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Near-field magnetic induction communication device for underground wireless communication networks

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Science China(Information Sciences) 2014年第12期57卷 157-167页

作者： MA Jing zhang xiaotong HUANG QiWei School of Computer and Communication Engineering University of Science and Technology Beijing

Electromagnetic(EM)waves are the most versatile and widely adopted physical layer technology for underground wireless communication networks(UWCNs).However,they are not suitable for underground communication especially when coils are buried in ***-inductive(MI)communication is a promising technique for UWCNs;it is not affected by large propagation delays,multipath propagation,and ***,MI communication has lower transmitting power and smaller antenna size than EM.A near-field low-power communication device with an electrically small antenna for low-frequency UWCNs is proposed in this *** device can be easily buried *** proposed device is analyzed in terms of basic communication metrics,i.e.,magnetic field intensity,bandwidth,path losses,and received *** of these four metrics shows that the experimental data closely match those of the theoretical model,and the maximum communication distance of 28.5 m,can be ***,according to the experimental results of our device,we further propose the modified received power *** show that the device exhibits good performance and can be used as a stand-alone module in directional underground wireless communication.

关键词： magnetic induction low power electrically small antenna underground wireless communication received power model

A direct bonding copper degradation monitoring method for insulated gate bipolar transistor modules: Boundary‐dependent thermal network combined with feedback control

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High Voltage 2023年第6期8卷 1264-1274页

作者： xiaotong zhang Zhuolin Cheng Xing Sun Kangning Wu Jianying Li State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina

The direct bonding copper(DBC)substrates of insulated gate bipolar transistor(IGBT)modules degrade inevitably under cycling thermo‐mechanical stress,causing potential threat to the reliability of IGBT ***,little attention has been paid to monitoring their *** paper proposes a DBC degradation monitoring method for IGBT modules,which combines boundary‐dependent thermal network and feedback control.A thermal network is employed to describe the internal material degradation of IGBT modules and can be extracted from a finite‐element method *** boundary conditions including power losses and DBC degradation are considered,enabling the thermal network suitable for various working conditions and different DBC degradation conditions of IGBT *** DBC degradation is characterised by its equivalent thermal conductivities measured in the thermal cycling ageing *** the basis of the boundary‐dependent thermal network,feedback control is applied to monitor DBC degradation by regulating boundary‐dependent thermal ***,the proposed model is verified from the effectiveness and accuracy of DBC degradation monitoring and junction temperature *** method casts new light on thermal network modelling and could provide a feasible method for the monitoring of DBC degradation.

关键词： network bipolar transistor

Effect of astragaloside Ⅳ on the immunoregulatory function of adipose-derived mesenchymal stem cells from patients with psoriasis vulgaris

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Journal of Traditional Chinese Medicine 2022年第4期42卷 513-519页

作者： YIN Xiuping zhang xiaotong ZHU Rongjia SONG Ping Department of Dermatology Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China Beijing Key Laboratory of New Drug Development and Clinical Trial of Stem Cell Therapy(BZ0381)/Center of Excellence in Tissue Engineering Institute of Basic Medical Sciences CAMSSchool of Basic Medicine PUMCBeijing 100005China

OBJECTⅣE:To compare the phenotype and adipogenic and osteogenic differentiation capacities of adiposederived mesenchymal stem cells(AMSCs)isolated from patients with psoriasis vulgaris and healthy donors,and to explore the effects of astragalosideⅣ,a Traditional Chinese Medicine,on the immunoregulatory function of ***:AMSCs were isolated from human adipose tissue and cultured for three generations in *** phenotype and cell cycle analysis were performed by flow *** and osteogenic differentiation of AMSCs was examined by lipid(oil red O)and alkaline phosphatase staining,*** of inflammatory mediators was examined by real-time quantitative polymerase chain reaction analysis,and proliferation was quantified using the cell counting kit-8 ***:Expression of CD29,CD44,and CD73 was higher in AMSCs from healthy donors than psoriasis patients,while the reverse was true for expression of CD45,CD31,and *** from psoriasis patients had a greater ability to undergo adipogenic differentiation than cells from healthy donors,whereas there was no significant difference in osteogenic differentiation between AMSCs from the two *** with AMSCs from healthy donors,psoriasis patient-derived AMSCs expressed lower levels of the anti-inflammatory cytokines interleukin-10 and transforming growth factor-β(TGF-β)and the immune checkpoint ligand programmed cell death 1 ligand 1(PDL1)(P<0.05)and higher levels of the pro-inflammatory cytokines tumor necrosis factor-α(TNF-α)and interferon-γ(IFN-γ).Incubation of AMSCs from psoriasis patients with astragalosideⅣhad no significant effect on proliferation but increased the expression of TGF-βand PDL1 and decreased the expression of IFN-γand TNF-α.CONCLUSION:AMSCs from patients with psoriasis vulgaris display abnormal proliferation and adipogenesis and an enhanced pro-inflammatory *** defects were normalized by treatment with astragalosideⅣ,suggesting that this

