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Learning to represent code semantics

Science China(Information Sciences) 2025年

作者： Fang LIU Ge LI Qianhui ZHAO Li ZHANG State Key Laboratory of Complex & Critical Software Environment School of Computer Science & Engineering Beihang University Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of Education School of Computer Science Peking University

Code semantic learning serves as the basis of many program analysis tasks. Researchers have paid much effort to build robust and effective code representation models over the years. One line of work focuses on introducing the code structure into the representations. To further improve the robustness of the code representation, approaches based on compiler intermediate representations(IRs) are proposed. However, these IR-based models suffer from heavy computational costs and memory overhead. How to represent program semantics effectively and efficiently still remains a challenge. To this end, we propose EECS, an effective and efficient code semantic representation approach based on compiler IRs and a hybrid attention mechanism. For input representation, to address the unlimited vocabulary size issue in IR, we propose a variable identification strategy to allocate each register variable to a new ID that can represent their relative positions. Besides, we also extract the data flow information among the code blocks. Then we build a hierarchical multi-layer Transformer encoder to capture the data dependency information as well as the code semantics through a hybrid attention mechanism. To enable EECS to learn code semantics and functionality better, we optimize three objectives jointly during the training *** results on three code semantic understanding tasks show that EECS performs better than the state-of-the-art techniques, demonstrating the remarkable capability of EECS on program semantics understanding.

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Current collectors’ effects on the electrochemical performance of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) suspension electrodes for lithium slurry battery

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Green Energy & Environment 2024年第8期9卷 1306-1313页

作者： Linshan Peng Yufei Ren Zhaoqiang Yin Zhitong Wang Xiangkun Wu Lan Zhang CAS Key Laboratory of Green Process and Engineering Beijing Key Laboratory of Ionic Liquids Clean ProcessState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China Hefei University Hefei230601China Institute of Mechanics Chinese Academy of SciencesBeijing100190China Langfang Green Industrial Technology Center Hebei065001China

Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density, while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors (CCs) are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance (Re) between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black (KB) slurry without active material (AM) and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.

关键词： Semi-solid flow battery Slurry electrode Current collector Electronic resistance Carbon coated Al

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On Klein tunneling of low-frequency elastic waves in hexagonal topological plates

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1139-1154页

作者： Yuxin YAO Yuansheng MA Fang HONG Kai ZHANG Tingting WANG Haijun PENG Zichen DENG School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an710072China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian116024Liaoning ProvinceChina

Incident particles in the Klein tunnel phenomenon in quantum mechanics can pass a very high potential *** the concept of tunneling into the analysis of phononic crystals can broaden the application *** this study,the structure of the unit cell is designed,and the low frequency(<1 k Hz)valley locked waveguide is realized through the creation of a phononic crystal plate with a topological phase transition *** defect immunity of the topological waveguide is verified,that is,the wave can propagate along the original path in the cases of impurities and ***,the tunneling phenomenon is introduced into the topological valley-locked waveguide to analyze the wave propagation,and its potential applications(such as signal separators and logic gates)are further explored by designing phononic crystal *** research has broad application prospects in information processing and vibration control,and potential applications in other directions are also worth exploring.

关键词： topological metamaterial elastic wave Klein tunneling valley-locked waveguide

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AMCheX: Accurate Analysis of Missing-Check Bugs for Linux Kernel

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Journal of Computer Science & Technology 2021年第6期36卷 1325-1341页

作者： Ying-Jie Wang Liang-Ze Yin Wei Dong Key Laboratory of Software Engineering for Complex Systems College of Computer Science National University of Defense TechnologyChangsha 410073China

The Linux kernel adopts a large number of security checks to prevent security-sensitive operations from being executed under unsafe *** a security-sensitive operation is unchecked,a missing-check issue *** check is a class of severe bugs in software programs especially in operating system kernels,which may cause a variety of security issues,such as out-of-bound accesses,permission bypasses,and privilege *** to the lack of security specifications,how to automatically identify security-sensitive operations and their required security checks in the Linux kernel becomes a challenge for missing-check *** this paper,we present an accurate missing-check analysis method for Linux kernel,which can automatically infer possible security-sensitive ***,we first automatically identify all possible security check functions of *** according to their callsites,a two-direction analysis method is leveraged to identify possible security-sensitive operations.A missing-check bug is reported when the security-sensitive operation is not protected by its corresponding security *** have implemented our method as a tool,named AMCheX,on top of the LLVM(Low Level Virtual Machine)framework and evaluated it on the Linux *** reported 12 new missing-check bugs which can cause security *** of them have been confirmed by Linux maintainers.

