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Mechanical and magnetic hysteresis as indicators of the origin and inception of fatigue damage in steel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第8期11卷 580-586页

作者： Sheng BAO Wei-liang JIN ming-feng huang Institute of Structural Engineering Zhejiang University Hangzhou 310058 China

N2 and N3 are known as the transition points of the three principal stages of fatigue: initial accommodation, accretion of damage and terminal fatigue. Many experiments show that the ratios of N2/Nf and N3/Nf tend to be stable even though the specific N2 and N3 values may fluctuate widely. The primary goal of this research is to study the piezomagnetic field surrounding AISI 1018 steel specimen under repeated loads and to find the ratio values of N2/Nf and N3/Nf by analyzing 11 sets of low-cycle fatigue data. An MTS-810 testing system with a peak capacity of 222 kN was used to obtain the data which consisted of stress, strain, and piezomagnetic field. A computer program was constructed to track the evolution of the piezomagnetic field and re- gression analysis was carried out to determine N2 and N3 values. It was observed that there exists a consistent relationship between N2 and Nf. The apparent invariance of the ratio N2/Nf implies that N2 may be identified as an index of performance in the early loading response of a specimen that forecasts its fatigue life, Nf. It has been demonstrated that measurements of the magnetic and mechanical hysteresis can yield significant insights into the various stages of the development of a fatigue critical microstructure which culminates in complete rupture of the material.

关键词： Piezomagnetic effects. Fatigue damage. Mechanical hvsteresis. Magnetic hysteresis

Design of detector to monitor the Bragg peak location of carbon ions by means of prompt γ-ray measurements with Geant4

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Nuclear Science and Techniques 2018年第4期29卷 83-91页

作者： Yan Fan Guang-ming huang Xiang-ming Sun Zhen Wang Shu-Guang Zou Jun Liu Dong Wang Hui-Li Kang Ping Yang Hua Pei da-ming Sun Zi-Li Li PLAC Key Laboratory of Quark & Lepton Physics (MOE)Department of Physics Science and Technology Central China Normal University Wuhan 430079 Hubei China

Real-time monitoring of the Bragg peak location of carbon ions is urgently required for the quality control of hadron therapy. In this study, we design an annular detector to monitor the Bragg peak location of carbon ions with Geant4 simulation. This 360° surrounding structure has a high detection efficiency for the small-dose situation. The detector consists of a multilayered collimator system and an Na I scintillator for prompt gamma counting. The multilayered collimator includes a lead layer to prevent unwanted gammas and the paraffin and boron carbide layers to moderate and capture fast neutrons. An inclination of the detector further diminishes the background signal caused by neutrons. The detector, with optimized parameters, is applicable to carbon ions of different energies. In addition, the scintillator is replaced by an improved EJ301 organic liquid scintillator to discriminate gammas and neutrons. Inserting thin Fe slices into the liquid scintillator improves the energy deposition efficiency. The Bragg peak location of 200 Me V/u carbon ions can be monitored by prompt gamma detection with the improved liquid scintillator.

关键词： Braggpeak Carbonion Promptc-ray Geant4

离子束抛光对单晶硅表面质量影响的分子动力学模拟研究

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原子与分子物理学报 2025年第6期42卷 113-121页

作者：赵仕燕郭海林黄思玲张旭夏超翔王大森聂凤明裴宁李晓静中国兵器科学研究院宁波分院宁波315103

离子束抛光作为一种超精密加工技术,被应用于材料表面抛光的精抛阶段,而其原子量级的去除效果使得它的加工过程与加工效果难以直接观察,因此为了能够从微观尺度研究离子束抛光的加工效果以及加工参数对材料表面粗糙度与表面损伤的影响,... 详细信息

离子束抛光作为一种超精密加工技术,被应用于材料表面抛光的精抛阶段,而其原子量级的去除效果使得它的加工过程与加工效果难以直接观察,因此为了能够从微观尺度研究离子束抛光的加工效果以及加工参数对材料表面粗糙度与表面损伤的影响,提出使用分子动力学模拟的方法研究离子束抛光过程,通过对氩离子轰击单晶硅的仿真模拟,分析加工参数对单晶硅表面粗糙度与晶格损伤的影响规律,指导实际的加工工艺设计.研究发现,在不同加工角度下,离子剂量对于表面粗糙度的影响规律不同,低角度(0°~40°)低剂量以及高角度(>50°)高剂量的加工有助于达到较低的表面粗糙度;随着加工角度的增加,离子束对晶体表面造成的损伤逐渐减少,当加工角度大于40°时能够大幅度减少晶格损伤.模拟结果显示在实际的离子束抛光过程中,为了得到高质量的表面,应该采取高角度高剂量的加工方式以达到既降低材料表面粗糙度又减小对材料表面晶格产生损伤的目的.

