Crystals
·
2021
·Vol. 11
·期 3
·278
·
IF 2.589
Liangqun Yang,Hongli Suo,Lin Ma,Min Liu,Wanli Zhao,Jianhua Liu,Lei Wang,Zili Zhang,Qiuliang Wang
In this study, boron powder with different particle sizes was purified by both chemical and heat treatment methods. The reduction in the particle size can improve the chemical purification with no effort on the heat treatment. The superconducting properties of the powder drastically changed even with only a partial elimination of oxygen. On the one hand, less oxygen content resulted in highTcandJcvalues under the low magnetic field, and most importantly, a significant improvement in the superconducting connectivity (Afvalue). On the other hand, the degradation ofJcunder a high field and a change in the pinning mechanism were also found, along with decreasing oxygen. This result indicated that oxygen, probably MgO, might act as the pinning center and as an obstacle for the supercurrent in MgB2at the same time. This work paves the way for obtaining pure oxygen-free MgB2and understanding the real effect of oxygen in MgB2.Keywords:boron powder;purification;particle size;MgB2;superconducting connectivity
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Liangliang Tang,Dongxu Yao,Yongfeng Xia,Jun Zhao,Ming Zhu,Yu-Ping Zeng
Gas-pressure-sintered silicon nitride (Si 3 N 4 ) ceramics were increased in density and mechanical properties without impairing the thermal conductivity by the addition of TiH 2 . After annealing treatment of the sintered ceramics, the inherent properties were further improved, the grain boundary phases on the surface were evaporated, and the rugged surface microstructure was formed. Si 3 N 4 ceramics before and after the annealing treatment were then joined with oxygen-free copper (OFC) foil using Ag-Cu-TiH 2 filler. Two interfacial structures, planar and rugged, were formed in the Si 3 N 4 ceramic/OFC foil joints, respectively. The peeling strength of the joints brazed with annealed Si 3 N 4 ceramics was improved, attributed to the increased inherent strength of the ceramics and rugged interface of the joints. The joint reached a maximum peeling strength of 25.08 N/mm, in which the fracture occurred mainly in the surface layer of the Si 3 N 4 ceramic as well as between the brazing alloy and the OFC foil.
研究领域:
材料科学
·
焊接工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2022
·
IF 9.417
Qianqian Chen,Panpan Lin,Xuanyu Du,Hiroyuki Inoue,Kazuro Kizaki,Tiesong Lin,Peng He
A new low-temperature magnetic Bi 2 O 3 -CoO-Fe 2 O 3 -B 2 O 3 (BCFB) glass was designed to acquire magnetic yttrium iron garnet (YIG/YIG) joint. This paper investigated the thermal behavior of BCFB glass and its wettability on YIG. The microstructural evolution, mechanical and electromagnetic properties of YIG/YIG joint were systematically studied. CoFe 2 O 4 nuclei were gradually formed, growing up into nano-scale CoFe 2 O 4 crystals in the glass seam. Meanwhile, some CoFe 2 O 4 crystals grew up excessively by swallowing nano CoFe 2 O 4 , reaching microns. YBO 3 reaction layer was formed and grew into YBO 3 whiskers at the interface of YIG/glass with the brazing temperature increasing. The joint shear strength increased, reaching a maximum of 85.2 MPa at 775 °C under the collaborative reinforcement of well-integrated interface and glass-ceramic seam, then declined due to the aggravative reaction. The dielectric constant of YIG/YIG joints decreased with the brazing temperature increasing, varying from 18.5 to 16.6 at the frequency of 10 MHz. AFM/MFM and VSM analyses indicate that the glass seam performed magnetic property. The saturation magnetization of BCFB glass reached about 4.2 emu/g and 5.0 emu/g heat-treated at 750 °C and 775 °C, respectively, which could effectively enhance the magnetism of the glass seam.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Haibo Wu,Yinsheng Li,Xuejian Liu,Zhengren Huang,Dongliang Jiang
In order to improve the connectivity between pores of gelcasted and solid-state-sintered SiC (S-SiC) foams, we utilized the synergetic poring mechanism of direct foaming and sacrificial solid template through introducing organic micro-beads into aqueous foamed SiC-B 4 C-C suspensions. The addition of micro-beads accelerated the formation of more bubble-derived pores in S-SiC foams, and generated abundant bead-derived pores in the bubble-derived-pore struts and partial-sintering-derived pores between SiC grains as well. This multiple pore microstructures induced excellent connectivity between pores and an ultrahigh porosity of 89.5%. Consequently, an outstanding nitrogen gas permeability of 9.2 × 10 −11 m 2 was acquired under the condition of a superior compressive strength of 2.2 ± 0.4 MPa.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Small Methods
