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Design and synthesis of thiol-terminated imidothioether oligomer as thermally latent hardener and modifier for high-performance epoxy/thiol thermosets

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Science China Chemistry 2024年第2期67卷 632-641页

作者： Xing Liu jianjun zhou Shumei Liu Jianqing Zhao School of Materials Science and Engineering South China University of TechnologyGuangzhou510640China Key Lab Guangdong High Property&Functional Polymer Materials Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangzhou510640China

Conventional base-catalyzed epoxy/aliphatic thiol systems have a poor storage stability,and are impossible to be one-pot systems.A widely accepted solution is to use the latent catalysts,which are usually insoluble anionic initiators sensitive to impurities and moisture,and have many limitations in practical use.In this work,a soluble thiol-terminated imidothioether oligomer(TPI) was synthesized and used as a latent hardener and modifier to prepare one-pot epoxy/thiol systems without the latent catalysts.The latent behavior and curing mechanism of epoxy systems(EP/TPI series),consisted of bisphenol A diglycidyl ether(DGEBA),pentaerythritol tetrakis(mercaptoacetate)(PETMP) and TPI,were proposed.The thiol exchange reaction between TPI and PETMP preceded the curing reaction of DGEBA,and produced aromatic thiols,which were unreactive at ambient conditions and reacted with DGEBA to form the thermosets at temperatures above 130 ℃.At the loading of 24.4 wt%TPI,the epoxy system(EP/TPI-3) had a shelf life of 13 days and was completely cured within 20 min at 180 ℃.Meanwhile,the catalyst-free curing process of EP/TPI-3 system was insensitive to impurities and moisture.Furthermore,the thermal and mechanical properties of EP/TPI-3 thermoset were simultaneously improved,thereinto,the glass transition temperature,Young's modulus and ultimate tensile strength were increased by 16.7 ℃,12.9%,and 13.6%,respectively,compared with those of the commercial DGEBA/PETMP thermoset.This work shows that TPI has the potential to be a powerful alternative to commercial latent catalysts,and EP/TPI thermosets with high performance have broad application prospects.

关键词： thiol-terminated imidothioether oligomer epoxy systems thiol exchange reaction thermal latency high performance

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Dynamics of a predator-prey system with sublethal effects of pesticides on pests and natural enemies

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International Journal of Biomathematics 2024年第1期17卷 151-175页

作者： Xiangjun Dai jianjun Jiao Qi Quan Airen zhou School of Mathematical Sciences Guizhou Normal University Guiyang 550025P.R.China School of Mathematics and Statistics Guizhou University of Finance and Economics Guiyang 550025 P.R.China School of Date Science Tongren University Tongren 554300P.R.China

Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic spraying pesticide and releasing predatory natural enemies.By using the Floquet theory and the comparison theorem of impulsive differential equations,a sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is obtained.The persistence of the system is further studied,and a sufficient condition for the persistence of the system is obtained.Finally,some numerical simulations are shown to verify our theoretical works.Our works indicate that the sublethal effects of insecticides and the release of predatory natural enemies play significant roles in pest control in agricultural production.

关键词： Predator-prey system sublethal effect global asymptotic stability permanence

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Antibody-modified integrated microfluidic terahertz biosensor for detection of breast cancer biomarkers

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Optoelectronics Letters 2024年第4期20卷 249-256页

作者： LIU jianjun School of Intelligent Engineering Shaoguan UniversityShaoguan 512005China

Breast cancer is the most common malignant tumor in women,which seriously threatens the physical and mental health of women worldwide.The existing detection methods have problems,such as large sample consumption,time-consuming sample preparation,expensive equipment,and low sensitivity.In order to solve these problems,this paper proposes a method for quickly detecting breast cancer using surface-functionalized terahertz metamaterial biosensors.The use of PIK3CA-modified sensors enhances the detection sensitivity and specificity of exosomes.Based on the red shift of the sensor absorption peak caused by exosomes,breast cancer patients can be distinguished from healthy controls.This study demonstrates that exosome detection is effective for the repeatable and non-invasive diagnosis of breast cancer patients.The terahertz metamaterial biosensor designed in this paper has high specificity,repeatability,and sensitivity,and has great potential for application in the development of modern diagnostic instruments.

关键词： specificity diagnosis modified

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Experimental study on shock interaction control of double wedge in high-enthalpy hypersonic flow subject to plasma synthetic jet

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Chinese Journal of Aeronautics 2024年第4期37卷 151-165页

作者： Xuzhen XIE Qiang LIU Yan zhou Zhenbing LUO Wei XIE Guanghui BAI Kai LUO Qiu WANG jianjun WU College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China China Academy of Launch Vehicle Technology Beijing 100076China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The hypersonic shock-shock interaction flow field at double-wedge geometries controlled by plasma synthetic jet actuator is experimentally studied in a Ma = 8 high-enthalpy shock tunnel with the purpose of exploring a novel technique for reducing surface heat flux in a real flight environment. The results demonstrate that increasing the discharge energy is advantageous in eliminating the shock wave, shifting the shock wave interaction point, and shortening the control response time. The oblique shock wave can be completely removed when the actuator's discharge energy grows from 0.4 J to 11.5 J, and the displacement of the shock wave interaction point increases by 124.56%, while the controlled response time is shortened by 30 μs. Besides, the reduction in diameter of the jet exit is firstly proved to have a negative impact on energy deposition in a working environment with incoming flow, which reduces the discharge energy and hence decreases the control effect. The shock wave control response time lengthens when the jet exits away from the second wedge. Along with comparing the change in wall heat flux at the second wedge over time, the control effect of plasma synthetic jet actuator with and without inflation is also analyzed. When plasma synthetic jet works in inflatable mode, both the ability to eliminate shock waves and the shifting effect of the shock wave interaction point are increased significantly, and the wall heat flux is also reduced.

