The residence-time distribution (RTD) and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematic...The residence-time distribution (RTD) and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematical model as well as three-dimensional computational fluid dynamics (CFD) model was established to analyze the flow regions of feedwells on an industrial scale. The concept of RTD, although a well-known method for the characterization of mixing behavior in conventional mixers and reactors, is still a novel measure for the characterization of mixing in feedwells. Numerical simulation results show that the inlet feed rate and the aspect ratio of feedwells are the most critical parameters which affect the RTD of feedwell. Further simulation experiments were then carried out. Under the optimal operation conditions, the volume fraction of dead zone can reduce by10.8% and an increasement of mixing flow volume fraction by 6.5% is also observed. There is an optimum feed inlet rate depending on the feedwell design. The CFD model in conjunction with the RTD analysis then can be used as an effective tool in the design, evaluation and optimization of thickener feedwell in the red mud separation.展开更多
NCW(network centric warfare) is an information warfare concentrating on network. A global network-centric warfare architecture with OGSA grid technology is put forward,which is a four levels system including the user ...NCW(network centric warfare) is an information warfare concentrating on network. A global network-centric warfare architecture with OGSA grid technology is put forward,which is a four levels system including the user level, the application level, the grid middleware layer and the resource level. In grid middleware layer,based on virtual hosting environment, a BEPL4WS grid service composition method is introduced. In addition, the NCW grid service model is built with the help of Eclipse-SDK-3.0.1 and Bpws4j.展开更多
Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve (FFR) in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 in...Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve (FFR) in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 intermediate coronary lesions. Pressure-derived FFR of these lesions was gained at maximal hyperemia induced by intravenous adenosine infusion. An FFR 〈 0.80 was considered as abnormal functional significance. Anatomic parameters at the lesion sites were obtained by off-line quantitative coronary angiography analysis (QCA). The predictive value of the demographic characteristics and anatomic parameters for FFR in these intermediate lesions was assessed using multiple linear and binary logistic regression analysis. Results Overall, FFR 〈 0.8 was found in 70 (34%) of the total 203 intermediate coronary lesions. FFR values were positively correlated with QCA-measured minimum lumen diameters (MLD, r = 0.372, P = 0.000) and the reference vessel diameters (RVD, r = 0.217, P〈 0.002) were negatively correlated with percent area stenosis (AS, r = -0.251, P = 0.000) and percent diameter stenosis (DS, r = -0.210, P = 0.000). Age, MLD and the lesion location in different coronary arteries were the inde- pendent determinants of FFR 〈 0.8. Conclusions MLD can predict the functional significance of intermediate coronary stenosis, while age and the lesion location in different coronary arteries should be taken into account as important influencing factors of FFR values.展开更多
Objective.To determine the apoptotic and proliferative activities in various ovarian epithelial tumors.Methods.Formalin-fixed,paraffin-embedded tissues of 86ovarian epithelial tu mors,including 52adenocarcino-mas,23bo...Objective.To determine the apoptotic and proliferative activities in various ovarian epithelial tumors.Methods.Formalin-fixed,paraffin-embedded tissues of 86ovarian epithelial tu mors,including 52adenocarcino-mas,23borderline tumors and 11cystadenomas,were retrieved.Apoptoti c(AI )and proliferative(PI )index were estimated using the monoclonal antibodies:M30,Ki-67and Ki-S1in t hese tumors.Quantitative assess-ment of AI and PI was estimated by calc ulating the percentage of positive c ells among no less than 1000tumor cells.Results.Statistically significant differe nce in AI was found between benign and borderline tumors or carcino-mas(P=0.028,0.001,respectively).Significant differences in PI,as a ssessed by both Ki-67and topo IIα,were demonstrated between carcinom as and benign or borderline tumors(both P<0.001).Benign tumors had both low PI and AI;borderline tumors had lower PI but higher AI,while aden ocarcinomas had both high prolifera-tive and high apoptotic rates.Among borderline tumors,serous tumors had significantly lower AI and higher PI than mucinous ones.Conclusions.The results suggest that apoptotic a nd proliferative activities play im portant roles in the pathogene-sis and development of ovarian borderline and malignant tumors.The high apoptotic rate in borderline tumor m ay explain its relatively indolent beh avior while the high proliferative r ate in carcinomas tends to explain its aggres-sive behavior.展开更多
