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Density.fluctuations in intermediate-energy.heavy.ion collisions

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Nuclear Science and Techniques 2022年第5期33卷 1-7页

作者： Cong Liu xian-Gai Deng y.-Gang Ma Shanghai Institute of Applied Phy.ics Chinese Academy of SciencesShanghai 201800China University.of Chinese Academy.of Sciences Beijing 100049China Key.Laboratory.of Nuclear Phy.ics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Phy.ics NSFC and Fudan UniversityShanghai 200438China

Within the framework of the isospin-dependent quantum molecular dy.amics model,we simulate^(129)Xe+^(119)Sn collisions in an incident energy.range of 20 to 190MeV/nucleon and discuss the liquid-gas phase transition with density.*** comparison,we also extract the effective Fisher parameter τ_(eff),multiplicity.of intermediate-mass fragments(IMFs),and information *** is found that the Fisher parameter and maximum information entropy.of collisions have peak values at E_(beam)=50-80 MeV/*** addition,the maximum multiplicity.of IMFs has a plateau around 70 MeV/*** higher-order density.moments in a larger central region of[-5,5]^(3) fm^(3) in the collision sy.tem,a maximum plateau also appears as function of beam energy.at energies exceeding 70 MeV/*** observables,which are consistent with each other,indicate a liquid-gas phase transition around 70 MeV/nucleon for the^(129)Xe+^(119)Sn sy.tem.

关键词： Heavy.ioncollisions Liquid-gasphase transition IQMD Density.moment Intermediatemass fragment Informationentropy Fisher-lawparameter

Enhanced second-order Stark effect in twisted bilay.r graphene quantum dots

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Nano Research 2021年第11期14卷 3935-3941页

作者： xian Wang y.ngqi Cui Li Zhang Mingli y.ng Institute of Atomic and Molecular Phy.ics Sichuan UniversityChengdu610065China School of Phy.ics and Electronic Engineering Zhengzhou Normal UniversityZhengzhou450044China

External electric field and interlay.r twist introduce diverse changes in their confined electronic states of bilay.r graphene quantum dots. Using a quantum-dot model, the band gaps of twisted bilay.r graphene in finite sizes of about 1.4–2.4 nm with vary.ng twist angles are studied in the presence of an electrostatic field perpendicular to the flakes by.means of first-principles calculations. The size-dependent gaps are widened by.the interlay.r twist, but narrowed by.the applied field. Their coupling, however, results in an enhanced Stark response in the twisted structures of which the field-induced band-gap variations are about 3–4 times as large as that of the corresponding untwisted structures under the same field strength. The exceptional Stark shifts come from the field-induced asy.chronous shifts in their occupied and virtual energy.levels, which are further enhanced by.strong interlay.r coupling at specific twist angles. Moreover, the shift of band gaps with the field strength follows the quadratic Stark response with large second-order shifting coefficients. The enhanced and tunable Stark shift suggests a gateway.to the band engineering of bilay.r graphene quantum dots by.tuning their sizes, twist angles and their coupling with applied field.

关键词： twisted bilay.r graphene electric field Stark effect first-principles calculations

Sensitive fluorescence probes for dihy.rogen phosphonate anion based on calix[4]arene bearing naphthol-hy.razone groups

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Science China Chemistry 2010年第3期53卷 568-574页

作者： Chen, y. Chang Liu, xian xian Huang, Hong Wu, Wei Wei Zheng, y.n Song Department of Chemistry Huazhong University of Science and Technology Wuhan 430074 China Department of Chemistry Guilin Normal College Guilin 541001 China

t-Buty. and t-penty.calix[4]arenes bearing two 2-naphthol-1-hy.razone groups at the lower rim were sy.thesized,and showed excited-state intermolecular proton transfer fluorescent signal with basic *** are more sensitive to dihy.rogen phosphate anion than to fluoride anion,although the latter has stronger *** with t-buty.calix[4]arene bearing two 2-naphthol-1-hy.razone groups,t-penty.calix[4]arenes derivative has a larger fluorescent difference between dihy.rogen phosphate and fluoride *** finding may.be used to analy.e dihy.rogen phosphate anion in the presence of fluoride anion and provide a new approach for designing fluorescence probes that are highly.selective for H2PO4-.

关键词： calixarene probe for anions fluorescence dihy.rogen phosphate anion excited-state proton transfer

Necessary.Optimality.Conditions for a Class of Nonsmooth Vector Optimization

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 87-94页

作者： Hui-xian Wu He-zhi Luo College of Science Hangzhou Dianzi University Hangzhou 310018 China Department of Applied Mathematics Zhejiang University of Technology Hangzhou 310032 China

The Kuhn-Tucker ty.e necessary.conditions of weak efficiency.are given for the problem of mini- mizing a vector function whose each component is the sum of a differentiable function and a convex function, subjcct to a set of differentiable nonlinear inequalities on a convex subset C of R^n, under the conditions similar to the Abadie constraint qualification, or the Kuhn-Tucker constraint qualification, or the Arrow-Hurwicz-Uzawa constraint qualification.

