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Tempering mechanism of lath martensite induced in IF steel under high pressure

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Journal of Materials Science & Technology 2023年第29期160卷 148-160页

作者： Zuohua Wang haidong sun Xiaogang Guo Peng Wang Ning Liu Dongli Yu Hongwang Zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China

In this paper,low-and high-strength lath martensite(350 and 640 HV)was fabricated in an IF steel via high pressure martensitic transformation.The microstructure and the softening during their tempering from 200°C to 800°C for 1 h were systematically investigated.A carbon-irrelevant tempering process was proposed,exhibiting a three-stage structural evolution pattern depending upon the tempering de-gree(1-(HV-HV FP)/(HV NP-HV FP),where the HV is the instant hardness,HV NP is the non-tempered hard-ness and HV FP is the fully tempered hardness):(1)low tempered(50%),clearing up the remained variant laths via the migration of the triple junctions.Martensite-type microstructure is tailored by low-index lamellar variant boundaries and is thus intrinsically thermally stable,whereas the mobile terminal tips decrease the tempering resistance.The underlying mechanism for such carbon-irrelevant process was discussed and the potential effect on the tempering behavior of carbon-contained martensite was highlighted.

关键词： Tempering mechanism Lath martensite IF steel Terminal tip migration High pressure

{112}<111>Twins or Twinned Variants Induced by Martensitic Transformation?

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Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 133-140页

作者： Zuohua Wang haidong sun Peng Wang Ning Liu Pinwen Zhu Dongli Yu Hongwang Zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Liren College of Yanshan University Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Superhard Materials College of PhysicsJilin UniversityChangchun 130012China

Twinned substructure in lath martensite was induced in the interstitial free(IF)steel via a high pressure thermal cycle(heating up to 1100℃and holding for 30 min,cooling at 10℃/s to room temperature under a pressure of 4 GPa).Experimental observations and theoretical simulation confrm that the twinned substructure has the origin related to the twinned variants rather than the bcc{112}twins,while extra difraction spots were caused by crystal overlapping rather than any extra phase.The diferences in crystallography and electron difraction behavior between twinned variants and{112}twins were discussed in detail.

关键词： Twinned variants {112}twins Martensitic transformation Crystal overlapping Electron difraction

Mechanism and preventive measures of slurry leakage at shield tail brushes under abnormal shutdown condition—A case study

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Underground Space 2023年第1期8卷 144-161页

作者： Fei Ye Haolan Feng Xingbo Han Xiaoming Liang haidong sun Wenjun Zhang Xiaoyong Cao School of Highway Chang’an UniversityXi’an 710064China CCCC First Highway Consultants Co. LtdChina710065 Xi’anChina School of Civil Engineering Tianjin UniversityTianjin 300350China

Based on an underwater shield tunnel project,this study introduces the phenomenon of abnormal shutdown and the measures designed to mitigate problems in construction.On the strength of the analysis of the slurry leakage causes during re-tunneling,the mech-anism of slurry leakage induced by jack retraction was studied,and treatment measures of leakage at shield tail brushes were elaborated upon.The results show that the sudden change of stratum leads to an abnormal shutdown,and a sharp increase in the slurry pressure at the shield cut location leads to the slurry penetrating the gap between the outer wall of the shield shell and the soil,increasing the risk of instantaneous breakdown at shield tail brushes.The radial displacement of the outer wall of the segments caused by retractions of three jacks and a single jack along the circumferential direction distinctly shows three regions and four regions,respectively.The radial shrink-age of the outer wall of the segments at the jack retraction position decreases the tightness between the shield tail brushes and the outer wall of the segments.The expansion of the outer wall of the segments at the surrounding position,especially at the lower position,increases the slurry level to the radial shrinkage position of the segments,which increases the risk of slurry leakage.Furthermore,when the shield machine faces an abnormal shutdown,re-tunneling,and assembly of segments,the jack can be gradually retracted from top to bottom.The slurry leakage degree can be observed when retracting,and the corresponding measures can be taken for timely plugging.According to the leakage degree,it can be determined whether to replace the shield tail brushes to reduce the risk of large-scale leakage accidents.

关键词： Shield tunnel Shield tail brushes Slurry leakage Jack retraction Segment displacement

Construction of nitrogen-doped carbon cladding LiMn_(2)O_(4) film electrode with enhanced stability for electrochemically selective extraction of lithium ions

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Frontiers of Chemical Science and Engineering 2023年第12期17卷 2050-2060页

作者： Jiahui Ren Yongping He haidong sun Rongzi Zhang Juan Li Wenbiao Ma Zhong Liu Jun Li Xiao Du Xiaogang Hao College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China Academia Sinica Qinghai Salt Lake Industry Group Company LimitedGolmud 816000China Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008China

Reducing the dissolution of Mn from LiMn_(2)O_(4)(LMO)and enhancing the stability of film electrodes are critical and challenging for Li+ions selective extraction via electrochemically switched ion exchange technology.In this work,we prepared a nitrogen-doped carbon cladding LMO(C-N@LMO)by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose.The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode.The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42%compared to the LMO film electrode after 10 cycles.The cladding layer not only acted as a protective layer but also functioned as a conductive shell,accelerating the migration rate of Li+ions.The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ions,which was 33%less compared to the pure LMO film electrode.Meanwhile,the C-N@LMO film electrode retained evident selectivity toward Li+ions,and the separation factor was 118.38 for Li+toward Mg2+in simulated brine.Therefore,the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ions from salt lakes.

