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Adaptive sampling for corrugated plate digitization using a laser displacement sensor

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Science China(Technological Sciences) 2024年第5期67卷 1510-1523页

作者： WU ChengXing QI Qi CHEN BaiJin YANG JiXiang ding han State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical *** detection methods are impractical for real-world production,being slow and *** contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective *** its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data *** address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate *** process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting ***,dominant points are identified,considering multigeometric constraints for curvature and arch ***,the sampling signal is adjusted based on the distribution information of dominant *** results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.

关键词： corrugated plate laser displacement sensor adaptive sampling dominant point curvature arch height

Water modeling on fluid flow and mixing phenomena in a BOF steelmaking converter

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Journal of Iron and Steel Research International 2024年第3期31卷 595-607页

作者： Xin-yu Cai Hao-jian Duan ding-han Li Anjun Xu Li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A 1∶8 physical water model was constructed to investigate the fluid flow and mixing phenomena in the basic oxygen furnace(BOF)*** particle image velocimetry was employed to measure the velocity distribution of the bath and the high-speed camera was applied to capture the cavity shape in the combined blowing BOF *** mixing time for varied operating conditions was measured by the stimulus-response *** cavity depth increased with the decrease in the lance height and the increase in the top gas flow rate while the bottom blowing gas had little influence on the cavity *** minimum cavity depth was obtained under the condition of a 69.8 m^(3)/h top gas flow rate,a 287.5 mm lance height and a 0.93 m^(3)/h bottom blowing gas flow rate,which was 161.2 *** mixing time decreased as the lance height decreased and the top blowing gas flow rate *** mixing time was first decreased and then increased with the increase in the bottom gas flow *** the condition of 69.8 m^(3)/h gas flow rate of top blowing,the 287.5 mm lance height and the 0.93 m^(3)/h gas flow rate of bottom blowing,the mixing time in the converter was 48.65 *** empirical formula between the stirring power and the mixing time in the converter was calculated.

关键词： Water model Fluid flow Particle image velocimetry Mixing time BOF converter

Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction

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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： ding-han Zhu Xiong Zhang Xiao-Qiang Li Peng Li Yan-Bin Wang Shuang Zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method

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稀土发光纳米材料在手印显现中的应用进展

光谱学与光谱分析 2024年第6期44卷 1501-1511页

作者：丁寒中国政法大学刑事司法学院北京102249

自2000年起,研究人员陆续将一系列新型纳米材料应用到手印显现中,由此衍生了手印纳米显现技术。显现材料的推陈出新和显现方法的借鉴创新共同促进了手印纳米显现技术的迅速发展。近十年来,将稀土发光纳米材料应用于手印纳米显现技术的... 详细信息

自2000年起,研究人员陆续将一系列新型纳米材料应用到手印显现中,由此衍生了手印纳米显现技术。显现材料的推陈出新和显现方法的借鉴创新共同促进了手印纳米显现技术的迅速发展。近十年来,将稀土发光纳米材料应用于手印纳米显现技术的研究报道日益增多,已经逐渐成为该领域的研究热点之一。基于稀土发光纳米材料的手印显现技术具有对比度强、灵敏度高、选择性佳、毒害性低等突出优势,因此具备重要的理论研究价值和广阔的实践应用前景。目前,该研究领域的文献报道形式主要为研究类文章,鲜有涉及综述类文章。该文从显现材料的推陈出新和显现方法的借鉴创新两个方面综述了稀土发光纳米材料在手印显现中的研究进展。在显现材料的推陈出新方面,总结了基于稀土下转换发光纳米材料、稀土上转换发光纳米材料、复合型稀土发光纳米材料的手印显现应用;在显现方法的借鉴创新方面,总结了基于静电吸附原理、疏水作用原理、化学键合原理、适配体识别原理的手印显现方法。基于稀土发光纳米材料的手印显现研究呈现出如下发展趋势:显现材料由下转换发光材料向上转换发光材料发展,由单一发光材料向多重发光材料发展,由光致发光材料向功能复合材料发展;显现方法由非特异显现向靶向性显现发展,由痕迹物证的定性显现向遗留物质的定量检测发展,由物理显现向化学显现发展;显现效果由痕迹特征的宏观无损向生物物证的微观无损发展;显现操作由潜在毒害向绿色环保发展;显现评估由主观、片面、定性描述向客观、全面、定量分析发展。该综述对基于稀土发光纳米材料的手印显现技术提出了如下展望:首先是纳米材料的物理性质对手印显现效果的影响研究,其次是纳米材料的诸多性质对生物物证检验的影响研究,最后是显现原理的广泛借鉴与显现方法的深度开发研究。

