[Objective] This study aimed to investigate the immunological adjuvant function of aluminium phosphate and chicken IL-18 in NDV F gene vaccine. [Method] The vaccine (0.2 ml) containing aluminum phosphate adjuvant (...[Objective] This study aimed to investigate the immunological adjuvant function of aluminium phosphate and chicken IL-18 in NDV F gene vaccine. [Method] The vaccine (0.2 ml) containing aluminum phosphate adjuvant (90 μg), pcDNA/F (200μg), and pcDNA/chlL-18 (200 μg) was prepared. The 7 d old chick- ens to be tested were randomly divided into six groups (12 chickens in each group) and immunized through intramuscular injection with inactivated Newcastle disease vaccines, pcDNA/F+pcDNA/chlL-18+phosphate aluminum, pcDNA/F, pcDNA/F.+pcDNA/ chlL-18, pcDNA/F+aluminum phosphate, and physiological saline respectively; the secondary immunization was conducted with the same dose when the chickens were 21 d old. Their blood was sampled 0, 7, 14, 21, 28 d after first immunization. Anti- body titer was detected with ELISA and T cell transformation rate was measured with MIT. Experimental chicken will be challenged with 30 LD50 NDV virulence 28 d after first immunization. [Result] The survival rate of the chickens immunized with pcDNA/F+aluminium phosphate+pcDNA/chlL-18 achieved 8/12, higher than that of those immunized with pcDNA/F 4/12 and pcDNA/F+pcDNA/chlL-18 (6/12). The NDV antibody titer of the chickens immunized with pcDNA/F+ aluminum phosphate, pcD- NA/F+pcDNA/chlL-18 and pcDNA/F+pcDNA/chlL-18+aluminum phosphate is not differ- ent (P〉0.05), but significantly lower than that of the chickens immunized with tradi- tional vaccine (P〈0.05). The T cell transformation rate of the chickens immunized with pcDNA/F+pcDNA/chlL-18+aluminium phosphate was obviously higher than that of the chickens immunized with pcDNA/F (P〈0.05). The T cell transformation rates of chickens immunized with pcDNA/F and the traditional vaccine showed no signifi- cant difference (P〉0.05). [Conclusion] Combination of aluminium phosphate and pcD- NA/chlL-18 can significantly enhance the immune effect of NDV F gene vaccine.展开更多
The macroscopic fundamental diagram( MFD) is studied to obtain the aggregate behavior of traffic in cities. This paper investigates the existence and the characteristics of different types of daily MFD for the Shang...The macroscopic fundamental diagram( MFD) is studied to obtain the aggregate behavior of traffic in cities. This paper investigates the existence and the characteristics of different types of daily MFD for the Shanghai urban expressway network. The existence of MFD in the Shanghai urban expressway network is proved based on two weeks' data.Moreover, the hysteresis phenomena is present in most days and the network exhibits different hysteresis loops under different traffic situations. The relationship between the hysteresis phenomena and the inhomogeneity of traffic distribution is verified. The MFDs in the years of 2009 and 2012 are compared. The hysteresis loop still exists in 2012, which further verifies the existence of the hysteresis phenomenon. The direct relationship between the length of the hysteresis loop( ΔO) and the congestion is proved based on sufficient data. The width of the hysteresis loop, i. e., the drop in network flow( ΔQ) has no relationship with the congestion, and it varies from day to day under different traffic situations.展开更多
Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double ended, shear...Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double ended, shear combined and valve typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 kN while the maximum power required is less than 50 W, which predicts that the MR damper will be a powerful measurement for semi active vibration control of civil infrastructures.展开更多
A balance of urban datum land prices is achieved to harmonize regional land prices and make the prices truly reflect different economic development levels and land prices among cities. The current piecewise linear int...A balance of urban datum land prices is achieved to harmonize regional land prices and make the prices truly reflect different economic development levels and land prices among cities. The current piecewise linear interpolation balance method widely used has two drawbacks that always lead to an unsatisfactory balance among some cities. When the excess of land price in the central city to the surrounding zone reaches a certain degree, land price in the circumjacent city is not only consistent with the local land grade and land use level, but also influenced by the diffusion of land price in the central city. Thus, a new balanced scheme of datum land prices based on the city gravitation model and stochastic diffusion equation is brought forward. Finally, the new method is examined in the practice of datum land price balance in Hubei Province, China.展开更多
Like the hard surfaces of streets and sidewalks in an urban environment, the vertical and horizontal surface area on the outside of urban buildings contributes to the constant heating of large cities around the world....Like the hard surfaces of streets and sidewalks in an urban environment, the vertical and horizontal surface area on the outside of urban buildings contributes to the constant heating of large cities around the world. However, little is done to design this surface to benefit the public sphere. Instead, the facade of a building performs either as a component that focuses only on the quality of comfort for interior occupants, while ignoring effects on the exterior of the building, or as an identifiable aesthetic for the building's owners, This essay proposes the rethinking of the building facade as a steward of outdoor pedestrian welfare, and the conception of public health as an added function of the building envelope- a concept that may fall into the jurisdiction of public works. If the huge total surface area of a city's buildings is thought of as part of the city's infrastructure, then its public contribution may not only make outdoor areas comfortable, clean, and enjoyable, but also help to alleviate the bigger problem of rising temperatures in cities.展开更多
