The ecological footprint (EF) model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and export...The ecological footprint (EF) model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and exports in China were analyzed from 1973 to 2003, the analysis results showed an apparent fluctuation in timber production during 1973-1995 but a decreasing trend during 1995-2002, an increasing trend in timber imports since 1995 especially after the implementation of the Natural Forest Protection Project (NFPP), an decreasing trend year by year in timber exports since 1995. Secondly, this paper presented a time series analysis of actual forest area demand in the sustainable yield and production approach in China from 1973 to 2003, which includes both import and export forest area demand. The results showed the actual forest area demand simulated from the sustainable yield approach was slightly higher than that from the production approach during 1978-1988 and a little lower during 1989-2003; however, the actual forest area demands simulated by these two model approaches were larger than calculations that expressed in conventional forest EF. Meanwhile, the results indicated the forestry development in China during 1978-1988 was unsustainable due to overexploitation of forest stocking volumes, and China's forestry moved toward sustainable development since 1989 because forest resources are exploited at lower rates than they are regenerated. However, compared to forestry developed countries, the forestry development capacity in China is still lower. Finally, based on the model results we analyzed the relationships between forestry EF and the key policies, including trade policy, economic policy and forest conservation programs. In addition, several suggestions about reducing forestry EF and enhancing sustainable forestry development in China are given.展开更多
The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized....The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized.Combined with the trend of related technology,the future development of solar greenhouse meteorological service was prospected.展开更多
Tourist's satisfaction degree is one of the important indexes to evaluate the service quality of scenic spot.Taking Xi'an Dongda Hot Spring Resort Area for an example,with the expectation difference theory and...Tourist's satisfaction degree is one of the important indexes to evaluate the service quality of scenic spot.Taking Xi'an Dongda Hot Spring Resort Area for an example,with the expectation difference theory and customers' satisfaction evaluation model as the theoretical basis of the research,the overall satisfaction degree of tourists to hot spring resort area,and the actual sensation accomplishments and the expectation difference of each service index were analyzed by using regression analysis and paired sample t test method.The results showed:① The overall satisfaction degree of tourists to the resort area was higher.There were remarkable correlation among three variables:the sensation value,the overall satisfaction degree,and the tourist's loyalty degree;② Generally,the sensation actual accomplishments of 15 service appraisal factors were higher than the expectation value.According to the characteristics,these 15 service appraisal factors were divided into 5 groups.Some unsatisfactory aspects were found out,and the corrective measures were put forward.展开更多
Definitions and features of eco-park and theme park were introduced as well as their differences, it was proposed that by applying cultural themes suited to regional ecological resources in the construction of eco-par...Definitions and features of eco-park and theme park were introduced as well as their differences, it was proposed that by applying cultural themes suited to regional ecological resources in the construction of eco-park, the eco-park could achieve not only desired ecological benefits, but also social and economic benefits, and the optimal comprehensive benefits. Design of Baiyunzhai Demonstration Eco-park was taken for an example, integration of eco-park and farming culture was confirmed as the nature, principles of "adaptation to actual conditions, amended protection and construction of plant system" proposed, three functional areas of "Colorful Forest Belt, Yiyun Health Maintenance Zone, Lakefront Meditation Zone" are given on the basis of actual terrains, planning highlights and desired landscape effects expounded to promote the value of regional cultures in Chongqing by building Baiyunzhai Eco-park.展开更多
第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove...第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove the lactic acid from a tired muscle,it willbe able to start working again at once.展开更多
Ⅰ.文学常识1.Calvinism (加尔文主义) -It is the theological system of John Calvin. Its key principle is that God, not man, is central and supreme. Hence scripture is the source of doctrine.2. original sin (原罪)-In Chr...Ⅰ.文学常识1.Calvinism (加尔文主义) -It is the theological system of John Calvin. Its key principle is that God, not man, is central and supreme. Hence scripture is the source of doctrine.2. original sin (原罪)-In Christian theology, it is the state of sinfulness in which all mankind展开更多
