检索结果-南通市图书馆

Journal of Wuhan University of Technology(Materials Science) 2023年第5期38卷 1221-1230页

作者： yang ting JIANG Hongyi DONG Ye GAO Shuai LIU Shuning School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The low-valence cations Na^(+)and Sr^(2+)were selected as the co-dopants to increase the vacancies concentration in the Y_(2.982)Ce_(0.018)Al_(2)Ga_(3)O_(12)*** successful incorporation of Na^(+)and Sr^(2+)was confirmed by the X-Ray Difiraction(XRD)*** the samples show 5d-4f green persistent luminescence of Ce^(3+)after 450 nm *** decay curves demonstrate that the persistent luminescence is efiectively enhanced with Na+and Sr2+*** thermoluminescence glow curves also show not only does the trap concentration increase,but also the distribution of trap depths is *** addition,the air-and H_(2)/Ar-annealing treatments were conducted on every as-made *** experimental results prove that the increased traps after the Na^(+)/Sr^(2+)doping are mainly attributed to the oxygen vacancies,and the traps have a continuous and broad distribution of trap *** hope this work could give new inspiration for designing a high-performance persistent phosphor.

关键词： persistent luminescence YAGG Na^(+) Sr^(2+) oxygen vacancy charge compensation solidstate reaction

Variations and drivers of aerosol vertical characterization after clean air policy in China based on 7-years consecutive observations

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第3期125卷 499-512页

作者： Xi Chen ting yang Haibo Wang Futing Wang Zifa Wang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Understanding the aerosol vertical characterization is of great importance to both climate and atmospheric environment. This study investigated the variations of aerosol profiles over eight regions of interest in China after clean air policy(2013-2019) and discussed the drivers of the vertical aerosol structure, using observations from active satellite measurements(CALIPSO). From the annual variation, the amplitude of extinction coefficient profiles showed a decreasing trend with fluctuations, and the maximum was 0.21 km-1in BeijingTianjin-Hebei(JJJ). For regions suffered from air pollution, the variation was greatest below 0.45 km, while it was between 1-1.5 km for Sichuan Basin. The correlation coefficient between the relative humidity(RH) and the extinction coefficient indicated that the increase of RH inhibited the decrease of the extinction coefficient in the yangtze River Delta. In most regions, the main aerosol subtypes were polluted dust and polluted continental, but they were coarser in JJJ and North West. The frequency of concurrency of dust and polluted dust aerosols decreased in JJJ, but polluted continental aerosols occurred more frequently. Further, the aerosol extinction coefficient profiles under different pollution conditions showed that it changed most during heavy pollution periods in JJJ, especially in 2017, with a significant aerosol loading between700 and 1200 m. The atmospheric reanalysis data revealed that the weak convergence at low level and the divergence at high level supported the upward transport of aerosols in 2017. Overall, the differences in divergence allocation, RH, and wind filed were the main meteorological drivers.

关键词： Aerosol Vertical characteristic China CALIPSO Pollution period

Bipartite consensus of higher-order multi-agent systems based on event-triggered control and signed network

在线全文

学校读者我要写书评

暂无评论

Journal of Control and Decision 2021年第2期8卷 233-242页

作者： Mei Yu Wenyu He ting yang School of Control and Computer Engineering North China Electric Power UniversityBeijing102206People’s Republic of China

Consensus of higher-order multi-agent systems based on event-triggered control and signed network is studied in this paper,where signed multi-agent systems control protocol takes hostile relations into account between different ***-triggered protocol for the second-order signed multi-agent systems is *** results are obtained for high-order signed multiagent *** addition,for the two control strategies proposed in this paper,it is proved that Zeno behaviours do not ***,simulation examples are presented to verify the correctness of the results.

关键词： Multi-agent systems signed network higher-order event-triggered

Conditional limit theorems for critical continuous-state branching processes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2014年第12期57卷 2577-2588页

作者： REN YanXia yang ting ZHAO GuoHuan LMAM School of Mathematical Sciences Peking University Center for Statistical Science Peking University Academy of Mathematics and Systems Science Chinese Academy of Sciences

We study the conditional limit theorems for critical continuous-state branching processes with branching mechanism Ф（λ） = λ 1＋αL（1/λ）, where （α∈ [0, 1] and L is slowly varying at co. We prove that if α ∈ （0, 1], there are norming constants Qt →0 （as t ↑ ＋ ∞） such that for every x 〉 0, Px（QtXt ∈ · ｜Xt 〉 0） converges weakly to a non-degenerate limit. The converse assertion is also true provided the regularity of ψ at 0. We give a conditional limit theorem for the case α = 0. The limit theorems we obtain in this paper allow infinite variance of the branching process.

