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Sub-lattice polarization states in anti-ferroelectrics and their relaxation process
M.M. Vopson,X. Tan,E. Namvar,M. Belusky,S.P. Thompson,V. Kuncser,F. Plazaola,I. Unzueta,C.C. Tang 한국물리학회 2019 Current Applied Physics Vol.19 No.4
We report studies of quasi-remanent polarization states in Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3 (PNZST) anti-ferroelectric ceramics and investigation of their relaxation effects using unique in-situ electrically activated time-resolved Synchrotron X-ray powder diffraction (SXPD) and 119Sn Mössbauer Spectroscopy (MS). The SXPD patterns are consistent with a phase transition from quasi-tetragonal perovskite in 0 V relaxed anti-ferroelectric state to rhombohedral distortion in ferroelectric state under saturating applied voltages of±2 kV. The observed quasi-remanent polarization relaxation processes are due to the fact that tetragonal to rhombohedral distortion does not occur at the applied voltage required to access the quasi-remanent polarization states, and the tetragonal symmetry restored after the removal of the applied electric field is preserved. Since these quasi-remanent polarization states were seen as possibly suitable for memory applications, the implications of this study are that anti-ferroelectrics are more feasible for multi-state dynamic random access memories (DRAM), while their application to non-volatile memories requires development of more sophisticated “read-out” protocols, possibly involving dc electrical biasing.
Cloning and characterization of a novel GIGANTEA gene in sweet potato
Tang, W.,Yan, H.,Su, Z.x.,Park, S.C.,Liu, Y.j.,Zhang, Y.g.,Wang, X.,Kou, M.,Ma, D.f.,Kwak, S.S.,Li, Q. Gauthier-Villars ; Elsevier Science Ltd 2017 Vol. No.
<P>The transition from vegetative to reproductive growth, a key event in the lifecycle of a plant, is affected by environmental stresses. The flowering-time regulator GIGANTEA (GI) may be contributing to susceptibility of the regulation of photoperiodic flowering, circadian rhythm control, and abiotic stress resistance in Arabidopsis. However, the role of GI in sweet potato remains unknown. Here, we isolated and characterized a GI gene (IbGI) from sweet potato (Ipomoea batatas [LI Lam). The IbGI cDNA sequence was isolated based on information from a sweet potato transcriptome database. IbGI mRNA transcript levels showed robust circadian rhythm control during the light-dark transition, and the expression of IbGI was stronger in leaves and roots than in stems. IbGI protein is predominantly localized to the nucleus. IbGI expression was upregulated by high temperature, drought, and salt stress but downregulated by cold stress. Overexpressing IbGI in the Arabidopsis gi-2 mutant background rescued its late flowering phenotype and reduced its salt tolerance. Taken together, these results indicate that IbGI shares functions in regulating flowering, the circadian rhythm, and tolerance to some stresses with other GI orthologs. (C) 2017 Elsevier Masson SAS. All rights reserved.</P>
Tang, S.X.,Li, F.W.,Gan, J.,Wang, M.,Zhou, C.S.,Sun, Z.H.,Han, X.F.,Tan, Z.L. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.6
The effects of seedtime and maturity stage on nutritive value of five maize stover varieties, including conventional maize (Kexiangyu 11, CM), fodder maize (Huqing 1, FM), high oil maize (Gaoyou 115, HOM), sweet maize (Kexiangtianyu 1, SM) and waxy maize (Kexiangluoyu 1, WM), were examined based on chemical composition, in vitro gas production and in situ incubation techniques. Maize stover was sampled at d 17 and d 30 after tasseling, and designated as maturity stage 1 and stage 2, respectively. The average dry matter (DM) organic matter (OM), crude protein (CP) and fiber contents were the greatest for HOM, SM and FM, respectively. CM had the highest in vitro organic matter disappearance (IVOMD) and volatile fatty acid (VFA) concentration. The highest ammonia nitrogen ($NH_3$-N) concentration in the incubation solution, and effective degradability of DM ($ED_{DM}$) and neutral detergent fiber ($ED_{NDF}$) were observed in SM. Advanced maturity stage increased (p<0.05) DM content, $ED_{DM}$ and $ED_{NDF}$, but decreased (p<0.05) OM and CP contents, and decreased (p<0.05) b and a+b values, IVOMD and molar proportion of valerate in the incubation solution for maize stover. Maize sown in summer had greater (p<0.05) OM content, but lower DM, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) content compared with maize sown in spring. Maize sown in summer had greater (p<0.001) IVOMD, $NH_3$-N concentration in the incubation solution and $ED_{NDF}$, but lower (p<0.01) ratio of acetate to propionate compared to maize sown in spring. The interaction effect of variety${\times}$seedtime was observed running through almost all chemical composition, in vitro gas production parameters and in situ DM and NDF degradability. The overall results suggested that SM had the highest nutrient quality, and also indicated the possibility of selecting maize variety and seedtime for the utilization of maize stover in ruminants.
