Using the numerical model of mixed convective-stratiform clouds(MCS)in the paper(Hong 1997)and the averaged stratification of torrential rain processes,the evolution processes, interaction of the two kinds of clouds,s...Using the numerical model of mixed convective-stratiform clouds(MCS)in the paper(Hong 1997)and the averaged stratification of torrential rain processes,the evolution processes, interaction of the two kinds of clouds,structure and the precipitation features in the MCS to produce heavy rain are simulated and studied,and the physical reasons of producing torrential rain are analysed.The results indicate that the stratiform cloud surrounding the convective cloud becomes weakened and dissipates in the developing and enhancing of the convective cloud,and the rainfall rate and water content in the stratiform cloud increase as the distance from the convective cloud becomes larger.The numerical experiments find out that the stratiform cloud provides a benificial developing environment for the convective cloud,i.e.,the saturated environment and the convergence field in the stratiform cloud help to lengthen the life cycle of the convective cloud, produce sustained rainfall with high intensity and intermittent precipitation with ultra-high intensity.These and the ice phase microphysical processes are the main factors for the torrential rain formation and the MCS is a very effective precipitation system.展开更多
In the Mexican Intertropical Convergence Zone, particle size distributions within 500 m of cloud boundaries at altitudes of 1000, 2500, and 4200 m, were compared against size distributions at the same levels but 1500 ...In the Mexican Intertropical Convergence Zone, particle size distributions within 500 m of cloud boundaries at altitudes of 1000, 2500, and 4200 m, were compared against size distributions at the same levels but 1500 m away from the clouds. The differences in the distributions near and far from the cloud are related to processes that may change particle properties inside the cloud. Chemical changes in the aerosols are deduced from the particles＇ refractive index, as derived from comparisons with the scattering coeflcient measured by a nephelometer. An analysis of ten cloud systems indicates that vertical transport of cloud base aerosol followed by entrainment/detrainment is the cloud processing signature most frequently observed in the comparisons （65%）. Changes in the chemical composition are observed in approximately 20% of the cases and another 20% of the cases showed removal by precipitation. About 5% of the comparisons showed clear evidence of changes by coalescence. The principal effect of these cloud-processed aerosols is observed in the increase of optical depth in the layer from 30 m to 4200 m in the near-cloud regions, in comparison with the atmosphere further from clouds.展开更多
A bow shock is formed in the interaction of a high-speed laser-driven plasma cloud with a cylinder obstacle. Its temporal and spatial structures are observed by shadowgraphy and interferometry. The width of the shock ...A bow shock is formed in the interaction of a high-speed laser-driven plasma cloud with a cylinder obstacle. Its temporal and spatial structures are observed by shadowgraphy and interferometry. The width of the shock transition region is - 50 μm, comparable to the ion–ion collision mean free path, which indicates that collision is dominated in the shock probably. The Mach-number of the ablating plasma cloud is ～ 15 at first, and decreases with time resulting in a changing shock structure. A two-dimension hydrodynamics code, USim, is used to simulate the interaction process. The simulated shocks can well reproduce the observed.展开更多
The Internet of thing（Io T） emerges as a possible solution to realize a smart life in the modern age. In this article, we design and realize a novel near field communication（NFC）-driven smart home system for Io T,...The Internet of thing（Io T） emerges as a possible solution to realize a smart life in the modern age. In this article, we design and realize a novel near field communication（NFC）-driven smart home system for Io T, which integrates the wireless sensor network（WSN）, social networks, and the cloud computing. NFC technology provides a way for users to exchange information between them and the system by simply contacting. So, we propose to use NFC as the system drive in the architecture, such that users can intuitively interact with the system and deliver their intentions. Then, the corresponding service over the system will control or adjust the “things” at home to fit users＇ needs. Furthermore, the proposed system provides a platform for developers to easily and rapidly implement their smart home related services. In the system, WSN sensing and control, NFC communications and identification, user profile management and preference analysis, and social network integration are all provided as platform services. We will show how the system works for home automation, intruder detection, and social network sharing.展开更多
