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Stress-assisted corrosion mechanism of 3Ni steel by using gradient boosting decision tree machining learning method

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1311-1321页

作者： Xiaojia Yang Jinghuan Jia Qing Li Renzheng Zhu Jike Yang Zhiyong Liu Xuequn Cheng xiaogang Li Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China AECC Key Laboratory of Advanced Corrosion and Protection of Aeronautical Materials AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China

Traditional 3Ni weathering steel cannot completely meet the requirements for offshore engineering development,resulting in the design of novel 3Ni steel with the addition of microalloy elements such as Mn or Nb for strength enhancement becoming a *** stress-assisted corrosion behavior of a novel designed high-strength 3Ni steel was investigated in the current study using the corrosion big data *** information on the corrosion process was recorded using the galvanic corrosion current monitoring *** gradi-ent boosting decision tree(GBDT)machine learning method was used to mine the corrosion mechanism,and the importance of the struc-ture factor was *** exposure tests were conducted to verify the calculated results using the GBDT *** indic-ated that the GBDT method can be effectively used to study the influence of structural factors on the corrosion process of 3Ni ***-ferent mechanisms for the addition of Mn and Cu to the stress-assisted corrosion of 3Ni steel suggested that Mn and Cu have no obvious effect on the corrosion rate of non-stressed 3Ni steel during the early stage of *** the corrosion reached a stable state,the in-crease in Mn element content increased the corrosion rate of 3Ni steel,while Cu reduced this *** the presence of stress,the increase in Mn element content and Cu addition can inhibit the corrosion *** corrosion law of outdoor-exposed 3Ni steel is consistent with the law based on corrosion big data technology,verifying the reliability of the big data evaluation method and data prediction model selection.

关键词： weathering steel stress-assisted corrosion gradient boosting decision tree machining learning

Modified Sadowski formula-based model for the slope shape amplification effect under multistage slope blasting vibration

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International Journal of Mining Science and Technology 2024年第5期34卷 631-641页

作者： xiaogang Wu Mingyang Wang Hao Lu Yongjun Zhang Wen Nie State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China State Key Laboratory of Metal Mine Safety and health Ma’anshan 243000China School of Civil Engineering Qingdao University of TechnologyQingdao 266520China

Blasting operations,which are crucial to open-pit mine production due to their simplicity and efficiency,require precise control through accurate vibration velocity *** conventional Sadowski formula mainly focuses on blast center distance but neglects the amplification effect of blasting vibration waves by terraced terrain,from which the calculated blasting vibration velocities are smaller than the actual values,affecting the safety of the *** address this issue,our model introduces the influences of slope and time into Sadowski formula to measure safety through blast vibration *** the northern section of the open-pit quartz mine in Jinchang City,Gansu Province,China,the data of a continuous blasting slope project are referred *** findings reveal a noticeable vibration amplification effect during blasting when a multi-stage slope platform undergoes a sudden cross-sectional change near the upper overhanging *** amplification vibration coefficient increases with height,while vibration waves within rocks decrease from bottom to ***,platforms without distinct crosssectional changes exhibit no pronounced amplification during *** addition,the vibration intensity decreases with distance as the rock height difference change *** results obtained by the proposed blast vibration displacement equation incorporating slope shape influence closely agree with real-world *** to Pearson correlation coefficient(PPMCC)analysis,the average accuracy rate of our model is 88.84%,which exceeds the conventional Sadowski formula(46.92%).

关键词： Multistage slope Slope shape influence factor Continuous blasting Sadowski formula Amplification effect

增值税不完全退税与出口企业纵向一体化:基于非税收中性的视角

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财贸经济 2023年第9期44卷 143-158页

作者：何小钢沈立锦毛海涛江西财经大学应用经济学院 330013 中南财经政法大学工商管理学院 430073

内外贸一体化是推进贸易强国的重要任务。增值税出口不完全退税打破了税收中性,有碍于内外贸的公平发展,进而不利于产品在国内市场的流动和专业化分工。本文利用2000—2006年出口企业数据,首次度量了不完全退税下企业层面的“出口增值税... 详细信息