Recently, the demand of services for architectural space is more increasing due to the diversification and complication of people's needs. In this research, it is assumed that the robot will support people's various...Recently, the demand of services for architectural space is more increasing due to the diversification and complication of people's needs. In this research, it is assumed that the robot will support people's various needs and people's lives in the near future. In this study, the authors investigated the relationship between a robot and a person in quasi space close to actual life space. The authors carried out an experiment to clarify the feelings of worriment due to a robot in the living room in the case of Japanese males. This research aims to establish architecture techniques for robots and humans living together. In this experiment, the robot approached a male sitting on a sofa in quasi space. At different distances between the robot and the male, the subject evaluated his feelings of worriment from "no worriment" to "worriment" in five steps from one to five. The robot used in this experiment is middle-sized (380 mm (L) × 380 mm (W) × 350 mm (H)). In this experiment, it is considered that the robot asks for help outside when an emergency occurs. In this experiment, the authors had three situations for the subject: watching television, reading a magazine and just sitting.展开更多
Based on GISS-E2-R model simulations, the changes in PM2.5 and ozone concentrations during 2016– 35 are analyzed over the Jing-Jin-Ji region under different future emissions scenarios: 2.6, 4.5, 6.0, 8.5 Representati...Based on GISS-E2-R model simulations, the changes in PM2.5 and ozone concentrations during 2016– 35 are analyzed over the Jing-Jin-Ji region under different future emissions scenarios: 2.6, 4.5, 6.0, 8.5 Representative Concentration Pathways scenarios(RCP2.6, RCP4.5, RCP6.0, and RCP8.5), compared to the baseline periods of 1851–70(pre-industrial) and 1986–2005(present day). The results show that PM2.5 increases under all emissions scenarios, with the maximum value occurring in the southeastern part of the region under most scenarios. As for ozone, its concentration is projected to increase during 2016–35 under all emissions scenarios, compared to the baseline periods. The temporal evolutions of PM2.5 and ozone show PM2.5 reaching a peak during 2020–40, while ozone will likely increase steadily in the future.展开更多
Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized s...Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized substructures;and the cold-rolled sheet was characterized by a "pan-caked" grain structure containing high density dislocation cells.The product under near peak-aging temper is proved to contain a large amount of dispersive,plate-shaped T1(Al2CuLi) precipitates,together with a small fraction of θ'(Al2Cu) plates,exhibiting a desirable combination of mechanical properties.Analyses using scanning electron microscopy reveal that many coarse,irregular-shaped Al7Cu2Fe constituent particles exist in all product states,which indicates that intermediate heat treatments have little influence on this iron-caused,detrimental phase.The formation and evolution of microstructures for different product states of alloy 2195 were discussed in view point of the commercial production condition.展开更多
In order to achieve large tolerance capture and high stiffness connection for space payload operations,a Chinese large-scale space end-effector (EER) was developed.Three flexible steel cables were adopted to capture t...In order to achieve large tolerance capture and high stiffness connection for space payload operations,a Chinese large-scale space end-effector (EER) was developed.Three flexible steel cables were adopted to capture the payload with large capture allowance.Ball screw transmission mechanism and plane shape-constraint four bar linkage mechanism were utilized to connect the payload with high stiffness.The experiments show that capture tolerances in X,Y,Z,Pitch,Yaw,Roll directions are 100 mm,100 mm,120 mm,10.5°,10.5°,12°,respectively.The maximum connection stiffness is 4 800 N·m.The end-effector could meet the requirements for space large tolerance capture and high stiffness connection in the future.展开更多
Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress p...Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress paths were designed,a commonly used stress path in true triaxial unloading rockburst tests and a new test path in which the intermediate principal stress was varied.During the tests,a high-speed camera was used to record the strainburst process,and an acoustic emission(AE)monitoring system was used to monitor the AE characteristics of failure.In these two stress paths,all the marble specimens exhibited strainbursts;however,when the intermediate principal stress was varied,the rockburst became more violent.The obtained results indicate that the intermediate principal stress has a significant effect on rockburst behavior of marble.Under a higher intermediate principal stress before the unloading,more elastic strain energy was accumulated in the specimen,and the cumulative AE energy was higher in the rockburst-induced failure,i.e.,more elastic strain energy was released during the failure.Therefore,more violent failure was observed:more rock fragments with a higher mass and larger size were ejected outward.展开更多
