This study was conducted to evaluate the water application uniformity for a drip irrigation system, considering the water quality and the duration of usage. The uniformity parameters, Emission Uniformity (EU %) and Un...This study was conducted to evaluate the water application uniformity for a drip irrigation system, considering the water quality and the duration of usage. The uniformity parameters, Emission Uniformity (EU %) and Uniformity Coefficient (UC %) were determined for the drip irrigation system </span><span style="font-family:Verdana;">installed over a year of performance. The procedures are based on taking</span><span style="font-family:Verdana;"> measurements of emitter discharge along selected driplines on a sub-main. The catch can </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">be</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> identified as L1A, L1B, L1C, L1D, same for L2A to L2D, L3A to L3D and L4A to L4D. This gave a total of sixteen (16) measurement positions as there were 4 driplines. Results indicated that the uniformity of water application was 90% indicating that the emitter was still good after a year of installation. The average discharge rate was 0.57</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">l/h. The uniformity coefficient (UC %) for the gravity-fed drip irrigation system was 78%, indicating good water application and was quite significant for the evaluation of the uniform distribution of water for the design. The expansion of this irrigation method in rural communities could contribute to relevant water savings in most areas of the Upper West Region of Ghana.展开更多
The temperature-dependent effect of residual charge carrier （no）, at the Dirac point, on mobility is studied. We fabricate and characterize a graphene field effect transistor （GFET） using 7nm TiO2 as the top-gate ...The temperature-dependent effect of residual charge carrier （no）, at the Dirac point, on mobility is studied. We fabricate and characterize a graphene field effect transistor （GFET） using 7nm TiO2 as the top-gate dielectric. The temperature-dependent gate voltage-drain current and room temperature gate capacitance are measured to extract the carrier mobility and to estimate the quantum capacitance of the GFET. The device shows the mobility value of gOO cm^2 /V.s at room temperature and it decreases to 45 cm^2 /V.s for 20 K due to the increase of n0. These results indicate that the phonon scattering is not the dominant process for the unevenness dielectric layer while the coulomb scattering by charged impurities degrades the device characteristically at low temperature.展开更多
We report on the temperature-dependent dc performance of A1GaN/GaN polarization doped field effect transistors （PolFETs）. The rough decrements of drain current and transeonductance with the operation temperature are...We report on the temperature-dependent dc performance of A1GaN/GaN polarization doped field effect transistors （PolFETs）. The rough decrements of drain current and transeonductance with the operation temperature are observed. Compared with the conventional HFETs, the drain current drop of the PolFET is smaller. The transeonductance drop of PolFETs at different gate biases shows different temperature dependences. From the aspect of the unique carrier behaviors of graded AlGaN/GaN heterostructure, we propose a quasi-multi-channel model to investigate the physics behind the temperature-dependent performance of AlGaN/GaN PolFETs.展开更多
Uniform seed spacing is considered a fundamental factor in quality and yield for many crops and drill manufacturers continuously try to improve the accuracy in seed placement, according to the cultivation standard req...Uniform seed spacing is considered a fundamental factor in quality and yield for many crops and drill manufacturers continuously try to improve the accuracy in seed placement, according to the cultivation standard requirements. This paper reports the results of tests on the performances of a six row pneumatic precision drill in which the depression into each sowing unit is created by means of flexible pipes that do not start directly from the fan, as in most pneumatic drills, but from an air duct having the function of uniformly distributing the air flow along the working width. Field tests have been conducted, using three graded seeds, to evaluate the accuracy of the single seed metering system, according to ISO 7256/1 standard, and the uniformity of negative pressure, through the measurement of the distance between seeds in the furrow, under two speed conditions （5 and 8 km bl）.展开更多
A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but als...A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan ispractically measured, and results compared with that from calculation. It shows that the process isexpected to be used in predicting performances of fluid machinery.展开更多
