Between Centralization and Decentralization: Changed Curriculum Governance in Chinese Education after 1986

China’s curriculum system has been undergoing substantial transformations since 1986. In response to public criticism of the highly prescribed national curriculum, the central state of China is attempting to build a more inclusive system which is composed of national curriculum, province curriculum and school-based curriculum. The new curriculum system accommodates more flexibility in carrying out national curriculum policies and even encourages local input in curriculum development and management. Apparently, the current curriculum reform in China is moving toward decentralization. The purpose of this work is to demonstrate the complexity of decentralization reform in China’s curriculum system and examine the dynamics of policy formulation and outcomes of reform efforts in great depth. The main argument made in this socio-philosophical work is that the on-going Chinese curriculum reform is a process of centralized decentralization, which merely transfers work to the local level but not real authority. With an inquiry into the impetus of current Chinese curriculum reform, this theoretical research illustrates that centralized decentralization is taken as a strategic imperative by the state to avoid loss of control over school curriculum that carries particular social and political significance for China in a transitional period. Another major task for this cultural studies research is to problematize the strategy of centralized decentralization, investigating the consequences of the superficial decentralization in reality and analyzing the bottlenecks in promoting current Chinese curriculum reform. In this research, Mark Hanson’s conceptual framework of education decentralization is used to clarify ambiguity in defining decentralization reform in the education sector in China. Meanwhile, Foucault’s theory about power/knowledge and governmentality and Williams’ theory about hegemony are used to deepen the understanding of the state-education relationship in contemporary China. Besides a descriptive analysis of phenomena in current Chinese curriculum reform, the discussion is deployed through pragmatic approach and logic-based reasoning. Most data are obtained from literature review, including previous studies on Chinese education reform, government documents, laws and regulations related to current Chinese curriculum reform

First-Principles and Molecular Dynamics Studies of Ferroelectric Oxides: Designing New Materials for Novel Applications

In recent years, there has been an increasing demand for materials that can serve for a variety of technological applications, such as nonvolatile ferroelectric random access memory for computers, SONAR sensor device for military vehicles, dielectric materials for telecommunication, and photovoltaic materials for solar energy conversion. In this thesis, we present computational studies of a special class of complex oxides. Specifically, we studied perovskite ferroelectric materials with the general chemical formula ABO3, where A and B correspond to different chemical species. Using computational and theoretical tools, we started our search for novel materials by improving our understanding of how the microscopic chemistry and physics determine the macroscopic properties of materials that have been previously synthesized and characterized. Thus, having validated our computational methods, we used those to predict novel materials with superior properties and further developed some general rules and guidelines for the design of novel materials. Depending on the specific problem at hand, we used either ab initio density functional theory (DFT) or classical molecular dynamics (MD) modeling.First, we employed ab initio DFT to investigate the material Bi(Zn1/2Ti1/2)O3 (BZT), which is considered to be good analogue of the more commonly used PbTiO3. Although PbTiO3 is ubiquitously used, a lead free ceramics, such as Bi(Zn1/2Ti1/2)O3, is desirable due to environmental concerns. Our results confirm the material\u27s superior large cation displacement and tetragonal distortion compared to PbTiO3, but also indicate that the conventional electrostatic model (for determining the most favored cation ordering) should be corrected under special lattice geometric circumstances. As the tetragonal distortion increases, the electrostatic contribution to the total energy decreases, rendering other interaction forces relatively more important in determining the ordering of cations. Inspired by our work on BZT, we continued to develop a guideline for designing ferroelectric materials with similar lattice parameters (high tetragonality). Traditionally, Landau-Ginzburg-Devonshire (LGD) theory has been considered a powerful tool for studying ferroelectrics, which relies on the polarization (P) as the order parameter. However, the lack of LGD parameters limits the utility of LGD theory when applied to novel materials with compositional variation, requiring the development of an alternative design rule. To this end, we began by carefully choosing a group of PbTiO3-derived solid solutions. By extracting the essential geometric information (ionic displacement and strain) as well as the polarization of the solutions, we discovered a very good linear correlation between B-cation displacement squared and strain for all 25 solid solutions, suggesting that the B-cation displacement is a more natural order parameter rather than the polarization of the material. Furthermore, we found that the magnitude of the ionic displacement is mostly affected by both the ion covalency and the ion sizes, allowing us to increase the B-cation displacement by substituting the B-site with either a small-size cation or the small fraction of a large-size cation surrounded by rigid TiO6 neighbors. The advances we made in this work contribute a significant piece to the big picture of understanding the relationships between different microscopic and macroscopic properties for perovskite ferroelectrics. Next, we turned our attention to the electronic structures for those highly tetragonal ferroelectric materials that we studied so far only the structural properties. We chose three target materials, namely Bi(Zn1/2Ti1/2)O3, Bi(Zn3/4W1/4)O3 and Bi(Zn3/4Mo1/4)O3. All of these materials have two types of B-cations. Different local chemistries, including B-cation ordering, lattice strain, cation identity and oxygen cage O6 tilt, affect the electronic band gap structure. We found that the cation ordering effect most profoundly affects electronic band gaps in these materials, which also changes the carrier mobility accordingly. More importantly, we discovered that by reorienting the polarization direction by 90o, the band gap can be altered by as much as 0.6 eV. This result highlights the possibility of using a single chemical composition compound for multi-junction solar energy conversion. By arranging cations differently at different layers, different layers would absorb different frequencies of photons of the solar spectrum. Finally, we utilized a classical bond-valence model (BVMD) to trace the ferroelectric material\u27s fast dynamics under external perturbations, such as electric field or strain field. One of our studies is about the polarization switching dynamics of the prototypical perovskite ferroelectric PbTiO3, by coherently controlling the collective structural change. A specially shaped terahertz electric field pulse train is pumped to resonate with a particular IR-active phonon mode. We proved that the atoms in the crystal could move collectively from the initial domain orientation to the opposite one during a very short time period (15 ps), suggesting a new time scale for ultrafast ``read\u27\u27 and ``write\u27\u27 speed in computers equipped with ferroelectric non-volatile random access memory. Also, we employed MD simulations to study the domain wall nucleation dynamics under an external strain field. The 90o domain wall width is observed to be around one or two lattice constants thick, consistent with other DFT studies, high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM) experiments. A very interesting antisymmetry at the wall was revealed with atomic scale details. Our preliminary data for the domain wall nucleation process shows a good match with Merz\u27s law. Additional 90o domain wall nucleation under strain dynamics studies are currently under investigation

