Surface charge characteristics of a membrane can be determined by the streaming potential. In order to obtain more accurate streaming potential value during the measurement, four measurement operation modes were inves...Surface charge characteristics of a membrane can be determined by the streaming potential. In order to obtain more accurate streaming potential value during the measurement, four measurement operation modes were investigated in this study, and among the four modes, the steady mode with pressure stepped downward was considered the best one. Experimental results showed that the effects of compaction on the streaming potential measurement for a microfiltration membrane was more obvious than that for a ultrafiltration membrane. Both feed pH and presoaking could affect the measurement of streaming potential.展开更多
Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 ...Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.展开更多
We have studied the effects of the finite range on the fusion and/or breakup of ^6He^＋238U and ^11Li＋^208pb Pb dynamic polarization potential approach. It has been found of the interaction between the fragments of t...We have studied the effects of the finite range on the fusion and/or breakup of ^6He^＋238U and ^11Li＋^208pb Pb dynamic polarization potential approach. It has been found of the interaction between the fragments of the projectile systems at near barrier energies within the framework of that at near barrier energies the maximum flux is lost to the breakup channel and at energies well above the Coulomb barrier the fusion coupled with the breakup channel opens up, initially with sharp rise and later becoming saturated at energy nearly twice of the Coulomb barrier. Further, it is found that the breakup cross section increases with the increasing range of the interaction between the fragments of the projectile while the fusion coupled with the breakup channel cross section decreases with the increasing range.展开更多
Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpirat...Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.展开更多
We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can al...We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can allow the SBD to detect UV light irradiation with incident power of 6 × 10^-17 W （-85 photons/s on the NR） at room temperature, with excellent reproducibility and stability. The corresponding detectivity and photoconductive gain are calculated to be 3.1 × 10^20 cm.Hz1/2.W^-1 and 6.6 × 10^5, respectively. It is found that the presence of the trapping states at the p-ZnS NWITO interface plays a crucial role in determining the ultrahigh sensitivity of this nanoSBDs. Based on our theoretical calculation, even ultra-low photon fluxes on the order of several tens of photons could induce a significant change in interface potential and consequently cause a large photocurrent variation. The present study provides new opportunities for developiphigh-performance optoelectronic devices in the future.展开更多
基金the National Natural Science Foundation of China （No.29976031）, the Collaboration Project Foundation of Tianjin University and Nankal University, and the Key Project Foundation of Tianjin （No.0331810112）.
文摘Surface charge characteristics of a membrane can be determined by the streaming potential. In order to obtain more accurate streaming potential value during the measurement, four measurement operation modes were investigated in this study, and among the four modes, the steady mode with pressure stepped downward was considered the best one. Experimental results showed that the effects of compaction on the streaming potential measurement for a microfiltration membrane was more obvious than that for a ultrafiltration membrane. Both feed pH and presoaking could affect the measurement of streaming potential.
基金Under the auspices of National Natural Science Foundation of China (No. 40830535, 41001110, 41101092, 41171092)National Basic Research Program of China (No. 2010CB951304)the CAS/SAFEA (Chinese Academy of Sciences/State Administration of Foreign Experts Affairs) International Partnership Program for Creative Research Teams, Eleventh Five-Year' Key Technological Projects of Heilongjiang Province Farm Bureau (No. HNK10A-10-01, HNK10A-10-03)
文摘Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.
文摘We have studied the effects of the finite range on the fusion and/or breakup of ^6He^＋238U and ^11Li＋^208pb Pb dynamic polarization potential approach. It has been found of the interaction between the fragments of the projectile systems at near barrier energies within the framework of that at near barrier energies the maximum flux is lost to the breakup channel and at energies well above the Coulomb barrier the fusion coupled with the breakup channel opens up, initially with sharp rise and later becoming saturated at energy nearly twice of the Coulomb barrier. Further, it is found that the breakup cross section increases with the increasing range of the interaction between the fragments of the projectile while the fusion coupled with the breakup channel cross section decreases with the increasing range.
文摘Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.
文摘We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can allow the SBD to detect UV light irradiation with incident power of 6 × 10^-17 W （-85 photons/s on the NR） at room temperature, with excellent reproducibility and stability. The corresponding detectivity and photoconductive gain are calculated to be 3.1 × 10^20 cm.Hz1/2.W^-1 and 6.6 × 10^5, respectively. It is found that the presence of the trapping states at the p-ZnS NWITO interface plays a crucial role in determining the ultrahigh sensitivity of this nanoSBDs. Based on our theoretical calculation, even ultra-low photon fluxes on the order of several tens of photons could induce a significant change in interface potential and consequently cause a large photocurrent variation. The present study provides new opportunities for developiphigh-performance optoelectronic devices in the future.