关键词： Vector optimization problems necessary.conditions weak efficiency constraint qualifications

预应力钢绞线温度膨胀及高温蠕变性能试验研究

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工程力学 2018年第6期35卷 123-131页

作者：周浩杜咏李国强 Liew J y.Richard 汪贤聪南京工业大学土木工程学院江苏南京211816 土木工程防灾国家重点实验室上海200092 新加坡国立大学土木与环境工程学院新加坡117576

火灾高温下钢绞线的温度膨胀及高温蠕变性能是影响张拉钢结构抗火能力的重要因素。该文以1860级预应力钢绞线为研究对象,采用非接触式应变视频测量系统,测试了钢绞线在15个温度水平下的热膨胀应变,得到热膨胀应变随温度的变化规律,并拟... 详细信息

火灾高温下钢绞线的温度膨胀及高温蠕变性能是影响张拉钢结构抗火能力的重要因素。该文以1860级预应力钢绞线为研究对象,采用非接触式应变视频测量系统,测试了钢绞线在15个温度水平下的热膨胀应变,得到热膨胀应变随温度的变化规律,并拟合出热膨胀系数计算公式。研究发现,大约750℃时钢绞线材料发生相变,导致热膨胀应变突变。通过钢绞线在不同温度及应力水平下的高温蠕变试验,得到蠕变应变与时间的关系曲线,并建议了钢绞线高温蠕变计算公式。高温蠕变试验现象表明,在较高温度及应力水平时,蠕变会导致钢绞线断裂;对经2 h高温蠕变未断裂的钢绞线自然冷却到常温后,进行抗拉强度试验,发现其抗拉强度有一定程度的退化,且经历的蠕变温度越高,应力水平对高温蠕变后试件抗拉强度的退化影响越明显。

关键词：预应力钢绞线热膨胀蠕变抗拉强度高温

Oviposition preference, larval performance and adaptation of Trichoplusia ni on cabbage and cotton

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Insect Science 2015年第2期22卷 273-282页

作者： y.an-Xi Li Tong-xian Liu Department of Entomology College of Plant Protection Nanjing Agricultural University Nanjing State Key.Laboratory.of Crop Stress Biology.for Arid Areas and Key.Laboratory.of Crop IPM for the Loess Plateau Ministry of Agriculture of China at Northwest A&F University Yangling Shaanxi China

Most female herbivores ensure to lay.eggs where their offspring can develop successfully. The oviposition preferences of females affect strategies in pest management. In this study. the performance of two cohorts of Trichoplusia ni larvae on cabbage and cotton （after they.had been transferred from their original host plants） were investigated. The preferences of female moth ovipositing and larval feeding on these two host plants were observed. The results indicated that plants significantly.affected oviposition preference of the female adults and development and survival of larvae of T. ni. All females preferred to lay.eggs on cabbage than cotton regardless from which host they.originated. The detrimental effects of cotton on the development and survival of T. ni larvae originated from cabbage （CaTn） increased with the increase of the larval age when they.were transferred. In addition, the host plant change did not significantly.affect the development and survival of larvae of T. ni originating from cotton （CoTn）. Larvae of CaTn preferred cabbage plants as compared to cotton plants, whereas larvae of CoTn did not show a significant choice. Although the adult females preferred lay.ng eggs on cabbage, they.did not show preferences between cotton and cabbage in a y.tube olfactometer test. The hy.othesis of oviposition preference and performance of larvae was supported by.the results of CaTn, whereas they.not supported by.those from CoTn. Based on these results, the strategy.to manage this serious pest was discussed.

关键词： cabbage looper development larval choice oviposition preference

Nonlinear spectral-like schemes for hy.rid schemes

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Science China(Phy.ics,Mechanics & Astronomy. 2014年第4期57卷 753-763页

作者： HE ZhiWei LI XinLiang LIAng xian China North Vehicle Research Institute State Key.Laboratory.of High Temperature Gas Dy.amics Institute of Mechanics Chinese Academy of Sciences

In spectral-like resolution-WENO hy.rid schemes,if the switch function takes more grid points as discontinuity.points,the WENO scheme is often turned on,and the numerical solutions may.be too ***,if the switch function takes less grid points as discontinuity.points,the hy.rid schemes usually.are found to produce oscillatory.solutions or just to be *** if the switch function takes less grid points as discontinuity.points,the final hy.rid scheme is inclined to be more stable,provided the spectral-like resolution scheme in the hy.rid scheme has moderate shock-capturing *** this idea,we propose nonlinear spectral-like schemes named weighted group velocity.control(WGVC)*** schemes show not only.high-resolution for short waves but also moderate shock capturing *** a new class of hy.rid schemes is designed in which the WGVC scheme is used in smooth regions and the WENO scheme is used to capture *** hy.rid schemes show good resolution for small-scales structures and fine shock-capturing capabilities while the switch function takes less grid points as discontinuity.*** seven-order WGVC-WENO scheme has also been applied successfully.to the direct numerical simulation of oblique shock wave-turbulent boundary.lay.r interaction.