An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo...An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.展开更多
1.Is the belief that marriage is between a man and a woman—until recently common even in liberal circles—now presumed so bigoted as to deserve no consideration,even when the exercise of this belief does not actually...1.Is the belief that marriage is between a man and a woman—until recently common even in liberal circles—now presumed so bigoted as to deserve no consideration,even when the exercise of this belief does not actually keep gays from marrying?(Washington News,Feb.24,2014)翻译:婚姻是男女之间的结合,这种观念直到最近就算在思想开明的圈子里都很常见。即便这种观念并不妨碍同性恋者结婚,如今难道也被认为古板而不值得考虑吗?展开更多
EFL motivation is a hot research field of second language learners.In recent years,many researchers have focused on Dornyei’s second language self-system as a theoretical framework.The purpose of this study is to exa...EFL motivation is a hot research field of second language learners.In recent years,many researchers have focused on Dornyei’s second language self-system as a theoretical framework.The purpose of this study is to examine the predictive power of self-orientation of college medium level English learners to EFL learners’motivation,and to find ways to enhance their motivation and EFL proficiency.The subject of this paper is a medium level students of an ordinary college.Using linear regression analysis to collect data through questionnaires,it is found that the self-orientation of the subjects can explain the predictive effect on the actu⁃al learning behavior is not ideal.Ideal L2 self and L2 self-confidence are insufficient,and corresponding learning strategies are lacking,which limits self-directed ability to predict L2 motivation.展开更多
As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model w...As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration(ET0)in 2014 in subalpine meadows of the Qilian Mountains,Northwest China.Meanwhile,actual ET(ETc)was also investigated by the eddy covariance(EC)system.Results indicated that ETc estimated by the EC System was 583 mm,lower than ET0(923 mm)estimated by the FAO Penman-Monteith model in 2014.Moreover,ET0 began to increase in March and reached the peak value in August and then declined in September,however,ETc began to increase from April and reached the peak value in July,and then declined in August.Total ETc and ET0 values during the growing season(from May to September)were 441 and 666 mm,respectively,which accounted for 75.73%of annual cumulative ETc and 72.34%of annual cumulative ET0,respectively.A crop coefficient(kc)was also estimated for calculating the ETc,and average value of kc during the growing season was 0.81(ranging from 0.45 to 1.16).Air temperature(Ta),wind speed(u),net radiation(Rn)and soil temperature(Ts)at the depth of 5 cm and aboveground biomass were critical factors for affecting kc,furthermore,a daily empirical kc equation including these main driving factors was developed.Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.展开更多
In order to predict the actual adsorption amount as gas adsorption reaches the equilibrium,this research designed a dynamic gas adsorption experiment under constant temperature and pressure,and also studied the isopie...In order to predict the actual adsorption amount as gas adsorption reaches the equilibrium,this research designed a dynamic gas adsorption experiment under constant temperature and pressure,and also studied the isopiestic adsorption characteristics of coal samples with same quality but different sizes.Through the experiment,the study found the adsorption-time changing relationships under different pressures of four different size samples.After regression analysis,we obtained the functional relationship between adsorption and time.According to this,the research resulted in the actual adsorption amount when gas adsorption reaches the equilibrium.In addition,the current study obtained the relationship between adsorption and pressure as well as the effect of the coal size to the adsorption rate.These results have great theoretical and practical significance for the prediction of gas amount in coal seam and gas adsorption process.展开更多
