The physical characteristics of phase quantum are further revealed,based on the proposition of concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution and equ...The physical characteristics of phase quantum are further revealed,based on the proposition of concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution and equivalent phase comparison frequency.Then the problem of phase comparison between different frequency signals is certified in detail.Using the basic principle of phase comparison between different frequencies and the variation law of group phase difference,a point of view on group phase quantization is presented.Group phase quantum is not only an indivisible individual of group phase,but also a basic unit composing group phase difference.It is equal to the equivalent phase comparison period of phase comparison between different frequencies in size.Experimental results show not only a high measurement resolution of 10^(-12)/s in frequency measurement based on group phase quantum,but also a super-high locked phase precision of 10^(-13)/s in active H atomic clock.展开更多
This paper conducts research on the algorithm to improve the location of Wireless Sensor Network (WSN) in Intelligent Transportation System (ITS). The localization algorithm introduced an improved RSSI vehicle loc...This paper conducts research on the algorithm to improve the location of Wireless Sensor Network (WSN) in Intelligent Transportation System (ITS). The localization algorithm introduced an improved RSSI vehicle localization algorithm based on multi-path effect and Gaussian white noise. The localization results under different values of Gaussian white noise and different density of beacon nodes are analyzes, and Kalman filtering algorithm is introduced to reduce the influence of signal noise. Finally, a simulation model of ITS is developed to test the algorithm based on mixed noise and Kalman filtering algorithm, which is used to simulate the localization of real vehicles. The simulation shows the algorithm has effect to improve location accuracy and to application展开更多
Based on the principle of equivalent phase comparison frequency, we propose a group-period phase comparison method. This method can be used to reveal the inherent relations between periodic signals and the change laws...Based on the principle of equivalent phase comparison frequency, we propose a group-period phase comparison method. This method can be used to reveal the inherent relations between periodic signals and the change laws of the phase difference. If these laws are applied in the processing of the mutual relations between frequency signals, phase comparison can be accomplished without frequency normalization. Experimental results show that the method can enhance the measurement resolution to 10-13/s in the time domain.展开更多
Based on the principle of quantized delay-time, a super-high resolution time interval measurement method is proposed based on time-space relationships. Using the delay-time stability that time and frequency signal tra...Based on the principle of quantized delay-time, a super-high resolution time interval measurement method is proposed based on time-space relationships. Using the delay-time stability that time and frequency signal travel in a specific medium, the measured time interval can be quantized. Combined with the phase coincidence detection technique, the measurement of time can be changed into the measurement of space length. The resolution and the stability of the measurement system are easily improved. Experimental results show that the measurement resolution of the measured time interval depends on the length difference of the double delay-time unit. When the length difference is set up on millimeter level or sub-millimeter level, super-high measurement resolution from hundreds of picosecond to tens of picosecond can be obtained.展开更多
Soil quality is a comprehensive reflection of soil properties.Since the soil quality concept was put forward in the 1970s,the quality of different type soils in different regions have been evaluated through a variety ...Soil quality is a comprehensive reflection of soil properties.Since the soil quality concept was put forward in the 1970s,the quality of different type soils in different regions have been evaluated through a variety of evaluation methods,but it still lacks universal soil quantity evaluation models and methods.In this paper,the applications and prospects of grey relevancy comprehensive evaluation model,attribute hierarchical model,fuzzy comprehensive evaluation model,matter-element model,RAGA-based PPC /PPE model and GIS model in soil quality evaluation are reviewed.展开更多
The bipolar compressible Euler-Maxwell equations as a fluid dynamic model arising from plasma physics to describe the dynamics of the compressible electrons and ions is investigated. This work is concerned with three-...The bipolar compressible Euler-Maxwell equations as a fluid dynamic model arising from plasma physics to describe the dynamics of the compressible electrons and ions is investigated. This work is concerned with three-dimensional Euler-Maxwell equations with smooth periodic solutions. With the help of the symmetry operator techniques and energy method, the global smooth solution with small amplitude is constructed around a constant equilibrium solution with asymptotic stability property.展开更多
Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research a...Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research at home and abroad regardless of the mention of its development of a national strategic level, it is called the third wave of the world information industry following the computer, and internet.展开更多
With the rapid development of China' s economy and the accelerating pace of economic globalization, the rapid expansion of trade appears in goods, materials; space to move also will expand in breadth and depth, and t...With the rapid development of China' s economy and the accelerating pace of economic globalization, the rapid expansion of trade appears in goods, materials; space to move also will expand in breadth and depth, and thus the efficiency of the logistics activities, rapid response capabilities and the level of information logistics put forward higher requirements. Meanwhile, the logistics needs of personalization, diversification and sophistication, require that logistics service companies must constantly improve and optimize enterprise business model, and target to develop new logistics services to adapt to changes in the logistics market, and improve the competitiveness of enterprises.Modem logistics enterprises refer to the concept of modem logistics as a guide, and the use of modem logistics and organization of modem logistics technology, it is to provide customers help and reduce logistics costs and improve the level of integrated logistics services to rationalize logistics enterprises. Modem logistics enterprises are in terms of philosophy, mode of operation, services, information technology degree, logistics technology, enterprise systems and others have higher requirements to react quickly, service serialization, standardization of operations, the target of systematic, modem means are the features of the organization which are different from the traditional network of logistics enterprises.展开更多
The paper discusses the "Writing Test" in College English Test - Band Four in two aspects. One is the design of the "Writing" form; the other is the scoring process. From the discussion the paper comes to a conclu...The paper discusses the "Writing Test" in College English Test - Band Four in two aspects. One is the design of the "Writing" form; the other is the scoring process. From the discussion the paper comes to a conclusion that the "Writing Test" in CET-4 should be reformed in two ways: the single style of the "Writing" structure should be changed to various styles in design, and the "global scoring" principle used in marking the writing should be changed to "local scoring". At last, the author suggests some ways of how to put the reforming into reality,展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60772135 and 10978017the CAST Innovation Foundation of China under Grant No 20080403 and the Open Fund of Key Laboratory of Time and Frequency Primary Standards(CAS).
