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Science China Materials 2017年第10期60卷 909-917页

作者： shi-kuo li li-Bo Mao Huai-ling Gao Hong-Bin Yao Shu-Hong Yu Center of Chinese Academy of Sciences University of Science and Technology of China Hefei 230026 China

Although remarkable progress has been witnessed in mimicking the nacre-like architecture in laboratory,it remains a great challenge for understanding the unique balancing mechanism of toughness and strength in biological materials. Here,taking advantage of the synergistic effect of different dimensional nanoscale building blocks,we fabricate nacre-like films that reconcile high strength and *** obtained ternary lamellar composite films are constructed by one-dimensional xonotlite nanowires and two-dimensional montmorillonite nanosheets with the assistance of poly（vinyl alcohol）. The ternary composite films show high strength（（241.8±10.2）MPa） and toughness（（5.85±0.46） MJ m^-3）,both of which are higher than that of the single nanofibrillar xonotlite network films or the binary montmorillonite/poly（vinyl alcohol） composite films. The excellent mechanical properties of the nacre-like ternary composite films are aroused by the synergistic toughening mechanism of the different dimensional building blocks. This strategy provides a facile approach to integrate the nacre-like composite films with potential applications in tissue engineering scaffold,strong air barrier coatings,and fire-retardant packing materials.

关键词： artificial nacre mineral nanofibers ternary lamellar,mechanical properties vacuum filtration assembly

A highly sensitive multiple-mode optical thermometer designed in Eu^(2+/3+)and li^(+)co-doped polymorphism compound LaSc_(3)(BO_(3))_(4)

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Journal of Advanced Ceramics 2024年第6期13卷 821-833页

作者： Nan Yang Zhuo li Tingxia Zhou Ziwang Zhang Wen shi Yexiang Tong Jianxin shi School of Chemistry IGCMESun Yat-sen UniversityGuangzhou 510006China MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry IGCMEThe Key Lab of Low-Carbon Chemistry&Energy Conservation of Guangdong ProvinceSun Yat-sen UniversityGuangzhou 510006China

Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be ***,a novel multiple-mode thermometer was designed for the polymorphism LaSc_(3)(BO_(3))_(4):Eu^(2+/3+),li^(+).X-ray diffraction(XRD)patterns revealed a slight transition betweenα-andβ-phases with the concentrations of the dopants,which is further proved by structure refinements and first-principles *** coexistence of Eu^(2+)and Eu^(3+)in the phosphors and their relative percentages were confirmed by X-ray absorption near-edge structure(XANES)*** from appropriate emissions from Eu^(2+)and Eu^(3+)without obvious energy transfer and their opposite changing trends with temperatures under 307 nm excitation,a triple-mode optical thermometer is obtained for this material within the temperature range of 150–450 *** highest sensitivities of 27.65,14.05,and 7.68%·K^(−1)are achieved based on two fluorescence intensity ratio(FIR)modes of Eu^(2+)and Eu^(3+)(5d–4f/^(5)D_(0)–^(7)F_(2,4))and the fluorescence lifetime(FL)mode of Eu^(2+),*** the best of our knowledge,the former is almost the highest in Eu^(2+)and Eu^(3+)co-doped *** results indicate that this material may be used as an excellent multiple-mode optical thermometer.

关键词： phase transition europium(Eu)ions multiple-mode optical thermometer thermal quenching properties fluorescence intensity ratio(FIR) fluorescence lifetime(FL)

Constrained reinforcement learning with statewise projection: a control barrier function approach

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Science China(Information Sciences) 2024年第3期67卷 136-154页

作者： Xinze JIN kuo li Qingshan JIA Department of Automation Tsinghua University

Safety is a critical issue for reinforcement learning(RL), as it may be risky for some actual applications if the learning process involves unsafe exploration. Instead of formulating constraints as expectationbased in constrained RL, considering statewise safety in constrained RL is more meaningful. This work aims to address the issue of safe projection in RL by introducing a control barrier function that inherently learns a safe policy through a set certificate. We seek to analyze some theoretical properties of safe projection in the learning process, including convergence and performance bound, and extend the discussion into ensembles and guided controllers. Moreover, we approach analytical solutions for deterministic and stochastic system dynamics. Experimental results in different tasks show that the proposed method achieves better effects in terms of both performance and safety.

