Two-dimensional Noncommutative atom Gas with Anandan interaction

Landau like quantization of the Anandan system in a special electromagnetic field is studied. Unlike the cases of the AC system and the HMW system, the torques of the system on the magnetic dipole and the electric dipole don't vanish. By constructing Heisenberg algebra, the Landau analog levels and eigenstates on commutative space, NC space and NC phase space are obtained respectively. By using the coherent state method, some statistical properties of such free atom gas are studied and the expressions of some thermodynamic quantities related to revolution direction are obtained. Two particular cases of temperature are discussed and the more simple expressions of the free energy on the three spaces are obtained. We give the relation between the value of $\sigma$ and revolution direction clearly, and find Landau like levels of the Anandan system are invariant and the levels between the AC system and the HMW system are interchanged each other under Maxwell dual transformations on the three spaces. The two sets of eigenstates labelled by $\sigma$ can be related by a supersymmetry transformation on commutative space, but the phenomenon don't occur on NC situation. We emphasize that some results relevant to Anandan interaction are suitable for the cases of AC interaction and HMW interaction under special conditions.Comment: Latex, 10 page

PISA and PISA for ‘development’: an inquiry into the OECD’s expansion into low- and middle-income countries

This thesis analyses PISA-D to understand its origins, the legitimation strategies which frame it, and its outcomes. The thesis begins by locating PISA-D within the evolution of OECD after the 1950s. That story, which is told briefly, is one of successful expansion. More specifically, as the global education agenda was being changed after 2015 to emphasise minimum standards of quality for all countries to be delivered by 2030, the OECD has been seeking to expand its most successful policy instrument – PISA – to include low- and middle-income countries. In 2013, it introduced PISA for Development (PISA-D) to help promote PISA as a universal measure of learning. In 2018 the results of PISA-D were released, and in 2019 it was declared a success by OECD. Clearly PISA-D has the potential to have a significant impact on various aspects of education in low-income countries. To explore these themes, this thesis was guided by a number of research questions which included: what are the origins of PISA-D and how have they shaped its contemporary form? How has PISA-D been promoted and what strategies have been employed by OECD to establish a clear role for itself in monitoring Sustainable Development Goal 4? How has PISA-D addressed the challenges that low- and middle-income countries face in engaging in PISA and what policy insights does it provide for the piloting countries? The basic approach of the thesis is through documentary research, but this was supplemented by semi-structured interviews and secondary analysis of the literature. The work has permitted new interpretations of the contributions of OECD to global educational governance, has highlighted the legitimation strategies of OECD as it expands its role, and has made clearer how the PISA-D countries are construed as backward – and as needing to learn from other, especially high-performing, countries participating in PISA

Analysis of Turbulence on Cylinder with Additional Fairing with Free Surface

In this study, two dimensional unsteady flows of cylinder and cylinder with additional fairing close to a free surface were numerically investigated. The governing momentum equations were solved by using the Semi Implicit Method for Pressure Linked Equations(SIMPLE). The Volume of Fluid(VOF) method applied to simulate a free surface. Non- uniform grid structures were used in the simulation with denser grids near the cylinder. Under the conditions of Reynolds number 150624, 271123, 210874 and 331373, the cylinders were simulated with different depths of invasion. It was shown that the flow characteristics were influenced by submergence depth and Reynolds numbers. When the cylinder close to the free surface, the drag coefficient, lift coefficient and Strouhal numbers will increase due to the effect of free liquid surface on vortex shedding. With additional fairing, can effectively reduce the influence of the free surface on the drag coefficient. Fairing will reduce lift coefficient at high Reynolds numbers, but increase lift coefficient when Reynolds numbers are small. Fairing can effectively reduce Strouhal numbers, thus can well suppress the vortex induced vibratio

Enhancing quantum entropy in vacuum-based quantum random number generator

Information-theoretically provable unique true random numbers, which cannot be correlated or controlled by an attacker, can be generated based on quantum measurement of vacuum state and universal-hashing randomness extraction. Quantum entropy in the measurements decides the quality and security of the random number generator. At the same time, it directly determine the extraction ratio of true randomness from the raw data, in other words, it affects quantum random numbers generating rate obviously. In this work, considering the effects of classical noise, the best way to enhance quantum entropy in the vacuum-based quantum random number generator is explored in the optimum dynamical analog-digital converter (ADC) range scenario. The influence of classical noise excursion, which may be intrinsic to a system or deliberately induced by an eavesdropper, on the quantum entropy is derived. We propose enhancing local oscillator intensity rather than electrical gain for noise-independent amplification of quadrature fluctuation of vacuum state. Abundant quantum entropy is extractable from the raw data even when classical noise excursion is large. Experimentally, an extraction ratio of true randomness of 85.3% is achieved by finite enhancement of the local oscillator power when classical noise excursions of the raw data is obvious.Comment: 12 pages,8 figure