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Journal of Materials Science & Technology 2020年第19期54卷 132-143页

作者： H.Liu M.M.Xu S.Li z.b.bao S.L.zhu F.H.Wang Institute of Metal Research Chinese Academy of SciencesWencui Road 62#Shenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaJinzhai Road 96#Hefei 230026China Shenyang National Laboratory for Materials Science Northeastern UniversityWenhua Road 3#Shenyang 110819China

A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of *** order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the *** addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRz)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRz formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.

关键词： Ni_(3)Al-base superalloy Pt-modified aluminide coating Re-rich diffusion barrier Cyclic oxidation Interdiffusion Second reaction zone

Temperature Effect on Early Oxidation behavior of NiCoCrAlY Coatings: Microstructure and Phase Transformation

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Acta Metallurgica Sinica(English Letters) 2022年第6期35卷 975-984页

作者： A.Ullah A.Khan z.b.bao Y.F.Yang M.M.Xu S.L.zhu F.H.Wang University of Chinese Academy of Sciences Beijing 100049China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials Ministry of EducationSchool of Materials Science and EngineeringAnhui University of TechnologyMaanshan 243000China Institute of Advanced Wear and Corrosion Resistant and Functional Material Jinan UniversityGuangzhou 510632China Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang 110819China

Initial oxidation behavior of NiCoCrAlY coating prepared by arc-ion plating has been studied in air at 900, 1000 and 1100 ℃. The results showed that phase transformation from transient θ-Al_(2)O_(3) to α-Al_(2)O_(3) was highly related to the temperature and oxidation time. The oxide scale in the initial stage was mainly composed of θ-Al_(2)O_(3) at 900 ℃. Instead, more amount of α-Al_(2)O_(3) emerged out with increasing oxidation temperature. The elemental distribution after oxidation confirmed that faster chromium diffusion to the oxide scale played an important role in the speedy transformation from θ-Al_(2)O_(3) to α-Al_(2)O_(3). Y segregation at scale/coating interface resulted in less cavity formation and hence improved the oxide scale adherence.

关键词： MCrAlY coating Phase transformation Isothermal oxidation Temperature effect

Improved mass relations of mirror nuclei

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Nuclear Science and Techniques 2024年第9期35卷 178-185页

作者： Cheng Xu Man bao Department of Physics University of Shanghai for Science and TechnologyShanghai 200093China

In this study,we revisit the previous mass relations of mirror nuclei by considering 1/N-and 1/z-dependent terms and the shell effect across a *** root-mean-squared deviation is 66 keV for 116 nuclei with neutron number N≥10,as com-pared with experimental data compiled in the AME2020 *** predicted mass excesses of 173 proton-rich nuclei,including 98 unknown nuclei,are tabulated in the Supplemental Material herein with competitive accuracy.

关键词： Nuclear mass Mirror nuclei Proton-rich nuclei

Probing the bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R Wu b Q Wang z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric bardeen-Kiselev black hole(bH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the bardeen-Kiselev bH with the cosmological constant due to electromagnetic and gravitational *** varying the bH parameters,we discuss the behavior of both real and imaginary parts of the bH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter bH surrounded by quintessence(RN-dSQ).Interestingly,it is shown that the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the bardeen-Kiselev bH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the bardeen-Kiselev bH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors bardeen-Kiselev black hole with cosmological constant

Effect of Al_(2)O_(3)on the Mechanical Properties of(b_(4)C+Al_(2)O_(3))/Al Neutron Absorbing Materials

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai b.M.Shi N.Li Y.Liu z.G.zhang Y.N.zan Q.z.Wang b.L.Xiao z.Y.Ma Shi‑Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

b_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear *** order to improve the high-temperature mechanical properties of b_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder *** this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(b_(4)C+Al_(2)O_(3))/Al *** was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high *** the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased *** finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional b_(4)C/Al composites.

