Search

Objective A finite element model of metro vehicle air compressor frame is established and verified through modal testing and vibration testing. It is found that the vertical bending modal frequency of the dryer frame coincides with motor harmonic frequency and the vibration isolation rate is relatively low. Under the premise of meeting modal frequency and vibration isolation rate requirements, a structural optimization design of air compressor frame is carried out by integrating finite element method and optimization techniques. Method Taking the thickness of the air compressor frame as the optimization variable, DOE (design of experiment) is firstly carried out to obtain different samples of air compressor frame, then an approximate model of air compressor frame is established using the Moving Least Squares method. Based on this approximate model, with vertical first-order bending modal frequency of the frame, vertical bending modal frequency of dryer frame and vibration isolation rate as optimization objectives, an optimization design is performed using the adaptive response surface method to obtain the optimal scheme of frame parameters. Result & Conclusion Results show that, compared to before optimization, the vertical first-order bending and the dryer frame vertical bending modal frequencies after optimization are both more than 3.0 Hz different from the rail excitation frequency (typically 15.0 Hz), motor rotation fundamental frequency (24.5 Hz), and harmonics; reaching the optimal avoidance of resonance conditions, and the vibration isolation rate can be increased by 20% to 25%, while the total mass only increases by 6%.

Background and purpose: According to the 2020 global cancer burden data of the International Agency for Research on Cancer (IARC), breast cancer has replaced lung cancer as the most common type of cancer worldwide. The aim of this study was to conduct a bibliometric and visual analysis of breast reconstruction related research in China and abroad published in the past 5 years, to understand the research status and development trend in this field, to discuss the focus of research in different countries and different disciplines, and to provide reference for other researchers. Methods: Relevant literatures about breast reconstruction were retrieved from the Web of Science Core Collection. The VOS viewer 1.6.15 software was used to extract the authors, countries, institutions and keywords to generate network maps of high-yield authors, institutions and high-frequency keywords clustering network. Results: A total of 4 815 documents meeting the requirements were retrieved, which showed an upward trend in the past five years. Regarding the discipline, 838 documents (17.40%) were published by breast surgery and Cancer Surgery, 3 308 (68.70%) were published by plastic surgery, and 669 (13.90%) were jointly published by both types of researchers. There were differences in the disciplines of the main authors between China and abroad. In China, authors from breast surgery published a larger proportion of documents (138, 44.52%), while the number of documents published by authors of plastic surgery (129, 44.52%) and the joint publication of both types of authors (43, 13.87%) was relatively small. However, foreign documents mainly came from authors of plastic surgery (74.74%). There were more cooperative groups (155) formed by major foreign authors, and more frequent joint publishing between groups, while Chinese authors formed only 16 cooperative groups with less cooperation. Authors from breast surgery focused more on oncology-related issues in breast reconstruction, while in plastic surgery, more attentions were paid on autologous tissue reconstruction. Conclusion: Breast reconstruction has gradually attracted the attention of Chinese and foreign researchers. Compared with foreign countries, there were problems such as lack of high-quality research and less cooperative research in China. There were differences in the research focus of breast reconstruction between China and abroad, which was mainly related to the differences in the disciplines of researchers.

Due to a series of complications associated with traditional axillary lymph node dissection, sentinel lymph node biopsy has now replaced axillary lymph node dissection as the standard axillary staging procedure for patients with negative axillary lymph nodes in both domestic and international clinical practice. With the increased application of breast-conserving surgery and the subsequent increase in the number of patients with ipsilateral breast recurrence after breast-conserving surgery, the appropriate axillary evaluation of such patients has become a new topic of clinical concern, and the application of repeat sentinel lymph node biopsy has become one of the focal points of this topic. It has been shown that repeat sentinel lymph node biopsy is a feasible and safe method for axillary evaluation in patients with ipsilateral breast tumor recurrence after breast-conserving surgery, and that treatment can be adjusted for some patients depending on axillary lymph node status. However, due to the relative lack of studies on the prognostic impact of repeat sentinel lymph node biopsy results and with the development of non-invasive screening techniques, the necessity of repeat sentinel lymph node biopsy in this group of patients remains controversial and needs to be explored in future high-quality prospective trials. This article compiled and summarized the previous literature related to repeat sentinel lymph node biopsy, and focused on its feasibility, safety and clinical application value for clinical reference.