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面向大气湍流畸变场景的卷积图像校正方法

计算机工程与应用 2024年第11期60卷 215-223页

作者：成宽洪吴钰博朱凌建李佳李军怀西安理工大学计算机科学与工程学院西安710048 西安理工大学机械与精密仪器工程学院西安710048 中国人民解放军空军工程大学基础部西安710051

大气湍流引发的折射率在时间和空间上的随机波动,会使远程成像系统捕获的图像出现时空模糊和几何畸变,严重削弱了图像的视觉效果和应用价值。针对这一问题,许多学者尝试采用多帧幸运区的方法和基于卷积神经网络的深度学习方法来修复大... 详细信息

大气湍流引发的折射率在时间和空间上的随机波动,会使远程成像系统捕获的图像出现时空模糊和几何畸变,严重削弱了图像的视觉效果和应用价值。针对这一问题,许多学者尝试采用多帧幸运区的方法和基于卷积神经网络的深度学习方法来修复大气湍流引起的图像畸变。然而,在强湍流情况下,这些方法通常模型训练难度较大,湍流自适应性校正能力较为薄弱。为了解决上述问题,经研究提出了一种改进的深度学习网络来提升湍流畸变校正的性能。该网络采用Transformer端到端的网络结构,利用多头自注意力跨通道捕获局部上下文信息;对一级校正网络采用蒙特卡洛Dropout策略进行训练,通过模型不确定性来提取传统方法难以捕获的退化区域;利用提取到的不确定性映射作为引导信息,输入第二级校正网络提升校正准确性。在基于时空模糊加几何畸变的合成湍流退化图像集上进行了实验,证明了提出方法的有效性。

关键词：图像处理大气湍流自注意力机制不确定性映射

Fatigue properties of titanium alloy custom short stems fabricated by electron beam melting

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Journal of Materials Science & Technology 2020年第17期52卷 180-188页

作者： Liao Wang Shujun Li Mengning Yan Yubo Cheng Wentao Hou Yiping Wang Songtao Ai Rui Yang Kerong Dai Shanghai Key Laboratory of Orthopaedic Implants Department of Orthopaedic SurgeryShanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai Jiao Tong UniversityShanghai 200030China Titanium Alloy Laboratory Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Image Medraw Technology(Shanghai)Company Limited Shanghai 201100China

The fatigue properties of titanium alloy short-stems with four different lengths,manufactured by electron beam melting(EBM)technology,were investigated by in vitro test and finite element(FE)analysis.FE simulation results indicate that the maximum tensile stress concentrates at the lateral side of the stem body.The magnitude of the concentrated tensile stress increases and the corresponding area of the axial section decreases with increasing of stem length.Results from fatigue tests demonstrate that fatigue cracks mainly initiate from the rough surface of the stem where the maximum tensile stress concentrates.The fatigue strength decreases with the increase of stem length,which is attributed to the higher stress concentration on the longer stem surface.In addition,it is found that post EBM treatment via hot isostatic processing(HIP)is able to enhance the fatigue properties of the stems,since the pores generated during EBM are mostly closed during HIP.Our work also demonstrates that the stress concentration on the stem surface can be effectively mitigated and the corresponding fatigue properties of the EBM-fabricated titanium alloy short stem can be considerably improved by optimizing the design in the stem length.

关键词： Custom short stem Titanium alloy Electron beam melting Fatigue property

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计量经济学教学模式改革研究

科教导刊 2024年第9期 77-80页

作者：李圣华成玉博延边大学经济管理学院吉林延吉133002 延边大学融合学院吉林延吉133002

文章以延边大学经济管理学院国际经济与贸易专业学生期末成绩作为评价指标,分析了计量经济学课程的教学效果。通过问卷调查的形式,对学生的学习情况进行了调查,发现课程教学中存在课时少,课程安排不合理;学生基础知识储备不足;教学内容... 详细信息

