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The General Solution and Ulam Stability of Second Order linear Dynamic Equations on Time Scales

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Journal of Mathematical Research with Applications 2020年第5期40卷 493-506页

作者： Yonghong SHEN Yongjin Li School of Mathematics and Statistics Tianshui Normal University Department of Mathematics Sun Yat-Sen University

By using the variation of parameters, this paper deals with the general solution and Ulam stability of second order linear dynamic equations with variable coefficients on time scales.In particular, we also obtain the ... 详细信息

关键词： Ulam stability second order linear dynamic equations time scales

Effect of poly(4-tert-butylstyrene)block length on the microphase structure of poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4-tert-butylstyrene)triblock terpolymers

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Chinese Chemical Letters 2023年第6期34卷 551-555页

作者： Kun An Jia Gao Yihang Chen Jingjing Nie Yongjin Li Junting Xu Binyang Du State Key Laboratory of Motor Vehicle Biofuel Technology Department of Polymer Science&EngineeringZhejiang UniversityHangzhou 310027China College of Material Chemistry and Chemical EngineeringHangzhou Normal UniversityHangzhou 310036China Department of Chemistry Zhejiang UniversityHangzhou 310027China

A series of linear poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4-tert-butylstyrene)(PEO_(113)-b-PVBC_(130)-b-Pt BS_(x)or E_(113)V_(130)T_(x))triblock terpolymers with various lengths x(=20,33,66,104,215)of Pt BS block were synthesized via a two-step reversible addition-fragmentation chain transfer(RAFT)polymerization.The E_(113)V_(130)T_(x)triblock terpolymers were non-crystalline because the PVBC and Pt BS blocks strongly hindered the crystallization of PEO block.The effects of Pt BS block length x on the phase structures of E_(113)V_(130)T_(x)triblock terpolymers were investigated by combined techniques of small-angle X-ray scattering(SAXS)and transmission electron microscopy(TEM).It was found that with increasing x from20 to 215,the phase structure of E_(113)V_(130)T_(x)triblock terpolymers became more ordered and changed from disordered structure,hexagonally-packed cylinder(HEX),hexagonally perforated layer(HPL),to lamellar(LAM)phase structures.Temperature-variable SAXS measurements showed that the HEX,HPL and LAM phase structures obtained for E_(113)V_(130)T_(66),E_(113)V_(130)T_(104)and E_(113)V_(130)T_(215)by thermal annealing,respectively,were thermodynamically stable in the temperature range of 30-170℃.

关键词： ABC triblock terpolymer Phase structure SAXS HPL Thermodynamically stable

Boundedness for a Class of Operators on Weighted Morrey Space with RD-measure

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Journal of Partial Differential Equations 2022年第4期35卷 395-408页

作者： CUI Xiaona LU yongjin li Mengmeng Department of Mathematics and Information Science Henan Normal UniversityXinxiang 453007China Department of Mathematics and Statistics Oakland UniversityRochesterMI48309USA College of International Education Henan Normal UniversityXinxiang 453007China.

this paper,we study a class of sublinear operators and their commutators with a weighted BMO function.We first give the definition of a weighted Morrey space Lpo(X)where X is an RD-measure and w is the weight function.The weighted Morrey spaces arise from studying the local behavior of solutions to certain partial differential equations.We will show that the aforementioned class of operators and their communtators with a weighted BMO function are bounded in the weighted Morrey space LPpto(X)provided that the weight function w belongs to the Ap(μ)-class and satisfiesthereverseHolder'scondition.

关键词： Weighted Morrey space RD-measure commutator

Enhancement of solar-driven photocatalytic activity of oxygen vacancy-rich Bi/BiOBr/Sr_(2)LaF_(7)∶Yb^(3+),Er^(3+)composites through synergetic strategy of upconversion function and plasmonic effect

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Journal of Environmental Sciences 2022年第5期34卷 76-87页

作者： Yongjin Li Yingying Zhang Jiajing Wang Youzhun Fan Taizhong Xiao Zhaoyi Yin Tianhui Wang Jianbei Qiu Zhiguo Song School of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