Adiponectin improves coronary no-reflow injury by protecting the endothelium in rats with type 2 diabetes mellitus.

To determine the effect of adiponectin (APN) on the coronary no-reflow (NR) injury in rats with Type 2 diabetes mellitus (T2DM), 80 male Sprague-Dawley rats were fed with a high-sugar-high-fat diet to build a T2DM model. Rats received vehicle or APN in the last week and then were subjected to myocardial ischemia reperfusion (MI/R) injury. Endothelium-dependent vasorelaxation of the thoracic aorta was significantly decreased and serum levels of endothelin-1 (ET-1), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were noticably increased in T2DM rats compared with rats without T2DM. Serum APN was positively correlated with the endothelium-dependent vasorelaxation, but negatively correlated with the serum level of ET-1. Treatment with APN improved T2DM-induced endothelium-dependent vasorelaxation, recovered cardiac function, and decreased both NR size and the levels of ET-1, ICAM-1 and VCAM-1. Hypoadiponectinemia was associated with the aggravation of coronary NR in T2DM rats. APN could alleviate coronary NR injury in T2DM rats by protecting the endothelium and improving microcirculation

Reassessment of the evolution of wheat chromosomes 4A, 5A, and 7B.

Key messageComparison of genome sequences of wild emmer wheat and Aegilops tauschii suggests a novel scenario of the evolution of rearranged wheat chromosomes 4A, 5A, and 7B. Past research suggested that wheat chromosome 4A was subjected to a reciprocal translocation T(4AL;5AL)1 that occurred in the diploid progenitor of the wheat A subgenome and to three major rearrangements that occurred in polyploid wheat: pericentric inversion Inv(4AS;4AL)1, paracentric inversion Inv(4AL;4AL)1, and reciprocal translocation T(4AL;7BS)1. Gene collinearity along the pseudomolecules of tetraploid wild emmer wheat (Triticum turgidum ssp. dicoccoides, subgenomes AABB) and diploid Aegilops tauschii (genomes DD) was employed to confirm these rearrangements and to analyze the breakpoints. The exchange of distal regions of chromosome arms 4AS and 4AL due to pericentric inversion Inv(4AS;4AL)1 was detected, and breakpoints were validated with an optical Bionano genome map. Both breakpoints contained satellite DNA. The breakpoints of reciprocal translocation T(4AL;7BS)1 were also found. However, the breakpoints that generated paracentric inversion Inv(4AL;4AL)1 appeared to be collocated with the 4AL breakpoints that had produced Inv(4AS;4AL)1 and T(4AL;7BS)1. Inv(4AS;4AL)1, Inv(4AL;4AL)1, and T(4AL;7BS)1 either originated sequentially, and Inv(4AL;4AL)1 was produced by recurrent chromosome breaks at the same breakpoints that generated Inv(4AS;4AL)1 and T(4AL;7BS)1, or Inv(4AS;4AL)1, Inv(4AL;4AL)1, and T(4AL;7BS)1 originated simultaneously. We prefer the latter hypothesis since it makes fewer assumptions about the sequence of events that produced these chromosome rearrangements

Application of Multi-Beam Sounding System in the Monitoring of Pile Foundation Erosion of Offshore Wind Turbines

[Introduction] The purpose is to study the influence of tidal current and wave on the sub-aqueous foundation of wind turbine in offshore wind farm. [Method] Through two seabed topography surveys, the changes of seabed topography were compared. [Result] The study shows that the erosion of the foundation of offshore wind turbines mainly occur in the direction of local tides. In the early stage of construction, a deep scour pit will be formed, and scour troughs will appear after two years, and siltation will appear around the foundation after the scour troughs are formed. [Conclusion] Long-term monitoring of the foundation erosion of offshore wind turbines is helpful to understand the changes in the extent and depth of erosion. Hydrological surveys will help to establish ocean hydrodynamic models to predict the foundation erosion of wind turbines. Measures such as rock dumping and solidified soil should be carried out for erosion filling to delay the occurrence of erosion