Non-classical polarization properties of dark hollow beams propagating through non-Kolmogorov turbulence are studied. The analytic equation for the polarization degree of the quantization partially coherent dark hollo...Non-classical polarization properties of dark hollow beams propagating through non-Kolmogorov turbulence are studied. The analytic equation for the polarization degree of the quantization partially coherent dark hollow beams is obtained.It is found that the polarization fluctuations of the quantization partially coherent dark hollow beams are dependent on the turbulence factors and beam parameters with the detection photon numbers. Furthermore, an investigation of the changes in the on-axis propagation point and off-axis propagation point shows that the polarization degree of the quantization partially coherent dark hollow beams presents oscillation for a short propagation distance and gradually returns to zero for a sufficiently long distance.展开更多
Diffraction-free vectorial elliptic hollow beams(vEHBs)are generated by an optical system composed of a short elliptic hollow fiber(EHF)and an axicon.Each beam has a closed elliptic annular intensity profile and space...Diffraction-free vectorial elliptic hollow beams(vEHBs)are generated by an optical system composed of a short elliptic hollow fiber(EHF)and an axicon.Each beam has a closed elliptic annular intensity profile and space-varying polarization states in its diffraction-free distance of more than 1 m.The generated beams have a counter-clockwise or clockwise periodically-rotated inhomogeneous polarization.And the spin angular momentum(SAM)of the vEHBs is 1ħor-1ħwhich is consistent with the type of dual-mode in the EHF and the periodic polarization rotations of the vEHBs.The vEHBs have potential applications in optically trapping and micromanipulating the micro-or nano-particles,quantum information transmission,and Bose-Einstein condensates,etc.展开更多
This paper reports that, based on the electromagnetic scattering theory of the multipole method, a high-quality hollow beam is produced through a selectively liquid-filled photonic crystal fibre. Instead of a doughnut...This paper reports that, based on the electromagnetic scattering theory of the multipole method, a high-quality hollow beam is produced through a selectively liquid-filled photonic crystal fibre. Instead of a doughnut shape, a typical hollow beam is produced by other methods; the mode-field images of the hollow-beam photonic crystal fibre satisfy sixth-order rotation symmetry, according to the symmetry of the photonic crystal fibre (PCF) structure. A dark spot size of the liquid-filled photonic crystal fibre-generated hollow beam can be tuned by inserting liquid into the cladding region and varying the photonic crystal fibre structure parameters. The liquid-filled PCF makes a convenient and flexible tool for the guiding and trapping of atoms and the creation of all-fibre optical tweezers.展开更多
Twelve ECC beams with three different fiber types,along with four normal concrete beams,were tested in this study to evaluate the influence of cross-sectional hollowing on their flexural performance.The fiber types us...Twelve ECC beams with three different fiber types,along with four normal concrete beams,were tested in this study to evaluate the influence of cross-sectional hollowing on their flexural performance.The fiber types used were nylon monofilament(NM),low-cost untreated polyvinyl alcohol(PVA),and polypropylene(PP).Three different square hole sizes of 60,80,and 100 mm with cross-sectional hollowing ratios of 0.16,0.28,and 0.44,respectively,were adopted for each group of beams in addition to a solid beam.All beams were tested under four-point loading using a displacement-controlled testing machine.The test results showed that ECC beams can mostly withstand higher cracking and ultimate loads compared to their corresponding normal concrete versions.The results also showed that both the ductility and toughness of the ECC beams are higher than those of the normal concrete beams and that the ductility values of the hollow beams with a hole size of 60 mm are higher than those of the corresponding solid beams.Moreover,hollow ECC beams with hole sizes of 60 and 80 mm exhibited a higher ductility than a solid normal concrete beam.展开更多
The far-field propagation properties of conical double half-Gaussian hollow beams in the condition of Collins formula are studied. Because of the cone angle of this kind of hollow beams, the diffraction is compensated...The far-field propagation properties of conical double half-Gaussian hollow beams in the condition of Collins formula are studied. Because of the cone angle of this kind of hollow beams, the diffraction is compensated and the inner diameter is turning bigger by the rule of geometric optics as the propagation distance is increasing, whereas the degenerating diffraction phenomenon is turned out. The far-field intensity distribution of the conical double half-Gaussian hollow beams in the condition of in-Collins formula is researched, and the results show that the far-field propagation properties can be depicted by this model. In the experiment, this kind of hollow beams are obtained by means of the dual-reflecting splitting optical system, and the inner diameter of the hollow beams is tested. The results show good agreement with the propagation theory in the condition of in-Collins formula.展开更多