Tang, W.K.,Wong, K.B.,Lam, Y.M.,Cha, S.S.,Cheng, C.H.K.,Fong, W.P. North-Holland Pub ; Elsevier Science Ltd 2008 FEBS letters Vol.582 No.20
The crystal structure of seabream antiquitin in complex with the cofactor NAD<SUP>+</SUP> was solved at 2.8A resolution. The mouth of the substrate-binding pocket is guarded by two conserved residues, Glu120 and Arg300. To test the role of these two residues, we have prepared the two mutants E120A and R300A. Our model and kinetics data suggest that antiquitin's specificity towards the substrate α-aminoadipic semialdehyde is contributed mainly by Glu120 which interacts with the α-amino group of the substrate. On the other hand, Arg300 does not have any specific interaction with the α-carboxylate group of the substrate, but is important in maintaining the active site conformation.
Inductances of a Superconducting Magnet for Cyclotron K120
Tang, H.M.,Kim, D.L.,Choi, Y.S.,Lee, B.S.,Yang, H.S.,Kim, Y.S. The Korean Society of Superconductivity and Cryoge 2008 한국초전도저온공학회논문지 Vol.10 No.4
The design of a superconducting magnet system producing very high magnetic field is underway at Korea Basic Science Institute (KBSI) to accelerate three kinds of carbon irons (C+2, C+4, C+6) to 120 MeV. A quarter-scaled prototype will be manufactured in order to confirm the feasibility of our design. Magnet Inductances in the system have a great influence on the current ramping rates and contribute to the stored energy, which are usually considered to be unfavorable in magnet operation. The modeling and simulation scheme of a prototype superconducting magnet for the cyclotron K120 is described in this paper. The inductances are calculated by a numerical method with and without iron yokes, respectively. These calculation results will be used as engineering design details such as a current ramping rate and a quench protection design.
Enhanced Mechanical Properties of Orthorhombic Ti₂AlNb-Based Intermetallic Alloy
Hagiwara, M.,Emura, S.,Araoka, A.,Kong, B.O.,Tang, F. 대한금속재료학회 2003 METALS AND MATERIALS International Vol.9 No.3
Attempts were made to improve the mechanical properties of an orthorhombic Ti₂AlNb-based Ti-22Al-27Nb intermetallic alloy through microstructural and compositional modifications, and the dispersion of fine TiB particulates. A Ti-22Al-27Nb alloy with a prior B2 grain size ranging from 8 mm to 49 ㎛ was successfully obtained using spherical α₂particles as obstacles to grain growth. The finest grained material showed an excellent combination of room temperature tensile strength (around 1,000 MPa) and tensile ductility (more than 15 %). Transition metal elements such as Mo, V and W for a portion of the Nb in the Ti-22Al-27Nb were substituted. The guideline for this compositional modification required that the beta phase stability in the modified alloy be equal to that of the Ti-22Al-27Nb. It was found that the substitution of 2 % W for 7 % Nb was quite effective in increasing tensile strength at temperatures above 923 K and reducing the steady state creep rate and primary creep strain. The Ti-22Al-27Nb alloy-based particulate composites reinforced with 6.5 % TiB were successfully produced with the gas atomization P/M method. The dispersion of extremely small TiB was very uniform. Most of the mechanical properties of the composites, including the yield stress, tensile strength, Young's modulus, resistance to creep, and high cycle fatigue strength were greatly superior to those of the matrix alloy.