In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is p...In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is proposed by considering the first verticalvibration mode. Taking a light railproject in Tianjin as an example, this study uses the proposed discrete modelto analyze the displacements of tunneland soilunder verticalearthquake excitations. The soildisplacement responses at different tunnellocations are analyzed with linear random vibration theory.The computationalcost is greatly reduced using the proposed model. It can be seen that different from the case of horizontalearthquakes, the displacement responses under verticalearthquake excitations keep growing after seismic acceleration reaches its peak for a short duration, and then,they begin to decay. The soils at different positions around the tunnels have large relative displacement under verticalearthquake excitations. Moreover, a finite-element modelis also established for displacement responses using ABAQUS.The comparison with the results of the finite-element modelshows that the results of the proposed discrete modelare available.展开更多
Through a case study of Shenzhen City,China,this study focused on a quantitative method for analyzing the spatial processes involved in green infrastructure changes associated with rapid urbanization.Based on RS,GIS a...Through a case study of Shenzhen City,China,this study focused on a quantitative method for analyzing the spatial processes involved in green infrastructure changes associated with rapid urbanization.Based on RS,GIS and SPSS statistics software,the approach includes selection of the square analysis units and representative landscape metrics,quantification of the change types of landscape metrics in all analysis units through two indices and hierarchical cluster analysis of the above analysis units with different landscape metric change types(i.e.spatial attributes).The analyses verify that there is a significant sequence of continuous changes in green infrastructure in Shenzhen.They are the perforation,the segmentation,the fragmentation,the evanescence and the filling-in processes,which have a good spatio-temporal correspondence with urbanization and reflect the synthetic influence of urban planning,government policies and landforms.Compared with other studies on quantifying the spatial pattern,this study provides an alternative probe into linking the spatial pattern to spatial processes and the corresponding ecological processes in the future.These spatio-temporal processes offer many opportunities for identifying,protecting and restoring key elements in an urban green infrastructure network for areas in the early stages of urbanization or for non-urbanized areas.展开更多
The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chos...The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chosen to calculate the environmental geochemical baseline.The geoaccumulation index was calculated and mapped to indicate the environmental quality of the soil.The results show that the urban areas are barely polluted with Ni and Cr but the rural areas in the southern part of the city, and the western part of the lake,are polluted with Ni,Cr,and Cu at the second level.On the other hand,the rural areas in the southern part of the city,and the western part of the lake,are polluted with As at a moderate level.The other area is polluted at the second level.An increase in As pollution occurs in a direction from northeast to southwest.The Cd pollution follows a trend similar to As,with an additional smaller contaminated area polluted at levelⅢ.The Hg pollution typical of urban areas occurs in the main and northern parts of the city.The geochemical accumulation index decreases from the city center to the periphery.The highest pollution level reaches levelⅣ,which indicates that the soil is seriously polluted with Hg.The southern part of the city and the rural areas to the west of the lake are not contaminated with Hg.Geological factors and the disturbance from human activities are both possible major factors:further research is needed to identify them.展开更多
As a typical car-dependent city, Los Angeles (LA) is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA's geologic conditions and civil circumstance...As a typical car-dependent city, Los Angeles (LA) is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA's geologic conditions and civil circumstances, we argued that the relationship between LA's low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Off reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short constrnction-period projects enabled fast establishment of LA's highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China's motorization and urban development, we found that the trajectory of Beijing's motorization between 197g and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA's urban and transportation development should be suggestive to China's urban and transportation planning.展开更多
