Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transforma...Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.展开更多
The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resol...The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.展开更多
文摘Two-dimensional physical models of low crested breakwaters were tested to establish the effect of water depth, crest width, slope, stone size, core permeability and incident wave characteristics on the wave transformation processes. The structure of the breakwaters can be used as coastal protection system by reducing the amount of incoming wave energy. Effect of slope, core permeability, water depth and incident wave characteristics on the stability was also studied. The breakwater model consisted of a core and two armour layers attacked by irregular waves. This paper discusses and compares the test results with the existing design equations. In general, the existing design equations do not seem to predict the wave transmission and reflection accurately for the range of test data. In the range of variable tested, it was observed that the water depth, crest width and wave period have a significant influence on wave transmission process. Further, results show strong influence of the water depth and wave period on the wave reflection process. The structural stability of low crested breakwaters is very much affected by the water depth and wave period.
基金supported by the Joint Fund for Fostering Talents of National Natural Science Foundation of China and Henan Province(Grant No.U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No.2012PNTT01)+4 种基金the Postdoctoral Grant of China(Grant Nos.2011M501446,2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province(Grant No.122300410169)The Key Science and Technology Foundation of Zhengzhou City(Grant Nos.131PPTGG411-6,131PCXTD594)the Doctor Fund of Zhengzhou University of Light Industry(Grant No.2011BSJJ031)the Fundamental Research Funds for the Central Universities(Grant No.K5051204003)
文摘The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.
