Objective： To construct a lentiviral expression vector for RNA interference （RNAi） of human VIM gene; and assess its gene silencing effect in pancreatic cancer cell line Panc-1. Methods： Three pairs of human VIM g...Objective： To construct a lentiviral expression vector for RNA interference （RNAi） of human VIM gene; and assess its gene silencing effect in pancreatic cancer cell line Panc-1. Methods： Three pairs of human VIM gene short hairpin RNA（shRNA） sequences were designed using a software available on-line and one pair came from document. After synthesis and annealing, four double-stranded oligonucleotides （dsOligo） were cloned into the pGCL-GFP/U6 plasmid, which were subsequently confirmed by polymerase chain reaction （PCR） and DNA sequencing analysis. Real-time PCR and Westemblotting were used to screen the effective pGCL-GFP-shRNA plasmid in 293T cells, then the most effective one was packed into the recombinant lentivirus Lv-VIM-shRNA with lentiviral packing materials pHelper 1.0 and pHelper 2.0 in 293T cells. The titer of lentivirus was determined by hole-by-dilution titer assay. The silencing effect of Lv-VIM-shRNA in Panc-1 calls were validated by real-time PCR and Western-blotting. Results： An effective Lv-VIM-shRNA was successfully constructed. The titer of lentivirus was determined on 2× 10^9TU/mL. The expressions of VIM mRNA and vimentin were down-regluated in the Panc-1 cells infected with Lv-VIM-shRNA. Conclusion： An effective Lv-VIM-shRNA could inhibit the expression of VIM gene in Panc-1 cells in vitro, which provides a tool for investigating the role of VIM gene in the signaling pathway involved in tumorigenesis and progression of pancreatic cancer and searching new therapeutic targets.展开更多
Forest canopy reduces shortwave radiation and increases the incoming longwave radiation to snowpacks beneath forest canopies. Furthermore, the effect of forest canopy may be changed by complex topography. In this pape...Forest canopy reduces shortwave radiation and increases the incoming longwave radiation to snowpacks beneath forest canopies. Furthermore, the effect of forest canopy may be changed by complex topography. In this paper, we measured and simulated the incoming longwave radiation to snow beneath forest at different canopy openness in the west Tianshan Mountains, China(43°16'N, 84°24'E) during spring 2013. A sensitivity study was conducted to explore the way that terrain influenced the incoming longwave radiation to snow beneath forest canopies. In the simulation model, measurement datasets, including air temperature, incoming shortwave radiation above canopy, and longwave radiation enhanced by adjacent terrain, were applied to calculate the incoming longwave radiation to snow beneath forest canopy. The simulation results were consistent with the measurements on hourly scale and daily scale. The effect of longwave radiation enhanced by terrain was important than that of shortwave radiation above forest canopy with different openness except the 20% canopy openness. The longwave radiation enhanced due to adjacent terrain increases with the slope increase and temperature rise. When air temperature(or slope) is relatively low, thelongwave radiation enhanced by adjacent terrain is not sensitive to slope(or air temperature), but the sensitivity increases with the decrease of snow cover area on sunny slope. The effect of longwave radiation is especially sensitive when the snow cover on sunny slope melts completely. The effect of incoming shortwave radiation reflected by adjacent terrain on incoming longwave radiation to snow beneath forest canopies is more slight than that of the enhanced longwave radiation.展开更多
Background Although particulate matter, with diameters 〈 2.5 μm （PM2.5） and 〈 10 μm （PM10）, and other pollutants have been associated with cardiovascular morbidity and mortality, the effect of pollutants on ac...Background Although particulate matter, with diameters 〈 2.5 μm （PM2.5） and 〈 10 μm （PM10）, and other pollutants have been associated with cardiovascular morbidity and mortality, the effect of pollutants on acute myocardial infarctions （AMIs） has rarely been investigated in Asia, especially in Shanghai, China. Methods Between 1 November 2013 and 27 April 2014, 972 patients from the Pudong District, Shanghai City, were assessed by the Emergency Medical Service. A case-crossover design was used to analyze exposure to air pollution and the AMI risk. Exposures to PM2.5, PM10, nitrogen dioxide （NO2）, sulphurdioxide （SO2）, and