Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated t...Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.展开更多
Atmospheric wet deposition plays an important role in the supply of nutrients and toxic substances to terrestrial and aquatic environments. Although long-term(e.g. annual, multi-year) wet deposition is recorded well...Atmospheric wet deposition plays an important role in the supply of nutrients and toxic substances to terrestrial and aquatic environments. Although long-term(e.g. annual, multi-year) wet deposition is recorded well, pronounced and short-term changes in precipitation chemistry are less well investigated. In the present study, the precipitation chemistry and scavenging ratio of air pollutants were observed during an extreme torrential rain event(325.6 mm at the observation site) that occurred over 19–21 July 2016 in the North China Plain(NCP). The scavenging ratio of particles showed a similar spatial distribution to that of the precipitation amount in the NCP, indicating the efficient removal of particulate matter due to the large amount and precipitation intensity of the storm. In addition, the scavenging ratio of water soluble ions was larger than that of organics and gaseous pollutants such as SO_2 and NO_2, likely due to their differences in water solubility.Consequently, raindrops incorporated more aerosol sulfate than gaseous compounds. Due to the heavy precipitation amount, almost all species in rainwater during this storm showed their lowest concentration but the highest flux compared with other rain events, indicating an important role played by this storm in terms of the substances received by the terrestrial and marine ecosystems of the region. However, the contribution of this storm to the annual chemical flux was lower than that of precipitation amount, indicating that the atmospheric compounds were scavenged below-cloud first and were then diluted by the cloud/rainwater. Future studies are needed in the context of the occurrence of extreme rainfall events in the NCP from the perspective of climate variability.展开更多
The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conve...The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conventional bioretention column(Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer(Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone(Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH+4—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO-3—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3—N.展开更多
Climatic factor's effect was studied on the radial growth of teak (Tectona grandis L.F.) by using the stem analysis of 36 trees distributed in 6 plantations in Parakou and Tchaourou districts in northern Benin. The...Climatic factor's effect was studied on the radial growth of teak (Tectona grandis L.F.) by using the stem analysis of 36 trees distributed in 6 plantations in Parakou and Tchaourou districts in northern Benin. The results showed that the plantations of Parakou were in general more productive than those of Tchaourou. The annual average growth was estimated in the first five years at 0.86 cm/year for Parakou and 0.76 cm/year at Tchaourou. The analysis of the radial growth showed that a significant percentage of the variance was allotted to the growth model. It follows that a big part of the ring width was predetermined before the intervention of the other factors, in particular the climatic conditions. The percentage of the variance related to the climatic conditions was thus more reduced for the plantations of Tchaourou than those of Parakou. The radial growth was influenced by the conditions of humidity (evapotranspiration, humidity and rain) of February to May on the one hand and those from August to October on the other hand.展开更多
Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as th...Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as thymol, formic and oxalic acid in different formulations and presentations. This kind of organic products has shown a variable acaricidal capacity, since different factors affect their efficacy such as ambient temperature and humidity, product presentation and location inside the hive, etc.. In Chile, beekeeping takes place in four different climatic zones, in which ambient temperature and humidity as well as the duration of the apicultural season are different. Therefore, the aim of this study was to determine how ambient temperature and humidity influence the efficacy of the organic treatments used in the beekeeping season. Different apiaries were installed in those climatic zones in three seasons between the years 2009 and 2012. All beehives received the same management in each apiary and it was evaluated the same organic treatments in different formulations and presentations. All the beehives were positive to Varroa, which was obtained using samples of adult bees and the soapy water test before and after each treatment. A thermo-hygrometer was installed in each apiary in order to monitor the ambient temperature (T°) and humidity (H°) conditions, which were registered daily for a period of 30 days since the beginning. It was obtained that the treatments' efficacy increases as the minimum T° and average T° rose, whereas on the contrary, the efficacy decreases when maximum H° was higher.展开更多
