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Effect of Central Multiphase Microstructure of Thick Plates on Work Hardening and Crack Propagation

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 325-338页

作者： Lei Hu Liqin zhang Feng Hu Kuan Zheng guohong zhang Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan430081China Department of Applied Physics Wuhan University of Science and TechnologyWuhan430081China Analysis and Testing Center Wuhan University of Science and TechnologyWuhan430081China

The effect of multiphase microstructure in the center segregation zones(CSZ)of high-strength steel thick plates on work hardening characteristics and crack initiation/propagation were studied.Microstructure was correlated with deformation damage behavior by using Taylor factor(TF)gradients,kernel average misorientation(KAM),and geometric necessary dislocation(GND)density.The results show that the segregation leads to a mixed structure of ferrite(soft phase)and martensite/bainite(hard phase)in the center of the thick plate.Compared to the 1/4 thickness(1/4 T)region,grain refinement occurred in the CSZ,with KAM values increasing from 0.24 to 0.49 and a decrease in the proportion of high-angle grain boundaries(>15°)from 77.4 to 51.8%.In the process of deformation,due to the influence of grain refinement and adjacent martensite/bainite,ferrite grains were divided into structural units with different TF values.The higher KAM value and GND density at the interface between soft/hard phases resulted in severe work hardening.In addition,the presence of micron-sized inclusions in the CSZ caused local strain concentration and non-continuous deformation of the matrix,which induced crack initiation.The fracture surface showed a mixed mode of brittle cleavage fracture and ductile fracture.

关键词： Thick plate Center segregation zone Multiphase microstructure Taylor factor Crack propagation

Global dynamics of a Leslie-Gower predator-prey model in open advective environments

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International Journal of Biomathematics 2024年第3期17卷 241-264页

作者： Baifeng zhang guohong zhang Xiaoli Wang School of Mathematics and Statistics Southwest University Chongqing 400715P.R.China

This paper investigates the global dynamics of a reaction-diffusion-advection Leslie-Gower predator-prey model in open advective environments.We find that there exist critical advection rates,intrinsic growth rates,diffusion rates and length of the domain,which classify the global dynamics of the Leslie-Gower predator-prey system into three scenarios:coexistence,persistence of prey only and extinction of both species.The results reveal some significant differences with the classical specialist and generalist predator-prey systems.In particular,it is found that the critical advection rates of prey and predator are independent of each other and the parameters about predation rate have no influence on the dynamics of system.The theoretical results provide some interesting highlights in ecological protection in streams or rivers.

关键词： Leslie Gower predator-prey system advection global dynamics coexistence extinction

Relationships between In SAR Seismic Deformation and Fault Motion Sense,Fault Strike,and Ascending/Descending Modes

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Acta Geologica Sinica(English Edition) 2017年第1期91卷 93-108页

作者： QU Chunyan SHAN Xinjian ZHAO Dezheng zhang guohong SONG Xiaogang Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029

Based on the working principle of satellite radars, the earthquake deformation field measured by interferometric synthetic aperture（InSAR） is the projection of ground displacement associated with the seismogenic fault in the line of sight（LOS） of the satellite. However, LOS projections are complex, and are not only related to the ascending/descending modes and incidence angles of SAR data, but also related to the strike and motion senses of the fault. Even for the same earthquake, the LOS deformation derived from different ascending/descending data can be almost identical in one case, but quite different in another case, which makes the interpretation of InSAR seismic deformation and its comparison with field observations difficult. In this study, we undertook a quantitative analysis of the relationships between LOS observation sensitivity of InSAR and fault strike, fault motion sense, and ascending/descending modes, as well as 3D deformation fields. We studied the features and differences of the LOS deformation fields in different types of earthquakes using ascending/descending modes, with a particularly detailed analysis of the relations for a strikeslip type of earthquake. We also summarized the characteristics of LOS deformation fields of faults with different strikes and optimal observational data modes. Taking the strike-slip Yushu earthquake and the normal Gaize event as examples, we used SAR data of the ascending/descending modes to verify the results of quantitative calculations. These analyses will not only provide a more reasonable interpretation of InSAR seismic deformation fields and but also help understand the differences of seismic deformation fields revealed by data with different observational modes, therefore promoting the application of InSAR technology in seismology.

