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连铸过程长水口理论吹氩流量分析

中国冶金 2024年第3期34卷 75-83页

作者：张育萌程树森冯永平李积鹏北京科技大学冶金与生态工程学院北京100083 酒钢集团宏兴钢铁股份有限公司碳钢薄板厂甘肃嘉峪关735100

连铸过程水口间接缝容易吸入空气,使得钢液二次氧化。生产中采用长水口吹氩来防止空气吸入,但吹氩流量控制不当会导致铸坯缺陷。水口吸入空气是由于水口内部压力低于大气压,目前水口吹氩流量控制与工艺参数调整并未建立联系。基于连续... 详细信息

连铸过程水口间接缝容易吸入空气,使得钢液二次氧化。生产中采用长水口吹氩来防止空气吸入,但吹氩流量控制不当会导致铸坯缺陷。水口吸入空气是由于水口内部压力低于大气压,目前水口吹氩流量控制与工艺参数调整并未建立联系。基于连续性方程和伯努利方程建立钢包到中间包的质量-能量守恒数学物理模型,研究长水口钢液流动时水口内压力分布,总结不同出口条件及吹氩流量下水口内流体分布状态,同时计算不同条件下的理论吹氩流量;探究浇注时间、拉坯速度、滑动水口及长水口直径、长水口浸入深度、吹氩流量对水口内压力分布的影响。研究发现,提高拉速、增加长水口浸入深度、减小滑动水口和长水口直径以及提高水口吹氩流量有利于减小水口内负压;当提高拉速、增加长水口浸入深度或增大水口直径时应当加大吹氩流量;使用喇叭型长水口可以降低出口钢液速度,其内部压力小于直筒型长水口,吹氩时其水口出口钢液速度增加量比直筒型长水口小。研究结果为制定长水口吹氩量提供了理论基础。

关键词：长水口伯努利方程连续性方程压力分布吹氩流量

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一道二重积分的多种异向思维解法探讨

高等数学研究 2024年第2期27卷 55-58页

作者：邓明香冯永平广州大学数学与信息科学学院广东广州510006

本文针对2022年全国硕士研究生入学考试试题中一道二重积分问题,探讨了运用Green公式、极坐标变换、对称性、挖补思想、区域可加性等多种计算方法,并给出了相应的分析过程及解答.

关键词：二重积分极坐标变化累次积分

The twoscale asymptotic error analysis for piezoelectric problems in the quasi-periodic structure

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Science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1844-1853页

作者： feng yongping DENG MingXiang GUAN XiaoFei School of Mathematics and Information Sciences Key Laboratory of Mathematics and Interdisciplinary Sciences of Guangdong Higher Education Institutes Guangzhou University Guangzhou 510006 China Department of Mathematics University of California San Diego 92093 USA Department of Mathematics Tongji University Shanghai 200092 China

Applications for piezoelectric effect have grown rapidly, and piezoelectric materials play important roles in countless areas of modem life. By means of twoscale method and coupled boundary layer, some new kinds of twoscale asymptotic expansions for solutions to the electrical potential and the displacement in quasi-periodic structure under coupled piezoelectric effect are derived, and the homogenization constants of piezoelectric materials are presented. The coupled twoscale relation between the electrical potential and the displacement is set up, and some improved asymptotic error estimates are analyzed.

关键词： twoscale method piezoelectricity quasi-periodic structure homogenization constants

Programmable curvilinear self-propelling of droplets without preset channels

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Droplet 2024年第4期3卷 21-28页

作者： Shile feng yongping Hou Yongmei Zheng Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education Institution of ChemistryBeihang University(BUAA)BeijingChina State Key Laboratory of High-performance Precision Manufacturing Dalian University of TechnologyDalianChina

Curvilinear self-propelling of droplets has attracted great interest in the past few decades due to their irreplaceable roles in many *** understanding is that a droplet moves only along a preset channel formed by morphology or chemi-cal *** programmable curvilinear droplet motion independent of a preset channel remains greatly ***,we report a programmable curvi-linear self-propelling of droplets(circle,divergence,and convergence)based on the collaboration of the curvilinear wetting gradient and the Leidenfrost *** design achieves motion trajectory in a well-controlled manner as well as high velocity and long distance of droplet transport independent of the preset ***,the motion behaviors of droplets could be predicted accurately by theoretic *** envi-sion that our unique design could manifest extensive practical applications in fluidic devices,liquid transport,and heat transfer systems.

关键词： effect. curvilinear replace

Central Asia and Its Impact on China From a Geo-political Perspective

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China International Studies 2010年第3期30卷 37-53页

作者： feng yongping PhD at School of Political Science and Public Management Wuhan University

In the post-Cold War era,Central Asia's unique and important geo-political and economic values are being highlighted and are increasingly becoming the focus of contention among big powers and regional *** provides both opportunities and challenges. To turn challenges into opportunities and consolidate and make best use of the opportunities should become the priority goal of China's Central Asia policy.