carbon monoxide （CO） were based on the mean urban background levels. The associations among AMI admissions, the included pollutants, temperature, and relative humidity were analyzed using correlation and logistic regression. Results The urban background levels of PM2.5, PM10 and CO were associated with an increased risk of AMI, unlike NO2 and SO2 levels. The OR （95% CI） for AMI were 1.16 （1.03-1.29）, 1.05 （1.01-1.16）, 0.82 （0.75-1.02）, 0.87 （0.63-1.95）, and 1.08 （1.02-1.21） for PM2.5, PM10, NO2, SO2, and CO, respectively. Increases in the air quality index （AQI） were associated with more AMI occurrences. There was no correlation between fluctuations in temperature and relative humidity with AMI hospital admissions. Conclusions Short-term exposure to moderate-serious pollution levels is associated with increased risk of AMI. Increased PM2.5, PM10 and CO levels are related to increased AMI admissions.展开更多
In this paper the generalized equations for spinning space are investigated and the constants of motion are derived in terms of the solutions of these equations. We study the geodesic motion of the pseudo-classical sp...In this paper the generalized equations for spinning space are investigated and the constants of motion are derived in terms of the solutions of these equations. We study the geodesic motion of the pseudo-classical spinning particles in the spacetime produced by an idealized cosmic string and the non-extreme stationary axisymmetric black hole spacetime. The bound state orbits in a plane are discussed. We also show, for a conical spacetime and the Kerr spacetime, that the geodesic motion of spinning particles is different.展开更多
This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquake...This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquakes occurring along the Tancheng-Lujiang fault zone and its bilateral areas in Shandong,Liaoning,Hebei,Jiangsu and Jiangxi Provinces in the period from 1966 to 2005. Results show that:( 1) For M7. 0 and M6. 0earthquakes,med-term abnormities are the greatest in number,short-term abnormities come second,and imminent anomalies are the least. For M5. 0 earthquakes,short-term abnormities are often the most in number,imminent anomalies come second,and the med-term ones are the least.( 2) Precursory anomalies are periodical,part of the med and short-term anomalies are shown as short-term and imminent anomalies during their development.( 3) The development of precursor shows quasi-synchronism; the closer to earthquake occurrence time,the more turning changes of anomalies will appear.( 4)Anomalies mainly occur within an epicenter distance of 100 km, showing a relative concentrated distribution in space,and the shorter the distance to epicenter,the higher the anomaly station / item rate.( 5) The spatial distribution of anomalies is relatively correlated to the strike of structures,having a good consistency with the structure.( 6)There is no significant correlation between duration of abnormities and the epicenter distance.( 7) The higher the magnitude of the earthquake,the greater the amplitude of the abnormities measured with the same observation approach.( 8) In terms of the itemsof the observations,fluid abnormities are the greatest in number,followed by deformation and electromagnetism observations.( 9) For all observation items,med and short-term abnormities make up the majority and short-term and imminent anomalies the minority.( 10) In fluid,deformation and electromagnetism observations,fairly reliable anomalies are about double the number of reliable anomalies.展开更多
Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in steppe region in Inner Mongolia, China is urgently needed. An intensive investigation of the temporal va...Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in steppe region in Inner Mongolia, China is urgently needed. An intensive investigation of the temporal varia-tions of δD and δ^18O in precipitation was conducted in 2007-2008 in the Xilin River Basin, Inner Mongolia in the northern China. The 6D and δ^18O values for 54 precipitation samples range from ＋1.1%o to -34.7%0 and -3.0%0 to -269%0, respectively. This wide range indicates that stable isotopes in precipitation are primarily controlled by differ-ent condensation mechanisms as a function of air temperature and varying sources of vapor. The relationship between δD and δ^18O defined a well constrained line given by δD = 7.896180 ＋ 9.5, which is nearly identical to the Meteoric Water Line in the northern China. The temperature effect is clearly displayed in this area. The results of backward tra-jectory of each precipitation day show that the vapor of the precipitation in cold season （October to March） mainly originates from the west while the moisture source is more complicated in warm season （April to September）. A light precipitation amount effect existes at the precipitation event scale in this area. The vapor source of precipitation with higher d-excesses are mainly from the west wind or neighboring inland area and precipitation with lower d-excesses from a monsoon source from the southeastern China.展开更多
