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Numerical simulation and method study of X-ray litho-density logging

Nuclear Science and Techniques 2020年第12期31卷 129-138页

作者： Hua-Wei Yu Yu-Xin Zhang Xiang-hong Chen wen-ding Wang Chao-Zhuo Liu Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580China School of Geosciences China University of Petroleum(East China)Qingdao 266580China College of Science China University of Petroleum(East China)Qingdao 266580China

To effectively replace the isotope radiation source in litho-density logging,this study presents a method for measuring the formation density and photoelectric absorption index(Pe)using a switchable X-ray ***,the gamma-ray litho-density logging(GLD)method for measuring formation density and Pe using chemical sources is ***,a benchmark verification based on the X-ray litho-density logging tool prototype and data published by Simon(In:Paper presented at the SPWLA 59th annual logging symposium,London,UK,2018)was carried out using Monte Carlo numerical ***,the impacts of the photoelectric effect and detector statistical error on the GLD method were ***,based on a theoretical analysis,the formation density and Pe measurement algorithm(double energy window(DEW)method)was improved,which was found to be suitable for X-ray litho-density ***,the results obtained using this algorithm were compared with those obtained using the GLD *** results indicate that owing to the impact of photoelectric effect and detector statistical error on the density energy window,the accuracy of formation density and Pe measurement using the GLD method is relatively low,with the uncertainty in formation density and Pe measurement reaching 2.620±0.047 g/cm3 and 4.090±0.580 b/e,*** comparison,the DEW method can improve the accuracy of density and Pe measurement to 0.006 g/cm3 and 0.065 b/e,respectively,as the photoelectric effect in the density window is corrected using the counts in the lithology window of the energy *** study aims to provide a new theoretical foundation for processing X-ray litho-density logs in the future.

关键词： X-ray controllable source Litho-density logging Monte Carlo simulation

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Direct asymmetric aldol reaction using MBHA resin-supported peptide containing L-proline unit

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Chinese Chemical Letters 2009年第9期20卷 1065-1067页

作者： Liang Zhang wen Bo ding Yong Ping Yu hong Bin Zou Institute of Materia Medica College of Pharmaceutical Sciences Zhejiang University Hangzhou 310058 China

MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes, which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses. 2009 hong Bin Zou. Published by E]sevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Direct asymmetric aldol reaction MBHA resin-supported peptide L-Proline "Tea-bag" methodology

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Microstructure and mechanical properties of two-stage aged Al-Cu-Mg-Ag-Sm alloy

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Rare Metals 2019年第1期38卷 42-51页

作者： wen-Long Zhang Dai-hong Xiao Ting Li Jian-Di Du Dong-Yan ding State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Science and Technology on High Strength Structural Materials Laboratory Central South University

High-strength Al-Cu-Mg-Ag-Sm alloy was fabricated and subjected to single-stage aging and pre-aging(two-stage aging). Effect of pre-aging on micros tructure and mechanical properties of the alloy was investigated. It is found that the alloy is mainly composed of α-Al, Al_2Cu, Al_2CuMg and AlCu_4Sm. The number of plate-like Ω Al_2Cu precipitates is comparable to that of rod-like S Al_2 CuMg precipitates in the single-stage aged alloy, whereas, in the two-stage aged alloy, it is much higher than that of S precipitates. Q precipitates have a smaller plate thickness and distribute more uniformly in the two-stage aged alloy than in the single-stage aged *** tensile strength(UTS) and yield strength of the two-stage aged alloy are 12% higher than those of the single-stage aged one, indicating a better aging hardening caused by the two-stage aging. The increased tensile properties mainly come from both stronger precipitation strengthening caused by more Ω precipitates in the twostage aged alloy and stronger solution strengthening from Mg atoms. The fracture surfaces consist of both dimple zones composed of microscale dimples and platform zones composed of nanoscale dimples. The total area of dimple zones for single-stage aged alloy is much higher than that for two-stage aged alloy, which can be attributed to different numbers of Ω precipitates in the two alloys.