This paper analyses the composition, the overall importance of city infrastructure construction and promote the city in the process of meaning. Then analysis the importance of city traffic infrastructure construction,...This paper analyses the composition, the overall importance of city infrastructure construction and promote the city in the process of meaning. Then analysis the importance of city traffic infrastructure construction, the vanity of the city infrastructure and social infrastructure in the process of city, and puts forward relying on infrastructure construction to promote the urbanization development strategy.展开更多
The proper amount, the suitable structure and the tentative sources of urban infrastructure investment are the main focuses of urban policy makers. Firstly the amount of urban infrastructure investment is combinatory ...The proper amount, the suitable structure and the tentative sources of urban infrastructure investment are the main focuses of urban policy makers. Firstly the amount of urban infrastructure investment is combinatory forecasted based on historical statistic databases of China. Then the interrelationship of urban infrastructure investment with GNP and the whole society investment in fixed assets are analyzed to work out quantitative coherent relationship. Finally the paper analyses the present and the future development trends of investment structure and capital resource respectively.展开更多
According to the characteristics of the primary materials of the basic land price in the little town, the author uses the analysis function of the figures and the space to set off the rank unit,calculate the numberof ...According to the characteristics of the primary materials of the basic land price in the little town, the author uses the analysis function of the figures and the space to set off the rank unit,calculate the numberof the unit and rank the land. The method and the system of the evaluation of the basic land price in the little town (especially the little towns in the Western China) will be perfect.展开更多
Adopting the BOT (build-operate-transfer) delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT proje...Adopting the BOT (build-operate-transfer) delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT projects such as concessionaire selection criteria and risk factors. But the project execution becomes complicated such as the escalated quality supervision organization and procedure at the construction stage. This extra supervision may have constituted hidden redundancies as waste to economic sustainability. This paper investigated construction quality supervision of BOT projects to pinpoint adequate degree of supervision and detect redundant organization and procedures. The study adopted ten subway construction projects as cases in which five were from the traditional design-bid-build (DBB) and five from the BOT methods. Thirty six project participants including owners, contractors, designers, and concessionaire managers of the ten projects were interviewed to tell their views on these issues. The quality supervision measures of the DBB projects were used as the baseline and compared with those of the BOT projects. The research results show that the construction quality seems no difference for the DBB and BOT projects. Construction quality comes out of supervision but excessive supervision organization and procedures do not necessarily improve quality. This finding indicates that adequate degree of supervision is enough to achieve required quality to save immense paperwork for large construction projects.展开更多
In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localize...In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localized perspective, ‘administrative urbanization', can provide a contextual explanation for the mechanism of urbanization in the reform era. The case study of Ordos indicates that new town construction, especially in the inland area, has become the main strategy for investment attraction and economic development. The local government has played a dominant role in this construction through a series of administrative measures, including avoidance of central state regulations, land leasing, high standard infrastructure construction, relocation policies and industrial attraction. This article also explores the issue of unsustainability in the new town, and identifies that underdeveloped industrialization, slow population agglomeration and real estate bubbles are primary threats to the sustainability of administrative urbanization.展开更多
Landslides are one of the most widespread and dangerous phenomena in the urbanized territories. In Moscow they affect about 3% of the most valuable territory, including churches and historical buildings located at hig...Landslides are one of the most widespread and dangerous phenomena in the urbanized territories. In Moscow they affect about 3% of the most valuable territory, including churches and historical buildings located at high banks of the Moskva River. Recently the landslide activation occurred. Normal functioning of city infrastructure and implementation of effective slope protection measures require special landslide monitoring. Mechanical-mathematical model of high viscous fluid was applied for the landslide-prone slopes modeling. Equation of continuityand an approximatedNavier-Stockes equation f or slow motions in a thin layer were used. The results of modelling give possibility to define the landslide section with upmost velocity that should be monitored in the first place. Some important parameters used for numerical modelling can be defined from monitoring data.展开更多
