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Acceptor-Type Singlet Fission Material Based on Strong Absorption Tetracyanothienoquinoid Skeleton

CCS Chemistry 2024年第9期6卷 2142-2149页

作者： Senhao Wang xiang-yang liu Mengfan Zhang Long Wang Ganglong Cui Hongbing Fu Jiannian Yao Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024 College of Chemistry and Material Science Sichuan Normal UniversityChengdu 610068 Key Laboratory of Theoretical and Computational Photochemistry Ministry of EducationCollege of ChemistryBeijing Normal UniversityBeijing 100875 Beijing Key Laboratory for Optical Materials and Photonic Devices Department of ChemistryCapital Normal UniversityBeijing 100048 Beijing National Laboratory for Molecules Science(BNLMS) Key Laboratory of PhotochemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190

The practical efficiency of singlet fission(SF)-based photovoltaic devices is still far from satisfactory due to the limited scope of SF materials suitable for device application and the scarcity of schemes available for triplet *** SF materials identi-fied to date are typically electron donors while acceptor-type SF materials remain largely ***,the combination of a conventional electron donor and SF-active electron acceptor could circumvent the competitive energy transfer channel and better play the unique advantages of the SF process,which might be an adequate alternative for practical *** this work,we presented a new acceptor-type SF material based on a tetracyanothienoquinoid *** a quinoid skeleton exhibited strong absorption,ultrafast SF process,and excellent *** transient spectroscopy and multireference calculations(XDWCASPT2),the SF dynamics were examined featuring the rapid generation and subsequent annihilation and/or partial dissociation of multiexciton ***,our results not only provide a robust acceptor-type SF material but also suggest an adequate donor–acceptor alternative for SF-based solar cells,which could pave the way for the practical application of such a potential process.

关键词： singlet fission acceptor quinoidal skeleton mutiexciton state multireference calculation transient spectroscopy

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Bioinspired design of integral molded Janus silk fibroin-MXene evaporator for efficient solar vapor generation

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Nano Research 2024年第4期17卷 2824-2835页

作者： Ling-Qing Kong Zhi-Cheng Zeng Guang-Zong Min Zhao-Hui Meng Guo-Qing Meng Xiao-Xiao Guo Nai-Bo Lin xiang-yang liu The Higher Educational Key Laboratory for Biomedical Engineering of Fujian Province Research Center of Biomedical Engineering of XiamenDepartment of BiomaterialsCollege of MaterialsXiamen UniversityXiamen 361005China The State Key Laboratory of Marine Environmental Science(MEL) College of Ocean and Earth SciencesXiamen UniversityXiamen 361005China

Solar vapor generation is a promising sustainable technology that uses solar distillation to produce fresh water from seawater and wastewater,helping relieve global water resource ***,inspired by naturally grown integrally molded mulberry leaves with a Janus hydrophilic and hydrophobic structure,a novel,simple,and efficient integrated molding method is proposed to break through the limitations of the traditional split manufacturing strategy and realizes the integrated formation of Janus *** on the spontaneous sedimentation characteristics of MXene in silk fibroin solution and its regulation of mesoscopic structure and hydrophilicity of silk fibroin,layered structures with different compositions and hydrophilicities were obtained in one ***,ethanol and glutaraldehyde were added to construct a physical crystallization-chemical crosslinking dual stabilization structure in silk *** evaporator has the evaporation rate of 3.07 kg·m^(-2)·h^(-1) and the efficiency of 86.8%under 1 sun and maintains high evaporation performance under various extreme test conditions including vigorous washing,repeated compression,and high-intensity ultraviolet(UV)***,the evaporator performs well in practical application scenarios,its evaporation rate in the simulated Dead Sea seawater exceeds 2.13 kg·m^(-2)·h^(-1),and more than 99.9%of the salt,heavy metal ions,oil pollution,and dyes are purified.

