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108. High resolution OSL dating of aeolian activity at Qinghai Lake, Northeast Tibetan Plateau

Author

Zhao Yajuan, E Chongyi, Shi YunKun, Chen Zong-yan, Zhang Jing, Sun Yongjuan, Li Ping, and Sun ManPing

Subjects
geography, Plateau, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 04 agricultural and veterinary sciences, 01 natural sciences, Paleosol, Sedimentary depositional environment, Pedogenesis, 040103 agronomy & agriculture, Erosion, 0401 agriculture, forestry, and fisheries, Aeolian processes, Physical geography, Glacial period, Holocene, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

Qinghai Lake is the largest lake on the Tibetan Plateau (TP), located between the extremely arid Qaidam Basin to the west and the severely desertified Gonghe Basin to the south. Extensive aeolian sediment at Qinghai Lake is ideal material to reconstruct regional aeolian activity, and to better understand the relationship between desertification and climatic change in the lake basin. Aeolian sand accumulation is usually accompanied by erosion, hence, depositional hiatuses and disconformities must be identified for reliable reconstruction of regional aeolian activity. To date, the low density of age sampling around Qinghai Lake has hindered identification of hiatuses. In this study we report the first high density OSL dating; 41 OSL ages were obtained from two aeolian sand sections, Dongwei (DW) and Niaodao (ND). Sand accumulation trends recorded in the high-density OSL sampling sections were consistent with previously published probability density function (PDF) ages for the northeast TP. The middle Holocene (~7 to ~4 ka) was characterized by very low accumulation rates, with rapid sedimentation in the Late Glacial to Early Holocene (~14 to ~7 ka) and the Late Holocene (after ~4 ka). A ~3 ka hiatus in accumulation between ~7 to ~4 ka was identified in the DW section, but the ND section showed successive accumulation since the Late Glacial (~14 ka), on sub-orbital and millennial scales. Our environmental reconstructions are consistent with previously published aeolian data and paleoshorelines records. The combined evidence shows: strong aeolian activity since ~14 ka to ~9 ka; initiation of pedogenesis at ~9 to 7 ka; intensified soil development between ~7 ka and ~4 ka (with the most intense pedogenesis and least aeolian activity between ~6 to ~4 ka); relatively weak paleosol formation from ~4 to ~2 ka; and renewed aeolian activity after ~2 ka.

Published
2019

118. Metastable Tetragonal BiFeO3Stabilized on Anisotropic a-Plane ZnO

Author

Zhao, Yajuan, Yin, Zhigang, Li, Xingxing, Zheng, Maoyuan, Cheng, Yong, You, Jingbi, Wu, Jinliang, and Zhang, Xingwang

Abstract

The stabilization of the metastable tetragonal phase of BiFeO3on the highly anisotropic ZnO(11-20) surface is reported. X-ray reciprocal space maps reveal that the BiFeO3layer possesses true tetragonal symmetry rather than the monoclinic MCor MAstructures. Heteroepitaxy generates strongly anisotropic misfit strains of 2.4 and −5.3% along two orthogonal ⟨110⟩ directions of tetragonal BiFeO3. Our analysis shows that such anisotropic strains are very powerful in tailoring the energy balance of competing phases, favoring the formation of tetragonal BiFeO3. Tetragonal BiFeO3can be stabilized on the ZnO template up to a critical thickness of 110 nm, much larger than that of its monoclinic counterparts. The integration of such thick tetragonal BiFeO3films with ZnO has important implications for future applications, as exemplified by the demonstration of a prototype metal/ferroelectric/semiconductor capacitor and the preparation of flexible tetragonal BiFeO3nanomembranes. Additionally, the heteroepitaxial growth was also transposed to the integration of other perovskite oxides with ZnO. Our findings not only shed new light into the strain phase diagram of BiFeO3but also open up a possible avenue toward oxide electronics.

Published
2021
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119. Controlled Growth of Edge‐Enriched ReS2 Nanoflowers on Carbon Cloth Using Chemical Vapor Deposition for Hydrogen Evolution.

Author

Zhao, Yajuan, Li, Jianguo, Huang, Jianfeng, Feng, Liangliang, Cao, Liyun, Feng, Yongqiang, Zhang, Zhaohui, Xie, Yong, and Wang, Haolin

Subjects
CHEMICAL vapor deposition, HYDROGEN evolution reactions, GAS flow, HYDROGEN, VAPOR pressure
Abstract

