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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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Syntheses of new di-nuclear and tetra-nuclear lanthanide 9-anthracenecarboxylates:Magnetocaloric effect,slow magnetic relaxation and luminescent properties

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Journal of Rare Earths 2024年第6期42卷 1101-1109,I0004页

作者： Xing liu Ruonan Yang Lu Zhang Jian Zhou Chunmei Huang Huahong Zou Zunhong Xiao Chongqing Key Laboratory of Inorganic Functional Materials College of ChemistryChongqing Normal UniversityChongqing401331China Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources(Ministry of Education of China) School of Chemistry and Chemical Engineering of Guangxi Normal UniversityGuilin541004China School of Chemistry and Materials Guizhou Normal UniversityGuiyang550025China

Lanthanide complex-based materials with magnetic and luminescent properties have received a great deal of attention,owing to their importantly potential applications in diverse fields.In this work,the 9-anthracenecarboxylic acid(9-Haca)as bridging ligand was applied in combination with optically activeπ-conjugated 2,4,6-tri(2-pyridyl)-1,3,5-triazine(tptz)to construct a series of new di-nuclear and tetranuclear lanthanide 9-anthracenecarboxylates[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]·0.25H_(2)O(1),[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]·0.5AQ·CH_(3)COOH_(2)H_(2)O[Ln=Sm(2a),Eu(2b),Gd(2c),Tb(2d),Dy(2e),Tm(2f);AQ=9,10-anthracenedione]and[Ln_(4)(9-aca)_(10)(tptz)_(2)(CH3COO)2]·H_(2)O[Ln=Eu(3a),Gd(3b),Dy(3c)].1 displays a di-nuclear centrosymmetric moiety[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]built up from two complex[La(9-aca)_(2)(tptz)]groups bridged by one H_(2)O molecule and two syn-syn-μ2-η1:η1-9-aca-bridging ligands,while 2a-2f are isostructural and co mprise another di-nuclear centrosymmetric moieties[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]based on two complex[Ln(9-aca)_(2)(tptz)(H_(2)O)]groups connected by two syn-syn-μ2-η1:η1-9-aca-bridging ligands,3a-3c are isostructural and show tetra-nuclear centro symmetric moieties[Ln4(9-aca)10(tptz)2(CH3COO)2]containing three types of coordination modes of 9-aca-ligands.The present compounds offer the only examples of lanthanide 9-anthracenecarboxylates decorated by optically active tptz.Magnetic investigations of 2a,2c-2f,and 3b-3c indicate that 3c is typical of slow relaxation of the magnetization,while 2c and 3b show significant magnetocaloric effect(MCE)with the value of-ΔSm of 5.26 J/(kg·K)at 4 K and 15.65 J/(kg·K)at 2 K(ΔH=7 T),respectively.The luminescent properties were also studied and reveal that the characteristic luminescent properties of the 7r-conjugated aromatic ligands are introduced into magnetic lanthanide 9-anthracenecarboxylates,simultaneously exhibiting slow magnetic relaxation(or MCE)and luminescent properties.

关键词： Lanthanide complexes Luminescence Magnetic properties Magnetocaloric effect Slow magnetic relaxation Rare earths

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Atorvastatin, etanercept and the nephrogenic cardiac sympathetic remodeling in chronic renal failure rats

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Journal of Geriatric Cardiology 2024年第4期21卷 443-457页

作者： Jing-Yue XU Zheng-Kai XUE Ya-Ru ZHANG Xing liu Xue ZHANG Xi YANG Tong liu Kang-Yin CHEN Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of CardiologyTianjin Institute of Cardiologythe Second Hospital of Tianjin Medical UniversityTianjinChina

BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia(VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this process.METHODS A total of 48 rats were randomly divided into sham operation group(Sham group), CRF group, CRF + atorvastatin group(CRF + statin group), and CRF + etanercept group(CRF + rhTNFR-Fcgroup). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43(GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent assay.RESULTS Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay,immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + rhTNFR-Fcgroup.CONCLUSIONS In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept could downregulate the expression of TNF-α or inh

关键词： remodeling cardiac inhibited

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High temperature treatment induced production of unreduced 2n pollen in Camellia oleifera

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Horticultural Plant Journal 2024年第3期10卷 879-896页

作者： Hongda Deng Xiaoyu Zhang Song Sheng Yuxun Huang Ziqi Ye Tongyue Zhang Xing liu Zhiqiang Han The Laboratory of Forestry Genetics Central South University of Forestry and TechnologyChangshaHunan 410004China Yuelushan Laboratory ChangshaHunan 410128China Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees of Ministry of Education Central South University of Forestry and TechnologyChangshaHunan 410004China National Forest and Seedling Workstation of Hunan Province The Forestry Department of Hunan ProvinceChangshaHunan 410004China

Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.

