检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

Recent Advances in Asymmetric Structural Composites for Excellent Electromagnetic Interference Shielding: A Review

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第6期42卷 693-710页

作者： Ying Zhou Bai xue Lan Xie Chang-mei Wu Qiang Zheng Department of Polymer Materials and Engineering College of Materials and Metallurgy Guizhou University National Engineering Research Center for Compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane Processes State Key Laboratory of Public Big Data Guizhou University Department of Polymer Science and Engineering Zhejiang University

Since electromagnetic pollution is detrimental to human health and the environment, numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE) via designing the hierarchical structures for electromagnetic interference(EMI) shielding polymer composites. Among the plentiful structures, the asymmetric structures are currently a hot spot, principally categorizing into multi-layered, porous, fibrous, and segregated asymmetric structures, which endows the high EMI shielding performance for polymer composites incorporated with magnetic, conductive, and/or dielectric micro/nano-fillers, due to the “absorption-reflection-reabsorption” shielding mechanism. Therefore, this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties, which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G) technology.

关键词： Asymmetric structure Microano functional filler Polymer composite Electromagnetic interference shielding

Inherently Chiral and Symmetrical Heteroatom-Doped Zigzag-Type Hydrocarbon Belts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第5期6卷 1198-1210页

作者： xue-Yuan wang Xin-Yu Zhang Shuo Tong Qing-Hui Guo mei-Ling Tan Cheng-Jun Li mei-Xiang wang Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084

hydrocarbon belts due to their potential applications in carbon *** contrast,heteroatomembedded zigzag hydrocarbon belts as advanced design strategies with fascinating structures and desirable,unique properties have remained largely unexplored,and inherently chiral ones are ***,we report the synthesis of a diversity of symmetric and highly enantiopure inherently chiral O-and N-doped zigzag-type hydrocarbon belts starting from strainless macrocycles based on fjord-stitching *** readily available pertriflated resorcin[6]arene underwent partial hydrolyses and intramolecular S_(N)Ar reactions to form a calix[3](9H-xanthene)derivative and a prochiral half-belt *** transformations of calix[3](9H-xanthene)into C_(3v)-symmetric molecular belts were achieved by closing the rest of the fjords with triple intramolecular S_(N)Ar reactions and Yamamoto homo coupling reactions,as well as palladiumcatalyzed intermolecular acridination reactions with primary *** prochiral half-belt underwent enantioselective desymmetrizative mono-acridination to afford an inherently chiral N,O_(4)-bridged pseudo-belt with an enantiomeric excess(ee)value of>99%under the catalysis of Pd(OAc)_(2)and(R)-*** closure reactions of the pseudo-belt produced diverse heteroatom-inlayed zigzag-type hydrocarbon belts of inherent ***,we showed the unique cavity structures of the belts and demonstrated interesting chiroptic properties of the inherently enantiopure chiral *** research opens the door for the exploration of novel and sophisticated symmetric and inherently chiral molecular nanobelt structures with outstanding physical and chemical properties,as well as potential applications.

关键词： zigzag-type molecular belt heterocycle chiroptical property fjord-stitching strategy resorcinarene

Study on the Effect of Ginaton on Reducing Cerebral Vasospasm and Early Brain Injury after Hemorrhagic Stroke by Inhibiting Inflammatory Response

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Traditional Chinese Medicine 2024年第1期10卷 33-39页

作者： xue-Bo Pang Xiao-Lin Zhang mei-Rong wang Ying Yuan Xiao Zhang Department of Neurology Xingtai Third HospitalXingtaiChina

Objective:The objective of this study was to investigate the effects and possible mechanisms of action of ginseng on cerebral vasospasm and early brain injury(EBI)following hemorrhagic *** and Methods:Sprague-Dawley(SD)rats(n=48)were randomly divided into sham operation(sham group),subarachnoid hemorrhage(SAH)model(SAH group),normal saline(NS group),and Ginaton(Extract of Ginkgo Biloba Leaves Drops)intervention(gin group)***-1 m RNA and tumor necrosis factor levels were detected using reverse transcription-polymerase chain *** relative expression of m RNA was detected by Western ***:(1)Compared with the sham group,the SAH,NS,and gin groups had different degrees of neurological *** with the SAH and NS groups,the neurological deficits in the gin group were significantly improved(P<0.05).(2)Compared with the sham group,the relative expression levels of MCP-1 m RNA in the SAH,NS,and gin groups were 5.1±0.9,3.4±0.6,and 2.5±0.4,respectively;the relative expression levels of m RNA were 13.3±2.4,11.2±1.8,and 3.8±0.6,respectively.(3)The apoptosis rates of brain tissue in the sham,SAH,NS,and gin groups were 4.8±0.7,54.2±10.3,50.1±7.4,and 28.4±4.5,respectively.(4)Western blot showed that the relative expression levels of toll-like receptor-4(TLR-4)protein in the sham,SAH,NS,and gin groups were 0.29±0.03,0.87±0.15,0.65±0.13,and 0.41±0.17,respectively;the relative expression levels of B protein were 0.21±0.04,0.96±0.14,0.73±0.18,and 0.30±0.05,*** treatment could inhibit TLR-4 and nuclear factor-κB(NF-κB)protein ***:Dona tablets may inhibit activation of the NF-κB signaling pathway,and SAH-induced inflammatory response,so as to reduce cerebral vasospasm and EBI.

