32 research outputs found

    In Situ X-ray Absorption Spectroscopy of Metal/Nitrogen-doped Carbons in Oxygen Electrocatalysis

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    Metal/nitrogen-doped carbons (M−N−C) are promising candidates as oxygen electrocatalysts due to their low cost, tunable catalytic activity and selectivity, and well-dispersed morphologies. To improve the electrocatalytic performance of such systems, it is critical to gain a detailed understanding of their structure and properties through advanced characterization. In situ X-ray absorption spectroscopy (XAS) serves as a powerful tool to probe both the active sites and structural evolution of catalytic materials under reaction conditions. In this review, we firstly provide an overview of the fundamental concepts of XAS and then comprehensively review the setup and application of in situ XAS, introducing electrochemical XAS cells, experimental methods, as well as primary functions on catalytic applications. The active sites and the structural evolution of M−N−C catalysts caused by the interplay with electric fields, electrolytes and reactants/intermediates during the oxygen evolution reaction and the oxygen reduction reaction are subsequently discussed in detail. Finally, major challenges and future opportunities in this exciting field are highlighted.</p

    Evaluating the impact of decentralising tuberculosis microscopy services to rural township hospitals in gansu province, china

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    <p>Abstract</p> <p>Background</p> <p>In 2004, the Ministry of Health issued the policy of decentralising microscopy services (MCs) to one third of all township hospitals in China. The study was conducted in Gansu Province, a poor western one in China. Ganzhou was one county in Gansu Province. Ganzhou County was identified as a unique case of further decentralisation of tuberculosis (TB) treatment services in township hospitals. The study evaluated the impact of the MC policy on providers and patients in Gansu Province. The second objective was to assess the unique case of Ganzhou County compared with other counties in the province.</p> <p>Methods</p> <p>Both quantitative and qualitative methods were used. All 523 MCs in the province completed an institutional survey regarding their performance. Four counties were selected for in-depth investigation, where 169 TB suspects were randomly selected from the MC and county TB dispensary registers for questionnaire surveys. Informant interviews were conducted with 38 health staff at the township and county levels in the four counties.</p> <p>Results</p> <p>Gansu established MCs in 39% of its township hospitals. From January 2006 to June 2007, 8% of MCs identified more than 10 TB sputum smear positive patients while 54% did not find any. MCs identified 1546 TB sputum smear positive patients, accounting for 9% of the total in the province. The throughputs of MCs in Ganzhou County were eight times of those in other counties. Interviews identified several barriers to implement the MC policy, such as inadequate health financing, low laboratory capacity, lack of human resources, poor treatment and management capacities, and lack of supervisions from county TB dispensaries.</p> <p>Conclusion</p> <p>Microscopy centre throughputs were generally low in Gansu Province, and the contribution of MCs to TB case detection was insignificant taking account the number of MCs established. As a unique case of full decentralisation of TB service, Ganzhou County presented better results. However, standards and quality of TB care needed to be improved. The MC policy needs to be reviewed in light of evidence from this study.</p

    Design accuracy and magnetic field analysis of a dual-armature bearingless flux reversal motor

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    A dual-armature bearingless flux reversal motor (DBFRM) is proposed. The permanent magnet in the motor is located on the stator side, the armature winding is located on the stator side and the rotor side, the suspension winding is located at the stator side, the rotor teeth are embedded in the slotted non-magnetic material rotor barrel, and the stator and rotor cores are made of laminated silicon steel. The DBFRM demonstrates the characteristics of high speed, long life, and fast dynamic response and has unique advantages in power energy saving and energy storage. Compared with the traditional bearingless flux reversal motor, the DBFRM shows better fault tolerance. Based on the theory of air-gap magnetic field modulation, the torque and the levitation mechanism of the motor are expounded from four perspectives—permanent magnetic field, armature reaction magnetic field, electromagnetic torque, and levitation force—which lays the foundation for the establishment of an accurate mathematical model of levitation force and torque

    Joint optimisation of transfer location and capacity for a capacitated multimodal transport network with elastic demand: a bi-level programming model and paradoxes