关键词：手印显现潜在手印纳米材料稀土发光

Human umbilical cord mesenchymal stem cell-derived exosomes loaded into a composite conduit promote functional recovery after peripheral nerve injury in rats

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Neural Regeneration Research 2024年第4期19卷 900-907页

作者： Haoshuai Tang Junjin Li Hongda Wang Jie Ren han ding Jun Shang Min Wang Zhijian Wei Shiqing Feng Department of Othopaedics Tianjin Medical University General Hospital International Science and Technology Cooperation Base of Spinal Cord Injury Tianjin Key Laboratory of Spine and Spinal Cord InjuryDepartment of OrthopedicsTianjin Medical University General Hospital Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment Tianjin Lung Cancer InstituteTianjin Medical University General Hospital Department of Othopaedics Qilu Hospital of Shandong UniversityShandong University Centre for OthopedicsAdvanced Medical Research InstituteShandong University Orthopedic Research Center of Shandong University&Advanced Medical Research Institute Cheeloo College of MedicineShandong University

Complete transverse injury of peripheral nerves is challenging to *** secreted by human umbilical cord mesenchymal stem cells are considered to play an important role in intercellular communication and regulate tissue *** previous studies,a collagen/hyaluronic acid sponge was shown to provide a suitable regeneration environment for Schwann cell proliferation and to promote axonal *** three-dimensional(3D)composite conduit contains a collagen/hyaluronic acid inner sponge enclosed in an electrospun hollow poly(lactic-co-glycolic acid)***,whether there is a synergy between the 3D composite conduit and exosomes in the repair of peripheral nerve injury remains *** this study,we tested a comprehensive strategy for repairing long-gap(10 mm)peripheral nerve injury that combined the 3D composite conduit with human umbilical cord mesenchymal stem cell-derived *** effectiveness was evaluated by sciatic functional index,sciatic nerve compound muscle action potential recording,recovery of muscle mass,measuring the cross-sectional area of the muscle fiber,Masson trichrome staining,and transmission electron microscopy of the regenerated nerve in *** results showed that transplantation of the 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes promoted peripheral nerve regeneration and restoration of motor function,similar to autograft *** CD31-positive endothelial cells were observed in the regenerated nerve after transplantation of the loaded conduit than after transplantation of the conduit without exosomes,which may have contributed to the observed increase in axon regeneration and distal nerve ***,the use of a 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes represents a promising cell-free therapeutic option for the treatment of peripheral nerve injury.

关键词： axon growth collagen exosome human umbilical cord mesenchymal stem cells hyaluronic acid muscular atrophy nerve guidance conduits peripheral nerve regeneration

俞樾的运河情结及其《右台仙馆笔记》中的运河书写

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明清小说研究 2024年第2期 134-147页

作者：丁涵南开大学文学院

晚清学术宗师俞樾的《右台仙馆笔记》被公认是继纪昀的《阅微草堂笔记》之后在小说史上最重要的一部文言笔记小说。该作品中丰富多样的运河书写,对运河本身及沿岸城乡的自然风光和人文风貌均有广泛且生动的描写和细致且深邃的反思。这... 详细信息

晚清学术宗师俞樾的《右台仙馆笔记》被公认是继纪昀的《阅微草堂笔记》之后在小说史上最重要的一部文言笔记小说。该作品中丰富多样的运河书写,对运河本身及沿岸城乡的自然风光和人文风貌均有广泛且生动的描写和细致且深邃的反思。这与作者因其成长环境和生活经历所形成的运河情结息息相关,而俞樾对运河抱有的熟悉、热爱和怀念的浓重运河情结也深刻影响了小说内的素材选择、故事选址、人物分布、情节转换和价值判断。因此,《右台仙馆笔记》不仅具有珍贵的运河文化之文献价值,还蕴含着典型的以运河为主要背景的小说之研究意义。

关键词：俞樾《右台仙馆笔记》运河情结运河书写

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论汉晋“势体文”的成立与隐退

南开学报（哲学社会科学版） 2024年第4期 60-71页

作者：丁涵南开大学文学院天津300071

“势”原是一种内涵丰富的书学专论文体。汉末至西晋期间,“势体文”从初兴直至鼎盛具备了特定的历史条件:一是书体和文体大备;二是书论和文论昌明。作为早期书学和文学交汇发展的产物,势体文不但显著地标志着书学史上书法艺术的提升和... 详细信息

