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基于正交切削逆识别井下管柱的Johnson-Cook本构模型
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作者 祝效华 周博文 +3 位作者 敬俊 叶文勇 田洋 倪宗清 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期939-950,共12页
在有限元仿真金属切削过程中,本构模型是仿真的基础,目前井下生产管柱J55油管材料的本构模型参数尚不明确,为此,提出一种基于正交切削理论逆识别油管材料Johnson-Cook(J-C)本构模型参数的方法。首先,通过准静态拉伸试验得到油管材料的应... 在有限元仿真金属切削过程中,本构模型是仿真的基础,目前井下生产管柱J55油管材料的本构模型参数尚不明确,为此,提出一种基于正交切削理论逆识别油管材料Johnson-Cook(J-C)本构模型参数的方法。首先,通过准静态拉伸试验得到油管材料的应力-应变曲线,根据曲线拟合确定J55油管的初始屈服强度A、应变硬化系数B和应变硬化因子n;其次,通过正交切削试验获得切削力以及进给力,根据正交切削试验和平行剪切区模型,计算正交切削过程主剪切区中的流动应力、应变、应变率以及切削温度,并将这些参数与计算出的A、B、n代入J-C模型中,得到多组应变率敏感性参数C以及热软化效应参数m,从而确定其约束范围;第三,采用自适应权重粒子群算法在约束范围中搜索出参数C和m的最优值,进而确定J55油管材料本构模型参数;最后,使用逆识别法得出的J-C本构模型进行有限元仿真,将仿真结果与试验结果进行了对比。研究结果表明:与试验相比,有限元仿真的切削力和进给力最大相对误差分别为14.4%和13.64%,有限元仿真模拟温度与实际测量温度的最大相对误差为10.57%,仿真模型和实际切削过程在切屑形态上表现出了一致规律,验证了逆识别方法可行性和本构模型的可靠性。 展开更多
关键词 j55油管 本构模型 逆向识别 正交切削 有限元仿真
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耳穴揿针联合坦索罗辛对输尿管镜碎石术后留置双J管患者USSQ评分及满意度的影响
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作者 谢芳珍 张洁 +3 位作者 方苏平 黄施 李英 沈丹 《新中医》 CAS 2024年第16期171-174,共4页
目的:观察耳穴揿针联合坦索罗辛对输尿管镜碎石术后留置双J管患者输尿管支架相关症状调查问卷(USSQ)评分及满意度的影响。方法:选取74例输尿管镜碎石术后留置双J管患者为观察对象,按随机数字表法分为观察组及对照组各37例。观察组给予... 目的:观察耳穴揿针联合坦索罗辛对输尿管镜碎石术后留置双J管患者输尿管支架相关症状调查问卷(USSQ)评分及满意度的影响。方法:选取74例输尿管镜碎石术后留置双J管患者为观察对象,按随机数字表法分为观察组及对照组各37例。观察组给予常规护理、口服坦索罗联合耳穴揿针治疗,对照组给予常规护理、口服坦索罗联合耳穴压豆治疗。疗程均为6 d,比较2组治疗后USSQ评分及治疗满意度。结果:治疗前,2组USSQ评分比较,差异无统计学意义(P>0.05)。治疗6 d后,2组USSQ评分均较治疗前及治疗3 d下降(P<0.05),并呈明显下降趋势(P<0.05);且观察组相同时间点USSQ评分均低于对照组(P<0.05)。治疗结束后,观察组满意度为97.30%,对照组为83.78%,2组比较,差异有统计学意义(P<0.05)。结论:耳穴揿针联合坦索罗辛可有效改善输尿管镜碎石术后留置双J管患者相关症状和生活质量,提高其治疗满意度。 展开更多
关键词 输尿管镜碎石术 留置双j 耳穴 揿针 输尿管支架相关症状调查问卷
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Resilience4j的熔断策略研究
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作者 郑若鹢 《数字通信世界》 2024年第10期47-49,52,共4页
该文研究了新一代轻量级的容错框架Resilience4j结构功能,结合熔断器工作方式与熔断参数,针对服务的熔断阈值配置问题,提出了一个Resilience4j在微服务平台上的配置方案。根据不同服务的紧迫性,实行不同的配置策略,提升服务性能,有效保... 该文研究了新一代轻量级的容错框架Resilience4j结构功能,结合熔断器工作方式与熔断参数,针对服务的熔断阈值配置问题,提出了一个Resilience4j在微服务平台上的配置方案。根据不同服务的紧迫性,实行不同的配置策略,提升服务性能,有效保护微服务系统。 展开更多
关键词 Resilience4j容错框架 熔断策略 微服务 阈值
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S100A9抑制ALV-J在HD11细胞中增殖
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作者 朱姝桐 朱治坚 +4 位作者 王陈君 郭旺 吴慧显 骆欢 胡序明 《中国动物传染病学报》 CAS 北大核心 2024年第5期22-26,共5页
钙结合蛋白S100A9是损伤相关分子模式蛋白家族的重要成员,在调节细胞的免疫功能和抗病毒免疫中扮演着重要角色。然而,目前尚不清楚S100A9在家禽中是否具有抗病毒功能。本文首先通过定量PCR分析发现ALV-J感染鸡巨噬细胞系HD11后持续性下... 钙结合蛋白S100A9是损伤相关分子模式蛋白家族的重要成员,在调节细胞的免疫功能和抗病毒免疫中扮演着重要角色。然而,目前尚不清楚S100A9在家禽中是否具有抗病毒功能。本文首先通过定量PCR分析发现ALV-J感染鸡巨噬细胞系HD11后持续性下调S100A9基因表达。为了进一步探讨S100A9基因在鸡巨噬细胞中的抗病毒功能及其机制,成功构建了S100A9真核表达载体。最后,通过定量PCR和Western blot检测S100A9过表达对ALV-J复制水平和TLR3信号通路相关基因表达的影响。结果显示:与对照组相比,ALV-J在过表达S100A9的HD11中的增殖水平显著降低。机制上,S100A9显著上调TLR3基因及其下游信号基因(IRF7、IFN-α和IFN-β)在HD11细胞中表达。本研究揭示了鸡S100A9在巨噬细胞中抗病毒功能及其作用机制,为今后探索S100A9基因在ALV-J致病机理中的作用奠定了基础。 展开更多
关键词 s100A9 TLR3 ALV-j 鸡巨噬细胞
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J55钢和80S钢在含硫采出水中的腐蚀电化学行为