Pan evaporation,an indictor of potential evaporation,has decreased during the last several decades in many parts of the world;the trend is contrary to the expectation that the increase of actual evaporation will accom...Pan evaporation,an indictor of potential evaporation,has decreased during the last several decades in many parts of the world;the trend is contrary to the expectation that the increase of actual evaporation will accompany global warming,known as the pan evaporation paradox.What is the essential relationship between pan evaporation and actual evaporation? This is still an uncertain problem.In this paper,the trends of pan evaporation and actual evaporation are investigated using observational data and observation-constrained simulation results using NCAR Community Land Model(CLM) in Xinjiang from 1960 to 2005.Our analysis suggests that the decreasing trend of annual pan evaporation accompanies the increasing trend of annual actual evaporation,the tendencies of them both have statistical significance(at 99% level and at 95% level,respectively).We also find that there is the same turning point in precipitation,pan evaporation and actual evaporation of 1986,and either before the point or after,pan evaporation has inverse trend comparing with actual evaporation and precipitation.The above analysis indicates that pan evaporation and actual evaporation have complementary relationship.These results support the issue of evaporation paradox described by Brutsaert and Parlange(1998) and suggest that decrease of pan evaporation indicates an increase of actual evaporation in Xinjiang in the past half century.The correlation analysis shows that diurnal temperature range(DTR),wind speed,low cloud cover and precipitation are the most likely driving forces for the reduced pan evaporation and the ascending actual evaporation.展开更多
Lost foam casting(LFC)technology has been widely applied to cast iron and cast steel.However,the development of LFC for Al and Mg alloys was relatively slower than that for cast iron and cast steel.The application of ...Lost foam casting(LFC)technology has been widely applied to cast iron and cast steel.However,the development of LFC for Al and Mg alloys was relatively slower than that for cast iron and cast steel.The application of LFC to Al and Mg alloys needs more effort,especially in China.In this paper,the development history of LFC is reviewed,and the application situations of LFC to Al and Mg alloys are mainly discussed.Meanwhile,the key problems of LFC for Al and Mg alloys are also pointed out.Finally,the prospects for LFC technology are discussed,and some special new LFC technologies are introduced for casting Al and Mg alloys.In future,the development trends of green LFC technology mainly focus on the special new LFC methods,metal material,coating,heat treatment,new foam materials as well as purification technology of tail gas,etc.展开更多
Water storage has important significance for understanding water cycles of global and local domains and for monitoring climate and environmental changes. As a key variable in hydrology, water storage change represents...Water storage has important significance for understanding water cycles of global and local domains and for monitoring climate and environmental changes. As a key variable in hydrology, water storage change represents the sum of precipitation, evaporation, surface runoff, soil water and groundwater exchanges. Water storage change data during the period of 2003-2008 for the source region of the Yellow River were collected from Gravity Recovery and Climate Experiment (GRACE) satellite data. The monthly actual evaporation was estimated according to the water balance equation. The simulated actual evaporation was significantly consistent and correlative with not only the observed pan (20 cm) data, but also the simulated results of the version 2 of Simple Biosphere model. The average annual evaporation of the Tangnaihai Basin was 506.4 mm, where evaporation in spring, summer, autumn and winter was 130.9 mm, 275.2 mm, 74.3 mm and 26.1 mm, and accounted for 25.8%, 54.3%, 14.7% and 5.2% of the average annual evaporation, respectively, The precipitation increased slightly and the actual evaporation showed an obvious decrease. The water storage change of the source region of the Yellow River displayed an increase of 0.51 mm per month from 2003 to 2008, which indicated that the storage capacity has significantly increased, probably caused by the degradation of permafrost and the increase of the thickness of active layers. The decline of actual evaporation and the increase of water storage capacity resulted in the increase of river runoff.展开更多
There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyze...There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.展开更多
Construction of the static admissible residual stress field and searching the optimal field are key tasks in the shakedown analysis methods applying the static theorem. These methods always meet dimension obstacles wh...Construction of the static admissible residual stress field and searching the optimal field are key tasks in the shakedown analysis methods applying the static theorem. These methods always meet dimension obstacles when dealing with complex problems. In this paper, a novel shakedown criterion is proposed employing actual residual stress field based on the static shakedown theorem. The actual residual stress field used here is produced under a specified load path, which is a sequence of proportional loading and unloading from zero to all the vertices of the given load domain. This ensures that the