Rhenium disulfide (ReS2) has attracted tremendous interests as a promising electrocatalyst for hydrogen evolution reaction (HER) due to its unique distorted 1T structure. However, the controllable synthesis of ReS2 with desired nanostructures is still a challenge for improving its catalytic performance. Here, ReS2 nanoflowers are constructed on conductive carbon cloth by means of ambient pressure chemical vapor deposition. Characterization results confirm that the nanoflower structure with enormous edges is attributed to its propensity of out‐of‐plane growth. To investigate the structure variation of the nanoflowers, systematic growth experiments are carried out. By tuning the growth temperature, gas flow rate, and precursor mass, the edge‐exposed architecture is achieved. The dependence of catalytic performance on microstructures is further established, revealing that the ReS2 nanoflowers with maximized edge sites exhibit optimal catalytic performance. These findings provide a guideline for optimizing the HER performance of ReS2 and broaden the vision of improving novel HER catalysts. [ABSTRACT FROM AUTHOR]

Published
2020
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120. Attractors and their upper semicontinuity for the quasi-linear membrane equation withstructural damping

Author

Yang Zhijian, Ding Pengyan, and Zhao Yajuan

Subjects
Polynomial (hyperelastic model), Physics, Growth restriction, Semigroup, General Mathematics, Attractor, Quasi linear, Natural energy, Space (mathematics), Critical exponent, Mathematical physics
Abstract

The paper investigates the well-posedness and longtime dynamicsof the quasi-linear membrane equation with structural damping:$u_{tt}+\\Delta^{2}u+(-\\Delta)^{\\alpha}u_{t}+\\Delta\\phi(\\Delta~u)+f(u)=g$, with $\\alpha\\in(1,2)$. We are concerned with the influence of the dissipative index $\\alpha$ to the well-posedness and longtime dynamics of the equation. We show that there exists a critical exponent $p_\\alpha=\\frac{N+4(\\alpha-1)}{(N-4(\\alpha-1))^+}$ of the nonlinearity $\\phi(s)$, which depends on the dissipative index $\\alpha$, such that when $1\\leq~p

Published
2019

121. Synthesis and High Visible Light Photocatalytic Activity of Ternary Brookite-g-C3N4-BiOBr Composite.

Author

Liu, Ning, Xie, Huidong, Li, Jie, Zhao, Yajuan, and Wang, Na

Subjects
VISIBLE spectra, RHODAMINE B, TITANIUM dioxide, SILVER phosphates
Abstract

Brookite TiO2 was synthesized by a hydrothermal method, g-C3N4 was prepared by a pyrolytic method, brookite/g-C3N4 composites were prepared by a calcining method, and brookite/g-C3N4/BiOBr ternary composites were prepared by loading BiOBr on the surface of brookite/g-C3N4. XRD and XPS analysis of the composites confirmed the formation of brookite TiO2/g-C3N4/BiOBr. SEM and TEM results confirmed the as-prepared composites were nanosized. The optimum loading amount of BiOBr was 30%. The photocatalytic results showed that the brookite/g-C3N4/30%BiOBr composites degraded rhodamine B completely under visible light irradiation. The degradation ratio of brookite/g-C3N4/30%BiOBr toward rhodamine B was nearly 100% for 2 h, which was much higher than that of brookite TiO2 and brookite/g-C3N4 catalysts. The reason for the improvement of photocatalytic activity might be because the composites promoted the formation of superoxide radicals and the separation efficiency of photogenerated electron-hole pairs. The photocurrent density of the brookite/g-C3N4/30%BiOBr was about 10 times higher than that of pure brookite. In addition, the brookite/g-C3N4/BiOBr showed a good repeatablity of photocatalysis. Ternary brookite/g-C3N4/BiOBr photocatalytic composites were prepared by several steps. TEM showed brookite spindel, BiOBr nanoplates and amorphous C3N4 interwined together. The composites have a good photocatalytic activity for the degradation of RhB solution as well as a good recyclability. The degradation ratio is still close to 100% after four times of recycle. [ABSTRACT FROM AUTHOR]

Published
2020
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122. Discovery of 3-Cyano-N-(3-(1-isobutyrylpiperidin-4-yl)-1-methyl-4-(trifluoromethyl)-1H-pyrrolo[2,3-b]pyridin-5-yl)benzamide: A Potent, Selective, and Orally Bioavailable Retinoic Acid Receptor-Related Orphan Receptor C2 Inverse Agonist

