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Influence of toxic substances on dynamical behavior of a delayed diffusive predator-prey model

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International Journal of Biomathematics 2024年第2期17卷 177-200页

作者： Honglan zhu Xuebing Zhang hao Zhang Business School Huaiyin Institute of Technology Huai'an 223003P.R.China College of Mathematics and Statistics Nanjing University of Information Science and Technology Nanjing210044 P.R.China Jiangsu Key Laboratory of Trafic and Transportation Security Huaiyin Institute of Technology Huaian 223003P.R.China

In this paper,we propose and investigate a delayed diffusive predator-prey model affected by toxic *** first study the boundedness and persistence property of the *** analyzing the associated characteristic equation,we obtain the conditions for the existence of steady state bifurcation,Hopf bifurcation and Turing ***,we also study the Hopf bifurcation induced by the ***,our theoretical results are verified by numerical *** numerical observation results are in good agreement with the theoretically predicted *** and numerical simulations indicate that toxic substances have a great impact on the dynamics of the system.

关键词： Toxicant delay diffusion bifurcation spatial pattern

Molecular mechanism for the unusual enhancement of the second-step chemiluminescence production from the carcinogenic tetrabromohydroquinone and H2O_(2)

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Journal of Environmental Sciences 2024年第7期141卷 330-342页

作者： zi-Han Wang Chun-Hua Huang Zhi-Sheng Liu Li Mao Ben-Zhan zhu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Environment and Resources University of Chinese Academy of SciencesBeijing 100049China

We have found recently that two-step intrinsic hydroxyl radical(·OH)-dependent chemiluminescence(CL)could be produced by carcinogenic tetrahaloquinone and H_(2)O_(2).However,the first-step CL was too fast to clearly detect the stepwise generation of·OH and CL,and to distinguish the exact dividing point between the first-step and second-step *** we found that,extremely clear two-step intrinsic CL could be produced by the relative slow reaction of tetrabromohydroquinone(TBHQ)with H_(2)O_(2),which was directly dependent on the two-step·OH ***,the second-step,but not the first-step CL production of TBHQ/H_(2)O_(2)(CRET donor)was markedly enhanced by fluorescein(a typical xanthene dye,CRET acceptor)through a unique chemiluminescence resonance energy transfer(CRET)*** novel CRET system of TBHQ/H_(2)O_(2)/fluorescein was successfully applied for the sensitive detection of TBHQ with the detection limit as low as 2.5μmol/*** findings will help to develop more sensitive and highly efficient CL or CRET systems and specific CL sensor to detect the carcinogenic haloquinones,which may have broad environmental applications.

关键词： Two-step chemiluminescence Bromohydroquinone Hydrogen peroxide Hydroxyl radical CRET

A real-time calibration method based on time-to-digital converter for accelerator timing system

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Nuclear Science and Techniques 2024年第9期35卷 127-140页

作者： Qi-hao Duan Liang Ge Yan-hao Jia Jie-Yu zhu Wei Zhang Institute of modern physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

The high-intensity heavy-ion accelerator facility(HIAF)is a scientific research facility complex composed of multiple cas-cade accelerators of different types,which pose a scheduling problem for devices distributed over a certain range of 2 km,involving over a hundred *** white rabbit,a technology-enhancing Gigabit Ethernet,has shown the capability of scheduling distributed timing devices but still faces the challenge of obtaining real-time synchronization calibration param-eters with high *** study presents a calibration system based on a time-to-digital converter implemented on an ARM-based System-on-Chip(SoC).The system consists of four multi-sample delay lines,a bubble-proof encoder,an edge controller for managing data from different channels,and a highly effective calibration module that benefits from the SoC *** performance was evaluated with an average RMS precision of 5.51 ps by measuring the time intervals from 0 to 24,000 ps with 120,000 data for every *** design presented in this study refines the calibration precision of the HIAF timing *** eliminates the errors caused by manual calibration without efficiency loss and provides data support for fault *** can also be easily tailored or ported to other devices for specific applications and provides more space for developing timing systems for particle accelerators,such as white rabbits on HIAF.

关键词： HIAF White rabbit Calibration system Time-to-digital converter(TDC)

Dynamics Modeling and Parameter Identification for a Coupled-Drive Dual-Arm Nursing Robot

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 243-257页

作者： hao Lu Zhiqiang Yang Deliang zhu Fei Deng Shijie Guo College of Electronic Information and Automation Tianjin University of Science and TechnologyTianjin 300222China Academy for Engineering&Technology Fudan UniversityShanghai 200433China Shanghai Engineering Research Center of AI&Robotics Shanghai 200433China School of Mechanical Engineering Hebei University of TechnologyTianjin 300130China