关键词：地缘政治中亚中国冷战时期经济价值

UVR8-TCP4-LOX2 module regulates UV-B tolerance in Arabidopsis

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Journal of Integrative Plant Biology 2024年第5期66卷 897-908页

作者： Cheng Li Jiancan Du Huini Xu Zhenhua feng Caspar CCChater Yuanwen Duan yongping Yang Xudong Sun Yunnan Key Laboratory of Crop Wild Relatives Omics The Germplasm Bank of Wild SpeciesKunming Institute of BotanyChinese Academyof SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China CAs Key Laboratory of Tropical Plant Resources and Sustainable Use Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesKunming 650223China Faculty of Life Science and Technology Kunming University of Science and TechnologyKunming 650031China Royal Botanic Gardens KewRichmondSurrey TW93AEUK

The phytohormone jasmonate(JA)coordinates stress and growth responses to increase plant survival in unfavorable *** JA can enhance plant UV-B stress tolerance,the mechanisms underlying the interaction of UV-B and JA in this response remain *** this study,we demonstrate that the UV RESISTANCE LOCUS 8-TEOSINTE BRANCHED1,Cycloidea and PCF 4-LIPOXYGENASE2(UVR8-TCP4-LOX2)module regulates UV-B tolerance dependent on JA signaling pathway in Arabidopsis *** show that the nucleus-localized UVR8 physically interacts with TCP4 to increase the DNA-binding activity of TCP4 and upregulate the JA biosynthesis gene ***,UVR8 activates the expression of LOX2 in a TCP4-dependent *** genetic analysis also provides evidence that TCP4 acts downstream of UVR8 and upstream of LOX2 to mediate plant responses to UV-B *** results illustrate that the UV-B-dependent interaction of UVR8 and TCP4 serves as an important UVR8-TCP4-LOX2 module,which integrates UV-B radiation and JA signaling and represents a new UVR8 signaling mechanism in plants.

关键词： anthocyanin accumulation jasmonic acid TCP4 UV-B UVR8

A salt-induced tackifying polymer for enhancing oil recovery in high salinity reservoirs: Synthesis, evaluation, and mechanism

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GREEN ENERGY & ENVIRONMENT 2024年第11期9卷 1747-1758页

作者： Wu, Yining Li, Peihan Yan, Bin Li, Xiaohan Huang, yongping Yuan, Juncong feng, Xiang Dai, Caili China Univ Petr East China Dept Petr Engn Qingdao 266580 Peoples R China Sichuan Univ Coll Biomass Sci & Engn Dept Natl Engn Lab Clean Technol Leather Manufacture Chengdu 610065 Peoples R China Princeton Univ Dept Civil & Environm Engn Princeton NJ 08544 USA China Univ Petr East China Dept Chem Engn Qingdao 266580 Peoples R China

Polymer flooding is an effective method widely applied for enhancing oil recovery (EOR) by reducing the mobility ratio between the injected water and crude oil. However, traditional polymers encounter challenges in high salinity reservoirs due to their salt sensitivity. To overcome this challenge, we synthesized a zwitterion polymer (PAMNS) with salt-induced tackifying property through copolymerization of acrylamide and a zwitterion monomer, methylacrylamide propyl-N, N-dimethylbutylsulfonate (NS). NS monomer is obtained from the reaction between 1,4-butanesultone and dimethylamino propyl methylacrylamide. In this study, the rheological properties, salt responsiveness, and EOR efficiency of PAMNS were evaluated. Results demonstrate that PAMNS exhibits desirable salt-induced tackifying characteristics, with viscosity increasing up to 2.4 times as the NaCl concentration reaches a salinity of 30 x 10(4) mg L-1. Furthermore, high valence ions possess a much stronger effect on enhancing viscosity, manifested as Mg2+ > Ca2+ > Na+. Molecular dynamics simulations (MD) and fluid dynamics experiment results demonstrate that PAMNS molecules exhibit a more stretched state and enhanced intermolecular associations in high-salinity environments. It is because of the salt-induced tackifying, PAMNS demonstrates superior performance in polymer flooding experiments under salinity ranges from 5 x 10(4) mg L-1 to 20 x 10(4) mg L-1, leading to 10.38-19.83% higher EOR than traditional polymers. (c) 2023 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： High salinity reservoirs Salt-induced tackifying polymer Anti-polyelectrolyte behavior Enhanced oil recovery ZWITTERIONIC POLYMER BRUSHES SURFACE WATER BEHAVIOR

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大国崛起的安全困境与中日关系

现代国际关系 2005年第12期 35-40页

作者：封永平华东师范大学国际关系与地区发展研究院

表面上看,历史问题是当前中日关系紧张的焦点。但实际上,潜伏在历史问题背后的中日安全困境才是导致双边关系出现重大战略性变化的真正根源。中日间安全困境的形成有着深刻的大国崛起背景下的结构性原因,如不加缓解很可能成为两国走向... 详细信息

表面上看,历史问题是当前中日关系紧张的焦点。但实际上,潜伏在历史问题背后的中日安全困境才是导致双边关系出现重大战略性变化的真正根源。中日间安全困境的形成有着深刻的大国崛起背景下的结构性原因,如不加缓解很可能成为两国走向冲突的诱因。缓解或跳出这种局面的途径,在于培育和形成东亚区域安全共同体。这一途径对于中国的和平崛起有着根本意义。

关键词： “大国崛起” 国际安全中国日本外交关系

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地缘政治视野中的中亚及其对中国的影响

国际问题研究 2010年第2期 56-61页

作者：封永平武汉大学政治与公共管理学院

后冷战时期,中亚独特而重要的地缘政治经济价值开始凸显,日益成为各大国和地区力量博弈的焦点。这对中国既是机遇,也是挑战。化挑战为机遇,使机遇稳固化、最大化,应成为中国对中亚政策的优先目标。

关键词：中亚地缘价值中国战略选择