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Soliton resolution and asymptotic stability of n-solutions for the defocusing Kundu–Eckhaus equation with nonzero boundary conditions

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Communications in Theoretical Physics 2024年第1期76卷 1-6页

作者： Engui Fan y.nxi zhang School of Mathematical Sciences and Key Laboratory of Mathematics for nonlinear Science Fudan UniversityShanghai200433China Tianjin Xinhua High School No.99 machang RoadTianjin300204China

In this paper,we address interesting soliton resolution,asymptotic stability of n-soliton solutions and the Painleve asymptotics for the Kundu-Eckhaus(KE)equation with nonzero boundary conditions iq_(t)+q_(xx)-2(l|q|^(2)-1)q+4β^(2)(lql^(4)-1)q+4iβ(lql^(2))_(x)q=0,q(x,0)=q_(0)(x)-±1,x→±∞.The key to proving these results is to establish the formulation of a Riemann-Hilbert(RH)problem associated with the above Cauchy problem and find its connection with the RH problem of the defocusing nLS *** the■-steepest descent method and the results of the defocusing nLS equation,we find complete leading order approximation formulas for the defocusing KE equation on the whole(x,t)half-plane including soliton resolution and asymptotic stability of n-soliton solutions in a solitonic region,Zakharov-Shabat asymptotics in a solitonless region and the Painlevéasymptotics in two transition regions.

关键词： defocusing Kundu-Eckhaus equation Riemann-Hilbert problems steepest descent method soliton resolution asymptotic stability Painleve transcendents

Sounding the alarm:Functionally referential signaling in Azure-winged Magpie

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Avian Research 2024年第1期15卷 35-41页

作者： Xingyi Jiang y.ny.n zhang Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijing 100875China

Functionally referential signals are a complex form of communication that conveys information about the external *** signals have been found in a range of mammal and bird species and have helped us understand the complexities of animal *** are well known for their extraordinary cognitive abilities,but relatively little attention has been paid to their vocal ***,we investigated the functionally referential signals of a cooperatively breeding corvid species,Azure-winged Magpie(Cy.nopica cy.nus).Through field observations,we suggest that Azure-winged Magpie uses referential alarm calls to distinguish two types of threats:’rasp’ calls for terrestrial threats and ’chatter’ calls for aerial threats.A playback experiment revealed that Azure-winged Magpies responded to the two call types with qualitatively different *** sought cover by fly.ng into the bushes in response to the ’chatter’ calls,and flew to or stayed at higher positions in response to ’rasp’ calls,display.ng a shorter response time to ’chatter’ *** differences in acoustic structure were found between the two types of *** the extensive cognitive abilities of corvids and the fact that referential signals were once thought to be unique to primates,these findings are important for expanding our understanding of social communication and language evolution.

关键词： Alarm call Animal communication Azure-winged Magpie Referential signal

Syntheses and properties of associative acrylamide copolymers containing short hydrophobic chains used in a friction reducer for slick-water fracturing

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Petroleum Science 2024年第3期21卷 1889-1901页

作者： ya-Xing Dai Xian-Li zhang Si-yuan Liu Feng-Run-Ze zhang yi-Xi zhang yu-Tong Sang Jing-Xi Zheng Zhao-Sheng Liu Peng zhang College of Chemistry and Chemical Engineering Chongqing University of Science and TechnologyChongqing401331China College of Ecology and Environment Chongqing Resources and Environmental Protection of UniversityChongqing401331China China China Property Project Department of Dezhou Mining Property Service CenterShengli Oilfield Company of SinopecDezhou253000ShandongChina

Two allyldimethylalkyl quaternary ammonium salt(AQAS)monomers,n,n-dimethylallylphenylpropylammonium bromide(AQAS1)and n,n-dimethylally.nonylammonium bromide(AQAS2),were synthesized and used to prepare modified polyacrylamide *** new drag reducers were synthesized from acrylamide(AM),sodium acrylate(na AA)and a cationic modified monomer(AQAS1 or AQAS2)via aqueous solution polymerization,and the copolymers were named P(AM/na AA/AQAS1)and P(AM/na AA/AQAS2),*** structures of the drag reduction agents were confirmed by IR and1H nMR *** molecular weight(Mw)of P(AM/na AA/AQAS1)was 1.79×10^(6)g/*** the copolymer concentration was 1000 mg/L and the flow rate was 45 L/min,in fresh water the highest drag reduction rate was 75.8%,in 10,000 mg/L na Cl solution the drag reduction rate decreased to 72.9%.The molecular weight of P(AM/na AA/AQAS2)was 3.17×10^(6)g/*** the copolymer concentration was500 mg/L and the flow rate was 45 L/min,the drag reduction rate reached 75.2%,and in 10,000 mg/L na Cl solution the drag reduction rate was 73.3%,decreased by approximately 1.9%.The drag reduction rate for partially hydrolyzed polyacrylamide(HPAM)was also investigated,and the results showed that the drag reduction rates for 500 and 1000 mg/L HPAM solutions were merely 43.2%and 49.0%in brine,*** with HPAM,both of the above copolymers presented better drag reduction capacities.