A dual-arm nursing robot can gently lift patients and transfer them between a bed and a *** its lightweight design,high load-bearing capacity,and smooth surface,the coupled-drive joint is particularly well suited for these ***,the coupled nature of the joint disrupts the direct linear relationship between the input and output torques,posing challenges for dynamic modeling and practical *** study investigated the transmission mechanism of this joint and employed the Lagrangian method to construct a dynamic model of its internal *** on this foundation,the Newton-Euler method was used to develop a dynamic model for the entire robotic arm.A continuously differentiable friction model was incorporated to reduce the vibrations caused by speed transitions to *** experimental method was designed to compensate for gravity,inertia,and modeling errors to identify the parameters of the friction *** method establishes a mapping relationship between the friction force and motor *** addition,a Fourier series-based excitation trajectory was developed to facilitate the identification of the dynamic model parameters of the robotic *** tracking experiments were conducted during the experimental validation phase,demonstrating the high accuracy of the dynamic model and the parameter identification method for the robotic *** study presents a dynamic modeling and parameter identification method for coupled-drive joint robotic arms,thereby establishing a foundation for motion control in humanoid nursing robots.

关键词： Nursing-care robot Coupled-drive joint Dynamic modeling Parameter identification

The Astrometric Performance of the China Space Station Telescope(CSST)Sky Survey in Extending the Gaia Celestial Reference Frame

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Research in Astronomy and Astrophysics 2024年第8期24卷 133-140页

作者： Jun Yao Jia-Cheng Liu Niu Liu zi zhu Zhen-Wei Wang School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics(Ministry of Education)Nanjing UniversityNanjing 210023China University of Chinese Academy of Sciences Nanjing 211135China

The multi-color imaging sky survey conducted by the China Space Station Telescope(CSST)holds significant promise for advancing the development of the celestial reference *** this study,we focus on assessing the astrometric performance of the CSST celestial reference frame(CSST-CRF)in extending the Gaia Celestial Reference Frame 3(Gaia-CRF3).First,the orientation precision of the CSST reference frame is evaluated using a simulated set of extragalactic sources with CSST g magnitudes ranging from 18 to 25 *** estimated orientation uncertainty caused by random error insignificantly affects the alignment between Gaia-CRF3 and the ***,the systematic effect of incomplete CSST sky coverage on the alignment between CSST-CRF and Gaia-CRF3 is discussed by analyzing the differences between the subset of Gaia-CRF3 in the CSST observation region(Gaia-CRF3′)and Gaia-CRF3 as a *** the third International Celestial Reference Frame(ICRF3)S/X band as an intermediate reference frame,the orientation offset between Gaia-CRF3′and GaiaCRF3 is estimated to be 20μ*** offset is marginally larger than the orientation offset between Gaia-CRF3 and the ICRF3,approximately 15μ*** residual spin and glide rate of Gaia-CRF3′are derived from the proper motions,consistent with that of Gaia-CRF3 within the formal ***,we explore the role of CSST in establishing a multi-band celestial reference frame by comparing its limiting magnitude and observation accuracy with existing catalogs in the infrared and ultraviolet *** to its broad wavelength coverage and highprecision measurements,CSST is well-positioned to make significant contributions to the development of a multiband celestial reference frame.

关键词： astrometry-reference systems-surveys

Integrating machine learning and CALPHAD method for exploring low-modulus near-β-Ti alloys

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Rare Metals 2024年第1期43卷 309-323页

作者： hao Zou Yue-Yan Tian Li-Gang Zhang Ren-hao Xue zi-Xuan Deng Ming-Ming Lu Jian-Xin Wang Li-Bin Liu School of Computer Science and Engineering Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This study developed a method that combines machine learning with calculation of phase diagrams(CALPHAD) to facilitate the design of near-β-Ti alloys. An elastic modulus database of Ti–Nb–Zr–Mo–Ta–Sn system was constructed first, and then three features(the electron to atom ratio, mean absolute deviation of atom mass, and mean electronegativity) were selected as the key factors of modulus by performing a three-step feature selection. With these features, a highly accurate model was built for predicting the modulus of near-β-Ti alloys. To further ensure the accuracy of modulus prediction, machine learning with the elastic constants calculated was leveraged by CALPHAD database. The root mean square error of the well-trained model can be as low as 6.75 GPa. Guided by the prediction of machine learning and CALPHAD, three novel near-β-Ti alloys with elastic modulus below 50 GPa were successfully designed in this study. The best candidate alloy(Ti–26Nb–4Zr–4Sn–1Mo–Ta) exhibits an ultra-low modulus(36.6 GPa) after cold rolling with a thickness reduction of 20%. Our method can greatly save time and resources in the development of novel Ti alloys, and experimental verifications have demonstrated the reliability of this method.

