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Microstructure and toughness of thick-gauge pipeline steel joint via double-sided friction stir welding combined with preheating

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 724-733页

作者： Guangming Xie Ruihai Duan Yuqian Wang zong’an luo Guodong Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Fusion welding easily causes microstructural coarsening in the heat-affected zone(HAZ) of a thick-gauge pipeline steel joint. This is most significant in the inter-critically coarse-grained HAZ(ICCGHAZ), which considerably deteriorates the toughness of the joint. In the present work, 11-mm thick pipeline steel was joined by preheating and double-sided friction stir welding(FSW). A comparative study on the microstructure and toughness in the ICCGHAZs for FSW and gas metal arc welding(GMAW) was performed. The toughness in the ICCGHAZ for FSW was improved significantly than that in the ICCGHAZ for GMAW. Generally, the nugget zone(NZ) has a coarse microstructure in the FSW steel joint formed at the highest peak temperature. However, in the current study, the microstructure in the one-pass NZ was remarkably refined owing to the static recrystallization of ferrite. An excellent toughness was achieved in the NZ of the pipeline steel joint that employed FSW.

关键词： pipeline steel thick-gauge plate friction stir welding microstructure toughness

Preliminary exploration of animal models of congenital choledochal cysts

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World Journal of Gastroenterology 2024年第10期30卷 1420-1430页

作者： Shu-Hao Zhang Yue-Bin Zhang Duo-Te Cai Tao Pan Ken Chen Yi Jin Wen-Juan luo zong-Wei Huang Qing-Jiang Chen Zhi-Gang Gao Department of General Surgery Children’s HospitalZhejiang University School of MedicineHangzhou 310000Zhejiang ProvinceChina

BACKGROUND Various animal models have been used to explore the pathogenesis of choledochal cysts(CCs),but with little convincing results.Current surgical techniques can achieve satisfactory outcomes for treatment of CCs.Consequently,recent studies have focused more on clinical issues rather than basic research.Therefore,we need appropriate animal models to further basic research.AIM To establish an appropriate animal model that may contribute to the investigation of the pathogenesis of CCs.METHODS Eighty-four specific pathogen-free female Sprague-Dawley rats were randomly allocated to a surgical group,sham surgical group,or control group.A rat model of CC was established by partial ligation of the bile duct.The reliability of the model was confirmed by measurements of serum biochemical indices,morpho-logy of common bile ducts of the rats as well as molecular biology experiments in rat and human tissues.RESULTS Dilation classified as mild(diameter,≥1 mm to<3 mm),moderate(≥3 mm to<10 mm),and severe(≥10 mm)was observed in 17,17,and 2 rats in the surgical group,respectively,while no dilation was observed in the control and sham surgical groups.Serum levels of alanine aminotransferase,aspartate aminotrans-ferase,total bilirubin,direct bilirubin,and total bile acids were significantly elevated in the surgical group as compared to the control group 7 d after surgery,while direct bilirubin,total bilirubin,and gamma-glutamyltransferase were further increased 14 d after surgery.Most of the biochemical indices gradually decreased to normal ranges 28 d after surgery.The protein expression trend of signal transducer and activator of transcription 3 in rat model was consistent with the human CC tissues.CONCLUSION The model of partial ligation of the bile duct of juvenile rats could morphologically simulate the cystic or fusiform CC,which may contribute to investigating the pathogenesis of CC.

关键词： Choledochal cyst Animal model Partial ligation Cystic and fusiform dilation Juvenile rats

县域养老设施发展水平的空间不匹配研究——以江苏省为例

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人文地理 2024年第1期39卷 40-47,112页

作者：顾宗倪罗小龙南京大学建筑与城市规划学院南京210093

本文基于养老设施的数量、容量、多样性、医疗服务要素,构建养老设施发展水平指标,研究江苏省95个区县养老资源空间分布特征。通过运用基尼系数和空间自相关分析,研究养老设施发展水平与人口老龄化的匹配性,并运用空间回归模型探究影响... 详细信息

本文基于养老设施的数量、容量、多样性、医疗服务要素,构建养老设施发展水平指标,研究江苏省95个区县养老资源空间分布特征。通过运用基尼系数和空间自相关分析,研究养老设施发展水平与人口老龄化的匹配性,并运用空间回归模型探究影响因素。研究发现:(1)高行政级别和经济发达区县的养老设施发展水平具有一定优势。(2)区县的养老设施发展水平与人口老龄化的空间失配地区呈现组团集聚的特点。(3)卫生机构床位数、绿地公园面积、水域面积等健康因素对养老设施发展水平具有显著的促进作用。医疗资源比自然环境资源对于养老设施发展水平更具有提升作用,养老设施的空间布局更加强调与老年人的健康需求相结合。本研究对养老设施布局优化具有积极意义。

