Ecological footprint (EF) has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some...Ecological footprint (EF) has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some scholars in these fields have proposed alternative methods to calculate EF and have made some progress. This paper, therefore, begins with the introduction and development of EF in China. However, the established methods of EF calculation hold some limitations, such as indicator variance and result abnormality. In order to resolve those problems, the authors make a further modification considering the demand of EF as a comprehensive indicator: 1) More accurate analysis has been done to divide EF into several parts: imported EF, exported EF, and producible EF, which is the solution to the problem of abnormality in original EF results and can explain abnormal phenomena reasonably. 2) Considering the actual situa- tion of Shanghai, emended equivalence factor is brought forward and a matrix is formed with equivalence factors. The measure can reduce the deviation between the fact and the results. 3) The calculation compares local yield with global average yield to analyze the effects of yields. And based on local yields in different years, the results are more accurate. Finally, the calculation method is applied to calculating EF of Shanghai from 1980 to 2003, and the subsequent detailed analysis is presented. Available data and results suggest a statistically significant correlation coefficient between EF and GDP, population density and urbaniTation level. Through analyzing the process of calculating EF and its results, it can be seen that EF, as a macro-indicator, can not exactly indicate whether development within a region can meet the re- quests of sustainable development, which can be explained by the fact that the result of EF is impacted greatly by sub- jective factors including national policy,available technology, population, etc. Nevertheless, EF can demonstrate, at least to some degree, the regional status in terms of resources and energy consumption, as well as developmental potential. The calculation of EF, therefore, deserves further research to achieve more far-reaching significance in application.展开更多
Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and...Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and initial pH value on degradation of chlorothalonil,as well as the reaction mechanism were studied.The results reveal that chlorothalonil could be effectively degradated by ultrasonic irradiation.The reaction constant value kapp decreased from 0.014 1 to 0.010 2 min-1 with the initial concentration increasing from 50 to 400 μg/L during 180 min irradiation.Tertiary butyl alcohol had negative effect on chlorothalonil degradation,while lower concentration of humic acid promoted the sonolysis,and kapp declined with the further concentration increasing.The kapp varied little when the pH value ranged from 3.10 to 10.28.It may be concluded that mechanical and pyrolysis process played main roles on the degradation of chlorothalonil in ultrasonic irradiation rather than ·OH attack.The electrical energy per order(EEo) values for sonolysis degradation of CLT were also calculated to evaluate the cost of the process.展开更多
CO2 concentrations in different plant communities (larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and ann...CO2 concentrations in different plant communities (larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO2 concentration in different spaces. CO2 concentration in different communities in green lands had an obvious diurnal variation, chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO2 was lowest in the larch green land (344.03 ±23.03 μmol/mol) and highest in the grassland (360.13 ± 22.43 μmol/mol). The overall trend in CO2 concentration was autumn 〉 spring 〉 summer; temperature is the main factor controlling variation in CO2 concentrations during the growing season; the CO2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.展开更多
Nitrogen huff-n-puff(N_(2)HnP) appears to be an economical and high-efficiency enhanced oil recovery(EOR) technique for tight oil reservoirs.There is however a lack of understanding of the pore-level EOR performance o...Nitrogen huff-n-puff(N_(2)HnP) appears to be an economical and high-efficiency enhanced oil recovery(EOR) technique for tight oil reservoirs.There is however a lack of understanding of the pore-level EOR performance of N2HnP under tight reservoir conditions.In this work,a non-magnetic reactor was created and combined with a nuclear magnetic resonance(NMR) device for real-time monitoring of oil distribution in the HnP experiment.N_(2)HnP experiments were then performed in a tight sandstone core sample at a temperature of 353 K and an injection pressure≥ 24 MPa.The pore-level oil distribution under reservoir conditions was monitored and the EOR performance of N2HnP in specific pores was analyzed.The pore throat structures of the core sample and the phase behavior of the N_(2)-Oil system were analyzed to elucidate the EOR mechanism of N_(2)HnP.An oil recovery factor of 37.52% can be achieved after four cycles,which proves the EOR potential of N_(2)HnP for tight reservoirs.The highest recoveries after N_(2)HnP are obtained in the large pores,followed by the medium pores,the small pores,and finally the micro pores.Increases in soaking time and injection pressure resulted in slight and pronounced increases in oil recovery,respectively,both of which are mainly reflected in the first cycle.Specifically,increasing the soaking time only slightly improves the cumulative oil recovery in the small pores while increasing the injection pressure significantly improves the cumulative oil recovery in the small,medium,and large pores simultaneously.However,variations in both injection pressure and soaking time have a negligible effect on the cumulative oil recovery of the micro pores.展开更多
