The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydro...The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydrologic properties of the environment;meaning effective porosity and transfer coefficient of springs. In general, in developed Karstic zones, each direct line of subsidence curve indicates a discharge regime. Obtained results from the study show that subsidence branch of Golestan, Motahari, Niloofar (changaei), Navekech, Dore Robat mirages have subsidence coefficient with mild slope and low value, which demonstrate passage of water through a seams system at the karst springs. Q and whirlpool stone mirages have two subsidence coefficients, which indicate passage of water through two seam systems in Karstic environment of springs. According to obtained results, process of changes in subsidence branch in these mirages has had at the first a mild slope and low discharge coefficient and in continue, its discharge would be declined with sharper slope and high discharge coefficient. In order to estimate dynamic storage volume of springs, MAILET general equation is applied, which is suitable for subsidence branch of hydrographs of centralized springs discharge. Following, dynamic storage volume of studied springs is analyzed and obtained results are presented in this study respectively.展开更多
To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase st...To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase structures and morphology of the experimental alloys were in vestigated by X-ray diffraction and transmission electron microscopy. The results show that increasing milling time and Ni content accelerate the formation of nanocrystalline and amorphous structure. The gaseous hydrogen storage properties of the experimental alloys were determined by differential scanning calorimetry （DSC） and Sievert apparatus. In addition, increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy, respectively. The enthalpy change （ △H ）, entropy change （△S） and the dehydrogenation activation energy （Exde） markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.展开更多
We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and th...We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and the cavities cannot be achieved instantly as soon as the two cavities are tuned into resonance,no matter the index tuning rate is ultrafast or slow.We also investigate the temporal evolution features of the intracavity energy when the pulse during time is prolonged.We find many periodical oscillations of the trapped energy in both cavities,and they are entirely complementary.Our analysis shows that the adiabatic wavelength conversion in both cavities and a phase difference π between them play critical roles in this phenomenon.展开更多
To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences...To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences of millingduration and Ni content on the electrochemical and gascous dynamics of the samples were studied in detail.Dehydrogena-tion activation cnergies of samples were calculated by using Kissinger and Arrhenius methods.The conclusions show thatthe dynamic properties of samples are significantly enhanced with the increase in Ni content.With the change of the miling duration,the gaseous hydrogenation rate and high rate discharging capability reach the maximal values.However,thedehydrogenation dynamics of sample alloys are always enhanced with the prolonging of milling duration.More concretely,prolonging milling duration from 5 to 60 h improves the dehydrogenation ratio of NdMgNi+100 wt.%Ni alloy from58.03%to 64.81%and that of NdMgNi+200 wt.%Ni alloy from 62.20%to 71.59%.Besides,the enhancement of gaseoushydrogen storage dynamics of the samples is believed to be the result of the declined dehydrogenation activation energyresulted from the increase in milling duration and Ni content.展开更多
The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball mill.The effects of metal sulfides on the hydrogenation and dehy...The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball mill.The effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were compared.The results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point defects.After ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)again.After hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after dehydrogenation.The maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,respectively.The hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 kJ.mol^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.展开更多
The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation wi...The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation with 0.5 wt.% Pd loading. The structural and oxygen handling properties were analyzed by X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and the dynamic oxygen storage capacity （DOSC）. The introduction of Co into ceria-zirconia lattice strongly modified the mobility of oxygen and enhanced the DOSC performance. Pd-only TWC based on the Co0.1Ce0.6Zr0.3Ox support exhibited superior activity for water-gas shift and steam reforming and ampli- fied amplitude of stoichiometric window.展开更多
FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen tempe...FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.展开更多
A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detaile...A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detailed physio-chemical characterizations were carried out to establish possible structure-activity correlations.Results show that on the one hand,different Pt/Pd ratios can strongly affect the TWC behaviors of Pt-Pd/CZL catalysts by modulating the synergistic effect between Pt and Pd.On the other hand,higher Pt/Pd ratio also favors better dispersion of precious metals.Such improved precious metals(PM)dispersion can promote the metal-support interaction and increase the surface oxygen vacancies concentration,thereby raising the dynamic oxygen storage/release capacity,improving the redox ability as well as enha ncing the thermal stability of the Pt-Pd/CZL catalyst.Moreover,the stro ng metal-support interaction can augment surface oxygen vacancy concentration,thereby benefiting low temperature CO and NO reaction via augmented NOxadsorption and nitrate conversion.展开更多