关键词： Al matrix composites Neutron absorbing materials (b_(4)C+Al_(2)O_(3))/Al composites High-temperature strength

An isolated symmetrical 2T2R cell enabling high precision and high density for RRAM-based in-memory computing

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Science China(Information Sciences) 2024年第5期67卷 287-294页

作者： Yaotian LING zongwei WANG Yuhang YANG Lin bao Shengyu bao Qishen WANG Yimao CAI Ru HUANG School of Integrated Circuits Beijing Advanced Innovation Center for Integrated Circuits Peking University State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

In-memory computing(IMC), leveraging emerging memories, holds significant promise in overcoming memory limitations and improving energy efficiency. However, the prevailing IMC array structure based on serially connected transistors and memory cells(1T1R/2T2R), along with the signed weight mapping scheme, can lead to asymmetrical weight sensing issues(AWS) due to electrical asymmetry within the1T1R/2T2R structure, particularly in highly scaled cells where the transistor's resistance becomes significant. In this paper, we propose and fabricate an electrically symmetric memory cell based on a physically isolated 2T2R structure for IMC. This design aims to enhance the precision and density of RRAM-based IMC arrays. The 2T2R cells are manufactured using the back-end-of-line(bEOL) process of a commercial40 nm technology platform. The feasibility of this design is verified through measured and simulated results,showcasing its capability to address the issue of AWS. Compared to conventional 2T2R cells, this design achieves a considerably smaller transistor footprint without compromising accuracy, while also improving integration density by 42.2%. These innovative memory cell advancements have the potential to further advance high-energy-efficient IMC technology.

关键词： RRAM 2T2R multi-level storage weight asymmetry in-memory computing

Research progress of slippage characteristic and gas film stability enhancement methods on biomimetic hydrophobic surfaces

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Journal of Hydrodynamics 2024年第1期36卷 87-101页

作者： Meng-zhuo zhang Hai-bao Hu Liu-zhen Ren Lu-yao bao Jun Wen Luo Xie School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China

The biomimetic hydrophobic surface is a potentially efficient underwater drag reduction method and the drag reduction mechanism of this kind of surface comes from the interfacial *** now,it is a hotspot to grasp the slippage characteristic and explore slippage enhancement *** paper not only summarizes our numerical simulation and experimental results of slippage characteristic at the solid-liquid interface(SLI)of hydrophobic surfaces(HS)and the gas-liquid interface(GLI)of superhydrophobic surfaces(SHS)in recent years,but also introduces some innovative methods that can effectively improve the gas film stability and drag reduction effect of ***,we used the molecular dynamics(MD)simulation method to figure out the effect of the solid-liquid interaction strength,the system temperature and the shear rate on the slippage of SLI,and expound their action mechanism from molecular ***,by MD and multibody dissipative particle dynamics(MDPD)method,the slippage behavior at the GLI was studied under the influence of the microstructure size and the flow driving *** proposed a new kind of hybrid slip boundary condition model to describe the slippage characteristic on *** addition,we found through experiment that a three-dimensional backflow will appear on the GLI under the interfacial adsorption of surfactants,and the backflow direction will reverse with the change of GLI ***,we put forward the wettability step structure and gas injection method to enhance the stability and drag reduction effect of the gas film on SHS.

关键词： Hydrophobic surface superhydrophobic surface interfacial slip underwater drag reduction

Exploring Variability in Sea Level at a Tide Gauge Station through Control Charts

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Journal of Environmental & Earth Sciences 2024年第1期6卷 11-18页

作者： H.bâkiİz Independent Scholar Boca Raton Florida33496USA

Monitoring temporal changes in sea level is important in assessing coastal *** level anomalies at a tide gauge station,if kinematically conceived,include systematic variations such as trend,acceleration,periodic oscillations,and random *** them,the non-stationary nature of the random sea level variations of known or unknown origin at coastal regions has been long recognized by the sea level *** study proposes the analyses of subgroups of random residual statistics of a rigorously formulated kinematic model solution of tide gauge variations using X-bar and S control *** approach is demonstrated using Key West,Florida tide gauge *** mean and standard errors of 5-year-long subgroups of the residuals revealed that sea level changes at this location have been progressively intensifying from 1913 to the *** oscillations in sea level at this locality may be attributed partly to the thermal expansion of seawater with increasing temperatures causing larger buoyancy-related sea level fluctuations as well as the intensification of atmospheric events including wind patterns and the impact of changes in inverted barometer effects that will alter coastal risk assessments for the future.