·
2024
·
IF 10.7
Qi-Sheng Huang,Yan Ma,Yan-Long Luo,Dong-Ping Li,Cheng-Hui Li,Yong-Xiu Li,Jing-Lin Zuo
Polymer materials formed by conventional metal-ligand bonds have very low branch functionality, the crosslinker of such polymer usually consists of 2–4 polymer chains and a single metal ion. Thus, these materials are weak, soft, humidity-sensitive, and unable to withstand their shape under long-term service. In this work, a new hyperbranched metal–organic cluster (MOC) crosslinker containing up to 16 vinyl groups is prepared by a straightforward coordination reaction. Compared with the current typical synthesis of metal–organic cages (MOCs) or metal–organic-polyhedra (MOP) crosslinkers with complex operations and low yield, the preparation of the MOC is simple and gram-scale. Thus, MOC can serve as a high-connectivity crosslinker to construct hyper-crosslinked polymer networks. The as-prepared elastomer exhibits mechanical robustness, creep-resistance, and humidity-stability. Besides, the elastomer possesses self-healing and recyclability at mild condition as well as fluorescence stability. These impressive comprehensive properties are proven to originate from the hyper-crosslinked topological structure and microphase-separated morphology. The MOC-driven hyper-crosslinked elastomers provide a new solution for the construction of mechanically robust, durable, and multifunctional polymers.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2020
·
IF 6.306
Sijie Liu,Leina Dou,Xiaolin Yao,Wentao Zhang,Bingxin Zhao,Zonghan Wang,Yanwei Ji,Jing Sun,Baocheng Xu,Daohong Zhang,Jianlong Wang
Currently, the low sensitivity and poor binding stability of detection probe prepared via electrostatic adsorption have become the dilemmas of colloidal gold-based lateral flow immunoassays (Au-LFIAs). In this connection, polydopamine nanospheres (PDA NPs) with an eminent covalent connectivity property were introduced as a promising substitute to improve the stability of probe and sensitivity of LFIA. Whereafter, the PDA NPs-based LFIA was applied for the monitoring of furazolidone (FZD) in food samples because of the potential carcinogenic/mutagenic effects to human of its metabolite (3-amino-2-oxazolidinone, AOZ). Compared with electrostatic adsorption, the binding stability of PDA NPs-based probes was superior. And, as expected, the PDA NPs-based LFIA biosensor exhibited higher sensitivity than that of the Au-LFIA with a detection limit of 3.5 ng mL −1 for AOZ by naked-eye readout. Based on the significant enhanced binding stability and sensitivity, the PDA NPs-based LFIA is of certain spreading value for detecting other analytes.
研究领域:
纳米技术
·
分析化学
·
食品安全
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biosensors-Basel
·
2022
·Vol. 12
·期 7
·546
·
IF 5.743
Shihong Xu,Yu Deng,Jinping Luo,Yaoyao Liu,Enhui He,Yan Yang,Kui Zhang,Longze Sha,Yuchun Dai,Tao Ming,Yilin Song,Luyi Jing,Chengyu Zhuang,Qi Xu,Xinxia Cai
Both the cellular- and population-level properties of involved neurons are essential for unveiling the learning and memory functions of the brain. To give equal attention to these two aspects, neural sensors based on microelectrode arrays (MEAs) have been in the limelight due to their noninvasive detection and regulation capabilities. Here, we fabricated a neural sensor using carboxylated graphene/3,4-ethylenedioxythiophene:polystyrenesulfonate (cGO/PEDOT:PSS), which is effective in sensing and monitoring neuronal electrophysiological activity in vitro for a long time. The cGO/PEDOT:PSS-modified microelectrodes exhibited a lower electrochemical impedance (7.26 ± 0.29 kΩ), higher charge storage capacity (7.53 ± 0.34 mC/cm2), and improved charge injection (3.11 ± 0.25 mC/cm2). In addition, their performance was maintained after 2 to 4 weeks of long-term cell culture and 50,000 stimulation pulses. During neural network training, the sensors were able to induce learning function in hippocampal neurons through precise electrical stimulation and simultaneously detect changes in neural activity at multiple levels. At the cellular level, not only were three kinds of transient responses to electrical stimulation sensed, but electrical stimulation was also found to affect inhibitory neurons more than excitatory neurons. As for the population level, changes in connectivity and firing synchrony were identified. The cGO/PEDOT:PSS-based neural sensor offers an excellent tool in brain function development and neurological disease treatment.Keywords:neural sensor;porous graphene;PEDOT;neurons;learning
研究领域:
神经科学
·
生物医学工程
·
材料科学
·
电生理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）