In the SSRF Phase-II beamline project, a superconducting wiggler（SW） will be installed in the electron storage ring. It may greatly impact on the beam dynamics due to the very high magnetic field. The emittance grow...In the SSRF Phase-II beamline project, a superconducting wiggler（SW） will be installed in the electron storage ring. It may greatly impact on the beam dynamics due to the very high magnetic field. The emittance growth becomes a major problem, even after correction of the beam optics. A local achromatic lattice is studied, in order to combat the emittance growth and keep the performance of the SSRF storage ring as high as possible. Other effects of the SW are also simulated and optimized, including the beta beating, the tune shift, the dynamic aperture, and the field error effects.展开更多
The fast-growing demand of computational fluid dynamics（CFD） application for computing resources stimulates the development of high performance computing（HPC） and meanwhile raises new requirements for the technolo...The fast-growing demand of computational fluid dynamics（CFD） application for computing resources stimulates the development of high performance computing（HPC） and meanwhile raises new requirements for the technology of parallel application performance monitor and analysis.In response to large-scale and long-time running for the application of CFD,online and scalable performance analysis technology is required to optimize the parallel programs as well as to improve their operational efficiency.As a result,this research implements a scalable infrastructure for online performance analysis on CFD application with homogeneous or heterogeneous system.The infrastructure is part of the parallel application performance monitor and analysis system（PAPMAS） and is composed of two modules which are scalable data transmission module and data storage module.The paper analyzes and elaborates this infrastructure in detail with respect to its design and implementation.Furthermore,some experiments are carried out to verify the rationality and high efficiency of this infrastructure that could be adopted to meet the practical needs.展开更多
The feasibility of rooftop rainwater harvesting （RRWH） as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems T...The feasibility of rooftop rainwater harvesting （RRWH） as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems Thinking, Experimental Learning Laboratory with Animation. The state of Arizona was selected to evaluate the effects of the selected model parameters on the efficacy of RRWH since among the nine states the arid region of Arizona showed the least potential of meeting the outdoor water demand with rain harvested water. The analyses were conducted on a monthly basis across a 10-year projected period from 2015 to 2024. The results showed that RRWH as a potential source of water was highly sensitive to certain model parameters such as the outdoor water demand, the use of desert landscaping, and the percentage of existing houses with RRWH. A significant difference （as high as 37.5%） in rainwater potential was observed between the projected wet and dry climate conditions in Arizona. The analysis of the dynamics of the storage tanks suggested that a 1.0-2.0 m3 rainwater barrel, on an average, can store approximately 80% of the monthly rainwater generated from the rooftops in Arizona, even across the high seasonal variation. This interactive model can be used as a quick estimator of the amount of water that could be generated, stored, and utilized through RRWH systems in the U.S. under different climate conditions. The findings of such comprehensive analyses may help regional policymakers, especially in arid regions, to develop a sustainable water management infrastructure.展开更多
Laser cooling of Li-like C^3＋and O^4＋relativistic heavy ion beams is planned at the experimental Cooler Storage Ring（CSRe）. Recently, a preparatory experiment to test important prerequisites for laser cooling of r...Laser cooling of Li-like C^3＋and O^4＋relativistic heavy ion beams is planned at the experimental Cooler Storage Ring（CSRe）. Recently, a preparatory experiment to test important prerequisites for laser cooling of relativistic^12C^3＋ion beams using a pulsed laser system has been performed at the CSRe. Unfortunately, the interaction between the ions and the pulsed laser cannot be detected. In order to study the laser cooling process and find the optimized parameters for future laser cooling experiments, a multi-particle tracking method has been developed to simulate the detailed longitudinal dynamics of laser-cooled ion beams at the CSRe. Simulations of laser cooling of the^12C^3＋ion beams by scanning the frequency of the RF-buncher or continuous wave（CW） laser wavelength have been performed. The simulation results indicate that ion beams with a large momentum spread could be laser-cooled by the combination of only one CW laser and the RF-buncher, and show the requirements of a successful laser cooling experiment. The optimized parameters for scanning the RF-buncher frequency or laser frequency have been obtained.Furthermore, the heating effects have been estimated for laser cooling at the CSRe. The Schottky noise spectra of longitudinally modulated and laser-cooled ion beams have been simulated to fully explain and anticipate the experimental results. The combination of Schottky spectra from the highly sensitive resonant Schottky pick-up and the simulation methods developed in this paper will be helpful to investigate the longitudinal dynamics of RF-bunched and ultra-cold ion beams in the upcoming laser cooling experiments at the CSRe.展开更多
文摘The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydrologic properties of the environment;meaning effective porosity and transfer coefficient of springs. In general, in developed Karstic zones, each direct line of subsidence curve indicates a discharge regime. Obtained results from the study show that subsidence branch of Golestan, Motahari, Niloofar (changaei), Navekech, Dore Robat mirages have subsidence coefficient with mild slope and low value, which demonstrate passage of water through a seams system at the karst springs. Q and whirlpool stone mirages have two subsidence coefficients, which indicate passage of water through two seam systems in Karstic environment of springs. According to obtained results, process of changes in subsidence branch in these mirages has had at the first a mild slope and low discharge coefficient and in continue, its discharge would be declined with sharper slope and high discharge coefficient. In order to estimate dynamic storage volume of springs, MAILET general equation is applied, which is suitable for subsidence branch of hydrographs of centralized springs discharge. Following, dynamic storage volume of studied springs is analyzed and obtained results are presented in this study respectively.