文章以延边大学经济管理学院国际经济与贸易专业学生期末成绩作为评价指标,分析了计量经济学课程的教学效果。通过问卷调查的形式,对学生的学习情况进行了调查,发现课程教学中存在课时少,课程安排不合理;学生基础知识储备不足;教学内容和方法缺乏全面性;考试分值占比不平衡,考核方式单一等问题。根据分析结果,从课程安排、教学方式、教学内容以及考核方式等视角,提出了计量经济学教学改革的相关建议。

关键词：计量经济学教学模式教学改革

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考虑圆孔扩散时盾构注浆引起的土体变形分析

科技通报 2024年第5期40卷 73-78页

作者：陈威孙兴鹏程钰博孙阳中国电建集团华东勘测设计研究院有限公司杭州311100 河海大学港口海岸与近海工程学院南京210098 河海大学淮安研究院江苏淮安223001

本文基于弹性力学Mindlin基本解和坐标变换,假设盾尾注浆浆液为牛顿流体,考虑盾尾浆液在一定厚度范围内沿柱面均匀圆形扩散,得到注浆压力竖向分量和水平分量引起的土体竖向位移解,并以某工程盾构施工段为例,分别计算了注浆压力简化为均... 详细信息

本文基于弹性力学Mindlin基本解和坐标变换,假设盾尾注浆浆液为牛顿流体,考虑盾尾浆液在一定厚度范围内沿柱面均匀圆形扩散,得到注浆压力竖向分量和水平分量引起的土体竖向位移解,并以某工程盾构施工段为例,分别计算了注浆压力简化为均布荷载和考虑圆孔扩散的竖向位移。结果表明:2种方法计算得到的土体的位移曲线均呈现正态分布,距离注浆面越近,土体隆起变形就越大;考虑注浆压力圆孔扩散时,计算得到的地表隆起值约为均布注浆压力的3倍;考虑圆孔扩散的位移公式包含了注浆压力、注浆时间、注浆孔径和浆液特性等参数,通过调整这些参数能够改善盾尾注浆引起的土体变形。

关键词：盾构施工圆孔扩散 Mindlin解注浆压力土体变形

立式连铸P91钢大圆坯表面纵裂缺陷及其控制

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中国冶金 2024年第5期34卷 65-73页

作者：宗健董延楠涂高岭程晃潘禹博张家泉北京科技大学冶金与生态工程学院北京100083 河南中原特钢装备制造有限公司高洁净钢公司河南济源459008

P91钢为微合金化改良型9Cr-1Mo马氏体耐热钢,具有良好的高温强度、高温抗氧化性和抗腐蚀性,是当前先进的电站用大口径高温高压蒸汽管道制备材料。针对国内外以坯代锭、开发圆坯连铸高合金钢高效制备工艺的需要,研究分析了P91钢连铸圆坯... 详细信息

P91钢为微合金化改良型9Cr-1Mo马氏体耐热钢,具有良好的高温强度、高温抗氧化性和抗腐蚀性,是当前先进的电站用大口径高温高压蒸汽管道制备材料。针对国内外以坯代锭、开发圆坯连铸高合金钢高效制备工艺的需要,研究分析了P91钢连铸圆坯常见的表面纵裂问题及其影响因素。基于低倍观察、OM、SEM与EDS分析,揭示了这类表面裂纹的形貌、组织与成分特征;利用相变热力学计算揭示了其高温初凝的相变特点。研究表明,P91高合金钢具有亚包晶钢的凝固特点,其在结晶器弯月面附近可能发生的强烈δ→γ相变收缩是连铸坯壳凹陷与纵裂倾向大的内在诱因,浇注工艺不良所导致的初凝坯壳与气隙不均是造成裂纹发生的重要外部因素;P91钢圆坯纵裂起源于连铸结晶器内。生产试验表明,通过合理选择水口、控制钢水注流对初凝坯壳的冲刷,选用合适黏度与熔点的保护渣、增加液渣层厚度及其对坯壳气隙的充填能力等措施,均能从连铸工艺上不同程度地控制P91连铸圆坯的表面纵裂率;进一步优化设计结晶器铜管冷却结构,适当弱化一冷强度、提高结晶器周向冷却的均匀性,可以更有效地控制其连铸表面纵裂缺陷的发生率。研究结果可为P91等高合金钢圆坯连铸生产中表面纵裂的控制提供参考。

