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Friction 2024年第7期12卷 1564-1579页

作者： Linlin duan Dan JIA Jian LI Jianfang LIU Haitao duan State Key Laboratory of Special Surface Protection Materials and Application Technology Wuhan Research Institute of Materials ProtectionWuhan 430030China Hubei Longzhong Laboratory Xiangyang 441000China College of Life Science and Technology Wuhan Polytechnic UniversityWuhan 430030China

In this work,the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid–liquid nanosized contact interface is taken,and the superior friction-reducing property of Cu_(3)(PO_(4))2·3H_(2)O(CuP)oil-based additives has been confirmed for titanium ***-dimensional(3D)CuP nanoflowers(CuP-Fs)with a strong capillary absorption effect are prepared to achieve the homogeneous mixing of solid CuP and lubricating *** by CuP-Fs additives for titanium alloy,friction coefficient(COF)can be reduced by 73.68%,and wear rate(WR)reduced by 99.69%.It is demonstrated that the extraordinary friction-reducing property is due to the repulsive solid–liquid interface with low viscous shear force originating from Coulomb repulsion between polar water molecules in CuP and non-polar oil ***,any steric hindrance or connection between this repulsive solid–liquid interface will trigger the adhesion and increase the viscous shear force,for example,dispersant,hydrogen bondings,and shaky adsorbed water ***,the lamellar thickness of CuP and the molecular size of lubricant both have a great influence on tribological *** the lubrication mechanism based on interface Coulomb repulsion is proposed that may help broaden the scope of the exploration in low-friction nanomaterial design and new lubricant systems.

关键词： lubrication nanomaterial additive solid-liquid interface wear

Triangle-free Graphs with Three Positive Eigenvalues

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Algebra Colloquium 2024年第3期31卷 525-540页

作者： Fang duan School of Mathematical Sciences Xinjiang Normal UniversityUrumqi 830017China

A graph G is called triangle-free if G does not contain any triangle as its induced *** G_(n)be the set of triangle-free graphs of order n each of which has three positive *** this paper,we find 20 specific graphs in G_(n),each of which has nullity no more than 2,and we show that in terms of three graph transformations all the other graphs of G_(n)can be constructed from these 20 specific ***,we completely characterize the triangle-free graphs with exactly three positive eigenvalues.

关键词： positive(negative)inertia index nullity triangle-free graph

A comprehensive research on wear resistance of GH4169 superalloy in longitudinal-torsional ultrasonic vibration side milling with tool wear and surface quality

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Chinese Journal of Aeronautics 2024年第4期37卷 556-573页

作者： Baoqi CHANG Zhaoxi YI Fen ZHANG Lian duan Ji-an duan School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of High Performance and Complex Manufacturing Central South UniversityChangsha 410083China School of Physics and Electronics Central South UniversityChangsha 410083China

To improve the service and machining performance of the workpiece, the tool wear mechanisms, surface machining quality, and wear resistance in conventional side milling(CSM)and longitudinal-torsional ultrasonic vibration side milling(LTUVSM) of GH4169 superalloy at different cutting lengths are investigated systematically. Tool wear mechanisms are revealed and the correlation between machined surface quality with tool wear is analyzed correspondingly. Tool wear patterns mainly include adhesive wear, diffusion wear, abrasive wear, and chipping *** surface quality is achieved in LTUVSM due to a maximum reduction of flank wear bandwidth and wear rate by 71.9% and 71.5%, respectively, compared to CSM. The friction coefficient,initial wear stage time, and wear volume of dry sliding wear were measured to evaluate the workpiece wear resistance. The maximum reductions in friction coefficient and wear volume in LTUVSM are 18.2% and 15.8% compared to CSM. The regular ultrasonic vibration textures suppress the friction and the growth of contact nodes in the contact area, decreasing the degree of surface wear, which is demonstrated by a 38.8% increase in initial wear stage time compared to *** conclusion, the workpiece in LTUVSM exhibits higher wear resistance because of the improvement of tool wear and the guarantee of surface quality.

关键词： Dry sliding wear Surface quality Tool wear Ultrasonic vibration Wear resistance

Two-dimensional ballistic transistors for advanced-node integrated circuits

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National Science Review 2024年第3期11卷 9-10页

作者： Jia Li Xidong duan Hunan Provincial Key Laboratory of Two-Dimensional Materials State Key Laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University

As the feature size of metal-oxide-semiconductor-field-effect-transistors(MOSFETs) in integrated circuits(ICs)is reduced to sub-10-nm, the traditional channel materials are plagued by enhanced scattering and short-cha... 详细信息

关键词： CONTACT

Extremum seeking control for UAV close formation flight via improved pigeon-inspired optimization

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Science China(Technological Sciences) 2024年第2期67卷 435-448页

作者： YUAN GuangSong duan HaiBin State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang University(BUAA)Beijing 100083China

