Journal of Superconductivity and Novel Magnetism
·
2023
·Vol. 36
·期 7
·1737-1750
·
IF 1.8
Shan Shuo,Li Jie,Li Pengwei,Wang Yonglun,Pi Siwen,Zhao Xuan
BaFe 12− x Nb x O 19 ( x = 0.00, 0.04, 0.08, 0.12, 0.16, and 0.20) with a nominal composition for M-type hexagonal barium ferrite was prepared using solid-state sintering methods. The microstructure and magnetic properties of hexaferrite were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), and vibrating-sample magnetometry (VSM). XRD results revealed that the crystal structure of barium ferrite remained intact after Nb doping, maintaining a single barium ferrite phase. FESEM confirmed the hexagonal crystal structure of the sample. Energy-dispersive X-ray spectroscopy showed increased Nb content and decreased Fe content without the formation of other elements. FTIR revealed bands at 598 and 445 cm −1 corresponding to tetrahedral and octahedral clusters, respectively. The VSM test showed that the saturation magnetization ( M s ), residual magnetization ( M r ), and coercivity ( H c ) initially increased and then decreased with increasing Nb doping, reaching maximum values of 92.297 emu/g, 44.256 emu/g, and 3367.53 Oe, respectively, at x = 0.08.
研究领域:
材料科学
·
磁学
✓ 已验证
DOI
高影响因子
Functional Materials Letters
·
2024
·
IF 1.2
Li Li,Guang Li
A straightforward solvothermal methodology was employed to synthesize Fe 3 O 4 microspheres and Fe 3 O 4 @C hybrids, where amorphous carbon encapsulated Fe 3 O 4 microspheres. This encapsulation was achieved by meticulously controlling the reaction duration and glucose concentrations within the hydrothermal process. Analysis via X-ray diffraction and Raman spectroscopy confirmed that all specimens retained a homogeneous Fe 3 O 4 phase. Following encapsulation, the Fe 3 O 4 particles were uniformly distributed across the amorphous carbon spheres, with fine particle sizes in the hybrids measuring less than 20 nm. Magnetic characterization revealed that parameters such as saturation magnetization, remanent magnetization, and coercivity of the Fe 3 O 4 microspheres could be significantly adjusted by varying the hydrothermal reaction time. Notably, the hybrids exhibited a 5- to 10-fold increase in both coercivity and remanent magnetization when compared to the pristine Fe 3 O 4 microspheres. Nonetheless, the saturation magnetization of the hybrids reached up to 90% of that observed in bulk Fe 3 O 4 . These magnetic properties are predominantly influenced by the size effect associated with the nanostructured Fe 3 O 4 .
研究领域:
材料科学
·
纳米技术
·
磁学
·
无机合成
✓ 已验证
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Jiawei Dai,Xiangfu Meng,Yuhu Zhang,Yunjie Huang
Rice straw derived biochar shows low-cost superiority as a potential adsorbent in tetracycline (TC) removal, but limited by its poor adsorption capacity and N, P leaking risk. Herein, an alkali-acid combined and magnetization method was proposed for its modification. The sorption kinetic and isotherm data showed modification enhanced the performance for tetracycline removal with adsorption capacity up to 98.33 mg·g −1 . The strong adsorption mechanisms were dominated by hydrogen bonding and pore-filling effect due to the increase of specific surface area and pore volume. Furthermore, the effect of pH was insignificant over a pH range from 3 to 10. The strong competition between ionic and TC was identified, where Ca 2+ and PO 4 3− markedly inhibited the sorption. The enhanced TC adsorption, strong N and P removal, easy magnetic recovery, and good reusability in water samples entrusted it with good potential for wastewater treatment and rice straw resource disposal.
