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Q. Yuan(위안 취안),J. Suhr(서종환) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월
Future-proof materials can be optimally designed based on advanced additive manufacturing techniques, and additive manufacturing is an exciting manufacturing technique that can fabricate complex structures in a layer-by-layer build-up method. Rigid closed cellular materials with closed irregular pores are often used as structural thermal insulation materials because of their good mechanical strength and thermal properties. Specifically, additive manufactured closed-cellular materials can achieve high thermal management performance by accurately controlling the distribution and geometrical parameters of closed pores. In addition, Bayesian optimization is an emerging approach to optimize objective functions that are high cost to be evaluated. Therefore, this work explored a combination of a sequential Bayesian optimization and finite element method (FEM) to design a new additive manufactured closed-cellular structure with low effective thermal conductivity (ETC). The heat transfer among closed-cellular structures is simulated by FEM, and the effect of distribution and geometrical parameters of closed pores on ETC of the closed-cellular structures was analyzed. A new thermal insulated closed-cellular material was designed at a low computational cost. This work provides a solution for material structure design with huge design space and high-experimental costs.
Q. YUAN,Y. LI,S. XING,Y. LV 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.6
In actual traffic accidents, a phenomenon is observed where the speedometer needle jams at a certain value after the impact. Using the residual reading of the speedometer, we may infer the approximate vehicle speed while the impact occurred. Based on the function of typical speedometer, the impact characteristic and damage mechanism of vehicles, this paper describes the research of how the speedometer needle stops during accidents and its failure modes. According to the statistics of thirty specific traffic accident cases containing residual speedometer needle readings, we obtain and summarize the characteristics and rules concerning the accidents and the related information. Furthermore, a typical accident case is analyzed by in-depth level. The results reveal that for the accident vehicles with electronic speedometers, there is a strong correlation between the residual reading of the speedometer and the real vehicle impact speed. The conclusions may provide a new effective method and reference for accident reconstruction and the estimation of vehicle speed.
SPATIAL DISTRIBUTION OF THE SPIN VECTORS OF THE DISK GALAXIES IN THE VIRGO CLUSTER
YUAN Q. R.,HU F. X.,HE X. T. The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1
In order to investigate the spatial orientation of the spin vectors of galaxies in the Virgo cluster, we carried out a detailed identification of all the certain and possible member disk galaxies with four UK Schmidt Telescope (UKST) III a-j direct plates digitized by the Automated Plate Measuring System (APM). As a result, a relatively large and complete database with no selection effect of the member galaxies has been established. We provide the APM measured values of the position angle (P.A.) and diameters at the isophotal level of 24.5 $m_j / arcsec^2$. Based on this newly generated database, an initial study on the spatial orientation of the spin vectors of galaxies in the Virgo cluster is shown.
Proton Shell Evolution below Sn132 : First Measurement of Low-Lying β -Emitting Isomers in Ag123,125
Chen, Z. Q.,Li, Z. H.,Hua, H.,Watanabe, H.,Yuan, C. X.,Zhang, S. Q.,Lorusso, G.,Nishimura, S.,Baba, H.,Browne, F.,Benzoni, G.,Chae, K. Y.,Crespi, F. C. L.,Doornenbal, P.,Fukuda, N.,Gey, G.,Gernhä American Physical Society 2019 Physical Review Letters Vol.122 No.21
Q. Ma,M. Yue,W. C. Lv,H. G. Zhang,X. K. Yuan,D. T. Zhang,X. F. Zhang,J. X. Zhang,X. X. Gao 한국자기학회 2016 Journal of Magnetics Vol.21 No.1
In the present study, bulk anisotropic nanocrystalline SmCo₅ magnets were prepared by hot deformation. The effect of deformation temperature on the texture and magnetic properties are presented, based on which the mechanism of plastic deformation and texture formation during the hot deformation process is discussed. Our analyses reveal that deformation temperature is one of the most important parameters that determine the texture of SmCo5 grains. We suggest that diffusion creep plastic deformation occurs during hot deformation, which is very sensitive to the energy gain provided by an increase in temperature.