关键词： Near-β-Ti alloy Machine learning Calculation of phase diagram Low-modulus alloy Feature selection

Remote copper-catalyzed enantioselective substitution of yne-thiophene carbonates

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Science China Chemistry 2024年第4期67卷 1175-1180页

作者： hao-Dong Qian Xiang Li Tingrui Yin Wei-Feng Qian Chunhui Zhao Cuiju zhu hao Xu CCNU-uOttawa Joint Research Centre Key Laboratory of Pesticides&Chemical Biology of Ministry of EducationInternational Joint Research Center for Intelligent Biosensing Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

Here,we describe a strategy for the copper-catalyzed asymmetric heteroarylation of yne-thiophene carbonates with indoles via remote *** key to the success of this strategy lies in the design of the alkynyl group at the ortho-position of the heterocycle thiophene,enabling the formation of a triarylmethane moiety via very remote ***,the concept of remote copper-catalyzed asymmetric transformation extends not only to yne-allylic esters but also to yne-aryl *** reaction readily provides a diverse array of chiral triarylmethanes with high efficiency,enantioselectivity,and excellent functional group ***,facile follow-up transformations underscore their potential utility in the synthesis of various enantioenriched building *** mechanistic studies support the plausibility of the remote substitution pathway.

关键词： remote substitution copper catalyst asymmetric catalysis triaryl methanes

ziF-8 modified by isocyanate as a photocatalytic antibacterial agent

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Rare Metals 2024年第6期43卷 2708-2718页

作者： Yi-Ning Zhang Zhen Pei zi-hao Wang Chong-En Wang Fen-Fen Liang Li-Qiao Wei College of Architecture Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Interface Science and Engineering in Advanced Materials of Taiyuan University of Technology Ministry of EducationTaiyuan 030024China Department of Materials Science and Engineering Shanxi Institute of TechnologyYangquan 045000China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030000China

Zeolite imidazole skeleton(ziF-8)is a promising option for self-cleaning of building exterior walls due to its large specific surface area,high antibacterial activity and low ***,it suffers from low antibacterial efficiency and yield under visible light *** address the issues,we developed the photocatalytic materials T-ziF-8-TDI(thermally treated-ziF-8-toluene 2,4-diisocyanate)by modifying ziF-8 with thermal oxygen sensitization and chemical *** results show that the yield of T-ziF-8-TDI photocatalytic antibacterial agent is increased to 11.5 times of that of T-ziF-8,while maintaining the crystal structure of T-ziF-8 and thermal stability up to 60℃.Furthermore,T-ziF-8-TDI exhibits extended optical response range to the nearinfrared region,significantly narrowed band gap,improved photogenerated elec tron-hole separation efficiency,reduced recombination rate,and excellent photocatalytic *** the concentration of antibacterial agent is 600 mg·L^(-1),the antibacterial rate of Escherichia coli(***)reaches 99.99%irradiated by visible light for30 min,and when the concentration of antibacterial agent is 200 mg·L^(-1),the antibacterial rate of Staphylococcus aureus(***)reaches 99.99%irradiated by visible light for 25 *** also analyzed the reasons in detail from the aspects of bacterial species and antibacterial mechanism,and proposed the antibacterial mechanism of·O_(2)^(-)and h^(+)as the main active *** findings suggest that T-ziF-8-TDI photocatalytic antibacterial agent has potential for use in self-cleaning of building exterior walls.

关键词： ziF-8 Hot oxygen sensitization Modified by isocyanate Antimicrobial performance Photocatalytic antibacterial mechanism

Effects of nutrient limitations on the sinking velocity of Thalassiosira weissflogii

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Acta Oceanologica Sinica 2024年第6期43卷 163-172页

作者： Jie zhu Qiang hao Wei Zhang Yingying Ma Jiangning Zeng Ocean College Zhejiang UniversityZhoushan 316000China Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China Key Laboratory of Marine Ecosystem Dynamics Ministry of Natural ResourcesHangzhou 310012China Zhejiang Key Laboratory of Nearshore Engineering Environment and Ecological Security Hangzhou 310012China Tianjin Key Lab of Aqua-Ecology and Aquaculture College of FisheriesTianjin Agricultural UniversityTianjin 300384China

The sinking of diatoms is critic al to the formation of oceanic biological pumps and coastal hypoxic ***,little is known about the effects of different nutrient restrictions on diatom *** this study,we measured the sinking velocity(SV) of Thalassiosira weissflogii using a new phytoplankton video observation instrument and analyzed major biochemical components under varying nutrient *** results showed that the SV of *** under different nutrient limitation conditions varied *** highest SV of(1.77±0.02) m/d was obtained under nitrate limitation,signific antly surpassing that under phosphate limitation at(0.98±0.13) m/*** the nutrient limitation was released,the SV steadily decreased to(0.32±0.03) m/d and(0.15±0.05) m/d,***;under conditions with limited nitrate and phosphate concentrations,the SV values of *** significantly positively correlated with the lipid content(P <0.001),with R^(2) values of 0.86 and 0.69,*** change of the phytoplankton SV was primarily related to the intracellular compo sition,which is controlled by nutrient conditions but did not significantly correlate with transparent extracellular polymer and biosilica *** results of this study help to understand the regulation of the vertical sinking process of diatoms by nutrient restriction and provide new insights into phytoplankton dynamics and their relationship with the marine nutrient structure.

关键词： nutrient limitation Thalassiosira weissflogii sinking velocity biochemical component lipid content