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地方性金融机构优化了金融资源配置吗?——来自城市商业银行设立的证据

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浙江大学学报（人文社会科学版） 2024年第1期54卷 61-79页

作者：金雪军施云辉吴鹏浙江大学经济学院浙江杭州310058 浙江财经大学经济学院浙江杭州310018

以城市商业银行为代表的地方性金融机构在促进地区经济增长和金融市场发展的同时,也会对地区内金融资源配置的模式和效率产生重要影响。实证研究发现:(1)城市商业银行的设立加剧了地区金融资源错配程度,且这一影响在中部、西部城市和资... 详细信息

以城市商业银行为代表的地方性金融机构在促进地区经济增长和金融市场发展的同时,也会对地区内金融资源配置的模式和效率产生重要影响。实证研究发现:(1)城市商业银行的设立加剧了地区金融资源错配程度,且这一影响在中部、西部城市和资本依赖型行业中更显著;(2)城市商业银行的设立增加了地区内企业的信贷可得性,但也使更多的信贷资源流向了回报率较低的国有企业,造成地区金融资源分配的非理性化;(3)城市商业银行的设立对地区金融资源配置效率的负面影响会随着地方政府干预的减少而被弱化。上述结论为促进我国地方性金融机构的发展和提升地区金融资源配置效率提供了重要的理论和实证经验。

关键词：地方性金融机构城市商业银行金融资源错配地方政府干预

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Microstructure and Mechanical Properties of 50SiMnNiNb Steel by a Novel Quenching-Partitioning-Austempering Heat Treatment

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 645-650页

作者： LI Hongyan jin xuejun School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

For the purpose of reducing weight of steel parts, save raw materials and keep or even improve safety standards, the development of advanced high strength steels is increasingly demanded in the automotive industry and engineering applications. We have proposed a novel heat treatment （quenching-partitioning-austempering treatment, Q-P-A） to obtain steel parts with high strength and good ductility. The Q-P-A process is intended to produce microstructure consisted of carbon-depleted martensite, carbon-enriched retained austenite and nanostructured bainite. Quenching（Q） treatment fabricates mixed microstructure of carbon-supersaturated martensite and certain amounts of untransformed austenite. Partitioning（P） thermal treatment accomplishes fully diffusing of carbon from the supersaturated martensite phase to the untransformed austenite phase and enriching the amount of carbon in untransformed austenite. Further low-temperature austempering（A） process induces incredible thin bainite from the carbon-enriched untransformed austenite. A study of the microstructure and mechanical properties of 50SiMnNiNb steel subjected to the novel Q-P-A treatment is presented. Microstructure is assessed by optical microscope（OM）, field emission scanning electron microscope（FESEM） and transmission electron microscope（TEM）, and the corresponding mechanical properties are measured. The experimental results indicate that attractive mechanical properties of steels during the Q-P-A process are attributed to the complex multi-phase structure. Slender plates of bainite with 20-40 nm thick are generated in the medium carbon steel. Meanwhile, with increasing of the volume fraction of nanostructured bainite, yield strength of steel parts is increased with little degradation of ultimate tensile strength. In this paper, a novel quenching-partitioning-austempering heat treatment is proposed, and the attractive mechanical properties of steels are obtained during the Q-P-A process.

关键词： heat treatment quenching-partitioning-austempering martensite retained austenite nanostructured bainite

Secondary Austenite Morphologies in Fusion Zone of Welded Joint after Postweld Heat Treatment with a Continuous Wave Laser

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Journal of Materials Science & Technology 2012年第3期28卷 249-254页

作者： Heping Liu xuejun jin School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

In order to improve the weldability of duplex stainless steels,obtaining more secondary austenite in the weld metal is an effective ***,optimizing the secondary austenite by changing its morphology,volume fraction and stability may be expected to enhance the ductility of the *** secondary austenite morphologies in the fusion zone of the laser continuously heat treated welds of 2205 duplex stainless steel were *** secondary austenite morphologies were found to be influenced by different laser power *** secondary austenite with penniform,freely grown and dendritic shape appeared in the course of 4,6 and 8 kW continuous heat treatment,*** was found that there were three kinds of morphologies of secondary austenite in the fusion zone treated by different power,i.e.,widmannst¨atten austenite,grain boundary austenite and intragranular *** results demonstrated that the mechanism of the secondary austenite formation was a displacement mechanism during the initial austenite lath formation and a diffusion mechanism during *** nitrides provided the nitrogen for the transformation and at the same time acted as nucleation sites for the secondary austenite.

关键词： Secondary austenite morphology CO2 laser weld Continuous heat treatment

长三角地区二重开放与能源生态效率时空格局及关联性研究

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区域经济评论 2024年第3期 135-144页

作者：童素娟赵俊威金雪军浙江科技大学经济与管理学院杭州310023 浙江大学经济学院杭州310058 浙江省机电技师学院义乌322000

如何形成更高层次的国际开放格局和更切实有效的国内开放格局,实现资源节约、绿色低碳与经济发展共赢,已成为长三角地区高质量和可持续发展的重要命题。基于2011-2021年长三角地区41个城市的面板数据,探究二重开放和能源生态效率的时空... 详细信息

如何形成更高层次的国际开放格局和更切实有效的国内开放格局,实现资源节约、绿色低碳与经济发展共赢,已成为长三角地区高质量和可持续发展的重要命题。基于2011-2021年长三角地区41个城市的面板数据,探究二重开放和能源生态效率的时空格局及关联性,结果表明:第一,国际开放度整体上呈先下降后平稳趋势,区际开放度呈M型演变特征,能源生态效率呈“上升-平稳”的时序演变趋势。第二,能源生态效率呈现出上海>江苏>浙江>安徽的格局分布特征,主要表现为逐级改变特征,且具有显著的空间指向特征。第三,国际开放与能源生态效率之间存在U型关系,区际开放对能源生态效率具有显著正向促进作用,二重开放存在互补和溢出效应。