关键词： LiMn_(2)O_(4) lithium extraction surface coating cyclic stability Mn dissolution

Twinned substructure in lath martensite of water quenched Fe-0.2%C and Fe-0.8%C steels

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Journal of Materials Science & Technology 2020年第14期47卷 126-132页

作者： haidong sun Yuhui Wang Zuohua Wang Ning Liu Yan Peng Xiujuan Zhao Ruiming Ren Hongwang Zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao066004China Liren College of Yanshan University Yanshan UniversityQinhuangdao066004China School of Materials Science&Engineering Dalian Jiaotong UniversityDalian116028China

In the present investigation,twinned substructures within lath martensite of two water quenched steels(0.2 wt.%C and 0.8 wt.%C)were studied.The lath martensite has typical hierarchical packet-block-lath with dislocation substructure.Besides,laths that are misoriented by/70.5°or/60° and bordered by{011}plane,namely twinned laths,are observed,of which the density increases and the scale decreases as more carbons were presented.Such twinned laths have body centered cubic(bcc)crystal structure,belonging to twinned variants following the classical Kurdjumov-Sachs(K-S)orientation relationship with respect to the parent austenite.Unlike bcc{112}twins,twinned variants produce strong double diffraction and in turn the extra diffraction spots that are commonly observed in the martensite in steels with wide range of carbon contents.

关键词： Twinned variant Lath martensite Double electron diffraction Orientation relationship Steels

Effects of Personalized Ultra-early Limb Function Rehabilitation on Neurological Impairment and Satisfaction of Inpatients with Hemiplegia after Ischemic Stroke

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Medicinal Plant 2022年第4期13卷 28-33页

作者： Jing ZENG Yan LI Congfen GONG Xiaodong LIU haidong sun Li ZHANG Hubei University of Medicine Shiyan 442000China Center of Health Administration and Development Studies Hubei University of MedicineShiyan 442000China Department of Neurology Taihe HospitalHubei University of MedicineShiyan 442000China Rehabilitation Forward Department Taihe Hospital of Hubei University of MedicineShiyan 442000China

[Objectives]To investigate the effects of personalized ultra-early limb function rehabilitation on neurological impairment and satisfaction of inpatients with hemiplegia after ischemic stroke.[Methods]From November 2020 to November 2021,66 ischemic stroke patients with hemiplegia in the Neurology Department of a Grade A hospital were randomly divided into experimental group and control group,with 33 cases in each group.The experimental group received personalized ultra-early limb function rehabilitation,and the control group adopted routine rehabilitation nursing.The neurological function defect and nursing service satisfaction of inpatients were compared between the two groups at discharge.[Results]After intervention,the neurological impairment in the experimental group was lighter than that in the control group(P<0.05),and the nursing service satisfaction of the inpatients in the experimental group was higher than that in the control group(P<0.05).[Conclusions]Personalized ultra-early limb function rehabilitation can improve the neurological deficit of inpatients with hemiplegia after ischemic stroke and improve the satisfaction of inpatients.

关键词： Stroke Ultra-early rehabilitation Neurological Function Satisfaction

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苦参碱对缺血性脑卒中大鼠神经炎症的影响

中华老年心脑血管病杂志 2024年第4期26卷 455-459页

作者：孙海东邓敏苏霞潘微武汉市中医医院脑病科 430000 武汉市中医医院检验科

目的探究苦参碱调节高迁移率族蛋白B1(HMGB1)-晚期糖基化终末产物受体(RAGE)信号通路对缺血性脑卒中(IS)大鼠神经炎症的影响。方法将75只SD大鼠随机分为模型组、苦参碱低剂量组(10 mg/kg)、苦参碱高剂量组(20 mg/kg)、苦参碱高剂量+晚... 详细信息