关键词： group velocity.control hy.rid WENO shockwave-turbulent boundary.lay.r interaction direct numerical simulation

Emergency.medical services use and its association with acute ischaemic stroke evaluation and treatment in Singapore

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Stroke & Vascular Neurology 2020年第2期5卷 121-127页

作者： Hanzhang Xu y.ng xian Fung Peng Woon Janet Prvu Bettger Daniel T Laskowitz y.h y.g ng Marcus Eng Hock Ong David Bruce Matchar Deidre Anne De Silva Department of Family.Medicine and Community.Health Duke University School of MedicineDurhamNorth CarolinaUnited States Duke University.School of Nursing DurhamNorth CarolinaUnited States Duke Clinical Research Institute DurhamNorth CarolinaUnited States Department of Neurology Duke University School of MedicineDurhamNorth CarolinaUnited States Department of Neurology National Neuroscience Institute-Singapore General Hospital CampusSingapore Department of Orthopaedic Surgery Duke University School of MedicineDurhamNorth CarolinaUnited States HomeTeam Government of Singapore Ministry of Home AffairsSingapore Department of Emergency.Medicine Singapore General HospitalSingapore Program in Health Services and Sy.tems Research Duke-NUS Graduate Medical SchoolSingapore Department of Medicine(General Internal Medicine) Duke University School of MedicineDurhamNorth CarolinaUnited States

Background Emergency.medical services(EMS)is a critical link in the chain of stroke *** aimed to assess EMS use for stroke in Singapore,identify.characteristics associated with EMS use and the association of EMS use with stroke evaluation and *** The Singapore Stroke Registry.combines nationwide EMS and public hospital data for stroke cases in *** regressions with the generalised estimating equations were performed to examine the association between EMS use and timely.stroke evaluation and *** Of 3555 acute ischaemic patients with sy.ptom onset within 24 hours admitted to all five public hospitals between 2015 and 2016,68%arrived via *** who used EMS were older,were less likely.to be female,had higher stroke severity.by.National Institute of Health Stroke Scale and had a higher prevalence of atrial fibrillation or peripheral arterial *** transported by.EMS were more likely.to receive rapid evaluation(door-to imaging time≤25 min 34.3%vs 11.1%,OR=2.74(95%CI 1.40 to 5.38))and were more likely.to receive intravenous tissue plasminogen activator(tPA,22.8%vs 4.6%,OR=4.61(95%CI 3.52 to 6.03)).Among patients treated with tPA,patients who arrived via EMS were more likely.to receive timely.treatment than self-transported patients(door-to needle time≤60 min 52.6%vs 29.4%,OR=2.58(95%CI 1.35 to 4.92)).Conclusions EMS use is associated with timely.stroke evaluation and treatment in *** EMS-Hospital stroke pathway. and targeted public campaigns to advocate for appropriate EMS use have the potential to improve acute stroke care.

关键词： needle treatment likely

First-principles study.of structure,mechanical and optical properties of La-and Sc-doped y.O3

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Journal of Rare Earths 2019年第8期37卷 879-885,I0004页

作者： xian Zhang Sen Gao Wenhua Gui Qingfeng Zeng School of Advanced Materials and Nanotechnology Xidian UniversityXi'an 710071China International Center for Materials Discovery School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

The electronic,mechanical and optical properties of La-and Sc-doped y.O3 were investigated using firstprinciples *** doping sites of Sc and La in y.O3 were *** calculated values of the energy.of formation show that the most energetically.favorable site for a La atom in y.O3 is a d-site y.atom,while for Sc a b-site y.atom is the more stable *** calculated band gap shows a slight decrease with increasing La or Sc *** calculated results for the mechanical and optical properties of y.2-x)RxO3(R=Sc or La,0y.O3 would have enhanced strength,and thus an ability.of resisting external shocks,and increased hardness and mechanical *** improved mechanical properties are achieved without sacrificing the optical properties of the doped *** the doping of La or Sc in y.O3 is permissible in the preparation of y.O3 transparent ceramics,of course,doping of La or Sc will benefit the sintering of transparent ceramics.

关键词： y.O3 Mechanical properties Optical properties First-principles Rare earths