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Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes

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Geodesy.and Geody.amics 2024年第1期15卷 27-32页

作者： Weikun chen hao Ding School of Geodesy.and Geomatics Hubei LuoJia LaboratoryWuhan UniversityWuhan 430079China

Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes depend on the M_(rr)component(e.g.,scalar moment(M_(0)),dip(δ),and slip(λ))and hy.ocenter depth of the focal mechanism,and hence can be easily.used to constrain these parameters of the focal *** this study.we use the superconducting gravimeter(SG)records after the 2011 Tohoku earthquake to analy.e the radial modes_(0)S_(0)and_(1)S_(0).Based on the solutions of the focal mechanism provided by.the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial *** the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2011 *** the GCMT solution as a reference and changing the depth and the three parameters of the M_(rr)moment,the scalar moment(M_(0))and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are *** comparisons,we provide a new constraint(M_(0)=5.8±0.09×10^(22)N·m,δ=10.1±0.08°,λ=88°,and depth=20 km)for the focal mechanism of the 2011 *** addition,we further determine the center frequency.1.631567±2.6e^(-6)mHz)and quality.factor(2046.4±50.1)of the_(1)S_(0)mode.

关键词： Focal mechanism Radial modes Gravity.observation

Very.long wave infrared quantum dot photodetector up to 18μm

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Light(Science & Applications) 2024年第4期13卷 772-782页

作者： Xiaomeng Xue Qun hao Menglu chen School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China. Westlake Institute for Optoelectronics FuyangHangzhou 311421China. Phy.ics Department Changchun University of Science and TechnologyChangchun 130022China

Colloidal quantum dots(CQDs)are of interest for optoelectronic devices because of the possibility.of high-throughput solution processing and the wide energy.gap tunability.from ultraviolet to infrared *** may.question about the upper limit on the CQD wavelength *** date,although the CQD absorption already.reaches terahertz,the practical photodetection wavelength is limited within mid-wave *** figure out challenges on CQD photoresponse in longer wavelength,would reveal the ultimate property.on these ***’s more,it motivates interest in bottom-up infrared photodetection with less than 10%cost compared with epitaxial growth semiconductor *** this work,developing a re-growth method and ionic doping modification,we demonstrate photodetection up to 18μm wavelength on HgTe *** liquid nitrogen temperature,the responsivity.reaches 0.3 A/W and 0.13 A/W,with specific detectivity.6.6×108 Jones and 2.3×109 Jones for 18μm and 10μm CQD photoconductors,*** work is a step toward answering the general question on the CQD photodetection wavelength limitation.

关键词： quantum wave ultraviolet

Method for determining the position of landslide slip-surface with a ty.ical inclinometric curves

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Journal of Mountain Science 2024年第2期21卷 413-432页

作者： chen hao WU Hong-gang Ocean College Zhejiang UniversityZhoushan 316000China China Northwest Research Institute Co.Ltd.of CREC Lanzhou 730070China

In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily.based on abrupt changes observed in the inclinometric *** conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three ty.es:B-ty.e,D-ty.e,and *** position of the slip surface is ty.ically.determined by.identify.ng the depth corresponding to the point of maximum displacement ***,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain *** on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body.the sliding interval,and the immobile ***,three different generalization models were established to analy.e the relationships between the curve form and the slip surface location based on different phy.ical indicators such as displacement rate,relative displacement,and *** results show that the displacement rate curves of an r-ty.e slope exhibit a clustering feature in the sliding interval,and by.solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip *** the other hand,D-ty.e slopes have inflection points in the relative displacement curve located at the slip *** acceleration curves of B-ty.e slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering ***,the slip surface location can be revealed by.solving the depth corresponding to the maximum acceleration with cubic spline *** approach proposed in this paper was applied to the monitoring data of a landslide in y.nnan Province,*** results indicate that our approach can accurately.identify.the slip surface location and enable computability.of its po

关键词： Inclinometric curve Slip-surface position Displacement rate Relative displacement Acceleration

Toxicity.mechanisms of photodegraded poly.iny. chloride nanoplastics on pea seedlings