This paper describes the latest progress of a collaborative research program entitled ＂Modeling Aerosol Climate Effects over Monsoon Asia＂, under the Climate Sciences agreement between the U.S. Department of Energy ...This paper describes the latest progress of a collaborative research program entitled ＂Modeling Aerosol Climate Effects over Monsoon Asia＂, under the Climate Sciences agreement between the U.S. Department of Energy and the Chinese Academy of Sciences（in the early 1980 s, Professor Duzheng YE played a critical role in leading and formalizing the agreement）. Here, the rationale and approach for pursuing the program, the participants, and research activities of recent years are first described, and then the highlights of the program＇s key findings and relevant scientific issues, as well as follow-up studies, are presented and discussed.展开更多
On April 27,2016,a striking true-color satellite image acquired by the Moderate Resolution Imaging Spectroradiometer（MODIS）onboard National Aeronautics and Space Administration’s（NASA’s）Aqua satellite showed sev...On April 27,2016,a striking true-color satellite image acquired by the Moderate Resolution Imaging Spectroradiometer（MODIS）onboard National Aeronautics and Space Administration’s（NASA’s）Aqua satellite showed several groups of very well structured arc cloud patterns（Fig.1）,which are associaed with atmospheric gravity waves,aligned in the middle of the Atlantic Ocean between展开更多
We review the long-term survival chances of young massive star clusters （YMCs）, hallmarks of intense starburst episodes often associated with Violent galaxy interactions. We address the key question as to whether at...We review the long-term survival chances of young massive star clusters （YMCs）, hallmarks of intense starburst episodes often associated with Violent galaxy interactions. We address the key question as to whether at least some of these YMCs can be considered protoglobular clusters （GCs）, in which case these would be expected to evolve into counterparts of the ubiquitous old GCs believed to be among the oldest galactic building blocks. In the absence of significant external perturbations, the key factor determining a cluster＇s long-term survival chances is the shape of its stellar initial mass function （IMF）. It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. We discuss in detail the promise of using high-resolution spectroscopy to make progress towards this goal, as well as the numerous pitfalls associated with this approach. We also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster systems, the disruption processes they are affected by, and whether we can use recently gained insights to determine the nature of at least some of the YMCs observed in extragalactic starbursts as proto-GCs. We conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however.展开更多
Natural aerosols provide large uncertainties regarding the quantification of the climate effects of aerosols,especially those related to aerosol-cloud interactions[1].Advancing research on the interaction of natural a...Natural aerosols provide large uncertainties regarding the quantification of the climate effects of aerosols,especially those related to aerosol-cloud interactions[1].Advancing research on the interaction of natural aerosols and climate can provide a better assessment of the climate impacts of anthropogenic activities.展开更多
文摘Using the numerical model of mixed convective-stratiform clouds(MCS)in the paper(Hong 1997)and the averaged stratification of torrential rain processes,the evolution processes, interaction of the two kinds of clouds,structure and the precipitation features in the MCS to produce heavy rain are simulated and studied,and the physical reasons of producing torrential rain are analysed.The results indicate that the stratiform cloud surrounding the convective cloud becomes weakened and dissipates in the developing and enhancing of the convective cloud,and the rainfall rate and water content in the stratiform cloud increase as the distance from the convective cloud becomes larger.The numerical experiments find out that the stratiform cloud provides a benificial developing environment for the convective cloud,i.e.,the saturated environment and the convergence field in the stratiform cloud help to lengthen the life cycle of the convective cloud, produce sustained rainfall with high intensity and intermittent precipitation with ultra-high intensity.These and the ice phase microphysical processes are the main factors for the torrential rain formation and the MCS is a very effective precipitation system.
文摘In the Mexican Intertropical Convergence Zone, particle size distributions within 500 m of cloud boundaries at altitudes of 1000, 2500, and 4200 m, were compared against size distributions at the same levels but 1500 m away from the clouds. The differences in the distributions near and far from the cloud are related to processes that may change particle properties inside the cloud. Chemical changes in the aerosols are deduced from the particles＇ refractive index, as derived from comparisons with the scattering coeflcient measured by a nephelometer. An analysis of ten cloud systems indicates that vertical transport of cloud base aerosol followed by entrainment/detrainment is the cloud processing signature most frequently observed in the comparisons （65%）. Changes in the chemical composition are observed in approximately 20% of the cases and another 20% of the cases showed removal by precipitation. About 5% of the comparisons showed clear evidence of changes by coalescence. The principal effect of these cloud-processed aerosols is observed in the increase of optical depth in the layer from 30 m to 4200 m in the near-cloud regions, in comparison with the atmosphere further from clouds.