Studies are conducted by using activated carbon process aimed at bromate removal from the raw water.Screening of activated carbon for bromate removal was performed in different activated carbons.GAC Merck possesses th...Studies are conducted by using activated carbon process aimed at bromate removal from the raw water.Screening of activated carbon for bromate removal was performed in different activated carbons.GAC Merck possesses the highest iodine number and surface area,the highest number of basic groups and Vmeso,thereby contains the highest adsorption velocity and adsorption capacity.Impact factors of bromate removal on activated carbon were studied.Through static absorption experiments we studied the effect of adsorption time,pH,temperature,anions and organic matter on bromate removal.With the decrease of pH,removal of bromate enhanced,suggests that it may be possible to increase bromate reduction through pH control.The increase of temperature will be favorable to adsorption of bromate on activated carbon.Anions and organic matter can inhibit the adsorption of bromate on activated carbon through competing active sites.Bromate removal can be improved by controlling key water quality parameters.展开更多
The distribution characteristics of rare earth elements (REE) in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships bet...The distribution characteristics of rare earth elements (REE) in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships between ΣREE content andprovenance, hydrodynamics, grain size and mineral distribution in the Beibu Gulf showsthat terrestrial rocks control the ΣREE composition. Both weaker hydrodynamics andfiner grain size lead to a higher ΣREE content. Relative curves revealing therelationships between individual impact factors and ΣREE content were obtained fromthe combination of qualitative and quantitative analyses of the BP neural network,which trained the position of samples, gravel content, sand content, silt content, claycontent and clay mineral content. The results are consistent with those of thequantitative analysis. The self-learning algorithm is automatically determined andcalculated quantitatively. The impact of each factor on REEs and how each factorcontrols the ΣREE distribution is identified. Thus, environmental changes and thegeological evolution of the region can be inferred based on curve variation and the geological evolution of the region can be inferred based on curve variation and theactual situation. This method also provides useful theoretical guidance for the analysisof REE enrichment and dispersion.展开更多
Dietary sodium intake and its impact factors in 2 140 adults aged 18-69 years were analyzed. The mean daily sodium intake was 5 745.0 (5 427.6- 6 062.5) mg per day, which was higher in males than in females (P〈0.0...Dietary sodium intake and its impact factors in 2 140 adults aged 18-69 years were analyzed. The mean daily sodium intake was 5 745.0 (5 427.6- 6 062.5) mg per day, which was higher in males than in females (P〈0.01). After having been adjusted for gender, age and urban/city areas, the mean daily sodium intake was significantly higher in participants with a lower education level, drinkers and smokers than in those with a higher education level, nondrinkers and nonsmokers (P〈O.01). The dietary sodium intake in adults of Shandong Province is higher than the recommended standards.展开更多
Based on data of monthly pan evaporation,temperature,precipitation,sunshine hours,wind speed,relative humidity,etc. in Benxi County during 1958-2012 from Meteorological Bureau of Benxi County,annual,seasonal and month...Based on data of monthly pan evaporation,temperature,precipitation,sunshine hours,wind speed,relative humidity,etc. in Benxi County during 1958-2012 from Meteorological Bureau of Benxi County,annual,seasonal and monthly changes and impact factors of pan evaporation in Benxi County in recent 55 years were analyzed. The results showed that annual evaporation in Benxi County showed a decreasing trend from 1958 to 2012,with the linear tendency rate of-12. 18 mm/10 a. Except that evaporation in spring decreased obviously,but evaporation in other seasons increased slightly in recent 55 years. Moreover,evaporation changes correlated with changes of average temperature,daily range of temperature,precipitation,sunshine hours,average wind speed and relative humidity,but the correlations between evaporation and each meteorological element were different in various seasons.展开更多
Objective To analyze the factors that impact the environment quality of cleaning operating room and to discuss improvement measurement. Methods Environment bacteria testing results and prevalence of surgical incision ...Objective To analyze the factors that impact the environment quality of cleaning operating room and to discuss improvement measurement. Methods Environment bacteria testing results and prevalence of surgical incision infection in cleaning operating room were retro-展开更多
Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity.Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patter...Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity.Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns.Five southern islands in the Miaodao Archipelago,North China were studied herein.The spatial distribution of herbaceous plant diversity on these islands was analyzed,and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA.The results reveal 114 herbaceous plant species,belonging to 94 genera from 34 families in the50 plots sampled.The total species numbers on different islands were significantly positively correlated with island area,and the average a diversity was correlated with human activities,while the(3 diversity among islands was more affected by island area than mutual distances.Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude,slope,total nitrogen,total carbon,and canopy density,and lower moisture content,pH,total phosphorus,total potassium,and aspect.Among the environmental factors,pH,canopy density,total K,total P,moisture content,altitude,and slope had significant gross effects,but only canopy density exhibited a significant net effect.Terrain affected diversity by restricting plantation,plantation in turn influenced soil properties and the two together affected diversity.Therefore,plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.展开更多