关键词： P91钢大圆坯连铸表面纵裂生产与控制

In vitro and in vivo evaluation of micro-alloyed magnesium for potential application in alveolar bone fixation screws

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Journal of Materials Science & Technology 2023年第13期144卷 62-69页

作者： Hongyan Tang Qing Li Min Li Xuenan Gu chengkung cheng yubo Fan Key Laboratory of Biomechanics and Mechanobiology(Beihang University) Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China Center of Digital Dentistry Peking University School and Hospital of StomatologyBeijing 100081China National Engineering Research Center of Oral Biomaterials and Digital Medical Devices Beijing 100081China School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200030China

Alveolar bone augmentation with fixation screws has difficulties such as non-degradable materials that could lead to secondary surgery and insufficient osseointegration due to the subgingival environment in dental practice.With degradability and a high degree of osteogenesis,Mg alloy is a successful biodegrad-able material for orthopedic applications,and its application in dentistry has made certain progress.How-ever,considering the unique subgingival healing properties of oral implants,there is still a gap between the desired material properties for clinical applications and available materials.Indeed,studies on the use of Mg-based fixation screws for dentistry applications are still rare.In this study,we reported a magnesium alloy with low combined addition of strontium and lanthanum.The mechanical properties,degradation behavior,osteogenesis,and gingival compatibility were systematically investigated for assess-ing its potential application in alveolar bone fixation screws.With the alloying element content restricted to 0.3 wt.%,Mg-Sr-La alloy still exhibited good mechanical properties,with yield tensile and compressive strength twice higher than those of pure Mg.The in vitro degradation rate of this alloy was 0.10 mm y-1,which was slightly slower than high-purity Mg.The indirect and direct cell assay confirmed the elevated osteoblastic differentiation of MC3T3-E1 and migration of HGF-1 cells.Moreover,Mg-Sr-La alloy demon-strated a relatively slow degradation in the maxillary bone of Beagles.A remarkable promotion of the bone-implant contacts and significantly decreased fibrous encapsulation was observed in the subgingival environment,implying superior osseointegration of the experimental alloy than the titanium control.The empirical findings here reveal the great potential of Mg-Sr-La alloy for the application in alveolar bone fixation devices.

关键词： Magnesium alloys Alveolar ridge augmentation Fixation screws Osseointegration

Anti-inflammatory sesquiterpene polyol esters from the stem and branch of Tripterygium wilfordii

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Chinese Journal of Natural Medicines 2023年第3期21卷 233-240页

作者： HU Yalin XU Tianqi YIN Wenjing cheng Huaiyu ZHANG Xia LIU Ying ZHANG yubo ZHOU Guangxiong Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research Institute of Traditional Chinese Medicine and Natural ProductsCollege of PharmacyJinan UniversityGuangzhou 511436China Department of Pharmacology School of MedicineGuangdong Clinical Translation Center for Targeted DrugJinan UniversityGuangzhou 511436China

The stem and branch extract of Tripterygium wilfordii(Celastraceae)afforded seven new dihydroagarofuran sesquiterpene polyesters[tripterysines A‒G(1‒7)]and eight known ones(8‒15).The chemical structures of these new compounds were established based on combinational analysis of HR-ESI-MS and NMR techniques.The absolute configurations of tripterysines A‒C(1‒3)and E‒G(5‒7)were determined by X-ray crystallographic analysis and circular dichroism spectra.All the compounds were screened for their inhibitory effect on inflammation through determining their inhibitory effect on nitric oxide production in LPS-induced RAW 264.7 cells and the secretion of inflammatory cytokines TNF-αand IL-6 in LPS-induced BV2 macrophages.Compound 9 exhibited significant inhibitory activity on NO production with an IC50 value of 8.77μmol·L−1.Moreover,compound 7 showed the strongest inhibitory effect with the secretion of IL-6 at 27.36%.