关键词： Cerebral hemorrhage early brain injury ginaton neurological deficit nuclear factor-κB

Energy transfer, anticounterfeiting, white light emission and sensing in fine-regulating series of lanthanide metal-organic frameworks

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第3期42卷 446-454,I0001页

作者： Juanjuan xue Yao wang Guoping Yang Yaoyu wang Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education Shaanxi Key Laboratory of Physico-Inorganic ChemistryCollege of Chemistry&Materials ScienceNorthwest UniversityXi'an710127China

Three lanthanide ions and a rigid(1,1'-biphenyl)-2,4,6-tricarboxylic acid(H_(3)bptc) ligand led to the isostructural lanthanide metal-organic frameworks(Ln-MOFs) {[Ln(bptc)(H_(2)O)_(3)]·3H_(2)O}_n(Lnbptc, Ln = Eu,Tb, Gd, Eu_(x)Tb_(1—x), Eu_(x)Gd_(1-x), Tb_(x)Gd_(1-x), and Eu_(0.12)Tb_(0.52)Gd_(0.36)). The density functional theory(DFT) and time-dependent DFT calculation were expanded on H_3bptc, which point to the occurrence of “antenna effect”. The minor diameter samples of Eubptc, Tbbptc, and Gdbptc can also be attained via the microwave synthesis and employed for handwriting anticounterfeiting. Interestingly, the typical red emission of Eu^(3+) and green emission of Tb~(3+) could be fine-tuned by Gd^(3+) via chemical mixing to be full-color emissions bimetallic doped Eu_(x)Tb_(1-x)bptc, Eu_(x)Gd_(1-x)bptc, and Tb_(x)Gd_(1-x)bptc. The above synthetic bimetallic MOFs can be fixed in positioning boxes of quick response(QR) codes with diverse emission for anticounterfeiting. The message can be decoded under the irradiation of 365 nm ultraviolet lamp while invisible in the daylight. Notably, the trimetallic doped Eu_(0.12)Tb_(0.52)Gd_(0.36)bptc emits white light with the CIE color coordinate(0.34, 0.34). Furthermore, Tbbptc is demonstrated to be a sensitive probe toward nitrobenzene and acetone with multiple mechanisms.

关键词： Metal-organic frameworks Anticounterfeiting White light-emitting Sensing Rare earths

Trends in Fruit and Vegetable Intake Among the Labor Force Population—China,2010-2018

在线全文

学校读者我要写书评

暂无评论

China CDC weekly 2024年第18期6卷 401-407,I0008页

作者： Lan wang mei Zhang Xiao Zhang Zhenping Zhao Chun Li Mengting Yu Taotao xue Feng Tan Limin wang Division of Chronic Disease and Risk Factor Surveillance National Center for Chronic and Non-communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina Chinese Center for Disease Control and Prevention BeijingChina

Introduction:This research investigates trends pertaining to the prevalence of low fruit and vegetable consumption among the labor force population in *** study considered data derived from four nationally representative cross-sectional ***:The data under review for this study was derived from the China Chronic Disease and Risk Factor Surveillance(CCDRFS)carried out in 2010,2013,2015,and 2018,*** utilized a food frequency questionnaire to evaluate the quantity and frequency of fruit and vegetable *** estimated prevalence of low fruit and vegetable consumption was calculated for each survey,while considering factors such as sex,age,location,and socioeconomic status(SES).Participants’SES was ascertained via latent class analysis,serving to identify distinct classes based on criteria such as education,occupation,and household income per *** regression was deployed to determine the statistical significance of ***:From 2010 to 2018,there was a notable increase in the average daily consumption of vegetables and fruits among the working population,rising from 418.6 g/day to 491.8 g/day(P0.05 for trend).Conclusion:Over the past nine years,there has been a notable decline in the prevalence of low fruit and vegetable consumption among the labor force population in ***,the comparatively deficient intake of fruits and vegetables evident among individuals of lower SES warrants further attention.

