In the present study,the complete genomes of four common（4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014）and two virulent（11/EV71/Wenzhou/CHN/2014and 109/EV7...In the present study,the complete genomes of four common（4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014）and two virulent（11/EV71/Wenzhou/CHN/2014and 109/EV71/Wenzhou/CHN/2014）enterovirus 71（EV71）isolates were sequenced and described.They are 7405 bp in length and belong to EV71 sub-genotype C4 （C4a cluster）.展开更多
Incidence of Armillaria infection was quantified based on site factors in New Zealand Pinus radiata plantations.A linear multiple regression model was derived to predict infection levels of Armillaria root rot.Factors...Incidence of Armillaria infection was quantified based on site factors in New Zealand Pinus radiata plantations.A linear multiple regression model was derived to predict infection levels of Armillaria root rot.Factors positivily associated with the infection were:previous vegetation（native bush,pine）;soil type（pumice）;landform （valley,gully,flat）and the interaction between them.This model could assist in management planning with regard to the predisposition of particular stand to Armillaria infection.Keywods:Armillaria root rot,Disease incidence,Site factors,Quantification,Pinus radiata.展开更多
The Guangfucun Site is located in thewest of Taoyuan Town,Wujiang City,the furthest south end of JiagsuProvince.It is a Neolithic site datedto 6055±125 BP.The cultural de-posits belong to the Majiabang Cul-ture.T...The Guangfucun Site is located in thewest of Taoyuan Town,Wujiang City,the furthest south end of JiagsuProvince.It is a Neolithic site datedto 6055±125 BP.The cultural de-posits belong to the Majiabang Cul-ture.This paper reported the resultsof plant opal analysis of the site and展开更多
Utilizing energy storage in depleted oil and gas reservoirs can improve productivity while reducing power costs and is one of the best ways to achieve synergistic development of"Carbon Peak–Carbon Neutral"a...Utilizing energy storage in depleted oil and gas reservoirs can improve productivity while reducing power costs and is one of the best ways to achieve synergistic development of"Carbon Peak–Carbon Neutral"and"Underground Resource Utiliza-tion".Starting from the development of Compressed Air Energy Storage(CAES)technology,the site selection of CAES in depleted gas and oil reservoirs,the evolution mechanism of reservoir dynamic sealing,and the high-flow CAES and injection technology are summarized.It focuses on analyzing the characteristics,key equipment,reservoir construction,application scenarios and cost analysis of CAES projects,and sorting out the technical key points and existing difficulties.The devel-opment trend of CAES technology is proposed,and the future development path is scrutinized to provide reference for the research of CAES projects in depleted oil and gas reservoirs.展开更多
Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used l...Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land （including residential land and other construction land）, and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 ： 5.6 ： 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.展开更多
As the preferred nitrogen(N)source,ammonium(NH_(4)^(+))contributes to plant growth and development and fruit quality.In plants,NH 4+uptake is facilitated by a family of NH_(4)^(+) transporters(AMT).However,the molecul...As the preferred nitrogen(N)source,ammonium(NH_(4)^(+))contributes to plant growth and development and fruit quality.In plants,NH 4+uptake is facilitated by a family of NH_(4)^(+) transporters(AMT).However,the molecular mechanisms and functional characteristics of the AMT genes in peach have not been mentioned yet.In this present study,excess NH_(4)^(+) stress severely hindered shoot growth and root elongation,accompanied with reduced mineral accumulation,decreased leaf chlorophyll concentration,and stunned photosynthetic performance.In addition,we identified 14 putative AMT genes in peach(PpeAMT).Expression analysis showed that PpeAMT genes were differently expressed in peach leaves,stems and roots,and were distinctly regulated by external NH_(4)^(+) supplies.Putative cis-elements involved in abiotic stress adaption,Ca^(2+) response,light and circadian rhythms regulation,and seed development were observed in the promoters of the PpeAMT family genes.Phosphorylation analysis of residues within the C-terminal of PpeAMT proteins revealed many conserved phosphorylation residues in both the AMT1 and AMT2 subfamily members,which could potentially play roles in controlling the NH 4+transport activities.This study provides gene resources to study the biological function of AMT proteins in peach,and reveals molecular basis for NH_(4)^(+) uptake and N nutrition mechanisms of fruit trees.展开更多
