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Establishment of a new tropospheric delay correction model over China area

science China(Physics,Mechanics & Astronomy) 2011年第12期54卷 2271-2283页

作者： sONG shuLi ZHU WenYao CHEN QinMing liou YueiAn shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Center for space and Remote sensing Research National Central University Taiwan China

The tropospheric delay is one of the main error sources for radio navigation technologies and other ground-or space-based earth observation systems. In this paper, the spatial and temporal variations of the zenith tropospheric delay (ZTD), especially their dependence on altitude over China region, are analyzed using ECMWF (European Centre for Medium-Range Weather Forecast) pressure-level atmospheric data in 2004 and the ZTD series in 1999-2007 measured at 28 GPs stations from the Crustal Movement Observation Network of China (CMONC). A new tropospheric delay correction model (sHAO) is derived and a regional realization of this model for China region named sHAO-C is established. In sHAO-C model, ZTD is modeled directly by a cosine function together with an initial value and an amplitude at a reference height in each grid, and the variation of ZTD along altitude is fitted with a second-order polynomial. The coefficients of sHAO-C are generated using the meteorology data in China area and given at two degree latitude and longitude interval, featuring regional characteristics in order to facilitate a wide range of navigation and other surveying applications in and around China. Compared with the EGNOs (European Geostationary Navigation Overlay service) model, which has been used globally and recommended by the European Union Wide Area Augmentation system, the ZTD prediction (in form of spatial and temporal projection) accuracy of the sHAO-C model is significantly improved over China region, especially at stations of higher altitudes. The reasons for the improvement are: (1) the reference altitude of sHAO-C parameters are given at the average height of each grid, and (2) more detailed description of complicated terrain variations in China is incorporated in the model. Therefore, the accumulated error at higher altitude can be reduced considerably. In contrast, the ZTD has to be calculated from the mean sea level with EGNOs and other models. Compared with the direct estim

关键词： EGNOs GPs tropospheric delay sHAO-C model ECMWF pressure-level data

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A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： s.sAURABH R.KIRAN D.sINGH R.VAIsH V.s.CHAUHAN school of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHsDT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(HR), helicoidal exponential(HE), helicoidal semi-circular(Hs), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

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semantic segmentation of Lumbar Vertebrae Using Meijering U-Net(MU-Net)on spine Magnetic Resonance Images

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Computer Modeling in Engineering & sciences 2025年第1期142卷 733-757页

作者： Lakshmi s V V shiloah Elizabeth Darmanayagam sunil Retmin Raj Cyril Department of Computer science and Engineering College of Engineering GuindyAnna UniversityChennai600025India Department of Information Technology Madras Institute of TechnologyAnna UniversityChrompetChennai600044India

Lower back pain is one of the most common medical problems in the world and it is experienced by a huge percentage of people *** to its ability to produce a detailed view of the soft tissues,including the spinal cord,nerves,intervertebral discs,and vertebrae,Magnetic Resonance Imaging is thought to be the most effective method for imaging the *** semantic segmentation of vertebrae plays a major role in the diagnostic process of lumbar *** is difficult to semantically partition the vertebrae in Magnetic Resonance Images from the surrounding variety of tissues,including muscles,ligaments,and intervertebral discs.U-Net is a powerful deep-learning architecture to handle the challenges of medical image analysis tasks and achieves high segmentation *** work proposes a modified U-Net architecture namely MU-Net,consisting of the Meijering convolutional layer that incorporates the Meijering filter to perform the semantic segmentation of lumbar vertebrae L1 to L5 and sacral vertebra ***-colour mask images were generated and used as ground truth for training the *** work has been carried out on 1312 images expanded from T1-weighted mid-sagittal MRI images of 515 patients in the Lumbar spine MRI Dataset publicly available from Mendeley *** proposed MU-Net model for the semantic segmentation of the lumbar vertebrae gives better performance with 98.79%of pixel accuracy(PA),98.66%of dice similarity coefficient(DsC),97.36%of Jaccard coefficient,and 92.55%mean Intersection over Union(mean IoU)metrics using the mentioned dataset.

