This paper examines The Herald newspaper＇s role in safeguarding the seemingly unparalleled longevity of Zimbabwe＇s ruling Zimbabwe African National Union-Patriotic Front （ZANU-PF） party. Through an analysis of a s...This paper examines The Herald newspaper＇s role in safeguarding the seemingly unparalleled longevity of Zimbabwe＇s ruling Zimbabwe African National Union-Patriotic Front （ZANU-PF） party. Through an analysis of a sample of stories from both the paper＇s print and online editions, the study traces the origins of the broadsheet＇s ostensibly unflagging pro-ZANU-PF editorial positions, turning to article analysis to critically probe not only the motive but also the impact of the newspaper＇s assumed open allegiance to the revolutionary party. In a nation believed battered by perceived state brutality and widening political differences, The Herald has been accused of significantly influencing the pace of dictatorship while guardedly manipulating information to prop up President Robert Mugabe＇s party. So important has the paper become over the years that its often uncompromising, one-sided style of reporting has earned it praise among militant ZANU-PF hardliners while bitterly attracting widespread criticism from critics of the long-serving party.展开更多
AC and DC breakdown tests were performed on large populations of oil-impregnated pressboard samples. The effect of voltage ramp rate on dielectric strength has been investigated. A statistical analysis of breakdown da...AC and DC breakdown tests were performed on large populations of oil-impregnated pressboard samples. The effect of voltage ramp rate on dielectric strength has been investigated. A statistical analysis of breakdown data was carried out using the Weibull distribution. The 90% confidence intervals of Weibull graphs were calculated. The study shows that dielectric strength and shape parameter change versus ramp rate. The variations are attributed to the size and number of defects. Discharges occur from the oil to the oil-pressboard interface and lead to breakdown. DC dielectric strength is larger than that corresponding to AC voltage. This is ascribed to the dissipated energy difference under the two types of field and the fatigue produced by the alternating voltage. This phenomenon is related to space charge. Under DC stress, dielectric strength is higher under negative polarity. It is assigned to the different quantities of space charge accumulated under the two polarities.展开更多
A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the d...A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the distribution of fiber orientation. The effect of flow-fiber coupling is considered by modifying the constitutive mode.The three-dimensional orientation distribution function is formulated and the corresponding equations are solved in terms of second-order and fourth-order orientation tensors. The evolution of fiber orientation, flow velocity and pressure, additional shear stress and normal stress difference are presented. The results show that the evolutions of fiber orientation are different along different streamlines. The velocity and its gradient are large in the concave wall region, while they are very small in the convex wall region. The additional shear stress and normal stress difference are large in the inlet and concave wall regions, and moderate in the mid-region, while they are almost zero in most downstream regions. The non-equilibrium fiber orientation distribution is dominant at the inlet and the concave wall regions. The flow will consume more energy to overcome the additional shearing losses due to fibers at the inlet and the concave wall regions. The change of flow rates has effect on the distribution of additional shear stress and normal stress difference. The flow structure in the inlet and concave wall regions is essential in the resultant rheological properties of the fiber suspension through the stock pump impeller, which will directly affect the flow efficiency of the fiber suspension through the impeller.展开更多
This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consen...This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consensus problem of missiles＇ time-to-go estimates, this paper formulates it as the consensus problem of missiles＇ ranges-to-go. Based on this strategy, novel distributed guidance laws are proposed to solve the simultaneous attack problem with the target of unknown maneuverability.Adaptive control method is introduced to estimate the upper bound of the target＇s acceleration. The effectiveness of the proposed guidance laws is verified both theoretically and numerically.展开更多
文摘This paper examines The Herald newspaper＇s role in safeguarding the seemingly unparalleled longevity of Zimbabwe＇s ruling Zimbabwe African National Union-Patriotic Front （ZANU-PF） party. Through an analysis of a sample of stories from both the paper＇s print and online editions, the study traces the origins of the broadsheet＇s ostensibly unflagging pro-ZANU-PF editorial positions, turning to article analysis to critically probe not only the motive but also the impact of the newspaper＇s assumed open allegiance to the revolutionary party. In a nation believed battered by perceived state brutality and widening political differences, The Herald has been accused of significantly influencing the pace of dictatorship while guardedly manipulating information to prop up President Robert Mugabe＇s party. So important has the paper become over the years that its often uncompromising, one-sided style of reporting has earned it praise among militant ZANU-PF hardliners while bitterly attracting widespread criticism from critics of the long-serving party.
文摘AC and DC breakdown tests were performed on large populations of oil-impregnated pressboard samples. The effect of voltage ramp rate on dielectric strength has been investigated. A statistical analysis of breakdown data was carried out using the Weibull distribution. The 90% confidence intervals of Weibull graphs were calculated. The study shows that dielectric strength and shape parameter change versus ramp rate. The variations are attributed to the size and number of defects. Discharges occur from the oil to the oil-pressboard interface and lead to breakdown. DC dielectric strength is larger than that corresponding to AC voltage. This is ascribed to the dissipated energy difference under the two types of field and the fatigue produced by the alternating voltage. This phenomenon is related to space charge. Under DC stress, dielectric strength is higher under negative polarity. It is assigned to the different quantities of space charge accumulated under the two polarities.
基金Supported by the National Natural Science Foundation of China （51309118）, the National Key Technology R＆D Program of the Ministry of Science and Technology of China （2011BAF14B01）, the Postdoctoral Science Foundation of China （2013M531282） and the Doctorate Program of Higher Education of China （20120101110121）.
文摘A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the distribution of fiber orientation. The effect of flow-fiber coupling is considered by modifying the constitutive mode.The three-dimensional orientation distribution function is formulated and the corresponding equations are solved in terms of second-order and fourth-order orientation tensors. The evolution of fiber orientation, flow velocity and pressure, additional shear stress and normal stress difference are presented. The results show that the evolutions of fiber orientation are different along different streamlines. The velocity and its gradient are large in the concave wall region, while they are very small in the convex wall region. The additional shear stress and normal stress difference are large in the inlet and concave wall regions, and moderate in the mid-region, while they are almost zero in most downstream regions. The non-equilibrium fiber orientation distribution is dominant at the inlet and the concave wall regions. The flow will consume more energy to overcome the additional shearing losses due to fibers at the inlet and the concave wall regions. The change of flow rates has effect on the distribution of additional shear stress and normal stress difference. The flow structure in the inlet and concave wall regions is essential in the resultant rheological properties of the fiber suspension through the stock pump impeller, which will directly affect the flow efficiency of the fiber suspension through the impeller.
基金supported by the National Natural Science Foundation of China under Grant Nos.61473005,11332001,and 61471242the Research Project Fund under Grant No.17-163-11-ZT-003-018-01+2 种基金the Air Force Advance Research Fund under Grant No.303020503the Joint Fund of Equipment development and Aerospace Science and Technology under Grant No.6141B0624050101the National Defense Basic Scientific Research Program(Major)of China
文摘This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consensus problem of missiles＇ time-to-go estimates, this paper formulates it as the consensus problem of missiles＇ ranges-to-go. Based on this strategy, novel distributed guidance laws are proposed to solve the simultaneous attack problem with the target of unknown maneuverability.Adaptive control method is introduced to estimate the upper bound of the target＇s acceleration. The effectiveness of the proposed guidance laws is verified both theoretically and numerically.