To analyze China’s actual urbanization level, we iden- tified two statistical approaches: using the population living within the administrative boundaries ("administrative-based" method) and within the urba...To analyze China’s actual urbanization level, we iden- tified two statistical approaches: using the population living within the administrative boundaries ("administrative-based" method) and within the urbanized or built-up areas ("infrastructure-based" method) of cities and towns as urban population. To illustrate the two approaches and the associated problems, we used data for Tangshan City as a case study. The estimates on the "administrative-based" method were unreliable and the "infrastructurebased" method provided a 29.4% urbanization rate for Tangshan City in 2002, which is lower than the mean of 36.1% for China as a whole published after the fifth national census in 2000. Given the city’s geographic location, comprehensive urban construction and economic development indicators, its urbanization rate should be higher than the average level. Thus, our results indicate that the value of 36.1% was higher than the actual status as a result of poor statistical quality and overestimation of the floating population.展开更多
There is a high potential for small-scale and medium scale wood-fired cogeneration in Estonia. The purpose of this research is to define the eligible capacity for wood fuel based cogeneration plant operating on the ba...There is a high potential for small-scale and medium scale wood-fired cogeneration in Estonia. The purpose of this research is to define the eligible capacity for wood fuel based cogeneration plant operating on the base of district heating systems in small towns. Results were checked and approbated by economical and environmental factors. Two optimal sizing methods were used maximizing of amount of heat year-round while working at full installed capacity and maximizing of amount of heat year-round while working with partial loads. Results of defining optimal capacities for wood-fired cogeneration plants in small Estonian towns showed that method of maximizing of amount of heat year-round while working with partial loads is more adequate to real situation.展开更多
The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framewo...The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framework of information platform are presented for city infrastructure projects of our construction comprehensive control, and efficient management city infrastructure construction project, and provide collaboration platform for the party in the infrastructure construction projects.展开更多
City development is a result of many factors, of which land value is one of the major determinants. The past urban economics studies have shown that land value is largely determined by location factors such as distanc...City development is a result of many factors, of which land value is one of the major determinants. The past urban economics studies have shown that land value is largely determined by location factors such as distance from Central Business District (CBD) ignoring the non-location factors like time of purchase and neighbourhood infrastructures. Therefore, this paper attempts to establish the relative importance of location and non-location factors in the determination of residential land value by positing Onitsha, Nigeria as a case study. Eight hundred and fifty residential housing units were selected and questionnaire administered to the landlords through multi-stage sampling technique. The stepwise regression analysis results showed that non-location factors, especially, time of land purchase, contribute more to the variation in residential land values. The paper suggests the revision of the classical economic theories to represent the conditions of urban areas in developing countries .展开更多
文摘[Objective] This study aimed to investigate the immunological adjuvant function of aluminium phosphate and chicken IL-18 in NDV F gene vaccine. [Method] The vaccine (0.2 ml) containing aluminum phosphate adjuvant (90 μg), pcDNA/F (200μg), and pcDNA/chlL-18 (200 μg) was prepared. The 7 d old chick- ens to be tested were randomly divided into six groups (12 chickens in each group) and immunized through intramuscular injection with inactivated Newcastle disease vaccines, pcDNA/F+pcDNA/chlL-18+phosphate aluminum, pcDNA/F, pcDNA/F.+pcDNA/ chlL-18, pcDNA/F+aluminum phosphate, and physiological saline respectively; the secondary immunization was conducted with the same dose when the chickens were 21 d old. Their blood was sampled 0, 7, 14, 21, 28 d after first immunization. Anti- body titer was detected with ELISA and T cell transformation rate was measured with MIT. Experimental chicken will be challenged with 30 LD50 NDV virulence 28 d after first immunization. [Result] The survival rate of the chickens immunized with pcDNA/F+aluminium phosphate+pcDNA/chlL-18 achieved 8/12, higher than that of those immunized with pcDNA/F 4/12 and pcDNA/F+pcDNA/chlL-18 (6/12). The NDV antibody titer of the chickens immunized with pcDNA/F+ aluminum phosphate, pcD- NA/F+pcDNA/chlL-18 and pcDNA/F+pcDNA/chlL-18+aluminum phosphate is not differ- ent (P〉0.05), but significantly lower than that of the chickens immunized with tradi- tional vaccine (P〈0.05). The T cell transformation rate of the chickens immunized with pcDNA/F+pcDNA/chlL-18+aluminium phosphate was obviously higher than that of the chickens immunized with pcDNA/F (P〈0.05). The T cell transformation rates of chickens immunized with pcDNA/F and the traditional vaccine showed no signifi- cant difference (P〉0.05). [Conclusion] Combination of aluminium phosphate and pcD- NA/chlL-18 can significantly enhance the immune effect of NDV F gene vaccine.