For better use of solar energy,the development of efficient broadband photocatalyst has attracted extraordinary attention.In this study,a ternary composite consisting of Sr_(2)LaF_(7)∶Yb^(3+),Er^(3+)upconversion(UC)nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies(OVs,SLFBB)was designed and synthesized by multi-step solvent-thermal method.Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr_(2)LaF_(7)∶Yb^(3+),Er^(3+)composites(SFLB)are clarified.The Bi metal and OVs enhanced the light-harvesting capacity in the region of visible-near-infrared(Vis-NIR),and promoted the separation of electron-hole(e-/h+)pairs.Furthermore,the surface plasmon resonance(SPR)effect of Bi metal can improve the energy transfer from Sr_(2)LaF_(7)∶Yb^(3+),Er^(3+)to BiOBr via nonradiative energy transfer process,resulting in enhancing the light utilization from up-converting NIR into Vis light.Due to the synergistic effects of UC function,SPR and OVs,the SFLBB exhibited obviously enhanced photocatalytic ability for the degradation of BPA with a rate of 8.9×10^(-3) min^(-1),which is about 2.78 times higher than 3.2×10^(-3) min^(-1) of BiOBr(BOB)under UV-Vis-NIR light irradiation.This work provides a novel strategy for the project of high-efficiency Bismuth-based broadband photocatalysts,which is helpful to fur-ther understand the mechanism of enhanced photocatalysis by UC function and plasmonic effect.

关键词： BiOBr/Sr_(2)LaF_(7)∶Yb^(3+),Er^(3+)composites In-situ generation Bi metal Oxygen vacancies Broadband photocatalysis

Determination of interfacial tension and viscosity under dripping flow in a step T-junction microdevice

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Chinese Journal of Chemical Engineering 2022年第2期35卷 210-218页

作者： li Ma yongjin Cui lin Sheng Chencan Du Jian Deng Guangsheng Luo State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Microfluidic approaches for the determination of interfacial tension and viscosity of liquid-liquid systems still face some challenges.One of them is liquid-liquid systems with low interfacial and high viscosity,because dripping flow in normal microdevices can’t be easily realized for the systems.In this work,we designed a capillary embedded step T-junction microdevice to develop a modified microfluidic approach to determine the interfacial tension of several systems,specially,for the systems with low interfacial tension and high viscosity.This method combines a classical T-junction geometry with a step to strengthen the shear force further to form monodispersed water/oil(w/o)or aqueous two-phase(ATP)droplet under dripping flow.For systems with low interfacial tension and high viscosity,the operating range for dripping flow is relative narrow whereas a wider dripping flow operating range can be realized in this step Tjunction microdevice when the capillary number of the continuous phase is in the range of 0.01 to 0.7.Additionally,the viscosity of the continuous phase was also measured in the same microdevice.Several different systems with an interfacial tension from 1.0 to 8.0 m N·m^(-1) and a viscosity from 0.9 to 10 m Pa·s were measured accurately.The experimental results are in good agreement with the data obtained from a commercial interfacial tensiometer and a spinning digital viscometer.This work could extend the application of microfluidic flows.

关键词： Step T-junction Interfacial tension Viscosity Force balance

Mitochondrial diseases and mtDNA editing

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Genes & Diseases 2024年第3期11卷 303-310页

作者： Min Song lingqun Ye yongjin Yan Xuechun li Xinglong Han Shijun Hu Miao Yu Department of Cardiovascular Surgery of the First Affiliated Hospital&Institute for Cardiovascular Science Collaborative Innovation Center of HematologyState Key Laboratory of Radiation Medicine and ProtectionSuzhou Medical CollegeSoochow UniversitySuzhouJiangsu 215000China Hai'an People's Hospital NantongJiangsu 226600China

Mitochondrial diseases are a heterogeneous group of inherited disorders character-ized by mitochondrial dysfunction,and these diseases are often severe or even fatal.Mito-chondrial diseases are often caused by mitochondrial DNA mutations.Currently,there is no curative treatment for patients with pathogenic mitochondrial DNA mutations.With the rapid development of traditional gene editing technologies,such as zinc finger nucleases and tran-scription activator-like effector nucleases methods,there has been a search for a mitochon-drial gene editing technology that can edit mutated mitochondrial DNA;however,there are still some problems hindering the application of these methods.The discovery of the DddA-derived cytosine base editor has provided hope for mitochondrial gene editing.In this paper,we will review the progress in the research on several mitochondrial gene editing technologies with the hope that this review will be useful for further research on mitochondrial gene editing technologies to optimize the treatment of mitochondrial diseases in the future.

