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Effect of grain boundary Widmanstättenαcolony on the anisotropic tensile properties of directed energy deposited Ti-6Al-4V alloy

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Journal of Materials Science & Technology 2024年第17期184卷 145-156页

作者： Wei Fan Yijie Peng Yongxia Wang Yang Qi zhe feng Hua Tan fengying Zhang Xin Lin State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Material Science and Engineering Chang’an UniversityXi’an 710064China

Columnar grain structure caused anisotropy in mechanical properties,especially in elongation,is an important concern for Ti-6Al-4 V alloy fabricated by directed energy deposition(DED).Several strategies have been proposed to reduce anisotropy by globularizing the grains,but these conventional approaches are costly and inefficient due to challenges faced during producing the columnarβ-grain ***,understanding the impact of columnar grain-related microstructures on the anisotropic deformation behavior is still *** the recognition of the importance of grain boundary Widmannstättenαcolony(αWGB)as a grain-related microstructure,it has received limited attention in available literature on anisotropy in mechanical *** study employed in-situ induction heating during DED to controlαWGB formation,yielding three Ti-6Al-4 V samples with varyingαWGB *** deforma-tion ofαWGB and its impact on elongation in build and transverse directions were analyzed.αWGB width grew from 0.5μm to 32.4μm via diffusion-controlled growth due to reduced cooling *** deformation led to dislocation movement and accumulation,causing early failure and worsened ductile anisotropy withinα***,largerαWGB size significantly exacerbated anisotropy in *** work underscoresαWGB’s role in anisotropic deformation and offers insights for optimizing mechanical properties in DED-fabricated titanium alloys.

关键词： Additive manufacturing Directed energy deposition Anisotropic mechanical properties Titanium alloy Microstructure

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Determination of Sparfloxacin in Human Urine by Reversed-Phase High Performance Liquid Chromatography With Nitrous Acid and Hydroiodic Pre-Column Derivatization

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Chinese Chemical Letters 2001年第11期12卷 1007-1010页

作者： Li Ming DU zhe feng FAN Jin Li QIAO Jing Ping WANG Analysis and Test Center Shanxi Teachers UniversityLingfen 041004 Department of Chemistry Arts and Sciences CollegeTaiyuan University of TechnologyTaiyuan 030006

Sparfloxacin can be oxidized by nitrous acid, then react with hydroiodic acid to form a fluorescent derivative. Based on this, a reversed-phase high performance liquid chromatographic pre-column derivatization new method is described for the determination of sparfloxacin in human urine. The linear range is 0.05 mg/L to 4.0 mg/L, the recoveries are 91.5%similar to 95.7% and the RSD is 1.2%similar to4.2%. The results showed that this method is suitable for the determination of sparfloxacin in human urine.

关键词： sparfloxacin HPLC pre-column derivatization human urine

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Overcoming the limitation of in-situ microstructural control in laser additive manufactured Ti-6Al-4V alloy to enhanced mechanical performance by integration of synchronous induction heating

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Journal of Materials Science & Technology 2021年第35期94卷 32-46页

作者： Wei Fan Hua Tan fengying Zhang zhe feng Yongxia Wang Lai-Chang Zhang Xin Lin Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi'an 710072China School of Material Science and Engineering Chang'an UniversityXi'an 710064China School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia

Although a variety of processing routes were developed to in-situ manipulate microstructure for fabricating high-performance Ti-6Al-4 V alloy by directed energy deposition(DED),the in-situ microstructural control ability has been limited and lead to a narrowed mechanical property control *** work proved the microstructural correlation betweenβ-grains andα-laths resulting from the unique thermal characteristics of DED for the first time and solved such a dilemma through synchronous induction heating assisted laser deposition(SILD)*** results confirmed that the laser energy and inductive energy have a different effect on the solidification and solid phase transformation *** adjusting the laser-induction parameters,the microstructural correlation can be tuned;theβ-grains andα-laths can be controlled relatively separately,thereby significantly enhancing the ductility of as-deposited sample(elongation from 14.2%to 20.1%).Furthermore,the mechanical properties of the tuned microstructures are even comparable to that of DED Ti-6Al-4 V with post heat treatment,which indicates that the potential of SILD to be a one-step manufacturing process to fabricate high performance components without post heat ***,the tensile testing results of the tuned microstructures indicate thatα-lath size is more influential on the mechanical properties than theβ-grain size due to its stronger hindering effect on the slipping of *** work promotes the understanding of the microstructural formation mechanism in DED titanium alloy and proves that the combination of synchronous induction and laser can expand the ability to control the microstructure and properties of multi-layer deposition.

关键词： Directed energy deposition Additive manufacturing Ti-6Al-4V In-situ microstructural control Mechanical properties

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Nef Mutations in Long-term Non-progressors from Former Plasma Donors Infected with HIV-1 Subtype B in China

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Biomedical and Environmental Sciences 2008年第6期21卷 485-491页

作者： SHU-HUA WANG HUI XING XIANG HE feng-XIA ZHU zhe-feng MENG Yu-HUA RUAN YI-MING SHAO State Key Laboratory for Infection Diseases Prevention and Control National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and Prevention Beijing 100050 China The General Hospital of Civil Aviation Administration of China Beijing 100025 China

Objective To study the specific amino acid variation in Nef that may be related to disease progression after infection with HIV-1 subtype B, a predominant strain circulating in China, and to determine whether changes in Nef secondary structure may influence different stages of AIDS development based on the concept that the Nef gene of HIV infection dramatically alter the severity of viral infection and virus replication and disease progression, and that long-term non-progressors （LTNP） of HIV infection are commonly associated with either a deletion of the Nef gene or the defective Nef alleles. Methods The study subjects were divided into LTNPI（n=14）, LTNP2 （n=16） and slow progressor （SP, n=19） groups for mutational analysis of the Nef sequence. The data were obtained by using Bioedit, MEGA, Anthewin and SAS software. Results Residues in Nef TA48/49 and K151 occurred more frequently in the LTNP group while AA48/49 was more frequently observed in the SP group. Of the differences observed in the secondary structure comparison using Nef consensus sequences of these three groups, one was roughly corresponding to the Nef48/49 mutation site. Conclusion TA48/49, Kiss, and AA48/49 in the Nef gene might be associated with the different stages of HIV infection, and there may be a link between the Nef secondary structure and the progression of HIV- 1 infection.

关键词： HIV-1 Nef Long-term nonprogressors Sequence mutations Secondary structure prediction

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Recognition of mortar pumpability via computer vision and deep learning

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Journal of Electronic Science and Technology 2023年第3期21卷 73-81页

作者： Hao-zhe feng Hong-Yang Yu Wen-Yong Wang Wen-Xuan Wang Ming-Qian Du Research Institute Electronic Science and Technology University of Electronic Science and Technology of ChinaChengdu611731China School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China The Second Research Institute of Civil Aviation Administration of China Chengdu610041China

The mortar pumpability is essential in the construction industry,which requires much labor to estimate manually and always causes material *** paper proposes an effective method by combining a 3-dimensional convolutional neural network(3D CNN)with a 2-dimensional convolutional long short-term memory network(ConvLSTM2D)to automatically classify the mortar *** results show that the proposed model has an accuracy rate of 100%with a fast convergence speed,based on the dataset organized by collecting the corresponding mortar image *** work demonstrates the feasibility of using computer vision and deep learning for mortar pumpability classification.