关键词： continuous-state branching process conditional laws regular variation

Traveling wave solutions for a diffusive three-species intraguild predation model

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2018年第2期11卷 147-173页

作者： Jian-Jhong Lin ting-Hui yang General Education Center National Taipei University of Technology Taipei 10608 Taiwan Department of Mathematics Tamkang University Tamsui Dist. New Taipei City 25137 Taiwan

The aim of this work is to investigate the existence and non-existence of traveling wave solutions for a diffusive three-species intraguild predation model which means that one predator can eat its potential resource competitors. The method of upper-lower solution is implemented to show the existence of traveling wave solutions. In order to simplify the construction of an admissible pair of upper lower solution, the scheme of strictly con- tracting rectangle is applied. Finally, the minimal speed c＊ of traveling wave solutions of the model is characterized. If the wave speed is greater than c＊, we show the exis- tence of traveling wave solutions connecting trivial and positive equilibria by combining the upper and lower solutions with the contracting rectangle. On the other hand, if the wave speed is less than c＊, the non-existence of such solutions is also established. Furthermore, to illustrate our theoretical results, some numerical simulations are performed and biological meanings are interpreted.

关键词： Three-species model intraguild predation traveling wave solutions contract-ing rectangle omnivory.

Roll profile electromagnetic control characteristics under roll heterogeneity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2022年第12期29卷 1927-1938页

作者： ting-song yang Yu-hang Bai yang Hai Qi-fa Chen Feng-shan Du National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina College of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

The electromagnetic control roll(ECR)and electromagnetic stick(ES)are the core elements and the main driving parts of roll profile electromagnetic control technology(RPECT).To prolong the service life,it is necessary to treat ECR and ES *** to the heterogeneous characteristics of surface treatments,the roll profile electromagnetic control characteristics were analyzed for different *** electromagnetic-thermal-force coupled axisymmetric finite element model was built to explore the differences in performance as a result of several treatment strategies,and the model was verified by experimental results measured with a roll profile electromagnetic control experimental *** model was used to analyze the influence of the heterogeneity of ECR inner hole and ES on the roll crown,the roll profile,the average contact pressure,and the stress state during RPECT *** results indicate that the heterogeneous layer at ECR inner hole has a restrictive effect on RPECT and that the heterogeneous layer of ES can enhance the profile control ability of RPECT.A reasonable configuration scheme between the heterogeneity of ECR inner hole and the ES can increase the life of ECR and maintain the control ability of RPECT.

关键词： Electromagnetic control roll Heterogeneous treatment Roll crown Roll profile electromagnetic control technology Electromagnetic stick

Fekete and Szego problem for a subclass of quasi-convex mappings in several complex variables

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2015年第6期10卷 1461-1472页

作者： Qinghua XU ting yang Taishun LIU Huiming XU College of Mathematics and Information Science Jiangxi Normal University Nanchang 330022 China Department of Mathematics Huzhou University Huzhou 313000 China College of Mathematics Physics and Information Engineering Zhejiang Normal UniversityJinhua 321004 China

Let K be the familiar class of normalized convex functions in the unit disk. Keogh and Merkes proved the well-known result that maxf∈A ｜a3 - λa22｜ ≤ max{1/3, ｜λ - 1}, ,λ ∈ C, and the estimate is sharp for each ∈. We investigate the corresponding problem for a subclass of quasi-convex mappings of type B defined on the unit ball in a complex Banach space or on the unit polydisk in Cn. The proofs of these results use some restrictive assumptions, which in the case of one complex variable are automatically satisfied.