研究领域:
环境科学
·
生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 5
·2644-2649
·
IF 3.108
Guodong Wei,Lin Wei,Dong Wang,Yufeng Tian,Yanxue Chen,Shishen Yan,Liangmo Mei,Jun Jiao
In this report, a reversible control of Fe3O4 saturated magnetization by Li ions is demonstrated. A miniature Li ion battery (LIB) was assembled using a Fe3O4 nanoparticle layer as the active cathode. A stable magnetism modulation is realized by a nondestructive electrochemical process in which the lithium insertion results in a valence change and partial redistribution of Fe cations in the crystal structure. The relation between the discharge voltage and the chemical phases were studied by ex situ X-ray diffraction and magnetic measurement. In a suitable discharge potential range, a reversible control of Fe3O4 saturated magnetization was obtained without structural damage to the magnetic electrode. The experimental results indicate by further optimizing the LIB's performance, a large reversible change in magnetization could be realized at room temperature, suggesting the potential for future practical applications.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2024
·
IF 7.2
Chao Liu,Tieyan Chang,Shilei Wang,Shun Zhou,Xiaoli Wang,Chuanyan Fan,Lu Han,Feiyu Li,Huifen Ren,Shanpeng Wang,Yu-Sheng Chen,Junjie Zhang
Spins in strongly frustrated systems are of intense interest due to the emergence of intriguing quantum states including superconductivity and quantum spin liquid. Herein, we report the discovery of a cascade of phase transitions and large magnetic anisotropy in the averievite CsClCu5P2O10 single crystals. Under a zero field, CsClCu5P2O10 undergoes a first-order structural transition at around 224 K from high-temperature centrosymmetric P3̅m1 to low-temperature noncentrosymmetric P321 followed by an AFM transition at 13.6 K, and another AFM transition at ∼2.18 K. Based upon magnetic susceptibility and magnetization data with magnetic fields perpendicular to the ab plane, a phase diagram, consisting of a paramagnetic state, two AFM states, and two field-induced states including two magnetization plateaus, has been constructed. Our findings demonstrate that the quasi-2D CsClCu5P2O10 exhibits rich structural and metamagnetic transitions, and the averievite family is a fertile platform for exploring novel quantum states.
研究领域:
凝聚态物理学
·
量子磁性
·
强关联电子系统
✓ 已验证
DOI
高影响因子
SCRIPTA MATERIALIA
·
2021
·
IF 5.611
Lei Meng,Chu Xin Peng,Chen He,Fei Yen
The polarity of the magnetic susceptibility χ( T ) of ammonium alum NH 4 Al(SO 4 ) 2 •12H 2 O single crystals below its ferroelectric Curie temperature T C is identified to depend only on the cooling rate. To explain this, we consider reorienting distorted NH 4 + to carry weak magnetic and electric dipole moments that are linearly coupled. Slow cooling allows the dipole moments to align which enhances χ( T ) to become positive. However, due to energy degeneracy of rotational motion and geometric frustration of the NH 4 + , faster cooling rates render the system to become an orientational glass state causing χ( T ) to remain negative. Specific heat measurements also show the presence of excess entropy below a negative anomaly near 53 K. Our findings identify a possible new class of non-equilibrium system with potential applications in non-volatile memory devices.
研究领域:
物理学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 18
·18001-18014
·
IF 2.8
Xu Zhengming,Han Dexia,Li Yuan,Zhang Pingling,You Lijun,Zhao Zhengang
In this study, the FPA90-Cl resin was magnetized with supported Fe 3 O 4 particles using a chemical co-precipitation method and its removal performance of bromate and coexisting precursors was explored. The magnetized FPA90-Cl resin was structurally characterized by SEM, FT-IR, and XRD. The effects of the initial concentrations, temperature, and resin dosage on bromate and bromide ion removal in drinking water were investigated using batch experiments. The magnetized FPA90-Cl resin exhibited a high removal efficiency for bromate and bromide ions at three initial concentrations, and the residual bromate concentrations were under the maximum contaminant level (MCL) of 10 μg L −1 after 80 min. The adsorption data of bromate and bromide ion could be well described by a pseudo-first-order kinetic model ( R 2 ˃ 0.98). The bromate removal alone was further studied by varying the initial solution pH, temperature, and competitive anions. The results showed that the magnetized FPA90-Cl resin could be used over a wide pH range (4.0–9.0). The maximum sorption capacity of the magnetized FPA90-Cl resin for bromate reached 132.83 mg g −1 at 298 K. The Freundlich and Redlich-Peterson isotherm models fit the bromate adsorption equilibrium better ( R 2 ˃ 0.99) than the Langmuir isotherm model ( R 2 ˃ 0.98). The thermodynamic analysis showed that the bromate adsorption process was endothermic. The negative ΔG and positive ΔS indicated that the process was spontaneous and that randomness increased after adsorption, respectively. The competition of coexisting anions with bromate was in the order of SO 4 2− > CO 3 2− > Cl − > NO 3 − > HCO 3 − > PO 4 3− . Additionally, the magnetized FPA90-Cl resin could maintain a high bromate and bromide ion adsorption capacity after five cycles of regeneration by a 0.1 M NaCl solution.
