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Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1089-1097页

作者： Jianjun Xu Hanlin Ding Xin Lin feng Liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core *** HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly *** further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained *** comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ ***,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

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Estimation of Hammerstein nonlinear systems with noises using filtering and recursive approaches for industrial control

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Frontiers of Information Technology & Electronic Engineering 2024年第2期25卷 260-271页

作者： Mingguang ZHANG feng LI Yang YU Qingfeng CAO School of Electrical&Information Engineering Jiangsu University of TechnologyChangzhou213001China College of Electrical Energy and Power EngineeringYangzhou UniversityYangzhou225127China

This paper discusses a strategy for estimating Hammerstein nonlinear systems in the presence of measurement noises for industrial control by applying filtering and recursive *** proposed Hammerstein nonlinear systems are made up of a neural fuzzy network(NFN)and a linear state`-space *** estimation of parameters for Hammerstein systems can be achieved by employing hybrid signals,which consist of step signals and random ***,based on the characteristic that step signals do not excite static nonlinear systems,that is,the intermediate variable of the Hammerstein system is a step signal with different amplitudes from the input,the unknown intermediate variables can be replaced by inputs,solving the problem of unmeasurable intermediate variable *** the presence of step signals,the parameters of the state-space model are estimated using the recursive extended least squares(RELS)***,to effectively deal with the interference of measurement noises,a data filtering technique is introduced,and the filtering-based RELS is formulated for estimating the NFN by employing random ***,according to the structure of the Hammerstein system,the control system is designed by eliminating the nonlinear block so that the generated system is approximately equivalent to a linear system,and it can then be easily controlled by applying a linear *** effectiveness and feasibility of the developed identification and control strategy are demonstrated using two industrial simulation cases.

关键词： Hammerstein nonlinear systems Neural fuzzy network Data filtering Hybrid signals Industrial control

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A new method for identifying flow pattern of spouted fluidized bed by coupling Hilbert-Huang transform characteristics of differential pressure signals in different zones

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Particuology 2024年第6期89卷 67-78页

作者： Yongzhi Mei Yang Wang Lihui Zhang feng Duan School of Energy and Environment Anhui University of TechnologyMaanshan243002China Wuhu Technology and Innovation Research Institute Wuhu241000China Wuhu Cigarette Factory of China Tobacco Anhui Industrial Co. Ldt.Wuhu241002China

On a cold spouted fluidized bed,this study compares the characteristic differences in intrinsic mode function(IMF)energy and Hilbert–Huang spectrum between the spout zone and annulus zone under different combinations of spouted gas and fluidized gas flow rates for five typical flow *** energy distribution characteristics under different flow patterns are also *** Hilbert–Huang spectrum and IMF energy of pressure difference signals exhibit distinct variations in different zones as the flow pattern ***,there exists a correlation between the energy in the middle-frequency range and the flow *** the K-means algorithm,the middle-frequency range energy of IMFs in the spout zone and annulus zone is subjected to clustering analysis,leading to the identification of partition boundaries for each flow *** on this,a flow pattern identification method of spouted fluidized bed coupled with middle-frequency range energy in spout zone and annulus zone is proposed,which has very high identification accuracy.

关键词： Spouted fluidized bed Flow pattern Zoning signal Flow pattern transition Hilbert-Huang transform

Classification and spectrum optimization method of grease based on infrared spectrum

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Friction 2024年第6期12卷 1154-1164页

作者： Xin feng Yanqiu XIA Peiyuan XIE Xiaohe LI School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR *** Kohonen neural network algorithm was used to identify the type of the lubricating *** results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum,and complete the feature selection and dimensionality reduction of the high-dimensional spectral *** 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands,which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these *** model achieved recognition accuracy of 100.00%,96.08%,94.87%,100.00%,and 87.50%for polyurea grease,calcium sulfonate composite grease,aluminum(Al)-based grease,bentonite grease,and lithium-based grease,*** on the different IR absorption spectrum bands produced by each kind of lubricating grease,the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the *** paper demonstrates fast recognition speed and high accuracy,proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.