This article developed a decomposition model of energy productivity on the basis of the economic growth model. Four factors were considered which may influence China’s energy productivity according to this model: tec...This article developed a decomposition model of energy productivity on the basis of the economic growth model. Four factors were considered which may influence China’s energy productivity according to this model: technology improvement, resource allocation structure, industrial structure and institute arrangement. Then, an econometric model was employed to test the four factors empirically on the basis of China’s statistical data from 1978 to 2004. Results indicated that capital deepening con- tributes the most (207%) to energy efficiency improvement, and impact from labor forces (13%) is the weakest one in resource factor; industrial structure (7%) and institute innovation (9.5%) positively improve the energy productivity.展开更多
Block-flexure toppling failure is frequently encountered in interbedded anti-inclined rock(IAR)slopes,and seriously threatens the construction of hydropower infrastructure.In this study,we first investigated the Lean ...Block-flexure toppling failure is frequently encountered in interbedded anti-inclined rock(IAR)slopes,and seriously threatens the construction of hydropower infrastructure.In this study,we first investigated the Lean Reservoir area’s geological setting and the Linda landslide’s characteristics.Then,uniform design and random design were used to design 110 training datasets and 31 testing datasets,respectively.Afterwards,the toppling response was obtained by using the discrete element code.Finally,support vector regression was used to obtain the influence weights of 21 impact factors.The results show that the influence weight of the slope angle and rock formation dip angle on the toppling deformation among tertiary impact factors is 25.96%and 17.28%,respectively,which are much greater than the other 19 impact factors within the research range.For the primary impact factors,the influence weight is sorted from large to small as slope geometry parameters,joints parameters,and rock mechanics parameters.Joints parameters,especially the geometric parameters,cannot be ignored when evaluating the stability of IAR slopes.Through numerical simulation,it was qualitatively determined that failure surfaces of slopes were controlled by cross joints and that the rocks in the slope toe play a role in preventing slope deformation.展开更多
A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solu...A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this method.The method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are analyzed.The results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the bridge.Notably,the influence of wheelto-bridge friction forces is of particular significance and cannot be overlooked.When the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking acceleration.Under favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by codes.It is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.展开更多
This work presents a novel approach to the dynamic response analysis of a Euler-Bernoulli beam resting on a Winkler soil model and subjected to an impact loading.The approach considers that damping has much less impor...This work presents a novel approach to the dynamic response analysis of a Euler-Bernoulli beam resting on a Winkler soil model and subjected to an impact loading.The approach considers that damping has much less importance in controlling the maximum response to impulsive loadings because the maximum response is reached in a very short time,before the damping forces can dissipate a significant portion of the energy input into the system.The development of two sine series solutions,relating to different types of impulsive loadings,one involving a single concentrated force and the other a distributed line load,are presented.This study revealed that when a simply supported Euler-Bernoulli beam,resting on a Winkler soil model,is subject to an impact load,the resulting vertical displacements,bending moments and shear forces produced along the span of the beam are considerably affected.In particular,the quantification of this effect is best observed,relative to the corresponding static solution,via an amplification factor.The computed impact amplification factors,for the sub-grade moduli used in this study,were in magnitude greater than 2,thus confirming the multiple-degree-of-freedom nature of the problem.展开更多
Nitrocellulose membrane(NCM)can produce hydroxyl radicals under illumination,which promotes the oxidative degradation of organic pollutants.In this paper,NCM was used to oxidize bisphenol A(BPA)under simulated sunligh...Nitrocellulose membrane(NCM)can produce hydroxyl radicals under illumination,which promotes the oxidative degradation of organic pollutants.In this paper,NCM was used to oxidize bisphenol A(BPA)under simulated sunlight.The effects of p H,temperature,light intensity,anion and cation on the degradation of BPA were analyzed.The photodegradation process of BPA was discussed.The optimal photolysis rate was 0.031 min^(-)1 when the temperature was 30°C,the light intensity was 2.67×10^4 Lux,and the p H value was 9.0.The alkaline environment,temperature and light intensity can promote the photodegradation of BPA.Except for nitrate ions,anions and cations can inhibit the photodegradation of BPA.Compared with cations,anions have a greater inhibitory effect on BPA degradation.The degradation products of BPA by NCM were analyzed by gas chromatographic/mass.This study may provide useful information for the BPA degradation by NCM in complex water samples.展开更多