关键词：养老设施空间分异特征空间效应养老设施发展水平健康因素

Interfacial microstructure and mechanical properties of stainless steel clad plate prepared by vacuum hot rolling

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Journal of Iron and Steel Research(International) 2018年第7期25卷 732-738页

作者： Jun Jiang Hua Ding zong-an luo Guang-ming Xie School of Materials and Metallurgy Northeastern University Shenyang 110819 Liaoning China Shenyang Aircraft Corporation Shenyang 110034 Liaoning China State Key Laboratory of Roiling and Automation Northeastern University Shenyang 110819 Liaoning China

A stainless steel clad plate composed of stainless steel and carbon steel was prepared by vacuum hot rolling process, and its microstructure, especially the bonding interface, was evaluated using an optical microscope, a scanning electron micro- scope and a transmission electron microscope （TEM）. The corresponding mechanical properties were also assessed by means of hardness and shear tests. The results showed a bonding interface formed between stainless steel and carbon steel, which was relatively straight in macroscope but serrated in microscope. Decarburization layer and carbon-enriched layer were distinguished at the side of carbon steel and stainless steel near the interface, respectively, which should be related to diffusion of carbon and alloying elements. The carbon-enriched layer could also be identified as a recombination region, whose microstructure was mainly recognized as martensite by TEM. Consequently, the hardness was the highest at this region. Furthermore, the result of shear test at the bonding interface showed that the shear strength was 395 MPa and the fracture mode was dominated as ductile fracture, indicating the bonding interface with good quality.

关键词： Stainless steel clad plate Vacuum hot rolling Interface microstructure Mechanical property

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全球变暖与季风

气候变化研究进展 2024年第1期20卷 118-120页

作者：赵宗慈罗勇黄建斌清华大学地球系统科学系北京100084 中国气象局国家气候中心北京100081 中国科学院大学资源环境学院北京100049

全球很多地区是季风气候,季风带来风和雨对人类生产和生活以及社会与经济发展有明显影响,因此,长期以来,季风是热门研究课题。根据有关研究,本文简述观测到的全球和区域季风变化,人类活动的影响,以及预估未来全球变暖背景下,全球和区域... 详细信息

全球很多地区是季风气候,季风带来风和雨对人类生产和生活以及社会与经济发展有明显影响,因此,长期以来,季风是热门研究课题。根据有关研究,本文简述观测到的全球和区域季风变化,人类活动的影响,以及预估未来全球变暖背景下,全球和区域的季风变化。

关键词：全球变暖热门研究课题社会与经济发展季风

超大尺寸高性能异材质多复合平板硫化机加热板的研究与开发

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锻压技术 2024年第5期49卷 102-108页

作者：邬早勤谢广明王磊骆宗安唐山文丰特钢有限公司河北唐山063200 东北大学轧制技术及连轧自动化国家重点实验室辽宁沈阳110819 河北工业大学材料科学与工程学院天津300131

采用真空焊接复合制备了45钢+Q355B钢的AB型坯料,并通过调整该AB型复合坯料加热时在加热炉的上、下烧嘴的加热负荷,对AB型钢板进行了不对称复合坯轧制。通过二次真空焊接复合制备了45钢+Q355B钢+Q355B钢+45钢的ABBA型坯料,并对焊缝进行... 详细信息

采用真空焊接复合制备了45钢+Q355B钢的AB型坯料,并通过调整该AB型复合坯料加热时在加热炉的上、下烧嘴的加热负荷,对AB型钢板进行了不对称复合坯轧制。通过二次真空焊接复合制备了45钢+Q355B钢+Q355B钢+45钢的ABBA型坯料,并对焊缝进行焊后高温回火处理,得到了ABBA型轧制复合板。结果表明:ABBA型复合板的界面为良好的冶金结合,平均硬度值为(180±10)HBW,组织成分均匀,各位置的硬度无明显差异。基材45钢中主要由片状珠光体和块状铁素体组成,复材Q355B钢主要由大量铁素体和少量珠光体组成。复合板厚度方向的断面收缩率平均值为62.67%,性能优异。此外,还实际生产了170 mm×3420 mm×10620 mm的ABBA型复合板,单重超过48000 kg。

关键词： 45钢 Q355B钢复合板轧制高温塑性

基于Resnet的林地无人机图像去雾改进算法

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南京林业大学学报（自然科学版） 2024年第2期48卷 175-181页

