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253. Mechanical properties and densification mechanism of powder-in-tube Ba x K1−x Fe2As2 superconductors

Author

Han, Meng, primary, Yao, Chao, additional, Zhang, Xianping, additional, Wang, Dongliang, additional, Dong, Chiheng, additional, Liu, Cong, additional, Huang, He, additional, Yang, Peng, additional, Guo, Wenwen, additional, Tu, Chang, additional, Liu, Shifa, additional, Liu, Xinyuan, additional, Zhang, Qianjun, additional, Zhang, Zhihao, additional, Xie, Jianxin, additional, and Ma, Yanwei, additional

Published
2022
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255. Flux Pinning Properties of 7-Filament Cu/Ag-Sheathed Ba1-xKxFe2As2 Tapes at 4.2 K

Author

Luo, Junyi, Okada, Tatsunori, Awaji, Satoshi, Liu, Cong, and Ma, Yanwei

Abstract

We investigated the magnetic field and angular dependence of the critical current Ic(B, θ) of 7-filament Cu/Ag-sheathed Ba1-xKxFe2As2 (Ba122) tapes at 4.2 K. Below approximately 8 T, Ic(B, θ) exhibited hysteresis behaviors depending on increasing or decreasing B, Icup(B) or Icdown(B), as well as changes in θ in a positive or negative rotation direction, Icpos(θ) or Icneg(θ). Icup(B) exhibited a non-monotonic dependence on B, which was explained by the flux pinning of Abrikosov vortices in grains and Abrikosov-Josephson vortices at grain boundaries. Ic(B, θ) exhibited an anomalous anisotropy Ic(B, 90°)/Ic(B, 0°) < 1 opposed to the effective-mass model. We calculated Jc(B, θ) numerically by treating the angular dependence of the elementary pinning force owing to a spherical pin with a radius of approximately 8 nm, and successfully reproduced the measured Ic(B > 8 T, θ) and Icavg(B, θ) = [Icpos(B, θ) + Icneg(B, θ)]/2 at B < 8 T. This suggests that spherical pins play an important role in vortex pinning, and controlling them may improve the Ic(T, B, θ) characteristics in 7-filament Cu/Ag-sheathed Ba122 tapes.

Published
2023
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262. Appropriate Bandwidth Achieved High Yield Via Shrinking Maize Intraspecific Competition in an Additive Maize-Soybean Strip Intercropping

Author

Liang, Bing, primary, Ma, Yanwei, additional, Shi, Kai, additional, Chen, Guopeng, additional, Chen, Hong, additional, Hu, Yun, additional, Chen, Ping, additional, Pu, Tian, additional, Wu, Yushan, additional, Sun, Xin, additional, Yong, Taiwen, additional, Liu, Weiguo, additional, Liu, Jiang, additional, Du, Junbo, additional, Yang, Feng, additional, Wang, Xiaochun, additional, and Yang, Wenyu, additional

Published
2022
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263. Effect of bending before annealing on current-carrying properties of iron-based superconducting tapes

Author

Li, Chunyan, primary, Kang, Rui, additional, Zhu, Yanchang, additional, Zhang, Zhen, additional, Wang, Yingzhe, additional, Wang, Chengtao, additional, Zhou, Jin, additional, Yao, Huanli, additional, Zhang, Xianping, additional, Wang, Dongliang, additional, Liu, Fang, additional, Liu, Cong, additional, Ma, Yanwei, additional, and Xu, Qingjin, additional

Published
2022
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267. Progress of ultra-high-field superconducting magnets in China

Author

Wang, Qiuliang, primary, Liu, Jianhua, additional, Zheng, Jinxing, additional, Qin, Jinggang, additional, Ma, Yanwei, additional, Xu, Qingjin, additional, Wang, Dongliang, additional, Chen, Wenge, additional, Qu, Timing, additional, Zhang, Xingyi, additional, Jiang, Donghui, additional, Wang, Yaohui, additional, Zhou, Benzhe, additional, Qin, Lang, additional, Jin, Huan, additional, Liu, Huajun, additional, Zhai, Yujia, additional, and Liu, Feng, additional

Published
2021
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269. Interface effects on the current transport properties of multi-layered (Ba, K)Fe2As2 superconducting wires.