In the present study,we analyzed the chemical properties and factors impacting the sea fog water during two sea fog events over the northwestern South China Sea in March 2017,and compared our results with those of oth...In the present study,we analyzed the chemical properties and factors impacting the sea fog water during two sea fog events over the northwestern South China Sea in March 2017,and compared our results with those of other regions.The sea fog water during these two events were highly acidic and their average pH was below 3,which was related to the high initial acidifying potential and large amounts of NOand SOnot involved in the neutralization reaction.The dominant cations in the sea fog water were Naand NH.The primary anions in the sea fog water over the South China Sea were Cland NO,while that over the North Pacific Ocean was mainly SO,and ratios of the three fog water ions near the Donghai Island were similar.Ions in the sea fog water during the two events were mainly derived from marine aerosols,while the difference was that the first low-level sea fog airflow trajectory passed over Hainan Island.Therefore,the proportion of K+in the first sea fog was much higher than that in sea water and the second.Sulfate was the key to fog water nucleation,which made ion concentration in the sea fog water during the second event higher than that during the first.A decrease in average diameter during the first sea fog formation led to an ion concentration increase,while the average diameter of sea fog water during the second event was lower than that during the first,which corresponded with a moderate ion concentration increase.展开更多
In this study, we investigate the impact factors on air pollution in terms of CO2, SO2 and NOx emissions simultaneously in China and compare changes in air pollution across provinces from 1998 to 2011 using a Multiple...In this study, we investigate the impact factors on air pollution in terms of CO2, SO2 and NOx emissions simultaneously in China and compare changes in air pollution across provinces from 1998 to 2011 using a Multiple Indicators and Multiple Causes Model (MIMIC) within a Structural Equation Model (SEM) framework. Our findings reveal that GDP per capita and total population have the largest impacts on air pollution, followed by energy intensity, foreign direct investment, population density, and industrialization. The results also reveal that the inverted U-shaped Environmental Kuznets Curve (EKC) hypothesis exists in China. Our findings also demonstrate that Shandong, Jiangxi and Liaoning are the top three provinces with the most deteriorated air quality while Xinjiang, Fujian and Ningxia are with the best. These results not only contribute to advancing the existing literature, but also merit particular attention from policy-makers in China.展开更多
Elemental mercury(Hg^0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg^2 +)standard solution was injected into the simulated scrubber at a desired rat...Elemental mercury(Hg^0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg^2 +)standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 +in the flue gas across wet flue gas desulfurization(WFGD)systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2+to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 +,Pb ^2+,Ni ^2+, AsO2^-and Cu ^+were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 +to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were:Pb^2 +〉Cu ^+〉Fe^ 2+〉 AsO2^-〉Ni ^2+.展开更多
Based on a winter field experiment between 2016 and 2017,four treatments(bare land(BL),natural snowfall coverage(NS),5-cm-deep straw+natural snowfall coverage(SC5),and 10-cm-deep straw+natural snowfall coverage(SC10))...Based on a winter field experiment between 2016 and 2017,four treatments(bare land(BL),natural snowfall coverage(NS),5-cm-deep straw+natural snowfall coverage(SC5),and 10-cm-deep straw+natural snowfall coverage(SC10))were established to determine the effects of the different treatments on soil temperature at the soil surface and at depths of 10 cm,20 cm,and 30 cm.The environmental factors of ambient temperature,ambient humidity,water vapor pressure,10-min wind speed,total radiation,net radiation,and long wave radiation were obtained from the weather station in the study area.Through correlation,multiple regression,and stepwise regression analysis,models for dynamic simulation of the tillage-layer soil temperature were constructed for analyzing the relation between tillage-layer soil temperature and environmental factors.The results showed that the environmental factors were all significantly correlated with tillage-layer temperature at the 0.01 level;when the impacts of other environmental factors were excluded,the correlations decreased significantly.The dynamic simulation models for tillage-layer soil temperature under different coverage conditions were different,and the larger the coverage amount,the fewer the environmental factors that could affect the tillage-layer temperature.The coefficients of determination of the prediction results of the dynamic models for the tillage-layer soil temperature under the four treatments(BL,NS,SC5,and SC10)were 0.8385,0.7110,0.7283,and 0.6216,respectively.The prediction had a high accuracy and can accurately depict the dynamic changes of the tillage-layer soil temperature.The results provided a theoretical basis for the efficient utilization of farmland soil water and heat resources.展开更多
基金Under the auspices of the Major State Basic Research Development Program of China (973 Program) (No 2005CB724201)