“势”原是一种内涵丰富的书学专论文体。汉末至西晋期间,“势体文”从初兴直至鼎盛具备了特定的历史条件:一是书体和文体大备;二是书论和文论昌明。作为早期书学和文学交汇发展的产物,势体文不但显著地标志着书学史上书法艺术的提升和书法审美的自觉,而且集中地反映了文学史上文体意识的进步和文体理论的成熟。此外,它由盛而衰的轨迹还可折射出其时书风移变和文体竞争的影响,从而为观照中古“技艺”文体兴衰浮沉现象背后的复杂原因提供合理的解释和参考。

关键词： “势” 书体 “技艺”文体书学史和文学史

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用户可见性对大众生产的影响机制研究

新闻大学 2024年第1期213卷 91-103,122页

作者：丁汉青朱婧北京师范大学新闻传播学院北京100875

本文以百度百科为例,采用网络民族志与参与式观察法,从可见性视角探讨大众生产何以可能。研究发现,大众生产平台通过规则设定再分配用户活动数据,使用户可见性差异化。差异化可见建构出生产者与浏览者间以“看见”与“被看见”为形态的... 详细信息

本文以百度百科为例,采用网络民族志与参与式观察法,从可见性视角探讨大众生产何以可能。研究发现,大众生产平台通过规则设定再分配用户活动数据,使用户可见性差异化。差异化可见建构出生产者与浏览者间以“看见”与“被看见”为形态的弱关系和生产者间以“竞争”“合作”为形态的强关系。强弱关系赋予用户生产以意义,构成用户投身生产的三种动力:因“观看关系”而强化的生产优质内容动力、基于“竞争关系”的生产更多内容的动力和基于“合作关系”的持续生产动力。“用户可见性—关系—动力”环环相扣,成就欣欣向荣的大众生产图景。本研究展现出多向度“关系”在解释大众生产机制中的张力,打破了平台—用户二者之间“控制—被控制”的二元论的局限。

关键词：用户可见性大众生产用户关系生产动力百度百科

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面向多联体叶片的机器人喷涂无干涉路径规划

机械工程学报 2024年第1期60卷 210-219页

作者：漆琪刘礼祥杨吉祥丁汉华中科技大学智能制造装备与技术全国重点实验室武汉430074 中国航发沈阳黎明航空发动机有限责任公司沈阳110043

多联体叶片存在曲面复杂、叶片间距小等结构特点。等离子喷涂为铸造多联体叶片的重要工序,可使叶片表面强化与改性,其喷涂质量直接决定叶片的成品率与性能。现有的机器人等离子喷涂的路径生成主要依靠手动示教,而喷涂过程中的喷涂距离... 详细信息

多联体叶片存在曲面复杂、叶片间距小等结构特点。等离子喷涂为铸造多联体叶片的重要工序,可使叶片表面强化与改性,其喷涂质量直接决定叶片的成品率与性能。现有的机器人等离子喷涂的路径生成主要依靠手动示教,而喷涂过程中的喷涂距离与喷涂夹角无法量化导致喷涂质量不均且示教方法繁琐、效率低。基于此,提出一种面向多联体叶片的工业机器人等离子喷涂无干涉路径生成及光顺方法。首先,根据CAD模型,将多联体叶片型面转为非均匀有理B样条(NURBS)曲面,利用NURBS曲面解析特性,生成约束喷涂行距与喷涂叶片边缘距离的初始路径点;然后将喷涂焰流简化为方向包围盒,将干涉曲面转为三角面片,采用基于分离轴检测的方法进行碰撞干涉检测,生成考虑最小喷涂倾角约束的喷涂姿态。采用基于球面样条四元数插值变步长姿态优化方法进行姿态光顺,生成无干涉且路径光顺的喷涂路径。经过仿真与实验验证,提出干涉避免算法能有效避免喷涂过程中的干涉现象。对比未光顺路径,所提出算法机器人运行效率提高52.6%,机器人振动下降,运行更加平稳,其中关节加速度最大下降55.8%,最小下降2.9%,末端瞬时加速度最大下降39.6%,最小下降14.4%。

关键词：多联体叶片机器人喷涂干涉检测路径光顺