关键词： grease infrared(IR)spectroscopy layered Kohonen network species recognition spectrum band optimization

Securing multi-chain consensus against diverse miner behavior attacks in blockchain networks

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Frontiers of Information Technology & Electronic Engineering 2024年第4期25卷 540-554页

作者： Wenbo ZHANG Tao WANG Chaoyang ZHANG Jingyu feng School of Cyberspace Security Xi’an University of Posts and TelecommunicationsXi’an 710121China Postal Savings Bank of China Xi’an 710000China

As cross-chain technologies enable interactions among different blockchains(hereinafter“chains”),multi-chain consensus is becoming increasingly important in blockchain ***,more attention has been paid to single-chain consensus ***-chain consensus schemes with trusted miner participation have not been considered,thus offering opportunities for malicious users to launch diverse miner behavior(DMB)attacks on different *** attackers can be friendly in the consensus process on some chains,called mask chains,to enhance their trust value,while on others,called kill chains,they engage in destructive behaviors on the *** this paper,we propose a multi-chain consensus scheme named Proof-of-DiscTrust(PoDT)to defend against DMB *** idea of distinctive trust(DiscTrust)is introduced to evaluate the trust value of each user across different *** trustworthiness of a user is split into local and global trust values.A dynamic behavior prediction scheme is designed to enforce DiscTrust to prevent an intensive DMB attacker from maintaining strong trust by alternately creating true or false blocks on the kill *** trusted miner selection algorithms for multi-chain environments can be implemented to select network miners,chain miners,and chain miner leaders,*** results show that PoDT is secure against DMB attacks and more effective than traditional consensus schemes in multi-chain environments.

关键词： Blockchain Cross-chain Trust mechanism Multi-chain consensus

Stimulating Start-up Investment Through Government-Sponsored Venture Capital: Theory and Chinese Evidence

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Journal of Systems Science & Complexity 2024年第5期37卷 2021-2053页

作者： NI Xuanming ZHENG Tiantian GAO feng ZHAO Huimin School of Software and Microelectronics Peking University School of Economics and Management Tsinghua University School of Business Sun Yat-sen University

Government-sponsored venture capital(GVC) has been used to support financially constrained start-ups as an important policy tool in China. Typically, to motivate the social capital to invest in start-ups, GVC provides subsidies for them to bridge the funding gap in the early-stage venture capital market. However, the effect and mechanism of GVC affecting social capital investment have not been clearly studied. In this paper, the authors not only develop a game model to analyze this issue in theory, but conduct an empirical study by analyzing the 14741 records matched by propensity score matching(PSM) of Chinese venture capital market data from 2011 to 2021. The proposed findings are as the follows. Firstly, the subsidies offered by GVC will simultaneously increase the returns and risks of investments in start-ups of social capital with more volatile incentive effect of GVC. The incentive effect of GVC is only effective when the returns resulting from the subsidies outweigh the risks they introduce. In the context of the Chinese venture capital market, the incentive effect of GVC is effective. Secondly, the incentive effect of GVC is more pronounced in high-tech industries, which can be attributed to the signaling effect facilitated by GVC. In this context, the subsidy mainly helps social capital to bear the costs associated with screening potential investments. Thirdly, the incentive effect of GVC is more significant in underdeveloped venture capital markets, which can be explained by the “virtuous cycle” effect, in which GVC plays a pioneering role in establishing a more robust early-stage market trading system. By examining these three points, this study contributes to a better understanding of how GVC can effectively guide social capital investment, especially in the Chinese landscape.

关键词： Government-sponsored venture capital fund incentive effect social capital subsidy venture capital

Galectin 2 regulates JAK/STAT3 signaling activity to modulate oral squamous cell carcinoma proliferation and migration in vitro

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BIOCELL 2024年第5期48卷 793-801页

作者： XINRU feng LI XIAO Medical School University of Electronic Science and Technology of ChinaChengdu610072China Department of Stomatology Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengdu610072China