关键词： Rare earth aluminum alloy: Aging behavior Tensile property Fractography

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Salvianolic acid B protects the myelin sheath around injured spinal cord axons

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Neural Regeneration Research 2016年第3期11卷 487-492页

作者： Zhe Zhu Lu ding wen-feng Qiu hong-fu Wu Rui Li Hand & Foot Surgery and Reparative & Reconstruction Surgery Center the Second Hospital of Jilin University Department of Physiology Guangdong Medical University

Salvianolic acid B,an active pharmaceutical compound present in Salvia miltiorrhiza,exerts a neuroprotective effect in animal models of brain and spinal cord *** acid B can promote recovery of neurological function;however,its protective effect on the myelin sheath after spinal cord injury remains poorly ***,in this study,in vitro tests showed that salvianolic acid B contributed to oligodendrocyte precursor cell differentiation,and the most effective dose was 20 μg/m *** in vivo investigation,rats with spinal cord injury were intraperitoneally injected with 20 mg/kg salvianolic acid B for 8 *** amount of myelin sheath and the number of regenerating axons increased,neurological function recovered,and caspase-3 expression was decreased in the spinal cord of salvianolic acid B-treated animals compared with untreated control *** results indicate that salvianolic acid B can protect axons and the myelin sheath,and can promote the recovery of neurological *** mechanism of action is likely to be associated with inhibiting apoptosis and promoting the differentiation and maturation of oligodendrocyte precursor cells.

关键词： nerve regeneration spinal cord injury salvianolic acid B oligodendrocytes myelin sheath neural regeneration

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我们都是“同时代人”——如何建构当代文学价值共同体的反思

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当代文坛 2025年第1期 77-81页

作者：丁帆南京大学文学院

“同时代人”是一个超越年龄、时空的广义内涵的存在,它打破了生理年龄和朝代更迭,以代际划分的“同时代人”的陈见,用一种具有深刻和前瞻意义的理念,聚合成一种具有“当代性”的切分方法,以跨越代际的共同价值观来重塑“同时代人”群体... 详细信息

“同时代人”是一个超越年龄、时空的广义内涵的存在,它打破了生理年龄和朝代更迭,以代际划分的“同时代人”的陈见,用一种具有深刻和前瞻意义的理念,聚合成一种具有“当代性”的切分方法,以跨越代际的共同价值观来重塑“同时代人”群体,以此作为解决创作困囿和批评迷惘的突破口。“我们可以使自己成为这些文本的同时代人”的命题,才是需要正视的最本质的问题所在。当下的“同时代人”,既要以史为鉴,从历史的“同时代人”的思想宝库中,汲取属于我们这个时代的相对统一价值观,同时还要引领更多能够聚合在同一价值观下的“同时代人”,发出对整个世界的批判性哲学诘问,这也是改“未完成的现代性”为“当代性”关键词的理由,希冀由此而触及对当代文学治史观念的一种新观念和新方法,在“同时代人”旗帜下,建构起一种基本的人文价值观和学术守则。

关键词： “同时代人” “当代性” 文学价值共同体 “真理性”

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Temperature-Dependent ac Conductivity of the Fibonacci Lattice

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Chinese Physics Letters 1999年第7期16卷 529-531页

作者： ding Jian-wen YAN Xiao-hong FANG Xian-cheng Department of Physics Xiangtan UniversityXiangtan 411105 Institute of Solid State Physics Chinese Academy of SciencesHefei 230031

A new practical equation is derived from the Miller-Abrahams theory for different site-energies,and the temperaturedependent conductivity of Fibonacci lattice is calculated by a real-space renormalization-group *** is shown that there exist two types of temperature-dependent conductivity at low-and ***,it is found that the low-frequency conductivity oscillates dramatically with temperature.

关键词： temperature. Fibonacci conductivity

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Brazed joints of CBN grains and AISI 1045 steel with AgCuTi-TiC mixed powder as filler materials

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 717-724页

作者： wen-feng ding Jiu-hua Xu Zhen-zhen Chen hong-hua Su Yu-can Fu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The brazing process of cubic boron nitride （CBN） grains and AISI 1045 steel with AgCuTi-TiC mixed powder as a filler material was carried *** joining strength and the interfacial microstructure were *** experimental results indicate that the spreading of the molten filler material on AISI 1045 steel is decreased with the increase of TiC content.A good interface is formed between the TiC particulates and AgCuTi alloy through the wetting *** the case of AgCuTi＋16wt% TiC,the strength of the brazed steel-to-steel joints reached the highest value of 95MPa dependent upon the reinforcement effect of TiC particles within the filler *** resultants of TiB2,TiB,and TiN are produced at the interface of the CBN grains and the AgCuTi-TiC filler layer by virtue of the interdiffusion of B,N,and Ti atoms.