内外贸一体化是推进贸易强国的重要任务。增值税出口不完全退税打破了税收中性,有碍于内外贸的公平发展,进而不利于产品在国内市场的流动和专业化分工。本文利用2000—2006年出口企业数据,首次度量了不完全退税下企业层面的“出口增值税”,研究了不完全退税对出口企业纵向一体化的影响,研究结果如下。(1)不完全退税打破了税收中性,进而增加了交易成本,改变了分工决策,促使出口企业提高纵向一体化程度。(2)异质性分析表明,在企业层面,不完全退税的一体化效应在非国有控股或国有股权占比低于34%、出口密度高,以及规模大、融资约束低而有能力实施一体化的企业中更为显著;在地区层面,在市场分割程度高、产品市场发育程度低的地区上述效应更加显著。(3)在不完全退税下出口企业的纵向一体化提高了企业盈利能力,但是降低了企业生产效率。本文丰富和拓展了企业生产组织决策的税制诱因,从维护税收中性的角度为促进内外贸一体化发展提供了重要参考。

关键词：不完全退税交易成本税收中性纵向一体化

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从肃北五个庙看敦煌西夏石窟艺术的谱系——五个庙石窟研究之二

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敦煌研究 2024年第4期 73-85页

作者：张小刚敦煌研究院考古研究所

肃北五个庙石窟的西夏壁画在敦煌石窟艺术中颇具特色。以五个庙西夏壁画为纽带，可以更加清楚地看到敦煌石窟西夏壁画艺术发展演变的过程和西夏时期敦煌地区各个石窟群之间相互影响的密切关系，为构建完整的敦煌西夏石窟艺术的谱系填补... 详细信息

肃北五个庙石窟的西夏壁画在敦煌石窟艺术中颇具特色。以五个庙西夏壁画为纽带，可以更加清楚地看到敦煌石窟西夏壁画艺术发展演变的过程和西夏时期敦煌地区各个石窟群之间相互影响的密切关系，为构建完整的敦煌西夏石窟艺术的谱系填补了重要缺环。

关键词：肃北五个庙石窟敦煌石窟西夏时期壁画

Simulation of gas-solids heat transfer in cyclone pyrolyzer using CFD-DEM model

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Particuology 2024年第2期85卷 155-166页

作者： Nan Zhang Xueer Pan Jingxuan Yang Qian Liu Wenhao Lian Xiao Du Zhonglin Zhang xiaogang Hao Guoqing Guan College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan030024China School of Chemistry and Chemical Engineering North University of ChinaTaiyuan030051China Shanxi Jinke Technology Service Company Limited Taiyuan030000China Labraory of Eey onveron Engineerng Institute f Rgional Innvation(RI)Hosaki Univerty3-BunkychoHiroak036-8561Japan

Fast heat transfer in the pyrolyzer can increase the yield of pyrolysis gas and tar,and improve the quality of *** with the downer pyrolyzer,the cyclone pyrolyzer can simultaneously achieve high solids holdup and violent turbulence,and correspondingly faster heat *** this work,the heat transfer behavior in the cyclone pyrolyzer is specifically studied using the computational fluid dynamics-discrete element *** simulation results reveal that the gas-solids heat convection contributes mainly to the heat transfer process,and the heat radiation and conduction are relatively small and almost negligible,*** with the downer pyrolyzer under the same operating conditions,the heating rate is significantly increased in the cyclone *** analyzing the flow characteristics in the cyclone pyrolyzer,it is found that the region of high convective heat transfer rate coincides with that of natural cyclone ***,the final coal temperature increases with the increase of gas velocity and exists a maximum *** results can offer some qualitative understanding of the heat transfer behavior in the cyclone pyrolyzer.

