[Objective] The aim was to research the relationships among different e- valuation farmland units and conduct division-of farmland use in order to provide scientific references for protection and rational use of farml...[Objective] The aim was to research the relationships among different e- valuation farmland units and conduct division-of farmland use in order to provide scientific references for protection and rational use of farmland at county level. [Method] Using Pingdu City as a case, the research selected land use indices such as farmland use structure, output, geographical location, eta/., and then performed a cluster analysis for farmland use division. [Result] Farmlands in Pingdu can be classified into 4 groups. In groups 1 and 2, it is necessary to strengthen farmland protection, especially for highly-quality farmlands, to guarantee the quantity and quality of local crops. In groups 1 and 3, it is necessary to improve concentration degree and use rate of construction lands and control farmland pollution possibly caused by constructions. In group 4, priority should be given to maintaining diversity of land use patterns, and avoiding aimless farming expansion. [Conclusion] During urbanization process in eastern coastal agricultural regions, it is of importance to prevent fertile farmlands being occupied by construction lands to enhance use rate of construction lands. Furthermore, agricultural non-point pollution should be detected constantly in intensively used farmlands, especially in vegetable fields. Additionally, land use diversity should be well protected by avoiding farmland expansion and im- proving farmland environment.展开更多
This paper attempts to analyze geothermy revealed by the sounding data at 8 h and 20 h every day from China Meteorological Administration and the data counted per minute such as the wellhead temperature,the electromag...This paper attempts to analyze geothermy revealed by the sounding data at 8 h and 20 h every day from China Meteorological Administration and the data counted per minute such as the wellhead temperature,the electromagnetic disturbance,the ground tilt and so of water level instrument in Sanxing of Chengdu with the method of information digitization.The result shows the recognizable differentiation of the change process before and after the earthquake,provides an analytic method for the improvement of earthquake prediction or prevention,and shows the feasible further research and the wide application prospect.展开更多
Gap statistic is a well-known index of clustering validity, but its realization is difficult to be comprehended and accurately determined. A direct method is presented to improve the performance of the Gap statistic, ...Gap statistic is a well-known index of clustering validity, but its realization is difficult to be comprehended and accurately determined. A direct method is presented to improve the performance of the Gap statistic, which applies the two-order difference of within-cluster dispersion to replace the constructed null reference distribution in the Gap statistic. Hence, the realization of the Gap statistic becomes easy and is reformulated, and its uncertainty in applications is reduced. Also, the limitation of the Gap statistic is analyzed by two typical examples, that is, the Gap statistic is difficult to be applied to the dataset that contains strong-overlap or uneven-density clusters. Experiments verify the usefulness of the proposed method.展开更多
This paper reports on an evaluation of airborne sound insulation in a wider frequency range then is used in classical measurements. For analyzing sound insulation was used frequency range from 50 Hz to 10 kHz via stan...This paper reports on an evaluation of airborne sound insulation in a wider frequency range then is used in classical measurements. For analyzing sound insulation was used frequency range from 50 Hz to 10 kHz via standard range I00 Hz to 3,15 kHz. For four constructions with different structure was measured sound reduction index depend on frequency and calculated Weighted sound reduction index according to EN ISO 717-1. Then the results were compared. The measurements were made for samples of construction with different sizes. The results of measurements show how the size of sample influence on measured sound insulation. This article could be useful for specialist of architect acoustic and all who interest in sound insulation.展开更多
Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan ...Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan Desert area, we use the multi-channel analysis of surface wave （MASW） method to process multi-channel shallow surface wave records to determine the near surface velocity structure in the desert area. We also process, analyze, and compare the surface waves in many-trace records extracted from the oil exploration shot gathers in the area. We show that the MASW method can determine detailed shallow velocity structure in desert areas and the many-trace records can be used to get detailed deep geological structure. The combination of the two different datasets can obtain the exact velocity structure upper 60 m depth in the survey area.展开更多
Concrete dam construction, reservoir impoundment and operation are a complicated and long-term process. During the course of this process dam suffers lots of factors including changing temperature, humidity, deformati...Concrete dam construction, reservoir impoundment and operation are a complicated and long-term process. During the course of this process dam suffers lots of factors including changing temperature, humidity, deformation, loads and restraints around dam. With time going by, damage to darn concrete happens. As a result, the strength, stiffness and resistance of concrete will decrease accompanying with damage accumulation and dam structure performance behavior and lifetime will be shorten or even destructed. At present, most of researches focus on concrete material itself and seldom consider effects of water content for concrete structures. That is apparently inconsistent with the actual situation. In engineering practice, it is urgently needed to assess existing dam structure damage state considering dry zoning in concrete. Through taking C30 dam concrete as standard specimen, alternate freezing and thawing tests are undertaken and changing law of time-dependent concrete damage state resulting in alternate wetting and drying has been studied in this paper. And then calculation formulas of time-dependent concrete damage evolution process considering alternate wetting and drying under condition of freeze-thaw cycle tests are established. Combining with four parameters Hsieh-Ting-Chen （ H -T-C ） model, some relevant factors or parameters are obtained through indoor testing and life prediction model of concrete dam based on dry zoning and damage theory is put forward which provides technical supports for dam safety evaluation and management of sustainable development.展开更多