This study aims to investigate the effect of the continuation task （CT） on the acquisition of the Chinese spatial phrase structure （SPS） by learners of various L1 backgrounds learning Chinese as a second language ...This study aims to investigate the effect of the continuation task （CT） on the acquisition of the Chinese spatial phrase structure （SPS） by learners of various L1 backgrounds learning Chinese as a second language （CSL）. Two groups of participants were formed： a continuation group and a reading comprehension group. The former was required to continue in Chinese a text with its ending removed, while the latter needed to complete the Q＆A questions after reading the same text. The effect of the tasks was measured by examining the CSL learners＇ correct use of the Chinese SPS in three aspects -- the circum-construction, the use of prepositions and the use of the locative. The study found that the continuation group made significant improvement from the pretest to the posttests while the reading comprehension group did not. Moreover, the continuation group outperformed the reading comprehension group significantly in the posttests, though there was no significant difference between them in the pretest. The results showed that CT can facilitate CSL learners＇ acquisition of the Chinese SPS, with a better effect than the reading comprehension task.展开更多
The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can sup...The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can suppress the air-side heat transfer enhancement to a great extent. It has been proved that the serrated fins can enhance heat transfer obviously by breaking the development of boundary layer periodically. In the present study,the discontinuous short wave fin was introduced to the flat tube to enhance the air-side heat transfer of ACC. Two different types of arrangements,i.e. staggered and in-line for discontinuous short wave fins on the flat tube,were designed. By numerical simulation,the heat transfer and flow performances of short wave fins were studied under different arrangements(in-line,staggered) ,and the influences on heat transfer and flow characteristics of rows of short wave fin and interrupted distance between discontinuous short wave fins were revealed numerically. The results indicated that,compared with the original continuous wave fin,the discontinuous short wave fin effectively improved the air-side heat transfer of flat tube under the air flow velocities in the practical application of engineering. Moreover,the increment of pressure loss of air-side flow was restricted for the discontinuous short wave fins because of the reduction of contact areas between the air flow and fin surface.展开更多
This paper studies the multi-objective optimization of space station short-term mission planning(STMP), which aims to obtain a mission-execution plan satisfying multiple planning demands. The planning needs to allocat...This paper studies the multi-objective optimization of space station short-term mission planning(STMP), which aims to obtain a mission-execution plan satisfying multiple planning demands. The planning needs to allocate the execution time effectively, schedule the on-board astronauts properly, and arrange the devices reasonably. The STMP concept models for problem definitions and descriptions are presented, and then an STMP multi-objective planning model is developed. To optimize the STMP problem, a Non-dominated Sorting Genetic Algorithm II(NSGA-II) is adopted and then improved by incorporating an iterative conflict-repair strategy based on domain knowledge. The proposed approach is demonstrated by using a test case with thirty-five missions, eighteen devices and three astronauts. The results show that the established STMP model is effective, and the improved NSGA-II can successfully obtain the multi-objective optimal plans satisfying all constraints considered. Moreover, through contrast tests on solving the STMP problem, the NSGA-II shows a very competitive performance with respect to the Strength Pareto Evolutionary Algorithm II(SPEA-II) and the Multi-objective Particle Swarm Optimization(MOPSO).展开更多
