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Relationship between the Stratospheric Arctic Vortex and Surface Air Temperature in the Midlatitudes of the Northern Hemisphere

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Journal of Meteorological Research 2024年第1期38卷 39-52页

作者： xue RAN Dingzhu hu Yang ZHANG Mei-Chen LIU Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044 School of Atmospheric Sciences Nanjing UniversityNanjing 210023

It is known that different relationships exist between the strength and displacement of the stratospheric polar vortex(SPV),and the surface air temperature(SAT)patterns in Eurasia and North America,but the mechanisms behind these relationships remain unclear,especially on an interannual *** on empirical orthogonal function(EOF)analysis using NCEP reanalysis data over 1958–2018,this study attempts to ascertain the relationship between the SPV intensity and displacement over the Arctic and the SATs in the midlatitudes of the Northern *** results indicate that a strengthened SPV corresponds to an SAT increase in Eurasia and a decrease in eastern North America and *** the SPV is shifted towards Eurasia,however,a corresponding SAT increase occurs in both North America and Eurasia,with a larger increase in North America than in ***,a strengthened SPV tends to correspond to a positive North Atlantic Oscillation-like circulation in the troposphere with negative geopotential height(GH)anomalies in Greenland and eastern North American continent and positive GH anomalies to the north of 45°N in Eurasia,which corresponds to lower SATs in North America than in ***,when the SPV shifted towards Eurasia,it was accompanied by a positive Pacific/North American-like pattern with a deepened Aleutian low,which corresponds to the increasing SATs in North *** tropospheric circulation changes are related to the response of tropospheric planetary wave activity to the SPV.A strengthened SPV corresponds to the weakening of tropospheric planetary wave-1 waves,which is accompanied by a negative GH in North America but a positive GH in *** the SPV shifted towards Eurasia,the tropospheric planetary wave-1(-2)waves strengthened(weakened),and the combined effects of the planetary wave-1 and wave-2 waves would cause positive GH anomalies in both Eurasia and North America.

关键词： stratospheric polar vortex surface air temperature teleconnection patterns planetary waves

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Hexagonal boron nitride based slippery liquid infused porous surface with anti-corrosion, anti-contaminant and anti-icing properties for protecting magnesium alloy

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Chinese Chemical Letters 2024年第4期35卷 532-538页

作者： Wenhao Yan Shuaiya xue xuerui Zhao Wei Zhang jian Li Key Laboratory of Eco-Functional Polymer Materials of the Ministry of Education College of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou 730070China

In an era where the concept of green development is deeply rooted, magnesium(Mg) alloy as a light metal has a long-term development prospect in the process of energy saving, emission reduction and environmental improvement. However, anti-corrosion performance of Mg alloy is poor due to the high chemical activity and low equilibrium potential, which limits the development of Mg alloy ***, three-dimensional mesopore hollow polypyrrole spheres(MHPS) were prepared, and the MHPS was inserted into the middle of the stacked hexagon boron nitride(h-BN) lamellae, which allowed the hBN to be separated forming a further composite with abundant pore structure. Subsequently, the MHPS/hBN-OH composite was uniformly sprayed on the Mg alloy surface via simple spraying method to form the superhydrophobic surface(SHS). Finally, the slippery liquid infused porous surface(SLIPS) was successfully fabricated by applying drops of silicone lubricant on the superhydrophobic coating surface. After a series of characterization and testing, the results showed that the stacking of h-BN lamellae was significantly reduced after h-BN was successfully embedded by MHPS. In addition, the fabricated SLIPS have excellent self-cleaning, mechanical stability, anti-icing and anti-corrosion properties. Therefore, the method of embedding polymer microspheres not only offers a new strategy for h-BN exfoliation, but also the successful prepared SLIPS largely retards the corrosion of Mg alloy while providing new ideas for the development of SLIPS.

关键词： Anti-corrosion Mg alloy Hexagon boron nitride Polypyrrole SLIPS

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Effect of nourishing Yin and purging fire Chinese herbal mixture on delaying light-induced premature puberty in rats

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Journal of Traditional Chinese Medicine 2024年第1期44卷 95-102页

作者： SUN Yanyan xue Yuanyuan SUN Wen WANG Yonghong YU jian Department of Traditional Chinese Medicine Children's Hospital of Fudan UniversityShanghai 201102China Department of Pediatrics Zibo Central HospitalZibo 255000China

