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Finite-difference time-domain studies of low-frequency stop band in superconductor-dielectric superlattice

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作者： joshua~le-wei~li Zhi Wang Katherine Zheng Institute of Electromagnetics and School of Electronic Engineering University of Electronic Science and Technology of China School of Engineering Monash University

A vertical antenna radiation in the presence of a sphere such as the earth has been a common problem in many science and engineering *** resulted electric and magnetic fields in such a geometry are usually expressed in terms of the spherical vector wave functions,regardless of whether the sphere is perfectly electric conducting or lossy *** the electromagnetic fields can be obtained analytically,numerical discontinuity exists in the closed form solutions of the direct wave radiated,which forms the well known Gibbs *** the past many years,this problem was left over there and it resulted a lot of concerns and questions when the numerical results of electromagnetic fields were *** several some attempts were tried to use numerical approaches to overcome this *** this work,an analytic removal of the Gibbs phenomenon is proposed and *** this simple approach,all the field components can be obtained analytically and *** results can be widely applied to accurate numerical solutions to various problems in physics,engineering,chemistry,biology etc.

关键词： Discontinuity Dipole antennas Convergence of numerical methods Series(mathematics) Earth Electromagnetic wave propagation

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Chinese Physics B 2010年第8期19卷 374-378页

作者：王身云刘少斌 le-wei joshua li College of Information Science and Technology Nanjing University of Aeronautics & Astronautics Department of Electrical and Computer Engineering National University of Singapore

The transmission coefficients of electromagnetic （EM） waves due to a superconductor-dielectric superlattice are numerically calculated. Shift operator finite difference time domain （SO-FDTD） method is used in the analysis. By using the SO-FDTD method, the transmission spectrum is obtained and its characteristics are investigated for different thicknesses of superconductor layers and dielectric layers, from which a stop band starting from zero frequency can be apparently observed. The relation between this low-frequency stop band and relative temperature, and also the London penetration depth at a superconductor temperature of zero degree are discussed, separately. The low-frequency stop band properties of superconductor-dielectric superlattice thus are well disclosed.

关键词： shift operator finite difference time domain method superconductor superconductor- dielectric superlattice high-pass filter

A Q-band CMOS LNA exploiting transformer feedback and noise-cancelling

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Science China(Information Sciences) 2015年第4期58卷 148-157页

作者： WU Jing JIANG ZhengDong YI Kai KANG Kai YU YiMing CHEN JiXin ZHANG lei liU Jun li le-wei joshua School of Economic Information Engineering Southwestern University of Finance and Economics School of Electronic Engineering University of Electronic Science and Technology of China State Key Laboratory of Millimeter Waves Southeast University Institute of Microelectronics Tsinghua University Key Laboratory of RF Circuits and Systems Hangzhou Dianzi University School of Engineering Monash University

In this paper, a Q-band CMOS low noise amplifier(LNA) exploiting transformer positive-negative feedback and noise cancelling is presented. The proposed low noise amplifier consists of a positive transformer feedback to achieve noise-reduction and a negative transformer feedback to obtain high reverse isolation and stability. The noise cancellation technique is applied in this LNA to achieve a low noise figure. This LNA has been fabricated by standard commercial 90 nm CMOS. According to measurements, this proposed LNA achieves a peak gain of 11.5 d B, a noise figure of 6.5 d B and an input P1 d B of-12 d Bm. It consumes 11.5 m A from a1.2 V supply occupying the area of 0.6×0.7 mm2.

关键词： CMOS low noise amplifier Q-band transformer feedback noise cancelling millimeter wave

Influence of indoor airflow on airborne disease transmission in a classroom

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Building Simulation 2024年第3期17卷 355-370页

作者： Mojtaba Zabihi Ri li joshua Brinkerhoff School of Engineering Faculty of Applied ScienceUniversity of British ColumbiaKelownaCanada

It has been widely accepted that the most effective way to mitigate airborne disease transmission in an indoor space is to increase the ventilation airflow,measured in air change per hour(ACH).However,increasing ACH did not effectively prevent the spread of *** better understand the role of ACH and airflow large-scale patterns,a comprehensive fully transient computational fluid dynamics(CFD)simulation of two-phase flows based on a discrete phase model(DPM)was performed in a university classroom setting with people *** investigations encompass various particle sizes,ventilation layouts,and flow *** findings demonstrated that the particle size threshold at which particles are deemed airborne is highly influenced by the background flow strength and large-scale flow pattern,ranging from 5µm to 10µm in the cases *** effects of occupants are significant and must be precisely accounted for in respiratory particle transport *** enhanced ventilation design(UFAD-CDR)for university classrooms is introduced that places a premium on mitigating airborne disease *** to the baseline design at the same ACH,this design successfully reduced the maximum number density of respiratory particles by up to 85%.A novel airflow-related parameter,Horizontality,is introduced to quantify and connect the large-scale airflow pattern with indoor aerosol *** underscores that ACH alone cannot ensure or regulate air *** addition to the necessary ACH for air exchange,minimizing horizontal bulk motion is essential for reducing aerosol transmissibility within the room.