The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry....The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry.Pulsed laser deposition(PLD)has been extensively applied for fabrication of heteroepitaxial HTS wires or tapes based on REBCO-type superconductor,also referred to as,coated conductors(CCs).A combination of multi-plume,multi-turn deposition technique and use of high-power excimer lasers has enabled and accelerated the industrialization of REBCO coated conductors.Currently,the annual production of top-tier PLD-based,HTS-wire manufacturers exceeds 3,000 km-12 mm,contributing to over half of the total global HTS wire production.PLD-REBCO tapes have demonstrated excellent in-field performance(I_(c)>200 A-4 mm@20K,20T,B//c)and competitive pricing(∼$20/m).PLD technology continues to evolve,demonstrating strong competitive advantages.However,challenges remain in further cost reduction,process stability,and increasing efficiency of raw material utilization.AI-based data mining and tackling emerging fundamental issues are seen as potential solutions to further improve stability and performance.展开更多
A highrise tower atop short columns in Nantong,China was threatened by excavation of a subway station nearby.Although an elaborate protection plan composed of isolation piles,artificial recharge and underpinning was e...A highrise tower atop short columns in Nantong,China was threatened by excavation of a subway station nearby.Although an elaborate protection plan composed of isolation piles,artificial recharge and underpinning was executed throughout the excavations,the tower underwent unacceptable settlements and notable inclinations.In combination of field measurements and numerical simulations,this paper investigates the tower’s responses to the adjacent excavations,examines the effects of adopted protection plans and explores potential effective protection plans.First,the responses of the tower and the effectiveness of the three implemented measures were examined,and the contributory factors triggering intolerable tower deformations were identified;then,the effects of primary protection parameters were quantified,including the length,stiffness and layout of isolation piles,the water level surrounding recharge wells after recharging and the depth and location of wells,and the length of underpinning piles.It reveals that the underpinning plan had the best protection effect,followed by isolation piles and recharging wells.Construction timing of protection measures and termination manners of recharging are two critical factors in restraining tower deformations.Moreover,underpinning the tower with 36-m long steel pipe piles solely before implementation of adjacent excavations could be another optimal protection scheme.展开更多
文摘This study was conducted to evaluate the water application uniformity for a drip irrigation system, considering the water quality and the duration of usage. The uniformity parameters, Emission Uniformity (EU %) and Uniformity Coefficient (UC %) were determined for the drip irrigation system </span><span style="font-family:Verdana;">installed over a year of performance. The procedures are based on taking</span><span style="font-family:Verdana;"> measurements of emitter discharge along selected driplines on a sub-main. The catch can </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">be</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> identified as L1A, L1B, L1C, L1D, same for L2A to L2D, L3A to L3D and L4A to L4D. This gave a total of sixteen (16) measurement positions as there were 4 driplines. Results indicated that the uniformity of water application was 90% indicating that the emitter was still good after a year of installation. The average discharge rate was 0.57</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">l/h. The uniformity coefficient (UC %) for the gravity-fed drip irrigation system was 78%, indicating good water application and was quite significant for the evaluation of the uniform distribution of water for the design. The expansion of this irrigation method in rural communities could contribute to relevant water savings in most areas of the Upper West Region of Ghana.
文摘The temperature-dependent effect of residual charge carrier （no）, at the Dirac point, on mobility is studied. We fabricate and characterize a graphene field effect transistor （GFET） using 7nm TiO2 as the top-gate dielectric. The temperature-dependent gate voltage-drain current and room temperature gate capacitance are measured to extract the carrier mobility and to estimate the quantum capacitance of the GFET. The device shows the mobility value of gOO cm^2 /V.s at room temperature and it decreases to 45 cm^2 /V.s for 20 K due to the increase of n0. These results indicate that the phonon scattering is not the dominant process for the unevenness dielectric layer while the coulomb scattering by charged impurities degrades the device characteristically at low temperature.
