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Spatial dependence of high energy electrons and their radiations in pulsar wind nebulae

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Research in Astronomy and Astrophysics 2016年第6期16卷 47-58页

作者： Fang-Wu Lu quan-gui Gao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan University Department of Physics Yuxi Normal University

We investigate the spatial dependence of high energy electrons and their radiations in pulsar wind nebulae （PWNe）. By assuming a time-dependent broken power-law injection and spatial dependence of convection velocity, magnetic field strength and diffusion coefficient on the radial distance of an expand- ing system, we numerically solve the Fokker-Planck transport equation including convection, diffusion, adiabatic loss and radiative loss in spherical coordinates, and investigate the effects of magnetic field, PWN age, maximum energy of electrons, and diffusion coefficient on electron spectra and non-thermal photon emissions. Our results indicate that （1） electron spectra and the corresponding photon spectra are a function of radial distance r of the expanding system; （2） for a given expansion velocity, the increase of the PWN age causes a slower decrease of the convection velocity （V ∝ r-β） and a more rapid decrease of the magnetic field strength （B ∝ r-1＋β）, but a more rapid increase of the diffusion coefficient （k∝ r1-β） because the index β decreases with the PWN age; and （3） the lower energy part of the electron spectra is dominated by convection and adiabatic loss, but the higher energy part is dominated by the competition between syn- chrotron loss and diffusion, and such a competition is a function of radial distance. Therefore the diffusion effect has an important role in the evolution of electron spectra as well as non-thermal photon spectra in a PWN.

关键词： diffusion -- ISM: supernova remnants -- pulsars: general -- radiation mechanisms: non-thermal

CNN-Based Intelligent Safety Surveillance in Green IoT Applications

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China Communications 2021年第1期18卷 108-119页

作者： Wengang Cao Jianing Zhang Changxin Cai quan chen Yu Zhao Yimo Lou Wei Jiang Guan gui College of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Electronic and Information Yangtze UniversityJingzhou 434023China

Safety surveillance is considered one of the most important factors in many constructing industries for green internet of things(IoT)***,traditional safety monitoring methods require a lot of labor *** this paper,we propose intelligent safety surveillance(ISS)method using a convolutional neural network(CNN),which is an autosupervised method to detect workers whether or not wearing ***,to train the CNN-based ISS model,the labeled datasets mainly come from two aspects:1)our labeled datasets with the full labeled on both helmet and pedestrian;2)public labeled datasets with the parts labeled either on the helmet or *** fully take advantage of all datasets,we redesign CNN structure of network and loss functions based on ***,we test our proposed ISS method based on the specific detection evaluation ***,experimental results are given to show that our proposed ISS method enables the model to fully learn the labeled information from all *** the threshold of intersection over union(IoU)between the predicted box and ground truth is set to 0.5,the average precision of pedestrians and helmets can reach 0.864 and 0.891,respectively.

关键词： convolutional neural network(CNN) internet of things(IoT) intelligent safety surveillance deep learning auto-supervised method

Acute Complication Prediction and Diagnosis Model CLSTM-BPR:A Fusion Method of Time Series Deep Learning and Bayesian Personalized Ranking

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Tsinghua Science and Technology 2024年第5期29卷 1509-1523页

作者： Xi chen quan cheng School of Economics and Management Fuzhou UniversityFuzhou 350108China

Acute complication prediction model is of great importance for the overall reduction of premature death in chronic *** CLSTM-BPR proposed in this paper aims to improve the accuracy,interpretability,and generalizability of the existing disease prediction ***,through its complex neural network structure,CLSTM-BPR considers both disease commonality and patient characteristics in the prediction ***,by splicing the time series prediction algorithm and classifier,the judgment basis is given along with the prediction ***,this model introduces the pairwise algorithm Bayesian Personalized Ranking(BPR)into the medical field for the first time,and achieves a good result in the diagnosis of six acute *** on the Medical Information Mart for Intensive Care IV(MIMIC-IV)dataset show that the average Mean Absolute Error(MAE)of biomarker value prediction of the CLSTM-BPR model is 0.26,and the average accuracy(ACC)of the CLSTM-BPR model for acute complication diagnosis is 92.5%.Comparison experiments and ablation experiments further demonstrate the reliability of CLSTM-BPR in the prediction of acute complication,which is an advancement of current disease prediction tools.