关键词： Hypersonic flow High-enthalpy flow Plasma synthetic jet Shock wave Flow control

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Single transmembrane GPCR modulating proteins:neither single nor simple

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Protein & Cell 2024年第6期15卷 395-402页

作者： Meng Wang jianjun Lyu Chao Zhang Department of Plastic and Reconstructive Surgery Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011China Hubei Topgene Research Institute of Hubei Topgene Biotechnology Co. LtdEast Lake High-Tech Development ZoneWuhan 430205China Fundamental Research Center Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center)Tongji UniversityShanghai 200092China

The discovery of G-protein coupled receptor(GPCR)accessory proteins has fundamentally redefined the pharmacological concept of GPCR signaling,demonstrating a more complex molecular basis for receptor specificity on the plasma membrane and impressionable downstream intracellular cascades.GPCR accessory proteins not only contribute to the proper folding and trafficking of receptors but also exhibit selectable receptor preferences.

关键词： specificity GPCR neither

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Coseismic Coulomb stress changes induced by a 2020-2021 M_(W)>7.0 Alaska earthquake sequence in and around the Shumagin gap and its influence on the Alaska-Aleutian subduction interface

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Geodesy and Geodynamics 2024年第1期15卷 1-12页

作者： Lei Yang jianjun Wang Caijun Xu School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China Collaborative Innovation Center of Geospatial Technology Wuhan 430079China Key Laboratory of Geospace Environment and Geodesy Ministry of EducationWuhan UniversityWuhan 430079China

Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.

关键词： The 2020-2021 Alaska earthquake sequence Coseismic Coulomb stress change Mainshock-aftershock triggering The Alaska-Aleutian subduction interface The Shumagin gap

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Optimal impulsive rendezvous for highly elliptical orbits using linear primer vector theory

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Chinese Journal of Aeronautics 2024年第3期37卷 194-207页

作者： Maozhang ZHENG jianjun LUO Zhaohui DANG National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi’an 710072China

In this paper,minimum-fuel rendezvous is investigated for the case in which the reference orbit is highly elliptic.To this end,the well-known Tschauner-Hempel equations are used to describe the relative motions between rendezvous spacecraft and the target.Lawden’s primer vector theory is then applied on this linear but time-varying system.The analytical solution of the required primer vector for this problem is then derived by using a recently developed method.For the existing non-optimal solutions which don’t satisfy the conditions,the methods are further designed to improve the performance by shifting impulses or adding a new one.Finally,two algorithms are developed for free-impulse time-fixed rendezvous problems.The first algorithm can determine the globally optimal trajectory with the optimal number of impulses.The second one enables for fast trajectory planning.The proposed algorithms have been successfully applied to coplanar and three-dimensional rendezvous problems in which the target is flying on highly elliptical orbits.

关键词： Orbital transfer Optimal trajectory Primer vector Tschauner-Hempel equations Globally planning Fast planning

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Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

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Building Simulation 2024年第4期17卷 561-574页

作者： Yichi Zhang jianjun Xia Midea HVAC Heating&Ventilation Equipment Co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)systems.Despite being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land use.To close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit sites.Based on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected considering several criteria from land uses and construction difficulties.The costs of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable sites.The assessment is conducted for the northern China where DH systems and significant seasonal differences of energy demand exist.In total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern China.The results also prove that 682 valley sites can be achieved with a dam cost lower than 20 CNY/m^(3).By conducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and constructions are also found.Furthermore,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH systems.In general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH demand.The novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

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Grassland-type ecosystem stability in China differs under the influence of drought and wet events

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Journal of Arid Land 2024年第5期16卷 615-631页

作者： CAO Wenyu BAI jianjun YU Leshan School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China International Business School Shaanxi Normal UniversityXi'an 710119China

Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.

关键词： grassland ecosystem stability resistance resilience different climate types drought climate event wet climate event

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A Planning Method for Operational Test of UAV Swarm Based on Mission Reliability

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1889-1918页

作者： Jingyu Wang Ping Jiang jianjun Qi College of Systems Engineering National University of Defense TechnologyChangsha410073China Beijing Special Engineering Design Institution Beijing100028China

The unmanned aerial vehicle(UAV)swarm plays an increasingly important role in the modern battlefield,and the UAV swarm operational test is a vital means to validate the combat effectiveness of the UAV swarm.Due to the high cost and long duration of operational tests,it is essential to plan the test in advance.To solve the problem of planning UAV swarm operational test,this study considers the multi-stage feature of a UAV swarm mission,composed of launch,flight and combat stages,and proposes a method to find test plans that can maximize mission reliability.Therefore,a multi-stage mission reliability model for a UAV swarm is proposed to ensure successful implementation of the mission.A multi-objective integer optimization method that considers both mission reliability and cost is then formulated to obtain the optimal test plans.This study first constructs a mission reliability model for the UAV swarm in the combat stage.Then,the launch stage and flight stage are integrated to develop a complete PMS(Phased Mission Systems)reliability model.Finally,the Binary Decision Diagrams(BDD)and Multi Objective Quantum Particle Swarm Optimization(MOQPSO)methods are proposed to solve the model.The optimal plans considering both reliability and cost are obtained.The proposed model supports the planning of UAV swarm operational tests and represents a meaningful exploration of UAV swarm test planning.

关键词： UAV swarm PMS MOQPSO BDD mission reliability operational test planning

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