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作者 吕雷 马天奇 刘玉博 《科学技术与工程》 北大核心 2024年第29期12516-12523,共8页
油田开发生产中,高含硫+含Cl^(-)环境会引起油管钢严重腐蚀。为了给高含硫+含Cl^(-)环境腐蚀防护方案提供技术依据,通过动电位极化扫描、电化学阻抗测试研究了硫化物含量、Cl^(-)浓度对J55钢和80S钢在高含硫+含Cl^(-)腐蚀环境下电化学... 油田开发生产中,高含硫+含Cl^(-)环境会引起油管钢严重腐蚀。为了给高含硫+含Cl^(-)环境腐蚀防护方案提供技术依据,通过动电位极化扫描、电化学阻抗测试研究了硫化物含量、Cl^(-)浓度对J55钢和80S钢在高含硫+含Cl^(-)腐蚀环境下电化学腐蚀行为的影响。结果表明:随着硫化物含量增大,J55钢和80S钢的腐蚀电位减小,腐蚀倾向性增强,腐蚀电流密度增大,交流阻抗谱的电荷传递电阻减小,腐蚀性增强;随着Cl^(-)浓度增大,J55钢的腐蚀电位增大,腐蚀倾向性减弱,但对80S钢的腐蚀电位(E_(corr))没有呈现规律;对于腐蚀电流密度,J55钢和80S钢的腐蚀电流密度(i_(corr))均随着Cl^(-)浓度增大而增大;80S钢略比J55钢具有较强的抗硫耐蚀性能。 展开更多
关键词 j55钢 80s H_(2)s腐蚀 极化曲线 交流阻抗
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基于NodeJS+VueJS的船舶机务管理系统的设计与实现
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作者 朱嘉涵 何治斌 +2 位作者 陆昊 李佳伟 王鑫鑫 《计算机应用与软件》 北大核心 2024年第11期39-45,77,共8页
船舶的机务管理系统用于有序管理船舶事物,包括监控船上设备、编排设备保养信息、安排船员的工作、记录备件物料的存储等,同时可以处理船端和岸端的往来信息。设计一种新型的B/S架构的机务管理系统Web App,选用近年来流行的前后端分离... 船舶的机务管理系统用于有序管理船舶事物,包括监控船上设备、编排设备保养信息、安排船员的工作、记录备件物料的存储等,同时可以处理船端和岸端的往来信息。设计一种新型的B/S架构的机务管理系统Web App,选用近年来流行的前后端分离开发模式以及非关系型数据存储方案,并借鉴移动端原生应用的交互设计原则,重构机务管理系统的各个模块。通过该方法使得船岸业务更解耦,通信更快捷,减少数据通信量,为船东降低运营成本,并提高数据实时传送准确性。 展开更多
关键词 B/s 前后端分离 非关系型数据库 Nodejs Vuejs WEBAPP
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Criticism on the Critical Approaches in J. Hillis Miller's Fiction and Repetition:Seven English Novels
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作者 汤梦颖 《海外英语》 2014年第23期206-209,共4页
Fiction and Repetition is and will remain a distinguished deconstructionist guide of literary criticism. However, after detailed and systematic research, I also find some shortcomings in this important academic work: ... Fiction and Repetition is and will remain a distinguished deconstructionist guide of literary criticism. However, after detailed and systematic research, I also find some shortcomings in this important academic work: Firstly, written in the metaphysical language, Fiction and Repetition can never succeed in escaping the logocentrism and binary opposition inherent in this language.Secondly, based on Saussure's argument on langue, the monograph's view of indeterminacy of literary work's meaning is theoretically correct but practically inadequate. Last but not the least, Miller's proposal on repetition also has some limitations. By taking into account both the work's merits and demerits, we can gain a more comprehensive outlook on Miller's idea of repetition as well as the deconstruction theory of literary criticism in general. 展开更多
关键词 FICTION and REPETITION j.Hillis millER CRITICIsM d
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IL-6通过激活JAK2/STAT3信号通路增强小鼠肺泡巨噬细胞的吞噬功能 被引量:1
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作者 华梦晴 高培宇 +2 位作者 方芳 苏浩宇 宋传旺 《细胞与分子免疫学杂志》 CAS CSCD 北大核心 2024年第1期13-18,共6页