关键词：离子束抛光表面质量分子动力学单晶硅加工角度

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Assessment of Wet Season Precipitation in the Central United States by the Regional Climate Simulation of the WRFG Member in NARCCAP and Its Relationship with Large-Scale Circulation Biases

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Advances in Atmospheric Sciences 2024年第4期41卷 619-638页

作者： Yating ZHAO ming XUE Jing JIANG Xiao-ming HU Anning huang School of Atmospheric Sciences Nanjing UniversityNanjing 210023China Center for Analysis and Prediction of Storms and School of Meteorology The University of OklahomaNorman 73072U.S.A

Assessment of past-climate simulations of regional climate models(RCMs)is important for understanding the reliability of RCMs when used to project future regional ***,we assess the performance and discuss possible causes of biases in a WRF-based RCM with a grid spacing of 50 km,named WRFG,from the North American Regional Climate Change Assessment Program(NARCCAP)in simulating wet season precipitation over the Central United States for a period when observational data are *** RCM reproduces key features of the precipitation distribution characteristics during late spring to early summer,although it tends to underestimate the magnitude of *** dry bias is partially due to the model’s lack of skill in simulating nocturnal precipitation related to the lack of eastward propagating convective systems in the *** in reproducing large-scale circulation and environmental conditions is another contributing *** too weak simulated pressure gradient between the Rocky Mountains and the Gulf of Mexico results in weaker southerly winds in between,leading to a reduction of warm moist air transport from the Gulf to the Central Great *** simulated low-level horizontal convergence fields are less favorable for upward motion than in the NARR and hence,for the development of moist convection as ***,a careful examination of an RCM’s deficiencies and the identification of the source of errors are important when using the RCM to project precipitation changes in future climate scenarios.

关键词： NARCCAP Central United States precipitation low-level jet large-scale environment diurnal variation

Numerical study on roll dynamics of damaged ship in beam waves and calm water

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Journal of Hydrodynamics 2023年第3期35卷 482-497页

作者： Zhi-yun huang Zhi-liang Gao Sang-ming Xu Key Laboratory of High Performance Ship Technology Ministry of Education Wuhan University of TechnologyWuhan 430063China Wuhan University of Technology College of Marine and Energy Power EngineeringWuhan 430063China Union Strong(Beijing)Technology Co. LtdBeijing 100176China

Computational fluid dynamics is used to study the roll dynamics of a damaged ship in beam waves with various steepnesses and in calm *** wave-making method,which combines the velocity-inlet boundary and momentum source with the fifth-order Stokes theory,is employed for wave *** SST k-ωturbulence model with a modification to the turbulent viscosity in Reynolds stress is adopted to prevent the over-production of turbulence in the numerical wave *** lateral drift restrained model with a combined dynamic mesh strategy is utilized to deal with the coupled heave-sway-roll motions of the ***,benchmarking tests are performed,including wave generation and roll response of the damaged ship in regular beam ***,the effects of incident wave steepness on the roll response of the damaged ship are *** different wave steepnesses,the ship roll motion is dominated by the first-order harmonic *** second-order component increases with the increase of wave ***,the roll hydrodynamic coefficients for different parts of the damaged ship are investigated with different rolling *** added moment of inertia for the whole damaged ship is mainly attributed to the external hull composition and changes slightly with the change of roll amplitude and *** added moment of inertia for the compartments could be negative in particular *** damping coefficients of the whole damaged ship and external hull increase with the increase of roll amplitude and frequency,while that of the compartments appears complicated with the change of roll amplitude and frequency.

关键词： damaged ship roll dynamics wave steepness hydrodynamic coefficients computational fluid dynamics(CFD)

A Uniformly Convergent Numerical Method for Singularly Perturbed Nonlinear Eigenvalue Problems

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Communications in Computational Physics 2008年第6期4卷 135-160页

作者： Weizhu Bao ming-huang Chai Department of Mathematics and Center for Computational Science and Engineering National University of Singapore117543Singapore Department of Mathematics National University of Singapore117543Singapore. NUS High School National University of Singapore117543Singapore.