关键词： Camellia oleifera Pollen mother cells(PMCs) High temperature Meiosis 2n pollen CoPGX3

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Optimal Initialization and Starting Approach of Synchronous Condenser Integrated Power Grid

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 248-260页

作者： Puyu Wang Xing liu Qingwen Mou Tao Yuan Tianming Gu Hemin Yang Xiao-Ping Zhang Zhengrong Xiang Chunyi Guo School of Automation Nanjing University of Science and TechnologyNanjing 210094China NARI Group Corporation/State Grid EPRI and also with NARI Technology Co.Ltd. Nanjing 211106China School of Engineering University of BirminghamBirminghamB152TTUnited Kingdom State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

Synchronous condensers(SCs)are generally used at the receiving-end stations of ultra-high-voltage direct current(UHVDC)transmission systems due to their strong reactive power support and flexible regulation of reactive power according to the interconnected grids operating conditions.In this paper,different starting control schemes of a SC integrated power grid are investigated providing four main contributions:1)The principle of reactive power support of the SC on the interconnected power grid is analytically studied,providing the establishment of mathematical models.2)Four different starting control schemes are developed for the initialization and SC integration,i.***.in Scheme 1,a preset initial falling speed is directly utilized without initialization;in Scheme 2,a black start sequential control approach with a static frequency converter(SFC)is proposed;in Scheme 3,PI/PD/PID controllers are respectively applied for the excitation device at the speed-falling stage;in Scheme 4,a pre-insertion approach of an energy absorption component with R/L/RL is utilized to suppress the surges at the SC integration instant.3)The dynamic behaviors of four different starting schemes at specific operating stages are evaluated.4)The success rate of SC integration is analyzed to evaluate starting control performance.Performance of the SC interconnected system with four different starting control schemes is evaluated in the timedomain simulation environment PSCAD/EMTDC^(TM).The results prove the superiority of the proposed starting control approach in Scheme 4.

关键词： Black start dynamic behaviors excitation system pre-insertion of energy absorption components starting control schemes static frequency converter(SFC) success rate of integration synchronous condenser(SC)

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High Permeability in Broadband of Co-sputtered [Fe-Fe_(20)Ni_(80)/Cr]_(n) Multilayer Films

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 410-416页

作者：罗创钰 liu xing 王峰李维 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China College of Materials and Chemical Engineering Hezhou UniversityHezhou 542899China

To achieve high microwave permeability in wide-band for the micron-thick magnetic films,[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer structure was proposed by co-sputtering Fe and FeNi to form the magnetic layers and Cr to form the interlayers.The multilayer structure contributes to the high permeability by reducing the coercivity and diminishing out-of-plane magnetization.The maximum imaginary permeability of[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer film reaches a large value of 800 at 0.52 GHz even though its overall thickness exceeds 1μm.Besides,the magnetic resonance frequency of the multilayer film can be modulated from 0.52 to 1.35 GHz by adjusting the sputtering power of Fe from 0 to 86 W,and its bandwidth for μ’’>200(Δf) is as large as 2.0 GHz.The desirable broad Δf of magnetic permeability,which can be well fitted by the Landau-Lifshitz-Gilbert equations,is due to dual magnetic resonances originated from double magnetic phases of Fe and FeNi that are of different saturation magnetization.The micron-thick multilayer films with high permeability in extended waveband are promising candidate for electromagnetic noise suppression application.

关键词： magnetron sputtering multiple magnetic resonance high permeability electromagnetic noise suppression

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MCR-YOLO model for underwater target detection based on multi-color spatial features

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Optoelectronics Letters 2024年第5期20卷 313-320页

作者： liu Peiyu xing Weiwei MA Yixuan School of Software Engineering Beijing Jiaotong UniversityBeijing 100044China

Within the fields of underwater robotics and ocean information processing, computer vision-based underwater target detection is an important area of research. Underwater target detection is made more difficult by a number of problems with underwater imagery, such as low contrast, color distortion, fuzzy texture features, and noise interference, which are caused by the limitations of the unique underwater imaging environment. In order to solve the above challenges, this paper proposes a multi-color space residual you only look once(MCR-YOLO) model for underwater target detection. First, the RGB image is converted into YCb Cr space, and the brightness channel Y is used to extract the non-color features of color-biased images based on improved Res Net50. Then, the output features of three scales are combined between adjacent scales to exchange information. At the same time, the image features integrated with low-frequency information are obtained via the low-frequency feature extraction branch and the three-channel RGB image, and the features from the three scales of the two branches are fused at the corresponding scales. Finally, multi-scale fusion and target detection are accomplished utilizing the path aggregation network(PANet) framework. Experiments on relevant datasets demonstrate that the method can improve feature extraction of critical targets in underwater environments and achieve good detection accuracy.

