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Effect of Silicon Content in Al–Si Welding Wire on Mechanical Properties of Al/Cu Laser Welded Joint
Peifeng Wang,Fei Liu,Lihui Pang,Zhe Guo 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.5
In this study, the laser welding of Al/Cu using Al–Si welding wires was analyzed. The impact of varying silicon content in the Al–Si welding wires (0%, 12%, 16%, 20%) and laser power settings ranging from 900 to 1050W in 50W increments on the phase composition, microstructure, and mechanical properties of the weld joints was investigated. It was observed that a silicon-rich interface layer formed near the copper side of the weld seam. This formation led to grain orientation and a significant reduction in grain size. As the Si content increased, the morphological structure transformed from irregularly layered dendritic to regularly oriented dendritic, and ultimately to equiaxed crystals. X-ray diffraction analysis of the weld seam revealed the presence of main intermetallic phases, including Al2Cu. It was concluded that the highest tensile strength, reaching 85.1 MPa, was achieved using an AlSi12 weld filler at a power of 900W.
Li Tingting,Cao Shunwang,Wang Yi,Xiong Yujuan,He Yuting,Ke Peifeng,Huang Xianzhang 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1
Background: A small shift in high-sensitivity cardiac troponin T (hs-cTnT) assays can lead to different result interpretation and consequent patient management. We explored whether a small bias could be detected using conventional internal quality control (QC) procedures, evaluated the performance of moving average (MA)-based QC procedures, and proposed a new QC procedure based on the moving rate (MR) of positive patient results of hs-cTnT assays. Methods:The ability of conventional QC to detect a 5 ng/L bias was examined using the13s/ 22s/R4s multi-rule procedure as deviation rules.We developed MA and MR procedures for the hs-cTnT assay using eight months of patient data. The performance of different MA or MR procedures was investigated by calculating the median number of patient samples affected until a bias introduced into the dataset was detected (MNPed). After comparing the MNPed across different procedures, we selected an optimal MA or MR procedure for validation. Validation graphs were plotted using the minimum, median, and maximum number of results affected until bias detection. Results: Our conventional QC procedures could not detect a positive bias of 5 ng/L. When a positive bias was introduced, MNPed was much higher using MA than using MR, with cut-off values of 5 ng/L and 14 ng/L, respectively. MR validation charts for optimal procedures provided insight into the MR performance. Conclusions: The MR procedure could detect different errors with few false alarms. In the hs-cTnT assay, the MR procedure with a smaller cut-off value outperformed MA and conventional QC procedures for small bias detection.
Liu Yize,Qiu Guanzhen,Luo Yinzhou,Li Shanshan,Xu Yeqiu,Zhang Yuanzhuang,Hu Jiayuan,Li Peifeng,Pan Hai,Wang Yong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
As the most prevalent bone tumor in children and adolescents, the pathogenesis and metastasis of osteosarcoma (OS) remain largely unclear. Here, we investigated the expression and function of a novel circular RNA (circRNA), circROCK1-E3/E4, which is back-spliced from exons 3 and 4 of Rho-associated coiled-coil containing protein kinase 1 (ROCK1) in OS. We found that circROCK1-E3/E4, regulated by the well-known RNA-binding protein quaking (QKI), was downregulated in OS and correlated with unfavorable clinical features of patients with OS. Functional proliferation and cell motility assays indicated that circROCK1-E3/E4 serves as a tumor suppressor in OS cells. Mechanistically, circROCK1-E3/E4 suppressed proliferation and migration by upregulating phosphatase and tensin homolog (PTEN) through microRNA-532-5p (miR-532-5p) sponging. In the constructed nude mouse model, circROCK1-E3/E4 inhibited tumor growth and lung metastasis in vivo. This study demonstrates the functions and molecular mechanisms of circROCK1-E3/E4 in the progression of OS. These findings may identify novel targets for the molecular therapy of OS.