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Assessment of electronic and mechanical properties for nano-adhered aluminum alloy sheet
Zemin Liu(류택민),Dong-Ho Bae(배동호) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In this paper, a new nano-adhesive which has been improved the conventional epoxy resin widely using in automobile industries was introduced. This nano-adhesive is organically composited with multi-walled carbon nano-tubes (MWCNT) (from 1%-3% by weight) as reinforcement. In order to optimize its quality and performance, electric and mechanical characteristics of the joints taking account the geometrical parameters of bonded layer into were assessed. The electric resistance of the nano-adhesive decreased with increase of the nano-tube weight percentage, and decrease of the thickness of the bonded layer. And in order to evaluate the overloading behaviors of the nano-adhesives and compare the results with the original epoxy resin, tensile tests were conducted on different overlapped length of the bonded joints. From the results, the ultimate tensile strength remarkably increased at 2% weight percentage. Also surface treatment condition of the plates affected the ultimate tensile strength of the bonded joint.
Design and control method of a hydraulic power unit for a wheel-legged robot
Zemin Cui,Xuewen Rong,Yibin Li 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4
For a hydraulic wheel-legged robot (WLR), it is essential to have a powerful and lightweight power supply. In this paper, a compact hydraulic power unit (HPU) is developed, and a control method to reduce the energy consumption of the robot is proposed. To achieve a high jump of the robot, an accumulator serves as an auxiliary oil source. To reduce the pressure loss caused by the throttle of the servo valve, we control the pressure of the system through load sensing. Simulation results showed that the power of the HPU using the accumulator could be amplified 3.3 times. The experimental results obtained through physical testing showed that the power consumption of the system using the load sensing mechanism was reduced by more than 50 %.
Yan Liu,Zemin Xu,Men Tang,Yishuo Zhang,Shaofeng Zhang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.2
In order to solve the particle circulation problem of external circulation fluidized bed evaporator, a new particle circulation device was developed, and a cold experiment device was set up for reference to the principle of gassolid circulating fluidized bed U-loop seal valve. The adjustment characteristics of the particle circulation device were studied experimentally. The effects of different flow combinations on pressure drop, particle circulation rate and particle volume fraction of heat exchange tube were investigated when the main flow and any auxiliary flow of the sealing valve were combined. It was found that when the main flow rate is constant, the pressure drop of the heat exchange tube increases with the increase of the auxiliary flow rate, and the pressure drop trend is stable when the main flow and loose flow are combined. The flow rate of particle circulation can be adjusted by adjusting the flow rate of any auxiliary flow alone, and fluidized flow has the strongest ability to regulate the particle circulation rate. The amplitude of the power spectral density of the pressure differential fluctuation signal is related to the particle circulation rate and volume fraction, so the flow state in the pipe can be studied by this method.
Numerical investigation of the critical heat fl ux in a 5 × 5 rod bundle with multi-grid
Wei Liu,Zemin Shang,Shihao Yang,Lixin Yang,Zihao Tian,Yu Liu,Xi Chen,Qian Peng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5
To improve the heat transfer efficiency of the reactor fuel assembly, it is necessary to accurately calculatethe two-phase flow boiling characteristics and the critical heat flux (CHF) in the fuel assembly. In thispaper, a Eulerian two-fluid model combined with the extended wall boiling model was used tonumerically simulate the 5 5 fuel rod bundle with spacer grids (four sets of mixing vane grids and foursets of simple support grids without mixing vanes). We calculated and analyzed 11 experimental conditions under different pressure, inlet temperature, and mass flux. After comparing the CHF and thelocation of departure from the nucleate boiling obtained by the numerical simulation with the experimental results, we confirmed the reliability of computational fluid dynamic analysis for the prediction ofthe CHF of the rod bundle and the boiling characteristics of the two-phase flow. Subsequently, weanalyzed the influence of the spacer grid and mixing vanes on the void fraction, liquid temperature, andsecondary flow distribution. The research in this article provides theoretical support for the design of fuelassemblies
Jian Zhang,Zemin Li,Fan Chen,Hui Liu,Hua Wang,Xiang Li,Xianguo Liu,Jianru Wang,Zhaomin Zheng 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-
The objective of this study was to investigate the regulatory effects of TGF-β1 on CCL3/4 expression and inflammation-related pain during intervertebral disc degeneration (IVDD). TGF-β1 and CCL3/4 expression patterns in different degenerative human nucleus pulposus (NP) tissues were measured by qPCR and immunohistochemistry (IHC), and the effects of TGF-β1 on CCL3/4 expression were measured by qPCR, ELISA and immunofluorescence. The roles of NF-κB and MAPK in TGF-β1-mediated CCL3/4 promoter activity were studied using siRNAs, western blotting and qPCR. After establishing an IVDD rat model in vivo, we administered intradiscal injections of TGF-β1. The effects of TGF-β1 on IVDD were determined by MRI and histological analyses, and the effects of TGF-β1 on dorsal root ganglion (DRG) inflammation and pain development were determined by IHC staining and pain-behavior testing, respectively. TGF-β1 and CCL3/4 expression was elevated in degenerative NP tissue. CCL4 expression was significantly inhibited by TGF-β1 treatment. Pharmacological inhibition or siRNA knockdown of the ERK1/2 signaling attenuated TGF-β1-mediated suppression of CCL4 expression. In vivo, TGF-β1 injection inhibited the development of degenerative features in the IVDD model. Moreover, TGF-β1 prevented the inflammatory response and pain development. The results of this study show that TGF-β1 downregulates CCL4 expression through ERK1/2 signaling activation in NP cells. Furthermore, TGF-β1 can prevent degenerative processes, inhibit inflammatory responses in the DRG and prevent pain development in the IVDD rat model. The results of this study indicate that TGF-β1 may represent a therapeutic target for the control of inflammation-related pain associated with IVDD.
Co-saliency Detection Based on Superpixel Matching and Cellular Automata
( Zhaofeng Zhang ),( Zemin Wu ),( Qingzhu Jiang ),( Lin Du ),( Lei Hu ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.5
Co-saliency detection is a task of detecting same or similar objects in multi-scene, and has been an important preprocessing step for multi-scene image processing. However existing methods lack efficiency to match similar areas from different images. In addition, they are confined to single image detection without a unified framework to calculate co-saliency. In this paper, we propose a novel model called Superpixel Matching- Cellular Automata (SMCA). We use Hausdorff distance adjacent superpixel sets instead of single superpixel since the feature matching accuracy of single superpixel is poor. We further introduce Cellular Automata to exploit the intrinsic relevance of similar regions through interactions with neighbors in multi-scene. Extensive evaluations show that the SMCA model achieves leading performance compared to state-of-the-art methods on both efficiency and accuracy.