A new kind of hollow beams, double half-Gaussian hollow beams,was put forward. With the help of the Collins formula, the analytical equation of propagation and transformation of the hollow laser beams in free space wa...A new kind of hollow beams, double half-Gaussian hollow beams,was put forward. With the help of the Collins formula, the analytical equation of propagation and transformation of the hollow laser beams in free space was deduced. The simulation shows that the intensity exhibits the three-dimensional trap distribution in the near-field, while the double half-Gaussian hollow beams turn into solid laser beams when propagating a certain distance, which shows the characteristics of self-focus. The double half-Gaussian hollow beams were obtained by means of the dual-reflecting splitting optical system. The intensity of the vertical loop in different distances was tested, which shows that the analytical equation of propagation and transformation is in agreement with the result.展开更多
The propagation of hollow Gaussian beams in strongly nonlocal nonlinear media is studied in detail. Two analytical expressions are derived. For hollow Gaussian beams, the intensity distribution always evolves periodic...The propagation of hollow Gaussian beams in strongly nonlocal nonlinear media is studied in detail. Two analytical expressions are derived. For hollow Gaussian beams, the intensity distribution always evolves periodically. However the second-order moment beam width can keep invariant during propagation if the input power is equal to the critical power. The interaction of two hollow Gaussian beams and the vortical hollow Gaussian beams are also discussed. The vortical hollow Gaussian beams with an appropriate topological charge can keep their shapes invariant during propagation.展开更多
The use of the sand concrete makes it possible to carry out a concrete having physico-mechanical properties answering the structural exigences and having economic and environmental advantages compared to the classical...The use of the sand concrete makes it possible to carry out a concrete having physico-mechanical properties answering the structural exigences and having economic and environmental advantages compared to the classical concrete. The present study aims to connecting the parameters of a formulation based on an empirical formula of Caquot in order to optimize, on the one hand the couple compressive strength/absorption of water under various degrees of hygrometry, and on the other hand more precisely to use the concrete sand in the public works sector in the prefabrication of prestressed beams and hollow bricks. The results show the importance of the type of formulation used because it takes into account the percentages of fillers of sand which is a co-product (waste) of massive rock crushing. In addition, the use of fillerized sands, which are wastes of crushing basaltic rocks and containing a small percentage of fillers, is efficient in the manufacture of prestressed beams. As for the hollow bricks, a fillerized basalt sand, containing a high percentage of filler, as well as a sand dune, gives satisfactory results.展开更多
In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic ana...In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.展开更多
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.61405205)
文摘Non-classical polarization properties of dark hollow beams propagating through non-Kolmogorov turbulence are studied. The analytic equation for the polarization degree of the quantization partially coherent dark hollow beams is obtained.It is found that the polarization fluctuations of the quantization partially coherent dark hollow beams are dependent on the turbulence factors and beam parameters with the detection photon numbers. Furthermore, an investigation of the changes in the on-axis propagation point and off-axis propagation point shows that the polarization degree of the quantization partially coherent dark hollow beams presents oscillation for a short propagation distance and gradually returns to zero for a sufficiently long distance.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304093 and 11274114)the Hubei Provincial Natural Science Foundation,China(Grant No.2018CFB320)the Academic Discipline Project of Hubei Normal University,China(Grant Nos.2014F012 and 2014F013).
文摘Diffraction-free vectorial elliptic hollow beams(vEHBs)are generated by an optical system composed of a short elliptic hollow fiber(EHF)and an axicon.Each beam has a closed elliptic annular intensity profile and space-varying polarization states in its diffraction-free distance of more than 1 m.The generated beams have a counter-clockwise or clockwise periodically-rotated inhomogeneous polarization.And the spin angular momentum(SAM)of the vEHBs is 1ħor-1ħwhich is consistent with the type of dual-mode in the EHF and the periodic polarization rotations of the vEHBs.The vEHBs have potential applications in optically trapping and micromanipulating the micro-or nano-particles,quantum information transmission,and Bose-Einstein condensates,etc.
基金Project supported in part by the National Natural Science Foundation of China(Grant No.10874145)the Specialized Research Fund for Doctorial Program of Higher Education(Grant No.20091333110010)+1 种基金the Natural Science Foundation of Heibei Province, China(Grant No.F2009000481)the China Postdoctoral Science Foundation(Grant Nos.20080440014 and 200902046)
文摘This paper reports that, based on the electromagnetic scattering theory of the multipole method, a high-quality hollow beam is produced through a selectively liquid-filled photonic crystal fibre. Instead of a doughnut shape, a typical hollow beam is produced by other methods; the mode-field images of the hollow-beam photonic crystal fibre satisfy sixth-order rotation symmetry, according to the symmetry of the photonic crystal fibre (PCF) structure. A dark spot size of the liquid-filled photonic crystal fibre-generated hollow beam can be tuned by inserting liquid into the cladding region and varying the photonic crystal fibre structure parameters. The liquid-filled PCF makes a convenient and flexible tool for the guiding and trapping of atoms and the creation of all-fibre optical tweezers.