关键词： Shale gas Slick water Drag reducer Modified monomer Copolymerization

On limit fractional Volterra hierarchies

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Communications in Theoretical Physics 2024年第1期76卷 7-16页

作者： Lixiang zhang Chuanzhong Li School of Mathematics and Statistics Ningbo UniversityNingbo315211China College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao266590China

For the limit fractional Volterra(LFV)hierarchy,we construct the n-fold Darboux transformation and the soliton ***,we extend the LFV hierarchy to the noncommutative LFV(nCLFV)hierarchy,and construct the Darboux transformation expressed by quasi determinant of the noncommutative ***,we establish the relationship between new and old solutions of the nCLFV ***,the quasi determinant solutions of the nCLFV hierarchy are obtained.

关键词： limit fractional Volterra hierarchy noncommutative limit fractional Volterra hierarchy Darboux transformation soliton solution quasi determinant solution

Elucidation of the last steps of photo-ammonification:analytical method development and mechanism elucidation

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 101-106页

作者： y.ngjing Miao Hui Wang Chunpeng y.ng Ruochun zhang Hao zhang Peizhe Sun School of Environmental Science and Engineering Tianjin UniversityTianjin 300072China SInOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China School of Earth System Science Tianjin UniversityTianjin 300072China

The mechanisms underly.ng the photo-ammonification of nitrogenous organic compounds(nOCs)remain unclear,partly due to the analytical challenges of small nOC *** study introduced a simple methodology for accurately and simultaneously quantify.ng multiple small nOCs during ammonification *** developed method employed phenyl isothiocy.nate as derivatization reagents,followed by high-performance liquid chromatography analysis to measure primary and secondary amines,amides,as well as nH4+over variable photo-ammonification *** our experimental setup,vacuum ultraviolet(VUV)irradiation serves as the controlled reaction environment to simulate harsh photo-ammonification *** nOCs,including pyridine,n,n-dimethylformamide,and acrylonitrile,were chosen due to their structural diversity and environmental relevance as model *** method was able to achieve excellent nitrogen mass balance,and revealed that the last steps of photo-ammonification involved oxidation of nitrogen-adjacent carbon to amide followed by the cleavage of n-C *** novel method may also help quantitative investigation of nitrogen transformations in different environmental contexts.

关键词： Ammonification nOCs Amines nitrogen mass balance

Exploration of the Existence Forms and Patterns of Dissolved Oxygen Molecules in Water

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nano-Micro Letters 2024年第10期16卷 337-349页

作者： Hewei yuan yaozhong zhang Xiaolu Huang Xiwu zhang Jinjin Li yufeng Huang Kun Li Haotian Weng y.ng Xu yafei zhang Key Laboratory of Thin Film and Microfabrication(Ministry of Education) Department of Micro/Nano ElectronicsSchool of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240People's Republic of China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China Jinduo yuchen Water Environment Engineering Co. LtdShanghai 201702People's Republic of China

The structure of liquid water is primarily composed of three-dimensional networks of water clusters formed by hydrogen bonds,and dis-solved oxygen is one of the most important indicators for assessing water *** this work,distilled water with different concentration of dissolved oxygen were prepared,and a clear negative correlation between the size of water clus-ters and dissolved oxygen concentration was ***,a phenomenon of rapid absorption and release of oxygen at the water interfaces was unveiled,suggesting that oxygen molecules predominantly exist at the interfaces of water *** molecules can move rapidly through the interfaces among water clusters,allowing dissolved oxygen to quickly reach a saturation level at certain partial pressure of oxygen and *** exploration into the mechanism by molecular dynamics simulations of oxygen and water clusters found that oxygen molecules can only exist stably at the interfaces among water clusters.A semi-empirical formula relating the average number of water molecules in a cluster(n)to ^(17)O nMR half-peak width(W)was summarized:n=0.1 W+*** findings provide a foundation for exploring the structure and properties of water.

