The concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence are researched, the mapping relationship between quick trickle characteristic sequen...The concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence are researched, the mapping relationship between quick trickle characteristic sequence and quick trickle permutation is discussed. Finally, an efficient construction of quick trickle permutation based on quick trickle characteristic sequence is given, by which quick trickle permutation can be figured out after constructing quick trickle characteristic sequence. Quick trickle permutation has good cryptographic properties.展开更多
[ Objective] The study aimed to discuss analyze climate change characteristics and return periods of heavy precipitation in the northeast side of Qinghai-Tibet Plateau. [ Method] Based on the data of daily precipitati...[ Objective] The study aimed to discuss analyze climate change characteristics and return periods of heavy precipitation in the northeast side of Qinghai-Tibet Plateau. [ Method] Based on the data of daily precipitation from 1943 to 2008 in 6 representative meteorological stations in Linxia located in the northeast side of Qinghai-Tibet Plateau, the climate change characteristics of heavy precipitation were analyzed, and the return periods of heavy precipitation were calculated by Pearson-Ill probability distribution method. [ Result] Days of heavy precipitation in Linxia region in- creased conspicuously since the 1990s. The return periods of heavy precipitation in the six stations on August 20, 2008 were consistent with the re- sults of artificial estimation. [ Conclusion] The research could provide scientific references for the reasonable utilization of climate resources, disas- ter prevention and rational arranqement of anricultural plantina svstems in Linxia reaion.展开更多
In the North China Plain(NCP), soil deterioration threatens winter wheat(Triticum aestivum L.) production. Although rotary tillage or plowing tillage are two methods commonly used in this region, research characterizi...In the North China Plain(NCP), soil deterioration threatens winter wheat(Triticum aestivum L.) production. Although rotary tillage or plowing tillage are two methods commonly used in this region, research characterizing the effects of mixed tillage on soil characteristics and wheat yield has been limited. A fixed-site field trial was carried out during 2011–2016 to examine the impacts of three tillage practices(5-year rotary tillage with maize straw removal(RT);5-year rotary tillage with maize straw return(RS);and annual RS and with a deep plowing interval of 2 years(RS/DS)) on soil characteristics and root distribution in the plough layer. Straw return significantly decreased soil bulk density, increased soil organic carbon(SOC) storage and SOC content, macro-aggregate proportion(R_(0.25)) and its stability in the plough layer. The RS/DS treatment significantly increased the SOC content, total nitrogen(TN), and root length density(RLD) in the 10–40 cm layer, and enhanced the proportion of RLD in the 20–30 and 30–40 cm layers. In the 20–30 and 30–40 cm layers, an increase in SOC and TN could lead to higher grain production than commensurate increases in the surface layer, resulting in a sustainable increase in grain yield from the RS/DS treatment. Thus, the RS/DS treatment could lead to high productivity of winter wheat by improving soil characteristics and root distribution at the deeper plough layer in the NCP.展开更多
We establish a simulation model based on the theory of air flow to analyze the accelerated release effect of the quick release valve inside the air brake control valve.In addition, the combined simulation system of tr...We establish a simulation model based on the theory of air flow to analyze the accelerated release effect of the quick release valve inside the air brake control valve.In addition, the combined simulation system of train air brake system and longitudinal train dynamics is used to analyze how the parameters of the quick release valve in the 120/120–1 brake control valve affect the propagation characteristics of the train brake pipe pressure wave, the release action range of the accelerated brake, and the longitudinal coupler force for a 20,000-ton heavy haul train on the section of the Datong–Qinhuangdao Railway. The results show that the quick release valve can effectively accelerate the rising speed of the train brake pipe pressure during the initial release, as the accelerated release effect is evident before the train brake pipe pressure reaches582 k Pa. The quick release valve can effectively accelerate the release of the rear cars, reducing the longitudinal coupler force impact due to time delay of the release process. The quick release valve can effectively reduce the tensile coupler force in the train by as much as 20% in certain cases.展开更多
The galvanic-coupled intrabody communication(GCIBC)uses the human body as the channel for data transmission.The signal flow through different paths within different measure-ment schemes,resulting in distinct deviation...The galvanic-coupled intrabody communication(GCIBC)uses the human body as the channel for data transmission.The signal flow through different paths within different measure-ment schemes,resulting in distinct deviations in the experimental results.This method completely uses human body channel to transmit low-power signals,and has good anti-interference perform-ance.However,for a long time,the channel research of GCIBC has not determined a set of recog-nized and accurate measurement methods and standards.However,few researcher analyze the dif-ferences and principles between different measurement methods.This paper aims at three com-monly used measurement methods.Abstract the equivalent schematic diagrams of three measure-ment schemes:direct measurement,using high-precision differential probe and using balun.The sig-nal return paths generated by three measurement methods are analyzed,the impedance matching and energy transmission efficiency are compared.According to the analysis,the empirical expres-sions in different cases are listed.The mechanism between the channel measurement results gener-ated by the set experimental configuration and the comparison experiment is clarified.The compar-ison experiment with complete floating measurement is carried out as a reference to verify the pro-posed opinion.The measurement error caused by different experimental configurations is verified.This study can provide a reference opinions for the experimental error analysis of GCIBC research in the future,and provide suggestions for the selection of experimental configuration.展开更多
文摘The concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence are researched, the mapping relationship between quick trickle characteristic sequence and quick trickle permutation is discussed. Finally, an efficient construction of quick trickle permutation based on quick trickle characteristic sequence is given, by which quick trickle permutation can be figured out after constructing quick trickle characteristic sequence. Quick trickle permutation has good cryptographic properties.
