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Bounding the sum of powers of the Laplacian eigenvaluesof graphs

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Applied Mathematics(A Journal of Chinese Universities) 2011年第2期26卷 142-150页

作者： chen xiao-dan QIAN Jian-guo School of Mathematical Sciences Xiamen University Xiamen 361005 Fujian P.R. China

For a non-zero real number α, let sα（G） denote the sum of the αth power of thenon-zero Laplacian eigenvalues of a graph G. In this paper, we establish a connection betweensα（G） and the first Zagreb index in which the H¨older’s inequality plays a key role. By usingthis result, we present a lot of bounds of sα（G） for a connected （molecular） graph G in terms ofits number of vertices （atoms） and edges （bonds）. We also present other two bounds for sα（G）in terms of connectivity and chromatic number respectively, which generalize those results ofZhou and Trinajsti′c for the Kirchho？ index [B Zhou, N Trinajsti′c. A note on Kirchho？ index,Chem. Phys. Lett., 2008, 455： 120-123].

关键词： Laplacian eigenvalues the first Zagreb index Kirchhoff index connectivity chromatic number.

机器人辅助步态训练结合重复经颅磁刺激对创伤性不完全性脊髓损伤患者下肢功能影响的综合分析

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颈腰痛杂志 2024年第4期45卷 678-682页

作者：曲新军茅丽丹陈晓丹海军青岛特勤疗养中心骨关节康复科山东青岛266000

目的探讨机器人辅助步态训练结合重复经颅磁刺激(rTMS)对创伤性不完全性脊髓损伤(ISCI)患者下肢功能的影响。方法选择2020年1月至2023年10月在该院就诊的腰椎创伤性ISCI患者46例作为研究对象,采用随机数字表法将患者分为对照组和观察组... 详细信息

目的探讨机器人辅助步态训练结合重复经颅磁刺激(rTMS)对创伤性不完全性脊髓损伤(ISCI)患者下肢功能的影响。方法选择2020年1月至2023年10月在该院就诊的腰椎创伤性ISCI患者46例作为研究对象,采用随机数字表法将患者分为对照组和观察组各23例。对照组采用机器人辅助步态训练,观察组在对照组的基础上给予rTMS治疗。观察并比较两组患者下肢运动评分(lower extremity functional scale,LEFS)、10 m步行测试、SCI-Ⅱ步行指数(WISCI-Ⅱ)、改良Ashworth量表(MAS)、步态测量的改善情况。结果治疗后,两组患者LEFS评分均较治疗前显著升高(P0.05)。治疗后,两组患者膝伸肌、髋内收肌、踝跖屈肌MAS与治疗前差异无统计学意义(P>0.05);治疗后两组患者上述指标差异无统计学意义(P>0.05)。治疗后,两组患者步速均较治疗前显著升高(P0.05);治疗前,两组患者步频、单支撑时间、双支撑时间、步长等差异均无统计学意义(P>0.05),且治疗后两组患者步频、单支撑时间、双支撑时间、步长等差异均无统计学意义(P>0.05)。结论rTMS可改善慢性创伤性ISCI患者的下肢运动功能,但对步态特征、支撑依赖程度和痉挛水平的影响不显著。

关键词：脊髓损伤步态训练机器人重复经颅磁刺激

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On the ordering of the Kirchhoff indices of the complements of trees and unicyclic graphs

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Applied Mathematics(A Journal of Chinese Universities) 2020年第3期35卷 308-320页

作者： chen xiao-dan HAO Guo-liang JIN De-quan College of Mathematics and Information Science Guangxi UniversityNanning 530004China Guangxi Center for Mathematical Research Guangxi UniversityNanning 530004China College of Science East China University of TechnologyNanchang 330013China

The Kirchhoff index Kf(G) of a graph G is defined to be the sum of the resistance distances between all pairs of vertices of G. In this paper, we develop a novel method for ordering the Kirchhoff indices of the complements of trees and unicyclic graphs. With this method, we determine the first five maximum values of Kf■ and the first four maximum values of Kf(ū),where ■ and ū are the complements of a tree T and unicyclic graph U, respectively.

