The stability of Bickley jet with particle laden flow is investigated numerically. The stability characteristics are calculated for various Stokes numbers and particle concentrations. The results confirm the author＇s...The stability of Bickley jet with particle laden flow is investigated numerically. The stability characteristics are calculated for various Stokes numbers and particle concentrations. The results confirm the author＇s early calculations, which also shows that the numerical program is reliable. It is further shown that there is a critical value for the effect of Stokes number, which is about 2. The most damped mode occurs when Stokes number is of order of 10 for different particle concentrations and depends weakly on the wave number. The difference in the eigenfunctions and its derivatives between the particle-laden flow and the clean gas flow is insignificant for fine particles, while the difference for coarse particles is significant.展开更多
The effect of inertial particles with different specific heat on heat transfer in particle-laden turbulent channel flows is studied using the direct numerical simulation（DNS） and the Lagrangian particle tracking met...The effect of inertial particles with different specific heat on heat transfer in particle-laden turbulent channel flows is studied using the direct numerical simulation（DNS） and the Lagrangian particle tracking method. The simulation uses a two-way coupling model to consider the momentum and thermal interactions between the particles and turbulence. The study shows that the temperature fields display differences between the particle-laden flow with different specific heat particles and the particle-free flow,indicating that the particle specific heat is an important factor that affects the heat transfer process in a particle-laden flow. It is found that the heat transfer capacity of the particle-laden flow gradually increases with the increase of the particle specific heat. This is due to the positive contribution of the particle increase to the heat transfer. In addition,the Nusselt number of a particle-laden flow is compared with that of a particle-free flow.It is found that particles with a large specific heat strengthen heat transfer of turbulent flow, while those with small specific heat weaken heat transfer of turbulent flow.展开更多
More than a decade has passed since the Soviet Union col-lapsed.The Cold War has ended,but history marches forward.The first chapter of post-Cold War history,laden with wars andstrifes,has just beguln.The narratives i...More than a decade has passed since the Soviet Union col-lapsed.The Cold War has ended,but history marches forward.The first chapter of post-Cold War history,laden with wars andstrifes,has just beguln.The narratives in the new chapter展开更多
Taiyuan seems at first glance to be yet another one of the typical smog-laden third-tier cities that dot northern China,but a glimpse of its history and temples reveals it was once the fulcrum for massive political an...Taiyuan seems at first glance to be yet another one of the typical smog-laden third-tier cities that dot northern China,but a glimpse of its history and temples reveals it was once the fulcrum for massive political and cultural展开更多
About five years ago,Liu Chun’er,a Beijingbased office professional,hated her own image in the mirror.＂Fat-laden waist and stocky legs obscured my curve,＂she said.She did not even have the courage to wear skirts.No...About five years ago,Liu Chun’er,a Beijingbased office professional,hated her own image in the mirror.＂Fat-laden waist and stocky legs obscured my curve,＂she said.She did not even have the courage to wear skirts.Now she loves to don skirts,snap pictures of herself and share them with her friends via social media platforms.展开更多