关键词： reinforcement learning safe projection control barrier function

Boosting reversible charging of li-ion batteries at low temperatures by a synergy of propylene carbonate-based electrolyte and defective graphite

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Nano Research 2024年第3期17卷 1491-1499页

作者： Yingqiang Wu Jiao Zhang Jinli liu li Sheng Bo Zhang limin Wang Siqi shi li Wang Hong Xu Xiangming He Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences(CAS)Changchun 130022China China National Quality Supervision and Inspection Center for Industrial Explosive Materials Nanjing University of Science and TechnologyNanjing 210094China School of Materials Science and Engineering Materials Genome InstituteShanghai UniversityShanghai 200444China

Propylene carbonate(PC)-based electrolytes have exhibited significant advantages in boosting the low-temperature discharging of graphite-based li-ion ***,it is still unclear whether they can improve the charging property and suppress lithium *** this topic is challenging due to the problem of electrochemical *** overcome this issue,we introduced graphite with phase *** results show that the pouch-type full batteries using PC-based electrolyte exhibit steady performance over 500 cycles and can be reversibly charged over 30 times at-20℃ with an average Coulombic efficiency of 99.95%,while the corresponding value for the conventional ethylene carbonate(EC)-based electrolyte sample is only 31.20%.This indicates that the use of PC-based electrolyte significantly suppresses lithium plating during low-temperature *** further demonstrate that the improved performance is mainly attributed to the unique solvation structure,where PF-6more anions participate in solvation,leading to the formation of a stable F-rich solid state electrolyte interface on the graphite surface and a lower reduction tendency of li+*** work inspires new ideas for the design of PC-based electrolytes for low-temperature charging and fast-charging batteries.

关键词： lithium-ion batteries graphite propylene carbonate low-temperature charging

Polyimide covalent organic frameworks as efficient solid-state li^(+) electrolytes

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Science China Chemistry 2024年第5期67卷 1647-1652页

作者： Xu liu shi Wang Siqi liu Chengfang liu Xiangchun li Jian Wu Dazhi li shihao Xu Chongyang liu Wen-Yong Lai State Key Laboratory of Organic Electronics and Information Displays(SKLOEID) Institute of Advanced Materials(IAM)School of Chemistry and Life SciencesNanjing University of Posts&TelecommunicationsNanjing 210023China

Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(liBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in liBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance liBs.

关键词： lithium ion batteries(liBs) covalent organic frameworks(COFs) solid-state ion conductors solid-state electrolytes ion conductivity

Matrix orthogonal polynomials,non-abelian Toda lattices,and Bäcklund transformations

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Science China Mathematics 2024年第9期67卷 2071-2090页

作者： shi-Hao li Department of Mathematics Sichuan UniversityChengdu 610064China

A connection between matrix orthogonal polynomials and non-abelian integrable lattices is investigated in this *** normalization factors of matrix orthogonal polynomials expressed using quasideterminants are shown to be the solutions to the non-abelian Toda lattice in semi-discrete and full-discrete ***,with a moment modification method,we demonstrate that the B¨acklund transformation of the non-abelian Toda lattice given by Popowicz(1983)is equivalent to the non-abelian Volterra lattice,whose solutions can be expressed using quasi-determinants as well.

关键词： matrix orthogonal polynomial non-abelian Toda lattice Backlund transformation quasideterminant technique

Constructing the Impossible Differential of Type-II GFN with Boolean Function and Its Application to WARP

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Chinese Journal of Electronics 2024年第1期33卷 80-89页

作者： Jiali shi Guoqiang liU Chao li College of liberal Arts and Sciences National University of Defense Technology Hunan Engineering Research Center of Commercial Cryptography Theory and Technology Innovation State Key Laboratory of Information Security Institute of Information Engineering

