Since the specifications of most of the existing context-sensitive graph grammars tend to be either too intricate or not intuitive, a novel context-sensitive graph grammar formalism, called context-attributed graph gr...Since the specifications of most of the existing context-sensitive graph grammars tend to be either too intricate or not intuitive, a novel context-sensitive graph grammar formalism, called context-attributed graph grammar（CAGG）, is proposed. In order to resolve the embedding problem, context information of a graph production in the CAGG is represented in the form of context attributes of the nodes involved. Moreover, several properties of a set of confluent CAGG productions are characterized, and then an algorithm based on them is developed to decide whether or not a set of productions is confluent, which provides the foundation for the design of efficient parsing algorithms. It can also be shown through the comparison of CAGG with several typical context-sensitive graph grammars that CAGG is more succinct and, at the same time, more intuitive than the others, making it more suitably and effortlessly applicable to the specification of visual languages.展开更多
The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and se...The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years （0.23°C per decade）, the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years.展开更多
In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed thro...In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.展开更多
Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolutio...Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids （TDS） in the groundwater showed a great variation, with 62.5% of the samples being brackish （TDS ≥ 1 000 mg L^-l）. The groundwater system showed a gradual hydro-chemical zonation composed of Na^＋ -HCO3^-, Na^＋ -Mg^2＋ -SO4 ^2 -Cl^-, and Na^＋ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^＋, K^＋, Cl^-, SO^4 , and Ca^2＋, but other processes, such as mixing, Na^＋ exchange for Ca^2＋ and Mg^2＋, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.展开更多
Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrog...Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrogen(TN) and total phosphorus(TP) were determined to analyze the chronology and nutrients change in recent sediment.The results show that 137Cs activities are low(less than 15 Bq/kg) in the two cores,attributed to the 137Cs migration.Based on 210Pb constant rate of supply(CRS) model,the sedimentation accumulation rates range from 0.13 g/(cm2·yr) to 0.76 g/(cm2·yr) in the ZS core,and from 0.10 g/(cm2·yr) to 0.56 g/(cm2·yr) in the THS core.A remarkable increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s.The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s.The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores,respectively.Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.展开更多
It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological process...It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological processes and re- charge ability of various land use types in Guishui River Basin, China （in Beijing Municipality） were analyzed. The impact of land use change was investigated based on water balance modeling, WetSpass and GIS. The results indicate that groundwater recharge accounts for only 21.16% of the precipitation, while 72.54% is lost in the form of evapotranspiration. The annual-lumped groundwater recharge rate decreases in the order of cropland, grassland, urban land, and forest. Land use change has resulted in a decrease of 4 x 106 m3 of yearly groundwater recharge in the study area, with a spatially averaged rate of 100.48 mm/yr and 98.41 mm/yr in 1980 and 2005, respectively. This variation has primarily come from an increase of urban area and rural settlements, as well as a decrease of cropland.展开更多
An analysis was carried out on the seismic activity and the precursory anomaly prior to the earthquakes in Yiliang on September 7,2012. The characteristics of the seismic activity,the dynamic changes of underground fl...An analysis was carried out on the seismic activity and the precursory anomaly prior to the earthquakes in Yiliang on September 7,2012. The characteristics of the seismic activity,the dynamic changes of underground fluid and deformation were investigated. As a result of the investigation,we found that: before the earthquake,the seismicity level of M4. 0earthquakes had enhanced,and seismic gap of a small earthquake had appeared; the precursory anomalies emerged about 1 year before the earthquake; there was phenomenon of short-term anomaly migrating from the periphery to the epicenter area; the imminent anomaly appeared in a relatively concentrated period of time, a week before the earthquake. The research has shown a significant guidance for the analysis and prediction of strong earthquakes( Ml> 5. 0).展开更多
Based on the characteristics of surrounding rocks for deeply inclined roadway affected by argillation and water seepage, a structure model of layer crack plate was established to analyze the shear sliding instability ...Based on the characteristics of surrounding rocks for deeply inclined roadway affected by argillation and water seepage, a structure model of layer crack plate was established to analyze the shear sliding instability mechanism. Through solid mechanics analysis of anchored surrounding rock with defect from water seepage, combined with numerical analysis for instability mechanism under water seepage in deeply inclined roadway, key factors were proposed. Results show that with increasing height of layer crack plate, lateral buckling critical load value for high wall of the roadway decreases; there is a multistage distribution for tensile stress along the anchor bolt with defect under pulling state condition;groundwater seepage seriously affects the strength of surrounding rock of the roadway, to some extent the plastic zone of the high side rises up to 8 m. Finally some support strategies were proposed for the inclined roadway and successfully applied to Haoyuan coal mine in Tiela mining area,western China.展开更多
