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变速切削系统振动频率的变化特征 总被引:1,自引:0,他引:1
本文主要讨论变速切削系统中颤振频率随机床主轴转速变化的规律。理论分析和试验结果都证明在变速切削中颤振频率随转速呈分段线性锯齿状变化。试验在立式铣床和普通车床上进行。 相似文献
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本文介绍在铀矿床工业指标制定中,对未来矿山开采设计方案及经济计算参数几千问题的分析,以利于合理的制定铀矿床工业指标,为铀矿冶企业技术改造,在建企业修改设计和为选择新建企业提供决策依据,进而使铀矿冶企业提高经济效益。 相似文献
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采用热压法制备出二层锆钛酸铅(PZT)/聚偏氟乙烯(PVDF)与1层Tb0.28Dy0.72Fe2(Terfenol-D)/PVDF叠层结构的三元复合磁电材料,研究了不同PVDF含量,以及不同层厚比tp/L对样品的介电常数、介电损耗、电阻率、谐振频率以及磁电转换系数αE33,αE31的影响规律,结果显示PVDF的含量和层厚比都存在最佳值(最佳值出现在产0.5,tp/L=2/7),并且在这个最佳值处,磁电转换系数达到最大。 相似文献
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Cheng Jiaqi Gong Junyi Yue Shuai Jiang Yao Hou Xiangjun Ma Jianjun Yao Yali Jiang Cairong 《Journal of Applied Electrochemistry》2021,51(8):1175-1188
Journal of Applied Electrochemistry - La-doped titanate materials have been widely investigated as alternative Ni-free anodes for solid oxide fuel cells (SOFCs). In this study, La0.4Sr0.6TiO3 (LST)... 相似文献
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Yue Zhi Junyi Che Haofang Zhu Rui Liu Yuanjin Zhao 《Advanced functional materials》2023,33(43):2304353
In diabetic wound healing, M1 macrophage accumulation and elevated inflammation are prevalent issues. Intelligent delivery systems that can sustainably release antioxidizing and anti-inflammatory ingredients are expected for effective wound healing. Herein, a novel glycyrrhetinic acid (GA) liposomes encapsulated microcapsules delivery system that has desired features for inflammatory wound repair is presented. As the bacteria could break down the alginate shells, the GA liposomes could be controllably released from the microcapsules, which promotes M2 macrophage polarization and regulate their responses in the inflammatory wound microenvironment. Based on these, it is demonstrated that the GA liposomes encapsulated microcapsules delivery system exhibits an anti-inflammatory and immunomodulatory effect for diabetic wound healing in a full-thickness defect model in diabetic rats. These results indicate that the immunomodulatory capabilities of the microcapsules can be unitized for efficient wound repair, and such a delivery system is valuable for clinical wound healing applications. 相似文献
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能源转型背景下,新型电力系统中高比例可再生能源和高比例电力电子设备接入的特征将深刻改变电网形态和运行特性,对仿真理论研究和先进仿真工具研发提出了新的需求。文中梳理了现有仿真软件、仿真体系在应对新型电力系统稳定特性变化、仿真分析时空尺度和跨度增大,以及电力系统数字化发展过程中电网智能分析运行控制体系构建3个层面上的需求与挑战。分析现有仿真技术的特性,指出当前仿真工具存在的不足。最后,理清仿真工具发展趋势,提出新型电力系统仿真技术框架,并就目前仿真工具需要关注的潜在技术发展要点进行展望。 相似文献
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Mental workload is considered to be strongly linked to human performance, and the ability to measure it accurately is key for balancing human health and work. In this study, brain signals were elicited by mental arithmetic tasks of varying difficulty to stimulate different levels of mental workload. In addition, a finite impulse response (FIR) filter, independent component analysis (ICA), and multiple artifact rejection algorithms (MARAs) were used to filter event-related potentials (ERPs). Then, the data consisting of ERPs, subjective ratings of mental workload, and task performance, were analyzed through the use of variance and Spearman’s correlation during a simulated computer task. We found that participants responded faster and performed better in the easy task condition, followed by the medium and high-difficulty conditions, which verifies the validity of the ERP filtering. Moreover, larger P2 and P3 waveforms were evoked as the task difficulty increased, and a higher task difficulty elicited a more enhanced N300. Correlation analysis revealed a negative relationship between the amplitude of P3 and the subjective ratings, and a positive relationship between the P3 amplitude and accuracy. The results presented in this paper demonstrate that a combination of FIR, ICA, and MARA methods can filter ERPs in the non-invasive real-time measurement of workload. Additionally, frontocentral P2, N3, and parietal P3 components showed differences between genders. The proposed measurement of mental workload can be useful for real-time identification of mental states and can be applied to human–computer interaction in the future. 相似文献