关键词： InSAR fault earthquake deformation ascending/descending modes

The Surface Rupture Zone and Coseismic Deformation Produced by the Yutian Ms7.3 Earthquake of 21 March 2008,Xinjiang

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Acta Geologica Sinica(English Edition) 2012年第1期86卷 256-265页

作者： SHAN Xinjian QU Chunyan WANG Chisheng zhang Guifang zhang guohong SONG Xiaogang GUO Liming LIU Yunhua State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake Administration Beijing 100029China Institute of Remote Sensing Application Chinese Academy of SciencesBeijing 100101China

On 21 March 2008, a Ms7.3 earthquake occurred at Quickbird, Yutian County, Xinjiang. We attempt to reveal the features of the causative fault of this shock and its coseismic deformation field. Our work is based on analysis and interpretation to high-resolution satellite images as well as differential interferometric synthetic aperture radar （D-InSAR） data from the satellite Envisat SAR, coupled with seismicity, focal mechanism solutions and active tectonics in this region. The result shows that the 40 km-long, nearly NS trending surface rupture zone by this event lies on a range-front alluvial platform in Qira County. It is characterized by distinct linear traces and simple structure with 1-3-m-wide individual seams and maximum 6.5 m width of a collapse fracture. Along the rupture zone many secondary fractures and fault-bounded blocks are seen, exhibiting remarkable extension. The eoseismic deformation affected a large area 100~100 km2. D-InSAR analysis indicates that the interferometric deformation field is dominated by extensional faulting with a small strike-slip component. Along the causative fault, the western wall fell down and the eastern wall, that is the active unit, rose up, both with westerly vergence. Because of the big deformation gradients near the seismogenic fault, no interference fringes are seen on images, and what can be determined is a vertical displacement 70 cm or more between the two fault walls. According to the epicenter and differential occurrence times from the National Earthquake Information Center, China Earthquake Network Center, Harvard and USGS, it is suggested that the seismic fault ruptured from north to south.

关键词： Yuntian Earthquake high resolution image D-InSAR surface rupture zone coseismic deformation field

Ground Surface Ruptures and Near-Fault,Large-Scale Displacements Caused by the Wenchuan Ms8.0 Earthquake Derived from Pixel Offset Tracking on Synthetic Aperture Radar Images

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Acta Geologica Sinica(English Edition) 2012年第2期86卷 510-519页

作者： QU Chunyan SHAN Xinjian LIU Yunhua zhang guohong SONG Xiaogang zhang Guifang GUO Liming HAN Yufei State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China

The 12 May 2008 Wenchuan Ms8.0 earthquake produced surface displacements along the causative fault, the Yingxiu-Beichuan Fault, which are up to several meters near the fault. Because of the large gradient, satellite synthetic aperture radar （SAR） interferometric data are strongly incoherent; the usual SAR interferometry method does not allow such displacements to be measured. In the present study, we employed another approach, the technique based on pixel offset tracking, to solve this problem. The used image data of six tracks are from the Advanced Land Observing Satellite, Phased Array type L-band Synthetic Aperture Radar （ALOS/PALSAR） dataset of Japan. The results show that the entire surface rupture belt is 238 km long, extending almost linearly in a direction of 42°north-east. It is offset left laterally by a north-west-striking fault at Xiaoyudong, and turns at Gaochuan, where the rupture belt shifts toward the south by 5 km, largely keeping the original trend. In terms of the features of the rupture traces, the rupture belt can be divided into five sections and three types. Among them, the Beichuan-Chaping and Hongkou-Yingxiu sections are relatively complex, with large widths and variable traces along the trend. The Pingtong-Nanba and Qingping-Jingtang sections appear uniform, characterized by straight traces and small widths. West of Yingxiu, the rupture traces are not clear. North of the rupture belt, surface displacements are 2.95 m on average, mostly 2-3.5 m, with 7-9 m the maximum near Beichuan. South of the rupture belt, the average displacement is 1.75 m, dominated by 1-2 m, with 3-4 m at a few sites. In the north, the displacements in the radar line of sight are of subsidence, and in the south, they are uplifted, in accordance with a right-slip motion that moves the northern wall of the fault to the east, and the southern wall to the west, respectively. Along the Guanxian-Jiangyou Fault, there is a uplift zone in the radar line of sight, which is 66 km long, 1.5-6 km wide, and has vertical displace