关键词： Climate change Sea level variance X-bar S control charts

Systematic study of the synthesis of heavy and superheavy nuclei in 48Ca-induced fusion-evaporation reactions

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Nuclear Science and Techniques 2024年第7期35卷 157-172页

作者： Shi-Hao zhu Tian-Liang zhao Xiao-Jun bao Department of Physics Collaborative Innovation Center for Quantum EffectsKey Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationHunan Normal UniversityChangsha410081China School of Nuclear Science and Technology Lanzhou UniversityLanzhou730000China School of Physics Xi’an Jiaotong UniversityXi’an710049China

We systematically studied the evaporation residue cross sections of ^(48)Ca-induced reactions on lanthanide and actinide target nuclei under the Dinuclear System(DNS)model framework to check the reliability and applicability of the *** produce new proton-rich Fl and Lv isotopes through hot fusion reactions in the superheavy element region with z≥104,we utilized the reactions ^(48)Ca+^(236,238,239) Pu and ^(48)Ca+^(242,243,244,250) ***,owing to the detection limit of available equipment(0.1 pb),only 283Fl and 287−289Lv,which have the maximum evaporation residue cross section values of 0.149,0.130,9.522,and 0.309 pb,respectively,can be ***,to produce neutron-deficient isotopes of actinides near the proton drip line with z=93−100,we attempted to generate the new isotopes(224−227Pu,228−232,237Cm)using the reactions ^(48)Ca+180,182,183 W and ^(48)Ca+^(184,186,187,192) *** maximum evaporation residue cross section values are 0.07,0.06,0.26,and 0.30 nb for the former set of reactions,and 1.96 pb,5.73 pb,12.16 pb,19.39 pb,54.79 pb,and 6.45 nb for the latter,*** results are expected to provide new information for the future synthesis of unknown neutron-deficient isotopes.

关键词： Dinuclear system(DNS)model Evaporation residue cross section Neutron-deficient isotopes

Fast and Adaptive Multi-Agent Planning under Collaborative Temporal Logic Tasks via Poset Products

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Research 2024年第2期2024卷 81-94页

作者： zesen Liu Meng Guo Weimin bao zhongkui Li Deparment of Mechanics and Engineering Science College of EngineeringPeking UniversityBejing 0081 China Science and Technology Commission of China Aerospace Science and Technology Corporation Beijing 100048China

Efficient coordination and planning is essential for large-scale multi-agent systems that collaborate in a shared dynamic environment. Heuristic search methods or learning-based approaches often lack the guarantee on correctness and performance. Moreover, when the collaborative tasks contain both spatial and temporal requirements, e.g., as linear temporal logic (LTL) formulas, formal methods provide a verifiable framework for task planning. However, since the planning complexity grows exponentially with the number of agents and the length of the task formula, existing studies are mostly limited to small artificial cases. To address this issue, a new planning paradigm is proposed in this work for system-wide temporal task formulas that are released online and continually. It avoids two common bottlenecks in the traditional methods, i.e., (a) the direct translation of the complete task formula to the associated b點hi automaton and (b) the synchronized product between the b點hi automaton and the transition models of all agents. Instead, an adaptive planning algorithm is proposed, which computes the product of relaxed partially ordered sets (R-posets) on-the-fly and assigns these subtasks to the agents subject to the ordering constraints. It is shown that the first valid plan can be derived with a polynomial time and memory complexity with respect to the system size and the formula length. Our method can take into account task formulas with a length of more than 400 and a fleet with more than 400 agents, while most existing methods fail at the formula length of 25 within a reasonable duration. The proposed method is validated on large fleets of service robots in both simulation and hardware experiments.

关键词： hardware service system