shakedown behavior in the whole load domain can be determined based on the theorem proposed by K6nig. The shakedown criterion is then implemented in numerical shakedown analysis, The actual residual stress fields are calculated by incremental finite element elastic-plastic analysis technique for finite deformation under the specified load path with different load levels. The shakedown behavior and the shakedown limit load are determined according to the proposed criterion. The validation of the criterion is performed by a benchmark shakedown example, which is a square plate with a central hole under biaxial loading. The results are consistent with existing results in the literatures and are validated by full cyclic elastic-plastic finite element analysis. The numerical shakedown analysis applying the proposed criterion avoids processing dimension obstacles and performing full cyclic elastic-plastic analysis under arbitrary load paths which should be accounted for appearing. The effect of material model and geometric changes on shakedown behavior can he considered conveniently.展开更多
The relationships between photochemical reflectance index (PRI) and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parame...The relationships between photochemical reflectance index (PRI) and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parameters. A greenhouse experiment was conducted using cotton and peanut crops under water stress condition. Five cotton and six peanut cultivars were grown using Andosole soil in pots maintained at two water levels; the control and water stress treatment (WS) of 100 and 50% of the daily transpiration, respectively. Higher non-photochemical quenching (NPQ) was exhibited by peanut than that of cotton by the water stress. On the other hand, the decreases of the actual quantum yield of photosystem II (△F/F'm) and PRI by the water stress in cotton were larger than those in peanut. There were positively significant correlation coefficients between PRI and △F/F'm in cotton at noon and in the afternoon including the control and WS. The correlations of PRI with NPQ were negatively significant at noon and in the afternoon for cotton, and in the afternoon for peanut. No clear relationship was found among these parameters in the morning probably due to the diurnal increase in global solar radiation. It was concluded that there would be a possibility to detect the effects of water stress on △F/F'm and NPQ by PRI with some exceptions, although PRI could not note varietals differences in △F/F'm and NPQ for each treatment.展开更多
基金This paper was supported by National Natural Science Foundation of China (70373044&30470302) and Rejuvenation Northeast Program of CAS
文摘The ecological footprint (EF) model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and exports in China were analyzed from 1973 to 2003, the analysis results showed an apparent fluctuation in timber production during 1973-1995 but a decreasing trend during 1995-2002, an increasing trend in timber imports since 1995 especially after the implementation of the Natural Forest Protection Project (NFPP), an decreasing trend year by year in timber exports since 1995. Secondly, this paper presented a time series analysis of actual forest area demand in the sustainable yield and production approach in China from 1973 to 2003, which includes both import and export forest area demand. The results showed the actual forest area demand simulated from the sustainable yield approach was slightly higher than that from the production approach during 1978-1988 and a little lower during 1989-2003; however, the actual forest area demands simulated by these two model approaches were larger than calculations that expressed in conventional forest EF. Meanwhile, the results indicated the forestry development in China during 1978-1988 was unsustainable due to overexploitation of forest stocking volumes, and China's forestry moved toward sustainable development since 1989 because forest resources are exploited at lower rates than they are regenerated. However, compared to forestry developed countries, the forestry development capacity in China is still lower. Finally, based on the model results we analyzed the relationships between forestry EF and the key policies, including trade policy, economic policy and forest conservation programs. In addition, several suggestions about reducing forestry EF and enhancing sustainable forestry development in China are given.
基金Supported by The Project of the Transformation and Popularization of Tianjin Agricultural Technique Achievement (0804170 )Scientific and Technology Achievements Transfer Capital Project (2009GB24160499)
文摘The solar greenhouse's construction and its demand on meteorological service in the process of production management in China were analyzed,and the current situation of meteorological service on it was summarized.Combined with the trend of related technology,the future development of solar greenhouse meteorological service was prospected.