In this manuscript we present a nonlinear site amplification model for ground-motion prediction equations(GMPEs)in Japan,using a site period-based site class and a site impedance ratio as site parameters.We used a lar...In this manuscript we present a nonlinear site amplification model for ground-motion prediction equations(GMPEs)in Japan,using a site period-based site class and a site impedance ratio as site parameters.We used a large number of shear-wave velocity profiles from the Kiban-Kyoshin network(KiK-net)and the Kyoshin network(K-NET)to construct the one-dimensional(1D)numerical models.The strong-motion records from rock-sites in Japan with different earthquake categories and taken from the Pacific Earthquake Engineering Research Center dataset were used in this study.We fit a set of 1D site amplification models using the spectral amplification ratios derived from 1D equivalent linear analyses.Parameters of site impedance ratios for both linear and nonlinear site response were included in the 1D model.The 1D model could be implemented into GMPEs using a new proposed adjustment method.The adjusted site amplification ratios retain the nonlinear characteristics of the 1D model for strong motions and match the linear amplification ratio in GMPE for weak motions.The nonlinearity of the present site model is reasonably similar to that of the historical models,and the present site model could satisfactorily capture the nonlinear site response in empirical data.展开更多
Surface ground motion produced by underground blasts is significantly influenced by near-surface geological conditions.However,near-surface low-propagation velocity layers were always ignored in past analyses of groun...Surface ground motion produced by underground blasts is significantly influenced by near-surface geological conditions.However,near-surface low-propagation velocity layers were always ignored in past analyses of ground motions due to their thin thickness.With the rising concern about surface ground motions produced by the ascendant scale and frequentness of underground excavation and mining,close attention is gradually paid to ground blast vibrations.Therefore,systemic experiments were conducted and took seven months in an underground mine to clarify the variation of motion from underground rock to surface ground.The attenuation of surface ground peak particle velocities(PPVs)is compared to that in underground rock,and horizontal amplitudes are compared to vertical amplitudes.Differences between bedrock and surface ground vibrations are analyzed to illustrate the site effect of near-surface lower-propagation velocity layers.One-dimensional site response analysis is employed to quantify the influence of different geological profiles on surface ground vibrations.The experimental data and site response analysis allowed the following conclusions:(1)geological site effects mainly produce decreasing dominant frequency(DF)of surface ground vibrations;(2)the site amplification effect of blast vibration needs to be characterized by peak particle displacement(PPD);(3)shear waves(S-waves)begin to dominate and surface Rayleigh waves(R-waves)develop as blast-induced ground vibrations travel upward through rock and lower-velocity layers to the surface.The comparison of response relative displacement to a critical value is best to assess the potential for cracking on surface structures.展开更多
The recrpstallization texture evolution of an interstitial-free (IF) sheet steel dumngannealing is modellcd by Monte Carlo method. A new approach to the problem ofgraln impingement in modelling the development of recr...The recrpstallization texture evolution of an interstitial-free (IF) sheet steel dumngannealing is modellcd by Monte Carlo method. A new approach to the problem ofgraln impingement in modelling the development of recrystallization texture is fullydescri6ed, which is based on detailed site analysis and the introduction of proba6ilityvalue Pij for the tro nsition between dtherently oriented groins. As an illustmtive case.the theory of orlented nucleation and two critical sizes of nuclei are selected to modelthe mechanism of recrystallization texture formation. The results simulated for severalrepresentative texture components are in agreement with the known experiments.展开更多
The objective of this study is to define park design standards,determine the user expectations of the parks and evaluate the defined standards in the case of Taraqi Park in Herat city.On-site detection,observation and...The objective of this study is to define park design standards,determine the user expectations of the parks and evaluate the defined standards in the case of Taraqi Park in Herat city.On-site detection,observation and questionnaire survey methods were utilized in the study.The conformity of the park area with international standards were evaluated while general satisfaction towards the park was tried to be determined by virtue of surveys made with the users of the park.The results revealed that the current status of the park was poor,design and management of the park needs urgent improvements.Taraqi Park is the most visited park of the city in which the overall design of the park,facilities,management and maintenance systems are observed inadequate according to standards,rules and regulations of urban parks.展开更多