Urban integrated activity zone （UIAZ） refers to multi-functional area that can provide various services. Integrated activity zone （IAZ）, which is based on the existing financial district and Central Business Distr...Urban integrated activity zone （UIAZ） refers to multi-functional area that can provide various services. Integrated activity zone （IAZ）, which is based on the existing financial district and Central Business District （CBD）, often weakens administrative boundaries and changes the original single functional partition. It emphasizes the mixture of different functions and the vitality of the central area. The construction of IAZ is different from the simple space construction of economy and material production. IAZ emphasizes the participation of city dwellers in urban renewal process. Shanghai IAZs are those vigorous public activity centers in Shanghai. ]ust like those active cells, IAZs in Shanghai are to inspire and improve the comprehensive competitiveness and vitality of the city at macro, intermediate, and micro level, they are the public places in which urban cultural life takes place, develops, and precipitates. This paper provides broad and profound presentation on IAZ structure planning in Shanghai： mix-used function, multi-dimensions scale, people oriented development （POD） transportation, commercial development, and city form vitality. This paper provides not only qualitative analysis, but also makes a serious attempt to quantify the result and statement.展开更多
This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic...This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic density function approach,we employ the nonparametric analysis to characterize the spatial pattern of population densities in the Beijing metropolitan area and identify the suburban subcenters.Our findings suggest that the population has spread with rapid urban growth in the Beijing metropolitan area,and the compact urban form has been replaced by a more dispersed polycentric spatial distribution.However,compared with the decentralization of western cities,the spatial extent of the decentralization of population in the Beijing metropolitan area is quite limited.The rapid growth of population in the near suburbs has expedited the sprawl of the central city,with a larger central agglomeration of population dominating the metropolitan area.In this sense,the spatial pattern of the Beijing metropolitan area is still characterized by the continuous compactness.However,our findings do provide the evidence that the city has been turning to a polycentric structure.We find significant population subcenters have emerged in the suburbs of Beijing since the 1980s.But the polycentricity emerged in the Beijing metropolitan area is very different by nature from that observed in Western cities.The subcenters emerged are adherent to the development scheme planned for the city,so it can be referred to as the so called 'planned polycentricity'.展开更多
基金Supported by National Natural Science Foundation of China[41371531(2014-2017)]~~
文摘[Objective] The aim was to research the relationships among different e- valuation farmland units and conduct division-of farmland use in order to provide scientific references for protection and rational use of farmland at county level. [Method] Using Pingdu City as a case, the research selected land use indices such as farmland use structure, output, geographical location, eta/., and then performed a cluster analysis for farmland use division. [Result] Farmlands in Pingdu can be classified into 4 groups. In groups 1 and 2, it is necessary to strengthen farmland protection, especially for highly-quality farmlands, to guarantee the quantity and quality of local crops. In groups 1 and 3, it is necessary to improve concentration degree and use rate of construction lands and control farmland pollution possibly caused by constructions. In group 4, priority should be given to maintaining diversity of land use patterns, and avoiding aimless farming expansion. [Conclusion] During urbanization process in eastern coastal agricultural regions, it is of importance to prevent fertile farmlands being occupied by construction lands to enhance use rate of construction lands. Furthermore, agricultural non-point pollution should be detected constantly in intensively used farmlands, especially in vegetable fields. Additionally, land use diversity should be well protected by avoiding farmland expansion and im- proving farmland environment.
文摘This paper attempts to analyze geothermy revealed by the sounding data at 8 h and 20 h every day from China Meteorological Administration and the data counted per minute such as the wellhead temperature,the electromagnetic disturbance,the ground tilt and so of water level instrument in Sanxing of Chengdu with the method of information digitization.The result shows the recognizable differentiation of the change process before and after the earthquake,provides an analytic method for the improvement of earthquake prediction or prevention,and shows the feasible further research and the wide application prospect.
基金National Natural Science Foundation of China(No.60572065, 60772080, 60532020)
文摘Gap statistic is a well-known index of clustering validity, but its realization is difficult to be comprehended and accurately determined. A direct method is presented to improve the performance of the Gap statistic, which applies the two-order difference of within-cluster dispersion to replace the constructed null reference distribution in the Gap statistic. Hence, the realization of the Gap statistic becomes easy and is reformulated, and its uncertainty in applications is reduced. Also, the limitation of the Gap statistic is analyzed by two typical examples, that is, the Gap statistic is difficult to be applied to the dataset that contains strong-overlap or uneven-density clusters. Experiments verify the usefulness of the proposed method.