Type-Ⅱ generalized Feist el network(GFN) has attracted a lot of attention for its simplicity and high *** differential attack is one of the powerful cryptanalytic approaches for word-oriented block ciphers such as Feistel-like *** deduce the impossible differential of Type-Ⅱ GFN by analyzing the Boolean function in the middle *** main idea is to investigate the expression with the variable representing the plaintext(ciphertext) difference words for the internal state *** adopting the miss-in-the-middle approach,we can construct the impossible differential of Type-Ⅱ *** an illustration,we apply this approach to WARP,a lightweight 128-bit block cipher with a 128-bit key which was presented by Banik et *** SAC *** structure of WARP is a 32-branch Type-Ⅱ ***,we find two 21-round truncated impossible differentials and implement a 32-round key recovery attack on *** the 32-round key recovery attack on WARP,some observations are used to mount an effective *** the advantage of the early abort technique,the data,time,and memory complexities are 2125.69chosen plaintexts,2126.6832-round encryptions,and 2100-bit,*** the best of our knowledge,this is the best attack on WARP in the single-key scenario.

关键词： Ciphers Boolean functions Parallel processing Complexity theory

On Isodual Double Toeplitz Codes

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Journal of Systems Science & Complexity 2024年第5期37卷 2196-2206页

作者： shi Minjia XU li SOLé Patrick Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education School of Mathematical Sciences Anhui University State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences CNRS University of Aix Marseille Centrale Marseille

Double Toeplitz（shortly DT） codes are introduced here as a generalization of double circulant codes. The authors show that such a code is isodual, hence formally self-dual（FSD）. FSD codes form a far-reaching generalization of self-dual codes, the most important class of codes of rate one-half. Self-dual DT codes are characterized as double circulant or double negacirculant. likewise, even binary DT codes are characterized as double circulant. Numerical examples obtained by exhaustive search show that the codes constructed have best-known minimum distance, up to one unit, amongst formally self-dual codes, and sometimes improve on the known values. For q = 2, the authors find four improvements on the best-known values of the minimum distance of FSD codes. Over F4an explicit construction of DT codes, based on quadratic residues in a prime field, performs equally well. The authors show that DT codes are asymptotically good over Fq. Specifically, the authors construct DT codes arbitrarily close to the asymptotic Varshamov-Gilbert bound for codes of rate one half.

关键词： Double circulant codes double Toeplitz codes formally self-dual codes isodual codes

Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

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Journal of Energy Chemistry 2024年第10期97卷 371-378页

作者： Juntao Si Xiaoying li Yixuan li kuo Cao Yiran Zhu Chunhua Chen CAS Key Laboratory of Precision and Intelligent Chemistry Department of Materials Science and Engineering University of Science and Technology of China

The lithium metal anode is hailed as the desired "holy grail" for the forthcoming generation of highenergy-density batteries,given its astounding theoretical capacity and low ***,the formation and growth of dendrites seriously compromise battery life and ***,an yttriastabilized bismuth oxide（YSB） layer is fabricated on the polypropylene（PP） separator,where YSB reacts with li anode in-situ in the cell to form a multi-component composite interlayer consisting of li3Bi,li2O,and *** interlayer can function not only as a redistributor to regulate li+distribution but also as an anion adsorber to increase the li+transference number from 0.37 to 0.79 for suppressing dendrite nucleation and ***,compared with the cell with a baseline separator,those with modified separators exhibit prolonged lifespan in both li/li symmetrical cells and li/Cu ***,the full cells coupled with ultrahigh-loading liFePO4display an excellent cycling performance of 1700 cycles with a high capacity retention of ～80% at 1 C,exhibiting great potential for practical *** work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free li anode and realizing long-lifespan lithium metal batteries.

关键词： Conversion-alloying reaction Dendrite-free lithium metal battery Multifunctional interlayer Separator

Rhodium-catalyzed addition reactions of benzylic C–H bonds to cyclic N-sulfonyl ketimines viaπ-coordination

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Chinese Chemical Letters 2024年第3期35卷 287-291页

作者： Yuntong li Hang shi Department of Chemistry Zhejiang UniversityHangzhou 310027China Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province Department of ChemistrySchool of Science and Research Center for Industries of the FutureWestlake UniversityHangzhou 310030China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China

Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and ***,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic *** this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-*** strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.

关键词： Benzylic deprotonation Cyclic N–sulfonyl ketimines π-Coordination Mannich-type addition Rhodium catalysis