目的探究苦参碱调节高迁移率族蛋白B1(HMGB1)-晚期糖基化终末产物受体(RAGE)信号通路对缺血性脑卒中(IS)大鼠神经炎症的影响。方法将75只SD大鼠随机分为模型组、苦参碱低剂量组(10 mg/kg)、苦参碱高剂量组(20 mg/kg)、苦参碱高剂量+晚期糖基化终末产物(AGE)血清蛋白组(20 mg/kg苦参碱+100 mg/kg AGE血清蛋白)和假手术组,每组15只。采用线栓法构建大鼠大脑中动脉闭塞模型。用Longa评分评估大鼠神经功能缺损;氯化三苯四氮唑染色检测脑梗死情况;苏木精-伊红染色观察海马组织病理变化;酶联免疫吸附测定海马组织白细胞介素(IL)1β、IL-6、肿瘤坏死因子α(TNF-α)水平。Western blot检测海马组织HMGB1、RAGE蛋白表达。结果苦参碱高剂量组Longa评分、脑梗死面积、IL-1β、IL-6、TNF-α、HMGB1和RAGE蛋白表达明显低于模型组和苦参碱低剂量组(P<0.05)。苦参碱高剂量+AGE血清蛋白组Longa评分、脑梗死面积、IL-1β、IL-6、TNF-α、RAGE蛋白表达明显高于苦参碱高剂量组[(2.93±0.30)分vs(1.10±0.12)分,(38.18±4.04)%vs(15.52±1.74)%,(78.57±8.33)pg/ml vs(39.27±4.76)pg/ml,(203.14±24.39)pg/ml vs(92.45±11.23)pg/ml,(243.53±26.81)pg/ml vs(150.49±18.79)pg/ml,0.73±0.07 vs 0.44±0.04,P<0.05]。结论苦参碱可能通过抑制HMGB1-RAGE信号通路减轻IS大鼠的神经炎症。

关键词：苦参碱卒中大鼠,Sprague-Dawley 模型,动物神经炎 HMGB1-RAGE信号通路

老年股骨转子间骨折患者围术期低钠血症发生现状及影响因素分析

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中国实用医刊 2024年第3期51卷 53-56页

作者：田月玲孙海东闫莹莹魏旭洋郑州大学附属郑州中心医院骨科郑州450001

目的探讨老年股骨转子间骨折患者围术期低钠血症的发生现状及影响因素。方法前瞻性队列研究。抽取2021年2月至2023年2月郑州大学附属郑州中心医院骨科接受手术治疗的老年股骨转子间骨折120例患者作为研究对象,围术期监测所有患者血钠浓... 详细信息

目的探讨老年股骨转子间骨折患者围术期低钠血症的发生现状及影响因素。方法前瞻性队列研究。抽取2021年2月至2023年2月郑州大学附属郑州中心医院骨科接受手术治疗的老年股骨转子间骨折120例患者作为研究对象,围术期监测所有患者血钠浓度,术前、术后根据患者的血钠浓度判定其低钠血症发生情况,血钠浓度135 mmol/L,接受手术治疗后发生低钠血症者30例(25.00%,30/120);初步经卡方与独立样本t检验比较发生与未发生低钠血症患者的资料与实验室指标,结果显示,发生组与未发生组术前白蛋白、血尿素氮、血清肌酐水平和氯离子浓度比较差异有统计学意义(P0.05);Logistic回归分结果显示,老年股骨转子间骨折患者术前白蛋白水平、血尿素氮、血清肌酐水平异常过表达是围术期低钠血症发生的影响因素,其中白蛋白异常升高是其保护因素(OR1,P<0.05)。结论老年股骨转子间骨折患者围术期间低钠血症发生风险较高,且多在术后发生,可能与患者术前白蛋白、血尿素氮、血清肌酐水平有关。

关键词：股骨股骨转子间骨折老年患者低钠血症

Apatite Fission Track Thermochronology of Granite from the Xiazhuang Uranium Ore Field,South China:Implications for Exhumation History and Ore Preservation

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 430-440页

作者： sun Yue CHEN Zhengle PAN Jiayong HUO Hailong LI haidong sun Junjie XU Guangchun State Key Laboratory of Nuclear Resources and Environment School of Earth SciencesEast China University of TechnologyNanchang 330013China Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China No.290 Research Institute CNNCShaoguanGuangdong 512029China

Xiazhuang uranium ore field,located in the southern part of the Nanling Metallogenic Belt,is considered one of the largest granite-related U regions in South China.In this paper,we contribute new apatite fission track data and thermal history modeling to constrain the exhumation history and evaluate preservation potential of the Xiazhuang Uranium ore field.Nine Triassic outcrop granite samples collected from different locations of Xiazhuang Uranium ore field yield AFT ages ranging from 43 to 24 Ma with similar mean confined fission track lengths ranging from 11.8±2.0 to 12.9±1.9μm and Dpar values between 1.01 and 1.51μm.The robustness time-temperature reconstructions of samples from the hanging wall of Huangpi fault show that the Xiazhuang Uranium ore field experienced a time of monotonous and slow cooling starting from middle Paleocene to middle Miocene(~60-10 Ma),followed by relatively rapid exhumation in the late Miocene(~10-5 Ma)and nearly thermal stability in the Pliocene-Quaternary(~5-0 Ma).The amount of exhumation after U mineralization since the Middle Paleogene was estimated as~4.3±1.8 km according to the integrated thermal history model.Previous studies indicate that the ore-forming ages of U deposits in the Xiazhuang ore field are mainly before Middle Paleocene and the mineralization depths are more than 4.4±1.2 km.Therefore,the exhumation history since middle Paleocene plays important roles in the preservation of the Xiazhuang Uranium ore field.

关键词： apatite fission track exhumation history ore preservation Xiazhuang Uranium ore field South China