基金This experimental study was conducted in the structural laboratory in the civil engineering department of Gaziantep University,Turkey.The authors would like to express their gratitude to the Department of Civil Engineering at Gaziantep University and the staff of the structural laboratory for their support.
文摘Twelve ECC beams with three different fiber types,along with four normal concrete beams,were tested in this study to evaluate the influence of cross-sectional hollowing on their flexural performance.The fiber types used were nylon monofilament(NM),low-cost untreated polyvinyl alcohol(PVA),and polypropylene(PP).Three different square hole sizes of 60,80,and 100 mm with cross-sectional hollowing ratios of 0.16,0.28,and 0.44,respectively,were adopted for each group of beams in addition to a solid beam.All beams were tested under four-point loading using a displacement-controlled testing machine.The test results showed that ECC beams can mostly withstand higher cracking and ultimate loads compared to their corresponding normal concrete versions.The results also showed that both the ductility and toughness of the ECC beams are higher than those of the normal concrete beams and that the ductility values of the hollow beams with a hole size of 60 mm are higher than those of the corresponding solid beams.Moreover,hollow ECC beams with hole sizes of 60 and 80 mm exhibited a higher ductility than a solid normal concrete beam.
基金supported by the National Natural Science Foundation of China (Grant No. KB92009)
文摘The far-field propagation properties of conical double half-Gaussian hollow beams in the condition of Collins formula are studied. Because of the cone angle of this kind of hollow beams, the diffraction is compensated and the inner diameter is turning bigger by the rule of geometric optics as the propagation distance is increasing, whereas the degenerating diffraction phenomenon is turned out. The far-field intensity distribution of the conical double half-Gaussian hollow beams in the condition of in-Collins formula is researched, and the results show that the far-field propagation properties can be depicted by this model. In the experiment, this kind of hollow beams are obtained by means of the dual-reflecting splitting optical system, and the inner diameter of the hollow beams is tested. The results show good agreement with the propagation theory in the condition of in-Collins formula.
基金Supported by the National Natural Science Foundation of China (Grant No.KB92009)
文摘A new kind of hollow beams, double half-Gaussian hollow beams,was put forward. With the help of the Collins formula, the analytical equation of propagation and transformation of the hollow laser beams in free space was deduced. The simulation shows that the intensity exhibits the three-dimensional trap distribution in the near-field, while the double half-Gaussian hollow beams turn into solid laser beams when propagating a certain distance, which shows the characteristics of self-focus. The double half-Gaussian hollow beams were obtained by means of the dual-reflecting splitting optical system. The intensity of the vertical loop in different distances was tested, which shows that the analytical equation of propagation and transformation is in agreement with the result.
基金Project supported by National Natural Science Foundation of China (Grant Nos. 10804033 and 10674050)Program for Innovative Research Team of Higher Education of Guangdong Province of China (Grant No. 06CXTD005)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 200805740002)the Natural Science Foundation of Hebei Province of China (Grant No. F2009000321)
文摘The propagation of hollow Gaussian beams in strongly nonlocal nonlinear media is studied in detail. Two analytical expressions are derived. For hollow Gaussian beams, the intensity distribution always evolves periodically. However the second-order moment beam width can keep invariant during propagation if the input power is equal to the critical power. The interaction of two hollow Gaussian beams and the vortical hollow Gaussian beams are also discussed. The vortical hollow Gaussian beams with an appropriate topological charge can keep their shapes invariant during propagation.
文摘The use of the sand concrete makes it possible to carry out a concrete having physico-mechanical properties answering the structural exigences and having economic and environmental advantages compared to the classical concrete. The present study aims to connecting the parameters of a formulation based on an empirical formula of Caquot in order to optimize, on the one hand the couple compressive strength/absorption of water under various degrees of hygrometry, and on the other hand more precisely to use the concrete sand in the public works sector in the prefabrication of prestressed beams and hollow bricks. The results show the importance of the type of formulation used because it takes into account the percentages of fillers of sand which is a co-product (waste) of massive rock crushing. In addition, the use of fillerized sands, which are wastes of crushing basaltic rocks and containing a small percentage of fillers, is efficient in the manufacture of prestressed beams. As for the hollow bricks, a fillerized basalt sand, containing a high percentage of filler, as well as a sand dune, gives satisfactory results.
文摘In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.