文摘Ecological footprint (EF) has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some scholars in these fields have proposed alternative methods to calculate EF and have made some progress. This paper, therefore, begins with the introduction and development of EF in China. However, the established methods of EF calculation hold some limitations, such as indicator variance and result abnormality. In order to resolve those problems, the authors make a further modification considering the demand of EF as a comprehensive indicator: 1) More accurate analysis has been done to divide EF into several parts: imported EF, exported EF, and producible EF, which is the solution to the problem of abnormality in original EF results and can explain abnormal phenomena reasonably. 2) Considering the actual situa- tion of Shanghai, emended equivalence factor is brought forward and a matrix is formed with equivalence factors. The measure can reduce the deviation between the fact and the results. 3) The calculation compares local yield with global average yield to analyze the effects of yields. And based on local yields in different years, the results are more accurate. Finally, the calculation method is applied to calculating EF of Shanghai from 1980 to 2003, and the subsequent detailed analysis is presented. Available data and results suggest a statistically significant correlation coefficient between EF and GDP, population density and urbaniTation level. Through analyzing the process of calculating EF and its results, it can be seen that EF, as a macro-indicator, can not exactly indicate whether development within a region can meet the re- quests of sustainable development, which can be explained by the fact that the result of EF is impacted greatly by sub- jective factors including national policy,available technology, population, etc. Nevertheless, EF can demonstrate, at least to some degree, the regional status in terms of resources and energy consumption, as well as developmental potential. The calculation of EF, therefore, deserves further research to achieve more far-reaching significance in application.
基金Project(2008ZX07421-002) supported by the National Major Project of Science & Technology Ministry of ChinaProject(2008AA06A412) supported by the National High Technology Research and Development Program of ChinaProject(20009-K7-4) supported by the Research and Development of Ministry of Housing and Urban-Rural Development of China
文摘Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and initial pH value on degradation of chlorothalonil,as well as the reaction mechanism were studied.The results reveal that chlorothalonil could be effectively degradated by ultrasonic irradiation.The reaction constant value kapp decreased from 0.014 1 to 0.010 2 min-1 with the initial concentration increasing from 50 to 400 μg/L during 180 min irradiation.Tertiary butyl alcohol had negative effect on chlorothalonil degradation,while lower concentration of humic acid promoted the sonolysis,and kapp declined with the further concentration increasing.The kapp varied little when the pH value ranged from 3.10 to 10.28.It may be concluded that mechanical and pyrolysis process played main roles on the degradation of chlorothalonil in ultrasonic irradiation rather than ·OH attack.The electrical energy per order(EEo) values for sonolysis degradation of CLT were also calculated to evaluate the cost of the process.
文摘CO2 concentrations in different plant communities (larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO2 concentration in different spaces. CO2 concentration in different communities in green lands had an obvious diurnal variation, chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO2 was lowest in the larch green land (344.03 ±23.03 μmol/mol) and highest in the grassland (360.13 ± 22.43 μmol/mol). The overall trend in CO2 concentration was autumn 〉 spring 〉 summer; temperature is the main factor controlling variation in CO2 concentrations during the growing season; the CO2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.
基金financial support from the National Natural Science Foundation of China(52074319)the Strategic Cooperation Technology Project of CNPC(ZLZX2020-01-08)the Science Foundation of China University of Petroleum-Beijing(2462021QNXZ008)
文摘Nitrogen huff-n-puff(N_(2)HnP) appears to be an economical and high-efficiency enhanced oil recovery(EOR) technique for tight oil reservoirs.There is however a lack of understanding of the pore-level EOR performance of N2HnP under tight reservoir conditions.In this work,a non-magnetic reactor was created and combined with a nuclear magnetic resonance(NMR) device for real-time monitoring of oil distribution in the HnP experiment.N_(2)HnP experiments were then performed in a tight sandstone core sample at a temperature of 353 K and an injection pressure≥ 24 MPa.The pore-level oil distribution under reservoir conditions was monitored and the EOR performance of N2HnP in specific pores was analyzed.The pore throat structures of the core sample and the phase behavior of the N_(2)-Oil system were analyzed to elucidate the EOR mechanism of N_(2)HnP.An oil recovery factor of 37.52% can be achieved after four cycles,which proves the EOR potential of N_(2)HnP for tight reservoirs.The highest recoveries after N_(2)HnP are obtained in the large pores,followed by the medium pores,the small pores,and finally the micro pores.Increases in soaking time and injection pressure resulted in slight and pronounced increases in oil recovery,respectively,both of which are mainly reflected in the first cycle.Specifically,increasing the soaking time only slightly improves the cumulative oil recovery in the small pores while increasing the injection pressure significantly improves the cumulative oil recovery in the small,medium,and large pores simultaneously.However,variations in both injection pressure and soaking time have a negligible effect on the cumulative oil recovery of the micro pores.
