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Science China Chemistry 2025年

作者： Jun-Qiang Chen qiao-Hong li Qin-Long Hong Ping Shao Hai-Xia Zhang Jian Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Single-atom catalyst has garnered widespread attention to mimic mature enzymes due to its well-defined atomic structure and coordination environments. However, since the carbon–carbon（C–C） coupling reactions require synergistic catalysis of multiple sites, single-atom catalysts suffer from insufficient active sites and unclear reaction mechanisms. Controlling the reaction intermediates in a precisely targeted pocket through careful metal–organic cage design is therefore crucial. Here, we prepare a tetrahedral [Cu6L4]-type boron–imidazolate cage integrating highly active Cu sites and optimized cavity, which exhibits enzyme like specific catalytic performance in electrochemical CO2reduction reaction（CO2RR） to enhance the selectivity of *** analyses and computational calculations suggest that the single Cu site together with neighboring boron–imidazolate ligands provides suitably synergistic effects that enable the energetically favorable formation of an *COCHO intermediate, a key step determining selectivity. As a result, the [Cu6L4]-type cage of BIC-145 achieves a Faradaic efficiency of 28% for C2H4maintaining an average current density of -3.54 mA cm-2over a 5-hour electrolysis period. This work represents the first example for studying single-metal site catalysts with ultra-low coordination numbers through the rational design of metal–organic cages.

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基于UDEC的岩脉侵入角度对隧道安全影响分析

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山西建筑 2025年第1期51卷 164-167页

作者：王毅李乔四川省交通建设集团有限责任公司四川成都610000 江苏丰县221700

为探究岩脉侵入角度对隧道开挖的影响,文章以泸石高速石棉隧道开挖时地层遭遇不同角度岩脉侵入为工程背景,通过UDEC离散元计算,总结岩脉侵入角度对隧道开挖的影响,给出有效处理措施,并得出以下结论:岩脉和被侵入岩体界面易发生塑性滑移... 详细信息

为探究岩脉侵入角度对隧道开挖的影响,文章以泸石高速石棉隧道开挖时地层遭遇不同角度岩脉侵入为工程背景,通过UDEC离散元计算,总结岩脉侵入角度对隧道开挖的影响,给出有效处理措施,并得出以下结论:岩脉和被侵入岩体界面易发生塑性滑移,隧道开挖后岩脉区围岩变形最大,且岩脉区围岩有开裂、滑移和隆起现象,围岩变形随角度的减小而减小。边墙与仰拱连接处轴力、剪力、弯矩均最大,安全系数最小,三种工况均在0.3左右。衬砌轴力、剪力的最大值随角度减小而增大,弯矩受角度的影响较小。岩脉区域的安全系数在向着岩脉倾斜方向更小。岩脉侵入区域隧道开挖应采用岩脉区域局部注浆、封闭仰拱、增大衬砌厚度三种方法来加固围岩和提高衬砌承载能力。

关键词：隧道工程侵入岩脉 UDEC离散元处置措施

Upper bound of the third edge-connectivity of graphs

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Science China Mathematics 2005年第3期48卷 360-371页

作者： WANG Yingqian li qiao Department of Mathematics Zhejiang Normal University Jinhua 321004 China Department of Applied Mathematics Shanghai Jiaotong University Shanghai 200030 China

Let G be a simple connected graph of order n ≥ 6. The third edge-connectivity of G is defined as the minimum cardinality over all the sets of edges, if any, whose deletion disconnects G and every component of the resulting graph has at least 3 vertices. In this paper, we first characterize those graphs whose third-edge connectivity is well defined,then establish the tight upper bound for the third edge-connectivity.

关键词： third edge-connectivity, upper bound.