关键词： silk fibroin MXene bioinspired integrated molding Janus structure solar vapor generation

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光和热驱动金催化邻炔基酚与芳基重氮盐的反应:两种机制相似性和差异性的理论研究

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Chinese Journal of Chemical Physics 2024年第1期37卷 87-99,I0036-I0092,I0118页

作者：金蕊郭昕怡彭灵雅刘向洋方维海崔刚龙北京师范大学化学学院理论及计算光化学教育部重点实验室北京100875 四川师范大学化学与材料科学学院成都610068

实验上发现,邻炔基酚与芳基重氮盐在热催化和光催化条件下反应可生成不同的产物,然而反应机理尚不清晰.本文采用MSCASPT2和密度泛函理论方法研究了热和光驱动反应的催化机理.结果表明,热催化和光催化反应的初始历程相同,都是在HCO3-协... 详细信息

实验上发现,邻炔基酚与芳基重氮盐在热催化和光催化条件下反应可生成不同的产物,然而反应机理尚不清晰.本文采用MSCASPT2和密度泛函理论方法研究了热和光驱动反应的催化机理.结果表明,热催化和光催化反应的初始历程相同,都是在HCO3-协助下由Au(Ⅰ)催化剂和邻炔基酚反应得到乙烯基Au(Ⅰ)中间体.在此过程中,Au(l)催化剂与邻炔基酚反应克服14.8 kcal/mol的能垒生成结构扭曲的配合物,此时邻炔基酚的C≡C三键被活化.随后,乙烯基Au(Ⅰ)中间体和芳基重氮盐形成复合物,热催化和光催化反应开始分叉.在黑暗条件下,反应克服15.7 kcal/mol的能垒后生成最终的热催化产物,此时芳基重氮盐的末端N原子直接与乙烯基Au(Ⅰ)中间体的C原子成键.在光照条件下,复合物首先弛豫到激发单重态,经9.8×10^(9)s^(-1)的高效系间窜跃过程衰变到T_(1)态.在T_(1)态,克服7.8 kcal/mol的能垒完成脱氮反应,产生与乙烯基Au(Ⅰ)中间体的Au原子具有相互作用的芳基自由基,随后发生系间窜跃过程到达基态.在基态形成最终的光催化产物.本研究为理解Au(Ⅰ)催化剂与芳基重氮盐的热催化和光催化反应提供了重要的机理见解,发现了无辐射跃迁在光催化反应中的关键作用.

关键词：光氧化还原催化过渡金属配合物密度泛函理论反应机理 Au(Ⅰ)催化剂光物理芳基重氮盐邻炔基酚

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Shape-controlled syntheses of rhodium nanocrystals for the enhancement of their catalytic properties

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Nano Research 2015年第1期8卷 82-96页

作者： Shuifen Xie xiang yang liu Younan Xia Research Institute for Soft Matter and Biomimetics and Department of Physics Xiamen University Xiamen Fujian 361005 China The Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory University and School of Chemistry and Biochemistry and School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta Georgia 30332 United States

Rhodium （Rh） is a critical component of many catalysts for a variety of chemical transformation processes. Controlling the shape of Rh nanocrystals offers an effective route to the optimization of their catalytic performance owing to a close correlation between the catalytic activity/selectivity and the surface atomic structure. It also helps to substantially reduce the loading amount and thus achieve a sustainable use of this scarce and precious metal. In this review article, we focus on recent progress in the shape-controlled synthesis of Rh nanocrystals with the goal of enhandng their catalytic properties. Both traditional and newly- developed synthetic strategies and growth mechanisms will be discussed, including those based on the use of surface capping agents, manipulation of reduction kinetics, control of surface diffusion rate, management of oxidation etching, and electrochemical alteration. We also use two examples to highlight the unique opportunities offered by shape-controlled synthesis for enhancing the use of this metal in catalytic applications. The strategies can also be extended to other precious metals in an effort to advance the production of cost-effective catalysts.