基金Sponsored by High-Tech Research and Development Program (Grant No.2006AA06Z311)National Creative Research Groups (Grant No.50821002)+1 种基金National Science and Technology Support Funding (Grant No.2006BAJ08B0)Project Supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology(HITQNJS.2008.044)
文摘Studies are conducted by using activated carbon process aimed at bromate removal from the raw water.Screening of activated carbon for bromate removal was performed in different activated carbons.GAC Merck possesses the highest iodine number and surface area,the highest number of basic groups and Vmeso,thereby contains the highest adsorption velocity and adsorption capacity.Impact factors of bromate removal on activated carbon were studied.Through static absorption experiments we studied the effect of adsorption time,pH,temperature,anions and organic matter on bromate removal.With the decrease of pH,removal of bromate enhanced,suggests that it may be possible to increase bromate reduction through pH control.The increase of temperature will be favorable to adsorption of bromate on activated carbon.Anions and organic matter can inhibit the adsorption of bromate on activated carbon through competing active sites.Bromate removal can be improved by controlling key water quality parameters.
文摘The distribution characteristics of rare earth elements (REE) in bottomsediments are influenced by many factors. Hence, conducting a quantitative analysis isdifficult. A qualitative analysis of the relationships between ΣREE content andprovenance, hydrodynamics, grain size and mineral distribution in the Beibu Gulf showsthat terrestrial rocks control the ΣREE composition. Both weaker hydrodynamics andfiner grain size lead to a higher ΣREE content. Relative curves revealing therelationships between individual impact factors and ΣREE content were obtained fromthe combination of qualitative and quantitative analyses of the BP neural network,which trained the position of samples, gravel content, sand content, silt content, claycontent and clay mineral content. The results are consistent with those of thequantitative analysis. The self-learning algorithm is automatically determined andcalculated quantitatively. The impact of each factor on REEs and how each factorcontrols the ΣREE distribution is identified. Thus, environmental changes and thegeological evolution of the region can be inferred based on curve variation and the geological evolution of the region can be inferred based on curve variation and theactual situation. This method also provides useful theoretical guidance for the analysisof REE enrichment and dispersion.
基金supported by the Science and Technology Development Plan Project of Shandong Province(2012GSF11828)
文摘Dietary sodium intake and its impact factors in 2 140 adults aged 18-69 years were analyzed. The mean daily sodium intake was 5 745.0 (5 427.6- 6 062.5) mg per day, which was higher in males than in females (P〈0.01). After having been adjusted for gender, age and urban/city areas, the mean daily sodium intake was significantly higher in participants with a lower education level, drinkers and smokers than in those with a higher education level, nondrinkers and nonsmokers (P〈O.01). The dietary sodium intake in adults of Shandong Province is higher than the recommended standards.
文摘Based on data of monthly pan evaporation,temperature,precipitation,sunshine hours,wind speed,relative humidity,etc. in Benxi County during 1958-2012 from Meteorological Bureau of Benxi County,annual,seasonal and monthly changes and impact factors of pan evaporation in Benxi County in recent 55 years were analyzed. The results showed that annual evaporation in Benxi County showed a decreasing trend from 1958 to 2012,with the linear tendency rate of-12. 18 mm/10 a. Except that evaporation in spring decreased obviously,but evaporation in other seasons increased slightly in recent 55 years. Moreover,evaporation changes correlated with changes of average temperature,daily range of temperature,precipitation,sunshine hours,average wind speed and relative humidity,but the correlations between evaporation and each meteorological element were different in various seasons.