关键词： Water clusters Dissolved oxygen ^(17)O nMR Molecular dynamics simulation

Effect of Frequency on Degradation in BOPP Films Under Repetitively Pulsed Voltage

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1280-1290页

作者： Chuansheng zhang yu Feng Fei Kong Bangdou Huang Cheng zhang Tao Shao Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Operating conditions of film capacitors are complex,and the problem of film insulation failure caused by repetitively pulsed voltage is becoming ever *** of the film under repetitively pulsed voltage cannot be accurately evaluated by the average breakdown electric *** this paper,the effects of pulsed electric field and pulse repetition frequency on the breakdown in biaxially oriented polypropylene(BOPP)films are *** phases of BOPP degradation are proposed based on the voltage amplitude,i.e.,maintenance(M),decline(D),and near-zero(n).Evolution of the BOPP film from degradation to breakdown at different frequencies is ***,transition of discharge mode and elemental composition of the film are *** results show continuous heat generation under repetitive microsecond pulses is the dominant factor for degradation of BOPP *** number of applied pulses and the repetitive stressing time decrease exponentially with increase of *** research can be contributed to the safe and reliable operation of capacitors.

关键词： Aging breakdown film capacitor polypropylene repetitive pulse

Compact ultrafast neutron sources via bulk acceleration of deuteron ions in an optical trap

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Matter and Radiation at Extremes 2024年第5期9卷 22-31页

作者： Zhiyu Lei Hanghang Ma Xiaobo zhang Lin yu yihang zhang yutong Li Suming Weng Min Chen Jie zhang Zhengming Sheng Key Laboratory for Laser Plasmas and School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Centre of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 201210China College of Physics and Electronics Engineering Northwest Normal UniversityLanzhou 730070China Beijing national Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

A scheme for a quasi-monoenergetic high-flux neutron source with femtosecond duration and highly anisotropic angular distribution is *** scheme is based on bulk acceleration of deuteron ions in an optical trap or density grating formed by two counter-propagating laser pulses at an intensity of-10^(16)W~cm^(2)in a near-critical-density *** deuterons are first pre-accelerated to an energy of tens of keV in the ambipolar fields formed in the optical *** energy is boosted to the MeV level by another one or two laser pulses at an intensity of-10^(20)W~cm^(2),enabling fusion reactions to be triggered with high *** contrast to previously proposed pitcher–catcher configurations,our scheme can provide spatially periodic acceleration structures and effective collisions between deuterons inside the whole target ***,neutrons are generated directly inside the optical *** simulations show that neutron pulses with energy 2–8 MeV,yield 10^(18)–10^(19)n/s,and total number 106–107 in a duration-400 fs can be obtained with a 25μm ***,the neutron pulses exhibit unique angularly dependent energy spectra and flux distributions,predominantly along the axis of the energy-boosting *** microsize femtosecond neutron pulses may find many applications,such as high-resolution fast neutron imaging and nuclear physics research.

关键词： acceleration scheme angular

Synergistic enhancement on mechanical properties and corrosion resistance of biodegradable Mg-Zn-y alloy via V-microalloy.ng

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Journal of Magnesium and Alloys 2024年第2期12卷 530-545页

作者： Jiaxin zhang Xin Ding Ruirun Chen Wenchao Cao Jinshan zhang Rui Zhao national Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyNo.92West Dazhi StreetHarbinHeilongjiang 150001China College of Materials Science and Engineering Taiyuan University of TechnologyNo.79West Yingze StreetTaiyuanShanxi 030024China

For the sake of improving the mechanical properties and corrosion resistance of biodegradable Mg alloy synergistically,various content of element V(0,0.05,0.10,0.15,0.20 wt.%)are introduced into an Mg-Zn-y alloy with long-period stacking ordered(LPSO)structure,and the effects of V on its microstructure,mechanical properties and corrosion resistance are investigated *** results indicate that the grains are effectively refined by V addition,and the primaryα-Mg in Mg-Zn-y-V0.1 alloy is most significantly refined,with grain size being decreased by 62%.The amount of 18R LPSO structure is increased owing to the V *** growth mode of the second phase(W-phase and 18R LPSO structure)is transformed to divorced growth pattern,which ascribes to the thermodynamic drive force of V to promote the nucleation of LPSO ***,18R LPSO structure presents a continuous *** to grains refinement and modification of second phase,the tensile strength and strain of alloys are both enhanced ***,the ultimate tensile strength and the elongation of V0.1 alloy are 254 MPa and 15.26%,which are 41%and 61%higher than those of V-free alloy,*** to the continuously distributed 18R LPSO structure with refined grains and stable product film,the weight loss and hydrogen evolution corrosion rates of V0.1 alloy are 7.1 and 6.2 mmy^(-1),respectively,which are 42.6%and 45.4%lower than those of V-free alloy.

关键词： Corrosion Mechanical property V-microalloy.ng LPSO SKPFM