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In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.lv H.l.Ge Q.Q.Jin X.H.Shao Y.T.Zhou B.zhang X.l.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation Hardening Precipitates In-situ TEM

Hydrochemical Characteristics and Evolution of Underground Brine in lop Nur,Northwestern China

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 786-800页

作者： BO Ying lIU Chenglin JIAO Pengcheng lU Fenglin zhang Hua MNR Key laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

lop Nur is located at the eastmost end of the Tarim Basin in Xinjiang,Northwestern *** study reviews the hydrochemical characteristics and evolution of underground brine in lop Nur,based on analytical data from 429 water samples(mainly brine).It is found that in the NE-SW direction,from the periphery to the luobei sub-depression,while the hydrochemical type varies from the sodium sulfate subtype(S)to the magnesium sulfate subtype(M),the corresponding brine in the phase diagram transfers from the thenardite phase(Then)area,through the bloedite phase(Blo),epsomite phase(Eps),picromerite phase(Picro),finally reaching the sylvite phase(Syl)*** for the degree of evolution,the sequence is the peripheryluobei horizontally and the overlying glauberite brinelying clastic brine *** is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude,as well as the changes in local water circulation in recent *** and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic *** strontium isotopic composition indicates that the lop Nur brine primarily originates from surface water;however,deep recharge may also be involved in the evolution of the brine,according to previous noble gas *** is confirmed that the brine in lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's *** on chemical compositions of brine from drillhole lDK01 and previous lithological studies,the evolution of the salt lake can be divided into three stages and it is inferred that the brine in lop Nur may have undergone at least two significant concentration-dilution periods.

关键词： brine evolution isotope enrichment potassium lop Nur

Effect of samarium doping on the activity and sulfur resistance of Ce/MnFeO_(x) catalyst for low-temperature selective catalytic reduction of NO_(x) by ammonia

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Chinese Journal of Chemical Engineering 2024年第7期71卷 272-282页

作者： Qiyao zhang Shuangshuang zhang Xu Hu Yongmin Huang Key laboratory of Specially Functional Polymeric Materials and Related Technology School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

The self-made MnFeO_(x) catalysts doped with cerium and samarium were prepared by impregnation method for low-temperature selective catalytic reduction(SCR)by *** this work,the surface properties of the series of MnFe-based catalysts were *** results indicate Sm-modified catalyst have superior low-temperature SCR activity;NO_(x) conversion maintained at nearby to 100%at 90℃ to 240℃.In addition,The N_(2) selectivity of Sm doping remains above 80%in the range of 60℃ to 150℃.In SO_(2) poisoning test,the NO_(x) conversion can be remained>90%after 10 h of *** XPS,NH_(3)-TPD and H_(2)-TPR results show the catalyst with Sm doping enhances the acid sites and oxidation catalytic sites of mixed oxides serves for improving oxygen vacancies and transfer *** situ diffuse reflaxions infrared Fourier transformations spectroscopy(DRIFTS)results show that NO_(x) is more easily adsorbed on the surface after Sm doping,which provided favorable conditions for the NH_(3)-SCR reaction to *** reaction at the catalyst surface will follow the l-H reaction mechanism by transient reaction test.

关键词： SCR Sm doping Catalyst Sulfur resistance In situ DRIFTS Selectivity

Distributed Multicircular Circumnavigation Control for UAVs with Desired Angular Spacing

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Defence Technology（防务技术） 2024年第1期31卷 429-446页

作者： Shixiong li Xingling Shao Wendong zhang Qingzhen zhang National Key laboratory for Electronic Measurement Technology School of Instrument and ElectronicsNorth University of ChinaTaiyuan 030051China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100086China

This paper addresses a multicircular circumnavigation control for UAVs with desired angular spacing around a nonstationary *** defining a coordinated error relative to neighboring angular spacing,under the premise that target information is perfectly accessible by all nodes,a centralized circular enclosing control strategy is derived for multiple UAVs connected by an undirected graph to allow for formation behaviors concerning the moving ***,to avoid the requirement of target’s states being accessible for each UAV,fixed-time distributed observers are introduced to acquire the state estimates in a fixed-time sense,and the upper boundary of settling time can be determined offline irrespective of initial properties,greatly releasing the burdensome communication ***,with the aid of fixed-time distributed observers,a distributed circular circumnavigation controller is derived to force all UAVs to collaboratively evolve along the preset circles while keeping a desired angular *** is inferred from lyapunov stability that all errors are demonstrated to be *** are offered to verify the utility of proposed protocol.