基金financially sponsored by National Natural Science Foundation of China (51471054)
文摘To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase structures and morphology of the experimental alloys were in vestigated by X-ray diffraction and transmission electron microscopy. The results show that increasing milling time and Ni content accelerate the formation of nanocrystalline and amorphous structure. The gaseous hydrogen storage properties of the experimental alloys were determined by differential scanning calorimetry （DSC） and Sievert apparatus. In addition, increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy, respectively. The enthalpy change （ △H ）, entropy change （△S） and the dehydrogenation activation energy （Exde） markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.
基金Project supported by the National Natural Science Foundation of China(Grant No.11774098)the Guangdong Natural Science Foundation(Grant Nos.2022A1515011950 and 2023A1515010781)the Science and Technology Program of Guangzhou(Grant No.202002030500)。
文摘We analytically and numerically investigate a signal light storing mechanism based on the controllable electromagnetically induced transparency(EIT)effect.We demonstrate that the isolation between the waveguide and the cavities cannot be achieved instantly as soon as the two cavities are tuned into resonance,no matter the index tuning rate is ultrafast or slow.We also investigate the temporal evolution features of the intracavity energy when the pulse during time is prolonged.We find many periodical oscillations of the trapped energy in both cavities,and they are entirely complementary.Our analysis shows that the adiabatic wavelength conversion in both cavities and a phase difference π between them play critical roles in this phenomenon.
基金It is sincere thanks to the National Natural Science Foundation of China(Nos.51871125 and 51761032)the MajorScience and Technology Innovation Projects in Shandong Province(2019JZZYO10320)for the financial support of this work.
文摘To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences of millingduration and Ni content on the electrochemical and gascous dynamics of the samples were studied in detail.Dehydrogena-tion activation cnergies of samples were calculated by using Kissinger and Arrhenius methods.The conclusions show thatthe dynamic properties of samples are significantly enhanced with the increase in Ni content.With the change of the miling duration,the gaseous hydrogenation rate and high rate discharging capability reach the maximal values.However,thedehydrogenation dynamics of sample alloys are always enhanced with the prolonging of milling duration.More concretely,prolonging milling duration from 5 to 60 h improves the dehydrogenation ratio of NdMgNi+100 wt.%Ni alloy from58.03%to 64.81%and that of NdMgNi+200 wt.%Ni alloy from 62.20%to 71.59%.Besides,the enhancement of gaseoushydrogen storage dynamics of the samples is believed to be the result of the declined dehydrogenation activation energyresulted from the increase in milling duration and Ni content.
基金the financial support provided by the Natural Science Foundations in Hebei Province(No.E2018201235)Baoding Science and Technology Planning Project(No.2074P019)+2 种基金Higher Education in Hebei Province School Science and Technology Research Project(No.QN2019209)Horizontal project(horizontal 20230048)2022 Hebei Province and Hebei University College Students Innovation and Entrepreneurship Training Program(Nos.2022265 and 2022266)。
文摘The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball mill.The effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were compared.The results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point defects.After ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)again.After hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after dehydrogenation.The maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,respectively.The hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 kJ.mol^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.
基金Project supported by National High-Tech Research and Development Program of China (2011AA03A405)the Key Program of Tianjin Natural Science Foundation (09JCZDJC26600)
文摘The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation with 0.5 wt.% Pd loading. The structural and oxygen handling properties were analyzed by X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and the dynamic oxygen storage capacity （DOSC）. The introduction of Co into ceria-zirconia lattice strongly modified the mobility of oxygen and enhanced the DOSC performance. Pd-only TWC based on the Co0.1Ce0.6Zr0.3Ox support exhibited superior activity for water-gas shift and steam reforming and ampli- fied amplitude of stoichiometric window.
基金This work was supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK20181310)the National Natural Science Foundation of China(Grant No.52079039).
基金support the National HighTech Research and Development Program of China (No.2011AA03A405)
文摘FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.
基金Project supported by the Key Program of Science Technology Department of Zhejiang Province(2018C03037)the Natural Science Foundation of Jiangsu Province(BK20201037)+2 种基金Jiangsu Industry-University-Research Cooperation Project(BY2022101)the Scientific Research Fund of Nanjing Institute of Technology(YKJ2019111)Students'Science and Technology Innovation Fund of Nanjing Institute of Technology(TB202312034).