关键词： underwater image utilizing

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Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

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Journal of Environmental Sciences 2024年第9期143卷 1-11页

作者： xing-xing Qiao Yu-Hang Xu Xiang-Ji liu Sai-Le Chen Zhou Zhong Ya-Feng Li Jian Lü Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

关键词： Titanium dioxide Schwertmannite Fenton reaction Environmental endocrine disruptors Photocatalysis

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In-situ embedded ultrafine Bi_(12)O_(17)Br_(2)nanotubes in MOF-derived hierarchical porous carbon for enhanced photocatalytic CO_(2)conversion to CO

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Journal of Materials Science & Technology 2024年第4期171卷 47-53页

作者： xing Sun Mengxia Ji Yi Zhang Qingzeng xing Zihan liu Nianhua liu Emmanuel Nkudede Huaming Li Sheng Yin Jiexiang Xia School of Chemistry and Chemical Engineering Institute for Energy ResearchJiangsu UniversityZhenjiang 212013China Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Provincial Key Laboratory of Resources Chemistry of Salt LakesQinghai Institute of Salt LakesChinese Academy of SciencesXining 81008China

Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the ef-ficient approaches to boost the photocatalytic CO_(2)conversion efficiency.Herein,ZIF-67-derived porous carbon(PC)material was employed for the construction of PC@ultrafine Bi_(12)O_(17)Br_(2)nanotubes(PC@BOB NTs)composites through a facile solvothermal synthesis in order to optimize the use of excited elec-trons in the BOB NTs.Photoelectrochemical characterization results revealed that the introduction of PC material achieved a faster charge separation rate in the PC@BOB composites,ensuring more photogener-ated electrons participate in the CO_(2)adsorption and activation process.Moreover,the pore structures of ZIF-67-derived PC material provided abundant confined spaces for the enrichment of CO_(2)molecules.Af-ter 5 h of Xenon lamp irradiation,PC@BOB composites exhibited obviously increased photocatalytic CO_(2)reduction activity in the pure water.When the addition amount of PC was 5 wt%,the PC@BOB-2 com-posite showed the highest CO evolution rate of 359.70μmol/g,which was 2.95 times higher than that of the pure BOB NTs.This work provides some independent insights into the applications of Metal-Organic Framework(MOF)-derived hierarchical porous structures to strengthen the CO_(2)enrichment,as well as the excited charge utilization efficiency,thus achieving a high solar-to-fuel conversion efficiency.

关键词： Bi_(12)O_(17)Br_(2)nanotubes Hierarchical porous structure CO_(2)enrichment Charge separation CO_(2)photoreduction

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Oxidation behavior of low-grade vanadiferous titanomagnetite concentrate with high titanium

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Journal of Iron and Steel Research(International) 2024年第2期31卷 329-341页

作者： Jin-sheng liu Zhen-xing xing Gong-jin Cheng Xue-yong Ding Xiang-xin Xue School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina Liaoning Key Laboratory of Recycling Science for Metallurgical Resources Shenyang110819LiaoningChina Innovation Research Institute of Vanadium and Titanium Resource Industry Technology Northeastern UniversityShenyang110819LiaoningChina

In order to clarify the oxidation mechanisms and make better use of the low-grade vanadiferous titanomagnetite concentrate with high titanium(LVTC),the oxidation behavior of LVTC was investigated.The results showed that oxidation degree was achieved within 90 min when temperature was not lower than 700°C,and the main phases of the oxidized LVTC consisted of Fe9TiO15,Fe2O3,CaSiTiO5 and a small amount of Fe2.75Ti0.25O4.Increasing temperature is favorable to the formation of Fe2TiO5.The surface of LVTC gradually becomes rough,with fine particles of needle-like and granular shape appearing on the surface,which finally turn from laminar to creamy,spread out,and are interspersed with many tiny holes.The phase oxidation paths in LVTC were as follows:(1)Fe2.75Ti0.25O4→Fe9TiO15+Fe2O3;(2)Fe2.75Ti0.25O4→Fe2O3+FeTiO3→Fe2TiO5;(3)FeTiO3→Fe2O3+Fe2Ti3O9→Fe2TiO5.LVTC is predominantly mesoporous whether oxidized or not,with the pores mainly distributed in the range of 2–40 nm,and the specific surface area of LVTC decreases significantly with increasing temperature.

关键词： Low-grade vanadiferous titanomagnetite concentrate Oxidation degree Phase transformation Micromorphology Oxidation path Pore structure

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