关键词： Long Short-Term Memory(LSTM) Bayesian Personalized Ranking(BPR) sudden illnesses disease predictions

Feasibility of measuring moisture content of green sand by a low frequency multiprobe detector based on dielectric characteristics

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China Foundry 2023年第3期20卷 197-206页

作者： De-quan Shi gui-li Gao Ming Sun Ya-xin Huang School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics and InformationShanghai 201411China School of Materials Science&Chemical Engineering Harbin University of Science and TechnologyHarbin 150040China

Green sand is a mixture of silica sand,bentonite,water and coal powder,and other *** content is an important index to characterize the properties of green *** on the dielectric characteristics of green sand and transmission line theory,a method for rapidly measuring the moisture content of green sand by means of a low frequency multiprobe detector was proposed.A system was constructed,where six detectors with different arrangements and probes were *** experimental results showed that the voltage difference of transmission line increases with the increasing frequency before 29 MHz while decreases after 35 MHz.A voltage difference platform occurs in the range of 29-35 MHz,which is suitable for measuring the moisture content due to its insensitivity to *** electric field intensity gradually decreases with the increase of the probe depth,and the intensity of central probe is always greater than that of the edge *** the distance of the probe away from the sand sample surface is 80 mm,the electric field intensity of the edge probe is found to be very *** optimal excitation frequency for measuring the moisture content of green sand is 29-33 *** optimal detector is the one with one center probe and three edge probes,and their lengths are 80 mm and 60 mm,*** distance between the center and edge probes is 25 mm,and the diameter of probes is 5 *** the voltage difference of transmission line,bentonite content,coal powder content and compactability as parameters of the input layer,and the moisture content as a parameter of the output layer,a three-layer BP artificial neural network model for predicting the moisture content of green sand was constructed according to the experimental results at 33 *** prediction error of the model is not higher than 3.3% when the moisture content of green sand is within the range of 3wt.%-7wt.%.

关键词： green sand dielectric property moisture content multiprobe detector BP artificial neural network model

Shear-induced Precursors of Fibrillar Crystals of Poly(butene-1):A Rheological Study

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Chinese Journal of Polymer Science 2022年第6期40卷 618-623页

作者： Jia-Qi Zhang quan chen State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China

Strong preshear flow stretches poly(butene-1)chains to form flow-induced precursors of fibrillar *** formation leads to further growth of shear/normal stress after the stress reaches the steady *** this study,stress relaxation measurements are performed after intervals of a strong flow during which the precursors *** small-angle X-ray scattering(SAXS)and wide-angle X-ray diffraction(WAXD)measurements are conducted to characterize the crystalline structure formed after the preshear and relaxation processes,each of different periods.A combination of the stress relaxation and scattering results reveal that for the precursors formed within 5 s,the stress can fully relax and the orientation of the subsequent crystals(formed upon quenching the sample at different stress levels)decays gradually with the *** comparison,for those precursors formed after 5 s,the stress hardly relaxes during~10^(4) s,and the orientation of the subsequent crystals hardly decays,suggesting that the precursors have been somehow stabilized during the *** features have been discussed with respect to the percolation of the precursors to form a reversible network.

关键词： PB-1 Rheology Precursor Fibrillar crystal

Growth and Cd Accumulation of Orychophragmus violaceus as Affected by Inoculation of Cd-Tolerant Bacterial Strains

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Pedosphere 2014年第3期24卷 322-329页

作者： LIANG Xia HE Chi-quan NI Gang TANG gui-E chen Xue-Ping LEI Yan-Ru School of Environmental and Chemical Engineering Shanghai University

Beneficial interactions between microorganisms and plants, particularly in the rhizosphere, are a research area of global interest. Four cadmium(Cd)-tolerant bacterial strains were isolated from heavy metal-contaminated sludge and their effects on Cd mobility in soil and the root elongation and Cd accumulation of Orychophragmus violaceus were explored to identify the capability of metalresistant rhizobacteria for promoting the growth of O. violaceus roots on Cd-contaminated soils. The isolated strains, namely, Bacillus subtilis, B. cereus, B. megaterium, and Pseudomonas aeruginosa, significantly enhanced the plant Cd accumulation. The Cd concentrations in the roots and shoots were increased by up to 2.29- and 2.86-fold, respectively, by inoculation of B. megaterium, as compared with the uninoculated control. The bacterial strains displayed different effects on the shoot biomass. Compared with the uninoculated plants, the shoot biomass of the inoculated plants was slightly increased by B. megaterium and significantly decreased by the other strains. B. megaterium was identified as the best candidate for enhancing Cd accumulation in O. violaceus. Thus, this study provides novel insight into the development of plant-microbe systems for phytoremediation.

