This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are es...This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.展开更多
Rotating bed can be used in desorption operation of biogas upgrading as a new technology. For enough time to desorb, it is important to study the relationship between the residence time of liquid in rotating bed and t...Rotating bed can be used in desorption operation of biogas upgrading as a new technology. For enough time to desorb, it is important to study the relationship between the residence time of liquid in rotating bed and the material diffusion time of liquid droplet in desorption process. By theoretical deduction, the exponential relation between residence time and liquid flow rate and rotational speed and kinematic viscosity is obtained. By analyzing the solution of nonlinear partial differential equation, the time law of material diffusion in the droplet is obtained. Moreover, by comparing the residence and diffusion times, the diffusion time can be within or out of residence time range, which has a direct relationship to rotational speed and liquid flow. By experiment, the comparison between residence and diffusion times is more realistic when the rotational speed is higher.展开更多
The present work aimed to investigate the microscopic and ultramicro- scopic structure of the liver to assess the level of hepatic impairment during preg- nancy toxemia. Seven pregnant small-tailed Han sheep of negati...The present work aimed to investigate the microscopic and ultramicro- scopic structure of the liver to assess the level of hepatic impairment during preg- nancy toxemia. Seven pregnant small-tailed Han sheep of negative urine ketone bodies were assessed in this study. Toxemia was induced by limiting food and movement tate in pregnancy. Three sheep developed obvious clinical symptoms with motor weakness, depression, anorexia, locomotion disturbances, blindness and lan- guishment. We harvested their liver tissues as pathological material, and used rou- tine histological and electronic microscopy methods to observe the histopathological changes in small-tailed Han sheep induced by pregnancy toxemia. Autopsy of the livers of the sheep revealed deep yellow coloration, intumescence and hemorrhage on the surface. Microstructural features indicated fatty degeneration, which is a main characteristic of fatty liver. Hepatocellular ultrastructural changes were observed un- der an electronic microscope. The characteristic findings were nucieolus concentra- tion, vacuolation of mitochondria and excessive glycogen granules in the cytoplasm. Via this experimental protocol, pregnancy toxemia of sheep was successfully in- duced, providing a pathological model for the study of this disease. After the experi- mental induction of pregnancy toxemia, the clinical symptoms of pathogenic sheep and pathological changes to their livers exhibited obvious characteristics of pregnan- cy toxemia.展开更多
文摘This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.
基金Supported by the Special Scientific Research Fund of Agricultural Public Welfare Profession of China(201303099)
文摘Rotating bed can be used in desorption operation of biogas upgrading as a new technology. For enough time to desorb, it is important to study the relationship between the residence time of liquid in rotating bed and the material diffusion time of liquid droplet in desorption process. By theoretical deduction, the exponential relation between residence time and liquid flow rate and rotational speed and kinematic viscosity is obtained. By analyzing the solution of nonlinear partial differential equation, the time law of material diffusion in the droplet is obtained. Moreover, by comparing the residence and diffusion times, the diffusion time can be within or out of residence time range, which has a direct relationship to rotational speed and liquid flow. By experiment, the comparison between residence and diffusion times is more realistic when the rotational speed is higher.
基金Supported by Natural Science Foundation of Ningxia(BA002-2004)
文摘The present work aimed to investigate the microscopic and ultramicro- scopic structure of the liver to assess the level of hepatic impairment during preg- nancy toxemia. Seven pregnant small-tailed Han sheep of negative urine ketone bodies were assessed in this study. Toxemia was induced by limiting food and movement tate in pregnancy. Three sheep developed obvious clinical symptoms with motor weakness, depression, anorexia, locomotion disturbances, blindness and lan- guishment. We harvested their liver tissues as pathological material, and used rou- tine histological and electronic microscopy methods to observe the histopathological changes in small-tailed Han sheep induced by pregnancy toxemia. Autopsy of the livers of the sheep revealed deep yellow coloration, intumescence and hemorrhage on the surface. Microstructural features indicated fatty degeneration, which is a main characteristic of fatty liver. Hepatocellular ultrastructural changes were observed un- der an electronic microscope. The characteristic findings were nucieolus concentra- tion, vacuolation of mitochondria and excessive glycogen granules in the cytoplasm. Via this experimental protocol, pregnancy toxemia of sheep was successfully in- duced, providing a pathological model for the study of this disease. After the experi- mental induction of pregnancy toxemia, the clinical symptoms of pathogenic sheep and pathological changes to their livers exhibited obvious characteristics of pregnan- cy toxemia.
