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Time-dependent color-tunable room temperature phosphorescence from unusual conformational transitions in phenothiazine polymers under UV irradiation

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science China Chemistry 2025年第3期68卷 1091-1098页

作者： Jiwen Lu Yifan Niu Chanjuan Jin Chengheng Wu Hanyu Wang Yan Guan Ping Wang Xinghe Fan Key Lab of Environment-Friendly Chemistry and Application of Ministry of Education Key Laboratory of Polymeric Materials and Application Technology of Hunan ProvinceKey Laboratory of Advanced Functional Polymer Materials of CollegesUniversities of Hunan ProvinceCollege of ChemistryXiangtan UniversityXiangtan 411105China Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Achieving color-tunable room-temperature phosphorescence(RTP),especially including blue RTP from a single-component polymer still faces a formidable ***,we wisely choose conformation-dependent phenothiazine with trifluoromethyl substituent as the side group of the phosphor monomer(Cz PT)and then copolymerize it with N-isopropylacrylamide(NIPAM)through photopolymerization to obtain polymers PPCz ***-dependent color-tunable phosphorescence from unusual quasi-equatorial(eq)to quasi-axial(ax)conformers are obtained,and the RTP color changes from orange(550 nm)to blue(470 nm)with phosphorescence lifetime up to 0.96 *** theoretical calculations confirm that the quasi-axial conformer is the preferred structure that facilitates the formation of intramolecular hydrogen bonds on the trifluoromethyl *** EPR spectra illustrate that the persistent UV irradiation generates radical cations to induce the conformational transitions first,followed by photopolymerization immobilizing the ax conformation in PPCz *** of data encryption and anti-counterfeiting are fabricated to show prompt and delayed multicolor *** work affords a simple and feasible avenue for two-dimensional color tunable room temperature phosphorescence from a single-component polymer.

关键词： polymeric room temperature phosphorescence color-tunable phosphorescence conformation-dependent time-dependent blue phosphorescence

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The misalignment between degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy during the degradation evaluation in modified Hanks’solutions

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Journal of Magnesium and Alloys 2024年第9期12卷 3661-3674页

作者： Di Mei Qingyuan Zhang Yaqian Li Mengyao Liu Wenkai Li Pingli Jiang Ruiqing Hou Shijie Zhu Liguo Wang Shaokang Guan School of Materials Science and Engineering&Henan Key Laboratory of Advanced Magnesium Alloy Zhengzhou UniversityZhengzhou 450001China Center of Advanced Analysis&Gene Sequencing Zhengzhou UniversityZhengzhou 450001China Key Laboratory of Advanced Materials Processing&Mold Ministry of Education Zhengzhou 450002China

The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic *** the most of the related publications mainly focused on the degradation rate of Mg-based materials,but rare to care about the changes of their mechanical properties during the immersion period,which can significantly affect their service *** link between residual strength and Mg degradation is not appreciated *** this work,a series media were constructed based on Hanks’solution,the effects of inorganic ions on the degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy were *** results indicated that the degradation behavior of Mg alloy was mainly controlled by degradation products and there is no direct correspondence between the degradation rate change and mechanical integrity of Mg *** relevant findings are beneficial for selecting the monitoring index in Mg corrosion tests and evaluating the service reliability of Mg alloys for biomedical applications.

关键词： Magnesium alloy Degradation rate Mechanical integrity Hanks’solution

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Wire arc additive manufacturing of Al-Si-Mg aluminum alloy through wire−powder synchronous deposition

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Transactions of Nonferrous Metals Society of China 2025年第3期35卷 701-714页

作者： Yun-fei MENG Qian-xi YU Xu WU Ming GAO Hui CHEN School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced Technologies of Materials Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Owing to the lack of matching commercial welding wires,the development of wire arc additive manufacturing(WAAM)for most aluminum alloys is hindered.A wire-powder synchronous arc additive manufacturing(WPAAM)was proposed to prepare the target Al-Si-Mg aluminum *** on the synchronous deposition of AlSi_(12) wire and pure Mg powder,the deposition width of the WPAAMed thin-wall was increased by 61% compared with that of WAAMed thin-wall using AlSi_(12) wire,and the machining allowance was reduced by 81%.The added Mg powder benefited to form refined equiaxed grains,and reduced the average grain size of the WPAAMed thin-wall to 47.1μm,showing a decrease of 23.8% relatively to that of the WAAMed ***,Mg reacted with Si to form Mg_(2)Si strengthening *** mechanical properties tests showed that the ultimate tensile strength and elongation of the WPAAMed thin-wall increased up to 174.5 MPa and 4.1%,reaching 92% and 60% those of the WAAMed thin-wall,respectively.