文摘Objective To analyze the factors that impact the environment quality of cleaning operating room and to discuss improvement measurement. Methods Environment bacteria testing results and prevalence of surgical incision infection in cleaning operating room were retro-
基金Supported by the National Special Fund for Basic Science and Technology of China(No.2012FY112500)the Public Science and Technology Research Funds Projects of Ocean in China(Nos.201305009,201505012)the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes(No.FIO2015G13)
文摘Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity.Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns.Five southern islands in the Miaodao Archipelago,North China were studied herein.The spatial distribution of herbaceous plant diversity on these islands was analyzed,and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA.The results reveal 114 herbaceous plant species,belonging to 94 genera from 34 families in the50 plots sampled.The total species numbers on different islands were significantly positively correlated with island area,and the average a diversity was correlated with human activities,while the(3 diversity among islands was more affected by island area than mutual distances.Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude,slope,total nitrogen,total carbon,and canopy density,and lower moisture content,pH,total phosphorus,total potassium,and aspect.Among the environmental factors,pH,canopy density,total K,total P,moisture content,altitude,and slope had significant gross effects,but only canopy density exhibited a significant net effect.Terrain affected diversity by restricting plantation,plantation in turn influenced soil properties and the two together affected diversity.Therefore,plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.
文摘This article developed a decomposition model of energy productivity on the basis of the economic growth model. Four factors were considered which may influence China’s energy productivity according to this model: technology improvement, resource allocation structure, industrial structure and institute arrangement. Then, an econometric model was employed to test the four factors empirically on the basis of China’s statistical data from 1978 to 2004. Results indicated that capital deepening con- tributes the most (207%) to energy efficiency improvement, and impact from labor forces (13%) is the weakest one in resource factor; industrial structure (7%) and institute innovation (9.5%) positively improve the energy productivity.
基金supported by the National Key Scientific Instrument and Equipment Development Projects of China(No.41827808)the Major Program of the National Natural Science Foundation of China(No.42090055).
文摘Block-flexure toppling failure is frequently encountered in interbedded anti-inclined rock(IAR)slopes,and seriously threatens the construction of hydropower infrastructure.In this study,we first investigated the Lean Reservoir area’s geological setting and the Linda landslide’s characteristics.Then,uniform design and random design were used to design 110 training datasets and 31 testing datasets,respectively.Afterwards,the toppling response was obtained by using the discrete element code.Finally,support vector regression was used to obtain the influence weights of 21 impact factors.The results show that the influence weight of the slope angle and rock formation dip angle on the toppling deformation among tertiary impact factors is 25.96%and 17.28%,respectively,which are much greater than the other 19 impact factors within the research range.For the primary impact factors,the influence weight is sorted from large to small as slope geometry parameters,joints parameters,and rock mechanics parameters.Joints parameters,especially the geometric parameters,cannot be ignored when evaluating the stability of IAR slopes.Through numerical simulation,it was qualitatively determined that failure surfaces of slopes were controlled by cross joints and that the rocks in the slope toe play a role in preventing slope deformation.
基金supported by the Henan Provincial Science and Technology Research Project under Grant(152102310295).
文摘A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this method.The method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are analyzed.The results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the bridge.Notably,the influence of wheelto-bridge friction forces is of particular significance and cannot be overlooked.When the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking acceleration.Under favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by codes.It is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.
基金l’UniversitéLaval for the financial support of his sabbatical year at Dipartimento di Bioscienze e Territorio,Universitàdegli Studi del Molise in Campobasso,Italy。
文摘This work presents a novel approach to the dynamic response analysis of a Euler-Bernoulli beam resting on a Winkler soil model and subjected to an impact loading.The approach considers that damping has much less importance in controlling the maximum response to impulsive loadings because the maximum response is reached in a very short time,before the damping forces can dissipate a significant portion of the energy input into the system.The development of two sine series solutions,relating to different types of impulsive loadings,one involving a single concentrated force and the other a distributed line load,are presented.This study revealed that when a simply supported Euler-Bernoulli beam,resting on a Winkler soil model,is subject to an impact load,the resulting vertical displacements,bending moments and shear forces produced along the span of the beam are considerably affected.In particular,the quantification of this effect is best observed,relative to the corresponding static solution,via an amplification factor.The computed impact amplification factors,for the sub-grade moduli used in this study,were in magnitude greater than 2,thus confirming the multiple-degree-of-freedom nature of the problem.
基金the Plan for Scientific Innovation Talent of Henan Province(No.19420051001)the major project for Henan Province Joint Funds of the National Natural Science Foundation of China(No.U1704241)the National Natural Science Foundation of China(No.41702174)。
文摘Nitrocellulose membrane(NCM)can produce hydroxyl radicals under illumination,which promotes the oxidative degradation of organic pollutants.In this paper,NCM was used to oxidize bisphenol A(BPA)under simulated sunlight.The effects of p H,temperature,light intensity,anion and cation on the degradation of BPA were analyzed.The photodegradation process of BPA was discussed.The optimal photolysis rate was 0.031 min^(-)1 when the temperature was 30°C,the light intensity was 2.67×10^4 Lux,and the p H value was 9.0.The alkaline environment,temperature and light intensity can promote the photodegradation of BPA.Except for nitrate ions,anions and cations can inhibit the photodegradation of BPA.Compared with cations,anions have a greater inhibitory effect on BPA degradation.The degradation products of BPA by NCM were analyzed by gas chromatographic/mass.This study may provide useful information for the BPA degradation by NCM in complex water samples.