文摘Tourist's satisfaction degree is one of the important indexes to evaluate the service quality of scenic spot.Taking Xi'an Dongda Hot Spring Resort Area for an example,with the expectation difference theory and customers' satisfaction evaluation model as the theoretical basis of the research,the overall satisfaction degree of tourists to hot spring resort area,and the actual sensation accomplishments and the expectation difference of each service index were analyzed by using regression analysis and paired sample t test method.The results showed:① The overall satisfaction degree of tourists to the resort area was higher.There were remarkable correlation among three variables:the sensation value,the overall satisfaction degree,and the tourist's loyalty degree;② Generally,the sensation actual accomplishments of 15 service appraisal factors were higher than the expectation value.According to the characteristics,these 15 service appraisal factors were divided into 5 groups.Some unsatisfactory aspects were found out,and the corrective measures were put forward.
文摘Definitions and features of eco-park and theme park were introduced as well as their differences, it was proposed that by applying cultural themes suited to regional ecological resources in the construction of eco-park, the eco-park could achieve not only desired ecological benefits, but also social and economic benefits, and the optimal comprehensive benefits. Design of Baiyunzhai Demonstration Eco-park was taken for an example, integration of eco-park and farming culture was confirmed as the nature, principles of "adaptation to actual conditions, amended protection and construction of plant system" proposed, three functional areas of "Colorful Forest Belt, Yiyun Health Maintenance Zone, Lakefront Meditation Zone" are given on the basis of actual terrains, planning highlights and desired landscape effects expounded to promote the value of regional cultures in Chongqing by building Baiyunzhai Eco-park.
文摘第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove the lactic acid from a tired muscle,it willbe able to start working again at once.
文摘Ⅰ.文学常识1.Calvinism (加尔文主义) -It is the theological system of John Calvin. Its key principle is that God, not man, is central and supreme. Hence scripture is the source of doctrine.2. original sin (原罪)-In Christian theology, it is the state of sinfulness in which all mankind
基金Project(51274250)supported by the National Natural Science Foundation of ChinaProject(2012BAK09B02-05)supported by the National Key Technology R&D Program during the 12th Five-year Plan of China
文摘An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.
文摘1.Is the belief that marriage is between a man and a woman—until recently common even in liberal circles—now presumed so bigoted as to deserve no consideration,even when the exercise of this belief does not actually keep gays from marrying?(Washington News,Feb.24,2014)翻译:婚姻是男女之间的结合,这种观念直到最近就算在思想开明的圈子里都很常见。即便这种观念并不妨碍同性恋者结婚,如今难道也被认为古板而不值得考虑吗?
文摘EFL motivation is a hot research field of second language learners.In recent years,many researchers have focused on Dornyei’s second language self-system as a theoretical framework.The purpose of this study is to examine the predictive power of self-orientation of college medium level English learners to EFL learners’motivation,and to find ways to enhance their motivation and EFL proficiency.The subject of this paper is a medium level students of an ordinary college.Using linear regression analysis to collect data through questionnaires,it is found that the self-orientation of the subjects can explain the predictive effect on the actu⁃al learning behavior is not ideal.Ideal L2 self and L2 self-confidence are insufficient,and corresponding learning strategies are lacking,which limits self-directed ability to predict L2 motivation.
基金supported by the National Natural Science Foundation of China (41571051, 91425301)
文摘As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration(ET0)in 2014 in subalpine meadows of the Qilian Mountains,Northwest China.Meanwhile,actual ET(ETc)was also investigated by the eddy covariance(EC)system.Results indicated that ETc estimated by the EC System was 583 mm,lower than ET0(923 mm)estimated by the FAO Penman-Monteith model in 2014.Moreover,ET0 began to increase in March and reached the peak value in August and then declined in September,however,ETc began to increase from April and reached the peak value in July,and then declined in August.Total ETc and ET0 values during the growing season(from May to September)were 441 and 666 mm,respectively,which accounted for 75.73%of annual cumulative ETc and 72.34%of annual cumulative ET0,respectively.A crop coefficient(kc)was also estimated for calculating the ETc,and average value of kc during the growing season was 0.81(ranging from 0.45 to 1.16).Air temperature(Ta),wind speed(u),net radiation(Rn)and soil temperature(Ts)at the depth of 5 cm and aboveground biomass were critical factors for affecting kc,furthermore,a daily empirical kc equation including these main driving factors was developed.Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.