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    With the growing attention toward developing a multimodal transport system to enhance urban mobility, there is an increasing need to construct new infrastructures, rebuild or expand the existing ones, to accommodate the current and newly generated travel demand. Therefore, this study develops a bi-level model that simultaneously determines the location and capacity of the transfer infrastructure to be built considering the elastic demand in a multimodal transport network. The upper-level problem is formulated as a mixed-integer linear programming problem, whereas the lower-level problem is a combined trip distribution/modal split/assignment model that depicts both the destination and route choices of travellers via a multinomial logit model. Numerical studies are conducted to demonstrate the occurrence of two Braess-like paradox phenomena in a multimodal transport network. The first one states that under fixed demand, constructing new parking spaces to provide the usage of park-and-ride services could deteriorate the system performance measured by the total passengers’ travel time, while the second one reveals that under elastic demand, increasing the parking capacity for park-and-ride services to promote its usage may fail, which would be represented by the decline in their modal share. Meanwhile, a numerical example also suggests that constructing transfer infrastructures at distributed stations outperforms building a large transfer centre in terms of attracting travellers using sustainable transit modes

    3D Cadastre Oriented Reconstruction of Administrative Procedure in Chinese Urban Land Management

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    Focusing on the recent management problem of 3D land utilization in the administrative procedure in China, this paper firstly elaborates the basic characteristics of land ownership and management in China, and then introduces the main concepts and steps in the current urban land management procedure, and reveals the deficiency in supporting 3D utilization for urban regions. Finally, from the perspective of 3D space and regarding 3D cadaster management as the core, this paper presents new administrative procedure of urban land management reconstructed from the recent procedure

    Exploring efficient and effective generative adversarial network for thermal infrared image colorization

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    Abstract Thermal infrared image colorization is very difficult, and colorized images suffer from poor texture detail recovery and low color matching. To solve the above problems, this paper proposes an Efficient and Effective Generative Adversarial Network (E2GAN). This paper proposes multi-level dense module, feature fusion module, and color-aware attention module in the improved generator. Adding multi-level dense module can enhance the feature extraction capability and the improve detail recovery capability Using the feature fusion module in the middle of the encoder–decoder reduces the information loss caused by encoder down-sampling and improves the prediction of fine color of the image. Using the color-aware attention module during up-sampling allows for capturing more semantic details, focusing on more key objects, and generating high-quality colorized images. And the proposed discriminator is the PatchGAN with color-aware attention module, which enhances its ability to discriminate between true and false colorized images. Meanwhile, this paper proposes a novel composite loss function that can improve the quality of colorized images, generate fine local details, and recover semantic and texture information. Extensive experiments demonstrate that the proposed E2GAN has significantly improved SSIM, PSNR, LPIPS, and NIQE on the KAIST dataset and the FLIR dataset compared to existing methods

    LASNet: A Light-Weight Asymmetric Spatial Feature Network for Real-Time Semantic Segmentation

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    In recent years, deep learning models have achieved great success in the field of semantic segmentation, which achieve satisfactory performance by introducing a large number of parameters. However, this achievement usually leads to high computational complexity, which seriously limits the deployment of semantic segmented applications on mobile devices with limited computing and storage resources. To address this problem, we propose a lightweight asymmetric spatial feature network (LASNet) for real-time semantic segmentation. We consider the network parameters, inference speed, and performance to design the structure of LASNet, which can make the LASNet applied to embedded devices and mobile devices better. In the encoding part of LASNet, we propose the LAS module, which retains and utilize spatial information. This module uses a combination of asymmetric convolution, group convolution, and dual-stream structure to reduce the number of network parameters and maintain strong feature extraction ability. In the decoding part of LASNet, we propose the multivariate concatenate module to reuse the shallow features, which can improve the segmentation accuracy and maintain a high inference speed. Our network attains precise real-time segmentation results in a wide range of experiments. Without additional processing and pre-training, LASNet achieves 70.99% mIoU and 110.93 FPS inference speed in the CityScapes dataset with only 0.8 M model parameters
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