目的 探讨白细胞介素6(IL-6)对MH-S小鼠肺泡巨噬细胞吞噬功能的影响及其相关机制。方法 脂多糖(LPS)经气道滴入激发构建小鼠急性肺损伤(ALI)模型,ELISA检测支气管肺泡灌洗液(BALF)中IL-6的含量。体外培养MH-S细胞,在信号转导子与转录激... 目的 探讨白细胞介素6(IL-6)对MH-S小鼠肺泡巨噬细胞吞噬功能的影响及其相关机制。方法 脂多糖(LPS)经气道滴入激发构建小鼠急性肺损伤(ALI)模型,ELISA检测支气管肺泡灌洗液(BALF)中IL-6的含量。体外培养MH-S细胞,在信号转导子与转录激活子3 (STAT3)抑制剂Stattic(5μmol/L)存在与否的情况下,再加入IL-6(10 ng/mL~500 ng/mL)刺激6 h,加入荧光微球孵育2 h后,采用流式细胞术检测MH-S细胞吞噬荧光微球情况;Western blot法检测磷酸化的Janus激酶2(p-JAK2)、磷酸化的STAT3(p-STAT3)、肌动蛋白相关蛋白2(Arp2)、纤维型肌动蛋白(F-actin)的表达水平。结果 鼻腔滴入LPS后,小鼠BALF中IL-6含量显著升高。随着IL-6刺激剂量的增加,MH-S细胞吞噬荧光微球的作用增强,Arp2、 F-actin蛋白的表达水平升高。100 ng/mL IL-6刺激MH-S细胞后,p-JAK2和p-STAT3蛋白的表达水平升高。阻断MH-S细胞STAT3信号后,IL-6促进细胞吞噬的效应完全消失,IL-6诱导的Arp2、 F-actin蛋白表达增加被抑制。结论 IL-6通过激活JAK2/STAT3信号通路促进MH-S细胞Arp2、 F-actin蛋白的表达增强吞噬功能。 展开更多
关键词 白细胞介素6(IL-6) MH-s细胞 吞噬功能 janus激酶2(jAK2) 信号转导子与转录激活子3(sTAT3) 肺泡巨噬细胞
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S355J2W+N钢采用不同电弧焊工艺增材修复的对比研究
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作者 安博 陈丽园 +2 位作者 刘宣佑 卢序鑫 陈春焕 《焊接技术》 2024年第8期66-69,共4页
文中通过研究精密脉冲冷焊、TIG、MAG焊接工艺对转向架构架常用材料S355J2W+N钢进行增材修复时的组织与性能的差别,为铁路列车转向架构架进行增材修复提供理论依据。对S355J2W+N钢分别采用精密脉冲冷焊、TIG焊和MAG焊进行焊接,并对比分... 文中通过研究精密脉冲冷焊、TIG、MAG焊接工艺对转向架构架常用材料S355J2W+N钢进行增材修复时的组织与性能的差别,为铁路列车转向架构架进行增材修复提供理论依据。对S355J2W+N钢分别采用精密脉冲冷焊、TIG焊和MAG焊进行焊接,并对比分析了3种不同焊接工艺对S355J2W+N钢的组织和硬度的影响规律。研究结果表明,3种焊接工艺焊接的接头均熔合良好,但精密脉冲冷焊热影响区宽度远远小于常规焊接工艺;3种不同焊接工艺残余应力对比,在热影响区和母材区域,3种焊接工艺在焊趾和焊趾以外5 mm范围内残余应力达到最大;在测试区域内,TIG焊和精密脉冲冷焊应力变化趋势相近,残余应力在焊趾及热影响区范围内达到最大值后持续下降,MAG焊工艺残余应力达到最大值后先减小后增大;TIG焊工艺残余应力大于精密脉冲冷焊。3种不同焊接工艺相比,均能得到合格的焊缝,且精密脉冲冷焊热影响区小,焊缝外观优良,但工作效率低,特别适合补焊量小、对焊后变形严格的应用工况。 展开更多
关键词 增材修复 MAG TIG 精密脉冲冷焊 s355j2W%PLUs%N
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‘Partly'globalized networks and driving mechanism in resource-based state-owned enterprises:A case study of J Group 被引量:1
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作者 Jing Xu Yongchun Yang +1 位作者 Yongjiao Zhang Shan Man 《Geography and Sustainability》 CSCD 2024年第1期77-88,共12页
In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in th... In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in the world market.In China,resource-based state-owned enterprises(SOEs)are tasked with the mission of safeguarding resource security,and their internationalization development ideas and strategic deployment are significantly and fundamentally different from those of other non-state-owned enterprises and large multinational corporations.This study provides ideas for the globalization policies of enterprises in developing countries.We consider J Group in western China as a case and discuss its productive investment and global production network development from 2010 to 2019.We found that J Group was‘Partly'globalized,and there are multiple core nodes with the characteristics of centralized and decentralized coexistence in the production network;in addition,the overall layout centre shifted to Southeast Asia and China;however,its global production was restricted by the enterprise's investment security considerations,support and restrictions of the home country,political security risk of the host country,and sanctions from the West.These findings provide insights for future research:under the wave of anti-globalization and'internal circulation as the main body',resource SOEs should consider the potential risk of investment,especially keeping the middle and downstream industrial chain in China as much as possible. 展开更多