基金supported by the State Key Basic Research Program of China(No.2011CB201202)
文摘In order to predict the actual adsorption amount as gas adsorption reaches the equilibrium,this research designed a dynamic gas adsorption experiment under constant temperature and pressure,and also studied the isopiestic adsorption characteristics of coal samples with same quality but different sizes.Through the experiment,the study found the adsorption-time changing relationships under different pressures of four different size samples.After regression analysis,we obtained the functional relationship between adsorption and time.According to this,the research resulted in the actual adsorption amount when gas adsorption reaches the equilibrium.In addition,the current study obtained the relationship between adsorption and pressure as well as the effect of the coal size to the adsorption rate.These results have great theoretical and practical significance for the prediction of gas amount in coal seam and gas adsorption process.
基金National Natural Science Foundation of China, No.40830956 No.40775055+1 种基金 No.40828004 Knowledge Innovation Project of the Chinese Academy of Sciences,No.KZCX3-SW-229
文摘Pan evaporation,an indictor of potential evaporation,has decreased during the last several decades in many parts of the world;the trend is contrary to the expectation that the increase of actual evaporation will accompany global warming,known as the pan evaporation paradox.What is the essential relationship between pan evaporation and actual evaporation? This is still an uncertain problem.In this paper,the trends of pan evaporation and actual evaporation are investigated using observational data and observation-constrained simulation results using NCAR Community Land Model(CLM) in Xinjiang from 1960 to 2005.Our analysis suggests that the decreasing trend of annual pan evaporation accompanies the increasing trend of annual actual evaporation,the tendencies of them both have statistical significance(at 99% level and at 95% level,respectively).We also find that there is the same turning point in precipitation,pan evaporation and actual evaporation of 1986,and either before the point or after,pan evaporation has inverse trend comparing with actual evaporation and precipitation.The above analysis indicates that pan evaporation and actual evaporation have complementary relationship.These results support the issue of evaporation paradox described by Brutsaert and Parlange(1998) and suggest that decrease of pan evaporation indicates an increase of actual evaporation in Xinjiang in the past half century.The correlation analysis shows that diurnal temperature range(DTR),wind speed,low cloud cover and precipitation are the most likely driving forces for the reduced pan evaporation and the ascending actual evaporation.
基金supported by the National Nature Science Foundation of China(NFSC)(No.50275058,50775085,51204124,51375187)the National High Technology Research and Development Program of China(No.2007AA03Z113)
文摘Lost foam casting(LFC)technology has been widely applied to cast iron and cast steel.However,the development of LFC for Al and Mg alloys was relatively slower than that for cast iron and cast steel.The application of LFC to Al and Mg alloys needs more effort,especially in China.In this paper,the development history of LFC is reviewed,and the application situations of LFC to Al and Mg alloys are mainly discussed.Meanwhile,the key problems of LFC for Al and Mg alloys are also pointed out.Finally,the prospects for LFC technology are discussed,and some special new LFC technologies are introduced for casting Al and Mg alloys.In future,the development trends of green LFC technology mainly focus on the special new LFC methods,metal material,coating,heat treatment,new foam materials as well as purification technology of tail gas,etc.