A new form of producing and sharing knowledge has emerged as an international(United States of America,Asia,and Europe) research collaboration,known as the Long-Term Ecological Research(LTER) Network.Although Africa b...A new form of producing and sharing knowledge has emerged as an international(United States of America,Asia,and Europe) research collaboration,known as the Long-Term Ecological Research(LTER) Network.Although Africa boasts rich biodiversity,including endemic species,it lacks the long-term initiatives to underpin sustainable biodiversity managements.At present,climate change may exacerbate hunger and poverty concerns in addition to resulting in ecosystem degradation,land use change,and other threats in Africa.Therefore,ecosystem monitoring was suggested to understanding the effects of climate change and setting strategies to mitigate these changes.This paper aimed to investigate ecosystem monitoring ground sites and address their coverage gaps in Africa to provide a foundation for optimizing the African Ecosystem Research Network(AERN) ground sites.The geographic coordinates and characteristics of ground sites-based ecosystem monitoring were collected from various networks aligned with the LTER implementation in Africa.Additionally,climatic data and biodiversity distribution maps were retrieved from various sources.These data were used to assess the size of existing ground sites and the gaps in description,ecosystems and biomes.The results reveal that there were 1089 sites established by various networks.Among these sites,30.5%,27.5%,and 28.8% had no information of area,year of establishment,current status,respectively.However,68.0% of them had an area equal to or greater than 1 km2.Sites were created progressively over the course of the years,with 68.9% being created from 2000 to 2005.To date,only 41.5% of the sites were operational.The sites were scattered across Africa,but they were concentrated in Eastern and Southern Africa.The unbalanced distribution pattern of the sites left Central and Northern Africa hardly covered,and many unique ecosystems in Central Africa were not included.To sustain these sites,the AERN should be based on operational sites,seeking secure funding by establishing multiple partnerships.展开更多
Site conditions,including geotechnical properties and the geological setting,influence the near-surface response of strata subjected to seismic excitation.The geotechnical parameters required for the design of foundat...Site conditions,including geotechnical properties and the geological setting,influence the near-surface response of strata subjected to seismic excitation.The geotechnical parameters required for the design of foundations include mass density(ρ),damping ratio(β_(s)),shear wave velocity(V_(s)),and soil shear modulus(G_(s)).The values of the last three parameters are sensitive to the level of nonlinear strain induced in the strata due to seismic ground motion.In this study,the effect of variations in soil properties,such as plasticity index(PI),effective stress(σ′),over consolidation ratio(OCR),impedance contrast ratio(ICR)between the bedrock and the overlying strata,and depth of soil strata over bedrock(H),on seismic design parameters(β_(s),V_(s),and G_(s))was investigated for National Earthquake Hazards Reduction Program(NEHRP)site classes C and D,through 1D nonlinear seismic site response analysis.The Morris one-at-a-time(OAT)sensitivity analysis indicated thatβ_(s),V_(s),and G_(s)were significantly influenced by variations in PI,while ICR affectedβ_(s)more than it affected V_(s)and G_(s).However,the influence of H on these parameters was less significant.It was also found that variations in soil properties influenced seismic design parameters in soil type D more significantly than in soil type C.Predictive relationships forβ_(s),V_(s),and G_(s)were derived based on the 1D seismic site response analysis and sensitivity analysis results.Theβ_(s),V_(s),and G_(s)values obtained from the analysis were compared with the corresponding values in NEHRP to determine the similarities and differences between the two sets of values.The need to incorporate PI and ICR in the metrics for determiningβ_(s),V_(s),and G_(s)for the seismic design of foundations was highlighted.展开更多
Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice padd...Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites(28 rice paddies and 42 dry croplands).The data set covered 16 dominant soil types found in croplands across 23 provinces of China's Mainland.The fertilization schemes were grouped into six categories:N(inorganic nitrogen fertilizer only),NP(compound inorganic nitrogen and phosphorus fertilizers),NPK(compound inorganic nitrogen,phosphorus and potassium fertilizers),O(organic fertilizers only),OF(combined inorganic/organic fertilization) and Others(other unbalanced fertilizations such as P only,K only,P plus K and N plus K).Relative change in SOC content was analyzed,and rice paddies and dry croplands soils were compared.There was an overall temporal increase in topsoil SOC content,and relative annual change(RAC,g kg-1 yr-1) ranged -0.14-0.60(0.13 on average) for dry cropland soils and -0.12-0.70(0.19 on average) for rice paddies.SOC content increase was higher in rice paddies than in dry croplands.SOC increased across experimental sites,but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.SOC increase was higher under balanced chemical fertilizations with compound N,P and K fertilizers than unbalanced fertilizations such as N only,N plus P,and N plus K.The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies,although RAC values decreased generally as the experiment duration increased.Therefore,the extension of rational fertilization in China's croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.展开更多
It is difficult to rapidly and on-line detect trace volatile organic compounds for miniature massspectrometry due to its limited sampling volume at slow pumping speed. In this paper, we developed anew radiofrequency f...It is difficult to rapidly and on-line detect trace volatile organic compounds for miniature massspectrometry due to its limited sampling volume at slow pumping speed. In this paper, we developed anew radiofrequency field enhanced chemical ionization source （RF-ECI） with vacuum ultraviolet （VUV）lamp by coupling radiofrequency electric field and direct-current field together. The experiment resultsshowed that the sensitivity of benzene, toluene, hydrogen sulfide and other compounds increased by 2-3orders of magnitude under the introduction of RF-ECI comparing to traditional single photon ionization（SPI）. At the same time, the reagent ion of O2＋ realized the charge transfer reaction chemical ionization,and the RF-ECI effectively expanded the detection range of the VUV lamp based SPI. The VUV lamp hasinherent advantages in the on-site analytical instrument for its small size and low power consumption,and the VUV lamp based RF-ECI miniature time-of-flight mass spectrometer （TOFMS） has a limit-of-detection for H2S as low as 0.0571 mg/m3, and it is expected to be used widely in the field of on-site rapidanalvsis.展开更多
In this study,a model based on multiple regression analysis is developed to forecast the tourism traffic volume of theme parks.First,the macro,meso and micro factors affecting traffic passenger volume are analysed.Sec...In this study,a model based on multiple regression analysis is developed to forecast the tourism traffic volume of theme parks.First,the macro,meso and micro factors affecting traffic passenger volume are analysed.Second,SPSS software is used for multivariate regression analysis on data for 10 theme parks from 2014.A tourism traffic volume forecasting model is then proposed.Finally,related data for 2015 is used to validate the model,with results showing a prediction error of 14.1%.All results show that the model has a high predictive ability.展开更多
Fear of liability from the 1980 Comprehensive Environmental Response,Compensation,and Liability Act(CERCLA or Superfund)has prompted developers to build preferentially upon undeveloped green space rather than potentia...Fear of liability from the 1980 Comprehensive Environmental Response,Compensation,and Liability Act(CERCLA or Superfund)has prompted developers to build preferentially upon undeveloped green space rather than potentially contaminated former industrial sites,leading to urban sprawl in the suburban areas while blighted properties in the urban core remain vacant.A brownfield is defined as a property in which the presence or potential presence of a hazardous substance or contaminant poses a barrier to development.Agencies often create brownfield inventories by performing a site suitability analysis,using distinguishing features such as ecolo-gically and culturally significant areas or neighborhoods that need revitalizing.Pima County,Arizona and the Sonora Environmental Research Institute,Inc.(SERI)developed a brownfield inventory of the large,industrial area directly to the west of Davis-Monthan Air Force Base.Because the brownfield target area has few residential neighborhoods and lacks the distinguish-ing features usually used in a brownfield site suitability analysis,the county and SERI used the official tax assessor database and 11 federal,state and county environmental databases to develop a brownfield inventory.The goal of the project was to prioritize properties that stood to benefit from the grant funding.The final brownfield inventory contained 531 parcels.展开更多
基金funded by Natural Science Foundation of Zhejiang(LQ14C010006)National Natural Science Foundation of China(81501363)Planned Science and Technology Project of Zhejiang(2014C33261)
文摘In the present study,the complete genomes of four common（4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014）and two virulent（11/EV71/Wenzhou/CHN/2014and 109/EV71/Wenzhou/CHN/2014）enterovirus 71（EV71）isolates were sequenced and described.They are 7405 bp in length and belong to EV71 sub-genotype C4 （C4a cluster）.