To investigate the influence of coherent structures in the gas-particle wake flow, direct numerical simulation (DNS) method was adopted to compute a two-dimensional particle laden wake flow. A high accuracy spectral e...To investigate the influence of coherent structures in the gas-particle wake flow, direct numerical simulation (DNS) method was adopted to compute a two-dimensional particle laden wake flow. A high accuracy spectral element method (SEM) was employed to simulate the gas flow field and a Lagrangian approach was used to compute the particles movement. Numerical results showed that at the same Stokes numbers, particles would be greatly impacted by the development of the coherent structure. But with different Stokes numbers, it can be seen that the large-scale vortex structures would influence the particle flow differently. While under different Reynolds numbers (150 and 200), there are no great changes in the particle laden flow.展开更多
Hamas is the Palestinian branch of the Global Muslim Brotherhood movement.Hamas emphasizes its nationalistic aspects and not just the Islamic ones.The Palestinian Abdullah Yusuf Azzam,Osama Bin Laden’s mentor,is the ...Hamas is the Palestinian branch of the Global Muslim Brotherhood movement.Hamas emphasizes its nationalistic aspects and not just the Islamic ones.The Palestinian Abdullah Yusuf Azzam,Osama Bin Laden’s mentor,is the link between the global jihad organizations and Hamas.Global jihad organizations like ISIS or al-Q'aida represent opposite points of view to those of the Muslim Brotherhood.First and foremost,they are not nationalistic but Pan-Islamic Movements.Islamic organizations cannot be described by ideas such as nationalism,socialism or any other set of secular ideas.Understanding Islamic organizations means understanding their religious roots.This article presents the argument that even Hamas,usually described as a nationalistic movement,can be identified as a Global Jihad organization which combines nationalistic elements.展开更多
Scientists[at Pennsylvania State University]found that a caterpillar called the tomato fruit worm not only chomps on tomatoes and their leaves,but also deposits enzyme-laden saliva on the plant,interfering with its ab...Scientists[at Pennsylvania State University]found that a caterpillar called the tomato fruit worm not only chomps on tomatoes and their leaves,but also deposits enzyme-laden saliva on the plant,interfering with its ability to cry for help.展开更多
当今美国人对本·拉登的的仇恨不言而喻。于是,有一个美国商人跑出来幽它一默:在卫生纸上印上了本·拉登的漫画。作者称此类幽默为dark humor。文章末尾的一句话,又让我们对这为商人肃然起敬,假如,他真的能兑现的话。文中出现了...当今美国人对本·拉登的的仇恨不言而喻。于是,有一个美国商人跑出来幽它一默:在卫生纸上印上了本·拉登的漫画。作者称此类幽默为dark humor。文章末尾的一句话,又让我们对这为商人肃然起敬,假如,他真的能兑现的话。文中出现了crack一词,其含义费思量。美国传统词典对它的释义之一是:to tell(a joke),especially on impulse or in an effective manner/开玩笑尤指机智并有效地说(笑话)展开更多
The purpose of this paper is to explore the origins,objectives,ideology,motivation,leadership structure,targets,strategies,tactics,and future of Al Qaeda.The past nearly two decades have seen the degrading,destruction...The purpose of this paper is to explore the origins,objectives,ideology,motivation,leadership structure,targets,strategies,tactics,and future of Al Qaeda.The past nearly two decades have seen the degrading,destruction,and dispersing of Al Qaeda across the Middle East and Africa but it still exists.Since 9/11 and the demise of Osama Bin Laden Al Qaeda has quietly worked at rebuilding itself across the globe using a franchising or licensing of affiliates across dozens of nations.So,it is essential that the study and analysis of this organization continue,so that it is finally destroyed and its ideas discredited and dismissed.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.50806023,50721005)the Program of Introducing Talents of Discipline to Universities,(111 Program,Grant No.B06019),China
文摘The stability of Bickley jet with particle laden flow is investigated numerically. The stability characteristics are calculated for various Stokes numbers and particle concentrations. The results confirm the author＇s early calculations, which also shows that the numerical program is reliable. It is further shown that there is a critical value for the effect of Stokes number, which is about 2. The most damped mode occurs when Stokes number is of order of 10 for different particle concentrations and depends weakly on the wave number. The difference in the eigenfunctions and its derivatives between the particle-laden flow and the clean gas flow is insignificant for fine particles, while the difference for coarse particles is significant.
