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

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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

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

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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

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

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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

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

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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

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

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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

Palladium Nanoparticles/Graphdiyne Oxide Nanocomposite with Excellent Peroxidase-like Activity and Its Application for Glutathione Detection

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Chemical Research in Chinese Universities 2022年第2期38卷 529-534页

作者： LAN Weifei HU ruifeng HUANG Danrong dong Xu SHEN Gangyi CHANG Shan DAI dongsheng School of Pharmacy Minzu University of ChinaBeijing 100081P.R.China Institute of Chemistry Chinese Academy of SciencesBeijing 100190P.R.China Institute of Bioinformatics and Medical Engineering School of Electrical and Information EngineeringJiangsu University of TechnologyChangzhou 213001P.R.China

In this study, palladium nanoparticles loaded graphdiyne oxide (Pd/GDYO) nanocomposite were fabricated by in-situ reduction of palladium chloride in the dispersion of GDYO, and characte-rized by Raman spectra, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The synthesized Pd/GDYO was first found to have catalytic activities similar to those of the peroxidase enzyme, which can catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine(TMB) in the presence of hydrogen peroxide(H2O2). Steady-state kinetic studies showed that the catalytic reaction of Pd/GDYO follows a ping-pong mechanism, and Pd/GDYO has a stronger activity to TMB with a Michaelis constant(Km) value of 5.32×10-4 mmol/L. Based on the shielding effect of glutathione(GSH) on the Pd/GDYO-H2O2-TMB reaction system, a colorimetric detection method for GSH was deve-loped with a wide linear range from 0.1 μmol/L to 40 μmol/L and a limit of detection of 0.1 μmol/L. The method was successfully applied for fast and accurate detection of GSH in injection powder drugs. It was expected that this peroxidase-like Pd/GDYO nano- composite would have wide applications in the fields of biomedicine and environmental chemistry.

关键词： Palladium nanoparticle/graphdiyne oxide nanocomposite Peroxidase-like activity Colorimetric detection Glutathione

Investigation on Fracture Properties of Single-Flawed Tunnel Model Under Medium-to-Low-Speed Impacts

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Acta Mechanica Solida Sinica 2020年第2期33卷 205-225页

作者： Lei Zhou Zheming Zhu ruifeng Liu Yong Fan Yuqing dong Peng Ying State Key Laboratory of Hydraulics and Mountain River Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Key Laboratory of Deep Underground Science and Engineering(Ministry of Education) College of Architecture and EnvironmentSichuan UniversityChengdu 610065China

Dynamic fractures occur frequently in geophysical processes and engineering applications.It is thus essential to study crack and failure behaviors,such as crack time-to-initiation,crack growth rate and arrest period under dynamic loading.In this study,impact experiments were implemented by utilizing the single-flawed tunnel specimens under drop-hammer impacts.Four brittle materials,i.e.,green sandstone,red sandstone,black sandstone and polymethyl methacrylate,were selected to make single-flawed tunnel specimens.Strain gauges and crack extension gauges were employed to measure the crack extension parameters.The properties of crack growth rate,crack time-to-initiation and arrest period of these four brittle materials were discussed and analyzed.The corresponding numerical simulation was performed by using the commercial software AUTODYN.The numerical results of crack growth rate and crack time-to-initiation agreed with the impact test results.The commercial software ABAQUS was applied to compute the dynamic stress intensity factors.The results show that both the dynamic initiation fracture toughness and the crack growth rate increase with the elastic moduli of these four types of brittle materials under the same loading conditions,whereas the crack time-to-initiation decreases with the increase in elastic moduli of the brittle materials under the same loading conditions.

关键词： Single-flawed tunnel Impact loading Crack growth rate Crack time-to-initiation Initiation fracture toughness

Disposition and fate of polyoxyethylene glycerol ricinoleate as determined by LC-Q-TOF MS coupled with MS^(ALL),SWATH and HR MS/MS techniques

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Chinese Chemical Letters 2021年第10期32卷 3237-3240页

作者： ruifeng Bai dong Sun Yuqin Shan Zhiqiong Guo Dafeng Chu John Paul Fawcett Jingkai Gu Center for Drug Metabolism Research School of Life SciencesJilin UniversityChangchun 130012China

Polyoxyethylene glycerol ricinoleate(PGR) serves as a solubilizer/emulsifier that is commonly used in pharmaceutical formulations despite being associated with severe anaphylactoid hypersensitivity reactions.Cremophor EL?(CrEL) is the most representative PGR produced from reacting ethylene oxide with castor oil.To help clarify the cause of side effects and potentially improve the safety of PGR-based drug delivery vehicle,we have developed separate but related analytical methods for the quantitation of CrEL and its main metabolites,glycerol ethoxylate(GE) and ricinoleic acid(RA).Since CrEL and GE are highly disperse mixtures of polymers that are not amenable to analysis by conventional liquid chromatographytandem mass spectrometry(LC-MS/MS),we used liquid chromatography-triple-quadrupole-time-of-flight mass spectrometry(LC-Q-TOF MS) combined with product ion data acquisition by MSALLand sequential window acquisition of all theoretical fragments mass spectrometry(SWATH MS),respectively to perform the analysis.In contrast,RA is a single molecular entity that could be readily analyzed using conventional LC-HR MS/MS.Selection of specific fragment ions for CrEL,GE,RA and their internal standards enabled a precise quantitation of such a complex analytes system in rat plasma after a single and simple sample preparation method.Assay validation indicated linearity for CrEL,GE and RA over the concentration ranges 0.2~20.0 μg/mL,0.1~10.0 μg/mL and 0.1~20.0 μg/m L,respectively with satisfactory results for other validation parameters.A subsequent pharmacokinetic study involving single intravenous 200 mg/kg injections of CrEL to rats showed the methods enable comprehensive and high throughput quantitation of CrEL and its metabolites in a biological matrix.Our combination of assays provides effective application in investigating the cause of the hypersensitivity reaction of PGR and potentially to improve its safety for using as a vehicle in drug formulations.

关键词： Polyoxyethylene glycerol ricinoleate Cremophor EL LC-Q-TOF MS Glycerol ethoxylate Ricinoleic acid

Heroes of the Fight Against Covid-19

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求是:英文版 2021年第1期13卷 54-62页

作者： Chen Fang Qu Ting Chen Cong dong ruifeng 不详

Hero is a weighty word,but one that has truly become familiar to every Chinese person in the great battle against Covid-19.Zhong Nanshan,Zhang Boli,Zhang Dingyu,and Chen Wei are the outstanding representatives of China’s heroes.Standing up at a time of crisis,they risked their lives to fight the epidemic,manifesting the determination of the 1.4 billion Chinese people to come together and bravely push forward.

关键词： push truly fight