Accelerating ferroic ageing dynamics upon cooling

Once a structural glass is formed, its relaxation time will increase exponentially with decreasing temperature. Thus, the glass has little chance of transforming into a crystal upon further cooling to zero Kelvin. However, a spontaneous transition upon cooling from amorphous to long-range ordered ferroic states has been observed experimentally in ferroelastic, ferroelectric and ferromagnetic materials. The origin for this obvious discrepancy is discussed here conceptually. We present a combined theoretical and numerical study of this phenomenon and show that the diffusive and displacive atomic processes that take place in structural glass and amorphous ferroics, respectively, lead to markedly different temperature-dependent relaxation behaviors, one being ‘colder is slower’ and the other being ‘colder is faster’.National Basic Research Program of China (2012CB619402)National Basic Research Program of China (2014CB644003)National Key Basic Research Program of China (51671156)National Basic Research Program of China 111 Project (B06025)National Science Foundation (U.S.). Division of Materials Research (DMR-1410322)National Science Foundation (U.S.). Division of Materials Research (DMR-1410636

Use of confinement and additives to control inorganic crystallization

This thesis describes the investigation of the three minerals, calcium sulfate, calcium phosphate and calcium carbonate under two bio-inspired methods, additives and confinement. The first experiment in Chapter 3 investigated the precipitation pathway of calcium sulfate above and under the solubility levels. Two metastable phases were obtained at ambient condition, hemihydrate and amorphous calcium sulfate (ACS), that first revealed hemihydrate can be found in room temperature and the existence of ACS. The transformation of ACS to the most stable phase, gypsum via hemihydrate was also proved under the titration and Cryo-TEM at undersaturated solution. Chapter 4 deals with the investigation of calcium sulfate grown in the presence of additives. These additives which have the profound inhibition effect provide another evidence of the existence of hemihydrate and ACS in the ambient conditions. Neglected before in literature, the morphology change of gypsum and hemihydrate also provide an aggregation-based transformation from hemihydrate to gypsum. Similar results were obtained growing calcium carbonate in confinement allowing formation of amorphous calcium carbonate. The results in Chapter 5 also demonstrated that confinement plays a significant role in the formation not only of the amorphous phase, but also the metastable phase, hemihydrate. Results were obtained in the absence and presence of the additives that lead to stabilize hemihydrate and ACS for more than 24 hours. Precipitation of calcium phosphate in confinement in the absence and presence of the additives used the same method as mentioned in the previous chapter. Similar results were obtained and again demonstrated that confinement and additives play a more significant role in bone formation. The last chapter investigated the crystallization pathway of calcium carbonate under UV-Vis at 2-10 mM concentration solutions with/without additives. The in-situ experiment in Chapter 7 provides a simple method to investigate the influence of concentrations of calcium carbonate solution and additives. Amorphous calcium carbonate nanoparticles were formed at early stage which transformed to stable calcite with tim

Liver fatty acid composition in mice with or without nonalcoholic fatty liver disease

<p>Abstract</p> <p>Background</p> <p>Nonalcoholic fatty liver disease (NAFLD) is one of the most frequent causes of abnormal liver function. Because fatty acids can damage biological membranes, fatty acid accumulation in the liver may be partially responsible for the functional and morphological changes that are observed in nonalcoholic liver disease. The aim of this study was to use gas chromatography-mass spectrometry to evaluate the fatty acid composition of an experimental mouse model of NAFLD induced by high-fat feed and CCl₄and to assess the association between liver fatty acid accumulation and NAFLD. C57BL/6J mice were given high-fat feed for six consecutive weeks to develop experimental NAFLD. Meanwhile, these mice were given subcutaneous injections of a 40% CCl₄-vegetable oil mixture twice per week.</p> <p>Results</p> <p>A pathological examination found that NAFLD had developed in the C57BL/6J mice. High-fat feed and CCl₄led to significant increases in C14:0, C16:0, C18:0 and C20:3 (P < 0.01), and decreases in C15:0, C18:1, C18:2 and C18:3 (P < 0.01) in the mouse liver. The treatment also led to an increase in SFA and decreases in other fatty acids (UFA, PUFA and MUFA). An increase in the ratio of product/precursor n-6 (C20:4/C18:2) and n-3 ([C20:5+C22:6]/C18:3) and a decrease in the ratio of n-6/n-3 (C20:4/[C20:5+C22:6]) were also observed.</p> <p>Conclusion</p> <p>These data are consistent with the hypothesis that fatty acids are deranged in mice with non-alcoholic fatty liver injury induced by high-fat feed and CCl₄, which may be involved in its pathogenesis and/or progression via an unclear mechanism.</p

Image restoration and key field alignment for misaligned overlapping text in secondary printing document images

With the advancement of information technology, the demand for efficient recognition and information extraction from paper documents in industrial scenarios has grown rapidly. In practice, business information is often secondarily printed onto pre-designed templates, which frequently leads to text misalignment or overlap with backgrounds and tables, thereby significantly impairing the accuracy of subsequent Optical Character Recognition (OCR). To address this issue, this paper proposes a preprocessing method for OCR recognition of secondary printed documents, specifically targeting the problems of text misalignment and overlap. In particular, we design a Text Overlap Restoration Network (TORNet) to restore document images affected by text overlap. Experimental results demonstrate that, compared to the latest image restoration models, TORNet achieves PSNR improvements of 0.17 dB and 0.12 dB in foreground and background text restoration, respectively. Furthermore, to resolve residual misalignment issues after image restoration, a key-field alignment method is introduced. This method accurately locates the positional deviations of critical fields in the reconstructed image, enabling precise field-level alignment and structural correction. Based on the proposed preprocessing framework, the recognition accuracy and field-matching accuracy are improved by 23% and 31%, respectively, compared to existing commercial OCR models, significantly enhancing the recognition performance on misaligned and overlapping documents. This study provides an effective solution for recognizing secondary printed documents with text overlap in industrial environments

Optimal Control Strategy with Efficiency and Reliability Improvement for Offshore DC Microgrids

Offshore microgrids, due to their remote location and lack of external energy support, face significant challenges in wide-range load operation and maintenance. Consequently, efficiency and reliability are critical concerns for converters in offshore dc microgrids. This article presents an optimal control strategy aimed at enhancing both efficiency and reliability. A normalized nonlinear relationship between power loss and thermal stress of a paralleled converter is first established. Based on this, a dual-objective optimization function with an active weight function as well as a system overall performance index is established. The active weight function dynamically adjusts the control priority based on converter efficiency and switching device thermal stress. Then, the optimal power-sharing strategy is derived by the Lagrange multiplier method with the proposed optimal function. Additionally, to accommodate a wide load range, an optimal selection strategy for operating converter combinations is proposed, requiring only low-bandwidth communication. Experiment verification is given to validate the effectiveness of the proposed control strategy. The experiment results demonstrate that the proposed control strategy can improve the overall performance of offshore microgrids by optimizing efficiency and reliability.</p