检索结果-南通市图书馆

Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang Chuang Yu Wensheng Yang ruifeng dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech Co. Ltd.Langfang065201China National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials Co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a combined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was investigated.By reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt solidifies.The enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum content of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this combined method.Additionally,this paper provides a new method for the removal of high density and low evaporation coefficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

Correlation between the mechanical properties and the<110>texture in a hot-rolled nearβtitanium alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第2期97卷 165-168页

作者： ruifeng dong Xiaoyang Zhang Chenhui Li Yuhong Zhao Jinzhong Tian Li Wu Hua Hou School of Materials Science and Engineering North University of ChinaTaiyuanShanxi 030051PR China State Key Laboratory of Solidification ProcessingNorthwestern Polytechnical UniversityXi’anShaanxi 710072PR China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’anShaanxi 710072PR China

1.Introduction Nearβtitanium alloys have been considered as a potential material to fabricate high-strength fasteners in aerospace field owing to their high specific strength,good crack and fatigue resistance[1,2].It is well known that the processing technology determines the microstructure,and the microstructure eventually correlates with the performance of alloys.

关键词： microstructure strength alloy

Recovery of waste heat in cement plants for the capture of CO2

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2012年第1期6卷 104-111页

作者： ruifeng dong Zaoxiao ZHANG Hongfang LU Yunsong YU State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Large amounts of energy are consumed during the manufacturing of cement especially during the calcination process which also emits large amounts of CO2. A large part of the energy used in the making of cement is released as waste heat. A process to capture CO2 by integrating the recovery and utilization of waste heat has been designed. Aspen Plus software was used to calculate the amount of waste heat and the efficiency of energy utilization. The data used in this study was based on a dry process cement plant with a 5-stage preheater and a precalciner with a cement output of 1 Mt/y. According to the calculations： 1） the generating capacity of the waste heat recovery system is 4.9MW. 2） The overall CO2 removal rate was as high as 78.5%. 3） The efficiency of energy utilization increased after the cement producing process was retrofitted with this integrated design.

关键词： cement industry waste heat recovery utiliza-tion CO2 removal

Dependence of mechanical properties on the microstructure characteristics of a near β titanium alloy Ti-7333

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第1期35卷 48-54页

作者： ruifeng dong Jinshan Li Hongchao Kou Jiangkun Fan Bin Tang State Key Laboratory of Solidification Processing Northwestern Polytechnical University National & Local Joint Engineering Research Center for Precision Thermoforming Technology of Advanced Metal Matfigerials

In this work, the microstructure and the corresponding tensile properties of the rolled Ti-7Mo-3Nb-3Cr-3Al(Ti-7333) alloy before and after the thermal treatments were investigated. The results show that a strong α-fiber texture is developed in the rolled Ti-7333 alloy. The deformed matrix and the texture significantly induce the variant selection of β phase. The high strength of the rolled Ti-7333 alloy is attributed to the texture parallel to the tensile direction and the dispersed α phase within the matrix. After the solution treatment followed by the aging treatment, the texture decreases and the microstructure consists of the equiaxed β grains, the spheroidal α_p phase and various needle-like α variants. Eventually, the alloy could achieve an optimal combination with the strength of about 1450 MPa,the ductility of about 10.5% and a considerable shear strength of about 775 MPa. This balance can be ascribed to the performance of the spheroidal α_p phase and various needle-like α_s variants. The results indicate that the Ti-7333 alloy could be a promising candidate material for the high-strength fastener.