关键词： security check function security-sensitive operation program analysis missing-check

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Prescribed-Time Nash Equilibrium Seeking for Pursuit-Evasion Game

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1518-1520页

作者： Lei Xue Jianfeng Ye Yongbao Wu Jian Liu D.C.Wunsch Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of EducationNanjing 210096 School of Automation Southeast UniversityNanjing 210096China Department of Electrical and Computer Engineering Missouri University of Science and TechnologyRollaMO 65409 USA IEEE

Dear Editor,This letter is concerned with prescribed-time Nash equilibrium(PTNE)seeking problem in a pursuit-evasion game(PEG)involving agents with second-order *** order to achieve the prior-given and user-defined convergence time for the PEG,a PTNE seeking algorithm has been developed to facilitate collaboration among multiple pursuers for capturing the evader without the need for any global ***,it is theoretically proved that the prescribedtime convergence of the designed algorithm for achieving Nash equilibrium of ***,the effectiveness of the PTNE method was validated by numerical simulation results.A PEG consists of two groups of agents:evaders and *** pursuers aim to capture the evaders through cooperative efforts,while the evaders strive to evade *** is a classic noncooperative *** has attracted plenty of attention due to its wide application scenarios,such as smart grids[1],formation control[2],[3],and spacecraft rendezvous[4].It is noteworthy that most previous research on seeking the Nash equilibrium of the game,where no agent has an incentive to change its actions,has focused on asymptotic and exponential convergence[5]-[7].

关键词： seeking prescribed convergence

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Smart ionic liquid/water mixture system with dual stimuli-response to temperature and CO_(2)

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Nano Research 2023年第3期16卷 4152-4159页

作者： Xiaoqing Yuan Ju Liu Jingyu Qin Weili Ma Guangyong Liu Yanlei Wang Hongyan He Beijing Key Laboratory of Ionic Liquids Clean Process State Key Laboratory of Multiphase Complex SystemsCAS Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China

Stimuli-responsive materials have important applications in chemistry and chemical ***,we synthesized five different polyetheramine-fatty acids(PEFA)ionic liquids(ILs),possessing the dual stimuli-responsive ability to temperature and CO_(2).These PEFA ILs have reversible lower critical solution temperature(LCST)phase behavior over a wide temperature range of 37-91℃,and reversible heterogeneous-homogeneous phase transition towards the addition and removal of CO_(2).Furthermore,the droplet size of the IL-water mixture system increased from 6.5 to 21.0 nm as the temperature increased from 25 to 56℃,and then recovered to 6.5 nm when the temperature decreased to 25℃.The addition and removal of CO_(2)also reversibly modulated the droplet size of the *** from nuclear magnetic resonance(NMR)and Fourier transform infrared(FTIR)spectra further showed that the temperature-dependent conformation of polyether amine chain in the cation dominates the temperature response,while the reversible formation of bicarbonate and fatty acids(FA)from CO_(2)and anion controls the CO_(2)-based reversible phase *** simulations revealed a microscopic response mechanism of the IL-water system to temperature and CO_(2),and a synergistic effect between the dual stimuli of temperature and CO_(2).These findings may provide a basis for the rational design and understanding of ILs-based stimuli-responsive materials and nanoreactors.

关键词： stimuli-responsive ionic liquids phase transitions temperature CO_(2)

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Liquid-phase esterification of methacrylic acid with methanol catalyzed by cation-exchange resin in a fixed bed reactor:Experimental and kinetic studies

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Chinese Journal of Chemical engineering 2023年第6期58卷 1-10页

作者： Junyang Liu Luming Wang Yuhang Bian Chunshan Li Zengxi Li Jie Li School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Beijing Key Laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Langfang Technological Center of Green Industry Langfang 065801China

The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed *** reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain *** measurement data were regression with the pseudo-homogeneous(P-H),Eley-Rideal(E-R),and Langmuir-Hinshelwood(L-H)heterogeneous kinetic *** adsorption experiments were implemented to gain the adsorption equilibrium constants of four *** the above three models,the L-H model exhibited the best fitting *** stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h *** structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis(TG),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)and so on.