The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts...The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts, further studies are still needed to understand the regional consequences between the two global warming limits. Here we provide an assessment of changes in temperature extremes over China (relative to 1986-2005) at 1.5 ℃ and 2 ℃ warming levels (relative to 1861-1900) by using the 5th phase of the Coupled Model Intercomparison Project (CMIP5) models under three RCP scenarios (RCP2.6, RCP4.5, RCP8.5). Results show that the increases in mean temperature and temperature extremes over China are greater than that in global mean temperature. With respect to 1986-2005, the temperature of hottest day (TXx) and coldest night (TNn) are projected to increase about 1/1.6 ℃ and 1.1/1.8 ℃, whereas warm days (TX90p) and warm spell duration (WSDI) will increase about 7.5/13.8% and 15/30 d for the 1.5/2 ℃ global warming target, respectively. Under an additional 0.5 ℃ global warming, the projected increases of temperature in warmest day/night and coldest day/night are both more than 0.5 ℃ across almost the whole China. In Northwest China, Northeast China and the Tibetan Plateau, the projected changes are particularly sensitive to the additional 0.5 ℃ global warming, for example, multi-model mean increase in coldest day (TXn) and coldest night (TNn) will be about 2 times higher than a change of 0.5 ℃ global warming. Although the area-averaged changes in temperature extremes are very similar for different scenarios, spatial hotspot still exists, such as in Northwest China and North China, the increases in temperatures are apparently larger in RCP8.5 than that in RCP4.5.展开更多
The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively popu...The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively population data with other data including natural resources, environment, society and economy, build 1km GRIDs of natural resources reserves per person, population density and other economic and environmental data, which are necessary to the national management and macro adjustment and control of natural resources and dynamic monitoring of population. In order to establish population information system serving national decision making, three steps ought to be followed:1) establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolution using topographical map with large scale and high resolution satellite remote sensing data, the determination of attribute information of housing and office buildings, and creating complete set of attribute database and rapid data updating; 2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database, meanwhile, the government should attach great importance to the establishment and integration of population migration database; 3) considering there is no GIS software specially serving the analysis and management of population data, a practical approach is to add special modules to present software system, which works as a bridge actualizing the digitization and spatialization of population geography research.展开更多
A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the supp...A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time θm. It is demonstrated that Rm is nearly a constant for a given filter cloth.展开更多
In wireless sensor networks,node localization is a fundamental middleware service.In this paper,a robust and accurate localization algorithm is proposed,which uses a novel iterative clustering model to obtain the most...In wireless sensor networks,node localization is a fundamental middleware service.In this paper,a robust and accurate localization algorithm is proposed,which uses a novel iterative clustering model to obtain the most representative intersection points between every two circles and use them to estimate the position of unknown nodes.Simulation results demonstrate that the proposed algorithm outperforms other localization schemes (such as Min-Max,etc.) in accuracy,scalability and gross error tolerance.展开更多
基金Project (50876116) supported by the National Natural Science Foundation of China
文摘The residence-time distribution (RTD) and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematical model as well as three-dimensional computational fluid dynamics (CFD) model was established to analyze the flow regions of feedwells on an industrial scale. The concept of RTD, although a well-known method for the characterization of mixing behavior in conventional mixers and reactors, is still a novel measure for the characterization of mixing in feedwells. Numerical simulation results show that the inlet feed rate and the aspect ratio of feedwells are the most critical parameters which affect the RTD of feedwell. Further simulation experiments were then carried out. Under the optimal operation conditions, the volume fraction of dead zone can reduce by10.8% and an increasement of mixing flow volume fraction by 6.5% is also observed. There is an optimum feed inlet rate depending on the feedwell design. The CFD model in conjunction with the RTD analysis then can be used as an effective tool in the design, evaluation and optimization of thickener feedwell in the red mud separation.