关键词： synthetic aperture radar interferometry incoherent zone surface displacement pixel offset Wenchuan earthquake

Using borehole core analysis to reveal Late Quaternary paleoearthquakes along the Nankou-Sunhe Fault,Beijing

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Science China Earth Sciences 2008年第8期51卷 1154-1168页

作者： zhang ShiMin WANG DanDan LIU XuDong zhang guohong ZHAO JunXiang LUO MingHui REN JunJie WANG Rui zhang YingLi Institute of Crustal Dynamics China Earthquake AdministrationBeijing 100085

The Nankou-Sunhe Fault is a buried active normal fault that traverses the urban area of Beijing.Its seismic risks have caused considerable concerns.This paper studies paleoearthquakes along this fault by analyzing and correlating bore-hole cores obtained from triple-tube coring,incorporating experience acquired from trenching.As a result,a model for identifying earthquake-derived colluvium by sediment-core analysis is proposed.Triple-tube coring technique is useful to collect continuous undis-turbed soil core near the Nankou-Sunhe Fault.By identifying fault-scarp colluviums,determining cumulative displacement,and analysing stratum thickening on the hanging wall,we are able to establish a preliminary paleoearthquake sequence consisting of 13 surface-rupturing events since 60 ka.The seismic history can be divided into three periods based on different recurrence intervals.Between 60 and 40 ka,three earthquakes occurred with recurrence interval of ～10 ka.From 40 to 25 ka,there were six earthquakes with the recurrence interval of about 2.5 ka.In the last 25 ka,four earthquakes have taken place with the recurrence interval varying considerably.The recurrence interval between the last three events is ～5 ka.Smaller recurrence intervals correspond to stages of faster fault slip.The coseismic displacement of a single event is 0.8 to 2.2 m,average 1.4 m,largely equivalent to moment magnitudes 6.7-7.1.This study demonstrates the feasibility of bore-hole drilling in investigating paleoearthquakes along normal faults.It also suggests that closely spaced boreholes with continuous undisturbed cores are essential for reconstructing the complete paleoearthquake sequence.

关键词： Nankou-Sunhe Fault bore-hole surveying triple-tube coring paleoearthquake colluvium

万古霉素骨水泥对感染性骨缺损骨折愈合的影响

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中国当代医药 2024年第6期31卷 49-53页

作者：张国洪贵阳市第四人民医院药剂科贵州贵阳550002

目的探究万古霉素骨水泥对感染性骨缺损患者骨折愈合及炎症因子水平的影响。方法选取2019年1月至2020年12月贵阳市第四人民医院收治的64例感染性骨缺损患者作为研究对象,按照随机数字表法将其分为对照组(32例)与研究组(32例),对照组接... 详细信息