基金The National Natural Science Foundation of China(No.51238008)
文摘The macroscopic fundamental diagram( MFD) is studied to obtain the aggregate behavior of traffic in cities. This paper investigates the existence and the characteristics of different types of daily MFD for the Shanghai urban expressway network. The existence of MFD in the Shanghai urban expressway network is proved based on two weeks' data.Moreover, the hysteresis phenomena is present in most days and the network exhibits different hysteresis loops under different traffic situations. The relationship between the hysteresis phenomena and the inhomogeneity of traffic distribution is verified. The MFDs in the years of 2009 and 2012 are compared. The hysteresis loop still exists in 2012, which further verifies the existence of the hysteresis phenomenon. The direct relationship between the length of the hysteresis loop( ΔO) and the congestion is proved based on sufficient data. The width of the hysteresis loop, i. e., the drop in network flow( ΔQ) has no relationship with the congestion, and it varies from day to day under different traffic situations.
文摘Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double ended, shear combined and valve typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 kN while the maximum power required is less than 50 W, which predicts that the MR damper will be a powerful measurement for semi active vibration control of civil infrastructures.
文摘A balance of urban datum land prices is achieved to harmonize regional land prices and make the prices truly reflect different economic development levels and land prices among cities. The current piecewise linear interpolation balance method widely used has two drawbacks that always lead to an unsatisfactory balance among some cities. When the excess of land price in the central city to the surrounding zone reaches a certain degree, land price in the circumjacent city is not only consistent with the local land grade and land use level, but also influenced by the diffusion of land price in the central city. Thus, a new balanced scheme of datum land prices based on the city gravitation model and stochastic diffusion equation is brought forward. Finally, the new method is examined in the practice of datum land price balance in Hubei Province, China.
文摘Like the hard surfaces of streets and sidewalks in an urban environment, the vertical and horizontal surface area on the outside of urban buildings contributes to the constant heating of large cities around the world. However, little is done to design this surface to benefit the public sphere. Instead, the facade of a building performs either as a component that focuses only on the quality of comfort for interior occupants, while ignoring effects on the exterior of the building, or as an identifiable aesthetic for the building's owners, This essay proposes the rethinking of the building facade as a steward of outdoor pedestrian welfare, and the conception of public health as an added function of the building envelope- a concept that may fall into the jurisdiction of public works. If the huge total surface area of a city's buildings is thought of as part of the city's infrastructure, then its public contribution may not only make outdoor areas comfortable, clean, and enjoyable, but also help to alleviate the bigger problem of rising temperatures in cities.
基金supported by the National Natural Science Foundation of China (No. 51478311)the Natural Science Foundation of Tianjin, China (No. 14JCQNJC07400)
文摘In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is proposed by considering the first verticalvibration mode. Taking a light railproject in Tianjin as an example, this study uses the proposed discrete modelto analyze the displacements of tunneland soilunder verticalearthquake excitations. The soildisplacement responses at different tunnellocations are analyzed with linear random vibration theory.The computationalcost is greatly reduced using the proposed model. It can be seen that different from the case of horizontalearthquakes, the displacement responses under verticalearthquake excitations keep growing after seismic acceleration reaches its peak for a short duration, and then,they begin to decay. The soils at different positions around the tunnels have large relative displacement under verticalearthquake excitations. Moreover, a finite-element modelis also established for displacement responses using ABAQUS.The comparison with the results of the finite-element modelshows that the results of the proposed discrete modelare available.