关键词： psoriasis mesenchymal stem cells cell proliferation astragalosideⅣ adipogenesis osteogenesis immune regulation

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Evaluation and intercomparison of multiple satellite-derived and reanalysis downward shortwave radiation products in China

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International Journal of Digital Earth 2023年第1期16卷 1853-1884页

作者： Liu Tong Tao He Yichuan Ma xiaotong zhang Hubei Key Laboratory of Quantitative Remote Sensing of Land and Atmosphere School of Remote Sensing and Information EngineeringWuhan UniversityWuhanPeople’s Republic of China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityPeople’s Republic of China State Key Laboratory of Remote Sensing Science Faculty of Geographical ScienceBeijing Normal UniversityBeijingPeople’s Republic of China Beijing Engineering Research Center for Global Land Remote Sensing Products Institute of Remote SensingScience and EngineeringFaculty of Geographical ScienceBeijing Normal UniversityBeijingPeople’s Republic of China

Downward shortwave radiation(DSR)is a critical variable in energy balance driving Earth’s surface ***-derived and reanalysis DSR products have been developed and continuously improved during the last ***,as those products have different temporal resolutions,their performances in different time scales have not been well-documented,particularly in *** study intended to evaluate several DSR products across multiple time scales(***,1-hourly,daily,and monthly average)and ecosystems in *** DSR products,including GLASS,BESS,CLARA-A2,MCD18A1,ERA5 and MERRA-2,were evaluated against ground measurements at Chinese Ecosystem Research Network(CERN)and integrated land-atmosphere interaction observation(TPDC)sites from 2009 to *** instantaneous DSR of MCD18 showed a root mean square error(RMSE)of 146.02 W/m^(2).The hourly RMSE of ERA5(155.52 W/m^(2))was largely smaller than MERRA-2(188.53 W/m^(2)).On the daily and monthly scale,BESS had the most optimized accuracy among the six products(RMSE of 36.82 W/m^(2)).For the satellite-derived DSR products,the monthly accuracy at CERN can meet the threshold accuracy requirement set by World Meteorological Organization(WMO)for Global Numerical Weather Prediction(20 W/m^(2)).

关键词： Downward shortwave radiation product validation remote sensing products reanalysis products

An In-Situ MRI Method for Quantifying Temperature Changes during Crystal Hydrate Growths in Porous Medium

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Journal of Thermal Science 2022年第5期31卷 1542-1550页

作者： zhang Lunxiang SUN Mingrui WANG Tian YANG Lei zhang xiaotong ZHAO Jiafei SONG Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power EngineeringDalian University of TechnologyDalian116024China Interdisciplinary Institute of Neuroscience and Technology Zhejiang UniversityHangzhou310029China

Given the complexity of the thermo-hydro-chemically coupled phase transition process of hydrates,real-time in-situ observations are *** maps are particularly essential in analyzing the heat transfer process during the growth and dissociation of crystal *** this study,we present the temporally and spatially resolved thermometry of the formation of tetrahydrofuran hydrates based on the temperature dependence of the chemical shift of the water *** of temperature changes were synchronously obtained using a 9.4 T^(1)H magnetic resonance imaging(MRI)system to predict the saturation level of the aqueous solution,phases of the solid hydrates,and the positive temperature anomaly of the exothermic *** was observed that variations in the MRI signal decreased while the temperature rise differed significantly in space and *** results predicted in this study could have significant implications in optimizing the phase transition process of gas hydrates.

关键词： hydrate phase transition heat transfer porous medium temperature mapping magnetic resonance imaging thermometry thermodynamics and molecular-scale phenomena

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Key issues and algorithms of multiple-input-multiple-output over-the-air testing in the multi-probe anechoic chamber setup

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Science China(Information Sciences) 2022年第3期65卷 51-77页

作者： Huiling PEI Xiaoming CHEN Xiaoyu HUANG Xiaobo LIU xiaotong zhang Yi HUANG School of Information and Communications Engineering Xi'an Jiaotong University College of Electrical Engineering Zhejiang University Interdisciplinary Institute of Neuroscience and Technology Zhejiang University Department of Electrical Engineering and Electronics University of Liverpool

Multiple-input-multiple-output(MIMO) over-the-air(OTA) testing plays a key role in the research and development of wireless devices. MIMO OTA testing is necessary for the fifth generation(5 G)wireless products, in which conventional radio frequency ports may be inaccessible. The performances of the test device can be evaluated in a repeatable and reliable way under laboratory conditions in OTA tests,which might not be feasible in conducted tests. Many efforts have been devoted to OTA test research and some achievements have been made. This paper mainly summarizes the channel emulation algorithms for two-dimensional user equipment and three-dimensional base station OTA testing in the anechoic chamber setup. In addition, the requirements of the test system design are also discussed in this paper, including the selection of the number of OTA probes, the size of the test zone, the physical dimension of the setup, and the flexible probe selection algorithm of the three-dimensional base station OTA setup. In addition, some novel test methods for 5 G radio devices are also discussed.