关键词 Global production networks Global value chain Productive investment Resource sOEs j Group ‘Partly'globalized
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Predicting short-term major postoperative complications in intestinal resection for Crohn’s disease:A machine learning-based study 被引量:6
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作者 Fang-Tao Wang Yin Lin +8 位作者 Xiao-Qi Yuan Ren-Yuan Gao Xiao-Cai Wu Wei-Wei Xu Tian-Qi Wu Kai Xia Yi-Ran Jiao Lu Yin Chun-Qiu Chen 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第3期717-730,共14页
BACKGROUND Due to the complexity and numerous comorbidities associated with Crohn’s disease(CD),the incidence of postoperative complications is high,significantly impacting the recovery and prognosis of patients.Cons... BACKGROUND Due to the complexity and numerous comorbidities associated with Crohn’s disease(CD),the incidence of postoperative complications is high,significantly impacting the recovery and prognosis of patients.Consequently,additional stu-dies are required to precisely predict short-term major complications following intestinal resection(IR),aiding surgical decision-making and optimizing patient care.AIM To construct novel models based on machine learning(ML)to predict short-term major postoperative complications in patients with CD following IR.METHODS A retrospective analysis was performed on clinical data derived from a patient cohort that underwent IR for CD from January 2017 to December 2022.The study participants were randomly allocated to either a training cohort or a validation cohort.The logistic regression and random forest(RF)were applied to construct models in the training cohort,with model discrimination evaluated using the area under the curves(AUC).The validation cohort assessed the performance of the constructed models.RESULTS Out of the 259 patients encompassed in the study,5.0%encountered major postoperative complications(Clavien-Dindo≥III)within 30 d following IR for CD.The AUC for the logistic model was 0.916,significantly lower than the AUC of 0.965 for the RF model.The logistic model incorporated a preoperative CD activity index(CDAI)of≥220,a diminished preoperative serum albumin level,conversion to laparotomy surgery,and an extended operation time.A nomogram for the logistic model was plotted.Except for the surgical approach,the other three variables ranked among the top four important variables in the novel ML model.CONCLUSION Both the nomogram and RF exhibited good performance in predicting short-term major postoperative complic-ations in patients with CD,with the RF model showing more superiority.A preoperative CDAI of≥220,a di-minished preoperative serum albumin level,and an extended operation time might be the most crucial variables.The findings of this study can assist clinicians in identifying patients at a higher risk for complications and offering personalized perioperative management to enhance patient outcomes. 展开更多
