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Shipeng Wang,Xiaohui Cui,Ang Xiao,Peng Zhao,Lei Zhang 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2
In this study, the effect of induced electro-pulsing treatment (IEPT) on the microstructure evolution and correspondingchanges in the mechanical properties of pre-stretched 5052-O aluminum alloy was investigated. Microstructural changesin the alloy were observed using electron backscatter diffraction, transmission electron microscopy, and scanning electronmicroscopy. The application of induced current significantly reduced the yield strength of pre-stretched specimens whilethe elongation increased. In terms of microstructure, more uniformly distributed dimples were observed after induced currentapplication, which indicate the increased plasticity of the alloy. The average grain size and number of low angle grainboundaries increased with application of induced current. The texture types did not change, however, the cube-type texturebecame less pronounced, whereas brass-type and copper-type textures were enhanced. Furthermore, the dislocation densitydecreased and dislocation rearrangement occurred. Thus, IEPT provides a new way to alter the microstructure and mechanicalproperties of the deformed components.
Shipeng Wang,Xiaohui Cui,Ang Xiao,Lei Zhang,Peng Zhao 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3
In this study, the effect of induced electro-pulsing treatment (IEPT) on the microstructure evolution and correspondingchanges in the mechanical properties of pre-stretched 5052-O aluminum alloy was investigated. Microstructural changesin the alloy were observed using electron backscatter diffraction, transmission electron microscopy, and scanning electronmicroscopy. The application of induced current significantly reduced the yield strength of pre-stretched specimens whilethe elongation increased. In terms of microstructure, more uniformly distributed dimples were observed after induced currentapplication, which indicate the increased plasticity of the alloy. The average grain size and number of low angle grainboundaries increased with application of induced current. The texture types did not change, however, the cube-type texturebecame less pronounced, whereas brass-type and copper-type textures were enhanced. Furthermore, the dislocation densitydecreased and dislocation rearrangement occurred. Thus, IEPT provides a new way to alter the microstructure and mechanicalproperties of the deformed components.
Wang Ying,Wang Guangke,Hu Tao,Wen Shipeng,Hu Shui,Liu Li 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7
Photons with the energy of 60 keV are regularly used for some kinds of bone density examination devices, like the single photon absorptiometry (SPA). This article reports a flexible and lightweight rare earth/polymer composite for enhancing shielding efficiency against photon radiation with the energy of 60 keV. Lead oxide (PbO) and several rare earth element oxides (La2O3, Ce2O3, Nd2O3) were dispersed into natural rubber (NR) and the photon radiation shielding performance of the composites were assessed using monte carlo simulation method. For 60 keV photons, the shielding efficiency of rare earthbased composites were found to be much higher than that of the traditional lead-based composite, which has bad absorbing ability for photons with energies between 40 keV and 88 keV. In comparison with the lead oxide based composite, Nd2O3-NR composite with the same protection standard (the lead equivalent is 0.25 mmPb, 0.35 mmPb and 0.5 mmPb, respectively), can reduce the thickness by 35.29%, 37.5% and 38.24%, and reduce the weight by 38.91%, 40.99% and 41.69%, respectively. Thus, a flexible, lightweight and lead-free rare earth/NR composite could be designed, offering efficient photon radiation protection for the users of the single photon absorptiometry (SPA) with certain energy of 60 keV
Shipeng Yang,Qiwen Zhong,Jie Tian,Lihui Wang,Mengliang Zhao,Li Li,Xuemei Sun 한국유전학회 2018 Genes & Genomics Vol.40 No.10