关键词： aerosol transmission airflow pattern horizontality COVID-19 simulation classroom ventilation

Data envelopment analysis for highway asset investment assessment

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第1期8卷 117-128页

作者： joshua Qiang li Sue McNeil School of Civil and Environmental Engineering Oklahoma State UniversityStillwaterOK 74078USA Department of Civil and Environmental Engineering University of DelawareNewarkDE 19702USA

Highway agencies have been using many of the elements of asset management with the support of various decision-making *** determine the most effective investment strategy with scarce resources,the integration,and hence better utilization,of existing tools and practices across asset classes is generally *** paper applies data envelopment analysis(DEA)to benchmark different highway investment scenarios using existing data or data readily available through existing *** asset types,pavements,bridges,and traffic signage,are *** investment analysis results from the Highway Economic Requirements System State Version(HERS-ST)application,the PONTIS bridge management system software,and purpose-built traffic signage spreadsheet are obtained to capture the changes of performance measures under various budget scenarios and are further used as the inputs for the DEA process to benchmark investment scenarios for each individual ***,the performance measures and budget levels are assembled in the Asset Manager-NT software,whose results are input into DEA to benchmark cross-assets resource allocation *** for the management of highway network is addressed via case studies in a systematic manner that recognizes the tradeoffs among different funding periods and objectives such as preserving existing investments,safety,roughness and user *** study has established a preliminary implementable framework of highway asset management by linking DEA approach and current widely used decision-making tools for more efficient investments within and cross assets,and better understand of the tradeoffs,costs and consequences of various asset management decisions.

关键词： Highway asset management Resource allocation Data envelopment analysis(DEA) Decision-making tools

Mapping the spatial distribution of fossil geothermal manifestations and assessment of geothermal potential of the Tangyin rift,Southeast of Taihang Mountain in China

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Journal of Mountain Science 2022年第8期19卷 2241-2259页

作者： MAHWA joshua li Da-jiang PING Jian-hua leNG wei TANG Jia-bo SHAO Dong-yun School of Water Conservancy and Engineering Zhengzhou UniversityZhengzhou 450001China Department of Geology College of Earth ScienceUniversity of DodomaBox 11090DodomaTanzania Power China Henan Engineering CO. LTDNo.30 Changchun RoadHigh and New Technology Industries Development ZoneZhengzhou450001China Geothermal and Ecological Geology Research Centre Zhengzhou UniversityZhengzhou 450001China College of Ecology and Environment Zhengzhou UniversityZhengzhou 450001China Power China Geothermal Development CO. LTDNo.30 Changchun RoadHigh and New Technology Industries Development ZoneZhengzhou450001China

The spatial prediction of geothermal sites along the southeast side of Taihang Mountain in the Tangyin rift is a critical goal in the development of renewable energy resources in cities such as Hebi in Henan province,which has significant potential for geothermal energy production due to the existence of deep faults and Cenozoic *** study aimed to delineate areas with high geothermal manifestations for detailed geothermal exploration and well-test *** define favorable zones for geothermal potentiality,multi-source datasets were chosen to generate evidence thematic layers that demonstrate the distribution of geothermal anomalies such as geologic maps,structural maps,Land Surface Temperature maps(LST),and hydrothermal mineral alterations *** remote sensing and Geographical Information System(GIS)approaches were integrated to map fossil geothermal manifestations and appraise the promising geothermal zones from Landsat 8 Oli/TIRS and Advanced Spaceborne Thermal Emission and Reflection Radiometer-Digital Elevation Model(ASTER-DEM)dataset using the Analytic Hierarchy Process(AHP),which is one of the Mult-criteria Decision Making *** show LST values ranging from 22.6℃ to 45.4℃,with the highest values found along the faults and volcanic *** hydrothermal alteration minerals discriminated from band ratios of 4/2,6/5,and 6/7 for iron oxide,ferrous minerals,and clays reveal the presence of high amount of montmorillonite and illite minerals along the faults and volcanoes which are related to hot fluid circulation from *** analysis shows that the major structural trend follows the NNE Tangdong and Tangxi faults,with high density on the west side of the Tangxi fault where there is good exposure of outcrop but less fault density on the east side due to sedimentation in a low land which may conceal geological ***,all the thematic layers of geothermal factors were reclassified,ranked,and integrated by the weight o

关键词： Geothermal potential Remote Sensing GIS Geological structures Alteration minerals Land surface temperature

Democratizing photogrammetry:an accuracy perspective

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Geo-Spatial Information Science 2023年第2期26卷 175-188页

作者： Jie Shan Zhixin li Damon lercel Kevan Tissue Joseph Hupy joshua Carpenter School of Civil Engineering Purdue UniversityWest LafayetteINUSA School of Aviation and Transportation Technology Purdue UniversityWest LafayetteINUSA