文摘Incidence of Armillaria infection was quantified based on site factors in New Zealand Pinus radiata plantations.A linear multiple regression model was derived to predict infection levels of Armillaria root rot.Factors positivily associated with the infection were:previous vegetation（native bush,pine）;soil type（pumice）;landform （valley,gully,flat）and the interaction between them.This model could assist in management planning with regard to the predisposition of particular stand to Armillaria infection.Keywods:Armillaria root rot,Disease incidence,Site factors,Quantification,Pinus radiata.
文摘The Guangfucun Site is located in thewest of Taoyuan Town,Wujiang City,the furthest south end of JiagsuProvince.It is a Neolithic site datedto 6055±125 BP.The cultural de-posits belong to the Majiabang Cul-ture.This paper reported the resultsof plant opal analysis of the site and
基金the financial support from the Scientific Research and Technology Development Project of China Energy Engineering Corporation Limited(CEEC-KJZX-04).
文摘Utilizing energy storage in depleted oil and gas reservoirs can improve productivity while reducing power costs and is one of the best ways to achieve synergistic development of"Carbon Peak–Carbon Neutral"and"Underground Resource Utiliza-tion".Starting from the development of Compressed Air Energy Storage(CAES)technology,the site selection of CAES in depleted gas and oil reservoirs,the evolution mechanism of reservoir dynamic sealing,and the high-flow CAES and injection technology are summarized.It focuses on analyzing the characteristics,key equipment,reservoir construction,application scenarios and cost analysis of CAES projects,and sorting out the technical key points and existing difficulties.The devel-opment trend of CAES technology is proposed,and the future development path is scrutinized to provide reference for the research of CAES projects in depleted oil and gas reservoirs.
基金Under the auspices of National Natural Science Foundation of China(No.41130526)Beijing Municipal Natural Science Foundation(No.8122020)
文摘Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land （including residential land and other construction land）, and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 ： 5.6 ： 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.
基金This work was supported by the National Key R&D Program of China(2019YFD1000500,2016YFD0600106)China Agriculture Research System(CARS-29-16),the Agricultural Variety Improvement Project of Shandong Province(2019LZGC009)the Key R&D Program of Shandong Province(GG201809260221,2019GSF1070952,018JHZ006).
文摘As the preferred nitrogen(N)source,ammonium(NH_(4)^(+))contributes to plant growth and development and fruit quality.In plants,NH 4+uptake is facilitated by a family of NH_(4)^(+) transporters(AMT).However,the molecular mechanisms and functional characteristics of the AMT genes in peach have not been mentioned yet.In this present study,excess NH_(4)^(+) stress severely hindered shoot growth and root elongation,accompanied with reduced mineral accumulation,decreased leaf chlorophyll concentration,and stunned photosynthetic performance.In addition,we identified 14 putative AMT genes in peach(PpeAMT).Expression analysis showed that PpeAMT genes were differently expressed in peach leaves,stems and roots,and were distinctly regulated by external NH_(4)^(+) supplies.Putative cis-elements involved in abiotic stress adaption,Ca^(2+) response,light and circadian rhythms regulation,and seed development were observed in the promoters of the PpeAMT family genes.Phosphorylation analysis of residues within the C-terminal of PpeAMT proteins revealed many conserved phosphorylation residues in both the AMT1 and AMT2 subfamily members,which could potentially play roles in controlling the NH 4+transport activities.This study provides gene resources to study the biological function of AMT proteins in peach,and reveals molecular basis for NH_(4)^(+) uptake and N nutrition mechanisms of fruit trees.
