60 research outputs found
Dicylopentadienyl[4-(4-vinylbenzyloxy)pyridine-2,6-dicarboxylato]titanium(IV) monohydrate
The title compound, [Ti(C5H5)2(C16H11NO5)]·H2O, exhibits a titanocene unit coordinated to a styrene-substituted pyridine-2,6-dicarboxylate ligand synthesized for use as a monomer for polymerization or copolymerization yielding metallocene-containing polymers. The compound crystallized as a monohydrate and the solvent water molecule forms strong O—H⋯O hydrogen bonds with the carboxylate O atoms of the Ti complex, which play an important role in the connection of adjacent molecules. In addition, weak intermolecular C—H⋯O hydrogen bonds also contribute to the crystal packing arrangement
Minimal Cut Sets-Based Reliability Evaluation of the More Electric Aircraft Power System
The More Electric Aircraft (MEA) stands for the direction of aviation development in the new era, and the reliability of power systems on the MEA has attracted widespread attention. Based on the characteristics of MEA power systems, an equivalent method of electrical topology structure is presented in this article, and evaluation method is proposed which shows the reliability of the overall system with the reliability of specific nodes. Firstly, electrical topology structure of a MEA power system is converted into a network node diagram according to the proposed equivalent method. Then, the minimal path sets of specific nodes are obtained by the adjacent matrix algorithm, and the low-order minimal cut sets of disjointed are obtained. After that, the actual failure rate of components is converted to node failure rate, and the reliability of the overall system is evaluated by operational reliability indexes of specific nodes. Finally, taking the MEA A380 as an example, this paper compares and analyzes the reliability of AC loads, DC loads, and key loads to verify the validity and feasibility of the proposed evaluation method. This evaluation system can predict the weak points existing in the MEA power system, as well as providing theoretical support for maintenance schedule
Assessment of the Impact of Land Use Change on Spatial Differentiation of Landscape and Ecosystem Service Values in the Case of Study the Pearl River Delta in China
Industrialization and urbanization have led to continuous urban development. The rapid change in land-use type and extent has a significant impact on the capacity of ecosystem services. Changes in the landscape pattern of roads, rivers, railway stations, and expressway entrances and exits have evident geographical proximity effects. We used landscape pattern indices and ecosystem service value (ESV) to evaluate the landscape pattern and ESV spatial differentiation of the Pearl River Delta region and its typical transportation infrastructure and rivers in 1990, 2000, and 2017. The results show that rapid urbanization and industrialization have led to changes in urban land use along the Pearl River Estuary. Urban land changes on the east bank of the Pearl River are greater than urban land changes on the west bank of the Pearl River; the landscape diversity of the Pearl River Delta has increased, the connectivity of the landscape has decreased, and the degree of fragmentation has increased. Second, the city size of the Pearl River Delta was negatively correlated with the ESVs. The ESVs in the core areas of the Pearl River Delta urban agglomeration were smaller than those in the fringe areas. With the gradient change in urban land use, ESVs showed a growing trend from the city center to the surrounding areas. The key areas for ecological protection and restoration should be central urban areas and suburbs. Third, the siphoning effect of the buffer zones of railway stations and expressway entrances and exits was very strong and drove the development and utilization of the surrounding land. As the degree of land development in the buffer zone decreased, the ESVs increased. Fourth, different grades of roads in the Pearl River Delta had different impacts on the regional landscape and ESVs. County roads had a greater interference effect than expressways, national roads, and provincial roads, and the riverside plains of the Pearl River Delta have a large development space, low urban development costs, and multiple land-use activities that have profoundly changed the landscape of the river buffer zone
Assessment of the Impact of Land Use Change on Spatial Differentiation of Landscape and Ecosystem Service Values in the Case of Study the Pearl River Delta in China
Industrialization and urbanization have led to continuous urban development. The rapid change in land-use type and extent has a significant impact on the capacity of ecosystem services. Changes in the landscape pattern of roads, rivers, railway stations, and expressway entrances and exits have evident geographical proximity effects. We used landscape pattern indices and ecosystem service value (ESV) to evaluate the landscape pattern and ESV spatial differentiation of the Pearl River Delta region and its typical transportation infrastructure and rivers in 1990, 2000, and 2017. The results show that rapid urbanization and industrialization have led to changes in urban land use along the Pearl River Estuary. Urban land changes on the east bank of the Pearl River are greater than urban land changes on the west bank of the Pearl River; the landscape diversity of the Pearl River Delta has increased, the connectivity of the landscape has decreased, and the degree of fragmentation has increased. Second, the city size of the Pearl River Delta was negatively correlated with the ESVs. The ESVs in the core areas of the Pearl River Delta urban agglomeration were smaller than those in the fringe areas. With the gradient change in urban land use, ESVs showed a growing trend from the city center to the surrounding areas. The key areas for ecological protection and restoration should be central urban areas and suburbs. Third, the siphoning effect of the buffer zones of railway stations and expressway entrances and exits was very strong and drove the development and utilization of the surrounding land. As the degree of land development in the buffer zone decreased, the ESVs increased. Fourth, different grades of roads in the Pearl River Delta had different impacts on the regional landscape and ESVs. County roads had a greater interference effect than expressways, national roads, and provincial roads, and the riverside plains of the Pearl River Delta have a large development space, low urban development costs, and multiple land-use activities that have profoundly changed the landscape of the river buffer zone
Ultra-short-term wind power prediction based on copula function and bivariate EMD decomposition algorithm
Against the background of increasing installed capacity of wind power in the
power generation system, high-precision ultra-short-term wind power prediction is significant for safe and reliable operation of the power generation system. We present a method
for ultra-short-term wind power prediction based on a copula function, bivariate empirical
mode decomposition (BEMD) algorithm and gated recurrent unit (GRU) neural network.