Photogrammetry is experiencing an era of democratization mostly due to the popularity and availability of many commercial off-the-shelf devices,such as drones and *** are used as the most convenient and effective tools for high-resolution image acquisition for a wide range of applications in science,engineering,management,and cultural ***,the quality,particularly the geometric accuracy,of the outcomes from such consumer sensors is still ***,the expected quality under different control schemes has yet to be thoroughly *** paper intends to answer those questions with a comprehensive comparative ***,in particular,structure from motion,has been used to reconstruct a 3D building model from smartphone and consumer drone images,as well as from professional drone images,all under various ground control *** from this study show that the positioning accuracy of smartphone images under direct geo-referencing is 165.4 cm,however,this could be improved to 43.3 cm and 14.5 cm when introducing aerial lidar data and total station surveys as ground control,*** results are found for consumer drone images as *** comparison,this study shows the use of the professional drone is able to achieve a positioning accuracy of 3.7 ***,we demonstrate that through the combined use of drone and smartphone images we are able to obtain full coverage of the entire target with a 2.3 cm positioning *** study concludes that smartphone images can achieve an accuracy equivalent to consumer drone images and can be used as the primary data source for building facade data collection.

关键词： Drone smartphone photogrammetry Structure from Motion(SfM) aero triangulation point clouds

Bacillus licheniformis PF9 improves barrier function and alleviates inflammatory responses against enterotoxigenic Escherichia coli F4 infection in the porcine intestinal epithelial cells

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Journal of Animal Science and Biotechnology 2022年第5期13卷 1413-1427页

作者： Qiao li linyan li Yanhong Chen Changning Yu Paula Azevedo joshua Gong Chengbo Yang College of Veterinary Medicine Nanjing Agricultural UniversityNanjing 210095China Department of Animal Science University of ManitobaWinnipegManitoba R3T 2N2Canada Guelph Research and Development Centre Agriculture Agri-Food CanadaGuelphOntario N1G 5C9Canada State Key Laboratory of Food Science and Technology Nanchang UniversityNanchang 330047China

Background:Enterotoxigenic Escherichia coli(ETEC)F4 commonly colonizes the small intestine and releases enterotoxins that impair the intestinal barrier function and trigger inflammatory *** Bacillus licheniformis(***)has been reported to enhance intestinal health,it remains to be seen whether there is a functional role of *** in intestinal inflammatory response in intestinal porcine epithelial cell line(IPEC-J2)when stimulated with ETEC ***:In the present study,the effects of *** PF9 on the release of pro-inflammation cytokines,cell integrity and nuclear factor-κB(NF-κB)activation were evaluated in ETEC F4-induced IPEC-J2 ***:*** PF9 treatment was capable of remarkably attenuating the expression levels of inflammation cytokines tumor necrosis factor-α(TNF-α),interleukin(IL)-8,and IL-6 during ETEC F4 ***,the gene expression of Toll-like receptor 4(TLR4)-mediated upstream related genes of NF-κB signaling pathway has been significantly *** changes were accompanied by significantly decreased phosphorylation of p65 NF-κB during ETEC F4 infection with *** PF9 *** immunofluorescence and western blotting analysis revealed that *** PF9 increased the expression levels of zona occludens 1(ZO-1)and occludin(OCLN)in ETEC F4-infected IPEC-J2 ***,the *** PF9 could alleviate the injury of epithelial barrier function assessed by the trans-epithelial electrical resistance(TEER)and cell permeability ***,*** PF9 protect IPEC-J2 cells against ETEC F4 infection by decreasing the gene expressions of virulence-related factors(including luxS,estA,estB,and elt)in ETEC ***:Collectively,our results suggest that *** PF9 might reduce inflammation-related cytokines through blocking the NF-κB signaling ***,*** PF9 displayed a significant role in the enhancem

关键词： Bacillus licheniformis PF9 Barrier function ETEC F4 Inflammatory response IPEC-J2

Artificial neural networks based on memristive devices

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Science China(Information Sciences) 2018年第6期61卷 145-158页

作者： Vignesh RAVICHANDRAN Can li Ali BANAGOZAR J.joshua YANG Qiangfei XIA Department of Electrical and Computer Engineering University of Massachusetts

The advent of memristive devices and the continuing research and development in the field of neuromorphic computing show great potential as an alternative to traditional von Neumann computing and bring us ever closer to realizing a true "thinking machine". Novel neural network architectures and algorithms inspired by the brain are becoming more and more attractive to keep up with computing needs,relying on intrinsic parallelism and reduced power consumption to outperform more conventional computing methods. This article provides an overview of various neural networks with an emphasis on networks based on memristive emerging devices, with the advantages of memristor neural networks compared with pure complementary metal oxide semiconductor(CMOS) implementations. A general description of neural networks is presented, followed by a survey of prominent CMOS networks, and finally networks implemented using emerging memristive devices are discussed, along with the motivation for developing memristor based networks and the computational potential these networks possess.

关键词： neuromorphic computing memristors neural networks