Thermal analysis and optimization of the new ICRH antenna Faraday Screen in EAST
Q.C. Liang,L.N. Liu,W. Zhang,X.J. Zhang,S. Yuan,Y.Z. Mao,C.M. Qin,Y.S. Wang,H. Yang Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7
In Experimental Advanced Superconducting Tokamak (EAST) experiments, to achieve long pulse and high-power ICRH system operation, a new kind of ICRH antenna has been designed. One of the most critical factors in limiting the operation of long pulse and high power is the intense heat load in the front face of the ICRH antenna, especially the Faraday Screen (FS). Therefore, the cooling channels of FS need to be designed. According to thermal-hydraulic analysis, the FS tubes are divided into several groups to achieve more excellent water cooling capability. The number of series and parallel tubes in one group is chosen as six. This antenna went into service in the spring of 2021, and it is delightful that the temperature distribution of the FS tube is below 400 ℃ in 14.5 s and 1.8 MW ICRH system operation. However, the active water-cooling design was not carried out on the upper and lower plates of FS, which led to severe ablations on that region under long pulse and high power operation, and the temperature is up to 800. Therefore, the upper and lower side plates of the FS were designed with water cooling based on thermal-hydraulic analysis. During the 2022 winter experiments, the temperature of ICRH antenna FS was lower than 400 in the pulse of 200s and the power of 1 MW operation.
Modification of the degree of 4-O-methylation of secondary wall glucuronoxylan
Yuan, Y.,Teng, Q.,Lee, C.,Zhong, R.,Ye, Z.H. Elsevier Scientific Publishers Ireland Ltd 2014 Plant science Vol.219 No.-
Plant secondary walls are the major constituent of plant biomass targeted for second-generation biofuel production. Therefore, a thorough understanding of how secondary walls are constructed is critical for a better utilization of plant biomass for biofuel production. One of the major components in secondary walls is xylan, which is composed of a linear chain of β-1,4-linked xylosyl residues. In Arabidopsis, about 10% of xylosyl residues in xylan are substituted with glucuronic acid (GlcA), of which 60% are methylated at O-4. By contrast, all of the GlcA substituents in Populus xylan are methylated at O-4. It is not known how the degree of GlcA methylation in xylan is controlled. In this report, we demonstrated that simultaneous T-DNA knockout mutations of the three glucuronoxylan methyltransferase (GXM) genes, GXM1, GXM2, and GXM3/GXMT1, which are specifically expressed in secondary wall-forming cells, led to a complete loss of GlcA methylation in xylan in Arabidopsis stems. Overexpression of GXM2 and GXM3 in wild-type Arabidopsis resulted in an up to 5-fold increase in glucuronoxylan methyltransferase activity and as a result, up to 90% of the GlcA side chains in xylan were methylated as opposed to 60% seen in the wild type. The increased degree of GlcA methylation in xylan had no discernable effects on cell wall sugar composition and lignin monomer composition. These results reveal that the activities of GXM1, GXM2 and GXM3 are responsible for all of the GlcA methylation in xylan in Arabidopsis stems and that the degree of GlcA methylation in xylan can be modified by altered expression of GXMs.
Optimal Harvest-Use-Store Design for Delay-Constrained Energy Harvesting Wireless Communications
Yuan, Fangchao,Jin, Shi,Wong, Kai-Kit,Zhang, Q.T.,Zhu, Hongbo The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.6
Recent advances in energy harvesting (EH) technology have motivated the adoption of rechargeable mobile devices for communications. In this paper, we consider a point-to-point (P2P) wireless communication system in which an EH transmitter with a non-ideal rechargeable battery is required to send a given fixed number of bits to the receiver before they expire according to a preset delay constraint. Due to the possible energy loss in the storage process, the harvest-use-and-store (HUS) architecture is adopted. We characterize the properties of the optimal solutions, for additive white Gaussian channels (AWGNs) and then block-fading channels, that maximize the energy efficiency (i.e., battery residual) subject to a given rate requirement. Interestingly, it is shown that the optimal solution has a water-filling interpretation with double thresholds and that both thresholds are monotonic. Based on this, we investigate the optimal double-threshold based allocation policy and devise an algorithm to achieve the solution. Numerical results are provided to validate the theoretical analysis and to compare the optimal solutions with existing schemes.