In this paper,a digital holography system with short-coherence light source is used to record a series of holograms of a micro-object.The three dimensional reconstruction is completed by the least-square-polynomial-fi...In this paper,a digital holography system with short-coherence light source is used to record a series of holograms of a micro-object.The three dimensional reconstruction is completed by the least-square-polynomial-fitting with a series of two dimensional intensity images which are obtained through holographic reconstruction.This three dimensional reconstruction method can be used to carry out three-dimensional reconstruction of a micro-object with strong laser speckle noise,which can not be obtained from the conventional method.展开更多
When wind appears over the free surface, water waves and turbulence are generated by an interfacial shear stress. In particular, turbulent diffusion promotes significantly mass and momentum transport beneath the inter...When wind appears over the free surface, water waves and turbulence are generated by an interfacial shear stress. In particular, turbulent diffusion promotes significantly mass and momentum transport beneath the interface between the water and air significantly in ocean and lakes, and thus it is very important for global environment problems to reveal such turbulence property and coherent structure. Simultaneous measurements of velocities and free-surface elevation allow us to conduct reasonably the phase analysis of the coherent structure in interfacial shear layer. Furthermore, multi-point measurements such as PIV are very powerful to detect the space-time structure of coherent motions. Therefore, in the present study, we developed a specially designed PIV system which can measure the velocity components and surface-elevation fluctuation simultaneously by using two sets of high-speed cameras to reveal the coherent structure in the interfacial shear layer.展开更多
The Milankovid theory stresses that the summer insolation in the high northern latitudes that is dominated by the precession cycle controls the glacial/interglacial cycles in global climate change. If the climate syst...The Milankovid theory stresses that the summer insolation in the high northern latitudes that is dominated by the precession cycle controls the glacial/interglacial cycles in global climate change. If the climate system responds linearly to the external insolation forcing, the precession cycle of 23 or 19 ka should dominate the variations in the climatic proxy records. I per- formed spectral and evolutive cross spectral analyses on the high resolution benthic ~80 and oa3C records from the South China Sea and the North Atlantic, the proxies of global ice volume and ocean carbon reservoir respectively. I found that the obliquity instead of the eccentricity or the precession is the most marked cycle in the global ice volume and ocean carbon res- ervoir variations over the past 5 Ma. The analysis further reveals that only at the obliquity band instead of the eccentricity or the precession band does the global ice volume and ocean carbon reservoir display consistently high coherency and stable phase relationship over the past 5 Ma. The consistently positive or near-zero phases of the benthic -o^SO relative to the benthic ff3C at the obliquity band suggest that the global carbon cycle is involved in the polar ice sheet growth as an important internal feedback, not a determinative driving factor. The obliquity instead of the precession or the eccentricity takes the dominant role of driving the global climate change during the Pliocene and Pleistocene.展开更多
We constructed a four-layer system composed of a prism,a silver film,an air layer and a lithium niobate crystal.Initially we used two coherent light beams to excite surface plasmons.The surface plasmons were then deco...We constructed a four-layer system composed of a prism,a silver film,an air layer and a lithium niobate crystal.Initially we used two coherent light beams to excite surface plasmons.The surface plasmons were then decoupled into light in the photorefractive crystal where a holographic grating was recorded.The two beams remained coherent through light to surface plasmons to light transformation.Studying the characteristics of the holographic grating we found out that the thickness of the grating was to the order of hundreds of microns.The thick holographic grating suggests that the holographic recording in the photorefractive materials was induced by the leaky waves rather than by surface plasmon polaritons directly.展开更多
The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the l...The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the light field intensity and the atomic motion on the field entropy are discussed. The results indicate that the motion of the atoms leads to strict periodicity in the field entropy evolution. When the two atoms are in the Bell state ｜β11〉 initially, the system is in a completely disentangled state. For the atoms initially at other Bell states, the field periodically entangles with the atoms.展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.60377008)the Natural Science Foundation of Tian-jin,China (Grant No.043800611)the State Key Laboratory of Modern Optical Instrumentations of Zhejiang University,China(Grant No.LMOI-0503)
文摘In this paper,a digital holography system with short-coherence light source is used to record a series of holograms of a micro-object.The three dimensional reconstruction is completed by the least-square-polynomial-fitting with a series of two dimensional intensity images which are obtained through holographic reconstruction.This three dimensional reconstruction method can be used to carry out three-dimensional reconstruction of a micro-object with strong laser speckle noise,which can not be obtained from the conventional method.