关键词： Kirchhoff index tree unicyclic graph complement ordering

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课程思政在工科专业课程教学中的融合与探索

教育教学论坛 2024年第8期 157-160页

作者：陈晓丹张姝杨延嵩张雪芬北京联合大学智慧城市学院北京100101

课程思政是实现全员、全过程、全方位育人的重要环节,也是高校落实立德树人根本任务的战略举措。专业教师应充分发挥其主体作用,创新课程设计理念,在工科专业课程教学中将专业教学与思政元素紧密结合。阐述了课程思政的内涵,剖析了工科... 详细信息

课程思政是实现全员、全过程、全方位育人的重要环节,也是高校落实立德树人根本任务的战略举措。专业教师应充分发挥其主体作用,创新课程设计理念,在工科专业课程教学中将专业教学与思政元素紧密结合。阐述了课程思政的内涵,剖析了工科专业开展课程思政面临的困境与挑战,并基于“计算机网络”课程,给出了课程思政融入专业课教学的方法探究,包括重塑教学目标、完善教学内容、革新教学方法等,有效落实课程思政育人目标。

关键词：课程思政工科专业计算机网络

Recent progress in single crystal perovskite X-ray detectors

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Science China(Information Sciences) 2024年第3期67卷 5-19页

作者： xiao LIU Jun REN Yu-Ang chen Xiangshun GENG dan XIE Tian-Ling REN School of Integrated Circuits Tsinghua University Beijing National Research Center for Information Science and Technology (BNRist)

Perovskites have attracted extensive attention as radiation detection material due to their long carrier diffusion length and lifetime, high absorption coefficient, and flexible manufacturing process. Compared with polycrystalline structures, single crystal perovskites improve the performance of optoelectronic devices due to their low defect state density, better photoelectric characteristics, and chemical ***, we review the recent progress of single crystal perovskite X-ray detectors. First, we briefly introduced the basic concepts, detection mechanisms, figure of merits of perovskite X-ray detectors, and the preparation methods of single crystal perovskites. Then, we summarized the significant advancements in single crystal perovskite X-ray detectors in recent times. Finally, we discussed the critical challenges and some practicable solutions for developing high-performance X-ray detectors.

关键词： single crystal perovskites carrier transport radiation detection X-ray detectors X-ray imaging

In situ modification of heavy oil catalyzed by nanosized metal-organic framework at mild temperature and its mechanism

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Chinese Journal of Chemical Engineering 2024年第3期67卷 166-173页

作者： Li Wang Ji-Xiang Guo Rui-Ying Xiong chen-Hao Gao xiao-Jun Zhang dan Luo The Unconventional Oil and Gas Institute China University of Petroleum-BeijingBeijing 102200China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China

Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking and hydrogenation modification study of the dehydrated crude oil from the Shengli Oilfield. The optimal reaction conditions were determined through orthogonal experiments, and the components of the crude oil and modified oil samples were analyzed. The results revealed that the nanoMOF catalysts were successfully prepared and exhibited high catalytic activity. They could catalyze the cracking of large molecules in heavy oil at mild temperatures(<300°C), leading to the decomposition of the hydrogen donor. When the mass fraction of the catalyst was 0.2%, the mass fraction of the hydrogen donor was 1%, and the reaction temperature was 280°C, the Ni-MOF showed the best catalytic viscosity reduction effect. It could reduce the viscosity of heavy oil at 50°C from 15761.9 m Pa.s to 1266.2 m Pa.s,with a viscosity reduction rate of 91.97%. The modification effect of Co-MOF was the next best, which could reduce the viscosity of heavy oil to 2500.1 m Pa.s with a viscosity reduction rate of 84.14%. Molecular dynamics simulations revealed a strong interaction force between the MOF surface and asphaltene molecules. In the process of heavy-oil catalytic hydrogenation, the nano-MOF catalyst exhibited high catalytic activity. On the one hand, the empty d orbitals outside the metal atoms in the catalyst could polarize the carbon atoms in the organic matter, accelerating the breaking of long chains. On the other hand, the metal atoms in the catalyst could bond with the carbon σ bonds, breaking the carbon-carbon bonds. This disrupted the structure of the recombined components in the crude oil, irreversibly reducing the viscosity of the heavy oil and improving its fluidity.