目的探究万古霉素骨水泥对感染性骨缺损患者骨折愈合及炎症因子水平的影响。方法选取2019年1月至2020年12月贵阳市第四人民医院收治的64例感染性骨缺损患者作为研究对象,按照随机数字表法将其分为对照组(32例)与研究组(32例),对照组接受常规清创引流治疗,研究组在对照组基础上采用万古霉素复合型骨水泥植入治疗,比较两组患者骨折愈合优良率、炎症因子改善情况以及术后肢体功能恢复情况。结果研究组患者的骨折愈合优良率、术后关节功能恢复优良率高于对照组,差异有统计学意义(P<0.05)。术后,两组患者白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、红细胞沉降率(ESR)、C反应蛋白(CRP)、白细胞计数(WBC)水平低于本组术前,研究组患者IL-6、TNF-α、ESR、CRP、WBC水平低于对照组,差异有统计学意义(P<0.05)。术后,两组患者平均通过时间(MTT)短于本组术前,血容量(BV)、血流量(BF)水平高于本组术前,研究组患者MTT短于对照组,BV、BF水平高于对照组,差异有统计学意义(P<0.05)。术后,两组患者血管内皮生长因子(VEGF)、转化生长因子β1(TGF-β1)、骨形态发生蛋白2(BMP-2)水平高于本组术前,研究组患者VEGF、TGF-β1、BMP-2水平高于对照组,差异有统计学意义(P<0.05)。结论对感染性骨缺损患者实施万古霉素复合型骨水泥植入治疗可有效降低炎症因子水平,促进患者骨折愈合,改善肢体功能。

关键词：感染性骨缺损骨折万古霉素骨水泥愈合

“非课堂”:一种学生立场的职业教育教学新样态

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中国职业技术教育 2024年第11期 33-40,48页

作者：张国红李双彤王长辉金华市教育教学研究中心职教部浙江省兰溪市职业中等专业学校浙江省兰溪市教育局教研室

针对职业学校中普遍存在的学生学习投入度不足与教学效率偏低的问题,创新性地提出了一种全新的教学样态——“非课堂”。这一概念实现了从传统的时空视角到学生视角的根本转变,旨在为学生营造一种“无课堂感”的自然学习情境,从而激发... 详细信息

针对职业学校中普遍存在的学生学习投入度不足与教学效率偏低的问题,创新性地提出了一种全新的教学样态——“非课堂”。这一概念实现了从传统的时空视角到学生视角的根本转变,旨在为学生营造一种“无课堂感”的自然学习情境,从而激发其学习热情与主动性。在实施策略上,坚持自然性、真实性与情境性的原则,通过教学内容的项目化、教学方法的自然序、教学平台的支持性以及教学空间的场域化等四个维度的整体构建,为非课堂的实施提供有力的支撑。借助现代技术手段使得“非课堂”教学得以多维度协同进化和整体性优化。“非课堂”概念的提出对加速职业教育的自我革新有着重要意义,对整个教育体系改革具有普适性价值。

关键词：职业教育教学非课堂学生立场自然性

湿式离合器摩擦片表面油槽形式对带排扭矩及散热能力的影响

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粉末冶金工业 2024年第3期34卷 54-59页

作者：许成法张坤张登张国洪魏炳忧胡铮杭州前进齿轮箱集团股份有限公司浙江杭州311203 中国科学院力学研究所北京100190 中国北方车辆研究所北京100072

湿式离合器中的摩擦副在带排阶段,由于润滑剂的粘性流体特性,在摩擦副存在相对运动条件下会产生带排扭矩和能量损失,这种现象严重影响使用寿命,减少产品的安全性。针对这一问题,基于Navier-Stokes方程,采用有限元数值模拟仿真的方式,设... 详细信息

湿式离合器中的摩擦副在带排阶段,由于润滑剂的粘性流体特性,在摩擦副存在相对运动条件下会产生带排扭矩和能量损失,这种现象严重影响使用寿命,减少产品的安全性。针对这一问题,基于Navier-Stokes方程,采用有限元数值模拟仿真的方式,设计分析了12种槽型共24个油槽方案探索降低带排扭矩和能量损失的方法 ,结果表明螺旋槽与径向不通槽组合设计冷却效果好,动摩擦因数高,实验结果为摩擦片油槽设计提供了重要的参考依据,具有重要的指导意义。

关键词：湿式离合器摩擦片表面油槽带排扭矩散热能力