关键词： wire arc additive manufacturing wire-powder synchronous deposition Al-Si-Mg aluminum alloy forming accuracy mechanical properties

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Study on the preparation and fretting behavior of bonded oriented MoS_(2)solid lubricant coating

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Friction 2024年第11期12卷 2505-2518页

作者： Liangliang XIONG Mengxue WU Xiaoqiang FAN Minhao ZHU Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The bonded MoS_(2)solid lubricant coating is an effective measure to mitigate the fretting wear of AISI 1045 *** this work,the amino functionalized MoS_(2)was protonated with acetic acid to make the MoS_(2)positively *** directional arrangement of protonated MoS2 in the coating was achieved by electrophoretic deposition under the electric field *** bonded directionally aligned MoS_(2)solid lubricant coating showed high adaptability to various loads and excellent lubrication performance under all three working *** a load of 10 N,the friction coefficient and wear volume of the coating with 5 wt%protonated MoS_(2)decreased by 20.0%and 37.2%compared to the pure epoxy coating,respectively,and by 0.07%and 16.8%than the randomly arranged MoS_(2)sample,*** remarkable lubricating properties of MoS_(2)with directional alignment were attributed to its effective load-bearing and mechanical support,barrier effect on longitudinal extension of cracks,and the formation of a continuous and uniform transfer film.

关键词： bonded solid lubricant coating MoS_(2) fretting oriented alignment

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Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of materials science & Technology 2024年第5期172卷 71-82页

作者： Xiang Su Yuan Lei Yang Chen Hongjie Qu Zhixiang Qi Gong Zheng Xu Liu Henggao Xiang Guang Chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy ***,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening ***,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum *** enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one *** significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T *** thermostable T phase effectively strengthens the matrix by in-hibiting dislocation ***,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high *** finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

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Solvent-free carbon sphere nanofluids towards intelligent lubrication regulation

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Friction 2024年第1期12卷 95-109页

作者： Sheng ZHANG Wen LI Xiaoliang MA Xiaoqiang FAN Minhao ZHU Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

By simply switching the electrical circuit installed on steel/steel contact,the tribological behaviors of nanofluids(NFs)can be regulated in real time,thereby achieving the desired performance of friction reduction and wear ***,solvent-free carbon spherical nanofluids(C-NFs)were successfully prepared for intelligent lubrication regulation.C-NFs with excellent lubrication performance can immediately reduce the coefficient of friction(COF)despite applying a weak electric potential(1.5 V).Moreover,polyethylene glycol 400(PEG400)containing 5.0 wt%C-NFs remained responsive to electrical stimulation under the intermittent voltage application with an average coefficient of friction(ACOF)reduction of 20.8%over *** intelligent lubrication regulation of C-NFs under an external electric field(EEF)mainly depends on the orderly arranged double-electric adsorption film of ion canopy-adsorbed carbon spheres(CSs).The intermittent electrical application can continuously reinforce the adsorption film and its durability for real-time controlling the sliding ***-stimulation-responsive intelligent lubricants provide a new technical support for realizing intelligent stepless control of devices.

关键词： solvent-free carbon spherical nanofluids(C-NFs) intelligent lubrication regulation lubrication performance adsorption film

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C@Ag core‒shell structure as lubricating additives towards high efficient lubrication

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Friction 2024年第9期12卷 1991-2003页

作者： Dong AO Xiaoqiang FAN Minhao ZHU Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Efficient cooperative lubrication can be achieved via the introduction of core‒shell structure lubricant additives with hard core and soft shell,for obtaining the expected anti-wear performance from the structural changes in the friction *** this study,C@Ag microspheres with a core‒shell structure were prepared by the redox method with carbon spheres as the core and Ag nanoparticles as the *** tribological behaviors as base oil(G1830)additive with different concentrations were investigated in *** with base oil,the addition of C@Ag particles at 0.5 wt%can reduce the coefficient of friction(COF)and wear volume(Wv)up to 15.5%and 88%,*** importantly,C@Ag particles provide superior lubrication performance to single additive(like carbon sphere(CS)and Ag nanoparticle).C@Ag core‒shell particles contribute to the formation of tribo-film by melt bonding of flexible Ag and carbon sphere(CS)toward excellent self-repair performance and high-efficiency ***,core‒shell structural nanoparticles with hard-core and soft-shell hold bright future for high-performance lubrication application.