基金National Key R&D Program of China(2018YFA0605604)Guangxi Key Research and Development Program(AB20159013)+2 种基金Strategic Priority Research Program of Chinese Academy of Sciences(XDA20060503)Key Area R&D Program of Guangdong Province(2020B0101130021)National Natural Science Foundation of China(41675136)。
文摘In the present study,we analyzed the chemical properties and factors impacting the sea fog water during two sea fog events over the northwestern South China Sea in March 2017,and compared our results with those of other regions.The sea fog water during these two events were highly acidic and their average pH was below 3,which was related to the high initial acidifying potential and large amounts of NOand SOnot involved in the neutralization reaction.The dominant cations in the sea fog water were Naand NH.The primary anions in the sea fog water over the South China Sea were Cland NO,while that over the North Pacific Ocean was mainly SO,and ratios of the three fog water ions near the Donghai Island were similar.Ions in the sea fog water during the two events were mainly derived from marine aerosols,while the difference was that the first low-level sea fog airflow trajectory passed over Hainan Island.Therefore,the proportion of K+in the first sea fog was much higher than that in sea water and the second.Sulfate was the key to fog water nucleation,which made ion concentration in the sea fog water during the second event higher than that during the first.A decrease in average diameter during the first sea fog formation led to an ion concentration increase,while the average diameter of sea fog water during the second event was lower than that during the first,which corresponded with a moderate ion concentration increase.
文摘In this study, we investigate the impact factors on air pollution in terms of CO2, SO2 and NOx emissions simultaneously in China and compare changes in air pollution across provinces from 1998 to 2011 using a Multiple Indicators and Multiple Causes Model (MIMIC) within a Structural Equation Model (SEM) framework. Our findings reveal that GDP per capita and total population have the largest impacts on air pollution, followed by energy intensity, foreign direct investment, population density, and industrialization. The results also reveal that the inverted U-shaped Environmental Kuznets Curve (EKC) hypothesis exists in China. Our findings also demonstrate that Shandong, Jiangxi and Liaoning are the top three provinces with the most deteriorated air quality while Xinjiang, Fujian and Ningxia are with the best. These results not only contribute to advancing the existing literature, but also merit particular attention from policy-makers in China.
基金Supported by the US Agency for International Development(USAID)cooperation agreement(486-A-00-06-000140-00)
文摘Elemental mercury(Hg^0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg^2 +)standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 +in the flue gas across wet flue gas desulfurization(WFGD)systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2+to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 +,Pb ^2+,Ni ^2+, AsO2^-and Cu ^+were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 +to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were:Pb^2 +〉Cu ^+〉Fe^ 2+〉 AsO2^-〉Ni ^2+.
基金supported by the National Natural Science Foundation of China(51679039)the Outstanding Youth Fund of Heilongjiang Province(JC201402).
文摘Based on a winter field experiment between 2016 and 2017,four treatments(bare land(BL),natural snowfall coverage(NS),5-cm-deep straw+natural snowfall coverage(SC5),and 10-cm-deep straw+natural snowfall coverage(SC10))were established to determine the effects of the different treatments on soil temperature at the soil surface and at depths of 10 cm,20 cm,and 30 cm.The environmental factors of ambient temperature,ambient humidity,water vapor pressure,10-min wind speed,total radiation,net radiation,and long wave radiation were obtained from the weather station in the study area.Through correlation,multiple regression,and stepwise regression analysis,models for dynamic simulation of the tillage-layer soil temperature were constructed for analyzing the relation between tillage-layer soil temperature and environmental factors.The results showed that the environmental factors were all significantly correlated with tillage-layer temperature at the 0.01 level;when the impacts of other environmental factors were excluded,the correlations decreased significantly.The dynamic simulation models for tillage-layer soil temperature under different coverage conditions were different,and the larger the coverage amount,the fewer the environmental factors that could affect the tillage-layer temperature.The coefficients of determination of the prediction results of the dynamic models for the tillage-layer soil temperature under the four treatments(BL,NS,SC5,and SC10)were 0.8385,0.7110,0.7283,and 0.6216,respectively.The prediction had a high accuracy and can accurately depict the dynamic changes of the tillage-layer soil temperature.The results provided a theoretical basis for the efficient utilization of farmland soil water and heat resources.