Objective:To evaluate the effects of the modified Linggui Zhugan Decoction(加味苓桂术甘汤) combined with short-term very low calorie diets(VLCDs) on glycemic control in newly diagnosed type 2 diabetes mellitus(T2DM) p...Objective:To evaluate the effects of the modified Linggui Zhugan Decoction(加味苓桂术甘汤) combined with short-term very low calorie diets(VLCDs) on glycemic control in newly diagnosed type 2 diabetes mellitus(T2DM) patients.Methods:A total of 20 subjects with newly diagnosed T2DM were treated with the modified Linggui Zhugan Decoction(one-month administration) combined with short-term VLCDs(5 days),and 3-months follow-up.A standard 75-g oral-glucose-tolerance test(OGTT) indexes fasting plasma glucose(FPG),post-prandial 0.5 h and 2 h plasma glucose(P0.5hPG,P2hPG),glycated hemoglobin A1C(GHbA1C),body weight,body mass index(BMI),insulin function,insulin resistance index,incidence of hypoglycemia,and the liver and renal functions were evaluated before and after treatment.Correlations of BMI with insulin function and insulin resistance were also assessed.Results:After the treatment,the patients' plasma glucose decreased steadily,FPG decreased from 5.8±0.9 mmol/L at pre-treatment to 5.0±0.6 mmol/L at 3-months follow-up(P<0.05),and P2hPG decreased from 11.7±3.8 mmol/L at pre-treatment to 6.9±0.9 mmol/L at 3-months follow-up(P<0.01).The level of GHbA1C declined from(6.47±1.24)% at pre-treatment to(6.14±0.99)% at 3-months follow-up(P<0.01).Body weight and BMI also declined significantly.Insulin resistance index was improved obviously and no event of hypoglycemia occurred.Part of the patients companied with fatty liver had a transient increase in hepatic transaminase during the treatment,but it turned to normal after the treatment.Conclusions:The modified Linggui Zhugan Decoction combined with short-term VLCDs can be safely implemented for steady glycemic control in newly diagnosed T2DM patients.展开更多
Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyr...Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole （DPP） terminals, of which the derived organic solar cells （OSCs） exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor （A-D-A） SMs can significantly alter the resultant short-circuit current density and power conversion efficiency （PCE） in OSCs. The Pyr（EH-DPP）2 with short side chains displays broader absorption and higher hole mobility than the Pyr（HD-DPP）2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA（EH-DPP）2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr（EH-DPP）2 is several times higher than those based on Pyr（HD-DPP）： and PyrA（EH-DPP）2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.展开更多
基金Supported by a grant from the National Natural Science Foundation of China （No. 30600592）.
文摘Objective： To construct a lentiviral expression vector for RNA interference （RNAi） of human VIM gene; and assess its gene silencing effect in pancreatic cancer cell line Panc-1. Methods： Three pairs of human VIM gene short hairpin RNA（shRNA） sequences were designed using a software available on-line and one pair came from document. After synthesis and annealing, four double-stranded oligonucleotides （dsOligo） were cloned into the pGCL-GFP/U6 plasmid, which were subsequently confirmed by polymerase chain reaction （PCR） and DNA sequencing analysis. Real-time PCR and Westemblotting were used to screen the effective pGCL-GFP-shRNA plasmid in 293T cells, then the most effective one was packed into the recombinant lentivirus Lv-VIM-shRNA with lentiviral packing materials pHelper 1.0 and pHelper 2.0 in 293T cells. The titer of lentivirus was determined by hole-by-dilution titer assay. The silencing effect of Lv-VIM-shRNA in Panc-1 calls were validated by real-time PCR and Western-blotting. Results： An effective Lv-VIM-shRNA was successfully constructed. The titer of lentivirus was determined on 2× 10^9TU/mL. The expressions of VIM mRNA and vimentin were down-regluated in the Panc-1 cells infected with Lv-VIM-shRNA. Conclusion： An effective Lv-VIM-shRNA could inhibit the expression of VIM gene in Panc-1 cells in vitro, which provides a tool for investigating the role of VIM gene in the signaling pathway involved in tumorigenesis and progression of pancreatic cancer and searching new therapeutic targets.