This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation *** proposed design scheme combines a Newton-Raphson method with an extended Kalman filter(EKF)to dynamically estimate the optimal position of the following UAV relative to the leading *** reflect the wake vortex effects reliably,the drag coefficient induced by the wake vortex is considered as a performance ***,the performance function is parameterized by the first-order and second-order terms of its Taylor series *** the excellent performance of nonlinear estimation,the EKF is used to estimate the gradient and the Hessian matrix of the parameterized performance *** output feedback of the proposed scheme is determined by iterative calculation of the Newton-Raphson *** with the traditional ESC and the classic ESC,the proposed design scheme avoids the slow continuous time integration of the *** allows a faster convergence of relative position ***,the proposed method can provide a smoother command during the seeking process as the second-order term of the performance function is taken into *** convergence analysis of the proposed design scheme is accomplished by showing that the output feedback is a supermartingale *** improve estimation performance of the EKF,a improved pigeon-inspired optimization(IPIO)is proposed to automatically tune the noise covariance *** Carlo simulations for a three-UAV close formation show that the proposed design scheme is robust to the initial position of the following UAV.

关键词： unmanned aerial vehicle close formation extremum seeking control Newton-Raphson method improved pigeon-inspired optimization

Investigation of the cell composition and gene expression in the delayed-type hypersensitivity tuberculin skin test

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Military Medical Research 2024年第1期11卷 148-151页

作者： Hui-Juan duan Hong-Qian Chu ting-Ming Cao Guang-Ming Dai Na Tian Gang Sheng Zhao-Gang Sun Beijing Key Laboratory in Drug Resistant Tuberculosis Research Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijing Chest HospitalCapital Medical UniversityBeijing 101149China

Dear Editor,The tuberculin skin test(TST)reagents have continuously improved,with the ESAT6-CFP10(EC)test having recently been introduced,but are seldom based on the direction of the delayed-type hypersensitivity(DTH)*** studies only partially showed the infiltration and activation of immune cells and the production of cytokines of the skin induration[1,2],and lack the detailed measurements of cell proportions and gene expression in the DTH ***,in this study,we revealed the comprehensive characteristics of DTH by single-cell RNA sequencing(scRNA-seq)in the guinea pig tuberculosis(TB)model[Experimental Animal Welfare Ethics Committee,Beijing Tuberculosis and Thoracic Tumor Research Institute(2021-064)].

关键词： Tuberculin skin test Delayed-type hypersensitivity Single-cell RNA sequencing

Landscape ecological risk assessment and its driving factors in the Weihe River basin,China

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Journal of Arid Land 2024年第5期16卷 603-614页

作者： CHANG Sen WEI Yaqi DAI Zhenzhong XU wen WANG Xing duan Jiajia ZOU Liang ZHAO Guorong REN Xiaoying FENG Yongzhong College of Agronomy Northwest A&F UniversityYangling 712100China

Weihe River basin is of great significance to analyze the changes of land use pattern and landscape ecological risk and to improve the ecological basis of regional *** on land use data of the Weihe River basin in 2000,2010,and 2020,with the support of Aeronautical Reconnaissance Coverage Geographic Information System(ArcGIS),GeoDa,and other technologies,this study analyzed the spatial-temporal characteristics and driving factors of land use pattern and landscape ecological *** showed that land use structure of the Weihe River basin has changed significantly,with the decrease of cropland and the increase of forest land and construction *** the past 20 a,cropland has decreased by 7347.70 km2,and cropland was mainly converted into forest land,grassland,and construction *** fragmentation and dispersion of ecological landscape pattern in the Weihe River basin were improved,and land use pattern became more ***,landscape ecological risk of the Weihe River basin has been *** landscape ecological risk area decreased by 19,177.87 km2,high landscape ecological risk area decreased by 3904.35 km2,and moderate and low landscape ecological risk areas continued to *** is worth noting that landscape ecological risks in the upper reaches of the Weihe River basin are still relatively serious,especially in the contiguous areas of high ecological risk,such as Tianshui,Pingliang,Dingxi areas and some areas of Ningxia Hui Autonomous *** ecological risk showed obvious spatial dependence,and high ecological risk area was *** the driving factors,population density,precipitation,normalized difference vegetation index(NDVI),and their interactions are the most important factors affecting the landscape ecological risk of the Weihe River *** findings significantly contribute to our understanding of the ecological dynamics in the Weihe River basin,providing crucial insights for sustainable mana

关键词： land use ecological risk spatiotemporal distribution geographic detector driving factors

Differences between two methods to derive a nonlinear Schrödinger equation and their application scopes

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Chinese Physics B 2024年第2期33卷 421-429页

作者：陈羽西张恒段文山 College of Physics and Electronic Engineering Northwest Normal UniversityLanzhou 730070China

The present paper chooses a dusty plasma as an example to numerically and analytically study the differences between two different methods of obtaining nonlinear Schrödinger equation(NLSE).The first method is to derive a Korteweg–de Vries(KdV)-type equation and then derive the NLSE from the KdV-type equation,while the second one is to directly derive the NLSE from the original *** is found that the envelope waves from the two methods have different dispersion relations,different group *** results indicate that two envelope wave solutions from two different methods are completely *** results also show that the application scope of the envelope wave obtained from the second method is wider than that of the first one,though both methods are valuable in the range of their corresponding application *** is suggested that,for other systems,both methods to derive NLSE may be correct,but their nonlinear wave solutions are different and their application scopes are also different.