First we use the copula function to analyze the nonlinear correlation between wind power
and external factors to extract the key factors influencing wind power generation. Then the
joint data composed of the key factors and wind power are decomposed into a series of
stationary subsequence data by a BEMD algorithm which can decompose the bivariate data
jointly. Finally, the prediction model based on a GRU network uses the decomposed data as
the input to predict the power output in the next four hours. The experimental results show
that the proposed method can effectively improve the accuracy of ultra-short-term wind
power prediction
The Effects of Insulin-Like Growth Factor-1 and Basic Fibroblast Growth Factor on the Proliferation of Chondrocytes Embedded in the Collagen Gel Using an Integrated Microfluidic Device
This work presents an integrated microfluidic device on which the proliferation of rabbit chondrocytes was investigated in the presence of insulin-like growth factor-1 (IGF-1), basic fibroblast growth factor (bFGF), and their combinations. The microfluidic device was mainly composed of an upstream concentration gradient generator and a downstream perfusion-based three-dimensional cell culture module. The rabbit articular chondrocytes were cultured for 2 weeks at the different concentrations of growth factors generated by concentration gradient generator. IGF-1, up to 57.14 ng/mL, had the ability to promote the proliferation of chondrocytes in a dose-dependent manner, and there were no further promotions at higher concentrations. bFGF increased chondrocyte proliferation dose dependently up to 5.72 ng/mL, and then the proliferation rate decreased when the concentration was increased. The combination of IGF-1 and bFGF could synergistically promote the proliferation, and the group of 85.73 ng/mL IGF-1 and 1.43 ng/mL bFGF presented an optimal effect (up to 4.76-fold), which had statistically significant differences compared with IGF-1 and bFGF, respectively. Moreover, the proliferation test using the conventional method was performed simultaneously and revealed similar results. The results obtained in this study demonstrated that the microfluidic device is an effective platform for cartilage tissue engineering. With this device, experimental conditions are flexible and can be optimized by changing either the category of growth factors or the concentration of input growth factor. Further, the small number of cells (1-100) required, with which parallel experiments could be performed simultaneously, makes it an attractive platform for the high-through screening at the cellular level in autologous chondrocyte implantation
Low-Carbon Development for the Iron and Steel Industry in China and the World: Status Quo, Future Vision, and Key Actions
The low-carbon development of China’s iron and steel industry (ISI) is important but challenging work for the attainment of China’s carbon neutrality by 2060. However, most previous studies related to the low-carbon development of China’s ISI are fragmented from different views such as production-side mitigation, demand-side mitigation, or mitigation technologies. Additionally, there is still a lack of a comprehensive overview of the long-term pathway to the low-carbon development of China’s ISI. To respond to this gap and to contribute to better guide policymaking in China, this paper conducted a timely and comprehensive review following the technology roadmap framework covering the status quo, future vision, and key actions of the low-carbon development of the world and China’s ISI. First, this paper provides an overview of the technology roadmap of low-carbon development around the main steel production countries in the world. Second, the potential for key decarbonization actions available for China’s ISI are evaluated in detail. Third, policy and research recommendations are put forward for the future low-carbon development of China’s ISI. Through this comprehensive review, four key actions can be applied to the low-carbon development of China’s ISI: improving energy efficiency, shifting to Scrap/EAF route, promoting material efficiency strategy, and deploying radical innovation technologies
Low-Carbon Development for the Iron and Steel Industry in China and the World: Status Quo, Future Vision, and Key Actions
The low-carbon development of China’s iron and steel industry (ISI) is important but challenging work for the attainment of China’s carbon neutrality by 2060. However, most previous studies related to the low-carbon development of China’s ISI are fragmented from different views such as production-side mitigation, demand-side mitigation, or mitigation technologies. Additionally, there is still a lack of a comprehensive overview of the long-term pathway to the low-carbon development of China’s ISI. To respond to this gap and to contribute to better guide policymaking in China, this paper conducted a timely and comprehensive review following the technology roadmap framework covering the status quo, future vision, and key actions of the low-carbon development of the world and China’s ISI. First, this paper provides an overview of the technology roadmap of low-carbon development around the main steel production countries in the world. Second, the potential for key decarbonization actions available for China’s ISI are evaluated in detail. Third, policy and research recommendations are put forward for the future low-carbon development of China’s ISI. Through this comprehensive review, four key actions can be applied to the low-carbon development of China’s ISI: improving energy efficiency, shifting to Scrap/EAF route, promoting material efficiency strategy, and deploying radical innovation technologies
- …