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Chinese Journal of Aeronautics 2016年第4期29卷 1111-1118页

作者： Zhu dong Liu cheng Xu Zhengyang Liu Jia College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

关键词： Cathode design Compressor blade Correction Electric field Electrochemical machining

PAI-1 Derived from Alveolar Type 2 Cells Drives Aging-Associated Pulmonary Fibrosis

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Engineering 2024年第11期42卷 74-87页

作者： Rui Quan Chenhong Shi Yanan Sun chengying Zhang Ran bi Yiran Zhang Xin bi bin Liu Ziheng dong Dekui Jin Yixuan Li Key Laboratory of Functional Dairy Co-Constructed by the Ministry of Education and Beijing MunicipalityBeijing 100083China Department of General Practice The Third Medical Center of the Chinese PLA General HospitalBeijing 100039China Department of Thoracic Surgery The Third Medical Center of the Chinese PLA General HospitalBeijing 100039China Center for Nanomedicine and Department of Anesthesiology Brigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA School of Computer and Information Engineering Luoyang Institute of Science and TechnologyLuoyang 471023China

Pulmonary fibrosis(PF)is a lethal lung disease that predominantly affects older adults;however,whether and how aging triggers fibrosis remains *** pinpoint the predominant initiating factors of PF,we first analyzed single-cell RNA sequencing(scRNA-seq)data from the lung tissues of 45 normal donors and 51 PF patients and found that aging might serve as the primary catalyst for PF *** further investigate the influence of aging on PF formation,we conducted a comprehensive and thorough study employing a natural aging mouse *** found that dynamic alterations in the quantity and types of collagen fibers during aging-induced PF progression,especially in collagenous(Col)I,emerged as the predominant driver of *** then investigated the regulation of Col I synthesis during aging using primary alveolar type 2(AT2)cells and A549 cells line through conditioned media and Transwell cocul-ture,and found that secretions—particularly plasminogen activator inhibitor(PAI)-1—from aged AT2 cells promoted fibrosis and enhanced collagen type I alpha 1(Col1al)production via the transforming growth factor(TGF)-b/small mother against decapentaplegic(Smad)2/3 ***,scRNA-seq and a histological analysis of human lung tissue demonstrated a significant upregulation of SERPINE1(the gene encoding PAI-1)and PAI-1 expression in both aging lung tissue and AT2 cells,which was consistent with our findings from animal experiments,providing additional evidence for the pivotal role of PAI-1 during aging and the development of *** research demonstrates that PAI-1,a crucial factor secreted by aging AT2 cells,exerts a pivotal role in promoting the synthesis of Col1a1 in fibroblasts,subsequently leading to Col I deposition,and in driving the progression of PF by mediating the TGF-b/Smad2/3 *** find-ings offer critical evidence for the involvement of epithelial dysfunction in age-related PF and provides potential novel therapeutic targets for clinical interventio

关键词： Aging Pulmonary fibrosis Alveolar type 2 cells PAI-1

Analysis of Electrical Characteristics of Inter-wire Arc in Cross-Coupling Arc

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 203-211页

作者： Zhenyang Lu Shanwen dong Fan Jiang cheng Li College of Mechanical Engineering and Applied Electronics Technology Ministry of Education Engineering Research Center of Advanced Manufacturing Technology for Automotive Components Beijing University of Technology

As a new composite welding heat source introduced in recent years, the cross-coupling arc uses a non-consumable electrode arc(plasma arc) and a consumable electrode arc(inter-wire arc) in cross-coupling, in which the plasma arc is the main arc and the inter-wire arc is the vice arc, to realize the separate control of the heat input to the workpiece,arc force, and droplet transfer. To reveal the electrical characteristics of the inter-wire arc under the action of the plasma arc, in this study, rotating probes are used to sweep across the plasma arc. When the probes rotate into the plasma arc, a circuit is formed, and the electrical characteristics of the inter-wire arc are indirectly analyzed according to the circuit: the probe centering current and input voltage are used as the physical quantities. The results show that at a certain wire feed rate, the inter-wire arc current increases with increasing input voltage. When the input voltage is low, the wire feed rate has no obvious e ect on the inter-wire arc current. At a higher input voltage, where the wire feed rate is high, the inter-wire arc current decreases. With the increase in the plasma arc current, the inter-wire arc current first increases quickly and then increases slowly, and simultaneously, the striking arc time becomes *** the increase in the interval between the nozzle and the workpiece, the inter-wire arc current increases, but when the arc length increases to a certain limit, the slope of the welding current clearly declines.