关键词： grinding wheels cubic boron nitride brazing filler metals shear strength interfaces

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EBD-YOLO：a lightweight auxiliary driving detection algorithm based on YOLOv5

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Optoelectronics Letters 2025年

作者： SUN Lianshuai SHI Tao ding Yao LI Song Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems， School of Electrical Engineer-ing and Automation， Tianjin University of Technology College of Electrical Engineering， North China University of Science and Technology

A lightweight road-assistant detection algorithm， EBD-YOLO， based on YOLOv5s is proposed to address the problems of high model complexity， computation cost， and difficulty in deployment on resource-limited embedded terminals in existing assisted driving detection algorithms. First， lightweight Transformer model EfficientViT was used as the backbone feature extraction network of YOLOv5s model to reduce network parameters and calculation costs. Secondly， a Focal-GIoU Loss function is proposed for bounding box regression to accelerate model convergence and reduce loss. Thirdly， the feature pyramid structure is improved to a weighted bi-directional feature pyramid network (BiFPN) to enhance localization and semantic features. Then， a dynamic head framework is added to unify the attention mechanism with the object detection head to improve its performance. Finally， a Soft-CIoU＿NMS algorithm is proposed in the post-processing stage to enhance occluded targets' localization and detection ability and reduce the missed detection rate. We conducted experiments on the KITTI and BDD100K datasets for autonomous driving， and the results showed that the EBD-YOLO model reduced in size by 38.4% and 37.2%， respectively. In comparison， the computational cost was reduced by 48.1%. As measured by mAP@0.5， the detection accuracy improved by 0.5% and 5.8%， respectively， and mAP@0.5:0.95 improved by 2.8% and 7%， respectively. These improvements satisfied the requirements for deployment on embedded terminals in cars.

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Compressive Strength and Interface Microstructure of PCBN Grains Brazed with High-Frequency Induction Heating Method

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Acta Metallurgica Sinica(English Letters) 2017年第7期30卷 641-649页

作者： Ye-Jun Zhu wen-Feng ding Ze-Yu Zhao Yu-Can Fu hong-Hua Su College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016China

In order to prepare monolayer brazed superabrasive wheels, the polycrystalline cubic boron nitride（PCBN）grains were brazed to AISI 1045 steel matrix with Ag–Cu–Ti filler alloy using the high-frequency induction heating technique. The compressive strengths of brazed grains were measured. Morphology, chemical composition and phase component of the brazing resultant around PCBN grain were also characterized. The results show that the maximum compressive strength of brazed grains is obtained in the case of brazing temperature of 965 °C, which does not decrease the original grain strength. Strong joining between Ag–Cu–Ti alloy and PCBN grains is dependent on the brazing resultants,such as TiB_2, TiN and AlTi_3, the formation mechanism of which is also discussed. Under the given experimental conditions, the optimum heating parameters were determined to be current magnitude of 24 A and scanning speed of0.5 mm/s. Finally, the brazing-induced residual tensile stress, which has a great influence on the grain fracture behavior in grinding, was determined through finite element analysis.

关键词： High-frequency induction brazing PCBN grain Compressive strength Interface microstructure Residual stress

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Stay Active to Cope with Fear: A Cortico-Intrathalamic Pathway for Conditioned Flight Behavior

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Neuroscience Bulletin 2019年第6期35卷 1116-1119页

作者： Ni Tang Yi-Fan ding wen Zhang Ji Hu Xiao-hong Xu School of Life Sciences and Technology ShangTech UniversityShanghai 201210China Institute of Neuroscience State Key Laboratory of NeuroscienceCAS Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai 200031China

When facing fear-provoking situations,animals and humans alternate between active and passive coping responses[1].Active coping such as flight or escape is thought to occur when animals perceive the situation to be **... 详细信息

关键词： Active freezing passive

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