Author

Schnute, Mark E., primary, Wennerstål, Mattias, additional, Alley, Jennifer, additional, Bengtsson, Martin, additional, Blinn, James R., additional, Bolten, Charles W., additional, Braden, Timothy, additional, Bonn, Tomas, additional, Carlsson, Bo, additional, Caspers, Nicole, additional, Chen, Ming, additional, Choi, Chulho, additional, Collis, Leon P., additional, Crouse, Kimberly, additional, Färnegårdh, Mathias, additional, Fennell, Kimberly F., additional, Fish, Susan, additional, Flick, Andrew C., additional, Goos-Nilsson, Annika, additional, Gullberg, Hjalmar, additional, Harris, Peter K., additional, Heasley, Steven E., additional, Hegen, Martin, additional, Hromockyj, Alexander E., additional, Hu, Xiao, additional, Husman, Bolette, additional, Janosik, Tomasz, additional, Jones, Peter, additional, Kaila, Neelu, additional, Kallin, Elisabet, additional, Kauppi, Björn, additional, Kiefer, James R., additional, Knafels, John, additional, Koehler, Konrad, additional, Kruger, Lars, additional, Kurumbail, Ravi G., additional, Kyne, Robert E., additional, Li, Wei, additional, Löfstedt, Joakim, additional, Long, Scott A., additional, Menard, Carol A., additional, Mente, Scot, additional, Messing, Dean, additional, Meyers, Marvin J., additional, Napierata, Lee, additional, Nöteberg, Daniel, additional, Nuhant, Philippe, additional, Pelc, Matthew J., additional, Prinsen, Michael J., additional, Rhönnstad, Patrik, additional, Backström-Rydin, Eva, additional, Sandberg, Johnny, additional, Sandström, Maria, additional, Shah, Falgun, additional, Sjöberg, Maria, additional, Sundell, Aron, additional, Taylor, Alexandria P., additional, Thorarensen, Atli, additional, Trujillo, John I., additional, Trzupek, John D., additional, Unwalla, Ray, additional, Vajdos, Felix F., additional, Weinberg, Robin A., additional, Wood, David C., additional, Xing, Li, additional, Zamaratski, Edouard, additional, Zapf, Christoph W., additional, Zhao, Yajuan, additional, Wilhelmsson, Anna, additional, and Berstein, Gabriel, additional

Published
2018
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131. Discovery of a JAK3-Selective Inhibitor: Functional Differentiation of JAK3-Selective Inhibition over pan-JAK or JAK1-Selective Inhibition

Author

Telliez, Jean-Baptiste, primary, Dowty, Martin E., additional, Wang, Lu, additional, Jussif, Jason, additional, Lin, Tsung, additional, Li, Li, additional, Moy, Erick, additional, Balbo, Paul, additional, Li, Wei, additional, Zhao, Yajuan, additional, Crouse, Kimberly, additional, Dickinson, Caitlyn, additional, Symanowicz, Peter, additional, Hegen, Martin, additional, Banker, Mary Ellen, additional, Vincent, Fabien, additional, Unwalla, Ray, additional, Liang, Sidney, additional, Gilbert, Adam M., additional, Brown, Matthew F., additional, Hayward, Matthew, additional, Montgomery, Justin, additional, Yang, Xin, additional, Bauman, Jonathan, additional, Trujillo, John I., additional, Casimiro-Garcia, Agustin, additional, Vajdos, Felix F., additional, Leung, Louis, additional, Geoghegan, Kieran F., additional, Quazi, Amira, additional, Xuan, Dejun, additional, Jones, Lyn, additional, Hett, Erik, additional, Wright, Katherine, additional, Clark, James D., additional, and Thorarensen, Atli, additional

Published
2016
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133. Effect of Gd3+, Bi3+, or Sm3+ on luminescent properties of La2−xMgTiO6:xEu3+ phosphors.

Author

Xie, Huidong, Su, Binbin, Tan, Yurong, Zhao, Yajuan, and Chai, Shouning

Abstract

Single phase of Bi3+, Gd3+, Sm3+ and Eu3+ co‐doped La2MgTiO6 red phosphors were synthesized by high temperature solid‐state method. The phase composition, morphology and fluorescent properties of the phosphors were analyzed by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrometer. The La2‐xMgTiO6:xEu3+ phosphors can be excited by UV (396 nm) and blue (465 nm) light‐emitting diode (LED) chips and show a strong red emitting with dominated wavelength at 615 nm. The optimum doping concentration of Eu3+ ion for La2MgTiO6 is x = 0.5. The luminescent intensities of 5D0 → 7F2 transition of Eu3+ in La1.5‐yMgTiO6:0.5Eu3+, yBi3+/Gd3+/Sm3+ were 1.31 times, 1.32 times and 1.88 times that of La1.5MgTiO6:0.5Eu3+ at y = 0.08, 0.06, 0.06 for Bi3+, Gd3+, or Sm3+ sensitizer, respectively. The chromaticity coordinates of La1.44MgTiO6:0.5Eu3+, 0.06Sm3+, (0.6342, 0.3513) were very close to those of the National Television Standard Committee (NTSC) standard red light coordinates. [ABSTRACT FROM AUTHOR]

Published
2018
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134. Effect of oxidation treatment on the carbon nanotube grafting carbon fiber composites and their electromagnetic properties.