文摘We report on the temperature-dependent dc performance of A1GaN/GaN polarization doped field effect transistors （PolFETs）. The rough decrements of drain current and transeonductance with the operation temperature are observed. Compared with the conventional HFETs, the drain current drop of the PolFET is smaller. The transeonductance drop of PolFETs at different gate biases shows different temperature dependences. From the aspect of the unique carrier behaviors of graded AlGaN/GaN heterostructure, we propose a quasi-multi-channel model to investigate the physics behind the temperature-dependent performance of AlGaN/GaN PolFETs.
文摘Uniform seed spacing is considered a fundamental factor in quality and yield for many crops and drill manufacturers continuously try to improve the accuracy in seed placement, according to the cultivation standard requirements. This paper reports the results of tests on the performances of a six row pneumatic precision drill in which the depression into each sowing unit is created by means of flexible pipes that do not start directly from the fan, as in most pneumatic drills, but from an air duct having the function of uniformly distributing the air flow along the working width. Field tests have been conducted, using three graded seeds, to evaluate the accuracy of the single seed metering system, according to ISO 7256/1 standard, and the uniformity of negative pressure, through the measurement of the distance between seeds in the furrow, under two speed conditions （5 and 8 km bl）.
文摘A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan ispractically measured, and results compared with that from calculation. It shows that the process isexpected to be used in predicting performances of fluid machinery.
基金support from the National Natural Science Foundation of China(Grant No.52277027)the Scientific Research Program of Science and Technology commission of Shanghai Municipality(Grant No.23511101500)+1 种基金financial supported from the China Postdoctoral Science Foundation(Grant No.2024M761969)Amit Goyal acknowledges financial support from Office of Naval Research(ONR),Grant No.N00014-21-1-2534.Hannu Huhtinen and Petriina Paturi acknowledge financial support from the Jenny and Antti Wihuri Foundation.
文摘The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry.Pulsed laser deposition(PLD)has been extensively applied for fabrication of heteroepitaxial HTS wires or tapes based on REBCO-type superconductor,also referred to as,coated conductors(CCs).A combination of multi-plume,multi-turn deposition technique and use of high-power excimer lasers has enabled and accelerated the industrialization of REBCO coated conductors.Currently,the annual production of top-tier PLD-based,HTS-wire manufacturers exceeds 3,000 km-12 mm,contributing to over half of the total global HTS wire production.PLD-REBCO tapes have demonstrated excellent in-field performance(I_(c)>200 A-4 mm@20K,20T,B//c)and competitive pricing(∼$20/m).PLD technology continues to evolve,demonstrating strong competitive advantages.However,challenges remain in further cost reduction,process stability,and increasing efficiency of raw material utilization.AI-based data mining and tackling emerging fundamental issues are seen as potential solutions to further improve stability and performance.
基金National Natural Science Foundation of China(Grant No.42177179).
文摘A highrise tower atop short columns in Nantong,China was threatened by excavation of a subway station nearby.Although an elaborate protection plan composed of isolation piles,artificial recharge and underpinning was executed throughout the excavations,the tower underwent unacceptable settlements and notable inclinations.In combination of field measurements and numerical simulations,this paper investigates the tower’s responses to the adjacent excavations,examines the effects of adopted protection plans and explores potential effective protection plans.First,the responses of the tower and the effectiveness of the three implemented measures were examined,and the contributory factors triggering intolerable tower deformations were identified;then,the effects of primary protection parameters were quantified,including the length,stiffness and layout of isolation piles,the water level surrounding recharge wells after recharging and the depth and location of wells,and the length of underpinning piles.It reveals that the underpinning plan had the best protection effect,followed by isolation piles and recharging wells.Construction timing of protection measures and termination manners of recharging are two critical factors in restraining tower deformations.Moreover,underpinning the tower with 36-m long steel pipe piles solely before implementation of adjacent excavations could be another optimal protection scheme.
