An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were ...An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were empty and a total of 628 looks plump. Soft X ray radiographs showed that, still and all, a majority of the “plump" seeds were embryoless (597, 95.6%) whereas some were partially developed (17,2.7%) and only a few were really full (14, 2.2%). 2. Germination test showed that all of the radiographed hybrid seeds with fully developed embryos were germinable whereas those with partially developed embryos were ungerminable. 3. Physiologically, the growth rate of hypocotyl, the date for shedding of seed coat and spreading of cotyledons, the elongation of epicotyl, and the branching of shoot of the 11 month old seedlings showed a tendency to fall behind those of the female parent; morphologically, the 11 month old hybrid seedlings with linear leaves appeared rather short, slender and weak, whereas the seedlings of the female parents with linear_lanceolate leaves appeared rather tall, stout and strong. 4. It is considered that the hybrid may be true and the crossability reveals a close phylogenetic affinity of Cunninghamia with Cryptomeria.展开更多
The low altitude airspace will be open in China, general aviation flights are tremendously increased. Whether aircrafts can fly safely and how to determine the requirements of safety flight are the problems needed to ...The low altitude airspace will be open in China, general aviation flights are tremendously increased. Whether aircrafts can fly safely and how to determine the requirements of safety flight are the problems needed to be confirmed. Under this circumstances, based on the international Civil Aviation Organization（ICAO） criteria and the standards made by CAAC, this paper adopts the ＂See and Avoid＂ principle. Under the binding conditions of flight rules, visibility requirements, responding time, the aircraft speed, circle banking angle or the climbing angle, based on its study on aircraft dynamics principles, this paper establishes a mathematical collision avoidance model for head-to-head traffic and crossing converging traffic at the same level. And the safety separation requirements of the aircrafts in low altitude flight are equantitatively analyzed. Finally, the Matlab software is used to analyze the above method. The result shows that the safe traffic avoidance of the converging traffic at the same level meets certain flight conditions, while intersecting the traffic at the same level can safely avoid the collision.展开更多
In the study and implementation of a programmable RS codec module in satellite communication modem, FPGA is used as the kernel in the implementation, while some ASICs are used as necessary assistant measures. The modu...In the study and implementation of a programmable RS codec module in satellite communication modem, FPGA is used as the kernel in the implementation, while some ASICs are used as necessary assistant measures. The module includes the RS codec unit, the interleaver and deinterleaver unit, the scrambler and descrambler unit and the frame synchronization unit. The module is realized successfully and it can be programmed on-line to meet the requirements of IESS 308/309/310 including many specifications about different service types and data rates. With the implementation combining FPGA with ASICs, size of the circuit is much reduced, its flexibility dramatically increased, and its stability further strengthened. Furthermore, the module is based on the software radio concept and can be easily integrated into the whole satellite communication modem.展开更多
The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array de...The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array design（OAD） is used and factors such as SBS modifier content,storage time,storage temperature and container size are chosen in a mixed-level OAD with an OA16（31×44） matrix.Parameters like the separation softening point difference（the separation difference of the ring and ball softening point of the top and bottom samples） and the average softening point（the arithmetic mean of the softening points of the top and bottom samples） are proposed to evaluate the separation and the ageing of modified bitumen during storage in this experiment,respectively.The results reveal that the separation and the ageing during storage exhibit a complicated variation for storage temperature and time.The separation softening point difference decreases with the storage temperature rising from 20 to 120 ℃ and increases with the temperature exceeding 120 ℃,and the average softening point drops with the storage time being prolonged.Different storage conditions have various effects on the storage stability of SBS modified bitumen.展开更多
Excavation-induced microseismicity and rockburst occurrence in deep underground projects provide invaluable information that can be used to warn rockburst occurrence,facilitate rockburst mitigation procedures,and anal...Excavation-induced microseismicity and rockburst occurrence in deep underground projects provide invaluable information that can be used to warn rockburst occurrence,facilitate rockburst mitigation procedures,and analyze the mechanisms responsible for their occurrence.Based on the deep parallel tunnels with the maximum depth of 1890 m created as part of the Neelum–Jhelum hydropower project in Pakistan,similarities and differences on excavation-induced microseismicity and rockburst occurrence between parallel tunnels with soft and hard alternant strata are studied.Results show that a large number of microseismic(MS)events occurred in each of the parallel tunnels during excavation.Rockbursts occurred most frequently in certain local sections of the two tunnels.Significant differences are found in the excavation-induced microseismicity(spatial distribution and number of MS events,distribution of MS energy,and pattern of microseismicity variation)and rockbursts characteristics(the number and the spatial distribution)between the parallel tunnels.Attempting to predict the microseismicity and rockburst intensities likely to be encountered in subsequent tunnel based on the activity encountered when the parallel tunnel was previously excavated will not be an easy or accurate procedure in deep tunnel projects involving complex lithological conditions.展开更多
In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video...In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video-monitoring system (RVMS) are analyzed. Then a RVMS framework model based on softswitch is given. Furthermore, designation and realization of the system based on T 6000 Softswitch Platform is provided. The innovation is considering the RVMS as a part of softswitch system. It is a feasible scheme for implementing next generation video-monitoring system based on broadband IP technique.展开更多
文摘An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were empty and a total of 628 looks plump. Soft X ray radiographs showed that, still and all, a majority of the “plump" seeds were embryoless (597, 95.6%) whereas some were partially developed (17,2.7%) and only a few were really full (14, 2.2%). 2. Germination test showed that all of the radiographed hybrid seeds with fully developed embryos were germinable whereas those with partially developed embryos were ungerminable. 3. Physiologically, the growth rate of hypocotyl, the date for shedding of seed coat and spreading of cotyledons, the elongation of epicotyl, and the branching of shoot of the 11 month old seedlings showed a tendency to fall behind those of the female parent; morphologically, the 11 month old hybrid seedlings with linear leaves appeared rather short, slender and weak, whereas the seedlings of the female parents with linear_lanceolate leaves appeared rather tall, stout and strong. 4. It is considered that the hybrid may be true and the crossability reveals a close phylogenetic affinity of Cunninghamia with Cryptomeria.