基金funded by the Global Change Research Program of China (2010CB951401)the National Natural Science Foundation of China (41030638, 41121001, 41030527,41130641,and 41201025)the One Hundred Talents Program of the Chinese Academy of Sciences
文摘Water storage has important significance for understanding water cycles of global and local domains and for monitoring climate and environmental changes. As a key variable in hydrology, water storage change represents the sum of precipitation, evaporation, surface runoff, soil water and groundwater exchanges. Water storage change data during the period of 2003-2008 for the source region of the Yellow River were collected from Gravity Recovery and Climate Experiment (GRACE) satellite data. The monthly actual evaporation was estimated according to the water balance equation. The simulated actual evaporation was significantly consistent and correlative with not only the observed pan (20 cm) data, but also the simulated results of the version 2 of Simple Biosphere model. The average annual evaporation of the Tangnaihai Basin was 506.4 mm, where evaporation in spring, summer, autumn and winter was 130.9 mm, 275.2 mm, 74.3 mm and 26.1 mm, and accounted for 25.8%, 54.3%, 14.7% and 5.2% of the average annual evaporation, respectively, The precipitation increased slightly and the actual evaporation showed an obvious decrease. The water storage change of the source region of the Yellow River displayed an increase of 0.51 mm per month from 2003 to 2008, which indicated that the storage capacity has significantly increased, probably caused by the degradation of permafrost and the increase of the thickness of active layers. The decline of actual evaporation and the increase of water storage capacity resulted in the increase of river runoff.
基金Project(2012BAK09B02-05)supported by the National"Twelfth Five"Science and Technology Support Program,ChinaProject(51274250)supported by the National Natural Science Foundation of China+2 种基金Project(2013zzts057)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(11KF02)supported by the Research Fund of the State Key Laboratory of Coal Resources and Mine safety,CUMT,ChinaProject(2012M511417)supported by China Postdoctoral Science Foundation
文摘There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.
基金Supported by National Science and Technology Major Project of China(Grant No.2013ZX04003031)National Natural Science Foundation of China(Grant No.51475408)+1 种基金Hebei Provincial College Innovation Team Leader Training Program of China(Grant No.LJRC012)Hebei Provincial Natural Science Foundation of China(Grant No.E2012203045)
文摘Construction of the static admissible residual stress field and searching the optimal field are key tasks in the shakedown analysis methods applying the static theorem. These methods always meet dimension obstacles when dealing with complex problems. In this paper, a novel shakedown criterion is proposed employing actual residual stress field based on the static shakedown theorem. The actual residual stress field used here is produced under a specified load path, which is a sequence of proportional loading and unloading from zero to all the vertices of the given load domain. This ensures that the shakedown behavior in the whole load domain can be determined based on the theorem proposed by K6nig. The shakedown criterion is then implemented in numerical shakedown analysis, The actual residual stress fields are calculated by incremental finite element elastic-plastic analysis technique for finite deformation under the specified load path with different load levels. The shakedown behavior and the shakedown limit load are determined according to the proposed criterion. The validation of the criterion is performed by a benchmark shakedown example, which is a square plate with a central hole under biaxial loading. The results are consistent with existing results in the literatures and are validated by full cyclic elastic-plastic finite element analysis. The numerical shakedown analysis applying the proposed criterion avoids processing dimension obstacles and performing full cyclic elastic-plastic analysis under arbitrary load paths which should be accounted for appearing. The effect of material model and geometric changes on shakedown behavior can he considered conveniently.
文摘The relationships between photochemical reflectance index (PRI) and the chlorophyll fluorescence parameters were examined to assess suitability of PRI as a remote-sensing tool for the chlorophyll fluorescence parameters. A greenhouse experiment was conducted using cotton and peanut crops under water stress condition. Five cotton and six peanut cultivars were grown using Andosole soil in pots maintained at two water levels; the control and water stress treatment (WS) of 100 and 50% of the daily transpiration, respectively. Higher non-photochemical quenching (NPQ) was exhibited by peanut than that of cotton by the water stress. On the other hand, the decreases of the actual quantum yield of photosystem II (△F/F'm) and PRI by the water stress in cotton were larger than those in peanut. There were positively significant correlation coefficients between PRI and △F/F'm in cotton at noon and in the afternoon including the control and WS. The correlations of PRI with NPQ were negatively significant at noon and in the afternoon for cotton, and in the afternoon for peanut. No clear relationship was found among these parameters in the morning probably due to the diurnal increase in global solar radiation. It was concluded that there would be a possibility to detect the effects of water stress on △F/F'm and NPQ by PRI with some exceptions, although PRI could not note varietals differences in △F/F'm and NPQ for each treatment.