基金Under the auspices of National Natural Science Foundation of China (No. 41001112,40635028)
文摘Through a case study of Shenzhen City,China,this study focused on a quantitative method for analyzing the spatial processes involved in green infrastructure changes associated with rapid urbanization.Based on RS,GIS and SPSS statistics software,the approach includes selection of the square analysis units and representative landscape metrics,quantification of the change types of landscape metrics in all analysis units through two indices and hierarchical cluster analysis of the above analysis units with different landscape metric change types(i.e.spatial attributes).The analyses verify that there is a significant sequence of continuous changes in green infrastructure in Shenzhen.They are the perforation,the segmentation,the fragmentation,the evanescence and the filling-in processes,which have a good spatio-temporal correspondence with urbanization and reflect the synthetic influence of urban planning,government policies and landforms.Compared with other studies on quantifying the spatial pattern,this study provides an alternative probe into linking the spatial pattern to spatial processes and the corresponding ecological processes in the future.These spatio-temporal processes offer many opportunities for identifying,protecting and restoring key elements in an urban green infrastructure network for areas in the early stages of urbanization or for non-urbanized areas.
基金supported by the National Hi-tech Research and Development Program of China(No. 2009AA12Z147)the Postdoctorial Foundation of China(No.20090451339)+2 种基金the Postdoctorial Foundation of Shandong Province(No.200802013)Soft Science Project of Shandong Province(No.2007 RKA071)this research is also supported by Qingdao Economic & Technical Developing District Project (No.2008-2-26).
文摘The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chosen to calculate the environmental geochemical baseline.The geoaccumulation index was calculated and mapped to indicate the environmental quality of the soil.The results show that the urban areas are barely polluted with Ni and Cr but the rural areas in the southern part of the city, and the western part of the lake,are polluted with Ni,Cr,and Cu at the second level.On the other hand,the rural areas in the southern part of the city,and the western part of the lake,are polluted with As at a moderate level.The other area is polluted at the second level.An increase in As pollution occurs in a direction from northeast to southwest.The Cd pollution follows a trend similar to As,with an additional smaller contaminated area polluted at levelⅢ.The Hg pollution typical of urban areas occurs in the main and northern parts of the city.The geochemical accumulation index decreases from the city center to the periphery.The highest pollution level reaches levelⅣ,which indicates that the soil is seriously polluted with Hg.The southern part of the city and the rural areas to the west of the lake are not contaminated with Hg.Geological factors and the disturbance from human activities are both possible major factors:further research is needed to identify them.
基金Funded by Key Project of the Natural Science Foundation of China under the grant No. 40635026.
文摘As a typical car-dependent city, Los Angeles (LA) is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA's geologic conditions and civil circumstances, we argued that the relationship between LA's low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Off reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short constrnction-period projects enabled fast establishment of LA's highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China's motorization and urban development, we found that the trajectory of Beijing's motorization between 197g and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA's urban and transportation development should be suggestive to China's urban and transportation planning.
文摘This paper analyses the composition, the overall importance of city infrastructure construction and promote the city in the process of meaning. Then analysis the importance of city traffic infrastructure construction, the vanity of the city infrastructure and social infrastructure in the process of city, and puts forward relying on infrastructure construction to promote the urbanization development strategy.
文摘The proper amount, the suitable structure and the tentative sources of urban infrastructure investment are the main focuses of urban policy makers. Firstly the amount of urban infrastructure investment is combinatory forecasted based on historical statistic databases of China. Then the interrelationship of urban infrastructure investment with GNP and the whole society investment in fixed assets are analyzed to work out quantitative coherent relationship. Finally the paper analyses the present and the future development trends of investment structure and capital resource respectively.
基金Part achievements ofkey projectofthe firstscience and research fund in Mianyang Normal University.
文摘According to the characteristics of the primary materials of the basic land price in the little town, the author uses the analysis function of the figures and the space to set off the rank unit,calculate the numberof the unit and rank the land. The method and the system of the evaluation of the basic land price in the little town (especially the little towns in the Western China) will be perfect.
文摘Adopting the BOT (build-operate-transfer) delivery method has brought opportunities and challenges in construction time and quality for urban infrastructure. Many studies investigate the upstream issues of BOT projects such as concessionaire selection criteria and risk factors. But the project execution becomes complicated such as the escalated quality supervision organization and procedure at the construction stage. This extra supervision may have constituted hidden redundancies as waste to economic sustainability. This paper investigated construction quality supervision of BOT projects to pinpoint adequate degree of supervision and detect redundant organization and procedures. The study adopted ten subway construction projects as cases in which five were from the traditional design-bid-build (DBB) and five from the BOT methods. Thirty six project participants including owners, contractors, designers, and concessionaire managers of the ten projects were interviewed to tell their views on these issues. The quality supervision measures of the DBB projects were used as the baseline and compared with those of the BOT projects. The research results show that the construction quality seems no difference for the DBB and BOT projects. Construction quality comes out of supervision but excessive supervision organization and procedures do not necessarily improve quality. This finding indicates that adequate degree of supervision is enough to achieve required quality to save immense paperwork for large construction projects.