In this paper we propose a uniformly convergent numerical method for discretizing singularly perturbed nonlinear eigenvalue problems under constraints with applications in Bose-Einstein condensation and quantum *** begin with the time-independent Gross-Pitaevskii equation and show how to reformulate it into a singularly perturbed nonlinear eigenvalue problem under a *** asymptotic approximations for the problem are presented to locate the positions and characterize the widths of boundary layers and/or interior layers in the solution.A uniformly convergent numerical method is proposed by using the normalized gradient flow and piecewise uniform mesh techniques based on the asymptotic approximations for the *** numerical results are reported to demonstrate the effectiveness of our numerical method for the ***,the method is applied to compute ground and excited states of Bose-Einstein condensation in the semiclassical regime and some conclusive findings are reported.

关键词： Nonlinear eigenvalue problem Bose-Einstein condensation ground state excited state energy chemical potential piecewise uniform mesh.

Large-vessel thrombosis in intestinal Behet's disease complicated with myelodysplastic syndrome and trisomy 8

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World Journal of Gastroenterology 2012年第10期18卷 1137-1140页

作者： huang-Chi Chen Ying-ming Chiu Division of Critical Care Medicine Department of Internal Medicine Changhua Christian Hospital 500 Changhua Taiwan China Division of Allergy Immunology and Rheumatology Department of Internal Medicine Changhua Christian Hospital 500 Changhua Taiwan China

Behet's disease is characterized by recurrent oral ulcers, genital ulcers, uveitis and skin lesions. Myelodysplastic syndrome (MDS) is characterized by problems due to ineffective hematopoiesis. Several studies have identified a relationship between MDS and Behet's disease, especially intestinal Behet's disease. Trisomy 8 seems to play an important role in these disorders as well. The present case was a 24-year-old woman who had a huge tonsil ulcer with initial symptoms of odynophagia and intermittent fever. We also noted folliculitis on her upper back. Five days later, she began to experience diarrhea and abdominal pain. Abdominal computed tomography and subsequent surgery revealed ileum perforation and enterocolitis with multiple ulcers. Later, she was admitted again for a vulvar suppurative ulcer and suspicious Bartholin's cyst infection. The patient's clinical presentations met the criteria for Behet's disease. Six months after the bowel perforation event, we noted the development of pancytopenia in a routine laboratory examination. All the examinations led to the diagnosis of MDS with trisomy 8. The most unusual finding was that multiple large vessel thrombi developed during follow-up. Previous studies have suggested that trisomy 8 in MDS leads to concurrent intestinal Behet's disease. Moreover, the inflammatory and immune genes related to thrombus formation are overexpressed in cases of MDS with trisomy 8. Trisomy 8 must play a role in thrombosis. Further studies are needed to help clarify the pathophysiology and pathogenesis of these disorders.

关键词： Behcet's disease Myelodysplastic syndrome Trisomy 8 Intestinal ulcers Thrombosis

An Approach to New Water-soluble Oligo(ethylene glycol) Camptothecin Analogues by 1,3-Dipolar Cycloaddition

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Chinese Chemical Letters 2006年第7期17卷 883-886页

作者： Chun Yan XU ming Zhi huang College of Materials Science and Technology Beijing University of Chemical Technology Beijing 100029

Combined with an effective copper-catalyzed triazole-forming reaction, a series of novel camptothecin derivatives were synthesized. Incorporating oligo（ethylene glycol） chains into the derivatives enhanced their wat... 详细信息

关键词： Click chemistry 20(S)-camptothecin water-soluble derivatives.

DYNAMIC DESIGN OF INTERNAL COMBUSTION ENGINE BLOCK STRUCTURE

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Chinese Journal of Mechanical Engineering 1998年第1期11卷 39-43页

作者： Yu, ming huang, Rongqing Lou, Yutao South China Univ of Technology Guangzhou China

Several main steps of internal combustion engine block structure dynamic design,such as model set up,structure dynamic response analysis,optimizing design and vibration and noise control,are discussed for the type of... 详细信息

关键词： Engine block Dynamic design ICE