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825 results on '"Qiu, Guoping"'

223. Investigation of the Absorption Properties of the Alloys Fe-Ni and Fe-Ni-Cr Prepared by Mechanical Alloying

Author

Duan Yuping, Gu Shuchao, Wang Song, Qiu Guoping, Duan Peng, and Liu Yuzhe

Subjects
Permittivity, Materials science, Solid-state physics, Scanning electron microscope, Metallurgy, Reflection loss, Alloy, engineering.material, Condensed Matter Physics, Microstructure, Electronic, Optical and Magnetic Materials, Permeability (electromagnetism), Materials Chemistry, engineering, Dielectric loss, Electrical and Electronic Engineering, Composite material
Abstract

The microwave-absorption properties and microstructures of Fe-Ni and Fe-Ni-Cr alloys prepared by mechanical alloying were investigated in the frequency range 2–18 GHz. Other properties were studied by scanning electron microscopy, x-ray diffractometry, vibrating sample magnetometry, and transmission line theory. Dependence of reflection loss (RL), electromagnetic properties (permeability μ and permittivity e), magnetic and dielectric loss tangent, impedance matching, and absorber thickness (d) on milling time is discussed. The alloy powders had excellent microwave-absorption properties in the frequency range 7 to 14 GHz. The minimum RL, the frequency at which the RL is minimum, and the bandwidth (RL

Published
2015

225. Extracting activity patterns from taxi trajectory data: a two-layer framework using spatio-temporal clustering, Bayesian probability and Monte Carlo simulation.

Author

Gong, Shuhui, Cartlidge, John, Bai, Ruibin, Yue, Yang, Li, Qingquan, and Qiu, Guoping

Subjects
MONTE Carlo method, GLOBAL Positioning System, CITY dwellers, PROBABILITY theory
Abstract

Global positioning system (GPS) data generated from taxi trips is a valuable source of information that offers an insight into travel behaviours of urban populations with high spatio-temporal resolution. However, in its raw form, GPS taxi data does not offer information on the purpose (or intended activity) of travel. In this context, to enhance the utility of taxi GPS data sets, we propose a two-layer framework to identify the related activities of each taxi trip automatically and estimate the return trips and successive activities after the trip, by using geographic point-of-interest (POI) data and a combination of spatio-temporal clustering, Bayesian inference and Monte Carlo simulation. Two million taxi trips in New York, the United States of America, and ten million taxi trips in Shenzhen, China, are used as inputs for the two-layer framework. To validate each layer of the framework, we collect 6,003 trip diaries in New York and 712 questionnaire surveys in Shenzhen. The results show that the first layer of the framework performs better than comparable methods published in the literature, while the second layer has high accuracy when inferring return trips. [ABSTRACT FROM AUTHOR]

Published
2020
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226. Enhancing remote sensing image retrieval using a triplet deep metric learning network.

Author

Cao, Rui, Zhang, Qian, Zhu, Jiasong, Li, Qing, Li, Qingquan, Liu, Bozhi, and Qiu, Guoping

Subjects
IMAGE retrieval, ARTIFICIAL neural networks, DEEP learning, REMOTE sensing, SIMILARITY (Geometry)
Abstract

With the rapid growing of remotely sensed imagery data, there is a high demand for effective and efficient image retrieval tools to manage and exploit such data. In this letter, we present a novel content-based remote sensing image retrieval (RSIR) method based on Triplet deep metric learning convolutional neural network (CNN). By constructing a Triplet network with metric learning objective function, we extract the representative features of the images in a semantic space in which images from the same class are close to each other while those from different classes are far apart. In such a semantic space, simple metric measures such as Euclidean distance can be used directly to compare the similarity of images and effectively retrieve images of the same class. We also investigate a supervised and an unsupervised learning methods for reducing the dimensionality of the learned semantic features. We present comprehensive experimental results on two public RSIR datasets and show that our method significantly outperforms state-of-the-art. [ABSTRACT FROM AUTHOR]

Published
2020
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247. Adult-onset Nemaline Myopathy Coexisting With Myasthenia Gravis

Author

Cao, Lingling, Wang, Yanling, Liu, Xiaofeng, Hu, Yanxia, Li, Nianchun, Qiu, Guoping, Luo, Yun, and Li, Weidong

Subjects
Male, Muscle Weakness, Myasthenia Gravis, Humans, Clinical Case Report, Middle Aged, Myopathies, Nemaline, Research Article
Abstract

Myasthenia gravis (MG) is an autoimmune neuromuscular junction disorder which is characterized by fluctuating muscle fatigue. However, the association of MG with nemaline myopathy is rarely reported. Here we report a case of MG coexisting with adult-onset nemaline myopathy. A 55-year-old man endured fluctuating muscle weakness with positive acetylcholine receptor and titin antibodies. After the patient was administrated cholinergic drugs and immunosuppression, the muscle weakness of the patient had mildly been alleviated. Electromyography showed a progressive decrement in the amplitude of muscle action potential at low frequency. Muscle biopsy showed numerous nemalines in the muscle fibers. This is the first reported case of nemalines present in the muscle fibers of adult patient with MG. The pathogenesis of nemaline may be related to titin antibody in adult-onset nemaline myopathy with MG.

Published
2016

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