关键词： Kinetics Esterification Methyl methacrylate Cation-exchange resin Fix bed reactor

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Superior triethylamine-sensing properties based on SnO2 hollow nanospheres synthesized via one-step process

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Progress in Natural Science:Materials International 2024年第4期34卷 682-689页

作者： Mingyue Xu Shu Yan Zia Ur Rehman Jianhua Hou Liangyun Zhai Shengjie Zhu Chuanbao Cao Wanfeng Xie Junyu Zhong Jun Yang State Key Laboratory of Bio-fibers and Eco-textiles School of Electronics and Information College of Materials Science and Engineering College of Chemistry and Chemical Engineering Qingdao University College of Environmental Science and Engineering Yangzhou University State Key Laboratory of Chemical Safety SINOPEC Research Institute of Safety Engineering Co. Ltd. National Registration Center for Chemicals Ministry of Emergency Management Research Center of Materials Science Beijing Institute of Technology State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences

Due to serious harm of triethylamine（TEA） to environmental safety and human health, it is significant to synthesize gas-sensitive materials with high performance for TEA detection. However, it is still a challenge to achieve high-sensitivity detection of TEA at low temperature for a sensor synthesized through an economical and efficient method. In this work, hollow-structured SnO2（HS-SnO2） nanospheres have been fabricated by a facile, low-cost hydrothermal method in one step, which exhibit superior TEA-sensing properties, including not only ultrahigh response（127.75） for 100 ppm TEA, good selectivity, but also fast response and recovery time（17/28 s）, low detection threshold（1 ppm） and robust stability at a relatively low optimum operational temperature of 225°*** excellent gas-sensitizing performances are ascribed to porous hollow structures with rich oxygen vacancies that provide abundant active sites for raising O2adsorption and reaction of TEA and oxygen species. This work offers an effective and economical strategy for fabricating high-performance TEA sensors for industrial applications.

关键词： Hollow-structured SnO2 nanospheres TEA High response Gas sensors

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Theoretical analysis of surface waves in piezoelectric medium with periodic shunting circuits

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1287-1304页

作者： Youqi ZHANG Rongyu XIA Jie XU Kefu HUANG Zheng LI State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055Guangdong ProvinceChina

The investigations of surface waves in the piezoelectric medium bring out great possibility in designing smart surface acoustic wave(SAW)*** is important to study the dispersion properties and manipulation mechanism of surface waves in the semi-infinite piezoelectric medium connected with periodic arrangement of shunting *** this study,the extended Stroh formalism is developed to theoretically analyze the dispersion relations of surface waves under different external *** band structures of both the Rayleigh wave and the Bleustein-Gulyaev(BG)wave can be determined and manipulated with proper electrical boundary ***,the electromechanical coupling effects on the band structures of surface waves are discussed to figure out the manipulation mechanism of adjusting electric *** results indicate that the proposed method can explain the propagation behaviors of surface waves under the periodic electrical boundary conditions,and can provide an important theoretical guidance for designing novel SAW devices and exploring extensive applications in practice.

关键词： metamaterial phononic crystal surface wave piezoelectricity electromechanical coupling Stroh formalism

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Relaxed Stability Criteria for Time-Delay systems:A Novel Quadratic Function Convex Approximation Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 996-1006页

作者： Shenquan Wang Wenchengyu Ji Yulian Jiang Yanzheng Zhu Jian Sun College of Electrical and Electronic Engineering Changchun University of TechnologyChangchun 130012China the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China Key Laboratory of Complex Systems Intelligent Control and Decision Beijing Institute of TechnologyBeijing 100081China

This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying *** introducing two adjustable parameters and two free variables,a novel convex function greater than or equal to the quadratic function is constructed,regardless of the sign of the coefficient in the quadratic *** developed lemma can also be degenerated into the existing quadratic function negative-determination(QFND)lemma and relaxed QFND lemma respectively,by setting two adjustable parameters and two free variables as some particular ***,for a linear system with time-varying delays,a relaxed stability criterion is established via our developed lemma,together with the quivalent reciprocal combination technique and the Bessel-Legendre *** a result,the conservatism can be reduced via the proposed approach in the context of constructing Lyapunov-Krasovskii functionals for the stability analysis of linear time-varying delay ***,the superiority of our results is illustrated through three numerical examples.

关键词： Equivalent reciprocal combination technique quadratic function convex approximation approach stability timevarying delay

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