基金funded by National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2012BAC23B01)National Natural Science Foundation of China(Grant Nos.41271098,41171066)China Special Fund for Meteorological Research in the Public Interest(GYHY201206026)
文摘Forest canopy reduces shortwave radiation and increases the incoming longwave radiation to snowpacks beneath forest canopies. Furthermore, the effect of forest canopy may be changed by complex topography. In this paper, we measured and simulated the incoming longwave radiation to snow beneath forest at different canopy openness in the west Tianshan Mountains, China(43°16'N, 84°24'E) during spring 2013. A sensitivity study was conducted to explore the way that terrain influenced the incoming longwave radiation to snow beneath forest canopies. In the simulation model, measurement datasets, including air temperature, incoming shortwave radiation above canopy, and longwave radiation enhanced by adjacent terrain, were applied to calculate the incoming longwave radiation to snow beneath forest canopy. The simulation results were consistent with the measurements on hourly scale and daily scale. The effect of longwave radiation enhanced by terrain was important than that of shortwave radiation above forest canopy with different openness except the 20% canopy openness. The longwave radiation enhanced due to adjacent terrain increases with the slope increase and temperature rise. When air temperature(or slope) is relatively low, thelongwave radiation enhanced by adjacent terrain is not sensitive to slope(or air temperature), but the sensitivity increases with the decrease of snow cover area on sunny slope. The effect of longwave radiation is especially sensitive when the snow cover on sunny slope melts completely. The effect of incoming shortwave radiation reflected by adjacent terrain on incoming longwave radiation to snow beneath forest canopies is more slight than that of the enhanced longwave radiation.
文摘Background Although particulate matter, with diameters 〈 2.5 μm （PM2.5） and 〈 10 μm （PM10）, and other pollutants have been associated with cardiovascular morbidity and mortality, the effect of pollutants on acute myocardial infarctions （AMIs） has rarely been investigated in Asia, especially in Shanghai, China. Methods Between 1 November 2013 and 27 April 2014, 972 patients from the Pudong District, Shanghai City, were assessed by the Emergency Medical Service. A case-crossover design was used to analyze exposure to air pollution and the AMI risk. Exposures to PM2.5, PM10, nitrogen dioxide （NO2）, sulphurdioxide （SO2）, and carbon monoxide （CO） were based on the mean urban background levels. The associations among AMI admissions, the included pollutants, temperature, and relative humidity were analyzed using correlation and logistic regression. Results The urban background levels of PM2.5, PM10 and CO were associated with an increased risk of AMI, unlike NO2 and SO2 levels. The OR （95% CI） for AMI were 1.16 （1.03-1.29）, 1.05 （1.01-1.16）, 0.82 （0.75-1.02）, 0.87 （0.63-1.95）, and 1.08 （1.02-1.21） for PM2.5, PM10, NO2, SO2, and CO, respectively. Increases in the air quality index （AQI） were associated with more AMI occurrences. There was no correlation between fluctuations in temperature and relative humidity with AMI hospital admissions. Conclusions Short-term exposure to moderate-serious pollution levels is associated with increased risk of AMI. Increased PM2.5, PM10 and CO levels are related to increased AMI admissions.
基金＊The project supported by the National Basic Research Program of China under Grant No. 2003CB716300 and Natural Science Foundation of Hunan Educational Department under Grant Nos. 03A028 and 02C203
文摘In this paper the generalized equations for spinning space are investigated and the constants of motion are derived in terms of the solutions of these equations. We study the geodesic motion of the pseudo-classical spinning particles in the spacetime produced by an idealized cosmic string and the non-extreme stationary axisymmetric black hole spacetime. The bound state orbits in a plane are discussed. We also show, for a conical spacetime and the Kerr spacetime, that the geodesic motion of spinning particles is different.