文摘NCW(network centric warfare) is an information warfare concentrating on network. A global network-centric warfare architecture with OGSA grid technology is put forward,which is a four levels system including the user level, the application level, the grid middleware layer and the resource level. In grid middleware layer,based on virtual hosting environment, a BEPL4WS grid service composition method is introduced. In addition, the NCW grid service model is built with the help of Eclipse-SDK-3.0.1 and Bpws4j.
文摘Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve (FFR) in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 intermediate coronary lesions. Pressure-derived FFR of these lesions was gained at maximal hyperemia induced by intravenous adenosine infusion. An FFR 〈 0.80 was considered as abnormal functional significance. Anatomic parameters at the lesion sites were obtained by off-line quantitative coronary angiography analysis (QCA). The predictive value of the demographic characteristics and anatomic parameters for FFR in these intermediate lesions was assessed using multiple linear and binary logistic regression analysis. Results Overall, FFR 〈 0.8 was found in 70 (34%) of the total 203 intermediate coronary lesions. FFR values were positively correlated with QCA-measured minimum lumen diameters (MLD, r = 0.372, P = 0.000) and the reference vessel diameters (RVD, r = 0.217, P〈 0.002) were negatively correlated with percent area stenosis (AS, r = -0.251, P = 0.000) and percent diameter stenosis (DS, r = -0.210, P = 0.000). Age, MLD and the lesion location in different coronary arteries were the inde- pendent determinants of FFR 〈 0.8. Conclusions MLD can predict the functional significance of intermediate coronary stenosis, while age and the lesion location in different coronary arteries should be taken into account as important influencing factors of FFR values.
文摘Objective.To determine the apoptotic and proliferative activities in various ovarian epithelial tumors.Methods.Formalin-fixed,paraffin-embedded tissues of 86ovarian epithelial tu mors,including 52adenocarcino-mas,23borderline tumors and 11cystadenomas,were retrieved.Apoptoti c(AI )and proliferative(PI )index were estimated using the monoclonal antibodies:M30,Ki-67and Ki-S1in t hese tumors.Quantitative assess-ment of AI and PI was estimated by calc ulating the percentage of positive c ells among no less than 1000tumor cells.Results.Statistically significant differe nce in AI was found between benign and borderline tumors or carcino-mas(P=0.028,0.001,respectively).Significant differences in PI,as a ssessed by both Ki-67and topo IIα,were demonstrated between carcinom as and benign or borderline tumors(both P<0.001).Benign tumors had both low PI and AI;borderline tumors had lower PI but higher AI,while aden ocarcinomas had both high prolifera-tive and high apoptotic rates.Among borderline tumors,serous tumors had significantly lower AI and higher PI than mucinous ones.Conclusions.The results suggest that apoptotic a nd proliferative activities play im portant roles in the pathogene-sis and development of ovarian borderline and malignant tumors.The high apoptotic rate in borderline tumor m ay explain its relatively indolent beh avior while the high proliferative r ate in carcinomas tends to explain its aggres-sive behavior.