关键词： C@Ag microspheres tribo-film self-repair performance high-efficiency lubrication

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Synergistic enhancement of alkaline hydrogen evolution reaction by role of Ni-Fe LDH introducing frustrated Lewis pairs via vacancy-engineered

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Chinese Chemical Letters 2025年第3期36卷 512-516页

作者： Mianfeng Li Haozhi Wang Zijun Yang Zexiang Yin Yuan Liu Yingmei Bian Yang Wang Xuerong Zheng Yida Deng State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikou 570228China Tianjin Key Laboratory of Composite and Functional Materials Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education)School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy *** article discusses a novel strategy for enhancing the performance of Ni-Fe layered double hydroxide(Ni-Fe LDH)in the alkaline HER by modifying it with a frustrated Lewis acid-base pair(FLP)constructed through vacancy *** study found that the modified Ni-Fe LDH exhibited improved alkaline HER *** functional theory(DFT)calculations demonstrate that the introduction of FLP can activate water and protons more efficiently than monometallic sites,thus reducing the alkaline HER energy barrier and *** HER under alkaline conditions,the Volmer step involves an additional hydrolysis dissociation compared to acidic conditions,which is one of the factors contributing to the slow reaction *** paper demonstrates that FLPs can alter the rate-determining step in alkaline HER from the Volmer step to a step with a lower energy barrier,more suitable for hydrogen *** work provides new insights into the role of FLPs in regulating the mechanism and kinetics of HER and opens a new direction for the design and optimization of LDH-based and other electrocatalysts.

关键词： Ni-Fe LDH Frustrated Lewis acid-base pair Density functional theory The ab initio molecular dynamics The alkaline hydrogen evolution reaction

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Mid-infrared plasmonic silicon quantum dot/HgCdTe photodetector with ultrahigh specific detectivity

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science China(Information sciences) 2023年第4期66卷 286-292页

作者： Yueying CUI Zhouyu TONG Xinlei ZHANG Wenhui WANG Weiwei ZHAO Yuanfang YU Xiaodong PI Jialin ZHANG Zhenhua NI School of Physics and Key Laboratory of MEMS of Ministry of Education Southeast University State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University

Highly sensitive photodetectors operating at mid-infrared（MIR） wavelengths are urgently required for the applications of astronomy, optical communication, security monitoring, and so forth. However,further promoting the sensitivity in conventional MIR devices for a higher detectivity is challenging. Among the potential strategies, integrating localized surface plasmon resonance with MIR semiconductors is a promising approach to developing high-performance optoelectronics. Here we demonstrate a high-sensitivity boron（B）-doped silicon quantum dot（Si-QD）/HgCdTe（MCT） MIR photodetector. Because of plasmon-induced hot-hole tunneling and enhanced light absorption, the hybrid photodetector exhibits a high specific detectivity of ～1.6×10～9cm·Hz1/2·W-1（Jones） and a high-speed response（～224 ns for the rise time and ～580 ns for the fall time） at room temperature. Furthermore, the device achieves high-performance spectral blackbody detection with a peak detectivity of up to 1.6×1011Jones at ～5.8 μm under a cryogenic environment of 77 K, higher than that of bare MCT. This prominent enhancement can be attributed to the further suppression of hot-hole cooling due to a reduced phonon population at low temperatures, which facilitates more efficient hot-carrier extraction and contributes to ultrahigh sensitivity. The plasmonic material-integrated MCT architecture can pave the way for developing high-performance MIR photodetection.

关键词： doped silicon quantum dots HgCdTe localized surface plasmon resonance hot-hole tunneling mid-infrared photodetector

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Construction of ternary PEG200-based DESs lubrication systems via tailoring tribo-chemistry

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Friction 2024年第4期12卷 655-669页

作者： Yuting LI Songyu LAN Yazhou LIU Cheng CAO Zicheng TANG Deyin DENG Fuyuan LIU Hao LI Xiaoqiang FAN Minhao ZHU Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Designing novel lubricants with easily customized structures,devisable compositions,and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications,prolonging machine lifetime,and saving *** eutectic solvents(DESs),which show tunable composition,adjustable structure,easy fabrication,and environmental friendliness,are promising candidates for variable and complicated lubricants *** promote the use of DESs as lubricants,a series of PEG200-based DESs with active heteroatoms were fabricated to tailor the tribological performance via ***,PEG200/boric acid(BA)DES shows optimal lubrication performance by forming tribo-chemical reaction film composited of B2O3,iron oxides,and FeOOH,and PEG200/thiourea(TU)DES displays abrasive wear-reducing property by producing FeS tribo-chemical *** the excellent abrasive wear-resistance of PEG200/TU DES and friction reduction of PEG200/BA DES,ternary PEG200/BA/TU DESs,composited of PEG200/TU DES and PEG200/BA DES,are first *** ternary DESs possess superior wettability and thermal stability,which render them potential *** tests of the ternary DESs demonstrate that synergistic lubrication is achieved by forming a transfer film consisting of FexBy,BN,B2O3,and *** FexBy,BN,and B2O3 increase load bearing of the film,and FeS mitigates severe abrasive *** proposed design philosophy of novel DESs as lubricants opens up a unique realm that is unattainable by traditional DESs lubrication mechanisms and provides a platform to design next-generation DESs lubrication systems.

关键词： deep eutectic solvents(DESs) PEG200/boric acid DES PEG200/thiourea DES ternary DESs synergistic lubrication tribo-chemistry

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