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Applications of an Explicit Formula for the Generalized Euler Numbers

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Acta Mathematica Sinica,English Series 2008年第2期24卷 343-352页

作者： guo dong liu Wen Peng ZHANG Department of Mathematics Huizhou University Huizhou 516015 P. R. China Department of Mathematics Northwest University Xi'an 710069 P. R. China

The authors establish an explicit formula for the generalized Euler NumbersE2n^（x）, and obtain some identities and congruences involving the higher＇order Euler numbers, Stirling numbers, the central factorial numbe... 详细信息

关键词： the generalized Euler numbers Stirling numbers the central factorial numbers Dirichlet L-function congruences

Research on conductive-material-filled electrodes for sidewall insulation performance in micro electrochemical machining

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Advances in Manufacturing 2023年第3期11卷 509-522页

作者： guo-dong liu Yu-Lan Zhu Sheng-Gui liu Chao-Jiang Li School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081People's Republic of China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Department of Mechanical EngineeringTsinghua UniversityBeijing 100084People's Republicof China

In micro electrochemical machining(ECM)processes,stray corrosion causes undesired metal dissolution and the deterioration of shape *** a sidewall-insulated electrode is an effective approach to suppressing stray *** sidewall-insulated electrodes are made of metal substrate and non-metallic thin ***,the thin-film insulating materials attached to a metal substrate are susceptible to damage in an electrolytic *** study presents a novel concept of the conductive-material-filled electrode for better sidewallinsulation *** micro-scale quartz tube serves as the insulating *** available conductive fillers including metal wire,molten metals,and silver powder are filled inside the working cathode of the quartz ***,the metal-wire-filled electrode,moltenmetal-filled electrode,and nano-powder-filled electrode are designed and *** the verification results of electrode toughness,material removal rate,and surface topography,the metal-wire-filled electrode and moltenmetal-filled electrode exhibit the same performance as a traditional metal-based electrode and much better *** contrast,the nano-powder-filled electrode is unable to withstand long-term ECM processes because of the loss of cured powder *** ECM experiments,microstructures with steep sidewalls(taper angle<9.7°)were machined using the metal-wire-filled electrode and molten-metal-filled electrode,which could replace the traditional electrode,achieving a longer service life and superior sidewall-insulation performance.

关键词： Electrochemical machining(ECM) Conductive-material-flled electrode Stray corrosion Sidewall insulation Quartz substrate

Evaluation of Slow Light Periodic Signals Considering the Distortion in EDF

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Chinese Physics Letters 2014年第3期31卷 82-85页

作者： WANG WU Chong-Qing WANG Zhi liu guo-dong liu Lan-Lan SUN Zhen-Chao Institute of Optical Information and Key Lab of Luminescence and Optical Information Technology Beijing Jiaotong University Beijing 100044

Based on the fundamental harmonic phase delay, a new definition of fundamental harmonic fractional delay （FHFD） is proposed to evaluate slow light with the consideration of signal distortion, to eliminate the dependence on the choice of the reference point. By solving the rate equation of erbium-doped fiber （EDF）, it is shown that the slow light always accompanies the signal distortion when the periodic signal propagates in EDF, and FHFD depends on the signal distortion, as well as the average input power, the modulation depth and the length of EDF. The results of simulations and experiments indicate that the definition of FHFD is reasonable and effective to evaluate the slow light of periodic signals.

关键词： Signal distortion

Improvement on Conventional Load Distribution Algorithm in Hot Tandem Mills

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Journal of Iron and Steel Research International 2007年第2期14卷 36-41页

作者： LIHai-jun XU Jian-zhong WANG guo-dong liu Xiang-hua State Key Laboratory of Rolling Teehnology and Automation Northeastern University Shenyang 110004 Liaoning China

Load distribution is a key technology in strip hot rolling process, which influences the coil＇s mierostrueture and performance. Currently, Newton-Raphson algorithm is applied to load distribution of hot tandem mills in many hot rolling plants and has some serious defects such as having a strict restriction on initial iterative calculation value and requiring coefficient matrix of nonlinear equations to be nonsingular. To eliminate these defects and improve the online performance of the process control computer, Newton descendent numeric algorithm is introduced to this field to widen the initial value range and a new model named error conversion algorithm is put forth to deal with special conditions when the coefficient matrix is singular. Furthermore, considering the characteristics of load distribution, a condition of strip thickness distribution abnormality and corresponding solutions are provided which ensure that rolling parameters can be calculated normally. Simulation results show that the improved algorithm has overcome the defects of the Newton-Raphson algorithm and is suitable for online application.