Graphical abstract
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
PLoS One
·
2015
·Vol. 10
·期 10
·e0140560
·
IF 3.234
Paul Kyu Han,Jeffrey W. Barker,Ki Hwan Kim,Seung Hong Choi,Kyongtae Ty Bae,Sung-Hong Park
The recent blood flow and magnetization transfer (MT) technique termed alternate ascending/descending directional navigation (ALADDIN) achieves the contrast using interslice blood flow and MT effects with no separate preparation RF pulse, thereby potentially overcoming limitations of conventional methods. In this study, we examined the signal characteristics of ALADDIN as a simultaneous blood flow and MT imaging strategy, by comparing it with pseudo-continuous ASL (pCASL) and conventional MT asymmetry (MTA) methods, all of which had the same bSSFP readout. Bloch-equation simulations and experiments showed ALADDIN perfusion signals increased with flip angle, whereas MTA signals peaked at flip angle around 45°−60°. ALADDIN provided signals comparable to those of pCASL and conventional MTA methods emulating the first, second, and third prior slices of ALADDIN under the same scan conditions, suggesting ALADDIN signals to be superposition of signals from multiple labeling planes. The quantitative cerebral blood flow signals from a modified continuous ASL model overestimated the perfusion signals compared to those measured with a pulsed ASL method. Simultaneous mapping of blood flow, MTA, and MT ratio in the whole brain is feasible with ALADDIN within a clinically reasonable time, which can potentially help diagnosis of various diseases.
研究领域:
医学影像
·
神经影像
·
磁共振成像 (MRI)
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
MATERIALS & DESIGN
·
2019
·
IF 5.77
Shuying Shi,Chonghe Xu,Xinqiang Wang,Yongshuai Xie,Yuping Wang,Qing Dong,Luyi Zhu,Guanghui Zhang,Dong Xu
Magnetic fibers adsorbent has attracted more and more attention because of the large surface area and overcoming the disadvantages of easy agglomeration and difficult separation. Adding Fe 3 O 4 nanoparticles into spinning solution followed by electrospinning is a common method to prepare magnetic fibers. In this paper, a new sol-gel method was developed to prepare Fe 3 O 4 fibers, which overcame the disadvantage of low saturation magnetization due to the limited amount of magnetic nanoparticles in spinning solution, and uneven distribution of magnetic nanoparticles in the fibers. Through studying the effect of the proportion of ethanol in the solvent and the amount of solvent on the surface tension, the conductivity and viscosity of the spinning solution, and the spinning solution with the best spinnability were explored. The prepared Fe 3 O 4 fibers had high saturation magnetization and maintained excellent flexibility. They had the advantages of self-supporting without agglomeration, and were easier to magnetically separate than Fe 3 O 4 powder prepared by the same method. In addition, the adsorption and regeneration performances for Pb(II) of Fe 3 O 4 fibers were better than those of Fe 3 O 4 powder. Fe 3 O 4 fibers were suitable for heavy metal adsorbent or adsorbent core, which became another effective strategy to expand the application prospects of magnetic adsorbents.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yuwei Pan,Hongjin Guo,Minghua Zhou,Ying Zhang,Yusi Tian,Wei Wang
This study presents a novel pre-magnetized Fe 0 /ethylenediaminetetraacetic acid/air (pre-Fe 0 /EDTA/air) Fenton-like system to remove sulfamethazine (SMT). SMT removal only reached 10.6% in pre-Fe 0 /air system (0.2 g L −1 , SMT 3 mg L −1 , pH 5) while reached 88.5% in pre-Fe 0 /EDTA/air system within 1 h (0.2 g L −1 , SMT 3 mg L −1 , EDTA 2 mM, pH 5). EDTA could combine with Fe II or Fe III to keep iron soluble in the solution and the fast activation of molecular oxygen by Fe-EDTA complex could induce the fast and more production of H 2 O 2 . It was found that much more H 2 O 2 (5.1 mg L −1 ) and OH radical (26.4 μM) were produced in the pre-Fe 0 /EDTA/air system than in the pre-Fe 0 /air system (0.06 mg L −1 , 0.6 μM) within 1 h. The degradation rate of SMT (1 0 3 ) in pre-Fe 0 /EDTA/air system (38.4 min −1 ) was also 2.3 times as large as that in the Fe 0 /EDTA/air system (17.0 min −1 ), owing to the fast corrosion rate of pre-Fe 0 . 