关键词： Angular spacing Distributed observer Multicircular circumnavigation Moving target UAVs

Plant Chemical Defenses against Insect Herbivores—Using theWild Tobacco as a Model

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Phyton-International Journal of Experimental Botany 2024年第4期93卷 641-659页

作者： Guangwei Sun Xuanhao zhang Yi liu liguang Chai Daisong liu Zhenguo Chen Shiyou lü Hubei Provincial Tobacco Research Institute Wuhan430030China Shiyan Branch of Hubei Tobacco Company Shiyan442000China State Key laboratory of Biocatalysis and Enzyme Engineering School of Life SciencesHubei UniversityWuhan430062China

The Nicotiana genus, commonly known as tobacco, holds significant importance as a crucial economic crop. Confrontedwith an abundance of herbivorous insects that pose a substantial threat to yield, tobacco has developed adiverse and sophisticated array of mechanisms, establishing itself as a model of plant ecological defense. Thisreview provides a concise overview of the current understanding of tobacco’s defense strategies against *** defenses, exemplified by its well-known tactic of secreting the alkaloid nicotine, serve as a potent toxinagainst a broad spectrum of herbivorous pests. Moreover, in response to herbivore attacks, tobacco enhancesthe discharge of volatile compounds, harnessing an indirect strategy that attracts the predators of the *** delicate balance between defense and growth leads to the initiation of most defense strategies only after aherbivore attack. Among plant hormones, notably jasmonic acid (JA), play central roles in coordinating thesedefense processes. JA signaling interacts with other plant hormone signaling pathways to facilitate the extensivetranscriptional and metabolic adjustments in plants following herbivore assault. By shedding light on these ecologicaldefense strategies, this review emphasizes not only tobacco’s remarkable adaptability in its natural habitatbut also offers insights beneficial for enhancing the resilience of current crops.

关键词： Tobacco herbivore chemical defense jasmonic acid regulation

Iron–doped bismuth oxybromides as visible-light-responsive Fenton catalysts for the degradation of atrazine in aqueous phases

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Journal of Environmental Sciences 2024年第3期137卷 321-332页

作者： Yong-li Cai Yu-Hang Xu Ji-Zun Xiang Zhi-Qiang zhang Qiu-Xiang He Ya-Feng li Jian lü Fujian Provincial Key laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Pesticides and its degradation products,being well–known residues in soil,have recently been detected in many water bodies as pollutants of emerging concerns,and thus there is a contemporary demand to develop viable and cost–effective techniques for the removal of related organic pollutants in aqueous ***,a visible-light-responsive Fenton system was constructed with iron–doped bismuth oxybromides(Fe–BiOBr)as the *** the advantage of sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion and optimized H_(2)O_(2)utilization,the optimal Fe–BiOBr–2 catalyst showed an excellent atrazine removal efficiency of 97.61%in 120 min,which is superior than the traditional homogeneous Fenton and the majority of heterogeneous processes documented in the *** this photo–Fenton system,hydroxyl(·OH)and superoxide(·O_(2)^(-))radicals were dominant active species contributed to the oxidative degradation of *** to the production of various active radicals,five degradation pathways were proposed based on the identification of intermediates and degradation ***,this work not only demonstrates a fundamental insight into creating highly efficient and atom economic photo-Fenton systems,but also provides a complementary strategy for the treatment of organic pollutants in water.