A two-stage ligand selection method composed of a primary selection and a critical selection,for complex-leaching valuable metals was presented.At the primary selection stage,three conditions were discussed under a su...A two-stage ligand selection method composed of a primary selection and a critical selection,for complex-leaching valuable metals was presented.At the primary selection stage,three conditions were discussed under a supposed ideal state by mathematical derivation.Generally,ligands selected under condition Ⅰwere easier for complex-leaching valuable metals than that under conditionⅡ,however,under conditionⅢ,ligands selected were hard to complex-leaching the valuable metals.Ligands that were out of these three conditions could be disposed directly.In critical selection,ligands selected in primary selection can be finalized.Case applications were provided for verifying the method.The application indicated that iminodiacetate(Ida2-)can be used as a complex agent for complex-leaching smithsonite(ZnCO3);the leaching condition should be controlled with pH 8-11;the relative error of the minimum consumption of Ida2-between the predicted and the calculated results is 5.3%.The results indicate that the theoretical derivations in the ideal state are reliable,and the method for ligand selection is practical and operable.展开更多
Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have r...Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have received a large amount of exogenous nitrogen (N) input from the adjacent agricultural land because of fertilization. In the present study, the effects of nitrogen additions on seed germination and seedling biomass of Calamagrostis angustifolia in freshwater marsh were tested in a greenhouse study. Seed bank soil was exposed to different N additions (0, 5, 10, 20 and 40 g/m^2) under non-flooded water regime. Results revealed that, low level of N additions (less than 10 g/m^2) did not significantly affect the species richness and seedling density, while the seedling biomass at 5 g/m^2 of N addition was higher than other nutrient conditions. But species richness, seedling emergence and biomass decreased significantly at high level of N additions (20-40 g/m^2). The responses were species-specific. High level of N additions had negative impacts on seed germination, seedling growth and biomass of dominant species Eleocharis ovata, Calamagrostis angustifolia, duncus effusus in the seed bank. To protect and restore the wetland vegetation community in the Sanjiang plain, fertilization, irrigation and land management strategies will need to be implemented to reduce the nutrient input from the agricultural land to the wetlands.展开更多
The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and ni...The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design(OAD) has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows: the temperature range of 70-90 ℃ for reaction temperature(T), 30-90 min for reaction time(t), 2-4 g/L for zinc powder mass concentration(M), one to five series for zinc dust particle size distributions(S1-S5), and 0.1-0.5 g/L(C) for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4(85 ℃), t4=75 min, M4=3.5 g/L, S4(Serie 4), and C2=0.2 g/L.展开更多
Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of...Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.展开更多
This study was conducted to establish a predictable method for a heat load of an underground structure with sufficient accuracy. As the first step, our previous paper reported the measurement results of field experime...This study was conducted to establish a predictable method for a heat load of an underground structure with sufficient accuracy. As the first step, our previous paper reported the measurement results of field experiments on an underground experimental basement under internal heat generation conditions. Also, it presented the results of numerical analyses on the heat and moisture behavior and the influence of internal heat generation of the experimental basement and ground. However, it is practically impossible to utilize the model of simultaneous heat and moisture transfer at the design phase because the prediction by the model of simultaneous heat and moisture transfer requires a long calculation time. In this paper, the authors present the simple load calculation technique, using a linearized approximation indicial response of the inner surface heat flux in a basement to outdoor air temperature change. In addition, the approximation indicial responses for each part of the single-walled concrete drawn using this technique are arranged. The heat load calculation example of application to the basement of the optional size by this technique is shown.展开更多
Due to climate change, the regional agro-climatic conditions in Southwest China have undergone changes. The heat sources for the growth of crops have been improved. The number of days with temperatures steadily above ...Due to climate change, the regional agro-climatic conditions in Southwest China have undergone changes. The heat sources for the growth of crops have been improved. The number of days with temperatures steadily above 0℃ and 10℃ (two criteria) have increased during 1960-2010. The area suitable for multiple cropping has increased; the growth period has shortened; the climatic potential productivity has declined; the pest damage has worsened. During 1986-2010, the desired cooling degree days in Southwest China has increased at 38.9℃ d per decade. Forest fires and pests have increased. The area of meadow and wetlands has decreased. Heterogeneous invasion has intensified; endangered animal and plant species have increased. The tourism landscape has been damaged.' The risk of human health has increased. In the 21st century, with the increase of temperature and precipitation, the number of days with temperature steadily above 10℃ and the accumulated temperature will continue to increase, most notably in the Qinghai-Tibetan Plateau. The area of intercropping will expand; multiple cropping will move to higher altitudes. The impacts of agro- meteorological disasters, pests and diseases will intensify. The summer cooling energy consumption continues to increase; energy supply will show larger variability; the gap between energy supply and demand will be widened. The phenology will keep on changing, and the habitat will be worsening. Biological population will move northward and to higher altitudes. Some species are at risk of extinction. Negative effects on health will increase.展开更多
YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means o...YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM).Superconducting properties of the YBCO films were measured by electromagnetic induction method.XRD results showed that c-axis-oriented grains existed in the YBCO films.Morphologies of the YBCO films showed that all the films had a smooth and crack-free surface.YBCO films prepared at 7.3% humidity condition showed Jc value of 4.6 MA cm-2 at 77 K in self-field.展开更多
This paper revealed the climatic change characteristics of fog and haze of different levels over North China and Huang-Huai area(NCHH).It was found that the haze-prone period has changed from winter into a whole year,...This paper revealed the climatic change characteristics of fog and haze of different levels over North China and Huang-Huai area(NCHH).It was found that the haze-prone period has changed from winter into a whole year,and the haze days(HD)in winter have increased significantly.The foggy days(FD)are half of HD.There are little difference on the number of days and trends of fog at various levels.The HD and FD show no obvious positive correlation until the 1980s.Fog has larger spatial scale,showing more in the south than in the north.Haze occurs mainly around large cities with a discrete distribution.In the background of weakened East Asian Winter Monsoon(EAWM)and sufficient particulate matter,the negative correlation between haze and wind speed is weakened,but the positive correlation between haze and moisture conditions(precipitation and humidity)is significantly strengthened.In recent years,small wind and variability appear frequently.Meanwhile,as the stable source and strong moisture absorption of the aerosol particles,the moisture condition becomes one key control factor in the haze,especially wet haze with less visibility.In contrast,the FD presents a stable positive correlation with precipitation and relative humidity,but has no obvious negative correlation with wind speed.展开更多
The long-term safe operation of high-power equipment and integrated electronic devices requires efficient thermal management,which in turn increases the energy consumption further.Hence,the sustainable development of ...The long-term safe operation of high-power equipment and integrated electronic devices requires efficient thermal management,which in turn increases the energy consumption further.Hence,the sustainable development of our society needs advanced thermal management with low,even zero,energy consumption.Harvesting water from the atmosphere,followed by moisture desorption to dissipate heat,is an efficient and feasible approach for zero-energy-consumption thermal management.However,current methods are limited by the low absorbance of water,low water vapor transmission rate(WVTR)and low stability,thus resulting in low thermal management capability.In this study,we report an innovative electrospinning method to process hierarchically porous metal–organic framework(MOF)composite fabrics with high-efficiency and zero-energy-consumption thermal management.The composite fabrics are highly loaded with MOF(75 wt%)and their WVTR value can be up to 3138 g m^(-2) d^(-1).The composite fabrics also exhibit stable microstructure and performance.Under a conventional environment(30℃,60%relative humidity),the composite fabrics adsorb water vapor for regeneration within 1.5 h to a saturated value Wsat of 0.614 g g^(-1),and a corresponding equivalent enthalpy of 1705.6 J g^(-1).In the thermal management tests,the composite fabrics show a strong cooling capability and significantly improve the performance of thermoelectric devices,portable storage devices and wireless chargers.These results suggest that hierarchically porous MOF composite fabrics are highly promising for thermal management of intermittent-operation electronic devices.展开更多
Water stability of soil is crucial to the durability of earthen monuments,especially those located in the humid weather condition.This paper discusses the selection reason of materials(tung oil and quicklime) for eart...Water stability of soil is crucial to the durability of earthen monuments,especially those located in the humid weather condition.This paper discusses the selection reason of materials(tung oil and quicklime) for earthen monument treatment,and then validates the applicability of these materials with tests of soil-water characteristic curve(SWCC),aggregate stability test(AST) and scanning electron microscope(SEM).The soil tested was sampled from Da Bao'en temple in Nanjing,Jiangsu province,China.The test results indicate that the carbonation reaction of quicklime offers a favorable environment for the formation of tung oil film.Meanwhile,the regulatory function of tung oil restricts the crystallinity of calcium carbonate(CaCO3) and forms fine crystals.Soil treated with both of tung oil and quicklime has good water repellency and aggregate stability without obvious changing in aesthetic appearance.Hydrophobicity and carbonation treatment can be applied prospectively in the conservation of earthen monument located in humid weather condition.展开更多
基金Major State Basic Research Development Program of China No.G1999043400+1 种基金 National Natural Science Foundation of China No.40375028
文摘Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.