关键词 Crohn’s disease Postoperative complications NOMOGRAM Random forest Intestinal resection
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PSR J1701-3726脉冲消零现象研究
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作者 蔡沿庆 李清莹 +6 位作者 田杰 李威 党世军 尚伦华 许鑫 支启军 吴家超 《天文学报》 CAS CSCD 北大核心 2024年第5期103-109,共7页
利用Parkes 64 m射电望远镜在中心频率为1369 MHz的观测数据,分析了PSR J1701-3726的脉冲消零现象,发现这颗星的脉冲消零现象存在准周期性,准周期值约为81.25P,其中P为PSR J1701-3726的自旋周期,并计算出脉冲消零比(Nulling Fraction,NF... 利用Parkes 64 m射电望远镜在中心频率为1369 MHz的观测数据,分析了PSR J1701-3726的脉冲消零现象,发现这颗星的脉冲消零现象存在准周期性,准周期值约为81.25P,其中P为PSR J1701-3726的自旋周期,并计算出脉冲消零比(Nulling Fraction,NF)为27%±0.97%.进一步研究单脉冲在脉冲辐射窗口区域的相对能量随时间的变化关系,发现在消零态和爆发态之间存在a、b、c、d共4种不同的切换模式,其中,a模式出现23次,b模式出现6次,c模式出现5次,d模式出现79次,表明状态转换可能存在一定的随机性. 展开更多
关键词 脉冲星:个别:PsR j1701-3726 脉冲消零 方法:数据分析
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GH738高温合金修正J-C本构关系模型和应变补偿Arrhenius本构关系模型的对比
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作者 罗佰乐 鲁世强 +3 位作者 王双见 周世鑫 杨家典 孙清 《材料热处理学报》 CAS CSCD 北大核心 2024年第10期170-182,共13页
在变形温度为980~1100℃,应变速率为0.001~0.1 s-1及高度压下率为60%的条件下对GH738高温合金进行了等温恒应变速率压缩实验,研究了合金的流动应力行为,并分别采用J-C模型和Arrhenius模型构建了合金的流动应力本构关系。结果表明,修正J-... 在变形温度为980~1100℃,应变速率为0.001~0.1 s-1及高度压下率为60%的条件下对GH738高温合金进行了等温恒应变速率压缩实验,研究了合金的流动应力行为,并分别采用J-C模型和Arrhenius模型构建了合金的流动应力本构关系。结果表明,修正J-C模型和应变补偿Arrhenius模型均能较准确表征GH738高温合金的流动应力行为,能较好地预测合金的流动应力,其中修正J-C本构关系模型的相关系数r达0.99172,平均绝对相对误差AARE为7.86%;应变补偿Arrhenius本构关系模型的相关系数r为0.98815,平均绝对相对误差AARE约7.46%。两种本构关系模型具有大体相当的总体预测精度,但对不同变形条件下的预测精度存在一定差异。当应变速率较高、变形温度较低和应变较小时,宜选用修正J-C本构关系模型;反之,宜选用应变补偿Arrhenius本构关系模型。 展开更多
关键词 GH738高温合金 热变形行为 j-C模型 Arrhenius模型
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Morphological disruption and visual tuning alterations in the primary visual cortex in glaucoma(DBA/2J)mice 被引量:1
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作者 Yin Yang Zhaoxi Yang +9 位作者 Maoxia Lv Ang Jia Junjun Li Baitao Liao Jing’an Chen Zhengzheng Wu Yi Shi Yang Xia Dezhong Yao Ke Chen 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第1期220-225,共6页
Glaucoma is a leading cause of irreve rsible blindness wo rldwide,and previous studies have shown that,in addition to affecting the eyes,it also causes abnormalities in the brain.However,it is not yet clear how the pr... Glaucoma is a leading cause of irreve rsible blindness wo rldwide,and previous studies have shown that,in addition to affecting the eyes,it also causes abnormalities in the brain.However,it is not yet clear how the primary visual cortex(V1)is altered in glaucoma.This study used DBA/2J mice as a model for spontaneous secondary glaucoma.The aim of the study was to compare the electrophysiological and histomorphological chara cteristics of neurons in the V1between 9-month-old DBA/2J mice and age-matched C57BL/6J mice.We conducted single-unit recordings in the V1 of light-anesthetized mice to measure the visually