OBJECTIVE:To elucidate the mechanism of the nourishing Yin and purging fire Chinese herbal mixture(NYPF)in delaying light-induced premature puberty in ***:Twenty-one days old female SpragueDawley rats were randomly assigned to normal group(N),long light exposure group(L),NYPF and normal saline group(NS).Rats in the L,NYPF and NS groups were exposed to 16 h:350 lux light/8 h:dark,while rats in the N group were exposed to 12 h:50 lux light/12 h:*** and normal saline was administered to the rats in the NYPF group or NS group,respectively,from day *** rats in every group were sacrificed at 9 *** day 28(P28),on the day when rat's vulva opened in the L group(L-VO),on the day when the first estrous interphase occurred in rats of L group(L-E1),and on the day when the second estrous interphase occurred in rats of L group(L-E2),***:On day 34,all rats in the L group,80%of rats in the NS group,40%of rats in the N group,and 20%of rats in the NYPF group showed complete opening of the *** P28,m RNA level of hypothalamic kisspeptin(Kiss-1)in the L group was significantly higher than that in the N group(P<0.05).The rats in the L and NS groups had significantly lower hypothalamic argininephenylalanine-amide(RFamide)-related peptide 3(RFRP-3)m RNA levels than those in the N group(P<0.05),whereas RFRP-3 m RNA level was significantly higher in the NYPF group than that in the L group(P<0.05).At L-VO,the ovarian index of the L and NS groups was significantly higher than that of the N group(P<0.05)and estradiol(E2)level of the NYPF group was significantly lower than that of the N and NS groups(P<0.05);hypothalamic Kiss-1 m RNA level in the L and NS groups was significantly higher than that in the N and NYPF groups(P<0.05),whereas hypothalamic RFRP-3 m RNA level in the L,NYPF,and NS groups was significantly lower than that in the N group(P<0.05).At L-E1,E2 level of the L and NS groups was significantly higher than that of the N group(P<0.01),wher

关键词： light puberty precocious kisspeptins RFRP-3 melatonin Nourishing Yin and Purging Fire

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Differences and Correlations of Morphological and Hemodynamic Parameters between Anterior Circulation Bifurcation and Side-wall Aneurysms

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Current Medical Science 2024年第2期44卷 391-398页

作者： Kai-kai GUO Chang-ya LIU Gao-hui LI jian-ping XIANG Xiao-chang LENG Yi-ke CAI xue-bin hu Department of Neurosurgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Department of Emergency Longhua HospitalShanghai University of Traditional Chinese MedicineShanghai 200032China Artery Flow Technology Co. Ltd.Hangzhou 310051China

Objective:The objective of this research was to explore the difference and correlation of the morphological and hemodynamic features between sidewall and bifurcation aneurysms in anterior circulation arteries,utilizing computational fluid dynamics as a tool for ***:In line with the designated inclusion criteria,this study covered 160 aneurysms identified in 131 patients who received treatment at Union Hospital of Tongji Medical College,huazhong University of Science and Technology,China,from January 2021 to September *** follow-up digital subtraction angiography(DSA)data,these cases were classified into two distinct groups:the sidewall aneurysm group and the bifurcation aneurysm *** and hemodynamic parameters in the immediate preoperative period were meticulously calculated and examined in both groups using a three-dimensional DSA reconstruction ***:No significant differences were found in the morphological or hemodynamic parameters of bifurcation aneurysms at varied locations within the anterior ***,pronounced differences were identified between sidewall and bifurcation aneurysms in terms of morphological parameters such as the diameter of the parent vessel(Dvessel),inflow angle(θF),and size ratio(SR),as well as the hemodynamic parameter of inflow concentration index(ICI)(P0.5,P<0.001).Conclusions:The significant differences in certain morphological and hemodynamic parameters between sidewall and bifurcation aneurysms emphasize the importance to contemplate variances in threshold values for these parameters when evaluating the risk of rupture in anterior circulation *** it is a bifurcation or sidewall aneurysm,these disparities should be *** morphological parameter SR has the potential to be a val

关键词： sidewall bifurcation unruptured aneurysms computational fluid dynamics

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Biomimetic soft robotic wrist with 3-DOF motion and stiffness tunability based on ring-reinforced pneumatic actuators and a particle jamming joint

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Science China(Technological Sciences) 2024年第3期67卷 774-790页

作者： hu TeTe LU Xinjiang YI jian WANG Yuhui XU Du State Key Laboratory of Precision Manufacturing for Extreme Service Performance School of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China

The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. However, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness;in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal *** this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist(BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator(SRBPA) with large axial, linear deformation(η_(lcmax)=70.6%,η_(lemax)=54.3%) and small radial expansion(η_(demax)=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint(PJJ) that combines particles with a membrane-covered ballsocket mechanism is developed to achieve various 3-DOF motions and high axial load-carrying capacity(>60 N). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible,stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability,and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 N and 36 N and torque of2.2 Nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demo

关键词： pneumatic soft actuators particle jamming robotic wrist soft robotics stiffness-tunable

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Experimental Study of Fuel-Air Mixing and Dilution Jets on Outlet Temperature Distribution in a Small Gas Turbine Combustor

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Journal of Thermal Science 2024年第5期33卷 1883-1896页