Author

Yao, Chao, Guo, Wenwen, Zhu, Yanchang, Liu, Xinyuan, Han, Meng, Liu, Fang, Liu, Huajun, Qin, Jinggang, Zheng, Jinxing, and Ma, Yanwei

Abstract

Iron-based superconductors (IBSs) are very promising candidates for high-field applications owing to their ultrahigh upper critical field and very small electromagnetic anisotropy. For practical applications, it is essential to develop multifilamentary superconducting wires with high transport critical current density (Jc). Here, we report the development of multi-layered Cu/Ag composite sheathed (Ba, K)Fe2As2 (Ba-122) superconducting wires using a tape-in-tube method. The wires consist of a tape-shaped Ba-122 filament with an improved grain alignment, showing an enhanced transport Jc of 2.8 × 104 A cm−2 at 4.2 K and 10 T, about two times higher than that of the Ba-122 wires prepared using the conventional powder-in-tube method. Furthermore, the evolution of the superconducting properties of the 3-, 7- and 11-filament tape-in-tube wires is systematically investigated in connection with the grain texture, mass redistribution and interface effects. Through 3D X-ray tomographic reconstruction and electron probe micro-analysis, we found that the filament uniformity and chemical composition homogeneity of the Ba-122 wires can be greatly affected by the interface between the Ba-122 filament and the Ag matrix. Our work suggested that in addition to the grain connectivity and grain texture that have been extensively studied for the single-core IBS wires, the Ba-122/Ag interface also plays an important role in the phase homogeneity and Jc performance of the multifilamentary wires. [ABSTRACT FROM AUTHOR]

Published
2023
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270. Unveil Overcharge Performances of Activated Carbon Cathode in Various Li-Ion Electrolytes.

Author

Sun, Xianzhong, An, Yabin, Zhang, Xiong, Wang, Kai, Yuan, Changzhou, Zhang, Xiaohu, Li, Chen, Xu, Yanan, and Ma, Yanwei

Subjects
ELECTROLYTES, CATHODES, DIELECTRIC films, PROPYLENE carbonate, ENERGY consumption, ACTIVATED carbon, ANODES, LITHIUM
Abstract

Typically, the practical lithium-ion capacitor (LIC) is composed of a capacitive cathode (activated carbon, AC) and a battery-type anode (graphite, soft carbon, hard carbon). There is a risk of the LIC cell overcharging to an unsafe voltage under electrical abuse conditions. Since the anode potential is usually quite low during the charging process and can be controlled by adjusting the amount of anode materials, the overcharge performances of LIC full-cell mainly depend on the AC cathode. Thus, it is necessary to independently investigate the overcharge behaviors of the AC cathode in nonaqueous Li-ion electrolytes without the interference of the anode electrode. In this work, the stable upper potential limits of the AC electrode in three types of lithium-ion electrolytes were determined to be 4.0−4.1 V via the energy efficiency method. Then, the AC//Li half-cells were charged to 5.0 V and 10.0 V, respectively, to investigate the overcharge behaviors. For the half-cells with propylene carbonate (PC)-based electrolytes, the voltage increased sharply to 10.0 V with a vertical straight line at the end of the overcharging process, indicating that the deposits of electrolyte decomposition had separated the AC electrode surface from the electrolytes, forming a self-protective passivation film with a dielectric capacitor behavior. The dense and compact passivation film is significant in separating the AC electrode surface from the electrolytes and preventing LIC cells from volume expansion and explosion risks under electrical abuse and overcharging conditions. [ABSTRACT FROM AUTHOR]

Published
2023
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274. Magnetic properties of (Co, Ni, Mn)3O4 spinels

Author

Durán, P., Peña, O., Bahout, M., Ma, Yanwei, and Moure, C.