关键词： Fekete-Szego problem quasi-convex mappings of type A quasi-convex mappings of type B quasi-convex mappings of type C

Reaction mechanism of dicofol removal by cellulase

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第10期27卷 22-28页

作者： Ziyuan Wang ting yang Zihan Zhai Boya Zhang Jianbo Zhang Collaborative Innovation Center for Regional Environmental Quality State Key Joint Laboratory of Environmental Simulation and Pollution ControlCollege of Environmental Science and EngineeringPeking University School of Public Health Peking University

It remains unclear whether dicofol should be defined as a persistent organic pollutant. Its environmental persistence has gained attention. This study focused on its degradation by cellulase. Cellulase was separated using a gel chromatogram, and its degradation activity towards dicofol involved its endoglucanase activity. By analyzing the kinetic parameters of cellulase reacting with mixed substrates, it was shown that cellulase reacted on dicofol and carboxyl methyl cellulose through two different active centers. Thus, the degradation of dicofol was shown to be an oxidative process by cellulase. Next, by comparing the impacts of tert-butyl alcohol（a typical OH free-radical inhibitor） on the removal efficiencies of dicofol under both cellulase and Fenton reagent systems, it was shown that the removal of dicofol was initiated by OH free radicals produced by cellulase. Finally, 4,4′-dichlorodibenzophenone and chloride were detected using gas chromatography mass spectrometry and ion chromatography analysis, which supported our hypothesis. The reaction mechanism was analyzed and involved an attack by OH free radicals at the orthocarbon of dicofol, resulting in the degradation product 4,4′-dichloro-dibenzophenone.

关键词： Dicofol Cellulase Endo-glucanases activity Oxidative degradation OH free radical

Wiener Filtration Algorithm of an Ensemble Pulsar Timescale Based on a Power-law Model of Pulsar Power Spectrum

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第10期22卷 129-140页

作者： ting-Gao yang Ming-Lei Tong Yu-Ping Gao National Time Service Center Chinese Academy of SciencesXi'an 710600China Key Laboratory of Time and Frequency Primary Standards Chinese Academy of SciencesXi'an 71000China University of Chinese Academy of Sciences Beijing 100049China

An ensemble pulsar timescale derived from the traditional Wiener filtration still contains some high level *** improve this situation we developed a Wiener filtration algorithm of the ensemble pulsar timescale based on a power-law model of power spectrum for *** algorithm has three strengths:(1)mitigating spectral leakage between frequency bins for Fourier techniques;(2)using a power-law model for power spectrum;(3)signal realization in original residuals of data set by the power-law *** to improved algorithm we constructed an ensemble pulsar timescale EPT-TAI using timing data with respect to International Atomic Time(TAI)about 16 yr time span of ten pulsars from International Pulsar Timing Array second data release(version A).The results show that EPT-TAI detected correctly the differences TT(BIPM2015)-TAI between terrestrial time TT(BIPM2015)and *** frequency stabilityσzanalysis shows that EPT-TAI does not indicate red noise for 16 yr time interval,and fractional frequency stability for 8 yr and longer time intervals is slightly better than that of TT(BIPM2015)-*** for short time intervals of TT(BIPM2015)-TAI is better than that of EPT-TAI,but TT(BIPM2015)-TAI shows red noise for longer time *** the same algorithm we also derived an ensemble pulsar timescale EPT-TT(BIPM2015)with respect to TT(BIPM2015).The fractional frequency stability curve of EPT-TT(BIPM2015)shows similar characteristics as that of EPT-TAI but with slightly lower values.

关键词： (stars:)pulsars general-time-methods data analysis

TIME-TEMPERATURE-STRESS EQUIVALENCE AND ITS APPLICATION TO NONLINEAR VISCOELASTIC MATERIALS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2001年第3期14卷 195-199页

作者： Luo Wenbo yang ting-Qing An Qunli Department of Mechanics Huazhong University of Science and TechnologyWuhan 430074China Institute of Fundamental Mechanics and Material Engineering Xiangtan UniversityXiangton 411105China

Stress-dependence of the intrinsic time of viscoelastic materialsis investigated. The influence of stress level on the intrinsic timeis considered to be similar to that of temperature, pressure, solventcon- centration, damage and physical aging. Thetime-temperature-stress equivalence principle is proposed, byemploying which, the creep curves at different temperatures andstress level can be shifted into a master curve at referencetemperature and stress level.

关键词： creep viscoelasticity time-temperature-stress equivalence principle