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Journal of Iron and Steel Research International 2024年第3期31卷 622-633页

作者： Pu Wang Liang Chen Qun-wei Tang Wei-tao Li shao-xiang Li Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Weifang Special Steel Group Co..Ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were *** results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross *** cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or *** control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of *** this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： Continuous casting Soft reduction Crack propagation Internal quality Control strategy

Atroposelective Synthesis of 2-Arylindoles via Chiral Phosphoric Acid-Catalyzed Direct Amination of Indoles

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Chinese Journal of Chemistry 2024年第7期42卷 731-735页

作者： Wen Bao Ye-Hui Chen Yu-Wei Liu shao-Hua xiang Bin Tan School of Pharmacy&StateKey Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhouGansu 730000China Shenzhen Grubbs Institute Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong 518055China

Indole-based atropisomers are a very important class of axially chiral ***,the atroposelective synthesis of axially chiral 2-arylindole remains largely *** this study,we report the successful synthesis of atropisomeric 2-arylindoles using direct amination of indoles with p-quinonediimines in the presence of chiral phosphoric acid as a *** acts as an aminating reagent through formal polarity inversion of *** malonate group on the 2-aryl of 2-indoles was found to be essen-tial for high enantioselectivity of the *** could be due to the additional interaction between the ester group and the cata-lyst,as well as the intramolecular hydrogen *** findings provide a new strategy for the asymmetric construction of 2-arylindole atropisomers.

关键词： Chiral phosphoric acid Quinonediimines Direct amination Nucleophilic addition Asymmetric catalysis Enantioselectivity Axially chiral 2-arylindole Atroposelective synthesis

Improvement of impact properties of Al-Si-Mg alloy via solution treatment and joint modification with Sr and La

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Rare Metals 2024年第7期43卷 3301-3313页

作者： Xiong-Ling Zheng shao-xiang Li Jia-Le Ma Qing-Yan Xu Hai-Dong Zhao Zhi-Qiang Han Key Laboratory for Advanced Materials Processing Technology Ministry of EducationSchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China National Engineering Research Center of Near-Net Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510641China

An effort to obtain superior impact properties for Al-7Si-0.35 Mg alloy is presented,where modification with 0.02 wt% Sr and 0.1 wt% La as well as solution treatment was jointly *** samples were solution treated at 535℃ for 15 min to 12 *** microstructure,fracture mechanism,and their correlation with the impact properties of the alloy were studied in detail mainly through optical microscopy(OM),scanning electron microscopy(SEM) and oscillography impact *** results show that the addition of Sr and La refined the eutectic Si particles significantly from~ 2.05 μm(modified with Sr alone) to~ 0.75 μm in as-cast microstructure,leading to a very homogeneous distribution of spheroidized Si particles in the alloy solution treated at 535℃ for 8 *** alloy exhibits excellent impact toughness up to 75 J·cm^(-2),which is much higher than the maximum impact toughness of the alloys modified by Sr alone(~ 46 J·cm^(-2)).The major reason for this remarkable increase in the impact property is the dramatic increase in crack initiation *** dispersoid-free zones(DFZs)near the eutectic regions mainly consist of the ductile Al-matrix,which exhibits excellent *** ductile Al-matrix of the DFZs hinders the crack propagation,resulting in a significant increase in crack propagation energy.

关键词： Aluminum alloys Modification Solution treatment Microstructure Impact properties Fracture mechanism

Non-Gaussianity detection of single-mode rotationally symmetric quantum states via cumulant method

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Chinese Physics B 2024年第5期33卷 264-273页

作者：向少华黄利军米贤武 College of Physics Electronics and Intelligent ManufacturingHuaihua UniversityHuaihua 418008China

The non-Gaussianity of quantum states incarnates an important resource for improving the performance of continuous-variable quantum information *** propose a novel criterion of non-Gaussianity for single-mode rotationally symmetric quantum states via the squared Frobenius norm of higher-order cumulant matrix for the quadrature distribution *** an application,we study the non-Gaussianities of three classes of single-mode symmetric non-Gaussian states:a mixture of vacuum and Fock states,single-photon added thermal states,and even/odd Schr¨odinger cat *** is shown that such a criterion is faithful and effective for revealing *** further extend this criterion to two cases of symmetric multi-mode non-Gaussian states and non-symmetric single-mode non-Gaussian states.

关键词： non-Gaussianity criterion cumulant matrix quadrature distribution

AF-RetinaNet:一种基于自适应融合与特征细化的微小行人检测算法

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控制与决策 2024年第3期39卷 939-946页

作者：邵香迎郭颖王友伟南京信息工程大学江苏省大气环境与装备技术协同创新中心南京210044 南京信息工程大学自动化学院南京210044

为解决目前目标检测算法在微小行人的识别与定位过程中准确率较低的问题,提高微小行人检测能力,提出一种基于自适应融合与特征细化的微小行人检测算法AF-RetinaNet.首先,将特征增强模块与ResNet相结合构建特征提取网络,采用并行结构获... 详细信息

为解决目前目标检测算法在微小行人的识别与定位过程中准确率较低的问题,提高微小行人检测能力,提出一种基于自适应融合与特征细化的微小行人检测算法AF-RetinaNet.首先,将特征增强模块与ResNet相结合构建特征提取网络,采用并行结构获得增强特征;其次,使用上下文自适应学习模块,通过获得目标上下文的特征信息,从而关注相似特征的差异性,缓解误检问题;最后,构造具有图像超分思想的特征细化模块,对目标特征信息进行放大重构,优化小目标的特征表达能力,缓解漏检问题.在TinyPerson数据集上, AF-RetinaNet算法的检测精度达到56.78%,漏检率达到85.38%.与基于RetinaNet算法的研究基准相比,检测精度提高5.57%,漏检率降低3.67%.实验结果表明,该模型能有效提高对微小行人的检测和识别精度.