Author

LI Baoyi, ZHANG Huanhuan, WANG Donghong, ZHANG Zekui, and ZHAO Yajuan

Abstract

In order to solve the problems such as singleness of the absorption mechanism, difficulty of dispersion and inability of broadband absorption, carbon nanotubes were successfully prepared on the surface of acid oxidized carbon fiber by chemical grafting method. The effect of oxidation treatment on the carbon nanotubes modified carbon fiber and their electromagnetic properties were investigated. The results showed that the graft amount and graft efficiency of CNT were improved by oxidation treatment, resulting in the enhancement of the dielectric constant and the electromagnetic wave loss performance. At the condition of the nitric acid concentration of 65% and the reaction time of 8h, the grafted CNTs on the surface of CF reached 15.3% without agglomeration, which showed a good electromagnetic wave absorption property. [ABSTRACT FROM AUTHOR]

Published
2018
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135. Preparation and Properties of Eu2+, Dy3+ Co-Doped Alkaline Earth Silicate Fluorescent Powders

Author

谢会东 Xie Huidong, 陈利君 Chen Lijun, 李 兆 Li Zhao, 张 勇 Zhang Yong, 王晓端 Wang Xiaoduan, 赵亚娟 Zhao Yajuan, and 陈双莉 Chen Shuangli

Subjects
chemistry.chemical_compound, Alkaline earth metal, Materials science, chemistry, Electrical and Electronic Engineering, Fluorescence, Atomic and Molecular Physics, and Optics, Silicate, Co doped, Nuclear chemistry
Published
2017

146. Pointwise convergence problem of the Korteweg–de Vries–Benjamin–Ono equation.

Author

Zhao, Yajuan, Yan, Xiangqian, Yan, Wei, and Li, Yongsheng

Subjects
*FRACTAL dimensions, *EQUATIONS
Abstract

In this paper we investigate the pointwise convergence problem for the Korteweg–de Vries–Benjamin–Ono equation u t + γ H (∂ x 2 u) − β ∂ x 3 u = 0 , (x , t) ∈ R × R , u (x , 0) = f (x) ∈ H s (R) , where γ β > 0. We prove that the solution u (x , t) = U t f (x) converges pointwisely to the initial data f (x) for a.e. x ∈ R when f ∈ H s (R) with s ≥ 1 4 , and that the Hausdorff dimension of the divergence set of points of the solution is α U (s) = 1 − 2 s when 1 4 ≤ s ≤ 1 2 . We also obtain the stochastic continuity for the initial data with much less regularity, i.e. for a large class of the initial data in L 2 (R) , via the randomization technique. [ABSTRACT FROM AUTHOR]

Published
2022
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148. Hydrothermal Synthesis and Photocatalytic Activities of PbBi 2 Nb 2 O 9 Nanoplates.

Author

Xie, Huidong, Chang, Xin, Yang, Wei, Jiang, Yuanru, and Zhao, Yajuan

Subjects
HYDROTHERMAL synthesis, PHOTOCATALYSTS, NIOBATES, LEAD compounds, BISMUTH compounds, X-ray diffraction, NANOSTRUCTURED materials synthesis
Abstract

Single phase of PbBi2Nb2O9nanoplates was successfully synthesized by a hydrothermal method for the first time, using Pb(NO3)2, Bi(NO3)3·5H2O, and Nb2O5as the starting materials and NaOH as the mineralizer. The influences of the reaction conditions on the phases and morphologies of the products were investigated by X-ray diffraction and scanning electron microscopy. Diffuse reflectance spectra showed the band gap of as-synthesized PbBi2Nb2O9was 2.79 eV. Meanwhile, the photocatalytic activity for the decolorization of methylene blue under ultraviolet light irradiation of PbBi2Nb2O9plates was evaluated. [ABSTRACT FROM AUTHOR]

Published
2016
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149. Formation and local conduction of nanopits in BiFeO3 epitaxial films.

Author

Zhao, Yajuan, Yin, Zhigang, Zhang, Xingwang, Fu, Zhen, and Wu, Jinliang

Abstract

The creation and manipulation of one-dimensional conducting channels, V-shaped nanopits, in otherwise insulating BiFeO3 epilayers are reported. The formation and thickness-dependent evolution of nanopits have a close correlation with the relaxation of shear strain that stems from the crystal symmetry mismatch between BiFeO3 and the substrate. The local conduction at the nanopits exhibits a rectification behavior, and is governed by interface-regulated Poole–Frenkel emission. The accumulation of oxygen vacancies near the nanopits not only modifies the interface barrier height, but also delivers donor states in the vicinity of the conduction band edge, and therefore leads to locally enhanced nanopit conductance. Our findings provide a new insight into the interplay between defects and epitaxial strain, and open up a possible avenue for oxide nanoelectronics. [ABSTRACT FROM AUTHOR]

Published
2015
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