关键词： Inter-wire arc Circuit Input voltage Inter-wire arc current

Research and Development Trend of Shape Control for Cold Rolling Strip

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1248-1261页

作者： dong-cheng Wang Hong-Min Liu Jun Liu National Engineering Research Center for Equipment and Technology of Cold Rolling Strip Yanshan University State Key Laboratory of Metastable Materials Science and Technology Yanshan University Anshan Iron and Steel Co.Ltd

Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape con- trol system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll opti- mization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully indus- trial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general,the four expected development trends of shape control for cold roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.

关键词： Cold rolling strip - Shape control Development trend Theory models Shape detectionControl system

Field investigation and numerical simulation on rockfalls in Zhangmu Town, Tibet, China

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Journal of Mountain Science 2022年第3期19卷 740-755页

作者： WANG Zhong-fu LIU Han-dong HE Si-ming bi Dan North China University of Water Resources and Electric Power Zhengzhou 450046China Henan Key Laboratory of Geotechnical and Structure Engineering Zhengzhou 450046China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China China Liaohe Petroleum Engineering co. LTDPanjin124010China

Zhangmu Town in Tibet of China,which lies in the southern piedmont of the median Himalayas,is a small but strategically important port of trade exchange between China and *** rockfall events have occurred in Zhangmu since 1970,resulting in huge economic losses and serious influence on the bilateral *** conducted a detailed field investigation on the high and steep slope in Zhangmu Town,and analyzed the distribution features,stability,failure modes and evolution of dangerous rocks of potential *** we numerically simulated the movement path,velocity and accumulation forms of the rockfall with PFC^(3D) *** results indicated that the dangerous rock belt could be divided into three sections,namely,unstable section,slightly stable section and basically stable *** was estimated that the rock debris and single dangerous rock would be unstable in the case of earthquakes or *** to the terrain constraints,the fallen rocks would scatter near the mouth of the Zhangmu ditch and in the Buqu River through multiple times of rolling,collision-induced diversion and *** reinforcement,the rockfall could cause serious damage to the car parks,gas stations and National Highway 318 along the line from Zhangmu Town to Zhangmu *** on the field survey and numerical simulation,we recommended rockfall removal and interception as the major prevention measures,and protective sheds as auxiliary measure.

关键词： Rockfalls Failure mode Stability analysis Numerical simulation Micro parameters Prevention measures

Preparation and characterization of HMX/EVA/hBNNSs microcomposites with improved thermal stability and reduced sensitivity

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Defence Technology（防务技术） 2021年第2期17卷 650-656页

作者： Yue Yang Xiao-dong Li Yan-tao Sun Jian-an Tian Hui-min Liu bi-dong Wu Jing-yu Wang School of Environment and Safety Engineering North University of ChinaTaiyuan030051ShanxiChina Shanxi Engineering Technology Research Center for Ultrafine Powder North University of ChinaTaiyuan030051ShanxiChina

Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal ***-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).HBNNSs and ethylene-vinyl acetate copolymer(EVA)were introduced to HMX by a solvent-slurry *** comparison,the HMX/EVA and HMX/EVA/graphene(HMX/EVA/G)composites were also prepared by a similar *** morphology,crystal form,surface element distribution,thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively *** showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA,and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites,suggesting superior performance of desensitization of hBNNSs in explosives.

关键词： Energetic materials 2D(two dimensional)materials HBNNSs(hexagonal boron nitride nanosheets) HMX(1,3,5,7-Tetranitro-1,3,5,7-tetrazocane) Thermal stability Mechanical sensitivity

Modulation and enhancement of photonic spin Hall effect with graphene in broadband regions

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Chinese Physics B 2021年第3期30卷 260-265页

作者： Peng dong Gaojun Wang Jie cheng College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Science New Energy Technology Engineering Laboratory of Jiangsu ProvinceNanjing University of Posts and TelecommunicationsNanjing 210023China Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province Nanjing 210023China