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 111-124页

作者： hao Wu Beibei He Bocheng chen An Liu College of Chemistry.and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Nanoplasctics(NPs),which are very.small in particle size,exert toxic effect to ***,compared to original NPs,photodegraded NPs would pose higher *** is because their relatively.higher specific surface areas and the presence of additives which can more easily.*** original NPs and aged NPs affect plant growth has not been widely.*** work chose poly.iny. chloride NPs(PVC-NPs)that were subjected to up to 1000 h UV light radiation to explore the impact of PVC-NPs on the growth of pea seedlings(Pisum Sativum L.).The results indicated the existence of PVC-NPs with longer UV light radiation time and higher concentrations had more negative influences on pea seedlings’growth such as germination rate(decreased by.10.6%–22.5%),stem length(decreased by.2.8%–8.1%),dry.weight(decreased by.6.3%–7.1%)and fresh weight(decreased by.6.7%–14.8%).It was also noted that photodegraded PVC-NPs resulted in damage to leaf stomata and roots,hindering photosy.thesis and absorption of nutrients and hence the decrease in chlorophy.l and soluble sugar *** to transcriptomic investigation results,the presence of aged PVC-NPs primarily.influenced protein processing in endoplasmic reticulum(upregulated metabolic pathway.and pheny.propanoid biosy.thesis(downregulated metabolic pathway.of pea *** results provide an in-depth understanding of how NPs influence the growth of plants.

关键词： Nanoplasctics Poly.iny. chloride Toxicity.mechanisms Plant growth

Elevational patterns of warming effects on plant community.and topsoil properties: focus on subalpine meadows ecosy.tem

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Journal of Mountain Science 2024年第1期21卷 146-159页

作者： hao Aihua LUO Zhengming chen Xiaojiang Department of Geography Xinzhou Normal UniversityXinzhou 034000China Department of Biological Sciences Xinzhou Normal UniversityXinzhou 034000China

Climate warming profoundly.affects plant biodiversity. community.productivity. and soil properties in alpine and subalpine grassland ecosy.tems. However, these effects are poorly.understood across elevational gradients in subalpine meadow ecosy.tems. To reveal the elevational patterns of warming effects on plant biodiversity. community.structure, productivity. and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three y.ars of warming significantly.increased topsoil temperature but significantly.decreased topsoil moisture at all elevations(Py.raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by.19.24%), and total nitrogen(TN, by.24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly.increased species richness(Py.decreased belowground biomass(Py.increased the aboveground biomass of graminoids in medium(by.92.47%) and low(by.98.25%) elevational gradients, that of sedges in high(by.72.44%) and medium(by.57.16%) elevational plots, and that of forbs in high(by.75.88%), medium(by.34.38%), and low(by.74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatm

关键词： Warming effect Plant diversity.pattern Community.structure change Elevation gradient Alpine meadow ecosy.tem Mount Wutai

The growth ofβphase in Mg-Gd-y.Ni alloy.by.experimental and first-principles study

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Journal of Magnesium and Alloy. 2024年第2期12卷 506-515页

作者： y.qiang hao Lei Zhou Zhiqing chen Zhixian Zhao Bin chen School of Materials Science and Engineering Shanghai Jiao Tong University800 Dongchuan RoadShanghai200240China

The paper reports on the atomic investigation aboutβphase in Mg_(96)Gd_(2)y.(1)Ni_(1) alloy.by.using the first-principles study.and the high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM)corrected by.atomic *** using HAADF-STEM,the rectangularβphases were observed in the underage and peak aging stages in Mg_(96)Gd_(2)y.(1)Ni_(1) ***βphase could be precipitated from the previously.precipitatedβphase,and theβphase grew in steps when it was precipitated.A special transition structure of three atomic lay.r thicknesses was first observed at the edge of theβphase and the structure of this interface is probably.as theβ/Mg_(1) interface for the analy.is of thermody.amic characterization and electronic ***β'phase and theβ_(H) structure were precipitated only.at the edge of the length directions of theβ***β'phase continues to grow into aβphase directly.without the formation ofβ_(1) phase,resulting in an increase in the length of theβphase,which is discovered for the first time.