基金National Science Foundation of China under Grant No.51578470。
文摘In this manuscript we present a nonlinear site amplification model for ground-motion prediction equations(GMPEs)in Japan,using a site period-based site class and a site impedance ratio as site parameters.We used a large number of shear-wave velocity profiles from the Kiban-Kyoshin network(KiK-net)and the Kyoshin network(K-NET)to construct the one-dimensional(1D)numerical models.The strong-motion records from rock-sites in Japan with different earthquake categories and taken from the Pacific Earthquake Engineering Research Center dataset were used in this study.We fit a set of 1D site amplification models using the spectral amplification ratios derived from 1D equivalent linear analyses.Parameters of site impedance ratios for both linear and nonlinear site response were included in the 1D model.The 1D model could be implemented into GMPEs using a new proposed adjustment method.The adjusted site amplification ratios retain the nonlinear characteristics of the 1D model for strong motions and match the linear amplification ratio in GMPE for weak motions.The nonlinearity of the present site model is reasonably similar to that of the historical models,and the present site model could satisfactorily capture the nonlinear site response in empirical data.
基金supported by Natural Science Foundation of Jiangsu Province,China(Grant No.BK20220975)the National Natural Science Foundation of China(Grant Nos.51874350 and 41807259).
文摘Surface ground motion produced by underground blasts is significantly influenced by near-surface geological conditions.However,near-surface low-propagation velocity layers were always ignored in past analyses of ground motions due to their thin thickness.With the rising concern about surface ground motions produced by the ascendant scale and frequentness of underground excavation and mining,close attention is gradually paid to ground blast vibrations.Therefore,systemic experiments were conducted and took seven months in an underground mine to clarify the variation of motion from underground rock to surface ground.The attenuation of surface ground peak particle velocities(PPVs)is compared to that in underground rock,and horizontal amplitudes are compared to vertical amplitudes.Differences between bedrock and surface ground vibrations are analyzed to illustrate the site effect of near-surface lower-propagation velocity layers.One-dimensional site response analysis is employed to quantify the influence of different geological profiles on surface ground vibrations.The experimental data and site response analysis allowed the following conclusions:(1)geological site effects mainly produce decreasing dominant frequency(DF)of surface ground vibrations;(2)the site amplification effect of blast vibration needs to be characterized by peak particle displacement(PPD);(3)shear waves(S-waves)begin to dominate and surface Rayleigh waves(R-waves)develop as blast-induced ground vibrations travel upward through rock and lower-velocity layers to the surface.The comparison of response relative displacement to a critical value is best to assess the potential for cracking on surface structures.
文摘The recrpstallization texture evolution of an interstitial-free (IF) sheet steel dumngannealing is modellcd by Monte Carlo method. A new approach to the problem ofgraln impingement in modelling the development of recrystallization texture is fullydescri6ed, which is based on detailed site analysis and the introduction of proba6ilityvalue Pij for the tro nsition between dtherently oriented groins. As an illustmtive case.the theory of orlented nucleation and two critical sizes of nuclei are selected to modelthe mechanism of recrystallization texture formation. The results simulated for severalrepresentative texture components are in agreement with the known experiments.
文摘The objective of this study is to define park design standards,determine the user expectations of the parks and evaluate the defined standards in the case of Taraqi Park in Herat city.On-site detection,observation and questionnaire survey methods were utilized in the study.The conformity of the park area with international standards were evaluated while general satisfaction towards the park was tried to be determined by virtue of surveys made with the users of the park.The results revealed that the current status of the park was poor,design and management of the park needs urgent improvements.Taraqi Park is the most visited park of the city in which the overall design of the park,facilities,management and maintenance systems are observed inadequate according to standards,rules and regulations of urban parks.