基金supported by the National Natural Science Foundation of China[grant number 41405144]the National Key Research and Development Program of China[grant number2017YFC0210100],[grant number 2016YFD0800302],[grant number 2016YFC0201802]the Science and Technology Service Network Initiative of the Chinese Academy of Sciences[STS Plan,grant number KFJ-SW-STS-168]
文摘Atmospheric wet deposition plays an important role in the supply of nutrients and toxic substances to terrestrial and aquatic environments. Although long-term(e.g. annual, multi-year) wet deposition is recorded well, pronounced and short-term changes in precipitation chemistry are less well investigated. In the present study, the precipitation chemistry and scavenging ratio of air pollutants were observed during an extreme torrential rain event(325.6 mm at the observation site) that occurred over 19–21 July 2016 in the North China Plain(NCP). The scavenging ratio of particles showed a similar spatial distribution to that of the precipitation amount in the NCP, indicating the efficient removal of particulate matter due to the large amount and precipitation intensity of the storm. In addition, the scavenging ratio of water soluble ions was larger than that of organics and gaseous pollutants such as SO_2 and NO_2, likely due to their differences in water solubility.Consequently, raindrops incorporated more aerosol sulfate than gaseous compounds. Due to the heavy precipitation amount, almost all species in rainwater during this storm showed their lowest concentration but the highest flux compared with other rain events, indicating an important role played by this storm in terms of the substances received by the terrestrial and marine ecosystems of the region. However, the contribution of this storm to the annual chemical flux was lower than that of precipitation amount, indicating that the atmospheric compounds were scavenged below-cloud first and were then diluted by the cloud/rainwater. Future studies are needed in the context of the occurrence of extreme rainfall events in the NCP from the perspective of climate variability.
基金Project(2011ZX07303-002)supported by National Water Pollution Control and Management Technology Major Program,China
文摘The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conventional bioretention column(Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer(Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone(Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH+4—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO-3—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3—N.
文摘Climatic factor's effect was studied on the radial growth of teak (Tectona grandis L.F.) by using the stem analysis of 36 trees distributed in 6 plantations in Parakou and Tchaourou districts in northern Benin. The results showed that the plantations of Parakou were in general more productive than those of Tchaourou. The annual average growth was estimated in the first five years at 0.86 cm/year for Parakou and 0.76 cm/year at Tchaourou. The analysis of the radial growth showed that a significant percentage of the variance was allotted to the growth model. It follows that a big part of the ring width was predetermined before the intervention of the other factors, in particular the climatic conditions. The percentage of the variance related to the climatic conditions was thus more reduced for the plantations of Tchaourou than those of Parakou. The radial growth was influenced by the conditions of humidity (evapotranspiration, humidity and rain) of February to May on the one hand and those from August to October on the other hand.
文摘Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as thymol, formic and oxalic acid in different formulations and presentations. This kind of organic products has shown a variable acaricidal capacity, since different factors affect their efficacy such as ambient temperature and humidity, product presentation and location inside the hive, etc.. In Chile, beekeeping takes place in four different climatic zones, in which ambient temperature and humidity as well as the duration of the apicultural season are different. Therefore, the aim of this study was to determine how ambient temperature and humidity influence the efficacy of the organic treatments used in the beekeeping season. Different apiaries were installed in those climatic zones in three seasons between the years 2009 and 2012. All beehives received the same management in each apiary and it was evaluated the same organic treatments in different formulations and presentations. All the beehives were positive to Varroa, which was obtained using samples of adult bees and the soapy water test before and after each treatment. A thermo-hygrometer was installed in each apiary in order to monitor the ambient temperature (T°) and humidity (H°) conditions, which were registered daily for a period of 30 days since the beginning. It was obtained that the treatments' efficacy increases as the minimum T° and average T° rose, whereas on the contrary, the efficacy decreases when maximum H° was higher.