ELECTRIC FIELD EFFECTS ON YOUNG'S MOLULUS OF NANOWIRES

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Acta Mechanica Solida Sinica 2009年第6期22卷 511-523页

作者： Xiaojing Zheng li qiao Key Laboratory of Mechanics on Western Disaster and Environment Ministry of Education PRC Department of Mechanics and Engineering Science College of civil Engineering and Mechanics Lanzhou University Lanzhou Gansu 730000 China

As an important component of nanodevices and nanomachine constructions, the mechanical performance of nanowires （NWs） has been a subject of intense research efforts due to gaining relevance in controlling functionality of nanoelectromechanical systems （NEMS）; meanwhile, one of the characteristics of the NEMS is the dependence of the functionality of the systems upon the applied electric field. The study of the electric effects on the Young＇s modulus of nanostructures is of certain usefulness in the design of NEMS and the precise measurement of mechanical properties of one-dimensional nanostructures. This paper reviews the origin of the size-dependence of the elastic property of NWs and the factors influencing the discrepancies and inconsistencies in the measured values of the Young＇s modulus for the NW, besides the surface effects, nonlinear effects, the electromechanical coupling effects as a possible effect responsible for the differences in quantitative and qualitative performance of the measured Young＇s modulus for the NWs versus the diameter are clarified.

关键词： nanowires Young's modulus molecular dynamics simulations continuum mechanics theory electric effects

Impurity effect as a probe for the pairing symmetry of graphene-based superconductors

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Frontiers of physics 2021年第4期16卷 205-211页

作者： Yuan-qiao li Tao Zhou College of Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China Guangdong–Hong Kong Joint Laboratory of Quantum Matter Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

We study theoretically the single impurity effect on graphene-based *** different pairing symmetries are *** in-gap resonant peaks are found near the impurity site for the d+id pairing symmetry and the p+ip pairing symmetry when the chemical potential is *** the chemical potential decreases,the in-gap states are robust for the d+id pairing symmetry while they disappear for the p+ip pairing *** in-gap peaks are absent for the fully gapped extended s-wave pairing symmetry and the nodal f-wave pairing *** existence of the ingap resonant peaks can be explained well based on the sign-reversal of the superconducting gap along different Fermi pockets and by analyzing the denominator of the *** of the features may be checked by the experiments,providing a useful probe for the pairing symmetry of graphene-based superconductors.

关键词： impurity effect graphene superconductivity

Fault tolerant navigation method for satellite based on information fusion and unscented Kalman filter

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Journal of Systems Engineering and Electronics 2010年第4期21卷 682-687页

作者： Dan li Jianye liu li qiao Zhi Xiong School of Electrical Engineering and Information Anhui University of Technology Maanshan 243002 P. R. China Navigation Research Center Nanjing University of Aeronautics and Astronautics Nanjing 210016 P. R. China

An effective autonomous navigation system for the integration of star sensor,infrared horizon sensor,magnetometer,radar altimeter and ultraviolet sensor is *** requirements of the integrated navigation system manager make optimum use of the various navigation sensors and allow rapid fault detection,isolation and *** normal full fusion feedback method of federated unscented Kalman filter（UKF） cannot meet the needs of *** a no-reset feedback federated Kalman filter architecture is developed and used in the autonomous navigation *** minimal skew sigma points are chosen to improve the calculation *** results are presented to demonstrate the advantages of the *** advantages include improved failure detection and correction,improved computational efficiency,and ***,its＇ accuracy is higher than that of the full fusion feedback method.

关键词： autonomous navigation information fusion unscented Kalman filter(UKF) fault detection.

Efficient schedulability analysis for mixed-criticality systems under deadline-based scheduling

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Chinese Journal of Aeronautics 2014年第4期27卷 856-866页

作者： Chen Yao li qiao li Zheng Xiong Huagang School of Electronic and Information Engineering Beihang University

Safety-critical avionics systems which become more complex and tend to integrate multiple functionalities with different levels of criticality for better cost and power efficiency are subject to certifications at various levels of rigorousness. In order to simultaneously guarantee temporal constraints at all different levels of assurance mandated by different criticalities, novel scheduling techniques are in need. In this paper, a mixed-criticality sporadic task model with multiple virtual deadlines is built and a certification-cognizant dynamic scheduling approach referred as earliest virtual-deadline first with mixed-criticality（EVDF-MC） is considered, which exploits different relative deadlines of tasks in different criticality modes. As for the corresponding schedulability analysis problem, a sufficient and efficient schedulability test is proposed on the basis of demand-bound functions derived in the mixed-criticality scenario. In addition, a modified simulated annealing（MSA）-based heuristic approach is established for virtual deadlines assignment. Experiments performing simulations with randomly generated tasks indicate that the proposed approach is computationally efficient and competes well against the existing approaches.