基金Under the auspices of National Natural Science Foundation of China(No.31161140355)
文摘A new form of producing and sharing knowledge has emerged as an international(United States of America,Asia,and Europe) research collaboration,known as the Long-Term Ecological Research(LTER) Network.Although Africa boasts rich biodiversity,including endemic species,it lacks the long-term initiatives to underpin sustainable biodiversity managements.At present,climate change may exacerbate hunger and poverty concerns in addition to resulting in ecosystem degradation,land use change,and other threats in Africa.Therefore,ecosystem monitoring was suggested to understanding the effects of climate change and setting strategies to mitigate these changes.This paper aimed to investigate ecosystem monitoring ground sites and address their coverage gaps in Africa to provide a foundation for optimizing the African Ecosystem Research Network(AERN) ground sites.The geographic coordinates and characteristics of ground sites-based ecosystem monitoring were collected from various networks aligned with the LTER implementation in Africa.Additionally,climatic data and biodiversity distribution maps were retrieved from various sources.These data were used to assess the size of existing ground sites and the gaps in description,ecosystems and biomes.The results reveal that there were 1089 sites established by various networks.Among these sites,30.5%,27.5%,and 28.8% had no information of area,year of establishment,current status,respectively.However,68.0% of them had an area equal to or greater than 1 km2.Sites were created progressively over the course of the years,with 68.9% being created from 2000 to 2005.To date,only 41.5% of the sites were operational.The sites were scattered across Africa,but they were concentrated in Eastern and Southern Africa.The unbalanced distribution pattern of the sites left Central and Northern Africa hardly covered,and many unique ecosystems in Central Africa were not included.To sustain these sites,the AERN should be based on operational sites,seeking secure funding by establishing multiple partnerships.
基金This work was supported by Kuwait University,Research Grant No.EV01/15.
文摘Site conditions,including geotechnical properties and the geological setting,influence the near-surface response of strata subjected to seismic excitation.The geotechnical parameters required for the design of foundations include mass density(ρ),damping ratio(β_(s)),shear wave velocity(V_(s)),and soil shear modulus(G_(s)).The values of the last three parameters are sensitive to the level of nonlinear strain induced in the strata due to seismic ground motion.In this study,the effect of variations in soil properties,such as plasticity index(PI),effective stress(σ′),over consolidation ratio(OCR),impedance contrast ratio(ICR)between the bedrock and the overlying strata,and depth of soil strata over bedrock(H),on seismic design parameters(β_(s),V_(s),and G_(s))was investigated for National Earthquake Hazards Reduction Program(NEHRP)site classes C and D,through 1D nonlinear seismic site response analysis.The Morris one-at-a-time(OAT)sensitivity analysis indicated thatβ_(s),V_(s),and G_(s)were significantly influenced by variations in PI,while ICR affectedβ_(s)more than it affected V_(s)and G_(s).However,the influence of H on these parameters was less significant.It was also found that variations in soil properties influenced seismic design parameters in soil type D more significantly than in soil type C.Predictive relationships forβ_(s),V_(s),and G_(s)were derived based on the 1D seismic site response analysis and sensitivity analysis results.Theβ_(s),V_(s),and G_(s)values obtained from the analysis were compared with the corresponding values in NEHRP to determine the similarities and differences between the two sets of values.The need to incorporate PI and ICR in the metrics for determiningβ_(s),V_(s),and G_(s)for the seismic design of foundations was highlighted.