关键词： Cyclone pyrolyzer Rapidly heating heat convection Natural cyclone length CFD-DEM

Exclusive Hypothesis Testing for Cox's Proportional Hazards Model

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Journal of Systems Science & Complexity 2024年第5期37卷 2157-2172页

作者： WU Qiang TONG Xingwei DUAN xiaogang School of Statistics Beijing Normal University

Exclusive hypothesis testing is a new and special class of hypothesis testing. This kind of testing can be applied in survival analysis to understand the association between genomics information and clinical information about the survival time. Besides, it is well known that Cox's proportional hazards model is the most commonly used model for regression analysis of failure time. In this paper,the authors consider doing the exclusive hypothesis testing for Cox's proportional hazards model with right-censored data. The authors propose the comprehensive test statistics to make decision, and show that the corresponding decision rule can control the asymptotic Type Ⅰ errors and have good powers in theory. The numerical studies indicate that the proposed approach works well for practical situations and it is applied to a set of real data arising from Rotterdam Breast Cancer Data study that motivated this study.

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Sharper Hardy Uncertainty Relations on Signal Concentration in Terms of Linear Canonical Transform

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Chinese Journal of Electronics 2024年

作者： xiaogang XU Guanlei XU Xiaotong WANG College of Computer and Information Engineering Zhejiang Gongshang University

Linear canonical transform is of much significance to optics and information science. Hardy uncertainty principle, like heisenberg uncertainty principle, plays an important role in various fields. In this paper, four new sharper Hardy uncertainty relations on linear canonical transform are derived. These new derived uncertainty relations are connected with the linear canonical transform parameters and indicate new insights for signal energy concentration. Especially, for certain transform parameters, e.g. b=0, these new proposed uncertainty relations break the traditional counterparts in signal energy concentration, as will result in new physical interpretation in terms of uncertainty principle. Theoretical analysis and numerical examples are given to show the efficiency of these new relations.

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Enhancing multifunctional photocatalysis with acetate-assisted cesium doping and unlocking the potential of Z-scheme solar water splitting

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Carbon Energy 2024年第3期6卷 178-195页

作者： Mengmeng Ma Jingzhen Li xiaogang Zhu Kong Liu Kaige Huang Guodong Yuan Shizhong Yue Zhijie Wang Shengchun Qu Key Laboratory of Semiconductor Materials Science Beijing Key Laboratory of Low Dimensional Semiconductor Materials and DevicesInstitute of SemiconductorsChinese Academy of SciencesBeijingChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamenChina State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijingChina

Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most ***,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make *** this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy *** optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(heR)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an *** penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are *** atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic ***,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible heR yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN *** work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.

关键词： acetate-assisted cesium doping multifunctional photocatalysis Z-scheme

技术市场赋能地方创业活力——来自中国省级地区的经验证据

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经济问题探索 2022年第10期 53-76页

作者：肖小虹彭金霞贺小刚贵州财经大学工商管理学院贵阳550025 上海财经大学商学院上海200433 上海财经大学浙江学院浙江金华321000

创业在拉动经济增长、实现社会和环境包容性发展中发挥着重要的作用,但对于创业活力到底受制于何种因素仍是一个有待探讨的学术问题。本文探讨了技术市场对创业活力的影响及其背后的机制,基于2005—2019年中国30个省级地区的面板数据进... 详细信息

创业在拉动经济增长、实现社会和环境包容性发展中发挥着重要的作用,但对于创业活力到底受制于何种因素仍是一个有待探讨的学术问题。本文探讨了技术市场对创业活力的影响及其背后的机制,基于2005—2019年中国30个省级地区的面板数据进行了实证分析。主要得到以下结论:技术市场的活跃度能显著地提高当地的创业活力,并通过了工具变量法等一系列稳健性检验,且在文化包容性更高的省份及知识产权保护下这一影响更强;地方政府的创新驱动政策显著地改进了技术市场对创业活力的积极作用,尤其是在国家创新驱动政策实施后,此积极效应表现得更为突出;技术市场交易活跃度之所以促进了创业活力,其关键在于活跃的技术市场所带来的科技人才流动的中介传导效应。本文进一步研究发现,技术市场集聚对地方创业活力产生了放大效应,且沿海地区的技术市场聚集对创业活力所产生的积极作用将显著高于内陆地区。本文的研究为理解地方创业活力的形成机制提供了新的研究视角,也为创业创新政策的制定提供了理论支撑。

关键词：技术市场地方创业活力创新驱动政策科技人才流动技术市场集聚