undercooled by the fluxing method,and the rapid solidification structure was obtained by natural cooling.The solidification interface migration information of Cu_(65)Ni_(35) alloy liquid in rapid solidification stage was photographed with the help of high-speed camera,and the recalescence velocity was calculated.The microstructure evolution of the alloy was systematically studied by observing the microstructure morphology and taking photos on the metallographic microscope.By analyzing the evolution of dendrite grain size and microstructure microhardness with undercoolingand relying on electron backscatter diffraction(EBSD)technology,the grain refinement mechanism of microstructure under high undercooling and low undercooling is finally confirmed.
基金supported by the Australian Research Council(FT190100636 and DP190103472)supported by computational resources provided by the Australian Government through NCI under the National Computational Merit Allocation Schemethe Phoenix High Performance Compute(HPC)Service at The University of Adelaide。
基金financially supported by the National Natural Science Foundation of China(No.52171114)the Innovation-oriented Advanced Technology and Industrial Technology Program Project of Hunan Province,China(No.2020SK2017)。
基金supported by the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications (Grant Nos. XK1060921115 and XK1060921002)Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 62204125)+1 种基金the National Key R&D Program of China (Grant No. 2022YFB3605404)the Natural Science Foundation of Guangdong Province, China (Grant No. 2019A1515010790)。
文摘A flower-like SnO_(2)–SnO/porous Ga N(FSS/PGaN) heterojunction was fabricated for the first time via a facile spraying process, and the whole process also involved hydrothermal preparation of FSS and electrochemical wet etching of GaN,and SnO_(2)–SnO composites with p–n junctions were loaded onto PGaN surface directly applied to H_(2)S sensor. Meanwhile,the excellent transport capability of heterojunction between FSS and PGaN facilitates electron transfer, that is, a response time as short as 65 s and a release time up to 27 s can be achieved merely at 150℃ under 50 ppm H_(2)S concentration, which has laid a reasonable theoretical and experimental foundation for the subsequent PGaN-based heterojunction gas sensor.The lowering working temperature and high sensitivity(23.5 at 200 ppm H2S) are attributed to the structure of PGaN itself and the heterojunction between SnO_(2)–SnO and PGaN. In addition, the as-obtained sensor showed ultra-high test stability.The simple design strategy of FSS/PGaN-based H_(2)S sensor highlights its potential in various applications.
文摘通过对文件传输协议(file transfer protocol,FTP)的研究,提出一种FTP协议信息隐藏方法。通过将特定目录编码,将秘密信息嵌入正常的更改工作目录命令(change working directory,CWD)实现隐蔽通信。对比已有的几种FTP隐蔽信道,对其隐蔽性、鲁棒性和容量进行分析,该隐蔽信道在隐蔽性和鲁棒性相同的情况下,通过适当编码大幅提高单条命令的隐藏容量,在编码数目大于一定值时,隐藏容量将高于目前已有的几种FTP隐蔽信道。实验结果验证了该方法的可行性。