关键词： dusty plasmas nonlinear waves particle-in-cell simulation

Wedelolactone attenuates sepsis-associated acute liver injury by regulating the macrophage M1/M2 polarization balance through the PI3K/AKT/NF-κB signalling pathway

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Traditional Medicine Research 2024年第11期9卷 1-11页

作者： Wang-ting Li Jin-Yi Chen Shao-Jie Huang Dong-Mei Hu Xing-Ru Tao Fei Mu Jing-Yi Zhao Chao Guo Jia-Lin duan Jing-wen Wang Department of Pharmacology Shaanxi University of Chinese MedicineXianyang 712046China Department of Pharmacy Xijing HospitalFourth Military Medical UniversityXi’an 710032China Institute of Medical Research Northwestern Polytechnical UniversityXi’an 710032China.

Background:Liver injury caused by sepsis seriously impairs the normal physiology of the ***(WED)has an obvious anti-inflammatory effect against liver damage caused by various ***,further research is needed to determine if WED might mitigate acute liver damage linked to sepsis by influencing macrophage ***:We first assessed the effect of WED on lipopolysaccharides-triggered liver injury by biochemistry assay and tissue *** factors were assessed using the ELISA *** expression of Cluster of Differentiation 86(CD86)and Cluster of Differentiation 206(CD206)was measured by immunofluorescence *** protein levels of inducible nitric oxide sythase(iNOS),Arginase 1(Arg-1),phosphatidylinositol 3-kinase(PI3K),protein kinase B(AKT),PI3K phosphorylation(p-PI3K),AKT phosphorylation(p-AKT),inhibitor of kappa B kinase(IKK),inhibitor of kappa B(IκB),and nuclear factor kappa-B(NF-κB)p65 were quantified by western blot ***:WED decreased the level of alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP)and malondialdehyde,and increased the activity of superoxide dismutase(SOD)and glutathione peroxidase(GSH-PX).Moreover,WED exerted effective anti-inflammatory effects by decreasing the level of Tumor necrosis factor-α(TNF-α)and Interleukin 6(IL-6)and increasing the level of Interleukin 10(IL-10)in serum and *** not only decreased CD86 and iNOS expression but also increased CD206 and Arg-1 *** also downregulated the increased expression of PI3K,AKT,p-PI3K,p-AKT,IKK,and NF-κB p65 induced by lipopolysaccharides,while up-regulated the decreased expression of Iκ***,LY294002 with WED decreased the expression of protein PI3K,AKT,p-PI3K,p-AKT,IKK and NF-κB p65,and raised the expression of IκBα.Conclusion:Wedelolactone could attenuate sepsis-associated acute liver injury,and its mechanism may be associated with balancing pro-inflammatory and anti-inflamm

关键词： Wedelactone sepsis liver injury macrophage polarization PI3K/AKT/NF-κB

Drogue detection for autonomous aerial refueling via hybrid pigeon-inspired optimized color opponent and saliency aggregation

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Chinese Journal of Aeronautics 2024年第5期37卷 27-38页

作者： Tongyan WU Haibin duan Yanming FAN State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083China Virtual Reality Fundamental Research Laboratory Department of Mathematics and TheoriesPeng Cheng LaboratoryShenzhen 518000China AVIC Shenyang Aircraft Design and Research Institute Shenyang 110035China

Drogue detection is one of the challenging tasks in autonomous aerial refueling due to the requirement for accuracy and *** detection based on image intrinsic cues can achieve fast detection,but with poor *** studies reveal that optimization-based methods provide accurate and quick solutions for saliency *** paper presents a hybrid pigeon-inspired optimization method,the optimized color opponent,that aims to adjust the weight of color opponent channels to detect the drogue *** can optimize the weights in the selected aerial refueling scene offline,and the results are applied for drogue detection in the scene.A novel algorithm aggregated by the optimized color opponent and robust background detection is presented to provide better precision and *** results on benchmark datasets and aerial refueling images show that the proposed method successfully extracts the saliency region or drogue and exhibits superior performance against the other saliency detection methods with intrinsic *** algorithm designed in this paper is competent for the drogue detection task of autonomous aerial refueling.

关键词： Autonomous aerial refueling Drones Hybrid pigeon-inspired optimization Color opponent Saliency detection Saliency aggregation