文摘Recently, the demand of services for architectural space is more increasing due to the diversification and complication of people's needs. In this research, it is assumed that the robot will support people's various needs and people's lives in the near future. In this study, the authors investigated the relationship between a robot and a person in quasi space close to actual life space. The authors carried out an experiment to clarify the feelings of worriment due to a robot in the living room in the case of Japanese males. This research aims to establish architecture techniques for robots and humans living together. In this experiment, the robot approached a male sitting on a sofa in quasi space. At different distances between the robot and the male, the subject evaluated his feelings of worriment from "no worriment" to "worriment" in five steps from one to five. The robot used in this experiment is middle-sized (380 mm (L) × 380 mm (W) × 350 mm (H)). In this experiment, it is considered that the robot asks for help outside when an emergency occurs. In this experiment, the authors had three situations for the subject: watching television, reading a magazine and just sitting.
基金support from the R&D Special Fund for Public Welfare Industry (Meteorology) (Grant No. GYHY201306019)the National Natural Science Foundation of China (Grant No. 41275078)+1 种基金the Grant Projects of China Clean Development Mechanism Fund (Grant No. 121312)the Climate Change Foundation of China Meteorological Administration (Grant No. CCSF201339)
文摘Based on GISS-E2-R model simulations, the changes in PM2.5 and ozone concentrations during 2016– 35 are analyzed over the Jing-Jin-Ji region under different future emissions scenarios: 2.6, 4.5, 6.0, 8.5 Representative Concentration Pathways scenarios(RCP2.6, RCP4.5, RCP6.0, and RCP8.5), compared to the baseline periods of 1851–70(pre-industrial) and 1986–2005(present day). The results show that PM2.5 increases under all emissions scenarios, with the maximum value occurring in the southeastern part of the region under most scenarios. As for ozone, its concentration is projected to increase during 2016–35 under all emissions scenarios, compared to the baseline periods. The temporal evolutions of PM2.5 and ozone show PM2.5 reaching a peak during 2020–40, while ozone will likely increase steadily in the future.
基金supported by the National Key Technologies R&D Program of China during the 10th Five-year Plan Period
文摘Microstructures of three kinds of typical product states for commercially fabricated alloy 2195 were observed.It is found that the hot-rolled plate is characterized by a fibrous structure containing fine,polygonized substructures;and the cold-rolled sheet was characterized by a "pan-caked" grain structure containing high density dislocation cells.The product under near peak-aging temper is proved to contain a large amount of dispersive,plate-shaped T1(Al2CuLi) precipitates,together with a small fraction of θ'(Al2Cu) plates,exhibiting a desirable combination of mechanical properties.Analyses using scanning electron microscopy reveal that many coarse,irregular-shaped Al7Cu2Fe constituent particles exist in all product states,which indicates that intermediate heat treatments have little influence on this iron-caused,detrimental phase.The formation and evolution of microstructures for different product states of alloy 2195 were discussed in view point of the commercial production condition.
基金Project(2006AA04Z228) supported by the National High Technology Research and Development Program of China
文摘In order to achieve large tolerance capture and high stiffness connection for space payload operations,a Chinese large-scale space end-effector (EER) was developed.Three flexible steel cables were adopted to capture the payload with large capture allowance.Ball screw transmission mechanism and plane shape-constraint four bar linkage mechanism were utilized to connect the payload with high stiffness.The experiments show that capture tolerances in X,Y,Z,Pitch,Yaw,Roll directions are 100 mm,100 mm,120 mm,10.5°,10.5°,12°,respectively.The maximum connection stiffness is 4 800 N·m.The end-effector could meet the requirements for space large tolerance capture and high stiffness connection in the future.