关键词：二重开放能源生态效率 SBM模型空间计量模型

Atom Probe and Mssbauer Spectroscopy Investigations of Cementite Dissolution in a Cold Drawn Eutectoid Steel

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Journal of Materials Science & Technology 2010年第9期26卷 776-782页

作者： Na Min Wei Li Hongyan Li xuejun jin School of Materials Science an-d Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Mssbauer spectrum and three dimensional atom probes（3DAP） were combined to investigate the mechanism of cementite dissolution in a cold-drawn eutectoid steel at a true strain of *** experimental results suggest that the dislocations play an important role in the dissolution of the cementite by sweeping across the nano-scaled cementite,and transferring carbon from cementite to ferrite inducing cementite *** mechanism of cementite dissolution in the steel is discussed in association with the investigation of nonstoichiometric cementite structure after heavy deformation.

关键词： Eutectoid steel Cementite Three dimensional atoms probe Mssbauer spectrum

基于Pix2pix模型的继电器动作状态识别方法研究

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铁道通信信号 2024年第8期60卷 16-21页

作者：李永燕叶伟金雪军上海铁大电信科技股份有限公司上海200070

为解决采用深度学习算法识别信号继电器组合动作状态时难以获取大量高质量标注数据的问题,利用Pix2pix模型小样本学习能力强的优点,研究基于Pix2pix算法模型的继电器动作状态识别方法。首先,使用labelimg图像标注软件对继电器组合图像... 详细信息

为解决采用深度学习算法识别信号继电器组合动作状态时难以获取大量高质量标注数据的问题,利用Pix2pix模型小样本学习能力强的优点,研究基于Pix2pix算法模型的继电器动作状态识别方法。首先,使用labelimg图像标注软件对继电器组合图像进行标注,根据标注信息对继电器组合图像进行处理,得到与继电器组合图像对应的标注图像数据集;其次,划分数据集并对训练集进行数据增强处理,并训练Pix2pix网络得到生成器,使用Pix2pix模型的生成器对继电器组合进行图像转译得到生成图像;然后,使用图像后处理技术对生成图进行分析,得到继电器位置和状态属性信息;最后,通过测试集对该算法进行试验验证,得到继电器动作状态识别的准确率达到94%。试验结果表明,使用Pix2pix模型对信号继电器组合进行图像转译具有可行性和有效性。

关键词：继电器组合图像转译深度学习准确率 Pix2pix模型

Does communication increase investors’trading frequency?Evidence from a Chinese social trading platform

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Financial Innovation 2022年第1期8卷 1864-1895页

作者： xuejun jin Jiawei Yu School of Economics Zhejiang University866 Yuhangtang RoadHangzhouChina

This study examines the impact of communication on investors’trading frequency based on a unique dataset drawn from a Chinese social trading *** find robust evidence that real-account portfolio owners on the platform trade more frequently under the influence of the comments posted by their leaders(the owners of portfolios they have followed).Moreover,portfolio owners are more sensitive to the quantity than to the tone of leaders’***,both trading frequency and leaders’comments negatively impact portfolio owners’future *** find-ings support the notion that social interaction promotes active investment strategies.

关键词： Communication Social interaction Social trading platform Trading frequency

Flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

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Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： Yichao jin Kun WU xuejun FAN Institute of Applied Physics and Computational Mathematics Beijing 100094China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and Flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons Flow instability Flow maldistribution Density-wave oscillations

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增材制造高强钢中的马氏体组织与马氏体相变

钢铁 2024年第6期59卷 83-93,154页

作者：汤隽劼喻异双胡斌熊智慧刘仕龙金学军上海交通大学材料科学与工程学院上海200240 上海交通大学生物医学工程学院上海200240

马氏体组织因其与多种强化机制兼容,是高强钢追求极致强塑匹配的理想组织。传统马氏体组织以板条或针状结构为主,而对于采用金属增材制造技术加工的高强钢而言,极快的冷却速率、循环热输入和扫描式的加工模式决定了其组织的非平衡性,高... 详细信息

马氏体组织因其与多种强化机制兼容,是高强钢追求极致强塑匹配的理想组织。传统马氏体组织以板条或针状结构为主,而对于采用金属增材制造技术加工的高强钢而言,极快的冷却速率、循环热输入和扫描式的加工模式决定了其组织的非平衡性,高能热输入引入的胞结构、元素偏聚、位错塞积及原奥氏体母相组织均区别于传统高强钢。这些与传统减材加工的区别给增材制造高强钢的性能调控和组织强韧化带来了全新挑战,常规后处理工艺与增材高强钢适配性差,亟需依据增材高强钢的微观组织和马氏体相变特点设计更合适的强韧化组织和后处理路线。简析了金属增材制造技术的发展脉络及当前面临的强塑性、强韧性制约瓶颈,归纳了增材制造高强钢中多层级马氏体组织与板条等传统马氏体组织相比所具有的多组元、亚稳态、多尺度特点,以金属增材加工涉及的两个相变过程(凝固和马氏体相变)切入,从高冷速、循环热输入的工艺特点和化学成分梯度、位错分布、母相组织等微观特征阐释这些组织和性能差异性的成因,归纳了成分、热处理、组织设计等对增材高强钢进行改性和强韧化的可行方法,最后总结了当前增材制造高强钢中的马氏体组织研究进展与热点方向,为日后增材制造马氏体高强钢的发展与推广提供借鉴及指导。

关键词：金属增材制造先进高强钢马氏体相变微观组织设计力学性能调控