基金supported by the National Natural Science Foundation of China (Grant No. 40710019002)the Ministry of Science and Technology of China (Grant No. 2008BAD95B13-1)the Ministry of Education of China for key basic research projects
文摘Topsoil soil organic carbon(SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006.The data set comprised 481 observations(135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites(28 rice paddies and 42 dry croplands).The data set covered 16 dominant soil types found in croplands across 23 provinces of China's Mainland.The fertilization schemes were grouped into six categories:N(inorganic nitrogen fertilizer only),NP(compound inorganic nitrogen and phosphorus fertilizers),NPK(compound inorganic nitrogen,phosphorus and potassium fertilizers),O(organic fertilizers only),OF(combined inorganic/organic fertilization) and Others(other unbalanced fertilizations such as P only,K only,P plus K and N plus K).Relative change in SOC content was analyzed,and rice paddies and dry croplands soils were compared.There was an overall temporal increase in topsoil SOC content,and relative annual change(RAC,g kg-1 yr-1) ranged -0.14-0.60(0.13 on average) for dry cropland soils and -0.12-0.70(0.19 on average) for rice paddies.SOC content increase was higher in rice paddies than in dry croplands.SOC increased across experimental sites,but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.SOC increase was higher under balanced chemical fertilizations with compound N,P and K fertilizers than unbalanced fertilizations such as N only,N plus P,and N plus K.The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies,although RAC values decreased generally as the experiment duration increased.Therefore,the extension of rational fertilization in China's croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.
基金financially supported by the National Natural Science Foundation of China(Nos.21375129 and 21675155)
文摘It is difficult to rapidly and on-line detect trace volatile organic compounds for miniature massspectrometry due to its limited sampling volume at slow pumping speed. In this paper, we developed anew radiofrequency field enhanced chemical ionization source （RF-ECI） with vacuum ultraviolet （VUV）lamp by coupling radiofrequency electric field and direct-current field together. The experiment resultsshowed that the sensitivity of benzene, toluene, hydrogen sulfide and other compounds increased by 2-3orders of magnitude under the introduction of RF-ECI comparing to traditional single photon ionization（SPI）. At the same time, the reagent ion of O2＋ realized the charge transfer reaction chemical ionization,and the RF-ECI effectively expanded the detection range of the VUV lamp based SPI. The VUV lamp hasinherent advantages in the on-site analytical instrument for its small size and low power consumption,and the VUV lamp based RF-ECI miniature time-of-flight mass spectrometer （TOFMS） has a limit-of-detection for H2S as low as 0.0571 mg/m3, and it is expected to be used widely in the field of on-site rapidanalvsis.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY15E080008)the National Natural Science Foundation of China(Grant No.50908205).
文摘In this study,a model based on multiple regression analysis is developed to forecast the tourism traffic volume of theme parks.First,the macro,meso and micro factors affecting traffic passenger volume are analysed.Second,SPSS software is used for multivariate regression analysis on data for 10 theme parks from 2014.A tourism traffic volume forecasting model is then proposed.Finally,related data for 2015 is used to validate the model,with results showing a prediction error of 14.1%.All results show that the model has a high predictive ability.
基金The project was funded by the United States Environmental Protection Agency through Brownfields Assessment Grant#BF-99T36101 Additional funding was provided by the Sonora Environmental Research Institute,Inc.(SERI).
文摘Fear of liability from the 1980 Comprehensive Environmental Response,Compensation,and Liability Act(CERCLA or Superfund)has prompted developers to build preferentially upon undeveloped green space rather than potentially contaminated former industrial sites,leading to urban sprawl in the suburban areas while blighted properties in the urban core remain vacant.A brownfield is defined as a property in which the presence or potential presence of a hazardous substance or contaminant poses a barrier to development.Agencies often create brownfield inventories by performing a site suitability analysis,using distinguishing features such as ecolo-gically and culturally significant areas or neighborhoods that need revitalizing.Pima County,Arizona and the Sonora Environmental Research Institute,Inc.(SERI)developed a brownfield inventory of the large,industrial area directly to the west of Davis-Monthan Air Force Base.Because the brownfield target area has few residential neighborhoods and lacks the distinguish-ing features usually used in a brownfield site suitability analysis,the county and SERI used the official tax assessor database and 11 federal,state and county environmental databases to develop a brownfield inventory.The goal of the project was to prioritize properties that stood to benefit from the grant funding.The final brownfield inventory contained 531 parcels.