关键词： Computer aided diagnosis(CAD) magnetic resonance imaging(MRI) semantic segmentation lumbar vertebrae deep learning U-Net model

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Predicting Maximum Lifespan Limits at Mean Menopausal Age

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Journal of Mathematical Research with Applications 2025年第1期 133-142页

作者： M.sUMATHI s.ANTONY CARLA Department of Mathematics N.M.S.S.Vellaichamy Nadar College Research scholar (Part-time) Madurai Kamaraj University

The age at which a woman enters natural menopause has also been associated to death from any cause. Menopause is a natural component of aging that happens between the ages of 45 and 55, with the average menopausal age being 51. Previous research has revealed the age at which women reach menopause, but there is no evidence to support the link between menopause and longevity. We made a study in assessing the limits of maximum lifespan at menopausal age in our previous article. In this paper, we aim to predict the maximum lifespan of women at mean menopausal age.

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synthesis and characterization of Cu-Pt/MWCNTs for use in electrocatalytic applications

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Particuology 2011年第5期9卷 522-527页

作者： Yuh-Jing Chiou Hang-Jui Hsu Hong-Ming Lin Wei-Jen liou Huey-Wen liou she-Huang Wu shu-Hua Chien Department of Materials Engineering Tatung University 40 Chungshan N. Rd. 3rd Sec 104 Taipei Taiwan China Institute of Chemistry Academia Sinica 128Academia Road Sec. 2 Nankang 115 Taipei Taiwan China

Improving catalyst performance by studying the preparation parameters, material structures and analysis methods is important work for catalyst researchers. In this study, Cu-Pt nanocomposites with different metal ratios were synthesized on MWCNTs using a polyol method. The structures and morphologies of the nano hybrid catalysts were analyzed by XRD and TEM. The XRD results indicate that Pt and Cu formed a bimetallic solid solution. The average diameters of the Pt and Cu-Pt nanoparticles on MWCNTs were between 3-10 nm and 5-15 nm, respectively. The electrocatalytic behavior of methanol oxidation reactions was investigated by cyclic voltammery （CV）. Cu（20%）/[Pt/MWCNTs（1：4）], which contained an optimal degree of solid solution, enhanced the methanol oxidation to the greatest degree.

关键词： Electrocatalysis Methanol Multi-walled carbon nanotubes NanoparticlesPlatinumCopper

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The Interaction Effects of the Parameters on Optimization Design in Paper Production Waste Usage on Alkali-Activated slag with Taguchi Method

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Journal of Renewable Materials 2022年第6期10卷 1753-1772页

作者： Teng Yi shuenn-Ren liou Wen-Yih Kuo National Cheng Kung University Tainan70100Taiwan Lotos Tainan70255Taiwan

The paper investigates the second-order interactions of parameters in an alkali-activated mixture of paper production waste(PPW)and blast furnace slag(BFs)in Taguchi *** PPW including lime mud(LM)and paper sludge(Ps).This paper provides the experimental models to assess the compressive and flexural strength of them at 7-day and *** results have shown that the second-order interactions between PPW and alkali-activated activator exists in each experimental model,and the significant interactions affect the selection of optimal *** with the interactions between the PPW themselves,the interactions between PPW and alkali-activated parameters are the main significant factors affecting its physical *** each experimental model,the maximum compressive strength was 47.41 MPa in 7-day and 65.64 MPa in *** with the confirmatory experiments,the deviation of prediction calculated by experimental models was 3.08%and 0.56%,*** maximum flexural strength was 5.74 MPa in 7-day and 5.96 MPa in 28-day;compared with the confirmatory experiments,the deviation of prediction calculated by experimental models was 5.40%and 0.17%.Considering the influence of circular materials,30%of PPW should be a suitable ratio to replace BFs as the raw material of alkali-activated slag(AAs).

关键词： Paper production waste alkali-activated slag taguchi method interactions of parameters experimental model

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Proactive interburden fracturing using UIs drilling with validation monitoring

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International Journal of Mining science and Technology 2021年第1期31卷 3-7页

作者： adam Lines Anglo American Grosvenor MineMoranbah 4744Australia

A series of gas inrush events occurred during development at Grosvenor Mine resulting in exposure to elevated levels of methane at the production face.A total of 22 gas inrush events occurred,with between 15 and 130 m3 of methane released during each *** presence of an undrained seam in the immediate floor,geotechnical characteristics of the floor,and the stress environment all contributed to these dynamic floor events,while the geological characteristics of the seam below,such as the seam thickness and ash content of 75%,prevented effective ***,events only occurred in headings mined parallel to the principal horizontal stress *** cut-throughs(C/T)perpendicular to the principal stress direction no events occurred,and higher methane levels were observed at the production *** solution to preventing the gas inrush events involved creating a conduit in the interburden between the mined seam and the seam in the immediate floor to allow the gas to be drained during the development of the headings,as occurred in the cut-throughs(cut-through and cross-cut are regional terms that are analogous).A series of underground inseam(UIs)holes were drilled using the directional drill rig with the aim of fracturing this interburden ahead of the face and promote floor failure to allow the gas to release *** floor fracturing was conducted using water pressure generated from a longwall salvage pump,with the current UIs drilling equipment retrofitted with a series of subs,packers and a fracturing *** packers and the fracturing tool were shifted to desired locations along the drilled UIs borehole to achieve the required *** fractures were monitored using a proving hole and with a HYDAC data logger attached to the salvage pack,with the results analysed on the surface to ensure connectivity to the working seam.