基金Under the auspices of National Natural Science Foundation of China(No.41571130,41271165,41701177)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(No.[2015]1098)The Fundamental Research Funds for the Central Universities,Collaborative Innovation Center for Geopolitical setting of Southwest China and Borderland Development(YNNU)
文摘In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localized perspective, ‘administrative urbanization', can provide a contextual explanation for the mechanism of urbanization in the reform era. The case study of Ordos indicates that new town construction, especially in the inland area, has become the main strategy for investment attraction and economic development. The local government has played a dominant role in this construction through a series of administrative measures, including avoidance of central state regulations, land leasing, high standard infrastructure construction, relocation policies and industrial attraction. This article also explores the issue of unsustainability in the new town, and identifies that underdeveloped industrialization, slow population agglomeration and real estate bubbles are primary threats to the sustainability of administrative urbanization.
文摘Landslides are one of the most widespread and dangerous phenomena in the urbanized territories. In Moscow they affect about 3% of the most valuable territory, including churches and historical buildings located at high banks of the Moskva River. Recently the landslide activation occurred. Normal functioning of city infrastructure and implementation of effective slope protection measures require special landslide monitoring. Mechanical-mathematical model of high viscous fluid was applied for the landslide-prone slopes modeling. Equation of continuityand an approximatedNavier-Stockes equation f or slow motions in a thin layer were used. The results of modelling give possibility to define the landslide section with upmost velocity that should be monitored in the first place. Some important parameters used for numerical modelling can be defined from monitoring data.
基金supported by the National Basic Research Program of China (Grant no. 2005CB724206)the project of Master Plan of Yutian xian 2003–2020
文摘To analyze China’s actual urbanization level, we iden- tified two statistical approaches: using the population living within the administrative boundaries ("administrative-based" method) and within the urbanized or built-up areas ("infrastructure-based" method) of cities and towns as urban population. To illustrate the two approaches and the associated problems, we used data for Tangshan City as a case study. The estimates on the "administrative-based" method were unreliable and the "infrastructurebased" method provided a 29.4% urbanization rate for Tangshan City in 2002, which is lower than the mean of 36.1% for China as a whole published after the fifth national census in 2000. Given the city’s geographic location, comprehensive urban construction and economic development indicators, its urbanization rate should be higher than the average level. Thus, our results indicate that the value of 36.1% was higher than the actual status as a result of poor statistical quality and overestimation of the floating population.
文摘There is a high potential for small-scale and medium scale wood-fired cogeneration in Estonia. The purpose of this research is to define the eligible capacity for wood fuel based cogeneration plant operating on the base of district heating systems in small towns. Results were checked and approbated by economical and environmental factors. Two optimal sizing methods were used maximizing of amount of heat year-round while working at full installed capacity and maximizing of amount of heat year-round while working with partial loads. Results of defining optimal capacities for wood-fired cogeneration plants in small Estonian towns showed that method of maximizing of amount of heat year-round while working with partial loads is more adequate to real situation.
文摘The article analyzes the current situation of city infrastructure construction in China, elaborated needs if our country city infrastructure construction projects in various stages of information management, a framework of information platform are presented for city infrastructure projects of our construction comprehensive control, and efficient management city infrastructure construction project, and provide collaboration platform for the party in the infrastructure construction projects.
文摘City development is a result of many factors, of which land value is one of the major determinants. The past urban economics studies have shown that land value is largely determined by location factors such as distance from Central Business District (CBD) ignoring the non-location factors like time of purchase and neighbourhood infrastructures. Therefore, this paper attempts to establish the relative importance of location and non-location factors in the determination of residential land value by positing Onitsha, Nigeria as a case study. Eight hundred and fifty residential housing units were selected and questionnaire administered to the landlords through multi-stage sampling technique. The stepwise regression analysis results showed that non-location factors, especially, time of land purchase, contribute more to the variation in residential land values. The paper suggests the revision of the classical economic theories to represent the conditions of urban areas in developing countries .