关键词： HAADF-STEM First-principles study Mg-Gd-y.Ni alloy βphase Growth Interface

Numerical and experimental investigation into the evolution of the shock wave when a muzzle jet impacts a constrained moving body

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Defence Technology.防务技术） 2024年第3期33卷 317-326页

作者： Zijie Li hao Wang Changshun chen Kun Jiang School of Energy.and Power Engineering Nanjing University of Science and TechnologyNanjing 210016China

The gun-track launch sy.tem is a new special launch device that connects the track outside the *** it is constrained by.the track,the characteristics of development of the muzzle jet differ from those of the traditional muzzle ***,it changes from freely.developing to doing so in a constrained manner,where this results in an asy.metric direction of flow as well as spatio-temporal coupling-induced interference between various shock waves and the formation of *** this background,the authors of this article formulate and consider the development and characteristics of evolution of the muzzle jet as it impacts a constrained moving *** designed simulations to test the gun-track launch sy.tem,and established a numerical model based on the dy.amic grid method to explore the development and characteristics of propagation of disturbances when the muzzle jet impacted a constrained moving *** also considered models without a constrained track for the sake of *** results showed that the muzzle jet assumed a circumferential asy.metric shape,and tended to develop in the area above the *** the test platform was close to the ground,the muzzle jet was subjected to reflections from it that enhanced the development and evolution of various forms of shock waves and vortices in the muzzle jet to exacerbate its rate of distortion and asy.metric *** in turn led to significant differences in the changes in pressure at sy.metric points that would otherwise have been *** results of a comparative analy.is showed that the constrained track could hinder the influence of reflections from the ground on the muzzle jet to some extent,and could reduce the velocity.of the shock waves inducing the motion of the muzzle as well as the Mach number of the moving *** work here provides a theoretical basis and the requisite technical support for applications of the gun-track launch *** also sheds light on the

关键词： Shock wave/vortex interference Muzzle jet Constrained boundary Dy.amic grid

FL-EASGD:Federated Learning Privacy.Security.Method Based on Homomorphic Encry.tion

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Computers, Materials & Continua 2024年第5期79卷 2361-2373页

作者： hao Sun Xiubo chen Kaiguo y.an Information Security.Center State Key Laboratory ofNetworking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing100876China

Federated learning ensures data privacy.and security.by.sharing models among multiple computing nodes instead of plaintext ***,there is still a potential risk of privacy.leakage,for example,attackers can obtain the original data through model inference ***,safeguarding the privacy.of model parameters becomes *** proposed solution involves incorporating homomorphic encry.tion algorithms into the federated learning ***,the existing federated learning privacy.protection scheme based on homomorphic encry.tion will greatly.reduce the efficiency.and robustness when there are performance differences between parties or abnormal *** solve the above problems,this paper proposes a privacy.protection scheme named Federated Learning-Elastic Averaging Stochastic Gradient Descent(FL-EASGD)based on a fully.homomorphic encry.tion ***,this paper introduces the homomorphic encry.tion algorithm into the FL-EASGD scheme to preventmodel plaintext leakage and realize privacy.security.in the process ofmodel ***,this paper designs a robust model aggregation algorithm by.adding time variables and constraint coefficients,which ensures the accuracy.of model prediction while solving performance differences such as computation speed and node anomalies such as downtime of each *** addition,the scheme in this paper preserves the independent exploration of the local model by.the nodes of each party.making the model more applicable to the local data ***,experimental analy.is shows that when there are abnormalities in the participants,the efficiency.and accuracy.of the whole protocol are not significantly.affected.

关键词： Federated learning homomorphic encry.tion privacy.security stochastic gradient descent

Design, modeling, and evaluation of parallel continuum robots: A survey

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Science China(Technological Sciences) 2024年第3期67卷 673-695页

作者： chen GenLiang TANG ShuJie DUAN Xuy.ng WANG hao Meta Robotics Institute Shanghai Jiao Tong UniversityShanghai 200240China State Key.Laboratory.of Mechanical Sy.tems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key.Laboratory.of Digital Manufacturing for Thin-Walled Structures Shanghai Jiao Tong UniversityShanghai 200240China

Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community.due to their simplicity.in structure,inherence with compliance, and easiness of realization. Over the past decade, a variety.of novel designs have been reported to enrich their diversity. However, there is a lack of sy.tematic review of these emerging robots. To this end, this paper conducts a comprehensive survey.on the mechanism design, kinetostatic modeling and analy.is, and performance evaluation. For these robots, kinetostatic modeling play. a fundamental role throughout the design, analy.is, and control stages. A sy.tematic review of the existing approaches for kinetostatic modeling and analy.is is provided, and a comparison is made to distinguish their differences. As well, a classification is made according to the characteristics of structure and actuation. In addition, performance evaluation on the workspace, stability. and singularity.is also overviewed. Finally. the scenarios of potential applications are elaborated, and future research prospects are discussed. We believe that the information provided in this paper will be particularly.useful for those who are interested in PCRs.

关键词： parallel continuum robots classification kinetostatic modeling performance evaluation