关键词： heavy metals phytoremediation plant-microbe systems rhizobacteria soil contamination

Low-temperature densification sintering and properties of CaAl_2Si_2O_8 ceramics with MeO·2B_2O_3(Me=Ca,Sr,Ba)

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 977-986页

作者： Song chen De-gui Zhu School of Materials Science and Engineering Southwest Jiaotong University

Dense CaAl2Si2O8 ceramics were prepared via a two-step sintering process at temperatures below 1000℃. First, pre-sintered CaAl2Si2O8 powders containing small amounts of other crystal phases were obtained by sintering a mixture of calcium hydroxide and kaolin powders at 950℃ for 6 h. Subsequently, the combination of the pre-sintered ceramic powders with MeO＇2B203 （Me = Ca, Sr, Ba） flux agents enabled the low-temperature densification sintering of the CaAl2Si2O8 ceramics at 950℃. The sintering behavior and phase formation of the CaAl2Si2O8 ceramics were investigated in terms of the addition of the three MeO·2B2O3 flux agents. Furthermore, alumina and quartz were introduced into the three flux agents to investigate the sintering behaviors, phase evolvements, microstructures, and physical properties of the resulting CaA12Si208 ceramics. The results showed that, because of their low-melting characteristics, the MeO·2B2O3 （Me = Ca, Sr, Ba） flux agents facilitated the formation of the CaAl2Si2O8 ceramics with a dense microstructure via liquid-phase sintering. The addition of alumina and quartz to the flux agents also strongly affected the microstructures, phase formation, and physical properties of the CaA12Si208 ceramics.

关键词： ceramics densification sintering materials properties anorthite borates alumina quartz

Influence of sintering temperature on the phases and photoelectric characteristics of BiOCl/ZnO composite powders

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1438-1447页

作者： Song chen De-gui Zhu School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

Zinc oxide is a typical functional oxide that has been widely researched for various industry applications due to its peculiar physical characteristics. However, to achieve its potential in promising applications, much work has been diligently performed to improve the physical properties of ZnO. In this work, an aqueous suspension route was used to prepare BiOCl/ZnO composite powders, and sintering processes were applied to investigate the influence of sintering temperature on the phase evolutions, microstructures, and photoelectric characteristics of BiOCl/ZnO composite powders. The results indicated that the photoelectric properties mainly depend on the relevant content of BiOCl in the composite powders and the sintering temperature. The photoelectric measurements in K_2SO_4 solutions show that the photoelectric properties of the samples with the appropriate BiOCl content(0.3 mol% and 2.0 mol%) are better than those of ZnO and commercial TiO_2(P_(25)) powders, but the photoelectric measurements in NaOH solutions indicate that the photoelectric characteristics of the as-sintered samples are only better than those of P_(25).

关键词： ZnO/BiOCl composites sintering temperature microstructures photoelectric characteristics

Autologous tenon capsule packing to treat posterior exit wound of penetrating injury: A case report

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World Journal of Clinical Cases 2021年第19期9卷 5211-5216页

作者： quan-Yong Yi Sang-Sang Wang Qian gui Li-Shuang chen Wen-Die Li Department of Ophthalmology Ningbo Eye HospitalNingbo 315040Zhejiang ProvinceChina

BACKGROUND This study reports a case of autologous tenon capsule packing to treat the posterior exit wound of penetrating *** SUMMARY To treat a 58-year-old male patient with penetrating eyeball injury caused by an iron sheet,we used autologous tenon capsule *** months after removal of the silicone oil,the corrected visual acuity was 0.3,the retina was flat,the tenon capsule graft was in place,the posterior wound closed well,and the intraocular pressure was 15.8 *** Autologous tenon capsule packing to treat the posterior exit wound of penetrating injury is safe and effective.

关键词： Autologous Penetrating injury Case report