基金Project(2016YFC0801403) supported by the National Key Research and Development Program of ChinaProject(2017RCJJ012) supported by the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents,China+1 种基金Project(ZR2018MEE009) supported by the Shandong Provincial Natural Science Foundation,ChinaProject(MDPC2017ZR04) supported by the Open Project Fund for State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology of China
文摘Strainburst is one type of rockburst that generally occurs in deep tunnel.In this study,the strainburst behaviors of marble specimens were investigated under tunnel-excavation-induced stress condition,and two stress paths were designed,a commonly used stress path in true triaxial unloading rockburst tests and a new test path in which the intermediate principal stress was varied.During the tests,a high-speed camera was used to record the strainburst process,and an acoustic emission(AE)monitoring system was used to monitor the AE characteristics of failure.In these two stress paths,all the marble specimens exhibited strainbursts;however,when the intermediate principal stress was varied,the rockburst became more violent.The obtained results indicate that the intermediate principal stress has a significant effect on rockburst behavior of marble.Under a higher intermediate principal stress before the unloading,more elastic strain energy was accumulated in the specimen,and the cumulative AE energy was higher in the rockburst-induced failure,i.e.,more elastic strain energy was released during the failure.Therefore,more violent failure was observed:more rock fragments with a higher mass and larger size were ejected outward.
基金We acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in Table l) for producing and making available their model output. This research is supported by the National Key Research and Development Program of China (2017YFA0603804) and the State Key Program of National Natural Science Foundation of China (41230528).
文摘The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts, further studies are still needed to understand the regional consequences between the two global warming limits. Here we provide an assessment of changes in temperature extremes over China (relative to 1986-2005) at 1.5 ℃ and 2 ℃ warming levels (relative to 1861-1900) by using the 5th phase of the Coupled Model Intercomparison Project (CMIP5) models under three RCP scenarios (RCP2.6, RCP4.5, RCP8.5). Results show that the increases in mean temperature and temperature extremes over China are greater than that in global mean temperature. With respect to 1986-2005, the temperature of hottest day (TXx) and coldest night (TNn) are projected to increase about 1/1.6 ℃ and 1.1/1.8 ℃, whereas warm days (TX90p) and warm spell duration (WSDI) will increase about 7.5/13.8% and 15/30 d for the 1.5/2 ℃ global warming target, respectively. Under an additional 0.5 ℃ global warming, the projected increases of temperature in warmest day/night and coldest day/night are both more than 0.5 ℃ across almost the whole China. In Northwest China, Northeast China and the Tibetan Plateau, the projected changes are particularly sensitive to the additional 0.5 ℃ global warming, for example, multi-model mean increase in coldest day (TXn) and coldest night (TNn) will be about 2 times higher than a change of 0.5 ℃ global warming. Although the area-averaged changes in temperature extremes are very similar for different scenarios, spatial hotspot still exists, such as in Northwest China and North China, the increases in temperatures are apparently larger in RCP8.5 than that in RCP4.5.
文摘The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively population data with other data including natural resources, environment, society and economy, build 1km GRIDs of natural resources reserves per person, population density and other economic and environmental data, which are necessary to the national management and macro adjustment and control of natural resources and dynamic monitoring of population. In order to establish population information system serving national decision making, three steps ought to be followed:1) establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolution using topographical map with large scale and high resolution satellite remote sensing data, the determination of attribute information of housing and office buildings, and creating complete set of attribute database and rapid data updating; 2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database, meanwhile, the government should attach great importance to the establishment and integration of population migration database; 3) considering there is no GIS software specially serving the analysis and management of population data, a practical approach is to add special modules to present software system, which works as a bridge actualizing the digitization and spatialization of population geography research.
文摘A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time θm. It is demonstrated that Rm is nearly a constant for a given filter cloth.
基金supported in part by the Key Program of National Natural Science Foundation of China(Grant No.60873244,60973110,61003307)the Beijing Municipal Natural Science Foundation(Grant No.4102059)
文摘In wireless sensor networks,node localization is a fundamental middleware service.In this paper,a robust and accurate localization algorithm is proposed,which uses a novel iterative clustering model to obtain the most representative intersection points between every two circles and use them to estimate the position of unknown nodes.Simulation results demonstrate that the proposed algorithm outperforms other localization schemes (such as Min-Max,etc.) in accuracy,scalability and gross error tolerance.