81.5 mgL −1 total Fe ions could be generated in pre-Fe 0 /EDTA/air while 53.6 mg L −1 in Fe 0 /EDTA/air. Fe 0 dosage (0.05–0.8 g L −1 ) and EDTA dosage (0–8 mM) were optimized and the optimal dosage for Fe 0 and EDTA was 0.2 g L −1 and 2 mM, respectively. The degradation rate of SMT in pre-Fe 0 /EDTA/air system were 1.6–2.9 times at different initial pH (3–6) and 2.3–3.1 times in the presence of inorganic ions (SO 4 2− , Cl − and HCO 3 − ) and natural organic matter (NOM) compared with Fe 0 /EDTA/air system. Decrease of Fe 0 contact angle in the presence of magnetization and EDTA enhanced the corrosion rate of Fe 0 . Accordingly, pre-Fe 0 /EDTA/air system would be a cost-effective and promising eco-friendly alternative for removal of SMT.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Min Zhang,Jin Wang,Xinyuan Zhan,Wusong Xu,Maolin He,Ding Ma,Zhengbo Yue
Thiocyanate (SCN − ), a non-volatile inorganic pollutant, is commonly found in various types of industrial wastewater, which is resistant to hydrolysis and has the potential to be toxic to organisms. Premagnetized iron-copper-carbon ternary micro-electrolytic filler (pre-Fe/Cu/C) was prepared to degrade SCN − . Pre-Fe/Cu/C exhibited the most significant enhancement effect on SCN − removal when magnetized for 5 min with an intensity of 100 mT, and the SCN − removal rate was the highest at an initial pH of 3.0 and an aeration rate of 1.6 L/min. The electrochemical corrosion and electron transfer in the pre-Fe/Cu/C system were confirmed through SEM, XPS , FTIR , XRD , and electrochemical tests. This resulted in the formation of more corrosion products and multiple cycles of Fe 2+ /Fe 3+ and Cu 0 /Cu + /Cu 2+ . Additionally, density functional theory (DFT) calculations and electron paramagnetic resonance (EPR) were utilized to illustrate the oxygen adsorption properties of the materials and the participation of reactive oxygen species ( 1 O 2 , ·O 2 − , and ·OH) in SCN − removal. The degradation products of SCN − were identified as SO 4 2− , HCO 3 − , NH 4 + , and N 2 . This study introduced the use of permanent magnets for the first time to enhance Fe/Cu/C ternary micro-electrolytic fillers, offering a cost-effective, versatile, and stable approach that effectively effectively enhanced the degradation of SCN − .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Applied Materials Today
·
2024
·
IF 7.2
Chuding Zhang,Decai Li,Wenxi Zhao,Shilin Nie,Jingwei Yang
The preparation of high-performance magnetic fluids with high viscosity, high saturation magnetization and high stability, has remained a pivotal challenge limiting the advancement of associated applications. In the present study, we synthesized modified magnetic nanoparticles through an innovative approach combining in-situ carbon nanotube (CNT) generation with chemical co-precipitation. These nanoparticles were then co-coated with OA/PIBA, resulting in the preparation of advanced PAO20-based magnetic fluids. The effects of CNT modification on particle microstructure and magnetic properties were studied by transmission electron microscopy and vibrating sample magnetometer, the magnetoviscous properties of magnetic fluids were studied by a rotating rheometer equipped with a magnetic field module, and the stability of the prepared magnetic fluids under a strong magnetic field was tested by a self-made LC oscillation circuit. The results show that the saturation magnetization of the prepared magnetic fluids surpasses 32 emu/g, while their viscosity reaches a remarkable 6625 mPa·s (at 0.24 T, 100 1/s shear rate and 25 °C), which is significantly higher than that of traditional magnetic fluids (usually about 100 mPa·s). Furthermore, when exposed to a 0.6 T magnetic field, the magnetic fluids could exhibit Rosensweig instability that persists for over 468 h. The stability is at least 93 times superior to that of unmodified PAO20-based magnetic fluids. Based on these encouraging results, it can be fully predicted that the CNT-modified PAO20-based magnetic fluids developed in this study will play a pivotal role in various applications, including sealing, lubrication, and vibration reduction. Their exceptional properties will hold immense promise for numerous engineering applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）