The well-known Three Gorges Dam(TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution(0.5 c...The well-known Three Gorges Dam(TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution(0.5 cm sampling) grain size analysis and 137 Cs and 210 Pb dating of the DH8-1 core were conducted with core collected from the distal part of a main sink for the modern Yangtze sediment entering the sea, the Min-Zhe Coastal Mud Deposits(MZCMD) on the inner East China Sea shelf. The 137 Cs dating results show that the core DH8-1 formed during 1946–2012 with a mean deposition rate of 0.65 cm yr^(-1), indicating that the 0.5 cm sampling for grain size analysis in this local area could reflect environmental changes generally on a one-year time scale. The mean grain size of DH8-1 core sediment that deposited after 2003 is significantly larger than that deposited during 1988–2002. After ruling out other possible factors, we infer that the sediment coarsening of DH8-1 core after 2003 is attributed to the TGD operation which causes the erosion of the Yangtze subaqueous delta. Specifically, the TGD operation significantly intensifies the declining trend of the Yangtze sediment loads to the sea despite no decreased water discharge, which results in extensive erosion of the Yangtze subaqueous delta. The relatively coarse sediment of the subaqueous delta is eroded and resuspended by ocean dynamics and then transported by coastal current, finally depositing on the MZCMD area. In addition, the general sediment fining of core DH8-1 that deposited during 1988–2002, comparing with 1946–1987, is mainly caused by dam construction and soil and water conservation within the Yangtze catchment. Our findings are helpful for better understanding the effects of such a huge dam as the TGD on a sediment sink like the MZCMD of such a large river as the Yangtze River.展开更多
Rice husk is a major by-product of the rice milling industry. Rice husk is generated as a by-product office processing in rice mills. Rice husk is generally used for domestic purposes like combustion, raw material for...Rice husk is a major by-product of the rice milling industry. Rice husk is generated as a by-product office processing in rice mills. Rice husk is generally used for domestic purposes like combustion, raw material for paper and board, furfural production and silica industries. Rice husk is an important and one of the most commonly available lignocellulosic materials that can be converted to different types of fuels. Heating value of rice husk is 15 MJ/kg which supports its application as energy source. Rice husk is fired in rice husk gasifier. This paper outlines a new design rice husk gasifier explaining the design as well as calculations involved.展开更多
The results presented in this paper are a part of the research results of the thesis ＂research on scientific basis and practice of develop a system of monitoring the impacts of climate change on surface water and gro...The results presented in this paper are a part of the research results of the thesis ＂research on scientific basis and practice of develop a system of monitoring the impacts of climate change on surface water and groundwater＂. Case study： Ma river basin in Vietnam. The results were implemented： （i） data collection, fieldwork survey, synthesis and analysis of information and data; （ii） partitioning the influence degree of climate change and sea level rise to groundwater; （iii） determining criteria to select monitoring routes, location of monitoring groundwater in the condition of climate change and sea level rise and （iv） developing the monitoring system. The research＇s results have practical implications for the water resources management in the context of climate change and sea level rise in Ma river basin.展开更多
The authors examine the quantization commutes with reduction phenomenon for Hamiltonian actions of compact Lie groups on closed symplectic manifolds from the point of view of topological K-theory and K-homology. They ...The authors examine the quantization commutes with reduction phenomenon for Hamiltonian actions of compact Lie groups on closed symplectic manifolds from the point of view of topological K-theory and K-homology. They develop the machinery of K-theory wrong-way maps in the context of orbifolds and use it to relate the quantization commutes with reduction phenomenon to Bott periodicity and the K-theory formulation of the Weyl character formula.展开更多
基金The National Natural Science Foundation of China(No.60571048,60673186,60736015)the National High Technology Researchand Development Program of China(863Program)(No.2007AA01Z178)
文摘Since the specifications of most of the existing context-sensitive graph grammars tend to be either too intricate or not intuitive, a novel context-sensitive graph grammar formalism, called context-attributed graph grammar（CAGG）, is proposed. In order to resolve the embedding problem, context information of a graph production in the CAGG is represented in the form of context attributes of the nodes involved. Moreover, several properties of a set of confluent CAGG productions are characterized, and then an algorithm based on them is developed to decide whether or not a set of productions is confluent, which provides the foundation for the design of efficient parsing algorithms. It can also be shown through the comparison of CAGG with several typical context-sensitive graph grammars that CAGG is more succinct and, at the same time, more intuitive than the others, making it more suitably and effortlessly applicable to the specification of visual languages.