基金Project(2007CB613604) supported by the National Basic Research Program of China
文摘A two-stage ligand selection method composed of a primary selection and a critical selection,for complex-leaching valuable metals was presented.At the primary selection stage,three conditions were discussed under a supposed ideal state by mathematical derivation.Generally,ligands selected under condition Ⅰwere easier for complex-leaching valuable metals than that under conditionⅡ,however,under conditionⅢ,ligands selected were hard to complex-leaching the valuable metals.Ligands that were out of these three conditions could be disposed directly.In critical selection,ligands selected in primary selection can be finalized.Case applications were provided for verifying the method.The application indicated that iminodiacetate(Ida2-)can be used as a complex agent for complex-leaching smithsonite(ZnCO3);the leaching condition should be controlled with pH 8-11;the relative error of the minimum consumption of Ida2-between the predicted and the calculated results is 5.3%.The results indicate that the theoretical derivations in the ideal state are reliable,and the method for ligand selection is practical and operable.
文摘Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have received a large amount of exogenous nitrogen (N) input from the adjacent agricultural land because of fertilization. In the present study, the effects of nitrogen additions on seed germination and seedling biomass of Calamagrostis angustifolia in freshwater marsh were tested in a greenhouse study. Seed bank soil was exposed to different N additions (0, 5, 10, 20 and 40 g/m^2) under non-flooded water regime. Results revealed that, low level of N additions (less than 10 g/m^2) did not significantly affect the species richness and seedling density, while the seedling biomass at 5 g/m^2 of N addition was higher than other nutrient conditions. But species richness, seedling emergence and biomass decreased significantly at high level of N additions (20-40 g/m^2). The responses were species-specific. High level of N additions had negative impacts on seed germination, seedling growth and biomass of dominant species Eleocharis ovata, Calamagrostis angustifolia, duncus effusus in the seed bank. To protect and restore the wetland vegetation community in the Sanjiang plain, fertilization, irrigation and land management strategies will need to be implemented to reduce the nutrient input from the agricultural land to the wetlands.
文摘The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design(OAD) has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows: the temperature range of 70-90 ℃ for reaction temperature(T), 30-90 min for reaction time(t), 2-4 g/L for zinc powder mass concentration(M), one to five series for zinc dust particle size distributions(S1-S5), and 0.1-0.5 g/L(C) for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4(85 ℃), t4=75 min, M4=3.5 g/L, S4(Serie 4), and C2=0.2 g/L.
文摘Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.
文摘This study was conducted to establish a predictable method for a heat load of an underground structure with sufficient accuracy. As the first step, our previous paper reported the measurement results of field experiments on an underground experimental basement under internal heat generation conditions. Also, it presented the results of numerical analyses on the heat and moisture behavior and the influence of internal heat generation of the experimental basement and ground. However, it is practically impossible to utilize the model of simultaneous heat and moisture transfer at the design phase because the prediction by the model of simultaneous heat and moisture transfer requires a long calculation time. In this paper, the authors present the simple load calculation technique, using a linearized approximation indicial response of the inner surface heat flux in a basement to outdoor air temperature change. In addition, the approximation indicial responses for each part of the single-walled concrete drawn using this technique are arranged. The heat load calculation example of application to the basement of the optional size by this technique is shown.
基金supported by the fund for Special Climate Change in 2010 from China Meteorological Administration(No.CCFS-2010)by a grant from the National Natural Science Foundation of China(No.41275097)
文摘Due to climate change, the regional agro-climatic conditions in Southwest China have undergone changes. The heat sources for the growth of crops have been improved. The number of days with temperatures steadily above 0℃ and 10℃ (two criteria) have increased during 1960-2010. The area suitable for multiple cropping has increased; the growth period has shortened; the climatic potential productivity has declined; the pest damage has worsened. During 1986-2010, the desired cooling degree days in Southwest China has increased at 38.9℃ d per decade. Forest fires and pests have increased. The area of meadow and wetlands has decreased. Heterogeneous invasion has intensified; endangered animal and plant species have increased. The tourism landscape has been damaged.' The risk of human health has increased. In the 21st century, with the increase of temperature and precipitation, the number of days with temperature steadily above 10℃ and the accumulated temperature will continue to increase, most notably in the Qinghai-Tibetan Plateau. The area of intercropping will expand; multiple cropping will move to higher altitudes. The impacts of agro- meteorological disasters, pests and diseases will intensify. The summer cooling energy consumption continues to increase; energy supply will show larger variability; the gap between energy supply and demand will be widened. The phenology will keep on changing, and the habitat will be worsening. Biological population will move northward and to higher altitudes. Some species are at risk of extinction. Negative effects on health will increase.