In recent years, Jerusalem artichoke has received widespread attention as a novel source of sugar, biofuel, and animal feed. Currently, only few gDNA-SSRs derived from sunflower were verified in the Jerusalem artichoke; therefore, it is particularly important to develop SSR primer markers that belonged to Jerusalem artichoke resources. Using EST data to develop EST-SSR markers is simple and effective. In order to understand the general characteristics of SSR markers in Jerusalem artichoke EST sequences and accelerate the use of SSR markers in Jerusalem artichoke research. This study used 40,370 sequenced unigene fragments and MISA software to identify SSR loci. The 48 pairs of EST-SSR primers assessed for the identification of 45 varieties of Jerusalem artichoke. Cluster, genetic diversity parameters and AMOVA analysis was conducted using the genetic similarity coefficient, revealing genetic differences between 48 genetic material. A total of 1204 SSR loci were identified with 13 different types of repeats, distributed among 1020 EST sequences, of which trinucleotide repeats were the most common, accounting for 38.21% of the total SSR loci. Among the 44 repeat motifs, AG/CT, AAG/ CTT, and ATC/ATG motifs had the highest frequencies, accounting for 22.45, 14.71, and 7.84% of all motifs, respectively. From these sequences, 48 pairs of EST-SSR primers were designed, and 22 primer pairs for loci with high polymorphism were selected to analyze the genetic diversity of 45 Jerusalem artichoke germplasm sources. The results indicated that the variation range of the effective number of alleles for 22 primers ranged between 1.7502 and 4.5660. The Shannon’s information index ranged between 0.6200 and 1.6423. The variation range of PIC ranged between 0.3121 and 0.6662 with an average of 0.5184. Cluster analysis was conducted using the genetic similarity coefficient, revealing significant genetic differences between Asian and European genetic material. Cluster analysis revealed a relationship between the genotypes and geographic origins of the Jerusalem artichoke. The results of AMOVA as well as the genetic identity and genetic distance in the Jerusalem artichoke population showed that there presented certain genetic heterogeneity in Jerusalem artichoke genetic structure of 45 samples from seven different geographic populations. The Jerusalem artichoke EST-SSR marker system established in this study provides an effective molecular marker system for future research focused on Jerusalem artichoke genetic diversity and the breeding of new varieties.
Xiaohui Shan,Xiaoyu Wang,Guang Yang,Ying-Wu Lan,Shengzhong Su,Shipeng Li,Hongkui Liu,Yaping Yuan 한국식물학회 2013 Journal of Plant Biology Vol.56 No.1
DNA methylation plays a vital role in tuning geneexpression in response to environmental stimuli. Here,methylation-sensitive amplified polymorphisms (MSAP)were used to assess the effect of cold stress on the extent andpatterns of DNA methylation in maize seedlings. Overall,cold-induced genome-wide DNA methylation polymorphismsaccounted for 32.6 to 34.8% of the total bands at the differenttreatment time-points. It was demonstrated that the extentand pattern of DNA methylation was induced by cold stressthrough the cold treatment process and that thedemethylation of fully methylated fragments was the maincontributor of the DNA methylation alterations. The sequencesof 28 differentially amplified fragments relevant to stresswere successfully obtained. Under the cold stress, demethylationwas detected in most fragments. BLAST results indicate thatthe homologues of these fragments are involved in manyprocesses, including hormone regulation, cold response,photosynthesis, and transposon activation. The expressionanalysis demonstrated an increase in the transcription of fivedemethylated genes. Despite the fact that DNA methylationchanges and cold acclimation are not directly associated, ourresults may indicate that the specific demethylation of genesis an active and rapid epigenetic response to cold in maizeduring the seedling stage, further elucidating the mechanismof maize adaptation to cold stress.
A Teleoperated Robotic Catheter System with Motion and Force Feedback for Vascular Surgery
Olatunji Mumini OMISORE,ShiPeng HAN,LingXue REN,Lei WANG 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
In recent time, robotic catheter systems have been proposed to minimize major limitations in minimally invasive vascular surgery. Technical evaluations of conventional systems have shown that teleoperation of robot-based systems could provide feasible and safe treatment method for vascular abnormalities. However, despite the merits, robot-assisted vascular surgeries are performed in fewer clinical centres, worldwide. In this study, a 2-DoF teleoperated robotic catheter system is proposed for treatment of vascular catheterization. The system provides visual feedbacks of motion and force information during catheterization procedures. Operation of the robotic catheter system was experimentally validated using master-slave teleoperation system. In the experiments, different phantom models of human vasculature were catheterized and the results obtained shows that the proposed robotic catheter system can provide useful motion and force feedback for vascular surgery.