关键词： Gene editing Mitochondrialdisease MitochondrialDNA mutation Transcription activator-like effectornucleases Zinc finger nucleases

Adversarial Active Learning for Named Entity Recognition in Cybersecurity

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Computers, Materials & Continua 2021年第1期66卷 407-420页

作者： Tao li yongjin Hu Ankang Ju Zhuoran Hu Zhengzhou Institute of Information Science and Technology Zhengzhou450001China College of Letters and Science University of Wisconsin-MadisonMadison53706USA

Owing to the continuous barrage of cyber threats,there is a massive amount of cyber threat intelligence.However,a great deal of cyber threat intelligence come from textual sources.For analysis of cyber threat intelligence,many security analysts rely on cumbersome and time-consuming manual efforts.Cybersecurity knowledge graph plays a significant role in automatics analysis of cyber threat intelligence.As the foundation for constructing cybersecurity knowledge graph,named entity recognition(NER)is required for identifying critical threat-related elements from textual cyber threat intelligence.Recently,deep neural network-based models have attained very good results in NER.However,the performance of these models relies heavily on the amount of labeled data.Since labeled data in cybersecurity is scarce,in this paper,we propose an adversarial active learning framework to effectively select the informative samples for further annotation.In addition,leveraging the long short-term memory(LSTM)network and the bidirectional LSTM(BiLSTM)network,we propose a novel NER model by introducing a dynamic attention mechanism into the BiLSTM-LSTM encoderdecoder.With the selected informative samples annotated,the proposed NER model is retrained.As a result,the performance of the NER model is incrementally enhanced with low labeling cost.Experimental results show the effectiveness of the proposed method.

关键词： Adversarial learning active learning named entity recognition dynamic attention mechanism

Color tunable and white light emitting via energy transfer in single-phase BiOCl:Er^(3+),Sm^(3+) phosphors for WLEDs

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Journal of Rare Earths 2018年第3期36卷 231-237页

作者： Xiangzhou Zhang Yongjin Li Rui Hu Zuyuan Xu Jianbei Qiu Zhengwen Yang Zhiguo Song School of Materials Science and Engineering Kunming University of Science and Technology School of Materials Science and Engineering Sun Yat-sen University

BiOCl crystal shows potential as efficient optical host due to its special layered structure. Here,the luminescence properties of the Er^3＋/Sm^3＋ co-doped BiOCl phosphors as single-phase phosphors were reported. Upon near ultraviolet excitation（NUV, 380 nm corresponding the ^4 I15/2→ ^4 G11/2 transition of Er^3＋ ions）, the phosphors exhibit the efficient characteristic emissions of Er^3＋ and Sm^3＋ ions simultaneously. The energy transfer（ET） from Er^3＋ to Sm^3＋ ions in the layered crystals has been validated by the variation of emission intensities and decay lifetimes respectively, which is ascribed to be a dipoledipole interaction. By virtue of the ET behavior and increasing Sm^3＋ ion concentration, the enhancing emission intensity of Sm^3＋ and the tunability of emission color from yellowish-green（0.318, 0.420） to white（0.343, 0.347） are realized. The results of our work indicate that the Er^3＋/Sm^3＋ co-doped BiOCI phosphor has a promising application serving as single component white emitting phosphors for NUV excited WLEDs.

关键词： BiOCl Er^3＋ Sm^3＋ Color tunable Photoluminescence Energy transfer

The Complex Dynamics of Hepatitis B Infected Individuals with Optimal Control

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Journal of Systems Science & Complexity 2021年第4期34卷 1301-1323页

作者： DIN Anwarud li yongjin SHAH Murad Ali Department of Mathematics Sun Yat-sen UniversityGuangzhou 510275China School of Mathematical Sciences Beiing Normal UniversityBeijing 100875China

This paper proposes various stages of the hepatitis B virus(HBV)besides its transmissibility and nonlinear incidence rate to develop an epidemic model.The authors plan the model,and then prove some basic results for the well-posedness in term of boundedness and positivity.Moreover,the authors find the threshold parameter R0,called the basic/effective reproductive number and carry out local sensitive analysis.Furthermore,the authors examine stability and hence condition for stability in terms of R0.By using sensitivity analysis,the authors formulate a control problem in order to eradicate HBV from the population and proved that the control problem actually exists.The complete characterization of the optimum system was achieved by using the 4th-order Runge-Kutta procedure.

关键词： Hepatitis B epidemic model non-linear incidence normalized sensitivity index numerical simulation optimization theory reproduction number stability analysis