基金Project supported by the National Natural Science Foundation of China(Nos.11272198 and11572183)
文摘The effect of inertial particles with different specific heat on heat transfer in particle-laden turbulent channel flows is studied using the direct numerical simulation（DNS） and the Lagrangian particle tracking method. The simulation uses a two-way coupling model to consider the momentum and thermal interactions between the particles and turbulence. The study shows that the temperature fields display differences between the particle-laden flow with different specific heat particles and the particle-free flow,indicating that the particle specific heat is an important factor that affects the heat transfer process in a particle-laden flow. It is found that the heat transfer capacity of the particle-laden flow gradually increases with the increase of the particle specific heat. This is due to the positive contribution of the particle increase to the heat transfer. In addition,the Nusselt number of a particle-laden flow is compared with that of a particle-free flow.It is found that particles with a large specific heat strengthen heat transfer of turbulent flow, while those with small specific heat weaken heat transfer of turbulent flow.
文摘More than a decade has passed since the Soviet Union col-lapsed.The Cold War has ended,but history marches forward.The first chapter of post-Cold War history,laden with wars andstrifes,has just beguln.The narratives in the new chapter
文摘Taiyuan seems at first glance to be yet another one of the typical smog-laden third-tier cities that dot northern China,but a glimpse of its history and temples reveals it was once the fulcrum for massive political and cultural
文摘About five years ago,Liu Chun’er,a Beijingbased office professional,hated her own image in the mirror.＂Fat-laden waist and stocky legs obscured my curve,＂she said.She did not even have the courage to wear skirts.Now she loves to don skirts,snap pictures of herself and share them with her friends via social media platforms.
文摘To investigate the influence of coherent structures in the gas-particle wake flow, direct numerical simulation (DNS) method was adopted to compute a two-dimensional particle laden wake flow. A high accuracy spectral element method (SEM) was employed to simulate the gas flow field and a Lagrangian approach was used to compute the particles movement. Numerical results showed that at the same Stokes numbers, particles would be greatly impacted by the development of the coherent structure. But with different Stokes numbers, it can be seen that the large-scale vortex structures would influence the particle flow differently. While under different Reynolds numbers (150 and 200), there are no great changes in the particle laden flow.
文摘Hamas is the Palestinian branch of the Global Muslim Brotherhood movement.Hamas emphasizes its nationalistic aspects and not just the Islamic ones.The Palestinian Abdullah Yusuf Azzam,Osama Bin Laden’s mentor,is the link between the global jihad organizations and Hamas.Global jihad organizations like ISIS or al-Q'aida represent opposite points of view to those of the Muslim Brotherhood.First and foremost,they are not nationalistic but Pan-Islamic Movements.Islamic organizations cannot be described by ideas such as nationalism,socialism or any other set of secular ideas.Understanding Islamic organizations means understanding their religious roots.This article presents the argument that even Hamas,usually described as a nationalistic movement,can be identified as a Global Jihad organization which combines nationalistic elements.
文摘Scientists[at Pennsylvania State University]found that a caterpillar called the tomato fruit worm not only chomps on tomatoes and their leaves,but also deposits enzyme-laden saliva on the plant,interfering with its ability to cry for help.
文摘当今美国人对本·拉登的的仇恨不言而喻。于是,有一个美国商人跑出来幽它一默:在卫生纸上印上了本·拉登的漫画。作者称此类幽默为dark humor。文章末尾的一句话,又让我们对这为商人肃然起敬,假如,他真的能兑现的话。文中出现了crack一词,其含义费思量。美国传统词典对它的释义之一是:to tell(a joke),especially on impulse or in an effective manner/开玩笑尤指机智并有效地说(笑话)
文摘The purpose of this paper is to explore the origins,objectives,ideology,motivation,leadership structure,targets,strategies,tactics,and future of Al Qaeda.The past nearly two decades have seen the degrading,destruction,and dispersing of Al Qaeda across the Middle East and Africa but it still exists.Since 9/11 and the demise of Osama Bin Laden Al Qaeda has quietly worked at rebuilding itself across the globe using a franchising or licensing of affiliates across dozens of nations.So,it is essential that the study and analysis of this organization continue,so that it is finally destroyed and its ideas discredited and dismissed.