基金Project supported by the National Basic Research Program of China(Grant No.2013CBA01501)the National Natural Science Foundation of China(Grant Nos.11135012,11375262,11503041,and 11520101003)the Science Challenge Program of China(Grant No.JCKY2016212A505)
文摘A bow shock is formed in the interaction of a high-speed laser-driven plasma cloud with a cylinder obstacle. Its temporal and spatial structures are observed by shadowgraphy and interferometry. The width of the shock transition region is - 50 μm, comparable to the ion–ion collision mean free path, which indicates that collision is dominated in the shock probably. The Mach-number of the ablating plasma cloud is ～ 15 at first, and decreases with time resulting in a changing shock structure. A two-dimension hydrodynamics code, USim, is used to simulate the interaction process. The simulated shocks can well reproduce the observed.
基金supported in part by the NSC under Grant No.103-2815-C-024-013-E and 102-2218-E-009-014-MY3the MOST under Grant No.103-2221-E-024-005
文摘The Internet of thing（Io T） emerges as a possible solution to realize a smart life in the modern age. In this article, we design and realize a novel near field communication（NFC）-driven smart home system for Io T, which integrates the wireless sensor network（WSN）, social networks, and the cloud computing. NFC technology provides a way for users to exchange information between them and the system by simply contacting. So, we propose to use NFC as the system drive in the architecture, such that users can intuitively interact with the system and deliver their intentions. Then, the corresponding service over the system will control or adjust the “things” at home to fit users＇ needs. Furthermore, the proposed system provides a platform for developers to easily and rapidly implement their smart home related services. In the system, WSN sensing and control, NFC communications and identification, user profile management and preference analysis, and social network integration are all provided as platform services. We will show how the system works for home automation, intruder detection, and social network sharing.
基金support by a grant from the Office of Sciences(BER),U.S.DOEsupport from the Key National Basic Research Program on Global Change(Grant No.2013CB955803)to facilitate the visits to Peking University and the Institute of Atmospheric Physics
文摘This paper describes the latest progress of a collaborative research program entitled ＂Modeling Aerosol Climate Effects over Monsoon Asia＂, under the Climate Sciences agreement between the U.S. Department of Energy and the Chinese Academy of Sciences（in the early 1980 s, Professor Duzheng YE played a critical role in leading and formalizing the agreement）. Here, the rationale and approach for pursuing the program, the participants, and research activities of recent years are first described, and then the highlights of the program＇s key findings and relevant scientific issues, as well as follow-up studies, are presented and discussed.
文摘On April 27,2016,a striking true-color satellite image acquired by the Moderate Resolution Imaging Spectroradiometer（MODIS）onboard National Aeronautics and Space Administration’s（NASA’s）Aqua satellite showed several groups of very well structured arc cloud patterns（Fig.1）,which are associaed with atmospheric gravity waves,aligned in the middle of the Atlantic Ocean between
文摘We review the long-term survival chances of young massive star clusters （YMCs）, hallmarks of intense starburst episodes often associated with Violent galaxy interactions. We address the key question as to whether at least some of these YMCs can be considered protoglobular clusters （GCs）, in which case these would be expected to evolve into counterparts of the ubiquitous old GCs believed to be among the oldest galactic building blocks. In the absence of significant external perturbations, the key factor determining a cluster＇s long-term survival chances is the shape of its stellar initial mass function （IMF）. It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. We discuss in detail the promise of using high-resolution spectroscopy to make progress towards this goal, as well as the numerous pitfalls associated with this approach. We also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster systems, the disruption processes they are affected by, and whether we can use recently gained insights to determine the nature of at least some of the YMCs observed in extragalactic starbursts as proto-GCs. We conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however.
基金supported by the National Key Research and Development Program of China(2024YFF0811400)the National Natural Science Foundation of China(42475032)+2 种基金Jiangsu Science Fund for Carbon Neutrality(BK20220031)Jiangsu Innovation Research Group(JSSCTD202346)The Pacific Northwest National Laboratory(PNNL)is operated for DOE by the Battelle Memorial Institute under contract DE-AC05-76RLO1830.
文摘Natural aerosols provide large uncertainties regarding the quantification of the climate effects of aerosols,especially those related to aerosol-cloud interactions[1].Advancing research on the interaction of natural aerosols and climate can provide a better assessment of the climate impacts of anthropogenic activities.