关键词： Classification Computer vision Deep learning Pumpability 2-dimensional convolutional long short-term memory network (ConvLSTM2D) 3-dimensional convolutional neural network(3D CNN)

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Emergence of Multidrug-Resistant Proteus mirabilis Harboring both blaNDM-1 and cfr genes

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Biomedical and Environmental Sciences 2024年第10期37卷 1208-1212页

作者： Meiqing Sun Xiuhong Yang Beibei Miao Jingyi Zhang Shuang Meng zhe feng Juan Li National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China Wuqing District Centre for Disease Control and Prevention Tianjin 301700China Baoshan Disease Control and Prevention Baoshan 678000YunnanChina

Proteus mirabilis is abundant in soil and water,and although it is part of the normal human intestinal flora(along with Klebsiella species and Escherichia coli),it is known to cause serious infections in humans,with a fatality rate of 20%-50%[1].Proteus mirabilis is intrinsically resistant to tetracycline,tigecycline,and *** widespread and irregular use of antimicrobial agents,*** antimicrobial resistance has *** acquire antimicrobial resistance(AMR)by capturing plasmids,transposons,or other mobile elements harboring antimicrobial resistance *** mechanism allows the rapid selection and transmission of numerous AMR genes in clinical,veterinary,food production,transportation,and environmental settings.

关键词： lis Proteus ant

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Hydrogen-bonded Intramolecular Charge Transfer Excited State of Dimethylaminobenzophenone using Time Dependent Density Functional Theory

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Chinese Journal of Chemical Physics 2012年第6期25卷 654-658,I0003页

作者： Yu-ling Chu Zhong Yang zhe-feng Pan Jing Liu Yue-yi Han Yong Ding Peng Song Physical and Electronic and Information Engineering Institute Chifeng University Chifeng 024001China Department of Physics Liaoning University Shenyang 110036 China Department of Science Shenyang Aerospace University Shenyang 110136 China

Density functional theory and time-dependent density-functional theory have been used to investigate the photophysical properties and relaxation dynamics of dimethylaminobenzophe- none （DMABP） and its hydrogen-bonded DMABP-MeOH dimer. It is found that, in non- polar aprotic solvent, the transitions from So to S1 and S2 states of DMABP have both n→π and π→π＊ characters, with the locally excited feature mainly located on the C=O group and the partial CT one characterized by electron transfer mainly from the dimethylaminophenyl group to the C=O group. But when the intermolecular hydrogen bond C=O…H-O is formed, the highly polar intramolecular charge transfer character switches over to the first excited state of DMABP-MeOH dimer and the energy difference between the two low- lying electronically excited states increases. To gain insight into the relaxation dynamics of DMABP and DMABP-MeOH dimer in the excited state, the potential energy curves for con- formational relaxation are calculated. The formation of twisted intramolecular charge trans- fer state via diffusive twisting motion of the dimethylamino/dimethylaminophenyl groups is found to be the major relaxation process. In addition, the decay of the Si state of DMABP-MeOH dimer to the ground state, through nonradiative intermolecular hydrogen bond stretching vibrations, is facilitated by the formation of the hydrogen bond between DMABP and alcohols.

关键词： Hydrogen-bond Intramolecular charge transfer Relaxation dynamic Twistingdynamic

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Laser powder bed fusion of high-strength Sc/Zr-modified Al–Mg alloy:phase selection,microstructural/mechanical heterogeneity,and tensile deformation behavior

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Journal of Materials Science & Technology 2021年第36期95卷 40-56页

作者： Zihong Wang Xin Lin Nan Kang Jing Chen Hua Tan zhe feng Zehao Qin Haiou Yang Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi'an 710072China

