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The Same Distribution of Limit Cycles in a Hamiltonian System with Nine Seven-order Perturbed Terms

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Acta Mathematicae Applicatae Sinica 2008年第1期24卷 167-176页

作者： Tao Jiang zhi-yan yang School of Information Beijing Wuzi University Beijing 101149 China

Using qualitative analysis and numerical simulation, we investigate the number and distribution of limit cycles for a cubic Hamiltonian system with nine different seven-order perturbed terms. It is showed that these perturbed systems have the same distribution of limit cycles. Furthermore, these systems have 13, 11 and 9 limit cycles for some parameters, respectively. The accurate positions of the 13, 11 and 9 limit cycles are obtained by numerical exploration, respectively. Our results imply that these perturbed systems are equivalent in the sense of distribution of limit cycles. This is useful for studying limit cycles of perturbed systems.

关键词： Limit cycles bifurcation

Some Inequalities and Limit Theorems Under Sublinear Expectations

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 451-462页

作者： Ze-Chun HU yan-zhi yang College of Mathematics Sichuan University Department of Mathematics Nanjigng University

In this note, we study inequality and limit theory under sublinear expectations. We mainly prove Doob＇s inequality for submartingale and Kolmogrov＇s inequality. By Kolmogrov＇s inequality, we obtain a special version of Kolmogrov＇s law of large numbers. Finally, we present a strong law of large numbers for independent and identically distributed random variables under one-order type moment condition.

关键词： sublinear expectation inequality the law of large numbers submartingale

Creation of Air-Cooled Mn Series Bainitic Steels

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Journal of Iron and Steel Research International 2008年第6期15卷 1-9页

作者： FANG Hong-sheng FENG Chun ZHENG yan-kang yang zhi-gang BAI Bing-zhe Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

The development and mechanical performances of new type air-cooled Mn series bainitic steels including granular bainitic steels, FGBA/BG duplex steels, CFB/M duplex steels, medium carbon bainite/martensite steels, cast bainitic steels invented by the authors are summarized. The novel series of bainitic steels are alloyed with Mn, and several series bainitic duplex microstructures can be easily obtained under the condition of air cooling through unique composition design. The invented idea, the principle of alloying design, the strengthening mechanism, and the evolution of the microstructure of new type air cooled Mn series bainitic steels are presented. Furthermore, the applications in different fields of these Mn series air cooled bainitic steels with different strength level are also introduced. It is suggested that the significance of the development of the air cooled Mn series bainitic steel can be summarized as follows： reducing costs of both raw materials and production; good combination of strength and toughness; self-hardening with high bainitic hardenahility by air cooling from hot working without additional quenching-tempering treatment or quenching procedure; large savings in energy resources; and reduced environmental pollution.

关键词： bainite bainitic steel microstructure mechanical property air cooling

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联合谱域与深度域光谱相位显微方法

物理学报 2013年第16期62卷 167-173页

作者：颜扬治丁志华王玲沈毅浙江大学现代光学仪器国家重点实验室杭州310027 杭州电子科技大学生命信息与仪器工程学院杭州310018

提出了一种联合谱域与深度域光谱相位显微方法,该方法利用谱域相位信息克服2π歧义,并结合深度域相位信息,以实现高动态范围、高灵敏度的相位检测.首先通过理论推导和信号模拟,进行了深度域相位和谱域相位的灵敏度比较,证明了深度域相... 详细信息

提出了一种联合谱域与深度域光谱相位显微方法,该方法利用谱域相位信息克服2π歧义,并结合深度域相位信息,以实现高动态范围、高灵敏度的相位检测.首先通过理论推导和信号模拟,进行了深度域相位和谱域相位的灵敏度比较,证明了深度域相位在灵敏度上要高于谱域相位.进而详细介绍了联合谱域与深度域光谱相位显微方法.最后通过盖玻片和光学分辨率板实验验证了所提出的联合谱域与深度域光谱相位显微方法能够在实现高动态测量范围的同时保持高相位灵敏度.