作者： CAI Wenzhe WU Jing hu Yingqi YANG Zhiqiang xue Xin LIN Yuzhen National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics Research Institute of Aero-EngineBeihang UniversityBeijing 100191China Beijing Institute of Power Machinery Beijing 100074China School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Experimental analysis was conducted to study the impact of fuel-air mixing and dilution jet on the temperature distribution in a small gas turbine combustor using various optical diagnostic *** strength and velocity of the swirler at the venturi exit were adjusted to modify the fuel-air mixture,which is presumed to dominate the heat release of the main combustion ***,the dilution hole configuration,including the number and size of the holes,was varied to investigate the dilution effect on outlet temperature *** optical diagnostic techniques,such as particle image velocimetry,planar Mie scattering,and OH~*chemiluminescence,were used to measure the flow field,fuel spray distribution,and flame structure,respectively.A reduction in swirling strength led to a decrease in the average flow rate in the throat,which improved the structure and symmetry of the axial vortex system in the sleeve,enhanced the mixing of fuel and gas in the dome swirling air,and ultimately,improved the temperature uniformity of the heat release *** to larger and sparse dilution jets,smaller and dense dilution jets tended to generate hot spots shifted towards the radial middle area.

关键词： small gas turbine combustor fuel-air mixing outlet temperature distribution dilution jet laser diagnostics

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Ramsey Numbers of Trees Versus Multiple Copies of Books

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 600-612页

作者： Xiao-bing GUO Si-nan hu Yue-jian PENG School of Mathematical Sciences Luoyang Normal UniversityLuoyang 471934China School of Mathematics Hunan UniversityChangsha 410082China

Given two graphs G and H,the Ramsey number R(G,H) is the minimum integer N such that any two-coloring of the edges of K_(N) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,H)≥(v(G)-1)(χ(H)-1)+s(H) if G is connected and v(G)≥s(H).A connected graph G is H-good if R(G,H)=(v(G)-1)(χ(H)-1)+s(H).Let tH denote the disjoint union of t copies of graph H,and let G∨H denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with n pages by B_(n),i.e.,the join K_(2) ∨■.Erd?s,Faudree,Rousseau and Schelp proved that T_(n) is B_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2B_(2).Our result implies that T_(n) is 2B_(2)-good if n≥5.

关键词： ramsey number ramsey goodness tree book

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Free Vibration of Stiffened Plate with Cracked Stiffeners

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Advances in Applied Mathematics and Mechanics 2024年第1期16卷 253-278页

作者： jian xue Lihua Chen Yue Sun Wei Zhang Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Department of Mechanics School of ScienceHarbin Institute of TechnologyShenzhenGuangdong 518055China Institute of Textiles and Clothing The Hong Kong Polytechnic UniversityHong KongChina

In this paper,a new cracked stiffener model for the stiffener with a partthrough and open crack is proposed,considering the compatibility condition of displacements between the plate and the *** on the first-order shear deformation theory,the free vibration of stiffened isotropic plates with cracked stiffeners are investigated for the first *** description of the crack parameters is based on the continuous equivalent bending stiffness and equivalent depth of the cracked beam,and it takes into consideration of shear deformation,bending-extensional coupling vibration,and eccentricity between the stiffeners and the *** stiffened plates with single or multiple cracked stiffeners are formulated and *** Ritz method with the modified characteristic functions is applied to demonstrate the effects of crack parameters(crack depth and location)coupling with the position and number of the cracked stiffeners on the vibration frequencies and modes of the stiffened *** validity and accuracy of the present solutions are verified through convergence studies and compared with the finite element results.

关键词： Free vibration stiffened plate cracked stiffener model crack Ritz method

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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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LaMnO_(3)/Co_(3)O_(4) nanocomposite for enhanced triethylamine sensing properties

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Journal of Rare Earths 2024年第4期42卷 733-742页

作者： jian Zhang Yanping Chen Ling Li xue Chen Wenya An Xiujuan Qian Yuye Tao School of Science Shandong Jianzhu UniversityJinan250100China

LaMnO_(3) modified Co_(3)O_(4) nanocomposites were prepared by simple hydrothermal method co mbined with sol-gel *** gas sensitivity properties of pure Co_(3)O_(4) and LaMnO_(3)/Co_(3)O_(4) with different composite proportions are *** is found that 0.6-LMO/Co_(3)O_(4) sensor has higher sensitivity to triethylamine(TEA)than pure Co_(3)O_(4) sensor,which is improved by 9.27 *** the working temperature is reduced from 150 to 130℃.Besides,it has excellent gas selectivity and *** improvement of the gas sensitivity of LaMnO_(3)/Co_(3)O_(4) sensor may be due to the fact that LaMnO_(3) is an effective catalyst,and the catalytic performance perhaps is beneficial to improving the sensing *** addition,the formation of p-p heterojunctions may be the key factor to improve the gas sensing *** work provides a new Co_(3)O_(4)-based gas sensing material for the detection of TEA.

关键词： Gas sensing Co_(3)O_(4) LaMnO_(3) Triethylamine Rareearths

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