关键词：机器视觉微小行人小目标检测特征增强上下文信息特征细化

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伸缩式钻孔机器人动力学模型及仿真分析研究

机械设计与制造 2024年第8期402卷 333-338,345页

作者：许敏邵向阳漯河医学高等专科学校河南漯河462000

钻孔机器人在油矿井下作业环境中逐渐广泛应用,提出了一种由钻孔液驱动的新型伸缩式钻孔机器人。首先根据钻孔机器人驱动力的工作原理,建立了压差流体力学模型,在此基础上分别推导了钻孔机器人在空载和负载条件下的牵引力计算方程,从而... 详细信息

钻孔机器人在油矿井下作业环境中逐渐广泛应用,提出了一种由钻孔液驱动的新型伸缩式钻孔机器人。首先根据钻孔机器人驱动力的工作原理,建立了压差流体力学模型,在此基础上分别推导了钻孔机器人在空载和负载条件下的牵引力计算方程,从而建立了钻孔机器人的动力学模型,提出了钻压、钻速等关键参数的计算方法。通过仿真分析了表明,随着流量的增加,钻速/速度和钻孔机器人的牵引力均呈近似线性增加趋势,在空载条件下,钻孔机器人将处于加速状态,直到伸缩缸停止泵送钻孔液为止。在负载条件下,钻孔机器人与机械钻孔速率能快速达到平衡。

关键词：钻孔机器人伸缩式机器人钻孔液驱动压差

检测铁离子和肼的双功能荧光探针的合成与应用

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分析化学 2024年第6期52卷 809-827页

作者：端宁丁乐媛邓兵杨绍祥北京工商大学轻工科学技术学院

以6-甲氧基-2-乙酰萘为原料，通过两步反应方法合成了一种新的席夫碱荧光探针DFFH，采用核磁共振氢谱（1H NMR）、碳谱(13C NMR)和高分辨质谱（HRMS）表征其结构，并考察了其光谱性质。在乙醇-水（EtOH-H2O,1:4,V/V）体系中，探针DFFH中... 详细信息

以6-甲氧基-2-乙酰萘为原料，通过两步反应方法合成了一种新的席夫碱荧光探针DFFH，采用核磁共振氢谱（1H NMR）、碳谱(13C NMR)和高分辨质谱（HRMS）表征其结构，并考察了其光谱性质。在乙醇-水（EtOH-H2O,1:4,V/V）体系中，探针DFFH中的4-羟基苯胺部分与Fe3+按摩尔比1:1络合后，在386 nm处的荧光强度明显下降；在二甲基亚砜-水（DMSO-H2O,9:1,V/V,pH=5）体系中，少量肼（N2H4）可诱导探针DFFH酚对氨基苯酚部分的肼解，同时N2H4和探针DFFH中的α,β-不饱和羰基发生环化加成反应，具有比率型荧光识别特性。基于上述原理，实现了对Fe3+和N2H4的灵敏检测。加入Fe3+后，探针DFFH溶液的发光强度略有降低；同时，随着N2H4浓度增大，探针DFFH溶液由无色变为黄棕色，两者检测互不干扰。探针对Fe3+和N2H4具有较好的灵敏度和选择性，检出限（LOD,3σ）分别为34.0 nmol/L和30.0 nmol/L。采用此探针检测不同水样中Fe3+和N2H4的含量，回收率分别在96.5%～102.3%和98.1%～103.0%之间，表明探针DFFH可用于实际水样中Fe3+和N2H4含量的检测。

关键词：双功能荧光探针铁离子肼水样

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大悬臂预应力盖梁空间托架体系设计与施工研究

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北方建筑 2024年第1期9卷 68-73页

作者：邵翔中铁十六局集团第三工程有限公司浙江湖州313000

本文以G316长乐漳港至营前段A2合同段大悬臂预应力盖梁施工为工程背景,结合桥梁所处的施工环境及地质条件,对比分析了盘扣式支架、钢管组合支架及空间托架法支架的优缺点,设计了由牛腿、斜撑、主支撑梁、横向分配梁等组成的空间托架体... 详细信息

本文以G316长乐漳港至营前段A2合同段大悬臂预应力盖梁施工为工程背景,结合桥梁所处的施工环境及地质条件,对比分析了盘扣式支架、钢管组合支架及空间托架法支架的优缺点,设计了由牛腿、斜撑、主支撑梁、横向分配梁等组成的空间托架体系。采用有限元软件对所设计支架在不同工况下的应力、变形及稳定性等性能进行了详细的检算。结果表明,大悬臂预应力盖梁采用空间托架法具备安全可靠性。

关键词：大悬臂预应力盖梁空间托架体系结构设计及检算施工工序