文摘This paper reports on an evaluation of airborne sound insulation in a wider frequency range then is used in classical measurements. For analyzing sound insulation was used frequency range from 50 Hz to 10 kHz via standard range I00 Hz to 3,15 kHz. For four constructions with different structure was measured sound reduction index depend on frequency and calculated Weighted sound reduction index according to EN ISO 717-1. Then the results were compared. The measurements were made for samples of construction with different sizes. The results of measurements show how the size of sample influence on measured sound insulation. This article could be useful for specialist of architect acoustic and all who interest in sound insulation.
文摘Shallow surface wave methods are mostly used for investigation of the surface velocity structure in environmental and engineering geophysics in non-desert areas. For the special geological features of the Takelamagan Desert area, we use the multi-channel analysis of surface wave （MASW） method to process multi-channel shallow surface wave records to determine the near surface velocity structure in the desert area. We also process, analyze, and compare the surface waves in many-trace records extracted from the oil exploration shot gathers in the area. We show that the MASW method can determine detailed shallow velocity structure in desert areas and the many-trace records can be used to get detailed deep geological structure. The combination of the two different datasets can obtain the exact velocity structure upper 60 m depth in the survey area.
基金This research was supported by NSFC （National Natural Science Foundation of China） （Granted No.： 50909054, 50925933）.
文摘Concrete dam construction, reservoir impoundment and operation are a complicated and long-term process. During the course of this process dam suffers lots of factors including changing temperature, humidity, deformation, loads and restraints around dam. With time going by, damage to darn concrete happens. As a result, the strength, stiffness and resistance of concrete will decrease accompanying with damage accumulation and dam structure performance behavior and lifetime will be shorten or even destructed. At present, most of researches focus on concrete material itself and seldom consider effects of water content for concrete structures. That is apparently inconsistent with the actual situation. In engineering practice, it is urgently needed to assess existing dam structure damage state considering dry zoning in concrete. Through taking C30 dam concrete as standard specimen, alternate freezing and thawing tests are undertaken and changing law of time-dependent concrete damage state resulting in alternate wetting and drying has been studied in this paper. And then calculation formulas of time-dependent concrete damage evolution process considering alternate wetting and drying under condition of freeze-thaw cycle tests are established. Combining with four parameters Hsieh-Ting-Chen （ H -T-C ） model, some relevant factors or parameters are obtained through indoor testing and life prediction model of concrete dam based on dry zoning and damage theory is put forward which provides technical supports for dam safety evaluation and management of sustainable development.
文摘Urban integrated activity zone （UIAZ） refers to multi-functional area that can provide various services. Integrated activity zone （IAZ）, which is based on the existing financial district and Central Business District （CBD）, often weakens administrative boundaries and changes the original single functional partition. It emphasizes the mixture of different functions and the vitality of the central area. The construction of IAZ is different from the simple space construction of economy and material production. IAZ emphasizes the participation of city dwellers in urban renewal process. Shanghai IAZs are those vigorous public activity centers in Shanghai. ]ust like those active cells, IAZs in Shanghai are to inspire and improve the comprehensive competitiveness and vitality of the city at macro, intermediate, and micro level, they are the public places in which urban cultural life takes place, develops, and precipitates. This paper provides broad and profound presentation on IAZ structure planning in Shanghai： mix-used function, multi-dimensions scale, people oriented development （POD） transportation, commercial development, and city form vitality. This paper provides not only qualitative analysis, but also makes a serious attempt to quantify the result and statement.
基金Under the auspices of National Key Basic Research Program of China (No. 2012CB955802)National Natural Science Foundation of China (No. 41001069)Grant Program of National Social Science Foundation of China (No.10zd&022)
文摘This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic density function approach,we employ the nonparametric analysis to characterize the spatial pattern of population densities in the Beijing metropolitan area and identify the suburban subcenters.Our findings suggest that the population has spread with rapid urban growth in the Beijing metropolitan area,and the compact urban form has been replaced by a more dispersed polycentric spatial distribution.However,compared with the decentralization of western cities,the spatial extent of the decentralization of population in the Beijing metropolitan area is quite limited.The rapid growth of population in the near suburbs has expedited the sprawl of the central city,with a larger central agglomeration of population dominating the metropolitan area.In this sense,the spatial pattern of the Beijing metropolitan area is still characterized by the continuous compactness.However,our findings do provide the evidence that the city has been turning to a polycentric structure.We find significant population subcenters have emerged in the suburbs of Beijing since the 1980s.But the polycentricity emerged in the Beijing metropolitan area is very different by nature from that observed in Western cities.The subcenters emerged are adherent to the development scheme planned for the city,so it can be referred to as the so called 'planned polycentricity'.