关键词： Tripterygium wilfordii Sesquiterpene polyester Tripterysine Anti-inflammation

Hot-top direct chill casting assisted by a twin-cooling field:Improving the ingot quality of a large-size 2024 Al alloy

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Journal of Materials Science & Technology 2022年第17期112卷 114-122页

作者： cheng Zhu Zhihao Zhao Qingfeng Zhu Gaosong Wang yubo Zuo Qiangqiang Li Gaowu Qin Research Center for Metallic Wires School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China Key Laboratory of Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China

Microstructure inhomogeneity and negative segregation have long been challenges for large-size alloy ingots,directly affecting the downstream processing and final performance of products.Here,we used2024 aluminum alloy as a model alloy to propose a technique,named double-cooling field casting,i.e.,one 2024 Al alloy rod(Φ20 mm)at room temperature was introduced into the melt along the central axis of the hot-top with the protection of a thermal-insulation tube during the direct chill(DC)casting process of aΦ300 mm 2024 Al alloy ingot.The results show that the introduction of the same alloy solid insert has a remarkable influence on refining grains in the center region of the ingot,reducing negative centerline segregation and decreasing the depth of the center part of the sump.With the application of the 2024 Al insert,the mean size of equiaxed grains at the center part of the ingot decreased from1204±132μm to 721±69μm.The relative deviation of the Cu and Mg main solutes reduced from-0.062 and-0.054 to-0.03 and-0.024,respectively,and the sump depth decreased from 280 mm to242 mm.Moreover,the shape of the solidification front was changed from‘V’-shaped to‘W’-shaped.The ingot quality was thus improved,mainly arising from the dissolution of the cold 2024 Al insert at a proper position of the hot-top counteracting some latent heat of solidification of the ingot,dissipating the heat of the central part of the hot-top by conducting the 2024 Al insert to the outside,and providing extra-nuclei from the unmoltenα-Al particles of the insert.

关键词： Aluminum alloy DC casting Solid insert Grain refinement Macrosegregation

体细胞克隆技术扩繁超细型二狼山绒山羊的应用研究

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中国畜牧兽医 2024年第4期51卷 1420-1427页

作者：卿玉波程雯角德灵刘城郝志强郭建雄李钰莹张筱琳李臻李效宇王文魏红江云南省小型猪基因编辑与异种器官移植重点实验室昆明650201 云南农业大学动物医学院昆明650201 云南农业大学动物科学技术学院昆明650201 内蒙古中科正标生物科技有限公司巴彦淖尔015000 内蒙古正标种畜有限公司巴彦淖尔015000 中国科学院昆明动物研究所昆明650201

【目的】通过体细胞克隆技术生产超细型二狼山绒山羊克隆个体,为该技术在地方优质羊品种资源扩繁及新品种培育中的应用提供理论依据。【方法】选择1只4岁龄羊绒细度为13.89μm的二狼山绒山羊(♂),采集耳组织并分离培养成纤维细胞,以其... 详细信息

【目的】通过体细胞克隆技术生产超细型二狼山绒山羊克隆个体,为该技术在地方优质羊品种资源扩繁及新品种培育中的应用提供理论依据。【方法】选择1只4岁龄羊绒细度为13.89μm的二狼山绒山羊(♂),采集耳组织并分离培养成纤维细胞,以其为供体细胞,利用体细胞克隆技术开展超细型二狼山绒山羊的扩繁研究,通过克隆羊体重、羊绒细度、繁殖性能等指标评估该技术的可行性。【结果】试验成功建立了稳定的山羊卵母细胞体外成熟培养及体细胞克隆技术体系,卵母细胞成熟率为44.8%,孤雌激活卵裂率、囊胚率分别为83.0%、22.4%;二狼山绒山羊克隆胚的卵裂率、囊胚率分别为77.8%、13.7%。获得5只克隆羊个体,其生长发育正常,二狼山绒山羊母羊自然交配共获得16只健康的F1代个体,具有正常繁殖能力。克隆个体羊绒细度极显著低于同龄对照个体(P<0.01)。【结论】本研究通过体细胞克隆技术成功克隆了超细型二狼山绒山羊个体,其具备正常生产性能和繁殖性能,并保留了超细羊绒的特性,为地方优良羊种质资源扩繁和新品种培育应用研究奠定了基础。

关键词：二狼山绒山羊体细胞克隆羊绒细度繁殖性能