关键词： Near β titanium alloy Hot-rolled Ti-7333 Texture Thermal treatment α phase Mechanical properties

Morphology characteristics of α precipitates related to the crystal defects and the strain accommodation of variant selection in a metastableβtitanium alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第36期95卷 1-9页

作者： ruifeng dong Hongchao Kou Yuhong Zhao Xiaoyang Zhang Ling Yang Hua Hou School of Materials Science and Engineering North University of ChinaTaiyuan030051China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China

Profound and comprehensive investigations on the morphology characteristics ofαprecipitates are essential for the microstructural control of metastableβtitanium alloys.At the very beginning of aging treatment,intragranularαprecipitates with a dot-like morphology begin to generate nearby the dislocations,then those dot-likeαprecipitates with the same crystallographic orientation tend to connect with each other to develop a lath-like morphology.With the progress of aging treatment,the orientated lath-likeαprecipitates gradually combine with each other to form the V-shaped clusters or the triangular ones.The dislocations of{110}_(β)βedge type are evidenced within theβgrains,and it is found that variant selection ofαprecipitates induced by the transformation strain and the interplay betweenαvariants and the dislocations are confirmed as the key factors for the formation of the V-shaped or triangular clusters.The results of this work could provide underlying knowledge on the morphology characteristics of intraguranularαprecipitates related to the crystal defects and the strain accommodation ofαvariants in metastableβtitanium alloys.

关键词： Metastableβtitanium alloys αPrecipitates Morphology characteristics Phase transformation Strain accommodation Dislocations

Hot-corrosion behavior associated with the evolution of corrosion scales of a Ni-based superalloy in molten salts

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2021年第3期31卷 486-492页

作者： ruifeng dong dong Liu Tiebang Zhang Ling Yang Li Wu Yuhong Zhao Hua Hou School of Materials Science and Engineering North University of China State Key Laboratory of Solidification Processing Northwestern Polytechnical University School of Science of NUC North University of China

The degradation of Ni-based superalloys in molten salts is closely related with the evolution of corrosion scales. In this work, the evolution of corrosion scales, the characteristics of the scale/alloy matrix interface associated with the corrosion mechanisms and the corrosion kinetics of a Ni-based superalloy Ni–20 Cr–18 W in molten salts were investigated. The outer surface of the corrosion scales was composed of numerous flakes. From the cross-sectional view, the scales gradually presented a layered structure and its formation can be ascribed to the morphology evolution of the inclusions inserted within the scales. It was found that the corrosion progress was a cooperative process involving in both oxidation and sulfuration, and the element of sulfur(S) took the precedence to penetrate into the matrix and resulted in an obvious sulfuration zone nearby the scales/alloy matrix interface. The corrosion activation energy of the investigated alloy was calculated to be 125.27 k J/mol. This work is expected to work out the structural evolution of the corrosion scales and the characteristics of the scale/matrix interface associated with the corrosion mechanisms for Ni-based superalloys.

关键词： Ni-based superalloys Hot corrosion Molten salts Corrosion scales Scales/matrix interface Corrosion mechanism

ω-Assisted refinement of α phase and its effect on the tensile properties of a near β titanium alloy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第9期44卷 24-30页

作者： ruifeng dong Jinshan Li Hongchao Kou Jiangkun Fan Yuhong Zhao Hua Hou Li Wu College of Materials Science and Engineering North University of ChinaTaiyuan 030051China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

In this work, the phase transformation sequence during the continuous heating process(3℃/min) was investigated in a near β titanium alloy. The results show that the staring formation of ω phase is about267℃, and the ending precipitation temperature about 386℃ during the heating process. When the heating temperature is greater than 485℃, there are no ω phase detected within the β matrix. Combined with the microstructural characterization, it is found that ω phase facilitates the nucleation of αphase nearby the ω/β interface and has a great effect on the refinement for α phase. As compared with the specimens directly aged, the specimens with ω-assisted refinement of α phase possess high tensile strength, but there is no yield stage detected on their stress-strain curve. Combined with the analyses of the fracture morphology, the specimens with ω-assisted refinement of α phase present a brittle fracture.This is mainly ascribed to its relatively lager width of grain boundaries and the absence of widmanst?ttenα precipitates.

