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不同焊速下Ti6Al4V激光焊接头显微硬度、组织和晶粒取向联系 被引量:13
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作者 徐甄真 董志强 +2 位作者 余钊辉 王文科 张建勋 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1277-1289,共13页
为了提高对Ti6Al4V钛合金激光焊接接头中各微区的显微组织和微区力学性能的理解,对不同焊接速度下接头中显微硬度曲线的分布趋势及其与显微组织和取向差之间的关系进行研究。从焊缝中心到母材,熔合线附近的显微硬度值(Hm)最高。在同一... 为了提高对Ti6Al4V钛合金激光焊接接头中各微区的显微组织和微区力学性能的理解,对不同焊接速度下接头中显微硬度曲线的分布趋势及其与显微组织和取向差之间的关系进行研究。从焊缝中心到母材,熔合线附近的显微硬度值(Hm)最高。在同一接头中,Hm随着焊缝宽度增加而增加;在不同接头中,Hm随着不均匀度增加而增加。从焊缝到母材,随着马氏体含量减少和初始α相含量增多,显微硬度逐渐降低。当显微组织主要由马氏体组成时,在较宽的焊缝中或在不同焊速接头的焊缝中心,显微硬度随着冷却速率、马氏体大小和马氏体的晶界取向差而变化;焊缝较窄时,冷却速率等引起的显微硬度的差异较小。 展开更多
关键词 显微硬度 显微组织 晶界角 不均匀性 焊接速度
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Treadmill training improves neurological deficits and suppresses neuronal apoptosis in cerebral ischemic stroke rats 被引量:4
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作者 Li-Mei Cao zhi-qiang dong +1 位作者 Qiang Li Xu Chen 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第8期1387-1393,共7页
RehabilNation training is believed to be beneficial to patients with stroke, but its molecular mechanism is still unclear. Rat models of cerebral ischemic stroke were established by middle cerebral artery occlusion/re... RehabilNation training is believed to be beneficial to patients with stroke, but its molecular mechanism is still unclear. Rat models of cerebral ischemic stroke were established by middle cerebral artery occlusion/reperfusion, and then received treadmill training of different intens让ies, twice a day for 30 minutes for 1 week. Low-intensity training was conducted at 5 m/min, with a 10-minute running, 10-minute rest, and 10-minute running cycle. In the moderate-intensity training, the intensity gradually increased from 5 m/min to 10 m/min in 5 minutes, with the same rest cycle as above. In high-intensity training, the intensity gradually increased from 5 m/min to 25 m/min in 5 minutes, with the same rest cycle as above. The Bederson scale was used to evaluate the improvement of motor function. Infarct volume was detected using 2,3,5-triphenyltetrazolium chloride staining. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining was applied to detect the apoptosis of nerve cells in brain tissue. Western blot assay was employed to analyze the activation of cyclic adenosine monophosphate (cAMP)/protein kinase A and Akt/glycogen synthase kinase-3卩 signaling pathways in rat brain tissue. All training intensities reduced the neurological deficit score, infarct volume, and apoptosis in nerve cells in brain tissue of stroke rats. Training intensities activated the cAMP/protein kinase A and Akt/glycogen synthase kinase-3 beta signaling pathways. This activation was more obvious with higher training intensities. These changes were reversed by intracerebroventricular injection of protein kinase A inhibitor Rp-cAMP. Our findings indicate that the neuroprotective effect of rehabilitation training is achieved via activation of the cAMP/ protein kinase A and Akt/glycogen synthase kinase-3 beta signaling pathways. This study was approved by the Ethics Committee of Animal Experimentation in Shanghai No. 8 Peoples Hospital, China. 展开更多
关键词 nerve REGENERATION ischemic stroke TREADMILL training neuronal DEFICIT apoptosis cyclic adenosine MONOPHOSPHATE protein kinase A GLYCOGEN synthase kinase-3^ NEUROPROTECTIVE effect neural REGENERATION
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Y-shaped shunt for the treatment of Dandy-Walker malformation combined with giant arachnoid cysts:A case report 被引量:1
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作者 zhi-qiang dong Yan-Fei Jia +5 位作者 Zhen-Shan Gao Qiao Li Liang Niu Qiang Yang Ya-Wen Pan Qiang Li 《World Journal of Clinical Cases》 SCIE 2022年第7期2275-2280,共6页
BACKGROUND Dandy-Walker malformation(DWM)was first reported in 1914.In this case report,a pediatric case was complicated with giant and isolated arachnoid cysts in the right cerebellar hemisphere along with the typica... BACKGROUND Dandy-Walker malformation(DWM)was first reported in 1914.In this case report,a pediatric case was complicated with giant and isolated arachnoid cysts in the right cerebellar hemisphere along with the typical DWM.CASE SUMMARY The patient was at 20 mo old boy,with the complaint of staggering for more than 2 mo.He was admitted to the hospital due to high intracranial pressure and staggering.At admission,the patient had typical manifestations of high intracranial pressure,including vomiting,poor appetite and feeding difficulty.Physical examination revealed increased head circumference,closed anterior fontanelle,unstable standing,staggering,leaning right while walking and ataxia.After admission,he was diagnosed with DWM accompanied by giant isolated arachnoid cysts in the posterior fossa.He underwent Y-shaped three-way valve repair for treating differential pressure between the supratentorial hydrocephalus and the subtentorial arachnoid cysts at once.The child recovered well after the surgery.CONCLUSION In this case,supratentorial and subtentorial shunts were placed,which solved the problem of differential pressure between the supratentorial and subtentorial parts simultaneously.This provides useful information regarding treatment exploration in this rare disease. 展开更多
关键词 Arachnoid cyst Cysto-peritoneal shunt Dandy-Walker malformation Ventriculoperitoneal shunt Case report
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Geomechanical risk and mechanism analysis of CO_(2) sequestration in unconventional coal seams and shale gas reservoirs 被引量:2
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作者 Nian-jie Kuang Jun-ping Zhou +3 位作者 Xue-fu Xian Cheng-peng Zhang Kang Yang zhi-qiang dong 《Rock Mechanics Bulletin》 2023年第4期38-55,共18页
With global greenhouse gas emissions hitting record highs in 2021,CO_(2) geological sequestration(CGS)is the most realistic and feasible technology to ensure large-scale carbon reduction to achieve global carbon cappi... With global greenhouse gas emissions hitting record highs in 2021,CO_(2) geological sequestration(CGS)is the most realistic and feasible technology to ensure large-scale carbon reduction to achieve global carbon capping and carbon neutrality goals.Both coalbed methane and shale gas have the characteristics of self-generation and selfstorage,which is considered to be a valuable target reservoir for geological sequestration of CO_(2).After a high volume of CO_(2) is injected into unconventional coal seams and shale gas reservoirs,many geomechanical issues may be induced,resulting in leakage.Therefore,it is crucial to evaluate the geomechanical risks of CO_(2) geological sequestration.In this article,global CO_(2) emissions and geological resources available for sequestration are teased out.The effects of coupled CO_(2)-water-rock-driven geomechanical,geophysical,and geochemical interactions on the evolution of rock physical properties and pore characteristics,as well as caprock sealing,are discussed.The caprock failure and its inducing mechanism are analyzed,and the criteria for predicting the occurrence of risk are summarized,which is necessary for pressure management and risk prevention.To serve as a benchmark for CO_(2) sequestration in unconventional coal seams and shale gas reservoirs. 展开更多
关键词 CO_(2)sequestration Adsorption effect Coupling effect Unconventional reservoir Caprock failure Leakage path
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