文摘When wind appears over the free surface, water waves and turbulence are generated by an interfacial shear stress. In particular, turbulent diffusion promotes significantly mass and momentum transport beneath the interface between the water and air significantly in ocean and lakes, and thus it is very important for global environment problems to reveal such turbulence property and coherent structure. Simultaneous measurements of velocities and free-surface elevation allow us to conduct reasonably the phase analysis of the coherent structure in interfacial shear layer. Furthermore, multi-point measurements such as PIV are very powerful to detect the space-time structure of coherent motions. Therefore, in the present study, we developed a specially designed PIV system which can measure the velocity components and surface-elevation fluctuation simultaneously by using two sets of high-speed cameras to reveal the coherent structure in the interfacial shear layer.
基金supported by the National Natural Science Foundation of China(Grant No.91128208)Shanghai Shuguang Program(Grant No.11SG24)+1 种基金New Century Excellent Talents in University(Grant No.NCET-08-0401)Shanghai Human Development Fund(Grant No.201336)
文摘The Milankovid theory stresses that the summer insolation in the high northern latitudes that is dominated by the precession cycle controls the glacial/interglacial cycles in global climate change. If the climate system responds linearly to the external insolation forcing, the precession cycle of 23 or 19 ka should dominate the variations in the climatic proxy records. I per- formed spectral and evolutive cross spectral analyses on the high resolution benthic ~80 and oa3C records from the South China Sea and the North Atlantic, the proxies of global ice volume and ocean carbon reservoir respectively. I found that the obliquity instead of the eccentricity or the precession is the most marked cycle in the global ice volume and ocean carbon res- ervoir variations over the past 5 Ma. The analysis further reveals that only at the obliquity band instead of the eccentricity or the precession band does the global ice volume and ocean carbon reservoir display consistently high coherency and stable phase relationship over the past 5 Ma. The consistently positive or near-zero phases of the benthic -o^SO relative to the benthic ff3C at the obliquity band suggest that the global carbon cycle is involved in the polar ice sheet growth as an important internal feedback, not a determinative driving factor. The obliquity instead of the precession or the eccentricity takes the dominant role of driving the global climate change during the Pliocene and Pleistocene.
基金supported by the National Basic Research Program of China (Grant Nos.2010CB934101 and 2012CB934201)the International S&T cooperation program of China (Grant No.2011DFA52870)+2 种基金the National Science Foundation of China (Grant Nos.11174161 and 11004112)Oversea Famous Teacher Project (Grant No.MS2010NKD-X023)the International cooperation program of Tianjin (Grant No.11ZCGHHZ01000)
文摘We constructed a four-layer system composed of a prism,a silver film,an air layer and a lithium niobate crystal.Initially we used two coherent light beams to excite surface plasmons.The surface plasmons were then decoupled into light in the photorefractive crystal where a holographic grating was recorded.The two beams remained coherent through light to surface plasmons to light transformation.Studying the characteristics of the holographic grating we found out that the thickness of the grating was to the order of hundreds of microns.The thick holographic grating suggests that the holographic recording in the photorefractive materials was induced by the leaky waves rather than by surface plasmon polaritons directly.
基金supported by the National Natural Science Foundation of Chinathe Nataral Science Foundation of Inner Mongolia of Chinathe Science Fund of Universiey in Inner Mongolia of China
文摘The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the light field intensity and the atomic motion on the field entropy are discussed. The results indicate that the motion of the atoms leads to strict periodicity in the field entropy evolution. When the two atoms are in the Bell state ｜β11〉 initially, the system is in a completely disentangled state. For the atoms initially at other Bell states, the field periodically entangles with the atoms.