关键词： Avionics systems Mixed-criticality Real-time scheduling Schedulability analysis Simulated annealing

Periodic Variation in the Effect of Switching Frequency on the Harmonics of Power Electronic Converters

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Chinese Journal of Electrical Engineering 2020年第3期6卷 35-45页

作者： qiao li Jianan Chen Dong Jiang College of Electrical and Information Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Advanced Electromagnets Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074China

Switching frequency is an important factor in the performance control of power electronic *** can help optimize switching losses,switching ripples and electromagnetic interference,especially for newly developed high-switching-frequency silicon carbide *** variation in the switching-frequency methods has been developed for this purpose,especially the model-predictive variable switching-frequency pulse width modulation(VSFPWM)*** effect of periodic switching-frequency variation on the harmonics of a converter using double Fourier analysis and simulations are *** work verifies that the switching harmonics can be reduced by periodic variation in the switching frequency,and the low-frequency(baseband)harmonics only incur a slight *** analysis provides a theoretical foundation for the application of VSFPWM in power electronic converters.

关键词： Switching frequency PWM harmonics EMI

Preparation and Conducting Behavior of Amphibious Organic/Inorganic Hybrid Proton Exchange Membranes Based on Benzyltetrazole

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Chemical Research in Chinese Universities 2012年第2期28卷 345-352页

作者： qiao li-gen SHI Wen-fang CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026P.R.China

A series of novel amphibious organic/inorganic hybrid proton exchange membranes with H3PO4 doped which could be used under both wet and dry conditions was prepared through a sol-gel process based on acrylated triethoxysilane（A-TES） and benzyltetrazole-modified triethoxysilane（BT-TES）.The dual-curing approach including UV-curing and thermal curing was used to obtain the crosslinked *** glycol（400） diacrylate（PEGDA） was used as an oligomer to form the polymeric *** molecular structures of precursors were characterized by 1 H,13 C and 29 Si NMR *** thermogravimetric analysis（TGA） results show that the membranes exhibit acceptable thermal stability for their application at above 200 *** differential scanning calorimeter（DSC） determination indicates that the crosslinked membranes with the mass ratios of below 1.6 of BT-TES to A-TES and the same mass of H3PO4 doped as that of A-TES possess the-T g s,and the lowest T g（-28.9 ℃） exists for the membrane with double mass of H3PO4 doped as *** high proton conductivity in a range of 9.4―17.3 mS/cm with the corresponding water uptake of 19.1%―32.8% of the membranes was detected at 90 oC under wet ***,the proton conductivity in a dry environment for the membrane with a mass ratio of 2.4 of BT-TES to A-TES and double H3PO4 loading increases from 4.89×10-2 mS/cm at 30 ℃ to 25.7 mS/cm at 140 ℃.The excellent proton transport ability under both hydrous and anhydrous conditions demonstrates a potential application in the polymer electrolyte membrane fuel cells.

关键词： Amphibious Benzyltetrazole Organic/inorganic hybrid membrane Phosphorus acid Proton conductivity

Inertial Viscosity Iterative Method for Solving Pseudo-monotone Variational Inequality Problems and Fixed Point Problems

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Acta Mathematica Sinica,English Series 2022年第5期38卷 937-952页

作者： Gang CAI qiao li DONG Yu PENG School of Mathematics Science Chongqing Normal UniversityChongqing 401331P.R.China College of Science Civil Aviation University of ChinaTianjin 300300P.R.China

In this paper,we investigate a new inertial viscosity extragradient algorithm for solving variational inequality problems for pseudo-monotone and lipschitz continuous operator and fixed point problems for quasi-nonexpansive mappings in real Hilbert *** convergence theorems are obtained under some appropriate conditions on the ***,we give some numerical experiments to show the advantages of our proposed *** results obtained in this paper extend and improve some recent works in the literature.

关键词： Extragradient method variational inequality fixed point strong convergence quasi-nonexpansive mapping