关键词： intake occupation utilized

Design,preparation,microstructure and mechanical property of the lightweight radiation-shielding Mg-Ta-Al composites basing differential temperature hot rolling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第6期12卷 2433-2446页

作者： Wenbo Luo Songya Feng Xiuzhu Han Li Zhou Qinke Kong Zhiyong xue Jianzhao wang mei Zhan Xianhua Chen Fusheng Pan Institute for Advanced Materials North China Electric Power UniversityBeijing 102206China Beijing Institute of Spacecraft System Engineering Beijing 100094China Sinosteel Equipment&Engineering Co Ltd.Beijing100080China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Inner Mongolia 014030China School of Materials Science Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China

A novel lightweight,radiation-shielding Mg-Ta-Al layered metal-matrix composite(LMC)was successful designed by doping the extremely refractory metal(Ta)into Mg *** Mg-based LMCs sheets shows excellent radiation-dose shield effect,about 145 krad·a^(−1),which is about 17 times of traditional Mg alloy,while its surface density is only about 0.9 g·cm^(−2),reducing by 60%than that of pure *** quantitate relationship between radiation-dose and the materials’thickness was also confirmed to the logistic function when the surface density is in the range of 0.6-1.5 g·cm^(−2).Meantime,the rolling parameters,interface microstructure and mechanical properties in both as-rolled and annealing treated samples were *** sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface,as well as a thin Al film with a thickness of about 10μ*** special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al *** interface bonding strength reaches up to 54-76 *** ultimate tensile strength(UTS)and yield strength(TYS)of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa,respectively,along with an elongation of 5.8%.The molecular dynamics(MD)analysis results show that the two interfaces exhibit different formation mechanism,the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement,while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

关键词： Dissimilar metals composites Mg based alloys Radiation shielding Hot rolling Lightweight

Characterizations of semihoops based on derivations

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 291-310页

作者： wang mei ZHANG Xiao-hong School of Electrical and Control Engineering Shaanxi University of Science and TechnologyXi'an 710021China School of Arts and Sciences Shaanxi University of Science and TechnologyXi'an 710021China School of Mathematics and Statistics Weinan Normal UniversityWeinan 714099China

In this paper,we discuss the related properties of some particular derivations in semihoops and give some characterizations of ***,we prove that every Heyting algebra is isomorphic to the algebra of all multiplicative derivations and show that every Boolean algebra is isomorphic to the algebra of all implicative ***,we show that the sets of multiplicative and implicative derivations on bounded regular idempotent semihoops are in oneto-one correspondence.

关键词： (prelinear)semihoop derivation Heyting algebra Galois connection

The Boundary Element Method for Ordinary State-Based Peridynamics

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2807-2834页

作者： xue Liang Linjuan wang State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceCollege of EngineeringPeking UniversityBeijing100871China CAPT-HEDPS and IFSA Collaborative Innovation Center of MoECollege of EngineeringPeking UniversityBeijing100871China School of Astronautics Beihang UniversityBeijing100191China

The peridynamics(PD),as a promising nonlocal continuum mechanics theory,shines in solving discontinuous *** to now,various numerical methods,such as the peridynamic mesh-free particlemethod(PD-MPM),peridynamic finite element method(PD-FEM),and peridynamic boundary element method(PD-BEM),have been ***-BEM,in particular,outperforms other methods by eliminating spurious boundary softening,efficiently handling infinite problems,and ensuring high computational ***,the existing PD-BEM is constructed exclusively for bond-based peridynamics(BBPD)with fixed Poisson’s ratio,limiting its applicability to crack propagation problems and scenarios involving infinite or semi-infinite *** this paper,we address these limitations by introducing the boundary element method(BEM)for ordinary state-based peridynamics(OSPD-BEM).Additionally,we present a crack propagationmodel embeddedwithin the framework ofOSPD-BEM to simulate crack *** validate the effectiveness of OSPD-BEM,we conduct four numerical examples:deformation under uniaxial loading,crack initiation in a double-notched specimen,wedge-splitting test,and threepoint bending *** results demonstrate the accuracy and efficiency of OSPD-BEM,highlighting its capability to successfully eliminate spurious boundary softening phenomena under varying Poisson’s ***,OSPDBEMsignificantly reduces computational time and exhibits greater consistencywith experimental results compared to PD-MPM.

关键词： Ordinary state-based peridynamics boundary element method crack propagation fracture toughness