文摘A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detailed physio-chemical characterizations were carried out to establish possible structure-activity correlations.Results show that on the one hand,different Pt/Pd ratios can strongly affect the TWC behaviors of Pt-Pd/CZL catalysts by modulating the synergistic effect between Pt and Pd.On the other hand,higher Pt/Pd ratio also favors better dispersion of precious metals.Such improved precious metals(PM)dispersion can promote the metal-support interaction and increase the surface oxygen vacancies concentration,thereby raising the dynamic oxygen storage/release capacity,improving the redox ability as well as enha ncing the thermal stability of the Pt-Pd/CZL catalyst.Moreover,the stro ng metal-support interaction can augment surface oxygen vacancy concentration,thereby benefiting low temperature CO and NO reaction via augmented NOxadsorption and nitrate conversion.
基金Supported by National Natural Science Foundation of China(11105214)
文摘In the SSRF Phase-II beamline project, a superconducting wiggler（SW） will be installed in the electron storage ring. It may greatly impact on the beam dynamics due to the very high magnetic field. The emittance growth becomes a major problem, even after correction of the beam optics. A local achromatic lattice is studied, in order to combat the emittance growth and keep the performance of the SSRF storage ring as high as possible. Other effects of the SW are also simulated and optimized, including the beta beating, the tune shift, the dynamic aperture, and the field error effects.
基金Aeronautical Science Foundation of China(2010ZA04001)National Natural Science Foundation of China (61073013,90818024)
文摘The fast-growing demand of computational fluid dynamics（CFD） application for computing resources stimulates the development of high performance computing（HPC） and meanwhile raises new requirements for the technology of parallel application performance monitor and analysis.In response to large-scale and long-time running for the application of CFD,online and scalable performance analysis technology is required to optimize the parallel programs as well as to improve their operational efficiency.As a result,this research implements a scalable infrastructure for online performance analysis on CFD application with homogeneous or heterogeneous system.The infrastructure is part of the parallel application performance monitor and analysis system（PAPMAS） and is composed of two modules which are scalable data transmission module and data storage module.The paper analyzes and elaborates this infrastructure in detail with respect to its design and implementation.Furthermore,some experiments are carried out to verify the rationality and high efficiency of this infrastructure that could be adopted to meet the practical needs.
文摘The feasibility of rooftop rainwater harvesting （RRWH） as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems Thinking, Experimental Learning Laboratory with Animation. The state of Arizona was selected to evaluate the effects of the selected model parameters on the efficacy of RRWH since among the nine states the arid region of Arizona showed the least potential of meeting the outdoor water demand with rain harvested water. The analyses were conducted on a monthly basis across a 10-year projected period from 2015 to 2024. The results showed that RRWH as a potential source of water was highly sensitive to certain model parameters such as the outdoor water demand, the use of desert landscaping, and the percentage of existing houses with RRWH. A significant difference （as high as 37.5%） in rainwater potential was observed between the projected wet and dry climate conditions in Arizona. The analysis of the dynamics of the storage tanks suggested that a 1.0-2.0 m3 rainwater barrel, on an average, can store approximately 80% of the monthly rainwater generated from the rooftops in Arizona, even across the high seasonal variation. This interactive model can be used as a quick estimator of the amount of water that could be generated, stored, and utilized through RRWH systems in the U.S. under different climate conditions. The findings of such comprehensive analyses may help regional policymakers, especially in arid regions, to develop a sustainable water management infrastructure.
基金Supported by National Natural Science Foundation of China(11405237,11504388)
文摘Laser cooling of Li-like C^3＋and O^4＋relativistic heavy ion beams is planned at the experimental Cooler Storage Ring（CSRe）. Recently, a preparatory experiment to test important prerequisites for laser cooling of relativistic^12C^3＋ion beams using a pulsed laser system has been performed at the CSRe. Unfortunately, the interaction between the ions and the pulsed laser cannot be detected. In order to study the laser cooling process and find the optimized parameters for future laser cooling experiments, a multi-particle tracking method has been developed to simulate the detailed longitudinal dynamics of laser-cooled ion beams at the CSRe. Simulations of laser cooling of the^12C^3＋ion beams by scanning the frequency of the RF-buncher or continuous wave（CW） laser wavelength have been performed. The simulation results indicate that ion beams with a large momentum spread could be laser-cooled by the combination of only one CW laser and the RF-buncher, and show the requirements of a successful laser cooling experiment. The optimized parameters for scanning the RF-buncher frequency or laser frequency have been obtained.Furthermore, the heating effects have been estimated for laser cooling at the CSRe. The Schottky noise spectra of longitudinally modulated and laser-cooled ion beams have been simulated to fully explain and anticipate the experimental results. The combination of Schottky spectra from the highly sensitive resonant Schottky pick-up and the simulation methods developed in this paper will be helpful to investigate the longitudinal dynamics of RF-bunched and ultra-cold ion beams in the upcoming laser cooling experiments at the CSRe.