关键词： Gas drainage Floor fracking UIs drilling

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Gasification of lignite from Polish coal mine to hydrogen-rich gas

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International Journal of Coal science & Technology 2022年第6期9卷 151-160页

作者： adam smolinski slawomir Wochna Natalia Howaniec Central Mining Institute Plac Gwarkow 140-166 KatowicePoland PGE Górnictwo i Energetyka Konwencjonalna s.A. Oddz.Kopalnia Wegla Brunatnego TurówGórników Turowa 159-916 BogatyniaPoland Department of Energy saving and Air Protection Central Mining InstitutePlac Gwarkow 140-166 KatowicePoland

The efforts of the world research activities involved in clean coal technologies development focus to a considerable extent on integrated hydrogen and power generation technologies based on coal *** an alternative to combustion pro-cesses,gasification offers increased efficiency,lower negative environmental impact as well as wider application range of the main product—synthesis gas—in power generation and chemical *** order to select the most optimal lignite for the purpose of gasification,it is necessary to determine coal reactivity,the key parameter characterizing how fast the fuel reacts with the gasifying medium and controlling its process ability in thermochemical conversion to energy and/or energy *** paper presents the experimental results of oxygen/steam gasification of lignite coal char in a fixed bed reactor under atmospheric pressure and at the temperature of 700,800 and 900℃;the samples come from an open pit lignite mine in the southwest of *** effectiveness of the gasification process was tested in terms of the total gas and hydrogen yields,gas composition,carbon conversion rate and chars reactivity.

关键词： Coal gasification Hydrogen syngas Clean coal technologies

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Economics-based Principles for a Post-conflict China-Us Commercial Regime

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China & World Economy 2018年第5期26卷 2-11页

作者： adam s. Posen Peterson Institute for Intemational Economics

Neither the Chinese nor Us economic systems will fundamentally change as a result of overt trade conflict. The challenge for policy-relevant economics is to design a regime for China-Us commerce that accepts the co-existence but also addresses underlying disputes. Many important China-Us disputes, notably those over intellectual property protection and state subsidies, cannot be resolved by the World Trade Organization, thus new institutions must be built. Economics-based regime principles should entail recognition that： the China-Us bilateral trade imbalance is unique mainly because of macroeconomic and financial factors, not trade; agreements should restrict commercial and government behaviors, not target economic outcomes; Chinese companies must compete and be allowed to succeed in any sector, including high-technology; China is not entitled to Us-owned technology, thus intellectual property rights must be enforced; and the Us Government should support an increased role for China in global economic governance.

关键词： China-Us relations commercial policy high-technology competition trade conflict

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semiconducting Carbon Nanotube/Fullerene Blended Heterojunctions for Photovoltaic Near-Infrared Photon Harvesting

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Nano Research 2011年第11期4卷 1174-1179页

作者： Dominick J. Bindl adam s. Brewer Michael s. Arnold 1509 University Ave. Materials Science and Engineering Dept. University of Wisconsin-Madison Madison WI 53706 USA

We demonstrate that the near-infrared （NIR） absorptivity of semiconducfing single-walled carbon nanotubes （s-sWCNTs） can be harnessed in blended heterojunctions with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）. Photogenerated charge separation is efficiently driven by the ultrahigh interracial area of the blends and the favorable energy offsets between the two materials. NIR-sensitive photovoltaic and photodetector devices utilizing the stack （indium tin oxide/ca. 10 nm s-sWCNT：PCBM/100 nm CJ10 nm 2,9- dimethyl-4,7-diphenyl-],10-phenanthroline （BCP）/Ag） were fabricated with NIR power conversion efficiencies 〉1.3% and peak, zero bias external quantum efficiency of 18% at λ = 1205 nm.

关键词： Carbon nanotube bulk heterojunction photovoltaic photodetector near-infrared (NIR)

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