关键词： Bismuth oxybromide Photo–Fenton Atrazine Catalytic degradation

Characterization of local chemical ordering and deformation behavior in high entropy alloys by transmission electron microscopy

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 877-886页

作者： Qiuhong liu Qing Du Xiaobin zhang Yuan Wu Andrey A.Rempel Xiangyang Peng Xiongjun liu Hui Wang Wenli Song Zhaoping lü Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences Ekaterinburg 620016Russia China Nuclear Power Technology Research Institute Co.ltd. Shenzhen 518000China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China

Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied *** electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex *** this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of *** using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was ***,the perspective related to application of TEM techniques in HEAs are also discussed.

关键词： high entropy alloys transmission electron microscopy short-range ordering deformation mechanisms

Digital generation of super-Gaussian perfect vortex beams via wavefront shaping with globally adaptive feedback

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High Power laser Science and Engineering 2024年第1期12卷 42-51页

作者： Rui Ma Ke Hai luo Jing Song He Wei li zhang Dian Yuan Fan Anderson S.l.Gomes Jun liu International Collaborative laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhenChina Institute for Advanced Study Shenzhen UniversityShenzhenChina Fiber Optics Research Centre School of Information and Communication EngineeringUniversity of Electronic Science and Technology of ChinaChengduChina Departamento de Física Universidade Federal de PernambucoRecife-PEBrazil

High-intensity vortex beams with tunable topological charges and low coherence are highly demanded in applications such as inertial confinement fusion(ICF) and optical communication. However, traditional optical vortices featuring nonuniform intensity distributions are dramatically restricted in application scenarios that require a high-intensity vortex beam owing to their ineffective amplification resulting from the intensity-dependent nonlinear effect. Here, a low-coherence perfect vortex beam(PVB) with a topological charge as high as 140 is realized based on the super-pixel wavefront-shaping technique. More importantly, a globally adaptive feedback algorithm(GAFA) is proposed to efficiently suppress the original intensity fluctuation and achieve a flat-top PVB with dramatically reduced beam speckle contrast. The GAFA-based flat-top PVB generation method can pave the way for high-intensity vortex beam generation,which is crucial for potential applications in ICF, laser processing, optical communication and optical trapping.

关键词： digital micromirror device flat-top beam orbital angular momentum perfect vortex beam random fiber laser

A Possible γ-Ray Pulsation from PSR J1740-5340B in the Globular Cluster NGC 6397

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Research in Astronomy and Astrophysics 2024年第1期24卷 285-291页

作者： Jiao Zheng Pengfei zhang li zhang Department of Astronomy School of Physics and AstronomyKey Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China

Recently, a new radio millisecond pulsar(MSP) J1740-5340B, hosted in the globular cluster(GC) NGC 6397,was reported with a 5.78 ms spin period in an eclipsing binary system with a 1.97 days orbital period. Based on a modified radio ephemeris updated by tool tempo2, we analyze the ~15 yr γ-ray data obtained from the large Area Telescope on board the Fermi Gamma-ray Space Telescope and detect PSR J1740-5340B's γ-ray pulsation at a confidence level of ~4σ with a weighted H-test value of ~26. By performing a phase-resolved analysis, the γ-ray luminosity in on-pulse interval of PSR J1740-5340B is l_(γ)~ 3.8 × 10^(33) erg s^(-1) using NGC 6397's distance of 2.48 kpc. And γ-rays from the on-pulse part of PSR J1740-5340B contribute ~90% of the total observed γ-ray emissions from NGC 6397. No significant γ-ray pulsation of another MSP J1740-5340A in the GC is *** that the previous four cases of MSPs in GCs, more data in γ-ray, X-ray, and radio are encouraged to finally confirm the γ-ray emissions from MSP J1740-5340B, especially starving for a precise ephemeris.

关键词： gamma-rays:galaxies (stars:)pulsars:individual(PSR J1740-5340B) (Galaxy:)globular clusters:individual(NGC 6397)