induced responses,including single-unit spiking and gamma band oscillations.The morphology of layerⅡ/Ⅲneurons was determined by neuronal nuclear antigen staining and Nissl staining of brain tissue sections.Eighty-seven neurons from eight DBA/2J mice and eighty-one neurons from eight C57BL/6J mice were examined.Compared with the C57BL/6J group,V1 neurons in the DBA/2J group exhibited weaker visual tuning and impaired spatial summation.Moreove r,fewer neuro ns were observed in the V1 of DBA/2J mice compared with C57BL/6J mice.These findings suggest that DBA/2J mice have fewer neurons in the VI compared with C57BL/6J mice,and that these neurons have impaired visual tuning.Our findings provide a better understanding of the pathological changes that occur in V1 neuron function and morphology in the DBA/2J mouse model.This study might offer some innovative perspectives regarding the treatment of glaucoma. 展开更多
关键词 DBA/2j DEGENERATION gamma band oscillations GLAUCOMA primary visual cortex(V1) RETINA single-unit recording tuning curve
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Capsule endoscopy and panendoscopy:A journey to the future of gastrointestinal endoscopy 被引量:1
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作者 Bruno Rosa JoséCotter 《World Journal of Gastroenterology》 SCIE CAS 2024年第10期1270-1279,共10页
In 2000,the small bowel capsule revolutionized the management of patients with small bowel disorders.Currently,the technological development achieved by the new models of double-headed endoscopic capsules,as miniaturi... In 2000,the small bowel capsule revolutionized the management of patients with small bowel disorders.Currently,the technological development achieved by the new models of double-headed endoscopic capsules,as miniaturized devices to evaluate the small bowel and colon[pan-intestinal capsule endoscopy(PCE)],makes this non-invasive procedure a disruptive concept for the management of patients with digestive disorders.This technology is expected to identify which patients will require conventional invasive endoscopic procedures(colonoscopy or balloon-assisted enteroscopy),based on the lesions detected by the capsule,i.e.,those with an indication for biopsies or endoscopic treatment.The use of PCE in patients with inflammatory bowel diseases,namely Crohn’s disease,as well as in patients with iron deficiency anaemia and/or overt gastrointestinal(GI)bleeding,after a non-diagnostic upper endoscopy(esophagogastroduodenoscopy),enables an effective,safe and comfortable way to identify patients with relevant lesions,who should undergo subsequent invasive endoscopic procedures.The recent development of magnetically controlled capsule endoscopy to evaluate the upper GI tract,is a further step towards the possibility of an entirely non-invasive assessment of all the segments of the digestive tract,from mouth-to-anus,meeting the expectations of the early developers of capsule endoscopy. 展开更多