关键词： Rhodium nanocrystals shape control material synthesis surface structure catalysis

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Paradigm Shift in Natural Language Processing

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Machine Intelligence Research 2022年第3期19卷 169-183页

作者： Tian-xiang Sun xiang-yang liu Xi-Peng Qiu Xuan-Jing Huang School of Computer Science Fudan UniversityShanghai 200438China Shanghai Key Laboratory of Intelligent Information Processing Fudan UniversityShanghai 200438China

In the era of deep learning, modeling for most natural language processing (NLP) tasks has converged into several mainstream paradigms. For example, we usually adopt the sequence labeling paradigm to solve a bundle of tasks such as POS-tagging, named entity recognition (NER), and chunking, and adopt the classification paradigm to solve tasks like sentiment analysis. With the rapid progress of pre-trained language models, recent years have witnessed a rising trend of paradigm shift, which is solving one NLP task in a new paradigm by reformulating the task. The paradigm shift has achieved great success on many tasks and is becoming a promising way to improve model performance. Moreover, some of these paradigms have shown great potential to unify a large number of NLP tasks, making it possible to build a single model to handle diverse tasks. In this paper, we review such phenomenon of paradigm shifts in recent years, highlighting several paradigms that have the potential to solve different NLP tasks.

关键词： Natural language processing pre-trained language models deep learning sequence-to-sequence paradigm shift

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Thermodynamic Research on Precipitates in Low Carbon Nb-Microalloyed Steels Produced by Compact Strip Production

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Journal of Materials Science & Technology 2007年第2期23卷 267-272页

作者： Song xiang Guoquan liu yang LI Changrong LI Andong WANG School of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Microalloying element Nb in low carbon steels produced by compact strip production （CSP） process plays an important role in inhibiting recrystallization, decreasing the transformation temperature and grain *** decreasing the rolling temperature, dislocations can be pinned by carbonitrides and the strength is increased. Based on the two sublattice model, with metal atom sublattice and interstitial atom sublattice,a thermodynamic model for carbonitride was established to calculate the equilibrium between matrix and carbonitride. In the steel produced by CSP, the calculation results showed that the starting temperature of precipitation of Ti and Nb are 1340℃ and 1040℃, respectively. In the range of 890-950℃, Nb rapidly precipitated. And the maximum of the atomic fraction of Nb in carbonitride was about 0.68. The morphologies and energy spectrum of the precipitates showed that （NbTi）（CN） precipitated near the dislocations. The experiment results show that Nb rapidly precipitated when the temperature was lower than 970℃, and the atomic fraction of Nb in carbonitride was about 60%-80%. The calculation results are in agreement with the experiment data. Therefore the thermodynamic model can be a useful assistant tool in the research on the precipitates in the low carbon steels produced by CSP.

关键词： Compact strip production Niobium Low carbon microalloyed steels Precipitation Thermodynamic model

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A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

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Acta Mechanica Solida Sinica 2024年第1期37卷 166-180页

作者： Zongxing liu xiang yang Jun liu School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China COMAC Shanghai Aircraft Design and Research Institute Shanghai 201210China

To reduce the damage of the pressurizing panel structure of a fuselage caused by an explosion at the“least risk bomb location”in an aircraft structure,a new pre-separation panel structure was designed to resist blast ***,the dynamic strain response and morphology of impact damage of the new pre-separation panel were measured in an impact damage ***,the commercial software LS-DYNA was used to calculate the propagation of the blast shock wave,and the results were compared with empirical equations to verify the rationality of the numerical calculation ***,the fluid–structure coupling method was used to calculate the damage process of the pre-separation panel structure under the impact of an explosion wave and an impact *** calculated results were in good agreement with the test results,which showed the rationality of the calculation method and the *** residual strength of the damaged pre-separation panel was significantly higher than that of the original damaged *** results show that the new pre-separation panel structure is reasonable and has certain significance for guiding the design of plenum chambers with strong resistance to implosion for aircraft fuselages.

关键词： Pre-separation panel structure Explosive response Residual strength Aircraft plenum chamber Least risk bomb location

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A Novel Diamine,4'-Phenyiphenyi 4-(3",5"-Diaminobenzoyioxy)-benzoate and Longer Side-chain Polyimide

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Chinese Chemical Letters 2005年第9期16卷 1151-1154页

作者： Jin yang Li Gang REN xiang yang liu Yi GU State Key Laboratory of Polymeric Materials Engineering College of Polymer Science and Engineering Sichuan University Chengdu 610065

