Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anis...Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported.A new concept of simple anisotropic fluid was introduced.On the basis of anisotropic principle,the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory.Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced.More general model LCP-H for the fluid was developed.The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids.The influence of the relaxation times on material functions was specially studied.It is important to study the unsteady vibrational rotating flow with small amplitudes,as it is a best way to obtain knowledge of elasticity of the LC polymer,i.e.dynamic viscoelasticity.For the shear-unsymmetric stresses,two shear stresses were obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author.For the two stability problems of fluid,such as stability of hydrodynamic flow and orientational motion,were discussed.The results show that the polymer suspension systems exhibit anisotropic character.The PNC systems can exhibit significant shear-thinning effects.For more concentrated polymer nano-suspensions,the first normal stress difference change from positive to negative,which is similar to LC polymer behavior.展开更多
基于深度学习的方法在图像超分辨重建任务中已经取得了显著突破。它们成功的关键在于依赖大量成对的低分辨率和高分辨率图像来训练超分辨模型。然而,众所周知,获取如此大量一一对应的真实高-低分辨率图像对是一个具有挑战性的任务。且...基于深度学习的方法在图像超分辨重建任务中已经取得了显著突破。它们成功的关键在于依赖大量成对的低分辨率和高分辨率图像来训练超分辨模型。然而,众所周知,获取如此大量一一对应的真实高-低分辨率图像对是一个具有挑战性的任务。且基于仿真图像对训练的模型在面对具有与训练集退化类型不同的图像时往往表现不佳。在本文中,我们提出了用于单帧图像超分辨重建的自监督图像扩散模型(Self-supervised Diffusion Model for Single Image Super-resolution,SSDM-SR)来突破数据集的限制,从而避免这些问题。该方法基于扩散模型来学习单帧图像内的信息分布,并为待超分辨重建的图像训练一个小型的特定图像扩散模型。训练数据集仅从待超分辨图像本身中提取,因此SSDM-SR可以适应不同的输入图像。另外,该方法引入了坐标信息以帮助构建出图像的整体框架,从而使模型收敛更快。在多个公开基准数据集和具有未知退化核的数据集上的实验表明,SSDM-SR不仅在图像失真度方面优于近期先进的有监督和无监督图像超分辨重建方法,并且能生成具有更高感知质量的图像。在真实世界低分辨率图像上,它也生成了视觉上令人满意且无明显伪影的结果。展开更多
基金Project(10772177) supported by the National Natural Science Foundation of China
文摘Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported.A new concept of simple anisotropic fluid was introduced.On the basis of anisotropic principle,the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory.Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced.More general model LCP-H for the fluid was developed.The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids.The influence of the relaxation times on material functions was specially studied.It is important to study the unsteady vibrational rotating flow with small amplitudes,as it is a best way to obtain knowledge of elasticity of the LC polymer,i.e.dynamic viscoelasticity.For the shear-unsymmetric stresses,two shear stresses were obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author.For the two stability problems of fluid,such as stability of hydrodynamic flow and orientational motion,were discussed.The results show that the polymer suspension systems exhibit anisotropic character.The PNC systems can exhibit significant shear-thinning effects.For more concentrated polymer nano-suspensions,the first normal stress difference change from positive to negative,which is similar to LC polymer behavior.
文摘基于深度学习的方法在图像超分辨重建任务中已经取得了显著突破。它们成功的关键在于依赖大量成对的低分辨率和高分辨率图像来训练超分辨模型。然而,众所周知,获取如此大量一一对应的真实高-低分辨率图像对是一个具有挑战性的任务。且基于仿真图像对训练的模型在面对具有与训练集退化类型不同的图像时往往表现不佳。在本文中,我们提出了用于单帧图像超分辨重建的自监督图像扩散模型(Self-supervised Diffusion Model for Single Image Super-resolution,SSDM-SR)来突破数据集的限制,从而避免这些问题。该方法基于扩散模型来学习单帧图像内的信息分布,并为待超分辨重建的图像训练一个小型的特定图像扩散模型。训练数据集仅从待超分辨图像本身中提取,因此SSDM-SR可以适应不同的输入图像。另外,该方法引入了坐标信息以帮助构建出图像的整体框架,从而使模型收敛更快。在多个公开基准数据集和具有未知退化核的数据集上的实验表明,SSDM-SR不仅在图像失真度方面优于近期先进的有监督和无监督图像超分辨重建方法,并且能生成具有更高感知质量的图像。在真实世界低分辨率图像上,它也生成了视觉上令人满意且无明显伪影的结果。
