http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Zinan Wang (검색결과 6 건)
- 무료
- 기관 내 무료
- 유료
-
Zinan Wang,Ke Zhang,Zhan Wang,Xiaotian Bai,Qingyuan Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
The vibration of ceramic motorized spindle determines the machining quality of CNC machine tools. The dynamic characteristics of a motorized spindle were explored under the influence of interference fit and thermal displacement. Using heat transfer theory and bearing Harris theory, the temperature field model of motorized spindle was established, which aims to find the relationship of thermal displacement and interference. In addition, the dynamic and thermal factors were coupled to the dynamic model of the ceramic motorized spindle rotor system, of which the variation rules of bearing stiffness and rotor vibration characteristics were calculated and analyzed. The accuracy of the motorized spindle rotor system dynamic model was verified by experiments. The results show that the interference fit of shaft and bearing decreases with the rotating speed increase under the combined influence of centrifugal force, load and thermal displacement. The vibration was calculated by the dynamic model of motorized spindle rotor system considering dynamic and thermal factors. The maximum error was 3.9 %, which is well consistent with the experimental results. The dynamic characteristics of ceramic motorized spindle can be improved by appropriately increasing the degree of interference tightness at high speed.
-
Research for the bearing fit effect on the vibration characteristics of spindle rotor-bearing system
Zhan Wang,Siyang Chen,Wenzhi He,Zinan Wang,Zhongxian Xia 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12
Spindle bearing fits mainly include interference fit of inner ring and clearance fit of outer ring, which directly affect the vibration characteristics of spindle rotor-bearing system. In this paper, the influence of spindle bearing inner and outer ring fits on bearing support stiffness is firstly studied. Considering the spindle bearing inner and outer ring fits, a dynamic model of spindle rotor-bearing system is established. Then, the analysis methods of bifurcation and time domain are used to perform simulation analysis. The influence of bearing fit on the vibration characteristics of rotor system is researched. Lastly, at different rotating speeds, bearing fits experiments are conducted on built motorized spindle test platform, which verifies the correctness of the dynamic model. The results show that the influence of bearing fit on vibration is nonlinear. The influence of clearance fit on vibration is smaller, when the clearance fit value of bearing outer ring is about 4-6 μm. The vibration characteristics of rotor are more sensitive to the clearance fit of bearing outer ring than the interference fit of bearing inner ring. The research work provides an important theoretical basis for the optimal of spindle bearing assembly.
-
Energy trapping of thickness-extensional modes in thin film bulk acoustic wave resonators
Zinan Zhao,Zhenghua Qian,Bin Wang,Jiashi Yang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.7
We perform a theoretical analysis on a rectangular trapped-energy piezoelectric resonator operating with thickness-extensional modesof a thin zinc oxide film on a silicon layer. The driving electrode covers the central part of the resonator only. The two-dimensional scalardifferential equation for such a structure derived by Tiersten and Stevens is employed which can describe in-plane mode variations. Avariational formulation is developed which provides the theoretical foundation for the Ritz method used in our analysis. Free vibrationfrequencies and modes are obtained and examined. Modes with vibrations trapped under the driving electrode are found. An approximationused to obtain the classical result of the resonator by Tiersten and Stevens, i.e., the neglect of the four corner regions of the resonator,is removed in our variational analysis. It is shown that their approximation causes a frequency difference on the order of dozens of partsper million for the fundamental thickness-extensional operating mode, quite significant in resonator design and operation.
-
Maltol Inhibits Apoptosis of Human Neuroblastoma Cells Induced by Hydrogen Peroxide
Yang, Yang,Wang, Jian,Xu, Caimin,Pan, Huazhen,Zhang, Zinan Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.2
To analyze the effect of Maltol on the apoptosis of Human Neuroblastoma Cells (SH-SY5Y) treated by free radical which was generated from Hydrogen Peroxide ($H_2O_2$), flow cytometry analysis on Phosphatidylserine (PS) inverting percentage was applied to determine the apoptosis. MTT (3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assay was employed to analyze the cell viability. DNA electrophoresis was used to detect DNA fragmentation. Moreover intracellular calcium of concentration ($[Ca^{2+}]_i$) was measured by fluorescence emission. Flow cytometry analysis on the function of mitochondria and Western blto analysis of NF-${\kappa}B$. The results showed that the pretreatment with maltol for 2 hours could prevent the $H_2O_2$-induced apoptosis. Maltol could reduce the inverting percentage of PS, DNA fragmentation and $[Ca^{2+}]_i$, and enhance the cellular function of mitochondria. NF-${\kappa}B$ activated by $H_2O_2$ is reduced. The experiments suggest that maltol could effectively inhibit the apoptosis induced by $H_2O_2$. As a novel anti-oxidant, maltol is a new promising drug in protecting the neurological cells from the damage by free radical.
-
Metabolic Engineering of Vitamin C Production in Arabidops
Ling Xiao,Ying Xiao,Zinan Wang,Hexin Tan,Kexuan Tang,Lei Zhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4
Vitamin C (L-ascorbic acid, AsA) is a compound which provides major nutritional value, both for plants and humans. In this study, three distinct metabolic engineering strategies, including overexpression of biosynthesis enzyme, suppression of catabolism enzyme and switching the sub-cellular localization of compartment enzyme, were employed to enhance the production of AsA in Arabidopsis thaliana. The results showed that (1) overexpression of L-Galactose-1-P Phosphatase (GalPPase) enhanced AsA content to 3.96 μmol/g FW, which was 1.6-fold more than that in their wild-type (WT) counterparts; (2) RNAi suppression of ascorbate oxidase (AO) resulted in a significant increase of AsA accumulation (0.86 μmol/g FW) in apoplast; (3) both mitochondrion-target and none-target overexpression of L-Galactose dehydrogenase (GalDH) did not significantly promote AsA production compared with WT (1.96 μmol/g), however a dramatic enhancement was observed following infiltration with L-galactono-1, 4-lactone (L-GalL), both in transgenic and WT plants. The best line produced AsA with the content of 3.90 μmol/g FW, which was about 2-fold of that in the untreated control (1.99 μmol/g FW). This study provides new strategies including GalPPase overexpression, AO suppression as well as L-GalL feeding for modern breeding aimed at stimulating the AsA content in plants.
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