关键词： load distribution hot tandem mill process control computer Newton-Raphson algorithm

Effects of Grain Size and Cryogenic Temperature on the Strain Hardening Behavior of VCoNi Medium‑Entropy Alloys

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Acta Metallurgica Sinica(English Letters) 2023年第6期36卷 973-986页

作者： guo‑dong liu Xue‑Mei Luo Ji‑Peng Zou Bin Zhang Guang‑Ping Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationSchool of Materials Science and EngineeringNortheastern UniversityShenyang 110819China

The mechanical behavior of VCoNi medium-entropy alloys with five different grain sizes at three different temperatures was *** VCoNi alloys with different grain sizes exhibit a traditional strength–ductility trade-off at 77 K,194 K and 293 *** the yield strength and the uniform elongation of the VCoNi alloys with similar grain size increase with decreasing the deformation temperature from 293 to 77 *** strain hardening rate recovery characterized by an evident up-turn behavior at stage II is observed in VCoNi alloys with the grain size above 11.1μ*** is found that the extent of the strain hardening rate recovery increases with increasing grain size or decreasing deformation *** may mainly result from the faster increase in the dislocation multiplication rate caused by the decrease in the dislocation mean free path,the decrease in the absorption of dislocations by grain boundaries and the dynamic recovery from the cross-slip with increasing grain size,as well as the suppressed dynamic recovery at cryogenic *** critical grain sizes for the occurrence of the recovery of strain hardening rate are determined to be around 9.5μm,8.3μm and 3μm for alloys deformed at 293 K,194 K and 77 K,*** basic mechanism for the strain hardening behavior of the VCoNi alloys associated with grain size and deformation temperature is analyzed.

关键词： Medium-entropy alloy Strain hardening rate Cryogenic temperature Grain size Slip band refinement

Development of Nb-V-Ti Hot-Rolled High Strength Steel With Fine Ferrite and Precipitation Strengthening

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Journal of Iron and Steel Research International 2009年第4期16卷 72-77页

作者： YI Hai-long DU Lin-xiu WANG guo-dong liu Xiang-hua State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 Liaoning China

A hot-rolled steel with high yield strength of 700 MPa, good elongation of about 20% and low ductile-brittle transition temperature （DBTT） lower than -70℃ has been developed in laboratory. The results show that adopting finishing rolling temperature of around 800℃ is rational, and coiling temperature is between 400 and 500℃ The strength of developed 700 MPa hot-rolled high strength steel is derived from the cumulative contribution of fine grain size, dislocation hardening and precipitation hardening. The fine grain strengthening and precipitation hardening are the dominant factors responsible for such high strength, and good elongation and toughness are predominantly due to fine grain ferrite.

关键词： high strength steel precipitation hardening ductile-brittle transition temperature fine grain strengthening

Bioinformatics-based Identification of Key Pathways and Hub Genes of Traumatic Brain Injury in a Rat Model

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Current Medical Science 2021年第3期41卷 610-617页

作者： Xin-yi CAO Xiao QIAN guo-dong liu Yu-hai WANG Wuxi Clinical College of Anhui Medical University(904th Hospital of the Joint Logistic Support Force of the Chinese People's Liberation Army) Wuxi 214000China

Traumatic brain injury(TBI)is a common injury caused by external forces that lead to damaged brain function or pathological changes in the brain *** explore the molecular mechanism and the hub genes of TBI,we downloaded gene expression profiles of the TBI model of rat and the sham control for the subsequent gene set enrichment analysis,pathway analysis and protein-protein interactions *** results of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated that multiple biological pathways,including immune response,inflammatory response and cellular response to interleukin-1,as well as signaling pathways,such as tumor necrosis factor signaling pathway,chcmokine signaling pathway,cytokine-cytokine receptor interaction,Toll-like receptor signaling pathway and nuclear factor kappa B signaling pathway were implicated in the *** conclusion,this study provides insights into the molecular mechanism of TBI by screening the differentially expressed genes and hub genes that can be used as biomarkers and therapeutic targets.

关键词： traumatic brain injury bioinformatics analysis differentially expressed gene hub gene signal pathway

Numerical Study on Welding Line Behavior of Deep Drawing TWB Process

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Journal of Iron and Steel Research International 2007年第5期14卷 36-38,46页

作者： WANG Li-juan WANG guo-dong liu Xiang-hua WU Ming-tang State Key Laboratory of Rolling Automation and Technology Northeastern University Shenyang 110004 Liaoning China

The FEM technology is used to analyze the welding line movement behavior of deep drawing TWB sheet with different thickness. It is found that high stress fields are concentrated around the welding line and large residual stresses are left. The effect of the welding line movement is like a rigid string and the selected nodes of the thin part near the welding line show the related larger strain.

关键词： welding line behavior deep drawing TWB

Influence of Holding Time After Deformation on Bainite Transformation in Niobium Microalloyed Steel

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Journal of Iron and Steel Research International 2007年第5期14卷 62-65页

作者： YI Hai-long DU Lin-xiu WANG guo-dong liu Xiang-hua State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 Liaoning China

Using Gleeble-1500 system, the influence of holding time on bainite transformation in deformed niobium microalloyed steel during continuous cooling was analyzed, and the carbides in upper bainite were also systematically researched. The results show that the occurrence of the static recrystallization decreases the amount of bainite with an increase in the holding time and the emergence of retained austenite （RA） with the longer holding time. Two types of carbides were observed in upper bainite with regard to their precipitation sites. They either existed between the bainite ferrite laths or co-existed with RA. The formation mechanism of two kinds of carbides was analyzed by combining TEM micrographs with the model.

关键词： niobium microalloyed steel bainite carbide static recrystallization retained austenite