文摘The physical characteristics of phase quantum are further revealed,based on the proposition of concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution and equivalent phase comparison frequency.Then the problem of phase comparison between different frequency signals is certified in detail.Using the basic principle of phase comparison between different frequencies and the variation law of group phase difference,a point of view on group phase quantization is presented.Group phase quantum is not only an indivisible individual of group phase,but also a basic unit composing group phase difference.It is equal to the equivalent phase comparison period of phase comparison between different frequencies in size.Experimental results show not only a high measurement resolution of 10^(-12)/s in frequency measurement based on group phase quantum,but also a super-high locked phase precision of 10^(-13)/s in active H atomic clock.
文摘This paper conducts research on the algorithm to improve the location of Wireless Sensor Network (WSN) in Intelligent Transportation System (ITS). The localization algorithm introduced an improved RSSI vehicle localization algorithm based on multi-path effect and Gaussian white noise. The localization results under different values of Gaussian white noise and different density of beacon nodes are analyzes, and Kalman filtering algorithm is introduced to reduce the influence of signal noise. Finally, a simulation model of ITS is developed to test the algorithm based on mixed noise and Kalman filtering algorithm, which is used to simulate the localization of real vehicles. The simulation shows the algorithm has effect to improve location accuracy and to application
基金Supported by the National Natural Science Foundation of China under Grant Nos 60772135 and 10703004, and the CAST Innovation Foundation of China under Grant No 20080403.
文摘Based on the principle of equivalent phase comparison frequency, we propose a group-period phase comparison method. This method can be used to reveal the inherent relations between periodic signals and the change laws of the phase difference. If these laws are applied in the processing of the mutual relations between frequency signals, phase comparison can be accomplished without frequency normalization. Experimental results show that the method can enhance the measurement resolution to 10-13/s in the time domain.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60772135 and 10703004, and the CAST Innovation Foundation of China under Grant No 20080403.
文摘Based on the principle of quantized delay-time, a super-high resolution time interval measurement method is proposed based on time-space relationships. Using the delay-time stability that time and frequency signal travel in a specific medium, the measured time interval can be quantized. Combined with the phase coincidence detection technique, the measurement of time can be changed into the measurement of space length. The resolution and the stability of the measurement system are easily improved. Experimental results show that the measurement resolution of the measured time interval depends on the length difference of the double delay-time unit. When the length difference is set up on millimeter level or sub-millimeter level, super-high measurement resolution from hundreds of picosecond to tens of picosecond can be obtained.
基金Supported by the Chinese National Public Benefit Program for Forestry(No. 200804040)the National Natural Science Foundation of China(31270664)+2 种基金the Foundation of State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciencesthe Program Sponsored for Scientific Innovation Research of College Graduate in Jiangsu Province (CX10B_248Z)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Soil quality is a comprehensive reflection of soil properties.Since the soil quality concept was put forward in the 1970s,the quality of different type soils in different regions have been evaluated through a variety of evaluation methods,but it still lacks universal soil quantity evaluation models and methods.In this paper,the applications and prospects of grey relevancy comprehensive evaluation model,attribute hierarchical model,fuzzy comprehensive evaluation model,matter-element model,RAGA-based PPC /PPE model and GIS model in soil quality evaluation are reviewed.
基金Supported by the Foundation Project of Doctor Graduate Student Innovation of Beijing University of Technology(ykj-2012-6724)Supported by the NSFC(10771009)Supported by the BSF(1082001)
文摘The bipolar compressible Euler-Maxwell equations as a fluid dynamic model arising from plasma physics to describe the dynamics of the compressible electrons and ions is investigated. This work is concerned with three-dimensional Euler-Maxwell equations with smooth periodic solutions. With the help of the symmetry operator techniques and energy method, the global smooth solution with small amplitude is constructed around a constant equilibrium solution with asymptotic stability property.
文摘Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research at home and abroad regardless of the mention of its development of a national strategic level, it is called the third wave of the world information industry following the computer, and internet.
文摘With the rapid development of China' s economy and the accelerating pace of economic globalization, the rapid expansion of trade appears in goods, materials; space to move also will expand in breadth and depth, and thus the efficiency of the logistics activities, rapid response capabilities and the level of information logistics put forward higher requirements. Meanwhile, the logistics needs of personalization, diversification and sophistication, require that logistics service companies must constantly improve and optimize enterprise business model, and target to develop new logistics services to adapt to changes in the logistics market, and improve the competitiveness of enterprises.Modem logistics enterprises refer to the concept of modem logistics as a guide, and the use of modem logistics and organization of modem logistics technology, it is to provide customers help and reduce logistics costs and improve the level of integrated logistics services to rationalize logistics enterprises. Modem logistics enterprises are in terms of philosophy, mode of operation, services, information technology degree, logistics technology, enterprise systems and others have higher requirements to react quickly, service serialization, standardization of operations, the target of systematic, modem means are the features of the organization which are different from the traditional network of logistics enterprises.
文摘The paper discusses the "Writing Test" in College English Test - Band Four in two aspects. One is the design of the "Writing" form; the other is the scoring process. From the discussion the paper comes to a conclusion that the "Writing Test" in CET-4 should be reformed in two ways: the single style of the "Writing" structure should be changed to various styles in design, and the "global scoring" principle used in marking the writing should be changed to "local scoring". At last, the author suggests some ways of how to put the reforming into reality,