Subjects
Magnetic oxides, spinels, magnetic exchange, ferrimagnetic properties, Óxidos magnéticos, espinelas, interacciones de intercambio, ferromagnetismo, Clay industries. Ceramics. Glass, TP785-869
Abstract

Magnetic properties of new materials, based on the general formula CoxNiyMnzO4 (x+y+z= 3), have been investigated as a function of magnetic field and temperature. The behavior observed in the paramagnetic regime (220 K ≤ T ≤ 400 K) shows a direct correlation with the nominal cation concentration. The paramagnetic-ferrimagnetic transition which takes place at T = Tc depends on the overall composition, going from Tc = 120 K (for Co0.2NiMn1.8O4) up to Tc = 210 K (for Co1.2Ni0.3Mn1.5O4). A second transition is observed at lower temperatures, corresponding to a second ordered magnetic sublattice. This second transition takes place at about 60 K (for Co0.6NiMn1.4O4), increasing with the cobalt content up to about 160 K. Under an external magnetic field, both transitions merge into a single one, with a characteristic temperature Tmax, which rapidly decreases with increasing field. Magnetization loops M(H) obtained at 5 K show a typical behavior of soft magnetic materials, with low coercive fields. Low conductivity values were observed at room‑temperature, increasing by a factor of 200-1000 at high temperatures (400 C), which make these compounds to be very interesting materials for potential applications as NTCR thermistors.Se han investigado las propiedades magnéticas de materiales de fórmula CoxNiyMnzO4 (x+y+z+ = 3), en función del campo magnético aplicado y de la temperatura. El comportamiento observado en el régimen paramagnético (220 K ≤ T ≤ 400 K) está en relación directa con la concentración catiónica nominal. Se observa una transición paramagnética-ferrimagnética a T = Tc, cuyo valor depende de la composición global del compuesto, variando entre Tc = 120 K (Co0.2NiMn1.8O4) y Tc = 210 K (Co1.2Ni0.3Mn1.5O4). Se ha observado una segunda transición a una temperatura inferior, relacionada con una segunda subred magnéticamente ordenada. Esta segunda transición ocurre a T = 60 K (Co0.6NiMn1.4O4), aumentando progresivamente con la concentración del cobalto hasta alcanzar aproximadamente 160 K. En presencia de un campo magnético externo, ambas transiciones se confunden en una sola, cuya temperatura característica Tmax decrece rápidamente en función de campos magnéticos crecientes. Se realizaron ciclos de magnetización M(H) a T = 5 K, obteniéndose ciclos típicos de materiales magnéticos blandos, con campos coercitivos pequeños. Con el objeto de estudiar posibles aplicaciones de estos materiales como termistores NTCR, se realizaron igualmente medidas eléctricas por sobre la temperatura ambiente : los valores de conductividad aumentan de un factor 200-1000 entre la temperatura ambiente y 400 C.

Published
2004

295. Additional file 1 of Organic amendments alleviate early defoliation and increase fruit yield by altering assembly patterns and of microbial communities and enzymatic activities in sandy pear (Pyrus pyrifolia)

Author

Kang, Yalong, An, Xiangrui, Ma, Yanwei, Zeng, Shaomin, Jiang, Shangtao, Wu, Wenli, Xie, Changyan, Wang, Zhonghua, Dong, Caixia, Xu, Yangchun, and Shen, Qirong

Abstract

Additional file 1: Table S1. Fertilization protocol from 2017 to 2019. CK, conventional fertilization; CK-HA, conventional fertilization combined with humic acid (HA); BIO, bio-organic fertilizer; BIO-HA, mixed application of BIO and HA. Table S2. Extracellular enzymes with corresponding commission number (EC), corresponding substrate, and the abbreviation used in this study. Table S3. Effect of organic amendments on the leaf nutrient concentrations of sandy pear. Each value represents the mean (n = 6), and standard error values are indicated with �� . Different letters indicate significant difference (P 0.6) and strong negative linear (r

Published
2021
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