关键词 Non-invasive endoscopy PANENDOsCOPY Magnetically controlled capsule endoscopy Crohn’s disease Digestive bleeding
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Wharton’s jelly mesenchymal stem cells: Future regenerative medicine for clinical applications in mitigation of radiation injury 被引量:1
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作者 Prashasti Sharma Dharmendra Kumar Maurya 《World Journal of Stem Cells》 SCIE 2024年第7期742-759,共18页
Wharton’s jelly mesenchymal stem cells(WJ-MSCs)are gaining significant attention in regenerative medicine for their potential to treat degenerative diseases and mitigate radiation injuries.WJ-MSCs are more naïve... Wharton’s jelly mesenchymal stem cells(WJ-MSCs)are gaining significant attention in regenerative medicine for their potential to treat degenerative diseases and mitigate radiation injuries.WJ-MSCs are more naïve and have a better safety profile,making them suitable for both autologous and allogeneic transplantations.This review highlights the regenerative potential of WJ-MSCs and their clinical applications in mitigating various types of radiation injuries.In this review,we will also describe why WJ-MSCs will become one of the most probable stem cells for future regenerative medicine along with a balanced view on their strengths and weaknesses.Finally,the most updated literature related to both preclinical and clinical usage of WJ-MSCs for their potential application in the regeneration of tissues and organs will also be compiled. 展开更多
关键词 stem cells Wharton’s jelly mesenchymal stem cells RADIOTHERAPY XEROsTOMIA Lung fibrosis
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无镀铜焊丝焊接S355J2W+N耐候钢的焊接接头性能与组织
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作者 陈晓霞 张艳辉 +2 位作者 鲁二敬 石宝岭 侯金柱 《电焊机》 2024年第10期70-76,85,共8页
采用无镀铜焊丝对12 mm厚S355J2W+N耐候钢进行MAG焊接试验,通过拉伸试验、弯曲试验、冲击试验、硬度试验、金相组织和断口组织分析的方法,进行S355J2W+N无镀铜焊丝接头性能的研究。结果表明,无镀铜焊丝焊接的S355J2W+N耐候钢焊接接头具... 采用无镀铜焊丝对12 mm厚S355J2W+N耐候钢进行MAG焊接试验,通过拉伸试验、弯曲试验、冲击试验、硬度试验、金相组织和断口组织分析的方法,进行S355J2W+N无镀铜焊丝接头性能的研究。结果表明,无镀铜焊丝焊接的S355J2W+N耐候钢焊接接头具有良好的拉伸和弯曲性能,抗拉强度和屈服强度均高于母材标准值,断口呈韧性断裂特征。焊缝冲击韧性低于焊接热影响区,且随温度的降低而下降,但均满足母材冲击功不低于27 J(-20℃)的标准要求。焊接接头各区域的硬度符合ISO15614-1标准,均小于HV380,母材区域硬度最低,过热区硬度最高,焊接热影响区的硬度波动最大。金相组织分析表明,焊接接头由焊缝区、过热区、相变重结晶区和不完全相变重结晶区组成,相变重结晶区组织细小均匀,性能最佳。无镀铜焊丝焊接的S355J2W+N耐候钢焊接接头的性能满足生产标准要求。 展开更多
关键词 无镀铜焊丝 s355j2W%PLUs%N耐候钢 力学性能 金相组织 断裂特征
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Study of Type-B QPOs Observed in Black Hole X-Ray Binary Swift J1728.9-3613
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作者 Raj Kumar 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第3期1-9,共9页