This is a part of our systematic research work on polyimides with mesogenic unit side chain. In this study, a new 4＇-phenylpbenyl 4-（3＂,5＂-diaminobenzoyloxy）benzoate and polyimide were synthesized, and characterized by FTIR, ^1H-NMR, inherent viscosity, mechanical properties, and solubility measurements. The diamine composed with mesogenic unit aryl ester groups and bipbenyl group with longer L/D ratio, was synthesized by two key steps. Firstly, the hydroxy group of 4-hydroxybenzoic acid was protected by acetoxy group for avoiding self- polymerization of 4-hydroxybenzoic acid, and then selectively hydrolyzed after esterification of carboxyl. Secondly, a selective catalysis hydrogenation was adopted to prevent the aryl ester from deoxidation. Based on this diamine, a novel polyimide was prepared by polycondensation of 4＇-phenylphenyl 4-（3＂, 5＂-diaminobenzoyloxy）benzoate and 4-aminophenyl ether（ODA） with 4, 4＇-oxydiphthalic anhydride（ODPA） in N-methyl-2-pyrrolidone （NMP）. The resulting polyimide with longer side chain showed better solubility and more regular structure. Its inherent viscosity is lower than that without side chains, but its modulus and strength not only maintained, even improved.

关键词： Polyimide film materials side-chain synthesis

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Synthesis of a Novel Diamine 4-[(4'-Butoxyphenoxy)carbonyl]phenyl-3",5"-diaminobenzoate and Corresponding Polyimides

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Chinese Chemical Letters 2006年第11期17卷 1511-1514页

作者： Li Gang REN xiang yang liu Yi GU State Key Laboratory of Polymeric Materials Engineering College of Polymer Science and Engineering Sichuan University Chengdu 610065

A novel diamine 4-[（4＇-butoxyphenoxy）carbonyl]phenyl-3＂,5＂-diaminobenzoate （BCDA） was synthesized from 4-butoxyphenol, 4-hydroxybenzoic acid and 3,5-dinitrobenzoic acid through four main intermediates, and a series of polyimides were also synthesized. All the intermediates and the final product were characterized by FTIR and 1H-NMR. The key step in synthesis route is selective hydrolyzation of two ester groups in 4-butoxyphenyl-4＇-acetoxybenzoate, by adjusting the reaction temperature and the concentration of ammonia, shorteding the reaction time. The properties of the novel polyimides, such as the aggregation structures, glass transition temperature, solubility and the pretilt angles, were carded out.

关键词： Synthesis polyimides side chain alignment film.

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Structural Optimization of Polyimide Foam via Composition with Hyperbranched Polymer Modified Fluorinated Carbon Nanotubes

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Chinese Journal of Polymer Science 2023年第1期41卷 117-128页

作者： Jian liu Zhuang Nie Rui Qin An-Ping Ou Tao Zhang Xu Wang xiang-yang liu College of Polymer Science and Engineering State Key Laboratory of Polymer Material and EngineeringSichuan UniversityChengdu610065China Zhejiang Key Laboratory of Marine Materials and Protective Technologies Key Laboratory of Marine Materials and Related TechnologiesCASNingbo315000China

The key to improve the foam’s performance is to optimize the cellular structure and its bulk-material ***,the hyperbranched polymer modified fluorinated multi-walled carbon nanotube(HPMCNT-F)based on the nucleophilic reactions of MCNT-F was successfully prepared and used to composite with PI *** pristine MCNT shows a poor dispersity and weak interfacial interaction with PI *** HPMCNT-F exhibits an excellent dispersity and effectively forms covalent/non-covalent interaction with PI matrix due to the surface-structure engineering,resulting in the enhancement of the PI ***,HPMCNT-F works as a heterogeneous nucleation agent in PI foam to optimize the cellular *** enhancement of PI bulk and the optimizing of cellular structure result in the increase of compressive special strength of composite foam by 58.9%with a low loading of 1.6 wt%***,the hyperbranched polymers effectively prevent the thermal conduction among HPMCNT-F,and the isolated MCNTs effectively block thermal radiation through absorption and reflection the infrared ***,the thermal conductivity was reduced by 8.0%simultaneously.

关键词： Foams Nanocomposites Mechanical properties Thermal properties

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