基金supported by the Climate Change Science Foundation of China Meteorological Administration(No.CCSF2011-1)
文摘The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years （0.23°C per decade）, the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years.
文摘In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.
基金Project supported by the National Natural Science Foundation of China (Nos. 40671010 and 40501012).
文摘Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids （TDS） in the groundwater showed a great variation, with 62.5% of the samples being brackish （TDS ≥ 1 000 mg L^-l）. The groundwater system showed a gradual hydro-chemical zonation composed of Na^＋ -HCO3^-, Na^＋ -Mg^2＋ -SO4 ^2 -Cl^-, and Na^＋ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^＋, K^＋, Cl^-, SO^4 , and Ca^2＋, but other processes, such as mixing, Na^＋ exchange for Ca^2＋ and Mg^2＋, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.
基金Under the auspices of National Key Science and Technology Special Program of Water Pollution Control and Treatment (No. 2008ZX07101-012-01)National Natural Science Foundation of China (No. 40902048, 40771197)Jiangsu Natural Sci-ence Foundation (No. BK2009331, BE2008690)
文摘Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrogen(TN) and total phosphorus(TP) were determined to analyze the chronology and nutrients change in recent sediment.The results show that 137Cs activities are low(less than 15 Bq/kg) in the two cores,attributed to the 137Cs migration.Based on 210Pb constant rate of supply(CRS) model,the sedimentation accumulation rates range from 0.13 g/(cm2·yr) to 0.76 g/(cm2·yr) in the ZS core,and from 0.10 g/(cm2·yr) to 0.56 g/(cm2·yr) in the THS core.A remarkable increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s.The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s.The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores,respectively.Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.
基金Under the auspices of National Natural Science Foundation of China (No. 41101033)Program of International S & T Cooperation (No. 2010DFA92400)+1 种基金Beijing Municipal Natural Science Foundation (No. 8082010)Non-profit Industry Financial Program of the Ministry of Water Resources (No. 200901091)
文摘It is important to understand how land use change impacts groundwater recharge, especially for regions that are undergoing rapid urbanization and there is limited surface water. In this study, the hydrological processes and re- charge ability of various land use types in Guishui River Basin, China （in Beijing Municipality） were analyzed. The impact of land use change was investigated based on water balance modeling, WetSpass and GIS. The results indicate that groundwater recharge accounts for only 21.16% of the precipitation, while 72.54% is lost in the form of evapotranspiration. The annual-lumped groundwater recharge rate decreases in the order of cropland, grassland, urban land, and forest. Land use change has resulted in a decrease of 4 x 106 m3 of yearly groundwater recharge in the study area, with a spatially averaged rate of 100.48 mm/yr and 98.41 mm/yr in 1980 and 2005, respectively. This variation has primarily come from an increase of urban area and rural settlements, as well as a decrease of cropland.
文摘An analysis was carried out on the seismic activity and the precursory anomaly prior to the earthquakes in Yiliang on September 7,2012. The characteristics of the seismic activity,the dynamic changes of underground fluid and deformation were investigated. As a result of the investigation,we found that: before the earthquake,the seismicity level of M4. 0earthquakes had enhanced,and seismic gap of a small earthquake had appeared; the precursory anomalies emerged about 1 year before the earthquake; there was phenomenon of short-term anomaly migrating from the periphery to the epicenter area; the imminent anomaly appeared in a relatively concentrated period of time, a week before the earthquake. The research has shown a significant guidance for the analysis and prediction of strong earthquakes( Ml> 5. 0).