关键词： Neartitanium alloy Continuous heating Phase transformation -Assisted nucleation Precipitation Tensile properties

新型电力系统背景下铅酸蓄电池监测系统的发展情况探究

在线全文

学校读者我要写书评

暂无评论

通信电源技术 2024年第1期41卷 77-81页

作者：王放放赵光金董锐锋胡玉霞国网河南省电力公司电力科学研究院河南郑州450000

在“双碳”背景下,因新能源发电日益增加,传统电力系统结构发生改变,逐渐向着新型电力系统转型。然而新能源本身的波动性会影响新型电力系统的稳定运行,因此需要提高系统的灵活运行能力。在新型电力系统中,铅酸蓄电池作为储备能源而广... 详细信息

在“双碳”背景下,因新能源发电日益增加,传统电力系统结构发生改变,逐渐向着新型电力系统转型。然而新能源本身的波动性会影响新型电力系统的稳定运行,因此需要提高系统的灵活运行能力。在新型电力系统中,铅酸蓄电池作为储备能源而广泛使用,是整个系统安全稳定运行的重要保障。铅酸蓄电池在使用过程中可能会面临热失控、极板硫酸盐化、腐蚀以及失水等问题,通过在线监测铅酸蓄电池的电压、温度、内阻及电流等性能参数,可以准确反映电池内部情况,确保电池的安全使用,为新型电力系统的稳定运行奠定基础。文章主要分析铅酸蓄电池的工作原理,并总结其失效的影响因素,结合铅酸蓄电池的性能参数分析铅酸蓄电池监测系统的现状与发展趋势。

关键词：新型电力系统铅酸蓄电池在线监测系统

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

燃煤锅炉SCR脱硝系统的喷氨优化策略验证

工业炉 2024年第1期46卷 15-20页

作者：王冰杨硕张小霓董锐锋陈浩军许旭斌润电能源科学技术有限公司国网河南省电力公司电力科学研究院

提出了一种SCR脱硝系统的喷氨优化方法，基于SCR入口的NOx质量分布对喷氨格栅进行初调，再根据SCR出口的NOx质量浓度分布进行二次调整。依此优化调整策略，对某600 MW燃煤机组开展试验，结果表明：100%负荷工况下SCR出口两侧NOx质量浓... 详细信息

提出了一种SCR脱硝系统的喷氨优化方法，基于SCR入口的NOx质量分布对喷氨格栅进行初调，再根据SCR出口的NOx质量浓度分布进行二次调整。依此优化调整策略，对某600 MW燃煤机组开展试验，结果表明：100%负荷工况下SCR出口两侧NOx质量浓度分布均匀性明显提高，相对标准偏差由56.4%、69.1%降至12.0%、11.6%；供氨流量降低28.8%、26.9%;SCR出口氨逃逸平均体积比由3.0μL/L降至1.3μL/L，氨逃逸峰值由4.5μL/L降至1.6μL/L，消除局部喷氨过量现象，试验效果显著。

关键词： SCR脱硝喷氨优化调整 NOx质量浓度分布氨逃逸体积比

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

稀土元素对耐蚀钢腐蚀性能影响的研究综述

山东冶金 2024年第1期46卷 28-33,38页

作者：雷元素董瑞峰母志鹏周培英吴彦杰内蒙古工业大学材料科学与工程学院内蒙古呼和浩特010051

随着工业的不断发展,世界各国对钢材质量的要求也越来越高,如何提高钢材的耐蚀性,已成为目前的研究重点。耐蚀钢因其具有较强的抗腐蚀性能,广泛应用于土木建筑、汽车制造、造船等领域,为进一步提高耐蚀钢的耐腐蚀性能,通常在钢中添加稀... 详细信息

随着工业的不断发展,世界各国对钢材质量的要求也越来越高,如何提高钢材的耐蚀性,已成为目前的研究重点。耐蚀钢因其具有较强的抗腐蚀性能,广泛应用于土木建筑、汽车制造、造船等领域,为进一步提高耐蚀钢的耐腐蚀性能,通常在钢中添加稀土元素。文中综述了稀土元素对耐蚀钢的净化作用、对钢内夹杂物的影响、对钢材腐蚀性能及锈层影响的研究进展,为促进稀土元素在钢中的应用提供理论依据。稀土元素对耐蚀钢耐蚀性影响的具体机理和稀土元素在材料工程中的可持续发展是当前研究的重点。

关键词：耐蚀钢稀土元素夹杂物耐蚀性锈层