基金supported financially by Science for Earthquake Resilience(XH14064Y)the open foundation of the State Key Laboratory of Geodesy and Earth's Dynamics(SKLGED2014-5-2-E)the major national science and technology support project(2012BAK19B04-05-02)
文摘This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquakes occurring along the Tancheng-Lujiang fault zone and its bilateral areas in Shandong,Liaoning,Hebei,Jiangsu and Jiangxi Provinces in the period from 1966 to 2005. Results show that:( 1) For M7. 0 and M6. 0earthquakes,med-term abnormities are the greatest in number,short-term abnormities come second,and imminent anomalies are the least. For M5. 0 earthquakes,short-term abnormities are often the most in number,imminent anomalies come second,and the med-term ones are the least.( 2) Precursory anomalies are periodical,part of the med and short-term anomalies are shown as short-term and imminent anomalies during their development.( 3) The development of precursor shows quasi-synchronism; the closer to earthquake occurrence time,the more turning changes of anomalies will appear.( 4)Anomalies mainly occur within an epicenter distance of 100 km, showing a relative concentrated distribution in space,and the shorter the distance to epicenter,the higher the anomaly station / item rate.( 5) The spatial distribution of anomalies is relatively correlated to the strike of structures,having a good consistency with the structure.( 6)There is no significant correlation between duration of abnormities and the epicenter distance.( 7) The higher the magnitude of the earthquake,the greater the amplitude of the abnormities measured with the same observation approach.( 8) In terms of the itemsof the observations,fluid abnormities are the greatest in number,followed by deformation and electromagnetism observations.( 9) For all observation items,med and short-term abnormities make up the majority and short-term and imminent anomalies the minority.( 10) In fluid,deformation and electromagnetism observations,fairly reliable anomalies are about double the number of reliable anomalies.
基金Under the auspices of Nation Basic Research Program of China(No.2007CB411502)German Science Foundation(Research Unit 536)Independent Research Project from State Key Laboratory of Cryospheric Science(No.SKLCS-ZZ-2010-02)
文摘Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in steppe region in Inner Mongolia, China is urgently needed. An intensive investigation of the temporal varia-tions of δD and δ^18O in precipitation was conducted in 2007-2008 in the Xilin River Basin, Inner Mongolia in the northern China. The 6D and δ^18O values for 54 precipitation samples range from ＋1.1%o to -34.7%0 and -3.0%0 to -269%0, respectively. This wide range indicates that stable isotopes in precipitation are primarily controlled by differ-ent condensation mechanisms as a function of air temperature and varying sources of vapor. The relationship between δD and δ^18O defined a well constrained line given by δD = 7.896180 ＋ 9.5, which is nearly identical to the Meteoric Water Line in the northern China. The temperature effect is clearly displayed in this area. The results of backward tra-jectory of each precipitation day show that the vapor of the precipitation in cold season （October to March） mainly originates from the west while the moisture source is more complicated in warm season （April to September）. A light precipitation amount effect existes at the precipitation event scale in this area. The vapor source of precipitation with higher d-excesses are mainly from the west wind or neighboring inland area and precipitation with lower d-excesses from a monsoon source from the southeastern China.
基金supported by a grant from the China National Social Science Foundation (14CYY018)~~
文摘This study aims to investigate the effect of the continuation task （CT） on the acquisition of the Chinese spatial phrase structure （SPS） by learners of various L1 backgrounds learning Chinese as a second language （CSL）. Two groups of participants were formed： a continuation group and a reading comprehension group. The former was required to continue in Chinese a text with its ending removed, while the latter needed to complete the Q＆A questions after reading the same text. The effect of the tasks was measured by examining the CSL learners＇ correct use of the Chinese SPS in three aspects -- the circum-construction, the use of prepositions and the use of the locative. The study found that the continuation group made significant improvement from the pretest to the posttests while the reading comprehension group did not. Moreover, the continuation group outperformed the reading comprehension group significantly in the posttests, though there was no significant difference between them in the pretest. The results showed that CT can facilitate CSL learners＇ acquisition of the Chinese SPS, with a better effect than the reading comprehension task.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No.2009CB219804)
文摘The typical configuration adopted by air-cooled condenser(ACC) in coal-fired power generating unit is the wave finned flat tube. The development of boundary layer between wave fins along long axis of flat tube can suppress the air-side heat transfer enhancement to a great extent. It has been proved that the serrated fins can enhance heat transfer obviously by breaking the development of boundary layer periodically. In the present study,the discontinuous short wave fin was introduced to the flat tube to enhance the air-side heat transfer of ACC. Two different types of arrangements,i.e. staggered and in-line for discontinuous short wave fins on the flat tube,were designed. By numerical simulation,the heat transfer and flow performances of short wave fins were studied under different arrangements(in-line,staggered) ,and the influences on heat transfer and flow characteristics of rows of short wave fin and interrupted distance between discontinuous short wave fins were revealed numerically. The results indicated that,compared with the original continuous wave fin,the discontinuous short wave fin effectively improved the air-side heat transfer of flat tube under the air flow velocities in the practical application of engineering. Moreover,the increment of pressure loss of air-side flow was restricted for the discontinuous short wave fins because of the reduction of contact areas between the air flow and fin surface.