基金provided by the Natural Science Foundation of Jiangsu Province(No.BK20141130)the Fundamental Research Funds for the Central Universities(Nos.2014QNB27 and 2010QNB22)
文摘Based on the characteristics of surrounding rocks for deeply inclined roadway affected by argillation and water seepage, a structure model of layer crack plate was established to analyze the shear sliding instability mechanism. Through solid mechanics analysis of anchored surrounding rock with defect from water seepage, combined with numerical analysis for instability mechanism under water seepage in deeply inclined roadway, key factors were proposed. Results show that with increasing height of layer crack plate, lateral buckling critical load value for high wall of the roadway decreases; there is a multistage distribution for tensile stress along the anchor bolt with defect under pulling state condition;groundwater seepage seriously affects the strength of surrounding rock of the roadway, to some extent the plastic zone of the high side rises up to 8 m. Finally some support strategies were proposed for the inclined roadway and successfully applied to Haoyuan coal mine in Tiela mining area,western China.
基金the National Natural Science Foundation of China for its financial support (Nos. 41376052, 41030856, 40906024)
文摘The well-known Three Gorges Dam(TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution(0.5 cm sampling) grain size analysis and 137 Cs and 210 Pb dating of the DH8-1 core were conducted with core collected from the distal part of a main sink for the modern Yangtze sediment entering the sea, the Min-Zhe Coastal Mud Deposits(MZCMD) on the inner East China Sea shelf. The 137 Cs dating results show that the core DH8-1 formed during 1946–2012 with a mean deposition rate of 0.65 cm yr^(-1), indicating that the 0.5 cm sampling for grain size analysis in this local area could reflect environmental changes generally on a one-year time scale. The mean grain size of DH8-1 core sediment that deposited after 2003 is significantly larger than that deposited during 1988–2002. After ruling out other possible factors, we infer that the sediment coarsening of DH8-1 core after 2003 is attributed to the TGD operation which causes the erosion of the Yangtze subaqueous delta. Specifically, the TGD operation significantly intensifies the declining trend of the Yangtze sediment loads to the sea despite no decreased water discharge, which results in extensive erosion of the Yangtze subaqueous delta. The relatively coarse sediment of the subaqueous delta is eroded and resuspended by ocean dynamics and then transported by coastal current, finally depositing on the MZCMD area. In addition, the general sediment fining of core DH8-1 that deposited during 1988–2002, comparing with 1946–1987, is mainly caused by dam construction and soil and water conservation within the Yangtze catchment. Our findings are helpful for better understanding the effects of such a huge dam as the TGD on a sediment sink like the MZCMD of such a large river as the Yangtze River.
文摘Rice husk is a major by-product of the rice milling industry. Rice husk is generated as a by-product office processing in rice mills. Rice husk is generally used for domestic purposes like combustion, raw material for paper and board, furfural production and silica industries. Rice husk is an important and one of the most commonly available lignocellulosic materials that can be converted to different types of fuels. Heating value of rice husk is 15 MJ/kg which supports its application as energy source. Rice husk is fired in rice husk gasifier. This paper outlines a new design rice husk gasifier explaining the design as well as calculations involved.
文摘The results presented in this paper are a part of the research results of the thesis ＂research on scientific basis and practice of develop a system of monitoring the impacts of climate change on surface water and groundwater＂. Case study： Ma river basin in Vietnam. The results were implemented： （i） data collection, fieldwork survey, synthesis and analysis of information and data; （ii） partitioning the influence degree of climate change and sea level rise to groundwater; （iii） determining criteria to select monitoring routes, location of monitoring groundwater in the condition of climate change and sea level rise and （iv） developing the monitoring system. The research＇s results have practical implications for the water resources management in the context of climate change and sea level rise in Ma river basin.
文摘The authors examine the quantization commutes with reduction phenomenon for Hamiltonian actions of compact Lie groups on closed symplectic manifolds from the point of view of topological K-theory and K-homology. They develop the machinery of K-theory wrong-way maps in the context of orbifolds and use it to relate the quantization commutes with reduction phenomenon to Bott periodicity and the K-theory formulation of the Weyl character formula.
