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Shear Thickening Polishing of Black Lithium Tantalite Substrate
B. H. Lyu,Q. Shao,W. Hang,S. H. Chen,Q. K. He,J. L. Yuan 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9
To achieve high efficiency in the polishing process to obtain a high surface quality of black LT substrate (a kind of soft brittle material), shear thickening polishing (STP), which is a “gentle” finishing process developed in recent years, was employed in this study. The influence of three key parameters in the STP process including polishing speed, diamond abrasive size and diamond abrasive concentration were analyzed. To investigate the potential mechanical effect of the nanometre abrasive, nano-SiO 2 abrasive particles were added in the slurry, and the concentration of SiO 2 abrasive was also taken as a factor. Taguchi method was utilized to evaluate the influence of the four factors and optimize the polishing conditions. The surface roughness (Ra/Rz) was used as the evaluation index, and the optimized polishing conditions were verified through experiments. Diamond abrasive size has the most significant effect on Ra/Rz, followed by diamond abrasive concentration and then SiO 2 concentration, as the polishing speed has been selected and limited in a small variation rang according to the previous study. Based on the S/N average response analysis, the surface quality is the best under the conditions with 8000# diamond abrasive, 5 wt% diamond abrasive concentration, 90 rpm polishing speed and 10 wt% SiO 2 concentration. After 4 min polishing, the surface roughness Ra/Rz is reduced rapidly from 200.5/1374.6 to 4.2/22.1 nm without embedded abrasive particles on the surface of the black LT substrate. It also shows that the mechanical effect plays a dominant role in the material removal. A certain amount (10 wt% in this study) of nano-SiO 2 can reduce friction between solid colloidal and workpiece, and helps to improve surface quality.
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
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.
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.
Zhang, X.,Lian, Q.,Pan, Q.,Yuan, G.,Seo, H.J. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.607 No.-
Ce<SUP>3+</SUP> and Tb<SUP>3+</SUP> ions are important activators for various phosphors, but no detailed study has been performed on SrLiB<SUB>9</SUB>O<SUB>15</SUB> crystal. Ce<SUP>3+</SUP>- and Ce<SUP>3+</SUP>/Tb<SUP>3+</SUP>-doped SrLiB<SUB>9</SUB>O<SUB>15</SUB> phosphors were synthesized by using a standard high temperature solid-state technique. The phase purity and optical properties of the prepared samples are investigated by XRD, excitation and emission spectra. The unusual luminescence properties of Ce<SUP>3+</SUP> activator, the Ce<SUP>3+</SUP> site occupying and Ce<SUP>3+</SUP>→Tb<SUP>3+</SUP> energy transfer behavior are discussed.
Liu L.N.,Liang Q.C.,Yang H.,Zhang X.J.,Yuan S.,Mao Y.Z.,Zhang W.,Zhu G.H.,Wang L.,Qin C.M.,Zhao Y.P.,Cheng Y.,Zhang K. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10
To operate the ion cyclotron resonance heating (ICRH) antennas in a better heating state and produce relatively low impurities, it is necessary to control the antenna spectrum by changing the antenna phasing. As the electrical length of the antenna feeding transmission lines is changing as a matter of the standing wave pattern at the ceramic supports, 90 elbows, T-connectors and antenna loops, we chose to measure the current at the grounding points of the antenna loops by antenna strap probe. The voltage drops along a small, several millimeter-long paths at the end of the antenna loops give a signal that is proportional to the current in the antenna loop. Through the simulation of the antenna strap probe and the actual measurement of the antenna phasing under vacuum conditions, the reliability of the antenna strap probe based diagnostic system have been successfully proved. Moreover, this system was successfully applied to the ICRH daily experiments in the spring of 2021. In the near future, the active realtime feedback control of the antenna phasing system will be developed based on this diagnostic system in the EAST tokamak.
Synthesis and pressure effects on the La doped CaFe<sub>2</sub>As<sub>2</sub>
Shin, Soohyeon,Shang, T.,Yuan, H.Q.,Park, Tuson 한국초전도저온공학회 2014 한국초전도저온공학회논문지 Vol.16 No.3
We have synthesized La doped $CaFe_2As_2$ single crystals with Sn flux in an evacuated quartz ampule. Doping and pressure effects on the magnetic and superconducting properties of the under-doped $Ca_{1-x}La_xFe_2As_2$ (x=0.08, 0.1) were studied by measuring electrical resistivity under quasi-hydrostatic pressure up to 21 kbar. Magnetic transition temperatures for all studied concentrations were sharply suppressed with slight amplitude of pressure, less than 3 kbar, while superconducting transition temperatures were robust against pressure. In this communication, we report temperature-pressure phase diagram for the La-doped $CaFe_2As_2$ single crystals.