关键词：光谱相位显微方法动态范围灵敏度

Development of New Type Mn-Series Bainitic Steels in China

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Journal of Iron and Steel Research International 2011年第S1期18卷 112-120页

作者： BAI Bing-zhe,GAO Gu-hui,ZHENG yan-kang,yang zhi-gang (Key Laboratory of Advanced Materials of Ministry of Education,Department of Material Science and Engineering,Tsinghua University,Beijing 100084,China) Tsinghua Univ Dept Mat Sci & Engn Minist Educ Key Lab Adv Mat Beijing 100084 Peoples R China

The alloying design idea,strengthening-toughening mechanism,microstructure,mechanical performances,development and application in China of new type Mn-series bainitic steels are ***-series air-cooling bainitic steels including granular bainitic steels,FGBA /BG duplex steels,CFB/M duplex steels,medium carbon bainite/martensite steels,cast bainitic steels are *** invented idea mechanical performances,development and application of second generation of Mn-series bainitic steels,*** quenching Mn-series bainitic steels invented by the authors newly are *** water quenching Mn-series bainitic steels cover severe series steels containing ultra-low carbon,low-low carbon,medium-low carbon,and high-low carbon content etc,which can reduce the amount of alloying content,increase hardening capability and improve *** should be pointed out that the application of both air cooling and water quenching Mn-series bainitic steels are complementary and mutually reinforcing,and the new type Mn-series bainitic steels can meet the performance requirements of most steels used in engineering *** newest technologies of Mn-series bainitic steels in China are discussed in this *** is suggested that the significance of the development of the Mn-series bainitic steels can be summarized as:significantly reducing costs of both raw materials and production;good combination of strength and toughness;excellent weldability;simple procedure;large savings in energy resources and reduced environmental pollution.

关键词： bainitic steels strengthening-toughening mechanism low cost,high performances air cooling bainitic steel water quenching bainitic steel

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敞口式离心喷嘴内部及近喷口区域的流动特性

航空动力学报 2016年第12期31卷 2988-2995页

作者：陈晨杨样高宏力晏至辉杨顺华西南交通大学机械工程学院成都610031 中国空气动力研究与发展中心吸气式高超声速技术研究中心四川绵阳621000

为了深入理解敞口式离心喷嘴雾化机制,基于界面追踪法VOF(volume of fluid)和RNG(renormalization group)湍流模型对敞口式离心喷嘴进行数值模拟,计算结果与PDPA(phase Doppler particle analyzer)及单反相机测得的喷嘴出口速度和雾化... 详细信息

为了深入理解敞口式离心喷嘴雾化机制,基于界面追踪法VOF(volume of fluid)和RNG(renormalization group)湍流模型对敞口式离心喷嘴进行数值模拟,计算结果与PDPA(phase Doppler particle analyzer)及单反相机测得的喷嘴出口速度和雾化锥角一致性较高.清晰地捕获了中心空气涡结构及喷嘴内部的回流区,展现了切向孔与旋流室的交互影响,并着重分析了液膜厚度演变特性及喷嘴内外速度场发展规律.随着喷注压降的增加,破碎长度降低,打开长度及喷雾角增加.揭示了敞口式离心喷嘴独特的流动机制,为喷嘴雾化性能预测及结构优化提供依据.

关键词： VOF模型内部流动空气涡敞口式离心喷嘴雾化

Study of One Rainstorm Being Affected by Two Weather Systems in Jinzhou Area

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Meteorological and Environmental Research 2011年第4期2卷 30-32,38页

作者： yan zhi-yu, yang Gui-juan Jinzhou Meteorological Bureau of Liaoning Province, Jinzhou 121001, China