The photonic spin Hall effect(SHE)holds great potential applications in manipulating spin-polarized ***,the SHE is generally very weak,and previous studies of amplifying photonic SHE were limited to the incident light in a specific wavelength *** this paper,we propose a four-layered nanostructure of prism-graphene-air-substrate,and the enhanced photonic SHE of reflected light in broadband range of 0 THz–500 THz is investigated *** spin shift can be dynamically modulated by adjusting the thickness of air gap,Fermi energy of graphene,and also the incident *** optimizing the structural parameter of this structure,the giant spin shift(almost equal to its upper limit,half of the incident beam waist)in broadband range is achieved,covering the terahertz,infrared,and visible *** difference is that in the terahertz region,the Brewster angle corresponding to the giant spin shift is larger than that of infrared range and visible *** findings provide us with a convenient and effective way to tune the photonic SHE,and may offer an opportunity for developing new tunable photonic devices in broadband range.

关键词： photonic spin Hall effect graphene spin shift

Novel implementation of homogenization method to predict effective properties of periodic materials

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Acta Mechanica Sinica 2013年第4期29卷 550-556页

作者： Geng-dong cheng Yuan-Wu Cai Liang Xu Dept. of Engineering Mechanics Dalian University of Technology

Representative volume element （RVE） method and asymptotic homogenization （AH） method are two widely used methods in predicting effective properties of pe- riodic materials. This paper develops a novel implementa- tion of the AH method, which has rigorous mathematical foundation of the AH method, and also simplicity as the RVE method. This implementation can be easily realized using commercial software as a black box, and can use all kinds of elements available in commercial software to model unit cells with rather complicated microstructures, so the model may remain a fairly small scale. Several examples were car- fled out to demonstrate the simplicity and effectiveness of the new implementation.

关键词： Effective property ~ Periodic material - Homog-enization ~ RVE method

Prediction of stall inception in multi-stage compressors based on an eigenvalue approach

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Science China(Technological Sciences) 2017年第8期60卷 1132-1143页

作者： cheng FanJie SUN DaKun dong Xu SUN XiaoFeng School of Energy and Power Engineering Beihang University Beijing 100191 China

A stability model for multi-stage compressor is developed on the basis of the eigenvalue *** model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy ***,a linear cascade of blades is modeled by three-dimensional semi-actuator disk theory and the characteristics of steady flow field are also considered in the present *** connection between the analytical solution for stator,rotor and gap can be established by applying mode matching approach,the relevant stability equation can be expressed in the form of matrix,while the compressor system stability can be judged by the imaginary part of the matrix *** capacity of the stall inception model to predict the stall inception point of multi-stage compressor is assessed against the experimental data of National Aeronautics and Space Administration(NASA) two stage *** theoretical results show that this model can predict the stall onset points of a two-stage fan at different operating speeds with a reasonable accuracy.

关键词： multi-stage compressor unsteady flow rotating stall stability model stall inception

Enhancing subspace clustering based on dynamic prediction

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Frontiers of Computer Science 2019年第4期13卷 802-812页

作者： Ratha PECH dong HAO Hong cheng Tao ZHOU Complex Lab University of Electronic Science and Technology of China Chengdu 611731 China big Data Research Center University of Electronic Science and Technology of China Chengdu 611731 China Center for Robotics University of Electronic Science and Technology of China Chengdu 611731 China

In high dimensional data, many dimensions are irrelevant to each other and clusters are usually hidden under noise. As an important extension of the traditional clustering, subspace clustering can be utilized to simultaneously cluster the high dimensional data into several subspaces and associate the low-dimensional subspaces with the corresponding points. In subspace clustering, it is a crucial step to construct an affinity matrix with block-diagonal form, in which the blocks correspond to different clusters. The distance-based methods and the representation-based methods are two major types of approaches for building an informative affinity matrix. In general, it is the difference between the density inside and outside the blocks that determines the efficiency and accuracy of the clustering. In this work, we introduce a well-known approach in statistic physics method, namely link prediction, to enhance subspace clustering by reinforcing the affinity matrix. More importantly, we introduce the idea to combine complex network theory with machine learning. By revealing the hidden links inside each block, we maximize the density of each block along the diagonal, while restrain the remaining non-blocks in the affinity matrix as sparse as possible. Our method has been shown to have a remarkably improved clustering accuracy comparing with the existing methods on well-known datasets.

关键词： subspace clustering link prediction blockdiagonal matrix low-rank representation sparse representation.