基金supported by the National Natural Science Foundation of China(Grant No.11402295)the Science Project of National University of Defense Technology(Grant No.JC14-01-05)the Hunan Provincial Natural Science Foundation of China(Grant No.2015JJ3020)
文摘This paper studies the multi-objective optimization of space station short-term mission planning(STMP), which aims to obtain a mission-execution plan satisfying multiple planning demands. The planning needs to allocate the execution time effectively, schedule the on-board astronauts properly, and arrange the devices reasonably. The STMP concept models for problem definitions and descriptions are presented, and then an STMP multi-objective planning model is developed. To optimize the STMP problem, a Non-dominated Sorting Genetic Algorithm II(NSGA-II) is adopted and then improved by incorporating an iterative conflict-repair strategy based on domain knowledge. The proposed approach is demonstrated by using a test case with thirty-five missions, eighteen devices and three astronauts. The results show that the established STMP model is effective, and the improved NSGA-II can successfully obtain the multi-objective optimal plans satisfying all constraints considered. Moreover, through contrast tests on solving the STMP problem, the NSGA-II shows a very competitive performance with respect to the Strength Pareto Evolutionary Algorithm II(SPEA-II) and the Multi-objective Particle Swarm Optimization(MOPSO).
基金supported by International Science and Technology Cooperation Program of Guangdong Province (No. 2009B050700022)
文摘Objective:To evaluate the effects of the modified Linggui Zhugan Decoction(加味苓桂术甘汤) combined with short-term very low calorie diets(VLCDs) on glycemic control in newly diagnosed type 2 diabetes mellitus(T2DM) patients.Methods:A total of 20 subjects with newly diagnosed T2DM were treated with the modified Linggui Zhugan Decoction(one-month administration) combined with short-term VLCDs(5 days),and 3-months follow-up.A standard 75-g oral-glucose-tolerance test(OGTT) indexes fasting plasma glucose(FPG),post-prandial 0.5 h and 2 h plasma glucose(P0.5hPG,P2hPG),glycated hemoglobin A1C(GHbA1C),body weight,body mass index(BMI),insulin function,insulin resistance index,incidence of hypoglycemia,and the liver and renal functions were evaluated before and after treatment.Correlations of BMI with insulin function and insulin resistance were also assessed.Results:After the treatment,the patients' plasma glucose decreased steadily,FPG decreased from 5.8±0.9 mmol/L at pre-treatment to 5.0±0.6 mmol/L at 3-months follow-up(P<0.05),and P2hPG decreased from 11.7±3.8 mmol/L at pre-treatment to 6.9±0.9 mmol/L at 3-months follow-up(P<0.01).The level of GHbA1C declined from(6.47±1.24)% at pre-treatment to(6.14±0.99)% at 3-months follow-up(P<0.01).Body weight and BMI also declined significantly.Insulin resistance index was improved obviously and no event of hypoglycemia occurred.Part of the patients companied with fatty liver had a transient increase in hepatic transaminase during the treatment,but it turned to normal after the treatment.Conclusions:The modified Linggui Zhugan Decoction combined with short-term VLCDs can be safely implemented for steady glycemic control in newly diagnosed T2DM patients.
基金supported by the National Natural Science Foundation of China(51473142,21674093,21374075)the Major State Basic Research Development Program(2014CB643503)International Science and Technology Cooperation Program of China(2016YFE0102900)
文摘Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole （DPP） terminals, of which the derived organic solar cells （OSCs） exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor （A-D-A） SMs can significantly alter the resultant short-circuit current density and power conversion efficiency （PCE） in OSCs. The Pyr（EH-DPP）2 with short side chains displays broader absorption and higher hole mobility than the Pyr（HD-DPP）2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA（EH-DPP）2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr（EH-DPP）2 is several times higher than those based on Pyr（HD-DPP）： and PyrA（EH-DPP）2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.