We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it dis... We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it disappeared as flux increased,but again appeared at∼7.70 Hz when flux was dramatically decreased.The source was found in the soft intermediate state during these observations.We further studied the energy dependence of the QPO.We found that QPO was observed only for a higher energy range implying that the origin of QPO is possibly due to the corona emitting higher energy photons by the inverse Compton process.The variation of spectral parameters can be explained with the disk truncation model.The fractional rms was found to be monotonically increased with energy.The phase lag spectrum followed the“U-shaped”curve.The rms and phase lag spectrum are modeled and explained with the single-component Comptonization model vkompthdk. 展开更多
关键词 X-rays binaries-accretion-accretion disks-X-rays individual (swift j1728.9-3613)
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Detection of Increasingγ-Ray Emissions from 4FGL J1718.5+4237 with Fermi-LAT
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作者 Jiao Zheng Pengfei Zhang Li Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第8期169-174,共6页
We report a gradual brighteningγ-ray source,4FGL J1718.5+4237,in 0.1-500.0 GeV,which may be associated with a blazar NVSS J171822+423948 with a redshift of~2.7.We analyzed 15.25 yr ofγ-ray data recorded by the Large... We report a gradual brighteningγ-ray source,4FGL J1718.5+4237,in 0.1-500.0 GeV,which may be associated with a blazar NVSS J171822+423948 with a redshift of~2.7.We analyzed 15.25 yr ofγ-ray data recorded by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope and detected significantγ-ray emissions in the direction of the blazar with a test statistic(TS)of~135.Based on timing analysis using a 1 yr time bin,we have observed a gradual brightening inγ-ray emissions from the target.In our analysis,we categorize them into two states:Quiet(TS~0)and Loud(TS~226)states,with the distinction occurring in 2016 August(MJD57602.69).From the Quiet state to the brightest period(the last data point),theγ-ray flux in 0.1-500.0 GeV increased by more than 12-fold from<0.2×10^(-8)photons cm^(-1)s^(-1)to 2.6×10^(-8)photons cm^(-1)s^(-1).Additionally,we studied the spectral properties in detail for the Loud state and the overall data.While no significant variation was detected,both exhibited a spectral indexΓof~2.6.The origin of the brighteningγ-ray emissions from the target is not yet clear.Future long-term multi-wavelength observations and studies will provide insight into the astrophysical mechanisms of the target. 展开更多
关键词 GALAXIEs active-blazars individual(4FGL j1718.5%PLUs%4237)
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超声冲击功率对S355J2G4钢接头组织与性能的影响
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作者 武永利 杨志斌 +2 位作者 车彦龙 康金文 孙亚鹏 《焊接技术》 2024年第8期14-17,共4页
文中基于相同的超声冲击时间采用不同的超声冲击功率对机车车辆用S355J2G4钢焊接接头进行超声冲击处理,系统研究了超声冲击功率对接头微观组织、力学性能和耐磨性能的影响规律。试验结果表明:随超声冲击功率增加,接头表层塑性变形层厚... 文中基于相同的超声冲击时间采用不同的超声冲击功率对机车车辆用S355J2G4钢焊接接头进行超声冲击处理,系统研究了超声冲击功率对接头微观组织、力学性能和耐磨性能的影响规律。试验结果表明:随超声冲击功率增加,接头表层塑性变形层厚度增加且晶粒尺寸减小,但超声冲击功率过大将导致接头表层出现损伤;随超声冲击功率增加,接头表层硬度明显增加,但接头的拉伸性能无明显变化;随超声冲击功率增加,接头疲劳性能呈先增加后减小的趋势;随超声冲击功率增加,接头的耐磨性能明显提升。当超声冲击时间6 min时,超声冲击功率50%处理接头的综合性能最佳。 展开更多
关键词 s355j2G4钢 焊接接头 超声冲击 微观组织 力学性能 耐磨性能
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