[Objective] The aim was to study one rainstorm process being affected by two weather system. [Method] Influenced by high trough and Mongolia cold front, high latitude trough and subtropical high shear, rainstorm occurred in Jinzhou from October 19 to 22 in 2010. In order to make the analysis clear, there were two precipitation stages. Considering precipitation, weather situation, satellite image and numerical forecast, the rainstorm process was discussed. [Result] There were two raining stages during this precipitation. The first stage was affected by high altitude trough and ground Mongolia cold front, and the last stage was influenced by high altitude trough and subtropical high shear;the high latitude air, low latitude shear,low air torrent,subtropical high and their mutual coupling effect were the main influencing system and cause for this rainstorm. Satellite image suggested that there was convective cloud developing,weakening, disappearing and regenerating around the convective cloud of water vapor passage, showing distinct train operation state. The strengthening and weakening cloud image fitted the real precipitation. Numerical forecast precisely predicted the upper air and ground situation of the generation of rainstorm, especially the report of the east-retreating and south-falling trend of subtropical high;European center forecast fitted reality. There was certain error in predicting T639. Precipitation forecast was fine. [Conclusion] The study provided basis for the meteorological service work in future.

关键词： Influencing system Rainstorm Process analysis Jinzhou area China

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企业技术能力对外部技术利用的影响

管理评论 2017年第7期29卷 46-60页

作者：闫泽斌杨治周南华中科技大学管理学院香港城市大学商学院

本文研究了企业技术能力与外部技术利用的关系,综合吸收能力和组织惯性两种理论视角,本文认为企业技术能力与其外部技术利用呈倒U型关系,而非先前研究中所假定的线性关系。来自1231家中国制造业企业的实证研究表明:(1)随着技术能力的增... 详细信息

本文研究了企业技术能力与外部技术利用的关系,综合吸收能力和组织惯性两种理论视角,本文认为企业技术能力与其外部技术利用呈倒U型关系,而非先前研究中所假定的线性关系。来自1231家中国制造业企业的实证研究表明:(1)随着技术能力的增长,技术能力对企业的外部技术利用产生正向影响;但当技术能力达到一定高度后,技术能力的进一步增长则会负向影响企业的外部技术利用;(2)在技术能力增长的过程中,较高技术环境不确定和政策环境不确定使上述的倒U关系变平缓。另外,我们的实证结果进一步显示,稳定的政策环境有利于促进技术能力产生较高的外部技术利用水平。

关键词：技术能力外部技术利用技术环境不确定政策环境不确定

Shallow Analysis on the First Spring Soaking Rain Weather and Its Precipitation Enhancement Potential Forecast in Jinzhou Area in 2010

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Meteorological and Environmental Research 2011年第4期2卷 42-46页

作者： LI Zhuo-li, yan zhi-yu, yang Gui-juan Jinzhou Meteorological Bureau in Liaoning Province, Jinzhou 121000, China

[Objective] The research aimed to study the first spring soaking rain weather and its precipitation enhancement potential forecast in Jinzhou area in 2010. [Method] From the weather situation characteristics, main influence system, forecast service, artificial precipitation enhancement operation and so on, the first spring soaking rain weather process in Jinzhou area in 2010 was summarized comprehensively. [Result] The weather situation characteristics of soaking rain were that the high-altitude cold air was weak, and the low-level warm wet airflow was obvious. The main influence systems were the high-altitude trough, the high-altitude shear line and the ground Mongolian cyclone. The ground inverted trough system advanced northward and got through with the same phase of Mongolian cyclone, which provided the certain energy and water vapor for the precipitation in Jinzhou area. It was one of key reasons for generating the soaking rain. The numerical forecast product played the certain guidance role in the forecast service work. The situation field forecast was accurate, but the precipitation forecast deviation was big. Therefore, the forecast service couldn’t depend on the numerical forecast product simply and totally, and should combine with the actual monitoring data to analyze and apply comprehensively. [Conclusion] The research played the safeguarding role in carrying out the large-scale artificial precipitation enhancement operation successfully in the whole area of Jinzhou.

关键词： Spring soaking rain Weather situation Precipitation enhancement potential Forecast service Jinzhou area China