关键词： Nano-sized MOF Petroleum Viscosity reduction Catalyst Nanomaterials

Local coordination and electronic interactions of Pd/MXene via dual‐atom codoping with superior durability for efficient electrocatalytic ethanol oxidation

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Carbon Energy 2024年第8期6卷 166-177页

作者： Zhangxin chen Fan Jing Minghui Luo xiaohui Wu Haichang Fu Shengwei xiao Binbin Yu dan chen Xianqiang Xiong Yanxian Jin School of Pharmaceutical and Chemical Engineering Taizhou UniversityTaizhouZhejiangChina School of Sciences Zhejiang Sci‐Tech UniversityHangzhouZhejiangChina

Catalyst design relies heavily on electronic metal‐support interactions,but the metal‐support interface with an uncontrollable electronic or coordination environment makes it ***,we outline a promising approach for the rational design of catalysts involving heteroatoms as anchors for Pd nanoparticles for ethanol oxidation reaction(EOR)*** doped B and N atoms from dimethylamine borane(DB)occupy the position of the Ti_(3)C_(2)lattice to anchor the supported Pd *** electrons transfer from the support to B atoms,and then to the metal Pd to form a stable electronic center.A strong electronic interaction can be produced and the d‐band center can be shifted down,driving Pd into the dominant metallic state and making Pd nanoparticles deposit uniformly on the ***‐obtained Pd/DB–Ti_(3)C_(2)exhibits superior durability to its counterpart(∼14.6%retention)with 91.1%retention after 2000 cycles,placing it among the top single metal anodic ***,in situ Raman and density functional theory computations confirm that Pd/DB–Ti_(3)C_(2)is capable of dehydrogenating ethanol at low reaction energies.

关键词： durability electronic interactions ethanol oxidation heteroatom codoping Pd/MXene

The First Five Years of a Phase Theory for Complex Systems and Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1728-1743页

作者： dan Wang Wei chen Li Qiu Division of Decision and Control Systems KTH Royal Institute of TechnologyStockholm 10044Sweden Department of Mechanics and Engineering Science&the State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing 100871China Hong Kong University of Science and Technology Hong KongChinaand also with the Southern University of Science and TechnologyShenzhen 518055China

In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase *** the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.

关键词： Consensus and synchronization matrix phases multi-agent systems phase theory sectored real lemma small phase theorem.

Odorant receptor orthologues from moths display conserved responses to cis-jasmone

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Insect Science 2024年第4期31卷 1107-1120页

作者： xiao-Qing Hou Zhongqiang Jia dan-dan Zhang Guirong Wang Shenzhen Branch Guangdong Laboratory for Lingnan Modern AgricultureSynthetic Biology Laboratory of the Ministry of Agriculture and Rural AffairsAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenGuangdong ProvinceChina State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina Department of Biology Lund UniversityLundSweden

In insects,the odorant receptor(OR)multigene family evolves by the birth-and-death evolutionary model,according to which the OR repertoire of each species has undergone specific gene gains and losses depending on their chemical environment,resulting in taxon-specific OR lineage radiations with different sizes in the phylogenetic *** the general divergence in the gene family across different insect orders,the ORs in moths seem to be genetically conserved across species,clustered into 23 major clades containing multiple orthologous groups with single-copy gene from each *** hypothesized that ORs in these orthologous groups are tuned to ecologically important compounds and functionally ***-Jasmone is one of the compounds that not only primes the plant defense of neighboring receiver plants,but also functions as a behavior regulator to various *** test our hypothesis,using Xenopus oocyte recordings,we functionally assayed the orthologues of BmorOR56,which has been characterized as a specific receptor for *** results showed highly conserved response specificity of the BmorOR56 orthologues,with all receptors within this group exclusively responding to *** is supported by the dN/dS analysis,showing that strong purifying selection is acting on this ***,molecular docking showed that the ligand binding pockets of BmorOR56 orthologues to cis-jasmone are *** together,our results suggest the high conservation of OR for ecologically important compounds across Heterocera.

关键词： cis-jasmone evolutionary conservation functional characterization molec-ular docking moths purifying selection