作者：牛弘健刘文萍陈日强宗世祥骆有庆北京林业大学信息学院北京100083 国家林业和草原局林业智能信息处理工程技术研究中心北京100083 北京林业大学林学院北京100083

【目的】针对雾霾天气下林地无人机航拍图像存在对比度低、饱和度低和色调偏移等现象,基于Resnet网络,提出一种适应林地航拍场景的无人机图像去雾方法(DHnet)。【方法】林地场景下无人机图像具有纹理特征、高低频信息丰富的特点,在主干... 详细信息

【目的】针对雾霾天气下林地无人机航拍图像存在对比度低、饱和度低和色调偏移等现象,基于Resnet网络,提出一种适应林地航拍场景的无人机图像去雾方法(DHnet)。【方法】林地场景下无人机图像具有纹理特征、高低频信息丰富的特点,在主干网络各个层级附加信息传递模块,将特征图转化为权值图进行筛选过滤并发送到其他层级,接收端设置阈值避免冗余信息的不良影响,再经密集链接增强全局去雾效果,提高图像高低频区域的去雾质量,最后在林地无人机有雾图像测试集上进行去雾实验。【结果】DHnet在林地图像测试集上的平均结构相似性为0.83,平均峰值信噪比为22.3 dB,分别较Resnet方法提高了4.8%和39.3%。【结论】本研究提出的算法能有效降低图像色调偏移,去除残留雾气信息,有效提高无人机航拍林地雾气图像的色彩保真度和细节信息保持度。

关键词：林地无人机图像去雾深度学习

风雨场中汽车乘员舱气动噪声声品质预测模型研究

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汽车技术 2024年第5期 51-57页

作者：宗轶琦张昊许国猛杨易罗泽敏扬州大学扬州225127 湖南大学长沙410082 广州汽车集团股份有限公司汽车工程研究院广州511434

为研究雨天行驶时汽车的声品质,对风雨场中汽车乘员舱气动噪声信号进行声品质客观参量计算和主观评价,并对二者进行了相关分析。采用基于改进鲸鱼优化算法的反向传播(IWOA-BP)算法,以响度、粗糙度、抖动度、语音清晰度、语言干扰度和声... 详细信息

为研究雨天行驶时汽车的声品质,对风雨场中汽车乘员舱气动噪声信号进行声品质客观参量计算和主观评价,并对二者进行了相关分析。采用基于改进鲸鱼优化算法的反向传播(IWOA-BP)算法,以响度、粗糙度、抖动度、语音清晰度、语言干扰度和声压级6个客观参数为输入,以主观评分作为输出,建立预测模型,并与传统的反向传播(BP)神经网络预测模型和鲸鱼优化算法-反向传播(WOA-BP)预测模型进行了对比。结果表明,BP、WOA-BP、IWOA-BP算法的平均绝对百分比误差分别为28.33%、6.35%和2.82%,证明了基于IWOA-BP算法建立的风雨场中汽车乘员舱气动噪声声品质预测模型精度更高,效果更好。

关键词：声品质风雨场气动噪声心理声学参数改进鲸鱼优化算法

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Effect of vacuum level on microstructure and mechanical properties of titanium-steel vacuum roll clad plates

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Journal of Iron and Steel Research(International) 2018年第1期25卷 72-80页

作者： De-han Yang zong-an luo Guang-ming Xie Ming-kun Wang R. D. K. Misra State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China Department of Metallurgical Materials and BiomedicalEngineering University of Texas at E1 Paso E1 PasoTX 79968 USA

Vacuum roll cladding （VRC） was used to bond pure titanium （Ti） plate to a plain low carbon steel （Q345） with the aim of obtaining a high-quality Ti-steel clad plate. The effect of interfacial compound on the mierostructure and mechanical properties of Ti-steel clad plate was studied by electron probe microanalysis, scanning electron microscopy, X-ray diffraction and shear test. The clad plates were heated at 850 ℃ for 120 min and welded at different levels of vacuum. The results indicated that the cracked zone of the bonded interface decreased significantly with the increase in the level of vacuum during welding. Welding at atmospheric pressure, the randomly distributed TiN damaged the continuity of TiC and the uniformly diffused region of Ti and Fe at the bonded interface, while welding in vacuum of 1 × 10^-2 Pa, maximum shear strength of 298 MPa was obtained because of the decrease in TiN content.

关键词： Vacuum roll cladding Ti-steel clad plate Shear strength Interface Intermetallic compound