文摘The low altitude airspace will be open in China, general aviation flights are tremendously increased. Whether aircrafts can fly safely and how to determine the requirements of safety flight are the problems needed to be confirmed. Under this circumstances, based on the international Civil Aviation Organization（ICAO） criteria and the standards made by CAAC, this paper adopts the ＂See and Avoid＂ principle. Under the binding conditions of flight rules, visibility requirements, responding time, the aircraft speed, circle banking angle or the climbing angle, based on its study on aircraft dynamics principles, this paper establishes a mathematical collision avoidance model for head-to-head traffic and crossing converging traffic at the same level. And the safety separation requirements of the aircrafts in low altitude flight are equantitatively analyzed. Finally, the Matlab software is used to analyze the above method. The result shows that the safe traffic avoidance of the converging traffic at the same level meets certain flight conditions, while intersecting the traffic at the same level can safely avoid the collision.
文摘In the study and implementation of a programmable RS codec module in satellite communication modem, FPGA is used as the kernel in the implementation, while some ASICs are used as necessary assistant measures. The module includes the RS codec unit, the interleaver and deinterleaver unit, the scrambler and descrambler unit and the frame synchronization unit. The module is realized successfully and it can be programmed on-line to meet the requirements of IESS 308/309/310 including many specifications about different service types and data rates. With the implementation combining FPGA with ASICs, size of the circuit is much reduced, its flexibility dramatically increased, and its stability further strengthened. Furthermore, the module is based on the software radio concept and can be easily integrated into the whole satellite communication modem.
基金The National Natural Science Foundation of China (No.51178348)
文摘The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array design（OAD） is used and factors such as SBS modifier content,storage time,storage temperature and container size are chosen in a mixed-level OAD with an OA16（31×44） matrix.Parameters like the separation softening point difference（the separation difference of the ring and ball softening point of the top and bottom samples） and the average softening point（the arithmetic mean of the softening points of the top and bottom samples） are proposed to evaluate the separation and the ageing of modified bitumen during storage in this experiment,respectively.The results reveal that the separation and the ageing during storage exhibit a complicated variation for storage temperature and time.The separation softening point difference decreases with the storage temperature rising from 20 to 120 ℃ and increases with the temperature exceeding 120 ℃,and the average softening point drops with the storage time being prolonged.Different storage conditions have various effects on the storage stability of SBS modified bitumen.
基金Projects(41972295,U1965205)supported by the National Natural Science Foundation of ChinaProject(2019ZDK034)supported by the Guangxi Key Laboratory of Disaster Prevention and Engineering Safety,China。
文摘Excavation-induced microseismicity and rockburst occurrence in deep underground projects provide invaluable information that can be used to warn rockburst occurrence,facilitate rockburst mitigation procedures,and analyze the mechanisms responsible for their occurrence.Based on the deep parallel tunnels with the maximum depth of 1890 m created as part of the Neelum–Jhelum hydropower project in Pakistan,similarities and differences on excavation-induced microseismicity and rockburst occurrence between parallel tunnels with soft and hard alternant strata are studied.Results show that a large number of microseismic(MS)events occurred in each of the parallel tunnels during excavation.Rockbursts occurred most frequently in certain local sections of the two tunnels.Significant differences are found in the excavation-induced microseismicity(spatial distribution and number of MS events,distribution of MS energy,and pattern of microseismicity variation)and rockbursts characteristics(the number and the spatial distribution)between the parallel tunnels.Attempting to predict the microseismicity and rockburst intensities likely to be encountered in subsequent tunnel based on the activity encountered when the parallel tunnel was previously excavated will not be an easy or accurate procedure in deep tunnel projects involving complex lithological conditions.
文摘In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video-monitoring system (RVMS) are analyzed. Then a RVMS framework model based on softswitch is given. Furthermore, designation and realization of the system based on T 6000 Softswitch Platform is provided. The innovation is considering the RVMS as a part of softswitch system. It is a feasible scheme for implementing next generation video-monitoring system based on broadband IP technique.