Background:Galectin 2(LGALS2)is a protein previously reported to serve as a mediator of disease progression in a range of *** function of LGALS2 in oral squamous cell carcinoma(OSCC),however,has yet to be explored,prompting the present study to address this literature ***:Overall,144 paired malignant tumor tissues and paracancerous OSCC patient samples were harvested and the LGALS2 expression levels were examined through qPCR and western *** LGALS2 coding sequence was introduced into the pcDNA3.0 vector,to enable the overexpression of this gene,while an LGALS2-specific shRNA and corresponding controls were also *** functionality of LGALS2 as a regulator of the ability of OSCC cells to grow and undergo apoptotic death in vitro was assessed through EdU uptake and CCK-8 assays,and flow cytometer,whereas a Transwell system was used to assess migratory activity and *** agonist of the Janus Kinase 2(JAK2)/Signal Transducer and Activator of Transcription 3(STAT3)pathway was also used to assess the role of this pathway in the context of LGALS2 ***:Here,we found that lower LGALS2 protein and mRNA expression were evident in OSCC tumor tissue samples,and these expression levels were associated with clinicopathological characteristics and patient survival *** LGALS2 enhanced proliferation in OSCC cells while rendering these cells better able to resist *** opposite was instead observed after LGALS2 was ***,the ability of LGALS2 to suppress the progression of OSCC was related to its ability to activate the JAK/STAT3 signaling ***:Those results suggest a role for LGALS2 as a suppressor of OSCC progression through its ability to modulate JAK/STAT3 signaling,supporting the potential utility of LGALS2 as a target for efforts aimed at treating OSCC patients.

关键词： LGALS2 Oral squamous cell carcinoma(OSCC) Janus Kinase 2/Signal Transducer and Activator of Transcription 3(JAK2-STAT3) Progression

Evaluation of transmission risk of respiratory particles under different ventilation strategies in an elevator

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Building Simulation 2024年第5期17卷 771-784页

作者： Liangyu Zhu Xian Li Bujin feng Fan Liu School of Civil Engineering and Architecture Linyi UniversityLinyi276000China College of Agriculture Shandong Agricultural UniversityTaian271018China School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China

People in elevators are at risk of respiratory infection because the elevator cabin is crowded and has poor *** exhaled particles may be inhaled by the susceptible person,deposited on the surface and suspended in the elevator,which can result in direct and indirect ***,whether the air vent designs adopted in the elevator can effectively reduce the transmission risk of respiratory particles remains *** this study,the dispersion of particles under four common ventilation strategies used in the commercial elevator was investigated by proven computational fluid dynamics(CFD)*** flow field was simulated with the RNG κ-ξ turbulence model and the Lagrangian method was adopted to track particle *** effects of air vent layout and airflow rate on particle transmission were *** found that more than 50% of exhaled particles(average value)were suspended in the cabin and difficult to discharge under the investigated ventilation *** deposited fraction of particles on the susceptible person reached up to 39.14% for infiltration ventilation,which led to a high risk of contact *** the ventilation rate could not significantly reduce the inhalation proportion of particles due to the poor airflow distribution inside the elevator.A more proper ventilation strategy should be explored for the elevator to control transmission risk.

关键词： particle dispersion transmission risk elevator ventilation strategy computational fluid dynamics(CFD)

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基于双级互补滤波的姿态测量算法设计

传感技术学报 2019年第12期32卷 1824-1829页

作者：高宁李杰冯凯强许廷金高诗尧李炳臻中北大学电子测试技术重点实验室

陀螺仪的漂移、载体的线性加速度和磁场的干扰是影响MARG传感器姿态测量精度的主要原因。针对传统姿态测量算法在磁干扰环境下由于航向角误差导致水平角测量精度降低以及载体线性加速度影响水平角精度的问题,提出了一种基于四元数的双... 详细信息

陀螺仪的漂移、载体的线性加速度和磁场的干扰是影响MARG传感器姿态测量精度的主要原因。针对传统姿态测量算法在磁干扰环境下由于航向角误差导致水平角测量精度降低以及载体线性加速度影响水平角精度的问题,提出了一种基于四元数的双级互补滤波姿态融合算法。该算法利用加速度计和磁力计测量数据分别对估计四元数进行补偿修正,避免了磁干扰环境下航向角误差对水平姿态测量的影响。同时引入线性加速度误差和磁干扰误差自适应补偿方案,以降低线性加速度与磁干扰的影响。为了验证算法的有效性,进行了静态与动态实验,实验结果表明该姿态测量算法能显著提高姿态测量精度和抗干扰能力。与传统的Mahony算法相比,俯仰/滚动角的测量精度完全不受磁干扰的影响,性能得到了明显的提升。

关键词：姿态测量 MARG 四元数磁干扰互补滤波

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