关键词： MIMO OTA testing multi-probe anechoic chamber 5G spatial channel

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In-Fiber Thermally Diffused Coupler and Fiber Bragg Grating Inscribed in Twin-Core Fiber for Sensitivity-Enhanced Vector Bending Sensing

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Photonic Sensors 2023年第3期13卷 63-76页

作者： Lingzhi MENG Hongye WANG Qi XIA Tingting YUAN xiaotong zhang Libo YUAN The Key Lab of In-Fiber Integrated Optics Ministry Education of ChinaHarbin Engineering UniversityHarbin 150001China The Center for Smart Sensing System Julong CollegeShenzhen Technology UniversityShenzhen 518118China Photonics Research Center School of Optoelectronic EngineeringGuilin University of Electronic TechnologyGuilin 541004China

A vector bending fiber sensor based on core-by-core inscribed fiber Bragg gratings in a twin-core fiber has been proposed and experimentally *** in-fiber integrated vector bending sensor is realized by using the thermal diffusion technique to fabricate the *** characteristics of the coupler fabricated by thermal diffusion are simulated and *** inscribing fiber Bragg gratings with different reflection wavelengths in the two cores of a symmetrical twin-core fiber,the curvature sensitivity can be enhanced by tracking the wavelength difference between the fiber Bragg gratings of the two *** measured bending sensitivity of the fiber Bragg grating ranges from–161.6 pm/m^(−1) to+165.5 pm/m^(−1).The differential sensitivity of the two cores is twice that of a conventional single grating,and the temperature-induced crosstalk is also *** bending sensor proposed in this paper has the advantages of high integration,enhancing the sensitivity and two-dimensional orientation recognizability,and reducing temperature crosstalk,which can be a promising candidate for structural health monitoring or wearable artificial electronics applications.

关键词： Digital holographic tomography thermal diffusion bending sensing

Spatiotemporal evolution of sustainable development of China’s provinces:a modelling approach

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Ecosystem Health and Sustainability 2021年第1期7卷 354-371页

作者： Junli Gao Chaofeng Shao Sihan Chen xiaotong zhang College of Environmental Science and Engineering Nankai UniversityTianjinChina China National Engineering Research Center for Human Settlements BeijingChina

Three sustainable development sub-indicators were established along with 49 indicators of sustainable development at the provincial *** collected data for the key years of 2010,2015,and 2018 and evaluated the sustainable development level of 31 provinces in China by using the best and worst value improved equal-weight TOPSIS *** spatial autocorrelation and hotspot analysis,the spatial characteristics of the sustainable development level were *** correlation analysis and the offset degree index were also used to find out which indicators should be of most concern to improve the level of sustainable *** results showed the following.(1)The level of sustainable development of China’s provinces is increasing,but there is a decrease from east to west.(2)In terms of sustainable development,the gap between the four major economic regions is narrowing.(3)The overall sustainable development level is highly consistent with the mainstream green development and the human development index,indicating that exploiting the driving force behind developing and improving the quality of development is the key to China’s sustainable development strategy.(4)Different measures should be taken to promote the realization of Sustainable Development Goals in different areas.

关键词： Sustainable development goals SDG localization sustainable development index spatial-temporal analysis

Leaching behavior of phosphorous compounds from sewage sludge ash based on quantitative X-ray diffraction analysis

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Waste Disposal and Sustainable Energy 2020年第2期2卷 113-125页

作者： Pinjing He xiaotong zhang Fan Lü Liming Shao Hua zhang Institute of Waste Treatment and Reclamation College of Environmental Science and EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Pollution Control and Resource Reuse Tongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Phosphorus(P)is an essential and limited *** sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching ***,the recovery ratio depends on the speciation of P and the leaching *** this study,hydrochloric acid was used as a leaching agent,and the effects of the hydrochloric acid concentration,leaching time,temperature,and liquid-solid ratio on the P leaching ratio were ***,the co-leaching of macro-metals Ca,Al,Fe,and Mg was *** results showed that P leached rapidly within 30 min,where the leaching rate reached more than 80%and then gradually *** leaching concentrations of Ca and Mg had a significant correlation(correlation coefficient r^(2)>0.90),and both were leached *** and P had similar leaching patterns,where the leaching rates increased initially and then decreased with time at 0.2 mol/L *** to X-ray diffraction analysis and Rietveld refinement,the P in ISSA was mainly present in the forms of Mg_(3)Ca_(3)(PO_(4))_(4) and AlPO_(4).When leached using 0.2 mol/L HCl at 55℃ with a liquid-to-solid ratio of 20 L/kg,the AlPO_(4) and Fe_(3)(H_(2)O)_(3)(PO_(4))_(2) in ISSA dissolved initially and then precipitated on the surface of the solid phase,thereby impeding further P leaching.

关键词： Sewage sludge ash Acid leaching Phosphorous speciation Quantitative X-ray diffraction analysis Rietveld refinement