基金supported by the National Natural Science Foundation of China (Grant Nos.10921062 and 10502051)
文摘YBCO superconducting films were prepared by Electron Beam Coevaporation method.All the YBCO films were annealed at 760°C in humidity range of 2.3-?9.5.Microstructure of the YBCO thin films was analyzed by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM).Superconducting properties of the YBCO films were measured by electromagnetic induction method.XRD results showed that c-axis-oriented grains existed in the YBCO films.Morphologies of the YBCO films showed that all the films had a smooth and crack-free surface.YBCO films prepared at 7.3% humidity condition showed Jc value of 4.6 MA cm-2 at 77 K in self-field.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41130103, 41210007)
文摘This paper revealed the climatic change characteristics of fog and haze of different levels over North China and Huang-Huai area(NCHH).It was found that the haze-prone period has changed from winter into a whole year,and the haze days(HD)in winter have increased significantly.The foggy days(FD)are half of HD.There are little difference on the number of days and trends of fog at various levels.The HD and FD show no obvious positive correlation until the 1980s.Fog has larger spatial scale,showing more in the south than in the north.Haze occurs mainly around large cities with a discrete distribution.In the background of weakened East Asian Winter Monsoon(EAWM)and sufficient particulate matter,the negative correlation between haze and wind speed is weakened,but the positive correlation between haze and moisture conditions(precipitation and humidity)is significantly strengthened.In recent years,small wind and variability appear frequently.Meanwhile,as the stable source and strong moisture absorption of the aerosol particles,the moisture condition becomes one key control factor in the haze,especially wet haze with less visibility.In contrast,the FD presents a stable positive correlation with precipitation and relative humidity,but has no obvious negative correlation with wind speed.
基金supported by the National Natural Science Foundation of China(51877132,U19A20105,and 52003153)the Program of Shanghai Academic Research Leader(21XD1401600)。
文摘The long-term safe operation of high-power equipment and integrated electronic devices requires efficient thermal management,which in turn increases the energy consumption further.Hence,the sustainable development of our society needs advanced thermal management with low,even zero,energy consumption.Harvesting water from the atmosphere,followed by moisture desorption to dissipate heat,is an efficient and feasible approach for zero-energy-consumption thermal management.However,current methods are limited by the low absorbance of water,low water vapor transmission rate(WVTR)and low stability,thus resulting in low thermal management capability.In this study,we report an innovative electrospinning method to process hierarchically porous metal–organic framework(MOF)composite fabrics with high-efficiency and zero-energy-consumption thermal management.The composite fabrics are highly loaded with MOF(75 wt%)and their WVTR value can be up to 3138 g m^(-2) d^(-1).The composite fabrics also exhibit stable microstructure and performance.Under a conventional environment(30℃,60%relative humidity),the composite fabrics adsorb water vapor for regeneration within 1.5 h to a saturated value Wsat of 0.614 g g^(-1),and a corresponding equivalent enthalpy of 1705.6 J g^(-1).In the thermal management tests,the composite fabrics show a strong cooling capability and significantly improve the performance of thermoelectric devices,portable storage devices and wireless chargers.These results suggest that hierarchically porous MOF composite fabrics are highly promising for thermal management of intermittent-operation electronic devices.
基金supported by the National Key Technology R & D Program in the 11th Five Year Plan of China (Grant No. 2010BAK67B16)the Outstanding Doctorial Research Scholarship of Lanzhou University (Grant No. )
文摘Water stability of soil is crucial to the durability of earthen monuments,especially those located in the humid weather condition.This paper discusses the selection reason of materials(tung oil and quicklime) for earthen monument treatment,and then validates the applicability of these materials with tests of soil-water characteristic curve(SWCC),aggregate stability test(AST) and scanning electron microscope(SEM).The soil tested was sampled from Da Bao'en temple in Nanjing,Jiangsu province,China.The test results indicate that the carbonation reaction of quicklime offers a favorable environment for the formation of tung oil film.Meanwhile,the regulatory function of tung oil restricts the crystallinity of calcium carbonate(CaCO3) and forms fine crystals.Soil treated with both of tung oil and quicklime has good water repellency and aggregate stability without obvious changing in aesthetic appearance.Hydrophobicity and carbonation treatment can be applied prospectively in the conservation of earthen monument located in humid weather condition.