Laser powder bed fusion(L-PBF)of Sc/Zr-modified Al-based alloys has recently become a promising method for developing a new generation of high-performance Al *** clarify the modification roles of Sc/Zr elements,an Al–4.66Mg–0.48Mn–0.72Sc–0.33Zr(wt.%)alloy was processed using *** effect of the local solidification condition of the molten pool on the precipitation behavior of primary Al_(3)(Sc,Zr)was analyzed based on time-dependent nucleation *** was found that primary Al_(3)(Sc,Zr)inevitably precipitated at the fusion boundary,while its precipitation could be effectively suppressed in the inner region of the molten *** subsequently induced the formation of a heterogeneousα-Al *** direct aging,the heredity of solidification microstructure introduced heterogeneous secondary Al_(3)(Sc,Zr)precipitates withinα-Al *** to the inverse relationship between grain boundary strengthening and precipitation strengthening,the direct-aged sample with dual heterogeneous structures exhibited reduced mechanical heterogeneity,resulting in lowered hetero-deformation-induced *** low strain-hardening capability in the direct-aged sample promoted necking instability while inducing a large Lüders elongation,which effectively improved the tensile ductility.

关键词： Additive manufacturing Al–Mg–Sc–Zr alloys Laser powder bed fusion Heterogeneous microstructure Deformation behavior

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GsMAPK4,a positive regulator of soybean tolerance to salinity stress

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Journal of Integrative Agriculture 2019年第2期18卷 372-380页

作者： QIU You-wen feng zhe FU Ming-ming YUAN Xiao-han LUO Chao-chao YU Yan-bo feng Yan-zhong WEI Qi LI feng-lan College of Life Science Northeast Agricultural UniversityHarbin 150030P.R.China Heilongjiang Institute of Education Harbin 150030P.R.China Heilongjiang Academy of Agricultural Sciences Harbin 150086P.R.China

Salt stress is one of the major factors affecting plant growth and yield in soybean under saline soil condition. Despite many studies on salinity tolerance of soybean during the past few decades, the detailed signaling pathways and the signaling molecules for salinity tolerance regulation have not been clarified. In this study, a proteomic technology based on two-dimensional gel electrophoresis(2-DE) and mass spectrometry(MS) were used to identify proteins responsible for salinity tolerance in soybean plant. Real-time quantitative PCR(qRT-PCR) and Western blotting(WB) were used to verify the results of 2-DE/MS. Based on the results of 2-DE and MS, we selected glucosyltransferase(GsGT4), 4-coumarate, coenzyme A ligase(Gs4 CL1), mitogen-activated protein kinase 4(GsMAPK4), dehydration responsive element binding protein(GsDREB1), and soybean cold-regulated gene(GsSRC1) in the salinity tolerant soybean variety, and GsMAPK4 for subsequent research. We transformed soybean plants with mitogen-activated-protein kinase 4(GsMAPK4) and screened the resulting transgenics soybean plants using PCR and WB, which confirmed the expression of GsMAPK4 in transgenic soybean. GsMAPK4-overexpressed transgenic plants showed significantly increased tolerance to salt stress, suggesting that GsMAPK4 played a pivotal role in salinity tolerance. Our research will provide new insights for better understanding the salinity tolerance regulation at molecular level.

关键词： soybean salinity tolerance two-dimensional gel electrophoresis GsMAPK4

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Effective Stacking Fault Energy in Face-Centered Cubic Metals

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Acta Metallurgica Sinica(English Letters) 2018年第8期31卷 873-877页

作者： Ke-Qiang Li zhen-Jun Zhang Lin-Lin Li Peng Zhang Jin-Bo Yang zhe-feng Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

As a typical configuration in plastic deformations, dislocation arrays possess a large variation of the separation of the partial dislocation pairs in face-centered cubic（fcc） metals. This can be manifested conveniently by an effective stacking fault energy（SFE）. The effective SFE of dislocation arrays is described within the elastic theory of dislocations and verified by atomistic simulations. The atomistic modeling results reveal that the general formulae of the effective SFE can give a reasonably satisfactory prediction for all dislocation types, especially for edge dislocation arrays. Furthermore, the predicted variation of the effective SFE is consistent with several previous experiments, in which the measured SFE is not definite, changing with dislocation density. Our approach could provide better understandings of cross-slip and the competition between slip and twinning during plastic deformations in fcc metals.

关键词： Face-centered cubic Stacking fault energy - Dislocation dissociation Atomistic modeling

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