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| 1 | Error Analysis on the Positioning Accuracy of a Pneumatic Vibration Isolator显示文摘A method of error analysis on the positioning accuracy of a pneumatic vibration isolator was proposed.First,the necessity of positioning accuracy was studied,in addition to the key factors associated with positioning accuracy.These analyses indicated that the positioning accuracy of the pneumatic vibration isolator was mainly attributed to the position error of the push button and the gap between the spindle and valve stem.Second,the error model of the positioning accuracy of the pneumatic vibration isolator was established through geometric simplification and geometric calculation.There are different methods used to calculate the position error of the push button for the different valves.Finally,an example analysis evaluating the impact of a specific two-position three-way valve on the positioning accuracy was given by means of error distribution.Experimental results validated the accuracy of the error model and the example analysis.This error model can be used to guide the structural parameter optimization design according to the requirements for positioning accuracy. | Qiang Yu Dengfeng Xu Yu Zhu Gaofeng Guan Qiang L | 2019 | Journal of Beijing Institute of Technology2019，28，2： | 0 |
| 2 | Digital Noah's Ark:last chance to save the endangered species显示文摘Global biodiversity is undergoing dramatic loss,mostly due to anthropogenic actions and climate change.Around 2.3seed plants died out each year in the past 2.5 centuries(Humphreys et al.,2019).Current species extinction rates are about 1,000 times the likely background rate of extinction(Pimm et al.,2014). | Fuwen Wei Guangping Huang Dengfeng Guan Huizhong Fan Wenliang Zhou Depeng Wang Yibo Hu | 2022 | Science China(Life Sciences)2022，65，11： | 0 |
| 3 | Energy Cycle Insingle Degree of Freedom Conservative Vibration Isolation Systems显示文摘To obtain a longer natural period in single degree of freedom(SDF) conservative vibration isolation systems, many scholars have proposed different methods. This paper uncovers a clockwise energy cycle existing in a mass-spring system, in which the potential energy and kinetic energy convert with each other, and the natural period is determined by the magnitude of the energy cycle. Compared to water flow inside a pipe, the previous methods can be consolidated into two methods to make the energy cycle narrower;one is to optimize the parameters directly, the other is to indirectly add an anticlockwise energy cycle to the original one. The anticlockwise energy cycle has the characteristic of gravitational potential energy or elastic potential energy that reduces with displacement. The highly abstract method can provide a better optimization tool to design a practice system. | Gaofeng Guan Dengfeng Xu Yu Zhu Qiang Yu Qiang Li | 2019 | Journal of Beijing Institute of Technology2019，28，3： | 0 |
| 4 | Design and Analysis of a Horizontal Quasi-Zero Stiffness Vibration Isolator by Combining Rolling-Ball and Disk Springs in Parallel显示文摘Combining disk springs having negative stiffness with a rolling-ball in parallel is proposed in this paper. It is used to reduce the system stiffness and the positioning error in a non-ideal environment.The characteristics of a disk spring are analyzed. The dynamic equation of its motion has been obtained based on Newton's second law. After definition of a error margin,the dynamic equation of the motion can be treated as a Duffing oscillator,and the influences of non-dimensional parameters on the stiffness and transmissibility are studied. The natural frequency and transmissibility are achieved in a linearization range,where the ratio of linear to nonlinear items is small enough.The influence of mass ratio and non-dimensional parameters on natural frequency are analyzed. Finally,a comparison of numerical example demonstrates that the QZS system can realize a lower stiffness within an increased range. | Gaofeng Guan Dengfeng Xu Yu Zhu Qiang Li Qiang Yu | 2017 | Journal of Beijing Institute of Technology2017，26，4： | 0 |
| 5 | Association between high body mass index and prognosis of patients with early-stage breast cancer: A systematic review and meta-analysis显示文摘Background:A high body mass index(BMI)can indicate overweight or obesity and is a crucial risk factor for breast cancer survivors.However,the association between high BMI and prognosis in early-stage breast cancer(EBC)remains unclear.We aimed to assess the effects of high BMI on the prognosis of patients with EBC.Methods:The PubMed,Embase,and Cochrane Library databases and proceedings of major oncological conferences related to the effects of BMI on the prognosis of breast cancer were searched up to November 2021.Fixedand random-effects models were used for meta-analyses.Pooled hazard ratios(HRs)and 95%confidence intervals(CIs)for disease-free survival(DFS)and overall survival(OS)were extracted from the included literature.Results:Twenty retrospective cohort studies with 33,836 patients with EBC were included.Overweight patients had worse DFS(HR:1.16,95%CI:1.05-1.27,P=0.002)and OS(HR:1.20;95%CI:1.09-1.33,P<0.001).Obesity also had adverse effects on DFS(HR:1.17,95%CI:1.07-1.29,P=0.001)and OS(HR:1.30,95%CI:1.17-1.45,P<0.001).Likewise,patients with high BMI had worse DFS(HR:1.16,95%CI:1.08-1.26,P<0.001)and OS(HR:1.25,95%CI:1.14-1.39,P<0.001).In subgroup analyses,overweight had adverse effects on DFS(HR:1.11,95%CI:1.04-1.18,P=0.001)and OS(HR:1.18,95%CI:1.11-1.26,P<0.001)in multivariate analyses,whereas the relationship that overweight had negative effects on DFS(HR:1.21,95%CI:0.99-1.48,P=0.058)and OS(HR:1.39,95%CI:0.92-2.10,P=0.123)was not statistically significant in univariate analysis.By contrast,obesity had adverse effects on DFS(HR:1.21,95%CI:1.06-1.38,P=0.004 and HR:1.14,95%CI:1.08-1.22,P<0.001)and OS(HR:1.33,95%CI:1.15-1.54,P<0.001 and HR:1.23,95%CI:1.15-1.31,P<0.001)in univariate and multivariate analyses,respectively.Conclusions:Compared with normal weight,increased body weight(overweight,obesity,and high BMI)led to worse DFS and OS in patients with EBC.Once validated,these results should be considered in the development of prevention programs. | Zhoujuan Li Guoshuang Shen Mingqiang Shi Yonghui Zheng Yumei Guan Yuanfang Xin Miaozhou Wang Fuxing Zhao Dengfeng Ren Jiuda Zhao | 2023 | Cancer Pathogenesis and Therapy2023，1，3： | 0 |
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