基金Supported by the Science and Technology Research Projects of Gansu Meteorological Bureau(2013-14)
文摘[ Objective] The study aimed to discuss analyze climate change characteristics and return periods of heavy precipitation in the northeast side of Qinghai-Tibet Plateau. [ Method] Based on the data of daily precipitation from 1943 to 2008 in 6 representative meteorological stations in Linxia located in the northeast side of Qinghai-Tibet Plateau, the climate change characteristics of heavy precipitation were analyzed, and the return periods of heavy precipitation were calculated by Pearson-Ill probability distribution method. [ Result] Days of heavy precipitation in Linxia region in- creased conspicuously since the 1990s. The return periods of heavy precipitation in the six stations on August 20, 2008 were consistent with the re- sults of artificial estimation. [ Conclusion] The research could provide scientific references for the reasonable utilization of climate resources, disas- ter prevention and rational arranqement of anricultural plantina svstems in Linxia reaion.
基金supported by the National Basic Research Program of China(973 Program2015CB150404)+1 种基金the National Key Research and Development Program of China(2017YFD0301001 and 2016YFD0300403)the Shandong Province Mount Tai Industrial Talents Program,China。
文摘In the North China Plain(NCP), soil deterioration threatens winter wheat(Triticum aestivum L.) production. Although rotary tillage or plowing tillage are two methods commonly used in this region, research characterizing the effects of mixed tillage on soil characteristics and wheat yield has been limited. A fixed-site field trial was carried out during 2011–2016 to examine the impacts of three tillage practices(5-year rotary tillage with maize straw removal(RT);5-year rotary tillage with maize straw return(RS);and annual RS and with a deep plowing interval of 2 years(RS/DS)) on soil characteristics and root distribution in the plough layer. Straw return significantly decreased soil bulk density, increased soil organic carbon(SOC) storage and SOC content, macro-aggregate proportion(R_(0.25)) and its stability in the plough layer. The RS/DS treatment significantly increased the SOC content, total nitrogen(TN), and root length density(RLD) in the 10–40 cm layer, and enhanced the proportion of RLD in the 20–30 and 30–40 cm layers. In the 20–30 and 30–40 cm layers, an increase in SOC and TN could lead to higher grain production than commensurate increases in the surface layer, resulting in a sustainable increase in grain yield from the RS/DS treatment. Thus, the RS/DS treatment could lead to high productivity of winter wheat by improving soil characteristics and root distribution at the deeper plough layer in the NCP.
基金China National Railway Group Co.,Ltd(N2020J037).
文摘We establish a simulation model based on the theory of air flow to analyze the accelerated release effect of the quick release valve inside the air brake control valve.In addition, the combined simulation system of train air brake system and longitudinal train dynamics is used to analyze how the parameters of the quick release valve in the 120/120–1 brake control valve affect the propagation characteristics of the train brake pipe pressure wave, the release action range of the accelerated brake, and the longitudinal coupler force for a 20,000-ton heavy haul train on the section of the Datong–Qinhuangdao Railway. The results show that the quick release valve can effectively accelerate the rising speed of the train brake pipe pressure during the initial release, as the accelerated release effect is evident before the train brake pipe pressure reaches582 k Pa. The quick release valve can effectively accelerate the release of the rear cars, reducing the longitudinal coupler force impact due to time delay of the release process. The quick release valve can effectively reduce the tensile coupler force in the train by as much as 20% in certain cases.
基金the National Natural Science Found-ation of China(No.U1505251)the International Coopera-tion Project in Fujian Province(No.2021I0005)Project of Education Department of Fujian Province(No.JAT200051).
文摘The galvanic-coupled intrabody communication(GCIBC)uses the human body as the channel for data transmission.The signal flow through different paths within different measure-ment schemes,resulting in distinct deviations in the experimental results.This method completely uses human body channel to transmit low-power signals,and has good anti-interference perform-ance.However,for a long time,the channel research of GCIBC has not determined a set of recog-nized and accurate measurement methods and standards.However,few researcher analyze the dif-ferences and principles between different measurement methods.This paper aims at three com-monly used measurement methods.Abstract the equivalent schematic diagrams of three measure-ment schemes:direct measurement,using high-precision differential probe and using balun.The sig-nal return paths generated by three measurement methods are analyzed,the impedance matching and energy transmission efficiency are compared.According to the analysis,the empirical expres-sions in different cases are listed.The mechanism between the channel measurement results gener-ated by the set experimental configuration and the comparison experiment is clarified.The compar-ison experiment with complete floating measurement is carried out as a reference to verify the pro-posed opinion.The measurement error caused by different experimental configurations is verified.This study can provide a reference opinions for the experimental error analysis of GCIBC research in the future,and provide suggestions for the selection of experimental configuration.
